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[mirror_ubuntu-focal-kernel.git] / kernel / bpf / core.c
1 /*
2 * Linux Socket Filter - Kernel level socket filtering
3 *
4 * Based on the design of the Berkeley Packet Filter. The new
5 * internal format has been designed by PLUMgrid:
6 *
7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
8 *
9 * Authors:
10 *
11 * Jay Schulist <jschlst@samba.org>
12 * Alexei Starovoitov <ast@plumgrid.com>
13 * Daniel Borkmann <dborkman@redhat.com>
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
19 *
20 * Andi Kleen - Fix a few bad bugs and races.
21 * Kris Katterjohn - Added many additional checks in bpf_check_classic()
22 */
23
24 #include <linux/filter.h>
25 #include <linux/skbuff.h>
26 #include <linux/vmalloc.h>
27 #include <linux/random.h>
28 #include <linux/moduleloader.h>
29 #include <linux/bpf.h>
30 #include <linux/frame.h>
31 #include <linux/rbtree_latch.h>
32 #include <linux/kallsyms.h>
33 #include <linux/rcupdate.h>
34
35 #include <asm/unaligned.h>
36
37 /* Registers */
38 #define BPF_R0 regs[BPF_REG_0]
39 #define BPF_R1 regs[BPF_REG_1]
40 #define BPF_R2 regs[BPF_REG_2]
41 #define BPF_R3 regs[BPF_REG_3]
42 #define BPF_R4 regs[BPF_REG_4]
43 #define BPF_R5 regs[BPF_REG_5]
44 #define BPF_R6 regs[BPF_REG_6]
45 #define BPF_R7 regs[BPF_REG_7]
46 #define BPF_R8 regs[BPF_REG_8]
47 #define BPF_R9 regs[BPF_REG_9]
48 #define BPF_R10 regs[BPF_REG_10]
49
50 /* Named registers */
51 #define DST regs[insn->dst_reg]
52 #define SRC regs[insn->src_reg]
53 #define FP regs[BPF_REG_FP]
54 #define ARG1 regs[BPF_REG_ARG1]
55 #define CTX regs[BPF_REG_CTX]
56 #define IMM insn->imm
57
58 /* No hurry in this branch
59 *
60 * Exported for the bpf jit load helper.
61 */
62 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
63 {
64 u8 *ptr = NULL;
65
66 if (k >= SKF_NET_OFF)
67 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
68 else if (k >= SKF_LL_OFF)
69 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
70
71 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
72 return ptr;
73
74 return NULL;
75 }
76
77 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
78 {
79 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
80 struct bpf_prog_aux *aux;
81 struct bpf_prog *fp;
82
83 size = round_up(size, PAGE_SIZE);
84 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
85 if (fp == NULL)
86 return NULL;
87
88 kmemcheck_annotate_bitfield(fp, meta);
89
90 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
91 if (aux == NULL) {
92 vfree(fp);
93 return NULL;
94 }
95
96 fp->pages = size / PAGE_SIZE;
97 fp->aux = aux;
98 fp->aux->prog = fp;
99
100 INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode);
101
102 return fp;
103 }
104 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
105
106 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
107 gfp_t gfp_extra_flags)
108 {
109 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
110 struct bpf_prog *fp;
111 u32 pages, delta;
112 int ret;
113
114 BUG_ON(fp_old == NULL);
115
116 size = round_up(size, PAGE_SIZE);
117 pages = size / PAGE_SIZE;
118 if (pages <= fp_old->pages)
119 return fp_old;
120
121 delta = pages - fp_old->pages;
122 ret = __bpf_prog_charge(fp_old->aux->user, delta);
123 if (ret)
124 return NULL;
125
126 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
127 if (fp == NULL) {
128 __bpf_prog_uncharge(fp_old->aux->user, delta);
129 } else {
130 kmemcheck_annotate_bitfield(fp, meta);
131
132 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
133 fp->pages = pages;
134 fp->aux->prog = fp;
135
136 /* We keep fp->aux from fp_old around in the new
137 * reallocated structure.
138 */
139 fp_old->aux = NULL;
140 __bpf_prog_free(fp_old);
141 }
142
143 return fp;
144 }
145
146 void __bpf_prog_free(struct bpf_prog *fp)
147 {
148 kfree(fp->aux);
149 vfree(fp);
150 }
151
152 int bpf_prog_calc_tag(struct bpf_prog *fp)
153 {
154 const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
155 u32 raw_size = bpf_prog_tag_scratch_size(fp);
156 u32 digest[SHA_DIGEST_WORDS];
157 u32 ws[SHA_WORKSPACE_WORDS];
158 u32 i, bsize, psize, blocks;
159 struct bpf_insn *dst;
160 bool was_ld_map;
161 u8 *raw, *todo;
162 __be32 *result;
163 __be64 *bits;
164
165 raw = vmalloc(raw_size);
166 if (!raw)
167 return -ENOMEM;
168
169 sha_init(digest);
170 memset(ws, 0, sizeof(ws));
171
172 /* We need to take out the map fd for the digest calculation
173 * since they are unstable from user space side.
174 */
175 dst = (void *)raw;
176 for (i = 0, was_ld_map = false; i < fp->len; i++) {
177 dst[i] = fp->insnsi[i];
178 if (!was_ld_map &&
179 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
180 dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
181 was_ld_map = true;
182 dst[i].imm = 0;
183 } else if (was_ld_map &&
184 dst[i].code == 0 &&
185 dst[i].dst_reg == 0 &&
186 dst[i].src_reg == 0 &&
187 dst[i].off == 0) {
188 was_ld_map = false;
189 dst[i].imm = 0;
190 } else {
191 was_ld_map = false;
192 }
193 }
194
195 psize = bpf_prog_insn_size(fp);
196 memset(&raw[psize], 0, raw_size - psize);
197 raw[psize++] = 0x80;
198
199 bsize = round_up(psize, SHA_MESSAGE_BYTES);
200 blocks = bsize / SHA_MESSAGE_BYTES;
201 todo = raw;
202 if (bsize - psize >= sizeof(__be64)) {
203 bits = (__be64 *)(todo + bsize - sizeof(__be64));
204 } else {
205 bits = (__be64 *)(todo + bsize + bits_offset);
206 blocks++;
207 }
208 *bits = cpu_to_be64((psize - 1) << 3);
209
210 while (blocks--) {
211 sha_transform(digest, todo, ws);
212 todo += SHA_MESSAGE_BYTES;
213 }
214
215 result = (__force __be32 *)digest;
216 for (i = 0; i < SHA_DIGEST_WORDS; i++)
217 result[i] = cpu_to_be32(digest[i]);
218 memcpy(fp->tag, result, sizeof(fp->tag));
219
220 vfree(raw);
221 return 0;
222 }
223
224 static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn)
225 {
226 return BPF_CLASS(insn->code) == BPF_JMP &&
227 /* Call and Exit are both special jumps with no
228 * target inside the BPF instruction image.
229 */
230 BPF_OP(insn->code) != BPF_CALL &&
231 BPF_OP(insn->code) != BPF_EXIT;
232 }
233
234 static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
235 {
236 struct bpf_insn *insn = prog->insnsi;
237 u32 i, insn_cnt = prog->len;
238
239 for (i = 0; i < insn_cnt; i++, insn++) {
240 if (!bpf_is_jmp_and_has_target(insn))
241 continue;
242
243 /* Adjust offset of jmps if we cross boundaries. */
244 if (i < pos && i + insn->off + 1 > pos)
245 insn->off += delta;
246 else if (i > pos + delta && i + insn->off + 1 <= pos + delta)
247 insn->off -= delta;
248 }
249 }
250
251 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
252 const struct bpf_insn *patch, u32 len)
253 {
254 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
255 struct bpf_prog *prog_adj;
256
257 /* Since our patchlet doesn't expand the image, we're done. */
258 if (insn_delta == 0) {
259 memcpy(prog->insnsi + off, patch, sizeof(*patch));
260 return prog;
261 }
262
263 insn_adj_cnt = prog->len + insn_delta;
264
265 /* Several new instructions need to be inserted. Make room
266 * for them. Likely, there's no need for a new allocation as
267 * last page could have large enough tailroom.
268 */
269 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
270 GFP_USER);
271 if (!prog_adj)
272 return NULL;
273
274 prog_adj->len = insn_adj_cnt;
275
276 /* Patching happens in 3 steps:
277 *
278 * 1) Move over tail of insnsi from next instruction onwards,
279 * so we can patch the single target insn with one or more
280 * new ones (patching is always from 1 to n insns, n > 0).
281 * 2) Inject new instructions at the target location.
282 * 3) Adjust branch offsets if necessary.
283 */
284 insn_rest = insn_adj_cnt - off - len;
285
286 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
287 sizeof(*patch) * insn_rest);
288 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
289
290 bpf_adj_branches(prog_adj, off, insn_delta);
291
292 return prog_adj;
293 }
294
295 #ifdef CONFIG_BPF_JIT
296 static __always_inline void
297 bpf_get_prog_addr_region(const struct bpf_prog *prog,
298 unsigned long *symbol_start,
299 unsigned long *symbol_end)
300 {
301 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
302 unsigned long addr = (unsigned long)hdr;
303
304 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
305
306 *symbol_start = addr;
307 *symbol_end = addr + hdr->pages * PAGE_SIZE;
308 }
309
310 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
311 {
312 BUILD_BUG_ON(sizeof("bpf_prog_") +
313 sizeof(prog->tag) * 2 + 1 > KSYM_NAME_LEN);
314
315 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
316 sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
317 *sym = 0;
318 }
319
320 static __always_inline unsigned long
321 bpf_get_prog_addr_start(struct latch_tree_node *n)
322 {
323 unsigned long symbol_start, symbol_end;
324 const struct bpf_prog_aux *aux;
325
326 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
327 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
328
329 return symbol_start;
330 }
331
332 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
333 struct latch_tree_node *b)
334 {
335 return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);
336 }
337
338 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
339 {
340 unsigned long val = (unsigned long)key;
341 unsigned long symbol_start, symbol_end;
342 const struct bpf_prog_aux *aux;
343
344 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
345 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
346
347 if (val < symbol_start)
348 return -1;
349 if (val >= symbol_end)
350 return 1;
351
352 return 0;
353 }
354
355 static const struct latch_tree_ops bpf_tree_ops = {
356 .less = bpf_tree_less,
357 .comp = bpf_tree_comp,
358 };
359
360 static DEFINE_SPINLOCK(bpf_lock);
361 static LIST_HEAD(bpf_kallsyms);
362 static struct latch_tree_root bpf_tree __cacheline_aligned;
363
364 int bpf_jit_kallsyms __read_mostly;
365
366 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
367 {
368 WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));
369 list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);
370 latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
371 }
372
373 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
374 {
375 if (list_empty(&aux->ksym_lnode))
376 return;
377
378 latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
379 list_del_rcu(&aux->ksym_lnode);
380 }
381
382 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
383 {
384 return fp->jited && !bpf_prog_was_classic(fp);
385 }
386
387 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
388 {
389 return list_empty(&fp->aux->ksym_lnode) ||
390 fp->aux->ksym_lnode.prev == LIST_POISON2;
391 }
392
393 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
394 {
395 if (!bpf_prog_kallsyms_candidate(fp) ||
396 !capable(CAP_SYS_ADMIN))
397 return;
398
399 spin_lock_bh(&bpf_lock);
400 bpf_prog_ksym_node_add(fp->aux);
401 spin_unlock_bh(&bpf_lock);
402 }
403
404 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
405 {
406 if (!bpf_prog_kallsyms_candidate(fp))
407 return;
408
409 spin_lock_bh(&bpf_lock);
410 bpf_prog_ksym_node_del(fp->aux);
411 spin_unlock_bh(&bpf_lock);
412 }
413
414 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
415 {
416 struct latch_tree_node *n;
417
418 if (!bpf_jit_kallsyms_enabled())
419 return NULL;
420
421 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
422 return n ?
423 container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :
424 NULL;
425 }
426
427 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
428 unsigned long *off, char *sym)
429 {
430 unsigned long symbol_start, symbol_end;
431 struct bpf_prog *prog;
432 char *ret = NULL;
433
434 rcu_read_lock();
435 prog = bpf_prog_kallsyms_find(addr);
436 if (prog) {
437 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
438 bpf_get_prog_name(prog, sym);
439
440 ret = sym;
441 if (size)
442 *size = symbol_end - symbol_start;
443 if (off)
444 *off = addr - symbol_start;
445 }
446 rcu_read_unlock();
447
448 return ret;
449 }
450
451 bool is_bpf_text_address(unsigned long addr)
452 {
453 bool ret;
454
455 rcu_read_lock();
456 ret = bpf_prog_kallsyms_find(addr) != NULL;
457 rcu_read_unlock();
458
459 return ret;
460 }
461
462 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
463 char *sym)
464 {
465 unsigned long symbol_start, symbol_end;
466 struct bpf_prog_aux *aux;
467 unsigned int it = 0;
468 int ret = -ERANGE;
469
470 if (!bpf_jit_kallsyms_enabled())
471 return ret;
472
473 rcu_read_lock();
474 list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {
475 if (it++ != symnum)
476 continue;
477
478 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
479 bpf_get_prog_name(aux->prog, sym);
480
481 *value = symbol_start;
482 *type = BPF_SYM_ELF_TYPE;
483
484 ret = 0;
485 break;
486 }
487 rcu_read_unlock();
488
489 return ret;
490 }
491
492 struct bpf_binary_header *
493 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
494 unsigned int alignment,
495 bpf_jit_fill_hole_t bpf_fill_ill_insns)
496 {
497 struct bpf_binary_header *hdr;
498 unsigned int size, hole, start;
499
500 /* Most of BPF filters are really small, but if some of them
501 * fill a page, allow at least 128 extra bytes to insert a
502 * random section of illegal instructions.
503 */
504 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
505 hdr = module_alloc(size);
506 if (hdr == NULL)
507 return NULL;
508
509 /* Fill space with illegal/arch-dep instructions. */
510 bpf_fill_ill_insns(hdr, size);
511
512 hdr->pages = size / PAGE_SIZE;
513 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
514 PAGE_SIZE - sizeof(*hdr));
515 start = (get_random_int() % hole) & ~(alignment - 1);
516
517 /* Leave a random number of instructions before BPF code. */
518 *image_ptr = &hdr->image[start];
519
520 return hdr;
521 }
522
523 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
524 {
525 module_memfree(hdr);
526 }
527
528 /* This symbol is only overridden by archs that have different
529 * requirements than the usual eBPF JITs, f.e. when they only
530 * implement cBPF JIT, do not set images read-only, etc.
531 */
532 void __weak bpf_jit_free(struct bpf_prog *fp)
533 {
534 if (fp->jited) {
535 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
536
537 bpf_jit_binary_unlock_ro(hdr);
538 bpf_jit_binary_free(hdr);
539
540 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
541 }
542
543 bpf_prog_unlock_free(fp);
544 }
545
546 int bpf_jit_harden __read_mostly;
547
548 static int bpf_jit_blind_insn(const struct bpf_insn *from,
549 const struct bpf_insn *aux,
550 struct bpf_insn *to_buff)
551 {
552 struct bpf_insn *to = to_buff;
553 u32 imm_rnd = get_random_int();
554 s16 off;
555
556 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
557 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
558
559 if (from->imm == 0 &&
560 (from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
561 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
562 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
563 goto out;
564 }
565
566 switch (from->code) {
567 case BPF_ALU | BPF_ADD | BPF_K:
568 case BPF_ALU | BPF_SUB | BPF_K:
569 case BPF_ALU | BPF_AND | BPF_K:
570 case BPF_ALU | BPF_OR | BPF_K:
571 case BPF_ALU | BPF_XOR | BPF_K:
572 case BPF_ALU | BPF_MUL | BPF_K:
573 case BPF_ALU | BPF_MOV | BPF_K:
574 case BPF_ALU | BPF_DIV | BPF_K:
575 case BPF_ALU | BPF_MOD | BPF_K:
576 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
577 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
578 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
579 break;
580
581 case BPF_ALU64 | BPF_ADD | BPF_K:
582 case BPF_ALU64 | BPF_SUB | BPF_K:
583 case BPF_ALU64 | BPF_AND | BPF_K:
584 case BPF_ALU64 | BPF_OR | BPF_K:
585 case BPF_ALU64 | BPF_XOR | BPF_K:
586 case BPF_ALU64 | BPF_MUL | BPF_K:
587 case BPF_ALU64 | BPF_MOV | BPF_K:
588 case BPF_ALU64 | BPF_DIV | BPF_K:
589 case BPF_ALU64 | BPF_MOD | BPF_K:
590 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
591 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
592 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
593 break;
594
595 case BPF_JMP | BPF_JEQ | BPF_K:
596 case BPF_JMP | BPF_JNE | BPF_K:
597 case BPF_JMP | BPF_JGT | BPF_K:
598 case BPF_JMP | BPF_JLT | BPF_K:
599 case BPF_JMP | BPF_JGE | BPF_K:
600 case BPF_JMP | BPF_JLE | BPF_K:
601 case BPF_JMP | BPF_JSGT | BPF_K:
602 case BPF_JMP | BPF_JSLT | BPF_K:
603 case BPF_JMP | BPF_JSGE | BPF_K:
604 case BPF_JMP | BPF_JSLE | BPF_K:
605 case BPF_JMP | BPF_JSET | BPF_K:
606 /* Accommodate for extra offset in case of a backjump. */
607 off = from->off;
608 if (off < 0)
609 off -= 2;
610 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
611 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
612 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
613 break;
614
615 case BPF_LD | BPF_ABS | BPF_W:
616 case BPF_LD | BPF_ABS | BPF_H:
617 case BPF_LD | BPF_ABS | BPF_B:
618 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
619 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
620 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
621 break;
622
623 case BPF_LD | BPF_IND | BPF_W:
624 case BPF_LD | BPF_IND | BPF_H:
625 case BPF_LD | BPF_IND | BPF_B:
626 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
627 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
628 *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
629 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
630 break;
631
632 case BPF_LD | BPF_IMM | BPF_DW:
633 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
634 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
635 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
636 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
637 break;
638 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
639 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
640 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
641 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
642 break;
643
644 case BPF_ST | BPF_MEM | BPF_DW:
645 case BPF_ST | BPF_MEM | BPF_W:
646 case BPF_ST | BPF_MEM | BPF_H:
647 case BPF_ST | BPF_MEM | BPF_B:
648 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
649 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
650 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
651 break;
652 }
653 out:
654 return to - to_buff;
655 }
656
657 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
658 gfp_t gfp_extra_flags)
659 {
660 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
661 struct bpf_prog *fp;
662
663 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
664 if (fp != NULL) {
665 kmemcheck_annotate_bitfield(fp, meta);
666
667 /* aux->prog still points to the fp_other one, so
668 * when promoting the clone to the real program,
669 * this still needs to be adapted.
670 */
671 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
672 }
673
674 return fp;
675 }
676
677 static void bpf_prog_clone_free(struct bpf_prog *fp)
678 {
679 /* aux was stolen by the other clone, so we cannot free
680 * it from this path! It will be freed eventually by the
681 * other program on release.
682 *
683 * At this point, we don't need a deferred release since
684 * clone is guaranteed to not be locked.
685 */
686 fp->aux = NULL;
687 __bpf_prog_free(fp);
688 }
689
690 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
691 {
692 /* We have to repoint aux->prog to self, as we don't
693 * know whether fp here is the clone or the original.
694 */
695 fp->aux->prog = fp;
696 bpf_prog_clone_free(fp_other);
697 }
698
699 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
700 {
701 struct bpf_insn insn_buff[16], aux[2];
702 struct bpf_prog *clone, *tmp;
703 int insn_delta, insn_cnt;
704 struct bpf_insn *insn;
705 int i, rewritten;
706
707 if (!bpf_jit_blinding_enabled())
708 return prog;
709
710 clone = bpf_prog_clone_create(prog, GFP_USER);
711 if (!clone)
712 return ERR_PTR(-ENOMEM);
713
714 insn_cnt = clone->len;
715 insn = clone->insnsi;
716
717 for (i = 0; i < insn_cnt; i++, insn++) {
718 /* We temporarily need to hold the original ld64 insn
719 * so that we can still access the first part in the
720 * second blinding run.
721 */
722 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
723 insn[1].code == 0)
724 memcpy(aux, insn, sizeof(aux));
725
726 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
727 if (!rewritten)
728 continue;
729
730 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
731 if (!tmp) {
732 /* Patching may have repointed aux->prog during
733 * realloc from the original one, so we need to
734 * fix it up here on error.
735 */
736 bpf_jit_prog_release_other(prog, clone);
737 return ERR_PTR(-ENOMEM);
738 }
739
740 clone = tmp;
741 insn_delta = rewritten - 1;
742
743 /* Walk new program and skip insns we just inserted. */
744 insn = clone->insnsi + i + insn_delta;
745 insn_cnt += insn_delta;
746 i += insn_delta;
747 }
748
749 return clone;
750 }
751 #endif /* CONFIG_BPF_JIT */
752
753 /* Base function for offset calculation. Needs to go into .text section,
754 * therefore keeping it non-static as well; will also be used by JITs
755 * anyway later on, so do not let the compiler omit it.
756 */
757 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
758 {
759 return 0;
760 }
761 EXPORT_SYMBOL_GPL(__bpf_call_base);
762
763 /**
764 * __bpf_prog_run - run eBPF program on a given context
765 * @ctx: is the data we are operating on
766 * @insn: is the array of eBPF instructions
767 *
768 * Decode and execute eBPF instructions.
769 */
770 static unsigned int ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn,
771 u64 *stack)
772 {
773 u64 tmp;
774 static const void *jumptable[256] = {
775 [0 ... 255] = &&default_label,
776 /* Now overwrite non-defaults ... */
777 /* 32 bit ALU operations */
778 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
779 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
780 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
781 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
782 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
783 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
784 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
785 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
786 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
787 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
788 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
789 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
790 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
791 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
792 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
793 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
794 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
795 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
796 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
797 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
798 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
799 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
800 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
801 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
802 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
803 /* 64 bit ALU operations */
804 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
805 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
806 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
807 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
808 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
809 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
810 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
811 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
812 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
813 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
814 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
815 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
816 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
817 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
818 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
819 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
820 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
821 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
822 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
823 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
824 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
825 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
826 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
827 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
828 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
829 /* Call instruction */
830 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
831 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
832 /* Jumps */
833 [BPF_JMP | BPF_JA] = &&JMP_JA,
834 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
835 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
836 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
837 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
838 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
839 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
840 [BPF_JMP | BPF_JLT | BPF_X] = &&JMP_JLT_X,
841 [BPF_JMP | BPF_JLT | BPF_K] = &&JMP_JLT_K,
842 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
843 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
844 [BPF_JMP | BPF_JLE | BPF_X] = &&JMP_JLE_X,
845 [BPF_JMP | BPF_JLE | BPF_K] = &&JMP_JLE_K,
846 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
847 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
848 [BPF_JMP | BPF_JSLT | BPF_X] = &&JMP_JSLT_X,
849 [BPF_JMP | BPF_JSLT | BPF_K] = &&JMP_JSLT_K,
850 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
851 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
852 [BPF_JMP | BPF_JSLE | BPF_X] = &&JMP_JSLE_X,
853 [BPF_JMP | BPF_JSLE | BPF_K] = &&JMP_JSLE_K,
854 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
855 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
856 /* Program return */
857 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
858 /* Store instructions */
859 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
860 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
861 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
862 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
863 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
864 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
865 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
866 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
867 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
868 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
869 /* Load instructions */
870 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
871 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
872 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
873 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
874 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
875 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
876 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
877 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
878 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
879 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
880 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
881 };
882 u32 tail_call_cnt = 0;
883 void *ptr;
884 int off;
885
886 #define CONT ({ insn++; goto select_insn; })
887 #define CONT_JMP ({ insn++; goto select_insn; })
888
889 select_insn:
890 goto *jumptable[insn->code];
891
892 /* ALU */
893 #define ALU(OPCODE, OP) \
894 ALU64_##OPCODE##_X: \
895 DST = DST OP SRC; \
896 CONT; \
897 ALU_##OPCODE##_X: \
898 DST = (u32) DST OP (u32) SRC; \
899 CONT; \
900 ALU64_##OPCODE##_K: \
901 DST = DST OP IMM; \
902 CONT; \
903 ALU_##OPCODE##_K: \
904 DST = (u32) DST OP (u32) IMM; \
905 CONT;
906
907 ALU(ADD, +)
908 ALU(SUB, -)
909 ALU(AND, &)
910 ALU(OR, |)
911 ALU(LSH, <<)
912 ALU(RSH, >>)
913 ALU(XOR, ^)
914 ALU(MUL, *)
915 #undef ALU
916 ALU_NEG:
917 DST = (u32) -DST;
918 CONT;
919 ALU64_NEG:
920 DST = -DST;
921 CONT;
922 ALU_MOV_X:
923 DST = (u32) SRC;
924 CONT;
925 ALU_MOV_K:
926 DST = (u32) IMM;
927 CONT;
928 ALU64_MOV_X:
929 DST = SRC;
930 CONT;
931 ALU64_MOV_K:
932 DST = IMM;
933 CONT;
934 LD_IMM_DW:
935 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
936 insn++;
937 CONT;
938 ALU64_ARSH_X:
939 (*(s64 *) &DST) >>= SRC;
940 CONT;
941 ALU64_ARSH_K:
942 (*(s64 *) &DST) >>= IMM;
943 CONT;
944 ALU64_MOD_X:
945 if (unlikely(SRC == 0))
946 return 0;
947 div64_u64_rem(DST, SRC, &tmp);
948 DST = tmp;
949 CONT;
950 ALU_MOD_X:
951 if (unlikely(SRC == 0))
952 return 0;
953 tmp = (u32) DST;
954 DST = do_div(tmp, (u32) SRC);
955 CONT;
956 ALU64_MOD_K:
957 div64_u64_rem(DST, IMM, &tmp);
958 DST = tmp;
959 CONT;
960 ALU_MOD_K:
961 tmp = (u32) DST;
962 DST = do_div(tmp, (u32) IMM);
963 CONT;
964 ALU64_DIV_X:
965 if (unlikely(SRC == 0))
966 return 0;
967 DST = div64_u64(DST, SRC);
968 CONT;
969 ALU_DIV_X:
970 if (unlikely(SRC == 0))
971 return 0;
972 tmp = (u32) DST;
973 do_div(tmp, (u32) SRC);
974 DST = (u32) tmp;
975 CONT;
976 ALU64_DIV_K:
977 DST = div64_u64(DST, IMM);
978 CONT;
979 ALU_DIV_K:
980 tmp = (u32) DST;
981 do_div(tmp, (u32) IMM);
982 DST = (u32) tmp;
983 CONT;
984 ALU_END_TO_BE:
985 switch (IMM) {
986 case 16:
987 DST = (__force u16) cpu_to_be16(DST);
988 break;
989 case 32:
990 DST = (__force u32) cpu_to_be32(DST);
991 break;
992 case 64:
993 DST = (__force u64) cpu_to_be64(DST);
994 break;
995 }
996 CONT;
997 ALU_END_TO_LE:
998 switch (IMM) {
999 case 16:
1000 DST = (__force u16) cpu_to_le16(DST);
1001 break;
1002 case 32:
1003 DST = (__force u32) cpu_to_le32(DST);
1004 break;
1005 case 64:
1006 DST = (__force u64) cpu_to_le64(DST);
1007 break;
1008 }
1009 CONT;
1010
1011 /* CALL */
1012 JMP_CALL:
1013 /* Function call scratches BPF_R1-BPF_R5 registers,
1014 * preserves BPF_R6-BPF_R9, and stores return value
1015 * into BPF_R0.
1016 */
1017 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
1018 BPF_R4, BPF_R5);
1019 CONT;
1020
1021 JMP_TAIL_CALL: {
1022 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
1023 struct bpf_array *array = container_of(map, struct bpf_array, map);
1024 struct bpf_prog *prog;
1025 u64 index = BPF_R3;
1026
1027 if (unlikely(index >= array->map.max_entries))
1028 goto out;
1029 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
1030 goto out;
1031
1032 tail_call_cnt++;
1033
1034 prog = READ_ONCE(array->ptrs[index]);
1035 if (!prog)
1036 goto out;
1037
1038 /* ARG1 at this point is guaranteed to point to CTX from
1039 * the verifier side due to the fact that the tail call is
1040 * handeled like a helper, that is, bpf_tail_call_proto,
1041 * where arg1_type is ARG_PTR_TO_CTX.
1042 */
1043 insn = prog->insnsi;
1044 goto select_insn;
1045 out:
1046 CONT;
1047 }
1048 /* JMP */
1049 JMP_JA:
1050 insn += insn->off;
1051 CONT;
1052 JMP_JEQ_X:
1053 if (DST == SRC) {
1054 insn += insn->off;
1055 CONT_JMP;
1056 }
1057 CONT;
1058 JMP_JEQ_K:
1059 if (DST == IMM) {
1060 insn += insn->off;
1061 CONT_JMP;
1062 }
1063 CONT;
1064 JMP_JNE_X:
1065 if (DST != SRC) {
1066 insn += insn->off;
1067 CONT_JMP;
1068 }
1069 CONT;
1070 JMP_JNE_K:
1071 if (DST != IMM) {
1072 insn += insn->off;
1073 CONT_JMP;
1074 }
1075 CONT;
1076 JMP_JGT_X:
1077 if (DST > SRC) {
1078 insn += insn->off;
1079 CONT_JMP;
1080 }
1081 CONT;
1082 JMP_JGT_K:
1083 if (DST > IMM) {
1084 insn += insn->off;
1085 CONT_JMP;
1086 }
1087 CONT;
1088 JMP_JLT_X:
1089 if (DST < SRC) {
1090 insn += insn->off;
1091 CONT_JMP;
1092 }
1093 CONT;
1094 JMP_JLT_K:
1095 if (DST < IMM) {
1096 insn += insn->off;
1097 CONT_JMP;
1098 }
1099 CONT;
1100 JMP_JGE_X:
1101 if (DST >= SRC) {
1102 insn += insn->off;
1103 CONT_JMP;
1104 }
1105 CONT;
1106 JMP_JGE_K:
1107 if (DST >= IMM) {
1108 insn += insn->off;
1109 CONT_JMP;
1110 }
1111 CONT;
1112 JMP_JLE_X:
1113 if (DST <= SRC) {
1114 insn += insn->off;
1115 CONT_JMP;
1116 }
1117 CONT;
1118 JMP_JLE_K:
1119 if (DST <= IMM) {
1120 insn += insn->off;
1121 CONT_JMP;
1122 }
1123 CONT;
1124 JMP_JSGT_X:
1125 if (((s64) DST) > ((s64) SRC)) {
1126 insn += insn->off;
1127 CONT_JMP;
1128 }
1129 CONT;
1130 JMP_JSGT_K:
1131 if (((s64) DST) > ((s64) IMM)) {
1132 insn += insn->off;
1133 CONT_JMP;
1134 }
1135 CONT;
1136 JMP_JSLT_X:
1137 if (((s64) DST) < ((s64) SRC)) {
1138 insn += insn->off;
1139 CONT_JMP;
1140 }
1141 CONT;
1142 JMP_JSLT_K:
1143 if (((s64) DST) < ((s64) IMM)) {
1144 insn += insn->off;
1145 CONT_JMP;
1146 }
1147 CONT;
1148 JMP_JSGE_X:
1149 if (((s64) DST) >= ((s64) SRC)) {
1150 insn += insn->off;
1151 CONT_JMP;
1152 }
1153 CONT;
1154 JMP_JSGE_K:
1155 if (((s64) DST) >= ((s64) IMM)) {
1156 insn += insn->off;
1157 CONT_JMP;
1158 }
1159 CONT;
1160 JMP_JSLE_X:
1161 if (((s64) DST) <= ((s64) SRC)) {
1162 insn += insn->off;
1163 CONT_JMP;
1164 }
1165 CONT;
1166 JMP_JSLE_K:
1167 if (((s64) DST) <= ((s64) IMM)) {
1168 insn += insn->off;
1169 CONT_JMP;
1170 }
1171 CONT;
1172 JMP_JSET_X:
1173 if (DST & SRC) {
1174 insn += insn->off;
1175 CONT_JMP;
1176 }
1177 CONT;
1178 JMP_JSET_K:
1179 if (DST & IMM) {
1180 insn += insn->off;
1181 CONT_JMP;
1182 }
1183 CONT;
1184 JMP_EXIT:
1185 return BPF_R0;
1186
1187 /* STX and ST and LDX*/
1188 #define LDST(SIZEOP, SIZE) \
1189 STX_MEM_##SIZEOP: \
1190 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
1191 CONT; \
1192 ST_MEM_##SIZEOP: \
1193 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
1194 CONT; \
1195 LDX_MEM_##SIZEOP: \
1196 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
1197 CONT;
1198
1199 LDST(B, u8)
1200 LDST(H, u16)
1201 LDST(W, u32)
1202 LDST(DW, u64)
1203 #undef LDST
1204 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
1205 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
1206 (DST + insn->off));
1207 CONT;
1208 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
1209 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
1210 (DST + insn->off));
1211 CONT;
1212 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
1213 off = IMM;
1214 load_word:
1215 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only
1216 * appearing in the programs where ctx == skb
1217 * (see may_access_skb() in the verifier). All programs
1218 * keep 'ctx' in regs[BPF_REG_CTX] == BPF_R6,
1219 * bpf_convert_filter() saves it in BPF_R6, internal BPF
1220 * verifier will check that BPF_R6 == ctx.
1221 *
1222 * BPF_ABS and BPF_IND are wrappers of function calls,
1223 * so they scratch BPF_R1-BPF_R5 registers, preserve
1224 * BPF_R6-BPF_R9, and store return value into BPF_R0.
1225 *
1226 * Implicit input:
1227 * ctx == skb == BPF_R6 == CTX
1228 *
1229 * Explicit input:
1230 * SRC == any register
1231 * IMM == 32-bit immediate
1232 *
1233 * Output:
1234 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
1235 */
1236
1237 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
1238 if (likely(ptr != NULL)) {
1239 BPF_R0 = get_unaligned_be32(ptr);
1240 CONT;
1241 }
1242
1243 return 0;
1244 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
1245 off = IMM;
1246 load_half:
1247 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
1248 if (likely(ptr != NULL)) {
1249 BPF_R0 = get_unaligned_be16(ptr);
1250 CONT;
1251 }
1252
1253 return 0;
1254 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
1255 off = IMM;
1256 load_byte:
1257 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
1258 if (likely(ptr != NULL)) {
1259 BPF_R0 = *(u8 *)ptr;
1260 CONT;
1261 }
1262
1263 return 0;
1264 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
1265 off = IMM + SRC;
1266 goto load_word;
1267 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
1268 off = IMM + SRC;
1269 goto load_half;
1270 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
1271 off = IMM + SRC;
1272 goto load_byte;
1273
1274 default_label:
1275 /* If we ever reach this, we have a bug somewhere. */
1276 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
1277 return 0;
1278 }
1279 STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */
1280
1281 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
1282 #define DEFINE_BPF_PROG_RUN(stack_size) \
1283 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
1284 { \
1285 u64 stack[stack_size / sizeof(u64)]; \
1286 u64 regs[MAX_BPF_REG]; \
1287 \
1288 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1289 ARG1 = (u64) (unsigned long) ctx; \
1290 return ___bpf_prog_run(regs, insn, stack); \
1291 }
1292
1293 #define EVAL1(FN, X) FN(X)
1294 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
1295 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
1296 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
1297 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
1298 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
1299
1300 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
1301 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
1302 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
1303
1304 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
1305
1306 static unsigned int (*interpreters[])(const void *ctx,
1307 const struct bpf_insn *insn) = {
1308 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1309 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1310 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1311 };
1312
1313 bool bpf_prog_array_compatible(struct bpf_array *array,
1314 const struct bpf_prog *fp)
1315 {
1316 if (!array->owner_prog_type) {
1317 /* There's no owner yet where we could check for
1318 * compatibility.
1319 */
1320 array->owner_prog_type = fp->type;
1321 array->owner_jited = fp->jited;
1322
1323 return true;
1324 }
1325
1326 return array->owner_prog_type == fp->type &&
1327 array->owner_jited == fp->jited;
1328 }
1329
1330 static int bpf_check_tail_call(const struct bpf_prog *fp)
1331 {
1332 struct bpf_prog_aux *aux = fp->aux;
1333 int i;
1334
1335 for (i = 0; i < aux->used_map_cnt; i++) {
1336 struct bpf_map *map = aux->used_maps[i];
1337 struct bpf_array *array;
1338
1339 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
1340 continue;
1341
1342 array = container_of(map, struct bpf_array, map);
1343 if (!bpf_prog_array_compatible(array, fp))
1344 return -EINVAL;
1345 }
1346
1347 return 0;
1348 }
1349
1350 /**
1351 * bpf_prog_select_runtime - select exec runtime for BPF program
1352 * @fp: bpf_prog populated with internal BPF program
1353 * @err: pointer to error variable
1354 *
1355 * Try to JIT eBPF program, if JIT is not available, use interpreter.
1356 * The BPF program will be executed via BPF_PROG_RUN() macro.
1357 */
1358 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
1359 {
1360 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
1361
1362 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
1363
1364 /* eBPF JITs can rewrite the program in case constant
1365 * blinding is active. However, in case of error during
1366 * blinding, bpf_int_jit_compile() must always return a
1367 * valid program, which in this case would simply not
1368 * be JITed, but falls back to the interpreter.
1369 */
1370 fp = bpf_int_jit_compile(fp);
1371 bpf_prog_lock_ro(fp);
1372
1373 /* The tail call compatibility check can only be done at
1374 * this late stage as we need to determine, if we deal
1375 * with JITed or non JITed program concatenations and not
1376 * all eBPF JITs might immediately support all features.
1377 */
1378 *err = bpf_check_tail_call(fp);
1379
1380 return fp;
1381 }
1382 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
1383
1384 static void bpf_prog_free_deferred(struct work_struct *work)
1385 {
1386 struct bpf_prog_aux *aux;
1387
1388 aux = container_of(work, struct bpf_prog_aux, work);
1389 bpf_jit_free(aux->prog);
1390 }
1391
1392 /* Free internal BPF program */
1393 void bpf_prog_free(struct bpf_prog *fp)
1394 {
1395 struct bpf_prog_aux *aux = fp->aux;
1396
1397 INIT_WORK(&aux->work, bpf_prog_free_deferred);
1398 schedule_work(&aux->work);
1399 }
1400 EXPORT_SYMBOL_GPL(bpf_prog_free);
1401
1402 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
1403 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
1404
1405 void bpf_user_rnd_init_once(void)
1406 {
1407 prandom_init_once(&bpf_user_rnd_state);
1408 }
1409
1410 BPF_CALL_0(bpf_user_rnd_u32)
1411 {
1412 /* Should someone ever have the rather unwise idea to use some
1413 * of the registers passed into this function, then note that
1414 * this function is called from native eBPF and classic-to-eBPF
1415 * transformations. Register assignments from both sides are
1416 * different, f.e. classic always sets fn(ctx, A, X) here.
1417 */
1418 struct rnd_state *state;
1419 u32 res;
1420
1421 state = &get_cpu_var(bpf_user_rnd_state);
1422 res = prandom_u32_state(state);
1423 put_cpu_var(bpf_user_rnd_state);
1424
1425 return res;
1426 }
1427
1428 /* Weak definitions of helper functions in case we don't have bpf syscall. */
1429 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
1430 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
1431 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
1432
1433 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
1434 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
1435 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
1436 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
1437
1438 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
1439 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
1440 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
1441 const struct bpf_func_proto bpf_sock_map_update_proto __weak;
1442
1443 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
1444 {
1445 return NULL;
1446 }
1447
1448 u64 __weak
1449 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
1450 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
1451 {
1452 return -ENOTSUPP;
1453 }
1454
1455 /* Always built-in helper functions. */
1456 const struct bpf_func_proto bpf_tail_call_proto = {
1457 .func = NULL,
1458 .gpl_only = false,
1459 .ret_type = RET_VOID,
1460 .arg1_type = ARG_PTR_TO_CTX,
1461 .arg2_type = ARG_CONST_MAP_PTR,
1462 .arg3_type = ARG_ANYTHING,
1463 };
1464
1465 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
1466 * It is encouraged to implement bpf_int_jit_compile() instead, so that
1467 * eBPF and implicitly also cBPF can get JITed!
1468 */
1469 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
1470 {
1471 return prog;
1472 }
1473
1474 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
1475 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
1476 */
1477 void __weak bpf_jit_compile(struct bpf_prog *prog)
1478 {
1479 }
1480
1481 bool __weak bpf_helper_changes_pkt_data(void *func)
1482 {
1483 return false;
1484 }
1485
1486 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
1487 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
1488 */
1489 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
1490 int len)
1491 {
1492 return -EFAULT;
1493 }
1494
1495 /* All definitions of tracepoints related to BPF. */
1496 #define CREATE_TRACE_POINTS
1497 #include <linux/bpf_trace.h>
1498
1499 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
1500
1501 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type);
1502 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu);
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