1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
2 * Copyright (c) 2016 Facebook
3 * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 #include <uapi/linux/btf.h>
15 #include <linux/kernel.h>
16 #include <linux/types.h>
17 #include <linux/slab.h>
18 #include <linux/bpf.h>
19 #include <linux/btf.h>
20 #include <linux/bpf_verifier.h>
21 #include <linux/filter.h>
22 #include <net/netlink.h>
23 #include <linux/file.h>
24 #include <linux/vmalloc.h>
25 #include <linux/stringify.h>
26 #include <linux/bsearch.h>
27 #include <linux/sort.h>
28 #include <linux/perf_event.h>
29 #include <linux/ctype.h>
33 static const struct bpf_verifier_ops
* const bpf_verifier_ops
[] = {
34 #define BPF_PROG_TYPE(_id, _name) \
35 [_id] = & _name ## _verifier_ops,
36 #define BPF_MAP_TYPE(_id, _ops)
37 #include <linux/bpf_types.h>
42 /* bpf_check() is a static code analyzer that walks eBPF program
43 * instruction by instruction and updates register/stack state.
44 * All paths of conditional branches are analyzed until 'bpf_exit' insn.
46 * The first pass is depth-first-search to check that the program is a DAG.
47 * It rejects the following programs:
48 * - larger than BPF_MAXINSNS insns
49 * - if loop is present (detected via back-edge)
50 * - unreachable insns exist (shouldn't be a forest. program = one function)
51 * - out of bounds or malformed jumps
52 * The second pass is all possible path descent from the 1st insn.
53 * Since it's analyzing all pathes through the program, the length of the
54 * analysis is limited to 64k insn, which may be hit even if total number of
55 * insn is less then 4K, but there are too many branches that change stack/regs.
56 * Number of 'branches to be analyzed' is limited to 1k
58 * On entry to each instruction, each register has a type, and the instruction
59 * changes the types of the registers depending on instruction semantics.
60 * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
63 * All registers are 64-bit.
64 * R0 - return register
65 * R1-R5 argument passing registers
66 * R6-R9 callee saved registers
67 * R10 - frame pointer read-only
69 * At the start of BPF program the register R1 contains a pointer to bpf_context
70 * and has type PTR_TO_CTX.
72 * Verifier tracks arithmetic operations on pointers in case:
73 * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
74 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
75 * 1st insn copies R10 (which has FRAME_PTR) type into R1
76 * and 2nd arithmetic instruction is pattern matched to recognize
77 * that it wants to construct a pointer to some element within stack.
78 * So after 2nd insn, the register R1 has type PTR_TO_STACK
79 * (and -20 constant is saved for further stack bounds checking).
80 * Meaning that this reg is a pointer to stack plus known immediate constant.
82 * Most of the time the registers have SCALAR_VALUE type, which
83 * means the register has some value, but it's not a valid pointer.
84 * (like pointer plus pointer becomes SCALAR_VALUE type)
86 * When verifier sees load or store instructions the type of base register
87 * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
88 * four pointer types recognized by check_mem_access() function.
90 * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
91 * and the range of [ptr, ptr + map's value_size) is accessible.
93 * registers used to pass values to function calls are checked against
94 * function argument constraints.
96 * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
97 * It means that the register type passed to this function must be
98 * PTR_TO_STACK and it will be used inside the function as
99 * 'pointer to map element key'
101 * For example the argument constraints for bpf_map_lookup_elem():
102 * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
103 * .arg1_type = ARG_CONST_MAP_PTR,
104 * .arg2_type = ARG_PTR_TO_MAP_KEY,
106 * ret_type says that this function returns 'pointer to map elem value or null'
107 * function expects 1st argument to be a const pointer to 'struct bpf_map' and
108 * 2nd argument should be a pointer to stack, which will be used inside
109 * the helper function as a pointer to map element key.
111 * On the kernel side the helper function looks like:
112 * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
114 * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
115 * void *key = (void *) (unsigned long) r2;
118 * here kernel can access 'key' and 'map' pointers safely, knowing that
119 * [key, key + map->key_size) bytes are valid and were initialized on
120 * the stack of eBPF program.
123 * Corresponding eBPF program may look like:
124 * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR
125 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
126 * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP
127 * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
128 * here verifier looks at prototype of map_lookup_elem() and sees:
129 * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
130 * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
132 * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
133 * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
134 * and were initialized prior to this call.
135 * If it's ok, then verifier allows this BPF_CALL insn and looks at
136 * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
137 * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
138 * returns ether pointer to map value or NULL.
140 * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
141 * insn, the register holding that pointer in the true branch changes state to
142 * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
143 * branch. See check_cond_jmp_op().
145 * After the call R0 is set to return type of the function and registers R1-R5
146 * are set to NOT_INIT to indicate that they are no longer readable.
148 * The following reference types represent a potential reference to a kernel
149 * resource which, after first being allocated, must be checked and freed by
151 * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
153 * When the verifier sees a helper call return a reference type, it allocates a
154 * pointer id for the reference and stores it in the current function state.
155 * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
156 * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
157 * passes through a NULL-check conditional. For the branch wherein the state is
158 * changed to CONST_IMM, the verifier releases the reference.
160 * For each helper function that allocates a reference, such as
161 * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
162 * bpf_sk_release(). When a reference type passes into the release function,
163 * the verifier also releases the reference. If any unchecked or unreleased
164 * reference remains at the end of the program, the verifier rejects it.
167 /* verifier_state + insn_idx are pushed to stack when branch is encountered */
168 struct bpf_verifier_stack_elem
{
169 /* verifer state is 'st'
170 * before processing instruction 'insn_idx'
171 * and after processing instruction 'prev_insn_idx'
173 struct bpf_verifier_state st
;
176 struct bpf_verifier_stack_elem
*next
;
179 #define BPF_COMPLEXITY_LIMIT_STACK 1024
180 #define BPF_COMPLEXITY_LIMIT_STATES 64
182 #define BPF_MAP_PTR_UNPRIV 1UL
183 #define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \
184 POISON_POINTER_DELTA))
185 #define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
187 static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data
*aux
)
189 return BPF_MAP_PTR(aux
->map_state
) == BPF_MAP_PTR_POISON
;
192 static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data
*aux
)
194 return aux
->map_state
& BPF_MAP_PTR_UNPRIV
;
197 static void bpf_map_ptr_store(struct bpf_insn_aux_data
*aux
,
198 const struct bpf_map
*map
, bool unpriv
)
200 BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON
& BPF_MAP_PTR_UNPRIV
);
201 unpriv
|= bpf_map_ptr_unpriv(aux
);
202 aux
->map_state
= (unsigned long)map
|
203 (unpriv
? BPF_MAP_PTR_UNPRIV
: 0UL);
206 struct bpf_call_arg_meta
{
207 struct bpf_map
*map_ptr
;
212 s64 msize_smax_value
;
213 u64 msize_umax_value
;
218 static DEFINE_MUTEX(bpf_verifier_lock
);
220 static const struct bpf_line_info
*
221 find_linfo(const struct bpf_verifier_env
*env
, u32 insn_off
)
223 const struct bpf_line_info
*linfo
;
224 const struct bpf_prog
*prog
;
228 nr_linfo
= prog
->aux
->nr_linfo
;
230 if (!nr_linfo
|| insn_off
>= prog
->len
)
233 linfo
= prog
->aux
->linfo
;
234 for (i
= 1; i
< nr_linfo
; i
++)
235 if (insn_off
< linfo
[i
].insn_off
)
238 return &linfo
[i
- 1];
241 void bpf_verifier_vlog(struct bpf_verifier_log
*log
, const char *fmt
,
246 n
= vscnprintf(log
->kbuf
, BPF_VERIFIER_TMP_LOG_SIZE
, fmt
, args
);
248 WARN_ONCE(n
>= BPF_VERIFIER_TMP_LOG_SIZE
- 1,
249 "verifier log line truncated - local buffer too short\n");
251 n
= min(log
->len_total
- log
->len_used
- 1, n
);
254 if (!copy_to_user(log
->ubuf
+ log
->len_used
, log
->kbuf
, n
+ 1))
260 /* log_level controls verbosity level of eBPF verifier.
261 * bpf_verifier_log_write() is used to dump the verification trace to the log,
262 * so the user can figure out what's wrong with the program
264 __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env
*env
,
265 const char *fmt
, ...)
269 if (!bpf_verifier_log_needed(&env
->log
))
273 bpf_verifier_vlog(&env
->log
, fmt
, args
);
276 EXPORT_SYMBOL_GPL(bpf_verifier_log_write
);
278 __printf(2, 3) static void verbose(void *private_data
, const char *fmt
, ...)
280 struct bpf_verifier_env
*env
= private_data
;
283 if (!bpf_verifier_log_needed(&env
->log
))
287 bpf_verifier_vlog(&env
->log
, fmt
, args
);
291 static const char *ltrim(const char *s
)
299 __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env
*env
,
301 const char *prefix_fmt
, ...)
303 const struct bpf_line_info
*linfo
;
305 if (!bpf_verifier_log_needed(&env
->log
))
308 linfo
= find_linfo(env
, insn_off
);
309 if (!linfo
|| linfo
== env
->prev_linfo
)
315 va_start(args
, prefix_fmt
);
316 bpf_verifier_vlog(&env
->log
, prefix_fmt
, args
);
321 ltrim(btf_name_by_offset(env
->prog
->aux
->btf
,
324 env
->prev_linfo
= linfo
;
327 static bool type_is_pkt_pointer(enum bpf_reg_type type
)
329 return type
== PTR_TO_PACKET
||
330 type
== PTR_TO_PACKET_META
;
333 static bool type_is_sk_pointer(enum bpf_reg_type type
)
335 return type
== PTR_TO_SOCKET
||
336 type
== PTR_TO_SOCK_COMMON
||
337 type
== PTR_TO_TCP_SOCK
;
340 static bool reg_type_may_be_null(enum bpf_reg_type type
)
342 return type
== PTR_TO_MAP_VALUE_OR_NULL
||
343 type
== PTR_TO_SOCKET_OR_NULL
||
344 type
== PTR_TO_SOCK_COMMON_OR_NULL
||
345 type
== PTR_TO_TCP_SOCK_OR_NULL
;
348 static bool reg_may_point_to_spin_lock(const struct bpf_reg_state
*reg
)
350 return reg
->type
== PTR_TO_MAP_VALUE
&&
351 map_value_has_spin_lock(reg
->map_ptr
);
354 static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type
)
356 return type
== PTR_TO_SOCKET
||
357 type
== PTR_TO_SOCKET_OR_NULL
||
358 type
== PTR_TO_TCP_SOCK
||
359 type
== PTR_TO_TCP_SOCK_OR_NULL
;
362 static bool arg_type_may_be_refcounted(enum bpf_arg_type type
)
364 return type
== ARG_PTR_TO_SOCK_COMMON
;
367 /* Determine whether the function releases some resources allocated by another
368 * function call. The first reference type argument will be assumed to be
369 * released by release_reference().
371 static bool is_release_function(enum bpf_func_id func_id
)
373 return func_id
== BPF_FUNC_sk_release
;
376 static bool is_acquire_function(enum bpf_func_id func_id
)
378 return func_id
== BPF_FUNC_sk_lookup_tcp
||
379 func_id
== BPF_FUNC_sk_lookup_udp
||
380 func_id
== BPF_FUNC_skc_lookup_tcp
;
383 static bool is_ptr_cast_function(enum bpf_func_id func_id
)
385 return func_id
== BPF_FUNC_tcp_sock
||
386 func_id
== BPF_FUNC_sk_fullsock
;
389 /* string representation of 'enum bpf_reg_type' */
390 static const char * const reg_type_str
[] = {
392 [SCALAR_VALUE
] = "inv",
393 [PTR_TO_CTX
] = "ctx",
394 [CONST_PTR_TO_MAP
] = "map_ptr",
395 [PTR_TO_MAP_VALUE
] = "map_value",
396 [PTR_TO_MAP_VALUE_OR_NULL
] = "map_value_or_null",
397 [PTR_TO_STACK
] = "fp",
398 [PTR_TO_PACKET
] = "pkt",
399 [PTR_TO_PACKET_META
] = "pkt_meta",
400 [PTR_TO_PACKET_END
] = "pkt_end",
401 [PTR_TO_FLOW_KEYS
] = "flow_keys",
402 [PTR_TO_SOCKET
] = "sock",
403 [PTR_TO_SOCKET_OR_NULL
] = "sock_or_null",
404 [PTR_TO_SOCK_COMMON
] = "sock_common",
405 [PTR_TO_SOCK_COMMON_OR_NULL
] = "sock_common_or_null",
406 [PTR_TO_TCP_SOCK
] = "tcp_sock",
407 [PTR_TO_TCP_SOCK_OR_NULL
] = "tcp_sock_or_null",
408 [PTR_TO_TP_BUFFER
] = "tp_buffer",
411 static char slot_type_char
[] = {
412 [STACK_INVALID
] = '?',
418 static void print_liveness(struct bpf_verifier_env
*env
,
419 enum bpf_reg_liveness live
)
421 if (live
& (REG_LIVE_READ
| REG_LIVE_WRITTEN
| REG_LIVE_DONE
))
423 if (live
& REG_LIVE_READ
)
425 if (live
& REG_LIVE_WRITTEN
)
427 if (live
& REG_LIVE_DONE
)
431 static struct bpf_func_state
*func(struct bpf_verifier_env
*env
,
432 const struct bpf_reg_state
*reg
)
434 struct bpf_verifier_state
*cur
= env
->cur_state
;
436 return cur
->frame
[reg
->frameno
];
439 static void print_verifier_state(struct bpf_verifier_env
*env
,
440 const struct bpf_func_state
*state
)
442 const struct bpf_reg_state
*reg
;
447 verbose(env
, " frame%d:", state
->frameno
);
448 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
449 reg
= &state
->regs
[i
];
453 verbose(env
, " R%d", i
);
454 print_liveness(env
, reg
->live
);
455 verbose(env
, "=%s", reg_type_str
[t
]);
456 if ((t
== SCALAR_VALUE
|| t
== PTR_TO_STACK
) &&
457 tnum_is_const(reg
->var_off
)) {
458 /* reg->off should be 0 for SCALAR_VALUE */
459 verbose(env
, "%lld", reg
->var_off
.value
+ reg
->off
);
460 if (t
== PTR_TO_STACK
)
461 verbose(env
, ",call_%d", func(env
, reg
)->callsite
);
463 verbose(env
, "(id=%d", reg
->id
);
464 if (reg_type_may_be_refcounted_or_null(t
))
465 verbose(env
, ",ref_obj_id=%d", reg
->ref_obj_id
);
466 if (t
!= SCALAR_VALUE
)
467 verbose(env
, ",off=%d", reg
->off
);
468 if (type_is_pkt_pointer(t
))
469 verbose(env
, ",r=%d", reg
->range
);
470 else if (t
== CONST_PTR_TO_MAP
||
471 t
== PTR_TO_MAP_VALUE
||
472 t
== PTR_TO_MAP_VALUE_OR_NULL
)
473 verbose(env
, ",ks=%d,vs=%d",
474 reg
->map_ptr
->key_size
,
475 reg
->map_ptr
->value_size
);
476 if (tnum_is_const(reg
->var_off
)) {
477 /* Typically an immediate SCALAR_VALUE, but
478 * could be a pointer whose offset is too big
481 verbose(env
, ",imm=%llx", reg
->var_off
.value
);
483 if (reg
->smin_value
!= reg
->umin_value
&&
484 reg
->smin_value
!= S64_MIN
)
485 verbose(env
, ",smin_value=%lld",
486 (long long)reg
->smin_value
);
487 if (reg
->smax_value
!= reg
->umax_value
&&
488 reg
->smax_value
!= S64_MAX
)
489 verbose(env
, ",smax_value=%lld",
490 (long long)reg
->smax_value
);
491 if (reg
->umin_value
!= 0)
492 verbose(env
, ",umin_value=%llu",
493 (unsigned long long)reg
->umin_value
);
494 if (reg
->umax_value
!= U64_MAX
)
495 verbose(env
, ",umax_value=%llu",
496 (unsigned long long)reg
->umax_value
);
497 if (!tnum_is_unknown(reg
->var_off
)) {
500 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
501 verbose(env
, ",var_off=%s", tn_buf
);
507 for (i
= 0; i
< state
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
508 char types_buf
[BPF_REG_SIZE
+ 1];
512 for (j
= 0; j
< BPF_REG_SIZE
; j
++) {
513 if (state
->stack
[i
].slot_type
[j
] != STACK_INVALID
)
515 types_buf
[j
] = slot_type_char
[
516 state
->stack
[i
].slot_type
[j
]];
518 types_buf
[BPF_REG_SIZE
] = 0;
521 verbose(env
, " fp%d", (-i
- 1) * BPF_REG_SIZE
);
522 print_liveness(env
, state
->stack
[i
].spilled_ptr
.live
);
523 if (state
->stack
[i
].slot_type
[0] == STACK_SPILL
)
525 reg_type_str
[state
->stack
[i
].spilled_ptr
.type
]);
527 verbose(env
, "=%s", types_buf
);
529 if (state
->acquired_refs
&& state
->refs
[0].id
) {
530 verbose(env
, " refs=%d", state
->refs
[0].id
);
531 for (i
= 1; i
< state
->acquired_refs
; i
++)
532 if (state
->refs
[i
].id
)
533 verbose(env
, ",%d", state
->refs
[i
].id
);
538 #define COPY_STATE_FN(NAME, COUNT, FIELD, SIZE) \
539 static int copy_##NAME##_state(struct bpf_func_state *dst, \
540 const struct bpf_func_state *src) \
544 if (WARN_ON_ONCE(dst->COUNT < src->COUNT)) { \
545 /* internal bug, make state invalid to reject the program */ \
546 memset(dst, 0, sizeof(*dst)); \
549 memcpy(dst->FIELD, src->FIELD, \
550 sizeof(*src->FIELD) * (src->COUNT / SIZE)); \
553 /* copy_reference_state() */
554 COPY_STATE_FN(reference
, acquired_refs
, refs
, 1)
555 /* copy_stack_state() */
556 COPY_STATE_FN(stack
, allocated_stack
, stack
, BPF_REG_SIZE
)
559 #define REALLOC_STATE_FN(NAME, COUNT, FIELD, SIZE) \
560 static int realloc_##NAME##_state(struct bpf_func_state *state, int size, \
563 u32 old_size = state->COUNT; \
564 struct bpf_##NAME##_state *new_##FIELD; \
565 int slot = size / SIZE; \
567 if (size <= old_size || !size) { \
570 state->COUNT = slot * SIZE; \
571 if (!size && old_size) { \
572 kfree(state->FIELD); \
573 state->FIELD = NULL; \
577 new_##FIELD = kmalloc_array(slot, sizeof(struct bpf_##NAME##_state), \
583 memcpy(new_##FIELD, state->FIELD, \
584 sizeof(*new_##FIELD) * (old_size / SIZE)); \
585 memset(new_##FIELD + old_size / SIZE, 0, \
586 sizeof(*new_##FIELD) * (size - old_size) / SIZE); \
588 state->COUNT = slot * SIZE; \
589 kfree(state->FIELD); \
590 state->FIELD = new_##FIELD; \
593 /* realloc_reference_state() */
594 REALLOC_STATE_FN(reference
, acquired_refs
, refs
, 1)
595 /* realloc_stack_state() */
596 REALLOC_STATE_FN(stack
, allocated_stack
, stack
, BPF_REG_SIZE
)
597 #undef REALLOC_STATE_FN
599 /* do_check() starts with zero-sized stack in struct bpf_verifier_state to
600 * make it consume minimal amount of memory. check_stack_write() access from
601 * the program calls into realloc_func_state() to grow the stack size.
602 * Note there is a non-zero 'parent' pointer inside bpf_verifier_state
603 * which realloc_stack_state() copies over. It points to previous
604 * bpf_verifier_state which is never reallocated.
606 static int realloc_func_state(struct bpf_func_state
*state
, int stack_size
,
607 int refs_size
, bool copy_old
)
609 int err
= realloc_reference_state(state
, refs_size
, copy_old
);
612 return realloc_stack_state(state
, stack_size
, copy_old
);
615 /* Acquire a pointer id from the env and update the state->refs to include
616 * this new pointer reference.
617 * On success, returns a valid pointer id to associate with the register
618 * On failure, returns a negative errno.
620 static int acquire_reference_state(struct bpf_verifier_env
*env
, int insn_idx
)
622 struct bpf_func_state
*state
= cur_func(env
);
623 int new_ofs
= state
->acquired_refs
;
626 err
= realloc_reference_state(state
, state
->acquired_refs
+ 1, true);
630 state
->refs
[new_ofs
].id
= id
;
631 state
->refs
[new_ofs
].insn_idx
= insn_idx
;
636 /* release function corresponding to acquire_reference_state(). Idempotent. */
637 static int release_reference_state(struct bpf_func_state
*state
, int ptr_id
)
641 last_idx
= state
->acquired_refs
- 1;
642 for (i
= 0; i
< state
->acquired_refs
; i
++) {
643 if (state
->refs
[i
].id
== ptr_id
) {
644 if (last_idx
&& i
!= last_idx
)
645 memcpy(&state
->refs
[i
], &state
->refs
[last_idx
],
646 sizeof(*state
->refs
));
647 memset(&state
->refs
[last_idx
], 0, sizeof(*state
->refs
));
648 state
->acquired_refs
--;
655 static int transfer_reference_state(struct bpf_func_state
*dst
,
656 struct bpf_func_state
*src
)
658 int err
= realloc_reference_state(dst
, src
->acquired_refs
, false);
661 err
= copy_reference_state(dst
, src
);
667 static void free_func_state(struct bpf_func_state
*state
)
676 static void free_verifier_state(struct bpf_verifier_state
*state
,
681 for (i
= 0; i
<= state
->curframe
; i
++) {
682 free_func_state(state
->frame
[i
]);
683 state
->frame
[i
] = NULL
;
689 /* copy verifier state from src to dst growing dst stack space
690 * when necessary to accommodate larger src stack
692 static int copy_func_state(struct bpf_func_state
*dst
,
693 const struct bpf_func_state
*src
)
697 err
= realloc_func_state(dst
, src
->allocated_stack
, src
->acquired_refs
,
701 memcpy(dst
, src
, offsetof(struct bpf_func_state
, acquired_refs
));
702 err
= copy_reference_state(dst
, src
);
705 return copy_stack_state(dst
, src
);
708 static int copy_verifier_state(struct bpf_verifier_state
*dst_state
,
709 const struct bpf_verifier_state
*src
)
711 struct bpf_func_state
*dst
;
714 /* if dst has more stack frames then src frame, free them */
715 for (i
= src
->curframe
+ 1; i
<= dst_state
->curframe
; i
++) {
716 free_func_state(dst_state
->frame
[i
]);
717 dst_state
->frame
[i
] = NULL
;
719 dst_state
->speculative
= src
->speculative
;
720 dst_state
->curframe
= src
->curframe
;
721 dst_state
->active_spin_lock
= src
->active_spin_lock
;
722 for (i
= 0; i
<= src
->curframe
; i
++) {
723 dst
= dst_state
->frame
[i
];
725 dst
= kzalloc(sizeof(*dst
), GFP_KERNEL
);
728 dst_state
->frame
[i
] = dst
;
730 err
= copy_func_state(dst
, src
->frame
[i
]);
737 static int pop_stack(struct bpf_verifier_env
*env
, int *prev_insn_idx
,
740 struct bpf_verifier_state
*cur
= env
->cur_state
;
741 struct bpf_verifier_stack_elem
*elem
, *head
= env
->head
;
744 if (env
->head
== NULL
)
748 err
= copy_verifier_state(cur
, &head
->st
);
753 *insn_idx
= head
->insn_idx
;
755 *prev_insn_idx
= head
->prev_insn_idx
;
757 free_verifier_state(&head
->st
, false);
764 static struct bpf_verifier_state
*push_stack(struct bpf_verifier_env
*env
,
765 int insn_idx
, int prev_insn_idx
,
768 struct bpf_verifier_state
*cur
= env
->cur_state
;
769 struct bpf_verifier_stack_elem
*elem
;
772 elem
= kzalloc(sizeof(struct bpf_verifier_stack_elem
), GFP_KERNEL
);
776 elem
->insn_idx
= insn_idx
;
777 elem
->prev_insn_idx
= prev_insn_idx
;
778 elem
->next
= env
->head
;
781 err
= copy_verifier_state(&elem
->st
, cur
);
784 elem
->st
.speculative
|= speculative
;
785 if (env
->stack_size
> BPF_COMPLEXITY_LIMIT_STACK
) {
786 verbose(env
, "BPF program is too complex\n");
791 free_verifier_state(env
->cur_state
, true);
792 env
->cur_state
= NULL
;
793 /* pop all elements and return */
794 while (!pop_stack(env
, NULL
, NULL
));
798 #define CALLER_SAVED_REGS 6
799 static const int caller_saved
[CALLER_SAVED_REGS
] = {
800 BPF_REG_0
, BPF_REG_1
, BPF_REG_2
, BPF_REG_3
, BPF_REG_4
, BPF_REG_5
803 static void __mark_reg_not_init(struct bpf_reg_state
*reg
);
805 /* Mark the unknown part of a register (variable offset or scalar value) as
806 * known to have the value @imm.
808 static void __mark_reg_known(struct bpf_reg_state
*reg
, u64 imm
)
810 /* Clear id, off, and union(map_ptr, range) */
811 memset(((u8
*)reg
) + sizeof(reg
->type
), 0,
812 offsetof(struct bpf_reg_state
, var_off
) - sizeof(reg
->type
));
813 reg
->var_off
= tnum_const(imm
);
814 reg
->smin_value
= (s64
)imm
;
815 reg
->smax_value
= (s64
)imm
;
816 reg
->umin_value
= imm
;
817 reg
->umax_value
= imm
;
820 /* Mark the 'variable offset' part of a register as zero. This should be
821 * used only on registers holding a pointer type.
823 static void __mark_reg_known_zero(struct bpf_reg_state
*reg
)
825 __mark_reg_known(reg
, 0);
828 static void __mark_reg_const_zero(struct bpf_reg_state
*reg
)
830 __mark_reg_known(reg
, 0);
831 reg
->type
= SCALAR_VALUE
;
834 static void mark_reg_known_zero(struct bpf_verifier_env
*env
,
835 struct bpf_reg_state
*regs
, u32 regno
)
837 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
838 verbose(env
, "mark_reg_known_zero(regs, %u)\n", regno
);
839 /* Something bad happened, let's kill all regs */
840 for (regno
= 0; regno
< MAX_BPF_REG
; regno
++)
841 __mark_reg_not_init(regs
+ regno
);
844 __mark_reg_known_zero(regs
+ regno
);
847 static bool reg_is_pkt_pointer(const struct bpf_reg_state
*reg
)
849 return type_is_pkt_pointer(reg
->type
);
852 static bool reg_is_pkt_pointer_any(const struct bpf_reg_state
*reg
)
854 return reg_is_pkt_pointer(reg
) ||
855 reg
->type
== PTR_TO_PACKET_END
;
858 /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
859 static bool reg_is_init_pkt_pointer(const struct bpf_reg_state
*reg
,
860 enum bpf_reg_type which
)
862 /* The register can already have a range from prior markings.
863 * This is fine as long as it hasn't been advanced from its
866 return reg
->type
== which
&&
869 tnum_equals_const(reg
->var_off
, 0);
872 /* Attempts to improve min/max values based on var_off information */
873 static void __update_reg_bounds(struct bpf_reg_state
*reg
)
875 /* min signed is max(sign bit) | min(other bits) */
876 reg
->smin_value
= max_t(s64
, reg
->smin_value
,
877 reg
->var_off
.value
| (reg
->var_off
.mask
& S64_MIN
));
878 /* max signed is min(sign bit) | max(other bits) */
879 reg
->smax_value
= min_t(s64
, reg
->smax_value
,
880 reg
->var_off
.value
| (reg
->var_off
.mask
& S64_MAX
));
881 reg
->umin_value
= max(reg
->umin_value
, reg
->var_off
.value
);
882 reg
->umax_value
= min(reg
->umax_value
,
883 reg
->var_off
.value
| reg
->var_off
.mask
);
886 /* Uses signed min/max values to inform unsigned, and vice-versa */
887 static void __reg_deduce_bounds(struct bpf_reg_state
*reg
)
889 /* Learn sign from signed bounds.
890 * If we cannot cross the sign boundary, then signed and unsigned bounds
891 * are the same, so combine. This works even in the negative case, e.g.
892 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
894 if (reg
->smin_value
>= 0 || reg
->smax_value
< 0) {
895 reg
->smin_value
= reg
->umin_value
= max_t(u64
, reg
->smin_value
,
897 reg
->smax_value
= reg
->umax_value
= min_t(u64
, reg
->smax_value
,
901 /* Learn sign from unsigned bounds. Signed bounds cross the sign
902 * boundary, so we must be careful.
904 if ((s64
)reg
->umax_value
>= 0) {
905 /* Positive. We can't learn anything from the smin, but smax
906 * is positive, hence safe.
908 reg
->smin_value
= reg
->umin_value
;
909 reg
->smax_value
= reg
->umax_value
= min_t(u64
, reg
->smax_value
,
911 } else if ((s64
)reg
->umin_value
< 0) {
912 /* Negative. We can't learn anything from the smax, but smin
913 * is negative, hence safe.
915 reg
->smin_value
= reg
->umin_value
= max_t(u64
, reg
->smin_value
,
917 reg
->smax_value
= reg
->umax_value
;
921 /* Attempts to improve var_off based on unsigned min/max information */
922 static void __reg_bound_offset(struct bpf_reg_state
*reg
)
924 reg
->var_off
= tnum_intersect(reg
->var_off
,
925 tnum_range(reg
->umin_value
,
929 /* Reset the min/max bounds of a register */
930 static void __mark_reg_unbounded(struct bpf_reg_state
*reg
)
932 reg
->smin_value
= S64_MIN
;
933 reg
->smax_value
= S64_MAX
;
935 reg
->umax_value
= U64_MAX
;
938 /* Mark a register as having a completely unknown (scalar) value. */
939 static void __mark_reg_unknown(struct bpf_reg_state
*reg
)
942 * Clear type, id, off, and union(map_ptr, range) and
943 * padding between 'type' and union
945 memset(reg
, 0, offsetof(struct bpf_reg_state
, var_off
));
946 reg
->type
= SCALAR_VALUE
;
947 reg
->var_off
= tnum_unknown
;
949 __mark_reg_unbounded(reg
);
952 static void mark_reg_unknown(struct bpf_verifier_env
*env
,
953 struct bpf_reg_state
*regs
, u32 regno
)
955 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
956 verbose(env
, "mark_reg_unknown(regs, %u)\n", regno
);
957 /* Something bad happened, let's kill all regs except FP */
958 for (regno
= 0; regno
< BPF_REG_FP
; regno
++)
959 __mark_reg_not_init(regs
+ regno
);
962 __mark_reg_unknown(regs
+ regno
);
965 static void __mark_reg_not_init(struct bpf_reg_state
*reg
)
967 __mark_reg_unknown(reg
);
968 reg
->type
= NOT_INIT
;
971 static void mark_reg_not_init(struct bpf_verifier_env
*env
,
972 struct bpf_reg_state
*regs
, u32 regno
)
974 if (WARN_ON(regno
>= MAX_BPF_REG
)) {
975 verbose(env
, "mark_reg_not_init(regs, %u)\n", regno
);
976 /* Something bad happened, let's kill all regs except FP */
977 for (regno
= 0; regno
< BPF_REG_FP
; regno
++)
978 __mark_reg_not_init(regs
+ regno
);
981 __mark_reg_not_init(regs
+ regno
);
984 static void init_reg_state(struct bpf_verifier_env
*env
,
985 struct bpf_func_state
*state
)
987 struct bpf_reg_state
*regs
= state
->regs
;
990 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
991 mark_reg_not_init(env
, regs
, i
);
992 regs
[i
].live
= REG_LIVE_NONE
;
993 regs
[i
].parent
= NULL
;
997 regs
[BPF_REG_FP
].type
= PTR_TO_STACK
;
998 mark_reg_known_zero(env
, regs
, BPF_REG_FP
);
999 regs
[BPF_REG_FP
].frameno
= state
->frameno
;
1001 /* 1st arg to a function */
1002 regs
[BPF_REG_1
].type
= PTR_TO_CTX
;
1003 mark_reg_known_zero(env
, regs
, BPF_REG_1
);
1006 #define BPF_MAIN_FUNC (-1)
1007 static void init_func_state(struct bpf_verifier_env
*env
,
1008 struct bpf_func_state
*state
,
1009 int callsite
, int frameno
, int subprogno
)
1011 state
->callsite
= callsite
;
1012 state
->frameno
= frameno
;
1013 state
->subprogno
= subprogno
;
1014 init_reg_state(env
, state
);
1018 SRC_OP
, /* register is used as source operand */
1019 DST_OP
, /* register is used as destination operand */
1020 DST_OP_NO_MARK
/* same as above, check only, don't mark */
1023 static int cmp_subprogs(const void *a
, const void *b
)
1025 return ((struct bpf_subprog_info
*)a
)->start
-
1026 ((struct bpf_subprog_info
*)b
)->start
;
1029 static int find_subprog(struct bpf_verifier_env
*env
, int off
)
1031 struct bpf_subprog_info
*p
;
1033 p
= bsearch(&off
, env
->subprog_info
, env
->subprog_cnt
,
1034 sizeof(env
->subprog_info
[0]), cmp_subprogs
);
1037 return p
- env
->subprog_info
;
1041 static int add_subprog(struct bpf_verifier_env
*env
, int off
)
1043 int insn_cnt
= env
->prog
->len
;
1046 if (off
>= insn_cnt
|| off
< 0) {
1047 verbose(env
, "call to invalid destination\n");
1050 ret
= find_subprog(env
, off
);
1053 if (env
->subprog_cnt
>= BPF_MAX_SUBPROGS
) {
1054 verbose(env
, "too many subprograms\n");
1057 env
->subprog_info
[env
->subprog_cnt
++].start
= off
;
1058 sort(env
->subprog_info
, env
->subprog_cnt
,
1059 sizeof(env
->subprog_info
[0]), cmp_subprogs
, NULL
);
1063 static int check_subprogs(struct bpf_verifier_env
*env
)
1065 int i
, ret
, subprog_start
, subprog_end
, off
, cur_subprog
= 0;
1066 struct bpf_subprog_info
*subprog
= env
->subprog_info
;
1067 struct bpf_insn
*insn
= env
->prog
->insnsi
;
1068 int insn_cnt
= env
->prog
->len
;
1070 /* Add entry function. */
1071 ret
= add_subprog(env
, 0);
1075 /* determine subprog starts. The end is one before the next starts */
1076 for (i
= 0; i
< insn_cnt
; i
++) {
1077 if (insn
[i
].code
!= (BPF_JMP
| BPF_CALL
))
1079 if (insn
[i
].src_reg
!= BPF_PSEUDO_CALL
)
1081 if (!env
->allow_ptr_leaks
) {
1082 verbose(env
, "function calls to other bpf functions are allowed for root only\n");
1085 ret
= add_subprog(env
, i
+ insn
[i
].imm
+ 1);
1090 /* Add a fake 'exit' subprog which could simplify subprog iteration
1091 * logic. 'subprog_cnt' should not be increased.
1093 subprog
[env
->subprog_cnt
].start
= insn_cnt
;
1095 if (env
->log
.level
& BPF_LOG_LEVEL2
)
1096 for (i
= 0; i
< env
->subprog_cnt
; i
++)
1097 verbose(env
, "func#%d @%d\n", i
, subprog
[i
].start
);
1099 /* now check that all jumps are within the same subprog */
1100 subprog_start
= subprog
[cur_subprog
].start
;
1101 subprog_end
= subprog
[cur_subprog
+ 1].start
;
1102 for (i
= 0; i
< insn_cnt
; i
++) {
1103 u8 code
= insn
[i
].code
;
1105 if (BPF_CLASS(code
) != BPF_JMP
&& BPF_CLASS(code
) != BPF_JMP32
)
1107 if (BPF_OP(code
) == BPF_EXIT
|| BPF_OP(code
) == BPF_CALL
)
1109 off
= i
+ insn
[i
].off
+ 1;
1110 if (off
< subprog_start
|| off
>= subprog_end
) {
1111 verbose(env
, "jump out of range from insn %d to %d\n", i
, off
);
1115 if (i
== subprog_end
- 1) {
1116 /* to avoid fall-through from one subprog into another
1117 * the last insn of the subprog should be either exit
1118 * or unconditional jump back
1120 if (code
!= (BPF_JMP
| BPF_EXIT
) &&
1121 code
!= (BPF_JMP
| BPF_JA
)) {
1122 verbose(env
, "last insn is not an exit or jmp\n");
1125 subprog_start
= subprog_end
;
1127 if (cur_subprog
< env
->subprog_cnt
)
1128 subprog_end
= subprog
[cur_subprog
+ 1].start
;
1134 /* Parentage chain of this register (or stack slot) should take care of all
1135 * issues like callee-saved registers, stack slot allocation time, etc.
1137 static int mark_reg_read(struct bpf_verifier_env
*env
,
1138 const struct bpf_reg_state
*state
,
1139 struct bpf_reg_state
*parent
)
1141 bool writes
= parent
== state
->parent
; /* Observe write marks */
1145 /* if read wasn't screened by an earlier write ... */
1146 if (writes
&& state
->live
& REG_LIVE_WRITTEN
)
1148 if (parent
->live
& REG_LIVE_DONE
) {
1149 verbose(env
, "verifier BUG type %s var_off %lld off %d\n",
1150 reg_type_str
[parent
->type
],
1151 parent
->var_off
.value
, parent
->off
);
1154 if (parent
->live
& REG_LIVE_READ
)
1155 /* The parentage chain never changes and
1156 * this parent was already marked as LIVE_READ.
1157 * There is no need to keep walking the chain again and
1158 * keep re-marking all parents as LIVE_READ.
1159 * This case happens when the same register is read
1160 * multiple times without writes into it in-between.
1163 /* ... then we depend on parent's value */
1164 parent
->live
|= REG_LIVE_READ
;
1166 parent
= state
->parent
;
1171 if (env
->longest_mark_read_walk
< cnt
)
1172 env
->longest_mark_read_walk
= cnt
;
1176 static int check_reg_arg(struct bpf_verifier_env
*env
, u32 regno
,
1177 enum reg_arg_type t
)
1179 struct bpf_verifier_state
*vstate
= env
->cur_state
;
1180 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
1181 struct bpf_reg_state
*reg
, *regs
= state
->regs
;
1183 if (regno
>= MAX_BPF_REG
) {
1184 verbose(env
, "R%d is invalid\n", regno
);
1190 /* check whether register used as source operand can be read */
1191 if (reg
->type
== NOT_INIT
) {
1192 verbose(env
, "R%d !read_ok\n", regno
);
1195 /* We don't need to worry about FP liveness because it's read-only */
1196 if (regno
== BPF_REG_FP
)
1199 return mark_reg_read(env
, reg
, reg
->parent
);
1201 /* check whether register used as dest operand can be written to */
1202 if (regno
== BPF_REG_FP
) {
1203 verbose(env
, "frame pointer is read only\n");
1206 reg
->live
|= REG_LIVE_WRITTEN
;
1208 mark_reg_unknown(env
, regs
, regno
);
1213 static bool is_spillable_regtype(enum bpf_reg_type type
)
1216 case PTR_TO_MAP_VALUE
:
1217 case PTR_TO_MAP_VALUE_OR_NULL
:
1221 case PTR_TO_PACKET_META
:
1222 case PTR_TO_PACKET_END
:
1223 case PTR_TO_FLOW_KEYS
:
1224 case CONST_PTR_TO_MAP
:
1226 case PTR_TO_SOCKET_OR_NULL
:
1227 case PTR_TO_SOCK_COMMON
:
1228 case PTR_TO_SOCK_COMMON_OR_NULL
:
1229 case PTR_TO_TCP_SOCK
:
1230 case PTR_TO_TCP_SOCK_OR_NULL
:
1237 /* Does this register contain a constant zero? */
1238 static bool register_is_null(struct bpf_reg_state
*reg
)
1240 return reg
->type
== SCALAR_VALUE
&& tnum_equals_const(reg
->var_off
, 0);
1243 /* check_stack_read/write functions track spill/fill of registers,
1244 * stack boundary and alignment are checked in check_mem_access()
1246 static int check_stack_write(struct bpf_verifier_env
*env
,
1247 struct bpf_func_state
*state
, /* func where register points to */
1248 int off
, int size
, int value_regno
, int insn_idx
)
1250 struct bpf_func_state
*cur
; /* state of the current function */
1251 int i
, slot
= -off
- 1, spi
= slot
/ BPF_REG_SIZE
, err
;
1252 enum bpf_reg_type type
;
1254 err
= realloc_func_state(state
, round_up(slot
+ 1, BPF_REG_SIZE
),
1255 state
->acquired_refs
, true);
1258 /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
1259 * so it's aligned access and [off, off + size) are within stack limits
1261 if (!env
->allow_ptr_leaks
&&
1262 state
->stack
[spi
].slot_type
[0] == STACK_SPILL
&&
1263 size
!= BPF_REG_SIZE
) {
1264 verbose(env
, "attempt to corrupt spilled pointer on stack\n");
1268 cur
= env
->cur_state
->frame
[env
->cur_state
->curframe
];
1269 if (value_regno
>= 0 &&
1270 is_spillable_regtype((type
= cur
->regs
[value_regno
].type
))) {
1272 /* register containing pointer is being spilled into stack */
1273 if (size
!= BPF_REG_SIZE
) {
1274 verbose(env
, "invalid size of register spill\n");
1278 if (state
!= cur
&& type
== PTR_TO_STACK
) {
1279 verbose(env
, "cannot spill pointers to stack into stack frame of the caller\n");
1283 /* save register state */
1284 state
->stack
[spi
].spilled_ptr
= cur
->regs
[value_regno
];
1285 state
->stack
[spi
].spilled_ptr
.live
|= REG_LIVE_WRITTEN
;
1287 for (i
= 0; i
< BPF_REG_SIZE
; i
++) {
1288 if (state
->stack
[spi
].slot_type
[i
] == STACK_MISC
&&
1289 !env
->allow_ptr_leaks
) {
1290 int *poff
= &env
->insn_aux_data
[insn_idx
].sanitize_stack_off
;
1291 int soff
= (-spi
- 1) * BPF_REG_SIZE
;
1293 /* detected reuse of integer stack slot with a pointer
1294 * which means either llvm is reusing stack slot or
1295 * an attacker is trying to exploit CVE-2018-3639
1296 * (speculative store bypass)
1297 * Have to sanitize that slot with preemptive
1300 if (*poff
&& *poff
!= soff
) {
1301 /* disallow programs where single insn stores
1302 * into two different stack slots, since verifier
1303 * cannot sanitize them
1306 "insn %d cannot access two stack slots fp%d and fp%d",
1307 insn_idx
, *poff
, soff
);
1312 state
->stack
[spi
].slot_type
[i
] = STACK_SPILL
;
1315 u8 type
= STACK_MISC
;
1317 /* regular write of data into stack destroys any spilled ptr */
1318 state
->stack
[spi
].spilled_ptr
.type
= NOT_INIT
;
1319 /* Mark slots as STACK_MISC if they belonged to spilled ptr. */
1320 if (state
->stack
[spi
].slot_type
[0] == STACK_SPILL
)
1321 for (i
= 0; i
< BPF_REG_SIZE
; i
++)
1322 state
->stack
[spi
].slot_type
[i
] = STACK_MISC
;
1324 /* only mark the slot as written if all 8 bytes were written
1325 * otherwise read propagation may incorrectly stop too soon
1326 * when stack slots are partially written.
1327 * This heuristic means that read propagation will be
1328 * conservative, since it will add reg_live_read marks
1329 * to stack slots all the way to first state when programs
1330 * writes+reads less than 8 bytes
1332 if (size
== BPF_REG_SIZE
)
1333 state
->stack
[spi
].spilled_ptr
.live
|= REG_LIVE_WRITTEN
;
1335 /* when we zero initialize stack slots mark them as such */
1336 if (value_regno
>= 0 &&
1337 register_is_null(&cur
->regs
[value_regno
]))
1340 /* Mark slots affected by this stack write. */
1341 for (i
= 0; i
< size
; i
++)
1342 state
->stack
[spi
].slot_type
[(slot
- i
) % BPF_REG_SIZE
] =
1348 static int check_stack_read(struct bpf_verifier_env
*env
,
1349 struct bpf_func_state
*reg_state
/* func where register points to */,
1350 int off
, int size
, int value_regno
)
1352 struct bpf_verifier_state
*vstate
= env
->cur_state
;
1353 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
1354 int i
, slot
= -off
- 1, spi
= slot
/ BPF_REG_SIZE
;
1357 if (reg_state
->allocated_stack
<= slot
) {
1358 verbose(env
, "invalid read from stack off %d+0 size %d\n",
1362 stype
= reg_state
->stack
[spi
].slot_type
;
1364 if (stype
[0] == STACK_SPILL
) {
1365 if (size
!= BPF_REG_SIZE
) {
1366 verbose(env
, "invalid size of register spill\n");
1369 for (i
= 1; i
< BPF_REG_SIZE
; i
++) {
1370 if (stype
[(slot
- i
) % BPF_REG_SIZE
] != STACK_SPILL
) {
1371 verbose(env
, "corrupted spill memory\n");
1376 if (value_regno
>= 0) {
1377 /* restore register state from stack */
1378 state
->regs
[value_regno
] = reg_state
->stack
[spi
].spilled_ptr
;
1379 /* mark reg as written since spilled pointer state likely
1380 * has its liveness marks cleared by is_state_visited()
1381 * which resets stack/reg liveness for state transitions
1383 state
->regs
[value_regno
].live
|= REG_LIVE_WRITTEN
;
1385 mark_reg_read(env
, ®_state
->stack
[spi
].spilled_ptr
,
1386 reg_state
->stack
[spi
].spilled_ptr
.parent
);
1391 for (i
= 0; i
< size
; i
++) {
1392 if (stype
[(slot
- i
) % BPF_REG_SIZE
] == STACK_MISC
)
1394 if (stype
[(slot
- i
) % BPF_REG_SIZE
] == STACK_ZERO
) {
1398 verbose(env
, "invalid read from stack off %d+%d size %d\n",
1402 mark_reg_read(env
, ®_state
->stack
[spi
].spilled_ptr
,
1403 reg_state
->stack
[spi
].spilled_ptr
.parent
);
1404 if (value_regno
>= 0) {
1405 if (zeros
== size
) {
1406 /* any size read into register is zero extended,
1407 * so the whole register == const_zero
1409 __mark_reg_const_zero(&state
->regs
[value_regno
]);
1411 /* have read misc data from the stack */
1412 mark_reg_unknown(env
, state
->regs
, value_regno
);
1414 state
->regs
[value_regno
].live
|= REG_LIVE_WRITTEN
;
1420 static int check_stack_access(struct bpf_verifier_env
*env
,
1421 const struct bpf_reg_state
*reg
,
1424 /* Stack accesses must be at a fixed offset, so that we
1425 * can determine what type of data were returned. See
1426 * check_stack_read().
1428 if (!tnum_is_const(reg
->var_off
)) {
1431 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
1432 verbose(env
, "variable stack access var_off=%s off=%d size=%d\n",
1437 if (off
>= 0 || off
< -MAX_BPF_STACK
) {
1438 verbose(env
, "invalid stack off=%d size=%d\n", off
, size
);
1445 static int check_map_access_type(struct bpf_verifier_env
*env
, u32 regno
,
1446 int off
, int size
, enum bpf_access_type type
)
1448 struct bpf_reg_state
*regs
= cur_regs(env
);
1449 struct bpf_map
*map
= regs
[regno
].map_ptr
;
1450 u32 cap
= bpf_map_flags_to_cap(map
);
1452 if (type
== BPF_WRITE
&& !(cap
& BPF_MAP_CAN_WRITE
)) {
1453 verbose(env
, "write into map forbidden, value_size=%d off=%d size=%d\n",
1454 map
->value_size
, off
, size
);
1458 if (type
== BPF_READ
&& !(cap
& BPF_MAP_CAN_READ
)) {
1459 verbose(env
, "read from map forbidden, value_size=%d off=%d size=%d\n",
1460 map
->value_size
, off
, size
);
1467 /* check read/write into map element returned by bpf_map_lookup_elem() */
1468 static int __check_map_access(struct bpf_verifier_env
*env
, u32 regno
, int off
,
1469 int size
, bool zero_size_allowed
)
1471 struct bpf_reg_state
*regs
= cur_regs(env
);
1472 struct bpf_map
*map
= regs
[regno
].map_ptr
;
1474 if (off
< 0 || size
< 0 || (size
== 0 && !zero_size_allowed
) ||
1475 off
+ size
> map
->value_size
) {
1476 verbose(env
, "invalid access to map value, value_size=%d off=%d size=%d\n",
1477 map
->value_size
, off
, size
);
1483 /* check read/write into a map element with possible variable offset */
1484 static int check_map_access(struct bpf_verifier_env
*env
, u32 regno
,
1485 int off
, int size
, bool zero_size_allowed
)
1487 struct bpf_verifier_state
*vstate
= env
->cur_state
;
1488 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
1489 struct bpf_reg_state
*reg
= &state
->regs
[regno
];
1492 /* We may have adjusted the register to this map value, so we
1493 * need to try adding each of min_value and max_value to off
1494 * to make sure our theoretical access will be safe.
1496 if (env
->log
.level
& BPF_LOG_LEVEL
)
1497 print_verifier_state(env
, state
);
1499 /* The minimum value is only important with signed
1500 * comparisons where we can't assume the floor of a
1501 * value is 0. If we are using signed variables for our
1502 * index'es we need to make sure that whatever we use
1503 * will have a set floor within our range.
1505 if (reg
->smin_value
< 0 &&
1506 (reg
->smin_value
== S64_MIN
||
1507 (off
+ reg
->smin_value
!= (s64
)(s32
)(off
+ reg
->smin_value
)) ||
1508 reg
->smin_value
+ off
< 0)) {
1509 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
1513 err
= __check_map_access(env
, regno
, reg
->smin_value
+ off
, size
,
1516 verbose(env
, "R%d min value is outside of the array range\n",
1521 /* If we haven't set a max value then we need to bail since we can't be
1522 * sure we won't do bad things.
1523 * If reg->umax_value + off could overflow, treat that as unbounded too.
1525 if (reg
->umax_value
>= BPF_MAX_VAR_OFF
) {
1526 verbose(env
, "R%d unbounded memory access, make sure to bounds check any array access into a map\n",
1530 err
= __check_map_access(env
, regno
, reg
->umax_value
+ off
, size
,
1533 verbose(env
, "R%d max value is outside of the array range\n",
1536 if (map_value_has_spin_lock(reg
->map_ptr
)) {
1537 u32 lock
= reg
->map_ptr
->spin_lock_off
;
1539 /* if any part of struct bpf_spin_lock can be touched by
1540 * load/store reject this program.
1541 * To check that [x1, x2) overlaps with [y1, y2)
1542 * it is sufficient to check x1 < y2 && y1 < x2.
1544 if (reg
->smin_value
+ off
< lock
+ sizeof(struct bpf_spin_lock
) &&
1545 lock
< reg
->umax_value
+ off
+ size
) {
1546 verbose(env
, "bpf_spin_lock cannot be accessed directly by load/store\n");
1553 #define MAX_PACKET_OFF 0xffff
1555 static bool may_access_direct_pkt_data(struct bpf_verifier_env
*env
,
1556 const struct bpf_call_arg_meta
*meta
,
1557 enum bpf_access_type t
)
1559 switch (env
->prog
->type
) {
1560 /* Program types only with direct read access go here! */
1561 case BPF_PROG_TYPE_LWT_IN
:
1562 case BPF_PROG_TYPE_LWT_OUT
:
1563 case BPF_PROG_TYPE_LWT_SEG6LOCAL
:
1564 case BPF_PROG_TYPE_SK_REUSEPORT
:
1565 case BPF_PROG_TYPE_FLOW_DISSECTOR
:
1566 case BPF_PROG_TYPE_CGROUP_SKB
:
1571 /* Program types with direct read + write access go here! */
1572 case BPF_PROG_TYPE_SCHED_CLS
:
1573 case BPF_PROG_TYPE_SCHED_ACT
:
1574 case BPF_PROG_TYPE_XDP
:
1575 case BPF_PROG_TYPE_LWT_XMIT
:
1576 case BPF_PROG_TYPE_SK_SKB
:
1577 case BPF_PROG_TYPE_SK_MSG
:
1579 return meta
->pkt_access
;
1581 env
->seen_direct_write
= true;
1588 static int __check_packet_access(struct bpf_verifier_env
*env
, u32 regno
,
1589 int off
, int size
, bool zero_size_allowed
)
1591 struct bpf_reg_state
*regs
= cur_regs(env
);
1592 struct bpf_reg_state
*reg
= ®s
[regno
];
1594 if (off
< 0 || size
< 0 || (size
== 0 && !zero_size_allowed
) ||
1595 (u64
)off
+ size
> reg
->range
) {
1596 verbose(env
, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
1597 off
, size
, regno
, reg
->id
, reg
->off
, reg
->range
);
1603 static int check_packet_access(struct bpf_verifier_env
*env
, u32 regno
, int off
,
1604 int size
, bool zero_size_allowed
)
1606 struct bpf_reg_state
*regs
= cur_regs(env
);
1607 struct bpf_reg_state
*reg
= ®s
[regno
];
1610 /* We may have added a variable offset to the packet pointer; but any
1611 * reg->range we have comes after that. We are only checking the fixed
1615 /* We don't allow negative numbers, because we aren't tracking enough
1616 * detail to prove they're safe.
1618 if (reg
->smin_value
< 0) {
1619 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
1623 err
= __check_packet_access(env
, regno
, off
, size
, zero_size_allowed
);
1625 verbose(env
, "R%d offset is outside of the packet\n", regno
);
1629 /* __check_packet_access has made sure "off + size - 1" is within u16.
1630 * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
1631 * otherwise find_good_pkt_pointers would have refused to set range info
1632 * that __check_packet_access would have rejected this pkt access.
1633 * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
1635 env
->prog
->aux
->max_pkt_offset
=
1636 max_t(u32
, env
->prog
->aux
->max_pkt_offset
,
1637 off
+ reg
->umax_value
+ size
- 1);
1642 /* check access to 'struct bpf_context' fields. Supports fixed offsets only */
1643 static int check_ctx_access(struct bpf_verifier_env
*env
, int insn_idx
, int off
, int size
,
1644 enum bpf_access_type t
, enum bpf_reg_type
*reg_type
)
1646 struct bpf_insn_access_aux info
= {
1647 .reg_type
= *reg_type
,
1650 if (env
->ops
->is_valid_access
&&
1651 env
->ops
->is_valid_access(off
, size
, t
, env
->prog
, &info
)) {
1652 /* A non zero info.ctx_field_size indicates that this field is a
1653 * candidate for later verifier transformation to load the whole
1654 * field and then apply a mask when accessed with a narrower
1655 * access than actual ctx access size. A zero info.ctx_field_size
1656 * will only allow for whole field access and rejects any other
1657 * type of narrower access.
1659 *reg_type
= info
.reg_type
;
1661 env
->insn_aux_data
[insn_idx
].ctx_field_size
= info
.ctx_field_size
;
1662 /* remember the offset of last byte accessed in ctx */
1663 if (env
->prog
->aux
->max_ctx_offset
< off
+ size
)
1664 env
->prog
->aux
->max_ctx_offset
= off
+ size
;
1668 verbose(env
, "invalid bpf_context access off=%d size=%d\n", off
, size
);
1672 static int check_flow_keys_access(struct bpf_verifier_env
*env
, int off
,
1675 if (size
< 0 || off
< 0 ||
1676 (u64
)off
+ size
> sizeof(struct bpf_flow_keys
)) {
1677 verbose(env
, "invalid access to flow keys off=%d size=%d\n",
1684 static int check_sock_access(struct bpf_verifier_env
*env
, int insn_idx
,
1685 u32 regno
, int off
, int size
,
1686 enum bpf_access_type t
)
1688 struct bpf_reg_state
*regs
= cur_regs(env
);
1689 struct bpf_reg_state
*reg
= ®s
[regno
];
1690 struct bpf_insn_access_aux info
= {};
1693 if (reg
->smin_value
< 0) {
1694 verbose(env
, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
1699 switch (reg
->type
) {
1700 case PTR_TO_SOCK_COMMON
:
1701 valid
= bpf_sock_common_is_valid_access(off
, size
, t
, &info
);
1704 valid
= bpf_sock_is_valid_access(off
, size
, t
, &info
);
1706 case PTR_TO_TCP_SOCK
:
1707 valid
= bpf_tcp_sock_is_valid_access(off
, size
, t
, &info
);
1715 env
->insn_aux_data
[insn_idx
].ctx_field_size
=
1716 info
.ctx_field_size
;
1720 verbose(env
, "R%d invalid %s access off=%d size=%d\n",
1721 regno
, reg_type_str
[reg
->type
], off
, size
);
1726 static bool __is_pointer_value(bool allow_ptr_leaks
,
1727 const struct bpf_reg_state
*reg
)
1729 if (allow_ptr_leaks
)
1732 return reg
->type
!= SCALAR_VALUE
;
1735 static struct bpf_reg_state
*reg_state(struct bpf_verifier_env
*env
, int regno
)
1737 return cur_regs(env
) + regno
;
1740 static bool is_pointer_value(struct bpf_verifier_env
*env
, int regno
)
1742 return __is_pointer_value(env
->allow_ptr_leaks
, reg_state(env
, regno
));
1745 static bool is_ctx_reg(struct bpf_verifier_env
*env
, int regno
)
1747 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
1749 return reg
->type
== PTR_TO_CTX
;
1752 static bool is_sk_reg(struct bpf_verifier_env
*env
, int regno
)
1754 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
1756 return type_is_sk_pointer(reg
->type
);
1759 static bool is_pkt_reg(struct bpf_verifier_env
*env
, int regno
)
1761 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
1763 return type_is_pkt_pointer(reg
->type
);
1766 static bool is_flow_key_reg(struct bpf_verifier_env
*env
, int regno
)
1768 const struct bpf_reg_state
*reg
= reg_state(env
, regno
);
1770 /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
1771 return reg
->type
== PTR_TO_FLOW_KEYS
;
1774 static int check_pkt_ptr_alignment(struct bpf_verifier_env
*env
,
1775 const struct bpf_reg_state
*reg
,
1776 int off
, int size
, bool strict
)
1778 struct tnum reg_off
;
1781 /* Byte size accesses are always allowed. */
1782 if (!strict
|| size
== 1)
1785 /* For platforms that do not have a Kconfig enabling
1786 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
1787 * NET_IP_ALIGN is universally set to '2'. And on platforms
1788 * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
1789 * to this code only in strict mode where we want to emulate
1790 * the NET_IP_ALIGN==2 checking. Therefore use an
1791 * unconditional IP align value of '2'.
1795 reg_off
= tnum_add(reg
->var_off
, tnum_const(ip_align
+ reg
->off
+ off
));
1796 if (!tnum_is_aligned(reg_off
, size
)) {
1799 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
1801 "misaligned packet access off %d+%s+%d+%d size %d\n",
1802 ip_align
, tn_buf
, reg
->off
, off
, size
);
1809 static int check_generic_ptr_alignment(struct bpf_verifier_env
*env
,
1810 const struct bpf_reg_state
*reg
,
1811 const char *pointer_desc
,
1812 int off
, int size
, bool strict
)
1814 struct tnum reg_off
;
1816 /* Byte size accesses are always allowed. */
1817 if (!strict
|| size
== 1)
1820 reg_off
= tnum_add(reg
->var_off
, tnum_const(reg
->off
+ off
));
1821 if (!tnum_is_aligned(reg_off
, size
)) {
1824 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
1825 verbose(env
, "misaligned %saccess off %s+%d+%d size %d\n",
1826 pointer_desc
, tn_buf
, reg
->off
, off
, size
);
1833 static int check_ptr_alignment(struct bpf_verifier_env
*env
,
1834 const struct bpf_reg_state
*reg
, int off
,
1835 int size
, bool strict_alignment_once
)
1837 bool strict
= env
->strict_alignment
|| strict_alignment_once
;
1838 const char *pointer_desc
= "";
1840 switch (reg
->type
) {
1842 case PTR_TO_PACKET_META
:
1843 /* Special case, because of NET_IP_ALIGN. Given metadata sits
1844 * right in front, treat it the very same way.
1846 return check_pkt_ptr_alignment(env
, reg
, off
, size
, strict
);
1847 case PTR_TO_FLOW_KEYS
:
1848 pointer_desc
= "flow keys ";
1850 case PTR_TO_MAP_VALUE
:
1851 pointer_desc
= "value ";
1854 pointer_desc
= "context ";
1857 pointer_desc
= "stack ";
1858 /* The stack spill tracking logic in check_stack_write()
1859 * and check_stack_read() relies on stack accesses being
1865 pointer_desc
= "sock ";
1867 case PTR_TO_SOCK_COMMON
:
1868 pointer_desc
= "sock_common ";
1870 case PTR_TO_TCP_SOCK
:
1871 pointer_desc
= "tcp_sock ";
1876 return check_generic_ptr_alignment(env
, reg
, pointer_desc
, off
, size
,
1880 static int update_stack_depth(struct bpf_verifier_env
*env
,
1881 const struct bpf_func_state
*func
,
1884 u16 stack
= env
->subprog_info
[func
->subprogno
].stack_depth
;
1889 /* update known max for given subprogram */
1890 env
->subprog_info
[func
->subprogno
].stack_depth
= -off
;
1894 /* starting from main bpf function walk all instructions of the function
1895 * and recursively walk all callees that given function can call.
1896 * Ignore jump and exit insns.
1897 * Since recursion is prevented by check_cfg() this algorithm
1898 * only needs a local stack of MAX_CALL_FRAMES to remember callsites
1900 static int check_max_stack_depth(struct bpf_verifier_env
*env
)
1902 int depth
= 0, frame
= 0, idx
= 0, i
= 0, subprog_end
;
1903 struct bpf_subprog_info
*subprog
= env
->subprog_info
;
1904 struct bpf_insn
*insn
= env
->prog
->insnsi
;
1905 int ret_insn
[MAX_CALL_FRAMES
];
1906 int ret_prog
[MAX_CALL_FRAMES
];
1909 /* round up to 32-bytes, since this is granularity
1910 * of interpreter stack size
1912 depth
+= round_up(max_t(u32
, subprog
[idx
].stack_depth
, 1), 32);
1913 if (depth
> MAX_BPF_STACK
) {
1914 verbose(env
, "combined stack size of %d calls is %d. Too large\n",
1919 subprog_end
= subprog
[idx
+ 1].start
;
1920 for (; i
< subprog_end
; i
++) {
1921 if (insn
[i
].code
!= (BPF_JMP
| BPF_CALL
))
1923 if (insn
[i
].src_reg
!= BPF_PSEUDO_CALL
)
1925 /* remember insn and function to return to */
1926 ret_insn
[frame
] = i
+ 1;
1927 ret_prog
[frame
] = idx
;
1929 /* find the callee */
1930 i
= i
+ insn
[i
].imm
+ 1;
1931 idx
= find_subprog(env
, i
);
1933 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
1938 if (frame
>= MAX_CALL_FRAMES
) {
1939 verbose(env
, "the call stack of %d frames is too deep !\n",
1945 /* end of for() loop means the last insn of the 'subprog'
1946 * was reached. Doesn't matter whether it was JA or EXIT
1950 depth
-= round_up(max_t(u32
, subprog
[idx
].stack_depth
, 1), 32);
1952 i
= ret_insn
[frame
];
1953 idx
= ret_prog
[frame
];
1957 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1958 static int get_callee_stack_depth(struct bpf_verifier_env
*env
,
1959 const struct bpf_insn
*insn
, int idx
)
1961 int start
= idx
+ insn
->imm
+ 1, subprog
;
1963 subprog
= find_subprog(env
, start
);
1965 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
1969 return env
->subprog_info
[subprog
].stack_depth
;
1973 static int check_ctx_reg(struct bpf_verifier_env
*env
,
1974 const struct bpf_reg_state
*reg
, int regno
)
1976 /* Access to ctx or passing it to a helper is only allowed in
1977 * its original, unmodified form.
1981 verbose(env
, "dereference of modified ctx ptr R%d off=%d disallowed\n",
1986 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
1989 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
1990 verbose(env
, "variable ctx access var_off=%s disallowed\n", tn_buf
);
1997 static int check_tp_buffer_access(struct bpf_verifier_env
*env
,
1998 const struct bpf_reg_state
*reg
,
1999 int regno
, int off
, int size
)
2003 "R%d invalid tracepoint buffer access: off=%d, size=%d",
2007 if (!tnum_is_const(reg
->var_off
) || reg
->var_off
.value
) {
2010 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
2012 "R%d invalid variable buffer offset: off=%d, var_off=%s",
2013 regno
, off
, tn_buf
);
2016 if (off
+ size
> env
->prog
->aux
->max_tp_access
)
2017 env
->prog
->aux
->max_tp_access
= off
+ size
;
2023 /* truncate register to smaller size (in bytes)
2024 * must be called with size < BPF_REG_SIZE
2026 static void coerce_reg_to_size(struct bpf_reg_state
*reg
, int size
)
2030 /* clear high bits in bit representation */
2031 reg
->var_off
= tnum_cast(reg
->var_off
, size
);
2033 /* fix arithmetic bounds */
2034 mask
= ((u64
)1 << (size
* 8)) - 1;
2035 if ((reg
->umin_value
& ~mask
) == (reg
->umax_value
& ~mask
)) {
2036 reg
->umin_value
&= mask
;
2037 reg
->umax_value
&= mask
;
2039 reg
->umin_value
= 0;
2040 reg
->umax_value
= mask
;
2042 reg
->smin_value
= reg
->umin_value
;
2043 reg
->smax_value
= reg
->umax_value
;
2046 /* check whether memory at (regno + off) is accessible for t = (read | write)
2047 * if t==write, value_regno is a register which value is stored into memory
2048 * if t==read, value_regno is a register which will receive the value from memory
2049 * if t==write && value_regno==-1, some unknown value is stored into memory
2050 * if t==read && value_regno==-1, don't care what we read from memory
2052 static int check_mem_access(struct bpf_verifier_env
*env
, int insn_idx
, u32 regno
,
2053 int off
, int bpf_size
, enum bpf_access_type t
,
2054 int value_regno
, bool strict_alignment_once
)
2056 struct bpf_reg_state
*regs
= cur_regs(env
);
2057 struct bpf_reg_state
*reg
= regs
+ regno
;
2058 struct bpf_func_state
*state
;
2061 size
= bpf_size_to_bytes(bpf_size
);
2065 /* alignment checks will add in reg->off themselves */
2066 err
= check_ptr_alignment(env
, reg
, off
, size
, strict_alignment_once
);
2070 /* for access checks, reg->off is just part of off */
2073 if (reg
->type
== PTR_TO_MAP_VALUE
) {
2074 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
2075 is_pointer_value(env
, value_regno
)) {
2076 verbose(env
, "R%d leaks addr into map\n", value_regno
);
2079 err
= check_map_access_type(env
, regno
, off
, size
, t
);
2082 err
= check_map_access(env
, regno
, off
, size
, false);
2083 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
2084 mark_reg_unknown(env
, regs
, value_regno
);
2086 } else if (reg
->type
== PTR_TO_CTX
) {
2087 enum bpf_reg_type reg_type
= SCALAR_VALUE
;
2089 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
2090 is_pointer_value(env
, value_regno
)) {
2091 verbose(env
, "R%d leaks addr into ctx\n", value_regno
);
2095 err
= check_ctx_reg(env
, reg
, regno
);
2099 err
= check_ctx_access(env
, insn_idx
, off
, size
, t
, ®_type
);
2100 if (!err
&& t
== BPF_READ
&& value_regno
>= 0) {
2101 /* ctx access returns either a scalar, or a
2102 * PTR_TO_PACKET[_META,_END]. In the latter
2103 * case, we know the offset is zero.
2105 if (reg_type
== SCALAR_VALUE
) {
2106 mark_reg_unknown(env
, regs
, value_regno
);
2108 mark_reg_known_zero(env
, regs
,
2110 if (reg_type_may_be_null(reg_type
))
2111 regs
[value_regno
].id
= ++env
->id_gen
;
2113 regs
[value_regno
].type
= reg_type
;
2116 } else if (reg
->type
== PTR_TO_STACK
) {
2117 off
+= reg
->var_off
.value
;
2118 err
= check_stack_access(env
, reg
, off
, size
);
2122 state
= func(env
, reg
);
2123 err
= update_stack_depth(env
, state
, off
);
2128 err
= check_stack_write(env
, state
, off
, size
,
2129 value_regno
, insn_idx
);
2131 err
= check_stack_read(env
, state
, off
, size
,
2133 } else if (reg_is_pkt_pointer(reg
)) {
2134 if (t
== BPF_WRITE
&& !may_access_direct_pkt_data(env
, NULL
, t
)) {
2135 verbose(env
, "cannot write into packet\n");
2138 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
2139 is_pointer_value(env
, value_regno
)) {
2140 verbose(env
, "R%d leaks addr into packet\n",
2144 err
= check_packet_access(env
, regno
, off
, size
, false);
2145 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
2146 mark_reg_unknown(env
, regs
, value_regno
);
2147 } else if (reg
->type
== PTR_TO_FLOW_KEYS
) {
2148 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
2149 is_pointer_value(env
, value_regno
)) {
2150 verbose(env
, "R%d leaks addr into flow keys\n",
2155 err
= check_flow_keys_access(env
, off
, size
);
2156 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
2157 mark_reg_unknown(env
, regs
, value_regno
);
2158 } else if (type_is_sk_pointer(reg
->type
)) {
2159 if (t
== BPF_WRITE
) {
2160 verbose(env
, "R%d cannot write into %s\n",
2161 regno
, reg_type_str
[reg
->type
]);
2164 err
= check_sock_access(env
, insn_idx
, regno
, off
, size
, t
);
2165 if (!err
&& value_regno
>= 0)
2166 mark_reg_unknown(env
, regs
, value_regno
);
2167 } else if (reg
->type
== PTR_TO_TP_BUFFER
) {
2168 err
= check_tp_buffer_access(env
, reg
, regno
, off
, size
);
2169 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
2170 mark_reg_unknown(env
, regs
, value_regno
);
2172 verbose(env
, "R%d invalid mem access '%s'\n", regno
,
2173 reg_type_str
[reg
->type
]);
2177 if (!err
&& size
< BPF_REG_SIZE
&& value_regno
>= 0 && t
== BPF_READ
&&
2178 regs
[value_regno
].type
== SCALAR_VALUE
) {
2179 /* b/h/w load zero-extends, mark upper bits as known 0 */
2180 coerce_reg_to_size(®s
[value_regno
], size
);
2185 static int check_xadd(struct bpf_verifier_env
*env
, int insn_idx
, struct bpf_insn
*insn
)
2189 if ((BPF_SIZE(insn
->code
) != BPF_W
&& BPF_SIZE(insn
->code
) != BPF_DW
) ||
2191 verbose(env
, "BPF_XADD uses reserved fields\n");
2195 /* check src1 operand */
2196 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
2200 /* check src2 operand */
2201 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
2205 if (is_pointer_value(env
, insn
->src_reg
)) {
2206 verbose(env
, "R%d leaks addr into mem\n", insn
->src_reg
);
2210 if (is_ctx_reg(env
, insn
->dst_reg
) ||
2211 is_pkt_reg(env
, insn
->dst_reg
) ||
2212 is_flow_key_reg(env
, insn
->dst_reg
) ||
2213 is_sk_reg(env
, insn
->dst_reg
)) {
2214 verbose(env
, "BPF_XADD stores into R%d %s is not allowed\n",
2216 reg_type_str
[reg_state(env
, insn
->dst_reg
)->type
]);
2220 /* check whether atomic_add can read the memory */
2221 err
= check_mem_access(env
, insn_idx
, insn
->dst_reg
, insn
->off
,
2222 BPF_SIZE(insn
->code
), BPF_READ
, -1, true);
2226 /* check whether atomic_add can write into the same memory */
2227 return check_mem_access(env
, insn_idx
, insn
->dst_reg
, insn
->off
,
2228 BPF_SIZE(insn
->code
), BPF_WRITE
, -1, true);
2231 static int __check_stack_boundary(struct bpf_verifier_env
*env
, u32 regno
,
2232 int off
, int access_size
,
2233 bool zero_size_allowed
)
2235 struct bpf_reg_state
*reg
= reg_state(env
, regno
);
2237 if (off
>= 0 || off
< -MAX_BPF_STACK
|| off
+ access_size
> 0 ||
2238 access_size
< 0 || (access_size
== 0 && !zero_size_allowed
)) {
2239 if (tnum_is_const(reg
->var_off
)) {
2240 verbose(env
, "invalid stack type R%d off=%d access_size=%d\n",
2241 regno
, off
, access_size
);
2245 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
2246 verbose(env
, "invalid stack type R%d var_off=%s access_size=%d\n",
2247 regno
, tn_buf
, access_size
);
2254 /* when register 'regno' is passed into function that will read 'access_size'
2255 * bytes from that pointer, make sure that it's within stack boundary
2256 * and all elements of stack are initialized.
2257 * Unlike most pointer bounds-checking functions, this one doesn't take an
2258 * 'off' argument, so it has to add in reg->off itself.
2260 static int check_stack_boundary(struct bpf_verifier_env
*env
, int regno
,
2261 int access_size
, bool zero_size_allowed
,
2262 struct bpf_call_arg_meta
*meta
)
2264 struct bpf_reg_state
*reg
= reg_state(env
, regno
);
2265 struct bpf_func_state
*state
= func(env
, reg
);
2266 int err
, min_off
, max_off
, i
, slot
, spi
;
2268 if (reg
->type
!= PTR_TO_STACK
) {
2269 /* Allow zero-byte read from NULL, regardless of pointer type */
2270 if (zero_size_allowed
&& access_size
== 0 &&
2271 register_is_null(reg
))
2274 verbose(env
, "R%d type=%s expected=%s\n", regno
,
2275 reg_type_str
[reg
->type
],
2276 reg_type_str
[PTR_TO_STACK
]);
2280 if (tnum_is_const(reg
->var_off
)) {
2281 min_off
= max_off
= reg
->var_off
.value
+ reg
->off
;
2282 err
= __check_stack_boundary(env
, regno
, min_off
, access_size
,
2287 /* Variable offset is prohibited for unprivileged mode for
2288 * simplicity since it requires corresponding support in
2289 * Spectre masking for stack ALU.
2290 * See also retrieve_ptr_limit().
2292 if (!env
->allow_ptr_leaks
) {
2295 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
2296 verbose(env
, "R%d indirect variable offset stack access prohibited for !root, var_off=%s\n",
2300 /* Only initialized buffer on stack is allowed to be accessed
2301 * with variable offset. With uninitialized buffer it's hard to
2302 * guarantee that whole memory is marked as initialized on
2303 * helper return since specific bounds are unknown what may
2304 * cause uninitialized stack leaking.
2306 if (meta
&& meta
->raw_mode
)
2309 if (reg
->smax_value
>= BPF_MAX_VAR_OFF
||
2310 reg
->smax_value
<= -BPF_MAX_VAR_OFF
) {
2311 verbose(env
, "R%d unbounded indirect variable offset stack access\n",
2315 min_off
= reg
->smin_value
+ reg
->off
;
2316 max_off
= reg
->smax_value
+ reg
->off
;
2317 err
= __check_stack_boundary(env
, regno
, min_off
, access_size
,
2320 verbose(env
, "R%d min value is outside of stack bound\n",
2324 err
= __check_stack_boundary(env
, regno
, max_off
, access_size
,
2327 verbose(env
, "R%d max value is outside of stack bound\n",
2333 if (meta
&& meta
->raw_mode
) {
2334 meta
->access_size
= access_size
;
2335 meta
->regno
= regno
;
2339 for (i
= min_off
; i
< max_off
+ access_size
; i
++) {
2343 spi
= slot
/ BPF_REG_SIZE
;
2344 if (state
->allocated_stack
<= slot
)
2346 stype
= &state
->stack
[spi
].slot_type
[slot
% BPF_REG_SIZE
];
2347 if (*stype
== STACK_MISC
)
2349 if (*stype
== STACK_ZERO
) {
2350 /* helper can write anything into the stack */
2351 *stype
= STACK_MISC
;
2355 if (tnum_is_const(reg
->var_off
)) {
2356 verbose(env
, "invalid indirect read from stack off %d+%d size %d\n",
2357 min_off
, i
- min_off
, access_size
);
2361 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
2362 verbose(env
, "invalid indirect read from stack var_off %s+%d size %d\n",
2363 tn_buf
, i
- min_off
, access_size
);
2367 /* reading any byte out of 8-byte 'spill_slot' will cause
2368 * the whole slot to be marked as 'read'
2370 mark_reg_read(env
, &state
->stack
[spi
].spilled_ptr
,
2371 state
->stack
[spi
].spilled_ptr
.parent
);
2373 return update_stack_depth(env
, state
, min_off
);
2376 static int check_helper_mem_access(struct bpf_verifier_env
*env
, int regno
,
2377 int access_size
, bool zero_size_allowed
,
2378 struct bpf_call_arg_meta
*meta
)
2380 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
2382 switch (reg
->type
) {
2384 case PTR_TO_PACKET_META
:
2385 return check_packet_access(env
, regno
, reg
->off
, access_size
,
2387 case PTR_TO_MAP_VALUE
:
2388 if (check_map_access_type(env
, regno
, reg
->off
, access_size
,
2389 meta
&& meta
->raw_mode
? BPF_WRITE
:
2392 return check_map_access(env
, regno
, reg
->off
, access_size
,
2394 default: /* scalar_value|ptr_to_stack or invalid ptr */
2395 return check_stack_boundary(env
, regno
, access_size
,
2396 zero_size_allowed
, meta
);
2400 /* Implementation details:
2401 * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL
2402 * Two bpf_map_lookups (even with the same key) will have different reg->id.
2403 * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after
2404 * value_or_null->value transition, since the verifier only cares about
2405 * the range of access to valid map value pointer and doesn't care about actual
2406 * address of the map element.
2407 * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
2408 * reg->id > 0 after value_or_null->value transition. By doing so
2409 * two bpf_map_lookups will be considered two different pointers that
2410 * point to different bpf_spin_locks.
2411 * The verifier allows taking only one bpf_spin_lock at a time to avoid
2413 * Since only one bpf_spin_lock is allowed the checks are simpler than
2414 * reg_is_refcounted() logic. The verifier needs to remember only
2415 * one spin_lock instead of array of acquired_refs.
2416 * cur_state->active_spin_lock remembers which map value element got locked
2417 * and clears it after bpf_spin_unlock.
2419 static int process_spin_lock(struct bpf_verifier_env
*env
, int regno
,
2422 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
2423 struct bpf_verifier_state
*cur
= env
->cur_state
;
2424 bool is_const
= tnum_is_const(reg
->var_off
);
2425 struct bpf_map
*map
= reg
->map_ptr
;
2426 u64 val
= reg
->var_off
.value
;
2428 if (reg
->type
!= PTR_TO_MAP_VALUE
) {
2429 verbose(env
, "R%d is not a pointer to map_value\n", regno
);
2434 "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
2440 "map '%s' has to have BTF in order to use bpf_spin_lock\n",
2444 if (!map_value_has_spin_lock(map
)) {
2445 if (map
->spin_lock_off
== -E2BIG
)
2447 "map '%s' has more than one 'struct bpf_spin_lock'\n",
2449 else if (map
->spin_lock_off
== -ENOENT
)
2451 "map '%s' doesn't have 'struct bpf_spin_lock'\n",
2455 "map '%s' is not a struct type or bpf_spin_lock is mangled\n",
2459 if (map
->spin_lock_off
!= val
+ reg
->off
) {
2460 verbose(env
, "off %lld doesn't point to 'struct bpf_spin_lock'\n",
2465 if (cur
->active_spin_lock
) {
2467 "Locking two bpf_spin_locks are not allowed\n");
2470 cur
->active_spin_lock
= reg
->id
;
2472 if (!cur
->active_spin_lock
) {
2473 verbose(env
, "bpf_spin_unlock without taking a lock\n");
2476 if (cur
->active_spin_lock
!= reg
->id
) {
2477 verbose(env
, "bpf_spin_unlock of different lock\n");
2480 cur
->active_spin_lock
= 0;
2485 static bool arg_type_is_mem_ptr(enum bpf_arg_type type
)
2487 return type
== ARG_PTR_TO_MEM
||
2488 type
== ARG_PTR_TO_MEM_OR_NULL
||
2489 type
== ARG_PTR_TO_UNINIT_MEM
;
2492 static bool arg_type_is_mem_size(enum bpf_arg_type type
)
2494 return type
== ARG_CONST_SIZE
||
2495 type
== ARG_CONST_SIZE_OR_ZERO
;
2498 static bool arg_type_is_int_ptr(enum bpf_arg_type type
)
2500 return type
== ARG_PTR_TO_INT
||
2501 type
== ARG_PTR_TO_LONG
;
2504 static int int_ptr_type_to_size(enum bpf_arg_type type
)
2506 if (type
== ARG_PTR_TO_INT
)
2508 else if (type
== ARG_PTR_TO_LONG
)
2514 static int check_func_arg(struct bpf_verifier_env
*env
, u32 regno
,
2515 enum bpf_arg_type arg_type
,
2516 struct bpf_call_arg_meta
*meta
)
2518 struct bpf_reg_state
*regs
= cur_regs(env
), *reg
= ®s
[regno
];
2519 enum bpf_reg_type expected_type
, type
= reg
->type
;
2522 if (arg_type
== ARG_DONTCARE
)
2525 err
= check_reg_arg(env
, regno
, SRC_OP
);
2529 if (arg_type
== ARG_ANYTHING
) {
2530 if (is_pointer_value(env
, regno
)) {
2531 verbose(env
, "R%d leaks addr into helper function\n",
2538 if (type_is_pkt_pointer(type
) &&
2539 !may_access_direct_pkt_data(env
, meta
, BPF_READ
)) {
2540 verbose(env
, "helper access to the packet is not allowed\n");
2544 if (arg_type
== ARG_PTR_TO_MAP_KEY
||
2545 arg_type
== ARG_PTR_TO_MAP_VALUE
||
2546 arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
||
2547 arg_type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
) {
2548 expected_type
= PTR_TO_STACK
;
2549 if (register_is_null(reg
) &&
2550 arg_type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
)
2551 /* final test in check_stack_boundary() */;
2552 else if (!type_is_pkt_pointer(type
) &&
2553 type
!= PTR_TO_MAP_VALUE
&&
2554 type
!= expected_type
)
2556 } else if (arg_type
== ARG_CONST_SIZE
||
2557 arg_type
== ARG_CONST_SIZE_OR_ZERO
) {
2558 expected_type
= SCALAR_VALUE
;
2559 if (type
!= expected_type
)
2561 } else if (arg_type
== ARG_CONST_MAP_PTR
) {
2562 expected_type
= CONST_PTR_TO_MAP
;
2563 if (type
!= expected_type
)
2565 } else if (arg_type
== ARG_PTR_TO_CTX
) {
2566 expected_type
= PTR_TO_CTX
;
2567 if (type
!= expected_type
)
2569 err
= check_ctx_reg(env
, reg
, regno
);
2572 } else if (arg_type
== ARG_PTR_TO_SOCK_COMMON
) {
2573 expected_type
= PTR_TO_SOCK_COMMON
;
2574 /* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */
2575 if (!type_is_sk_pointer(type
))
2577 if (reg
->ref_obj_id
) {
2578 if (meta
->ref_obj_id
) {
2579 verbose(env
, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
2580 regno
, reg
->ref_obj_id
,
2584 meta
->ref_obj_id
= reg
->ref_obj_id
;
2586 } else if (arg_type
== ARG_PTR_TO_SOCKET
) {
2587 expected_type
= PTR_TO_SOCKET
;
2588 if (type
!= expected_type
)
2590 } else if (arg_type
== ARG_PTR_TO_SPIN_LOCK
) {
2591 if (meta
->func_id
== BPF_FUNC_spin_lock
) {
2592 if (process_spin_lock(env
, regno
, true))
2594 } else if (meta
->func_id
== BPF_FUNC_spin_unlock
) {
2595 if (process_spin_lock(env
, regno
, false))
2598 verbose(env
, "verifier internal error\n");
2601 } else if (arg_type_is_mem_ptr(arg_type
)) {
2602 expected_type
= PTR_TO_STACK
;
2603 /* One exception here. In case function allows for NULL to be
2604 * passed in as argument, it's a SCALAR_VALUE type. Final test
2605 * happens during stack boundary checking.
2607 if (register_is_null(reg
) &&
2608 arg_type
== ARG_PTR_TO_MEM_OR_NULL
)
2609 /* final test in check_stack_boundary() */;
2610 else if (!type_is_pkt_pointer(type
) &&
2611 type
!= PTR_TO_MAP_VALUE
&&
2612 type
!= expected_type
)
2614 meta
->raw_mode
= arg_type
== ARG_PTR_TO_UNINIT_MEM
;
2615 } else if (arg_type_is_int_ptr(arg_type
)) {
2616 expected_type
= PTR_TO_STACK
;
2617 if (!type_is_pkt_pointer(type
) &&
2618 type
!= PTR_TO_MAP_VALUE
&&
2619 type
!= expected_type
)
2622 verbose(env
, "unsupported arg_type %d\n", arg_type
);
2626 if (arg_type
== ARG_CONST_MAP_PTR
) {
2627 /* bpf_map_xxx(map_ptr) call: remember that map_ptr */
2628 meta
->map_ptr
= reg
->map_ptr
;
2629 } else if (arg_type
== ARG_PTR_TO_MAP_KEY
) {
2630 /* bpf_map_xxx(..., map_ptr, ..., key) call:
2631 * check that [key, key + map->key_size) are within
2632 * stack limits and initialized
2634 if (!meta
->map_ptr
) {
2635 /* in function declaration map_ptr must come before
2636 * map_key, so that it's verified and known before
2637 * we have to check map_key here. Otherwise it means
2638 * that kernel subsystem misconfigured verifier
2640 verbose(env
, "invalid map_ptr to access map->key\n");
2643 err
= check_helper_mem_access(env
, regno
,
2644 meta
->map_ptr
->key_size
, false,
2646 } else if (arg_type
== ARG_PTR_TO_MAP_VALUE
||
2647 (arg_type
== ARG_PTR_TO_MAP_VALUE_OR_NULL
&&
2648 !register_is_null(reg
)) ||
2649 arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
) {
2650 /* bpf_map_xxx(..., map_ptr, ..., value) call:
2651 * check [value, value + map->value_size) validity
2653 if (!meta
->map_ptr
) {
2654 /* kernel subsystem misconfigured verifier */
2655 verbose(env
, "invalid map_ptr to access map->value\n");
2658 meta
->raw_mode
= (arg_type
== ARG_PTR_TO_UNINIT_MAP_VALUE
);
2659 err
= check_helper_mem_access(env
, regno
,
2660 meta
->map_ptr
->value_size
, false,
2662 } else if (arg_type_is_mem_size(arg_type
)) {
2663 bool zero_size_allowed
= (arg_type
== ARG_CONST_SIZE_OR_ZERO
);
2665 /* remember the mem_size which may be used later
2666 * to refine return values.
2668 meta
->msize_smax_value
= reg
->smax_value
;
2669 meta
->msize_umax_value
= reg
->umax_value
;
2671 /* The register is SCALAR_VALUE; the access check
2672 * happens using its boundaries.
2674 if (!tnum_is_const(reg
->var_off
))
2675 /* For unprivileged variable accesses, disable raw
2676 * mode so that the program is required to
2677 * initialize all the memory that the helper could
2678 * just partially fill up.
2682 if (reg
->smin_value
< 0) {
2683 verbose(env
, "R%d min value is negative, either use unsigned or 'var &= const'\n",
2688 if (reg
->umin_value
== 0) {
2689 err
= check_helper_mem_access(env
, regno
- 1, 0,
2696 if (reg
->umax_value
>= BPF_MAX_VAR_SIZ
) {
2697 verbose(env
, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
2701 err
= check_helper_mem_access(env
, regno
- 1,
2703 zero_size_allowed
, meta
);
2704 } else if (arg_type_is_int_ptr(arg_type
)) {
2705 int size
= int_ptr_type_to_size(arg_type
);
2707 err
= check_helper_mem_access(env
, regno
, size
, false, meta
);
2710 err
= check_ptr_alignment(env
, reg
, 0, size
, true);
2715 verbose(env
, "R%d type=%s expected=%s\n", regno
,
2716 reg_type_str
[type
], reg_type_str
[expected_type
]);
2720 static int check_map_func_compatibility(struct bpf_verifier_env
*env
,
2721 struct bpf_map
*map
, int func_id
)
2726 /* We need a two way check, first is from map perspective ... */
2727 switch (map
->map_type
) {
2728 case BPF_MAP_TYPE_PROG_ARRAY
:
2729 if (func_id
!= BPF_FUNC_tail_call
)
2732 case BPF_MAP_TYPE_PERF_EVENT_ARRAY
:
2733 if (func_id
!= BPF_FUNC_perf_event_read
&&
2734 func_id
!= BPF_FUNC_perf_event_output
&&
2735 func_id
!= BPF_FUNC_perf_event_read_value
)
2738 case BPF_MAP_TYPE_STACK_TRACE
:
2739 if (func_id
!= BPF_FUNC_get_stackid
)
2742 case BPF_MAP_TYPE_CGROUP_ARRAY
:
2743 if (func_id
!= BPF_FUNC_skb_under_cgroup
&&
2744 func_id
!= BPF_FUNC_current_task_under_cgroup
)
2747 case BPF_MAP_TYPE_CGROUP_STORAGE
:
2748 case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
:
2749 if (func_id
!= BPF_FUNC_get_local_storage
)
2752 /* devmap returns a pointer to a live net_device ifindex that we cannot
2753 * allow to be modified from bpf side. So do not allow lookup elements
2756 case BPF_MAP_TYPE_DEVMAP
:
2757 if (func_id
!= BPF_FUNC_redirect_map
)
2760 /* Restrict bpf side of cpumap and xskmap, open when use-cases
2763 case BPF_MAP_TYPE_CPUMAP
:
2764 case BPF_MAP_TYPE_XSKMAP
:
2765 if (func_id
!= BPF_FUNC_redirect_map
)
2768 case BPF_MAP_TYPE_ARRAY_OF_MAPS
:
2769 case BPF_MAP_TYPE_HASH_OF_MAPS
:
2770 if (func_id
!= BPF_FUNC_map_lookup_elem
)
2773 case BPF_MAP_TYPE_SOCKMAP
:
2774 if (func_id
!= BPF_FUNC_sk_redirect_map
&&
2775 func_id
!= BPF_FUNC_sock_map_update
&&
2776 func_id
!= BPF_FUNC_map_delete_elem
&&
2777 func_id
!= BPF_FUNC_msg_redirect_map
)
2780 case BPF_MAP_TYPE_SOCKHASH
:
2781 if (func_id
!= BPF_FUNC_sk_redirect_hash
&&
2782 func_id
!= BPF_FUNC_sock_hash_update
&&
2783 func_id
!= BPF_FUNC_map_delete_elem
&&
2784 func_id
!= BPF_FUNC_msg_redirect_hash
)
2787 case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY
:
2788 if (func_id
!= BPF_FUNC_sk_select_reuseport
)
2791 case BPF_MAP_TYPE_QUEUE
:
2792 case BPF_MAP_TYPE_STACK
:
2793 if (func_id
!= BPF_FUNC_map_peek_elem
&&
2794 func_id
!= BPF_FUNC_map_pop_elem
&&
2795 func_id
!= BPF_FUNC_map_push_elem
)
2798 case BPF_MAP_TYPE_SK_STORAGE
:
2799 if (func_id
!= BPF_FUNC_sk_storage_get
&&
2800 func_id
!= BPF_FUNC_sk_storage_delete
)
2807 /* ... and second from the function itself. */
2809 case BPF_FUNC_tail_call
:
2810 if (map
->map_type
!= BPF_MAP_TYPE_PROG_ARRAY
)
2812 if (env
->subprog_cnt
> 1) {
2813 verbose(env
, "tail_calls are not allowed in programs with bpf-to-bpf calls\n");
2817 case BPF_FUNC_perf_event_read
:
2818 case BPF_FUNC_perf_event_output
:
2819 case BPF_FUNC_perf_event_read_value
:
2820 if (map
->map_type
!= BPF_MAP_TYPE_PERF_EVENT_ARRAY
)
2823 case BPF_FUNC_get_stackid
:
2824 if (map
->map_type
!= BPF_MAP_TYPE_STACK_TRACE
)
2827 case BPF_FUNC_current_task_under_cgroup
:
2828 case BPF_FUNC_skb_under_cgroup
:
2829 if (map
->map_type
!= BPF_MAP_TYPE_CGROUP_ARRAY
)
2832 case BPF_FUNC_redirect_map
:
2833 if (map
->map_type
!= BPF_MAP_TYPE_DEVMAP
&&
2834 map
->map_type
!= BPF_MAP_TYPE_CPUMAP
&&
2835 map
->map_type
!= BPF_MAP_TYPE_XSKMAP
)
2838 case BPF_FUNC_sk_redirect_map
:
2839 case BPF_FUNC_msg_redirect_map
:
2840 case BPF_FUNC_sock_map_update
:
2841 if (map
->map_type
!= BPF_MAP_TYPE_SOCKMAP
)
2844 case BPF_FUNC_sk_redirect_hash
:
2845 case BPF_FUNC_msg_redirect_hash
:
2846 case BPF_FUNC_sock_hash_update
:
2847 if (map
->map_type
!= BPF_MAP_TYPE_SOCKHASH
)
2850 case BPF_FUNC_get_local_storage
:
2851 if (map
->map_type
!= BPF_MAP_TYPE_CGROUP_STORAGE
&&
2852 map
->map_type
!= BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
)
2855 case BPF_FUNC_sk_select_reuseport
:
2856 if (map
->map_type
!= BPF_MAP_TYPE_REUSEPORT_SOCKARRAY
)
2859 case BPF_FUNC_map_peek_elem
:
2860 case BPF_FUNC_map_pop_elem
:
2861 case BPF_FUNC_map_push_elem
:
2862 if (map
->map_type
!= BPF_MAP_TYPE_QUEUE
&&
2863 map
->map_type
!= BPF_MAP_TYPE_STACK
)
2866 case BPF_FUNC_sk_storage_get
:
2867 case BPF_FUNC_sk_storage_delete
:
2868 if (map
->map_type
!= BPF_MAP_TYPE_SK_STORAGE
)
2877 verbose(env
, "cannot pass map_type %d into func %s#%d\n",
2878 map
->map_type
, func_id_name(func_id
), func_id
);
2882 static bool check_raw_mode_ok(const struct bpf_func_proto
*fn
)
2886 if (fn
->arg1_type
== ARG_PTR_TO_UNINIT_MEM
)
2888 if (fn
->arg2_type
== ARG_PTR_TO_UNINIT_MEM
)
2890 if (fn
->arg3_type
== ARG_PTR_TO_UNINIT_MEM
)
2892 if (fn
->arg4_type
== ARG_PTR_TO_UNINIT_MEM
)
2894 if (fn
->arg5_type
== ARG_PTR_TO_UNINIT_MEM
)
2897 /* We only support one arg being in raw mode at the moment,
2898 * which is sufficient for the helper functions we have
2904 static bool check_args_pair_invalid(enum bpf_arg_type arg_curr
,
2905 enum bpf_arg_type arg_next
)
2907 return (arg_type_is_mem_ptr(arg_curr
) &&
2908 !arg_type_is_mem_size(arg_next
)) ||
2909 (!arg_type_is_mem_ptr(arg_curr
) &&
2910 arg_type_is_mem_size(arg_next
));
2913 static bool check_arg_pair_ok(const struct bpf_func_proto
*fn
)
2915 /* bpf_xxx(..., buf, len) call will access 'len'
2916 * bytes from memory 'buf'. Both arg types need
2917 * to be paired, so make sure there's no buggy
2918 * helper function specification.
2920 if (arg_type_is_mem_size(fn
->arg1_type
) ||
2921 arg_type_is_mem_ptr(fn
->arg5_type
) ||
2922 check_args_pair_invalid(fn
->arg1_type
, fn
->arg2_type
) ||
2923 check_args_pair_invalid(fn
->arg2_type
, fn
->arg3_type
) ||
2924 check_args_pair_invalid(fn
->arg3_type
, fn
->arg4_type
) ||
2925 check_args_pair_invalid(fn
->arg4_type
, fn
->arg5_type
))
2931 static bool check_refcount_ok(const struct bpf_func_proto
*fn
, int func_id
)
2935 if (arg_type_may_be_refcounted(fn
->arg1_type
))
2937 if (arg_type_may_be_refcounted(fn
->arg2_type
))
2939 if (arg_type_may_be_refcounted(fn
->arg3_type
))
2941 if (arg_type_may_be_refcounted(fn
->arg4_type
))
2943 if (arg_type_may_be_refcounted(fn
->arg5_type
))
2946 /* A reference acquiring function cannot acquire
2947 * another refcounted ptr.
2949 if (is_acquire_function(func_id
) && count
)
2952 /* We only support one arg being unreferenced at the moment,
2953 * which is sufficient for the helper functions we have right now.
2958 static int check_func_proto(const struct bpf_func_proto
*fn
, int func_id
)
2960 return check_raw_mode_ok(fn
) &&
2961 check_arg_pair_ok(fn
) &&
2962 check_refcount_ok(fn
, func_id
) ? 0 : -EINVAL
;
2965 /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
2966 * are now invalid, so turn them into unknown SCALAR_VALUE.
2968 static void __clear_all_pkt_pointers(struct bpf_verifier_env
*env
,
2969 struct bpf_func_state
*state
)
2971 struct bpf_reg_state
*regs
= state
->regs
, *reg
;
2974 for (i
= 0; i
< MAX_BPF_REG
; i
++)
2975 if (reg_is_pkt_pointer_any(®s
[i
]))
2976 mark_reg_unknown(env
, regs
, i
);
2978 bpf_for_each_spilled_reg(i
, state
, reg
) {
2981 if (reg_is_pkt_pointer_any(reg
))
2982 __mark_reg_unknown(reg
);
2986 static void clear_all_pkt_pointers(struct bpf_verifier_env
*env
)
2988 struct bpf_verifier_state
*vstate
= env
->cur_state
;
2991 for (i
= 0; i
<= vstate
->curframe
; i
++)
2992 __clear_all_pkt_pointers(env
, vstate
->frame
[i
]);
2995 static void release_reg_references(struct bpf_verifier_env
*env
,
2996 struct bpf_func_state
*state
,
2999 struct bpf_reg_state
*regs
= state
->regs
, *reg
;
3002 for (i
= 0; i
< MAX_BPF_REG
; i
++)
3003 if (regs
[i
].ref_obj_id
== ref_obj_id
)
3004 mark_reg_unknown(env
, regs
, i
);
3006 bpf_for_each_spilled_reg(i
, state
, reg
) {
3009 if (reg
->ref_obj_id
== ref_obj_id
)
3010 __mark_reg_unknown(reg
);
3014 /* The pointer with the specified id has released its reference to kernel
3015 * resources. Identify all copies of the same pointer and clear the reference.
3017 static int release_reference(struct bpf_verifier_env
*env
,
3020 struct bpf_verifier_state
*vstate
= env
->cur_state
;
3024 err
= release_reference_state(cur_func(env
), ref_obj_id
);
3028 for (i
= 0; i
<= vstate
->curframe
; i
++)
3029 release_reg_references(env
, vstate
->frame
[i
], ref_obj_id
);
3034 static int check_func_call(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
,
3037 struct bpf_verifier_state
*state
= env
->cur_state
;
3038 struct bpf_func_state
*caller
, *callee
;
3039 int i
, err
, subprog
, target_insn
;
3041 if (state
->curframe
+ 1 >= MAX_CALL_FRAMES
) {
3042 verbose(env
, "the call stack of %d frames is too deep\n",
3043 state
->curframe
+ 2);
3047 target_insn
= *insn_idx
+ insn
->imm
;
3048 subprog
= find_subprog(env
, target_insn
+ 1);
3050 verbose(env
, "verifier bug. No program starts at insn %d\n",
3055 caller
= state
->frame
[state
->curframe
];
3056 if (state
->frame
[state
->curframe
+ 1]) {
3057 verbose(env
, "verifier bug. Frame %d already allocated\n",
3058 state
->curframe
+ 1);
3062 callee
= kzalloc(sizeof(*callee
), GFP_KERNEL
);
3065 state
->frame
[state
->curframe
+ 1] = callee
;
3067 /* callee cannot access r0, r6 - r9 for reading and has to write
3068 * into its own stack before reading from it.
3069 * callee can read/write into caller's stack
3071 init_func_state(env
, callee
,
3072 /* remember the callsite, it will be used by bpf_exit */
3073 *insn_idx
/* callsite */,
3074 state
->curframe
+ 1 /* frameno within this callchain */,
3075 subprog
/* subprog number within this prog */);
3077 /* Transfer references to the callee */
3078 err
= transfer_reference_state(callee
, caller
);
3082 /* copy r1 - r5 args that callee can access. The copy includes parent
3083 * pointers, which connects us up to the liveness chain
3085 for (i
= BPF_REG_1
; i
<= BPF_REG_5
; i
++)
3086 callee
->regs
[i
] = caller
->regs
[i
];
3088 /* after the call registers r0 - r5 were scratched */
3089 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
3090 mark_reg_not_init(env
, caller
->regs
, caller_saved
[i
]);
3091 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
3094 /* only increment it after check_reg_arg() finished */
3097 /* and go analyze first insn of the callee */
3098 *insn_idx
= target_insn
;
3100 if (env
->log
.level
& BPF_LOG_LEVEL
) {
3101 verbose(env
, "caller:\n");
3102 print_verifier_state(env
, caller
);
3103 verbose(env
, "callee:\n");
3104 print_verifier_state(env
, callee
);
3109 static int prepare_func_exit(struct bpf_verifier_env
*env
, int *insn_idx
)
3111 struct bpf_verifier_state
*state
= env
->cur_state
;
3112 struct bpf_func_state
*caller
, *callee
;
3113 struct bpf_reg_state
*r0
;
3116 callee
= state
->frame
[state
->curframe
];
3117 r0
= &callee
->regs
[BPF_REG_0
];
3118 if (r0
->type
== PTR_TO_STACK
) {
3119 /* technically it's ok to return caller's stack pointer
3120 * (or caller's caller's pointer) back to the caller,
3121 * since these pointers are valid. Only current stack
3122 * pointer will be invalid as soon as function exits,
3123 * but let's be conservative
3125 verbose(env
, "cannot return stack pointer to the caller\n");
3130 caller
= state
->frame
[state
->curframe
];
3131 /* return to the caller whatever r0 had in the callee */
3132 caller
->regs
[BPF_REG_0
] = *r0
;
3134 /* Transfer references to the caller */
3135 err
= transfer_reference_state(caller
, callee
);
3139 *insn_idx
= callee
->callsite
+ 1;
3140 if (env
->log
.level
& BPF_LOG_LEVEL
) {
3141 verbose(env
, "returning from callee:\n");
3142 print_verifier_state(env
, callee
);
3143 verbose(env
, "to caller at %d:\n", *insn_idx
);
3144 print_verifier_state(env
, caller
);
3146 /* clear everything in the callee */
3147 free_func_state(callee
);
3148 state
->frame
[state
->curframe
+ 1] = NULL
;
3152 static void do_refine_retval_range(struct bpf_reg_state
*regs
, int ret_type
,
3154 struct bpf_call_arg_meta
*meta
)
3156 struct bpf_reg_state
*ret_reg
= ®s
[BPF_REG_0
];
3158 if (ret_type
!= RET_INTEGER
||
3159 (func_id
!= BPF_FUNC_get_stack
&&
3160 func_id
!= BPF_FUNC_probe_read_str
))
3163 ret_reg
->smax_value
= meta
->msize_smax_value
;
3164 ret_reg
->umax_value
= meta
->msize_umax_value
;
3165 __reg_deduce_bounds(ret_reg
);
3166 __reg_bound_offset(ret_reg
);
3170 record_func_map(struct bpf_verifier_env
*env
, struct bpf_call_arg_meta
*meta
,
3171 int func_id
, int insn_idx
)
3173 struct bpf_insn_aux_data
*aux
= &env
->insn_aux_data
[insn_idx
];
3174 struct bpf_map
*map
= meta
->map_ptr
;
3176 if (func_id
!= BPF_FUNC_tail_call
&&
3177 func_id
!= BPF_FUNC_map_lookup_elem
&&
3178 func_id
!= BPF_FUNC_map_update_elem
&&
3179 func_id
!= BPF_FUNC_map_delete_elem
&&
3180 func_id
!= BPF_FUNC_map_push_elem
&&
3181 func_id
!= BPF_FUNC_map_pop_elem
&&
3182 func_id
!= BPF_FUNC_map_peek_elem
)
3186 verbose(env
, "kernel subsystem misconfigured verifier\n");
3190 /* In case of read-only, some additional restrictions
3191 * need to be applied in order to prevent altering the
3192 * state of the map from program side.
3194 if ((map
->map_flags
& BPF_F_RDONLY_PROG
) &&
3195 (func_id
== BPF_FUNC_map_delete_elem
||
3196 func_id
== BPF_FUNC_map_update_elem
||
3197 func_id
== BPF_FUNC_map_push_elem
||
3198 func_id
== BPF_FUNC_map_pop_elem
)) {
3199 verbose(env
, "write into map forbidden\n");
3203 if (!BPF_MAP_PTR(aux
->map_state
))
3204 bpf_map_ptr_store(aux
, meta
->map_ptr
,
3205 meta
->map_ptr
->unpriv_array
);
3206 else if (BPF_MAP_PTR(aux
->map_state
) != meta
->map_ptr
)
3207 bpf_map_ptr_store(aux
, BPF_MAP_PTR_POISON
,
3208 meta
->map_ptr
->unpriv_array
);
3212 static int check_reference_leak(struct bpf_verifier_env
*env
)
3214 struct bpf_func_state
*state
= cur_func(env
);
3217 for (i
= 0; i
< state
->acquired_refs
; i
++) {
3218 verbose(env
, "Unreleased reference id=%d alloc_insn=%d\n",
3219 state
->refs
[i
].id
, state
->refs
[i
].insn_idx
);
3221 return state
->acquired_refs
? -EINVAL
: 0;
3224 static int check_helper_call(struct bpf_verifier_env
*env
, int func_id
, int insn_idx
)
3226 const struct bpf_func_proto
*fn
= NULL
;
3227 struct bpf_reg_state
*regs
;
3228 struct bpf_call_arg_meta meta
;
3232 /* find function prototype */
3233 if (func_id
< 0 || func_id
>= __BPF_FUNC_MAX_ID
) {
3234 verbose(env
, "invalid func %s#%d\n", func_id_name(func_id
),
3239 if (env
->ops
->get_func_proto
)
3240 fn
= env
->ops
->get_func_proto(func_id
, env
->prog
);
3242 verbose(env
, "unknown func %s#%d\n", func_id_name(func_id
),
3247 /* eBPF programs must be GPL compatible to use GPL-ed functions */
3248 if (!env
->prog
->gpl_compatible
&& fn
->gpl_only
) {
3249 verbose(env
, "cannot call GPL-restricted function from non-GPL compatible program\n");
3253 /* With LD_ABS/IND some JITs save/restore skb from r1. */
3254 changes_data
= bpf_helper_changes_pkt_data(fn
->func
);
3255 if (changes_data
&& fn
->arg1_type
!= ARG_PTR_TO_CTX
) {
3256 verbose(env
, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
3257 func_id_name(func_id
), func_id
);
3261 memset(&meta
, 0, sizeof(meta
));
3262 meta
.pkt_access
= fn
->pkt_access
;
3264 err
= check_func_proto(fn
, func_id
);
3266 verbose(env
, "kernel subsystem misconfigured func %s#%d\n",
3267 func_id_name(func_id
), func_id
);
3271 meta
.func_id
= func_id
;
3273 err
= check_func_arg(env
, BPF_REG_1
, fn
->arg1_type
, &meta
);
3276 err
= check_func_arg(env
, BPF_REG_2
, fn
->arg2_type
, &meta
);
3279 err
= check_func_arg(env
, BPF_REG_3
, fn
->arg3_type
, &meta
);
3282 err
= check_func_arg(env
, BPF_REG_4
, fn
->arg4_type
, &meta
);
3285 err
= check_func_arg(env
, BPF_REG_5
, fn
->arg5_type
, &meta
);
3289 err
= record_func_map(env
, &meta
, func_id
, insn_idx
);
3293 /* Mark slots with STACK_MISC in case of raw mode, stack offset
3294 * is inferred from register state.
3296 for (i
= 0; i
< meta
.access_size
; i
++) {
3297 err
= check_mem_access(env
, insn_idx
, meta
.regno
, i
, BPF_B
,
3298 BPF_WRITE
, -1, false);
3303 if (func_id
== BPF_FUNC_tail_call
) {
3304 err
= check_reference_leak(env
);
3306 verbose(env
, "tail_call would lead to reference leak\n");
3309 } else if (is_release_function(func_id
)) {
3310 err
= release_reference(env
, meta
.ref_obj_id
);
3312 verbose(env
, "func %s#%d reference has not been acquired before\n",
3313 func_id_name(func_id
), func_id
);
3318 regs
= cur_regs(env
);
3320 /* check that flags argument in get_local_storage(map, flags) is 0,
3321 * this is required because get_local_storage() can't return an error.
3323 if (func_id
== BPF_FUNC_get_local_storage
&&
3324 !register_is_null(®s
[BPF_REG_2
])) {
3325 verbose(env
, "get_local_storage() doesn't support non-zero flags\n");
3329 /* reset caller saved regs */
3330 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
3331 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
3332 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
3335 /* update return register (already marked as written above) */
3336 if (fn
->ret_type
== RET_INTEGER
) {
3337 /* sets type to SCALAR_VALUE */
3338 mark_reg_unknown(env
, regs
, BPF_REG_0
);
3339 } else if (fn
->ret_type
== RET_VOID
) {
3340 regs
[BPF_REG_0
].type
= NOT_INIT
;
3341 } else if (fn
->ret_type
== RET_PTR_TO_MAP_VALUE_OR_NULL
||
3342 fn
->ret_type
== RET_PTR_TO_MAP_VALUE
) {
3343 /* There is no offset yet applied, variable or fixed */
3344 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
3345 /* remember map_ptr, so that check_map_access()
3346 * can check 'value_size' boundary of memory access
3347 * to map element returned from bpf_map_lookup_elem()
3349 if (meta
.map_ptr
== NULL
) {
3351 "kernel subsystem misconfigured verifier\n");
3354 regs
[BPF_REG_0
].map_ptr
= meta
.map_ptr
;
3355 if (fn
->ret_type
== RET_PTR_TO_MAP_VALUE
) {
3356 regs
[BPF_REG_0
].type
= PTR_TO_MAP_VALUE
;
3357 if (map_value_has_spin_lock(meta
.map_ptr
))
3358 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
3360 regs
[BPF_REG_0
].type
= PTR_TO_MAP_VALUE_OR_NULL
;
3361 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
3363 } else if (fn
->ret_type
== RET_PTR_TO_SOCKET_OR_NULL
) {
3364 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
3365 regs
[BPF_REG_0
].type
= PTR_TO_SOCKET_OR_NULL
;
3366 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
3367 } else if (fn
->ret_type
== RET_PTR_TO_SOCK_COMMON_OR_NULL
) {
3368 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
3369 regs
[BPF_REG_0
].type
= PTR_TO_SOCK_COMMON_OR_NULL
;
3370 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
3371 } else if (fn
->ret_type
== RET_PTR_TO_TCP_SOCK_OR_NULL
) {
3372 mark_reg_known_zero(env
, regs
, BPF_REG_0
);
3373 regs
[BPF_REG_0
].type
= PTR_TO_TCP_SOCK_OR_NULL
;
3374 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
3376 verbose(env
, "unknown return type %d of func %s#%d\n",
3377 fn
->ret_type
, func_id_name(func_id
), func_id
);
3381 if (is_ptr_cast_function(func_id
)) {
3382 /* For release_reference() */
3383 regs
[BPF_REG_0
].ref_obj_id
= meta
.ref_obj_id
;
3384 } else if (is_acquire_function(func_id
)) {
3385 int id
= acquire_reference_state(env
, insn_idx
);
3389 /* For mark_ptr_or_null_reg() */
3390 regs
[BPF_REG_0
].id
= id
;
3391 /* For release_reference() */
3392 regs
[BPF_REG_0
].ref_obj_id
= id
;
3395 do_refine_retval_range(regs
, fn
->ret_type
, func_id
, &meta
);
3397 err
= check_map_func_compatibility(env
, meta
.map_ptr
, func_id
);
3401 if (func_id
== BPF_FUNC_get_stack
&& !env
->prog
->has_callchain_buf
) {
3402 const char *err_str
;
3404 #ifdef CONFIG_PERF_EVENTS
3405 err
= get_callchain_buffers(sysctl_perf_event_max_stack
);
3406 err_str
= "cannot get callchain buffer for func %s#%d\n";
3409 err_str
= "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
3412 verbose(env
, err_str
, func_id_name(func_id
), func_id
);
3416 env
->prog
->has_callchain_buf
= true;
3420 clear_all_pkt_pointers(env
);
3424 static bool signed_add_overflows(s64 a
, s64 b
)
3426 /* Do the add in u64, where overflow is well-defined */
3427 s64 res
= (s64
)((u64
)a
+ (u64
)b
);
3434 static bool signed_sub_overflows(s64 a
, s64 b
)
3436 /* Do the sub in u64, where overflow is well-defined */
3437 s64 res
= (s64
)((u64
)a
- (u64
)b
);
3444 static bool check_reg_sane_offset(struct bpf_verifier_env
*env
,
3445 const struct bpf_reg_state
*reg
,
3446 enum bpf_reg_type type
)
3448 bool known
= tnum_is_const(reg
->var_off
);
3449 s64 val
= reg
->var_off
.value
;
3450 s64 smin
= reg
->smin_value
;
3452 if (known
&& (val
>= BPF_MAX_VAR_OFF
|| val
<= -BPF_MAX_VAR_OFF
)) {
3453 verbose(env
, "math between %s pointer and %lld is not allowed\n",
3454 reg_type_str
[type
], val
);
3458 if (reg
->off
>= BPF_MAX_VAR_OFF
|| reg
->off
<= -BPF_MAX_VAR_OFF
) {
3459 verbose(env
, "%s pointer offset %d is not allowed\n",
3460 reg_type_str
[type
], reg
->off
);
3464 if (smin
== S64_MIN
) {
3465 verbose(env
, "math between %s pointer and register with unbounded min value is not allowed\n",
3466 reg_type_str
[type
]);
3470 if (smin
>= BPF_MAX_VAR_OFF
|| smin
<= -BPF_MAX_VAR_OFF
) {
3471 verbose(env
, "value %lld makes %s pointer be out of bounds\n",
3472 smin
, reg_type_str
[type
]);
3479 static struct bpf_insn_aux_data
*cur_aux(struct bpf_verifier_env
*env
)
3481 return &env
->insn_aux_data
[env
->insn_idx
];
3484 static int retrieve_ptr_limit(const struct bpf_reg_state
*ptr_reg
,
3485 u32
*ptr_limit
, u8 opcode
, bool off_is_neg
)
3487 bool mask_to_left
= (opcode
== BPF_ADD
&& off_is_neg
) ||
3488 (opcode
== BPF_SUB
&& !off_is_neg
);
3491 switch (ptr_reg
->type
) {
3493 /* Indirect variable offset stack access is prohibited in
3494 * unprivileged mode so it's not handled here.
3496 off
= ptr_reg
->off
+ ptr_reg
->var_off
.value
;
3498 *ptr_limit
= MAX_BPF_STACK
+ off
;
3502 case PTR_TO_MAP_VALUE
:
3504 *ptr_limit
= ptr_reg
->umax_value
+ ptr_reg
->off
;
3506 off
= ptr_reg
->smin_value
+ ptr_reg
->off
;
3507 *ptr_limit
= ptr_reg
->map_ptr
->value_size
- off
;
3515 static bool can_skip_alu_sanitation(const struct bpf_verifier_env
*env
,
3516 const struct bpf_insn
*insn
)
3518 return env
->allow_ptr_leaks
|| BPF_SRC(insn
->code
) == BPF_K
;
3521 static int update_alu_sanitation_state(struct bpf_insn_aux_data
*aux
,
3522 u32 alu_state
, u32 alu_limit
)
3524 /* If we arrived here from different branches with different
3525 * state or limits to sanitize, then this won't work.
3527 if (aux
->alu_state
&&
3528 (aux
->alu_state
!= alu_state
||
3529 aux
->alu_limit
!= alu_limit
))
3532 /* Corresponding fixup done in fixup_bpf_calls(). */
3533 aux
->alu_state
= alu_state
;
3534 aux
->alu_limit
= alu_limit
;
3538 static int sanitize_val_alu(struct bpf_verifier_env
*env
,
3539 struct bpf_insn
*insn
)
3541 struct bpf_insn_aux_data
*aux
= cur_aux(env
);
3543 if (can_skip_alu_sanitation(env
, insn
))
3546 return update_alu_sanitation_state(aux
, BPF_ALU_NON_POINTER
, 0);
3549 static int sanitize_ptr_alu(struct bpf_verifier_env
*env
,
3550 struct bpf_insn
*insn
,
3551 const struct bpf_reg_state
*ptr_reg
,
3552 struct bpf_reg_state
*dst_reg
,
3555 struct bpf_verifier_state
*vstate
= env
->cur_state
;
3556 struct bpf_insn_aux_data
*aux
= cur_aux(env
);
3557 bool ptr_is_dst_reg
= ptr_reg
== dst_reg
;
3558 u8 opcode
= BPF_OP(insn
->code
);
3559 u32 alu_state
, alu_limit
;
3560 struct bpf_reg_state tmp
;
3563 if (can_skip_alu_sanitation(env
, insn
))
3566 /* We already marked aux for masking from non-speculative
3567 * paths, thus we got here in the first place. We only care
3568 * to explore bad access from here.
3570 if (vstate
->speculative
)
3573 alu_state
= off_is_neg
? BPF_ALU_NEG_VALUE
: 0;
3574 alu_state
|= ptr_is_dst_reg
?
3575 BPF_ALU_SANITIZE_SRC
: BPF_ALU_SANITIZE_DST
;
3577 if (retrieve_ptr_limit(ptr_reg
, &alu_limit
, opcode
, off_is_neg
))
3579 if (update_alu_sanitation_state(aux
, alu_state
, alu_limit
))
3582 /* Simulate and find potential out-of-bounds access under
3583 * speculative execution from truncation as a result of
3584 * masking when off was not within expected range. If off
3585 * sits in dst, then we temporarily need to move ptr there
3586 * to simulate dst (== 0) +/-= ptr. Needed, for example,
3587 * for cases where we use K-based arithmetic in one direction
3588 * and truncated reg-based in the other in order to explore
3591 if (!ptr_is_dst_reg
) {
3593 *dst_reg
= *ptr_reg
;
3595 ret
= push_stack(env
, env
->insn_idx
+ 1, env
->insn_idx
, true);
3596 if (!ptr_is_dst_reg
&& ret
)
3598 return !ret
? -EFAULT
: 0;
3601 /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
3602 * Caller should also handle BPF_MOV case separately.
3603 * If we return -EACCES, caller may want to try again treating pointer as a
3604 * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks.
3606 static int adjust_ptr_min_max_vals(struct bpf_verifier_env
*env
,
3607 struct bpf_insn
*insn
,
3608 const struct bpf_reg_state
*ptr_reg
,
3609 const struct bpf_reg_state
*off_reg
)
3611 struct bpf_verifier_state
*vstate
= env
->cur_state
;
3612 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
3613 struct bpf_reg_state
*regs
= state
->regs
, *dst_reg
;
3614 bool known
= tnum_is_const(off_reg
->var_off
);
3615 s64 smin_val
= off_reg
->smin_value
, smax_val
= off_reg
->smax_value
,
3616 smin_ptr
= ptr_reg
->smin_value
, smax_ptr
= ptr_reg
->smax_value
;
3617 u64 umin_val
= off_reg
->umin_value
, umax_val
= off_reg
->umax_value
,
3618 umin_ptr
= ptr_reg
->umin_value
, umax_ptr
= ptr_reg
->umax_value
;
3619 u32 dst
= insn
->dst_reg
, src
= insn
->src_reg
;
3620 u8 opcode
= BPF_OP(insn
->code
);
3623 dst_reg
= ®s
[dst
];
3625 if ((known
&& (smin_val
!= smax_val
|| umin_val
!= umax_val
)) ||
3626 smin_val
> smax_val
|| umin_val
> umax_val
) {
3627 /* Taint dst register if offset had invalid bounds derived from
3628 * e.g. dead branches.
3630 __mark_reg_unknown(dst_reg
);
3634 if (BPF_CLASS(insn
->code
) != BPF_ALU64
) {
3635 /* 32-bit ALU ops on pointers produce (meaningless) scalars */
3637 "R%d 32-bit pointer arithmetic prohibited\n",
3642 switch (ptr_reg
->type
) {
3643 case PTR_TO_MAP_VALUE_OR_NULL
:
3644 verbose(env
, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
3645 dst
, reg_type_str
[ptr_reg
->type
]);
3647 case CONST_PTR_TO_MAP
:
3648 case PTR_TO_PACKET_END
:
3650 case PTR_TO_SOCKET_OR_NULL
:
3651 case PTR_TO_SOCK_COMMON
:
3652 case PTR_TO_SOCK_COMMON_OR_NULL
:
3653 case PTR_TO_TCP_SOCK
:
3654 case PTR_TO_TCP_SOCK_OR_NULL
:
3655 verbose(env
, "R%d pointer arithmetic on %s prohibited\n",
3656 dst
, reg_type_str
[ptr_reg
->type
]);
3658 case PTR_TO_MAP_VALUE
:
3659 if (!env
->allow_ptr_leaks
&& !known
&& (smin_val
< 0) != (smax_val
< 0)) {
3660 verbose(env
, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n",
3661 off_reg
== dst_reg
? dst
: src
);
3669 /* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
3670 * The id may be overwritten later if we create a new variable offset.
3672 dst_reg
->type
= ptr_reg
->type
;
3673 dst_reg
->id
= ptr_reg
->id
;
3675 if (!check_reg_sane_offset(env
, off_reg
, ptr_reg
->type
) ||
3676 !check_reg_sane_offset(env
, ptr_reg
, ptr_reg
->type
))
3681 ret
= sanitize_ptr_alu(env
, insn
, ptr_reg
, dst_reg
, smin_val
< 0);
3683 verbose(env
, "R%d tried to add from different maps or paths\n", dst
);
3686 /* We can take a fixed offset as long as it doesn't overflow
3687 * the s32 'off' field
3689 if (known
&& (ptr_reg
->off
+ smin_val
==
3690 (s64
)(s32
)(ptr_reg
->off
+ smin_val
))) {
3691 /* pointer += K. Accumulate it into fixed offset */
3692 dst_reg
->smin_value
= smin_ptr
;
3693 dst_reg
->smax_value
= smax_ptr
;
3694 dst_reg
->umin_value
= umin_ptr
;
3695 dst_reg
->umax_value
= umax_ptr
;
3696 dst_reg
->var_off
= ptr_reg
->var_off
;
3697 dst_reg
->off
= ptr_reg
->off
+ smin_val
;
3698 dst_reg
->raw
= ptr_reg
->raw
;
3701 /* A new variable offset is created. Note that off_reg->off
3702 * == 0, since it's a scalar.
3703 * dst_reg gets the pointer type and since some positive
3704 * integer value was added to the pointer, give it a new 'id'
3705 * if it's a PTR_TO_PACKET.
3706 * this creates a new 'base' pointer, off_reg (variable) gets
3707 * added into the variable offset, and we copy the fixed offset
3710 if (signed_add_overflows(smin_ptr
, smin_val
) ||
3711 signed_add_overflows(smax_ptr
, smax_val
)) {
3712 dst_reg
->smin_value
= S64_MIN
;
3713 dst_reg
->smax_value
= S64_MAX
;
3715 dst_reg
->smin_value
= smin_ptr
+ smin_val
;
3716 dst_reg
->smax_value
= smax_ptr
+ smax_val
;
3718 if (umin_ptr
+ umin_val
< umin_ptr
||
3719 umax_ptr
+ umax_val
< umax_ptr
) {
3720 dst_reg
->umin_value
= 0;
3721 dst_reg
->umax_value
= U64_MAX
;
3723 dst_reg
->umin_value
= umin_ptr
+ umin_val
;
3724 dst_reg
->umax_value
= umax_ptr
+ umax_val
;
3726 dst_reg
->var_off
= tnum_add(ptr_reg
->var_off
, off_reg
->var_off
);
3727 dst_reg
->off
= ptr_reg
->off
;
3728 dst_reg
->raw
= ptr_reg
->raw
;
3729 if (reg_is_pkt_pointer(ptr_reg
)) {
3730 dst_reg
->id
= ++env
->id_gen
;
3731 /* something was added to pkt_ptr, set range to zero */
3736 ret
= sanitize_ptr_alu(env
, insn
, ptr_reg
, dst_reg
, smin_val
< 0);
3738 verbose(env
, "R%d tried to sub from different maps or paths\n", dst
);
3741 if (dst_reg
== off_reg
) {
3742 /* scalar -= pointer. Creates an unknown scalar */
3743 verbose(env
, "R%d tried to subtract pointer from scalar\n",
3747 /* We don't allow subtraction from FP, because (according to
3748 * test_verifier.c test "invalid fp arithmetic", JITs might not
3749 * be able to deal with it.
3751 if (ptr_reg
->type
== PTR_TO_STACK
) {
3752 verbose(env
, "R%d subtraction from stack pointer prohibited\n",
3756 if (known
&& (ptr_reg
->off
- smin_val
==
3757 (s64
)(s32
)(ptr_reg
->off
- smin_val
))) {
3758 /* pointer -= K. Subtract it from fixed offset */
3759 dst_reg
->smin_value
= smin_ptr
;
3760 dst_reg
->smax_value
= smax_ptr
;
3761 dst_reg
->umin_value
= umin_ptr
;
3762 dst_reg
->umax_value
= umax_ptr
;
3763 dst_reg
->var_off
= ptr_reg
->var_off
;
3764 dst_reg
->id
= ptr_reg
->id
;
3765 dst_reg
->off
= ptr_reg
->off
- smin_val
;
3766 dst_reg
->raw
= ptr_reg
->raw
;
3769 /* A new variable offset is created. If the subtrahend is known
3770 * nonnegative, then any reg->range we had before is still good.
3772 if (signed_sub_overflows(smin_ptr
, smax_val
) ||
3773 signed_sub_overflows(smax_ptr
, smin_val
)) {
3774 /* Overflow possible, we know nothing */
3775 dst_reg
->smin_value
= S64_MIN
;
3776 dst_reg
->smax_value
= S64_MAX
;
3778 dst_reg
->smin_value
= smin_ptr
- smax_val
;
3779 dst_reg
->smax_value
= smax_ptr
- smin_val
;
3781 if (umin_ptr
< umax_val
) {
3782 /* Overflow possible, we know nothing */
3783 dst_reg
->umin_value
= 0;
3784 dst_reg
->umax_value
= U64_MAX
;
3786 /* Cannot overflow (as long as bounds are consistent) */
3787 dst_reg
->umin_value
= umin_ptr
- umax_val
;
3788 dst_reg
->umax_value
= umax_ptr
- umin_val
;
3790 dst_reg
->var_off
= tnum_sub(ptr_reg
->var_off
, off_reg
->var_off
);
3791 dst_reg
->off
= ptr_reg
->off
;
3792 dst_reg
->raw
= ptr_reg
->raw
;
3793 if (reg_is_pkt_pointer(ptr_reg
)) {
3794 dst_reg
->id
= ++env
->id_gen
;
3795 /* something was added to pkt_ptr, set range to zero */
3803 /* bitwise ops on pointers are troublesome, prohibit. */
3804 verbose(env
, "R%d bitwise operator %s on pointer prohibited\n",
3805 dst
, bpf_alu_string
[opcode
>> 4]);
3808 /* other operators (e.g. MUL,LSH) produce non-pointer results */
3809 verbose(env
, "R%d pointer arithmetic with %s operator prohibited\n",
3810 dst
, bpf_alu_string
[opcode
>> 4]);
3814 if (!check_reg_sane_offset(env
, dst_reg
, ptr_reg
->type
))
3817 __update_reg_bounds(dst_reg
);
3818 __reg_deduce_bounds(dst_reg
);
3819 __reg_bound_offset(dst_reg
);
3821 /* For unprivileged we require that resulting offset must be in bounds
3822 * in order to be able to sanitize access later on.
3824 if (!env
->allow_ptr_leaks
) {
3825 if (dst_reg
->type
== PTR_TO_MAP_VALUE
&&
3826 check_map_access(env
, dst
, dst_reg
->off
, 1, false)) {
3827 verbose(env
, "R%d pointer arithmetic of map value goes out of range, "
3828 "prohibited for !root\n", dst
);
3830 } else if (dst_reg
->type
== PTR_TO_STACK
&&
3831 check_stack_access(env
, dst_reg
, dst_reg
->off
+
3832 dst_reg
->var_off
.value
, 1)) {
3833 verbose(env
, "R%d stack pointer arithmetic goes out of range, "
3834 "prohibited for !root\n", dst
);
3842 /* WARNING: This function does calculations on 64-bit values, but the actual
3843 * execution may occur on 32-bit values. Therefore, things like bitshifts
3844 * need extra checks in the 32-bit case.
3846 static int adjust_scalar_min_max_vals(struct bpf_verifier_env
*env
,
3847 struct bpf_insn
*insn
,
3848 struct bpf_reg_state
*dst_reg
,
3849 struct bpf_reg_state src_reg
)
3851 struct bpf_reg_state
*regs
= cur_regs(env
);
3852 u8 opcode
= BPF_OP(insn
->code
);
3853 bool src_known
, dst_known
;
3854 s64 smin_val
, smax_val
;
3855 u64 umin_val
, umax_val
;
3856 u64 insn_bitness
= (BPF_CLASS(insn
->code
) == BPF_ALU64
) ? 64 : 32;
3857 u32 dst
= insn
->dst_reg
;
3860 if (insn_bitness
== 32) {
3861 /* Relevant for 32-bit RSH: Information can propagate towards
3862 * LSB, so it isn't sufficient to only truncate the output to
3865 coerce_reg_to_size(dst_reg
, 4);
3866 coerce_reg_to_size(&src_reg
, 4);
3869 smin_val
= src_reg
.smin_value
;
3870 smax_val
= src_reg
.smax_value
;
3871 umin_val
= src_reg
.umin_value
;
3872 umax_val
= src_reg
.umax_value
;
3873 src_known
= tnum_is_const(src_reg
.var_off
);
3874 dst_known
= tnum_is_const(dst_reg
->var_off
);
3876 if ((src_known
&& (smin_val
!= smax_val
|| umin_val
!= umax_val
)) ||
3877 smin_val
> smax_val
|| umin_val
> umax_val
) {
3878 /* Taint dst register if offset had invalid bounds derived from
3879 * e.g. dead branches.
3881 __mark_reg_unknown(dst_reg
);
3886 opcode
!= BPF_ADD
&& opcode
!= BPF_SUB
&& opcode
!= BPF_AND
) {
3887 __mark_reg_unknown(dst_reg
);
3893 ret
= sanitize_val_alu(env
, insn
);
3895 verbose(env
, "R%d tried to add from different pointers or scalars\n", dst
);
3898 if (signed_add_overflows(dst_reg
->smin_value
, smin_val
) ||
3899 signed_add_overflows(dst_reg
->smax_value
, smax_val
)) {
3900 dst_reg
->smin_value
= S64_MIN
;
3901 dst_reg
->smax_value
= S64_MAX
;
3903 dst_reg
->smin_value
+= smin_val
;
3904 dst_reg
->smax_value
+= smax_val
;
3906 if (dst_reg
->umin_value
+ umin_val
< umin_val
||
3907 dst_reg
->umax_value
+ umax_val
< umax_val
) {
3908 dst_reg
->umin_value
= 0;
3909 dst_reg
->umax_value
= U64_MAX
;
3911 dst_reg
->umin_value
+= umin_val
;
3912 dst_reg
->umax_value
+= umax_val
;
3914 dst_reg
->var_off
= tnum_add(dst_reg
->var_off
, src_reg
.var_off
);
3917 ret
= sanitize_val_alu(env
, insn
);
3919 verbose(env
, "R%d tried to sub from different pointers or scalars\n", dst
);
3922 if (signed_sub_overflows(dst_reg
->smin_value
, smax_val
) ||
3923 signed_sub_overflows(dst_reg
->smax_value
, smin_val
)) {
3924 /* Overflow possible, we know nothing */
3925 dst_reg
->smin_value
= S64_MIN
;
3926 dst_reg
->smax_value
= S64_MAX
;
3928 dst_reg
->smin_value
-= smax_val
;
3929 dst_reg
->smax_value
-= smin_val
;
3931 if (dst_reg
->umin_value
< umax_val
) {
3932 /* Overflow possible, we know nothing */
3933 dst_reg
->umin_value
= 0;
3934 dst_reg
->umax_value
= U64_MAX
;
3936 /* Cannot overflow (as long as bounds are consistent) */
3937 dst_reg
->umin_value
-= umax_val
;
3938 dst_reg
->umax_value
-= umin_val
;
3940 dst_reg
->var_off
= tnum_sub(dst_reg
->var_off
, src_reg
.var_off
);
3943 dst_reg
->var_off
= tnum_mul(dst_reg
->var_off
, src_reg
.var_off
);
3944 if (smin_val
< 0 || dst_reg
->smin_value
< 0) {
3945 /* Ain't nobody got time to multiply that sign */
3946 __mark_reg_unbounded(dst_reg
);
3947 __update_reg_bounds(dst_reg
);
3950 /* Both values are positive, so we can work with unsigned and
3951 * copy the result to signed (unless it exceeds S64_MAX).
3953 if (umax_val
> U32_MAX
|| dst_reg
->umax_value
> U32_MAX
) {
3954 /* Potential overflow, we know nothing */
3955 __mark_reg_unbounded(dst_reg
);
3956 /* (except what we can learn from the var_off) */
3957 __update_reg_bounds(dst_reg
);
3960 dst_reg
->umin_value
*= umin_val
;
3961 dst_reg
->umax_value
*= umax_val
;
3962 if (dst_reg
->umax_value
> S64_MAX
) {
3963 /* Overflow possible, we know nothing */
3964 dst_reg
->smin_value
= S64_MIN
;
3965 dst_reg
->smax_value
= S64_MAX
;
3967 dst_reg
->smin_value
= dst_reg
->umin_value
;
3968 dst_reg
->smax_value
= dst_reg
->umax_value
;
3972 if (src_known
&& dst_known
) {
3973 __mark_reg_known(dst_reg
, dst_reg
->var_off
.value
&
3974 src_reg
.var_off
.value
);
3977 /* We get our minimum from the var_off, since that's inherently
3978 * bitwise. Our maximum is the minimum of the operands' maxima.
3980 dst_reg
->var_off
= tnum_and(dst_reg
->var_off
, src_reg
.var_off
);
3981 dst_reg
->umin_value
= dst_reg
->var_off
.value
;
3982 dst_reg
->umax_value
= min(dst_reg
->umax_value
, umax_val
);
3983 if (dst_reg
->smin_value
< 0 || smin_val
< 0) {
3984 /* Lose signed bounds when ANDing negative numbers,
3985 * ain't nobody got time for that.
3987 dst_reg
->smin_value
= S64_MIN
;
3988 dst_reg
->smax_value
= S64_MAX
;
3990 /* ANDing two positives gives a positive, so safe to
3991 * cast result into s64.
3993 dst_reg
->smin_value
= dst_reg
->umin_value
;
3994 dst_reg
->smax_value
= dst_reg
->umax_value
;
3996 /* We may learn something more from the var_off */
3997 __update_reg_bounds(dst_reg
);
4000 if (src_known
&& dst_known
) {
4001 __mark_reg_known(dst_reg
, dst_reg
->var_off
.value
|
4002 src_reg
.var_off
.value
);
4005 /* We get our maximum from the var_off, and our minimum is the
4006 * maximum of the operands' minima
4008 dst_reg
->var_off
= tnum_or(dst_reg
->var_off
, src_reg
.var_off
);
4009 dst_reg
->umin_value
= max(dst_reg
->umin_value
, umin_val
);
4010 dst_reg
->umax_value
= dst_reg
->var_off
.value
|
4011 dst_reg
->var_off
.mask
;
4012 if (dst_reg
->smin_value
< 0 || smin_val
< 0) {
4013 /* Lose signed bounds when ORing negative numbers,
4014 * ain't nobody got time for that.
4016 dst_reg
->smin_value
= S64_MIN
;
4017 dst_reg
->smax_value
= S64_MAX
;
4019 /* ORing two positives gives a positive, so safe to
4020 * cast result into s64.
4022 dst_reg
->smin_value
= dst_reg
->umin_value
;
4023 dst_reg
->smax_value
= dst_reg
->umax_value
;
4025 /* We may learn something more from the var_off */
4026 __update_reg_bounds(dst_reg
);
4029 if (umax_val
>= insn_bitness
) {
4030 /* Shifts greater than 31 or 63 are undefined.
4031 * This includes shifts by a negative number.
4033 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
4036 /* We lose all sign bit information (except what we can pick
4039 dst_reg
->smin_value
= S64_MIN
;
4040 dst_reg
->smax_value
= S64_MAX
;
4041 /* If we might shift our top bit out, then we know nothing */
4042 if (dst_reg
->umax_value
> 1ULL << (63 - umax_val
)) {
4043 dst_reg
->umin_value
= 0;
4044 dst_reg
->umax_value
= U64_MAX
;
4046 dst_reg
->umin_value
<<= umin_val
;
4047 dst_reg
->umax_value
<<= umax_val
;
4049 dst_reg
->var_off
= tnum_lshift(dst_reg
->var_off
, umin_val
);
4050 /* We may learn something more from the var_off */
4051 __update_reg_bounds(dst_reg
);
4054 if (umax_val
>= insn_bitness
) {
4055 /* Shifts greater than 31 or 63 are undefined.
4056 * This includes shifts by a negative number.
4058 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
4061 /* BPF_RSH is an unsigned shift. If the value in dst_reg might
4062 * be negative, then either:
4063 * 1) src_reg might be zero, so the sign bit of the result is
4064 * unknown, so we lose our signed bounds
4065 * 2) it's known negative, thus the unsigned bounds capture the
4067 * 3) the signed bounds cross zero, so they tell us nothing
4069 * If the value in dst_reg is known nonnegative, then again the
4070 * unsigned bounts capture the signed bounds.
4071 * Thus, in all cases it suffices to blow away our signed bounds
4072 * and rely on inferring new ones from the unsigned bounds and
4073 * var_off of the result.
4075 dst_reg
->smin_value
= S64_MIN
;
4076 dst_reg
->smax_value
= S64_MAX
;
4077 dst_reg
->var_off
= tnum_rshift(dst_reg
->var_off
, umin_val
);
4078 dst_reg
->umin_value
>>= umax_val
;
4079 dst_reg
->umax_value
>>= umin_val
;
4080 /* We may learn something more from the var_off */
4081 __update_reg_bounds(dst_reg
);
4084 if (umax_val
>= insn_bitness
) {
4085 /* Shifts greater than 31 or 63 are undefined.
4086 * This includes shifts by a negative number.
4088 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
4092 /* Upon reaching here, src_known is true and
4093 * umax_val is equal to umin_val.
4095 dst_reg
->smin_value
>>= umin_val
;
4096 dst_reg
->smax_value
>>= umin_val
;
4097 dst_reg
->var_off
= tnum_arshift(dst_reg
->var_off
, umin_val
);
4099 /* blow away the dst_reg umin_value/umax_value and rely on
4100 * dst_reg var_off to refine the result.
4102 dst_reg
->umin_value
= 0;
4103 dst_reg
->umax_value
= U64_MAX
;
4104 __update_reg_bounds(dst_reg
);
4107 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
4111 if (BPF_CLASS(insn
->code
) != BPF_ALU64
) {
4112 /* 32-bit ALU ops are (32,32)->32 */
4113 coerce_reg_to_size(dst_reg
, 4);
4116 __reg_deduce_bounds(dst_reg
);
4117 __reg_bound_offset(dst_reg
);
4121 /* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max
4124 static int adjust_reg_min_max_vals(struct bpf_verifier_env
*env
,
4125 struct bpf_insn
*insn
)
4127 struct bpf_verifier_state
*vstate
= env
->cur_state
;
4128 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
4129 struct bpf_reg_state
*regs
= state
->regs
, *dst_reg
, *src_reg
;
4130 struct bpf_reg_state
*ptr_reg
= NULL
, off_reg
= {0};
4131 u8 opcode
= BPF_OP(insn
->code
);
4133 dst_reg
= ®s
[insn
->dst_reg
];
4135 if (dst_reg
->type
!= SCALAR_VALUE
)
4137 if (BPF_SRC(insn
->code
) == BPF_X
) {
4138 src_reg
= ®s
[insn
->src_reg
];
4139 if (src_reg
->type
!= SCALAR_VALUE
) {
4140 if (dst_reg
->type
!= SCALAR_VALUE
) {
4141 /* Combining two pointers by any ALU op yields
4142 * an arbitrary scalar. Disallow all math except
4143 * pointer subtraction
4145 if (opcode
== BPF_SUB
&& env
->allow_ptr_leaks
) {
4146 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
4149 verbose(env
, "R%d pointer %s pointer prohibited\n",
4151 bpf_alu_string
[opcode
>> 4]);
4154 /* scalar += pointer
4155 * This is legal, but we have to reverse our
4156 * src/dest handling in computing the range
4158 return adjust_ptr_min_max_vals(env
, insn
,
4161 } else if (ptr_reg
) {
4162 /* pointer += scalar */
4163 return adjust_ptr_min_max_vals(env
, insn
,
4167 /* Pretend the src is a reg with a known value, since we only
4168 * need to be able to read from this state.
4170 off_reg
.type
= SCALAR_VALUE
;
4171 __mark_reg_known(&off_reg
, insn
->imm
);
4173 if (ptr_reg
) /* pointer += K */
4174 return adjust_ptr_min_max_vals(env
, insn
,
4178 /* Got here implies adding two SCALAR_VALUEs */
4179 if (WARN_ON_ONCE(ptr_reg
)) {
4180 print_verifier_state(env
, state
);
4181 verbose(env
, "verifier internal error: unexpected ptr_reg\n");
4184 if (WARN_ON(!src_reg
)) {
4185 print_verifier_state(env
, state
);
4186 verbose(env
, "verifier internal error: no src_reg\n");
4189 return adjust_scalar_min_max_vals(env
, insn
, dst_reg
, *src_reg
);
4192 /* check validity of 32-bit and 64-bit arithmetic operations */
4193 static int check_alu_op(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
4195 struct bpf_reg_state
*regs
= cur_regs(env
);
4196 u8 opcode
= BPF_OP(insn
->code
);
4199 if (opcode
== BPF_END
|| opcode
== BPF_NEG
) {
4200 if (opcode
== BPF_NEG
) {
4201 if (BPF_SRC(insn
->code
) != 0 ||
4202 insn
->src_reg
!= BPF_REG_0
||
4203 insn
->off
!= 0 || insn
->imm
!= 0) {
4204 verbose(env
, "BPF_NEG uses reserved fields\n");
4208 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0 ||
4209 (insn
->imm
!= 16 && insn
->imm
!= 32 && insn
->imm
!= 64) ||
4210 BPF_CLASS(insn
->code
) == BPF_ALU64
) {
4211 verbose(env
, "BPF_END uses reserved fields\n");
4216 /* check src operand */
4217 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
4221 if (is_pointer_value(env
, insn
->dst_reg
)) {
4222 verbose(env
, "R%d pointer arithmetic prohibited\n",
4227 /* check dest operand */
4228 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP
);
4232 } else if (opcode
== BPF_MOV
) {
4234 if (BPF_SRC(insn
->code
) == BPF_X
) {
4235 if (insn
->imm
!= 0 || insn
->off
!= 0) {
4236 verbose(env
, "BPF_MOV uses reserved fields\n");
4240 /* check src operand */
4241 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
4245 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0) {
4246 verbose(env
, "BPF_MOV uses reserved fields\n");
4251 /* check dest operand, mark as required later */
4252 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
4256 if (BPF_SRC(insn
->code
) == BPF_X
) {
4257 struct bpf_reg_state
*src_reg
= regs
+ insn
->src_reg
;
4258 struct bpf_reg_state
*dst_reg
= regs
+ insn
->dst_reg
;
4260 if (BPF_CLASS(insn
->code
) == BPF_ALU64
) {
4262 * copy register state to dest reg
4264 *dst_reg
= *src_reg
;
4265 dst_reg
->live
|= REG_LIVE_WRITTEN
;
4268 if (is_pointer_value(env
, insn
->src_reg
)) {
4270 "R%d partial copy of pointer\n",
4273 } else if (src_reg
->type
== SCALAR_VALUE
) {
4274 *dst_reg
= *src_reg
;
4275 dst_reg
->live
|= REG_LIVE_WRITTEN
;
4277 mark_reg_unknown(env
, regs
,
4280 coerce_reg_to_size(dst_reg
, 4);
4284 * remember the value we stored into this reg
4286 /* clear any state __mark_reg_known doesn't set */
4287 mark_reg_unknown(env
, regs
, insn
->dst_reg
);
4288 regs
[insn
->dst_reg
].type
= SCALAR_VALUE
;
4289 if (BPF_CLASS(insn
->code
) == BPF_ALU64
) {
4290 __mark_reg_known(regs
+ insn
->dst_reg
,
4293 __mark_reg_known(regs
+ insn
->dst_reg
,
4298 } else if (opcode
> BPF_END
) {
4299 verbose(env
, "invalid BPF_ALU opcode %x\n", opcode
);
4302 } else { /* all other ALU ops: and, sub, xor, add, ... */
4304 if (BPF_SRC(insn
->code
) == BPF_X
) {
4305 if (insn
->imm
!= 0 || insn
->off
!= 0) {
4306 verbose(env
, "BPF_ALU uses reserved fields\n");
4309 /* check src1 operand */
4310 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
4314 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0) {
4315 verbose(env
, "BPF_ALU uses reserved fields\n");
4320 /* check src2 operand */
4321 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
4325 if ((opcode
== BPF_MOD
|| opcode
== BPF_DIV
) &&
4326 BPF_SRC(insn
->code
) == BPF_K
&& insn
->imm
== 0) {
4327 verbose(env
, "div by zero\n");
4331 if ((opcode
== BPF_LSH
|| opcode
== BPF_RSH
||
4332 opcode
== BPF_ARSH
) && BPF_SRC(insn
->code
) == BPF_K
) {
4333 int size
= BPF_CLASS(insn
->code
) == BPF_ALU64
? 64 : 32;
4335 if (insn
->imm
< 0 || insn
->imm
>= size
) {
4336 verbose(env
, "invalid shift %d\n", insn
->imm
);
4341 /* check dest operand */
4342 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
4346 return adjust_reg_min_max_vals(env
, insn
);
4352 static void __find_good_pkt_pointers(struct bpf_func_state
*state
,
4353 struct bpf_reg_state
*dst_reg
,
4354 enum bpf_reg_type type
, u16 new_range
)
4356 struct bpf_reg_state
*reg
;
4359 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
4360 reg
= &state
->regs
[i
];
4361 if (reg
->type
== type
&& reg
->id
== dst_reg
->id
)
4362 /* keep the maximum range already checked */
4363 reg
->range
= max(reg
->range
, new_range
);
4366 bpf_for_each_spilled_reg(i
, state
, reg
) {
4369 if (reg
->type
== type
&& reg
->id
== dst_reg
->id
)
4370 reg
->range
= max(reg
->range
, new_range
);
4374 static void find_good_pkt_pointers(struct bpf_verifier_state
*vstate
,
4375 struct bpf_reg_state
*dst_reg
,
4376 enum bpf_reg_type type
,
4377 bool range_right_open
)
4382 if (dst_reg
->off
< 0 ||
4383 (dst_reg
->off
== 0 && range_right_open
))
4384 /* This doesn't give us any range */
4387 if (dst_reg
->umax_value
> MAX_PACKET_OFF
||
4388 dst_reg
->umax_value
+ dst_reg
->off
> MAX_PACKET_OFF
)
4389 /* Risk of overflow. For instance, ptr + (1<<63) may be less
4390 * than pkt_end, but that's because it's also less than pkt.
4394 new_range
= dst_reg
->off
;
4395 if (range_right_open
)
4398 /* Examples for register markings:
4400 * pkt_data in dst register:
4404 * if (r2 > pkt_end) goto <handle exception>
4409 * if (r2 < pkt_end) goto <access okay>
4410 * <handle exception>
4413 * r2 == dst_reg, pkt_end == src_reg
4414 * r2=pkt(id=n,off=8,r=0)
4415 * r3=pkt(id=n,off=0,r=0)
4417 * pkt_data in src register:
4421 * if (pkt_end >= r2) goto <access okay>
4422 * <handle exception>
4426 * if (pkt_end <= r2) goto <handle exception>
4430 * pkt_end == dst_reg, r2 == src_reg
4431 * r2=pkt(id=n,off=8,r=0)
4432 * r3=pkt(id=n,off=0,r=0)
4434 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
4435 * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
4436 * and [r3, r3 + 8-1) respectively is safe to access depending on
4440 /* If our ids match, then we must have the same max_value. And we
4441 * don't care about the other reg's fixed offset, since if it's too big
4442 * the range won't allow anything.
4443 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
4445 for (i
= 0; i
<= vstate
->curframe
; i
++)
4446 __find_good_pkt_pointers(vstate
->frame
[i
], dst_reg
, type
,
4450 /* compute branch direction of the expression "if (reg opcode val) goto target;"
4452 * 1 - branch will be taken and "goto target" will be executed
4453 * 0 - branch will not be taken and fall-through to next insn
4454 * -1 - unknown. Example: "if (reg < 5)" is unknown when register value range [0,10]
4456 static int is_branch_taken(struct bpf_reg_state
*reg
, u64 val
, u8 opcode
,
4459 struct bpf_reg_state reg_lo
;
4462 if (__is_pointer_value(false, reg
))
4468 /* For JMP32, only low 32 bits are compared, coerce_reg_to_size
4469 * could truncate high bits and update umin/umax according to
4470 * information of low bits.
4472 coerce_reg_to_size(reg
, 4);
4473 /* smin/smax need special handling. For example, after coerce,
4474 * if smin_value is 0x00000000ffffffffLL, the value is -1 when
4475 * used as operand to JMP32. It is a negative number from s32's
4476 * point of view, while it is a positive number when seen as
4477 * s64. The smin/smax are kept as s64, therefore, when used with
4478 * JMP32, they need to be transformed into s32, then sign
4479 * extended back to s64.
4481 * Also, smin/smax were copied from umin/umax. If umin/umax has
4482 * different sign bit, then min/max relationship doesn't
4483 * maintain after casting into s32, for this case, set smin/smax
4486 if ((reg
->umax_value
^ reg
->umin_value
) &
4488 reg
->smin_value
= S32_MIN
;
4489 reg
->smax_value
= S32_MAX
;
4491 reg
->smin_value
= (s64
)(s32
)reg
->smin_value
;
4492 reg
->smax_value
= (s64
)(s32
)reg
->smax_value
;
4495 sval
= (s64
)(s32
)val
;
4502 if (tnum_is_const(reg
->var_off
))
4503 return !!tnum_equals_const(reg
->var_off
, val
);
4506 if (tnum_is_const(reg
->var_off
))
4507 return !tnum_equals_const(reg
->var_off
, val
);
4510 if ((~reg
->var_off
.mask
& reg
->var_off
.value
) & val
)
4512 if (!((reg
->var_off
.mask
| reg
->var_off
.value
) & val
))
4516 if (reg
->umin_value
> val
)
4518 else if (reg
->umax_value
<= val
)
4522 if (reg
->smin_value
> sval
)
4524 else if (reg
->smax_value
< sval
)
4528 if (reg
->umax_value
< val
)
4530 else if (reg
->umin_value
>= val
)
4534 if (reg
->smax_value
< sval
)
4536 else if (reg
->smin_value
>= sval
)
4540 if (reg
->umin_value
>= val
)
4542 else if (reg
->umax_value
< val
)
4546 if (reg
->smin_value
>= sval
)
4548 else if (reg
->smax_value
< sval
)
4552 if (reg
->umax_value
<= val
)
4554 else if (reg
->umin_value
> val
)
4558 if (reg
->smax_value
<= sval
)
4560 else if (reg
->smin_value
> sval
)
4568 /* Generate min value of the high 32-bit from TNUM info. */
4569 static u64
gen_hi_min(struct tnum var
)
4571 return var
.value
& ~0xffffffffULL
;
4574 /* Generate max value of the high 32-bit from TNUM info. */
4575 static u64
gen_hi_max(struct tnum var
)
4577 return (var
.value
| var
.mask
) & ~0xffffffffULL
;
4580 /* Return true if VAL is compared with a s64 sign extended from s32, and they
4581 * are with the same signedness.
4583 static bool cmp_val_with_extended_s64(s64 sval
, struct bpf_reg_state
*reg
)
4585 return ((s32
)sval
>= 0 &&
4586 reg
->smin_value
>= 0 && reg
->smax_value
<= S32_MAX
) ||
4588 reg
->smax_value
<= 0 && reg
->smin_value
>= S32_MIN
);
4591 /* Adjusts the register min/max values in the case that the dst_reg is the
4592 * variable register that we are working on, and src_reg is a constant or we're
4593 * simply doing a BPF_K check.
4594 * In JEQ/JNE cases we also adjust the var_off values.
4596 static void reg_set_min_max(struct bpf_reg_state
*true_reg
,
4597 struct bpf_reg_state
*false_reg
, u64 val
,
4598 u8 opcode
, bool is_jmp32
)
4602 /* If the dst_reg is a pointer, we can't learn anything about its
4603 * variable offset from the compare (unless src_reg were a pointer into
4604 * the same object, but we don't bother with that.
4605 * Since false_reg and true_reg have the same type by construction, we
4606 * only need to check one of them for pointerness.
4608 if (__is_pointer_value(false, false_reg
))
4611 val
= is_jmp32
? (u32
)val
: val
;
4612 sval
= is_jmp32
? (s64
)(s32
)val
: (s64
)val
;
4618 struct bpf_reg_state
*reg
=
4619 opcode
== BPF_JEQ
? true_reg
: false_reg
;
4621 /* For BPF_JEQ, if this is false we know nothing Jon Snow, but
4622 * if it is true we know the value for sure. Likewise for
4626 u64 old_v
= reg
->var_off
.value
;
4627 u64 hi_mask
= ~0xffffffffULL
;
4629 reg
->var_off
.value
= (old_v
& hi_mask
) | val
;
4630 reg
->var_off
.mask
&= hi_mask
;
4632 __mark_reg_known(reg
, val
);
4637 false_reg
->var_off
= tnum_and(false_reg
->var_off
,
4639 if (is_power_of_2(val
))
4640 true_reg
->var_off
= tnum_or(true_reg
->var_off
,
4646 u64 false_umax
= opcode
== BPF_JGT
? val
: val
- 1;
4647 u64 true_umin
= opcode
== BPF_JGT
? val
+ 1 : val
;
4650 false_umax
+= gen_hi_max(false_reg
->var_off
);
4651 true_umin
+= gen_hi_min(true_reg
->var_off
);
4653 false_reg
->umax_value
= min(false_reg
->umax_value
, false_umax
);
4654 true_reg
->umin_value
= max(true_reg
->umin_value
, true_umin
);
4660 s64 false_smax
= opcode
== BPF_JSGT
? sval
: sval
- 1;
4661 s64 true_smin
= opcode
== BPF_JSGT
? sval
+ 1 : sval
;
4663 /* If the full s64 was not sign-extended from s32 then don't
4664 * deduct further info.
4666 if (is_jmp32
&& !cmp_val_with_extended_s64(sval
, false_reg
))
4668 false_reg
->smax_value
= min(false_reg
->smax_value
, false_smax
);
4669 true_reg
->smin_value
= max(true_reg
->smin_value
, true_smin
);
4675 u64 false_umin
= opcode
== BPF_JLT
? val
: val
+ 1;
4676 u64 true_umax
= opcode
== BPF_JLT
? val
- 1 : val
;
4679 false_umin
+= gen_hi_min(false_reg
->var_off
);
4680 true_umax
+= gen_hi_max(true_reg
->var_off
);
4682 false_reg
->umin_value
= max(false_reg
->umin_value
, false_umin
);
4683 true_reg
->umax_value
= min(true_reg
->umax_value
, true_umax
);
4689 s64 false_smin
= opcode
== BPF_JSLT
? sval
: sval
+ 1;
4690 s64 true_smax
= opcode
== BPF_JSLT
? sval
- 1 : sval
;
4692 if (is_jmp32
&& !cmp_val_with_extended_s64(sval
, false_reg
))
4694 false_reg
->smin_value
= max(false_reg
->smin_value
, false_smin
);
4695 true_reg
->smax_value
= min(true_reg
->smax_value
, true_smax
);
4702 __reg_deduce_bounds(false_reg
);
4703 __reg_deduce_bounds(true_reg
);
4704 /* We might have learned some bits from the bounds. */
4705 __reg_bound_offset(false_reg
);
4706 __reg_bound_offset(true_reg
);
4707 /* Intersecting with the old var_off might have improved our bounds
4708 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
4709 * then new var_off is (0; 0x7f...fc) which improves our umax.
4711 __update_reg_bounds(false_reg
);
4712 __update_reg_bounds(true_reg
);
4715 /* Same as above, but for the case that dst_reg holds a constant and src_reg is
4718 static void reg_set_min_max_inv(struct bpf_reg_state
*true_reg
,
4719 struct bpf_reg_state
*false_reg
, u64 val
,
4720 u8 opcode
, bool is_jmp32
)
4724 if (__is_pointer_value(false, false_reg
))
4727 val
= is_jmp32
? (u32
)val
: val
;
4728 sval
= is_jmp32
? (s64
)(s32
)val
: (s64
)val
;
4734 struct bpf_reg_state
*reg
=
4735 opcode
== BPF_JEQ
? true_reg
: false_reg
;
4738 u64 old_v
= reg
->var_off
.value
;
4739 u64 hi_mask
= ~0xffffffffULL
;
4741 reg
->var_off
.value
= (old_v
& hi_mask
) | val
;
4742 reg
->var_off
.mask
&= hi_mask
;
4744 __mark_reg_known(reg
, val
);
4749 false_reg
->var_off
= tnum_and(false_reg
->var_off
,
4751 if (is_power_of_2(val
))
4752 true_reg
->var_off
= tnum_or(true_reg
->var_off
,
4758 u64 false_umin
= opcode
== BPF_JGT
? val
: val
+ 1;
4759 u64 true_umax
= opcode
== BPF_JGT
? val
- 1 : val
;
4762 false_umin
+= gen_hi_min(false_reg
->var_off
);
4763 true_umax
+= gen_hi_max(true_reg
->var_off
);
4765 false_reg
->umin_value
= max(false_reg
->umin_value
, false_umin
);
4766 true_reg
->umax_value
= min(true_reg
->umax_value
, true_umax
);
4772 s64 false_smin
= opcode
== BPF_JSGT
? sval
: sval
+ 1;
4773 s64 true_smax
= opcode
== BPF_JSGT
? sval
- 1 : sval
;
4775 if (is_jmp32
&& !cmp_val_with_extended_s64(sval
, false_reg
))
4777 false_reg
->smin_value
= max(false_reg
->smin_value
, false_smin
);
4778 true_reg
->smax_value
= min(true_reg
->smax_value
, true_smax
);
4784 u64 false_umax
= opcode
== BPF_JLT
? val
: val
- 1;
4785 u64 true_umin
= opcode
== BPF_JLT
? val
+ 1 : val
;
4788 false_umax
+= gen_hi_max(false_reg
->var_off
);
4789 true_umin
+= gen_hi_min(true_reg
->var_off
);
4791 false_reg
->umax_value
= min(false_reg
->umax_value
, false_umax
);
4792 true_reg
->umin_value
= max(true_reg
->umin_value
, true_umin
);
4798 s64 false_smax
= opcode
== BPF_JSLT
? sval
: sval
- 1;
4799 s64 true_smin
= opcode
== BPF_JSLT
? sval
+ 1 : sval
;
4801 if (is_jmp32
&& !cmp_val_with_extended_s64(sval
, false_reg
))
4803 false_reg
->smax_value
= min(false_reg
->smax_value
, false_smax
);
4804 true_reg
->smin_value
= max(true_reg
->smin_value
, true_smin
);
4811 __reg_deduce_bounds(false_reg
);
4812 __reg_deduce_bounds(true_reg
);
4813 /* We might have learned some bits from the bounds. */
4814 __reg_bound_offset(false_reg
);
4815 __reg_bound_offset(true_reg
);
4816 /* Intersecting with the old var_off might have improved our bounds
4817 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
4818 * then new var_off is (0; 0x7f...fc) which improves our umax.
4820 __update_reg_bounds(false_reg
);
4821 __update_reg_bounds(true_reg
);
4824 /* Regs are known to be equal, so intersect their min/max/var_off */
4825 static void __reg_combine_min_max(struct bpf_reg_state
*src_reg
,
4826 struct bpf_reg_state
*dst_reg
)
4828 src_reg
->umin_value
= dst_reg
->umin_value
= max(src_reg
->umin_value
,
4829 dst_reg
->umin_value
);
4830 src_reg
->umax_value
= dst_reg
->umax_value
= min(src_reg
->umax_value
,
4831 dst_reg
->umax_value
);
4832 src_reg
->smin_value
= dst_reg
->smin_value
= max(src_reg
->smin_value
,
4833 dst_reg
->smin_value
);
4834 src_reg
->smax_value
= dst_reg
->smax_value
= min(src_reg
->smax_value
,
4835 dst_reg
->smax_value
);
4836 src_reg
->var_off
= dst_reg
->var_off
= tnum_intersect(src_reg
->var_off
,
4838 /* We might have learned new bounds from the var_off. */
4839 __update_reg_bounds(src_reg
);
4840 __update_reg_bounds(dst_reg
);
4841 /* We might have learned something about the sign bit. */
4842 __reg_deduce_bounds(src_reg
);
4843 __reg_deduce_bounds(dst_reg
);
4844 /* We might have learned some bits from the bounds. */
4845 __reg_bound_offset(src_reg
);
4846 __reg_bound_offset(dst_reg
);
4847 /* Intersecting with the old var_off might have improved our bounds
4848 * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
4849 * then new var_off is (0; 0x7f...fc) which improves our umax.
4851 __update_reg_bounds(src_reg
);
4852 __update_reg_bounds(dst_reg
);
4855 static void reg_combine_min_max(struct bpf_reg_state
*true_src
,
4856 struct bpf_reg_state
*true_dst
,
4857 struct bpf_reg_state
*false_src
,
4858 struct bpf_reg_state
*false_dst
,
4863 __reg_combine_min_max(true_src
, true_dst
);
4866 __reg_combine_min_max(false_src
, false_dst
);
4871 static void mark_ptr_or_null_reg(struct bpf_func_state
*state
,
4872 struct bpf_reg_state
*reg
, u32 id
,
4875 if (reg_type_may_be_null(reg
->type
) && reg
->id
== id
) {
4876 /* Old offset (both fixed and variable parts) should
4877 * have been known-zero, because we don't allow pointer
4878 * arithmetic on pointers that might be NULL.
4880 if (WARN_ON_ONCE(reg
->smin_value
|| reg
->smax_value
||
4881 !tnum_equals_const(reg
->var_off
, 0) ||
4883 __mark_reg_known_zero(reg
);
4887 reg
->type
= SCALAR_VALUE
;
4888 } else if (reg
->type
== PTR_TO_MAP_VALUE_OR_NULL
) {
4889 if (reg
->map_ptr
->inner_map_meta
) {
4890 reg
->type
= CONST_PTR_TO_MAP
;
4891 reg
->map_ptr
= reg
->map_ptr
->inner_map_meta
;
4893 reg
->type
= PTR_TO_MAP_VALUE
;
4895 } else if (reg
->type
== PTR_TO_SOCKET_OR_NULL
) {
4896 reg
->type
= PTR_TO_SOCKET
;
4897 } else if (reg
->type
== PTR_TO_SOCK_COMMON_OR_NULL
) {
4898 reg
->type
= PTR_TO_SOCK_COMMON
;
4899 } else if (reg
->type
== PTR_TO_TCP_SOCK_OR_NULL
) {
4900 reg
->type
= PTR_TO_TCP_SOCK
;
4903 /* We don't need id and ref_obj_id from this point
4904 * onwards anymore, thus we should better reset it,
4905 * so that state pruning has chances to take effect.
4908 reg
->ref_obj_id
= 0;
4909 } else if (!reg_may_point_to_spin_lock(reg
)) {
4910 /* For not-NULL ptr, reg->ref_obj_id will be reset
4911 * in release_reg_references().
4913 * reg->id is still used by spin_lock ptr. Other
4914 * than spin_lock ptr type, reg->id can be reset.
4921 static void __mark_ptr_or_null_regs(struct bpf_func_state
*state
, u32 id
,
4924 struct bpf_reg_state
*reg
;
4927 for (i
= 0; i
< MAX_BPF_REG
; i
++)
4928 mark_ptr_or_null_reg(state
, &state
->regs
[i
], id
, is_null
);
4930 bpf_for_each_spilled_reg(i
, state
, reg
) {
4933 mark_ptr_or_null_reg(state
, reg
, id
, is_null
);
4937 /* The logic is similar to find_good_pkt_pointers(), both could eventually
4938 * be folded together at some point.
4940 static void mark_ptr_or_null_regs(struct bpf_verifier_state
*vstate
, u32 regno
,
4943 struct bpf_func_state
*state
= vstate
->frame
[vstate
->curframe
];
4944 struct bpf_reg_state
*regs
= state
->regs
;
4945 u32 ref_obj_id
= regs
[regno
].ref_obj_id
;
4946 u32 id
= regs
[regno
].id
;
4949 if (ref_obj_id
&& ref_obj_id
== id
&& is_null
)
4950 /* regs[regno] is in the " == NULL" branch.
4951 * No one could have freed the reference state before
4952 * doing the NULL check.
4954 WARN_ON_ONCE(release_reference_state(state
, id
));
4956 for (i
= 0; i
<= vstate
->curframe
; i
++)
4957 __mark_ptr_or_null_regs(vstate
->frame
[i
], id
, is_null
);
4960 static bool try_match_pkt_pointers(const struct bpf_insn
*insn
,
4961 struct bpf_reg_state
*dst_reg
,
4962 struct bpf_reg_state
*src_reg
,
4963 struct bpf_verifier_state
*this_branch
,
4964 struct bpf_verifier_state
*other_branch
)
4966 if (BPF_SRC(insn
->code
) != BPF_X
)
4969 /* Pointers are always 64-bit. */
4970 if (BPF_CLASS(insn
->code
) == BPF_JMP32
)
4973 switch (BPF_OP(insn
->code
)) {
4975 if ((dst_reg
->type
== PTR_TO_PACKET
&&
4976 src_reg
->type
== PTR_TO_PACKET_END
) ||
4977 (dst_reg
->type
== PTR_TO_PACKET_META
&&
4978 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
4979 /* pkt_data' > pkt_end, pkt_meta' > pkt_data */
4980 find_good_pkt_pointers(this_branch
, dst_reg
,
4981 dst_reg
->type
, false);
4982 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
4983 src_reg
->type
== PTR_TO_PACKET
) ||
4984 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
4985 src_reg
->type
== PTR_TO_PACKET_META
)) {
4986 /* pkt_end > pkt_data', pkt_data > pkt_meta' */
4987 find_good_pkt_pointers(other_branch
, src_reg
,
4988 src_reg
->type
, true);
4994 if ((dst_reg
->type
== PTR_TO_PACKET
&&
4995 src_reg
->type
== PTR_TO_PACKET_END
) ||
4996 (dst_reg
->type
== PTR_TO_PACKET_META
&&
4997 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
4998 /* pkt_data' < pkt_end, pkt_meta' < pkt_data */
4999 find_good_pkt_pointers(other_branch
, dst_reg
,
5000 dst_reg
->type
, true);
5001 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
5002 src_reg
->type
== PTR_TO_PACKET
) ||
5003 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
5004 src_reg
->type
== PTR_TO_PACKET_META
)) {
5005 /* pkt_end < pkt_data', pkt_data > pkt_meta' */
5006 find_good_pkt_pointers(this_branch
, src_reg
,
5007 src_reg
->type
, false);
5013 if ((dst_reg
->type
== PTR_TO_PACKET
&&
5014 src_reg
->type
== PTR_TO_PACKET_END
) ||
5015 (dst_reg
->type
== PTR_TO_PACKET_META
&&
5016 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
5017 /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
5018 find_good_pkt_pointers(this_branch
, dst_reg
,
5019 dst_reg
->type
, true);
5020 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
5021 src_reg
->type
== PTR_TO_PACKET
) ||
5022 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
5023 src_reg
->type
== PTR_TO_PACKET_META
)) {
5024 /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
5025 find_good_pkt_pointers(other_branch
, src_reg
,
5026 src_reg
->type
, false);
5032 if ((dst_reg
->type
== PTR_TO_PACKET
&&
5033 src_reg
->type
== PTR_TO_PACKET_END
) ||
5034 (dst_reg
->type
== PTR_TO_PACKET_META
&&
5035 reg_is_init_pkt_pointer(src_reg
, PTR_TO_PACKET
))) {
5036 /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
5037 find_good_pkt_pointers(other_branch
, dst_reg
,
5038 dst_reg
->type
, false);
5039 } else if ((dst_reg
->type
== PTR_TO_PACKET_END
&&
5040 src_reg
->type
== PTR_TO_PACKET
) ||
5041 (reg_is_init_pkt_pointer(dst_reg
, PTR_TO_PACKET
) &&
5042 src_reg
->type
== PTR_TO_PACKET_META
)) {
5043 /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
5044 find_good_pkt_pointers(this_branch
, src_reg
,
5045 src_reg
->type
, true);
5057 static int check_cond_jmp_op(struct bpf_verifier_env
*env
,
5058 struct bpf_insn
*insn
, int *insn_idx
)
5060 struct bpf_verifier_state
*this_branch
= env
->cur_state
;
5061 struct bpf_verifier_state
*other_branch
;
5062 struct bpf_reg_state
*regs
= this_branch
->frame
[this_branch
->curframe
]->regs
;
5063 struct bpf_reg_state
*dst_reg
, *other_branch_regs
;
5064 u8 opcode
= BPF_OP(insn
->code
);
5068 /* Only conditional jumps are expected to reach here. */
5069 if (opcode
== BPF_JA
|| opcode
> BPF_JSLE
) {
5070 verbose(env
, "invalid BPF_JMP/JMP32 opcode %x\n", opcode
);
5074 if (BPF_SRC(insn
->code
) == BPF_X
) {
5075 if (insn
->imm
!= 0) {
5076 verbose(env
, "BPF_JMP/JMP32 uses reserved fields\n");
5080 /* check src1 operand */
5081 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
5085 if (is_pointer_value(env
, insn
->src_reg
)) {
5086 verbose(env
, "R%d pointer comparison prohibited\n",
5091 if (insn
->src_reg
!= BPF_REG_0
) {
5092 verbose(env
, "BPF_JMP/JMP32 uses reserved fields\n");
5097 /* check src2 operand */
5098 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
5102 dst_reg
= ®s
[insn
->dst_reg
];
5103 is_jmp32
= BPF_CLASS(insn
->code
) == BPF_JMP32
;
5105 if (BPF_SRC(insn
->code
) == BPF_K
) {
5106 int pred
= is_branch_taken(dst_reg
, insn
->imm
, opcode
,
5110 /* only follow the goto, ignore fall-through */
5111 *insn_idx
+= insn
->off
;
5113 } else if (pred
== 0) {
5114 /* only follow fall-through branch, since
5115 * that's where the program will go
5121 other_branch
= push_stack(env
, *insn_idx
+ insn
->off
+ 1, *insn_idx
,
5125 other_branch_regs
= other_branch
->frame
[other_branch
->curframe
]->regs
;
5127 /* detect if we are comparing against a constant value so we can adjust
5128 * our min/max values for our dst register.
5129 * this is only legit if both are scalars (or pointers to the same
5130 * object, I suppose, but we don't support that right now), because
5131 * otherwise the different base pointers mean the offsets aren't
5134 if (BPF_SRC(insn
->code
) == BPF_X
) {
5135 struct bpf_reg_state
*src_reg
= ®s
[insn
->src_reg
];
5136 struct bpf_reg_state lo_reg0
= *dst_reg
;
5137 struct bpf_reg_state lo_reg1
= *src_reg
;
5138 struct bpf_reg_state
*src_lo
, *dst_lo
;
5142 coerce_reg_to_size(dst_lo
, 4);
5143 coerce_reg_to_size(src_lo
, 4);
5145 if (dst_reg
->type
== SCALAR_VALUE
&&
5146 src_reg
->type
== SCALAR_VALUE
) {
5147 if (tnum_is_const(src_reg
->var_off
) ||
5148 (is_jmp32
&& tnum_is_const(src_lo
->var_off
)))
5149 reg_set_min_max(&other_branch_regs
[insn
->dst_reg
],
5152 ? src_lo
->var_off
.value
5153 : src_reg
->var_off
.value
,
5155 else if (tnum_is_const(dst_reg
->var_off
) ||
5156 (is_jmp32
&& tnum_is_const(dst_lo
->var_off
)))
5157 reg_set_min_max_inv(&other_branch_regs
[insn
->src_reg
],
5160 ? dst_lo
->var_off
.value
5161 : dst_reg
->var_off
.value
,
5163 else if (!is_jmp32
&&
5164 (opcode
== BPF_JEQ
|| opcode
== BPF_JNE
))
5165 /* Comparing for equality, we can combine knowledge */
5166 reg_combine_min_max(&other_branch_regs
[insn
->src_reg
],
5167 &other_branch_regs
[insn
->dst_reg
],
5168 src_reg
, dst_reg
, opcode
);
5170 } else if (dst_reg
->type
== SCALAR_VALUE
) {
5171 reg_set_min_max(&other_branch_regs
[insn
->dst_reg
],
5172 dst_reg
, insn
->imm
, opcode
, is_jmp32
);
5175 /* detect if R == 0 where R is returned from bpf_map_lookup_elem().
5176 * NOTE: these optimizations below are related with pointer comparison
5177 * which will never be JMP32.
5179 if (!is_jmp32
&& BPF_SRC(insn
->code
) == BPF_K
&&
5180 insn
->imm
== 0 && (opcode
== BPF_JEQ
|| opcode
== BPF_JNE
) &&
5181 reg_type_may_be_null(dst_reg
->type
)) {
5182 /* Mark all identical registers in each branch as either
5183 * safe or unknown depending R == 0 or R != 0 conditional.
5185 mark_ptr_or_null_regs(this_branch
, insn
->dst_reg
,
5187 mark_ptr_or_null_regs(other_branch
, insn
->dst_reg
,
5189 } else if (!try_match_pkt_pointers(insn
, dst_reg
, ®s
[insn
->src_reg
],
5190 this_branch
, other_branch
) &&
5191 is_pointer_value(env
, insn
->dst_reg
)) {
5192 verbose(env
, "R%d pointer comparison prohibited\n",
5196 if (env
->log
.level
& BPF_LOG_LEVEL
)
5197 print_verifier_state(env
, this_branch
->frame
[this_branch
->curframe
]);
5201 /* verify BPF_LD_IMM64 instruction */
5202 static int check_ld_imm(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
5204 struct bpf_insn_aux_data
*aux
= cur_aux(env
);
5205 struct bpf_reg_state
*regs
= cur_regs(env
);
5206 struct bpf_map
*map
;
5209 if (BPF_SIZE(insn
->code
) != BPF_DW
) {
5210 verbose(env
, "invalid BPF_LD_IMM insn\n");
5213 if (insn
->off
!= 0) {
5214 verbose(env
, "BPF_LD_IMM64 uses reserved fields\n");
5218 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP
);
5222 if (insn
->src_reg
== 0) {
5223 u64 imm
= ((u64
)(insn
+ 1)->imm
<< 32) | (u32
)insn
->imm
;
5225 regs
[insn
->dst_reg
].type
= SCALAR_VALUE
;
5226 __mark_reg_known(®s
[insn
->dst_reg
], imm
);
5230 map
= env
->used_maps
[aux
->map_index
];
5231 mark_reg_known_zero(env
, regs
, insn
->dst_reg
);
5232 regs
[insn
->dst_reg
].map_ptr
= map
;
5234 if (insn
->src_reg
== BPF_PSEUDO_MAP_VALUE
) {
5235 regs
[insn
->dst_reg
].type
= PTR_TO_MAP_VALUE
;
5236 regs
[insn
->dst_reg
].off
= aux
->map_off
;
5237 if (map_value_has_spin_lock(map
))
5238 regs
[insn
->dst_reg
].id
= ++env
->id_gen
;
5239 } else if (insn
->src_reg
== BPF_PSEUDO_MAP_FD
) {
5240 regs
[insn
->dst_reg
].type
= CONST_PTR_TO_MAP
;
5242 verbose(env
, "bpf verifier is misconfigured\n");
5249 static bool may_access_skb(enum bpf_prog_type type
)
5252 case BPF_PROG_TYPE_SOCKET_FILTER
:
5253 case BPF_PROG_TYPE_SCHED_CLS
:
5254 case BPF_PROG_TYPE_SCHED_ACT
:
5261 /* verify safety of LD_ABS|LD_IND instructions:
5262 * - they can only appear in the programs where ctx == skb
5263 * - since they are wrappers of function calls, they scratch R1-R5 registers,
5264 * preserve R6-R9, and store return value into R0
5267 * ctx == skb == R6 == CTX
5270 * SRC == any register
5271 * IMM == 32-bit immediate
5274 * R0 - 8/16/32-bit skb data converted to cpu endianness
5276 static int check_ld_abs(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
5278 struct bpf_reg_state
*regs
= cur_regs(env
);
5279 u8 mode
= BPF_MODE(insn
->code
);
5282 if (!may_access_skb(env
->prog
->type
)) {
5283 verbose(env
, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
5287 if (!env
->ops
->gen_ld_abs
) {
5288 verbose(env
, "bpf verifier is misconfigured\n");
5292 if (env
->subprog_cnt
> 1) {
5293 /* when program has LD_ABS insn JITs and interpreter assume
5294 * that r1 == ctx == skb which is not the case for callees
5295 * that can have arbitrary arguments. It's problematic
5296 * for main prog as well since JITs would need to analyze
5297 * all functions in order to make proper register save/restore
5298 * decisions in the main prog. Hence disallow LD_ABS with calls
5300 verbose(env
, "BPF_LD_[ABS|IND] instructions cannot be mixed with bpf-to-bpf calls\n");
5304 if (insn
->dst_reg
!= BPF_REG_0
|| insn
->off
!= 0 ||
5305 BPF_SIZE(insn
->code
) == BPF_DW
||
5306 (mode
== BPF_ABS
&& insn
->src_reg
!= BPF_REG_0
)) {
5307 verbose(env
, "BPF_LD_[ABS|IND] uses reserved fields\n");
5311 /* check whether implicit source operand (register R6) is readable */
5312 err
= check_reg_arg(env
, BPF_REG_6
, SRC_OP
);
5316 /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
5317 * gen_ld_abs() may terminate the program at runtime, leading to
5320 err
= check_reference_leak(env
);
5322 verbose(env
, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
5326 if (env
->cur_state
->active_spin_lock
) {
5327 verbose(env
, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
5331 if (regs
[BPF_REG_6
].type
!= PTR_TO_CTX
) {
5333 "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
5337 if (mode
== BPF_IND
) {
5338 /* check explicit source operand */
5339 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
5344 /* reset caller saved regs to unreadable */
5345 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
5346 mark_reg_not_init(env
, regs
, caller_saved
[i
]);
5347 check_reg_arg(env
, caller_saved
[i
], DST_OP_NO_MARK
);
5350 /* mark destination R0 register as readable, since it contains
5351 * the value fetched from the packet.
5352 * Already marked as written above.
5354 mark_reg_unknown(env
, regs
, BPF_REG_0
);
5358 static int check_return_code(struct bpf_verifier_env
*env
)
5360 struct bpf_reg_state
*reg
;
5361 struct tnum range
= tnum_range(0, 1);
5363 switch (env
->prog
->type
) {
5364 case BPF_PROG_TYPE_CGROUP_SKB
:
5365 case BPF_PROG_TYPE_CGROUP_SOCK
:
5366 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR
:
5367 case BPF_PROG_TYPE_SOCK_OPS
:
5368 case BPF_PROG_TYPE_CGROUP_DEVICE
:
5369 case BPF_PROG_TYPE_CGROUP_SYSCTL
:
5375 reg
= cur_regs(env
) + BPF_REG_0
;
5376 if (reg
->type
!= SCALAR_VALUE
) {
5377 verbose(env
, "At program exit the register R0 is not a known value (%s)\n",
5378 reg_type_str
[reg
->type
]);
5382 if (!tnum_in(range
, reg
->var_off
)) {
5383 verbose(env
, "At program exit the register R0 ");
5384 if (!tnum_is_unknown(reg
->var_off
)) {
5387 tnum_strn(tn_buf
, sizeof(tn_buf
), reg
->var_off
);
5388 verbose(env
, "has value %s", tn_buf
);
5390 verbose(env
, "has unknown scalar value");
5392 verbose(env
, " should have been 0 or 1\n");
5398 /* non-recursive DFS pseudo code
5399 * 1 procedure DFS-iterative(G,v):
5400 * 2 label v as discovered
5401 * 3 let S be a stack
5403 * 5 while S is not empty
5405 * 7 if t is what we're looking for:
5407 * 9 for all edges e in G.adjacentEdges(t) do
5408 * 10 if edge e is already labelled
5409 * 11 continue with the next edge
5410 * 12 w <- G.adjacentVertex(t,e)
5411 * 13 if vertex w is not discovered and not explored
5412 * 14 label e as tree-edge
5413 * 15 label w as discovered
5416 * 18 else if vertex w is discovered
5417 * 19 label e as back-edge
5419 * 21 // vertex w is explored
5420 * 22 label e as forward- or cross-edge
5421 * 23 label t as explored
5426 * 0x11 - discovered and fall-through edge labelled
5427 * 0x12 - discovered and fall-through and branch edges labelled
5438 #define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L)
5440 /* t, w, e - match pseudo-code above:
5441 * t - index of current instruction
5442 * w - next instruction
5445 static int push_insn(int t
, int w
, int e
, struct bpf_verifier_env
*env
)
5447 int *insn_stack
= env
->cfg
.insn_stack
;
5448 int *insn_state
= env
->cfg
.insn_state
;
5450 if (e
== FALLTHROUGH
&& insn_state
[t
] >= (DISCOVERED
| FALLTHROUGH
))
5453 if (e
== BRANCH
&& insn_state
[t
] >= (DISCOVERED
| BRANCH
))
5456 if (w
< 0 || w
>= env
->prog
->len
) {
5457 verbose_linfo(env
, t
, "%d: ", t
);
5458 verbose(env
, "jump out of range from insn %d to %d\n", t
, w
);
5463 /* mark branch target for state pruning */
5464 env
->explored_states
[w
] = STATE_LIST_MARK
;
5466 if (insn_state
[w
] == 0) {
5468 insn_state
[t
] = DISCOVERED
| e
;
5469 insn_state
[w
] = DISCOVERED
;
5470 if (env
->cfg
.cur_stack
>= env
->prog
->len
)
5472 insn_stack
[env
->cfg
.cur_stack
++] = w
;
5474 } else if ((insn_state
[w
] & 0xF0) == DISCOVERED
) {
5475 verbose_linfo(env
, t
, "%d: ", t
);
5476 verbose_linfo(env
, w
, "%d: ", w
);
5477 verbose(env
, "back-edge from insn %d to %d\n", t
, w
);
5479 } else if (insn_state
[w
] == EXPLORED
) {
5480 /* forward- or cross-edge */
5481 insn_state
[t
] = DISCOVERED
| e
;
5483 verbose(env
, "insn state internal bug\n");
5489 /* non-recursive depth-first-search to detect loops in BPF program
5490 * loop == back-edge in directed graph
5492 static int check_cfg(struct bpf_verifier_env
*env
)
5494 struct bpf_insn
*insns
= env
->prog
->insnsi
;
5495 int insn_cnt
= env
->prog
->len
;
5496 int *insn_stack
, *insn_state
;
5500 insn_state
= env
->cfg
.insn_state
= kvcalloc(insn_cnt
, sizeof(int), GFP_KERNEL
);
5504 insn_stack
= env
->cfg
.insn_stack
= kvcalloc(insn_cnt
, sizeof(int), GFP_KERNEL
);
5510 insn_state
[0] = DISCOVERED
; /* mark 1st insn as discovered */
5511 insn_stack
[0] = 0; /* 0 is the first instruction */
5512 env
->cfg
.cur_stack
= 1;
5515 if (env
->cfg
.cur_stack
== 0)
5517 t
= insn_stack
[env
->cfg
.cur_stack
- 1];
5519 if (BPF_CLASS(insns
[t
].code
) == BPF_JMP
||
5520 BPF_CLASS(insns
[t
].code
) == BPF_JMP32
) {
5521 u8 opcode
= BPF_OP(insns
[t
].code
);
5523 if (opcode
== BPF_EXIT
) {
5525 } else if (opcode
== BPF_CALL
) {
5526 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
);
5531 if (t
+ 1 < insn_cnt
)
5532 env
->explored_states
[t
+ 1] = STATE_LIST_MARK
;
5533 if (insns
[t
].src_reg
== BPF_PSEUDO_CALL
) {
5534 env
->explored_states
[t
] = STATE_LIST_MARK
;
5535 ret
= push_insn(t
, t
+ insns
[t
].imm
+ 1, BRANCH
, env
);
5541 } else if (opcode
== BPF_JA
) {
5542 if (BPF_SRC(insns
[t
].code
) != BPF_K
) {
5546 /* unconditional jump with single edge */
5547 ret
= push_insn(t
, t
+ insns
[t
].off
+ 1,
5553 /* tell verifier to check for equivalent states
5554 * after every call and jump
5556 if (t
+ 1 < insn_cnt
)
5557 env
->explored_states
[t
+ 1] = STATE_LIST_MARK
;
5559 /* conditional jump with two edges */
5560 env
->explored_states
[t
] = STATE_LIST_MARK
;
5561 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
);
5567 ret
= push_insn(t
, t
+ insns
[t
].off
+ 1, BRANCH
, env
);
5574 /* all other non-branch instructions with single
5577 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
);
5585 insn_state
[t
] = EXPLORED
;
5586 if (env
->cfg
.cur_stack
-- <= 0) {
5587 verbose(env
, "pop stack internal bug\n");
5594 for (i
= 0; i
< insn_cnt
; i
++) {
5595 if (insn_state
[i
] != EXPLORED
) {
5596 verbose(env
, "unreachable insn %d\n", i
);
5601 ret
= 0; /* cfg looks good */
5606 env
->cfg
.insn_state
= env
->cfg
.insn_stack
= NULL
;
5610 /* The minimum supported BTF func info size */
5611 #define MIN_BPF_FUNCINFO_SIZE 8
5612 #define MAX_FUNCINFO_REC_SIZE 252
5614 static int check_btf_func(struct bpf_verifier_env
*env
,
5615 const union bpf_attr
*attr
,
5616 union bpf_attr __user
*uattr
)
5618 u32 i
, nfuncs
, urec_size
, min_size
;
5619 u32 krec_size
= sizeof(struct bpf_func_info
);
5620 struct bpf_func_info
*krecord
;
5621 const struct btf_type
*type
;
5622 struct bpf_prog
*prog
;
5623 const struct btf
*btf
;
5624 void __user
*urecord
;
5625 u32 prev_offset
= 0;
5628 nfuncs
= attr
->func_info_cnt
;
5632 if (nfuncs
!= env
->subprog_cnt
) {
5633 verbose(env
, "number of funcs in func_info doesn't match number of subprogs\n");
5637 urec_size
= attr
->func_info_rec_size
;
5638 if (urec_size
< MIN_BPF_FUNCINFO_SIZE
||
5639 urec_size
> MAX_FUNCINFO_REC_SIZE
||
5640 urec_size
% sizeof(u32
)) {
5641 verbose(env
, "invalid func info rec size %u\n", urec_size
);
5646 btf
= prog
->aux
->btf
;
5648 urecord
= u64_to_user_ptr(attr
->func_info
);
5649 min_size
= min_t(u32
, krec_size
, urec_size
);
5651 krecord
= kvcalloc(nfuncs
, krec_size
, GFP_KERNEL
| __GFP_NOWARN
);
5655 for (i
= 0; i
< nfuncs
; i
++) {
5656 ret
= bpf_check_uarg_tail_zero(urecord
, krec_size
, urec_size
);
5658 if (ret
== -E2BIG
) {
5659 verbose(env
, "nonzero tailing record in func info");
5660 /* set the size kernel expects so loader can zero
5661 * out the rest of the record.
5663 if (put_user(min_size
, &uattr
->func_info_rec_size
))
5669 if (copy_from_user(&krecord
[i
], urecord
, min_size
)) {
5674 /* check insn_off */
5676 if (krecord
[i
].insn_off
) {
5678 "nonzero insn_off %u for the first func info record",
5679 krecord
[i
].insn_off
);
5683 } else if (krecord
[i
].insn_off
<= prev_offset
) {
5685 "same or smaller insn offset (%u) than previous func info record (%u)",
5686 krecord
[i
].insn_off
, prev_offset
);
5691 if (env
->subprog_info
[i
].start
!= krecord
[i
].insn_off
) {
5692 verbose(env
, "func_info BTF section doesn't match subprog layout in BPF program\n");
5698 type
= btf_type_by_id(btf
, krecord
[i
].type_id
);
5699 if (!type
|| BTF_INFO_KIND(type
->info
) != BTF_KIND_FUNC
) {
5700 verbose(env
, "invalid type id %d in func info",
5701 krecord
[i
].type_id
);
5706 prev_offset
= krecord
[i
].insn_off
;
5707 urecord
+= urec_size
;
5710 prog
->aux
->func_info
= krecord
;
5711 prog
->aux
->func_info_cnt
= nfuncs
;
5719 static void adjust_btf_func(struct bpf_verifier_env
*env
)
5723 if (!env
->prog
->aux
->func_info
)
5726 for (i
= 0; i
< env
->subprog_cnt
; i
++)
5727 env
->prog
->aux
->func_info
[i
].insn_off
= env
->subprog_info
[i
].start
;
5730 #define MIN_BPF_LINEINFO_SIZE (offsetof(struct bpf_line_info, line_col) + \
5731 sizeof(((struct bpf_line_info *)(0))->line_col))
5732 #define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE
5734 static int check_btf_line(struct bpf_verifier_env
*env
,
5735 const union bpf_attr
*attr
,
5736 union bpf_attr __user
*uattr
)
5738 u32 i
, s
, nr_linfo
, ncopy
, expected_size
, rec_size
, prev_offset
= 0;
5739 struct bpf_subprog_info
*sub
;
5740 struct bpf_line_info
*linfo
;
5741 struct bpf_prog
*prog
;
5742 const struct btf
*btf
;
5743 void __user
*ulinfo
;
5746 nr_linfo
= attr
->line_info_cnt
;
5750 rec_size
= attr
->line_info_rec_size
;
5751 if (rec_size
< MIN_BPF_LINEINFO_SIZE
||
5752 rec_size
> MAX_LINEINFO_REC_SIZE
||
5753 rec_size
& (sizeof(u32
) - 1))
5756 /* Need to zero it in case the userspace may
5757 * pass in a smaller bpf_line_info object.
5759 linfo
= kvcalloc(nr_linfo
, sizeof(struct bpf_line_info
),
5760 GFP_KERNEL
| __GFP_NOWARN
);
5765 btf
= prog
->aux
->btf
;
5768 sub
= env
->subprog_info
;
5769 ulinfo
= u64_to_user_ptr(attr
->line_info
);
5770 expected_size
= sizeof(struct bpf_line_info
);
5771 ncopy
= min_t(u32
, expected_size
, rec_size
);
5772 for (i
= 0; i
< nr_linfo
; i
++) {
5773 err
= bpf_check_uarg_tail_zero(ulinfo
, expected_size
, rec_size
);
5775 if (err
== -E2BIG
) {
5776 verbose(env
, "nonzero tailing record in line_info");
5777 if (put_user(expected_size
,
5778 &uattr
->line_info_rec_size
))
5784 if (copy_from_user(&linfo
[i
], ulinfo
, ncopy
)) {
5790 * Check insn_off to ensure
5791 * 1) strictly increasing AND
5792 * 2) bounded by prog->len
5794 * The linfo[0].insn_off == 0 check logically falls into
5795 * the later "missing bpf_line_info for func..." case
5796 * because the first linfo[0].insn_off must be the
5797 * first sub also and the first sub must have
5798 * subprog_info[0].start == 0.
5800 if ((i
&& linfo
[i
].insn_off
<= prev_offset
) ||
5801 linfo
[i
].insn_off
>= prog
->len
) {
5802 verbose(env
, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
5803 i
, linfo
[i
].insn_off
, prev_offset
,
5809 if (!prog
->insnsi
[linfo
[i
].insn_off
].code
) {
5811 "Invalid insn code at line_info[%u].insn_off\n",
5817 if (!btf_name_by_offset(btf
, linfo
[i
].line_off
) ||
5818 !btf_name_by_offset(btf
, linfo
[i
].file_name_off
)) {
5819 verbose(env
, "Invalid line_info[%u].line_off or .file_name_off\n", i
);
5824 if (s
!= env
->subprog_cnt
) {
5825 if (linfo
[i
].insn_off
== sub
[s
].start
) {
5826 sub
[s
].linfo_idx
= i
;
5828 } else if (sub
[s
].start
< linfo
[i
].insn_off
) {
5829 verbose(env
, "missing bpf_line_info for func#%u\n", s
);
5835 prev_offset
= linfo
[i
].insn_off
;
5839 if (s
!= env
->subprog_cnt
) {
5840 verbose(env
, "missing bpf_line_info for %u funcs starting from func#%u\n",
5841 env
->subprog_cnt
- s
, s
);
5846 prog
->aux
->linfo
= linfo
;
5847 prog
->aux
->nr_linfo
= nr_linfo
;
5856 static int check_btf_info(struct bpf_verifier_env
*env
,
5857 const union bpf_attr
*attr
,
5858 union bpf_attr __user
*uattr
)
5863 if (!attr
->func_info_cnt
&& !attr
->line_info_cnt
)
5866 btf
= btf_get_by_fd(attr
->prog_btf_fd
);
5868 return PTR_ERR(btf
);
5869 env
->prog
->aux
->btf
= btf
;
5871 err
= check_btf_func(env
, attr
, uattr
);
5875 err
= check_btf_line(env
, attr
, uattr
);
5882 /* check %cur's range satisfies %old's */
5883 static bool range_within(struct bpf_reg_state
*old
,
5884 struct bpf_reg_state
*cur
)
5886 return old
->umin_value
<= cur
->umin_value
&&
5887 old
->umax_value
>= cur
->umax_value
&&
5888 old
->smin_value
<= cur
->smin_value
&&
5889 old
->smax_value
>= cur
->smax_value
;
5892 /* Maximum number of register states that can exist at once */
5893 #define ID_MAP_SIZE (MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE)
5899 /* If in the old state two registers had the same id, then they need to have
5900 * the same id in the new state as well. But that id could be different from
5901 * the old state, so we need to track the mapping from old to new ids.
5902 * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent
5903 * regs with old id 5 must also have new id 9 for the new state to be safe. But
5904 * regs with a different old id could still have new id 9, we don't care about
5906 * So we look through our idmap to see if this old id has been seen before. If
5907 * so, we require the new id to match; otherwise, we add the id pair to the map.
5909 static bool check_ids(u32 old_id
, u32 cur_id
, struct idpair
*idmap
)
5913 for (i
= 0; i
< ID_MAP_SIZE
; i
++) {
5914 if (!idmap
[i
].old
) {
5915 /* Reached an empty slot; haven't seen this id before */
5916 idmap
[i
].old
= old_id
;
5917 idmap
[i
].cur
= cur_id
;
5920 if (idmap
[i
].old
== old_id
)
5921 return idmap
[i
].cur
== cur_id
;
5923 /* We ran out of idmap slots, which should be impossible */
5928 static void clean_func_state(struct bpf_verifier_env
*env
,
5929 struct bpf_func_state
*st
)
5931 enum bpf_reg_liveness live
;
5934 for (i
= 0; i
< BPF_REG_FP
; i
++) {
5935 live
= st
->regs
[i
].live
;
5936 /* liveness must not touch this register anymore */
5937 st
->regs
[i
].live
|= REG_LIVE_DONE
;
5938 if (!(live
& REG_LIVE_READ
))
5939 /* since the register is unused, clear its state
5940 * to make further comparison simpler
5942 __mark_reg_not_init(&st
->regs
[i
]);
5945 for (i
= 0; i
< st
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
5946 live
= st
->stack
[i
].spilled_ptr
.live
;
5947 /* liveness must not touch this stack slot anymore */
5948 st
->stack
[i
].spilled_ptr
.live
|= REG_LIVE_DONE
;
5949 if (!(live
& REG_LIVE_READ
)) {
5950 __mark_reg_not_init(&st
->stack
[i
].spilled_ptr
);
5951 for (j
= 0; j
< BPF_REG_SIZE
; j
++)
5952 st
->stack
[i
].slot_type
[j
] = STACK_INVALID
;
5957 static void clean_verifier_state(struct bpf_verifier_env
*env
,
5958 struct bpf_verifier_state
*st
)
5962 if (st
->frame
[0]->regs
[0].live
& REG_LIVE_DONE
)
5963 /* all regs in this state in all frames were already marked */
5966 for (i
= 0; i
<= st
->curframe
; i
++)
5967 clean_func_state(env
, st
->frame
[i
]);
5970 /* the parentage chains form a tree.
5971 * the verifier states are added to state lists at given insn and
5972 * pushed into state stack for future exploration.
5973 * when the verifier reaches bpf_exit insn some of the verifer states
5974 * stored in the state lists have their final liveness state already,
5975 * but a lot of states will get revised from liveness point of view when
5976 * the verifier explores other branches.
5979 * 2: if r1 == 100 goto pc+1
5982 * when the verifier reaches exit insn the register r0 in the state list of
5983 * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
5984 * of insn 2 and goes exploring further. At the insn 4 it will walk the
5985 * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
5987 * Since the verifier pushes the branch states as it sees them while exploring
5988 * the program the condition of walking the branch instruction for the second
5989 * time means that all states below this branch were already explored and
5990 * their final liveness markes are already propagated.
5991 * Hence when the verifier completes the search of state list in is_state_visited()
5992 * we can call this clean_live_states() function to mark all liveness states
5993 * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
5995 * This function also clears the registers and stack for states that !READ
5996 * to simplify state merging.
5998 * Important note here that walking the same branch instruction in the callee
5999 * doesn't meant that the states are DONE. The verifier has to compare
6002 static void clean_live_states(struct bpf_verifier_env
*env
, int insn
,
6003 struct bpf_verifier_state
*cur
)
6005 struct bpf_verifier_state_list
*sl
;
6008 sl
= env
->explored_states
[insn
];
6012 while (sl
!= STATE_LIST_MARK
) {
6013 if (sl
->state
.curframe
!= cur
->curframe
)
6015 for (i
= 0; i
<= cur
->curframe
; i
++)
6016 if (sl
->state
.frame
[i
]->callsite
!= cur
->frame
[i
]->callsite
)
6018 clean_verifier_state(env
, &sl
->state
);
6024 /* Returns true if (rold safe implies rcur safe) */
6025 static bool regsafe(struct bpf_reg_state
*rold
, struct bpf_reg_state
*rcur
,
6026 struct idpair
*idmap
)
6030 if (!(rold
->live
& REG_LIVE_READ
))
6031 /* explored state didn't use this */
6034 equal
= memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, parent
)) == 0;
6036 if (rold
->type
== PTR_TO_STACK
)
6037 /* two stack pointers are equal only if they're pointing to
6038 * the same stack frame, since fp-8 in foo != fp-8 in bar
6040 return equal
&& rold
->frameno
== rcur
->frameno
;
6045 if (rold
->type
== NOT_INIT
)
6046 /* explored state can't have used this */
6048 if (rcur
->type
== NOT_INIT
)
6050 switch (rold
->type
) {
6052 if (rcur
->type
== SCALAR_VALUE
) {
6053 /* new val must satisfy old val knowledge */
6054 return range_within(rold
, rcur
) &&
6055 tnum_in(rold
->var_off
, rcur
->var_off
);
6057 /* We're trying to use a pointer in place of a scalar.
6058 * Even if the scalar was unbounded, this could lead to
6059 * pointer leaks because scalars are allowed to leak
6060 * while pointers are not. We could make this safe in
6061 * special cases if root is calling us, but it's
6062 * probably not worth the hassle.
6066 case PTR_TO_MAP_VALUE
:
6067 /* If the new min/max/var_off satisfy the old ones and
6068 * everything else matches, we are OK.
6069 * 'id' is not compared, since it's only used for maps with
6070 * bpf_spin_lock inside map element and in such cases if
6071 * the rest of the prog is valid for one map element then
6072 * it's valid for all map elements regardless of the key
6073 * used in bpf_map_lookup()
6075 return memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, id
)) == 0 &&
6076 range_within(rold
, rcur
) &&
6077 tnum_in(rold
->var_off
, rcur
->var_off
);
6078 case PTR_TO_MAP_VALUE_OR_NULL
:
6079 /* a PTR_TO_MAP_VALUE could be safe to use as a
6080 * PTR_TO_MAP_VALUE_OR_NULL into the same map.
6081 * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL-
6082 * checked, doing so could have affected others with the same
6083 * id, and we can't check for that because we lost the id when
6084 * we converted to a PTR_TO_MAP_VALUE.
6086 if (rcur
->type
!= PTR_TO_MAP_VALUE_OR_NULL
)
6088 if (memcmp(rold
, rcur
, offsetof(struct bpf_reg_state
, id
)))
6090 /* Check our ids match any regs they're supposed to */
6091 return check_ids(rold
->id
, rcur
->id
, idmap
);
6092 case PTR_TO_PACKET_META
:
6094 if (rcur
->type
!= rold
->type
)
6096 /* We must have at least as much range as the old ptr
6097 * did, so that any accesses which were safe before are
6098 * still safe. This is true even if old range < old off,
6099 * since someone could have accessed through (ptr - k), or
6100 * even done ptr -= k in a register, to get a safe access.
6102 if (rold
->range
> rcur
->range
)
6104 /* If the offsets don't match, we can't trust our alignment;
6105 * nor can we be sure that we won't fall out of range.
6107 if (rold
->off
!= rcur
->off
)
6109 /* id relations must be preserved */
6110 if (rold
->id
&& !check_ids(rold
->id
, rcur
->id
, idmap
))
6112 /* new val must satisfy old val knowledge */
6113 return range_within(rold
, rcur
) &&
6114 tnum_in(rold
->var_off
, rcur
->var_off
);
6116 case CONST_PTR_TO_MAP
:
6117 case PTR_TO_PACKET_END
:
6118 case PTR_TO_FLOW_KEYS
:
6120 case PTR_TO_SOCKET_OR_NULL
:
6121 case PTR_TO_SOCK_COMMON
:
6122 case PTR_TO_SOCK_COMMON_OR_NULL
:
6123 case PTR_TO_TCP_SOCK
:
6124 case PTR_TO_TCP_SOCK_OR_NULL
:
6125 /* Only valid matches are exact, which memcmp() above
6126 * would have accepted
6129 /* Don't know what's going on, just say it's not safe */
6133 /* Shouldn't get here; if we do, say it's not safe */
6138 static bool stacksafe(struct bpf_func_state
*old
,
6139 struct bpf_func_state
*cur
,
6140 struct idpair
*idmap
)
6144 /* walk slots of the explored stack and ignore any additional
6145 * slots in the current stack, since explored(safe) state
6148 for (i
= 0; i
< old
->allocated_stack
; i
++) {
6149 spi
= i
/ BPF_REG_SIZE
;
6151 if (!(old
->stack
[spi
].spilled_ptr
.live
& REG_LIVE_READ
)) {
6152 i
+= BPF_REG_SIZE
- 1;
6153 /* explored state didn't use this */
6157 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_INVALID
)
6160 /* explored stack has more populated slots than current stack
6161 * and these slots were used
6163 if (i
>= cur
->allocated_stack
)
6166 /* if old state was safe with misc data in the stack
6167 * it will be safe with zero-initialized stack.
6168 * The opposite is not true
6170 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_MISC
&&
6171 cur
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] == STACK_ZERO
)
6173 if (old
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
] !=
6174 cur
->stack
[spi
].slot_type
[i
% BPF_REG_SIZE
])
6175 /* Ex: old explored (safe) state has STACK_SPILL in
6176 * this stack slot, but current has has STACK_MISC ->
6177 * this verifier states are not equivalent,
6178 * return false to continue verification of this path
6181 if (i
% BPF_REG_SIZE
)
6183 if (old
->stack
[spi
].slot_type
[0] != STACK_SPILL
)
6185 if (!regsafe(&old
->stack
[spi
].spilled_ptr
,
6186 &cur
->stack
[spi
].spilled_ptr
,
6188 /* when explored and current stack slot are both storing
6189 * spilled registers, check that stored pointers types
6190 * are the same as well.
6191 * Ex: explored safe path could have stored
6192 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
6193 * but current path has stored:
6194 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
6195 * such verifier states are not equivalent.
6196 * return false to continue verification of this path
6203 static bool refsafe(struct bpf_func_state
*old
, struct bpf_func_state
*cur
)
6205 if (old
->acquired_refs
!= cur
->acquired_refs
)
6207 return !memcmp(old
->refs
, cur
->refs
,
6208 sizeof(*old
->refs
) * old
->acquired_refs
);
6211 /* compare two verifier states
6213 * all states stored in state_list are known to be valid, since
6214 * verifier reached 'bpf_exit' instruction through them
6216 * this function is called when verifier exploring different branches of
6217 * execution popped from the state stack. If it sees an old state that has
6218 * more strict register state and more strict stack state then this execution
6219 * branch doesn't need to be explored further, since verifier already
6220 * concluded that more strict state leads to valid finish.
6222 * Therefore two states are equivalent if register state is more conservative
6223 * and explored stack state is more conservative than the current one.
6226 * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
6227 * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
6229 * In other words if current stack state (one being explored) has more
6230 * valid slots than old one that already passed validation, it means
6231 * the verifier can stop exploring and conclude that current state is valid too
6233 * Similarly with registers. If explored state has register type as invalid
6234 * whereas register type in current state is meaningful, it means that
6235 * the current state will reach 'bpf_exit' instruction safely
6237 static bool func_states_equal(struct bpf_func_state
*old
,
6238 struct bpf_func_state
*cur
)
6240 struct idpair
*idmap
;
6244 idmap
= kcalloc(ID_MAP_SIZE
, sizeof(struct idpair
), GFP_KERNEL
);
6245 /* If we failed to allocate the idmap, just say it's not safe */
6249 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
6250 if (!regsafe(&old
->regs
[i
], &cur
->regs
[i
], idmap
))
6254 if (!stacksafe(old
, cur
, idmap
))
6257 if (!refsafe(old
, cur
))
6265 static bool states_equal(struct bpf_verifier_env
*env
,
6266 struct bpf_verifier_state
*old
,
6267 struct bpf_verifier_state
*cur
)
6271 if (old
->curframe
!= cur
->curframe
)
6274 /* Verification state from speculative execution simulation
6275 * must never prune a non-speculative execution one.
6277 if (old
->speculative
&& !cur
->speculative
)
6280 if (old
->active_spin_lock
!= cur
->active_spin_lock
)
6283 /* for states to be equal callsites have to be the same
6284 * and all frame states need to be equivalent
6286 for (i
= 0; i
<= old
->curframe
; i
++) {
6287 if (old
->frame
[i
]->callsite
!= cur
->frame
[i
]->callsite
)
6289 if (!func_states_equal(old
->frame
[i
], cur
->frame
[i
]))
6295 static int propagate_liveness_reg(struct bpf_verifier_env
*env
,
6296 struct bpf_reg_state
*reg
,
6297 struct bpf_reg_state
*parent_reg
)
6301 if (parent_reg
->live
& REG_LIVE_READ
|| !(reg
->live
& REG_LIVE_READ
))
6304 err
= mark_reg_read(env
, reg
, parent_reg
);
6311 /* A write screens off any subsequent reads; but write marks come from the
6312 * straight-line code between a state and its parent. When we arrive at an
6313 * equivalent state (jump target or such) we didn't arrive by the straight-line
6314 * code, so read marks in the state must propagate to the parent regardless
6315 * of the state's write marks. That's what 'parent == state->parent' comparison
6316 * in mark_reg_read() is for.
6318 static int propagate_liveness(struct bpf_verifier_env
*env
,
6319 const struct bpf_verifier_state
*vstate
,
6320 struct bpf_verifier_state
*vparent
)
6322 struct bpf_reg_state
*state_reg
, *parent_reg
;
6323 struct bpf_func_state
*state
, *parent
;
6324 int i
, frame
, err
= 0;
6326 if (vparent
->curframe
!= vstate
->curframe
) {
6327 WARN(1, "propagate_live: parent frame %d current frame %d\n",
6328 vparent
->curframe
, vstate
->curframe
);
6331 /* Propagate read liveness of registers... */
6332 BUILD_BUG_ON(BPF_REG_FP
+ 1 != MAX_BPF_REG
);
6333 for (frame
= 0; frame
<= vstate
->curframe
; frame
++) {
6334 parent
= vparent
->frame
[frame
];
6335 state
= vstate
->frame
[frame
];
6336 parent_reg
= parent
->regs
;
6337 state_reg
= state
->regs
;
6338 /* We don't need to worry about FP liveness, it's read-only */
6339 for (i
= frame
< vstate
->curframe
? BPF_REG_6
: 0; i
< BPF_REG_FP
; i
++) {
6340 err
= propagate_liveness_reg(env
, &state_reg
[i
],
6346 /* Propagate stack slots. */
6347 for (i
= 0; i
< state
->allocated_stack
/ BPF_REG_SIZE
&&
6348 i
< parent
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
6349 parent_reg
= &parent
->stack
[i
].spilled_ptr
;
6350 state_reg
= &state
->stack
[i
].spilled_ptr
;
6351 err
= propagate_liveness_reg(env
, state_reg
,
6360 static int is_state_visited(struct bpf_verifier_env
*env
, int insn_idx
)
6362 struct bpf_verifier_state_list
*new_sl
;
6363 struct bpf_verifier_state_list
*sl
, **pprev
;
6364 struct bpf_verifier_state
*cur
= env
->cur_state
, *new;
6365 int i
, j
, err
, states_cnt
= 0;
6367 pprev
= &env
->explored_states
[insn_idx
];
6371 /* this 'insn_idx' instruction wasn't marked, so we will not
6372 * be doing state search here
6376 clean_live_states(env
, insn_idx
, cur
);
6378 while (sl
!= STATE_LIST_MARK
) {
6379 if (states_equal(env
, &sl
->state
, cur
)) {
6381 /* reached equivalent register/stack state,
6383 * Registers read by the continuation are read by us.
6384 * If we have any write marks in env->cur_state, they
6385 * will prevent corresponding reads in the continuation
6386 * from reaching our parent (an explored_state). Our
6387 * own state will get the read marks recorded, but
6388 * they'll be immediately forgotten as we're pruning
6389 * this state and will pop a new one.
6391 err
= propagate_liveness(env
, &sl
->state
, cur
);
6398 /* heuristic to determine whether this state is beneficial
6399 * to keep checking from state equivalence point of view.
6400 * Higher numbers increase max_states_per_insn and verification time,
6401 * but do not meaningfully decrease insn_processed.
6403 if (sl
->miss_cnt
> sl
->hit_cnt
* 3 + 3) {
6404 /* the state is unlikely to be useful. Remove it to
6405 * speed up verification
6408 if (sl
->state
.frame
[0]->regs
[0].live
& REG_LIVE_DONE
) {
6409 free_verifier_state(&sl
->state
, false);
6413 /* cannot free this state, since parentage chain may
6414 * walk it later. Add it for free_list instead to
6415 * be freed at the end of verification
6417 sl
->next
= env
->free_list
;
6418 env
->free_list
= sl
;
6427 if (env
->max_states_per_insn
< states_cnt
)
6428 env
->max_states_per_insn
= states_cnt
;
6430 if (!env
->allow_ptr_leaks
&& states_cnt
> BPF_COMPLEXITY_LIMIT_STATES
)
6433 /* there were no equivalent states, remember current one.
6434 * technically the current state is not proven to be safe yet,
6435 * but it will either reach outer most bpf_exit (which means it's safe)
6436 * or it will be rejected. Since there are no loops, we won't be
6437 * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
6438 * again on the way to bpf_exit
6440 new_sl
= kzalloc(sizeof(struct bpf_verifier_state_list
), GFP_KERNEL
);
6443 env
->total_states
++;
6446 /* add new state to the head of linked list */
6447 new = &new_sl
->state
;
6448 err
= copy_verifier_state(new, cur
);
6450 free_verifier_state(new, false);
6454 new_sl
->next
= env
->explored_states
[insn_idx
];
6455 env
->explored_states
[insn_idx
] = new_sl
;
6456 /* connect new state to parentage chain. Current frame needs all
6457 * registers connected. Only r6 - r9 of the callers are alive (pushed
6458 * to the stack implicitly by JITs) so in callers' frames connect just
6459 * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
6460 * the state of the call instruction (with WRITTEN set), and r0 comes
6461 * from callee with its full parentage chain, anyway.
6463 for (j
= 0; j
<= cur
->curframe
; j
++)
6464 for (i
= j
< cur
->curframe
? BPF_REG_6
: 0; i
< BPF_REG_FP
; i
++)
6465 cur
->frame
[j
]->regs
[i
].parent
= &new->frame
[j
]->regs
[i
];
6466 /* clear write marks in current state: the writes we did are not writes
6467 * our child did, so they don't screen off its reads from us.
6468 * (There are no read marks in current state, because reads always mark
6469 * their parent and current state never has children yet. Only
6470 * explored_states can get read marks.)
6472 for (i
= 0; i
< BPF_REG_FP
; i
++)
6473 cur
->frame
[cur
->curframe
]->regs
[i
].live
= REG_LIVE_NONE
;
6475 /* all stack frames are accessible from callee, clear them all */
6476 for (j
= 0; j
<= cur
->curframe
; j
++) {
6477 struct bpf_func_state
*frame
= cur
->frame
[j
];
6478 struct bpf_func_state
*newframe
= new->frame
[j
];
6480 for (i
= 0; i
< frame
->allocated_stack
/ BPF_REG_SIZE
; i
++) {
6481 frame
->stack
[i
].spilled_ptr
.live
= REG_LIVE_NONE
;
6482 frame
->stack
[i
].spilled_ptr
.parent
=
6483 &newframe
->stack
[i
].spilled_ptr
;
6489 /* Return true if it's OK to have the same insn return a different type. */
6490 static bool reg_type_mismatch_ok(enum bpf_reg_type type
)
6495 case PTR_TO_SOCKET_OR_NULL
:
6496 case PTR_TO_SOCK_COMMON
:
6497 case PTR_TO_SOCK_COMMON_OR_NULL
:
6498 case PTR_TO_TCP_SOCK
:
6499 case PTR_TO_TCP_SOCK_OR_NULL
:
6506 /* If an instruction was previously used with particular pointer types, then we
6507 * need to be careful to avoid cases such as the below, where it may be ok
6508 * for one branch accessing the pointer, but not ok for the other branch:
6513 * R1 = some_other_valid_ptr;
6516 * R2 = *(u32 *)(R1 + 0);
6518 static bool reg_type_mismatch(enum bpf_reg_type src
, enum bpf_reg_type prev
)
6520 return src
!= prev
&& (!reg_type_mismatch_ok(src
) ||
6521 !reg_type_mismatch_ok(prev
));
6524 static int do_check(struct bpf_verifier_env
*env
)
6526 struct bpf_verifier_state
*state
;
6527 struct bpf_insn
*insns
= env
->prog
->insnsi
;
6528 struct bpf_reg_state
*regs
;
6529 int insn_cnt
= env
->prog
->len
;
6530 bool do_print_state
= false;
6532 env
->prev_linfo
= NULL
;
6534 state
= kzalloc(sizeof(struct bpf_verifier_state
), GFP_KERNEL
);
6537 state
->curframe
= 0;
6538 state
->speculative
= false;
6539 state
->frame
[0] = kzalloc(sizeof(struct bpf_func_state
), GFP_KERNEL
);
6540 if (!state
->frame
[0]) {
6544 env
->cur_state
= state
;
6545 init_func_state(env
, state
->frame
[0],
6546 BPF_MAIN_FUNC
/* callsite */,
6548 0 /* subprogno, zero == main subprog */);
6551 struct bpf_insn
*insn
;
6555 if (env
->insn_idx
>= insn_cnt
) {
6556 verbose(env
, "invalid insn idx %d insn_cnt %d\n",
6557 env
->insn_idx
, insn_cnt
);
6561 insn
= &insns
[env
->insn_idx
];
6562 class = BPF_CLASS(insn
->code
);
6564 if (++env
->insn_processed
> BPF_COMPLEXITY_LIMIT_INSNS
) {
6566 "BPF program is too large. Processed %d insn\n",
6567 env
->insn_processed
);
6571 err
= is_state_visited(env
, env
->insn_idx
);
6575 /* found equivalent state, can prune the search */
6576 if (env
->log
.level
& BPF_LOG_LEVEL
) {
6578 verbose(env
, "\nfrom %d to %d%s: safe\n",
6579 env
->prev_insn_idx
, env
->insn_idx
,
6580 env
->cur_state
->speculative
?
6581 " (speculative execution)" : "");
6583 verbose(env
, "%d: safe\n", env
->insn_idx
);
6585 goto process_bpf_exit
;
6588 if (signal_pending(current
))
6594 if (env
->log
.level
& BPF_LOG_LEVEL2
||
6595 (env
->log
.level
& BPF_LOG_LEVEL
&& do_print_state
)) {
6596 if (env
->log
.level
& BPF_LOG_LEVEL2
)
6597 verbose(env
, "%d:", env
->insn_idx
);
6599 verbose(env
, "\nfrom %d to %d%s:",
6600 env
->prev_insn_idx
, env
->insn_idx
,
6601 env
->cur_state
->speculative
?
6602 " (speculative execution)" : "");
6603 print_verifier_state(env
, state
->frame
[state
->curframe
]);
6604 do_print_state
= false;
6607 if (env
->log
.level
& BPF_LOG_LEVEL
) {
6608 const struct bpf_insn_cbs cbs
= {
6609 .cb_print
= verbose
,
6610 .private_data
= env
,
6613 verbose_linfo(env
, env
->insn_idx
, "; ");
6614 verbose(env
, "%d: ", env
->insn_idx
);
6615 print_bpf_insn(&cbs
, insn
, env
->allow_ptr_leaks
);
6618 if (bpf_prog_is_dev_bound(env
->prog
->aux
)) {
6619 err
= bpf_prog_offload_verify_insn(env
, env
->insn_idx
,
6620 env
->prev_insn_idx
);
6625 regs
= cur_regs(env
);
6626 env
->insn_aux_data
[env
->insn_idx
].seen
= true;
6628 if (class == BPF_ALU
|| class == BPF_ALU64
) {
6629 err
= check_alu_op(env
, insn
);
6633 } else if (class == BPF_LDX
) {
6634 enum bpf_reg_type
*prev_src_type
, src_reg_type
;
6636 /* check for reserved fields is already done */
6638 /* check src operand */
6639 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
6643 err
= check_reg_arg(env
, insn
->dst_reg
, DST_OP_NO_MARK
);
6647 src_reg_type
= regs
[insn
->src_reg
].type
;
6649 /* check that memory (src_reg + off) is readable,
6650 * the state of dst_reg will be updated by this func
6652 err
= check_mem_access(env
, env
->insn_idx
, insn
->src_reg
,
6653 insn
->off
, BPF_SIZE(insn
->code
),
6654 BPF_READ
, insn
->dst_reg
, false);
6658 prev_src_type
= &env
->insn_aux_data
[env
->insn_idx
].ptr_type
;
6660 if (*prev_src_type
== NOT_INIT
) {
6662 * dst_reg = *(u32 *)(src_reg + off)
6663 * save type to validate intersecting paths
6665 *prev_src_type
= src_reg_type
;
6667 } else if (reg_type_mismatch(src_reg_type
, *prev_src_type
)) {
6668 /* ABuser program is trying to use the same insn
6669 * dst_reg = *(u32*) (src_reg + off)
6670 * with different pointer types:
6671 * src_reg == ctx in one branch and
6672 * src_reg == stack|map in some other branch.
6675 verbose(env
, "same insn cannot be used with different pointers\n");
6679 } else if (class == BPF_STX
) {
6680 enum bpf_reg_type
*prev_dst_type
, dst_reg_type
;
6682 if (BPF_MODE(insn
->code
) == BPF_XADD
) {
6683 err
= check_xadd(env
, env
->insn_idx
, insn
);
6690 /* check src1 operand */
6691 err
= check_reg_arg(env
, insn
->src_reg
, SRC_OP
);
6694 /* check src2 operand */
6695 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
6699 dst_reg_type
= regs
[insn
->dst_reg
].type
;
6701 /* check that memory (dst_reg + off) is writeable */
6702 err
= check_mem_access(env
, env
->insn_idx
, insn
->dst_reg
,
6703 insn
->off
, BPF_SIZE(insn
->code
),
6704 BPF_WRITE
, insn
->src_reg
, false);
6708 prev_dst_type
= &env
->insn_aux_data
[env
->insn_idx
].ptr_type
;
6710 if (*prev_dst_type
== NOT_INIT
) {
6711 *prev_dst_type
= dst_reg_type
;
6712 } else if (reg_type_mismatch(dst_reg_type
, *prev_dst_type
)) {
6713 verbose(env
, "same insn cannot be used with different pointers\n");
6717 } else if (class == BPF_ST
) {
6718 if (BPF_MODE(insn
->code
) != BPF_MEM
||
6719 insn
->src_reg
!= BPF_REG_0
) {
6720 verbose(env
, "BPF_ST uses reserved fields\n");
6723 /* check src operand */
6724 err
= check_reg_arg(env
, insn
->dst_reg
, SRC_OP
);
6728 if (is_ctx_reg(env
, insn
->dst_reg
)) {
6729 verbose(env
, "BPF_ST stores into R%d %s is not allowed\n",
6731 reg_type_str
[reg_state(env
, insn
->dst_reg
)->type
]);
6735 /* check that memory (dst_reg + off) is writeable */
6736 err
= check_mem_access(env
, env
->insn_idx
, insn
->dst_reg
,
6737 insn
->off
, BPF_SIZE(insn
->code
),
6738 BPF_WRITE
, -1, false);
6742 } else if (class == BPF_JMP
|| class == BPF_JMP32
) {
6743 u8 opcode
= BPF_OP(insn
->code
);
6745 if (opcode
== BPF_CALL
) {
6746 if (BPF_SRC(insn
->code
) != BPF_K
||
6748 (insn
->src_reg
!= BPF_REG_0
&&
6749 insn
->src_reg
!= BPF_PSEUDO_CALL
) ||
6750 insn
->dst_reg
!= BPF_REG_0
||
6751 class == BPF_JMP32
) {
6752 verbose(env
, "BPF_CALL uses reserved fields\n");
6756 if (env
->cur_state
->active_spin_lock
&&
6757 (insn
->src_reg
== BPF_PSEUDO_CALL
||
6758 insn
->imm
!= BPF_FUNC_spin_unlock
)) {
6759 verbose(env
, "function calls are not allowed while holding a lock\n");
6762 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
6763 err
= check_func_call(env
, insn
, &env
->insn_idx
);
6765 err
= check_helper_call(env
, insn
->imm
, env
->insn_idx
);
6769 } else if (opcode
== BPF_JA
) {
6770 if (BPF_SRC(insn
->code
) != BPF_K
||
6772 insn
->src_reg
!= BPF_REG_0
||
6773 insn
->dst_reg
!= BPF_REG_0
||
6774 class == BPF_JMP32
) {
6775 verbose(env
, "BPF_JA uses reserved fields\n");
6779 env
->insn_idx
+= insn
->off
+ 1;
6782 } else if (opcode
== BPF_EXIT
) {
6783 if (BPF_SRC(insn
->code
) != BPF_K
||
6785 insn
->src_reg
!= BPF_REG_0
||
6786 insn
->dst_reg
!= BPF_REG_0
||
6787 class == BPF_JMP32
) {
6788 verbose(env
, "BPF_EXIT uses reserved fields\n");
6792 if (env
->cur_state
->active_spin_lock
) {
6793 verbose(env
, "bpf_spin_unlock is missing\n");
6797 if (state
->curframe
) {
6798 /* exit from nested function */
6799 env
->prev_insn_idx
= env
->insn_idx
;
6800 err
= prepare_func_exit(env
, &env
->insn_idx
);
6803 do_print_state
= true;
6807 err
= check_reference_leak(env
);
6811 /* eBPF calling convetion is such that R0 is used
6812 * to return the value from eBPF program.
6813 * Make sure that it's readable at this time
6814 * of bpf_exit, which means that program wrote
6815 * something into it earlier
6817 err
= check_reg_arg(env
, BPF_REG_0
, SRC_OP
);
6821 if (is_pointer_value(env
, BPF_REG_0
)) {
6822 verbose(env
, "R0 leaks addr as return value\n");
6826 err
= check_return_code(env
);
6830 err
= pop_stack(env
, &env
->prev_insn_idx
,
6837 do_print_state
= true;
6841 err
= check_cond_jmp_op(env
, insn
, &env
->insn_idx
);
6845 } else if (class == BPF_LD
) {
6846 u8 mode
= BPF_MODE(insn
->code
);
6848 if (mode
== BPF_ABS
|| mode
== BPF_IND
) {
6849 err
= check_ld_abs(env
, insn
);
6853 } else if (mode
== BPF_IMM
) {
6854 err
= check_ld_imm(env
, insn
);
6859 env
->insn_aux_data
[env
->insn_idx
].seen
= true;
6861 verbose(env
, "invalid BPF_LD mode\n");
6865 verbose(env
, "unknown insn class %d\n", class);
6872 env
->prog
->aux
->stack_depth
= env
->subprog_info
[0].stack_depth
;
6876 static int check_map_prealloc(struct bpf_map
*map
)
6878 return (map
->map_type
!= BPF_MAP_TYPE_HASH
&&
6879 map
->map_type
!= BPF_MAP_TYPE_PERCPU_HASH
&&
6880 map
->map_type
!= BPF_MAP_TYPE_HASH_OF_MAPS
) ||
6881 !(map
->map_flags
& BPF_F_NO_PREALLOC
);
6884 static bool is_tracing_prog_type(enum bpf_prog_type type
)
6887 case BPF_PROG_TYPE_KPROBE
:
6888 case BPF_PROG_TYPE_TRACEPOINT
:
6889 case BPF_PROG_TYPE_PERF_EVENT
:
6890 case BPF_PROG_TYPE_RAW_TRACEPOINT
:
6897 static int check_map_prog_compatibility(struct bpf_verifier_env
*env
,
6898 struct bpf_map
*map
,
6899 struct bpf_prog
*prog
)
6902 /* Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use
6903 * preallocated hash maps, since doing memory allocation
6904 * in overflow_handler can crash depending on where nmi got
6907 if (prog
->type
== BPF_PROG_TYPE_PERF_EVENT
) {
6908 if (!check_map_prealloc(map
)) {
6909 verbose(env
, "perf_event programs can only use preallocated hash map\n");
6912 if (map
->inner_map_meta
&&
6913 !check_map_prealloc(map
->inner_map_meta
)) {
6914 verbose(env
, "perf_event programs can only use preallocated inner hash map\n");
6919 if ((is_tracing_prog_type(prog
->type
) ||
6920 prog
->type
== BPF_PROG_TYPE_SOCKET_FILTER
) &&
6921 map_value_has_spin_lock(map
)) {
6922 verbose(env
, "tracing progs cannot use bpf_spin_lock yet\n");
6926 if ((bpf_prog_is_dev_bound(prog
->aux
) || bpf_map_is_dev_bound(map
)) &&
6927 !bpf_offload_prog_map_match(prog
, map
)) {
6928 verbose(env
, "offload device mismatch between prog and map\n");
6935 static bool bpf_map_is_cgroup_storage(struct bpf_map
*map
)
6937 return (map
->map_type
== BPF_MAP_TYPE_CGROUP_STORAGE
||
6938 map
->map_type
== BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
);
6941 /* look for pseudo eBPF instructions that access map FDs and
6942 * replace them with actual map pointers
6944 static int replace_map_fd_with_map_ptr(struct bpf_verifier_env
*env
)
6946 struct bpf_insn
*insn
= env
->prog
->insnsi
;
6947 int insn_cnt
= env
->prog
->len
;
6950 err
= bpf_prog_calc_tag(env
->prog
);
6954 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
6955 if (BPF_CLASS(insn
->code
) == BPF_LDX
&&
6956 (BPF_MODE(insn
->code
) != BPF_MEM
|| insn
->imm
!= 0)) {
6957 verbose(env
, "BPF_LDX uses reserved fields\n");
6961 if (BPF_CLASS(insn
->code
) == BPF_STX
&&
6962 ((BPF_MODE(insn
->code
) != BPF_MEM
&&
6963 BPF_MODE(insn
->code
) != BPF_XADD
) || insn
->imm
!= 0)) {
6964 verbose(env
, "BPF_STX uses reserved fields\n");
6968 if (insn
[0].code
== (BPF_LD
| BPF_IMM
| BPF_DW
)) {
6969 struct bpf_insn_aux_data
*aux
;
6970 struct bpf_map
*map
;
6974 if (i
== insn_cnt
- 1 || insn
[1].code
!= 0 ||
6975 insn
[1].dst_reg
!= 0 || insn
[1].src_reg
!= 0 ||
6977 verbose(env
, "invalid bpf_ld_imm64 insn\n");
6981 if (insn
[0].src_reg
== 0)
6982 /* valid generic load 64-bit imm */
6985 /* In final convert_pseudo_ld_imm64() step, this is
6986 * converted into regular 64-bit imm load insn.
6988 if ((insn
[0].src_reg
!= BPF_PSEUDO_MAP_FD
&&
6989 insn
[0].src_reg
!= BPF_PSEUDO_MAP_VALUE
) ||
6990 (insn
[0].src_reg
== BPF_PSEUDO_MAP_FD
&&
6991 insn
[1].imm
!= 0)) {
6993 "unrecognized bpf_ld_imm64 insn\n");
6997 f
= fdget(insn
[0].imm
);
6998 map
= __bpf_map_get(f
);
7000 verbose(env
, "fd %d is not pointing to valid bpf_map\n",
7002 return PTR_ERR(map
);
7005 err
= check_map_prog_compatibility(env
, map
, env
->prog
);
7011 aux
= &env
->insn_aux_data
[i
];
7012 if (insn
->src_reg
== BPF_PSEUDO_MAP_FD
) {
7013 addr
= (unsigned long)map
;
7015 u32 off
= insn
[1].imm
;
7017 if (off
>= BPF_MAX_VAR_OFF
) {
7018 verbose(env
, "direct value offset of %u is not allowed\n", off
);
7023 if (!map
->ops
->map_direct_value_addr
) {
7024 verbose(env
, "no direct value access support for this map type\n");
7029 err
= map
->ops
->map_direct_value_addr(map
, &addr
, off
);
7031 verbose(env
, "invalid access to map value pointer, value_size=%u off=%u\n",
7032 map
->value_size
, off
);
7041 insn
[0].imm
= (u32
)addr
;
7042 insn
[1].imm
= addr
>> 32;
7044 /* check whether we recorded this map already */
7045 for (j
= 0; j
< env
->used_map_cnt
; j
++) {
7046 if (env
->used_maps
[j
] == map
) {
7053 if (env
->used_map_cnt
>= MAX_USED_MAPS
) {
7058 /* hold the map. If the program is rejected by verifier,
7059 * the map will be released by release_maps() or it
7060 * will be used by the valid program until it's unloaded
7061 * and all maps are released in free_used_maps()
7063 map
= bpf_map_inc(map
, false);
7066 return PTR_ERR(map
);
7069 aux
->map_index
= env
->used_map_cnt
;
7070 env
->used_maps
[env
->used_map_cnt
++] = map
;
7072 if (bpf_map_is_cgroup_storage(map
) &&
7073 bpf_cgroup_storage_assign(env
->prog
, map
)) {
7074 verbose(env
, "only one cgroup storage of each type is allowed\n");
7086 /* Basic sanity check before we invest more work here. */
7087 if (!bpf_opcode_in_insntable(insn
->code
)) {
7088 verbose(env
, "unknown opcode %02x\n", insn
->code
);
7093 /* now all pseudo BPF_LD_IMM64 instructions load valid
7094 * 'struct bpf_map *' into a register instead of user map_fd.
7095 * These pointers will be used later by verifier to validate map access.
7100 /* drop refcnt of maps used by the rejected program */
7101 static void release_maps(struct bpf_verifier_env
*env
)
7103 enum bpf_cgroup_storage_type stype
;
7106 for_each_cgroup_storage_type(stype
) {
7107 if (!env
->prog
->aux
->cgroup_storage
[stype
])
7109 bpf_cgroup_storage_release(env
->prog
,
7110 env
->prog
->aux
->cgroup_storage
[stype
]);
7113 for (i
= 0; i
< env
->used_map_cnt
; i
++)
7114 bpf_map_put(env
->used_maps
[i
]);
7117 /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
7118 static void convert_pseudo_ld_imm64(struct bpf_verifier_env
*env
)
7120 struct bpf_insn
*insn
= env
->prog
->insnsi
;
7121 int insn_cnt
= env
->prog
->len
;
7124 for (i
= 0; i
< insn_cnt
; i
++, insn
++)
7125 if (insn
->code
== (BPF_LD
| BPF_IMM
| BPF_DW
))
7129 /* single env->prog->insni[off] instruction was replaced with the range
7130 * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying
7131 * [0, off) and [off, end) to new locations, so the patched range stays zero
7133 static int adjust_insn_aux_data(struct bpf_verifier_env
*env
, u32 prog_len
,
7136 struct bpf_insn_aux_data
*new_data
, *old_data
= env
->insn_aux_data
;
7141 new_data
= vzalloc(array_size(prog_len
,
7142 sizeof(struct bpf_insn_aux_data
)));
7145 memcpy(new_data
, old_data
, sizeof(struct bpf_insn_aux_data
) * off
);
7146 memcpy(new_data
+ off
+ cnt
- 1, old_data
+ off
,
7147 sizeof(struct bpf_insn_aux_data
) * (prog_len
- off
- cnt
+ 1));
7148 for (i
= off
; i
< off
+ cnt
- 1; i
++)
7149 new_data
[i
].seen
= true;
7150 env
->insn_aux_data
= new_data
;
7155 static void adjust_subprog_starts(struct bpf_verifier_env
*env
, u32 off
, u32 len
)
7161 /* NOTE: fake 'exit' subprog should be updated as well. */
7162 for (i
= 0; i
<= env
->subprog_cnt
; i
++) {
7163 if (env
->subprog_info
[i
].start
<= off
)
7165 env
->subprog_info
[i
].start
+= len
- 1;
7169 static struct bpf_prog
*bpf_patch_insn_data(struct bpf_verifier_env
*env
, u32 off
,
7170 const struct bpf_insn
*patch
, u32 len
)
7172 struct bpf_prog
*new_prog
;
7174 new_prog
= bpf_patch_insn_single(env
->prog
, off
, patch
, len
);
7175 if (IS_ERR(new_prog
)) {
7176 if (PTR_ERR(new_prog
) == -ERANGE
)
7178 "insn %d cannot be patched due to 16-bit range\n",
7179 env
->insn_aux_data
[off
].orig_idx
);
7182 if (adjust_insn_aux_data(env
, new_prog
->len
, off
, len
))
7184 adjust_subprog_starts(env
, off
, len
);
7188 static int adjust_subprog_starts_after_remove(struct bpf_verifier_env
*env
,
7193 /* find first prog starting at or after off (first to remove) */
7194 for (i
= 0; i
< env
->subprog_cnt
; i
++)
7195 if (env
->subprog_info
[i
].start
>= off
)
7197 /* find first prog starting at or after off + cnt (first to stay) */
7198 for (j
= i
; j
< env
->subprog_cnt
; j
++)
7199 if (env
->subprog_info
[j
].start
>= off
+ cnt
)
7201 /* if j doesn't start exactly at off + cnt, we are just removing
7202 * the front of previous prog
7204 if (env
->subprog_info
[j
].start
!= off
+ cnt
)
7208 struct bpf_prog_aux
*aux
= env
->prog
->aux
;
7211 /* move fake 'exit' subprog as well */
7212 move
= env
->subprog_cnt
+ 1 - j
;
7214 memmove(env
->subprog_info
+ i
,
7215 env
->subprog_info
+ j
,
7216 sizeof(*env
->subprog_info
) * move
);
7217 env
->subprog_cnt
-= j
- i
;
7219 /* remove func_info */
7220 if (aux
->func_info
) {
7221 move
= aux
->func_info_cnt
- j
;
7223 memmove(aux
->func_info
+ i
,
7225 sizeof(*aux
->func_info
) * move
);
7226 aux
->func_info_cnt
-= j
- i
;
7227 /* func_info->insn_off is set after all code rewrites,
7228 * in adjust_btf_func() - no need to adjust
7232 /* convert i from "first prog to remove" to "first to adjust" */
7233 if (env
->subprog_info
[i
].start
== off
)
7237 /* update fake 'exit' subprog as well */
7238 for (; i
<= env
->subprog_cnt
; i
++)
7239 env
->subprog_info
[i
].start
-= cnt
;
7244 static int bpf_adj_linfo_after_remove(struct bpf_verifier_env
*env
, u32 off
,
7247 struct bpf_prog
*prog
= env
->prog
;
7248 u32 i
, l_off
, l_cnt
, nr_linfo
;
7249 struct bpf_line_info
*linfo
;
7251 nr_linfo
= prog
->aux
->nr_linfo
;
7255 linfo
= prog
->aux
->linfo
;
7257 /* find first line info to remove, count lines to be removed */
7258 for (i
= 0; i
< nr_linfo
; i
++)
7259 if (linfo
[i
].insn_off
>= off
)
7264 for (; i
< nr_linfo
; i
++)
7265 if (linfo
[i
].insn_off
< off
+ cnt
)
7270 /* First live insn doesn't match first live linfo, it needs to "inherit"
7271 * last removed linfo. prog is already modified, so prog->len == off
7272 * means no live instructions after (tail of the program was removed).
7274 if (prog
->len
!= off
&& l_cnt
&&
7275 (i
== nr_linfo
|| linfo
[i
].insn_off
!= off
+ cnt
)) {
7277 linfo
[--i
].insn_off
= off
+ cnt
;
7280 /* remove the line info which refer to the removed instructions */
7282 memmove(linfo
+ l_off
, linfo
+ i
,
7283 sizeof(*linfo
) * (nr_linfo
- i
));
7285 prog
->aux
->nr_linfo
-= l_cnt
;
7286 nr_linfo
= prog
->aux
->nr_linfo
;
7289 /* pull all linfo[i].insn_off >= off + cnt in by cnt */
7290 for (i
= l_off
; i
< nr_linfo
; i
++)
7291 linfo
[i
].insn_off
-= cnt
;
7293 /* fix up all subprogs (incl. 'exit') which start >= off */
7294 for (i
= 0; i
<= env
->subprog_cnt
; i
++)
7295 if (env
->subprog_info
[i
].linfo_idx
> l_off
) {
7296 /* program may have started in the removed region but
7297 * may not be fully removed
7299 if (env
->subprog_info
[i
].linfo_idx
>= l_off
+ l_cnt
)
7300 env
->subprog_info
[i
].linfo_idx
-= l_cnt
;
7302 env
->subprog_info
[i
].linfo_idx
= l_off
;
7308 static int verifier_remove_insns(struct bpf_verifier_env
*env
, u32 off
, u32 cnt
)
7310 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
7311 unsigned int orig_prog_len
= env
->prog
->len
;
7314 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
7315 bpf_prog_offload_remove_insns(env
, off
, cnt
);
7317 err
= bpf_remove_insns(env
->prog
, off
, cnt
);
7321 err
= adjust_subprog_starts_after_remove(env
, off
, cnt
);
7325 err
= bpf_adj_linfo_after_remove(env
, off
, cnt
);
7329 memmove(aux_data
+ off
, aux_data
+ off
+ cnt
,
7330 sizeof(*aux_data
) * (orig_prog_len
- off
- cnt
));
7335 /* The verifier does more data flow analysis than llvm and will not
7336 * explore branches that are dead at run time. Malicious programs can
7337 * have dead code too. Therefore replace all dead at-run-time code
7340 * Just nops are not optimal, e.g. if they would sit at the end of the
7341 * program and through another bug we would manage to jump there, then
7342 * we'd execute beyond program memory otherwise. Returning exception
7343 * code also wouldn't work since we can have subprogs where the dead
7344 * code could be located.
7346 static void sanitize_dead_code(struct bpf_verifier_env
*env
)
7348 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
7349 struct bpf_insn trap
= BPF_JMP_IMM(BPF_JA
, 0, 0, -1);
7350 struct bpf_insn
*insn
= env
->prog
->insnsi
;
7351 const int insn_cnt
= env
->prog
->len
;
7354 for (i
= 0; i
< insn_cnt
; i
++) {
7355 if (aux_data
[i
].seen
)
7357 memcpy(insn
+ i
, &trap
, sizeof(trap
));
7361 static bool insn_is_cond_jump(u8 code
)
7365 if (BPF_CLASS(code
) == BPF_JMP32
)
7368 if (BPF_CLASS(code
) != BPF_JMP
)
7372 return op
!= BPF_JA
&& op
!= BPF_EXIT
&& op
!= BPF_CALL
;
7375 static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env
*env
)
7377 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
7378 struct bpf_insn ja
= BPF_JMP_IMM(BPF_JA
, 0, 0, 0);
7379 struct bpf_insn
*insn
= env
->prog
->insnsi
;
7380 const int insn_cnt
= env
->prog
->len
;
7383 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
7384 if (!insn_is_cond_jump(insn
->code
))
7387 if (!aux_data
[i
+ 1].seen
)
7389 else if (!aux_data
[i
+ 1 + insn
->off
].seen
)
7394 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
7395 bpf_prog_offload_replace_insn(env
, i
, &ja
);
7397 memcpy(insn
, &ja
, sizeof(ja
));
7401 static int opt_remove_dead_code(struct bpf_verifier_env
*env
)
7403 struct bpf_insn_aux_data
*aux_data
= env
->insn_aux_data
;
7404 int insn_cnt
= env
->prog
->len
;
7407 for (i
= 0; i
< insn_cnt
; i
++) {
7411 while (i
+ j
< insn_cnt
&& !aux_data
[i
+ j
].seen
)
7416 err
= verifier_remove_insns(env
, i
, j
);
7419 insn_cnt
= env
->prog
->len
;
7425 static int opt_remove_nops(struct bpf_verifier_env
*env
)
7427 const struct bpf_insn ja
= BPF_JMP_IMM(BPF_JA
, 0, 0, 0);
7428 struct bpf_insn
*insn
= env
->prog
->insnsi
;
7429 int insn_cnt
= env
->prog
->len
;
7432 for (i
= 0; i
< insn_cnt
; i
++) {
7433 if (memcmp(&insn
[i
], &ja
, sizeof(ja
)))
7436 err
= verifier_remove_insns(env
, i
, 1);
7446 /* convert load instructions that access fields of a context type into a
7447 * sequence of instructions that access fields of the underlying structure:
7448 * struct __sk_buff -> struct sk_buff
7449 * struct bpf_sock_ops -> struct sock
7451 static int convert_ctx_accesses(struct bpf_verifier_env
*env
)
7453 const struct bpf_verifier_ops
*ops
= env
->ops
;
7454 int i
, cnt
, size
, ctx_field_size
, delta
= 0;
7455 const int insn_cnt
= env
->prog
->len
;
7456 struct bpf_insn insn_buf
[16], *insn
;
7457 u32 target_size
, size_default
, off
;
7458 struct bpf_prog
*new_prog
;
7459 enum bpf_access_type type
;
7460 bool is_narrower_load
;
7462 if (ops
->gen_prologue
|| env
->seen_direct_write
) {
7463 if (!ops
->gen_prologue
) {
7464 verbose(env
, "bpf verifier is misconfigured\n");
7467 cnt
= ops
->gen_prologue(insn_buf
, env
->seen_direct_write
,
7469 if (cnt
>= ARRAY_SIZE(insn_buf
)) {
7470 verbose(env
, "bpf verifier is misconfigured\n");
7473 new_prog
= bpf_patch_insn_data(env
, 0, insn_buf
, cnt
);
7477 env
->prog
= new_prog
;
7482 if (bpf_prog_is_dev_bound(env
->prog
->aux
))
7485 insn
= env
->prog
->insnsi
+ delta
;
7487 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
7488 bpf_convert_ctx_access_t convert_ctx_access
;
7490 if (insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_B
) ||
7491 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_H
) ||
7492 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_W
) ||
7493 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_DW
))
7495 else if (insn
->code
== (BPF_STX
| BPF_MEM
| BPF_B
) ||
7496 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_H
) ||
7497 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_W
) ||
7498 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_DW
))
7503 if (type
== BPF_WRITE
&&
7504 env
->insn_aux_data
[i
+ delta
].sanitize_stack_off
) {
7505 struct bpf_insn patch
[] = {
7506 /* Sanitize suspicious stack slot with zero.
7507 * There are no memory dependencies for this store,
7508 * since it's only using frame pointer and immediate
7511 BPF_ST_MEM(BPF_DW
, BPF_REG_FP
,
7512 env
->insn_aux_data
[i
+ delta
].sanitize_stack_off
,
7514 /* the original STX instruction will immediately
7515 * overwrite the same stack slot with appropriate value
7520 cnt
= ARRAY_SIZE(patch
);
7521 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, patch
, cnt
);
7526 env
->prog
= new_prog
;
7527 insn
= new_prog
->insnsi
+ i
+ delta
;
7531 switch (env
->insn_aux_data
[i
+ delta
].ptr_type
) {
7533 if (!ops
->convert_ctx_access
)
7535 convert_ctx_access
= ops
->convert_ctx_access
;
7538 case PTR_TO_SOCK_COMMON
:
7539 convert_ctx_access
= bpf_sock_convert_ctx_access
;
7541 case PTR_TO_TCP_SOCK
:
7542 convert_ctx_access
= bpf_tcp_sock_convert_ctx_access
;
7548 ctx_field_size
= env
->insn_aux_data
[i
+ delta
].ctx_field_size
;
7549 size
= BPF_LDST_BYTES(insn
);
7551 /* If the read access is a narrower load of the field,
7552 * convert to a 4/8-byte load, to minimum program type specific
7553 * convert_ctx_access changes. If conversion is successful,
7554 * we will apply proper mask to the result.
7556 is_narrower_load
= size
< ctx_field_size
;
7557 size_default
= bpf_ctx_off_adjust_machine(ctx_field_size
);
7559 if (is_narrower_load
) {
7562 if (type
== BPF_WRITE
) {
7563 verbose(env
, "bpf verifier narrow ctx access misconfigured\n");
7568 if (ctx_field_size
== 4)
7570 else if (ctx_field_size
== 8)
7573 insn
->off
= off
& ~(size_default
- 1);
7574 insn
->code
= BPF_LDX
| BPF_MEM
| size_code
;
7578 cnt
= convert_ctx_access(type
, insn
, insn_buf
, env
->prog
,
7580 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
) ||
7581 (ctx_field_size
&& !target_size
)) {
7582 verbose(env
, "bpf verifier is misconfigured\n");
7586 if (is_narrower_load
&& size
< target_size
) {
7587 u8 shift
= (off
& (size_default
- 1)) * 8;
7589 if (ctx_field_size
<= 4) {
7591 insn_buf
[cnt
++] = BPF_ALU32_IMM(BPF_RSH
,
7594 insn_buf
[cnt
++] = BPF_ALU32_IMM(BPF_AND
, insn
->dst_reg
,
7595 (1 << size
* 8) - 1);
7598 insn_buf
[cnt
++] = BPF_ALU64_IMM(BPF_RSH
,
7601 insn_buf
[cnt
++] = BPF_ALU64_IMM(BPF_AND
, insn
->dst_reg
,
7602 (1ULL << size
* 8) - 1);
7606 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
7612 /* keep walking new program and skip insns we just inserted */
7613 env
->prog
= new_prog
;
7614 insn
= new_prog
->insnsi
+ i
+ delta
;
7620 static int jit_subprogs(struct bpf_verifier_env
*env
)
7622 struct bpf_prog
*prog
= env
->prog
, **func
, *tmp
;
7623 int i
, j
, subprog_start
, subprog_end
= 0, len
, subprog
;
7624 struct bpf_insn
*insn
;
7628 if (env
->subprog_cnt
<= 1)
7631 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
7632 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
7633 insn
->src_reg
!= BPF_PSEUDO_CALL
)
7635 /* Upon error here we cannot fall back to interpreter but
7636 * need a hard reject of the program. Thus -EFAULT is
7637 * propagated in any case.
7639 subprog
= find_subprog(env
, i
+ insn
->imm
+ 1);
7641 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
7645 /* temporarily remember subprog id inside insn instead of
7646 * aux_data, since next loop will split up all insns into funcs
7648 insn
->off
= subprog
;
7649 /* remember original imm in case JIT fails and fallback
7650 * to interpreter will be needed
7652 env
->insn_aux_data
[i
].call_imm
= insn
->imm
;
7653 /* point imm to __bpf_call_base+1 from JITs point of view */
7657 err
= bpf_prog_alloc_jited_linfo(prog
);
7662 func
= kcalloc(env
->subprog_cnt
, sizeof(prog
), GFP_KERNEL
);
7666 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
7667 subprog_start
= subprog_end
;
7668 subprog_end
= env
->subprog_info
[i
+ 1].start
;
7670 len
= subprog_end
- subprog_start
;
7671 /* BPF_PROG_RUN doesn't call subprogs directly,
7672 * hence main prog stats include the runtime of subprogs.
7673 * subprogs don't have IDs and not reachable via prog_get_next_id
7674 * func[i]->aux->stats will never be accessed and stays NULL
7676 func
[i
] = bpf_prog_alloc_no_stats(bpf_prog_size(len
), GFP_USER
);
7679 memcpy(func
[i
]->insnsi
, &prog
->insnsi
[subprog_start
],
7680 len
* sizeof(struct bpf_insn
));
7681 func
[i
]->type
= prog
->type
;
7683 if (bpf_prog_calc_tag(func
[i
]))
7685 func
[i
]->is_func
= 1;
7686 func
[i
]->aux
->func_idx
= i
;
7687 /* the btf and func_info will be freed only at prog->aux */
7688 func
[i
]->aux
->btf
= prog
->aux
->btf
;
7689 func
[i
]->aux
->func_info
= prog
->aux
->func_info
;
7691 /* Use bpf_prog_F_tag to indicate functions in stack traces.
7692 * Long term would need debug info to populate names
7694 func
[i
]->aux
->name
[0] = 'F';
7695 func
[i
]->aux
->stack_depth
= env
->subprog_info
[i
].stack_depth
;
7696 func
[i
]->jit_requested
= 1;
7697 func
[i
]->aux
->linfo
= prog
->aux
->linfo
;
7698 func
[i
]->aux
->nr_linfo
= prog
->aux
->nr_linfo
;
7699 func
[i
]->aux
->jited_linfo
= prog
->aux
->jited_linfo
;
7700 func
[i
]->aux
->linfo_idx
= env
->subprog_info
[i
].linfo_idx
;
7701 func
[i
] = bpf_int_jit_compile(func
[i
]);
7702 if (!func
[i
]->jited
) {
7708 /* at this point all bpf functions were successfully JITed
7709 * now populate all bpf_calls with correct addresses and
7710 * run last pass of JIT
7712 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
7713 insn
= func
[i
]->insnsi
;
7714 for (j
= 0; j
< func
[i
]->len
; j
++, insn
++) {
7715 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
7716 insn
->src_reg
!= BPF_PSEUDO_CALL
)
7718 subprog
= insn
->off
;
7719 insn
->imm
= BPF_CAST_CALL(func
[subprog
]->bpf_func
) -
7723 /* we use the aux data to keep a list of the start addresses
7724 * of the JITed images for each function in the program
7726 * for some architectures, such as powerpc64, the imm field
7727 * might not be large enough to hold the offset of the start
7728 * address of the callee's JITed image from __bpf_call_base
7730 * in such cases, we can lookup the start address of a callee
7731 * by using its subprog id, available from the off field of
7732 * the call instruction, as an index for this list
7734 func
[i
]->aux
->func
= func
;
7735 func
[i
]->aux
->func_cnt
= env
->subprog_cnt
;
7737 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
7738 old_bpf_func
= func
[i
]->bpf_func
;
7739 tmp
= bpf_int_jit_compile(func
[i
]);
7740 if (tmp
!= func
[i
] || func
[i
]->bpf_func
!= old_bpf_func
) {
7741 verbose(env
, "JIT doesn't support bpf-to-bpf calls\n");
7748 /* finally lock prog and jit images for all functions and
7751 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
7752 bpf_prog_lock_ro(func
[i
]);
7753 bpf_prog_kallsyms_add(func
[i
]);
7756 /* Last step: make now unused interpreter insns from main
7757 * prog consistent for later dump requests, so they can
7758 * later look the same as if they were interpreted only.
7760 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
7761 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
7762 insn
->src_reg
!= BPF_PSEUDO_CALL
)
7764 insn
->off
= env
->insn_aux_data
[i
].call_imm
;
7765 subprog
= find_subprog(env
, i
+ insn
->off
+ 1);
7766 insn
->imm
= subprog
;
7770 prog
->bpf_func
= func
[0]->bpf_func
;
7771 prog
->aux
->func
= func
;
7772 prog
->aux
->func_cnt
= env
->subprog_cnt
;
7773 bpf_prog_free_unused_jited_linfo(prog
);
7776 for (i
= 0; i
< env
->subprog_cnt
; i
++)
7778 bpf_jit_free(func
[i
]);
7781 /* cleanup main prog to be interpreted */
7782 prog
->jit_requested
= 0;
7783 for (i
= 0, insn
= prog
->insnsi
; i
< prog
->len
; i
++, insn
++) {
7784 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
7785 insn
->src_reg
!= BPF_PSEUDO_CALL
)
7788 insn
->imm
= env
->insn_aux_data
[i
].call_imm
;
7790 bpf_prog_free_jited_linfo(prog
);
7794 static int fixup_call_args(struct bpf_verifier_env
*env
)
7796 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
7797 struct bpf_prog
*prog
= env
->prog
;
7798 struct bpf_insn
*insn
= prog
->insnsi
;
7803 if (env
->prog
->jit_requested
&&
7804 !bpf_prog_is_dev_bound(env
->prog
->aux
)) {
7805 err
= jit_subprogs(env
);
7811 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
7812 for (i
= 0; i
< prog
->len
; i
++, insn
++) {
7813 if (insn
->code
!= (BPF_JMP
| BPF_CALL
) ||
7814 insn
->src_reg
!= BPF_PSEUDO_CALL
)
7816 depth
= get_callee_stack_depth(env
, insn
, i
);
7819 bpf_patch_call_args(insn
, depth
);
7826 /* fixup insn->imm field of bpf_call instructions
7827 * and inline eligible helpers as explicit sequence of BPF instructions
7829 * this function is called after eBPF program passed verification
7831 static int fixup_bpf_calls(struct bpf_verifier_env
*env
)
7833 struct bpf_prog
*prog
= env
->prog
;
7834 struct bpf_insn
*insn
= prog
->insnsi
;
7835 const struct bpf_func_proto
*fn
;
7836 const int insn_cnt
= prog
->len
;
7837 const struct bpf_map_ops
*ops
;
7838 struct bpf_insn_aux_data
*aux
;
7839 struct bpf_insn insn_buf
[16];
7840 struct bpf_prog
*new_prog
;
7841 struct bpf_map
*map_ptr
;
7842 int i
, cnt
, delta
= 0;
7844 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
7845 if (insn
->code
== (BPF_ALU64
| BPF_MOD
| BPF_X
) ||
7846 insn
->code
== (BPF_ALU64
| BPF_DIV
| BPF_X
) ||
7847 insn
->code
== (BPF_ALU
| BPF_MOD
| BPF_X
) ||
7848 insn
->code
== (BPF_ALU
| BPF_DIV
| BPF_X
)) {
7849 bool is64
= BPF_CLASS(insn
->code
) == BPF_ALU64
;
7850 struct bpf_insn mask_and_div
[] = {
7851 BPF_MOV32_REG(insn
->src_reg
, insn
->src_reg
),
7853 BPF_JMP_IMM(BPF_JNE
, insn
->src_reg
, 0, 2),
7854 BPF_ALU32_REG(BPF_XOR
, insn
->dst_reg
, insn
->dst_reg
),
7855 BPF_JMP_IMM(BPF_JA
, 0, 0, 1),
7858 struct bpf_insn mask_and_mod
[] = {
7859 BPF_MOV32_REG(insn
->src_reg
, insn
->src_reg
),
7860 /* Rx mod 0 -> Rx */
7861 BPF_JMP_IMM(BPF_JEQ
, insn
->src_reg
, 0, 1),
7864 struct bpf_insn
*patchlet
;
7866 if (insn
->code
== (BPF_ALU64
| BPF_DIV
| BPF_X
) ||
7867 insn
->code
== (BPF_ALU
| BPF_DIV
| BPF_X
)) {
7868 patchlet
= mask_and_div
+ (is64
? 1 : 0);
7869 cnt
= ARRAY_SIZE(mask_and_div
) - (is64
? 1 : 0);
7871 patchlet
= mask_and_mod
+ (is64
? 1 : 0);
7872 cnt
= ARRAY_SIZE(mask_and_mod
) - (is64
? 1 : 0);
7875 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, patchlet
, cnt
);
7880 env
->prog
= prog
= new_prog
;
7881 insn
= new_prog
->insnsi
+ i
+ delta
;
7885 if (BPF_CLASS(insn
->code
) == BPF_LD
&&
7886 (BPF_MODE(insn
->code
) == BPF_ABS
||
7887 BPF_MODE(insn
->code
) == BPF_IND
)) {
7888 cnt
= env
->ops
->gen_ld_abs(insn
, insn_buf
);
7889 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
)) {
7890 verbose(env
, "bpf verifier is misconfigured\n");
7894 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
7899 env
->prog
= prog
= new_prog
;
7900 insn
= new_prog
->insnsi
+ i
+ delta
;
7904 if (insn
->code
== (BPF_ALU64
| BPF_ADD
| BPF_X
) ||
7905 insn
->code
== (BPF_ALU64
| BPF_SUB
| BPF_X
)) {
7906 const u8 code_add
= BPF_ALU64
| BPF_ADD
| BPF_X
;
7907 const u8 code_sub
= BPF_ALU64
| BPF_SUB
| BPF_X
;
7908 struct bpf_insn insn_buf
[16];
7909 struct bpf_insn
*patch
= &insn_buf
[0];
7913 aux
= &env
->insn_aux_data
[i
+ delta
];
7914 if (!aux
->alu_state
||
7915 aux
->alu_state
== BPF_ALU_NON_POINTER
)
7918 isneg
= aux
->alu_state
& BPF_ALU_NEG_VALUE
;
7919 issrc
= (aux
->alu_state
& BPF_ALU_SANITIZE
) ==
7920 BPF_ALU_SANITIZE_SRC
;
7922 off_reg
= issrc
? insn
->src_reg
: insn
->dst_reg
;
7924 *patch
++ = BPF_ALU64_IMM(BPF_MUL
, off_reg
, -1);
7925 *patch
++ = BPF_MOV32_IMM(BPF_REG_AX
, aux
->alu_limit
- 1);
7926 *patch
++ = BPF_ALU64_REG(BPF_SUB
, BPF_REG_AX
, off_reg
);
7927 *patch
++ = BPF_ALU64_REG(BPF_OR
, BPF_REG_AX
, off_reg
);
7928 *patch
++ = BPF_ALU64_IMM(BPF_NEG
, BPF_REG_AX
, 0);
7929 *patch
++ = BPF_ALU64_IMM(BPF_ARSH
, BPF_REG_AX
, 63);
7931 *patch
++ = BPF_ALU64_REG(BPF_AND
, BPF_REG_AX
,
7933 insn
->src_reg
= BPF_REG_AX
;
7935 *patch
++ = BPF_ALU64_REG(BPF_AND
, off_reg
,
7939 insn
->code
= insn
->code
== code_add
?
7940 code_sub
: code_add
;
7943 *patch
++ = BPF_ALU64_IMM(BPF_MUL
, off_reg
, -1);
7944 cnt
= patch
- insn_buf
;
7946 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
7951 env
->prog
= prog
= new_prog
;
7952 insn
= new_prog
->insnsi
+ i
+ delta
;
7956 if (insn
->code
!= (BPF_JMP
| BPF_CALL
))
7958 if (insn
->src_reg
== BPF_PSEUDO_CALL
)
7961 if (insn
->imm
== BPF_FUNC_get_route_realm
)
7962 prog
->dst_needed
= 1;
7963 if (insn
->imm
== BPF_FUNC_get_prandom_u32
)
7964 bpf_user_rnd_init_once();
7965 if (insn
->imm
== BPF_FUNC_override_return
)
7966 prog
->kprobe_override
= 1;
7967 if (insn
->imm
== BPF_FUNC_tail_call
) {
7968 /* If we tail call into other programs, we
7969 * cannot make any assumptions since they can
7970 * be replaced dynamically during runtime in
7971 * the program array.
7973 prog
->cb_access
= 1;
7974 env
->prog
->aux
->stack_depth
= MAX_BPF_STACK
;
7975 env
->prog
->aux
->max_pkt_offset
= MAX_PACKET_OFF
;
7977 /* mark bpf_tail_call as different opcode to avoid
7978 * conditional branch in the interpeter for every normal
7979 * call and to prevent accidental JITing by JIT compiler
7980 * that doesn't support bpf_tail_call yet
7983 insn
->code
= BPF_JMP
| BPF_TAIL_CALL
;
7985 aux
= &env
->insn_aux_data
[i
+ delta
];
7986 if (!bpf_map_ptr_unpriv(aux
))
7989 /* instead of changing every JIT dealing with tail_call
7990 * emit two extra insns:
7991 * if (index >= max_entries) goto out;
7992 * index &= array->index_mask;
7993 * to avoid out-of-bounds cpu speculation
7995 if (bpf_map_ptr_poisoned(aux
)) {
7996 verbose(env
, "tail_call abusing map_ptr\n");
8000 map_ptr
= BPF_MAP_PTR(aux
->map_state
);
8001 insn_buf
[0] = BPF_JMP_IMM(BPF_JGE
, BPF_REG_3
,
8002 map_ptr
->max_entries
, 2);
8003 insn_buf
[1] = BPF_ALU32_IMM(BPF_AND
, BPF_REG_3
,
8004 container_of(map_ptr
,
8007 insn_buf
[2] = *insn
;
8009 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
8014 env
->prog
= prog
= new_prog
;
8015 insn
= new_prog
->insnsi
+ i
+ delta
;
8019 /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
8020 * and other inlining handlers are currently limited to 64 bit
8023 if (prog
->jit_requested
&& BITS_PER_LONG
== 64 &&
8024 (insn
->imm
== BPF_FUNC_map_lookup_elem
||
8025 insn
->imm
== BPF_FUNC_map_update_elem
||
8026 insn
->imm
== BPF_FUNC_map_delete_elem
||
8027 insn
->imm
== BPF_FUNC_map_push_elem
||
8028 insn
->imm
== BPF_FUNC_map_pop_elem
||
8029 insn
->imm
== BPF_FUNC_map_peek_elem
)) {
8030 aux
= &env
->insn_aux_data
[i
+ delta
];
8031 if (bpf_map_ptr_poisoned(aux
))
8032 goto patch_call_imm
;
8034 map_ptr
= BPF_MAP_PTR(aux
->map_state
);
8036 if (insn
->imm
== BPF_FUNC_map_lookup_elem
&&
8037 ops
->map_gen_lookup
) {
8038 cnt
= ops
->map_gen_lookup(map_ptr
, insn_buf
);
8039 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
)) {
8040 verbose(env
, "bpf verifier is misconfigured\n");
8044 new_prog
= bpf_patch_insn_data(env
, i
+ delta
,
8050 env
->prog
= prog
= new_prog
;
8051 insn
= new_prog
->insnsi
+ i
+ delta
;
8055 BUILD_BUG_ON(!__same_type(ops
->map_lookup_elem
,
8056 (void *(*)(struct bpf_map
*map
, void *key
))NULL
));
8057 BUILD_BUG_ON(!__same_type(ops
->map_delete_elem
,
8058 (int (*)(struct bpf_map
*map
, void *key
))NULL
));
8059 BUILD_BUG_ON(!__same_type(ops
->map_update_elem
,
8060 (int (*)(struct bpf_map
*map
, void *key
, void *value
,
8062 BUILD_BUG_ON(!__same_type(ops
->map_push_elem
,
8063 (int (*)(struct bpf_map
*map
, void *value
,
8065 BUILD_BUG_ON(!__same_type(ops
->map_pop_elem
,
8066 (int (*)(struct bpf_map
*map
, void *value
))NULL
));
8067 BUILD_BUG_ON(!__same_type(ops
->map_peek_elem
,
8068 (int (*)(struct bpf_map
*map
, void *value
))NULL
));
8070 switch (insn
->imm
) {
8071 case BPF_FUNC_map_lookup_elem
:
8072 insn
->imm
= BPF_CAST_CALL(ops
->map_lookup_elem
) -
8075 case BPF_FUNC_map_update_elem
:
8076 insn
->imm
= BPF_CAST_CALL(ops
->map_update_elem
) -
8079 case BPF_FUNC_map_delete_elem
:
8080 insn
->imm
= BPF_CAST_CALL(ops
->map_delete_elem
) -
8083 case BPF_FUNC_map_push_elem
:
8084 insn
->imm
= BPF_CAST_CALL(ops
->map_push_elem
) -
8087 case BPF_FUNC_map_pop_elem
:
8088 insn
->imm
= BPF_CAST_CALL(ops
->map_pop_elem
) -
8091 case BPF_FUNC_map_peek_elem
:
8092 insn
->imm
= BPF_CAST_CALL(ops
->map_peek_elem
) -
8097 goto patch_call_imm
;
8101 fn
= env
->ops
->get_func_proto(insn
->imm
, env
->prog
);
8102 /* all functions that have prototype and verifier allowed
8103 * programs to call them, must be real in-kernel functions
8107 "kernel subsystem misconfigured func %s#%d\n",
8108 func_id_name(insn
->imm
), insn
->imm
);
8111 insn
->imm
= fn
->func
- __bpf_call_base
;
8117 static void free_states(struct bpf_verifier_env
*env
)
8119 struct bpf_verifier_state_list
*sl
, *sln
;
8122 sl
= env
->free_list
;
8125 free_verifier_state(&sl
->state
, false);
8130 if (!env
->explored_states
)
8133 for (i
= 0; i
< env
->prog
->len
; i
++) {
8134 sl
= env
->explored_states
[i
];
8137 while (sl
!= STATE_LIST_MARK
) {
8139 free_verifier_state(&sl
->state
, false);
8145 kvfree(env
->explored_states
);
8148 static void print_verification_stats(struct bpf_verifier_env
*env
)
8152 if (env
->log
.level
& BPF_LOG_STATS
) {
8153 verbose(env
, "verification time %lld usec\n",
8154 div_u64(env
->verification_time
, 1000));
8155 verbose(env
, "stack depth ");
8156 for (i
= 0; i
< env
->subprog_cnt
; i
++) {
8157 u32 depth
= env
->subprog_info
[i
].stack_depth
;
8159 verbose(env
, "%d", depth
);
8160 if (i
+ 1 < env
->subprog_cnt
)
8165 verbose(env
, "processed %d insns (limit %d) max_states_per_insn %d "
8166 "total_states %d peak_states %d mark_read %d\n",
8167 env
->insn_processed
, BPF_COMPLEXITY_LIMIT_INSNS
,
8168 env
->max_states_per_insn
, env
->total_states
,
8169 env
->peak_states
, env
->longest_mark_read_walk
);
8172 int bpf_check(struct bpf_prog
**prog
, union bpf_attr
*attr
,
8173 union bpf_attr __user
*uattr
)
8175 u64 start_time
= ktime_get_ns();
8176 struct bpf_verifier_env
*env
;
8177 struct bpf_verifier_log
*log
;
8178 int i
, len
, ret
= -EINVAL
;
8181 /* no program is valid */
8182 if (ARRAY_SIZE(bpf_verifier_ops
) == 0)
8185 /* 'struct bpf_verifier_env' can be global, but since it's not small,
8186 * allocate/free it every time bpf_check() is called
8188 env
= kzalloc(sizeof(struct bpf_verifier_env
), GFP_KERNEL
);
8194 env
->insn_aux_data
=
8195 vzalloc(array_size(sizeof(struct bpf_insn_aux_data
), len
));
8197 if (!env
->insn_aux_data
)
8199 for (i
= 0; i
< len
; i
++)
8200 env
->insn_aux_data
[i
].orig_idx
= i
;
8202 env
->ops
= bpf_verifier_ops
[env
->prog
->type
];
8203 is_priv
= capable(CAP_SYS_ADMIN
);
8205 /* grab the mutex to protect few globals used by verifier */
8207 mutex_lock(&bpf_verifier_lock
);
8209 if (attr
->log_level
|| attr
->log_buf
|| attr
->log_size
) {
8210 /* user requested verbose verifier output
8211 * and supplied buffer to store the verification trace
8213 log
->level
= attr
->log_level
;
8214 log
->ubuf
= (char __user
*) (unsigned long) attr
->log_buf
;
8215 log
->len_total
= attr
->log_size
;
8218 /* log attributes have to be sane */
8219 if (log
->len_total
< 128 || log
->len_total
> UINT_MAX
>> 2 ||
8220 !log
->level
|| !log
->ubuf
|| log
->level
& ~BPF_LOG_MASK
)
8224 env
->strict_alignment
= !!(attr
->prog_flags
& BPF_F_STRICT_ALIGNMENT
);
8225 if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
))
8226 env
->strict_alignment
= true;
8227 if (attr
->prog_flags
& BPF_F_ANY_ALIGNMENT
)
8228 env
->strict_alignment
= false;
8230 env
->allow_ptr_leaks
= is_priv
;
8232 ret
= replace_map_fd_with_map_ptr(env
);
8234 goto skip_full_check
;
8236 if (bpf_prog_is_dev_bound(env
->prog
->aux
)) {
8237 ret
= bpf_prog_offload_verifier_prep(env
->prog
);
8239 goto skip_full_check
;
8242 env
->explored_states
= kvcalloc(env
->prog
->len
,
8243 sizeof(struct bpf_verifier_state_list
*),
8246 if (!env
->explored_states
)
8247 goto skip_full_check
;
8249 ret
= check_subprogs(env
);
8251 goto skip_full_check
;
8253 ret
= check_btf_info(env
, attr
, uattr
);
8255 goto skip_full_check
;
8257 ret
= check_cfg(env
);
8259 goto skip_full_check
;
8261 ret
= do_check(env
);
8262 if (env
->cur_state
) {
8263 free_verifier_state(env
->cur_state
, true);
8264 env
->cur_state
= NULL
;
8267 if (ret
== 0 && bpf_prog_is_dev_bound(env
->prog
->aux
))
8268 ret
= bpf_prog_offload_finalize(env
);
8271 while (!pop_stack(env
, NULL
, NULL
));
8275 ret
= check_max_stack_depth(env
);
8277 /* instruction rewrites happen after this point */
8280 opt_hard_wire_dead_code_branches(env
);
8282 ret
= opt_remove_dead_code(env
);
8284 ret
= opt_remove_nops(env
);
8287 sanitize_dead_code(env
);
8291 /* program is valid, convert *(u32*)(ctx + off) accesses */
8292 ret
= convert_ctx_accesses(env
);
8295 ret
= fixup_bpf_calls(env
);
8298 ret
= fixup_call_args(env
);
8300 env
->verification_time
= ktime_get_ns() - start_time
;
8301 print_verification_stats(env
);
8303 if (log
->level
&& bpf_verifier_log_full(log
))
8305 if (log
->level
&& !log
->ubuf
) {
8307 goto err_release_maps
;
8310 if (ret
== 0 && env
->used_map_cnt
) {
8311 /* if program passed verifier, update used_maps in bpf_prog_info */
8312 env
->prog
->aux
->used_maps
= kmalloc_array(env
->used_map_cnt
,
8313 sizeof(env
->used_maps
[0]),
8316 if (!env
->prog
->aux
->used_maps
) {
8318 goto err_release_maps
;
8321 memcpy(env
->prog
->aux
->used_maps
, env
->used_maps
,
8322 sizeof(env
->used_maps
[0]) * env
->used_map_cnt
);
8323 env
->prog
->aux
->used_map_cnt
= env
->used_map_cnt
;
8325 /* program is valid. Convert pseudo bpf_ld_imm64 into generic
8326 * bpf_ld_imm64 instructions
8328 convert_pseudo_ld_imm64(env
);
8332 adjust_btf_func(env
);
8335 if (!env
->prog
->aux
->used_maps
)
8336 /* if we didn't copy map pointers into bpf_prog_info, release
8337 * them now. Otherwise free_used_maps() will release them.
8343 mutex_unlock(&bpf_verifier_lock
);
8344 vfree(env
->insn_aux_data
);