Alexei Starovoitov | 99c55f7 | 2014-09-26 00:16:57 -0700 | [diff] [blame] | 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> |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 16 | #include <linux/file.h> |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 17 | #include <linux/license.h> |
| 18 | #include <linux/filter.h> |
Alexei Starovoitov | 2541517 | 2015-03-25 12:49:20 -0700 | [diff] [blame] | 19 | #include <linux/version.h> |
Alexei Starovoitov | 99c55f7 | 2014-09-26 00:16:57 -0700 | [diff] [blame] | 20 | |
| 21 | static LIST_HEAD(bpf_map_types); |
| 22 | |
| 23 | static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) |
| 24 | { |
| 25 | struct bpf_map_type_list *tl; |
| 26 | struct bpf_map *map; |
| 27 | |
| 28 | list_for_each_entry(tl, &bpf_map_types, list_node) { |
| 29 | if (tl->type == attr->map_type) { |
| 30 | map = tl->ops->map_alloc(attr); |
| 31 | if (IS_ERR(map)) |
| 32 | return map; |
| 33 | map->ops = tl->ops; |
| 34 | map->map_type = attr->map_type; |
| 35 | return map; |
| 36 | } |
| 37 | } |
| 38 | return ERR_PTR(-EINVAL); |
| 39 | } |
| 40 | |
| 41 | /* boot time registration of different map implementations */ |
| 42 | void bpf_register_map_type(struct bpf_map_type_list *tl) |
| 43 | { |
| 44 | list_add(&tl->list_node, &bpf_map_types); |
| 45 | } |
| 46 | |
| 47 | /* called from workqueue */ |
| 48 | static void bpf_map_free_deferred(struct work_struct *work) |
| 49 | { |
| 50 | struct bpf_map *map = container_of(work, struct bpf_map, work); |
| 51 | |
| 52 | /* implementation dependent freeing */ |
| 53 | map->ops->map_free(map); |
| 54 | } |
| 55 | |
| 56 | /* decrement map refcnt and schedule it for freeing via workqueue |
| 57 | * (unrelying map implementation ops->map_free() might sleep) |
| 58 | */ |
| 59 | void bpf_map_put(struct bpf_map *map) |
| 60 | { |
| 61 | if (atomic_dec_and_test(&map->refcnt)) { |
| 62 | INIT_WORK(&map->work, bpf_map_free_deferred); |
| 63 | schedule_work(&map->work); |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | static int bpf_map_release(struct inode *inode, struct file *filp) |
| 68 | { |
| 69 | struct bpf_map *map = filp->private_data; |
| 70 | |
Alexei Starovoitov | 04fd61a | 2015-05-19 16:59:03 -0700 | [diff] [blame] | 71 | if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY) |
| 72 | /* prog_array stores refcnt-ed bpf_prog pointers |
| 73 | * release them all when user space closes prog_array_fd |
| 74 | */ |
| 75 | bpf_prog_array_map_clear(map); |
| 76 | |
Alexei Starovoitov | 99c55f7 | 2014-09-26 00:16:57 -0700 | [diff] [blame] | 77 | bpf_map_put(map); |
| 78 | return 0; |
| 79 | } |
| 80 | |
| 81 | static const struct file_operations bpf_map_fops = { |
| 82 | .release = bpf_map_release, |
| 83 | }; |
| 84 | |
| 85 | /* helper macro to check that unused fields 'union bpf_attr' are zero */ |
| 86 | #define CHECK_ATTR(CMD) \ |
| 87 | memchr_inv((void *) &attr->CMD##_LAST_FIELD + \ |
| 88 | sizeof(attr->CMD##_LAST_FIELD), 0, \ |
| 89 | sizeof(*attr) - \ |
| 90 | offsetof(union bpf_attr, CMD##_LAST_FIELD) - \ |
| 91 | sizeof(attr->CMD##_LAST_FIELD)) != NULL |
| 92 | |
| 93 | #define BPF_MAP_CREATE_LAST_FIELD max_entries |
| 94 | /* called via syscall */ |
| 95 | static int map_create(union bpf_attr *attr) |
| 96 | { |
| 97 | struct bpf_map *map; |
| 98 | int err; |
| 99 | |
| 100 | err = CHECK_ATTR(BPF_MAP_CREATE); |
| 101 | if (err) |
| 102 | return -EINVAL; |
| 103 | |
| 104 | /* find map type and init map: hashtable vs rbtree vs bloom vs ... */ |
| 105 | map = find_and_alloc_map(attr); |
| 106 | if (IS_ERR(map)) |
| 107 | return PTR_ERR(map); |
| 108 | |
| 109 | atomic_set(&map->refcnt, 1); |
| 110 | |
| 111 | err = anon_inode_getfd("bpf-map", &bpf_map_fops, map, O_RDWR | O_CLOEXEC); |
| 112 | |
| 113 | if (err < 0) |
| 114 | /* failed to allocate fd */ |
| 115 | goto free_map; |
| 116 | |
| 117 | return err; |
| 118 | |
| 119 | free_map: |
| 120 | map->ops->map_free(map); |
| 121 | return err; |
| 122 | } |
| 123 | |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 124 | /* if error is returned, fd is released. |
| 125 | * On success caller should complete fd access with matching fdput() |
| 126 | */ |
| 127 | struct bpf_map *bpf_map_get(struct fd f) |
| 128 | { |
| 129 | struct bpf_map *map; |
| 130 | |
| 131 | if (!f.file) |
| 132 | return ERR_PTR(-EBADF); |
| 133 | |
| 134 | if (f.file->f_op != &bpf_map_fops) { |
| 135 | fdput(f); |
| 136 | return ERR_PTR(-EINVAL); |
| 137 | } |
| 138 | |
| 139 | map = f.file->private_data; |
| 140 | |
| 141 | return map; |
| 142 | } |
| 143 | |
| 144 | /* helper to convert user pointers passed inside __aligned_u64 fields */ |
| 145 | static void __user *u64_to_ptr(__u64 val) |
| 146 | { |
| 147 | return (void __user *) (unsigned long) val; |
| 148 | } |
| 149 | |
| 150 | /* last field in 'union bpf_attr' used by this command */ |
| 151 | #define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value |
| 152 | |
| 153 | static int map_lookup_elem(union bpf_attr *attr) |
| 154 | { |
| 155 | void __user *ukey = u64_to_ptr(attr->key); |
| 156 | void __user *uvalue = u64_to_ptr(attr->value); |
| 157 | int ufd = attr->map_fd; |
| 158 | struct fd f = fdget(ufd); |
| 159 | struct bpf_map *map; |
Alexei Starovoitov | 8ebe667 | 2015-01-22 17:11:08 -0800 | [diff] [blame] | 160 | void *key, *value, *ptr; |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 161 | int err; |
| 162 | |
| 163 | if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM)) |
| 164 | return -EINVAL; |
| 165 | |
| 166 | map = bpf_map_get(f); |
| 167 | if (IS_ERR(map)) |
| 168 | return PTR_ERR(map); |
| 169 | |
| 170 | err = -ENOMEM; |
| 171 | key = kmalloc(map->key_size, GFP_USER); |
| 172 | if (!key) |
| 173 | goto err_put; |
| 174 | |
| 175 | err = -EFAULT; |
| 176 | if (copy_from_user(key, ukey, map->key_size) != 0) |
| 177 | goto free_key; |
| 178 | |
Alexei Starovoitov | 8ebe667 | 2015-01-22 17:11:08 -0800 | [diff] [blame] | 179 | err = -ENOMEM; |
| 180 | value = kmalloc(map->value_size, GFP_USER); |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 181 | if (!value) |
Alexei Starovoitov | 8ebe667 | 2015-01-22 17:11:08 -0800 | [diff] [blame] | 182 | goto free_key; |
| 183 | |
| 184 | rcu_read_lock(); |
| 185 | ptr = map->ops->map_lookup_elem(map, key); |
| 186 | if (ptr) |
| 187 | memcpy(value, ptr, map->value_size); |
| 188 | rcu_read_unlock(); |
| 189 | |
| 190 | err = -ENOENT; |
| 191 | if (!ptr) |
| 192 | goto free_value; |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 193 | |
| 194 | err = -EFAULT; |
| 195 | if (copy_to_user(uvalue, value, map->value_size) != 0) |
Alexei Starovoitov | 8ebe667 | 2015-01-22 17:11:08 -0800 | [diff] [blame] | 196 | goto free_value; |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 197 | |
| 198 | err = 0; |
| 199 | |
Alexei Starovoitov | 8ebe667 | 2015-01-22 17:11:08 -0800 | [diff] [blame] | 200 | free_value: |
| 201 | kfree(value); |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 202 | free_key: |
| 203 | kfree(key); |
| 204 | err_put: |
| 205 | fdput(f); |
| 206 | return err; |
| 207 | } |
| 208 | |
Alexei Starovoitov | 3274f52 | 2014-11-13 17:36:44 -0800 | [diff] [blame] | 209 | #define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 210 | |
| 211 | static int map_update_elem(union bpf_attr *attr) |
| 212 | { |
| 213 | void __user *ukey = u64_to_ptr(attr->key); |
| 214 | void __user *uvalue = u64_to_ptr(attr->value); |
| 215 | int ufd = attr->map_fd; |
| 216 | struct fd f = fdget(ufd); |
| 217 | struct bpf_map *map; |
| 218 | void *key, *value; |
| 219 | int err; |
| 220 | |
| 221 | if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM)) |
| 222 | return -EINVAL; |
| 223 | |
| 224 | map = bpf_map_get(f); |
| 225 | if (IS_ERR(map)) |
| 226 | return PTR_ERR(map); |
| 227 | |
| 228 | err = -ENOMEM; |
| 229 | key = kmalloc(map->key_size, GFP_USER); |
| 230 | if (!key) |
| 231 | goto err_put; |
| 232 | |
| 233 | err = -EFAULT; |
| 234 | if (copy_from_user(key, ukey, map->key_size) != 0) |
| 235 | goto free_key; |
| 236 | |
| 237 | err = -ENOMEM; |
| 238 | value = kmalloc(map->value_size, GFP_USER); |
| 239 | if (!value) |
| 240 | goto free_key; |
| 241 | |
| 242 | err = -EFAULT; |
| 243 | if (copy_from_user(value, uvalue, map->value_size) != 0) |
| 244 | goto free_value; |
| 245 | |
| 246 | /* eBPF program that use maps are running under rcu_read_lock(), |
| 247 | * therefore all map accessors rely on this fact, so do the same here |
| 248 | */ |
| 249 | rcu_read_lock(); |
Alexei Starovoitov | 3274f52 | 2014-11-13 17:36:44 -0800 | [diff] [blame] | 250 | err = map->ops->map_update_elem(map, key, value, attr->flags); |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 251 | rcu_read_unlock(); |
| 252 | |
| 253 | free_value: |
| 254 | kfree(value); |
| 255 | free_key: |
| 256 | kfree(key); |
| 257 | err_put: |
| 258 | fdput(f); |
| 259 | return err; |
| 260 | } |
| 261 | |
| 262 | #define BPF_MAP_DELETE_ELEM_LAST_FIELD key |
| 263 | |
| 264 | static int map_delete_elem(union bpf_attr *attr) |
| 265 | { |
| 266 | void __user *ukey = u64_to_ptr(attr->key); |
| 267 | int ufd = attr->map_fd; |
| 268 | struct fd f = fdget(ufd); |
| 269 | struct bpf_map *map; |
| 270 | void *key; |
| 271 | int err; |
| 272 | |
| 273 | if (CHECK_ATTR(BPF_MAP_DELETE_ELEM)) |
| 274 | return -EINVAL; |
| 275 | |
| 276 | map = bpf_map_get(f); |
| 277 | if (IS_ERR(map)) |
| 278 | return PTR_ERR(map); |
| 279 | |
| 280 | err = -ENOMEM; |
| 281 | key = kmalloc(map->key_size, GFP_USER); |
| 282 | if (!key) |
| 283 | goto err_put; |
| 284 | |
| 285 | err = -EFAULT; |
| 286 | if (copy_from_user(key, ukey, map->key_size) != 0) |
| 287 | goto free_key; |
| 288 | |
| 289 | rcu_read_lock(); |
| 290 | err = map->ops->map_delete_elem(map, key); |
| 291 | rcu_read_unlock(); |
| 292 | |
| 293 | free_key: |
| 294 | kfree(key); |
| 295 | err_put: |
| 296 | fdput(f); |
| 297 | return err; |
| 298 | } |
| 299 | |
| 300 | /* last field in 'union bpf_attr' used by this command */ |
| 301 | #define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key |
| 302 | |
| 303 | static int map_get_next_key(union bpf_attr *attr) |
| 304 | { |
| 305 | void __user *ukey = u64_to_ptr(attr->key); |
| 306 | void __user *unext_key = u64_to_ptr(attr->next_key); |
| 307 | int ufd = attr->map_fd; |
| 308 | struct fd f = fdget(ufd); |
| 309 | struct bpf_map *map; |
| 310 | void *key, *next_key; |
| 311 | int err; |
| 312 | |
| 313 | if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY)) |
| 314 | return -EINVAL; |
| 315 | |
| 316 | map = bpf_map_get(f); |
| 317 | if (IS_ERR(map)) |
| 318 | return PTR_ERR(map); |
| 319 | |
| 320 | err = -ENOMEM; |
| 321 | key = kmalloc(map->key_size, GFP_USER); |
| 322 | if (!key) |
| 323 | goto err_put; |
| 324 | |
| 325 | err = -EFAULT; |
| 326 | if (copy_from_user(key, ukey, map->key_size) != 0) |
| 327 | goto free_key; |
| 328 | |
| 329 | err = -ENOMEM; |
| 330 | next_key = kmalloc(map->key_size, GFP_USER); |
| 331 | if (!next_key) |
| 332 | goto free_key; |
| 333 | |
| 334 | rcu_read_lock(); |
| 335 | err = map->ops->map_get_next_key(map, key, next_key); |
| 336 | rcu_read_unlock(); |
| 337 | if (err) |
| 338 | goto free_next_key; |
| 339 | |
| 340 | err = -EFAULT; |
| 341 | if (copy_to_user(unext_key, next_key, map->key_size) != 0) |
| 342 | goto free_next_key; |
| 343 | |
| 344 | err = 0; |
| 345 | |
| 346 | free_next_key: |
| 347 | kfree(next_key); |
| 348 | free_key: |
| 349 | kfree(key); |
| 350 | err_put: |
| 351 | fdput(f); |
| 352 | return err; |
| 353 | } |
| 354 | |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 355 | static LIST_HEAD(bpf_prog_types); |
| 356 | |
| 357 | static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog) |
| 358 | { |
| 359 | struct bpf_prog_type_list *tl; |
| 360 | |
| 361 | list_for_each_entry(tl, &bpf_prog_types, list_node) { |
| 362 | if (tl->type == type) { |
| 363 | prog->aux->ops = tl->ops; |
Daniel Borkmann | 24701ec | 2015-03-01 12:31:47 +0100 | [diff] [blame] | 364 | prog->type = type; |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 365 | return 0; |
| 366 | } |
| 367 | } |
Daniel Borkmann | 24701ec | 2015-03-01 12:31:47 +0100 | [diff] [blame] | 368 | |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 369 | return -EINVAL; |
| 370 | } |
| 371 | |
| 372 | void bpf_register_prog_type(struct bpf_prog_type_list *tl) |
| 373 | { |
| 374 | list_add(&tl->list_node, &bpf_prog_types); |
| 375 | } |
| 376 | |
Alexei Starovoitov | 0a542a8 | 2014-09-26 00:17:01 -0700 | [diff] [blame] | 377 | /* fixup insn->imm field of bpf_call instructions: |
| 378 | * if (insn->imm == BPF_FUNC_map_lookup_elem) |
| 379 | * insn->imm = bpf_map_lookup_elem - __bpf_call_base; |
| 380 | * else if (insn->imm == BPF_FUNC_map_update_elem) |
| 381 | * insn->imm = bpf_map_update_elem - __bpf_call_base; |
| 382 | * else ... |
| 383 | * |
| 384 | * this function is called after eBPF program passed verification |
| 385 | */ |
| 386 | static void fixup_bpf_calls(struct bpf_prog *prog) |
| 387 | { |
| 388 | const struct bpf_func_proto *fn; |
| 389 | int i; |
| 390 | |
| 391 | for (i = 0; i < prog->len; i++) { |
| 392 | struct bpf_insn *insn = &prog->insnsi[i]; |
| 393 | |
| 394 | if (insn->code == (BPF_JMP | BPF_CALL)) { |
| 395 | /* we reach here when program has bpf_call instructions |
| 396 | * and it passed bpf_check(), means that |
| 397 | * ops->get_func_proto must have been supplied, check it |
| 398 | */ |
| 399 | BUG_ON(!prog->aux->ops->get_func_proto); |
| 400 | |
Alexei Starovoitov | 04fd61a | 2015-05-19 16:59:03 -0700 | [diff] [blame] | 401 | if (insn->imm == BPF_FUNC_tail_call) { |
| 402 | /* mark bpf_tail_call as different opcode |
| 403 | * to avoid conditional branch in |
| 404 | * interpeter for every normal call |
| 405 | * and to prevent accidental JITing by |
| 406 | * JIT compiler that doesn't support |
| 407 | * bpf_tail_call yet |
| 408 | */ |
| 409 | insn->imm = 0; |
| 410 | insn->code |= BPF_X; |
| 411 | continue; |
| 412 | } |
| 413 | |
Alexei Starovoitov | 0a542a8 | 2014-09-26 00:17:01 -0700 | [diff] [blame] | 414 | fn = prog->aux->ops->get_func_proto(insn->imm); |
| 415 | /* all functions that have prototype and verifier allowed |
| 416 | * programs to call them, must be real in-kernel functions |
| 417 | */ |
| 418 | BUG_ON(!fn->func); |
| 419 | insn->imm = fn->func - __bpf_call_base; |
| 420 | } |
| 421 | } |
| 422 | } |
| 423 | |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 424 | /* drop refcnt on maps used by eBPF program and free auxilary data */ |
| 425 | static void free_used_maps(struct bpf_prog_aux *aux) |
| 426 | { |
| 427 | int i; |
| 428 | |
| 429 | for (i = 0; i < aux->used_map_cnt; i++) |
| 430 | bpf_map_put(aux->used_maps[i]); |
| 431 | |
| 432 | kfree(aux->used_maps); |
| 433 | } |
| 434 | |
Alexei Starovoitov | abf2e7d | 2015-05-28 19:26:02 -0700 | [diff] [blame] | 435 | static void __prog_put_rcu(struct rcu_head *rcu) |
| 436 | { |
| 437 | struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu); |
| 438 | |
| 439 | free_used_maps(aux); |
| 440 | bpf_prog_free(aux->prog); |
| 441 | } |
| 442 | |
| 443 | /* version of bpf_prog_put() that is called after a grace period */ |
| 444 | void bpf_prog_put_rcu(struct bpf_prog *prog) |
| 445 | { |
| 446 | if (atomic_dec_and_test(&prog->aux->refcnt)) { |
| 447 | prog->aux->prog = prog; |
| 448 | call_rcu(&prog->aux->rcu, __prog_put_rcu); |
| 449 | } |
| 450 | } |
| 451 | |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 452 | void bpf_prog_put(struct bpf_prog *prog) |
| 453 | { |
| 454 | if (atomic_dec_and_test(&prog->aux->refcnt)) { |
| 455 | free_used_maps(prog->aux); |
| 456 | bpf_prog_free(prog); |
| 457 | } |
| 458 | } |
Daniel Borkmann | e2e9b65 | 2015-03-01 12:31:48 +0100 | [diff] [blame] | 459 | EXPORT_SYMBOL_GPL(bpf_prog_put); |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 460 | |
| 461 | static int bpf_prog_release(struct inode *inode, struct file *filp) |
| 462 | { |
| 463 | struct bpf_prog *prog = filp->private_data; |
| 464 | |
Alexei Starovoitov | abf2e7d | 2015-05-28 19:26:02 -0700 | [diff] [blame] | 465 | bpf_prog_put_rcu(prog); |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 466 | return 0; |
| 467 | } |
| 468 | |
| 469 | static const struct file_operations bpf_prog_fops = { |
| 470 | .release = bpf_prog_release, |
| 471 | }; |
| 472 | |
| 473 | static struct bpf_prog *get_prog(struct fd f) |
| 474 | { |
| 475 | struct bpf_prog *prog; |
| 476 | |
| 477 | if (!f.file) |
| 478 | return ERR_PTR(-EBADF); |
| 479 | |
| 480 | if (f.file->f_op != &bpf_prog_fops) { |
| 481 | fdput(f); |
| 482 | return ERR_PTR(-EINVAL); |
| 483 | } |
| 484 | |
| 485 | prog = f.file->private_data; |
| 486 | |
| 487 | return prog; |
| 488 | } |
| 489 | |
| 490 | /* called by sockets/tracing/seccomp before attaching program to an event |
| 491 | * pairs with bpf_prog_put() |
| 492 | */ |
| 493 | struct bpf_prog *bpf_prog_get(u32 ufd) |
| 494 | { |
| 495 | struct fd f = fdget(ufd); |
| 496 | struct bpf_prog *prog; |
| 497 | |
| 498 | prog = get_prog(f); |
| 499 | |
| 500 | if (IS_ERR(prog)) |
| 501 | return prog; |
| 502 | |
| 503 | atomic_inc(&prog->aux->refcnt); |
| 504 | fdput(f); |
| 505 | return prog; |
| 506 | } |
Daniel Borkmann | e2e9b65 | 2015-03-01 12:31:48 +0100 | [diff] [blame] | 507 | EXPORT_SYMBOL_GPL(bpf_prog_get); |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 508 | |
| 509 | /* last field in 'union bpf_attr' used by this command */ |
Alexei Starovoitov | 2541517 | 2015-03-25 12:49:20 -0700 | [diff] [blame] | 510 | #define BPF_PROG_LOAD_LAST_FIELD kern_version |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 511 | |
| 512 | static int bpf_prog_load(union bpf_attr *attr) |
| 513 | { |
| 514 | enum bpf_prog_type type = attr->prog_type; |
| 515 | struct bpf_prog *prog; |
| 516 | int err; |
| 517 | char license[128]; |
| 518 | bool is_gpl; |
| 519 | |
| 520 | if (CHECK_ATTR(BPF_PROG_LOAD)) |
| 521 | return -EINVAL; |
| 522 | |
| 523 | /* copy eBPF program license from user space */ |
| 524 | if (strncpy_from_user(license, u64_to_ptr(attr->license), |
| 525 | sizeof(license) - 1) < 0) |
| 526 | return -EFAULT; |
| 527 | license[sizeof(license) - 1] = 0; |
| 528 | |
| 529 | /* eBPF programs must be GPL compatible to use GPL-ed functions */ |
| 530 | is_gpl = license_is_gpl_compatible(license); |
| 531 | |
| 532 | if (attr->insn_cnt >= BPF_MAXINSNS) |
| 533 | return -EINVAL; |
| 534 | |
Alexei Starovoitov | 2541517 | 2015-03-25 12:49:20 -0700 | [diff] [blame] | 535 | if (type == BPF_PROG_TYPE_KPROBE && |
| 536 | attr->kern_version != LINUX_VERSION_CODE) |
| 537 | return -EINVAL; |
| 538 | |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 539 | /* plain bpf_prog allocation */ |
| 540 | prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER); |
| 541 | if (!prog) |
| 542 | return -ENOMEM; |
| 543 | |
| 544 | prog->len = attr->insn_cnt; |
| 545 | |
| 546 | err = -EFAULT; |
| 547 | if (copy_from_user(prog->insns, u64_to_ptr(attr->insns), |
| 548 | prog->len * sizeof(struct bpf_insn)) != 0) |
| 549 | goto free_prog; |
| 550 | |
| 551 | prog->orig_prog = NULL; |
| 552 | prog->jited = false; |
| 553 | |
| 554 | atomic_set(&prog->aux->refcnt, 1); |
Daniel Borkmann | 24701ec | 2015-03-01 12:31:47 +0100 | [diff] [blame] | 555 | prog->gpl_compatible = is_gpl; |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 556 | |
| 557 | /* find program type: socket_filter vs tracing_filter */ |
| 558 | err = find_prog_type(type, prog); |
| 559 | if (err < 0) |
| 560 | goto free_prog; |
| 561 | |
| 562 | /* run eBPF verifier */ |
Alexei Starovoitov | 9bac3d6 | 2015-03-13 11:57:42 -0700 | [diff] [blame] | 563 | err = bpf_check(&prog, attr); |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 564 | if (err < 0) |
| 565 | goto free_used_maps; |
| 566 | |
Alexei Starovoitov | 0a542a8 | 2014-09-26 00:17:01 -0700 | [diff] [blame] | 567 | /* fixup BPF_CALL->imm field */ |
| 568 | fixup_bpf_calls(prog); |
| 569 | |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 570 | /* eBPF program is ready to be JITed */ |
Alexei Starovoitov | 04fd61a | 2015-05-19 16:59:03 -0700 | [diff] [blame] | 571 | err = bpf_prog_select_runtime(prog); |
| 572 | if (err < 0) |
| 573 | goto free_used_maps; |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 574 | |
| 575 | err = anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog, O_RDWR | O_CLOEXEC); |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 576 | if (err < 0) |
| 577 | /* failed to allocate fd */ |
| 578 | goto free_used_maps; |
| 579 | |
| 580 | return err; |
| 581 | |
| 582 | free_used_maps: |
| 583 | free_used_maps(prog->aux); |
| 584 | free_prog: |
| 585 | bpf_prog_free(prog); |
| 586 | return err; |
| 587 | } |
| 588 | |
Alexei Starovoitov | 99c55f7 | 2014-09-26 00:16:57 -0700 | [diff] [blame] | 589 | SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) |
| 590 | { |
| 591 | union bpf_attr attr = {}; |
| 592 | int err; |
| 593 | |
| 594 | /* the syscall is limited to root temporarily. This restriction will be |
| 595 | * lifted when security audit is clean. Note that eBPF+tracing must have |
| 596 | * this restriction, since it may pass kernel data to user space |
| 597 | */ |
| 598 | if (!capable(CAP_SYS_ADMIN)) |
| 599 | return -EPERM; |
| 600 | |
| 601 | if (!access_ok(VERIFY_READ, uattr, 1)) |
| 602 | return -EFAULT; |
| 603 | |
| 604 | if (size > PAGE_SIZE) /* silly large */ |
| 605 | return -E2BIG; |
| 606 | |
| 607 | /* If we're handed a bigger struct than we know of, |
| 608 | * ensure all the unknown bits are 0 - i.e. new |
| 609 | * user-space does not rely on any kernel feature |
| 610 | * extensions we dont know about yet. |
| 611 | */ |
| 612 | if (size > sizeof(attr)) { |
| 613 | unsigned char __user *addr; |
| 614 | unsigned char __user *end; |
| 615 | unsigned char val; |
| 616 | |
| 617 | addr = (void __user *)uattr + sizeof(attr); |
| 618 | end = (void __user *)uattr + size; |
| 619 | |
| 620 | for (; addr < end; addr++) { |
| 621 | err = get_user(val, addr); |
| 622 | if (err) |
| 623 | return err; |
| 624 | if (val) |
| 625 | return -E2BIG; |
| 626 | } |
| 627 | size = sizeof(attr); |
| 628 | } |
| 629 | |
| 630 | /* copy attributes from user space, may be less than sizeof(bpf_attr) */ |
| 631 | if (copy_from_user(&attr, uattr, size) != 0) |
| 632 | return -EFAULT; |
| 633 | |
| 634 | switch (cmd) { |
| 635 | case BPF_MAP_CREATE: |
| 636 | err = map_create(&attr); |
| 637 | break; |
Alexei Starovoitov | db20fd2 | 2014-09-26 00:16:59 -0700 | [diff] [blame] | 638 | case BPF_MAP_LOOKUP_ELEM: |
| 639 | err = map_lookup_elem(&attr); |
| 640 | break; |
| 641 | case BPF_MAP_UPDATE_ELEM: |
| 642 | err = map_update_elem(&attr); |
| 643 | break; |
| 644 | case BPF_MAP_DELETE_ELEM: |
| 645 | err = map_delete_elem(&attr); |
| 646 | break; |
| 647 | case BPF_MAP_GET_NEXT_KEY: |
| 648 | err = map_get_next_key(&attr); |
| 649 | break; |
Alexei Starovoitov | 09756af | 2014-09-26 00:17:00 -0700 | [diff] [blame] | 650 | case BPF_PROG_LOAD: |
| 651 | err = bpf_prog_load(&attr); |
| 652 | break; |
Alexei Starovoitov | 99c55f7 | 2014-09-26 00:16:57 -0700 | [diff] [blame] | 653 | default: |
| 654 | err = -EINVAL; |
| 655 | break; |
| 656 | } |
| 657 | |
| 658 | return err; |
| 659 | } |