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/bpf.h> 26 #include <linux/btf.h> 27 #include <linux/objtool.h> 28 #include <linux/overflow.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/nospec.h> 38 #include <linux/bpf_mem_alloc.h> 39 #include <linux/memcontrol.h> 40 #include <linux/execmem.h> 41 42 #include <asm/barrier.h> 43 #include <asm/unaligned.h> 44 45 /* Registers */ 46 #define BPF_R0 regs[BPF_REG_0] 47 #define BPF_R1 regs[BPF_REG_1] 48 #define BPF_R2 regs[BPF_REG_2] 49 #define BPF_R3 regs[BPF_REG_3] 50 #define BPF_R4 regs[BPF_REG_4] 51 #define BPF_R5 regs[BPF_REG_5] 52 #define BPF_R6 regs[BPF_REG_6] 53 #define BPF_R7 regs[BPF_REG_7] 54 #define BPF_R8 regs[BPF_REG_8] 55 #define BPF_R9 regs[BPF_REG_9] 56 #define BPF_R10 regs[BPF_REG_10] 57 58 /* Named registers */ 59 #define DST regs[insn->dst_reg] 60 #define SRC regs[insn->src_reg] 61 #define FP regs[BPF_REG_FP] 62 #define AX regs[BPF_REG_AX] 63 #define ARG1 regs[BPF_REG_ARG1] 64 #define CTX regs[BPF_REG_CTX] 65 #define OFF insn->off 66 #define IMM insn->imm 67 68 struct bpf_mem_alloc bpf_global_ma; 69 bool bpf_global_ma_set; 70 71 /* No hurry in this branch 72 * 73 * Exported for the bpf jit load helper. 74 */ 75 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 76 { 77 u8 *ptr = NULL; 78 79 if (k >= SKF_NET_OFF) { 80 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 81 } else if (k >= SKF_LL_OFF) { 82 if (unlikely(!skb_mac_header_was_set(skb))) 83 return NULL; 84 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 85 } 86 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 87 return ptr; 88 89 return NULL; 90 } 91 92 /* tell bpf programs that include vmlinux.h kernel's PAGE_SIZE */ 93 enum page_size_enum { 94 __PAGE_SIZE = PAGE_SIZE 95 }; 96 97 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 98 { 99 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 100 struct bpf_prog_aux *aux; 101 struct bpf_prog *fp; 102 103 size = round_up(size, __PAGE_SIZE); 104 fp = __vmalloc(size, gfp_flags); 105 if (fp == NULL) 106 return NULL; 107 108 aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 109 if (aux == NULL) { 110 vfree(fp); 111 return NULL; 112 } 113 fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 114 if (!fp->active) { 115 vfree(fp); 116 kfree(aux); 117 return NULL; 118 } 119 120 fp->pages = size / PAGE_SIZE; 121 fp->aux = aux; 122 fp->aux->prog = fp; 123 fp->jit_requested = ebpf_jit_enabled(); 124 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 125 #ifdef CONFIG_CGROUP_BPF 126 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 127 #endif 128 129 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 130 #ifdef CONFIG_FINEIBT 131 INIT_LIST_HEAD_RCU(&fp->aux->ksym_prefix.lnode); 132 #endif 133 mutex_init(&fp->aux->used_maps_mutex); 134 mutex_init(&fp->aux->dst_mutex); 135 136 return fp; 137 } 138 139 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 140 { 141 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 142 struct bpf_prog *prog; 143 int cpu; 144 145 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 146 if (!prog) 147 return NULL; 148 149 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 150 if (!prog->stats) { 151 free_percpu(prog->active); 152 kfree(prog->aux); 153 vfree(prog); 154 return NULL; 155 } 156 157 for_each_possible_cpu(cpu) { 158 struct bpf_prog_stats *pstats; 159 160 pstats = per_cpu_ptr(prog->stats, cpu); 161 u64_stats_init(&pstats->syncp); 162 } 163 return prog; 164 } 165 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 166 167 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 168 { 169 if (!prog->aux->nr_linfo || !prog->jit_requested) 170 return 0; 171 172 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 173 sizeof(*prog->aux->jited_linfo), 174 bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN)); 175 if (!prog->aux->jited_linfo) 176 return -ENOMEM; 177 178 return 0; 179 } 180 181 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 182 { 183 if (prog->aux->jited_linfo && 184 (!prog->jited || !prog->aux->jited_linfo[0])) { 185 kvfree(prog->aux->jited_linfo); 186 prog->aux->jited_linfo = NULL; 187 } 188 189 kfree(prog->aux->kfunc_tab); 190 prog->aux->kfunc_tab = NULL; 191 } 192 193 /* The jit engine is responsible to provide an array 194 * for insn_off to the jited_off mapping (insn_to_jit_off). 195 * 196 * The idx to this array is the insn_off. Hence, the insn_off 197 * here is relative to the prog itself instead of the main prog. 198 * This array has one entry for each xlated bpf insn. 199 * 200 * jited_off is the byte off to the end of the jited insn. 201 * 202 * Hence, with 203 * insn_start: 204 * The first bpf insn off of the prog. The insn off 205 * here is relative to the main prog. 206 * e.g. if prog is a subprog, insn_start > 0 207 * linfo_idx: 208 * The prog's idx to prog->aux->linfo and jited_linfo 209 * 210 * jited_linfo[linfo_idx] = prog->bpf_func 211 * 212 * For i > linfo_idx, 213 * 214 * jited_linfo[i] = prog->bpf_func + 215 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 216 */ 217 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 218 const u32 *insn_to_jit_off) 219 { 220 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 221 const struct bpf_line_info *linfo; 222 void **jited_linfo; 223 224 if (!prog->aux->jited_linfo || prog->aux->func_idx > prog->aux->func_cnt) 225 /* Userspace did not provide linfo */ 226 return; 227 228 linfo_idx = prog->aux->linfo_idx; 229 linfo = &prog->aux->linfo[linfo_idx]; 230 insn_start = linfo[0].insn_off; 231 insn_end = insn_start + prog->len; 232 233 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 234 jited_linfo[0] = prog->bpf_func; 235 236 nr_linfo = prog->aux->nr_linfo - linfo_idx; 237 238 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 239 /* The verifier ensures that linfo[i].insn_off is 240 * strictly increasing 241 */ 242 jited_linfo[i] = prog->bpf_func + 243 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 244 } 245 246 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 247 gfp_t gfp_extra_flags) 248 { 249 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 250 struct bpf_prog *fp; 251 u32 pages; 252 253 size = round_up(size, PAGE_SIZE); 254 pages = size / PAGE_SIZE; 255 if (pages <= fp_old->pages) 256 return fp_old; 257 258 fp = __vmalloc(size, gfp_flags); 259 if (fp) { 260 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 261 fp->pages = pages; 262 fp->aux->prog = fp; 263 264 /* We keep fp->aux from fp_old around in the new 265 * reallocated structure. 266 */ 267 fp_old->aux = NULL; 268 fp_old->stats = NULL; 269 fp_old->active = NULL; 270 __bpf_prog_free(fp_old); 271 } 272 273 return fp; 274 } 275 276 void __bpf_prog_free(struct bpf_prog *fp) 277 { 278 if (fp->aux) { 279 mutex_destroy(&fp->aux->used_maps_mutex); 280 mutex_destroy(&fp->aux->dst_mutex); 281 kfree(fp->aux->poke_tab); 282 kfree(fp->aux); 283 } 284 free_percpu(fp->stats); 285 free_percpu(fp->active); 286 vfree(fp); 287 } 288 289 int bpf_prog_calc_tag(struct bpf_prog *fp) 290 { 291 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 292 u32 raw_size = bpf_prog_tag_scratch_size(fp); 293 u32 digest[SHA1_DIGEST_WORDS]; 294 u32 ws[SHA1_WORKSPACE_WORDS]; 295 u32 i, bsize, psize, blocks; 296 struct bpf_insn *dst; 297 bool was_ld_map; 298 u8 *raw, *todo; 299 __be32 *result; 300 __be64 *bits; 301 302 raw = vmalloc(raw_size); 303 if (!raw) 304 return -ENOMEM; 305 306 sha1_init(digest); 307 memset(ws, 0, sizeof(ws)); 308 309 /* We need to take out the map fd for the digest calculation 310 * since they are unstable from user space side. 311 */ 312 dst = (void *)raw; 313 for (i = 0, was_ld_map = false; i < fp->len; i++) { 314 dst[i] = fp->insnsi[i]; 315 if (!was_ld_map && 316 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 317 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 318 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 319 was_ld_map = true; 320 dst[i].imm = 0; 321 } else if (was_ld_map && 322 dst[i].code == 0 && 323 dst[i].dst_reg == 0 && 324 dst[i].src_reg == 0 && 325 dst[i].off == 0) { 326 was_ld_map = false; 327 dst[i].imm = 0; 328 } else { 329 was_ld_map = false; 330 } 331 } 332 333 psize = bpf_prog_insn_size(fp); 334 memset(&raw[psize], 0, raw_size - psize); 335 raw[psize++] = 0x80; 336 337 bsize = round_up(psize, SHA1_BLOCK_SIZE); 338 blocks = bsize / SHA1_BLOCK_SIZE; 339 todo = raw; 340 if (bsize - psize >= sizeof(__be64)) { 341 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 342 } else { 343 bits = (__be64 *)(todo + bsize + bits_offset); 344 blocks++; 345 } 346 *bits = cpu_to_be64((psize - 1) << 3); 347 348 while (blocks--) { 349 sha1_transform(digest, todo, ws); 350 todo += SHA1_BLOCK_SIZE; 351 } 352 353 result = (__force __be32 *)digest; 354 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 355 result[i] = cpu_to_be32(digest[i]); 356 memcpy(fp->tag, result, sizeof(fp->tag)); 357 358 vfree(raw); 359 return 0; 360 } 361 362 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 363 s32 end_new, s32 curr, const bool probe_pass) 364 { 365 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 366 s32 delta = end_new - end_old; 367 s64 imm = insn->imm; 368 369 if (curr < pos && curr + imm + 1 >= end_old) 370 imm += delta; 371 else if (curr >= end_new && curr + imm + 1 < end_new) 372 imm -= delta; 373 if (imm < imm_min || imm > imm_max) 374 return -ERANGE; 375 if (!probe_pass) 376 insn->imm = imm; 377 return 0; 378 } 379 380 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 381 s32 end_new, s32 curr, const bool probe_pass) 382 { 383 s64 off_min, off_max, off; 384 s32 delta = end_new - end_old; 385 386 if (insn->code == (BPF_JMP32 | BPF_JA)) { 387 off = insn->imm; 388 off_min = S32_MIN; 389 off_max = S32_MAX; 390 } else { 391 off = insn->off; 392 off_min = S16_MIN; 393 off_max = S16_MAX; 394 } 395 396 if (curr < pos && curr + off + 1 >= end_old) 397 off += delta; 398 else if (curr >= end_new && curr + off + 1 < end_new) 399 off -= delta; 400 if (off < off_min || off > off_max) 401 return -ERANGE; 402 if (!probe_pass) { 403 if (insn->code == (BPF_JMP32 | BPF_JA)) 404 insn->imm = off; 405 else 406 insn->off = off; 407 } 408 return 0; 409 } 410 411 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 412 s32 end_new, const bool probe_pass) 413 { 414 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 415 struct bpf_insn *insn = prog->insnsi; 416 int ret = 0; 417 418 for (i = 0; i < insn_cnt; i++, insn++) { 419 u8 code; 420 421 /* In the probing pass we still operate on the original, 422 * unpatched image in order to check overflows before we 423 * do any other adjustments. Therefore skip the patchlet. 424 */ 425 if (probe_pass && i == pos) { 426 i = end_new; 427 insn = prog->insnsi + end_old; 428 } 429 if (bpf_pseudo_func(insn)) { 430 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 431 end_new, i, probe_pass); 432 if (ret) 433 return ret; 434 continue; 435 } 436 code = insn->code; 437 if ((BPF_CLASS(code) != BPF_JMP && 438 BPF_CLASS(code) != BPF_JMP32) || 439 BPF_OP(code) == BPF_EXIT) 440 continue; 441 /* Adjust offset of jmps if we cross patch boundaries. */ 442 if (BPF_OP(code) == BPF_CALL) { 443 if (insn->src_reg != BPF_PSEUDO_CALL) 444 continue; 445 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 446 end_new, i, probe_pass); 447 } else { 448 ret = bpf_adj_delta_to_off(insn, pos, end_old, 449 end_new, i, probe_pass); 450 } 451 if (ret) 452 break; 453 } 454 455 return ret; 456 } 457 458 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 459 { 460 struct bpf_line_info *linfo; 461 u32 i, nr_linfo; 462 463 nr_linfo = prog->aux->nr_linfo; 464 if (!nr_linfo || !delta) 465 return; 466 467 linfo = prog->aux->linfo; 468 469 for (i = 0; i < nr_linfo; i++) 470 if (off < linfo[i].insn_off) 471 break; 472 473 /* Push all off < linfo[i].insn_off by delta */ 474 for (; i < nr_linfo; i++) 475 linfo[i].insn_off += delta; 476 } 477 478 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 479 const struct bpf_insn *patch, u32 len) 480 { 481 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 482 const u32 cnt_max = S16_MAX; 483 struct bpf_prog *prog_adj; 484 int err; 485 486 /* Since our patchlet doesn't expand the image, we're done. */ 487 if (insn_delta == 0) { 488 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 489 return prog; 490 } 491 492 insn_adj_cnt = prog->len + insn_delta; 493 494 /* Reject anything that would potentially let the insn->off 495 * target overflow when we have excessive program expansions. 496 * We need to probe here before we do any reallocation where 497 * we afterwards may not fail anymore. 498 */ 499 if (insn_adj_cnt > cnt_max && 500 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 501 return ERR_PTR(err); 502 503 /* Several new instructions need to be inserted. Make room 504 * for them. Likely, there's no need for a new allocation as 505 * last page could have large enough tailroom. 506 */ 507 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 508 GFP_USER); 509 if (!prog_adj) 510 return ERR_PTR(-ENOMEM); 511 512 prog_adj->len = insn_adj_cnt; 513 514 /* Patching happens in 3 steps: 515 * 516 * 1) Move over tail of insnsi from next instruction onwards, 517 * so we can patch the single target insn with one or more 518 * new ones (patching is always from 1 to n insns, n > 0). 519 * 2) Inject new instructions at the target location. 520 * 3) Adjust branch offsets if necessary. 521 */ 522 insn_rest = insn_adj_cnt - off - len; 523 524 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 525 sizeof(*patch) * insn_rest); 526 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 527 528 /* We are guaranteed to not fail at this point, otherwise 529 * the ship has sailed to reverse to the original state. An 530 * overflow cannot happen at this point. 531 */ 532 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 533 534 bpf_adj_linfo(prog_adj, off, insn_delta); 535 536 return prog_adj; 537 } 538 539 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 540 { 541 /* Branch offsets can't overflow when program is shrinking, no need 542 * to call bpf_adj_branches(..., true) here 543 */ 544 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 545 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 546 prog->len -= cnt; 547 548 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 549 } 550 551 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 552 { 553 int i; 554 555 for (i = 0; i < fp->aux->real_func_cnt; i++) 556 bpf_prog_kallsyms_del(fp->aux->func[i]); 557 } 558 559 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 560 { 561 bpf_prog_kallsyms_del_subprogs(fp); 562 bpf_prog_kallsyms_del(fp); 563 } 564 565 #ifdef CONFIG_BPF_JIT 566 /* All BPF JIT sysctl knobs here. */ 567 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 568 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 569 int bpf_jit_harden __read_mostly; 570 long bpf_jit_limit __read_mostly; 571 long bpf_jit_limit_max __read_mostly; 572 573 static void 574 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 575 { 576 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 577 578 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 579 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 580 } 581 582 static void 583 bpf_prog_ksym_set_name(struct bpf_prog *prog) 584 { 585 char *sym = prog->aux->ksym.name; 586 const char *end = sym + KSYM_NAME_LEN; 587 const struct btf_type *type; 588 const char *func_name; 589 590 BUILD_BUG_ON(sizeof("bpf_prog_") + 591 sizeof(prog->tag) * 2 + 592 /* name has been null terminated. 593 * We should need +1 for the '_' preceding 594 * the name. However, the null character 595 * is double counted between the name and the 596 * sizeof("bpf_prog_") above, so we omit 597 * the +1 here. 598 */ 599 sizeof(prog->aux->name) > KSYM_NAME_LEN); 600 601 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 602 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 603 604 /* prog->aux->name will be ignored if full btf name is available */ 605 if (prog->aux->func_info_cnt && prog->aux->func_idx < prog->aux->func_info_cnt) { 606 type = btf_type_by_id(prog->aux->btf, 607 prog->aux->func_info[prog->aux->func_idx].type_id); 608 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 609 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 610 return; 611 } 612 613 if (prog->aux->name[0]) 614 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 615 else 616 *sym = 0; 617 } 618 619 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 620 { 621 return container_of(n, struct bpf_ksym, tnode)->start; 622 } 623 624 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 625 struct latch_tree_node *b) 626 { 627 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 628 } 629 630 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 631 { 632 unsigned long val = (unsigned long)key; 633 const struct bpf_ksym *ksym; 634 635 ksym = container_of(n, struct bpf_ksym, tnode); 636 637 if (val < ksym->start) 638 return -1; 639 /* Ensure that we detect return addresses as part of the program, when 640 * the final instruction is a call for a program part of the stack 641 * trace. Therefore, do val > ksym->end instead of val >= ksym->end. 642 */ 643 if (val > ksym->end) 644 return 1; 645 646 return 0; 647 } 648 649 static const struct latch_tree_ops bpf_tree_ops = { 650 .less = bpf_tree_less, 651 .comp = bpf_tree_comp, 652 }; 653 654 static DEFINE_SPINLOCK(bpf_lock); 655 static LIST_HEAD(bpf_kallsyms); 656 static struct latch_tree_root bpf_tree __cacheline_aligned; 657 658 void bpf_ksym_add(struct bpf_ksym *ksym) 659 { 660 spin_lock_bh(&bpf_lock); 661 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 662 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 663 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 664 spin_unlock_bh(&bpf_lock); 665 } 666 667 static void __bpf_ksym_del(struct bpf_ksym *ksym) 668 { 669 if (list_empty(&ksym->lnode)) 670 return; 671 672 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 673 list_del_rcu(&ksym->lnode); 674 } 675 676 void bpf_ksym_del(struct bpf_ksym *ksym) 677 { 678 spin_lock_bh(&bpf_lock); 679 __bpf_ksym_del(ksym); 680 spin_unlock_bh(&bpf_lock); 681 } 682 683 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 684 { 685 return fp->jited && !bpf_prog_was_classic(fp); 686 } 687 688 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 689 { 690 if (!bpf_prog_kallsyms_candidate(fp) || 691 !bpf_token_capable(fp->aux->token, CAP_BPF)) 692 return; 693 694 bpf_prog_ksym_set_addr(fp); 695 bpf_prog_ksym_set_name(fp); 696 fp->aux->ksym.prog = true; 697 698 bpf_ksym_add(&fp->aux->ksym); 699 700 #ifdef CONFIG_FINEIBT 701 /* 702 * When FineIBT, code in the __cfi_foo() symbols can get executed 703 * and hence unwinder needs help. 704 */ 705 if (cfi_mode != CFI_FINEIBT) 706 return; 707 708 snprintf(fp->aux->ksym_prefix.name, KSYM_NAME_LEN, 709 "__cfi_%s", fp->aux->ksym.name); 710 711 fp->aux->ksym_prefix.start = (unsigned long) fp->bpf_func - 16; 712 fp->aux->ksym_prefix.end = (unsigned long) fp->bpf_func; 713 714 bpf_ksym_add(&fp->aux->ksym_prefix); 715 #endif 716 } 717 718 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 719 { 720 if (!bpf_prog_kallsyms_candidate(fp)) 721 return; 722 723 bpf_ksym_del(&fp->aux->ksym); 724 #ifdef CONFIG_FINEIBT 725 if (cfi_mode != CFI_FINEIBT) 726 return; 727 bpf_ksym_del(&fp->aux->ksym_prefix); 728 #endif 729 } 730 731 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 732 { 733 struct latch_tree_node *n; 734 735 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 736 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 737 } 738 739 int __bpf_address_lookup(unsigned long addr, unsigned long *size, 740 unsigned long *off, char *sym) 741 { 742 struct bpf_ksym *ksym; 743 int ret = 0; 744 745 rcu_read_lock(); 746 ksym = bpf_ksym_find(addr); 747 if (ksym) { 748 unsigned long symbol_start = ksym->start; 749 unsigned long symbol_end = ksym->end; 750 751 ret = strscpy(sym, ksym->name, KSYM_NAME_LEN); 752 753 if (size) 754 *size = symbol_end - symbol_start; 755 if (off) 756 *off = addr - symbol_start; 757 } 758 rcu_read_unlock(); 759 760 return ret; 761 } 762 763 bool is_bpf_text_address(unsigned long addr) 764 { 765 bool ret; 766 767 rcu_read_lock(); 768 ret = bpf_ksym_find(addr) != NULL; 769 rcu_read_unlock(); 770 771 return ret; 772 } 773 774 struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 775 { 776 struct bpf_ksym *ksym = bpf_ksym_find(addr); 777 778 return ksym && ksym->prog ? 779 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 780 NULL; 781 } 782 783 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 784 { 785 const struct exception_table_entry *e = NULL; 786 struct bpf_prog *prog; 787 788 rcu_read_lock(); 789 prog = bpf_prog_ksym_find(addr); 790 if (!prog) 791 goto out; 792 if (!prog->aux->num_exentries) 793 goto out; 794 795 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 796 out: 797 rcu_read_unlock(); 798 return e; 799 } 800 801 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 802 char *sym) 803 { 804 struct bpf_ksym *ksym; 805 unsigned int it = 0; 806 int ret = -ERANGE; 807 808 if (!bpf_jit_kallsyms_enabled()) 809 return ret; 810 811 rcu_read_lock(); 812 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 813 if (it++ != symnum) 814 continue; 815 816 strscpy(sym, ksym->name, KSYM_NAME_LEN); 817 818 *value = ksym->start; 819 *type = BPF_SYM_ELF_TYPE; 820 821 ret = 0; 822 break; 823 } 824 rcu_read_unlock(); 825 826 return ret; 827 } 828 829 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 830 struct bpf_jit_poke_descriptor *poke) 831 { 832 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 833 static const u32 poke_tab_max = 1024; 834 u32 slot = prog->aux->size_poke_tab; 835 u32 size = slot + 1; 836 837 if (size > poke_tab_max) 838 return -ENOSPC; 839 if (poke->tailcall_target || poke->tailcall_target_stable || 840 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 841 return -EINVAL; 842 843 switch (poke->reason) { 844 case BPF_POKE_REASON_TAIL_CALL: 845 if (!poke->tail_call.map) 846 return -EINVAL; 847 break; 848 default: 849 return -EINVAL; 850 } 851 852 tab = krealloc_array(tab, size, sizeof(*poke), GFP_KERNEL); 853 if (!tab) 854 return -ENOMEM; 855 856 memcpy(&tab[slot], poke, sizeof(*poke)); 857 prog->aux->size_poke_tab = size; 858 prog->aux->poke_tab = tab; 859 860 return slot; 861 } 862 863 /* 864 * BPF program pack allocator. 865 * 866 * Most BPF programs are pretty small. Allocating a hole page for each 867 * program is sometime a waste. Many small bpf program also adds pressure 868 * to instruction TLB. To solve this issue, we introduce a BPF program pack 869 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 870 * to host BPF programs. 871 */ 872 #define BPF_PROG_CHUNK_SHIFT 6 873 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 874 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 875 876 struct bpf_prog_pack { 877 struct list_head list; 878 void *ptr; 879 unsigned long bitmap[]; 880 }; 881 882 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) 883 { 884 memset(area, 0, size); 885 } 886 887 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 888 889 static DEFINE_MUTEX(pack_mutex); 890 static LIST_HEAD(pack_list); 891 892 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 893 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 894 */ 895 #ifdef PMD_SIZE 896 /* PMD_SIZE is really big for some archs. It doesn't make sense to 897 * reserve too much memory in one allocation. Hardcode BPF_PROG_PACK_SIZE to 898 * 2MiB * num_possible_nodes(). On most architectures PMD_SIZE will be 899 * greater than or equal to 2MB. 900 */ 901 #define BPF_PROG_PACK_SIZE (SZ_2M * num_possible_nodes()) 902 #else 903 #define BPF_PROG_PACK_SIZE PAGE_SIZE 904 #endif 905 906 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 907 908 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 909 { 910 struct bpf_prog_pack *pack; 911 int err; 912 913 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), 914 GFP_KERNEL); 915 if (!pack) 916 return NULL; 917 pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE); 918 if (!pack->ptr) 919 goto out; 920 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 921 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 922 923 set_vm_flush_reset_perms(pack->ptr); 924 err = set_memory_rox((unsigned long)pack->ptr, 925 BPF_PROG_PACK_SIZE / PAGE_SIZE); 926 if (err) 927 goto out; 928 list_add_tail(&pack->list, &pack_list); 929 return pack; 930 931 out: 932 bpf_jit_free_exec(pack->ptr); 933 kfree(pack); 934 return NULL; 935 } 936 937 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 938 { 939 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 940 struct bpf_prog_pack *pack; 941 unsigned long pos; 942 void *ptr = NULL; 943 944 mutex_lock(&pack_mutex); 945 if (size > BPF_PROG_PACK_SIZE) { 946 size = round_up(size, PAGE_SIZE); 947 ptr = bpf_jit_alloc_exec(size); 948 if (ptr) { 949 int err; 950 951 bpf_fill_ill_insns(ptr, size); 952 set_vm_flush_reset_perms(ptr); 953 err = set_memory_rox((unsigned long)ptr, 954 size / PAGE_SIZE); 955 if (err) { 956 bpf_jit_free_exec(ptr); 957 ptr = NULL; 958 } 959 } 960 goto out; 961 } 962 list_for_each_entry(pack, &pack_list, list) { 963 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 964 nbits, 0); 965 if (pos < BPF_PROG_CHUNK_COUNT) 966 goto found_free_area; 967 } 968 969 pack = alloc_new_pack(bpf_fill_ill_insns); 970 if (!pack) 971 goto out; 972 973 pos = 0; 974 975 found_free_area: 976 bitmap_set(pack->bitmap, pos, nbits); 977 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 978 979 out: 980 mutex_unlock(&pack_mutex); 981 return ptr; 982 } 983 984 void bpf_prog_pack_free(void *ptr, u32 size) 985 { 986 struct bpf_prog_pack *pack = NULL, *tmp; 987 unsigned int nbits; 988 unsigned long pos; 989 990 mutex_lock(&pack_mutex); 991 if (size > BPF_PROG_PACK_SIZE) { 992 bpf_jit_free_exec(ptr); 993 goto out; 994 } 995 996 list_for_each_entry(tmp, &pack_list, list) { 997 if (ptr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > ptr) { 998 pack = tmp; 999 break; 1000 } 1001 } 1002 1003 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 1004 goto out; 1005 1006 nbits = BPF_PROG_SIZE_TO_NBITS(size); 1007 pos = ((unsigned long)ptr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; 1008 1009 WARN_ONCE(bpf_arch_text_invalidate(ptr, size), 1010 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 1011 1012 bitmap_clear(pack->bitmap, pos, nbits); 1013 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 1014 BPF_PROG_CHUNK_COUNT, 0) == 0) { 1015 list_del(&pack->list); 1016 bpf_jit_free_exec(pack->ptr); 1017 kfree(pack); 1018 } 1019 out: 1020 mutex_unlock(&pack_mutex); 1021 } 1022 1023 static atomic_long_t bpf_jit_current; 1024 1025 /* Can be overridden by an arch's JIT compiler if it has a custom, 1026 * dedicated BPF backend memory area, or if neither of the two 1027 * below apply. 1028 */ 1029 u64 __weak bpf_jit_alloc_exec_limit(void) 1030 { 1031 #if defined(MODULES_VADDR) 1032 return MODULES_END - MODULES_VADDR; 1033 #else 1034 return VMALLOC_END - VMALLOC_START; 1035 #endif 1036 } 1037 1038 static int __init bpf_jit_charge_init(void) 1039 { 1040 /* Only used as heuristic here to derive limit. */ 1041 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 1042 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1, 1043 PAGE_SIZE), LONG_MAX); 1044 return 0; 1045 } 1046 pure_initcall(bpf_jit_charge_init); 1047 1048 int bpf_jit_charge_modmem(u32 size) 1049 { 1050 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { 1051 if (!bpf_capable()) { 1052 atomic_long_sub(size, &bpf_jit_current); 1053 return -EPERM; 1054 } 1055 } 1056 1057 return 0; 1058 } 1059 1060 void bpf_jit_uncharge_modmem(u32 size) 1061 { 1062 atomic_long_sub(size, &bpf_jit_current); 1063 } 1064 1065 void *__weak bpf_jit_alloc_exec(unsigned long size) 1066 { 1067 return execmem_alloc(EXECMEM_BPF, size); 1068 } 1069 1070 void __weak bpf_jit_free_exec(void *addr) 1071 { 1072 execmem_free(addr); 1073 } 1074 1075 struct bpf_binary_header * 1076 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1077 unsigned int alignment, 1078 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1079 { 1080 struct bpf_binary_header *hdr; 1081 u32 size, hole, start; 1082 1083 WARN_ON_ONCE(!is_power_of_2(alignment) || 1084 alignment > BPF_IMAGE_ALIGNMENT); 1085 1086 /* Most of BPF filters are really small, but if some of them 1087 * fill a page, allow at least 128 extra bytes to insert a 1088 * random section of illegal instructions. 1089 */ 1090 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1091 1092 if (bpf_jit_charge_modmem(size)) 1093 return NULL; 1094 hdr = bpf_jit_alloc_exec(size); 1095 if (!hdr) { 1096 bpf_jit_uncharge_modmem(size); 1097 return NULL; 1098 } 1099 1100 /* Fill space with illegal/arch-dep instructions. */ 1101 bpf_fill_ill_insns(hdr, size); 1102 1103 hdr->size = size; 1104 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1105 PAGE_SIZE - sizeof(*hdr)); 1106 start = get_random_u32_below(hole) & ~(alignment - 1); 1107 1108 /* Leave a random number of instructions before BPF code. */ 1109 *image_ptr = &hdr->image[start]; 1110 1111 return hdr; 1112 } 1113 1114 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1115 { 1116 u32 size = hdr->size; 1117 1118 bpf_jit_free_exec(hdr); 1119 bpf_jit_uncharge_modmem(size); 1120 } 1121 1122 /* Allocate jit binary from bpf_prog_pack allocator. 1123 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1124 * to the memory. To solve this problem, a RW buffer is also allocated at 1125 * as the same time. The JIT engine should calculate offsets based on the 1126 * RO memory address, but write JITed program to the RW buffer. Once the 1127 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1128 * the JITed program to the RO memory. 1129 */ 1130 struct bpf_binary_header * 1131 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1132 unsigned int alignment, 1133 struct bpf_binary_header **rw_header, 1134 u8 **rw_image, 1135 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1136 { 1137 struct bpf_binary_header *ro_header; 1138 u32 size, hole, start; 1139 1140 WARN_ON_ONCE(!is_power_of_2(alignment) || 1141 alignment > BPF_IMAGE_ALIGNMENT); 1142 1143 /* add 16 bytes for a random section of illegal instructions */ 1144 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1145 1146 if (bpf_jit_charge_modmem(size)) 1147 return NULL; 1148 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1149 if (!ro_header) { 1150 bpf_jit_uncharge_modmem(size); 1151 return NULL; 1152 } 1153 1154 *rw_header = kvmalloc(size, GFP_KERNEL); 1155 if (!*rw_header) { 1156 bpf_prog_pack_free(ro_header, size); 1157 bpf_jit_uncharge_modmem(size); 1158 return NULL; 1159 } 1160 1161 /* Fill space with illegal/arch-dep instructions. */ 1162 bpf_fill_ill_insns(*rw_header, size); 1163 (*rw_header)->size = size; 1164 1165 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1166 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1167 start = get_random_u32_below(hole) & ~(alignment - 1); 1168 1169 *image_ptr = &ro_header->image[start]; 1170 *rw_image = &(*rw_header)->image[start]; 1171 1172 return ro_header; 1173 } 1174 1175 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1176 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, 1177 struct bpf_binary_header *ro_header, 1178 struct bpf_binary_header *rw_header) 1179 { 1180 void *ptr; 1181 1182 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1183 1184 kvfree(rw_header); 1185 1186 if (IS_ERR(ptr)) { 1187 bpf_prog_pack_free(ro_header, ro_header->size); 1188 return PTR_ERR(ptr); 1189 } 1190 return 0; 1191 } 1192 1193 /* bpf_jit_binary_pack_free is called in two different scenarios: 1194 * 1) when the program is freed after; 1195 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1196 * For case 2), we need to free both the RO memory and the RW buffer. 1197 * 1198 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1199 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1200 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1201 * bpf_arch_text_copy (when jit fails). 1202 */ 1203 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1204 struct bpf_binary_header *rw_header) 1205 { 1206 u32 size = ro_header->size; 1207 1208 bpf_prog_pack_free(ro_header, size); 1209 kvfree(rw_header); 1210 bpf_jit_uncharge_modmem(size); 1211 } 1212 1213 struct bpf_binary_header * 1214 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp) 1215 { 1216 unsigned long real_start = (unsigned long)fp->bpf_func; 1217 unsigned long addr; 1218 1219 addr = real_start & BPF_PROG_CHUNK_MASK; 1220 return (void *)addr; 1221 } 1222 1223 static inline struct bpf_binary_header * 1224 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1225 { 1226 unsigned long real_start = (unsigned long)fp->bpf_func; 1227 unsigned long addr; 1228 1229 addr = real_start & PAGE_MASK; 1230 return (void *)addr; 1231 } 1232 1233 /* This symbol is only overridden by archs that have different 1234 * requirements than the usual eBPF JITs, f.e. when they only 1235 * implement cBPF JIT, do not set images read-only, etc. 1236 */ 1237 void __weak bpf_jit_free(struct bpf_prog *fp) 1238 { 1239 if (fp->jited) { 1240 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1241 1242 bpf_jit_binary_free(hdr); 1243 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1244 } 1245 1246 bpf_prog_unlock_free(fp); 1247 } 1248 1249 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1250 const struct bpf_insn *insn, bool extra_pass, 1251 u64 *func_addr, bool *func_addr_fixed) 1252 { 1253 s16 off = insn->off; 1254 s32 imm = insn->imm; 1255 u8 *addr; 1256 int err; 1257 1258 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1259 if (!*func_addr_fixed) { 1260 /* Place-holder address till the last pass has collected 1261 * all addresses for JITed subprograms in which case we 1262 * can pick them up from prog->aux. 1263 */ 1264 if (!extra_pass) 1265 addr = NULL; 1266 else if (prog->aux->func && 1267 off >= 0 && off < prog->aux->real_func_cnt) 1268 addr = (u8 *)prog->aux->func[off]->bpf_func; 1269 else 1270 return -EINVAL; 1271 } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && 1272 bpf_jit_supports_far_kfunc_call()) { 1273 err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr); 1274 if (err) 1275 return err; 1276 } else { 1277 /* Address of a BPF helper call. Since part of the core 1278 * kernel, it's always at a fixed location. __bpf_call_base 1279 * and the helper with imm relative to it are both in core 1280 * kernel. 1281 */ 1282 addr = (u8 *)__bpf_call_base + imm; 1283 } 1284 1285 *func_addr = (unsigned long)addr; 1286 return 0; 1287 } 1288 1289 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1290 const struct bpf_insn *aux, 1291 struct bpf_insn *to_buff, 1292 bool emit_zext) 1293 { 1294 struct bpf_insn *to = to_buff; 1295 u32 imm_rnd = get_random_u32(); 1296 s16 off; 1297 1298 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1299 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1300 1301 /* Constraints on AX register: 1302 * 1303 * AX register is inaccessible from user space. It is mapped in 1304 * all JITs, and used here for constant blinding rewrites. It is 1305 * typically "stateless" meaning its contents are only valid within 1306 * the executed instruction, but not across several instructions. 1307 * There are a few exceptions however which are further detailed 1308 * below. 1309 * 1310 * Constant blinding is only used by JITs, not in the interpreter. 1311 * The interpreter uses AX in some occasions as a local temporary 1312 * register e.g. in DIV or MOD instructions. 1313 * 1314 * In restricted circumstances, the verifier can also use the AX 1315 * register for rewrites as long as they do not interfere with 1316 * the above cases! 1317 */ 1318 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1319 goto out; 1320 1321 if (from->imm == 0 && 1322 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1323 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1324 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1325 goto out; 1326 } 1327 1328 switch (from->code) { 1329 case BPF_ALU | BPF_ADD | BPF_K: 1330 case BPF_ALU | BPF_SUB | BPF_K: 1331 case BPF_ALU | BPF_AND | BPF_K: 1332 case BPF_ALU | BPF_OR | BPF_K: 1333 case BPF_ALU | BPF_XOR | BPF_K: 1334 case BPF_ALU | BPF_MUL | BPF_K: 1335 case BPF_ALU | BPF_MOV | BPF_K: 1336 case BPF_ALU | BPF_DIV | BPF_K: 1337 case BPF_ALU | BPF_MOD | BPF_K: 1338 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1339 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1340 *to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off); 1341 break; 1342 1343 case BPF_ALU64 | BPF_ADD | BPF_K: 1344 case BPF_ALU64 | BPF_SUB | BPF_K: 1345 case BPF_ALU64 | BPF_AND | BPF_K: 1346 case BPF_ALU64 | BPF_OR | BPF_K: 1347 case BPF_ALU64 | BPF_XOR | BPF_K: 1348 case BPF_ALU64 | BPF_MUL | BPF_K: 1349 case BPF_ALU64 | BPF_MOV | BPF_K: 1350 case BPF_ALU64 | BPF_DIV | BPF_K: 1351 case BPF_ALU64 | BPF_MOD | BPF_K: 1352 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1353 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1354 *to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off); 1355 break; 1356 1357 case BPF_JMP | BPF_JEQ | BPF_K: 1358 case BPF_JMP | BPF_JNE | BPF_K: 1359 case BPF_JMP | BPF_JGT | BPF_K: 1360 case BPF_JMP | BPF_JLT | BPF_K: 1361 case BPF_JMP | BPF_JGE | BPF_K: 1362 case BPF_JMP | BPF_JLE | BPF_K: 1363 case BPF_JMP | BPF_JSGT | BPF_K: 1364 case BPF_JMP | BPF_JSLT | BPF_K: 1365 case BPF_JMP | BPF_JSGE | BPF_K: 1366 case BPF_JMP | BPF_JSLE | BPF_K: 1367 case BPF_JMP | BPF_JSET | BPF_K: 1368 /* Accommodate for extra offset in case of a backjump. */ 1369 off = from->off; 1370 if (off < 0) 1371 off -= 2; 1372 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1373 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1374 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1375 break; 1376 1377 case BPF_JMP32 | BPF_JEQ | BPF_K: 1378 case BPF_JMP32 | BPF_JNE | BPF_K: 1379 case BPF_JMP32 | BPF_JGT | BPF_K: 1380 case BPF_JMP32 | BPF_JLT | BPF_K: 1381 case BPF_JMP32 | BPF_JGE | BPF_K: 1382 case BPF_JMP32 | BPF_JLE | BPF_K: 1383 case BPF_JMP32 | BPF_JSGT | BPF_K: 1384 case BPF_JMP32 | BPF_JSLT | BPF_K: 1385 case BPF_JMP32 | BPF_JSGE | BPF_K: 1386 case BPF_JMP32 | BPF_JSLE | BPF_K: 1387 case BPF_JMP32 | BPF_JSET | BPF_K: 1388 /* Accommodate for extra offset in case of a backjump. */ 1389 off = from->off; 1390 if (off < 0) 1391 off -= 2; 1392 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1393 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1394 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1395 off); 1396 break; 1397 1398 case BPF_LD | BPF_IMM | BPF_DW: 1399 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1400 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1401 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1402 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1403 break; 1404 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1405 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1406 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1407 if (emit_zext) 1408 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1409 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1410 break; 1411 1412 case BPF_ST | BPF_MEM | BPF_DW: 1413 case BPF_ST | BPF_MEM | BPF_W: 1414 case BPF_ST | BPF_MEM | BPF_H: 1415 case BPF_ST | BPF_MEM | BPF_B: 1416 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1417 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1418 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1419 break; 1420 } 1421 out: 1422 return to - to_buff; 1423 } 1424 1425 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1426 gfp_t gfp_extra_flags) 1427 { 1428 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1429 struct bpf_prog *fp; 1430 1431 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1432 if (fp != NULL) { 1433 /* aux->prog still points to the fp_other one, so 1434 * when promoting the clone to the real program, 1435 * this still needs to be adapted. 1436 */ 1437 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1438 } 1439 1440 return fp; 1441 } 1442 1443 static void bpf_prog_clone_free(struct bpf_prog *fp) 1444 { 1445 /* aux was stolen by the other clone, so we cannot free 1446 * it from this path! It will be freed eventually by the 1447 * other program on release. 1448 * 1449 * At this point, we don't need a deferred release since 1450 * clone is guaranteed to not be locked. 1451 */ 1452 fp->aux = NULL; 1453 fp->stats = NULL; 1454 fp->active = NULL; 1455 __bpf_prog_free(fp); 1456 } 1457 1458 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1459 { 1460 /* We have to repoint aux->prog to self, as we don't 1461 * know whether fp here is the clone or the original. 1462 */ 1463 fp->aux->prog = fp; 1464 bpf_prog_clone_free(fp_other); 1465 } 1466 1467 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1468 { 1469 struct bpf_insn insn_buff[16], aux[2]; 1470 struct bpf_prog *clone, *tmp; 1471 int insn_delta, insn_cnt; 1472 struct bpf_insn *insn; 1473 int i, rewritten; 1474 1475 if (!prog->blinding_requested || prog->blinded) 1476 return prog; 1477 1478 clone = bpf_prog_clone_create(prog, GFP_USER); 1479 if (!clone) 1480 return ERR_PTR(-ENOMEM); 1481 1482 insn_cnt = clone->len; 1483 insn = clone->insnsi; 1484 1485 for (i = 0; i < insn_cnt; i++, insn++) { 1486 if (bpf_pseudo_func(insn)) { 1487 /* ld_imm64 with an address of bpf subprog is not 1488 * a user controlled constant. Don't randomize it, 1489 * since it will conflict with jit_subprogs() logic. 1490 */ 1491 insn++; 1492 i++; 1493 continue; 1494 } 1495 1496 /* We temporarily need to hold the original ld64 insn 1497 * so that we can still access the first part in the 1498 * second blinding run. 1499 */ 1500 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1501 insn[1].code == 0) 1502 memcpy(aux, insn, sizeof(aux)); 1503 1504 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1505 clone->aux->verifier_zext); 1506 if (!rewritten) 1507 continue; 1508 1509 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1510 if (IS_ERR(tmp)) { 1511 /* Patching may have repointed aux->prog during 1512 * realloc from the original one, so we need to 1513 * fix it up here on error. 1514 */ 1515 bpf_jit_prog_release_other(prog, clone); 1516 return tmp; 1517 } 1518 1519 clone = tmp; 1520 insn_delta = rewritten - 1; 1521 1522 /* Walk new program and skip insns we just inserted. */ 1523 insn = clone->insnsi + i + insn_delta; 1524 insn_cnt += insn_delta; 1525 i += insn_delta; 1526 } 1527 1528 clone->blinded = 1; 1529 return clone; 1530 } 1531 #endif /* CONFIG_BPF_JIT */ 1532 1533 /* Base function for offset calculation. Needs to go into .text section, 1534 * therefore keeping it non-static as well; will also be used by JITs 1535 * anyway later on, so do not let the compiler omit it. This also needs 1536 * to go into kallsyms for correlation from e.g. bpftool, so naming 1537 * must not change. 1538 */ 1539 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1540 { 1541 return 0; 1542 } 1543 EXPORT_SYMBOL_GPL(__bpf_call_base); 1544 1545 /* All UAPI available opcodes. */ 1546 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1547 /* 32 bit ALU operations. */ \ 1548 /* Register based. */ \ 1549 INSN_3(ALU, ADD, X), \ 1550 INSN_3(ALU, SUB, X), \ 1551 INSN_3(ALU, AND, X), \ 1552 INSN_3(ALU, OR, X), \ 1553 INSN_3(ALU, LSH, X), \ 1554 INSN_3(ALU, RSH, X), \ 1555 INSN_3(ALU, XOR, X), \ 1556 INSN_3(ALU, MUL, X), \ 1557 INSN_3(ALU, MOV, X), \ 1558 INSN_3(ALU, ARSH, X), \ 1559 INSN_3(ALU, DIV, X), \ 1560 INSN_3(ALU, MOD, X), \ 1561 INSN_2(ALU, NEG), \ 1562 INSN_3(ALU, END, TO_BE), \ 1563 INSN_3(ALU, END, TO_LE), \ 1564 /* Immediate based. */ \ 1565 INSN_3(ALU, ADD, K), \ 1566 INSN_3(ALU, SUB, K), \ 1567 INSN_3(ALU, AND, K), \ 1568 INSN_3(ALU, OR, K), \ 1569 INSN_3(ALU, LSH, K), \ 1570 INSN_3(ALU, RSH, K), \ 1571 INSN_3(ALU, XOR, K), \ 1572 INSN_3(ALU, MUL, K), \ 1573 INSN_3(ALU, MOV, K), \ 1574 INSN_3(ALU, ARSH, K), \ 1575 INSN_3(ALU, DIV, K), \ 1576 INSN_3(ALU, MOD, K), \ 1577 /* 64 bit ALU operations. */ \ 1578 /* Register based. */ \ 1579 INSN_3(ALU64, ADD, X), \ 1580 INSN_3(ALU64, SUB, X), \ 1581 INSN_3(ALU64, AND, X), \ 1582 INSN_3(ALU64, OR, X), \ 1583 INSN_3(ALU64, LSH, X), \ 1584 INSN_3(ALU64, RSH, X), \ 1585 INSN_3(ALU64, XOR, X), \ 1586 INSN_3(ALU64, MUL, X), \ 1587 INSN_3(ALU64, MOV, X), \ 1588 INSN_3(ALU64, ARSH, X), \ 1589 INSN_3(ALU64, DIV, X), \ 1590 INSN_3(ALU64, MOD, X), \ 1591 INSN_2(ALU64, NEG), \ 1592 INSN_3(ALU64, END, TO_LE), \ 1593 /* Immediate based. */ \ 1594 INSN_3(ALU64, ADD, K), \ 1595 INSN_3(ALU64, SUB, K), \ 1596 INSN_3(ALU64, AND, K), \ 1597 INSN_3(ALU64, OR, K), \ 1598 INSN_3(ALU64, LSH, K), \ 1599 INSN_3(ALU64, RSH, K), \ 1600 INSN_3(ALU64, XOR, K), \ 1601 INSN_3(ALU64, MUL, K), \ 1602 INSN_3(ALU64, MOV, K), \ 1603 INSN_3(ALU64, ARSH, K), \ 1604 INSN_3(ALU64, DIV, K), \ 1605 INSN_3(ALU64, MOD, K), \ 1606 /* Call instruction. */ \ 1607 INSN_2(JMP, CALL), \ 1608 /* Exit instruction. */ \ 1609 INSN_2(JMP, EXIT), \ 1610 /* 32-bit Jump instructions. */ \ 1611 /* Register based. */ \ 1612 INSN_3(JMP32, JEQ, X), \ 1613 INSN_3(JMP32, JNE, X), \ 1614 INSN_3(JMP32, JGT, X), \ 1615 INSN_3(JMP32, JLT, X), \ 1616 INSN_3(JMP32, JGE, X), \ 1617 INSN_3(JMP32, JLE, X), \ 1618 INSN_3(JMP32, JSGT, X), \ 1619 INSN_3(JMP32, JSLT, X), \ 1620 INSN_3(JMP32, JSGE, X), \ 1621 INSN_3(JMP32, JSLE, X), \ 1622 INSN_3(JMP32, JSET, X), \ 1623 /* Immediate based. */ \ 1624 INSN_3(JMP32, JEQ, K), \ 1625 INSN_3(JMP32, JNE, K), \ 1626 INSN_3(JMP32, JGT, K), \ 1627 INSN_3(JMP32, JLT, K), \ 1628 INSN_3(JMP32, JGE, K), \ 1629 INSN_3(JMP32, JLE, K), \ 1630 INSN_3(JMP32, JSGT, K), \ 1631 INSN_3(JMP32, JSLT, K), \ 1632 INSN_3(JMP32, JSGE, K), \ 1633 INSN_3(JMP32, JSLE, K), \ 1634 INSN_3(JMP32, JSET, K), \ 1635 /* Jump instructions. */ \ 1636 /* Register based. */ \ 1637 INSN_3(JMP, JEQ, X), \ 1638 INSN_3(JMP, JNE, X), \ 1639 INSN_3(JMP, JGT, X), \ 1640 INSN_3(JMP, JLT, X), \ 1641 INSN_3(JMP, JGE, X), \ 1642 INSN_3(JMP, JLE, X), \ 1643 INSN_3(JMP, JSGT, X), \ 1644 INSN_3(JMP, JSLT, X), \ 1645 INSN_3(JMP, JSGE, X), \ 1646 INSN_3(JMP, JSLE, X), \ 1647 INSN_3(JMP, JSET, X), \ 1648 /* Immediate based. */ \ 1649 INSN_3(JMP, JEQ, K), \ 1650 INSN_3(JMP, JNE, K), \ 1651 INSN_3(JMP, JGT, K), \ 1652 INSN_3(JMP, JLT, K), \ 1653 INSN_3(JMP, JGE, K), \ 1654 INSN_3(JMP, JLE, K), \ 1655 INSN_3(JMP, JSGT, K), \ 1656 INSN_3(JMP, JSLT, K), \ 1657 INSN_3(JMP, JSGE, K), \ 1658 INSN_3(JMP, JSLE, K), \ 1659 INSN_3(JMP, JSET, K), \ 1660 INSN_2(JMP, JA), \ 1661 INSN_2(JMP32, JA), \ 1662 /* Store instructions. */ \ 1663 /* Register based. */ \ 1664 INSN_3(STX, MEM, B), \ 1665 INSN_3(STX, MEM, H), \ 1666 INSN_3(STX, MEM, W), \ 1667 INSN_3(STX, MEM, DW), \ 1668 INSN_3(STX, ATOMIC, W), \ 1669 INSN_3(STX, ATOMIC, DW), \ 1670 /* Immediate based. */ \ 1671 INSN_3(ST, MEM, B), \ 1672 INSN_3(ST, MEM, H), \ 1673 INSN_3(ST, MEM, W), \ 1674 INSN_3(ST, MEM, DW), \ 1675 /* Load instructions. */ \ 1676 /* Register based. */ \ 1677 INSN_3(LDX, MEM, B), \ 1678 INSN_3(LDX, MEM, H), \ 1679 INSN_3(LDX, MEM, W), \ 1680 INSN_3(LDX, MEM, DW), \ 1681 INSN_3(LDX, MEMSX, B), \ 1682 INSN_3(LDX, MEMSX, H), \ 1683 INSN_3(LDX, MEMSX, W), \ 1684 /* Immediate based. */ \ 1685 INSN_3(LD, IMM, DW) 1686 1687 bool bpf_opcode_in_insntable(u8 code) 1688 { 1689 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1690 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1691 static const bool public_insntable[256] = { 1692 [0 ... 255] = false, 1693 /* Now overwrite non-defaults ... */ 1694 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1695 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1696 [BPF_LD | BPF_ABS | BPF_B] = true, 1697 [BPF_LD | BPF_ABS | BPF_H] = true, 1698 [BPF_LD | BPF_ABS | BPF_W] = true, 1699 [BPF_LD | BPF_IND | BPF_B] = true, 1700 [BPF_LD | BPF_IND | BPF_H] = true, 1701 [BPF_LD | BPF_IND | BPF_W] = true, 1702 [BPF_JMP | BPF_JCOND] = true, 1703 }; 1704 #undef BPF_INSN_3_TBL 1705 #undef BPF_INSN_2_TBL 1706 return public_insntable[code]; 1707 } 1708 1709 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1710 /** 1711 * ___bpf_prog_run - run eBPF program on a given context 1712 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1713 * @insn: is the array of eBPF instructions 1714 * 1715 * Decode and execute eBPF instructions. 1716 * 1717 * Return: whatever value is in %BPF_R0 at program exit 1718 */ 1719 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1720 { 1721 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1722 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1723 static const void * const jumptable[256] __annotate_jump_table = { 1724 [0 ... 255] = &&default_label, 1725 /* Now overwrite non-defaults ... */ 1726 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1727 /* Non-UAPI available opcodes. */ 1728 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1729 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1730 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1731 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1732 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1733 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1734 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1735 [BPF_LDX | BPF_PROBE_MEMSX | BPF_B] = &&LDX_PROBE_MEMSX_B, 1736 [BPF_LDX | BPF_PROBE_MEMSX | BPF_H] = &&LDX_PROBE_MEMSX_H, 1737 [BPF_LDX | BPF_PROBE_MEMSX | BPF_W] = &&LDX_PROBE_MEMSX_W, 1738 }; 1739 #undef BPF_INSN_3_LBL 1740 #undef BPF_INSN_2_LBL 1741 u32 tail_call_cnt = 0; 1742 1743 #define CONT ({ insn++; goto select_insn; }) 1744 #define CONT_JMP ({ insn++; goto select_insn; }) 1745 1746 select_insn: 1747 goto *jumptable[insn->code]; 1748 1749 /* Explicitly mask the register-based shift amounts with 63 or 31 1750 * to avoid undefined behavior. Normally this won't affect the 1751 * generated code, for example, in case of native 64 bit archs such 1752 * as x86-64 or arm64, the compiler is optimizing the AND away for 1753 * the interpreter. In case of JITs, each of the JIT backends compiles 1754 * the BPF shift operations to machine instructions which produce 1755 * implementation-defined results in such a case; the resulting 1756 * contents of the register may be arbitrary, but program behaviour 1757 * as a whole remains defined. In other words, in case of JIT backends, 1758 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1759 */ 1760 /* ALU (shifts) */ 1761 #define SHT(OPCODE, OP) \ 1762 ALU64_##OPCODE##_X: \ 1763 DST = DST OP (SRC & 63); \ 1764 CONT; \ 1765 ALU_##OPCODE##_X: \ 1766 DST = (u32) DST OP ((u32) SRC & 31); \ 1767 CONT; \ 1768 ALU64_##OPCODE##_K: \ 1769 DST = DST OP IMM; \ 1770 CONT; \ 1771 ALU_##OPCODE##_K: \ 1772 DST = (u32) DST OP (u32) IMM; \ 1773 CONT; 1774 /* ALU (rest) */ 1775 #define ALU(OPCODE, OP) \ 1776 ALU64_##OPCODE##_X: \ 1777 DST = DST OP SRC; \ 1778 CONT; \ 1779 ALU_##OPCODE##_X: \ 1780 DST = (u32) DST OP (u32) SRC; \ 1781 CONT; \ 1782 ALU64_##OPCODE##_K: \ 1783 DST = DST OP IMM; \ 1784 CONT; \ 1785 ALU_##OPCODE##_K: \ 1786 DST = (u32) DST OP (u32) IMM; \ 1787 CONT; 1788 ALU(ADD, +) 1789 ALU(SUB, -) 1790 ALU(AND, &) 1791 ALU(OR, |) 1792 ALU(XOR, ^) 1793 ALU(MUL, *) 1794 SHT(LSH, <<) 1795 SHT(RSH, >>) 1796 #undef SHT 1797 #undef ALU 1798 ALU_NEG: 1799 DST = (u32) -DST; 1800 CONT; 1801 ALU64_NEG: 1802 DST = -DST; 1803 CONT; 1804 ALU_MOV_X: 1805 switch (OFF) { 1806 case 0: 1807 DST = (u32) SRC; 1808 break; 1809 case 8: 1810 DST = (u32)(s8) SRC; 1811 break; 1812 case 16: 1813 DST = (u32)(s16) SRC; 1814 break; 1815 } 1816 CONT; 1817 ALU_MOV_K: 1818 DST = (u32) IMM; 1819 CONT; 1820 ALU64_MOV_X: 1821 switch (OFF) { 1822 case 0: 1823 DST = SRC; 1824 break; 1825 case 8: 1826 DST = (s8) SRC; 1827 break; 1828 case 16: 1829 DST = (s16) SRC; 1830 break; 1831 case 32: 1832 DST = (s32) SRC; 1833 break; 1834 } 1835 CONT; 1836 ALU64_MOV_K: 1837 DST = IMM; 1838 CONT; 1839 LD_IMM_DW: 1840 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1841 insn++; 1842 CONT; 1843 ALU_ARSH_X: 1844 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1845 CONT; 1846 ALU_ARSH_K: 1847 DST = (u64) (u32) (((s32) DST) >> IMM); 1848 CONT; 1849 ALU64_ARSH_X: 1850 (*(s64 *) &DST) >>= (SRC & 63); 1851 CONT; 1852 ALU64_ARSH_K: 1853 (*(s64 *) &DST) >>= IMM; 1854 CONT; 1855 ALU64_MOD_X: 1856 switch (OFF) { 1857 case 0: 1858 div64_u64_rem(DST, SRC, &AX); 1859 DST = AX; 1860 break; 1861 case 1: 1862 AX = div64_s64(DST, SRC); 1863 DST = DST - AX * SRC; 1864 break; 1865 } 1866 CONT; 1867 ALU_MOD_X: 1868 switch (OFF) { 1869 case 0: 1870 AX = (u32) DST; 1871 DST = do_div(AX, (u32) SRC); 1872 break; 1873 case 1: 1874 AX = abs((s32)DST); 1875 AX = do_div(AX, abs((s32)SRC)); 1876 if ((s32)DST < 0) 1877 DST = (u32)-AX; 1878 else 1879 DST = (u32)AX; 1880 break; 1881 } 1882 CONT; 1883 ALU64_MOD_K: 1884 switch (OFF) { 1885 case 0: 1886 div64_u64_rem(DST, IMM, &AX); 1887 DST = AX; 1888 break; 1889 case 1: 1890 AX = div64_s64(DST, IMM); 1891 DST = DST - AX * IMM; 1892 break; 1893 } 1894 CONT; 1895 ALU_MOD_K: 1896 switch (OFF) { 1897 case 0: 1898 AX = (u32) DST; 1899 DST = do_div(AX, (u32) IMM); 1900 break; 1901 case 1: 1902 AX = abs((s32)DST); 1903 AX = do_div(AX, abs((s32)IMM)); 1904 if ((s32)DST < 0) 1905 DST = (u32)-AX; 1906 else 1907 DST = (u32)AX; 1908 break; 1909 } 1910 CONT; 1911 ALU64_DIV_X: 1912 switch (OFF) { 1913 case 0: 1914 DST = div64_u64(DST, SRC); 1915 break; 1916 case 1: 1917 DST = div64_s64(DST, SRC); 1918 break; 1919 } 1920 CONT; 1921 ALU_DIV_X: 1922 switch (OFF) { 1923 case 0: 1924 AX = (u32) DST; 1925 do_div(AX, (u32) SRC); 1926 DST = (u32) AX; 1927 break; 1928 case 1: 1929 AX = abs((s32)DST); 1930 do_div(AX, abs((s32)SRC)); 1931 if (((s32)DST < 0) == ((s32)SRC < 0)) 1932 DST = (u32)AX; 1933 else 1934 DST = (u32)-AX; 1935 break; 1936 } 1937 CONT; 1938 ALU64_DIV_K: 1939 switch (OFF) { 1940 case 0: 1941 DST = div64_u64(DST, IMM); 1942 break; 1943 case 1: 1944 DST = div64_s64(DST, IMM); 1945 break; 1946 } 1947 CONT; 1948 ALU_DIV_K: 1949 switch (OFF) { 1950 case 0: 1951 AX = (u32) DST; 1952 do_div(AX, (u32) IMM); 1953 DST = (u32) AX; 1954 break; 1955 case 1: 1956 AX = abs((s32)DST); 1957 do_div(AX, abs((s32)IMM)); 1958 if (((s32)DST < 0) == ((s32)IMM < 0)) 1959 DST = (u32)AX; 1960 else 1961 DST = (u32)-AX; 1962 break; 1963 } 1964 CONT; 1965 ALU_END_TO_BE: 1966 switch (IMM) { 1967 case 16: 1968 DST = (__force u16) cpu_to_be16(DST); 1969 break; 1970 case 32: 1971 DST = (__force u32) cpu_to_be32(DST); 1972 break; 1973 case 64: 1974 DST = (__force u64) cpu_to_be64(DST); 1975 break; 1976 } 1977 CONT; 1978 ALU_END_TO_LE: 1979 switch (IMM) { 1980 case 16: 1981 DST = (__force u16) cpu_to_le16(DST); 1982 break; 1983 case 32: 1984 DST = (__force u32) cpu_to_le32(DST); 1985 break; 1986 case 64: 1987 DST = (__force u64) cpu_to_le64(DST); 1988 break; 1989 } 1990 CONT; 1991 ALU64_END_TO_LE: 1992 switch (IMM) { 1993 case 16: 1994 DST = (__force u16) __swab16(DST); 1995 break; 1996 case 32: 1997 DST = (__force u32) __swab32(DST); 1998 break; 1999 case 64: 2000 DST = (__force u64) __swab64(DST); 2001 break; 2002 } 2003 CONT; 2004 2005 /* CALL */ 2006 JMP_CALL: 2007 /* Function call scratches BPF_R1-BPF_R5 registers, 2008 * preserves BPF_R6-BPF_R9, and stores return value 2009 * into BPF_R0. 2010 */ 2011 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 2012 BPF_R4, BPF_R5); 2013 CONT; 2014 2015 JMP_CALL_ARGS: 2016 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 2017 BPF_R3, BPF_R4, 2018 BPF_R5, 2019 insn + insn->off + 1); 2020 CONT; 2021 2022 JMP_TAIL_CALL: { 2023 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 2024 struct bpf_array *array = container_of(map, struct bpf_array, map); 2025 struct bpf_prog *prog; 2026 u32 index = BPF_R3; 2027 2028 if (unlikely(index >= array->map.max_entries)) 2029 goto out; 2030 2031 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 2032 goto out; 2033 2034 tail_call_cnt++; 2035 2036 prog = READ_ONCE(array->ptrs[index]); 2037 if (!prog) 2038 goto out; 2039 2040 /* ARG1 at this point is guaranteed to point to CTX from 2041 * the verifier side due to the fact that the tail call is 2042 * handled like a helper, that is, bpf_tail_call_proto, 2043 * where arg1_type is ARG_PTR_TO_CTX. 2044 */ 2045 insn = prog->insnsi; 2046 goto select_insn; 2047 out: 2048 CONT; 2049 } 2050 JMP_JA: 2051 insn += insn->off; 2052 CONT; 2053 JMP32_JA: 2054 insn += insn->imm; 2055 CONT; 2056 JMP_EXIT: 2057 return BPF_R0; 2058 /* JMP */ 2059 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 2060 JMP_##OPCODE##_X: \ 2061 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 2062 insn += insn->off; \ 2063 CONT_JMP; \ 2064 } \ 2065 CONT; \ 2066 JMP32_##OPCODE##_X: \ 2067 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 2068 insn += insn->off; \ 2069 CONT_JMP; \ 2070 } \ 2071 CONT; \ 2072 JMP_##OPCODE##_K: \ 2073 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 2074 insn += insn->off; \ 2075 CONT_JMP; \ 2076 } \ 2077 CONT; \ 2078 JMP32_##OPCODE##_K: \ 2079 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 2080 insn += insn->off; \ 2081 CONT_JMP; \ 2082 } \ 2083 CONT; 2084 COND_JMP(u, JEQ, ==) 2085 COND_JMP(u, JNE, !=) 2086 COND_JMP(u, JGT, >) 2087 COND_JMP(u, JLT, <) 2088 COND_JMP(u, JGE, >=) 2089 COND_JMP(u, JLE, <=) 2090 COND_JMP(u, JSET, &) 2091 COND_JMP(s, JSGT, >) 2092 COND_JMP(s, JSLT, <) 2093 COND_JMP(s, JSGE, >=) 2094 COND_JMP(s, JSLE, <=) 2095 #undef COND_JMP 2096 /* ST, STX and LDX*/ 2097 ST_NOSPEC: 2098 /* Speculation barrier for mitigating Speculative Store Bypass. 2099 * In case of arm64, we rely on the firmware mitigation as 2100 * controlled via the ssbd kernel parameter. Whenever the 2101 * mitigation is enabled, it works for all of the kernel code 2102 * with no need to provide any additional instructions here. 2103 * In case of x86, we use 'lfence' insn for mitigation. We 2104 * reuse preexisting logic from Spectre v1 mitigation that 2105 * happens to produce the required code on x86 for v4 as well. 2106 */ 2107 barrier_nospec(); 2108 CONT; 2109 #define LDST(SIZEOP, SIZE) \ 2110 STX_MEM_##SIZEOP: \ 2111 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 2112 CONT; \ 2113 ST_MEM_##SIZEOP: \ 2114 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 2115 CONT; \ 2116 LDX_MEM_##SIZEOP: \ 2117 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 2118 CONT; \ 2119 LDX_PROBE_MEM_##SIZEOP: \ 2120 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ 2121 (const void *)(long) (SRC + insn->off)); \ 2122 DST = *((SIZE *)&DST); \ 2123 CONT; 2124 2125 LDST(B, u8) 2126 LDST(H, u16) 2127 LDST(W, u32) 2128 LDST(DW, u64) 2129 #undef LDST 2130 2131 #define LDSX(SIZEOP, SIZE) \ 2132 LDX_MEMSX_##SIZEOP: \ 2133 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 2134 CONT; \ 2135 LDX_PROBE_MEMSX_##SIZEOP: \ 2136 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ 2137 (const void *)(long) (SRC + insn->off)); \ 2138 DST = *((SIZE *)&DST); \ 2139 CONT; 2140 2141 LDSX(B, s8) 2142 LDSX(H, s16) 2143 LDSX(W, s32) 2144 #undef LDSX 2145 2146 #define ATOMIC_ALU_OP(BOP, KOP) \ 2147 case BOP: \ 2148 if (BPF_SIZE(insn->code) == BPF_W) \ 2149 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 2150 (DST + insn->off)); \ 2151 else \ 2152 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 2153 (DST + insn->off)); \ 2154 break; \ 2155 case BOP | BPF_FETCH: \ 2156 if (BPF_SIZE(insn->code) == BPF_W) \ 2157 SRC = (u32) atomic_fetch_##KOP( \ 2158 (u32) SRC, \ 2159 (atomic_t *)(unsigned long) (DST + insn->off)); \ 2160 else \ 2161 SRC = (u64) atomic64_fetch_##KOP( \ 2162 (u64) SRC, \ 2163 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 2164 break; 2165 2166 STX_ATOMIC_DW: 2167 STX_ATOMIC_W: 2168 switch (IMM) { 2169 ATOMIC_ALU_OP(BPF_ADD, add) 2170 ATOMIC_ALU_OP(BPF_AND, and) 2171 ATOMIC_ALU_OP(BPF_OR, or) 2172 ATOMIC_ALU_OP(BPF_XOR, xor) 2173 #undef ATOMIC_ALU_OP 2174 2175 case BPF_XCHG: 2176 if (BPF_SIZE(insn->code) == BPF_W) 2177 SRC = (u32) atomic_xchg( 2178 (atomic_t *)(unsigned long) (DST + insn->off), 2179 (u32) SRC); 2180 else 2181 SRC = (u64) atomic64_xchg( 2182 (atomic64_t *)(unsigned long) (DST + insn->off), 2183 (u64) SRC); 2184 break; 2185 case BPF_CMPXCHG: 2186 if (BPF_SIZE(insn->code) == BPF_W) 2187 BPF_R0 = (u32) atomic_cmpxchg( 2188 (atomic_t *)(unsigned long) (DST + insn->off), 2189 (u32) BPF_R0, (u32) SRC); 2190 else 2191 BPF_R0 = (u64) atomic64_cmpxchg( 2192 (atomic64_t *)(unsigned long) (DST + insn->off), 2193 (u64) BPF_R0, (u64) SRC); 2194 break; 2195 2196 default: 2197 goto default_label; 2198 } 2199 CONT; 2200 2201 default_label: 2202 /* If we ever reach this, we have a bug somewhere. Die hard here 2203 * instead of just returning 0; we could be somewhere in a subprog, 2204 * so execution could continue otherwise which we do /not/ want. 2205 * 2206 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 2207 */ 2208 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2209 insn->code, insn->imm); 2210 BUG_ON(1); 2211 return 0; 2212 } 2213 2214 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2215 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2216 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2217 { \ 2218 u64 stack[stack_size / sizeof(u64)]; \ 2219 u64 regs[MAX_BPF_EXT_REG] = {}; \ 2220 \ 2221 kmsan_unpoison_memory(stack, sizeof(stack)); \ 2222 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2223 ARG1 = (u64) (unsigned long) ctx; \ 2224 return ___bpf_prog_run(regs, insn); \ 2225 } 2226 2227 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2228 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2229 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2230 const struct bpf_insn *insn) \ 2231 { \ 2232 u64 stack[stack_size / sizeof(u64)]; \ 2233 u64 regs[MAX_BPF_EXT_REG]; \ 2234 \ 2235 kmsan_unpoison_memory(stack, sizeof(stack)); \ 2236 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2237 BPF_R1 = r1; \ 2238 BPF_R2 = r2; \ 2239 BPF_R3 = r3; \ 2240 BPF_R4 = r4; \ 2241 BPF_R5 = r5; \ 2242 return ___bpf_prog_run(regs, insn); \ 2243 } 2244 2245 #define EVAL1(FN, X) FN(X) 2246 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2247 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2248 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2249 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2250 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2251 2252 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2253 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2254 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2255 2256 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2257 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2258 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2259 2260 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2261 2262 static unsigned int (*interpreters[])(const void *ctx, 2263 const struct bpf_insn *insn) = { 2264 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2265 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2266 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2267 }; 2268 #undef PROG_NAME_LIST 2269 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2270 static __maybe_unused 2271 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2272 const struct bpf_insn *insn) = { 2273 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2274 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2275 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2276 }; 2277 #undef PROG_NAME_LIST 2278 2279 #ifdef CONFIG_BPF_SYSCALL 2280 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2281 { 2282 stack_depth = max_t(u32, stack_depth, 1); 2283 insn->off = (s16) insn->imm; 2284 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2285 __bpf_call_base_args; 2286 insn->code = BPF_JMP | BPF_CALL_ARGS; 2287 } 2288 #endif 2289 #else 2290 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2291 const struct bpf_insn *insn) 2292 { 2293 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2294 * is not working properly, so warn about it! 2295 */ 2296 WARN_ON_ONCE(1); 2297 return 0; 2298 } 2299 #endif 2300 2301 bool bpf_prog_map_compatible(struct bpf_map *map, 2302 const struct bpf_prog *fp) 2303 { 2304 enum bpf_prog_type prog_type = resolve_prog_type(fp); 2305 bool ret; 2306 2307 if (fp->kprobe_override) 2308 return false; 2309 2310 /* XDP programs inserted into maps are not guaranteed to run on 2311 * a particular netdev (and can run outside driver context entirely 2312 * in the case of devmap and cpumap). Until device checks 2313 * are implemented, prohibit adding dev-bound programs to program maps. 2314 */ 2315 if (bpf_prog_is_dev_bound(fp->aux)) 2316 return false; 2317 2318 spin_lock(&map->owner.lock); 2319 if (!map->owner.type) { 2320 /* There's no owner yet where we could check for 2321 * compatibility. 2322 */ 2323 map->owner.type = prog_type; 2324 map->owner.jited = fp->jited; 2325 map->owner.xdp_has_frags = fp->aux->xdp_has_frags; 2326 ret = true; 2327 } else { 2328 ret = map->owner.type == prog_type && 2329 map->owner.jited == fp->jited && 2330 map->owner.xdp_has_frags == fp->aux->xdp_has_frags; 2331 } 2332 spin_unlock(&map->owner.lock); 2333 2334 return ret; 2335 } 2336 2337 static int bpf_check_tail_call(const struct bpf_prog *fp) 2338 { 2339 struct bpf_prog_aux *aux = fp->aux; 2340 int i, ret = 0; 2341 2342 mutex_lock(&aux->used_maps_mutex); 2343 for (i = 0; i < aux->used_map_cnt; i++) { 2344 struct bpf_map *map = aux->used_maps[i]; 2345 2346 if (!map_type_contains_progs(map)) 2347 continue; 2348 2349 if (!bpf_prog_map_compatible(map, fp)) { 2350 ret = -EINVAL; 2351 goto out; 2352 } 2353 } 2354 2355 out: 2356 mutex_unlock(&aux->used_maps_mutex); 2357 return ret; 2358 } 2359 2360 static void bpf_prog_select_func(struct bpf_prog *fp) 2361 { 2362 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2363 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2364 2365 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 2366 #else 2367 fp->bpf_func = __bpf_prog_ret0_warn; 2368 #endif 2369 } 2370 2371 /** 2372 * bpf_prog_select_runtime - select exec runtime for BPF program 2373 * @fp: bpf_prog populated with BPF program 2374 * @err: pointer to error variable 2375 * 2376 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2377 * The BPF program will be executed via bpf_prog_run() function. 2378 * 2379 * Return: the &fp argument along with &err set to 0 for success or 2380 * a negative errno code on failure 2381 */ 2382 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2383 { 2384 /* In case of BPF to BPF calls, verifier did all the prep 2385 * work with regards to JITing, etc. 2386 */ 2387 bool jit_needed = false; 2388 2389 if (fp->bpf_func) 2390 goto finalize; 2391 2392 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2393 bpf_prog_has_kfunc_call(fp)) 2394 jit_needed = true; 2395 2396 bpf_prog_select_func(fp); 2397 2398 /* eBPF JITs can rewrite the program in case constant 2399 * blinding is active. However, in case of error during 2400 * blinding, bpf_int_jit_compile() must always return a 2401 * valid program, which in this case would simply not 2402 * be JITed, but falls back to the interpreter. 2403 */ 2404 if (!bpf_prog_is_offloaded(fp->aux)) { 2405 *err = bpf_prog_alloc_jited_linfo(fp); 2406 if (*err) 2407 return fp; 2408 2409 fp = bpf_int_jit_compile(fp); 2410 bpf_prog_jit_attempt_done(fp); 2411 if (!fp->jited && jit_needed) { 2412 *err = -ENOTSUPP; 2413 return fp; 2414 } 2415 } else { 2416 *err = bpf_prog_offload_compile(fp); 2417 if (*err) 2418 return fp; 2419 } 2420 2421 finalize: 2422 *err = bpf_prog_lock_ro(fp); 2423 if (*err) 2424 return fp; 2425 2426 /* The tail call compatibility check can only be done at 2427 * this late stage as we need to determine, if we deal 2428 * with JITed or non JITed program concatenations and not 2429 * all eBPF JITs might immediately support all features. 2430 */ 2431 *err = bpf_check_tail_call(fp); 2432 2433 return fp; 2434 } 2435 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2436 2437 static unsigned int __bpf_prog_ret1(const void *ctx, 2438 const struct bpf_insn *insn) 2439 { 2440 return 1; 2441 } 2442 2443 static struct bpf_prog_dummy { 2444 struct bpf_prog prog; 2445 } dummy_bpf_prog = { 2446 .prog = { 2447 .bpf_func = __bpf_prog_ret1, 2448 }, 2449 }; 2450 2451 struct bpf_empty_prog_array bpf_empty_prog_array = { 2452 .null_prog = NULL, 2453 }; 2454 EXPORT_SYMBOL(bpf_empty_prog_array); 2455 2456 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2457 { 2458 struct bpf_prog_array *p; 2459 2460 if (prog_cnt) 2461 p = kzalloc(struct_size(p, items, prog_cnt + 1), flags); 2462 else 2463 p = &bpf_empty_prog_array.hdr; 2464 2465 return p; 2466 } 2467 2468 void bpf_prog_array_free(struct bpf_prog_array *progs) 2469 { 2470 if (!progs || progs == &bpf_empty_prog_array.hdr) 2471 return; 2472 kfree_rcu(progs, rcu); 2473 } 2474 2475 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2476 { 2477 struct bpf_prog_array *progs; 2478 2479 /* If RCU Tasks Trace grace period implies RCU grace period, there is 2480 * no need to call kfree_rcu(), just call kfree() directly. 2481 */ 2482 progs = container_of(rcu, struct bpf_prog_array, rcu); 2483 if (rcu_trace_implies_rcu_gp()) 2484 kfree(progs); 2485 else 2486 kfree_rcu(progs, rcu); 2487 } 2488 2489 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2490 { 2491 if (!progs || progs == &bpf_empty_prog_array.hdr) 2492 return; 2493 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2494 } 2495 2496 int bpf_prog_array_length(struct bpf_prog_array *array) 2497 { 2498 struct bpf_prog_array_item *item; 2499 u32 cnt = 0; 2500 2501 for (item = array->items; item->prog; item++) 2502 if (item->prog != &dummy_bpf_prog.prog) 2503 cnt++; 2504 return cnt; 2505 } 2506 2507 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2508 { 2509 struct bpf_prog_array_item *item; 2510 2511 for (item = array->items; item->prog; item++) 2512 if (item->prog != &dummy_bpf_prog.prog) 2513 return false; 2514 return true; 2515 } 2516 2517 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2518 u32 *prog_ids, 2519 u32 request_cnt) 2520 { 2521 struct bpf_prog_array_item *item; 2522 int i = 0; 2523 2524 for (item = array->items; item->prog; item++) { 2525 if (item->prog == &dummy_bpf_prog.prog) 2526 continue; 2527 prog_ids[i] = item->prog->aux->id; 2528 if (++i == request_cnt) { 2529 item++; 2530 break; 2531 } 2532 } 2533 2534 return !!(item->prog); 2535 } 2536 2537 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2538 __u32 __user *prog_ids, u32 cnt) 2539 { 2540 unsigned long err = 0; 2541 bool nospc; 2542 u32 *ids; 2543 2544 /* users of this function are doing: 2545 * cnt = bpf_prog_array_length(); 2546 * if (cnt > 0) 2547 * bpf_prog_array_copy_to_user(..., cnt); 2548 * so below kcalloc doesn't need extra cnt > 0 check. 2549 */ 2550 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2551 if (!ids) 2552 return -ENOMEM; 2553 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2554 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2555 kfree(ids); 2556 if (err) 2557 return -EFAULT; 2558 if (nospc) 2559 return -ENOSPC; 2560 return 0; 2561 } 2562 2563 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2564 struct bpf_prog *old_prog) 2565 { 2566 struct bpf_prog_array_item *item; 2567 2568 for (item = array->items; item->prog; item++) 2569 if (item->prog == old_prog) { 2570 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2571 break; 2572 } 2573 } 2574 2575 /** 2576 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2577 * index into the program array with 2578 * a dummy no-op program. 2579 * @array: a bpf_prog_array 2580 * @index: the index of the program to replace 2581 * 2582 * Skips over dummy programs, by not counting them, when calculating 2583 * the position of the program to replace. 2584 * 2585 * Return: 2586 * * 0 - Success 2587 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2588 * * -ENOENT - Index out of range 2589 */ 2590 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2591 { 2592 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2593 } 2594 2595 /** 2596 * bpf_prog_array_update_at() - Updates the program at the given index 2597 * into the program array. 2598 * @array: a bpf_prog_array 2599 * @index: the index of the program to update 2600 * @prog: the program to insert into the array 2601 * 2602 * Skips over dummy programs, by not counting them, when calculating 2603 * the position of the program to update. 2604 * 2605 * Return: 2606 * * 0 - Success 2607 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2608 * * -ENOENT - Index out of range 2609 */ 2610 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2611 struct bpf_prog *prog) 2612 { 2613 struct bpf_prog_array_item *item; 2614 2615 if (unlikely(index < 0)) 2616 return -EINVAL; 2617 2618 for (item = array->items; item->prog; item++) { 2619 if (item->prog == &dummy_bpf_prog.prog) 2620 continue; 2621 if (!index) { 2622 WRITE_ONCE(item->prog, prog); 2623 return 0; 2624 } 2625 index--; 2626 } 2627 return -ENOENT; 2628 } 2629 2630 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2631 struct bpf_prog *exclude_prog, 2632 struct bpf_prog *include_prog, 2633 u64 bpf_cookie, 2634 struct bpf_prog_array **new_array) 2635 { 2636 int new_prog_cnt, carry_prog_cnt = 0; 2637 struct bpf_prog_array_item *existing, *new; 2638 struct bpf_prog_array *array; 2639 bool found_exclude = false; 2640 2641 /* Figure out how many existing progs we need to carry over to 2642 * the new array. 2643 */ 2644 if (old_array) { 2645 existing = old_array->items; 2646 for (; existing->prog; existing++) { 2647 if (existing->prog == exclude_prog) { 2648 found_exclude = true; 2649 continue; 2650 } 2651 if (existing->prog != &dummy_bpf_prog.prog) 2652 carry_prog_cnt++; 2653 if (existing->prog == include_prog) 2654 return -EEXIST; 2655 } 2656 } 2657 2658 if (exclude_prog && !found_exclude) 2659 return -ENOENT; 2660 2661 /* How many progs (not NULL) will be in the new array? */ 2662 new_prog_cnt = carry_prog_cnt; 2663 if (include_prog) 2664 new_prog_cnt += 1; 2665 2666 /* Do we have any prog (not NULL) in the new array? */ 2667 if (!new_prog_cnt) { 2668 *new_array = NULL; 2669 return 0; 2670 } 2671 2672 /* +1 as the end of prog_array is marked with NULL */ 2673 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2674 if (!array) 2675 return -ENOMEM; 2676 new = array->items; 2677 2678 /* Fill in the new prog array */ 2679 if (carry_prog_cnt) { 2680 existing = old_array->items; 2681 for (; existing->prog; existing++) { 2682 if (existing->prog == exclude_prog || 2683 existing->prog == &dummy_bpf_prog.prog) 2684 continue; 2685 2686 new->prog = existing->prog; 2687 new->bpf_cookie = existing->bpf_cookie; 2688 new++; 2689 } 2690 } 2691 if (include_prog) { 2692 new->prog = include_prog; 2693 new->bpf_cookie = bpf_cookie; 2694 new++; 2695 } 2696 new->prog = NULL; 2697 *new_array = array; 2698 return 0; 2699 } 2700 2701 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2702 u32 *prog_ids, u32 request_cnt, 2703 u32 *prog_cnt) 2704 { 2705 u32 cnt = 0; 2706 2707 if (array) 2708 cnt = bpf_prog_array_length(array); 2709 2710 *prog_cnt = cnt; 2711 2712 /* return early if user requested only program count or nothing to copy */ 2713 if (!request_cnt || !cnt) 2714 return 0; 2715 2716 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2717 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2718 : 0; 2719 } 2720 2721 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2722 struct bpf_map **used_maps, u32 len) 2723 { 2724 struct bpf_map *map; 2725 bool sleepable; 2726 u32 i; 2727 2728 sleepable = aux->prog->sleepable; 2729 for (i = 0; i < len; i++) { 2730 map = used_maps[i]; 2731 if (map->ops->map_poke_untrack) 2732 map->ops->map_poke_untrack(map, aux); 2733 if (sleepable) 2734 atomic64_dec(&map->sleepable_refcnt); 2735 bpf_map_put(map); 2736 } 2737 } 2738 2739 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2740 { 2741 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2742 kfree(aux->used_maps); 2743 } 2744 2745 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2746 struct btf_mod_pair *used_btfs, u32 len) 2747 { 2748 #ifdef CONFIG_BPF_SYSCALL 2749 struct btf_mod_pair *btf_mod; 2750 u32 i; 2751 2752 for (i = 0; i < len; i++) { 2753 btf_mod = &used_btfs[i]; 2754 if (btf_mod->module) 2755 module_put(btf_mod->module); 2756 btf_put(btf_mod->btf); 2757 } 2758 #endif 2759 } 2760 2761 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2762 { 2763 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2764 kfree(aux->used_btfs); 2765 } 2766 2767 static void bpf_prog_free_deferred(struct work_struct *work) 2768 { 2769 struct bpf_prog_aux *aux; 2770 int i; 2771 2772 aux = container_of(work, struct bpf_prog_aux, work); 2773 #ifdef CONFIG_BPF_SYSCALL 2774 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2775 #endif 2776 #ifdef CONFIG_CGROUP_BPF 2777 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2778 bpf_cgroup_atype_put(aux->cgroup_atype); 2779 #endif 2780 bpf_free_used_maps(aux); 2781 bpf_free_used_btfs(aux); 2782 if (bpf_prog_is_dev_bound(aux)) 2783 bpf_prog_dev_bound_destroy(aux->prog); 2784 #ifdef CONFIG_PERF_EVENTS 2785 if (aux->prog->has_callchain_buf) 2786 put_callchain_buffers(); 2787 #endif 2788 if (aux->dst_trampoline) 2789 bpf_trampoline_put(aux->dst_trampoline); 2790 for (i = 0; i < aux->real_func_cnt; i++) { 2791 /* We can just unlink the subprog poke descriptor table as 2792 * it was originally linked to the main program and is also 2793 * released along with it. 2794 */ 2795 aux->func[i]->aux->poke_tab = NULL; 2796 bpf_jit_free(aux->func[i]); 2797 } 2798 if (aux->real_func_cnt) { 2799 kfree(aux->func); 2800 bpf_prog_unlock_free(aux->prog); 2801 } else { 2802 bpf_jit_free(aux->prog); 2803 } 2804 } 2805 2806 void bpf_prog_free(struct bpf_prog *fp) 2807 { 2808 struct bpf_prog_aux *aux = fp->aux; 2809 2810 if (aux->dst_prog) 2811 bpf_prog_put(aux->dst_prog); 2812 bpf_token_put(aux->token); 2813 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2814 schedule_work(&aux->work); 2815 } 2816 EXPORT_SYMBOL_GPL(bpf_prog_free); 2817 2818 /* RNG for unprivileged user space with separated state from prandom_u32(). */ 2819 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2820 2821 void bpf_user_rnd_init_once(void) 2822 { 2823 prandom_init_once(&bpf_user_rnd_state); 2824 } 2825 2826 BPF_CALL_0(bpf_user_rnd_u32) 2827 { 2828 /* Should someone ever have the rather unwise idea to use some 2829 * of the registers passed into this function, then note that 2830 * this function is called from native eBPF and classic-to-eBPF 2831 * transformations. Register assignments from both sides are 2832 * different, f.e. classic always sets fn(ctx, A, X) here. 2833 */ 2834 struct rnd_state *state; 2835 u32 res; 2836 2837 state = &get_cpu_var(bpf_user_rnd_state); 2838 res = prandom_u32_state(state); 2839 put_cpu_var(bpf_user_rnd_state); 2840 2841 return res; 2842 } 2843 2844 BPF_CALL_0(bpf_get_raw_cpu_id) 2845 { 2846 return raw_smp_processor_id(); 2847 } 2848 2849 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2850 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2851 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2852 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2853 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2854 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2855 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2856 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2857 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2858 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2859 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2860 2861 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2862 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2863 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2864 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2865 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2866 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2867 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak; 2868 2869 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2870 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2871 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2872 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2873 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2874 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2875 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2876 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2877 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2878 const struct bpf_func_proto bpf_set_retval_proto __weak; 2879 const struct bpf_func_proto bpf_get_retval_proto __weak; 2880 2881 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2882 { 2883 return NULL; 2884 } 2885 2886 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2887 { 2888 return NULL; 2889 } 2890 2891 u64 __weak 2892 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2893 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2894 { 2895 return -ENOTSUPP; 2896 } 2897 EXPORT_SYMBOL_GPL(bpf_event_output); 2898 2899 /* Always built-in helper functions. */ 2900 const struct bpf_func_proto bpf_tail_call_proto = { 2901 .func = NULL, 2902 .gpl_only = false, 2903 .ret_type = RET_VOID, 2904 .arg1_type = ARG_PTR_TO_CTX, 2905 .arg2_type = ARG_CONST_MAP_PTR, 2906 .arg3_type = ARG_ANYTHING, 2907 }; 2908 2909 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2910 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2911 * eBPF and implicitly also cBPF can get JITed! 2912 */ 2913 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2914 { 2915 return prog; 2916 } 2917 2918 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2919 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2920 */ 2921 void __weak bpf_jit_compile(struct bpf_prog *prog) 2922 { 2923 } 2924 2925 bool __weak bpf_helper_changes_pkt_data(void *func) 2926 { 2927 return false; 2928 } 2929 2930 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2931 * analysis code and wants explicit zero extension inserted by verifier. 2932 * Otherwise, return FALSE. 2933 * 2934 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2935 * you don't override this. JITs that don't want these extra insns can detect 2936 * them using insn_is_zext. 2937 */ 2938 bool __weak bpf_jit_needs_zext(void) 2939 { 2940 return false; 2941 } 2942 2943 /* Return true if the JIT inlines the call to the helper corresponding to 2944 * the imm. 2945 * 2946 * The verifier will not patch the insn->imm for the call to the helper if 2947 * this returns true. 2948 */ 2949 bool __weak bpf_jit_inlines_helper_call(s32 imm) 2950 { 2951 return false; 2952 } 2953 2954 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 2955 bool __weak bpf_jit_supports_subprog_tailcalls(void) 2956 { 2957 return false; 2958 } 2959 2960 bool __weak bpf_jit_supports_percpu_insn(void) 2961 { 2962 return false; 2963 } 2964 2965 bool __weak bpf_jit_supports_kfunc_call(void) 2966 { 2967 return false; 2968 } 2969 2970 bool __weak bpf_jit_supports_far_kfunc_call(void) 2971 { 2972 return false; 2973 } 2974 2975 bool __weak bpf_jit_supports_arena(void) 2976 { 2977 return false; 2978 } 2979 2980 bool __weak bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena) 2981 { 2982 return false; 2983 } 2984 2985 u64 __weak bpf_arch_uaddress_limit(void) 2986 { 2987 #if defined(CONFIG_64BIT) && defined(CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE) 2988 return TASK_SIZE; 2989 #else 2990 return 0; 2991 #endif 2992 } 2993 2994 /* Return TRUE if the JIT backend satisfies the following two conditions: 2995 * 1) JIT backend supports atomic_xchg() on pointer-sized words. 2996 * 2) Under the specific arch, the implementation of xchg() is the same 2997 * as atomic_xchg() on pointer-sized words. 2998 */ 2999 bool __weak bpf_jit_supports_ptr_xchg(void) 3000 { 3001 return false; 3002 } 3003 3004 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 3005 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 3006 */ 3007 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 3008 int len) 3009 { 3010 return -EFAULT; 3011 } 3012 3013 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 3014 void *addr1, void *addr2) 3015 { 3016 return -ENOTSUPP; 3017 } 3018 3019 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 3020 { 3021 return ERR_PTR(-ENOTSUPP); 3022 } 3023 3024 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 3025 { 3026 return -ENOTSUPP; 3027 } 3028 3029 bool __weak bpf_jit_supports_exceptions(void) 3030 { 3031 return false; 3032 } 3033 3034 void __weak arch_bpf_stack_walk(bool (*consume_fn)(void *cookie, u64 ip, u64 sp, u64 bp), void *cookie) 3035 { 3036 } 3037 3038 /* for configs without MMU or 32-bit */ 3039 __weak const struct bpf_map_ops arena_map_ops; 3040 __weak u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena) 3041 { 3042 return 0; 3043 } 3044 __weak u64 bpf_arena_get_kern_vm_start(struct bpf_arena *arena) 3045 { 3046 return 0; 3047 } 3048 3049 #ifdef CONFIG_BPF_SYSCALL 3050 static int __init bpf_global_ma_init(void) 3051 { 3052 int ret; 3053 3054 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); 3055 bpf_global_ma_set = !ret; 3056 return ret; 3057 } 3058 late_initcall(bpf_global_ma_init); 3059 #endif 3060 3061 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 3062 EXPORT_SYMBOL(bpf_stats_enabled_key); 3063 3064 /* All definitions of tracepoints related to BPF. */ 3065 #define CREATE_TRACE_POINTS 3066 #include <linux/bpf_trace.h> 3067 3068 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 3069 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 3070