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net/sctp: Always set scope_id in sctp_inet6_skb_msgname
[cris-mirror.git] / kernel / bpf / core.c
blob8a6c37762330f5d8f49214061e733f93e3c6a217
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 const char *end = sym + KSYM_NAME_LEN;
313
314 BUILD_BUG_ON(sizeof("bpf_prog_") +
315 sizeof(prog->tag) * 2 +
316 /* name has been null terminated.
317 * We should need +1 for the '_' preceding
318 * the name. However, the null character
319 * is double counted between the name and the
320 * sizeof("bpf_prog_") above, so we omit
321 * the +1 here.
322 */
323 sizeof(prog->aux->name) > KSYM_NAME_LEN);
324
325 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
326 sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
327 if (prog->aux->name[0])
328 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
329 else
330 *sym = 0;
331 }
332
333 static __always_inline unsigned long
334 bpf_get_prog_addr_start(struct latch_tree_node *n)
335 {
336 unsigned long symbol_start, symbol_end;
337 const struct bpf_prog_aux *aux;
338
339 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
340 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
341
342 return symbol_start;
343 }
344
345 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
346 struct latch_tree_node *b)
347 {
348 return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);
349 }
350
351 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
352 {
353 unsigned long val = (unsigned long)key;
354 unsigned long symbol_start, symbol_end;
355 const struct bpf_prog_aux *aux;
356
357 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
358 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
359
360 if (val < symbol_start)
361 return -1;
362 if (val >= symbol_end)
363 return 1;
364
365 return 0;
366 }
367
368 static const struct latch_tree_ops bpf_tree_ops = {
369 .less = bpf_tree_less,
370 .comp = bpf_tree_comp,
371 };
372
373 static DEFINE_SPINLOCK(bpf_lock);
374 static LIST_HEAD(bpf_kallsyms);
375 static struct latch_tree_root bpf_tree __cacheline_aligned;
376
377 int bpf_jit_kallsyms __read_mostly;
378
379 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
380 {
381 WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));
382 list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);
383 latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
384 }
385
386 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
387 {
388 if (list_empty(&aux->ksym_lnode))
389 return;
390
391 latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
392 list_del_rcu(&aux->ksym_lnode);
393 }
394
395 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
396 {
397 return fp->jited && !bpf_prog_was_classic(fp);
398 }
399
400 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
401 {
402 return list_empty(&fp->aux->ksym_lnode) ||
403 fp->aux->ksym_lnode.prev == LIST_POISON2;
404 }
405
406 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
407 {
408 if (!bpf_prog_kallsyms_candidate(fp) ||
409 !capable(CAP_SYS_ADMIN))
410 return;
411
412 spin_lock_bh(&bpf_lock);
413 bpf_prog_ksym_node_add(fp->aux);
414 spin_unlock_bh(&bpf_lock);
415 }
416
417 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
418 {
419 if (!bpf_prog_kallsyms_candidate(fp))
420 return;
421
422 spin_lock_bh(&bpf_lock);
423 bpf_prog_ksym_node_del(fp->aux);
424 spin_unlock_bh(&bpf_lock);
425 }
426
427 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
428 {
429 struct latch_tree_node *n;
430
431 if (!bpf_jit_kallsyms_enabled())
432 return NULL;
433
434 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
435 return n ?
436 container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :
437 NULL;
438 }
439
440 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
441 unsigned long *off, char *sym)
442 {
443 unsigned long symbol_start, symbol_end;
444 struct bpf_prog *prog;
445 char *ret = NULL;
446
447 rcu_read_lock();
448 prog = bpf_prog_kallsyms_find(addr);
449 if (prog) {
450 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
451 bpf_get_prog_name(prog, sym);
452
453 ret = sym;
454 if (size)
455 *size = symbol_end - symbol_start;
456 if (off)
457 *off = addr - symbol_start;
458 }
459 rcu_read_unlock();
460
461 return ret;
462 }
463
464 bool is_bpf_text_address(unsigned long addr)
465 {
466 bool ret;
467
468 rcu_read_lock();
469 ret = bpf_prog_kallsyms_find(addr) != NULL;
470 rcu_read_unlock();
471
472 return ret;
473 }
474
475 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
476 char *sym)
477 {
478 unsigned long symbol_start, symbol_end;
479 struct bpf_prog_aux *aux;
480 unsigned int it = 0;
481 int ret = -ERANGE;
482
483 if (!bpf_jit_kallsyms_enabled())
484 return ret;
485
486 rcu_read_lock();
487 list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {
488 if (it++ != symnum)
489 continue;
490
491 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
492 bpf_get_prog_name(aux->prog, sym);
493
494 *value = symbol_start;
495 *type = BPF_SYM_ELF_TYPE;
496
497 ret = 0;
498 break;
499 }
500 rcu_read_unlock();
501
502 return ret;
503 }
504
505 struct bpf_binary_header *
506 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
507 unsigned int alignment,
508 bpf_jit_fill_hole_t bpf_fill_ill_insns)
509 {
510 struct bpf_binary_header *hdr;
511 unsigned int size, hole, start;
512
513 /* Most of BPF filters are really small, but if some of them
514 * fill a page, allow at least 128 extra bytes to insert a
515 * random section of illegal instructions.
516 */
517 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
518 hdr = module_alloc(size);
519 if (hdr == NULL)
520 return NULL;
521
522 /* Fill space with illegal/arch-dep instructions. */
523 bpf_fill_ill_insns(hdr, size);
524
525 hdr->pages = size / PAGE_SIZE;
526 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
527 PAGE_SIZE - sizeof(*hdr));
528 start = (get_random_int() % hole) & ~(alignment - 1);
529
530 /* Leave a random number of instructions before BPF code. */
531 *image_ptr = &hdr->image[start];
532
533 return hdr;
534 }
535
536 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
537 {
538 module_memfree(hdr);
539 }
540
541 /* This symbol is only overridden by archs that have different
542 * requirements than the usual eBPF JITs, f.e. when they only
543 * implement cBPF JIT, do not set images read-only, etc.
544 */
545 void __weak bpf_jit_free(struct bpf_prog *fp)
546 {
547 if (fp->jited) {
548 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
549
550 bpf_jit_binary_unlock_ro(hdr);
551 bpf_jit_binary_free(hdr);
552
553 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
554 }
555
556 bpf_prog_unlock_free(fp);
557 }
558
559 int bpf_jit_harden __read_mostly;
560
561 static int bpf_jit_blind_insn(const struct bpf_insn *from,
562 const struct bpf_insn *aux,
563 struct bpf_insn *to_buff)
564 {
565 struct bpf_insn *to = to_buff;
566 u32 imm_rnd = get_random_int();
567 s16 off;
568
569 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
570 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
571
572 if (from->imm == 0 &&
573 (from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
574 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
575 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
576 goto out;
577 }
578
579 switch (from->code) {
580 case BPF_ALU | BPF_ADD | BPF_K:
581 case BPF_ALU | BPF_SUB | BPF_K:
582 case BPF_ALU | BPF_AND | BPF_K:
583 case BPF_ALU | BPF_OR | BPF_K:
584 case BPF_ALU | BPF_XOR | BPF_K:
585 case BPF_ALU | BPF_MUL | BPF_K:
586 case BPF_ALU | BPF_MOV | BPF_K:
587 case BPF_ALU | BPF_DIV | BPF_K:
588 case BPF_ALU | BPF_MOD | BPF_K:
589 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
590 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
591 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
592 break;
593
594 case BPF_ALU64 | BPF_ADD | BPF_K:
595 case BPF_ALU64 | BPF_SUB | BPF_K:
596 case BPF_ALU64 | BPF_AND | BPF_K:
597 case BPF_ALU64 | BPF_OR | BPF_K:
598 case BPF_ALU64 | BPF_XOR | BPF_K:
599 case BPF_ALU64 | BPF_MUL | BPF_K:
600 case BPF_ALU64 | BPF_MOV | BPF_K:
601 case BPF_ALU64 | BPF_DIV | BPF_K:
602 case BPF_ALU64 | BPF_MOD | BPF_K:
603 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
604 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
605 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
606 break;
607
608 case BPF_JMP | BPF_JEQ | BPF_K:
609 case BPF_JMP | BPF_JNE | BPF_K:
610 case BPF_JMP | BPF_JGT | BPF_K:
611 case BPF_JMP | BPF_JLT | BPF_K:
612 case BPF_JMP | BPF_JGE | BPF_K:
613 case BPF_JMP | BPF_JLE | BPF_K:
614 case BPF_JMP | BPF_JSGT | BPF_K:
615 case BPF_JMP | BPF_JSLT | BPF_K:
616 case BPF_JMP | BPF_JSGE | BPF_K:
617 case BPF_JMP | BPF_JSLE | BPF_K:
618 case BPF_JMP | BPF_JSET | BPF_K:
619 /* Accommodate for extra offset in case of a backjump. */
620 off = from->off;
621 if (off < 0)
622 off -= 2;
623 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
624 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
625 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
626 break;
627
628 case BPF_LD | BPF_ABS | BPF_W:
629 case BPF_LD | BPF_ABS | BPF_H:
630 case BPF_LD | BPF_ABS | BPF_B:
631 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
632 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
633 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
634 break;
635
636 case BPF_LD | BPF_IND | BPF_W:
637 case BPF_LD | BPF_IND | BPF_H:
638 case BPF_LD | BPF_IND | BPF_B:
639 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
640 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
641 *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
642 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
643 break;
644
645 case BPF_LD | BPF_IMM | BPF_DW:
646 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
647 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
648 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
649 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
650 break;
651 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
652 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
653 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
654 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
655 break;
656
657 case BPF_ST | BPF_MEM | BPF_DW:
658 case BPF_ST | BPF_MEM | BPF_W:
659 case BPF_ST | BPF_MEM | BPF_H:
660 case BPF_ST | BPF_MEM | BPF_B:
661 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
662 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
663 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
664 break;
665 }
666 out:
667 return to - to_buff;
668 }
669
670 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
671 gfp_t gfp_extra_flags)
672 {
673 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
674 struct bpf_prog *fp;
675
676 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
677 if (fp != NULL) {
678 kmemcheck_annotate_bitfield(fp, meta);
679
680 /* aux->prog still points to the fp_other one, so
681 * when promoting the clone to the real program,
682 * this still needs to be adapted.
683 */
684 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
685 }
686
687 return fp;
688 }
689
690 static void bpf_prog_clone_free(struct bpf_prog *fp)
691 {
692 /* aux was stolen by the other clone, so we cannot free
693 * it from this path! It will be freed eventually by the
694 * other program on release.
695 *
696 * At this point, we don't need a deferred release since
697 * clone is guaranteed to not be locked.
698 */
699 fp->aux = NULL;
700 __bpf_prog_free(fp);
701 }
702
703 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
704 {
705 /* We have to repoint aux->prog to self, as we don't
706 * know whether fp here is the clone or the original.
707 */
708 fp->aux->prog = fp;
709 bpf_prog_clone_free(fp_other);
710 }
711
712 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
713 {
714 struct bpf_insn insn_buff[16], aux[2];
715 struct bpf_prog *clone, *tmp;
716 int insn_delta, insn_cnt;
717 struct bpf_insn *insn;
718 int i, rewritten;
719
720 if (!bpf_jit_blinding_enabled())
721 return prog;
722
723 clone = bpf_prog_clone_create(prog, GFP_USER);
724 if (!clone)
725 return ERR_PTR(-ENOMEM);
726
727 insn_cnt = clone->len;
728 insn = clone->insnsi;
729
730 for (i = 0; i < insn_cnt; i++, insn++) {
731 /* We temporarily need to hold the original ld64 insn
732 * so that we can still access the first part in the
733 * second blinding run.
734 */
735 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
736 insn[1].code == 0)
737 memcpy(aux, insn, sizeof(aux));
738
739 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
740 if (!rewritten)
741 continue;
742
743 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
744 if (!tmp) {
745 /* Patching may have repointed aux->prog during
746 * realloc from the original one, so we need to
747 * fix it up here on error.
748 */
749 bpf_jit_prog_release_other(prog, clone);
750 return ERR_PTR(-ENOMEM);
751 }
752
753 clone = tmp;
754 insn_delta = rewritten - 1;
755
756 /* Walk new program and skip insns we just inserted. */
757 insn = clone->insnsi + i + insn_delta;
758 insn_cnt += insn_delta;
759 i += insn_delta;
760 }
761
762 return clone;
763 }
764 #endif /* CONFIG_BPF_JIT */
765
766 /* Base function for offset calculation. Needs to go into .text section,
767 * therefore keeping it non-static as well; will also be used by JITs
768 * anyway later on, so do not let the compiler omit it.
769 */
770 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
771 {
772 return 0;
773 }
774 EXPORT_SYMBOL_GPL(__bpf_call_base);
775
776 /**
777 * __bpf_prog_run - run eBPF program on a given context
778 * @ctx: is the data we are operating on
779 * @insn: is the array of eBPF instructions
780 *
781 * Decode and execute eBPF instructions.
782 */
783 static unsigned int ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn,
784 u64 *stack)
785 {
786 u64 tmp;
787 static const void *jumptable[256] = {
788 [0 ... 255] = &&default_label,
789 /* Now overwrite non-defaults ... */
790 /* 32 bit ALU operations */
791 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
792 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
793 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
794 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
795 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
796 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
797 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
798 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
799 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
800 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
801 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
802 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
803 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
804 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
805 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
806 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
807 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
808 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
809 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
810 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
811 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
812 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
813 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
814 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
815 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
816 /* 64 bit ALU operations */
817 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
818 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
819 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
820 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
821 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
822 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
823 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
824 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
825 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
826 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
827 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
828 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
829 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
830 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
831 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
832 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
833 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
834 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
835 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
836 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
837 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
838 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
839 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
840 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
841 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
842 /* Call instruction */
843 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
844 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
845 /* Jumps */
846 [BPF_JMP | BPF_JA] = &&JMP_JA,
847 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
848 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
849 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
850 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
851 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
852 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
853 [BPF_JMP | BPF_JLT | BPF_X] = &&JMP_JLT_X,
854 [BPF_JMP | BPF_JLT | BPF_K] = &&JMP_JLT_K,
855 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
856 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
857 [BPF_JMP | BPF_JLE | BPF_X] = &&JMP_JLE_X,
858 [BPF_JMP | BPF_JLE | BPF_K] = &&JMP_JLE_K,
859 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
860 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
861 [BPF_JMP | BPF_JSLT | BPF_X] = &&JMP_JSLT_X,
862 [BPF_JMP | BPF_JSLT | BPF_K] = &&JMP_JSLT_K,
863 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
864 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
865 [BPF_JMP | BPF_JSLE | BPF_X] = &&JMP_JSLE_X,
866 [BPF_JMP | BPF_JSLE | BPF_K] = &&JMP_JSLE_K,
867 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
868 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
869 /* Program return */
870 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
871 /* Store instructions */
872 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
873 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
874 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
875 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
876 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
877 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
878 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
879 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
880 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
881 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
882 /* Load instructions */
883 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
884 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
885 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
886 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
887 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
888 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
889 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
890 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
891 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
892 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
893 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
894 };
895 u32 tail_call_cnt = 0;
896 void *ptr;
897 int off;
898
899 #define CONT ({ insn++; goto select_insn; })
900 #define CONT_JMP ({ insn++; goto select_insn; })
901
902 select_insn:
903 goto *jumptable[insn->code];
904
905 /* ALU */
906 #define ALU(OPCODE, OP) \
907 ALU64_##OPCODE##_X: \
908 DST = DST OP SRC; \
909 CONT; \
910 ALU_##OPCODE##_X: \
911 DST = (u32) DST OP (u32) SRC; \
912 CONT; \
913 ALU64_##OPCODE##_K: \
914 DST = DST OP IMM; \
915 CONT; \
916 ALU_##OPCODE##_K: \
917 DST = (u32) DST OP (u32) IMM; \
918 CONT;
919
920 ALU(ADD, +)
921 ALU(SUB, -)
922 ALU(AND, &)
923 ALU(OR, |)
924 ALU(LSH, <<)
925 ALU(RSH, >>)
926 ALU(XOR, ^)
927 ALU(MUL, *)
928 #undef ALU
929 ALU_NEG:
930 DST = (u32) -DST;
931 CONT;
932 ALU64_NEG:
933 DST = -DST;
934 CONT;
935 ALU_MOV_X:
936 DST = (u32) SRC;
937 CONT;
938 ALU_MOV_K:
939 DST = (u32) IMM;
940 CONT;
941 ALU64_MOV_X:
942 DST = SRC;
943 CONT;
944 ALU64_MOV_K:
945 DST = IMM;
946 CONT;
947 LD_IMM_DW:
948 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
949 insn++;
950 CONT;
951 ALU64_ARSH_X:
952 (*(s64 *) &DST) >>= SRC;
953 CONT;
954 ALU64_ARSH_K:
955 (*(s64 *) &DST) >>= IMM;
956 CONT;
957 ALU64_MOD_X:
958 if (unlikely(SRC == 0))
959 return 0;
960 div64_u64_rem(DST, SRC, &tmp);
961 DST = tmp;
962 CONT;
963 ALU_MOD_X:
964 if (unlikely(SRC == 0))
965 return 0;
966 tmp = (u32) DST;
967 DST = do_div(tmp, (u32) SRC);
968 CONT;
969 ALU64_MOD_K:
970 div64_u64_rem(DST, IMM, &tmp);
971 DST = tmp;
972 CONT;
973 ALU_MOD_K:
974 tmp = (u32) DST;
975 DST = do_div(tmp, (u32) IMM);
976 CONT;
977 ALU64_DIV_X:
978 if (unlikely(SRC == 0))
979 return 0;
980 DST = div64_u64(DST, SRC);
981 CONT;
982 ALU_DIV_X:
983 if (unlikely(SRC == 0))
984 return 0;
985 tmp = (u32) DST;
986 do_div(tmp, (u32) SRC);
987 DST = (u32) tmp;
988 CONT;
989 ALU64_DIV_K:
990 DST = div64_u64(DST, IMM);
991 CONT;
992 ALU_DIV_K:
993 tmp = (u32) DST;
994 do_div(tmp, (u32) IMM);
995 DST = (u32) tmp;
996 CONT;
997 ALU_END_TO_BE:
998 switch (IMM) {
999 case 16:
1000 DST = (__force u16) cpu_to_be16(DST);
1001 break;
1002 case 32:
1003 DST = (__force u32) cpu_to_be32(DST);
1004 break;
1005 case 64:
1006 DST = (__force u64) cpu_to_be64(DST);
1007 break;
1008 }
1009 CONT;
1010 ALU_END_TO_LE:
1011 switch (IMM) {
1012 case 16:
1013 DST = (__force u16) cpu_to_le16(DST);
1014 break;
1015 case 32:
1016 DST = (__force u32) cpu_to_le32(DST);
1017 break;
1018 case 64:
1019 DST = (__force u64) cpu_to_le64(DST);
1020 break;
1021 }
1022 CONT;
1023
1024 /* CALL */
1025 JMP_CALL:
1026 /* Function call scratches BPF_R1-BPF_R5 registers,
1027 * preserves BPF_R6-BPF_R9, and stores return value
1028 * into BPF_R0.
1029 */
1030 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
1031 BPF_R4, BPF_R5);
1032 CONT;
1033
1034 JMP_TAIL_CALL: {
1035 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
1036 struct bpf_array *array = container_of(map, struct bpf_array, map);
1037 struct bpf_prog *prog;
1038 u32 index = BPF_R3;
1039
1040 if (unlikely(index >= array->map.max_entries))
1041 goto out;
1042 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
1043 goto out;
1044
1045 tail_call_cnt++;
1046
1047 prog = READ_ONCE(array->ptrs[index]);
1048 if (!prog)
1049 goto out;
1050
1051 /* ARG1 at this point is guaranteed to point to CTX from
1052 * the verifier side due to the fact that the tail call is
1053 * handeled like a helper, that is, bpf_tail_call_proto,
1054 * where arg1_type is ARG_PTR_TO_CTX.
1055 */
1056 insn = prog->insnsi;
1057 goto select_insn;
1058 out:
1059 CONT;
1060 }
1061 /* JMP */
1062 JMP_JA:
1063 insn += insn->off;
1064 CONT;
1065 JMP_JEQ_X:
1066 if (DST == SRC) {
1067 insn += insn->off;
1068 CONT_JMP;
1069 }
1070 CONT;
1071 JMP_JEQ_K:
1072 if (DST == IMM) {
1073 insn += insn->off;
1074 CONT_JMP;
1075 }
1076 CONT;
1077 JMP_JNE_X:
1078 if (DST != SRC) {
1079 insn += insn->off;
1080 CONT_JMP;
1081 }
1082 CONT;
1083 JMP_JNE_K:
1084 if (DST != IMM) {
1085 insn += insn->off;
1086 CONT_JMP;
1087 }
1088 CONT;
1089 JMP_JGT_X:
1090 if (DST > SRC) {
1091 insn += insn->off;
1092 CONT_JMP;
1093 }
1094 CONT;
1095 JMP_JGT_K:
1096 if (DST > IMM) {
1097 insn += insn->off;
1098 CONT_JMP;
1099 }
1100 CONT;
1101 JMP_JLT_X:
1102 if (DST < SRC) {
1103 insn += insn->off;
1104 CONT_JMP;
1105 }
1106 CONT;
1107 JMP_JLT_K:
1108 if (DST < IMM) {
1109 insn += insn->off;
1110 CONT_JMP;
1111 }
1112 CONT;
1113 JMP_JGE_X:
1114 if (DST >= SRC) {
1115 insn += insn->off;
1116 CONT_JMP;
1117 }
1118 CONT;
1119 JMP_JGE_K:
1120 if (DST >= IMM) {
1121 insn += insn->off;
1122 CONT_JMP;
1123 }
1124 CONT;
1125 JMP_JLE_X:
1126 if (DST <= SRC) {
1127 insn += insn->off;
1128 CONT_JMP;
1129 }
1130 CONT;
1131 JMP_JLE_K:
1132 if (DST <= IMM) {
1133 insn += insn->off;
1134 CONT_JMP;
1135 }
1136 CONT;
1137 JMP_JSGT_X:
1138 if (((s64) DST) > ((s64) SRC)) {
1139 insn += insn->off;
1140 CONT_JMP;
1141 }
1142 CONT;
1143 JMP_JSGT_K:
1144 if (((s64) DST) > ((s64) IMM)) {
1145 insn += insn->off;
1146 CONT_JMP;
1147 }
1148 CONT;
1149 JMP_JSLT_X:
1150 if (((s64) DST) < ((s64) SRC)) {
1151 insn += insn->off;
1152 CONT_JMP;
1153 }
1154 CONT;
1155 JMP_JSLT_K:
1156 if (((s64) DST) < ((s64) IMM)) {
1157 insn += insn->off;
1158 CONT_JMP;
1159 }
1160 CONT;
1161 JMP_JSGE_X:
1162 if (((s64) DST) >= ((s64) SRC)) {
1163 insn += insn->off;
1164 CONT_JMP;
1165 }
1166 CONT;
1167 JMP_JSGE_K:
1168 if (((s64) DST) >= ((s64) IMM)) {
1169 insn += insn->off;
1170 CONT_JMP;
1171 }
1172 CONT;
1173 JMP_JSLE_X:
1174 if (((s64) DST) <= ((s64) SRC)) {
1175 insn += insn->off;
1176 CONT_JMP;
1177 }
1178 CONT;
1179 JMP_JSLE_K:
1180 if (((s64) DST) <= ((s64) IMM)) {
1181 insn += insn->off;
1182 CONT_JMP;
1183 }
1184 CONT;
1185 JMP_JSET_X:
1186 if (DST & SRC) {
1187 insn += insn->off;
1188 CONT_JMP;
1189 }
1190 CONT;
1191 JMP_JSET_K:
1192 if (DST & IMM) {
1193 insn += insn->off;
1194 CONT_JMP;
1195 }
1196 CONT;
1197 JMP_EXIT:
1198 return BPF_R0;
1199
1200 /* STX and ST and LDX*/
1201 #define LDST(SIZEOP, SIZE) \
1202 STX_MEM_##SIZEOP: \
1203 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
1204 CONT; \
1205 ST_MEM_##SIZEOP: \
1206 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
1207 CONT; \
1208 LDX_MEM_##SIZEOP: \
1209 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
1210 CONT;
1211
1212 LDST(B, u8)
1213 LDST(H, u16)
1214 LDST(W, u32)
1215 LDST(DW, u64)
1216 #undef LDST
1217 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
1218 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
1219 (DST + insn->off));
1220 CONT;
1221 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
1222 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
1223 (DST + insn->off));
1224 CONT;
1225 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
1226 off = IMM;
1227 load_word:
1228 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only
1229 * appearing in the programs where ctx == skb
1230 * (see may_access_skb() in the verifier). All programs
1231 * keep 'ctx' in regs[BPF_REG_CTX] == BPF_R6,
1232 * bpf_convert_filter() saves it in BPF_R6, internal BPF
1233 * verifier will check that BPF_R6 == ctx.
1234 *
1235 * BPF_ABS and BPF_IND are wrappers of function calls,
1236 * so they scratch BPF_R1-BPF_R5 registers, preserve
1237 * BPF_R6-BPF_R9, and store return value into BPF_R0.
1238 *
1239 * Implicit input:
1240 * ctx == skb == BPF_R6 == CTX
1241 *
1242 * Explicit input:
1243 * SRC == any register
1244 * IMM == 32-bit immediate
1245 *
1246 * Output:
1247 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
1248 */
1249
1250 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
1251 if (likely(ptr != NULL)) {
1252 BPF_R0 = get_unaligned_be32(ptr);
1253 CONT;
1254 }
1255
1256 return 0;
1257 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
1258 off = IMM;
1259 load_half:
1260 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
1261 if (likely(ptr != NULL)) {
1262 BPF_R0 = get_unaligned_be16(ptr);
1263 CONT;
1264 }
1265
1266 return 0;
1267 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
1268 off = IMM;
1269 load_byte:
1270 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
1271 if (likely(ptr != NULL)) {
1272 BPF_R0 = *(u8 *)ptr;
1273 CONT;
1274 }
1275
1276 return 0;
1277 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
1278 off = IMM + SRC;
1279 goto load_word;
1280 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
1281 off = IMM + SRC;
1282 goto load_half;
1283 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
1284 off = IMM + SRC;
1285 goto load_byte;
1286
1287 default_label:
1288 /* If we ever reach this, we have a bug somewhere. */
1289 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
1290 return 0;
1291 }
1292 STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */
1293
1294 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
1295 #define DEFINE_BPF_PROG_RUN(stack_size) \
1296 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
1297 { \
1298 u64 stack[stack_size / sizeof(u64)]; \
1299 u64 regs[MAX_BPF_REG]; \
1300 \
1301 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1302 ARG1 = (u64) (unsigned long) ctx; \
1303 return ___bpf_prog_run(regs, insn, stack); \
1304 }
1305
1306 #define EVAL1(FN, X) FN(X)
1307 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
1308 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
1309 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
1310 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
1311 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
1312
1313 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
1314 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
1315 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
1316
1317 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
1318
1319 static unsigned int (*interpreters[])(const void *ctx,
1320 const struct bpf_insn *insn) = {
1321 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1322 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1323 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1324 };
1325
1326 bool bpf_prog_array_compatible(struct bpf_array *array,
1327 const struct bpf_prog *fp)
1328 {
1329 if (!array->owner_prog_type) {
1330 /* There's no owner yet where we could check for
1331 * compatibility.
1332 */
1333 array->owner_prog_type = fp->type;
1334 array->owner_jited = fp->jited;
1335
1336 return true;
1337 }
1338
1339 return array->owner_prog_type == fp->type &&
1340 array->owner_jited == fp->jited;
1341 }
1342
1343 static int bpf_check_tail_call(const struct bpf_prog *fp)
1344 {
1345 struct bpf_prog_aux *aux = fp->aux;
1346 int i;
1347
1348 for (i = 0; i < aux->used_map_cnt; i++) {
1349 struct bpf_map *map = aux->used_maps[i];
1350 struct bpf_array *array;
1351
1352 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
1353 continue;
1354
1355 array = container_of(map, struct bpf_array, map);
1356 if (!bpf_prog_array_compatible(array, fp))
1357 return -EINVAL;
1358 }
1359
1360 return 0;
1361 }
1362
1363 /**
1364 * bpf_prog_select_runtime - select exec runtime for BPF program
1365 * @fp: bpf_prog populated with internal BPF program
1366 * @err: pointer to error variable
1367 *
1368 * Try to JIT eBPF program, if JIT is not available, use interpreter.
1369 * The BPF program will be executed via BPF_PROG_RUN() macro.
1370 */
1371 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
1372 {
1373 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
1374
1375 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
1376
1377 /* eBPF JITs can rewrite the program in case constant
1378 * blinding is active. However, in case of error during
1379 * blinding, bpf_int_jit_compile() must always return a
1380 * valid program, which in this case would simply not
1381 * be JITed, but falls back to the interpreter.
1382 */
1383 if (!bpf_prog_is_dev_bound(fp->aux)) {
1384 fp = bpf_int_jit_compile(fp);
1385 } else {
1386 *err = bpf_prog_offload_compile(fp);
1387 if (*err)
1388 return fp;
1389 }
1390 bpf_prog_lock_ro(fp);
1391
1392 /* The tail call compatibility check can only be done at
1393 * this late stage as we need to determine, if we deal
1394 * with JITed or non JITed program concatenations and not
1395 * all eBPF JITs might immediately support all features.
1396 */
1397 *err = bpf_check_tail_call(fp);
1398
1399 return fp;
1400 }
1401 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
1402
1403 static unsigned int __bpf_prog_ret1(const void *ctx,
1404 const struct bpf_insn *insn)
1405 {
1406 return 1;
1407 }
1408
1409 static struct bpf_prog_dummy {
1410 struct bpf_prog prog;
1411 } dummy_bpf_prog = {
1412 .prog = {
1413 .bpf_func = __bpf_prog_ret1,
1414 },
1415 };
1416
1417 /* to avoid allocating empty bpf_prog_array for cgroups that
1418 * don't have bpf program attached use one global 'empty_prog_array'
1419 * It will not be modified the caller of bpf_prog_array_alloc()
1420 * (since caller requested prog_cnt == 0)
1421 * that pointer should be 'freed' by bpf_prog_array_free()
1422 */
1423 static struct {
1424 struct bpf_prog_array hdr;
1425 struct bpf_prog *null_prog;
1426 } empty_prog_array = {
1427 .null_prog = NULL,
1428 };
1429
1430 struct bpf_prog_array __rcu *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
1431 {
1432 if (prog_cnt)
1433 return kzalloc(sizeof(struct bpf_prog_array) +
1434 sizeof(struct bpf_prog *) * (prog_cnt + 1),
1435 flags);
1436
1437 return &empty_prog_array.hdr;
1438 }
1439
1440 void bpf_prog_array_free(struct bpf_prog_array __rcu *progs)
1441 {
1442 if (!progs ||
1443 progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr)
1444 return;
1445 kfree_rcu(progs, rcu);
1446 }
1447
1448 int bpf_prog_array_length(struct bpf_prog_array __rcu *progs)
1449 {
1450 struct bpf_prog **prog;
1451 u32 cnt = 0;
1452
1453 rcu_read_lock();
1454 prog = rcu_dereference(progs)->progs;
1455 for (; *prog; prog++)
1456 cnt++;
1457 rcu_read_unlock();
1458 return cnt;
1459 }
1460
1461 int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,
1462 __u32 __user *prog_ids, u32 cnt)
1463 {
1464 struct bpf_prog **prog;
1465 u32 i = 0, id;
1466
1467 rcu_read_lock();
1468 prog = rcu_dereference(progs)->progs;
1469 for (; *prog; prog++) {
1470 id = (*prog)->aux->id;
1471 if (copy_to_user(prog_ids + i, &id, sizeof(id))) {
1472 rcu_read_unlock();
1473 return -EFAULT;
1474 }
1475 if (++i == cnt) {
1476 prog++;
1477 break;
1478 }
1479 }
1480 rcu_read_unlock();
1481 if (*prog)
1482 return -ENOSPC;
1483 return 0;
1484 }
1485
1486 void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs,
1487 struct bpf_prog *old_prog)
1488 {
1489 struct bpf_prog **prog = progs->progs;
1490
1491 for (; *prog; prog++)
1492 if (*prog == old_prog) {
1493 WRITE_ONCE(*prog, &dummy_bpf_prog.prog);
1494 break;
1495 }
1496 }
1497
1498 int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
1499 struct bpf_prog *exclude_prog,
1500 struct bpf_prog *include_prog,
1501 struct bpf_prog_array **new_array)
1502 {
1503 int new_prog_cnt, carry_prog_cnt = 0;
1504 struct bpf_prog **existing_prog;
1505 struct bpf_prog_array *array;
1506 int new_prog_idx = 0;
1507
1508 /* Figure out how many existing progs we need to carry over to
1509 * the new array.
1510 */
1511 if (old_array) {
1512 existing_prog = old_array->progs;
1513 for (; *existing_prog; existing_prog++) {
1514 if (*existing_prog != exclude_prog &&
1515 *existing_prog != &dummy_bpf_prog.prog)
1516 carry_prog_cnt++;
1517 if (*existing_prog == include_prog)
1518 return -EEXIST;
1519 }
1520 }
1521
1522 /* How many progs (not NULL) will be in the new array? */
1523 new_prog_cnt = carry_prog_cnt;
1524 if (include_prog)
1525 new_prog_cnt += 1;
1526
1527 /* Do we have any prog (not NULL) in the new array? */
1528 if (!new_prog_cnt) {
1529 *new_array = NULL;
1530 return 0;
1531 }
1532
1533 /* +1 as the end of prog_array is marked with NULL */
1534 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
1535 if (!array)
1536 return -ENOMEM;
1537
1538 /* Fill in the new prog array */
1539 if (carry_prog_cnt) {
1540 existing_prog = old_array->progs;
1541 for (; *existing_prog; existing_prog++)
1542 if (*existing_prog != exclude_prog &&
1543 *existing_prog != &dummy_bpf_prog.prog)
1544 array->progs[new_prog_idx++] = *existing_prog;
1545 }
1546 if (include_prog)
1547 array->progs[new_prog_idx++] = include_prog;
1548 array->progs[new_prog_idx] = NULL;
1549 *new_array = array;
1550 return 0;
1551 }
1552
1553 static void bpf_prog_free_deferred(struct work_struct *work)
1554 {
1555 struct bpf_prog_aux *aux;
1556
1557 aux = container_of(work, struct bpf_prog_aux, work);
1558 if (bpf_prog_is_dev_bound(aux))
1559 bpf_prog_offload_destroy(aux->prog);
1560 bpf_jit_free(aux->prog);
1561 }
1562
1563 /* Free internal BPF program */
1564 void bpf_prog_free(struct bpf_prog *fp)
1565 {
1566 struct bpf_prog_aux *aux = fp->aux;
1567
1568 INIT_WORK(&aux->work, bpf_prog_free_deferred);
1569 schedule_work(&aux->work);
1570 }
1571 EXPORT_SYMBOL_GPL(bpf_prog_free);
1572
1573 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
1574 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
1575
1576 void bpf_user_rnd_init_once(void)
1577 {
1578 prandom_init_once(&bpf_user_rnd_state);
1579 }
1580
1581 BPF_CALL_0(bpf_user_rnd_u32)
1582 {
1583 /* Should someone ever have the rather unwise idea to use some
1584 * of the registers passed into this function, then note that
1585 * this function is called from native eBPF and classic-to-eBPF
1586 * transformations. Register assignments from both sides are
1587 * different, f.e. classic always sets fn(ctx, A, X) here.
1588 */
1589 struct rnd_state *state;
1590 u32 res;
1591
1592 state = &get_cpu_var(bpf_user_rnd_state);
1593 res = prandom_u32_state(state);
1594 put_cpu_var(bpf_user_rnd_state);
1595
1596 return res;
1597 }
1598
1599 /* Weak definitions of helper functions in case we don't have bpf syscall. */
1600 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
1601 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
1602 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
1603
1604 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
1605 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
1606 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
1607 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
1608
1609 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
1610 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
1611 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
1612 const struct bpf_func_proto bpf_sock_map_update_proto __weak;
1613
1614 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
1615 {
1616 return NULL;
1617 }
1618
1619 u64 __weak
1620 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
1621 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
1622 {
1623 return -ENOTSUPP;
1624 }
1625
1626 /* Always built-in helper functions. */
1627 const struct bpf_func_proto bpf_tail_call_proto = {
1628 .func = NULL,
1629 .gpl_only = false,
1630 .ret_type = RET_VOID,
1631 .arg1_type = ARG_PTR_TO_CTX,
1632 .arg2_type = ARG_CONST_MAP_PTR,
1633 .arg3_type = ARG_ANYTHING,
1634 };
1635
1636 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
1637 * It is encouraged to implement bpf_int_jit_compile() instead, so that
1638 * eBPF and implicitly also cBPF can get JITed!
1639 */
1640 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
1641 {
1642 return prog;
1643 }
1644
1645 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
1646 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
1647 */
1648 void __weak bpf_jit_compile(struct bpf_prog *prog)
1649 {
1650 }
1651
1652 bool __weak bpf_helper_changes_pkt_data(void *func)
1653 {
1654 return false;
1655 }
1656
1657 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
1658 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
1659 */
1660 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
1661 int len)
1662 {
1663 return -EFAULT;
1664 }
1665
1666 /* All definitions of tracepoints related to BPF. */
1667 #define CREATE_TRACE_POINTS
1668 #include <linux/bpf_trace.h>
1669
1670 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
1671
1672 /* These are only used within the BPF_SYSCALL code */
1673 #ifdef CONFIG_BPF_SYSCALL
1674 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type);
1675 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu);
1676 #endif
CRIS linux kernel tree