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 #include <linux/bpf_verifier.h> 36 #include <linux/nodemask.h> 37 38 #include <asm/barrier.h> 39 #include <asm/unaligned.h> 40 41 /* Registers */ 42 #define BPF_R0 regs[BPF_REG_0] 43 #define BPF_R1 regs[BPF_REG_1] 44 #define BPF_R2 regs[BPF_REG_2] 45 #define BPF_R3 regs[BPF_REG_3] 46 #define BPF_R4 regs[BPF_REG_4] 47 #define BPF_R5 regs[BPF_REG_5] 48 #define BPF_R6 regs[BPF_REG_6] 49 #define BPF_R7 regs[BPF_REG_7] 50 #define BPF_R8 regs[BPF_REG_8] 51 #define BPF_R9 regs[BPF_REG_9] 52 #define BPF_R10 regs[BPF_REG_10] 53 54 /* Named registers */ 55 #define DST regs[insn->dst_reg] 56 #define SRC regs[insn->src_reg] 57 #define FP regs[BPF_REG_FP] 58 #define AX regs[BPF_REG_AX] 59 #define ARG1 regs[BPF_REG_ARG1] 60 #define CTX regs[BPF_REG_CTX] 61 #define IMM insn->imm 62 63 /* No hurry in this branch 64 * 65 * Exported for the bpf jit load helper. 66 */ 67 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 68 { 69 u8 *ptr = NULL; 70 71 if (k >= SKF_NET_OFF) { 72 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 73 } else if (k >= SKF_LL_OFF) { 74 if (unlikely(!skb_mac_header_was_set(skb))) 75 return NULL; 76 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 77 } 78 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 79 return ptr; 80 81 return NULL; 82 } 83 84 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 85 { 86 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 87 struct bpf_prog_aux *aux; 88 struct bpf_prog *fp; 89 90 size = round_up(size, PAGE_SIZE); 91 fp = __vmalloc(size, gfp_flags); 92 if (fp == NULL) 93 return NULL; 94 95 aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT | gfp_extra_flags); 96 if (aux == NULL) { 97 vfree(fp); 98 return NULL; 99 } 100 fp->active = alloc_percpu_gfp(int, GFP_KERNEL_ACCOUNT | gfp_extra_flags); 101 if (!fp->active) { 102 vfree(fp); 103 kfree(aux); 104 return NULL; 105 } 106 107 fp->pages = size / PAGE_SIZE; 108 fp->aux = aux; 109 fp->aux->prog = fp; 110 fp->jit_requested = ebpf_jit_enabled(); 111 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 112 #ifdef CONFIG_CGROUP_BPF 113 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 114 #endif 115 116 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 117 mutex_init(&fp->aux->used_maps_mutex); 118 mutex_init(&fp->aux->dst_mutex); 119 120 return fp; 121 } 122 123 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 124 { 125 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 126 struct bpf_prog *prog; 127 int cpu; 128 129 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 130 if (!prog) 131 return NULL; 132 133 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 134 if (!prog->stats) { 135 free_percpu(prog->active); 136 kfree(prog->aux); 137 vfree(prog); 138 return NULL; 139 } 140 141 for_each_possible_cpu(cpu) { 142 struct bpf_prog_stats *pstats; 143 144 pstats = per_cpu_ptr(prog->stats, cpu); 145 u64_stats_init(&pstats->syncp); 146 } 147 return prog; 148 } 149 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 150 151 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 152 { 153 if (!prog->aux->nr_linfo || !prog->jit_requested) 154 return 0; 155 156 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 157 sizeof(*prog->aux->jited_linfo), 158 GFP_KERNEL_ACCOUNT | __GFP_NOWARN); 159 if (!prog->aux->jited_linfo) 160 return -ENOMEM; 161 162 return 0; 163 } 164 165 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 166 { 167 if (prog->aux->jited_linfo && 168 (!prog->jited || !prog->aux->jited_linfo[0])) { 169 kvfree(prog->aux->jited_linfo); 170 prog->aux->jited_linfo = NULL; 171 } 172 173 kfree(prog->aux->kfunc_tab); 174 prog->aux->kfunc_tab = NULL; 175 } 176 177 /* The jit engine is responsible to provide an array 178 * for insn_off to the jited_off mapping (insn_to_jit_off). 179 * 180 * The idx to this array is the insn_off. Hence, the insn_off 181 * here is relative to the prog itself instead of the main prog. 182 * This array has one entry for each xlated bpf insn. 183 * 184 * jited_off is the byte off to the end of the jited insn. 185 * 186 * Hence, with 187 * insn_start: 188 * The first bpf insn off of the prog. The insn off 189 * here is relative to the main prog. 190 * e.g. if prog is a subprog, insn_start > 0 191 * linfo_idx: 192 * The prog's idx to prog->aux->linfo and jited_linfo 193 * 194 * jited_linfo[linfo_idx] = prog->bpf_func 195 * 196 * For i > linfo_idx, 197 * 198 * jited_linfo[i] = prog->bpf_func + 199 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 200 */ 201 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 202 const u32 *insn_to_jit_off) 203 { 204 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 205 const struct bpf_line_info *linfo; 206 void **jited_linfo; 207 208 if (!prog->aux->jited_linfo) 209 /* Userspace did not provide linfo */ 210 return; 211 212 linfo_idx = prog->aux->linfo_idx; 213 linfo = &prog->aux->linfo[linfo_idx]; 214 insn_start = linfo[0].insn_off; 215 insn_end = insn_start + prog->len; 216 217 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 218 jited_linfo[0] = prog->bpf_func; 219 220 nr_linfo = prog->aux->nr_linfo - linfo_idx; 221 222 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 223 /* The verifier ensures that linfo[i].insn_off is 224 * strictly increasing 225 */ 226 jited_linfo[i] = prog->bpf_func + 227 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 228 } 229 230 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 231 gfp_t gfp_extra_flags) 232 { 233 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 234 struct bpf_prog *fp; 235 u32 pages; 236 237 size = round_up(size, PAGE_SIZE); 238 pages = size / PAGE_SIZE; 239 if (pages <= fp_old->pages) 240 return fp_old; 241 242 fp = __vmalloc(size, gfp_flags); 243 if (fp) { 244 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 245 fp->pages = pages; 246 fp->aux->prog = fp; 247 248 /* We keep fp->aux from fp_old around in the new 249 * reallocated structure. 250 */ 251 fp_old->aux = NULL; 252 fp_old->stats = NULL; 253 fp_old->active = NULL; 254 __bpf_prog_free(fp_old); 255 } 256 257 return fp; 258 } 259 260 void __bpf_prog_free(struct bpf_prog *fp) 261 { 262 if (fp->aux) { 263 mutex_destroy(&fp->aux->used_maps_mutex); 264 mutex_destroy(&fp->aux->dst_mutex); 265 kfree(fp->aux->poke_tab); 266 kfree(fp->aux); 267 } 268 free_percpu(fp->stats); 269 free_percpu(fp->active); 270 vfree(fp); 271 } 272 273 int bpf_prog_calc_tag(struct bpf_prog *fp) 274 { 275 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 276 u32 raw_size = bpf_prog_tag_scratch_size(fp); 277 u32 digest[SHA1_DIGEST_WORDS]; 278 u32 ws[SHA1_WORKSPACE_WORDS]; 279 u32 i, bsize, psize, blocks; 280 struct bpf_insn *dst; 281 bool was_ld_map; 282 u8 *raw, *todo; 283 __be32 *result; 284 __be64 *bits; 285 286 raw = vmalloc(raw_size); 287 if (!raw) 288 return -ENOMEM; 289 290 sha1_init(digest); 291 memset(ws, 0, sizeof(ws)); 292 293 /* We need to take out the map fd for the digest calculation 294 * since they are unstable from user space side. 295 */ 296 dst = (void *)raw; 297 for (i = 0, was_ld_map = false; i < fp->len; i++) { 298 dst[i] = fp->insnsi[i]; 299 if (!was_ld_map && 300 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 301 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 302 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 303 was_ld_map = true; 304 dst[i].imm = 0; 305 } else if (was_ld_map && 306 dst[i].code == 0 && 307 dst[i].dst_reg == 0 && 308 dst[i].src_reg == 0 && 309 dst[i].off == 0) { 310 was_ld_map = false; 311 dst[i].imm = 0; 312 } else { 313 was_ld_map = false; 314 } 315 } 316 317 psize = bpf_prog_insn_size(fp); 318 memset(&raw[psize], 0, raw_size - psize); 319 raw[psize++] = 0x80; 320 321 bsize = round_up(psize, SHA1_BLOCK_SIZE); 322 blocks = bsize / SHA1_BLOCK_SIZE; 323 todo = raw; 324 if (bsize - psize >= sizeof(__be64)) { 325 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 326 } else { 327 bits = (__be64 *)(todo + bsize + bits_offset); 328 blocks++; 329 } 330 *bits = cpu_to_be64((psize - 1) << 3); 331 332 while (blocks--) { 333 sha1_transform(digest, todo, ws); 334 todo += SHA1_BLOCK_SIZE; 335 } 336 337 result = (__force __be32 *)digest; 338 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 339 result[i] = cpu_to_be32(digest[i]); 340 memcpy(fp->tag, result, sizeof(fp->tag)); 341 342 vfree(raw); 343 return 0; 344 } 345 346 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 347 s32 end_new, s32 curr, const bool probe_pass) 348 { 349 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 350 s32 delta = end_new - end_old; 351 s64 imm = insn->imm; 352 353 if (curr < pos && curr + imm + 1 >= end_old) 354 imm += delta; 355 else if (curr >= end_new && curr + imm + 1 < end_new) 356 imm -= delta; 357 if (imm < imm_min || imm > imm_max) 358 return -ERANGE; 359 if (!probe_pass) 360 insn->imm = imm; 361 return 0; 362 } 363 364 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 365 s32 end_new, s32 curr, const bool probe_pass) 366 { 367 const s32 off_min = S16_MIN, off_max = S16_MAX; 368 s32 delta = end_new - end_old; 369 s32 off = insn->off; 370 371 if (curr < pos && curr + off + 1 >= end_old) 372 off += delta; 373 else if (curr >= end_new && curr + off + 1 < end_new) 374 off -= delta; 375 if (off < off_min || off > off_max) 376 return -ERANGE; 377 if (!probe_pass) 378 insn->off = off; 379 return 0; 380 } 381 382 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 383 s32 end_new, const bool probe_pass) 384 { 385 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 386 struct bpf_insn *insn = prog->insnsi; 387 int ret = 0; 388 389 for (i = 0; i < insn_cnt; i++, insn++) { 390 u8 code; 391 392 /* In the probing pass we still operate on the original, 393 * unpatched image in order to check overflows before we 394 * do any other adjustments. Therefore skip the patchlet. 395 */ 396 if (probe_pass && i == pos) { 397 i = end_new; 398 insn = prog->insnsi + end_old; 399 } 400 if (bpf_pseudo_func(insn)) { 401 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 402 end_new, i, probe_pass); 403 if (ret) 404 return ret; 405 continue; 406 } 407 code = insn->code; 408 if ((BPF_CLASS(code) != BPF_JMP && 409 BPF_CLASS(code) != BPF_JMP32) || 410 BPF_OP(code) == BPF_EXIT) 411 continue; 412 /* Adjust offset of jmps if we cross patch boundaries. */ 413 if (BPF_OP(code) == BPF_CALL) { 414 if (insn->src_reg != BPF_PSEUDO_CALL) 415 continue; 416 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 417 end_new, i, probe_pass); 418 } else { 419 ret = bpf_adj_delta_to_off(insn, pos, end_old, 420 end_new, i, probe_pass); 421 } 422 if (ret) 423 break; 424 } 425 426 return ret; 427 } 428 429 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 430 { 431 struct bpf_line_info *linfo; 432 u32 i, nr_linfo; 433 434 nr_linfo = prog->aux->nr_linfo; 435 if (!nr_linfo || !delta) 436 return; 437 438 linfo = prog->aux->linfo; 439 440 for (i = 0; i < nr_linfo; i++) 441 if (off < linfo[i].insn_off) 442 break; 443 444 /* Push all off < linfo[i].insn_off by delta */ 445 for (; i < nr_linfo; i++) 446 linfo[i].insn_off += delta; 447 } 448 449 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 450 const struct bpf_insn *patch, u32 len) 451 { 452 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 453 const u32 cnt_max = S16_MAX; 454 struct bpf_prog *prog_adj; 455 int err; 456 457 /* Since our patchlet doesn't expand the image, we're done. */ 458 if (insn_delta == 0) { 459 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 460 return prog; 461 } 462 463 insn_adj_cnt = prog->len + insn_delta; 464 465 /* Reject anything that would potentially let the insn->off 466 * target overflow when we have excessive program expansions. 467 * We need to probe here before we do any reallocation where 468 * we afterwards may not fail anymore. 469 */ 470 if (insn_adj_cnt > cnt_max && 471 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 472 return ERR_PTR(err); 473 474 /* Several new instructions need to be inserted. Make room 475 * for them. Likely, there's no need for a new allocation as 476 * last page could have large enough tailroom. 477 */ 478 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 479 GFP_USER); 480 if (!prog_adj) 481 return ERR_PTR(-ENOMEM); 482 483 prog_adj->len = insn_adj_cnt; 484 485 /* Patching happens in 3 steps: 486 * 487 * 1) Move over tail of insnsi from next instruction onwards, 488 * so we can patch the single target insn with one or more 489 * new ones (patching is always from 1 to n insns, n > 0). 490 * 2) Inject new instructions at the target location. 491 * 3) Adjust branch offsets if necessary. 492 */ 493 insn_rest = insn_adj_cnt - off - len; 494 495 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 496 sizeof(*patch) * insn_rest); 497 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 498 499 /* We are guaranteed to not fail at this point, otherwise 500 * the ship has sailed to reverse to the original state. An 501 * overflow cannot happen at this point. 502 */ 503 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 504 505 bpf_adj_linfo(prog_adj, off, insn_delta); 506 507 return prog_adj; 508 } 509 510 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 511 { 512 /* Branch offsets can't overflow when program is shrinking, no need 513 * to call bpf_adj_branches(..., true) here 514 */ 515 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 516 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 517 prog->len -= cnt; 518 519 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 520 } 521 522 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 523 { 524 int i; 525 526 for (i = 0; i < fp->aux->func_cnt; i++) 527 bpf_prog_kallsyms_del(fp->aux->func[i]); 528 } 529 530 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 531 { 532 bpf_prog_kallsyms_del_subprogs(fp); 533 bpf_prog_kallsyms_del(fp); 534 } 535 536 #ifdef CONFIG_BPF_JIT 537 /* All BPF JIT sysctl knobs here. */ 538 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 539 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 540 int bpf_jit_harden __read_mostly; 541 long bpf_jit_limit __read_mostly; 542 long bpf_jit_limit_max __read_mostly; 543 544 static void 545 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 546 { 547 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 548 549 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 550 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 551 } 552 553 static void 554 bpf_prog_ksym_set_name(struct bpf_prog *prog) 555 { 556 char *sym = prog->aux->ksym.name; 557 const char *end = sym + KSYM_NAME_LEN; 558 const struct btf_type *type; 559 const char *func_name; 560 561 BUILD_BUG_ON(sizeof("bpf_prog_") + 562 sizeof(prog->tag) * 2 + 563 /* name has been null terminated. 564 * We should need +1 for the '_' preceding 565 * the name. However, the null character 566 * is double counted between the name and the 567 * sizeof("bpf_prog_") above, so we omit 568 * the +1 here. 569 */ 570 sizeof(prog->aux->name) > KSYM_NAME_LEN); 571 572 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 573 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 574 575 /* prog->aux->name will be ignored if full btf name is available */ 576 if (prog->aux->func_info_cnt) { 577 type = btf_type_by_id(prog->aux->btf, 578 prog->aux->func_info[prog->aux->func_idx].type_id); 579 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 580 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 581 return; 582 } 583 584 if (prog->aux->name[0]) 585 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 586 else 587 *sym = 0; 588 } 589 590 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 591 { 592 return container_of(n, struct bpf_ksym, tnode)->start; 593 } 594 595 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 596 struct latch_tree_node *b) 597 { 598 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 599 } 600 601 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 602 { 603 unsigned long val = (unsigned long)key; 604 const struct bpf_ksym *ksym; 605 606 ksym = container_of(n, struct bpf_ksym, tnode); 607 608 if (val < ksym->start) 609 return -1; 610 if (val >= ksym->end) 611 return 1; 612 613 return 0; 614 } 615 616 static const struct latch_tree_ops bpf_tree_ops = { 617 .less = bpf_tree_less, 618 .comp = bpf_tree_comp, 619 }; 620 621 static DEFINE_SPINLOCK(bpf_lock); 622 static LIST_HEAD(bpf_kallsyms); 623 static struct latch_tree_root bpf_tree __cacheline_aligned; 624 625 void bpf_ksym_add(struct bpf_ksym *ksym) 626 { 627 spin_lock_bh(&bpf_lock); 628 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 629 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 630 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 631 spin_unlock_bh(&bpf_lock); 632 } 633 634 static void __bpf_ksym_del(struct bpf_ksym *ksym) 635 { 636 if (list_empty(&ksym->lnode)) 637 return; 638 639 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 640 list_del_rcu(&ksym->lnode); 641 } 642 643 void bpf_ksym_del(struct bpf_ksym *ksym) 644 { 645 spin_lock_bh(&bpf_lock); 646 __bpf_ksym_del(ksym); 647 spin_unlock_bh(&bpf_lock); 648 } 649 650 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 651 { 652 return fp->jited && !bpf_prog_was_classic(fp); 653 } 654 655 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 656 { 657 if (!bpf_prog_kallsyms_candidate(fp) || 658 !bpf_capable()) 659 return; 660 661 bpf_prog_ksym_set_addr(fp); 662 bpf_prog_ksym_set_name(fp); 663 fp->aux->ksym.prog = true; 664 665 bpf_ksym_add(&fp->aux->ksym); 666 } 667 668 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 669 { 670 if (!bpf_prog_kallsyms_candidate(fp)) 671 return; 672 673 bpf_ksym_del(&fp->aux->ksym); 674 } 675 676 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 677 { 678 struct latch_tree_node *n; 679 680 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 681 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 682 } 683 684 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 685 unsigned long *off, char *sym) 686 { 687 struct bpf_ksym *ksym; 688 char *ret = NULL; 689 690 rcu_read_lock(); 691 ksym = bpf_ksym_find(addr); 692 if (ksym) { 693 unsigned long symbol_start = ksym->start; 694 unsigned long symbol_end = ksym->end; 695 696 strncpy(sym, ksym->name, KSYM_NAME_LEN); 697 698 ret = sym; 699 if (size) 700 *size = symbol_end - symbol_start; 701 if (off) 702 *off = addr - symbol_start; 703 } 704 rcu_read_unlock(); 705 706 return ret; 707 } 708 709 bool is_bpf_text_address(unsigned long addr) 710 { 711 bool ret; 712 713 rcu_read_lock(); 714 ret = bpf_ksym_find(addr) != NULL; 715 rcu_read_unlock(); 716 717 return ret; 718 } 719 720 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 721 { 722 struct bpf_ksym *ksym = bpf_ksym_find(addr); 723 724 return ksym && ksym->prog ? 725 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 726 NULL; 727 } 728 729 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 730 { 731 const struct exception_table_entry *e = NULL; 732 struct bpf_prog *prog; 733 734 rcu_read_lock(); 735 prog = bpf_prog_ksym_find(addr); 736 if (!prog) 737 goto out; 738 if (!prog->aux->num_exentries) 739 goto out; 740 741 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 742 out: 743 rcu_read_unlock(); 744 return e; 745 } 746 747 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 748 char *sym) 749 { 750 struct bpf_ksym *ksym; 751 unsigned int it = 0; 752 int ret = -ERANGE; 753 754 if (!bpf_jit_kallsyms_enabled()) 755 return ret; 756 757 rcu_read_lock(); 758 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 759 if (it++ != symnum) 760 continue; 761 762 strncpy(sym, ksym->name, KSYM_NAME_LEN); 763 764 *value = ksym->start; 765 *type = BPF_SYM_ELF_TYPE; 766 767 ret = 0; 768 break; 769 } 770 rcu_read_unlock(); 771 772 return ret; 773 } 774 775 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 776 struct bpf_jit_poke_descriptor *poke) 777 { 778 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 779 static const u32 poke_tab_max = 1024; 780 u32 slot = prog->aux->size_poke_tab; 781 u32 size = slot + 1; 782 783 if (size > poke_tab_max) 784 return -ENOSPC; 785 if (poke->tailcall_target || poke->tailcall_target_stable || 786 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 787 return -EINVAL; 788 789 switch (poke->reason) { 790 case BPF_POKE_REASON_TAIL_CALL: 791 if (!poke->tail_call.map) 792 return -EINVAL; 793 break; 794 default: 795 return -EINVAL; 796 } 797 798 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 799 if (!tab) 800 return -ENOMEM; 801 802 memcpy(&tab[slot], poke, sizeof(*poke)); 803 prog->aux->size_poke_tab = size; 804 prog->aux->poke_tab = tab; 805 806 return slot; 807 } 808 809 /* 810 * BPF program pack allocator. 811 * 812 * Most BPF programs are pretty small. Allocating a hole page for each 813 * program is sometime a waste. Many small bpf program also adds pressure 814 * to instruction TLB. To solve this issue, we introduce a BPF program pack 815 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 816 * to host BPF programs. 817 */ 818 #define BPF_PROG_CHUNK_SHIFT 6 819 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 820 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 821 822 struct bpf_prog_pack { 823 struct list_head list; 824 void *ptr; 825 unsigned long bitmap[]; 826 }; 827 828 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) 829 { 830 memset(area, 0, size); 831 } 832 833 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 834 835 static DEFINE_MUTEX(pack_mutex); 836 static LIST_HEAD(pack_list); 837 838 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 839 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 840 */ 841 #ifdef PMD_SIZE 842 #define BPF_PROG_PACK_SIZE (PMD_SIZE * num_possible_nodes()) 843 #else 844 #define BPF_PROG_PACK_SIZE PAGE_SIZE 845 #endif 846 847 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 848 849 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 850 { 851 struct bpf_prog_pack *pack; 852 853 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), 854 GFP_KERNEL); 855 if (!pack) 856 return NULL; 857 pack->ptr = module_alloc(BPF_PROG_PACK_SIZE); 858 if (!pack->ptr) { 859 kfree(pack); 860 return NULL; 861 } 862 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 863 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 864 list_add_tail(&pack->list, &pack_list); 865 866 set_vm_flush_reset_perms(pack->ptr); 867 set_memory_ro((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 868 set_memory_x((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 869 return pack; 870 } 871 872 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 873 { 874 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 875 struct bpf_prog_pack *pack; 876 unsigned long pos; 877 void *ptr = NULL; 878 879 mutex_lock(&pack_mutex); 880 if (size > BPF_PROG_PACK_SIZE) { 881 size = round_up(size, PAGE_SIZE); 882 ptr = module_alloc(size); 883 if (ptr) { 884 bpf_fill_ill_insns(ptr, size); 885 set_vm_flush_reset_perms(ptr); 886 set_memory_ro((unsigned long)ptr, size / PAGE_SIZE); 887 set_memory_x((unsigned long)ptr, size / PAGE_SIZE); 888 } 889 goto out; 890 } 891 list_for_each_entry(pack, &pack_list, list) { 892 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 893 nbits, 0); 894 if (pos < BPF_PROG_CHUNK_COUNT) 895 goto found_free_area; 896 } 897 898 pack = alloc_new_pack(bpf_fill_ill_insns); 899 if (!pack) 900 goto out; 901 902 pos = 0; 903 904 found_free_area: 905 bitmap_set(pack->bitmap, pos, nbits); 906 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 907 908 out: 909 mutex_unlock(&pack_mutex); 910 return ptr; 911 } 912 913 void bpf_prog_pack_free(struct bpf_binary_header *hdr) 914 { 915 struct bpf_prog_pack *pack = NULL, *tmp; 916 unsigned int nbits; 917 unsigned long pos; 918 919 mutex_lock(&pack_mutex); 920 if (hdr->size > BPF_PROG_PACK_SIZE) { 921 module_memfree(hdr); 922 goto out; 923 } 924 925 list_for_each_entry(tmp, &pack_list, list) { 926 if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) { 927 pack = tmp; 928 break; 929 } 930 } 931 932 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 933 goto out; 934 935 nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size); 936 pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; 937 938 WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size), 939 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 940 941 bitmap_clear(pack->bitmap, pos, nbits); 942 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 943 BPF_PROG_CHUNK_COUNT, 0) == 0) { 944 list_del(&pack->list); 945 module_memfree(pack->ptr); 946 kfree(pack); 947 } 948 out: 949 mutex_unlock(&pack_mutex); 950 } 951 952 static atomic_long_t bpf_jit_current; 953 954 /* Can be overridden by an arch's JIT compiler if it has a custom, 955 * dedicated BPF backend memory area, or if neither of the two 956 * below apply. 957 */ 958 u64 __weak bpf_jit_alloc_exec_limit(void) 959 { 960 #if defined(MODULES_VADDR) 961 return MODULES_END - MODULES_VADDR; 962 #else 963 return VMALLOC_END - VMALLOC_START; 964 #endif 965 } 966 967 static int __init bpf_jit_charge_init(void) 968 { 969 /* Only used as heuristic here to derive limit. */ 970 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 971 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2, 972 PAGE_SIZE), LONG_MAX); 973 return 0; 974 } 975 pure_initcall(bpf_jit_charge_init); 976 977 int bpf_jit_charge_modmem(u32 size) 978 { 979 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { 980 if (!bpf_capable()) { 981 atomic_long_sub(size, &bpf_jit_current); 982 return -EPERM; 983 } 984 } 985 986 return 0; 987 } 988 989 void bpf_jit_uncharge_modmem(u32 size) 990 { 991 atomic_long_sub(size, &bpf_jit_current); 992 } 993 994 void *__weak bpf_jit_alloc_exec(unsigned long size) 995 { 996 return module_alloc(size); 997 } 998 999 void __weak bpf_jit_free_exec(void *addr) 1000 { 1001 module_memfree(addr); 1002 } 1003 1004 struct bpf_binary_header * 1005 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1006 unsigned int alignment, 1007 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1008 { 1009 struct bpf_binary_header *hdr; 1010 u32 size, hole, start; 1011 1012 WARN_ON_ONCE(!is_power_of_2(alignment) || 1013 alignment > BPF_IMAGE_ALIGNMENT); 1014 1015 /* Most of BPF filters are really small, but if some of them 1016 * fill a page, allow at least 128 extra bytes to insert a 1017 * random section of illegal instructions. 1018 */ 1019 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1020 1021 if (bpf_jit_charge_modmem(size)) 1022 return NULL; 1023 hdr = bpf_jit_alloc_exec(size); 1024 if (!hdr) { 1025 bpf_jit_uncharge_modmem(size); 1026 return NULL; 1027 } 1028 1029 /* Fill space with illegal/arch-dep instructions. */ 1030 bpf_fill_ill_insns(hdr, size); 1031 1032 hdr->size = size; 1033 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1034 PAGE_SIZE - sizeof(*hdr)); 1035 start = prandom_u32_max(hole) & ~(alignment - 1); 1036 1037 /* Leave a random number of instructions before BPF code. */ 1038 *image_ptr = &hdr->image[start]; 1039 1040 return hdr; 1041 } 1042 1043 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1044 { 1045 u32 size = hdr->size; 1046 1047 bpf_jit_free_exec(hdr); 1048 bpf_jit_uncharge_modmem(size); 1049 } 1050 1051 /* Allocate jit binary from bpf_prog_pack allocator. 1052 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1053 * to the memory. To solve this problem, a RW buffer is also allocated at 1054 * as the same time. The JIT engine should calculate offsets based on the 1055 * RO memory address, but write JITed program to the RW buffer. Once the 1056 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1057 * the JITed program to the RO memory. 1058 */ 1059 struct bpf_binary_header * 1060 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1061 unsigned int alignment, 1062 struct bpf_binary_header **rw_header, 1063 u8 **rw_image, 1064 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1065 { 1066 struct bpf_binary_header *ro_header; 1067 u32 size, hole, start; 1068 1069 WARN_ON_ONCE(!is_power_of_2(alignment) || 1070 alignment > BPF_IMAGE_ALIGNMENT); 1071 1072 /* add 16 bytes for a random section of illegal instructions */ 1073 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1074 1075 if (bpf_jit_charge_modmem(size)) 1076 return NULL; 1077 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1078 if (!ro_header) { 1079 bpf_jit_uncharge_modmem(size); 1080 return NULL; 1081 } 1082 1083 *rw_header = kvmalloc(size, GFP_KERNEL); 1084 if (!*rw_header) { 1085 bpf_arch_text_copy(&ro_header->size, &size, sizeof(size)); 1086 bpf_prog_pack_free(ro_header); 1087 bpf_jit_uncharge_modmem(size); 1088 return NULL; 1089 } 1090 1091 /* Fill space with illegal/arch-dep instructions. */ 1092 bpf_fill_ill_insns(*rw_header, size); 1093 (*rw_header)->size = size; 1094 1095 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1096 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1097 start = prandom_u32_max(hole) & ~(alignment - 1); 1098 1099 *image_ptr = &ro_header->image[start]; 1100 *rw_image = &(*rw_header)->image[start]; 1101 1102 return ro_header; 1103 } 1104 1105 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1106 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, 1107 struct bpf_binary_header *ro_header, 1108 struct bpf_binary_header *rw_header) 1109 { 1110 void *ptr; 1111 1112 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1113 1114 kvfree(rw_header); 1115 1116 if (IS_ERR(ptr)) { 1117 bpf_prog_pack_free(ro_header); 1118 return PTR_ERR(ptr); 1119 } 1120 return 0; 1121 } 1122 1123 /* bpf_jit_binary_pack_free is called in two different scenarios: 1124 * 1) when the program is freed after; 1125 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1126 * For case 2), we need to free both the RO memory and the RW buffer. 1127 * 1128 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1129 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1130 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1131 * bpf_arch_text_copy (when jit fails). 1132 */ 1133 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1134 struct bpf_binary_header *rw_header) 1135 { 1136 u32 size = ro_header->size; 1137 1138 bpf_prog_pack_free(ro_header); 1139 kvfree(rw_header); 1140 bpf_jit_uncharge_modmem(size); 1141 } 1142 1143 struct bpf_binary_header * 1144 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp) 1145 { 1146 unsigned long real_start = (unsigned long)fp->bpf_func; 1147 unsigned long addr; 1148 1149 addr = real_start & BPF_PROG_CHUNK_MASK; 1150 return (void *)addr; 1151 } 1152 1153 static inline struct bpf_binary_header * 1154 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1155 { 1156 unsigned long real_start = (unsigned long)fp->bpf_func; 1157 unsigned long addr; 1158 1159 addr = real_start & PAGE_MASK; 1160 return (void *)addr; 1161 } 1162 1163 /* This symbol is only overridden by archs that have different 1164 * requirements than the usual eBPF JITs, f.e. when they only 1165 * implement cBPF JIT, do not set images read-only, etc. 1166 */ 1167 void __weak bpf_jit_free(struct bpf_prog *fp) 1168 { 1169 if (fp->jited) { 1170 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1171 1172 bpf_jit_binary_free(hdr); 1173 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1174 } 1175 1176 bpf_prog_unlock_free(fp); 1177 } 1178 1179 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1180 const struct bpf_insn *insn, bool extra_pass, 1181 u64 *func_addr, bool *func_addr_fixed) 1182 { 1183 s16 off = insn->off; 1184 s32 imm = insn->imm; 1185 u8 *addr; 1186 1187 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1188 if (!*func_addr_fixed) { 1189 /* Place-holder address till the last pass has collected 1190 * all addresses for JITed subprograms in which case we 1191 * can pick them up from prog->aux. 1192 */ 1193 if (!extra_pass) 1194 addr = NULL; 1195 else if (prog->aux->func && 1196 off >= 0 && off < prog->aux->func_cnt) 1197 addr = (u8 *)prog->aux->func[off]->bpf_func; 1198 else 1199 return -EINVAL; 1200 } else { 1201 /* Address of a BPF helper call. Since part of the core 1202 * kernel, it's always at a fixed location. __bpf_call_base 1203 * and the helper with imm relative to it are both in core 1204 * kernel. 1205 */ 1206 addr = (u8 *)__bpf_call_base + imm; 1207 } 1208 1209 *func_addr = (unsigned long)addr; 1210 return 0; 1211 } 1212 1213 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1214 const struct bpf_insn *aux, 1215 struct bpf_insn *to_buff, 1216 bool emit_zext) 1217 { 1218 struct bpf_insn *to = to_buff; 1219 u32 imm_rnd = get_random_u32(); 1220 s16 off; 1221 1222 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1223 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1224 1225 /* Constraints on AX register: 1226 * 1227 * AX register is inaccessible from user space. It is mapped in 1228 * all JITs, and used here for constant blinding rewrites. It is 1229 * typically "stateless" meaning its contents are only valid within 1230 * the executed instruction, but not across several instructions. 1231 * There are a few exceptions however which are further detailed 1232 * below. 1233 * 1234 * Constant blinding is only used by JITs, not in the interpreter. 1235 * The interpreter uses AX in some occasions as a local temporary 1236 * register e.g. in DIV or MOD instructions. 1237 * 1238 * In restricted circumstances, the verifier can also use the AX 1239 * register for rewrites as long as they do not interfere with 1240 * the above cases! 1241 */ 1242 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1243 goto out; 1244 1245 if (from->imm == 0 && 1246 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1247 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1248 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1249 goto out; 1250 } 1251 1252 switch (from->code) { 1253 case BPF_ALU | BPF_ADD | BPF_K: 1254 case BPF_ALU | BPF_SUB | BPF_K: 1255 case BPF_ALU | BPF_AND | BPF_K: 1256 case BPF_ALU | BPF_OR | BPF_K: 1257 case BPF_ALU | BPF_XOR | BPF_K: 1258 case BPF_ALU | BPF_MUL | BPF_K: 1259 case BPF_ALU | BPF_MOV | BPF_K: 1260 case BPF_ALU | BPF_DIV | BPF_K: 1261 case BPF_ALU | BPF_MOD | BPF_K: 1262 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1263 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1264 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1265 break; 1266 1267 case BPF_ALU64 | BPF_ADD | BPF_K: 1268 case BPF_ALU64 | BPF_SUB | BPF_K: 1269 case BPF_ALU64 | BPF_AND | BPF_K: 1270 case BPF_ALU64 | BPF_OR | BPF_K: 1271 case BPF_ALU64 | BPF_XOR | BPF_K: 1272 case BPF_ALU64 | BPF_MUL | BPF_K: 1273 case BPF_ALU64 | BPF_MOV | BPF_K: 1274 case BPF_ALU64 | BPF_DIV | BPF_K: 1275 case BPF_ALU64 | BPF_MOD | BPF_K: 1276 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1277 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1278 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1279 break; 1280 1281 case BPF_JMP | BPF_JEQ | BPF_K: 1282 case BPF_JMP | BPF_JNE | BPF_K: 1283 case BPF_JMP | BPF_JGT | BPF_K: 1284 case BPF_JMP | BPF_JLT | BPF_K: 1285 case BPF_JMP | BPF_JGE | BPF_K: 1286 case BPF_JMP | BPF_JLE | BPF_K: 1287 case BPF_JMP | BPF_JSGT | BPF_K: 1288 case BPF_JMP | BPF_JSLT | BPF_K: 1289 case BPF_JMP | BPF_JSGE | BPF_K: 1290 case BPF_JMP | BPF_JSLE | BPF_K: 1291 case BPF_JMP | BPF_JSET | BPF_K: 1292 /* Accommodate for extra offset in case of a backjump. */ 1293 off = from->off; 1294 if (off < 0) 1295 off -= 2; 1296 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1297 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1298 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1299 break; 1300 1301 case BPF_JMP32 | BPF_JEQ | BPF_K: 1302 case BPF_JMP32 | BPF_JNE | BPF_K: 1303 case BPF_JMP32 | BPF_JGT | BPF_K: 1304 case BPF_JMP32 | BPF_JLT | BPF_K: 1305 case BPF_JMP32 | BPF_JGE | BPF_K: 1306 case BPF_JMP32 | BPF_JLE | BPF_K: 1307 case BPF_JMP32 | BPF_JSGT | BPF_K: 1308 case BPF_JMP32 | BPF_JSLT | BPF_K: 1309 case BPF_JMP32 | BPF_JSGE | BPF_K: 1310 case BPF_JMP32 | BPF_JSLE | BPF_K: 1311 case BPF_JMP32 | BPF_JSET | BPF_K: 1312 /* Accommodate for extra offset in case of a backjump. */ 1313 off = from->off; 1314 if (off < 0) 1315 off -= 2; 1316 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1317 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1318 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1319 off); 1320 break; 1321 1322 case BPF_LD | BPF_IMM | BPF_DW: 1323 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1324 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1325 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1326 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1327 break; 1328 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1329 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1330 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1331 if (emit_zext) 1332 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1333 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1334 break; 1335 1336 case BPF_ST | BPF_MEM | BPF_DW: 1337 case BPF_ST | BPF_MEM | BPF_W: 1338 case BPF_ST | BPF_MEM | BPF_H: 1339 case BPF_ST | BPF_MEM | BPF_B: 1340 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1341 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1342 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1343 break; 1344 } 1345 out: 1346 return to - to_buff; 1347 } 1348 1349 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1350 gfp_t gfp_extra_flags) 1351 { 1352 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1353 struct bpf_prog *fp; 1354 1355 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1356 if (fp != NULL) { 1357 /* aux->prog still points to the fp_other one, so 1358 * when promoting the clone to the real program, 1359 * this still needs to be adapted. 1360 */ 1361 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1362 } 1363 1364 return fp; 1365 } 1366 1367 static void bpf_prog_clone_free(struct bpf_prog *fp) 1368 { 1369 /* aux was stolen by the other clone, so we cannot free 1370 * it from this path! It will be freed eventually by the 1371 * other program on release. 1372 * 1373 * At this point, we don't need a deferred release since 1374 * clone is guaranteed to not be locked. 1375 */ 1376 fp->aux = NULL; 1377 fp->stats = NULL; 1378 fp->active = NULL; 1379 __bpf_prog_free(fp); 1380 } 1381 1382 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1383 { 1384 /* We have to repoint aux->prog to self, as we don't 1385 * know whether fp here is the clone or the original. 1386 */ 1387 fp->aux->prog = fp; 1388 bpf_prog_clone_free(fp_other); 1389 } 1390 1391 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1392 { 1393 struct bpf_insn insn_buff[16], aux[2]; 1394 struct bpf_prog *clone, *tmp; 1395 int insn_delta, insn_cnt; 1396 struct bpf_insn *insn; 1397 int i, rewritten; 1398 1399 if (!prog->blinding_requested || prog->blinded) 1400 return prog; 1401 1402 clone = bpf_prog_clone_create(prog, GFP_USER); 1403 if (!clone) 1404 return ERR_PTR(-ENOMEM); 1405 1406 insn_cnt = clone->len; 1407 insn = clone->insnsi; 1408 1409 for (i = 0; i < insn_cnt; i++, insn++) { 1410 if (bpf_pseudo_func(insn)) { 1411 /* ld_imm64 with an address of bpf subprog is not 1412 * a user controlled constant. Don't randomize it, 1413 * since it will conflict with jit_subprogs() logic. 1414 */ 1415 insn++; 1416 i++; 1417 continue; 1418 } 1419 1420 /* We temporarily need to hold the original ld64 insn 1421 * so that we can still access the first part in the 1422 * second blinding run. 1423 */ 1424 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1425 insn[1].code == 0) 1426 memcpy(aux, insn, sizeof(aux)); 1427 1428 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1429 clone->aux->verifier_zext); 1430 if (!rewritten) 1431 continue; 1432 1433 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1434 if (IS_ERR(tmp)) { 1435 /* Patching may have repointed aux->prog during 1436 * realloc from the original one, so we need to 1437 * fix it up here on error. 1438 */ 1439 bpf_jit_prog_release_other(prog, clone); 1440 return tmp; 1441 } 1442 1443 clone = tmp; 1444 insn_delta = rewritten - 1; 1445 1446 /* Walk new program and skip insns we just inserted. */ 1447 insn = clone->insnsi + i + insn_delta; 1448 insn_cnt += insn_delta; 1449 i += insn_delta; 1450 } 1451 1452 clone->blinded = 1; 1453 return clone; 1454 } 1455 #endif /* CONFIG_BPF_JIT */ 1456 1457 /* Base function for offset calculation. Needs to go into .text section, 1458 * therefore keeping it non-static as well; will also be used by JITs 1459 * anyway later on, so do not let the compiler omit it. This also needs 1460 * to go into kallsyms for correlation from e.g. bpftool, so naming 1461 * must not change. 1462 */ 1463 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1464 { 1465 return 0; 1466 } 1467 EXPORT_SYMBOL_GPL(__bpf_call_base); 1468 1469 /* All UAPI available opcodes. */ 1470 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1471 /* 32 bit ALU operations. */ \ 1472 /* Register based. */ \ 1473 INSN_3(ALU, ADD, X), \ 1474 INSN_3(ALU, SUB, X), \ 1475 INSN_3(ALU, AND, X), \ 1476 INSN_3(ALU, OR, X), \ 1477 INSN_3(ALU, LSH, X), \ 1478 INSN_3(ALU, RSH, X), \ 1479 INSN_3(ALU, XOR, X), \ 1480 INSN_3(ALU, MUL, X), \ 1481 INSN_3(ALU, MOV, X), \ 1482 INSN_3(ALU, ARSH, X), \ 1483 INSN_3(ALU, DIV, X), \ 1484 INSN_3(ALU, MOD, X), \ 1485 INSN_2(ALU, NEG), \ 1486 INSN_3(ALU, END, TO_BE), \ 1487 INSN_3(ALU, END, TO_LE), \ 1488 /* Immediate based. */ \ 1489 INSN_3(ALU, ADD, K), \ 1490 INSN_3(ALU, SUB, K), \ 1491 INSN_3(ALU, AND, K), \ 1492 INSN_3(ALU, OR, K), \ 1493 INSN_3(ALU, LSH, K), \ 1494 INSN_3(ALU, RSH, K), \ 1495 INSN_3(ALU, XOR, K), \ 1496 INSN_3(ALU, MUL, K), \ 1497 INSN_3(ALU, MOV, K), \ 1498 INSN_3(ALU, ARSH, K), \ 1499 INSN_3(ALU, DIV, K), \ 1500 INSN_3(ALU, MOD, K), \ 1501 /* 64 bit ALU operations. */ \ 1502 /* Register based. */ \ 1503 INSN_3(ALU64, ADD, X), \ 1504 INSN_3(ALU64, SUB, X), \ 1505 INSN_3(ALU64, AND, X), \ 1506 INSN_3(ALU64, OR, X), \ 1507 INSN_3(ALU64, LSH, X), \ 1508 INSN_3(ALU64, RSH, X), \ 1509 INSN_3(ALU64, XOR, X), \ 1510 INSN_3(ALU64, MUL, X), \ 1511 INSN_3(ALU64, MOV, X), \ 1512 INSN_3(ALU64, ARSH, X), \ 1513 INSN_3(ALU64, DIV, X), \ 1514 INSN_3(ALU64, MOD, X), \ 1515 INSN_2(ALU64, NEG), \ 1516 /* Immediate based. */ \ 1517 INSN_3(ALU64, ADD, K), \ 1518 INSN_3(ALU64, SUB, K), \ 1519 INSN_3(ALU64, AND, K), \ 1520 INSN_3(ALU64, OR, K), \ 1521 INSN_3(ALU64, LSH, K), \ 1522 INSN_3(ALU64, RSH, K), \ 1523 INSN_3(ALU64, XOR, K), \ 1524 INSN_3(ALU64, MUL, K), \ 1525 INSN_3(ALU64, MOV, K), \ 1526 INSN_3(ALU64, ARSH, K), \ 1527 INSN_3(ALU64, DIV, K), \ 1528 INSN_3(ALU64, MOD, K), \ 1529 /* Call instruction. */ \ 1530 INSN_2(JMP, CALL), \ 1531 /* Exit instruction. */ \ 1532 INSN_2(JMP, EXIT), \ 1533 /* 32-bit Jump instructions. */ \ 1534 /* Register based. */ \ 1535 INSN_3(JMP32, JEQ, X), \ 1536 INSN_3(JMP32, JNE, X), \ 1537 INSN_3(JMP32, JGT, X), \ 1538 INSN_3(JMP32, JLT, X), \ 1539 INSN_3(JMP32, JGE, X), \ 1540 INSN_3(JMP32, JLE, X), \ 1541 INSN_3(JMP32, JSGT, X), \ 1542 INSN_3(JMP32, JSLT, X), \ 1543 INSN_3(JMP32, JSGE, X), \ 1544 INSN_3(JMP32, JSLE, X), \ 1545 INSN_3(JMP32, JSET, X), \ 1546 /* Immediate based. */ \ 1547 INSN_3(JMP32, JEQ, K), \ 1548 INSN_3(JMP32, JNE, K), \ 1549 INSN_3(JMP32, JGT, K), \ 1550 INSN_3(JMP32, JLT, K), \ 1551 INSN_3(JMP32, JGE, K), \ 1552 INSN_3(JMP32, JLE, K), \ 1553 INSN_3(JMP32, JSGT, K), \ 1554 INSN_3(JMP32, JSLT, K), \ 1555 INSN_3(JMP32, JSGE, K), \ 1556 INSN_3(JMP32, JSLE, K), \ 1557 INSN_3(JMP32, JSET, K), \ 1558 /* Jump instructions. */ \ 1559 /* Register based. */ \ 1560 INSN_3(JMP, JEQ, X), \ 1561 INSN_3(JMP, JNE, X), \ 1562 INSN_3(JMP, JGT, X), \ 1563 INSN_3(JMP, JLT, X), \ 1564 INSN_3(JMP, JGE, X), \ 1565 INSN_3(JMP, JLE, X), \ 1566 INSN_3(JMP, JSGT, X), \ 1567 INSN_3(JMP, JSLT, X), \ 1568 INSN_3(JMP, JSGE, X), \ 1569 INSN_3(JMP, JSLE, X), \ 1570 INSN_3(JMP, JSET, X), \ 1571 /* Immediate based. */ \ 1572 INSN_3(JMP, JEQ, K), \ 1573 INSN_3(JMP, JNE, K), \ 1574 INSN_3(JMP, JGT, K), \ 1575 INSN_3(JMP, JLT, K), \ 1576 INSN_3(JMP, JGE, K), \ 1577 INSN_3(JMP, JLE, K), \ 1578 INSN_3(JMP, JSGT, K), \ 1579 INSN_3(JMP, JSLT, K), \ 1580 INSN_3(JMP, JSGE, K), \ 1581 INSN_3(JMP, JSLE, K), \ 1582 INSN_3(JMP, JSET, K), \ 1583 INSN_2(JMP, JA), \ 1584 /* Store instructions. */ \ 1585 /* Register based. */ \ 1586 INSN_3(STX, MEM, B), \ 1587 INSN_3(STX, MEM, H), \ 1588 INSN_3(STX, MEM, W), \ 1589 INSN_3(STX, MEM, DW), \ 1590 INSN_3(STX, ATOMIC, W), \ 1591 INSN_3(STX, ATOMIC, DW), \ 1592 /* Immediate based. */ \ 1593 INSN_3(ST, MEM, B), \ 1594 INSN_3(ST, MEM, H), \ 1595 INSN_3(ST, MEM, W), \ 1596 INSN_3(ST, MEM, DW), \ 1597 /* Load instructions. */ \ 1598 /* Register based. */ \ 1599 INSN_3(LDX, MEM, B), \ 1600 INSN_3(LDX, MEM, H), \ 1601 INSN_3(LDX, MEM, W), \ 1602 INSN_3(LDX, MEM, DW), \ 1603 /* Immediate based. */ \ 1604 INSN_3(LD, IMM, DW) 1605 1606 bool bpf_opcode_in_insntable(u8 code) 1607 { 1608 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1609 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1610 static const bool public_insntable[256] = { 1611 [0 ... 255] = false, 1612 /* Now overwrite non-defaults ... */ 1613 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1614 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1615 [BPF_LD | BPF_ABS | BPF_B] = true, 1616 [BPF_LD | BPF_ABS | BPF_H] = true, 1617 [BPF_LD | BPF_ABS | BPF_W] = true, 1618 [BPF_LD | BPF_IND | BPF_B] = true, 1619 [BPF_LD | BPF_IND | BPF_H] = true, 1620 [BPF_LD | BPF_IND | BPF_W] = true, 1621 }; 1622 #undef BPF_INSN_3_TBL 1623 #undef BPF_INSN_2_TBL 1624 return public_insntable[code]; 1625 } 1626 1627 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1628 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1629 { 1630 memset(dst, 0, size); 1631 return -EFAULT; 1632 } 1633 1634 /** 1635 * ___bpf_prog_run - run eBPF program on a given context 1636 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1637 * @insn: is the array of eBPF instructions 1638 * 1639 * Decode and execute eBPF instructions. 1640 * 1641 * Return: whatever value is in %BPF_R0 at program exit 1642 */ 1643 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1644 { 1645 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1646 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1647 static const void * const jumptable[256] __annotate_jump_table = { 1648 [0 ... 255] = &&default_label, 1649 /* Now overwrite non-defaults ... */ 1650 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1651 /* Non-UAPI available opcodes. */ 1652 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1653 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1654 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1655 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1656 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1657 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1658 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1659 }; 1660 #undef BPF_INSN_3_LBL 1661 #undef BPF_INSN_2_LBL 1662 u32 tail_call_cnt = 0; 1663 1664 #define CONT ({ insn++; goto select_insn; }) 1665 #define CONT_JMP ({ insn++; goto select_insn; }) 1666 1667 select_insn: 1668 goto *jumptable[insn->code]; 1669 1670 /* Explicitly mask the register-based shift amounts with 63 or 31 1671 * to avoid undefined behavior. Normally this won't affect the 1672 * generated code, for example, in case of native 64 bit archs such 1673 * as x86-64 or arm64, the compiler is optimizing the AND away for 1674 * the interpreter. In case of JITs, each of the JIT backends compiles 1675 * the BPF shift operations to machine instructions which produce 1676 * implementation-defined results in such a case; the resulting 1677 * contents of the register may be arbitrary, but program behaviour 1678 * as a whole remains defined. In other words, in case of JIT backends, 1679 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1680 */ 1681 /* ALU (shifts) */ 1682 #define SHT(OPCODE, OP) \ 1683 ALU64_##OPCODE##_X: \ 1684 DST = DST OP (SRC & 63); \ 1685 CONT; \ 1686 ALU_##OPCODE##_X: \ 1687 DST = (u32) DST OP ((u32) SRC & 31); \ 1688 CONT; \ 1689 ALU64_##OPCODE##_K: \ 1690 DST = DST OP IMM; \ 1691 CONT; \ 1692 ALU_##OPCODE##_K: \ 1693 DST = (u32) DST OP (u32) IMM; \ 1694 CONT; 1695 /* ALU (rest) */ 1696 #define ALU(OPCODE, OP) \ 1697 ALU64_##OPCODE##_X: \ 1698 DST = DST OP SRC; \ 1699 CONT; \ 1700 ALU_##OPCODE##_X: \ 1701 DST = (u32) DST OP (u32) SRC; \ 1702 CONT; \ 1703 ALU64_##OPCODE##_K: \ 1704 DST = DST OP IMM; \ 1705 CONT; \ 1706 ALU_##OPCODE##_K: \ 1707 DST = (u32) DST OP (u32) IMM; \ 1708 CONT; 1709 ALU(ADD, +) 1710 ALU(SUB, -) 1711 ALU(AND, &) 1712 ALU(OR, |) 1713 ALU(XOR, ^) 1714 ALU(MUL, *) 1715 SHT(LSH, <<) 1716 SHT(RSH, >>) 1717 #undef SHT 1718 #undef ALU 1719 ALU_NEG: 1720 DST = (u32) -DST; 1721 CONT; 1722 ALU64_NEG: 1723 DST = -DST; 1724 CONT; 1725 ALU_MOV_X: 1726 DST = (u32) SRC; 1727 CONT; 1728 ALU_MOV_K: 1729 DST = (u32) IMM; 1730 CONT; 1731 ALU64_MOV_X: 1732 DST = SRC; 1733 CONT; 1734 ALU64_MOV_K: 1735 DST = IMM; 1736 CONT; 1737 LD_IMM_DW: 1738 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1739 insn++; 1740 CONT; 1741 ALU_ARSH_X: 1742 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1743 CONT; 1744 ALU_ARSH_K: 1745 DST = (u64) (u32) (((s32) DST) >> IMM); 1746 CONT; 1747 ALU64_ARSH_X: 1748 (*(s64 *) &DST) >>= (SRC & 63); 1749 CONT; 1750 ALU64_ARSH_K: 1751 (*(s64 *) &DST) >>= IMM; 1752 CONT; 1753 ALU64_MOD_X: 1754 div64_u64_rem(DST, SRC, &AX); 1755 DST = AX; 1756 CONT; 1757 ALU_MOD_X: 1758 AX = (u32) DST; 1759 DST = do_div(AX, (u32) SRC); 1760 CONT; 1761 ALU64_MOD_K: 1762 div64_u64_rem(DST, IMM, &AX); 1763 DST = AX; 1764 CONT; 1765 ALU_MOD_K: 1766 AX = (u32) DST; 1767 DST = do_div(AX, (u32) IMM); 1768 CONT; 1769 ALU64_DIV_X: 1770 DST = div64_u64(DST, SRC); 1771 CONT; 1772 ALU_DIV_X: 1773 AX = (u32) DST; 1774 do_div(AX, (u32) SRC); 1775 DST = (u32) AX; 1776 CONT; 1777 ALU64_DIV_K: 1778 DST = div64_u64(DST, IMM); 1779 CONT; 1780 ALU_DIV_K: 1781 AX = (u32) DST; 1782 do_div(AX, (u32) IMM); 1783 DST = (u32) AX; 1784 CONT; 1785 ALU_END_TO_BE: 1786 switch (IMM) { 1787 case 16: 1788 DST = (__force u16) cpu_to_be16(DST); 1789 break; 1790 case 32: 1791 DST = (__force u32) cpu_to_be32(DST); 1792 break; 1793 case 64: 1794 DST = (__force u64) cpu_to_be64(DST); 1795 break; 1796 } 1797 CONT; 1798 ALU_END_TO_LE: 1799 switch (IMM) { 1800 case 16: 1801 DST = (__force u16) cpu_to_le16(DST); 1802 break; 1803 case 32: 1804 DST = (__force u32) cpu_to_le32(DST); 1805 break; 1806 case 64: 1807 DST = (__force u64) cpu_to_le64(DST); 1808 break; 1809 } 1810 CONT; 1811 1812 /* CALL */ 1813 JMP_CALL: 1814 /* Function call scratches BPF_R1-BPF_R5 registers, 1815 * preserves BPF_R6-BPF_R9, and stores return value 1816 * into BPF_R0. 1817 */ 1818 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1819 BPF_R4, BPF_R5); 1820 CONT; 1821 1822 JMP_CALL_ARGS: 1823 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1824 BPF_R3, BPF_R4, 1825 BPF_R5, 1826 insn + insn->off + 1); 1827 CONT; 1828 1829 JMP_TAIL_CALL: { 1830 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1831 struct bpf_array *array = container_of(map, struct bpf_array, map); 1832 struct bpf_prog *prog; 1833 u32 index = BPF_R3; 1834 1835 if (unlikely(index >= array->map.max_entries)) 1836 goto out; 1837 1838 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 1839 goto out; 1840 1841 tail_call_cnt++; 1842 1843 prog = READ_ONCE(array->ptrs[index]); 1844 if (!prog) 1845 goto out; 1846 1847 /* ARG1 at this point is guaranteed to point to CTX from 1848 * the verifier side due to the fact that the tail call is 1849 * handled like a helper, that is, bpf_tail_call_proto, 1850 * where arg1_type is ARG_PTR_TO_CTX. 1851 */ 1852 insn = prog->insnsi; 1853 goto select_insn; 1854 out: 1855 CONT; 1856 } 1857 JMP_JA: 1858 insn += insn->off; 1859 CONT; 1860 JMP_EXIT: 1861 return BPF_R0; 1862 /* JMP */ 1863 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1864 JMP_##OPCODE##_X: \ 1865 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1866 insn += insn->off; \ 1867 CONT_JMP; \ 1868 } \ 1869 CONT; \ 1870 JMP32_##OPCODE##_X: \ 1871 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1872 insn += insn->off; \ 1873 CONT_JMP; \ 1874 } \ 1875 CONT; \ 1876 JMP_##OPCODE##_K: \ 1877 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1878 insn += insn->off; \ 1879 CONT_JMP; \ 1880 } \ 1881 CONT; \ 1882 JMP32_##OPCODE##_K: \ 1883 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1884 insn += insn->off; \ 1885 CONT_JMP; \ 1886 } \ 1887 CONT; 1888 COND_JMP(u, JEQ, ==) 1889 COND_JMP(u, JNE, !=) 1890 COND_JMP(u, JGT, >) 1891 COND_JMP(u, JLT, <) 1892 COND_JMP(u, JGE, >=) 1893 COND_JMP(u, JLE, <=) 1894 COND_JMP(u, JSET, &) 1895 COND_JMP(s, JSGT, >) 1896 COND_JMP(s, JSLT, <) 1897 COND_JMP(s, JSGE, >=) 1898 COND_JMP(s, JSLE, <=) 1899 #undef COND_JMP 1900 /* ST, STX and LDX*/ 1901 ST_NOSPEC: 1902 /* Speculation barrier for mitigating Speculative Store Bypass. 1903 * In case of arm64, we rely on the firmware mitigation as 1904 * controlled via the ssbd kernel parameter. Whenever the 1905 * mitigation is enabled, it works for all of the kernel code 1906 * with no need to provide any additional instructions here. 1907 * In case of x86, we use 'lfence' insn for mitigation. We 1908 * reuse preexisting logic from Spectre v1 mitigation that 1909 * happens to produce the required code on x86 for v4 as well. 1910 */ 1911 #ifdef CONFIG_X86 1912 barrier_nospec(); 1913 #endif 1914 CONT; 1915 #define LDST(SIZEOP, SIZE) \ 1916 STX_MEM_##SIZEOP: \ 1917 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1918 CONT; \ 1919 ST_MEM_##SIZEOP: \ 1920 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1921 CONT; \ 1922 LDX_MEM_##SIZEOP: \ 1923 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1924 CONT; \ 1925 LDX_PROBE_MEM_##SIZEOP: \ 1926 bpf_probe_read_kernel(&DST, sizeof(SIZE), \ 1927 (const void *)(long) (SRC + insn->off)); \ 1928 DST = *((SIZE *)&DST); \ 1929 CONT; 1930 1931 LDST(B, u8) 1932 LDST(H, u16) 1933 LDST(W, u32) 1934 LDST(DW, u64) 1935 #undef LDST 1936 1937 #define ATOMIC_ALU_OP(BOP, KOP) \ 1938 case BOP: \ 1939 if (BPF_SIZE(insn->code) == BPF_W) \ 1940 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 1941 (DST + insn->off)); \ 1942 else \ 1943 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 1944 (DST + insn->off)); \ 1945 break; \ 1946 case BOP | BPF_FETCH: \ 1947 if (BPF_SIZE(insn->code) == BPF_W) \ 1948 SRC = (u32) atomic_fetch_##KOP( \ 1949 (u32) SRC, \ 1950 (atomic_t *)(unsigned long) (DST + insn->off)); \ 1951 else \ 1952 SRC = (u64) atomic64_fetch_##KOP( \ 1953 (u64) SRC, \ 1954 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 1955 break; 1956 1957 STX_ATOMIC_DW: 1958 STX_ATOMIC_W: 1959 switch (IMM) { 1960 ATOMIC_ALU_OP(BPF_ADD, add) 1961 ATOMIC_ALU_OP(BPF_AND, and) 1962 ATOMIC_ALU_OP(BPF_OR, or) 1963 ATOMIC_ALU_OP(BPF_XOR, xor) 1964 #undef ATOMIC_ALU_OP 1965 1966 case BPF_XCHG: 1967 if (BPF_SIZE(insn->code) == BPF_W) 1968 SRC = (u32) atomic_xchg( 1969 (atomic_t *)(unsigned long) (DST + insn->off), 1970 (u32) SRC); 1971 else 1972 SRC = (u64) atomic64_xchg( 1973 (atomic64_t *)(unsigned long) (DST + insn->off), 1974 (u64) SRC); 1975 break; 1976 case BPF_CMPXCHG: 1977 if (BPF_SIZE(insn->code) == BPF_W) 1978 BPF_R0 = (u32) atomic_cmpxchg( 1979 (atomic_t *)(unsigned long) (DST + insn->off), 1980 (u32) BPF_R0, (u32) SRC); 1981 else 1982 BPF_R0 = (u64) atomic64_cmpxchg( 1983 (atomic64_t *)(unsigned long) (DST + insn->off), 1984 (u64) BPF_R0, (u64) SRC); 1985 break; 1986 1987 default: 1988 goto default_label; 1989 } 1990 CONT; 1991 1992 default_label: 1993 /* If we ever reach this, we have a bug somewhere. Die hard here 1994 * instead of just returning 0; we could be somewhere in a subprog, 1995 * so execution could continue otherwise which we do /not/ want. 1996 * 1997 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 1998 */ 1999 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2000 insn->code, insn->imm); 2001 BUG_ON(1); 2002 return 0; 2003 } 2004 2005 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2006 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2007 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2008 { \ 2009 u64 stack[stack_size / sizeof(u64)]; \ 2010 u64 regs[MAX_BPF_EXT_REG] = {}; \ 2011 \ 2012 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2013 ARG1 = (u64) (unsigned long) ctx; \ 2014 return ___bpf_prog_run(regs, insn); \ 2015 } 2016 2017 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2018 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2019 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2020 const struct bpf_insn *insn) \ 2021 { \ 2022 u64 stack[stack_size / sizeof(u64)]; \ 2023 u64 regs[MAX_BPF_EXT_REG]; \ 2024 \ 2025 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2026 BPF_R1 = r1; \ 2027 BPF_R2 = r2; \ 2028 BPF_R3 = r3; \ 2029 BPF_R4 = r4; \ 2030 BPF_R5 = r5; \ 2031 return ___bpf_prog_run(regs, insn); \ 2032 } 2033 2034 #define EVAL1(FN, X) FN(X) 2035 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2036 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2037 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2038 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2039 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2040 2041 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2042 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2043 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2044 2045 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2046 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2047 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2048 2049 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2050 2051 static unsigned int (*interpreters[])(const void *ctx, 2052 const struct bpf_insn *insn) = { 2053 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2054 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2055 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2056 }; 2057 #undef PROG_NAME_LIST 2058 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2059 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2060 const struct bpf_insn *insn) = { 2061 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2062 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2063 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2064 }; 2065 #undef PROG_NAME_LIST 2066 2067 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2068 { 2069 stack_depth = max_t(u32, stack_depth, 1); 2070 insn->off = (s16) insn->imm; 2071 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2072 __bpf_call_base_args; 2073 insn->code = BPF_JMP | BPF_CALL_ARGS; 2074 } 2075 2076 #else 2077 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2078 const struct bpf_insn *insn) 2079 { 2080 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2081 * is not working properly, so warn about it! 2082 */ 2083 WARN_ON_ONCE(1); 2084 return 0; 2085 } 2086 #endif 2087 2088 bool bpf_prog_map_compatible(struct bpf_map *map, 2089 const struct bpf_prog *fp) 2090 { 2091 bool ret; 2092 2093 if (fp->kprobe_override) 2094 return false; 2095 2096 spin_lock(&map->owner.lock); 2097 if (!map->owner.type) { 2098 /* There's no owner yet where we could check for 2099 * compatibility. 2100 */ 2101 map->owner.type = fp->type; 2102 map->owner.jited = fp->jited; 2103 map->owner.xdp_has_frags = fp->aux->xdp_has_frags; 2104 ret = true; 2105 } else { 2106 ret = map->owner.type == fp->type && 2107 map->owner.jited == fp->jited && 2108 map->owner.xdp_has_frags == fp->aux->xdp_has_frags; 2109 } 2110 spin_unlock(&map->owner.lock); 2111 2112 return ret; 2113 } 2114 2115 static int bpf_check_tail_call(const struct bpf_prog *fp) 2116 { 2117 struct bpf_prog_aux *aux = fp->aux; 2118 int i, ret = 0; 2119 2120 mutex_lock(&aux->used_maps_mutex); 2121 for (i = 0; i < aux->used_map_cnt; i++) { 2122 struct bpf_map *map = aux->used_maps[i]; 2123 2124 if (!map_type_contains_progs(map)) 2125 continue; 2126 2127 if (!bpf_prog_map_compatible(map, fp)) { 2128 ret = -EINVAL; 2129 goto out; 2130 } 2131 } 2132 2133 out: 2134 mutex_unlock(&aux->used_maps_mutex); 2135 return ret; 2136 } 2137 2138 static void bpf_prog_select_func(struct bpf_prog *fp) 2139 { 2140 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2141 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2142 2143 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 2144 #else 2145 fp->bpf_func = __bpf_prog_ret0_warn; 2146 #endif 2147 } 2148 2149 /** 2150 * bpf_prog_select_runtime - select exec runtime for BPF program 2151 * @fp: bpf_prog populated with BPF program 2152 * @err: pointer to error variable 2153 * 2154 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2155 * The BPF program will be executed via bpf_prog_run() function. 2156 * 2157 * Return: the &fp argument along with &err set to 0 for success or 2158 * a negative errno code on failure 2159 */ 2160 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2161 { 2162 /* In case of BPF to BPF calls, verifier did all the prep 2163 * work with regards to JITing, etc. 2164 */ 2165 bool jit_needed = false; 2166 2167 if (fp->bpf_func) 2168 goto finalize; 2169 2170 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2171 bpf_prog_has_kfunc_call(fp)) 2172 jit_needed = true; 2173 2174 bpf_prog_select_func(fp); 2175 2176 /* eBPF JITs can rewrite the program in case constant 2177 * blinding is active. However, in case of error during 2178 * blinding, bpf_int_jit_compile() must always return a 2179 * valid program, which in this case would simply not 2180 * be JITed, but falls back to the interpreter. 2181 */ 2182 if (!bpf_prog_is_dev_bound(fp->aux)) { 2183 *err = bpf_prog_alloc_jited_linfo(fp); 2184 if (*err) 2185 return fp; 2186 2187 fp = bpf_int_jit_compile(fp); 2188 bpf_prog_jit_attempt_done(fp); 2189 if (!fp->jited && jit_needed) { 2190 *err = -ENOTSUPP; 2191 return fp; 2192 } 2193 } else { 2194 *err = bpf_prog_offload_compile(fp); 2195 if (*err) 2196 return fp; 2197 } 2198 2199 finalize: 2200 bpf_prog_lock_ro(fp); 2201 2202 /* The tail call compatibility check can only be done at 2203 * this late stage as we need to determine, if we deal 2204 * with JITed or non JITed program concatenations and not 2205 * all eBPF JITs might immediately support all features. 2206 */ 2207 *err = bpf_check_tail_call(fp); 2208 2209 return fp; 2210 } 2211 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2212 2213 static unsigned int __bpf_prog_ret1(const void *ctx, 2214 const struct bpf_insn *insn) 2215 { 2216 return 1; 2217 } 2218 2219 static struct bpf_prog_dummy { 2220 struct bpf_prog prog; 2221 } dummy_bpf_prog = { 2222 .prog = { 2223 .bpf_func = __bpf_prog_ret1, 2224 }, 2225 }; 2226 2227 struct bpf_empty_prog_array bpf_empty_prog_array = { 2228 .null_prog = NULL, 2229 }; 2230 EXPORT_SYMBOL(bpf_empty_prog_array); 2231 2232 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2233 { 2234 if (prog_cnt) 2235 return kzalloc(sizeof(struct bpf_prog_array) + 2236 sizeof(struct bpf_prog_array_item) * 2237 (prog_cnt + 1), 2238 flags); 2239 2240 return &bpf_empty_prog_array.hdr; 2241 } 2242 2243 void bpf_prog_array_free(struct bpf_prog_array *progs) 2244 { 2245 if (!progs || progs == &bpf_empty_prog_array.hdr) 2246 return; 2247 kfree_rcu(progs, rcu); 2248 } 2249 2250 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2251 { 2252 struct bpf_prog_array *progs; 2253 2254 progs = container_of(rcu, struct bpf_prog_array, rcu); 2255 kfree_rcu(progs, rcu); 2256 } 2257 2258 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2259 { 2260 if (!progs || progs == &bpf_empty_prog_array.hdr) 2261 return; 2262 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2263 } 2264 2265 int bpf_prog_array_length(struct bpf_prog_array *array) 2266 { 2267 struct bpf_prog_array_item *item; 2268 u32 cnt = 0; 2269 2270 for (item = array->items; item->prog; item++) 2271 if (item->prog != &dummy_bpf_prog.prog) 2272 cnt++; 2273 return cnt; 2274 } 2275 2276 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2277 { 2278 struct bpf_prog_array_item *item; 2279 2280 for (item = array->items; item->prog; item++) 2281 if (item->prog != &dummy_bpf_prog.prog) 2282 return false; 2283 return true; 2284 } 2285 2286 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2287 u32 *prog_ids, 2288 u32 request_cnt) 2289 { 2290 struct bpf_prog_array_item *item; 2291 int i = 0; 2292 2293 for (item = array->items; item->prog; item++) { 2294 if (item->prog == &dummy_bpf_prog.prog) 2295 continue; 2296 prog_ids[i] = item->prog->aux->id; 2297 if (++i == request_cnt) { 2298 item++; 2299 break; 2300 } 2301 } 2302 2303 return !!(item->prog); 2304 } 2305 2306 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2307 __u32 __user *prog_ids, u32 cnt) 2308 { 2309 unsigned long err = 0; 2310 bool nospc; 2311 u32 *ids; 2312 2313 /* users of this function are doing: 2314 * cnt = bpf_prog_array_length(); 2315 * if (cnt > 0) 2316 * bpf_prog_array_copy_to_user(..., cnt); 2317 * so below kcalloc doesn't need extra cnt > 0 check. 2318 */ 2319 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2320 if (!ids) 2321 return -ENOMEM; 2322 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2323 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2324 kfree(ids); 2325 if (err) 2326 return -EFAULT; 2327 if (nospc) 2328 return -ENOSPC; 2329 return 0; 2330 } 2331 2332 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2333 struct bpf_prog *old_prog) 2334 { 2335 struct bpf_prog_array_item *item; 2336 2337 for (item = array->items; item->prog; item++) 2338 if (item->prog == old_prog) { 2339 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2340 break; 2341 } 2342 } 2343 2344 /** 2345 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2346 * index into the program array with 2347 * a dummy no-op program. 2348 * @array: a bpf_prog_array 2349 * @index: the index of the program to replace 2350 * 2351 * Skips over dummy programs, by not counting them, when calculating 2352 * the position of the program to replace. 2353 * 2354 * Return: 2355 * * 0 - Success 2356 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2357 * * -ENOENT - Index out of range 2358 */ 2359 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2360 { 2361 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2362 } 2363 2364 /** 2365 * bpf_prog_array_update_at() - Updates the program at the given index 2366 * into the program array. 2367 * @array: a bpf_prog_array 2368 * @index: the index of the program to update 2369 * @prog: the program to insert into the array 2370 * 2371 * Skips over dummy programs, by not counting them, when calculating 2372 * the position of the program to update. 2373 * 2374 * Return: 2375 * * 0 - Success 2376 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2377 * * -ENOENT - Index out of range 2378 */ 2379 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2380 struct bpf_prog *prog) 2381 { 2382 struct bpf_prog_array_item *item; 2383 2384 if (unlikely(index < 0)) 2385 return -EINVAL; 2386 2387 for (item = array->items; item->prog; item++) { 2388 if (item->prog == &dummy_bpf_prog.prog) 2389 continue; 2390 if (!index) { 2391 WRITE_ONCE(item->prog, prog); 2392 return 0; 2393 } 2394 index--; 2395 } 2396 return -ENOENT; 2397 } 2398 2399 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2400 struct bpf_prog *exclude_prog, 2401 struct bpf_prog *include_prog, 2402 u64 bpf_cookie, 2403 struct bpf_prog_array **new_array) 2404 { 2405 int new_prog_cnt, carry_prog_cnt = 0; 2406 struct bpf_prog_array_item *existing, *new; 2407 struct bpf_prog_array *array; 2408 bool found_exclude = false; 2409 2410 /* Figure out how many existing progs we need to carry over to 2411 * the new array. 2412 */ 2413 if (old_array) { 2414 existing = old_array->items; 2415 for (; existing->prog; existing++) { 2416 if (existing->prog == exclude_prog) { 2417 found_exclude = true; 2418 continue; 2419 } 2420 if (existing->prog != &dummy_bpf_prog.prog) 2421 carry_prog_cnt++; 2422 if (existing->prog == include_prog) 2423 return -EEXIST; 2424 } 2425 } 2426 2427 if (exclude_prog && !found_exclude) 2428 return -ENOENT; 2429 2430 /* How many progs (not NULL) will be in the new array? */ 2431 new_prog_cnt = carry_prog_cnt; 2432 if (include_prog) 2433 new_prog_cnt += 1; 2434 2435 /* Do we have any prog (not NULL) in the new array? */ 2436 if (!new_prog_cnt) { 2437 *new_array = NULL; 2438 return 0; 2439 } 2440 2441 /* +1 as the end of prog_array is marked with NULL */ 2442 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2443 if (!array) 2444 return -ENOMEM; 2445 new = array->items; 2446 2447 /* Fill in the new prog array */ 2448 if (carry_prog_cnt) { 2449 existing = old_array->items; 2450 for (; existing->prog; existing++) { 2451 if (existing->prog == exclude_prog || 2452 existing->prog == &dummy_bpf_prog.prog) 2453 continue; 2454 2455 new->prog = existing->prog; 2456 new->bpf_cookie = existing->bpf_cookie; 2457 new++; 2458 } 2459 } 2460 if (include_prog) { 2461 new->prog = include_prog; 2462 new->bpf_cookie = bpf_cookie; 2463 new++; 2464 } 2465 new->prog = NULL; 2466 *new_array = array; 2467 return 0; 2468 } 2469 2470 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2471 u32 *prog_ids, u32 request_cnt, 2472 u32 *prog_cnt) 2473 { 2474 u32 cnt = 0; 2475 2476 if (array) 2477 cnt = bpf_prog_array_length(array); 2478 2479 *prog_cnt = cnt; 2480 2481 /* return early if user requested only program count or nothing to copy */ 2482 if (!request_cnt || !cnt) 2483 return 0; 2484 2485 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2486 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2487 : 0; 2488 } 2489 2490 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2491 struct bpf_map **used_maps, u32 len) 2492 { 2493 struct bpf_map *map; 2494 u32 i; 2495 2496 for (i = 0; i < len; i++) { 2497 map = used_maps[i]; 2498 if (map->ops->map_poke_untrack) 2499 map->ops->map_poke_untrack(map, aux); 2500 bpf_map_put(map); 2501 } 2502 } 2503 2504 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2505 { 2506 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2507 kfree(aux->used_maps); 2508 } 2509 2510 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2511 struct btf_mod_pair *used_btfs, u32 len) 2512 { 2513 #ifdef CONFIG_BPF_SYSCALL 2514 struct btf_mod_pair *btf_mod; 2515 u32 i; 2516 2517 for (i = 0; i < len; i++) { 2518 btf_mod = &used_btfs[i]; 2519 if (btf_mod->module) 2520 module_put(btf_mod->module); 2521 btf_put(btf_mod->btf); 2522 } 2523 #endif 2524 } 2525 2526 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2527 { 2528 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2529 kfree(aux->used_btfs); 2530 } 2531 2532 static void bpf_prog_free_deferred(struct work_struct *work) 2533 { 2534 struct bpf_prog_aux *aux; 2535 int i; 2536 2537 aux = container_of(work, struct bpf_prog_aux, work); 2538 #ifdef CONFIG_BPF_SYSCALL 2539 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2540 #endif 2541 #ifdef CONFIG_CGROUP_BPF 2542 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2543 bpf_cgroup_atype_put(aux->cgroup_atype); 2544 #endif 2545 bpf_free_used_maps(aux); 2546 bpf_free_used_btfs(aux); 2547 if (bpf_prog_is_dev_bound(aux)) 2548 bpf_prog_offload_destroy(aux->prog); 2549 #ifdef CONFIG_PERF_EVENTS 2550 if (aux->prog->has_callchain_buf) 2551 put_callchain_buffers(); 2552 #endif 2553 if (aux->dst_trampoline) 2554 bpf_trampoline_put(aux->dst_trampoline); 2555 for (i = 0; i < aux->func_cnt; i++) { 2556 /* We can just unlink the subprog poke descriptor table as 2557 * it was originally linked to the main program and is also 2558 * released along with it. 2559 */ 2560 aux->func[i]->aux->poke_tab = NULL; 2561 bpf_jit_free(aux->func[i]); 2562 } 2563 if (aux->func_cnt) { 2564 kfree(aux->func); 2565 bpf_prog_unlock_free(aux->prog); 2566 } else { 2567 bpf_jit_free(aux->prog); 2568 } 2569 } 2570 2571 void bpf_prog_free(struct bpf_prog *fp) 2572 { 2573 struct bpf_prog_aux *aux = fp->aux; 2574 2575 if (aux->dst_prog) 2576 bpf_prog_put(aux->dst_prog); 2577 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2578 schedule_work(&aux->work); 2579 } 2580 EXPORT_SYMBOL_GPL(bpf_prog_free); 2581 2582 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2583 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2584 2585 void bpf_user_rnd_init_once(void) 2586 { 2587 prandom_init_once(&bpf_user_rnd_state); 2588 } 2589 2590 BPF_CALL_0(bpf_user_rnd_u32) 2591 { 2592 /* Should someone ever have the rather unwise idea to use some 2593 * of the registers passed into this function, then note that 2594 * this function is called from native eBPF and classic-to-eBPF 2595 * transformations. Register assignments from both sides are 2596 * different, f.e. classic always sets fn(ctx, A, X) here. 2597 */ 2598 struct rnd_state *state; 2599 u32 res; 2600 2601 state = &get_cpu_var(bpf_user_rnd_state); 2602 res = prandom_u32_state(state); 2603 put_cpu_var(bpf_user_rnd_state); 2604 2605 return res; 2606 } 2607 2608 BPF_CALL_0(bpf_get_raw_cpu_id) 2609 { 2610 return raw_smp_processor_id(); 2611 } 2612 2613 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2614 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2615 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2616 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2617 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2618 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2619 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2620 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2621 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2622 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2623 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2624 2625 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2626 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2627 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2628 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2629 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2630 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2631 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak; 2632 2633 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2634 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2635 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2636 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2637 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2638 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2639 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2640 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2641 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2642 const struct bpf_func_proto bpf_set_retval_proto __weak; 2643 const struct bpf_func_proto bpf_get_retval_proto __weak; 2644 2645 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2646 { 2647 return NULL; 2648 } 2649 2650 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2651 { 2652 return NULL; 2653 } 2654 2655 u64 __weak 2656 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2657 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2658 { 2659 return -ENOTSUPP; 2660 } 2661 EXPORT_SYMBOL_GPL(bpf_event_output); 2662 2663 /* Always built-in helper functions. */ 2664 const struct bpf_func_proto bpf_tail_call_proto = { 2665 .func = NULL, 2666 .gpl_only = false, 2667 .ret_type = RET_VOID, 2668 .arg1_type = ARG_PTR_TO_CTX, 2669 .arg2_type = ARG_CONST_MAP_PTR, 2670 .arg3_type = ARG_ANYTHING, 2671 }; 2672 2673 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2674 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2675 * eBPF and implicitly also cBPF can get JITed! 2676 */ 2677 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2678 { 2679 return prog; 2680 } 2681 2682 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2683 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2684 */ 2685 void __weak bpf_jit_compile(struct bpf_prog *prog) 2686 { 2687 } 2688 2689 bool __weak bpf_helper_changes_pkt_data(void *func) 2690 { 2691 return false; 2692 } 2693 2694 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2695 * analysis code and wants explicit zero extension inserted by verifier. 2696 * Otherwise, return FALSE. 2697 * 2698 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2699 * you don't override this. JITs that don't want these extra insns can detect 2700 * them using insn_is_zext. 2701 */ 2702 bool __weak bpf_jit_needs_zext(void) 2703 { 2704 return false; 2705 } 2706 2707 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 2708 bool __weak bpf_jit_supports_subprog_tailcalls(void) 2709 { 2710 return false; 2711 } 2712 2713 bool __weak bpf_jit_supports_kfunc_call(void) 2714 { 2715 return false; 2716 } 2717 2718 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2719 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2720 */ 2721 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2722 int len) 2723 { 2724 return -EFAULT; 2725 } 2726 2727 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2728 void *addr1, void *addr2) 2729 { 2730 return -ENOTSUPP; 2731 } 2732 2733 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 2734 { 2735 return ERR_PTR(-ENOTSUPP); 2736 } 2737 2738 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 2739 { 2740 return -ENOTSUPP; 2741 } 2742 2743 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2744 EXPORT_SYMBOL(bpf_stats_enabled_key); 2745 2746 /* All definitions of tracepoints related to BPF. */ 2747 #define CREATE_TRACE_POINTS 2748 #include <linux/bpf_trace.h> 2749 2750 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2751 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2752