1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux Socket Filter - Kernel level socket filtering 4 * 5 * Based on the design of the Berkeley Packet Filter. The new 6 * internal format has been designed by PLUMgrid: 7 * 8 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com 9 * 10 * Authors: 11 * 12 * Jay Schulist <jschlst@samba.org> 13 * Alexei Starovoitov <ast@plumgrid.com> 14 * Daniel Borkmann <dborkman@redhat.com> 15 * 16 * Andi Kleen - Fix a few bad bugs and races. 17 * Kris Katterjohn - Added many additional checks in bpf_check_classic() 18 */ 19 20 #include <uapi/linux/btf.h> 21 #include <linux/filter.h> 22 #include <linux/skbuff.h> 23 #include <linux/vmalloc.h> 24 #include <linux/random.h> 25 #include <linux/moduleloader.h> 26 #include <linux/bpf.h> 27 #include <linux/btf.h> 28 #include <linux/objtool.h> 29 #include <linux/rbtree_latch.h> 30 #include <linux/kallsyms.h> 31 #include <linux/rcupdate.h> 32 #include <linux/perf_event.h> 33 #include <linux/extable.h> 34 #include <linux/log2.h> 35 36 #include <asm/barrier.h> 37 #include <asm/unaligned.h> 38 39 /* Registers */ 40 #define BPF_R0 regs[BPF_REG_0] 41 #define BPF_R1 regs[BPF_REG_1] 42 #define BPF_R2 regs[BPF_REG_2] 43 #define BPF_R3 regs[BPF_REG_3] 44 #define BPF_R4 regs[BPF_REG_4] 45 #define BPF_R5 regs[BPF_REG_5] 46 #define BPF_R6 regs[BPF_REG_6] 47 #define BPF_R7 regs[BPF_REG_7] 48 #define BPF_R8 regs[BPF_REG_8] 49 #define BPF_R9 regs[BPF_REG_9] 50 #define BPF_R10 regs[BPF_REG_10] 51 52 /* Named registers */ 53 #define DST regs[insn->dst_reg] 54 #define SRC regs[insn->src_reg] 55 #define FP regs[BPF_REG_FP] 56 #define AX regs[BPF_REG_AX] 57 #define ARG1 regs[BPF_REG_ARG1] 58 #define CTX regs[BPF_REG_CTX] 59 #define IMM insn->imm 60 61 /* No hurry in this branch 62 * 63 * Exported for the bpf jit load helper. 64 */ 65 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 66 { 67 u8 *ptr = NULL; 68 69 if (k >= SKF_NET_OFF) 70 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 71 else if (k >= SKF_LL_OFF) 72 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 73 74 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 75 return ptr; 76 77 return NULL; 78 } 79 80 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 81 { 82 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 83 struct bpf_prog_aux *aux; 84 struct bpf_prog *fp; 85 86 size = round_up(size, PAGE_SIZE); 87 fp = __vmalloc(size, gfp_flags); 88 if (fp == NULL) 89 return NULL; 90 91 aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT | gfp_extra_flags); 92 if (aux == NULL) { 93 vfree(fp); 94 return NULL; 95 } 96 fp->active = alloc_percpu_gfp(int, GFP_KERNEL_ACCOUNT | gfp_extra_flags); 97 if (!fp->active) { 98 vfree(fp); 99 kfree(aux); 100 return NULL; 101 } 102 103 fp->pages = size / PAGE_SIZE; 104 fp->aux = aux; 105 fp->aux->prog = fp; 106 fp->jit_requested = ebpf_jit_enabled(); 107 108 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 109 mutex_init(&fp->aux->used_maps_mutex); 110 mutex_init(&fp->aux->dst_mutex); 111 112 return fp; 113 } 114 115 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 116 { 117 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 118 struct bpf_prog *prog; 119 int cpu; 120 121 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 122 if (!prog) 123 return NULL; 124 125 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 126 if (!prog->stats) { 127 free_percpu(prog->active); 128 kfree(prog->aux); 129 vfree(prog); 130 return NULL; 131 } 132 133 for_each_possible_cpu(cpu) { 134 struct bpf_prog_stats *pstats; 135 136 pstats = per_cpu_ptr(prog->stats, cpu); 137 u64_stats_init(&pstats->syncp); 138 } 139 return prog; 140 } 141 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 142 143 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 144 { 145 if (!prog->aux->nr_linfo || !prog->jit_requested) 146 return 0; 147 148 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 149 sizeof(*prog->aux->jited_linfo), 150 GFP_KERNEL_ACCOUNT | __GFP_NOWARN); 151 if (!prog->aux->jited_linfo) 152 return -ENOMEM; 153 154 return 0; 155 } 156 157 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 158 { 159 if (prog->aux->jited_linfo && 160 (!prog->jited || !prog->aux->jited_linfo[0])) { 161 kvfree(prog->aux->jited_linfo); 162 prog->aux->jited_linfo = NULL; 163 } 164 165 kfree(prog->aux->kfunc_tab); 166 prog->aux->kfunc_tab = NULL; 167 } 168 169 /* The jit engine is responsible to provide an array 170 * for insn_off to the jited_off mapping (insn_to_jit_off). 171 * 172 * The idx to this array is the insn_off. Hence, the insn_off 173 * here is relative to the prog itself instead of the main prog. 174 * This array has one entry for each xlated bpf insn. 175 * 176 * jited_off is the byte off to the last byte of the jited insn. 177 * 178 * Hence, with 179 * insn_start: 180 * The first bpf insn off of the prog. The insn off 181 * here is relative to the main prog. 182 * e.g. if prog is a subprog, insn_start > 0 183 * linfo_idx: 184 * The prog's idx to prog->aux->linfo and jited_linfo 185 * 186 * jited_linfo[linfo_idx] = prog->bpf_func 187 * 188 * For i > linfo_idx, 189 * 190 * jited_linfo[i] = prog->bpf_func + 191 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 192 */ 193 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 194 const u32 *insn_to_jit_off) 195 { 196 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 197 const struct bpf_line_info *linfo; 198 void **jited_linfo; 199 200 if (!prog->aux->jited_linfo) 201 /* Userspace did not provide linfo */ 202 return; 203 204 linfo_idx = prog->aux->linfo_idx; 205 linfo = &prog->aux->linfo[linfo_idx]; 206 insn_start = linfo[0].insn_off; 207 insn_end = insn_start + prog->len; 208 209 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 210 jited_linfo[0] = prog->bpf_func; 211 212 nr_linfo = prog->aux->nr_linfo - linfo_idx; 213 214 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 215 /* The verifier ensures that linfo[i].insn_off is 216 * strictly increasing 217 */ 218 jited_linfo[i] = prog->bpf_func + 219 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 220 } 221 222 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 223 gfp_t gfp_extra_flags) 224 { 225 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 226 struct bpf_prog *fp; 227 u32 pages; 228 229 size = round_up(size, PAGE_SIZE); 230 pages = size / PAGE_SIZE; 231 if (pages <= fp_old->pages) 232 return fp_old; 233 234 fp = __vmalloc(size, gfp_flags); 235 if (fp) { 236 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 237 fp->pages = pages; 238 fp->aux->prog = fp; 239 240 /* We keep fp->aux from fp_old around in the new 241 * reallocated structure. 242 */ 243 fp_old->aux = NULL; 244 fp_old->stats = NULL; 245 fp_old->active = NULL; 246 __bpf_prog_free(fp_old); 247 } 248 249 return fp; 250 } 251 252 void __bpf_prog_free(struct bpf_prog *fp) 253 { 254 if (fp->aux) { 255 mutex_destroy(&fp->aux->used_maps_mutex); 256 mutex_destroy(&fp->aux->dst_mutex); 257 kfree(fp->aux->poke_tab); 258 kfree(fp->aux); 259 } 260 free_percpu(fp->stats); 261 free_percpu(fp->active); 262 vfree(fp); 263 } 264 265 int bpf_prog_calc_tag(struct bpf_prog *fp) 266 { 267 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 268 u32 raw_size = bpf_prog_tag_scratch_size(fp); 269 u32 digest[SHA1_DIGEST_WORDS]; 270 u32 ws[SHA1_WORKSPACE_WORDS]; 271 u32 i, bsize, psize, blocks; 272 struct bpf_insn *dst; 273 bool was_ld_map; 274 u8 *raw, *todo; 275 __be32 *result; 276 __be64 *bits; 277 278 raw = vmalloc(raw_size); 279 if (!raw) 280 return -ENOMEM; 281 282 sha1_init(digest); 283 memset(ws, 0, sizeof(ws)); 284 285 /* We need to take out the map fd for the digest calculation 286 * since they are unstable from user space side. 287 */ 288 dst = (void *)raw; 289 for (i = 0, was_ld_map = false; i < fp->len; i++) { 290 dst[i] = fp->insnsi[i]; 291 if (!was_ld_map && 292 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 293 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 294 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 295 was_ld_map = true; 296 dst[i].imm = 0; 297 } else if (was_ld_map && 298 dst[i].code == 0 && 299 dst[i].dst_reg == 0 && 300 dst[i].src_reg == 0 && 301 dst[i].off == 0) { 302 was_ld_map = false; 303 dst[i].imm = 0; 304 } else { 305 was_ld_map = false; 306 } 307 } 308 309 psize = bpf_prog_insn_size(fp); 310 memset(&raw[psize], 0, raw_size - psize); 311 raw[psize++] = 0x80; 312 313 bsize = round_up(psize, SHA1_BLOCK_SIZE); 314 blocks = bsize / SHA1_BLOCK_SIZE; 315 todo = raw; 316 if (bsize - psize >= sizeof(__be64)) { 317 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 318 } else { 319 bits = (__be64 *)(todo + bsize + bits_offset); 320 blocks++; 321 } 322 *bits = cpu_to_be64((psize - 1) << 3); 323 324 while (blocks--) { 325 sha1_transform(digest, todo, ws); 326 todo += SHA1_BLOCK_SIZE; 327 } 328 329 result = (__force __be32 *)digest; 330 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 331 result[i] = cpu_to_be32(digest[i]); 332 memcpy(fp->tag, result, sizeof(fp->tag)); 333 334 vfree(raw); 335 return 0; 336 } 337 338 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 339 s32 end_new, s32 curr, const bool probe_pass) 340 { 341 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 342 s32 delta = end_new - end_old; 343 s64 imm = insn->imm; 344 345 if (curr < pos && curr + imm + 1 >= end_old) 346 imm += delta; 347 else if (curr >= end_new && curr + imm + 1 < end_new) 348 imm -= delta; 349 if (imm < imm_min || imm > imm_max) 350 return -ERANGE; 351 if (!probe_pass) 352 insn->imm = imm; 353 return 0; 354 } 355 356 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 357 s32 end_new, s32 curr, const bool probe_pass) 358 { 359 const s32 off_min = S16_MIN, off_max = S16_MAX; 360 s32 delta = end_new - end_old; 361 s32 off = insn->off; 362 363 if (curr < pos && curr + off + 1 >= end_old) 364 off += delta; 365 else if (curr >= end_new && curr + off + 1 < end_new) 366 off -= delta; 367 if (off < off_min || off > off_max) 368 return -ERANGE; 369 if (!probe_pass) 370 insn->off = off; 371 return 0; 372 } 373 374 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 375 s32 end_new, const bool probe_pass) 376 { 377 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 378 struct bpf_insn *insn = prog->insnsi; 379 int ret = 0; 380 381 for (i = 0; i < insn_cnt; i++, insn++) { 382 u8 code; 383 384 /* In the probing pass we still operate on the original, 385 * unpatched image in order to check overflows before we 386 * do any other adjustments. Therefore skip the patchlet. 387 */ 388 if (probe_pass && i == pos) { 389 i = end_new; 390 insn = prog->insnsi + end_old; 391 } 392 code = insn->code; 393 if ((BPF_CLASS(code) != BPF_JMP && 394 BPF_CLASS(code) != BPF_JMP32) || 395 BPF_OP(code) == BPF_EXIT) 396 continue; 397 /* Adjust offset of jmps if we cross patch boundaries. */ 398 if (BPF_OP(code) == BPF_CALL) { 399 if (insn->src_reg != BPF_PSEUDO_CALL) 400 continue; 401 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 402 end_new, i, probe_pass); 403 } else { 404 ret = bpf_adj_delta_to_off(insn, pos, end_old, 405 end_new, i, probe_pass); 406 } 407 if (ret) 408 break; 409 } 410 411 return ret; 412 } 413 414 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 415 { 416 struct bpf_line_info *linfo; 417 u32 i, nr_linfo; 418 419 nr_linfo = prog->aux->nr_linfo; 420 if (!nr_linfo || !delta) 421 return; 422 423 linfo = prog->aux->linfo; 424 425 for (i = 0; i < nr_linfo; i++) 426 if (off < linfo[i].insn_off) 427 break; 428 429 /* Push all off < linfo[i].insn_off by delta */ 430 for (; i < nr_linfo; i++) 431 linfo[i].insn_off += delta; 432 } 433 434 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 435 const struct bpf_insn *patch, u32 len) 436 { 437 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 438 const u32 cnt_max = S16_MAX; 439 struct bpf_prog *prog_adj; 440 int err; 441 442 /* Since our patchlet doesn't expand the image, we're done. */ 443 if (insn_delta == 0) { 444 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 445 return prog; 446 } 447 448 insn_adj_cnt = prog->len + insn_delta; 449 450 /* Reject anything that would potentially let the insn->off 451 * target overflow when we have excessive program expansions. 452 * We need to probe here before we do any reallocation where 453 * we afterwards may not fail anymore. 454 */ 455 if (insn_adj_cnt > cnt_max && 456 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 457 return ERR_PTR(err); 458 459 /* Several new instructions need to be inserted. Make room 460 * for them. Likely, there's no need for a new allocation as 461 * last page could have large enough tailroom. 462 */ 463 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 464 GFP_USER); 465 if (!prog_adj) 466 return ERR_PTR(-ENOMEM); 467 468 prog_adj->len = insn_adj_cnt; 469 470 /* Patching happens in 3 steps: 471 * 472 * 1) Move over tail of insnsi from next instruction onwards, 473 * so we can patch the single target insn with one or more 474 * new ones (patching is always from 1 to n insns, n > 0). 475 * 2) Inject new instructions at the target location. 476 * 3) Adjust branch offsets if necessary. 477 */ 478 insn_rest = insn_adj_cnt - off - len; 479 480 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 481 sizeof(*patch) * insn_rest); 482 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 483 484 /* We are guaranteed to not fail at this point, otherwise 485 * the ship has sailed to reverse to the original state. An 486 * overflow cannot happen at this point. 487 */ 488 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 489 490 bpf_adj_linfo(prog_adj, off, insn_delta); 491 492 return prog_adj; 493 } 494 495 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 496 { 497 /* Branch offsets can't overflow when program is shrinking, no need 498 * to call bpf_adj_branches(..., true) here 499 */ 500 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 501 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 502 prog->len -= cnt; 503 504 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 505 } 506 507 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 508 { 509 int i; 510 511 for (i = 0; i < fp->aux->func_cnt; i++) 512 bpf_prog_kallsyms_del(fp->aux->func[i]); 513 } 514 515 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 516 { 517 bpf_prog_kallsyms_del_subprogs(fp); 518 bpf_prog_kallsyms_del(fp); 519 } 520 521 #ifdef CONFIG_BPF_JIT 522 /* All BPF JIT sysctl knobs here. */ 523 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 524 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 525 int bpf_jit_harden __read_mostly; 526 long bpf_jit_limit __read_mostly; 527 528 static void 529 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 530 { 531 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog); 532 unsigned long addr = (unsigned long)hdr; 533 534 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 535 536 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 537 prog->aux->ksym.end = addr + hdr->pages * PAGE_SIZE; 538 } 539 540 static void 541 bpf_prog_ksym_set_name(struct bpf_prog *prog) 542 { 543 char *sym = prog->aux->ksym.name; 544 const char *end = sym + KSYM_NAME_LEN; 545 const struct btf_type *type; 546 const char *func_name; 547 548 BUILD_BUG_ON(sizeof("bpf_prog_") + 549 sizeof(prog->tag) * 2 + 550 /* name has been null terminated. 551 * We should need +1 for the '_' preceding 552 * the name. However, the null character 553 * is double counted between the name and the 554 * sizeof("bpf_prog_") above, so we omit 555 * the +1 here. 556 */ 557 sizeof(prog->aux->name) > KSYM_NAME_LEN); 558 559 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 560 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 561 562 /* prog->aux->name will be ignored if full btf name is available */ 563 if (prog->aux->func_info_cnt) { 564 type = btf_type_by_id(prog->aux->btf, 565 prog->aux->func_info[prog->aux->func_idx].type_id); 566 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 567 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 568 return; 569 } 570 571 if (prog->aux->name[0]) 572 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 573 else 574 *sym = 0; 575 } 576 577 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 578 { 579 return container_of(n, struct bpf_ksym, tnode)->start; 580 } 581 582 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 583 struct latch_tree_node *b) 584 { 585 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 586 } 587 588 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 589 { 590 unsigned long val = (unsigned long)key; 591 const struct bpf_ksym *ksym; 592 593 ksym = container_of(n, struct bpf_ksym, tnode); 594 595 if (val < ksym->start) 596 return -1; 597 if (val >= ksym->end) 598 return 1; 599 600 return 0; 601 } 602 603 static const struct latch_tree_ops bpf_tree_ops = { 604 .less = bpf_tree_less, 605 .comp = bpf_tree_comp, 606 }; 607 608 static DEFINE_SPINLOCK(bpf_lock); 609 static LIST_HEAD(bpf_kallsyms); 610 static struct latch_tree_root bpf_tree __cacheline_aligned; 611 612 void bpf_ksym_add(struct bpf_ksym *ksym) 613 { 614 spin_lock_bh(&bpf_lock); 615 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 616 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 617 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 618 spin_unlock_bh(&bpf_lock); 619 } 620 621 static void __bpf_ksym_del(struct bpf_ksym *ksym) 622 { 623 if (list_empty(&ksym->lnode)) 624 return; 625 626 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 627 list_del_rcu(&ksym->lnode); 628 } 629 630 void bpf_ksym_del(struct bpf_ksym *ksym) 631 { 632 spin_lock_bh(&bpf_lock); 633 __bpf_ksym_del(ksym); 634 spin_unlock_bh(&bpf_lock); 635 } 636 637 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 638 { 639 return fp->jited && !bpf_prog_was_classic(fp); 640 } 641 642 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) 643 { 644 return list_empty(&fp->aux->ksym.lnode) || 645 fp->aux->ksym.lnode.prev == LIST_POISON2; 646 } 647 648 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 649 { 650 if (!bpf_prog_kallsyms_candidate(fp) || 651 !bpf_capable()) 652 return; 653 654 bpf_prog_ksym_set_addr(fp); 655 bpf_prog_ksym_set_name(fp); 656 fp->aux->ksym.prog = true; 657 658 bpf_ksym_add(&fp->aux->ksym); 659 } 660 661 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 662 { 663 if (!bpf_prog_kallsyms_candidate(fp)) 664 return; 665 666 bpf_ksym_del(&fp->aux->ksym); 667 } 668 669 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 670 { 671 struct latch_tree_node *n; 672 673 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 674 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 675 } 676 677 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 678 unsigned long *off, char *sym) 679 { 680 struct bpf_ksym *ksym; 681 char *ret = NULL; 682 683 rcu_read_lock(); 684 ksym = bpf_ksym_find(addr); 685 if (ksym) { 686 unsigned long symbol_start = ksym->start; 687 unsigned long symbol_end = ksym->end; 688 689 strncpy(sym, ksym->name, KSYM_NAME_LEN); 690 691 ret = sym; 692 if (size) 693 *size = symbol_end - symbol_start; 694 if (off) 695 *off = addr - symbol_start; 696 } 697 rcu_read_unlock(); 698 699 return ret; 700 } 701 702 bool is_bpf_text_address(unsigned long addr) 703 { 704 bool ret; 705 706 rcu_read_lock(); 707 ret = bpf_ksym_find(addr) != NULL; 708 rcu_read_unlock(); 709 710 return ret; 711 } 712 713 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 714 { 715 struct bpf_ksym *ksym = bpf_ksym_find(addr); 716 717 return ksym && ksym->prog ? 718 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 719 NULL; 720 } 721 722 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 723 { 724 const struct exception_table_entry *e = NULL; 725 struct bpf_prog *prog; 726 727 rcu_read_lock(); 728 prog = bpf_prog_ksym_find(addr); 729 if (!prog) 730 goto out; 731 if (!prog->aux->num_exentries) 732 goto out; 733 734 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 735 out: 736 rcu_read_unlock(); 737 return e; 738 } 739 740 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 741 char *sym) 742 { 743 struct bpf_ksym *ksym; 744 unsigned int it = 0; 745 int ret = -ERANGE; 746 747 if (!bpf_jit_kallsyms_enabled()) 748 return ret; 749 750 rcu_read_lock(); 751 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 752 if (it++ != symnum) 753 continue; 754 755 strncpy(sym, ksym->name, KSYM_NAME_LEN); 756 757 *value = ksym->start; 758 *type = BPF_SYM_ELF_TYPE; 759 760 ret = 0; 761 break; 762 } 763 rcu_read_unlock(); 764 765 return ret; 766 } 767 768 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 769 struct bpf_jit_poke_descriptor *poke) 770 { 771 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 772 static const u32 poke_tab_max = 1024; 773 u32 slot = prog->aux->size_poke_tab; 774 u32 size = slot + 1; 775 776 if (size > poke_tab_max) 777 return -ENOSPC; 778 if (poke->tailcall_target || poke->tailcall_target_stable || 779 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 780 return -EINVAL; 781 782 switch (poke->reason) { 783 case BPF_POKE_REASON_TAIL_CALL: 784 if (!poke->tail_call.map) 785 return -EINVAL; 786 break; 787 default: 788 return -EINVAL; 789 } 790 791 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 792 if (!tab) 793 return -ENOMEM; 794 795 memcpy(&tab[slot], poke, sizeof(*poke)); 796 prog->aux->size_poke_tab = size; 797 prog->aux->poke_tab = tab; 798 799 return slot; 800 } 801 802 static atomic_long_t bpf_jit_current; 803 804 /* Can be overridden by an arch's JIT compiler if it has a custom, 805 * dedicated BPF backend memory area, or if neither of the two 806 * below apply. 807 */ 808 u64 __weak bpf_jit_alloc_exec_limit(void) 809 { 810 #if defined(MODULES_VADDR) 811 return MODULES_END - MODULES_VADDR; 812 #else 813 return VMALLOC_END - VMALLOC_START; 814 #endif 815 } 816 817 static int __init bpf_jit_charge_init(void) 818 { 819 /* Only used as heuristic here to derive limit. */ 820 bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2, 821 PAGE_SIZE), LONG_MAX); 822 return 0; 823 } 824 pure_initcall(bpf_jit_charge_init); 825 826 int bpf_jit_charge_modmem(u32 pages) 827 { 828 if (atomic_long_add_return(pages, &bpf_jit_current) > 829 (bpf_jit_limit >> PAGE_SHIFT)) { 830 if (!capable(CAP_SYS_ADMIN)) { 831 atomic_long_sub(pages, &bpf_jit_current); 832 return -EPERM; 833 } 834 } 835 836 return 0; 837 } 838 839 void bpf_jit_uncharge_modmem(u32 pages) 840 { 841 atomic_long_sub(pages, &bpf_jit_current); 842 } 843 844 void *__weak bpf_jit_alloc_exec(unsigned long size) 845 { 846 return module_alloc(size); 847 } 848 849 void __weak bpf_jit_free_exec(void *addr) 850 { 851 module_memfree(addr); 852 } 853 854 struct bpf_binary_header * 855 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 856 unsigned int alignment, 857 bpf_jit_fill_hole_t bpf_fill_ill_insns) 858 { 859 struct bpf_binary_header *hdr; 860 u32 size, hole, start, pages; 861 862 WARN_ON_ONCE(!is_power_of_2(alignment) || 863 alignment > BPF_IMAGE_ALIGNMENT); 864 865 /* Most of BPF filters are really small, but if some of them 866 * fill a page, allow at least 128 extra bytes to insert a 867 * random section of illegal instructions. 868 */ 869 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 870 pages = size / PAGE_SIZE; 871 872 if (bpf_jit_charge_modmem(pages)) 873 return NULL; 874 hdr = bpf_jit_alloc_exec(size); 875 if (!hdr) { 876 bpf_jit_uncharge_modmem(pages); 877 return NULL; 878 } 879 880 /* Fill space with illegal/arch-dep instructions. */ 881 bpf_fill_ill_insns(hdr, size); 882 883 hdr->pages = pages; 884 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 885 PAGE_SIZE - sizeof(*hdr)); 886 start = (get_random_int() % hole) & ~(alignment - 1); 887 888 /* Leave a random number of instructions before BPF code. */ 889 *image_ptr = &hdr->image[start]; 890 891 return hdr; 892 } 893 894 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 895 { 896 u32 pages = hdr->pages; 897 898 bpf_jit_free_exec(hdr); 899 bpf_jit_uncharge_modmem(pages); 900 } 901 902 /* This symbol is only overridden by archs that have different 903 * requirements than the usual eBPF JITs, f.e. when they only 904 * implement cBPF JIT, do not set images read-only, etc. 905 */ 906 void __weak bpf_jit_free(struct bpf_prog *fp) 907 { 908 if (fp->jited) { 909 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 910 911 bpf_jit_binary_free(hdr); 912 913 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 914 } 915 916 bpf_prog_unlock_free(fp); 917 } 918 919 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 920 const struct bpf_insn *insn, bool extra_pass, 921 u64 *func_addr, bool *func_addr_fixed) 922 { 923 s16 off = insn->off; 924 s32 imm = insn->imm; 925 u8 *addr; 926 927 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 928 if (!*func_addr_fixed) { 929 /* Place-holder address till the last pass has collected 930 * all addresses for JITed subprograms in which case we 931 * can pick them up from prog->aux. 932 */ 933 if (!extra_pass) 934 addr = NULL; 935 else if (prog->aux->func && 936 off >= 0 && off < prog->aux->func_cnt) 937 addr = (u8 *)prog->aux->func[off]->bpf_func; 938 else 939 return -EINVAL; 940 } else { 941 /* Address of a BPF helper call. Since part of the core 942 * kernel, it's always at a fixed location. __bpf_call_base 943 * and the helper with imm relative to it are both in core 944 * kernel. 945 */ 946 addr = (u8 *)__bpf_call_base + imm; 947 } 948 949 *func_addr = (unsigned long)addr; 950 return 0; 951 } 952 953 static int bpf_jit_blind_insn(const struct bpf_insn *from, 954 const struct bpf_insn *aux, 955 struct bpf_insn *to_buff, 956 bool emit_zext) 957 { 958 struct bpf_insn *to = to_buff; 959 u32 imm_rnd = get_random_int(); 960 s16 off; 961 962 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 963 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 964 965 /* Constraints on AX register: 966 * 967 * AX register is inaccessible from user space. It is mapped in 968 * all JITs, and used here for constant blinding rewrites. It is 969 * typically "stateless" meaning its contents are only valid within 970 * the executed instruction, but not across several instructions. 971 * There are a few exceptions however which are further detailed 972 * below. 973 * 974 * Constant blinding is only used by JITs, not in the interpreter. 975 * The interpreter uses AX in some occasions as a local temporary 976 * register e.g. in DIV or MOD instructions. 977 * 978 * In restricted circumstances, the verifier can also use the AX 979 * register for rewrites as long as they do not interfere with 980 * the above cases! 981 */ 982 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 983 goto out; 984 985 if (from->imm == 0 && 986 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 987 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 988 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 989 goto out; 990 } 991 992 switch (from->code) { 993 case BPF_ALU | BPF_ADD | BPF_K: 994 case BPF_ALU | BPF_SUB | BPF_K: 995 case BPF_ALU | BPF_AND | BPF_K: 996 case BPF_ALU | BPF_OR | BPF_K: 997 case BPF_ALU | BPF_XOR | BPF_K: 998 case BPF_ALU | BPF_MUL | BPF_K: 999 case BPF_ALU | BPF_MOV | BPF_K: 1000 case BPF_ALU | BPF_DIV | BPF_K: 1001 case BPF_ALU | BPF_MOD | BPF_K: 1002 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1003 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1004 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1005 break; 1006 1007 case BPF_ALU64 | BPF_ADD | BPF_K: 1008 case BPF_ALU64 | BPF_SUB | BPF_K: 1009 case BPF_ALU64 | BPF_AND | BPF_K: 1010 case BPF_ALU64 | BPF_OR | BPF_K: 1011 case BPF_ALU64 | BPF_XOR | BPF_K: 1012 case BPF_ALU64 | BPF_MUL | BPF_K: 1013 case BPF_ALU64 | BPF_MOV | BPF_K: 1014 case BPF_ALU64 | BPF_DIV | BPF_K: 1015 case BPF_ALU64 | BPF_MOD | BPF_K: 1016 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1017 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1018 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1019 break; 1020 1021 case BPF_JMP | BPF_JEQ | BPF_K: 1022 case BPF_JMP | BPF_JNE | BPF_K: 1023 case BPF_JMP | BPF_JGT | BPF_K: 1024 case BPF_JMP | BPF_JLT | BPF_K: 1025 case BPF_JMP | BPF_JGE | BPF_K: 1026 case BPF_JMP | BPF_JLE | BPF_K: 1027 case BPF_JMP | BPF_JSGT | BPF_K: 1028 case BPF_JMP | BPF_JSLT | BPF_K: 1029 case BPF_JMP | BPF_JSGE | BPF_K: 1030 case BPF_JMP | BPF_JSLE | BPF_K: 1031 case BPF_JMP | BPF_JSET | BPF_K: 1032 /* Accommodate for extra offset in case of a backjump. */ 1033 off = from->off; 1034 if (off < 0) 1035 off -= 2; 1036 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1037 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1038 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1039 break; 1040 1041 case BPF_JMP32 | BPF_JEQ | BPF_K: 1042 case BPF_JMP32 | BPF_JNE | BPF_K: 1043 case BPF_JMP32 | BPF_JGT | BPF_K: 1044 case BPF_JMP32 | BPF_JLT | BPF_K: 1045 case BPF_JMP32 | BPF_JGE | BPF_K: 1046 case BPF_JMP32 | BPF_JLE | BPF_K: 1047 case BPF_JMP32 | BPF_JSGT | BPF_K: 1048 case BPF_JMP32 | BPF_JSLT | BPF_K: 1049 case BPF_JMP32 | BPF_JSGE | BPF_K: 1050 case BPF_JMP32 | BPF_JSLE | BPF_K: 1051 case BPF_JMP32 | BPF_JSET | BPF_K: 1052 /* Accommodate for extra offset in case of a backjump. */ 1053 off = from->off; 1054 if (off < 0) 1055 off -= 2; 1056 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1057 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1058 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1059 off); 1060 break; 1061 1062 case BPF_LD | BPF_IMM | BPF_DW: 1063 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1064 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1065 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1066 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1067 break; 1068 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1069 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1070 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1071 if (emit_zext) 1072 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1073 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1074 break; 1075 1076 case BPF_ST | BPF_MEM | BPF_DW: 1077 case BPF_ST | BPF_MEM | BPF_W: 1078 case BPF_ST | BPF_MEM | BPF_H: 1079 case BPF_ST | BPF_MEM | BPF_B: 1080 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1081 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1082 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1083 break; 1084 } 1085 out: 1086 return to - to_buff; 1087 } 1088 1089 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1090 gfp_t gfp_extra_flags) 1091 { 1092 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1093 struct bpf_prog *fp; 1094 1095 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1096 if (fp != NULL) { 1097 /* aux->prog still points to the fp_other one, so 1098 * when promoting the clone to the real program, 1099 * this still needs to be adapted. 1100 */ 1101 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1102 } 1103 1104 return fp; 1105 } 1106 1107 static void bpf_prog_clone_free(struct bpf_prog *fp) 1108 { 1109 /* aux was stolen by the other clone, so we cannot free 1110 * it from this path! It will be freed eventually by the 1111 * other program on release. 1112 * 1113 * At this point, we don't need a deferred release since 1114 * clone is guaranteed to not be locked. 1115 */ 1116 fp->aux = NULL; 1117 fp->stats = NULL; 1118 fp->active = NULL; 1119 __bpf_prog_free(fp); 1120 } 1121 1122 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1123 { 1124 /* We have to repoint aux->prog to self, as we don't 1125 * know whether fp here is the clone or the original. 1126 */ 1127 fp->aux->prog = fp; 1128 bpf_prog_clone_free(fp_other); 1129 } 1130 1131 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1132 { 1133 struct bpf_insn insn_buff[16], aux[2]; 1134 struct bpf_prog *clone, *tmp; 1135 int insn_delta, insn_cnt; 1136 struct bpf_insn *insn; 1137 int i, rewritten; 1138 1139 if (!bpf_jit_blinding_enabled(prog) || prog->blinded) 1140 return prog; 1141 1142 clone = bpf_prog_clone_create(prog, GFP_USER); 1143 if (!clone) 1144 return ERR_PTR(-ENOMEM); 1145 1146 insn_cnt = clone->len; 1147 insn = clone->insnsi; 1148 1149 for (i = 0; i < insn_cnt; i++, insn++) { 1150 /* We temporarily need to hold the original ld64 insn 1151 * so that we can still access the first part in the 1152 * second blinding run. 1153 */ 1154 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1155 insn[1].code == 0) 1156 memcpy(aux, insn, sizeof(aux)); 1157 1158 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1159 clone->aux->verifier_zext); 1160 if (!rewritten) 1161 continue; 1162 1163 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1164 if (IS_ERR(tmp)) { 1165 /* Patching may have repointed aux->prog during 1166 * realloc from the original one, so we need to 1167 * fix it up here on error. 1168 */ 1169 bpf_jit_prog_release_other(prog, clone); 1170 return tmp; 1171 } 1172 1173 clone = tmp; 1174 insn_delta = rewritten - 1; 1175 1176 /* Walk new program and skip insns we just inserted. */ 1177 insn = clone->insnsi + i + insn_delta; 1178 insn_cnt += insn_delta; 1179 i += insn_delta; 1180 } 1181 1182 clone->blinded = 1; 1183 return clone; 1184 } 1185 #endif /* CONFIG_BPF_JIT */ 1186 1187 /* Base function for offset calculation. Needs to go into .text section, 1188 * therefore keeping it non-static as well; will also be used by JITs 1189 * anyway later on, so do not let the compiler omit it. This also needs 1190 * to go into kallsyms for correlation from e.g. bpftool, so naming 1191 * must not change. 1192 */ 1193 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1194 { 1195 return 0; 1196 } 1197 EXPORT_SYMBOL_GPL(__bpf_call_base); 1198 1199 /* All UAPI available opcodes. */ 1200 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1201 /* 32 bit ALU operations. */ \ 1202 /* Register based. */ \ 1203 INSN_3(ALU, ADD, X), \ 1204 INSN_3(ALU, SUB, X), \ 1205 INSN_3(ALU, AND, X), \ 1206 INSN_3(ALU, OR, X), \ 1207 INSN_3(ALU, LSH, X), \ 1208 INSN_3(ALU, RSH, X), \ 1209 INSN_3(ALU, XOR, X), \ 1210 INSN_3(ALU, MUL, X), \ 1211 INSN_3(ALU, MOV, X), \ 1212 INSN_3(ALU, ARSH, X), \ 1213 INSN_3(ALU, DIV, X), \ 1214 INSN_3(ALU, MOD, X), \ 1215 INSN_2(ALU, NEG), \ 1216 INSN_3(ALU, END, TO_BE), \ 1217 INSN_3(ALU, END, TO_LE), \ 1218 /* Immediate based. */ \ 1219 INSN_3(ALU, ADD, K), \ 1220 INSN_3(ALU, SUB, K), \ 1221 INSN_3(ALU, AND, K), \ 1222 INSN_3(ALU, OR, K), \ 1223 INSN_3(ALU, LSH, K), \ 1224 INSN_3(ALU, RSH, K), \ 1225 INSN_3(ALU, XOR, K), \ 1226 INSN_3(ALU, MUL, K), \ 1227 INSN_3(ALU, MOV, K), \ 1228 INSN_3(ALU, ARSH, K), \ 1229 INSN_3(ALU, DIV, K), \ 1230 INSN_3(ALU, MOD, K), \ 1231 /* 64 bit ALU operations. */ \ 1232 /* Register based. */ \ 1233 INSN_3(ALU64, ADD, X), \ 1234 INSN_3(ALU64, SUB, X), \ 1235 INSN_3(ALU64, AND, X), \ 1236 INSN_3(ALU64, OR, X), \ 1237 INSN_3(ALU64, LSH, X), \ 1238 INSN_3(ALU64, RSH, X), \ 1239 INSN_3(ALU64, XOR, X), \ 1240 INSN_3(ALU64, MUL, X), \ 1241 INSN_3(ALU64, MOV, X), \ 1242 INSN_3(ALU64, ARSH, X), \ 1243 INSN_3(ALU64, DIV, X), \ 1244 INSN_3(ALU64, MOD, X), \ 1245 INSN_2(ALU64, NEG), \ 1246 /* Immediate based. */ \ 1247 INSN_3(ALU64, ADD, K), \ 1248 INSN_3(ALU64, SUB, K), \ 1249 INSN_3(ALU64, AND, K), \ 1250 INSN_3(ALU64, OR, K), \ 1251 INSN_3(ALU64, LSH, K), \ 1252 INSN_3(ALU64, RSH, K), \ 1253 INSN_3(ALU64, XOR, K), \ 1254 INSN_3(ALU64, MUL, K), \ 1255 INSN_3(ALU64, MOV, K), \ 1256 INSN_3(ALU64, ARSH, K), \ 1257 INSN_3(ALU64, DIV, K), \ 1258 INSN_3(ALU64, MOD, K), \ 1259 /* Call instruction. */ \ 1260 INSN_2(JMP, CALL), \ 1261 /* Exit instruction. */ \ 1262 INSN_2(JMP, EXIT), \ 1263 /* 32-bit Jump instructions. */ \ 1264 /* Register based. */ \ 1265 INSN_3(JMP32, JEQ, X), \ 1266 INSN_3(JMP32, JNE, X), \ 1267 INSN_3(JMP32, JGT, X), \ 1268 INSN_3(JMP32, JLT, X), \ 1269 INSN_3(JMP32, JGE, X), \ 1270 INSN_3(JMP32, JLE, X), \ 1271 INSN_3(JMP32, JSGT, X), \ 1272 INSN_3(JMP32, JSLT, X), \ 1273 INSN_3(JMP32, JSGE, X), \ 1274 INSN_3(JMP32, JSLE, X), \ 1275 INSN_3(JMP32, JSET, X), \ 1276 /* Immediate based. */ \ 1277 INSN_3(JMP32, JEQ, K), \ 1278 INSN_3(JMP32, JNE, K), \ 1279 INSN_3(JMP32, JGT, K), \ 1280 INSN_3(JMP32, JLT, K), \ 1281 INSN_3(JMP32, JGE, K), \ 1282 INSN_3(JMP32, JLE, K), \ 1283 INSN_3(JMP32, JSGT, K), \ 1284 INSN_3(JMP32, JSLT, K), \ 1285 INSN_3(JMP32, JSGE, K), \ 1286 INSN_3(JMP32, JSLE, K), \ 1287 INSN_3(JMP32, JSET, K), \ 1288 /* Jump instructions. */ \ 1289 /* Register based. */ \ 1290 INSN_3(JMP, JEQ, X), \ 1291 INSN_3(JMP, JNE, X), \ 1292 INSN_3(JMP, JGT, X), \ 1293 INSN_3(JMP, JLT, X), \ 1294 INSN_3(JMP, JGE, X), \ 1295 INSN_3(JMP, JLE, X), \ 1296 INSN_3(JMP, JSGT, X), \ 1297 INSN_3(JMP, JSLT, X), \ 1298 INSN_3(JMP, JSGE, X), \ 1299 INSN_3(JMP, JSLE, X), \ 1300 INSN_3(JMP, JSET, X), \ 1301 /* Immediate based. */ \ 1302 INSN_3(JMP, JEQ, K), \ 1303 INSN_3(JMP, JNE, K), \ 1304 INSN_3(JMP, JGT, K), \ 1305 INSN_3(JMP, JLT, K), \ 1306 INSN_3(JMP, JGE, K), \ 1307 INSN_3(JMP, JLE, K), \ 1308 INSN_3(JMP, JSGT, K), \ 1309 INSN_3(JMP, JSLT, K), \ 1310 INSN_3(JMP, JSGE, K), \ 1311 INSN_3(JMP, JSLE, K), \ 1312 INSN_3(JMP, JSET, K), \ 1313 INSN_2(JMP, JA), \ 1314 /* Store instructions. */ \ 1315 /* Register based. */ \ 1316 INSN_3(STX, MEM, B), \ 1317 INSN_3(STX, MEM, H), \ 1318 INSN_3(STX, MEM, W), \ 1319 INSN_3(STX, MEM, DW), \ 1320 INSN_3(STX, ATOMIC, W), \ 1321 INSN_3(STX, ATOMIC, DW), \ 1322 /* Immediate based. */ \ 1323 INSN_3(ST, MEM, B), \ 1324 INSN_3(ST, MEM, H), \ 1325 INSN_3(ST, MEM, W), \ 1326 INSN_3(ST, MEM, DW), \ 1327 /* Load instructions. */ \ 1328 /* Register based. */ \ 1329 INSN_3(LDX, MEM, B), \ 1330 INSN_3(LDX, MEM, H), \ 1331 INSN_3(LDX, MEM, W), \ 1332 INSN_3(LDX, MEM, DW), \ 1333 /* Immediate based. */ \ 1334 INSN_3(LD, IMM, DW) 1335 1336 bool bpf_opcode_in_insntable(u8 code) 1337 { 1338 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1339 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1340 static const bool public_insntable[256] = { 1341 [0 ... 255] = false, 1342 /* Now overwrite non-defaults ... */ 1343 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1344 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1345 [BPF_LD | BPF_ABS | BPF_B] = true, 1346 [BPF_LD | BPF_ABS | BPF_H] = true, 1347 [BPF_LD | BPF_ABS | BPF_W] = true, 1348 [BPF_LD | BPF_IND | BPF_B] = true, 1349 [BPF_LD | BPF_IND | BPF_H] = true, 1350 [BPF_LD | BPF_IND | BPF_W] = true, 1351 }; 1352 #undef BPF_INSN_3_TBL 1353 #undef BPF_INSN_2_TBL 1354 return public_insntable[code]; 1355 } 1356 1357 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1358 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1359 { 1360 memset(dst, 0, size); 1361 return -EFAULT; 1362 } 1363 1364 /** 1365 * ___bpf_prog_run - run eBPF program on a given context 1366 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1367 * @insn: is the array of eBPF instructions 1368 * 1369 * Decode and execute eBPF instructions. 1370 * 1371 * Return: whatever value is in %BPF_R0 at program exit 1372 */ 1373 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1374 { 1375 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1376 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1377 static const void * const jumptable[256] __annotate_jump_table = { 1378 [0 ... 255] = &&default_label, 1379 /* Now overwrite non-defaults ... */ 1380 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1381 /* Non-UAPI available opcodes. */ 1382 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1383 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1384 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1385 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1386 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1387 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1388 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1389 }; 1390 #undef BPF_INSN_3_LBL 1391 #undef BPF_INSN_2_LBL 1392 u32 tail_call_cnt = 0; 1393 1394 #define CONT ({ insn++; goto select_insn; }) 1395 #define CONT_JMP ({ insn++; goto select_insn; }) 1396 1397 select_insn: 1398 goto *jumptable[insn->code]; 1399 1400 /* Explicitly mask the register-based shift amounts with 63 or 31 1401 * to avoid undefined behavior. Normally this won't affect the 1402 * generated code, for example, in case of native 64 bit archs such 1403 * as x86-64 or arm64, the compiler is optimizing the AND away for 1404 * the interpreter. In case of JITs, each of the JIT backends compiles 1405 * the BPF shift operations to machine instructions which produce 1406 * implementation-defined results in such a case; the resulting 1407 * contents of the register may be arbitrary, but program behaviour 1408 * as a whole remains defined. In other words, in case of JIT backends, 1409 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1410 */ 1411 /* ALU (shifts) */ 1412 #define SHT(OPCODE, OP) \ 1413 ALU64_##OPCODE##_X: \ 1414 DST = DST OP (SRC & 63); \ 1415 CONT; \ 1416 ALU_##OPCODE##_X: \ 1417 DST = (u32) DST OP ((u32) SRC & 31); \ 1418 CONT; \ 1419 ALU64_##OPCODE##_K: \ 1420 DST = DST OP IMM; \ 1421 CONT; \ 1422 ALU_##OPCODE##_K: \ 1423 DST = (u32) DST OP (u32) IMM; \ 1424 CONT; 1425 /* ALU (rest) */ 1426 #define ALU(OPCODE, OP) \ 1427 ALU64_##OPCODE##_X: \ 1428 DST = DST OP SRC; \ 1429 CONT; \ 1430 ALU_##OPCODE##_X: \ 1431 DST = (u32) DST OP (u32) SRC; \ 1432 CONT; \ 1433 ALU64_##OPCODE##_K: \ 1434 DST = DST OP IMM; \ 1435 CONT; \ 1436 ALU_##OPCODE##_K: \ 1437 DST = (u32) DST OP (u32) IMM; \ 1438 CONT; 1439 ALU(ADD, +) 1440 ALU(SUB, -) 1441 ALU(AND, &) 1442 ALU(OR, |) 1443 ALU(XOR, ^) 1444 ALU(MUL, *) 1445 SHT(LSH, <<) 1446 SHT(RSH, >>) 1447 #undef SHT 1448 #undef ALU 1449 ALU_NEG: 1450 DST = (u32) -DST; 1451 CONT; 1452 ALU64_NEG: 1453 DST = -DST; 1454 CONT; 1455 ALU_MOV_X: 1456 DST = (u32) SRC; 1457 CONT; 1458 ALU_MOV_K: 1459 DST = (u32) IMM; 1460 CONT; 1461 ALU64_MOV_X: 1462 DST = SRC; 1463 CONT; 1464 ALU64_MOV_K: 1465 DST = IMM; 1466 CONT; 1467 LD_IMM_DW: 1468 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1469 insn++; 1470 CONT; 1471 ALU_ARSH_X: 1472 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1473 CONT; 1474 ALU_ARSH_K: 1475 DST = (u64) (u32) (((s32) DST) >> IMM); 1476 CONT; 1477 ALU64_ARSH_X: 1478 (*(s64 *) &DST) >>= (SRC & 63); 1479 CONT; 1480 ALU64_ARSH_K: 1481 (*(s64 *) &DST) >>= IMM; 1482 CONT; 1483 ALU64_MOD_X: 1484 div64_u64_rem(DST, SRC, &AX); 1485 DST = AX; 1486 CONT; 1487 ALU_MOD_X: 1488 AX = (u32) DST; 1489 DST = do_div(AX, (u32) SRC); 1490 CONT; 1491 ALU64_MOD_K: 1492 div64_u64_rem(DST, IMM, &AX); 1493 DST = AX; 1494 CONT; 1495 ALU_MOD_K: 1496 AX = (u32) DST; 1497 DST = do_div(AX, (u32) IMM); 1498 CONT; 1499 ALU64_DIV_X: 1500 DST = div64_u64(DST, SRC); 1501 CONT; 1502 ALU_DIV_X: 1503 AX = (u32) DST; 1504 do_div(AX, (u32) SRC); 1505 DST = (u32) AX; 1506 CONT; 1507 ALU64_DIV_K: 1508 DST = div64_u64(DST, IMM); 1509 CONT; 1510 ALU_DIV_K: 1511 AX = (u32) DST; 1512 do_div(AX, (u32) IMM); 1513 DST = (u32) AX; 1514 CONT; 1515 ALU_END_TO_BE: 1516 switch (IMM) { 1517 case 16: 1518 DST = (__force u16) cpu_to_be16(DST); 1519 break; 1520 case 32: 1521 DST = (__force u32) cpu_to_be32(DST); 1522 break; 1523 case 64: 1524 DST = (__force u64) cpu_to_be64(DST); 1525 break; 1526 } 1527 CONT; 1528 ALU_END_TO_LE: 1529 switch (IMM) { 1530 case 16: 1531 DST = (__force u16) cpu_to_le16(DST); 1532 break; 1533 case 32: 1534 DST = (__force u32) cpu_to_le32(DST); 1535 break; 1536 case 64: 1537 DST = (__force u64) cpu_to_le64(DST); 1538 break; 1539 } 1540 CONT; 1541 1542 /* CALL */ 1543 JMP_CALL: 1544 /* Function call scratches BPF_R1-BPF_R5 registers, 1545 * preserves BPF_R6-BPF_R9, and stores return value 1546 * into BPF_R0. 1547 */ 1548 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1549 BPF_R4, BPF_R5); 1550 CONT; 1551 1552 JMP_CALL_ARGS: 1553 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1554 BPF_R3, BPF_R4, 1555 BPF_R5, 1556 insn + insn->off + 1); 1557 CONT; 1558 1559 JMP_TAIL_CALL: { 1560 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1561 struct bpf_array *array = container_of(map, struct bpf_array, map); 1562 struct bpf_prog *prog; 1563 u32 index = BPF_R3; 1564 1565 if (unlikely(index >= array->map.max_entries)) 1566 goto out; 1567 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 1568 goto out; 1569 1570 tail_call_cnt++; 1571 1572 prog = READ_ONCE(array->ptrs[index]); 1573 if (!prog) 1574 goto out; 1575 1576 /* ARG1 at this point is guaranteed to point to CTX from 1577 * the verifier side due to the fact that the tail call is 1578 * handled like a helper, that is, bpf_tail_call_proto, 1579 * where arg1_type is ARG_PTR_TO_CTX. 1580 */ 1581 insn = prog->insnsi; 1582 goto select_insn; 1583 out: 1584 CONT; 1585 } 1586 JMP_JA: 1587 insn += insn->off; 1588 CONT; 1589 JMP_EXIT: 1590 return BPF_R0; 1591 /* JMP */ 1592 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1593 JMP_##OPCODE##_X: \ 1594 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1595 insn += insn->off; \ 1596 CONT_JMP; \ 1597 } \ 1598 CONT; \ 1599 JMP32_##OPCODE##_X: \ 1600 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1601 insn += insn->off; \ 1602 CONT_JMP; \ 1603 } \ 1604 CONT; \ 1605 JMP_##OPCODE##_K: \ 1606 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1607 insn += insn->off; \ 1608 CONT_JMP; \ 1609 } \ 1610 CONT; \ 1611 JMP32_##OPCODE##_K: \ 1612 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1613 insn += insn->off; \ 1614 CONT_JMP; \ 1615 } \ 1616 CONT; 1617 COND_JMP(u, JEQ, ==) 1618 COND_JMP(u, JNE, !=) 1619 COND_JMP(u, JGT, >) 1620 COND_JMP(u, JLT, <) 1621 COND_JMP(u, JGE, >=) 1622 COND_JMP(u, JLE, <=) 1623 COND_JMP(u, JSET, &) 1624 COND_JMP(s, JSGT, >) 1625 COND_JMP(s, JSLT, <) 1626 COND_JMP(s, JSGE, >=) 1627 COND_JMP(s, JSLE, <=) 1628 #undef COND_JMP 1629 /* ST, STX and LDX*/ 1630 ST_NOSPEC: 1631 /* Speculation barrier for mitigating Speculative Store Bypass. 1632 * In case of arm64, we rely on the firmware mitigation as 1633 * controlled via the ssbd kernel parameter. Whenever the 1634 * mitigation is enabled, it works for all of the kernel code 1635 * with no need to provide any additional instructions here. 1636 * In case of x86, we use 'lfence' insn for mitigation. We 1637 * reuse preexisting logic from Spectre v1 mitigation that 1638 * happens to produce the required code on x86 for v4 as well. 1639 */ 1640 #ifdef CONFIG_X86 1641 barrier_nospec(); 1642 #endif 1643 CONT; 1644 #define LDST(SIZEOP, SIZE) \ 1645 STX_MEM_##SIZEOP: \ 1646 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1647 CONT; \ 1648 ST_MEM_##SIZEOP: \ 1649 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1650 CONT; \ 1651 LDX_MEM_##SIZEOP: \ 1652 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1653 CONT; 1654 1655 LDST(B, u8) 1656 LDST(H, u16) 1657 LDST(W, u32) 1658 LDST(DW, u64) 1659 #undef LDST 1660 #define LDX_PROBE(SIZEOP, SIZE) \ 1661 LDX_PROBE_MEM_##SIZEOP: \ 1662 bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) (SRC + insn->off)); \ 1663 CONT; 1664 LDX_PROBE(B, 1) 1665 LDX_PROBE(H, 2) 1666 LDX_PROBE(W, 4) 1667 LDX_PROBE(DW, 8) 1668 #undef LDX_PROBE 1669 1670 #define ATOMIC_ALU_OP(BOP, KOP) \ 1671 case BOP: \ 1672 if (BPF_SIZE(insn->code) == BPF_W) \ 1673 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 1674 (DST + insn->off)); \ 1675 else \ 1676 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 1677 (DST + insn->off)); \ 1678 break; \ 1679 case BOP | BPF_FETCH: \ 1680 if (BPF_SIZE(insn->code) == BPF_W) \ 1681 SRC = (u32) atomic_fetch_##KOP( \ 1682 (u32) SRC, \ 1683 (atomic_t *)(unsigned long) (DST + insn->off)); \ 1684 else \ 1685 SRC = (u64) atomic64_fetch_##KOP( \ 1686 (u64) SRC, \ 1687 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 1688 break; 1689 1690 STX_ATOMIC_DW: 1691 STX_ATOMIC_W: 1692 switch (IMM) { 1693 ATOMIC_ALU_OP(BPF_ADD, add) 1694 ATOMIC_ALU_OP(BPF_AND, and) 1695 ATOMIC_ALU_OP(BPF_OR, or) 1696 ATOMIC_ALU_OP(BPF_XOR, xor) 1697 #undef ATOMIC_ALU_OP 1698 1699 case BPF_XCHG: 1700 if (BPF_SIZE(insn->code) == BPF_W) 1701 SRC = (u32) atomic_xchg( 1702 (atomic_t *)(unsigned long) (DST + insn->off), 1703 (u32) SRC); 1704 else 1705 SRC = (u64) atomic64_xchg( 1706 (atomic64_t *)(unsigned long) (DST + insn->off), 1707 (u64) SRC); 1708 break; 1709 case BPF_CMPXCHG: 1710 if (BPF_SIZE(insn->code) == BPF_W) 1711 BPF_R0 = (u32) atomic_cmpxchg( 1712 (atomic_t *)(unsigned long) (DST + insn->off), 1713 (u32) BPF_R0, (u32) SRC); 1714 else 1715 BPF_R0 = (u64) atomic64_cmpxchg( 1716 (atomic64_t *)(unsigned long) (DST + insn->off), 1717 (u64) BPF_R0, (u64) SRC); 1718 break; 1719 1720 default: 1721 goto default_label; 1722 } 1723 CONT; 1724 1725 default_label: 1726 /* If we ever reach this, we have a bug somewhere. Die hard here 1727 * instead of just returning 0; we could be somewhere in a subprog, 1728 * so execution could continue otherwise which we do /not/ want. 1729 * 1730 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 1731 */ 1732 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 1733 insn->code, insn->imm); 1734 BUG_ON(1); 1735 return 0; 1736 } 1737 1738 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 1739 #define DEFINE_BPF_PROG_RUN(stack_size) \ 1740 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 1741 { \ 1742 u64 stack[stack_size / sizeof(u64)]; \ 1743 u64 regs[MAX_BPF_EXT_REG]; \ 1744 \ 1745 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1746 ARG1 = (u64) (unsigned long) ctx; \ 1747 return ___bpf_prog_run(regs, insn); \ 1748 } 1749 1750 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 1751 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 1752 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 1753 const struct bpf_insn *insn) \ 1754 { \ 1755 u64 stack[stack_size / sizeof(u64)]; \ 1756 u64 regs[MAX_BPF_EXT_REG]; \ 1757 \ 1758 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1759 BPF_R1 = r1; \ 1760 BPF_R2 = r2; \ 1761 BPF_R3 = r3; \ 1762 BPF_R4 = r4; \ 1763 BPF_R5 = r5; \ 1764 return ___bpf_prog_run(regs, insn); \ 1765 } 1766 1767 #define EVAL1(FN, X) FN(X) 1768 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 1769 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 1770 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 1771 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 1772 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 1773 1774 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 1775 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 1776 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 1777 1778 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 1779 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 1780 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 1781 1782 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 1783 1784 static unsigned int (*interpreters[])(const void *ctx, 1785 const struct bpf_insn *insn) = { 1786 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1787 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1788 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1789 }; 1790 #undef PROG_NAME_LIST 1791 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 1792 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 1793 const struct bpf_insn *insn) = { 1794 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1795 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1796 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1797 }; 1798 #undef PROG_NAME_LIST 1799 1800 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 1801 { 1802 stack_depth = max_t(u32, stack_depth, 1); 1803 insn->off = (s16) insn->imm; 1804 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 1805 __bpf_call_base_args; 1806 insn->code = BPF_JMP | BPF_CALL_ARGS; 1807 } 1808 1809 #else 1810 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 1811 const struct bpf_insn *insn) 1812 { 1813 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 1814 * is not working properly, so warn about it! 1815 */ 1816 WARN_ON_ONCE(1); 1817 return 0; 1818 } 1819 #endif 1820 1821 bool bpf_prog_array_compatible(struct bpf_array *array, 1822 const struct bpf_prog *fp) 1823 { 1824 if (fp->kprobe_override) 1825 return false; 1826 1827 if (!array->aux->type) { 1828 /* There's no owner yet where we could check for 1829 * compatibility. 1830 */ 1831 array->aux->type = fp->type; 1832 array->aux->jited = fp->jited; 1833 return true; 1834 } 1835 1836 return array->aux->type == fp->type && 1837 array->aux->jited == fp->jited; 1838 } 1839 1840 static int bpf_check_tail_call(const struct bpf_prog *fp) 1841 { 1842 struct bpf_prog_aux *aux = fp->aux; 1843 int i, ret = 0; 1844 1845 mutex_lock(&aux->used_maps_mutex); 1846 for (i = 0; i < aux->used_map_cnt; i++) { 1847 struct bpf_map *map = aux->used_maps[i]; 1848 struct bpf_array *array; 1849 1850 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 1851 continue; 1852 1853 array = container_of(map, struct bpf_array, map); 1854 if (!bpf_prog_array_compatible(array, fp)) { 1855 ret = -EINVAL; 1856 goto out; 1857 } 1858 } 1859 1860 out: 1861 mutex_unlock(&aux->used_maps_mutex); 1862 return ret; 1863 } 1864 1865 static void bpf_prog_select_func(struct bpf_prog *fp) 1866 { 1867 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1868 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 1869 1870 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 1871 #else 1872 fp->bpf_func = __bpf_prog_ret0_warn; 1873 #endif 1874 } 1875 1876 /** 1877 * bpf_prog_select_runtime - select exec runtime for BPF program 1878 * @fp: bpf_prog populated with internal BPF program 1879 * @err: pointer to error variable 1880 * 1881 * Try to JIT eBPF program, if JIT is not available, use interpreter. 1882 * The BPF program will be executed via bpf_prog_run() function. 1883 * 1884 * Return: the &fp argument along with &err set to 0 for success or 1885 * a negative errno code on failure 1886 */ 1887 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 1888 { 1889 /* In case of BPF to BPF calls, verifier did all the prep 1890 * work with regards to JITing, etc. 1891 */ 1892 bool jit_needed = false; 1893 1894 if (fp->bpf_func) 1895 goto finalize; 1896 1897 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 1898 bpf_prog_has_kfunc_call(fp)) 1899 jit_needed = true; 1900 1901 bpf_prog_select_func(fp); 1902 1903 /* eBPF JITs can rewrite the program in case constant 1904 * blinding is active. However, in case of error during 1905 * blinding, bpf_int_jit_compile() must always return a 1906 * valid program, which in this case would simply not 1907 * be JITed, but falls back to the interpreter. 1908 */ 1909 if (!bpf_prog_is_dev_bound(fp->aux)) { 1910 *err = bpf_prog_alloc_jited_linfo(fp); 1911 if (*err) 1912 return fp; 1913 1914 fp = bpf_int_jit_compile(fp); 1915 bpf_prog_jit_attempt_done(fp); 1916 if (!fp->jited && jit_needed) { 1917 *err = -ENOTSUPP; 1918 return fp; 1919 } 1920 } else { 1921 *err = bpf_prog_offload_compile(fp); 1922 if (*err) 1923 return fp; 1924 } 1925 1926 finalize: 1927 bpf_prog_lock_ro(fp); 1928 1929 /* The tail call compatibility check can only be done at 1930 * this late stage as we need to determine, if we deal 1931 * with JITed or non JITed program concatenations and not 1932 * all eBPF JITs might immediately support all features. 1933 */ 1934 *err = bpf_check_tail_call(fp); 1935 1936 return fp; 1937 } 1938 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 1939 1940 static unsigned int __bpf_prog_ret1(const void *ctx, 1941 const struct bpf_insn *insn) 1942 { 1943 return 1; 1944 } 1945 1946 static struct bpf_prog_dummy { 1947 struct bpf_prog prog; 1948 } dummy_bpf_prog = { 1949 .prog = { 1950 .bpf_func = __bpf_prog_ret1, 1951 }, 1952 }; 1953 1954 /* to avoid allocating empty bpf_prog_array for cgroups that 1955 * don't have bpf program attached use one global 'empty_prog_array' 1956 * It will not be modified the caller of bpf_prog_array_alloc() 1957 * (since caller requested prog_cnt == 0) 1958 * that pointer should be 'freed' by bpf_prog_array_free() 1959 */ 1960 static struct { 1961 struct bpf_prog_array hdr; 1962 struct bpf_prog *null_prog; 1963 } empty_prog_array = { 1964 .null_prog = NULL, 1965 }; 1966 1967 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 1968 { 1969 if (prog_cnt) 1970 return kzalloc(sizeof(struct bpf_prog_array) + 1971 sizeof(struct bpf_prog_array_item) * 1972 (prog_cnt + 1), 1973 flags); 1974 1975 return &empty_prog_array.hdr; 1976 } 1977 1978 void bpf_prog_array_free(struct bpf_prog_array *progs) 1979 { 1980 if (!progs || progs == &empty_prog_array.hdr) 1981 return; 1982 kfree_rcu(progs, rcu); 1983 } 1984 1985 int bpf_prog_array_length(struct bpf_prog_array *array) 1986 { 1987 struct bpf_prog_array_item *item; 1988 u32 cnt = 0; 1989 1990 for (item = array->items; item->prog; item++) 1991 if (item->prog != &dummy_bpf_prog.prog) 1992 cnt++; 1993 return cnt; 1994 } 1995 1996 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 1997 { 1998 struct bpf_prog_array_item *item; 1999 2000 for (item = array->items; item->prog; item++) 2001 if (item->prog != &dummy_bpf_prog.prog) 2002 return false; 2003 return true; 2004 } 2005 2006 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2007 u32 *prog_ids, 2008 u32 request_cnt) 2009 { 2010 struct bpf_prog_array_item *item; 2011 int i = 0; 2012 2013 for (item = array->items; item->prog; item++) { 2014 if (item->prog == &dummy_bpf_prog.prog) 2015 continue; 2016 prog_ids[i] = item->prog->aux->id; 2017 if (++i == request_cnt) { 2018 item++; 2019 break; 2020 } 2021 } 2022 2023 return !!(item->prog); 2024 } 2025 2026 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2027 __u32 __user *prog_ids, u32 cnt) 2028 { 2029 unsigned long err = 0; 2030 bool nospc; 2031 u32 *ids; 2032 2033 /* users of this function are doing: 2034 * cnt = bpf_prog_array_length(); 2035 * if (cnt > 0) 2036 * bpf_prog_array_copy_to_user(..., cnt); 2037 * so below kcalloc doesn't need extra cnt > 0 check. 2038 */ 2039 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2040 if (!ids) 2041 return -ENOMEM; 2042 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2043 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2044 kfree(ids); 2045 if (err) 2046 return -EFAULT; 2047 if (nospc) 2048 return -ENOSPC; 2049 return 0; 2050 } 2051 2052 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2053 struct bpf_prog *old_prog) 2054 { 2055 struct bpf_prog_array_item *item; 2056 2057 for (item = array->items; item->prog; item++) 2058 if (item->prog == old_prog) { 2059 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2060 break; 2061 } 2062 } 2063 2064 /** 2065 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2066 * index into the program array with 2067 * a dummy no-op program. 2068 * @array: a bpf_prog_array 2069 * @index: the index of the program to replace 2070 * 2071 * Skips over dummy programs, by not counting them, when calculating 2072 * the position of the program to replace. 2073 * 2074 * Return: 2075 * * 0 - Success 2076 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2077 * * -ENOENT - Index out of range 2078 */ 2079 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2080 { 2081 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2082 } 2083 2084 /** 2085 * bpf_prog_array_update_at() - Updates the program at the given index 2086 * into the program array. 2087 * @array: a bpf_prog_array 2088 * @index: the index of the program to update 2089 * @prog: the program to insert into the array 2090 * 2091 * Skips over dummy programs, by not counting them, when calculating 2092 * the position of the program to update. 2093 * 2094 * Return: 2095 * * 0 - Success 2096 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2097 * * -ENOENT - Index out of range 2098 */ 2099 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2100 struct bpf_prog *prog) 2101 { 2102 struct bpf_prog_array_item *item; 2103 2104 if (unlikely(index < 0)) 2105 return -EINVAL; 2106 2107 for (item = array->items; item->prog; item++) { 2108 if (item->prog == &dummy_bpf_prog.prog) 2109 continue; 2110 if (!index) { 2111 WRITE_ONCE(item->prog, prog); 2112 return 0; 2113 } 2114 index--; 2115 } 2116 return -ENOENT; 2117 } 2118 2119 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2120 struct bpf_prog *exclude_prog, 2121 struct bpf_prog *include_prog, 2122 u64 bpf_cookie, 2123 struct bpf_prog_array **new_array) 2124 { 2125 int new_prog_cnt, carry_prog_cnt = 0; 2126 struct bpf_prog_array_item *existing, *new; 2127 struct bpf_prog_array *array; 2128 bool found_exclude = false; 2129 2130 /* Figure out how many existing progs we need to carry over to 2131 * the new array. 2132 */ 2133 if (old_array) { 2134 existing = old_array->items; 2135 for (; existing->prog; existing++) { 2136 if (existing->prog == exclude_prog) { 2137 found_exclude = true; 2138 continue; 2139 } 2140 if (existing->prog != &dummy_bpf_prog.prog) 2141 carry_prog_cnt++; 2142 if (existing->prog == include_prog) 2143 return -EEXIST; 2144 } 2145 } 2146 2147 if (exclude_prog && !found_exclude) 2148 return -ENOENT; 2149 2150 /* How many progs (not NULL) will be in the new array? */ 2151 new_prog_cnt = carry_prog_cnt; 2152 if (include_prog) 2153 new_prog_cnt += 1; 2154 2155 /* Do we have any prog (not NULL) in the new array? */ 2156 if (!new_prog_cnt) { 2157 *new_array = NULL; 2158 return 0; 2159 } 2160 2161 /* +1 as the end of prog_array is marked with NULL */ 2162 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2163 if (!array) 2164 return -ENOMEM; 2165 new = array->items; 2166 2167 /* Fill in the new prog array */ 2168 if (carry_prog_cnt) { 2169 existing = old_array->items; 2170 for (; existing->prog; existing++) { 2171 if (existing->prog == exclude_prog || 2172 existing->prog == &dummy_bpf_prog.prog) 2173 continue; 2174 2175 new->prog = existing->prog; 2176 new->bpf_cookie = existing->bpf_cookie; 2177 new++; 2178 } 2179 } 2180 if (include_prog) { 2181 new->prog = include_prog; 2182 new->bpf_cookie = bpf_cookie; 2183 new++; 2184 } 2185 new->prog = NULL; 2186 *new_array = array; 2187 return 0; 2188 } 2189 2190 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2191 u32 *prog_ids, u32 request_cnt, 2192 u32 *prog_cnt) 2193 { 2194 u32 cnt = 0; 2195 2196 if (array) 2197 cnt = bpf_prog_array_length(array); 2198 2199 *prog_cnt = cnt; 2200 2201 /* return early if user requested only program count or nothing to copy */ 2202 if (!request_cnt || !cnt) 2203 return 0; 2204 2205 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2206 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2207 : 0; 2208 } 2209 2210 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2211 struct bpf_map **used_maps, u32 len) 2212 { 2213 struct bpf_map *map; 2214 u32 i; 2215 2216 for (i = 0; i < len; i++) { 2217 map = used_maps[i]; 2218 if (map->ops->map_poke_untrack) 2219 map->ops->map_poke_untrack(map, aux); 2220 bpf_map_put(map); 2221 } 2222 } 2223 2224 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2225 { 2226 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2227 kfree(aux->used_maps); 2228 } 2229 2230 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2231 struct btf_mod_pair *used_btfs, u32 len) 2232 { 2233 #ifdef CONFIG_BPF_SYSCALL 2234 struct btf_mod_pair *btf_mod; 2235 u32 i; 2236 2237 for (i = 0; i < len; i++) { 2238 btf_mod = &used_btfs[i]; 2239 if (btf_mod->module) 2240 module_put(btf_mod->module); 2241 btf_put(btf_mod->btf); 2242 } 2243 #endif 2244 } 2245 2246 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2247 { 2248 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2249 kfree(aux->used_btfs); 2250 } 2251 2252 static void bpf_prog_free_deferred(struct work_struct *work) 2253 { 2254 struct bpf_prog_aux *aux; 2255 int i; 2256 2257 aux = container_of(work, struct bpf_prog_aux, work); 2258 bpf_free_used_maps(aux); 2259 bpf_free_used_btfs(aux); 2260 if (bpf_prog_is_dev_bound(aux)) 2261 bpf_prog_offload_destroy(aux->prog); 2262 #ifdef CONFIG_PERF_EVENTS 2263 if (aux->prog->has_callchain_buf) 2264 put_callchain_buffers(); 2265 #endif 2266 if (aux->dst_trampoline) 2267 bpf_trampoline_put(aux->dst_trampoline); 2268 for (i = 0; i < aux->func_cnt; i++) { 2269 /* We can just unlink the subprog poke descriptor table as 2270 * it was originally linked to the main program and is also 2271 * released along with it. 2272 */ 2273 aux->func[i]->aux->poke_tab = NULL; 2274 bpf_jit_free(aux->func[i]); 2275 } 2276 if (aux->func_cnt) { 2277 kfree(aux->func); 2278 bpf_prog_unlock_free(aux->prog); 2279 } else { 2280 bpf_jit_free(aux->prog); 2281 } 2282 } 2283 2284 /* Free internal BPF program */ 2285 void bpf_prog_free(struct bpf_prog *fp) 2286 { 2287 struct bpf_prog_aux *aux = fp->aux; 2288 2289 if (aux->dst_prog) 2290 bpf_prog_put(aux->dst_prog); 2291 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2292 schedule_work(&aux->work); 2293 } 2294 EXPORT_SYMBOL_GPL(bpf_prog_free); 2295 2296 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2297 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2298 2299 void bpf_user_rnd_init_once(void) 2300 { 2301 prandom_init_once(&bpf_user_rnd_state); 2302 } 2303 2304 BPF_CALL_0(bpf_user_rnd_u32) 2305 { 2306 /* Should someone ever have the rather unwise idea to use some 2307 * of the registers passed into this function, then note that 2308 * this function is called from native eBPF and classic-to-eBPF 2309 * transformations. Register assignments from both sides are 2310 * different, f.e. classic always sets fn(ctx, A, X) here. 2311 */ 2312 struct rnd_state *state; 2313 u32 res; 2314 2315 state = &get_cpu_var(bpf_user_rnd_state); 2316 res = prandom_u32_state(state); 2317 put_cpu_var(bpf_user_rnd_state); 2318 2319 return res; 2320 } 2321 2322 BPF_CALL_0(bpf_get_raw_cpu_id) 2323 { 2324 return raw_smp_processor_id(); 2325 } 2326 2327 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2328 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2329 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2330 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2331 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2332 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2333 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2334 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2335 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2336 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2337 2338 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2339 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2340 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2341 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2342 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2343 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2344 2345 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2346 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2347 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2348 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2349 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2350 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2351 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2352 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2353 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2354 2355 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2356 { 2357 return NULL; 2358 } 2359 2360 u64 __weak 2361 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2362 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2363 { 2364 return -ENOTSUPP; 2365 } 2366 EXPORT_SYMBOL_GPL(bpf_event_output); 2367 2368 /* Always built-in helper functions. */ 2369 const struct bpf_func_proto bpf_tail_call_proto = { 2370 .func = NULL, 2371 .gpl_only = false, 2372 .ret_type = RET_VOID, 2373 .arg1_type = ARG_PTR_TO_CTX, 2374 .arg2_type = ARG_CONST_MAP_PTR, 2375 .arg3_type = ARG_ANYTHING, 2376 }; 2377 2378 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2379 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2380 * eBPF and implicitly also cBPF can get JITed! 2381 */ 2382 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2383 { 2384 return prog; 2385 } 2386 2387 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2388 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2389 */ 2390 void __weak bpf_jit_compile(struct bpf_prog *prog) 2391 { 2392 } 2393 2394 bool __weak bpf_helper_changes_pkt_data(void *func) 2395 { 2396 return false; 2397 } 2398 2399 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2400 * analysis code and wants explicit zero extension inserted by verifier. 2401 * Otherwise, return FALSE. 2402 * 2403 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2404 * you don't override this. JITs that don't want these extra insns can detect 2405 * them using insn_is_zext. 2406 */ 2407 bool __weak bpf_jit_needs_zext(void) 2408 { 2409 return false; 2410 } 2411 2412 bool __weak bpf_jit_supports_kfunc_call(void) 2413 { 2414 return false; 2415 } 2416 2417 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2418 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2419 */ 2420 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2421 int len) 2422 { 2423 return -EFAULT; 2424 } 2425 2426 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2427 void *addr1, void *addr2) 2428 { 2429 return -ENOTSUPP; 2430 } 2431 2432 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2433 EXPORT_SYMBOL(bpf_stats_enabled_key); 2434 2435 /* All definitions of tracepoints related to BPF. */ 2436 #define CREATE_TRACE_POINTS 2437 #include <linux/bpf_trace.h> 2438 2439 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2440 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2441