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 /* prog's and map's refcnt limit */ 222 #define BPF_MAX_REFCNT 32768 223 224 struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref) 225 { 226 if (atomic_inc_return(&map->refcnt) > BPF_MAX_REFCNT) { 227 atomic_dec(&map->refcnt); 228 return ERR_PTR(-EBUSY); 229 } 230 if (uref) 231 atomic_inc(&map->usercnt); 232 return map; 233 } 234 235 struct bpf_map *bpf_map_get_with_uref(u32 ufd) 236 { 237 struct fd f = fdget(ufd); 238 struct bpf_map *map; 239 240 map = __bpf_map_get(f); 241 if (IS_ERR(map)) 242 return map; 243 244 map = bpf_map_inc(map, true); 245 fdput(f); 246 247 return map; 248 } 249 250 /* helper to convert user pointers passed inside __aligned_u64 fields */ 251 static void __user *u64_to_ptr(__u64 val) 252 { 253 return (void __user *) (unsigned long) val; 254 } 255 256 int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value) 257 { 258 return -ENOTSUPP; 259 } 260 261 /* last field in 'union bpf_attr' used by this command */ 262 #define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value 263 264 static int map_lookup_elem(union bpf_attr *attr) 265 { 266 void __user *ukey = u64_to_ptr(attr->key); 267 void __user *uvalue = u64_to_ptr(attr->value); 268 int ufd = attr->map_fd; 269 struct bpf_map *map; 270 void *key, *value, *ptr; 271 u32 value_size; 272 struct fd f; 273 int err; 274 275 if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM)) 276 return -EINVAL; 277 278 f = fdget(ufd); 279 map = __bpf_map_get(f); 280 if (IS_ERR(map)) 281 return PTR_ERR(map); 282 283 err = -ENOMEM; 284 key = kmalloc(map->key_size, GFP_USER); 285 if (!key) 286 goto err_put; 287 288 err = -EFAULT; 289 if (copy_from_user(key, ukey, map->key_size) != 0) 290 goto free_key; 291 292 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 293 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) 294 value_size = round_up(map->value_size, 8) * num_possible_cpus(); 295 else 296 value_size = map->value_size; 297 298 err = -ENOMEM; 299 value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); 300 if (!value) 301 goto free_key; 302 303 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) { 304 err = bpf_percpu_hash_copy(map, key, value); 305 } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { 306 err = bpf_percpu_array_copy(map, key, value); 307 } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) { 308 err = bpf_stackmap_copy(map, key, value); 309 } else { 310 rcu_read_lock(); 311 ptr = map->ops->map_lookup_elem(map, key); 312 if (ptr) 313 memcpy(value, ptr, value_size); 314 rcu_read_unlock(); 315 err = ptr ? 0 : -ENOENT; 316 } 317 318 if (err) 319 goto free_value; 320 321 err = -EFAULT; 322 if (copy_to_user(uvalue, value, value_size) != 0) 323 goto free_value; 324 325 err = 0; 326 327 free_value: 328 kfree(value); 329 free_key: 330 kfree(key); 331 err_put: 332 fdput(f); 333 return err; 334 } 335 336 #define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags 337 338 static int map_update_elem(union bpf_attr *attr) 339 { 340 void __user *ukey = u64_to_ptr(attr->key); 341 void __user *uvalue = u64_to_ptr(attr->value); 342 int ufd = attr->map_fd; 343 struct bpf_map *map; 344 void *key, *value; 345 u32 value_size; 346 struct fd f; 347 int err; 348 349 if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM)) 350 return -EINVAL; 351 352 f = fdget(ufd); 353 map = __bpf_map_get(f); 354 if (IS_ERR(map)) 355 return PTR_ERR(map); 356 357 err = -ENOMEM; 358 key = kmalloc(map->key_size, GFP_USER); 359 if (!key) 360 goto err_put; 361 362 err = -EFAULT; 363 if (copy_from_user(key, ukey, map->key_size) != 0) 364 goto free_key; 365 366 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || 367 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) 368 value_size = round_up(map->value_size, 8) * num_possible_cpus(); 369 else 370 value_size = map->value_size; 371 372 err = -ENOMEM; 373 value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); 374 if (!value) 375 goto free_key; 376 377 err = -EFAULT; 378 if (copy_from_user(value, uvalue, value_size) != 0) 379 goto free_value; 380 381 /* must increment bpf_prog_active to avoid kprobe+bpf triggering from 382 * inside bpf map update or delete otherwise deadlocks are possible 383 */ 384 preempt_disable(); 385 __this_cpu_inc(bpf_prog_active); 386 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) { 387 err = bpf_percpu_hash_update(map, key, value, attr->flags); 388 } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { 389 err = bpf_percpu_array_update(map, key, value, attr->flags); 390 } else { 391 rcu_read_lock(); 392 err = map->ops->map_update_elem(map, key, value, attr->flags); 393 rcu_read_unlock(); 394 } 395 __this_cpu_dec(bpf_prog_active); 396 preempt_enable(); 397 398 free_value: 399 kfree(value); 400 free_key: 401 kfree(key); 402 err_put: 403 fdput(f); 404 return err; 405 } 406 407 #define BPF_MAP_DELETE_ELEM_LAST_FIELD key 408 409 static int map_delete_elem(union bpf_attr *attr) 410 { 411 void __user *ukey = u64_to_ptr(attr->key); 412 int ufd = attr->map_fd; 413 struct bpf_map *map; 414 struct fd f; 415 void *key; 416 int err; 417 418 if (CHECK_ATTR(BPF_MAP_DELETE_ELEM)) 419 return -EINVAL; 420 421 f = fdget(ufd); 422 map = __bpf_map_get(f); 423 if (IS_ERR(map)) 424 return PTR_ERR(map); 425 426 err = -ENOMEM; 427 key = kmalloc(map->key_size, GFP_USER); 428 if (!key) 429 goto err_put; 430 431 err = -EFAULT; 432 if (copy_from_user(key, ukey, map->key_size) != 0) 433 goto free_key; 434 435 preempt_disable(); 436 __this_cpu_inc(bpf_prog_active); 437 rcu_read_lock(); 438 err = map->ops->map_delete_elem(map, key); 439 rcu_read_unlock(); 440 __this_cpu_dec(bpf_prog_active); 441 preempt_enable(); 442 443 free_key: 444 kfree(key); 445 err_put: 446 fdput(f); 447 return err; 448 } 449 450 /* last field in 'union bpf_attr' used by this command */ 451 #define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key 452 453 static int map_get_next_key(union bpf_attr *attr) 454 { 455 void __user *ukey = u64_to_ptr(attr->key); 456 void __user *unext_key = u64_to_ptr(attr->next_key); 457 int ufd = attr->map_fd; 458 struct bpf_map *map; 459 void *key, *next_key; 460 struct fd f; 461 int err; 462 463 if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY)) 464 return -EINVAL; 465 466 f = fdget(ufd); 467 map = __bpf_map_get(f); 468 if (IS_ERR(map)) 469 return PTR_ERR(map); 470 471 err = -ENOMEM; 472 key = kmalloc(map->key_size, GFP_USER); 473 if (!key) 474 goto err_put; 475 476 err = -EFAULT; 477 if (copy_from_user(key, ukey, map->key_size) != 0) 478 goto free_key; 479 480 err = -ENOMEM; 481 next_key = kmalloc(map->key_size, GFP_USER); 482 if (!next_key) 483 goto free_key; 484 485 rcu_read_lock(); 486 err = map->ops->map_get_next_key(map, key, next_key); 487 rcu_read_unlock(); 488 if (err) 489 goto free_next_key; 490 491 err = -EFAULT; 492 if (copy_to_user(unext_key, next_key, map->key_size) != 0) 493 goto free_next_key; 494 495 err = 0; 496 497 free_next_key: 498 kfree(next_key); 499 free_key: 500 kfree(key); 501 err_put: 502 fdput(f); 503 return err; 504 } 505 506 static LIST_HEAD(bpf_prog_types); 507 508 static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog) 509 { 510 struct bpf_prog_type_list *tl; 511 512 list_for_each_entry(tl, &bpf_prog_types, list_node) { 513 if (tl->type == type) { 514 prog->aux->ops = tl->ops; 515 prog->type = type; 516 return 0; 517 } 518 } 519 520 return -EINVAL; 521 } 522 523 void bpf_register_prog_type(struct bpf_prog_type_list *tl) 524 { 525 list_add(&tl->list_node, &bpf_prog_types); 526 } 527 528 /* fixup insn->imm field of bpf_call instructions: 529 * if (insn->imm == BPF_FUNC_map_lookup_elem) 530 * insn->imm = bpf_map_lookup_elem - __bpf_call_base; 531 * else if (insn->imm == BPF_FUNC_map_update_elem) 532 * insn->imm = bpf_map_update_elem - __bpf_call_base; 533 * else ... 534 * 535 * this function is called after eBPF program passed verification 536 */ 537 static void fixup_bpf_calls(struct bpf_prog *prog) 538 { 539 const struct bpf_func_proto *fn; 540 int i; 541 542 for (i = 0; i < prog->len; i++) { 543 struct bpf_insn *insn = &prog->insnsi[i]; 544 545 if (insn->code == (BPF_JMP | BPF_CALL)) { 546 /* we reach here when program has bpf_call instructions 547 * and it passed bpf_check(), means that 548 * ops->get_func_proto must have been supplied, check it 549 */ 550 BUG_ON(!prog->aux->ops->get_func_proto); 551 552 if (insn->imm == BPF_FUNC_get_route_realm) 553 prog->dst_needed = 1; 554 if (insn->imm == BPF_FUNC_get_prandom_u32) 555 bpf_user_rnd_init_once(); 556 if (insn->imm == BPF_FUNC_tail_call) { 557 /* mark bpf_tail_call as different opcode 558 * to avoid conditional branch in 559 * interpeter for every normal call 560 * and to prevent accidental JITing by 561 * JIT compiler that doesn't support 562 * bpf_tail_call yet 563 */ 564 insn->imm = 0; 565 insn->code |= BPF_X; 566 continue; 567 } 568 569 fn = prog->aux->ops->get_func_proto(insn->imm); 570 /* all functions that have prototype and verifier allowed 571 * programs to call them, must be real in-kernel functions 572 */ 573 BUG_ON(!fn->func); 574 insn->imm = fn->func - __bpf_call_base; 575 } 576 } 577 } 578 579 /* drop refcnt on maps used by eBPF program and free auxilary data */ 580 static void free_used_maps(struct bpf_prog_aux *aux) 581 { 582 int i; 583 584 for (i = 0; i < aux->used_map_cnt; i++) 585 bpf_map_put(aux->used_maps[i]); 586 587 kfree(aux->used_maps); 588 } 589 590 static int bpf_prog_charge_memlock(struct bpf_prog *prog) 591 { 592 struct user_struct *user = get_current_user(); 593 unsigned long memlock_limit; 594 595 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 596 597 atomic_long_add(prog->pages, &user->locked_vm); 598 if (atomic_long_read(&user->locked_vm) > memlock_limit) { 599 atomic_long_sub(prog->pages, &user->locked_vm); 600 free_uid(user); 601 return -EPERM; 602 } 603 prog->aux->user = user; 604 return 0; 605 } 606 607 static void bpf_prog_uncharge_memlock(struct bpf_prog *prog) 608 { 609 struct user_struct *user = prog->aux->user; 610 611 atomic_long_sub(prog->pages, &user->locked_vm); 612 free_uid(user); 613 } 614 615 static void __prog_put_common(struct rcu_head *rcu) 616 { 617 struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu); 618 619 free_used_maps(aux); 620 bpf_prog_uncharge_memlock(aux->prog); 621 bpf_prog_free(aux->prog); 622 } 623 624 /* version of bpf_prog_put() that is called after a grace period */ 625 void bpf_prog_put_rcu(struct bpf_prog *prog) 626 { 627 if (atomic_dec_and_test(&prog->aux->refcnt)) 628 call_rcu(&prog->aux->rcu, __prog_put_common); 629 } 630 631 void bpf_prog_put(struct bpf_prog *prog) 632 { 633 if (atomic_dec_and_test(&prog->aux->refcnt)) 634 __prog_put_common(&prog->aux->rcu); 635 } 636 EXPORT_SYMBOL_GPL(bpf_prog_put); 637 638 static int bpf_prog_release(struct inode *inode, struct file *filp) 639 { 640 struct bpf_prog *prog = filp->private_data; 641 642 bpf_prog_put_rcu(prog); 643 return 0; 644 } 645 646 static const struct file_operations bpf_prog_fops = { 647 .release = bpf_prog_release, 648 }; 649 650 int bpf_prog_new_fd(struct bpf_prog *prog) 651 { 652 return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog, 653 O_RDWR | O_CLOEXEC); 654 } 655 656 static struct bpf_prog *__bpf_prog_get(struct fd f) 657 { 658 if (!f.file) 659 return ERR_PTR(-EBADF); 660 if (f.file->f_op != &bpf_prog_fops) { 661 fdput(f); 662 return ERR_PTR(-EINVAL); 663 } 664 665 return f.file->private_data; 666 } 667 668 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) 669 { 670 if (atomic_inc_return(&prog->aux->refcnt) > BPF_MAX_REFCNT) { 671 atomic_dec(&prog->aux->refcnt); 672 return ERR_PTR(-EBUSY); 673 } 674 return prog; 675 } 676 677 /* called by sockets/tracing/seccomp before attaching program to an event 678 * pairs with bpf_prog_put() 679 */ 680 struct bpf_prog *bpf_prog_get(u32 ufd) 681 { 682 struct fd f = fdget(ufd); 683 struct bpf_prog *prog; 684 685 prog = __bpf_prog_get(f); 686 if (IS_ERR(prog)) 687 return prog; 688 689 prog = bpf_prog_inc(prog); 690 fdput(f); 691 692 return prog; 693 } 694 EXPORT_SYMBOL_GPL(bpf_prog_get); 695 696 /* last field in 'union bpf_attr' used by this command */ 697 #define BPF_PROG_LOAD_LAST_FIELD kern_version 698 699 static int bpf_prog_load(union bpf_attr *attr) 700 { 701 enum bpf_prog_type type = attr->prog_type; 702 struct bpf_prog *prog; 703 int err; 704 char license[128]; 705 bool is_gpl; 706 707 if (CHECK_ATTR(BPF_PROG_LOAD)) 708 return -EINVAL; 709 710 /* copy eBPF program license from user space */ 711 if (strncpy_from_user(license, u64_to_ptr(attr->license), 712 sizeof(license) - 1) < 0) 713 return -EFAULT; 714 license[sizeof(license) - 1] = 0; 715 716 /* eBPF programs must be GPL compatible to use GPL-ed functions */ 717 is_gpl = license_is_gpl_compatible(license); 718 719 if (attr->insn_cnt >= BPF_MAXINSNS) 720 return -EINVAL; 721 722 if (type == BPF_PROG_TYPE_KPROBE && 723 attr->kern_version != LINUX_VERSION_CODE) 724 return -EINVAL; 725 726 if (type != BPF_PROG_TYPE_SOCKET_FILTER && !capable(CAP_SYS_ADMIN)) 727 return -EPERM; 728 729 /* plain bpf_prog allocation */ 730 prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER); 731 if (!prog) 732 return -ENOMEM; 733 734 err = bpf_prog_charge_memlock(prog); 735 if (err) 736 goto free_prog_nouncharge; 737 738 prog->len = attr->insn_cnt; 739 740 err = -EFAULT; 741 if (copy_from_user(prog->insns, u64_to_ptr(attr->insns), 742 prog->len * sizeof(struct bpf_insn)) != 0) 743 goto free_prog; 744 745 prog->orig_prog = NULL; 746 prog->jited = 0; 747 748 atomic_set(&prog->aux->refcnt, 1); 749 prog->gpl_compatible = is_gpl ? 1 : 0; 750 751 /* find program type: socket_filter vs tracing_filter */ 752 err = find_prog_type(type, prog); 753 if (err < 0) 754 goto free_prog; 755 756 /* run eBPF verifier */ 757 err = bpf_check(&prog, attr); 758 if (err < 0) 759 goto free_used_maps; 760 761 /* fixup BPF_CALL->imm field */ 762 fixup_bpf_calls(prog); 763 764 /* eBPF program is ready to be JITed */ 765 err = bpf_prog_select_runtime(prog); 766 if (err < 0) 767 goto free_used_maps; 768 769 err = bpf_prog_new_fd(prog); 770 if (err < 0) 771 /* failed to allocate fd */ 772 goto free_used_maps; 773 774 return err; 775 776 free_used_maps: 777 free_used_maps(prog->aux); 778 free_prog: 779 bpf_prog_uncharge_memlock(prog); 780 free_prog_nouncharge: 781 bpf_prog_free(prog); 782 return err; 783 } 784 785 #define BPF_OBJ_LAST_FIELD bpf_fd 786 787 static int bpf_obj_pin(const union bpf_attr *attr) 788 { 789 if (CHECK_ATTR(BPF_OBJ)) 790 return -EINVAL; 791 792 return bpf_obj_pin_user(attr->bpf_fd, u64_to_ptr(attr->pathname)); 793 } 794 795 static int bpf_obj_get(const union bpf_attr *attr) 796 { 797 if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0) 798 return -EINVAL; 799 800 return bpf_obj_get_user(u64_to_ptr(attr->pathname)); 801 } 802 803 SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) 804 { 805 union bpf_attr attr = {}; 806 int err; 807 808 if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled) 809 return -EPERM; 810 811 if (!access_ok(VERIFY_READ, uattr, 1)) 812 return -EFAULT; 813 814 if (size > PAGE_SIZE) /* silly large */ 815 return -E2BIG; 816 817 /* If we're handed a bigger struct than we know of, 818 * ensure all the unknown bits are 0 - i.e. new 819 * user-space does not rely on any kernel feature 820 * extensions we dont know about yet. 821 */ 822 if (size > sizeof(attr)) { 823 unsigned char __user *addr; 824 unsigned char __user *end; 825 unsigned char val; 826 827 addr = (void __user *)uattr + sizeof(attr); 828 end = (void __user *)uattr + size; 829 830 for (; addr < end; addr++) { 831 err = get_user(val, addr); 832 if (err) 833 return err; 834 if (val) 835 return -E2BIG; 836 } 837 size = sizeof(attr); 838 } 839 840 /* copy attributes from user space, may be less than sizeof(bpf_attr) */ 841 if (copy_from_user(&attr, uattr, size) != 0) 842 return -EFAULT; 843 844 switch (cmd) { 845 case BPF_MAP_CREATE: 846 err = map_create(&attr); 847 break; 848 case BPF_MAP_LOOKUP_ELEM: 849 err = map_lookup_elem(&attr); 850 break; 851 case BPF_MAP_UPDATE_ELEM: 852 err = map_update_elem(&attr); 853 break; 854 case BPF_MAP_DELETE_ELEM: 855 err = map_delete_elem(&attr); 856 break; 857 case BPF_MAP_GET_NEXT_KEY: 858 err = map_get_next_key(&attr); 859 break; 860 case BPF_PROG_LOAD: 861 err = bpf_prog_load(&attr); 862 break; 863 case BPF_OBJ_PIN: 864 err = bpf_obj_pin(&attr); 865 break; 866 case BPF_OBJ_GET: 867 err = bpf_obj_get(&attr); 868 break; 869 default: 870 err = -EINVAL; 871 break; 872 } 873 874 return err; 875 } 876