1 /* 2 * Copyright (C) 2017-2018 Netronome Systems, Inc. 3 * 4 * This software is licensed under the GNU General License Version 2, 5 * June 1991 as shown in the file COPYING in the top-level directory of this 6 * source tree. 7 * 8 * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" 9 * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, 10 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 11 * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE 12 * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME 13 * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 14 */ 15 16 #include <linux/bpf.h> 17 #include <linux/bpf_verifier.h> 18 #include <linux/bug.h> 19 #include <linux/kdev_t.h> 20 #include <linux/list.h> 21 #include <linux/lockdep.h> 22 #include <linux/netdevice.h> 23 #include <linux/printk.h> 24 #include <linux/proc_ns.h> 25 #include <linux/rhashtable.h> 26 #include <linux/rtnetlink.h> 27 #include <linux/rwsem.h> 28 29 /* Protects offdevs, members of bpf_offload_netdev and offload members 30 * of all progs. 31 * RTNL lock cannot be taken when holding this lock. 32 */ 33 static DECLARE_RWSEM(bpf_devs_lock); 34 35 struct bpf_offload_dev { 36 struct list_head netdevs; 37 }; 38 39 struct bpf_offload_netdev { 40 struct rhash_head l; 41 struct net_device *netdev; 42 struct bpf_offload_dev *offdev; 43 struct list_head progs; 44 struct list_head maps; 45 struct list_head offdev_netdevs; 46 }; 47 48 static const struct rhashtable_params offdevs_params = { 49 .nelem_hint = 4, 50 .key_len = sizeof(struct net_device *), 51 .key_offset = offsetof(struct bpf_offload_netdev, netdev), 52 .head_offset = offsetof(struct bpf_offload_netdev, l), 53 .automatic_shrinking = true, 54 }; 55 56 static struct rhashtable offdevs; 57 static bool offdevs_inited; 58 59 static int bpf_dev_offload_check(struct net_device *netdev) 60 { 61 if (!netdev) 62 return -EINVAL; 63 if (!netdev->netdev_ops->ndo_bpf) 64 return -EOPNOTSUPP; 65 return 0; 66 } 67 68 static struct bpf_offload_netdev * 69 bpf_offload_find_netdev(struct net_device *netdev) 70 { 71 lockdep_assert_held(&bpf_devs_lock); 72 73 if (!offdevs_inited) 74 return NULL; 75 return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params); 76 } 77 78 int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr) 79 { 80 struct bpf_offload_netdev *ondev; 81 struct bpf_prog_offload *offload; 82 int err; 83 84 if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS && 85 attr->prog_type != BPF_PROG_TYPE_XDP) 86 return -EINVAL; 87 88 if (attr->prog_flags) 89 return -EINVAL; 90 91 offload = kzalloc(sizeof(*offload), GFP_USER); 92 if (!offload) 93 return -ENOMEM; 94 95 offload->prog = prog; 96 97 offload->netdev = dev_get_by_index(current->nsproxy->net_ns, 98 attr->prog_ifindex); 99 err = bpf_dev_offload_check(offload->netdev); 100 if (err) 101 goto err_maybe_put; 102 103 down_write(&bpf_devs_lock); 104 ondev = bpf_offload_find_netdev(offload->netdev); 105 if (!ondev) { 106 err = -EINVAL; 107 goto err_unlock; 108 } 109 prog->aux->offload = offload; 110 list_add_tail(&offload->offloads, &ondev->progs); 111 dev_put(offload->netdev); 112 up_write(&bpf_devs_lock); 113 114 return 0; 115 err_unlock: 116 up_write(&bpf_devs_lock); 117 err_maybe_put: 118 if (offload->netdev) 119 dev_put(offload->netdev); 120 kfree(offload); 121 return err; 122 } 123 124 static int __bpf_offload_ndo(struct bpf_prog *prog, enum bpf_netdev_command cmd, 125 struct netdev_bpf *data) 126 { 127 struct bpf_prog_offload *offload = prog->aux->offload; 128 struct net_device *netdev; 129 130 ASSERT_RTNL(); 131 132 if (!offload) 133 return -ENODEV; 134 netdev = offload->netdev; 135 136 data->command = cmd; 137 138 return netdev->netdev_ops->ndo_bpf(netdev, data); 139 } 140 141 int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env) 142 { 143 struct netdev_bpf data = {}; 144 int err; 145 146 data.verifier.prog = env->prog; 147 148 rtnl_lock(); 149 err = __bpf_offload_ndo(env->prog, BPF_OFFLOAD_VERIFIER_PREP, &data); 150 if (err) 151 goto exit_unlock; 152 153 env->prog->aux->offload->dev_ops = data.verifier.ops; 154 env->prog->aux->offload->dev_state = true; 155 exit_unlock: 156 rtnl_unlock(); 157 return err; 158 } 159 160 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env, 161 int insn_idx, int prev_insn_idx) 162 { 163 struct bpf_prog_offload *offload; 164 int ret = -ENODEV; 165 166 down_read(&bpf_devs_lock); 167 offload = env->prog->aux->offload; 168 if (offload) 169 ret = offload->dev_ops->insn_hook(env, insn_idx, prev_insn_idx); 170 up_read(&bpf_devs_lock); 171 172 return ret; 173 } 174 175 static void __bpf_prog_offload_destroy(struct bpf_prog *prog) 176 { 177 struct bpf_prog_offload *offload = prog->aux->offload; 178 struct netdev_bpf data = {}; 179 180 data.offload.prog = prog; 181 182 if (offload->dev_state) 183 WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data)); 184 185 /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */ 186 bpf_prog_free_id(prog, true); 187 188 list_del_init(&offload->offloads); 189 kfree(offload); 190 prog->aux->offload = NULL; 191 } 192 193 void bpf_prog_offload_destroy(struct bpf_prog *prog) 194 { 195 rtnl_lock(); 196 down_write(&bpf_devs_lock); 197 if (prog->aux->offload) 198 __bpf_prog_offload_destroy(prog); 199 up_write(&bpf_devs_lock); 200 rtnl_unlock(); 201 } 202 203 static int bpf_prog_offload_translate(struct bpf_prog *prog) 204 { 205 struct netdev_bpf data = {}; 206 int ret; 207 208 data.offload.prog = prog; 209 210 rtnl_lock(); 211 ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data); 212 rtnl_unlock(); 213 214 return ret; 215 } 216 217 static unsigned int bpf_prog_warn_on_exec(const void *ctx, 218 const struct bpf_insn *insn) 219 { 220 WARN(1, "attempt to execute device eBPF program on the host!"); 221 return 0; 222 } 223 224 int bpf_prog_offload_compile(struct bpf_prog *prog) 225 { 226 prog->bpf_func = bpf_prog_warn_on_exec; 227 228 return bpf_prog_offload_translate(prog); 229 } 230 231 struct ns_get_path_bpf_prog_args { 232 struct bpf_prog *prog; 233 struct bpf_prog_info *info; 234 }; 235 236 static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data) 237 { 238 struct ns_get_path_bpf_prog_args *args = private_data; 239 struct bpf_prog_aux *aux = args->prog->aux; 240 struct ns_common *ns; 241 struct net *net; 242 243 rtnl_lock(); 244 down_read(&bpf_devs_lock); 245 246 if (aux->offload) { 247 args->info->ifindex = aux->offload->netdev->ifindex; 248 net = dev_net(aux->offload->netdev); 249 get_net(net); 250 ns = &net->ns; 251 } else { 252 args->info->ifindex = 0; 253 ns = NULL; 254 } 255 256 up_read(&bpf_devs_lock); 257 rtnl_unlock(); 258 259 return ns; 260 } 261 262 int bpf_prog_offload_info_fill(struct bpf_prog_info *info, 263 struct bpf_prog *prog) 264 { 265 struct ns_get_path_bpf_prog_args args = { 266 .prog = prog, 267 .info = info, 268 }; 269 struct bpf_prog_aux *aux = prog->aux; 270 struct inode *ns_inode; 271 struct path ns_path; 272 char __user *uinsns; 273 void *res; 274 u32 ulen; 275 276 res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args); 277 if (IS_ERR(res)) { 278 if (!info->ifindex) 279 return -ENODEV; 280 return PTR_ERR(res); 281 } 282 283 down_read(&bpf_devs_lock); 284 285 if (!aux->offload) { 286 up_read(&bpf_devs_lock); 287 return -ENODEV; 288 } 289 290 ulen = info->jited_prog_len; 291 info->jited_prog_len = aux->offload->jited_len; 292 if (info->jited_prog_len & ulen) { 293 uinsns = u64_to_user_ptr(info->jited_prog_insns); 294 ulen = min_t(u32, info->jited_prog_len, ulen); 295 if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) { 296 up_read(&bpf_devs_lock); 297 return -EFAULT; 298 } 299 } 300 301 up_read(&bpf_devs_lock); 302 303 ns_inode = ns_path.dentry->d_inode; 304 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); 305 info->netns_ino = ns_inode->i_ino; 306 path_put(&ns_path); 307 308 return 0; 309 } 310 311 const struct bpf_prog_ops bpf_offload_prog_ops = { 312 }; 313 314 static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap, 315 enum bpf_netdev_command cmd) 316 { 317 struct netdev_bpf data = {}; 318 struct net_device *netdev; 319 320 ASSERT_RTNL(); 321 322 data.command = cmd; 323 data.offmap = offmap; 324 /* Caller must make sure netdev is valid */ 325 netdev = offmap->netdev; 326 327 return netdev->netdev_ops->ndo_bpf(netdev, &data); 328 } 329 330 struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr) 331 { 332 struct net *net = current->nsproxy->net_ns; 333 struct bpf_offload_netdev *ondev; 334 struct bpf_offloaded_map *offmap; 335 int err; 336 337 if (!capable(CAP_SYS_ADMIN)) 338 return ERR_PTR(-EPERM); 339 if (attr->map_type != BPF_MAP_TYPE_ARRAY && 340 attr->map_type != BPF_MAP_TYPE_HASH) 341 return ERR_PTR(-EINVAL); 342 343 offmap = kzalloc(sizeof(*offmap), GFP_USER); 344 if (!offmap) 345 return ERR_PTR(-ENOMEM); 346 347 bpf_map_init_from_attr(&offmap->map, attr); 348 349 rtnl_lock(); 350 down_write(&bpf_devs_lock); 351 offmap->netdev = __dev_get_by_index(net, attr->map_ifindex); 352 err = bpf_dev_offload_check(offmap->netdev); 353 if (err) 354 goto err_unlock; 355 356 ondev = bpf_offload_find_netdev(offmap->netdev); 357 if (!ondev) { 358 err = -EINVAL; 359 goto err_unlock; 360 } 361 362 err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC); 363 if (err) 364 goto err_unlock; 365 366 list_add_tail(&offmap->offloads, &ondev->maps); 367 up_write(&bpf_devs_lock); 368 rtnl_unlock(); 369 370 return &offmap->map; 371 372 err_unlock: 373 up_write(&bpf_devs_lock); 374 rtnl_unlock(); 375 kfree(offmap); 376 return ERR_PTR(err); 377 } 378 379 static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap) 380 { 381 WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE)); 382 /* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */ 383 bpf_map_free_id(&offmap->map, true); 384 list_del_init(&offmap->offloads); 385 offmap->netdev = NULL; 386 } 387 388 void bpf_map_offload_map_free(struct bpf_map *map) 389 { 390 struct bpf_offloaded_map *offmap = map_to_offmap(map); 391 392 rtnl_lock(); 393 down_write(&bpf_devs_lock); 394 if (offmap->netdev) 395 __bpf_map_offload_destroy(offmap); 396 up_write(&bpf_devs_lock); 397 rtnl_unlock(); 398 399 kfree(offmap); 400 } 401 402 int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value) 403 { 404 struct bpf_offloaded_map *offmap = map_to_offmap(map); 405 int ret = -ENODEV; 406 407 down_read(&bpf_devs_lock); 408 if (offmap->netdev) 409 ret = offmap->dev_ops->map_lookup_elem(offmap, key, value); 410 up_read(&bpf_devs_lock); 411 412 return ret; 413 } 414 415 int bpf_map_offload_update_elem(struct bpf_map *map, 416 void *key, void *value, u64 flags) 417 { 418 struct bpf_offloaded_map *offmap = map_to_offmap(map); 419 int ret = -ENODEV; 420 421 if (unlikely(flags > BPF_EXIST)) 422 return -EINVAL; 423 424 down_read(&bpf_devs_lock); 425 if (offmap->netdev) 426 ret = offmap->dev_ops->map_update_elem(offmap, key, value, 427 flags); 428 up_read(&bpf_devs_lock); 429 430 return ret; 431 } 432 433 int bpf_map_offload_delete_elem(struct bpf_map *map, void *key) 434 { 435 struct bpf_offloaded_map *offmap = map_to_offmap(map); 436 int ret = -ENODEV; 437 438 down_read(&bpf_devs_lock); 439 if (offmap->netdev) 440 ret = offmap->dev_ops->map_delete_elem(offmap, key); 441 up_read(&bpf_devs_lock); 442 443 return ret; 444 } 445 446 int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key) 447 { 448 struct bpf_offloaded_map *offmap = map_to_offmap(map); 449 int ret = -ENODEV; 450 451 down_read(&bpf_devs_lock); 452 if (offmap->netdev) 453 ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key); 454 up_read(&bpf_devs_lock); 455 456 return ret; 457 } 458 459 struct ns_get_path_bpf_map_args { 460 struct bpf_offloaded_map *offmap; 461 struct bpf_map_info *info; 462 }; 463 464 static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data) 465 { 466 struct ns_get_path_bpf_map_args *args = private_data; 467 struct ns_common *ns; 468 struct net *net; 469 470 rtnl_lock(); 471 down_read(&bpf_devs_lock); 472 473 if (args->offmap->netdev) { 474 args->info->ifindex = args->offmap->netdev->ifindex; 475 net = dev_net(args->offmap->netdev); 476 get_net(net); 477 ns = &net->ns; 478 } else { 479 args->info->ifindex = 0; 480 ns = NULL; 481 } 482 483 up_read(&bpf_devs_lock); 484 rtnl_unlock(); 485 486 return ns; 487 } 488 489 int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map) 490 { 491 struct ns_get_path_bpf_map_args args = { 492 .offmap = map_to_offmap(map), 493 .info = info, 494 }; 495 struct inode *ns_inode; 496 struct path ns_path; 497 void *res; 498 499 res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args); 500 if (IS_ERR(res)) { 501 if (!info->ifindex) 502 return -ENODEV; 503 return PTR_ERR(res); 504 } 505 506 ns_inode = ns_path.dentry->d_inode; 507 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); 508 info->netns_ino = ns_inode->i_ino; 509 path_put(&ns_path); 510 511 return 0; 512 } 513 514 static bool __bpf_offload_dev_match(struct bpf_prog *prog, 515 struct net_device *netdev) 516 { 517 struct bpf_offload_netdev *ondev1, *ondev2; 518 struct bpf_prog_offload *offload; 519 520 if (!bpf_prog_is_dev_bound(prog->aux)) 521 return false; 522 523 offload = prog->aux->offload; 524 if (!offload) 525 return false; 526 if (offload->netdev == netdev) 527 return true; 528 529 ondev1 = bpf_offload_find_netdev(offload->netdev); 530 ondev2 = bpf_offload_find_netdev(netdev); 531 532 return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev; 533 } 534 535 bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev) 536 { 537 bool ret; 538 539 down_read(&bpf_devs_lock); 540 ret = __bpf_offload_dev_match(prog, netdev); 541 up_read(&bpf_devs_lock); 542 543 return ret; 544 } 545 EXPORT_SYMBOL_GPL(bpf_offload_dev_match); 546 547 bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map) 548 { 549 struct bpf_offloaded_map *offmap; 550 bool ret; 551 552 if (!bpf_map_is_dev_bound(map)) 553 return bpf_map_offload_neutral(map); 554 offmap = map_to_offmap(map); 555 556 down_read(&bpf_devs_lock); 557 ret = __bpf_offload_dev_match(prog, offmap->netdev); 558 up_read(&bpf_devs_lock); 559 560 return ret; 561 } 562 563 int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev, 564 struct net_device *netdev) 565 { 566 struct bpf_offload_netdev *ondev; 567 int err; 568 569 ondev = kzalloc(sizeof(*ondev), GFP_KERNEL); 570 if (!ondev) 571 return -ENOMEM; 572 573 ondev->netdev = netdev; 574 ondev->offdev = offdev; 575 INIT_LIST_HEAD(&ondev->progs); 576 INIT_LIST_HEAD(&ondev->maps); 577 578 down_write(&bpf_devs_lock); 579 err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params); 580 if (err) { 581 netdev_warn(netdev, "failed to register for BPF offload\n"); 582 goto err_unlock_free; 583 } 584 585 list_add(&ondev->offdev_netdevs, &offdev->netdevs); 586 up_write(&bpf_devs_lock); 587 return 0; 588 589 err_unlock_free: 590 up_write(&bpf_devs_lock); 591 kfree(ondev); 592 return err; 593 } 594 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register); 595 596 void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev, 597 struct net_device *netdev) 598 { 599 struct bpf_offload_netdev *ondev, *altdev; 600 struct bpf_offloaded_map *offmap, *mtmp; 601 struct bpf_prog_offload *offload, *ptmp; 602 603 ASSERT_RTNL(); 604 605 down_write(&bpf_devs_lock); 606 ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params); 607 if (WARN_ON(!ondev)) 608 goto unlock; 609 610 WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params)); 611 list_del(&ondev->offdev_netdevs); 612 613 /* Try to move the objects to another netdev of the device */ 614 altdev = list_first_entry_or_null(&offdev->netdevs, 615 struct bpf_offload_netdev, 616 offdev_netdevs); 617 if (altdev) { 618 list_for_each_entry(offload, &ondev->progs, offloads) 619 offload->netdev = altdev->netdev; 620 list_splice_init(&ondev->progs, &altdev->progs); 621 622 list_for_each_entry(offmap, &ondev->maps, offloads) 623 offmap->netdev = altdev->netdev; 624 list_splice_init(&ondev->maps, &altdev->maps); 625 } else { 626 list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads) 627 __bpf_prog_offload_destroy(offload->prog); 628 list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads) 629 __bpf_map_offload_destroy(offmap); 630 } 631 632 WARN_ON(!list_empty(&ondev->progs)); 633 WARN_ON(!list_empty(&ondev->maps)); 634 kfree(ondev); 635 unlock: 636 up_write(&bpf_devs_lock); 637 } 638 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister); 639 640 struct bpf_offload_dev *bpf_offload_dev_create(void) 641 { 642 struct bpf_offload_dev *offdev; 643 int err; 644 645 down_write(&bpf_devs_lock); 646 if (!offdevs_inited) { 647 err = rhashtable_init(&offdevs, &offdevs_params); 648 if (err) 649 return ERR_PTR(err); 650 offdevs_inited = true; 651 } 652 up_write(&bpf_devs_lock); 653 654 offdev = kzalloc(sizeof(*offdev), GFP_KERNEL); 655 if (!offdev) 656 return ERR_PTR(-ENOMEM); 657 658 INIT_LIST_HEAD(&offdev->netdevs); 659 660 return offdev; 661 } 662 EXPORT_SYMBOL_GPL(bpf_offload_dev_create); 663 664 void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev) 665 { 666 WARN_ON(!list_empty(&offdev->netdevs)); 667 kfree(offdev); 668 } 669 EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy); 670