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>
27 static const struct bpf_verifier_ops
* const bpf_verifier_ops
[] = {
28 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
29 [_id] = & _name ## _verifier_ops,
30 #define BPF_MAP_TYPE(_id, _ops)
31 #define BPF_LINK_TYPE(_id, _name)
32 #include <linux/bpf_types.h>
38 /* bpf_check() is a static code analyzer that walks eBPF program
39 * instruction by instruction and updates register/stack state.
40 * All paths of conditional branches are analyzed until 'bpf_exit' insn.
42 * The first pass is depth-first-search to check that the program is a DAG.
43 * It rejects the following programs:
44 * - larger than BPF_MAXINSNS insns
45 * - if loop is present (detected via back-edge)
46 * - unreachable insns exist (shouldn't be a forest. program = one function)
47 * - out of bounds or malformed jumps
48 * The second pass is all possible path descent from the 1st insn.
49 * Since it's analyzing all pathes through the program, the length of the
50 * analysis is limited to 64k insn, which may be hit even if total number of
51 * insn is less then 4K, but there are too many branches that change stack/regs.
52 * Number of 'branches to be analyzed' is limited to 1k
54 * On entry to each instruction, each register has a type, and the instruction
55 * changes the types of the registers depending on instruction semantics.
56 * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
59 * All registers are 64-bit.
60 * R0 - return register
61 * R1-R5 argument passing registers
62 * R6-R9 callee saved registers
63 * R10 - frame pointer read-only
65 * At the start of BPF program the register R1 contains a pointer to bpf_context
66 * and has type PTR_TO_CTX.
68 * Verifier tracks arithmetic operations on pointers in case:
69 * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
70 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
71 * 1st insn copies R10 (which has FRAME_PTR) type into R1
72 * and 2nd arithmetic instruction is pattern matched to recognize
73 * that it wants to construct a pointer to some element within stack.
74 * So after 2nd insn, the register R1 has type PTR_TO_STACK
75 * (and -20 constant is saved for further stack bounds checking).
76 * Meaning that this reg is a pointer to stack plus known immediate constant.
78 * Most of the time the registers have SCALAR_VALUE type, which
79 * means the register has some value, but it's not a valid pointer.
80 * (like pointer plus pointer becomes SCALAR_VALUE type)
82 * When verifier sees load or store instructions the type of base register
83 * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
84 * four pointer types recognized by check_mem_access() function.
86 * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
87 * and the range of [ptr, ptr + map's value_size) is accessible.
89 * registers used to pass values to function calls are checked against
90 * function argument constraints.
92 * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
93 * It means that the register type passed to this function must be
94 * PTR_TO_STACK and it will be used inside the function as
95 * 'pointer to map element key'
97 * For example the argument constraints for bpf_map_lookup_elem():
98 * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
99 * .arg1_type = ARG_CONST_MAP_PTR,
100 * .arg2_type = ARG_PTR_TO_MAP_KEY,
102 * ret_type says that this function returns 'pointer to map elem value or null'
103 * function expects 1st argument to be a const pointer to 'struct bpf_map' and
104 * 2nd argument should be a pointer to stack, which will be used inside
105 * the helper function as a pointer to map element key.
107 * On the kernel side the helper function looks like:
108 * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
110 * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
111 * void *key = (void *) (unsigned long) r2;
114 * here kernel can access 'key' and 'map' pointers safely, knowing that
115 * [key, key + map->key_size) bytes are valid and were initialized on
116 * the stack of eBPF program.
119 * Corresponding eBPF program may look like:
120 * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR
121 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
122 * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP
123 * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
124 * here verifier looks at prototype of map_lookup_elem() and sees:
125 * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
126 * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
128 * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
129 * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
130 * and were initialized prior to this call.
131 * If it's ok, then verifier allows this BPF_CALL insn and looks at
132 * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
133 * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
134 * returns ether pointer to map value or NULL.
136 * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
137 * insn, the register holding that pointer in the true branch changes state to
138 * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
139 * branch. See check_cond_jmp_op().
141 * After the call R0 is set to return type of the function and registers R1-R5
142 * are set to NOT_INIT to indicate that they are no longer readable.
144 * The following reference types represent a potential reference to a kernel
145 * resource which, after first being allocated, must be checked and freed by
147 * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
149 * When the verifier sees a helper call return a reference type, it allocates a
150 * pointer id for the reference and stores it in the current function state.
151 * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
152 * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
153 * passes through a NULL-check conditional. For the branch wherein the state is
154 * changed to CONST_IMM, the verifier releases the reference.
156 * For each helper function that allocates a reference, such as
157 * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
158 * bpf_sk_release(). When a reference type passes into the release function,
159 * the verifier also releases the reference. If any unchecked or unreleased
160 * reference remains at the end of the program, the verifier rejects it.
163 /* verifier_state + insn_idx are pushed to stack when branch is encountered */
164 struct bpf_verifier_stack_elem
{
165 /* verifer state is 'st'
166 * before processing instruction 'insn_idx'
167 * and after processing instruction 'prev_insn_idx'
169 struct bpf_verifier_state st
;
172 struct bpf_verifier_stack_elem
*next
;
173 /* length of verifier log at the time this state was pushed on stack */
177 #define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192
178 #define BPF_COMPLEXITY_LIMIT_STATES 64
180 #define BPF_MAP_KEY_POISON (1ULL << 63)
181 #define BPF_MAP_KEY_SEEN (1ULL << 62)
183 #define BPF_MAP_PTR_UNPRIV 1UL
184 #define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \
185 POISON_POINTER_DELTA))
186 #define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
188 static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data
*aux
)
190 return BPF_MAP_PTR(aux
->map_ptr_state
) == BPF_MAP_PTR_POISON
;
193 static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data
*aux
)
195 return aux
->map_ptr_state
& BPF_MAP_PTR_UNPRIV
;
198 static void bpf_map_ptr_store(struct bpf_insn_aux_data
*aux
,
199 const struct bpf_map
*map
, bool unpriv
)
201 BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON
& BPF_MAP_PTR_UNPRIV
);
202 unpriv
|= bpf_map_ptr_unpriv(aux
);
203 aux
->map_ptr_state
= (unsigned long)map
|
204 (unpriv
? BPF_MAP_PTR_UNPRIV
: 0UL);
207 static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data
*aux
)
209 return aux
->map_key_state
& BPF_MAP_KEY_POISON
;
212 static bool bpf_map_key_unseen(const struct bpf_insn_aux_data
*aux
)
214 return !(aux
->map_key_state
& BPF_MAP_KEY_SEEN
);
217 static u64
bpf_map_key_immediate(const struct bpf_insn_aux_data
*aux
)
219 return aux
->map_key_state
& ~(BPF_MAP_KEY_SEEN
| BPF_MAP_KEY_POISON
);
222 static void bpf_map_key_store(struct bpf_insn_aux_data
*aux
, u64 state
)
224 bool poisoned
= bpf_map_key_poisoned(aux
);
226 aux
->map_key_state
= state
| BPF_MAP_KEY_SEEN
|
227 (poisoned
? BPF_MAP_KEY_POISON
: 0ULL);
230 struct bpf_call_arg_meta
{
231 struct bpf_map
*map_ptr
;
243 struct btf
*btf_vmlinux
;
245 static DEFINE_MUTEX(bpf_verifier_lock
);
247 static const struct bpf_line_info
*
248 find_linfo(const struct bpf_verifier_env
*env
, u32 insn_off
)
250 const struct bpf_line_info
*linfo
;
251 const struct bpf_prog
*prog
;
255 nr_linfo
= prog
->aux
->nr_linfo
;
257 if (!nr_linfo
|| insn_off
>= prog
->len
)
260 linfo
= prog
->aux
->linfo
;
261 for (i
= 1; i
< nr_linfo
; i
++)
262 if (insn_off
< linfo
[i
].insn_off
)
265 return &linfo
[i
- 1];
268 void bpf_verifier_vlog(struct bpf_verifier_log
*log
, const char *fmt
,
273 n
= vscnprintf(log
->kbuf
, BPF_VERIFIER_TMP_LOG_SIZE
, fmt
, args
);
275 WARN_ONCE(n
>= BPF_VERIFIER_TMP_LOG_SIZE
- 1,
276 "verifier log line truncated - local buffer too short\n");
278 n
= min(log
->len_total
- log
->len_used
- 1, n
);
281 if (log
->level
== BPF_LOG_KERNEL
) {
282 pr_err("BPF:%s\n", log
->kbuf
);
285 if (!copy_to_user(log
->ubuf
+ log
->len_used
, log
->kbuf
, n
+ 1))
291 static void bpf_vlog_reset(struct bpf_verifier_log
*log
, u32 new_pos
)
295 if (!bpf_verifier_log_needed(log
))
298 log
->len_used
= new_pos
;
299 if (put_user(zero
, log
->ubuf
+ new_pos
))
303 /* log_level controls verbosity level of eBPF verifier.
304 * bpf_verifier_log_write() is used to dump the verification trace to the log,
305 * so the user can figure out what's wrong with the program
307 __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env
*env
,
308 const char *fmt
, ...)
312 if (!bpf_verifier_log_needed(&env
->log
))
316 bpf_verifier_vlog(&env
->log
, fmt
, args
);
319 EXPORT_SYMBOL_GPL(bpf_verifier_log_write
);
321 __printf(2, 3) static void verbose(void *private_data
, const char *fmt
, ...)
323 struct bpf_verifier_env
*env
= private_data
;
326 if (!bpf_verifier_log_needed(&env
->log
))
330 bpf_verifier_vlog(&env
->log
, fmt
, args
);
334 __printf(2, 3) void bpf_log(struct bpf_verifier_log
*log
,
335 const char *fmt
, ...)
339 if (!bpf_verifier_log_needed(log
))
343 bpf_verifier_vlog(log
, fmt
, args
);
347 static const char *ltrim(const char *s
)
355 __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env
*env
,
357 const char *prefix_fmt
, ...)
359 const struct bpf_line_info
*linfo
;
361 if (!bpf_verifier_log_needed(&env
->log
))
364 linfo
= find_linfo(env
, insn_off
);
365 if (!linfo
|| linfo
== env
->prev_linfo
)
371 va_start(args
, prefix_fmt
);
372 bpf_verifier_vlog(&env
->log
, prefix_fmt
, args
);
377 ltrim(btf_name_by_offset(env
->prog
->aux
->btf
,
380 env
->prev_linfo
= linfo
;
383 static bool type_is_pkt_pointer(enum bpf_reg_type type
)
385 return type
== PTR_TO_PACKET
||
386 type
== PTR_TO_PACKET_META
;
389 static bool type_is_sk_pointer(enum bpf_reg_type type
)
391 return type
== PTR_TO_SOCKET
||
392 type
== PTR_TO_SOCK_COMMON
||
393 type
== PTR_TO_TCP_SOCK
||
394 type
== PTR_TO_XDP_SOCK
;
397 static bool reg_type_not_null(enum bpf_reg_type type
)
399 return type
== PTR_TO_SOCKET
||
400 type
== PTR_TO_TCP_SOCK
||
401 type
== PTR_TO_MAP_VALUE
||
402 type
== PTR_TO_SOCK_COMMON
;
405 static bool reg_type_may_be_null(enum bpf_reg_type type
)
407 return type
== PTR_TO_MAP_VALUE_OR_NULL
||
408 type
== PTR_TO_SOCKET_OR_NULL
||
409 type
== PTR_TO_SOCK_COMMON_OR_NULL
||
410 type
== PTR_TO_TCP_SOCK_OR_NULL
||
411 type
== PTR_TO_BTF_ID_OR_NULL
||
412 type
== PTR_TO_MEM_OR_NULL
||
413 type
== PTR_TO_RDONLY_BUF_OR_NULL
||
414 type
== PTR_TO_RDWR_BUF_OR_NULL
;
417 static bool reg_may_point_to_spin_lock(const struct bpf_reg_state
*reg
)
419 return reg
->type
== PTR_TO_MAP_VALUE
&&
420 map_value_has_spin_lock(reg
->map_ptr
);
423 static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type
)
425 return type
== PTR_TO_SOCKET
||
426 type
== PTR_TO_SOCKET_OR_NULL
||
427 type
== PTR_TO_TCP_SOCK
||
428 type
== PTR_TO_TCP_SOCK_OR_NULL
||
429 type
== PTR_TO_MEM
||
430 type
== PTR_TO_MEM_OR_NULL
;
433 static bool arg_type_may_be_refcounted(enum bpf_arg_type type
)
435 return type
== ARG_PTR_TO_SOCK_COMMON
;
438 /* Determine whether the function releases some resources allocated by another
439 * function call. The first reference type argument will be assumed to be
440 * released by release_reference().
442 static bool is_release_function(enum bpf_func_id func_id
)
444 return func_id
== BPF_FUNC_sk_release
||
445 func_id
== BPF_FUNC_ringbuf_submit
||
446 func_id
== BPF_FUNC_ringbuf_discard
;
449 static bool may_be_acquire_function(enum bpf_func_id func_id
)
451 return func_id
== BPF_FUNC_sk_lookup_tcp
||
452 func_id
== BPF_FUNC_sk_lookup_udp
||
453 func_id
== BPF_FUNC_skc_lookup_tcp
||
454 func_id
== BPF_FUNC_map_lookup_elem
||
455 func_id
== BPF_FUNC_ringbuf_reserve
;
458 static bool is_acquire_function(enum bpf_func_id func_id
,
459 const struct bpf_map
*map
)
461 enum bpf_map_type map_type
= map
? map
->map_type
: BPF_MAP_TYPE_UNSPEC
;
463 if (func_id
== BPF_FUNC_sk_lookup_tcp
||
464 func_id
== BPF_FUNC_sk_lookup_udp
||
465 func_id
== BPF_FUNC_skc_lookup_tcp
||
466 func_id
== BPF_FUNC_ringbuf_reserve
)
469 if (func_id
== BPF_FUNC_map_lookup_elem
&&
470 (map_type
== BPF_MAP_TYPE_SOCKMAP
||
471 map_type
== BPF_MAP_TYPE_SOCKHASH
))
477 static bool is_ptr_cast_function(enum bpf_func_id func_id
)
479 return func_id
== BPF_FUNC_tcp_sock
||
480 func_id
== BPF_FUNC_sk_fullsock
;
483 /* string representation of 'enum bpf_reg_type' */
484 static const char * const reg_type_str
[] = {
486 [SCALAR_VALUE
] = "inv",
487 [PTR_TO_CTX
] = "ctx",
488 [CONST_PTR_TO_MAP
] = "map_ptr",
489 [PTR_TO_MAP_VALUE
] = "map_value",
490 [PTR_TO_MAP_VALUE_OR_NULL
] = "map_value_or_null",
491 [PTR_TO_STACK
] = "fp",
492 [PTR_TO_PACKET
] = "pkt",
493 [PTR_TO_PACKET_META
] = "pkt_meta",
494 [PTR_TO_PACKET_END
] = "pkt_end",
495 [PTR_TO_FLOW_KEYS
] = "flow_keys",
496 [PTR_TO_SOCKET
] = "sock",
497 [PTR_TO_SOCKET_OR_NULL
] = "sock_or_null",
498 [PTR_TO_SOCK_COMMON
] = "sock_common",
499 [PTR_TO_SOCK_COMMON_OR_NULL
] = "sock_common_or_null",
500 [PTR_TO_TCP_SOCK
] = "tcp_sock",
501 [PTR_TO_TCP_SOCK_OR_NULL
] = "tcp_sock_or_null",
502 [PTR_TO_TP_BUFFER
] = "tp_buffer",
503 [PTR_TO_XDP_SOCK
] = "xdp_sock",
504 [PTR_TO_BTF_ID
] = "ptr_",
505 [PTR_TO_BTF_ID_OR_NULL
] = "ptr_or_null_",
506 [PTR_TO_MEM
] = "mem",
507 [PTR_TO_MEM_OR_NULL
] = "mem_or_null",
508 [PTR_TO_RDONLY_BUF
] = "rdonly_buf",
509 [PTR_TO_RDONLY_BUF_OR_NULL
] = "rdonly_buf_or_null",
510 [PTR_TO_RDWR_BUF
] = "rdwr_buf",
511 [PTR_TO_RDWR_BUF_OR_NULL
] = "rdwr_buf_or_null",
514 static char slot_type_char
[] = {
515 [STACK_INVALID
] = '?',
521 static void print_liveness(struct bpf_verifier_env
*env
,
522 enum bpf_reg_liveness live
)
524 if (live
& (REG_LIVE_READ
| REG_LIVE_WRITTEN
| REG_LIVE_DONE
))
526 if (live
& REG_LIVE_READ
)
528 if (live
& REG_LIVE_WRITTEN
)
530 if (live
& REG_LIVE_DONE
)
534 static struct bpf_func_state
*func(struct bpf_verifier_env
*env
,
535 const struct bpf_reg_state
*reg
)
537 struct bpf_verifier_state
*cur
= env
->cur_state
;
539 return cur
->frame
[reg
->frameno
];
542 const char *kernel_type_name(u32 id
)
544 return btf_name_by_offset(btf_vmlinux
,
545 btf_type_by_id(btf_vmlinux
, id
)->name_off
);
548 static void print_verifier_state(struct bpf_verifier_env
*env
,
549 const struct bpf_func_state
*state
)
551 const struct bpf_reg_state
*reg
;
556 verbose(env
, " frame%d:", state
->frameno
);
557 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
558 reg
= &state
->regs
[i
];
562 verbose(env
, " R%d", i
);
563 print_liveness(env
, reg
->live
);
564 verbose(env
, "=%s", reg_type_str
[t
]);
565 if (t
== SCALAR_VALUE
&& reg
->precise
)
567 if ((t
== SCALAR_VALUE
|| t
== PTR_TO_STACK
) &&
568 tnum_is_const(reg
->var_off
)) {
569 /* reg->off should be 0 for SCALAR_VALUE */
570 verbose(env
, "%lld", reg
->var_off
.value
+ reg
->off
);
572 if (t
== PTR_TO_BTF_ID
|| t
== PTR_TO_BTF_ID_OR_NULL
)
573 verbose(env
, "%s", kernel_type_name(reg
->btf_id
));
574 verbose(env
, "(id=%d", reg
->id
);
575 if (reg_type_may_be_refcounted_or_null(t
))
576 verbose(env
, ",ref_obj_id=%d", reg
->ref_obj_id
);
577 if (t
!= SCALAR_VALUE
)
578 verbose(env
, ",off=%d", reg
->off
);
579 if (type_is_pkt_pointer(t
))
580 verbose(env
, ",r=%d", reg
->range
);
581 else if (t
== CONST_PTR_TO_MAP
||
582 t
== PTR_TO_MAP_VALUE
||
583 t
== PTR_TO_MAP_VALUE_OR_NULL
)
584 verbose(env
, ",ks=%d,vs=%d",
585 reg
->map_ptr
->key_size
,
586 reg
->map_ptr
->value_size
);
587 if (tnum_is_const(reg
->var_off
)) {
588 /* Typically an immediate SCALAR_VALUE, but
589 * could be a pointer whose offset is too big
592 verbose(env
, ",imm=%llx", reg
->var_off
.value
);
594 if (reg
->smin_value
!= reg
->umin_value
&&
595 reg
->smin_value
!= S64_MIN
)
596 verbose(env
, ",smin_value=%lld",
597 (long long)reg
->smin_value
);
598 if (reg
->smax_value
!= reg
->umax_value
&&
599 reg
->smax_value
!= S64_MAX
)
600 verbose(env
, ",smax_value=%lld",
601 (long long)reg
->smax_value
);
602 if (reg
->umin_value
!= 0)
603 verbose(env
, ",umin_value=%llu",
604 (unsigned long long)reg
->umin_value
);
605 if (reg
->umax_value
!= U64_MAX
)
606 verbose(env
, ",umax_value=%llu",
607 (unsigned long long)reg
->umax_value
);
608 if (!tnum_is_unknown(reg
->var_off
)) {
611 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
612 verbose(env
, ",var_off=%s", tn_buf
);
614 if (reg
->s32_min_value
!= reg
->smin_value
&&
615 reg
->s32_min_value
!= S32_MIN
)
616 verbose(env
, ",s32_min_value=%d",
617 (int)(reg
->s32_min_value
));
618 if (reg
->s32_max_value
!= reg
->smax_value
&&
619 reg
->s32_max_value
!= S32_MAX
)
620 verbose(env
, ",s32_max_value=%d",
621 (int)(reg
->s32_max_value
));
622 if (reg
->u32_min_value
!= reg
->umin_value
&&
623 reg
->u32_min_value
!= U32_MIN
)
624 verbose(env
, ",u32_min_value=%d",
625 (int)(reg
->u32_min_value
));
626 if (reg
->u32_max_value
!= reg
->umax_value
&&
627 reg
->u32_max_value
!= U32_MAX
)
628 verbose(env
, ",u32_max_value=%d",
629 (int)(reg
->u32_max_value
));
634 for (i
= 0; i
< state
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
635 char types_buf
[BPF_REG_SIZE
+ 1];
639 for (j
= 0; j
< BPF_REG_SIZE
; j
++) {
640 if (state
->stack
[i
].slot_type
[j
] != STACK_INVALID
)
642 types_buf
[j
] = slot_type_char
[
643 state
->stack
[i
].slot_type
[j
]];
645 types_buf
[BPF_REG_SIZE
] = 0;
648 verbose(env
, " fp%d", (-i
- 1) * BPF_REG_SIZE
);
649 print_liveness(env
, state
->stack
[i
].spilled_ptr
.live
);
650 if (state
->stack
[i
].slot_type
[0] == STACK_SPILL
) {
651 reg
= &state
->stack
[i
].spilled_ptr
;
653 verbose(env
, "=%s", reg_type_str
[t
]);
654 if (t
== SCALAR_VALUE
&& reg
->precise
)
656 if (t
== SCALAR_VALUE
&& tnum_is_const(reg
->var_off
))
657 verbose(env
, "%lld", reg
->var_off
.value
+ reg
->off
);
659 verbose(env
, "=%s", types_buf
);
662 if (state
->acquired_refs
&& state
->refs
[0].id
) {
663 verbose(env
, " refs=%d", state
->refs
[0].id
);
664 for (i
= 1; i
< state
->acquired_refs
; i
++)
665 if (state
->refs
[i
].id
)
666 verbose(env
, ",%d", state
->refs
[i
].id
);
671 #define COPY_STATE_FN(NAME, COUNT, FIELD, SIZE) \
672 static int copy_##NAME##_state(struct bpf_func_state *dst, \
673 const struct bpf_func_state *src) \
677 if (WARN_ON_ONCE(dst->COUNT < src->COUNT)) { \
678 /* internal bug, make state invalid to reject the program */ \
679 memset(dst, 0, sizeof(*dst)); \
682 memcpy(dst->FIELD, src->FIELD, \
683 sizeof(*src->FIELD) * (src->COUNT / SIZE)); \
686 /* copy_reference_state() */
687 COPY_STATE_FN(reference
, acquired_refs
, refs
, 1)
688 /* copy_stack_state() */
689 COPY_STATE_FN(stack
, allocated_stack
, stack
, BPF_REG_SIZE
)
692 #define REALLOC_STATE_FN(NAME, COUNT, FIELD, SIZE) \
693 static int realloc_##NAME##_state(struct bpf_func_state *state, int size, \
696 u32 old_size = state->COUNT; \
697 struct bpf_##NAME##_state *new_##FIELD; \
698 int slot = size / SIZE; \
700 if (size <= old_size || !size) { \
703 state->COUNT = slot * SIZE; \
704 if (!size && old_size) { \
705 kfree(state->FIELD); \
706 state->FIELD = NULL; \
710 new_##FIELD = kmalloc_array(slot, sizeof(struct bpf_##NAME##_state), \
716 memcpy(new_##FIELD, state->FIELD, \
717 sizeof(*new_##FIELD) * (old_size / SIZE)); \
718 memset(new_##FIELD + old_size / SIZE, 0, \
719 sizeof(*new_##FIELD) * (size - old_size) / SIZE); \
721 state->COUNT = slot * SIZE; \
722 kfree(state->FIELD); \
723 state->FIELD = new_##FIELD; \
726 /* realloc_reference_state() */
727 REALLOC_STATE_FN(reference
, acquired_refs
, refs
, 1)
728 /* realloc_stack_state() */
729 REALLOC_STATE_FN(stack
, allocated_stack
, stack
, BPF_REG_SIZE
)
730 #undef REALLOC_STATE_FN
732 /* do_check() starts with zero-sized stack in struct bpf_verifier_state to
733 * make it consume minimal amount of memory. check_stack_write() access from
734 * the program calls into realloc_func_state() to grow the stack size.
735 * Note there is a non-zero 'parent' pointer inside bpf_verifier_state
736 * which realloc_stack_state() copies over. It points to previous
737 * bpf_verifier_state which is never reallocated.
739 static int realloc_func_state(struct bpf_func_state
*state
, int stack_size
,
740 int refs_size
, bool copy_old
)
742 int err
= realloc_reference_state(state
, refs_size
, copy_old
);
745 return realloc_stack_state(state
, stack_size
, copy_old
);
748 /* Acquire a pointer id from the env and update the state->refs to include
749 * this new pointer reference.
750 * On success, returns a valid pointer id to associate with the register
751 * On failure, returns a negative errno.
753 static int acquire_reference_state(struct bpf_verifier_env
*env
, int insn_idx
)
755 struct bpf_func_state
*state
= cur_func(env
);
756 int new_ofs
= state
->acquired_refs
;
759 err
= realloc_reference_state(state
, state
->acquired_refs
+ 1, true);
763 state
->refs
[new_ofs
].id
= id
;
764 state
->refs
[new_ofs
].insn_idx
= insn_idx
;
769 /* release function corresponding to acquire_reference_state(). Idempotent. */
770 static int release_reference_state(struct bpf_func_state
*state
, int ptr_id
)
774 last_idx
= state
->acquired_refs
- 1;
775 for (i
= 0; i
< state
->acquired_refs
; i
++) {
776 if (state
->refs
[i
].id
== ptr_id
) {
777 if (last_idx
&& i
!= last_idx
)
778 memcpy(&state
->refs
[i
], &state
->refs
[last_idx
],
779 sizeof(*state
->refs
));
780 memset(&state
->refs
[last_idx
], 0, sizeof(*state
->refs
));
781 state
->acquired_refs
--;
788 static int transfer_reference_state(struct bpf_func_state
*dst
,
789 struct bpf_func_state
*src
)
791 int err
= realloc_reference_state(dst
, src
->acquired_refs
, false);
794 err
= copy_reference_state(dst
, src
);
800 static void free_func_state(struct bpf_func_state
*state
)
809 static void clear_jmp_history(struct bpf_verifier_state
*state
)
811 kfree(state
->jmp_history
);
812 state
->jmp_history
= NULL
;
813 state
->jmp_history_cnt
= 0;
816 static void free_verifier_state(struct bpf_verifier_state
*state
,
821 for (i
= 0; i
<= state
->curframe
; i
++) {
822 free_func_state(state
->frame
[i
]);
823 state
->frame
[i
] = NULL
;
825 clear_jmp_history(state
);
830 /* copy verifier state from src to dst growing dst stack space
831 * when necessary to accommodate larger src stack
833 static int copy_func_state(struct bpf_func_state
*dst
,
834 const struct bpf_func_state
*src
)
838 err
= realloc_func_state(dst
, src
->allocated_stack
, src
->acquired_refs
,
842 memcpy(dst
, src
, offsetof(struct bpf_func_state
, acquired_refs
));
843 err
= copy_reference_state(dst
, src
);
846 return copy_stack_state(dst
, src
);
849 static int copy_verifier_state(struct bpf_verifier_state
*dst_state
,
850 const struct bpf_verifier_state
*src
)
852 struct bpf_func_state
*dst
;
853 u32 jmp_sz
= sizeof(struct bpf_idx_pair
) * src
->jmp_history_cnt
;
856 if (dst_state
->jmp_history_cnt
< src
->jmp_history_cnt
) {
857 kfree(dst_state
->jmp_history
);
858 dst_state
->jmp_history
= kmalloc(jmp_sz
, GFP_USER
);
859 if (!dst_state
->jmp_history
)
862 memcpy(dst_state
->jmp_history
, src
->jmp_history
, jmp_sz
);
863 dst_state
->jmp_history_cnt
= src
->jmp_history_cnt
;
865 /* if dst has more stack frames then src frame, free them */
866 for (i
= src
->curframe
+ 1; i
<= dst_state
->curframe
; i
++) {
867 free_func_state(dst_state
->frame
[i
]);
868 dst_state
->frame
[i
] = NULL
;
870 dst_state
->speculative
= src
->speculative
;
871 dst_state
->curframe
= src
->curframe
;
872 dst_state
->active_spin_lock
= src
->active_spin_lock
;
873 dst_state
->branches
= src
->branches
;
874 dst_state
->parent
= src
->parent
;
875 dst_state
->first_insn_idx
= src
->first_insn_idx
;
876 dst_state
->last_insn_idx
= src
->last_insn_idx
;
877 for (i
= 0; i
<= src
->curframe
; i
++) {
878 dst
= dst_state
->frame
[i
];
880 dst
= kzalloc(sizeof(*dst
), GFP_KERNEL
);
883 dst_state
->frame
[i
] = dst
;
885 err
= copy_func_state(dst
, src
->frame
[i
]);
892 static void update_branch_counts(struct bpf_verifier_env
*env
, struct bpf_verifier_state
*st
)
895 u32 br
= --st
->branches
;
897 /* WARN_ON(br > 1) technically makes sense here,
898 * but see comment in push_stack(), hence:
900 WARN_ONCE((int)br
< 0,
901 "BUG update_branch_counts:branches_to_explore=%d\n",
909 static int pop_stack(struct bpf_verifier_env
*env
, int *prev_insn_idx
,
910 int *insn_idx
, bool pop_log
)
912 struct bpf_verifier_state
*cur
= env
->cur_state
;
913 struct bpf_verifier_stack_elem
*elem
, *head
= env
->head
;
916 if (env
->head
== NULL
)
920 err
= copy_verifier_state(cur
, &head
->st
);
925 bpf_vlog_reset(&env
->log
, head
->log_pos
);
927 *insn_idx
= head
->insn_idx
;
929 *prev_insn_idx
= head
->prev_insn_idx
;
931 free_verifier_state(&head
->st
, false);
938 static struct bpf_verifier_state
*push_stack(struct bpf_verifier_env
*env
,
939 int insn_idx
, int prev_insn_idx
,
942 struct bpf_verifier_state
*cur
= env
->cur_state
;
943 struct bpf_verifier_stack_elem
*elem
;
946 elem
= kzalloc(sizeof(struct bpf_verifier_stack_elem
), GFP_KERNEL
);
950 elem
->insn_idx
= insn_idx
;
951 elem
->prev_insn_idx
= prev_insn_idx
;
952 elem
->next
= env
->head
;
953 elem
->log_pos
= env
->log
.len_used
;
956 err
= copy_verifier_state(&elem
->st
, cur
);
959 elem
->st
.speculative
|= speculative
;
960 if (env
->stack_size
> BPF_COMPLEXITY_LIMIT_JMP_SEQ
) {
961 verbose(env
, "The sequence of %d jumps is too complex.\n",
965 if (elem
->st
.parent
) {
966 ++elem
->st
.parent
->branches
;
967 /* WARN_ON(branches > 2) technically makes sense here,
969 * 1. speculative states will bump 'branches' for non-branch
971 * 2. is_state_visited() heuristics may decide not to create
972 * a new state for a sequence of branches and all such current
973 * and cloned states will be pointing to a single parent state
974 * which might have large 'branches' count.
979 free_verifier_state(env
->cur_state
, true);
980 env
->cur_state
= NULL
;
981 /* pop all elements and return */
982 while (!pop_stack(env
, NULL
, NULL
, false));
986 #define CALLER_SAVED_REGS 6
987 static const int caller_saved
[CALLER_SAVED_REGS
] = {
988 BPF_REG_0
, BPF_REG_1
, BPF_REG_2
, BPF_REG_3
, BPF_REG_4
, BPF_REG_5
991 static void __mark_reg_not_init(const struct bpf_verifier_env
*env
,
992 struct bpf_reg_state
*reg
);
994 /* Mark the unknown part of a register (variable offset or scalar value) as
995 * known to have the value @imm.
997 static void __mark_reg_known(struct bpf_reg_state
*reg
, u64 imm
)
999 /* Clear id, off, and union(map_ptr, range) */
1000 memset(((u8
*)reg
) + sizeof(reg
->type
), 0,
1001 offsetof(struct bpf_reg_state
, var_off
) - sizeof(reg
->type
));
1002 reg
->var_off
= tnum_const(imm
);
1003 reg
->smin_value
= (s64
)imm
;
1004 reg
->smax_value
= (s64
)imm
;
1005 reg
->umin_value
= imm
;
1006 reg
->umax_value
= imm
;
1008 reg
->s32_min_value
= (s32
)imm
;
1009 reg
->s32_max_value
= (s32
)imm
;
1010 reg
->u32_min_value
= (u32
)imm
;
1011 reg
->u32_max_value
= (u32
)imm
;
1014 static void __mark_reg32_known(struct bpf_reg_state
*reg
, u64 imm
)
1016 reg
->var_off
= tnum_const_subreg(reg
->var_off
, imm
);
1017 reg
->s32_min_value
= (s32
)imm
;
1018 reg
->s32_max_value
= (s32
)imm
;
1019 reg
->u32_min_value
= (u32
)imm
;
1020 reg
->u32_max_value
= (u32
)imm
;
1023 /* Mark the 'variable offset' part of a register as zero. This should be
1024 * used only on registers holding a pointer type.
1026 static void __mark_reg_known_zero(struct bpf_reg_state
*reg
)
1028 __mark_reg_known(reg
, 0);
1031 static void __mark_reg_const_zero(struct bpf_reg_state
*reg
)
1033 __mark_reg_known(reg
, 0);
1034 reg
->type
= SCALAR_VALUE
;
1037 static void mark_reg_known_zero(struct bpf_verifier_env
*env
,
1038 struct bpf_reg_state
*regs
, u32 regno
)
1040 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
1041 verbose(env
, "mark_reg_known_zero(regs, %u)\n", regno
);
1042 /* Something bad happened, let's kill all regs */
1043 for (regno
= 0; regno
< MAX_BPF_REG
; regno
++)
1044 __mark_reg_not_init(env
, regs
+ regno
);
1047 __mark_reg_known_zero(regs
+ regno
);
1050 static bool reg_is_pkt_pointer(const struct bpf_reg_state
*reg
)
1052 return type_is_pkt_pointer(reg
->type
);
1055 static bool reg_is_pkt_pointer_any(const struct bpf_reg_state
*reg
)
1057 return reg_is_pkt_pointer(reg
) ||
1058 reg
->type
== PTR_TO_PACKET_END
;
1061 /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
1062 static bool reg_is_init_pkt_pointer(const struct bpf_reg_state
*reg
,
1063 enum bpf_reg_type which
)
1065 /* The register can already have a range from prior markings.
1066 * This is fine as long as it hasn't been advanced from its
1069 return reg
->type
== which
&&
1072 tnum_equals_const(reg
->var_off
, 0);
1075 /* Reset the min/max bounds of a register */
1076 static void __mark_reg_unbounded(struct bpf_reg_state
*reg
)
1078 reg
->smin_value
= S64_MIN
;
1079 reg
->smax_value
= S64_MAX
;
1080 reg
->umin_value
= 0;
1081 reg
->umax_value
= U64_MAX
;
1083 reg
->s32_min_value
= S32_MIN
;
1084 reg
->s32_max_value
= S32_MAX
;
1085 reg
->u32_min_value
= 0;
1086 reg
->u32_max_value
= U32_MAX
;
1089 static void __mark_reg64_unbounded(struct bpf_reg_state
*reg
)
1091 reg
->smin_value
= S64_MIN
;
1092 reg
->smax_value
= S64_MAX
;
1093 reg
->umin_value
= 0;
1094 reg
->umax_value
= U64_MAX
;
1097 static void __mark_reg32_unbounded(struct bpf_reg_state
*reg
)
1099 reg
->s32_min_value
= S32_MIN
;
1100 reg
->s32_max_value
= S32_MAX
;
1101 reg
->u32_min_value
= 0;
1102 reg
->u32_max_value
= U32_MAX
;
1105 static void __update_reg32_bounds(struct bpf_reg_state
*reg
)
1107 struct tnum var32_off
= tnum_subreg(reg
->var_off
);
1109 /* min signed is max(sign bit) | min(other bits) */
1110 reg
->s32_min_value
= max_t(s32
, reg
->s32_min_value
,
1111 var32_off
.value
| (var32_off
.mask
& S32_MIN
));
1112 /* max signed is min(sign bit) | max(other bits) */
1113 reg
->s32_max_value
= min_t(s32
, reg
->s32_max_value
,
1114 var32_off
.value
| (var32_off
.mask
& S32_MAX
));
1115 reg
->u32_min_value
= max_t(u32
, reg
->u32_min_value
, (u32
)var32_off
.value
);
1116 reg
->u32_max_value
= min(reg
->u32_max_value
,
1117 (u32
)(var32_off
.value
| var32_off
.mask
));
1120 static void __update_reg64_bounds(struct bpf_reg_state
*reg
)
1122 /* min signed is max(sign bit) | min(other bits) */
1123 reg
->smin_value
= max_t(s64
, reg
->smin_value
,
1124 reg
->var_off
.value
| (reg
->var_off
.mask
& S64_MIN
));
1125 /* max signed is min(sign bit) | max(other bits) */
1126 reg
->smax_value
= min_t(s64
, reg
->smax_value
,
1127 reg
->var_off
.value
| (reg
->var_off
.mask
& S64_MAX
));
1128 reg
->umin_value
= max(reg
->umin_value
, reg
->var_off
.value
);
1129 reg
->umax_value
= min(reg
->umax_value
,
1130 reg
->var_off
.value
| reg
->var_off
.mask
);
1133 static void __update_reg_bounds(struct bpf_reg_state
*reg
)
1135 __update_reg32_bounds(reg
);
1136 __update_reg64_bounds(reg
);
1139 /* Uses signed min/max values to inform unsigned, and vice-versa */
1140 static void __reg32_deduce_bounds(struct bpf_reg_state
*reg
)
1142 /* Learn sign from signed bounds.
1143 * If we cannot cross the sign boundary, then signed and unsigned bounds
1144 * are the same, so combine. This works even in the negative case, e.g.
1145 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
1147 if (reg
->s32_min_value
>= 0 || reg
->s32_max_value
< 0) {
1148 reg
->s32_min_value
= reg
->u32_min_value
=
1149 max_t(u32
, reg
->s32_min_value
, reg
->u32_min_value
);
1150 reg
->s32_max_value
= reg
->u32_max_value
=
1151 min_t(u32
, reg
->s32_max_value
, reg
->u32_max_value
);
1154 /* Learn sign from unsigned bounds. Signed bounds cross the sign
1155 * boundary, so we must be careful.
1157 if ((s32
)reg
->u32_max_value
>= 0) {
1158 /* Positive. We can't learn anything from the smin, but smax
1159 * is positive, hence safe.
1161 reg
->s32_min_value
= reg
->u32_min_value
;
1162 reg
->s32_max_value
= reg
->u32_max_value
=
1163 min_t(u32
, reg
->s32_max_value
, reg
->u32_max_value
);
1164 } else if ((s32
)reg
->u32_min_value
< 0) {
1165 /* Negative. We can't learn anything from the smax, but smin
1166 * is negative, hence safe.
1168 reg
->s32_min_value
= reg
->u32_min_value
=
1169 max_t(u32
, reg
->s32_min_value
, reg
->u32_min_value
);
1170 reg
->s32_max_value
= reg
->u32_max_value
;
1174 static void __reg64_deduce_bounds(struct bpf_reg_state
*reg
)
1176 /* Learn sign from signed bounds.
1177 * If we cannot cross the sign boundary, then signed and unsigned bounds
1178 * are the same, so combine. This works even in the negative case, e.g.
1179 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
1181 if (reg
->smin_value
>= 0 || reg
->smax_value
< 0) {
1182 reg
->smin_value
= reg
->umin_value
= max_t(u64
, reg
->smin_value
,
1184 reg
->smax_value
= reg
->umax_value
= min_t(u64
, reg
->smax_value
,
1188 /* Learn sign from unsigned bounds. Signed bounds cross the sign
1189 * boundary, so we must be careful.
1191 if ((s64
)reg
->umax_value
>= 0) {
1192 /* Positive. We can't learn anything from the smin, but smax
1193 * is positive, hence safe.
1195 reg
->smin_value
= reg
->umin_value
;
1196 reg
->smax_value
= reg
->umax_value
= min_t(u64
, reg
->smax_value
,
1198 } else if ((s64
)reg
->umin_value
< 0) {
1199 /* Negative. We can't learn anything from the smax, but smin
1200 * is negative, hence safe.
1202 reg
->smin_value
= reg
->umin_value
= max_t(u64
, reg
->smin_value
,
1204 reg
->smax_value
= reg
->umax_value
;
1208 static void __reg_deduce_bounds(struct bpf_reg_state
*reg
)
1210 __reg32_deduce_bounds(reg
);
1211 __reg64_deduce_bounds(reg
);
1214 /* Attempts to improve var_off based on unsigned min/max information */
1215 static void __reg_bound_offset(struct bpf_reg_state
*reg
)
1217 struct tnum var64_off
= tnum_intersect(reg
->var_off
,
1218 tnum_range(reg
->umin_value
,
1220 struct tnum var32_off
= tnum_intersect(tnum_subreg(reg
->var_off
),
1221 tnum_range(reg
->u32_min_value
,
1222 reg
->u32_max_value
));
1224 reg
->var_off
= tnum_or(tnum_clear_subreg(var64_off
), var32_off
);
1227 static void __reg_assign_32_into_64(struct bpf_reg_state
*reg
)
1229 reg
->umin_value
= reg
->u32_min_value
;
1230 reg
->umax_value
= reg
->u32_max_value
;
1231 /* Attempt to pull 32-bit signed bounds into 64-bit bounds
1232 * but must be positive otherwise set to worse case bounds
1233 * and refine later from tnum.
1235 if (reg
->s32_min_value
>= 0 && reg
->s32_max_value
>= 0)
1236 reg
->smax_value
= reg
->s32_max_value
;
1238 reg
->smax_value
= U32_MAX
;
1239 if (reg
->s32_min_value
>= 0)
1240 reg
->smin_value
= reg
->s32_min_value
;
1242 reg
->smin_value
= 0;
1245 static void __reg_combine_32_into_64(struct bpf_reg_state
*reg
)
1247 /* special case when 64-bit register has upper 32-bit register
1248 * zeroed. Typically happens after zext or <<32, >>32 sequence
1249 * allowing us to use 32-bit bounds directly,
1251 if (tnum_equals_const(tnum_clear_subreg(reg
->var_off
), 0)) {
1252 __reg_assign_32_into_64(reg
);
1254 /* Otherwise the best we can do is push lower 32bit known and
1255 * unknown bits into register (var_off set from jmp logic)
1256 * then learn as much as possible from the 64-bit tnum
1257 * known and unknown bits. The previous smin/smax bounds are
1258 * invalid here because of jmp32 compare so mark them unknown
1259 * so they do not impact tnum bounds calculation.
1261 __mark_reg64_unbounded(reg
);
1262 __update_reg_bounds(reg
);
1265 /* Intersecting with the old var_off might have improved our bounds
1266 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
1267 * then new var_off is (0; 0x7f...fc) which improves our umax.
1269 __reg_deduce_bounds(reg
);
1270 __reg_bound_offset(reg
);
1271 __update_reg_bounds(reg
);
1274 static bool __reg64_bound_s32(s64 a
)
1276 if (a
> S32_MIN
&& a
< S32_MAX
)
1281 static bool __reg64_bound_u32(u64 a
)
1283 if (a
> U32_MIN
&& a
< U32_MAX
)
1288 static void __reg_combine_64_into_32(struct bpf_reg_state
*reg
)
1290 __mark_reg32_unbounded(reg
);
1292 if (__reg64_bound_s32(reg
->smin_value
))
1293 reg
->s32_min_value
= (s32
)reg
->smin_value
;
1294 if (__reg64_bound_s32(reg
->smax_value
))
1295 reg
->s32_max_value
= (s32
)reg
->smax_value
;
1296 if (__reg64_bound_u32(reg
->umin_value
))
1297 reg
->u32_min_value
= (u32
)reg
->umin_value
;
1298 if (__reg64_bound_u32(reg
->umax_value
))
1299 reg
->u32_max_value
= (u32
)reg
->umax_value
;
1301 /* Intersecting with the old var_off might have improved our bounds
1302 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
1303 * then new var_off is (0; 0x7f...fc) which improves our umax.
1305 __reg_deduce_bounds(reg
);
1306 __reg_bound_offset(reg
);
1307 __update_reg_bounds(reg
);
1310 /* Mark a register as having a completely unknown (scalar) value. */
1311 static void __mark_reg_unknown(const struct bpf_verifier_env
*env
,
1312 struct bpf_reg_state
*reg
)
1315 * Clear type, id, off, and union(map_ptr, range) and
1316 * padding between 'type' and union
1318 memset(reg
, 0, offsetof(struct bpf_reg_state
, var_off
));
1319 reg
->type
= SCALAR_VALUE
;
1320 reg
->var_off
= tnum_unknown
;
1322 reg
->precise
= env
->subprog_cnt
> 1 || !env
->bpf_capable
;
1323 __mark_reg_unbounded(reg
);
1326 static void mark_reg_unknown(struct bpf_verifier_env
*env
,
1327 struct bpf_reg_state
*regs
, u32 regno
)
1329 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
1330 verbose(env
, "mark_reg_unknown(regs, %u)\n", regno
);
1331 /* Something bad happened, let's kill all regs except FP */
1332 for (regno
= 0; regno
< BPF_REG_FP
; regno
++)
1333 __mark_reg_not_init(env
, regs
+ regno
);
1336 __mark_reg_unknown(env
, regs
+ regno
);
1339 static void __mark_reg_not_init(const struct bpf_verifier_env
*env
,
1340 struct bpf_reg_state
*reg
)
1342 __mark_reg_unknown(env
, reg
);
1343 reg
->type
= NOT_INIT
;
1346 static void mark_reg_not_init(struct bpf_verifier_env
*env
,
1347 struct bpf_reg_state
*regs
, u32 regno
)
1349 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
1350 verbose(env
, "mark_reg_not_init(regs, %u)\n", regno
);
1351 /* Something bad happened, let's kill all regs except FP */
1352 for (regno
= 0; regno
< BPF_REG_FP
; regno
++)
1353 __mark_reg_not_init(env
, regs
+ regno
);
1356 __mark_reg_not_init(env
, regs
+ regno
);
1359 static void mark_btf_ld_reg(struct bpf_verifier_env
*env
,
1360 struct bpf_reg_state
*regs
, u32 regno
,
1361 enum bpf_reg_type reg_type
, u32 btf_id
)
1363 if (reg_type
== SCALAR_VALUE
) {
1364 mark_reg_unknown(env
, regs
, regno
);
1367 mark_reg_known_zero(env
, regs
, regno
);
1368 regs
[regno
].type
= PTR_TO_BTF_ID
;
1369 regs
[regno
].btf_id
= btf_id
;
1372 #define DEF_NOT_SUBREG (0)
1373 static void init_reg_state(struct bpf_verifier_env
*env
,
1374 struct bpf_func_state
*state
)
1376 struct bpf_reg_state
*regs
= state
->regs
;
1379 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
1380 mark_reg_not_init(env
, regs
, i
);
1381 regs
[i
].live
= REG_LIVE_NONE
;
1382 regs
[i
].parent
= NULL
;
1383 regs
[i
].subreg_def
= DEF_NOT_SUBREG
;
1387 regs
[BPF_REG_FP
].type
= PTR_TO_STACK
;
1388 mark_reg_known_zero(env
, regs
, BPF_REG_FP
);
1389 regs
[BPF_REG_FP
].frameno
= state
->frameno
;
1392 #define BPF_MAIN_FUNC (-1)
1393 static void init_func_state(struct bpf_verifier_env
*env
,
1394 struct bpf_func_state
*state
,
1395 int callsite
, int frameno
, int subprogno
)
1397 state
->callsite
= callsite
;
1398 state
->frameno
= frameno
;
1399 state
->subprogno
= subprogno
;
1400 init_reg_state(env
, state
);
1404 SRC_OP
, /* register is used as source operand */
1405 DST_OP
, /* register is used as destination operand */
1406 DST_OP_NO_MARK
/* same as above, check only, don't mark */
1409 static int cmp_subprogs(const void *a
, const void *b
)
1411 return ((struct bpf_subprog_info
*)a
)->start
-
1412 ((struct bpf_subprog_info
*)b
)->start
;
1415 static int find_subprog(struct bpf_verifier_env
*env
, int off
)
1417 struct bpf_subprog_info
*p
;
1419 p
= bsearch(&off
, env
->subprog_info
, env
->subprog_cnt
,
1420 sizeof(env
->subprog_info
[0]), cmp_subprogs
);
1423 return p
- env
->subprog_info
;
1427 static int add_subprog(struct bpf_verifier_env
*env
, int off
)
1429 int insn_cnt
= env
->prog
->len
;
1432 if (off
>= insn_cnt
|| off
< 0) {
1433 verbose(env
, "call to invalid destination\n");
1436 ret
= find_subprog(env
, off
);
1439 if (env
->subprog_cnt
>= BPF_MAX_SUBPROGS
) {
1440 verbose(env
, "too many subprograms\n");
1443 env
->subprog_info
[env
->subprog_cnt
++].start
= off
;
1444 sort(env
->subprog_info
, env
->subprog_cnt
,
1445 sizeof(env
->subprog_info
[0]), cmp_subprogs
, NULL
);
1449 static int check_subprogs(struct bpf_verifier_env
*env
)
1451 int i
, ret
, subprog_start
, subprog_end
, off
, cur_subprog
= 0;
1452 struct bpf_subprog_info
*subprog
= env
->subprog_info
;
1453 struct bpf_insn
*insn
= env
->prog
->insnsi
;
1454 int insn_cnt
= env
->prog
->len
;
1456 /* Add entry function. */
1457 ret
= add_subprog(env
, 0);
1461 /* determine subprog starts. The end is one before the next starts */
1462 for (i
= 0; i
< insn_cnt
; i
++) {
1463 if (insn
[i
].code
!= (BPF_JMP
| BPF_CALL
))
1465 if (insn
[i
].src_reg
!= BPF_PSEUDO_CALL
)
1467 if (!env
->bpf_capable
) {
1469 "function calls to other bpf functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n");
1472 ret
= add_subprog(env
, i
+ insn
[i
].imm
+ 1);
1477 /* Add a fake 'exit' subprog which could simplify subprog iteration
1478 * logic. 'subprog_cnt' should not be increased.
1480 subprog
[env
->subprog_cnt
].start
= insn_cnt
;
1482 if (env
->log
.level
& BPF_LOG_LEVEL2
)
1483 for (i
= 0; i
< env
->subprog_cnt
; i
++)
1484 verbose(env
, "func#%d @%d\n", i
, subprog
[i
].start
);
1486 /* now check that all jumps are within the same subprog */
1487 subprog_start
= subprog
[cur_subprog
].start
;
1488 subprog_end
= subprog
[cur_subprog
+ 1].start
;
1489 for (i
= 0; i
< insn_cnt
; i
++) {
1490 u8 code
= insn
[i
].code
;
1492 if (BPF_CLASS(code
) != BPF_JMP
&& BPF_CLASS(code
) != BPF_JMP32
)
1494 if (BPF_OP(code
) == BPF_EXIT
|| BPF_OP(code
) == BPF_CALL
)
1496 off
= i
+ insn
[i
].off
+ 1;
1497 if (off
< subprog_start
|| off
>= subprog_end
) {
1498 verbose(env
, "jump out of range from insn %d to %d\n", i
, off
);
1502 if (i
== subprog_end
- 1) {
1503 /* to avoid fall-through from one subprog into another
1504 * the last insn of the subprog should be either exit
1505 * or unconditional jump back
1507 if (code
!= (BPF_JMP
| BPF_EXIT
) &&
1508 code
!= (BPF_JMP
| BPF_JA
)) {
1509 verbose(env
, "last insn is not an exit or jmp\n");
1512 subprog_start
= subprog_end
;
1514 if (cur_subprog
< env
->subprog_cnt
)
1515 subprog_end
= subprog
[cur_subprog
+ 1].start
;
1521 /* Parentage chain of this register (or stack slot) should take care of all
1522 * issues like callee-saved registers, stack slot allocation time, etc.
1524 static int mark_reg_read(struct bpf_verifier_env
*env
,
1525 const struct bpf_reg_state
*state
,
1526 struct bpf_reg_state
*parent
, u8 flag
)
1528 bool writes
= parent
== state
->parent
; /* Observe write marks */
1532 /* if read wasn't screened by an earlier write ... */
1533 if (writes
&& state
->live
& REG_LIVE_WRITTEN
)
1535 if (parent
->live
& REG_LIVE_DONE
) {
1536 verbose(env
, "verifier BUG type %s var_off %lld off %d\n",
1537 reg_type_str
[parent
->type
],
1538 parent
->var_off
.value
, parent
->off
);
1541 /* The first condition is more likely to be true than the
1542 * second, checked it first.
1544 if ((parent
->live
& REG_LIVE_READ
) == flag
||
1545 parent
->live
& REG_LIVE_READ64
)
1546 /* The parentage chain never changes and
1547 * this parent was already marked as LIVE_READ.
1548 * There is no need to keep walking the chain again and
1549 * keep re-marking all parents as LIVE_READ.
1550 * This case happens when the same register is read
1551 * multiple times without writes into it in-between.
1552 * Also, if parent has the stronger REG_LIVE_READ64 set,
1553 * then no need to set the weak REG_LIVE_READ32.
1556 /* ... then we depend on parent's value */
1557 parent
->live
|= flag
;
1558 /* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
1559 if (flag
== REG_LIVE_READ64
)
1560 parent
->live
&= ~REG_LIVE_READ32
;
1562 parent
= state
->parent
;
1567 if (env
->longest_mark_read_walk
< cnt
)
1568 env
->longest_mark_read_walk
= cnt
;
1572 /* This function is supposed to be used by the following 32-bit optimization
1573 * code only. It returns TRUE if the source or destination register operates
1574 * on 64-bit, otherwise return FALSE.
1576 static bool is_reg64(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
,
1577 u32 regno
, struct bpf_reg_state
*reg
, enum reg_arg_type t
)
1582 class = BPF_CLASS(code
);
1584 if (class == BPF_JMP
) {
1585 /* BPF_EXIT for "main" will reach here. Return TRUE
1590 if (op
== BPF_CALL
) {
1591 /* BPF to BPF call will reach here because of marking
1592 * caller saved clobber with DST_OP_NO_MARK for which we
1593 * don't care the register def because they are anyway
1594 * marked as NOT_INIT already.
1596 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
1598 /* Helper call will reach here because of arg type
1599 * check, conservatively return TRUE.
1608 if (class == BPF_ALU64
|| class == BPF_JMP
||
1609 /* BPF_END always use BPF_ALU class. */
1610 (class == BPF_ALU
&& op
== BPF_END
&& insn
->imm
== 64))
1613 if (class == BPF_ALU
|| class == BPF_JMP32
)
1616 if (class == BPF_LDX
) {
1618 return BPF_SIZE(code
) == BPF_DW
;
1619 /* LDX source must be ptr. */
1623 if (class == BPF_STX
) {
1624 if (reg
->type
!= SCALAR_VALUE
)
1626 return BPF_SIZE(code
) == BPF_DW
;
1629 if (class == BPF_LD
) {
1630 u8 mode
= BPF_MODE(code
);
1633 if (mode
== BPF_IMM
)
1636 /* Both LD_IND and LD_ABS return 32-bit data. */
1640 /* Implicit ctx ptr. */
1641 if (regno
== BPF_REG_6
)
1644 /* Explicit source could be any width. */
1648 if (class == BPF_ST
)
1649 /* The only source register for BPF_ST is a ptr. */
1652 /* Conservatively return true at default. */
1656 /* Return TRUE if INSN doesn't have explicit value define. */
1657 static bool insn_no_def(struct bpf_insn
*insn
)
1659 u8
class = BPF_CLASS(insn
->code
);
1661 return (class == BPF_JMP
|| class == BPF_JMP32
||
1662 class == BPF_STX
|| class == BPF_ST
);
1665 /* Return TRUE if INSN has defined any 32-bit value explicitly. */
1666 static bool insn_has_def32(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
1668 if (insn_no_def(insn
))
1671 return !is_reg64(env
, insn
, insn
->dst_reg
, NULL
, DST_OP
);
1674 static void mark_insn_zext(struct bpf_verifier_env
*env
,
1675 struct bpf_reg_state
*reg
)
1677 s32 def_idx
= reg
->subreg_def
;
1679 if (def_idx
== DEF_NOT_SUBREG
)
1682 env
->insn_aux_data
[def_idx
- 1].zext_dst
= true;
1683 /* The dst will be zero extended, so won't be sub-register anymore. */
1684 reg
->subreg_def
= DEF_NOT_SUBREG
;
1687 static int check_reg_arg(struct bpf_verifier_env
*env
, u32 regno
,
1688 enum reg_arg_type t
)
1690 struct bpf_verifier_state
*vstate
= env
->cur_state
;
1691 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
1692 struct bpf_insn
*insn
= env
->prog
->insnsi
+ env
->insn_idx
;
1693 struct bpf_reg_state
*reg
, *regs
= state
->regs
;
1696 if (regno
>= MAX_BPF_REG
) {
1697 verbose(env
, "R%d is invalid\n", regno
);
1702 rw64
= is_reg64(env
, insn
, regno
, reg
, t
);
1704 /* check whether register used as source operand can be read */
1705 if (reg
->type
== NOT_INIT
) {
1706 verbose(env
, "R%d !read_ok\n", regno
);
1709 /* We don't need to worry about FP liveness because it's read-only */
1710 if (regno
== BPF_REG_FP
)
1714 mark_insn_zext(env
, reg
);
1716 return mark_reg_read(env
, reg
, reg
->parent
,
1717 rw64
? REG_LIVE_READ64
: REG_LIVE_READ32
);
1719 /* check whether register used as dest operand can be written to */
1720 if (regno
== BPF_REG_FP
) {
1721 verbose(env
, "frame pointer is read only\n");
1724 reg
->live
|= REG_LIVE_WRITTEN
;
1725 reg
->subreg_def
= rw64
? DEF_NOT_SUBREG
: env
->insn_idx
+ 1;
1727 mark_reg_unknown(env
, regs
, regno
);
1732 /* for any branch, call, exit record the history of jmps in the given state */
1733 static int push_jmp_history(struct bpf_verifier_env
*env
,
1734 struct bpf_verifier_state
*cur
)
1736 u32 cnt
= cur
->jmp_history_cnt
;
1737 struct bpf_idx_pair
*p
;
1740 p
= krealloc(cur
->jmp_history
, cnt
* sizeof(*p
), GFP_USER
);
1743 p
[cnt
- 1].idx
= env
->insn_idx
;
1744 p
[cnt
- 1].prev_idx
= env
->prev_insn_idx
;
1745 cur
->jmp_history
= p
;
1746 cur
->jmp_history_cnt
= cnt
;
1750 /* Backtrack one insn at a time. If idx is not at the top of recorded
1751 * history then previous instruction came from straight line execution.
1753 static int get_prev_insn_idx(struct bpf_verifier_state
*st
, int i
,
1758 if (cnt
&& st
->jmp_history
[cnt
- 1].idx
== i
) {
1759 i
= st
->jmp_history
[cnt
- 1].prev_idx
;
1767 /* For given verifier state backtrack_insn() is called from the last insn to
1768 * the first insn. Its purpose is to compute a bitmask of registers and
1769 * stack slots that needs precision in the parent verifier state.
1771 static int backtrack_insn(struct bpf_verifier_env
*env
, int idx
,
1772 u32
*reg_mask
, u64
*stack_mask
)
1774 const struct bpf_insn_cbs cbs
= {
1775 .cb_print
= verbose
,
1776 .private_data
= env
,
1778 struct bpf_insn
*insn
= env
->prog
->insnsi
+ idx
;
1779 u8
class = BPF_CLASS(insn
->code
);
1780 u8 opcode
= BPF_OP(insn
->code
);
1781 u8 mode
= BPF_MODE(insn
->code
);
1782 u32 dreg
= 1u << insn
->dst_reg
;
1783 u32 sreg
= 1u << insn
->src_reg
;
1786 if (insn
->code
== 0)
1788 if (env
->log
.level
& BPF_LOG_LEVEL
) {
1789 verbose(env
, "regs=%x stack=%llx before ", *reg_mask
, *stack_mask
);
1790 verbose(env
, "%d: ", idx
);
1791 print_bpf_insn(&cbs
, insn
, env
->allow_ptr_leaks
);
1794 if (class == BPF_ALU
|| class == BPF_ALU64
) {
1795 if (!(*reg_mask
& dreg
))
1797 if (opcode
== BPF_MOV
) {
1798 if (BPF_SRC(insn
->code
) == BPF_X
) {
1800 * dreg needs precision after this insn
1801 * sreg needs precision before this insn
1807 * dreg needs precision after this insn.
1808 * Corresponding register is already marked
1809 * as precise=true in this verifier state.
1810 * No further markings in parent are necessary
1815 if (BPF_SRC(insn
->code
) == BPF_X
) {
1817 * both dreg and sreg need precision
1822 * dreg still needs precision before this insn
1825 } else if (class == BPF_LDX
) {
1826 if (!(*reg_mask
& dreg
))
1830 /* scalars can only be spilled into stack w/o losing precision.
1831 * Load from any other memory can be zero extended.
1832 * The desire to keep that precision is already indicated
1833 * by 'precise' mark in corresponding register of this state.
1834 * No further tracking necessary.
1836 if (insn
->src_reg
!= BPF_REG_FP
)
1838 if (BPF_SIZE(insn
->code
) != BPF_DW
)
1841 /* dreg = *(u64 *)[fp - off] was a fill from the stack.
1842 * that [fp - off] slot contains scalar that needs to be
1843 * tracked with precision
1845 spi
= (-insn
->off
- 1) / BPF_REG_SIZE
;
1847 verbose(env
, "BUG spi %d\n", spi
);
1848 WARN_ONCE(1, "verifier backtracking bug");
1851 *stack_mask
|= 1ull << spi
;
1852 } else if (class == BPF_STX
|| class == BPF_ST
) {
1853 if (*reg_mask
& dreg
)
1854 /* stx & st shouldn't be using _scalar_ dst_reg
1855 * to access memory. It means backtracking
1856 * encountered a case of pointer subtraction.
1859 /* scalars can only be spilled into stack */
1860 if (insn
->dst_reg
!= BPF_REG_FP
)
1862 if (BPF_SIZE(insn
->code
) != BPF_DW
)
1864 spi
= (-insn
->off
- 1) / BPF_REG_SIZE
;
1866 verbose(env
, "BUG spi %d\n", spi
);
1867 WARN_ONCE(1, "verifier backtracking bug");
1870 if (!(*stack_mask
& (1ull << spi
)))
1872 *stack_mask
&= ~(1ull << spi
);
1873 if (class == BPF_STX
)
1875 } else if (class == BPF_JMP
|| class == BPF_JMP32
) {
1876 if (opcode
== BPF_CALL
) {
1877 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
1879 /* regular helper call sets R0 */
1881 if (*reg_mask
& 0x3f) {
1882 /* if backtracing was looking for registers R1-R5
1883 * they should have been found already.
1885 verbose(env
, "BUG regs %x\n", *reg_mask
);
1886 WARN_ONCE(1, "verifier backtracking bug");
1889 } else if (opcode
== BPF_EXIT
) {
1892 } else if (class == BPF_LD
) {
1893 if (!(*reg_mask
& dreg
))
1896 /* It's ld_imm64 or ld_abs or ld_ind.
1897 * For ld_imm64 no further tracking of precision
1898 * into parent is necessary
1900 if (mode
== BPF_IND
|| mode
== BPF_ABS
)
1901 /* to be analyzed */
1907 /* the scalar precision tracking algorithm:
1908 * . at the start all registers have precise=false.
1909 * . scalar ranges are tracked as normal through alu and jmp insns.
1910 * . once precise value of the scalar register is used in:
1911 * . ptr + scalar alu
1912 * . if (scalar cond K|scalar)
1913 * . helper_call(.., scalar, ...) where ARG_CONST is expected
1914 * backtrack through the verifier states and mark all registers and
1915 * stack slots with spilled constants that these scalar regisers
1916 * should be precise.
1917 * . during state pruning two registers (or spilled stack slots)
1918 * are equivalent if both are not precise.
1920 * Note the verifier cannot simply walk register parentage chain,
1921 * since many different registers and stack slots could have been
1922 * used to compute single precise scalar.
1924 * The approach of starting with precise=true for all registers and then
1925 * backtrack to mark a register as not precise when the verifier detects
1926 * that program doesn't care about specific value (e.g., when helper
1927 * takes register as ARG_ANYTHING parameter) is not safe.
1929 * It's ok to walk single parentage chain of the verifier states.
1930 * It's possible that this backtracking will go all the way till 1st insn.
1931 * All other branches will be explored for needing precision later.
1933 * The backtracking needs to deal with cases like:
1934 * 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)
1937 * if r5 > 0x79f goto pc+7
1938 * R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff))
1941 * call bpf_perf_event_output#25
1942 * where .arg5_type = ARG_CONST_SIZE_OR_ZERO
1946 * call foo // uses callee's r6 inside to compute r0
1950 * to track above reg_mask/stack_mask needs to be independent for each frame.
1952 * Also if parent's curframe > frame where backtracking started,
1953 * the verifier need to mark registers in both frames, otherwise callees
1954 * may incorrectly prune callers. This is similar to
1955 * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences")
1957 * For now backtracking falls back into conservative marking.
1959 static void mark_all_scalars_precise(struct bpf_verifier_env
*env
,
1960 struct bpf_verifier_state
*st
)
1962 struct bpf_func_state
*func
;
1963 struct bpf_reg_state
*reg
;
1966 /* big hammer: mark all scalars precise in this path.
1967 * pop_stack may still get !precise scalars.
1969 for (; st
; st
= st
->parent
)
1970 for (i
= 0; i
<= st
->curframe
; i
++) {
1971 func
= st
->frame
[i
];
1972 for (j
= 0; j
< BPF_REG_FP
; j
++) {
1973 reg
= &func
->regs
[j
];
1974 if (reg
->type
!= SCALAR_VALUE
)
1976 reg
->precise
= true;
1978 for (j
= 0; j
< func
->allocated_stack
/ BPF_REG_SIZE
; j
++) {
1979 if (func
->stack
[j
].slot_type
[0] != STACK_SPILL
)
1981 reg
= &func
->stack
[j
].spilled_ptr
;
1982 if (reg
->type
!= SCALAR_VALUE
)
1984 reg
->precise
= true;
1989 static int __mark_chain_precision(struct bpf_verifier_env
*env
, int regno
,
1992 struct bpf_verifier_state
*st
= env
->cur_state
;
1993 int first_idx
= st
->first_insn_idx
;
1994 int last_idx
= env
->insn_idx
;
1995 struct bpf_func_state
*func
;
1996 struct bpf_reg_state
*reg
;
1997 u32 reg_mask
= regno
>= 0 ? 1u << regno
: 0;
1998 u64 stack_mask
= spi
>= 0 ? 1ull << spi
: 0;
1999 bool skip_first
= true;
2000 bool new_marks
= false;
2003 if (!env
->bpf_capable
)
2006 func
= st
->frame
[st
->curframe
];
2008 reg
= &func
->regs
[regno
];
2009 if (reg
->type
!= SCALAR_VALUE
) {
2010 WARN_ONCE(1, "backtracing misuse");
2017 reg
->precise
= true;
2021 if (func
->stack
[spi
].slot_type
[0] != STACK_SPILL
) {
2025 reg
= &func
->stack
[spi
].spilled_ptr
;
2026 if (reg
->type
!= SCALAR_VALUE
) {
2034 reg
->precise
= true;
2040 if (!reg_mask
&& !stack_mask
)
2043 DECLARE_BITMAP(mask
, 64);
2044 u32 history
= st
->jmp_history_cnt
;
2046 if (env
->log
.level
& BPF_LOG_LEVEL
)
2047 verbose(env
, "last_idx %d first_idx %d\n", last_idx
, first_idx
);
2048 for (i
= last_idx
;;) {
2053 err
= backtrack_insn(env
, i
, ®_mask
, &stack_mask
);
2055 if (err
== -ENOTSUPP
) {
2056 mark_all_scalars_precise(env
, st
);
2061 if (!reg_mask
&& !stack_mask
)
2062 /* Found assignment(s) into tracked register in this state.
2063 * Since this state is already marked, just return.
2064 * Nothing to be tracked further in the parent state.
2069 i
= get_prev_insn_idx(st
, i
, &history
);
2070 if (i
>= env
->prog
->len
) {
2071 /* This can happen if backtracking reached insn 0
2072 * and there are still reg_mask or stack_mask
2074 * It means the backtracking missed the spot where
2075 * particular register was initialized with a constant.
2077 verbose(env
, "BUG backtracking idx %d\n", i
);
2078 WARN_ONCE(1, "verifier backtracking bug");
2087 func
= st
->frame
[st
->curframe
];
2088 bitmap_from_u64(mask
, reg_mask
);
2089 for_each_set_bit(i
, mask
, 32) {
2090 reg
= &func
->regs
[i
];
2091 if (reg
->type
!= SCALAR_VALUE
) {
2092 reg_mask
&= ~(1u << i
);
2097 reg
->precise
= true;
2100 bitmap_from_u64(mask
, stack_mask
);
2101 for_each_set_bit(i
, mask
, 64) {
2102 if (i
>= func
->allocated_stack
/ BPF_REG_SIZE
) {
2103 /* the sequence of instructions:
2105 * 3: (7b) *(u64 *)(r3 -8) = r0
2106 * 4: (79) r4 = *(u64 *)(r10 -8)
2107 * doesn't contain jmps. It's backtracked
2108 * as a single block.
2109 * During backtracking insn 3 is not recognized as
2110 * stack access, so at the end of backtracking
2111 * stack slot fp-8 is still marked in stack_mask.
2112 * However the parent state may not have accessed
2113 * fp-8 and it's "unallocated" stack space.
2114 * In such case fallback to conservative.
2116 mark_all_scalars_precise(env
, st
);
2120 if (func
->stack
[i
].slot_type
[0] != STACK_SPILL
) {
2121 stack_mask
&= ~(1ull << i
);
2124 reg
= &func
->stack
[i
].spilled_ptr
;
2125 if (reg
->type
!= SCALAR_VALUE
) {
2126 stack_mask
&= ~(1ull << i
);
2131 reg
->precise
= true;
2133 if (env
->log
.level
& BPF_LOG_LEVEL
) {
2134 print_verifier_state(env
, func
);
2135 verbose(env
, "parent %s regs=%x stack=%llx marks\n",
2136 new_marks
? "didn't have" : "already had",
2137 reg_mask
, stack_mask
);
2140 if (!reg_mask
&& !stack_mask
)
2145 last_idx
= st
->last_insn_idx
;
2146 first_idx
= st
->first_insn_idx
;
2151 static int mark_chain_precision(struct bpf_verifier_env
*env
, int regno
)
2153 return __mark_chain_precision(env
, regno
, -1);
2156 static int mark_chain_precision_stack(struct bpf_verifier_env
*env
, int spi
)
2158 return __mark_chain_precision(env
, -1, spi
);
2161 static bool is_spillable_regtype(enum bpf_reg_type type
)
2164 case PTR_TO_MAP_VALUE
:
2165 case PTR_TO_MAP_VALUE_OR_NULL
:
2169 case PTR_TO_PACKET_META
:
2170 case PTR_TO_PACKET_END
:
2171 case PTR_TO_FLOW_KEYS
:
2172 case CONST_PTR_TO_MAP
:
2174 case PTR_TO_SOCKET_OR_NULL
:
2175 case PTR_TO_SOCK_COMMON
:
2176 case PTR_TO_SOCK_COMMON_OR_NULL
:
2177 case PTR_TO_TCP_SOCK
:
2178 case PTR_TO_TCP_SOCK_OR_NULL
:
2179 case PTR_TO_XDP_SOCK
:
2181 case PTR_TO_BTF_ID_OR_NULL
:
2182 case PTR_TO_RDONLY_BUF
:
2183 case PTR_TO_RDONLY_BUF_OR_NULL
:
2184 case PTR_TO_RDWR_BUF
:
2185 case PTR_TO_RDWR_BUF_OR_NULL
:
2192 /* Does this register contain a constant zero? */
2193 static bool register_is_null(struct bpf_reg_state
*reg
)
2195 return reg
->type
== SCALAR_VALUE
&& tnum_equals_const(reg
->var_off
, 0);
2198 static bool register_is_const(struct bpf_reg_state
*reg
)
2200 return reg
->type
== SCALAR_VALUE
&& tnum_is_const(reg
->var_off
);
2203 static bool __is_pointer_value(bool allow_ptr_leaks
,
2204 const struct bpf_reg_state
*reg
)
2206 if (allow_ptr_leaks
)
2209 return reg
->type
!= SCALAR_VALUE
;
2212 static void save_register_state(struct bpf_func_state
*state
,
2213 int spi
, struct bpf_reg_state
*reg
)
2217 state
->stack
[spi
].spilled_ptr
= *reg
;
2218 state
->stack
[spi
].spilled_ptr
.live
|= REG_LIVE_WRITTEN
;
2220 for (i
= 0; i
< BPF_REG_SIZE
; i
++)
2221 state
->stack
[spi
].slot_type
[i
] = STACK_SPILL
;
2224 /* check_stack_read/write functions track spill/fill of registers,
2225 * stack boundary and alignment are checked in check_mem_access()
2227 static int check_stack_write(struct bpf_verifier_env
*env
,
2228 struct bpf_func_state
*state
, /* func where register points to */
2229 int off
, int size
, int value_regno
, int insn_idx
)
2231 struct bpf_func_state
*cur
; /* state of the current function */
2232 int i
, slot
= -off
- 1, spi
= slot
/ BPF_REG_SIZE
, err
;
2233 u32 dst_reg
= env
->prog
->insnsi
[insn_idx
].dst_reg
;
2234 struct bpf_reg_state
*reg
= NULL
;
2236 err
= realloc_func_state(state
, round_up(slot
+ 1, BPF_REG_SIZE
),
2237 state
->acquired_refs
, true);
2240 /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
2241 * so it's aligned access and [off, off + size) are within stack limits
2243 if (!env
->allow_ptr_leaks
&&
2244 state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
2245 size
!= BPF_REG_SIZE
) {
2246 verbose(env
, "attempt to corrupt spilled pointer on stack\n");
2250 cur
= env
->cur_state
->frame
[env
->cur_state
->curframe
];
2251 if (value_regno
>= 0)
2252 reg
= &cur
->regs
[value_regno
];
2254 if (reg
&& size
== BPF_REG_SIZE
&& register_is_const(reg
) &&
2255 !register_is_null(reg
) && env
->bpf_capable
) {
2256 if (dst_reg
!= BPF_REG_FP
) {
2257 /* The backtracking logic can only recognize explicit
2258 * stack slot address like [fp - 8]. Other spill of
2259 * scalar via different register has to be conervative.
2260 * Backtrack from here and mark all registers as precise
2261 * that contributed into 'reg' being a constant.
2263 err
= mark_chain_precision(env
, value_regno
);
2267 save_register_state(state
, spi
, reg
);
2268 } else if (reg
&& is_spillable_regtype(reg
->type
)) {
2269 /* register containing pointer is being spilled into stack */
2270 if (size
!= BPF_REG_SIZE
) {
2271 verbose_linfo(env
, insn_idx
, "; ");
2272 verbose(env
, "invalid size of register spill\n");
2276 if (state
!= cur
&& reg
->type
== PTR_TO_STACK
) {
2277 verbose(env
, "cannot spill pointers to stack into stack frame of the caller\n");
2281 if (!env
->bypass_spec_v4
) {
2282 bool sanitize
= false;
2284 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
2285 register_is_const(&state
->stack
[spi
].spilled_ptr
))
2287 for (i
= 0; i
< BPF_REG_SIZE
; i
++)
2288 if (state
->stack
[spi
].slot_type
[i
] == STACK_MISC
) {
2293 int *poff
= &env
->insn_aux_data
[insn_idx
].sanitize_stack_off
;
2294 int soff
= (-spi
- 1) * BPF_REG_SIZE
;
2296 /* detected reuse of integer stack slot with a pointer
2297 * which means either llvm is reusing stack slot or
2298 * an attacker is trying to exploit CVE-2018-3639
2299 * (speculative store bypass)
2300 * Have to sanitize that slot with preemptive
2303 if (*poff
&& *poff
!= soff
) {
2304 /* disallow programs where single insn stores
2305 * into two different stack slots, since verifier
2306 * cannot sanitize them
2309 "insn %d cannot access two stack slots fp%d and fp%d",
2310 insn_idx
, *poff
, soff
);
2316 save_register_state(state
, spi
, reg
);
2318 u8 type
= STACK_MISC
;
2320 /* regular write of data into stack destroys any spilled ptr */
2321 state
->stack
[spi
].spilled_ptr
.type
= NOT_INIT
;
2322 /* Mark slots as STACK_MISC if they belonged to spilled ptr. */
2323 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
)
2324 for (i
= 0; i
< BPF_REG_SIZE
; i
++)
2325 state
->stack
[spi
].slot_type
[i
] = STACK_MISC
;
2327 /* only mark the slot as written if all 8 bytes were written
2328 * otherwise read propagation may incorrectly stop too soon
2329 * when stack slots are partially written.
2330 * This heuristic means that read propagation will be
2331 * conservative, since it will add reg_live_read marks
2332 * to stack slots all the way to first state when programs
2333 * writes+reads less than 8 bytes
2335 if (size
== BPF_REG_SIZE
)
2336 state
->stack
[spi
].spilled_ptr
.live
|= REG_LIVE_WRITTEN
;
2338 /* when we zero initialize stack slots mark them as such */
2339 if (reg
&& register_is_null(reg
)) {
2340 /* backtracking doesn't work for STACK_ZERO yet. */
2341 err
= mark_chain_precision(env
, value_regno
);
2347 /* Mark slots affected by this stack write. */
2348 for (i
= 0; i
< size
; i
++)
2349 state
->stack
[spi
].slot_type
[(slot
- i
) % BPF_REG_SIZE
] =
2355 static int check_stack_read(struct bpf_verifier_env
*env
,
2356 struct bpf_func_state
*reg_state
/* func where register points to */,
2357 int off
, int size
, int value_regno
)
2359 struct bpf_verifier_state
*vstate
= env
->cur_state
;
2360 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
2361 int i
, slot
= -off
- 1, spi
= slot
/ BPF_REG_SIZE
;
2362 struct bpf_reg_state
*reg
;
2365 if (reg_state
->allocated_stack
<= slot
) {
2366 verbose(env
, "invalid read from stack off %d+0 size %d\n",
2370 stype
= reg_state
->stack
[spi
].slot_type
;
2371 reg
= ®_state
->stack
[spi
].spilled_ptr
;
2373 if (stype
[0] == STACK_SPILL
) {
2374 if (size
!= BPF_REG_SIZE
) {
2375 if (reg
->type
!= SCALAR_VALUE
) {
2376 verbose_linfo(env
, env
->insn_idx
, "; ");
2377 verbose(env
, "invalid size of register fill\n");
2380 if (value_regno
>= 0) {
2381 mark_reg_unknown(env
, state
->regs
, value_regno
);
2382 state
->regs
[value_regno
].live
|= REG_LIVE_WRITTEN
;
2384 mark_reg_read(env
, reg
, reg
->parent
, REG_LIVE_READ64
);
2387 for (i
= 1; i
< BPF_REG_SIZE
; i
++) {
2388 if (stype
[(slot
- i
) % BPF_REG_SIZE
] != STACK_SPILL
) {
2389 verbose(env
, "corrupted spill memory\n");
2394 if (value_regno
>= 0) {
2395 /* restore register state from stack */
2396 state
->regs
[value_regno
] = *reg
;
2397 /* mark reg as written since spilled pointer state likely
2398 * has its liveness marks cleared by is_state_visited()
2399 * which resets stack/reg liveness for state transitions
2401 state
->regs
[value_regno
].live
|= REG_LIVE_WRITTEN
;
2402 } else if (__is_pointer_value(env
->allow_ptr_leaks
, reg
)) {
2403 /* If value_regno==-1, the caller is asking us whether
2404 * it is acceptable to use this value as a SCALAR_VALUE
2406 * We must not allow unprivileged callers to do that
2407 * with spilled pointers.
2409 verbose(env
, "leaking pointer from stack off %d\n",
2413 mark_reg_read(env
, reg
, reg
->parent
, REG_LIVE_READ64
);
2417 for (i
= 0; i
< size
; i
++) {
2418 if (stype
[(slot
- i
) % BPF_REG_SIZE
] == STACK_MISC
)
2420 if (stype
[(slot
- i
) % BPF_REG_SIZE
] == STACK_ZERO
) {
2424 verbose(env
, "invalid read from stack off %d+%d size %d\n",
2428 mark_reg_read(env
, reg
, reg
->parent
, REG_LIVE_READ64
);
2429 if (value_regno
>= 0) {
2430 if (zeros
== size
) {
2431 /* any size read into register is zero extended,
2432 * so the whole register == const_zero
2434 __mark_reg_const_zero(&state
->regs
[value_regno
]);
2435 /* backtracking doesn't support STACK_ZERO yet,
2436 * so mark it precise here, so that later
2437 * backtracking can stop here.
2438 * Backtracking may not need this if this register
2439 * doesn't participate in pointer adjustment.
2440 * Forward propagation of precise flag is not
2441 * necessary either. This mark is only to stop
2442 * backtracking. Any register that contributed
2443 * to const 0 was marked precise before spill.
2445 state
->regs
[value_regno
].precise
= true;
2447 /* have read misc data from the stack */
2448 mark_reg_unknown(env
, state
->regs
, value_regno
);
2450 state
->regs
[value_regno
].live
|= REG_LIVE_WRITTEN
;
2456 static int check_stack_access(struct bpf_verifier_env
*env
,
2457 const struct bpf_reg_state
*reg
,
2460 /* Stack accesses must be at a fixed offset, so that we
2461 * can determine what type of data were returned. See
2462 * check_stack_read().
2464 if (!tnum_is_const(reg
->var_off
)) {
2467 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
2468 verbose(env
, "variable stack access var_off=%s off=%d size=%d\n",
2473 if (off
>= 0 || off
< -MAX_BPF_STACK
) {
2474 verbose(env
, "invalid stack off=%d size=%d\n", off
, size
);
2481 static int check_map_access_type(struct bpf_verifier_env
*env
, u32 regno
,
2482 int off
, int size
, enum bpf_access_type type
)
2484 struct bpf_reg_state
*regs
= cur_regs(env
);
2485 struct bpf_map
*map
= regs
[regno
].map_ptr
;
2486 u32 cap
= bpf_map_flags_to_cap(map
);
2488 if (type
== BPF_WRITE
&& !(cap
& BPF_MAP_CAN_WRITE
)) {
2489 verbose(env
, "write into map forbidden, value_size=%d off=%d size=%d\n",
2490 map
->value_size
, off
, size
);
2494 if (type
== BPF_READ
&& !(cap
& BPF_MAP_CAN_READ
)) {
2495 verbose(env
, "read from map forbidden, value_size=%d off=%d size=%d\n",
2496 map
->value_size
, off
, size
);
2503 /* check read/write into memory region (e.g., map value, ringbuf sample, etc) */
2504 static int __check_mem_access(struct bpf_verifier_env
*env
, int regno
,
2505 int off
, int size
, u32 mem_size
,
2506 bool zero_size_allowed
)
2508 bool size_ok
= size
> 0 || (size
== 0 && zero_size_allowed
);
2509 struct bpf_reg_state
*reg
;
2511 if (off
>= 0 && size_ok
&& (u64
)off
+ size
<= mem_size
)
2514 reg
= &cur_regs(env
)[regno
];
2515 switch (reg
->type
) {
2516 case PTR_TO_MAP_VALUE
:
2517 verbose(env
, "invalid access to map value, value_size=%d off=%d size=%d\n",
2518 mem_size
, off
, size
);
2521 case PTR_TO_PACKET_META
:
2522 case PTR_TO_PACKET_END
:
2523 verbose(env
, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
2524 off
, size
, regno
, reg
->id
, off
, mem_size
);
2528 verbose(env
, "invalid access to memory, mem_size=%u off=%d size=%d\n",
2529 mem_size
, off
, size
);
2535 /* check read/write into a memory region with possible variable offset */
2536 static int check_mem_region_access(struct bpf_verifier_env
*env
, u32 regno
,
2537 int off
, int size
, u32 mem_size
,
2538 bool zero_size_allowed
)
2540 struct bpf_verifier_state
*vstate
= env
->cur_state
;
2541 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
2542 struct bpf_reg_state
*reg
= &state
->regs
[regno
];
2545 /* We may have adjusted the register pointing to memory region, so we
2546 * need to try adding each of min_value and max_value to off
2547 * to make sure our theoretical access will be safe.
2549 if (env
->log
.level
& BPF_LOG_LEVEL
)
2550 print_verifier_state(env
, state
);
2552 /* The minimum value is only important with signed
2553 * comparisons where we can't assume the floor of a
2554 * value is 0. If we are using signed variables for our
2555 * index'es we need to make sure that whatever we use
2556 * will have a set floor within our range.
2558 if (reg
->smin_value
< 0 &&
2559 (reg
->smin_value
== S64_MIN
||
2560 (off
+ reg
->smin_value
!= (s64
)(s32
)(off
+ reg
->smin_value
)) ||
2561 reg
->smin_value
+ off
< 0)) {
2562 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
2566 err
= __check_mem_access(env
, regno
, reg
->smin_value
+ off
, size
,
2567 mem_size
, zero_size_allowed
);
2569 verbose(env
, "R%d min value is outside of the allowed memory range\n",
2574 /* If we haven't set a max value then we need to bail since we can't be
2575 * sure we won't do bad things.
2576 * If reg->umax_value + off could overflow, treat that as unbounded too.
2578 if (reg
->umax_value
>= BPF_MAX_VAR_OFF
) {
2579 verbose(env
, "R%d unbounded memory access, make sure to bounds check any such access\n",
2583 err
= __check_mem_access(env
, regno
, reg
->umax_value
+ off
, size
,
2584 mem_size
, zero_size_allowed
);
2586 verbose(env
, "R%d max value is outside of the allowed memory range\n",
2594 /* check read/write into a map element with possible variable offset */
2595 static int check_map_access(struct bpf_verifier_env
*env
, u32 regno
,
2596 int off
, int size
, bool zero_size_allowed
)
2598 struct bpf_verifier_state
*vstate
= env
->cur_state
;
2599 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
2600 struct bpf_reg_state
*reg
= &state
->regs
[regno
];
2601 struct bpf_map
*map
= reg
->map_ptr
;
2604 err
= check_mem_region_access(env
, regno
, off
, size
, map
->value_size
,
2609 if (map_value_has_spin_lock(map
)) {
2610 u32 lock
= map
->spin_lock_off
;
2612 /* if any part of struct bpf_spin_lock can be touched by
2613 * load/store reject this program.
2614 * To check that [x1, x2) overlaps with [y1, y2)
2615 * it is sufficient to check x1 < y2 && y1 < x2.
2617 if (reg
->smin_value
+ off
< lock
+ sizeof(struct bpf_spin_lock
) &&
2618 lock
< reg
->umax_value
+ off
+ size
) {
2619 verbose(env
, "bpf_spin_lock cannot be accessed directly by load/store\n");
2626 #define MAX_PACKET_OFF 0xffff
2628 static bool may_access_direct_pkt_data(struct bpf_verifier_env
*env
,
2629 const struct bpf_call_arg_meta
*meta
,
2630 enum bpf_access_type t
)
2632 switch (env
->prog
->type
) {
2633 /* Program types only with direct read access go here! */
2634 case BPF_PROG_TYPE_LWT_IN
:
2635 case BPF_PROG_TYPE_LWT_OUT
:
2636 case BPF_PROG_TYPE_LWT_SEG6LOCAL
:
2637 case BPF_PROG_TYPE_SK_REUSEPORT
:
2638 case BPF_PROG_TYPE_FLOW_DISSECTOR
:
2639 case BPF_PROG_TYPE_CGROUP_SKB
:
2644 /* Program types with direct read + write access go here! */
2645 case BPF_PROG_TYPE_SCHED_CLS
:
2646 case BPF_PROG_TYPE_SCHED_ACT
:
2647 case BPF_PROG_TYPE_XDP
:
2648 case BPF_PROG_TYPE_LWT_XMIT
:
2649 case BPF_PROG_TYPE_SK_SKB
:
2650 case BPF_PROG_TYPE_SK_MSG
:
2652 return meta
->pkt_access
;
2654 env
->seen_direct_write
= true;
2657 case BPF_PROG_TYPE_CGROUP_SOCKOPT
:
2659 env
->seen_direct_write
= true;
2668 static int check_packet_access(struct bpf_verifier_env
*env
, u32 regno
, int off
,
2669 int size
, bool zero_size_allowed
)
2671 struct bpf_reg_state
*regs
= cur_regs(env
);
2672 struct bpf_reg_state
*reg
= ®s
[regno
];
2675 /* We may have added a variable offset to the packet pointer; but any
2676 * reg->range we have comes after that. We are only checking the fixed
2680 /* We don't allow negative numbers, because we aren't tracking enough
2681 * detail to prove they're safe.
2683 if (reg
->smin_value
< 0) {
2684 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
2688 err
= __check_mem_access(env
, regno
, off
, size
, reg
->range
,
2691 verbose(env
, "R%d offset is outside of the packet\n", regno
);
2695 /* __check_mem_access has made sure "off + size - 1" is within u16.
2696 * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
2697 * otherwise find_good_pkt_pointers would have refused to set range info
2698 * that __check_mem_access would have rejected this pkt access.
2699 * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
2701 env
->prog
->aux
->max_pkt_offset
=
2702 max_t(u32
, env
->prog
->aux
->max_pkt_offset
,
2703 off
+ reg
->umax_value
+ size
- 1);
2708 /* check access to 'struct bpf_context' fields. Supports fixed offsets only */
2709 static int check_ctx_access(struct bpf_verifier_env
*env
, int insn_idx
, int off
, int size
,
2710 enum bpf_access_type t
, enum bpf_reg_type
*reg_type
,
2713 struct bpf_insn_access_aux info
= {
2714 .reg_type
= *reg_type
,
2718 if (env
->ops
->is_valid_access
&&
2719 env
->ops
->is_valid_access(off
, size
, t
, env
->prog
, &info
)) {
2720 /* A non zero info.ctx_field_size indicates that this field is a
2721 * candidate for later verifier transformation to load the whole
2722 * field and then apply a mask when accessed with a narrower
2723 * access than actual ctx access size. A zero info.ctx_field_size
2724 * will only allow for whole field access and rejects any other
2725 * type of narrower access.
2727 *reg_type
= info
.reg_type
;
2729 if (*reg_type
== PTR_TO_BTF_ID
|| *reg_type
== PTR_TO_BTF_ID_OR_NULL
)
2730 *btf_id
= info
.btf_id
;
2732 env
->insn_aux_data
[insn_idx
].ctx_field_size
= info
.ctx_field_size
;
2733 /* remember the offset of last byte accessed in ctx */
2734 if (env
->prog
->aux
->max_ctx_offset
< off
+ size
)
2735 env
->prog
->aux
->max_ctx_offset
= off
+ size
;
2739 verbose(env
, "invalid bpf_context access off=%d size=%d\n", off
, size
);
2743 static int check_flow_keys_access(struct bpf_verifier_env
*env
, int off
,
2746 if (size
< 0 || off
< 0 ||
2747 (u64
)off
+ size
> sizeof(struct bpf_flow_keys
)) {
2748 verbose(env
, "invalid access to flow keys off=%d size=%d\n",
2755 static int check_sock_access(struct bpf_verifier_env
*env
, int insn_idx
,
2756 u32 regno
, int off
, int size
,
2757 enum bpf_access_type t
)
2759 struct bpf_reg_state
*regs
= cur_regs(env
);
2760 struct bpf_reg_state
*reg
= ®s
[regno
];
2761 struct bpf_insn_access_aux info
= {};
2764 if (reg
->smin_value
< 0) {
2765 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
2770 switch (reg
->type
) {
2771 case PTR_TO_SOCK_COMMON
:
2772 valid
= bpf_sock_common_is_valid_access(off
, size
, t
, &info
);
2775 valid
= bpf_sock_is_valid_access(off
, size
, t
, &info
);
2777 case PTR_TO_TCP_SOCK
:
2778 valid
= bpf_tcp_sock_is_valid_access(off
, size
, t
, &info
);
2780 case PTR_TO_XDP_SOCK
:
2781 valid
= bpf_xdp_sock_is_valid_access(off
, size
, t
, &info
);
2789 env
->insn_aux_data
[insn_idx
].ctx_field_size
=
2790 info
.ctx_field_size
;
2794 verbose(env
, "R%d invalid %s access off=%d size=%d\n",
2795 regno
, reg_type_str
[reg
->type
], off
, size
);
2800 static struct bpf_reg_state
*reg_state(struct bpf_verifier_env
*env
, int regno
)
2802 return cur_regs(env
) + regno
;
2805 static bool is_pointer_value(struct bpf_verifier_env
*env
, int regno
)
2807 return __is_pointer_value(env
->allow_ptr_leaks
, reg_state(env
, regno
));
2810 static bool is_ctx_reg(struct bpf_verifier_env
*env
, int regno
)
2812 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
2814 return reg
->type
== PTR_TO_CTX
;
2817 static bool is_sk_reg(struct bpf_verifier_env
*env
, int regno
)
2819 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
2821 return type_is_sk_pointer(reg
->type
);
2824 static bool is_pkt_reg(struct bpf_verifier_env
*env
, int regno
)
2826 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
2828 return type_is_pkt_pointer(reg
->type
);
2831 static bool is_flow_key_reg(struct bpf_verifier_env
*env
, int regno
)
2833 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
2835 /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
2836 return reg
->type
== PTR_TO_FLOW_KEYS
;
2839 static int check_pkt_ptr_alignment(struct bpf_verifier_env
*env
,
2840 const struct bpf_reg_state
*reg
,
2841 int off
, int size
, bool strict
)
2843 struct tnum reg_off
;
2846 /* Byte size accesses are always allowed. */
2847 if (!strict
|| size
== 1)
2850 /* For platforms that do not have a Kconfig enabling
2851 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
2852 * NET_IP_ALIGN is universally set to '2'. And on platforms
2853 * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
2854 * to this code only in strict mode where we want to emulate
2855 * the NET_IP_ALIGN==2 checking. Therefore use an
2856 * unconditional IP align value of '2'.
2860 reg_off
= tnum_add(reg
->var_off
, tnum_const(ip_align
+ reg
->off
+ off
));
2861 if (!tnum_is_aligned(reg_off
, size
)) {
2864 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
2866 "misaligned packet access off %d+%s+%d+%d size %d\n",
2867 ip_align
, tn_buf
, reg
->off
, off
, size
);
2874 static int check_generic_ptr_alignment(struct bpf_verifier_env
*env
,
2875 const struct bpf_reg_state
*reg
,
2876 const char *pointer_desc
,
2877 int off
, int size
, bool strict
)
2879 struct tnum reg_off
;
2881 /* Byte size accesses are always allowed. */
2882 if (!strict
|| size
== 1)
2885 reg_off
= tnum_add(reg
->var_off
, tnum_const(reg
->off
+ off
));
2886 if (!tnum_is_aligned(reg_off
, size
)) {
2889 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
2890 verbose(env
, "misaligned %saccess off %s+%d+%d size %d\n",
2891 pointer_desc
, tn_buf
, reg
->off
, off
, size
);
2898 static int check_ptr_alignment(struct bpf_verifier_env
*env
,
2899 const struct bpf_reg_state
*reg
, int off
,
2900 int size
, bool strict_alignment_once
)
2902 bool strict
= env
->strict_alignment
|| strict_alignment_once
;
2903 const char *pointer_desc
= "";
2905 switch (reg
->type
) {
2907 case PTR_TO_PACKET_META
:
2908 /* Special case, because of NET_IP_ALIGN. Given metadata sits
2909 * right in front, treat it the very same way.
2911 return check_pkt_ptr_alignment(env
, reg
, off
, size
, strict
);
2912 case PTR_TO_FLOW_KEYS
:
2913 pointer_desc
= "flow keys ";
2915 case PTR_TO_MAP_VALUE
:
2916 pointer_desc
= "value ";
2919 pointer_desc
= "context ";
2922 pointer_desc
= "stack ";
2923 /* The stack spill tracking logic in check_stack_write()
2924 * and check_stack_read() relies on stack accesses being
2930 pointer_desc
= "sock ";
2932 case PTR_TO_SOCK_COMMON
:
2933 pointer_desc
= "sock_common ";
2935 case PTR_TO_TCP_SOCK
:
2936 pointer_desc
= "tcp_sock ";
2938 case PTR_TO_XDP_SOCK
:
2939 pointer_desc
= "xdp_sock ";
2944 return check_generic_ptr_alignment(env
, reg
, pointer_desc
, off
, size
,
2948 static int update_stack_depth(struct bpf_verifier_env
*env
,
2949 const struct bpf_func_state
*func
,
2952 u16 stack
= env
->subprog_info
[func
->subprogno
].stack_depth
;
2957 /* update known max for given subprogram */
2958 env
->subprog_info
[func
->subprogno
].stack_depth
= -off
;
2962 /* starting from main bpf function walk all instructions of the function
2963 * and recursively walk all callees that given function can call.
2964 * Ignore jump and exit insns.
2965 * Since recursion is prevented by check_cfg() this algorithm
2966 * only needs a local stack of MAX_CALL_FRAMES to remember callsites
2968 static int check_max_stack_depth(struct bpf_verifier_env
*env
)
2970 int depth
= 0, frame
= 0, idx
= 0, i
= 0, subprog_end
;
2971 struct bpf_subprog_info
*subprog
= env
->subprog_info
;
2972 struct bpf_insn
*insn
= env
->prog
->insnsi
;
2973 int ret_insn
[MAX_CALL_FRAMES
];
2974 int ret_prog
[MAX_CALL_FRAMES
];
2977 /* round up to 32-bytes, since this is granularity
2978 * of interpreter stack size
2980 depth
+= round_up(max_t(u32
, subprog
[idx
].stack_depth
, 1), 32);
2981 if (depth
> MAX_BPF_STACK
) {
2982 verbose(env
, "combined stack size of %d calls is %d. Too large\n",
2987 subprog_end
= subprog
[idx
+ 1].start
;
2988 for (; i
< subprog_end
; i
++) {
2989 if (insn
[i
].code
!= (BPF_JMP
| BPF_CALL
))
2991 if (insn
[i
].src_reg
!= BPF_PSEUDO_CALL
)
2993 /* remember insn and function to return to */
2994 ret_insn
[frame
] = i
+ 1;
2995 ret_prog
[frame
] = idx
;
2997 /* find the callee */
2998 i
= i
+ insn
[i
].imm
+ 1;
2999 idx
= find_subprog(env
, i
);
3001 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
3006 if (frame
>= MAX_CALL_FRAMES
) {
3007 verbose(env
, "the call stack of %d frames is too deep !\n",
3013 /* end of for() loop means the last insn of the 'subprog'
3014 * was reached. Doesn't matter whether it was JA or EXIT
3018 depth
-= round_up(max_t(u32
, subprog
[idx
].stack_depth
, 1), 32);
3020 i
= ret_insn
[frame
];
3021 idx
= ret_prog
[frame
];
3025 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
3026 static int get_callee_stack_depth(struct bpf_verifier_env
*env
,
3027 const struct bpf_insn
*insn
, int idx
)
3029 int start
= idx
+ insn
->imm
+ 1, subprog
;
3031 subprog
= find_subprog(env
, start
);
3033 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
3037 return env
->subprog_info
[subprog
].stack_depth
;
3041 int check_ctx_reg(struct bpf_verifier_env
*env
,
3042 const struct bpf_reg_state
*reg
, int regno
)
3044 /* Access to ctx or passing it to a helper is only allowed in
3045 * its original, unmodified form.
3049 verbose(env
, "dereference of modified ctx ptr R%d off=%d disallowed\n",
3054 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
3057 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3058 verbose(env
, "variable ctx access var_off=%s disallowed\n", tn_buf
);
3065 static int __check_buffer_access(struct bpf_verifier_env
*env
,
3066 const char *buf_info
,
3067 const struct bpf_reg_state
*reg
,
3068 int regno
, int off
, int size
)
3072 "R%d invalid %s buffer access: off=%d, size=%d",
3073 regno
, buf_info
, off
, size
);
3076 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
3079 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3081 "R%d invalid variable buffer offset: off=%d, var_off=%s",
3082 regno
, off
, tn_buf
);
3089 static int check_tp_buffer_access(struct bpf_verifier_env
*env
,
3090 const struct bpf_reg_state
*reg
,
3091 int regno
, int off
, int size
)
3095 err
= __check_buffer_access(env
, "tracepoint", reg
, regno
, off
, size
);
3099 if (off
+ size
> env
->prog
->aux
->max_tp_access
)
3100 env
->prog
->aux
->max_tp_access
= off
+ size
;
3105 static int check_buffer_access(struct bpf_verifier_env
*env
,
3106 const struct bpf_reg_state
*reg
,
3107 int regno
, int off
, int size
,
3108 bool zero_size_allowed
,
3109 const char *buf_info
,
3114 err
= __check_buffer_access(env
, buf_info
, reg
, regno
, off
, size
);
3118 if (off
+ size
> *max_access
)
3119 *max_access
= off
+ size
;
3124 /* BPF architecture zero extends alu32 ops into 64-bit registesr */
3125 static void zext_32_to_64(struct bpf_reg_state
*reg
)
3127 reg
->var_off
= tnum_subreg(reg
->var_off
);
3128 __reg_assign_32_into_64(reg
);
3131 /* truncate register to smaller size (in bytes)
3132 * must be called with size < BPF_REG_SIZE
3134 static void coerce_reg_to_size(struct bpf_reg_state
*reg
, int size
)
3138 /* clear high bits in bit representation */
3139 reg
->var_off
= tnum_cast(reg
->var_off
, size
);
3141 /* fix arithmetic bounds */
3142 mask
= ((u64
)1 << (size
* 8)) - 1;
3143 if ((reg
->umin_value
& ~mask
) == (reg
->umax_value
& ~mask
)) {
3144 reg
->umin_value
&= mask
;
3145 reg
->umax_value
&= mask
;
3147 reg
->umin_value
= 0;
3148 reg
->umax_value
= mask
;
3150 reg
->smin_value
= reg
->umin_value
;
3151 reg
->smax_value
= reg
->umax_value
;
3153 /* If size is smaller than 32bit register the 32bit register
3154 * values are also truncated so we push 64-bit bounds into
3155 * 32-bit bounds. Above were truncated < 32-bits already.
3159 __reg_combine_64_into_32(reg
);
3162 static bool bpf_map_is_rdonly(const struct bpf_map
*map
)
3164 return (map
->map_flags
& BPF_F_RDONLY_PROG
) && map
->frozen
;
3167 static int bpf_map_direct_read(struct bpf_map
*map
, int off
, int size
, u64
*val
)
3173 err
= map
->ops
->map_direct_value_addr(map
, &addr
, off
);
3176 ptr
= (void *)(long)addr
+ off
;
3180 *val
= (u64
)*(u8
*)ptr
;
3183 *val
= (u64
)*(u16
*)ptr
;
3186 *val
= (u64
)*(u32
*)ptr
;
3197 static int check_ptr_to_btf_access(struct bpf_verifier_env
*env
,
3198 struct bpf_reg_state
*regs
,
3199 int regno
, int off
, int size
,
3200 enum bpf_access_type atype
,
3203 struct bpf_reg_state
*reg
= regs
+ regno
;
3204 const struct btf_type
*t
= btf_type_by_id(btf_vmlinux
, reg
->btf_id
);
3205 const char *tname
= btf_name_by_offset(btf_vmlinux
, t
->name_off
);
3211 "R%d is ptr_%s invalid negative access: off=%d\n",
3215 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
3218 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3220 "R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n",
3221 regno
, tname
, off
, tn_buf
);
3225 if (env
->ops
->btf_struct_access
) {
3226 ret
= env
->ops
->btf_struct_access(&env
->log
, t
, off
, size
,
3229 if (atype
!= BPF_READ
) {
3230 verbose(env
, "only read is supported\n");
3234 ret
= btf_struct_access(&env
->log
, t
, off
, size
, atype
,
3241 if (atype
== BPF_READ
&& value_regno
>= 0)
3242 mark_btf_ld_reg(env
, regs
, value_regno
, ret
, btf_id
);
3247 static int check_ptr_to_map_access(struct bpf_verifier_env
*env
,
3248 struct bpf_reg_state
*regs
,
3249 int regno
, int off
, int size
,
3250 enum bpf_access_type atype
,
3253 struct bpf_reg_state
*reg
= regs
+ regno
;
3254 struct bpf_map
*map
= reg
->map_ptr
;
3255 const struct btf_type
*t
;
3261 verbose(env
, "map_ptr access not supported without CONFIG_DEBUG_INFO_BTF\n");
3265 if (!map
->ops
->map_btf_id
|| !*map
->ops
->map_btf_id
) {
3266 verbose(env
, "map_ptr access not supported for map type %d\n",
3271 t
= btf_type_by_id(btf_vmlinux
, *map
->ops
->map_btf_id
);
3272 tname
= btf_name_by_offset(btf_vmlinux
, t
->name_off
);
3274 if (!env
->allow_ptr_to_map_access
) {
3276 "%s access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
3282 verbose(env
, "R%d is %s invalid negative access: off=%d\n",
3287 if (atype
!= BPF_READ
) {
3288 verbose(env
, "only read from %s is supported\n", tname
);
3292 ret
= btf_struct_access(&env
->log
, t
, off
, size
, atype
, &btf_id
);
3296 if (value_regno
>= 0)
3297 mark_btf_ld_reg(env
, regs
, value_regno
, ret
, btf_id
);
3303 /* check whether memory at (regno + off) is accessible for t = (read | write)
3304 * if t==write, value_regno is a register which value is stored into memory
3305 * if t==read, value_regno is a register which will receive the value from memory
3306 * if t==write && value_regno==-1, some unknown value is stored into memory
3307 * if t==read && value_regno==-1, don't care what we read from memory
3309 static int check_mem_access(struct bpf_verifier_env
*env
, int insn_idx
, u32 regno
,
3310 int off
, int bpf_size
, enum bpf_access_type t
,
3311 int value_regno
, bool strict_alignment_once
)
3313 struct bpf_reg_state
*regs
= cur_regs(env
);
3314 struct bpf_reg_state
*reg
= regs
+ regno
;
3315 struct bpf_func_state
*state
;
3318 size
= bpf_size_to_bytes(bpf_size
);
3322 /* alignment checks will add in reg->off themselves */
3323 err
= check_ptr_alignment(env
, reg
, off
, size
, strict_alignment_once
);
3327 /* for access checks, reg->off is just part of off */
3330 if (reg
->type
== PTR_TO_MAP_VALUE
) {
3331 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
3332 is_pointer_value(env
, value_regno
)) {
3333 verbose(env
, "R%d leaks addr into map\n", value_regno
);
3336 err
= check_map_access_type(env
, regno
, off
, size
, t
);
3339 err
= check_map_access(env
, regno
, off
, size
, false);
3340 if (!err
&& t
== BPF_READ
&& value_regno
>= 0) {
3341 struct bpf_map
*map
= reg
->map_ptr
;
3343 /* if map is read-only, track its contents as scalars */
3344 if (tnum_is_const(reg
->var_off
) &&
3345 bpf_map_is_rdonly(map
) &&
3346 map
->ops
->map_direct_value_addr
) {
3347 int map_off
= off
+ reg
->var_off
.value
;
3350 err
= bpf_map_direct_read(map
, map_off
, size
,
3355 regs
[value_regno
].type
= SCALAR_VALUE
;
3356 __mark_reg_known(®s
[value_regno
], val
);
3358 mark_reg_unknown(env
, regs
, value_regno
);
3361 } else if (reg
->type
== PTR_TO_MEM
) {
3362 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
3363 is_pointer_value(env
, value_regno
)) {
3364 verbose(env
, "R%d leaks addr into mem\n", value_regno
);
3367 err
= check_mem_region_access(env
, regno
, off
, size
,
3368 reg
->mem_size
, false);
3369 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
3370 mark_reg_unknown(env
, regs
, value_regno
);
3371 } else if (reg
->type
== PTR_TO_CTX
) {
3372 enum bpf_reg_type reg_type
= SCALAR_VALUE
;
3375 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
3376 is_pointer_value(env
, value_regno
)) {
3377 verbose(env
, "R%d leaks addr into ctx\n", value_regno
);
3381 err
= check_ctx_reg(env
, reg
, regno
);
3385 err
= check_ctx_access(env
, insn_idx
, off
, size
, t
, ®_type
, &btf_id
);
3387 verbose_linfo(env
, insn_idx
, "; ");
3388 if (!err
&& t
== BPF_READ
&& value_regno
>= 0) {
3389 /* ctx access returns either a scalar, or a
3390 * PTR_TO_PACKET[_META,_END]. In the latter
3391 * case, we know the offset is zero.
3393 if (reg_type
== SCALAR_VALUE
) {
3394 mark_reg_unknown(env
, regs
, value_regno
);
3396 mark_reg_known_zero(env
, regs
,
3398 if (reg_type_may_be_null(reg_type
))
3399 regs
[value_regno
].id
= ++env
->id_gen
;
3400 /* A load of ctx field could have different
3401 * actual load size with the one encoded in the
3402 * insn. When the dst is PTR, it is for sure not
3405 regs
[value_regno
].subreg_def
= DEF_NOT_SUBREG
;
3406 if (reg_type
== PTR_TO_BTF_ID
||
3407 reg_type
== PTR_TO_BTF_ID_OR_NULL
)
3408 regs
[value_regno
].btf_id
= btf_id
;
3410 regs
[value_regno
].type
= reg_type
;
3413 } else if (reg
->type
== PTR_TO_STACK
) {
3414 off
+= reg
->var_off
.value
;
3415 err
= check_stack_access(env
, reg
, off
, size
);
3419 state
= func(env
, reg
);
3420 err
= update_stack_depth(env
, state
, off
);
3425 err
= check_stack_write(env
, state
, off
, size
,
3426 value_regno
, insn_idx
);
3428 err
= check_stack_read(env
, state
, off
, size
,
3430 } else if (reg_is_pkt_pointer(reg
)) {
3431 if (t
== BPF_WRITE
&& !may_access_direct_pkt_data(env
, NULL
, t
)) {
3432 verbose(env
, "cannot write into packet\n");
3435 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
3436 is_pointer_value(env
, value_regno
)) {
3437 verbose(env
, "R%d leaks addr into packet\n",
3441 err
= check_packet_access(env
, regno
, off
, size
, false);
3442 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
3443 mark_reg_unknown(env
, regs
, value_regno
);
3444 } else if (reg
->type
== PTR_TO_FLOW_KEYS
) {
3445 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
3446 is_pointer_value(env
, value_regno
)) {
3447 verbose(env
, "R%d leaks addr into flow keys\n",
3452 err
= check_flow_keys_access(env
, off
, size
);
3453 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
3454 mark_reg_unknown(env
, regs
, value_regno
);
3455 } else if (type_is_sk_pointer(reg
->type
)) {
3456 if (t
== BPF_WRITE
) {
3457 verbose(env
, "R%d cannot write into %s\n",
3458 regno
, reg_type_str
[reg
->type
]);
3461 err
= check_sock_access(env
, insn_idx
, regno
, off
, size
, t
);
3462 if (!err
&& value_regno
>= 0)
3463 mark_reg_unknown(env
, regs
, value_regno
);
3464 } else if (reg
->type
== PTR_TO_TP_BUFFER
) {
3465 err
= check_tp_buffer_access(env
, reg
, regno
, off
, size
);
3466 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
3467 mark_reg_unknown(env
, regs
, value_regno
);
3468 } else if (reg
->type
== PTR_TO_BTF_ID
) {
3469 err
= check_ptr_to_btf_access(env
, regs
, regno
, off
, size
, t
,
3471 } else if (reg
->type
== CONST_PTR_TO_MAP
) {
3472 err
= check_ptr_to_map_access(env
, regs
, regno
, off
, size
, t
,
3474 } else if (reg
->type
== PTR_TO_RDONLY_BUF
) {
3475 if (t
== BPF_WRITE
) {
3476 verbose(env
, "R%d cannot write into %s\n",
3477 regno
, reg_type_str
[reg
->type
]);
3480 err
= check_buffer_access(env
, reg
, regno
, off
, size
, false,
3482 &env
->prog
->aux
->max_rdonly_access
);
3483 if (!err
&& value_regno
>= 0)
3484 mark_reg_unknown(env
, regs
, value_regno
);
3485 } else if (reg
->type
== PTR_TO_RDWR_BUF
) {
3486 err
= check_buffer_access(env
, reg
, regno
, off
, size
, false,
3488 &env
->prog
->aux
->max_rdwr_access
);
3489 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
3490 mark_reg_unknown(env
, regs
, value_regno
);
3492 verbose(env
, "R%d invalid mem access '%s'\n", regno
,
3493 reg_type_str
[reg
->type
]);
3497 if (!err
&& size
< BPF_REG_SIZE
&& value_regno
>= 0 && t
== BPF_READ
&&
3498 regs
[value_regno
].type
== SCALAR_VALUE
) {
3499 /* b/h/w load zero-extends, mark upper bits as known 0 */
3500 coerce_reg_to_size(®s
[value_regno
], size
);
3505 static int check_xadd(struct bpf_verifier_env
*env
, int insn_idx
, struct bpf_insn
*insn
)
3509 if ((BPF_SIZE(insn
->code
) != BPF_W
&& BPF_SIZE(insn
->code
) != BPF_DW
) ||
3511 verbose(env
, "BPF_XADD uses reserved fields\n");
3515 /* check src1 operand */
3516 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
3520 /* check src2 operand */
3521 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
3525 if (is_pointer_value(env
, insn
->src_reg
)) {
3526 verbose(env
, "R%d leaks addr into mem\n", insn
->src_reg
);
3530 if (is_ctx_reg(env
, insn
->dst_reg
) ||
3531 is_pkt_reg(env
, insn
->dst_reg
) ||
3532 is_flow_key_reg(env
, insn
->dst_reg
) ||
3533 is_sk_reg(env
, insn
->dst_reg
)) {
3534 verbose(env
, "BPF_XADD stores into R%d %s is not allowed\n",
3536 reg_type_str
[reg_state(env
, insn
->dst_reg
)->type
]);
3540 /* check whether atomic_add can read the memory */
3541 err
= check_mem_access(env
, insn_idx
, insn
->dst_reg
, insn
->off
,
3542 BPF_SIZE(insn
->code
), BPF_READ
, -1, true);
3546 /* check whether atomic_add can write into the same memory */
3547 return check_mem_access(env
, insn_idx
, insn
->dst_reg
, insn
->off
,
3548 BPF_SIZE(insn
->code
), BPF_WRITE
, -1, true);
3551 static int __check_stack_boundary(struct bpf_verifier_env
*env
, u32 regno
,
3552 int off
, int access_size
,
3553 bool zero_size_allowed
)
3555 struct bpf_reg_state
*reg
= reg_state(env
, regno
);
3557 if (off
>= 0 || off
< -MAX_BPF_STACK
|| off
+ access_size
> 0 ||
3558 access_size
< 0 || (access_size
== 0 && !zero_size_allowed
)) {
3559 if (tnum_is_const(reg
->var_off
)) {
3560 verbose(env
, "invalid stack type R%d off=%d access_size=%d\n",
3561 regno
, off
, access_size
);
3565 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3566 verbose(env
, "invalid stack type R%d var_off=%s access_size=%d\n",
3567 regno
, tn_buf
, access_size
);
3574 /* when register 'regno' is passed into function that will read 'access_size'
3575 * bytes from that pointer, make sure that it's within stack boundary
3576 * and all elements of stack are initialized.
3577 * Unlike most pointer bounds-checking functions, this one doesn't take an
3578 * 'off' argument, so it has to add in reg->off itself.
3580 static int check_stack_boundary(struct bpf_verifier_env
*env
, int regno
,
3581 int access_size
, bool zero_size_allowed
,
3582 struct bpf_call_arg_meta
*meta
)
3584 struct bpf_reg_state
*reg
= reg_state(env
, regno
);
3585 struct bpf_func_state
*state
= func(env
, reg
);
3586 int err
, min_off
, max_off
, i
, j
, slot
, spi
;
3588 if (reg
->type
!= PTR_TO_STACK
) {
3589 /* Allow zero-byte read from NULL, regardless of pointer type */
3590 if (zero_size_allowed
&& access_size
== 0 &&
3591 register_is_null(reg
))
3594 verbose(env
, "R%d type=%s expected=%s\n", regno
,
3595 reg_type_str
[reg
->type
],
3596 reg_type_str
[PTR_TO_STACK
]);
3600 if (tnum_is_const(reg
->var_off
)) {
3601 min_off
= max_off
= reg
->var_off
.value
+ reg
->off
;
3602 err
= __check_stack_boundary(env
, regno
, min_off
, access_size
,
3607 /* Variable offset is prohibited for unprivileged mode for
3608 * simplicity since it requires corresponding support in
3609 * Spectre masking for stack ALU.
3610 * See also retrieve_ptr_limit().
3612 if (!env
->bypass_spec_v1
) {
3615 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3616 verbose(env
, "R%d indirect variable offset stack access prohibited for !root, var_off=%s\n",
3620 /* Only initialized buffer on stack is allowed to be accessed
3621 * with variable offset. With uninitialized buffer it's hard to
3622 * guarantee that whole memory is marked as initialized on
3623 * helper return since specific bounds are unknown what may
3624 * cause uninitialized stack leaking.
3626 if (meta
&& meta
->raw_mode
)
3629 if (reg
->smax_value
>= BPF_MAX_VAR_OFF
||
3630 reg
->smax_value
<= -BPF_MAX_VAR_OFF
) {
3631 verbose(env
, "R%d unbounded indirect variable offset stack access\n",
3635 min_off
= reg
->smin_value
+ reg
->off
;
3636 max_off
= reg
->smax_value
+ reg
->off
;
3637 err
= __check_stack_boundary(env
, regno
, min_off
, access_size
,
3640 verbose(env
, "R%d min value is outside of stack bound\n",
3644 err
= __check_stack_boundary(env
, regno
, max_off
, access_size
,
3647 verbose(env
, "R%d max value is outside of stack bound\n",
3653 if (meta
&& meta
->raw_mode
) {
3654 meta
->access_size
= access_size
;
3655 meta
->regno
= regno
;
3659 for (i
= min_off
; i
< max_off
+ access_size
; i
++) {
3663 spi
= slot
/ BPF_REG_SIZE
;
3664 if (state
->allocated_stack
<= slot
)
3666 stype
= &state
->stack
[spi
].slot_type
[slot
% BPF_REG_SIZE
];
3667 if (*stype
== STACK_MISC
)
3669 if (*stype
== STACK_ZERO
) {
3670 /* helper can write anything into the stack */
3671 *stype
= STACK_MISC
;
3675 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
3676 state
->stack
[spi
].spilled_ptr
.type
== PTR_TO_BTF_ID
)
3679 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
3680 state
->stack
[spi
].spilled_ptr
.type
== SCALAR_VALUE
) {
3681 __mark_reg_unknown(env
, &state
->stack
[spi
].spilled_ptr
);
3682 for (j
= 0; j
< BPF_REG_SIZE
; j
++)
3683 state
->stack
[spi
].slot_type
[j
] = STACK_MISC
;
3688 if (tnum_is_const(reg
->var_off
)) {
3689 verbose(env
, "invalid indirect read from stack off %d+%d size %d\n",
3690 min_off
, i
- min_off
, access_size
);
3694 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
3695 verbose(env
, "invalid indirect read from stack var_off %s+%d size %d\n",
3696 tn_buf
, i
- min_off
, access_size
);
3700 /* reading any byte out of 8-byte 'spill_slot' will cause
3701 * the whole slot to be marked as 'read'
3703 mark_reg_read(env
, &state
->stack
[spi
].spilled_ptr
,
3704 state
->stack
[spi
].spilled_ptr
.parent
,
3707 return update_stack_depth(env
, state
, min_off
);
3710 static int check_helper_mem_access(struct bpf_verifier_env
*env
, int regno
,
3711 int access_size
, bool zero_size_allowed
,
3712 struct bpf_call_arg_meta
*meta
)
3714 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
3716 switch (reg
->type
) {
3718 case PTR_TO_PACKET_META
:
3719 return check_packet_access(env
, regno
, reg
->off
, access_size
,
3721 case PTR_TO_MAP_VALUE
:
3722 if (check_map_access_type(env
, regno
, reg
->off
, access_size
,
3723 meta
&& meta
->raw_mode
? BPF_WRITE
:
3726 return check_map_access(env
, regno
, reg
->off
, access_size
,
3729 return check_mem_region_access(env
, regno
, reg
->off
,
3730 access_size
, reg
->mem_size
,
3732 case PTR_TO_RDONLY_BUF
:
3733 if (meta
&& meta
->raw_mode
)
3735 return check_buffer_access(env
, reg
, regno
, reg
->off
,
3736 access_size
, zero_size_allowed
,
3738 &env
->prog
->aux
->max_rdonly_access
);
3739 case PTR_TO_RDWR_BUF
:
3740 return check_buffer_access(env
, reg
, regno
, reg
->off
,
3741 access_size
, zero_size_allowed
,
3743 &env
->prog
->aux
->max_rdwr_access
);
3744 default: /* scalar_value|ptr_to_stack or invalid ptr */
3745 return check_stack_boundary(env
, regno
, access_size
,
3746 zero_size_allowed
, meta
);
3750 /* Implementation details:
3751 * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL
3752 * Two bpf_map_lookups (even with the same key) will have different reg->id.
3753 * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after
3754 * value_or_null->value transition, since the verifier only cares about
3755 * the range of access to valid map value pointer and doesn't care about actual
3756 * address of the map element.
3757 * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
3758 * reg->id > 0 after value_or_null->value transition. By doing so
3759 * two bpf_map_lookups will be considered two different pointers that
3760 * point to different bpf_spin_locks.
3761 * The verifier allows taking only one bpf_spin_lock at a time to avoid
3763 * Since only one bpf_spin_lock is allowed the checks are simpler than
3764 * reg_is_refcounted() logic. The verifier needs to remember only
3765 * one spin_lock instead of array of acquired_refs.
3766 * cur_state->active_spin_lock remembers which map value element got locked
3767 * and clears it after bpf_spin_unlock.
3769 static int process_spin_lock(struct bpf_verifier_env
*env
, int regno
,
3772 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
3773 struct bpf_verifier_state
*cur
= env
->cur_state
;
3774 bool is_const
= tnum_is_const(reg
->var_off
);
3775 struct bpf_map
*map
= reg
->map_ptr
;
3776 u64 val
= reg
->var_off
.value
;
3778 if (reg
->type
!= PTR_TO_MAP_VALUE
) {
3779 verbose(env
, "R%d is not a pointer to map_value\n", regno
);
3784 "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
3790 "map '%s' has to have BTF in order to use bpf_spin_lock\n",
3794 if (!map_value_has_spin_lock(map
)) {
3795 if (map
->spin_lock_off
== -E2BIG
)
3797 "map '%s' has more than one 'struct bpf_spin_lock'\n",
3799 else if (map
->spin_lock_off
== -ENOENT
)
3801 "map '%s' doesn't have 'struct bpf_spin_lock'\n",
3805 "map '%s' is not a struct type or bpf_spin_lock is mangled\n",
3809 if (map
->spin_lock_off
!= val
+ reg
->off
) {
3810 verbose(env
, "off %lld doesn't point to 'struct bpf_spin_lock'\n",
3815 if (cur
->active_spin_lock
) {
3817 "Locking two bpf_spin_locks are not allowed\n");
3820 cur
->active_spin_lock
= reg
->id
;
3822 if (!cur
->active_spin_lock
) {
3823 verbose(env
, "bpf_spin_unlock without taking a lock\n");
3826 if (cur
->active_spin_lock
!= reg
->id
) {
3827 verbose(env
, "bpf_spin_unlock of different lock\n");
3830 cur
->active_spin_lock
= 0;
3835 static bool arg_type_is_mem_ptr(enum bpf_arg_type type
)
3837 return type
== ARG_PTR_TO_MEM
||
3838 type
== ARG_PTR_TO_MEM_OR_NULL
||
3839 type
== ARG_PTR_TO_UNINIT_MEM
;
3842 static bool arg_type_is_mem_size(enum bpf_arg_type type
)
3844 return type
== ARG_CONST_SIZE
||
3845 type
== ARG_CONST_SIZE_OR_ZERO
;
3848 static bool arg_type_is_alloc_mem_ptr(enum bpf_arg_type type
)
3850 return type
== ARG_PTR_TO_ALLOC_MEM
||
3851 type
== ARG_PTR_TO_ALLOC_MEM_OR_NULL
;
3854 static bool arg_type_is_alloc_size(enum bpf_arg_type type
)
3856 return type
== ARG_CONST_ALLOC_SIZE_OR_ZERO
;
3859 static bool arg_type_is_int_ptr(enum bpf_arg_type type
)
3861 return type
== ARG_PTR_TO_INT
||
3862 type
== ARG_PTR_TO_LONG
;
3865 static int int_ptr_type_to_size(enum bpf_arg_type type
)
3867 if (type
== ARG_PTR_TO_INT
)
3869 else if (type
== ARG_PTR_TO_LONG
)
3875 static int check_func_arg(struct bpf_verifier_env
*env
, u32 arg
,
3876 struct bpf_call_arg_meta
*meta
,
3877 const struct bpf_func_proto
*fn
)
3879 u32 regno
= BPF_REG_1
+ arg
;
3880 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
3881 enum bpf_reg_type expected_type
, type
= reg
->type
;
3882 enum bpf_arg_type arg_type
= fn
->arg_type
[arg
];
3885 if (arg_type
== ARG_DONTCARE
)
3888 err
= check_reg_arg(env
, regno
, SRC_OP
);
3892 if (arg_type
== ARG_ANYTHING
) {
3893 if (is_pointer_value(env
, regno
)) {
3894 verbose(env
, "R%d leaks addr into helper function\n",
3901 if (type_is_pkt_pointer(type
) &&
3902 !may_access_direct_pkt_data(env
, meta
, BPF_READ
)) {
3903 verbose(env
, "helper access to the packet is not allowed\n");
3907 if (arg_type
== ARG_PTR_TO_MAP_KEY
||
3908 arg_type
== ARG_PTR_TO_MAP_VALUE
||
3909 arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
||
3910 arg_type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
) {
3911 expected_type
= PTR_TO_STACK
;
3912 if (register_is_null(reg
) &&
3913 arg_type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
)
3914 /* final test in check_stack_boundary() */;
3915 else if (!type_is_pkt_pointer(type
) &&
3916 type
!= PTR_TO_MAP_VALUE
&&
3917 type
!= expected_type
)
3919 } else if (arg_type
== ARG_CONST_SIZE
||
3920 arg_type
== ARG_CONST_SIZE_OR_ZERO
||
3921 arg_type
== ARG_CONST_ALLOC_SIZE_OR_ZERO
) {
3922 expected_type
= SCALAR_VALUE
;
3923 if (type
!= expected_type
)
3925 } else if (arg_type
== ARG_CONST_MAP_PTR
) {
3926 expected_type
= CONST_PTR_TO_MAP
;
3927 if (type
!= expected_type
)
3929 } else if (arg_type
== ARG_PTR_TO_CTX
||
3930 arg_type
== ARG_PTR_TO_CTX_OR_NULL
) {
3931 expected_type
= PTR_TO_CTX
;
3932 if (!(register_is_null(reg
) &&
3933 arg_type
== ARG_PTR_TO_CTX_OR_NULL
)) {
3934 if (type
!= expected_type
)
3936 err
= check_ctx_reg(env
, reg
, regno
);
3940 } else if (arg_type
== ARG_PTR_TO_SOCK_COMMON
) {
3941 expected_type
= PTR_TO_SOCK_COMMON
;
3942 /* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */
3943 if (!type_is_sk_pointer(type
))
3945 if (reg
->ref_obj_id
) {
3946 if (meta
->ref_obj_id
) {
3947 verbose(env
, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
3948 regno
, reg
->ref_obj_id
,
3952 meta
->ref_obj_id
= reg
->ref_obj_id
;
3954 } else if (arg_type
== ARG_PTR_TO_SOCKET
||
3955 arg_type
== ARG_PTR_TO_SOCKET_OR_NULL
) {
3956 expected_type
= PTR_TO_SOCKET
;
3957 if (!(register_is_null(reg
) &&
3958 arg_type
== ARG_PTR_TO_SOCKET_OR_NULL
)) {
3959 if (type
!= expected_type
)
3962 } else if (arg_type
== ARG_PTR_TO_BTF_ID
) {
3963 expected_type
= PTR_TO_BTF_ID
;
3964 if (type
!= expected_type
)
3966 if (!fn
->check_btf_id
) {
3967 if (reg
->btf_id
!= meta
->btf_id
) {
3968 verbose(env
, "Helper has type %s got %s in R%d\n",
3969 kernel_type_name(meta
->btf_id
),
3970 kernel_type_name(reg
->btf_id
), regno
);
3974 } else if (!fn
->check_btf_id(reg
->btf_id
, arg
)) {
3975 verbose(env
, "Helper does not support %s in R%d\n",
3976 kernel_type_name(reg
->btf_id
), regno
);
3980 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
|| reg
->off
) {
3981 verbose(env
, "R%d is a pointer to in-kernel struct with non-zero offset\n",
3985 } else if (arg_type
== ARG_PTR_TO_SPIN_LOCK
) {
3986 if (meta
->func_id
== BPF_FUNC_spin_lock
) {
3987 if (process_spin_lock(env
, regno
, true))
3989 } else if (meta
->func_id
== BPF_FUNC_spin_unlock
) {
3990 if (process_spin_lock(env
, regno
, false))
3993 verbose(env
, "verifier internal error\n");
3996 } else if (arg_type_is_mem_ptr(arg_type
)) {
3997 expected_type
= PTR_TO_STACK
;
3998 /* One exception here. In case function allows for NULL to be
3999 * passed in as argument, it's a SCALAR_VALUE type. Final test
4000 * happens during stack boundary checking.
4002 if (register_is_null(reg
) &&
4003 (arg_type
== ARG_PTR_TO_MEM_OR_NULL
||
4004 arg_type
== ARG_PTR_TO_ALLOC_MEM_OR_NULL
))
4005 /* final test in check_stack_boundary() */;
4006 else if (!type_is_pkt_pointer(type
) &&
4007 type
!= PTR_TO_MAP_VALUE
&&
4008 type
!= PTR_TO_MEM
&&
4009 type
!= PTR_TO_RDONLY_BUF
&&
4010 type
!= PTR_TO_RDWR_BUF
&&
4011 type
!= expected_type
)
4013 meta
->raw_mode
= arg_type
== ARG_PTR_TO_UNINIT_MEM
;
4014 } else if (arg_type_is_alloc_mem_ptr(arg_type
)) {
4015 expected_type
= PTR_TO_MEM
;
4016 if (register_is_null(reg
) &&
4017 arg_type
== ARG_PTR_TO_ALLOC_MEM_OR_NULL
)
4018 /* final test in check_stack_boundary() */;
4019 else if (type
!= expected_type
)
4021 if (meta
->ref_obj_id
) {
4022 verbose(env
, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
4023 regno
, reg
->ref_obj_id
,
4027 meta
->ref_obj_id
= reg
->ref_obj_id
;
4028 } else if (arg_type_is_int_ptr(arg_type
)) {
4029 expected_type
= PTR_TO_STACK
;
4030 if (!type_is_pkt_pointer(type
) &&
4031 type
!= PTR_TO_MAP_VALUE
&&
4032 type
!= expected_type
)
4035 verbose(env
, "unsupported arg_type %d\n", arg_type
);
4039 if (arg_type
== ARG_CONST_MAP_PTR
) {
4040 /* bpf_map_xxx(map_ptr) call: remember that map_ptr */
4041 meta
->map_ptr
= reg
->map_ptr
;
4042 } else if (arg_type
== ARG_PTR_TO_MAP_KEY
) {
4043 /* bpf_map_xxx(..., map_ptr, ..., key) call:
4044 * check that [key, key + map->key_size) are within
4045 * stack limits and initialized
4047 if (!meta
->map_ptr
) {
4048 /* in function declaration map_ptr must come before
4049 * map_key, so that it's verified and known before
4050 * we have to check map_key here. Otherwise it means
4051 * that kernel subsystem misconfigured verifier
4053 verbose(env
, "invalid map_ptr to access map->key\n");
4056 err
= check_helper_mem_access(env
, regno
,
4057 meta
->map_ptr
->key_size
, false,
4059 } else if (arg_type
== ARG_PTR_TO_MAP_VALUE
||
4060 (arg_type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
&&
4061 !register_is_null(reg
)) ||
4062 arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
) {
4063 /* bpf_map_xxx(..., map_ptr, ..., value) call:
4064 * check [value, value + map->value_size) validity
4066 if (!meta
->map_ptr
) {
4067 /* kernel subsystem misconfigured verifier */
4068 verbose(env
, "invalid map_ptr to access map->value\n");
4071 meta
->raw_mode
= (arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
);
4072 err
= check_helper_mem_access(env
, regno
,
4073 meta
->map_ptr
->value_size
, false,
4075 } else if (arg_type_is_mem_size(arg_type
)) {
4076 bool zero_size_allowed
= (arg_type
== ARG_CONST_SIZE_OR_ZERO
);
4078 /* This is used to refine r0 return value bounds for helpers
4079 * that enforce this value as an upper bound on return values.
4080 * See do_refine_retval_range() for helpers that can refine
4081 * the return value. C type of helper is u32 so we pull register
4082 * bound from umax_value however, if negative verifier errors
4083 * out. Only upper bounds can be learned because retval is an
4084 * int type and negative retvals are allowed.
4086 meta
->msize_max_value
= reg
->umax_value
;
4088 /* The register is SCALAR_VALUE; the access check
4089 * happens using its boundaries.
4091 if (!tnum_is_const(reg
->var_off
))
4092 /* For unprivileged variable accesses, disable raw
4093 * mode so that the program is required to
4094 * initialize all the memory that the helper could
4095 * just partially fill up.
4099 if (reg
->smin_value
< 0) {
4100 verbose(env
, "R%d min value is negative, either use unsigned or 'var &= const'\n",
4105 if (reg
->umin_value
== 0) {
4106 err
= check_helper_mem_access(env
, regno
- 1, 0,
4113 if (reg
->umax_value
>= BPF_MAX_VAR_SIZ
) {
4114 verbose(env
, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
4118 err
= check_helper_mem_access(env
, regno
- 1,
4120 zero_size_allowed
, meta
);
4122 err
= mark_chain_precision(env
, regno
);
4123 } else if (arg_type_is_alloc_size(arg_type
)) {
4124 if (!tnum_is_const(reg
->var_off
)) {
4125 verbose(env
, "R%d unbounded size, use 'var &= const' or 'if (var < const)'\n",
4129 meta
->mem_size
= reg
->var_off
.value
;
4130 } else if (arg_type_is_int_ptr(arg_type
)) {
4131 int size
= int_ptr_type_to_size(arg_type
);
4133 err
= check_helper_mem_access(env
, regno
, size
, false, meta
);
4136 err
= check_ptr_alignment(env
, reg
, 0, size
, true);
4141 verbose(env
, "R%d type=%s expected=%s\n", regno
,
4142 reg_type_str
[type
], reg_type_str
[expected_type
]);
4146 static int check_map_func_compatibility(struct bpf_verifier_env
*env
,
4147 struct bpf_map
*map
, int func_id
)
4152 /* We need a two way check, first is from map perspective ... */
4153 switch (map
->map_type
) {
4154 case BPF_MAP_TYPE_PROG_ARRAY
:
4155 if (func_id
!= BPF_FUNC_tail_call
)
4158 case BPF_MAP_TYPE_PERF_EVENT_ARRAY
:
4159 if (func_id
!= BPF_FUNC_perf_event_read
&&
4160 func_id
!= BPF_FUNC_perf_event_output
&&
4161 func_id
!= BPF_FUNC_skb_output
&&
4162 func_id
!= BPF_FUNC_perf_event_read_value
&&
4163 func_id
!= BPF_FUNC_xdp_output
)
4166 case BPF_MAP_TYPE_RINGBUF
:
4167 if (func_id
!= BPF_FUNC_ringbuf_output
&&
4168 func_id
!= BPF_FUNC_ringbuf_reserve
&&
4169 func_id
!= BPF_FUNC_ringbuf_submit
&&
4170 func_id
!= BPF_FUNC_ringbuf_discard
&&
4171 func_id
!= BPF_FUNC_ringbuf_query
)
4174 case BPF_MAP_TYPE_STACK_TRACE
:
4175 if (func_id
!= BPF_FUNC_get_stackid
)
4178 case BPF_MAP_TYPE_CGROUP_ARRAY
:
4179 if (func_id
!= BPF_FUNC_skb_under_cgroup
&&
4180 func_id
!= BPF_FUNC_current_task_under_cgroup
)
4183 case BPF_MAP_TYPE_CGROUP_STORAGE
:
4184 case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
:
4185 if (func_id
!= BPF_FUNC_get_local_storage
)
4188 case BPF_MAP_TYPE_DEVMAP
:
4189 case BPF_MAP_TYPE_DEVMAP_HASH
:
4190 if (func_id
!= BPF_FUNC_redirect_map
&&
4191 func_id
!= BPF_FUNC_map_lookup_elem
)
4194 /* Restrict bpf side of cpumap and xskmap, open when use-cases
4197 case BPF_MAP_TYPE_CPUMAP
:
4198 if (func_id
!= BPF_FUNC_redirect_map
)
4201 case BPF_MAP_TYPE_XSKMAP
:
4202 if (func_id
!= BPF_FUNC_redirect_map
&&
4203 func_id
!= BPF_FUNC_map_lookup_elem
)
4206 case BPF_MAP_TYPE_ARRAY_OF_MAPS
:
4207 case BPF_MAP_TYPE_HASH_OF_MAPS
:
4208 if (func_id
!= BPF_FUNC_map_lookup_elem
)
4211 case BPF_MAP_TYPE_SOCKMAP
:
4212 if (func_id
!= BPF_FUNC_sk_redirect_map
&&
4213 func_id
!= BPF_FUNC_sock_map_update
&&
4214 func_id
!= BPF_FUNC_map_delete_elem
&&
4215 func_id
!= BPF_FUNC_msg_redirect_map
&&
4216 func_id
!= BPF_FUNC_sk_select_reuseport
&&
4217 func_id
!= BPF_FUNC_map_lookup_elem
)
4220 case BPF_MAP_TYPE_SOCKHASH
:
4221 if (func_id
!= BPF_FUNC_sk_redirect_hash
&&
4222 func_id
!= BPF_FUNC_sock_hash_update
&&
4223 func_id
!= BPF_FUNC_map_delete_elem
&&
4224 func_id
!= BPF_FUNC_msg_redirect_hash
&&
4225 func_id
!= BPF_FUNC_sk_select_reuseport
&&
4226 func_id
!= BPF_FUNC_map_lookup_elem
)
4229 case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY
:
4230 if (func_id
!= BPF_FUNC_sk_select_reuseport
)
4233 case BPF_MAP_TYPE_QUEUE
:
4234 case BPF_MAP_TYPE_STACK
:
4235 if (func_id
!= BPF_FUNC_map_peek_elem
&&
4236 func_id
!= BPF_FUNC_map_pop_elem
&&
4237 func_id
!= BPF_FUNC_map_push_elem
)
4240 case BPF_MAP_TYPE_SK_STORAGE
:
4241 if (func_id
!= BPF_FUNC_sk_storage_get
&&
4242 func_id
!= BPF_FUNC_sk_storage_delete
)
4249 /* ... and second from the function itself. */
4251 case BPF_FUNC_tail_call
:
4252 if (map
->map_type
!= BPF_MAP_TYPE_PROG_ARRAY
)
4254 if (env
->subprog_cnt
> 1) {
4255 verbose(env
, "tail_calls are not allowed in programs with bpf-to-bpf calls\n");
4259 case BPF_FUNC_perf_event_read
:
4260 case BPF_FUNC_perf_event_output
:
4261 case BPF_FUNC_perf_event_read_value
:
4262 case BPF_FUNC_skb_output
:
4263 case BPF_FUNC_xdp_output
:
4264 if (map
->map_type
!= BPF_MAP_TYPE_PERF_EVENT_ARRAY
)
4267 case BPF_FUNC_get_stackid
:
4268 if (map
->map_type
!= BPF_MAP_TYPE_STACK_TRACE
)
4271 case BPF_FUNC_current_task_under_cgroup
:
4272 case BPF_FUNC_skb_under_cgroup
:
4273 if (map
->map_type
!= BPF_MAP_TYPE_CGROUP_ARRAY
)
4276 case BPF_FUNC_redirect_map
:
4277 if (map
->map_type
!= BPF_MAP_TYPE_DEVMAP
&&
4278 map
->map_type
!= BPF_MAP_TYPE_DEVMAP_HASH
&&
4279 map
->map_type
!= BPF_MAP_TYPE_CPUMAP
&&
4280 map
->map_type
!= BPF_MAP_TYPE_XSKMAP
)
4283 case BPF_FUNC_sk_redirect_map
:
4284 case BPF_FUNC_msg_redirect_map
:
4285 case BPF_FUNC_sock_map_update
:
4286 if (map
->map_type
!= BPF_MAP_TYPE_SOCKMAP
)
4289 case BPF_FUNC_sk_redirect_hash
:
4290 case BPF_FUNC_msg_redirect_hash
:
4291 case BPF_FUNC_sock_hash_update
:
4292 if (map
->map_type
!= BPF_MAP_TYPE_SOCKHASH
)
4295 case BPF_FUNC_get_local_storage
:
4296 if (map
->map_type
!= BPF_MAP_TYPE_CGROUP_STORAGE
&&
4297 map
->map_type
!= BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
)
4300 case BPF_FUNC_sk_select_reuseport
:
4301 if (map
->map_type
!= BPF_MAP_TYPE_REUSEPORT_SOCKARRAY
&&
4302 map
->map_type
!= BPF_MAP_TYPE_SOCKMAP
&&
4303 map
->map_type
!= BPF_MAP_TYPE_SOCKHASH
)
4306 case BPF_FUNC_map_peek_elem
:
4307 case BPF_FUNC_map_pop_elem
:
4308 case BPF_FUNC_map_push_elem
:
4309 if (map
->map_type
!= BPF_MAP_TYPE_QUEUE
&&
4310 map
->map_type
!= BPF_MAP_TYPE_STACK
)
4313 case BPF_FUNC_sk_storage_get
:
4314 case BPF_FUNC_sk_storage_delete
:
4315 if (map
->map_type
!= BPF_MAP_TYPE_SK_STORAGE
)
4324 verbose(env
, "cannot pass map_type %d into func %s#%d\n",
4325 map
->map_type
, func_id_name(func_id
), func_id
);
4329 static bool check_raw_mode_ok(const struct bpf_func_proto
*fn
)
4333 if (fn
->arg1_type
== ARG_PTR_TO_UNINIT_MEM
)
4335 if (fn
->arg2_type
== ARG_PTR_TO_UNINIT_MEM
)
4337 if (fn
->arg3_type
== ARG_PTR_TO_UNINIT_MEM
)
4339 if (fn
->arg4_type
== ARG_PTR_TO_UNINIT_MEM
)
4341 if (fn
->arg5_type
== ARG_PTR_TO_UNINIT_MEM
)
4344 /* We only support one arg being in raw mode at the moment,
4345 * which is sufficient for the helper functions we have
4351 static bool check_args_pair_invalid(enum bpf_arg_type arg_curr
,
4352 enum bpf_arg_type arg_next
)
4354 return (arg_type_is_mem_ptr(arg_curr
) &&
4355 !arg_type_is_mem_size(arg_next
)) ||
4356 (!arg_type_is_mem_ptr(arg_curr
) &&
4357 arg_type_is_mem_size(arg_next
));
4360 static bool check_arg_pair_ok(const struct bpf_func_proto
*fn
)
4362 /* bpf_xxx(..., buf, len) call will access 'len'
4363 * bytes from memory 'buf'. Both arg types need
4364 * to be paired, so make sure there's no buggy
4365 * helper function specification.
4367 if (arg_type_is_mem_size(fn
->arg1_type
) ||
4368 arg_type_is_mem_ptr(fn
->arg5_type
) ||
4369 check_args_pair_invalid(fn
->arg1_type
, fn
->arg2_type
) ||
4370 check_args_pair_invalid(fn
->arg2_type
, fn
->arg3_type
) ||
4371 check_args_pair_invalid(fn
->arg3_type
, fn
->arg4_type
) ||
4372 check_args_pair_invalid(fn
->arg4_type
, fn
->arg5_type
))
4378 static bool check_refcount_ok(const struct bpf_func_proto
*fn
, int func_id
)
4382 if (arg_type_may_be_refcounted(fn
->arg1_type
))
4384 if (arg_type_may_be_refcounted(fn
->arg2_type
))
4386 if (arg_type_may_be_refcounted(fn
->arg3_type
))
4388 if (arg_type_may_be_refcounted(fn
->arg4_type
))
4390 if (arg_type_may_be_refcounted(fn
->arg5_type
))
4393 /* A reference acquiring function cannot acquire
4394 * another refcounted ptr.
4396 if (may_be_acquire_function(func_id
) && count
)
4399 /* We only support one arg being unreferenced at the moment,
4400 * which is sufficient for the helper functions we have right now.
4405 static int check_func_proto(const struct bpf_func_proto
*fn
, int func_id
)
4407 return check_raw_mode_ok(fn
) &&
4408 check_arg_pair_ok(fn
) &&
4409 check_refcount_ok(fn
, func_id
) ? 0 : -EINVAL
;
4412 /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
4413 * are now invalid, so turn them into unknown SCALAR_VALUE.
4415 static void __clear_all_pkt_pointers(struct bpf_verifier_env
*env
,
4416 struct bpf_func_state
*state
)
4418 struct bpf_reg_state
*regs
= state
->regs
, *reg
;
4421 for (i
= 0; i
< MAX_BPF_REG
; i
++)
4422 if (reg_is_pkt_pointer_any(®s
[i
]))
4423 mark_reg_unknown(env
, regs
, i
);
4425 bpf_for_each_spilled_reg(i
, state
, reg
) {
4428 if (reg_is_pkt_pointer_any(reg
))
4429 __mark_reg_unknown(env
, reg
);
4433 static void clear_all_pkt_pointers(struct bpf_verifier_env
*env
)
4435 struct bpf_verifier_state
*vstate
= env
->cur_state
;
4438 for (i
= 0; i
<= vstate
->curframe
; i
++)
4439 __clear_all_pkt_pointers(env
, vstate
->frame
[i
]);
4442 static void release_reg_references(struct bpf_verifier_env
*env
,
4443 struct bpf_func_state
*state
,
4446 struct bpf_reg_state
*regs
= state
->regs
, *reg
;
4449 for (i
= 0; i
< MAX_BPF_REG
; i
++)
4450 if (regs
[i
].ref_obj_id
== ref_obj_id
)
4451 mark_reg_unknown(env
, regs
, i
);
4453 bpf_for_each_spilled_reg(i
, state
, reg
) {
4456 if (reg
->ref_obj_id
== ref_obj_id
)
4457 __mark_reg_unknown(env
, reg
);
4461 /* The pointer with the specified id has released its reference to kernel
4462 * resources. Identify all copies of the same pointer and clear the reference.
4464 static int release_reference(struct bpf_verifier_env
*env
,
4467 struct bpf_verifier_state
*vstate
= env
->cur_state
;
4471 err
= release_reference_state(cur_func(env
), ref_obj_id
);
4475 for (i
= 0; i
<= vstate
->curframe
; i
++)
4476 release_reg_references(env
, vstate
->frame
[i
], ref_obj_id
);
4481 static void clear_caller_saved_regs(struct bpf_verifier_env
*env
,
4482 struct bpf_reg_state
*regs
)
4486 /* after the call registers r0 - r5 were scratched */
4487 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
4488 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
4489 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
4493 static int check_func_call(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
,
4496 struct bpf_verifier_state
*state
= env
->cur_state
;
4497 struct bpf_func_info_aux
*func_info_aux
;
4498 struct bpf_func_state
*caller
, *callee
;
4499 int i
, err
, subprog
, target_insn
;
4500 bool is_global
= false;
4502 if (state
->curframe
+ 1 >= MAX_CALL_FRAMES
) {
4503 verbose(env
, "the call stack of %d frames is too deep\n",
4504 state
->curframe
+ 2);
4508 target_insn
= *insn_idx
+ insn
->imm
;
4509 subprog
= find_subprog(env
, target_insn
+ 1);
4511 verbose(env
, "verifier bug. No program starts at insn %d\n",
4516 caller
= state
->frame
[state
->curframe
];
4517 if (state
->frame
[state
->curframe
+ 1]) {
4518 verbose(env
, "verifier bug. Frame %d already allocated\n",
4519 state
->curframe
+ 1);
4523 func_info_aux
= env
->prog
->aux
->func_info_aux
;
4525 is_global
= func_info_aux
[subprog
].linkage
== BTF_FUNC_GLOBAL
;
4526 err
= btf_check_func_arg_match(env
, subprog
, caller
->regs
);
4531 verbose(env
, "Caller passes invalid args into func#%d\n",
4535 if (env
->log
.level
& BPF_LOG_LEVEL
)
4537 "Func#%d is global and valid. Skipping.\n",
4539 clear_caller_saved_regs(env
, caller
->regs
);
4541 /* All global functions return SCALAR_VALUE */
4542 mark_reg_unknown(env
, caller
->regs
, BPF_REG_0
);
4544 /* continue with next insn after call */
4549 callee
= kzalloc(sizeof(*callee
), GFP_KERNEL
);
4552 state
->frame
[state
->curframe
+ 1] = callee
;
4554 /* callee cannot access r0, r6 - r9 for reading and has to write
4555 * into its own stack before reading from it.
4556 * callee can read/write into caller's stack
4558 init_func_state(env
, callee
,
4559 /* remember the callsite, it will be used by bpf_exit */
4560 *insn_idx
/* callsite */,
4561 state
->curframe
+ 1 /* frameno within this callchain */,
4562 subprog
/* subprog number within this prog */);
4564 /* Transfer references to the callee */
4565 err
= transfer_reference_state(callee
, caller
);
4569 /* copy r1 - r5 args that callee can access. The copy includes parent
4570 * pointers, which connects us up to the liveness chain
4572 for (i
= BPF_REG_1
; i
<= BPF_REG_5
; i
++)
4573 callee
->regs
[i
] = caller
->regs
[i
];
4575 clear_caller_saved_regs(env
, caller
->regs
);
4577 /* only increment it after check_reg_arg() finished */
4580 /* and go analyze first insn of the callee */
4581 *insn_idx
= target_insn
;
4583 if (env
->log
.level
& BPF_LOG_LEVEL
) {
4584 verbose(env
, "caller:\n");
4585 print_verifier_state(env
, caller
);
4586 verbose(env
, "callee:\n");
4587 print_verifier_state(env
, callee
);
4592 static int prepare_func_exit(struct bpf_verifier_env
*env
, int *insn_idx
)
4594 struct bpf_verifier_state
*state
= env
->cur_state
;
4595 struct bpf_func_state
*caller
, *callee
;
4596 struct bpf_reg_state
*r0
;
4599 callee
= state
->frame
[state
->curframe
];
4600 r0
= &callee
->regs
[BPF_REG_0
];
4601 if (r0
->type
== PTR_TO_STACK
) {
4602 /* technically it's ok to return caller's stack pointer
4603 * (or caller's caller's pointer) back to the caller,
4604 * since these pointers are valid. Only current stack
4605 * pointer will be invalid as soon as function exits,
4606 * but let's be conservative
4608 verbose(env
, "cannot return stack pointer to the caller\n");
4613 caller
= state
->frame
[state
->curframe
];
4614 /* return to the caller whatever r0 had in the callee */
4615 caller
->regs
[BPF_REG_0
] = *r0
;
4617 /* Transfer references to the caller */
4618 err
= transfer_reference_state(caller
, callee
);
4622 *insn_idx
= callee
->callsite
+ 1;
4623 if (env
->log
.level
& BPF_LOG_LEVEL
) {
4624 verbose(env
, "returning from callee:\n");
4625 print_verifier_state(env
, callee
);
4626 verbose(env
, "to caller at %d:\n", *insn_idx
);
4627 print_verifier_state(env
, caller
);
4629 /* clear everything in the callee */
4630 free_func_state(callee
);
4631 state
->frame
[state
->curframe
+ 1] = NULL
;
4635 static void do_refine_retval_range(struct bpf_reg_state
*regs
, int ret_type
,
4637 struct bpf_call_arg_meta
*meta
)
4639 struct bpf_reg_state
*ret_reg
= ®s
[BPF_REG_0
];
4641 if (ret_type
!= RET_INTEGER
||
4642 (func_id
!= BPF_FUNC_get_stack
&&
4643 func_id
!= BPF_FUNC_probe_read_str
&&
4644 func_id
!= BPF_FUNC_probe_read_kernel_str
&&
4645 func_id
!= BPF_FUNC_probe_read_user_str
))
4648 ret_reg
->smax_value
= meta
->msize_max_value
;
4649 ret_reg
->s32_max_value
= meta
->msize_max_value
;
4650 __reg_deduce_bounds(ret_reg
);
4651 __reg_bound_offset(ret_reg
);
4652 __update_reg_bounds(ret_reg
);
4656 record_func_map(struct bpf_verifier_env
*env
, struct bpf_call_arg_meta
*meta
,
4657 int func_id
, int insn_idx
)
4659 struct bpf_insn_aux_data
*aux
= &env
->insn_aux_data
[insn_idx
];
4660 struct bpf_map
*map
= meta
->map_ptr
;
4662 if (func_id
!= BPF_FUNC_tail_call
&&
4663 func_id
!= BPF_FUNC_map_lookup_elem
&&
4664 func_id
!= BPF_FUNC_map_update_elem
&&
4665 func_id
!= BPF_FUNC_map_delete_elem
&&
4666 func_id
!= BPF_FUNC_map_push_elem
&&
4667 func_id
!= BPF_FUNC_map_pop_elem
&&
4668 func_id
!= BPF_FUNC_map_peek_elem
)
4672 verbose(env
, "kernel subsystem misconfigured verifier\n");
4676 /* In case of read-only, some additional restrictions
4677 * need to be applied in order to prevent altering the
4678 * state of the map from program side.
4680 if ((map
->map_flags
& BPF_F_RDONLY_PROG
) &&
4681 (func_id
== BPF_FUNC_map_delete_elem
||
4682 func_id
== BPF_FUNC_map_update_elem
||
4683 func_id
== BPF_FUNC_map_push_elem
||
4684 func_id
== BPF_FUNC_map_pop_elem
)) {
4685 verbose(env
, "write into map forbidden\n");
4689 if (!BPF_MAP_PTR(aux
->map_ptr_state
))
4690 bpf_map_ptr_store(aux
, meta
->map_ptr
,
4691 !meta
->map_ptr
->bypass_spec_v1
);
4692 else if (BPF_MAP_PTR(aux
->map_ptr_state
) != meta
->map_ptr
)
4693 bpf_map_ptr_store(aux
, BPF_MAP_PTR_POISON
,
4694 !meta
->map_ptr
->bypass_spec_v1
);
4699 record_func_key(struct bpf_verifier_env
*env
, struct bpf_call_arg_meta
*meta
,
4700 int func_id
, int insn_idx
)
4702 struct bpf_insn_aux_data
*aux
= &env
->insn_aux_data
[insn_idx
];
4703 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
;
4704 struct bpf_map
*map
= meta
->map_ptr
;
4709 if (func_id
!= BPF_FUNC_tail_call
)
4711 if (!map
|| map
->map_type
!= BPF_MAP_TYPE_PROG_ARRAY
) {
4712 verbose(env
, "kernel subsystem misconfigured verifier\n");
4716 range
= tnum_range(0, map
->max_entries
- 1);
4717 reg
= ®s
[BPF_REG_3
];
4719 if (!register_is_const(reg
) || !tnum_in(range
, reg
->var_off
)) {
4720 bpf_map_key_store(aux
, BPF_MAP_KEY_POISON
);
4724 err
= mark_chain_precision(env
, BPF_REG_3
);
4728 val
= reg
->var_off
.value
;
4729 if (bpf_map_key_unseen(aux
))
4730 bpf_map_key_store(aux
, val
);
4731 else if (!bpf_map_key_poisoned(aux
) &&
4732 bpf_map_key_immediate(aux
) != val
)
4733 bpf_map_key_store(aux
, BPF_MAP_KEY_POISON
);
4737 static int check_reference_leak(struct bpf_verifier_env
*env
)
4739 struct bpf_func_state
*state
= cur_func(env
);
4742 for (i
= 0; i
< state
->acquired_refs
; i
++) {
4743 verbose(env
, "Unreleased reference id=%d alloc_insn=%d\n",
4744 state
->refs
[i
].id
, state
->refs
[i
].insn_idx
);
4746 return state
->acquired_refs
? -EINVAL
: 0;
4749 static int check_helper_call(struct bpf_verifier_env
*env
, int func_id
, int insn_idx
)
4751 const struct bpf_func_proto
*fn
= NULL
;
4752 struct bpf_reg_state
*regs
;
4753 struct bpf_call_arg_meta meta
;
4757 /* find function prototype */
4758 if (func_id
< 0 || func_id
>= __BPF_FUNC_MAX_ID
) {
4759 verbose(env
, "invalid func %s#%d\n", func_id_name(func_id
),
4764 if (env
->ops
->get_func_proto
)
4765 fn
= env
->ops
->get_func_proto(func_id
, env
->prog
);
4767 verbose(env
, "unknown func %s#%d\n", func_id_name(func_id
),
4772 /* eBPF programs must be GPL compatible to use GPL-ed functions */
4773 if (!env
->prog
->gpl_compatible
&& fn
->gpl_only
) {
4774 verbose(env
, "cannot call GPL-restricted function from non-GPL compatible program\n");
4778 /* With LD_ABS/IND some JITs save/restore skb from r1. */
4779 changes_data
= bpf_helper_changes_pkt_data(fn
->func
);
4780 if (changes_data
&& fn
->arg1_type
!= ARG_PTR_TO_CTX
) {
4781 verbose(env
, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
4782 func_id_name(func_id
), func_id
);
4786 memset(&meta
, 0, sizeof(meta
));
4787 meta
.pkt_access
= fn
->pkt_access
;
4789 err
= check_func_proto(fn
, func_id
);
4791 verbose(env
, "kernel subsystem misconfigured func %s#%d\n",
4792 func_id_name(func_id
), func_id
);
4796 meta
.func_id
= func_id
;
4798 for (i
= 0; i
< 5; i
++) {
4799 if (!fn
->check_btf_id
) {
4800 err
= btf_resolve_helper_id(&env
->log
, fn
, i
);
4804 err
= check_func_arg(env
, i
, &meta
, fn
);
4809 err
= record_func_map(env
, &meta
, func_id
, insn_idx
);
4813 err
= record_func_key(env
, &meta
, func_id
, insn_idx
);
4817 /* Mark slots with STACK_MISC in case of raw mode, stack offset
4818 * is inferred from register state.
4820 for (i
= 0; i
< meta
.access_size
; i
++) {
4821 err
= check_mem_access(env
, insn_idx
, meta
.regno
, i
, BPF_B
,
4822 BPF_WRITE
, -1, false);
4827 if (func_id
== BPF_FUNC_tail_call
) {
4828 err
= check_reference_leak(env
);
4830 verbose(env
, "tail_call would lead to reference leak\n");
4833 } else if (is_release_function(func_id
)) {
4834 err
= release_reference(env
, meta
.ref_obj_id
);
4836 verbose(env
, "func %s#%d reference has not been acquired before\n",
4837 func_id_name(func_id
), func_id
);
4842 regs
= cur_regs(env
);
4844 /* check that flags argument in get_local_storage(map, flags) is 0,
4845 * this is required because get_local_storage() can't return an error.
4847 if (func_id
== BPF_FUNC_get_local_storage
&&
4848 !register_is_null(®s
[BPF_REG_2
])) {
4849 verbose(env
, "get_local_storage() doesn't support non-zero flags\n");
4853 /* reset caller saved regs */
4854 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
4855 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
4856 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
4859 /* helper call returns 64-bit value. */
4860 regs
[BPF_REG_0
].subreg_def
= DEF_NOT_SUBREG
;
4862 /* update return register (already marked as written above) */
4863 if (fn
->ret_type
== RET_INTEGER
) {
4864 /* sets type to SCALAR_VALUE */
4865 mark_reg_unknown(env
, regs
, BPF_REG_0
);
4866 } else if (fn
->ret_type
== RET_VOID
) {
4867 regs
[BPF_REG_0
].type
= NOT_INIT
;
4868 } else if (fn
->ret_type
== RET_PTR_TO_MAP_VALUE_OR_NULL
||
4869 fn
->ret_type
== RET_PTR_TO_MAP_VALUE
) {
4870 /* There is no offset yet applied, variable or fixed */
4871 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
4872 /* remember map_ptr, so that check_map_access()
4873 * can check 'value_size' boundary of memory access
4874 * to map element returned from bpf_map_lookup_elem()
4876 if (meta
.map_ptr
== NULL
) {
4878 "kernel subsystem misconfigured verifier\n");
4881 regs
[BPF_REG_0
].map_ptr
= meta
.map_ptr
;
4882 if (fn
->ret_type
== RET_PTR_TO_MAP_VALUE
) {
4883 regs
[BPF_REG_0
].type
= PTR_TO_MAP_VALUE
;
4884 if (map_value_has_spin_lock(meta
.map_ptr
))
4885 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
4887 regs
[BPF_REG_0
].type
= PTR_TO_MAP_VALUE_OR_NULL
;
4888 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
4890 } else if (fn
->ret_type
== RET_PTR_TO_SOCKET_OR_NULL
) {
4891 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
4892 regs
[BPF_REG_0
].type
= PTR_TO_SOCKET_OR_NULL
;
4893 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
4894 } else if (fn
->ret_type
== RET_PTR_TO_SOCK_COMMON_OR_NULL
) {
4895 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
4896 regs
[BPF_REG_0
].type
= PTR_TO_SOCK_COMMON_OR_NULL
;
4897 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
4898 } else if (fn
->ret_type
== RET_PTR_TO_TCP_SOCK_OR_NULL
) {
4899 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
4900 regs
[BPF_REG_0
].type
= PTR_TO_TCP_SOCK_OR_NULL
;
4901 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
4902 } else if (fn
->ret_type
== RET_PTR_TO_ALLOC_MEM_OR_NULL
) {
4903 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
4904 regs
[BPF_REG_0
].type
= PTR_TO_MEM_OR_NULL
;
4905 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
4906 regs
[BPF_REG_0
].mem_size
= meta
.mem_size
;
4907 } else if (fn
->ret_type
== RET_PTR_TO_BTF_ID_OR_NULL
) {
4910 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
4911 regs
[BPF_REG_0
].type
= PTR_TO_BTF_ID_OR_NULL
;
4912 ret_btf_id
= *fn
->ret_btf_id
;
4913 if (ret_btf_id
== 0) {
4914 verbose(env
, "invalid return type %d of func %s#%d\n",
4915 fn
->ret_type
, func_id_name(func_id
), func_id
);
4918 regs
[BPF_REG_0
].btf_id
= ret_btf_id
;
4920 verbose(env
, "unknown return type %d of func %s#%d\n",
4921 fn
->ret_type
, func_id_name(func_id
), func_id
);
4925 if (is_ptr_cast_function(func_id
)) {
4926 /* For release_reference() */
4927 regs
[BPF_REG_0
].ref_obj_id
= meta
.ref_obj_id
;
4928 } else if (is_acquire_function(func_id
, meta
.map_ptr
)) {
4929 int id
= acquire_reference_state(env
, insn_idx
);
4933 /* For mark_ptr_or_null_reg() */
4934 regs
[BPF_REG_0
].id
= id
;
4935 /* For release_reference() */
4936 regs
[BPF_REG_0
].ref_obj_id
= id
;
4939 do_refine_retval_range(regs
, fn
->ret_type
, func_id
, &meta
);
4941 err
= check_map_func_compatibility(env
, meta
.map_ptr
, func_id
);
4945 if ((func_id
== BPF_FUNC_get_stack
||
4946 func_id
== BPF_FUNC_get_task_stack
) &&
4947 !env
->prog
->has_callchain_buf
) {
4948 const char *err_str
;
4950 #ifdef CONFIG_PERF_EVENTS
4951 err
= get_callchain_buffers(sysctl_perf_event_max_stack
);
4952 err_str
= "cannot get callchain buffer for func %s#%d\n";
4955 err_str
= "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
4958 verbose(env
, err_str
, func_id_name(func_id
), func_id
);
4962 env
->prog
->has_callchain_buf
= true;
4965 if (func_id
== BPF_FUNC_get_stackid
|| func_id
== BPF_FUNC_get_stack
)
4966 env
->prog
->call_get_stack
= true;
4969 clear_all_pkt_pointers(env
);
4973 static bool signed_add_overflows(s64 a
, s64 b
)
4975 /* Do the add in u64, where overflow is well-defined */
4976 s64 res
= (s64
)((u64
)a
+ (u64
)b
);
4983 static bool signed_add32_overflows(s64 a
, s64 b
)
4985 /* Do the add in u32, where overflow is well-defined */
4986 s32 res
= (s32
)((u32
)a
+ (u32
)b
);
4993 static bool signed_sub_overflows(s32 a
, s32 b
)
4995 /* Do the sub in u64, where overflow is well-defined */
4996 s64 res
= (s64
)((u64
)a
- (u64
)b
);
5003 static bool signed_sub32_overflows(s32 a
, s32 b
)
5005 /* Do the sub in u64, where overflow is well-defined */
5006 s32 res
= (s32
)((u32
)a
- (u32
)b
);
5013 static bool check_reg_sane_offset(struct bpf_verifier_env
*env
,
5014 const struct bpf_reg_state
*reg
,
5015 enum bpf_reg_type type
)
5017 bool known
= tnum_is_const(reg
->var_off
);
5018 s64 val
= reg
->var_off
.value
;
5019 s64 smin
= reg
->smin_value
;
5021 if (known
&& (val
>= BPF_MAX_VAR_OFF
|| val
<= -BPF_MAX_VAR_OFF
)) {
5022 verbose(env
, "math between %s pointer and %lld is not allowed\n",
5023 reg_type_str
[type
], val
);
5027 if (reg
->off
>= BPF_MAX_VAR_OFF
|| reg
->off
<= -BPF_MAX_VAR_OFF
) {
5028 verbose(env
, "%s pointer offset %d is not allowed\n",
5029 reg_type_str
[type
], reg
->off
);
5033 if (smin
== S64_MIN
) {
5034 verbose(env
, "math between %s pointer and register with unbounded min value is not allowed\n",
5035 reg_type_str
[type
]);
5039 if (smin
>= BPF_MAX_VAR_OFF
|| smin
<= -BPF_MAX_VAR_OFF
) {
5040 verbose(env
, "value %lld makes %s pointer be out of bounds\n",
5041 smin
, reg_type_str
[type
]);
5048 static struct bpf_insn_aux_data
*cur_aux(struct bpf_verifier_env
*env
)
5050 return &env
->insn_aux_data
[env
->insn_idx
];
5053 static int retrieve_ptr_limit(const struct bpf_reg_state
*ptr_reg
,
5054 u32
*ptr_limit
, u8 opcode
, bool off_is_neg
)
5056 bool mask_to_left
= (opcode
== BPF_ADD
&& off_is_neg
) ||
5057 (opcode
== BPF_SUB
&& !off_is_neg
);
5060 switch (ptr_reg
->type
) {
5062 /* Indirect variable offset stack access is prohibited in
5063 * unprivileged mode so it's not handled here.
5065 off
= ptr_reg
->off
+ ptr_reg
->var_off
.value
;
5067 *ptr_limit
= MAX_BPF_STACK
+ off
;
5071 case PTR_TO_MAP_VALUE
:
5073 *ptr_limit
= ptr_reg
->umax_value
+ ptr_reg
->off
;
5075 off
= ptr_reg
->smin_value
+ ptr_reg
->off
;
5076 *ptr_limit
= ptr_reg
->map_ptr
->value_size
- off
;
5084 static bool can_skip_alu_sanitation(const struct bpf_verifier_env
*env
,
5085 const struct bpf_insn
*insn
)
5087 return env
->bypass_spec_v1
|| BPF_SRC(insn
->code
) == BPF_K
;
5090 static int update_alu_sanitation_state(struct bpf_insn_aux_data
*aux
,
5091 u32 alu_state
, u32 alu_limit
)
5093 /* If we arrived here from different branches with different
5094 * state or limits to sanitize, then this won't work.
5096 if (aux
->alu_state
&&
5097 (aux
->alu_state
!= alu_state
||
5098 aux
->alu_limit
!= alu_limit
))
5101 /* Corresponding fixup done in fixup_bpf_calls(). */
5102 aux
->alu_state
= alu_state
;
5103 aux
->alu_limit
= alu_limit
;
5107 static int sanitize_val_alu(struct bpf_verifier_env
*env
,
5108 struct bpf_insn
*insn
)
5110 struct bpf_insn_aux_data
*aux
= cur_aux(env
);
5112 if (can_skip_alu_sanitation(env
, insn
))
5115 return update_alu_sanitation_state(aux
, BPF_ALU_NON_POINTER
, 0);
5118 static int sanitize_ptr_alu(struct bpf_verifier_env
*env
,
5119 struct bpf_insn
*insn
,
5120 const struct bpf_reg_state
*ptr_reg
,
5121 struct bpf_reg_state
*dst_reg
,
5124 struct bpf_verifier_state
*vstate
= env
->cur_state
;
5125 struct bpf_insn_aux_data
*aux
= cur_aux(env
);
5126 bool ptr_is_dst_reg
= ptr_reg
== dst_reg
;
5127 u8 opcode
= BPF_OP(insn
->code
);
5128 u32 alu_state
, alu_limit
;
5129 struct bpf_reg_state tmp
;
5132 if (can_skip_alu_sanitation(env
, insn
))
5135 /* We already marked aux for masking from non-speculative
5136 * paths, thus we got here in the first place. We only care
5137 * to explore bad access from here.
5139 if (vstate
->speculative
)
5142 alu_state
= off_is_neg
? BPF_ALU_NEG_VALUE
: 0;
5143 alu_state
|= ptr_is_dst_reg
?
5144 BPF_ALU_SANITIZE_SRC
: BPF_ALU_SANITIZE_DST
;
5146 if (retrieve_ptr_limit(ptr_reg
, &alu_limit
, opcode
, off_is_neg
))
5148 if (update_alu_sanitation_state(aux
, alu_state
, alu_limit
))
5151 /* Simulate and find potential out-of-bounds access under
5152 * speculative execution from truncation as a result of
5153 * masking when off was not within expected range. If off
5154 * sits in dst, then we temporarily need to move ptr there
5155 * to simulate dst (== 0) +/-= ptr. Needed, for example,
5156 * for cases where we use K-based arithmetic in one direction
5157 * and truncated reg-based in the other in order to explore
5160 if (!ptr_is_dst_reg
) {
5162 *dst_reg
= *ptr_reg
;
5164 ret
= push_stack(env
, env
->insn_idx
+ 1, env
->insn_idx
, true);
5165 if (!ptr_is_dst_reg
&& ret
)
5167 return !ret
? -EFAULT
: 0;
5170 /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
5171 * Caller should also handle BPF_MOV case separately.
5172 * If we return -EACCES, caller may want to try again treating pointer as a
5173 * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks.
5175 static int adjust_ptr_min_max_vals(struct bpf_verifier_env
*env
,
5176 struct bpf_insn
*insn
,
5177 const struct bpf_reg_state
*ptr_reg
,
5178 const struct bpf_reg_state
*off_reg
)
5180 struct bpf_verifier_state
*vstate
= env
->cur_state
;
5181 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
5182 struct bpf_reg_state
*regs
= state
->regs
, *dst_reg
;
5183 bool known
= tnum_is_const(off_reg
->var_off
);
5184 s64 smin_val
= off_reg
->smin_value
, smax_val
= off_reg
->smax_value
,
5185 smin_ptr
= ptr_reg
->smin_value
, smax_ptr
= ptr_reg
->smax_value
;
5186 u64 umin_val
= off_reg
->umin_value
, umax_val
= off_reg
->umax_value
,
5187 umin_ptr
= ptr_reg
->umin_value
, umax_ptr
= ptr_reg
->umax_value
;
5188 u32 dst
= insn
->dst_reg
, src
= insn
->src_reg
;
5189 u8 opcode
= BPF_OP(insn
->code
);
5192 dst_reg
= ®s
[dst
];
5194 if ((known
&& (smin_val
!= smax_val
|| umin_val
!= umax_val
)) ||
5195 smin_val
> smax_val
|| umin_val
> umax_val
) {
5196 /* Taint dst register if offset had invalid bounds derived from
5197 * e.g. dead branches.
5199 __mark_reg_unknown(env
, dst_reg
);
5203 if (BPF_CLASS(insn
->code
) != BPF_ALU64
) {
5204 /* 32-bit ALU ops on pointers produce (meaningless) scalars */
5205 if (opcode
== BPF_SUB
&& env
->allow_ptr_leaks
) {
5206 __mark_reg_unknown(env
, dst_reg
);
5211 "R%d 32-bit pointer arithmetic prohibited\n",
5216 switch (ptr_reg
->type
) {
5217 case PTR_TO_MAP_VALUE_OR_NULL
:
5218 verbose(env
, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
5219 dst
, reg_type_str
[ptr_reg
->type
]);
5221 case CONST_PTR_TO_MAP
:
5222 case PTR_TO_PACKET_END
:
5224 case PTR_TO_SOCKET_OR_NULL
:
5225 case PTR_TO_SOCK_COMMON
:
5226 case PTR_TO_SOCK_COMMON_OR_NULL
:
5227 case PTR_TO_TCP_SOCK
:
5228 case PTR_TO_TCP_SOCK_OR_NULL
:
5229 case PTR_TO_XDP_SOCK
:
5230 verbose(env
, "R%d pointer arithmetic on %s prohibited\n",
5231 dst
, reg_type_str
[ptr_reg
->type
]);
5233 case PTR_TO_MAP_VALUE
:
5234 if (!env
->allow_ptr_leaks
&& !known
&& (smin_val
< 0) != (smax_val
< 0)) {
5235 verbose(env
, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n",
5236 off_reg
== dst_reg
? dst
: src
);
5244 /* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
5245 * The id may be overwritten later if we create a new variable offset.
5247 dst_reg
->type
= ptr_reg
->type
;
5248 dst_reg
->id
= ptr_reg
->id
;
5250 if (!check_reg_sane_offset(env
, off_reg
, ptr_reg
->type
) ||
5251 !check_reg_sane_offset(env
, ptr_reg
, ptr_reg
->type
))
5254 /* pointer types do not carry 32-bit bounds at the moment. */
5255 __mark_reg32_unbounded(dst_reg
);
5259 ret
= sanitize_ptr_alu(env
, insn
, ptr_reg
, dst_reg
, smin_val
< 0);
5261 verbose(env
, "R%d tried to add from different maps or paths\n", dst
);
5264 /* We can take a fixed offset as long as it doesn't overflow
5265 * the s32 'off' field
5267 if (known
&& (ptr_reg
->off
+ smin_val
==
5268 (s64
)(s32
)(ptr_reg
->off
+ smin_val
))) {
5269 /* pointer += K. Accumulate it into fixed offset */
5270 dst_reg
->smin_value
= smin_ptr
;
5271 dst_reg
->smax_value
= smax_ptr
;
5272 dst_reg
->umin_value
= umin_ptr
;
5273 dst_reg
->umax_value
= umax_ptr
;
5274 dst_reg
->var_off
= ptr_reg
->var_off
;
5275 dst_reg
->off
= ptr_reg
->off
+ smin_val
;
5276 dst_reg
->raw
= ptr_reg
->raw
;
5279 /* A new variable offset is created. Note that off_reg->off
5280 * == 0, since it's a scalar.
5281 * dst_reg gets the pointer type and since some positive
5282 * integer value was added to the pointer, give it a new 'id'
5283 * if it's a PTR_TO_PACKET.
5284 * this creates a new 'base' pointer, off_reg (variable) gets
5285 * added into the variable offset, and we copy the fixed offset
5288 if (signed_add_overflows(smin_ptr
, smin_val
) ||
5289 signed_add_overflows(smax_ptr
, smax_val
)) {
5290 dst_reg
->smin_value
= S64_MIN
;
5291 dst_reg
->smax_value
= S64_MAX
;
5293 dst_reg
->smin_value
= smin_ptr
+ smin_val
;
5294 dst_reg
->smax_value
= smax_ptr
+ smax_val
;
5296 if (umin_ptr
+ umin_val
< umin_ptr
||
5297 umax_ptr
+ umax_val
< umax_ptr
) {
5298 dst_reg
->umin_value
= 0;
5299 dst_reg
->umax_value
= U64_MAX
;
5301 dst_reg
->umin_value
= umin_ptr
+ umin_val
;
5302 dst_reg
->umax_value
= umax_ptr
+ umax_val
;
5304 dst_reg
->var_off
= tnum_add(ptr_reg
->var_off
, off_reg
->var_off
);
5305 dst_reg
->off
= ptr_reg
->off
;
5306 dst_reg
->raw
= ptr_reg
->raw
;
5307 if (reg_is_pkt_pointer(ptr_reg
)) {
5308 dst_reg
->id
= ++env
->id_gen
;
5309 /* something was added to pkt_ptr, set range to zero */
5314 ret
= sanitize_ptr_alu(env
, insn
, ptr_reg
, dst_reg
, smin_val
< 0);
5316 verbose(env
, "R%d tried to sub from different maps or paths\n", dst
);
5319 if (dst_reg
== off_reg
) {
5320 /* scalar -= pointer. Creates an unknown scalar */
5321 verbose(env
, "R%d tried to subtract pointer from scalar\n",
5325 /* We don't allow subtraction from FP, because (according to
5326 * test_verifier.c test "invalid fp arithmetic", JITs might not
5327 * be able to deal with it.
5329 if (ptr_reg
->type
== PTR_TO_STACK
) {
5330 verbose(env
, "R%d subtraction from stack pointer prohibited\n",
5334 if (known
&& (ptr_reg
->off
- smin_val
==
5335 (s64
)(s32
)(ptr_reg
->off
- smin_val
))) {
5336 /* pointer -= K. Subtract it from fixed offset */
5337 dst_reg
->smin_value
= smin_ptr
;
5338 dst_reg
->smax_value
= smax_ptr
;
5339 dst_reg
->umin_value
= umin_ptr
;
5340 dst_reg
->umax_value
= umax_ptr
;
5341 dst_reg
->var_off
= ptr_reg
->var_off
;
5342 dst_reg
->id
= ptr_reg
->id
;
5343 dst_reg
->off
= ptr_reg
->off
- smin_val
;
5344 dst_reg
->raw
= ptr_reg
->raw
;
5347 /* A new variable offset is created. If the subtrahend is known
5348 * nonnegative, then any reg->range we had before is still good.
5350 if (signed_sub_overflows(smin_ptr
, smax_val
) ||
5351 signed_sub_overflows(smax_ptr
, smin_val
)) {
5352 /* Overflow possible, we know nothing */
5353 dst_reg
->smin_value
= S64_MIN
;
5354 dst_reg
->smax_value
= S64_MAX
;
5356 dst_reg
->smin_value
= smin_ptr
- smax_val
;
5357 dst_reg
->smax_value
= smax_ptr
- smin_val
;
5359 if (umin_ptr
< umax_val
) {
5360 /* Overflow possible, we know nothing */
5361 dst_reg
->umin_value
= 0;
5362 dst_reg
->umax_value
= U64_MAX
;
5364 /* Cannot overflow (as long as bounds are consistent) */
5365 dst_reg
->umin_value
= umin_ptr
- umax_val
;
5366 dst_reg
->umax_value
= umax_ptr
- umin_val
;
5368 dst_reg
->var_off
= tnum_sub(ptr_reg
->var_off
, off_reg
->var_off
);
5369 dst_reg
->off
= ptr_reg
->off
;
5370 dst_reg
->raw
= ptr_reg
->raw
;
5371 if (reg_is_pkt_pointer(ptr_reg
)) {
5372 dst_reg
->id
= ++env
->id_gen
;
5373 /* something was added to pkt_ptr, set range to zero */
5381 /* bitwise ops on pointers are troublesome, prohibit. */
5382 verbose(env
, "R%d bitwise operator %s on pointer prohibited\n",
5383 dst
, bpf_alu_string
[opcode
>> 4]);
5386 /* other operators (e.g. MUL,LSH) produce non-pointer results */
5387 verbose(env
, "R%d pointer arithmetic with %s operator prohibited\n",
5388 dst
, bpf_alu_string
[opcode
>> 4]);
5392 if (!check_reg_sane_offset(env
, dst_reg
, ptr_reg
->type
))
5395 __update_reg_bounds(dst_reg
);
5396 __reg_deduce_bounds(dst_reg
);
5397 __reg_bound_offset(dst_reg
);
5399 /* For unprivileged we require that resulting offset must be in bounds
5400 * in order to be able to sanitize access later on.
5402 if (!env
->bypass_spec_v1
) {
5403 if (dst_reg
->type
== PTR_TO_MAP_VALUE
&&
5404 check_map_access(env
, dst
, dst_reg
->off
, 1, false)) {
5405 verbose(env
, "R%d pointer arithmetic of map value goes out of range, "
5406 "prohibited for !root\n", dst
);
5408 } else if (dst_reg
->type
== PTR_TO_STACK
&&
5409 check_stack_access(env
, dst_reg
, dst_reg
->off
+
5410 dst_reg
->var_off
.value
, 1)) {
5411 verbose(env
, "R%d stack pointer arithmetic goes out of range, "
5412 "prohibited for !root\n", dst
);
5420 static void scalar32_min_max_add(struct bpf_reg_state
*dst_reg
,
5421 struct bpf_reg_state
*src_reg
)
5423 s32 smin_val
= src_reg
->s32_min_value
;
5424 s32 smax_val
= src_reg
->s32_max_value
;
5425 u32 umin_val
= src_reg
->u32_min_value
;
5426 u32 umax_val
= src_reg
->u32_max_value
;
5428 if (signed_add32_overflows(dst_reg
->s32_min_value
, smin_val
) ||
5429 signed_add32_overflows(dst_reg
->s32_max_value
, smax_val
)) {
5430 dst_reg
->s32_min_value
= S32_MIN
;
5431 dst_reg
->s32_max_value
= S32_MAX
;
5433 dst_reg
->s32_min_value
+= smin_val
;
5434 dst_reg
->s32_max_value
+= smax_val
;
5436 if (dst_reg
->u32_min_value
+ umin_val
< umin_val
||
5437 dst_reg
->u32_max_value
+ umax_val
< umax_val
) {
5438 dst_reg
->u32_min_value
= 0;
5439 dst_reg
->u32_max_value
= U32_MAX
;
5441 dst_reg
->u32_min_value
+= umin_val
;
5442 dst_reg
->u32_max_value
+= umax_val
;
5446 static void scalar_min_max_add(struct bpf_reg_state
*dst_reg
,
5447 struct bpf_reg_state
*src_reg
)
5449 s64 smin_val
= src_reg
->smin_value
;
5450 s64 smax_val
= src_reg
->smax_value
;
5451 u64 umin_val
= src_reg
->umin_value
;
5452 u64 umax_val
= src_reg
->umax_value
;
5454 if (signed_add_overflows(dst_reg
->smin_value
, smin_val
) ||
5455 signed_add_overflows(dst_reg
->smax_value
, smax_val
)) {
5456 dst_reg
->smin_value
= S64_MIN
;
5457 dst_reg
->smax_value
= S64_MAX
;
5459 dst_reg
->smin_value
+= smin_val
;
5460 dst_reg
->smax_value
+= smax_val
;
5462 if (dst_reg
->umin_value
+ umin_val
< umin_val
||
5463 dst_reg
->umax_value
+ umax_val
< umax_val
) {
5464 dst_reg
->umin_value
= 0;
5465 dst_reg
->umax_value
= U64_MAX
;
5467 dst_reg
->umin_value
+= umin_val
;
5468 dst_reg
->umax_value
+= umax_val
;
5472 static void scalar32_min_max_sub(struct bpf_reg_state
*dst_reg
,
5473 struct bpf_reg_state
*src_reg
)
5475 s32 smin_val
= src_reg
->s32_min_value
;
5476 s32 smax_val
= src_reg
->s32_max_value
;
5477 u32 umin_val
= src_reg
->u32_min_value
;
5478 u32 umax_val
= src_reg
->u32_max_value
;
5480 if (signed_sub32_overflows(dst_reg
->s32_min_value
, smax_val
) ||
5481 signed_sub32_overflows(dst_reg
->s32_max_value
, smin_val
)) {
5482 /* Overflow possible, we know nothing */
5483 dst_reg
->s32_min_value
= S32_MIN
;
5484 dst_reg
->s32_max_value
= S32_MAX
;
5486 dst_reg
->s32_min_value
-= smax_val
;
5487 dst_reg
->s32_max_value
-= smin_val
;
5489 if (dst_reg
->u32_min_value
< umax_val
) {
5490 /* Overflow possible, we know nothing */
5491 dst_reg
->u32_min_value
= 0;
5492 dst_reg
->u32_max_value
= U32_MAX
;
5494 /* Cannot overflow (as long as bounds are consistent) */
5495 dst_reg
->u32_min_value
-= umax_val
;
5496 dst_reg
->u32_max_value
-= umin_val
;
5500 static void scalar_min_max_sub(struct bpf_reg_state
*dst_reg
,
5501 struct bpf_reg_state
*src_reg
)
5503 s64 smin_val
= src_reg
->smin_value
;
5504 s64 smax_val
= src_reg
->smax_value
;
5505 u64 umin_val
= src_reg
->umin_value
;
5506 u64 umax_val
= src_reg
->umax_value
;
5508 if (signed_sub_overflows(dst_reg
->smin_value
, smax_val
) ||
5509 signed_sub_overflows(dst_reg
->smax_value
, smin_val
)) {
5510 /* Overflow possible, we know nothing */
5511 dst_reg
->smin_value
= S64_MIN
;
5512 dst_reg
->smax_value
= S64_MAX
;
5514 dst_reg
->smin_value
-= smax_val
;
5515 dst_reg
->smax_value
-= smin_val
;
5517 if (dst_reg
->umin_value
< umax_val
) {
5518 /* Overflow possible, we know nothing */
5519 dst_reg
->umin_value
= 0;
5520 dst_reg
->umax_value
= U64_MAX
;
5522 /* Cannot overflow (as long as bounds are consistent) */
5523 dst_reg
->umin_value
-= umax_val
;
5524 dst_reg
->umax_value
-= umin_val
;
5528 static void scalar32_min_max_mul(struct bpf_reg_state
*dst_reg
,
5529 struct bpf_reg_state
*src_reg
)
5531 s32 smin_val
= src_reg
->s32_min_value
;
5532 u32 umin_val
= src_reg
->u32_min_value
;
5533 u32 umax_val
= src_reg
->u32_max_value
;
5535 if (smin_val
< 0 || dst_reg
->s32_min_value
< 0) {
5536 /* Ain't nobody got time to multiply that sign */
5537 __mark_reg32_unbounded(dst_reg
);
5540 /* Both values are positive, so we can work with unsigned and
5541 * copy the result to signed (unless it exceeds S32_MAX).
5543 if (umax_val
> U16_MAX
|| dst_reg
->u32_max_value
> U16_MAX
) {
5544 /* Potential overflow, we know nothing */
5545 __mark_reg32_unbounded(dst_reg
);
5548 dst_reg
->u32_min_value
*= umin_val
;
5549 dst_reg
->u32_max_value
*= umax_val
;
5550 if (dst_reg
->u32_max_value
> S32_MAX
) {
5551 /* Overflow possible, we know nothing */
5552 dst_reg
->s32_min_value
= S32_MIN
;
5553 dst_reg
->s32_max_value
= S32_MAX
;
5555 dst_reg
->s32_min_value
= dst_reg
->u32_min_value
;
5556 dst_reg
->s32_max_value
= dst_reg
->u32_max_value
;
5560 static void scalar_min_max_mul(struct bpf_reg_state
*dst_reg
,
5561 struct bpf_reg_state
*src_reg
)
5563 s64 smin_val
= src_reg
->smin_value
;
5564 u64 umin_val
= src_reg
->umin_value
;
5565 u64 umax_val
= src_reg
->umax_value
;
5567 if (smin_val
< 0 || dst_reg
->smin_value
< 0) {
5568 /* Ain't nobody got time to multiply that sign */
5569 __mark_reg64_unbounded(dst_reg
);
5572 /* Both values are positive, so we can work with unsigned and
5573 * copy the result to signed (unless it exceeds S64_MAX).
5575 if (umax_val
> U32_MAX
|| dst_reg
->umax_value
> U32_MAX
) {
5576 /* Potential overflow, we know nothing */
5577 __mark_reg64_unbounded(dst_reg
);
5580 dst_reg
->umin_value
*= umin_val
;
5581 dst_reg
->umax_value
*= umax_val
;
5582 if (dst_reg
->umax_value
> S64_MAX
) {
5583 /* Overflow possible, we know nothing */
5584 dst_reg
->smin_value
= S64_MIN
;
5585 dst_reg
->smax_value
= S64_MAX
;
5587 dst_reg
->smin_value
= dst_reg
->umin_value
;
5588 dst_reg
->smax_value
= dst_reg
->umax_value
;
5592 static void scalar32_min_max_and(struct bpf_reg_state
*dst_reg
,
5593 struct bpf_reg_state
*src_reg
)
5595 bool src_known
= tnum_subreg_is_const(src_reg
->var_off
);
5596 bool dst_known
= tnum_subreg_is_const(dst_reg
->var_off
);
5597 struct tnum var32_off
= tnum_subreg(dst_reg
->var_off
);
5598 s32 smin_val
= src_reg
->s32_min_value
;
5599 u32 umax_val
= src_reg
->u32_max_value
;
5601 /* Assuming scalar64_min_max_and will be called so its safe
5602 * to skip updating register for known 32-bit case.
5604 if (src_known
&& dst_known
)
5607 /* We get our minimum from the var_off, since that's inherently
5608 * bitwise. Our maximum is the minimum of the operands' maxima.
5610 dst_reg
->u32_min_value
= var32_off
.value
;
5611 dst_reg
->u32_max_value
= min(dst_reg
->u32_max_value
, umax_val
);
5612 if (dst_reg
->s32_min_value
< 0 || smin_val
< 0) {
5613 /* Lose signed bounds when ANDing negative numbers,
5614 * ain't nobody got time for that.
5616 dst_reg
->s32_min_value
= S32_MIN
;
5617 dst_reg
->s32_max_value
= S32_MAX
;
5619 /* ANDing two positives gives a positive, so safe to
5620 * cast result into s64.
5622 dst_reg
->s32_min_value
= dst_reg
->u32_min_value
;
5623 dst_reg
->s32_max_value
= dst_reg
->u32_max_value
;
5628 static void scalar_min_max_and(struct bpf_reg_state
*dst_reg
,
5629 struct bpf_reg_state
*src_reg
)
5631 bool src_known
= tnum_is_const(src_reg
->var_off
);
5632 bool dst_known
= tnum_is_const(dst_reg
->var_off
);
5633 s64 smin_val
= src_reg
->smin_value
;
5634 u64 umax_val
= src_reg
->umax_value
;
5636 if (src_known
&& dst_known
) {
5637 __mark_reg_known(dst_reg
, dst_reg
->var_off
.value
&
5638 src_reg
->var_off
.value
);
5642 /* We get our minimum from the var_off, since that's inherently
5643 * bitwise. Our maximum is the minimum of the operands' maxima.
5645 dst_reg
->umin_value
= dst_reg
->var_off
.value
;
5646 dst_reg
->umax_value
= min(dst_reg
->umax_value
, umax_val
);
5647 if (dst_reg
->smin_value
< 0 || smin_val
< 0) {
5648 /* Lose signed bounds when ANDing negative numbers,
5649 * ain't nobody got time for that.
5651 dst_reg
->smin_value
= S64_MIN
;
5652 dst_reg
->smax_value
= S64_MAX
;
5654 /* ANDing two positives gives a positive, so safe to
5655 * cast result into s64.
5657 dst_reg
->smin_value
= dst_reg
->umin_value
;
5658 dst_reg
->smax_value
= dst_reg
->umax_value
;
5660 /* We may learn something more from the var_off */
5661 __update_reg_bounds(dst_reg
);
5664 static void scalar32_min_max_or(struct bpf_reg_state
*dst_reg
,
5665 struct bpf_reg_state
*src_reg
)
5667 bool src_known
= tnum_subreg_is_const(src_reg
->var_off
);
5668 bool dst_known
= tnum_subreg_is_const(dst_reg
->var_off
);
5669 struct tnum var32_off
= tnum_subreg(dst_reg
->var_off
);
5670 s32 smin_val
= src_reg
->smin_value
;
5671 u32 umin_val
= src_reg
->umin_value
;
5673 /* Assuming scalar64_min_max_or will be called so it is safe
5674 * to skip updating register for known case.
5676 if (src_known
&& dst_known
)
5679 /* We get our maximum from the var_off, and our minimum is the
5680 * maximum of the operands' minima
5682 dst_reg
->u32_min_value
= max(dst_reg
->u32_min_value
, umin_val
);
5683 dst_reg
->u32_max_value
= var32_off
.value
| var32_off
.mask
;
5684 if (dst_reg
->s32_min_value
< 0 || smin_val
< 0) {
5685 /* Lose signed bounds when ORing negative numbers,
5686 * ain't nobody got time for that.
5688 dst_reg
->s32_min_value
= S32_MIN
;
5689 dst_reg
->s32_max_value
= S32_MAX
;
5691 /* ORing two positives gives a positive, so safe to
5692 * cast result into s64.
5694 dst_reg
->s32_min_value
= dst_reg
->umin_value
;
5695 dst_reg
->s32_max_value
= dst_reg
->umax_value
;
5699 static void scalar_min_max_or(struct bpf_reg_state
*dst_reg
,
5700 struct bpf_reg_state
*src_reg
)
5702 bool src_known
= tnum_is_const(src_reg
->var_off
);
5703 bool dst_known
= tnum_is_const(dst_reg
->var_off
);
5704 s64 smin_val
= src_reg
->smin_value
;
5705 u64 umin_val
= src_reg
->umin_value
;
5707 if (src_known
&& dst_known
) {
5708 __mark_reg_known(dst_reg
, dst_reg
->var_off
.value
|
5709 src_reg
->var_off
.value
);
5713 /* We get our maximum from the var_off, and our minimum is the
5714 * maximum of the operands' minima
5716 dst_reg
->umin_value
= max(dst_reg
->umin_value
, umin_val
);
5717 dst_reg
->umax_value
= dst_reg
->var_off
.value
| dst_reg
->var_off
.mask
;
5718 if (dst_reg
->smin_value
< 0 || smin_val
< 0) {
5719 /* Lose signed bounds when ORing negative numbers,
5720 * ain't nobody got time for that.
5722 dst_reg
->smin_value
= S64_MIN
;
5723 dst_reg
->smax_value
= S64_MAX
;
5725 /* ORing two positives gives a positive, so safe to
5726 * cast result into s64.
5728 dst_reg
->smin_value
= dst_reg
->umin_value
;
5729 dst_reg
->smax_value
= dst_reg
->umax_value
;
5731 /* We may learn something more from the var_off */
5732 __update_reg_bounds(dst_reg
);
5735 static void __scalar32_min_max_lsh(struct bpf_reg_state
*dst_reg
,
5736 u64 umin_val
, u64 umax_val
)
5738 /* We lose all sign bit information (except what we can pick
5741 dst_reg
->s32_min_value
= S32_MIN
;
5742 dst_reg
->s32_max_value
= S32_MAX
;
5743 /* If we might shift our top bit out, then we know nothing */
5744 if (umax_val
> 31 || dst_reg
->u32_max_value
> 1ULL << (31 - umax_val
)) {
5745 dst_reg
->u32_min_value
= 0;
5746 dst_reg
->u32_max_value
= U32_MAX
;
5748 dst_reg
->u32_min_value
<<= umin_val
;
5749 dst_reg
->u32_max_value
<<= umax_val
;
5753 static void scalar32_min_max_lsh(struct bpf_reg_state
*dst_reg
,
5754 struct bpf_reg_state
*src_reg
)
5756 u32 umax_val
= src_reg
->u32_max_value
;
5757 u32 umin_val
= src_reg
->u32_min_value
;
5758 /* u32 alu operation will zext upper bits */
5759 struct tnum subreg
= tnum_subreg(dst_reg
->var_off
);
5761 __scalar32_min_max_lsh(dst_reg
, umin_val
, umax_val
);
5762 dst_reg
->var_off
= tnum_subreg(tnum_lshift(subreg
, umin_val
));
5763 /* Not required but being careful mark reg64 bounds as unknown so
5764 * that we are forced to pick them up from tnum and zext later and
5765 * if some path skips this step we are still safe.
5767 __mark_reg64_unbounded(dst_reg
);
5768 __update_reg32_bounds(dst_reg
);
5771 static void __scalar64_min_max_lsh(struct bpf_reg_state
*dst_reg
,
5772 u64 umin_val
, u64 umax_val
)
5774 /* Special case <<32 because it is a common compiler pattern to sign
5775 * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are
5776 * positive we know this shift will also be positive so we can track
5777 * bounds correctly. Otherwise we lose all sign bit information except
5778 * what we can pick up from var_off. Perhaps we can generalize this
5779 * later to shifts of any length.
5781 if (umin_val
== 32 && umax_val
== 32 && dst_reg
->s32_max_value
>= 0)
5782 dst_reg
->smax_value
= (s64
)dst_reg
->s32_max_value
<< 32;
5784 dst_reg
->smax_value
= S64_MAX
;
5786 if (umin_val
== 32 && umax_val
== 32 && dst_reg
->s32_min_value
>= 0)
5787 dst_reg
->smin_value
= (s64
)dst_reg
->s32_min_value
<< 32;
5789 dst_reg
->smin_value
= S64_MIN
;
5791 /* If we might shift our top bit out, then we know nothing */
5792 if (dst_reg
->umax_value
> 1ULL << (63 - umax_val
)) {
5793 dst_reg
->umin_value
= 0;
5794 dst_reg
->umax_value
= U64_MAX
;
5796 dst_reg
->umin_value
<<= umin_val
;
5797 dst_reg
->umax_value
<<= umax_val
;
5801 static void scalar_min_max_lsh(struct bpf_reg_state
*dst_reg
,
5802 struct bpf_reg_state
*src_reg
)
5804 u64 umax_val
= src_reg
->umax_value
;
5805 u64 umin_val
= src_reg
->umin_value
;
5807 /* scalar64 calc uses 32bit unshifted bounds so must be called first */
5808 __scalar64_min_max_lsh(dst_reg
, umin_val
, umax_val
);
5809 __scalar32_min_max_lsh(dst_reg
, umin_val
, umax_val
);
5811 dst_reg
->var_off
= tnum_lshift(dst_reg
->var_off
, umin_val
);
5812 /* We may learn something more from the var_off */
5813 __update_reg_bounds(dst_reg
);
5816 static void scalar32_min_max_rsh(struct bpf_reg_state
*dst_reg
,
5817 struct bpf_reg_state
*src_reg
)
5819 struct tnum subreg
= tnum_subreg(dst_reg
->var_off
);
5820 u32 umax_val
= src_reg
->u32_max_value
;
5821 u32 umin_val
= src_reg
->u32_min_value
;
5823 /* BPF_RSH is an unsigned shift. If the value in dst_reg might
5824 * be negative, then either:
5825 * 1) src_reg might be zero, so the sign bit of the result is
5826 * unknown, so we lose our signed bounds
5827 * 2) it's known negative, thus the unsigned bounds capture the
5829 * 3) the signed bounds cross zero, so they tell us nothing
5831 * If the value in dst_reg is known nonnegative, then again the
5832 * unsigned bounts capture the signed bounds.
5833 * Thus, in all cases it suffices to blow away our signed bounds
5834 * and rely on inferring new ones from the unsigned bounds and
5835 * var_off of the result.
5837 dst_reg
->s32_min_value
= S32_MIN
;
5838 dst_reg
->s32_max_value
= S32_MAX
;
5840 dst_reg
->var_off
= tnum_rshift(subreg
, umin_val
);
5841 dst_reg
->u32_min_value
>>= umax_val
;
5842 dst_reg
->u32_max_value
>>= umin_val
;
5844 __mark_reg64_unbounded(dst_reg
);
5845 __update_reg32_bounds(dst_reg
);
5848 static void scalar_min_max_rsh(struct bpf_reg_state
*dst_reg
,
5849 struct bpf_reg_state
*src_reg
)
5851 u64 umax_val
= src_reg
->umax_value
;
5852 u64 umin_val
= src_reg
->umin_value
;
5854 /* BPF_RSH is an unsigned shift. If the value in dst_reg might
5855 * be negative, then either:
5856 * 1) src_reg might be zero, so the sign bit of the result is
5857 * unknown, so we lose our signed bounds
5858 * 2) it's known negative, thus the unsigned bounds capture the
5860 * 3) the signed bounds cross zero, so they tell us nothing
5862 * If the value in dst_reg is known nonnegative, then again the
5863 * unsigned bounts capture the signed bounds.
5864 * Thus, in all cases it suffices to blow away our signed bounds
5865 * and rely on inferring new ones from the unsigned bounds and
5866 * var_off of the result.
5868 dst_reg
->smin_value
= S64_MIN
;
5869 dst_reg
->smax_value
= S64_MAX
;
5870 dst_reg
->var_off
= tnum_rshift(dst_reg
->var_off
, umin_val
);
5871 dst_reg
->umin_value
>>= umax_val
;
5872 dst_reg
->umax_value
>>= umin_val
;
5874 /* Its not easy to operate on alu32 bounds here because it depends
5875 * on bits being shifted in. Take easy way out and mark unbounded
5876 * so we can recalculate later from tnum.
5878 __mark_reg32_unbounded(dst_reg
);
5879 __update_reg_bounds(dst_reg
);
5882 static void scalar32_min_max_arsh(struct bpf_reg_state
*dst_reg
,
5883 struct bpf_reg_state
*src_reg
)
5885 u64 umin_val
= src_reg
->u32_min_value
;
5887 /* Upon reaching here, src_known is true and
5888 * umax_val is equal to umin_val.
5890 dst_reg
->s32_min_value
= (u32
)(((s32
)dst_reg
->s32_min_value
) >> umin_val
);
5891 dst_reg
->s32_max_value
= (u32
)(((s32
)dst_reg
->s32_max_value
) >> umin_val
);
5893 dst_reg
->var_off
= tnum_arshift(tnum_subreg(dst_reg
->var_off
), umin_val
, 32);
5895 /* blow away the dst_reg umin_value/umax_value and rely on
5896 * dst_reg var_off to refine the result.
5898 dst_reg
->u32_min_value
= 0;
5899 dst_reg
->u32_max_value
= U32_MAX
;
5901 __mark_reg64_unbounded(dst_reg
);
5902 __update_reg32_bounds(dst_reg
);
5905 static void scalar_min_max_arsh(struct bpf_reg_state
*dst_reg
,
5906 struct bpf_reg_state
*src_reg
)
5908 u64 umin_val
= src_reg
->umin_value
;
5910 /* Upon reaching here, src_known is true and umax_val is equal
5913 dst_reg
->smin_value
>>= umin_val
;
5914 dst_reg
->smax_value
>>= umin_val
;
5916 dst_reg
->var_off
= tnum_arshift(dst_reg
->var_off
, umin_val
, 64);
5918 /* blow away the dst_reg umin_value/umax_value and rely on
5919 * dst_reg var_off to refine the result.
5921 dst_reg
->umin_value
= 0;
5922 dst_reg
->umax_value
= U64_MAX
;
5924 /* Its not easy to operate on alu32 bounds here because it depends
5925 * on bits being shifted in from upper 32-bits. Take easy way out
5926 * and mark unbounded so we can recalculate later from tnum.
5928 __mark_reg32_unbounded(dst_reg
);
5929 __update_reg_bounds(dst_reg
);
5932 /* WARNING: This function does calculations on 64-bit values, but the actual
5933 * execution may occur on 32-bit values. Therefore, things like bitshifts
5934 * need extra checks in the 32-bit case.
5936 static int adjust_scalar_min_max_vals(struct bpf_verifier_env
*env
,
5937 struct bpf_insn
*insn
,
5938 struct bpf_reg_state
*dst_reg
,
5939 struct bpf_reg_state src_reg
)
5941 struct bpf_reg_state
*regs
= cur_regs(env
);
5942 u8 opcode
= BPF_OP(insn
->code
);
5944 s64 smin_val
, smax_val
;
5945 u64 umin_val
, umax_val
;
5946 s32 s32_min_val
, s32_max_val
;
5947 u32 u32_min_val
, u32_max_val
;
5948 u64 insn_bitness
= (BPF_CLASS(insn
->code
) == BPF_ALU64
) ? 64 : 32;
5949 u32 dst
= insn
->dst_reg
;
5951 bool alu32
= (BPF_CLASS(insn
->code
) != BPF_ALU64
);
5953 smin_val
= src_reg
.smin_value
;
5954 smax_val
= src_reg
.smax_value
;
5955 umin_val
= src_reg
.umin_value
;
5956 umax_val
= src_reg
.umax_value
;
5958 s32_min_val
= src_reg
.s32_min_value
;
5959 s32_max_val
= src_reg
.s32_max_value
;
5960 u32_min_val
= src_reg
.u32_min_value
;
5961 u32_max_val
= src_reg
.u32_max_value
;
5964 src_known
= tnum_subreg_is_const(src_reg
.var_off
);
5966 (s32_min_val
!= s32_max_val
|| u32_min_val
!= u32_max_val
)) ||
5967 s32_min_val
> s32_max_val
|| u32_min_val
> u32_max_val
) {
5968 /* Taint dst register if offset had invalid bounds
5969 * derived from e.g. dead branches.
5971 __mark_reg_unknown(env
, dst_reg
);
5975 src_known
= tnum_is_const(src_reg
.var_off
);
5977 (smin_val
!= smax_val
|| umin_val
!= umax_val
)) ||
5978 smin_val
> smax_val
|| umin_val
> umax_val
) {
5979 /* Taint dst register if offset had invalid bounds
5980 * derived from e.g. dead branches.
5982 __mark_reg_unknown(env
, dst_reg
);
5988 opcode
!= BPF_ADD
&& opcode
!= BPF_SUB
&& opcode
!= BPF_AND
) {
5989 __mark_reg_unknown(env
, dst_reg
);
5993 /* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops.
5994 * There are two classes of instructions: The first class we track both
5995 * alu32 and alu64 sign/unsigned bounds independently this provides the
5996 * greatest amount of precision when alu operations are mixed with jmp32
5997 * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD,
5998 * and BPF_OR. This is possible because these ops have fairly easy to
5999 * understand and calculate behavior in both 32-bit and 64-bit alu ops.
6000 * See alu32 verifier tests for examples. The second class of
6001 * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy
6002 * with regards to tracking sign/unsigned bounds because the bits may
6003 * cross subreg boundaries in the alu64 case. When this happens we mark
6004 * the reg unbounded in the subreg bound space and use the resulting
6005 * tnum to calculate an approximation of the sign/unsigned bounds.
6009 ret
= sanitize_val_alu(env
, insn
);
6011 verbose(env
, "R%d tried to add from different pointers or scalars\n", dst
);
6014 scalar32_min_max_add(dst_reg
, &src_reg
);
6015 scalar_min_max_add(dst_reg
, &src_reg
);
6016 dst_reg
->var_off
= tnum_add(dst_reg
->var_off
, src_reg
.var_off
);
6019 ret
= sanitize_val_alu(env
, insn
);
6021 verbose(env
, "R%d tried to sub from different pointers or scalars\n", dst
);
6024 scalar32_min_max_sub(dst_reg
, &src_reg
);
6025 scalar_min_max_sub(dst_reg
, &src_reg
);
6026 dst_reg
->var_off
= tnum_sub(dst_reg
->var_off
, src_reg
.var_off
);
6029 dst_reg
->var_off
= tnum_mul(dst_reg
->var_off
, src_reg
.var_off
);
6030 scalar32_min_max_mul(dst_reg
, &src_reg
);
6031 scalar_min_max_mul(dst_reg
, &src_reg
);
6034 dst_reg
->var_off
= tnum_and(dst_reg
->var_off
, src_reg
.var_off
);
6035 scalar32_min_max_and(dst_reg
, &src_reg
);
6036 scalar_min_max_and(dst_reg
, &src_reg
);
6039 dst_reg
->var_off
= tnum_or(dst_reg
->var_off
, src_reg
.var_off
);
6040 scalar32_min_max_or(dst_reg
, &src_reg
);
6041 scalar_min_max_or(dst_reg
, &src_reg
);
6044 if (umax_val
>= insn_bitness
) {
6045 /* Shifts greater than 31 or 63 are undefined.
6046 * This includes shifts by a negative number.
6048 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
6052 scalar32_min_max_lsh(dst_reg
, &src_reg
);
6054 scalar_min_max_lsh(dst_reg
, &src_reg
);
6057 if (umax_val
>= insn_bitness
) {
6058 /* Shifts greater than 31 or 63 are undefined.
6059 * This includes shifts by a negative number.
6061 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
6065 scalar32_min_max_rsh(dst_reg
, &src_reg
);
6067 scalar_min_max_rsh(dst_reg
, &src_reg
);
6070 if (umax_val
>= insn_bitness
) {
6071 /* Shifts greater than 31 or 63 are undefined.
6072 * This includes shifts by a negative number.
6074 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
6078 scalar32_min_max_arsh(dst_reg
, &src_reg
);
6080 scalar_min_max_arsh(dst_reg
, &src_reg
);
6083 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
6087 /* ALU32 ops are zero extended into 64bit register */
6089 zext_32_to_64(dst_reg
);
6091 __update_reg_bounds(dst_reg
);
6092 __reg_deduce_bounds(dst_reg
);
6093 __reg_bound_offset(dst_reg
);
6097 /* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max
6100 static int adjust_reg_min_max_vals(struct bpf_verifier_env
*env
,
6101 struct bpf_insn
*insn
)
6103 struct bpf_verifier_state
*vstate
= env
->cur_state
;
6104 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
6105 struct bpf_reg_state
*regs
= state
->regs
, *dst_reg
, *src_reg
;
6106 struct bpf_reg_state
*ptr_reg
= NULL
, off_reg
= {0};
6107 u8 opcode
= BPF_OP(insn
->code
);
6110 dst_reg
= ®s
[insn
->dst_reg
];
6112 if (dst_reg
->type
!= SCALAR_VALUE
)
6114 if (BPF_SRC(insn
->code
) == BPF_X
) {
6115 src_reg
= ®s
[insn
->src_reg
];
6116 if (src_reg
->type
!= SCALAR_VALUE
) {
6117 if (dst_reg
->type
!= SCALAR_VALUE
) {
6118 /* Combining two pointers by any ALU op yields
6119 * an arbitrary scalar. Disallow all math except
6120 * pointer subtraction
6122 if (opcode
== BPF_SUB
&& env
->allow_ptr_leaks
) {
6123 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
6126 verbose(env
, "R%d pointer %s pointer prohibited\n",
6128 bpf_alu_string
[opcode
>> 4]);
6131 /* scalar += pointer
6132 * This is legal, but we have to reverse our
6133 * src/dest handling in computing the range
6135 err
= mark_chain_precision(env
, insn
->dst_reg
);
6138 return adjust_ptr_min_max_vals(env
, insn
,
6141 } else if (ptr_reg
) {
6142 /* pointer += scalar */
6143 err
= mark_chain_precision(env
, insn
->src_reg
);
6146 return adjust_ptr_min_max_vals(env
, insn
,
6150 /* Pretend the src is a reg with a known value, since we only
6151 * need to be able to read from this state.
6153 off_reg
.type
= SCALAR_VALUE
;
6154 __mark_reg_known(&off_reg
, insn
->imm
);
6156 if (ptr_reg
) /* pointer += K */
6157 return adjust_ptr_min_max_vals(env
, insn
,
6161 /* Got here implies adding two SCALAR_VALUEs */
6162 if (WARN_ON_ONCE(ptr_reg
)) {
6163 print_verifier_state(env
, state
);
6164 verbose(env
, "verifier internal error: unexpected ptr_reg\n");
6167 if (WARN_ON(!src_reg
)) {
6168 print_verifier_state(env
, state
);
6169 verbose(env
, "verifier internal error: no src_reg\n");
6172 return adjust_scalar_min_max_vals(env
, insn
, dst_reg
, *src_reg
);
6175 /* check validity of 32-bit and 64-bit arithmetic operations */
6176 static int check_alu_op(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
6178 struct bpf_reg_state
*regs
= cur_regs(env
);
6179 u8 opcode
= BPF_OP(insn
->code
);
6182 if (opcode
== BPF_END
|| opcode
== BPF_NEG
) {
6183 if (opcode
== BPF_NEG
) {
6184 if (BPF_SRC(insn
->code
) != 0 ||
6185 insn
->src_reg
!= BPF_REG_0
||
6186 insn
->off
!= 0 || insn
->imm
!= 0) {
6187 verbose(env
, "BPF_NEG uses reserved fields\n");
6191 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0 ||
6192 (insn
->imm
!= 16 && insn
->imm
!= 32 && insn
->imm
!= 64) ||
6193 BPF_CLASS(insn
->code
) == BPF_ALU64
) {
6194 verbose(env
, "BPF_END uses reserved fields\n");
6199 /* check src operand */
6200 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
6204 if (is_pointer_value(env
, insn
->dst_reg
)) {
6205 verbose(env
, "R%d pointer arithmetic prohibited\n",
6210 /* check dest operand */
6211 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP
);
6215 } else if (opcode
== BPF_MOV
) {
6217 if (BPF_SRC(insn
->code
) == BPF_X
) {
6218 if (insn
->imm
!= 0 || insn
->off
!= 0) {
6219 verbose(env
, "BPF_MOV uses reserved fields\n");
6223 /* check src operand */
6224 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
6228 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0) {
6229 verbose(env
, "BPF_MOV uses reserved fields\n");
6234 /* check dest operand, mark as required later */
6235 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
6239 if (BPF_SRC(insn
->code
) == BPF_X
) {
6240 struct bpf_reg_state
*src_reg
= regs
+ insn
->src_reg
;
6241 struct bpf_reg_state
*dst_reg
= regs
+ insn
->dst_reg
;
6243 if (BPF_CLASS(insn
->code
) == BPF_ALU64
) {
6245 * copy register state to dest reg
6247 *dst_reg
= *src_reg
;
6248 dst_reg
->live
|= REG_LIVE_WRITTEN
;
6249 dst_reg
->subreg_def
= DEF_NOT_SUBREG
;
6252 if (is_pointer_value(env
, insn
->src_reg
)) {
6254 "R%d partial copy of pointer\n",
6257 } else if (src_reg
->type
== SCALAR_VALUE
) {
6258 *dst_reg
= *src_reg
;
6259 dst_reg
->live
|= REG_LIVE_WRITTEN
;
6260 dst_reg
->subreg_def
= env
->insn_idx
+ 1;
6262 mark_reg_unknown(env
, regs
,
6265 zext_32_to_64(dst_reg
);
6269 * remember the value we stored into this reg
6271 /* clear any state __mark_reg_known doesn't set */
6272 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
6273 regs
[insn
->dst_reg
].type
= SCALAR_VALUE
;
6274 if (BPF_CLASS(insn
->code
) == BPF_ALU64
) {
6275 __mark_reg_known(regs
+ insn
->dst_reg
,
6278 __mark_reg_known(regs
+ insn
->dst_reg
,
6283 } else if (opcode
> BPF_END
) {
6284 verbose(env
, "invalid BPF_ALU opcode %x\n", opcode
);
6287 } else { /* all other ALU ops: and, sub, xor, add, ... */
6289 if (BPF_SRC(insn
->code
) == BPF_X
) {
6290 if (insn
->imm
!= 0 || insn
->off
!= 0) {
6291 verbose(env
, "BPF_ALU uses reserved fields\n");
6294 /* check src1 operand */
6295 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
6299 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0) {
6300 verbose(env
, "BPF_ALU uses reserved fields\n");
6305 /* check src2 operand */
6306 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
6310 if ((opcode
== BPF_MOD
|| opcode
== BPF_DIV
) &&
6311 BPF_SRC(insn
->code
) == BPF_K
&& insn
->imm
== 0) {
6312 verbose(env
, "div by zero\n");
6316 if ((opcode
== BPF_LSH
|| opcode
== BPF_RSH
||
6317 opcode
== BPF_ARSH
) && BPF_SRC(insn
->code
) == BPF_K
) {
6318 int size
= BPF_CLASS(insn
->code
) == BPF_ALU64
? 64 : 32;
6320 if (insn
->imm
< 0 || insn
->imm
>= size
) {
6321 verbose(env
, "invalid shift %d\n", insn
->imm
);
6326 /* check dest operand */
6327 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
6331 return adjust_reg_min_max_vals(env
, insn
);
6337 static void __find_good_pkt_pointers(struct bpf_func_state
*state
,
6338 struct bpf_reg_state
*dst_reg
,
6339 enum bpf_reg_type type
, u16 new_range
)
6341 struct bpf_reg_state
*reg
;
6344 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
6345 reg
= &state
->regs
[i
];
6346 if (reg
->type
== type
&& reg
->id
== dst_reg
->id
)
6347 /* keep the maximum range already checked */
6348 reg
->range
= max(reg
->range
, new_range
);
6351 bpf_for_each_spilled_reg(i
, state
, reg
) {
6354 if (reg
->type
== type
&& reg
->id
== dst_reg
->id
)
6355 reg
->range
= max(reg
->range
, new_range
);
6359 static void find_good_pkt_pointers(struct bpf_verifier_state
*vstate
,
6360 struct bpf_reg_state
*dst_reg
,
6361 enum bpf_reg_type type
,
6362 bool range_right_open
)
6367 if (dst_reg
->off
< 0 ||
6368 (dst_reg
->off
== 0 && range_right_open
))
6369 /* This doesn't give us any range */
6372 if (dst_reg
->umax_value
> MAX_PACKET_OFF
||
6373 dst_reg
->umax_value
+ dst_reg
->off
> MAX_PACKET_OFF
)
6374 /* Risk of overflow. For instance, ptr + (1<<63) may be less
6375 * than pkt_end, but that's because it's also less than pkt.
6379 new_range
= dst_reg
->off
;
6380 if (range_right_open
)
6383 /* Examples for register markings:
6385 * pkt_data in dst register:
6389 * if (r2 > pkt_end) goto <handle exception>
6394 * if (r2 < pkt_end) goto <access okay>
6395 * <handle exception>
6398 * r2 == dst_reg, pkt_end == src_reg
6399 * r2=pkt(id=n,off=8,r=0)
6400 * r3=pkt(id=n,off=0,r=0)
6402 * pkt_data in src register:
6406 * if (pkt_end >= r2) goto <access okay>
6407 * <handle exception>
6411 * if (pkt_end <= r2) goto <handle exception>
6415 * pkt_end == dst_reg, r2 == src_reg
6416 * r2=pkt(id=n,off=8,r=0)
6417 * r3=pkt(id=n,off=0,r=0)
6419 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
6420 * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
6421 * and [r3, r3 + 8-1) respectively is safe to access depending on
6425 /* If our ids match, then we must have the same max_value. And we
6426 * don't care about the other reg's fixed offset, since if it's too big
6427 * the range won't allow anything.
6428 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
6430 for (i
= 0; i
<= vstate
->curframe
; i
++)
6431 __find_good_pkt_pointers(vstate
->frame
[i
], dst_reg
, type
,
6435 static int is_branch32_taken(struct bpf_reg_state
*reg
, u32 val
, u8 opcode
)
6437 struct tnum subreg
= tnum_subreg(reg
->var_off
);
6438 s32 sval
= (s32
)val
;
6442 if (tnum_is_const(subreg
))
6443 return !!tnum_equals_const(subreg
, val
);
6446 if (tnum_is_const(subreg
))
6447 return !tnum_equals_const(subreg
, val
);
6450 if ((~subreg
.mask
& subreg
.value
) & val
)
6452 if (!((subreg
.mask
| subreg
.value
) & val
))
6456 if (reg
->u32_min_value
> val
)
6458 else if (reg
->u32_max_value
<= val
)
6462 if (reg
->s32_min_value
> sval
)
6464 else if (reg
->s32_max_value
< sval
)
6468 if (reg
->u32_max_value
< val
)
6470 else if (reg
->u32_min_value
>= val
)
6474 if (reg
->s32_max_value
< sval
)
6476 else if (reg
->s32_min_value
>= sval
)
6480 if (reg
->u32_min_value
>= val
)
6482 else if (reg
->u32_max_value
< val
)
6486 if (reg
->s32_min_value
>= sval
)
6488 else if (reg
->s32_max_value
< sval
)
6492 if (reg
->u32_max_value
<= val
)
6494 else if (reg
->u32_min_value
> val
)
6498 if (reg
->s32_max_value
<= sval
)
6500 else if (reg
->s32_min_value
> sval
)
6509 static int is_branch64_taken(struct bpf_reg_state
*reg
, u64 val
, u8 opcode
)
6511 s64 sval
= (s64
)val
;
6515 if (tnum_is_const(reg
->var_off
))
6516 return !!tnum_equals_const(reg
->var_off
, val
);
6519 if (tnum_is_const(reg
->var_off
))
6520 return !tnum_equals_const(reg
->var_off
, val
);
6523 if ((~reg
->var_off
.mask
& reg
->var_off
.value
) & val
)
6525 if (!((reg
->var_off
.mask
| reg
->var_off
.value
) & val
))
6529 if (reg
->umin_value
> val
)
6531 else if (reg
->umax_value
<= val
)
6535 if (reg
->smin_value
> sval
)
6537 else if (reg
->smax_value
< sval
)
6541 if (reg
->umax_value
< val
)
6543 else if (reg
->umin_value
>= val
)
6547 if (reg
->smax_value
< sval
)
6549 else if (reg
->smin_value
>= sval
)
6553 if (reg
->umin_value
>= val
)
6555 else if (reg
->umax_value
< val
)
6559 if (reg
->smin_value
>= sval
)
6561 else if (reg
->smax_value
< sval
)
6565 if (reg
->umax_value
<= val
)
6567 else if (reg
->umin_value
> val
)
6571 if (reg
->smax_value
<= sval
)
6573 else if (reg
->smin_value
> sval
)
6581 /* compute branch direction of the expression "if (reg opcode val) goto target;"
6583 * 1 - branch will be taken and "goto target" will be executed
6584 * 0 - branch will not be taken and fall-through to next insn
6585 * -1 - unknown. Example: "if (reg < 5)" is unknown when register value
6588 static int is_branch_taken(struct bpf_reg_state
*reg
, u64 val
, u8 opcode
,
6591 if (__is_pointer_value(false, reg
)) {
6592 if (!reg_type_not_null(reg
->type
))
6595 /* If pointer is valid tests against zero will fail so we can
6596 * use this to direct branch taken.
6612 return is_branch32_taken(reg
, val
, opcode
);
6613 return is_branch64_taken(reg
, val
, opcode
);
6616 /* Adjusts the register min/max values in the case that the dst_reg is the
6617 * variable register that we are working on, and src_reg is a constant or we're
6618 * simply doing a BPF_K check.
6619 * In JEQ/JNE cases we also adjust the var_off values.
6621 static void reg_set_min_max(struct bpf_reg_state
*true_reg
,
6622 struct bpf_reg_state
*false_reg
,
6624 u8 opcode
, bool is_jmp32
)
6626 struct tnum false_32off
= tnum_subreg(false_reg
->var_off
);
6627 struct tnum false_64off
= false_reg
->var_off
;
6628 struct tnum true_32off
= tnum_subreg(true_reg
->var_off
);
6629 struct tnum true_64off
= true_reg
->var_off
;
6630 s64 sval
= (s64
)val
;
6631 s32 sval32
= (s32
)val32
;
6633 /* If the dst_reg is a pointer, we can't learn anything about its
6634 * variable offset from the compare (unless src_reg were a pointer into
6635 * the same object, but we don't bother with that.
6636 * Since false_reg and true_reg have the same type by construction, we
6637 * only need to check one of them for pointerness.
6639 if (__is_pointer_value(false, false_reg
))
6646 struct bpf_reg_state
*reg
=
6647 opcode
== BPF_JEQ
? true_reg
: false_reg
;
6649 /* For BPF_JEQ, if this is false we know nothing Jon Snow, but
6650 * if it is true we know the value for sure. Likewise for
6654 __mark_reg32_known(reg
, val32
);
6656 __mark_reg_known(reg
, val
);
6661 false_32off
= tnum_and(false_32off
, tnum_const(~val32
));
6662 if (is_power_of_2(val32
))
6663 true_32off
= tnum_or(true_32off
,
6666 false_64off
= tnum_and(false_64off
, tnum_const(~val
));
6667 if (is_power_of_2(val
))
6668 true_64off
= tnum_or(true_64off
,
6676 u32 false_umax
= opcode
== BPF_JGT
? val32
: val32
- 1;
6677 u32 true_umin
= opcode
== BPF_JGT
? val32
+ 1 : val32
;
6679 false_reg
->u32_max_value
= min(false_reg
->u32_max_value
,
6681 true_reg
->u32_min_value
= max(true_reg
->u32_min_value
,
6684 u64 false_umax
= opcode
== BPF_JGT
? val
: val
- 1;
6685 u64 true_umin
= opcode
== BPF_JGT
? val
+ 1 : val
;
6687 false_reg
->umax_value
= min(false_reg
->umax_value
, false_umax
);
6688 true_reg
->umin_value
= max(true_reg
->umin_value
, true_umin
);
6696 s32 false_smax
= opcode
== BPF_JSGT
? sval32
: sval32
- 1;
6697 s32 true_smin
= opcode
== BPF_JSGT
? sval32
+ 1 : sval32
;
6699 false_reg
->s32_max_value
= min(false_reg
->s32_max_value
, false_smax
);
6700 true_reg
->s32_min_value
= max(true_reg
->s32_min_value
, true_smin
);
6702 s64 false_smax
= opcode
== BPF_JSGT
? sval
: sval
- 1;
6703 s64 true_smin
= opcode
== BPF_JSGT
? sval
+ 1 : sval
;
6705 false_reg
->smax_value
= min(false_reg
->smax_value
, false_smax
);
6706 true_reg
->smin_value
= max(true_reg
->smin_value
, true_smin
);
6714 u32 false_umin
= opcode
== BPF_JLT
? val32
: val32
+ 1;
6715 u32 true_umax
= opcode
== BPF_JLT
? val32
- 1 : val32
;
6717 false_reg
->u32_min_value
= max(false_reg
->u32_min_value
,
6719 true_reg
->u32_max_value
= min(true_reg
->u32_max_value
,
6722 u64 false_umin
= opcode
== BPF_JLT
? val
: val
+ 1;
6723 u64 true_umax
= opcode
== BPF_JLT
? val
- 1 : val
;
6725 false_reg
->umin_value
= max(false_reg
->umin_value
, false_umin
);
6726 true_reg
->umax_value
= min(true_reg
->umax_value
, true_umax
);
6734 s32 false_smin
= opcode
== BPF_JSLT
? sval32
: sval32
+ 1;
6735 s32 true_smax
= opcode
== BPF_JSLT
? sval32
- 1 : sval32
;
6737 false_reg
->s32_min_value
= max(false_reg
->s32_min_value
, false_smin
);
6738 true_reg
->s32_max_value
= min(true_reg
->s32_max_value
, true_smax
);
6740 s64 false_smin
= opcode
== BPF_JSLT
? sval
: sval
+ 1;
6741 s64 true_smax
= opcode
== BPF_JSLT
? sval
- 1 : sval
;
6743 false_reg
->smin_value
= max(false_reg
->smin_value
, false_smin
);
6744 true_reg
->smax_value
= min(true_reg
->smax_value
, true_smax
);
6753 false_reg
->var_off
= tnum_or(tnum_clear_subreg(false_64off
),
6754 tnum_subreg(false_32off
));
6755 true_reg
->var_off
= tnum_or(tnum_clear_subreg(true_64off
),
6756 tnum_subreg(true_32off
));
6757 __reg_combine_32_into_64(false_reg
);
6758 __reg_combine_32_into_64(true_reg
);
6760 false_reg
->var_off
= false_64off
;
6761 true_reg
->var_off
= true_64off
;
6762 __reg_combine_64_into_32(false_reg
);
6763 __reg_combine_64_into_32(true_reg
);
6767 /* Same as above, but for the case that dst_reg holds a constant and src_reg is
6770 static void reg_set_min_max_inv(struct bpf_reg_state
*true_reg
,
6771 struct bpf_reg_state
*false_reg
,
6773 u8 opcode
, bool is_jmp32
)
6775 /* How can we transform "a <op> b" into "b <op> a"? */
6776 static const u8 opcode_flip
[16] = {
6777 /* these stay the same */
6778 [BPF_JEQ
>> 4] = BPF_JEQ
,
6779 [BPF_JNE
>> 4] = BPF_JNE
,
6780 [BPF_JSET
>> 4] = BPF_JSET
,
6781 /* these swap "lesser" and "greater" (L and G in the opcodes) */
6782 [BPF_JGE
>> 4] = BPF_JLE
,
6783 [BPF_JGT
>> 4] = BPF_JLT
,
6784 [BPF_JLE
>> 4] = BPF_JGE
,
6785 [BPF_JLT
>> 4] = BPF_JGT
,
6786 [BPF_JSGE
>> 4] = BPF_JSLE
,
6787 [BPF_JSGT
>> 4] = BPF_JSLT
,
6788 [BPF_JSLE
>> 4] = BPF_JSGE
,
6789 [BPF_JSLT
>> 4] = BPF_JSGT
6791 opcode
= opcode_flip
[opcode
>> 4];
6792 /* This uses zero as "not present in table"; luckily the zero opcode,
6793 * BPF_JA, can't get here.
6796 reg_set_min_max(true_reg
, false_reg
, val
, val32
, opcode
, is_jmp32
);
6799 /* Regs are known to be equal, so intersect their min/max/var_off */
6800 static void __reg_combine_min_max(struct bpf_reg_state
*src_reg
,
6801 struct bpf_reg_state
*dst_reg
)
6803 src_reg
->umin_value
= dst_reg
->umin_value
= max(src_reg
->umin_value
,
6804 dst_reg
->umin_value
);
6805 src_reg
->umax_value
= dst_reg
->umax_value
= min(src_reg
->umax_value
,
6806 dst_reg
->umax_value
);
6807 src_reg
->smin_value
= dst_reg
->smin_value
= max(src_reg
->smin_value
,
6808 dst_reg
->smin_value
);
6809 src_reg
->smax_value
= dst_reg
->smax_value
= min(src_reg
->smax_value
,
6810 dst_reg
->smax_value
);
6811 src_reg
->var_off
= dst_reg
->var_off
= tnum_intersect(src_reg
->var_off
,
6813 /* We might have learned new bounds from the var_off. */
6814 __update_reg_bounds(src_reg
);
6815 __update_reg_bounds(dst_reg
);
6816 /* We might have learned something about the sign bit. */
6817 __reg_deduce_bounds(src_reg
);
6818 __reg_deduce_bounds(dst_reg
);
6819 /* We might have learned some bits from the bounds. */
6820 __reg_bound_offset(src_reg
);
6821 __reg_bound_offset(dst_reg
);
6822 /* Intersecting with the old var_off might have improved our bounds
6823 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
6824 * then new var_off is (0; 0x7f...fc) which improves our umax.
6826 __update_reg_bounds(src_reg
);
6827 __update_reg_bounds(dst_reg
);
6830 static void reg_combine_min_max(struct bpf_reg_state
*true_src
,
6831 struct bpf_reg_state
*true_dst
,
6832 struct bpf_reg_state
*false_src
,
6833 struct bpf_reg_state
*false_dst
,
6838 __reg_combine_min_max(true_src
, true_dst
);
6841 __reg_combine_min_max(false_src
, false_dst
);
6846 static void mark_ptr_or_null_reg(struct bpf_func_state
*state
,
6847 struct bpf_reg_state
*reg
, u32 id
,
6850 if (reg_type_may_be_null(reg
->type
) && reg
->id
== id
) {
6851 /* Old offset (both fixed and variable parts) should
6852 * have been known-zero, because we don't allow pointer
6853 * arithmetic on pointers that might be NULL.
6855 if (WARN_ON_ONCE(reg
->smin_value
|| reg
->smax_value
||
6856 !tnum_equals_const(reg
->var_off
, 0) ||
6858 __mark_reg_known_zero(reg
);
6862 reg
->type
= SCALAR_VALUE
;
6863 } else if (reg
->type
== PTR_TO_MAP_VALUE_OR_NULL
) {
6864 const struct bpf_map
*map
= reg
->map_ptr
;
6866 if (map
->inner_map_meta
) {
6867 reg
->type
= CONST_PTR_TO_MAP
;
6868 reg
->map_ptr
= map
->inner_map_meta
;
6869 } else if (map
->map_type
== BPF_MAP_TYPE_XSKMAP
) {
6870 reg
->type
= PTR_TO_XDP_SOCK
;
6871 } else if (map
->map_type
== BPF_MAP_TYPE_SOCKMAP
||
6872 map
->map_type
== BPF_MAP_TYPE_SOCKHASH
) {
6873 reg
->type
= PTR_TO_SOCKET
;
6875 reg
->type
= PTR_TO_MAP_VALUE
;
6877 } else if (reg
->type
== PTR_TO_SOCKET_OR_NULL
) {
6878 reg
->type
= PTR_TO_SOCKET
;
6879 } else if (reg
->type
== PTR_TO_SOCK_COMMON_OR_NULL
) {
6880 reg
->type
= PTR_TO_SOCK_COMMON
;
6881 } else if (reg
->type
== PTR_TO_TCP_SOCK_OR_NULL
) {
6882 reg
->type
= PTR_TO_TCP_SOCK
;
6883 } else if (reg
->type
== PTR_TO_BTF_ID_OR_NULL
) {
6884 reg
->type
= PTR_TO_BTF_ID
;
6885 } else if (reg
->type
== PTR_TO_MEM_OR_NULL
) {
6886 reg
->type
= PTR_TO_MEM
;
6887 } else if (reg
->type
== PTR_TO_RDONLY_BUF_OR_NULL
) {
6888 reg
->type
= PTR_TO_RDONLY_BUF
;
6889 } else if (reg
->type
== PTR_TO_RDWR_BUF_OR_NULL
) {
6890 reg
->type
= PTR_TO_RDWR_BUF
;
6893 /* We don't need id and ref_obj_id from this point
6894 * onwards anymore, thus we should better reset it,
6895 * so that state pruning has chances to take effect.
6898 reg
->ref_obj_id
= 0;
6899 } else if (!reg_may_point_to_spin_lock(reg
)) {
6900 /* For not-NULL ptr, reg->ref_obj_id will be reset
6901 * in release_reg_references().
6903 * reg->id is still used by spin_lock ptr. Other
6904 * than spin_lock ptr type, reg->id can be reset.
6911 static void __mark_ptr_or_null_regs(struct bpf_func_state
*state
, u32 id
,
6914 struct bpf_reg_state
*reg
;
6917 for (i
= 0; i
< MAX_BPF_REG
; i
++)
6918 mark_ptr_or_null_reg(state
, &state
->regs
[i
], id
, is_null
);
6920 bpf_for_each_spilled_reg(i
, state
, reg
) {
6923 mark_ptr_or_null_reg(state
, reg
, id
, is_null
);
6927 /* The logic is similar to find_good_pkt_pointers(), both could eventually
6928 * be folded together at some point.
6930 static void mark_ptr_or_null_regs(struct bpf_verifier_state
*vstate
, u32 regno
,
6933 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
6934 struct bpf_reg_state
*regs
= state
->regs
;
6935 u32 ref_obj_id
= regs
[regno
].ref_obj_id
;
6936 u32 id
= regs
[regno
].id
;
6939 if (ref_obj_id
&& ref_obj_id
== id
&& is_null
)
6940 /* regs[regno] is in the " == NULL" branch.
6941 * No one could have freed the reference state before
6942 * doing the NULL check.
6944 WARN_ON_ONCE(release_reference_state(state
, id
));
6946 for (i
= 0; i
<= vstate
->curframe
; i
++)
6947 __mark_ptr_or_null_regs(vstate
->frame
[i
], id
, is_null
);
6950 static bool try_match_pkt_pointers(const struct bpf_insn
*insn
,
6951 struct bpf_reg_state
*dst_reg
,
6952 struct bpf_reg_state
*src_reg
,
6953 struct bpf_verifier_state
*this_branch
,
6954 struct bpf_verifier_state
*other_branch
)
6956 if (BPF_SRC(insn
->code
) != BPF_X
)
6959 /* Pointers are always 64-bit. */
6960 if (BPF_CLASS(insn
->code
) == BPF_JMP32
)
6963 switch (BPF_OP(insn
->code
)) {
6965 if ((dst_reg
->type
== PTR_TO_PACKET
&&
6966 src_reg
->type
== PTR_TO_PACKET_END
) ||
6967 (dst_reg
->type
== PTR_TO_PACKET_META
&&
6968 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
6969 /* pkt_data' > pkt_end, pkt_meta' > pkt_data */
6970 find_good_pkt_pointers(this_branch
, dst_reg
,
6971 dst_reg
->type
, false);
6972 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
6973 src_reg
->type
== PTR_TO_PACKET
) ||
6974 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
6975 src_reg
->type
== PTR_TO_PACKET_META
)) {
6976 /* pkt_end > pkt_data', pkt_data > pkt_meta' */
6977 find_good_pkt_pointers(other_branch
, src_reg
,
6978 src_reg
->type
, true);
6984 if ((dst_reg
->type
== PTR_TO_PACKET
&&
6985 src_reg
->type
== PTR_TO_PACKET_END
) ||
6986 (dst_reg
->type
== PTR_TO_PACKET_META
&&
6987 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
6988 /* pkt_data' < pkt_end, pkt_meta' < pkt_data */
6989 find_good_pkt_pointers(other_branch
, dst_reg
,
6990 dst_reg
->type
, true);
6991 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
6992 src_reg
->type
== PTR_TO_PACKET
) ||
6993 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
6994 src_reg
->type
== PTR_TO_PACKET_META
)) {
6995 /* pkt_end < pkt_data', pkt_data > pkt_meta' */
6996 find_good_pkt_pointers(this_branch
, src_reg
,
6997 src_reg
->type
, false);
7003 if ((dst_reg
->type
== PTR_TO_PACKET
&&
7004 src_reg
->type
== PTR_TO_PACKET_END
) ||
7005 (dst_reg
->type
== PTR_TO_PACKET_META
&&
7006 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
7007 /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
7008 find_good_pkt_pointers(this_branch
, dst_reg
,
7009 dst_reg
->type
, true);
7010 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
7011 src_reg
->type
== PTR_TO_PACKET
) ||
7012 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
7013 src_reg
->type
== PTR_TO_PACKET_META
)) {
7014 /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
7015 find_good_pkt_pointers(other_branch
, src_reg
,
7016 src_reg
->type
, false);
7022 if ((dst_reg
->type
== PTR_TO_PACKET
&&
7023 src_reg
->type
== PTR_TO_PACKET_END
) ||
7024 (dst_reg
->type
== PTR_TO_PACKET_META
&&
7025 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
7026 /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
7027 find_good_pkt_pointers(other_branch
, dst_reg
,
7028 dst_reg
->type
, false);
7029 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
7030 src_reg
->type
== PTR_TO_PACKET
) ||
7031 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
7032 src_reg
->type
== PTR_TO_PACKET_META
)) {
7033 /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
7034 find_good_pkt_pointers(this_branch
, src_reg
,
7035 src_reg
->type
, true);
7047 static int check_cond_jmp_op(struct bpf_verifier_env
*env
,
7048 struct bpf_insn
*insn
, int *insn_idx
)
7050 struct bpf_verifier_state
*this_branch
= env
->cur_state
;
7051 struct bpf_verifier_state
*other_branch
;
7052 struct bpf_reg_state
*regs
= this_branch
->frame
[this_branch
->curframe
]->regs
;
7053 struct bpf_reg_state
*dst_reg
, *other_branch_regs
, *src_reg
= NULL
;
7054 u8 opcode
= BPF_OP(insn
->code
);
7059 /* Only conditional jumps are expected to reach here. */
7060 if (opcode
== BPF_JA
|| opcode
> BPF_JSLE
) {
7061 verbose(env
, "invalid BPF_JMP/JMP32 opcode %x\n", opcode
);
7065 if (BPF_SRC(insn
->code
) == BPF_X
) {
7066 if (insn
->imm
!= 0) {
7067 verbose(env
, "BPF_JMP/JMP32 uses reserved fields\n");
7071 /* check src1 operand */
7072 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
7076 if (is_pointer_value(env
, insn
->src_reg
)) {
7077 verbose(env
, "R%d pointer comparison prohibited\n",
7081 src_reg
= ®s
[insn
->src_reg
];
7083 if (insn
->src_reg
!= BPF_REG_0
) {
7084 verbose(env
, "BPF_JMP/JMP32 uses reserved fields\n");
7089 /* check src2 operand */
7090 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
7094 dst_reg
= ®s
[insn
->dst_reg
];
7095 is_jmp32
= BPF_CLASS(insn
->code
) == BPF_JMP32
;
7097 if (BPF_SRC(insn
->code
) == BPF_K
) {
7098 pred
= is_branch_taken(dst_reg
, insn
->imm
, opcode
, is_jmp32
);
7099 } else if (src_reg
->type
== SCALAR_VALUE
&&
7100 is_jmp32
&& tnum_is_const(tnum_subreg(src_reg
->var_off
))) {
7101 pred
= is_branch_taken(dst_reg
,
7102 tnum_subreg(src_reg
->var_off
).value
,
7105 } else if (src_reg
->type
== SCALAR_VALUE
&&
7106 !is_jmp32
&& tnum_is_const(src_reg
->var_off
)) {
7107 pred
= is_branch_taken(dst_reg
,
7108 src_reg
->var_off
.value
,
7114 /* If we get here with a dst_reg pointer type it is because
7115 * above is_branch_taken() special cased the 0 comparison.
7117 if (!__is_pointer_value(false, dst_reg
))
7118 err
= mark_chain_precision(env
, insn
->dst_reg
);
7119 if (BPF_SRC(insn
->code
) == BPF_X
&& !err
)
7120 err
= mark_chain_precision(env
, insn
->src_reg
);
7125 /* only follow the goto, ignore fall-through */
7126 *insn_idx
+= insn
->off
;
7128 } else if (pred
== 0) {
7129 /* only follow fall-through branch, since
7130 * that's where the program will go
7135 other_branch
= push_stack(env
, *insn_idx
+ insn
->off
+ 1, *insn_idx
,
7139 other_branch_regs
= other_branch
->frame
[other_branch
->curframe
]->regs
;
7141 /* detect if we are comparing against a constant value so we can adjust
7142 * our min/max values for our dst register.
7143 * this is only legit if both are scalars (or pointers to the same
7144 * object, I suppose, but we don't support that right now), because
7145 * otherwise the different base pointers mean the offsets aren't
7148 if (BPF_SRC(insn
->code
) == BPF_X
) {
7149 struct bpf_reg_state
*src_reg
= ®s
[insn
->src_reg
];
7151 if (dst_reg
->type
== SCALAR_VALUE
&&
7152 src_reg
->type
== SCALAR_VALUE
) {
7153 if (tnum_is_const(src_reg
->var_off
) ||
7155 tnum_is_const(tnum_subreg(src_reg
->var_off
))))
7156 reg_set_min_max(&other_branch_regs
[insn
->dst_reg
],
7158 src_reg
->var_off
.value
,
7159 tnum_subreg(src_reg
->var_off
).value
,
7161 else if (tnum_is_const(dst_reg
->var_off
) ||
7163 tnum_is_const(tnum_subreg(dst_reg
->var_off
))))
7164 reg_set_min_max_inv(&other_branch_regs
[insn
->src_reg
],
7166 dst_reg
->var_off
.value
,
7167 tnum_subreg(dst_reg
->var_off
).value
,
7169 else if (!is_jmp32
&&
7170 (opcode
== BPF_JEQ
|| opcode
== BPF_JNE
))
7171 /* Comparing for equality, we can combine knowledge */
7172 reg_combine_min_max(&other_branch_regs
[insn
->src_reg
],
7173 &other_branch_regs
[insn
->dst_reg
],
7174 src_reg
, dst_reg
, opcode
);
7176 } else if (dst_reg
->type
== SCALAR_VALUE
) {
7177 reg_set_min_max(&other_branch_regs
[insn
->dst_reg
],
7178 dst_reg
, insn
->imm
, (u32
)insn
->imm
,
7182 /* detect if R == 0 where R is returned from bpf_map_lookup_elem().
7183 * NOTE: these optimizations below are related with pointer comparison
7184 * which will never be JMP32.
7186 if (!is_jmp32
&& BPF_SRC(insn
->code
) == BPF_K
&&
7187 insn
->imm
== 0 && (opcode
== BPF_JEQ
|| opcode
== BPF_JNE
) &&
7188 reg_type_may_be_null(dst_reg
->type
)) {
7189 /* Mark all identical registers in each branch as either
7190 * safe or unknown depending R == 0 or R != 0 conditional.
7192 mark_ptr_or_null_regs(this_branch
, insn
->dst_reg
,
7194 mark_ptr_or_null_regs(other_branch
, insn
->dst_reg
,
7196 } else if (!try_match_pkt_pointers(insn
, dst_reg
, ®s
[insn
->src_reg
],
7197 this_branch
, other_branch
) &&
7198 is_pointer_value(env
, insn
->dst_reg
)) {
7199 verbose(env
, "R%d pointer comparison prohibited\n",
7203 if (env
->log
.level
& BPF_LOG_LEVEL
)
7204 print_verifier_state(env
, this_branch
->frame
[this_branch
->curframe
]);
7208 /* verify BPF_LD_IMM64 instruction */
7209 static int check_ld_imm(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
7211 struct bpf_insn_aux_data
*aux
= cur_aux(env
);
7212 struct bpf_reg_state
*regs
= cur_regs(env
);
7213 struct bpf_map
*map
;
7216 if (BPF_SIZE(insn
->code
) != BPF_DW
) {
7217 verbose(env
, "invalid BPF_LD_IMM insn\n");
7220 if (insn
->off
!= 0) {
7221 verbose(env
, "BPF_LD_IMM64 uses reserved fields\n");
7225 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP
);
7229 if (insn
->src_reg
== 0) {
7230 u64 imm
= ((u64
)(insn
+ 1)->imm
<< 32) | (u32
)insn
->imm
;
7232 regs
[insn
->dst_reg
].type
= SCALAR_VALUE
;
7233 __mark_reg_known(®s
[insn
->dst_reg
], imm
);
7237 map
= env
->used_maps
[aux
->map_index
];
7238 mark_reg_known_zero(env
, regs
, insn
->dst_reg
);
7239 regs
[insn
->dst_reg
].map_ptr
= map
;
7241 if (insn
->src_reg
== BPF_PSEUDO_MAP_VALUE
) {
7242 regs
[insn
->dst_reg
].type
= PTR_TO_MAP_VALUE
;
7243 regs
[insn
->dst_reg
].off
= aux
->map_off
;
7244 if (map_value_has_spin_lock(map
))
7245 regs
[insn
->dst_reg
].id
= ++env
->id_gen
;
7246 } else if (insn
->src_reg
== BPF_PSEUDO_MAP_FD
) {
7247 regs
[insn
->dst_reg
].type
= CONST_PTR_TO_MAP
;
7249 verbose(env
, "bpf verifier is misconfigured\n");
7256 static bool may_access_skb(enum bpf_prog_type type
)
7259 case BPF_PROG_TYPE_SOCKET_FILTER
:
7260 case BPF_PROG_TYPE_SCHED_CLS
:
7261 case BPF_PROG_TYPE_SCHED_ACT
:
7268 /* verify safety of LD_ABS|LD_IND instructions:
7269 * - they can only appear in the programs where ctx == skb
7270 * - since they are wrappers of function calls, they scratch R1-R5 registers,
7271 * preserve R6-R9, and store return value into R0
7274 * ctx == skb == R6 == CTX
7277 * SRC == any register
7278 * IMM == 32-bit immediate
7281 * R0 - 8/16/32-bit skb data converted to cpu endianness
7283 static int check_ld_abs(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
7285 struct bpf_reg_state
*regs
= cur_regs(env
);
7286 static const int ctx_reg
= BPF_REG_6
;
7287 u8 mode
= BPF_MODE(insn
->code
);
7290 if (!may_access_skb(env
->prog
->type
)) {
7291 verbose(env
, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
7295 if (!env
->ops
->gen_ld_abs
) {
7296 verbose(env
, "bpf verifier is misconfigured\n");
7300 if (env
->subprog_cnt
> 1) {
7301 /* when program has LD_ABS insn JITs and interpreter assume
7302 * that r1 == ctx == skb which is not the case for callees
7303 * that can have arbitrary arguments. It's problematic
7304 * for main prog as well since JITs would need to analyze
7305 * all functions in order to make proper register save/restore
7306 * decisions in the main prog. Hence disallow LD_ABS with calls
7308 verbose(env
, "BPF_LD_[ABS|IND] instructions cannot be mixed with bpf-to-bpf calls\n");
7312 if (insn
->dst_reg
!= BPF_REG_0
|| insn
->off
!= 0 ||
7313 BPF_SIZE(insn
->code
) == BPF_DW
||
7314 (mode
== BPF_ABS
&& insn
->src_reg
!= BPF_REG_0
)) {
7315 verbose(env
, "BPF_LD_[ABS|IND] uses reserved fields\n");
7319 /* check whether implicit source operand (register R6) is readable */
7320 err
= check_reg_arg(env
, ctx_reg
, SRC_OP
);
7324 /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
7325 * gen_ld_abs() may terminate the program at runtime, leading to
7328 err
= check_reference_leak(env
);
7330 verbose(env
, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
7334 if (env
->cur_state
->active_spin_lock
) {
7335 verbose(env
, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
7339 if (regs
[ctx_reg
].type
!= PTR_TO_CTX
) {
7341 "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
7345 if (mode
== BPF_IND
) {
7346 /* check explicit source operand */
7347 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
7352 err
= check_ctx_reg(env
, ®s
[ctx_reg
], ctx_reg
);
7356 /* reset caller saved regs to unreadable */
7357 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
7358 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
7359 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
7362 /* mark destination R0 register as readable, since it contains
7363 * the value fetched from the packet.
7364 * Already marked as written above.
7366 mark_reg_unknown(env
, regs
, BPF_REG_0
);
7367 /* ld_abs load up to 32-bit skb data. */
7368 regs
[BPF_REG_0
].subreg_def
= env
->insn_idx
+ 1;
7372 static int check_return_code(struct bpf_verifier_env
*env
)
7374 struct tnum enforce_attach_type_range
= tnum_unknown
;
7375 const struct bpf_prog
*prog
= env
->prog
;
7376 struct bpf_reg_state
*reg
;
7377 struct tnum range
= tnum_range(0, 1);
7380 /* LSM and struct_ops func-ptr's return type could be "void" */
7381 if ((env
->prog
->type
== BPF_PROG_TYPE_STRUCT_OPS
||
7382 env
->prog
->type
== BPF_PROG_TYPE_LSM
) &&
7383 !prog
->aux
->attach_func_proto
->type
)
7386 /* eBPF calling convetion is such that R0 is used
7387 * to return the value from eBPF program.
7388 * Make sure that it's readable at this time
7389 * of bpf_exit, which means that program wrote
7390 * something into it earlier
7392 err
= check_reg_arg(env
, BPF_REG_0
, SRC_OP
);
7396 if (is_pointer_value(env
, BPF_REG_0
)) {
7397 verbose(env
, "R0 leaks addr as return value\n");
7401 switch (env
->prog
->type
) {
7402 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR
:
7403 if (env
->prog
->expected_attach_type
== BPF_CGROUP_UDP4_RECVMSG
||
7404 env
->prog
->expected_attach_type
== BPF_CGROUP_UDP6_RECVMSG
||
7405 env
->prog
->expected_attach_type
== BPF_CGROUP_INET4_GETPEERNAME
||
7406 env
->prog
->expected_attach_type
== BPF_CGROUP_INET6_GETPEERNAME
||
7407 env
->prog
->expected_attach_type
== BPF_CGROUP_INET4_GETSOCKNAME
||
7408 env
->prog
->expected_attach_type
== BPF_CGROUP_INET6_GETSOCKNAME
)
7409 range
= tnum_range(1, 1);
7411 case BPF_PROG_TYPE_CGROUP_SKB
:
7412 if (env
->prog
->expected_attach_type
== BPF_CGROUP_INET_EGRESS
) {
7413 range
= tnum_range(0, 3);
7414 enforce_attach_type_range
= tnum_range(2, 3);
7417 case BPF_PROG_TYPE_CGROUP_SOCK
:
7418 case BPF_PROG_TYPE_SOCK_OPS
:
7419 case BPF_PROG_TYPE_CGROUP_DEVICE
:
7420 case BPF_PROG_TYPE_CGROUP_SYSCTL
:
7421 case BPF_PROG_TYPE_CGROUP_SOCKOPT
:
7423 case BPF_PROG_TYPE_RAW_TRACEPOINT
:
7424 if (!env
->prog
->aux
->attach_btf_id
)
7426 range
= tnum_const(0);
7428 case BPF_PROG_TYPE_TRACING
:
7429 switch (env
->prog
->expected_attach_type
) {
7430 case BPF_TRACE_FENTRY
:
7431 case BPF_TRACE_FEXIT
:
7432 range
= tnum_const(0);
7434 case BPF_TRACE_RAW_TP
:
7435 case BPF_MODIFY_RETURN
:
7437 case BPF_TRACE_ITER
:
7443 case BPF_PROG_TYPE_SK_LOOKUP
:
7444 range
= tnum_range(SK_DROP
, SK_PASS
);
7446 case BPF_PROG_TYPE_EXT
:
7447 /* freplace program can return anything as its return value
7448 * depends on the to-be-replaced kernel func or bpf program.
7454 reg
= cur_regs(env
) + BPF_REG_0
;
7455 if (reg
->type
!= SCALAR_VALUE
) {
7456 verbose(env
, "At program exit the register R0 is not a known value (%s)\n",
7457 reg_type_str
[reg
->type
]);
7461 if (!tnum_in(range
, reg
->var_off
)) {
7464 verbose(env
, "At program exit the register R0 ");
7465 if (!tnum_is_unknown(reg
->var_off
)) {
7466 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
7467 verbose(env
, "has value %s", tn_buf
);
7469 verbose(env
, "has unknown scalar value");
7471 tnum_strn(tn_buf
, sizeof(tn_buf
), range
);
7472 verbose(env
, " should have been in %s\n", tn_buf
);
7476 if (!tnum_is_unknown(enforce_attach_type_range
) &&
7477 tnum_in(enforce_attach_type_range
, reg
->var_off
))
7478 env
->prog
->enforce_expected_attach_type
= 1;
7482 /* non-recursive DFS pseudo code
7483 * 1 procedure DFS-iterative(G,v):
7484 * 2 label v as discovered
7485 * 3 let S be a stack
7487 * 5 while S is not empty
7489 * 7 if t is what we're looking for:
7491 * 9 for all edges e in G.adjacentEdges(t) do
7492 * 10 if edge e is already labelled
7493 * 11 continue with the next edge
7494 * 12 w <- G.adjacentVertex(t,e)
7495 * 13 if vertex w is not discovered and not explored
7496 * 14 label e as tree-edge
7497 * 15 label w as discovered
7500 * 18 else if vertex w is discovered
7501 * 19 label e as back-edge
7503 * 21 // vertex w is explored
7504 * 22 label e as forward- or cross-edge
7505 * 23 label t as explored
7510 * 0x11 - discovered and fall-through edge labelled
7511 * 0x12 - discovered and fall-through and branch edges labelled
7522 static u32
state_htab_size(struct bpf_verifier_env
*env
)
7524 return env
->prog
->len
;
7527 static struct bpf_verifier_state_list
**explored_state(
7528 struct bpf_verifier_env
*env
,
7531 struct bpf_verifier_state
*cur
= env
->cur_state
;
7532 struct bpf_func_state
*state
= cur
->frame
[cur
->curframe
];
7534 return &env
->explored_states
[(idx
^ state
->callsite
) % state_htab_size(env
)];
7537 static void init_explored_state(struct bpf_verifier_env
*env
, int idx
)
7539 env
->insn_aux_data
[idx
].prune_point
= true;
7542 /* t, w, e - match pseudo-code above:
7543 * t - index of current instruction
7544 * w - next instruction
7547 static int push_insn(int t
, int w
, int e
, struct bpf_verifier_env
*env
,
7550 int *insn_stack
= env
->cfg
.insn_stack
;
7551 int *insn_state
= env
->cfg
.insn_state
;
7553 if (e
== FALLTHROUGH
&& insn_state
[t
] >= (DISCOVERED
| FALLTHROUGH
))
7556 if (e
== BRANCH
&& insn_state
[t
] >= (DISCOVERED
| BRANCH
))
7559 if (w
< 0 || w
>= env
->prog
->len
) {
7560 verbose_linfo(env
, t
, "%d: ", t
);
7561 verbose(env
, "jump out of range from insn %d to %d\n", t
, w
);
7566 /* mark branch target for state pruning */
7567 init_explored_state(env
, w
);
7569 if (insn_state
[w
] == 0) {
7571 insn_state
[t
] = DISCOVERED
| e
;
7572 insn_state
[w
] = DISCOVERED
;
7573 if (env
->cfg
.cur_stack
>= env
->prog
->len
)
7575 insn_stack
[env
->cfg
.cur_stack
++] = w
;
7577 } else if ((insn_state
[w
] & 0xF0) == DISCOVERED
) {
7578 if (loop_ok
&& env
->bpf_capable
)
7580 verbose_linfo(env
, t
, "%d: ", t
);
7581 verbose_linfo(env
, w
, "%d: ", w
);
7582 verbose(env
, "back-edge from insn %d to %d\n", t
, w
);
7584 } else if (insn_state
[w
] == EXPLORED
) {
7585 /* forward- or cross-edge */
7586 insn_state
[t
] = DISCOVERED
| e
;
7588 verbose(env
, "insn state internal bug\n");
7594 /* non-recursive depth-first-search to detect loops in BPF program
7595 * loop == back-edge in directed graph
7597 static int check_cfg(struct bpf_verifier_env
*env
)
7599 struct bpf_insn
*insns
= env
->prog
->insnsi
;
7600 int insn_cnt
= env
->prog
->len
;
7601 int *insn_stack
, *insn_state
;
7605 insn_state
= env
->cfg
.insn_state
= kvcalloc(insn_cnt
, sizeof(int), GFP_KERNEL
);
7609 insn_stack
= env
->cfg
.insn_stack
= kvcalloc(insn_cnt
, sizeof(int), GFP_KERNEL
);
7615 insn_state
[0] = DISCOVERED
; /* mark 1st insn as discovered */
7616 insn_stack
[0] = 0; /* 0 is the first instruction */
7617 env
->cfg
.cur_stack
= 1;
7620 if (env
->cfg
.cur_stack
== 0)
7622 t
= insn_stack
[env
->cfg
.cur_stack
- 1];
7624 if (BPF_CLASS(insns
[t
].code
) == BPF_JMP
||
7625 BPF_CLASS(insns
[t
].code
) == BPF_JMP32
) {
7626 u8 opcode
= BPF_OP(insns
[t
].code
);
7628 if (opcode
== BPF_EXIT
) {
7630 } else if (opcode
== BPF_CALL
) {
7631 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
, false);
7636 if (t
+ 1 < insn_cnt
)
7637 init_explored_state(env
, t
+ 1);
7638 if (insns
[t
].src_reg
== BPF_PSEUDO_CALL
) {
7639 init_explored_state(env
, t
);
7640 ret
= push_insn(t
, t
+ insns
[t
].imm
+ 1, BRANCH
,
7647 } else if (opcode
== BPF_JA
) {
7648 if (BPF_SRC(insns
[t
].code
) != BPF_K
) {
7652 /* unconditional jump with single edge */
7653 ret
= push_insn(t
, t
+ insns
[t
].off
+ 1,
7654 FALLTHROUGH
, env
, true);
7659 /* unconditional jmp is not a good pruning point,
7660 * but it's marked, since backtracking needs
7661 * to record jmp history in is_state_visited().
7663 init_explored_state(env
, t
+ insns
[t
].off
+ 1);
7664 /* tell verifier to check for equivalent states
7665 * after every call and jump
7667 if (t
+ 1 < insn_cnt
)
7668 init_explored_state(env
, t
+ 1);
7670 /* conditional jump with two edges */
7671 init_explored_state(env
, t
);
7672 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
, true);
7678 ret
= push_insn(t
, t
+ insns
[t
].off
+ 1, BRANCH
, env
, true);
7685 /* all other non-branch instructions with single
7688 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
, false);
7696 insn_state
[t
] = EXPLORED
;
7697 if (env
->cfg
.cur_stack
-- <= 0) {
7698 verbose(env
, "pop stack internal bug\n");
7705 for (i
= 0; i
< insn_cnt
; i
++) {
7706 if (insn_state
[i
] != EXPLORED
) {
7707 verbose(env
, "unreachable insn %d\n", i
);
7712 ret
= 0; /* cfg looks good */
7717 env
->cfg
.insn_state
= env
->cfg
.insn_stack
= NULL
;
7721 /* The minimum supported BTF func info size */
7722 #define MIN_BPF_FUNCINFO_SIZE 8
7723 #define MAX_FUNCINFO_REC_SIZE 252
7725 static int check_btf_func(struct bpf_verifier_env
*env
,
7726 const union bpf_attr
*attr
,
7727 union bpf_attr __user
*uattr
)
7729 u32 i
, nfuncs
, urec_size
, min_size
;
7730 u32 krec_size
= sizeof(struct bpf_func_info
);
7731 struct bpf_func_info
*krecord
;
7732 struct bpf_func_info_aux
*info_aux
= NULL
;
7733 const struct btf_type
*type
;
7734 struct bpf_prog
*prog
;
7735 const struct btf
*btf
;
7736 void __user
*urecord
;
7737 u32 prev_offset
= 0;
7740 nfuncs
= attr
->func_info_cnt
;
7744 if (nfuncs
!= env
->subprog_cnt
) {
7745 verbose(env
, "number of funcs in func_info doesn't match number of subprogs\n");
7749 urec_size
= attr
->func_info_rec_size
;
7750 if (urec_size
< MIN_BPF_FUNCINFO_SIZE
||
7751 urec_size
> MAX_FUNCINFO_REC_SIZE
||
7752 urec_size
% sizeof(u32
)) {
7753 verbose(env
, "invalid func info rec size %u\n", urec_size
);
7758 btf
= prog
->aux
->btf
;
7760 urecord
= u64_to_user_ptr(attr
->func_info
);
7761 min_size
= min_t(u32
, krec_size
, urec_size
);
7763 krecord
= kvcalloc(nfuncs
, krec_size
, GFP_KERNEL
| __GFP_NOWARN
);
7766 info_aux
= kcalloc(nfuncs
, sizeof(*info_aux
), GFP_KERNEL
| __GFP_NOWARN
);
7770 for (i
= 0; i
< nfuncs
; i
++) {
7771 ret
= bpf_check_uarg_tail_zero(urecord
, krec_size
, urec_size
);
7773 if (ret
== -E2BIG
) {
7774 verbose(env
, "nonzero tailing record in func info");
7775 /* set the size kernel expects so loader can zero
7776 * out the rest of the record.
7778 if (put_user(min_size
, &uattr
->func_info_rec_size
))
7784 if (copy_from_user(&krecord
[i
], urecord
, min_size
)) {
7789 /* check insn_off */
7791 if (krecord
[i
].insn_off
) {
7793 "nonzero insn_off %u for the first func info record",
7794 krecord
[i
].insn_off
);
7798 } else if (krecord
[i
].insn_off
<= prev_offset
) {
7800 "same or smaller insn offset (%u) than previous func info record (%u)",
7801 krecord
[i
].insn_off
, prev_offset
);
7806 if (env
->subprog_info
[i
].start
!= krecord
[i
].insn_off
) {
7807 verbose(env
, "func_info BTF section doesn't match subprog layout in BPF program\n");
7813 type
= btf_type_by_id(btf
, krecord
[i
].type_id
);
7814 if (!type
|| !btf_type_is_func(type
)) {
7815 verbose(env
, "invalid type id %d in func info",
7816 krecord
[i
].type_id
);
7820 info_aux
[i
].linkage
= BTF_INFO_VLEN(type
->info
);
7821 prev_offset
= krecord
[i
].insn_off
;
7822 urecord
+= urec_size
;
7825 prog
->aux
->func_info
= krecord
;
7826 prog
->aux
->func_info_cnt
= nfuncs
;
7827 prog
->aux
->func_info_aux
= info_aux
;
7836 static void adjust_btf_func(struct bpf_verifier_env
*env
)
7838 struct bpf_prog_aux
*aux
= env
->prog
->aux
;
7841 if (!aux
->func_info
)
7844 for (i
= 0; i
< env
->subprog_cnt
; i
++)
7845 aux
->func_info
[i
].insn_off
= env
->subprog_info
[i
].start
;
7848 #define MIN_BPF_LINEINFO_SIZE (offsetof(struct bpf_line_info, line_col) + \
7849 sizeof(((struct bpf_line_info *)(0))->line_col))
7850 #define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE
7852 static int check_btf_line(struct bpf_verifier_env
*env
,
7853 const union bpf_attr
*attr
,
7854 union bpf_attr __user
*uattr
)
7856 u32 i
, s
, nr_linfo
, ncopy
, expected_size
, rec_size
, prev_offset
= 0;
7857 struct bpf_subprog_info
*sub
;
7858 struct bpf_line_info
*linfo
;
7859 struct bpf_prog
*prog
;
7860 const struct btf
*btf
;
7861 void __user
*ulinfo
;
7864 nr_linfo
= attr
->line_info_cnt
;
7868 rec_size
= attr
->line_info_rec_size
;
7869 if (rec_size
< MIN_BPF_LINEINFO_SIZE
||
7870 rec_size
> MAX_LINEINFO_REC_SIZE
||
7871 rec_size
& (sizeof(u32
) - 1))
7874 /* Need to zero it in case the userspace may
7875 * pass in a smaller bpf_line_info object.
7877 linfo
= kvcalloc(nr_linfo
, sizeof(struct bpf_line_info
),
7878 GFP_KERNEL
| __GFP_NOWARN
);
7883 btf
= prog
->aux
->btf
;
7886 sub
= env
->subprog_info
;
7887 ulinfo
= u64_to_user_ptr(attr
->line_info
);
7888 expected_size
= sizeof(struct bpf_line_info
);
7889 ncopy
= min_t(u32
, expected_size
, rec_size
);
7890 for (i
= 0; i
< nr_linfo
; i
++) {
7891 err
= bpf_check_uarg_tail_zero(ulinfo
, expected_size
, rec_size
);
7893 if (err
== -E2BIG
) {
7894 verbose(env
, "nonzero tailing record in line_info");
7895 if (put_user(expected_size
,
7896 &uattr
->line_info_rec_size
))
7902 if (copy_from_user(&linfo
[i
], ulinfo
, ncopy
)) {
7908 * Check insn_off to ensure
7909 * 1) strictly increasing AND
7910 * 2) bounded by prog->len
7912 * The linfo[0].insn_off == 0 check logically falls into
7913 * the later "missing bpf_line_info for func..." case
7914 * because the first linfo[0].insn_off must be the
7915 * first sub also and the first sub must have
7916 * subprog_info[0].start == 0.
7918 if ((i
&& linfo
[i
].insn_off
<= prev_offset
) ||
7919 linfo
[i
].insn_off
>= prog
->len
) {
7920 verbose(env
, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
7921 i
, linfo
[i
].insn_off
, prev_offset
,
7927 if (!prog
->insnsi
[linfo
[i
].insn_off
].code
) {
7929 "Invalid insn code at line_info[%u].insn_off\n",
7935 if (!btf_name_by_offset(btf
, linfo
[i
].line_off
) ||
7936 !btf_name_by_offset(btf
, linfo
[i
].file_name_off
)) {
7937 verbose(env
, "Invalid line_info[%u].line_off or .file_name_off\n", i
);
7942 if (s
!= env
->subprog_cnt
) {
7943 if (linfo
[i
].insn_off
== sub
[s
].start
) {
7944 sub
[s
].linfo_idx
= i
;
7946 } else if (sub
[s
].start
< linfo
[i
].insn_off
) {
7947 verbose(env
, "missing bpf_line_info for func#%u\n", s
);
7953 prev_offset
= linfo
[i
].insn_off
;
7957 if (s
!= env
->subprog_cnt
) {
7958 verbose(env
, "missing bpf_line_info for %u funcs starting from func#%u\n",
7959 env
->subprog_cnt
- s
, s
);
7964 prog
->aux
->linfo
= linfo
;
7965 prog
->aux
->nr_linfo
= nr_linfo
;
7974 static int check_btf_info(struct bpf_verifier_env
*env
,
7975 const union bpf_attr
*attr
,
7976 union bpf_attr __user
*uattr
)
7981 if (!attr
->func_info_cnt
&& !attr
->line_info_cnt
)
7984 btf
= btf_get_by_fd(attr
->prog_btf_fd
);
7986 return PTR_ERR(btf
);
7987 env
->prog
->aux
->btf
= btf
;
7989 err
= check_btf_func(env
, attr
, uattr
);
7993 err
= check_btf_line(env
, attr
, uattr
);
8000 /* check %cur's range satisfies %old's */
8001 static bool range_within(struct bpf_reg_state
*old
,
8002 struct bpf_reg_state
*cur
)
8004 return old
->umin_value
<= cur
->umin_value
&&
8005 old
->umax_value
>= cur
->umax_value
&&
8006 old
->smin_value
<= cur
->smin_value
&&
8007 old
->smax_value
>= cur
->smax_value
;
8010 /* Maximum number of register states that can exist at once */
8011 #define ID_MAP_SIZE (MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE)
8017 /* If in the old state two registers had the same id, then they need to have
8018 * the same id in the new state as well. But that id could be different from
8019 * the old state, so we need to track the mapping from old to new ids.
8020 * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent
8021 * regs with old id 5 must also have new id 9 for the new state to be safe. But
8022 * regs with a different old id could still have new id 9, we don't care about
8024 * So we look through our idmap to see if this old id has been seen before. If
8025 * so, we require the new id to match; otherwise, we add the id pair to the map.
8027 static bool check_ids(u32 old_id
, u32 cur_id
, struct idpair
*idmap
)
8031 for (i
= 0; i
< ID_MAP_SIZE
; i
++) {
8032 if (!idmap
[i
].old
) {
8033 /* Reached an empty slot; haven't seen this id before */
8034 idmap
[i
].old
= old_id
;
8035 idmap
[i
].cur
= cur_id
;
8038 if (idmap
[i
].old
== old_id
)
8039 return idmap
[i
].cur
== cur_id
;
8041 /* We ran out of idmap slots, which should be impossible */
8046 static void clean_func_state(struct bpf_verifier_env
*env
,
8047 struct bpf_func_state
*st
)
8049 enum bpf_reg_liveness live
;
8052 for (i
= 0; i
< BPF_REG_FP
; i
++) {
8053 live
= st
->regs
[i
].live
;
8054 /* liveness must not touch this register anymore */
8055 st
->regs
[i
].live
|= REG_LIVE_DONE
;
8056 if (!(live
& REG_LIVE_READ
))
8057 /* since the register is unused, clear its state
8058 * to make further comparison simpler
8060 __mark_reg_not_init(env
, &st
->regs
[i
]);
8063 for (i
= 0; i
< st
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
8064 live
= st
->stack
[i
].spilled_ptr
.live
;
8065 /* liveness must not touch this stack slot anymore */
8066 st
->stack
[i
].spilled_ptr
.live
|= REG_LIVE_DONE
;
8067 if (!(live
& REG_LIVE_READ
)) {
8068 __mark_reg_not_init(env
, &st
->stack
[i
].spilled_ptr
);
8069 for (j
= 0; j
< BPF_REG_SIZE
; j
++)
8070 st
->stack
[i
].slot_type
[j
] = STACK_INVALID
;
8075 static void clean_verifier_state(struct bpf_verifier_env
*env
,
8076 struct bpf_verifier_state
*st
)
8080 if (st
->frame
[0]->regs
[0].live
& REG_LIVE_DONE
)
8081 /* all regs in this state in all frames were already marked */
8084 for (i
= 0; i
<= st
->curframe
; i
++)
8085 clean_func_state(env
, st
->frame
[i
]);
8088 /* the parentage chains form a tree.
8089 * the verifier states are added to state lists at given insn and
8090 * pushed into state stack for future exploration.
8091 * when the verifier reaches bpf_exit insn some of the verifer states
8092 * stored in the state lists have their final liveness state already,
8093 * but a lot of states will get revised from liveness point of view when
8094 * the verifier explores other branches.
8097 * 2: if r1 == 100 goto pc+1
8100 * when the verifier reaches exit insn the register r0 in the state list of
8101 * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
8102 * of insn 2 and goes exploring further. At the insn 4 it will walk the
8103 * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
8105 * Since the verifier pushes the branch states as it sees them while exploring
8106 * the program the condition of walking the branch instruction for the second
8107 * time means that all states below this branch were already explored and
8108 * their final liveness markes are already propagated.
8109 * Hence when the verifier completes the search of state list in is_state_visited()
8110 * we can call this clean_live_states() function to mark all liveness states
8111 * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
8113 * This function also clears the registers and stack for states that !READ
8114 * to simplify state merging.
8116 * Important note here that walking the same branch instruction in the callee
8117 * doesn't meant that the states are DONE. The verifier has to compare
8120 static void clean_live_states(struct bpf_verifier_env
*env
, int insn
,
8121 struct bpf_verifier_state
*cur
)
8123 struct bpf_verifier_state_list
*sl
;
8126 sl
= *explored_state(env
, insn
);
8128 if (sl
->state
.branches
)
8130 if (sl
->state
.insn_idx
!= insn
||
8131 sl
->state
.curframe
!= cur
->curframe
)
8133 for (i
= 0; i
<= cur
->curframe
; i
++)
8134 if (sl
->state
.frame
[i
]->callsite
!= cur
->frame
[i
]->callsite
)
8136 clean_verifier_state(env
, &sl
->state
);
8142 /* Returns true if (rold safe implies rcur safe) */
8143 static bool regsafe(struct bpf_reg_state
*rold
, struct bpf_reg_state
*rcur
,
8144 struct idpair
*idmap
)
8148 if (!(rold
->live
& REG_LIVE_READ
))
8149 /* explored state didn't use this */
8152 equal
= memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, parent
)) == 0;
8154 if (rold
->type
== PTR_TO_STACK
)
8155 /* two stack pointers are equal only if they're pointing to
8156 * the same stack frame, since fp-8 in foo != fp-8 in bar
8158 return equal
&& rold
->frameno
== rcur
->frameno
;
8163 if (rold
->type
== NOT_INIT
)
8164 /* explored state can't have used this */
8166 if (rcur
->type
== NOT_INIT
)
8168 switch (rold
->type
) {
8170 if (rcur
->type
== SCALAR_VALUE
) {
8171 if (!rold
->precise
&& !rcur
->precise
)
8173 /* new val must satisfy old val knowledge */
8174 return range_within(rold
, rcur
) &&
8175 tnum_in(rold
->var_off
, rcur
->var_off
);
8177 /* We're trying to use a pointer in place of a scalar.
8178 * Even if the scalar was unbounded, this could lead to
8179 * pointer leaks because scalars are allowed to leak
8180 * while pointers are not. We could make this safe in
8181 * special cases if root is calling us, but it's
8182 * probably not worth the hassle.
8186 case PTR_TO_MAP_VALUE
:
8187 /* If the new min/max/var_off satisfy the old ones and
8188 * everything else matches, we are OK.
8189 * 'id' is not compared, since it's only used for maps with
8190 * bpf_spin_lock inside map element and in such cases if
8191 * the rest of the prog is valid for one map element then
8192 * it's valid for all map elements regardless of the key
8193 * used in bpf_map_lookup()
8195 return memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, id
)) == 0 &&
8196 range_within(rold
, rcur
) &&
8197 tnum_in(rold
->var_off
, rcur
->var_off
);
8198 case PTR_TO_MAP_VALUE_OR_NULL
:
8199 /* a PTR_TO_MAP_VALUE could be safe to use as a
8200 * PTR_TO_MAP_VALUE_OR_NULL into the same map.
8201 * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL-
8202 * checked, doing so could have affected others with the same
8203 * id, and we can't check for that because we lost the id when
8204 * we converted to a PTR_TO_MAP_VALUE.
8206 if (rcur
->type
!= PTR_TO_MAP_VALUE_OR_NULL
)
8208 if (memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, id
)))
8210 /* Check our ids match any regs they're supposed to */
8211 return check_ids(rold
->id
, rcur
->id
, idmap
);
8212 case PTR_TO_PACKET_META
:
8214 if (rcur
->type
!= rold
->type
)
8216 /* We must have at least as much range as the old ptr
8217 * did, so that any accesses which were safe before are
8218 * still safe. This is true even if old range < old off,
8219 * since someone could have accessed through (ptr - k), or
8220 * even done ptr -= k in a register, to get a safe access.
8222 if (rold
->range
> rcur
->range
)
8224 /* If the offsets don't match, we can't trust our alignment;
8225 * nor can we be sure that we won't fall out of range.
8227 if (rold
->off
!= rcur
->off
)
8229 /* id relations must be preserved */
8230 if (rold
->id
&& !check_ids(rold
->id
, rcur
->id
, idmap
))
8232 /* new val must satisfy old val knowledge */
8233 return range_within(rold
, rcur
) &&
8234 tnum_in(rold
->var_off
, rcur
->var_off
);
8236 case CONST_PTR_TO_MAP
:
8237 case PTR_TO_PACKET_END
:
8238 case PTR_TO_FLOW_KEYS
:
8240 case PTR_TO_SOCKET_OR_NULL
:
8241 case PTR_TO_SOCK_COMMON
:
8242 case PTR_TO_SOCK_COMMON_OR_NULL
:
8243 case PTR_TO_TCP_SOCK
:
8244 case PTR_TO_TCP_SOCK_OR_NULL
:
8245 case PTR_TO_XDP_SOCK
:
8246 /* Only valid matches are exact, which memcmp() above
8247 * would have accepted
8250 /* Don't know what's going on, just say it's not safe */
8254 /* Shouldn't get here; if we do, say it's not safe */
8259 static bool stacksafe(struct bpf_func_state
*old
,
8260 struct bpf_func_state
*cur
,
8261 struct idpair
*idmap
)
8265 /* walk slots of the explored stack and ignore any additional
8266 * slots in the current stack, since explored(safe) state
8269 for (i
= 0; i
< old
->allocated_stack
; i
++) {
8270 spi
= i
/ BPF_REG_SIZE
;
8272 if (!(old
->stack
[spi
].spilled_ptr
.live
& REG_LIVE_READ
)) {
8273 i
+= BPF_REG_SIZE
- 1;
8274 /* explored state didn't use this */
8278 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_INVALID
)
8281 /* explored stack has more populated slots than current stack
8282 * and these slots were used
8284 if (i
>= cur
->allocated_stack
)
8287 /* if old state was safe with misc data in the stack
8288 * it will be safe with zero-initialized stack.
8289 * The opposite is not true
8291 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_MISC
&&
8292 cur
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_ZERO
)
8294 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] !=
8295 cur
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
])
8296 /* Ex: old explored (safe) state has STACK_SPILL in
8297 * this stack slot, but current has has STACK_MISC ->
8298 * this verifier states are not equivalent,
8299 * return false to continue verification of this path
8302 if (i
% BPF_REG_SIZE
)
8304 if (old
->stack
[spi
].slot_type
[0] != STACK_SPILL
)
8306 if (!regsafe(&old
->stack
[spi
].spilled_ptr
,
8307 &cur
->stack
[spi
].spilled_ptr
,
8309 /* when explored and current stack slot are both storing
8310 * spilled registers, check that stored pointers types
8311 * are the same as well.
8312 * Ex: explored safe path could have stored
8313 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
8314 * but current path has stored:
8315 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
8316 * such verifier states are not equivalent.
8317 * return false to continue verification of this path
8324 static bool refsafe(struct bpf_func_state
*old
, struct bpf_func_state
*cur
)
8326 if (old
->acquired_refs
!= cur
->acquired_refs
)
8328 return !memcmp(old
->refs
, cur
->refs
,
8329 sizeof(*old
->refs
) * old
->acquired_refs
);
8332 /* compare two verifier states
8334 * all states stored in state_list are known to be valid, since
8335 * verifier reached 'bpf_exit' instruction through them
8337 * this function is called when verifier exploring different branches of
8338 * execution popped from the state stack. If it sees an old state that has
8339 * more strict register state and more strict stack state then this execution
8340 * branch doesn't need to be explored further, since verifier already
8341 * concluded that more strict state leads to valid finish.
8343 * Therefore two states are equivalent if register state is more conservative
8344 * and explored stack state is more conservative than the current one.
8347 * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
8348 * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
8350 * In other words if current stack state (one being explored) has more
8351 * valid slots than old one that already passed validation, it means
8352 * the verifier can stop exploring and conclude that current state is valid too
8354 * Similarly with registers. If explored state has register type as invalid
8355 * whereas register type in current state is meaningful, it means that
8356 * the current state will reach 'bpf_exit' instruction safely
8358 static bool func_states_equal(struct bpf_func_state
*old
,
8359 struct bpf_func_state
*cur
)
8361 struct idpair
*idmap
;
8365 idmap
= kcalloc(ID_MAP_SIZE
, sizeof(struct idpair
), GFP_KERNEL
);
8366 /* If we failed to allocate the idmap, just say it's not safe */
8370 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
8371 if (!regsafe(&old
->regs
[i
], &cur
->regs
[i
], idmap
))
8375 if (!stacksafe(old
, cur
, idmap
))
8378 if (!refsafe(old
, cur
))
8386 static bool states_equal(struct bpf_verifier_env
*env
,
8387 struct bpf_verifier_state
*old
,
8388 struct bpf_verifier_state
*cur
)
8392 if (old
->curframe
!= cur
->curframe
)
8395 /* Verification state from speculative execution simulation
8396 * must never prune a non-speculative execution one.
8398 if (old
->speculative
&& !cur
->speculative
)
8401 if (old
->active_spin_lock
!= cur
->active_spin_lock
)
8404 /* for states to be equal callsites have to be the same
8405 * and all frame states need to be equivalent
8407 for (i
= 0; i
<= old
->curframe
; i
++) {
8408 if (old
->frame
[i
]->callsite
!= cur
->frame
[i
]->callsite
)
8410 if (!func_states_equal(old
->frame
[i
], cur
->frame
[i
]))
8416 /* Return 0 if no propagation happened. Return negative error code if error
8417 * happened. Otherwise, return the propagated bit.
8419 static int propagate_liveness_reg(struct bpf_verifier_env
*env
,
8420 struct bpf_reg_state
*reg
,
8421 struct bpf_reg_state
*parent_reg
)
8423 u8 parent_flag
= parent_reg
->live
& REG_LIVE_READ
;
8424 u8 flag
= reg
->live
& REG_LIVE_READ
;
8427 /* When comes here, read flags of PARENT_REG or REG could be any of
8428 * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
8429 * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
8431 if (parent_flag
== REG_LIVE_READ64
||
8432 /* Or if there is no read flag from REG. */
8434 /* Or if the read flag from REG is the same as PARENT_REG. */
8435 parent_flag
== flag
)
8438 err
= mark_reg_read(env
, reg
, parent_reg
, flag
);
8445 /* A write screens off any subsequent reads; but write marks come from the
8446 * straight-line code between a state and its parent. When we arrive at an
8447 * equivalent state (jump target or such) we didn't arrive by the straight-line
8448 * code, so read marks in the state must propagate to the parent regardless
8449 * of the state's write marks. That's what 'parent == state->parent' comparison
8450 * in mark_reg_read() is for.
8452 static int propagate_liveness(struct bpf_verifier_env
*env
,
8453 const struct bpf_verifier_state
*vstate
,
8454 struct bpf_verifier_state
*vparent
)
8456 struct bpf_reg_state
*state_reg
, *parent_reg
;
8457 struct bpf_func_state
*state
, *parent
;
8458 int i
, frame
, err
= 0;
8460 if (vparent
->curframe
!= vstate
->curframe
) {
8461 WARN(1, "propagate_live: parent frame %d current frame %d\n",
8462 vparent
->curframe
, vstate
->curframe
);
8465 /* Propagate read liveness of registers... */
8466 BUILD_BUG_ON(BPF_REG_FP
+ 1 != MAX_BPF_REG
);
8467 for (frame
= 0; frame
<= vstate
->curframe
; frame
++) {
8468 parent
= vparent
->frame
[frame
];
8469 state
= vstate
->frame
[frame
];
8470 parent_reg
= parent
->regs
;
8471 state_reg
= state
->regs
;
8472 /* We don't need to worry about FP liveness, it's read-only */
8473 for (i
= frame
< vstate
->curframe
? BPF_REG_6
: 0; i
< BPF_REG_FP
; i
++) {
8474 err
= propagate_liveness_reg(env
, &state_reg
[i
],
8478 if (err
== REG_LIVE_READ64
)
8479 mark_insn_zext(env
, &parent_reg
[i
]);
8482 /* Propagate stack slots. */
8483 for (i
= 0; i
< state
->allocated_stack
/ BPF_REG_SIZE
&&
8484 i
< parent
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
8485 parent_reg
= &parent
->stack
[i
].spilled_ptr
;
8486 state_reg
= &state
->stack
[i
].spilled_ptr
;
8487 err
= propagate_liveness_reg(env
, state_reg
,
8496 /* find precise scalars in the previous equivalent state and
8497 * propagate them into the current state
8499 static int propagate_precision(struct bpf_verifier_env
*env
,
8500 const struct bpf_verifier_state
*old
)
8502 struct bpf_reg_state
*state_reg
;
8503 struct bpf_func_state
*state
;
8506 state
= old
->frame
[old
->curframe
];
8507 state_reg
= state
->regs
;
8508 for (i
= 0; i
< BPF_REG_FP
; i
++, state_reg
++) {
8509 if (state_reg
->type
!= SCALAR_VALUE
||
8510 !state_reg
->precise
)
8512 if (env
->log
.level
& BPF_LOG_LEVEL2
)
8513 verbose(env
, "propagating r%d\n", i
);
8514 err
= mark_chain_precision(env
, i
);
8519 for (i
= 0; i
< state
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
8520 if (state
->stack
[i
].slot_type
[0] != STACK_SPILL
)
8522 state_reg
= &state
->stack
[i
].spilled_ptr
;
8523 if (state_reg
->type
!= SCALAR_VALUE
||
8524 !state_reg
->precise
)
8526 if (env
->log
.level
& BPF_LOG_LEVEL2
)
8527 verbose(env
, "propagating fp%d\n",
8528 (-i
- 1) * BPF_REG_SIZE
);
8529 err
= mark_chain_precision_stack(env
, i
);
8536 static bool states_maybe_looping(struct bpf_verifier_state
*old
,
8537 struct bpf_verifier_state
*cur
)
8539 struct bpf_func_state
*fold
, *fcur
;
8540 int i
, fr
= cur
->curframe
;
8542 if (old
->curframe
!= fr
)
8545 fold
= old
->frame
[fr
];
8546 fcur
= cur
->frame
[fr
];
8547 for (i
= 0; i
< MAX_BPF_REG
; i
++)
8548 if (memcmp(&fold
->regs
[i
], &fcur
->regs
[i
],
8549 offsetof(struct bpf_reg_state
, parent
)))
8555 static int is_state_visited(struct bpf_verifier_env
*env
, int insn_idx
)
8557 struct bpf_verifier_state_list
*new_sl
;
8558 struct bpf_verifier_state_list
*sl
, **pprev
;
8559 struct bpf_verifier_state
*cur
= env
->cur_state
, *new;
8560 int i
, j
, err
, states_cnt
= 0;
8561 bool add_new_state
= env
->test_state_freq
? true : false;
8563 cur
->last_insn_idx
= env
->prev_insn_idx
;
8564 if (!env
->insn_aux_data
[insn_idx
].prune_point
)
8565 /* this 'insn_idx' instruction wasn't marked, so we will not
8566 * be doing state search here
8570 /* bpf progs typically have pruning point every 4 instructions
8571 * http://vger.kernel.org/bpfconf2019.html#session-1
8572 * Do not add new state for future pruning if the verifier hasn't seen
8573 * at least 2 jumps and at least 8 instructions.
8574 * This heuristics helps decrease 'total_states' and 'peak_states' metric.
8575 * In tests that amounts to up to 50% reduction into total verifier
8576 * memory consumption and 20% verifier time speedup.
8578 if (env
->jmps_processed
- env
->prev_jmps_processed
>= 2 &&
8579 env
->insn_processed
- env
->prev_insn_processed
>= 8)
8580 add_new_state
= true;
8582 pprev
= explored_state(env
, insn_idx
);
8585 clean_live_states(env
, insn_idx
, cur
);
8589 if (sl
->state
.insn_idx
!= insn_idx
)
8591 if (sl
->state
.branches
) {
8592 if (states_maybe_looping(&sl
->state
, cur
) &&
8593 states_equal(env
, &sl
->state
, cur
)) {
8594 verbose_linfo(env
, insn_idx
, "; ");
8595 verbose(env
, "infinite loop detected at insn %d\n", insn_idx
);
8598 /* if the verifier is processing a loop, avoid adding new state
8599 * too often, since different loop iterations have distinct
8600 * states and may not help future pruning.
8601 * This threshold shouldn't be too low to make sure that
8602 * a loop with large bound will be rejected quickly.
8603 * The most abusive loop will be:
8605 * if r1 < 1000000 goto pc-2
8606 * 1M insn_procssed limit / 100 == 10k peak states.
8607 * This threshold shouldn't be too high either, since states
8608 * at the end of the loop are likely to be useful in pruning.
8610 if (env
->jmps_processed
- env
->prev_jmps_processed
< 20 &&
8611 env
->insn_processed
- env
->prev_insn_processed
< 100)
8612 add_new_state
= false;
8615 if (states_equal(env
, &sl
->state
, cur
)) {
8617 /* reached equivalent register/stack state,
8619 * Registers read by the continuation are read by us.
8620 * If we have any write marks in env->cur_state, they
8621 * will prevent corresponding reads in the continuation
8622 * from reaching our parent (an explored_state). Our
8623 * own state will get the read marks recorded, but
8624 * they'll be immediately forgotten as we're pruning
8625 * this state and will pop a new one.
8627 err
= propagate_liveness(env
, &sl
->state
, cur
);
8629 /* if previous state reached the exit with precision and
8630 * current state is equivalent to it (except precsion marks)
8631 * the precision needs to be propagated back in
8632 * the current state.
8634 err
= err
? : push_jmp_history(env
, cur
);
8635 err
= err
? : propagate_precision(env
, &sl
->state
);
8641 /* when new state is not going to be added do not increase miss count.
8642 * Otherwise several loop iterations will remove the state
8643 * recorded earlier. The goal of these heuristics is to have
8644 * states from some iterations of the loop (some in the beginning
8645 * and some at the end) to help pruning.
8649 /* heuristic to determine whether this state is beneficial
8650 * to keep checking from state equivalence point of view.
8651 * Higher numbers increase max_states_per_insn and verification time,
8652 * but do not meaningfully decrease insn_processed.
8654 if (sl
->miss_cnt
> sl
->hit_cnt
* 3 + 3) {
8655 /* the state is unlikely to be useful. Remove it to
8656 * speed up verification
8659 if (sl
->state
.frame
[0]->regs
[0].live
& REG_LIVE_DONE
) {
8660 u32 br
= sl
->state
.branches
;
8663 "BUG live_done but branches_to_explore %d\n",
8665 free_verifier_state(&sl
->state
, false);
8669 /* cannot free this state, since parentage chain may
8670 * walk it later. Add it for free_list instead to
8671 * be freed at the end of verification
8673 sl
->next
= env
->free_list
;
8674 env
->free_list
= sl
;
8684 if (env
->max_states_per_insn
< states_cnt
)
8685 env
->max_states_per_insn
= states_cnt
;
8687 if (!env
->bpf_capable
&& states_cnt
> BPF_COMPLEXITY_LIMIT_STATES
)
8688 return push_jmp_history(env
, cur
);
8691 return push_jmp_history(env
, cur
);
8693 /* There were no equivalent states, remember the current one.
8694 * Technically the current state is not proven to be safe yet,
8695 * but it will either reach outer most bpf_exit (which means it's safe)
8696 * or it will be rejected. When there are no loops the verifier won't be
8697 * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
8698 * again on the way to bpf_exit.
8699 * When looping the sl->state.branches will be > 0 and this state
8700 * will not be considered for equivalence until branches == 0.
8702 new_sl
= kzalloc(sizeof(struct bpf_verifier_state_list
), GFP_KERNEL
);
8705 env
->total_states
++;
8707 env
->prev_jmps_processed
= env
->jmps_processed
;
8708 env
->prev_insn_processed
= env
->insn_processed
;
8710 /* add new state to the head of linked list */
8711 new = &new_sl
->state
;
8712 err
= copy_verifier_state(new, cur
);
8714 free_verifier_state(new, false);
8718 new->insn_idx
= insn_idx
;
8719 WARN_ONCE(new->branches
!= 1,
8720 "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches
, insn_idx
);
8723 cur
->first_insn_idx
= insn_idx
;
8724 clear_jmp_history(cur
);
8725 new_sl
->next
= *explored_state(env
, insn_idx
);
8726 *explored_state(env
, insn_idx
) = new_sl
;
8727 /* connect new state to parentage chain. Current frame needs all
8728 * registers connected. Only r6 - r9 of the callers are alive (pushed
8729 * to the stack implicitly by JITs) so in callers' frames connect just
8730 * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
8731 * the state of the call instruction (with WRITTEN set), and r0 comes
8732 * from callee with its full parentage chain, anyway.
8734 /* clear write marks in current state: the writes we did are not writes
8735 * our child did, so they don't screen off its reads from us.
8736 * (There are no read marks in current state, because reads always mark
8737 * their parent and current state never has children yet. Only
8738 * explored_states can get read marks.)
8740 for (j
= 0; j
<= cur
->curframe
; j
++) {
8741 for (i
= j
< cur
->curframe
? BPF_REG_6
: 0; i
< BPF_REG_FP
; i
++)
8742 cur
->frame
[j
]->regs
[i
].parent
= &new->frame
[j
]->regs
[i
];
8743 for (i
= 0; i
< BPF_REG_FP
; i
++)
8744 cur
->frame
[j
]->regs
[i
].live
= REG_LIVE_NONE
;
8747 /* all stack frames are accessible from callee, clear them all */
8748 for (j
= 0; j
<= cur
->curframe
; j
++) {
8749 struct bpf_func_state
*frame
= cur
->frame
[j
];
8750 struct bpf_func_state
*newframe
= new->frame
[j
];
8752 for (i
= 0; i
< frame
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
8753 frame
->stack
[i
].spilled_ptr
.live
= REG_LIVE_NONE
;
8754 frame
->stack
[i
].spilled_ptr
.parent
=
8755 &newframe
->stack
[i
].spilled_ptr
;
8761 /* Return true if it's OK to have the same insn return a different type. */
8762 static bool reg_type_mismatch_ok(enum bpf_reg_type type
)
8767 case PTR_TO_SOCKET_OR_NULL
:
8768 case PTR_TO_SOCK_COMMON
:
8769 case PTR_TO_SOCK_COMMON_OR_NULL
:
8770 case PTR_TO_TCP_SOCK
:
8771 case PTR_TO_TCP_SOCK_OR_NULL
:
8772 case PTR_TO_XDP_SOCK
:
8774 case PTR_TO_BTF_ID_OR_NULL
:
8781 /* If an instruction was previously used with particular pointer types, then we
8782 * need to be careful to avoid cases such as the below, where it may be ok
8783 * for one branch accessing the pointer, but not ok for the other branch:
8788 * R1 = some_other_valid_ptr;
8791 * R2 = *(u32 *)(R1 + 0);
8793 static bool reg_type_mismatch(enum bpf_reg_type src
, enum bpf_reg_type prev
)
8795 return src
!= prev
&& (!reg_type_mismatch_ok(src
) ||
8796 !reg_type_mismatch_ok(prev
));
8799 static int do_check(struct bpf_verifier_env
*env
)
8801 bool pop_log
= !(env
->log
.level
& BPF_LOG_LEVEL2
);
8802 struct bpf_verifier_state
*state
= env
->cur_state
;
8803 struct bpf_insn
*insns
= env
->prog
->insnsi
;
8804 struct bpf_reg_state
*regs
;
8805 int insn_cnt
= env
->prog
->len
;
8806 bool do_print_state
= false;
8807 int prev_insn_idx
= -1;
8810 struct bpf_insn
*insn
;
8814 env
->prev_insn_idx
= prev_insn_idx
;
8815 if (env
->insn_idx
>= insn_cnt
) {
8816 verbose(env
, "invalid insn idx %d insn_cnt %d\n",
8817 env
->insn_idx
, insn_cnt
);
8821 insn
= &insns
[env
->insn_idx
];
8822 class = BPF_CLASS(insn
->code
);
8824 if (++env
->insn_processed
> BPF_COMPLEXITY_LIMIT_INSNS
) {
8826 "BPF program is too large. Processed %d insn\n",
8827 env
->insn_processed
);
8831 err
= is_state_visited(env
, env
->insn_idx
);
8835 /* found equivalent state, can prune the search */
8836 if (env
->log
.level
& BPF_LOG_LEVEL
) {
8838 verbose(env
, "\nfrom %d to %d%s: safe\n",
8839 env
->prev_insn_idx
, env
->insn_idx
,
8840 env
->cur_state
->speculative
?
8841 " (speculative execution)" : "");
8843 verbose(env
, "%d: safe\n", env
->insn_idx
);
8845 goto process_bpf_exit
;
8848 if (signal_pending(current
))
8854 if (env
->log
.level
& BPF_LOG_LEVEL2
||
8855 (env
->log
.level
& BPF_LOG_LEVEL
&& do_print_state
)) {
8856 if (env
->log
.level
& BPF_LOG_LEVEL2
)
8857 verbose(env
, "%d:", env
->insn_idx
);
8859 verbose(env
, "\nfrom %d to %d%s:",
8860 env
->prev_insn_idx
, env
->insn_idx
,
8861 env
->cur_state
->speculative
?
8862 " (speculative execution)" : "");
8863 print_verifier_state(env
, state
->frame
[state
->curframe
]);
8864 do_print_state
= false;
8867 if (env
->log
.level
& BPF_LOG_LEVEL
) {
8868 const struct bpf_insn_cbs cbs
= {
8869 .cb_print
= verbose
,
8870 .private_data
= env
,
8873 verbose_linfo(env
, env
->insn_idx
, "; ");
8874 verbose(env
, "%d: ", env
->insn_idx
);
8875 print_bpf_insn(&cbs
, insn
, env
->allow_ptr_leaks
);
8878 if (bpf_prog_is_dev_bound(env
->prog
->aux
)) {
8879 err
= bpf_prog_offload_verify_insn(env
, env
->insn_idx
,
8880 env
->prev_insn_idx
);
8885 regs
= cur_regs(env
);
8886 env
->insn_aux_data
[env
->insn_idx
].seen
= env
->pass_cnt
;
8887 prev_insn_idx
= env
->insn_idx
;
8889 if (class == BPF_ALU
|| class == BPF_ALU64
) {
8890 err
= check_alu_op(env
, insn
);
8894 } else if (class == BPF_LDX
) {
8895 enum bpf_reg_type
*prev_src_type
, src_reg_type
;
8897 /* check for reserved fields is already done */
8899 /* check src operand */
8900 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
8904 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
8908 src_reg_type
= regs
[insn
->src_reg
].type
;
8910 /* check that memory (src_reg + off) is readable,
8911 * the state of dst_reg will be updated by this func
8913 err
= check_mem_access(env
, env
->insn_idx
, insn
->src_reg
,
8914 insn
->off
, BPF_SIZE(insn
->code
),
8915 BPF_READ
, insn
->dst_reg
, false);
8919 prev_src_type
= &env
->insn_aux_data
[env
->insn_idx
].ptr_type
;
8921 if (*prev_src_type
== NOT_INIT
) {
8923 * dst_reg = *(u32 *)(src_reg + off)
8924 * save type to validate intersecting paths
8926 *prev_src_type
= src_reg_type
;
8928 } else if (reg_type_mismatch(src_reg_type
, *prev_src_type
)) {
8929 /* ABuser program is trying to use the same insn
8930 * dst_reg = *(u32*) (src_reg + off)
8931 * with different pointer types:
8932 * src_reg == ctx in one branch and
8933 * src_reg == stack|map in some other branch.
8936 verbose(env
, "same insn cannot be used with different pointers\n");
8940 } else if (class == BPF_STX
) {
8941 enum bpf_reg_type
*prev_dst_type
, dst_reg_type
;
8943 if (BPF_MODE(insn
->code
) == BPF_XADD
) {
8944 err
= check_xadd(env
, env
->insn_idx
, insn
);
8951 /* check src1 operand */
8952 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
8955 /* check src2 operand */
8956 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
8960 dst_reg_type
= regs
[insn
->dst_reg
].type
;
8962 /* check that memory (dst_reg + off) is writeable */
8963 err
= check_mem_access(env
, env
->insn_idx
, insn
->dst_reg
,
8964 insn
->off
, BPF_SIZE(insn
->code
),
8965 BPF_WRITE
, insn
->src_reg
, false);
8969 prev_dst_type
= &env
->insn_aux_data
[env
->insn_idx
].ptr_type
;
8971 if (*prev_dst_type
== NOT_INIT
) {
8972 *prev_dst_type
= dst_reg_type
;
8973 } else if (reg_type_mismatch(dst_reg_type
, *prev_dst_type
)) {
8974 verbose(env
, "same insn cannot be used with different pointers\n");
8978 } else if (class == BPF_ST
) {
8979 if (BPF_MODE(insn
->code
) != BPF_MEM
||
8980 insn
->src_reg
!= BPF_REG_0
) {
8981 verbose(env
, "BPF_ST uses reserved fields\n");
8984 /* check src operand */
8985 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
8989 if (is_ctx_reg(env
, insn
->dst_reg
)) {
8990 verbose(env
, "BPF_ST stores into R%d %s is not allowed\n",
8992 reg_type_str
[reg_state(env
, insn
->dst_reg
)->type
]);
8996 /* check that memory (dst_reg + off) is writeable */
8997 err
= check_mem_access(env
, env
->insn_idx
, insn
->dst_reg
,
8998 insn
->off
, BPF_SIZE(insn
->code
),
8999 BPF_WRITE
, -1, false);
9003 } else if (class == BPF_JMP
|| class == BPF_JMP32
) {
9004 u8 opcode
= BPF_OP(insn
->code
);
9006 env
->jmps_processed
++;
9007 if (opcode
== BPF_CALL
) {
9008 if (BPF_SRC(insn
->code
) != BPF_K
||
9010 (insn
->src_reg
!= BPF_REG_0
&&
9011 insn
->src_reg
!= BPF_PSEUDO_CALL
) ||
9012 insn
->dst_reg
!= BPF_REG_0
||
9013 class == BPF_JMP32
) {
9014 verbose(env
, "BPF_CALL uses reserved fields\n");
9018 if (env
->cur_state
->active_spin_lock
&&
9019 (insn
->src_reg
== BPF_PSEUDO_CALL
||
9020 insn
->imm
!= BPF_FUNC_spin_unlock
)) {
9021 verbose(env
, "function calls are not allowed while holding a lock\n");
9024 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
9025 err
= check_func_call(env
, insn
, &env
->insn_idx
);
9027 err
= check_helper_call(env
, insn
->imm
, env
->insn_idx
);
9031 } else if (opcode
== BPF_JA
) {
9032 if (BPF_SRC(insn
->code
) != BPF_K
||
9034 insn
->src_reg
!= BPF_REG_0
||
9035 insn
->dst_reg
!= BPF_REG_0
||
9036 class == BPF_JMP32
) {
9037 verbose(env
, "BPF_JA uses reserved fields\n");
9041 env
->insn_idx
+= insn
->off
+ 1;
9044 } else if (opcode
== BPF_EXIT
) {
9045 if (BPF_SRC(insn
->code
) != BPF_K
||
9047 insn
->src_reg
!= BPF_REG_0
||
9048 insn
->dst_reg
!= BPF_REG_0
||
9049 class == BPF_JMP32
) {
9050 verbose(env
, "BPF_EXIT uses reserved fields\n");
9054 if (env
->cur_state
->active_spin_lock
) {
9055 verbose(env
, "bpf_spin_unlock is missing\n");
9059 if (state
->curframe
) {
9060 /* exit from nested function */
9061 err
= prepare_func_exit(env
, &env
->insn_idx
);
9064 do_print_state
= true;
9068 err
= check_reference_leak(env
);
9072 err
= check_return_code(env
);
9076 update_branch_counts(env
, env
->cur_state
);
9077 err
= pop_stack(env
, &prev_insn_idx
,
9078 &env
->insn_idx
, pop_log
);
9084 do_print_state
= true;
9088 err
= check_cond_jmp_op(env
, insn
, &env
->insn_idx
);
9092 } else if (class == BPF_LD
) {
9093 u8 mode
= BPF_MODE(insn
->code
);
9095 if (mode
== BPF_ABS
|| mode
== BPF_IND
) {
9096 err
= check_ld_abs(env
, insn
);
9100 } else if (mode
== BPF_IMM
) {
9101 err
= check_ld_imm(env
, insn
);
9106 env
->insn_aux_data
[env
->insn_idx
].seen
= env
->pass_cnt
;
9108 verbose(env
, "invalid BPF_LD mode\n");
9112 verbose(env
, "unknown insn class %d\n", class);
9122 static int check_map_prealloc(struct bpf_map
*map
)
9124 return (map
->map_type
!= BPF_MAP_TYPE_HASH
&&
9125 map
->map_type
!= BPF_MAP_TYPE_PERCPU_HASH
&&
9126 map
->map_type
!= BPF_MAP_TYPE_HASH_OF_MAPS
) ||
9127 !(map
->map_flags
& BPF_F_NO_PREALLOC
);
9130 static bool is_tracing_prog_type(enum bpf_prog_type type
)
9133 case BPF_PROG_TYPE_KPROBE
:
9134 case BPF_PROG_TYPE_TRACEPOINT
:
9135 case BPF_PROG_TYPE_PERF_EVENT
:
9136 case BPF_PROG_TYPE_RAW_TRACEPOINT
:
9143 static bool is_preallocated_map(struct bpf_map
*map
)
9145 if (!check_map_prealloc(map
))
9147 if (map
->inner_map_meta
&& !check_map_prealloc(map
->inner_map_meta
))
9152 static int check_map_prog_compatibility(struct bpf_verifier_env
*env
,
9153 struct bpf_map
*map
,
9154 struct bpf_prog
*prog
)
9158 * Validate that trace type programs use preallocated hash maps.
9160 * For programs attached to PERF events this is mandatory as the
9161 * perf NMI can hit any arbitrary code sequence.
9163 * All other trace types using preallocated hash maps are unsafe as
9164 * well because tracepoint or kprobes can be inside locked regions
9165 * of the memory allocator or at a place where a recursion into the
9166 * memory allocator would see inconsistent state.
9168 * On RT enabled kernels run-time allocation of all trace type
9169 * programs is strictly prohibited due to lock type constraints. On
9170 * !RT kernels it is allowed for backwards compatibility reasons for
9171 * now, but warnings are emitted so developers are made aware of
9172 * the unsafety and can fix their programs before this is enforced.
9174 if (is_tracing_prog_type(prog
->type
) && !is_preallocated_map(map
)) {
9175 if (prog
->type
== BPF_PROG_TYPE_PERF_EVENT
) {
9176 verbose(env
, "perf_event programs can only use preallocated hash map\n");
9179 if (IS_ENABLED(CONFIG_PREEMPT_RT
)) {
9180 verbose(env
, "trace type programs can only use preallocated hash map\n");
9183 WARN_ONCE(1, "trace type BPF program uses run-time allocation\n");
9184 verbose(env
, "trace type programs with run-time allocated hash maps are unsafe. Switch to preallocated hash maps.\n");
9187 if ((is_tracing_prog_type(prog
->type
) ||
9188 prog
->type
== BPF_PROG_TYPE_SOCKET_FILTER
) &&
9189 map_value_has_spin_lock(map
)) {
9190 verbose(env
, "tracing progs cannot use bpf_spin_lock yet\n");
9194 if ((bpf_prog_is_dev_bound(prog
->aux
) || bpf_map_is_dev_bound(map
)) &&
9195 !bpf_offload_prog_map_match(prog
, map
)) {
9196 verbose(env
, "offload device mismatch between prog and map\n");
9200 if (map
->map_type
== BPF_MAP_TYPE_STRUCT_OPS
) {
9201 verbose(env
, "bpf_struct_ops map cannot be used in prog\n");
9208 static bool bpf_map_is_cgroup_storage(struct bpf_map
*map
)
9210 return (map
->map_type
== BPF_MAP_TYPE_CGROUP_STORAGE
||
9211 map
->map_type
== BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
);
9214 /* look for pseudo eBPF instructions that access map FDs and
9215 * replace them with actual map pointers
9217 static int replace_map_fd_with_map_ptr(struct bpf_verifier_env
*env
)
9219 struct bpf_insn
*insn
= env
->prog
->insnsi
;
9220 int insn_cnt
= env
->prog
->len
;
9223 err
= bpf_prog_calc_tag(env
->prog
);
9227 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
9228 if (BPF_CLASS(insn
->code
) == BPF_LDX
&&
9229 (BPF_MODE(insn
->code
) != BPF_MEM
|| insn
->imm
!= 0)) {
9230 verbose(env
, "BPF_LDX uses reserved fields\n");
9234 if (BPF_CLASS(insn
->code
) == BPF_STX
&&
9235 ((BPF_MODE(insn
->code
) != BPF_MEM
&&
9236 BPF_MODE(insn
->code
) != BPF_XADD
) || insn
->imm
!= 0)) {
9237 verbose(env
, "BPF_STX uses reserved fields\n");
9241 if (insn
[0].code
== (BPF_LD
| BPF_IMM
| BPF_DW
)) {
9242 struct bpf_insn_aux_data
*aux
;
9243 struct bpf_map
*map
;
9247 if (i
== insn_cnt
- 1 || insn
[1].code
!= 0 ||
9248 insn
[1].dst_reg
!= 0 || insn
[1].src_reg
!= 0 ||
9250 verbose(env
, "invalid bpf_ld_imm64 insn\n");
9254 if (insn
[0].src_reg
== 0)
9255 /* valid generic load 64-bit imm */
9258 /* In final convert_pseudo_ld_imm64() step, this is
9259 * converted into regular 64-bit imm load insn.
9261 if ((insn
[0].src_reg
!= BPF_PSEUDO_MAP_FD
&&
9262 insn
[0].src_reg
!= BPF_PSEUDO_MAP_VALUE
) ||
9263 (insn
[0].src_reg
== BPF_PSEUDO_MAP_FD
&&
9264 insn
[1].imm
!= 0)) {
9266 "unrecognized bpf_ld_imm64 insn\n");
9270 f
= fdget(insn
[0].imm
);
9271 map
= __bpf_map_get(f
);
9273 verbose(env
, "fd %d is not pointing to valid bpf_map\n",
9275 return PTR_ERR(map
);
9278 err
= check_map_prog_compatibility(env
, map
, env
->prog
);
9284 aux
= &env
->insn_aux_data
[i
];
9285 if (insn
->src_reg
== BPF_PSEUDO_MAP_FD
) {
9286 addr
= (unsigned long)map
;
9288 u32 off
= insn
[1].imm
;
9290 if (off
>= BPF_MAX_VAR_OFF
) {
9291 verbose(env
, "direct value offset of %u is not allowed\n", off
);
9296 if (!map
->ops
->map_direct_value_addr
) {
9297 verbose(env
, "no direct value access support for this map type\n");
9302 err
= map
->ops
->map_direct_value_addr(map
, &addr
, off
);
9304 verbose(env
, "invalid access to map value pointer, value_size=%u off=%u\n",
9305 map
->value_size
, off
);
9314 insn
[0].imm
= (u32
)addr
;
9315 insn
[1].imm
= addr
>> 32;
9317 /* check whether we recorded this map already */
9318 for (j
= 0; j
< env
->used_map_cnt
; j
++) {
9319 if (env
->used_maps
[j
] == map
) {
9326 if (env
->used_map_cnt
>= MAX_USED_MAPS
) {
9331 /* hold the map. If the program is rejected by verifier,
9332 * the map will be released by release_maps() or it
9333 * will be used by the valid program until it's unloaded
9334 * and all maps are released in free_used_maps()
9338 aux
->map_index
= env
->used_map_cnt
;
9339 env
->used_maps
[env
->used_map_cnt
++] = map
;
9341 if (bpf_map_is_cgroup_storage(map
) &&
9342 bpf_cgroup_storage_assign(env
->prog
->aux
, map
)) {
9343 verbose(env
, "only one cgroup storage of each type is allowed\n");
9355 /* Basic sanity check before we invest more work here. */
9356 if (!bpf_opcode_in_insntable(insn
->code
)) {
9357 verbose(env
, "unknown opcode %02x\n", insn
->code
);
9362 /* now all pseudo BPF_LD_IMM64 instructions load valid
9363 * 'struct bpf_map *' into a register instead of user map_fd.
9364 * These pointers will be used later by verifier to validate map access.
9369 /* drop refcnt of maps used by the rejected program */
9370 static void release_maps(struct bpf_verifier_env
*env
)
9372 __bpf_free_used_maps(env
->prog
->aux
, env
->used_maps
,
9376 /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
9377 static void convert_pseudo_ld_imm64(struct bpf_verifier_env
*env
)
9379 struct bpf_insn
*insn
= env
->prog
->insnsi
;
9380 int insn_cnt
= env
->prog
->len
;
9383 for (i
= 0; i
< insn_cnt
; i
++, insn
++)
9384 if (insn
->code
== (BPF_LD
| BPF_IMM
| BPF_DW
))
9388 /* single env->prog->insni[off] instruction was replaced with the range
9389 * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying
9390 * [0, off) and [off, end) to new locations, so the patched range stays zero
9392 static int adjust_insn_aux_data(struct bpf_verifier_env
*env
,
9393 struct bpf_prog
*new_prog
, u32 off
, u32 cnt
)
9395 struct bpf_insn_aux_data
*new_data
, *old_data
= env
->insn_aux_data
;
9396 struct bpf_insn
*insn
= new_prog
->insnsi
;
9400 /* aux info at OFF always needs adjustment, no matter fast path
9401 * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
9402 * original insn at old prog.
9404 old_data
[off
].zext_dst
= insn_has_def32(env
, insn
+ off
+ cnt
- 1);
9408 prog_len
= new_prog
->len
;
9409 new_data
= vzalloc(array_size(prog_len
,
9410 sizeof(struct bpf_insn_aux_data
)));
9413 memcpy(new_data
, old_data
, sizeof(struct bpf_insn_aux_data
) * off
);
9414 memcpy(new_data
+ off
+ cnt
- 1, old_data
+ off
,
9415 sizeof(struct bpf_insn_aux_data
) * (prog_len
- off
- cnt
+ 1));
9416 for (i
= off
; i
< off
+ cnt
- 1; i
++) {
9417 new_data
[i
].seen
= env
->pass_cnt
;
9418 new_data
[i
].zext_dst
= insn_has_def32(env
, insn
+ i
);
9420 env
->insn_aux_data
= new_data
;
9425 static void adjust_subprog_starts(struct bpf_verifier_env
*env
, u32 off
, u32 len
)
9431 /* NOTE: fake 'exit' subprog should be updated as well. */
9432 for (i
= 0; i
<= env
->subprog_cnt
; i
++) {
9433 if (env
->subprog_info
[i
].start
<= off
)
9435 env
->subprog_info
[i
].start
+= len
- 1;
9439 static struct bpf_prog
*bpf_patch_insn_data(struct bpf_verifier_env
*env
, u32 off
,
9440 const struct bpf_insn
*patch
, u32 len
)
9442 struct bpf_prog
*new_prog
;
9444 new_prog
= bpf_patch_insn_single(env
->prog
, off
, patch
, len
);
9445 if (IS_ERR(new_prog
)) {
9446 if (PTR_ERR(new_prog
) == -ERANGE
)
9448 "insn %d cannot be patched due to 16-bit range\n",
9449 env
->insn_aux_data
[off
].orig_idx
);
9452 if (adjust_insn_aux_data(env
, new_prog
, off
, len
))
9454 adjust_subprog_starts(env
, off
, len
);
9458 static int adjust_subprog_starts_after_remove(struct bpf_verifier_env
*env
,
9463 /* find first prog starting at or after off (first to remove) */
9464 for (i
= 0; i
< env
->subprog_cnt
; i
++)
9465 if (env
->subprog_info
[i
].start
>= off
)
9467 /* find first prog starting at or after off + cnt (first to stay) */
9468 for (j
= i
; j
< env
->subprog_cnt
; j
++)
9469 if (env
->subprog_info
[j
].start
>= off
+ cnt
)
9471 /* if j doesn't start exactly at off + cnt, we are just removing
9472 * the front of previous prog
9474 if (env
->subprog_info
[j
].start
!= off
+ cnt
)
9478 struct bpf_prog_aux
*aux
= env
->prog
->aux
;
9481 /* move fake 'exit' subprog as well */
9482 move
= env
->subprog_cnt
+ 1 - j
;
9484 memmove(env
->subprog_info
+ i
,
9485 env
->subprog_info
+ j
,
9486 sizeof(*env
->subprog_info
) * move
);
9487 env
->subprog_cnt
-= j
- i
;
9489 /* remove func_info */
9490 if (aux
->func_info
) {
9491 move
= aux
->func_info_cnt
- j
;
9493 memmove(aux
->func_info
+ i
,
9495 sizeof(*aux
->func_info
) * move
);
9496 aux
->func_info_cnt
-= j
- i
;
9497 /* func_info->insn_off is set after all code rewrites,
9498 * in adjust_btf_func() - no need to adjust
9502 /* convert i from "first prog to remove" to "first to adjust" */
9503 if (env
->subprog_info
[i
].start
== off
)
9507 /* update fake 'exit' subprog as well */
9508 for (; i
<= env
->subprog_cnt
; i
++)
9509 env
->subprog_info
[i
].start
-= cnt
;
9514 static int bpf_adj_linfo_after_remove(struct bpf_verifier_env
*env
, u32 off
,
9517 struct bpf_prog
*prog
= env
->prog
;
9518 u32 i
, l_off
, l_cnt
, nr_linfo
;
9519 struct bpf_line_info
*linfo
;
9521 nr_linfo
= prog
->aux
->nr_linfo
;
9525 linfo
= prog
->aux
->linfo
;
9527 /* find first line info to remove, count lines to be removed */
9528 for (i
= 0; i
< nr_linfo
; i
++)
9529 if (linfo
[i
].insn_off
>= off
)
9534 for (; i
< nr_linfo
; i
++)
9535 if (linfo
[i
].insn_off
< off
+ cnt
)
9540 /* First live insn doesn't match first live linfo, it needs to "inherit"
9541 * last removed linfo. prog is already modified, so prog->len == off
9542 * means no live instructions after (tail of the program was removed).
9544 if (prog
->len
!= off
&& l_cnt
&&
9545 (i
== nr_linfo
|| linfo
[i
].insn_off
!= off
+ cnt
)) {
9547 linfo
[--i
].insn_off
= off
+ cnt
;
9550 /* remove the line info which refer to the removed instructions */
9552 memmove(linfo
+ l_off
, linfo
+ i
,
9553 sizeof(*linfo
) * (nr_linfo
- i
));
9555 prog
->aux
->nr_linfo
-= l_cnt
;
9556 nr_linfo
= prog
->aux
->nr_linfo
;
9559 /* pull all linfo[i].insn_off >= off + cnt in by cnt */
9560 for (i
= l_off
; i
< nr_linfo
; i
++)
9561 linfo
[i
].insn_off
-= cnt
;
9563 /* fix up all subprogs (incl. 'exit') which start >= off */
9564 for (i
= 0; i
<= env
->subprog_cnt
; i
++)
9565 if (env
->subprog_info
[i
].linfo_idx
> l_off
) {
9566 /* program may have started in the removed region but
9567 * may not be fully removed
9569 if (env
->subprog_info
[i
].linfo_idx
>= l_off
+ l_cnt
)
9570 env
->subprog_info
[i
].linfo_idx
-= l_cnt
;
9572 env
->subprog_info
[i
].linfo_idx
= l_off
;
9578 static int verifier_remove_insns(struct bpf_verifier_env
*env
, u32 off
, u32 cnt
)
9580 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
9581 unsigned int orig_prog_len
= env
->prog
->len
;
9584 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
9585 bpf_prog_offload_remove_insns(env
, off
, cnt
);
9587 err
= bpf_remove_insns(env
->prog
, off
, cnt
);
9591 err
= adjust_subprog_starts_after_remove(env
, off
, cnt
);
9595 err
= bpf_adj_linfo_after_remove(env
, off
, cnt
);
9599 memmove(aux_data
+ off
, aux_data
+ off
+ cnt
,
9600 sizeof(*aux_data
) * (orig_prog_len
- off
- cnt
));
9605 /* The verifier does more data flow analysis than llvm and will not
9606 * explore branches that are dead at run time. Malicious programs can
9607 * have dead code too. Therefore replace all dead at-run-time code
9610 * Just nops are not optimal, e.g. if they would sit at the end of the
9611 * program and through another bug we would manage to jump there, then
9612 * we'd execute beyond program memory otherwise. Returning exception
9613 * code also wouldn't work since we can have subprogs where the dead
9614 * code could be located.
9616 static void sanitize_dead_code(struct bpf_verifier_env
*env
)
9618 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
9619 struct bpf_insn trap
= BPF_JMP_IMM(BPF_JA
, 0, 0, -1);
9620 struct bpf_insn
*insn
= env
->prog
->insnsi
;
9621 const int insn_cnt
= env
->prog
->len
;
9624 for (i
= 0; i
< insn_cnt
; i
++) {
9625 if (aux_data
[i
].seen
)
9627 memcpy(insn
+ i
, &trap
, sizeof(trap
));
9631 static bool insn_is_cond_jump(u8 code
)
9635 if (BPF_CLASS(code
) == BPF_JMP32
)
9638 if (BPF_CLASS(code
) != BPF_JMP
)
9642 return op
!= BPF_JA
&& op
!= BPF_EXIT
&& op
!= BPF_CALL
;
9645 static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env
*env
)
9647 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
9648 struct bpf_insn ja
= BPF_JMP_IMM(BPF_JA
, 0, 0, 0);
9649 struct bpf_insn
*insn
= env
->prog
->insnsi
;
9650 const int insn_cnt
= env
->prog
->len
;
9653 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
9654 if (!insn_is_cond_jump(insn
->code
))
9657 if (!aux_data
[i
+ 1].seen
)
9659 else if (!aux_data
[i
+ 1 + insn
->off
].seen
)
9664 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
9665 bpf_prog_offload_replace_insn(env
, i
, &ja
);
9667 memcpy(insn
, &ja
, sizeof(ja
));
9671 static int opt_remove_dead_code(struct bpf_verifier_env
*env
)
9673 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
9674 int insn_cnt
= env
->prog
->len
;
9677 for (i
= 0; i
< insn_cnt
; i
++) {
9681 while (i
+ j
< insn_cnt
&& !aux_data
[i
+ j
].seen
)
9686 err
= verifier_remove_insns(env
, i
, j
);
9689 insn_cnt
= env
->prog
->len
;
9695 static int opt_remove_nops(struct bpf_verifier_env
*env
)
9697 const struct bpf_insn ja
= BPF_JMP_IMM(BPF_JA
, 0, 0, 0);
9698 struct bpf_insn
*insn
= env
->prog
->insnsi
;
9699 int insn_cnt
= env
->prog
->len
;
9702 for (i
= 0; i
< insn_cnt
; i
++) {
9703 if (memcmp(&insn
[i
], &ja
, sizeof(ja
)))
9706 err
= verifier_remove_insns(env
, i
, 1);
9716 static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env
*env
,
9717 const union bpf_attr
*attr
)
9719 struct bpf_insn
*patch
, zext_patch
[2], rnd_hi32_patch
[4];
9720 struct bpf_insn_aux_data
*aux
= env
->insn_aux_data
;
9721 int i
, patch_len
, delta
= 0, len
= env
->prog
->len
;
9722 struct bpf_insn
*insns
= env
->prog
->insnsi
;
9723 struct bpf_prog
*new_prog
;
9726 rnd_hi32
= attr
->prog_flags
& BPF_F_TEST_RND_HI32
;
9727 zext_patch
[1] = BPF_ZEXT_REG(0);
9728 rnd_hi32_patch
[1] = BPF_ALU64_IMM(BPF_MOV
, BPF_REG_AX
, 0);
9729 rnd_hi32_patch
[2] = BPF_ALU64_IMM(BPF_LSH
, BPF_REG_AX
, 32);
9730 rnd_hi32_patch
[3] = BPF_ALU64_REG(BPF_OR
, 0, BPF_REG_AX
);
9731 for (i
= 0; i
< len
; i
++) {
9732 int adj_idx
= i
+ delta
;
9733 struct bpf_insn insn
;
9735 insn
= insns
[adj_idx
];
9736 if (!aux
[adj_idx
].zext_dst
) {
9744 class = BPF_CLASS(code
);
9745 if (insn_no_def(&insn
))
9748 /* NOTE: arg "reg" (the fourth one) is only used for
9749 * BPF_STX which has been ruled out in above
9750 * check, it is safe to pass NULL here.
9752 if (is_reg64(env
, &insn
, insn
.dst_reg
, NULL
, DST_OP
)) {
9753 if (class == BPF_LD
&&
9754 BPF_MODE(code
) == BPF_IMM
)
9759 /* ctx load could be transformed into wider load. */
9760 if (class == BPF_LDX
&&
9761 aux
[adj_idx
].ptr_type
== PTR_TO_CTX
)
9764 imm_rnd
= get_random_int();
9765 rnd_hi32_patch
[0] = insn
;
9766 rnd_hi32_patch
[1].imm
= imm_rnd
;
9767 rnd_hi32_patch
[3].dst_reg
= insn
.dst_reg
;
9768 patch
= rnd_hi32_patch
;
9770 goto apply_patch_buffer
;
9773 if (!bpf_jit_needs_zext())
9776 zext_patch
[0] = insn
;
9777 zext_patch
[1].dst_reg
= insn
.dst_reg
;
9778 zext_patch
[1].src_reg
= insn
.dst_reg
;
9782 new_prog
= bpf_patch_insn_data(env
, adj_idx
, patch
, patch_len
);
9785 env
->prog
= new_prog
;
9786 insns
= new_prog
->insnsi
;
9787 aux
= env
->insn_aux_data
;
9788 delta
+= patch_len
- 1;
9794 /* convert load instructions that access fields of a context type into a
9795 * sequence of instructions that access fields of the underlying structure:
9796 * struct __sk_buff -> struct sk_buff
9797 * struct bpf_sock_ops -> struct sock
9799 static int convert_ctx_accesses(struct bpf_verifier_env
*env
)
9801 const struct bpf_verifier_ops
*ops
= env
->ops
;
9802 int i
, cnt
, size
, ctx_field_size
, delta
= 0;
9803 const int insn_cnt
= env
->prog
->len
;
9804 struct bpf_insn insn_buf
[16], *insn
;
9805 u32 target_size
, size_default
, off
;
9806 struct bpf_prog
*new_prog
;
9807 enum bpf_access_type type
;
9808 bool is_narrower_load
;
9810 if (ops
->gen_prologue
|| env
->seen_direct_write
) {
9811 if (!ops
->gen_prologue
) {
9812 verbose(env
, "bpf verifier is misconfigured\n");
9815 cnt
= ops
->gen_prologue(insn_buf
, env
->seen_direct_write
,
9817 if (cnt
>= ARRAY_SIZE(insn_buf
)) {
9818 verbose(env
, "bpf verifier is misconfigured\n");
9821 new_prog
= bpf_patch_insn_data(env
, 0, insn_buf
, cnt
);
9825 env
->prog
= new_prog
;
9830 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
9833 insn
= env
->prog
->insnsi
+ delta
;
9835 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
9836 bpf_convert_ctx_access_t convert_ctx_access
;
9838 if (insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_B
) ||
9839 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_H
) ||
9840 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_W
) ||
9841 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_DW
))
9843 else if (insn
->code
== (BPF_STX
| BPF_MEM
| BPF_B
) ||
9844 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_H
) ||
9845 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_W
) ||
9846 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_DW
))
9851 if (type
== BPF_WRITE
&&
9852 env
->insn_aux_data
[i
+ delta
].sanitize_stack_off
) {
9853 struct bpf_insn patch
[] = {
9854 /* Sanitize suspicious stack slot with zero.
9855 * There are no memory dependencies for this store,
9856 * since it's only using frame pointer and immediate
9859 BPF_ST_MEM(BPF_DW
, BPF_REG_FP
,
9860 env
->insn_aux_data
[i
+ delta
].sanitize_stack_off
,
9862 /* the original STX instruction will immediately
9863 * overwrite the same stack slot with appropriate value
9868 cnt
= ARRAY_SIZE(patch
);
9869 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, patch
, cnt
);
9874 env
->prog
= new_prog
;
9875 insn
= new_prog
->insnsi
+ i
+ delta
;
9879 switch (env
->insn_aux_data
[i
+ delta
].ptr_type
) {
9881 if (!ops
->convert_ctx_access
)
9883 convert_ctx_access
= ops
->convert_ctx_access
;
9886 case PTR_TO_SOCK_COMMON
:
9887 convert_ctx_access
= bpf_sock_convert_ctx_access
;
9889 case PTR_TO_TCP_SOCK
:
9890 convert_ctx_access
= bpf_tcp_sock_convert_ctx_access
;
9892 case PTR_TO_XDP_SOCK
:
9893 convert_ctx_access
= bpf_xdp_sock_convert_ctx_access
;
9896 if (type
== BPF_READ
) {
9897 insn
->code
= BPF_LDX
| BPF_PROBE_MEM
|
9898 BPF_SIZE((insn
)->code
);
9899 env
->prog
->aux
->num_exentries
++;
9900 } else if (env
->prog
->type
!= BPF_PROG_TYPE_STRUCT_OPS
) {
9901 verbose(env
, "Writes through BTF pointers are not allowed\n");
9909 ctx_field_size
= env
->insn_aux_data
[i
+ delta
].ctx_field_size
;
9910 size
= BPF_LDST_BYTES(insn
);
9912 /* If the read access is a narrower load of the field,
9913 * convert to a 4/8-byte load, to minimum program type specific
9914 * convert_ctx_access changes. If conversion is successful,
9915 * we will apply proper mask to the result.
9917 is_narrower_load
= size
< ctx_field_size
;
9918 size_default
= bpf_ctx_off_adjust_machine(ctx_field_size
);
9920 if (is_narrower_load
) {
9923 if (type
== BPF_WRITE
) {
9924 verbose(env
, "bpf verifier narrow ctx access misconfigured\n");
9929 if (ctx_field_size
== 4)
9931 else if (ctx_field_size
== 8)
9934 insn
->off
= off
& ~(size_default
- 1);
9935 insn
->code
= BPF_LDX
| BPF_MEM
| size_code
;
9939 cnt
= convert_ctx_access(type
, insn
, insn_buf
, env
->prog
,
9941 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
) ||
9942 (ctx_field_size
&& !target_size
)) {
9943 verbose(env
, "bpf verifier is misconfigured\n");
9947 if (is_narrower_load
&& size
< target_size
) {
9948 u8 shift
= bpf_ctx_narrow_access_offset(
9949 off
, size
, size_default
) * 8;
9950 if (ctx_field_size
<= 4) {
9952 insn_buf
[cnt
++] = BPF_ALU32_IMM(BPF_RSH
,
9955 insn_buf
[cnt
++] = BPF_ALU32_IMM(BPF_AND
, insn
->dst_reg
,
9956 (1 << size
* 8) - 1);
9959 insn_buf
[cnt
++] = BPF_ALU64_IMM(BPF_RSH
,
9962 insn_buf
[cnt
++] = BPF_ALU64_IMM(BPF_AND
, insn
->dst_reg
,
9963 (1ULL << size
* 8) - 1);
9967 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
9973 /* keep walking new program and skip insns we just inserted */
9974 env
->prog
= new_prog
;
9975 insn
= new_prog
->insnsi
+ i
+ delta
;
9981 static int jit_subprogs(struct bpf_verifier_env
*env
)
9983 struct bpf_prog
*prog
= env
->prog
, **func
, *tmp
;
9984 int i
, j
, subprog_start
, subprog_end
= 0, len
, subprog
;
9985 struct bpf_insn
*insn
;
9987 int err
, num_exentries
;
9989 if (env
->subprog_cnt
<= 1)
9992 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
9993 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
9994 insn
->src_reg
!= BPF_PSEUDO_CALL
)
9996 /* Upon error here we cannot fall back to interpreter but
9997 * need a hard reject of the program. Thus -EFAULT is
9998 * propagated in any case.
10000 subprog
= find_subprog(env
, i
+ insn
->imm
+ 1);
10002 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
10003 i
+ insn
->imm
+ 1);
10006 /* temporarily remember subprog id inside insn instead of
10007 * aux_data, since next loop will split up all insns into funcs
10009 insn
->off
= subprog
;
10010 /* remember original imm in case JIT fails and fallback
10011 * to interpreter will be needed
10013 env
->insn_aux_data
[i
].call_imm
= insn
->imm
;
10014 /* point imm to __bpf_call_base+1 from JITs point of view */
10018 err
= bpf_prog_alloc_jited_linfo(prog
);
10020 goto out_undo_insn
;
10023 func
= kcalloc(env
->subprog_cnt
, sizeof(prog
), GFP_KERNEL
);
10025 goto out_undo_insn
;
10027 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
10028 subprog_start
= subprog_end
;
10029 subprog_end
= env
->subprog_info
[i
+ 1].start
;
10031 len
= subprog_end
- subprog_start
;
10032 /* BPF_PROG_RUN doesn't call subprogs directly,
10033 * hence main prog stats include the runtime of subprogs.
10034 * subprogs don't have IDs and not reachable via prog_get_next_id
10035 * func[i]->aux->stats will never be accessed and stays NULL
10037 func
[i
] = bpf_prog_alloc_no_stats(bpf_prog_size(len
), GFP_USER
);
10040 memcpy(func
[i
]->insnsi
, &prog
->insnsi
[subprog_start
],
10041 len
* sizeof(struct bpf_insn
));
10042 func
[i
]->type
= prog
->type
;
10043 func
[i
]->len
= len
;
10044 if (bpf_prog_calc_tag(func
[i
]))
10046 func
[i
]->is_func
= 1;
10047 func
[i
]->aux
->func_idx
= i
;
10048 /* the btf and func_info will be freed only at prog->aux */
10049 func
[i
]->aux
->btf
= prog
->aux
->btf
;
10050 func
[i
]->aux
->func_info
= prog
->aux
->func_info
;
10052 /* Use bpf_prog_F_tag to indicate functions in stack traces.
10053 * Long term would need debug info to populate names
10055 func
[i
]->aux
->name
[0] = 'F';
10056 func
[i
]->aux
->stack_depth
= env
->subprog_info
[i
].stack_depth
;
10057 func
[i
]->jit_requested
= 1;
10058 func
[i
]->aux
->linfo
= prog
->aux
->linfo
;
10059 func
[i
]->aux
->nr_linfo
= prog
->aux
->nr_linfo
;
10060 func
[i
]->aux
->jited_linfo
= prog
->aux
->jited_linfo
;
10061 func
[i
]->aux
->linfo_idx
= env
->subprog_info
[i
].linfo_idx
;
10063 insn
= func
[i
]->insnsi
;
10064 for (j
= 0; j
< func
[i
]->len
; j
++, insn
++) {
10065 if (BPF_CLASS(insn
->code
) == BPF_LDX
&&
10066 BPF_MODE(insn
->code
) == BPF_PROBE_MEM
)
10069 func
[i
]->aux
->num_exentries
= num_exentries
;
10070 func
[i
] = bpf_int_jit_compile(func
[i
]);
10071 if (!func
[i
]->jited
) {
10077 /* at this point all bpf functions were successfully JITed
10078 * now populate all bpf_calls with correct addresses and
10079 * run last pass of JIT
10081 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
10082 insn
= func
[i
]->insnsi
;
10083 for (j
= 0; j
< func
[i
]->len
; j
++, insn
++) {
10084 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
10085 insn
->src_reg
!= BPF_PSEUDO_CALL
)
10087 subprog
= insn
->off
;
10088 insn
->imm
= BPF_CAST_CALL(func
[subprog
]->bpf_func
) -
10092 /* we use the aux data to keep a list of the start addresses
10093 * of the JITed images for each function in the program
10095 * for some architectures, such as powerpc64, the imm field
10096 * might not be large enough to hold the offset of the start
10097 * address of the callee's JITed image from __bpf_call_base
10099 * in such cases, we can lookup the start address of a callee
10100 * by using its subprog id, available from the off field of
10101 * the call instruction, as an index for this list
10103 func
[i
]->aux
->func
= func
;
10104 func
[i
]->aux
->func_cnt
= env
->subprog_cnt
;
10106 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
10107 old_bpf_func
= func
[i
]->bpf_func
;
10108 tmp
= bpf_int_jit_compile(func
[i
]);
10109 if (tmp
!= func
[i
] || func
[i
]->bpf_func
!= old_bpf_func
) {
10110 verbose(env
, "JIT doesn't support bpf-to-bpf calls\n");
10117 /* finally lock prog and jit images for all functions and
10118 * populate kallsysm
10120 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
10121 bpf_prog_lock_ro(func
[i
]);
10122 bpf_prog_kallsyms_add(func
[i
]);
10125 /* Last step: make now unused interpreter insns from main
10126 * prog consistent for later dump requests, so they can
10127 * later look the same as if they were interpreted only.
10129 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
10130 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
10131 insn
->src_reg
!= BPF_PSEUDO_CALL
)
10133 insn
->off
= env
->insn_aux_data
[i
].call_imm
;
10134 subprog
= find_subprog(env
, i
+ insn
->off
+ 1);
10135 insn
->imm
= subprog
;
10139 prog
->bpf_func
= func
[0]->bpf_func
;
10140 prog
->aux
->func
= func
;
10141 prog
->aux
->func_cnt
= env
->subprog_cnt
;
10142 bpf_prog_free_unused_jited_linfo(prog
);
10145 for (i
= 0; i
< env
->subprog_cnt
; i
++)
10147 bpf_jit_free(func
[i
]);
10150 /* cleanup main prog to be interpreted */
10151 prog
->jit_requested
= 0;
10152 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
10153 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
10154 insn
->src_reg
!= BPF_PSEUDO_CALL
)
10157 insn
->imm
= env
->insn_aux_data
[i
].call_imm
;
10159 bpf_prog_free_jited_linfo(prog
);
10163 static int fixup_call_args(struct bpf_verifier_env
*env
)
10165 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
10166 struct bpf_prog
*prog
= env
->prog
;
10167 struct bpf_insn
*insn
= prog
->insnsi
;
10172 if (env
->prog
->jit_requested
&&
10173 !bpf_prog_is_dev_bound(env
->prog
->aux
)) {
10174 err
= jit_subprogs(env
);
10177 if (err
== -EFAULT
)
10180 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
10181 for (i
= 0; i
< prog
->len
; i
++, insn
++) {
10182 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
10183 insn
->src_reg
!= BPF_PSEUDO_CALL
)
10185 depth
= get_callee_stack_depth(env
, insn
, i
);
10188 bpf_patch_call_args(insn
, depth
);
10195 /* fixup insn->imm field of bpf_call instructions
10196 * and inline eligible helpers as explicit sequence of BPF instructions
10198 * this function is called after eBPF program passed verification
10200 static int fixup_bpf_calls(struct bpf_verifier_env
*env
)
10202 struct bpf_prog
*prog
= env
->prog
;
10203 bool expect_blinding
= bpf_jit_blinding_enabled(prog
);
10204 struct bpf_insn
*insn
= prog
->insnsi
;
10205 const struct bpf_func_proto
*fn
;
10206 const int insn_cnt
= prog
->len
;
10207 const struct bpf_map_ops
*ops
;
10208 struct bpf_insn_aux_data
*aux
;
10209 struct bpf_insn insn_buf
[16];
10210 struct bpf_prog
*new_prog
;
10211 struct bpf_map
*map_ptr
;
10212 int i
, ret
, cnt
, delta
= 0;
10214 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
10215 if (insn
->code
== (BPF_ALU64
| BPF_MOD
| BPF_X
) ||
10216 insn
->code
== (BPF_ALU64
| BPF_DIV
| BPF_X
) ||
10217 insn
->code
== (BPF_ALU
| BPF_MOD
| BPF_X
) ||
10218 insn
->code
== (BPF_ALU
| BPF_DIV
| BPF_X
)) {
10219 bool is64
= BPF_CLASS(insn
->code
) == BPF_ALU64
;
10220 struct bpf_insn mask_and_div
[] = {
10221 BPF_MOV32_REG(insn
->src_reg
, insn
->src_reg
),
10222 /* Rx div 0 -> 0 */
10223 BPF_JMP_IMM(BPF_JNE
, insn
->src_reg
, 0, 2),
10224 BPF_ALU32_REG(BPF_XOR
, insn
->dst_reg
, insn
->dst_reg
),
10225 BPF_JMP_IMM(BPF_JA
, 0, 0, 1),
10228 struct bpf_insn mask_and_mod
[] = {
10229 BPF_MOV32_REG(insn
->src_reg
, insn
->src_reg
),
10230 /* Rx mod 0 -> Rx */
10231 BPF_JMP_IMM(BPF_JEQ
, insn
->src_reg
, 0, 1),
10234 struct bpf_insn
*patchlet
;
10236 if (insn
->code
== (BPF_ALU64
| BPF_DIV
| BPF_X
) ||
10237 insn
->code
== (BPF_ALU
| BPF_DIV
| BPF_X
)) {
10238 patchlet
= mask_and_div
+ (is64
? 1 : 0);
10239 cnt
= ARRAY_SIZE(mask_and_div
) - (is64
? 1 : 0);
10241 patchlet
= mask_and_mod
+ (is64
? 1 : 0);
10242 cnt
= ARRAY_SIZE(mask_and_mod
) - (is64
? 1 : 0);
10245 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, patchlet
, cnt
);
10250 env
->prog
= prog
= new_prog
;
10251 insn
= new_prog
->insnsi
+ i
+ delta
;
10255 if (BPF_CLASS(insn
->code
) == BPF_LD
&&
10256 (BPF_MODE(insn
->code
) == BPF_ABS
||
10257 BPF_MODE(insn
->code
) == BPF_IND
)) {
10258 cnt
= env
->ops
->gen_ld_abs(insn
, insn_buf
);
10259 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
)) {
10260 verbose(env
, "bpf verifier is misconfigured\n");
10264 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
10269 env
->prog
= prog
= new_prog
;
10270 insn
= new_prog
->insnsi
+ i
+ delta
;
10274 if (insn
->code
== (BPF_ALU64
| BPF_ADD
| BPF_X
) ||
10275 insn
->code
== (BPF_ALU64
| BPF_SUB
| BPF_X
)) {
10276 const u8 code_add
= BPF_ALU64
| BPF_ADD
| BPF_X
;
10277 const u8 code_sub
= BPF_ALU64
| BPF_SUB
| BPF_X
;
10278 struct bpf_insn insn_buf
[16];
10279 struct bpf_insn
*patch
= &insn_buf
[0];
10283 aux
= &env
->insn_aux_data
[i
+ delta
];
10284 if (!aux
->alu_state
||
10285 aux
->alu_state
== BPF_ALU_NON_POINTER
)
10288 isneg
= aux
->alu_state
& BPF_ALU_NEG_VALUE
;
10289 issrc
= (aux
->alu_state
& BPF_ALU_SANITIZE
) ==
10290 BPF_ALU_SANITIZE_SRC
;
10292 off_reg
= issrc
? insn
->src_reg
: insn
->dst_reg
;
10294 *patch
++ = BPF_ALU64_IMM(BPF_MUL
, off_reg
, -1);
10295 *patch
++ = BPF_MOV32_IMM(BPF_REG_AX
, aux
->alu_limit
- 1);
10296 *patch
++ = BPF_ALU64_REG(BPF_SUB
, BPF_REG_AX
, off_reg
);
10297 *patch
++ = BPF_ALU64_REG(BPF_OR
, BPF_REG_AX
, off_reg
);
10298 *patch
++ = BPF_ALU64_IMM(BPF_NEG
, BPF_REG_AX
, 0);
10299 *patch
++ = BPF_ALU64_IMM(BPF_ARSH
, BPF_REG_AX
, 63);
10301 *patch
++ = BPF_ALU64_REG(BPF_AND
, BPF_REG_AX
,
10303 insn
->src_reg
= BPF_REG_AX
;
10305 *patch
++ = BPF_ALU64_REG(BPF_AND
, off_reg
,
10309 insn
->code
= insn
->code
== code_add
?
10310 code_sub
: code_add
;
10312 if (issrc
&& isneg
)
10313 *patch
++ = BPF_ALU64_IMM(BPF_MUL
, off_reg
, -1);
10314 cnt
= patch
- insn_buf
;
10316 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
10321 env
->prog
= prog
= new_prog
;
10322 insn
= new_prog
->insnsi
+ i
+ delta
;
10326 if (insn
->code
!= (BPF_JMP
| BPF_CALL
))
10328 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
10331 if (insn
->imm
== BPF_FUNC_get_route_realm
)
10332 prog
->dst_needed
= 1;
10333 if (insn
->imm
== BPF_FUNC_get_prandom_u32
)
10334 bpf_user_rnd_init_once();
10335 if (insn
->imm
== BPF_FUNC_override_return
)
10336 prog
->kprobe_override
= 1;
10337 if (insn
->imm
== BPF_FUNC_tail_call
) {
10338 /* If we tail call into other programs, we
10339 * cannot make any assumptions since they can
10340 * be replaced dynamically during runtime in
10341 * the program array.
10343 prog
->cb_access
= 1;
10344 env
->prog
->aux
->stack_depth
= MAX_BPF_STACK
;
10345 env
->prog
->aux
->max_pkt_offset
= MAX_PACKET_OFF
;
10347 /* mark bpf_tail_call as different opcode to avoid
10348 * conditional branch in the interpeter for every normal
10349 * call and to prevent accidental JITing by JIT compiler
10350 * that doesn't support bpf_tail_call yet
10353 insn
->code
= BPF_JMP
| BPF_TAIL_CALL
;
10355 aux
= &env
->insn_aux_data
[i
+ delta
];
10356 if (env
->bpf_capable
&& !expect_blinding
&&
10357 prog
->jit_requested
&&
10358 !bpf_map_key_poisoned(aux
) &&
10359 !bpf_map_ptr_poisoned(aux
) &&
10360 !bpf_map_ptr_unpriv(aux
)) {
10361 struct bpf_jit_poke_descriptor desc
= {
10362 .reason
= BPF_POKE_REASON_TAIL_CALL
,
10363 .tail_call
.map
= BPF_MAP_PTR(aux
->map_ptr_state
),
10364 .tail_call
.key
= bpf_map_key_immediate(aux
),
10367 ret
= bpf_jit_add_poke_descriptor(prog
, &desc
);
10369 verbose(env
, "adding tail call poke descriptor failed\n");
10373 insn
->imm
= ret
+ 1;
10377 if (!bpf_map_ptr_unpriv(aux
))
10380 /* instead of changing every JIT dealing with tail_call
10381 * emit two extra insns:
10382 * if (index >= max_entries) goto out;
10383 * index &= array->index_mask;
10384 * to avoid out-of-bounds cpu speculation
10386 if (bpf_map_ptr_poisoned(aux
)) {
10387 verbose(env
, "tail_call abusing map_ptr\n");
10391 map_ptr
= BPF_MAP_PTR(aux
->map_ptr_state
);
10392 insn_buf
[0] = BPF_JMP_IMM(BPF_JGE
, BPF_REG_3
,
10393 map_ptr
->max_entries
, 2);
10394 insn_buf
[1] = BPF_ALU32_IMM(BPF_AND
, BPF_REG_3
,
10395 container_of(map_ptr
,
10398 insn_buf
[2] = *insn
;
10400 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
10405 env
->prog
= prog
= new_prog
;
10406 insn
= new_prog
->insnsi
+ i
+ delta
;
10410 /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
10411 * and other inlining handlers are currently limited to 64 bit
10414 if (prog
->jit_requested
&& BITS_PER_LONG
== 64 &&
10415 (insn
->imm
== BPF_FUNC_map_lookup_elem
||
10416 insn
->imm
== BPF_FUNC_map_update_elem
||
10417 insn
->imm
== BPF_FUNC_map_delete_elem
||
10418 insn
->imm
== BPF_FUNC_map_push_elem
||
10419 insn
->imm
== BPF_FUNC_map_pop_elem
||
10420 insn
->imm
== BPF_FUNC_map_peek_elem
)) {
10421 aux
= &env
->insn_aux_data
[i
+ delta
];
10422 if (bpf_map_ptr_poisoned(aux
))
10423 goto patch_call_imm
;
10425 map_ptr
= BPF_MAP_PTR(aux
->map_ptr_state
);
10426 ops
= map_ptr
->ops
;
10427 if (insn
->imm
== BPF_FUNC_map_lookup_elem
&&
10428 ops
->map_gen_lookup
) {
10429 cnt
= ops
->map_gen_lookup(map_ptr
, insn_buf
);
10430 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
)) {
10431 verbose(env
, "bpf verifier is misconfigured\n");
10435 new_prog
= bpf_patch_insn_data(env
, i
+ delta
,
10441 env
->prog
= prog
= new_prog
;
10442 insn
= new_prog
->insnsi
+ i
+ delta
;
10446 BUILD_BUG_ON(!__same_type(ops
->map_lookup_elem
,
10447 (void *(*)(struct bpf_map
*map
, void *key
))NULL
));
10448 BUILD_BUG_ON(!__same_type(ops
->map_delete_elem
,
10449 (int (*)(struct bpf_map
*map
, void *key
))NULL
));
10450 BUILD_BUG_ON(!__same_type(ops
->map_update_elem
,
10451 (int (*)(struct bpf_map
*map
, void *key
, void *value
,
10453 BUILD_BUG_ON(!__same_type(ops
->map_push_elem
,
10454 (int (*)(struct bpf_map
*map
, void *value
,
10456 BUILD_BUG_ON(!__same_type(ops
->map_pop_elem
,
10457 (int (*)(struct bpf_map
*map
, void *value
))NULL
));
10458 BUILD_BUG_ON(!__same_type(ops
->map_peek_elem
,
10459 (int (*)(struct bpf_map
*map
, void *value
))NULL
));
10461 switch (insn
->imm
) {
10462 case BPF_FUNC_map_lookup_elem
:
10463 insn
->imm
= BPF_CAST_CALL(ops
->map_lookup_elem
) -
10466 case BPF_FUNC_map_update_elem
:
10467 insn
->imm
= BPF_CAST_CALL(ops
->map_update_elem
) -
10470 case BPF_FUNC_map_delete_elem
:
10471 insn
->imm
= BPF_CAST_CALL(ops
->map_delete_elem
) -
10474 case BPF_FUNC_map_push_elem
:
10475 insn
->imm
= BPF_CAST_CALL(ops
->map_push_elem
) -
10478 case BPF_FUNC_map_pop_elem
:
10479 insn
->imm
= BPF_CAST_CALL(ops
->map_pop_elem
) -
10482 case BPF_FUNC_map_peek_elem
:
10483 insn
->imm
= BPF_CAST_CALL(ops
->map_peek_elem
) -
10488 goto patch_call_imm
;
10491 if (prog
->jit_requested
&& BITS_PER_LONG
== 64 &&
10492 insn
->imm
== BPF_FUNC_jiffies64
) {
10493 struct bpf_insn ld_jiffies_addr
[2] = {
10494 BPF_LD_IMM64(BPF_REG_0
,
10495 (unsigned long)&jiffies
),
10498 insn_buf
[0] = ld_jiffies_addr
[0];
10499 insn_buf
[1] = ld_jiffies_addr
[1];
10500 insn_buf
[2] = BPF_LDX_MEM(BPF_DW
, BPF_REG_0
,
10504 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
,
10510 env
->prog
= prog
= new_prog
;
10511 insn
= new_prog
->insnsi
+ i
+ delta
;
10516 fn
= env
->ops
->get_func_proto(insn
->imm
, env
->prog
);
10517 /* all functions that have prototype and verifier allowed
10518 * programs to call them, must be real in-kernel functions
10522 "kernel subsystem misconfigured func %s#%d\n",
10523 func_id_name(insn
->imm
), insn
->imm
);
10526 insn
->imm
= fn
->func
- __bpf_call_base
;
10529 /* Since poke tab is now finalized, publish aux to tracker. */
10530 for (i
= 0; i
< prog
->aux
->size_poke_tab
; i
++) {
10531 map_ptr
= prog
->aux
->poke_tab
[i
].tail_call
.map
;
10532 if (!map_ptr
->ops
->map_poke_track
||
10533 !map_ptr
->ops
->map_poke_untrack
||
10534 !map_ptr
->ops
->map_poke_run
) {
10535 verbose(env
, "bpf verifier is misconfigured\n");
10539 ret
= map_ptr
->ops
->map_poke_track(map_ptr
, prog
->aux
);
10541 verbose(env
, "tracking tail call prog failed\n");
10549 static void free_states(struct bpf_verifier_env
*env
)
10551 struct bpf_verifier_state_list
*sl
, *sln
;
10554 sl
= env
->free_list
;
10557 free_verifier_state(&sl
->state
, false);
10561 env
->free_list
= NULL
;
10563 if (!env
->explored_states
)
10566 for (i
= 0; i
< state_htab_size(env
); i
++) {
10567 sl
= env
->explored_states
[i
];
10571 free_verifier_state(&sl
->state
, false);
10575 env
->explored_states
[i
] = NULL
;
10579 /* The verifier is using insn_aux_data[] to store temporary data during
10580 * verification and to store information for passes that run after the
10581 * verification like dead code sanitization. do_check_common() for subprogram N
10582 * may analyze many other subprograms. sanitize_insn_aux_data() clears all
10583 * temporary data after do_check_common() finds that subprogram N cannot be
10584 * verified independently. pass_cnt counts the number of times
10585 * do_check_common() was run and insn->aux->seen tells the pass number
10586 * insn_aux_data was touched. These variables are compared to clear temporary
10587 * data from failed pass. For testing and experiments do_check_common() can be
10588 * run multiple times even when prior attempt to verify is unsuccessful.
10590 static void sanitize_insn_aux_data(struct bpf_verifier_env
*env
)
10592 struct bpf_insn
*insn
= env
->prog
->insnsi
;
10593 struct bpf_insn_aux_data
*aux
;
10596 for (i
= 0; i
< env
->prog
->len
; i
++) {
10597 class = BPF_CLASS(insn
[i
].code
);
10598 if (class != BPF_LDX
&& class != BPF_STX
)
10600 aux
= &env
->insn_aux_data
[i
];
10601 if (aux
->seen
!= env
->pass_cnt
)
10603 memset(aux
, 0, offsetof(typeof(*aux
), orig_idx
));
10607 static int do_check_common(struct bpf_verifier_env
*env
, int subprog
)
10609 bool pop_log
= !(env
->log
.level
& BPF_LOG_LEVEL2
);
10610 struct bpf_verifier_state
*state
;
10611 struct bpf_reg_state
*regs
;
10614 env
->prev_linfo
= NULL
;
10617 state
= kzalloc(sizeof(struct bpf_verifier_state
), GFP_KERNEL
);
10620 state
->curframe
= 0;
10621 state
->speculative
= false;
10622 state
->branches
= 1;
10623 state
->frame
[0] = kzalloc(sizeof(struct bpf_func_state
), GFP_KERNEL
);
10624 if (!state
->frame
[0]) {
10628 env
->cur_state
= state
;
10629 init_func_state(env
, state
->frame
[0],
10630 BPF_MAIN_FUNC
/* callsite */,
10634 regs
= state
->frame
[state
->curframe
]->regs
;
10635 if (subprog
|| env
->prog
->type
== BPF_PROG_TYPE_EXT
) {
10636 ret
= btf_prepare_func_args(env
, subprog
, regs
);
10639 for (i
= BPF_REG_1
; i
<= BPF_REG_5
; i
++) {
10640 if (regs
[i
].type
== PTR_TO_CTX
)
10641 mark_reg_known_zero(env
, regs
, i
);
10642 else if (regs
[i
].type
== SCALAR_VALUE
)
10643 mark_reg_unknown(env
, regs
, i
);
10646 /* 1st arg to a function */
10647 regs
[BPF_REG_1
].type
= PTR_TO_CTX
;
10648 mark_reg_known_zero(env
, regs
, BPF_REG_1
);
10649 ret
= btf_check_func_arg_match(env
, subprog
, regs
);
10650 if (ret
== -EFAULT
)
10651 /* unlikely verifier bug. abort.
10652 * ret == 0 and ret < 0 are sadly acceptable for
10653 * main() function due to backward compatibility.
10654 * Like socket filter program may be written as:
10655 * int bpf_prog(struct pt_regs *ctx)
10656 * and never dereference that ctx in the program.
10657 * 'struct pt_regs' is a type mismatch for socket
10658 * filter that should be using 'struct __sk_buff'.
10663 ret
= do_check(env
);
10665 /* check for NULL is necessary, since cur_state can be freed inside
10666 * do_check() under memory pressure.
10668 if (env
->cur_state
) {
10669 free_verifier_state(env
->cur_state
, true);
10670 env
->cur_state
= NULL
;
10672 while (!pop_stack(env
, NULL
, NULL
, false));
10673 if (!ret
&& pop_log
)
10674 bpf_vlog_reset(&env
->log
, 0);
10677 /* clean aux data in case subprog was rejected */
10678 sanitize_insn_aux_data(env
);
10682 /* Verify all global functions in a BPF program one by one based on their BTF.
10683 * All global functions must pass verification. Otherwise the whole program is rejected.
10694 * foo() will be verified first for R1=any_scalar_value. During verification it
10695 * will be assumed that bar() already verified successfully and call to bar()
10696 * from foo() will be checked for type match only. Later bar() will be verified
10697 * independently to check that it's safe for R1=any_scalar_value.
10699 static int do_check_subprogs(struct bpf_verifier_env
*env
)
10701 struct bpf_prog_aux
*aux
= env
->prog
->aux
;
10704 if (!aux
->func_info
)
10707 for (i
= 1; i
< env
->subprog_cnt
; i
++) {
10708 if (aux
->func_info_aux
[i
].linkage
!= BTF_FUNC_GLOBAL
)
10710 env
->insn_idx
= env
->subprog_info
[i
].start
;
10711 WARN_ON_ONCE(env
->insn_idx
== 0);
10712 ret
= do_check_common(env
, i
);
10715 } else if (env
->log
.level
& BPF_LOG_LEVEL
) {
10717 "Func#%d is safe for any args that match its prototype\n",
10724 static int do_check_main(struct bpf_verifier_env
*env
)
10729 ret
= do_check_common(env
, 0);
10731 env
->prog
->aux
->stack_depth
= env
->subprog_info
[0].stack_depth
;
10736 static void print_verification_stats(struct bpf_verifier_env
*env
)
10740 if (env
->log
.level
& BPF_LOG_STATS
) {
10741 verbose(env
, "verification time %lld usec\n",
10742 div_u64(env
->verification_time
, 1000));
10743 verbose(env
, "stack depth ");
10744 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
10745 u32 depth
= env
->subprog_info
[i
].stack_depth
;
10747 verbose(env
, "%d", depth
);
10748 if (i
+ 1 < env
->subprog_cnt
)
10751 verbose(env
, "\n");
10753 verbose(env
, "processed %d insns (limit %d) max_states_per_insn %d "
10754 "total_states %d peak_states %d mark_read %d\n",
10755 env
->insn_processed
, BPF_COMPLEXITY_LIMIT_INSNS
,
10756 env
->max_states_per_insn
, env
->total_states
,
10757 env
->peak_states
, env
->longest_mark_read_walk
);
10760 static int check_struct_ops_btf_id(struct bpf_verifier_env
*env
)
10762 const struct btf_type
*t
, *func_proto
;
10763 const struct bpf_struct_ops
*st_ops
;
10764 const struct btf_member
*member
;
10765 struct bpf_prog
*prog
= env
->prog
;
10766 u32 btf_id
, member_idx
;
10769 btf_id
= prog
->aux
->attach_btf_id
;
10770 st_ops
= bpf_struct_ops_find(btf_id
);
10772 verbose(env
, "attach_btf_id %u is not a supported struct\n",
10778 member_idx
= prog
->expected_attach_type
;
10779 if (member_idx
>= btf_type_vlen(t
)) {
10780 verbose(env
, "attach to invalid member idx %u of struct %s\n",
10781 member_idx
, st_ops
->name
);
10785 member
= &btf_type_member(t
)[member_idx
];
10786 mname
= btf_name_by_offset(btf_vmlinux
, member
->name_off
);
10787 func_proto
= btf_type_resolve_func_ptr(btf_vmlinux
, member
->type
,
10790 verbose(env
, "attach to invalid member %s(@idx %u) of struct %s\n",
10791 mname
, member_idx
, st_ops
->name
);
10795 if (st_ops
->check_member
) {
10796 int err
= st_ops
->check_member(t
, member
);
10799 verbose(env
, "attach to unsupported member %s of struct %s\n",
10800 mname
, st_ops
->name
);
10805 prog
->aux
->attach_func_proto
= func_proto
;
10806 prog
->aux
->attach_func_name
= mname
;
10807 env
->ops
= st_ops
->verifier_ops
;
10811 #define SECURITY_PREFIX "security_"
10813 static int check_attach_modify_return(struct bpf_prog
*prog
, unsigned long addr
)
10815 if (within_error_injection_list(addr
) ||
10816 !strncmp(SECURITY_PREFIX
, prog
->aux
->attach_func_name
,
10817 sizeof(SECURITY_PREFIX
) - 1))
10823 static int check_attach_btf_id(struct bpf_verifier_env
*env
)
10825 struct bpf_prog
*prog
= env
->prog
;
10826 bool prog_extension
= prog
->type
== BPF_PROG_TYPE_EXT
;
10827 struct bpf_prog
*tgt_prog
= prog
->aux
->linked_prog
;
10828 u32 btf_id
= prog
->aux
->attach_btf_id
;
10829 const char prefix
[] = "btf_trace_";
10830 struct btf_func_model fmodel
;
10831 int ret
= 0, subprog
= -1, i
;
10832 struct bpf_trampoline
*tr
;
10833 const struct btf_type
*t
;
10834 bool conservative
= true;
10840 if (prog
->type
== BPF_PROG_TYPE_STRUCT_OPS
)
10841 return check_struct_ops_btf_id(env
);
10843 if (prog
->type
!= BPF_PROG_TYPE_TRACING
&&
10844 prog
->type
!= BPF_PROG_TYPE_LSM
&&
10849 verbose(env
, "Tracing programs must provide btf_id\n");
10852 btf
= bpf_prog_get_target_btf(prog
);
10855 "FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
10858 t
= btf_type_by_id(btf
, btf_id
);
10860 verbose(env
, "attach_btf_id %u is invalid\n", btf_id
);
10863 tname
= btf_name_by_offset(btf
, t
->name_off
);
10865 verbose(env
, "attach_btf_id %u doesn't have a name\n", btf_id
);
10869 struct bpf_prog_aux
*aux
= tgt_prog
->aux
;
10871 for (i
= 0; i
< aux
->func_info_cnt
; i
++)
10872 if (aux
->func_info
[i
].type_id
== btf_id
) {
10876 if (subprog
== -1) {
10877 verbose(env
, "Subprog %s doesn't exist\n", tname
);
10880 conservative
= aux
->func_info_aux
[subprog
].unreliable
;
10881 if (prog_extension
) {
10882 if (conservative
) {
10884 "Cannot replace static functions\n");
10887 if (!prog
->jit_requested
) {
10889 "Extension programs should be JITed\n");
10892 env
->ops
= bpf_verifier_ops
[tgt_prog
->type
];
10893 prog
->expected_attach_type
= tgt_prog
->expected_attach_type
;
10895 if (!tgt_prog
->jited
) {
10896 verbose(env
, "Can attach to only JITed progs\n");
10899 if (tgt_prog
->type
== prog
->type
) {
10900 /* Cannot fentry/fexit another fentry/fexit program.
10901 * Cannot attach program extension to another extension.
10902 * It's ok to attach fentry/fexit to extension program.
10904 verbose(env
, "Cannot recursively attach\n");
10907 if (tgt_prog
->type
== BPF_PROG_TYPE_TRACING
&&
10909 (tgt_prog
->expected_attach_type
== BPF_TRACE_FENTRY
||
10910 tgt_prog
->expected_attach_type
== BPF_TRACE_FEXIT
)) {
10911 /* Program extensions can extend all program types
10912 * except fentry/fexit. The reason is the following.
10913 * The fentry/fexit programs are used for performance
10914 * analysis, stats and can be attached to any program
10915 * type except themselves. When extension program is
10916 * replacing XDP function it is necessary to allow
10917 * performance analysis of all functions. Both original
10918 * XDP program and its program extension. Hence
10919 * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
10920 * allowed. If extending of fentry/fexit was allowed it
10921 * would be possible to create long call chain
10922 * fentry->extension->fentry->extension beyond
10923 * reasonable stack size. Hence extending fentry is not
10926 verbose(env
, "Cannot extend fentry/fexit\n");
10929 key
= ((u64
)aux
->id
) << 32 | btf_id
;
10931 if (prog_extension
) {
10932 verbose(env
, "Cannot replace kernel functions\n");
10938 switch (prog
->expected_attach_type
) {
10939 case BPF_TRACE_RAW_TP
:
10942 "Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
10945 if (!btf_type_is_typedef(t
)) {
10946 verbose(env
, "attach_btf_id %u is not a typedef\n",
10950 if (strncmp(prefix
, tname
, sizeof(prefix
) - 1)) {
10951 verbose(env
, "attach_btf_id %u points to wrong type name %s\n",
10955 tname
+= sizeof(prefix
) - 1;
10956 t
= btf_type_by_id(btf
, t
->type
);
10957 if (!btf_type_is_ptr(t
))
10958 /* should never happen in valid vmlinux build */
10960 t
= btf_type_by_id(btf
, t
->type
);
10961 if (!btf_type_is_func_proto(t
))
10962 /* should never happen in valid vmlinux build */
10965 /* remember two read only pointers that are valid for
10966 * the life time of the kernel
10968 prog
->aux
->attach_func_name
= tname
;
10969 prog
->aux
->attach_func_proto
= t
;
10970 prog
->aux
->attach_btf_trace
= true;
10972 case BPF_TRACE_ITER
:
10973 if (!btf_type_is_func(t
)) {
10974 verbose(env
, "attach_btf_id %u is not a function\n",
10978 t
= btf_type_by_id(btf
, t
->type
);
10979 if (!btf_type_is_func_proto(t
))
10981 prog
->aux
->attach_func_name
= tname
;
10982 prog
->aux
->attach_func_proto
= t
;
10983 if (!bpf_iter_prog_supported(prog
))
10985 ret
= btf_distill_func_proto(&env
->log
, btf
, t
,
10989 if (!prog_extension
)
10992 case BPF_MODIFY_RETURN
:
10994 case BPF_TRACE_FENTRY
:
10995 case BPF_TRACE_FEXIT
:
10996 prog
->aux
->attach_func_name
= tname
;
10997 if (prog
->type
== BPF_PROG_TYPE_LSM
) {
10998 ret
= bpf_lsm_verify_prog(&env
->log
, prog
);
11003 if (!btf_type_is_func(t
)) {
11004 verbose(env
, "attach_btf_id %u is not a function\n",
11008 if (prog_extension
&&
11009 btf_check_type_match(env
, prog
, btf
, t
))
11011 t
= btf_type_by_id(btf
, t
->type
);
11012 if (!btf_type_is_func_proto(t
))
11014 tr
= bpf_trampoline_lookup(key
);
11017 /* t is either vmlinux type or another program's type */
11018 prog
->aux
->attach_func_proto
= t
;
11019 mutex_lock(&tr
->mutex
);
11020 if (tr
->func
.addr
) {
11021 prog
->aux
->trampoline
= tr
;
11024 if (tgt_prog
&& conservative
) {
11025 prog
->aux
->attach_func_proto
= NULL
;
11028 ret
= btf_distill_func_proto(&env
->log
, btf
, t
,
11029 tname
, &tr
->func
.model
);
11034 addr
= (long) tgt_prog
->bpf_func
;
11036 addr
= (long) tgt_prog
->aux
->func
[subprog
]->bpf_func
;
11038 addr
= kallsyms_lookup_name(tname
);
11041 "The address of function %s cannot be found\n",
11048 if (prog
->expected_attach_type
== BPF_MODIFY_RETURN
) {
11049 ret
= check_attach_modify_return(prog
, addr
);
11051 verbose(env
, "%s() is not modifiable\n",
11052 prog
->aux
->attach_func_name
);
11057 tr
->func
.addr
= (void *)addr
;
11058 prog
->aux
->trampoline
= tr
;
11060 mutex_unlock(&tr
->mutex
);
11062 bpf_trampoline_put(tr
);
11067 int bpf_check(struct bpf_prog
**prog
, union bpf_attr
*attr
,
11068 union bpf_attr __user
*uattr
)
11070 u64 start_time
= ktime_get_ns();
11071 struct bpf_verifier_env
*env
;
11072 struct bpf_verifier_log
*log
;
11073 int i
, len
, ret
= -EINVAL
;
11076 /* no program is valid */
11077 if (ARRAY_SIZE(bpf_verifier_ops
) == 0)
11080 /* 'struct bpf_verifier_env' can be global, but since it's not small,
11081 * allocate/free it every time bpf_check() is called
11083 env
= kzalloc(sizeof(struct bpf_verifier_env
), GFP_KERNEL
);
11088 len
= (*prog
)->len
;
11089 env
->insn_aux_data
=
11090 vzalloc(array_size(sizeof(struct bpf_insn_aux_data
), len
));
11092 if (!env
->insn_aux_data
)
11094 for (i
= 0; i
< len
; i
++)
11095 env
->insn_aux_data
[i
].orig_idx
= i
;
11097 env
->ops
= bpf_verifier_ops
[env
->prog
->type
];
11098 is_priv
= bpf_capable();
11100 if (!btf_vmlinux
&& IS_ENABLED(CONFIG_DEBUG_INFO_BTF
)) {
11101 mutex_lock(&bpf_verifier_lock
);
11103 btf_vmlinux
= btf_parse_vmlinux();
11104 mutex_unlock(&bpf_verifier_lock
);
11107 /* grab the mutex to protect few globals used by verifier */
11109 mutex_lock(&bpf_verifier_lock
);
11111 if (attr
->log_level
|| attr
->log_buf
|| attr
->log_size
) {
11112 /* user requested verbose verifier output
11113 * and supplied buffer to store the verification trace
11115 log
->level
= attr
->log_level
;
11116 log
->ubuf
= (char __user
*) (unsigned long) attr
->log_buf
;
11117 log
->len_total
= attr
->log_size
;
11120 /* log attributes have to be sane */
11121 if (log
->len_total
< 128 || log
->len_total
> UINT_MAX
>> 2 ||
11122 !log
->level
|| !log
->ubuf
|| log
->level
& ~BPF_LOG_MASK
)
11126 if (IS_ERR(btf_vmlinux
)) {
11127 /* Either gcc or pahole or kernel are broken. */
11128 verbose(env
, "in-kernel BTF is malformed\n");
11129 ret
= PTR_ERR(btf_vmlinux
);
11130 goto skip_full_check
;
11133 env
->strict_alignment
= !!(attr
->prog_flags
& BPF_F_STRICT_ALIGNMENT
);
11134 if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
))
11135 env
->strict_alignment
= true;
11136 if (attr
->prog_flags
& BPF_F_ANY_ALIGNMENT
)
11137 env
->strict_alignment
= false;
11139 env
->allow_ptr_leaks
= bpf_allow_ptr_leaks();
11140 env
->allow_ptr_to_map_access
= bpf_allow_ptr_to_map_access();
11141 env
->bypass_spec_v1
= bpf_bypass_spec_v1();
11142 env
->bypass_spec_v4
= bpf_bypass_spec_v4();
11143 env
->bpf_capable
= bpf_capable();
11146 env
->test_state_freq
= attr
->prog_flags
& BPF_F_TEST_STATE_FREQ
;
11148 ret
= replace_map_fd_with_map_ptr(env
);
11150 goto skip_full_check
;
11152 if (bpf_prog_is_dev_bound(env
->prog
->aux
)) {
11153 ret
= bpf_prog_offload_verifier_prep(env
->prog
);
11155 goto skip_full_check
;
11158 env
->explored_states
= kvcalloc(state_htab_size(env
),
11159 sizeof(struct bpf_verifier_state_list
*),
11162 if (!env
->explored_states
)
11163 goto skip_full_check
;
11165 ret
= check_subprogs(env
);
11167 goto skip_full_check
;
11169 ret
= check_btf_info(env
, attr
, uattr
);
11171 goto skip_full_check
;
11173 ret
= check_attach_btf_id(env
);
11175 goto skip_full_check
;
11177 ret
= check_cfg(env
);
11179 goto skip_full_check
;
11181 ret
= do_check_subprogs(env
);
11182 ret
= ret
?: do_check_main(env
);
11184 if (ret
== 0 && bpf_prog_is_dev_bound(env
->prog
->aux
))
11185 ret
= bpf_prog_offload_finalize(env
);
11188 kvfree(env
->explored_states
);
11191 ret
= check_max_stack_depth(env
);
11193 /* instruction rewrites happen after this point */
11196 opt_hard_wire_dead_code_branches(env
);
11198 ret
= opt_remove_dead_code(env
);
11200 ret
= opt_remove_nops(env
);
11203 sanitize_dead_code(env
);
11207 /* program is valid, convert *(u32*)(ctx + off) accesses */
11208 ret
= convert_ctx_accesses(env
);
11211 ret
= fixup_bpf_calls(env
);
11213 /* do 32-bit optimization after insn patching has done so those patched
11214 * insns could be handled correctly.
11216 if (ret
== 0 && !bpf_prog_is_dev_bound(env
->prog
->aux
)) {
11217 ret
= opt_subreg_zext_lo32_rnd_hi32(env
, attr
);
11218 env
->prog
->aux
->verifier_zext
= bpf_jit_needs_zext() ? !ret
11223 ret
= fixup_call_args(env
);
11225 env
->verification_time
= ktime_get_ns() - start_time
;
11226 print_verification_stats(env
);
11228 if (log
->level
&& bpf_verifier_log_full(log
))
11230 if (log
->level
&& !log
->ubuf
) {
11232 goto err_release_maps
;
11235 if (ret
== 0 && env
->used_map_cnt
) {
11236 /* if program passed verifier, update used_maps in bpf_prog_info */
11237 env
->prog
->aux
->used_maps
= kmalloc_array(env
->used_map_cnt
,
11238 sizeof(env
->used_maps
[0]),
11241 if (!env
->prog
->aux
->used_maps
) {
11243 goto err_release_maps
;
11246 memcpy(env
->prog
->aux
->used_maps
, env
->used_maps
,
11247 sizeof(env
->used_maps
[0]) * env
->used_map_cnt
);
11248 env
->prog
->aux
->used_map_cnt
= env
->used_map_cnt
;
11250 /* program is valid. Convert pseudo bpf_ld_imm64 into generic
11251 * bpf_ld_imm64 instructions
11253 convert_pseudo_ld_imm64(env
);
11257 adjust_btf_func(env
);
11260 if (!env
->prog
->aux
->used_maps
)
11261 /* if we didn't copy map pointers into bpf_prog_info, release
11262 * them now. Otherwise free_used_maps() will release them.
11266 /* extension progs temporarily inherit the attach_type of their targets
11267 for verification purposes, so set it back to zero before returning
11269 if (env
->prog
->type
== BPF_PROG_TYPE_EXT
)
11270 env
->prog
->expected_attach_type
= 0;
11275 mutex_unlock(&bpf_verifier_lock
);
11276 vfree(env
->insn_aux_data
);