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 21 DEFINE_PER_CPU(int, bpf_prog_active); 22 23 int sysctl_unprivileged_bpf_disabled __read_mostly; 24 25 static LIST_HEAD(bpf_map_types); 26 27 static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) 28 { 29 struct bpf_map_type_list *tl; 30 struct bpf_map *map; 31 32 list_for_each_entry(tl, &bpf_map_types, list_node) { 33 if (tl->type == attr->map_type) { 34 map = tl->ops->map_alloc(attr); 35 if (IS_ERR(map)) 36 return map; 37 map->ops = tl->ops; 38 map->map_type = attr->map_type; 39 return map; 40 } 41 } 42 return ERR_PTR(-EINVAL); 43 } 44 45 /* boot time registration of different map implementations */ 46 void bpf_register_map_type(struct bpf_map_type_list *tl) 47 { 48 list_add(&tl->list_node, &bpf_map_types); 49 } 50 51 int bpf_map_precharge_memlock(u32 pages) 52 { 53 struct user_struct *user = get_current_user(); 54 unsigned long memlock_limit, cur; 55 56 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 57 cur = atomic_long_read(&user->locked_vm); 58 free_uid(user); 59 if (cur + pages > memlock_limit) 60 return -EPERM; 61 return 0; 62 } 63 64 static int bpf_map_charge_memlock(struct bpf_map *map) 65 { 66 struct user_struct *user = get_current_user(); 67 unsigned long memlock_limit; 68 69 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 70 71 atomic_long_add(map->pages, &user->locked_vm); 72 73 if (atomic_long_read(&user->locked_vm) > memlock_limit) { 74 atomic_long_sub(map->pages, &user->locked_vm); 75 free_uid(user); 76 return -EPERM; 77 } 78 map->user = user; 79 return 0; 80 } 81 82 static void bpf_map_uncharge_memlock(struct bpf_map *map) 83 { 84 struct user_struct *user = map->user; 85 86 atomic_long_sub(map->pages, &user->locked_vm); 87 free_uid(user); 88 } 89 90 /* called from workqueue */ 91 static void bpf_map_free_deferred(struct work_struct *work) 92 { 93 struct bpf_map *map = container_of(work, struct bpf_map, work); 94 95 bpf_map_uncharge_memlock(map); 96 /* implementation dependent freeing */ 97 map->ops->map_free(map); 98 } 99 100 static void bpf_map_put_uref(struct bpf_map *map) 101 { 102 if (atomic_dec_and_test(&map->usercnt)) { 103 if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY) 104 bpf_fd_array_map_clear(map); 105 } 106 } 107 108 /* decrement map refcnt and schedule it for freeing via workqueue 109 * (unrelying map implementation ops->map_free() might sleep) 110 */ 111 void bpf_map_put(struct bpf_map *map) 112 { 113 if (atomic_dec_and_test(&map->refcnt)) { 114 INIT_WORK(&map->work, bpf_map_free_deferred); 115 schedule_work(&map->work); 116 } 117 } 118 119 void bpf_map_put_with_uref(struct bpf_map *map) 120 { 121 bpf_map_put_uref(map); 122 bpf_map_put(map); 123 } 124 125 static int bpf_map_release(struct inode *inode, struct file *filp) 126 { 127 bpf_map_put_with_uref(filp->private_data); 128 return 0; 129 } 130 131 #ifdef CONFIG_PROC_FS 132 static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp) 133 { 134 const struct bpf_map *map = filp->private_data; 135 136 seq_printf(m, 137 "map_type:\t%u\n" 138 "key_size:\t%u\n" 139 "value_size:\t%u\n" 140 "max_entries:\t%u\n" 141 "map_flags:\t%#x\n", 142 map->map_type, 143 map->key_size, 144 map->value_size, 145 map->max_entries, 146 map->map_flags); 147 } 148 #endif 149 150 static const struct file_operations bpf_map_fops = { 151 #ifdef CONFIG_PROC_FS 152 .show_fdinfo = bpf_map_show_fdinfo, 153 #endif 154 .release = bpf_map_release, 155 }; 156 157 int bpf_map_new_fd(struct bpf_map *map) 158 { 159 return anon_inode_getfd("bpf-map", &bpf_map_fops, map, 160 O_RDWR | O_CLOEXEC); 161 } 162 163 /* helper macro to check that unused fields 'union bpf_attr' are zero */ 164 #define CHECK_ATTR(CMD) \ 165 memchr_inv((void *) &attr->CMD##_LAST_FIELD + \ 166 sizeof(attr->CMD##_LAST_FIELD), 0, \ 167 sizeof(*attr) - \ 168 offsetof(union bpf_attr, CMD##_LAST_FIELD) - \ 169 sizeof(attr->CMD##_LAST_FIELD)) != NULL 170 171 #define BPF_MAP_CREATE_LAST_FIELD map_flags 172 /* called via syscall */ 173 static int map_create(union bpf_attr *attr) 174 { 175 struct bpf_map *map; 176 int err; 177 178 err = CHECK_ATTR(BPF_MAP_CREATE); 179 if (err) 180 return -EINVAL; 181 182 /* find map type and init map: hashtable vs rbtree vs bloom vs ... */ 183 map = find_and_alloc_map(attr); 184 if (IS_ERR(map)) 185 return PTR_ERR(map); 186 187 atomic_set(&map->refcnt, 1); 188 atomic_set(&map->usercnt, 1); 189 190 err = bpf_map_charge_memlock(map); 191 if (err) 192 goto free_map; 193 194 err = bpf_map_new_fd(map); 195 if (err < 0) 196 /* failed to allocate fd */ 197 goto free_map; 198 199 return err; 200 201 free_map: 202 map->ops->map_free(map); 203 return err; 204 } 205 206 /* if error is returned, fd is released. 207 * On success caller should complete fd access with matching fdput() 208 */ 209 struct bpf_map *__bpf_map_get(struct fd f) 210 { 211 if (!f.file) 212 return ERR_PTR(-EBADF); 213 if (f.file->f_op != &bpf_map_fops) { 214 fdput(f); 215 return ERR_PTR(-EINVAL); 216 } 217 218 return f.file->private_data; 219 } 220 221 void bpf_map_inc(struct bpf_map *map, bool uref) 222 { 223 atomic_inc(&map->refcnt); 224 if (uref) 225 atomic_inc(&map->usercnt); 226 } 227 228 struct bpf_map *bpf_map_get_with_uref(u32 ufd) 229 { 230 struct fd f = fdget(ufd); 231 struct bpf_map *map; 232 233 map = __bpf_map_get(f); 234 if (IS_ERR(map)) 235 return map; 236 237 bpf_map_inc(map, true); 238 fdput(f); 239 240 return map; 241 } 242 243 /* helper to convert user pointers passed inside __aligned_u64 fields */ 244 static void __user *u64_to_ptr(__u64 val) 245 { 246 return (void __user *) (unsigned long) val; 247 } 248 249 int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value) 250 { 251 return -ENOTSUPP; 252 } 253 254 /* last field in 'union bpf_attr' used by this command */ 255 #define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value 256 257 static int map_lookup_elem(union bpf_attr *attr) 258 { 259 void __user *ukey = u64_to_ptr(attr->key); 260 void __user *uvalue = u64_to_ptr(attr->value); 261 int ufd = attr->map_fd; 262 struct bpf_map *map; 263 void *key, *value, *ptr; 264 u32 value_size; 265 struct fd f; 266 int err; 267 268 if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM)) 269 return -EINVAL; 270 271 f = fdget(ufd); 272 map = __bpf_map_get(f); 273 if (IS_ERR(map)) 274 return PTR_ERR(map); 275 276 err = -ENOMEM; 277 key = kmalloc(map->key_size, GFP_USER); 278 if (!key) 279 goto err_put; 280 281 err = -EFAULT; 282 if (copy_from_user(key, ukey, map->key_size) != 0) 283 goto free_key; 284 285 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 286 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) 287 value_size = round_up(map->value_size, 8) * num_possible_cpus(); 288 else 289 value_size = map->value_size; 290 291 err = -ENOMEM; 292 value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); 293 if (!value) 294 goto free_key; 295 296 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) { 297 err = bpf_percpu_hash_copy(map, key, value); 298 } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { 299 err = bpf_percpu_array_copy(map, key, value); 300 } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) { 301 err = bpf_stackmap_copy(map, key, value); 302 } else { 303 rcu_read_lock(); 304 ptr = map->ops->map_lookup_elem(map, key); 305 if (ptr) 306 memcpy(value, ptr, value_size); 307 rcu_read_unlock(); 308 err = ptr ? 0 : -ENOENT; 309 } 310 311 if (err) 312 goto free_value; 313 314 err = -EFAULT; 315 if (copy_to_user(uvalue, value, value_size) != 0) 316 goto free_value; 317 318 err = 0; 319 320 free_value: 321 kfree(value); 322 free_key: 323 kfree(key); 324 err_put: 325 fdput(f); 326 return err; 327 } 328 329 #define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags 330 331 static int map_update_elem(union bpf_attr *attr) 332 { 333 void __user *ukey = u64_to_ptr(attr->key); 334 void __user *uvalue = u64_to_ptr(attr->value); 335 int ufd = attr->map_fd; 336 struct bpf_map *map; 337 void *key, *value; 338 u32 value_size; 339 struct fd f; 340 int err; 341 342 if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM)) 343 return -EINVAL; 344 345 f = fdget(ufd); 346 map = __bpf_map_get(f); 347 if (IS_ERR(map)) 348 return PTR_ERR(map); 349 350 err = -ENOMEM; 351 key = kmalloc(map->key_size, GFP_USER); 352 if (!key) 353 goto err_put; 354 355 err = -EFAULT; 356 if (copy_from_user(key, ukey, map->key_size) != 0) 357 goto free_key; 358 359 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 360 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) 361 value_size = round_up(map->value_size, 8) * num_possible_cpus(); 362 else 363 value_size = map->value_size; 364 365 err = -ENOMEM; 366 value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); 367 if (!value) 368 goto free_key; 369 370 err = -EFAULT; 371 if (copy_from_user(value, uvalue, value_size) != 0) 372 goto free_value; 373 374 /* must increment bpf_prog_active to avoid kprobe+bpf triggering from 375 * inside bpf map update or delete otherwise deadlocks are possible 376 */ 377 preempt_disable(); 378 __this_cpu_inc(bpf_prog_active); 379 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) { 380 err = bpf_percpu_hash_update(map, key, value, attr->flags); 381 } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { 382 err = bpf_percpu_array_update(map, key, value, attr->flags); 383 } else { 384 rcu_read_lock(); 385 err = map->ops->map_update_elem(map, key, value, attr->flags); 386 rcu_read_unlock(); 387 } 388 __this_cpu_dec(bpf_prog_active); 389 preempt_enable(); 390 391 free_value: 392 kfree(value); 393 free_key: 394 kfree(key); 395 err_put: 396 fdput(f); 397 return err; 398 } 399 400 #define BPF_MAP_DELETE_ELEM_LAST_FIELD key 401 402 static int map_delete_elem(union bpf_attr *attr) 403 { 404 void __user *ukey = u64_to_ptr(attr->key); 405 int ufd = attr->map_fd; 406 struct bpf_map *map; 407 struct fd f; 408 void *key; 409 int err; 410 411 if (CHECK_ATTR(BPF_MAP_DELETE_ELEM)) 412 return -EINVAL; 413 414 f = fdget(ufd); 415 map = __bpf_map_get(f); 416 if (IS_ERR(map)) 417 return PTR_ERR(map); 418 419 err = -ENOMEM; 420 key = kmalloc(map->key_size, GFP_USER); 421 if (!key) 422 goto err_put; 423 424 err = -EFAULT; 425 if (copy_from_user(key, ukey, map->key_size) != 0) 426 goto free_key; 427 428 preempt_disable(); 429 __this_cpu_inc(bpf_prog_active); 430 rcu_read_lock(); 431 err = map->ops->map_delete_elem(map, key); 432 rcu_read_unlock(); 433 __this_cpu_dec(bpf_prog_active); 434 preempt_enable(); 435 436 free_key: 437 kfree(key); 438 err_put: 439 fdput(f); 440 return err; 441 } 442 443 /* last field in 'union bpf_attr' used by this command */ 444 #define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key 445 446 static int map_get_next_key(union bpf_attr *attr) 447 { 448 void __user *ukey = u64_to_ptr(attr->key); 449 void __user *unext_key = u64_to_ptr(attr->next_key); 450 int ufd = attr->map_fd; 451 struct bpf_map *map; 452 void *key, *next_key; 453 struct fd f; 454 int err; 455 456 if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY)) 457 return -EINVAL; 458 459 f = fdget(ufd); 460 map = __bpf_map_get(f); 461 if (IS_ERR(map)) 462 return PTR_ERR(map); 463 464 err = -ENOMEM; 465 key = kmalloc(map->key_size, GFP_USER); 466 if (!key) 467 goto err_put; 468 469 err = -EFAULT; 470 if (copy_from_user(key, ukey, map->key_size) != 0) 471 goto free_key; 472 473 err = -ENOMEM; 474 next_key = kmalloc(map->key_size, GFP_USER); 475 if (!next_key) 476 goto free_key; 477 478 rcu_read_lock(); 479 err = map->ops->map_get_next_key(map, key, next_key); 480 rcu_read_unlock(); 481 if (err) 482 goto free_next_key; 483 484 err = -EFAULT; 485 if (copy_to_user(unext_key, next_key, map->key_size) != 0) 486 goto free_next_key; 487 488 err = 0; 489 490 free_next_key: 491 kfree(next_key); 492 free_key: 493 kfree(key); 494 err_put: 495 fdput(f); 496 return err; 497 } 498 499 static LIST_HEAD(bpf_prog_types); 500 501 static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog) 502 { 503 struct bpf_prog_type_list *tl; 504 505 list_for_each_entry(tl, &bpf_prog_types, list_node) { 506 if (tl->type == type) { 507 prog->aux->ops = tl->ops; 508 prog->type = type; 509 return 0; 510 } 511 } 512 513 return -EINVAL; 514 } 515 516 void bpf_register_prog_type(struct bpf_prog_type_list *tl) 517 { 518 list_add(&tl->list_node, &bpf_prog_types); 519 } 520 521 /* fixup insn->imm field of bpf_call instructions: 522 * if (insn->imm == BPF_FUNC_map_lookup_elem) 523 * insn->imm = bpf_map_lookup_elem - __bpf_call_base; 524 * else if (insn->imm == BPF_FUNC_map_update_elem) 525 * insn->imm = bpf_map_update_elem - __bpf_call_base; 526 * else ... 527 * 528 * this function is called after eBPF program passed verification 529 */ 530 static void fixup_bpf_calls(struct bpf_prog *prog) 531 { 532 const struct bpf_func_proto *fn; 533 int i; 534 535 for (i = 0; i < prog->len; i++) { 536 struct bpf_insn *insn = &prog->insnsi[i]; 537 538 if (insn->code == (BPF_JMP | BPF_CALL)) { 539 /* we reach here when program has bpf_call instructions 540 * and it passed bpf_check(), means that 541 * ops->get_func_proto must have been supplied, check it 542 */ 543 BUG_ON(!prog->aux->ops->get_func_proto); 544 545 if (insn->imm == BPF_FUNC_get_route_realm) 546 prog->dst_needed = 1; 547 if (insn->imm == BPF_FUNC_get_prandom_u32) 548 bpf_user_rnd_init_once(); 549 if (insn->imm == BPF_FUNC_tail_call) { 550 /* mark bpf_tail_call as different opcode 551 * to avoid conditional branch in 552 * interpeter for every normal call 553 * and to prevent accidental JITing by 554 * JIT compiler that doesn't support 555 * bpf_tail_call yet 556 */ 557 insn->imm = 0; 558 insn->code |= BPF_X; 559 continue; 560 } 561 562 fn = prog->aux->ops->get_func_proto(insn->imm); 563 /* all functions that have prototype and verifier allowed 564 * programs to call them, must be real in-kernel functions 565 */ 566 BUG_ON(!fn->func); 567 insn->imm = fn->func - __bpf_call_base; 568 } 569 } 570 } 571 572 /* drop refcnt on maps used by eBPF program and free auxilary data */ 573 static void free_used_maps(struct bpf_prog_aux *aux) 574 { 575 int i; 576 577 for (i = 0; i < aux->used_map_cnt; i++) 578 bpf_map_put(aux->used_maps[i]); 579 580 kfree(aux->used_maps); 581 } 582 583 static int bpf_prog_charge_memlock(struct bpf_prog *prog) 584 { 585 struct user_struct *user = get_current_user(); 586 unsigned long memlock_limit; 587 588 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 589 590 atomic_long_add(prog->pages, &user->locked_vm); 591 if (atomic_long_read(&user->locked_vm) > memlock_limit) { 592 atomic_long_sub(prog->pages, &user->locked_vm); 593 free_uid(user); 594 return -EPERM; 595 } 596 prog->aux->user = user; 597 return 0; 598 } 599 600 static void bpf_prog_uncharge_memlock(struct bpf_prog *prog) 601 { 602 struct user_struct *user = prog->aux->user; 603 604 atomic_long_sub(prog->pages, &user->locked_vm); 605 free_uid(user); 606 } 607 608 static void __prog_put_common(struct rcu_head *rcu) 609 { 610 struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu); 611 612 free_used_maps(aux); 613 bpf_prog_uncharge_memlock(aux->prog); 614 bpf_prog_free(aux->prog); 615 } 616 617 /* version of bpf_prog_put() that is called after a grace period */ 618 void bpf_prog_put_rcu(struct bpf_prog *prog) 619 { 620 if (atomic_dec_and_test(&prog->aux->refcnt)) 621 call_rcu(&prog->aux->rcu, __prog_put_common); 622 } 623 624 void bpf_prog_put(struct bpf_prog *prog) 625 { 626 if (atomic_dec_and_test(&prog->aux->refcnt)) 627 __prog_put_common(&prog->aux->rcu); 628 } 629 EXPORT_SYMBOL_GPL(bpf_prog_put); 630 631 static int bpf_prog_release(struct inode *inode, struct file *filp) 632 { 633 struct bpf_prog *prog = filp->private_data; 634 635 bpf_prog_put_rcu(prog); 636 return 0; 637 } 638 639 static const struct file_operations bpf_prog_fops = { 640 .release = bpf_prog_release, 641 }; 642 643 int bpf_prog_new_fd(struct bpf_prog *prog) 644 { 645 return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog, 646 O_RDWR | O_CLOEXEC); 647 } 648 649 static struct bpf_prog *__bpf_prog_get(struct fd f) 650 { 651 if (!f.file) 652 return ERR_PTR(-EBADF); 653 if (f.file->f_op != &bpf_prog_fops) { 654 fdput(f); 655 return ERR_PTR(-EINVAL); 656 } 657 658 return f.file->private_data; 659 } 660 661 /* called by sockets/tracing/seccomp before attaching program to an event 662 * pairs with bpf_prog_put() 663 */ 664 struct bpf_prog *bpf_prog_get(u32 ufd) 665 { 666 struct fd f = fdget(ufd); 667 struct bpf_prog *prog; 668 669 prog = __bpf_prog_get(f); 670 if (IS_ERR(prog)) 671 return prog; 672 673 atomic_inc(&prog->aux->refcnt); 674 fdput(f); 675 676 return prog; 677 } 678 EXPORT_SYMBOL_GPL(bpf_prog_get); 679 680 /* last field in 'union bpf_attr' used by this command */ 681 #define BPF_PROG_LOAD_LAST_FIELD kern_version 682 683 static int bpf_prog_load(union bpf_attr *attr) 684 { 685 enum bpf_prog_type type = attr->prog_type; 686 struct bpf_prog *prog; 687 int err; 688 char license[128]; 689 bool is_gpl; 690 691 if (CHECK_ATTR(BPF_PROG_LOAD)) 692 return -EINVAL; 693 694 /* copy eBPF program license from user space */ 695 if (strncpy_from_user(license, u64_to_ptr(attr->license), 696 sizeof(license) - 1) < 0) 697 return -EFAULT; 698 license[sizeof(license) - 1] = 0; 699 700 /* eBPF programs must be GPL compatible to use GPL-ed functions */ 701 is_gpl = license_is_gpl_compatible(license); 702 703 if (attr->insn_cnt >= BPF_MAXINSNS) 704 return -EINVAL; 705 706 if (type == BPF_PROG_TYPE_KPROBE && 707 attr->kern_version != LINUX_VERSION_CODE) 708 return -EINVAL; 709 710 if (type != BPF_PROG_TYPE_SOCKET_FILTER && !capable(CAP_SYS_ADMIN)) 711 return -EPERM; 712 713 /* plain bpf_prog allocation */ 714 prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER); 715 if (!prog) 716 return -ENOMEM; 717 718 err = bpf_prog_charge_memlock(prog); 719 if (err) 720 goto free_prog_nouncharge; 721 722 prog->len = attr->insn_cnt; 723 724 err = -EFAULT; 725 if (copy_from_user(prog->insns, u64_to_ptr(attr->insns), 726 prog->len * sizeof(struct bpf_insn)) != 0) 727 goto free_prog; 728 729 prog->orig_prog = NULL; 730 prog->jited = 0; 731 732 atomic_set(&prog->aux->refcnt, 1); 733 prog->gpl_compatible = is_gpl ? 1 : 0; 734 735 /* find program type: socket_filter vs tracing_filter */ 736 err = find_prog_type(type, prog); 737 if (err < 0) 738 goto free_prog; 739 740 /* run eBPF verifier */ 741 err = bpf_check(&prog, attr); 742 if (err < 0) 743 goto free_used_maps; 744 745 /* fixup BPF_CALL->imm field */ 746 fixup_bpf_calls(prog); 747 748 /* eBPF program is ready to be JITed */ 749 err = bpf_prog_select_runtime(prog); 750 if (err < 0) 751 goto free_used_maps; 752 753 err = bpf_prog_new_fd(prog); 754 if (err < 0) 755 /* failed to allocate fd */ 756 goto free_used_maps; 757 758 return err; 759 760 free_used_maps: 761 free_used_maps(prog->aux); 762 free_prog: 763 bpf_prog_uncharge_memlock(prog); 764 free_prog_nouncharge: 765 bpf_prog_free(prog); 766 return err; 767 } 768 769 #define BPF_OBJ_LAST_FIELD bpf_fd 770 771 static int bpf_obj_pin(const union bpf_attr *attr) 772 { 773 if (CHECK_ATTR(BPF_OBJ)) 774 return -EINVAL; 775 776 return bpf_obj_pin_user(attr->bpf_fd, u64_to_ptr(attr->pathname)); 777 } 778 779 static int bpf_obj_get(const union bpf_attr *attr) 780 { 781 if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0) 782 return -EINVAL; 783 784 return bpf_obj_get_user(u64_to_ptr(attr->pathname)); 785 } 786 787 SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) 788 { 789 union bpf_attr attr = {}; 790 int err; 791 792 if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled) 793 return -EPERM; 794 795 if (!access_ok(VERIFY_READ, uattr, 1)) 796 return -EFAULT; 797 798 if (size > PAGE_SIZE) /* silly large */ 799 return -E2BIG; 800 801 /* If we're handed a bigger struct than we know of, 802 * ensure all the unknown bits are 0 - i.e. new 803 * user-space does not rely on any kernel feature 804 * extensions we dont know about yet. 805 */ 806 if (size > sizeof(attr)) { 807 unsigned char __user *addr; 808 unsigned char __user *end; 809 unsigned char val; 810 811 addr = (void __user *)uattr + sizeof(attr); 812 end = (void __user *)uattr + size; 813 814 for (; addr < end; addr++) { 815 err = get_user(val, addr); 816 if (err) 817 return err; 818 if (val) 819 return -E2BIG; 820 } 821 size = sizeof(attr); 822 } 823 824 /* copy attributes from user space, may be less than sizeof(bpf_attr) */ 825 if (copy_from_user(&attr, uattr, size) != 0) 826 return -EFAULT; 827 828 switch (cmd) { 829 case BPF_MAP_CREATE: 830 err = map_create(&attr); 831 break; 832 case BPF_MAP_LOOKUP_ELEM: 833 err = map_lookup_elem(&attr); 834 break; 835 case BPF_MAP_UPDATE_ELEM: 836 err = map_update_elem(&attr); 837 break; 838 case BPF_MAP_DELETE_ELEM: 839 err = map_delete_elem(&attr); 840 break; 841 case BPF_MAP_GET_NEXT_KEY: 842 err = map_get_next_key(&attr); 843 break; 844 case BPF_PROG_LOAD: 845 err = bpf_prog_load(&attr); 846 break; 847 case BPF_OBJ_PIN: 848 err = bpf_obj_pin(&attr); 849 break; 850 case BPF_OBJ_GET: 851 err = bpf_obj_get(&attr); 852 break; 853 default: 854 err = -EINVAL; 855 break; 856 } 857 858 return err; 859 } 860