1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 */
4 #ifndef _LINUX_BPF_VERIFIER_H
5 #define _LINUX_BPF_VERIFIER_H 1
6
7 #include <linux/bpf.h> /* for enum bpf_reg_type */
8 #include <linux/btf.h> /* for struct btf and btf_id() */
9 #include <linux/filter.h> /* for MAX_BPF_STACK */
10 #include <linux/tnum.h>
11
12 /* Maximum variable offset umax_value permitted when resolving memory accesses.
13 * In practice this is far bigger than any realistic pointer offset; this limit
14 * ensures that umax_value + (int)off + (int)size cannot overflow a u64.
15 */
16 #define BPF_MAX_VAR_OFF (1 << 29)
17 /* Maximum variable size permitted for ARG_CONST_SIZE[_OR_ZERO]. This ensures
18 * that converting umax_value to int cannot overflow.
19 */
20 #define BPF_MAX_VAR_SIZ (1 << 29)
21 /* size of tmp_str_buf in bpf_verifier.
22 * we need at least 306 bytes to fit full stack mask representation
23 * (in the "-8,-16,...,-512" form)
24 */
25 #define TMP_STR_BUF_LEN 320
26
27 /* Liveness marks, used for registers and spilled-regs (in stack slots).
28 * Read marks propagate upwards until they find a write mark; they record that
29 * "one of this state's descendants read this reg" (and therefore the reg is
30 * relevant for states_equal() checks).
31 * Write marks collect downwards and do not propagate; they record that "the
32 * straight-line code that reached this state (from its parent) wrote this reg"
33 * (and therefore that reads propagated from this state or its descendants
34 * should not propagate to its parent).
35 * A state with a write mark can receive read marks; it just won't propagate
36 * them to its parent, since the write mark is a property, not of the state,
37 * but of the link between it and its parent. See mark_reg_read() and
38 * mark_stack_slot_read() in kernel/bpf/verifier.c.
39 */
40 enum bpf_reg_liveness {
41 REG_LIVE_NONE = 0, /* reg hasn't been read or written this branch */
42 REG_LIVE_READ32 = 0x1, /* reg was read, so we're sensitive to initial value */
43 REG_LIVE_READ64 = 0x2, /* likewise, but full 64-bit content matters */
44 REG_LIVE_READ = REG_LIVE_READ32 | REG_LIVE_READ64,
45 REG_LIVE_WRITTEN = 0x4, /* reg was written first, screening off later reads */
46 REG_LIVE_DONE = 0x8, /* liveness won't be updating this register anymore */
47 };
48
49 /* For every reg representing a map value or allocated object pointer,
50 * we consider the tuple of (ptr, id) for them to be unique in verifier
51 * context and conside them to not alias each other for the purposes of
52 * tracking lock state.
53 */
54 struct bpf_active_lock {
55 /* This can either be reg->map_ptr or reg->btf. If ptr is NULL,
56 * there's no active lock held, and other fields have no
57 * meaning. If non-NULL, it indicates that a lock is held and
58 * id member has the reg->id of the register which can be >= 0.
59 */
60 void *ptr;
61 /* This will be reg->id */
62 u32 id;
63 };
64
65 #define ITER_PREFIX "bpf_iter_"
66
67 enum bpf_iter_state {
68 BPF_ITER_STATE_INVALID, /* for non-first slot */
69 BPF_ITER_STATE_ACTIVE,
70 BPF_ITER_STATE_DRAINED,
71 };
72
73 struct bpf_reg_state {
74 /* Ordering of fields matters. See states_equal() */
75 enum bpf_reg_type type;
76 /* Fixed part of pointer offset, pointer types only */
77 s32 off;
78 union {
79 /* valid when type == PTR_TO_PACKET */
80 int range;
81
82 /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE |
83 * PTR_TO_MAP_VALUE_OR_NULL
84 */
85 struct {
86 struct bpf_map *map_ptr;
87 /* To distinguish map lookups from outer map
88 * the map_uid is non-zero for registers
89 * pointing to inner maps.
90 */
91 u32 map_uid;
92 };
93
94 /* for PTR_TO_BTF_ID */
95 struct {
96 struct btf *btf;
97 u32 btf_id;
98 };
99
100 struct { /* for PTR_TO_MEM | PTR_TO_MEM_OR_NULL */
101 u32 mem_size;
102 u32 dynptr_id; /* for dynptr slices */
103 };
104
105 /* For dynptr stack slots */
106 struct {
107 enum bpf_dynptr_type type;
108 /* A dynptr is 16 bytes so it takes up 2 stack slots.
109 * We need to track which slot is the first slot
110 * to protect against cases where the user may try to
111 * pass in an address starting at the second slot of the
112 * dynptr.
113 */
114 bool first_slot;
115 } dynptr;
116
117 /* For bpf_iter stack slots */
118 struct {
119 /* BTF container and BTF type ID describing
120 * struct bpf_iter_<type> of an iterator state
121 */
122 struct btf *btf;
123 u32 btf_id;
124 /* packing following two fields to fit iter state into 16 bytes */
125 enum bpf_iter_state state:2;
126 int depth:30;
127 } iter;
128
129 /* Max size from any of the above. */
130 struct {
131 unsigned long raw1;
132 unsigned long raw2;
133 } raw;
134
135 u32 subprogno; /* for PTR_TO_FUNC */
136 };
137 /* For scalar types (SCALAR_VALUE), this represents our knowledge of
138 * the actual value.
139 * For pointer types, this represents the variable part of the offset
140 * from the pointed-to object, and is shared with all bpf_reg_states
141 * with the same id as us.
142 */
143 struct tnum var_off;
144 /* Used to determine if any memory access using this register will
145 * result in a bad access.
146 * These refer to the same value as var_off, not necessarily the actual
147 * contents of the register.
148 */
149 s64 smin_value; /* minimum possible (s64)value */
150 s64 smax_value; /* maximum possible (s64)value */
151 u64 umin_value; /* minimum possible (u64)value */
152 u64 umax_value; /* maximum possible (u64)value */
153 s32 s32_min_value; /* minimum possible (s32)value */
154 s32 s32_max_value; /* maximum possible (s32)value */
155 u32 u32_min_value; /* minimum possible (u32)value */
156 u32 u32_max_value; /* maximum possible (u32)value */
157 /* For PTR_TO_PACKET, used to find other pointers with the same variable
158 * offset, so they can share range knowledge.
159 * For PTR_TO_MAP_VALUE_OR_NULL this is used to share which map value we
160 * came from, when one is tested for != NULL.
161 * For PTR_TO_MEM_OR_NULL this is used to identify memory allocation
162 * for the purpose of tracking that it's freed.
163 * For PTR_TO_SOCKET this is used to share which pointers retain the
164 * same reference to the socket, to determine proper reference freeing.
165 * For stack slots that are dynptrs, this is used to track references to
166 * the dynptr to determine proper reference freeing.
167 * Similarly to dynptrs, we use ID to track "belonging" of a reference
168 * to a specific instance of bpf_iter.
169 */
170 u32 id;
171 /* PTR_TO_SOCKET and PTR_TO_TCP_SOCK could be a ptr returned
172 * from a pointer-cast helper, bpf_sk_fullsock() and
173 * bpf_tcp_sock().
174 *
175 * Consider the following where "sk" is a reference counted
176 * pointer returned from "sk = bpf_sk_lookup_tcp();":
177 *
178 * 1: sk = bpf_sk_lookup_tcp();
179 * 2: if (!sk) { return 0; }
180 * 3: fullsock = bpf_sk_fullsock(sk);
181 * 4: if (!fullsock) { bpf_sk_release(sk); return 0; }
182 * 5: tp = bpf_tcp_sock(fullsock);
183 * 6: if (!tp) { bpf_sk_release(sk); return 0; }
184 * 7: bpf_sk_release(sk);
185 * 8: snd_cwnd = tp->snd_cwnd; // verifier will complain
186 *
187 * After bpf_sk_release(sk) at line 7, both "fullsock" ptr and
188 * "tp" ptr should be invalidated also. In order to do that,
189 * the reg holding "fullsock" and "sk" need to remember
190 * the original refcounted ptr id (i.e. sk_reg->id) in ref_obj_id
191 * such that the verifier can reset all regs which have
192 * ref_obj_id matching the sk_reg->id.
193 *
194 * sk_reg->ref_obj_id is set to sk_reg->id at line 1.
195 * sk_reg->id will stay as NULL-marking purpose only.
196 * After NULL-marking is done, sk_reg->id can be reset to 0.
197 *
198 * After "fullsock = bpf_sk_fullsock(sk);" at line 3,
199 * fullsock_reg->ref_obj_id is set to sk_reg->ref_obj_id.
200 *
201 * After "tp = bpf_tcp_sock(fullsock);" at line 5,
202 * tp_reg->ref_obj_id is set to fullsock_reg->ref_obj_id
203 * which is the same as sk_reg->ref_obj_id.
204 *
205 * From the verifier perspective, if sk, fullsock and tp
206 * are not NULL, they are the same ptr with different
207 * reg->type. In particular, bpf_sk_release(tp) is also
208 * allowed and has the same effect as bpf_sk_release(sk).
209 */
210 u32 ref_obj_id;
211 /* parentage chain for liveness checking */
212 struct bpf_reg_state *parent;
213 /* Inside the callee two registers can be both PTR_TO_STACK like
214 * R1=fp-8 and R2=fp-8, but one of them points to this function stack
215 * while another to the caller's stack. To differentiate them 'frameno'
216 * is used which is an index in bpf_verifier_state->frame[] array
217 * pointing to bpf_func_state.
218 */
219 u32 frameno;
220 /* Tracks subreg definition. The stored value is the insn_idx of the
221 * writing insn. This is safe because subreg_def is used before any insn
222 * patching which only happens after main verification finished.
223 */
224 s32 subreg_def;
225 enum bpf_reg_liveness live;
226 /* if (!precise && SCALAR_VALUE) min/max/tnum don't affect safety */
227 bool precise;
228 };
229
230 enum bpf_stack_slot_type {
231 STACK_INVALID, /* nothing was stored in this stack slot */
232 STACK_SPILL, /* register spilled into stack */
233 STACK_MISC, /* BPF program wrote some data into this slot */
234 STACK_ZERO, /* BPF program wrote constant zero */
235 /* A dynptr is stored in this stack slot. The type of dynptr
236 * is stored in bpf_stack_state->spilled_ptr.dynptr.type
237 */
238 STACK_DYNPTR,
239 STACK_ITER,
240 };
241
242 #define BPF_REG_SIZE 8 /* size of eBPF register in bytes */
243
244 #define BPF_REGMASK_ARGS ((1 << BPF_REG_1) | (1 << BPF_REG_2) | \
245 (1 << BPF_REG_3) | (1 << BPF_REG_4) | \
246 (1 << BPF_REG_5))
247
248 #define BPF_DYNPTR_SIZE sizeof(struct bpf_dynptr_kern)
249 #define BPF_DYNPTR_NR_SLOTS (BPF_DYNPTR_SIZE / BPF_REG_SIZE)
250
251 struct bpf_stack_state {
252 struct bpf_reg_state spilled_ptr;
253 u8 slot_type[BPF_REG_SIZE];
254 };
255
256 struct bpf_reference_state {
257 /* Track each reference created with a unique id, even if the same
258 * instruction creates the reference multiple times (eg, via CALL).
259 */
260 int id;
261 /* Instruction where the allocation of this reference occurred. This
262 * is used purely to inform the user of a reference leak.
263 */
264 int insn_idx;
265 /* There can be a case like:
266 * main (frame 0)
267 * cb (frame 1)
268 * func (frame 3)
269 * cb (frame 4)
270 * Hence for frame 4, if callback_ref just stored boolean, it would be
271 * impossible to distinguish nested callback refs. Hence store the
272 * frameno and compare that to callback_ref in check_reference_leak when
273 * exiting a callback function.
274 */
275 int callback_ref;
276 };
277
278 /* state of the program:
279 * type of all registers and stack info
280 */
281 struct bpf_func_state {
282 struct bpf_reg_state regs[MAX_BPF_REG];
283 /* index of call instruction that called into this func */
284 int callsite;
285 /* stack frame number of this function state from pov of
286 * enclosing bpf_verifier_state.
287 * 0 = main function, 1 = first callee.
288 */
289 u32 frameno;
290 /* subprog number == index within subprog_info
291 * zero == main subprog
292 */
293 u32 subprogno;
294 /* Every bpf_timer_start will increment async_entry_cnt.
295 * It's used to distinguish:
296 * void foo(void) { for(;;); }
297 * void foo(void) { bpf_timer_set_callback(,foo); }
298 */
299 u32 async_entry_cnt;
300 bool in_callback_fn;
301 struct tnum callback_ret_range;
302 bool in_async_callback_fn;
303
304 /* The following fields should be last. See copy_func_state() */
305 int acquired_refs;
306 struct bpf_reference_state *refs;
307 int allocated_stack;
308 struct bpf_stack_state *stack;
309 };
310
311 struct bpf_idx_pair {
312 u32 prev_idx;
313 u32 idx;
314 };
315
316 #define MAX_CALL_FRAMES 8
317 /* Maximum number of register states that can exist at once */
318 #define BPF_ID_MAP_SIZE ((MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE) * MAX_CALL_FRAMES)
319 struct bpf_verifier_state {
320 /* call stack tracking */
321 struct bpf_func_state *frame[MAX_CALL_FRAMES];
322 struct bpf_verifier_state *parent;
323 /*
324 * 'branches' field is the number of branches left to explore:
325 * 0 - all possible paths from this state reached bpf_exit or
326 * were safely pruned
327 * 1 - at least one path is being explored.
328 * This state hasn't reached bpf_exit
329 * 2 - at least two paths are being explored.
330 * This state is an immediate parent of two children.
331 * One is fallthrough branch with branches==1 and another
332 * state is pushed into stack (to be explored later) also with
333 * branches==1. The parent of this state has branches==1.
334 * The verifier state tree connected via 'parent' pointer looks like:
335 * 1
336 * 1
337 * 2 -> 1 (first 'if' pushed into stack)
338 * 1
339 * 2 -> 1 (second 'if' pushed into stack)
340 * 1
341 * 1
342 * 1 bpf_exit.
343 *
344 * Once do_check() reaches bpf_exit, it calls update_branch_counts()
345 * and the verifier state tree will look:
346 * 1
347 * 1
348 * 2 -> 1 (first 'if' pushed into stack)
349 * 1
350 * 1 -> 1 (second 'if' pushed into stack)
351 * 0
352 * 0
353 * 0 bpf_exit.
354 * After pop_stack() the do_check() will resume at second 'if'.
355 *
356 * If is_state_visited() sees a state with branches > 0 it means
357 * there is a loop. If such state is exactly equal to the current state
358 * it's an infinite loop. Note states_equal() checks for states
359 * equivalency, so two states being 'states_equal' does not mean
360 * infinite loop. The exact comparison is provided by
361 * states_maybe_looping() function. It's a stronger pre-check and
362 * much faster than states_equal().
363 *
364 * This algorithm may not find all possible infinite loops or
365 * loop iteration count may be too high.
366 * In such cases BPF_COMPLEXITY_LIMIT_INSNS limit kicks in.
367 */
368 u32 branches;
369 u32 insn_idx;
370 u32 curframe;
371
372 struct bpf_active_lock active_lock;
373 bool speculative;
374 bool active_rcu_lock;
375
376 /* first and last insn idx of this verifier state */
377 u32 first_insn_idx;
378 u32 last_insn_idx;
379 /* jmp history recorded from first to last.
380 * backtracking is using it to go from last to first.
381 * For most states jmp_history_cnt is [0-3].
382 * For loops can go up to ~40.
383 */
384 struct bpf_idx_pair *jmp_history;
385 u32 jmp_history_cnt;
386 };
387
388 #define bpf_get_spilled_reg(slot, frame) \
389 (((slot < frame->allocated_stack / BPF_REG_SIZE) && \
390 (frame->stack[slot].slot_type[0] == STACK_SPILL)) \
391 ? &frame->stack[slot].spilled_ptr : NULL)
392
393 /* Iterate over 'frame', setting 'reg' to either NULL or a spilled register. */
394 #define bpf_for_each_spilled_reg(iter, frame, reg) \
395 for (iter = 0, reg = bpf_get_spilled_reg(iter, frame); \
396 iter < frame->allocated_stack / BPF_REG_SIZE; \
397 iter++, reg = bpf_get_spilled_reg(iter, frame))
398
399 /* Invoke __expr over regsiters in __vst, setting __state and __reg */
400 #define bpf_for_each_reg_in_vstate(__vst, __state, __reg, __expr) \
401 ({ \
402 struct bpf_verifier_state *___vstate = __vst; \
403 int ___i, ___j; \
404 for (___i = 0; ___i <= ___vstate->curframe; ___i++) { \
405 struct bpf_reg_state *___regs; \
406 __state = ___vstate->frame[___i]; \
407 ___regs = __state->regs; \
408 for (___j = 0; ___j < MAX_BPF_REG; ___j++) { \
409 __reg = &___regs[___j]; \
410 (void)(__expr); \
411 } \
412 bpf_for_each_spilled_reg(___j, __state, __reg) { \
413 if (!__reg) \
414 continue; \
415 (void)(__expr); \
416 } \
417 } \
418 })
419
420 /* linked list of verifier states used to prune search */
421 struct bpf_verifier_state_list {
422 struct bpf_verifier_state state;
423 struct bpf_verifier_state_list *next;
424 int miss_cnt, hit_cnt;
425 };
426
427 struct bpf_loop_inline_state {
428 unsigned int initialized:1; /* set to true upon first entry */
429 unsigned int fit_for_inline:1; /* true if callback function is the same
430 * at each call and flags are always zero
431 */
432 u32 callback_subprogno; /* valid when fit_for_inline is true */
433 };
434
435 /* Possible states for alu_state member. */
436 #define BPF_ALU_SANITIZE_SRC (1U << 0)
437 #define BPF_ALU_SANITIZE_DST (1U << 1)
438 #define BPF_ALU_NEG_VALUE (1U << 2)
439 #define BPF_ALU_NON_POINTER (1U << 3)
440 #define BPF_ALU_IMMEDIATE (1U << 4)
441 #define BPF_ALU_SANITIZE (BPF_ALU_SANITIZE_SRC | \
442 BPF_ALU_SANITIZE_DST)
443
444 struct bpf_insn_aux_data {
445 union {
446 enum bpf_reg_type ptr_type; /* pointer type for load/store insns */
447 unsigned long map_ptr_state; /* pointer/poison value for maps */
448 s32 call_imm; /* saved imm field of call insn */
449 u32 alu_limit; /* limit for add/sub register with pointer */
450 struct {
451 u32 map_index; /* index into used_maps[] */
452 u32 map_off; /* offset from value base address */
453 };
454 struct {
455 enum bpf_reg_type reg_type; /* type of pseudo_btf_id */
456 union {
457 struct {
458 struct btf *btf;
459 u32 btf_id; /* btf_id for struct typed var */
460 };
461 u32 mem_size; /* mem_size for non-struct typed var */
462 };
463 } btf_var;
464 /* if instruction is a call to bpf_loop this field tracks
465 * the state of the relevant registers to make decision about inlining
466 */
467 struct bpf_loop_inline_state loop_inline_state;
468 };
469 union {
470 /* remember the size of type passed to bpf_obj_new to rewrite R1 */
471 u64 obj_new_size;
472 /* remember the offset of node field within type to rewrite */
473 u64 insert_off;
474 };
475 struct btf_struct_meta *kptr_struct_meta;
476 u64 map_key_state; /* constant (32 bit) key tracking for maps */
477 int ctx_field_size; /* the ctx field size for load insn, maybe 0 */
478 u32 seen; /* this insn was processed by the verifier at env->pass_cnt */
479 bool sanitize_stack_spill; /* subject to Spectre v4 sanitation */
480 bool zext_dst; /* this insn zero extends dst reg */
481 bool storage_get_func_atomic; /* bpf_*_storage_get() with atomic memory alloc */
482 bool is_iter_next; /* bpf_iter_<type>_next() kfunc call */
483 u8 alu_state; /* used in combination with alu_limit */
484
485 /* below fields are initialized once */
486 unsigned int orig_idx; /* original instruction index */
487 bool jmp_point;
488 bool prune_point;
489 /* ensure we check state equivalence and save state checkpoint and
490 * this instruction, regardless of any heuristics
491 */
492 bool force_checkpoint;
493 };
494
495 #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
496 #define MAX_USED_BTFS 64 /* max number of BTFs accessed by one BPF program */
497
498 #define BPF_VERIFIER_TMP_LOG_SIZE 1024
499
500 struct bpf_verifier_log {
501 /* Logical start and end positions of a "log window" of the verifier log.
502 * start_pos == 0 means we haven't truncated anything.
503 * Once truncation starts to happen, start_pos + len_total == end_pos,
504 * except during log reset situations, in which (end_pos - start_pos)
505 * might get smaller than len_total (see bpf_vlog_reset()).
506 * Generally, (end_pos - start_pos) gives number of useful data in
507 * user log buffer.
508 */
509 u64 start_pos;
510 u64 end_pos;
511 char __user *ubuf;
512 u32 level;
513 u32 len_total;
514 u32 len_max;
515 char kbuf[BPF_VERIFIER_TMP_LOG_SIZE];
516 };
517
518 #define BPF_LOG_LEVEL1 1
519 #define BPF_LOG_LEVEL2 2
520 #define BPF_LOG_STATS 4
521 #define BPF_LOG_FIXED 8
522 #define BPF_LOG_LEVEL (BPF_LOG_LEVEL1 | BPF_LOG_LEVEL2)
523 #define BPF_LOG_MASK (BPF_LOG_LEVEL | BPF_LOG_STATS | BPF_LOG_FIXED)
524 #define BPF_LOG_KERNEL (BPF_LOG_MASK + 1) /* kernel internal flag */
525 #define BPF_LOG_MIN_ALIGNMENT 8U
526 #define BPF_LOG_ALIGNMENT 40U
527
bpf_verifier_log_needed(const struct bpf_verifier_log * log)528 static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
529 {
530 return log && log->level;
531 }
532
533 #define BPF_MAX_SUBPROGS 256
534
535 struct bpf_subprog_info {
536 /* 'start' has to be the first field otherwise find_subprog() won't work */
537 u32 start; /* insn idx of function entry point */
538 u32 linfo_idx; /* The idx to the main_prog->aux->linfo */
539 u16 stack_depth; /* max. stack depth used by this function */
540 bool has_tail_call;
541 bool tail_call_reachable;
542 bool has_ld_abs;
543 bool is_async_cb;
544 };
545
546 struct bpf_verifier_env;
547
548 struct backtrack_state {
549 struct bpf_verifier_env *env;
550 u32 frame;
551 u32 reg_masks[MAX_CALL_FRAMES];
552 u64 stack_masks[MAX_CALL_FRAMES];
553 };
554
555 struct bpf_id_pair {
556 u32 old;
557 u32 cur;
558 };
559
560 struct bpf_idmap {
561 u32 tmp_id_gen;
562 struct bpf_id_pair map[BPF_ID_MAP_SIZE];
563 };
564
565 struct bpf_idset {
566 u32 count;
567 u32 ids[BPF_ID_MAP_SIZE];
568 };
569
570 /* single container for all structs
571 * one verifier_env per bpf_check() call
572 */
573 struct bpf_verifier_env {
574 u32 insn_idx;
575 u32 prev_insn_idx;
576 struct bpf_prog *prog; /* eBPF program being verified */
577 const struct bpf_verifier_ops *ops;
578 struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */
579 int stack_size; /* number of states to be processed */
580 bool strict_alignment; /* perform strict pointer alignment checks */
581 bool test_state_freq; /* test verifier with different pruning frequency */
582 struct bpf_verifier_state *cur_state; /* current verifier state */
583 struct bpf_verifier_state_list **explored_states; /* search pruning optimization */
584 struct bpf_verifier_state_list *free_list;
585 struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */
586 struct btf_mod_pair used_btfs[MAX_USED_BTFS]; /* array of BTF's used by BPF program */
587 u32 used_map_cnt; /* number of used maps */
588 u32 used_btf_cnt; /* number of used BTF objects */
589 u32 id_gen; /* used to generate unique reg IDs */
590 bool explore_alu_limits;
591 bool allow_ptr_leaks;
592 bool allow_uninit_stack;
593 bool bpf_capable;
594 bool bypass_spec_v1;
595 bool bypass_spec_v4;
596 bool seen_direct_write;
597 struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */
598 const struct bpf_line_info *prev_linfo;
599 struct bpf_verifier_log log;
600 struct bpf_subprog_info subprog_info[BPF_MAX_SUBPROGS + 1];
601 union {
602 struct bpf_idmap idmap_scratch;
603 struct bpf_idset idset_scratch;
604 };
605 struct {
606 int *insn_state;
607 int *insn_stack;
608 int cur_stack;
609 } cfg;
610 struct backtrack_state bt;
611 u32 pass_cnt; /* number of times do_check() was called */
612 u32 subprog_cnt;
613 /* number of instructions analyzed by the verifier */
614 u32 prev_insn_processed, insn_processed;
615 /* number of jmps, calls, exits analyzed so far */
616 u32 prev_jmps_processed, jmps_processed;
617 /* total verification time */
618 u64 verification_time;
619 /* maximum number of verifier states kept in 'branching' instructions */
620 u32 max_states_per_insn;
621 /* total number of allocated verifier states */
622 u32 total_states;
623 /* some states are freed during program analysis.
624 * this is peak number of states. this number dominates kernel
625 * memory consumption during verification
626 */
627 u32 peak_states;
628 /* longest register parentage chain walked for liveness marking */
629 u32 longest_mark_read_walk;
630 bpfptr_t fd_array;
631
632 /* bit mask to keep track of whether a register has been accessed
633 * since the last time the function state was printed
634 */
635 u32 scratched_regs;
636 /* Same as scratched_regs but for stack slots */
637 u64 scratched_stack_slots;
638 u64 prev_log_pos, prev_insn_print_pos;
639 /* buffer used to generate temporary string representations,
640 * e.g., in reg_type_str() to generate reg_type string
641 */
642 char tmp_str_buf[TMP_STR_BUF_LEN];
643 };
644
645 __printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log,
646 const char *fmt, va_list args);
647 __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
648 const char *fmt, ...);
649 __printf(2, 3) void bpf_log(struct bpf_verifier_log *log,
650 const char *fmt, ...);
651 int bpf_vlog_init(struct bpf_verifier_log *log, u32 log_level,
652 char __user *log_buf, u32 log_size);
653 void bpf_vlog_reset(struct bpf_verifier_log *log, u64 new_pos);
654 int bpf_vlog_finalize(struct bpf_verifier_log *log, u32 *log_size_actual);
655
cur_func(struct bpf_verifier_env * env)656 static inline struct bpf_func_state *cur_func(struct bpf_verifier_env *env)
657 {
658 struct bpf_verifier_state *cur = env->cur_state;
659
660 return cur->frame[cur->curframe];
661 }
662
cur_regs(struct bpf_verifier_env * env)663 static inline struct bpf_reg_state *cur_regs(struct bpf_verifier_env *env)
664 {
665 return cur_func(env)->regs;
666 }
667
668 int bpf_prog_offload_verifier_prep(struct bpf_prog *prog);
669 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
670 int insn_idx, int prev_insn_idx);
671 int bpf_prog_offload_finalize(struct bpf_verifier_env *env);
672 void
673 bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
674 struct bpf_insn *insn);
675 void
676 bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt);
677
678 int check_ptr_off_reg(struct bpf_verifier_env *env,
679 const struct bpf_reg_state *reg, int regno);
680 int check_func_arg_reg_off(struct bpf_verifier_env *env,
681 const struct bpf_reg_state *reg, int regno,
682 enum bpf_arg_type arg_type);
683 int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
684 u32 regno, u32 mem_size);
685
686 /* this lives here instead of in bpf.h because it needs to dereference tgt_prog */
bpf_trampoline_compute_key(const struct bpf_prog * tgt_prog,struct btf * btf,u32 btf_id)687 static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog,
688 struct btf *btf, u32 btf_id)
689 {
690 if (tgt_prog)
691 return ((u64)tgt_prog->aux->id << 32) | btf_id;
692 else
693 return ((u64)btf_obj_id(btf) << 32) | 0x80000000 | btf_id;
694 }
695
696 /* unpack the IDs from the key as constructed above */
bpf_trampoline_unpack_key(u64 key,u32 * obj_id,u32 * btf_id)697 static inline void bpf_trampoline_unpack_key(u64 key, u32 *obj_id, u32 *btf_id)
698 {
699 if (obj_id)
700 *obj_id = key >> 32;
701 if (btf_id)
702 *btf_id = key & 0x7FFFFFFF;
703 }
704
705 int bpf_check_attach_target(struct bpf_verifier_log *log,
706 const struct bpf_prog *prog,
707 const struct bpf_prog *tgt_prog,
708 u32 btf_id,
709 struct bpf_attach_target_info *tgt_info);
710 void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab);
711
712 int mark_chain_precision(struct bpf_verifier_env *env, int regno);
713
714 #define BPF_BASE_TYPE_MASK GENMASK(BPF_BASE_TYPE_BITS - 1, 0)
715
716 /* extract base type from bpf_{arg, return, reg}_type. */
base_type(u32 type)717 static inline u32 base_type(u32 type)
718 {
719 return type & BPF_BASE_TYPE_MASK;
720 }
721
722 /* extract flags from an extended type. See bpf_type_flag in bpf.h. */
type_flag(u32 type)723 static inline u32 type_flag(u32 type)
724 {
725 return type & ~BPF_BASE_TYPE_MASK;
726 }
727
728 /* only use after check_attach_btf_id() */
resolve_prog_type(const struct bpf_prog * prog)729 static inline enum bpf_prog_type resolve_prog_type(const struct bpf_prog *prog)
730 {
731 return prog->type == BPF_PROG_TYPE_EXT ?
732 prog->aux->dst_prog->type : prog->type;
733 }
734
bpf_prog_check_recur(const struct bpf_prog * prog)735 static inline bool bpf_prog_check_recur(const struct bpf_prog *prog)
736 {
737 switch (resolve_prog_type(prog)) {
738 case BPF_PROG_TYPE_TRACING:
739 return prog->expected_attach_type != BPF_TRACE_ITER;
740 case BPF_PROG_TYPE_STRUCT_OPS:
741 case BPF_PROG_TYPE_LSM:
742 return false;
743 default:
744 return true;
745 }
746 }
747
748 #define BPF_REG_TRUSTED_MODIFIERS (MEM_ALLOC | PTR_TRUSTED | NON_OWN_REF)
749
bpf_type_has_unsafe_modifiers(u32 type)750 static inline bool bpf_type_has_unsafe_modifiers(u32 type)
751 {
752 return type_flag(type) & ~BPF_REG_TRUSTED_MODIFIERS;
753 }
754
755 #endif /* _LINUX_BPF_VERIFIER_H */
756