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