1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com 2 * 3 * This program is free software; you can redistribute it and/or 4 * modify it under the terms of version 2 of the GNU General Public 5 * License as published by the Free Software Foundation. 6 * 7 * This program is distributed in the hope that it will be useful, but 8 * WITHOUT ANY WARRANTY; without even the implied warranty of 9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 10 * General Public License for more details. 11 */ 12 #include <linux/bpf.h> 13 #include <linux/syscalls.h> 14 #include <linux/slab.h> 15 #include <linux/anon_inodes.h> 16 #include <linux/file.h> 17 #include <linux/license.h> 18 #include <linux/filter.h> 19 #include <linux/version.h> 20 #include <linux/kernel.h> 21 22 DEFINE_PER_CPU(int, bpf_prog_active); 23 24 int sysctl_unprivileged_bpf_disabled __read_mostly; 25 26 static LIST_HEAD(bpf_map_types); 27 28 static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) 29 { 30 struct bpf_map_type_list *tl; 31 struct bpf_map *map; 32 33 list_for_each_entry(tl, &bpf_map_types, list_node) { 34 if (tl->type == attr->map_type) { 35 map = tl->ops->map_alloc(attr); 36 if (IS_ERR(map)) 37 return map; 38 map->ops = tl->ops; 39 map->map_type = attr->map_type; 40 return map; 41 } 42 } 43 return ERR_PTR(-EINVAL); 44 } 45 46 /* boot time registration of different map implementations */ 47 void bpf_register_map_type(struct bpf_map_type_list *tl) 48 { 49 list_add(&tl->list_node, &bpf_map_types); 50 } 51 52 int bpf_map_precharge_memlock(u32 pages) 53 { 54 struct user_struct *user = get_current_user(); 55 unsigned long memlock_limit, cur; 56 57 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 58 cur = atomic_long_read(&user->locked_vm); 59 free_uid(user); 60 if (cur + pages > memlock_limit) 61 return -EPERM; 62 return 0; 63 } 64 65 static int bpf_map_charge_memlock(struct bpf_map *map) 66 { 67 struct user_struct *user = get_current_user(); 68 unsigned long memlock_limit; 69 70 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 71 72 atomic_long_add(map->pages, &user->locked_vm); 73 74 if (atomic_long_read(&user->locked_vm) > memlock_limit) { 75 atomic_long_sub(map->pages, &user->locked_vm); 76 free_uid(user); 77 return -EPERM; 78 } 79 map->user = user; 80 return 0; 81 } 82 83 static void bpf_map_uncharge_memlock(struct bpf_map *map) 84 { 85 struct user_struct *user = map->user; 86 87 atomic_long_sub(map->pages, &user->locked_vm); 88 free_uid(user); 89 } 90 91 /* called from workqueue */ 92 static void bpf_map_free_deferred(struct work_struct *work) 93 { 94 struct bpf_map *map = container_of(work, struct bpf_map, work); 95 96 bpf_map_uncharge_memlock(map); 97 /* implementation dependent freeing */ 98 map->ops->map_free(map); 99 } 100 101 static void bpf_map_put_uref(struct bpf_map *map) 102 { 103 if (atomic_dec_and_test(&map->usercnt)) { 104 if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY) 105 bpf_fd_array_map_clear(map); 106 } 107 } 108 109 /* decrement map refcnt and schedule it for freeing via workqueue 110 * (unrelying map implementation ops->map_free() might sleep) 111 */ 112 void bpf_map_put(struct bpf_map *map) 113 { 114 if (atomic_dec_and_test(&map->refcnt)) { 115 INIT_WORK(&map->work, bpf_map_free_deferred); 116 schedule_work(&map->work); 117 } 118 } 119 120 void bpf_map_put_with_uref(struct bpf_map *map) 121 { 122 bpf_map_put_uref(map); 123 bpf_map_put(map); 124 } 125 126 static int bpf_map_release(struct inode *inode, struct file *filp) 127 { 128 struct bpf_map *map = filp->private_data; 129 130 if (map->ops->map_release) 131 map->ops->map_release(map, filp); 132 133 bpf_map_put_with_uref(map); 134 return 0; 135 } 136 137 #ifdef CONFIG_PROC_FS 138 static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp) 139 { 140 const struct bpf_map *map = filp->private_data; 141 const struct bpf_array *array; 142 u32 owner_prog_type = 0; 143 144 if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY) { 145 array = container_of(map, struct bpf_array, map); 146 owner_prog_type = array->owner_prog_type; 147 } 148 149 seq_printf(m, 150 "map_type:\t%u\n" 151 "key_size:\t%u\n" 152 "value_size:\t%u\n" 153 "max_entries:\t%u\n" 154 "map_flags:\t%#x\n" 155 "memlock:\t%llu\n", 156 map->map_type, 157 map->key_size, 158 map->value_size, 159 map->max_entries, 160 map->map_flags, 161 map->pages * 1ULL << PAGE_SHIFT); 162 163 if (owner_prog_type) 164 seq_printf(m, "owner_prog_type:\t%u\n", 165 owner_prog_type); 166 } 167 #endif 168 169 static const struct file_operations bpf_map_fops = { 170 #ifdef CONFIG_PROC_FS 171 .show_fdinfo = bpf_map_show_fdinfo, 172 #endif 173 .release = bpf_map_release, 174 }; 175 176 int bpf_map_new_fd(struct bpf_map *map) 177 { 178 return anon_inode_getfd("bpf-map", &bpf_map_fops, map, 179 O_RDWR | O_CLOEXEC); 180 } 181 182 /* helper macro to check that unused fields 'union bpf_attr' are zero */ 183 #define CHECK_ATTR(CMD) \ 184 memchr_inv((void *) &attr->CMD##_LAST_FIELD + \ 185 sizeof(attr->CMD##_LAST_FIELD), 0, \ 186 sizeof(*attr) - \ 187 offsetof(union bpf_attr, CMD##_LAST_FIELD) - \ 188 sizeof(attr->CMD##_LAST_FIELD)) != NULL 189 190 #define BPF_MAP_CREATE_LAST_FIELD map_flags 191 /* called via syscall */ 192 static int map_create(union bpf_attr *attr) 193 { 194 struct bpf_map *map; 195 int err; 196 197 err = CHECK_ATTR(BPF_MAP_CREATE); 198 if (err) 199 return -EINVAL; 200 201 /* find map type and init map: hashtable vs rbtree vs bloom vs ... */ 202 map = find_and_alloc_map(attr); 203 if (IS_ERR(map)) 204 return PTR_ERR(map); 205 206 atomic_set(&map->refcnt, 1); 207 atomic_set(&map->usercnt, 1); 208 209 err = bpf_map_charge_memlock(map); 210 if (err) 211 goto free_map_nouncharge; 212 213 err = bpf_map_new_fd(map); 214 if (err < 0) 215 /* failed to allocate fd */ 216 goto free_map; 217 218 return err; 219 220 free_map: 221 bpf_map_uncharge_memlock(map); 222 free_map_nouncharge: 223 map->ops->map_free(map); 224 return err; 225 } 226 227 /* if error is returned, fd is released. 228 * On success caller should complete fd access with matching fdput() 229 */ 230 struct bpf_map *__bpf_map_get(struct fd f) 231 { 232 if (!f.file) 233 return ERR_PTR(-EBADF); 234 if (f.file->f_op != &bpf_map_fops) { 235 fdput(f); 236 return ERR_PTR(-EINVAL); 237 } 238 239 return f.file->private_data; 240 } 241 242 /* prog's and map's refcnt limit */ 243 #define BPF_MAX_REFCNT 32768 244 245 struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref) 246 { 247 if (atomic_inc_return(&map->refcnt) > BPF_MAX_REFCNT) { 248 atomic_dec(&map->refcnt); 249 return ERR_PTR(-EBUSY); 250 } 251 if (uref) 252 atomic_inc(&map->usercnt); 253 return map; 254 } 255 256 struct bpf_map *bpf_map_get_with_uref(u32 ufd) 257 { 258 struct fd f = fdget(ufd); 259 struct bpf_map *map; 260 261 map = __bpf_map_get(f); 262 if (IS_ERR(map)) 263 return map; 264 265 map = bpf_map_inc(map, true); 266 fdput(f); 267 268 return map; 269 } 270 271 int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value) 272 { 273 return -ENOTSUPP; 274 } 275 276 /* last field in 'union bpf_attr' used by this command */ 277 #define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value 278 279 static int map_lookup_elem(union bpf_attr *attr) 280 { 281 void __user *ukey = u64_to_user_ptr(attr->key); 282 void __user *uvalue = u64_to_user_ptr(attr->value); 283 int ufd = attr->map_fd; 284 struct bpf_map *map; 285 void *key, *value, *ptr; 286 u32 value_size; 287 struct fd f; 288 int err; 289 290 if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM)) 291 return -EINVAL; 292 293 f = fdget(ufd); 294 map = __bpf_map_get(f); 295 if (IS_ERR(map)) 296 return PTR_ERR(map); 297 298 err = -ENOMEM; 299 key = kmalloc(map->key_size, GFP_USER); 300 if (!key) 301 goto err_put; 302 303 err = -EFAULT; 304 if (copy_from_user(key, ukey, map->key_size) != 0) 305 goto free_key; 306 307 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 308 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || 309 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) 310 value_size = round_up(map->value_size, 8) * num_possible_cpus(); 311 else 312 value_size = map->value_size; 313 314 err = -ENOMEM; 315 value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); 316 if (!value) 317 goto free_key; 318 319 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 320 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { 321 err = bpf_percpu_hash_copy(map, key, value); 322 } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { 323 err = bpf_percpu_array_copy(map, key, value); 324 } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) { 325 err = bpf_stackmap_copy(map, key, value); 326 } else { 327 rcu_read_lock(); 328 ptr = map->ops->map_lookup_elem(map, key); 329 if (ptr) 330 memcpy(value, ptr, value_size); 331 rcu_read_unlock(); 332 err = ptr ? 0 : -ENOENT; 333 } 334 335 if (err) 336 goto free_value; 337 338 err = -EFAULT; 339 if (copy_to_user(uvalue, value, value_size) != 0) 340 goto free_value; 341 342 err = 0; 343 344 free_value: 345 kfree(value); 346 free_key: 347 kfree(key); 348 err_put: 349 fdput(f); 350 return err; 351 } 352 353 #define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags 354 355 static int map_update_elem(union bpf_attr *attr) 356 { 357 void __user *ukey = u64_to_user_ptr(attr->key); 358 void __user *uvalue = u64_to_user_ptr(attr->value); 359 int ufd = attr->map_fd; 360 struct bpf_map *map; 361 void *key, *value; 362 u32 value_size; 363 struct fd f; 364 int err; 365 366 if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM)) 367 return -EINVAL; 368 369 f = fdget(ufd); 370 map = __bpf_map_get(f); 371 if (IS_ERR(map)) 372 return PTR_ERR(map); 373 374 err = -ENOMEM; 375 key = kmalloc(map->key_size, GFP_USER); 376 if (!key) 377 goto err_put; 378 379 err = -EFAULT; 380 if (copy_from_user(key, ukey, map->key_size) != 0) 381 goto free_key; 382 383 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 384 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || 385 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) 386 value_size = round_up(map->value_size, 8) * num_possible_cpus(); 387 else 388 value_size = map->value_size; 389 390 err = -ENOMEM; 391 value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); 392 if (!value) 393 goto free_key; 394 395 err = -EFAULT; 396 if (copy_from_user(value, uvalue, value_size) != 0) 397 goto free_value; 398 399 /* must increment bpf_prog_active to avoid kprobe+bpf triggering from 400 * inside bpf map update or delete otherwise deadlocks are possible 401 */ 402 preempt_disable(); 403 __this_cpu_inc(bpf_prog_active); 404 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 405 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { 406 err = bpf_percpu_hash_update(map, key, value, attr->flags); 407 } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { 408 err = bpf_percpu_array_update(map, key, value, attr->flags); 409 } else if (map->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || 410 map->map_type == BPF_MAP_TYPE_PROG_ARRAY || 411 map->map_type == BPF_MAP_TYPE_CGROUP_ARRAY) { 412 rcu_read_lock(); 413 err = bpf_fd_array_map_update_elem(map, f.file, key, value, 414 attr->flags); 415 rcu_read_unlock(); 416 } else { 417 rcu_read_lock(); 418 err = map->ops->map_update_elem(map, key, value, attr->flags); 419 rcu_read_unlock(); 420 } 421 __this_cpu_dec(bpf_prog_active); 422 preempt_enable(); 423 424 free_value: 425 kfree(value); 426 free_key: 427 kfree(key); 428 err_put: 429 fdput(f); 430 return err; 431 } 432 433 #define BPF_MAP_DELETE_ELEM_LAST_FIELD key 434 435 static int map_delete_elem(union bpf_attr *attr) 436 { 437 void __user *ukey = u64_to_user_ptr(attr->key); 438 int ufd = attr->map_fd; 439 struct bpf_map *map; 440 struct fd f; 441 void *key; 442 int err; 443 444 if (CHECK_ATTR(BPF_MAP_DELETE_ELEM)) 445 return -EINVAL; 446 447 f = fdget(ufd); 448 map = __bpf_map_get(f); 449 if (IS_ERR(map)) 450 return PTR_ERR(map); 451 452 err = -ENOMEM; 453 key = kmalloc(map->key_size, GFP_USER); 454 if (!key) 455 goto err_put; 456 457 err = -EFAULT; 458 if (copy_from_user(key, ukey, map->key_size) != 0) 459 goto free_key; 460 461 preempt_disable(); 462 __this_cpu_inc(bpf_prog_active); 463 rcu_read_lock(); 464 err = map->ops->map_delete_elem(map, key); 465 rcu_read_unlock(); 466 __this_cpu_dec(bpf_prog_active); 467 preempt_enable(); 468 469 free_key: 470 kfree(key); 471 err_put: 472 fdput(f); 473 return err; 474 } 475 476 /* last field in 'union bpf_attr' used by this command */ 477 #define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key 478 479 static int map_get_next_key(union bpf_attr *attr) 480 { 481 void __user *ukey = u64_to_user_ptr(attr->key); 482 void __user *unext_key = u64_to_user_ptr(attr->next_key); 483 int ufd = attr->map_fd; 484 struct bpf_map *map; 485 void *key, *next_key; 486 struct fd f; 487 int err; 488 489 if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY)) 490 return -EINVAL; 491 492 f = fdget(ufd); 493 map = __bpf_map_get(f); 494 if (IS_ERR(map)) 495 return PTR_ERR(map); 496 497 err = -ENOMEM; 498 key = kmalloc(map->key_size, GFP_USER); 499 if (!key) 500 goto err_put; 501 502 err = -EFAULT; 503 if (copy_from_user(key, ukey, map->key_size) != 0) 504 goto free_key; 505 506 err = -ENOMEM; 507 next_key = kmalloc(map->key_size, GFP_USER); 508 if (!next_key) 509 goto free_key; 510 511 rcu_read_lock(); 512 err = map->ops->map_get_next_key(map, key, next_key); 513 rcu_read_unlock(); 514 if (err) 515 goto free_next_key; 516 517 err = -EFAULT; 518 if (copy_to_user(unext_key, next_key, map->key_size) != 0) 519 goto free_next_key; 520 521 err = 0; 522 523 free_next_key: 524 kfree(next_key); 525 free_key: 526 kfree(key); 527 err_put: 528 fdput(f); 529 return err; 530 } 531 532 static LIST_HEAD(bpf_prog_types); 533 534 static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog) 535 { 536 struct bpf_prog_type_list *tl; 537 538 list_for_each_entry(tl, &bpf_prog_types, list_node) { 539 if (tl->type == type) { 540 prog->aux->ops = tl->ops; 541 prog->type = type; 542 return 0; 543 } 544 } 545 546 return -EINVAL; 547 } 548 549 void bpf_register_prog_type(struct bpf_prog_type_list *tl) 550 { 551 list_add(&tl->list_node, &bpf_prog_types); 552 } 553 554 /* fixup insn->imm field of bpf_call instructions: 555 * if (insn->imm == BPF_FUNC_map_lookup_elem) 556 * insn->imm = bpf_map_lookup_elem - __bpf_call_base; 557 * else if (insn->imm == BPF_FUNC_map_update_elem) 558 * insn->imm = bpf_map_update_elem - __bpf_call_base; 559 * else ... 560 * 561 * this function is called after eBPF program passed verification 562 */ 563 static void fixup_bpf_calls(struct bpf_prog *prog) 564 { 565 const struct bpf_func_proto *fn; 566 int i; 567 568 for (i = 0; i < prog->len; i++) { 569 struct bpf_insn *insn = &prog->insnsi[i]; 570 571 if (insn->code == (BPF_JMP | BPF_CALL)) { 572 /* we reach here when program has bpf_call instructions 573 * and it passed bpf_check(), means that 574 * ops->get_func_proto must have been supplied, check it 575 */ 576 BUG_ON(!prog->aux->ops->get_func_proto); 577 578 if (insn->imm == BPF_FUNC_get_route_realm) 579 prog->dst_needed = 1; 580 if (insn->imm == BPF_FUNC_get_prandom_u32) 581 bpf_user_rnd_init_once(); 582 if (insn->imm == BPF_FUNC_xdp_adjust_head) 583 prog->xdp_adjust_head = 1; 584 if (insn->imm == BPF_FUNC_tail_call) { 585 /* mark bpf_tail_call as different opcode 586 * to avoid conditional branch in 587 * interpeter for every normal call 588 * and to prevent accidental JITing by 589 * JIT compiler that doesn't support 590 * bpf_tail_call yet 591 */ 592 insn->imm = 0; 593 insn->code |= BPF_X; 594 continue; 595 } 596 597 fn = prog->aux->ops->get_func_proto(insn->imm); 598 /* all functions that have prototype and verifier allowed 599 * programs to call them, must be real in-kernel functions 600 */ 601 BUG_ON(!fn->func); 602 insn->imm = fn->func - __bpf_call_base; 603 } 604 } 605 } 606 607 /* drop refcnt on maps used by eBPF program and free auxilary data */ 608 static void free_used_maps(struct bpf_prog_aux *aux) 609 { 610 int i; 611 612 for (i = 0; i < aux->used_map_cnt; i++) 613 bpf_map_put(aux->used_maps[i]); 614 615 kfree(aux->used_maps); 616 } 617 618 int __bpf_prog_charge(struct user_struct *user, u32 pages) 619 { 620 unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 621 unsigned long user_bufs; 622 623 if (user) { 624 user_bufs = atomic_long_add_return(pages, &user->locked_vm); 625 if (user_bufs > memlock_limit) { 626 atomic_long_sub(pages, &user->locked_vm); 627 return -EPERM; 628 } 629 } 630 631 return 0; 632 } 633 634 void __bpf_prog_uncharge(struct user_struct *user, u32 pages) 635 { 636 if (user) 637 atomic_long_sub(pages, &user->locked_vm); 638 } 639 640 static int bpf_prog_charge_memlock(struct bpf_prog *prog) 641 { 642 struct user_struct *user = get_current_user(); 643 int ret; 644 645 ret = __bpf_prog_charge(user, prog->pages); 646 if (ret) { 647 free_uid(user); 648 return ret; 649 } 650 651 prog->aux->user = user; 652 return 0; 653 } 654 655 static void bpf_prog_uncharge_memlock(struct bpf_prog *prog) 656 { 657 struct user_struct *user = prog->aux->user; 658 659 __bpf_prog_uncharge(user, prog->pages); 660 free_uid(user); 661 } 662 663 static void __bpf_prog_put_rcu(struct rcu_head *rcu) 664 { 665 struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu); 666 667 free_used_maps(aux); 668 bpf_prog_uncharge_memlock(aux->prog); 669 bpf_prog_free(aux->prog); 670 } 671 672 void bpf_prog_put(struct bpf_prog *prog) 673 { 674 if (atomic_dec_and_test(&prog->aux->refcnt)) 675 call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu); 676 } 677 EXPORT_SYMBOL_GPL(bpf_prog_put); 678 679 static int bpf_prog_release(struct inode *inode, struct file *filp) 680 { 681 struct bpf_prog *prog = filp->private_data; 682 683 bpf_prog_put(prog); 684 return 0; 685 } 686 687 #ifdef CONFIG_PROC_FS 688 static void bpf_prog_show_fdinfo(struct seq_file *m, struct file *filp) 689 { 690 const struct bpf_prog *prog = filp->private_data; 691 char prog_digest[sizeof(prog->digest) * 2 + 1] = { }; 692 693 bin2hex(prog_digest, prog->digest, sizeof(prog->digest)); 694 seq_printf(m, 695 "prog_type:\t%u\n" 696 "prog_jited:\t%u\n" 697 "prog_digest:\t%s\n" 698 "memlock:\t%llu\n", 699 prog->type, 700 prog->jited, 701 prog_digest, 702 prog->pages * 1ULL << PAGE_SHIFT); 703 } 704 #endif 705 706 static const struct file_operations bpf_prog_fops = { 707 #ifdef CONFIG_PROC_FS 708 .show_fdinfo = bpf_prog_show_fdinfo, 709 #endif 710 .release = bpf_prog_release, 711 }; 712 713 int bpf_prog_new_fd(struct bpf_prog *prog) 714 { 715 return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog, 716 O_RDWR | O_CLOEXEC); 717 } 718 719 static struct bpf_prog *____bpf_prog_get(struct fd f) 720 { 721 if (!f.file) 722 return ERR_PTR(-EBADF); 723 if (f.file->f_op != &bpf_prog_fops) { 724 fdput(f); 725 return ERR_PTR(-EINVAL); 726 } 727 728 return f.file->private_data; 729 } 730 731 struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i) 732 { 733 if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) { 734 atomic_sub(i, &prog->aux->refcnt); 735 return ERR_PTR(-EBUSY); 736 } 737 return prog; 738 } 739 EXPORT_SYMBOL_GPL(bpf_prog_add); 740 741 void bpf_prog_sub(struct bpf_prog *prog, int i) 742 { 743 /* Only to be used for undoing previous bpf_prog_add() in some 744 * error path. We still know that another entity in our call 745 * path holds a reference to the program, thus atomic_sub() can 746 * be safely used in such cases! 747 */ 748 WARN_ON(atomic_sub_return(i, &prog->aux->refcnt) == 0); 749 } 750 EXPORT_SYMBOL_GPL(bpf_prog_sub); 751 752 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) 753 { 754 return bpf_prog_add(prog, 1); 755 } 756 EXPORT_SYMBOL_GPL(bpf_prog_inc); 757 758 static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type) 759 { 760 struct fd f = fdget(ufd); 761 struct bpf_prog *prog; 762 763 prog = ____bpf_prog_get(f); 764 if (IS_ERR(prog)) 765 return prog; 766 if (type && prog->type != *type) { 767 prog = ERR_PTR(-EINVAL); 768 goto out; 769 } 770 771 prog = bpf_prog_inc(prog); 772 out: 773 fdput(f); 774 return prog; 775 } 776 777 struct bpf_prog *bpf_prog_get(u32 ufd) 778 { 779 return __bpf_prog_get(ufd, NULL); 780 } 781 782 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type) 783 { 784 return __bpf_prog_get(ufd, &type); 785 } 786 EXPORT_SYMBOL_GPL(bpf_prog_get_type); 787 788 /* last field in 'union bpf_attr' used by this command */ 789 #define BPF_PROG_LOAD_LAST_FIELD kern_version 790 791 static int bpf_prog_load(union bpf_attr *attr) 792 { 793 enum bpf_prog_type type = attr->prog_type; 794 struct bpf_prog *prog; 795 int err; 796 char license[128]; 797 bool is_gpl; 798 799 if (CHECK_ATTR(BPF_PROG_LOAD)) 800 return -EINVAL; 801 802 /* copy eBPF program license from user space */ 803 if (strncpy_from_user(license, u64_to_user_ptr(attr->license), 804 sizeof(license) - 1) < 0) 805 return -EFAULT; 806 license[sizeof(license) - 1] = 0; 807 808 /* eBPF programs must be GPL compatible to use GPL-ed functions */ 809 is_gpl = license_is_gpl_compatible(license); 810 811 if (attr->insn_cnt == 0 || attr->insn_cnt > BPF_MAXINSNS) 812 return -E2BIG; 813 814 if (type == BPF_PROG_TYPE_KPROBE && 815 attr->kern_version != LINUX_VERSION_CODE) 816 return -EINVAL; 817 818 if (type != BPF_PROG_TYPE_SOCKET_FILTER && !capable(CAP_SYS_ADMIN)) 819 return -EPERM; 820 821 /* plain bpf_prog allocation */ 822 prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER); 823 if (!prog) 824 return -ENOMEM; 825 826 err = bpf_prog_charge_memlock(prog); 827 if (err) 828 goto free_prog_nouncharge; 829 830 prog->len = attr->insn_cnt; 831 832 err = -EFAULT; 833 if (copy_from_user(prog->insns, u64_to_user_ptr(attr->insns), 834 bpf_prog_insn_size(prog)) != 0) 835 goto free_prog; 836 837 prog->orig_prog = NULL; 838 prog->jited = 0; 839 840 atomic_set(&prog->aux->refcnt, 1); 841 prog->gpl_compatible = is_gpl ? 1 : 0; 842 843 /* find program type: socket_filter vs tracing_filter */ 844 err = find_prog_type(type, prog); 845 if (err < 0) 846 goto free_prog; 847 848 /* run eBPF verifier */ 849 err = bpf_check(&prog, attr); 850 if (err < 0) 851 goto free_used_maps; 852 853 /* fixup BPF_CALL->imm field */ 854 fixup_bpf_calls(prog); 855 856 /* eBPF program is ready to be JITed */ 857 prog = bpf_prog_select_runtime(prog, &err); 858 if (err < 0) 859 goto free_used_maps; 860 861 err = bpf_prog_new_fd(prog); 862 if (err < 0) 863 /* failed to allocate fd */ 864 goto free_used_maps; 865 866 return err; 867 868 free_used_maps: 869 free_used_maps(prog->aux); 870 free_prog: 871 bpf_prog_uncharge_memlock(prog); 872 free_prog_nouncharge: 873 bpf_prog_free(prog); 874 return err; 875 } 876 877 #define BPF_OBJ_LAST_FIELD bpf_fd 878 879 static int bpf_obj_pin(const union bpf_attr *attr) 880 { 881 if (CHECK_ATTR(BPF_OBJ)) 882 return -EINVAL; 883 884 return bpf_obj_pin_user(attr->bpf_fd, u64_to_user_ptr(attr->pathname)); 885 } 886 887 static int bpf_obj_get(const union bpf_attr *attr) 888 { 889 if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0) 890 return -EINVAL; 891 892 return bpf_obj_get_user(u64_to_user_ptr(attr->pathname)); 893 } 894 895 #ifdef CONFIG_CGROUP_BPF 896 897 #define BPF_PROG_ATTACH_LAST_FIELD attach_type 898 899 static int bpf_prog_attach(const union bpf_attr *attr) 900 { 901 struct bpf_prog *prog; 902 struct cgroup *cgrp; 903 enum bpf_prog_type ptype; 904 905 if (!capable(CAP_NET_ADMIN)) 906 return -EPERM; 907 908 if (CHECK_ATTR(BPF_PROG_ATTACH)) 909 return -EINVAL; 910 911 switch (attr->attach_type) { 912 case BPF_CGROUP_INET_INGRESS: 913 case BPF_CGROUP_INET_EGRESS: 914 ptype = BPF_PROG_TYPE_CGROUP_SKB; 915 break; 916 case BPF_CGROUP_INET_SOCK_CREATE: 917 ptype = BPF_PROG_TYPE_CGROUP_SOCK; 918 break; 919 default: 920 return -EINVAL; 921 } 922 923 prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype); 924 if (IS_ERR(prog)) 925 return PTR_ERR(prog); 926 927 cgrp = cgroup_get_from_fd(attr->target_fd); 928 if (IS_ERR(cgrp)) { 929 bpf_prog_put(prog); 930 return PTR_ERR(cgrp); 931 } 932 933 cgroup_bpf_update(cgrp, prog, attr->attach_type); 934 cgroup_put(cgrp); 935 936 return 0; 937 } 938 939 #define BPF_PROG_DETACH_LAST_FIELD attach_type 940 941 static int bpf_prog_detach(const union bpf_attr *attr) 942 { 943 struct cgroup *cgrp; 944 945 if (!capable(CAP_NET_ADMIN)) 946 return -EPERM; 947 948 if (CHECK_ATTR(BPF_PROG_DETACH)) 949 return -EINVAL; 950 951 switch (attr->attach_type) { 952 case BPF_CGROUP_INET_INGRESS: 953 case BPF_CGROUP_INET_EGRESS: 954 case BPF_CGROUP_INET_SOCK_CREATE: 955 cgrp = cgroup_get_from_fd(attr->target_fd); 956 if (IS_ERR(cgrp)) 957 return PTR_ERR(cgrp); 958 959 cgroup_bpf_update(cgrp, NULL, attr->attach_type); 960 cgroup_put(cgrp); 961 break; 962 963 default: 964 return -EINVAL; 965 } 966 967 return 0; 968 } 969 #endif /* CONFIG_CGROUP_BPF */ 970 971 SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) 972 { 973 union bpf_attr attr = {}; 974 int err; 975 976 if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled) 977 return -EPERM; 978 979 if (!access_ok(VERIFY_READ, uattr, 1)) 980 return -EFAULT; 981 982 if (size > PAGE_SIZE) /* silly large */ 983 return -E2BIG; 984 985 /* If we're handed a bigger struct than we know of, 986 * ensure all the unknown bits are 0 - i.e. new 987 * user-space does not rely on any kernel feature 988 * extensions we dont know about yet. 989 */ 990 if (size > sizeof(attr)) { 991 unsigned char __user *addr; 992 unsigned char __user *end; 993 unsigned char val; 994 995 addr = (void __user *)uattr + sizeof(attr); 996 end = (void __user *)uattr + size; 997 998 for (; addr < end; addr++) { 999 err = get_user(val, addr); 1000 if (err) 1001 return err; 1002 if (val) 1003 return -E2BIG; 1004 } 1005 size = sizeof(attr); 1006 } 1007 1008 /* copy attributes from user space, may be less than sizeof(bpf_attr) */ 1009 if (copy_from_user(&attr, uattr, size) != 0) 1010 return -EFAULT; 1011 1012 switch (cmd) { 1013 case BPF_MAP_CREATE: 1014 err = map_create(&attr); 1015 break; 1016 case BPF_MAP_LOOKUP_ELEM: 1017 err = map_lookup_elem(&attr); 1018 break; 1019 case BPF_MAP_UPDATE_ELEM: 1020 err = map_update_elem(&attr); 1021 break; 1022 case BPF_MAP_DELETE_ELEM: 1023 err = map_delete_elem(&attr); 1024 break; 1025 case BPF_MAP_GET_NEXT_KEY: 1026 err = map_get_next_key(&attr); 1027 break; 1028 case BPF_PROG_LOAD: 1029 err = bpf_prog_load(&attr); 1030 break; 1031 case BPF_OBJ_PIN: 1032 err = bpf_obj_pin(&attr); 1033 break; 1034 case BPF_OBJ_GET: 1035 err = bpf_obj_get(&attr); 1036 break; 1037 1038 #ifdef CONFIG_CGROUP_BPF 1039 case BPF_PROG_ATTACH: 1040 err = bpf_prog_attach(&attr); 1041 break; 1042 case BPF_PROG_DETACH: 1043 err = bpf_prog_detach(&attr); 1044 break; 1045 #endif 1046 1047 default: 1048 err = -EINVAL; 1049 break; 1050 } 1051 1052 return err; 1053 } 1054