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 #include <linux/bpf_mem_alloc.h> 38 #include <linux/memcontrol.h> 39 40 #include <asm/barrier.h> 41 #include <asm/unaligned.h> 42 43 /* Registers */ 44 #define BPF_R0 regs[BPF_REG_0] 45 #define BPF_R1 regs[BPF_REG_1] 46 #define BPF_R2 regs[BPF_REG_2] 47 #define BPF_R3 regs[BPF_REG_3] 48 #define BPF_R4 regs[BPF_REG_4] 49 #define BPF_R5 regs[BPF_REG_5] 50 #define BPF_R6 regs[BPF_REG_6] 51 #define BPF_R7 regs[BPF_REG_7] 52 #define BPF_R8 regs[BPF_REG_8] 53 #define BPF_R9 regs[BPF_REG_9] 54 #define BPF_R10 regs[BPF_REG_10] 55 56 /* Named registers */ 57 #define DST regs[insn->dst_reg] 58 #define SRC regs[insn->src_reg] 59 #define FP regs[BPF_REG_FP] 60 #define AX regs[BPF_REG_AX] 61 #define ARG1 regs[BPF_REG_ARG1] 62 #define CTX regs[BPF_REG_CTX] 63 #define IMM insn->imm 64 65 struct bpf_mem_alloc bpf_global_ma; 66 bool bpf_global_ma_set; 67 68 /* No hurry in this branch 69 * 70 * Exported for the bpf jit load helper. 71 */ 72 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 73 { 74 u8 *ptr = NULL; 75 76 if (k >= SKF_NET_OFF) { 77 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 78 } else if (k >= SKF_LL_OFF) { 79 if (unlikely(!skb_mac_header_was_set(skb))) 80 return NULL; 81 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 82 } 83 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 84 return ptr; 85 86 return NULL; 87 } 88 89 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 90 { 91 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 92 struct bpf_prog_aux *aux; 93 struct bpf_prog *fp; 94 95 size = round_up(size, PAGE_SIZE); 96 fp = __vmalloc(size, gfp_flags); 97 if (fp == NULL) 98 return NULL; 99 100 aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 101 if (aux == NULL) { 102 vfree(fp); 103 return NULL; 104 } 105 fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 106 if (!fp->active) { 107 vfree(fp); 108 kfree(aux); 109 return NULL; 110 } 111 112 fp->pages = size / PAGE_SIZE; 113 fp->aux = aux; 114 fp->aux->prog = fp; 115 fp->jit_requested = ebpf_jit_enabled(); 116 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 117 #ifdef CONFIG_CGROUP_BPF 118 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 119 #endif 120 121 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 122 mutex_init(&fp->aux->used_maps_mutex); 123 mutex_init(&fp->aux->dst_mutex); 124 125 return fp; 126 } 127 128 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 129 { 130 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 131 struct bpf_prog *prog; 132 int cpu; 133 134 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 135 if (!prog) 136 return NULL; 137 138 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 139 if (!prog->stats) { 140 free_percpu(prog->active); 141 kfree(prog->aux); 142 vfree(prog); 143 return NULL; 144 } 145 146 for_each_possible_cpu(cpu) { 147 struct bpf_prog_stats *pstats; 148 149 pstats = per_cpu_ptr(prog->stats, cpu); 150 u64_stats_init(&pstats->syncp); 151 } 152 return prog; 153 } 154 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 155 156 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 157 { 158 if (!prog->aux->nr_linfo || !prog->jit_requested) 159 return 0; 160 161 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 162 sizeof(*prog->aux->jited_linfo), 163 bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN)); 164 if (!prog->aux->jited_linfo) 165 return -ENOMEM; 166 167 return 0; 168 } 169 170 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 171 { 172 if (prog->aux->jited_linfo && 173 (!prog->jited || !prog->aux->jited_linfo[0])) { 174 kvfree(prog->aux->jited_linfo); 175 prog->aux->jited_linfo = NULL; 176 } 177 178 kfree(prog->aux->kfunc_tab); 179 prog->aux->kfunc_tab = NULL; 180 } 181 182 /* The jit engine is responsible to provide an array 183 * for insn_off to the jited_off mapping (insn_to_jit_off). 184 * 185 * The idx to this array is the insn_off. Hence, the insn_off 186 * here is relative to the prog itself instead of the main prog. 187 * This array has one entry for each xlated bpf insn. 188 * 189 * jited_off is the byte off to the end of the jited insn. 190 * 191 * Hence, with 192 * insn_start: 193 * The first bpf insn off of the prog. The insn off 194 * here is relative to the main prog. 195 * e.g. if prog is a subprog, insn_start > 0 196 * linfo_idx: 197 * The prog's idx to prog->aux->linfo and jited_linfo 198 * 199 * jited_linfo[linfo_idx] = prog->bpf_func 200 * 201 * For i > linfo_idx, 202 * 203 * jited_linfo[i] = prog->bpf_func + 204 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 205 */ 206 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 207 const u32 *insn_to_jit_off) 208 { 209 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 210 const struct bpf_line_info *linfo; 211 void **jited_linfo; 212 213 if (!prog->aux->jited_linfo) 214 /* Userspace did not provide linfo */ 215 return; 216 217 linfo_idx = prog->aux->linfo_idx; 218 linfo = &prog->aux->linfo[linfo_idx]; 219 insn_start = linfo[0].insn_off; 220 insn_end = insn_start + prog->len; 221 222 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 223 jited_linfo[0] = prog->bpf_func; 224 225 nr_linfo = prog->aux->nr_linfo - linfo_idx; 226 227 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 228 /* The verifier ensures that linfo[i].insn_off is 229 * strictly increasing 230 */ 231 jited_linfo[i] = prog->bpf_func + 232 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 233 } 234 235 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 236 gfp_t gfp_extra_flags) 237 { 238 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 239 struct bpf_prog *fp; 240 u32 pages; 241 242 size = round_up(size, PAGE_SIZE); 243 pages = size / PAGE_SIZE; 244 if (pages <= fp_old->pages) 245 return fp_old; 246 247 fp = __vmalloc(size, gfp_flags); 248 if (fp) { 249 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 250 fp->pages = pages; 251 fp->aux->prog = fp; 252 253 /* We keep fp->aux from fp_old around in the new 254 * reallocated structure. 255 */ 256 fp_old->aux = NULL; 257 fp_old->stats = NULL; 258 fp_old->active = NULL; 259 __bpf_prog_free(fp_old); 260 } 261 262 return fp; 263 } 264 265 void __bpf_prog_free(struct bpf_prog *fp) 266 { 267 if (fp->aux) { 268 mutex_destroy(&fp->aux->used_maps_mutex); 269 mutex_destroy(&fp->aux->dst_mutex); 270 kfree(fp->aux->poke_tab); 271 kfree(fp->aux); 272 } 273 free_percpu(fp->stats); 274 free_percpu(fp->active); 275 vfree(fp); 276 } 277 278 int bpf_prog_calc_tag(struct bpf_prog *fp) 279 { 280 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 281 u32 raw_size = bpf_prog_tag_scratch_size(fp); 282 u32 digest[SHA1_DIGEST_WORDS]; 283 u32 ws[SHA1_WORKSPACE_WORDS]; 284 u32 i, bsize, psize, blocks; 285 struct bpf_insn *dst; 286 bool was_ld_map; 287 u8 *raw, *todo; 288 __be32 *result; 289 __be64 *bits; 290 291 raw = vmalloc(raw_size); 292 if (!raw) 293 return -ENOMEM; 294 295 sha1_init(digest); 296 memset(ws, 0, sizeof(ws)); 297 298 /* We need to take out the map fd for the digest calculation 299 * since they are unstable from user space side. 300 */ 301 dst = (void *)raw; 302 for (i = 0, was_ld_map = false; i < fp->len; i++) { 303 dst[i] = fp->insnsi[i]; 304 if (!was_ld_map && 305 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 306 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 307 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 308 was_ld_map = true; 309 dst[i].imm = 0; 310 } else if (was_ld_map && 311 dst[i].code == 0 && 312 dst[i].dst_reg == 0 && 313 dst[i].src_reg == 0 && 314 dst[i].off == 0) { 315 was_ld_map = false; 316 dst[i].imm = 0; 317 } else { 318 was_ld_map = false; 319 } 320 } 321 322 psize = bpf_prog_insn_size(fp); 323 memset(&raw[psize], 0, raw_size - psize); 324 raw[psize++] = 0x80; 325 326 bsize = round_up(psize, SHA1_BLOCK_SIZE); 327 blocks = bsize / SHA1_BLOCK_SIZE; 328 todo = raw; 329 if (bsize - psize >= sizeof(__be64)) { 330 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 331 } else { 332 bits = (__be64 *)(todo + bsize + bits_offset); 333 blocks++; 334 } 335 *bits = cpu_to_be64((psize - 1) << 3); 336 337 while (blocks--) { 338 sha1_transform(digest, todo, ws); 339 todo += SHA1_BLOCK_SIZE; 340 } 341 342 result = (__force __be32 *)digest; 343 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 344 result[i] = cpu_to_be32(digest[i]); 345 memcpy(fp->tag, result, sizeof(fp->tag)); 346 347 vfree(raw); 348 return 0; 349 } 350 351 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 352 s32 end_new, s32 curr, const bool probe_pass) 353 { 354 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 355 s32 delta = end_new - end_old; 356 s64 imm = insn->imm; 357 358 if (curr < pos && curr + imm + 1 >= end_old) 359 imm += delta; 360 else if (curr >= end_new && curr + imm + 1 < end_new) 361 imm -= delta; 362 if (imm < imm_min || imm > imm_max) 363 return -ERANGE; 364 if (!probe_pass) 365 insn->imm = imm; 366 return 0; 367 } 368 369 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 370 s32 end_new, s32 curr, const bool probe_pass) 371 { 372 const s32 off_min = S16_MIN, off_max = S16_MAX; 373 s32 delta = end_new - end_old; 374 s32 off = insn->off; 375 376 if (curr < pos && curr + off + 1 >= end_old) 377 off += delta; 378 else if (curr >= end_new && curr + off + 1 < end_new) 379 off -= delta; 380 if (off < off_min || off > off_max) 381 return -ERANGE; 382 if (!probe_pass) 383 insn->off = off; 384 return 0; 385 } 386 387 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 388 s32 end_new, const bool probe_pass) 389 { 390 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 391 struct bpf_insn *insn = prog->insnsi; 392 int ret = 0; 393 394 for (i = 0; i < insn_cnt; i++, insn++) { 395 u8 code; 396 397 /* In the probing pass we still operate on the original, 398 * unpatched image in order to check overflows before we 399 * do any other adjustments. Therefore skip the patchlet. 400 */ 401 if (probe_pass && i == pos) { 402 i = end_new; 403 insn = prog->insnsi + end_old; 404 } 405 if (bpf_pseudo_func(insn)) { 406 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 407 end_new, i, probe_pass); 408 if (ret) 409 return ret; 410 continue; 411 } 412 code = insn->code; 413 if ((BPF_CLASS(code) != BPF_JMP && 414 BPF_CLASS(code) != BPF_JMP32) || 415 BPF_OP(code) == BPF_EXIT) 416 continue; 417 /* Adjust offset of jmps if we cross patch boundaries. */ 418 if (BPF_OP(code) == BPF_CALL) { 419 if (insn->src_reg != BPF_PSEUDO_CALL) 420 continue; 421 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 422 end_new, i, probe_pass); 423 } else { 424 ret = bpf_adj_delta_to_off(insn, pos, end_old, 425 end_new, i, probe_pass); 426 } 427 if (ret) 428 break; 429 } 430 431 return ret; 432 } 433 434 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 435 { 436 struct bpf_line_info *linfo; 437 u32 i, nr_linfo; 438 439 nr_linfo = prog->aux->nr_linfo; 440 if (!nr_linfo || !delta) 441 return; 442 443 linfo = prog->aux->linfo; 444 445 for (i = 0; i < nr_linfo; i++) 446 if (off < linfo[i].insn_off) 447 break; 448 449 /* Push all off < linfo[i].insn_off by delta */ 450 for (; i < nr_linfo; i++) 451 linfo[i].insn_off += delta; 452 } 453 454 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 455 const struct bpf_insn *patch, u32 len) 456 { 457 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 458 const u32 cnt_max = S16_MAX; 459 struct bpf_prog *prog_adj; 460 int err; 461 462 /* Since our patchlet doesn't expand the image, we're done. */ 463 if (insn_delta == 0) { 464 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 465 return prog; 466 } 467 468 insn_adj_cnt = prog->len + insn_delta; 469 470 /* Reject anything that would potentially let the insn->off 471 * target overflow when we have excessive program expansions. 472 * We need to probe here before we do any reallocation where 473 * we afterwards may not fail anymore. 474 */ 475 if (insn_adj_cnt > cnt_max && 476 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 477 return ERR_PTR(err); 478 479 /* Several new instructions need to be inserted. Make room 480 * for them. Likely, there's no need for a new allocation as 481 * last page could have large enough tailroom. 482 */ 483 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 484 GFP_USER); 485 if (!prog_adj) 486 return ERR_PTR(-ENOMEM); 487 488 prog_adj->len = insn_adj_cnt; 489 490 /* Patching happens in 3 steps: 491 * 492 * 1) Move over tail of insnsi from next instruction onwards, 493 * so we can patch the single target insn with one or more 494 * new ones (patching is always from 1 to n insns, n > 0). 495 * 2) Inject new instructions at the target location. 496 * 3) Adjust branch offsets if necessary. 497 */ 498 insn_rest = insn_adj_cnt - off - len; 499 500 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 501 sizeof(*patch) * insn_rest); 502 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 503 504 /* We are guaranteed to not fail at this point, otherwise 505 * the ship has sailed to reverse to the original state. An 506 * overflow cannot happen at this point. 507 */ 508 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 509 510 bpf_adj_linfo(prog_adj, off, insn_delta); 511 512 return prog_adj; 513 } 514 515 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 516 { 517 /* Branch offsets can't overflow when program is shrinking, no need 518 * to call bpf_adj_branches(..., true) here 519 */ 520 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 521 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 522 prog->len -= cnt; 523 524 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 525 } 526 527 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 528 { 529 int i; 530 531 for (i = 0; i < fp->aux->func_cnt; i++) 532 bpf_prog_kallsyms_del(fp->aux->func[i]); 533 } 534 535 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 536 { 537 bpf_prog_kallsyms_del_subprogs(fp); 538 bpf_prog_kallsyms_del(fp); 539 } 540 541 #ifdef CONFIG_BPF_JIT 542 /* All BPF JIT sysctl knobs here. */ 543 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 544 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 545 int bpf_jit_harden __read_mostly; 546 long bpf_jit_limit __read_mostly; 547 long bpf_jit_limit_max __read_mostly; 548 549 static void 550 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 551 { 552 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 553 554 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 555 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 556 } 557 558 static void 559 bpf_prog_ksym_set_name(struct bpf_prog *prog) 560 { 561 char *sym = prog->aux->ksym.name; 562 const char *end = sym + KSYM_NAME_LEN; 563 const struct btf_type *type; 564 const char *func_name; 565 566 BUILD_BUG_ON(sizeof("bpf_prog_") + 567 sizeof(prog->tag) * 2 + 568 /* name has been null terminated. 569 * We should need +1 for the '_' preceding 570 * the name. However, the null character 571 * is double counted between the name and the 572 * sizeof("bpf_prog_") above, so we omit 573 * the +1 here. 574 */ 575 sizeof(prog->aux->name) > KSYM_NAME_LEN); 576 577 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 578 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 579 580 /* prog->aux->name will be ignored if full btf name is available */ 581 if (prog->aux->func_info_cnt) { 582 type = btf_type_by_id(prog->aux->btf, 583 prog->aux->func_info[prog->aux->func_idx].type_id); 584 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 585 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 586 return; 587 } 588 589 if (prog->aux->name[0]) 590 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 591 else 592 *sym = 0; 593 } 594 595 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 596 { 597 return container_of(n, struct bpf_ksym, tnode)->start; 598 } 599 600 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 601 struct latch_tree_node *b) 602 { 603 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 604 } 605 606 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 607 { 608 unsigned long val = (unsigned long)key; 609 const struct bpf_ksym *ksym; 610 611 ksym = container_of(n, struct bpf_ksym, tnode); 612 613 if (val < ksym->start) 614 return -1; 615 if (val >= ksym->end) 616 return 1; 617 618 return 0; 619 } 620 621 static const struct latch_tree_ops bpf_tree_ops = { 622 .less = bpf_tree_less, 623 .comp = bpf_tree_comp, 624 }; 625 626 static DEFINE_SPINLOCK(bpf_lock); 627 static LIST_HEAD(bpf_kallsyms); 628 static struct latch_tree_root bpf_tree __cacheline_aligned; 629 630 void bpf_ksym_add(struct bpf_ksym *ksym) 631 { 632 spin_lock_bh(&bpf_lock); 633 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 634 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 635 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 636 spin_unlock_bh(&bpf_lock); 637 } 638 639 static void __bpf_ksym_del(struct bpf_ksym *ksym) 640 { 641 if (list_empty(&ksym->lnode)) 642 return; 643 644 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 645 list_del_rcu(&ksym->lnode); 646 } 647 648 void bpf_ksym_del(struct bpf_ksym *ksym) 649 { 650 spin_lock_bh(&bpf_lock); 651 __bpf_ksym_del(ksym); 652 spin_unlock_bh(&bpf_lock); 653 } 654 655 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 656 { 657 return fp->jited && !bpf_prog_was_classic(fp); 658 } 659 660 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 661 { 662 if (!bpf_prog_kallsyms_candidate(fp) || 663 !bpf_capable()) 664 return; 665 666 bpf_prog_ksym_set_addr(fp); 667 bpf_prog_ksym_set_name(fp); 668 fp->aux->ksym.prog = true; 669 670 bpf_ksym_add(&fp->aux->ksym); 671 } 672 673 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 674 { 675 if (!bpf_prog_kallsyms_candidate(fp)) 676 return; 677 678 bpf_ksym_del(&fp->aux->ksym); 679 } 680 681 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 682 { 683 struct latch_tree_node *n; 684 685 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 686 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 687 } 688 689 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 690 unsigned long *off, char *sym) 691 { 692 struct bpf_ksym *ksym; 693 char *ret = NULL; 694 695 rcu_read_lock(); 696 ksym = bpf_ksym_find(addr); 697 if (ksym) { 698 unsigned long symbol_start = ksym->start; 699 unsigned long symbol_end = ksym->end; 700 701 strncpy(sym, ksym->name, KSYM_NAME_LEN); 702 703 ret = sym; 704 if (size) 705 *size = symbol_end - symbol_start; 706 if (off) 707 *off = addr - symbol_start; 708 } 709 rcu_read_unlock(); 710 711 return ret; 712 } 713 714 bool is_bpf_text_address(unsigned long addr) 715 { 716 bool ret; 717 718 rcu_read_lock(); 719 ret = bpf_ksym_find(addr) != NULL; 720 rcu_read_unlock(); 721 722 return ret; 723 } 724 725 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 726 { 727 struct bpf_ksym *ksym = bpf_ksym_find(addr); 728 729 return ksym && ksym->prog ? 730 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 731 NULL; 732 } 733 734 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 735 { 736 const struct exception_table_entry *e = NULL; 737 struct bpf_prog *prog; 738 739 rcu_read_lock(); 740 prog = bpf_prog_ksym_find(addr); 741 if (!prog) 742 goto out; 743 if (!prog->aux->num_exentries) 744 goto out; 745 746 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 747 out: 748 rcu_read_unlock(); 749 return e; 750 } 751 752 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 753 char *sym) 754 { 755 struct bpf_ksym *ksym; 756 unsigned int it = 0; 757 int ret = -ERANGE; 758 759 if (!bpf_jit_kallsyms_enabled()) 760 return ret; 761 762 rcu_read_lock(); 763 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 764 if (it++ != symnum) 765 continue; 766 767 strncpy(sym, ksym->name, KSYM_NAME_LEN); 768 769 *value = ksym->start; 770 *type = BPF_SYM_ELF_TYPE; 771 772 ret = 0; 773 break; 774 } 775 rcu_read_unlock(); 776 777 return ret; 778 } 779 780 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 781 struct bpf_jit_poke_descriptor *poke) 782 { 783 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 784 static const u32 poke_tab_max = 1024; 785 u32 slot = prog->aux->size_poke_tab; 786 u32 size = slot + 1; 787 788 if (size > poke_tab_max) 789 return -ENOSPC; 790 if (poke->tailcall_target || poke->tailcall_target_stable || 791 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 792 return -EINVAL; 793 794 switch (poke->reason) { 795 case BPF_POKE_REASON_TAIL_CALL: 796 if (!poke->tail_call.map) 797 return -EINVAL; 798 break; 799 default: 800 return -EINVAL; 801 } 802 803 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 804 if (!tab) 805 return -ENOMEM; 806 807 memcpy(&tab[slot], poke, sizeof(*poke)); 808 prog->aux->size_poke_tab = size; 809 prog->aux->poke_tab = tab; 810 811 return slot; 812 } 813 814 /* 815 * BPF program pack allocator. 816 * 817 * Most BPF programs are pretty small. Allocating a hole page for each 818 * program is sometime a waste. Many small bpf program also adds pressure 819 * to instruction TLB. To solve this issue, we introduce a BPF program pack 820 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 821 * to host BPF programs. 822 */ 823 #define BPF_PROG_CHUNK_SHIFT 6 824 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 825 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 826 827 struct bpf_prog_pack { 828 struct list_head list; 829 void *ptr; 830 unsigned long bitmap[]; 831 }; 832 833 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) 834 { 835 memset(area, 0, size); 836 } 837 838 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 839 840 static DEFINE_MUTEX(pack_mutex); 841 static LIST_HEAD(pack_list); 842 843 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 844 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 845 */ 846 #ifdef PMD_SIZE 847 #define BPF_PROG_PACK_SIZE (PMD_SIZE * num_possible_nodes()) 848 #else 849 #define BPF_PROG_PACK_SIZE PAGE_SIZE 850 #endif 851 852 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 853 854 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 855 { 856 struct bpf_prog_pack *pack; 857 858 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), 859 GFP_KERNEL); 860 if (!pack) 861 return NULL; 862 pack->ptr = module_alloc(BPF_PROG_PACK_SIZE); 863 if (!pack->ptr) { 864 kfree(pack); 865 return NULL; 866 } 867 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 868 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 869 list_add_tail(&pack->list, &pack_list); 870 871 set_vm_flush_reset_perms(pack->ptr); 872 set_memory_rox((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 873 return pack; 874 } 875 876 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 877 { 878 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 879 struct bpf_prog_pack *pack; 880 unsigned long pos; 881 void *ptr = NULL; 882 883 mutex_lock(&pack_mutex); 884 if (size > BPF_PROG_PACK_SIZE) { 885 size = round_up(size, PAGE_SIZE); 886 ptr = module_alloc(size); 887 if (ptr) { 888 bpf_fill_ill_insns(ptr, size); 889 set_vm_flush_reset_perms(ptr); 890 set_memory_rox((unsigned long)ptr, size / PAGE_SIZE); 891 } 892 goto out; 893 } 894 list_for_each_entry(pack, &pack_list, list) { 895 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 896 nbits, 0); 897 if (pos < BPF_PROG_CHUNK_COUNT) 898 goto found_free_area; 899 } 900 901 pack = alloc_new_pack(bpf_fill_ill_insns); 902 if (!pack) 903 goto out; 904 905 pos = 0; 906 907 found_free_area: 908 bitmap_set(pack->bitmap, pos, nbits); 909 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 910 911 out: 912 mutex_unlock(&pack_mutex); 913 return ptr; 914 } 915 916 void bpf_prog_pack_free(struct bpf_binary_header *hdr) 917 { 918 struct bpf_prog_pack *pack = NULL, *tmp; 919 unsigned int nbits; 920 unsigned long pos; 921 922 mutex_lock(&pack_mutex); 923 if (hdr->size > BPF_PROG_PACK_SIZE) { 924 module_memfree(hdr); 925 goto out; 926 } 927 928 list_for_each_entry(tmp, &pack_list, list) { 929 if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) { 930 pack = tmp; 931 break; 932 } 933 } 934 935 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 936 goto out; 937 938 nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size); 939 pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; 940 941 WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size), 942 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 943 944 bitmap_clear(pack->bitmap, pos, nbits); 945 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 946 BPF_PROG_CHUNK_COUNT, 0) == 0) { 947 list_del(&pack->list); 948 module_memfree(pack->ptr); 949 kfree(pack); 950 } 951 out: 952 mutex_unlock(&pack_mutex); 953 } 954 955 static atomic_long_t bpf_jit_current; 956 957 /* Can be overridden by an arch's JIT compiler if it has a custom, 958 * dedicated BPF backend memory area, or if neither of the two 959 * below apply. 960 */ 961 u64 __weak bpf_jit_alloc_exec_limit(void) 962 { 963 #if defined(MODULES_VADDR) 964 return MODULES_END - MODULES_VADDR; 965 #else 966 return VMALLOC_END - VMALLOC_START; 967 #endif 968 } 969 970 static int __init bpf_jit_charge_init(void) 971 { 972 /* Only used as heuristic here to derive limit. */ 973 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 974 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2, 975 PAGE_SIZE), LONG_MAX); 976 return 0; 977 } 978 pure_initcall(bpf_jit_charge_init); 979 980 int bpf_jit_charge_modmem(u32 size) 981 { 982 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { 983 if (!bpf_capable()) { 984 atomic_long_sub(size, &bpf_jit_current); 985 return -EPERM; 986 } 987 } 988 989 return 0; 990 } 991 992 void bpf_jit_uncharge_modmem(u32 size) 993 { 994 atomic_long_sub(size, &bpf_jit_current); 995 } 996 997 void *__weak bpf_jit_alloc_exec(unsigned long size) 998 { 999 return module_alloc(size); 1000 } 1001 1002 void __weak bpf_jit_free_exec(void *addr) 1003 { 1004 module_memfree(addr); 1005 } 1006 1007 struct bpf_binary_header * 1008 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1009 unsigned int alignment, 1010 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1011 { 1012 struct bpf_binary_header *hdr; 1013 u32 size, hole, start; 1014 1015 WARN_ON_ONCE(!is_power_of_2(alignment) || 1016 alignment > BPF_IMAGE_ALIGNMENT); 1017 1018 /* Most of BPF filters are really small, but if some of them 1019 * fill a page, allow at least 128 extra bytes to insert a 1020 * random section of illegal instructions. 1021 */ 1022 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1023 1024 if (bpf_jit_charge_modmem(size)) 1025 return NULL; 1026 hdr = bpf_jit_alloc_exec(size); 1027 if (!hdr) { 1028 bpf_jit_uncharge_modmem(size); 1029 return NULL; 1030 } 1031 1032 /* Fill space with illegal/arch-dep instructions. */ 1033 bpf_fill_ill_insns(hdr, size); 1034 1035 hdr->size = size; 1036 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1037 PAGE_SIZE - sizeof(*hdr)); 1038 start = get_random_u32_below(hole) & ~(alignment - 1); 1039 1040 /* Leave a random number of instructions before BPF code. */ 1041 *image_ptr = &hdr->image[start]; 1042 1043 return hdr; 1044 } 1045 1046 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1047 { 1048 u32 size = hdr->size; 1049 1050 bpf_jit_free_exec(hdr); 1051 bpf_jit_uncharge_modmem(size); 1052 } 1053 1054 /* Allocate jit binary from bpf_prog_pack allocator. 1055 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1056 * to the memory. To solve this problem, a RW buffer is also allocated at 1057 * as the same time. The JIT engine should calculate offsets based on the 1058 * RO memory address, but write JITed program to the RW buffer. Once the 1059 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1060 * the JITed program to the RO memory. 1061 */ 1062 struct bpf_binary_header * 1063 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1064 unsigned int alignment, 1065 struct bpf_binary_header **rw_header, 1066 u8 **rw_image, 1067 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1068 { 1069 struct bpf_binary_header *ro_header; 1070 u32 size, hole, start; 1071 1072 WARN_ON_ONCE(!is_power_of_2(alignment) || 1073 alignment > BPF_IMAGE_ALIGNMENT); 1074 1075 /* add 16 bytes for a random section of illegal instructions */ 1076 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1077 1078 if (bpf_jit_charge_modmem(size)) 1079 return NULL; 1080 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1081 if (!ro_header) { 1082 bpf_jit_uncharge_modmem(size); 1083 return NULL; 1084 } 1085 1086 *rw_header = kvmalloc(size, GFP_KERNEL); 1087 if (!*rw_header) { 1088 bpf_arch_text_copy(&ro_header->size, &size, sizeof(size)); 1089 bpf_prog_pack_free(ro_header); 1090 bpf_jit_uncharge_modmem(size); 1091 return NULL; 1092 } 1093 1094 /* Fill space with illegal/arch-dep instructions. */ 1095 bpf_fill_ill_insns(*rw_header, size); 1096 (*rw_header)->size = size; 1097 1098 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1099 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1100 start = get_random_u32_below(hole) & ~(alignment - 1); 1101 1102 *image_ptr = &ro_header->image[start]; 1103 *rw_image = &(*rw_header)->image[start]; 1104 1105 return ro_header; 1106 } 1107 1108 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1109 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, 1110 struct bpf_binary_header *ro_header, 1111 struct bpf_binary_header *rw_header) 1112 { 1113 void *ptr; 1114 1115 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1116 1117 kvfree(rw_header); 1118 1119 if (IS_ERR(ptr)) { 1120 bpf_prog_pack_free(ro_header); 1121 return PTR_ERR(ptr); 1122 } 1123 return 0; 1124 } 1125 1126 /* bpf_jit_binary_pack_free is called in two different scenarios: 1127 * 1) when the program is freed after; 1128 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1129 * For case 2), we need to free both the RO memory and the RW buffer. 1130 * 1131 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1132 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1133 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1134 * bpf_arch_text_copy (when jit fails). 1135 */ 1136 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1137 struct bpf_binary_header *rw_header) 1138 { 1139 u32 size = ro_header->size; 1140 1141 bpf_prog_pack_free(ro_header); 1142 kvfree(rw_header); 1143 bpf_jit_uncharge_modmem(size); 1144 } 1145 1146 struct bpf_binary_header * 1147 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp) 1148 { 1149 unsigned long real_start = (unsigned long)fp->bpf_func; 1150 unsigned long addr; 1151 1152 addr = real_start & BPF_PROG_CHUNK_MASK; 1153 return (void *)addr; 1154 } 1155 1156 static inline struct bpf_binary_header * 1157 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1158 { 1159 unsigned long real_start = (unsigned long)fp->bpf_func; 1160 unsigned long addr; 1161 1162 addr = real_start & PAGE_MASK; 1163 return (void *)addr; 1164 } 1165 1166 /* This symbol is only overridden by archs that have different 1167 * requirements than the usual eBPF JITs, f.e. when they only 1168 * implement cBPF JIT, do not set images read-only, etc. 1169 */ 1170 void __weak bpf_jit_free(struct bpf_prog *fp) 1171 { 1172 if (fp->jited) { 1173 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1174 1175 bpf_jit_binary_free(hdr); 1176 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1177 } 1178 1179 bpf_prog_unlock_free(fp); 1180 } 1181 1182 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1183 const struct bpf_insn *insn, bool extra_pass, 1184 u64 *func_addr, bool *func_addr_fixed) 1185 { 1186 s16 off = insn->off; 1187 s32 imm = insn->imm; 1188 u8 *addr; 1189 1190 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1191 if (!*func_addr_fixed) { 1192 /* Place-holder address till the last pass has collected 1193 * all addresses for JITed subprograms in which case we 1194 * can pick them up from prog->aux. 1195 */ 1196 if (!extra_pass) 1197 addr = NULL; 1198 else if (prog->aux->func && 1199 off >= 0 && off < prog->aux->func_cnt) 1200 addr = (u8 *)prog->aux->func[off]->bpf_func; 1201 else 1202 return -EINVAL; 1203 } else { 1204 /* Address of a BPF helper call. Since part of the core 1205 * kernel, it's always at a fixed location. __bpf_call_base 1206 * and the helper with imm relative to it are both in core 1207 * kernel. 1208 */ 1209 addr = (u8 *)__bpf_call_base + imm; 1210 } 1211 1212 *func_addr = (unsigned long)addr; 1213 return 0; 1214 } 1215 1216 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1217 const struct bpf_insn *aux, 1218 struct bpf_insn *to_buff, 1219 bool emit_zext) 1220 { 1221 struct bpf_insn *to = to_buff; 1222 u32 imm_rnd = get_random_u32(); 1223 s16 off; 1224 1225 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1226 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1227 1228 /* Constraints on AX register: 1229 * 1230 * AX register is inaccessible from user space. It is mapped in 1231 * all JITs, and used here for constant blinding rewrites. It is 1232 * typically "stateless" meaning its contents are only valid within 1233 * the executed instruction, but not across several instructions. 1234 * There are a few exceptions however which are further detailed 1235 * below. 1236 * 1237 * Constant blinding is only used by JITs, not in the interpreter. 1238 * The interpreter uses AX in some occasions as a local temporary 1239 * register e.g. in DIV or MOD instructions. 1240 * 1241 * In restricted circumstances, the verifier can also use the AX 1242 * register for rewrites as long as they do not interfere with 1243 * the above cases! 1244 */ 1245 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1246 goto out; 1247 1248 if (from->imm == 0 && 1249 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1250 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1251 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1252 goto out; 1253 } 1254 1255 switch (from->code) { 1256 case BPF_ALU | BPF_ADD | BPF_K: 1257 case BPF_ALU | BPF_SUB | BPF_K: 1258 case BPF_ALU | BPF_AND | BPF_K: 1259 case BPF_ALU | BPF_OR | BPF_K: 1260 case BPF_ALU | BPF_XOR | BPF_K: 1261 case BPF_ALU | BPF_MUL | BPF_K: 1262 case BPF_ALU | BPF_MOV | BPF_K: 1263 case BPF_ALU | BPF_DIV | BPF_K: 1264 case BPF_ALU | BPF_MOD | BPF_K: 1265 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1266 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1267 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1268 break; 1269 1270 case BPF_ALU64 | BPF_ADD | BPF_K: 1271 case BPF_ALU64 | BPF_SUB | BPF_K: 1272 case BPF_ALU64 | BPF_AND | BPF_K: 1273 case BPF_ALU64 | BPF_OR | BPF_K: 1274 case BPF_ALU64 | BPF_XOR | BPF_K: 1275 case BPF_ALU64 | BPF_MUL | BPF_K: 1276 case BPF_ALU64 | BPF_MOV | BPF_K: 1277 case BPF_ALU64 | BPF_DIV | BPF_K: 1278 case BPF_ALU64 | BPF_MOD | BPF_K: 1279 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1280 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1281 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1282 break; 1283 1284 case BPF_JMP | BPF_JEQ | BPF_K: 1285 case BPF_JMP | BPF_JNE | BPF_K: 1286 case BPF_JMP | BPF_JGT | BPF_K: 1287 case BPF_JMP | BPF_JLT | BPF_K: 1288 case BPF_JMP | BPF_JGE | BPF_K: 1289 case BPF_JMP | BPF_JLE | BPF_K: 1290 case BPF_JMP | BPF_JSGT | BPF_K: 1291 case BPF_JMP | BPF_JSLT | BPF_K: 1292 case BPF_JMP | BPF_JSGE | BPF_K: 1293 case BPF_JMP | BPF_JSLE | BPF_K: 1294 case BPF_JMP | BPF_JSET | BPF_K: 1295 /* Accommodate for extra offset in case of a backjump. */ 1296 off = from->off; 1297 if (off < 0) 1298 off -= 2; 1299 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1300 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1301 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1302 break; 1303 1304 case BPF_JMP32 | BPF_JEQ | BPF_K: 1305 case BPF_JMP32 | BPF_JNE | BPF_K: 1306 case BPF_JMP32 | BPF_JGT | BPF_K: 1307 case BPF_JMP32 | BPF_JLT | BPF_K: 1308 case BPF_JMP32 | BPF_JGE | BPF_K: 1309 case BPF_JMP32 | BPF_JLE | BPF_K: 1310 case BPF_JMP32 | BPF_JSGT | BPF_K: 1311 case BPF_JMP32 | BPF_JSLT | BPF_K: 1312 case BPF_JMP32 | BPF_JSGE | BPF_K: 1313 case BPF_JMP32 | BPF_JSLE | BPF_K: 1314 case BPF_JMP32 | BPF_JSET | BPF_K: 1315 /* Accommodate for extra offset in case of a backjump. */ 1316 off = from->off; 1317 if (off < 0) 1318 off -= 2; 1319 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1320 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1321 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1322 off); 1323 break; 1324 1325 case BPF_LD | BPF_IMM | BPF_DW: 1326 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1327 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1328 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1329 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1330 break; 1331 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1332 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1333 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1334 if (emit_zext) 1335 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1336 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1337 break; 1338 1339 case BPF_ST | BPF_MEM | BPF_DW: 1340 case BPF_ST | BPF_MEM | BPF_W: 1341 case BPF_ST | BPF_MEM | BPF_H: 1342 case BPF_ST | BPF_MEM | BPF_B: 1343 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1344 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1345 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1346 break; 1347 } 1348 out: 1349 return to - to_buff; 1350 } 1351 1352 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1353 gfp_t gfp_extra_flags) 1354 { 1355 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1356 struct bpf_prog *fp; 1357 1358 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1359 if (fp != NULL) { 1360 /* aux->prog still points to the fp_other one, so 1361 * when promoting the clone to the real program, 1362 * this still needs to be adapted. 1363 */ 1364 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1365 } 1366 1367 return fp; 1368 } 1369 1370 static void bpf_prog_clone_free(struct bpf_prog *fp) 1371 { 1372 /* aux was stolen by the other clone, so we cannot free 1373 * it from this path! It will be freed eventually by the 1374 * other program on release. 1375 * 1376 * At this point, we don't need a deferred release since 1377 * clone is guaranteed to not be locked. 1378 */ 1379 fp->aux = NULL; 1380 fp->stats = NULL; 1381 fp->active = NULL; 1382 __bpf_prog_free(fp); 1383 } 1384 1385 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1386 { 1387 /* We have to repoint aux->prog to self, as we don't 1388 * know whether fp here is the clone or the original. 1389 */ 1390 fp->aux->prog = fp; 1391 bpf_prog_clone_free(fp_other); 1392 } 1393 1394 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1395 { 1396 struct bpf_insn insn_buff[16], aux[2]; 1397 struct bpf_prog *clone, *tmp; 1398 int insn_delta, insn_cnt; 1399 struct bpf_insn *insn; 1400 int i, rewritten; 1401 1402 if (!prog->blinding_requested || prog->blinded) 1403 return prog; 1404 1405 clone = bpf_prog_clone_create(prog, GFP_USER); 1406 if (!clone) 1407 return ERR_PTR(-ENOMEM); 1408 1409 insn_cnt = clone->len; 1410 insn = clone->insnsi; 1411 1412 for (i = 0; i < insn_cnt; i++, insn++) { 1413 if (bpf_pseudo_func(insn)) { 1414 /* ld_imm64 with an address of bpf subprog is not 1415 * a user controlled constant. Don't randomize it, 1416 * since it will conflict with jit_subprogs() logic. 1417 */ 1418 insn++; 1419 i++; 1420 continue; 1421 } 1422 1423 /* We temporarily need to hold the original ld64 insn 1424 * so that we can still access the first part in the 1425 * second blinding run. 1426 */ 1427 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1428 insn[1].code == 0) 1429 memcpy(aux, insn, sizeof(aux)); 1430 1431 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1432 clone->aux->verifier_zext); 1433 if (!rewritten) 1434 continue; 1435 1436 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1437 if (IS_ERR(tmp)) { 1438 /* Patching may have repointed aux->prog during 1439 * realloc from the original one, so we need to 1440 * fix it up here on error. 1441 */ 1442 bpf_jit_prog_release_other(prog, clone); 1443 return tmp; 1444 } 1445 1446 clone = tmp; 1447 insn_delta = rewritten - 1; 1448 1449 /* Walk new program and skip insns we just inserted. */ 1450 insn = clone->insnsi + i + insn_delta; 1451 insn_cnt += insn_delta; 1452 i += insn_delta; 1453 } 1454 1455 clone->blinded = 1; 1456 return clone; 1457 } 1458 #endif /* CONFIG_BPF_JIT */ 1459 1460 /* Base function for offset calculation. Needs to go into .text section, 1461 * therefore keeping it non-static as well; will also be used by JITs 1462 * anyway later on, so do not let the compiler omit it. This also needs 1463 * to go into kallsyms for correlation from e.g. bpftool, so naming 1464 * must not change. 1465 */ 1466 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1467 { 1468 return 0; 1469 } 1470 EXPORT_SYMBOL_GPL(__bpf_call_base); 1471 1472 /* All UAPI available opcodes. */ 1473 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1474 /* 32 bit ALU operations. */ \ 1475 /* Register based. */ \ 1476 INSN_3(ALU, ADD, X), \ 1477 INSN_3(ALU, SUB, X), \ 1478 INSN_3(ALU, AND, X), \ 1479 INSN_3(ALU, OR, X), \ 1480 INSN_3(ALU, LSH, X), \ 1481 INSN_3(ALU, RSH, X), \ 1482 INSN_3(ALU, XOR, X), \ 1483 INSN_3(ALU, MUL, X), \ 1484 INSN_3(ALU, MOV, X), \ 1485 INSN_3(ALU, ARSH, X), \ 1486 INSN_3(ALU, DIV, X), \ 1487 INSN_3(ALU, MOD, X), \ 1488 INSN_2(ALU, NEG), \ 1489 INSN_3(ALU, END, TO_BE), \ 1490 INSN_3(ALU, END, TO_LE), \ 1491 /* Immediate based. */ \ 1492 INSN_3(ALU, ADD, K), \ 1493 INSN_3(ALU, SUB, K), \ 1494 INSN_3(ALU, AND, K), \ 1495 INSN_3(ALU, OR, K), \ 1496 INSN_3(ALU, LSH, K), \ 1497 INSN_3(ALU, RSH, K), \ 1498 INSN_3(ALU, XOR, K), \ 1499 INSN_3(ALU, MUL, K), \ 1500 INSN_3(ALU, MOV, K), \ 1501 INSN_3(ALU, ARSH, K), \ 1502 INSN_3(ALU, DIV, K), \ 1503 INSN_3(ALU, MOD, K), \ 1504 /* 64 bit ALU operations. */ \ 1505 /* Register based. */ \ 1506 INSN_3(ALU64, ADD, X), \ 1507 INSN_3(ALU64, SUB, X), \ 1508 INSN_3(ALU64, AND, X), \ 1509 INSN_3(ALU64, OR, X), \ 1510 INSN_3(ALU64, LSH, X), \ 1511 INSN_3(ALU64, RSH, X), \ 1512 INSN_3(ALU64, XOR, X), \ 1513 INSN_3(ALU64, MUL, X), \ 1514 INSN_3(ALU64, MOV, X), \ 1515 INSN_3(ALU64, ARSH, X), \ 1516 INSN_3(ALU64, DIV, X), \ 1517 INSN_3(ALU64, MOD, X), \ 1518 INSN_2(ALU64, NEG), \ 1519 /* Immediate based. */ \ 1520 INSN_3(ALU64, ADD, K), \ 1521 INSN_3(ALU64, SUB, K), \ 1522 INSN_3(ALU64, AND, K), \ 1523 INSN_3(ALU64, OR, K), \ 1524 INSN_3(ALU64, LSH, K), \ 1525 INSN_3(ALU64, RSH, K), \ 1526 INSN_3(ALU64, XOR, K), \ 1527 INSN_3(ALU64, MUL, K), \ 1528 INSN_3(ALU64, MOV, K), \ 1529 INSN_3(ALU64, ARSH, K), \ 1530 INSN_3(ALU64, DIV, K), \ 1531 INSN_3(ALU64, MOD, K), \ 1532 /* Call instruction. */ \ 1533 INSN_2(JMP, CALL), \ 1534 /* Exit instruction. */ \ 1535 INSN_2(JMP, EXIT), \ 1536 /* 32-bit Jump instructions. */ \ 1537 /* Register based. */ \ 1538 INSN_3(JMP32, JEQ, X), \ 1539 INSN_3(JMP32, JNE, X), \ 1540 INSN_3(JMP32, JGT, X), \ 1541 INSN_3(JMP32, JLT, X), \ 1542 INSN_3(JMP32, JGE, X), \ 1543 INSN_3(JMP32, JLE, X), \ 1544 INSN_3(JMP32, JSGT, X), \ 1545 INSN_3(JMP32, JSLT, X), \ 1546 INSN_3(JMP32, JSGE, X), \ 1547 INSN_3(JMP32, JSLE, X), \ 1548 INSN_3(JMP32, JSET, X), \ 1549 /* Immediate based. */ \ 1550 INSN_3(JMP32, JEQ, K), \ 1551 INSN_3(JMP32, JNE, K), \ 1552 INSN_3(JMP32, JGT, K), \ 1553 INSN_3(JMP32, JLT, K), \ 1554 INSN_3(JMP32, JGE, K), \ 1555 INSN_3(JMP32, JLE, K), \ 1556 INSN_3(JMP32, JSGT, K), \ 1557 INSN_3(JMP32, JSLT, K), \ 1558 INSN_3(JMP32, JSGE, K), \ 1559 INSN_3(JMP32, JSLE, K), \ 1560 INSN_3(JMP32, JSET, K), \ 1561 /* Jump instructions. */ \ 1562 /* Register based. */ \ 1563 INSN_3(JMP, JEQ, X), \ 1564 INSN_3(JMP, JNE, X), \ 1565 INSN_3(JMP, JGT, X), \ 1566 INSN_3(JMP, JLT, X), \ 1567 INSN_3(JMP, JGE, X), \ 1568 INSN_3(JMP, JLE, X), \ 1569 INSN_3(JMP, JSGT, X), \ 1570 INSN_3(JMP, JSLT, X), \ 1571 INSN_3(JMP, JSGE, X), \ 1572 INSN_3(JMP, JSLE, X), \ 1573 INSN_3(JMP, JSET, X), \ 1574 /* Immediate based. */ \ 1575 INSN_3(JMP, JEQ, K), \ 1576 INSN_3(JMP, JNE, K), \ 1577 INSN_3(JMP, JGT, K), \ 1578 INSN_3(JMP, JLT, K), \ 1579 INSN_3(JMP, JGE, K), \ 1580 INSN_3(JMP, JLE, K), \ 1581 INSN_3(JMP, JSGT, K), \ 1582 INSN_3(JMP, JSLT, K), \ 1583 INSN_3(JMP, JSGE, K), \ 1584 INSN_3(JMP, JSLE, K), \ 1585 INSN_3(JMP, JSET, K), \ 1586 INSN_2(JMP, JA), \ 1587 /* Store instructions. */ \ 1588 /* Register based. */ \ 1589 INSN_3(STX, MEM, B), \ 1590 INSN_3(STX, MEM, H), \ 1591 INSN_3(STX, MEM, W), \ 1592 INSN_3(STX, MEM, DW), \ 1593 INSN_3(STX, ATOMIC, W), \ 1594 INSN_3(STX, ATOMIC, DW), \ 1595 /* Immediate based. */ \ 1596 INSN_3(ST, MEM, B), \ 1597 INSN_3(ST, MEM, H), \ 1598 INSN_3(ST, MEM, W), \ 1599 INSN_3(ST, MEM, DW), \ 1600 /* Load instructions. */ \ 1601 /* Register based. */ \ 1602 INSN_3(LDX, MEM, B), \ 1603 INSN_3(LDX, MEM, H), \ 1604 INSN_3(LDX, MEM, W), \ 1605 INSN_3(LDX, MEM, DW), \ 1606 /* Immediate based. */ \ 1607 INSN_3(LD, IMM, DW) 1608 1609 bool bpf_opcode_in_insntable(u8 code) 1610 { 1611 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1612 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1613 static const bool public_insntable[256] = { 1614 [0 ... 255] = false, 1615 /* Now overwrite non-defaults ... */ 1616 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1617 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1618 [BPF_LD | BPF_ABS | BPF_B] = true, 1619 [BPF_LD | BPF_ABS | BPF_H] = true, 1620 [BPF_LD | BPF_ABS | BPF_W] = true, 1621 [BPF_LD | BPF_IND | BPF_B] = true, 1622 [BPF_LD | BPF_IND | BPF_H] = true, 1623 [BPF_LD | BPF_IND | BPF_W] = true, 1624 }; 1625 #undef BPF_INSN_3_TBL 1626 #undef BPF_INSN_2_TBL 1627 return public_insntable[code]; 1628 } 1629 1630 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1631 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1632 { 1633 memset(dst, 0, size); 1634 return -EFAULT; 1635 } 1636 1637 /** 1638 * ___bpf_prog_run - run eBPF program on a given context 1639 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1640 * @insn: is the array of eBPF instructions 1641 * 1642 * Decode and execute eBPF instructions. 1643 * 1644 * Return: whatever value is in %BPF_R0 at program exit 1645 */ 1646 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1647 { 1648 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1649 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1650 static const void * const jumptable[256] __annotate_jump_table = { 1651 [0 ... 255] = &&default_label, 1652 /* Now overwrite non-defaults ... */ 1653 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1654 /* Non-UAPI available opcodes. */ 1655 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1656 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1657 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1658 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1659 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1660 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1661 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1662 }; 1663 #undef BPF_INSN_3_LBL 1664 #undef BPF_INSN_2_LBL 1665 u32 tail_call_cnt = 0; 1666 1667 #define CONT ({ insn++; goto select_insn; }) 1668 #define CONT_JMP ({ insn++; goto select_insn; }) 1669 1670 select_insn: 1671 goto *jumptable[insn->code]; 1672 1673 /* Explicitly mask the register-based shift amounts with 63 or 31 1674 * to avoid undefined behavior. Normally this won't affect the 1675 * generated code, for example, in case of native 64 bit archs such 1676 * as x86-64 or arm64, the compiler is optimizing the AND away for 1677 * the interpreter. In case of JITs, each of the JIT backends compiles 1678 * the BPF shift operations to machine instructions which produce 1679 * implementation-defined results in such a case; the resulting 1680 * contents of the register may be arbitrary, but program behaviour 1681 * as a whole remains defined. In other words, in case of JIT backends, 1682 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1683 */ 1684 /* ALU (shifts) */ 1685 #define SHT(OPCODE, OP) \ 1686 ALU64_##OPCODE##_X: \ 1687 DST = DST OP (SRC & 63); \ 1688 CONT; \ 1689 ALU_##OPCODE##_X: \ 1690 DST = (u32) DST OP ((u32) SRC & 31); \ 1691 CONT; \ 1692 ALU64_##OPCODE##_K: \ 1693 DST = DST OP IMM; \ 1694 CONT; \ 1695 ALU_##OPCODE##_K: \ 1696 DST = (u32) DST OP (u32) IMM; \ 1697 CONT; 1698 /* ALU (rest) */ 1699 #define ALU(OPCODE, OP) \ 1700 ALU64_##OPCODE##_X: \ 1701 DST = DST OP SRC; \ 1702 CONT; \ 1703 ALU_##OPCODE##_X: \ 1704 DST = (u32) DST OP (u32) SRC; \ 1705 CONT; \ 1706 ALU64_##OPCODE##_K: \ 1707 DST = DST OP IMM; \ 1708 CONT; \ 1709 ALU_##OPCODE##_K: \ 1710 DST = (u32) DST OP (u32) IMM; \ 1711 CONT; 1712 ALU(ADD, +) 1713 ALU(SUB, -) 1714 ALU(AND, &) 1715 ALU(OR, |) 1716 ALU(XOR, ^) 1717 ALU(MUL, *) 1718 SHT(LSH, <<) 1719 SHT(RSH, >>) 1720 #undef SHT 1721 #undef ALU 1722 ALU_NEG: 1723 DST = (u32) -DST; 1724 CONT; 1725 ALU64_NEG: 1726 DST = -DST; 1727 CONT; 1728 ALU_MOV_X: 1729 DST = (u32) SRC; 1730 CONT; 1731 ALU_MOV_K: 1732 DST = (u32) IMM; 1733 CONT; 1734 ALU64_MOV_X: 1735 DST = SRC; 1736 CONT; 1737 ALU64_MOV_K: 1738 DST = IMM; 1739 CONT; 1740 LD_IMM_DW: 1741 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1742 insn++; 1743 CONT; 1744 ALU_ARSH_X: 1745 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1746 CONT; 1747 ALU_ARSH_K: 1748 DST = (u64) (u32) (((s32) DST) >> IMM); 1749 CONT; 1750 ALU64_ARSH_X: 1751 (*(s64 *) &DST) >>= (SRC & 63); 1752 CONT; 1753 ALU64_ARSH_K: 1754 (*(s64 *) &DST) >>= IMM; 1755 CONT; 1756 ALU64_MOD_X: 1757 div64_u64_rem(DST, SRC, &AX); 1758 DST = AX; 1759 CONT; 1760 ALU_MOD_X: 1761 AX = (u32) DST; 1762 DST = do_div(AX, (u32) SRC); 1763 CONT; 1764 ALU64_MOD_K: 1765 div64_u64_rem(DST, IMM, &AX); 1766 DST = AX; 1767 CONT; 1768 ALU_MOD_K: 1769 AX = (u32) DST; 1770 DST = do_div(AX, (u32) IMM); 1771 CONT; 1772 ALU64_DIV_X: 1773 DST = div64_u64(DST, SRC); 1774 CONT; 1775 ALU_DIV_X: 1776 AX = (u32) DST; 1777 do_div(AX, (u32) SRC); 1778 DST = (u32) AX; 1779 CONT; 1780 ALU64_DIV_K: 1781 DST = div64_u64(DST, IMM); 1782 CONT; 1783 ALU_DIV_K: 1784 AX = (u32) DST; 1785 do_div(AX, (u32) IMM); 1786 DST = (u32) AX; 1787 CONT; 1788 ALU_END_TO_BE: 1789 switch (IMM) { 1790 case 16: 1791 DST = (__force u16) cpu_to_be16(DST); 1792 break; 1793 case 32: 1794 DST = (__force u32) cpu_to_be32(DST); 1795 break; 1796 case 64: 1797 DST = (__force u64) cpu_to_be64(DST); 1798 break; 1799 } 1800 CONT; 1801 ALU_END_TO_LE: 1802 switch (IMM) { 1803 case 16: 1804 DST = (__force u16) cpu_to_le16(DST); 1805 break; 1806 case 32: 1807 DST = (__force u32) cpu_to_le32(DST); 1808 break; 1809 case 64: 1810 DST = (__force u64) cpu_to_le64(DST); 1811 break; 1812 } 1813 CONT; 1814 1815 /* CALL */ 1816 JMP_CALL: 1817 /* Function call scratches BPF_R1-BPF_R5 registers, 1818 * preserves BPF_R6-BPF_R9, and stores return value 1819 * into BPF_R0. 1820 */ 1821 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1822 BPF_R4, BPF_R5); 1823 CONT; 1824 1825 JMP_CALL_ARGS: 1826 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1827 BPF_R3, BPF_R4, 1828 BPF_R5, 1829 insn + insn->off + 1); 1830 CONT; 1831 1832 JMP_TAIL_CALL: { 1833 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1834 struct bpf_array *array = container_of(map, struct bpf_array, map); 1835 struct bpf_prog *prog; 1836 u32 index = BPF_R3; 1837 1838 if (unlikely(index >= array->map.max_entries)) 1839 goto out; 1840 1841 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 1842 goto out; 1843 1844 tail_call_cnt++; 1845 1846 prog = READ_ONCE(array->ptrs[index]); 1847 if (!prog) 1848 goto out; 1849 1850 /* ARG1 at this point is guaranteed to point to CTX from 1851 * the verifier side due to the fact that the tail call is 1852 * handled like a helper, that is, bpf_tail_call_proto, 1853 * where arg1_type is ARG_PTR_TO_CTX. 1854 */ 1855 insn = prog->insnsi; 1856 goto select_insn; 1857 out: 1858 CONT; 1859 } 1860 JMP_JA: 1861 insn += insn->off; 1862 CONT; 1863 JMP_EXIT: 1864 return BPF_R0; 1865 /* JMP */ 1866 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1867 JMP_##OPCODE##_X: \ 1868 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1869 insn += insn->off; \ 1870 CONT_JMP; \ 1871 } \ 1872 CONT; \ 1873 JMP32_##OPCODE##_X: \ 1874 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1875 insn += insn->off; \ 1876 CONT_JMP; \ 1877 } \ 1878 CONT; \ 1879 JMP_##OPCODE##_K: \ 1880 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1881 insn += insn->off; \ 1882 CONT_JMP; \ 1883 } \ 1884 CONT; \ 1885 JMP32_##OPCODE##_K: \ 1886 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1887 insn += insn->off; \ 1888 CONT_JMP; \ 1889 } \ 1890 CONT; 1891 COND_JMP(u, JEQ, ==) 1892 COND_JMP(u, JNE, !=) 1893 COND_JMP(u, JGT, >) 1894 COND_JMP(u, JLT, <) 1895 COND_JMP(u, JGE, >=) 1896 COND_JMP(u, JLE, <=) 1897 COND_JMP(u, JSET, &) 1898 COND_JMP(s, JSGT, >) 1899 COND_JMP(s, JSLT, <) 1900 COND_JMP(s, JSGE, >=) 1901 COND_JMP(s, JSLE, <=) 1902 #undef COND_JMP 1903 /* ST, STX and LDX*/ 1904 ST_NOSPEC: 1905 /* Speculation barrier for mitigating Speculative Store Bypass. 1906 * In case of arm64, we rely on the firmware mitigation as 1907 * controlled via the ssbd kernel parameter. Whenever the 1908 * mitigation is enabled, it works for all of the kernel code 1909 * with no need to provide any additional instructions here. 1910 * In case of x86, we use 'lfence' insn for mitigation. We 1911 * reuse preexisting logic from Spectre v1 mitigation that 1912 * happens to produce the required code on x86 for v4 as well. 1913 */ 1914 #ifdef CONFIG_X86 1915 barrier_nospec(); 1916 #endif 1917 CONT; 1918 #define LDST(SIZEOP, SIZE) \ 1919 STX_MEM_##SIZEOP: \ 1920 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1921 CONT; \ 1922 ST_MEM_##SIZEOP: \ 1923 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1924 CONT; \ 1925 LDX_MEM_##SIZEOP: \ 1926 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1927 CONT; \ 1928 LDX_PROBE_MEM_##SIZEOP: \ 1929 bpf_probe_read_kernel(&DST, sizeof(SIZE), \ 1930 (const void *)(long) (SRC + insn->off)); \ 1931 DST = *((SIZE *)&DST); \ 1932 CONT; 1933 1934 LDST(B, u8) 1935 LDST(H, u16) 1936 LDST(W, u32) 1937 LDST(DW, u64) 1938 #undef LDST 1939 1940 #define ATOMIC_ALU_OP(BOP, KOP) \ 1941 case BOP: \ 1942 if (BPF_SIZE(insn->code) == BPF_W) \ 1943 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 1944 (DST + insn->off)); \ 1945 else \ 1946 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 1947 (DST + insn->off)); \ 1948 break; \ 1949 case BOP | BPF_FETCH: \ 1950 if (BPF_SIZE(insn->code) == BPF_W) \ 1951 SRC = (u32) atomic_fetch_##KOP( \ 1952 (u32) SRC, \ 1953 (atomic_t *)(unsigned long) (DST + insn->off)); \ 1954 else \ 1955 SRC = (u64) atomic64_fetch_##KOP( \ 1956 (u64) SRC, \ 1957 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 1958 break; 1959 1960 STX_ATOMIC_DW: 1961 STX_ATOMIC_W: 1962 switch (IMM) { 1963 ATOMIC_ALU_OP(BPF_ADD, add) 1964 ATOMIC_ALU_OP(BPF_AND, and) 1965 ATOMIC_ALU_OP(BPF_OR, or) 1966 ATOMIC_ALU_OP(BPF_XOR, xor) 1967 #undef ATOMIC_ALU_OP 1968 1969 case BPF_XCHG: 1970 if (BPF_SIZE(insn->code) == BPF_W) 1971 SRC = (u32) atomic_xchg( 1972 (atomic_t *)(unsigned long) (DST + insn->off), 1973 (u32) SRC); 1974 else 1975 SRC = (u64) atomic64_xchg( 1976 (atomic64_t *)(unsigned long) (DST + insn->off), 1977 (u64) SRC); 1978 break; 1979 case BPF_CMPXCHG: 1980 if (BPF_SIZE(insn->code) == BPF_W) 1981 BPF_R0 = (u32) atomic_cmpxchg( 1982 (atomic_t *)(unsigned long) (DST + insn->off), 1983 (u32) BPF_R0, (u32) SRC); 1984 else 1985 BPF_R0 = (u64) atomic64_cmpxchg( 1986 (atomic64_t *)(unsigned long) (DST + insn->off), 1987 (u64) BPF_R0, (u64) SRC); 1988 break; 1989 1990 default: 1991 goto default_label; 1992 } 1993 CONT; 1994 1995 default_label: 1996 /* If we ever reach this, we have a bug somewhere. Die hard here 1997 * instead of just returning 0; we could be somewhere in a subprog, 1998 * so execution could continue otherwise which we do /not/ want. 1999 * 2000 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 2001 */ 2002 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2003 insn->code, insn->imm); 2004 BUG_ON(1); 2005 return 0; 2006 } 2007 2008 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2009 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2010 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2011 { \ 2012 u64 stack[stack_size / sizeof(u64)]; \ 2013 u64 regs[MAX_BPF_EXT_REG] = {}; \ 2014 \ 2015 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2016 ARG1 = (u64) (unsigned long) ctx; \ 2017 return ___bpf_prog_run(regs, insn); \ 2018 } 2019 2020 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2021 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2022 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2023 const struct bpf_insn *insn) \ 2024 { \ 2025 u64 stack[stack_size / sizeof(u64)]; \ 2026 u64 regs[MAX_BPF_EXT_REG]; \ 2027 \ 2028 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2029 BPF_R1 = r1; \ 2030 BPF_R2 = r2; \ 2031 BPF_R3 = r3; \ 2032 BPF_R4 = r4; \ 2033 BPF_R5 = r5; \ 2034 return ___bpf_prog_run(regs, insn); \ 2035 } 2036 2037 #define EVAL1(FN, X) FN(X) 2038 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2039 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2040 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2041 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2042 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2043 2044 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2045 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2046 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2047 2048 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2049 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2050 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2051 2052 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2053 2054 static unsigned int (*interpreters[])(const void *ctx, 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 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2062 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2063 const struct bpf_insn *insn) = { 2064 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2065 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2066 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2067 }; 2068 #undef PROG_NAME_LIST 2069 2070 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2071 { 2072 stack_depth = max_t(u32, stack_depth, 1); 2073 insn->off = (s16) insn->imm; 2074 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2075 __bpf_call_base_args; 2076 insn->code = BPF_JMP | BPF_CALL_ARGS; 2077 } 2078 2079 #else 2080 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2081 const struct bpf_insn *insn) 2082 { 2083 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2084 * is not working properly, so warn about it! 2085 */ 2086 WARN_ON_ONCE(1); 2087 return 0; 2088 } 2089 #endif 2090 2091 bool bpf_prog_map_compatible(struct bpf_map *map, 2092 const struct bpf_prog *fp) 2093 { 2094 enum bpf_prog_type prog_type = resolve_prog_type(fp); 2095 bool ret; 2096 2097 if (fp->kprobe_override) 2098 return false; 2099 2100 /* XDP programs inserted into maps are not guaranteed to run on 2101 * a particular netdev (and can run outside driver context entirely 2102 * in the case of devmap and cpumap). Until device checks 2103 * are implemented, prohibit adding dev-bound programs to program maps. 2104 */ 2105 if (bpf_prog_is_dev_bound(fp->aux)) 2106 return false; 2107 2108 spin_lock(&map->owner.lock); 2109 if (!map->owner.type) { 2110 /* There's no owner yet where we could check for 2111 * compatibility. 2112 */ 2113 map->owner.type = prog_type; 2114 map->owner.jited = fp->jited; 2115 map->owner.xdp_has_frags = fp->aux->xdp_has_frags; 2116 ret = true; 2117 } else { 2118 ret = map->owner.type == prog_type && 2119 map->owner.jited == fp->jited && 2120 map->owner.xdp_has_frags == fp->aux->xdp_has_frags; 2121 } 2122 spin_unlock(&map->owner.lock); 2123 2124 return ret; 2125 } 2126 2127 static int bpf_check_tail_call(const struct bpf_prog *fp) 2128 { 2129 struct bpf_prog_aux *aux = fp->aux; 2130 int i, ret = 0; 2131 2132 mutex_lock(&aux->used_maps_mutex); 2133 for (i = 0; i < aux->used_map_cnt; i++) { 2134 struct bpf_map *map = aux->used_maps[i]; 2135 2136 if (!map_type_contains_progs(map)) 2137 continue; 2138 2139 if (!bpf_prog_map_compatible(map, fp)) { 2140 ret = -EINVAL; 2141 goto out; 2142 } 2143 } 2144 2145 out: 2146 mutex_unlock(&aux->used_maps_mutex); 2147 return ret; 2148 } 2149 2150 static void bpf_prog_select_func(struct bpf_prog *fp) 2151 { 2152 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2153 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2154 2155 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 2156 #else 2157 fp->bpf_func = __bpf_prog_ret0_warn; 2158 #endif 2159 } 2160 2161 /** 2162 * bpf_prog_select_runtime - select exec runtime for BPF program 2163 * @fp: bpf_prog populated with BPF program 2164 * @err: pointer to error variable 2165 * 2166 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2167 * The BPF program will be executed via bpf_prog_run() function. 2168 * 2169 * Return: the &fp argument along with &err set to 0 for success or 2170 * a negative errno code on failure 2171 */ 2172 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2173 { 2174 /* In case of BPF to BPF calls, verifier did all the prep 2175 * work with regards to JITing, etc. 2176 */ 2177 bool jit_needed = false; 2178 2179 if (fp->bpf_func) 2180 goto finalize; 2181 2182 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2183 bpf_prog_has_kfunc_call(fp)) 2184 jit_needed = true; 2185 2186 bpf_prog_select_func(fp); 2187 2188 /* eBPF JITs can rewrite the program in case constant 2189 * blinding is active. However, in case of error during 2190 * blinding, bpf_int_jit_compile() must always return a 2191 * valid program, which in this case would simply not 2192 * be JITed, but falls back to the interpreter. 2193 */ 2194 if (!bpf_prog_is_offloaded(fp->aux)) { 2195 *err = bpf_prog_alloc_jited_linfo(fp); 2196 if (*err) 2197 return fp; 2198 2199 fp = bpf_int_jit_compile(fp); 2200 bpf_prog_jit_attempt_done(fp); 2201 if (!fp->jited && jit_needed) { 2202 *err = -ENOTSUPP; 2203 return fp; 2204 } 2205 } else { 2206 *err = bpf_prog_offload_compile(fp); 2207 if (*err) 2208 return fp; 2209 } 2210 2211 finalize: 2212 bpf_prog_lock_ro(fp); 2213 2214 /* The tail call compatibility check can only be done at 2215 * this late stage as we need to determine, if we deal 2216 * with JITed or non JITed program concatenations and not 2217 * all eBPF JITs might immediately support all features. 2218 */ 2219 *err = bpf_check_tail_call(fp); 2220 2221 return fp; 2222 } 2223 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2224 2225 static unsigned int __bpf_prog_ret1(const void *ctx, 2226 const struct bpf_insn *insn) 2227 { 2228 return 1; 2229 } 2230 2231 static struct bpf_prog_dummy { 2232 struct bpf_prog prog; 2233 } dummy_bpf_prog = { 2234 .prog = { 2235 .bpf_func = __bpf_prog_ret1, 2236 }, 2237 }; 2238 2239 struct bpf_empty_prog_array bpf_empty_prog_array = { 2240 .null_prog = NULL, 2241 }; 2242 EXPORT_SYMBOL(bpf_empty_prog_array); 2243 2244 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2245 { 2246 if (prog_cnt) 2247 return kzalloc(sizeof(struct bpf_prog_array) + 2248 sizeof(struct bpf_prog_array_item) * 2249 (prog_cnt + 1), 2250 flags); 2251 2252 return &bpf_empty_prog_array.hdr; 2253 } 2254 2255 void bpf_prog_array_free(struct bpf_prog_array *progs) 2256 { 2257 if (!progs || progs == &bpf_empty_prog_array.hdr) 2258 return; 2259 kfree_rcu(progs, rcu); 2260 } 2261 2262 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2263 { 2264 struct bpf_prog_array *progs; 2265 2266 /* If RCU Tasks Trace grace period implies RCU grace period, there is 2267 * no need to call kfree_rcu(), just call kfree() directly. 2268 */ 2269 progs = container_of(rcu, struct bpf_prog_array, rcu); 2270 if (rcu_trace_implies_rcu_gp()) 2271 kfree(progs); 2272 else 2273 kfree_rcu(progs, rcu); 2274 } 2275 2276 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2277 { 2278 if (!progs || progs == &bpf_empty_prog_array.hdr) 2279 return; 2280 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2281 } 2282 2283 int bpf_prog_array_length(struct bpf_prog_array *array) 2284 { 2285 struct bpf_prog_array_item *item; 2286 u32 cnt = 0; 2287 2288 for (item = array->items; item->prog; item++) 2289 if (item->prog != &dummy_bpf_prog.prog) 2290 cnt++; 2291 return cnt; 2292 } 2293 2294 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2295 { 2296 struct bpf_prog_array_item *item; 2297 2298 for (item = array->items; item->prog; item++) 2299 if (item->prog != &dummy_bpf_prog.prog) 2300 return false; 2301 return true; 2302 } 2303 2304 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2305 u32 *prog_ids, 2306 u32 request_cnt) 2307 { 2308 struct bpf_prog_array_item *item; 2309 int i = 0; 2310 2311 for (item = array->items; item->prog; item++) { 2312 if (item->prog == &dummy_bpf_prog.prog) 2313 continue; 2314 prog_ids[i] = item->prog->aux->id; 2315 if (++i == request_cnt) { 2316 item++; 2317 break; 2318 } 2319 } 2320 2321 return !!(item->prog); 2322 } 2323 2324 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2325 __u32 __user *prog_ids, u32 cnt) 2326 { 2327 unsigned long err = 0; 2328 bool nospc; 2329 u32 *ids; 2330 2331 /* users of this function are doing: 2332 * cnt = bpf_prog_array_length(); 2333 * if (cnt > 0) 2334 * bpf_prog_array_copy_to_user(..., cnt); 2335 * so below kcalloc doesn't need extra cnt > 0 check. 2336 */ 2337 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2338 if (!ids) 2339 return -ENOMEM; 2340 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2341 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2342 kfree(ids); 2343 if (err) 2344 return -EFAULT; 2345 if (nospc) 2346 return -ENOSPC; 2347 return 0; 2348 } 2349 2350 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2351 struct bpf_prog *old_prog) 2352 { 2353 struct bpf_prog_array_item *item; 2354 2355 for (item = array->items; item->prog; item++) 2356 if (item->prog == old_prog) { 2357 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2358 break; 2359 } 2360 } 2361 2362 /** 2363 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2364 * index into the program array with 2365 * a dummy no-op program. 2366 * @array: a bpf_prog_array 2367 * @index: the index of the program to replace 2368 * 2369 * Skips over dummy programs, by not counting them, when calculating 2370 * the position of the program to replace. 2371 * 2372 * Return: 2373 * * 0 - Success 2374 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2375 * * -ENOENT - Index out of range 2376 */ 2377 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2378 { 2379 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2380 } 2381 2382 /** 2383 * bpf_prog_array_update_at() - Updates the program at the given index 2384 * into the program array. 2385 * @array: a bpf_prog_array 2386 * @index: the index of the program to update 2387 * @prog: the program to insert into the array 2388 * 2389 * Skips over dummy programs, by not counting them, when calculating 2390 * the position of the program to update. 2391 * 2392 * Return: 2393 * * 0 - Success 2394 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2395 * * -ENOENT - Index out of range 2396 */ 2397 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2398 struct bpf_prog *prog) 2399 { 2400 struct bpf_prog_array_item *item; 2401 2402 if (unlikely(index < 0)) 2403 return -EINVAL; 2404 2405 for (item = array->items; item->prog; item++) { 2406 if (item->prog == &dummy_bpf_prog.prog) 2407 continue; 2408 if (!index) { 2409 WRITE_ONCE(item->prog, prog); 2410 return 0; 2411 } 2412 index--; 2413 } 2414 return -ENOENT; 2415 } 2416 2417 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2418 struct bpf_prog *exclude_prog, 2419 struct bpf_prog *include_prog, 2420 u64 bpf_cookie, 2421 struct bpf_prog_array **new_array) 2422 { 2423 int new_prog_cnt, carry_prog_cnt = 0; 2424 struct bpf_prog_array_item *existing, *new; 2425 struct bpf_prog_array *array; 2426 bool found_exclude = false; 2427 2428 /* Figure out how many existing progs we need to carry over to 2429 * the new array. 2430 */ 2431 if (old_array) { 2432 existing = old_array->items; 2433 for (; existing->prog; existing++) { 2434 if (existing->prog == exclude_prog) { 2435 found_exclude = true; 2436 continue; 2437 } 2438 if (existing->prog != &dummy_bpf_prog.prog) 2439 carry_prog_cnt++; 2440 if (existing->prog == include_prog) 2441 return -EEXIST; 2442 } 2443 } 2444 2445 if (exclude_prog && !found_exclude) 2446 return -ENOENT; 2447 2448 /* How many progs (not NULL) will be in the new array? */ 2449 new_prog_cnt = carry_prog_cnt; 2450 if (include_prog) 2451 new_prog_cnt += 1; 2452 2453 /* Do we have any prog (not NULL) in the new array? */ 2454 if (!new_prog_cnt) { 2455 *new_array = NULL; 2456 return 0; 2457 } 2458 2459 /* +1 as the end of prog_array is marked with NULL */ 2460 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2461 if (!array) 2462 return -ENOMEM; 2463 new = array->items; 2464 2465 /* Fill in the new prog array */ 2466 if (carry_prog_cnt) { 2467 existing = old_array->items; 2468 for (; existing->prog; existing++) { 2469 if (existing->prog == exclude_prog || 2470 existing->prog == &dummy_bpf_prog.prog) 2471 continue; 2472 2473 new->prog = existing->prog; 2474 new->bpf_cookie = existing->bpf_cookie; 2475 new++; 2476 } 2477 } 2478 if (include_prog) { 2479 new->prog = include_prog; 2480 new->bpf_cookie = bpf_cookie; 2481 new++; 2482 } 2483 new->prog = NULL; 2484 *new_array = array; 2485 return 0; 2486 } 2487 2488 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2489 u32 *prog_ids, u32 request_cnt, 2490 u32 *prog_cnt) 2491 { 2492 u32 cnt = 0; 2493 2494 if (array) 2495 cnt = bpf_prog_array_length(array); 2496 2497 *prog_cnt = cnt; 2498 2499 /* return early if user requested only program count or nothing to copy */ 2500 if (!request_cnt || !cnt) 2501 return 0; 2502 2503 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2504 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2505 : 0; 2506 } 2507 2508 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2509 struct bpf_map **used_maps, u32 len) 2510 { 2511 struct bpf_map *map; 2512 u32 i; 2513 2514 for (i = 0; i < len; i++) { 2515 map = used_maps[i]; 2516 if (map->ops->map_poke_untrack) 2517 map->ops->map_poke_untrack(map, aux); 2518 bpf_map_put(map); 2519 } 2520 } 2521 2522 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2523 { 2524 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2525 kfree(aux->used_maps); 2526 } 2527 2528 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2529 struct btf_mod_pair *used_btfs, u32 len) 2530 { 2531 #ifdef CONFIG_BPF_SYSCALL 2532 struct btf_mod_pair *btf_mod; 2533 u32 i; 2534 2535 for (i = 0; i < len; i++) { 2536 btf_mod = &used_btfs[i]; 2537 if (btf_mod->module) 2538 module_put(btf_mod->module); 2539 btf_put(btf_mod->btf); 2540 } 2541 #endif 2542 } 2543 2544 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2545 { 2546 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2547 kfree(aux->used_btfs); 2548 } 2549 2550 static void bpf_prog_free_deferred(struct work_struct *work) 2551 { 2552 struct bpf_prog_aux *aux; 2553 int i; 2554 2555 aux = container_of(work, struct bpf_prog_aux, work); 2556 #ifdef CONFIG_BPF_SYSCALL 2557 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2558 #endif 2559 #ifdef CONFIG_CGROUP_BPF 2560 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2561 bpf_cgroup_atype_put(aux->cgroup_atype); 2562 #endif 2563 bpf_free_used_maps(aux); 2564 bpf_free_used_btfs(aux); 2565 if (bpf_prog_is_dev_bound(aux)) 2566 bpf_prog_dev_bound_destroy(aux->prog); 2567 #ifdef CONFIG_PERF_EVENTS 2568 if (aux->prog->has_callchain_buf) 2569 put_callchain_buffers(); 2570 #endif 2571 if (aux->dst_trampoline) 2572 bpf_trampoline_put(aux->dst_trampoline); 2573 for (i = 0; i < aux->func_cnt; i++) { 2574 /* We can just unlink the subprog poke descriptor table as 2575 * it was originally linked to the main program and is also 2576 * released along with it. 2577 */ 2578 aux->func[i]->aux->poke_tab = NULL; 2579 bpf_jit_free(aux->func[i]); 2580 } 2581 if (aux->func_cnt) { 2582 kfree(aux->func); 2583 bpf_prog_unlock_free(aux->prog); 2584 } else { 2585 bpf_jit_free(aux->prog); 2586 } 2587 } 2588 2589 void bpf_prog_free(struct bpf_prog *fp) 2590 { 2591 struct bpf_prog_aux *aux = fp->aux; 2592 2593 if (aux->dst_prog) 2594 bpf_prog_put(aux->dst_prog); 2595 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2596 schedule_work(&aux->work); 2597 } 2598 EXPORT_SYMBOL_GPL(bpf_prog_free); 2599 2600 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2601 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2602 2603 void bpf_user_rnd_init_once(void) 2604 { 2605 prandom_init_once(&bpf_user_rnd_state); 2606 } 2607 2608 BPF_CALL_0(bpf_user_rnd_u32) 2609 { 2610 /* Should someone ever have the rather unwise idea to use some 2611 * of the registers passed into this function, then note that 2612 * this function is called from native eBPF and classic-to-eBPF 2613 * transformations. Register assignments from both sides are 2614 * different, f.e. classic always sets fn(ctx, A, X) here. 2615 */ 2616 struct rnd_state *state; 2617 u32 res; 2618 2619 state = &get_cpu_var(bpf_user_rnd_state); 2620 res = prandom_u32_state(state); 2621 put_cpu_var(bpf_user_rnd_state); 2622 2623 return res; 2624 } 2625 2626 BPF_CALL_0(bpf_get_raw_cpu_id) 2627 { 2628 return raw_smp_processor_id(); 2629 } 2630 2631 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2632 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2633 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2634 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2635 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2636 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2637 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2638 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2639 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2640 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2641 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2642 2643 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2644 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2645 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2646 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2647 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2648 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2649 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak; 2650 2651 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2652 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2653 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2654 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2655 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2656 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2657 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2658 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2659 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2660 const struct bpf_func_proto bpf_set_retval_proto __weak; 2661 const struct bpf_func_proto bpf_get_retval_proto __weak; 2662 2663 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2664 { 2665 return NULL; 2666 } 2667 2668 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2669 { 2670 return NULL; 2671 } 2672 2673 u64 __weak 2674 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2675 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2676 { 2677 return -ENOTSUPP; 2678 } 2679 EXPORT_SYMBOL_GPL(bpf_event_output); 2680 2681 /* Always built-in helper functions. */ 2682 const struct bpf_func_proto bpf_tail_call_proto = { 2683 .func = NULL, 2684 .gpl_only = false, 2685 .ret_type = RET_VOID, 2686 .arg1_type = ARG_PTR_TO_CTX, 2687 .arg2_type = ARG_CONST_MAP_PTR, 2688 .arg3_type = ARG_ANYTHING, 2689 }; 2690 2691 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2692 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2693 * eBPF and implicitly also cBPF can get JITed! 2694 */ 2695 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2696 { 2697 return prog; 2698 } 2699 2700 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2701 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2702 */ 2703 void __weak bpf_jit_compile(struct bpf_prog *prog) 2704 { 2705 } 2706 2707 bool __weak bpf_helper_changes_pkt_data(void *func) 2708 { 2709 return false; 2710 } 2711 2712 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2713 * analysis code and wants explicit zero extension inserted by verifier. 2714 * Otherwise, return FALSE. 2715 * 2716 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2717 * you don't override this. JITs that don't want these extra insns can detect 2718 * them using insn_is_zext. 2719 */ 2720 bool __weak bpf_jit_needs_zext(void) 2721 { 2722 return false; 2723 } 2724 2725 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 2726 bool __weak bpf_jit_supports_subprog_tailcalls(void) 2727 { 2728 return false; 2729 } 2730 2731 bool __weak bpf_jit_supports_kfunc_call(void) 2732 { 2733 return false; 2734 } 2735 2736 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2737 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2738 */ 2739 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2740 int len) 2741 { 2742 return -EFAULT; 2743 } 2744 2745 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2746 void *addr1, void *addr2) 2747 { 2748 return -ENOTSUPP; 2749 } 2750 2751 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 2752 { 2753 return ERR_PTR(-ENOTSUPP); 2754 } 2755 2756 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 2757 { 2758 return -ENOTSUPP; 2759 } 2760 2761 #ifdef CONFIG_BPF_SYSCALL 2762 static int __init bpf_global_ma_init(void) 2763 { 2764 int ret; 2765 2766 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); 2767 bpf_global_ma_set = !ret; 2768 return ret; 2769 } 2770 late_initcall(bpf_global_ma_init); 2771 #endif 2772 2773 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2774 EXPORT_SYMBOL(bpf_stats_enabled_key); 2775 2776 /* All definitions of tracepoints related to BPF. */ 2777 #define CREATE_TRACE_POINTS 2778 #include <linux/bpf_trace.h> 2779 2780 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2781 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2782