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 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 829 830 static DEFINE_MUTEX(pack_mutex); 831 static LIST_HEAD(pack_list); 832 833 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 834 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 835 */ 836 #ifdef PMD_SIZE 837 #define BPF_PROG_PACK_SIZE (PMD_SIZE * num_possible_nodes()) 838 #else 839 #define BPF_PROG_PACK_SIZE PAGE_SIZE 840 #endif 841 842 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 843 844 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 845 { 846 struct bpf_prog_pack *pack; 847 848 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), 849 GFP_KERNEL); 850 if (!pack) 851 return NULL; 852 pack->ptr = module_alloc(BPF_PROG_PACK_SIZE); 853 if (!pack->ptr) { 854 kfree(pack); 855 return NULL; 856 } 857 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 858 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 859 list_add_tail(&pack->list, &pack_list); 860 861 set_vm_flush_reset_perms(pack->ptr); 862 set_memory_ro((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 863 set_memory_x((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 864 return pack; 865 } 866 867 static void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 868 { 869 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 870 struct bpf_prog_pack *pack; 871 unsigned long pos; 872 void *ptr = NULL; 873 874 mutex_lock(&pack_mutex); 875 if (size > BPF_PROG_PACK_SIZE) { 876 size = round_up(size, PAGE_SIZE); 877 ptr = module_alloc(size); 878 if (ptr) { 879 bpf_fill_ill_insns(ptr, size); 880 set_vm_flush_reset_perms(ptr); 881 set_memory_ro((unsigned long)ptr, size / PAGE_SIZE); 882 set_memory_x((unsigned long)ptr, size / PAGE_SIZE); 883 } 884 goto out; 885 } 886 list_for_each_entry(pack, &pack_list, list) { 887 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 888 nbits, 0); 889 if (pos < BPF_PROG_CHUNK_COUNT) 890 goto found_free_area; 891 } 892 893 pack = alloc_new_pack(bpf_fill_ill_insns); 894 if (!pack) 895 goto out; 896 897 pos = 0; 898 899 found_free_area: 900 bitmap_set(pack->bitmap, pos, nbits); 901 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 902 903 out: 904 mutex_unlock(&pack_mutex); 905 return ptr; 906 } 907 908 static void bpf_prog_pack_free(struct bpf_binary_header *hdr) 909 { 910 struct bpf_prog_pack *pack = NULL, *tmp; 911 unsigned int nbits; 912 unsigned long pos; 913 914 mutex_lock(&pack_mutex); 915 if (hdr->size > BPF_PROG_PACK_SIZE) { 916 module_memfree(hdr); 917 goto out; 918 } 919 920 list_for_each_entry(tmp, &pack_list, list) { 921 if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) { 922 pack = tmp; 923 break; 924 } 925 } 926 927 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 928 goto out; 929 930 nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size); 931 pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; 932 933 WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size), 934 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 935 936 bitmap_clear(pack->bitmap, pos, nbits); 937 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 938 BPF_PROG_CHUNK_COUNT, 0) == 0) { 939 list_del(&pack->list); 940 module_memfree(pack->ptr); 941 kfree(pack); 942 } 943 out: 944 mutex_unlock(&pack_mutex); 945 } 946 947 static atomic_long_t bpf_jit_current; 948 949 /* Can be overridden by an arch's JIT compiler if it has a custom, 950 * dedicated BPF backend memory area, or if neither of the two 951 * below apply. 952 */ 953 u64 __weak bpf_jit_alloc_exec_limit(void) 954 { 955 #if defined(MODULES_VADDR) 956 return MODULES_END - MODULES_VADDR; 957 #else 958 return VMALLOC_END - VMALLOC_START; 959 #endif 960 } 961 962 static int __init bpf_jit_charge_init(void) 963 { 964 /* Only used as heuristic here to derive limit. */ 965 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 966 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2, 967 PAGE_SIZE), LONG_MAX); 968 return 0; 969 } 970 pure_initcall(bpf_jit_charge_init); 971 972 int bpf_jit_charge_modmem(u32 size) 973 { 974 if (atomic_long_add_return(size, &bpf_jit_current) > bpf_jit_limit) { 975 if (!bpf_capable()) { 976 atomic_long_sub(size, &bpf_jit_current); 977 return -EPERM; 978 } 979 } 980 981 return 0; 982 } 983 984 void bpf_jit_uncharge_modmem(u32 size) 985 { 986 atomic_long_sub(size, &bpf_jit_current); 987 } 988 989 void *__weak bpf_jit_alloc_exec(unsigned long size) 990 { 991 return module_alloc(size); 992 } 993 994 void __weak bpf_jit_free_exec(void *addr) 995 { 996 module_memfree(addr); 997 } 998 999 struct bpf_binary_header * 1000 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1001 unsigned int alignment, 1002 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1003 { 1004 struct bpf_binary_header *hdr; 1005 u32 size, hole, start; 1006 1007 WARN_ON_ONCE(!is_power_of_2(alignment) || 1008 alignment > BPF_IMAGE_ALIGNMENT); 1009 1010 /* Most of BPF filters are really small, but if some of them 1011 * fill a page, allow at least 128 extra bytes to insert a 1012 * random section of illegal instructions. 1013 */ 1014 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1015 1016 if (bpf_jit_charge_modmem(size)) 1017 return NULL; 1018 hdr = bpf_jit_alloc_exec(size); 1019 if (!hdr) { 1020 bpf_jit_uncharge_modmem(size); 1021 return NULL; 1022 } 1023 1024 /* Fill space with illegal/arch-dep instructions. */ 1025 bpf_fill_ill_insns(hdr, size); 1026 1027 hdr->size = size; 1028 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1029 PAGE_SIZE - sizeof(*hdr)); 1030 start = (get_random_int() % hole) & ~(alignment - 1); 1031 1032 /* Leave a random number of instructions before BPF code. */ 1033 *image_ptr = &hdr->image[start]; 1034 1035 return hdr; 1036 } 1037 1038 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1039 { 1040 u32 size = hdr->size; 1041 1042 bpf_jit_free_exec(hdr); 1043 bpf_jit_uncharge_modmem(size); 1044 } 1045 1046 /* Allocate jit binary from bpf_prog_pack allocator. 1047 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1048 * to the memory. To solve this problem, a RW buffer is also allocated at 1049 * as the same time. The JIT engine should calculate offsets based on the 1050 * RO memory address, but write JITed program to the RW buffer. Once the 1051 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1052 * the JITed program to the RO memory. 1053 */ 1054 struct bpf_binary_header * 1055 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1056 unsigned int alignment, 1057 struct bpf_binary_header **rw_header, 1058 u8 **rw_image, 1059 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1060 { 1061 struct bpf_binary_header *ro_header; 1062 u32 size, hole, start; 1063 1064 WARN_ON_ONCE(!is_power_of_2(alignment) || 1065 alignment > BPF_IMAGE_ALIGNMENT); 1066 1067 /* add 16 bytes for a random section of illegal instructions */ 1068 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1069 1070 if (bpf_jit_charge_modmem(size)) 1071 return NULL; 1072 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1073 if (!ro_header) { 1074 bpf_jit_uncharge_modmem(size); 1075 return NULL; 1076 } 1077 1078 *rw_header = kvmalloc(size, GFP_KERNEL); 1079 if (!*rw_header) { 1080 bpf_arch_text_copy(&ro_header->size, &size, sizeof(size)); 1081 bpf_prog_pack_free(ro_header); 1082 bpf_jit_uncharge_modmem(size); 1083 return NULL; 1084 } 1085 1086 /* Fill space with illegal/arch-dep instructions. */ 1087 bpf_fill_ill_insns(*rw_header, size); 1088 (*rw_header)->size = size; 1089 1090 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1091 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1092 start = (get_random_int() % hole) & ~(alignment - 1); 1093 1094 *image_ptr = &ro_header->image[start]; 1095 *rw_image = &(*rw_header)->image[start]; 1096 1097 return ro_header; 1098 } 1099 1100 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1101 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, 1102 struct bpf_binary_header *ro_header, 1103 struct bpf_binary_header *rw_header) 1104 { 1105 void *ptr; 1106 1107 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1108 1109 kvfree(rw_header); 1110 1111 if (IS_ERR(ptr)) { 1112 bpf_prog_pack_free(ro_header); 1113 return PTR_ERR(ptr); 1114 } 1115 return 0; 1116 } 1117 1118 /* bpf_jit_binary_pack_free is called in two different scenarios: 1119 * 1) when the program is freed after; 1120 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1121 * For case 2), we need to free both the RO memory and the RW buffer. 1122 * 1123 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1124 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1125 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1126 * bpf_arch_text_copy (when jit fails). 1127 */ 1128 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1129 struct bpf_binary_header *rw_header) 1130 { 1131 u32 size = ro_header->size; 1132 1133 bpf_prog_pack_free(ro_header); 1134 kvfree(rw_header); 1135 bpf_jit_uncharge_modmem(size); 1136 } 1137 1138 struct bpf_binary_header * 1139 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp) 1140 { 1141 unsigned long real_start = (unsigned long)fp->bpf_func; 1142 unsigned long addr; 1143 1144 addr = real_start & BPF_PROG_CHUNK_MASK; 1145 return (void *)addr; 1146 } 1147 1148 static inline struct bpf_binary_header * 1149 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1150 { 1151 unsigned long real_start = (unsigned long)fp->bpf_func; 1152 unsigned long addr; 1153 1154 addr = real_start & PAGE_MASK; 1155 return (void *)addr; 1156 } 1157 1158 /* This symbol is only overridden by archs that have different 1159 * requirements than the usual eBPF JITs, f.e. when they only 1160 * implement cBPF JIT, do not set images read-only, etc. 1161 */ 1162 void __weak bpf_jit_free(struct bpf_prog *fp) 1163 { 1164 if (fp->jited) { 1165 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1166 1167 bpf_jit_binary_free(hdr); 1168 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1169 } 1170 1171 bpf_prog_unlock_free(fp); 1172 } 1173 1174 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1175 const struct bpf_insn *insn, bool extra_pass, 1176 u64 *func_addr, bool *func_addr_fixed) 1177 { 1178 s16 off = insn->off; 1179 s32 imm = insn->imm; 1180 u8 *addr; 1181 1182 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1183 if (!*func_addr_fixed) { 1184 /* Place-holder address till the last pass has collected 1185 * all addresses for JITed subprograms in which case we 1186 * can pick them up from prog->aux. 1187 */ 1188 if (!extra_pass) 1189 addr = NULL; 1190 else if (prog->aux->func && 1191 off >= 0 && off < prog->aux->func_cnt) 1192 addr = (u8 *)prog->aux->func[off]->bpf_func; 1193 else 1194 return -EINVAL; 1195 } else { 1196 /* Address of a BPF helper call. Since part of the core 1197 * kernel, it's always at a fixed location. __bpf_call_base 1198 * and the helper with imm relative to it are both in core 1199 * kernel. 1200 */ 1201 addr = (u8 *)__bpf_call_base + imm; 1202 } 1203 1204 *func_addr = (unsigned long)addr; 1205 return 0; 1206 } 1207 1208 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1209 const struct bpf_insn *aux, 1210 struct bpf_insn *to_buff, 1211 bool emit_zext) 1212 { 1213 struct bpf_insn *to = to_buff; 1214 u32 imm_rnd = get_random_int(); 1215 s16 off; 1216 1217 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1218 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1219 1220 /* Constraints on AX register: 1221 * 1222 * AX register is inaccessible from user space. It is mapped in 1223 * all JITs, and used here for constant blinding rewrites. It is 1224 * typically "stateless" meaning its contents are only valid within 1225 * the executed instruction, but not across several instructions. 1226 * There are a few exceptions however which are further detailed 1227 * below. 1228 * 1229 * Constant blinding is only used by JITs, not in the interpreter. 1230 * The interpreter uses AX in some occasions as a local temporary 1231 * register e.g. in DIV or MOD instructions. 1232 * 1233 * In restricted circumstances, the verifier can also use the AX 1234 * register for rewrites as long as they do not interfere with 1235 * the above cases! 1236 */ 1237 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1238 goto out; 1239 1240 if (from->imm == 0 && 1241 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1242 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1243 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1244 goto out; 1245 } 1246 1247 switch (from->code) { 1248 case BPF_ALU | BPF_ADD | BPF_K: 1249 case BPF_ALU | BPF_SUB | BPF_K: 1250 case BPF_ALU | BPF_AND | BPF_K: 1251 case BPF_ALU | BPF_OR | BPF_K: 1252 case BPF_ALU | BPF_XOR | BPF_K: 1253 case BPF_ALU | BPF_MUL | BPF_K: 1254 case BPF_ALU | BPF_MOV | BPF_K: 1255 case BPF_ALU | BPF_DIV | BPF_K: 1256 case BPF_ALU | BPF_MOD | BPF_K: 1257 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1258 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1259 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1260 break; 1261 1262 case BPF_ALU64 | BPF_ADD | BPF_K: 1263 case BPF_ALU64 | BPF_SUB | BPF_K: 1264 case BPF_ALU64 | BPF_AND | BPF_K: 1265 case BPF_ALU64 | BPF_OR | BPF_K: 1266 case BPF_ALU64 | BPF_XOR | BPF_K: 1267 case BPF_ALU64 | BPF_MUL | BPF_K: 1268 case BPF_ALU64 | BPF_MOV | BPF_K: 1269 case BPF_ALU64 | BPF_DIV | BPF_K: 1270 case BPF_ALU64 | BPF_MOD | BPF_K: 1271 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1272 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1273 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1274 break; 1275 1276 case BPF_JMP | BPF_JEQ | BPF_K: 1277 case BPF_JMP | BPF_JNE | BPF_K: 1278 case BPF_JMP | BPF_JGT | BPF_K: 1279 case BPF_JMP | BPF_JLT | BPF_K: 1280 case BPF_JMP | BPF_JGE | BPF_K: 1281 case BPF_JMP | BPF_JLE | BPF_K: 1282 case BPF_JMP | BPF_JSGT | BPF_K: 1283 case BPF_JMP | BPF_JSLT | BPF_K: 1284 case BPF_JMP | BPF_JSGE | BPF_K: 1285 case BPF_JMP | BPF_JSLE | BPF_K: 1286 case BPF_JMP | BPF_JSET | BPF_K: 1287 /* Accommodate for extra offset in case of a backjump. */ 1288 off = from->off; 1289 if (off < 0) 1290 off -= 2; 1291 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1292 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1293 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1294 break; 1295 1296 case BPF_JMP32 | BPF_JEQ | BPF_K: 1297 case BPF_JMP32 | BPF_JNE | BPF_K: 1298 case BPF_JMP32 | BPF_JGT | BPF_K: 1299 case BPF_JMP32 | BPF_JLT | BPF_K: 1300 case BPF_JMP32 | BPF_JGE | BPF_K: 1301 case BPF_JMP32 | BPF_JLE | BPF_K: 1302 case BPF_JMP32 | BPF_JSGT | BPF_K: 1303 case BPF_JMP32 | BPF_JSLT | BPF_K: 1304 case BPF_JMP32 | BPF_JSGE | BPF_K: 1305 case BPF_JMP32 | BPF_JSLE | BPF_K: 1306 case BPF_JMP32 | BPF_JSET | BPF_K: 1307 /* Accommodate for extra offset in case of a backjump. */ 1308 off = from->off; 1309 if (off < 0) 1310 off -= 2; 1311 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1312 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1313 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1314 off); 1315 break; 1316 1317 case BPF_LD | BPF_IMM | BPF_DW: 1318 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1319 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1320 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1321 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1322 break; 1323 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1324 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1325 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1326 if (emit_zext) 1327 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1328 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1329 break; 1330 1331 case BPF_ST | BPF_MEM | BPF_DW: 1332 case BPF_ST | BPF_MEM | BPF_W: 1333 case BPF_ST | BPF_MEM | BPF_H: 1334 case BPF_ST | BPF_MEM | BPF_B: 1335 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1336 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1337 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1338 break; 1339 } 1340 out: 1341 return to - to_buff; 1342 } 1343 1344 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1345 gfp_t gfp_extra_flags) 1346 { 1347 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1348 struct bpf_prog *fp; 1349 1350 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1351 if (fp != NULL) { 1352 /* aux->prog still points to the fp_other one, so 1353 * when promoting the clone to the real program, 1354 * this still needs to be adapted. 1355 */ 1356 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1357 } 1358 1359 return fp; 1360 } 1361 1362 static void bpf_prog_clone_free(struct bpf_prog *fp) 1363 { 1364 /* aux was stolen by the other clone, so we cannot free 1365 * it from this path! It will be freed eventually by the 1366 * other program on release. 1367 * 1368 * At this point, we don't need a deferred release since 1369 * clone is guaranteed to not be locked. 1370 */ 1371 fp->aux = NULL; 1372 fp->stats = NULL; 1373 fp->active = NULL; 1374 __bpf_prog_free(fp); 1375 } 1376 1377 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1378 { 1379 /* We have to repoint aux->prog to self, as we don't 1380 * know whether fp here is the clone or the original. 1381 */ 1382 fp->aux->prog = fp; 1383 bpf_prog_clone_free(fp_other); 1384 } 1385 1386 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1387 { 1388 struct bpf_insn insn_buff[16], aux[2]; 1389 struct bpf_prog *clone, *tmp; 1390 int insn_delta, insn_cnt; 1391 struct bpf_insn *insn; 1392 int i, rewritten; 1393 1394 if (!prog->blinding_requested || prog->blinded) 1395 return prog; 1396 1397 clone = bpf_prog_clone_create(prog, GFP_USER); 1398 if (!clone) 1399 return ERR_PTR(-ENOMEM); 1400 1401 insn_cnt = clone->len; 1402 insn = clone->insnsi; 1403 1404 for (i = 0; i < insn_cnt; i++, insn++) { 1405 if (bpf_pseudo_func(insn)) { 1406 /* ld_imm64 with an address of bpf subprog is not 1407 * a user controlled constant. Don't randomize it, 1408 * since it will conflict with jit_subprogs() logic. 1409 */ 1410 insn++; 1411 i++; 1412 continue; 1413 } 1414 1415 /* We temporarily need to hold the original ld64 insn 1416 * so that we can still access the first part in the 1417 * second blinding run. 1418 */ 1419 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1420 insn[1].code == 0) 1421 memcpy(aux, insn, sizeof(aux)); 1422 1423 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1424 clone->aux->verifier_zext); 1425 if (!rewritten) 1426 continue; 1427 1428 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1429 if (IS_ERR(tmp)) { 1430 /* Patching may have repointed aux->prog during 1431 * realloc from the original one, so we need to 1432 * fix it up here on error. 1433 */ 1434 bpf_jit_prog_release_other(prog, clone); 1435 return tmp; 1436 } 1437 1438 clone = tmp; 1439 insn_delta = rewritten - 1; 1440 1441 /* Walk new program and skip insns we just inserted. */ 1442 insn = clone->insnsi + i + insn_delta; 1443 insn_cnt += insn_delta; 1444 i += insn_delta; 1445 } 1446 1447 clone->blinded = 1; 1448 return clone; 1449 } 1450 #endif /* CONFIG_BPF_JIT */ 1451 1452 /* Base function for offset calculation. Needs to go into .text section, 1453 * therefore keeping it non-static as well; will also be used by JITs 1454 * anyway later on, so do not let the compiler omit it. This also needs 1455 * to go into kallsyms for correlation from e.g. bpftool, so naming 1456 * must not change. 1457 */ 1458 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1459 { 1460 return 0; 1461 } 1462 EXPORT_SYMBOL_GPL(__bpf_call_base); 1463 1464 /* All UAPI available opcodes. */ 1465 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1466 /* 32 bit ALU operations. */ \ 1467 /* Register based. */ \ 1468 INSN_3(ALU, ADD, X), \ 1469 INSN_3(ALU, SUB, X), \ 1470 INSN_3(ALU, AND, X), \ 1471 INSN_3(ALU, OR, X), \ 1472 INSN_3(ALU, LSH, X), \ 1473 INSN_3(ALU, RSH, X), \ 1474 INSN_3(ALU, XOR, X), \ 1475 INSN_3(ALU, MUL, X), \ 1476 INSN_3(ALU, MOV, X), \ 1477 INSN_3(ALU, ARSH, X), \ 1478 INSN_3(ALU, DIV, X), \ 1479 INSN_3(ALU, MOD, X), \ 1480 INSN_2(ALU, NEG), \ 1481 INSN_3(ALU, END, TO_BE), \ 1482 INSN_3(ALU, END, TO_LE), \ 1483 /* Immediate based. */ \ 1484 INSN_3(ALU, ADD, K), \ 1485 INSN_3(ALU, SUB, K), \ 1486 INSN_3(ALU, AND, K), \ 1487 INSN_3(ALU, OR, K), \ 1488 INSN_3(ALU, LSH, K), \ 1489 INSN_3(ALU, RSH, K), \ 1490 INSN_3(ALU, XOR, K), \ 1491 INSN_3(ALU, MUL, K), \ 1492 INSN_3(ALU, MOV, K), \ 1493 INSN_3(ALU, ARSH, K), \ 1494 INSN_3(ALU, DIV, K), \ 1495 INSN_3(ALU, MOD, K), \ 1496 /* 64 bit ALU operations. */ \ 1497 /* Register based. */ \ 1498 INSN_3(ALU64, ADD, X), \ 1499 INSN_3(ALU64, SUB, X), \ 1500 INSN_3(ALU64, AND, X), \ 1501 INSN_3(ALU64, OR, X), \ 1502 INSN_3(ALU64, LSH, X), \ 1503 INSN_3(ALU64, RSH, X), \ 1504 INSN_3(ALU64, XOR, X), \ 1505 INSN_3(ALU64, MUL, X), \ 1506 INSN_3(ALU64, MOV, X), \ 1507 INSN_3(ALU64, ARSH, X), \ 1508 INSN_3(ALU64, DIV, X), \ 1509 INSN_3(ALU64, MOD, X), \ 1510 INSN_2(ALU64, NEG), \ 1511 /* Immediate based. */ \ 1512 INSN_3(ALU64, ADD, K), \ 1513 INSN_3(ALU64, SUB, K), \ 1514 INSN_3(ALU64, AND, K), \ 1515 INSN_3(ALU64, OR, K), \ 1516 INSN_3(ALU64, LSH, K), \ 1517 INSN_3(ALU64, RSH, K), \ 1518 INSN_3(ALU64, XOR, K), \ 1519 INSN_3(ALU64, MUL, K), \ 1520 INSN_3(ALU64, MOV, K), \ 1521 INSN_3(ALU64, ARSH, K), \ 1522 INSN_3(ALU64, DIV, K), \ 1523 INSN_3(ALU64, MOD, K), \ 1524 /* Call instruction. */ \ 1525 INSN_2(JMP, CALL), \ 1526 /* Exit instruction. */ \ 1527 INSN_2(JMP, EXIT), \ 1528 /* 32-bit Jump instructions. */ \ 1529 /* Register based. */ \ 1530 INSN_3(JMP32, JEQ, X), \ 1531 INSN_3(JMP32, JNE, X), \ 1532 INSN_3(JMP32, JGT, X), \ 1533 INSN_3(JMP32, JLT, X), \ 1534 INSN_3(JMP32, JGE, X), \ 1535 INSN_3(JMP32, JLE, X), \ 1536 INSN_3(JMP32, JSGT, X), \ 1537 INSN_3(JMP32, JSLT, X), \ 1538 INSN_3(JMP32, JSGE, X), \ 1539 INSN_3(JMP32, JSLE, X), \ 1540 INSN_3(JMP32, JSET, X), \ 1541 /* Immediate based. */ \ 1542 INSN_3(JMP32, JEQ, K), \ 1543 INSN_3(JMP32, JNE, K), \ 1544 INSN_3(JMP32, JGT, K), \ 1545 INSN_3(JMP32, JLT, K), \ 1546 INSN_3(JMP32, JGE, K), \ 1547 INSN_3(JMP32, JLE, K), \ 1548 INSN_3(JMP32, JSGT, K), \ 1549 INSN_3(JMP32, JSLT, K), \ 1550 INSN_3(JMP32, JSGE, K), \ 1551 INSN_3(JMP32, JSLE, K), \ 1552 INSN_3(JMP32, JSET, K), \ 1553 /* Jump instructions. */ \ 1554 /* Register based. */ \ 1555 INSN_3(JMP, JEQ, X), \ 1556 INSN_3(JMP, JNE, X), \ 1557 INSN_3(JMP, JGT, X), \ 1558 INSN_3(JMP, JLT, X), \ 1559 INSN_3(JMP, JGE, X), \ 1560 INSN_3(JMP, JLE, X), \ 1561 INSN_3(JMP, JSGT, X), \ 1562 INSN_3(JMP, JSLT, X), \ 1563 INSN_3(JMP, JSGE, X), \ 1564 INSN_3(JMP, JSLE, X), \ 1565 INSN_3(JMP, JSET, X), \ 1566 /* Immediate based. */ \ 1567 INSN_3(JMP, JEQ, K), \ 1568 INSN_3(JMP, JNE, K), \ 1569 INSN_3(JMP, JGT, K), \ 1570 INSN_3(JMP, JLT, K), \ 1571 INSN_3(JMP, JGE, K), \ 1572 INSN_3(JMP, JLE, K), \ 1573 INSN_3(JMP, JSGT, K), \ 1574 INSN_3(JMP, JSLT, K), \ 1575 INSN_3(JMP, JSGE, K), \ 1576 INSN_3(JMP, JSLE, K), \ 1577 INSN_3(JMP, JSET, K), \ 1578 INSN_2(JMP, JA), \ 1579 /* Store instructions. */ \ 1580 /* Register based. */ \ 1581 INSN_3(STX, MEM, B), \ 1582 INSN_3(STX, MEM, H), \ 1583 INSN_3(STX, MEM, W), \ 1584 INSN_3(STX, MEM, DW), \ 1585 INSN_3(STX, ATOMIC, W), \ 1586 INSN_3(STX, ATOMIC, DW), \ 1587 /* Immediate based. */ \ 1588 INSN_3(ST, MEM, B), \ 1589 INSN_3(ST, MEM, H), \ 1590 INSN_3(ST, MEM, W), \ 1591 INSN_3(ST, MEM, DW), \ 1592 /* Load instructions. */ \ 1593 /* Register based. */ \ 1594 INSN_3(LDX, MEM, B), \ 1595 INSN_3(LDX, MEM, H), \ 1596 INSN_3(LDX, MEM, W), \ 1597 INSN_3(LDX, MEM, DW), \ 1598 /* Immediate based. */ \ 1599 INSN_3(LD, IMM, DW) 1600 1601 bool bpf_opcode_in_insntable(u8 code) 1602 { 1603 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1604 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1605 static const bool public_insntable[256] = { 1606 [0 ... 255] = false, 1607 /* Now overwrite non-defaults ... */ 1608 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1609 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1610 [BPF_LD | BPF_ABS | BPF_B] = true, 1611 [BPF_LD | BPF_ABS | BPF_H] = true, 1612 [BPF_LD | BPF_ABS | BPF_W] = true, 1613 [BPF_LD | BPF_IND | BPF_B] = true, 1614 [BPF_LD | BPF_IND | BPF_H] = true, 1615 [BPF_LD | BPF_IND | BPF_W] = true, 1616 }; 1617 #undef BPF_INSN_3_TBL 1618 #undef BPF_INSN_2_TBL 1619 return public_insntable[code]; 1620 } 1621 1622 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1623 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1624 { 1625 memset(dst, 0, size); 1626 return -EFAULT; 1627 } 1628 1629 /** 1630 * ___bpf_prog_run - run eBPF program on a given context 1631 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1632 * @insn: is the array of eBPF instructions 1633 * 1634 * Decode and execute eBPF instructions. 1635 * 1636 * Return: whatever value is in %BPF_R0 at program exit 1637 */ 1638 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1639 { 1640 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1641 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1642 static const void * const jumptable[256] __annotate_jump_table = { 1643 [0 ... 255] = &&default_label, 1644 /* Now overwrite non-defaults ... */ 1645 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1646 /* Non-UAPI available opcodes. */ 1647 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1648 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1649 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1650 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1651 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1652 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1653 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1654 }; 1655 #undef BPF_INSN_3_LBL 1656 #undef BPF_INSN_2_LBL 1657 u32 tail_call_cnt = 0; 1658 1659 #define CONT ({ insn++; goto select_insn; }) 1660 #define CONT_JMP ({ insn++; goto select_insn; }) 1661 1662 select_insn: 1663 goto *jumptable[insn->code]; 1664 1665 /* Explicitly mask the register-based shift amounts with 63 or 31 1666 * to avoid undefined behavior. Normally this won't affect the 1667 * generated code, for example, in case of native 64 bit archs such 1668 * as x86-64 or arm64, the compiler is optimizing the AND away for 1669 * the interpreter. In case of JITs, each of the JIT backends compiles 1670 * the BPF shift operations to machine instructions which produce 1671 * implementation-defined results in such a case; the resulting 1672 * contents of the register may be arbitrary, but program behaviour 1673 * as a whole remains defined. In other words, in case of JIT backends, 1674 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1675 */ 1676 /* ALU (shifts) */ 1677 #define SHT(OPCODE, OP) \ 1678 ALU64_##OPCODE##_X: \ 1679 DST = DST OP (SRC & 63); \ 1680 CONT; \ 1681 ALU_##OPCODE##_X: \ 1682 DST = (u32) DST OP ((u32) SRC & 31); \ 1683 CONT; \ 1684 ALU64_##OPCODE##_K: \ 1685 DST = DST OP IMM; \ 1686 CONT; \ 1687 ALU_##OPCODE##_K: \ 1688 DST = (u32) DST OP (u32) IMM; \ 1689 CONT; 1690 /* ALU (rest) */ 1691 #define ALU(OPCODE, OP) \ 1692 ALU64_##OPCODE##_X: \ 1693 DST = DST OP SRC; \ 1694 CONT; \ 1695 ALU_##OPCODE##_X: \ 1696 DST = (u32) DST OP (u32) SRC; \ 1697 CONT; \ 1698 ALU64_##OPCODE##_K: \ 1699 DST = DST OP IMM; \ 1700 CONT; \ 1701 ALU_##OPCODE##_K: \ 1702 DST = (u32) DST OP (u32) IMM; \ 1703 CONT; 1704 ALU(ADD, +) 1705 ALU(SUB, -) 1706 ALU(AND, &) 1707 ALU(OR, |) 1708 ALU(XOR, ^) 1709 ALU(MUL, *) 1710 SHT(LSH, <<) 1711 SHT(RSH, >>) 1712 #undef SHT 1713 #undef ALU 1714 ALU_NEG: 1715 DST = (u32) -DST; 1716 CONT; 1717 ALU64_NEG: 1718 DST = -DST; 1719 CONT; 1720 ALU_MOV_X: 1721 DST = (u32) SRC; 1722 CONT; 1723 ALU_MOV_K: 1724 DST = (u32) IMM; 1725 CONT; 1726 ALU64_MOV_X: 1727 DST = SRC; 1728 CONT; 1729 ALU64_MOV_K: 1730 DST = IMM; 1731 CONT; 1732 LD_IMM_DW: 1733 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1734 insn++; 1735 CONT; 1736 ALU_ARSH_X: 1737 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1738 CONT; 1739 ALU_ARSH_K: 1740 DST = (u64) (u32) (((s32) DST) >> IMM); 1741 CONT; 1742 ALU64_ARSH_X: 1743 (*(s64 *) &DST) >>= (SRC & 63); 1744 CONT; 1745 ALU64_ARSH_K: 1746 (*(s64 *) &DST) >>= IMM; 1747 CONT; 1748 ALU64_MOD_X: 1749 div64_u64_rem(DST, SRC, &AX); 1750 DST = AX; 1751 CONT; 1752 ALU_MOD_X: 1753 AX = (u32) DST; 1754 DST = do_div(AX, (u32) SRC); 1755 CONT; 1756 ALU64_MOD_K: 1757 div64_u64_rem(DST, IMM, &AX); 1758 DST = AX; 1759 CONT; 1760 ALU_MOD_K: 1761 AX = (u32) DST; 1762 DST = do_div(AX, (u32) IMM); 1763 CONT; 1764 ALU64_DIV_X: 1765 DST = div64_u64(DST, SRC); 1766 CONT; 1767 ALU_DIV_X: 1768 AX = (u32) DST; 1769 do_div(AX, (u32) SRC); 1770 DST = (u32) AX; 1771 CONT; 1772 ALU64_DIV_K: 1773 DST = div64_u64(DST, IMM); 1774 CONT; 1775 ALU_DIV_K: 1776 AX = (u32) DST; 1777 do_div(AX, (u32) IMM); 1778 DST = (u32) AX; 1779 CONT; 1780 ALU_END_TO_BE: 1781 switch (IMM) { 1782 case 16: 1783 DST = (__force u16) cpu_to_be16(DST); 1784 break; 1785 case 32: 1786 DST = (__force u32) cpu_to_be32(DST); 1787 break; 1788 case 64: 1789 DST = (__force u64) cpu_to_be64(DST); 1790 break; 1791 } 1792 CONT; 1793 ALU_END_TO_LE: 1794 switch (IMM) { 1795 case 16: 1796 DST = (__force u16) cpu_to_le16(DST); 1797 break; 1798 case 32: 1799 DST = (__force u32) cpu_to_le32(DST); 1800 break; 1801 case 64: 1802 DST = (__force u64) cpu_to_le64(DST); 1803 break; 1804 } 1805 CONT; 1806 1807 /* CALL */ 1808 JMP_CALL: 1809 /* Function call scratches BPF_R1-BPF_R5 registers, 1810 * preserves BPF_R6-BPF_R9, and stores return value 1811 * into BPF_R0. 1812 */ 1813 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1814 BPF_R4, BPF_R5); 1815 CONT; 1816 1817 JMP_CALL_ARGS: 1818 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1819 BPF_R3, BPF_R4, 1820 BPF_R5, 1821 insn + insn->off + 1); 1822 CONT; 1823 1824 JMP_TAIL_CALL: { 1825 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1826 struct bpf_array *array = container_of(map, struct bpf_array, map); 1827 struct bpf_prog *prog; 1828 u32 index = BPF_R3; 1829 1830 if (unlikely(index >= array->map.max_entries)) 1831 goto out; 1832 1833 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 1834 goto out; 1835 1836 tail_call_cnt++; 1837 1838 prog = READ_ONCE(array->ptrs[index]); 1839 if (!prog) 1840 goto out; 1841 1842 /* ARG1 at this point is guaranteed to point to CTX from 1843 * the verifier side due to the fact that the tail call is 1844 * handled like a helper, that is, bpf_tail_call_proto, 1845 * where arg1_type is ARG_PTR_TO_CTX. 1846 */ 1847 insn = prog->insnsi; 1848 goto select_insn; 1849 out: 1850 CONT; 1851 } 1852 JMP_JA: 1853 insn += insn->off; 1854 CONT; 1855 JMP_EXIT: 1856 return BPF_R0; 1857 /* JMP */ 1858 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1859 JMP_##OPCODE##_X: \ 1860 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1861 insn += insn->off; \ 1862 CONT_JMP; \ 1863 } \ 1864 CONT; \ 1865 JMP32_##OPCODE##_X: \ 1866 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1867 insn += insn->off; \ 1868 CONT_JMP; \ 1869 } \ 1870 CONT; \ 1871 JMP_##OPCODE##_K: \ 1872 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1873 insn += insn->off; \ 1874 CONT_JMP; \ 1875 } \ 1876 CONT; \ 1877 JMP32_##OPCODE##_K: \ 1878 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1879 insn += insn->off; \ 1880 CONT_JMP; \ 1881 } \ 1882 CONT; 1883 COND_JMP(u, JEQ, ==) 1884 COND_JMP(u, JNE, !=) 1885 COND_JMP(u, JGT, >) 1886 COND_JMP(u, JLT, <) 1887 COND_JMP(u, JGE, >=) 1888 COND_JMP(u, JLE, <=) 1889 COND_JMP(u, JSET, &) 1890 COND_JMP(s, JSGT, >) 1891 COND_JMP(s, JSLT, <) 1892 COND_JMP(s, JSGE, >=) 1893 COND_JMP(s, JSLE, <=) 1894 #undef COND_JMP 1895 /* ST, STX and LDX*/ 1896 ST_NOSPEC: 1897 /* Speculation barrier for mitigating Speculative Store Bypass. 1898 * In case of arm64, we rely on the firmware mitigation as 1899 * controlled via the ssbd kernel parameter. Whenever the 1900 * mitigation is enabled, it works for all of the kernel code 1901 * with no need to provide any additional instructions here. 1902 * In case of x86, we use 'lfence' insn for mitigation. We 1903 * reuse preexisting logic from Spectre v1 mitigation that 1904 * happens to produce the required code on x86 for v4 as well. 1905 */ 1906 #ifdef CONFIG_X86 1907 barrier_nospec(); 1908 #endif 1909 CONT; 1910 #define LDST(SIZEOP, SIZE) \ 1911 STX_MEM_##SIZEOP: \ 1912 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1913 CONT; \ 1914 ST_MEM_##SIZEOP: \ 1915 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1916 CONT; \ 1917 LDX_MEM_##SIZEOP: \ 1918 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1919 CONT; \ 1920 LDX_PROBE_MEM_##SIZEOP: \ 1921 bpf_probe_read_kernel(&DST, sizeof(SIZE), \ 1922 (const void *)(long) (SRC + insn->off)); \ 1923 DST = *((SIZE *)&DST); \ 1924 CONT; 1925 1926 LDST(B, u8) 1927 LDST(H, u16) 1928 LDST(W, u32) 1929 LDST(DW, u64) 1930 #undef LDST 1931 1932 #define ATOMIC_ALU_OP(BOP, KOP) \ 1933 case BOP: \ 1934 if (BPF_SIZE(insn->code) == BPF_W) \ 1935 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 1936 (DST + insn->off)); \ 1937 else \ 1938 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 1939 (DST + insn->off)); \ 1940 break; \ 1941 case BOP | BPF_FETCH: \ 1942 if (BPF_SIZE(insn->code) == BPF_W) \ 1943 SRC = (u32) atomic_fetch_##KOP( \ 1944 (u32) SRC, \ 1945 (atomic_t *)(unsigned long) (DST + insn->off)); \ 1946 else \ 1947 SRC = (u64) atomic64_fetch_##KOP( \ 1948 (u64) SRC, \ 1949 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 1950 break; 1951 1952 STX_ATOMIC_DW: 1953 STX_ATOMIC_W: 1954 switch (IMM) { 1955 ATOMIC_ALU_OP(BPF_ADD, add) 1956 ATOMIC_ALU_OP(BPF_AND, and) 1957 ATOMIC_ALU_OP(BPF_OR, or) 1958 ATOMIC_ALU_OP(BPF_XOR, xor) 1959 #undef ATOMIC_ALU_OP 1960 1961 case BPF_XCHG: 1962 if (BPF_SIZE(insn->code) == BPF_W) 1963 SRC = (u32) atomic_xchg( 1964 (atomic_t *)(unsigned long) (DST + insn->off), 1965 (u32) SRC); 1966 else 1967 SRC = (u64) atomic64_xchg( 1968 (atomic64_t *)(unsigned long) (DST + insn->off), 1969 (u64) SRC); 1970 break; 1971 case BPF_CMPXCHG: 1972 if (BPF_SIZE(insn->code) == BPF_W) 1973 BPF_R0 = (u32) atomic_cmpxchg( 1974 (atomic_t *)(unsigned long) (DST + insn->off), 1975 (u32) BPF_R0, (u32) SRC); 1976 else 1977 BPF_R0 = (u64) atomic64_cmpxchg( 1978 (atomic64_t *)(unsigned long) (DST + insn->off), 1979 (u64) BPF_R0, (u64) SRC); 1980 break; 1981 1982 default: 1983 goto default_label; 1984 } 1985 CONT; 1986 1987 default_label: 1988 /* If we ever reach this, we have a bug somewhere. Die hard here 1989 * instead of just returning 0; we could be somewhere in a subprog, 1990 * so execution could continue otherwise which we do /not/ want. 1991 * 1992 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 1993 */ 1994 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 1995 insn->code, insn->imm); 1996 BUG_ON(1); 1997 return 0; 1998 } 1999 2000 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2001 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2002 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2003 { \ 2004 u64 stack[stack_size / sizeof(u64)]; \ 2005 u64 regs[MAX_BPF_EXT_REG]; \ 2006 \ 2007 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2008 ARG1 = (u64) (unsigned long) ctx; \ 2009 return ___bpf_prog_run(regs, insn); \ 2010 } 2011 2012 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2013 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2014 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2015 const struct bpf_insn *insn) \ 2016 { \ 2017 u64 stack[stack_size / sizeof(u64)]; \ 2018 u64 regs[MAX_BPF_EXT_REG]; \ 2019 \ 2020 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2021 BPF_R1 = r1; \ 2022 BPF_R2 = r2; \ 2023 BPF_R3 = r3; \ 2024 BPF_R4 = r4; \ 2025 BPF_R5 = r5; \ 2026 return ___bpf_prog_run(regs, insn); \ 2027 } 2028 2029 #define EVAL1(FN, X) FN(X) 2030 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2031 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2032 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2033 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2034 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2035 2036 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2037 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2038 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2039 2040 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2041 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2042 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2043 2044 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2045 2046 static unsigned int (*interpreters[])(const void *ctx, 2047 const struct bpf_insn *insn) = { 2048 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2049 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2050 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2051 }; 2052 #undef PROG_NAME_LIST 2053 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2054 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2055 const struct bpf_insn *insn) = { 2056 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2057 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2058 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2059 }; 2060 #undef PROG_NAME_LIST 2061 2062 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2063 { 2064 stack_depth = max_t(u32, stack_depth, 1); 2065 insn->off = (s16) insn->imm; 2066 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2067 __bpf_call_base_args; 2068 insn->code = BPF_JMP | BPF_CALL_ARGS; 2069 } 2070 2071 #else 2072 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2073 const struct bpf_insn *insn) 2074 { 2075 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2076 * is not working properly, so warn about it! 2077 */ 2078 WARN_ON_ONCE(1); 2079 return 0; 2080 } 2081 #endif 2082 2083 bool bpf_prog_map_compatible(struct bpf_map *map, 2084 const struct bpf_prog *fp) 2085 { 2086 bool ret; 2087 2088 if (fp->kprobe_override) 2089 return false; 2090 2091 spin_lock(&map->owner.lock); 2092 if (!map->owner.type) { 2093 /* There's no owner yet where we could check for 2094 * compatibility. 2095 */ 2096 map->owner.type = fp->type; 2097 map->owner.jited = fp->jited; 2098 map->owner.xdp_has_frags = fp->aux->xdp_has_frags; 2099 ret = true; 2100 } else { 2101 ret = map->owner.type == fp->type && 2102 map->owner.jited == fp->jited && 2103 map->owner.xdp_has_frags == fp->aux->xdp_has_frags; 2104 } 2105 spin_unlock(&map->owner.lock); 2106 2107 return ret; 2108 } 2109 2110 static int bpf_check_tail_call(const struct bpf_prog *fp) 2111 { 2112 struct bpf_prog_aux *aux = fp->aux; 2113 int i, ret = 0; 2114 2115 mutex_lock(&aux->used_maps_mutex); 2116 for (i = 0; i < aux->used_map_cnt; i++) { 2117 struct bpf_map *map = aux->used_maps[i]; 2118 2119 if (!map_type_contains_progs(map)) 2120 continue; 2121 2122 if (!bpf_prog_map_compatible(map, fp)) { 2123 ret = -EINVAL; 2124 goto out; 2125 } 2126 } 2127 2128 out: 2129 mutex_unlock(&aux->used_maps_mutex); 2130 return ret; 2131 } 2132 2133 static void bpf_prog_select_func(struct bpf_prog *fp) 2134 { 2135 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2136 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2137 2138 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 2139 #else 2140 fp->bpf_func = __bpf_prog_ret0_warn; 2141 #endif 2142 } 2143 2144 /** 2145 * bpf_prog_select_runtime - select exec runtime for BPF program 2146 * @fp: bpf_prog populated with BPF program 2147 * @err: pointer to error variable 2148 * 2149 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2150 * The BPF program will be executed via bpf_prog_run() function. 2151 * 2152 * Return: the &fp argument along with &err set to 0 for success or 2153 * a negative errno code on failure 2154 */ 2155 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2156 { 2157 /* In case of BPF to BPF calls, verifier did all the prep 2158 * work with regards to JITing, etc. 2159 */ 2160 bool jit_needed = false; 2161 2162 if (fp->bpf_func) 2163 goto finalize; 2164 2165 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2166 bpf_prog_has_kfunc_call(fp)) 2167 jit_needed = true; 2168 2169 bpf_prog_select_func(fp); 2170 2171 /* eBPF JITs can rewrite the program in case constant 2172 * blinding is active. However, in case of error during 2173 * blinding, bpf_int_jit_compile() must always return a 2174 * valid program, which in this case would simply not 2175 * be JITed, but falls back to the interpreter. 2176 */ 2177 if (!bpf_prog_is_dev_bound(fp->aux)) { 2178 *err = bpf_prog_alloc_jited_linfo(fp); 2179 if (*err) 2180 return fp; 2181 2182 fp = bpf_int_jit_compile(fp); 2183 bpf_prog_jit_attempt_done(fp); 2184 if (!fp->jited && jit_needed) { 2185 *err = -ENOTSUPP; 2186 return fp; 2187 } 2188 } else { 2189 *err = bpf_prog_offload_compile(fp); 2190 if (*err) 2191 return fp; 2192 } 2193 2194 finalize: 2195 bpf_prog_lock_ro(fp); 2196 2197 /* The tail call compatibility check can only be done at 2198 * this late stage as we need to determine, if we deal 2199 * with JITed or non JITed program concatenations and not 2200 * all eBPF JITs might immediately support all features. 2201 */ 2202 *err = bpf_check_tail_call(fp); 2203 2204 return fp; 2205 } 2206 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2207 2208 static unsigned int __bpf_prog_ret1(const void *ctx, 2209 const struct bpf_insn *insn) 2210 { 2211 return 1; 2212 } 2213 2214 static struct bpf_prog_dummy { 2215 struct bpf_prog prog; 2216 } dummy_bpf_prog = { 2217 .prog = { 2218 .bpf_func = __bpf_prog_ret1, 2219 }, 2220 }; 2221 2222 struct bpf_empty_prog_array bpf_empty_prog_array = { 2223 .null_prog = NULL, 2224 }; 2225 EXPORT_SYMBOL(bpf_empty_prog_array); 2226 2227 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2228 { 2229 if (prog_cnt) 2230 return kzalloc(sizeof(struct bpf_prog_array) + 2231 sizeof(struct bpf_prog_array_item) * 2232 (prog_cnt + 1), 2233 flags); 2234 2235 return &bpf_empty_prog_array.hdr; 2236 } 2237 2238 void bpf_prog_array_free(struct bpf_prog_array *progs) 2239 { 2240 if (!progs || progs == &bpf_empty_prog_array.hdr) 2241 return; 2242 kfree_rcu(progs, rcu); 2243 } 2244 2245 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2246 { 2247 struct bpf_prog_array *progs; 2248 2249 progs = container_of(rcu, struct bpf_prog_array, rcu); 2250 kfree_rcu(progs, rcu); 2251 } 2252 2253 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2254 { 2255 if (!progs || progs == &bpf_empty_prog_array.hdr) 2256 return; 2257 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2258 } 2259 2260 int bpf_prog_array_length(struct bpf_prog_array *array) 2261 { 2262 struct bpf_prog_array_item *item; 2263 u32 cnt = 0; 2264 2265 for (item = array->items; item->prog; item++) 2266 if (item->prog != &dummy_bpf_prog.prog) 2267 cnt++; 2268 return cnt; 2269 } 2270 2271 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2272 { 2273 struct bpf_prog_array_item *item; 2274 2275 for (item = array->items; item->prog; item++) 2276 if (item->prog != &dummy_bpf_prog.prog) 2277 return false; 2278 return true; 2279 } 2280 2281 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2282 u32 *prog_ids, 2283 u32 request_cnt) 2284 { 2285 struct bpf_prog_array_item *item; 2286 int i = 0; 2287 2288 for (item = array->items; item->prog; item++) { 2289 if (item->prog == &dummy_bpf_prog.prog) 2290 continue; 2291 prog_ids[i] = item->prog->aux->id; 2292 if (++i == request_cnt) { 2293 item++; 2294 break; 2295 } 2296 } 2297 2298 return !!(item->prog); 2299 } 2300 2301 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2302 __u32 __user *prog_ids, u32 cnt) 2303 { 2304 unsigned long err = 0; 2305 bool nospc; 2306 u32 *ids; 2307 2308 /* users of this function are doing: 2309 * cnt = bpf_prog_array_length(); 2310 * if (cnt > 0) 2311 * bpf_prog_array_copy_to_user(..., cnt); 2312 * so below kcalloc doesn't need extra cnt > 0 check. 2313 */ 2314 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2315 if (!ids) 2316 return -ENOMEM; 2317 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2318 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2319 kfree(ids); 2320 if (err) 2321 return -EFAULT; 2322 if (nospc) 2323 return -ENOSPC; 2324 return 0; 2325 } 2326 2327 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2328 struct bpf_prog *old_prog) 2329 { 2330 struct bpf_prog_array_item *item; 2331 2332 for (item = array->items; item->prog; item++) 2333 if (item->prog == old_prog) { 2334 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2335 break; 2336 } 2337 } 2338 2339 /** 2340 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2341 * index into the program array with 2342 * a dummy no-op program. 2343 * @array: a bpf_prog_array 2344 * @index: the index of the program to replace 2345 * 2346 * Skips over dummy programs, by not counting them, when calculating 2347 * the position of the program to replace. 2348 * 2349 * Return: 2350 * * 0 - Success 2351 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2352 * * -ENOENT - Index out of range 2353 */ 2354 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2355 { 2356 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2357 } 2358 2359 /** 2360 * bpf_prog_array_update_at() - Updates the program at the given index 2361 * into the program array. 2362 * @array: a bpf_prog_array 2363 * @index: the index of the program to update 2364 * @prog: the program to insert into the array 2365 * 2366 * Skips over dummy programs, by not counting them, when calculating 2367 * the position of the program to update. 2368 * 2369 * Return: 2370 * * 0 - Success 2371 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2372 * * -ENOENT - Index out of range 2373 */ 2374 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2375 struct bpf_prog *prog) 2376 { 2377 struct bpf_prog_array_item *item; 2378 2379 if (unlikely(index < 0)) 2380 return -EINVAL; 2381 2382 for (item = array->items; item->prog; item++) { 2383 if (item->prog == &dummy_bpf_prog.prog) 2384 continue; 2385 if (!index) { 2386 WRITE_ONCE(item->prog, prog); 2387 return 0; 2388 } 2389 index--; 2390 } 2391 return -ENOENT; 2392 } 2393 2394 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2395 struct bpf_prog *exclude_prog, 2396 struct bpf_prog *include_prog, 2397 u64 bpf_cookie, 2398 struct bpf_prog_array **new_array) 2399 { 2400 int new_prog_cnt, carry_prog_cnt = 0; 2401 struct bpf_prog_array_item *existing, *new; 2402 struct bpf_prog_array *array; 2403 bool found_exclude = false; 2404 2405 /* Figure out how many existing progs we need to carry over to 2406 * the new array. 2407 */ 2408 if (old_array) { 2409 existing = old_array->items; 2410 for (; existing->prog; existing++) { 2411 if (existing->prog == exclude_prog) { 2412 found_exclude = true; 2413 continue; 2414 } 2415 if (existing->prog != &dummy_bpf_prog.prog) 2416 carry_prog_cnt++; 2417 if (existing->prog == include_prog) 2418 return -EEXIST; 2419 } 2420 } 2421 2422 if (exclude_prog && !found_exclude) 2423 return -ENOENT; 2424 2425 /* How many progs (not NULL) will be in the new array? */ 2426 new_prog_cnt = carry_prog_cnt; 2427 if (include_prog) 2428 new_prog_cnt += 1; 2429 2430 /* Do we have any prog (not NULL) in the new array? */ 2431 if (!new_prog_cnt) { 2432 *new_array = NULL; 2433 return 0; 2434 } 2435 2436 /* +1 as the end of prog_array is marked with NULL */ 2437 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2438 if (!array) 2439 return -ENOMEM; 2440 new = array->items; 2441 2442 /* Fill in the new prog array */ 2443 if (carry_prog_cnt) { 2444 existing = old_array->items; 2445 for (; existing->prog; existing++) { 2446 if (existing->prog == exclude_prog || 2447 existing->prog == &dummy_bpf_prog.prog) 2448 continue; 2449 2450 new->prog = existing->prog; 2451 new->bpf_cookie = existing->bpf_cookie; 2452 new++; 2453 } 2454 } 2455 if (include_prog) { 2456 new->prog = include_prog; 2457 new->bpf_cookie = bpf_cookie; 2458 new++; 2459 } 2460 new->prog = NULL; 2461 *new_array = array; 2462 return 0; 2463 } 2464 2465 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2466 u32 *prog_ids, u32 request_cnt, 2467 u32 *prog_cnt) 2468 { 2469 u32 cnt = 0; 2470 2471 if (array) 2472 cnt = bpf_prog_array_length(array); 2473 2474 *prog_cnt = cnt; 2475 2476 /* return early if user requested only program count or nothing to copy */ 2477 if (!request_cnt || !cnt) 2478 return 0; 2479 2480 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2481 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2482 : 0; 2483 } 2484 2485 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2486 struct bpf_map **used_maps, u32 len) 2487 { 2488 struct bpf_map *map; 2489 u32 i; 2490 2491 for (i = 0; i < len; i++) { 2492 map = used_maps[i]; 2493 if (map->ops->map_poke_untrack) 2494 map->ops->map_poke_untrack(map, aux); 2495 bpf_map_put(map); 2496 } 2497 } 2498 2499 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2500 { 2501 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2502 kfree(aux->used_maps); 2503 } 2504 2505 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2506 struct btf_mod_pair *used_btfs, u32 len) 2507 { 2508 #ifdef CONFIG_BPF_SYSCALL 2509 struct btf_mod_pair *btf_mod; 2510 u32 i; 2511 2512 for (i = 0; i < len; i++) { 2513 btf_mod = &used_btfs[i]; 2514 if (btf_mod->module) 2515 module_put(btf_mod->module); 2516 btf_put(btf_mod->btf); 2517 } 2518 #endif 2519 } 2520 2521 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2522 { 2523 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2524 kfree(aux->used_btfs); 2525 } 2526 2527 static void bpf_prog_free_deferred(struct work_struct *work) 2528 { 2529 struct bpf_prog_aux *aux; 2530 int i; 2531 2532 aux = container_of(work, struct bpf_prog_aux, work); 2533 #ifdef CONFIG_BPF_SYSCALL 2534 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2535 #endif 2536 #ifdef CONFIG_CGROUP_BPF 2537 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2538 bpf_cgroup_atype_put(aux->cgroup_atype); 2539 #endif 2540 bpf_free_used_maps(aux); 2541 bpf_free_used_btfs(aux); 2542 if (bpf_prog_is_dev_bound(aux)) 2543 bpf_prog_offload_destroy(aux->prog); 2544 #ifdef CONFIG_PERF_EVENTS 2545 if (aux->prog->has_callchain_buf) 2546 put_callchain_buffers(); 2547 #endif 2548 if (aux->dst_trampoline) 2549 bpf_trampoline_put(aux->dst_trampoline); 2550 for (i = 0; i < aux->func_cnt; i++) { 2551 /* We can just unlink the subprog poke descriptor table as 2552 * it was originally linked to the main program and is also 2553 * released along with it. 2554 */ 2555 aux->func[i]->aux->poke_tab = NULL; 2556 bpf_jit_free(aux->func[i]); 2557 } 2558 if (aux->func_cnt) { 2559 kfree(aux->func); 2560 bpf_prog_unlock_free(aux->prog); 2561 } else { 2562 bpf_jit_free(aux->prog); 2563 } 2564 } 2565 2566 void bpf_prog_free(struct bpf_prog *fp) 2567 { 2568 struct bpf_prog_aux *aux = fp->aux; 2569 2570 if (aux->dst_prog) 2571 bpf_prog_put(aux->dst_prog); 2572 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2573 schedule_work(&aux->work); 2574 } 2575 EXPORT_SYMBOL_GPL(bpf_prog_free); 2576 2577 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2578 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2579 2580 void bpf_user_rnd_init_once(void) 2581 { 2582 prandom_init_once(&bpf_user_rnd_state); 2583 } 2584 2585 BPF_CALL_0(bpf_user_rnd_u32) 2586 { 2587 /* Should someone ever have the rather unwise idea to use some 2588 * of the registers passed into this function, then note that 2589 * this function is called from native eBPF and classic-to-eBPF 2590 * transformations. Register assignments from both sides are 2591 * different, f.e. classic always sets fn(ctx, A, X) here. 2592 */ 2593 struct rnd_state *state; 2594 u32 res; 2595 2596 state = &get_cpu_var(bpf_user_rnd_state); 2597 res = prandom_u32_state(state); 2598 put_cpu_var(bpf_user_rnd_state); 2599 2600 return res; 2601 } 2602 2603 BPF_CALL_0(bpf_get_raw_cpu_id) 2604 { 2605 return raw_smp_processor_id(); 2606 } 2607 2608 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2609 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2610 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2611 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2612 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2613 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2614 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2615 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2616 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2617 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2618 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2619 2620 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2621 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2622 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2623 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2624 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2625 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2626 2627 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2628 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2629 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2630 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2631 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2632 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2633 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2634 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2635 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2636 const struct bpf_func_proto bpf_set_retval_proto __weak; 2637 const struct bpf_func_proto bpf_get_retval_proto __weak; 2638 2639 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2640 { 2641 return NULL; 2642 } 2643 2644 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2645 { 2646 return NULL; 2647 } 2648 2649 u64 __weak 2650 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2651 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2652 { 2653 return -ENOTSUPP; 2654 } 2655 EXPORT_SYMBOL_GPL(bpf_event_output); 2656 2657 /* Always built-in helper functions. */ 2658 const struct bpf_func_proto bpf_tail_call_proto = { 2659 .func = NULL, 2660 .gpl_only = false, 2661 .ret_type = RET_VOID, 2662 .arg1_type = ARG_PTR_TO_CTX, 2663 .arg2_type = ARG_CONST_MAP_PTR, 2664 .arg3_type = ARG_ANYTHING, 2665 }; 2666 2667 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2668 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2669 * eBPF and implicitly also cBPF can get JITed! 2670 */ 2671 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2672 { 2673 return prog; 2674 } 2675 2676 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2677 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2678 */ 2679 void __weak bpf_jit_compile(struct bpf_prog *prog) 2680 { 2681 } 2682 2683 bool __weak bpf_helper_changes_pkt_data(void *func) 2684 { 2685 return false; 2686 } 2687 2688 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2689 * analysis code and wants explicit zero extension inserted by verifier. 2690 * Otherwise, return FALSE. 2691 * 2692 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2693 * you don't override this. JITs that don't want these extra insns can detect 2694 * them using insn_is_zext. 2695 */ 2696 bool __weak bpf_jit_needs_zext(void) 2697 { 2698 return false; 2699 } 2700 2701 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 2702 bool __weak bpf_jit_supports_subprog_tailcalls(void) 2703 { 2704 return false; 2705 } 2706 2707 bool __weak bpf_jit_supports_kfunc_call(void) 2708 { 2709 return false; 2710 } 2711 2712 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2713 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2714 */ 2715 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2716 int len) 2717 { 2718 return -EFAULT; 2719 } 2720 2721 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2722 void *addr1, void *addr2) 2723 { 2724 return -ENOTSUPP; 2725 } 2726 2727 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 2728 { 2729 return ERR_PTR(-ENOTSUPP); 2730 } 2731 2732 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 2733 { 2734 return -ENOTSUPP; 2735 } 2736 2737 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2738 EXPORT_SYMBOL(bpf_stats_enabled_key); 2739 2740 /* All definitions of tracepoints related to BPF. */ 2741 #define CREATE_TRACE_POINTS 2742 #include <linux/bpf_trace.h> 2743 2744 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2745 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2746