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 <crypto/sha1.h> 22 #include <linux/filter.h> 23 #include <linux/skbuff.h> 24 #include <linux/vmalloc.h> 25 #include <linux/prandom.h> 26 #include <linux/bpf.h> 27 #include <linux/btf.h> 28 #include <linux/objtool.h> 29 #include <linux/overflow.h> 30 #include <linux/rbtree_latch.h> 31 #include <linux/kallsyms.h> 32 #include <linux/rcupdate.h> 33 #include <linux/perf_event.h> 34 #include <linux/extable.h> 35 #include <linux/log2.h> 36 #include <linux/bpf_verifier.h> 37 #include <linux/nodemask.h> 38 #include <linux/nospec.h> 39 #include <linux/bpf_mem_alloc.h> 40 #include <linux/memcontrol.h> 41 #include <linux/execmem.h> 42 #include <crypto/sha2.h> 43 44 #include <asm/barrier.h> 45 #include <linux/unaligned.h> 46 47 /* Registers */ 48 #define BPF_R0 regs[BPF_REG_0] 49 #define BPF_R1 regs[BPF_REG_1] 50 #define BPF_R2 regs[BPF_REG_2] 51 #define BPF_R3 regs[BPF_REG_3] 52 #define BPF_R4 regs[BPF_REG_4] 53 #define BPF_R5 regs[BPF_REG_5] 54 #define BPF_R6 regs[BPF_REG_6] 55 #define BPF_R7 regs[BPF_REG_7] 56 #define BPF_R8 regs[BPF_REG_8] 57 #define BPF_R9 regs[BPF_REG_9] 58 #define BPF_R10 regs[BPF_REG_10] 59 60 /* Named registers */ 61 #define DST regs[insn->dst_reg] 62 #define SRC regs[insn->src_reg] 63 #define FP regs[BPF_REG_FP] 64 #define AX regs[BPF_REG_AX] 65 #define ARG1 regs[BPF_REG_ARG1] 66 #define CTX regs[BPF_REG_CTX] 67 #define OFF insn->off 68 #define IMM insn->imm 69 70 struct bpf_mem_alloc bpf_global_ma; 71 bool bpf_global_ma_set; 72 73 /* No hurry in this branch 74 * 75 * Exported for the bpf jit load helper. 76 */ 77 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 78 { 79 u8 *ptr = NULL; 80 81 if (k >= SKF_NET_OFF) { 82 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 83 } else if (k >= SKF_LL_OFF) { 84 if (unlikely(!skb_mac_header_was_set(skb))) 85 return NULL; 86 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 87 } 88 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 89 return ptr; 90 91 return NULL; 92 } 93 94 /* tell bpf programs that include vmlinux.h kernel's PAGE_SIZE */ 95 enum page_size_enum { 96 __PAGE_SIZE = PAGE_SIZE 97 }; 98 99 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 100 { 101 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 102 struct bpf_prog_aux *aux; 103 struct bpf_prog *fp; 104 105 size = round_up(size, __PAGE_SIZE); 106 fp = __vmalloc(size, gfp_flags); 107 if (fp == NULL) 108 return NULL; 109 110 aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 111 if (aux == NULL) { 112 vfree(fp); 113 return NULL; 114 } 115 fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 116 if (!fp->active) { 117 vfree(fp); 118 kfree(aux); 119 return NULL; 120 } 121 122 fp->pages = size / PAGE_SIZE; 123 fp->aux = aux; 124 fp->aux->main_prog_aux = aux; 125 fp->aux->prog = fp; 126 fp->jit_requested = ebpf_jit_enabled(); 127 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 128 #ifdef CONFIG_CGROUP_BPF 129 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 130 #endif 131 132 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 133 #ifdef CONFIG_FINEIBT 134 INIT_LIST_HEAD_RCU(&fp->aux->ksym_prefix.lnode); 135 #endif 136 mutex_init(&fp->aux->used_maps_mutex); 137 mutex_init(&fp->aux->ext_mutex); 138 mutex_init(&fp->aux->dst_mutex); 139 140 #ifdef CONFIG_BPF_SYSCALL 141 bpf_prog_stream_init(fp); 142 #endif 143 144 return fp; 145 } 146 147 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 148 { 149 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 150 struct bpf_prog *prog; 151 int cpu; 152 153 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 154 if (!prog) 155 return NULL; 156 157 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 158 if (!prog->stats) { 159 free_percpu(prog->active); 160 kfree(prog->aux); 161 vfree(prog); 162 return NULL; 163 } 164 165 for_each_possible_cpu(cpu) { 166 struct bpf_prog_stats *pstats; 167 168 pstats = per_cpu_ptr(prog->stats, cpu); 169 u64_stats_init(&pstats->syncp); 170 } 171 return prog; 172 } 173 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 174 175 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 176 { 177 if (!prog->aux->nr_linfo || !prog->jit_requested) 178 return 0; 179 180 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 181 sizeof(*prog->aux->jited_linfo), 182 bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN)); 183 if (!prog->aux->jited_linfo) 184 return -ENOMEM; 185 186 return 0; 187 } 188 189 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 190 { 191 if (prog->aux->jited_linfo && 192 (!prog->jited || !prog->aux->jited_linfo[0])) { 193 kvfree(prog->aux->jited_linfo); 194 prog->aux->jited_linfo = NULL; 195 } 196 197 kfree(prog->aux->kfunc_tab); 198 prog->aux->kfunc_tab = NULL; 199 } 200 201 /* The jit engine is responsible to provide an array 202 * for insn_off to the jited_off mapping (insn_to_jit_off). 203 * 204 * The idx to this array is the insn_off. Hence, the insn_off 205 * here is relative to the prog itself instead of the main prog. 206 * This array has one entry for each xlated bpf insn. 207 * 208 * jited_off is the byte off to the end of the jited insn. 209 * 210 * Hence, with 211 * insn_start: 212 * The first bpf insn off of the prog. The insn off 213 * here is relative to the main prog. 214 * e.g. if prog is a subprog, insn_start > 0 215 * linfo_idx: 216 * The prog's idx to prog->aux->linfo and jited_linfo 217 * 218 * jited_linfo[linfo_idx] = prog->bpf_func 219 * 220 * For i > linfo_idx, 221 * 222 * jited_linfo[i] = prog->bpf_func + 223 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 224 */ 225 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 226 const u32 *insn_to_jit_off) 227 { 228 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 229 const struct bpf_line_info *linfo; 230 void **jited_linfo; 231 232 if (!prog->aux->jited_linfo || prog->aux->func_idx > prog->aux->func_cnt) 233 /* Userspace did not provide linfo */ 234 return; 235 236 linfo_idx = prog->aux->linfo_idx; 237 linfo = &prog->aux->linfo[linfo_idx]; 238 insn_start = linfo[0].insn_off; 239 insn_end = insn_start + prog->len; 240 241 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 242 jited_linfo[0] = prog->bpf_func; 243 244 nr_linfo = prog->aux->nr_linfo - linfo_idx; 245 246 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 247 /* The verifier ensures that linfo[i].insn_off is 248 * strictly increasing 249 */ 250 jited_linfo[i] = prog->bpf_func + 251 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 252 } 253 254 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 255 gfp_t gfp_extra_flags) 256 { 257 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 258 struct bpf_prog *fp; 259 u32 pages; 260 261 size = round_up(size, PAGE_SIZE); 262 pages = size / PAGE_SIZE; 263 if (pages <= fp_old->pages) 264 return fp_old; 265 266 fp = __vmalloc(size, gfp_flags); 267 if (fp) { 268 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 269 fp->pages = pages; 270 fp->aux->prog = fp; 271 272 /* We keep fp->aux from fp_old around in the new 273 * reallocated structure. 274 */ 275 fp_old->aux = NULL; 276 fp_old->stats = NULL; 277 fp_old->active = NULL; 278 __bpf_prog_free(fp_old); 279 } 280 281 return fp; 282 } 283 284 void __bpf_prog_free(struct bpf_prog *fp) 285 { 286 if (fp->aux) { 287 mutex_destroy(&fp->aux->used_maps_mutex); 288 mutex_destroy(&fp->aux->dst_mutex); 289 kfree(fp->aux->poke_tab); 290 kfree(fp->aux); 291 } 292 free_percpu(fp->stats); 293 free_percpu(fp->active); 294 vfree(fp); 295 } 296 297 int bpf_prog_calc_tag(struct bpf_prog *fp) 298 { 299 size_t size = bpf_prog_insn_size(fp); 300 struct bpf_insn *dst; 301 bool was_ld_map; 302 u32 i; 303 304 dst = vmalloc(size); 305 if (!dst) 306 return -ENOMEM; 307 308 /* We need to take out the map fd for the digest calculation 309 * since they are unstable from user space side. 310 */ 311 for (i = 0, was_ld_map = false; i < fp->len; i++) { 312 dst[i] = fp->insnsi[i]; 313 if (!was_ld_map && 314 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 315 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 316 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 317 was_ld_map = true; 318 dst[i].imm = 0; 319 } else if (was_ld_map && 320 dst[i].code == 0 && 321 dst[i].dst_reg == 0 && 322 dst[i].src_reg == 0 && 323 dst[i].off == 0) { 324 was_ld_map = false; 325 dst[i].imm = 0; 326 } else { 327 was_ld_map = false; 328 } 329 } 330 sha256((u8 *)dst, size, fp->digest); 331 vfree(dst); 332 return 0; 333 } 334 335 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 336 s32 end_new, s32 curr, const bool probe_pass) 337 { 338 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 339 s32 delta = end_new - end_old; 340 s64 imm = insn->imm; 341 342 if (curr < pos && curr + imm + 1 >= end_old) 343 imm += delta; 344 else if (curr >= end_new && curr + imm + 1 < end_new) 345 imm -= delta; 346 if (imm < imm_min || imm > imm_max) 347 return -ERANGE; 348 if (!probe_pass) 349 insn->imm = imm; 350 return 0; 351 } 352 353 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 354 s32 end_new, s32 curr, const bool probe_pass) 355 { 356 s64 off_min, off_max, off; 357 s32 delta = end_new - end_old; 358 359 if (insn->code == (BPF_JMP32 | BPF_JA)) { 360 off = insn->imm; 361 off_min = S32_MIN; 362 off_max = S32_MAX; 363 } else { 364 off = insn->off; 365 off_min = S16_MIN; 366 off_max = S16_MAX; 367 } 368 369 if (curr < pos && curr + off + 1 >= end_old) 370 off += delta; 371 else if (curr >= end_new && curr + off + 1 < end_new) 372 off -= delta; 373 if (off < off_min || off > off_max) 374 return -ERANGE; 375 if (!probe_pass) { 376 if (insn->code == (BPF_JMP32 | BPF_JA)) 377 insn->imm = off; 378 else 379 insn->off = off; 380 } 381 return 0; 382 } 383 384 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 385 s32 end_new, const bool probe_pass) 386 { 387 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 388 struct bpf_insn *insn = prog->insnsi; 389 int ret = 0; 390 391 for (i = 0; i < insn_cnt; i++, insn++) { 392 u8 code; 393 394 /* In the probing pass we still operate on the original, 395 * unpatched image in order to check overflows before we 396 * do any other adjustments. Therefore skip the patchlet. 397 */ 398 if (probe_pass && i == pos) { 399 i = end_new; 400 insn = prog->insnsi + end_old; 401 } 402 if (bpf_pseudo_func(insn)) { 403 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 404 end_new, i, probe_pass); 405 if (ret) 406 return ret; 407 continue; 408 } 409 code = insn->code; 410 if ((BPF_CLASS(code) != BPF_JMP && 411 BPF_CLASS(code) != BPF_JMP32) || 412 BPF_OP(code) == BPF_EXIT) 413 continue; 414 /* Adjust offset of jmps if we cross patch boundaries. */ 415 if (BPF_OP(code) == BPF_CALL) { 416 if (insn->src_reg != BPF_PSEUDO_CALL) 417 continue; 418 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 419 end_new, i, probe_pass); 420 } else { 421 ret = bpf_adj_delta_to_off(insn, pos, end_old, 422 end_new, i, probe_pass); 423 } 424 if (ret) 425 break; 426 } 427 428 return ret; 429 } 430 431 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 432 { 433 struct bpf_line_info *linfo; 434 u32 i, nr_linfo; 435 436 nr_linfo = prog->aux->nr_linfo; 437 if (!nr_linfo || !delta) 438 return; 439 440 linfo = prog->aux->linfo; 441 442 for (i = 0; i < nr_linfo; i++) 443 if (off < linfo[i].insn_off) 444 break; 445 446 /* Push all off < linfo[i].insn_off by delta */ 447 for (; i < nr_linfo; i++) 448 linfo[i].insn_off += delta; 449 } 450 451 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 452 const struct bpf_insn *patch, u32 len) 453 { 454 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 455 const u32 cnt_max = S16_MAX; 456 struct bpf_prog *prog_adj; 457 int err; 458 459 /* Since our patchlet doesn't expand the image, we're done. */ 460 if (insn_delta == 0) { 461 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 462 return prog; 463 } 464 465 insn_adj_cnt = prog->len + insn_delta; 466 467 /* Reject anything that would potentially let the insn->off 468 * target overflow when we have excessive program expansions. 469 * We need to probe here before we do any reallocation where 470 * we afterwards may not fail anymore. 471 */ 472 if (insn_adj_cnt > cnt_max && 473 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 474 return ERR_PTR(err); 475 476 /* Several new instructions need to be inserted. Make room 477 * for them. Likely, there's no need for a new allocation as 478 * last page could have large enough tailroom. 479 */ 480 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 481 GFP_USER); 482 if (!prog_adj) 483 return ERR_PTR(-ENOMEM); 484 485 prog_adj->len = insn_adj_cnt; 486 487 /* Patching happens in 3 steps: 488 * 489 * 1) Move over tail of insnsi from next instruction onwards, 490 * so we can patch the single target insn with one or more 491 * new ones (patching is always from 1 to n insns, n > 0). 492 * 2) Inject new instructions at the target location. 493 * 3) Adjust branch offsets if necessary. 494 */ 495 insn_rest = insn_adj_cnt - off - len; 496 497 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 498 sizeof(*patch) * insn_rest); 499 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 500 501 /* We are guaranteed to not fail at this point, otherwise 502 * the ship has sailed to reverse to the original state. An 503 * overflow cannot happen at this point. 504 */ 505 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 506 507 bpf_adj_linfo(prog_adj, off, insn_delta); 508 509 return prog_adj; 510 } 511 512 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 513 { 514 int err; 515 516 /* Branch offsets can't overflow when program is shrinking, no need 517 * to call bpf_adj_branches(..., true) here 518 */ 519 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 520 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 521 prog->len -= cnt; 522 523 err = bpf_adj_branches(prog, off, off + cnt, off, false); 524 WARN_ON_ONCE(err); 525 return err; 526 } 527 528 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 529 { 530 int i; 531 532 for (i = 0; i < fp->aux->real_func_cnt; i++) 533 bpf_prog_kallsyms_del(fp->aux->func[i]); 534 } 535 536 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 537 { 538 bpf_prog_kallsyms_del_subprogs(fp); 539 bpf_prog_kallsyms_del(fp); 540 } 541 542 #ifdef CONFIG_BPF_JIT 543 /* All BPF JIT sysctl knobs here. */ 544 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 545 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 546 int bpf_jit_harden __read_mostly; 547 long bpf_jit_limit __read_mostly; 548 long bpf_jit_limit_max __read_mostly; 549 550 static void 551 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 552 { 553 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 554 555 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 556 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 557 } 558 559 static void 560 bpf_prog_ksym_set_name(struct bpf_prog *prog) 561 { 562 char *sym = prog->aux->ksym.name; 563 const char *end = sym + KSYM_NAME_LEN; 564 const struct btf_type *type; 565 const char *func_name; 566 567 BUILD_BUG_ON(sizeof("bpf_prog_") + 568 sizeof(prog->tag) * 2 + 569 /* name has been null terminated. 570 * We should need +1 for the '_' preceding 571 * the name. However, the null character 572 * is double counted between the name and the 573 * sizeof("bpf_prog_") above, so we omit 574 * the +1 here. 575 */ 576 sizeof(prog->aux->name) > KSYM_NAME_LEN); 577 578 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 579 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 580 581 /* prog->aux->name will be ignored if full btf name is available */ 582 if (prog->aux->func_info_cnt && prog->aux->func_idx < prog->aux->func_info_cnt) { 583 type = btf_type_by_id(prog->aux->btf, 584 prog->aux->func_info[prog->aux->func_idx].type_id); 585 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 586 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 587 return; 588 } 589 590 if (prog->aux->name[0]) 591 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 592 else 593 *sym = 0; 594 } 595 596 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 597 { 598 return container_of(n, struct bpf_ksym, tnode)->start; 599 } 600 601 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 602 struct latch_tree_node *b) 603 { 604 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 605 } 606 607 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 608 { 609 unsigned long val = (unsigned long)key; 610 const struct bpf_ksym *ksym; 611 612 ksym = container_of(n, struct bpf_ksym, tnode); 613 614 if (val < ksym->start) 615 return -1; 616 /* Ensure that we detect return addresses as part of the program, when 617 * the final instruction is a call for a program part of the stack 618 * trace. Therefore, do val > ksym->end instead of val >= ksym->end. 619 */ 620 if (val > ksym->end) 621 return 1; 622 623 return 0; 624 } 625 626 static const struct latch_tree_ops bpf_tree_ops = { 627 .less = bpf_tree_less, 628 .comp = bpf_tree_comp, 629 }; 630 631 static DEFINE_SPINLOCK(bpf_lock); 632 static LIST_HEAD(bpf_kallsyms); 633 static struct latch_tree_root bpf_tree __cacheline_aligned; 634 635 void bpf_ksym_add(struct bpf_ksym *ksym) 636 { 637 spin_lock_bh(&bpf_lock); 638 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 639 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 640 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 641 spin_unlock_bh(&bpf_lock); 642 } 643 644 static void __bpf_ksym_del(struct bpf_ksym *ksym) 645 { 646 if (list_empty(&ksym->lnode)) 647 return; 648 649 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 650 list_del_rcu(&ksym->lnode); 651 } 652 653 void bpf_ksym_del(struct bpf_ksym *ksym) 654 { 655 spin_lock_bh(&bpf_lock); 656 __bpf_ksym_del(ksym); 657 spin_unlock_bh(&bpf_lock); 658 } 659 660 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 661 { 662 return fp->jited && !bpf_prog_was_classic(fp); 663 } 664 665 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 666 { 667 if (!bpf_prog_kallsyms_candidate(fp) || 668 !bpf_token_capable(fp->aux->token, CAP_BPF)) 669 return; 670 671 bpf_prog_ksym_set_addr(fp); 672 bpf_prog_ksym_set_name(fp); 673 fp->aux->ksym.prog = true; 674 675 bpf_ksym_add(&fp->aux->ksym); 676 677 #ifdef CONFIG_FINEIBT 678 /* 679 * When FineIBT, code in the __cfi_foo() symbols can get executed 680 * and hence unwinder needs help. 681 */ 682 if (cfi_mode != CFI_FINEIBT) 683 return; 684 685 snprintf(fp->aux->ksym_prefix.name, KSYM_NAME_LEN, 686 "__cfi_%s", fp->aux->ksym.name); 687 688 fp->aux->ksym_prefix.start = (unsigned long) fp->bpf_func - 16; 689 fp->aux->ksym_prefix.end = (unsigned long) fp->bpf_func; 690 691 bpf_ksym_add(&fp->aux->ksym_prefix); 692 #endif 693 } 694 695 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 696 { 697 if (!bpf_prog_kallsyms_candidate(fp)) 698 return; 699 700 bpf_ksym_del(&fp->aux->ksym); 701 #ifdef CONFIG_FINEIBT 702 if (cfi_mode != CFI_FINEIBT) 703 return; 704 bpf_ksym_del(&fp->aux->ksym_prefix); 705 #endif 706 } 707 708 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 709 { 710 struct latch_tree_node *n; 711 712 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 713 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 714 } 715 716 int __bpf_address_lookup(unsigned long addr, unsigned long *size, 717 unsigned long *off, char *sym) 718 { 719 struct bpf_ksym *ksym; 720 int ret = 0; 721 722 rcu_read_lock(); 723 ksym = bpf_ksym_find(addr); 724 if (ksym) { 725 unsigned long symbol_start = ksym->start; 726 unsigned long symbol_end = ksym->end; 727 728 ret = strscpy(sym, ksym->name, KSYM_NAME_LEN); 729 730 if (size) 731 *size = symbol_end - symbol_start; 732 if (off) 733 *off = addr - symbol_start; 734 } 735 rcu_read_unlock(); 736 737 return ret; 738 } 739 740 bool is_bpf_text_address(unsigned long addr) 741 { 742 bool ret; 743 744 rcu_read_lock(); 745 ret = bpf_ksym_find(addr) != NULL; 746 rcu_read_unlock(); 747 748 return ret; 749 } 750 751 struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 752 { 753 struct bpf_ksym *ksym; 754 755 WARN_ON_ONCE(!rcu_read_lock_held()); 756 ksym = bpf_ksym_find(addr); 757 758 return ksym && ksym->prog ? 759 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 760 NULL; 761 } 762 763 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 764 { 765 const struct exception_table_entry *e = NULL; 766 struct bpf_prog *prog; 767 768 rcu_read_lock(); 769 prog = bpf_prog_ksym_find(addr); 770 if (!prog) 771 goto out; 772 if (!prog->aux->num_exentries) 773 goto out; 774 775 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 776 out: 777 rcu_read_unlock(); 778 return e; 779 } 780 781 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 782 char *sym) 783 { 784 struct bpf_ksym *ksym; 785 unsigned int it = 0; 786 int ret = -ERANGE; 787 788 if (!bpf_jit_kallsyms_enabled()) 789 return ret; 790 791 rcu_read_lock(); 792 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 793 if (it++ != symnum) 794 continue; 795 796 strscpy(sym, ksym->name, KSYM_NAME_LEN); 797 798 *value = ksym->start; 799 *type = BPF_SYM_ELF_TYPE; 800 801 ret = 0; 802 break; 803 } 804 rcu_read_unlock(); 805 806 return ret; 807 } 808 809 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 810 struct bpf_jit_poke_descriptor *poke) 811 { 812 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 813 static const u32 poke_tab_max = 1024; 814 u32 slot = prog->aux->size_poke_tab; 815 u32 size = slot + 1; 816 817 if (size > poke_tab_max) 818 return -ENOSPC; 819 if (poke->tailcall_target || poke->tailcall_target_stable || 820 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 821 return -EINVAL; 822 823 switch (poke->reason) { 824 case BPF_POKE_REASON_TAIL_CALL: 825 if (!poke->tail_call.map) 826 return -EINVAL; 827 break; 828 default: 829 return -EINVAL; 830 } 831 832 tab = krealloc_array(tab, size, sizeof(*poke), GFP_KERNEL); 833 if (!tab) 834 return -ENOMEM; 835 836 memcpy(&tab[slot], poke, sizeof(*poke)); 837 prog->aux->size_poke_tab = size; 838 prog->aux->poke_tab = tab; 839 840 return slot; 841 } 842 843 /* 844 * BPF program pack allocator. 845 * 846 * Most BPF programs are pretty small. Allocating a hole page for each 847 * program is sometime a waste. Many small bpf program also adds pressure 848 * to instruction TLB. To solve this issue, we introduce a BPF program pack 849 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 850 * to host BPF programs. 851 */ 852 #define BPF_PROG_CHUNK_SHIFT 6 853 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 854 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 855 856 struct bpf_prog_pack { 857 struct list_head list; 858 void *ptr; 859 unsigned long bitmap[]; 860 }; 861 862 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) 863 { 864 memset(area, 0, size); 865 } 866 867 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 868 869 static DEFINE_MUTEX(pack_mutex); 870 static LIST_HEAD(pack_list); 871 872 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 873 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 874 */ 875 #ifdef PMD_SIZE 876 /* PMD_SIZE is really big for some archs. It doesn't make sense to 877 * reserve too much memory in one allocation. Hardcode BPF_PROG_PACK_SIZE to 878 * 2MiB * num_possible_nodes(). On most architectures PMD_SIZE will be 879 * greater than or equal to 2MB. 880 */ 881 #define BPF_PROG_PACK_SIZE (SZ_2M * num_possible_nodes()) 882 #else 883 #define BPF_PROG_PACK_SIZE PAGE_SIZE 884 #endif 885 886 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 887 888 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 889 { 890 struct bpf_prog_pack *pack; 891 int err; 892 893 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), 894 GFP_KERNEL); 895 if (!pack) 896 return NULL; 897 pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE); 898 if (!pack->ptr) 899 goto out; 900 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 901 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 902 903 set_vm_flush_reset_perms(pack->ptr); 904 err = set_memory_rox((unsigned long)pack->ptr, 905 BPF_PROG_PACK_SIZE / PAGE_SIZE); 906 if (err) 907 goto out; 908 list_add_tail(&pack->list, &pack_list); 909 return pack; 910 911 out: 912 bpf_jit_free_exec(pack->ptr); 913 kfree(pack); 914 return NULL; 915 } 916 917 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 918 { 919 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 920 struct bpf_prog_pack *pack; 921 unsigned long pos; 922 void *ptr = NULL; 923 924 mutex_lock(&pack_mutex); 925 if (size > BPF_PROG_PACK_SIZE) { 926 size = round_up(size, PAGE_SIZE); 927 ptr = bpf_jit_alloc_exec(size); 928 if (ptr) { 929 int err; 930 931 bpf_fill_ill_insns(ptr, size); 932 set_vm_flush_reset_perms(ptr); 933 err = set_memory_rox((unsigned long)ptr, 934 size / PAGE_SIZE); 935 if (err) { 936 bpf_jit_free_exec(ptr); 937 ptr = NULL; 938 } 939 } 940 goto out; 941 } 942 list_for_each_entry(pack, &pack_list, list) { 943 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 944 nbits, 0); 945 if (pos < BPF_PROG_CHUNK_COUNT) 946 goto found_free_area; 947 } 948 949 pack = alloc_new_pack(bpf_fill_ill_insns); 950 if (!pack) 951 goto out; 952 953 pos = 0; 954 955 found_free_area: 956 bitmap_set(pack->bitmap, pos, nbits); 957 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 958 959 out: 960 mutex_unlock(&pack_mutex); 961 return ptr; 962 } 963 964 void bpf_prog_pack_free(void *ptr, u32 size) 965 { 966 struct bpf_prog_pack *pack = NULL, *tmp; 967 unsigned int nbits; 968 unsigned long pos; 969 970 mutex_lock(&pack_mutex); 971 if (size > BPF_PROG_PACK_SIZE) { 972 bpf_jit_free_exec(ptr); 973 goto out; 974 } 975 976 list_for_each_entry(tmp, &pack_list, list) { 977 if (ptr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > ptr) { 978 pack = tmp; 979 break; 980 } 981 } 982 983 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 984 goto out; 985 986 nbits = BPF_PROG_SIZE_TO_NBITS(size); 987 pos = ((unsigned long)ptr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; 988 989 WARN_ONCE(bpf_arch_text_invalidate(ptr, size), 990 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 991 992 bitmap_clear(pack->bitmap, pos, nbits); 993 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 994 BPF_PROG_CHUNK_COUNT, 0) == 0) { 995 list_del(&pack->list); 996 bpf_jit_free_exec(pack->ptr); 997 kfree(pack); 998 } 999 out: 1000 mutex_unlock(&pack_mutex); 1001 } 1002 1003 static atomic_long_t bpf_jit_current; 1004 1005 /* Can be overridden by an arch's JIT compiler if it has a custom, 1006 * dedicated BPF backend memory area, or if neither of the two 1007 * below apply. 1008 */ 1009 u64 __weak bpf_jit_alloc_exec_limit(void) 1010 { 1011 #if defined(MODULES_VADDR) 1012 return MODULES_END - MODULES_VADDR; 1013 #else 1014 return VMALLOC_END - VMALLOC_START; 1015 #endif 1016 } 1017 1018 static int __init bpf_jit_charge_init(void) 1019 { 1020 /* Only used as heuristic here to derive limit. */ 1021 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 1022 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1, 1023 PAGE_SIZE), LONG_MAX); 1024 return 0; 1025 } 1026 pure_initcall(bpf_jit_charge_init); 1027 1028 int bpf_jit_charge_modmem(u32 size) 1029 { 1030 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { 1031 if (!bpf_capable()) { 1032 atomic_long_sub(size, &bpf_jit_current); 1033 return -EPERM; 1034 } 1035 } 1036 1037 return 0; 1038 } 1039 1040 void bpf_jit_uncharge_modmem(u32 size) 1041 { 1042 atomic_long_sub(size, &bpf_jit_current); 1043 } 1044 1045 void *__weak bpf_jit_alloc_exec(unsigned long size) 1046 { 1047 return execmem_alloc(EXECMEM_BPF, size); 1048 } 1049 1050 void __weak bpf_jit_free_exec(void *addr) 1051 { 1052 execmem_free(addr); 1053 } 1054 1055 struct bpf_binary_header * 1056 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1057 unsigned int alignment, 1058 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1059 { 1060 struct bpf_binary_header *hdr; 1061 u32 size, hole, start; 1062 1063 WARN_ON_ONCE(!is_power_of_2(alignment) || 1064 alignment > BPF_IMAGE_ALIGNMENT); 1065 1066 /* Most of BPF filters are really small, but if some of them 1067 * fill a page, allow at least 128 extra bytes to insert a 1068 * random section of illegal instructions. 1069 */ 1070 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1071 1072 if (bpf_jit_charge_modmem(size)) 1073 return NULL; 1074 hdr = bpf_jit_alloc_exec(size); 1075 if (!hdr) { 1076 bpf_jit_uncharge_modmem(size); 1077 return NULL; 1078 } 1079 1080 /* Fill space with illegal/arch-dep instructions. */ 1081 bpf_fill_ill_insns(hdr, size); 1082 1083 hdr->size = size; 1084 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1085 PAGE_SIZE - sizeof(*hdr)); 1086 start = get_random_u32_below(hole) & ~(alignment - 1); 1087 1088 /* Leave a random number of instructions before BPF code. */ 1089 *image_ptr = &hdr->image[start]; 1090 1091 return hdr; 1092 } 1093 1094 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1095 { 1096 u32 size = hdr->size; 1097 1098 bpf_jit_free_exec(hdr); 1099 bpf_jit_uncharge_modmem(size); 1100 } 1101 1102 /* Allocate jit binary from bpf_prog_pack allocator. 1103 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1104 * to the memory. To solve this problem, a RW buffer is also allocated at 1105 * as the same time. The JIT engine should calculate offsets based on the 1106 * RO memory address, but write JITed program to the RW buffer. Once the 1107 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1108 * the JITed program to the RO memory. 1109 */ 1110 struct bpf_binary_header * 1111 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1112 unsigned int alignment, 1113 struct bpf_binary_header **rw_header, 1114 u8 **rw_image, 1115 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1116 { 1117 struct bpf_binary_header *ro_header; 1118 u32 size, hole, start; 1119 1120 WARN_ON_ONCE(!is_power_of_2(alignment) || 1121 alignment > BPF_IMAGE_ALIGNMENT); 1122 1123 /* add 16 bytes for a random section of illegal instructions */ 1124 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1125 1126 if (bpf_jit_charge_modmem(size)) 1127 return NULL; 1128 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1129 if (!ro_header) { 1130 bpf_jit_uncharge_modmem(size); 1131 return NULL; 1132 } 1133 1134 *rw_header = kvmalloc(size, GFP_KERNEL); 1135 if (!*rw_header) { 1136 bpf_prog_pack_free(ro_header, size); 1137 bpf_jit_uncharge_modmem(size); 1138 return NULL; 1139 } 1140 1141 /* Fill space with illegal/arch-dep instructions. */ 1142 bpf_fill_ill_insns(*rw_header, size); 1143 (*rw_header)->size = size; 1144 1145 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1146 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1147 start = get_random_u32_below(hole) & ~(alignment - 1); 1148 1149 *image_ptr = &ro_header->image[start]; 1150 *rw_image = &(*rw_header)->image[start]; 1151 1152 return ro_header; 1153 } 1154 1155 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1156 int bpf_jit_binary_pack_finalize(struct bpf_binary_header *ro_header, 1157 struct bpf_binary_header *rw_header) 1158 { 1159 void *ptr; 1160 1161 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1162 1163 kvfree(rw_header); 1164 1165 if (IS_ERR(ptr)) { 1166 bpf_prog_pack_free(ro_header, ro_header->size); 1167 return PTR_ERR(ptr); 1168 } 1169 return 0; 1170 } 1171 1172 /* bpf_jit_binary_pack_free is called in two different scenarios: 1173 * 1) when the program is freed after; 1174 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1175 * For case 2), we need to free both the RO memory and the RW buffer. 1176 * 1177 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1178 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1179 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1180 * bpf_arch_text_copy (when jit fails). 1181 */ 1182 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1183 struct bpf_binary_header *rw_header) 1184 { 1185 u32 size = ro_header->size; 1186 1187 bpf_prog_pack_free(ro_header, size); 1188 kvfree(rw_header); 1189 bpf_jit_uncharge_modmem(size); 1190 } 1191 1192 struct bpf_binary_header * 1193 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp) 1194 { 1195 unsigned long real_start = (unsigned long)fp->bpf_func; 1196 unsigned long addr; 1197 1198 addr = real_start & BPF_PROG_CHUNK_MASK; 1199 return (void *)addr; 1200 } 1201 1202 static inline struct bpf_binary_header * 1203 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1204 { 1205 unsigned long real_start = (unsigned long)fp->bpf_func; 1206 unsigned long addr; 1207 1208 addr = real_start & PAGE_MASK; 1209 return (void *)addr; 1210 } 1211 1212 /* This symbol is only overridden by archs that have different 1213 * requirements than the usual eBPF JITs, f.e. when they only 1214 * implement cBPF JIT, do not set images read-only, etc. 1215 */ 1216 void __weak bpf_jit_free(struct bpf_prog *fp) 1217 { 1218 if (fp->jited) { 1219 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1220 1221 bpf_jit_binary_free(hdr); 1222 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1223 } 1224 1225 bpf_prog_unlock_free(fp); 1226 } 1227 1228 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1229 const struct bpf_insn *insn, bool extra_pass, 1230 u64 *func_addr, bool *func_addr_fixed) 1231 { 1232 s16 off = insn->off; 1233 s32 imm = insn->imm; 1234 u8 *addr; 1235 int err; 1236 1237 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1238 if (!*func_addr_fixed) { 1239 /* Place-holder address till the last pass has collected 1240 * all addresses for JITed subprograms in which case we 1241 * can pick them up from prog->aux. 1242 */ 1243 if (!extra_pass) 1244 addr = NULL; 1245 else if (prog->aux->func && 1246 off >= 0 && off < prog->aux->real_func_cnt) 1247 addr = (u8 *)prog->aux->func[off]->bpf_func; 1248 else 1249 return -EINVAL; 1250 } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && 1251 bpf_jit_supports_far_kfunc_call()) { 1252 err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr); 1253 if (err) 1254 return err; 1255 } else { 1256 /* Address of a BPF helper call. Since part of the core 1257 * kernel, it's always at a fixed location. __bpf_call_base 1258 * and the helper with imm relative to it are both in core 1259 * kernel. 1260 */ 1261 addr = (u8 *)__bpf_call_base + imm; 1262 } 1263 1264 *func_addr = (unsigned long)addr; 1265 return 0; 1266 } 1267 1268 const char *bpf_jit_get_prog_name(struct bpf_prog *prog) 1269 { 1270 if (prog->aux->ksym.prog) 1271 return prog->aux->ksym.name; 1272 return prog->aux->name; 1273 } 1274 1275 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1276 const struct bpf_insn *aux, 1277 struct bpf_insn *to_buff, 1278 bool emit_zext) 1279 { 1280 struct bpf_insn *to = to_buff; 1281 u32 imm_rnd = get_random_u32(); 1282 s16 off; 1283 1284 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1285 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1286 1287 /* Constraints on AX register: 1288 * 1289 * AX register is inaccessible from user space. It is mapped in 1290 * all JITs, and used here for constant blinding rewrites. It is 1291 * typically "stateless" meaning its contents are only valid within 1292 * the executed instruction, but not across several instructions. 1293 * There are a few exceptions however which are further detailed 1294 * below. 1295 * 1296 * Constant blinding is only used by JITs, not in the interpreter. 1297 * The interpreter uses AX in some occasions as a local temporary 1298 * register e.g. in DIV or MOD instructions. 1299 * 1300 * In restricted circumstances, the verifier can also use the AX 1301 * register for rewrites as long as they do not interfere with 1302 * the above cases! 1303 */ 1304 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1305 goto out; 1306 1307 if (from->imm == 0 && 1308 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1309 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1310 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1311 goto out; 1312 } 1313 1314 switch (from->code) { 1315 case BPF_ALU | BPF_ADD | BPF_K: 1316 case BPF_ALU | BPF_SUB | BPF_K: 1317 case BPF_ALU | BPF_AND | BPF_K: 1318 case BPF_ALU | BPF_OR | BPF_K: 1319 case BPF_ALU | BPF_XOR | BPF_K: 1320 case BPF_ALU | BPF_MUL | BPF_K: 1321 case BPF_ALU | BPF_MOV | BPF_K: 1322 case BPF_ALU | BPF_DIV | BPF_K: 1323 case BPF_ALU | BPF_MOD | BPF_K: 1324 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1325 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1326 *to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off); 1327 break; 1328 1329 case BPF_ALU64 | BPF_ADD | BPF_K: 1330 case BPF_ALU64 | BPF_SUB | BPF_K: 1331 case BPF_ALU64 | BPF_AND | BPF_K: 1332 case BPF_ALU64 | BPF_OR | BPF_K: 1333 case BPF_ALU64 | BPF_XOR | BPF_K: 1334 case BPF_ALU64 | BPF_MUL | BPF_K: 1335 case BPF_ALU64 | BPF_MOV | BPF_K: 1336 case BPF_ALU64 | BPF_DIV | BPF_K: 1337 case BPF_ALU64 | BPF_MOD | BPF_K: 1338 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1339 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1340 *to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off); 1341 break; 1342 1343 case BPF_JMP | BPF_JEQ | BPF_K: 1344 case BPF_JMP | BPF_JNE | BPF_K: 1345 case BPF_JMP | BPF_JGT | BPF_K: 1346 case BPF_JMP | BPF_JLT | BPF_K: 1347 case BPF_JMP | BPF_JGE | BPF_K: 1348 case BPF_JMP | BPF_JLE | BPF_K: 1349 case BPF_JMP | BPF_JSGT | BPF_K: 1350 case BPF_JMP | BPF_JSLT | BPF_K: 1351 case BPF_JMP | BPF_JSGE | BPF_K: 1352 case BPF_JMP | BPF_JSLE | BPF_K: 1353 case BPF_JMP | BPF_JSET | BPF_K: 1354 /* Accommodate for extra offset in case of a backjump. */ 1355 off = from->off; 1356 if (off < 0) 1357 off -= 2; 1358 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1359 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1360 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1361 break; 1362 1363 case BPF_JMP32 | BPF_JEQ | BPF_K: 1364 case BPF_JMP32 | BPF_JNE | BPF_K: 1365 case BPF_JMP32 | BPF_JGT | BPF_K: 1366 case BPF_JMP32 | BPF_JLT | BPF_K: 1367 case BPF_JMP32 | BPF_JGE | BPF_K: 1368 case BPF_JMP32 | BPF_JLE | BPF_K: 1369 case BPF_JMP32 | BPF_JSGT | BPF_K: 1370 case BPF_JMP32 | BPF_JSLT | BPF_K: 1371 case BPF_JMP32 | BPF_JSGE | BPF_K: 1372 case BPF_JMP32 | BPF_JSLE | BPF_K: 1373 case BPF_JMP32 | BPF_JSET | BPF_K: 1374 /* Accommodate for extra offset in case of a backjump. */ 1375 off = from->off; 1376 if (off < 0) 1377 off -= 2; 1378 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1379 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1380 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1381 off); 1382 break; 1383 1384 case BPF_LD | BPF_IMM | BPF_DW: 1385 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1386 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1387 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1388 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1389 break; 1390 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1391 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1392 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1393 if (emit_zext) 1394 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1395 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1396 break; 1397 1398 case BPF_ST | BPF_MEM | BPF_DW: 1399 case BPF_ST | BPF_MEM | BPF_W: 1400 case BPF_ST | BPF_MEM | BPF_H: 1401 case BPF_ST | BPF_MEM | BPF_B: 1402 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1403 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1404 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1405 break; 1406 } 1407 out: 1408 return to - to_buff; 1409 } 1410 1411 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1412 gfp_t gfp_extra_flags) 1413 { 1414 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1415 struct bpf_prog *fp; 1416 1417 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1418 if (fp != NULL) { 1419 /* aux->prog still points to the fp_other one, so 1420 * when promoting the clone to the real program, 1421 * this still needs to be adapted. 1422 */ 1423 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1424 } 1425 1426 return fp; 1427 } 1428 1429 static void bpf_prog_clone_free(struct bpf_prog *fp) 1430 { 1431 /* aux was stolen by the other clone, so we cannot free 1432 * it from this path! It will be freed eventually by the 1433 * other program on release. 1434 * 1435 * At this point, we don't need a deferred release since 1436 * clone is guaranteed to not be locked. 1437 */ 1438 fp->aux = NULL; 1439 fp->stats = NULL; 1440 fp->active = NULL; 1441 __bpf_prog_free(fp); 1442 } 1443 1444 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1445 { 1446 /* We have to repoint aux->prog to self, as we don't 1447 * know whether fp here is the clone or the original. 1448 */ 1449 fp->aux->prog = fp; 1450 bpf_prog_clone_free(fp_other); 1451 } 1452 1453 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1454 { 1455 struct bpf_insn insn_buff[16], aux[2]; 1456 struct bpf_prog *clone, *tmp; 1457 int insn_delta, insn_cnt; 1458 struct bpf_insn *insn; 1459 int i, rewritten; 1460 1461 if (!prog->blinding_requested || prog->blinded) 1462 return prog; 1463 1464 clone = bpf_prog_clone_create(prog, GFP_USER); 1465 if (!clone) 1466 return ERR_PTR(-ENOMEM); 1467 1468 insn_cnt = clone->len; 1469 insn = clone->insnsi; 1470 1471 for (i = 0; i < insn_cnt; i++, insn++) { 1472 if (bpf_pseudo_func(insn)) { 1473 /* ld_imm64 with an address of bpf subprog is not 1474 * a user controlled constant. Don't randomize it, 1475 * since it will conflict with jit_subprogs() logic. 1476 */ 1477 insn++; 1478 i++; 1479 continue; 1480 } 1481 1482 /* We temporarily need to hold the original ld64 insn 1483 * so that we can still access the first part in the 1484 * second blinding run. 1485 */ 1486 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1487 insn[1].code == 0) 1488 memcpy(aux, insn, sizeof(aux)); 1489 1490 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1491 clone->aux->verifier_zext); 1492 if (!rewritten) 1493 continue; 1494 1495 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1496 if (IS_ERR(tmp)) { 1497 /* Patching may have repointed aux->prog during 1498 * realloc from the original one, so we need to 1499 * fix it up here on error. 1500 */ 1501 bpf_jit_prog_release_other(prog, clone); 1502 return tmp; 1503 } 1504 1505 clone = tmp; 1506 insn_delta = rewritten - 1; 1507 1508 /* Walk new program and skip insns we just inserted. */ 1509 insn = clone->insnsi + i + insn_delta; 1510 insn_cnt += insn_delta; 1511 i += insn_delta; 1512 } 1513 1514 clone->blinded = 1; 1515 return clone; 1516 } 1517 #endif /* CONFIG_BPF_JIT */ 1518 1519 /* Base function for offset calculation. Needs to go into .text section, 1520 * therefore keeping it non-static as well; will also be used by JITs 1521 * anyway later on, so do not let the compiler omit it. This also needs 1522 * to go into kallsyms for correlation from e.g. bpftool, so naming 1523 * must not change. 1524 */ 1525 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1526 { 1527 return 0; 1528 } 1529 EXPORT_SYMBOL_GPL(__bpf_call_base); 1530 1531 /* All UAPI available opcodes. */ 1532 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1533 /* 32 bit ALU operations. */ \ 1534 /* Register based. */ \ 1535 INSN_3(ALU, ADD, X), \ 1536 INSN_3(ALU, SUB, X), \ 1537 INSN_3(ALU, AND, X), \ 1538 INSN_3(ALU, OR, X), \ 1539 INSN_3(ALU, LSH, X), \ 1540 INSN_3(ALU, RSH, X), \ 1541 INSN_3(ALU, XOR, X), \ 1542 INSN_3(ALU, MUL, X), \ 1543 INSN_3(ALU, MOV, X), \ 1544 INSN_3(ALU, ARSH, X), \ 1545 INSN_3(ALU, DIV, X), \ 1546 INSN_3(ALU, MOD, X), \ 1547 INSN_2(ALU, NEG), \ 1548 INSN_3(ALU, END, TO_BE), \ 1549 INSN_3(ALU, END, TO_LE), \ 1550 /* Immediate based. */ \ 1551 INSN_3(ALU, ADD, K), \ 1552 INSN_3(ALU, SUB, K), \ 1553 INSN_3(ALU, AND, K), \ 1554 INSN_3(ALU, OR, K), \ 1555 INSN_3(ALU, LSH, K), \ 1556 INSN_3(ALU, RSH, K), \ 1557 INSN_3(ALU, XOR, K), \ 1558 INSN_3(ALU, MUL, K), \ 1559 INSN_3(ALU, MOV, K), \ 1560 INSN_3(ALU, ARSH, K), \ 1561 INSN_3(ALU, DIV, K), \ 1562 INSN_3(ALU, MOD, K), \ 1563 /* 64 bit ALU operations. */ \ 1564 /* Register based. */ \ 1565 INSN_3(ALU64, ADD, X), \ 1566 INSN_3(ALU64, SUB, X), \ 1567 INSN_3(ALU64, AND, X), \ 1568 INSN_3(ALU64, OR, X), \ 1569 INSN_3(ALU64, LSH, X), \ 1570 INSN_3(ALU64, RSH, X), \ 1571 INSN_3(ALU64, XOR, X), \ 1572 INSN_3(ALU64, MUL, X), \ 1573 INSN_3(ALU64, MOV, X), \ 1574 INSN_3(ALU64, ARSH, X), \ 1575 INSN_3(ALU64, DIV, X), \ 1576 INSN_3(ALU64, MOD, X), \ 1577 INSN_2(ALU64, NEG), \ 1578 INSN_3(ALU64, END, TO_LE), \ 1579 /* Immediate based. */ \ 1580 INSN_3(ALU64, ADD, K), \ 1581 INSN_3(ALU64, SUB, K), \ 1582 INSN_3(ALU64, AND, K), \ 1583 INSN_3(ALU64, OR, K), \ 1584 INSN_3(ALU64, LSH, K), \ 1585 INSN_3(ALU64, RSH, K), \ 1586 INSN_3(ALU64, XOR, K), \ 1587 INSN_3(ALU64, MUL, K), \ 1588 INSN_3(ALU64, MOV, K), \ 1589 INSN_3(ALU64, ARSH, K), \ 1590 INSN_3(ALU64, DIV, K), \ 1591 INSN_3(ALU64, MOD, K), \ 1592 /* Call instruction. */ \ 1593 INSN_2(JMP, CALL), \ 1594 /* Exit instruction. */ \ 1595 INSN_2(JMP, EXIT), \ 1596 /* 32-bit Jump instructions. */ \ 1597 /* Register based. */ \ 1598 INSN_3(JMP32, JEQ, X), \ 1599 INSN_3(JMP32, JNE, X), \ 1600 INSN_3(JMP32, JGT, X), \ 1601 INSN_3(JMP32, JLT, X), \ 1602 INSN_3(JMP32, JGE, X), \ 1603 INSN_3(JMP32, JLE, X), \ 1604 INSN_3(JMP32, JSGT, X), \ 1605 INSN_3(JMP32, JSLT, X), \ 1606 INSN_3(JMP32, JSGE, X), \ 1607 INSN_3(JMP32, JSLE, X), \ 1608 INSN_3(JMP32, JSET, X), \ 1609 /* Immediate based. */ \ 1610 INSN_3(JMP32, JEQ, K), \ 1611 INSN_3(JMP32, JNE, K), \ 1612 INSN_3(JMP32, JGT, K), \ 1613 INSN_3(JMP32, JLT, K), \ 1614 INSN_3(JMP32, JGE, K), \ 1615 INSN_3(JMP32, JLE, K), \ 1616 INSN_3(JMP32, JSGT, K), \ 1617 INSN_3(JMP32, JSLT, K), \ 1618 INSN_3(JMP32, JSGE, K), \ 1619 INSN_3(JMP32, JSLE, K), \ 1620 INSN_3(JMP32, JSET, K), \ 1621 /* Jump instructions. */ \ 1622 /* Register based. */ \ 1623 INSN_3(JMP, JEQ, X), \ 1624 INSN_3(JMP, JNE, X), \ 1625 INSN_3(JMP, JGT, X), \ 1626 INSN_3(JMP, JLT, X), \ 1627 INSN_3(JMP, JGE, X), \ 1628 INSN_3(JMP, JLE, X), \ 1629 INSN_3(JMP, JSGT, X), \ 1630 INSN_3(JMP, JSLT, X), \ 1631 INSN_3(JMP, JSGE, X), \ 1632 INSN_3(JMP, JSLE, X), \ 1633 INSN_3(JMP, JSET, X), \ 1634 /* Immediate based. */ \ 1635 INSN_3(JMP, JEQ, K), \ 1636 INSN_3(JMP, JNE, K), \ 1637 INSN_3(JMP, JGT, K), \ 1638 INSN_3(JMP, JLT, K), \ 1639 INSN_3(JMP, JGE, K), \ 1640 INSN_3(JMP, JLE, K), \ 1641 INSN_3(JMP, JSGT, K), \ 1642 INSN_3(JMP, JSLT, K), \ 1643 INSN_3(JMP, JSGE, K), \ 1644 INSN_3(JMP, JSLE, K), \ 1645 INSN_3(JMP, JSET, K), \ 1646 INSN_2(JMP, JA), \ 1647 INSN_2(JMP32, JA), \ 1648 /* Atomic operations. */ \ 1649 INSN_3(STX, ATOMIC, B), \ 1650 INSN_3(STX, ATOMIC, H), \ 1651 INSN_3(STX, ATOMIC, W), \ 1652 INSN_3(STX, ATOMIC, DW), \ 1653 /* Store instructions. */ \ 1654 /* Register based. */ \ 1655 INSN_3(STX, MEM, B), \ 1656 INSN_3(STX, MEM, H), \ 1657 INSN_3(STX, MEM, W), \ 1658 INSN_3(STX, MEM, DW), \ 1659 /* Immediate based. */ \ 1660 INSN_3(ST, MEM, B), \ 1661 INSN_3(ST, MEM, H), \ 1662 INSN_3(ST, MEM, W), \ 1663 INSN_3(ST, MEM, DW), \ 1664 /* Load instructions. */ \ 1665 /* Register based. */ \ 1666 INSN_3(LDX, MEM, B), \ 1667 INSN_3(LDX, MEM, H), \ 1668 INSN_3(LDX, MEM, W), \ 1669 INSN_3(LDX, MEM, DW), \ 1670 INSN_3(LDX, MEMSX, B), \ 1671 INSN_3(LDX, MEMSX, H), \ 1672 INSN_3(LDX, MEMSX, W), \ 1673 /* Immediate based. */ \ 1674 INSN_3(LD, IMM, DW) 1675 1676 bool bpf_opcode_in_insntable(u8 code) 1677 { 1678 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1679 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1680 static const bool public_insntable[256] = { 1681 [0 ... 255] = false, 1682 /* Now overwrite non-defaults ... */ 1683 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1684 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1685 [BPF_LD | BPF_ABS | BPF_B] = true, 1686 [BPF_LD | BPF_ABS | BPF_H] = true, 1687 [BPF_LD | BPF_ABS | BPF_W] = true, 1688 [BPF_LD | BPF_IND | BPF_B] = true, 1689 [BPF_LD | BPF_IND | BPF_H] = true, 1690 [BPF_LD | BPF_IND | BPF_W] = true, 1691 [BPF_JMP | BPF_JCOND] = true, 1692 }; 1693 #undef BPF_INSN_3_TBL 1694 #undef BPF_INSN_2_TBL 1695 return public_insntable[code]; 1696 } 1697 1698 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1699 /** 1700 * ___bpf_prog_run - run eBPF program on a given context 1701 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1702 * @insn: is the array of eBPF instructions 1703 * 1704 * Decode and execute eBPF instructions. 1705 * 1706 * Return: whatever value is in %BPF_R0 at program exit 1707 */ 1708 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1709 { 1710 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1711 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1712 static const void * const jumptable[256] __annotate_jump_table = { 1713 [0 ... 255] = &&default_label, 1714 /* Now overwrite non-defaults ... */ 1715 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1716 /* Non-UAPI available opcodes. */ 1717 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1718 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1719 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1720 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1721 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1722 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1723 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1724 [BPF_LDX | BPF_PROBE_MEMSX | BPF_B] = &&LDX_PROBE_MEMSX_B, 1725 [BPF_LDX | BPF_PROBE_MEMSX | BPF_H] = &&LDX_PROBE_MEMSX_H, 1726 [BPF_LDX | BPF_PROBE_MEMSX | BPF_W] = &&LDX_PROBE_MEMSX_W, 1727 }; 1728 #undef BPF_INSN_3_LBL 1729 #undef BPF_INSN_2_LBL 1730 u32 tail_call_cnt = 0; 1731 1732 #define CONT ({ insn++; goto select_insn; }) 1733 #define CONT_JMP ({ insn++; goto select_insn; }) 1734 1735 select_insn: 1736 goto *jumptable[insn->code]; 1737 1738 /* Explicitly mask the register-based shift amounts with 63 or 31 1739 * to avoid undefined behavior. Normally this won't affect the 1740 * generated code, for example, in case of native 64 bit archs such 1741 * as x86-64 or arm64, the compiler is optimizing the AND away for 1742 * the interpreter. In case of JITs, each of the JIT backends compiles 1743 * the BPF shift operations to machine instructions which produce 1744 * implementation-defined results in such a case; the resulting 1745 * contents of the register may be arbitrary, but program behaviour 1746 * as a whole remains defined. In other words, in case of JIT backends, 1747 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1748 */ 1749 /* ALU (shifts) */ 1750 #define SHT(OPCODE, OP) \ 1751 ALU64_##OPCODE##_X: \ 1752 DST = DST OP (SRC & 63); \ 1753 CONT; \ 1754 ALU_##OPCODE##_X: \ 1755 DST = (u32) DST OP ((u32) SRC & 31); \ 1756 CONT; \ 1757 ALU64_##OPCODE##_K: \ 1758 DST = DST OP IMM; \ 1759 CONT; \ 1760 ALU_##OPCODE##_K: \ 1761 DST = (u32) DST OP (u32) IMM; \ 1762 CONT; 1763 /* ALU (rest) */ 1764 #define ALU(OPCODE, OP) \ 1765 ALU64_##OPCODE##_X: \ 1766 DST = DST OP SRC; \ 1767 CONT; \ 1768 ALU_##OPCODE##_X: \ 1769 DST = (u32) DST OP (u32) SRC; \ 1770 CONT; \ 1771 ALU64_##OPCODE##_K: \ 1772 DST = DST OP IMM; \ 1773 CONT; \ 1774 ALU_##OPCODE##_K: \ 1775 DST = (u32) DST OP (u32) IMM; \ 1776 CONT; 1777 ALU(ADD, +) 1778 ALU(SUB, -) 1779 ALU(AND, &) 1780 ALU(OR, |) 1781 ALU(XOR, ^) 1782 ALU(MUL, *) 1783 SHT(LSH, <<) 1784 SHT(RSH, >>) 1785 #undef SHT 1786 #undef ALU 1787 ALU_NEG: 1788 DST = (u32) -DST; 1789 CONT; 1790 ALU64_NEG: 1791 DST = -DST; 1792 CONT; 1793 ALU_MOV_X: 1794 switch (OFF) { 1795 case 0: 1796 DST = (u32) SRC; 1797 break; 1798 case 8: 1799 DST = (u32)(s8) SRC; 1800 break; 1801 case 16: 1802 DST = (u32)(s16) SRC; 1803 break; 1804 } 1805 CONT; 1806 ALU_MOV_K: 1807 DST = (u32) IMM; 1808 CONT; 1809 ALU64_MOV_X: 1810 switch (OFF) { 1811 case 0: 1812 DST = SRC; 1813 break; 1814 case 8: 1815 DST = (s8) SRC; 1816 break; 1817 case 16: 1818 DST = (s16) SRC; 1819 break; 1820 case 32: 1821 DST = (s32) SRC; 1822 break; 1823 } 1824 CONT; 1825 ALU64_MOV_K: 1826 DST = IMM; 1827 CONT; 1828 LD_IMM_DW: 1829 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1830 insn++; 1831 CONT; 1832 ALU_ARSH_X: 1833 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1834 CONT; 1835 ALU_ARSH_K: 1836 DST = (u64) (u32) (((s32) DST) >> IMM); 1837 CONT; 1838 ALU64_ARSH_X: 1839 (*(s64 *) &DST) >>= (SRC & 63); 1840 CONT; 1841 ALU64_ARSH_K: 1842 (*(s64 *) &DST) >>= IMM; 1843 CONT; 1844 ALU64_MOD_X: 1845 switch (OFF) { 1846 case 0: 1847 div64_u64_rem(DST, SRC, &AX); 1848 DST = AX; 1849 break; 1850 case 1: 1851 AX = div64_s64(DST, SRC); 1852 DST = DST - AX * SRC; 1853 break; 1854 } 1855 CONT; 1856 ALU_MOD_X: 1857 switch (OFF) { 1858 case 0: 1859 AX = (u32) DST; 1860 DST = do_div(AX, (u32) SRC); 1861 break; 1862 case 1: 1863 AX = abs((s32)DST); 1864 AX = do_div(AX, abs((s32)SRC)); 1865 if ((s32)DST < 0) 1866 DST = (u32)-AX; 1867 else 1868 DST = (u32)AX; 1869 break; 1870 } 1871 CONT; 1872 ALU64_MOD_K: 1873 switch (OFF) { 1874 case 0: 1875 div64_u64_rem(DST, IMM, &AX); 1876 DST = AX; 1877 break; 1878 case 1: 1879 AX = div64_s64(DST, IMM); 1880 DST = DST - AX * IMM; 1881 break; 1882 } 1883 CONT; 1884 ALU_MOD_K: 1885 switch (OFF) { 1886 case 0: 1887 AX = (u32) DST; 1888 DST = do_div(AX, (u32) IMM); 1889 break; 1890 case 1: 1891 AX = abs((s32)DST); 1892 AX = do_div(AX, abs((s32)IMM)); 1893 if ((s32)DST < 0) 1894 DST = (u32)-AX; 1895 else 1896 DST = (u32)AX; 1897 break; 1898 } 1899 CONT; 1900 ALU64_DIV_X: 1901 switch (OFF) { 1902 case 0: 1903 DST = div64_u64(DST, SRC); 1904 break; 1905 case 1: 1906 DST = div64_s64(DST, SRC); 1907 break; 1908 } 1909 CONT; 1910 ALU_DIV_X: 1911 switch (OFF) { 1912 case 0: 1913 AX = (u32) DST; 1914 do_div(AX, (u32) SRC); 1915 DST = (u32) AX; 1916 break; 1917 case 1: 1918 AX = abs((s32)DST); 1919 do_div(AX, abs((s32)SRC)); 1920 if (((s32)DST < 0) == ((s32)SRC < 0)) 1921 DST = (u32)AX; 1922 else 1923 DST = (u32)-AX; 1924 break; 1925 } 1926 CONT; 1927 ALU64_DIV_K: 1928 switch (OFF) { 1929 case 0: 1930 DST = div64_u64(DST, IMM); 1931 break; 1932 case 1: 1933 DST = div64_s64(DST, IMM); 1934 break; 1935 } 1936 CONT; 1937 ALU_DIV_K: 1938 switch (OFF) { 1939 case 0: 1940 AX = (u32) DST; 1941 do_div(AX, (u32) IMM); 1942 DST = (u32) AX; 1943 break; 1944 case 1: 1945 AX = abs((s32)DST); 1946 do_div(AX, abs((s32)IMM)); 1947 if (((s32)DST < 0) == ((s32)IMM < 0)) 1948 DST = (u32)AX; 1949 else 1950 DST = (u32)-AX; 1951 break; 1952 } 1953 CONT; 1954 ALU_END_TO_BE: 1955 switch (IMM) { 1956 case 16: 1957 DST = (__force u16) cpu_to_be16(DST); 1958 break; 1959 case 32: 1960 DST = (__force u32) cpu_to_be32(DST); 1961 break; 1962 case 64: 1963 DST = (__force u64) cpu_to_be64(DST); 1964 break; 1965 } 1966 CONT; 1967 ALU_END_TO_LE: 1968 switch (IMM) { 1969 case 16: 1970 DST = (__force u16) cpu_to_le16(DST); 1971 break; 1972 case 32: 1973 DST = (__force u32) cpu_to_le32(DST); 1974 break; 1975 case 64: 1976 DST = (__force u64) cpu_to_le64(DST); 1977 break; 1978 } 1979 CONT; 1980 ALU64_END_TO_LE: 1981 switch (IMM) { 1982 case 16: 1983 DST = (__force u16) __swab16(DST); 1984 break; 1985 case 32: 1986 DST = (__force u32) __swab32(DST); 1987 break; 1988 case 64: 1989 DST = (__force u64) __swab64(DST); 1990 break; 1991 } 1992 CONT; 1993 1994 /* CALL */ 1995 JMP_CALL: 1996 /* Function call scratches BPF_R1-BPF_R5 registers, 1997 * preserves BPF_R6-BPF_R9, and stores return value 1998 * into BPF_R0. 1999 */ 2000 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 2001 BPF_R4, BPF_R5); 2002 CONT; 2003 2004 JMP_CALL_ARGS: 2005 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 2006 BPF_R3, BPF_R4, 2007 BPF_R5, 2008 insn + insn->off + 1); 2009 CONT; 2010 2011 JMP_TAIL_CALL: { 2012 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 2013 struct bpf_array *array = container_of(map, struct bpf_array, map); 2014 struct bpf_prog *prog; 2015 u32 index = BPF_R3; 2016 2017 if (unlikely(index >= array->map.max_entries)) 2018 goto out; 2019 2020 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 2021 goto out; 2022 2023 tail_call_cnt++; 2024 2025 prog = READ_ONCE(array->ptrs[index]); 2026 if (!prog) 2027 goto out; 2028 2029 /* ARG1 at this point is guaranteed to point to CTX from 2030 * the verifier side due to the fact that the tail call is 2031 * handled like a helper, that is, bpf_tail_call_proto, 2032 * where arg1_type is ARG_PTR_TO_CTX. 2033 */ 2034 insn = prog->insnsi; 2035 goto select_insn; 2036 out: 2037 CONT; 2038 } 2039 JMP_JA: 2040 insn += insn->off; 2041 CONT; 2042 JMP32_JA: 2043 insn += insn->imm; 2044 CONT; 2045 JMP_EXIT: 2046 return BPF_R0; 2047 /* JMP */ 2048 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 2049 JMP_##OPCODE##_X: \ 2050 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 2051 insn += insn->off; \ 2052 CONT_JMP; \ 2053 } \ 2054 CONT; \ 2055 JMP32_##OPCODE##_X: \ 2056 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 2057 insn += insn->off; \ 2058 CONT_JMP; \ 2059 } \ 2060 CONT; \ 2061 JMP_##OPCODE##_K: \ 2062 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 2063 insn += insn->off; \ 2064 CONT_JMP; \ 2065 } \ 2066 CONT; \ 2067 JMP32_##OPCODE##_K: \ 2068 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 2069 insn += insn->off; \ 2070 CONT_JMP; \ 2071 } \ 2072 CONT; 2073 COND_JMP(u, JEQ, ==) 2074 COND_JMP(u, JNE, !=) 2075 COND_JMP(u, JGT, >) 2076 COND_JMP(u, JLT, <) 2077 COND_JMP(u, JGE, >=) 2078 COND_JMP(u, JLE, <=) 2079 COND_JMP(u, JSET, &) 2080 COND_JMP(s, JSGT, >) 2081 COND_JMP(s, JSLT, <) 2082 COND_JMP(s, JSGE, >=) 2083 COND_JMP(s, JSLE, <=) 2084 #undef COND_JMP 2085 /* ST, STX and LDX*/ 2086 ST_NOSPEC: 2087 /* Speculation barrier for mitigating Speculative Store Bypass, 2088 * Bounds-Check Bypass and Type Confusion. In case of arm64, we 2089 * rely on the firmware mitigation as controlled via the ssbd 2090 * kernel parameter. Whenever the mitigation is enabled, it 2091 * works for all of the kernel code with no need to provide any 2092 * additional instructions here. In case of x86, we use 'lfence' 2093 * insn for mitigation. We reuse preexisting logic from Spectre 2094 * v1 mitigation that happens to produce the required code on 2095 * x86 for v4 as well. 2096 */ 2097 barrier_nospec(); 2098 CONT; 2099 #define LDST(SIZEOP, SIZE) \ 2100 STX_MEM_##SIZEOP: \ 2101 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 2102 CONT; \ 2103 ST_MEM_##SIZEOP: \ 2104 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 2105 CONT; \ 2106 LDX_MEM_##SIZEOP: \ 2107 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 2108 CONT; \ 2109 LDX_PROBE_MEM_##SIZEOP: \ 2110 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ 2111 (const void *)(long) (SRC + insn->off)); \ 2112 DST = *((SIZE *)&DST); \ 2113 CONT; 2114 2115 LDST(B, u8) 2116 LDST(H, u16) 2117 LDST(W, u32) 2118 LDST(DW, u64) 2119 #undef LDST 2120 2121 #define LDSX(SIZEOP, SIZE) \ 2122 LDX_MEMSX_##SIZEOP: \ 2123 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 2124 CONT; \ 2125 LDX_PROBE_MEMSX_##SIZEOP: \ 2126 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ 2127 (const void *)(long) (SRC + insn->off)); \ 2128 DST = *((SIZE *)&DST); \ 2129 CONT; 2130 2131 LDSX(B, s8) 2132 LDSX(H, s16) 2133 LDSX(W, s32) 2134 #undef LDSX 2135 2136 #define ATOMIC_ALU_OP(BOP, KOP) \ 2137 case BOP: \ 2138 if (BPF_SIZE(insn->code) == BPF_W) \ 2139 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 2140 (DST + insn->off)); \ 2141 else if (BPF_SIZE(insn->code) == BPF_DW) \ 2142 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 2143 (DST + insn->off)); \ 2144 else \ 2145 goto default_label; \ 2146 break; \ 2147 case BOP | BPF_FETCH: \ 2148 if (BPF_SIZE(insn->code) == BPF_W) \ 2149 SRC = (u32) atomic_fetch_##KOP( \ 2150 (u32) SRC, \ 2151 (atomic_t *)(unsigned long) (DST + insn->off)); \ 2152 else if (BPF_SIZE(insn->code) == BPF_DW) \ 2153 SRC = (u64) atomic64_fetch_##KOP( \ 2154 (u64) SRC, \ 2155 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 2156 else \ 2157 goto default_label; \ 2158 break; 2159 2160 STX_ATOMIC_DW: 2161 STX_ATOMIC_W: 2162 STX_ATOMIC_H: 2163 STX_ATOMIC_B: 2164 switch (IMM) { 2165 /* Atomic read-modify-write instructions support only W and DW 2166 * size modifiers. 2167 */ 2168 ATOMIC_ALU_OP(BPF_ADD, add) 2169 ATOMIC_ALU_OP(BPF_AND, and) 2170 ATOMIC_ALU_OP(BPF_OR, or) 2171 ATOMIC_ALU_OP(BPF_XOR, xor) 2172 #undef ATOMIC_ALU_OP 2173 2174 case BPF_XCHG: 2175 if (BPF_SIZE(insn->code) == BPF_W) 2176 SRC = (u32) atomic_xchg( 2177 (atomic_t *)(unsigned long) (DST + insn->off), 2178 (u32) SRC); 2179 else if (BPF_SIZE(insn->code) == BPF_DW) 2180 SRC = (u64) atomic64_xchg( 2181 (atomic64_t *)(unsigned long) (DST + insn->off), 2182 (u64) SRC); 2183 else 2184 goto default_label; 2185 break; 2186 case BPF_CMPXCHG: 2187 if (BPF_SIZE(insn->code) == BPF_W) 2188 BPF_R0 = (u32) atomic_cmpxchg( 2189 (atomic_t *)(unsigned long) (DST + insn->off), 2190 (u32) BPF_R0, (u32) SRC); 2191 else if (BPF_SIZE(insn->code) == BPF_DW) 2192 BPF_R0 = (u64) atomic64_cmpxchg( 2193 (atomic64_t *)(unsigned long) (DST + insn->off), 2194 (u64) BPF_R0, (u64) SRC); 2195 else 2196 goto default_label; 2197 break; 2198 /* Atomic load and store instructions support all size 2199 * modifiers. 2200 */ 2201 case BPF_LOAD_ACQ: 2202 switch (BPF_SIZE(insn->code)) { 2203 #define LOAD_ACQUIRE(SIZEOP, SIZE) \ 2204 case BPF_##SIZEOP: \ 2205 DST = (SIZE)smp_load_acquire( \ 2206 (SIZE *)(unsigned long)(SRC + insn->off)); \ 2207 break; 2208 LOAD_ACQUIRE(B, u8) 2209 LOAD_ACQUIRE(H, u16) 2210 LOAD_ACQUIRE(W, u32) 2211 #ifdef CONFIG_64BIT 2212 LOAD_ACQUIRE(DW, u64) 2213 #endif 2214 #undef LOAD_ACQUIRE 2215 default: 2216 goto default_label; 2217 } 2218 break; 2219 case BPF_STORE_REL: 2220 switch (BPF_SIZE(insn->code)) { 2221 #define STORE_RELEASE(SIZEOP, SIZE) \ 2222 case BPF_##SIZEOP: \ 2223 smp_store_release( \ 2224 (SIZE *)(unsigned long)(DST + insn->off), (SIZE)SRC); \ 2225 break; 2226 STORE_RELEASE(B, u8) 2227 STORE_RELEASE(H, u16) 2228 STORE_RELEASE(W, u32) 2229 #ifdef CONFIG_64BIT 2230 STORE_RELEASE(DW, u64) 2231 #endif 2232 #undef STORE_RELEASE 2233 default: 2234 goto default_label; 2235 } 2236 break; 2237 2238 default: 2239 goto default_label; 2240 } 2241 CONT; 2242 2243 default_label: 2244 /* If we ever reach this, we have a bug somewhere. Die hard here 2245 * instead of just returning 0; we could be somewhere in a subprog, 2246 * so execution could continue otherwise which we do /not/ want. 2247 * 2248 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 2249 */ 2250 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2251 insn->code, insn->imm); 2252 BUG_ON(1); 2253 return 0; 2254 } 2255 2256 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2257 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2258 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2259 { \ 2260 u64 stack[stack_size / sizeof(u64)]; \ 2261 u64 regs[MAX_BPF_EXT_REG] = {}; \ 2262 \ 2263 kmsan_unpoison_memory(stack, sizeof(stack)); \ 2264 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2265 ARG1 = (u64) (unsigned long) ctx; \ 2266 return ___bpf_prog_run(regs, insn); \ 2267 } 2268 2269 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2270 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2271 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2272 const struct bpf_insn *insn) \ 2273 { \ 2274 u64 stack[stack_size / sizeof(u64)]; \ 2275 u64 regs[MAX_BPF_EXT_REG]; \ 2276 \ 2277 kmsan_unpoison_memory(stack, sizeof(stack)); \ 2278 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2279 BPF_R1 = r1; \ 2280 BPF_R2 = r2; \ 2281 BPF_R3 = r3; \ 2282 BPF_R4 = r4; \ 2283 BPF_R5 = r5; \ 2284 return ___bpf_prog_run(regs, insn); \ 2285 } 2286 2287 #define EVAL1(FN, X) FN(X) 2288 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2289 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2290 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2291 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2292 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2293 2294 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2295 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2296 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2297 2298 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2299 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2300 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2301 2302 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2303 2304 static unsigned int (*interpreters[])(const void *ctx, 2305 const struct bpf_insn *insn) = { 2306 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2307 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2308 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2309 }; 2310 #undef PROG_NAME_LIST 2311 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2312 static __maybe_unused 2313 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2314 const struct bpf_insn *insn) = { 2315 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2316 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2317 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2318 }; 2319 #undef PROG_NAME_LIST 2320 2321 #ifdef CONFIG_BPF_SYSCALL 2322 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2323 { 2324 stack_depth = max_t(u32, stack_depth, 1); 2325 insn->off = (s16) insn->imm; 2326 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2327 __bpf_call_base_args; 2328 insn->code = BPF_JMP | BPF_CALL_ARGS; 2329 } 2330 #endif 2331 #endif 2332 2333 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2334 const struct bpf_insn *insn) 2335 { 2336 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2337 * is not working properly, so warn about it! 2338 */ 2339 WARN_ON_ONCE(1); 2340 return 0; 2341 } 2342 2343 static bool __bpf_prog_map_compatible(struct bpf_map *map, 2344 const struct bpf_prog *fp) 2345 { 2346 enum bpf_prog_type prog_type = resolve_prog_type(fp); 2347 struct bpf_prog_aux *aux = fp->aux; 2348 enum bpf_cgroup_storage_type i; 2349 bool ret = false; 2350 u64 cookie; 2351 2352 if (fp->kprobe_override) 2353 return ret; 2354 2355 spin_lock(&map->owner_lock); 2356 /* There's no owner yet where we could check for compatibility. */ 2357 if (!map->owner) { 2358 map->owner = bpf_map_owner_alloc(map); 2359 if (!map->owner) 2360 goto err; 2361 map->owner->type = prog_type; 2362 map->owner->jited = fp->jited; 2363 map->owner->xdp_has_frags = aux->xdp_has_frags; 2364 map->owner->attach_func_proto = aux->attach_func_proto; 2365 for_each_cgroup_storage_type(i) { 2366 map->owner->storage_cookie[i] = 2367 aux->cgroup_storage[i] ? 2368 aux->cgroup_storage[i]->cookie : 0; 2369 } 2370 ret = true; 2371 } else { 2372 ret = map->owner->type == prog_type && 2373 map->owner->jited == fp->jited && 2374 map->owner->xdp_has_frags == aux->xdp_has_frags; 2375 for_each_cgroup_storage_type(i) { 2376 if (!ret) 2377 break; 2378 cookie = aux->cgroup_storage[i] ? 2379 aux->cgroup_storage[i]->cookie : 0; 2380 ret = map->owner->storage_cookie[i] == cookie || 2381 !cookie; 2382 } 2383 if (ret && 2384 map->owner->attach_func_proto != aux->attach_func_proto) { 2385 switch (prog_type) { 2386 case BPF_PROG_TYPE_TRACING: 2387 case BPF_PROG_TYPE_LSM: 2388 case BPF_PROG_TYPE_EXT: 2389 case BPF_PROG_TYPE_STRUCT_OPS: 2390 ret = false; 2391 break; 2392 default: 2393 break; 2394 } 2395 } 2396 } 2397 err: 2398 spin_unlock(&map->owner_lock); 2399 return ret; 2400 } 2401 2402 bool bpf_prog_map_compatible(struct bpf_map *map, const struct bpf_prog *fp) 2403 { 2404 /* XDP programs inserted into maps are not guaranteed to run on 2405 * a particular netdev (and can run outside driver context entirely 2406 * in the case of devmap and cpumap). Until device checks 2407 * are implemented, prohibit adding dev-bound programs to program maps. 2408 */ 2409 if (bpf_prog_is_dev_bound(fp->aux)) 2410 return false; 2411 2412 return __bpf_prog_map_compatible(map, fp); 2413 } 2414 2415 static int bpf_check_tail_call(const struct bpf_prog *fp) 2416 { 2417 struct bpf_prog_aux *aux = fp->aux; 2418 int i, ret = 0; 2419 2420 mutex_lock(&aux->used_maps_mutex); 2421 for (i = 0; i < aux->used_map_cnt; i++) { 2422 struct bpf_map *map = aux->used_maps[i]; 2423 2424 if (!map_type_contains_progs(map)) 2425 continue; 2426 2427 if (!__bpf_prog_map_compatible(map, fp)) { 2428 ret = -EINVAL; 2429 goto out; 2430 } 2431 } 2432 2433 out: 2434 mutex_unlock(&aux->used_maps_mutex); 2435 return ret; 2436 } 2437 2438 static bool bpf_prog_select_interpreter(struct bpf_prog *fp) 2439 { 2440 bool select_interpreter = false; 2441 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2442 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2443 u32 idx = (round_up(stack_depth, 32) / 32) - 1; 2444 2445 /* may_goto may cause stack size > 512, leading to idx out-of-bounds. 2446 * But for non-JITed programs, we don't need bpf_func, so no bounds 2447 * check needed. 2448 */ 2449 if (idx < ARRAY_SIZE(interpreters)) { 2450 fp->bpf_func = interpreters[idx]; 2451 select_interpreter = true; 2452 } else { 2453 fp->bpf_func = __bpf_prog_ret0_warn; 2454 } 2455 #else 2456 fp->bpf_func = __bpf_prog_ret0_warn; 2457 #endif 2458 return select_interpreter; 2459 } 2460 2461 /** 2462 * bpf_prog_select_runtime - select exec runtime for BPF program 2463 * @fp: bpf_prog populated with BPF program 2464 * @err: pointer to error variable 2465 * 2466 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2467 * The BPF program will be executed via bpf_prog_run() function. 2468 * 2469 * Return: the &fp argument along with &err set to 0 for success or 2470 * a negative errno code on failure 2471 */ 2472 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2473 { 2474 /* In case of BPF to BPF calls, verifier did all the prep 2475 * work with regards to JITing, etc. 2476 */ 2477 bool jit_needed = false; 2478 2479 if (fp->bpf_func) 2480 goto finalize; 2481 2482 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2483 bpf_prog_has_kfunc_call(fp)) 2484 jit_needed = true; 2485 2486 if (!bpf_prog_select_interpreter(fp)) 2487 jit_needed = true; 2488 2489 /* eBPF JITs can rewrite the program in case constant 2490 * blinding is active. However, in case of error during 2491 * blinding, bpf_int_jit_compile() must always return a 2492 * valid program, which in this case would simply not 2493 * be JITed, but falls back to the interpreter. 2494 */ 2495 if (!bpf_prog_is_offloaded(fp->aux)) { 2496 *err = bpf_prog_alloc_jited_linfo(fp); 2497 if (*err) 2498 return fp; 2499 2500 fp = bpf_int_jit_compile(fp); 2501 bpf_prog_jit_attempt_done(fp); 2502 if (!fp->jited && jit_needed) { 2503 *err = -ENOTSUPP; 2504 return fp; 2505 } 2506 } else { 2507 *err = bpf_prog_offload_compile(fp); 2508 if (*err) 2509 return fp; 2510 } 2511 2512 finalize: 2513 *err = bpf_prog_lock_ro(fp); 2514 if (*err) 2515 return fp; 2516 2517 /* The tail call compatibility check can only be done at 2518 * this late stage as we need to determine, if we deal 2519 * with JITed or non JITed program concatenations and not 2520 * all eBPF JITs might immediately support all features. 2521 */ 2522 *err = bpf_check_tail_call(fp); 2523 2524 return fp; 2525 } 2526 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2527 2528 static unsigned int __bpf_prog_ret1(const void *ctx, 2529 const struct bpf_insn *insn) 2530 { 2531 return 1; 2532 } 2533 2534 static struct bpf_prog_dummy { 2535 struct bpf_prog prog; 2536 } dummy_bpf_prog = { 2537 .prog = { 2538 .bpf_func = __bpf_prog_ret1, 2539 }, 2540 }; 2541 2542 struct bpf_empty_prog_array bpf_empty_prog_array = { 2543 .null_prog = NULL, 2544 }; 2545 EXPORT_SYMBOL(bpf_empty_prog_array); 2546 2547 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2548 { 2549 struct bpf_prog_array *p; 2550 2551 if (prog_cnt) 2552 p = kzalloc(struct_size(p, items, prog_cnt + 1), flags); 2553 else 2554 p = &bpf_empty_prog_array.hdr; 2555 2556 return p; 2557 } 2558 2559 void bpf_prog_array_free(struct bpf_prog_array *progs) 2560 { 2561 if (!progs || progs == &bpf_empty_prog_array.hdr) 2562 return; 2563 kfree_rcu(progs, rcu); 2564 } 2565 2566 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2567 { 2568 struct bpf_prog_array *progs; 2569 2570 /* If RCU Tasks Trace grace period implies RCU grace period, there is 2571 * no need to call kfree_rcu(), just call kfree() directly. 2572 */ 2573 progs = container_of(rcu, struct bpf_prog_array, rcu); 2574 if (rcu_trace_implies_rcu_gp()) 2575 kfree(progs); 2576 else 2577 kfree_rcu(progs, rcu); 2578 } 2579 2580 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2581 { 2582 if (!progs || progs == &bpf_empty_prog_array.hdr) 2583 return; 2584 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2585 } 2586 2587 int bpf_prog_array_length(struct bpf_prog_array *array) 2588 { 2589 struct bpf_prog_array_item *item; 2590 u32 cnt = 0; 2591 2592 for (item = array->items; item->prog; item++) 2593 if (item->prog != &dummy_bpf_prog.prog) 2594 cnt++; 2595 return cnt; 2596 } 2597 2598 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2599 { 2600 struct bpf_prog_array_item *item; 2601 2602 for (item = array->items; item->prog; item++) 2603 if (item->prog != &dummy_bpf_prog.prog) 2604 return false; 2605 return true; 2606 } 2607 2608 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2609 u32 *prog_ids, 2610 u32 request_cnt) 2611 { 2612 struct bpf_prog_array_item *item; 2613 int i = 0; 2614 2615 for (item = array->items; item->prog; item++) { 2616 if (item->prog == &dummy_bpf_prog.prog) 2617 continue; 2618 prog_ids[i] = item->prog->aux->id; 2619 if (++i == request_cnt) { 2620 item++; 2621 break; 2622 } 2623 } 2624 2625 return !!(item->prog); 2626 } 2627 2628 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2629 __u32 __user *prog_ids, u32 cnt) 2630 { 2631 unsigned long err = 0; 2632 bool nospc; 2633 u32 *ids; 2634 2635 /* users of this function are doing: 2636 * cnt = bpf_prog_array_length(); 2637 * if (cnt > 0) 2638 * bpf_prog_array_copy_to_user(..., cnt); 2639 * so below kcalloc doesn't need extra cnt > 0 check. 2640 */ 2641 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2642 if (!ids) 2643 return -ENOMEM; 2644 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2645 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2646 kfree(ids); 2647 if (err) 2648 return -EFAULT; 2649 if (nospc) 2650 return -ENOSPC; 2651 return 0; 2652 } 2653 2654 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2655 struct bpf_prog *old_prog) 2656 { 2657 struct bpf_prog_array_item *item; 2658 2659 for (item = array->items; item->prog; item++) 2660 if (item->prog == old_prog) { 2661 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2662 break; 2663 } 2664 } 2665 2666 /** 2667 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2668 * index into the program array with 2669 * a dummy no-op program. 2670 * @array: a bpf_prog_array 2671 * @index: the index of the program to replace 2672 * 2673 * Skips over dummy programs, by not counting them, when calculating 2674 * the position of the program to replace. 2675 * 2676 * Return: 2677 * * 0 - Success 2678 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2679 * * -ENOENT - Index out of range 2680 */ 2681 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2682 { 2683 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2684 } 2685 2686 /** 2687 * bpf_prog_array_update_at() - Updates the program at the given index 2688 * into the program array. 2689 * @array: a bpf_prog_array 2690 * @index: the index of the program to update 2691 * @prog: the program to insert into the array 2692 * 2693 * Skips over dummy programs, by not counting them, when calculating 2694 * the position of the program to update. 2695 * 2696 * Return: 2697 * * 0 - Success 2698 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2699 * * -ENOENT - Index out of range 2700 */ 2701 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2702 struct bpf_prog *prog) 2703 { 2704 struct bpf_prog_array_item *item; 2705 2706 if (unlikely(index < 0)) 2707 return -EINVAL; 2708 2709 for (item = array->items; item->prog; item++) { 2710 if (item->prog == &dummy_bpf_prog.prog) 2711 continue; 2712 if (!index) { 2713 WRITE_ONCE(item->prog, prog); 2714 return 0; 2715 } 2716 index--; 2717 } 2718 return -ENOENT; 2719 } 2720 2721 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2722 struct bpf_prog *exclude_prog, 2723 struct bpf_prog *include_prog, 2724 u64 bpf_cookie, 2725 struct bpf_prog_array **new_array) 2726 { 2727 int new_prog_cnt, carry_prog_cnt = 0; 2728 struct bpf_prog_array_item *existing, *new; 2729 struct bpf_prog_array *array; 2730 bool found_exclude = false; 2731 2732 /* Figure out how many existing progs we need to carry over to 2733 * the new array. 2734 */ 2735 if (old_array) { 2736 existing = old_array->items; 2737 for (; existing->prog; existing++) { 2738 if (existing->prog == exclude_prog) { 2739 found_exclude = true; 2740 continue; 2741 } 2742 if (existing->prog != &dummy_bpf_prog.prog) 2743 carry_prog_cnt++; 2744 if (existing->prog == include_prog) 2745 return -EEXIST; 2746 } 2747 } 2748 2749 if (exclude_prog && !found_exclude) 2750 return -ENOENT; 2751 2752 /* How many progs (not NULL) will be in the new array? */ 2753 new_prog_cnt = carry_prog_cnt; 2754 if (include_prog) 2755 new_prog_cnt += 1; 2756 2757 /* Do we have any prog (not NULL) in the new array? */ 2758 if (!new_prog_cnt) { 2759 *new_array = NULL; 2760 return 0; 2761 } 2762 2763 /* +1 as the end of prog_array is marked with NULL */ 2764 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2765 if (!array) 2766 return -ENOMEM; 2767 new = array->items; 2768 2769 /* Fill in the new prog array */ 2770 if (carry_prog_cnt) { 2771 existing = old_array->items; 2772 for (; existing->prog; existing++) { 2773 if (existing->prog == exclude_prog || 2774 existing->prog == &dummy_bpf_prog.prog) 2775 continue; 2776 2777 new->prog = existing->prog; 2778 new->bpf_cookie = existing->bpf_cookie; 2779 new++; 2780 } 2781 } 2782 if (include_prog) { 2783 new->prog = include_prog; 2784 new->bpf_cookie = bpf_cookie; 2785 new++; 2786 } 2787 new->prog = NULL; 2788 *new_array = array; 2789 return 0; 2790 } 2791 2792 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2793 u32 *prog_ids, u32 request_cnt, 2794 u32 *prog_cnt) 2795 { 2796 u32 cnt = 0; 2797 2798 if (array) 2799 cnt = bpf_prog_array_length(array); 2800 2801 *prog_cnt = cnt; 2802 2803 /* return early if user requested only program count or nothing to copy */ 2804 if (!request_cnt || !cnt) 2805 return 0; 2806 2807 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2808 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2809 : 0; 2810 } 2811 2812 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2813 struct bpf_map **used_maps, u32 len) 2814 { 2815 struct bpf_map *map; 2816 bool sleepable; 2817 u32 i; 2818 2819 sleepable = aux->prog->sleepable; 2820 for (i = 0; i < len; i++) { 2821 map = used_maps[i]; 2822 if (map->ops->map_poke_untrack) 2823 map->ops->map_poke_untrack(map, aux); 2824 if (sleepable) 2825 atomic64_dec(&map->sleepable_refcnt); 2826 bpf_map_put(map); 2827 } 2828 } 2829 2830 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2831 { 2832 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2833 kfree(aux->used_maps); 2834 } 2835 2836 void __bpf_free_used_btfs(struct btf_mod_pair *used_btfs, u32 len) 2837 { 2838 #ifdef CONFIG_BPF_SYSCALL 2839 struct btf_mod_pair *btf_mod; 2840 u32 i; 2841 2842 for (i = 0; i < len; i++) { 2843 btf_mod = &used_btfs[i]; 2844 if (btf_mod->module) 2845 module_put(btf_mod->module); 2846 btf_put(btf_mod->btf); 2847 } 2848 #endif 2849 } 2850 2851 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2852 { 2853 __bpf_free_used_btfs(aux->used_btfs, aux->used_btf_cnt); 2854 kfree(aux->used_btfs); 2855 } 2856 2857 static void bpf_prog_free_deferred(struct work_struct *work) 2858 { 2859 struct bpf_prog_aux *aux; 2860 int i; 2861 2862 aux = container_of(work, struct bpf_prog_aux, work); 2863 #ifdef CONFIG_BPF_SYSCALL 2864 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2865 bpf_prog_stream_free(aux->prog); 2866 #endif 2867 #ifdef CONFIG_CGROUP_BPF 2868 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2869 bpf_cgroup_atype_put(aux->cgroup_atype); 2870 #endif 2871 bpf_free_used_maps(aux); 2872 bpf_free_used_btfs(aux); 2873 if (bpf_prog_is_dev_bound(aux)) 2874 bpf_prog_dev_bound_destroy(aux->prog); 2875 #ifdef CONFIG_PERF_EVENTS 2876 if (aux->prog->has_callchain_buf) 2877 put_callchain_buffers(); 2878 #endif 2879 if (aux->dst_trampoline) 2880 bpf_trampoline_put(aux->dst_trampoline); 2881 for (i = 0; i < aux->real_func_cnt; i++) { 2882 /* We can just unlink the subprog poke descriptor table as 2883 * it was originally linked to the main program and is also 2884 * released along with it. 2885 */ 2886 aux->func[i]->aux->poke_tab = NULL; 2887 bpf_jit_free(aux->func[i]); 2888 } 2889 if (aux->real_func_cnt) { 2890 kfree(aux->func); 2891 bpf_prog_unlock_free(aux->prog); 2892 } else { 2893 bpf_jit_free(aux->prog); 2894 } 2895 } 2896 2897 void bpf_prog_free(struct bpf_prog *fp) 2898 { 2899 struct bpf_prog_aux *aux = fp->aux; 2900 2901 if (aux->dst_prog) 2902 bpf_prog_put(aux->dst_prog); 2903 bpf_token_put(aux->token); 2904 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2905 schedule_work(&aux->work); 2906 } 2907 EXPORT_SYMBOL_GPL(bpf_prog_free); 2908 2909 /* RNG for unprivileged user space with separated state from prandom_u32(). */ 2910 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2911 2912 void bpf_user_rnd_init_once(void) 2913 { 2914 prandom_init_once(&bpf_user_rnd_state); 2915 } 2916 2917 BPF_CALL_0(bpf_user_rnd_u32) 2918 { 2919 /* Should someone ever have the rather unwise idea to use some 2920 * of the registers passed into this function, then note that 2921 * this function is called from native eBPF and classic-to-eBPF 2922 * transformations. Register assignments from both sides are 2923 * different, f.e. classic always sets fn(ctx, A, X) here. 2924 */ 2925 struct rnd_state *state; 2926 u32 res; 2927 2928 state = &get_cpu_var(bpf_user_rnd_state); 2929 res = prandom_u32_state(state); 2930 put_cpu_var(bpf_user_rnd_state); 2931 2932 return res; 2933 } 2934 2935 BPF_CALL_0(bpf_get_raw_cpu_id) 2936 { 2937 return raw_smp_processor_id(); 2938 } 2939 2940 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2941 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2942 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2943 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2944 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2945 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2946 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2947 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2948 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2949 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2950 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2951 2952 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2953 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2954 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2955 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2956 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2957 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2958 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak; 2959 2960 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2961 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2962 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2963 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2964 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2965 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2966 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2967 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2968 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2969 const struct bpf_func_proto bpf_set_retval_proto __weak; 2970 const struct bpf_func_proto bpf_get_retval_proto __weak; 2971 2972 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2973 { 2974 return NULL; 2975 } 2976 2977 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2978 { 2979 return NULL; 2980 } 2981 2982 const struct bpf_func_proto * __weak bpf_get_perf_event_read_value_proto(void) 2983 { 2984 return NULL; 2985 } 2986 2987 u64 __weak 2988 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2989 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2990 { 2991 return -ENOTSUPP; 2992 } 2993 EXPORT_SYMBOL_GPL(bpf_event_output); 2994 2995 /* Always built-in helper functions. */ 2996 const struct bpf_func_proto bpf_tail_call_proto = { 2997 /* func is unused for tail_call, we set it to pass the 2998 * get_helper_proto check 2999 */ 3000 .func = BPF_PTR_POISON, 3001 .gpl_only = false, 3002 .ret_type = RET_VOID, 3003 .arg1_type = ARG_PTR_TO_CTX, 3004 .arg2_type = ARG_CONST_MAP_PTR, 3005 .arg3_type = ARG_ANYTHING, 3006 }; 3007 3008 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 3009 * It is encouraged to implement bpf_int_jit_compile() instead, so that 3010 * eBPF and implicitly also cBPF can get JITed! 3011 */ 3012 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 3013 { 3014 return prog; 3015 } 3016 3017 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 3018 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 3019 */ 3020 void __weak bpf_jit_compile(struct bpf_prog *prog) 3021 { 3022 } 3023 3024 bool __weak bpf_helper_changes_pkt_data(enum bpf_func_id func_id) 3025 { 3026 return false; 3027 } 3028 3029 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 3030 * analysis code and wants explicit zero extension inserted by verifier. 3031 * Otherwise, return FALSE. 3032 * 3033 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 3034 * you don't override this. JITs that don't want these extra insns can detect 3035 * them using insn_is_zext. 3036 */ 3037 bool __weak bpf_jit_needs_zext(void) 3038 { 3039 return false; 3040 } 3041 3042 /* By default, enable the verifier's mitigations against Spectre v1 and v4 for 3043 * all archs. The value returned must not change at runtime as there is 3044 * currently no support for reloading programs that were loaded without 3045 * mitigations. 3046 */ 3047 bool __weak bpf_jit_bypass_spec_v1(void) 3048 { 3049 return false; 3050 } 3051 3052 bool __weak bpf_jit_bypass_spec_v4(void) 3053 { 3054 return false; 3055 } 3056 3057 /* Return true if the JIT inlines the call to the helper corresponding to 3058 * the imm. 3059 * 3060 * The verifier will not patch the insn->imm for the call to the helper if 3061 * this returns true. 3062 */ 3063 bool __weak bpf_jit_inlines_helper_call(s32 imm) 3064 { 3065 return false; 3066 } 3067 3068 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 3069 bool __weak bpf_jit_supports_subprog_tailcalls(void) 3070 { 3071 return false; 3072 } 3073 3074 bool __weak bpf_jit_supports_percpu_insn(void) 3075 { 3076 return false; 3077 } 3078 3079 bool __weak bpf_jit_supports_kfunc_call(void) 3080 { 3081 return false; 3082 } 3083 3084 bool __weak bpf_jit_supports_far_kfunc_call(void) 3085 { 3086 return false; 3087 } 3088 3089 bool __weak bpf_jit_supports_arena(void) 3090 { 3091 return false; 3092 } 3093 3094 bool __weak bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena) 3095 { 3096 return false; 3097 } 3098 3099 u64 __weak bpf_arch_uaddress_limit(void) 3100 { 3101 #if defined(CONFIG_64BIT) && defined(CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE) 3102 return TASK_SIZE; 3103 #else 3104 return 0; 3105 #endif 3106 } 3107 3108 /* Return TRUE if the JIT backend satisfies the following two conditions: 3109 * 1) JIT backend supports atomic_xchg() on pointer-sized words. 3110 * 2) Under the specific arch, the implementation of xchg() is the same 3111 * as atomic_xchg() on pointer-sized words. 3112 */ 3113 bool __weak bpf_jit_supports_ptr_xchg(void) 3114 { 3115 return false; 3116 } 3117 3118 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 3119 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 3120 */ 3121 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 3122 int len) 3123 { 3124 return -EFAULT; 3125 } 3126 3127 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 3128 void *addr1, void *addr2) 3129 { 3130 return -ENOTSUPP; 3131 } 3132 3133 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 3134 { 3135 return ERR_PTR(-ENOTSUPP); 3136 } 3137 3138 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 3139 { 3140 return -ENOTSUPP; 3141 } 3142 3143 bool __weak bpf_jit_supports_exceptions(void) 3144 { 3145 return false; 3146 } 3147 3148 bool __weak bpf_jit_supports_private_stack(void) 3149 { 3150 return false; 3151 } 3152 3153 void __weak arch_bpf_stack_walk(bool (*consume_fn)(void *cookie, u64 ip, u64 sp, u64 bp), void *cookie) 3154 { 3155 } 3156 3157 bool __weak bpf_jit_supports_timed_may_goto(void) 3158 { 3159 return false; 3160 } 3161 3162 u64 __weak arch_bpf_timed_may_goto(void) 3163 { 3164 return 0; 3165 } 3166 3167 static noinline void bpf_prog_report_may_goto_violation(void) 3168 { 3169 #ifdef CONFIG_BPF_SYSCALL 3170 struct bpf_stream_stage ss; 3171 struct bpf_prog *prog; 3172 3173 prog = bpf_prog_find_from_stack(); 3174 if (!prog) 3175 return; 3176 bpf_stream_stage(ss, prog, BPF_STDERR, ({ 3177 bpf_stream_printk(ss, "ERROR: Timeout detected for may_goto instruction\n"); 3178 bpf_stream_dump_stack(ss); 3179 })); 3180 #endif 3181 } 3182 3183 u64 bpf_check_timed_may_goto(struct bpf_timed_may_goto *p) 3184 { 3185 u64 time = ktime_get_mono_fast_ns(); 3186 3187 /* Populate the timestamp for this stack frame, and refresh count. */ 3188 if (!p->timestamp) { 3189 p->timestamp = time; 3190 return BPF_MAX_TIMED_LOOPS; 3191 } 3192 /* Check if we've exhausted our time slice, and zero count. */ 3193 if (unlikely(time - p->timestamp >= (NSEC_PER_SEC / 4))) { 3194 bpf_prog_report_may_goto_violation(); 3195 return 0; 3196 } 3197 /* Refresh the count for the stack frame. */ 3198 return BPF_MAX_TIMED_LOOPS; 3199 } 3200 3201 /* for configs without MMU or 32-bit */ 3202 __weak const struct bpf_map_ops arena_map_ops; 3203 __weak u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena) 3204 { 3205 return 0; 3206 } 3207 __weak u64 bpf_arena_get_kern_vm_start(struct bpf_arena *arena) 3208 { 3209 return 0; 3210 } 3211 3212 #ifdef CONFIG_BPF_SYSCALL 3213 static int __init bpf_global_ma_init(void) 3214 { 3215 int ret; 3216 3217 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); 3218 bpf_global_ma_set = !ret; 3219 return ret; 3220 } 3221 late_initcall(bpf_global_ma_init); 3222 #endif 3223 3224 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 3225 EXPORT_SYMBOL(bpf_stats_enabled_key); 3226 3227 /* All definitions of tracepoints related to BPF. */ 3228 #define CREATE_TRACE_POINTS 3229 #include <linux/bpf_trace.h> 3230 3231 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 3232 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 3233 3234 #ifdef CONFIG_BPF_SYSCALL 3235 3236 int bpf_prog_get_file_line(struct bpf_prog *prog, unsigned long ip, const char **filep, 3237 const char **linep, int *nump) 3238 { 3239 int idx = -1, insn_start, insn_end, len; 3240 struct bpf_line_info *linfo; 3241 void **jited_linfo; 3242 struct btf *btf; 3243 int nr_linfo; 3244 3245 btf = prog->aux->btf; 3246 linfo = prog->aux->linfo; 3247 jited_linfo = prog->aux->jited_linfo; 3248 3249 if (!btf || !linfo || !jited_linfo) 3250 return -EINVAL; 3251 len = prog->aux->func ? prog->aux->func[prog->aux->func_idx]->len : prog->len; 3252 3253 linfo = &prog->aux->linfo[prog->aux->linfo_idx]; 3254 jited_linfo = &prog->aux->jited_linfo[prog->aux->linfo_idx]; 3255 3256 insn_start = linfo[0].insn_off; 3257 insn_end = insn_start + len; 3258 nr_linfo = prog->aux->nr_linfo - prog->aux->linfo_idx; 3259 3260 for (int i = 0; i < nr_linfo && 3261 linfo[i].insn_off >= insn_start && linfo[i].insn_off < insn_end; i++) { 3262 if (jited_linfo[i] >= (void *)ip) 3263 break; 3264 idx = i; 3265 } 3266 3267 if (idx == -1) 3268 return -ENOENT; 3269 3270 /* Get base component of the file path. */ 3271 *filep = btf_name_by_offset(btf, linfo[idx].file_name_off); 3272 *filep = kbasename(*filep); 3273 /* Obtain the source line, and strip whitespace in prefix. */ 3274 *linep = btf_name_by_offset(btf, linfo[idx].line_off); 3275 while (isspace(**linep)) 3276 *linep += 1; 3277 *nump = BPF_LINE_INFO_LINE_NUM(linfo[idx].line_col); 3278 return 0; 3279 } 3280 3281 struct walk_stack_ctx { 3282 struct bpf_prog *prog; 3283 }; 3284 3285 static bool find_from_stack_cb(void *cookie, u64 ip, u64 sp, u64 bp) 3286 { 3287 struct walk_stack_ctx *ctxp = cookie; 3288 struct bpf_prog *prog; 3289 3290 /* 3291 * The RCU read lock is held to safely traverse the latch tree, but we 3292 * don't need its protection when accessing the prog, since it has an 3293 * active stack frame on the current stack trace, and won't disappear. 3294 */ 3295 rcu_read_lock(); 3296 prog = bpf_prog_ksym_find(ip); 3297 rcu_read_unlock(); 3298 if (!prog) 3299 return true; 3300 /* Make sure we return the main prog if we found a subprog */ 3301 ctxp->prog = prog->aux->main_prog_aux->prog; 3302 return false; 3303 } 3304 3305 struct bpf_prog *bpf_prog_find_from_stack(void) 3306 { 3307 struct walk_stack_ctx ctx = {}; 3308 3309 arch_bpf_stack_walk(find_from_stack_cb, &ctx); 3310 return ctx.prog; 3311 } 3312 3313 #endif 3314