1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016 Facebook
4 * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
6 #include <uapi/linux/btf.h>
7 #include <linux/kernel.h>
8 #include <linux/types.h>
9 #include <linux/slab.h>
10 #include <linux/bpf.h>
11 #include <linux/btf.h>
12 #include <linux/bpf_verifier.h>
13 #include <linux/filter.h>
14 #include <net/netlink.h>
15 #include <linux/file.h>
16 #include <linux/vmalloc.h>
17 #include <linux/stringify.h>
18 #include <linux/bsearch.h>
19 #include <linux/sort.h>
20 #include <linux/perf_event.h>
21 #include <linux/ctype.h>
22 #include <linux/error-injection.h>
23 #include <linux/bpf_lsm.h>
24 #include <linux/btf_ids.h>
28 static const struct bpf_verifier_ops
* const bpf_verifier_ops
[] = {
29 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
30 [_id] = & _name ## _verifier_ops,
31 #define BPF_MAP_TYPE(_id, _ops)
32 #define BPF_LINK_TYPE(_id, _name)
33 #include <linux/bpf_types.h>
39 /* bpf_check() is a static code analyzer that walks eBPF program
40 * instruction by instruction and updates register/stack state.
41 * All paths of conditional branches are analyzed until 'bpf_exit' insn.
43 * The first pass is depth-first-search to check that the program is a DAG.
44 * It rejects the following programs:
45 * - larger than BPF_MAXINSNS insns
46 * - if loop is present (detected via back-edge)
47 * - unreachable insns exist (shouldn't be a forest. program = one function)
48 * - out of bounds or malformed jumps
49 * The second pass is all possible path descent from the 1st insn.
50 * Since it's analyzing all pathes through the program, the length of the
51 * analysis is limited to 64k insn, which may be hit even if total number of
52 * insn is less then 4K, but there are too many branches that change stack/regs.
53 * Number of 'branches to be analyzed' is limited to 1k
55 * On entry to each instruction, each register has a type, and the instruction
56 * changes the types of the registers depending on instruction semantics.
57 * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
60 * All registers are 64-bit.
61 * R0 - return register
62 * R1-R5 argument passing registers
63 * R6-R9 callee saved registers
64 * R10 - frame pointer read-only
66 * At the start of BPF program the register R1 contains a pointer to bpf_context
67 * and has type PTR_TO_CTX.
69 * Verifier tracks arithmetic operations on pointers in case:
70 * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
71 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
72 * 1st insn copies R10 (which has FRAME_PTR) type into R1
73 * and 2nd arithmetic instruction is pattern matched to recognize
74 * that it wants to construct a pointer to some element within stack.
75 * So after 2nd insn, the register R1 has type PTR_TO_STACK
76 * (and -20 constant is saved for further stack bounds checking).
77 * Meaning that this reg is a pointer to stack plus known immediate constant.
79 * Most of the time the registers have SCALAR_VALUE type, which
80 * means the register has some value, but it's not a valid pointer.
81 * (like pointer plus pointer becomes SCALAR_VALUE type)
83 * When verifier sees load or store instructions the type of base register
84 * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
85 * four pointer types recognized by check_mem_access() function.
87 * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
88 * and the range of [ptr, ptr + map's value_size) is accessible.
90 * registers used to pass values to function calls are checked against
91 * function argument constraints.
93 * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
94 * It means that the register type passed to this function must be
95 * PTR_TO_STACK and it will be used inside the function as
96 * 'pointer to map element key'
98 * For example the argument constraints for bpf_map_lookup_elem():
99 * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
100 * .arg1_type = ARG_CONST_MAP_PTR,
101 * .arg2_type = ARG_PTR_TO_MAP_KEY,
103 * ret_type says that this function returns 'pointer to map elem value or null'
104 * function expects 1st argument to be a const pointer to 'struct bpf_map' and
105 * 2nd argument should be a pointer to stack, which will be used inside
106 * the helper function as a pointer to map element key.
108 * On the kernel side the helper function looks like:
109 * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
111 * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
112 * void *key = (void *) (unsigned long) r2;
115 * here kernel can access 'key' and 'map' pointers safely, knowing that
116 * [key, key + map->key_size) bytes are valid and were initialized on
117 * the stack of eBPF program.
120 * Corresponding eBPF program may look like:
121 * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR
122 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
123 * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP
124 * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
125 * here verifier looks at prototype of map_lookup_elem() and sees:
126 * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
127 * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
129 * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
130 * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
131 * and were initialized prior to this call.
132 * If it's ok, then verifier allows this BPF_CALL insn and looks at
133 * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
134 * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
135 * returns ether pointer to map value or NULL.
137 * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
138 * insn, the register holding that pointer in the true branch changes state to
139 * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
140 * branch. See check_cond_jmp_op().
142 * After the call R0 is set to return type of the function and registers R1-R5
143 * are set to NOT_INIT to indicate that they are no longer readable.
145 * The following reference types represent a potential reference to a kernel
146 * resource which, after first being allocated, must be checked and freed by
148 * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
150 * When the verifier sees a helper call return a reference type, it allocates a
151 * pointer id for the reference and stores it in the current function state.
152 * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
153 * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
154 * passes through a NULL-check conditional. For the branch wherein the state is
155 * changed to CONST_IMM, the verifier releases the reference.
157 * For each helper function that allocates a reference, such as
158 * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
159 * bpf_sk_release(). When a reference type passes into the release function,
160 * the verifier also releases the reference. If any unchecked or unreleased
161 * reference remains at the end of the program, the verifier rejects it.
164 /* verifier_state + insn_idx are pushed to stack when branch is encountered */
165 struct bpf_verifier_stack_elem
{
166 /* verifer state is 'st'
167 * before processing instruction 'insn_idx'
168 * and after processing instruction 'prev_insn_idx'
170 struct bpf_verifier_state st
;
173 struct bpf_verifier_stack_elem
*next
;
174 /* length of verifier log at the time this state was pushed on stack */
178 #define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192
179 #define BPF_COMPLEXITY_LIMIT_STATES 64
181 #define BPF_MAP_KEY_POISON (1ULL << 63)
182 #define BPF_MAP_KEY_SEEN (1ULL << 62)
184 #define BPF_MAP_PTR_UNPRIV 1UL
185 #define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \
186 POISON_POINTER_DELTA))
187 #define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
189 static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data
*aux
)
191 return BPF_MAP_PTR(aux
->map_ptr_state
) == BPF_MAP_PTR_POISON
;
194 static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data
*aux
)
196 return aux
->map_ptr_state
& BPF_MAP_PTR_UNPRIV
;
199 static void bpf_map_ptr_store(struct bpf_insn_aux_data
*aux
,
200 const struct bpf_map
*map
, bool unpriv
)
202 BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON
& BPF_MAP_PTR_UNPRIV
);
203 unpriv
|= bpf_map_ptr_unpriv(aux
);
204 aux
->map_ptr_state
= (unsigned long)map
|
205 (unpriv
? BPF_MAP_PTR_UNPRIV
: 0UL);
208 static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data
*aux
)
210 return aux
->map_key_state
& BPF_MAP_KEY_POISON
;
213 static bool bpf_map_key_unseen(const struct bpf_insn_aux_data
*aux
)
215 return !(aux
->map_key_state
& BPF_MAP_KEY_SEEN
);
218 static u64
bpf_map_key_immediate(const struct bpf_insn_aux_data
*aux
)
220 return aux
->map_key_state
& ~(BPF_MAP_KEY_SEEN
| BPF_MAP_KEY_POISON
);
223 static void bpf_map_key_store(struct bpf_insn_aux_data
*aux
, u64 state
)
225 bool poisoned
= bpf_map_key_poisoned(aux
);
227 aux
->map_key_state
= state
| BPF_MAP_KEY_SEEN
|
228 (poisoned
? BPF_MAP_KEY_POISON
: 0ULL);
231 static bool bpf_pseudo_call(const struct bpf_insn
*insn
)
233 return insn
->code
== (BPF_JMP
| BPF_CALL
) &&
234 insn
->src_reg
== BPF_PSEUDO_CALL
;
237 static bool bpf_pseudo_kfunc_call(const struct bpf_insn
*insn
)
239 return insn
->code
== (BPF_JMP
| BPF_CALL
) &&
240 insn
->src_reg
== BPF_PSEUDO_KFUNC_CALL
;
243 static bool bpf_pseudo_func(const struct bpf_insn
*insn
)
245 return insn
->code
== (BPF_LD
| BPF_IMM
| BPF_DW
) &&
246 insn
->src_reg
== BPF_PSEUDO_FUNC
;
249 struct bpf_call_arg_meta
{
250 struct bpf_map
*map_ptr
;
266 struct btf
*btf_vmlinux
;
268 static DEFINE_MUTEX(bpf_verifier_lock
);
270 static const struct bpf_line_info
*
271 find_linfo(const struct bpf_verifier_env
*env
, u32 insn_off
)
273 const struct bpf_line_info
*linfo
;
274 const struct bpf_prog
*prog
;
278 nr_linfo
= prog
->aux
->nr_linfo
;
280 if (!nr_linfo
|| insn_off
>= prog
->len
)
283 linfo
= prog
->aux
->linfo
;
284 for (i
= 1; i
< nr_linfo
; i
++)
285 if (insn_off
< linfo
[i
].insn_off
)
288 return &linfo
[i
- 1];
291 void bpf_verifier_vlog(struct bpf_verifier_log
*log
, const char *fmt
,
296 n
= vscnprintf(log
->kbuf
, BPF_VERIFIER_TMP_LOG_SIZE
, fmt
, args
);
298 WARN_ONCE(n
>= BPF_VERIFIER_TMP_LOG_SIZE
- 1,
299 "verifier log line truncated - local buffer too short\n");
301 n
= min(log
->len_total
- log
->len_used
- 1, n
);
304 if (log
->level
== BPF_LOG_KERNEL
) {
305 pr_err("BPF:%s\n", log
->kbuf
);
308 if (!copy_to_user(log
->ubuf
+ log
->len_used
, log
->kbuf
, n
+ 1))
314 static void bpf_vlog_reset(struct bpf_verifier_log
*log
, u32 new_pos
)
318 if (!bpf_verifier_log_needed(log
))
321 log
->len_used
= new_pos
;
322 if (put_user(zero
, log
->ubuf
+ new_pos
))
326 /* log_level controls verbosity level of eBPF verifier.
327 * bpf_verifier_log_write() is used to dump the verification trace to the log,
328 * so the user can figure out what's wrong with the program
330 __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env
*env
,
331 const char *fmt
, ...)
335 if (!bpf_verifier_log_needed(&env
->log
))
339 bpf_verifier_vlog(&env
->log
, fmt
, args
);
342 EXPORT_SYMBOL_GPL(bpf_verifier_log_write
);
344 __printf(2, 3) static void verbose(void *private_data
, const char *fmt
, ...)
346 struct bpf_verifier_env
*env
= private_data
;
349 if (!bpf_verifier_log_needed(&env
->log
))
353 bpf_verifier_vlog(&env
->log
, fmt
, args
);
357 __printf(2, 3) void bpf_log(struct bpf_verifier_log
*log
,
358 const char *fmt
, ...)
362 if (!bpf_verifier_log_needed(log
))
366 bpf_verifier_vlog(log
, fmt
, args
);
370 static const char *ltrim(const char *s
)
378 __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env
*env
,
380 const char *prefix_fmt
, ...)
382 const struct bpf_line_info
*linfo
;
384 if (!bpf_verifier_log_needed(&env
->log
))
387 linfo
= find_linfo(env
, insn_off
);
388 if (!linfo
|| linfo
== env
->prev_linfo
)
394 va_start(args
, prefix_fmt
);
395 bpf_verifier_vlog(&env
->log
, prefix_fmt
, args
);
400 ltrim(btf_name_by_offset(env
->prog
->aux
->btf
,
403 env
->prev_linfo
= linfo
;
406 static void verbose_invalid_scalar(struct bpf_verifier_env
*env
,
407 struct bpf_reg_state
*reg
,
408 struct tnum
*range
, const char *ctx
,
409 const char *reg_name
)
413 verbose(env
, "At %s the register %s ", ctx
, reg_name
);
414 if (!tnum_is_unknown(reg
->var_off
)) {
415 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
416 verbose(env
, "has value %s", tn_buf
);
418 verbose(env
, "has unknown scalar value");
420 tnum_strn(tn_buf
, sizeof(tn_buf
), *range
);
421 verbose(env
, " should have been in %s\n", tn_buf
);
424 static bool type_is_pkt_pointer(enum bpf_reg_type type
)
426 return type
== PTR_TO_PACKET
||
427 type
== PTR_TO_PACKET_META
;
430 static bool type_is_sk_pointer(enum bpf_reg_type type
)
432 return type
== PTR_TO_SOCKET
||
433 type
== PTR_TO_SOCK_COMMON
||
434 type
== PTR_TO_TCP_SOCK
||
435 type
== PTR_TO_XDP_SOCK
;
438 static bool reg_type_not_null(enum bpf_reg_type type
)
440 return type
== PTR_TO_SOCKET
||
441 type
== PTR_TO_TCP_SOCK
||
442 type
== PTR_TO_MAP_VALUE
||
443 type
== PTR_TO_MAP_KEY
||
444 type
== PTR_TO_SOCK_COMMON
;
447 static bool reg_type_may_be_null(enum bpf_reg_type type
)
449 return type
== PTR_TO_MAP_VALUE_OR_NULL
||
450 type
== PTR_TO_SOCKET_OR_NULL
||
451 type
== PTR_TO_SOCK_COMMON_OR_NULL
||
452 type
== PTR_TO_TCP_SOCK_OR_NULL
||
453 type
== PTR_TO_BTF_ID_OR_NULL
||
454 type
== PTR_TO_MEM_OR_NULL
||
455 type
== PTR_TO_RDONLY_BUF_OR_NULL
||
456 type
== PTR_TO_RDWR_BUF_OR_NULL
;
459 static bool reg_may_point_to_spin_lock(const struct bpf_reg_state
*reg
)
461 return reg
->type
== PTR_TO_MAP_VALUE
&&
462 map_value_has_spin_lock(reg
->map_ptr
);
465 static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type
)
467 return type
== PTR_TO_SOCKET
||
468 type
== PTR_TO_SOCKET_OR_NULL
||
469 type
== PTR_TO_TCP_SOCK
||
470 type
== PTR_TO_TCP_SOCK_OR_NULL
||
471 type
== PTR_TO_MEM
||
472 type
== PTR_TO_MEM_OR_NULL
;
475 static bool arg_type_may_be_refcounted(enum bpf_arg_type type
)
477 return type
== ARG_PTR_TO_SOCK_COMMON
;
480 static bool arg_type_may_be_null(enum bpf_arg_type type
)
482 return type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
||
483 type
== ARG_PTR_TO_MEM_OR_NULL
||
484 type
== ARG_PTR_TO_CTX_OR_NULL
||
485 type
== ARG_PTR_TO_SOCKET_OR_NULL
||
486 type
== ARG_PTR_TO_ALLOC_MEM_OR_NULL
||
487 type
== ARG_PTR_TO_STACK_OR_NULL
;
490 /* Determine whether the function releases some resources allocated by another
491 * function call. The first reference type argument will be assumed to be
492 * released by release_reference().
494 static bool is_release_function(enum bpf_func_id func_id
)
496 return func_id
== BPF_FUNC_sk_release
||
497 func_id
== BPF_FUNC_ringbuf_submit
||
498 func_id
== BPF_FUNC_ringbuf_discard
;
501 static bool may_be_acquire_function(enum bpf_func_id func_id
)
503 return func_id
== BPF_FUNC_sk_lookup_tcp
||
504 func_id
== BPF_FUNC_sk_lookup_udp
||
505 func_id
== BPF_FUNC_skc_lookup_tcp
||
506 func_id
== BPF_FUNC_map_lookup_elem
||
507 func_id
== BPF_FUNC_ringbuf_reserve
;
510 static bool is_acquire_function(enum bpf_func_id func_id
,
511 const struct bpf_map
*map
)
513 enum bpf_map_type map_type
= map
? map
->map_type
: BPF_MAP_TYPE_UNSPEC
;
515 if (func_id
== BPF_FUNC_sk_lookup_tcp
||
516 func_id
== BPF_FUNC_sk_lookup_udp
||
517 func_id
== BPF_FUNC_skc_lookup_tcp
||
518 func_id
== BPF_FUNC_ringbuf_reserve
)
521 if (func_id
== BPF_FUNC_map_lookup_elem
&&
522 (map_type
== BPF_MAP_TYPE_SOCKMAP
||
523 map_type
== BPF_MAP_TYPE_SOCKHASH
))
529 static bool is_ptr_cast_function(enum bpf_func_id func_id
)
531 return func_id
== BPF_FUNC_tcp_sock
||
532 func_id
== BPF_FUNC_sk_fullsock
||
533 func_id
== BPF_FUNC_skc_to_tcp_sock
||
534 func_id
== BPF_FUNC_skc_to_tcp6_sock
||
535 func_id
== BPF_FUNC_skc_to_udp6_sock
||
536 func_id
== BPF_FUNC_skc_to_tcp_timewait_sock
||
537 func_id
== BPF_FUNC_skc_to_tcp_request_sock
;
540 static bool is_cmpxchg_insn(const struct bpf_insn
*insn
)
542 return BPF_CLASS(insn
->code
) == BPF_STX
&&
543 BPF_MODE(insn
->code
) == BPF_ATOMIC
&&
544 insn
->imm
== BPF_CMPXCHG
;
547 /* string representation of 'enum bpf_reg_type' */
548 static const char * const reg_type_str
[] = {
550 [SCALAR_VALUE
] = "inv",
551 [PTR_TO_CTX
] = "ctx",
552 [CONST_PTR_TO_MAP
] = "map_ptr",
553 [PTR_TO_MAP_VALUE
] = "map_value",
554 [PTR_TO_MAP_VALUE_OR_NULL
] = "map_value_or_null",
555 [PTR_TO_STACK
] = "fp",
556 [PTR_TO_PACKET
] = "pkt",
557 [PTR_TO_PACKET_META
] = "pkt_meta",
558 [PTR_TO_PACKET_END
] = "pkt_end",
559 [PTR_TO_FLOW_KEYS
] = "flow_keys",
560 [PTR_TO_SOCKET
] = "sock",
561 [PTR_TO_SOCKET_OR_NULL
] = "sock_or_null",
562 [PTR_TO_SOCK_COMMON
] = "sock_common",
563 [PTR_TO_SOCK_COMMON_OR_NULL
] = "sock_common_or_null",
564 [PTR_TO_TCP_SOCK
] = "tcp_sock",
565 [PTR_TO_TCP_SOCK_OR_NULL
] = "tcp_sock_or_null",
566 [PTR_TO_TP_BUFFER
] = "tp_buffer",
567 [PTR_TO_XDP_SOCK
] = "xdp_sock",
568 [PTR_TO_BTF_ID
] = "ptr_",
569 [PTR_TO_BTF_ID_OR_NULL
] = "ptr_or_null_",
570 [PTR_TO_PERCPU_BTF_ID
] = "percpu_ptr_",
571 [PTR_TO_MEM
] = "mem",
572 [PTR_TO_MEM_OR_NULL
] = "mem_or_null",
573 [PTR_TO_RDONLY_BUF
] = "rdonly_buf",
574 [PTR_TO_RDONLY_BUF_OR_NULL
] = "rdonly_buf_or_null",
575 [PTR_TO_RDWR_BUF
] = "rdwr_buf",
576 [PTR_TO_RDWR_BUF_OR_NULL
] = "rdwr_buf_or_null",
577 [PTR_TO_FUNC
] = "func",
578 [PTR_TO_MAP_KEY
] = "map_key",
581 static char slot_type_char
[] = {
582 [STACK_INVALID
] = '?',
588 static void print_liveness(struct bpf_verifier_env
*env
,
589 enum bpf_reg_liveness live
)
591 if (live
& (REG_LIVE_READ
| REG_LIVE_WRITTEN
| REG_LIVE_DONE
))
593 if (live
& REG_LIVE_READ
)
595 if (live
& REG_LIVE_WRITTEN
)
597 if (live
& REG_LIVE_DONE
)
601 static struct bpf_func_state
*func(struct bpf_verifier_env
*env
,
602 const struct bpf_reg_state
*reg
)
604 struct bpf_verifier_state
*cur
= env
->cur_state
;
606 return cur
->frame
[reg
->frameno
];
609 static const char *kernel_type_name(const struct btf
* btf
, u32 id
)
611 return btf_name_by_offset(btf
, btf_type_by_id(btf
, id
)->name_off
);
614 static void print_verifier_state(struct bpf_verifier_env
*env
,
615 const struct bpf_func_state
*state
)
617 const struct bpf_reg_state
*reg
;
622 verbose(env
, " frame%d:", state
->frameno
);
623 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
624 reg
= &state
->regs
[i
];
628 verbose(env
, " R%d", i
);
629 print_liveness(env
, reg
->live
);
630 verbose(env
, "=%s", reg_type_str
[t
]);
631 if (t
== SCALAR_VALUE
&& reg
->precise
)
633 if ((t
== SCALAR_VALUE
|| t
== PTR_TO_STACK
) &&
634 tnum_is_const(reg
->var_off
)) {
635 /* reg->off should be 0 for SCALAR_VALUE */
636 verbose(env
, "%lld", reg
->var_off
.value
+ reg
->off
);
638 if (t
== PTR_TO_BTF_ID
||
639 t
== PTR_TO_BTF_ID_OR_NULL
||
640 t
== PTR_TO_PERCPU_BTF_ID
)
641 verbose(env
, "%s", kernel_type_name(reg
->btf
, reg
->btf_id
));
642 verbose(env
, "(id=%d", reg
->id
);
643 if (reg_type_may_be_refcounted_or_null(t
))
644 verbose(env
, ",ref_obj_id=%d", reg
->ref_obj_id
);
645 if (t
!= SCALAR_VALUE
)
646 verbose(env
, ",off=%d", reg
->off
);
647 if (type_is_pkt_pointer(t
))
648 verbose(env
, ",r=%d", reg
->range
);
649 else if (t
== CONST_PTR_TO_MAP
||
650 t
== PTR_TO_MAP_KEY
||
651 t
== PTR_TO_MAP_VALUE
||
652 t
== PTR_TO_MAP_VALUE_OR_NULL
)
653 verbose(env
, ",ks=%d,vs=%d",
654 reg
->map_ptr
->key_size
,
655 reg
->map_ptr
->value_size
);
656 if (tnum_is_const(reg
->var_off
)) {
657 /* Typically an immediate SCALAR_VALUE, but
658 * could be a pointer whose offset is too big
661 verbose(env
, ",imm=%llx", reg
->var_off
.value
);
663 if (reg
->smin_value
!= reg
->umin_value
&&
664 reg
->smin_value
!= S64_MIN
)
665 verbose(env
, ",smin_value=%lld",
666 (long long)reg
->smin_value
);
667 if (reg
->smax_value
!= reg
->umax_value
&&
668 reg
->smax_value
!= S64_MAX
)
669 verbose(env
, ",smax_value=%lld",
670 (long long)reg
->smax_value
);
671 if (reg
->umin_value
!= 0)
672 verbose(env
, ",umin_value=%llu",
673 (unsigned long long)reg
->umin_value
);
674 if (reg
->umax_value
!= U64_MAX
)
675 verbose(env
, ",umax_value=%llu",
676 (unsigned long long)reg
->umax_value
);
677 if (!tnum_is_unknown(reg
->var_off
)) {
680 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
681 verbose(env
, ",var_off=%s", tn_buf
);
683 if (reg
->s32_min_value
!= reg
->smin_value
&&
684 reg
->s32_min_value
!= S32_MIN
)
685 verbose(env
, ",s32_min_value=%d",
686 (int)(reg
->s32_min_value
));
687 if (reg
->s32_max_value
!= reg
->smax_value
&&
688 reg
->s32_max_value
!= S32_MAX
)
689 verbose(env
, ",s32_max_value=%d",
690 (int)(reg
->s32_max_value
));
691 if (reg
->u32_min_value
!= reg
->umin_value
&&
692 reg
->u32_min_value
!= U32_MIN
)
693 verbose(env
, ",u32_min_value=%d",
694 (int)(reg
->u32_min_value
));
695 if (reg
->u32_max_value
!= reg
->umax_value
&&
696 reg
->u32_max_value
!= U32_MAX
)
697 verbose(env
, ",u32_max_value=%d",
698 (int)(reg
->u32_max_value
));
703 for (i
= 0; i
< state
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
704 char types_buf
[BPF_REG_SIZE
+ 1];
708 for (j
= 0; j
< BPF_REG_SIZE
; j
++) {
709 if (state
->stack
[i
].slot_type
[j
] != STACK_INVALID
)
711 types_buf
[j
] = slot_type_char
[
712 state
->stack
[i
].slot_type
[j
]];
714 types_buf
[BPF_REG_SIZE
] = 0;
717 verbose(env
, " fp%d", (-i
- 1) * BPF_REG_SIZE
);
718 print_liveness(env
, state
->stack
[i
].spilled_ptr
.live
);
719 if (state
->stack
[i
].slot_type
[0] == STACK_SPILL
) {
720 reg
= &state
->stack
[i
].spilled_ptr
;
722 verbose(env
, "=%s", reg_type_str
[t
]);
723 if (t
== SCALAR_VALUE
&& reg
->precise
)
725 if (t
== SCALAR_VALUE
&& tnum_is_const(reg
->var_off
))
726 verbose(env
, "%lld", reg
->var_off
.value
+ reg
->off
);
728 verbose(env
, "=%s", types_buf
);
731 if (state
->acquired_refs
&& state
->refs
[0].id
) {
732 verbose(env
, " refs=%d", state
->refs
[0].id
);
733 for (i
= 1; i
< state
->acquired_refs
; i
++)
734 if (state
->refs
[i
].id
)
735 verbose(env
, ",%d", state
->refs
[i
].id
);
740 #define COPY_STATE_FN(NAME, COUNT, FIELD, SIZE) \
741 static int copy_##NAME##_state(struct bpf_func_state *dst, \
742 const struct bpf_func_state *src) \
746 if (WARN_ON_ONCE(dst->COUNT < src->COUNT)) { \
747 /* internal bug, make state invalid to reject the program */ \
748 memset(dst, 0, sizeof(*dst)); \
751 memcpy(dst->FIELD, src->FIELD, \
752 sizeof(*src->FIELD) * (src->COUNT / SIZE)); \
755 /* copy_reference_state() */
756 COPY_STATE_FN(reference
, acquired_refs
, refs
, 1)
757 /* copy_stack_state() */
758 COPY_STATE_FN(stack
, allocated_stack
, stack
, BPF_REG_SIZE
)
761 #define REALLOC_STATE_FN(NAME, COUNT, FIELD, SIZE) \
762 static int realloc_##NAME##_state(struct bpf_func_state *state, int size, \
765 u32 old_size = state->COUNT; \
766 struct bpf_##NAME##_state *new_##FIELD; \
767 int slot = size / SIZE; \
769 if (size <= old_size || !size) { \
772 state->COUNT = slot * SIZE; \
773 if (!size && old_size) { \
774 kfree(state->FIELD); \
775 state->FIELD = NULL; \
779 new_##FIELD = kmalloc_array(slot, sizeof(struct bpf_##NAME##_state), \
785 memcpy(new_##FIELD, state->FIELD, \
786 sizeof(*new_##FIELD) * (old_size / SIZE)); \
787 memset(new_##FIELD + old_size / SIZE, 0, \
788 sizeof(*new_##FIELD) * (size - old_size) / SIZE); \
790 state->COUNT = slot * SIZE; \
791 kfree(state->FIELD); \
792 state->FIELD = new_##FIELD; \
795 /* realloc_reference_state() */
796 REALLOC_STATE_FN(reference
, acquired_refs
, refs
, 1)
797 /* realloc_stack_state() */
798 REALLOC_STATE_FN(stack
, allocated_stack
, stack
, BPF_REG_SIZE
)
799 #undef REALLOC_STATE_FN
801 /* do_check() starts with zero-sized stack in struct bpf_verifier_state to
802 * make it consume minimal amount of memory. check_stack_write() access from
803 * the program calls into realloc_func_state() to grow the stack size.
804 * Note there is a non-zero 'parent' pointer inside bpf_verifier_state
805 * which realloc_stack_state() copies over. It points to previous
806 * bpf_verifier_state which is never reallocated.
808 static int realloc_func_state(struct bpf_func_state
*state
, int stack_size
,
809 int refs_size
, bool copy_old
)
811 int err
= realloc_reference_state(state
, refs_size
, copy_old
);
814 return realloc_stack_state(state
, stack_size
, copy_old
);
817 /* Acquire a pointer id from the env and update the state->refs to include
818 * this new pointer reference.
819 * On success, returns a valid pointer id to associate with the register
820 * On failure, returns a negative errno.
822 static int acquire_reference_state(struct bpf_verifier_env
*env
, int insn_idx
)
824 struct bpf_func_state
*state
= cur_func(env
);
825 int new_ofs
= state
->acquired_refs
;
828 err
= realloc_reference_state(state
, state
->acquired_refs
+ 1, true);
832 state
->refs
[new_ofs
].id
= id
;
833 state
->refs
[new_ofs
].insn_idx
= insn_idx
;
838 /* release function corresponding to acquire_reference_state(). Idempotent. */
839 static int release_reference_state(struct bpf_func_state
*state
, int ptr_id
)
843 last_idx
= state
->acquired_refs
- 1;
844 for (i
= 0; i
< state
->acquired_refs
; i
++) {
845 if (state
->refs
[i
].id
== ptr_id
) {
846 if (last_idx
&& i
!= last_idx
)
847 memcpy(&state
->refs
[i
], &state
->refs
[last_idx
],
848 sizeof(*state
->refs
));
849 memset(&state
->refs
[last_idx
], 0, sizeof(*state
->refs
));
850 state
->acquired_refs
--;
857 static int transfer_reference_state(struct bpf_func_state
*dst
,
858 struct bpf_func_state
*src
)
860 int err
= realloc_reference_state(dst
, src
->acquired_refs
, false);
863 err
= copy_reference_state(dst
, src
);
869 static void free_func_state(struct bpf_func_state
*state
)
878 static void clear_jmp_history(struct bpf_verifier_state
*state
)
880 kfree(state
->jmp_history
);
881 state
->jmp_history
= NULL
;
882 state
->jmp_history_cnt
= 0;
885 static void free_verifier_state(struct bpf_verifier_state
*state
,
890 for (i
= 0; i
<= state
->curframe
; i
++) {
891 free_func_state(state
->frame
[i
]);
892 state
->frame
[i
] = NULL
;
894 clear_jmp_history(state
);
899 /* copy verifier state from src to dst growing dst stack space
900 * when necessary to accommodate larger src stack
902 static int copy_func_state(struct bpf_func_state
*dst
,
903 const struct bpf_func_state
*src
)
907 err
= realloc_func_state(dst
, src
->allocated_stack
, src
->acquired_refs
,
911 memcpy(dst
, src
, offsetof(struct bpf_func_state
, acquired_refs
));
912 err
= copy_reference_state(dst
, src
);
915 return copy_stack_state(dst
, src
);
918 static int copy_verifier_state(struct bpf_verifier_state
*dst_state
,
919 const struct bpf_verifier_state
*src
)
921 struct bpf_func_state
*dst
;
922 u32 jmp_sz
= sizeof(struct bpf_idx_pair
) * src
->jmp_history_cnt
;
925 if (dst_state
->jmp_history_cnt
< src
->jmp_history_cnt
) {
926 kfree(dst_state
->jmp_history
);
927 dst_state
->jmp_history
= kmalloc(jmp_sz
, GFP_USER
);
928 if (!dst_state
->jmp_history
)
931 memcpy(dst_state
->jmp_history
, src
->jmp_history
, jmp_sz
);
932 dst_state
->jmp_history_cnt
= src
->jmp_history_cnt
;
934 /* if dst has more stack frames then src frame, free them */
935 for (i
= src
->curframe
+ 1; i
<= dst_state
->curframe
; i
++) {
936 free_func_state(dst_state
->frame
[i
]);
937 dst_state
->frame
[i
] = NULL
;
939 dst_state
->speculative
= src
->speculative
;
940 dst_state
->curframe
= src
->curframe
;
941 dst_state
->active_spin_lock
= src
->active_spin_lock
;
942 dst_state
->branches
= src
->branches
;
943 dst_state
->parent
= src
->parent
;
944 dst_state
->first_insn_idx
= src
->first_insn_idx
;
945 dst_state
->last_insn_idx
= src
->last_insn_idx
;
946 for (i
= 0; i
<= src
->curframe
; i
++) {
947 dst
= dst_state
->frame
[i
];
949 dst
= kzalloc(sizeof(*dst
), GFP_KERNEL
);
952 dst_state
->frame
[i
] = dst
;
954 err
= copy_func_state(dst
, src
->frame
[i
]);
961 static void update_branch_counts(struct bpf_verifier_env
*env
, struct bpf_verifier_state
*st
)
964 u32 br
= --st
->branches
;
966 /* WARN_ON(br > 1) technically makes sense here,
967 * but see comment in push_stack(), hence:
969 WARN_ONCE((int)br
< 0,
970 "BUG update_branch_counts:branches_to_explore=%d\n",
978 static int pop_stack(struct bpf_verifier_env
*env
, int *prev_insn_idx
,
979 int *insn_idx
, bool pop_log
)
981 struct bpf_verifier_state
*cur
= env
->cur_state
;
982 struct bpf_verifier_stack_elem
*elem
, *head
= env
->head
;
985 if (env
->head
== NULL
)
989 err
= copy_verifier_state(cur
, &head
->st
);
994 bpf_vlog_reset(&env
->log
, head
->log_pos
);
996 *insn_idx
= head
->insn_idx
;
998 *prev_insn_idx
= head
->prev_insn_idx
;
1000 free_verifier_state(&head
->st
, false);
1007 static struct bpf_verifier_state
*push_stack(struct bpf_verifier_env
*env
,
1008 int insn_idx
, int prev_insn_idx
,
1011 struct bpf_verifier_state
*cur
= env
->cur_state
;
1012 struct bpf_verifier_stack_elem
*elem
;
1015 elem
= kzalloc(sizeof(struct bpf_verifier_stack_elem
), GFP_KERNEL
);
1019 elem
->insn_idx
= insn_idx
;
1020 elem
->prev_insn_idx
= prev_insn_idx
;
1021 elem
->next
= env
->head
;
1022 elem
->log_pos
= env
->log
.len_used
;
1025 err
= copy_verifier_state(&elem
->st
, cur
);
1028 elem
->st
.speculative
|= speculative
;
1029 if (env
->stack_size
> BPF_COMPLEXITY_LIMIT_JMP_SEQ
) {
1030 verbose(env
, "The sequence of %d jumps is too complex.\n",
1034 if (elem
->st
.parent
) {
1035 ++elem
->st
.parent
->branches
;
1036 /* WARN_ON(branches > 2) technically makes sense here,
1038 * 1. speculative states will bump 'branches' for non-branch
1040 * 2. is_state_visited() heuristics may decide not to create
1041 * a new state for a sequence of branches and all such current
1042 * and cloned states will be pointing to a single parent state
1043 * which might have large 'branches' count.
1048 free_verifier_state(env
->cur_state
, true);
1049 env
->cur_state
= NULL
;
1050 /* pop all elements and return */
1051 while (!pop_stack(env
, NULL
, NULL
, false));
1055 #define CALLER_SAVED_REGS 6
1056 static const int caller_saved
[CALLER_SAVED_REGS
] = {
1057 BPF_REG_0
, BPF_REG_1
, BPF_REG_2
, BPF_REG_3
, BPF_REG_4
, BPF_REG_5
1060 static void __mark_reg_not_init(const struct bpf_verifier_env
*env
,
1061 struct bpf_reg_state
*reg
);
1063 /* This helper doesn't clear reg->id */
1064 static void ___mark_reg_known(struct bpf_reg_state
*reg
, u64 imm
)
1066 reg
->var_off
= tnum_const(imm
);
1067 reg
->smin_value
= (s64
)imm
;
1068 reg
->smax_value
= (s64
)imm
;
1069 reg
->umin_value
= imm
;
1070 reg
->umax_value
= imm
;
1072 reg
->s32_min_value
= (s32
)imm
;
1073 reg
->s32_max_value
= (s32
)imm
;
1074 reg
->u32_min_value
= (u32
)imm
;
1075 reg
->u32_max_value
= (u32
)imm
;
1078 /* Mark the unknown part of a register (variable offset or scalar value) as
1079 * known to have the value @imm.
1081 static void __mark_reg_known(struct bpf_reg_state
*reg
, u64 imm
)
1083 /* Clear id, off, and union(map_ptr, range) */
1084 memset(((u8
*)reg
) + sizeof(reg
->type
), 0,
1085 offsetof(struct bpf_reg_state
, var_off
) - sizeof(reg
->type
));
1086 ___mark_reg_known(reg
, imm
);
1089 static void __mark_reg32_known(struct bpf_reg_state
*reg
, u64 imm
)
1091 reg
->var_off
= tnum_const_subreg(reg
->var_off
, imm
);
1092 reg
->s32_min_value
= (s32
)imm
;
1093 reg
->s32_max_value
= (s32
)imm
;
1094 reg
->u32_min_value
= (u32
)imm
;
1095 reg
->u32_max_value
= (u32
)imm
;
1098 /* Mark the 'variable offset' part of a register as zero. This should be
1099 * used only on registers holding a pointer type.
1101 static void __mark_reg_known_zero(struct bpf_reg_state
*reg
)
1103 __mark_reg_known(reg
, 0);
1106 static void __mark_reg_const_zero(struct bpf_reg_state
*reg
)
1108 __mark_reg_known(reg
, 0);
1109 reg
->type
= SCALAR_VALUE
;
1112 static void mark_reg_known_zero(struct bpf_verifier_env
*env
,
1113 struct bpf_reg_state
*regs
, u32 regno
)
1115 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
1116 verbose(env
, "mark_reg_known_zero(regs, %u)\n", regno
);
1117 /* Something bad happened, let's kill all regs */
1118 for (regno
= 0; regno
< MAX_BPF_REG
; regno
++)
1119 __mark_reg_not_init(env
, regs
+ regno
);
1122 __mark_reg_known_zero(regs
+ regno
);
1125 static void mark_ptr_not_null_reg(struct bpf_reg_state
*reg
)
1127 switch (reg
->type
) {
1128 case PTR_TO_MAP_VALUE_OR_NULL
: {
1129 const struct bpf_map
*map
= reg
->map_ptr
;
1131 if (map
->inner_map_meta
) {
1132 reg
->type
= CONST_PTR_TO_MAP
;
1133 reg
->map_ptr
= map
->inner_map_meta
;
1134 } else if (map
->map_type
== BPF_MAP_TYPE_XSKMAP
) {
1135 reg
->type
= PTR_TO_XDP_SOCK
;
1136 } else if (map
->map_type
== BPF_MAP_TYPE_SOCKMAP
||
1137 map
->map_type
== BPF_MAP_TYPE_SOCKHASH
) {
1138 reg
->type
= PTR_TO_SOCKET
;
1140 reg
->type
= PTR_TO_MAP_VALUE
;
1144 case PTR_TO_SOCKET_OR_NULL
:
1145 reg
->type
= PTR_TO_SOCKET
;
1147 case PTR_TO_SOCK_COMMON_OR_NULL
:
1148 reg
->type
= PTR_TO_SOCK_COMMON
;
1150 case PTR_TO_TCP_SOCK_OR_NULL
:
1151 reg
->type
= PTR_TO_TCP_SOCK
;
1153 case PTR_TO_BTF_ID_OR_NULL
:
1154 reg
->type
= PTR_TO_BTF_ID
;
1156 case PTR_TO_MEM_OR_NULL
:
1157 reg
->type
= PTR_TO_MEM
;
1159 case PTR_TO_RDONLY_BUF_OR_NULL
:
1160 reg
->type
= PTR_TO_RDONLY_BUF
;
1162 case PTR_TO_RDWR_BUF_OR_NULL
:
1163 reg
->type
= PTR_TO_RDWR_BUF
;
1166 WARN_ONCE(1, "unknown nullable register type");
1170 static bool reg_is_pkt_pointer(const struct bpf_reg_state
*reg
)
1172 return type_is_pkt_pointer(reg
->type
);
1175 static bool reg_is_pkt_pointer_any(const struct bpf_reg_state
*reg
)
1177 return reg_is_pkt_pointer(reg
) ||
1178 reg
->type
== PTR_TO_PACKET_END
;
1181 /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
1182 static bool reg_is_init_pkt_pointer(const struct bpf_reg_state
*reg
,
1183 enum bpf_reg_type which
)
1185 /* The register can already have a range from prior markings.
1186 * This is fine as long as it hasn't been advanced from its
1189 return reg
->type
== which
&&
1192 tnum_equals_const(reg
->var_off
, 0);
1195 /* Reset the min/max bounds of a register */
1196 static void __mark_reg_unbounded(struct bpf_reg_state
*reg
)
1198 reg
->smin_value
= S64_MIN
;
1199 reg
->smax_value
= S64_MAX
;
1200 reg
->umin_value
= 0;
1201 reg
->umax_value
= U64_MAX
;
1203 reg
->s32_min_value
= S32_MIN
;
1204 reg
->s32_max_value
= S32_MAX
;
1205 reg
->u32_min_value
= 0;
1206 reg
->u32_max_value
= U32_MAX
;
1209 static void __mark_reg64_unbounded(struct bpf_reg_state
*reg
)
1211 reg
->smin_value
= S64_MIN
;
1212 reg
->smax_value
= S64_MAX
;
1213 reg
->umin_value
= 0;
1214 reg
->umax_value
= U64_MAX
;
1217 static void __mark_reg32_unbounded(struct bpf_reg_state
*reg
)
1219 reg
->s32_min_value
= S32_MIN
;
1220 reg
->s32_max_value
= S32_MAX
;
1221 reg
->u32_min_value
= 0;
1222 reg
->u32_max_value
= U32_MAX
;
1225 static void __update_reg32_bounds(struct bpf_reg_state
*reg
)
1227 struct tnum var32_off
= tnum_subreg(reg
->var_off
);
1229 /* min signed is max(sign bit) | min(other bits) */
1230 reg
->s32_min_value
= max_t(s32
, reg
->s32_min_value
,
1231 var32_off
.value
| (var32_off
.mask
& S32_MIN
));
1232 /* max signed is min(sign bit) | max(other bits) */
1233 reg
->s32_max_value
= min_t(s32
, reg
->s32_max_value
,
1234 var32_off
.value
| (var32_off
.mask
& S32_MAX
));
1235 reg
->u32_min_value
= max_t(u32
, reg
->u32_min_value
, (u32
)var32_off
.value
);
1236 reg
->u32_max_value
= min(reg
->u32_max_value
,
1237 (u32
)(var32_off
.value
| var32_off
.mask
));
1240 static void __update_reg64_bounds(struct bpf_reg_state
*reg
)
1242 /* min signed is max(sign bit) | min(other bits) */
1243 reg
->smin_value
= max_t(s64
, reg
->smin_value
,
1244 reg
->var_off
.value
| (reg
->var_off
.mask
& S64_MIN
));
1245 /* max signed is min(sign bit) | max(other bits) */
1246 reg
->smax_value
= min_t(s64
, reg
->smax_value
,
1247 reg
->var_off
.value
| (reg
->var_off
.mask
& S64_MAX
));
1248 reg
->umin_value
= max(reg
->umin_value
, reg
->var_off
.value
);
1249 reg
->umax_value
= min(reg
->umax_value
,
1250 reg
->var_off
.value
| reg
->var_off
.mask
);
1253 static void __update_reg_bounds(struct bpf_reg_state
*reg
)
1255 __update_reg32_bounds(reg
);
1256 __update_reg64_bounds(reg
);
1259 /* Uses signed min/max values to inform unsigned, and vice-versa */
1260 static void __reg32_deduce_bounds(struct bpf_reg_state
*reg
)
1262 /* Learn sign from signed bounds.
1263 * If we cannot cross the sign boundary, then signed and unsigned bounds
1264 * are the same, so combine. This works even in the negative case, e.g.
1265 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
1267 if (reg
->s32_min_value
>= 0 || reg
->s32_max_value
< 0) {
1268 reg
->s32_min_value
= reg
->u32_min_value
=
1269 max_t(u32
, reg
->s32_min_value
, reg
->u32_min_value
);
1270 reg
->s32_max_value
= reg
->u32_max_value
=
1271 min_t(u32
, reg
->s32_max_value
, reg
->u32_max_value
);
1274 /* Learn sign from unsigned bounds. Signed bounds cross the sign
1275 * boundary, so we must be careful.
1277 if ((s32
)reg
->u32_max_value
>= 0) {
1278 /* Positive. We can't learn anything from the smin, but smax
1279 * is positive, hence safe.
1281 reg
->s32_min_value
= reg
->u32_min_value
;
1282 reg
->s32_max_value
= reg
->u32_max_value
=
1283 min_t(u32
, reg
->s32_max_value
, reg
->u32_max_value
);
1284 } else if ((s32
)reg
->u32_min_value
< 0) {
1285 /* Negative. We can't learn anything from the smax, but smin
1286 * is negative, hence safe.
1288 reg
->s32_min_value
= reg
->u32_min_value
=
1289 max_t(u32
, reg
->s32_min_value
, reg
->u32_min_value
);
1290 reg
->s32_max_value
= reg
->u32_max_value
;
1294 static void __reg64_deduce_bounds(struct bpf_reg_state
*reg
)
1296 /* Learn sign from signed bounds.
1297 * If we cannot cross the sign boundary, then signed and unsigned bounds
1298 * are the same, so combine. This works even in the negative case, e.g.
1299 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
1301 if (reg
->smin_value
>= 0 || reg
->smax_value
< 0) {
1302 reg
->smin_value
= reg
->umin_value
= max_t(u64
, reg
->smin_value
,
1304 reg
->smax_value
= reg
->umax_value
= min_t(u64
, reg
->smax_value
,
1308 /* Learn sign from unsigned bounds. Signed bounds cross the sign
1309 * boundary, so we must be careful.
1311 if ((s64
)reg
->umax_value
>= 0) {
1312 /* Positive. We can't learn anything from the smin, but smax
1313 * is positive, hence safe.
1315 reg
->smin_value
= reg
->umin_value
;
1316 reg
->smax_value
= reg
->umax_value
= min_t(u64
, reg
->smax_value
,
1318 } else if ((s64
)reg
->umin_value
< 0) {
1319 /* Negative. We can't learn anything from the smax, but smin
1320 * is negative, hence safe.
1322 reg
->smin_value
= reg
->umin_value
= max_t(u64
, reg
->smin_value
,
1324 reg
->smax_value
= reg
->umax_value
;
1328 static void __reg_deduce_bounds(struct bpf_reg_state
*reg
)
1330 __reg32_deduce_bounds(reg
);
1331 __reg64_deduce_bounds(reg
);
1334 /* Attempts to improve var_off based on unsigned min/max information */
1335 static void __reg_bound_offset(struct bpf_reg_state
*reg
)
1337 struct tnum var64_off
= tnum_intersect(reg
->var_off
,
1338 tnum_range(reg
->umin_value
,
1340 struct tnum var32_off
= tnum_intersect(tnum_subreg(reg
->var_off
),
1341 tnum_range(reg
->u32_min_value
,
1342 reg
->u32_max_value
));
1344 reg
->var_off
= tnum_or(tnum_clear_subreg(var64_off
), var32_off
);
1347 static void __reg_assign_32_into_64(struct bpf_reg_state
*reg
)
1349 reg
->umin_value
= reg
->u32_min_value
;
1350 reg
->umax_value
= reg
->u32_max_value
;
1351 /* Attempt to pull 32-bit signed bounds into 64-bit bounds
1352 * but must be positive otherwise set to worse case bounds
1353 * and refine later from tnum.
1355 if (reg
->s32_min_value
>= 0 && reg
->s32_max_value
>= 0)
1356 reg
->smax_value
= reg
->s32_max_value
;
1358 reg
->smax_value
= U32_MAX
;
1359 if (reg
->s32_min_value
>= 0)
1360 reg
->smin_value
= reg
->s32_min_value
;
1362 reg
->smin_value
= 0;
1365 static void __reg_combine_32_into_64(struct bpf_reg_state
*reg
)
1367 /* special case when 64-bit register has upper 32-bit register
1368 * zeroed. Typically happens after zext or <<32, >>32 sequence
1369 * allowing us to use 32-bit bounds directly,
1371 if (tnum_equals_const(tnum_clear_subreg(reg
->var_off
), 0)) {
1372 __reg_assign_32_into_64(reg
);
1374 /* Otherwise the best we can do is push lower 32bit known and
1375 * unknown bits into register (var_off set from jmp logic)
1376 * then learn as much as possible from the 64-bit tnum
1377 * known and unknown bits. The previous smin/smax bounds are
1378 * invalid here because of jmp32 compare so mark them unknown
1379 * so they do not impact tnum bounds calculation.
1381 __mark_reg64_unbounded(reg
);
1382 __update_reg_bounds(reg
);
1385 /* Intersecting with the old var_off might have improved our bounds
1386 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
1387 * then new var_off is (0; 0x7f...fc) which improves our umax.
1389 __reg_deduce_bounds(reg
);
1390 __reg_bound_offset(reg
);
1391 __update_reg_bounds(reg
);
1394 static bool __reg64_bound_s32(s64 a
)
1396 return a
> S32_MIN
&& a
< S32_MAX
;
1399 static bool __reg64_bound_u32(u64 a
)
1401 return a
> U32_MIN
&& a
< U32_MAX
;
1404 static void __reg_combine_64_into_32(struct bpf_reg_state
*reg
)
1406 __mark_reg32_unbounded(reg
);
1408 if (__reg64_bound_s32(reg
->smin_value
) && __reg64_bound_s32(reg
->smax_value
)) {
1409 reg
->s32_min_value
= (s32
)reg
->smin_value
;
1410 reg
->s32_max_value
= (s32
)reg
->smax_value
;
1412 if (__reg64_bound_u32(reg
->umin_value
) && __reg64_bound_u32(reg
->umax_value
)) {
1413 reg
->u32_min_value
= (u32
)reg
->umin_value
;
1414 reg
->u32_max_value
= (u32
)reg
->umax_value
;
1417 /* Intersecting with the old var_off might have improved our bounds
1418 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
1419 * then new var_off is (0; 0x7f...fc) which improves our umax.
1421 __reg_deduce_bounds(reg
);
1422 __reg_bound_offset(reg
);
1423 __update_reg_bounds(reg
);
1426 /* Mark a register as having a completely unknown (scalar) value. */
1427 static void __mark_reg_unknown(const struct bpf_verifier_env
*env
,
1428 struct bpf_reg_state
*reg
)
1431 * Clear type, id, off, and union(map_ptr, range) and
1432 * padding between 'type' and union
1434 memset(reg
, 0, offsetof(struct bpf_reg_state
, var_off
));
1435 reg
->type
= SCALAR_VALUE
;
1436 reg
->var_off
= tnum_unknown
;
1438 reg
->precise
= env
->subprog_cnt
> 1 || !env
->bpf_capable
;
1439 __mark_reg_unbounded(reg
);
1442 static void mark_reg_unknown(struct bpf_verifier_env
*env
,
1443 struct bpf_reg_state
*regs
, u32 regno
)
1445 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
1446 verbose(env
, "mark_reg_unknown(regs, %u)\n", regno
);
1447 /* Something bad happened, let's kill all regs except FP */
1448 for (regno
= 0; regno
< BPF_REG_FP
; regno
++)
1449 __mark_reg_not_init(env
, regs
+ regno
);
1452 __mark_reg_unknown(env
, regs
+ regno
);
1455 static void __mark_reg_not_init(const struct bpf_verifier_env
*env
,
1456 struct bpf_reg_state
*reg
)
1458 __mark_reg_unknown(env
, reg
);
1459 reg
->type
= NOT_INIT
;
1462 static void mark_reg_not_init(struct bpf_verifier_env
*env
,
1463 struct bpf_reg_state
*regs
, u32 regno
)
1465 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
1466 verbose(env
, "mark_reg_not_init(regs, %u)\n", regno
);
1467 /* Something bad happened, let's kill all regs except FP */
1468 for (regno
= 0; regno
< BPF_REG_FP
; regno
++)
1469 __mark_reg_not_init(env
, regs
+ regno
);
1472 __mark_reg_not_init(env
, regs
+ regno
);
1475 static void mark_btf_ld_reg(struct bpf_verifier_env
*env
,
1476 struct bpf_reg_state
*regs
, u32 regno
,
1477 enum bpf_reg_type reg_type
,
1478 struct btf
*btf
, u32 btf_id
)
1480 if (reg_type
== SCALAR_VALUE
) {
1481 mark_reg_unknown(env
, regs
, regno
);
1484 mark_reg_known_zero(env
, regs
, regno
);
1485 regs
[regno
].type
= PTR_TO_BTF_ID
;
1486 regs
[regno
].btf
= btf
;
1487 regs
[regno
].btf_id
= btf_id
;
1490 #define DEF_NOT_SUBREG (0)
1491 static void init_reg_state(struct bpf_verifier_env
*env
,
1492 struct bpf_func_state
*state
)
1494 struct bpf_reg_state
*regs
= state
->regs
;
1497 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
1498 mark_reg_not_init(env
, regs
, i
);
1499 regs
[i
].live
= REG_LIVE_NONE
;
1500 regs
[i
].parent
= NULL
;
1501 regs
[i
].subreg_def
= DEF_NOT_SUBREG
;
1505 regs
[BPF_REG_FP
].type
= PTR_TO_STACK
;
1506 mark_reg_known_zero(env
, regs
, BPF_REG_FP
);
1507 regs
[BPF_REG_FP
].frameno
= state
->frameno
;
1510 #define BPF_MAIN_FUNC (-1)
1511 static void init_func_state(struct bpf_verifier_env
*env
,
1512 struct bpf_func_state
*state
,
1513 int callsite
, int frameno
, int subprogno
)
1515 state
->callsite
= callsite
;
1516 state
->frameno
= frameno
;
1517 state
->subprogno
= subprogno
;
1518 init_reg_state(env
, state
);
1522 SRC_OP
, /* register is used as source operand */
1523 DST_OP
, /* register is used as destination operand */
1524 DST_OP_NO_MARK
/* same as above, check only, don't mark */
1527 static int cmp_subprogs(const void *a
, const void *b
)
1529 return ((struct bpf_subprog_info
*)a
)->start
-
1530 ((struct bpf_subprog_info
*)b
)->start
;
1533 static int find_subprog(struct bpf_verifier_env
*env
, int off
)
1535 struct bpf_subprog_info
*p
;
1537 p
= bsearch(&off
, env
->subprog_info
, env
->subprog_cnt
,
1538 sizeof(env
->subprog_info
[0]), cmp_subprogs
);
1541 return p
- env
->subprog_info
;
1545 static int add_subprog(struct bpf_verifier_env
*env
, int off
)
1547 int insn_cnt
= env
->prog
->len
;
1550 if (off
>= insn_cnt
|| off
< 0) {
1551 verbose(env
, "call to invalid destination\n");
1554 ret
= find_subprog(env
, off
);
1557 if (env
->subprog_cnt
>= BPF_MAX_SUBPROGS
) {
1558 verbose(env
, "too many subprograms\n");
1561 /* determine subprog starts. The end is one before the next starts */
1562 env
->subprog_info
[env
->subprog_cnt
++].start
= off
;
1563 sort(env
->subprog_info
, env
->subprog_cnt
,
1564 sizeof(env
->subprog_info
[0]), cmp_subprogs
, NULL
);
1565 return env
->subprog_cnt
- 1;
1568 struct bpf_kfunc_desc
{
1569 struct btf_func_model func_model
;
1574 #define MAX_KFUNC_DESCS 256
1575 struct bpf_kfunc_desc_tab
{
1576 struct bpf_kfunc_desc descs
[MAX_KFUNC_DESCS
];
1580 static int kfunc_desc_cmp_by_id(const void *a
, const void *b
)
1582 const struct bpf_kfunc_desc
*d0
= a
;
1583 const struct bpf_kfunc_desc
*d1
= b
;
1585 /* func_id is not greater than BTF_MAX_TYPE */
1586 return d0
->func_id
- d1
->func_id
;
1589 static const struct bpf_kfunc_desc
*
1590 find_kfunc_desc(const struct bpf_prog
*prog
, u32 func_id
)
1592 struct bpf_kfunc_desc desc
= {
1595 struct bpf_kfunc_desc_tab
*tab
;
1597 tab
= prog
->aux
->kfunc_tab
;
1598 return bsearch(&desc
, tab
->descs
, tab
->nr_descs
,
1599 sizeof(tab
->descs
[0]), kfunc_desc_cmp_by_id
);
1602 static int add_kfunc_call(struct bpf_verifier_env
*env
, u32 func_id
)
1604 const struct btf_type
*func
, *func_proto
;
1605 struct bpf_kfunc_desc_tab
*tab
;
1606 struct bpf_prog_aux
*prog_aux
;
1607 struct bpf_kfunc_desc
*desc
;
1608 const char *func_name
;
1612 prog_aux
= env
->prog
->aux
;
1613 tab
= prog_aux
->kfunc_tab
;
1616 verbose(env
, "calling kernel function is not supported without CONFIG_DEBUG_INFO_BTF\n");
1620 if (!env
->prog
->jit_requested
) {
1621 verbose(env
, "JIT is required for calling kernel function\n");
1625 if (!bpf_jit_supports_kfunc_call()) {
1626 verbose(env
, "JIT does not support calling kernel function\n");
1630 if (!env
->prog
->gpl_compatible
) {
1631 verbose(env
, "cannot call kernel function from non-GPL compatible program\n");
1635 tab
= kzalloc(sizeof(*tab
), GFP_KERNEL
);
1638 prog_aux
->kfunc_tab
= tab
;
1641 if (find_kfunc_desc(env
->prog
, func_id
))
1644 if (tab
->nr_descs
== MAX_KFUNC_DESCS
) {
1645 verbose(env
, "too many different kernel function calls\n");
1649 func
= btf_type_by_id(btf_vmlinux
, func_id
);
1650 if (!func
|| !btf_type_is_func(func
)) {
1651 verbose(env
, "kernel btf_id %u is not a function\n",
1655 func_proto
= btf_type_by_id(btf_vmlinux
, func
->type
);
1656 if (!func_proto
|| !btf_type_is_func_proto(func_proto
)) {
1657 verbose(env
, "kernel function btf_id %u does not have a valid func_proto\n",
1662 func_name
= btf_name_by_offset(btf_vmlinux
, func
->name_off
);
1663 addr
= kallsyms_lookup_name(func_name
);
1665 verbose(env
, "cannot find address for kernel function %s\n",
1670 desc
= &tab
->descs
[tab
->nr_descs
++];
1671 desc
->func_id
= func_id
;
1672 desc
->imm
= BPF_CAST_CALL(addr
) - __bpf_call_base
;
1673 err
= btf_distill_func_proto(&env
->log
, btf_vmlinux
,
1674 func_proto
, func_name
,
1677 sort(tab
->descs
, tab
->nr_descs
, sizeof(tab
->descs
[0]),
1678 kfunc_desc_cmp_by_id
, NULL
);
1682 static int kfunc_desc_cmp_by_imm(const void *a
, const void *b
)
1684 const struct bpf_kfunc_desc
*d0
= a
;
1685 const struct bpf_kfunc_desc
*d1
= b
;
1687 if (d0
->imm
> d1
->imm
)
1689 else if (d0
->imm
< d1
->imm
)
1694 static void sort_kfunc_descs_by_imm(struct bpf_prog
*prog
)
1696 struct bpf_kfunc_desc_tab
*tab
;
1698 tab
= prog
->aux
->kfunc_tab
;
1702 sort(tab
->descs
, tab
->nr_descs
, sizeof(tab
->descs
[0]),
1703 kfunc_desc_cmp_by_imm
, NULL
);
1706 bool bpf_prog_has_kfunc_call(const struct bpf_prog
*prog
)
1708 return !!prog
->aux
->kfunc_tab
;
1711 const struct btf_func_model
*
1712 bpf_jit_find_kfunc_model(const struct bpf_prog
*prog
,
1713 const struct bpf_insn
*insn
)
1715 const struct bpf_kfunc_desc desc
= {
1718 const struct bpf_kfunc_desc
*res
;
1719 struct bpf_kfunc_desc_tab
*tab
;
1721 tab
= prog
->aux
->kfunc_tab
;
1722 res
= bsearch(&desc
, tab
->descs
, tab
->nr_descs
,
1723 sizeof(tab
->descs
[0]), kfunc_desc_cmp_by_imm
);
1725 return res
? &res
->func_model
: NULL
;
1728 static int add_subprog_and_kfunc(struct bpf_verifier_env
*env
)
1730 struct bpf_subprog_info
*subprog
= env
->subprog_info
;
1731 struct bpf_insn
*insn
= env
->prog
->insnsi
;
1732 int i
, ret
, insn_cnt
= env
->prog
->len
;
1734 /* Add entry function. */
1735 ret
= add_subprog(env
, 0);
1739 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
1740 if (!bpf_pseudo_func(insn
) && !bpf_pseudo_call(insn
) &&
1741 !bpf_pseudo_kfunc_call(insn
))
1744 if (!env
->bpf_capable
) {
1745 verbose(env
, "loading/calling other bpf or kernel functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n");
1749 if (bpf_pseudo_func(insn
)) {
1750 ret
= add_subprog(env
, i
+ insn
->imm
+ 1);
1752 /* remember subprog */
1754 } else if (bpf_pseudo_call(insn
)) {
1755 ret
= add_subprog(env
, i
+ insn
->imm
+ 1);
1757 ret
= add_kfunc_call(env
, insn
->imm
);
1764 /* Add a fake 'exit' subprog which could simplify subprog iteration
1765 * logic. 'subprog_cnt' should not be increased.
1767 subprog
[env
->subprog_cnt
].start
= insn_cnt
;
1769 if (env
->log
.level
& BPF_LOG_LEVEL2
)
1770 for (i
= 0; i
< env
->subprog_cnt
; i
++)
1771 verbose(env
, "func#%d @%d\n", i
, subprog
[i
].start
);
1776 static int check_subprogs(struct bpf_verifier_env
*env
)
1778 int i
, subprog_start
, subprog_end
, off
, cur_subprog
= 0;
1779 struct bpf_subprog_info
*subprog
= env
->subprog_info
;
1780 struct bpf_insn
*insn
= env
->prog
->insnsi
;
1781 int insn_cnt
= env
->prog
->len
;
1783 /* now check that all jumps are within the same subprog */
1784 subprog_start
= subprog
[cur_subprog
].start
;
1785 subprog_end
= subprog
[cur_subprog
+ 1].start
;
1786 for (i
= 0; i
< insn_cnt
; i
++) {
1787 u8 code
= insn
[i
].code
;
1789 if (code
== (BPF_JMP
| BPF_CALL
) &&
1790 insn
[i
].imm
== BPF_FUNC_tail_call
&&
1791 insn
[i
].src_reg
!= BPF_PSEUDO_CALL
)
1792 subprog
[cur_subprog
].has_tail_call
= true;
1793 if (BPF_CLASS(code
) == BPF_LD
&&
1794 (BPF_MODE(code
) == BPF_ABS
|| BPF_MODE(code
) == BPF_IND
))
1795 subprog
[cur_subprog
].has_ld_abs
= true;
1796 if (BPF_CLASS(code
) != BPF_JMP
&& BPF_CLASS(code
) != BPF_JMP32
)
1798 if (BPF_OP(code
) == BPF_EXIT
|| BPF_OP(code
) == BPF_CALL
)
1800 off
= i
+ insn
[i
].off
+ 1;
1801 if (off
< subprog_start
|| off
>= subprog_end
) {
1802 verbose(env
, "jump out of range from insn %d to %d\n", i
, off
);
1806 if (i
== subprog_end
- 1) {
1807 /* to avoid fall-through from one subprog into another
1808 * the last insn of the subprog should be either exit
1809 * or unconditional jump back
1811 if (code
!= (BPF_JMP
| BPF_EXIT
) &&
1812 code
!= (BPF_JMP
| BPF_JA
)) {
1813 verbose(env
, "last insn is not an exit or jmp\n");
1816 subprog_start
= subprog_end
;
1818 if (cur_subprog
< env
->subprog_cnt
)
1819 subprog_end
= subprog
[cur_subprog
+ 1].start
;
1825 /* Parentage chain of this register (or stack slot) should take care of all
1826 * issues like callee-saved registers, stack slot allocation time, etc.
1828 static int mark_reg_read(struct bpf_verifier_env
*env
,
1829 const struct bpf_reg_state
*state
,
1830 struct bpf_reg_state
*parent
, u8 flag
)
1832 bool writes
= parent
== state
->parent
; /* Observe write marks */
1836 /* if read wasn't screened by an earlier write ... */
1837 if (writes
&& state
->live
& REG_LIVE_WRITTEN
)
1839 if (parent
->live
& REG_LIVE_DONE
) {
1840 verbose(env
, "verifier BUG type %s var_off %lld off %d\n",
1841 reg_type_str
[parent
->type
],
1842 parent
->var_off
.value
, parent
->off
);
1845 /* The first condition is more likely to be true than the
1846 * second, checked it first.
1848 if ((parent
->live
& REG_LIVE_READ
) == flag
||
1849 parent
->live
& REG_LIVE_READ64
)
1850 /* The parentage chain never changes and
1851 * this parent was already marked as LIVE_READ.
1852 * There is no need to keep walking the chain again and
1853 * keep re-marking all parents as LIVE_READ.
1854 * This case happens when the same register is read
1855 * multiple times without writes into it in-between.
1856 * Also, if parent has the stronger REG_LIVE_READ64 set,
1857 * then no need to set the weak REG_LIVE_READ32.
1860 /* ... then we depend on parent's value */
1861 parent
->live
|= flag
;
1862 /* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
1863 if (flag
== REG_LIVE_READ64
)
1864 parent
->live
&= ~REG_LIVE_READ32
;
1866 parent
= state
->parent
;
1871 if (env
->longest_mark_read_walk
< cnt
)
1872 env
->longest_mark_read_walk
= cnt
;
1876 /* This function is supposed to be used by the following 32-bit optimization
1877 * code only. It returns TRUE if the source or destination register operates
1878 * on 64-bit, otherwise return FALSE.
1880 static bool is_reg64(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
,
1881 u32 regno
, struct bpf_reg_state
*reg
, enum reg_arg_type t
)
1886 class = BPF_CLASS(code
);
1888 if (class == BPF_JMP
) {
1889 /* BPF_EXIT for "main" will reach here. Return TRUE
1894 if (op
== BPF_CALL
) {
1895 /* BPF to BPF call will reach here because of marking
1896 * caller saved clobber with DST_OP_NO_MARK for which we
1897 * don't care the register def because they are anyway
1898 * marked as NOT_INIT already.
1900 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
1902 /* Helper call will reach here because of arg type
1903 * check, conservatively return TRUE.
1912 if (class == BPF_ALU64
|| class == BPF_JMP
||
1913 /* BPF_END always use BPF_ALU class. */
1914 (class == BPF_ALU
&& op
== BPF_END
&& insn
->imm
== 64))
1917 if (class == BPF_ALU
|| class == BPF_JMP32
)
1920 if (class == BPF_LDX
) {
1922 return BPF_SIZE(code
) == BPF_DW
;
1923 /* LDX source must be ptr. */
1927 if (class == BPF_STX
) {
1928 /* BPF_STX (including atomic variants) has multiple source
1929 * operands, one of which is a ptr. Check whether the caller is
1932 if (t
== SRC_OP
&& reg
->type
!= SCALAR_VALUE
)
1934 return BPF_SIZE(code
) == BPF_DW
;
1937 if (class == BPF_LD
) {
1938 u8 mode
= BPF_MODE(code
);
1941 if (mode
== BPF_IMM
)
1944 /* Both LD_IND and LD_ABS return 32-bit data. */
1948 /* Implicit ctx ptr. */
1949 if (regno
== BPF_REG_6
)
1952 /* Explicit source could be any width. */
1956 if (class == BPF_ST
)
1957 /* The only source register for BPF_ST is a ptr. */
1960 /* Conservatively return true at default. */
1964 /* Return the regno defined by the insn, or -1. */
1965 static int insn_def_regno(const struct bpf_insn
*insn
)
1967 switch (BPF_CLASS(insn
->code
)) {
1973 if (BPF_MODE(insn
->code
) == BPF_ATOMIC
&&
1974 (insn
->imm
& BPF_FETCH
)) {
1975 if (insn
->imm
== BPF_CMPXCHG
)
1978 return insn
->src_reg
;
1983 return insn
->dst_reg
;
1987 /* Return TRUE if INSN has defined any 32-bit value explicitly. */
1988 static bool insn_has_def32(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
1990 int dst_reg
= insn_def_regno(insn
);
1995 return !is_reg64(env
, insn
, dst_reg
, NULL
, DST_OP
);
1998 static void mark_insn_zext(struct bpf_verifier_env
*env
,
1999 struct bpf_reg_state
*reg
)
2001 s32 def_idx
= reg
->subreg_def
;
2003 if (def_idx
== DEF_NOT_SUBREG
)
2006 env
->insn_aux_data
[def_idx
- 1].zext_dst
= true;
2007 /* The dst will be zero extended, so won't be sub-register anymore. */
2008 reg
->subreg_def
= DEF_NOT_SUBREG
;
2011 static int check_reg_arg(struct bpf_verifier_env
*env
, u32 regno
,
2012 enum reg_arg_type t
)
2014 struct bpf_verifier_state
*vstate
= env
->cur_state
;
2015 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
2016 struct bpf_insn
*insn
= env
->prog
->insnsi
+ env
->insn_idx
;
2017 struct bpf_reg_state
*reg
, *regs
= state
->regs
;
2020 if (regno
>= MAX_BPF_REG
) {
2021 verbose(env
, "R%d is invalid\n", regno
);
2026 rw64
= is_reg64(env
, insn
, regno
, reg
, t
);
2028 /* check whether register used as source operand can be read */
2029 if (reg
->type
== NOT_INIT
) {
2030 verbose(env
, "R%d !read_ok\n", regno
);
2033 /* We don't need to worry about FP liveness because it's read-only */
2034 if (regno
== BPF_REG_FP
)
2038 mark_insn_zext(env
, reg
);
2040 return mark_reg_read(env
, reg
, reg
->parent
,
2041 rw64
? REG_LIVE_READ64
: REG_LIVE_READ32
);
2043 /* check whether register used as dest operand can be written to */
2044 if (regno
== BPF_REG_FP
) {
2045 verbose(env
, "frame pointer is read only\n");
2048 reg
->live
|= REG_LIVE_WRITTEN
;
2049 reg
->subreg_def
= rw64
? DEF_NOT_SUBREG
: env
->insn_idx
+ 1;
2051 mark_reg_unknown(env
, regs
, regno
);
2056 /* for any branch, call, exit record the history of jmps in the given state */
2057 static int push_jmp_history(struct bpf_verifier_env
*env
,
2058 struct bpf_verifier_state
*cur
)
2060 u32 cnt
= cur
->jmp_history_cnt
;
2061 struct bpf_idx_pair
*p
;
2064 p
= krealloc(cur
->jmp_history
, cnt
* sizeof(*p
), GFP_USER
);
2067 p
[cnt
- 1].idx
= env
->insn_idx
;
2068 p
[cnt
- 1].prev_idx
= env
->prev_insn_idx
;
2069 cur
->jmp_history
= p
;
2070 cur
->jmp_history_cnt
= cnt
;
2074 /* Backtrack one insn at a time. If idx is not at the top of recorded
2075 * history then previous instruction came from straight line execution.
2077 static int get_prev_insn_idx(struct bpf_verifier_state
*st
, int i
,
2082 if (cnt
&& st
->jmp_history
[cnt
- 1].idx
== i
) {
2083 i
= st
->jmp_history
[cnt
- 1].prev_idx
;
2091 static const char *disasm_kfunc_name(void *data
, const struct bpf_insn
*insn
)
2093 const struct btf_type
*func
;
2095 if (insn
->src_reg
!= BPF_PSEUDO_KFUNC_CALL
)
2098 func
= btf_type_by_id(btf_vmlinux
, insn
->imm
);
2099 return btf_name_by_offset(btf_vmlinux
, func
->name_off
);
2102 /* For given verifier state backtrack_insn() is called from the last insn to
2103 * the first insn. Its purpose is to compute a bitmask of registers and
2104 * stack slots that needs precision in the parent verifier state.
2106 static int backtrack_insn(struct bpf_verifier_env
*env
, int idx
,
2107 u32
*reg_mask
, u64
*stack_mask
)
2109 const struct bpf_insn_cbs cbs
= {
2110 .cb_call
= disasm_kfunc_name
,
2111 .cb_print
= verbose
,
2112 .private_data
= env
,
2114 struct bpf_insn
*insn
= env
->prog
->insnsi
+ idx
;
2115 u8
class = BPF_CLASS(insn
->code
);
2116 u8 opcode
= BPF_OP(insn
->code
);
2117 u8 mode
= BPF_MODE(insn
->code
);
2118 u32 dreg
= 1u << insn
->dst_reg
;
2119 u32 sreg
= 1u << insn
->src_reg
;
2122 if (insn
->code
== 0)
2124 if (env
->log
.level
& BPF_LOG_LEVEL
) {
2125 verbose(env
, "regs=%x stack=%llx before ", *reg_mask
, *stack_mask
);
2126 verbose(env
, "%d: ", idx
);
2127 print_bpf_insn(&cbs
, insn
, env
->allow_ptr_leaks
);
2130 if (class == BPF_ALU
|| class == BPF_ALU64
) {
2131 if (!(*reg_mask
& dreg
))
2133 if (opcode
== BPF_MOV
) {
2134 if (BPF_SRC(insn
->code
) == BPF_X
) {
2136 * dreg needs precision after this insn
2137 * sreg needs precision before this insn
2143 * dreg needs precision after this insn.
2144 * Corresponding register is already marked
2145 * as precise=true in this verifier state.
2146 * No further markings in parent are necessary
2151 if (BPF_SRC(insn
->code
) == BPF_X
) {
2153 * both dreg and sreg need precision
2158 * dreg still needs precision before this insn
2161 } else if (class == BPF_LDX
) {
2162 if (!(*reg_mask
& dreg
))
2166 /* scalars can only be spilled into stack w/o losing precision.
2167 * Load from any other memory can be zero extended.
2168 * The desire to keep that precision is already indicated
2169 * by 'precise' mark in corresponding register of this state.
2170 * No further tracking necessary.
2172 if (insn
->src_reg
!= BPF_REG_FP
)
2174 if (BPF_SIZE(insn
->code
) != BPF_DW
)
2177 /* dreg = *(u64 *)[fp - off] was a fill from the stack.
2178 * that [fp - off] slot contains scalar that needs to be
2179 * tracked with precision
2181 spi
= (-insn
->off
- 1) / BPF_REG_SIZE
;
2183 verbose(env
, "BUG spi %d\n", spi
);
2184 WARN_ONCE(1, "verifier backtracking bug");
2187 *stack_mask
|= 1ull << spi
;
2188 } else if (class == BPF_STX
|| class == BPF_ST
) {
2189 if (*reg_mask
& dreg
)
2190 /* stx & st shouldn't be using _scalar_ dst_reg
2191 * to access memory. It means backtracking
2192 * encountered a case of pointer subtraction.
2195 /* scalars can only be spilled into stack */
2196 if (insn
->dst_reg
!= BPF_REG_FP
)
2198 if (BPF_SIZE(insn
->code
) != BPF_DW
)
2200 spi
= (-insn
->off
- 1) / BPF_REG_SIZE
;
2202 verbose(env
, "BUG spi %d\n", spi
);
2203 WARN_ONCE(1, "verifier backtracking bug");
2206 if (!(*stack_mask
& (1ull << spi
)))
2208 *stack_mask
&= ~(1ull << spi
);
2209 if (class == BPF_STX
)
2211 } else if (class == BPF_JMP
|| class == BPF_JMP32
) {
2212 if (opcode
== BPF_CALL
) {
2213 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
2215 /* regular helper call sets R0 */
2217 if (*reg_mask
& 0x3f) {
2218 /* if backtracing was looking for registers R1-R5
2219 * they should have been found already.
2221 verbose(env
, "BUG regs %x\n", *reg_mask
);
2222 WARN_ONCE(1, "verifier backtracking bug");
2225 } else if (opcode
== BPF_EXIT
) {
2228 } else if (class == BPF_LD
) {
2229 if (!(*reg_mask
& dreg
))
2232 /* It's ld_imm64 or ld_abs or ld_ind.
2233 * For ld_imm64 no further tracking of precision
2234 * into parent is necessary
2236 if (mode
== BPF_IND
|| mode
== BPF_ABS
)
2237 /* to be analyzed */
2243 /* the scalar precision tracking algorithm:
2244 * . at the start all registers have precise=false.
2245 * . scalar ranges are tracked as normal through alu and jmp insns.
2246 * . once precise value of the scalar register is used in:
2247 * . ptr + scalar alu
2248 * . if (scalar cond K|scalar)
2249 * . helper_call(.., scalar, ...) where ARG_CONST is expected
2250 * backtrack through the verifier states and mark all registers and
2251 * stack slots with spilled constants that these scalar regisers
2252 * should be precise.
2253 * . during state pruning two registers (or spilled stack slots)
2254 * are equivalent if both are not precise.
2256 * Note the verifier cannot simply walk register parentage chain,
2257 * since many different registers and stack slots could have been
2258 * used to compute single precise scalar.
2260 * The approach of starting with precise=true for all registers and then
2261 * backtrack to mark a register as not precise when the verifier detects
2262 * that program doesn't care about specific value (e.g., when helper
2263 * takes register as ARG_ANYTHING parameter) is not safe.
2265 * It's ok to walk single parentage chain of the verifier states.
2266 * It's possible that this backtracking will go all the way till 1st insn.
2267 * All other branches will be explored for needing precision later.
2269 * The backtracking needs to deal with cases like:
2270 * R8=map_value(id=0,off=0,ks=4,vs=1952,imm=0) R9_w=map_value(id=0,off=40,ks=4,vs=1952,imm=0)
2273 * if r5 > 0x79f goto pc+7
2274 * R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff))
2277 * call bpf_perf_event_output#25
2278 * where .arg5_type = ARG_CONST_SIZE_OR_ZERO
2282 * call foo // uses callee's r6 inside to compute r0
2286 * to track above reg_mask/stack_mask needs to be independent for each frame.
2288 * Also if parent's curframe > frame where backtracking started,
2289 * the verifier need to mark registers in both frames, otherwise callees
2290 * may incorrectly prune callers. This is similar to
2291 * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences")
2293 * For now backtracking falls back into conservative marking.
2295 static void mark_all_scalars_precise(struct bpf_verifier_env
*env
,
2296 struct bpf_verifier_state
*st
)
2298 struct bpf_func_state
*func
;
2299 struct bpf_reg_state
*reg
;
2302 /* big hammer: mark all scalars precise in this path.
2303 * pop_stack may still get !precise scalars.
2305 for (; st
; st
= st
->parent
)
2306 for (i
= 0; i
<= st
->curframe
; i
++) {
2307 func
= st
->frame
[i
];
2308 for (j
= 0; j
< BPF_REG_FP
; j
++) {
2309 reg
= &func
->regs
[j
];
2310 if (reg
->type
!= SCALAR_VALUE
)
2312 reg
->precise
= true;
2314 for (j
= 0; j
< func
->allocated_stack
/ BPF_REG_SIZE
; j
++) {
2315 if (func
->stack
[j
].slot_type
[0] != STACK_SPILL
)
2317 reg
= &func
->stack
[j
].spilled_ptr
;
2318 if (reg
->type
!= SCALAR_VALUE
)
2320 reg
->precise
= true;
2325 static int __mark_chain_precision(struct bpf_verifier_env
*env
, int regno
,
2328 struct bpf_verifier_state
*st
= env
->cur_state
;
2329 int first_idx
= st
->first_insn_idx
;
2330 int last_idx
= env
->insn_idx
;
2331 struct bpf_func_state
*func
;
2332 struct bpf_reg_state
*reg
;
2333 u32 reg_mask
= regno
>= 0 ? 1u << regno
: 0;
2334 u64 stack_mask
= spi
>= 0 ? 1ull << spi
: 0;
2335 bool skip_first
= true;
2336 bool new_marks
= false;
2339 if (!env
->bpf_capable
)
2342 func
= st
->frame
[st
->curframe
];
2344 reg
= &func
->regs
[regno
];
2345 if (reg
->type
!= SCALAR_VALUE
) {
2346 WARN_ONCE(1, "backtracing misuse");
2353 reg
->precise
= true;
2357 if (func
->stack
[spi
].slot_type
[0] != STACK_SPILL
) {
2361 reg
= &func
->stack
[spi
].spilled_ptr
;
2362 if (reg
->type
!= SCALAR_VALUE
) {
2370 reg
->precise
= true;
2376 if (!reg_mask
&& !stack_mask
)
2379 DECLARE_BITMAP(mask
, 64);
2380 u32 history
= st
->jmp_history_cnt
;
2382 if (env
->log
.level
& BPF_LOG_LEVEL
)
2383 verbose(env
, "last_idx %d first_idx %d\n", last_idx
, first_idx
);
2384 for (i
= last_idx
;;) {
2389 err
= backtrack_insn(env
, i
, ®_mask
, &stack_mask
);
2391 if (err
== -ENOTSUPP
) {
2392 mark_all_scalars_precise(env
, st
);
2397 if (!reg_mask
&& !stack_mask
)
2398 /* Found assignment(s) into tracked register in this state.
2399 * Since this state is already marked, just return.
2400 * Nothing to be tracked further in the parent state.
2405 i
= get_prev_insn_idx(st
, i
, &history
);
2406 if (i
>= env
->prog
->len
) {
2407 /* This can happen if backtracking reached insn 0
2408 * and there are still reg_mask or stack_mask
2410 * It means the backtracking missed the spot where
2411 * particular register was initialized with a constant.
2413 verbose(env
, "BUG backtracking idx %d\n", i
);
2414 WARN_ONCE(1, "verifier backtracking bug");
2423 func
= st
->frame
[st
->curframe
];
2424 bitmap_from_u64(mask
, reg_mask
);
2425 for_each_set_bit(i
, mask
, 32) {
2426 reg
= &func
->regs
[i
];
2427 if (reg
->type
!= SCALAR_VALUE
) {
2428 reg_mask
&= ~(1u << i
);
2433 reg
->precise
= true;
2436 bitmap_from_u64(mask
, stack_mask
);
2437 for_each_set_bit(i
, mask
, 64) {
2438 if (i
>= func
->allocated_stack
/ BPF_REG_SIZE
) {
2439 /* the sequence of instructions:
2441 * 3: (7b) *(u64 *)(r3 -8) = r0
2442 * 4: (79) r4 = *(u64 *)(r10 -8)
2443 * doesn't contain jmps. It's backtracked
2444 * as a single block.
2445 * During backtracking insn 3 is not recognized as
2446 * stack access, so at the end of backtracking
2447 * stack slot fp-8 is still marked in stack_mask.
2448 * However the parent state may not have accessed
2449 * fp-8 and it's "unallocated" stack space.
2450 * In such case fallback to conservative.
2452 mark_all_scalars_precise(env
, st
);
2456 if (func
->stack
[i
].slot_type
[0] != STACK_SPILL
) {
2457 stack_mask
&= ~(1ull << i
);
2460 reg
= &func
->stack
[i
].spilled_ptr
;
2461 if (reg
->type
!= SCALAR_VALUE
) {
2462 stack_mask
&= ~(1ull << i
);
2467 reg
->precise
= true;
2469 if (env
->log
.level
& BPF_LOG_LEVEL
) {
2470 print_verifier_state(env
, func
);
2471 verbose(env
, "parent %s regs=%x stack=%llx marks\n",
2472 new_marks
? "didn't have" : "already had",
2473 reg_mask
, stack_mask
);
2476 if (!reg_mask
&& !stack_mask
)
2481 last_idx
= st
->last_insn_idx
;
2482 first_idx
= st
->first_insn_idx
;
2487 static int mark_chain_precision(struct bpf_verifier_env
*env
, int regno
)
2489 return __mark_chain_precision(env
, regno
, -1);
2492 static int mark_chain_precision_stack(struct bpf_verifier_env
*env
, int spi
)
2494 return __mark_chain_precision(env
, -1, spi
);
2497 static bool is_spillable_regtype(enum bpf_reg_type type
)
2500 case PTR_TO_MAP_VALUE
:
2501 case PTR_TO_MAP_VALUE_OR_NULL
:
2505 case PTR_TO_PACKET_META
:
2506 case PTR_TO_PACKET_END
:
2507 case PTR_TO_FLOW_KEYS
:
2508 case CONST_PTR_TO_MAP
:
2510 case PTR_TO_SOCKET_OR_NULL
:
2511 case PTR_TO_SOCK_COMMON
:
2512 case PTR_TO_SOCK_COMMON_OR_NULL
:
2513 case PTR_TO_TCP_SOCK
:
2514 case PTR_TO_TCP_SOCK_OR_NULL
:
2515 case PTR_TO_XDP_SOCK
:
2517 case PTR_TO_BTF_ID_OR_NULL
:
2518 case PTR_TO_RDONLY_BUF
:
2519 case PTR_TO_RDONLY_BUF_OR_NULL
:
2520 case PTR_TO_RDWR_BUF
:
2521 case PTR_TO_RDWR_BUF_OR_NULL
:
2522 case PTR_TO_PERCPU_BTF_ID
:
2524 case PTR_TO_MEM_OR_NULL
:
2526 case PTR_TO_MAP_KEY
:
2533 /* Does this register contain a constant zero? */
2534 static bool register_is_null(struct bpf_reg_state
*reg
)
2536 return reg
->type
== SCALAR_VALUE
&& tnum_equals_const(reg
->var_off
, 0);
2539 static bool register_is_const(struct bpf_reg_state
*reg
)
2541 return reg
->type
== SCALAR_VALUE
&& tnum_is_const(reg
->var_off
);
2544 static bool __is_scalar_unbounded(struct bpf_reg_state
*reg
)
2546 return tnum_is_unknown(reg
->var_off
) &&
2547 reg
->smin_value
== S64_MIN
&& reg
->smax_value
== S64_MAX
&&
2548 reg
->umin_value
== 0 && reg
->umax_value
== U64_MAX
&&
2549 reg
->s32_min_value
== S32_MIN
&& reg
->s32_max_value
== S32_MAX
&&
2550 reg
->u32_min_value
== 0 && reg
->u32_max_value
== U32_MAX
;
2553 static bool register_is_bounded(struct bpf_reg_state
*reg
)
2555 return reg
->type
== SCALAR_VALUE
&& !__is_scalar_unbounded(reg
);
2558 static bool __is_pointer_value(bool allow_ptr_leaks
,
2559 const struct bpf_reg_state
*reg
)
2561 if (allow_ptr_leaks
)
2564 return reg
->type
!= SCALAR_VALUE
;
2567 static void save_register_state(struct bpf_func_state
*state
,
2568 int spi
, struct bpf_reg_state
*reg
)
2572 state
->stack
[spi
].spilled_ptr
= *reg
;
2573 state
->stack
[spi
].spilled_ptr
.live
|= REG_LIVE_WRITTEN
;
2575 for (i
= 0; i
< BPF_REG_SIZE
; i
++)
2576 state
->stack
[spi
].slot_type
[i
] = STACK_SPILL
;
2579 /* check_stack_{read,write}_fixed_off functions track spill/fill of registers,
2580 * stack boundary and alignment are checked in check_mem_access()
2582 static int check_stack_write_fixed_off(struct bpf_verifier_env
*env
,
2583 /* stack frame we're writing to */
2584 struct bpf_func_state
*state
,
2585 int off
, int size
, int value_regno
,
2588 struct bpf_func_state
*cur
; /* state of the current function */
2589 int i
, slot
= -off
- 1, spi
= slot
/ BPF_REG_SIZE
, err
;
2590 u32 dst_reg
= env
->prog
->insnsi
[insn_idx
].dst_reg
;
2591 struct bpf_reg_state
*reg
= NULL
;
2593 err
= realloc_func_state(state
, round_up(slot
+ 1, BPF_REG_SIZE
),
2594 state
->acquired_refs
, true);
2597 /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
2598 * so it's aligned access and [off, off + size) are within stack limits
2600 if (!env
->allow_ptr_leaks
&&
2601 state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
2602 size
!= BPF_REG_SIZE
) {
2603 verbose(env
, "attempt to corrupt spilled pointer on stack\n");
2607 cur
= env
->cur_state
->frame
[env
->cur_state
->curframe
];
2608 if (value_regno
>= 0)
2609 reg
= &cur
->regs
[value_regno
];
2611 if (reg
&& size
== BPF_REG_SIZE
&& register_is_bounded(reg
) &&
2612 !register_is_null(reg
) && env
->bpf_capable
) {
2613 if (dst_reg
!= BPF_REG_FP
) {
2614 /* The backtracking logic can only recognize explicit
2615 * stack slot address like [fp - 8]. Other spill of
2616 * scalar via different register has to be conervative.
2617 * Backtrack from here and mark all registers as precise
2618 * that contributed into 'reg' being a constant.
2620 err
= mark_chain_precision(env
, value_regno
);
2624 save_register_state(state
, spi
, reg
);
2625 } else if (reg
&& is_spillable_regtype(reg
->type
)) {
2626 /* register containing pointer is being spilled into stack */
2627 if (size
!= BPF_REG_SIZE
) {
2628 verbose_linfo(env
, insn_idx
, "; ");
2629 verbose(env
, "invalid size of register spill\n");
2633 if (state
!= cur
&& reg
->type
== PTR_TO_STACK
) {
2634 verbose(env
, "cannot spill pointers to stack into stack frame of the caller\n");
2638 if (!env
->bypass_spec_v4
) {
2639 bool sanitize
= false;
2641 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
2642 register_is_const(&state
->stack
[spi
].spilled_ptr
))
2644 for (i
= 0; i
< BPF_REG_SIZE
; i
++)
2645 if (state
->stack
[spi
].slot_type
[i
] == STACK_MISC
) {
2650 int *poff
= &env
->insn_aux_data
[insn_idx
].sanitize_stack_off
;
2651 int soff
= (-spi
- 1) * BPF_REG_SIZE
;
2653 /* detected reuse of integer stack slot with a pointer
2654 * which means either llvm is reusing stack slot or
2655 * an attacker is trying to exploit CVE-2018-3639
2656 * (speculative store bypass)
2657 * Have to sanitize that slot with preemptive
2660 if (*poff
&& *poff
!= soff
) {
2661 /* disallow programs where single insn stores
2662 * into two different stack slots, since verifier
2663 * cannot sanitize them
2666 "insn %d cannot access two stack slots fp%d and fp%d",
2667 insn_idx
, *poff
, soff
);
2673 save_register_state(state
, spi
, reg
);
2675 u8 type
= STACK_MISC
;
2677 /* regular write of data into stack destroys any spilled ptr */
2678 state
->stack
[spi
].spilled_ptr
.type
= NOT_INIT
;
2679 /* Mark slots as STACK_MISC if they belonged to spilled ptr. */
2680 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
)
2681 for (i
= 0; i
< BPF_REG_SIZE
; i
++)
2682 state
->stack
[spi
].slot_type
[i
] = STACK_MISC
;
2684 /* only mark the slot as written if all 8 bytes were written
2685 * otherwise read propagation may incorrectly stop too soon
2686 * when stack slots are partially written.
2687 * This heuristic means that read propagation will be
2688 * conservative, since it will add reg_live_read marks
2689 * to stack slots all the way to first state when programs
2690 * writes+reads less than 8 bytes
2692 if (size
== BPF_REG_SIZE
)
2693 state
->stack
[spi
].spilled_ptr
.live
|= REG_LIVE_WRITTEN
;
2695 /* when we zero initialize stack slots mark them as such */
2696 if (reg
&& register_is_null(reg
)) {
2697 /* backtracking doesn't work for STACK_ZERO yet. */
2698 err
= mark_chain_precision(env
, value_regno
);
2704 /* Mark slots affected by this stack write. */
2705 for (i
= 0; i
< size
; i
++)
2706 state
->stack
[spi
].slot_type
[(slot
- i
) % BPF_REG_SIZE
] =
2712 /* Write the stack: 'stack[ptr_regno + off] = value_regno'. 'ptr_regno' is
2713 * known to contain a variable offset.
2714 * This function checks whether the write is permitted and conservatively
2715 * tracks the effects of the write, considering that each stack slot in the
2716 * dynamic range is potentially written to.
2718 * 'off' includes 'regno->off'.
2719 * 'value_regno' can be -1, meaning that an unknown value is being written to
2722 * Spilled pointers in range are not marked as written because we don't know
2723 * what's going to be actually written. This means that read propagation for
2724 * future reads cannot be terminated by this write.
2726 * For privileged programs, uninitialized stack slots are considered
2727 * initialized by this write (even though we don't know exactly what offsets
2728 * are going to be written to). The idea is that we don't want the verifier to
2729 * reject future reads that access slots written to through variable offsets.
2731 static int check_stack_write_var_off(struct bpf_verifier_env
*env
,
2732 /* func where register points to */
2733 struct bpf_func_state
*state
,
2734 int ptr_regno
, int off
, int size
,
2735 int value_regno
, int insn_idx
)
2737 struct bpf_func_state
*cur
; /* state of the current function */
2738 int min_off
, max_off
;
2740 struct bpf_reg_state
*ptr_reg
= NULL
, *value_reg
= NULL
;
2741 bool writing_zero
= false;
2742 /* set if the fact that we're writing a zero is used to let any
2743 * stack slots remain STACK_ZERO
2745 bool zero_used
= false;
2747 cur
= env
->cur_state
->frame
[env
->cur_state
->curframe
];
2748 ptr_reg
= &cur
->regs
[ptr_regno
];
2749 min_off
= ptr_reg
->smin_value
+ off
;
2750 max_off
= ptr_reg
->smax_value
+ off
+ size
;
2751 if (value_regno
>= 0)
2752 value_reg
= &cur
->regs
[value_regno
];
2753 if (value_reg
&& register_is_null(value_reg
))
2754 writing_zero
= true;
2756 err
= realloc_func_state(state
, round_up(-min_off
, BPF_REG_SIZE
),
2757 state
->acquired_refs
, true);
2762 /* Variable offset writes destroy any spilled pointers in range. */
2763 for (i
= min_off
; i
< max_off
; i
++) {
2764 u8 new_type
, *stype
;
2768 spi
= slot
/ BPF_REG_SIZE
;
2769 stype
= &state
->stack
[spi
].slot_type
[slot
% BPF_REG_SIZE
];
2771 if (!env
->allow_ptr_leaks
2772 && *stype
!= NOT_INIT
2773 && *stype
!= SCALAR_VALUE
) {
2774 /* Reject the write if there's are spilled pointers in
2775 * range. If we didn't reject here, the ptr status
2776 * would be erased below (even though not all slots are
2777 * actually overwritten), possibly opening the door to
2780 verbose(env
, "spilled ptr in range of var-offset stack write; insn %d, ptr off: %d",
2785 /* Erase all spilled pointers. */
2786 state
->stack
[spi
].spilled_ptr
.type
= NOT_INIT
;
2788 /* Update the slot type. */
2789 new_type
= STACK_MISC
;
2790 if (writing_zero
&& *stype
== STACK_ZERO
) {
2791 new_type
= STACK_ZERO
;
2794 /* If the slot is STACK_INVALID, we check whether it's OK to
2795 * pretend that it will be initialized by this write. The slot
2796 * might not actually be written to, and so if we mark it as
2797 * initialized future reads might leak uninitialized memory.
2798 * For privileged programs, we will accept such reads to slots
2799 * that may or may not be written because, if we're reject
2800 * them, the error would be too confusing.
2802 if (*stype
== STACK_INVALID
&& !env
->allow_uninit_stack
) {
2803 verbose(env
, "uninit stack in range of var-offset write prohibited for !root; insn %d, off: %d",
2810 /* backtracking doesn't work for STACK_ZERO yet. */
2811 err
= mark_chain_precision(env
, value_regno
);
2818 /* When register 'dst_regno' is assigned some values from stack[min_off,
2819 * max_off), we set the register's type according to the types of the
2820 * respective stack slots. If all the stack values are known to be zeros, then
2821 * so is the destination reg. Otherwise, the register is considered to be
2822 * SCALAR. This function does not deal with register filling; the caller must
2823 * ensure that all spilled registers in the stack range have been marked as
2826 static void mark_reg_stack_read(struct bpf_verifier_env
*env
,
2827 /* func where src register points to */
2828 struct bpf_func_state
*ptr_state
,
2829 int min_off
, int max_off
, int dst_regno
)
2831 struct bpf_verifier_state
*vstate
= env
->cur_state
;
2832 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
2837 for (i
= min_off
; i
< max_off
; i
++) {
2839 spi
= slot
/ BPF_REG_SIZE
;
2840 stype
= ptr_state
->stack
[spi
].slot_type
;
2841 if (stype
[slot
% BPF_REG_SIZE
] != STACK_ZERO
)
2845 if (zeros
== max_off
- min_off
) {
2846 /* any access_size read into register is zero extended,
2847 * so the whole register == const_zero
2849 __mark_reg_const_zero(&state
->regs
[dst_regno
]);
2850 /* backtracking doesn't support STACK_ZERO yet,
2851 * so mark it precise here, so that later
2852 * backtracking can stop here.
2853 * Backtracking may not need this if this register
2854 * doesn't participate in pointer adjustment.
2855 * Forward propagation of precise flag is not
2856 * necessary either. This mark is only to stop
2857 * backtracking. Any register that contributed
2858 * to const 0 was marked precise before spill.
2860 state
->regs
[dst_regno
].precise
= true;
2862 /* have read misc data from the stack */
2863 mark_reg_unknown(env
, state
->regs
, dst_regno
);
2865 state
->regs
[dst_regno
].live
|= REG_LIVE_WRITTEN
;
2868 /* Read the stack at 'off' and put the results into the register indicated by
2869 * 'dst_regno'. It handles reg filling if the addressed stack slot is a
2872 * 'dst_regno' can be -1, meaning that the read value is not going to a
2875 * The access is assumed to be within the current stack bounds.
2877 static int check_stack_read_fixed_off(struct bpf_verifier_env
*env
,
2878 /* func where src register points to */
2879 struct bpf_func_state
*reg_state
,
2880 int off
, int size
, int dst_regno
)
2882 struct bpf_verifier_state
*vstate
= env
->cur_state
;
2883 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
2884 int i
, slot
= -off
- 1, spi
= slot
/ BPF_REG_SIZE
;
2885 struct bpf_reg_state
*reg
;
2888 stype
= reg_state
->stack
[spi
].slot_type
;
2889 reg
= ®_state
->stack
[spi
].spilled_ptr
;
2891 if (stype
[0] == STACK_SPILL
) {
2892 if (size
!= BPF_REG_SIZE
) {
2893 if (reg
->type
!= SCALAR_VALUE
) {
2894 verbose_linfo(env
, env
->insn_idx
, "; ");
2895 verbose(env
, "invalid size of register fill\n");
2898 if (dst_regno
>= 0) {
2899 mark_reg_unknown(env
, state
->regs
, dst_regno
);
2900 state
->regs
[dst_regno
].live
|= REG_LIVE_WRITTEN
;
2902 mark_reg_read(env
, reg
, reg
->parent
, REG_LIVE_READ64
);
2905 for (i
= 1; i
< BPF_REG_SIZE
; i
++) {
2906 if (stype
[(slot
- i
) % BPF_REG_SIZE
] != STACK_SPILL
) {
2907 verbose(env
, "corrupted spill memory\n");
2912 if (dst_regno
>= 0) {
2913 /* restore register state from stack */
2914 state
->regs
[dst_regno
] = *reg
;
2915 /* mark reg as written since spilled pointer state likely
2916 * has its liveness marks cleared by is_state_visited()
2917 * which resets stack/reg liveness for state transitions
2919 state
->regs
[dst_regno
].live
|= REG_LIVE_WRITTEN
;
2920 } else if (__is_pointer_value(env
->allow_ptr_leaks
, reg
)) {
2921 /* If dst_regno==-1, the caller is asking us whether
2922 * it is acceptable to use this value as a SCALAR_VALUE
2924 * We must not allow unprivileged callers to do that
2925 * with spilled pointers.
2927 verbose(env
, "leaking pointer from stack off %d\n",
2931 mark_reg_read(env
, reg
, reg
->parent
, REG_LIVE_READ64
);
2935 for (i
= 0; i
< size
; i
++) {
2936 type
= stype
[(slot
- i
) % BPF_REG_SIZE
];
2937 if (type
== STACK_MISC
)
2939 if (type
== STACK_ZERO
)
2941 verbose(env
, "invalid read from stack off %d+%d size %d\n",
2945 mark_reg_read(env
, reg
, reg
->parent
, REG_LIVE_READ64
);
2947 mark_reg_stack_read(env
, reg_state
, off
, off
+ size
, dst_regno
);
2952 enum stack_access_src
{
2953 ACCESS_DIRECT
= 1, /* the access is performed by an instruction */
2954 ACCESS_HELPER
= 2, /* the access is performed by a helper */
2957 static int check_stack_range_initialized(struct bpf_verifier_env
*env
,
2958 int regno
, int off
, int access_size
,
2959 bool zero_size_allowed
,
2960 enum stack_access_src type
,
2961 struct bpf_call_arg_meta
*meta
);
2963 static struct bpf_reg_state
*reg_state(struct bpf_verifier_env
*env
, int regno
)
2965 return cur_regs(env
) + regno
;
2968 /* Read the stack at 'ptr_regno + off' and put the result into the register
2970 * 'off' includes the pointer register's fixed offset(i.e. 'ptr_regno.off'),
2971 * but not its variable offset.
2972 * 'size' is assumed to be <= reg size and the access is assumed to be aligned.
2974 * As opposed to check_stack_read_fixed_off, this function doesn't deal with
2975 * filling registers (i.e. reads of spilled register cannot be detected when
2976 * the offset is not fixed). We conservatively mark 'dst_regno' as containing
2977 * SCALAR_VALUE. That's why we assert that the 'ptr_regno' has a variable
2978 * offset; for a fixed offset check_stack_read_fixed_off should be used
2981 static int check_stack_read_var_off(struct bpf_verifier_env
*env
,
2982 int ptr_regno
, int off
, int size
, int dst_regno
)
2984 /* The state of the source register. */
2985 struct bpf_reg_state
*reg
= reg_state(env
, ptr_regno
);
2986 struct bpf_func_state
*ptr_state
= func(env
, reg
);
2988 int min_off
, max_off
;
2990 /* Note that we pass a NULL meta, so raw access will not be permitted.
2992 err
= check_stack_range_initialized(env
, ptr_regno
, off
, size
,
2993 false, ACCESS_DIRECT
, NULL
);
2997 min_off
= reg
->smin_value
+ off
;
2998 max_off
= reg
->smax_value
+ off
;
2999 mark_reg_stack_read(env
, ptr_state
, min_off
, max_off
+ size
, dst_regno
);
3003 /* check_stack_read dispatches to check_stack_read_fixed_off or
3004 * check_stack_read_var_off.
3006 * The caller must ensure that the offset falls within the allocated stack
3009 * 'dst_regno' is a register which will receive the value from the stack. It
3010 * can be -1, meaning that the read value is not going to a register.
3012 static int check_stack_read(struct bpf_verifier_env
*env
,
3013 int ptr_regno
, int off
, int size
,
3016 struct bpf_reg_state
*reg
= reg_state(env
, ptr_regno
);
3017 struct bpf_func_state
*state
= func(env
, reg
);
3019 /* Some accesses are only permitted with a static offset. */
3020 bool var_off
= !tnum_is_const(reg
->var_off
);
3022 /* The offset is required to be static when reads don't go to a
3023 * register, in order to not leak pointers (see
3024 * check_stack_read_fixed_off).
3026 if (dst_regno
< 0 && var_off
) {
3029 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3030 verbose(env
, "variable offset stack pointer cannot be passed into helper function; var_off=%s off=%d size=%d\n",
3034 /* Variable offset is prohibited for unprivileged mode for simplicity
3035 * since it requires corresponding support in Spectre masking for stack
3036 * ALU. See also retrieve_ptr_limit().
3038 if (!env
->bypass_spec_v1
&& var_off
) {
3041 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3042 verbose(env
, "R%d variable offset stack access prohibited for !root, var_off=%s\n",
3048 off
+= reg
->var_off
.value
;
3049 err
= check_stack_read_fixed_off(env
, state
, off
, size
,
3052 /* Variable offset stack reads need more conservative handling
3053 * than fixed offset ones. Note that dst_regno >= 0 on this
3056 err
= check_stack_read_var_off(env
, ptr_regno
, off
, size
,
3063 /* check_stack_write dispatches to check_stack_write_fixed_off or
3064 * check_stack_write_var_off.
3066 * 'ptr_regno' is the register used as a pointer into the stack.
3067 * 'off' includes 'ptr_regno->off', but not its variable offset (if any).
3068 * 'value_regno' is the register whose value we're writing to the stack. It can
3069 * be -1, meaning that we're not writing from a register.
3071 * The caller must ensure that the offset falls within the maximum stack size.
3073 static int check_stack_write(struct bpf_verifier_env
*env
,
3074 int ptr_regno
, int off
, int size
,
3075 int value_regno
, int insn_idx
)
3077 struct bpf_reg_state
*reg
= reg_state(env
, ptr_regno
);
3078 struct bpf_func_state
*state
= func(env
, reg
);
3081 if (tnum_is_const(reg
->var_off
)) {
3082 off
+= reg
->var_off
.value
;
3083 err
= check_stack_write_fixed_off(env
, state
, off
, size
,
3084 value_regno
, insn_idx
);
3086 /* Variable offset stack reads need more conservative handling
3087 * than fixed offset ones.
3089 err
= check_stack_write_var_off(env
, state
,
3090 ptr_regno
, off
, size
,
3091 value_regno
, insn_idx
);
3096 static int check_map_access_type(struct bpf_verifier_env
*env
, u32 regno
,
3097 int off
, int size
, enum bpf_access_type type
)
3099 struct bpf_reg_state
*regs
= cur_regs(env
);
3100 struct bpf_map
*map
= regs
[regno
].map_ptr
;
3101 u32 cap
= bpf_map_flags_to_cap(map
);
3103 if (type
== BPF_WRITE
&& !(cap
& BPF_MAP_CAN_WRITE
)) {
3104 verbose(env
, "write into map forbidden, value_size=%d off=%d size=%d\n",
3105 map
->value_size
, off
, size
);
3109 if (type
== BPF_READ
&& !(cap
& BPF_MAP_CAN_READ
)) {
3110 verbose(env
, "read from map forbidden, value_size=%d off=%d size=%d\n",
3111 map
->value_size
, off
, size
);
3118 /* check read/write into memory region (e.g., map value, ringbuf sample, etc) */
3119 static int __check_mem_access(struct bpf_verifier_env
*env
, int regno
,
3120 int off
, int size
, u32 mem_size
,
3121 bool zero_size_allowed
)
3123 bool size_ok
= size
> 0 || (size
== 0 && zero_size_allowed
);
3124 struct bpf_reg_state
*reg
;
3126 if (off
>= 0 && size_ok
&& (u64
)off
+ size
<= mem_size
)
3129 reg
= &cur_regs(env
)[regno
];
3130 switch (reg
->type
) {
3131 case PTR_TO_MAP_KEY
:
3132 verbose(env
, "invalid access to map key, key_size=%d off=%d size=%d\n",
3133 mem_size
, off
, size
);
3135 case PTR_TO_MAP_VALUE
:
3136 verbose(env
, "invalid access to map value, value_size=%d off=%d size=%d\n",
3137 mem_size
, off
, size
);
3140 case PTR_TO_PACKET_META
:
3141 case PTR_TO_PACKET_END
:
3142 verbose(env
, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
3143 off
, size
, regno
, reg
->id
, off
, mem_size
);
3147 verbose(env
, "invalid access to memory, mem_size=%u off=%d size=%d\n",
3148 mem_size
, off
, size
);
3154 /* check read/write into a memory region with possible variable offset */
3155 static int check_mem_region_access(struct bpf_verifier_env
*env
, u32 regno
,
3156 int off
, int size
, u32 mem_size
,
3157 bool zero_size_allowed
)
3159 struct bpf_verifier_state
*vstate
= env
->cur_state
;
3160 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
3161 struct bpf_reg_state
*reg
= &state
->regs
[regno
];
3164 /* We may have adjusted the register pointing to memory region, so we
3165 * need to try adding each of min_value and max_value to off
3166 * to make sure our theoretical access will be safe.
3168 if (env
->log
.level
& BPF_LOG_LEVEL
)
3169 print_verifier_state(env
, state
);
3171 /* The minimum value is only important with signed
3172 * comparisons where we can't assume the floor of a
3173 * value is 0. If we are using signed variables for our
3174 * index'es we need to make sure that whatever we use
3175 * will have a set floor within our range.
3177 if (reg
->smin_value
< 0 &&
3178 (reg
->smin_value
== S64_MIN
||
3179 (off
+ reg
->smin_value
!= (s64
)(s32
)(off
+ reg
->smin_value
)) ||
3180 reg
->smin_value
+ off
< 0)) {
3181 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
3185 err
= __check_mem_access(env
, regno
, reg
->smin_value
+ off
, size
,
3186 mem_size
, zero_size_allowed
);
3188 verbose(env
, "R%d min value is outside of the allowed memory range\n",
3193 /* If we haven't set a max value then we need to bail since we can't be
3194 * sure we won't do bad things.
3195 * If reg->umax_value + off could overflow, treat that as unbounded too.
3197 if (reg
->umax_value
>= BPF_MAX_VAR_OFF
) {
3198 verbose(env
, "R%d unbounded memory access, make sure to bounds check any such access\n",
3202 err
= __check_mem_access(env
, regno
, reg
->umax_value
+ off
, size
,
3203 mem_size
, zero_size_allowed
);
3205 verbose(env
, "R%d max value is outside of the allowed memory range\n",
3213 /* check read/write into a map element with possible variable offset */
3214 static int check_map_access(struct bpf_verifier_env
*env
, u32 regno
,
3215 int off
, int size
, bool zero_size_allowed
)
3217 struct bpf_verifier_state
*vstate
= env
->cur_state
;
3218 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
3219 struct bpf_reg_state
*reg
= &state
->regs
[regno
];
3220 struct bpf_map
*map
= reg
->map_ptr
;
3223 err
= check_mem_region_access(env
, regno
, off
, size
, map
->value_size
,
3228 if (map_value_has_spin_lock(map
)) {
3229 u32 lock
= map
->spin_lock_off
;
3231 /* if any part of struct bpf_spin_lock can be touched by
3232 * load/store reject this program.
3233 * To check that [x1, x2) overlaps with [y1, y2)
3234 * it is sufficient to check x1 < y2 && y1 < x2.
3236 if (reg
->smin_value
+ off
< lock
+ sizeof(struct bpf_spin_lock
) &&
3237 lock
< reg
->umax_value
+ off
+ size
) {
3238 verbose(env
, "bpf_spin_lock cannot be accessed directly by load/store\n");
3245 #define MAX_PACKET_OFF 0xffff
3247 static enum bpf_prog_type
resolve_prog_type(struct bpf_prog
*prog
)
3249 return prog
->aux
->dst_prog
? prog
->aux
->dst_prog
->type
: prog
->type
;
3252 static bool may_access_direct_pkt_data(struct bpf_verifier_env
*env
,
3253 const struct bpf_call_arg_meta
*meta
,
3254 enum bpf_access_type t
)
3256 enum bpf_prog_type prog_type
= resolve_prog_type(env
->prog
);
3258 switch (prog_type
) {
3259 /* Program types only with direct read access go here! */
3260 case BPF_PROG_TYPE_LWT_IN
:
3261 case BPF_PROG_TYPE_LWT_OUT
:
3262 case BPF_PROG_TYPE_LWT_SEG6LOCAL
:
3263 case BPF_PROG_TYPE_SK_REUSEPORT
:
3264 case BPF_PROG_TYPE_FLOW_DISSECTOR
:
3265 case BPF_PROG_TYPE_CGROUP_SKB
:
3270 /* Program types with direct read + write access go here! */
3271 case BPF_PROG_TYPE_SCHED_CLS
:
3272 case BPF_PROG_TYPE_SCHED_ACT
:
3273 case BPF_PROG_TYPE_XDP
:
3274 case BPF_PROG_TYPE_LWT_XMIT
:
3275 case BPF_PROG_TYPE_SK_SKB
:
3276 case BPF_PROG_TYPE_SK_MSG
:
3278 return meta
->pkt_access
;
3280 env
->seen_direct_write
= true;
3283 case BPF_PROG_TYPE_CGROUP_SOCKOPT
:
3285 env
->seen_direct_write
= true;
3294 static int check_packet_access(struct bpf_verifier_env
*env
, u32 regno
, int off
,
3295 int size
, bool zero_size_allowed
)
3297 struct bpf_reg_state
*regs
= cur_regs(env
);
3298 struct bpf_reg_state
*reg
= ®s
[regno
];
3301 /* We may have added a variable offset to the packet pointer; but any
3302 * reg->range we have comes after that. We are only checking the fixed
3306 /* We don't allow negative numbers, because we aren't tracking enough
3307 * detail to prove they're safe.
3309 if (reg
->smin_value
< 0) {
3310 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
3315 err
= reg
->range
< 0 ? -EINVAL
:
3316 __check_mem_access(env
, regno
, off
, size
, reg
->range
,
3319 verbose(env
, "R%d offset is outside of the packet\n", regno
);
3323 /* __check_mem_access has made sure "off + size - 1" is within u16.
3324 * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
3325 * otherwise find_good_pkt_pointers would have refused to set range info
3326 * that __check_mem_access would have rejected this pkt access.
3327 * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
3329 env
->prog
->aux
->max_pkt_offset
=
3330 max_t(u32
, env
->prog
->aux
->max_pkt_offset
,
3331 off
+ reg
->umax_value
+ size
- 1);
3336 /* check access to 'struct bpf_context' fields. Supports fixed offsets only */
3337 static int check_ctx_access(struct bpf_verifier_env
*env
, int insn_idx
, int off
, int size
,
3338 enum bpf_access_type t
, enum bpf_reg_type
*reg_type
,
3339 struct btf
**btf
, u32
*btf_id
)
3341 struct bpf_insn_access_aux info
= {
3342 .reg_type
= *reg_type
,
3346 if (env
->ops
->is_valid_access
&&
3347 env
->ops
->is_valid_access(off
, size
, t
, env
->prog
, &info
)) {
3348 /* A non zero info.ctx_field_size indicates that this field is a
3349 * candidate for later verifier transformation to load the whole
3350 * field and then apply a mask when accessed with a narrower
3351 * access than actual ctx access size. A zero info.ctx_field_size
3352 * will only allow for whole field access and rejects any other
3353 * type of narrower access.
3355 *reg_type
= info
.reg_type
;
3357 if (*reg_type
== PTR_TO_BTF_ID
|| *reg_type
== PTR_TO_BTF_ID_OR_NULL
) {
3359 *btf_id
= info
.btf_id
;
3361 env
->insn_aux_data
[insn_idx
].ctx_field_size
= info
.ctx_field_size
;
3363 /* remember the offset of last byte accessed in ctx */
3364 if (env
->prog
->aux
->max_ctx_offset
< off
+ size
)
3365 env
->prog
->aux
->max_ctx_offset
= off
+ size
;
3369 verbose(env
, "invalid bpf_context access off=%d size=%d\n", off
, size
);
3373 static int check_flow_keys_access(struct bpf_verifier_env
*env
, int off
,
3376 if (size
< 0 || off
< 0 ||
3377 (u64
)off
+ size
> sizeof(struct bpf_flow_keys
)) {
3378 verbose(env
, "invalid access to flow keys off=%d size=%d\n",
3385 static int check_sock_access(struct bpf_verifier_env
*env
, int insn_idx
,
3386 u32 regno
, int off
, int size
,
3387 enum bpf_access_type t
)
3389 struct bpf_reg_state
*regs
= cur_regs(env
);
3390 struct bpf_reg_state
*reg
= ®s
[regno
];
3391 struct bpf_insn_access_aux info
= {};
3394 if (reg
->smin_value
< 0) {
3395 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
3400 switch (reg
->type
) {
3401 case PTR_TO_SOCK_COMMON
:
3402 valid
= bpf_sock_common_is_valid_access(off
, size
, t
, &info
);
3405 valid
= bpf_sock_is_valid_access(off
, size
, t
, &info
);
3407 case PTR_TO_TCP_SOCK
:
3408 valid
= bpf_tcp_sock_is_valid_access(off
, size
, t
, &info
);
3410 case PTR_TO_XDP_SOCK
:
3411 valid
= bpf_xdp_sock_is_valid_access(off
, size
, t
, &info
);
3419 env
->insn_aux_data
[insn_idx
].ctx_field_size
=
3420 info
.ctx_field_size
;
3424 verbose(env
, "R%d invalid %s access off=%d size=%d\n",
3425 regno
, reg_type_str
[reg
->type
], off
, size
);
3430 static bool is_pointer_value(struct bpf_verifier_env
*env
, int regno
)
3432 return __is_pointer_value(env
->allow_ptr_leaks
, reg_state(env
, regno
));
3435 static bool is_ctx_reg(struct bpf_verifier_env
*env
, int regno
)
3437 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
3439 return reg
->type
== PTR_TO_CTX
;
3442 static bool is_sk_reg(struct bpf_verifier_env
*env
, int regno
)
3444 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
3446 return type_is_sk_pointer(reg
->type
);
3449 static bool is_pkt_reg(struct bpf_verifier_env
*env
, int regno
)
3451 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
3453 return type_is_pkt_pointer(reg
->type
);
3456 static bool is_flow_key_reg(struct bpf_verifier_env
*env
, int regno
)
3458 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
3460 /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
3461 return reg
->type
== PTR_TO_FLOW_KEYS
;
3464 static int check_pkt_ptr_alignment(struct bpf_verifier_env
*env
,
3465 const struct bpf_reg_state
*reg
,
3466 int off
, int size
, bool strict
)
3468 struct tnum reg_off
;
3471 /* Byte size accesses are always allowed. */
3472 if (!strict
|| size
== 1)
3475 /* For platforms that do not have a Kconfig enabling
3476 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
3477 * NET_IP_ALIGN is universally set to '2'. And on platforms
3478 * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
3479 * to this code only in strict mode where we want to emulate
3480 * the NET_IP_ALIGN==2 checking. Therefore use an
3481 * unconditional IP align value of '2'.
3485 reg_off
= tnum_add(reg
->var_off
, tnum_const(ip_align
+ reg
->off
+ off
));
3486 if (!tnum_is_aligned(reg_off
, size
)) {
3489 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3491 "misaligned packet access off %d+%s+%d+%d size %d\n",
3492 ip_align
, tn_buf
, reg
->off
, off
, size
);
3499 static int check_generic_ptr_alignment(struct bpf_verifier_env
*env
,
3500 const struct bpf_reg_state
*reg
,
3501 const char *pointer_desc
,
3502 int off
, int size
, bool strict
)
3504 struct tnum reg_off
;
3506 /* Byte size accesses are always allowed. */
3507 if (!strict
|| size
== 1)
3510 reg_off
= tnum_add(reg
->var_off
, tnum_const(reg
->off
+ off
));
3511 if (!tnum_is_aligned(reg_off
, size
)) {
3514 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3515 verbose(env
, "misaligned %saccess off %s+%d+%d size %d\n",
3516 pointer_desc
, tn_buf
, reg
->off
, off
, size
);
3523 static int check_ptr_alignment(struct bpf_verifier_env
*env
,
3524 const struct bpf_reg_state
*reg
, int off
,
3525 int size
, bool strict_alignment_once
)
3527 bool strict
= env
->strict_alignment
|| strict_alignment_once
;
3528 const char *pointer_desc
= "";
3530 switch (reg
->type
) {
3532 case PTR_TO_PACKET_META
:
3533 /* Special case, because of NET_IP_ALIGN. Given metadata sits
3534 * right in front, treat it the very same way.
3536 return check_pkt_ptr_alignment(env
, reg
, off
, size
, strict
);
3537 case PTR_TO_FLOW_KEYS
:
3538 pointer_desc
= "flow keys ";
3540 case PTR_TO_MAP_KEY
:
3541 pointer_desc
= "key ";
3543 case PTR_TO_MAP_VALUE
:
3544 pointer_desc
= "value ";
3547 pointer_desc
= "context ";
3550 pointer_desc
= "stack ";
3551 /* The stack spill tracking logic in check_stack_write_fixed_off()
3552 * and check_stack_read_fixed_off() relies on stack accesses being
3558 pointer_desc
= "sock ";
3560 case PTR_TO_SOCK_COMMON
:
3561 pointer_desc
= "sock_common ";
3563 case PTR_TO_TCP_SOCK
:
3564 pointer_desc
= "tcp_sock ";
3566 case PTR_TO_XDP_SOCK
:
3567 pointer_desc
= "xdp_sock ";
3572 return check_generic_ptr_alignment(env
, reg
, pointer_desc
, off
, size
,
3576 static int update_stack_depth(struct bpf_verifier_env
*env
,
3577 const struct bpf_func_state
*func
,
3580 u16 stack
= env
->subprog_info
[func
->subprogno
].stack_depth
;
3585 /* update known max for given subprogram */
3586 env
->subprog_info
[func
->subprogno
].stack_depth
= -off
;
3590 /* starting from main bpf function walk all instructions of the function
3591 * and recursively walk all callees that given function can call.
3592 * Ignore jump and exit insns.
3593 * Since recursion is prevented by check_cfg() this algorithm
3594 * only needs a local stack of MAX_CALL_FRAMES to remember callsites
3596 static int check_max_stack_depth(struct bpf_verifier_env
*env
)
3598 int depth
= 0, frame
= 0, idx
= 0, i
= 0, subprog_end
;
3599 struct bpf_subprog_info
*subprog
= env
->subprog_info
;
3600 struct bpf_insn
*insn
= env
->prog
->insnsi
;
3601 bool tail_call_reachable
= false;
3602 int ret_insn
[MAX_CALL_FRAMES
];
3603 int ret_prog
[MAX_CALL_FRAMES
];
3607 /* protect against potential stack overflow that might happen when
3608 * bpf2bpf calls get combined with tailcalls. Limit the caller's stack
3609 * depth for such case down to 256 so that the worst case scenario
3610 * would result in 8k stack size (32 which is tailcall limit * 256 =
3613 * To get the idea what might happen, see an example:
3614 * func1 -> sub rsp, 128
3615 * subfunc1 -> sub rsp, 256
3616 * tailcall1 -> add rsp, 256
3617 * func2 -> sub rsp, 192 (total stack size = 128 + 192 = 320)
3618 * subfunc2 -> sub rsp, 64
3619 * subfunc22 -> sub rsp, 128
3620 * tailcall2 -> add rsp, 128
3621 * func3 -> sub rsp, 32 (total stack size 128 + 192 + 64 + 32 = 416)
3623 * tailcall will unwind the current stack frame but it will not get rid
3624 * of caller's stack as shown on the example above.
3626 if (idx
&& subprog
[idx
].has_tail_call
&& depth
>= 256) {
3628 "tail_calls are not allowed when call stack of previous frames is %d bytes. Too large\n",
3632 /* round up to 32-bytes, since this is granularity
3633 * of interpreter stack size
3635 depth
+= round_up(max_t(u32
, subprog
[idx
].stack_depth
, 1), 32);
3636 if (depth
> MAX_BPF_STACK
) {
3637 verbose(env
, "combined stack size of %d calls is %d. Too large\n",
3642 subprog_end
= subprog
[idx
+ 1].start
;
3643 for (; i
< subprog_end
; i
++) {
3644 if (!bpf_pseudo_call(insn
+ i
) && !bpf_pseudo_func(insn
+ i
))
3646 /* remember insn and function to return to */
3647 ret_insn
[frame
] = i
+ 1;
3648 ret_prog
[frame
] = idx
;
3650 /* find the callee */
3651 i
= i
+ insn
[i
].imm
+ 1;
3652 idx
= find_subprog(env
, i
);
3654 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
3659 if (subprog
[idx
].has_tail_call
)
3660 tail_call_reachable
= true;
3663 if (frame
>= MAX_CALL_FRAMES
) {
3664 verbose(env
, "the call stack of %d frames is too deep !\n",
3670 /* if tail call got detected across bpf2bpf calls then mark each of the
3671 * currently present subprog frames as tail call reachable subprogs;
3672 * this info will be utilized by JIT so that we will be preserving the
3673 * tail call counter throughout bpf2bpf calls combined with tailcalls
3675 if (tail_call_reachable
)
3676 for (j
= 0; j
< frame
; j
++)
3677 subprog
[ret_prog
[j
]].tail_call_reachable
= true;
3679 /* end of for() loop means the last insn of the 'subprog'
3680 * was reached. Doesn't matter whether it was JA or EXIT
3684 depth
-= round_up(max_t(u32
, subprog
[idx
].stack_depth
, 1), 32);
3686 i
= ret_insn
[frame
];
3687 idx
= ret_prog
[frame
];
3691 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
3692 static int get_callee_stack_depth(struct bpf_verifier_env
*env
,
3693 const struct bpf_insn
*insn
, int idx
)
3695 int start
= idx
+ insn
->imm
+ 1, subprog
;
3697 subprog
= find_subprog(env
, start
);
3699 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
3703 return env
->subprog_info
[subprog
].stack_depth
;
3707 int check_ctx_reg(struct bpf_verifier_env
*env
,
3708 const struct bpf_reg_state
*reg
, int regno
)
3710 /* Access to ctx or passing it to a helper is only allowed in
3711 * its original, unmodified form.
3715 verbose(env
, "dereference of modified ctx ptr R%d off=%d disallowed\n",
3720 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
3723 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3724 verbose(env
, "variable ctx access var_off=%s disallowed\n", tn_buf
);
3731 static int __check_buffer_access(struct bpf_verifier_env
*env
,
3732 const char *buf_info
,
3733 const struct bpf_reg_state
*reg
,
3734 int regno
, int off
, int size
)
3738 "R%d invalid %s buffer access: off=%d, size=%d\n",
3739 regno
, buf_info
, off
, size
);
3742 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
3745 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3747 "R%d invalid variable buffer offset: off=%d, var_off=%s\n",
3748 regno
, off
, tn_buf
);
3755 static int check_tp_buffer_access(struct bpf_verifier_env
*env
,
3756 const struct bpf_reg_state
*reg
,
3757 int regno
, int off
, int size
)
3761 err
= __check_buffer_access(env
, "tracepoint", reg
, regno
, off
, size
);
3765 if (off
+ size
> env
->prog
->aux
->max_tp_access
)
3766 env
->prog
->aux
->max_tp_access
= off
+ size
;
3771 static int check_buffer_access(struct bpf_verifier_env
*env
,
3772 const struct bpf_reg_state
*reg
,
3773 int regno
, int off
, int size
,
3774 bool zero_size_allowed
,
3775 const char *buf_info
,
3780 err
= __check_buffer_access(env
, buf_info
, reg
, regno
, off
, size
);
3784 if (off
+ size
> *max_access
)
3785 *max_access
= off
+ size
;
3790 /* BPF architecture zero extends alu32 ops into 64-bit registesr */
3791 static void zext_32_to_64(struct bpf_reg_state
*reg
)
3793 reg
->var_off
= tnum_subreg(reg
->var_off
);
3794 __reg_assign_32_into_64(reg
);
3797 /* truncate register to smaller size (in bytes)
3798 * must be called with size < BPF_REG_SIZE
3800 static void coerce_reg_to_size(struct bpf_reg_state
*reg
, int size
)
3804 /* clear high bits in bit representation */
3805 reg
->var_off
= tnum_cast(reg
->var_off
, size
);
3807 /* fix arithmetic bounds */
3808 mask
= ((u64
)1 << (size
* 8)) - 1;
3809 if ((reg
->umin_value
& ~mask
) == (reg
->umax_value
& ~mask
)) {
3810 reg
->umin_value
&= mask
;
3811 reg
->umax_value
&= mask
;
3813 reg
->umin_value
= 0;
3814 reg
->umax_value
= mask
;
3816 reg
->smin_value
= reg
->umin_value
;
3817 reg
->smax_value
= reg
->umax_value
;
3819 /* If size is smaller than 32bit register the 32bit register
3820 * values are also truncated so we push 64-bit bounds into
3821 * 32-bit bounds. Above were truncated < 32-bits already.
3825 __reg_combine_64_into_32(reg
);
3828 static bool bpf_map_is_rdonly(const struct bpf_map
*map
)
3830 return (map
->map_flags
& BPF_F_RDONLY_PROG
) && map
->frozen
;
3833 static int bpf_map_direct_read(struct bpf_map
*map
, int off
, int size
, u64
*val
)
3839 err
= map
->ops
->map_direct_value_addr(map
, &addr
, off
);
3842 ptr
= (void *)(long)addr
+ off
;
3846 *val
= (u64
)*(u8
*)ptr
;
3849 *val
= (u64
)*(u16
*)ptr
;
3852 *val
= (u64
)*(u32
*)ptr
;
3863 static int check_ptr_to_btf_access(struct bpf_verifier_env
*env
,
3864 struct bpf_reg_state
*regs
,
3865 int regno
, int off
, int size
,
3866 enum bpf_access_type atype
,
3869 struct bpf_reg_state
*reg
= regs
+ regno
;
3870 const struct btf_type
*t
= btf_type_by_id(reg
->btf
, reg
->btf_id
);
3871 const char *tname
= btf_name_by_offset(reg
->btf
, t
->name_off
);
3877 "R%d is ptr_%s invalid negative access: off=%d\n",
3881 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
3884 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3886 "R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n",
3887 regno
, tname
, off
, tn_buf
);
3891 if (env
->ops
->btf_struct_access
) {
3892 ret
= env
->ops
->btf_struct_access(&env
->log
, reg
->btf
, t
,
3893 off
, size
, atype
, &btf_id
);
3895 if (atype
!= BPF_READ
) {
3896 verbose(env
, "only read is supported\n");
3900 ret
= btf_struct_access(&env
->log
, reg
->btf
, t
, off
, size
,
3907 if (atype
== BPF_READ
&& value_regno
>= 0)
3908 mark_btf_ld_reg(env
, regs
, value_regno
, ret
, reg
->btf
, btf_id
);
3913 static int check_ptr_to_map_access(struct bpf_verifier_env
*env
,
3914 struct bpf_reg_state
*regs
,
3915 int regno
, int off
, int size
,
3916 enum bpf_access_type atype
,
3919 struct bpf_reg_state
*reg
= regs
+ regno
;
3920 struct bpf_map
*map
= reg
->map_ptr
;
3921 const struct btf_type
*t
;
3927 verbose(env
, "map_ptr access not supported without CONFIG_DEBUG_INFO_BTF\n");
3931 if (!map
->ops
->map_btf_id
|| !*map
->ops
->map_btf_id
) {
3932 verbose(env
, "map_ptr access not supported for map type %d\n",
3937 t
= btf_type_by_id(btf_vmlinux
, *map
->ops
->map_btf_id
);
3938 tname
= btf_name_by_offset(btf_vmlinux
, t
->name_off
);
3940 if (!env
->allow_ptr_to_map_access
) {
3942 "%s access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
3948 verbose(env
, "R%d is %s invalid negative access: off=%d\n",
3953 if (atype
!= BPF_READ
) {
3954 verbose(env
, "only read from %s is supported\n", tname
);
3958 ret
= btf_struct_access(&env
->log
, btf_vmlinux
, t
, off
, size
, atype
, &btf_id
);
3962 if (value_regno
>= 0)
3963 mark_btf_ld_reg(env
, regs
, value_regno
, ret
, btf_vmlinux
, btf_id
);
3968 /* Check that the stack access at the given offset is within bounds. The
3969 * maximum valid offset is -1.
3971 * The minimum valid offset is -MAX_BPF_STACK for writes, and
3972 * -state->allocated_stack for reads.
3974 static int check_stack_slot_within_bounds(int off
,
3975 struct bpf_func_state
*state
,
3976 enum bpf_access_type t
)
3981 min_valid_off
= -MAX_BPF_STACK
;
3983 min_valid_off
= -state
->allocated_stack
;
3985 if (off
< min_valid_off
|| off
> -1)
3990 /* Check that the stack access at 'regno + off' falls within the maximum stack
3993 * 'off' includes `regno->offset`, but not its dynamic part (if any).
3995 static int check_stack_access_within_bounds(
3996 struct bpf_verifier_env
*env
,
3997 int regno
, int off
, int access_size
,
3998 enum stack_access_src src
, enum bpf_access_type type
)
4000 struct bpf_reg_state
*regs
= cur_regs(env
);
4001 struct bpf_reg_state
*reg
= regs
+ regno
;
4002 struct bpf_func_state
*state
= func(env
, reg
);
4003 int min_off
, max_off
;
4007 if (src
== ACCESS_HELPER
)
4008 /* We don't know if helpers are reading or writing (or both). */
4009 err_extra
= " indirect access to";
4010 else if (type
== BPF_READ
)
4011 err_extra
= " read from";
4013 err_extra
= " write to";
4015 if (tnum_is_const(reg
->var_off
)) {
4016 min_off
= reg
->var_off
.value
+ off
;
4017 if (access_size
> 0)
4018 max_off
= min_off
+ access_size
- 1;
4022 if (reg
->smax_value
>= BPF_MAX_VAR_OFF
||
4023 reg
->smin_value
<= -BPF_MAX_VAR_OFF
) {
4024 verbose(env
, "invalid unbounded variable-offset%s stack R%d\n",
4028 min_off
= reg
->smin_value
+ off
;
4029 if (access_size
> 0)
4030 max_off
= reg
->smax_value
+ off
+ access_size
- 1;
4035 err
= check_stack_slot_within_bounds(min_off
, state
, type
);
4037 err
= check_stack_slot_within_bounds(max_off
, state
, type
);
4040 if (tnum_is_const(reg
->var_off
)) {
4041 verbose(env
, "invalid%s stack R%d off=%d size=%d\n",
4042 err_extra
, regno
, off
, access_size
);
4046 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
4047 verbose(env
, "invalid variable-offset%s stack R%d var_off=%s size=%d\n",
4048 err_extra
, regno
, tn_buf
, access_size
);
4054 /* check whether memory at (regno + off) is accessible for t = (read | write)
4055 * if t==write, value_regno is a register which value is stored into memory
4056 * if t==read, value_regno is a register which will receive the value from memory
4057 * if t==write && value_regno==-1, some unknown value is stored into memory
4058 * if t==read && value_regno==-1, don't care what we read from memory
4060 static int check_mem_access(struct bpf_verifier_env
*env
, int insn_idx
, u32 regno
,
4061 int off
, int bpf_size
, enum bpf_access_type t
,
4062 int value_regno
, bool strict_alignment_once
)
4064 struct bpf_reg_state
*regs
= cur_regs(env
);
4065 struct bpf_reg_state
*reg
= regs
+ regno
;
4066 struct bpf_func_state
*state
;
4069 size
= bpf_size_to_bytes(bpf_size
);
4073 /* alignment checks will add in reg->off themselves */
4074 err
= check_ptr_alignment(env
, reg
, off
, size
, strict_alignment_once
);
4078 /* for access checks, reg->off is just part of off */
4081 if (reg
->type
== PTR_TO_MAP_KEY
) {
4082 if (t
== BPF_WRITE
) {
4083 verbose(env
, "write to change key R%d not allowed\n", regno
);
4087 err
= check_mem_region_access(env
, regno
, off
, size
,
4088 reg
->map_ptr
->key_size
, false);
4091 if (value_regno
>= 0)
4092 mark_reg_unknown(env
, regs
, value_regno
);
4093 } else if (reg
->type
== PTR_TO_MAP_VALUE
) {
4094 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
4095 is_pointer_value(env
, value_regno
)) {
4096 verbose(env
, "R%d leaks addr into map\n", value_regno
);
4099 err
= check_map_access_type(env
, regno
, off
, size
, t
);
4102 err
= check_map_access(env
, regno
, off
, size
, false);
4103 if (!err
&& t
== BPF_READ
&& value_regno
>= 0) {
4104 struct bpf_map
*map
= reg
->map_ptr
;
4106 /* if map is read-only, track its contents as scalars */
4107 if (tnum_is_const(reg
->var_off
) &&
4108 bpf_map_is_rdonly(map
) &&
4109 map
->ops
->map_direct_value_addr
) {
4110 int map_off
= off
+ reg
->var_off
.value
;
4113 err
= bpf_map_direct_read(map
, map_off
, size
,
4118 regs
[value_regno
].type
= SCALAR_VALUE
;
4119 __mark_reg_known(®s
[value_regno
], val
);
4121 mark_reg_unknown(env
, regs
, value_regno
);
4124 } else if (reg
->type
== PTR_TO_MEM
) {
4125 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
4126 is_pointer_value(env
, value_regno
)) {
4127 verbose(env
, "R%d leaks addr into mem\n", value_regno
);
4130 err
= check_mem_region_access(env
, regno
, off
, size
,
4131 reg
->mem_size
, false);
4132 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
4133 mark_reg_unknown(env
, regs
, value_regno
);
4134 } else if (reg
->type
== PTR_TO_CTX
) {
4135 enum bpf_reg_type reg_type
= SCALAR_VALUE
;
4136 struct btf
*btf
= NULL
;
4139 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
4140 is_pointer_value(env
, value_regno
)) {
4141 verbose(env
, "R%d leaks addr into ctx\n", value_regno
);
4145 err
= check_ctx_reg(env
, reg
, regno
);
4149 err
= check_ctx_access(env
, insn_idx
, off
, size
, t
, ®_type
, &btf
, &btf_id
);
4151 verbose_linfo(env
, insn_idx
, "; ");
4152 if (!err
&& t
== BPF_READ
&& value_regno
>= 0) {
4153 /* ctx access returns either a scalar, or a
4154 * PTR_TO_PACKET[_META,_END]. In the latter
4155 * case, we know the offset is zero.
4157 if (reg_type
== SCALAR_VALUE
) {
4158 mark_reg_unknown(env
, regs
, value_regno
);
4160 mark_reg_known_zero(env
, regs
,
4162 if (reg_type_may_be_null(reg_type
))
4163 regs
[value_regno
].id
= ++env
->id_gen
;
4164 /* A load of ctx field could have different
4165 * actual load size with the one encoded in the
4166 * insn. When the dst is PTR, it is for sure not
4169 regs
[value_regno
].subreg_def
= DEF_NOT_SUBREG
;
4170 if (reg_type
== PTR_TO_BTF_ID
||
4171 reg_type
== PTR_TO_BTF_ID_OR_NULL
) {
4172 regs
[value_regno
].btf
= btf
;
4173 regs
[value_regno
].btf_id
= btf_id
;
4176 regs
[value_regno
].type
= reg_type
;
4179 } else if (reg
->type
== PTR_TO_STACK
) {
4180 /* Basic bounds checks. */
4181 err
= check_stack_access_within_bounds(env
, regno
, off
, size
, ACCESS_DIRECT
, t
);
4185 state
= func(env
, reg
);
4186 err
= update_stack_depth(env
, state
, off
);
4191 err
= check_stack_read(env
, regno
, off
, size
,
4194 err
= check_stack_write(env
, regno
, off
, size
,
4195 value_regno
, insn_idx
);
4196 } else if (reg_is_pkt_pointer(reg
)) {
4197 if (t
== BPF_WRITE
&& !may_access_direct_pkt_data(env
, NULL
, t
)) {
4198 verbose(env
, "cannot write into packet\n");
4201 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
4202 is_pointer_value(env
, value_regno
)) {
4203 verbose(env
, "R%d leaks addr into packet\n",
4207 err
= check_packet_access(env
, regno
, off
, size
, false);
4208 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
4209 mark_reg_unknown(env
, regs
, value_regno
);
4210 } else if (reg
->type
== PTR_TO_FLOW_KEYS
) {
4211 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
4212 is_pointer_value(env
, value_regno
)) {
4213 verbose(env
, "R%d leaks addr into flow keys\n",
4218 err
= check_flow_keys_access(env
, off
, size
);
4219 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
4220 mark_reg_unknown(env
, regs
, value_regno
);
4221 } else if (type_is_sk_pointer(reg
->type
)) {
4222 if (t
== BPF_WRITE
) {
4223 verbose(env
, "R%d cannot write into %s\n",
4224 regno
, reg_type_str
[reg
->type
]);
4227 err
= check_sock_access(env
, insn_idx
, regno
, off
, size
, t
);
4228 if (!err
&& value_regno
>= 0)
4229 mark_reg_unknown(env
, regs
, value_regno
);
4230 } else if (reg
->type
== PTR_TO_TP_BUFFER
) {
4231 err
= check_tp_buffer_access(env
, reg
, regno
, off
, size
);
4232 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
4233 mark_reg_unknown(env
, regs
, value_regno
);
4234 } else if (reg
->type
== PTR_TO_BTF_ID
) {
4235 err
= check_ptr_to_btf_access(env
, regs
, regno
, off
, size
, t
,
4237 } else if (reg
->type
== CONST_PTR_TO_MAP
) {
4238 err
= check_ptr_to_map_access(env
, regs
, regno
, off
, size
, t
,
4240 } else if (reg
->type
== PTR_TO_RDONLY_BUF
) {
4241 if (t
== BPF_WRITE
) {
4242 verbose(env
, "R%d cannot write into %s\n",
4243 regno
, reg_type_str
[reg
->type
]);
4246 err
= check_buffer_access(env
, reg
, regno
, off
, size
, false,
4248 &env
->prog
->aux
->max_rdonly_access
);
4249 if (!err
&& value_regno
>= 0)
4250 mark_reg_unknown(env
, regs
, value_regno
);
4251 } else if (reg
->type
== PTR_TO_RDWR_BUF
) {
4252 err
= check_buffer_access(env
, reg
, regno
, off
, size
, false,
4254 &env
->prog
->aux
->max_rdwr_access
);
4255 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
4256 mark_reg_unknown(env
, regs
, value_regno
);
4258 verbose(env
, "R%d invalid mem access '%s'\n", regno
,
4259 reg_type_str
[reg
->type
]);
4263 if (!err
&& size
< BPF_REG_SIZE
&& value_regno
>= 0 && t
== BPF_READ
&&
4264 regs
[value_regno
].type
== SCALAR_VALUE
) {
4265 /* b/h/w load zero-extends, mark upper bits as known 0 */
4266 coerce_reg_to_size(®s
[value_regno
], size
);
4271 static int check_atomic(struct bpf_verifier_env
*env
, int insn_idx
, struct bpf_insn
*insn
)
4276 switch (insn
->imm
) {
4278 case BPF_ADD
| BPF_FETCH
:
4280 case BPF_AND
| BPF_FETCH
:
4282 case BPF_OR
| BPF_FETCH
:
4284 case BPF_XOR
| BPF_FETCH
:
4289 verbose(env
, "BPF_ATOMIC uses invalid atomic opcode %02x\n", insn
->imm
);
4293 if (BPF_SIZE(insn
->code
) != BPF_W
&& BPF_SIZE(insn
->code
) != BPF_DW
) {
4294 verbose(env
, "invalid atomic operand size\n");
4298 /* check src1 operand */
4299 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
4303 /* check src2 operand */
4304 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
4308 if (insn
->imm
== BPF_CMPXCHG
) {
4309 /* Check comparison of R0 with memory location */
4310 err
= check_reg_arg(env
, BPF_REG_0
, SRC_OP
);
4315 if (is_pointer_value(env
, insn
->src_reg
)) {
4316 verbose(env
, "R%d leaks addr into mem\n", insn
->src_reg
);
4320 if (is_ctx_reg(env
, insn
->dst_reg
) ||
4321 is_pkt_reg(env
, insn
->dst_reg
) ||
4322 is_flow_key_reg(env
, insn
->dst_reg
) ||
4323 is_sk_reg(env
, insn
->dst_reg
)) {
4324 verbose(env
, "BPF_ATOMIC stores into R%d %s is not allowed\n",
4326 reg_type_str
[reg_state(env
, insn
->dst_reg
)->type
]);
4330 if (insn
->imm
& BPF_FETCH
) {
4331 if (insn
->imm
== BPF_CMPXCHG
)
4332 load_reg
= BPF_REG_0
;
4334 load_reg
= insn
->src_reg
;
4336 /* check and record load of old value */
4337 err
= check_reg_arg(env
, load_reg
, DST_OP
);
4341 /* This instruction accesses a memory location but doesn't
4342 * actually load it into a register.
4347 /* check whether we can read the memory */
4348 err
= check_mem_access(env
, insn_idx
, insn
->dst_reg
, insn
->off
,
4349 BPF_SIZE(insn
->code
), BPF_READ
, load_reg
, true);
4353 /* check whether we can write into the same memory */
4354 err
= check_mem_access(env
, insn_idx
, insn
->dst_reg
, insn
->off
,
4355 BPF_SIZE(insn
->code
), BPF_WRITE
, -1, true);
4362 /* When register 'regno' is used to read the stack (either directly or through
4363 * a helper function) make sure that it's within stack boundary and, depending
4364 * on the access type, that all elements of the stack are initialized.
4366 * 'off' includes 'regno->off', but not its dynamic part (if any).
4368 * All registers that have been spilled on the stack in the slots within the
4369 * read offsets are marked as read.
4371 static int check_stack_range_initialized(
4372 struct bpf_verifier_env
*env
, int regno
, int off
,
4373 int access_size
, bool zero_size_allowed
,
4374 enum stack_access_src type
, struct bpf_call_arg_meta
*meta
)
4376 struct bpf_reg_state
*reg
= reg_state(env
, regno
);
4377 struct bpf_func_state
*state
= func(env
, reg
);
4378 int err
, min_off
, max_off
, i
, j
, slot
, spi
;
4379 char *err_extra
= type
== ACCESS_HELPER
? " indirect" : "";
4380 enum bpf_access_type bounds_check_type
;
4381 /* Some accesses can write anything into the stack, others are
4384 bool clobber
= false;
4386 if (access_size
== 0 && !zero_size_allowed
) {
4387 verbose(env
, "invalid zero-sized read\n");
4391 if (type
== ACCESS_HELPER
) {
4392 /* The bounds checks for writes are more permissive than for
4393 * reads. However, if raw_mode is not set, we'll do extra
4396 bounds_check_type
= BPF_WRITE
;
4399 bounds_check_type
= BPF_READ
;
4401 err
= check_stack_access_within_bounds(env
, regno
, off
, access_size
,
4402 type
, bounds_check_type
);
4407 if (tnum_is_const(reg
->var_off
)) {
4408 min_off
= max_off
= reg
->var_off
.value
+ off
;
4410 /* Variable offset is prohibited for unprivileged mode for
4411 * simplicity since it requires corresponding support in
4412 * Spectre masking for stack ALU.
4413 * See also retrieve_ptr_limit().
4415 if (!env
->bypass_spec_v1
) {
4418 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
4419 verbose(env
, "R%d%s variable offset stack access prohibited for !root, var_off=%s\n",
4420 regno
, err_extra
, tn_buf
);
4423 /* Only initialized buffer on stack is allowed to be accessed
4424 * with variable offset. With uninitialized buffer it's hard to
4425 * guarantee that whole memory is marked as initialized on
4426 * helper return since specific bounds are unknown what may
4427 * cause uninitialized stack leaking.
4429 if (meta
&& meta
->raw_mode
)
4432 min_off
= reg
->smin_value
+ off
;
4433 max_off
= reg
->smax_value
+ off
;
4436 if (meta
&& meta
->raw_mode
) {
4437 meta
->access_size
= access_size
;
4438 meta
->regno
= regno
;
4442 for (i
= min_off
; i
< max_off
+ access_size
; i
++) {
4446 spi
= slot
/ BPF_REG_SIZE
;
4447 if (state
->allocated_stack
<= slot
)
4449 stype
= &state
->stack
[spi
].slot_type
[slot
% BPF_REG_SIZE
];
4450 if (*stype
== STACK_MISC
)
4452 if (*stype
== STACK_ZERO
) {
4454 /* helper can write anything into the stack */
4455 *stype
= STACK_MISC
;
4460 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
4461 state
->stack
[spi
].spilled_ptr
.type
== PTR_TO_BTF_ID
)
4464 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
4465 (state
->stack
[spi
].spilled_ptr
.type
== SCALAR_VALUE
||
4466 env
->allow_ptr_leaks
)) {
4468 __mark_reg_unknown(env
, &state
->stack
[spi
].spilled_ptr
);
4469 for (j
= 0; j
< BPF_REG_SIZE
; j
++)
4470 state
->stack
[spi
].slot_type
[j
] = STACK_MISC
;
4476 if (tnum_is_const(reg
->var_off
)) {
4477 verbose(env
, "invalid%s read from stack R%d off %d+%d size %d\n",
4478 err_extra
, regno
, min_off
, i
- min_off
, access_size
);
4482 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
4483 verbose(env
, "invalid%s read from stack R%d var_off %s+%d size %d\n",
4484 err_extra
, regno
, tn_buf
, i
- min_off
, access_size
);
4488 /* reading any byte out of 8-byte 'spill_slot' will cause
4489 * the whole slot to be marked as 'read'
4491 mark_reg_read(env
, &state
->stack
[spi
].spilled_ptr
,
4492 state
->stack
[spi
].spilled_ptr
.parent
,
4495 return update_stack_depth(env
, state
, min_off
);
4498 static int check_helper_mem_access(struct bpf_verifier_env
*env
, int regno
,
4499 int access_size
, bool zero_size_allowed
,
4500 struct bpf_call_arg_meta
*meta
)
4502 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
4504 switch (reg
->type
) {
4506 case PTR_TO_PACKET_META
:
4507 return check_packet_access(env
, regno
, reg
->off
, access_size
,
4509 case PTR_TO_MAP_KEY
:
4510 return check_mem_region_access(env
, regno
, reg
->off
, access_size
,
4511 reg
->map_ptr
->key_size
, false);
4512 case PTR_TO_MAP_VALUE
:
4513 if (check_map_access_type(env
, regno
, reg
->off
, access_size
,
4514 meta
&& meta
->raw_mode
? BPF_WRITE
:
4517 return check_map_access(env
, regno
, reg
->off
, access_size
,
4520 return check_mem_region_access(env
, regno
, reg
->off
,
4521 access_size
, reg
->mem_size
,
4523 case PTR_TO_RDONLY_BUF
:
4524 if (meta
&& meta
->raw_mode
)
4526 return check_buffer_access(env
, reg
, regno
, reg
->off
,
4527 access_size
, zero_size_allowed
,
4529 &env
->prog
->aux
->max_rdonly_access
);
4530 case PTR_TO_RDWR_BUF
:
4531 return check_buffer_access(env
, reg
, regno
, reg
->off
,
4532 access_size
, zero_size_allowed
,
4534 &env
->prog
->aux
->max_rdwr_access
);
4536 return check_stack_range_initialized(
4538 regno
, reg
->off
, access_size
,
4539 zero_size_allowed
, ACCESS_HELPER
, meta
);
4540 default: /* scalar_value or invalid ptr */
4541 /* Allow zero-byte read from NULL, regardless of pointer type */
4542 if (zero_size_allowed
&& access_size
== 0 &&
4543 register_is_null(reg
))
4546 verbose(env
, "R%d type=%s expected=%s\n", regno
,
4547 reg_type_str
[reg
->type
],
4548 reg_type_str
[PTR_TO_STACK
]);
4553 int check_mem_reg(struct bpf_verifier_env
*env
, struct bpf_reg_state
*reg
,
4554 u32 regno
, u32 mem_size
)
4556 if (register_is_null(reg
))
4559 if (reg_type_may_be_null(reg
->type
)) {
4560 /* Assuming that the register contains a value check if the memory
4561 * access is safe. Temporarily save and restore the register's state as
4562 * the conversion shouldn't be visible to a caller.
4564 const struct bpf_reg_state saved_reg
= *reg
;
4567 mark_ptr_not_null_reg(reg
);
4568 rv
= check_helper_mem_access(env
, regno
, mem_size
, true, NULL
);
4573 return check_helper_mem_access(env
, regno
, mem_size
, true, NULL
);
4576 /* Implementation details:
4577 * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL
4578 * Two bpf_map_lookups (even with the same key) will have different reg->id.
4579 * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after
4580 * value_or_null->value transition, since the verifier only cares about
4581 * the range of access to valid map value pointer and doesn't care about actual
4582 * address of the map element.
4583 * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
4584 * reg->id > 0 after value_or_null->value transition. By doing so
4585 * two bpf_map_lookups will be considered two different pointers that
4586 * point to different bpf_spin_locks.
4587 * The verifier allows taking only one bpf_spin_lock at a time to avoid
4589 * Since only one bpf_spin_lock is allowed the checks are simpler than
4590 * reg_is_refcounted() logic. The verifier needs to remember only
4591 * one spin_lock instead of array of acquired_refs.
4592 * cur_state->active_spin_lock remembers which map value element got locked
4593 * and clears it after bpf_spin_unlock.
4595 static int process_spin_lock(struct bpf_verifier_env
*env
, int regno
,
4598 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
4599 struct bpf_verifier_state
*cur
= env
->cur_state
;
4600 bool is_const
= tnum_is_const(reg
->var_off
);
4601 struct bpf_map
*map
= reg
->map_ptr
;
4602 u64 val
= reg
->var_off
.value
;
4606 "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
4612 "map '%s' has to have BTF in order to use bpf_spin_lock\n",
4616 if (!map_value_has_spin_lock(map
)) {
4617 if (map
->spin_lock_off
== -E2BIG
)
4619 "map '%s' has more than one 'struct bpf_spin_lock'\n",
4621 else if (map
->spin_lock_off
== -ENOENT
)
4623 "map '%s' doesn't have 'struct bpf_spin_lock'\n",
4627 "map '%s' is not a struct type or bpf_spin_lock is mangled\n",
4631 if (map
->spin_lock_off
!= val
+ reg
->off
) {
4632 verbose(env
, "off %lld doesn't point to 'struct bpf_spin_lock'\n",
4637 if (cur
->active_spin_lock
) {
4639 "Locking two bpf_spin_locks are not allowed\n");
4642 cur
->active_spin_lock
= reg
->id
;
4644 if (!cur
->active_spin_lock
) {
4645 verbose(env
, "bpf_spin_unlock without taking a lock\n");
4648 if (cur
->active_spin_lock
!= reg
->id
) {
4649 verbose(env
, "bpf_spin_unlock of different lock\n");
4652 cur
->active_spin_lock
= 0;
4657 static bool arg_type_is_mem_ptr(enum bpf_arg_type type
)
4659 return type
== ARG_PTR_TO_MEM
||
4660 type
== ARG_PTR_TO_MEM_OR_NULL
||
4661 type
== ARG_PTR_TO_UNINIT_MEM
;
4664 static bool arg_type_is_mem_size(enum bpf_arg_type type
)
4666 return type
== ARG_CONST_SIZE
||
4667 type
== ARG_CONST_SIZE_OR_ZERO
;
4670 static bool arg_type_is_alloc_size(enum bpf_arg_type type
)
4672 return type
== ARG_CONST_ALLOC_SIZE_OR_ZERO
;
4675 static bool arg_type_is_int_ptr(enum bpf_arg_type type
)
4677 return type
== ARG_PTR_TO_INT
||
4678 type
== ARG_PTR_TO_LONG
;
4681 static int int_ptr_type_to_size(enum bpf_arg_type type
)
4683 if (type
== ARG_PTR_TO_INT
)
4685 else if (type
== ARG_PTR_TO_LONG
)
4691 static int resolve_map_arg_type(struct bpf_verifier_env
*env
,
4692 const struct bpf_call_arg_meta
*meta
,
4693 enum bpf_arg_type
*arg_type
)
4695 if (!meta
->map_ptr
) {
4696 /* kernel subsystem misconfigured verifier */
4697 verbose(env
, "invalid map_ptr to access map->type\n");
4701 switch (meta
->map_ptr
->map_type
) {
4702 case BPF_MAP_TYPE_SOCKMAP
:
4703 case BPF_MAP_TYPE_SOCKHASH
:
4704 if (*arg_type
== ARG_PTR_TO_MAP_VALUE
) {
4705 *arg_type
= ARG_PTR_TO_BTF_ID_SOCK_COMMON
;
4707 verbose(env
, "invalid arg_type for sockmap/sockhash\n");
4718 struct bpf_reg_types
{
4719 const enum bpf_reg_type types
[10];
4723 static const struct bpf_reg_types map_key_value_types
= {
4733 static const struct bpf_reg_types sock_types
= {
4743 static const struct bpf_reg_types btf_id_sock_common_types
= {
4751 .btf_id
= &btf_sock_ids
[BTF_SOCK_TYPE_SOCK_COMMON
],
4755 static const struct bpf_reg_types mem_types
= {
4768 static const struct bpf_reg_types int_ptr_types
= {
4778 static const struct bpf_reg_types fullsock_types
= { .types
= { PTR_TO_SOCKET
} };
4779 static const struct bpf_reg_types scalar_types
= { .types
= { SCALAR_VALUE
} };
4780 static const struct bpf_reg_types context_types
= { .types
= { PTR_TO_CTX
} };
4781 static const struct bpf_reg_types alloc_mem_types
= { .types
= { PTR_TO_MEM
} };
4782 static const struct bpf_reg_types const_map_ptr_types
= { .types
= { CONST_PTR_TO_MAP
} };
4783 static const struct bpf_reg_types btf_ptr_types
= { .types
= { PTR_TO_BTF_ID
} };
4784 static const struct bpf_reg_types spin_lock_types
= { .types
= { PTR_TO_MAP_VALUE
} };
4785 static const struct bpf_reg_types percpu_btf_ptr_types
= { .types
= { PTR_TO_PERCPU_BTF_ID
} };
4786 static const struct bpf_reg_types func_ptr_types
= { .types
= { PTR_TO_FUNC
} };
4787 static const struct bpf_reg_types stack_ptr_types
= { .types
= { PTR_TO_STACK
} };
4788 static const struct bpf_reg_types const_str_ptr_types
= { .types
= { PTR_TO_MAP_VALUE
} };
4790 static const struct bpf_reg_types
*compatible_reg_types
[__BPF_ARG_TYPE_MAX
] = {
4791 [ARG_PTR_TO_MAP_KEY
] = &map_key_value_types
,
4792 [ARG_PTR_TO_MAP_VALUE
] = &map_key_value_types
,
4793 [ARG_PTR_TO_UNINIT_MAP_VALUE
] = &map_key_value_types
,
4794 [ARG_PTR_TO_MAP_VALUE_OR_NULL
] = &map_key_value_types
,
4795 [ARG_CONST_SIZE
] = &scalar_types
,
4796 [ARG_CONST_SIZE_OR_ZERO
] = &scalar_types
,
4797 [ARG_CONST_ALLOC_SIZE_OR_ZERO
] = &scalar_types
,
4798 [ARG_CONST_MAP_PTR
] = &const_map_ptr_types
,
4799 [ARG_PTR_TO_CTX
] = &context_types
,
4800 [ARG_PTR_TO_CTX_OR_NULL
] = &context_types
,
4801 [ARG_PTR_TO_SOCK_COMMON
] = &sock_types
,
4803 [ARG_PTR_TO_BTF_ID_SOCK_COMMON
] = &btf_id_sock_common_types
,
4805 [ARG_PTR_TO_SOCKET
] = &fullsock_types
,
4806 [ARG_PTR_TO_SOCKET_OR_NULL
] = &fullsock_types
,
4807 [ARG_PTR_TO_BTF_ID
] = &btf_ptr_types
,
4808 [ARG_PTR_TO_SPIN_LOCK
] = &spin_lock_types
,
4809 [ARG_PTR_TO_MEM
] = &mem_types
,
4810 [ARG_PTR_TO_MEM_OR_NULL
] = &mem_types
,
4811 [ARG_PTR_TO_UNINIT_MEM
] = &mem_types
,
4812 [ARG_PTR_TO_ALLOC_MEM
] = &alloc_mem_types
,
4813 [ARG_PTR_TO_ALLOC_MEM_OR_NULL
] = &alloc_mem_types
,
4814 [ARG_PTR_TO_INT
] = &int_ptr_types
,
4815 [ARG_PTR_TO_LONG
] = &int_ptr_types
,
4816 [ARG_PTR_TO_PERCPU_BTF_ID
] = &percpu_btf_ptr_types
,
4817 [ARG_PTR_TO_FUNC
] = &func_ptr_types
,
4818 [ARG_PTR_TO_STACK_OR_NULL
] = &stack_ptr_types
,
4819 [ARG_PTR_TO_CONST_STR
] = &const_str_ptr_types
,
4822 static int check_reg_type(struct bpf_verifier_env
*env
, u32 regno
,
4823 enum bpf_arg_type arg_type
,
4824 const u32
*arg_btf_id
)
4826 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
4827 enum bpf_reg_type expected
, type
= reg
->type
;
4828 const struct bpf_reg_types
*compatible
;
4831 compatible
= compatible_reg_types
[arg_type
];
4833 verbose(env
, "verifier internal error: unsupported arg type %d\n", arg_type
);
4837 for (i
= 0; i
< ARRAY_SIZE(compatible
->types
); i
++) {
4838 expected
= compatible
->types
[i
];
4839 if (expected
== NOT_INIT
)
4842 if (type
== expected
)
4846 verbose(env
, "R%d type=%s expected=", regno
, reg_type_str
[type
]);
4847 for (j
= 0; j
+ 1 < i
; j
++)
4848 verbose(env
, "%s, ", reg_type_str
[compatible
->types
[j
]]);
4849 verbose(env
, "%s\n", reg_type_str
[compatible
->types
[j
]]);
4853 if (type
== PTR_TO_BTF_ID
) {
4855 if (!compatible
->btf_id
) {
4856 verbose(env
, "verifier internal error: missing arg compatible BTF ID\n");
4859 arg_btf_id
= compatible
->btf_id
;
4862 if (!btf_struct_ids_match(&env
->log
, reg
->btf
, reg
->btf_id
, reg
->off
,
4863 btf_vmlinux
, *arg_btf_id
)) {
4864 verbose(env
, "R%d is of type %s but %s is expected\n",
4865 regno
, kernel_type_name(reg
->btf
, reg
->btf_id
),
4866 kernel_type_name(btf_vmlinux
, *arg_btf_id
));
4870 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
4871 verbose(env
, "R%d is a pointer to in-kernel struct with non-zero offset\n",
4880 static int check_func_arg(struct bpf_verifier_env
*env
, u32 arg
,
4881 struct bpf_call_arg_meta
*meta
,
4882 const struct bpf_func_proto
*fn
)
4884 u32 regno
= BPF_REG_1
+ arg
;
4885 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
4886 enum bpf_arg_type arg_type
= fn
->arg_type
[arg
];
4887 enum bpf_reg_type type
= reg
->type
;
4890 if (arg_type
== ARG_DONTCARE
)
4893 err
= check_reg_arg(env
, regno
, SRC_OP
);
4897 if (arg_type
== ARG_ANYTHING
) {
4898 if (is_pointer_value(env
, regno
)) {
4899 verbose(env
, "R%d leaks addr into helper function\n",
4906 if (type_is_pkt_pointer(type
) &&
4907 !may_access_direct_pkt_data(env
, meta
, BPF_READ
)) {
4908 verbose(env
, "helper access to the packet is not allowed\n");
4912 if (arg_type
== ARG_PTR_TO_MAP_VALUE
||
4913 arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
||
4914 arg_type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
) {
4915 err
= resolve_map_arg_type(env
, meta
, &arg_type
);
4920 if (register_is_null(reg
) && arg_type_may_be_null(arg_type
))
4921 /* A NULL register has a SCALAR_VALUE type, so skip
4924 goto skip_type_check
;
4926 err
= check_reg_type(env
, regno
, arg_type
, fn
->arg_btf_id
[arg
]);
4930 if (type
== PTR_TO_CTX
) {
4931 err
= check_ctx_reg(env
, reg
, regno
);
4937 if (reg
->ref_obj_id
) {
4938 if (meta
->ref_obj_id
) {
4939 verbose(env
, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
4940 regno
, reg
->ref_obj_id
,
4944 meta
->ref_obj_id
= reg
->ref_obj_id
;
4947 if (arg_type
== ARG_CONST_MAP_PTR
) {
4948 /* bpf_map_xxx(map_ptr) call: remember that map_ptr */
4949 meta
->map_ptr
= reg
->map_ptr
;
4950 } else if (arg_type
== ARG_PTR_TO_MAP_KEY
) {
4951 /* bpf_map_xxx(..., map_ptr, ..., key) call:
4952 * check that [key, key + map->key_size) are within
4953 * stack limits and initialized
4955 if (!meta
->map_ptr
) {
4956 /* in function declaration map_ptr must come before
4957 * map_key, so that it's verified and known before
4958 * we have to check map_key here. Otherwise it means
4959 * that kernel subsystem misconfigured verifier
4961 verbose(env
, "invalid map_ptr to access map->key\n");
4964 err
= check_helper_mem_access(env
, regno
,
4965 meta
->map_ptr
->key_size
, false,
4967 } else if (arg_type
== ARG_PTR_TO_MAP_VALUE
||
4968 (arg_type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
&&
4969 !register_is_null(reg
)) ||
4970 arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
) {
4971 /* bpf_map_xxx(..., map_ptr, ..., value) call:
4972 * check [value, value + map->value_size) validity
4974 if (!meta
->map_ptr
) {
4975 /* kernel subsystem misconfigured verifier */
4976 verbose(env
, "invalid map_ptr to access map->value\n");
4979 meta
->raw_mode
= (arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
);
4980 err
= check_helper_mem_access(env
, regno
,
4981 meta
->map_ptr
->value_size
, false,
4983 } else if (arg_type
== ARG_PTR_TO_PERCPU_BTF_ID
) {
4985 verbose(env
, "Helper has invalid btf_id in R%d\n", regno
);
4988 meta
->ret_btf
= reg
->btf
;
4989 meta
->ret_btf_id
= reg
->btf_id
;
4990 } else if (arg_type
== ARG_PTR_TO_SPIN_LOCK
) {
4991 if (meta
->func_id
== BPF_FUNC_spin_lock
) {
4992 if (process_spin_lock(env
, regno
, true))
4994 } else if (meta
->func_id
== BPF_FUNC_spin_unlock
) {
4995 if (process_spin_lock(env
, regno
, false))
4998 verbose(env
, "verifier internal error\n");
5001 } else if (arg_type
== ARG_PTR_TO_FUNC
) {
5002 meta
->subprogno
= reg
->subprogno
;
5003 } else if (arg_type_is_mem_ptr(arg_type
)) {
5004 /* The access to this pointer is only checked when we hit the
5005 * next is_mem_size argument below.
5007 meta
->raw_mode
= (arg_type
== ARG_PTR_TO_UNINIT_MEM
);
5008 } else if (arg_type_is_mem_size(arg_type
)) {
5009 bool zero_size_allowed
= (arg_type
== ARG_CONST_SIZE_OR_ZERO
);
5011 /* This is used to refine r0 return value bounds for helpers
5012 * that enforce this value as an upper bound on return values.
5013 * See do_refine_retval_range() for helpers that can refine
5014 * the return value. C type of helper is u32 so we pull register
5015 * bound from umax_value however, if negative verifier errors
5016 * out. Only upper bounds can be learned because retval is an
5017 * int type and negative retvals are allowed.
5019 meta
->msize_max_value
= reg
->umax_value
;
5021 /* The register is SCALAR_VALUE; the access check
5022 * happens using its boundaries.
5024 if (!tnum_is_const(reg
->var_off
))
5025 /* For unprivileged variable accesses, disable raw
5026 * mode so that the program is required to
5027 * initialize all the memory that the helper could
5028 * just partially fill up.
5032 if (reg
->smin_value
< 0) {
5033 verbose(env
, "R%d min value is negative, either use unsigned or 'var &= const'\n",
5038 if (reg
->umin_value
== 0) {
5039 err
= check_helper_mem_access(env
, regno
- 1, 0,
5046 if (reg
->umax_value
>= BPF_MAX_VAR_SIZ
) {
5047 verbose(env
, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
5051 err
= check_helper_mem_access(env
, regno
- 1,
5053 zero_size_allowed
, meta
);
5055 err
= mark_chain_precision(env
, regno
);
5056 } else if (arg_type_is_alloc_size(arg_type
)) {
5057 if (!tnum_is_const(reg
->var_off
)) {
5058 verbose(env
, "R%d is not a known constant'\n",
5062 meta
->mem_size
= reg
->var_off
.value
;
5063 } else if (arg_type_is_int_ptr(arg_type
)) {
5064 int size
= int_ptr_type_to_size(arg_type
);
5066 err
= check_helper_mem_access(env
, regno
, size
, false, meta
);
5069 err
= check_ptr_alignment(env
, reg
, 0, size
, true);
5070 } else if (arg_type
== ARG_PTR_TO_CONST_STR
) {
5071 struct bpf_map
*map
= reg
->map_ptr
;
5076 if (!bpf_map_is_rdonly(map
)) {
5077 verbose(env
, "R%d does not point to a readonly map'\n", regno
);
5081 if (!tnum_is_const(reg
->var_off
)) {
5082 verbose(env
, "R%d is not a constant address'\n", regno
);
5086 if (!map
->ops
->map_direct_value_addr
) {
5087 verbose(env
, "no direct value access support for this map type\n");
5091 err
= check_map_access(env
, regno
, reg
->off
,
5092 map
->value_size
- reg
->off
, false);
5096 map_off
= reg
->off
+ reg
->var_off
.value
;
5097 err
= map
->ops
->map_direct_value_addr(map
, &map_addr
, map_off
);
5099 verbose(env
, "direct value access on string failed\n");
5103 str_ptr
= (char *)(long)(map_addr
);
5104 if (!strnchr(str_ptr
+ map_off
, map
->value_size
- map_off
, 0)) {
5105 verbose(env
, "string is not zero-terminated\n");
5113 static bool may_update_sockmap(struct bpf_verifier_env
*env
, int func_id
)
5115 enum bpf_attach_type eatype
= env
->prog
->expected_attach_type
;
5116 enum bpf_prog_type type
= resolve_prog_type(env
->prog
);
5118 if (func_id
!= BPF_FUNC_map_update_elem
)
5121 /* It's not possible to get access to a locked struct sock in these
5122 * contexts, so updating is safe.
5125 case BPF_PROG_TYPE_TRACING
:
5126 if (eatype
== BPF_TRACE_ITER
)
5129 case BPF_PROG_TYPE_SOCKET_FILTER
:
5130 case BPF_PROG_TYPE_SCHED_CLS
:
5131 case BPF_PROG_TYPE_SCHED_ACT
:
5132 case BPF_PROG_TYPE_XDP
:
5133 case BPF_PROG_TYPE_SK_REUSEPORT
:
5134 case BPF_PROG_TYPE_FLOW_DISSECTOR
:
5135 case BPF_PROG_TYPE_SK_LOOKUP
:
5141 verbose(env
, "cannot update sockmap in this context\n");
5145 static bool allow_tail_call_in_subprogs(struct bpf_verifier_env
*env
)
5147 return env
->prog
->jit_requested
&& IS_ENABLED(CONFIG_X86_64
);
5150 static int check_map_func_compatibility(struct bpf_verifier_env
*env
,
5151 struct bpf_map
*map
, int func_id
)
5156 /* We need a two way check, first is from map perspective ... */
5157 switch (map
->map_type
) {
5158 case BPF_MAP_TYPE_PROG_ARRAY
:
5159 if (func_id
!= BPF_FUNC_tail_call
)
5162 case BPF_MAP_TYPE_PERF_EVENT_ARRAY
:
5163 if (func_id
!= BPF_FUNC_perf_event_read
&&
5164 func_id
!= BPF_FUNC_perf_event_output
&&
5165 func_id
!= BPF_FUNC_skb_output
&&
5166 func_id
!= BPF_FUNC_perf_event_read_value
&&
5167 func_id
!= BPF_FUNC_xdp_output
)
5170 case BPF_MAP_TYPE_RINGBUF
:
5171 if (func_id
!= BPF_FUNC_ringbuf_output
&&
5172 func_id
!= BPF_FUNC_ringbuf_reserve
&&
5173 func_id
!= BPF_FUNC_ringbuf_submit
&&
5174 func_id
!= BPF_FUNC_ringbuf_discard
&&
5175 func_id
!= BPF_FUNC_ringbuf_query
)
5178 case BPF_MAP_TYPE_STACK_TRACE
:
5179 if (func_id
!= BPF_FUNC_get_stackid
)
5182 case BPF_MAP_TYPE_CGROUP_ARRAY
:
5183 if (func_id
!= BPF_FUNC_skb_under_cgroup
&&
5184 func_id
!= BPF_FUNC_current_task_under_cgroup
)
5187 case BPF_MAP_TYPE_CGROUP_STORAGE
:
5188 case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
:
5189 if (func_id
!= BPF_FUNC_get_local_storage
)
5192 case BPF_MAP_TYPE_DEVMAP
:
5193 case BPF_MAP_TYPE_DEVMAP_HASH
:
5194 if (func_id
!= BPF_FUNC_redirect_map
&&
5195 func_id
!= BPF_FUNC_map_lookup_elem
)
5198 /* Restrict bpf side of cpumap and xskmap, open when use-cases
5201 case BPF_MAP_TYPE_CPUMAP
:
5202 if (func_id
!= BPF_FUNC_redirect_map
)
5205 case BPF_MAP_TYPE_XSKMAP
:
5206 if (func_id
!= BPF_FUNC_redirect_map
&&
5207 func_id
!= BPF_FUNC_map_lookup_elem
)
5210 case BPF_MAP_TYPE_ARRAY_OF_MAPS
:
5211 case BPF_MAP_TYPE_HASH_OF_MAPS
:
5212 if (func_id
!= BPF_FUNC_map_lookup_elem
)
5215 case BPF_MAP_TYPE_SOCKMAP
:
5216 if (func_id
!= BPF_FUNC_sk_redirect_map
&&
5217 func_id
!= BPF_FUNC_sock_map_update
&&
5218 func_id
!= BPF_FUNC_map_delete_elem
&&
5219 func_id
!= BPF_FUNC_msg_redirect_map
&&
5220 func_id
!= BPF_FUNC_sk_select_reuseport
&&
5221 func_id
!= BPF_FUNC_map_lookup_elem
&&
5222 !may_update_sockmap(env
, func_id
))
5225 case BPF_MAP_TYPE_SOCKHASH
:
5226 if (func_id
!= BPF_FUNC_sk_redirect_hash
&&
5227 func_id
!= BPF_FUNC_sock_hash_update
&&
5228 func_id
!= BPF_FUNC_map_delete_elem
&&
5229 func_id
!= BPF_FUNC_msg_redirect_hash
&&
5230 func_id
!= BPF_FUNC_sk_select_reuseport
&&
5231 func_id
!= BPF_FUNC_map_lookup_elem
&&
5232 !may_update_sockmap(env
, func_id
))
5235 case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY
:
5236 if (func_id
!= BPF_FUNC_sk_select_reuseport
)
5239 case BPF_MAP_TYPE_QUEUE
:
5240 case BPF_MAP_TYPE_STACK
:
5241 if (func_id
!= BPF_FUNC_map_peek_elem
&&
5242 func_id
!= BPF_FUNC_map_pop_elem
&&
5243 func_id
!= BPF_FUNC_map_push_elem
)
5246 case BPF_MAP_TYPE_SK_STORAGE
:
5247 if (func_id
!= BPF_FUNC_sk_storage_get
&&
5248 func_id
!= BPF_FUNC_sk_storage_delete
)
5251 case BPF_MAP_TYPE_INODE_STORAGE
:
5252 if (func_id
!= BPF_FUNC_inode_storage_get
&&
5253 func_id
!= BPF_FUNC_inode_storage_delete
)
5256 case BPF_MAP_TYPE_TASK_STORAGE
:
5257 if (func_id
!= BPF_FUNC_task_storage_get
&&
5258 func_id
!= BPF_FUNC_task_storage_delete
)
5265 /* ... and second from the function itself. */
5267 case BPF_FUNC_tail_call
:
5268 if (map
->map_type
!= BPF_MAP_TYPE_PROG_ARRAY
)
5270 if (env
->subprog_cnt
> 1 && !allow_tail_call_in_subprogs(env
)) {
5271 verbose(env
, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
5275 case BPF_FUNC_perf_event_read
:
5276 case BPF_FUNC_perf_event_output
:
5277 case BPF_FUNC_perf_event_read_value
:
5278 case BPF_FUNC_skb_output
:
5279 case BPF_FUNC_xdp_output
:
5280 if (map
->map_type
!= BPF_MAP_TYPE_PERF_EVENT_ARRAY
)
5283 case BPF_FUNC_get_stackid
:
5284 if (map
->map_type
!= BPF_MAP_TYPE_STACK_TRACE
)
5287 case BPF_FUNC_current_task_under_cgroup
:
5288 case BPF_FUNC_skb_under_cgroup
:
5289 if (map
->map_type
!= BPF_MAP_TYPE_CGROUP_ARRAY
)
5292 case BPF_FUNC_redirect_map
:
5293 if (map
->map_type
!= BPF_MAP_TYPE_DEVMAP
&&
5294 map
->map_type
!= BPF_MAP_TYPE_DEVMAP_HASH
&&
5295 map
->map_type
!= BPF_MAP_TYPE_CPUMAP
&&
5296 map
->map_type
!= BPF_MAP_TYPE_XSKMAP
)
5299 case BPF_FUNC_sk_redirect_map
:
5300 case BPF_FUNC_msg_redirect_map
:
5301 case BPF_FUNC_sock_map_update
:
5302 if (map
->map_type
!= BPF_MAP_TYPE_SOCKMAP
)
5305 case BPF_FUNC_sk_redirect_hash
:
5306 case BPF_FUNC_msg_redirect_hash
:
5307 case BPF_FUNC_sock_hash_update
:
5308 if (map
->map_type
!= BPF_MAP_TYPE_SOCKHASH
)
5311 case BPF_FUNC_get_local_storage
:
5312 if (map
->map_type
!= BPF_MAP_TYPE_CGROUP_STORAGE
&&
5313 map
->map_type
!= BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
)
5316 case BPF_FUNC_sk_select_reuseport
:
5317 if (map
->map_type
!= BPF_MAP_TYPE_REUSEPORT_SOCKARRAY
&&
5318 map
->map_type
!= BPF_MAP_TYPE_SOCKMAP
&&
5319 map
->map_type
!= BPF_MAP_TYPE_SOCKHASH
)
5322 case BPF_FUNC_map_peek_elem
:
5323 case BPF_FUNC_map_pop_elem
:
5324 case BPF_FUNC_map_push_elem
:
5325 if (map
->map_type
!= BPF_MAP_TYPE_QUEUE
&&
5326 map
->map_type
!= BPF_MAP_TYPE_STACK
)
5329 case BPF_FUNC_sk_storage_get
:
5330 case BPF_FUNC_sk_storage_delete
:
5331 if (map
->map_type
!= BPF_MAP_TYPE_SK_STORAGE
)
5334 case BPF_FUNC_inode_storage_get
:
5335 case BPF_FUNC_inode_storage_delete
:
5336 if (map
->map_type
!= BPF_MAP_TYPE_INODE_STORAGE
)
5339 case BPF_FUNC_task_storage_get
:
5340 case BPF_FUNC_task_storage_delete
:
5341 if (map
->map_type
!= BPF_MAP_TYPE_TASK_STORAGE
)
5350 verbose(env
, "cannot pass map_type %d into func %s#%d\n",
5351 map
->map_type
, func_id_name(func_id
), func_id
);
5355 static bool check_raw_mode_ok(const struct bpf_func_proto
*fn
)
5359 if (fn
->arg1_type
== ARG_PTR_TO_UNINIT_MEM
)
5361 if (fn
->arg2_type
== ARG_PTR_TO_UNINIT_MEM
)
5363 if (fn
->arg3_type
== ARG_PTR_TO_UNINIT_MEM
)
5365 if (fn
->arg4_type
== ARG_PTR_TO_UNINIT_MEM
)
5367 if (fn
->arg5_type
== ARG_PTR_TO_UNINIT_MEM
)
5370 /* We only support one arg being in raw mode at the moment,
5371 * which is sufficient for the helper functions we have
5377 static bool check_args_pair_invalid(enum bpf_arg_type arg_curr
,
5378 enum bpf_arg_type arg_next
)
5380 return (arg_type_is_mem_ptr(arg_curr
) &&
5381 !arg_type_is_mem_size(arg_next
)) ||
5382 (!arg_type_is_mem_ptr(arg_curr
) &&
5383 arg_type_is_mem_size(arg_next
));
5386 static bool check_arg_pair_ok(const struct bpf_func_proto
*fn
)
5388 /* bpf_xxx(..., buf, len) call will access 'len'
5389 * bytes from memory 'buf'. Both arg types need
5390 * to be paired, so make sure there's no buggy
5391 * helper function specification.
5393 if (arg_type_is_mem_size(fn
->arg1_type
) ||
5394 arg_type_is_mem_ptr(fn
->arg5_type
) ||
5395 check_args_pair_invalid(fn
->arg1_type
, fn
->arg2_type
) ||
5396 check_args_pair_invalid(fn
->arg2_type
, fn
->arg3_type
) ||
5397 check_args_pair_invalid(fn
->arg3_type
, fn
->arg4_type
) ||
5398 check_args_pair_invalid(fn
->arg4_type
, fn
->arg5_type
))
5404 static bool check_refcount_ok(const struct bpf_func_proto
*fn
, int func_id
)
5408 if (arg_type_may_be_refcounted(fn
->arg1_type
))
5410 if (arg_type_may_be_refcounted(fn
->arg2_type
))
5412 if (arg_type_may_be_refcounted(fn
->arg3_type
))
5414 if (arg_type_may_be_refcounted(fn
->arg4_type
))
5416 if (arg_type_may_be_refcounted(fn
->arg5_type
))
5419 /* A reference acquiring function cannot acquire
5420 * another refcounted ptr.
5422 if (may_be_acquire_function(func_id
) && count
)
5425 /* We only support one arg being unreferenced at the moment,
5426 * which is sufficient for the helper functions we have right now.
5431 static bool check_btf_id_ok(const struct bpf_func_proto
*fn
)
5435 for (i
= 0; i
< ARRAY_SIZE(fn
->arg_type
); i
++) {
5436 if (fn
->arg_type
[i
] == ARG_PTR_TO_BTF_ID
&& !fn
->arg_btf_id
[i
])
5439 if (fn
->arg_type
[i
] != ARG_PTR_TO_BTF_ID
&& fn
->arg_btf_id
[i
])
5446 static int check_func_proto(const struct bpf_func_proto
*fn
, int func_id
)
5448 return check_raw_mode_ok(fn
) &&
5449 check_arg_pair_ok(fn
) &&
5450 check_btf_id_ok(fn
) &&
5451 check_refcount_ok(fn
, func_id
) ? 0 : -EINVAL
;
5454 /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
5455 * are now invalid, so turn them into unknown SCALAR_VALUE.
5457 static void __clear_all_pkt_pointers(struct bpf_verifier_env
*env
,
5458 struct bpf_func_state
*state
)
5460 struct bpf_reg_state
*regs
= state
->regs
, *reg
;
5463 for (i
= 0; i
< MAX_BPF_REG
; i
++)
5464 if (reg_is_pkt_pointer_any(®s
[i
]))
5465 mark_reg_unknown(env
, regs
, i
);
5467 bpf_for_each_spilled_reg(i
, state
, reg
) {
5470 if (reg_is_pkt_pointer_any(reg
))
5471 __mark_reg_unknown(env
, reg
);
5475 static void clear_all_pkt_pointers(struct bpf_verifier_env
*env
)
5477 struct bpf_verifier_state
*vstate
= env
->cur_state
;
5480 for (i
= 0; i
<= vstate
->curframe
; i
++)
5481 __clear_all_pkt_pointers(env
, vstate
->frame
[i
]);
5486 BEYOND_PKT_END
= -2,
5489 static void mark_pkt_end(struct bpf_verifier_state
*vstate
, int regn
, bool range_open
)
5491 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
5492 struct bpf_reg_state
*reg
= &state
->regs
[regn
];
5494 if (reg
->type
!= PTR_TO_PACKET
)
5495 /* PTR_TO_PACKET_META is not supported yet */
5498 /* The 'reg' is pkt > pkt_end or pkt >= pkt_end.
5499 * How far beyond pkt_end it goes is unknown.
5500 * if (!range_open) it's the case of pkt >= pkt_end
5501 * if (range_open) it's the case of pkt > pkt_end
5502 * hence this pointer is at least 1 byte bigger than pkt_end
5505 reg
->range
= BEYOND_PKT_END
;
5507 reg
->range
= AT_PKT_END
;
5510 static void release_reg_references(struct bpf_verifier_env
*env
,
5511 struct bpf_func_state
*state
,
5514 struct bpf_reg_state
*regs
= state
->regs
, *reg
;
5517 for (i
= 0; i
< MAX_BPF_REG
; i
++)
5518 if (regs
[i
].ref_obj_id
== ref_obj_id
)
5519 mark_reg_unknown(env
, regs
, i
);
5521 bpf_for_each_spilled_reg(i
, state
, reg
) {
5524 if (reg
->ref_obj_id
== ref_obj_id
)
5525 __mark_reg_unknown(env
, reg
);
5529 /* The pointer with the specified id has released its reference to kernel
5530 * resources. Identify all copies of the same pointer and clear the reference.
5532 static int release_reference(struct bpf_verifier_env
*env
,
5535 struct bpf_verifier_state
*vstate
= env
->cur_state
;
5539 err
= release_reference_state(cur_func(env
), ref_obj_id
);
5543 for (i
= 0; i
<= vstate
->curframe
; i
++)
5544 release_reg_references(env
, vstate
->frame
[i
], ref_obj_id
);
5549 static void clear_caller_saved_regs(struct bpf_verifier_env
*env
,
5550 struct bpf_reg_state
*regs
)
5554 /* after the call registers r0 - r5 were scratched */
5555 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
5556 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
5557 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
5561 typedef int (*set_callee_state_fn
)(struct bpf_verifier_env
*env
,
5562 struct bpf_func_state
*caller
,
5563 struct bpf_func_state
*callee
,
5566 static int __check_func_call(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
,
5567 int *insn_idx
, int subprog
,
5568 set_callee_state_fn set_callee_state_cb
)
5570 struct bpf_verifier_state
*state
= env
->cur_state
;
5571 struct bpf_func_info_aux
*func_info_aux
;
5572 struct bpf_func_state
*caller
, *callee
;
5574 bool is_global
= false;
5576 if (state
->curframe
+ 1 >= MAX_CALL_FRAMES
) {
5577 verbose(env
, "the call stack of %d frames is too deep\n",
5578 state
->curframe
+ 2);
5582 caller
= state
->frame
[state
->curframe
];
5583 if (state
->frame
[state
->curframe
+ 1]) {
5584 verbose(env
, "verifier bug. Frame %d already allocated\n",
5585 state
->curframe
+ 1);
5589 func_info_aux
= env
->prog
->aux
->func_info_aux
;
5591 is_global
= func_info_aux
[subprog
].linkage
== BTF_FUNC_GLOBAL
;
5592 err
= btf_check_subprog_arg_match(env
, subprog
, caller
->regs
);
5597 verbose(env
, "Caller passes invalid args into func#%d\n",
5601 if (env
->log
.level
& BPF_LOG_LEVEL
)
5603 "Func#%d is global and valid. Skipping.\n",
5605 clear_caller_saved_regs(env
, caller
->regs
);
5607 /* All global functions return a 64-bit SCALAR_VALUE */
5608 mark_reg_unknown(env
, caller
->regs
, BPF_REG_0
);
5609 caller
->regs
[BPF_REG_0
].subreg_def
= DEF_NOT_SUBREG
;
5611 /* continue with next insn after call */
5616 callee
= kzalloc(sizeof(*callee
), GFP_KERNEL
);
5619 state
->frame
[state
->curframe
+ 1] = callee
;
5621 /* callee cannot access r0, r6 - r9 for reading and has to write
5622 * into its own stack before reading from it.
5623 * callee can read/write into caller's stack
5625 init_func_state(env
, callee
,
5626 /* remember the callsite, it will be used by bpf_exit */
5627 *insn_idx
/* callsite */,
5628 state
->curframe
+ 1 /* frameno within this callchain */,
5629 subprog
/* subprog number within this prog */);
5631 /* Transfer references to the callee */
5632 err
= transfer_reference_state(callee
, caller
);
5636 err
= set_callee_state_cb(env
, caller
, callee
, *insn_idx
);
5640 clear_caller_saved_regs(env
, caller
->regs
);
5642 /* only increment it after check_reg_arg() finished */
5645 /* and go analyze first insn of the callee */
5646 *insn_idx
= env
->subprog_info
[subprog
].start
- 1;
5648 if (env
->log
.level
& BPF_LOG_LEVEL
) {
5649 verbose(env
, "caller:\n");
5650 print_verifier_state(env
, caller
);
5651 verbose(env
, "callee:\n");
5652 print_verifier_state(env
, callee
);
5657 int map_set_for_each_callback_args(struct bpf_verifier_env
*env
,
5658 struct bpf_func_state
*caller
,
5659 struct bpf_func_state
*callee
)
5661 /* bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn,
5662 * void *callback_ctx, u64 flags);
5663 * callback_fn(struct bpf_map *map, void *key, void *value,
5664 * void *callback_ctx);
5666 callee
->regs
[BPF_REG_1
] = caller
->regs
[BPF_REG_1
];
5668 callee
->regs
[BPF_REG_2
].type
= PTR_TO_MAP_KEY
;
5669 __mark_reg_known_zero(&callee
->regs
[BPF_REG_2
]);
5670 callee
->regs
[BPF_REG_2
].map_ptr
= caller
->regs
[BPF_REG_1
].map_ptr
;
5672 callee
->regs
[BPF_REG_3
].type
= PTR_TO_MAP_VALUE
;
5673 __mark_reg_known_zero(&callee
->regs
[BPF_REG_3
]);
5674 callee
->regs
[BPF_REG_3
].map_ptr
= caller
->regs
[BPF_REG_1
].map_ptr
;
5676 /* pointer to stack or null */
5677 callee
->regs
[BPF_REG_4
] = caller
->regs
[BPF_REG_3
];
5680 __mark_reg_not_init(env
, &callee
->regs
[BPF_REG_5
]);
5684 static int set_callee_state(struct bpf_verifier_env
*env
,
5685 struct bpf_func_state
*caller
,
5686 struct bpf_func_state
*callee
, int insn_idx
)
5690 /* copy r1 - r5 args that callee can access. The copy includes parent
5691 * pointers, which connects us up to the liveness chain
5693 for (i
= BPF_REG_1
; i
<= BPF_REG_5
; i
++)
5694 callee
->regs
[i
] = caller
->regs
[i
];
5698 static int check_func_call(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
,
5701 int subprog
, target_insn
;
5703 target_insn
= *insn_idx
+ insn
->imm
+ 1;
5704 subprog
= find_subprog(env
, target_insn
);
5706 verbose(env
, "verifier bug. No program starts at insn %d\n",
5711 return __check_func_call(env
, insn
, insn_idx
, subprog
, set_callee_state
);
5714 static int set_map_elem_callback_state(struct bpf_verifier_env
*env
,
5715 struct bpf_func_state
*caller
,
5716 struct bpf_func_state
*callee
,
5719 struct bpf_insn_aux_data
*insn_aux
= &env
->insn_aux_data
[insn_idx
];
5720 struct bpf_map
*map
;
5723 if (bpf_map_ptr_poisoned(insn_aux
)) {
5724 verbose(env
, "tail_call abusing map_ptr\n");
5728 map
= BPF_MAP_PTR(insn_aux
->map_ptr_state
);
5729 if (!map
->ops
->map_set_for_each_callback_args
||
5730 !map
->ops
->map_for_each_callback
) {
5731 verbose(env
, "callback function not allowed for map\n");
5735 err
= map
->ops
->map_set_for_each_callback_args(env
, caller
, callee
);
5739 callee
->in_callback_fn
= true;
5743 static int prepare_func_exit(struct bpf_verifier_env
*env
, int *insn_idx
)
5745 struct bpf_verifier_state
*state
= env
->cur_state
;
5746 struct bpf_func_state
*caller
, *callee
;
5747 struct bpf_reg_state
*r0
;
5750 callee
= state
->frame
[state
->curframe
];
5751 r0
= &callee
->regs
[BPF_REG_0
];
5752 if (r0
->type
== PTR_TO_STACK
) {
5753 /* technically it's ok to return caller's stack pointer
5754 * (or caller's caller's pointer) back to the caller,
5755 * since these pointers are valid. Only current stack
5756 * pointer will be invalid as soon as function exits,
5757 * but let's be conservative
5759 verbose(env
, "cannot return stack pointer to the caller\n");
5764 caller
= state
->frame
[state
->curframe
];
5765 if (callee
->in_callback_fn
) {
5766 /* enforce R0 return value range [0, 1]. */
5767 struct tnum range
= tnum_range(0, 1);
5769 if (r0
->type
!= SCALAR_VALUE
) {
5770 verbose(env
, "R0 not a scalar value\n");
5773 if (!tnum_in(range
, r0
->var_off
)) {
5774 verbose_invalid_scalar(env
, r0
, &range
, "callback return", "R0");
5778 /* return to the caller whatever r0 had in the callee */
5779 caller
->regs
[BPF_REG_0
] = *r0
;
5782 /* Transfer references to the caller */
5783 err
= transfer_reference_state(caller
, callee
);
5787 *insn_idx
= callee
->callsite
+ 1;
5788 if (env
->log
.level
& BPF_LOG_LEVEL
) {
5789 verbose(env
, "returning from callee:\n");
5790 print_verifier_state(env
, callee
);
5791 verbose(env
, "to caller at %d:\n", *insn_idx
);
5792 print_verifier_state(env
, caller
);
5794 /* clear everything in the callee */
5795 free_func_state(callee
);
5796 state
->frame
[state
->curframe
+ 1] = NULL
;
5800 static void do_refine_retval_range(struct bpf_reg_state
*regs
, int ret_type
,
5802 struct bpf_call_arg_meta
*meta
)
5804 struct bpf_reg_state
*ret_reg
= ®s
[BPF_REG_0
];
5806 if (ret_type
!= RET_INTEGER
||
5807 (func_id
!= BPF_FUNC_get_stack
&&
5808 func_id
!= BPF_FUNC_get_task_stack
&&
5809 func_id
!= BPF_FUNC_probe_read_str
&&
5810 func_id
!= BPF_FUNC_probe_read_kernel_str
&&
5811 func_id
!= BPF_FUNC_probe_read_user_str
))
5814 ret_reg
->smax_value
= meta
->msize_max_value
;
5815 ret_reg
->s32_max_value
= meta
->msize_max_value
;
5816 ret_reg
->smin_value
= -MAX_ERRNO
;
5817 ret_reg
->s32_min_value
= -MAX_ERRNO
;
5818 __reg_deduce_bounds(ret_reg
);
5819 __reg_bound_offset(ret_reg
);
5820 __update_reg_bounds(ret_reg
);
5824 record_func_map(struct bpf_verifier_env
*env
, struct bpf_call_arg_meta
*meta
,
5825 int func_id
, int insn_idx
)
5827 struct bpf_insn_aux_data
*aux
= &env
->insn_aux_data
[insn_idx
];
5828 struct bpf_map
*map
= meta
->map_ptr
;
5830 if (func_id
!= BPF_FUNC_tail_call
&&
5831 func_id
!= BPF_FUNC_map_lookup_elem
&&
5832 func_id
!= BPF_FUNC_map_update_elem
&&
5833 func_id
!= BPF_FUNC_map_delete_elem
&&
5834 func_id
!= BPF_FUNC_map_push_elem
&&
5835 func_id
!= BPF_FUNC_map_pop_elem
&&
5836 func_id
!= BPF_FUNC_map_peek_elem
&&
5837 func_id
!= BPF_FUNC_for_each_map_elem
&&
5838 func_id
!= BPF_FUNC_redirect_map
)
5842 verbose(env
, "kernel subsystem misconfigured verifier\n");
5846 /* In case of read-only, some additional restrictions
5847 * need to be applied in order to prevent altering the
5848 * state of the map from program side.
5850 if ((map
->map_flags
& BPF_F_RDONLY_PROG
) &&
5851 (func_id
== BPF_FUNC_map_delete_elem
||
5852 func_id
== BPF_FUNC_map_update_elem
||
5853 func_id
== BPF_FUNC_map_push_elem
||
5854 func_id
== BPF_FUNC_map_pop_elem
)) {
5855 verbose(env
, "write into map forbidden\n");
5859 if (!BPF_MAP_PTR(aux
->map_ptr_state
))
5860 bpf_map_ptr_store(aux
, meta
->map_ptr
,
5861 !meta
->map_ptr
->bypass_spec_v1
);
5862 else if (BPF_MAP_PTR(aux
->map_ptr_state
) != meta
->map_ptr
)
5863 bpf_map_ptr_store(aux
, BPF_MAP_PTR_POISON
,
5864 !meta
->map_ptr
->bypass_spec_v1
);
5869 record_func_key(struct bpf_verifier_env
*env
, struct bpf_call_arg_meta
*meta
,
5870 int func_id
, int insn_idx
)
5872 struct bpf_insn_aux_data
*aux
= &env
->insn_aux_data
[insn_idx
];
5873 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
;
5874 struct bpf_map
*map
= meta
->map_ptr
;
5879 if (func_id
!= BPF_FUNC_tail_call
)
5881 if (!map
|| map
->map_type
!= BPF_MAP_TYPE_PROG_ARRAY
) {
5882 verbose(env
, "kernel subsystem misconfigured verifier\n");
5886 range
= tnum_range(0, map
->max_entries
- 1);
5887 reg
= ®s
[BPF_REG_3
];
5889 if (!register_is_const(reg
) || !tnum_in(range
, reg
->var_off
)) {
5890 bpf_map_key_store(aux
, BPF_MAP_KEY_POISON
);
5894 err
= mark_chain_precision(env
, BPF_REG_3
);
5898 val
= reg
->var_off
.value
;
5899 if (bpf_map_key_unseen(aux
))
5900 bpf_map_key_store(aux
, val
);
5901 else if (!bpf_map_key_poisoned(aux
) &&
5902 bpf_map_key_immediate(aux
) != val
)
5903 bpf_map_key_store(aux
, BPF_MAP_KEY_POISON
);
5907 static int check_reference_leak(struct bpf_verifier_env
*env
)
5909 struct bpf_func_state
*state
= cur_func(env
);
5912 for (i
= 0; i
< state
->acquired_refs
; i
++) {
5913 verbose(env
, "Unreleased reference id=%d alloc_insn=%d\n",
5914 state
->refs
[i
].id
, state
->refs
[i
].insn_idx
);
5916 return state
->acquired_refs
? -EINVAL
: 0;
5919 static int check_bpf_snprintf_call(struct bpf_verifier_env
*env
,
5920 struct bpf_reg_state
*regs
)
5922 struct bpf_reg_state
*fmt_reg
= ®s
[BPF_REG_3
];
5923 struct bpf_reg_state
*data_len_reg
= ®s
[BPF_REG_5
];
5924 struct bpf_map
*fmt_map
= fmt_reg
->map_ptr
;
5925 int err
, fmt_map_off
, num_args
;
5929 /* data must be an array of u64 */
5930 if (data_len_reg
->var_off
.value
% 8)
5932 num_args
= data_len_reg
->var_off
.value
/ 8;
5934 /* fmt being ARG_PTR_TO_CONST_STR guarantees that var_off is const
5935 * and map_direct_value_addr is set.
5937 fmt_map_off
= fmt_reg
->off
+ fmt_reg
->var_off
.value
;
5938 err
= fmt_map
->ops
->map_direct_value_addr(fmt_map
, &fmt_addr
,
5941 verbose(env
, "verifier bug\n");
5944 fmt
= (char *)(long)fmt_addr
+ fmt_map_off
;
5946 /* We are also guaranteed that fmt+fmt_map_off is NULL terminated, we
5947 * can focus on validating the format specifiers.
5949 err
= bpf_bprintf_prepare(fmt
, UINT_MAX
, NULL
, NULL
, num_args
);
5951 verbose(env
, "Invalid format string\n");
5956 static int check_helper_call(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
,
5959 const struct bpf_func_proto
*fn
= NULL
;
5960 struct bpf_reg_state
*regs
;
5961 struct bpf_call_arg_meta meta
;
5962 int insn_idx
= *insn_idx_p
;
5964 int i
, err
, func_id
;
5966 /* find function prototype */
5967 func_id
= insn
->imm
;
5968 if (func_id
< 0 || func_id
>= __BPF_FUNC_MAX_ID
) {
5969 verbose(env
, "invalid func %s#%d\n", func_id_name(func_id
),
5974 if (env
->ops
->get_func_proto
)
5975 fn
= env
->ops
->get_func_proto(func_id
, env
->prog
);
5977 verbose(env
, "unknown func %s#%d\n", func_id_name(func_id
),
5982 /* eBPF programs must be GPL compatible to use GPL-ed functions */
5983 if (!env
->prog
->gpl_compatible
&& fn
->gpl_only
) {
5984 verbose(env
, "cannot call GPL-restricted function from non-GPL compatible program\n");
5988 if (fn
->allowed
&& !fn
->allowed(env
->prog
)) {
5989 verbose(env
, "helper call is not allowed in probe\n");
5993 /* With LD_ABS/IND some JITs save/restore skb from r1. */
5994 changes_data
= bpf_helper_changes_pkt_data(fn
->func
);
5995 if (changes_data
&& fn
->arg1_type
!= ARG_PTR_TO_CTX
) {
5996 verbose(env
, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
5997 func_id_name(func_id
), func_id
);
6001 memset(&meta
, 0, sizeof(meta
));
6002 meta
.pkt_access
= fn
->pkt_access
;
6004 err
= check_func_proto(fn
, func_id
);
6006 verbose(env
, "kernel subsystem misconfigured func %s#%d\n",
6007 func_id_name(func_id
), func_id
);
6011 meta
.func_id
= func_id
;
6013 for (i
= 0; i
< MAX_BPF_FUNC_REG_ARGS
; i
++) {
6014 err
= check_func_arg(env
, i
, &meta
, fn
);
6019 err
= record_func_map(env
, &meta
, func_id
, insn_idx
);
6023 err
= record_func_key(env
, &meta
, func_id
, insn_idx
);
6027 /* Mark slots with STACK_MISC in case of raw mode, stack offset
6028 * is inferred from register state.
6030 for (i
= 0; i
< meta
.access_size
; i
++) {
6031 err
= check_mem_access(env
, insn_idx
, meta
.regno
, i
, BPF_B
,
6032 BPF_WRITE
, -1, false);
6037 if (func_id
== BPF_FUNC_tail_call
) {
6038 err
= check_reference_leak(env
);
6040 verbose(env
, "tail_call would lead to reference leak\n");
6043 } else if (is_release_function(func_id
)) {
6044 err
= release_reference(env
, meta
.ref_obj_id
);
6046 verbose(env
, "func %s#%d reference has not been acquired before\n",
6047 func_id_name(func_id
), func_id
);
6052 regs
= cur_regs(env
);
6054 /* check that flags argument in get_local_storage(map, flags) is 0,
6055 * this is required because get_local_storage() can't return an error.
6057 if (func_id
== BPF_FUNC_get_local_storage
&&
6058 !register_is_null(®s
[BPF_REG_2
])) {
6059 verbose(env
, "get_local_storage() doesn't support non-zero flags\n");
6063 if (func_id
== BPF_FUNC_for_each_map_elem
) {
6064 err
= __check_func_call(env
, insn
, insn_idx_p
, meta
.subprogno
,
6065 set_map_elem_callback_state
);
6070 if (func_id
== BPF_FUNC_snprintf
) {
6071 err
= check_bpf_snprintf_call(env
, regs
);
6076 /* reset caller saved regs */
6077 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
6078 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
6079 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
6082 /* helper call returns 64-bit value. */
6083 regs
[BPF_REG_0
].subreg_def
= DEF_NOT_SUBREG
;
6085 /* update return register (already marked as written above) */
6086 if (fn
->ret_type
== RET_INTEGER
) {
6087 /* sets type to SCALAR_VALUE */
6088 mark_reg_unknown(env
, regs
, BPF_REG_0
);
6089 } else if (fn
->ret_type
== RET_VOID
) {
6090 regs
[BPF_REG_0
].type
= NOT_INIT
;
6091 } else if (fn
->ret_type
== RET_PTR_TO_MAP_VALUE_OR_NULL
||
6092 fn
->ret_type
== RET_PTR_TO_MAP_VALUE
) {
6093 /* There is no offset yet applied, variable or fixed */
6094 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
6095 /* remember map_ptr, so that check_map_access()
6096 * can check 'value_size' boundary of memory access
6097 * to map element returned from bpf_map_lookup_elem()
6099 if (meta
.map_ptr
== NULL
) {
6101 "kernel subsystem misconfigured verifier\n");
6104 regs
[BPF_REG_0
].map_ptr
= meta
.map_ptr
;
6105 if (fn
->ret_type
== RET_PTR_TO_MAP_VALUE
) {
6106 regs
[BPF_REG_0
].type
= PTR_TO_MAP_VALUE
;
6107 if (map_value_has_spin_lock(meta
.map_ptr
))
6108 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
6110 regs
[BPF_REG_0
].type
= PTR_TO_MAP_VALUE_OR_NULL
;
6112 } else if (fn
->ret_type
== RET_PTR_TO_SOCKET_OR_NULL
) {
6113 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
6114 regs
[BPF_REG_0
].type
= PTR_TO_SOCKET_OR_NULL
;
6115 } else if (fn
->ret_type
== RET_PTR_TO_SOCK_COMMON_OR_NULL
) {
6116 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
6117 regs
[BPF_REG_0
].type
= PTR_TO_SOCK_COMMON_OR_NULL
;
6118 } else if (fn
->ret_type
== RET_PTR_TO_TCP_SOCK_OR_NULL
) {
6119 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
6120 regs
[BPF_REG_0
].type
= PTR_TO_TCP_SOCK_OR_NULL
;
6121 } else if (fn
->ret_type
== RET_PTR_TO_ALLOC_MEM_OR_NULL
) {
6122 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
6123 regs
[BPF_REG_0
].type
= PTR_TO_MEM_OR_NULL
;
6124 regs
[BPF_REG_0
].mem_size
= meta
.mem_size
;
6125 } else if (fn
->ret_type
== RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL
||
6126 fn
->ret_type
== RET_PTR_TO_MEM_OR_BTF_ID
) {
6127 const struct btf_type
*t
;
6129 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
6130 t
= btf_type_skip_modifiers(meta
.ret_btf
, meta
.ret_btf_id
, NULL
);
6131 if (!btf_type_is_struct(t
)) {
6133 const struct btf_type
*ret
;
6136 /* resolve the type size of ksym. */
6137 ret
= btf_resolve_size(meta
.ret_btf
, t
, &tsize
);
6139 tname
= btf_name_by_offset(meta
.ret_btf
, t
->name_off
);
6140 verbose(env
, "unable to resolve the size of type '%s': %ld\n",
6141 tname
, PTR_ERR(ret
));
6144 regs
[BPF_REG_0
].type
=
6145 fn
->ret_type
== RET_PTR_TO_MEM_OR_BTF_ID
?
6146 PTR_TO_MEM
: PTR_TO_MEM_OR_NULL
;
6147 regs
[BPF_REG_0
].mem_size
= tsize
;
6149 regs
[BPF_REG_0
].type
=
6150 fn
->ret_type
== RET_PTR_TO_MEM_OR_BTF_ID
?
6151 PTR_TO_BTF_ID
: PTR_TO_BTF_ID_OR_NULL
;
6152 regs
[BPF_REG_0
].btf
= meta
.ret_btf
;
6153 regs
[BPF_REG_0
].btf_id
= meta
.ret_btf_id
;
6155 } else if (fn
->ret_type
== RET_PTR_TO_BTF_ID_OR_NULL
||
6156 fn
->ret_type
== RET_PTR_TO_BTF_ID
) {
6159 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
6160 regs
[BPF_REG_0
].type
= fn
->ret_type
== RET_PTR_TO_BTF_ID
?
6162 PTR_TO_BTF_ID_OR_NULL
;
6163 ret_btf_id
= *fn
->ret_btf_id
;
6164 if (ret_btf_id
== 0) {
6165 verbose(env
, "invalid return type %d of func %s#%d\n",
6166 fn
->ret_type
, func_id_name(func_id
), func_id
);
6169 /* current BPF helper definitions are only coming from
6170 * built-in code with type IDs from vmlinux BTF
6172 regs
[BPF_REG_0
].btf
= btf_vmlinux
;
6173 regs
[BPF_REG_0
].btf_id
= ret_btf_id
;
6175 verbose(env
, "unknown return type %d of func %s#%d\n",
6176 fn
->ret_type
, func_id_name(func_id
), func_id
);
6180 if (reg_type_may_be_null(regs
[BPF_REG_0
].type
))
6181 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
6183 if (is_ptr_cast_function(func_id
)) {
6184 /* For release_reference() */
6185 regs
[BPF_REG_0
].ref_obj_id
= meta
.ref_obj_id
;
6186 } else if (is_acquire_function(func_id
, meta
.map_ptr
)) {
6187 int id
= acquire_reference_state(env
, insn_idx
);
6191 /* For mark_ptr_or_null_reg() */
6192 regs
[BPF_REG_0
].id
= id
;
6193 /* For release_reference() */
6194 regs
[BPF_REG_0
].ref_obj_id
= id
;
6197 do_refine_retval_range(regs
, fn
->ret_type
, func_id
, &meta
);
6199 err
= check_map_func_compatibility(env
, meta
.map_ptr
, func_id
);
6203 if ((func_id
== BPF_FUNC_get_stack
||
6204 func_id
== BPF_FUNC_get_task_stack
) &&
6205 !env
->prog
->has_callchain_buf
) {
6206 const char *err_str
;
6208 #ifdef CONFIG_PERF_EVENTS
6209 err
= get_callchain_buffers(sysctl_perf_event_max_stack
);
6210 err_str
= "cannot get callchain buffer for func %s#%d\n";
6213 err_str
= "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
6216 verbose(env
, err_str
, func_id_name(func_id
), func_id
);
6220 env
->prog
->has_callchain_buf
= true;
6223 if (func_id
== BPF_FUNC_get_stackid
|| func_id
== BPF_FUNC_get_stack
)
6224 env
->prog
->call_get_stack
= true;
6227 clear_all_pkt_pointers(env
);
6231 /* mark_btf_func_reg_size() is used when the reg size is determined by
6232 * the BTF func_proto's return value size and argument.
6234 static void mark_btf_func_reg_size(struct bpf_verifier_env
*env
, u32 regno
,
6237 struct bpf_reg_state
*reg
= &cur_regs(env
)[regno
];
6239 if (regno
== BPF_REG_0
) {
6240 /* Function return value */
6241 reg
->live
|= REG_LIVE_WRITTEN
;
6242 reg
->subreg_def
= reg_size
== sizeof(u64
) ?
6243 DEF_NOT_SUBREG
: env
->insn_idx
+ 1;
6245 /* Function argument */
6246 if (reg_size
== sizeof(u64
)) {
6247 mark_insn_zext(env
, reg
);
6248 mark_reg_read(env
, reg
, reg
->parent
, REG_LIVE_READ64
);
6250 mark_reg_read(env
, reg
, reg
->parent
, REG_LIVE_READ32
);
6255 static int check_kfunc_call(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
6257 const struct btf_type
*t
, *func
, *func_proto
, *ptr_type
;
6258 struct bpf_reg_state
*regs
= cur_regs(env
);
6259 const char *func_name
, *ptr_type_name
;
6260 u32 i
, nargs
, func_id
, ptr_type_id
;
6261 const struct btf_param
*args
;
6264 func_id
= insn
->imm
;
6265 func
= btf_type_by_id(btf_vmlinux
, func_id
);
6266 func_name
= btf_name_by_offset(btf_vmlinux
, func
->name_off
);
6267 func_proto
= btf_type_by_id(btf_vmlinux
, func
->type
);
6269 if (!env
->ops
->check_kfunc_call
||
6270 !env
->ops
->check_kfunc_call(func_id
)) {
6271 verbose(env
, "calling kernel function %s is not allowed\n",
6276 /* Check the arguments */
6277 err
= btf_check_kfunc_arg_match(env
, btf_vmlinux
, func_id
, regs
);
6281 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++)
6282 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
6284 /* Check return type */
6285 t
= btf_type_skip_modifiers(btf_vmlinux
, func_proto
->type
, NULL
);
6286 if (btf_type_is_scalar(t
)) {
6287 mark_reg_unknown(env
, regs
, BPF_REG_0
);
6288 mark_btf_func_reg_size(env
, BPF_REG_0
, t
->size
);
6289 } else if (btf_type_is_ptr(t
)) {
6290 ptr_type
= btf_type_skip_modifiers(btf_vmlinux
, t
->type
,
6292 if (!btf_type_is_struct(ptr_type
)) {
6293 ptr_type_name
= btf_name_by_offset(btf_vmlinux
,
6294 ptr_type
->name_off
);
6295 verbose(env
, "kernel function %s returns pointer type %s %s is not supported\n",
6296 func_name
, btf_type_str(ptr_type
),
6300 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
6301 regs
[BPF_REG_0
].btf
= btf_vmlinux
;
6302 regs
[BPF_REG_0
].type
= PTR_TO_BTF_ID
;
6303 regs
[BPF_REG_0
].btf_id
= ptr_type_id
;
6304 mark_btf_func_reg_size(env
, BPF_REG_0
, sizeof(void *));
6305 } /* else { add_kfunc_call() ensures it is btf_type_is_void(t) } */
6307 nargs
= btf_type_vlen(func_proto
);
6308 args
= (const struct btf_param
*)(func_proto
+ 1);
6309 for (i
= 0; i
< nargs
; i
++) {
6312 t
= btf_type_skip_modifiers(btf_vmlinux
, args
[i
].type
, NULL
);
6313 if (btf_type_is_ptr(t
))
6314 mark_btf_func_reg_size(env
, regno
, sizeof(void *));
6316 /* scalar. ensured by btf_check_kfunc_arg_match() */
6317 mark_btf_func_reg_size(env
, regno
, t
->size
);
6323 static bool signed_add_overflows(s64 a
, s64 b
)
6325 /* Do the add in u64, where overflow is well-defined */
6326 s64 res
= (s64
)((u64
)a
+ (u64
)b
);
6333 static bool signed_add32_overflows(s32 a
, s32 b
)
6335 /* Do the add in u32, where overflow is well-defined */
6336 s32 res
= (s32
)((u32
)a
+ (u32
)b
);
6343 static bool signed_sub_overflows(s64 a
, s64 b
)
6345 /* Do the sub in u64, where overflow is well-defined */
6346 s64 res
= (s64
)((u64
)a
- (u64
)b
);
6353 static bool signed_sub32_overflows(s32 a
, s32 b
)
6355 /* Do the sub in u32, where overflow is well-defined */
6356 s32 res
= (s32
)((u32
)a
- (u32
)b
);
6363 static bool check_reg_sane_offset(struct bpf_verifier_env
*env
,
6364 const struct bpf_reg_state
*reg
,
6365 enum bpf_reg_type type
)
6367 bool known
= tnum_is_const(reg
->var_off
);
6368 s64 val
= reg
->var_off
.value
;
6369 s64 smin
= reg
->smin_value
;
6371 if (known
&& (val
>= BPF_MAX_VAR_OFF
|| val
<= -BPF_MAX_VAR_OFF
)) {
6372 verbose(env
, "math between %s pointer and %lld is not allowed\n",
6373 reg_type_str
[type
], val
);
6377 if (reg
->off
>= BPF_MAX_VAR_OFF
|| reg
->off
<= -BPF_MAX_VAR_OFF
) {
6378 verbose(env
, "%s pointer offset %d is not allowed\n",
6379 reg_type_str
[type
], reg
->off
);
6383 if (smin
== S64_MIN
) {
6384 verbose(env
, "math between %s pointer and register with unbounded min value is not allowed\n",
6385 reg_type_str
[type
]);
6389 if (smin
>= BPF_MAX_VAR_OFF
|| smin
<= -BPF_MAX_VAR_OFF
) {
6390 verbose(env
, "value %lld makes %s pointer be out of bounds\n",
6391 smin
, reg_type_str
[type
]);
6398 static struct bpf_insn_aux_data
*cur_aux(struct bpf_verifier_env
*env
)
6400 return &env
->insn_aux_data
[env
->insn_idx
];
6411 static int retrieve_ptr_limit(const struct bpf_reg_state
*ptr_reg
,
6412 u32
*alu_limit
, bool mask_to_left
)
6414 u32 max
= 0, ptr_limit
= 0;
6416 switch (ptr_reg
->type
) {
6418 /* Offset 0 is out-of-bounds, but acceptable start for the
6419 * left direction, see BPF_REG_FP. Also, unknown scalar
6420 * offset where we would need to deal with min/max bounds is
6421 * currently prohibited for unprivileged.
6423 max
= MAX_BPF_STACK
+ mask_to_left
;
6424 ptr_limit
= -(ptr_reg
->var_off
.value
+ ptr_reg
->off
);
6426 case PTR_TO_MAP_VALUE
:
6427 max
= ptr_reg
->map_ptr
->value_size
;
6428 ptr_limit
= (mask_to_left
?
6429 ptr_reg
->smin_value
:
6430 ptr_reg
->umax_value
) + ptr_reg
->off
;
6436 if (ptr_limit
>= max
)
6437 return REASON_LIMIT
;
6438 *alu_limit
= ptr_limit
;
6442 static bool can_skip_alu_sanitation(const struct bpf_verifier_env
*env
,
6443 const struct bpf_insn
*insn
)
6445 return env
->bypass_spec_v1
|| BPF_SRC(insn
->code
) == BPF_K
;
6448 static int update_alu_sanitation_state(struct bpf_insn_aux_data
*aux
,
6449 u32 alu_state
, u32 alu_limit
)
6451 /* If we arrived here from different branches with different
6452 * state or limits to sanitize, then this won't work.
6454 if (aux
->alu_state
&&
6455 (aux
->alu_state
!= alu_state
||
6456 aux
->alu_limit
!= alu_limit
))
6457 return REASON_PATHS
;
6459 /* Corresponding fixup done in do_misc_fixups(). */
6460 aux
->alu_state
= alu_state
;
6461 aux
->alu_limit
= alu_limit
;
6465 static int sanitize_val_alu(struct bpf_verifier_env
*env
,
6466 struct bpf_insn
*insn
)
6468 struct bpf_insn_aux_data
*aux
= cur_aux(env
);
6470 if (can_skip_alu_sanitation(env
, insn
))
6473 return update_alu_sanitation_state(aux
, BPF_ALU_NON_POINTER
, 0);
6476 static bool sanitize_needed(u8 opcode
)
6478 return opcode
== BPF_ADD
|| opcode
== BPF_SUB
;
6481 struct bpf_sanitize_info
{
6482 struct bpf_insn_aux_data aux
;
6486 static int sanitize_ptr_alu(struct bpf_verifier_env
*env
,
6487 struct bpf_insn
*insn
,
6488 const struct bpf_reg_state
*ptr_reg
,
6489 const struct bpf_reg_state
*off_reg
,
6490 struct bpf_reg_state
*dst_reg
,
6491 struct bpf_sanitize_info
*info
,
6492 const bool commit_window
)
6494 struct bpf_insn_aux_data
*aux
= commit_window
? cur_aux(env
) : &info
->aux
;
6495 struct bpf_verifier_state
*vstate
= env
->cur_state
;
6496 bool off_is_imm
= tnum_is_const(off_reg
->var_off
);
6497 bool off_is_neg
= off_reg
->smin_value
< 0;
6498 bool ptr_is_dst_reg
= ptr_reg
== dst_reg
;
6499 u8 opcode
= BPF_OP(insn
->code
);
6500 u32 alu_state
, alu_limit
;
6501 struct bpf_reg_state tmp
;
6505 if (can_skip_alu_sanitation(env
, insn
))
6508 /* We already marked aux for masking from non-speculative
6509 * paths, thus we got here in the first place. We only care
6510 * to explore bad access from here.
6512 if (vstate
->speculative
)
6515 if (!commit_window
) {
6516 if (!tnum_is_const(off_reg
->var_off
) &&
6517 (off_reg
->smin_value
< 0) != (off_reg
->smax_value
< 0))
6518 return REASON_BOUNDS
;
6520 info
->mask_to_left
= (opcode
== BPF_ADD
&& off_is_neg
) ||
6521 (opcode
== BPF_SUB
&& !off_is_neg
);
6524 err
= retrieve_ptr_limit(ptr_reg
, &alu_limit
, info
->mask_to_left
);
6528 if (commit_window
) {
6529 /* In commit phase we narrow the masking window based on
6530 * the observed pointer move after the simulated operation.
6532 alu_state
= info
->aux
.alu_state
;
6533 alu_limit
= abs(info
->aux
.alu_limit
- alu_limit
);
6535 alu_state
= off_is_neg
? BPF_ALU_NEG_VALUE
: 0;
6536 alu_state
|= off_is_imm
? BPF_ALU_IMMEDIATE
: 0;
6537 alu_state
|= ptr_is_dst_reg
?
6538 BPF_ALU_SANITIZE_SRC
: BPF_ALU_SANITIZE_DST
;
6541 err
= update_alu_sanitation_state(aux
, alu_state
, alu_limit
);
6545 /* If we're in commit phase, we're done here given we already
6546 * pushed the truncated dst_reg into the speculative verification
6549 * Also, when register is a known constant, we rewrite register-based
6550 * operation to immediate-based, and thus do not need masking (and as
6551 * a consequence, do not need to simulate the zero-truncation either).
6553 if (commit_window
|| off_is_imm
)
6556 /* Simulate and find potential out-of-bounds access under
6557 * speculative execution from truncation as a result of
6558 * masking when off was not within expected range. If off
6559 * sits in dst, then we temporarily need to move ptr there
6560 * to simulate dst (== 0) +/-= ptr. Needed, for example,
6561 * for cases where we use K-based arithmetic in one direction
6562 * and truncated reg-based in the other in order to explore
6565 if (!ptr_is_dst_reg
) {
6567 *dst_reg
= *ptr_reg
;
6569 ret
= push_stack(env
, env
->insn_idx
+ 1, env
->insn_idx
, true);
6570 if (!ptr_is_dst_reg
&& ret
)
6572 return !ret
? REASON_STACK
: 0;
6575 static void sanitize_mark_insn_seen(struct bpf_verifier_env
*env
)
6577 struct bpf_verifier_state
*vstate
= env
->cur_state
;
6579 /* If we simulate paths under speculation, we don't update the
6580 * insn as 'seen' such that when we verify unreachable paths in
6581 * the non-speculative domain, sanitize_dead_code() can still
6582 * rewrite/sanitize them.
6584 if (!vstate
->speculative
)
6585 env
->insn_aux_data
[env
->insn_idx
].seen
= env
->pass_cnt
;
6588 static int sanitize_err(struct bpf_verifier_env
*env
,
6589 const struct bpf_insn
*insn
, int reason
,
6590 const struct bpf_reg_state
*off_reg
,
6591 const struct bpf_reg_state
*dst_reg
)
6593 static const char *err
= "pointer arithmetic with it prohibited for !root";
6594 const char *op
= BPF_OP(insn
->code
) == BPF_ADD
? "add" : "sub";
6595 u32 dst
= insn
->dst_reg
, src
= insn
->src_reg
;
6599 verbose(env
, "R%d has unknown scalar with mixed signed bounds, %s\n",
6600 off_reg
== dst_reg
? dst
: src
, err
);
6603 verbose(env
, "R%d has pointer with unsupported alu operation, %s\n",
6604 off_reg
== dst_reg
? src
: dst
, err
);
6607 verbose(env
, "R%d tried to %s from different maps, paths or scalars, %s\n",
6611 verbose(env
, "R%d tried to %s beyond pointer bounds, %s\n",
6615 verbose(env
, "R%d could not be pushed for speculative verification, %s\n",
6619 verbose(env
, "verifier internal error: unknown reason (%d)\n",
6627 /* check that stack access falls within stack limits and that 'reg' doesn't
6628 * have a variable offset.
6630 * Variable offset is prohibited for unprivileged mode for simplicity since it
6631 * requires corresponding support in Spectre masking for stack ALU. See also
6632 * retrieve_ptr_limit().
6635 * 'off' includes 'reg->off'.
6637 static int check_stack_access_for_ptr_arithmetic(
6638 struct bpf_verifier_env
*env
,
6640 const struct bpf_reg_state
*reg
,
6643 if (!tnum_is_const(reg
->var_off
)) {
6646 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
6647 verbose(env
, "R%d variable stack access prohibited for !root, var_off=%s off=%d\n",
6648 regno
, tn_buf
, off
);
6652 if (off
>= 0 || off
< -MAX_BPF_STACK
) {
6653 verbose(env
, "R%d stack pointer arithmetic goes out of range, "
6654 "prohibited for !root; off=%d\n", regno
, off
);
6661 static int sanitize_check_bounds(struct bpf_verifier_env
*env
,
6662 const struct bpf_insn
*insn
,
6663 const struct bpf_reg_state
*dst_reg
)
6665 u32 dst
= insn
->dst_reg
;
6667 /* For unprivileged we require that resulting offset must be in bounds
6668 * in order to be able to sanitize access later on.
6670 if (env
->bypass_spec_v1
)
6673 switch (dst_reg
->type
) {
6675 if (check_stack_access_for_ptr_arithmetic(env
, dst
, dst_reg
,
6676 dst_reg
->off
+ dst_reg
->var_off
.value
))
6679 case PTR_TO_MAP_VALUE
:
6680 if (check_map_access(env
, dst
, dst_reg
->off
, 1, false)) {
6681 verbose(env
, "R%d pointer arithmetic of map value goes out of range, "
6682 "prohibited for !root\n", dst
);
6693 /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
6694 * Caller should also handle BPF_MOV case separately.
6695 * If we return -EACCES, caller may want to try again treating pointer as a
6696 * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks.
6698 static int adjust_ptr_min_max_vals(struct bpf_verifier_env
*env
,
6699 struct bpf_insn
*insn
,
6700 const struct bpf_reg_state
*ptr_reg
,
6701 const struct bpf_reg_state
*off_reg
)
6703 struct bpf_verifier_state
*vstate
= env
->cur_state
;
6704 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
6705 struct bpf_reg_state
*regs
= state
->regs
, *dst_reg
;
6706 bool known
= tnum_is_const(off_reg
->var_off
);
6707 s64 smin_val
= off_reg
->smin_value
, smax_val
= off_reg
->smax_value
,
6708 smin_ptr
= ptr_reg
->smin_value
, smax_ptr
= ptr_reg
->smax_value
;
6709 u64 umin_val
= off_reg
->umin_value
, umax_val
= off_reg
->umax_value
,
6710 umin_ptr
= ptr_reg
->umin_value
, umax_ptr
= ptr_reg
->umax_value
;
6711 struct bpf_sanitize_info info
= {};
6712 u8 opcode
= BPF_OP(insn
->code
);
6713 u32 dst
= insn
->dst_reg
;
6716 dst_reg
= ®s
[dst
];
6718 if ((known
&& (smin_val
!= smax_val
|| umin_val
!= umax_val
)) ||
6719 smin_val
> smax_val
|| umin_val
> umax_val
) {
6720 /* Taint dst register if offset had invalid bounds derived from
6721 * e.g. dead branches.
6723 __mark_reg_unknown(env
, dst_reg
);
6727 if (BPF_CLASS(insn
->code
) != BPF_ALU64
) {
6728 /* 32-bit ALU ops on pointers produce (meaningless) scalars */
6729 if (opcode
== BPF_SUB
&& env
->allow_ptr_leaks
) {
6730 __mark_reg_unknown(env
, dst_reg
);
6735 "R%d 32-bit pointer arithmetic prohibited\n",
6740 switch (ptr_reg
->type
) {
6741 case PTR_TO_MAP_VALUE_OR_NULL
:
6742 verbose(env
, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
6743 dst
, reg_type_str
[ptr_reg
->type
]);
6745 case CONST_PTR_TO_MAP
:
6746 /* smin_val represents the known value */
6747 if (known
&& smin_val
== 0 && opcode
== BPF_ADD
)
6750 case PTR_TO_PACKET_END
:
6752 case PTR_TO_SOCKET_OR_NULL
:
6753 case PTR_TO_SOCK_COMMON
:
6754 case PTR_TO_SOCK_COMMON_OR_NULL
:
6755 case PTR_TO_TCP_SOCK
:
6756 case PTR_TO_TCP_SOCK_OR_NULL
:
6757 case PTR_TO_XDP_SOCK
:
6758 verbose(env
, "R%d pointer arithmetic on %s prohibited\n",
6759 dst
, reg_type_str
[ptr_reg
->type
]);
6765 /* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
6766 * The id may be overwritten later if we create a new variable offset.
6768 dst_reg
->type
= ptr_reg
->type
;
6769 dst_reg
->id
= ptr_reg
->id
;
6771 if (!check_reg_sane_offset(env
, off_reg
, ptr_reg
->type
) ||
6772 !check_reg_sane_offset(env
, ptr_reg
, ptr_reg
->type
))
6775 /* pointer types do not carry 32-bit bounds at the moment. */
6776 __mark_reg32_unbounded(dst_reg
);
6778 if (sanitize_needed(opcode
)) {
6779 ret
= sanitize_ptr_alu(env
, insn
, ptr_reg
, off_reg
, dst_reg
,
6782 return sanitize_err(env
, insn
, ret
, off_reg
, dst_reg
);
6787 /* We can take a fixed offset as long as it doesn't overflow
6788 * the s32 'off' field
6790 if (known
&& (ptr_reg
->off
+ smin_val
==
6791 (s64
)(s32
)(ptr_reg
->off
+ smin_val
))) {
6792 /* pointer += K. Accumulate it into fixed offset */
6793 dst_reg
->smin_value
= smin_ptr
;
6794 dst_reg
->smax_value
= smax_ptr
;
6795 dst_reg
->umin_value
= umin_ptr
;
6796 dst_reg
->umax_value
= umax_ptr
;
6797 dst_reg
->var_off
= ptr_reg
->var_off
;
6798 dst_reg
->off
= ptr_reg
->off
+ smin_val
;
6799 dst_reg
->raw
= ptr_reg
->raw
;
6802 /* A new variable offset is created. Note that off_reg->off
6803 * == 0, since it's a scalar.
6804 * dst_reg gets the pointer type and since some positive
6805 * integer value was added to the pointer, give it a new 'id'
6806 * if it's a PTR_TO_PACKET.
6807 * this creates a new 'base' pointer, off_reg (variable) gets
6808 * added into the variable offset, and we copy the fixed offset
6811 if (signed_add_overflows(smin_ptr
, smin_val
) ||
6812 signed_add_overflows(smax_ptr
, smax_val
)) {
6813 dst_reg
->smin_value
= S64_MIN
;
6814 dst_reg
->smax_value
= S64_MAX
;
6816 dst_reg
->smin_value
= smin_ptr
+ smin_val
;
6817 dst_reg
->smax_value
= smax_ptr
+ smax_val
;
6819 if (umin_ptr
+ umin_val
< umin_ptr
||
6820 umax_ptr
+ umax_val
< umax_ptr
) {
6821 dst_reg
->umin_value
= 0;
6822 dst_reg
->umax_value
= U64_MAX
;
6824 dst_reg
->umin_value
= umin_ptr
+ umin_val
;
6825 dst_reg
->umax_value
= umax_ptr
+ umax_val
;
6827 dst_reg
->var_off
= tnum_add(ptr_reg
->var_off
, off_reg
->var_off
);
6828 dst_reg
->off
= ptr_reg
->off
;
6829 dst_reg
->raw
= ptr_reg
->raw
;
6830 if (reg_is_pkt_pointer(ptr_reg
)) {
6831 dst_reg
->id
= ++env
->id_gen
;
6832 /* something was added to pkt_ptr, set range to zero */
6833 memset(&dst_reg
->raw
, 0, sizeof(dst_reg
->raw
));
6837 if (dst_reg
== off_reg
) {
6838 /* scalar -= pointer. Creates an unknown scalar */
6839 verbose(env
, "R%d tried to subtract pointer from scalar\n",
6843 /* We don't allow subtraction from FP, because (according to
6844 * test_verifier.c test "invalid fp arithmetic", JITs might not
6845 * be able to deal with it.
6847 if (ptr_reg
->type
== PTR_TO_STACK
) {
6848 verbose(env
, "R%d subtraction from stack pointer prohibited\n",
6852 if (known
&& (ptr_reg
->off
- smin_val
==
6853 (s64
)(s32
)(ptr_reg
->off
- smin_val
))) {
6854 /* pointer -= K. Subtract it from fixed offset */
6855 dst_reg
->smin_value
= smin_ptr
;
6856 dst_reg
->smax_value
= smax_ptr
;
6857 dst_reg
->umin_value
= umin_ptr
;
6858 dst_reg
->umax_value
= umax_ptr
;
6859 dst_reg
->var_off
= ptr_reg
->var_off
;
6860 dst_reg
->id
= ptr_reg
->id
;
6861 dst_reg
->off
= ptr_reg
->off
- smin_val
;
6862 dst_reg
->raw
= ptr_reg
->raw
;
6865 /* A new variable offset is created. If the subtrahend is known
6866 * nonnegative, then any reg->range we had before is still good.
6868 if (signed_sub_overflows(smin_ptr
, smax_val
) ||
6869 signed_sub_overflows(smax_ptr
, smin_val
)) {
6870 /* Overflow possible, we know nothing */
6871 dst_reg
->smin_value
= S64_MIN
;
6872 dst_reg
->smax_value
= S64_MAX
;
6874 dst_reg
->smin_value
= smin_ptr
- smax_val
;
6875 dst_reg
->smax_value
= smax_ptr
- smin_val
;
6877 if (umin_ptr
< umax_val
) {
6878 /* Overflow possible, we know nothing */
6879 dst_reg
->umin_value
= 0;
6880 dst_reg
->umax_value
= U64_MAX
;
6882 /* Cannot overflow (as long as bounds are consistent) */
6883 dst_reg
->umin_value
= umin_ptr
- umax_val
;
6884 dst_reg
->umax_value
= umax_ptr
- umin_val
;
6886 dst_reg
->var_off
= tnum_sub(ptr_reg
->var_off
, off_reg
->var_off
);
6887 dst_reg
->off
= ptr_reg
->off
;
6888 dst_reg
->raw
= ptr_reg
->raw
;
6889 if (reg_is_pkt_pointer(ptr_reg
)) {
6890 dst_reg
->id
= ++env
->id_gen
;
6891 /* something was added to pkt_ptr, set range to zero */
6893 memset(&dst_reg
->raw
, 0, sizeof(dst_reg
->raw
));
6899 /* bitwise ops on pointers are troublesome, prohibit. */
6900 verbose(env
, "R%d bitwise operator %s on pointer prohibited\n",
6901 dst
, bpf_alu_string
[opcode
>> 4]);
6904 /* other operators (e.g. MUL,LSH) produce non-pointer results */
6905 verbose(env
, "R%d pointer arithmetic with %s operator prohibited\n",
6906 dst
, bpf_alu_string
[opcode
>> 4]);
6910 if (!check_reg_sane_offset(env
, dst_reg
, ptr_reg
->type
))
6913 __update_reg_bounds(dst_reg
);
6914 __reg_deduce_bounds(dst_reg
);
6915 __reg_bound_offset(dst_reg
);
6917 if (sanitize_check_bounds(env
, insn
, dst_reg
) < 0)
6919 if (sanitize_needed(opcode
)) {
6920 ret
= sanitize_ptr_alu(env
, insn
, dst_reg
, off_reg
, dst_reg
,
6923 return sanitize_err(env
, insn
, ret
, off_reg
, dst_reg
);
6929 static void scalar32_min_max_add(struct bpf_reg_state
*dst_reg
,
6930 struct bpf_reg_state
*src_reg
)
6932 s32 smin_val
= src_reg
->s32_min_value
;
6933 s32 smax_val
= src_reg
->s32_max_value
;
6934 u32 umin_val
= src_reg
->u32_min_value
;
6935 u32 umax_val
= src_reg
->u32_max_value
;
6937 if (signed_add32_overflows(dst_reg
->s32_min_value
, smin_val
) ||
6938 signed_add32_overflows(dst_reg
->s32_max_value
, smax_val
)) {
6939 dst_reg
->s32_min_value
= S32_MIN
;
6940 dst_reg
->s32_max_value
= S32_MAX
;
6942 dst_reg
->s32_min_value
+= smin_val
;
6943 dst_reg
->s32_max_value
+= smax_val
;
6945 if (dst_reg
->u32_min_value
+ umin_val
< umin_val
||
6946 dst_reg
->u32_max_value
+ umax_val
< umax_val
) {
6947 dst_reg
->u32_min_value
= 0;
6948 dst_reg
->u32_max_value
= U32_MAX
;
6950 dst_reg
->u32_min_value
+= umin_val
;
6951 dst_reg
->u32_max_value
+= umax_val
;
6955 static void scalar_min_max_add(struct bpf_reg_state
*dst_reg
,
6956 struct bpf_reg_state
*src_reg
)
6958 s64 smin_val
= src_reg
->smin_value
;
6959 s64 smax_val
= src_reg
->smax_value
;
6960 u64 umin_val
= src_reg
->umin_value
;
6961 u64 umax_val
= src_reg
->umax_value
;
6963 if (signed_add_overflows(dst_reg
->smin_value
, smin_val
) ||
6964 signed_add_overflows(dst_reg
->smax_value
, smax_val
)) {
6965 dst_reg
->smin_value
= S64_MIN
;
6966 dst_reg
->smax_value
= S64_MAX
;
6968 dst_reg
->smin_value
+= smin_val
;
6969 dst_reg
->smax_value
+= smax_val
;
6971 if (dst_reg
->umin_value
+ umin_val
< umin_val
||
6972 dst_reg
->umax_value
+ umax_val
< umax_val
) {
6973 dst_reg
->umin_value
= 0;
6974 dst_reg
->umax_value
= U64_MAX
;
6976 dst_reg
->umin_value
+= umin_val
;
6977 dst_reg
->umax_value
+= umax_val
;
6981 static void scalar32_min_max_sub(struct bpf_reg_state
*dst_reg
,
6982 struct bpf_reg_state
*src_reg
)
6984 s32 smin_val
= src_reg
->s32_min_value
;
6985 s32 smax_val
= src_reg
->s32_max_value
;
6986 u32 umin_val
= src_reg
->u32_min_value
;
6987 u32 umax_val
= src_reg
->u32_max_value
;
6989 if (signed_sub32_overflows(dst_reg
->s32_min_value
, smax_val
) ||
6990 signed_sub32_overflows(dst_reg
->s32_max_value
, smin_val
)) {
6991 /* Overflow possible, we know nothing */
6992 dst_reg
->s32_min_value
= S32_MIN
;
6993 dst_reg
->s32_max_value
= S32_MAX
;
6995 dst_reg
->s32_min_value
-= smax_val
;
6996 dst_reg
->s32_max_value
-= smin_val
;
6998 if (dst_reg
->u32_min_value
< umax_val
) {
6999 /* Overflow possible, we know nothing */
7000 dst_reg
->u32_min_value
= 0;
7001 dst_reg
->u32_max_value
= U32_MAX
;
7003 /* Cannot overflow (as long as bounds are consistent) */
7004 dst_reg
->u32_min_value
-= umax_val
;
7005 dst_reg
->u32_max_value
-= umin_val
;
7009 static void scalar_min_max_sub(struct bpf_reg_state
*dst_reg
,
7010 struct bpf_reg_state
*src_reg
)
7012 s64 smin_val
= src_reg
->smin_value
;
7013 s64 smax_val
= src_reg
->smax_value
;
7014 u64 umin_val
= src_reg
->umin_value
;
7015 u64 umax_val
= src_reg
->umax_value
;
7017 if (signed_sub_overflows(dst_reg
->smin_value
, smax_val
) ||
7018 signed_sub_overflows(dst_reg
->smax_value
, smin_val
)) {
7019 /* Overflow possible, we know nothing */
7020 dst_reg
->smin_value
= S64_MIN
;
7021 dst_reg
->smax_value
= S64_MAX
;
7023 dst_reg
->smin_value
-= smax_val
;
7024 dst_reg
->smax_value
-= smin_val
;
7026 if (dst_reg
->umin_value
< umax_val
) {
7027 /* Overflow possible, we know nothing */
7028 dst_reg
->umin_value
= 0;
7029 dst_reg
->umax_value
= U64_MAX
;
7031 /* Cannot overflow (as long as bounds are consistent) */
7032 dst_reg
->umin_value
-= umax_val
;
7033 dst_reg
->umax_value
-= umin_val
;
7037 static void scalar32_min_max_mul(struct bpf_reg_state
*dst_reg
,
7038 struct bpf_reg_state
*src_reg
)
7040 s32 smin_val
= src_reg
->s32_min_value
;
7041 u32 umin_val
= src_reg
->u32_min_value
;
7042 u32 umax_val
= src_reg
->u32_max_value
;
7044 if (smin_val
< 0 || dst_reg
->s32_min_value
< 0) {
7045 /* Ain't nobody got time to multiply that sign */
7046 __mark_reg32_unbounded(dst_reg
);
7049 /* Both values are positive, so we can work with unsigned and
7050 * copy the result to signed (unless it exceeds S32_MAX).
7052 if (umax_val
> U16_MAX
|| dst_reg
->u32_max_value
> U16_MAX
) {
7053 /* Potential overflow, we know nothing */
7054 __mark_reg32_unbounded(dst_reg
);
7057 dst_reg
->u32_min_value
*= umin_val
;
7058 dst_reg
->u32_max_value
*= umax_val
;
7059 if (dst_reg
->u32_max_value
> S32_MAX
) {
7060 /* Overflow possible, we know nothing */
7061 dst_reg
->s32_min_value
= S32_MIN
;
7062 dst_reg
->s32_max_value
= S32_MAX
;
7064 dst_reg
->s32_min_value
= dst_reg
->u32_min_value
;
7065 dst_reg
->s32_max_value
= dst_reg
->u32_max_value
;
7069 static void scalar_min_max_mul(struct bpf_reg_state
*dst_reg
,
7070 struct bpf_reg_state
*src_reg
)
7072 s64 smin_val
= src_reg
->smin_value
;
7073 u64 umin_val
= src_reg
->umin_value
;
7074 u64 umax_val
= src_reg
->umax_value
;
7076 if (smin_val
< 0 || dst_reg
->smin_value
< 0) {
7077 /* Ain't nobody got time to multiply that sign */
7078 __mark_reg64_unbounded(dst_reg
);
7081 /* Both values are positive, so we can work with unsigned and
7082 * copy the result to signed (unless it exceeds S64_MAX).
7084 if (umax_val
> U32_MAX
|| dst_reg
->umax_value
> U32_MAX
) {
7085 /* Potential overflow, we know nothing */
7086 __mark_reg64_unbounded(dst_reg
);
7089 dst_reg
->umin_value
*= umin_val
;
7090 dst_reg
->umax_value
*= umax_val
;
7091 if (dst_reg
->umax_value
> S64_MAX
) {
7092 /* Overflow possible, we know nothing */
7093 dst_reg
->smin_value
= S64_MIN
;
7094 dst_reg
->smax_value
= S64_MAX
;
7096 dst_reg
->smin_value
= dst_reg
->umin_value
;
7097 dst_reg
->smax_value
= dst_reg
->umax_value
;
7101 static void scalar32_min_max_and(struct bpf_reg_state
*dst_reg
,
7102 struct bpf_reg_state
*src_reg
)
7104 bool src_known
= tnum_subreg_is_const(src_reg
->var_off
);
7105 bool dst_known
= tnum_subreg_is_const(dst_reg
->var_off
);
7106 struct tnum var32_off
= tnum_subreg(dst_reg
->var_off
);
7107 s32 smin_val
= src_reg
->s32_min_value
;
7108 u32 umax_val
= src_reg
->u32_max_value
;
7110 if (src_known
&& dst_known
) {
7111 __mark_reg32_known(dst_reg
, var32_off
.value
);
7115 /* We get our minimum from the var_off, since that's inherently
7116 * bitwise. Our maximum is the minimum of the operands' maxima.
7118 dst_reg
->u32_min_value
= var32_off
.value
;
7119 dst_reg
->u32_max_value
= min(dst_reg
->u32_max_value
, umax_val
);
7120 if (dst_reg
->s32_min_value
< 0 || smin_val
< 0) {
7121 /* Lose signed bounds when ANDing negative numbers,
7122 * ain't nobody got time for that.
7124 dst_reg
->s32_min_value
= S32_MIN
;
7125 dst_reg
->s32_max_value
= S32_MAX
;
7127 /* ANDing two positives gives a positive, so safe to
7128 * cast result into s64.
7130 dst_reg
->s32_min_value
= dst_reg
->u32_min_value
;
7131 dst_reg
->s32_max_value
= dst_reg
->u32_max_value
;
7135 static void scalar_min_max_and(struct bpf_reg_state
*dst_reg
,
7136 struct bpf_reg_state
*src_reg
)
7138 bool src_known
= tnum_is_const(src_reg
->var_off
);
7139 bool dst_known
= tnum_is_const(dst_reg
->var_off
);
7140 s64 smin_val
= src_reg
->smin_value
;
7141 u64 umax_val
= src_reg
->umax_value
;
7143 if (src_known
&& dst_known
) {
7144 __mark_reg_known(dst_reg
, dst_reg
->var_off
.value
);
7148 /* We get our minimum from the var_off, since that's inherently
7149 * bitwise. Our maximum is the minimum of the operands' maxima.
7151 dst_reg
->umin_value
= dst_reg
->var_off
.value
;
7152 dst_reg
->umax_value
= min(dst_reg
->umax_value
, umax_val
);
7153 if (dst_reg
->smin_value
< 0 || smin_val
< 0) {
7154 /* Lose signed bounds when ANDing negative numbers,
7155 * ain't nobody got time for that.
7157 dst_reg
->smin_value
= S64_MIN
;
7158 dst_reg
->smax_value
= S64_MAX
;
7160 /* ANDing two positives gives a positive, so safe to
7161 * cast result into s64.
7163 dst_reg
->smin_value
= dst_reg
->umin_value
;
7164 dst_reg
->smax_value
= dst_reg
->umax_value
;
7166 /* We may learn something more from the var_off */
7167 __update_reg_bounds(dst_reg
);
7170 static void scalar32_min_max_or(struct bpf_reg_state
*dst_reg
,
7171 struct bpf_reg_state
*src_reg
)
7173 bool src_known
= tnum_subreg_is_const(src_reg
->var_off
);
7174 bool dst_known
= tnum_subreg_is_const(dst_reg
->var_off
);
7175 struct tnum var32_off
= tnum_subreg(dst_reg
->var_off
);
7176 s32 smin_val
= src_reg
->s32_min_value
;
7177 u32 umin_val
= src_reg
->u32_min_value
;
7179 if (src_known
&& dst_known
) {
7180 __mark_reg32_known(dst_reg
, var32_off
.value
);
7184 /* We get our maximum from the var_off, and our minimum is the
7185 * maximum of the operands' minima
7187 dst_reg
->u32_min_value
= max(dst_reg
->u32_min_value
, umin_val
);
7188 dst_reg
->u32_max_value
= var32_off
.value
| var32_off
.mask
;
7189 if (dst_reg
->s32_min_value
< 0 || smin_val
< 0) {
7190 /* Lose signed bounds when ORing negative numbers,
7191 * ain't nobody got time for that.
7193 dst_reg
->s32_min_value
= S32_MIN
;
7194 dst_reg
->s32_max_value
= S32_MAX
;
7196 /* ORing two positives gives a positive, so safe to
7197 * cast result into s64.
7199 dst_reg
->s32_min_value
= dst_reg
->u32_min_value
;
7200 dst_reg
->s32_max_value
= dst_reg
->u32_max_value
;
7204 static void scalar_min_max_or(struct bpf_reg_state
*dst_reg
,
7205 struct bpf_reg_state
*src_reg
)
7207 bool src_known
= tnum_is_const(src_reg
->var_off
);
7208 bool dst_known
= tnum_is_const(dst_reg
->var_off
);
7209 s64 smin_val
= src_reg
->smin_value
;
7210 u64 umin_val
= src_reg
->umin_value
;
7212 if (src_known
&& dst_known
) {
7213 __mark_reg_known(dst_reg
, dst_reg
->var_off
.value
);
7217 /* We get our maximum from the var_off, and our minimum is the
7218 * maximum of the operands' minima
7220 dst_reg
->umin_value
= max(dst_reg
->umin_value
, umin_val
);
7221 dst_reg
->umax_value
= dst_reg
->var_off
.value
| dst_reg
->var_off
.mask
;
7222 if (dst_reg
->smin_value
< 0 || smin_val
< 0) {
7223 /* Lose signed bounds when ORing negative numbers,
7224 * ain't nobody got time for that.
7226 dst_reg
->smin_value
= S64_MIN
;
7227 dst_reg
->smax_value
= S64_MAX
;
7229 /* ORing two positives gives a positive, so safe to
7230 * cast result into s64.
7232 dst_reg
->smin_value
= dst_reg
->umin_value
;
7233 dst_reg
->smax_value
= dst_reg
->umax_value
;
7235 /* We may learn something more from the var_off */
7236 __update_reg_bounds(dst_reg
);
7239 static void scalar32_min_max_xor(struct bpf_reg_state
*dst_reg
,
7240 struct bpf_reg_state
*src_reg
)
7242 bool src_known
= tnum_subreg_is_const(src_reg
->var_off
);
7243 bool dst_known
= tnum_subreg_is_const(dst_reg
->var_off
);
7244 struct tnum var32_off
= tnum_subreg(dst_reg
->var_off
);
7245 s32 smin_val
= src_reg
->s32_min_value
;
7247 if (src_known
&& dst_known
) {
7248 __mark_reg32_known(dst_reg
, var32_off
.value
);
7252 /* We get both minimum and maximum from the var32_off. */
7253 dst_reg
->u32_min_value
= var32_off
.value
;
7254 dst_reg
->u32_max_value
= var32_off
.value
| var32_off
.mask
;
7256 if (dst_reg
->s32_min_value
>= 0 && smin_val
>= 0) {
7257 /* XORing two positive sign numbers gives a positive,
7258 * so safe to cast u32 result into s32.
7260 dst_reg
->s32_min_value
= dst_reg
->u32_min_value
;
7261 dst_reg
->s32_max_value
= dst_reg
->u32_max_value
;
7263 dst_reg
->s32_min_value
= S32_MIN
;
7264 dst_reg
->s32_max_value
= S32_MAX
;
7268 static void scalar_min_max_xor(struct bpf_reg_state
*dst_reg
,
7269 struct bpf_reg_state
*src_reg
)
7271 bool src_known
= tnum_is_const(src_reg
->var_off
);
7272 bool dst_known
= tnum_is_const(dst_reg
->var_off
);
7273 s64 smin_val
= src_reg
->smin_value
;
7275 if (src_known
&& dst_known
) {
7276 /* dst_reg->var_off.value has been updated earlier */
7277 __mark_reg_known(dst_reg
, dst_reg
->var_off
.value
);
7281 /* We get both minimum and maximum from the var_off. */
7282 dst_reg
->umin_value
= dst_reg
->var_off
.value
;
7283 dst_reg
->umax_value
= dst_reg
->var_off
.value
| dst_reg
->var_off
.mask
;
7285 if (dst_reg
->smin_value
>= 0 && smin_val
>= 0) {
7286 /* XORing two positive sign numbers gives a positive,
7287 * so safe to cast u64 result into s64.
7289 dst_reg
->smin_value
= dst_reg
->umin_value
;
7290 dst_reg
->smax_value
= dst_reg
->umax_value
;
7292 dst_reg
->smin_value
= S64_MIN
;
7293 dst_reg
->smax_value
= S64_MAX
;
7296 __update_reg_bounds(dst_reg
);
7299 static void __scalar32_min_max_lsh(struct bpf_reg_state
*dst_reg
,
7300 u64 umin_val
, u64 umax_val
)
7302 /* We lose all sign bit information (except what we can pick
7305 dst_reg
->s32_min_value
= S32_MIN
;
7306 dst_reg
->s32_max_value
= S32_MAX
;
7307 /* If we might shift our top bit out, then we know nothing */
7308 if (umax_val
> 31 || dst_reg
->u32_max_value
> 1ULL << (31 - umax_val
)) {
7309 dst_reg
->u32_min_value
= 0;
7310 dst_reg
->u32_max_value
= U32_MAX
;
7312 dst_reg
->u32_min_value
<<= umin_val
;
7313 dst_reg
->u32_max_value
<<= umax_val
;
7317 static void scalar32_min_max_lsh(struct bpf_reg_state
*dst_reg
,
7318 struct bpf_reg_state
*src_reg
)
7320 u32 umax_val
= src_reg
->u32_max_value
;
7321 u32 umin_val
= src_reg
->u32_min_value
;
7322 /* u32 alu operation will zext upper bits */
7323 struct tnum subreg
= tnum_subreg(dst_reg
->var_off
);
7325 __scalar32_min_max_lsh(dst_reg
, umin_val
, umax_val
);
7326 dst_reg
->var_off
= tnum_subreg(tnum_lshift(subreg
, umin_val
));
7327 /* Not required but being careful mark reg64 bounds as unknown so
7328 * that we are forced to pick them up from tnum and zext later and
7329 * if some path skips this step we are still safe.
7331 __mark_reg64_unbounded(dst_reg
);
7332 __update_reg32_bounds(dst_reg
);
7335 static void __scalar64_min_max_lsh(struct bpf_reg_state
*dst_reg
,
7336 u64 umin_val
, u64 umax_val
)
7338 /* Special case <<32 because it is a common compiler pattern to sign
7339 * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are
7340 * positive we know this shift will also be positive so we can track
7341 * bounds correctly. Otherwise we lose all sign bit information except
7342 * what we can pick up from var_off. Perhaps we can generalize this
7343 * later to shifts of any length.
7345 if (umin_val
== 32 && umax_val
== 32 && dst_reg
->s32_max_value
>= 0)
7346 dst_reg
->smax_value
= (s64
)dst_reg
->s32_max_value
<< 32;
7348 dst_reg
->smax_value
= S64_MAX
;
7350 if (umin_val
== 32 && umax_val
== 32 && dst_reg
->s32_min_value
>= 0)
7351 dst_reg
->smin_value
= (s64
)dst_reg
->s32_min_value
<< 32;
7353 dst_reg
->smin_value
= S64_MIN
;
7355 /* If we might shift our top bit out, then we know nothing */
7356 if (dst_reg
->umax_value
> 1ULL << (63 - umax_val
)) {
7357 dst_reg
->umin_value
= 0;
7358 dst_reg
->umax_value
= U64_MAX
;
7360 dst_reg
->umin_value
<<= umin_val
;
7361 dst_reg
->umax_value
<<= umax_val
;
7365 static void scalar_min_max_lsh(struct bpf_reg_state
*dst_reg
,
7366 struct bpf_reg_state
*src_reg
)
7368 u64 umax_val
= src_reg
->umax_value
;
7369 u64 umin_val
= src_reg
->umin_value
;
7371 /* scalar64 calc uses 32bit unshifted bounds so must be called first */
7372 __scalar64_min_max_lsh(dst_reg
, umin_val
, umax_val
);
7373 __scalar32_min_max_lsh(dst_reg
, umin_val
, umax_val
);
7375 dst_reg
->var_off
= tnum_lshift(dst_reg
->var_off
, umin_val
);
7376 /* We may learn something more from the var_off */
7377 __update_reg_bounds(dst_reg
);
7380 static void scalar32_min_max_rsh(struct bpf_reg_state
*dst_reg
,
7381 struct bpf_reg_state
*src_reg
)
7383 struct tnum subreg
= tnum_subreg(dst_reg
->var_off
);
7384 u32 umax_val
= src_reg
->u32_max_value
;
7385 u32 umin_val
= src_reg
->u32_min_value
;
7387 /* BPF_RSH is an unsigned shift. If the value in dst_reg might
7388 * be negative, then either:
7389 * 1) src_reg might be zero, so the sign bit of the result is
7390 * unknown, so we lose our signed bounds
7391 * 2) it's known negative, thus the unsigned bounds capture the
7393 * 3) the signed bounds cross zero, so they tell us nothing
7395 * If the value in dst_reg is known nonnegative, then again the
7396 * unsigned bounds capture the signed bounds.
7397 * Thus, in all cases it suffices to blow away our signed bounds
7398 * and rely on inferring new ones from the unsigned bounds and
7399 * var_off of the result.
7401 dst_reg
->s32_min_value
= S32_MIN
;
7402 dst_reg
->s32_max_value
= S32_MAX
;
7404 dst_reg
->var_off
= tnum_rshift(subreg
, umin_val
);
7405 dst_reg
->u32_min_value
>>= umax_val
;
7406 dst_reg
->u32_max_value
>>= umin_val
;
7408 __mark_reg64_unbounded(dst_reg
);
7409 __update_reg32_bounds(dst_reg
);
7412 static void scalar_min_max_rsh(struct bpf_reg_state
*dst_reg
,
7413 struct bpf_reg_state
*src_reg
)
7415 u64 umax_val
= src_reg
->umax_value
;
7416 u64 umin_val
= src_reg
->umin_value
;
7418 /* BPF_RSH is an unsigned shift. If the value in dst_reg might
7419 * be negative, then either:
7420 * 1) src_reg might be zero, so the sign bit of the result is
7421 * unknown, so we lose our signed bounds
7422 * 2) it's known negative, thus the unsigned bounds capture the
7424 * 3) the signed bounds cross zero, so they tell us nothing
7426 * If the value in dst_reg is known nonnegative, then again the
7427 * unsigned bounds capture the signed bounds.
7428 * Thus, in all cases it suffices to blow away our signed bounds
7429 * and rely on inferring new ones from the unsigned bounds and
7430 * var_off of the result.
7432 dst_reg
->smin_value
= S64_MIN
;
7433 dst_reg
->smax_value
= S64_MAX
;
7434 dst_reg
->var_off
= tnum_rshift(dst_reg
->var_off
, umin_val
);
7435 dst_reg
->umin_value
>>= umax_val
;
7436 dst_reg
->umax_value
>>= umin_val
;
7438 /* Its not easy to operate on alu32 bounds here because it depends
7439 * on bits being shifted in. Take easy way out and mark unbounded
7440 * so we can recalculate later from tnum.
7442 __mark_reg32_unbounded(dst_reg
);
7443 __update_reg_bounds(dst_reg
);
7446 static void scalar32_min_max_arsh(struct bpf_reg_state
*dst_reg
,
7447 struct bpf_reg_state
*src_reg
)
7449 u64 umin_val
= src_reg
->u32_min_value
;
7451 /* Upon reaching here, src_known is true and
7452 * umax_val is equal to umin_val.
7454 dst_reg
->s32_min_value
= (u32
)(((s32
)dst_reg
->s32_min_value
) >> umin_val
);
7455 dst_reg
->s32_max_value
= (u32
)(((s32
)dst_reg
->s32_max_value
) >> umin_val
);
7457 dst_reg
->var_off
= tnum_arshift(tnum_subreg(dst_reg
->var_off
), umin_val
, 32);
7459 /* blow away the dst_reg umin_value/umax_value and rely on
7460 * dst_reg var_off to refine the result.
7462 dst_reg
->u32_min_value
= 0;
7463 dst_reg
->u32_max_value
= U32_MAX
;
7465 __mark_reg64_unbounded(dst_reg
);
7466 __update_reg32_bounds(dst_reg
);
7469 static void scalar_min_max_arsh(struct bpf_reg_state
*dst_reg
,
7470 struct bpf_reg_state
*src_reg
)
7472 u64 umin_val
= src_reg
->umin_value
;
7474 /* Upon reaching here, src_known is true and umax_val is equal
7477 dst_reg
->smin_value
>>= umin_val
;
7478 dst_reg
->smax_value
>>= umin_val
;
7480 dst_reg
->var_off
= tnum_arshift(dst_reg
->var_off
, umin_val
, 64);
7482 /* blow away the dst_reg umin_value/umax_value and rely on
7483 * dst_reg var_off to refine the result.
7485 dst_reg
->umin_value
= 0;
7486 dst_reg
->umax_value
= U64_MAX
;
7488 /* Its not easy to operate on alu32 bounds here because it depends
7489 * on bits being shifted in from upper 32-bits. Take easy way out
7490 * and mark unbounded so we can recalculate later from tnum.
7492 __mark_reg32_unbounded(dst_reg
);
7493 __update_reg_bounds(dst_reg
);
7496 /* WARNING: This function does calculations on 64-bit values, but the actual
7497 * execution may occur on 32-bit values. Therefore, things like bitshifts
7498 * need extra checks in the 32-bit case.
7500 static int adjust_scalar_min_max_vals(struct bpf_verifier_env
*env
,
7501 struct bpf_insn
*insn
,
7502 struct bpf_reg_state
*dst_reg
,
7503 struct bpf_reg_state src_reg
)
7505 struct bpf_reg_state
*regs
= cur_regs(env
);
7506 u8 opcode
= BPF_OP(insn
->code
);
7508 s64 smin_val
, smax_val
;
7509 u64 umin_val
, umax_val
;
7510 s32 s32_min_val
, s32_max_val
;
7511 u32 u32_min_val
, u32_max_val
;
7512 u64 insn_bitness
= (BPF_CLASS(insn
->code
) == BPF_ALU64
) ? 64 : 32;
7513 bool alu32
= (BPF_CLASS(insn
->code
) != BPF_ALU64
);
7516 smin_val
= src_reg
.smin_value
;
7517 smax_val
= src_reg
.smax_value
;
7518 umin_val
= src_reg
.umin_value
;
7519 umax_val
= src_reg
.umax_value
;
7521 s32_min_val
= src_reg
.s32_min_value
;
7522 s32_max_val
= src_reg
.s32_max_value
;
7523 u32_min_val
= src_reg
.u32_min_value
;
7524 u32_max_val
= src_reg
.u32_max_value
;
7527 src_known
= tnum_subreg_is_const(src_reg
.var_off
);
7529 (s32_min_val
!= s32_max_val
|| u32_min_val
!= u32_max_val
)) ||
7530 s32_min_val
> s32_max_val
|| u32_min_val
> u32_max_val
) {
7531 /* Taint dst register if offset had invalid bounds
7532 * derived from e.g. dead branches.
7534 __mark_reg_unknown(env
, dst_reg
);
7538 src_known
= tnum_is_const(src_reg
.var_off
);
7540 (smin_val
!= smax_val
|| umin_val
!= umax_val
)) ||
7541 smin_val
> smax_val
|| umin_val
> umax_val
) {
7542 /* Taint dst register if offset had invalid bounds
7543 * derived from e.g. dead branches.
7545 __mark_reg_unknown(env
, dst_reg
);
7551 opcode
!= BPF_ADD
&& opcode
!= BPF_SUB
&& opcode
!= BPF_AND
) {
7552 __mark_reg_unknown(env
, dst_reg
);
7556 if (sanitize_needed(opcode
)) {
7557 ret
= sanitize_val_alu(env
, insn
);
7559 return sanitize_err(env
, insn
, ret
, NULL
, NULL
);
7562 /* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops.
7563 * There are two classes of instructions: The first class we track both
7564 * alu32 and alu64 sign/unsigned bounds independently this provides the
7565 * greatest amount of precision when alu operations are mixed with jmp32
7566 * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD,
7567 * and BPF_OR. This is possible because these ops have fairly easy to
7568 * understand and calculate behavior in both 32-bit and 64-bit alu ops.
7569 * See alu32 verifier tests for examples. The second class of
7570 * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy
7571 * with regards to tracking sign/unsigned bounds because the bits may
7572 * cross subreg boundaries in the alu64 case. When this happens we mark
7573 * the reg unbounded in the subreg bound space and use the resulting
7574 * tnum to calculate an approximation of the sign/unsigned bounds.
7578 scalar32_min_max_add(dst_reg
, &src_reg
);
7579 scalar_min_max_add(dst_reg
, &src_reg
);
7580 dst_reg
->var_off
= tnum_add(dst_reg
->var_off
, src_reg
.var_off
);
7583 scalar32_min_max_sub(dst_reg
, &src_reg
);
7584 scalar_min_max_sub(dst_reg
, &src_reg
);
7585 dst_reg
->var_off
= tnum_sub(dst_reg
->var_off
, src_reg
.var_off
);
7588 dst_reg
->var_off
= tnum_mul(dst_reg
->var_off
, src_reg
.var_off
);
7589 scalar32_min_max_mul(dst_reg
, &src_reg
);
7590 scalar_min_max_mul(dst_reg
, &src_reg
);
7593 dst_reg
->var_off
= tnum_and(dst_reg
->var_off
, src_reg
.var_off
);
7594 scalar32_min_max_and(dst_reg
, &src_reg
);
7595 scalar_min_max_and(dst_reg
, &src_reg
);
7598 dst_reg
->var_off
= tnum_or(dst_reg
->var_off
, src_reg
.var_off
);
7599 scalar32_min_max_or(dst_reg
, &src_reg
);
7600 scalar_min_max_or(dst_reg
, &src_reg
);
7603 dst_reg
->var_off
= tnum_xor(dst_reg
->var_off
, src_reg
.var_off
);
7604 scalar32_min_max_xor(dst_reg
, &src_reg
);
7605 scalar_min_max_xor(dst_reg
, &src_reg
);
7608 if (umax_val
>= insn_bitness
) {
7609 /* Shifts greater than 31 or 63 are undefined.
7610 * This includes shifts by a negative number.
7612 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
7616 scalar32_min_max_lsh(dst_reg
, &src_reg
);
7618 scalar_min_max_lsh(dst_reg
, &src_reg
);
7621 if (umax_val
>= insn_bitness
) {
7622 /* Shifts greater than 31 or 63 are undefined.
7623 * This includes shifts by a negative number.
7625 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
7629 scalar32_min_max_rsh(dst_reg
, &src_reg
);
7631 scalar_min_max_rsh(dst_reg
, &src_reg
);
7634 if (umax_val
>= insn_bitness
) {
7635 /* Shifts greater than 31 or 63 are undefined.
7636 * This includes shifts by a negative number.
7638 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
7642 scalar32_min_max_arsh(dst_reg
, &src_reg
);
7644 scalar_min_max_arsh(dst_reg
, &src_reg
);
7647 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
7651 /* ALU32 ops are zero extended into 64bit register */
7653 zext_32_to_64(dst_reg
);
7655 __update_reg_bounds(dst_reg
);
7656 __reg_deduce_bounds(dst_reg
);
7657 __reg_bound_offset(dst_reg
);
7661 /* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max
7664 static int adjust_reg_min_max_vals(struct bpf_verifier_env
*env
,
7665 struct bpf_insn
*insn
)
7667 struct bpf_verifier_state
*vstate
= env
->cur_state
;
7668 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
7669 struct bpf_reg_state
*regs
= state
->regs
, *dst_reg
, *src_reg
;
7670 struct bpf_reg_state
*ptr_reg
= NULL
, off_reg
= {0};
7671 u8 opcode
= BPF_OP(insn
->code
);
7674 dst_reg
= ®s
[insn
->dst_reg
];
7676 if (dst_reg
->type
!= SCALAR_VALUE
)
7679 /* Make sure ID is cleared otherwise dst_reg min/max could be
7680 * incorrectly propagated into other registers by find_equal_scalars()
7683 if (BPF_SRC(insn
->code
) == BPF_X
) {
7684 src_reg
= ®s
[insn
->src_reg
];
7685 if (src_reg
->type
!= SCALAR_VALUE
) {
7686 if (dst_reg
->type
!= SCALAR_VALUE
) {
7687 /* Combining two pointers by any ALU op yields
7688 * an arbitrary scalar. Disallow all math except
7689 * pointer subtraction
7691 if (opcode
== BPF_SUB
&& env
->allow_ptr_leaks
) {
7692 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
7695 verbose(env
, "R%d pointer %s pointer prohibited\n",
7697 bpf_alu_string
[opcode
>> 4]);
7700 /* scalar += pointer
7701 * This is legal, but we have to reverse our
7702 * src/dest handling in computing the range
7704 err
= mark_chain_precision(env
, insn
->dst_reg
);
7707 return adjust_ptr_min_max_vals(env
, insn
,
7710 } else if (ptr_reg
) {
7711 /* pointer += scalar */
7712 err
= mark_chain_precision(env
, insn
->src_reg
);
7715 return adjust_ptr_min_max_vals(env
, insn
,
7719 /* Pretend the src is a reg with a known value, since we only
7720 * need to be able to read from this state.
7722 off_reg
.type
= SCALAR_VALUE
;
7723 __mark_reg_known(&off_reg
, insn
->imm
);
7725 if (ptr_reg
) /* pointer += K */
7726 return adjust_ptr_min_max_vals(env
, insn
,
7730 /* Got here implies adding two SCALAR_VALUEs */
7731 if (WARN_ON_ONCE(ptr_reg
)) {
7732 print_verifier_state(env
, state
);
7733 verbose(env
, "verifier internal error: unexpected ptr_reg\n");
7736 if (WARN_ON(!src_reg
)) {
7737 print_verifier_state(env
, state
);
7738 verbose(env
, "verifier internal error: no src_reg\n");
7741 return adjust_scalar_min_max_vals(env
, insn
, dst_reg
, *src_reg
);
7744 /* check validity of 32-bit and 64-bit arithmetic operations */
7745 static int check_alu_op(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
7747 struct bpf_reg_state
*regs
= cur_regs(env
);
7748 u8 opcode
= BPF_OP(insn
->code
);
7751 if (opcode
== BPF_END
|| opcode
== BPF_NEG
) {
7752 if (opcode
== BPF_NEG
) {
7753 if (BPF_SRC(insn
->code
) != 0 ||
7754 insn
->src_reg
!= BPF_REG_0
||
7755 insn
->off
!= 0 || insn
->imm
!= 0) {
7756 verbose(env
, "BPF_NEG uses reserved fields\n");
7760 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0 ||
7761 (insn
->imm
!= 16 && insn
->imm
!= 32 && insn
->imm
!= 64) ||
7762 BPF_CLASS(insn
->code
) == BPF_ALU64
) {
7763 verbose(env
, "BPF_END uses reserved fields\n");
7768 /* check src operand */
7769 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
7773 if (is_pointer_value(env
, insn
->dst_reg
)) {
7774 verbose(env
, "R%d pointer arithmetic prohibited\n",
7779 /* check dest operand */
7780 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP
);
7784 } else if (opcode
== BPF_MOV
) {
7786 if (BPF_SRC(insn
->code
) == BPF_X
) {
7787 if (insn
->imm
!= 0 || insn
->off
!= 0) {
7788 verbose(env
, "BPF_MOV uses reserved fields\n");
7792 /* check src operand */
7793 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
7797 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0) {
7798 verbose(env
, "BPF_MOV uses reserved fields\n");
7803 /* check dest operand, mark as required later */
7804 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
7808 if (BPF_SRC(insn
->code
) == BPF_X
) {
7809 struct bpf_reg_state
*src_reg
= regs
+ insn
->src_reg
;
7810 struct bpf_reg_state
*dst_reg
= regs
+ insn
->dst_reg
;
7812 if (BPF_CLASS(insn
->code
) == BPF_ALU64
) {
7814 * copy register state to dest reg
7816 if (src_reg
->type
== SCALAR_VALUE
&& !src_reg
->id
)
7817 /* Assign src and dst registers the same ID
7818 * that will be used by find_equal_scalars()
7819 * to propagate min/max range.
7821 src_reg
->id
= ++env
->id_gen
;
7822 *dst_reg
= *src_reg
;
7823 dst_reg
->live
|= REG_LIVE_WRITTEN
;
7824 dst_reg
->subreg_def
= DEF_NOT_SUBREG
;
7827 if (is_pointer_value(env
, insn
->src_reg
)) {
7829 "R%d partial copy of pointer\n",
7832 } else if (src_reg
->type
== SCALAR_VALUE
) {
7833 *dst_reg
= *src_reg
;
7834 /* Make sure ID is cleared otherwise
7835 * dst_reg min/max could be incorrectly
7836 * propagated into src_reg by find_equal_scalars()
7839 dst_reg
->live
|= REG_LIVE_WRITTEN
;
7840 dst_reg
->subreg_def
= env
->insn_idx
+ 1;
7842 mark_reg_unknown(env
, regs
,
7845 zext_32_to_64(dst_reg
);
7849 * remember the value we stored into this reg
7851 /* clear any state __mark_reg_known doesn't set */
7852 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
7853 regs
[insn
->dst_reg
].type
= SCALAR_VALUE
;
7854 if (BPF_CLASS(insn
->code
) == BPF_ALU64
) {
7855 __mark_reg_known(regs
+ insn
->dst_reg
,
7858 __mark_reg_known(regs
+ insn
->dst_reg
,
7863 } else if (opcode
> BPF_END
) {
7864 verbose(env
, "invalid BPF_ALU opcode %x\n", opcode
);
7867 } else { /* all other ALU ops: and, sub, xor, add, ... */
7869 if (BPF_SRC(insn
->code
) == BPF_X
) {
7870 if (insn
->imm
!= 0 || insn
->off
!= 0) {
7871 verbose(env
, "BPF_ALU uses reserved fields\n");
7874 /* check src1 operand */
7875 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
7879 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0) {
7880 verbose(env
, "BPF_ALU uses reserved fields\n");
7885 /* check src2 operand */
7886 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
7890 if ((opcode
== BPF_MOD
|| opcode
== BPF_DIV
) &&
7891 BPF_SRC(insn
->code
) == BPF_K
&& insn
->imm
== 0) {
7892 verbose(env
, "div by zero\n");
7896 if ((opcode
== BPF_LSH
|| opcode
== BPF_RSH
||
7897 opcode
== BPF_ARSH
) && BPF_SRC(insn
->code
) == BPF_K
) {
7898 int size
= BPF_CLASS(insn
->code
) == BPF_ALU64
? 64 : 32;
7900 if (insn
->imm
< 0 || insn
->imm
>= size
) {
7901 verbose(env
, "invalid shift %d\n", insn
->imm
);
7906 /* check dest operand */
7907 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
7911 return adjust_reg_min_max_vals(env
, insn
);
7917 static void __find_good_pkt_pointers(struct bpf_func_state
*state
,
7918 struct bpf_reg_state
*dst_reg
,
7919 enum bpf_reg_type type
, int new_range
)
7921 struct bpf_reg_state
*reg
;
7924 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
7925 reg
= &state
->regs
[i
];
7926 if (reg
->type
== type
&& reg
->id
== dst_reg
->id
)
7927 /* keep the maximum range already checked */
7928 reg
->range
= max(reg
->range
, new_range
);
7931 bpf_for_each_spilled_reg(i
, state
, reg
) {
7934 if (reg
->type
== type
&& reg
->id
== dst_reg
->id
)
7935 reg
->range
= max(reg
->range
, new_range
);
7939 static void find_good_pkt_pointers(struct bpf_verifier_state
*vstate
,
7940 struct bpf_reg_state
*dst_reg
,
7941 enum bpf_reg_type type
,
7942 bool range_right_open
)
7946 if (dst_reg
->off
< 0 ||
7947 (dst_reg
->off
== 0 && range_right_open
))
7948 /* This doesn't give us any range */
7951 if (dst_reg
->umax_value
> MAX_PACKET_OFF
||
7952 dst_reg
->umax_value
+ dst_reg
->off
> MAX_PACKET_OFF
)
7953 /* Risk of overflow. For instance, ptr + (1<<63) may be less
7954 * than pkt_end, but that's because it's also less than pkt.
7958 new_range
= dst_reg
->off
;
7959 if (range_right_open
)
7962 /* Examples for register markings:
7964 * pkt_data in dst register:
7968 * if (r2 > pkt_end) goto <handle exception>
7973 * if (r2 < pkt_end) goto <access okay>
7974 * <handle exception>
7977 * r2 == dst_reg, pkt_end == src_reg
7978 * r2=pkt(id=n,off=8,r=0)
7979 * r3=pkt(id=n,off=0,r=0)
7981 * pkt_data in src register:
7985 * if (pkt_end >= r2) goto <access okay>
7986 * <handle exception>
7990 * if (pkt_end <= r2) goto <handle exception>
7994 * pkt_end == dst_reg, r2 == src_reg
7995 * r2=pkt(id=n,off=8,r=0)
7996 * r3=pkt(id=n,off=0,r=0)
7998 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
7999 * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
8000 * and [r3, r3 + 8-1) respectively is safe to access depending on
8004 /* If our ids match, then we must have the same max_value. And we
8005 * don't care about the other reg's fixed offset, since if it's too big
8006 * the range won't allow anything.
8007 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
8009 for (i
= 0; i
<= vstate
->curframe
; i
++)
8010 __find_good_pkt_pointers(vstate
->frame
[i
], dst_reg
, type
,
8014 static int is_branch32_taken(struct bpf_reg_state
*reg
, u32 val
, u8 opcode
)
8016 struct tnum subreg
= tnum_subreg(reg
->var_off
);
8017 s32 sval
= (s32
)val
;
8021 if (tnum_is_const(subreg
))
8022 return !!tnum_equals_const(subreg
, val
);
8025 if (tnum_is_const(subreg
))
8026 return !tnum_equals_const(subreg
, val
);
8029 if ((~subreg
.mask
& subreg
.value
) & val
)
8031 if (!((subreg
.mask
| subreg
.value
) & val
))
8035 if (reg
->u32_min_value
> val
)
8037 else if (reg
->u32_max_value
<= val
)
8041 if (reg
->s32_min_value
> sval
)
8043 else if (reg
->s32_max_value
<= sval
)
8047 if (reg
->u32_max_value
< val
)
8049 else if (reg
->u32_min_value
>= val
)
8053 if (reg
->s32_max_value
< sval
)
8055 else if (reg
->s32_min_value
>= sval
)
8059 if (reg
->u32_min_value
>= val
)
8061 else if (reg
->u32_max_value
< val
)
8065 if (reg
->s32_min_value
>= sval
)
8067 else if (reg
->s32_max_value
< sval
)
8071 if (reg
->u32_max_value
<= val
)
8073 else if (reg
->u32_min_value
> val
)
8077 if (reg
->s32_max_value
<= sval
)
8079 else if (reg
->s32_min_value
> sval
)
8088 static int is_branch64_taken(struct bpf_reg_state
*reg
, u64 val
, u8 opcode
)
8090 s64 sval
= (s64
)val
;
8094 if (tnum_is_const(reg
->var_off
))
8095 return !!tnum_equals_const(reg
->var_off
, val
);
8098 if (tnum_is_const(reg
->var_off
))
8099 return !tnum_equals_const(reg
->var_off
, val
);
8102 if ((~reg
->var_off
.mask
& reg
->var_off
.value
) & val
)
8104 if (!((reg
->var_off
.mask
| reg
->var_off
.value
) & val
))
8108 if (reg
->umin_value
> val
)
8110 else if (reg
->umax_value
<= val
)
8114 if (reg
->smin_value
> sval
)
8116 else if (reg
->smax_value
<= sval
)
8120 if (reg
->umax_value
< val
)
8122 else if (reg
->umin_value
>= val
)
8126 if (reg
->smax_value
< sval
)
8128 else if (reg
->smin_value
>= sval
)
8132 if (reg
->umin_value
>= val
)
8134 else if (reg
->umax_value
< val
)
8138 if (reg
->smin_value
>= sval
)
8140 else if (reg
->smax_value
< sval
)
8144 if (reg
->umax_value
<= val
)
8146 else if (reg
->umin_value
> val
)
8150 if (reg
->smax_value
<= sval
)
8152 else if (reg
->smin_value
> sval
)
8160 /* compute branch direction of the expression "if (reg opcode val) goto target;"
8162 * 1 - branch will be taken and "goto target" will be executed
8163 * 0 - branch will not be taken and fall-through to next insn
8164 * -1 - unknown. Example: "if (reg < 5)" is unknown when register value
8167 static int is_branch_taken(struct bpf_reg_state
*reg
, u64 val
, u8 opcode
,
8170 if (__is_pointer_value(false, reg
)) {
8171 if (!reg_type_not_null(reg
->type
))
8174 /* If pointer is valid tests against zero will fail so we can
8175 * use this to direct branch taken.
8191 return is_branch32_taken(reg
, val
, opcode
);
8192 return is_branch64_taken(reg
, val
, opcode
);
8195 static int flip_opcode(u32 opcode
)
8197 /* How can we transform "a <op> b" into "b <op> a"? */
8198 static const u8 opcode_flip
[16] = {
8199 /* these stay the same */
8200 [BPF_JEQ
>> 4] = BPF_JEQ
,
8201 [BPF_JNE
>> 4] = BPF_JNE
,
8202 [BPF_JSET
>> 4] = BPF_JSET
,
8203 /* these swap "lesser" and "greater" (L and G in the opcodes) */
8204 [BPF_JGE
>> 4] = BPF_JLE
,
8205 [BPF_JGT
>> 4] = BPF_JLT
,
8206 [BPF_JLE
>> 4] = BPF_JGE
,
8207 [BPF_JLT
>> 4] = BPF_JGT
,
8208 [BPF_JSGE
>> 4] = BPF_JSLE
,
8209 [BPF_JSGT
>> 4] = BPF_JSLT
,
8210 [BPF_JSLE
>> 4] = BPF_JSGE
,
8211 [BPF_JSLT
>> 4] = BPF_JSGT
8213 return opcode_flip
[opcode
>> 4];
8216 static int is_pkt_ptr_branch_taken(struct bpf_reg_state
*dst_reg
,
8217 struct bpf_reg_state
*src_reg
,
8220 struct bpf_reg_state
*pkt
;
8222 if (src_reg
->type
== PTR_TO_PACKET_END
) {
8224 } else if (dst_reg
->type
== PTR_TO_PACKET_END
) {
8226 opcode
= flip_opcode(opcode
);
8231 if (pkt
->range
>= 0)
8236 /* pkt <= pkt_end */
8240 if (pkt
->range
== BEYOND_PKT_END
)
8241 /* pkt has at last one extra byte beyond pkt_end */
8242 return opcode
== BPF_JGT
;
8248 /* pkt >= pkt_end */
8249 if (pkt
->range
== BEYOND_PKT_END
|| pkt
->range
== AT_PKT_END
)
8250 return opcode
== BPF_JGE
;
8256 /* Adjusts the register min/max values in the case that the dst_reg is the
8257 * variable register that we are working on, and src_reg is a constant or we're
8258 * simply doing a BPF_K check.
8259 * In JEQ/JNE cases we also adjust the var_off values.
8261 static void reg_set_min_max(struct bpf_reg_state
*true_reg
,
8262 struct bpf_reg_state
*false_reg
,
8264 u8 opcode
, bool is_jmp32
)
8266 struct tnum false_32off
= tnum_subreg(false_reg
->var_off
);
8267 struct tnum false_64off
= false_reg
->var_off
;
8268 struct tnum true_32off
= tnum_subreg(true_reg
->var_off
);
8269 struct tnum true_64off
= true_reg
->var_off
;
8270 s64 sval
= (s64
)val
;
8271 s32 sval32
= (s32
)val32
;
8273 /* If the dst_reg is a pointer, we can't learn anything about its
8274 * variable offset from the compare (unless src_reg were a pointer into
8275 * the same object, but we don't bother with that.
8276 * Since false_reg and true_reg have the same type by construction, we
8277 * only need to check one of them for pointerness.
8279 if (__is_pointer_value(false, false_reg
))
8286 struct bpf_reg_state
*reg
=
8287 opcode
== BPF_JEQ
? true_reg
: false_reg
;
8289 /* JEQ/JNE comparison doesn't change the register equivalence.
8291 * if (r1 == 42) goto label;
8293 * label: // here both r1 and r2 are known to be 42.
8295 * Hence when marking register as known preserve it's ID.
8298 __mark_reg32_known(reg
, val32
);
8300 ___mark_reg_known(reg
, val
);
8305 false_32off
= tnum_and(false_32off
, tnum_const(~val32
));
8306 if (is_power_of_2(val32
))
8307 true_32off
= tnum_or(true_32off
,
8310 false_64off
= tnum_and(false_64off
, tnum_const(~val
));
8311 if (is_power_of_2(val
))
8312 true_64off
= tnum_or(true_64off
,
8320 u32 false_umax
= opcode
== BPF_JGT
? val32
: val32
- 1;
8321 u32 true_umin
= opcode
== BPF_JGT
? val32
+ 1 : val32
;
8323 false_reg
->u32_max_value
= min(false_reg
->u32_max_value
,
8325 true_reg
->u32_min_value
= max(true_reg
->u32_min_value
,
8328 u64 false_umax
= opcode
== BPF_JGT
? val
: val
- 1;
8329 u64 true_umin
= opcode
== BPF_JGT
? val
+ 1 : val
;
8331 false_reg
->umax_value
= min(false_reg
->umax_value
, false_umax
);
8332 true_reg
->umin_value
= max(true_reg
->umin_value
, true_umin
);
8340 s32 false_smax
= opcode
== BPF_JSGT
? sval32
: sval32
- 1;
8341 s32 true_smin
= opcode
== BPF_JSGT
? sval32
+ 1 : sval32
;
8343 false_reg
->s32_max_value
= min(false_reg
->s32_max_value
, false_smax
);
8344 true_reg
->s32_min_value
= max(true_reg
->s32_min_value
, true_smin
);
8346 s64 false_smax
= opcode
== BPF_JSGT
? sval
: sval
- 1;
8347 s64 true_smin
= opcode
== BPF_JSGT
? sval
+ 1 : sval
;
8349 false_reg
->smax_value
= min(false_reg
->smax_value
, false_smax
);
8350 true_reg
->smin_value
= max(true_reg
->smin_value
, true_smin
);
8358 u32 false_umin
= opcode
== BPF_JLT
? val32
: val32
+ 1;
8359 u32 true_umax
= opcode
== BPF_JLT
? val32
- 1 : val32
;
8361 false_reg
->u32_min_value
= max(false_reg
->u32_min_value
,
8363 true_reg
->u32_max_value
= min(true_reg
->u32_max_value
,
8366 u64 false_umin
= opcode
== BPF_JLT
? val
: val
+ 1;
8367 u64 true_umax
= opcode
== BPF_JLT
? val
- 1 : val
;
8369 false_reg
->umin_value
= max(false_reg
->umin_value
, false_umin
);
8370 true_reg
->umax_value
= min(true_reg
->umax_value
, true_umax
);
8378 s32 false_smin
= opcode
== BPF_JSLT
? sval32
: sval32
+ 1;
8379 s32 true_smax
= opcode
== BPF_JSLT
? sval32
- 1 : sval32
;
8381 false_reg
->s32_min_value
= max(false_reg
->s32_min_value
, false_smin
);
8382 true_reg
->s32_max_value
= min(true_reg
->s32_max_value
, true_smax
);
8384 s64 false_smin
= opcode
== BPF_JSLT
? sval
: sval
+ 1;
8385 s64 true_smax
= opcode
== BPF_JSLT
? sval
- 1 : sval
;
8387 false_reg
->smin_value
= max(false_reg
->smin_value
, false_smin
);
8388 true_reg
->smax_value
= min(true_reg
->smax_value
, true_smax
);
8397 false_reg
->var_off
= tnum_or(tnum_clear_subreg(false_64off
),
8398 tnum_subreg(false_32off
));
8399 true_reg
->var_off
= tnum_or(tnum_clear_subreg(true_64off
),
8400 tnum_subreg(true_32off
));
8401 __reg_combine_32_into_64(false_reg
);
8402 __reg_combine_32_into_64(true_reg
);
8404 false_reg
->var_off
= false_64off
;
8405 true_reg
->var_off
= true_64off
;
8406 __reg_combine_64_into_32(false_reg
);
8407 __reg_combine_64_into_32(true_reg
);
8411 /* Same as above, but for the case that dst_reg holds a constant and src_reg is
8414 static void reg_set_min_max_inv(struct bpf_reg_state
*true_reg
,
8415 struct bpf_reg_state
*false_reg
,
8417 u8 opcode
, bool is_jmp32
)
8419 opcode
= flip_opcode(opcode
);
8420 /* This uses zero as "not present in table"; luckily the zero opcode,
8421 * BPF_JA, can't get here.
8424 reg_set_min_max(true_reg
, false_reg
, val
, val32
, opcode
, is_jmp32
);
8427 /* Regs are known to be equal, so intersect their min/max/var_off */
8428 static void __reg_combine_min_max(struct bpf_reg_state
*src_reg
,
8429 struct bpf_reg_state
*dst_reg
)
8431 src_reg
->umin_value
= dst_reg
->umin_value
= max(src_reg
->umin_value
,
8432 dst_reg
->umin_value
);
8433 src_reg
->umax_value
= dst_reg
->umax_value
= min(src_reg
->umax_value
,
8434 dst_reg
->umax_value
);
8435 src_reg
->smin_value
= dst_reg
->smin_value
= max(src_reg
->smin_value
,
8436 dst_reg
->smin_value
);
8437 src_reg
->smax_value
= dst_reg
->smax_value
= min(src_reg
->smax_value
,
8438 dst_reg
->smax_value
);
8439 src_reg
->var_off
= dst_reg
->var_off
= tnum_intersect(src_reg
->var_off
,
8441 /* We might have learned new bounds from the var_off. */
8442 __update_reg_bounds(src_reg
);
8443 __update_reg_bounds(dst_reg
);
8444 /* We might have learned something about the sign bit. */
8445 __reg_deduce_bounds(src_reg
);
8446 __reg_deduce_bounds(dst_reg
);
8447 /* We might have learned some bits from the bounds. */
8448 __reg_bound_offset(src_reg
);
8449 __reg_bound_offset(dst_reg
);
8450 /* Intersecting with the old var_off might have improved our bounds
8451 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
8452 * then new var_off is (0; 0x7f...fc) which improves our umax.
8454 __update_reg_bounds(src_reg
);
8455 __update_reg_bounds(dst_reg
);
8458 static void reg_combine_min_max(struct bpf_reg_state
*true_src
,
8459 struct bpf_reg_state
*true_dst
,
8460 struct bpf_reg_state
*false_src
,
8461 struct bpf_reg_state
*false_dst
,
8466 __reg_combine_min_max(true_src
, true_dst
);
8469 __reg_combine_min_max(false_src
, false_dst
);
8474 static void mark_ptr_or_null_reg(struct bpf_func_state
*state
,
8475 struct bpf_reg_state
*reg
, u32 id
,
8478 if (reg_type_may_be_null(reg
->type
) && reg
->id
== id
&&
8479 !WARN_ON_ONCE(!reg
->id
)) {
8480 /* Old offset (both fixed and variable parts) should
8481 * have been known-zero, because we don't allow pointer
8482 * arithmetic on pointers that might be NULL.
8484 if (WARN_ON_ONCE(reg
->smin_value
|| reg
->smax_value
||
8485 !tnum_equals_const(reg
->var_off
, 0) ||
8487 __mark_reg_known_zero(reg
);
8491 reg
->type
= SCALAR_VALUE
;
8492 /* We don't need id and ref_obj_id from this point
8493 * onwards anymore, thus we should better reset it,
8494 * so that state pruning has chances to take effect.
8497 reg
->ref_obj_id
= 0;
8502 mark_ptr_not_null_reg(reg
);
8504 if (!reg_may_point_to_spin_lock(reg
)) {
8505 /* For not-NULL ptr, reg->ref_obj_id will be reset
8506 * in release_reg_references().
8508 * reg->id is still used by spin_lock ptr. Other
8509 * than spin_lock ptr type, reg->id can be reset.
8516 static void __mark_ptr_or_null_regs(struct bpf_func_state
*state
, u32 id
,
8519 struct bpf_reg_state
*reg
;
8522 for (i
= 0; i
< MAX_BPF_REG
; i
++)
8523 mark_ptr_or_null_reg(state
, &state
->regs
[i
], id
, is_null
);
8525 bpf_for_each_spilled_reg(i
, state
, reg
) {
8528 mark_ptr_or_null_reg(state
, reg
, id
, is_null
);
8532 /* The logic is similar to find_good_pkt_pointers(), both could eventually
8533 * be folded together at some point.
8535 static void mark_ptr_or_null_regs(struct bpf_verifier_state
*vstate
, u32 regno
,
8538 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
8539 struct bpf_reg_state
*regs
= state
->regs
;
8540 u32 ref_obj_id
= regs
[regno
].ref_obj_id
;
8541 u32 id
= regs
[regno
].id
;
8544 if (ref_obj_id
&& ref_obj_id
== id
&& is_null
)
8545 /* regs[regno] is in the " == NULL" branch.
8546 * No one could have freed the reference state before
8547 * doing the NULL check.
8549 WARN_ON_ONCE(release_reference_state(state
, id
));
8551 for (i
= 0; i
<= vstate
->curframe
; i
++)
8552 __mark_ptr_or_null_regs(vstate
->frame
[i
], id
, is_null
);
8555 static bool try_match_pkt_pointers(const struct bpf_insn
*insn
,
8556 struct bpf_reg_state
*dst_reg
,
8557 struct bpf_reg_state
*src_reg
,
8558 struct bpf_verifier_state
*this_branch
,
8559 struct bpf_verifier_state
*other_branch
)
8561 if (BPF_SRC(insn
->code
) != BPF_X
)
8564 /* Pointers are always 64-bit. */
8565 if (BPF_CLASS(insn
->code
) == BPF_JMP32
)
8568 switch (BPF_OP(insn
->code
)) {
8570 if ((dst_reg
->type
== PTR_TO_PACKET
&&
8571 src_reg
->type
== PTR_TO_PACKET_END
) ||
8572 (dst_reg
->type
== PTR_TO_PACKET_META
&&
8573 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
8574 /* pkt_data' > pkt_end, pkt_meta' > pkt_data */
8575 find_good_pkt_pointers(this_branch
, dst_reg
,
8576 dst_reg
->type
, false);
8577 mark_pkt_end(other_branch
, insn
->dst_reg
, true);
8578 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
8579 src_reg
->type
== PTR_TO_PACKET
) ||
8580 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
8581 src_reg
->type
== PTR_TO_PACKET_META
)) {
8582 /* pkt_end > pkt_data', pkt_data > pkt_meta' */
8583 find_good_pkt_pointers(other_branch
, src_reg
,
8584 src_reg
->type
, true);
8585 mark_pkt_end(this_branch
, insn
->src_reg
, false);
8591 if ((dst_reg
->type
== PTR_TO_PACKET
&&
8592 src_reg
->type
== PTR_TO_PACKET_END
) ||
8593 (dst_reg
->type
== PTR_TO_PACKET_META
&&
8594 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
8595 /* pkt_data' < pkt_end, pkt_meta' < pkt_data */
8596 find_good_pkt_pointers(other_branch
, dst_reg
,
8597 dst_reg
->type
, true);
8598 mark_pkt_end(this_branch
, insn
->dst_reg
, false);
8599 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
8600 src_reg
->type
== PTR_TO_PACKET
) ||
8601 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
8602 src_reg
->type
== PTR_TO_PACKET_META
)) {
8603 /* pkt_end < pkt_data', pkt_data > pkt_meta' */
8604 find_good_pkt_pointers(this_branch
, src_reg
,
8605 src_reg
->type
, false);
8606 mark_pkt_end(other_branch
, insn
->src_reg
, true);
8612 if ((dst_reg
->type
== PTR_TO_PACKET
&&
8613 src_reg
->type
== PTR_TO_PACKET_END
) ||
8614 (dst_reg
->type
== PTR_TO_PACKET_META
&&
8615 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
8616 /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
8617 find_good_pkt_pointers(this_branch
, dst_reg
,
8618 dst_reg
->type
, true);
8619 mark_pkt_end(other_branch
, insn
->dst_reg
, false);
8620 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
8621 src_reg
->type
== PTR_TO_PACKET
) ||
8622 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
8623 src_reg
->type
== PTR_TO_PACKET_META
)) {
8624 /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
8625 find_good_pkt_pointers(other_branch
, src_reg
,
8626 src_reg
->type
, false);
8627 mark_pkt_end(this_branch
, insn
->src_reg
, true);
8633 if ((dst_reg
->type
== PTR_TO_PACKET
&&
8634 src_reg
->type
== PTR_TO_PACKET_END
) ||
8635 (dst_reg
->type
== PTR_TO_PACKET_META
&&
8636 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
8637 /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
8638 find_good_pkt_pointers(other_branch
, dst_reg
,
8639 dst_reg
->type
, false);
8640 mark_pkt_end(this_branch
, insn
->dst_reg
, true);
8641 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
8642 src_reg
->type
== PTR_TO_PACKET
) ||
8643 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
8644 src_reg
->type
== PTR_TO_PACKET_META
)) {
8645 /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
8646 find_good_pkt_pointers(this_branch
, src_reg
,
8647 src_reg
->type
, true);
8648 mark_pkt_end(other_branch
, insn
->src_reg
, false);
8660 static void find_equal_scalars(struct bpf_verifier_state
*vstate
,
8661 struct bpf_reg_state
*known_reg
)
8663 struct bpf_func_state
*state
;
8664 struct bpf_reg_state
*reg
;
8667 for (i
= 0; i
<= vstate
->curframe
; i
++) {
8668 state
= vstate
->frame
[i
];
8669 for (j
= 0; j
< MAX_BPF_REG
; j
++) {
8670 reg
= &state
->regs
[j
];
8671 if (reg
->type
== SCALAR_VALUE
&& reg
->id
== known_reg
->id
)
8675 bpf_for_each_spilled_reg(j
, state
, reg
) {
8678 if (reg
->type
== SCALAR_VALUE
&& reg
->id
== known_reg
->id
)
8684 static int check_cond_jmp_op(struct bpf_verifier_env
*env
,
8685 struct bpf_insn
*insn
, int *insn_idx
)
8687 struct bpf_verifier_state
*this_branch
= env
->cur_state
;
8688 struct bpf_verifier_state
*other_branch
;
8689 struct bpf_reg_state
*regs
= this_branch
->frame
[this_branch
->curframe
]->regs
;
8690 struct bpf_reg_state
*dst_reg
, *other_branch_regs
, *src_reg
= NULL
;
8691 u8 opcode
= BPF_OP(insn
->code
);
8696 /* Only conditional jumps are expected to reach here. */
8697 if (opcode
== BPF_JA
|| opcode
> BPF_JSLE
) {
8698 verbose(env
, "invalid BPF_JMP/JMP32 opcode %x\n", opcode
);
8702 if (BPF_SRC(insn
->code
) == BPF_X
) {
8703 if (insn
->imm
!= 0) {
8704 verbose(env
, "BPF_JMP/JMP32 uses reserved fields\n");
8708 /* check src1 operand */
8709 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
8713 if (is_pointer_value(env
, insn
->src_reg
)) {
8714 verbose(env
, "R%d pointer comparison prohibited\n",
8718 src_reg
= ®s
[insn
->src_reg
];
8720 if (insn
->src_reg
!= BPF_REG_0
) {
8721 verbose(env
, "BPF_JMP/JMP32 uses reserved fields\n");
8726 /* check src2 operand */
8727 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
8731 dst_reg
= ®s
[insn
->dst_reg
];
8732 is_jmp32
= BPF_CLASS(insn
->code
) == BPF_JMP32
;
8734 if (BPF_SRC(insn
->code
) == BPF_K
) {
8735 pred
= is_branch_taken(dst_reg
, insn
->imm
, opcode
, is_jmp32
);
8736 } else if (src_reg
->type
== SCALAR_VALUE
&&
8737 is_jmp32
&& tnum_is_const(tnum_subreg(src_reg
->var_off
))) {
8738 pred
= is_branch_taken(dst_reg
,
8739 tnum_subreg(src_reg
->var_off
).value
,
8742 } else if (src_reg
->type
== SCALAR_VALUE
&&
8743 !is_jmp32
&& tnum_is_const(src_reg
->var_off
)) {
8744 pred
= is_branch_taken(dst_reg
,
8745 src_reg
->var_off
.value
,
8748 } else if (reg_is_pkt_pointer_any(dst_reg
) &&
8749 reg_is_pkt_pointer_any(src_reg
) &&
8751 pred
= is_pkt_ptr_branch_taken(dst_reg
, src_reg
, opcode
);
8755 /* If we get here with a dst_reg pointer type it is because
8756 * above is_branch_taken() special cased the 0 comparison.
8758 if (!__is_pointer_value(false, dst_reg
))
8759 err
= mark_chain_precision(env
, insn
->dst_reg
);
8760 if (BPF_SRC(insn
->code
) == BPF_X
&& !err
&&
8761 !__is_pointer_value(false, src_reg
))
8762 err
= mark_chain_precision(env
, insn
->src_reg
);
8767 /* only follow the goto, ignore fall-through */
8768 *insn_idx
+= insn
->off
;
8770 } else if (pred
== 0) {
8771 /* only follow fall-through branch, since
8772 * that's where the program will go
8777 other_branch
= push_stack(env
, *insn_idx
+ insn
->off
+ 1, *insn_idx
,
8781 other_branch_regs
= other_branch
->frame
[other_branch
->curframe
]->regs
;
8783 /* detect if we are comparing against a constant value so we can adjust
8784 * our min/max values for our dst register.
8785 * this is only legit if both are scalars (or pointers to the same
8786 * object, I suppose, but we don't support that right now), because
8787 * otherwise the different base pointers mean the offsets aren't
8790 if (BPF_SRC(insn
->code
) == BPF_X
) {
8791 struct bpf_reg_state
*src_reg
= ®s
[insn
->src_reg
];
8793 if (dst_reg
->type
== SCALAR_VALUE
&&
8794 src_reg
->type
== SCALAR_VALUE
) {
8795 if (tnum_is_const(src_reg
->var_off
) ||
8797 tnum_is_const(tnum_subreg(src_reg
->var_off
))))
8798 reg_set_min_max(&other_branch_regs
[insn
->dst_reg
],
8800 src_reg
->var_off
.value
,
8801 tnum_subreg(src_reg
->var_off
).value
,
8803 else if (tnum_is_const(dst_reg
->var_off
) ||
8805 tnum_is_const(tnum_subreg(dst_reg
->var_off
))))
8806 reg_set_min_max_inv(&other_branch_regs
[insn
->src_reg
],
8808 dst_reg
->var_off
.value
,
8809 tnum_subreg(dst_reg
->var_off
).value
,
8811 else if (!is_jmp32
&&
8812 (opcode
== BPF_JEQ
|| opcode
== BPF_JNE
))
8813 /* Comparing for equality, we can combine knowledge */
8814 reg_combine_min_max(&other_branch_regs
[insn
->src_reg
],
8815 &other_branch_regs
[insn
->dst_reg
],
8816 src_reg
, dst_reg
, opcode
);
8818 !WARN_ON_ONCE(src_reg
->id
!= other_branch_regs
[insn
->src_reg
].id
)) {
8819 find_equal_scalars(this_branch
, src_reg
);
8820 find_equal_scalars(other_branch
, &other_branch_regs
[insn
->src_reg
]);
8824 } else if (dst_reg
->type
== SCALAR_VALUE
) {
8825 reg_set_min_max(&other_branch_regs
[insn
->dst_reg
],
8826 dst_reg
, insn
->imm
, (u32
)insn
->imm
,
8830 if (dst_reg
->type
== SCALAR_VALUE
&& dst_reg
->id
&&
8831 !WARN_ON_ONCE(dst_reg
->id
!= other_branch_regs
[insn
->dst_reg
].id
)) {
8832 find_equal_scalars(this_branch
, dst_reg
);
8833 find_equal_scalars(other_branch
, &other_branch_regs
[insn
->dst_reg
]);
8836 /* detect if R == 0 where R is returned from bpf_map_lookup_elem().
8837 * NOTE: these optimizations below are related with pointer comparison
8838 * which will never be JMP32.
8840 if (!is_jmp32
&& BPF_SRC(insn
->code
) == BPF_K
&&
8841 insn
->imm
== 0 && (opcode
== BPF_JEQ
|| opcode
== BPF_JNE
) &&
8842 reg_type_may_be_null(dst_reg
->type
)) {
8843 /* Mark all identical registers in each branch as either
8844 * safe or unknown depending R == 0 or R != 0 conditional.
8846 mark_ptr_or_null_regs(this_branch
, insn
->dst_reg
,
8848 mark_ptr_or_null_regs(other_branch
, insn
->dst_reg
,
8850 } else if (!try_match_pkt_pointers(insn
, dst_reg
, ®s
[insn
->src_reg
],
8851 this_branch
, other_branch
) &&
8852 is_pointer_value(env
, insn
->dst_reg
)) {
8853 verbose(env
, "R%d pointer comparison prohibited\n",
8857 if (env
->log
.level
& BPF_LOG_LEVEL
)
8858 print_verifier_state(env
, this_branch
->frame
[this_branch
->curframe
]);
8862 /* verify BPF_LD_IMM64 instruction */
8863 static int check_ld_imm(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
8865 struct bpf_insn_aux_data
*aux
= cur_aux(env
);
8866 struct bpf_reg_state
*regs
= cur_regs(env
);
8867 struct bpf_reg_state
*dst_reg
;
8868 struct bpf_map
*map
;
8871 if (BPF_SIZE(insn
->code
) != BPF_DW
) {
8872 verbose(env
, "invalid BPF_LD_IMM insn\n");
8875 if (insn
->off
!= 0) {
8876 verbose(env
, "BPF_LD_IMM64 uses reserved fields\n");
8880 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP
);
8884 dst_reg
= ®s
[insn
->dst_reg
];
8885 if (insn
->src_reg
== 0) {
8886 u64 imm
= ((u64
)(insn
+ 1)->imm
<< 32) | (u32
)insn
->imm
;
8888 dst_reg
->type
= SCALAR_VALUE
;
8889 __mark_reg_known(®s
[insn
->dst_reg
], imm
);
8893 if (insn
->src_reg
== BPF_PSEUDO_BTF_ID
) {
8894 mark_reg_known_zero(env
, regs
, insn
->dst_reg
);
8896 dst_reg
->type
= aux
->btf_var
.reg_type
;
8897 switch (dst_reg
->type
) {
8899 dst_reg
->mem_size
= aux
->btf_var
.mem_size
;
8902 case PTR_TO_PERCPU_BTF_ID
:
8903 dst_reg
->btf
= aux
->btf_var
.btf
;
8904 dst_reg
->btf_id
= aux
->btf_var
.btf_id
;
8907 verbose(env
, "bpf verifier is misconfigured\n");
8913 if (insn
->src_reg
== BPF_PSEUDO_FUNC
) {
8914 struct bpf_prog_aux
*aux
= env
->prog
->aux
;
8915 u32 subprogno
= insn
[1].imm
;
8917 if (!aux
->func_info
) {
8918 verbose(env
, "missing btf func_info\n");
8921 if (aux
->func_info_aux
[subprogno
].linkage
!= BTF_FUNC_STATIC
) {
8922 verbose(env
, "callback function not static\n");
8926 dst_reg
->type
= PTR_TO_FUNC
;
8927 dst_reg
->subprogno
= subprogno
;
8931 map
= env
->used_maps
[aux
->map_index
];
8932 mark_reg_known_zero(env
, regs
, insn
->dst_reg
);
8933 dst_reg
->map_ptr
= map
;
8935 if (insn
->src_reg
== BPF_PSEUDO_MAP_VALUE
) {
8936 dst_reg
->type
= PTR_TO_MAP_VALUE
;
8937 dst_reg
->off
= aux
->map_off
;
8938 if (map_value_has_spin_lock(map
))
8939 dst_reg
->id
= ++env
->id_gen
;
8940 } else if (insn
->src_reg
== BPF_PSEUDO_MAP_FD
) {
8941 dst_reg
->type
= CONST_PTR_TO_MAP
;
8943 verbose(env
, "bpf verifier is misconfigured\n");
8950 static bool may_access_skb(enum bpf_prog_type type
)
8953 case BPF_PROG_TYPE_SOCKET_FILTER
:
8954 case BPF_PROG_TYPE_SCHED_CLS
:
8955 case BPF_PROG_TYPE_SCHED_ACT
:
8962 /* verify safety of LD_ABS|LD_IND instructions:
8963 * - they can only appear in the programs where ctx == skb
8964 * - since they are wrappers of function calls, they scratch R1-R5 registers,
8965 * preserve R6-R9, and store return value into R0
8968 * ctx == skb == R6 == CTX
8971 * SRC == any register
8972 * IMM == 32-bit immediate
8975 * R0 - 8/16/32-bit skb data converted to cpu endianness
8977 static int check_ld_abs(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
8979 struct bpf_reg_state
*regs
= cur_regs(env
);
8980 static const int ctx_reg
= BPF_REG_6
;
8981 u8 mode
= BPF_MODE(insn
->code
);
8984 if (!may_access_skb(resolve_prog_type(env
->prog
))) {
8985 verbose(env
, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
8989 if (!env
->ops
->gen_ld_abs
) {
8990 verbose(env
, "bpf verifier is misconfigured\n");
8994 if (insn
->dst_reg
!= BPF_REG_0
|| insn
->off
!= 0 ||
8995 BPF_SIZE(insn
->code
) == BPF_DW
||
8996 (mode
== BPF_ABS
&& insn
->src_reg
!= BPF_REG_0
)) {
8997 verbose(env
, "BPF_LD_[ABS|IND] uses reserved fields\n");
9001 /* check whether implicit source operand (register R6) is readable */
9002 err
= check_reg_arg(env
, ctx_reg
, SRC_OP
);
9006 /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
9007 * gen_ld_abs() may terminate the program at runtime, leading to
9010 err
= check_reference_leak(env
);
9012 verbose(env
, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
9016 if (env
->cur_state
->active_spin_lock
) {
9017 verbose(env
, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
9021 if (regs
[ctx_reg
].type
!= PTR_TO_CTX
) {
9023 "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
9027 if (mode
== BPF_IND
) {
9028 /* check explicit source operand */
9029 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
9034 err
= check_ctx_reg(env
, ®s
[ctx_reg
], ctx_reg
);
9038 /* reset caller saved regs to unreadable */
9039 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
9040 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
9041 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
9044 /* mark destination R0 register as readable, since it contains
9045 * the value fetched from the packet.
9046 * Already marked as written above.
9048 mark_reg_unknown(env
, regs
, BPF_REG_0
);
9049 /* ld_abs load up to 32-bit skb data. */
9050 regs
[BPF_REG_0
].subreg_def
= env
->insn_idx
+ 1;
9054 static int check_return_code(struct bpf_verifier_env
*env
)
9056 struct tnum enforce_attach_type_range
= tnum_unknown
;
9057 const struct bpf_prog
*prog
= env
->prog
;
9058 struct bpf_reg_state
*reg
;
9059 struct tnum range
= tnum_range(0, 1);
9060 enum bpf_prog_type prog_type
= resolve_prog_type(env
->prog
);
9062 const bool is_subprog
= env
->cur_state
->frame
[0]->subprogno
;
9064 /* LSM and struct_ops func-ptr's return type could be "void" */
9066 (prog_type
== BPF_PROG_TYPE_STRUCT_OPS
||
9067 prog_type
== BPF_PROG_TYPE_LSM
) &&
9068 !prog
->aux
->attach_func_proto
->type
)
9071 /* eBPF calling convetion is such that R0 is used
9072 * to return the value from eBPF program.
9073 * Make sure that it's readable at this time
9074 * of bpf_exit, which means that program wrote
9075 * something into it earlier
9077 err
= check_reg_arg(env
, BPF_REG_0
, SRC_OP
);
9081 if (is_pointer_value(env
, BPF_REG_0
)) {
9082 verbose(env
, "R0 leaks addr as return value\n");
9086 reg
= cur_regs(env
) + BPF_REG_0
;
9088 if (reg
->type
!= SCALAR_VALUE
) {
9089 verbose(env
, "At subprogram exit the register R0 is not a scalar value (%s)\n",
9090 reg_type_str
[reg
->type
]);
9096 switch (prog_type
) {
9097 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR
:
9098 if (env
->prog
->expected_attach_type
== BPF_CGROUP_UDP4_RECVMSG
||
9099 env
->prog
->expected_attach_type
== BPF_CGROUP_UDP6_RECVMSG
||
9100 env
->prog
->expected_attach_type
== BPF_CGROUP_INET4_GETPEERNAME
||
9101 env
->prog
->expected_attach_type
== BPF_CGROUP_INET6_GETPEERNAME
||
9102 env
->prog
->expected_attach_type
== BPF_CGROUP_INET4_GETSOCKNAME
||
9103 env
->prog
->expected_attach_type
== BPF_CGROUP_INET6_GETSOCKNAME
)
9104 range
= tnum_range(1, 1);
9105 if (env
->prog
->expected_attach_type
== BPF_CGROUP_INET4_BIND
||
9106 env
->prog
->expected_attach_type
== BPF_CGROUP_INET6_BIND
)
9107 range
= tnum_range(0, 3);
9109 case BPF_PROG_TYPE_CGROUP_SKB
:
9110 if (env
->prog
->expected_attach_type
== BPF_CGROUP_INET_EGRESS
) {
9111 range
= tnum_range(0, 3);
9112 enforce_attach_type_range
= tnum_range(2, 3);
9115 case BPF_PROG_TYPE_CGROUP_SOCK
:
9116 case BPF_PROG_TYPE_SOCK_OPS
:
9117 case BPF_PROG_TYPE_CGROUP_DEVICE
:
9118 case BPF_PROG_TYPE_CGROUP_SYSCTL
:
9119 case BPF_PROG_TYPE_CGROUP_SOCKOPT
:
9121 case BPF_PROG_TYPE_RAW_TRACEPOINT
:
9122 if (!env
->prog
->aux
->attach_btf_id
)
9124 range
= tnum_const(0);
9126 case BPF_PROG_TYPE_TRACING
:
9127 switch (env
->prog
->expected_attach_type
) {
9128 case BPF_TRACE_FENTRY
:
9129 case BPF_TRACE_FEXIT
:
9130 range
= tnum_const(0);
9132 case BPF_TRACE_RAW_TP
:
9133 case BPF_MODIFY_RETURN
:
9135 case BPF_TRACE_ITER
:
9141 case BPF_PROG_TYPE_SK_LOOKUP
:
9142 range
= tnum_range(SK_DROP
, SK_PASS
);
9144 case BPF_PROG_TYPE_EXT
:
9145 /* freplace program can return anything as its return value
9146 * depends on the to-be-replaced kernel func or bpf program.
9152 if (reg
->type
!= SCALAR_VALUE
) {
9153 verbose(env
, "At program exit the register R0 is not a known value (%s)\n",
9154 reg_type_str
[reg
->type
]);
9158 if (!tnum_in(range
, reg
->var_off
)) {
9159 verbose_invalid_scalar(env
, reg
, &range
, "program exit", "R0");
9163 if (!tnum_is_unknown(enforce_attach_type_range
) &&
9164 tnum_in(enforce_attach_type_range
, reg
->var_off
))
9165 env
->prog
->enforce_expected_attach_type
= 1;
9169 /* non-recursive DFS pseudo code
9170 * 1 procedure DFS-iterative(G,v):
9171 * 2 label v as discovered
9172 * 3 let S be a stack
9174 * 5 while S is not empty
9176 * 7 if t is what we're looking for:
9178 * 9 for all edges e in G.adjacentEdges(t) do
9179 * 10 if edge e is already labelled
9180 * 11 continue with the next edge
9181 * 12 w <- G.adjacentVertex(t,e)
9182 * 13 if vertex w is not discovered and not explored
9183 * 14 label e as tree-edge
9184 * 15 label w as discovered
9187 * 18 else if vertex w is discovered
9188 * 19 label e as back-edge
9190 * 21 // vertex w is explored
9191 * 22 label e as forward- or cross-edge
9192 * 23 label t as explored
9197 * 0x11 - discovered and fall-through edge labelled
9198 * 0x12 - discovered and fall-through and branch edges labelled
9209 static u32
state_htab_size(struct bpf_verifier_env
*env
)
9211 return env
->prog
->len
;
9214 static struct bpf_verifier_state_list
**explored_state(
9215 struct bpf_verifier_env
*env
,
9218 struct bpf_verifier_state
*cur
= env
->cur_state
;
9219 struct bpf_func_state
*state
= cur
->frame
[cur
->curframe
];
9221 return &env
->explored_states
[(idx
^ state
->callsite
) % state_htab_size(env
)];
9224 static void init_explored_state(struct bpf_verifier_env
*env
, int idx
)
9226 env
->insn_aux_data
[idx
].prune_point
= true;
9234 /* t, w, e - match pseudo-code above:
9235 * t - index of current instruction
9236 * w - next instruction
9239 static int push_insn(int t
, int w
, int e
, struct bpf_verifier_env
*env
,
9242 int *insn_stack
= env
->cfg
.insn_stack
;
9243 int *insn_state
= env
->cfg
.insn_state
;
9245 if (e
== FALLTHROUGH
&& insn_state
[t
] >= (DISCOVERED
| FALLTHROUGH
))
9246 return DONE_EXPLORING
;
9248 if (e
== BRANCH
&& insn_state
[t
] >= (DISCOVERED
| BRANCH
))
9249 return DONE_EXPLORING
;
9251 if (w
< 0 || w
>= env
->prog
->len
) {
9252 verbose_linfo(env
, t
, "%d: ", t
);
9253 verbose(env
, "jump out of range from insn %d to %d\n", t
, w
);
9258 /* mark branch target for state pruning */
9259 init_explored_state(env
, w
);
9261 if (insn_state
[w
] == 0) {
9263 insn_state
[t
] = DISCOVERED
| e
;
9264 insn_state
[w
] = DISCOVERED
;
9265 if (env
->cfg
.cur_stack
>= env
->prog
->len
)
9267 insn_stack
[env
->cfg
.cur_stack
++] = w
;
9268 return KEEP_EXPLORING
;
9269 } else if ((insn_state
[w
] & 0xF0) == DISCOVERED
) {
9270 if (loop_ok
&& env
->bpf_capable
)
9271 return DONE_EXPLORING
;
9272 verbose_linfo(env
, t
, "%d: ", t
);
9273 verbose_linfo(env
, w
, "%d: ", w
);
9274 verbose(env
, "back-edge from insn %d to %d\n", t
, w
);
9276 } else if (insn_state
[w
] == EXPLORED
) {
9277 /* forward- or cross-edge */
9278 insn_state
[t
] = DISCOVERED
| e
;
9280 verbose(env
, "insn state internal bug\n");
9283 return DONE_EXPLORING
;
9286 static int visit_func_call_insn(int t
, int insn_cnt
,
9287 struct bpf_insn
*insns
,
9288 struct bpf_verifier_env
*env
,
9293 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
, false);
9297 if (t
+ 1 < insn_cnt
)
9298 init_explored_state(env
, t
+ 1);
9300 init_explored_state(env
, t
);
9301 ret
= push_insn(t
, t
+ insns
[t
].imm
+ 1, BRANCH
,
9307 /* Visits the instruction at index t and returns one of the following:
9308 * < 0 - an error occurred
9309 * DONE_EXPLORING - the instruction was fully explored
9310 * KEEP_EXPLORING - there is still work to be done before it is fully explored
9312 static int visit_insn(int t
, int insn_cnt
, struct bpf_verifier_env
*env
)
9314 struct bpf_insn
*insns
= env
->prog
->insnsi
;
9317 if (bpf_pseudo_func(insns
+ t
))
9318 return visit_func_call_insn(t
, insn_cnt
, insns
, env
, true);
9320 /* All non-branch instructions have a single fall-through edge. */
9321 if (BPF_CLASS(insns
[t
].code
) != BPF_JMP
&&
9322 BPF_CLASS(insns
[t
].code
) != BPF_JMP32
)
9323 return push_insn(t
, t
+ 1, FALLTHROUGH
, env
, false);
9325 switch (BPF_OP(insns
[t
].code
)) {
9327 return DONE_EXPLORING
;
9330 return visit_func_call_insn(t
, insn_cnt
, insns
, env
,
9331 insns
[t
].src_reg
== BPF_PSEUDO_CALL
);
9334 if (BPF_SRC(insns
[t
].code
) != BPF_K
)
9337 /* unconditional jump with single edge */
9338 ret
= push_insn(t
, t
+ insns
[t
].off
+ 1, FALLTHROUGH
, env
,
9343 /* unconditional jmp is not a good pruning point,
9344 * but it's marked, since backtracking needs
9345 * to record jmp history in is_state_visited().
9347 init_explored_state(env
, t
+ insns
[t
].off
+ 1);
9348 /* tell verifier to check for equivalent states
9349 * after every call and jump
9351 if (t
+ 1 < insn_cnt
)
9352 init_explored_state(env
, t
+ 1);
9357 /* conditional jump with two edges */
9358 init_explored_state(env
, t
);
9359 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
, true);
9363 return push_insn(t
, t
+ insns
[t
].off
+ 1, BRANCH
, env
, true);
9367 /* non-recursive depth-first-search to detect loops in BPF program
9368 * loop == back-edge in directed graph
9370 static int check_cfg(struct bpf_verifier_env
*env
)
9372 int insn_cnt
= env
->prog
->len
;
9373 int *insn_stack
, *insn_state
;
9377 insn_state
= env
->cfg
.insn_state
= kvcalloc(insn_cnt
, sizeof(int), GFP_KERNEL
);
9381 insn_stack
= env
->cfg
.insn_stack
= kvcalloc(insn_cnt
, sizeof(int), GFP_KERNEL
);
9387 insn_state
[0] = DISCOVERED
; /* mark 1st insn as discovered */
9388 insn_stack
[0] = 0; /* 0 is the first instruction */
9389 env
->cfg
.cur_stack
= 1;
9391 while (env
->cfg
.cur_stack
> 0) {
9392 int t
= insn_stack
[env
->cfg
.cur_stack
- 1];
9394 ret
= visit_insn(t
, insn_cnt
, env
);
9396 case DONE_EXPLORING
:
9397 insn_state
[t
] = EXPLORED
;
9398 env
->cfg
.cur_stack
--;
9400 case KEEP_EXPLORING
:
9404 verbose(env
, "visit_insn internal bug\n");
9411 if (env
->cfg
.cur_stack
< 0) {
9412 verbose(env
, "pop stack internal bug\n");
9417 for (i
= 0; i
< insn_cnt
; i
++) {
9418 if (insn_state
[i
] != EXPLORED
) {
9419 verbose(env
, "unreachable insn %d\n", i
);
9424 ret
= 0; /* cfg looks good */
9429 env
->cfg
.insn_state
= env
->cfg
.insn_stack
= NULL
;
9433 static int check_abnormal_return(struct bpf_verifier_env
*env
)
9437 for (i
= 1; i
< env
->subprog_cnt
; i
++) {
9438 if (env
->subprog_info
[i
].has_ld_abs
) {
9439 verbose(env
, "LD_ABS is not allowed in subprogs without BTF\n");
9442 if (env
->subprog_info
[i
].has_tail_call
) {
9443 verbose(env
, "tail_call is not allowed in subprogs without BTF\n");
9450 /* The minimum supported BTF func info size */
9451 #define MIN_BPF_FUNCINFO_SIZE 8
9452 #define MAX_FUNCINFO_REC_SIZE 252
9454 static int check_btf_func(struct bpf_verifier_env
*env
,
9455 const union bpf_attr
*attr
,
9456 union bpf_attr __user
*uattr
)
9458 const struct btf_type
*type
, *func_proto
, *ret_type
;
9459 u32 i
, nfuncs
, urec_size
, min_size
;
9460 u32 krec_size
= sizeof(struct bpf_func_info
);
9461 struct bpf_func_info
*krecord
;
9462 struct bpf_func_info_aux
*info_aux
= NULL
;
9463 struct bpf_prog
*prog
;
9464 const struct btf
*btf
;
9465 void __user
*urecord
;
9466 u32 prev_offset
= 0;
9470 nfuncs
= attr
->func_info_cnt
;
9472 if (check_abnormal_return(env
))
9477 if (nfuncs
!= env
->subprog_cnt
) {
9478 verbose(env
, "number of funcs in func_info doesn't match number of subprogs\n");
9482 urec_size
= attr
->func_info_rec_size
;
9483 if (urec_size
< MIN_BPF_FUNCINFO_SIZE
||
9484 urec_size
> MAX_FUNCINFO_REC_SIZE
||
9485 urec_size
% sizeof(u32
)) {
9486 verbose(env
, "invalid func info rec size %u\n", urec_size
);
9491 btf
= prog
->aux
->btf
;
9493 urecord
= u64_to_user_ptr(attr
->func_info
);
9494 min_size
= min_t(u32
, krec_size
, urec_size
);
9496 krecord
= kvcalloc(nfuncs
, krec_size
, GFP_KERNEL
| __GFP_NOWARN
);
9499 info_aux
= kcalloc(nfuncs
, sizeof(*info_aux
), GFP_KERNEL
| __GFP_NOWARN
);
9503 for (i
= 0; i
< nfuncs
; i
++) {
9504 ret
= bpf_check_uarg_tail_zero(urecord
, krec_size
, urec_size
);
9506 if (ret
== -E2BIG
) {
9507 verbose(env
, "nonzero tailing record in func info");
9508 /* set the size kernel expects so loader can zero
9509 * out the rest of the record.
9511 if (put_user(min_size
, &uattr
->func_info_rec_size
))
9517 if (copy_from_user(&krecord
[i
], urecord
, min_size
)) {
9522 /* check insn_off */
9525 if (krecord
[i
].insn_off
) {
9527 "nonzero insn_off %u for the first func info record",
9528 krecord
[i
].insn_off
);
9531 } else if (krecord
[i
].insn_off
<= prev_offset
) {
9533 "same or smaller insn offset (%u) than previous func info record (%u)",
9534 krecord
[i
].insn_off
, prev_offset
);
9538 if (env
->subprog_info
[i
].start
!= krecord
[i
].insn_off
) {
9539 verbose(env
, "func_info BTF section doesn't match subprog layout in BPF program\n");
9544 type
= btf_type_by_id(btf
, krecord
[i
].type_id
);
9545 if (!type
|| !btf_type_is_func(type
)) {
9546 verbose(env
, "invalid type id %d in func info",
9547 krecord
[i
].type_id
);
9550 info_aux
[i
].linkage
= BTF_INFO_VLEN(type
->info
);
9552 func_proto
= btf_type_by_id(btf
, type
->type
);
9553 if (unlikely(!func_proto
|| !btf_type_is_func_proto(func_proto
)))
9554 /* btf_func_check() already verified it during BTF load */
9556 ret_type
= btf_type_skip_modifiers(btf
, func_proto
->type
, NULL
);
9558 btf_type_is_small_int(ret_type
) || btf_type_is_enum(ret_type
);
9559 if (i
&& !scalar_return
&& env
->subprog_info
[i
].has_ld_abs
) {
9560 verbose(env
, "LD_ABS is only allowed in functions that return 'int'.\n");
9563 if (i
&& !scalar_return
&& env
->subprog_info
[i
].has_tail_call
) {
9564 verbose(env
, "tail_call is only allowed in functions that return 'int'.\n");
9568 prev_offset
= krecord
[i
].insn_off
;
9569 urecord
+= urec_size
;
9572 prog
->aux
->func_info
= krecord
;
9573 prog
->aux
->func_info_cnt
= nfuncs
;
9574 prog
->aux
->func_info_aux
= info_aux
;
9583 static void adjust_btf_func(struct bpf_verifier_env
*env
)
9585 struct bpf_prog_aux
*aux
= env
->prog
->aux
;
9588 if (!aux
->func_info
)
9591 for (i
= 0; i
< env
->subprog_cnt
; i
++)
9592 aux
->func_info
[i
].insn_off
= env
->subprog_info
[i
].start
;
9595 #define MIN_BPF_LINEINFO_SIZE (offsetof(struct bpf_line_info, line_col) + \
9596 sizeof(((struct bpf_line_info *)(0))->line_col))
9597 #define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE
9599 static int check_btf_line(struct bpf_verifier_env
*env
,
9600 const union bpf_attr
*attr
,
9601 union bpf_attr __user
*uattr
)
9603 u32 i
, s
, nr_linfo
, ncopy
, expected_size
, rec_size
, prev_offset
= 0;
9604 struct bpf_subprog_info
*sub
;
9605 struct bpf_line_info
*linfo
;
9606 struct bpf_prog
*prog
;
9607 const struct btf
*btf
;
9608 void __user
*ulinfo
;
9611 nr_linfo
= attr
->line_info_cnt
;
9615 rec_size
= attr
->line_info_rec_size
;
9616 if (rec_size
< MIN_BPF_LINEINFO_SIZE
||
9617 rec_size
> MAX_LINEINFO_REC_SIZE
||
9618 rec_size
& (sizeof(u32
) - 1))
9621 /* Need to zero it in case the userspace may
9622 * pass in a smaller bpf_line_info object.
9624 linfo
= kvcalloc(nr_linfo
, sizeof(struct bpf_line_info
),
9625 GFP_KERNEL
| __GFP_NOWARN
);
9630 btf
= prog
->aux
->btf
;
9633 sub
= env
->subprog_info
;
9634 ulinfo
= u64_to_user_ptr(attr
->line_info
);
9635 expected_size
= sizeof(struct bpf_line_info
);
9636 ncopy
= min_t(u32
, expected_size
, rec_size
);
9637 for (i
= 0; i
< nr_linfo
; i
++) {
9638 err
= bpf_check_uarg_tail_zero(ulinfo
, expected_size
, rec_size
);
9640 if (err
== -E2BIG
) {
9641 verbose(env
, "nonzero tailing record in line_info");
9642 if (put_user(expected_size
,
9643 &uattr
->line_info_rec_size
))
9649 if (copy_from_user(&linfo
[i
], ulinfo
, ncopy
)) {
9655 * Check insn_off to ensure
9656 * 1) strictly increasing AND
9657 * 2) bounded by prog->len
9659 * The linfo[0].insn_off == 0 check logically falls into
9660 * the later "missing bpf_line_info for func..." case
9661 * because the first linfo[0].insn_off must be the
9662 * first sub also and the first sub must have
9663 * subprog_info[0].start == 0.
9665 if ((i
&& linfo
[i
].insn_off
<= prev_offset
) ||
9666 linfo
[i
].insn_off
>= prog
->len
) {
9667 verbose(env
, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
9668 i
, linfo
[i
].insn_off
, prev_offset
,
9674 if (!prog
->insnsi
[linfo
[i
].insn_off
].code
) {
9676 "Invalid insn code at line_info[%u].insn_off\n",
9682 if (!btf_name_by_offset(btf
, linfo
[i
].line_off
) ||
9683 !btf_name_by_offset(btf
, linfo
[i
].file_name_off
)) {
9684 verbose(env
, "Invalid line_info[%u].line_off or .file_name_off\n", i
);
9689 if (s
!= env
->subprog_cnt
) {
9690 if (linfo
[i
].insn_off
== sub
[s
].start
) {
9691 sub
[s
].linfo_idx
= i
;
9693 } else if (sub
[s
].start
< linfo
[i
].insn_off
) {
9694 verbose(env
, "missing bpf_line_info for func#%u\n", s
);
9700 prev_offset
= linfo
[i
].insn_off
;
9704 if (s
!= env
->subprog_cnt
) {
9705 verbose(env
, "missing bpf_line_info for %u funcs starting from func#%u\n",
9706 env
->subprog_cnt
- s
, s
);
9711 prog
->aux
->linfo
= linfo
;
9712 prog
->aux
->nr_linfo
= nr_linfo
;
9721 static int check_btf_info(struct bpf_verifier_env
*env
,
9722 const union bpf_attr
*attr
,
9723 union bpf_attr __user
*uattr
)
9728 if (!attr
->func_info_cnt
&& !attr
->line_info_cnt
) {
9729 if (check_abnormal_return(env
))
9734 btf
= btf_get_by_fd(attr
->prog_btf_fd
);
9736 return PTR_ERR(btf
);
9737 if (btf_is_kernel(btf
)) {
9741 env
->prog
->aux
->btf
= btf
;
9743 err
= check_btf_func(env
, attr
, uattr
);
9747 err
= check_btf_line(env
, attr
, uattr
);
9754 /* check %cur's range satisfies %old's */
9755 static bool range_within(struct bpf_reg_state
*old
,
9756 struct bpf_reg_state
*cur
)
9758 return old
->umin_value
<= cur
->umin_value
&&
9759 old
->umax_value
>= cur
->umax_value
&&
9760 old
->smin_value
<= cur
->smin_value
&&
9761 old
->smax_value
>= cur
->smax_value
&&
9762 old
->u32_min_value
<= cur
->u32_min_value
&&
9763 old
->u32_max_value
>= cur
->u32_max_value
&&
9764 old
->s32_min_value
<= cur
->s32_min_value
&&
9765 old
->s32_max_value
>= cur
->s32_max_value
;
9768 /* Maximum number of register states that can exist at once */
9769 #define ID_MAP_SIZE (MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE)
9775 /* If in the old state two registers had the same id, then they need to have
9776 * the same id in the new state as well. But that id could be different from
9777 * the old state, so we need to track the mapping from old to new ids.
9778 * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent
9779 * regs with old id 5 must also have new id 9 for the new state to be safe. But
9780 * regs with a different old id could still have new id 9, we don't care about
9782 * So we look through our idmap to see if this old id has been seen before. If
9783 * so, we require the new id to match; otherwise, we add the id pair to the map.
9785 static bool check_ids(u32 old_id
, u32 cur_id
, struct idpair
*idmap
)
9789 for (i
= 0; i
< ID_MAP_SIZE
; i
++) {
9790 if (!idmap
[i
].old
) {
9791 /* Reached an empty slot; haven't seen this id before */
9792 idmap
[i
].old
= old_id
;
9793 idmap
[i
].cur
= cur_id
;
9796 if (idmap
[i
].old
== old_id
)
9797 return idmap
[i
].cur
== cur_id
;
9799 /* We ran out of idmap slots, which should be impossible */
9804 static void clean_func_state(struct bpf_verifier_env
*env
,
9805 struct bpf_func_state
*st
)
9807 enum bpf_reg_liveness live
;
9810 for (i
= 0; i
< BPF_REG_FP
; i
++) {
9811 live
= st
->regs
[i
].live
;
9812 /* liveness must not touch this register anymore */
9813 st
->regs
[i
].live
|= REG_LIVE_DONE
;
9814 if (!(live
& REG_LIVE_READ
))
9815 /* since the register is unused, clear its state
9816 * to make further comparison simpler
9818 __mark_reg_not_init(env
, &st
->regs
[i
]);
9821 for (i
= 0; i
< st
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
9822 live
= st
->stack
[i
].spilled_ptr
.live
;
9823 /* liveness must not touch this stack slot anymore */
9824 st
->stack
[i
].spilled_ptr
.live
|= REG_LIVE_DONE
;
9825 if (!(live
& REG_LIVE_READ
)) {
9826 __mark_reg_not_init(env
, &st
->stack
[i
].spilled_ptr
);
9827 for (j
= 0; j
< BPF_REG_SIZE
; j
++)
9828 st
->stack
[i
].slot_type
[j
] = STACK_INVALID
;
9833 static void clean_verifier_state(struct bpf_verifier_env
*env
,
9834 struct bpf_verifier_state
*st
)
9838 if (st
->frame
[0]->regs
[0].live
& REG_LIVE_DONE
)
9839 /* all regs in this state in all frames were already marked */
9842 for (i
= 0; i
<= st
->curframe
; i
++)
9843 clean_func_state(env
, st
->frame
[i
]);
9846 /* the parentage chains form a tree.
9847 * the verifier states are added to state lists at given insn and
9848 * pushed into state stack for future exploration.
9849 * when the verifier reaches bpf_exit insn some of the verifer states
9850 * stored in the state lists have their final liveness state already,
9851 * but a lot of states will get revised from liveness point of view when
9852 * the verifier explores other branches.
9855 * 2: if r1 == 100 goto pc+1
9858 * when the verifier reaches exit insn the register r0 in the state list of
9859 * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
9860 * of insn 2 and goes exploring further. At the insn 4 it will walk the
9861 * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
9863 * Since the verifier pushes the branch states as it sees them while exploring
9864 * the program the condition of walking the branch instruction for the second
9865 * time means that all states below this branch were already explored and
9866 * their final liveness markes are already propagated.
9867 * Hence when the verifier completes the search of state list in is_state_visited()
9868 * we can call this clean_live_states() function to mark all liveness states
9869 * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
9871 * This function also clears the registers and stack for states that !READ
9872 * to simplify state merging.
9874 * Important note here that walking the same branch instruction in the callee
9875 * doesn't meant that the states are DONE. The verifier has to compare
9878 static void clean_live_states(struct bpf_verifier_env
*env
, int insn
,
9879 struct bpf_verifier_state
*cur
)
9881 struct bpf_verifier_state_list
*sl
;
9884 sl
= *explored_state(env
, insn
);
9886 if (sl
->state
.branches
)
9888 if (sl
->state
.insn_idx
!= insn
||
9889 sl
->state
.curframe
!= cur
->curframe
)
9891 for (i
= 0; i
<= cur
->curframe
; i
++)
9892 if (sl
->state
.frame
[i
]->callsite
!= cur
->frame
[i
]->callsite
)
9894 clean_verifier_state(env
, &sl
->state
);
9900 /* Returns true if (rold safe implies rcur safe) */
9901 static bool regsafe(struct bpf_reg_state
*rold
, struct bpf_reg_state
*rcur
,
9902 struct idpair
*idmap
)
9906 if (!(rold
->live
& REG_LIVE_READ
))
9907 /* explored state didn't use this */
9910 equal
= memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, parent
)) == 0;
9912 if (rold
->type
== PTR_TO_STACK
)
9913 /* two stack pointers are equal only if they're pointing to
9914 * the same stack frame, since fp-8 in foo != fp-8 in bar
9916 return equal
&& rold
->frameno
== rcur
->frameno
;
9921 if (rold
->type
== NOT_INIT
)
9922 /* explored state can't have used this */
9924 if (rcur
->type
== NOT_INIT
)
9926 switch (rold
->type
) {
9928 if (rcur
->type
== SCALAR_VALUE
) {
9929 if (!rold
->precise
&& !rcur
->precise
)
9931 /* new val must satisfy old val knowledge */
9932 return range_within(rold
, rcur
) &&
9933 tnum_in(rold
->var_off
, rcur
->var_off
);
9935 /* We're trying to use a pointer in place of a scalar.
9936 * Even if the scalar was unbounded, this could lead to
9937 * pointer leaks because scalars are allowed to leak
9938 * while pointers are not. We could make this safe in
9939 * special cases if root is calling us, but it's
9940 * probably not worth the hassle.
9944 case PTR_TO_MAP_KEY
:
9945 case PTR_TO_MAP_VALUE
:
9946 /* If the new min/max/var_off satisfy the old ones and
9947 * everything else matches, we are OK.
9948 * 'id' is not compared, since it's only used for maps with
9949 * bpf_spin_lock inside map element and in such cases if
9950 * the rest of the prog is valid for one map element then
9951 * it's valid for all map elements regardless of the key
9952 * used in bpf_map_lookup()
9954 return memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, id
)) == 0 &&
9955 range_within(rold
, rcur
) &&
9956 tnum_in(rold
->var_off
, rcur
->var_off
);
9957 case PTR_TO_MAP_VALUE_OR_NULL
:
9958 /* a PTR_TO_MAP_VALUE could be safe to use as a
9959 * PTR_TO_MAP_VALUE_OR_NULL into the same map.
9960 * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL-
9961 * checked, doing so could have affected others with the same
9962 * id, and we can't check for that because we lost the id when
9963 * we converted to a PTR_TO_MAP_VALUE.
9965 if (rcur
->type
!= PTR_TO_MAP_VALUE_OR_NULL
)
9967 if (memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, id
)))
9969 /* Check our ids match any regs they're supposed to */
9970 return check_ids(rold
->id
, rcur
->id
, idmap
);
9971 case PTR_TO_PACKET_META
:
9973 if (rcur
->type
!= rold
->type
)
9975 /* We must have at least as much range as the old ptr
9976 * did, so that any accesses which were safe before are
9977 * still safe. This is true even if old range < old off,
9978 * since someone could have accessed through (ptr - k), or
9979 * even done ptr -= k in a register, to get a safe access.
9981 if (rold
->range
> rcur
->range
)
9983 /* If the offsets don't match, we can't trust our alignment;
9984 * nor can we be sure that we won't fall out of range.
9986 if (rold
->off
!= rcur
->off
)
9988 /* id relations must be preserved */
9989 if (rold
->id
&& !check_ids(rold
->id
, rcur
->id
, idmap
))
9991 /* new val must satisfy old val knowledge */
9992 return range_within(rold
, rcur
) &&
9993 tnum_in(rold
->var_off
, rcur
->var_off
);
9995 case CONST_PTR_TO_MAP
:
9996 case PTR_TO_PACKET_END
:
9997 case PTR_TO_FLOW_KEYS
:
9999 case PTR_TO_SOCKET_OR_NULL
:
10000 case PTR_TO_SOCK_COMMON
:
10001 case PTR_TO_SOCK_COMMON_OR_NULL
:
10002 case PTR_TO_TCP_SOCK
:
10003 case PTR_TO_TCP_SOCK_OR_NULL
:
10004 case PTR_TO_XDP_SOCK
:
10005 /* Only valid matches are exact, which memcmp() above
10006 * would have accepted
10009 /* Don't know what's going on, just say it's not safe */
10013 /* Shouldn't get here; if we do, say it's not safe */
10018 static bool stacksafe(struct bpf_func_state
*old
,
10019 struct bpf_func_state
*cur
,
10020 struct idpair
*idmap
)
10024 /* walk slots of the explored stack and ignore any additional
10025 * slots in the current stack, since explored(safe) state
10028 for (i
= 0; i
< old
->allocated_stack
; i
++) {
10029 spi
= i
/ BPF_REG_SIZE
;
10031 if (!(old
->stack
[spi
].spilled_ptr
.live
& REG_LIVE_READ
)) {
10032 i
+= BPF_REG_SIZE
- 1;
10033 /* explored state didn't use this */
10037 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_INVALID
)
10040 /* explored stack has more populated slots than current stack
10041 * and these slots were used
10043 if (i
>= cur
->allocated_stack
)
10046 /* if old state was safe with misc data in the stack
10047 * it will be safe with zero-initialized stack.
10048 * The opposite is not true
10050 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_MISC
&&
10051 cur
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_ZERO
)
10053 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] !=
10054 cur
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
])
10055 /* Ex: old explored (safe) state has STACK_SPILL in
10056 * this stack slot, but current has STACK_MISC ->
10057 * this verifier states are not equivalent,
10058 * return false to continue verification of this path
10061 if (i
% BPF_REG_SIZE
)
10063 if (old
->stack
[spi
].slot_type
[0] != STACK_SPILL
)
10065 if (!regsafe(&old
->stack
[spi
].spilled_ptr
,
10066 &cur
->stack
[spi
].spilled_ptr
,
10068 /* when explored and current stack slot are both storing
10069 * spilled registers, check that stored pointers types
10070 * are the same as well.
10071 * Ex: explored safe path could have stored
10072 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
10073 * but current path has stored:
10074 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
10075 * such verifier states are not equivalent.
10076 * return false to continue verification of this path
10083 static bool refsafe(struct bpf_func_state
*old
, struct bpf_func_state
*cur
)
10085 if (old
->acquired_refs
!= cur
->acquired_refs
)
10087 return !memcmp(old
->refs
, cur
->refs
,
10088 sizeof(*old
->refs
) * old
->acquired_refs
);
10091 /* compare two verifier states
10093 * all states stored in state_list are known to be valid, since
10094 * verifier reached 'bpf_exit' instruction through them
10096 * this function is called when verifier exploring different branches of
10097 * execution popped from the state stack. If it sees an old state that has
10098 * more strict register state and more strict stack state then this execution
10099 * branch doesn't need to be explored further, since verifier already
10100 * concluded that more strict state leads to valid finish.
10102 * Therefore two states are equivalent if register state is more conservative
10103 * and explored stack state is more conservative than the current one.
10106 * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
10107 * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
10109 * In other words if current stack state (one being explored) has more
10110 * valid slots than old one that already passed validation, it means
10111 * the verifier can stop exploring and conclude that current state is valid too
10113 * Similarly with registers. If explored state has register type as invalid
10114 * whereas register type in current state is meaningful, it means that
10115 * the current state will reach 'bpf_exit' instruction safely
10117 static bool func_states_equal(struct bpf_func_state
*old
,
10118 struct bpf_func_state
*cur
)
10120 struct idpair
*idmap
;
10124 idmap
= kcalloc(ID_MAP_SIZE
, sizeof(struct idpair
), GFP_KERNEL
);
10125 /* If we failed to allocate the idmap, just say it's not safe */
10129 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
10130 if (!regsafe(&old
->regs
[i
], &cur
->regs
[i
], idmap
))
10134 if (!stacksafe(old
, cur
, idmap
))
10137 if (!refsafe(old
, cur
))
10145 static bool states_equal(struct bpf_verifier_env
*env
,
10146 struct bpf_verifier_state
*old
,
10147 struct bpf_verifier_state
*cur
)
10151 if (old
->curframe
!= cur
->curframe
)
10154 /* Verification state from speculative execution simulation
10155 * must never prune a non-speculative execution one.
10157 if (old
->speculative
&& !cur
->speculative
)
10160 if (old
->active_spin_lock
!= cur
->active_spin_lock
)
10163 /* for states to be equal callsites have to be the same
10164 * and all frame states need to be equivalent
10166 for (i
= 0; i
<= old
->curframe
; i
++) {
10167 if (old
->frame
[i
]->callsite
!= cur
->frame
[i
]->callsite
)
10169 if (!func_states_equal(old
->frame
[i
], cur
->frame
[i
]))
10175 /* Return 0 if no propagation happened. Return negative error code if error
10176 * happened. Otherwise, return the propagated bit.
10178 static int propagate_liveness_reg(struct bpf_verifier_env
*env
,
10179 struct bpf_reg_state
*reg
,
10180 struct bpf_reg_state
*parent_reg
)
10182 u8 parent_flag
= parent_reg
->live
& REG_LIVE_READ
;
10183 u8 flag
= reg
->live
& REG_LIVE_READ
;
10186 /* When comes here, read flags of PARENT_REG or REG could be any of
10187 * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
10188 * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
10190 if (parent_flag
== REG_LIVE_READ64
||
10191 /* Or if there is no read flag from REG. */
10193 /* Or if the read flag from REG is the same as PARENT_REG. */
10194 parent_flag
== flag
)
10197 err
= mark_reg_read(env
, reg
, parent_reg
, flag
);
10204 /* A write screens off any subsequent reads; but write marks come from the
10205 * straight-line code between a state and its parent. When we arrive at an
10206 * equivalent state (jump target or such) we didn't arrive by the straight-line
10207 * code, so read marks in the state must propagate to the parent regardless
10208 * of the state's write marks. That's what 'parent == state->parent' comparison
10209 * in mark_reg_read() is for.
10211 static int propagate_liveness(struct bpf_verifier_env
*env
,
10212 const struct bpf_verifier_state
*vstate
,
10213 struct bpf_verifier_state
*vparent
)
10215 struct bpf_reg_state
*state_reg
, *parent_reg
;
10216 struct bpf_func_state
*state
, *parent
;
10217 int i
, frame
, err
= 0;
10219 if (vparent
->curframe
!= vstate
->curframe
) {
10220 WARN(1, "propagate_live: parent frame %d current frame %d\n",
10221 vparent
->curframe
, vstate
->curframe
);
10224 /* Propagate read liveness of registers... */
10225 BUILD_BUG_ON(BPF_REG_FP
+ 1 != MAX_BPF_REG
);
10226 for (frame
= 0; frame
<= vstate
->curframe
; frame
++) {
10227 parent
= vparent
->frame
[frame
];
10228 state
= vstate
->frame
[frame
];
10229 parent_reg
= parent
->regs
;
10230 state_reg
= state
->regs
;
10231 /* We don't need to worry about FP liveness, it's read-only */
10232 for (i
= frame
< vstate
->curframe
? BPF_REG_6
: 0; i
< BPF_REG_FP
; i
++) {
10233 err
= propagate_liveness_reg(env
, &state_reg
[i
],
10237 if (err
== REG_LIVE_READ64
)
10238 mark_insn_zext(env
, &parent_reg
[i
]);
10241 /* Propagate stack slots. */
10242 for (i
= 0; i
< state
->allocated_stack
/ BPF_REG_SIZE
&&
10243 i
< parent
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
10244 parent_reg
= &parent
->stack
[i
].spilled_ptr
;
10245 state_reg
= &state
->stack
[i
].spilled_ptr
;
10246 err
= propagate_liveness_reg(env
, state_reg
,
10255 /* find precise scalars in the previous equivalent state and
10256 * propagate them into the current state
10258 static int propagate_precision(struct bpf_verifier_env
*env
,
10259 const struct bpf_verifier_state
*old
)
10261 struct bpf_reg_state
*state_reg
;
10262 struct bpf_func_state
*state
;
10265 state
= old
->frame
[old
->curframe
];
10266 state_reg
= state
->regs
;
10267 for (i
= 0; i
< BPF_REG_FP
; i
++, state_reg
++) {
10268 if (state_reg
->type
!= SCALAR_VALUE
||
10269 !state_reg
->precise
)
10271 if (env
->log
.level
& BPF_LOG_LEVEL2
)
10272 verbose(env
, "propagating r%d\n", i
);
10273 err
= mark_chain_precision(env
, i
);
10278 for (i
= 0; i
< state
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
10279 if (state
->stack
[i
].slot_type
[0] != STACK_SPILL
)
10281 state_reg
= &state
->stack
[i
].spilled_ptr
;
10282 if (state_reg
->type
!= SCALAR_VALUE
||
10283 !state_reg
->precise
)
10285 if (env
->log
.level
& BPF_LOG_LEVEL2
)
10286 verbose(env
, "propagating fp%d\n",
10287 (-i
- 1) * BPF_REG_SIZE
);
10288 err
= mark_chain_precision_stack(env
, i
);
10295 static bool states_maybe_looping(struct bpf_verifier_state
*old
,
10296 struct bpf_verifier_state
*cur
)
10298 struct bpf_func_state
*fold
, *fcur
;
10299 int i
, fr
= cur
->curframe
;
10301 if (old
->curframe
!= fr
)
10304 fold
= old
->frame
[fr
];
10305 fcur
= cur
->frame
[fr
];
10306 for (i
= 0; i
< MAX_BPF_REG
; i
++)
10307 if (memcmp(&fold
->regs
[i
], &fcur
->regs
[i
],
10308 offsetof(struct bpf_reg_state
, parent
)))
10314 static int is_state_visited(struct bpf_verifier_env
*env
, int insn_idx
)
10316 struct bpf_verifier_state_list
*new_sl
;
10317 struct bpf_verifier_state_list
*sl
, **pprev
;
10318 struct bpf_verifier_state
*cur
= env
->cur_state
, *new;
10319 int i
, j
, err
, states_cnt
= 0;
10320 bool add_new_state
= env
->test_state_freq
? true : false;
10322 cur
->last_insn_idx
= env
->prev_insn_idx
;
10323 if (!env
->insn_aux_data
[insn_idx
].prune_point
)
10324 /* this 'insn_idx' instruction wasn't marked, so we will not
10325 * be doing state search here
10329 /* bpf progs typically have pruning point every 4 instructions
10330 * http://vger.kernel.org/bpfconf2019.html#session-1
10331 * Do not add new state for future pruning if the verifier hasn't seen
10332 * at least 2 jumps and at least 8 instructions.
10333 * This heuristics helps decrease 'total_states' and 'peak_states' metric.
10334 * In tests that amounts to up to 50% reduction into total verifier
10335 * memory consumption and 20% verifier time speedup.
10337 if (env
->jmps_processed
- env
->prev_jmps_processed
>= 2 &&
10338 env
->insn_processed
- env
->prev_insn_processed
>= 8)
10339 add_new_state
= true;
10341 pprev
= explored_state(env
, insn_idx
);
10344 clean_live_states(env
, insn_idx
, cur
);
10348 if (sl
->state
.insn_idx
!= insn_idx
)
10350 if (sl
->state
.branches
) {
10351 if (states_maybe_looping(&sl
->state
, cur
) &&
10352 states_equal(env
, &sl
->state
, cur
)) {
10353 verbose_linfo(env
, insn_idx
, "; ");
10354 verbose(env
, "infinite loop detected at insn %d\n", insn_idx
);
10357 /* if the verifier is processing a loop, avoid adding new state
10358 * too often, since different loop iterations have distinct
10359 * states and may not help future pruning.
10360 * This threshold shouldn't be too low to make sure that
10361 * a loop with large bound will be rejected quickly.
10362 * The most abusive loop will be:
10364 * if r1 < 1000000 goto pc-2
10365 * 1M insn_procssed limit / 100 == 10k peak states.
10366 * This threshold shouldn't be too high either, since states
10367 * at the end of the loop are likely to be useful in pruning.
10369 if (env
->jmps_processed
- env
->prev_jmps_processed
< 20 &&
10370 env
->insn_processed
- env
->prev_insn_processed
< 100)
10371 add_new_state
= false;
10374 if (states_equal(env
, &sl
->state
, cur
)) {
10376 /* reached equivalent register/stack state,
10377 * prune the search.
10378 * Registers read by the continuation are read by us.
10379 * If we have any write marks in env->cur_state, they
10380 * will prevent corresponding reads in the continuation
10381 * from reaching our parent (an explored_state). Our
10382 * own state will get the read marks recorded, but
10383 * they'll be immediately forgotten as we're pruning
10384 * this state and will pop a new one.
10386 err
= propagate_liveness(env
, &sl
->state
, cur
);
10388 /* if previous state reached the exit with precision and
10389 * current state is equivalent to it (except precsion marks)
10390 * the precision needs to be propagated back in
10391 * the current state.
10393 err
= err
? : push_jmp_history(env
, cur
);
10394 err
= err
? : propagate_precision(env
, &sl
->state
);
10400 /* when new state is not going to be added do not increase miss count.
10401 * Otherwise several loop iterations will remove the state
10402 * recorded earlier. The goal of these heuristics is to have
10403 * states from some iterations of the loop (some in the beginning
10404 * and some at the end) to help pruning.
10408 /* heuristic to determine whether this state is beneficial
10409 * to keep checking from state equivalence point of view.
10410 * Higher numbers increase max_states_per_insn and verification time,
10411 * but do not meaningfully decrease insn_processed.
10413 if (sl
->miss_cnt
> sl
->hit_cnt
* 3 + 3) {
10414 /* the state is unlikely to be useful. Remove it to
10415 * speed up verification
10418 if (sl
->state
.frame
[0]->regs
[0].live
& REG_LIVE_DONE
) {
10419 u32 br
= sl
->state
.branches
;
10422 "BUG live_done but branches_to_explore %d\n",
10424 free_verifier_state(&sl
->state
, false);
10426 env
->peak_states
--;
10428 /* cannot free this state, since parentage chain may
10429 * walk it later. Add it for free_list instead to
10430 * be freed at the end of verification
10432 sl
->next
= env
->free_list
;
10433 env
->free_list
= sl
;
10443 if (env
->max_states_per_insn
< states_cnt
)
10444 env
->max_states_per_insn
= states_cnt
;
10446 if (!env
->bpf_capable
&& states_cnt
> BPF_COMPLEXITY_LIMIT_STATES
)
10447 return push_jmp_history(env
, cur
);
10449 if (!add_new_state
)
10450 return push_jmp_history(env
, cur
);
10452 /* There were no equivalent states, remember the current one.
10453 * Technically the current state is not proven to be safe yet,
10454 * but it will either reach outer most bpf_exit (which means it's safe)
10455 * or it will be rejected. When there are no loops the verifier won't be
10456 * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
10457 * again on the way to bpf_exit.
10458 * When looping the sl->state.branches will be > 0 and this state
10459 * will not be considered for equivalence until branches == 0.
10461 new_sl
= kzalloc(sizeof(struct bpf_verifier_state_list
), GFP_KERNEL
);
10464 env
->total_states
++;
10465 env
->peak_states
++;
10466 env
->prev_jmps_processed
= env
->jmps_processed
;
10467 env
->prev_insn_processed
= env
->insn_processed
;
10469 /* add new state to the head of linked list */
10470 new = &new_sl
->state
;
10471 err
= copy_verifier_state(new, cur
);
10473 free_verifier_state(new, false);
10477 new->insn_idx
= insn_idx
;
10478 WARN_ONCE(new->branches
!= 1,
10479 "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches
, insn_idx
);
10482 cur
->first_insn_idx
= insn_idx
;
10483 clear_jmp_history(cur
);
10484 new_sl
->next
= *explored_state(env
, insn_idx
);
10485 *explored_state(env
, insn_idx
) = new_sl
;
10486 /* connect new state to parentage chain. Current frame needs all
10487 * registers connected. Only r6 - r9 of the callers are alive (pushed
10488 * to the stack implicitly by JITs) so in callers' frames connect just
10489 * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
10490 * the state of the call instruction (with WRITTEN set), and r0 comes
10491 * from callee with its full parentage chain, anyway.
10493 /* clear write marks in current state: the writes we did are not writes
10494 * our child did, so they don't screen off its reads from us.
10495 * (There are no read marks in current state, because reads always mark
10496 * their parent and current state never has children yet. Only
10497 * explored_states can get read marks.)
10499 for (j
= 0; j
<= cur
->curframe
; j
++) {
10500 for (i
= j
< cur
->curframe
? BPF_REG_6
: 0; i
< BPF_REG_FP
; i
++)
10501 cur
->frame
[j
]->regs
[i
].parent
= &new->frame
[j
]->regs
[i
];
10502 for (i
= 0; i
< BPF_REG_FP
; i
++)
10503 cur
->frame
[j
]->regs
[i
].live
= REG_LIVE_NONE
;
10506 /* all stack frames are accessible from callee, clear them all */
10507 for (j
= 0; j
<= cur
->curframe
; j
++) {
10508 struct bpf_func_state
*frame
= cur
->frame
[j
];
10509 struct bpf_func_state
*newframe
= new->frame
[j
];
10511 for (i
= 0; i
< frame
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
10512 frame
->stack
[i
].spilled_ptr
.live
= REG_LIVE_NONE
;
10513 frame
->stack
[i
].spilled_ptr
.parent
=
10514 &newframe
->stack
[i
].spilled_ptr
;
10520 /* Return true if it's OK to have the same insn return a different type. */
10521 static bool reg_type_mismatch_ok(enum bpf_reg_type type
)
10525 case PTR_TO_SOCKET
:
10526 case PTR_TO_SOCKET_OR_NULL
:
10527 case PTR_TO_SOCK_COMMON
:
10528 case PTR_TO_SOCK_COMMON_OR_NULL
:
10529 case PTR_TO_TCP_SOCK
:
10530 case PTR_TO_TCP_SOCK_OR_NULL
:
10531 case PTR_TO_XDP_SOCK
:
10532 case PTR_TO_BTF_ID
:
10533 case PTR_TO_BTF_ID_OR_NULL
:
10540 /* If an instruction was previously used with particular pointer types, then we
10541 * need to be careful to avoid cases such as the below, where it may be ok
10542 * for one branch accessing the pointer, but not ok for the other branch:
10547 * R1 = some_other_valid_ptr;
10550 * R2 = *(u32 *)(R1 + 0);
10552 static bool reg_type_mismatch(enum bpf_reg_type src
, enum bpf_reg_type prev
)
10554 return src
!= prev
&& (!reg_type_mismatch_ok(src
) ||
10555 !reg_type_mismatch_ok(prev
));
10558 static int do_check(struct bpf_verifier_env
*env
)
10560 bool pop_log
= !(env
->log
.level
& BPF_LOG_LEVEL2
);
10561 struct bpf_verifier_state
*state
= env
->cur_state
;
10562 struct bpf_insn
*insns
= env
->prog
->insnsi
;
10563 struct bpf_reg_state
*regs
;
10564 int insn_cnt
= env
->prog
->len
;
10565 bool do_print_state
= false;
10566 int prev_insn_idx
= -1;
10569 struct bpf_insn
*insn
;
10573 env
->prev_insn_idx
= prev_insn_idx
;
10574 if (env
->insn_idx
>= insn_cnt
) {
10575 verbose(env
, "invalid insn idx %d insn_cnt %d\n",
10576 env
->insn_idx
, insn_cnt
);
10580 insn
= &insns
[env
->insn_idx
];
10581 class = BPF_CLASS(insn
->code
);
10583 if (++env
->insn_processed
> BPF_COMPLEXITY_LIMIT_INSNS
) {
10585 "BPF program is too large. Processed %d insn\n",
10586 env
->insn_processed
);
10590 err
= is_state_visited(env
, env
->insn_idx
);
10594 /* found equivalent state, can prune the search */
10595 if (env
->log
.level
& BPF_LOG_LEVEL
) {
10596 if (do_print_state
)
10597 verbose(env
, "\nfrom %d to %d%s: safe\n",
10598 env
->prev_insn_idx
, env
->insn_idx
,
10599 env
->cur_state
->speculative
?
10600 " (speculative execution)" : "");
10602 verbose(env
, "%d: safe\n", env
->insn_idx
);
10604 goto process_bpf_exit
;
10607 if (signal_pending(current
))
10610 if (need_resched())
10613 if (env
->log
.level
& BPF_LOG_LEVEL2
||
10614 (env
->log
.level
& BPF_LOG_LEVEL
&& do_print_state
)) {
10615 if (env
->log
.level
& BPF_LOG_LEVEL2
)
10616 verbose(env
, "%d:", env
->insn_idx
);
10618 verbose(env
, "\nfrom %d to %d%s:",
10619 env
->prev_insn_idx
, env
->insn_idx
,
10620 env
->cur_state
->speculative
?
10621 " (speculative execution)" : "");
10622 print_verifier_state(env
, state
->frame
[state
->curframe
]);
10623 do_print_state
= false;
10626 if (env
->log
.level
& BPF_LOG_LEVEL
) {
10627 const struct bpf_insn_cbs cbs
= {
10628 .cb_call
= disasm_kfunc_name
,
10629 .cb_print
= verbose
,
10630 .private_data
= env
,
10633 verbose_linfo(env
, env
->insn_idx
, "; ");
10634 verbose(env
, "%d: ", env
->insn_idx
);
10635 print_bpf_insn(&cbs
, insn
, env
->allow_ptr_leaks
);
10638 if (bpf_prog_is_dev_bound(env
->prog
->aux
)) {
10639 err
= bpf_prog_offload_verify_insn(env
, env
->insn_idx
,
10640 env
->prev_insn_idx
);
10645 regs
= cur_regs(env
);
10646 sanitize_mark_insn_seen(env
);
10647 prev_insn_idx
= env
->insn_idx
;
10649 if (class == BPF_ALU
|| class == BPF_ALU64
) {
10650 err
= check_alu_op(env
, insn
);
10654 } else if (class == BPF_LDX
) {
10655 enum bpf_reg_type
*prev_src_type
, src_reg_type
;
10657 /* check for reserved fields is already done */
10659 /* check src operand */
10660 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
10664 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
10668 src_reg_type
= regs
[insn
->src_reg
].type
;
10670 /* check that memory (src_reg + off) is readable,
10671 * the state of dst_reg will be updated by this func
10673 err
= check_mem_access(env
, env
->insn_idx
, insn
->src_reg
,
10674 insn
->off
, BPF_SIZE(insn
->code
),
10675 BPF_READ
, insn
->dst_reg
, false);
10679 prev_src_type
= &env
->insn_aux_data
[env
->insn_idx
].ptr_type
;
10681 if (*prev_src_type
== NOT_INIT
) {
10682 /* saw a valid insn
10683 * dst_reg = *(u32 *)(src_reg + off)
10684 * save type to validate intersecting paths
10686 *prev_src_type
= src_reg_type
;
10688 } else if (reg_type_mismatch(src_reg_type
, *prev_src_type
)) {
10689 /* ABuser program is trying to use the same insn
10690 * dst_reg = *(u32*) (src_reg + off)
10691 * with different pointer types:
10692 * src_reg == ctx in one branch and
10693 * src_reg == stack|map in some other branch.
10696 verbose(env
, "same insn cannot be used with different pointers\n");
10700 } else if (class == BPF_STX
) {
10701 enum bpf_reg_type
*prev_dst_type
, dst_reg_type
;
10703 if (BPF_MODE(insn
->code
) == BPF_ATOMIC
) {
10704 err
= check_atomic(env
, env
->insn_idx
, insn
);
10711 if (BPF_MODE(insn
->code
) != BPF_MEM
|| insn
->imm
!= 0) {
10712 verbose(env
, "BPF_STX uses reserved fields\n");
10716 /* check src1 operand */
10717 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
10720 /* check src2 operand */
10721 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
10725 dst_reg_type
= regs
[insn
->dst_reg
].type
;
10727 /* check that memory (dst_reg + off) is writeable */
10728 err
= check_mem_access(env
, env
->insn_idx
, insn
->dst_reg
,
10729 insn
->off
, BPF_SIZE(insn
->code
),
10730 BPF_WRITE
, insn
->src_reg
, false);
10734 prev_dst_type
= &env
->insn_aux_data
[env
->insn_idx
].ptr_type
;
10736 if (*prev_dst_type
== NOT_INIT
) {
10737 *prev_dst_type
= dst_reg_type
;
10738 } else if (reg_type_mismatch(dst_reg_type
, *prev_dst_type
)) {
10739 verbose(env
, "same insn cannot be used with different pointers\n");
10743 } else if (class == BPF_ST
) {
10744 if (BPF_MODE(insn
->code
) != BPF_MEM
||
10745 insn
->src_reg
!= BPF_REG_0
) {
10746 verbose(env
, "BPF_ST uses reserved fields\n");
10749 /* check src operand */
10750 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
10754 if (is_ctx_reg(env
, insn
->dst_reg
)) {
10755 verbose(env
, "BPF_ST stores into R%d %s is not allowed\n",
10757 reg_type_str
[reg_state(env
, insn
->dst_reg
)->type
]);
10761 /* check that memory (dst_reg + off) is writeable */
10762 err
= check_mem_access(env
, env
->insn_idx
, insn
->dst_reg
,
10763 insn
->off
, BPF_SIZE(insn
->code
),
10764 BPF_WRITE
, -1, false);
10768 } else if (class == BPF_JMP
|| class == BPF_JMP32
) {
10769 u8 opcode
= BPF_OP(insn
->code
);
10771 env
->jmps_processed
++;
10772 if (opcode
== BPF_CALL
) {
10773 if (BPF_SRC(insn
->code
) != BPF_K
||
10775 (insn
->src_reg
!= BPF_REG_0
&&
10776 insn
->src_reg
!= BPF_PSEUDO_CALL
&&
10777 insn
->src_reg
!= BPF_PSEUDO_KFUNC_CALL
) ||
10778 insn
->dst_reg
!= BPF_REG_0
||
10779 class == BPF_JMP32
) {
10780 verbose(env
, "BPF_CALL uses reserved fields\n");
10784 if (env
->cur_state
->active_spin_lock
&&
10785 (insn
->src_reg
== BPF_PSEUDO_CALL
||
10786 insn
->imm
!= BPF_FUNC_spin_unlock
)) {
10787 verbose(env
, "function calls are not allowed while holding a lock\n");
10790 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
10791 err
= check_func_call(env
, insn
, &env
->insn_idx
);
10792 else if (insn
->src_reg
== BPF_PSEUDO_KFUNC_CALL
)
10793 err
= check_kfunc_call(env
, insn
);
10795 err
= check_helper_call(env
, insn
, &env
->insn_idx
);
10798 } else if (opcode
== BPF_JA
) {
10799 if (BPF_SRC(insn
->code
) != BPF_K
||
10801 insn
->src_reg
!= BPF_REG_0
||
10802 insn
->dst_reg
!= BPF_REG_0
||
10803 class == BPF_JMP32
) {
10804 verbose(env
, "BPF_JA uses reserved fields\n");
10808 env
->insn_idx
+= insn
->off
+ 1;
10811 } else if (opcode
== BPF_EXIT
) {
10812 if (BPF_SRC(insn
->code
) != BPF_K
||
10814 insn
->src_reg
!= BPF_REG_0
||
10815 insn
->dst_reg
!= BPF_REG_0
||
10816 class == BPF_JMP32
) {
10817 verbose(env
, "BPF_EXIT uses reserved fields\n");
10821 if (env
->cur_state
->active_spin_lock
) {
10822 verbose(env
, "bpf_spin_unlock is missing\n");
10826 if (state
->curframe
) {
10827 /* exit from nested function */
10828 err
= prepare_func_exit(env
, &env
->insn_idx
);
10831 do_print_state
= true;
10835 err
= check_reference_leak(env
);
10839 err
= check_return_code(env
);
10843 update_branch_counts(env
, env
->cur_state
);
10844 err
= pop_stack(env
, &prev_insn_idx
,
10845 &env
->insn_idx
, pop_log
);
10847 if (err
!= -ENOENT
)
10851 do_print_state
= true;
10855 err
= check_cond_jmp_op(env
, insn
, &env
->insn_idx
);
10859 } else if (class == BPF_LD
) {
10860 u8 mode
= BPF_MODE(insn
->code
);
10862 if (mode
== BPF_ABS
|| mode
== BPF_IND
) {
10863 err
= check_ld_abs(env
, insn
);
10867 } else if (mode
== BPF_IMM
) {
10868 err
= check_ld_imm(env
, insn
);
10873 sanitize_mark_insn_seen(env
);
10875 verbose(env
, "invalid BPF_LD mode\n");
10879 verbose(env
, "unknown insn class %d\n", class);
10889 static int find_btf_percpu_datasec(struct btf
*btf
)
10891 const struct btf_type
*t
;
10896 * Both vmlinux and module each have their own ".data..percpu"
10897 * DATASECs in BTF. So for module's case, we need to skip vmlinux BTF
10898 * types to look at only module's own BTF types.
10900 n
= btf_nr_types(btf
);
10901 if (btf_is_module(btf
))
10902 i
= btf_nr_types(btf_vmlinux
);
10906 for(; i
< n
; i
++) {
10907 t
= btf_type_by_id(btf
, i
);
10908 if (BTF_INFO_KIND(t
->info
) != BTF_KIND_DATASEC
)
10911 tname
= btf_name_by_offset(btf
, t
->name_off
);
10912 if (!strcmp(tname
, ".data..percpu"))
10919 /* replace pseudo btf_id with kernel symbol address */
10920 static int check_pseudo_btf_id(struct bpf_verifier_env
*env
,
10921 struct bpf_insn
*insn
,
10922 struct bpf_insn_aux_data
*aux
)
10924 const struct btf_var_secinfo
*vsi
;
10925 const struct btf_type
*datasec
;
10926 struct btf_mod_pair
*btf_mod
;
10927 const struct btf_type
*t
;
10928 const char *sym_name
;
10929 bool percpu
= false;
10930 u32 type
, id
= insn
->imm
;
10934 int i
, btf_fd
, err
;
10936 btf_fd
= insn
[1].imm
;
10938 btf
= btf_get_by_fd(btf_fd
);
10940 verbose(env
, "invalid module BTF object FD specified.\n");
10944 if (!btf_vmlinux
) {
10945 verbose(env
, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
10952 t
= btf_type_by_id(btf
, id
);
10954 verbose(env
, "ldimm64 insn specifies invalid btf_id %d.\n", id
);
10959 if (!btf_type_is_var(t
)) {
10960 verbose(env
, "pseudo btf_id %d in ldimm64 isn't KIND_VAR.\n", id
);
10965 sym_name
= btf_name_by_offset(btf
, t
->name_off
);
10966 addr
= kallsyms_lookup_name(sym_name
);
10968 verbose(env
, "ldimm64 failed to find the address for kernel symbol '%s'.\n",
10974 datasec_id
= find_btf_percpu_datasec(btf
);
10975 if (datasec_id
> 0) {
10976 datasec
= btf_type_by_id(btf
, datasec_id
);
10977 for_each_vsi(i
, datasec
, vsi
) {
10978 if (vsi
->type
== id
) {
10985 insn
[0].imm
= (u32
)addr
;
10986 insn
[1].imm
= addr
>> 32;
10989 t
= btf_type_skip_modifiers(btf
, type
, NULL
);
10991 aux
->btf_var
.reg_type
= PTR_TO_PERCPU_BTF_ID
;
10992 aux
->btf_var
.btf
= btf
;
10993 aux
->btf_var
.btf_id
= type
;
10994 } else if (!btf_type_is_struct(t
)) {
10995 const struct btf_type
*ret
;
10999 /* resolve the type size of ksym. */
11000 ret
= btf_resolve_size(btf
, t
, &tsize
);
11002 tname
= btf_name_by_offset(btf
, t
->name_off
);
11003 verbose(env
, "ldimm64 unable to resolve the size of type '%s': %ld\n",
11004 tname
, PTR_ERR(ret
));
11008 aux
->btf_var
.reg_type
= PTR_TO_MEM
;
11009 aux
->btf_var
.mem_size
= tsize
;
11011 aux
->btf_var
.reg_type
= PTR_TO_BTF_ID
;
11012 aux
->btf_var
.btf
= btf
;
11013 aux
->btf_var
.btf_id
= type
;
11016 /* check whether we recorded this BTF (and maybe module) already */
11017 for (i
= 0; i
< env
->used_btf_cnt
; i
++) {
11018 if (env
->used_btfs
[i
].btf
== btf
) {
11024 if (env
->used_btf_cnt
>= MAX_USED_BTFS
) {
11029 btf_mod
= &env
->used_btfs
[env
->used_btf_cnt
];
11030 btf_mod
->btf
= btf
;
11031 btf_mod
->module
= NULL
;
11033 /* if we reference variables from kernel module, bump its refcount */
11034 if (btf_is_module(btf
)) {
11035 btf_mod
->module
= btf_try_get_module(btf
);
11036 if (!btf_mod
->module
) {
11042 env
->used_btf_cnt
++;
11050 static int check_map_prealloc(struct bpf_map
*map
)
11052 return (map
->map_type
!= BPF_MAP_TYPE_HASH
&&
11053 map
->map_type
!= BPF_MAP_TYPE_PERCPU_HASH
&&
11054 map
->map_type
!= BPF_MAP_TYPE_HASH_OF_MAPS
) ||
11055 !(map
->map_flags
& BPF_F_NO_PREALLOC
);
11058 static bool is_tracing_prog_type(enum bpf_prog_type type
)
11061 case BPF_PROG_TYPE_KPROBE
:
11062 case BPF_PROG_TYPE_TRACEPOINT
:
11063 case BPF_PROG_TYPE_PERF_EVENT
:
11064 case BPF_PROG_TYPE_RAW_TRACEPOINT
:
11071 static bool is_preallocated_map(struct bpf_map
*map
)
11073 if (!check_map_prealloc(map
))
11075 if (map
->inner_map_meta
&& !check_map_prealloc(map
->inner_map_meta
))
11080 static int check_map_prog_compatibility(struct bpf_verifier_env
*env
,
11081 struct bpf_map
*map
,
11082 struct bpf_prog
*prog
)
11085 enum bpf_prog_type prog_type
= resolve_prog_type(prog
);
11087 * Validate that trace type programs use preallocated hash maps.
11089 * For programs attached to PERF events this is mandatory as the
11090 * perf NMI can hit any arbitrary code sequence.
11092 * All other trace types using preallocated hash maps are unsafe as
11093 * well because tracepoint or kprobes can be inside locked regions
11094 * of the memory allocator or at a place where a recursion into the
11095 * memory allocator would see inconsistent state.
11097 * On RT enabled kernels run-time allocation of all trace type
11098 * programs is strictly prohibited due to lock type constraints. On
11099 * !RT kernels it is allowed for backwards compatibility reasons for
11100 * now, but warnings are emitted so developers are made aware of
11101 * the unsafety and can fix their programs before this is enforced.
11103 if (is_tracing_prog_type(prog_type
) && !is_preallocated_map(map
)) {
11104 if (prog_type
== BPF_PROG_TYPE_PERF_EVENT
) {
11105 verbose(env
, "perf_event programs can only use preallocated hash map\n");
11108 if (IS_ENABLED(CONFIG_PREEMPT_RT
)) {
11109 verbose(env
, "trace type programs can only use preallocated hash map\n");
11112 WARN_ONCE(1, "trace type BPF program uses run-time allocation\n");
11113 verbose(env
, "trace type programs with run-time allocated hash maps are unsafe. Switch to preallocated hash maps.\n");
11116 if (map_value_has_spin_lock(map
)) {
11117 if (prog_type
== BPF_PROG_TYPE_SOCKET_FILTER
) {
11118 verbose(env
, "socket filter progs cannot use bpf_spin_lock yet\n");
11122 if (is_tracing_prog_type(prog_type
)) {
11123 verbose(env
, "tracing progs cannot use bpf_spin_lock yet\n");
11127 if (prog
->aux
->sleepable
) {
11128 verbose(env
, "sleepable progs cannot use bpf_spin_lock yet\n");
11133 if ((bpf_prog_is_dev_bound(prog
->aux
) || bpf_map_is_dev_bound(map
)) &&
11134 !bpf_offload_prog_map_match(prog
, map
)) {
11135 verbose(env
, "offload device mismatch between prog and map\n");
11139 if (map
->map_type
== BPF_MAP_TYPE_STRUCT_OPS
) {
11140 verbose(env
, "bpf_struct_ops map cannot be used in prog\n");
11144 if (prog
->aux
->sleepable
)
11145 switch (map
->map_type
) {
11146 case BPF_MAP_TYPE_HASH
:
11147 case BPF_MAP_TYPE_LRU_HASH
:
11148 case BPF_MAP_TYPE_ARRAY
:
11149 case BPF_MAP_TYPE_PERCPU_HASH
:
11150 case BPF_MAP_TYPE_PERCPU_ARRAY
:
11151 case BPF_MAP_TYPE_LRU_PERCPU_HASH
:
11152 case BPF_MAP_TYPE_ARRAY_OF_MAPS
:
11153 case BPF_MAP_TYPE_HASH_OF_MAPS
:
11154 if (!is_preallocated_map(map
)) {
11156 "Sleepable programs can only use preallocated maps\n");
11160 case BPF_MAP_TYPE_RINGBUF
:
11164 "Sleepable programs can only use array, hash, and ringbuf maps\n");
11171 static bool bpf_map_is_cgroup_storage(struct bpf_map
*map
)
11173 return (map
->map_type
== BPF_MAP_TYPE_CGROUP_STORAGE
||
11174 map
->map_type
== BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
);
11177 /* find and rewrite pseudo imm in ld_imm64 instructions:
11179 * 1. if it accesses map FD, replace it with actual map pointer.
11180 * 2. if it accesses btf_id of a VAR, replace it with pointer to the var.
11182 * NOTE: btf_vmlinux is required for converting pseudo btf_id.
11184 static int resolve_pseudo_ldimm64(struct bpf_verifier_env
*env
)
11186 struct bpf_insn
*insn
= env
->prog
->insnsi
;
11187 int insn_cnt
= env
->prog
->len
;
11190 err
= bpf_prog_calc_tag(env
->prog
);
11194 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
11195 if (BPF_CLASS(insn
->code
) == BPF_LDX
&&
11196 (BPF_MODE(insn
->code
) != BPF_MEM
|| insn
->imm
!= 0)) {
11197 verbose(env
, "BPF_LDX uses reserved fields\n");
11201 if (insn
[0].code
== (BPF_LD
| BPF_IMM
| BPF_DW
)) {
11202 struct bpf_insn_aux_data
*aux
;
11203 struct bpf_map
*map
;
11207 if (i
== insn_cnt
- 1 || insn
[1].code
!= 0 ||
11208 insn
[1].dst_reg
!= 0 || insn
[1].src_reg
!= 0 ||
11209 insn
[1].off
!= 0) {
11210 verbose(env
, "invalid bpf_ld_imm64 insn\n");
11214 if (insn
[0].src_reg
== 0)
11215 /* valid generic load 64-bit imm */
11218 if (insn
[0].src_reg
== BPF_PSEUDO_BTF_ID
) {
11219 aux
= &env
->insn_aux_data
[i
];
11220 err
= check_pseudo_btf_id(env
, insn
, aux
);
11226 if (insn
[0].src_reg
== BPF_PSEUDO_FUNC
) {
11227 aux
= &env
->insn_aux_data
[i
];
11228 aux
->ptr_type
= PTR_TO_FUNC
;
11232 /* In final convert_pseudo_ld_imm64() step, this is
11233 * converted into regular 64-bit imm load insn.
11235 if ((insn
[0].src_reg
!= BPF_PSEUDO_MAP_FD
&&
11236 insn
[0].src_reg
!= BPF_PSEUDO_MAP_VALUE
) ||
11237 (insn
[0].src_reg
== BPF_PSEUDO_MAP_FD
&&
11238 insn
[1].imm
!= 0)) {
11240 "unrecognized bpf_ld_imm64 insn\n");
11244 f
= fdget(insn
[0].imm
);
11245 map
= __bpf_map_get(f
);
11247 verbose(env
, "fd %d is not pointing to valid bpf_map\n",
11249 return PTR_ERR(map
);
11252 err
= check_map_prog_compatibility(env
, map
, env
->prog
);
11258 aux
= &env
->insn_aux_data
[i
];
11259 if (insn
->src_reg
== BPF_PSEUDO_MAP_FD
) {
11260 addr
= (unsigned long)map
;
11262 u32 off
= insn
[1].imm
;
11264 if (off
>= BPF_MAX_VAR_OFF
) {
11265 verbose(env
, "direct value offset of %u is not allowed\n", off
);
11270 if (!map
->ops
->map_direct_value_addr
) {
11271 verbose(env
, "no direct value access support for this map type\n");
11276 err
= map
->ops
->map_direct_value_addr(map
, &addr
, off
);
11278 verbose(env
, "invalid access to map value pointer, value_size=%u off=%u\n",
11279 map
->value_size
, off
);
11284 aux
->map_off
= off
;
11288 insn
[0].imm
= (u32
)addr
;
11289 insn
[1].imm
= addr
>> 32;
11291 /* check whether we recorded this map already */
11292 for (j
= 0; j
< env
->used_map_cnt
; j
++) {
11293 if (env
->used_maps
[j
] == map
) {
11294 aux
->map_index
= j
;
11300 if (env
->used_map_cnt
>= MAX_USED_MAPS
) {
11305 /* hold the map. If the program is rejected by verifier,
11306 * the map will be released by release_maps() or it
11307 * will be used by the valid program until it's unloaded
11308 * and all maps are released in free_used_maps()
11312 aux
->map_index
= env
->used_map_cnt
;
11313 env
->used_maps
[env
->used_map_cnt
++] = map
;
11315 if (bpf_map_is_cgroup_storage(map
) &&
11316 bpf_cgroup_storage_assign(env
->prog
->aux
, map
)) {
11317 verbose(env
, "only one cgroup storage of each type is allowed\n");
11329 /* Basic sanity check before we invest more work here. */
11330 if (!bpf_opcode_in_insntable(insn
->code
)) {
11331 verbose(env
, "unknown opcode %02x\n", insn
->code
);
11336 /* now all pseudo BPF_LD_IMM64 instructions load valid
11337 * 'struct bpf_map *' into a register instead of user map_fd.
11338 * These pointers will be used later by verifier to validate map access.
11343 /* drop refcnt of maps used by the rejected program */
11344 static void release_maps(struct bpf_verifier_env
*env
)
11346 __bpf_free_used_maps(env
->prog
->aux
, env
->used_maps
,
11347 env
->used_map_cnt
);
11350 /* drop refcnt of maps used by the rejected program */
11351 static void release_btfs(struct bpf_verifier_env
*env
)
11353 __bpf_free_used_btfs(env
->prog
->aux
, env
->used_btfs
,
11354 env
->used_btf_cnt
);
11357 /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
11358 static void convert_pseudo_ld_imm64(struct bpf_verifier_env
*env
)
11360 struct bpf_insn
*insn
= env
->prog
->insnsi
;
11361 int insn_cnt
= env
->prog
->len
;
11364 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
11365 if (insn
->code
!= (BPF_LD
| BPF_IMM
| BPF_DW
))
11367 if (insn
->src_reg
== BPF_PSEUDO_FUNC
)
11373 /* single env->prog->insni[off] instruction was replaced with the range
11374 * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying
11375 * [0, off) and [off, end) to new locations, so the patched range stays zero
11377 static int adjust_insn_aux_data(struct bpf_verifier_env
*env
,
11378 struct bpf_prog
*new_prog
, u32 off
, u32 cnt
)
11380 struct bpf_insn_aux_data
*new_data
, *old_data
= env
->insn_aux_data
;
11381 struct bpf_insn
*insn
= new_prog
->insnsi
;
11382 u32 old_seen
= old_data
[off
].seen
;
11386 /* aux info at OFF always needs adjustment, no matter fast path
11387 * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
11388 * original insn at old prog.
11390 old_data
[off
].zext_dst
= insn_has_def32(env
, insn
+ off
+ cnt
- 1);
11394 prog_len
= new_prog
->len
;
11395 new_data
= vzalloc(array_size(prog_len
,
11396 sizeof(struct bpf_insn_aux_data
)));
11399 memcpy(new_data
, old_data
, sizeof(struct bpf_insn_aux_data
) * off
);
11400 memcpy(new_data
+ off
+ cnt
- 1, old_data
+ off
,
11401 sizeof(struct bpf_insn_aux_data
) * (prog_len
- off
- cnt
+ 1));
11402 for (i
= off
; i
< off
+ cnt
- 1; i
++) {
11403 /* Expand insni[off]'s seen count to the patched range. */
11404 new_data
[i
].seen
= old_seen
;
11405 new_data
[i
].zext_dst
= insn_has_def32(env
, insn
+ i
);
11407 env
->insn_aux_data
= new_data
;
11412 static void adjust_subprog_starts(struct bpf_verifier_env
*env
, u32 off
, u32 len
)
11418 /* NOTE: fake 'exit' subprog should be updated as well. */
11419 for (i
= 0; i
<= env
->subprog_cnt
; i
++) {
11420 if (env
->subprog_info
[i
].start
<= off
)
11422 env
->subprog_info
[i
].start
+= len
- 1;
11426 static void adjust_poke_descs(struct bpf_prog
*prog
, u32 len
)
11428 struct bpf_jit_poke_descriptor
*tab
= prog
->aux
->poke_tab
;
11429 int i
, sz
= prog
->aux
->size_poke_tab
;
11430 struct bpf_jit_poke_descriptor
*desc
;
11432 for (i
= 0; i
< sz
; i
++) {
11434 desc
->insn_idx
+= len
- 1;
11438 static struct bpf_prog
*bpf_patch_insn_data(struct bpf_verifier_env
*env
, u32 off
,
11439 const struct bpf_insn
*patch
, u32 len
)
11441 struct bpf_prog
*new_prog
;
11443 new_prog
= bpf_patch_insn_single(env
->prog
, off
, patch
, len
);
11444 if (IS_ERR(new_prog
)) {
11445 if (PTR_ERR(new_prog
) == -ERANGE
)
11447 "insn %d cannot be patched due to 16-bit range\n",
11448 env
->insn_aux_data
[off
].orig_idx
);
11451 if (adjust_insn_aux_data(env
, new_prog
, off
, len
))
11453 adjust_subprog_starts(env
, off
, len
);
11454 adjust_poke_descs(new_prog
, len
);
11458 static int adjust_subprog_starts_after_remove(struct bpf_verifier_env
*env
,
11463 /* find first prog starting at or after off (first to remove) */
11464 for (i
= 0; i
< env
->subprog_cnt
; i
++)
11465 if (env
->subprog_info
[i
].start
>= off
)
11467 /* find first prog starting at or after off + cnt (first to stay) */
11468 for (j
= i
; j
< env
->subprog_cnt
; j
++)
11469 if (env
->subprog_info
[j
].start
>= off
+ cnt
)
11471 /* if j doesn't start exactly at off + cnt, we are just removing
11472 * the front of previous prog
11474 if (env
->subprog_info
[j
].start
!= off
+ cnt
)
11478 struct bpf_prog_aux
*aux
= env
->prog
->aux
;
11481 /* move fake 'exit' subprog as well */
11482 move
= env
->subprog_cnt
+ 1 - j
;
11484 memmove(env
->subprog_info
+ i
,
11485 env
->subprog_info
+ j
,
11486 sizeof(*env
->subprog_info
) * move
);
11487 env
->subprog_cnt
-= j
- i
;
11489 /* remove func_info */
11490 if (aux
->func_info
) {
11491 move
= aux
->func_info_cnt
- j
;
11493 memmove(aux
->func_info
+ i
,
11494 aux
->func_info
+ j
,
11495 sizeof(*aux
->func_info
) * move
);
11496 aux
->func_info_cnt
-= j
- i
;
11497 /* func_info->insn_off is set after all code rewrites,
11498 * in adjust_btf_func() - no need to adjust
11502 /* convert i from "first prog to remove" to "first to adjust" */
11503 if (env
->subprog_info
[i
].start
== off
)
11507 /* update fake 'exit' subprog as well */
11508 for (; i
<= env
->subprog_cnt
; i
++)
11509 env
->subprog_info
[i
].start
-= cnt
;
11514 static int bpf_adj_linfo_after_remove(struct bpf_verifier_env
*env
, u32 off
,
11517 struct bpf_prog
*prog
= env
->prog
;
11518 u32 i
, l_off
, l_cnt
, nr_linfo
;
11519 struct bpf_line_info
*linfo
;
11521 nr_linfo
= prog
->aux
->nr_linfo
;
11525 linfo
= prog
->aux
->linfo
;
11527 /* find first line info to remove, count lines to be removed */
11528 for (i
= 0; i
< nr_linfo
; i
++)
11529 if (linfo
[i
].insn_off
>= off
)
11534 for (; i
< nr_linfo
; i
++)
11535 if (linfo
[i
].insn_off
< off
+ cnt
)
11540 /* First live insn doesn't match first live linfo, it needs to "inherit"
11541 * last removed linfo. prog is already modified, so prog->len == off
11542 * means no live instructions after (tail of the program was removed).
11544 if (prog
->len
!= off
&& l_cnt
&&
11545 (i
== nr_linfo
|| linfo
[i
].insn_off
!= off
+ cnt
)) {
11547 linfo
[--i
].insn_off
= off
+ cnt
;
11550 /* remove the line info which refer to the removed instructions */
11552 memmove(linfo
+ l_off
, linfo
+ i
,
11553 sizeof(*linfo
) * (nr_linfo
- i
));
11555 prog
->aux
->nr_linfo
-= l_cnt
;
11556 nr_linfo
= prog
->aux
->nr_linfo
;
11559 /* pull all linfo[i].insn_off >= off + cnt in by cnt */
11560 for (i
= l_off
; i
< nr_linfo
; i
++)
11561 linfo
[i
].insn_off
-= cnt
;
11563 /* fix up all subprogs (incl. 'exit') which start >= off */
11564 for (i
= 0; i
<= env
->subprog_cnt
; i
++)
11565 if (env
->subprog_info
[i
].linfo_idx
> l_off
) {
11566 /* program may have started in the removed region but
11567 * may not be fully removed
11569 if (env
->subprog_info
[i
].linfo_idx
>= l_off
+ l_cnt
)
11570 env
->subprog_info
[i
].linfo_idx
-= l_cnt
;
11572 env
->subprog_info
[i
].linfo_idx
= l_off
;
11578 static int verifier_remove_insns(struct bpf_verifier_env
*env
, u32 off
, u32 cnt
)
11580 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
11581 unsigned int orig_prog_len
= env
->prog
->len
;
11584 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
11585 bpf_prog_offload_remove_insns(env
, off
, cnt
);
11587 err
= bpf_remove_insns(env
->prog
, off
, cnt
);
11591 err
= adjust_subprog_starts_after_remove(env
, off
, cnt
);
11595 err
= bpf_adj_linfo_after_remove(env
, off
, cnt
);
11599 memmove(aux_data
+ off
, aux_data
+ off
+ cnt
,
11600 sizeof(*aux_data
) * (orig_prog_len
- off
- cnt
));
11605 /* The verifier does more data flow analysis than llvm and will not
11606 * explore branches that are dead at run time. Malicious programs can
11607 * have dead code too. Therefore replace all dead at-run-time code
11610 * Just nops are not optimal, e.g. if they would sit at the end of the
11611 * program and through another bug we would manage to jump there, then
11612 * we'd execute beyond program memory otherwise. Returning exception
11613 * code also wouldn't work since we can have subprogs where the dead
11614 * code could be located.
11616 static void sanitize_dead_code(struct bpf_verifier_env
*env
)
11618 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
11619 struct bpf_insn trap
= BPF_JMP_IMM(BPF_JA
, 0, 0, -1);
11620 struct bpf_insn
*insn
= env
->prog
->insnsi
;
11621 const int insn_cnt
= env
->prog
->len
;
11624 for (i
= 0; i
< insn_cnt
; i
++) {
11625 if (aux_data
[i
].seen
)
11627 memcpy(insn
+ i
, &trap
, sizeof(trap
));
11631 static bool insn_is_cond_jump(u8 code
)
11635 if (BPF_CLASS(code
) == BPF_JMP32
)
11638 if (BPF_CLASS(code
) != BPF_JMP
)
11642 return op
!= BPF_JA
&& op
!= BPF_EXIT
&& op
!= BPF_CALL
;
11645 static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env
*env
)
11647 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
11648 struct bpf_insn ja
= BPF_JMP_IMM(BPF_JA
, 0, 0, 0);
11649 struct bpf_insn
*insn
= env
->prog
->insnsi
;
11650 const int insn_cnt
= env
->prog
->len
;
11653 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
11654 if (!insn_is_cond_jump(insn
->code
))
11657 if (!aux_data
[i
+ 1].seen
)
11658 ja
.off
= insn
->off
;
11659 else if (!aux_data
[i
+ 1 + insn
->off
].seen
)
11664 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
11665 bpf_prog_offload_replace_insn(env
, i
, &ja
);
11667 memcpy(insn
, &ja
, sizeof(ja
));
11671 static int opt_remove_dead_code(struct bpf_verifier_env
*env
)
11673 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
11674 int insn_cnt
= env
->prog
->len
;
11677 for (i
= 0; i
< insn_cnt
; i
++) {
11681 while (i
+ j
< insn_cnt
&& !aux_data
[i
+ j
].seen
)
11686 err
= verifier_remove_insns(env
, i
, j
);
11689 insn_cnt
= env
->prog
->len
;
11695 static int opt_remove_nops(struct bpf_verifier_env
*env
)
11697 const struct bpf_insn ja
= BPF_JMP_IMM(BPF_JA
, 0, 0, 0);
11698 struct bpf_insn
*insn
= env
->prog
->insnsi
;
11699 int insn_cnt
= env
->prog
->len
;
11702 for (i
= 0; i
< insn_cnt
; i
++) {
11703 if (memcmp(&insn
[i
], &ja
, sizeof(ja
)))
11706 err
= verifier_remove_insns(env
, i
, 1);
11716 static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env
*env
,
11717 const union bpf_attr
*attr
)
11719 struct bpf_insn
*patch
, zext_patch
[2], rnd_hi32_patch
[4];
11720 struct bpf_insn_aux_data
*aux
= env
->insn_aux_data
;
11721 int i
, patch_len
, delta
= 0, len
= env
->prog
->len
;
11722 struct bpf_insn
*insns
= env
->prog
->insnsi
;
11723 struct bpf_prog
*new_prog
;
11726 rnd_hi32
= attr
->prog_flags
& BPF_F_TEST_RND_HI32
;
11727 zext_patch
[1] = BPF_ZEXT_REG(0);
11728 rnd_hi32_patch
[1] = BPF_ALU64_IMM(BPF_MOV
, BPF_REG_AX
, 0);
11729 rnd_hi32_patch
[2] = BPF_ALU64_IMM(BPF_LSH
, BPF_REG_AX
, 32);
11730 rnd_hi32_patch
[3] = BPF_ALU64_REG(BPF_OR
, 0, BPF_REG_AX
);
11731 for (i
= 0; i
< len
; i
++) {
11732 int adj_idx
= i
+ delta
;
11733 struct bpf_insn insn
;
11736 insn
= insns
[adj_idx
];
11737 load_reg
= insn_def_regno(&insn
);
11738 if (!aux
[adj_idx
].zext_dst
) {
11746 class = BPF_CLASS(code
);
11747 if (load_reg
== -1)
11750 /* NOTE: arg "reg" (the fourth one) is only used for
11751 * BPF_STX + SRC_OP, so it is safe to pass NULL
11754 if (is_reg64(env
, &insn
, load_reg
, NULL
, DST_OP
)) {
11755 if (class == BPF_LD
&&
11756 BPF_MODE(code
) == BPF_IMM
)
11761 /* ctx load could be transformed into wider load. */
11762 if (class == BPF_LDX
&&
11763 aux
[adj_idx
].ptr_type
== PTR_TO_CTX
)
11766 imm_rnd
= get_random_int();
11767 rnd_hi32_patch
[0] = insn
;
11768 rnd_hi32_patch
[1].imm
= imm_rnd
;
11769 rnd_hi32_patch
[3].dst_reg
= load_reg
;
11770 patch
= rnd_hi32_patch
;
11772 goto apply_patch_buffer
;
11775 /* Add in an zero-extend instruction if a) the JIT has requested
11776 * it or b) it's a CMPXCHG.
11778 * The latter is because: BPF_CMPXCHG always loads a value into
11779 * R0, therefore always zero-extends. However some archs'
11780 * equivalent instruction only does this load when the
11781 * comparison is successful. This detail of CMPXCHG is
11782 * orthogonal to the general zero-extension behaviour of the
11783 * CPU, so it's treated independently of bpf_jit_needs_zext.
11785 if (!bpf_jit_needs_zext() && !is_cmpxchg_insn(&insn
))
11788 if (WARN_ON(load_reg
== -1)) {
11789 verbose(env
, "verifier bug. zext_dst is set, but no reg is defined\n");
11793 zext_patch
[0] = insn
;
11794 zext_patch
[1].dst_reg
= load_reg
;
11795 zext_patch
[1].src_reg
= load_reg
;
11796 patch
= zext_patch
;
11798 apply_patch_buffer
:
11799 new_prog
= bpf_patch_insn_data(env
, adj_idx
, patch
, patch_len
);
11802 env
->prog
= new_prog
;
11803 insns
= new_prog
->insnsi
;
11804 aux
= env
->insn_aux_data
;
11805 delta
+= patch_len
- 1;
11811 /* convert load instructions that access fields of a context type into a
11812 * sequence of instructions that access fields of the underlying structure:
11813 * struct __sk_buff -> struct sk_buff
11814 * struct bpf_sock_ops -> struct sock
11816 static int convert_ctx_accesses(struct bpf_verifier_env
*env
)
11818 const struct bpf_verifier_ops
*ops
= env
->ops
;
11819 int i
, cnt
, size
, ctx_field_size
, delta
= 0;
11820 const int insn_cnt
= env
->prog
->len
;
11821 struct bpf_insn insn_buf
[16], *insn
;
11822 u32 target_size
, size_default
, off
;
11823 struct bpf_prog
*new_prog
;
11824 enum bpf_access_type type
;
11825 bool is_narrower_load
;
11827 if (ops
->gen_prologue
|| env
->seen_direct_write
) {
11828 if (!ops
->gen_prologue
) {
11829 verbose(env
, "bpf verifier is misconfigured\n");
11832 cnt
= ops
->gen_prologue(insn_buf
, env
->seen_direct_write
,
11834 if (cnt
>= ARRAY_SIZE(insn_buf
)) {
11835 verbose(env
, "bpf verifier is misconfigured\n");
11838 new_prog
= bpf_patch_insn_data(env
, 0, insn_buf
, cnt
);
11842 env
->prog
= new_prog
;
11847 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
11850 insn
= env
->prog
->insnsi
+ delta
;
11852 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
11853 bpf_convert_ctx_access_t convert_ctx_access
;
11855 if (insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_B
) ||
11856 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_H
) ||
11857 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_W
) ||
11858 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_DW
))
11860 else if (insn
->code
== (BPF_STX
| BPF_MEM
| BPF_B
) ||
11861 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_H
) ||
11862 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_W
) ||
11863 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_DW
))
11868 if (type
== BPF_WRITE
&&
11869 env
->insn_aux_data
[i
+ delta
].sanitize_stack_off
) {
11870 struct bpf_insn patch
[] = {
11871 /* Sanitize suspicious stack slot with zero.
11872 * There are no memory dependencies for this store,
11873 * since it's only using frame pointer and immediate
11876 BPF_ST_MEM(BPF_DW
, BPF_REG_FP
,
11877 env
->insn_aux_data
[i
+ delta
].sanitize_stack_off
,
11879 /* the original STX instruction will immediately
11880 * overwrite the same stack slot with appropriate value
11885 cnt
= ARRAY_SIZE(patch
);
11886 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, patch
, cnt
);
11891 env
->prog
= new_prog
;
11892 insn
= new_prog
->insnsi
+ i
+ delta
;
11896 switch (env
->insn_aux_data
[i
+ delta
].ptr_type
) {
11898 if (!ops
->convert_ctx_access
)
11900 convert_ctx_access
= ops
->convert_ctx_access
;
11902 case PTR_TO_SOCKET
:
11903 case PTR_TO_SOCK_COMMON
:
11904 convert_ctx_access
= bpf_sock_convert_ctx_access
;
11906 case PTR_TO_TCP_SOCK
:
11907 convert_ctx_access
= bpf_tcp_sock_convert_ctx_access
;
11909 case PTR_TO_XDP_SOCK
:
11910 convert_ctx_access
= bpf_xdp_sock_convert_ctx_access
;
11912 case PTR_TO_BTF_ID
:
11913 if (type
== BPF_READ
) {
11914 insn
->code
= BPF_LDX
| BPF_PROBE_MEM
|
11915 BPF_SIZE((insn
)->code
);
11916 env
->prog
->aux
->num_exentries
++;
11917 } else if (resolve_prog_type(env
->prog
) != BPF_PROG_TYPE_STRUCT_OPS
) {
11918 verbose(env
, "Writes through BTF pointers are not allowed\n");
11926 ctx_field_size
= env
->insn_aux_data
[i
+ delta
].ctx_field_size
;
11927 size
= BPF_LDST_BYTES(insn
);
11929 /* If the read access is a narrower load of the field,
11930 * convert to a 4/8-byte load, to minimum program type specific
11931 * convert_ctx_access changes. If conversion is successful,
11932 * we will apply proper mask to the result.
11934 is_narrower_load
= size
< ctx_field_size
;
11935 size_default
= bpf_ctx_off_adjust_machine(ctx_field_size
);
11937 if (is_narrower_load
) {
11940 if (type
== BPF_WRITE
) {
11941 verbose(env
, "bpf verifier narrow ctx access misconfigured\n");
11946 if (ctx_field_size
== 4)
11948 else if (ctx_field_size
== 8)
11949 size_code
= BPF_DW
;
11951 insn
->off
= off
& ~(size_default
- 1);
11952 insn
->code
= BPF_LDX
| BPF_MEM
| size_code
;
11956 cnt
= convert_ctx_access(type
, insn
, insn_buf
, env
->prog
,
11958 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
) ||
11959 (ctx_field_size
&& !target_size
)) {
11960 verbose(env
, "bpf verifier is misconfigured\n");
11964 if (is_narrower_load
&& size
< target_size
) {
11965 u8 shift
= bpf_ctx_narrow_access_offset(
11966 off
, size
, size_default
) * 8;
11967 if (ctx_field_size
<= 4) {
11969 insn_buf
[cnt
++] = BPF_ALU32_IMM(BPF_RSH
,
11972 insn_buf
[cnt
++] = BPF_ALU32_IMM(BPF_AND
, insn
->dst_reg
,
11973 (1 << size
* 8) - 1);
11976 insn_buf
[cnt
++] = BPF_ALU64_IMM(BPF_RSH
,
11979 insn_buf
[cnt
++] = BPF_ALU64_IMM(BPF_AND
, insn
->dst_reg
,
11980 (1ULL << size
* 8) - 1);
11984 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
11990 /* keep walking new program and skip insns we just inserted */
11991 env
->prog
= new_prog
;
11992 insn
= new_prog
->insnsi
+ i
+ delta
;
11998 static int jit_subprogs(struct bpf_verifier_env
*env
)
12000 struct bpf_prog
*prog
= env
->prog
, **func
, *tmp
;
12001 int i
, j
, subprog_start
, subprog_end
= 0, len
, subprog
;
12002 struct bpf_map
*map_ptr
;
12003 struct bpf_insn
*insn
;
12004 void *old_bpf_func
;
12005 int err
, num_exentries
;
12007 if (env
->subprog_cnt
<= 1)
12010 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
12011 if (bpf_pseudo_func(insn
)) {
12012 env
->insn_aux_data
[i
].call_imm
= insn
->imm
;
12013 /* subprog is encoded in insn[1].imm */
12017 if (!bpf_pseudo_call(insn
))
12019 /* Upon error here we cannot fall back to interpreter but
12020 * need a hard reject of the program. Thus -EFAULT is
12021 * propagated in any case.
12023 subprog
= find_subprog(env
, i
+ insn
->imm
+ 1);
12025 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
12026 i
+ insn
->imm
+ 1);
12029 /* temporarily remember subprog id inside insn instead of
12030 * aux_data, since next loop will split up all insns into funcs
12032 insn
->off
= subprog
;
12033 /* remember original imm in case JIT fails and fallback
12034 * to interpreter will be needed
12036 env
->insn_aux_data
[i
].call_imm
= insn
->imm
;
12037 /* point imm to __bpf_call_base+1 from JITs point of view */
12041 err
= bpf_prog_alloc_jited_linfo(prog
);
12043 goto out_undo_insn
;
12046 func
= kcalloc(env
->subprog_cnt
, sizeof(prog
), GFP_KERNEL
);
12048 goto out_undo_insn
;
12050 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
12051 subprog_start
= subprog_end
;
12052 subprog_end
= env
->subprog_info
[i
+ 1].start
;
12054 len
= subprog_end
- subprog_start
;
12055 /* BPF_PROG_RUN doesn't call subprogs directly,
12056 * hence main prog stats include the runtime of subprogs.
12057 * subprogs don't have IDs and not reachable via prog_get_next_id
12058 * func[i]->stats will never be accessed and stays NULL
12060 func
[i
] = bpf_prog_alloc_no_stats(bpf_prog_size(len
), GFP_USER
);
12063 memcpy(func
[i
]->insnsi
, &prog
->insnsi
[subprog_start
],
12064 len
* sizeof(struct bpf_insn
));
12065 func
[i
]->type
= prog
->type
;
12066 func
[i
]->len
= len
;
12067 if (bpf_prog_calc_tag(func
[i
]))
12069 func
[i
]->is_func
= 1;
12070 func
[i
]->aux
->func_idx
= i
;
12071 /* the btf and func_info will be freed only at prog->aux */
12072 func
[i
]->aux
->btf
= prog
->aux
->btf
;
12073 func
[i
]->aux
->func_info
= prog
->aux
->func_info
;
12075 for (j
= 0; j
< prog
->aux
->size_poke_tab
; j
++) {
12076 u32 insn_idx
= prog
->aux
->poke_tab
[j
].insn_idx
;
12079 if (!(insn_idx
>= subprog_start
&&
12080 insn_idx
<= subprog_end
))
12083 ret
= bpf_jit_add_poke_descriptor(func
[i
],
12084 &prog
->aux
->poke_tab
[j
]);
12086 verbose(env
, "adding tail call poke descriptor failed\n");
12090 func
[i
]->insnsi
[insn_idx
- subprog_start
].imm
= ret
+ 1;
12092 map_ptr
= func
[i
]->aux
->poke_tab
[ret
].tail_call
.map
;
12093 ret
= map_ptr
->ops
->map_poke_track(map_ptr
, func
[i
]->aux
);
12095 verbose(env
, "tracking tail call prog failed\n");
12100 /* Use bpf_prog_F_tag to indicate functions in stack traces.
12101 * Long term would need debug info to populate names
12103 func
[i
]->aux
->name
[0] = 'F';
12104 func
[i
]->aux
->stack_depth
= env
->subprog_info
[i
].stack_depth
;
12105 func
[i
]->jit_requested
= 1;
12106 func
[i
]->aux
->kfunc_tab
= prog
->aux
->kfunc_tab
;
12107 func
[i
]->aux
->linfo
= prog
->aux
->linfo
;
12108 func
[i
]->aux
->nr_linfo
= prog
->aux
->nr_linfo
;
12109 func
[i
]->aux
->jited_linfo
= prog
->aux
->jited_linfo
;
12110 func
[i
]->aux
->linfo_idx
= env
->subprog_info
[i
].linfo_idx
;
12112 insn
= func
[i
]->insnsi
;
12113 for (j
= 0; j
< func
[i
]->len
; j
++, insn
++) {
12114 if (BPF_CLASS(insn
->code
) == BPF_LDX
&&
12115 BPF_MODE(insn
->code
) == BPF_PROBE_MEM
)
12118 func
[i
]->aux
->num_exentries
= num_exentries
;
12119 func
[i
]->aux
->tail_call_reachable
= env
->subprog_info
[i
].tail_call_reachable
;
12120 func
[i
] = bpf_int_jit_compile(func
[i
]);
12121 if (!func
[i
]->jited
) {
12128 /* Untrack main program's aux structs so that during map_poke_run()
12129 * we will not stumble upon the unfilled poke descriptors; each
12130 * of the main program's poke descs got distributed across subprogs
12131 * and got tracked onto map, so we are sure that none of them will
12132 * be missed after the operation below
12134 for (i
= 0; i
< prog
->aux
->size_poke_tab
; i
++) {
12135 map_ptr
= prog
->aux
->poke_tab
[i
].tail_call
.map
;
12137 map_ptr
->ops
->map_poke_untrack(map_ptr
, prog
->aux
);
12140 /* at this point all bpf functions were successfully JITed
12141 * now populate all bpf_calls with correct addresses and
12142 * run last pass of JIT
12144 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
12145 insn
= func
[i
]->insnsi
;
12146 for (j
= 0; j
< func
[i
]->len
; j
++, insn
++) {
12147 if (bpf_pseudo_func(insn
)) {
12148 subprog
= insn
[1].imm
;
12149 insn
[0].imm
= (u32
)(long)func
[subprog
]->bpf_func
;
12150 insn
[1].imm
= ((u64
)(long)func
[subprog
]->bpf_func
) >> 32;
12153 if (!bpf_pseudo_call(insn
))
12155 subprog
= insn
->off
;
12156 insn
->imm
= BPF_CAST_CALL(func
[subprog
]->bpf_func
) -
12160 /* we use the aux data to keep a list of the start addresses
12161 * of the JITed images for each function in the program
12163 * for some architectures, such as powerpc64, the imm field
12164 * might not be large enough to hold the offset of the start
12165 * address of the callee's JITed image from __bpf_call_base
12167 * in such cases, we can lookup the start address of a callee
12168 * by using its subprog id, available from the off field of
12169 * the call instruction, as an index for this list
12171 func
[i
]->aux
->func
= func
;
12172 func
[i
]->aux
->func_cnt
= env
->subprog_cnt
;
12174 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
12175 old_bpf_func
= func
[i
]->bpf_func
;
12176 tmp
= bpf_int_jit_compile(func
[i
]);
12177 if (tmp
!= func
[i
] || func
[i
]->bpf_func
!= old_bpf_func
) {
12178 verbose(env
, "JIT doesn't support bpf-to-bpf calls\n");
12185 /* finally lock prog and jit images for all functions and
12186 * populate kallsysm
12188 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
12189 bpf_prog_lock_ro(func
[i
]);
12190 bpf_prog_kallsyms_add(func
[i
]);
12193 /* Last step: make now unused interpreter insns from main
12194 * prog consistent for later dump requests, so they can
12195 * later look the same as if they were interpreted only.
12197 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
12198 if (bpf_pseudo_func(insn
)) {
12199 insn
[0].imm
= env
->insn_aux_data
[i
].call_imm
;
12200 insn
[1].imm
= find_subprog(env
, i
+ insn
[0].imm
+ 1);
12203 if (!bpf_pseudo_call(insn
))
12205 insn
->off
= env
->insn_aux_data
[i
].call_imm
;
12206 subprog
= find_subprog(env
, i
+ insn
->off
+ 1);
12207 insn
->imm
= subprog
;
12211 prog
->bpf_func
= func
[0]->bpf_func
;
12212 prog
->aux
->func
= func
;
12213 prog
->aux
->func_cnt
= env
->subprog_cnt
;
12214 bpf_prog_jit_attempt_done(prog
);
12217 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
12221 for (j
= 0; j
< func
[i
]->aux
->size_poke_tab
; j
++) {
12222 map_ptr
= func
[i
]->aux
->poke_tab
[j
].tail_call
.map
;
12223 map_ptr
->ops
->map_poke_untrack(map_ptr
, func
[i
]->aux
);
12225 bpf_jit_free(func
[i
]);
12229 /* cleanup main prog to be interpreted */
12230 prog
->jit_requested
= 0;
12231 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
12232 if (!bpf_pseudo_call(insn
))
12235 insn
->imm
= env
->insn_aux_data
[i
].call_imm
;
12237 bpf_prog_jit_attempt_done(prog
);
12241 static int fixup_call_args(struct bpf_verifier_env
*env
)
12243 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
12244 struct bpf_prog
*prog
= env
->prog
;
12245 struct bpf_insn
*insn
= prog
->insnsi
;
12246 bool has_kfunc_call
= bpf_prog_has_kfunc_call(prog
);
12251 if (env
->prog
->jit_requested
&&
12252 !bpf_prog_is_dev_bound(env
->prog
->aux
)) {
12253 err
= jit_subprogs(env
);
12256 if (err
== -EFAULT
)
12259 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
12260 if (has_kfunc_call
) {
12261 verbose(env
, "calling kernel functions are not allowed in non-JITed programs\n");
12264 if (env
->subprog_cnt
> 1 && env
->prog
->aux
->tail_call_reachable
) {
12265 /* When JIT fails the progs with bpf2bpf calls and tail_calls
12266 * have to be rejected, since interpreter doesn't support them yet.
12268 verbose(env
, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
12271 for (i
= 0; i
< prog
->len
; i
++, insn
++) {
12272 if (bpf_pseudo_func(insn
)) {
12273 /* When JIT fails the progs with callback calls
12274 * have to be rejected, since interpreter doesn't support them yet.
12276 verbose(env
, "callbacks are not allowed in non-JITed programs\n");
12280 if (!bpf_pseudo_call(insn
))
12282 depth
= get_callee_stack_depth(env
, insn
, i
);
12285 bpf_patch_call_args(insn
, depth
);
12292 static int fixup_kfunc_call(struct bpf_verifier_env
*env
,
12293 struct bpf_insn
*insn
)
12295 const struct bpf_kfunc_desc
*desc
;
12297 /* insn->imm has the btf func_id. Replace it with
12298 * an address (relative to __bpf_base_call).
12300 desc
= find_kfunc_desc(env
->prog
, insn
->imm
);
12302 verbose(env
, "verifier internal error: kernel function descriptor not found for func_id %u\n",
12307 insn
->imm
= desc
->imm
;
12312 /* Do various post-verification rewrites in a single program pass.
12313 * These rewrites simplify JIT and interpreter implementations.
12315 static int do_misc_fixups(struct bpf_verifier_env
*env
)
12317 struct bpf_prog
*prog
= env
->prog
;
12318 bool expect_blinding
= bpf_jit_blinding_enabled(prog
);
12319 struct bpf_insn
*insn
= prog
->insnsi
;
12320 const struct bpf_func_proto
*fn
;
12321 const int insn_cnt
= prog
->len
;
12322 const struct bpf_map_ops
*ops
;
12323 struct bpf_insn_aux_data
*aux
;
12324 struct bpf_insn insn_buf
[16];
12325 struct bpf_prog
*new_prog
;
12326 struct bpf_map
*map_ptr
;
12327 int i
, ret
, cnt
, delta
= 0;
12329 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
12330 /* Make divide-by-zero exceptions impossible. */
12331 if (insn
->code
== (BPF_ALU64
| BPF_MOD
| BPF_X
) ||
12332 insn
->code
== (BPF_ALU64
| BPF_DIV
| BPF_X
) ||
12333 insn
->code
== (BPF_ALU
| BPF_MOD
| BPF_X
) ||
12334 insn
->code
== (BPF_ALU
| BPF_DIV
| BPF_X
)) {
12335 bool is64
= BPF_CLASS(insn
->code
) == BPF_ALU64
;
12336 bool isdiv
= BPF_OP(insn
->code
) == BPF_DIV
;
12337 struct bpf_insn
*patchlet
;
12338 struct bpf_insn chk_and_div
[] = {
12339 /* [R,W]x div 0 -> 0 */
12340 BPF_RAW_INSN((is64
? BPF_JMP
: BPF_JMP32
) |
12341 BPF_JNE
| BPF_K
, insn
->src_reg
,
12343 BPF_ALU32_REG(BPF_XOR
, insn
->dst_reg
, insn
->dst_reg
),
12344 BPF_JMP_IMM(BPF_JA
, 0, 0, 1),
12347 struct bpf_insn chk_and_mod
[] = {
12348 /* [R,W]x mod 0 -> [R,W]x */
12349 BPF_RAW_INSN((is64
? BPF_JMP
: BPF_JMP32
) |
12350 BPF_JEQ
| BPF_K
, insn
->src_reg
,
12351 0, 1 + (is64
? 0 : 1), 0),
12353 BPF_JMP_IMM(BPF_JA
, 0, 0, 1),
12354 BPF_MOV32_REG(insn
->dst_reg
, insn
->dst_reg
),
12357 patchlet
= isdiv
? chk_and_div
: chk_and_mod
;
12358 cnt
= isdiv
? ARRAY_SIZE(chk_and_div
) :
12359 ARRAY_SIZE(chk_and_mod
) - (is64
? 2 : 0);
12361 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, patchlet
, cnt
);
12366 env
->prog
= prog
= new_prog
;
12367 insn
= new_prog
->insnsi
+ i
+ delta
;
12371 /* Implement LD_ABS and LD_IND with a rewrite, if supported by the program type. */
12372 if (BPF_CLASS(insn
->code
) == BPF_LD
&&
12373 (BPF_MODE(insn
->code
) == BPF_ABS
||
12374 BPF_MODE(insn
->code
) == BPF_IND
)) {
12375 cnt
= env
->ops
->gen_ld_abs(insn
, insn_buf
);
12376 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
)) {
12377 verbose(env
, "bpf verifier is misconfigured\n");
12381 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
12386 env
->prog
= prog
= new_prog
;
12387 insn
= new_prog
->insnsi
+ i
+ delta
;
12391 /* Rewrite pointer arithmetic to mitigate speculation attacks. */
12392 if (insn
->code
== (BPF_ALU64
| BPF_ADD
| BPF_X
) ||
12393 insn
->code
== (BPF_ALU64
| BPF_SUB
| BPF_X
)) {
12394 const u8 code_add
= BPF_ALU64
| BPF_ADD
| BPF_X
;
12395 const u8 code_sub
= BPF_ALU64
| BPF_SUB
| BPF_X
;
12396 struct bpf_insn
*patch
= &insn_buf
[0];
12397 bool issrc
, isneg
, isimm
;
12400 aux
= &env
->insn_aux_data
[i
+ delta
];
12401 if (!aux
->alu_state
||
12402 aux
->alu_state
== BPF_ALU_NON_POINTER
)
12405 isneg
= aux
->alu_state
& BPF_ALU_NEG_VALUE
;
12406 issrc
= (aux
->alu_state
& BPF_ALU_SANITIZE
) ==
12407 BPF_ALU_SANITIZE_SRC
;
12408 isimm
= aux
->alu_state
& BPF_ALU_IMMEDIATE
;
12410 off_reg
= issrc
? insn
->src_reg
: insn
->dst_reg
;
12412 *patch
++ = BPF_MOV32_IMM(BPF_REG_AX
, aux
->alu_limit
);
12415 *patch
++ = BPF_ALU64_IMM(BPF_MUL
, off_reg
, -1);
12416 *patch
++ = BPF_MOV32_IMM(BPF_REG_AX
, aux
->alu_limit
);
12417 *patch
++ = BPF_ALU64_REG(BPF_SUB
, BPF_REG_AX
, off_reg
);
12418 *patch
++ = BPF_ALU64_REG(BPF_OR
, BPF_REG_AX
, off_reg
);
12419 *patch
++ = BPF_ALU64_IMM(BPF_NEG
, BPF_REG_AX
, 0);
12420 *patch
++ = BPF_ALU64_IMM(BPF_ARSH
, BPF_REG_AX
, 63);
12421 *patch
++ = BPF_ALU64_REG(BPF_AND
, BPF_REG_AX
, off_reg
);
12424 *patch
++ = BPF_MOV64_REG(insn
->dst_reg
, insn
->src_reg
);
12425 insn
->src_reg
= BPF_REG_AX
;
12427 insn
->code
= insn
->code
== code_add
?
12428 code_sub
: code_add
;
12430 if (issrc
&& isneg
&& !isimm
)
12431 *patch
++ = BPF_ALU64_IMM(BPF_MUL
, off_reg
, -1);
12432 cnt
= patch
- insn_buf
;
12434 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
12439 env
->prog
= prog
= new_prog
;
12440 insn
= new_prog
->insnsi
+ i
+ delta
;
12444 if (insn
->code
!= (BPF_JMP
| BPF_CALL
))
12446 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
12448 if (insn
->src_reg
== BPF_PSEUDO_KFUNC_CALL
) {
12449 ret
= fixup_kfunc_call(env
, insn
);
12455 if (insn
->imm
== BPF_FUNC_get_route_realm
)
12456 prog
->dst_needed
= 1;
12457 if (insn
->imm
== BPF_FUNC_get_prandom_u32
)
12458 bpf_user_rnd_init_once();
12459 if (insn
->imm
== BPF_FUNC_override_return
)
12460 prog
->kprobe_override
= 1;
12461 if (insn
->imm
== BPF_FUNC_tail_call
) {
12462 /* If we tail call into other programs, we
12463 * cannot make any assumptions since they can
12464 * be replaced dynamically during runtime in
12465 * the program array.
12467 prog
->cb_access
= 1;
12468 if (!allow_tail_call_in_subprogs(env
))
12469 prog
->aux
->stack_depth
= MAX_BPF_STACK
;
12470 prog
->aux
->max_pkt_offset
= MAX_PACKET_OFF
;
12472 /* mark bpf_tail_call as different opcode to avoid
12473 * conditional branch in the interpeter for every normal
12474 * call and to prevent accidental JITing by JIT compiler
12475 * that doesn't support bpf_tail_call yet
12478 insn
->code
= BPF_JMP
| BPF_TAIL_CALL
;
12480 aux
= &env
->insn_aux_data
[i
+ delta
];
12481 if (env
->bpf_capable
&& !expect_blinding
&&
12482 prog
->jit_requested
&&
12483 !bpf_map_key_poisoned(aux
) &&
12484 !bpf_map_ptr_poisoned(aux
) &&
12485 !bpf_map_ptr_unpriv(aux
)) {
12486 struct bpf_jit_poke_descriptor desc
= {
12487 .reason
= BPF_POKE_REASON_TAIL_CALL
,
12488 .tail_call
.map
= BPF_MAP_PTR(aux
->map_ptr_state
),
12489 .tail_call
.key
= bpf_map_key_immediate(aux
),
12490 .insn_idx
= i
+ delta
,
12493 ret
= bpf_jit_add_poke_descriptor(prog
, &desc
);
12495 verbose(env
, "adding tail call poke descriptor failed\n");
12499 insn
->imm
= ret
+ 1;
12503 if (!bpf_map_ptr_unpriv(aux
))
12506 /* instead of changing every JIT dealing with tail_call
12507 * emit two extra insns:
12508 * if (index >= max_entries) goto out;
12509 * index &= array->index_mask;
12510 * to avoid out-of-bounds cpu speculation
12512 if (bpf_map_ptr_poisoned(aux
)) {
12513 verbose(env
, "tail_call abusing map_ptr\n");
12517 map_ptr
= BPF_MAP_PTR(aux
->map_ptr_state
);
12518 insn_buf
[0] = BPF_JMP_IMM(BPF_JGE
, BPF_REG_3
,
12519 map_ptr
->max_entries
, 2);
12520 insn_buf
[1] = BPF_ALU32_IMM(BPF_AND
, BPF_REG_3
,
12521 container_of(map_ptr
,
12524 insn_buf
[2] = *insn
;
12526 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
12531 env
->prog
= prog
= new_prog
;
12532 insn
= new_prog
->insnsi
+ i
+ delta
;
12536 /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
12537 * and other inlining handlers are currently limited to 64 bit
12540 if (prog
->jit_requested
&& BITS_PER_LONG
== 64 &&
12541 (insn
->imm
== BPF_FUNC_map_lookup_elem
||
12542 insn
->imm
== BPF_FUNC_map_update_elem
||
12543 insn
->imm
== BPF_FUNC_map_delete_elem
||
12544 insn
->imm
== BPF_FUNC_map_push_elem
||
12545 insn
->imm
== BPF_FUNC_map_pop_elem
||
12546 insn
->imm
== BPF_FUNC_map_peek_elem
||
12547 insn
->imm
== BPF_FUNC_redirect_map
)) {
12548 aux
= &env
->insn_aux_data
[i
+ delta
];
12549 if (bpf_map_ptr_poisoned(aux
))
12550 goto patch_call_imm
;
12552 map_ptr
= BPF_MAP_PTR(aux
->map_ptr_state
);
12553 ops
= map_ptr
->ops
;
12554 if (insn
->imm
== BPF_FUNC_map_lookup_elem
&&
12555 ops
->map_gen_lookup
) {
12556 cnt
= ops
->map_gen_lookup(map_ptr
, insn_buf
);
12557 if (cnt
== -EOPNOTSUPP
)
12558 goto patch_map_ops_generic
;
12559 if (cnt
<= 0 || cnt
>= ARRAY_SIZE(insn_buf
)) {
12560 verbose(env
, "bpf verifier is misconfigured\n");
12564 new_prog
= bpf_patch_insn_data(env
, i
+ delta
,
12570 env
->prog
= prog
= new_prog
;
12571 insn
= new_prog
->insnsi
+ i
+ delta
;
12575 BUILD_BUG_ON(!__same_type(ops
->map_lookup_elem
,
12576 (void *(*)(struct bpf_map
*map
, void *key
))NULL
));
12577 BUILD_BUG_ON(!__same_type(ops
->map_delete_elem
,
12578 (int (*)(struct bpf_map
*map
, void *key
))NULL
));
12579 BUILD_BUG_ON(!__same_type(ops
->map_update_elem
,
12580 (int (*)(struct bpf_map
*map
, void *key
, void *value
,
12582 BUILD_BUG_ON(!__same_type(ops
->map_push_elem
,
12583 (int (*)(struct bpf_map
*map
, void *value
,
12585 BUILD_BUG_ON(!__same_type(ops
->map_pop_elem
,
12586 (int (*)(struct bpf_map
*map
, void *value
))NULL
));
12587 BUILD_BUG_ON(!__same_type(ops
->map_peek_elem
,
12588 (int (*)(struct bpf_map
*map
, void *value
))NULL
));
12589 BUILD_BUG_ON(!__same_type(ops
->map_redirect
,
12590 (int (*)(struct bpf_map
*map
, u32 ifindex
, u64 flags
))NULL
));
12592 patch_map_ops_generic
:
12593 switch (insn
->imm
) {
12594 case BPF_FUNC_map_lookup_elem
:
12595 insn
->imm
= BPF_CAST_CALL(ops
->map_lookup_elem
) -
12598 case BPF_FUNC_map_update_elem
:
12599 insn
->imm
= BPF_CAST_CALL(ops
->map_update_elem
) -
12602 case BPF_FUNC_map_delete_elem
:
12603 insn
->imm
= BPF_CAST_CALL(ops
->map_delete_elem
) -
12606 case BPF_FUNC_map_push_elem
:
12607 insn
->imm
= BPF_CAST_CALL(ops
->map_push_elem
) -
12610 case BPF_FUNC_map_pop_elem
:
12611 insn
->imm
= BPF_CAST_CALL(ops
->map_pop_elem
) -
12614 case BPF_FUNC_map_peek_elem
:
12615 insn
->imm
= BPF_CAST_CALL(ops
->map_peek_elem
) -
12618 case BPF_FUNC_redirect_map
:
12619 insn
->imm
= BPF_CAST_CALL(ops
->map_redirect
) -
12624 goto patch_call_imm
;
12627 /* Implement bpf_jiffies64 inline. */
12628 if (prog
->jit_requested
&& BITS_PER_LONG
== 64 &&
12629 insn
->imm
== BPF_FUNC_jiffies64
) {
12630 struct bpf_insn ld_jiffies_addr
[2] = {
12631 BPF_LD_IMM64(BPF_REG_0
,
12632 (unsigned long)&jiffies
),
12635 insn_buf
[0] = ld_jiffies_addr
[0];
12636 insn_buf
[1] = ld_jiffies_addr
[1];
12637 insn_buf
[2] = BPF_LDX_MEM(BPF_DW
, BPF_REG_0
,
12641 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
,
12647 env
->prog
= prog
= new_prog
;
12648 insn
= new_prog
->insnsi
+ i
+ delta
;
12653 fn
= env
->ops
->get_func_proto(insn
->imm
, env
->prog
);
12654 /* all functions that have prototype and verifier allowed
12655 * programs to call them, must be real in-kernel functions
12659 "kernel subsystem misconfigured func %s#%d\n",
12660 func_id_name(insn
->imm
), insn
->imm
);
12663 insn
->imm
= fn
->func
- __bpf_call_base
;
12666 /* Since poke tab is now finalized, publish aux to tracker. */
12667 for (i
= 0; i
< prog
->aux
->size_poke_tab
; i
++) {
12668 map_ptr
= prog
->aux
->poke_tab
[i
].tail_call
.map
;
12669 if (!map_ptr
->ops
->map_poke_track
||
12670 !map_ptr
->ops
->map_poke_untrack
||
12671 !map_ptr
->ops
->map_poke_run
) {
12672 verbose(env
, "bpf verifier is misconfigured\n");
12676 ret
= map_ptr
->ops
->map_poke_track(map_ptr
, prog
->aux
);
12678 verbose(env
, "tracking tail call prog failed\n");
12683 sort_kfunc_descs_by_imm(env
->prog
);
12688 static void free_states(struct bpf_verifier_env
*env
)
12690 struct bpf_verifier_state_list
*sl
, *sln
;
12693 sl
= env
->free_list
;
12696 free_verifier_state(&sl
->state
, false);
12700 env
->free_list
= NULL
;
12702 if (!env
->explored_states
)
12705 for (i
= 0; i
< state_htab_size(env
); i
++) {
12706 sl
= env
->explored_states
[i
];
12710 free_verifier_state(&sl
->state
, false);
12714 env
->explored_states
[i
] = NULL
;
12718 /* The verifier is using insn_aux_data[] to store temporary data during
12719 * verification and to store information for passes that run after the
12720 * verification like dead code sanitization. do_check_common() for subprogram N
12721 * may analyze many other subprograms. sanitize_insn_aux_data() clears all
12722 * temporary data after do_check_common() finds that subprogram N cannot be
12723 * verified independently. pass_cnt counts the number of times
12724 * do_check_common() was run and insn->aux->seen tells the pass number
12725 * insn_aux_data was touched. These variables are compared to clear temporary
12726 * data from failed pass. For testing and experiments do_check_common() can be
12727 * run multiple times even when prior attempt to verify is unsuccessful.
12729 * Note that special handling is needed on !env->bypass_spec_v1 if this is
12730 * ever called outside of error path with subsequent program rejection.
12732 static void sanitize_insn_aux_data(struct bpf_verifier_env
*env
)
12734 struct bpf_insn
*insn
= env
->prog
->insnsi
;
12735 struct bpf_insn_aux_data
*aux
;
12738 for (i
= 0; i
< env
->prog
->len
; i
++) {
12739 class = BPF_CLASS(insn
[i
].code
);
12740 if (class != BPF_LDX
&& class != BPF_STX
)
12742 aux
= &env
->insn_aux_data
[i
];
12743 if (aux
->seen
!= env
->pass_cnt
)
12745 memset(aux
, 0, offsetof(typeof(*aux
), orig_idx
));
12749 static int do_check_common(struct bpf_verifier_env
*env
, int subprog
)
12751 bool pop_log
= !(env
->log
.level
& BPF_LOG_LEVEL2
);
12752 struct bpf_verifier_state
*state
;
12753 struct bpf_reg_state
*regs
;
12756 env
->prev_linfo
= NULL
;
12759 state
= kzalloc(sizeof(struct bpf_verifier_state
), GFP_KERNEL
);
12762 state
->curframe
= 0;
12763 state
->speculative
= false;
12764 state
->branches
= 1;
12765 state
->frame
[0] = kzalloc(sizeof(struct bpf_func_state
), GFP_KERNEL
);
12766 if (!state
->frame
[0]) {
12770 env
->cur_state
= state
;
12771 init_func_state(env
, state
->frame
[0],
12772 BPF_MAIN_FUNC
/* callsite */,
12776 regs
= state
->frame
[state
->curframe
]->regs
;
12777 if (subprog
|| env
->prog
->type
== BPF_PROG_TYPE_EXT
) {
12778 ret
= btf_prepare_func_args(env
, subprog
, regs
);
12781 for (i
= BPF_REG_1
; i
<= BPF_REG_5
; i
++) {
12782 if (regs
[i
].type
== PTR_TO_CTX
)
12783 mark_reg_known_zero(env
, regs
, i
);
12784 else if (regs
[i
].type
== SCALAR_VALUE
)
12785 mark_reg_unknown(env
, regs
, i
);
12786 else if (regs
[i
].type
== PTR_TO_MEM_OR_NULL
) {
12787 const u32 mem_size
= regs
[i
].mem_size
;
12789 mark_reg_known_zero(env
, regs
, i
);
12790 regs
[i
].mem_size
= mem_size
;
12791 regs
[i
].id
= ++env
->id_gen
;
12795 /* 1st arg to a function */
12796 regs
[BPF_REG_1
].type
= PTR_TO_CTX
;
12797 mark_reg_known_zero(env
, regs
, BPF_REG_1
);
12798 ret
= btf_check_subprog_arg_match(env
, subprog
, regs
);
12799 if (ret
== -EFAULT
)
12800 /* unlikely verifier bug. abort.
12801 * ret == 0 and ret < 0 are sadly acceptable for
12802 * main() function due to backward compatibility.
12803 * Like socket filter program may be written as:
12804 * int bpf_prog(struct pt_regs *ctx)
12805 * and never dereference that ctx in the program.
12806 * 'struct pt_regs' is a type mismatch for socket
12807 * filter that should be using 'struct __sk_buff'.
12812 ret
= do_check(env
);
12814 /* check for NULL is necessary, since cur_state can be freed inside
12815 * do_check() under memory pressure.
12817 if (env
->cur_state
) {
12818 free_verifier_state(env
->cur_state
, true);
12819 env
->cur_state
= NULL
;
12821 while (!pop_stack(env
, NULL
, NULL
, false));
12822 if (!ret
&& pop_log
)
12823 bpf_vlog_reset(&env
->log
, 0);
12826 /* clean aux data in case subprog was rejected */
12827 sanitize_insn_aux_data(env
);
12831 /* Verify all global functions in a BPF program one by one based on their BTF.
12832 * All global functions must pass verification. Otherwise the whole program is rejected.
12843 * foo() will be verified first for R1=any_scalar_value. During verification it
12844 * will be assumed that bar() already verified successfully and call to bar()
12845 * from foo() will be checked for type match only. Later bar() will be verified
12846 * independently to check that it's safe for R1=any_scalar_value.
12848 static int do_check_subprogs(struct bpf_verifier_env
*env
)
12850 struct bpf_prog_aux
*aux
= env
->prog
->aux
;
12853 if (!aux
->func_info
)
12856 for (i
= 1; i
< env
->subprog_cnt
; i
++) {
12857 if (aux
->func_info_aux
[i
].linkage
!= BTF_FUNC_GLOBAL
)
12859 env
->insn_idx
= env
->subprog_info
[i
].start
;
12860 WARN_ON_ONCE(env
->insn_idx
== 0);
12861 ret
= do_check_common(env
, i
);
12864 } else if (env
->log
.level
& BPF_LOG_LEVEL
) {
12866 "Func#%d is safe for any args that match its prototype\n",
12873 static int do_check_main(struct bpf_verifier_env
*env
)
12878 ret
= do_check_common(env
, 0);
12880 env
->prog
->aux
->stack_depth
= env
->subprog_info
[0].stack_depth
;
12885 static void print_verification_stats(struct bpf_verifier_env
*env
)
12889 if (env
->log
.level
& BPF_LOG_STATS
) {
12890 verbose(env
, "verification time %lld usec\n",
12891 div_u64(env
->verification_time
, 1000));
12892 verbose(env
, "stack depth ");
12893 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
12894 u32 depth
= env
->subprog_info
[i
].stack_depth
;
12896 verbose(env
, "%d", depth
);
12897 if (i
+ 1 < env
->subprog_cnt
)
12900 verbose(env
, "\n");
12902 verbose(env
, "processed %d insns (limit %d) max_states_per_insn %d "
12903 "total_states %d peak_states %d mark_read %d\n",
12904 env
->insn_processed
, BPF_COMPLEXITY_LIMIT_INSNS
,
12905 env
->max_states_per_insn
, env
->total_states
,
12906 env
->peak_states
, env
->longest_mark_read_walk
);
12909 static int check_struct_ops_btf_id(struct bpf_verifier_env
*env
)
12911 const struct btf_type
*t
, *func_proto
;
12912 const struct bpf_struct_ops
*st_ops
;
12913 const struct btf_member
*member
;
12914 struct bpf_prog
*prog
= env
->prog
;
12915 u32 btf_id
, member_idx
;
12918 if (!prog
->gpl_compatible
) {
12919 verbose(env
, "struct ops programs must have a GPL compatible license\n");
12923 btf_id
= prog
->aux
->attach_btf_id
;
12924 st_ops
= bpf_struct_ops_find(btf_id
);
12926 verbose(env
, "attach_btf_id %u is not a supported struct\n",
12932 member_idx
= prog
->expected_attach_type
;
12933 if (member_idx
>= btf_type_vlen(t
)) {
12934 verbose(env
, "attach to invalid member idx %u of struct %s\n",
12935 member_idx
, st_ops
->name
);
12939 member
= &btf_type_member(t
)[member_idx
];
12940 mname
= btf_name_by_offset(btf_vmlinux
, member
->name_off
);
12941 func_proto
= btf_type_resolve_func_ptr(btf_vmlinux
, member
->type
,
12944 verbose(env
, "attach to invalid member %s(@idx %u) of struct %s\n",
12945 mname
, member_idx
, st_ops
->name
);
12949 if (st_ops
->check_member
) {
12950 int err
= st_ops
->check_member(t
, member
);
12953 verbose(env
, "attach to unsupported member %s of struct %s\n",
12954 mname
, st_ops
->name
);
12959 prog
->aux
->attach_func_proto
= func_proto
;
12960 prog
->aux
->attach_func_name
= mname
;
12961 env
->ops
= st_ops
->verifier_ops
;
12965 #define SECURITY_PREFIX "security_"
12967 static int check_attach_modify_return(unsigned long addr
, const char *func_name
)
12969 if (within_error_injection_list(addr
) ||
12970 !strncmp(SECURITY_PREFIX
, func_name
, sizeof(SECURITY_PREFIX
) - 1))
12976 /* list of non-sleepable functions that are otherwise on
12977 * ALLOW_ERROR_INJECTION list
12979 BTF_SET_START(btf_non_sleepable_error_inject
)
12980 /* Three functions below can be called from sleepable and non-sleepable context.
12981 * Assume non-sleepable from bpf safety point of view.
12983 BTF_ID(func
, __add_to_page_cache_locked
)
12984 BTF_ID(func
, should_fail_alloc_page
)
12985 BTF_ID(func
, should_failslab
)
12986 BTF_SET_END(btf_non_sleepable_error_inject
)
12988 static int check_non_sleepable_error_inject(u32 btf_id
)
12990 return btf_id_set_contains(&btf_non_sleepable_error_inject
, btf_id
);
12993 int bpf_check_attach_target(struct bpf_verifier_log
*log
,
12994 const struct bpf_prog
*prog
,
12995 const struct bpf_prog
*tgt_prog
,
12997 struct bpf_attach_target_info
*tgt_info
)
12999 bool prog_extension
= prog
->type
== BPF_PROG_TYPE_EXT
;
13000 const char prefix
[] = "btf_trace_";
13001 int ret
= 0, subprog
= -1, i
;
13002 const struct btf_type
*t
;
13003 bool conservative
= true;
13009 bpf_log(log
, "Tracing programs must provide btf_id\n");
13012 btf
= tgt_prog
? tgt_prog
->aux
->btf
: prog
->aux
->attach_btf
;
13015 "FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
13018 t
= btf_type_by_id(btf
, btf_id
);
13020 bpf_log(log
, "attach_btf_id %u is invalid\n", btf_id
);
13023 tname
= btf_name_by_offset(btf
, t
->name_off
);
13025 bpf_log(log
, "attach_btf_id %u doesn't have a name\n", btf_id
);
13029 struct bpf_prog_aux
*aux
= tgt_prog
->aux
;
13031 for (i
= 0; i
< aux
->func_info_cnt
; i
++)
13032 if (aux
->func_info
[i
].type_id
== btf_id
) {
13036 if (subprog
== -1) {
13037 bpf_log(log
, "Subprog %s doesn't exist\n", tname
);
13040 conservative
= aux
->func_info_aux
[subprog
].unreliable
;
13041 if (prog_extension
) {
13042 if (conservative
) {
13044 "Cannot replace static functions\n");
13047 if (!prog
->jit_requested
) {
13049 "Extension programs should be JITed\n");
13053 if (!tgt_prog
->jited
) {
13054 bpf_log(log
, "Can attach to only JITed progs\n");
13057 if (tgt_prog
->type
== prog
->type
) {
13058 /* Cannot fentry/fexit another fentry/fexit program.
13059 * Cannot attach program extension to another extension.
13060 * It's ok to attach fentry/fexit to extension program.
13062 bpf_log(log
, "Cannot recursively attach\n");
13065 if (tgt_prog
->type
== BPF_PROG_TYPE_TRACING
&&
13067 (tgt_prog
->expected_attach_type
== BPF_TRACE_FENTRY
||
13068 tgt_prog
->expected_attach_type
== BPF_TRACE_FEXIT
)) {
13069 /* Program extensions can extend all program types
13070 * except fentry/fexit. The reason is the following.
13071 * The fentry/fexit programs are used for performance
13072 * analysis, stats and can be attached to any program
13073 * type except themselves. When extension program is
13074 * replacing XDP function it is necessary to allow
13075 * performance analysis of all functions. Both original
13076 * XDP program and its program extension. Hence
13077 * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
13078 * allowed. If extending of fentry/fexit was allowed it
13079 * would be possible to create long call chain
13080 * fentry->extension->fentry->extension beyond
13081 * reasonable stack size. Hence extending fentry is not
13084 bpf_log(log
, "Cannot extend fentry/fexit\n");
13088 if (prog_extension
) {
13089 bpf_log(log
, "Cannot replace kernel functions\n");
13094 switch (prog
->expected_attach_type
) {
13095 case BPF_TRACE_RAW_TP
:
13098 "Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
13101 if (!btf_type_is_typedef(t
)) {
13102 bpf_log(log
, "attach_btf_id %u is not a typedef\n",
13106 if (strncmp(prefix
, tname
, sizeof(prefix
) - 1)) {
13107 bpf_log(log
, "attach_btf_id %u points to wrong type name %s\n",
13111 tname
+= sizeof(prefix
) - 1;
13112 t
= btf_type_by_id(btf
, t
->type
);
13113 if (!btf_type_is_ptr(t
))
13114 /* should never happen in valid vmlinux build */
13116 t
= btf_type_by_id(btf
, t
->type
);
13117 if (!btf_type_is_func_proto(t
))
13118 /* should never happen in valid vmlinux build */
13122 case BPF_TRACE_ITER
:
13123 if (!btf_type_is_func(t
)) {
13124 bpf_log(log
, "attach_btf_id %u is not a function\n",
13128 t
= btf_type_by_id(btf
, t
->type
);
13129 if (!btf_type_is_func_proto(t
))
13131 ret
= btf_distill_func_proto(log
, btf
, t
, tname
, &tgt_info
->fmodel
);
13136 if (!prog_extension
)
13139 case BPF_MODIFY_RETURN
:
13141 case BPF_TRACE_FENTRY
:
13142 case BPF_TRACE_FEXIT
:
13143 if (!btf_type_is_func(t
)) {
13144 bpf_log(log
, "attach_btf_id %u is not a function\n",
13148 if (prog_extension
&&
13149 btf_check_type_match(log
, prog
, btf
, t
))
13151 t
= btf_type_by_id(btf
, t
->type
);
13152 if (!btf_type_is_func_proto(t
))
13155 if ((prog
->aux
->saved_dst_prog_type
|| prog
->aux
->saved_dst_attach_type
) &&
13156 (!tgt_prog
|| prog
->aux
->saved_dst_prog_type
!= tgt_prog
->type
||
13157 prog
->aux
->saved_dst_attach_type
!= tgt_prog
->expected_attach_type
))
13160 if (tgt_prog
&& conservative
)
13163 ret
= btf_distill_func_proto(log
, btf
, t
, tname
, &tgt_info
->fmodel
);
13169 addr
= (long) tgt_prog
->bpf_func
;
13171 addr
= (long) tgt_prog
->aux
->func
[subprog
]->bpf_func
;
13173 addr
= kallsyms_lookup_name(tname
);
13176 "The address of function %s cannot be found\n",
13182 if (prog
->aux
->sleepable
) {
13184 switch (prog
->type
) {
13185 case BPF_PROG_TYPE_TRACING
:
13186 /* fentry/fexit/fmod_ret progs can be sleepable only if they are
13187 * attached to ALLOW_ERROR_INJECTION and are not in denylist.
13189 if (!check_non_sleepable_error_inject(btf_id
) &&
13190 within_error_injection_list(addr
))
13193 case BPF_PROG_TYPE_LSM
:
13194 /* LSM progs check that they are attached to bpf_lsm_*() funcs.
13195 * Only some of them are sleepable.
13197 if (bpf_lsm_is_sleepable_hook(btf_id
))
13204 bpf_log(log
, "%s is not sleepable\n", tname
);
13207 } else if (prog
->expected_attach_type
== BPF_MODIFY_RETURN
) {
13209 bpf_log(log
, "can't modify return codes of BPF programs\n");
13212 ret
= check_attach_modify_return(addr
, tname
);
13214 bpf_log(log
, "%s() is not modifiable\n", tname
);
13221 tgt_info
->tgt_addr
= addr
;
13222 tgt_info
->tgt_name
= tname
;
13223 tgt_info
->tgt_type
= t
;
13227 BTF_SET_START(btf_id_deny
)
13230 BTF_ID(func
, migrate_disable
)
13231 BTF_ID(func
, migrate_enable
)
13233 #if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU
13234 BTF_ID(func
, rcu_read_unlock_strict
)
13236 BTF_SET_END(btf_id_deny
)
13238 static int check_attach_btf_id(struct bpf_verifier_env
*env
)
13240 struct bpf_prog
*prog
= env
->prog
;
13241 struct bpf_prog
*tgt_prog
= prog
->aux
->dst_prog
;
13242 struct bpf_attach_target_info tgt_info
= {};
13243 u32 btf_id
= prog
->aux
->attach_btf_id
;
13244 struct bpf_trampoline
*tr
;
13248 if (prog
->aux
->sleepable
&& prog
->type
!= BPF_PROG_TYPE_TRACING
&&
13249 prog
->type
!= BPF_PROG_TYPE_LSM
) {
13250 verbose(env
, "Only fentry/fexit/fmod_ret and lsm programs can be sleepable\n");
13254 if (prog
->type
== BPF_PROG_TYPE_STRUCT_OPS
)
13255 return check_struct_ops_btf_id(env
);
13257 if (prog
->type
!= BPF_PROG_TYPE_TRACING
&&
13258 prog
->type
!= BPF_PROG_TYPE_LSM
&&
13259 prog
->type
!= BPF_PROG_TYPE_EXT
)
13262 ret
= bpf_check_attach_target(&env
->log
, prog
, tgt_prog
, btf_id
, &tgt_info
);
13266 if (tgt_prog
&& prog
->type
== BPF_PROG_TYPE_EXT
) {
13267 /* to make freplace equivalent to their targets, they need to
13268 * inherit env->ops and expected_attach_type for the rest of the
13271 env
->ops
= bpf_verifier_ops
[tgt_prog
->type
];
13272 prog
->expected_attach_type
= tgt_prog
->expected_attach_type
;
13275 /* store info about the attachment target that will be used later */
13276 prog
->aux
->attach_func_proto
= tgt_info
.tgt_type
;
13277 prog
->aux
->attach_func_name
= tgt_info
.tgt_name
;
13280 prog
->aux
->saved_dst_prog_type
= tgt_prog
->type
;
13281 prog
->aux
->saved_dst_attach_type
= tgt_prog
->expected_attach_type
;
13284 if (prog
->expected_attach_type
== BPF_TRACE_RAW_TP
) {
13285 prog
->aux
->attach_btf_trace
= true;
13287 } else if (prog
->expected_attach_type
== BPF_TRACE_ITER
) {
13288 if (!bpf_iter_prog_supported(prog
))
13293 if (prog
->type
== BPF_PROG_TYPE_LSM
) {
13294 ret
= bpf_lsm_verify_prog(&env
->log
, prog
);
13297 } else if (prog
->type
== BPF_PROG_TYPE_TRACING
&&
13298 btf_id_set_contains(&btf_id_deny
, btf_id
)) {
13302 key
= bpf_trampoline_compute_key(tgt_prog
, prog
->aux
->attach_btf
, btf_id
);
13303 tr
= bpf_trampoline_get(key
, &tgt_info
);
13307 prog
->aux
->dst_trampoline
= tr
;
13311 struct btf
*bpf_get_btf_vmlinux(void)
13313 if (!btf_vmlinux
&& IS_ENABLED(CONFIG_DEBUG_INFO_BTF
)) {
13314 mutex_lock(&bpf_verifier_lock
);
13316 btf_vmlinux
= btf_parse_vmlinux();
13317 mutex_unlock(&bpf_verifier_lock
);
13319 return btf_vmlinux
;
13322 int bpf_check(struct bpf_prog
**prog
, union bpf_attr
*attr
,
13323 union bpf_attr __user
*uattr
)
13325 u64 start_time
= ktime_get_ns();
13326 struct bpf_verifier_env
*env
;
13327 struct bpf_verifier_log
*log
;
13328 int i
, len
, ret
= -EINVAL
;
13331 /* no program is valid */
13332 if (ARRAY_SIZE(bpf_verifier_ops
) == 0)
13335 /* 'struct bpf_verifier_env' can be global, but since it's not small,
13336 * allocate/free it every time bpf_check() is called
13338 env
= kzalloc(sizeof(struct bpf_verifier_env
), GFP_KERNEL
);
13343 len
= (*prog
)->len
;
13344 env
->insn_aux_data
=
13345 vzalloc(array_size(sizeof(struct bpf_insn_aux_data
), len
));
13347 if (!env
->insn_aux_data
)
13349 for (i
= 0; i
< len
; i
++)
13350 env
->insn_aux_data
[i
].orig_idx
= i
;
13352 env
->ops
= bpf_verifier_ops
[env
->prog
->type
];
13353 is_priv
= bpf_capable();
13355 bpf_get_btf_vmlinux();
13357 /* grab the mutex to protect few globals used by verifier */
13359 mutex_lock(&bpf_verifier_lock
);
13361 if (attr
->log_level
|| attr
->log_buf
|| attr
->log_size
) {
13362 /* user requested verbose verifier output
13363 * and supplied buffer to store the verification trace
13365 log
->level
= attr
->log_level
;
13366 log
->ubuf
= (char __user
*) (unsigned long) attr
->log_buf
;
13367 log
->len_total
= attr
->log_size
;
13370 /* log attributes have to be sane */
13371 if (log
->len_total
< 128 || log
->len_total
> UINT_MAX
>> 2 ||
13372 !log
->level
|| !log
->ubuf
|| log
->level
& ~BPF_LOG_MASK
)
13376 if (IS_ERR(btf_vmlinux
)) {
13377 /* Either gcc or pahole or kernel are broken. */
13378 verbose(env
, "in-kernel BTF is malformed\n");
13379 ret
= PTR_ERR(btf_vmlinux
);
13380 goto skip_full_check
;
13383 env
->strict_alignment
= !!(attr
->prog_flags
& BPF_F_STRICT_ALIGNMENT
);
13384 if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
))
13385 env
->strict_alignment
= true;
13386 if (attr
->prog_flags
& BPF_F_ANY_ALIGNMENT
)
13387 env
->strict_alignment
= false;
13389 env
->allow_ptr_leaks
= bpf_allow_ptr_leaks();
13390 env
->allow_uninit_stack
= bpf_allow_uninit_stack();
13391 env
->allow_ptr_to_map_access
= bpf_allow_ptr_to_map_access();
13392 env
->bypass_spec_v1
= bpf_bypass_spec_v1();
13393 env
->bypass_spec_v4
= bpf_bypass_spec_v4();
13394 env
->bpf_capable
= bpf_capable();
13397 env
->test_state_freq
= attr
->prog_flags
& BPF_F_TEST_STATE_FREQ
;
13399 env
->explored_states
= kvcalloc(state_htab_size(env
),
13400 sizeof(struct bpf_verifier_state_list
*),
13403 if (!env
->explored_states
)
13404 goto skip_full_check
;
13406 ret
= add_subprog_and_kfunc(env
);
13408 goto skip_full_check
;
13410 ret
= check_subprogs(env
);
13412 goto skip_full_check
;
13414 ret
= check_btf_info(env
, attr
, uattr
);
13416 goto skip_full_check
;
13418 ret
= check_attach_btf_id(env
);
13420 goto skip_full_check
;
13422 ret
= resolve_pseudo_ldimm64(env
);
13424 goto skip_full_check
;
13426 if (bpf_prog_is_dev_bound(env
->prog
->aux
)) {
13427 ret
= bpf_prog_offload_verifier_prep(env
->prog
);
13429 goto skip_full_check
;
13432 ret
= check_cfg(env
);
13434 goto skip_full_check
;
13436 ret
= do_check_subprogs(env
);
13437 ret
= ret
?: do_check_main(env
);
13439 if (ret
== 0 && bpf_prog_is_dev_bound(env
->prog
->aux
))
13440 ret
= bpf_prog_offload_finalize(env
);
13443 kvfree(env
->explored_states
);
13446 ret
= check_max_stack_depth(env
);
13448 /* instruction rewrites happen after this point */
13451 opt_hard_wire_dead_code_branches(env
);
13453 ret
= opt_remove_dead_code(env
);
13455 ret
= opt_remove_nops(env
);
13458 sanitize_dead_code(env
);
13462 /* program is valid, convert *(u32*)(ctx + off) accesses */
13463 ret
= convert_ctx_accesses(env
);
13466 ret
= do_misc_fixups(env
);
13468 /* do 32-bit optimization after insn patching has done so those patched
13469 * insns could be handled correctly.
13471 if (ret
== 0 && !bpf_prog_is_dev_bound(env
->prog
->aux
)) {
13472 ret
= opt_subreg_zext_lo32_rnd_hi32(env
, attr
);
13473 env
->prog
->aux
->verifier_zext
= bpf_jit_needs_zext() ? !ret
13478 ret
= fixup_call_args(env
);
13480 env
->verification_time
= ktime_get_ns() - start_time
;
13481 print_verification_stats(env
);
13483 if (log
->level
&& bpf_verifier_log_full(log
))
13485 if (log
->level
&& !log
->ubuf
) {
13487 goto err_release_maps
;
13491 goto err_release_maps
;
13493 if (env
->used_map_cnt
) {
13494 /* if program passed verifier, update used_maps in bpf_prog_info */
13495 env
->prog
->aux
->used_maps
= kmalloc_array(env
->used_map_cnt
,
13496 sizeof(env
->used_maps
[0]),
13499 if (!env
->prog
->aux
->used_maps
) {
13501 goto err_release_maps
;
13504 memcpy(env
->prog
->aux
->used_maps
, env
->used_maps
,
13505 sizeof(env
->used_maps
[0]) * env
->used_map_cnt
);
13506 env
->prog
->aux
->used_map_cnt
= env
->used_map_cnt
;
13508 if (env
->used_btf_cnt
) {
13509 /* if program passed verifier, update used_btfs in bpf_prog_aux */
13510 env
->prog
->aux
->used_btfs
= kmalloc_array(env
->used_btf_cnt
,
13511 sizeof(env
->used_btfs
[0]),
13513 if (!env
->prog
->aux
->used_btfs
) {
13515 goto err_release_maps
;
13518 memcpy(env
->prog
->aux
->used_btfs
, env
->used_btfs
,
13519 sizeof(env
->used_btfs
[0]) * env
->used_btf_cnt
);
13520 env
->prog
->aux
->used_btf_cnt
= env
->used_btf_cnt
;
13522 if (env
->used_map_cnt
|| env
->used_btf_cnt
) {
13523 /* program is valid. Convert pseudo bpf_ld_imm64 into generic
13524 * bpf_ld_imm64 instructions
13526 convert_pseudo_ld_imm64(env
);
13529 adjust_btf_func(env
);
13532 if (!env
->prog
->aux
->used_maps
)
13533 /* if we didn't copy map pointers into bpf_prog_info, release
13534 * them now. Otherwise free_used_maps() will release them.
13537 if (!env
->prog
->aux
->used_btfs
)
13540 /* extension progs temporarily inherit the attach_type of their targets
13541 for verification purposes, so set it back to zero before returning
13543 if (env
->prog
->type
== BPF_PROG_TYPE_EXT
)
13544 env
->prog
->expected_attach_type
= 0;
13549 mutex_unlock(&bpf_verifier_lock
);
13550 vfree(env
->insn_aux_data
);