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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 *

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 #include <linux/perf_event.h>

35

36 #include <asm/unaligned.h>

37

38 /* Registers */

39 #define BPF_R0 regs[BPF_REG_0]

40 #define BPF_R1 regs[BPF_REG_1]

41 #define BPF_R2 regs[BPF_REG_2]

42 #define BPF_R3 regs[BPF_REG_3]

43 #define BPF_R4 regs[BPF_REG_4]

44 #define BPF_R5 regs[BPF_REG_5]

45 #define BPF_R6 regs[BPF_REG_6]

46 #define BPF_R7 regs[BPF_REG_7]

47 #define BPF_R8 regs[BPF_REG_8]

48 #define BPF_R9 regs[BPF_REG_9]

49 #define BPF_R10 regs[BPF_REG_10]

50

51 /* Named registers */

52 #define DST regs[insn->dst_reg]

53 #define SRC regs[insn->src_reg]

54 #define FP regs[BPF_REG_FP]

55 #define ARG1 regs[BPF_REG_ARG1]

56 #define CTX regs[BPF_REG_CTX]

57 #define IMM insn->imm

58

59 /* No hurry in this branch

60 *

61 * Exported for the bpf jit load helper.

62 */

63 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)

64 {

65 u8 *ptr = NULL;

66

67 if (k >= SKF_NET_OFF)

68 ptr = skb_network_header(skb) + k - SKF_NET_OFF;

69 else if (k >= SKF_LL_OFF)

70 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;

71

72 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))

73 return ptr;

74

75 return NULL;

76 }

77

78 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)

79 {

80 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;

81 struct bpf_prog_aux *aux;

82 struct bpf_prog *fp;

83

84 size = round_up(size, PAGE_SIZE);

85 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);

86 if (fp == NULL)

87 return NULL;

88

89 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);

90 if (aux == NULL) {

91 vfree(fp);

92 return NULL;

93 }

94

95 fp->pages = size / PAGE_SIZE;

96 fp->aux = aux;

97 fp->aux->prog = fp;

98 fp->jit_requested = ebpf_jit_enabled();

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 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);

131 fp->pages = pages;

132 fp->aux->prog = fp;

133

134 /* We keep fp->aux from fp_old around in the new

135 * reallocated structure.

136 */

137 fp_old->aux = NULL;

138 __bpf_prog_free(fp_old);

139 }

140

141 return fp;

142 }

143

144 void __bpf_prog_free(struct bpf_prog *fp)

145 {

146 kfree(fp->aux);

147 vfree(fp);

148 }

149

150 int bpf_prog_calc_tag(struct bpf_prog *fp)

151 {

152 const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);

153 u32 raw_size = bpf_prog_tag_scratch_size(fp);

154 u32 digest[SHA_DIGEST_WORDS];

155 u32 ws[SHA_WORKSPACE_WORDS];

156 u32 i, bsize, psize, blocks;

157 struct bpf_insn *dst;

158 bool was_ld_map;

159 u8 *raw, *todo;

160 __be32 *result;

161 __be64 *bits;

162

163 raw = vmalloc(raw_size);

164 if (!raw)

165 return -ENOMEM;

166

167 sha_init(digest);

168 memset(ws, 0, sizeof(ws));

169

170 /* We need to take out the map fd for the digest calculation

171 * since they are unstable from user space side.

172 */

173 dst = (void *)raw;

174 for (i = 0, was_ld_map = false; i < fp->len; i++) {

175 dst[i] = fp->insnsi[i];

176 if (!was_ld_map &&

177 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&

178 dst[i].src_reg == BPF_PSEUDO_MAP_FD) {

179 was_ld_map = true;

180 dst[i].imm = 0;

181 } else if (was_ld_map &&

182 dst[i].code == 0 &&

183 dst[i].dst_reg == 0 &&

184 dst[i].src_reg == 0 &&

185 dst[i].off == 0) {

186 was_ld_map = false;

187 dst[i].imm = 0;

188 } else {

189 was_ld_map = false;

190 }

191 }

192

193 psize = bpf_prog_insn_size(fp);

194 memset(&raw[psize], 0, raw_size - psize);

195 raw[psize++] = 0x80;

196

197 bsize = round_up(psize, SHA_MESSAGE_BYTES);

198 blocks = bsize / SHA_MESSAGE_BYTES;

199 todo = raw;

200 if (bsize - psize >= sizeof(__be64)) {

201 bits = (__be64 *)(todo + bsize - sizeof(__be64));

202 } else {

203 bits = (__be64 *)(todo + bsize + bits_offset);

204 blocks++;

205 }

206 *bits = cpu_to_be64((psize - 1) << 3);

207

208 while (blocks--) {

209 sha_transform(digest, todo, ws);

210 todo += SHA_MESSAGE_BYTES;

211 }

212

213 result = (__force __be32 *)digest;

214 for (i = 0; i < SHA_DIGEST_WORDS; i++)

215 result[i] = cpu_to_be32(digest[i]);

216 memcpy(fp->tag, result, sizeof(fp->tag));

217

218 vfree(raw);

219 return 0;

220 }

221

222 static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)

223 {

224 struct bpf_insn *insn = prog->insnsi;

225 u32 i, insn_cnt = prog->len;

226 bool pseudo_call;

227 u8 code;

228 int off;

229

230 for (i = 0; i < insn_cnt; i++, insn++) {

231 code = insn->code;

232 if (BPF_CLASS(code) != BPF_JMP)

233 continue;

234 if (BPF_OP(code) == BPF_EXIT)

235 continue;

236 if (BPF_OP(code) == BPF_CALL) {

237 if (insn->src_reg == BPF_PSEUDO_CALL)

238 pseudo_call = true;

239 else

240 continue;

241 } else {

242 pseudo_call = false;

243 }

244 off = pseudo_call ? insn->imm : insn->off;

245

246 /* Adjust offset of jmps if we cross boundaries. */

247 if (i < pos && i + off + 1 > pos)

248 off += delta;

249 else if (i > pos + delta && i + off + 1 <= pos + delta)

250 off -= delta;

251

252 if (pseudo_call)

253 insn->imm = off;

254 else

255 insn->off = off;

256 }

257 }

258

259 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,

260 const struct bpf_insn *patch, u32 len)

261 {

262 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;

263 struct bpf_prog *prog_adj;

264

265 /* Since our patchlet doesn't expand the image, we're done. */

266 if (insn_delta == 0) {

267 memcpy(prog->insnsi + off, patch, sizeof(*patch));

268 return prog;

269 }

270

271 insn_adj_cnt = prog->len + insn_delta;

272

273 /* Several new instructions need to be inserted. Make room

274 * for them. Likely, there's no need for a new allocation as

275 * last page could have large enough tailroom.

276 */

277 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),

278 GFP_USER);

279 if (!prog_adj)

280 return NULL;

281

282 prog_adj->len = insn_adj_cnt;

283

284 /* Patching happens in 3 steps:

285 *

286 * 1) Move over tail of insnsi from next instruction onwards,

287 * so we can patch the single target insn with one or more

288 * new ones (patching is always from 1 to n insns, n > 0).

289 * 2) Inject new instructions at the target location.

290 * 3) Adjust branch offsets if necessary.

291 */

292 insn_rest = insn_adj_cnt - off - len;

293

294 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,

295 sizeof(*patch) * insn_rest);

296 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);

297

298 bpf_adj_branches(prog_adj, off, insn_delta);

299

300 return prog_adj;

301 }

302

303 #ifdef CONFIG_BPF_JIT

304 /* All BPF JIT sysctl knobs here. */

305 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON);

306 int bpf_jit_harden __read_mostly;

307 int bpf_jit_kallsyms __read_mostly;

308

309 static __always_inline void

310 bpf_get_prog_addr_region(const struct bpf_prog *prog,

311 unsigned long *symbol_start,

312 unsigned long *symbol_end)

313 {

314 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);

315 unsigned long addr = (unsigned long)hdr;

316

317 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));

318

319 *symbol_start = addr;

320 *symbol_end = addr + hdr->pages * PAGE_SIZE;

321 }

322

323 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)

324 {

325 const char *end = sym + KSYM_NAME_LEN;

326

327 BUILD_BUG_ON(sizeof("bpf_prog_") +

328 sizeof(prog->tag) * 2 +

329 /* name has been null terminated.

330 * We should need +1 for the '_' preceding

331 * the name. However, the null character

332 * is double counted between the name and the

333 * sizeof("bpf_prog_") above, so we omit

334 * the +1 here.

335 */

336 sizeof(prog->aux->name) > KSYM_NAME_LEN);

337

338 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");

339 sym = bin2hex(sym, prog->tag, sizeof(prog->tag));

340 if (prog->aux->name[0])

341 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);

342 else

343 *sym = 0;

344 }

345

346 static __always_inline unsigned long

347 bpf_get_prog_addr_start(struct latch_tree_node *n)

348 {

349 unsigned long symbol_start, symbol_end;

350 const struct bpf_prog_aux *aux;

351

352 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);

353 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);

354

355 return symbol_start;

356 }

357

358 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,

359 struct latch_tree_node *b)

360 {

361 return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);

362 }

363

364 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)

365 {

366 unsigned long val = (unsigned long)key;

367 unsigned long symbol_start, symbol_end;

368 const struct bpf_prog_aux *aux;

369

370 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);

371 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);

372

373 if (val < symbol_start)

374 return -1;

375 if (val >= symbol_end)

376 return 1;

377

378 return 0;

379 }

380

381 static const struct latch_tree_ops bpf_tree_ops = {

382 .less = bpf_tree_less,

383 .comp = bpf_tree_comp,

384 };

385

386 static DEFINE_SPINLOCK(bpf_lock);

387 static LIST_HEAD(bpf_kallsyms);

388 static struct latch_tree_root bpf_tree __cacheline_aligned;

389

390 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)

391 {

392 WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));

393 list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);

394 latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);

395 }

396

397 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)

398 {

399 if (list_empty(&aux->ksym_lnode))

400 return;

401

402 latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);

403 list_del_rcu(&aux->ksym_lnode);

404 }

405

406 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)

407 {

408 return fp->jited && !bpf_prog_was_classic(fp);

409 }

410

411 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)

412 {

413 return list_empty(&fp->aux->ksym_lnode) ||

414 fp->aux->ksym_lnode.prev == LIST_POISON2;

415 }

416

417 void bpf_prog_kallsyms_add(struct bpf_prog *fp)

418 {

419 if (!bpf_prog_kallsyms_candidate(fp) ||

420 !capable(CAP_SYS_ADMIN))

421 return;

422

423 spin_lock_bh(&bpf_lock);

424 bpf_prog_ksym_node_add(fp->aux);

425 spin_unlock_bh(&bpf_lock);

426 }

427

428 void bpf_prog_kallsyms_del(struct bpf_prog *fp)

429 {

430 if (!bpf_prog_kallsyms_candidate(fp))

431 return;

432

433 spin_lock_bh(&bpf_lock);

434 bpf_prog_ksym_node_del(fp->aux);

435 spin_unlock_bh(&bpf_lock);

436 }

437

438 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)

439 {

440 struct latch_tree_node *n;

441

442 if (!bpf_jit_kallsyms_enabled())

443 return NULL;

444

445 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);

446 return n ?

447 container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :

448 NULL;

449 }

450

451 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,

452 unsigned long *off, char *sym)

453 {

454 unsigned long symbol_start, symbol_end;

455 struct bpf_prog *prog;

456 char *ret = NULL;

457

458 rcu_read_lock();

459 prog = bpf_prog_kallsyms_find(addr);

460 if (prog) {

461 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);

462 bpf_get_prog_name(prog, sym);

463

464 ret = sym;

465 if (size)

466 *size = symbol_end - symbol_start;

467 if (off)

468 *off = addr - symbol_start;

469 }

470 rcu_read_unlock();

471

472 return ret;

473 }

474

475 bool is_bpf_text_address(unsigned long addr)

476 {

477 bool ret;

478

479 rcu_read_lock();

480 ret = bpf_prog_kallsyms_find(addr) != NULL;

481 rcu_read_unlock();

482

483 return ret;

484 }

485

486 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,

487 char *sym)

488 {

489 unsigned long symbol_start, symbol_end;

490 struct bpf_prog_aux *aux;

491 unsigned int it = 0;

492 int ret = -ERANGE;

493

494 if (!bpf_jit_kallsyms_enabled())

495 return ret;

496

497 rcu_read_lock();

498 list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {

499 if (it++ != symnum)

500 continue;

501

502 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);

503 bpf_get_prog_name(aux->prog, sym);

504

505 *value = symbol_start;

506 *type = BPF_SYM_ELF_TYPE;

507

508 ret = 0;

509 break;

510 }

511 rcu_read_unlock();

512

513 return ret;

514 }

515

516 struct bpf_binary_header *

517 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,

518 unsigned int alignment,

519 bpf_jit_fill_hole_t bpf_fill_ill_insns)

520 {

521 struct bpf_binary_header *hdr;

522 unsigned int size, hole, start;

523

524 /* Most of BPF filters are really small, but if some of them

525 * fill a page, allow at least 128 extra bytes to insert a

526 * random section of illegal instructions.

527 */

528 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);

529 hdr = module_alloc(size);

530 if (hdr == NULL)

531 return NULL;

532

533 /* Fill space with illegal/arch-dep instructions. */

534 bpf_fill_ill_insns(hdr, size);

535

536 hdr->pages = size / PAGE_SIZE;

537 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),

538 PAGE_SIZE - sizeof(*hdr));

539 start = (get_random_int() % hole) & ~(alignment - 1);

540

541 /* Leave a random number of instructions before BPF code. */

542 *image_ptr = &hdr->image[start];

543

544 return hdr;

545 }

546

547 void bpf_jit_binary_free(struct bpf_binary_header *hdr)

548 {

549 module_memfree(hdr);

550 }

551

552 /* This symbol is only overridden by archs that have different

553 * requirements than the usual eBPF JITs, f.e. when they only

554 * implement cBPF JIT, do not set images read-only, etc.

555 */

556 void __weak bpf_jit_free(struct bpf_prog *fp)

557 {

558 if (fp->jited) {

559 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);

560

561 bpf_jit_binary_unlock_ro(hdr);

562 bpf_jit_binary_free(hdr);

563

564 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));

565 }

566

567 bpf_prog_unlock_free(fp);

568 }

569

570 static int bpf_jit_blind_insn(const struct bpf_insn *from,

571 const struct bpf_insn *aux,

572 struct bpf_insn *to_buff)

573 {

574 struct bpf_insn *to = to_buff;

575 u32 imm_rnd = get_random_int();

576 s16 off;

577

578 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);

579 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);

580

581 if (from->imm == 0 &&

582 (from->code == (BPF_ALU | BPF_MOV | BPF_K) ||

583 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {

584 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);

585 goto out;

586 }

587

588 switch (from->code) {

589 case BPF_ALU | BPF_ADD | BPF_K:

590 case BPF_ALU | BPF_SUB | BPF_K:

591 case BPF_ALU | BPF_AND | BPF_K:

592 case BPF_ALU | BPF_OR | BPF_K:

593 case BPF_ALU | BPF_XOR | BPF_K:

594 case BPF_ALU | BPF_MUL | BPF_K:

595 case BPF_ALU | BPF_MOV | BPF_K:

596 case BPF_ALU | BPF_DIV | BPF_K:

597 case BPF_ALU | BPF_MOD | BPF_K:

598 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);

599 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);

600 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);

601 break;

602

603 case BPF_ALU64 | BPF_ADD | BPF_K:

604 case BPF_ALU64 | BPF_SUB | BPF_K:

605 case BPF_ALU64 | BPF_AND | BPF_K:

606 case BPF_ALU64 | BPF_OR | BPF_K:

607 case BPF_ALU64 | BPF_XOR | BPF_K:

608 case BPF_ALU64 | BPF_MUL | BPF_K:

609 case BPF_ALU64 | BPF_MOV | BPF_K:

610 case BPF_ALU64 | BPF_DIV | BPF_K:

611 case BPF_ALU64 | BPF_MOD | BPF_K:

612 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);

613 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);

614 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);

615 break;

616

617 case BPF_JMP | BPF_JEQ | BPF_K:

618 case BPF_JMP | BPF_JNE | BPF_K:

619 case BPF_JMP | BPF_JGT | BPF_K:

620 case BPF_JMP | BPF_JLT | BPF_K:

621 case BPF_JMP | BPF_JGE | BPF_K:

622 case BPF_JMP | BPF_JLE | BPF_K:

623 case BPF_JMP | BPF_JSGT | BPF_K:

624 case BPF_JMP | BPF_JSLT | BPF_K:

625 case BPF_JMP | BPF_JSGE | BPF_K:

626 case BPF_JMP | BPF_JSLE | BPF_K:

627 case BPF_JMP | BPF_JSET | BPF_K:

628 /* Accommodate for extra offset in case of a backjump. */

629 off = from->off;

630 if (off < 0)

631 off -= 2;

632 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);

633 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);

634 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);

635 break;

636

637 case BPF_LD | BPF_IMM | BPF_DW:

638 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);

639 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);

640 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);

641 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);

642 break;

643 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */

644 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);

645 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);

646 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);

647 break;

648

649 case BPF_ST | BPF_MEM | BPF_DW:

650 case BPF_ST | BPF_MEM | BPF_W:

651 case BPF_ST | BPF_MEM | BPF_H:

652 case BPF_ST | BPF_MEM | BPF_B:

653 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);

654 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);

655 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);

656 break;

657 }

658 out:

659 return to - to_buff;

660 }

661

662 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,

663 gfp_t gfp_extra_flags)

664 {

665 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;

666 struct bpf_prog *fp;

667

668 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);

669 if (fp != NULL) {

670 /* aux->prog still points to the fp_other one, so

671 * when promoting the clone to the real program,

672 * this still needs to be adapted.

673 */

674 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);

675 }

676

677 return fp;

678 }

679

680 static void bpf_prog_clone_free(struct bpf_prog *fp)

681 {

682 /* aux was stolen by the other clone, so we cannot free

683 * it from this path! It will be freed eventually by the

684 * other program on release.

685 *

686 * At this point, we don't need a deferred release since

687 * clone is guaranteed to not be locked.

688 */

689 fp->aux = NULL;

690 __bpf_prog_free(fp);

691 }

692

693 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)

694 {

695 /* We have to repoint aux->prog to self, as we don't

696 * know whether fp here is the clone or the original.

697 */

698 fp->aux->prog = fp;

699 bpf_prog_clone_free(fp_other);

700 }

701

702 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)

703 {

704 struct bpf_insn insn_buff[16], aux[2];

705 struct bpf_prog *clone, *tmp;

706 int insn_delta, insn_cnt;

707 struct bpf_insn *insn;

708 int i, rewritten;

709

710 if (!bpf_jit_blinding_enabled(prog) || prog->blinded)

711 return prog;

712

713 clone = bpf_prog_clone_create(prog, GFP_USER);

714 if (!clone)

715 return ERR_PTR(-ENOMEM);

716

717 insn_cnt = clone->len;

718 insn = clone->insnsi;

719

720 for (i = 0; i < insn_cnt; i++, insn++) {

721 /* We temporarily need to hold the original ld64 insn

722 * so that we can still access the first part in the

723 * second blinding run.

724 */

725 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&

726 insn[1].code == 0)

727 memcpy(aux, insn, sizeof(aux));

728

729 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);

730 if (!rewritten)

731 continue;

732

733 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);

734 if (!tmp) {

735 /* Patching may have repointed aux->prog during

736 * realloc from the original one, so we need to

737 * fix it up here on error.

738 */

739 bpf_jit_prog_release_other(prog, clone);

740 return ERR_PTR(-ENOMEM);

741 }

742

743 clone = tmp;

744 insn_delta = rewritten - 1;

745

746 /* Walk new program and skip insns we just inserted. */

747 insn = clone->insnsi + i + insn_delta;

748 insn_cnt += insn_delta;

749 i += insn_delta;

750 }

751

752 clone->blinded = 1;

753 return clone;

754 }

755 #endif /* CONFIG_BPF_JIT */

756

757 /* Base function for offset calculation. Needs to go into .text section,

758 * therefore keeping it non-static as well; will also be used by JITs

759 * anyway later on, so do not let the compiler omit it. This also needs

760 * to go into kallsyms for correlation from e.g. bpftool, so naming

761 * must not change.

762 */

763 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)

764 {

765 return 0;

766 }

767 EXPORT_SYMBOL_GPL(__bpf_call_base);

768

769 /* All UAPI available opcodes. */

770 #define BPF_INSN_MAP(INSN_2, INSN_3) \

771 /* 32 bit ALU operations. */ \

772 /* Register based. */ \

773 INSN_3(ALU, ADD, X), \

774 INSN_3(ALU, SUB, X), \

775 INSN_3(ALU, AND, X), \

776 INSN_3(ALU, OR, X), \

777 INSN_3(ALU, LSH, X), \

778 INSN_3(ALU, RSH, X), \

779 INSN_3(ALU, XOR, X), \

780 INSN_3(ALU, MUL, X), \

781 INSN_3(ALU, MOV, X), \

782 INSN_3(ALU, DIV, X), \

783 INSN_3(ALU, MOD, X), \

784 INSN_2(ALU, NEG), \

785 INSN_3(ALU, END, TO_BE), \

786 INSN_3(ALU, END, TO_LE), \

787 /* Immediate based. */ \

788 INSN_3(ALU, ADD, K), \

789 INSN_3(ALU, SUB, K), \

790 INSN_3(ALU, AND, K), \

791 INSN_3(ALU, OR, K), \

792 INSN_3(ALU, LSH, K), \

793 INSN_3(ALU, RSH, K), \

794 INSN_3(ALU, XOR, K), \

795 INSN_3(ALU, MUL, K), \

796 INSN_3(ALU, MOV, K), \

797 INSN_3(ALU, DIV, K), \

798 INSN_3(ALU, MOD, K), \

799 /* 64 bit ALU operations. */ \

800 /* Register based. */ \

801 INSN_3(ALU64, ADD, X), \

802 INSN_3(ALU64, SUB, X), \

803 INSN_3(ALU64, AND, X), \

804 INSN_3(ALU64, OR, X), \

805 INSN_3(ALU64, LSH, X), \

806 INSN_3(ALU64, RSH, X), \

807 INSN_3(ALU64, XOR, X), \

808 INSN_3(ALU64, MUL, X), \

809 INSN_3(ALU64, MOV, X), \

810 INSN_3(ALU64, ARSH, X), \

811 INSN_3(ALU64, DIV, X), \

812 INSN_3(ALU64, MOD, X), \

813 INSN_2(ALU64, NEG), \

814 /* Immediate based. */ \

815 INSN_3(ALU64, ADD, K), \

816 INSN_3(ALU64, SUB, K), \

817 INSN_3(ALU64, AND, K), \

818 INSN_3(ALU64, OR, K), \

819 INSN_3(ALU64, LSH, K), \

820 INSN_3(ALU64, RSH, K), \

821 INSN_3(ALU64, XOR, K), \

822 INSN_3(ALU64, MUL, K), \

823 INSN_3(ALU64, MOV, K), \

824 INSN_3(ALU64, ARSH, K), \

825 INSN_3(ALU64, DIV, K), \

826 INSN_3(ALU64, MOD, K), \

827 /* Call instruction. */ \

828 INSN_2(JMP, CALL), \

829 /* Exit instruction. */ \

830 INSN_2(JMP, EXIT), \

831 /* Jump instructions. */ \

832 /* Register based. */ \

833 INSN_3(JMP, JEQ, X), \

834 INSN_3(JMP, JNE, X), \

835 INSN_3(JMP, JGT, X), \

836 INSN_3(JMP, JLT, X), \

837 INSN_3(JMP, JGE, X), \

838 INSN_3(JMP, JLE, X), \

839 INSN_3(JMP, JSGT, X), \

840 INSN_3(JMP, JSLT, X), \

841 INSN_3(JMP, JSGE, X), \

842 INSN_3(JMP, JSLE, X), \

843 INSN_3(JMP, JSET, X), \

844 /* Immediate based. */ \

845 INSN_3(JMP, JEQ, K), \

846 INSN_3(JMP, JNE, K), \

847 INSN_3(JMP, JGT, K), \

848 INSN_3(JMP, JLT, K), \

849 INSN_3(JMP, JGE, K), \

850 INSN_3(JMP, JLE, K), \

851 INSN_3(JMP, JSGT, K), \

852 INSN_3(JMP, JSLT, K), \

853 INSN_3(JMP, JSGE, K), \

854 INSN_3(JMP, JSLE, K), \

855 INSN_3(JMP, JSET, K), \

856 INSN_2(JMP, JA), \

857 /* Store instructions. */ \

858 /* Register based. */ \

859 INSN_3(STX, MEM, B), \

860 INSN_3(STX, MEM, H), \

861 INSN_3(STX, MEM, W), \

862 INSN_3(STX, MEM, DW), \

863 INSN_3(STX, XADD, W), \

864 INSN_3(STX, XADD, DW), \

865 /* Immediate based. */ \

866 INSN_3(ST, MEM, B), \

867 INSN_3(ST, MEM, H), \

868 INSN_3(ST, MEM, W), \

869 INSN_3(ST, MEM, DW), \

870 /* Load instructions. */ \

871 /* Register based. */ \

872 INSN_3(LDX, MEM, B), \

873 INSN_3(LDX, MEM, H), \

874 INSN_3(LDX, MEM, W), \

875 INSN_3(LDX, MEM, DW), \

876 /* Immediate based. */ \

877 INSN_3(LD, IMM, DW)

878

879 bool bpf_opcode_in_insntable(u8 code)

880 {

881 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true

882 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true

883 static const bool public_insntable[256] = {

884 [0 ... 255] = false,

885 /* Now overwrite non-defaults ... */

886 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),

887 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */

888 [BPF_LD | BPF_ABS | BPF_B] = true,

889 [BPF_LD | BPF_ABS | BPF_H] = true,

890 [BPF_LD | BPF_ABS | BPF_W] = true,

891 [BPF_LD | BPF_IND | BPF_B] = true,

892 [BPF_LD | BPF_IND | BPF_H] = true,

893 [BPF_LD | BPF_IND | BPF_W] = true,

894 };

895 #undef BPF_INSN_3_TBL

896 #undef BPF_INSN_2_TBL

897 return public_insntable[code];

898 }

899

900 #ifndef CONFIG_BPF_JIT_ALWAYS_ON

901 /**

902 * __bpf_prog_run - run eBPF program on a given context

903 * @ctx: is the data we are operating on

904 * @insn: is the array of eBPF instructions

905 *

906 * Decode and execute eBPF instructions.

907 */

908 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)

909 {

910 u64 tmp;

911 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y

912 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z

913 static const void *jumptable[256] = {

914 [0 ... 255] = &&default_label,

915 /* Now overwrite non-defaults ... */

916 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),

917 /* Non-UAPI available opcodes. */

918 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,

919 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,

920 };

921 #undef BPF_INSN_3_LBL

922 #undef BPF_INSN_2_LBL

923 u32 tail_call_cnt = 0;

924

925 #define CONT ({ insn++; goto select_insn; })

926 #define CONT_JMP ({ insn++; goto select_insn; })

927

928 select_insn:

929 goto *jumptable[insn->code];

930

931 /* ALU */

932 #define ALU(OPCODE, OP) \

933 ALU64_##OPCODE##_X: \

934 DST = DST OP SRC; \

935 CONT; \

936 ALU_##OPCODE##_X: \

937 DST = (u32) DST OP (u32) SRC; \

938 CONT; \

939 ALU64_##OPCODE##_K: \

940 DST = DST OP IMM; \

941 CONT; \

942 ALU_##OPCODE##_K: \

943 DST = (u32) DST OP (u32) IMM; \

944 CONT;

945

946 ALU(ADD, +)

947 ALU(SUB, -)

948 ALU(AND, &)

949 ALU(OR, |)

950 ALU(LSH, <<)

951 ALU(RSH, >>)

952 ALU(XOR, ^)

953 ALU(MUL, *)

954 #undef ALU

955 ALU_NEG:

956 DST = (u32) -DST;

957 CONT;

958 ALU64_NEG:

959 DST = -DST;

960 CONT;

961 ALU_MOV_X:

962 DST = (u32) SRC;

963 CONT;

964 ALU_MOV_K:

965 DST = (u32) IMM;

966 CONT;

967 ALU64_MOV_X:

968 DST = SRC;

969 CONT;

970 ALU64_MOV_K:

971 DST = IMM;

972 CONT;

973 LD_IMM_DW:

974 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;

975 insn++;

976 CONT;

977 ALU64_ARSH_X:

978 (*(s64 *) &DST) >>= SRC;

979 CONT;

980 ALU64_ARSH_K:

981 (*(s64 *) &DST) >>= IMM;

982 CONT;

983 ALU64_MOD_X:

984 div64_u64_rem(DST, SRC, &tmp);

985 DST = tmp;

986 CONT;

987 ALU_MOD_X:

988 tmp = (u32) DST;

989 DST = do_div(tmp, (u32) SRC);

990 CONT;

991 ALU64_MOD_K:

992 div64_u64_rem(DST, IMM, &tmp);

993 DST = tmp;

994 CONT;

995 ALU_MOD_K:

996 tmp = (u32) DST;

997 DST = do_div(tmp, (u32) IMM);

998 CONT;

999 ALU64_DIV_X:

1000 DST = div64_u64(DST, SRC);

1001 CONT;

1002 ALU_DIV_X:

1003 tmp = (u32) DST;

1004 do_div(tmp, (u32) SRC);

1005 DST = (u32) tmp;

1006 CONT;

1007 ALU64_DIV_K:

1008 DST = div64_u64(DST, IMM);

1009 CONT;

1010 ALU_DIV_K:

1011 tmp = (u32) DST;

1012 do_div(tmp, (u32) IMM);

1013 DST = (u32) tmp;

1014 CONT;

1015 ALU_END_TO_BE:

1016 switch (IMM) {

1017 case 16:

1018 DST = (__force u16) cpu_to_be16(DST);

1019 break;

1020 case 32:

1021 DST = (__force u32) cpu_to_be32(DST);

1022 break;

1023 case 64:

1024 DST = (__force u64) cpu_to_be64(DST);

1025 break;

1026 }

1027 CONT;

1028 ALU_END_TO_LE:

1029 switch (IMM) {

1030 case 16:

1031 DST = (__force u16) cpu_to_le16(DST);

1032 break;

1033 case 32:

1034 DST = (__force u32) cpu_to_le32(DST);

1035 break;

1036 case 64:

1037 DST = (__force u64) cpu_to_le64(DST);

1038 break;

1039 }

1040 CONT;

1041

1042 /* CALL */

1043 JMP_CALL:

1044 /* Function call scratches BPF_R1-BPF_R5 registers,

1045 * preserves BPF_R6-BPF_R9, and stores return value

1046 * into BPF_R0.

1047 */

1048 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,

1049 BPF_R4, BPF_R5);

1050 CONT;

1051

1052 JMP_CALL_ARGS:

1053 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,

1054 BPF_R3, BPF_R4,

1055 BPF_R5,

1056 insn + insn->off + 1);

1057 CONT;

1058

1059 JMP_TAIL_CALL: {

1060 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;

1061 struct bpf_array *array = container_of(map, struct bpf_array, map);

1062 struct bpf_prog *prog;

1063 u32 index = BPF_R3;

1064

1065 if (unlikely(index >= array->map.max_entries))

1066 goto out;

1067 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))

1068 goto out;

1069

1070 tail_call_cnt++;

1071

1072 prog = READ_ONCE(array->ptrs[index]);

1073 if (!prog)

1074 goto out;

1075

1076 /* ARG1 at this point is guaranteed to point to CTX from

1077 * the verifier side due to the fact that the tail call is

1078 * handeled like a helper, that is, bpf_tail_call_proto,

1079 * where arg1_type is ARG_PTR_TO_CTX.

1080 */

1081 insn = prog->insnsi;

1082 goto select_insn;

1083 out:

1084 CONT;

1085 }

1086 /* JMP */

1087 JMP_JA:

1088 insn += insn->off;

1089 CONT;

1090 JMP_JEQ_X:

1091 if (DST == SRC) {

1092 insn += insn->off;

1093 CONT_JMP;

1094 }

1095 CONT;

1096 JMP_JEQ_K:

1097 if (DST == IMM) {

1098 insn += insn->off;

1099 CONT_JMP;

1100 }

1101 CONT;

1102 JMP_JNE_X:

1103 if (DST != SRC) {

1104 insn += insn->off;

1105 CONT_JMP;

1106 }

1107 CONT;

1108 JMP_JNE_K:

1109 if (DST != IMM) {

1110 insn += insn->off;

1111 CONT_JMP;

1112 }

1113 CONT;

1114 JMP_JGT_X:

1115 if (DST > SRC) {

1116 insn += insn->off;

1117 CONT_JMP;

1118 }

1119 CONT;

1120 JMP_JGT_K:

1121 if (DST > IMM) {

1122 insn += insn->off;

1123 CONT_JMP;

1124 }

1125 CONT;

1126 JMP_JLT_X:

1127 if (DST < SRC) {

1128 insn += insn->off;

1129 CONT_JMP;

1130 }

1131 CONT;

1132 JMP_JLT_K:

1133 if (DST < IMM) {

1134 insn += insn->off;

1135 CONT_JMP;

1136 }

1137 CONT;

1138 JMP_JGE_X:

1139 if (DST >= SRC) {

1140 insn += insn->off;

1141 CONT_JMP;

1142 }

1143 CONT;

1144 JMP_JGE_K:

1145 if (DST >= IMM) {

1146 insn += insn->off;

1147 CONT_JMP;

1148 }

1149 CONT;

1150 JMP_JLE_X:

1151 if (DST <= SRC) {

1152 insn += insn->off;

1153 CONT_JMP;

1154 }

1155 CONT;

1156 JMP_JLE_K:

1157 if (DST <= IMM) {

1158 insn += insn->off;

1159 CONT_JMP;

1160 }

1161 CONT;

1162 JMP_JSGT_X:

1163 if (((s64) DST) > ((s64) SRC)) {

1164 insn += insn->off;

1165 CONT_JMP;

1166 }

1167 CONT;

1168 JMP_JSGT_K:

1169 if (((s64) DST) > ((s64) IMM)) {

1170 insn += insn->off;

1171 CONT_JMP;

1172 }

1173 CONT;

1174 JMP_JSLT_X:

1175 if (((s64) DST) < ((s64) SRC)) {

1176 insn += insn->off;

1177 CONT_JMP;

1178 }

1179 CONT;

1180 JMP_JSLT_K:

1181 if (((s64) DST) < ((s64) IMM)) {

1182 insn += insn->off;

1183 CONT_JMP;

1184 }

1185 CONT;

1186 JMP_JSGE_X:

1187 if (((s64) DST) >= ((s64) SRC)) {

1188 insn += insn->off;

1189 CONT_JMP;

1190 }

1191 CONT;

1192 JMP_JSGE_K:

1193 if (((s64) DST) >= ((s64) IMM)) {

1194 insn += insn->off;

1195 CONT_JMP;

1196 }

1197 CONT;

1198 JMP_JSLE_X:

1199 if (((s64) DST) <= ((s64) SRC)) {

1200 insn += insn->off;

1201 CONT_JMP;

1202 }

1203 CONT;

1204 JMP_JSLE_K:

1205 if (((s64) DST) <= ((s64) IMM)) {

1206 insn += insn->off;

1207 CONT_JMP;

1208 }

1209 CONT;

1210 JMP_JSET_X:

1211 if (DST & SRC) {

1212 insn += insn->off;

1213 CONT_JMP;

1214 }

1215 CONT;

1216 JMP_JSET_K:

1217 if (DST & IMM) {

1218 insn += insn->off;

1219 CONT_JMP;

1220 }

1221 CONT;

1222 JMP_EXIT:

1223 return BPF_R0;

1224

1225 /* STX and ST and LDX*/

1226 #define LDST(SIZEOP, SIZE) \

1227 STX_MEM_##SIZEOP: \

1228 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \

1229 CONT; \

1230 ST_MEM_##SIZEOP: \

1231 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \

1232 CONT; \

1233 LDX_MEM_##SIZEOP: \

1234 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \

1235 CONT;

1236

1237 LDST(B, u8)

1238 LDST(H, u16)

1239 LDST(W, u32)

1240 LDST(DW, u64)

1241 #undef LDST

1242 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */

1243 atomic_add((u32) SRC, (atomic_t *)(unsigned long)

1244 (DST + insn->off));

1245 CONT;

1246 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */

1247 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)

1248 (DST + insn->off));

1249 CONT;

1250

1251 default_label:

1252 /* If we ever reach this, we have a bug somewhere. Die hard here

1253 * instead of just returning 0; we could be somewhere in a subprog,

1254 * so execution could continue otherwise which we do /not/ want.

1255 *

1256 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().

1257 */

1258 pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code);

1259 BUG_ON(1);

1260 return 0;

1261 }

1262 STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */

1263

1264 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size

1265 #define DEFINE_BPF_PROG_RUN(stack_size) \

1266 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \

1267 { \

1268 u64 stack[stack_size / sizeof(u64)]; \

1269 u64 regs[MAX_BPF_REG]; \

1270 \

1271 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \

1272 ARG1 = (u64) (unsigned long) ctx; \

1273 return ___bpf_prog_run(regs, insn, stack); \

1274 }

1275

1276 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size

1277 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \

1278 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \

1279 const struct bpf_insn *insn) \

1280 { \

1281 u64 stack[stack_size / sizeof(u64)]; \

1282 u64 regs[MAX_BPF_REG]; \

1283 \

1284 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \

1285 BPF_R1 = r1; \

1286 BPF_R2 = r2; \

1287 BPF_R3 = r3; \

1288 BPF_R4 = r4; \

1289 BPF_R5 = r5; \

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 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);

1305 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);

1306 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);

1307

1308 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),

1309

1310 static unsigned int (*interpreters[])(const void *ctx,

1311 const struct bpf_insn *insn) = {

1312 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)

1313 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)

1314 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)

1315 };

1316 #undef PROG_NAME_LIST

1317 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),

1318 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,

1319 const struct bpf_insn *insn) = {

1320 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)

1321 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)

1322 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)

1323 };

1324 #undef PROG_NAME_LIST

1325

1326 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)

1327 {

1328 stack_depth = max_t(u32, stack_depth, 1);

1329 insn->off = (s16) insn->imm;

1330 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -

1331 __bpf_call_base_args;

1332 insn->code = BPF_JMP | BPF_CALL_ARGS;

1333 }

1334

1335 #else

1336 static unsigned int __bpf_prog_ret0_warn(const void *ctx,

1337 const struct bpf_insn *insn)

1338 {

1339 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON

1340 * is not working properly, so warn about it!

1341 */

1342 WARN_ON_ONCE(1);

1343 return 0;

1344 }

1345 #endif

1346

1347 bool bpf_prog_array_compatible(struct bpf_array *array,

1348 const struct bpf_prog *fp)

1349 {

1350 if (fp->kprobe_override)

1351 return false;

1352

1353 if (!array->owner_prog_type) {

1354 /* There's no owner yet where we could check for

1355 * compatibility.

1356 */

1357 array->owner_prog_type = fp->type;

1358 array->owner_jited = fp->jited;

1359

1360 return true;

1361 }

1362

1363 return array->owner_prog_type == fp->type &&

1364 array->owner_jited == fp->jited;

1365 }

1366

1367 static int bpf_check_tail_call(const struct bpf_prog *fp)

1368 {

1369 struct bpf_prog_aux *aux = fp->aux;

1370 int i;

1371

1372 for (i = 0; i < aux->used_map_cnt; i++) {

1373 struct bpf_map *map = aux->used_maps[i];

1374 struct bpf_array *array;

1375

1376 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)

1377 continue;

1378

1379 array = container_of(map, struct bpf_array, map);

1380 if (!bpf_prog_array_compatible(array, fp))

1381 return -EINVAL;

1382 }

1383

1384 return 0;

1385 }

1386

1387 /**

1388 * bpf_prog_select_runtime - select exec runtime for BPF program

1389 * @fp: bpf_prog populated with internal BPF program

1390 * @err: pointer to error variable

1391 *

1392 * Try to JIT eBPF program, if JIT is not available, use interpreter.

1393 * The BPF program will be executed via BPF_PROG_RUN() macro.

1394 */

1395 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)

1396 {

1397 #ifndef CONFIG_BPF_JIT_ALWAYS_ON

1398 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);

1399

1400 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];

1401 #else

1402 fp->bpf_func = __bpf_prog_ret0_warn;

1403 #endif

1404

1405 /* eBPF JITs can rewrite the program in case constant

1406 * blinding is active. However, in case of error during

1407 * blinding, bpf_int_jit_compile() must always return a

1408 * valid program, which in this case would simply not

1409 * be JITed, but falls back to the interpreter.

1410 */

1411 if (!bpf_prog_is_dev_bound(fp->aux)) {

1412 fp = bpf_int_jit_compile(fp);

1413 #ifdef CONFIG_BPF_JIT_ALWAYS_ON

1414 if (!fp->jited) {

1415 *err = -ENOTSUPP;

1416 return fp;

1417 }

1418 #endif

1419 } else {

1420 *err = bpf_prog_offload_compile(fp);

1421 if (*err)

1422 return fp;

1423 }

1424 bpf_prog_lock_ro(fp);

1425

1426 /* The tail call compatibility check can only be done at

1427 * this late stage as we need to determine, if we deal

1428 * with JITed or non JITed program concatenations and not

1429 * all eBPF JITs might immediately support all features.

1430 */

1431 *err = bpf_check_tail_call(fp);

1432

1433 return fp;

1434 }

1435 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);

1436

1437 static unsigned int __bpf_prog_ret1(const void *ctx,

1438 const struct bpf_insn *insn)

1439 {

1440 return 1;

1441 }

1442

1443 static struct bpf_prog_dummy {

1444 struct bpf_prog prog;

1445 } dummy_bpf_prog = {

1446 .prog = {

1447 .bpf_func = __bpf_prog_ret1,

1448 },

1449 };

1450

1451 /* to avoid allocating empty bpf_prog_array for cgroups that

1452 * don't have bpf program attached use one global 'empty_prog_array'

1453 * It will not be modified the caller of bpf_prog_array_alloc()

1454 * (since caller requested prog_cnt == 0)

1455 * that pointer should be 'freed' by bpf_prog_array_free()

1456 */

1457 static struct {

1458 struct bpf_prog_array hdr;

1459 struct bpf_prog *null_prog;

1460 } empty_prog_array = {

1461 .null_prog = NULL,

1462 };

1463

1464 struct bpf_prog_array __rcu *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)

1465 {

1466 if (prog_cnt)

1467 return kzalloc(sizeof(struct bpf_prog_array) +

1468 sizeof(struct bpf_prog *) * (prog_cnt + 1),

1469 flags);

1470

1471 return &empty_prog_array.hdr;

1472 }

1473

1474 void bpf_prog_array_free(struct bpf_prog_array __rcu *progs)

1475 {

1476 if (!progs ||

1477 progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr)

1478 return;

1479 kfree_rcu(progs, rcu);

1480 }

1481

1482 int bpf_prog_array_length(struct bpf_prog_array __rcu *progs)

1483 {

1484 struct bpf_prog **prog;

1485 u32 cnt = 0;

1486

1487 rcu_read_lock();

1488 prog = rcu_dereference(progs)->progs;

1489 for (; *prog; prog++)

1490 if (*prog != &dummy_bpf_prog.prog)

1491 cnt++;

1492 rcu_read_unlock();

1493 return cnt;

1494 }

1495

1496 static bool bpf_prog_array_copy_core(struct bpf_prog **prog,

1497 u32 *prog_ids,

1498 u32 request_cnt)

1499 {

1500 int i = 0;

1501

1502 for (; *prog; prog++) {

1503 if (*prog == &dummy_bpf_prog.prog)

1504 continue;

1505 prog_ids[i] = (*prog)->aux->id;

1506 if (++i == request_cnt) {

1507 prog++;

1508 break;

1509 }

1510 }

1511

1512 return !!(*prog);

1513 }

1514

1515 int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,

1516 __u32 __user *prog_ids, u32 cnt)

1517 {

1518 struct bpf_prog **prog;

1519 unsigned long err = 0;

1520 bool nospc;

1521 u32 *ids;

1522

1523 /* users of this function are doing:

1524 * cnt = bpf_prog_array_length();

1525 * if (cnt > 0)

1526 * bpf_prog_array_copy_to_user(..., cnt);

1527 * so below kcalloc doesn't need extra cnt > 0 check, but

1528 * bpf_prog_array_length() releases rcu lock and

1529 * prog array could have been swapped with empty or larger array,

1530 * so always copy 'cnt' prog_ids to the user.

1531 * In a rare race the user will see zero prog_ids

1532 */

1533 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);

1534 if (!ids)

1535 return -ENOMEM;

1536 rcu_read_lock();

1537 prog = rcu_dereference(progs)->progs;

1538 nospc = bpf_prog_array_copy_core(prog, ids, cnt);

1539 rcu_read_unlock();

1540 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));

1541 kfree(ids);

1542 if (err)

1543 return -EFAULT;

1544 if (nospc)

1545 return -ENOSPC;

1546 return 0;

1547 }

1548

1549 void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs,

1550 struct bpf_prog *old_prog)

1551 {

1552 struct bpf_prog **prog = progs->progs;

1553

1554 for (; *prog; prog++)

1555 if (*prog == old_prog) {

1556 WRITE_ONCE(*prog, &dummy_bpf_prog.prog);

1557 break;

1558 }

1559 }

1560

1561 int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,

1562 struct bpf_prog *exclude_prog,

1563 struct bpf_prog *include_prog,

1564 struct bpf_prog_array **new_array)

1565 {

1566 int new_prog_cnt, carry_prog_cnt = 0;

1567 struct bpf_prog **existing_prog;

1568 struct bpf_prog_array *array;

1569 int new_prog_idx = 0;

1570

1571 /* Figure out how many existing progs we need to carry over to

1572 * the new array.

1573 */

1574 if (old_array) {

1575 existing_prog = old_array->progs;

1576 for (; *existing_prog; existing_prog++) {

1577 if (*existing_prog != exclude_prog &&

1578 *existing_prog != &dummy_bpf_prog.prog)

1579 carry_prog_cnt++;

1580 if (*existing_prog == include_prog)

1581 return -EEXIST;

1582 }

1583 }

1584

1585 /* How many progs (not NULL) will be in the new array? */

1586 new_prog_cnt = carry_prog_cnt;

1587 if (include_prog)

1588 new_prog_cnt += 1;

1589

1590 /* Do we have any prog (not NULL) in the new array? */

1591 if (!new_prog_cnt) {

1592 *new_array = NULL;

1593 return 0;

1594 }

1595

1596 /* +1 as the end of prog_array is marked with NULL */

1597 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);

1598 if (!array)

1599 return -ENOMEM;

1600

1601 /* Fill in the new prog array */

1602 if (carry_prog_cnt) {

1603 existing_prog = old_array->progs;

1604 for (; *existing_prog; existing_prog++)

1605 if (*existing_prog != exclude_prog &&

1606 *existing_prog != &dummy_bpf_prog.prog)

1607 array->progs[new_prog_idx++] = *existing_prog;

1608 }

1609 if (include_prog)

1610 array->progs[new_prog_idx++] = include_prog;

1611 array->progs[new_prog_idx] = NULL;

1612 *new_array = array;

1613 return 0;

1614 }

1615

1616 int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array,

1617 u32 *prog_ids, u32 request_cnt,

1618 u32 *prog_cnt)

1619 {

1620 struct bpf_prog **prog;

1621 u32 cnt = 0;

1622

1623 if (array)

1624 cnt = bpf_prog_array_length(array);

1625

1626 *prog_cnt = cnt;

1627

1628 /* return early if user requested only program count or nothing to copy */

1629 if (!request_cnt || !cnt)

1630 return 0;

1631

1632 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */

1633 prog = rcu_dereference_check(array, 1)->progs;

1634 return bpf_prog_array_copy_core(prog, prog_ids, request_cnt) ? -ENOSPC

1635 : 0;

1636 }

1637

1638 static void bpf_prog_free_deferred(struct work_struct *work)

1639 {

1640 struct bpf_prog_aux *aux;

1641 int i;

1642

1643 aux = container_of(work, struct bpf_prog_aux, work);

1644 if (bpf_prog_is_dev_bound(aux))

1645 bpf_prog_offload_destroy(aux->prog);

1646 #ifdef CONFIG_PERF_EVENTS

1647 if (aux->prog->has_callchain_buf)

1648 put_callchain_buffers();

1649 #endif

1650 for (i = 0; i < aux->func_cnt; i++)

1651 bpf_jit_free(aux->func[i]);

1652 if (aux->func_cnt) {

1653 kfree(aux->func);

1654 bpf_prog_unlock_free(aux->prog);

1655 } else {

1656 bpf_jit_free(aux->prog);

1657 }

1658 }

1659

1660 /* Free internal BPF program */

1661 void bpf_prog_free(struct bpf_prog *fp)

1662 {

1663 struct bpf_prog_aux *aux = fp->aux;

1664

1665 INIT_WORK(&aux->work, bpf_prog_free_deferred);

1666 schedule_work(&aux->work);

1667 }

1668 EXPORT_SYMBOL_GPL(bpf_prog_free);

1669

1670 /* RNG for unpriviledged user space with separated state from prandom_u32(). */

1671 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);

1672

1673 void bpf_user_rnd_init_once(void)

1674 {

1675 prandom_init_once(&bpf_user_rnd_state);

1676 }

1677

1678 BPF_CALL_0(bpf_user_rnd_u32)

1679 {

1680 /* Should someone ever have the rather unwise idea to use some

1681 * of the registers passed into this function, then note that

1682 * this function is called from native eBPF and classic-to-eBPF

1683 * transformations. Register assignments from both sides are

1684 * different, f.e. classic always sets fn(ctx, A, X) here.

1685 */

1686 struct rnd_state *state;

1687 u32 res;

1688

1689 state = &get_cpu_var(bpf_user_rnd_state);

1690 res = prandom_u32_state(state);

1691 put_cpu_var(bpf_user_rnd_state);

1692

1693 return res;

1694 }

1695

1696 /* Weak definitions of helper functions in case we don't have bpf syscall. */

1697 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;

1698 const struct bpf_func_proto bpf_map_update_elem_proto __weak;

1699 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;

1700

1701 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;

1702 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;

1703 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;

1704 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;

1705

1706 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;

1707 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;

1708 const struct bpf_func_proto bpf_get_current_comm_proto __weak;

1709 const struct bpf_func_proto bpf_sock_map_update_proto __weak;

1710

1711 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)

1712 {

1713 return NULL;

1714 }

1715

1716 u64 __weak

1717 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,

1718 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)

1719 {

1720 return -ENOTSUPP;

1721 }

1722

1723 /* Always built-in helper functions. */

1724 const struct bpf_func_proto bpf_tail_call_proto = {

1725 .func = NULL,

1726 .gpl_only = false,

1727 .ret_type = RET_VOID,

1728 .arg1_type = ARG_PTR_TO_CTX,

1729 .arg2_type = ARG_CONST_MAP_PTR,

1730 .arg3_type = ARG_ANYTHING,

1731 };

1732

1733 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.

1734 * It is encouraged to implement bpf_int_jit_compile() instead, so that

1735 * eBPF and implicitly also cBPF can get JITed!

1736 */

1737 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)

1738 {

1739 return prog;

1740 }

1741

1742 /* Stub for JITs that support eBPF. All cBPF code gets transformed into

1743 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().

1744 */

1745 void __weak bpf_jit_compile(struct bpf_prog *prog)

1746 {

1747 }

1748

1749 bool __weak bpf_helper_changes_pkt_data(void *func)

1750 {

1751 return false;

1752 }

1753

1754 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call

1755 * skb_copy_bits(), so provide a weak definition of it for NET-less config.

1756 */

1757 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,

1758 int len)

1759 {

1760 return -EFAULT;

1761 }

1762

1763 /* All definitions of tracepoints related to BPF. */

1764 #define CREATE_TRACE_POINTS

1765 #include <linux/bpf_trace.h>

1766

1767 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);