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_tail_call) { 583 /* mark bpf_tail_call as different opcode 584 * to avoid conditional branch in 585 * interpeter for every normal call 586 * and to prevent accidental JITing by 587 * JIT compiler that doesn't support 588 * bpf_tail_call yet 589 */ 590 insn->imm = 0; 591 insn->code |= BPF_X; 592 continue; 593 } 594 595 fn = prog->aux->ops->get_func_proto(insn->imm); 596 /* all functions that have prototype and verifier allowed 597 * programs to call them, must be real in-kernel functions 598 */ 599 BUG_ON(!fn->func); 600 insn->imm = fn->func - __bpf_call_base; 601 } 602 } 603 } 604 605 /* drop refcnt on maps used by eBPF program and free auxilary data */ 606 static void free_used_maps(struct bpf_prog_aux *aux) 607 { 608 int i; 609 610 for (i = 0; i < aux->used_map_cnt; i++) 611 bpf_map_put(aux->used_maps[i]); 612 613 kfree(aux->used_maps); 614 } 615 616 static int bpf_prog_charge_memlock(struct bpf_prog *prog) 617 { 618 struct user_struct *user = get_current_user(); 619 unsigned long memlock_limit; 620 621 memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 622 623 atomic_long_add(prog->pages, &user->locked_vm); 624 if (atomic_long_read(&user->locked_vm) > memlock_limit) { 625 atomic_long_sub(prog->pages, &user->locked_vm); 626 free_uid(user); 627 return -EPERM; 628 } 629 prog->aux->user = user; 630 return 0; 631 } 632 633 static void bpf_prog_uncharge_memlock(struct bpf_prog *prog) 634 { 635 struct user_struct *user = prog->aux->user; 636 637 atomic_long_sub(prog->pages, &user->locked_vm); 638 free_uid(user); 639 } 640 641 static void __bpf_prog_put_rcu(struct rcu_head *rcu) 642 { 643 struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu); 644 645 free_used_maps(aux); 646 bpf_prog_uncharge_memlock(aux->prog); 647 bpf_prog_free(aux->prog); 648 } 649 650 void bpf_prog_put(struct bpf_prog *prog) 651 { 652 if (atomic_dec_and_test(&prog->aux->refcnt)) 653 call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu); 654 } 655 EXPORT_SYMBOL_GPL(bpf_prog_put); 656 657 static int bpf_prog_release(struct inode *inode, struct file *filp) 658 { 659 struct bpf_prog *prog = filp->private_data; 660 661 bpf_prog_put(prog); 662 return 0; 663 } 664 665 static const struct file_operations bpf_prog_fops = { 666 .release = bpf_prog_release, 667 }; 668 669 int bpf_prog_new_fd(struct bpf_prog *prog) 670 { 671 return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog, 672 O_RDWR | O_CLOEXEC); 673 } 674 675 static struct bpf_prog *____bpf_prog_get(struct fd f) 676 { 677 if (!f.file) 678 return ERR_PTR(-EBADF); 679 if (f.file->f_op != &bpf_prog_fops) { 680 fdput(f); 681 return ERR_PTR(-EINVAL); 682 } 683 684 return f.file->private_data; 685 } 686 687 struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i) 688 { 689 if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) { 690 atomic_sub(i, &prog->aux->refcnt); 691 return ERR_PTR(-EBUSY); 692 } 693 return prog; 694 } 695 EXPORT_SYMBOL_GPL(bpf_prog_add); 696 697 void bpf_prog_sub(struct bpf_prog *prog, int i) 698 { 699 /* Only to be used for undoing previous bpf_prog_add() in some 700 * error path. We still know that another entity in our call 701 * path holds a reference to the program, thus atomic_sub() can 702 * be safely used in such cases! 703 */ 704 WARN_ON(atomic_sub_return(i, &prog->aux->refcnt) == 0); 705 } 706 EXPORT_SYMBOL_GPL(bpf_prog_sub); 707 708 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) 709 { 710 return bpf_prog_add(prog, 1); 711 } 712 EXPORT_SYMBOL_GPL(bpf_prog_inc); 713 714 static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type) 715 { 716 struct fd f = fdget(ufd); 717 struct bpf_prog *prog; 718 719 prog = ____bpf_prog_get(f); 720 if (IS_ERR(prog)) 721 return prog; 722 if (type && prog->type != *type) { 723 prog = ERR_PTR(-EINVAL); 724 goto out; 725 } 726 727 prog = bpf_prog_inc(prog); 728 out: 729 fdput(f); 730 return prog; 731 } 732 733 struct bpf_prog *bpf_prog_get(u32 ufd) 734 { 735 return __bpf_prog_get(ufd, NULL); 736 } 737 738 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type) 739 { 740 return __bpf_prog_get(ufd, &type); 741 } 742 EXPORT_SYMBOL_GPL(bpf_prog_get_type); 743 744 /* last field in 'union bpf_attr' used by this command */ 745 #define BPF_PROG_LOAD_LAST_FIELD kern_version 746 747 static int bpf_prog_load(union bpf_attr *attr) 748 { 749 enum bpf_prog_type type = attr->prog_type; 750 struct bpf_prog *prog; 751 int err; 752 char license[128]; 753 bool is_gpl; 754 755 if (CHECK_ATTR(BPF_PROG_LOAD)) 756 return -EINVAL; 757 758 /* copy eBPF program license from user space */ 759 if (strncpy_from_user(license, u64_to_user_ptr(attr->license), 760 sizeof(license) - 1) < 0) 761 return -EFAULT; 762 license[sizeof(license) - 1] = 0; 763 764 /* eBPF programs must be GPL compatible to use GPL-ed functions */ 765 is_gpl = license_is_gpl_compatible(license); 766 767 if (attr->insn_cnt >= BPF_MAXINSNS) 768 return -EINVAL; 769 770 if (type == BPF_PROG_TYPE_KPROBE && 771 attr->kern_version != LINUX_VERSION_CODE) 772 return -EINVAL; 773 774 if (type != BPF_PROG_TYPE_SOCKET_FILTER && !capable(CAP_SYS_ADMIN)) 775 return -EPERM; 776 777 /* plain bpf_prog allocation */ 778 prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER); 779 if (!prog) 780 return -ENOMEM; 781 782 err = bpf_prog_charge_memlock(prog); 783 if (err) 784 goto free_prog_nouncharge; 785 786 prog->len = attr->insn_cnt; 787 788 err = -EFAULT; 789 if (copy_from_user(prog->insns, u64_to_user_ptr(attr->insns), 790 prog->len * sizeof(struct bpf_insn)) != 0) 791 goto free_prog; 792 793 prog->orig_prog = NULL; 794 prog->jited = 0; 795 796 atomic_set(&prog->aux->refcnt, 1); 797 prog->gpl_compatible = is_gpl ? 1 : 0; 798 799 /* find program type: socket_filter vs tracing_filter */ 800 err = find_prog_type(type, prog); 801 if (err < 0) 802 goto free_prog; 803 804 /* run eBPF verifier */ 805 err = bpf_check(&prog, attr); 806 if (err < 0) 807 goto free_used_maps; 808 809 /* fixup BPF_CALL->imm field */ 810 fixup_bpf_calls(prog); 811 812 /* eBPF program is ready to be JITed */ 813 prog = bpf_prog_select_runtime(prog, &err); 814 if (err < 0) 815 goto free_used_maps; 816 817 err = bpf_prog_new_fd(prog); 818 if (err < 0) 819 /* failed to allocate fd */ 820 goto free_used_maps; 821 822 return err; 823 824 free_used_maps: 825 free_used_maps(prog->aux); 826 free_prog: 827 bpf_prog_uncharge_memlock(prog); 828 free_prog_nouncharge: 829 bpf_prog_free(prog); 830 return err; 831 } 832 833 #define BPF_OBJ_LAST_FIELD bpf_fd 834 835 static int bpf_obj_pin(const union bpf_attr *attr) 836 { 837 if (CHECK_ATTR(BPF_OBJ)) 838 return -EINVAL; 839 840 return bpf_obj_pin_user(attr->bpf_fd, u64_to_user_ptr(attr->pathname)); 841 } 842 843 static int bpf_obj_get(const union bpf_attr *attr) 844 { 845 if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0) 846 return -EINVAL; 847 848 return bpf_obj_get_user(u64_to_user_ptr(attr->pathname)); 849 } 850 851 #ifdef CONFIG_CGROUP_BPF 852 853 #define BPF_PROG_ATTACH_LAST_FIELD attach_type 854 855 static int bpf_prog_attach(const union bpf_attr *attr) 856 { 857 struct bpf_prog *prog; 858 struct cgroup *cgrp; 859 enum bpf_prog_type ptype; 860 861 if (!capable(CAP_NET_ADMIN)) 862 return -EPERM; 863 864 if (CHECK_ATTR(BPF_PROG_ATTACH)) 865 return -EINVAL; 866 867 switch (attr->attach_type) { 868 case BPF_CGROUP_INET_INGRESS: 869 case BPF_CGROUP_INET_EGRESS: 870 ptype = BPF_PROG_TYPE_CGROUP_SKB; 871 break; 872 case BPF_CGROUP_INET_SOCK_CREATE: 873 ptype = BPF_PROG_TYPE_CGROUP_SOCK; 874 break; 875 default: 876 return -EINVAL; 877 } 878 879 prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype); 880 if (IS_ERR(prog)) 881 return PTR_ERR(prog); 882 883 cgrp = cgroup_get_from_fd(attr->target_fd); 884 if (IS_ERR(cgrp)) { 885 bpf_prog_put(prog); 886 return PTR_ERR(cgrp); 887 } 888 889 cgroup_bpf_update(cgrp, prog, attr->attach_type); 890 cgroup_put(cgrp); 891 892 return 0; 893 } 894 895 #define BPF_PROG_DETACH_LAST_FIELD attach_type 896 897 static int bpf_prog_detach(const union bpf_attr *attr) 898 { 899 struct cgroup *cgrp; 900 901 if (!capable(CAP_NET_ADMIN)) 902 return -EPERM; 903 904 if (CHECK_ATTR(BPF_PROG_DETACH)) 905 return -EINVAL; 906 907 switch (attr->attach_type) { 908 case BPF_CGROUP_INET_INGRESS: 909 case BPF_CGROUP_INET_EGRESS: 910 case BPF_CGROUP_INET_SOCK_CREATE: 911 cgrp = cgroup_get_from_fd(attr->target_fd); 912 if (IS_ERR(cgrp)) 913 return PTR_ERR(cgrp); 914 915 cgroup_bpf_update(cgrp, NULL, attr->attach_type); 916 cgroup_put(cgrp); 917 break; 918 919 default: 920 return -EINVAL; 921 } 922 923 return 0; 924 } 925 #endif /* CONFIG_CGROUP_BPF */ 926 927 SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) 928 { 929 union bpf_attr attr = {}; 930 int err; 931 932 if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled) 933 return -EPERM; 934 935 if (!access_ok(VERIFY_READ, uattr, 1)) 936 return -EFAULT; 937 938 if (size > PAGE_SIZE) /* silly large */ 939 return -E2BIG; 940 941 /* If we're handed a bigger struct than we know of, 942 * ensure all the unknown bits are 0 - i.e. new 943 * user-space does not rely on any kernel feature 944 * extensions we dont know about yet. 945 */ 946 if (size > sizeof(attr)) { 947 unsigned char __user *addr; 948 unsigned char __user *end; 949 unsigned char val; 950 951 addr = (void __user *)uattr + sizeof(attr); 952 end = (void __user *)uattr + size; 953 954 for (; addr < end; addr++) { 955 err = get_user(val, addr); 956 if (err) 957 return err; 958 if (val) 959 return -E2BIG; 960 } 961 size = sizeof(attr); 962 } 963 964 /* copy attributes from user space, may be less than sizeof(bpf_attr) */ 965 if (copy_from_user(&attr, uattr, size) != 0) 966 return -EFAULT; 967 968 switch (cmd) { 969 case BPF_MAP_CREATE: 970 err = map_create(&attr); 971 break; 972 case BPF_MAP_LOOKUP_ELEM: 973 err = map_lookup_elem(&attr); 974 break; 975 case BPF_MAP_UPDATE_ELEM: 976 err = map_update_elem(&attr); 977 break; 978 case BPF_MAP_DELETE_ELEM: 979 err = map_delete_elem(&attr); 980 break; 981 case BPF_MAP_GET_NEXT_KEY: 982 err = map_get_next_key(&attr); 983 break; 984 case BPF_PROG_LOAD: 985 err = bpf_prog_load(&attr); 986 break; 987 case BPF_OBJ_PIN: 988 err = bpf_obj_pin(&attr); 989 break; 990 case BPF_OBJ_GET: 991 err = bpf_obj_get(&attr); 992 break; 993 994 #ifdef CONFIG_CGROUP_BPF 995 case BPF_PROG_ATTACH: 996 err = bpf_prog_attach(&attr); 997 break; 998 case BPF_PROG_DETACH: 999 err = bpf_prog_detach(&attr); 1000 break; 1001 #endif 1002 1003 default: 1004 err = -EINVAL; 1005 break; 1006 } 1007 1008 return err; 1009 } 1010