1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
2 * Copyright (c) 2016 Facebook
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 #include <linux/kernel.h>
14 #include <linux/types.h>
15 #include <linux/slab.h>
16 #include <linux/bpf.h>
17 #include <linux/bpf_verifier.h>
18 #include <linux/filter.h>
19 #include <net/netlink.h>
20 #include <linux/file.h>
21 #include <linux/vmalloc.h>
22 #include <linux/stringify.h>
24 /* bpf_check() is a static code analyzer that walks eBPF program
25 * instruction by instruction and updates register/stack state.
26 * All paths of conditional branches are analyzed until 'bpf_exit' insn.
28 * The first pass is depth-first-search to check that the program is a DAG.
29 * It rejects the following programs:
30 * - larger than BPF_MAXINSNS insns
31 * - if loop is present (detected via back-edge)
32 * - unreachable insns exist (shouldn't be a forest. program = one function)
33 * - out of bounds or malformed jumps
34 * The second pass is all possible path descent from the 1st insn.
35 * Since it's analyzing all pathes through the program, the length of the
36 * analysis is limited to 64k insn, which may be hit even if total number of
37 * insn is less then 4K, but there are too many branches that change stack/regs.
38 * Number of 'branches to be analyzed' is limited to 1k
40 * On entry to each instruction, each register has a type, and the instruction
41 * changes the types of the registers depending on instruction semantics.
42 * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
45 * All registers are 64-bit.
46 * R0 - return register
47 * R1-R5 argument passing registers
48 * R6-R9 callee saved registers
49 * R10 - frame pointer read-only
51 * At the start of BPF program the register R1 contains a pointer to bpf_context
52 * and has type PTR_TO_CTX.
54 * Verifier tracks arithmetic operations on pointers in case:
55 * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
56 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
57 * 1st insn copies R10 (which has FRAME_PTR) type into R1
58 * and 2nd arithmetic instruction is pattern matched to recognize
59 * that it wants to construct a pointer to some element within stack.
60 * So after 2nd insn, the register R1 has type PTR_TO_STACK
61 * (and -20 constant is saved for further stack bounds checking).
62 * Meaning that this reg is a pointer to stack plus known immediate constant.
64 * Most of the time the registers have UNKNOWN_VALUE type, which
65 * means the register has some value, but it's not a valid pointer.
66 * (like pointer plus pointer becomes UNKNOWN_VALUE type)
68 * When verifier sees load or store instructions the type of base register
69 * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, FRAME_PTR. These are three pointer
70 * types recognized by check_mem_access() function.
72 * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
73 * and the range of [ptr, ptr + map's value_size) is accessible.
75 * registers used to pass values to function calls are checked against
76 * function argument constraints.
78 * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
79 * It means that the register type passed to this function must be
80 * PTR_TO_STACK and it will be used inside the function as
81 * 'pointer to map element key'
83 * For example the argument constraints for bpf_map_lookup_elem():
84 * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
85 * .arg1_type = ARG_CONST_MAP_PTR,
86 * .arg2_type = ARG_PTR_TO_MAP_KEY,
88 * ret_type says that this function returns 'pointer to map elem value or null'
89 * function expects 1st argument to be a const pointer to 'struct bpf_map' and
90 * 2nd argument should be a pointer to stack, which will be used inside
91 * the helper function as a pointer to map element key.
93 * On the kernel side the helper function looks like:
94 * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
96 * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
97 * void *key = (void *) (unsigned long) r2;
100 * here kernel can access 'key' and 'map' pointers safely, knowing that
101 * [key, key + map->key_size) bytes are valid and were initialized on
102 * the stack of eBPF program.
105 * Corresponding eBPF program may look like:
106 * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR
107 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
108 * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP
109 * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
110 * here verifier looks at prototype of map_lookup_elem() and sees:
111 * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
112 * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
114 * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
115 * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
116 * and were initialized prior to this call.
117 * If it's ok, then verifier allows this BPF_CALL insn and looks at
118 * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
119 * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
120 * returns ether pointer to map value or NULL.
122 * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
123 * insn, the register holding that pointer in the true branch changes state to
124 * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
125 * branch. See check_cond_jmp_op().
127 * After the call R0 is set to return type of the function and registers R1-R5
128 * are set to NOT_INIT to indicate that they are no longer readable.
131 /* verifier_state + insn_idx are pushed to stack when branch is encountered */
132 struct bpf_verifier_stack_elem
{
133 /* verifer state is 'st'
134 * before processing instruction 'insn_idx'
135 * and after processing instruction 'prev_insn_idx'
137 struct bpf_verifier_state st
;
140 struct bpf_verifier_stack_elem
*next
;
143 #define BPF_COMPLEXITY_LIMIT_INSNS 65536
144 #define BPF_COMPLEXITY_LIMIT_STACK 1024
146 #define BPF_MAP_PTR_POISON ((void *)0xeB9F + POISON_POINTER_DELTA)
148 struct bpf_call_arg_meta
{
149 struct bpf_map
*map_ptr
;
156 /* verbose verifier prints what it's seeing
157 * bpf_check() is called under lock, so no race to access these global vars
159 static u32 log_level
, log_size
, log_len
;
160 static char *log_buf
;
162 static DEFINE_MUTEX(bpf_verifier_lock
);
164 /* log_level controls verbosity level of eBPF verifier.
165 * verbose() is used to dump the verification trace to the log, so the user
166 * can figure out what's wrong with the program
168 static __printf(1, 2) void verbose(const char *fmt
, ...)
172 if (log_level
== 0 || log_len
>= log_size
- 1)
176 log_len
+= vscnprintf(log_buf
+ log_len
, log_size
- log_len
, fmt
, args
);
180 /* string representation of 'enum bpf_reg_type' */
181 static const char * const reg_type_str
[] = {
183 [UNKNOWN_VALUE
] = "inv",
184 [PTR_TO_CTX
] = "ctx",
185 [CONST_PTR_TO_MAP
] = "map_ptr",
186 [PTR_TO_MAP_VALUE
] = "map_value",
187 [PTR_TO_MAP_VALUE_OR_NULL
] = "map_value_or_null",
188 [PTR_TO_MAP_VALUE_ADJ
] = "map_value_adj",
190 [PTR_TO_STACK
] = "fp",
192 [PTR_TO_PACKET
] = "pkt",
193 [PTR_TO_PACKET_END
] = "pkt_end",
196 #define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
197 static const char * const func_id_str
[] = {
198 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN
)
200 #undef __BPF_FUNC_STR_FN
202 static const char *func_id_name(int id
)
204 BUILD_BUG_ON(ARRAY_SIZE(func_id_str
) != __BPF_FUNC_MAX_ID
);
206 if (id
>= 0 && id
< __BPF_FUNC_MAX_ID
&& func_id_str
[id
])
207 return func_id_str
[id
];
212 static void print_verifier_state(struct bpf_verifier_state
*state
)
214 struct bpf_reg_state
*reg
;
218 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
219 reg
= &state
->regs
[i
];
223 verbose(" R%d=%s", i
, reg_type_str
[t
]);
224 if (t
== CONST_IMM
|| t
== PTR_TO_STACK
)
225 verbose("%lld", reg
->imm
);
226 else if (t
== PTR_TO_PACKET
)
227 verbose("(id=%d,off=%d,r=%d)",
228 reg
->id
, reg
->off
, reg
->range
);
229 else if (t
== UNKNOWN_VALUE
&& reg
->imm
)
230 verbose("%lld", reg
->imm
);
231 else if (t
== CONST_PTR_TO_MAP
|| t
== PTR_TO_MAP_VALUE
||
232 t
== PTR_TO_MAP_VALUE_OR_NULL
||
233 t
== PTR_TO_MAP_VALUE_ADJ
)
234 verbose("(ks=%d,vs=%d,id=%u)",
235 reg
->map_ptr
->key_size
,
236 reg
->map_ptr
->value_size
,
238 if (reg
->min_value
!= BPF_REGISTER_MIN_RANGE
)
239 verbose(",min_value=%lld",
240 (long long)reg
->min_value
);
241 if (reg
->max_value
!= BPF_REGISTER_MAX_RANGE
)
242 verbose(",max_value=%llu",
243 (unsigned long long)reg
->max_value
);
245 for (i
= 0; i
< MAX_BPF_STACK
; i
+= BPF_REG_SIZE
) {
246 if (state
->stack_slot_type
[i
] == STACK_SPILL
)
247 verbose(" fp%d=%s", -MAX_BPF_STACK
+ i
,
248 reg_type_str
[state
->spilled_regs
[i
/ BPF_REG_SIZE
].type
]);
253 static const char *const bpf_class_string
[] = {
261 [BPF_ALU64
] = "alu64",
264 static const char *const bpf_alu_string
[16] = {
265 [BPF_ADD
>> 4] = "+=",
266 [BPF_SUB
>> 4] = "-=",
267 [BPF_MUL
>> 4] = "*=",
268 [BPF_DIV
>> 4] = "/=",
269 [BPF_OR
>> 4] = "|=",
270 [BPF_AND
>> 4] = "&=",
271 [BPF_LSH
>> 4] = "<<=",
272 [BPF_RSH
>> 4] = ">>=",
273 [BPF_NEG
>> 4] = "neg",
274 [BPF_MOD
>> 4] = "%=",
275 [BPF_XOR
>> 4] = "^=",
276 [BPF_MOV
>> 4] = "=",
277 [BPF_ARSH
>> 4] = "s>>=",
278 [BPF_END
>> 4] = "endian",
281 static const char *const bpf_ldst_string
[] = {
282 [BPF_W
>> 3] = "u32",
283 [BPF_H
>> 3] = "u16",
285 [BPF_DW
>> 3] = "u64",
288 static const char *const bpf_jmp_string
[16] = {
289 [BPF_JA
>> 4] = "jmp",
290 [BPF_JEQ
>> 4] = "==",
291 [BPF_JGT
>> 4] = ">",
292 [BPF_JGE
>> 4] = ">=",
293 [BPF_JSET
>> 4] = "&",
294 [BPF_JNE
>> 4] = "!=",
295 [BPF_JSGT
>> 4] = "s>",
296 [BPF_JSGE
>> 4] = "s>=",
297 [BPF_CALL
>> 4] = "call",
298 [BPF_EXIT
>> 4] = "exit",
301 static void print_bpf_insn(struct bpf_insn
*insn
)
303 u8
class = BPF_CLASS(insn
->code
);
305 if (class == BPF_ALU
|| class == BPF_ALU64
) {
306 if (BPF_SRC(insn
->code
) == BPF_X
)
307 verbose("(%02x) %sr%d %s %sr%d\n",
308 insn
->code
, class == BPF_ALU
? "(u32) " : "",
310 bpf_alu_string
[BPF_OP(insn
->code
) >> 4],
311 class == BPF_ALU
? "(u32) " : "",
314 verbose("(%02x) %sr%d %s %s%d\n",
315 insn
->code
, class == BPF_ALU
? "(u32) " : "",
317 bpf_alu_string
[BPF_OP(insn
->code
) >> 4],
318 class == BPF_ALU
? "(u32) " : "",
320 } else if (class == BPF_STX
) {
321 if (BPF_MODE(insn
->code
) == BPF_MEM
)
322 verbose("(%02x) *(%s *)(r%d %+d) = r%d\n",
324 bpf_ldst_string
[BPF_SIZE(insn
->code
) >> 3],
326 insn
->off
, insn
->src_reg
);
327 else if (BPF_MODE(insn
->code
) == BPF_XADD
)
328 verbose("(%02x) lock *(%s *)(r%d %+d) += r%d\n",
330 bpf_ldst_string
[BPF_SIZE(insn
->code
) >> 3],
331 insn
->dst_reg
, insn
->off
,
334 verbose("BUG_%02x\n", insn
->code
);
335 } else if (class == BPF_ST
) {
336 if (BPF_MODE(insn
->code
) != BPF_MEM
) {
337 verbose("BUG_st_%02x\n", insn
->code
);
340 verbose("(%02x) *(%s *)(r%d %+d) = %d\n",
342 bpf_ldst_string
[BPF_SIZE(insn
->code
) >> 3],
344 insn
->off
, insn
->imm
);
345 } else if (class == BPF_LDX
) {
346 if (BPF_MODE(insn
->code
) != BPF_MEM
) {
347 verbose("BUG_ldx_%02x\n", insn
->code
);
350 verbose("(%02x) r%d = *(%s *)(r%d %+d)\n",
351 insn
->code
, insn
->dst_reg
,
352 bpf_ldst_string
[BPF_SIZE(insn
->code
) >> 3],
353 insn
->src_reg
, insn
->off
);
354 } else if (class == BPF_LD
) {
355 if (BPF_MODE(insn
->code
) == BPF_ABS
) {
356 verbose("(%02x) r0 = *(%s *)skb[%d]\n",
358 bpf_ldst_string
[BPF_SIZE(insn
->code
) >> 3],
360 } else if (BPF_MODE(insn
->code
) == BPF_IND
) {
361 verbose("(%02x) r0 = *(%s *)skb[r%d + %d]\n",
363 bpf_ldst_string
[BPF_SIZE(insn
->code
) >> 3],
364 insn
->src_reg
, insn
->imm
);
365 } else if (BPF_MODE(insn
->code
) == BPF_IMM
) {
366 verbose("(%02x) r%d = 0x%x\n",
367 insn
->code
, insn
->dst_reg
, insn
->imm
);
369 verbose("BUG_ld_%02x\n", insn
->code
);
372 } else if (class == BPF_JMP
) {
373 u8 opcode
= BPF_OP(insn
->code
);
375 if (opcode
== BPF_CALL
) {
376 verbose("(%02x) call %s#%d\n", insn
->code
,
377 func_id_name(insn
->imm
), insn
->imm
);
378 } else if (insn
->code
== (BPF_JMP
| BPF_JA
)) {
379 verbose("(%02x) goto pc%+d\n",
380 insn
->code
, insn
->off
);
381 } else if (insn
->code
== (BPF_JMP
| BPF_EXIT
)) {
382 verbose("(%02x) exit\n", insn
->code
);
383 } else if (BPF_SRC(insn
->code
) == BPF_X
) {
384 verbose("(%02x) if r%d %s r%d goto pc%+d\n",
385 insn
->code
, insn
->dst_reg
,
386 bpf_jmp_string
[BPF_OP(insn
->code
) >> 4],
387 insn
->src_reg
, insn
->off
);
389 verbose("(%02x) if r%d %s 0x%x goto pc%+d\n",
390 insn
->code
, insn
->dst_reg
,
391 bpf_jmp_string
[BPF_OP(insn
->code
) >> 4],
392 insn
->imm
, insn
->off
);
395 verbose("(%02x) %s\n", insn
->code
, bpf_class_string
[class]);
399 static int pop_stack(struct bpf_verifier_env
*env
, int *prev_insn_idx
)
401 struct bpf_verifier_stack_elem
*elem
;
404 if (env
->head
== NULL
)
407 memcpy(&env
->cur_state
, &env
->head
->st
, sizeof(env
->cur_state
));
408 insn_idx
= env
->head
->insn_idx
;
410 *prev_insn_idx
= env
->head
->prev_insn_idx
;
411 elem
= env
->head
->next
;
418 static struct bpf_verifier_state
*push_stack(struct bpf_verifier_env
*env
,
419 int insn_idx
, int prev_insn_idx
)
421 struct bpf_verifier_stack_elem
*elem
;
423 elem
= kmalloc(sizeof(struct bpf_verifier_stack_elem
), GFP_KERNEL
);
427 memcpy(&elem
->st
, &env
->cur_state
, sizeof(env
->cur_state
));
428 elem
->insn_idx
= insn_idx
;
429 elem
->prev_insn_idx
= prev_insn_idx
;
430 elem
->next
= env
->head
;
433 if (env
->stack_size
> BPF_COMPLEXITY_LIMIT_STACK
) {
434 verbose("BPF program is too complex\n");
439 /* pop all elements and return */
440 while (pop_stack(env
, NULL
) >= 0);
444 #define CALLER_SAVED_REGS 6
445 static const int caller_saved
[CALLER_SAVED_REGS
] = {
446 BPF_REG_0
, BPF_REG_1
, BPF_REG_2
, BPF_REG_3
, BPF_REG_4
, BPF_REG_5
449 static void init_reg_state(struct bpf_reg_state
*regs
)
453 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
454 regs
[i
].type
= NOT_INIT
;
456 regs
[i
].min_value
= BPF_REGISTER_MIN_RANGE
;
457 regs
[i
].max_value
= BPF_REGISTER_MAX_RANGE
;
461 regs
[BPF_REG_FP
].type
= FRAME_PTR
;
463 /* 1st arg to a function */
464 regs
[BPF_REG_1
].type
= PTR_TO_CTX
;
467 static void __mark_reg_unknown_value(struct bpf_reg_state
*regs
, u32 regno
)
469 regs
[regno
].type
= UNKNOWN_VALUE
;
474 static void mark_reg_unknown_value(struct bpf_reg_state
*regs
, u32 regno
)
476 BUG_ON(regno
>= MAX_BPF_REG
);
477 __mark_reg_unknown_value(regs
, regno
);
480 static void reset_reg_range_values(struct bpf_reg_state
*regs
, u32 regno
)
482 regs
[regno
].min_value
= BPF_REGISTER_MIN_RANGE
;
483 regs
[regno
].max_value
= BPF_REGISTER_MAX_RANGE
;
486 static void mark_reg_unknown_value_and_range(struct bpf_reg_state
*regs
,
489 mark_reg_unknown_value(regs
, regno
);
490 reset_reg_range_values(regs
, regno
);
494 SRC_OP
, /* register is used as source operand */
495 DST_OP
, /* register is used as destination operand */
496 DST_OP_NO_MARK
/* same as above, check only, don't mark */
499 static int check_reg_arg(struct bpf_reg_state
*regs
, u32 regno
,
502 if (regno
>= MAX_BPF_REG
) {
503 verbose("R%d is invalid\n", regno
);
508 /* check whether register used as source operand can be read */
509 if (regs
[regno
].type
== NOT_INIT
) {
510 verbose("R%d !read_ok\n", regno
);
514 /* check whether register used as dest operand can be written to */
515 if (regno
== BPF_REG_FP
) {
516 verbose("frame pointer is read only\n");
520 mark_reg_unknown_value(regs
, regno
);
525 static int bpf_size_to_bytes(int bpf_size
)
527 if (bpf_size
== BPF_W
)
529 else if (bpf_size
== BPF_H
)
531 else if (bpf_size
== BPF_B
)
533 else if (bpf_size
== BPF_DW
)
539 static bool is_spillable_regtype(enum bpf_reg_type type
)
542 case PTR_TO_MAP_VALUE
:
543 case PTR_TO_MAP_VALUE_OR_NULL
:
544 case PTR_TO_MAP_VALUE_ADJ
:
548 case PTR_TO_PACKET_END
:
550 case CONST_PTR_TO_MAP
:
557 /* check_stack_read/write functions track spill/fill of registers,
558 * stack boundary and alignment are checked in check_mem_access()
560 static int check_stack_write(struct bpf_verifier_state
*state
, int off
,
561 int size
, int value_regno
)
564 /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
565 * so it's aligned access and [off, off + size) are within stack limits
568 if (value_regno
>= 0 &&
569 is_spillable_regtype(state
->regs
[value_regno
].type
)) {
571 /* register containing pointer is being spilled into stack */
572 if (size
!= BPF_REG_SIZE
) {
573 verbose("invalid size of register spill\n");
577 /* save register state */
578 state
->spilled_regs
[(MAX_BPF_STACK
+ off
) / BPF_REG_SIZE
] =
579 state
->regs
[value_regno
];
581 for (i
= 0; i
< BPF_REG_SIZE
; i
++)
582 state
->stack_slot_type
[MAX_BPF_STACK
+ off
+ i
] = STACK_SPILL
;
584 /* regular write of data into stack */
585 state
->spilled_regs
[(MAX_BPF_STACK
+ off
) / BPF_REG_SIZE
] =
586 (struct bpf_reg_state
) {};
588 for (i
= 0; i
< size
; i
++)
589 state
->stack_slot_type
[MAX_BPF_STACK
+ off
+ i
] = STACK_MISC
;
594 static int check_stack_read(struct bpf_verifier_state
*state
, int off
, int size
,
600 slot_type
= &state
->stack_slot_type
[MAX_BPF_STACK
+ off
];
602 if (slot_type
[0] == STACK_SPILL
) {
603 if (size
!= BPF_REG_SIZE
) {
604 verbose("invalid size of register spill\n");
607 for (i
= 1; i
< BPF_REG_SIZE
; i
++) {
608 if (slot_type
[i
] != STACK_SPILL
) {
609 verbose("corrupted spill memory\n");
614 if (value_regno
>= 0)
615 /* restore register state from stack */
616 state
->regs
[value_regno
] =
617 state
->spilled_regs
[(MAX_BPF_STACK
+ off
) / BPF_REG_SIZE
];
620 for (i
= 0; i
< size
; i
++) {
621 if (slot_type
[i
] != STACK_MISC
) {
622 verbose("invalid read from stack off %d+%d size %d\n",
627 if (value_regno
>= 0)
628 /* have read misc data from the stack */
629 mark_reg_unknown_value_and_range(state
->regs
,
635 /* check read/write into map element returned by bpf_map_lookup_elem() */
636 static int check_map_access(struct bpf_verifier_env
*env
, u32 regno
, int off
,
639 struct bpf_map
*map
= env
->cur_state
.regs
[regno
].map_ptr
;
641 if (off
< 0 || size
<= 0 || off
+ size
> map
->value_size
) {
642 verbose("invalid access to map value, value_size=%d off=%d size=%d\n",
643 map
->value_size
, off
, size
);
649 /* check read/write into an adjusted map element */
650 static int check_map_access_adj(struct bpf_verifier_env
*env
, u32 regno
,
653 struct bpf_verifier_state
*state
= &env
->cur_state
;
654 struct bpf_reg_state
*reg
= &state
->regs
[regno
];
657 /* We adjusted the register to this map value, so we
658 * need to change off and size to min_value and max_value
659 * respectively to make sure our theoretical access will be
663 print_verifier_state(state
);
664 env
->varlen_map_value_access
= true;
665 /* The minimum value is only important with signed
666 * comparisons where we can't assume the floor of a
667 * value is 0. If we are using signed variables for our
668 * index'es we need to make sure that whatever we use
669 * will have a set floor within our range.
671 if (reg
->min_value
< 0) {
672 verbose("R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
676 err
= check_map_access(env
, regno
, reg
->min_value
+ off
, size
);
678 verbose("R%d min value is outside of the array range\n",
683 /* If we haven't set a max value then we need to bail
684 * since we can't be sure we won't do bad things.
686 if (reg
->max_value
== BPF_REGISTER_MAX_RANGE
) {
687 verbose("R%d unbounded memory access, make sure to bounds check any array access into a map\n",
691 return check_map_access(env
, regno
, reg
->max_value
+ off
, size
);
694 #define MAX_PACKET_OFF 0xffff
696 static bool may_access_direct_pkt_data(struct bpf_verifier_env
*env
,
697 const struct bpf_call_arg_meta
*meta
,
698 enum bpf_access_type t
)
700 switch (env
->prog
->type
) {
701 case BPF_PROG_TYPE_LWT_IN
:
702 case BPF_PROG_TYPE_LWT_OUT
:
703 /* dst_input() and dst_output() can't write for now */
707 case BPF_PROG_TYPE_SCHED_CLS
:
708 case BPF_PROG_TYPE_SCHED_ACT
:
709 case BPF_PROG_TYPE_XDP
:
710 case BPF_PROG_TYPE_LWT_XMIT
:
712 return meta
->pkt_access
;
714 env
->seen_direct_write
= true;
721 static int check_packet_access(struct bpf_verifier_env
*env
, u32 regno
, int off
,
724 struct bpf_reg_state
*regs
= env
->cur_state
.regs
;
725 struct bpf_reg_state
*reg
= ®s
[regno
];
728 if (off
< 0 || size
<= 0 || off
+ size
> reg
->range
) {
729 verbose("invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
730 off
, size
, regno
, reg
->id
, reg
->off
, reg
->range
);
736 /* check access to 'struct bpf_context' fields */
737 static int check_ctx_access(struct bpf_verifier_env
*env
, int off
, int size
,
738 enum bpf_access_type t
, enum bpf_reg_type
*reg_type
)
740 /* for analyzer ctx accesses are already validated and converted */
741 if (env
->analyzer_ops
)
744 if (env
->prog
->aux
->ops
->is_valid_access
&&
745 env
->prog
->aux
->ops
->is_valid_access(off
, size
, t
, reg_type
)) {
746 /* remember the offset of last byte accessed in ctx */
747 if (env
->prog
->aux
->max_ctx_offset
< off
+ size
)
748 env
->prog
->aux
->max_ctx_offset
= off
+ size
;
752 verbose("invalid bpf_context access off=%d size=%d\n", off
, size
);
756 static bool is_pointer_value(struct bpf_verifier_env
*env
, int regno
)
758 if (env
->allow_ptr_leaks
)
761 switch (env
->cur_state
.regs
[regno
].type
) {
770 static int check_pkt_ptr_alignment(const struct bpf_reg_state
*reg
,
773 if (reg
->id
&& size
!= 1) {
774 verbose("Unknown alignment. Only byte-sized access allowed in packet access.\n");
778 /* skb->data is NET_IP_ALIGN-ed */
779 if ((NET_IP_ALIGN
+ reg
->off
+ off
) % size
!= 0) {
780 verbose("misaligned packet access off %d+%d+%d size %d\n",
781 NET_IP_ALIGN
, reg
->off
, off
, size
);
788 static int check_val_ptr_alignment(const struct bpf_reg_state
*reg
,
792 verbose("Unknown alignment. Only byte-sized access allowed in value access.\n");
799 static int check_ptr_alignment(const struct bpf_reg_state
*reg
,
804 return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
) ? 0 :
805 check_pkt_ptr_alignment(reg
, off
, size
);
806 case PTR_TO_MAP_VALUE_ADJ
:
807 return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
) ? 0 :
808 check_val_ptr_alignment(reg
, size
);
810 if (off
% size
!= 0) {
811 verbose("misaligned access off %d size %d\n",
820 /* check whether memory at (regno + off) is accessible for t = (read | write)
821 * if t==write, value_regno is a register which value is stored into memory
822 * if t==read, value_regno is a register which will receive the value from memory
823 * if t==write && value_regno==-1, some unknown value is stored into memory
824 * if t==read && value_regno==-1, don't care what we read from memory
826 static int check_mem_access(struct bpf_verifier_env
*env
, u32 regno
, int off
,
827 int bpf_size
, enum bpf_access_type t
,
830 struct bpf_verifier_state
*state
= &env
->cur_state
;
831 struct bpf_reg_state
*reg
= &state
->regs
[regno
];
834 if (reg
->type
== PTR_TO_STACK
)
837 size
= bpf_size_to_bytes(bpf_size
);
841 err
= check_ptr_alignment(reg
, off
, size
);
845 if (reg
->type
== PTR_TO_MAP_VALUE
||
846 reg
->type
== PTR_TO_MAP_VALUE_ADJ
) {
847 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
848 is_pointer_value(env
, value_regno
)) {
849 verbose("R%d leaks addr into map\n", value_regno
);
853 if (reg
->type
== PTR_TO_MAP_VALUE_ADJ
)
854 err
= check_map_access_adj(env
, regno
, off
, size
);
856 err
= check_map_access(env
, regno
, off
, size
);
857 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
858 mark_reg_unknown_value_and_range(state
->regs
,
861 } else if (reg
->type
== PTR_TO_CTX
) {
862 enum bpf_reg_type reg_type
= UNKNOWN_VALUE
;
864 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
865 is_pointer_value(env
, value_regno
)) {
866 verbose("R%d leaks addr into ctx\n", value_regno
);
869 err
= check_ctx_access(env
, off
, size
, t
, ®_type
);
870 if (!err
&& t
== BPF_READ
&& value_regno
>= 0) {
871 mark_reg_unknown_value_and_range(state
->regs
,
873 /* note that reg.[id|off|range] == 0 */
874 state
->regs
[value_regno
].type
= reg_type
;
877 } else if (reg
->type
== FRAME_PTR
|| reg
->type
== PTR_TO_STACK
) {
878 if (off
>= 0 || off
< -MAX_BPF_STACK
) {
879 verbose("invalid stack off=%d size=%d\n", off
, size
);
882 if (t
== BPF_WRITE
) {
883 if (!env
->allow_ptr_leaks
&&
884 state
->stack_slot_type
[MAX_BPF_STACK
+ off
] == STACK_SPILL
&&
885 size
!= BPF_REG_SIZE
) {
886 verbose("attempt to corrupt spilled pointer on stack\n");
889 err
= check_stack_write(state
, off
, size
, value_regno
);
891 err
= check_stack_read(state
, off
, size
, value_regno
);
893 } else if (state
->regs
[regno
].type
== PTR_TO_PACKET
) {
894 if (t
== BPF_WRITE
&& !may_access_direct_pkt_data(env
, NULL
, t
)) {
895 verbose("cannot write into packet\n");
898 if (t
== BPF_WRITE
&& value_regno
>= 0 &&
899 is_pointer_value(env
, value_regno
)) {
900 verbose("R%d leaks addr into packet\n", value_regno
);
903 err
= check_packet_access(env
, regno
, off
, size
);
904 if (!err
&& t
== BPF_READ
&& value_regno
>= 0)
905 mark_reg_unknown_value_and_range(state
->regs
,
908 verbose("R%d invalid mem access '%s'\n",
909 regno
, reg_type_str
[reg
->type
]);
913 if (!err
&& size
<= 2 && value_regno
>= 0 && env
->allow_ptr_leaks
&&
914 state
->regs
[value_regno
].type
== UNKNOWN_VALUE
) {
915 /* 1 or 2 byte load zero-extends, determine the number of
916 * zero upper bits. Not doing it fo 4 byte load, since
917 * such values cannot be added to ptr_to_packet anyway.
919 state
->regs
[value_regno
].imm
= 64 - size
* 8;
924 static int check_xadd(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
926 struct bpf_reg_state
*regs
= env
->cur_state
.regs
;
929 if ((BPF_SIZE(insn
->code
) != BPF_W
&& BPF_SIZE(insn
->code
) != BPF_DW
) ||
931 verbose("BPF_XADD uses reserved fields\n");
935 /* check src1 operand */
936 err
= check_reg_arg(regs
, insn
->src_reg
, SRC_OP
);
940 /* check src2 operand */
941 err
= check_reg_arg(regs
, insn
->dst_reg
, SRC_OP
);
945 /* check whether atomic_add can read the memory */
946 err
= check_mem_access(env
, insn
->dst_reg
, insn
->off
,
947 BPF_SIZE(insn
->code
), BPF_READ
, -1);
951 /* check whether atomic_add can write into the same memory */
952 return check_mem_access(env
, insn
->dst_reg
, insn
->off
,
953 BPF_SIZE(insn
->code
), BPF_WRITE
, -1);
956 /* when register 'regno' is passed into function that will read 'access_size'
957 * bytes from that pointer, make sure that it's within stack boundary
958 * and all elements of stack are initialized
960 static int check_stack_boundary(struct bpf_verifier_env
*env
, int regno
,
961 int access_size
, bool zero_size_allowed
,
962 struct bpf_call_arg_meta
*meta
)
964 struct bpf_verifier_state
*state
= &env
->cur_state
;
965 struct bpf_reg_state
*regs
= state
->regs
;
968 if (regs
[regno
].type
!= PTR_TO_STACK
) {
969 if (zero_size_allowed
&& access_size
== 0 &&
970 regs
[regno
].type
== CONST_IMM
&&
971 regs
[regno
].imm
== 0)
974 verbose("R%d type=%s expected=%s\n", regno
,
975 reg_type_str
[regs
[regno
].type
],
976 reg_type_str
[PTR_TO_STACK
]);
980 off
= regs
[regno
].imm
;
981 if (off
>= 0 || off
< -MAX_BPF_STACK
|| off
+ access_size
> 0 ||
983 verbose("invalid stack type R%d off=%d access_size=%d\n",
984 regno
, off
, access_size
);
988 if (meta
&& meta
->raw_mode
) {
989 meta
->access_size
= access_size
;
994 for (i
= 0; i
< access_size
; i
++) {
995 if (state
->stack_slot_type
[MAX_BPF_STACK
+ off
+ i
] != STACK_MISC
) {
996 verbose("invalid indirect read from stack off %d+%d size %d\n",
997 off
, i
, access_size
);
1004 static int check_helper_mem_access(struct bpf_verifier_env
*env
, int regno
,
1005 int access_size
, bool zero_size_allowed
,
1006 struct bpf_call_arg_meta
*meta
)
1008 struct bpf_reg_state
*regs
= env
->cur_state
.regs
;
1010 switch (regs
[regno
].type
) {
1012 return check_packet_access(env
, regno
, 0, access_size
);
1013 case PTR_TO_MAP_VALUE
:
1014 return check_map_access(env
, regno
, 0, access_size
);
1015 case PTR_TO_MAP_VALUE_ADJ
:
1016 return check_map_access_adj(env
, regno
, 0, access_size
);
1017 default: /* const_imm|ptr_to_stack or invalid ptr */
1018 return check_stack_boundary(env
, regno
, access_size
,
1019 zero_size_allowed
, meta
);
1023 static int check_func_arg(struct bpf_verifier_env
*env
, u32 regno
,
1024 enum bpf_arg_type arg_type
,
1025 struct bpf_call_arg_meta
*meta
)
1027 struct bpf_reg_state
*regs
= env
->cur_state
.regs
, *reg
= ®s
[regno
];
1028 enum bpf_reg_type expected_type
, type
= reg
->type
;
1031 if (arg_type
== ARG_DONTCARE
)
1034 if (type
== NOT_INIT
) {
1035 verbose("R%d !read_ok\n", regno
);
1039 if (arg_type
== ARG_ANYTHING
) {
1040 if (is_pointer_value(env
, regno
)) {
1041 verbose("R%d leaks addr into helper function\n", regno
);
1047 if (type
== PTR_TO_PACKET
&&
1048 !may_access_direct_pkt_data(env
, meta
, BPF_READ
)) {
1049 verbose("helper access to the packet is not allowed\n");
1053 if (arg_type
== ARG_PTR_TO_MAP_KEY
||
1054 arg_type
== ARG_PTR_TO_MAP_VALUE
) {
1055 expected_type
= PTR_TO_STACK
;
1056 if (type
!= PTR_TO_PACKET
&& type
!= expected_type
)
1058 } else if (arg_type
== ARG_CONST_SIZE
||
1059 arg_type
== ARG_CONST_SIZE_OR_ZERO
) {
1060 expected_type
= CONST_IMM
;
1061 /* One exception. Allow UNKNOWN_VALUE registers when the
1062 * boundaries are known and don't cause unsafe memory accesses
1064 if (type
!= UNKNOWN_VALUE
&& type
!= expected_type
)
1066 } else if (arg_type
== ARG_CONST_MAP_PTR
) {
1067 expected_type
= CONST_PTR_TO_MAP
;
1068 if (type
!= expected_type
)
1070 } else if (arg_type
== ARG_PTR_TO_CTX
) {
1071 expected_type
= PTR_TO_CTX
;
1072 if (type
!= expected_type
)
1074 } else if (arg_type
== ARG_PTR_TO_MEM
||
1075 arg_type
== ARG_PTR_TO_UNINIT_MEM
) {
1076 expected_type
= PTR_TO_STACK
;
1077 /* One exception here. In case function allows for NULL to be
1078 * passed in as argument, it's a CONST_IMM type. Final test
1079 * happens during stack boundary checking.
1081 if (type
== CONST_IMM
&& reg
->imm
== 0)
1082 /* final test in check_stack_boundary() */;
1083 else if (type
!= PTR_TO_PACKET
&& type
!= PTR_TO_MAP_VALUE
&&
1084 type
!= PTR_TO_MAP_VALUE_ADJ
&& type
!= expected_type
)
1086 meta
->raw_mode
= arg_type
== ARG_PTR_TO_UNINIT_MEM
;
1088 verbose("unsupported arg_type %d\n", arg_type
);
1092 if (arg_type
== ARG_CONST_MAP_PTR
) {
1093 /* bpf_map_xxx(map_ptr) call: remember that map_ptr */
1094 meta
->map_ptr
= reg
->map_ptr
;
1095 } else if (arg_type
== ARG_PTR_TO_MAP_KEY
) {
1096 /* bpf_map_xxx(..., map_ptr, ..., key) call:
1097 * check that [key, key + map->key_size) are within
1098 * stack limits and initialized
1100 if (!meta
->map_ptr
) {
1101 /* in function declaration map_ptr must come before
1102 * map_key, so that it's verified and known before
1103 * we have to check map_key here. Otherwise it means
1104 * that kernel subsystem misconfigured verifier
1106 verbose("invalid map_ptr to access map->key\n");
1109 if (type
== PTR_TO_PACKET
)
1110 err
= check_packet_access(env
, regno
, 0,
1111 meta
->map_ptr
->key_size
);
1113 err
= check_stack_boundary(env
, regno
,
1114 meta
->map_ptr
->key_size
,
1116 } else if (arg_type
== ARG_PTR_TO_MAP_VALUE
) {
1117 /* bpf_map_xxx(..., map_ptr, ..., value) call:
1118 * check [value, value + map->value_size) validity
1120 if (!meta
->map_ptr
) {
1121 /* kernel subsystem misconfigured verifier */
1122 verbose("invalid map_ptr to access map->value\n");
1125 if (type
== PTR_TO_PACKET
)
1126 err
= check_packet_access(env
, regno
, 0,
1127 meta
->map_ptr
->value_size
);
1129 err
= check_stack_boundary(env
, regno
,
1130 meta
->map_ptr
->value_size
,
1132 } else if (arg_type
== ARG_CONST_SIZE
||
1133 arg_type
== ARG_CONST_SIZE_OR_ZERO
) {
1134 bool zero_size_allowed
= (arg_type
== ARG_CONST_SIZE_OR_ZERO
);
1136 /* bpf_xxx(..., buf, len) call will access 'len' bytes
1137 * from stack pointer 'buf'. Check it
1138 * note: regno == len, regno - 1 == buf
1141 /* kernel subsystem misconfigured verifier */
1142 verbose("ARG_CONST_SIZE cannot be first argument\n");
1146 /* If the register is UNKNOWN_VALUE, the access check happens
1147 * using its boundaries. Otherwise, just use its imm
1149 if (type
== UNKNOWN_VALUE
) {
1150 /* For unprivileged variable accesses, disable raw
1151 * mode so that the program is required to
1152 * initialize all the memory that the helper could
1153 * just partially fill up.
1157 if (reg
->min_value
< 0) {
1158 verbose("R%d min value is negative, either use unsigned or 'var &= const'\n",
1163 if (reg
->min_value
== 0) {
1164 err
= check_helper_mem_access(env
, regno
- 1, 0,
1171 if (reg
->max_value
== BPF_REGISTER_MAX_RANGE
) {
1172 verbose("R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
1176 err
= check_helper_mem_access(env
, regno
- 1,
1178 zero_size_allowed
, meta
);
1182 /* register is CONST_IMM */
1183 err
= check_helper_mem_access(env
, regno
- 1, reg
->imm
,
1184 zero_size_allowed
, meta
);
1190 verbose("R%d type=%s expected=%s\n", regno
,
1191 reg_type_str
[type
], reg_type_str
[expected_type
]);
1195 static int check_map_func_compatibility(struct bpf_map
*map
, int func_id
)
1200 /* We need a two way check, first is from map perspective ... */
1201 switch (map
->map_type
) {
1202 case BPF_MAP_TYPE_PROG_ARRAY
:
1203 if (func_id
!= BPF_FUNC_tail_call
)
1206 case BPF_MAP_TYPE_PERF_EVENT_ARRAY
:
1207 if (func_id
!= BPF_FUNC_perf_event_read
&&
1208 func_id
!= BPF_FUNC_perf_event_output
)
1211 case BPF_MAP_TYPE_STACK_TRACE
:
1212 if (func_id
!= BPF_FUNC_get_stackid
)
1215 case BPF_MAP_TYPE_CGROUP_ARRAY
:
1216 if (func_id
!= BPF_FUNC_skb_under_cgroup
&&
1217 func_id
!= BPF_FUNC_current_task_under_cgroup
)
1220 case BPF_MAP_TYPE_ARRAY_OF_MAPS
:
1221 case BPF_MAP_TYPE_HASH_OF_MAPS
:
1222 if (func_id
!= BPF_FUNC_map_lookup_elem
)
1228 /* ... and second from the function itself. */
1230 case BPF_FUNC_tail_call
:
1231 if (map
->map_type
!= BPF_MAP_TYPE_PROG_ARRAY
)
1234 case BPF_FUNC_perf_event_read
:
1235 case BPF_FUNC_perf_event_output
:
1236 if (map
->map_type
!= BPF_MAP_TYPE_PERF_EVENT_ARRAY
)
1239 case BPF_FUNC_get_stackid
:
1240 if (map
->map_type
!= BPF_MAP_TYPE_STACK_TRACE
)
1243 case BPF_FUNC_current_task_under_cgroup
:
1244 case BPF_FUNC_skb_under_cgroup
:
1245 if (map
->map_type
!= BPF_MAP_TYPE_CGROUP_ARRAY
)
1254 verbose("cannot pass map_type %d into func %s#%d\n",
1255 map
->map_type
, func_id_name(func_id
), func_id
);
1259 static int check_raw_mode(const struct bpf_func_proto
*fn
)
1263 if (fn
->arg1_type
== ARG_PTR_TO_UNINIT_MEM
)
1265 if (fn
->arg2_type
== ARG_PTR_TO_UNINIT_MEM
)
1267 if (fn
->arg3_type
== ARG_PTR_TO_UNINIT_MEM
)
1269 if (fn
->arg4_type
== ARG_PTR_TO_UNINIT_MEM
)
1271 if (fn
->arg5_type
== ARG_PTR_TO_UNINIT_MEM
)
1274 return count
> 1 ? -EINVAL
: 0;
1277 static void clear_all_pkt_pointers(struct bpf_verifier_env
*env
)
1279 struct bpf_verifier_state
*state
= &env
->cur_state
;
1280 struct bpf_reg_state
*regs
= state
->regs
, *reg
;
1283 for (i
= 0; i
< MAX_BPF_REG
; i
++)
1284 if (regs
[i
].type
== PTR_TO_PACKET
||
1285 regs
[i
].type
== PTR_TO_PACKET_END
)
1286 mark_reg_unknown_value(regs
, i
);
1288 for (i
= 0; i
< MAX_BPF_STACK
; i
+= BPF_REG_SIZE
) {
1289 if (state
->stack_slot_type
[i
] != STACK_SPILL
)
1291 reg
= &state
->spilled_regs
[i
/ BPF_REG_SIZE
];
1292 if (reg
->type
!= PTR_TO_PACKET
&&
1293 reg
->type
!= PTR_TO_PACKET_END
)
1295 reg
->type
= UNKNOWN_VALUE
;
1300 static int check_call(struct bpf_verifier_env
*env
, int func_id
, int insn_idx
)
1302 struct bpf_verifier_state
*state
= &env
->cur_state
;
1303 const struct bpf_func_proto
*fn
= NULL
;
1304 struct bpf_reg_state
*regs
= state
->regs
;
1305 struct bpf_reg_state
*reg
;
1306 struct bpf_call_arg_meta meta
;
1310 /* find function prototype */
1311 if (func_id
< 0 || func_id
>= __BPF_FUNC_MAX_ID
) {
1312 verbose("invalid func %s#%d\n", func_id_name(func_id
), func_id
);
1316 if (env
->prog
->aux
->ops
->get_func_proto
)
1317 fn
= env
->prog
->aux
->ops
->get_func_proto(func_id
);
1320 verbose("unknown func %s#%d\n", func_id_name(func_id
), func_id
);
1324 /* eBPF programs must be GPL compatible to use GPL-ed functions */
1325 if (!env
->prog
->gpl_compatible
&& fn
->gpl_only
) {
1326 verbose("cannot call GPL only function from proprietary program\n");
1330 changes_data
= bpf_helper_changes_pkt_data(fn
->func
);
1332 memset(&meta
, 0, sizeof(meta
));
1333 meta
.pkt_access
= fn
->pkt_access
;
1335 /* We only support one arg being in raw mode at the moment, which
1336 * is sufficient for the helper functions we have right now.
1338 err
= check_raw_mode(fn
);
1340 verbose("kernel subsystem misconfigured func %s#%d\n",
1341 func_id_name(func_id
), func_id
);
1346 err
= check_func_arg(env
, BPF_REG_1
, fn
->arg1_type
, &meta
);
1349 err
= check_func_arg(env
, BPF_REG_2
, fn
->arg2_type
, &meta
);
1352 err
= check_func_arg(env
, BPF_REG_3
, fn
->arg3_type
, &meta
);
1355 err
= check_func_arg(env
, BPF_REG_4
, fn
->arg4_type
, &meta
);
1358 err
= check_func_arg(env
, BPF_REG_5
, fn
->arg5_type
, &meta
);
1362 /* Mark slots with STACK_MISC in case of raw mode, stack offset
1363 * is inferred from register state.
1365 for (i
= 0; i
< meta
.access_size
; i
++) {
1366 err
= check_mem_access(env
, meta
.regno
, i
, BPF_B
, BPF_WRITE
, -1);
1371 /* reset caller saved regs */
1372 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
1373 reg
= regs
+ caller_saved
[i
];
1374 reg
->type
= NOT_INIT
;
1378 /* update return register */
1379 if (fn
->ret_type
== RET_INTEGER
) {
1380 regs
[BPF_REG_0
].type
= UNKNOWN_VALUE
;
1381 } else if (fn
->ret_type
== RET_VOID
) {
1382 regs
[BPF_REG_0
].type
= NOT_INIT
;
1383 } else if (fn
->ret_type
== RET_PTR_TO_MAP_VALUE_OR_NULL
) {
1384 struct bpf_insn_aux_data
*insn_aux
;
1386 regs
[BPF_REG_0
].type
= PTR_TO_MAP_VALUE_OR_NULL
;
1387 regs
[BPF_REG_0
].max_value
= regs
[BPF_REG_0
].min_value
= 0;
1388 /* remember map_ptr, so that check_map_access()
1389 * can check 'value_size' boundary of memory access
1390 * to map element returned from bpf_map_lookup_elem()
1392 if (meta
.map_ptr
== NULL
) {
1393 verbose("kernel subsystem misconfigured verifier\n");
1396 regs
[BPF_REG_0
].map_ptr
= meta
.map_ptr
;
1397 regs
[BPF_REG_0
].id
= ++env
->id_gen
;
1398 insn_aux
= &env
->insn_aux_data
[insn_idx
];
1399 if (!insn_aux
->map_ptr
)
1400 insn_aux
->map_ptr
= meta
.map_ptr
;
1401 else if (insn_aux
->map_ptr
!= meta
.map_ptr
)
1402 insn_aux
->map_ptr
= BPF_MAP_PTR_POISON
;
1404 verbose("unknown return type %d of func %s#%d\n",
1405 fn
->ret_type
, func_id_name(func_id
), func_id
);
1409 err
= check_map_func_compatibility(meta
.map_ptr
, func_id
);
1414 clear_all_pkt_pointers(env
);
1418 static int check_packet_ptr_add(struct bpf_verifier_env
*env
,
1419 struct bpf_insn
*insn
)
1421 struct bpf_reg_state
*regs
= env
->cur_state
.regs
;
1422 struct bpf_reg_state
*dst_reg
= ®s
[insn
->dst_reg
];
1423 struct bpf_reg_state
*src_reg
= ®s
[insn
->src_reg
];
1424 struct bpf_reg_state tmp_reg
;
1427 if (BPF_SRC(insn
->code
) == BPF_K
) {
1428 /* pkt_ptr += imm */
1433 verbose("addition of negative constant to packet pointer is not allowed\n");
1436 if (imm
>= MAX_PACKET_OFF
||
1437 imm
+ dst_reg
->off
>= MAX_PACKET_OFF
) {
1438 verbose("constant %d is too large to add to packet pointer\n",
1442 /* a constant was added to pkt_ptr.
1443 * Remember it while keeping the same 'id'
1445 dst_reg
->off
+= imm
;
1447 if (src_reg
->type
== PTR_TO_PACKET
) {
1448 /* R6=pkt(id=0,off=0,r=62) R7=imm22; r7 += r6 */
1449 tmp_reg
= *dst_reg
; /* save r7 state */
1450 *dst_reg
= *src_reg
; /* copy pkt_ptr state r6 into r7 */
1451 src_reg
= &tmp_reg
; /* pretend it's src_reg state */
1452 /* if the checks below reject it, the copy won't matter,
1453 * since we're rejecting the whole program. If all ok,
1454 * then imm22 state will be added to r7
1455 * and r7 will be pkt(id=0,off=22,r=62) while
1456 * r6 will stay as pkt(id=0,off=0,r=62)
1460 if (src_reg
->type
== CONST_IMM
) {
1461 /* pkt_ptr += reg where reg is known constant */
1465 /* disallow pkt_ptr += reg
1466 * if reg is not uknown_value with guaranteed zero upper bits
1467 * otherwise pkt_ptr may overflow and addition will become
1468 * subtraction which is not allowed
1470 if (src_reg
->type
!= UNKNOWN_VALUE
) {
1471 verbose("cannot add '%s' to ptr_to_packet\n",
1472 reg_type_str
[src_reg
->type
]);
1475 if (src_reg
->imm
< 48) {
1476 verbose("cannot add integer value with %lld upper zero bits to ptr_to_packet\n",
1480 /* dst_reg stays as pkt_ptr type and since some positive
1481 * integer value was added to the pointer, increment its 'id'
1483 dst_reg
->id
= ++env
->id_gen
;
1485 /* something was added to pkt_ptr, set range and off to zero */
1492 static int evaluate_reg_alu(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
1494 struct bpf_reg_state
*regs
= env
->cur_state
.regs
;
1495 struct bpf_reg_state
*dst_reg
= ®s
[insn
->dst_reg
];
1496 u8 opcode
= BPF_OP(insn
->code
);
1499 /* for type == UNKNOWN_VALUE:
1500 * imm > 0 -> number of zero upper bits
1501 * imm == 0 -> don't track which is the same as all bits can be non-zero
1504 if (BPF_SRC(insn
->code
) == BPF_X
) {
1505 struct bpf_reg_state
*src_reg
= ®s
[insn
->src_reg
];
1507 if (src_reg
->type
== UNKNOWN_VALUE
&& src_reg
->imm
> 0 &&
1508 dst_reg
->imm
&& opcode
== BPF_ADD
) {
1510 * where both have zero upper bits. Adding them
1511 * can only result making one more bit non-zero
1512 * in the larger value.
1513 * Ex. 0xffff (imm=48) + 1 (imm=63) = 0x10000 (imm=47)
1514 * 0xffff (imm=48) + 0xffff = 0x1fffe (imm=47)
1516 dst_reg
->imm
= min(dst_reg
->imm
, src_reg
->imm
);
1520 if (src_reg
->type
== CONST_IMM
&& src_reg
->imm
> 0 &&
1521 dst_reg
->imm
&& opcode
== BPF_ADD
) {
1523 * where dreg has zero upper bits and sreg is const.
1524 * Adding them can only result making one more bit
1525 * non-zero in the larger value.
1527 imm_log2
= __ilog2_u64((long long)src_reg
->imm
);
1528 dst_reg
->imm
= min(dst_reg
->imm
, 63 - imm_log2
);
1532 /* all other cases non supported yet, just mark dst_reg */
1537 /* sign extend 32-bit imm into 64-bit to make sure that
1538 * negative values occupy bit 63. Note ilog2() would have
1539 * been incorrect, since sizeof(insn->imm) == 4
1541 imm_log2
= __ilog2_u64((long long)insn
->imm
);
1543 if (dst_reg
->imm
&& opcode
== BPF_LSH
) {
1545 * if reg was a result of 2 byte load, then its imm == 48
1546 * which means that upper 48 bits are zero and shifting this reg
1547 * left by 4 would mean that upper 44 bits are still zero
1549 dst_reg
->imm
-= insn
->imm
;
1550 } else if (dst_reg
->imm
&& opcode
== BPF_MUL
) {
1552 * if multiplying by 14 subtract 4
1553 * This is conservative calculation of upper zero bits.
1554 * It's not trying to special case insn->imm == 1 or 0 cases
1556 dst_reg
->imm
-= imm_log2
+ 1;
1557 } else if (opcode
== BPF_AND
) {
1559 dst_reg
->imm
= 63 - imm_log2
;
1560 } else if (dst_reg
->imm
&& opcode
== BPF_ADD
) {
1562 dst_reg
->imm
= min(dst_reg
->imm
, 63 - imm_log2
);
1564 } else if (opcode
== BPF_RSH
) {
1566 * which means that after right shift, upper bits will be zero
1567 * note that verifier already checked that
1568 * 0 <= imm < 64 for shift insn
1570 dst_reg
->imm
+= insn
->imm
;
1571 if (unlikely(dst_reg
->imm
> 64))
1572 /* some dumb code did:
1575 * and all bits are zero now */
1578 /* all other alu ops, means that we don't know what will
1579 * happen to the value, mark it with unknown number of zero bits
1584 if (dst_reg
->imm
< 0) {
1585 /* all 64 bits of the register can contain non-zero bits
1586 * and such value cannot be added to ptr_to_packet, since it
1587 * may overflow, mark it as unknown to avoid further eval
1594 static int evaluate_reg_imm_alu(struct bpf_verifier_env
*env
,
1595 struct bpf_insn
*insn
)
1597 struct bpf_reg_state
*regs
= env
->cur_state
.regs
;
1598 struct bpf_reg_state
*dst_reg
= ®s
[insn
->dst_reg
];
1599 struct bpf_reg_state
*src_reg
= ®s
[insn
->src_reg
];
1600 u8 opcode
= BPF_OP(insn
->code
);
1601 u64 dst_imm
= dst_reg
->imm
;
1603 /* dst_reg->type == CONST_IMM here. Simulate execution of insns
1604 * containing ALU ops. Don't care about overflow or negative
1605 * values, just add/sub/... them; registers are in u64.
1607 if (opcode
== BPF_ADD
&& BPF_SRC(insn
->code
) == BPF_K
) {
1608 dst_imm
+= insn
->imm
;
1609 } else if (opcode
== BPF_ADD
&& BPF_SRC(insn
->code
) == BPF_X
&&
1610 src_reg
->type
== CONST_IMM
) {
1611 dst_imm
+= src_reg
->imm
;
1612 } else if (opcode
== BPF_SUB
&& BPF_SRC(insn
->code
) == BPF_K
) {
1613 dst_imm
-= insn
->imm
;
1614 } else if (opcode
== BPF_SUB
&& BPF_SRC(insn
->code
) == BPF_X
&&
1615 src_reg
->type
== CONST_IMM
) {
1616 dst_imm
-= src_reg
->imm
;
1617 } else if (opcode
== BPF_MUL
&& BPF_SRC(insn
->code
) == BPF_K
) {
1618 dst_imm
*= insn
->imm
;
1619 } else if (opcode
== BPF_MUL
&& BPF_SRC(insn
->code
) == BPF_X
&&
1620 src_reg
->type
== CONST_IMM
) {
1621 dst_imm
*= src_reg
->imm
;
1622 } else if (opcode
== BPF_OR
&& BPF_SRC(insn
->code
) == BPF_K
) {
1623 dst_imm
|= insn
->imm
;
1624 } else if (opcode
== BPF_OR
&& BPF_SRC(insn
->code
) == BPF_X
&&
1625 src_reg
->type
== CONST_IMM
) {
1626 dst_imm
|= src_reg
->imm
;
1627 } else if (opcode
== BPF_AND
&& BPF_SRC(insn
->code
) == BPF_K
) {
1628 dst_imm
&= insn
->imm
;
1629 } else if (opcode
== BPF_AND
&& BPF_SRC(insn
->code
) == BPF_X
&&
1630 src_reg
->type
== CONST_IMM
) {
1631 dst_imm
&= src_reg
->imm
;
1632 } else if (opcode
== BPF_RSH
&& BPF_SRC(insn
->code
) == BPF_K
) {
1633 dst_imm
>>= insn
->imm
;
1634 } else if (opcode
== BPF_RSH
&& BPF_SRC(insn
->code
) == BPF_X
&&
1635 src_reg
->type
== CONST_IMM
) {
1636 dst_imm
>>= src_reg
->imm
;
1637 } else if (opcode
== BPF_LSH
&& BPF_SRC(insn
->code
) == BPF_K
) {
1638 dst_imm
<<= insn
->imm
;
1639 } else if (opcode
== BPF_LSH
&& BPF_SRC(insn
->code
) == BPF_X
&&
1640 src_reg
->type
== CONST_IMM
) {
1641 dst_imm
<<= src_reg
->imm
;
1643 mark_reg_unknown_value(regs
, insn
->dst_reg
);
1647 dst_reg
->imm
= dst_imm
;
1652 static void check_reg_overflow(struct bpf_reg_state
*reg
)
1654 if (reg
->max_value
> BPF_REGISTER_MAX_RANGE
)
1655 reg
->max_value
= BPF_REGISTER_MAX_RANGE
;
1656 if (reg
->min_value
< BPF_REGISTER_MIN_RANGE
||
1657 reg
->min_value
> BPF_REGISTER_MAX_RANGE
)
1658 reg
->min_value
= BPF_REGISTER_MIN_RANGE
;
1661 static void adjust_reg_min_max_vals(struct bpf_verifier_env
*env
,
1662 struct bpf_insn
*insn
)
1664 struct bpf_reg_state
*regs
= env
->cur_state
.regs
, *dst_reg
;
1665 s64 min_val
= BPF_REGISTER_MIN_RANGE
;
1666 u64 max_val
= BPF_REGISTER_MAX_RANGE
;
1667 u8 opcode
= BPF_OP(insn
->code
);
1669 dst_reg
= ®s
[insn
->dst_reg
];
1670 if (BPF_SRC(insn
->code
) == BPF_X
) {
1671 check_reg_overflow(®s
[insn
->src_reg
]);
1672 min_val
= regs
[insn
->src_reg
].min_value
;
1673 max_val
= regs
[insn
->src_reg
].max_value
;
1675 /* If the source register is a random pointer then the
1676 * min_value/max_value values represent the range of the known
1677 * accesses into that value, not the actual min/max value of the
1678 * register itself. In this case we have to reset the reg range
1679 * values so we know it is not safe to look at.
1681 if (regs
[insn
->src_reg
].type
!= CONST_IMM
&&
1682 regs
[insn
->src_reg
].type
!= UNKNOWN_VALUE
) {
1683 min_val
= BPF_REGISTER_MIN_RANGE
;
1684 max_val
= BPF_REGISTER_MAX_RANGE
;
1686 } else if (insn
->imm
< BPF_REGISTER_MAX_RANGE
&&
1687 (s64
)insn
->imm
> BPF_REGISTER_MIN_RANGE
) {
1688 min_val
= max_val
= insn
->imm
;
1691 /* We don't know anything about what was done to this register, mark it
1694 if (min_val
== BPF_REGISTER_MIN_RANGE
&&
1695 max_val
== BPF_REGISTER_MAX_RANGE
) {
1696 reset_reg_range_values(regs
, insn
->dst_reg
);
1700 /* If one of our values was at the end of our ranges then we can't just
1701 * do our normal operations to the register, we need to set the values
1702 * to the min/max since they are undefined.
1704 if (min_val
== BPF_REGISTER_MIN_RANGE
)
1705 dst_reg
->min_value
= BPF_REGISTER_MIN_RANGE
;
1706 if (max_val
== BPF_REGISTER_MAX_RANGE
)
1707 dst_reg
->max_value
= BPF_REGISTER_MAX_RANGE
;
1711 if (dst_reg
->min_value
!= BPF_REGISTER_MIN_RANGE
)
1712 dst_reg
->min_value
+= min_val
;
1713 if (dst_reg
->max_value
!= BPF_REGISTER_MAX_RANGE
)
1714 dst_reg
->max_value
+= max_val
;
1717 if (dst_reg
->min_value
!= BPF_REGISTER_MIN_RANGE
)
1718 dst_reg
->min_value
-= min_val
;
1719 if (dst_reg
->max_value
!= BPF_REGISTER_MAX_RANGE
)
1720 dst_reg
->max_value
-= max_val
;
1723 if (dst_reg
->min_value
!= BPF_REGISTER_MIN_RANGE
)
1724 dst_reg
->min_value
*= min_val
;
1725 if (dst_reg
->max_value
!= BPF_REGISTER_MAX_RANGE
)
1726 dst_reg
->max_value
*= max_val
;
1729 /* Disallow AND'ing of negative numbers, ain't nobody got time
1730 * for that. Otherwise the minimum is 0 and the max is the max
1731 * value we could AND against.
1734 dst_reg
->min_value
= BPF_REGISTER_MIN_RANGE
;
1736 dst_reg
->min_value
= 0;
1737 dst_reg
->max_value
= max_val
;
1740 /* Gotta have special overflow logic here, if we're shifting
1741 * more than MAX_RANGE then just assume we have an invalid
1744 if (min_val
> ilog2(BPF_REGISTER_MAX_RANGE
))
1745 dst_reg
->min_value
= BPF_REGISTER_MIN_RANGE
;
1746 else if (dst_reg
->min_value
!= BPF_REGISTER_MIN_RANGE
)
1747 dst_reg
->min_value
<<= min_val
;
1749 if (max_val
> ilog2(BPF_REGISTER_MAX_RANGE
))
1750 dst_reg
->max_value
= BPF_REGISTER_MAX_RANGE
;
1751 else if (dst_reg
->max_value
!= BPF_REGISTER_MAX_RANGE
)
1752 dst_reg
->max_value
<<= max_val
;
1755 /* RSH by a negative number is undefined, and the BPF_RSH is an
1756 * unsigned shift, so make the appropriate casts.
1758 if (min_val
< 0 || dst_reg
->min_value
< 0)
1759 dst_reg
->min_value
= BPF_REGISTER_MIN_RANGE
;
1761 dst_reg
->min_value
=
1762 (u64
)(dst_reg
->min_value
) >> min_val
;
1763 if (dst_reg
->max_value
!= BPF_REGISTER_MAX_RANGE
)
1764 dst_reg
->max_value
>>= max_val
;
1767 reset_reg_range_values(regs
, insn
->dst_reg
);
1771 check_reg_overflow(dst_reg
);
1774 /* check validity of 32-bit and 64-bit arithmetic operations */
1775 static int check_alu_op(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
1777 struct bpf_reg_state
*regs
= env
->cur_state
.regs
, *dst_reg
;
1778 u8 opcode
= BPF_OP(insn
->code
);
1781 if (opcode
== BPF_END
|| opcode
== BPF_NEG
) {
1782 if (opcode
== BPF_NEG
) {
1783 if (BPF_SRC(insn
->code
) != 0 ||
1784 insn
->src_reg
!= BPF_REG_0
||
1785 insn
->off
!= 0 || insn
->imm
!= 0) {
1786 verbose("BPF_NEG uses reserved fields\n");
1790 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0 ||
1791 (insn
->imm
!= 16 && insn
->imm
!= 32 && insn
->imm
!= 64)) {
1792 verbose("BPF_END uses reserved fields\n");
1797 /* check src operand */
1798 err
= check_reg_arg(regs
, insn
->dst_reg
, SRC_OP
);
1802 if (is_pointer_value(env
, insn
->dst_reg
)) {
1803 verbose("R%d pointer arithmetic prohibited\n",
1808 /* check dest operand */
1809 err
= check_reg_arg(regs
, insn
->dst_reg
, DST_OP
);
1813 } else if (opcode
== BPF_MOV
) {
1815 if (BPF_SRC(insn
->code
) == BPF_X
) {
1816 if (insn
->imm
!= 0 || insn
->off
!= 0) {
1817 verbose("BPF_MOV uses reserved fields\n");
1821 /* check src operand */
1822 err
= check_reg_arg(regs
, insn
->src_reg
, SRC_OP
);
1826 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0) {
1827 verbose("BPF_MOV uses reserved fields\n");
1832 /* check dest operand */
1833 err
= check_reg_arg(regs
, insn
->dst_reg
, DST_OP
);
1837 /* we are setting our register to something new, we need to
1838 * reset its range values.
1840 reset_reg_range_values(regs
, insn
->dst_reg
);
1842 if (BPF_SRC(insn
->code
) == BPF_X
) {
1843 if (BPF_CLASS(insn
->code
) == BPF_ALU64
) {
1845 * copy register state to dest reg
1847 regs
[insn
->dst_reg
] = regs
[insn
->src_reg
];
1849 if (is_pointer_value(env
, insn
->src_reg
)) {
1850 verbose("R%d partial copy of pointer\n",
1854 mark_reg_unknown_value(regs
, insn
->dst_reg
);
1858 * remember the value we stored into this reg
1860 regs
[insn
->dst_reg
].type
= CONST_IMM
;
1861 regs
[insn
->dst_reg
].imm
= insn
->imm
;
1862 regs
[insn
->dst_reg
].max_value
= insn
->imm
;
1863 regs
[insn
->dst_reg
].min_value
= insn
->imm
;
1866 } else if (opcode
> BPF_END
) {
1867 verbose("invalid BPF_ALU opcode %x\n", opcode
);
1870 } else { /* all other ALU ops: and, sub, xor, add, ... */
1872 if (BPF_SRC(insn
->code
) == BPF_X
) {
1873 if (insn
->imm
!= 0 || insn
->off
!= 0) {
1874 verbose("BPF_ALU uses reserved fields\n");
1877 /* check src1 operand */
1878 err
= check_reg_arg(regs
, insn
->src_reg
, SRC_OP
);
1882 if (insn
->src_reg
!= BPF_REG_0
|| insn
->off
!= 0) {
1883 verbose("BPF_ALU uses reserved fields\n");
1888 /* check src2 operand */
1889 err
= check_reg_arg(regs
, insn
->dst_reg
, SRC_OP
);
1893 if ((opcode
== BPF_MOD
|| opcode
== BPF_DIV
) &&
1894 BPF_SRC(insn
->code
) == BPF_K
&& insn
->imm
== 0) {
1895 verbose("div by zero\n");
1899 if ((opcode
== BPF_LSH
|| opcode
== BPF_RSH
||
1900 opcode
== BPF_ARSH
) && BPF_SRC(insn
->code
) == BPF_K
) {
1901 int size
= BPF_CLASS(insn
->code
) == BPF_ALU64
? 64 : 32;
1903 if (insn
->imm
< 0 || insn
->imm
>= size
) {
1904 verbose("invalid shift %d\n", insn
->imm
);
1909 /* check dest operand */
1910 err
= check_reg_arg(regs
, insn
->dst_reg
, DST_OP_NO_MARK
);
1914 dst_reg
= ®s
[insn
->dst_reg
];
1916 /* first we want to adjust our ranges. */
1917 adjust_reg_min_max_vals(env
, insn
);
1919 /* pattern match 'bpf_add Rx, imm' instruction */
1920 if (opcode
== BPF_ADD
&& BPF_CLASS(insn
->code
) == BPF_ALU64
&&
1921 dst_reg
->type
== FRAME_PTR
&& BPF_SRC(insn
->code
) == BPF_K
) {
1922 dst_reg
->type
= PTR_TO_STACK
;
1923 dst_reg
->imm
= insn
->imm
;
1925 } else if (opcode
== BPF_ADD
&&
1926 BPF_CLASS(insn
->code
) == BPF_ALU64
&&
1927 dst_reg
->type
== PTR_TO_STACK
&&
1928 ((BPF_SRC(insn
->code
) == BPF_X
&&
1929 regs
[insn
->src_reg
].type
== CONST_IMM
) ||
1930 BPF_SRC(insn
->code
) == BPF_K
)) {
1931 if (BPF_SRC(insn
->code
) == BPF_X
)
1932 dst_reg
->imm
+= regs
[insn
->src_reg
].imm
;
1934 dst_reg
->imm
+= insn
->imm
;
1936 } else if (opcode
== BPF_ADD
&&
1937 BPF_CLASS(insn
->code
) == BPF_ALU64
&&
1938 (dst_reg
->type
== PTR_TO_PACKET
||
1939 (BPF_SRC(insn
->code
) == BPF_X
&&
1940 regs
[insn
->src_reg
].type
== PTR_TO_PACKET
))) {
1941 /* ptr_to_packet += K|X */
1942 return check_packet_ptr_add(env
, insn
);
1943 } else if (BPF_CLASS(insn
->code
) == BPF_ALU64
&&
1944 dst_reg
->type
== UNKNOWN_VALUE
&&
1945 env
->allow_ptr_leaks
) {
1946 /* unknown += K|X */
1947 return evaluate_reg_alu(env
, insn
);
1948 } else if (BPF_CLASS(insn
->code
) == BPF_ALU64
&&
1949 dst_reg
->type
== CONST_IMM
&&
1950 env
->allow_ptr_leaks
) {
1951 /* reg_imm += K|X */
1952 return evaluate_reg_imm_alu(env
, insn
);
1953 } else if (is_pointer_value(env
, insn
->dst_reg
)) {
1954 verbose("R%d pointer arithmetic prohibited\n",
1957 } else if (BPF_SRC(insn
->code
) == BPF_X
&&
1958 is_pointer_value(env
, insn
->src_reg
)) {
1959 verbose("R%d pointer arithmetic prohibited\n",
1964 /* If we did pointer math on a map value then just set it to our
1965 * PTR_TO_MAP_VALUE_ADJ type so we can deal with any stores or
1966 * loads to this register appropriately, otherwise just mark the
1967 * register as unknown.
1969 if (env
->allow_ptr_leaks
&&
1970 BPF_CLASS(insn
->code
) == BPF_ALU64
&& opcode
== BPF_ADD
&&
1971 (dst_reg
->type
== PTR_TO_MAP_VALUE
||
1972 dst_reg
->type
== PTR_TO_MAP_VALUE_ADJ
))
1973 dst_reg
->type
= PTR_TO_MAP_VALUE_ADJ
;
1975 mark_reg_unknown_value(regs
, insn
->dst_reg
);
1981 static void find_good_pkt_pointers(struct bpf_verifier_state
*state
,
1982 struct bpf_reg_state
*dst_reg
)
1984 struct bpf_reg_state
*regs
= state
->regs
, *reg
;
1987 /* LLVM can generate two kind of checks:
1993 * if (r2 > pkt_end) goto <handle exception>
1997 * r2 == dst_reg, pkt_end == src_reg
1998 * r2=pkt(id=n,off=8,r=0)
1999 * r3=pkt(id=n,off=0,r=0)
2005 * if (pkt_end >= r2) goto <access okay>
2006 * <handle exception>
2009 * pkt_end == dst_reg, r2 == src_reg
2010 * r2=pkt(id=n,off=8,r=0)
2011 * r3=pkt(id=n,off=0,r=0)
2013 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
2014 * so that range of bytes [r3, r3 + 8) is safe to access.
2017 for (i
= 0; i
< MAX_BPF_REG
; i
++)
2018 if (regs
[i
].type
== PTR_TO_PACKET
&& regs
[i
].id
== dst_reg
->id
)
2019 /* keep the maximum range already checked */
2020 regs
[i
].range
= max(regs
[i
].range
, dst_reg
->off
);
2022 for (i
= 0; i
< MAX_BPF_STACK
; i
+= BPF_REG_SIZE
) {
2023 if (state
->stack_slot_type
[i
] != STACK_SPILL
)
2025 reg
= &state
->spilled_regs
[i
/ BPF_REG_SIZE
];
2026 if (reg
->type
== PTR_TO_PACKET
&& reg
->id
== dst_reg
->id
)
2027 reg
->range
= max(reg
->range
, dst_reg
->off
);
2031 /* Adjusts the register min/max values in the case that the dst_reg is the
2032 * variable register that we are working on, and src_reg is a constant or we're
2033 * simply doing a BPF_K check.
2035 static void reg_set_min_max(struct bpf_reg_state
*true_reg
,
2036 struct bpf_reg_state
*false_reg
, u64 val
,
2041 /* If this is false then we know nothing Jon Snow, but if it is
2042 * true then we know for sure.
2044 true_reg
->max_value
= true_reg
->min_value
= val
;
2047 /* If this is true we know nothing Jon Snow, but if it is false
2048 * we know the value for sure;
2050 false_reg
->max_value
= false_reg
->min_value
= val
;
2053 /* Unsigned comparison, the minimum value is 0. */
2054 false_reg
->min_value
= 0;
2057 /* If this is false then we know the maximum val is val,
2058 * otherwise we know the min val is val+1.
2060 false_reg
->max_value
= val
;
2061 true_reg
->min_value
= val
+ 1;
2064 /* Unsigned comparison, the minimum value is 0. */
2065 false_reg
->min_value
= 0;
2068 /* If this is false then we know the maximum value is val - 1,
2069 * otherwise we know the mimimum value is val.
2071 false_reg
->max_value
= val
- 1;
2072 true_reg
->min_value
= val
;
2078 check_reg_overflow(false_reg
);
2079 check_reg_overflow(true_reg
);
2082 /* Same as above, but for the case that dst_reg is a CONST_IMM reg and src_reg
2083 * is the variable reg.
2085 static void reg_set_min_max_inv(struct bpf_reg_state
*true_reg
,
2086 struct bpf_reg_state
*false_reg
, u64 val
,
2091 /* If this is false then we know nothing Jon Snow, but if it is
2092 * true then we know for sure.
2094 true_reg
->max_value
= true_reg
->min_value
= val
;
2097 /* If this is true we know nothing Jon Snow, but if it is false
2098 * we know the value for sure;
2100 false_reg
->max_value
= false_reg
->min_value
= val
;
2103 /* Unsigned comparison, the minimum value is 0. */
2104 true_reg
->min_value
= 0;
2108 * If this is false, then the val is <= the register, if it is
2109 * true the register <= to the val.
2111 false_reg
->min_value
= val
;
2112 true_reg
->max_value
= val
- 1;
2115 /* Unsigned comparison, the minimum value is 0. */
2116 true_reg
->min_value
= 0;
2119 /* If this is false then constant < register, if it is true then
2120 * the register < constant.
2122 false_reg
->min_value
= val
+ 1;
2123 true_reg
->max_value
= val
;
2129 check_reg_overflow(false_reg
);
2130 check_reg_overflow(true_reg
);
2133 static void mark_map_reg(struct bpf_reg_state
*regs
, u32 regno
, u32 id
,
2134 enum bpf_reg_type type
)
2136 struct bpf_reg_state
*reg
= ®s
[regno
];
2138 if (reg
->type
== PTR_TO_MAP_VALUE_OR_NULL
&& reg
->id
== id
) {
2139 if (type
== UNKNOWN_VALUE
) {
2140 __mark_reg_unknown_value(regs
, regno
);
2141 } else if (reg
->map_ptr
->inner_map_meta
) {
2142 reg
->type
= CONST_PTR_TO_MAP
;
2143 reg
->map_ptr
= reg
->map_ptr
->inner_map_meta
;
2147 /* We don't need id from this point onwards anymore, thus we
2148 * should better reset it, so that state pruning has chances
2155 /* The logic is similar to find_good_pkt_pointers(), both could eventually
2156 * be folded together at some point.
2158 static void mark_map_regs(struct bpf_verifier_state
*state
, u32 regno
,
2159 enum bpf_reg_type type
)
2161 struct bpf_reg_state
*regs
= state
->regs
;
2162 u32 id
= regs
[regno
].id
;
2165 for (i
= 0; i
< MAX_BPF_REG
; i
++)
2166 mark_map_reg(regs
, i
, id
, type
);
2168 for (i
= 0; i
< MAX_BPF_STACK
; i
+= BPF_REG_SIZE
) {
2169 if (state
->stack_slot_type
[i
] != STACK_SPILL
)
2171 mark_map_reg(state
->spilled_regs
, i
/ BPF_REG_SIZE
, id
, type
);
2175 static int check_cond_jmp_op(struct bpf_verifier_env
*env
,
2176 struct bpf_insn
*insn
, int *insn_idx
)
2178 struct bpf_verifier_state
*other_branch
, *this_branch
= &env
->cur_state
;
2179 struct bpf_reg_state
*regs
= this_branch
->regs
, *dst_reg
;
2180 u8 opcode
= BPF_OP(insn
->code
);
2183 if (opcode
> BPF_EXIT
) {
2184 verbose("invalid BPF_JMP opcode %x\n", opcode
);
2188 if (BPF_SRC(insn
->code
) == BPF_X
) {
2189 if (insn
->imm
!= 0) {
2190 verbose("BPF_JMP uses reserved fields\n");
2194 /* check src1 operand */
2195 err
= check_reg_arg(regs
, insn
->src_reg
, SRC_OP
);
2199 if (is_pointer_value(env
, insn
->src_reg
)) {
2200 verbose("R%d pointer comparison prohibited\n",
2205 if (insn
->src_reg
!= BPF_REG_0
) {
2206 verbose("BPF_JMP uses reserved fields\n");
2211 /* check src2 operand */
2212 err
= check_reg_arg(regs
, insn
->dst_reg
, SRC_OP
);
2216 dst_reg
= ®s
[insn
->dst_reg
];
2218 /* detect if R == 0 where R was initialized to zero earlier */
2219 if (BPF_SRC(insn
->code
) == BPF_K
&&
2220 (opcode
== BPF_JEQ
|| opcode
== BPF_JNE
) &&
2221 dst_reg
->type
== CONST_IMM
&& dst_reg
->imm
== insn
->imm
) {
2222 if (opcode
== BPF_JEQ
) {
2223 /* if (imm == imm) goto pc+off;
2224 * only follow the goto, ignore fall-through
2226 *insn_idx
+= insn
->off
;
2229 /* if (imm != imm) goto pc+off;
2230 * only follow fall-through branch, since
2231 * that's where the program will go
2237 other_branch
= push_stack(env
, *insn_idx
+ insn
->off
+ 1, *insn_idx
);
2241 /* detect if we are comparing against a constant value so we can adjust
2242 * our min/max values for our dst register.
2244 if (BPF_SRC(insn
->code
) == BPF_X
) {
2245 if (regs
[insn
->src_reg
].type
== CONST_IMM
)
2246 reg_set_min_max(&other_branch
->regs
[insn
->dst_reg
],
2247 dst_reg
, regs
[insn
->src_reg
].imm
,
2249 else if (dst_reg
->type
== CONST_IMM
)
2250 reg_set_min_max_inv(&other_branch
->regs
[insn
->src_reg
],
2251 ®s
[insn
->src_reg
], dst_reg
->imm
,
2254 reg_set_min_max(&other_branch
->regs
[insn
->dst_reg
],
2255 dst_reg
, insn
->imm
, opcode
);
2258 /* detect if R == 0 where R is returned from bpf_map_lookup_elem() */
2259 if (BPF_SRC(insn
->code
) == BPF_K
&&
2260 insn
->imm
== 0 && (opcode
== BPF_JEQ
|| opcode
== BPF_JNE
) &&
2261 dst_reg
->type
== PTR_TO_MAP_VALUE_OR_NULL
) {
2262 /* Mark all identical map registers in each branch as either
2263 * safe or unknown depending R == 0 or R != 0 conditional.
2265 mark_map_regs(this_branch
, insn
->dst_reg
,
2266 opcode
== BPF_JEQ
? PTR_TO_MAP_VALUE
: UNKNOWN_VALUE
);
2267 mark_map_regs(other_branch
, insn
->dst_reg
,
2268 opcode
== BPF_JEQ
? UNKNOWN_VALUE
: PTR_TO_MAP_VALUE
);
2269 } else if (BPF_SRC(insn
->code
) == BPF_X
&& opcode
== BPF_JGT
&&
2270 dst_reg
->type
== PTR_TO_PACKET
&&
2271 regs
[insn
->src_reg
].type
== PTR_TO_PACKET_END
) {
2272 find_good_pkt_pointers(this_branch
, dst_reg
);
2273 } else if (BPF_SRC(insn
->code
) == BPF_X
&& opcode
== BPF_JGE
&&
2274 dst_reg
->type
== PTR_TO_PACKET_END
&&
2275 regs
[insn
->src_reg
].type
== PTR_TO_PACKET
) {
2276 find_good_pkt_pointers(other_branch
, ®s
[insn
->src_reg
]);
2277 } else if (is_pointer_value(env
, insn
->dst_reg
)) {
2278 verbose("R%d pointer comparison prohibited\n", insn
->dst_reg
);
2282 print_verifier_state(this_branch
);
2286 /* return the map pointer stored inside BPF_LD_IMM64 instruction */
2287 static struct bpf_map
*ld_imm64_to_map_ptr(struct bpf_insn
*insn
)
2289 u64 imm64
= ((u64
) (u32
) insn
[0].imm
) | ((u64
) (u32
) insn
[1].imm
) << 32;
2291 return (struct bpf_map
*) (unsigned long) imm64
;
2294 /* verify BPF_LD_IMM64 instruction */
2295 static int check_ld_imm(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
2297 struct bpf_reg_state
*regs
= env
->cur_state
.regs
;
2300 if (BPF_SIZE(insn
->code
) != BPF_DW
) {
2301 verbose("invalid BPF_LD_IMM insn\n");
2304 if (insn
->off
!= 0) {
2305 verbose("BPF_LD_IMM64 uses reserved fields\n");
2309 err
= check_reg_arg(regs
, insn
->dst_reg
, DST_OP
);
2313 if (insn
->src_reg
== 0) {
2314 u64 imm
= ((u64
)(insn
+ 1)->imm
<< 32) | (u32
)insn
->imm
;
2316 regs
[insn
->dst_reg
].type
= CONST_IMM
;
2317 regs
[insn
->dst_reg
].imm
= imm
;
2321 /* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */
2322 BUG_ON(insn
->src_reg
!= BPF_PSEUDO_MAP_FD
);
2324 regs
[insn
->dst_reg
].type
= CONST_PTR_TO_MAP
;
2325 regs
[insn
->dst_reg
].map_ptr
= ld_imm64_to_map_ptr(insn
);
2329 static bool may_access_skb(enum bpf_prog_type type
)
2332 case BPF_PROG_TYPE_SOCKET_FILTER
:
2333 case BPF_PROG_TYPE_SCHED_CLS
:
2334 case BPF_PROG_TYPE_SCHED_ACT
:
2341 /* verify safety of LD_ABS|LD_IND instructions:
2342 * - they can only appear in the programs where ctx == skb
2343 * - since they are wrappers of function calls, they scratch R1-R5 registers,
2344 * preserve R6-R9, and store return value into R0
2347 * ctx == skb == R6 == CTX
2350 * SRC == any register
2351 * IMM == 32-bit immediate
2354 * R0 - 8/16/32-bit skb data converted to cpu endianness
2356 static int check_ld_abs(struct bpf_verifier_env
*env
, struct bpf_insn
*insn
)
2358 struct bpf_reg_state
*regs
= env
->cur_state
.regs
;
2359 u8 mode
= BPF_MODE(insn
->code
);
2360 struct bpf_reg_state
*reg
;
2363 if (!may_access_skb(env
->prog
->type
)) {
2364 verbose("BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
2368 if (insn
->dst_reg
!= BPF_REG_0
|| insn
->off
!= 0 ||
2369 BPF_SIZE(insn
->code
) == BPF_DW
||
2370 (mode
== BPF_ABS
&& insn
->src_reg
!= BPF_REG_0
)) {
2371 verbose("BPF_LD_[ABS|IND] uses reserved fields\n");
2375 /* check whether implicit source operand (register R6) is readable */
2376 err
= check_reg_arg(regs
, BPF_REG_6
, SRC_OP
);
2380 if (regs
[BPF_REG_6
].type
!= PTR_TO_CTX
) {
2381 verbose("at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
2385 if (mode
== BPF_IND
) {
2386 /* check explicit source operand */
2387 err
= check_reg_arg(regs
, insn
->src_reg
, SRC_OP
);
2392 /* reset caller saved regs to unreadable */
2393 for (i
= 0; i
< CALLER_SAVED_REGS
; i
++) {
2394 reg
= regs
+ caller_saved
[i
];
2395 reg
->type
= NOT_INIT
;
2399 /* mark destination R0 register as readable, since it contains
2400 * the value fetched from the packet
2402 regs
[BPF_REG_0
].type
= UNKNOWN_VALUE
;
2406 /* non-recursive DFS pseudo code
2407 * 1 procedure DFS-iterative(G,v):
2408 * 2 label v as discovered
2409 * 3 let S be a stack
2411 * 5 while S is not empty
2413 * 7 if t is what we're looking for:
2415 * 9 for all edges e in G.adjacentEdges(t) do
2416 * 10 if edge e is already labelled
2417 * 11 continue with the next edge
2418 * 12 w <- G.adjacentVertex(t,e)
2419 * 13 if vertex w is not discovered and not explored
2420 * 14 label e as tree-edge
2421 * 15 label w as discovered
2424 * 18 else if vertex w is discovered
2425 * 19 label e as back-edge
2427 * 21 // vertex w is explored
2428 * 22 label e as forward- or cross-edge
2429 * 23 label t as explored
2434 * 0x11 - discovered and fall-through edge labelled
2435 * 0x12 - discovered and fall-through and branch edges labelled
2446 #define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L)
2448 static int *insn_stack
; /* stack of insns to process */
2449 static int cur_stack
; /* current stack index */
2450 static int *insn_state
;
2452 /* t, w, e - match pseudo-code above:
2453 * t - index of current instruction
2454 * w - next instruction
2457 static int push_insn(int t
, int w
, int e
, struct bpf_verifier_env
*env
)
2459 if (e
== FALLTHROUGH
&& insn_state
[t
] >= (DISCOVERED
| FALLTHROUGH
))
2462 if (e
== BRANCH
&& insn_state
[t
] >= (DISCOVERED
| BRANCH
))
2465 if (w
< 0 || w
>= env
->prog
->len
) {
2466 verbose("jump out of range from insn %d to %d\n", t
, w
);
2471 /* mark branch target for state pruning */
2472 env
->explored_states
[w
] = STATE_LIST_MARK
;
2474 if (insn_state
[w
] == 0) {
2476 insn_state
[t
] = DISCOVERED
| e
;
2477 insn_state
[w
] = DISCOVERED
;
2478 if (cur_stack
>= env
->prog
->len
)
2480 insn_stack
[cur_stack
++] = w
;
2482 } else if ((insn_state
[w
] & 0xF0) == DISCOVERED
) {
2483 verbose("back-edge from insn %d to %d\n", t
, w
);
2485 } else if (insn_state
[w
] == EXPLORED
) {
2486 /* forward- or cross-edge */
2487 insn_state
[t
] = DISCOVERED
| e
;
2489 verbose("insn state internal bug\n");
2495 /* non-recursive depth-first-search to detect loops in BPF program
2496 * loop == back-edge in directed graph
2498 static int check_cfg(struct bpf_verifier_env
*env
)
2500 struct bpf_insn
*insns
= env
->prog
->insnsi
;
2501 int insn_cnt
= env
->prog
->len
;
2505 insn_state
= kcalloc(insn_cnt
, sizeof(int), GFP_KERNEL
);
2509 insn_stack
= kcalloc(insn_cnt
, sizeof(int), GFP_KERNEL
);
2515 insn_state
[0] = DISCOVERED
; /* mark 1st insn as discovered */
2516 insn_stack
[0] = 0; /* 0 is the first instruction */
2522 t
= insn_stack
[cur_stack
- 1];
2524 if (BPF_CLASS(insns
[t
].code
) == BPF_JMP
) {
2525 u8 opcode
= BPF_OP(insns
[t
].code
);
2527 if (opcode
== BPF_EXIT
) {
2529 } else if (opcode
== BPF_CALL
) {
2530 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
);
2535 if (t
+ 1 < insn_cnt
)
2536 env
->explored_states
[t
+ 1] = STATE_LIST_MARK
;
2537 } else if (opcode
== BPF_JA
) {
2538 if (BPF_SRC(insns
[t
].code
) != BPF_K
) {
2542 /* unconditional jump with single edge */
2543 ret
= push_insn(t
, t
+ insns
[t
].off
+ 1,
2549 /* tell verifier to check for equivalent states
2550 * after every call and jump
2552 if (t
+ 1 < insn_cnt
)
2553 env
->explored_states
[t
+ 1] = STATE_LIST_MARK
;
2555 /* conditional jump with two edges */
2556 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
);
2562 ret
= push_insn(t
, t
+ insns
[t
].off
+ 1, BRANCH
, env
);
2569 /* all other non-branch instructions with single
2572 ret
= push_insn(t
, t
+ 1, FALLTHROUGH
, env
);
2580 insn_state
[t
] = EXPLORED
;
2581 if (cur_stack
-- <= 0) {
2582 verbose("pop stack internal bug\n");
2589 for (i
= 0; i
< insn_cnt
; i
++) {
2590 if (insn_state
[i
] != EXPLORED
) {
2591 verbose("unreachable insn %d\n", i
);
2596 ret
= 0; /* cfg looks good */
2604 /* the following conditions reduce the number of explored insns
2605 * from ~140k to ~80k for ultra large programs that use a lot of ptr_to_packet
2607 static bool compare_ptrs_to_packet(struct bpf_reg_state
*old
,
2608 struct bpf_reg_state
*cur
)
2610 if (old
->id
!= cur
->id
)
2613 /* old ptr_to_packet is more conservative, since it allows smaller
2615 * old(off=0,r=10) is equal to cur(off=0,r=20), because
2616 * old(off=0,r=10) means that with range=10 the verifier proceeded
2617 * further and found no issues with the program. Now we're in the same
2618 * spot with cur(off=0,r=20), so we're safe too, since anything further
2619 * will only be looking at most 10 bytes after this pointer.
2621 if (old
->off
== cur
->off
&& old
->range
< cur
->range
)
2624 /* old(off=20,r=10) is equal to cur(off=22,re=22 or 5 or 0)
2625 * since both cannot be used for packet access and safe(old)
2626 * pointer has smaller off that could be used for further
2627 * 'if (ptr > data_end)' check
2629 * old(off=20,r=10) and cur(off=22,r=22) and cur(off=22,r=0) mean
2630 * that we cannot access the packet.
2631 * The safe range is:
2632 * [ptr, ptr + range - off)
2633 * so whenever off >=range, it means no safe bytes from this pointer.
2634 * When comparing old->off <= cur->off, it means that older code
2635 * went with smaller offset and that offset was later
2636 * used to figure out the safe range after 'if (ptr > data_end)' check
2637 * Say, 'old' state was explored like:
2638 * ... R3(off=0, r=0)
2640 * ... now R4(off=20,r=0) <-- here
2641 * if (R4 > data_end)
2642 * ... R4(off=20,r=20), R3(off=0,r=20) and R3 can be used to access.
2643 * ... the code further went all the way to bpf_exit.
2644 * Now the 'cur' state at the mark 'here' has R4(off=30,r=0).
2645 * old_R4(off=20,r=0) equal to cur_R4(off=30,r=0), since if the verifier
2646 * goes further, such cur_R4 will give larger safe packet range after
2647 * 'if (R4 > data_end)' and all further insn were already good with r=20,
2648 * so they will be good with r=30 and we can prune the search.
2650 if (old
->off
<= cur
->off
&&
2651 old
->off
>= old
->range
&& cur
->off
>= cur
->range
)
2657 /* compare two verifier states
2659 * all states stored in state_list are known to be valid, since
2660 * verifier reached 'bpf_exit' instruction through them
2662 * this function is called when verifier exploring different branches of
2663 * execution popped from the state stack. If it sees an old state that has
2664 * more strict register state and more strict stack state then this execution
2665 * branch doesn't need to be explored further, since verifier already
2666 * concluded that more strict state leads to valid finish.
2668 * Therefore two states are equivalent if register state is more conservative
2669 * and explored stack state is more conservative than the current one.
2672 * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
2673 * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
2675 * In other words if current stack state (one being explored) has more
2676 * valid slots than old one that already passed validation, it means
2677 * the verifier can stop exploring and conclude that current state is valid too
2679 * Similarly with registers. If explored state has register type as invalid
2680 * whereas register type in current state is meaningful, it means that
2681 * the current state will reach 'bpf_exit' instruction safely
2683 static bool states_equal(struct bpf_verifier_env
*env
,
2684 struct bpf_verifier_state
*old
,
2685 struct bpf_verifier_state
*cur
)
2687 bool varlen_map_access
= env
->varlen_map_value_access
;
2688 struct bpf_reg_state
*rold
, *rcur
;
2691 for (i
= 0; i
< MAX_BPF_REG
; i
++) {
2692 rold
= &old
->regs
[i
];
2693 rcur
= &cur
->regs
[i
];
2695 if (memcmp(rold
, rcur
, sizeof(*rold
)) == 0)
2698 /* If the ranges were not the same, but everything else was and
2699 * we didn't do a variable access into a map then we are a-ok.
2701 if (!varlen_map_access
&&
2702 memcmp(rold
, rcur
, offsetofend(struct bpf_reg_state
, id
)) == 0)
2705 /* If we didn't map access then again we don't care about the
2706 * mismatched range values and it's ok if our old type was
2707 * UNKNOWN and we didn't go to a NOT_INIT'ed reg.
2709 if (rold
->type
== NOT_INIT
||
2710 (!varlen_map_access
&& rold
->type
== UNKNOWN_VALUE
&&
2711 rcur
->type
!= NOT_INIT
))
2714 if (rold
->type
== PTR_TO_PACKET
&& rcur
->type
== PTR_TO_PACKET
&&
2715 compare_ptrs_to_packet(rold
, rcur
))
2721 for (i
= 0; i
< MAX_BPF_STACK
; i
++) {
2722 if (old
->stack_slot_type
[i
] == STACK_INVALID
)
2724 if (old
->stack_slot_type
[i
] != cur
->stack_slot_type
[i
])
2725 /* Ex: old explored (safe) state has STACK_SPILL in
2726 * this stack slot, but current has has STACK_MISC ->
2727 * this verifier states are not equivalent,
2728 * return false to continue verification of this path
2731 if (i
% BPF_REG_SIZE
)
2733 if (memcmp(&old
->spilled_regs
[i
/ BPF_REG_SIZE
],
2734 &cur
->spilled_regs
[i
/ BPF_REG_SIZE
],
2735 sizeof(old
->spilled_regs
[0])))
2736 /* when explored and current stack slot types are
2737 * the same, check that stored pointers types
2738 * are the same as well.
2739 * Ex: explored safe path could have stored
2740 * (bpf_reg_state) {.type = PTR_TO_STACK, .imm = -8}
2741 * but current path has stored:
2742 * (bpf_reg_state) {.type = PTR_TO_STACK, .imm = -16}
2743 * such verifier states are not equivalent.
2744 * return false to continue verification of this path
2753 static int is_state_visited(struct bpf_verifier_env
*env
, int insn_idx
)
2755 struct bpf_verifier_state_list
*new_sl
;
2756 struct bpf_verifier_state_list
*sl
;
2758 sl
= env
->explored_states
[insn_idx
];
2760 /* this 'insn_idx' instruction wasn't marked, so we will not
2761 * be doing state search here
2765 while (sl
!= STATE_LIST_MARK
) {
2766 if (states_equal(env
, &sl
->state
, &env
->cur_state
))
2767 /* reached equivalent register/stack state,
2774 /* there were no equivalent states, remember current one.
2775 * technically the current state is not proven to be safe yet,
2776 * but it will either reach bpf_exit (which means it's safe) or
2777 * it will be rejected. Since there are no loops, we won't be
2778 * seeing this 'insn_idx' instruction again on the way to bpf_exit
2780 new_sl
= kmalloc(sizeof(struct bpf_verifier_state_list
), GFP_USER
);
2784 /* add new state to the head of linked list */
2785 memcpy(&new_sl
->state
, &env
->cur_state
, sizeof(env
->cur_state
));
2786 new_sl
->next
= env
->explored_states
[insn_idx
];
2787 env
->explored_states
[insn_idx
] = new_sl
;
2791 static int ext_analyzer_insn_hook(struct bpf_verifier_env
*env
,
2792 int insn_idx
, int prev_insn_idx
)
2794 if (!env
->analyzer_ops
|| !env
->analyzer_ops
->insn_hook
)
2797 return env
->analyzer_ops
->insn_hook(env
, insn_idx
, prev_insn_idx
);
2800 static int do_check(struct bpf_verifier_env
*env
)
2802 struct bpf_verifier_state
*state
= &env
->cur_state
;
2803 struct bpf_insn
*insns
= env
->prog
->insnsi
;
2804 struct bpf_reg_state
*regs
= state
->regs
;
2805 int insn_cnt
= env
->prog
->len
;
2806 int insn_idx
, prev_insn_idx
= 0;
2807 int insn_processed
= 0;
2808 bool do_print_state
= false;
2810 init_reg_state(regs
);
2812 env
->varlen_map_value_access
= false;
2814 struct bpf_insn
*insn
;
2818 if (insn_idx
>= insn_cnt
) {
2819 verbose("invalid insn idx %d insn_cnt %d\n",
2820 insn_idx
, insn_cnt
);
2824 insn
= &insns
[insn_idx
];
2825 class = BPF_CLASS(insn
->code
);
2827 if (++insn_processed
> BPF_COMPLEXITY_LIMIT_INSNS
) {
2828 verbose("BPF program is too large. Processed %d insn\n",
2833 err
= is_state_visited(env
, insn_idx
);
2837 /* found equivalent state, can prune the search */
2840 verbose("\nfrom %d to %d: safe\n",
2841 prev_insn_idx
, insn_idx
);
2843 verbose("%d: safe\n", insn_idx
);
2845 goto process_bpf_exit
;
2848 if (log_level
&& do_print_state
) {
2849 verbose("\nfrom %d to %d:", prev_insn_idx
, insn_idx
);
2850 print_verifier_state(&env
->cur_state
);
2851 do_print_state
= false;
2855 verbose("%d: ", insn_idx
);
2856 print_bpf_insn(insn
);
2859 err
= ext_analyzer_insn_hook(env
, insn_idx
, prev_insn_idx
);
2863 if (class == BPF_ALU
|| class == BPF_ALU64
) {
2864 err
= check_alu_op(env
, insn
);
2868 } else if (class == BPF_LDX
) {
2869 enum bpf_reg_type
*prev_src_type
, src_reg_type
;
2871 /* check for reserved fields is already done */
2873 /* check src operand */
2874 err
= check_reg_arg(regs
, insn
->src_reg
, SRC_OP
);
2878 err
= check_reg_arg(regs
, insn
->dst_reg
, DST_OP_NO_MARK
);
2882 src_reg_type
= regs
[insn
->src_reg
].type
;
2884 /* check that memory (src_reg + off) is readable,
2885 * the state of dst_reg will be updated by this func
2887 err
= check_mem_access(env
, insn
->src_reg
, insn
->off
,
2888 BPF_SIZE(insn
->code
), BPF_READ
,
2893 if (BPF_SIZE(insn
->code
) != BPF_W
&&
2894 BPF_SIZE(insn
->code
) != BPF_DW
) {
2899 prev_src_type
= &env
->insn_aux_data
[insn_idx
].ptr_type
;
2901 if (*prev_src_type
== NOT_INIT
) {
2903 * dst_reg = *(u32 *)(src_reg + off)
2904 * save type to validate intersecting paths
2906 *prev_src_type
= src_reg_type
;
2908 } else if (src_reg_type
!= *prev_src_type
&&
2909 (src_reg_type
== PTR_TO_CTX
||
2910 *prev_src_type
== PTR_TO_CTX
)) {
2911 /* ABuser program is trying to use the same insn
2912 * dst_reg = *(u32*) (src_reg + off)
2913 * with different pointer types:
2914 * src_reg == ctx in one branch and
2915 * src_reg == stack|map in some other branch.
2918 verbose("same insn cannot be used with different pointers\n");
2922 } else if (class == BPF_STX
) {
2923 enum bpf_reg_type
*prev_dst_type
, dst_reg_type
;
2925 if (BPF_MODE(insn
->code
) == BPF_XADD
) {
2926 err
= check_xadd(env
, insn
);
2933 /* check src1 operand */
2934 err
= check_reg_arg(regs
, insn
->src_reg
, SRC_OP
);
2937 /* check src2 operand */
2938 err
= check_reg_arg(regs
, insn
->dst_reg
, SRC_OP
);
2942 dst_reg_type
= regs
[insn
->dst_reg
].type
;
2944 /* check that memory (dst_reg + off) is writeable */
2945 err
= check_mem_access(env
, insn
->dst_reg
, insn
->off
,
2946 BPF_SIZE(insn
->code
), BPF_WRITE
,
2951 prev_dst_type
= &env
->insn_aux_data
[insn_idx
].ptr_type
;
2953 if (*prev_dst_type
== NOT_INIT
) {
2954 *prev_dst_type
= dst_reg_type
;
2955 } else if (dst_reg_type
!= *prev_dst_type
&&
2956 (dst_reg_type
== PTR_TO_CTX
||
2957 *prev_dst_type
== PTR_TO_CTX
)) {
2958 verbose("same insn cannot be used with different pointers\n");
2962 } else if (class == BPF_ST
) {
2963 if (BPF_MODE(insn
->code
) != BPF_MEM
||
2964 insn
->src_reg
!= BPF_REG_0
) {
2965 verbose("BPF_ST uses reserved fields\n");
2968 /* check src operand */
2969 err
= check_reg_arg(regs
, insn
->dst_reg
, SRC_OP
);
2973 /* check that memory (dst_reg + off) is writeable */
2974 err
= check_mem_access(env
, insn
->dst_reg
, insn
->off
,
2975 BPF_SIZE(insn
->code
), BPF_WRITE
,
2980 } else if (class == BPF_JMP
) {
2981 u8 opcode
= BPF_OP(insn
->code
);
2983 if (opcode
== BPF_CALL
) {
2984 if (BPF_SRC(insn
->code
) != BPF_K
||
2986 insn
->src_reg
!= BPF_REG_0
||
2987 insn
->dst_reg
!= BPF_REG_0
) {
2988 verbose("BPF_CALL uses reserved fields\n");
2992 err
= check_call(env
, insn
->imm
, insn_idx
);
2996 } else if (opcode
== BPF_JA
) {
2997 if (BPF_SRC(insn
->code
) != BPF_K
||
2999 insn
->src_reg
!= BPF_REG_0
||
3000 insn
->dst_reg
!= BPF_REG_0
) {
3001 verbose("BPF_JA uses reserved fields\n");
3005 insn_idx
+= insn
->off
+ 1;
3008 } else if (opcode
== BPF_EXIT
) {
3009 if (BPF_SRC(insn
->code
) != BPF_K
||
3011 insn
->src_reg
!= BPF_REG_0
||
3012 insn
->dst_reg
!= BPF_REG_0
) {
3013 verbose("BPF_EXIT uses reserved fields\n");
3017 /* eBPF calling convetion is such that R0 is used
3018 * to return the value from eBPF program.
3019 * Make sure that it's readable at this time
3020 * of bpf_exit, which means that program wrote
3021 * something into it earlier
3023 err
= check_reg_arg(regs
, BPF_REG_0
, SRC_OP
);
3027 if (is_pointer_value(env
, BPF_REG_0
)) {
3028 verbose("R0 leaks addr as return value\n");
3033 insn_idx
= pop_stack(env
, &prev_insn_idx
);
3037 do_print_state
= true;
3041 err
= check_cond_jmp_op(env
, insn
, &insn_idx
);
3045 } else if (class == BPF_LD
) {
3046 u8 mode
= BPF_MODE(insn
->code
);
3048 if (mode
== BPF_ABS
|| mode
== BPF_IND
) {
3049 err
= check_ld_abs(env
, insn
);
3053 } else if (mode
== BPF_IMM
) {
3054 err
= check_ld_imm(env
, insn
);
3060 verbose("invalid BPF_LD mode\n");
3063 reset_reg_range_values(regs
, insn
->dst_reg
);
3065 verbose("unknown insn class %d\n", class);
3072 verbose("processed %d insns\n", insn_processed
);
3076 static int check_map_prealloc(struct bpf_map
*map
)
3078 return (map
->map_type
!= BPF_MAP_TYPE_HASH
&&
3079 map
->map_type
!= BPF_MAP_TYPE_PERCPU_HASH
&&
3080 map
->map_type
!= BPF_MAP_TYPE_HASH_OF_MAPS
) ||
3081 !(map
->map_flags
& BPF_F_NO_PREALLOC
);
3084 static int check_map_prog_compatibility(struct bpf_map
*map
,
3085 struct bpf_prog
*prog
)
3088 /* Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use
3089 * preallocated hash maps, since doing memory allocation
3090 * in overflow_handler can crash depending on where nmi got
3093 if (prog
->type
== BPF_PROG_TYPE_PERF_EVENT
) {
3094 if (!check_map_prealloc(map
)) {
3095 verbose("perf_event programs can only use preallocated hash map\n");
3098 if (map
->inner_map_meta
&&
3099 !check_map_prealloc(map
->inner_map_meta
)) {
3100 verbose("perf_event programs can only use preallocated inner hash map\n");
3107 /* look for pseudo eBPF instructions that access map FDs and
3108 * replace them with actual map pointers
3110 static int replace_map_fd_with_map_ptr(struct bpf_verifier_env
*env
)
3112 struct bpf_insn
*insn
= env
->prog
->insnsi
;
3113 int insn_cnt
= env
->prog
->len
;
3116 err
= bpf_prog_calc_tag(env
->prog
);
3120 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
3121 if (BPF_CLASS(insn
->code
) == BPF_LDX
&&
3122 (BPF_MODE(insn
->code
) != BPF_MEM
|| insn
->imm
!= 0)) {
3123 verbose("BPF_LDX uses reserved fields\n");
3127 if (BPF_CLASS(insn
->code
) == BPF_STX
&&
3128 ((BPF_MODE(insn
->code
) != BPF_MEM
&&
3129 BPF_MODE(insn
->code
) != BPF_XADD
) || insn
->imm
!= 0)) {
3130 verbose("BPF_STX uses reserved fields\n");
3134 if (insn
[0].code
== (BPF_LD
| BPF_IMM
| BPF_DW
)) {
3135 struct bpf_map
*map
;
3138 if (i
== insn_cnt
- 1 || insn
[1].code
!= 0 ||
3139 insn
[1].dst_reg
!= 0 || insn
[1].src_reg
!= 0 ||
3141 verbose("invalid bpf_ld_imm64 insn\n");
3145 if (insn
->src_reg
== 0)
3146 /* valid generic load 64-bit imm */
3149 if (insn
->src_reg
!= BPF_PSEUDO_MAP_FD
) {
3150 verbose("unrecognized bpf_ld_imm64 insn\n");
3154 f
= fdget(insn
->imm
);
3155 map
= __bpf_map_get(f
);
3157 verbose("fd %d is not pointing to valid bpf_map\n",
3159 return PTR_ERR(map
);
3162 err
= check_map_prog_compatibility(map
, env
->prog
);
3168 /* store map pointer inside BPF_LD_IMM64 instruction */
3169 insn
[0].imm
= (u32
) (unsigned long) map
;
3170 insn
[1].imm
= ((u64
) (unsigned long) map
) >> 32;
3172 /* check whether we recorded this map already */
3173 for (j
= 0; j
< env
->used_map_cnt
; j
++)
3174 if (env
->used_maps
[j
] == map
) {
3179 if (env
->used_map_cnt
>= MAX_USED_MAPS
) {
3184 /* hold the map. If the program is rejected by verifier,
3185 * the map will be released by release_maps() or it
3186 * will be used by the valid program until it's unloaded
3187 * and all maps are released in free_bpf_prog_info()
3189 map
= bpf_map_inc(map
, false);
3192 return PTR_ERR(map
);
3194 env
->used_maps
[env
->used_map_cnt
++] = map
;
3203 /* now all pseudo BPF_LD_IMM64 instructions load valid
3204 * 'struct bpf_map *' into a register instead of user map_fd.
3205 * These pointers will be used later by verifier to validate map access.
3210 /* drop refcnt of maps used by the rejected program */
3211 static void release_maps(struct bpf_verifier_env
*env
)
3215 for (i
= 0; i
< env
->used_map_cnt
; i
++)
3216 bpf_map_put(env
->used_maps
[i
]);
3219 /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
3220 static void convert_pseudo_ld_imm64(struct bpf_verifier_env
*env
)
3222 struct bpf_insn
*insn
= env
->prog
->insnsi
;
3223 int insn_cnt
= env
->prog
->len
;
3226 for (i
= 0; i
< insn_cnt
; i
++, insn
++)
3227 if (insn
->code
== (BPF_LD
| BPF_IMM
| BPF_DW
))
3231 /* single env->prog->insni[off] instruction was replaced with the range
3232 * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying
3233 * [0, off) and [off, end) to new locations, so the patched range stays zero
3235 static int adjust_insn_aux_data(struct bpf_verifier_env
*env
, u32 prog_len
,
3238 struct bpf_insn_aux_data
*new_data
, *old_data
= env
->insn_aux_data
;
3242 new_data
= vzalloc(sizeof(struct bpf_insn_aux_data
) * prog_len
);
3245 memcpy(new_data
, old_data
, sizeof(struct bpf_insn_aux_data
) * off
);
3246 memcpy(new_data
+ off
+ cnt
- 1, old_data
+ off
,
3247 sizeof(struct bpf_insn_aux_data
) * (prog_len
- off
- cnt
+ 1));
3248 env
->insn_aux_data
= new_data
;
3253 static struct bpf_prog
*bpf_patch_insn_data(struct bpf_verifier_env
*env
, u32 off
,
3254 const struct bpf_insn
*patch
, u32 len
)
3256 struct bpf_prog
*new_prog
;
3258 new_prog
= bpf_patch_insn_single(env
->prog
, off
, patch
, len
);
3261 if (adjust_insn_aux_data(env
, new_prog
->len
, off
, len
))
3266 /* convert load instructions that access fields of 'struct __sk_buff'
3267 * into sequence of instructions that access fields of 'struct sk_buff'
3269 static int convert_ctx_accesses(struct bpf_verifier_env
*env
)
3271 const struct bpf_verifier_ops
*ops
= env
->prog
->aux
->ops
;
3272 const int insn_cnt
= env
->prog
->len
;
3273 struct bpf_insn insn_buf
[16], *insn
;
3274 struct bpf_prog
*new_prog
;
3275 enum bpf_access_type type
;
3276 int i
, cnt
, delta
= 0;
3278 if (ops
->gen_prologue
) {
3279 cnt
= ops
->gen_prologue(insn_buf
, env
->seen_direct_write
,
3281 if (cnt
>= ARRAY_SIZE(insn_buf
)) {
3282 verbose("bpf verifier is misconfigured\n");
3285 new_prog
= bpf_patch_insn_data(env
, 0, insn_buf
, cnt
);
3289 env
->prog
= new_prog
;
3294 if (!ops
->convert_ctx_access
)
3297 insn
= env
->prog
->insnsi
+ delta
;
3299 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
3300 if (insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_B
) ||
3301 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_H
) ||
3302 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_W
) ||
3303 insn
->code
== (BPF_LDX
| BPF_MEM
| BPF_DW
))
3305 else if (insn
->code
== (BPF_STX
| BPF_MEM
| BPF_B
) ||
3306 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_H
) ||
3307 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_W
) ||
3308 insn
->code
== (BPF_STX
| BPF_MEM
| BPF_DW
))
3313 if (env
->insn_aux_data
[i
+ delta
].ptr_type
!= PTR_TO_CTX
)
3316 cnt
= ops
->convert_ctx_access(type
, insn
, insn_buf
, env
->prog
);
3317 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
)) {
3318 verbose("bpf verifier is misconfigured\n");
3322 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
, cnt
);
3328 /* keep walking new program and skip insns we just inserted */
3329 env
->prog
= new_prog
;
3330 insn
= new_prog
->insnsi
+ i
+ delta
;
3336 /* fixup insn->imm field of bpf_call instructions
3337 * and inline eligible helpers as explicit sequence of BPF instructions
3339 * this function is called after eBPF program passed verification
3341 static int fixup_bpf_calls(struct bpf_verifier_env
*env
)
3343 struct bpf_prog
*prog
= env
->prog
;
3344 struct bpf_insn
*insn
= prog
->insnsi
;
3345 const struct bpf_func_proto
*fn
;
3346 const int insn_cnt
= prog
->len
;
3347 struct bpf_insn insn_buf
[16];
3348 struct bpf_prog
*new_prog
;
3349 struct bpf_map
*map_ptr
;
3350 int i
, cnt
, delta
= 0;
3352 for (i
= 0; i
< insn_cnt
; i
++, insn
++) {
3353 if (insn
->code
!= (BPF_JMP
| BPF_CALL
))
3356 if (insn
->imm
== BPF_FUNC_get_route_realm
)
3357 prog
->dst_needed
= 1;
3358 if (insn
->imm
== BPF_FUNC_get_prandom_u32
)
3359 bpf_user_rnd_init_once();
3360 if (insn
->imm
== BPF_FUNC_tail_call
) {
3361 /* If we tail call into other programs, we
3362 * cannot make any assumptions since they can
3363 * be replaced dynamically during runtime in
3364 * the program array.
3366 prog
->cb_access
= 1;
3368 /* mark bpf_tail_call as different opcode to avoid
3369 * conditional branch in the interpeter for every normal
3370 * call and to prevent accidental JITing by JIT compiler
3371 * that doesn't support bpf_tail_call yet
3374 insn
->code
|= BPF_X
;
3378 if (ebpf_jit_enabled() && insn
->imm
== BPF_FUNC_map_lookup_elem
) {
3379 map_ptr
= env
->insn_aux_data
[i
+ delta
].map_ptr
;
3380 if (map_ptr
== BPF_MAP_PTR_POISON
||
3381 !map_ptr
->ops
->map_gen_lookup
)
3382 goto patch_call_imm
;
3384 cnt
= map_ptr
->ops
->map_gen_lookup(map_ptr
, insn_buf
);
3385 if (cnt
== 0 || cnt
>= ARRAY_SIZE(insn_buf
)) {
3386 verbose("bpf verifier is misconfigured\n");
3390 new_prog
= bpf_patch_insn_data(env
, i
+ delta
, insn_buf
,
3397 /* keep walking new program and skip insns we just inserted */
3398 env
->prog
= prog
= new_prog
;
3399 insn
= new_prog
->insnsi
+ i
+ delta
;
3404 fn
= prog
->aux
->ops
->get_func_proto(insn
->imm
);
3405 /* all functions that have prototype and verifier allowed
3406 * programs to call them, must be real in-kernel functions
3409 verbose("kernel subsystem misconfigured func %s#%d\n",
3410 func_id_name(insn
->imm
), insn
->imm
);
3413 insn
->imm
= fn
->func
- __bpf_call_base
;
3419 static void free_states(struct bpf_verifier_env
*env
)
3421 struct bpf_verifier_state_list
*sl
, *sln
;
3424 if (!env
->explored_states
)
3427 for (i
= 0; i
< env
->prog
->len
; i
++) {
3428 sl
= env
->explored_states
[i
];
3431 while (sl
!= STATE_LIST_MARK
) {
3438 kfree(env
->explored_states
);
3441 int bpf_check(struct bpf_prog
**prog
, union bpf_attr
*attr
)
3443 char __user
*log_ubuf
= NULL
;
3444 struct bpf_verifier_env
*env
;
3447 /* 'struct bpf_verifier_env' can be global, but since it's not small,
3448 * allocate/free it every time bpf_check() is called
3450 env
= kzalloc(sizeof(struct bpf_verifier_env
), GFP_KERNEL
);
3454 env
->insn_aux_data
= vzalloc(sizeof(struct bpf_insn_aux_data
) *
3457 if (!env
->insn_aux_data
)
3461 /* grab the mutex to protect few globals used by verifier */
3462 mutex_lock(&bpf_verifier_lock
);
3464 if (attr
->log_level
|| attr
->log_buf
|| attr
->log_size
) {
3465 /* user requested verbose verifier output
3466 * and supplied buffer to store the verification trace
3468 log_level
= attr
->log_level
;
3469 log_ubuf
= (char __user
*) (unsigned long) attr
->log_buf
;
3470 log_size
= attr
->log_size
;
3474 /* log_* values have to be sane */
3475 if (log_size
< 128 || log_size
> UINT_MAX
>> 8 ||
3476 log_level
== 0 || log_ubuf
== NULL
)
3480 log_buf
= vmalloc(log_size
);
3487 ret
= replace_map_fd_with_map_ptr(env
);
3489 goto skip_full_check
;
3491 env
->explored_states
= kcalloc(env
->prog
->len
,
3492 sizeof(struct bpf_verifier_state_list
*),
3495 if (!env
->explored_states
)
3496 goto skip_full_check
;
3498 ret
= check_cfg(env
);
3500 goto skip_full_check
;
3502 env
->allow_ptr_leaks
= capable(CAP_SYS_ADMIN
);
3504 ret
= do_check(env
);
3507 while (pop_stack(env
, NULL
) >= 0);
3511 /* program is valid, convert *(u32*)(ctx + off) accesses */
3512 ret
= convert_ctx_accesses(env
);
3515 ret
= fixup_bpf_calls(env
);
3517 if (log_level
&& log_len
>= log_size
- 1) {
3518 BUG_ON(log_len
>= log_size
);
3519 /* verifier log exceeded user supplied buffer */
3521 /* fall through to return what was recorded */
3524 /* copy verifier log back to user space including trailing zero */
3525 if (log_level
&& copy_to_user(log_ubuf
, log_buf
, log_len
+ 1) != 0) {
3530 if (ret
== 0 && env
->used_map_cnt
) {
3531 /* if program passed verifier, update used_maps in bpf_prog_info */
3532 env
->prog
->aux
->used_maps
= kmalloc_array(env
->used_map_cnt
,
3533 sizeof(env
->used_maps
[0]),
3536 if (!env
->prog
->aux
->used_maps
) {
3541 memcpy(env
->prog
->aux
->used_maps
, env
->used_maps
,
3542 sizeof(env
->used_maps
[0]) * env
->used_map_cnt
);
3543 env
->prog
->aux
->used_map_cnt
= env
->used_map_cnt
;
3545 /* program is valid. Convert pseudo bpf_ld_imm64 into generic
3546 * bpf_ld_imm64 instructions
3548 convert_pseudo_ld_imm64(env
);
3554 if (!env
->prog
->aux
->used_maps
)
3555 /* if we didn't copy map pointers into bpf_prog_info, release
3556 * them now. Otherwise free_bpf_prog_info() will release them.
3561 mutex_unlock(&bpf_verifier_lock
);
3562 vfree(env
->insn_aux_data
);
3568 int bpf_analyzer(struct bpf_prog
*prog
, const struct bpf_ext_analyzer_ops
*ops
,
3571 struct bpf_verifier_env
*env
;
3574 env
= kzalloc(sizeof(struct bpf_verifier_env
), GFP_KERNEL
);
3578 env
->insn_aux_data
= vzalloc(sizeof(struct bpf_insn_aux_data
) *
3581 if (!env
->insn_aux_data
)
3584 env
->analyzer_ops
= ops
;
3585 env
->analyzer_priv
= priv
;
3587 /* grab the mutex to protect few globals used by verifier */
3588 mutex_lock(&bpf_verifier_lock
);
3592 env
->explored_states
= kcalloc(env
->prog
->len
,
3593 sizeof(struct bpf_verifier_state_list
*),
3596 if (!env
->explored_states
)
3597 goto skip_full_check
;
3599 ret
= check_cfg(env
);
3601 goto skip_full_check
;
3603 env
->allow_ptr_leaks
= capable(CAP_SYS_ADMIN
);
3605 ret
= do_check(env
);
3608 while (pop_stack(env
, NULL
) >= 0);
3611 mutex_unlock(&bpf_verifier_lock
);
3612 vfree(env
->insn_aux_data
);
3617 EXPORT_SYMBOL_GPL(bpf_analyzer
);