kernel/bpf/syscall.c

   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         struct bpf_map *map = filp->private_data;
 128
 129         if (map->ops->map_release)
 130                 map->ops->map_release(map, filp);
 131
 132         bpf_map_put_with_uref(map);
 133         return 0;
 134 }
 135
 136 #ifdef CONFIG_PROC_FS
 137 static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
 138 {
 139         const struct bpf_map *map = filp->private_data;
 140
 141         seq_printf(m,
 142                    "map_type:\t%u\n"
 143                    "key_size:\t%u\n"
 144                    "value_size:\t%u\n"
 145                    "max_entries:\t%u\n"
 146                    "map_flags:\t%#x\n",
 147                    map->map_type,
 148                    map->key_size,
 149                    map->value_size,
 150                    map->max_entries,
 151                    map->map_flags);
 152 }
 153 #endif
 154
 155 static const struct file_operations bpf_map_fops = {
 156 #ifdef CONFIG_PROC_FS
 157         .show_fdinfo    = bpf_map_show_fdinfo,
 158 #endif
 159         .release        = bpf_map_release,
 160 };
 161
 162 int bpf_map_new_fd(struct bpf_map *map)
 163 {
 164         return anon_inode_getfd("bpf-map", &bpf_map_fops, map,
 165                                 O_RDWR | O_CLOEXEC);
 166 }
 167
 168 /* helper macro to check that unused fields 'union bpf_attr' are zero */
 169 #define CHECK_ATTR(CMD) \
 170         memchr_inv((void *) &attr->CMD##_LAST_FIELD + \
 171                    sizeof(attr->CMD##_LAST_FIELD), 0, \
 172                    sizeof(*attr) - \
 173                    offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
 174                    sizeof(attr->CMD##_LAST_FIELD)) != NULL
 175
 176 #define BPF_MAP_CREATE_LAST_FIELD map_flags
 177 /* called via syscall */
 178 static int map_create(union bpf_attr *attr)
 179 {
 180         struct bpf_map *map;
 181         int err;
 182
 183         err = CHECK_ATTR(BPF_MAP_CREATE);
 184         if (err)
 185                 return -EINVAL;
 186
 187         /* find map type and init map: hashtable vs rbtree vs bloom vs ... */
 188         map = find_and_alloc_map(attr);
 189         if (IS_ERR(map))
 190                 return PTR_ERR(map);
 191
 192         atomic_set(&map->refcnt, 1);
 193         atomic_set(&map->usercnt, 1);
 194
 195         err = bpf_map_charge_memlock(map);
 196         if (err)
 197                 goto free_map_nouncharge;
 198
 199         err = bpf_map_new_fd(map);
 200         if (err < 0)
 201                 /* failed to allocate fd */
 202                 goto free_map;
 203
 204         return err;
 205
 206 free_map:
 207         bpf_map_uncharge_memlock(map);
 208 free_map_nouncharge:
 209         map->ops->map_free(map);
 210         return err;
 211 }
 212
 213 /* if error is returned, fd is released.
 214  * On success caller should complete fd access with matching fdput()
 215  */
 216 struct bpf_map *__bpf_map_get(struct fd f)
 217 {
 218         if (!f.file)
 219                 return ERR_PTR(-EBADF);
 220         if (f.file->f_op != &bpf_map_fops) {
 221                 fdput(f);
 222                 return ERR_PTR(-EINVAL);
 223         }
 224
 225         return f.file->private_data;
 226 }
 227
 228 /* prog's and map's refcnt limit */
 229 #define BPF_MAX_REFCNT 32768
 230
 231 struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref)
 232 {
 233         if (atomic_inc_return(&map->refcnt) > BPF_MAX_REFCNT) {
 234                 atomic_dec(&map->refcnt);
 235                 return ERR_PTR(-EBUSY);
 236         }
 237         if (uref)
 238                 atomic_inc(&map->usercnt);
 239         return map;
 240 }
 241
 242 struct bpf_map *bpf_map_get_with_uref(u32 ufd)
 243 {
 244         struct fd f = fdget(ufd);
 245         struct bpf_map *map;
 246
 247         map = __bpf_map_get(f);
 248         if (IS_ERR(map))
 249                 return map;
 250
 251         map = bpf_map_inc(map, true);
 252         fdput(f);
 253
 254         return map;
 255 }
 256
 257 /* helper to convert user pointers passed inside __aligned_u64 fields */
 258 static void __user *u64_to_ptr(__u64 val)
 259 {
 260         return (void __user *) (unsigned long) val;
 261 }
 262
 263 int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
 264 {
 265         return -ENOTSUPP;
 266 }
 267
 268 /* last field in 'union bpf_attr' used by this command */
 269 #define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value
 270
 271 static int map_lookup_elem(union bpf_attr *attr)
 272 {
 273         void __user *ukey = u64_to_ptr(attr->key);
 274         void __user *uvalue = u64_to_ptr(attr->value);
 275         int ufd = attr->map_fd;
 276         struct bpf_map *map;
 277         void *key, *value, *ptr;
 278         u32 value_size;
 279         struct fd f;
 280         int err;
 281
 282         if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM))
 283                 return -EINVAL;
 284
 285         f = fdget(ufd);
 286         map = __bpf_map_get(f);
 287         if (IS_ERR(map))
 288                 return PTR_ERR(map);
 289
 290         err = -ENOMEM;
 291         key = kmalloc(map->key_size, GFP_USER);
 292         if (!key)
 293                 goto err_put;
 294
 295         err = -EFAULT;
 296         if (copy_from_user(key, ukey, map->key_size) != 0)
 297                 goto free_key;
 298
 299         if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
 300             map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
 301                 value_size = round_up(map->value_size, 8) * num_possible_cpus();
 302         else
 303                 value_size = map->value_size;
 304
 305         err = -ENOMEM;
 306         value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
 307         if (!value)
 308                 goto free_key;
 309
 310         if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
 311                 err = bpf_percpu_hash_copy(map, key, value);
 312         } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
 313                 err = bpf_percpu_array_copy(map, key, value);
 314         } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
 315                 err = bpf_stackmap_copy(map, key, value);
 316         } else {
 317                 rcu_read_lock();
 318                 ptr = map->ops->map_lookup_elem(map, key);
 319                 if (ptr)
 320                         memcpy(value, ptr, value_size);
 321                 rcu_read_unlock();
 322                 err = ptr ? 0 : -ENOENT;
 323         }
 324
 325         if (err)
 326                 goto free_value;
 327
 328         err = -EFAULT;
 329         if (copy_to_user(uvalue, value, value_size) != 0)
 330                 goto free_value;
 331
 332         err = 0;
 333
 334 free_value:
 335         kfree(value);
 336 free_key:
 337         kfree(key);
 338 err_put:
 339         fdput(f);
 340         return err;
 341 }
 342
 343 #define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags
 344
 345 static int map_update_elem(union bpf_attr *attr)
 346 {
 347         void __user *ukey = u64_to_ptr(attr->key);
 348         void __user *uvalue = u64_to_ptr(attr->value);
 349         int ufd = attr->map_fd;
 350         struct bpf_map *map;
 351         void *key, *value;
 352         u32 value_size;
 353         struct fd f;
 354         int err;
 355
 356         if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM))
 357                 return -EINVAL;
 358
 359         f = fdget(ufd);
 360         map = __bpf_map_get(f);
 361         if (IS_ERR(map))
 362                 return PTR_ERR(map);
 363
 364         err = -ENOMEM;
 365         key = kmalloc(map->key_size, GFP_USER);
 366         if (!key)
 367                 goto err_put;
 368
 369         err = -EFAULT;
 370         if (copy_from_user(key, ukey, map->key_size) != 0)
 371                 goto free_key;
 372
 373         if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
 374             map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
 375                 value_size = round_up(map->value_size, 8) * num_possible_cpus();
 376         else
 377                 value_size = map->value_size;
 378
 379         err = -ENOMEM;
 380         value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
 381         if (!value)
 382                 goto free_key;
 383
 384         err = -EFAULT;
 385         if (copy_from_user(value, uvalue, value_size) != 0)
 386                 goto free_value;
 387
 388         /* must increment bpf_prog_active to avoid kprobe+bpf triggering from
 389          * inside bpf map update or delete otherwise deadlocks are possible
 390          */
 391         preempt_disable();
 392         __this_cpu_inc(bpf_prog_active);
 393         if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH) {
 394                 err = bpf_percpu_hash_update(map, key, value, attr->flags);
 395         } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
 396                 err = bpf_percpu_array_update(map, key, value, attr->flags);
 397         } else if (map->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY ||
 398                    map->map_type == BPF_MAP_TYPE_PROG_ARRAY ||
 399                    map->map_type == BPF_MAP_TYPE_CGROUP_ARRAY) {
 400                 rcu_read_lock();
 401                 err = bpf_fd_array_map_update_elem(map, f.file, key, value,
 402                                                    attr->flags);
 403                 rcu_read_unlock();
 404         } else {
 405                 rcu_read_lock();
 406                 err = map->ops->map_update_elem(map, key, value, attr->flags);
 407                 rcu_read_unlock();
 408         }
 409         __this_cpu_dec(bpf_prog_active);
 410         preempt_enable();
 411
 412 free_value:
 413         kfree(value);
 414 free_key:
 415         kfree(key);
 416 err_put:
 417         fdput(f);
 418         return err;
 419 }
 420
 421 #define BPF_MAP_DELETE_ELEM_LAST_FIELD key
 422
 423 static int map_delete_elem(union bpf_attr *attr)
 424 {
 425         void __user *ukey = u64_to_ptr(attr->key);
 426         int ufd = attr->map_fd;
 427         struct bpf_map *map;
 428         struct fd f;
 429         void *key;
 430         int err;
 431
 432         if (CHECK_ATTR(BPF_MAP_DELETE_ELEM))
 433                 return -EINVAL;
 434
 435         f = fdget(ufd);
 436         map = __bpf_map_get(f);
 437         if (IS_ERR(map))
 438                 return PTR_ERR(map);
 439
 440         err = -ENOMEM;
 441         key = kmalloc(map->key_size, GFP_USER);
 442         if (!key)
 443                 goto err_put;
 444
 445         err = -EFAULT;
 446         if (copy_from_user(key, ukey, map->key_size) != 0)
 447                 goto free_key;
 448
 449         preempt_disable();
 450         __this_cpu_inc(bpf_prog_active);
 451         rcu_read_lock();
 452         err = map->ops->map_delete_elem(map, key);
 453         rcu_read_unlock();
 454         __this_cpu_dec(bpf_prog_active);
 455         preempt_enable();
 456
 457 free_key:
 458         kfree(key);
 459 err_put:
 460         fdput(f);
 461         return err;
 462 }
 463
 464 /* last field in 'union bpf_attr' used by this command */
 465 #define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key
 466
 467 static int map_get_next_key(union bpf_attr *attr)
 468 {
 469         void __user *ukey = u64_to_ptr(attr->key);
 470         void __user *unext_key = u64_to_ptr(attr->next_key);
 471         int ufd = attr->map_fd;
 472         struct bpf_map *map;
 473         void *key, *next_key;
 474         struct fd f;
 475         int err;
 476
 477         if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY))
 478                 return -EINVAL;
 479
 480         f = fdget(ufd);
 481         map = __bpf_map_get(f);
 482         if (IS_ERR(map))
 483                 return PTR_ERR(map);
 484
 485         err = -ENOMEM;
 486         key = kmalloc(map->key_size, GFP_USER);
 487         if (!key)
 488                 goto err_put;
 489
 490         err = -EFAULT;
 491         if (copy_from_user(key, ukey, map->key_size) != 0)
 492                 goto free_key;
 493
 494         err = -ENOMEM;
 495         next_key = kmalloc(map->key_size, GFP_USER);
 496         if (!next_key)
 497                 goto free_key;
 498
 499         rcu_read_lock();
 500         err = map->ops->map_get_next_key(map, key, next_key);
 501         rcu_read_unlock();
 502         if (err)
 503                 goto free_next_key;
 504
 505         err = -EFAULT;
 506         if (copy_to_user(unext_key, next_key, map->key_size) != 0)
 507                 goto free_next_key;
 508
 509         err = 0;
 510
 511 free_next_key:
 512         kfree(next_key);
 513 free_key:
 514         kfree(key);
 515 err_put:
 516         fdput(f);
 517         return err;
 518 }
 519
 520 static LIST_HEAD(bpf_prog_types);
 521
 522 static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
 523 {
 524         struct bpf_prog_type_list *tl;
 525
 526         list_for_each_entry(tl, &bpf_prog_types, list_node) {
 527                 if (tl->type == type) {
 528                         prog->aux->ops = tl->ops;
 529                         prog->type = type;
 530                         return 0;
 531                 }
 532         }
 533
 534         return -EINVAL;
 535 }
 536
 537 void bpf_register_prog_type(struct bpf_prog_type_list *tl)
 538 {
 539         list_add(&tl->list_node, &bpf_prog_types);
 540 }
 541
 542 /* fixup insn->imm field of bpf_call instructions:
 543  * if (insn->imm == BPF_FUNC_map_lookup_elem)
 544  *      insn->imm = bpf_map_lookup_elem - __bpf_call_base;
 545  * else if (insn->imm == BPF_FUNC_map_update_elem)
 546  *      insn->imm = bpf_map_update_elem - __bpf_call_base;
 547  * else ...
 548  *
 549  * this function is called after eBPF program passed verification
 550  */
 551 static void fixup_bpf_calls(struct bpf_prog *prog)
 552 {
 553         const struct bpf_func_proto *fn;
 554         int i;
 555
 556         for (i = 0; i < prog->len; i++) {
 557                 struct bpf_insn *insn = &prog->insnsi[i];
 558
 559                 if (insn->code == (BPF_JMP | BPF_CALL)) {
 560                         /* we reach here when program has bpf_call instructions
 561                          * and it passed bpf_check(), means that
 562                          * ops->get_func_proto must have been supplied, check it
 563                          */
 564                         BUG_ON(!prog->aux->ops->get_func_proto);
 565
 566                         if (insn->imm == BPF_FUNC_get_route_realm)
 567                                 prog->dst_needed = 1;
 568                         if (insn->imm == BPF_FUNC_get_prandom_u32)
 569                                 bpf_user_rnd_init_once();
 570                         if (insn->imm == BPF_FUNC_tail_call) {
 571                                 /* mark bpf_tail_call as different opcode
 572                                  * to avoid conditional branch in
 573                                  * interpeter for every normal call
 574                                  * and to prevent accidental JITing by
 575                                  * JIT compiler that doesn't support
 576                                  * bpf_tail_call yet
 577                                  */
 578                                 insn->imm = 0;
 579                                 insn->code |= BPF_X;
 580                                 continue;
 581                         }
 582
 583                         fn = prog->aux->ops->get_func_proto(insn->imm);
 584                         /* all functions that have prototype and verifier allowed
 585                          * programs to call them, must be real in-kernel functions
 586                          */
 587                         BUG_ON(!fn->func);
 588                         insn->imm = fn->func - __bpf_call_base;
 589                 }
 590         }
 591 }
 592
 593 /* drop refcnt on maps used by eBPF program and free auxilary data */
 594 static void free_used_maps(struct bpf_prog_aux *aux)
 595 {
 596         int i;
 597
 598         for (i = 0; i < aux->used_map_cnt; i++)
 599                 bpf_map_put(aux->used_maps[i]);
 600
 601         kfree(aux->used_maps);
 602 }
 603
 604 static int bpf_prog_charge_memlock(struct bpf_prog *prog)
 605 {
 606         struct user_struct *user = get_current_user();
 607         unsigned long memlock_limit;
 608
 609         memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 610
 611         atomic_long_add(prog->pages, &user->locked_vm);
 612         if (atomic_long_read(&user->locked_vm) > memlock_limit) {
 613                 atomic_long_sub(prog->pages, &user->locked_vm);
 614                 free_uid(user);
 615                 return -EPERM;
 616         }
 617         prog->aux->user = user;
 618         return 0;
 619 }
 620
 621 static void bpf_prog_uncharge_memlock(struct bpf_prog *prog)
 622 {
 623         struct user_struct *user = prog->aux->user;
 624
 625         atomic_long_sub(prog->pages, &user->locked_vm);
 626         free_uid(user);
 627 }
 628
 629 static void __bpf_prog_put_rcu(struct rcu_head *rcu)
 630 {
 631         struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);
 632
 633         free_used_maps(aux);
 634         bpf_prog_uncharge_memlock(aux->prog);
 635         bpf_prog_free(aux->prog);
 636 }
 637
 638 void bpf_prog_put(struct bpf_prog *prog)
 639 {
 640         if (atomic_dec_and_test(&prog->aux->refcnt))
 641                 call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu);
 642 }
 643 EXPORT_SYMBOL_GPL(bpf_prog_put);
 644
 645 static int bpf_prog_release(struct inode *inode, struct file *filp)
 646 {
 647         struct bpf_prog *prog = filp->private_data;
 648
 649         bpf_prog_put(prog);
 650         return 0;
 651 }
 652
 653 static const struct file_operations bpf_prog_fops = {
 654         .release = bpf_prog_release,
 655 };
 656
 657 int bpf_prog_new_fd(struct bpf_prog *prog)
 658 {
 659         return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog,
 660                                 O_RDWR | O_CLOEXEC);
 661 }
 662
 663 static struct bpf_prog *____bpf_prog_get(struct fd f)
 664 {
 665         if (!f.file)
 666                 return ERR_PTR(-EBADF);
 667         if (f.file->f_op != &bpf_prog_fops) {
 668                 fdput(f);
 669                 return ERR_PTR(-EINVAL);
 670         }
 671
 672         return f.file->private_data;
 673 }
 674
 675 struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i)
 676 {
 677         if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) {
 678                 atomic_sub(i, &prog->aux->refcnt);
 679                 return ERR_PTR(-EBUSY);
 680         }
 681         return prog;
 682 }
 683 EXPORT_SYMBOL_GPL(bpf_prog_add);
 684
 685 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
 686 {
 687         return bpf_prog_add(prog, 1);
 688 }
 689
 690 static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type)
 691 {
 692         struct fd f = fdget(ufd);
 693         struct bpf_prog *prog;
 694
 695         prog = ____bpf_prog_get(f);
 696         if (IS_ERR(prog))
 697                 return prog;
 698         if (type && prog->type != *type) {
 699                 prog = ERR_PTR(-EINVAL);
 700                 goto out;
 701         }
 702
 703         prog = bpf_prog_inc(prog);
 704 out:
 705         fdput(f);
 706         return prog;
 707 }
 708
 709 struct bpf_prog *bpf_prog_get(u32 ufd)
 710 {
 711         return __bpf_prog_get(ufd, NULL);
 712 }
 713
 714 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type)
 715 {
 716         return __bpf_prog_get(ufd, &type);
 717 }
 718 EXPORT_SYMBOL_GPL(bpf_prog_get_type);
 719
 720 /* last field in 'union bpf_attr' used by this command */
 721 #define BPF_PROG_LOAD_LAST_FIELD kern_version
 722
 723 static int bpf_prog_load(union bpf_attr *attr)
 724 {
 725         enum bpf_prog_type type = attr->prog_type;
 726         struct bpf_prog *prog;
 727         int err;
 728         char license[128];
 729         bool is_gpl;
 730
 731         if (CHECK_ATTR(BPF_PROG_LOAD))
 732                 return -EINVAL;
 733
 734         /* copy eBPF program license from user space */
 735         if (strncpy_from_user(license, u64_to_ptr(attr->license),
 736                               sizeof(license) - 1) < 0)
 737                 return -EFAULT;
 738         license[sizeof(license) - 1] = 0;
 739
 740         /* eBPF programs must be GPL compatible to use GPL-ed functions */
 741         is_gpl = license_is_gpl_compatible(license);
 742
 743         if (attr->insn_cnt >= BPF_MAXINSNS)
 744                 return -EINVAL;
 745
 746         if (type == BPF_PROG_TYPE_KPROBE &&
 747             attr->kern_version != LINUX_VERSION_CODE)
 748                 return -EINVAL;
 749
 750         if (type != BPF_PROG_TYPE_SOCKET_FILTER && !capable(CAP_SYS_ADMIN))
 751                 return -EPERM;
 752
 753         /* plain bpf_prog allocation */
 754         prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
 755         if (!prog)
 756                 return -ENOMEM;
 757
 758         err = bpf_prog_charge_memlock(prog);
 759         if (err)
 760                 goto free_prog_nouncharge;
 761
 762         prog->len = attr->insn_cnt;
 763
 764         err = -EFAULT;
 765         if (copy_from_user(prog->insns, u64_to_ptr(attr->insns),
 766                            prog->len * sizeof(struct bpf_insn)) != 0)
 767                 goto free_prog;
 768
 769         prog->orig_prog = NULL;
 770         prog->jited = 0;
 771
 772         atomic_set(&prog->aux->refcnt, 1);
 773         prog->gpl_compatible = is_gpl ? 1 : 0;
 774
 775         /* find program type: socket_filter vs tracing_filter */
 776         err = find_prog_type(type, prog);
 777         if (err < 0)
 778                 goto free_prog;
 779
 780         /* run eBPF verifier */
 781         err = bpf_check(&prog, attr);
 782         if (err < 0)
 783                 goto free_used_maps;
 784
 785         /* fixup BPF_CALL->imm field */
 786         fixup_bpf_calls(prog);
 787
 788         /* eBPF program is ready to be JITed */
 789         prog = bpf_prog_select_runtime(prog, &err);
 790         if (err < 0)
 791                 goto free_used_maps;
 792
 793         err = bpf_prog_new_fd(prog);
 794         if (err < 0)
 795                 /* failed to allocate fd */
 796                 goto free_used_maps;
 797
 798         return err;
 799
 800 free_used_maps:
 801         free_used_maps(prog->aux);
 802 free_prog:
 803         bpf_prog_uncharge_memlock(prog);
 804 free_prog_nouncharge:
 805         bpf_prog_free(prog);
 806         return err;
 807 }
 808
 809 #define BPF_OBJ_LAST_FIELD bpf_fd
 810
 811 static int bpf_obj_pin(const union bpf_attr *attr)
 812 {
 813         if (CHECK_ATTR(BPF_OBJ))
 814                 return -EINVAL;
 815
 816         return bpf_obj_pin_user(attr->bpf_fd, u64_to_ptr(attr->pathname));
 817 }
 818
 819 static int bpf_obj_get(const union bpf_attr *attr)
 820 {
 821         if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0)
 822                 return -EINVAL;
 823
 824         return bpf_obj_get_user(u64_to_ptr(attr->pathname));
 825 }
 826
 827 SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
 828 {
 829         union bpf_attr attr = {};
 830         int err;
 831
 832         if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled)
 833                 return -EPERM;
 834
 835         if (!access_ok(VERIFY_READ, uattr, 1))
 836                 return -EFAULT;
 837
 838         if (size > PAGE_SIZE)   /* silly large */
 839                 return -E2BIG;
 840
 841         /* If we're handed a bigger struct than we know of,
 842          * ensure all the unknown bits are 0 - i.e. new
 843          * user-space does not rely on any kernel feature
 844          * extensions we dont know about yet.
 845          */
 846         if (size > sizeof(attr)) {
 847                 unsigned char __user *addr;
 848                 unsigned char __user *end;
 849                 unsigned char val;
 850
 851                 addr = (void __user *)uattr + sizeof(attr);
 852                 end  = (void __user *)uattr + size;
 853
 854                 for (; addr < end; addr++) {
 855                         err = get_user(val, addr);
 856                         if (err)
 857                                 return err;
 858                         if (val)
 859                                 return -E2BIG;
 860                 }
 861                 size = sizeof(attr);
 862         }
 863
 864         /* copy attributes from user space, may be less than sizeof(bpf_attr) */
 865         if (copy_from_user(&attr, uattr, size) != 0)
 866                 return -EFAULT;
 867
 868         switch (cmd) {
 869         case BPF_MAP_CREATE:
 870                 err = map_create(&attr);
 871                 break;
 872         case BPF_MAP_LOOKUP_ELEM:
 873                 err = map_lookup_elem(&attr);
 874                 break;
 875         case BPF_MAP_UPDATE_ELEM:
 876                 err = map_update_elem(&attr);
 877                 break;
 878         case BPF_MAP_DELETE_ELEM:
 879                 err = map_delete_elem(&attr);
 880                 break;
 881         case BPF_MAP_GET_NEXT_KEY:
 882                 err = map_get_next_key(&attr);
 883                 break;
 884         case BPF_PROG_LOAD:
 885                 err = bpf_prog_load(&attr);
 886                 break;
 887         case BPF_OBJ_PIN:
 888                 err = bpf_obj_pin(&attr);
 889                 break;
 890         case BPF_OBJ_GET:
 891                 err = bpf_obj_get(&attr);
 892                 break;
 893         default:
 894                 err = -EINVAL;
 895                 break;
 896         }
 897
 898         return err;
 899 }