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 int bpf_prog_offload_finalize(struct bpf_verifier_env *env) 176 { 177 struct bpf_prog_offload *offload; 178 int ret = -ENODEV; 179 180 down_read(&bpf_devs_lock); 181 offload = env->prog->aux->offload; 182 if (offload) { 183 if (offload->dev_ops->finalize) 184 ret = offload->dev_ops->finalize(env); 185 else 186 ret = 0; 187 } 188 up_read(&bpf_devs_lock); 189 190 return ret; 191 } 192 193 static void __bpf_prog_offload_destroy(struct bpf_prog *prog) 194 { 195 struct bpf_prog_offload *offload = prog->aux->offload; 196 struct netdev_bpf data = {}; 197 198 data.offload.prog = prog; 199 200 if (offload->dev_state) 201 WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data)); 202 203 /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */ 204 bpf_prog_free_id(prog, true); 205 206 list_del_init(&offload->offloads); 207 kfree(offload); 208 prog->aux->offload = NULL; 209 } 210 211 void bpf_prog_offload_destroy(struct bpf_prog *prog) 212 { 213 rtnl_lock(); 214 down_write(&bpf_devs_lock); 215 if (prog->aux->offload) 216 __bpf_prog_offload_destroy(prog); 217 up_write(&bpf_devs_lock); 218 rtnl_unlock(); 219 } 220 221 static int bpf_prog_offload_translate(struct bpf_prog *prog) 222 { 223 struct netdev_bpf data = {}; 224 int ret; 225 226 data.offload.prog = prog; 227 228 rtnl_lock(); 229 ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data); 230 rtnl_unlock(); 231 232 return ret; 233 } 234 235 static unsigned int bpf_prog_warn_on_exec(const void *ctx, 236 const struct bpf_insn *insn) 237 { 238 WARN(1, "attempt to execute device eBPF program on the host!"); 239 return 0; 240 } 241 242 int bpf_prog_offload_compile(struct bpf_prog *prog) 243 { 244 prog->bpf_func = bpf_prog_warn_on_exec; 245 246 return bpf_prog_offload_translate(prog); 247 } 248 249 struct ns_get_path_bpf_prog_args { 250 struct bpf_prog *prog; 251 struct bpf_prog_info *info; 252 }; 253 254 static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data) 255 { 256 struct ns_get_path_bpf_prog_args *args = private_data; 257 struct bpf_prog_aux *aux = args->prog->aux; 258 struct ns_common *ns; 259 struct net *net; 260 261 rtnl_lock(); 262 down_read(&bpf_devs_lock); 263 264 if (aux->offload) { 265 args->info->ifindex = aux->offload->netdev->ifindex; 266 net = dev_net(aux->offload->netdev); 267 get_net(net); 268 ns = &net->ns; 269 } else { 270 args->info->ifindex = 0; 271 ns = NULL; 272 } 273 274 up_read(&bpf_devs_lock); 275 rtnl_unlock(); 276 277 return ns; 278 } 279 280 int bpf_prog_offload_info_fill(struct bpf_prog_info *info, 281 struct bpf_prog *prog) 282 { 283 struct ns_get_path_bpf_prog_args args = { 284 .prog = prog, 285 .info = info, 286 }; 287 struct bpf_prog_aux *aux = prog->aux; 288 struct inode *ns_inode; 289 struct path ns_path; 290 char __user *uinsns; 291 void *res; 292 u32 ulen; 293 294 res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args); 295 if (IS_ERR(res)) { 296 if (!info->ifindex) 297 return -ENODEV; 298 return PTR_ERR(res); 299 } 300 301 down_read(&bpf_devs_lock); 302 303 if (!aux->offload) { 304 up_read(&bpf_devs_lock); 305 return -ENODEV; 306 } 307 308 ulen = info->jited_prog_len; 309 info->jited_prog_len = aux->offload->jited_len; 310 if (info->jited_prog_len & ulen) { 311 uinsns = u64_to_user_ptr(info->jited_prog_insns); 312 ulen = min_t(u32, info->jited_prog_len, ulen); 313 if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) { 314 up_read(&bpf_devs_lock); 315 return -EFAULT; 316 } 317 } 318 319 up_read(&bpf_devs_lock); 320 321 ns_inode = ns_path.dentry->d_inode; 322 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); 323 info->netns_ino = ns_inode->i_ino; 324 path_put(&ns_path); 325 326 return 0; 327 } 328 329 const struct bpf_prog_ops bpf_offload_prog_ops = { 330 }; 331 332 static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap, 333 enum bpf_netdev_command cmd) 334 { 335 struct netdev_bpf data = {}; 336 struct net_device *netdev; 337 338 ASSERT_RTNL(); 339 340 data.command = cmd; 341 data.offmap = offmap; 342 /* Caller must make sure netdev is valid */ 343 netdev = offmap->netdev; 344 345 return netdev->netdev_ops->ndo_bpf(netdev, &data); 346 } 347 348 struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr) 349 { 350 struct net *net = current->nsproxy->net_ns; 351 struct bpf_offload_netdev *ondev; 352 struct bpf_offloaded_map *offmap; 353 int err; 354 355 if (!capable(CAP_SYS_ADMIN)) 356 return ERR_PTR(-EPERM); 357 if (attr->map_type != BPF_MAP_TYPE_ARRAY && 358 attr->map_type != BPF_MAP_TYPE_HASH) 359 return ERR_PTR(-EINVAL); 360 361 offmap = kzalloc(sizeof(*offmap), GFP_USER); 362 if (!offmap) 363 return ERR_PTR(-ENOMEM); 364 365 bpf_map_init_from_attr(&offmap->map, attr); 366 367 rtnl_lock(); 368 down_write(&bpf_devs_lock); 369 offmap->netdev = __dev_get_by_index(net, attr->map_ifindex); 370 err = bpf_dev_offload_check(offmap->netdev); 371 if (err) 372 goto err_unlock; 373 374 ondev = bpf_offload_find_netdev(offmap->netdev); 375 if (!ondev) { 376 err = -EINVAL; 377 goto err_unlock; 378 } 379 380 err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC); 381 if (err) 382 goto err_unlock; 383 384 list_add_tail(&offmap->offloads, &ondev->maps); 385 up_write(&bpf_devs_lock); 386 rtnl_unlock(); 387 388 return &offmap->map; 389 390 err_unlock: 391 up_write(&bpf_devs_lock); 392 rtnl_unlock(); 393 kfree(offmap); 394 return ERR_PTR(err); 395 } 396 397 static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap) 398 { 399 WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE)); 400 /* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */ 401 bpf_map_free_id(&offmap->map, true); 402 list_del_init(&offmap->offloads); 403 offmap->netdev = NULL; 404 } 405 406 void bpf_map_offload_map_free(struct bpf_map *map) 407 { 408 struct bpf_offloaded_map *offmap = map_to_offmap(map); 409 410 rtnl_lock(); 411 down_write(&bpf_devs_lock); 412 if (offmap->netdev) 413 __bpf_map_offload_destroy(offmap); 414 up_write(&bpf_devs_lock); 415 rtnl_unlock(); 416 417 kfree(offmap); 418 } 419 420 int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value) 421 { 422 struct bpf_offloaded_map *offmap = map_to_offmap(map); 423 int ret = -ENODEV; 424 425 down_read(&bpf_devs_lock); 426 if (offmap->netdev) 427 ret = offmap->dev_ops->map_lookup_elem(offmap, key, value); 428 up_read(&bpf_devs_lock); 429 430 return ret; 431 } 432 433 int bpf_map_offload_update_elem(struct bpf_map *map, 434 void *key, void *value, u64 flags) 435 { 436 struct bpf_offloaded_map *offmap = map_to_offmap(map); 437 int ret = -ENODEV; 438 439 if (unlikely(flags > BPF_EXIST)) 440 return -EINVAL; 441 442 down_read(&bpf_devs_lock); 443 if (offmap->netdev) 444 ret = offmap->dev_ops->map_update_elem(offmap, key, value, 445 flags); 446 up_read(&bpf_devs_lock); 447 448 return ret; 449 } 450 451 int bpf_map_offload_delete_elem(struct bpf_map *map, void *key) 452 { 453 struct bpf_offloaded_map *offmap = map_to_offmap(map); 454 int ret = -ENODEV; 455 456 down_read(&bpf_devs_lock); 457 if (offmap->netdev) 458 ret = offmap->dev_ops->map_delete_elem(offmap, key); 459 up_read(&bpf_devs_lock); 460 461 return ret; 462 } 463 464 int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key) 465 { 466 struct bpf_offloaded_map *offmap = map_to_offmap(map); 467 int ret = -ENODEV; 468 469 down_read(&bpf_devs_lock); 470 if (offmap->netdev) 471 ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key); 472 up_read(&bpf_devs_lock); 473 474 return ret; 475 } 476 477 struct ns_get_path_bpf_map_args { 478 struct bpf_offloaded_map *offmap; 479 struct bpf_map_info *info; 480 }; 481 482 static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data) 483 { 484 struct ns_get_path_bpf_map_args *args = private_data; 485 struct ns_common *ns; 486 struct net *net; 487 488 rtnl_lock(); 489 down_read(&bpf_devs_lock); 490 491 if (args->offmap->netdev) { 492 args->info->ifindex = args->offmap->netdev->ifindex; 493 net = dev_net(args->offmap->netdev); 494 get_net(net); 495 ns = &net->ns; 496 } else { 497 args->info->ifindex = 0; 498 ns = NULL; 499 } 500 501 up_read(&bpf_devs_lock); 502 rtnl_unlock(); 503 504 return ns; 505 } 506 507 int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map) 508 { 509 struct ns_get_path_bpf_map_args args = { 510 .offmap = map_to_offmap(map), 511 .info = info, 512 }; 513 struct inode *ns_inode; 514 struct path ns_path; 515 void *res; 516 517 res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args); 518 if (IS_ERR(res)) { 519 if (!info->ifindex) 520 return -ENODEV; 521 return PTR_ERR(res); 522 } 523 524 ns_inode = ns_path.dentry->d_inode; 525 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); 526 info->netns_ino = ns_inode->i_ino; 527 path_put(&ns_path); 528 529 return 0; 530 } 531 532 static bool __bpf_offload_dev_match(struct bpf_prog *prog, 533 struct net_device *netdev) 534 { 535 struct bpf_offload_netdev *ondev1, *ondev2; 536 struct bpf_prog_offload *offload; 537 538 if (!bpf_prog_is_dev_bound(prog->aux)) 539 return false; 540 541 offload = prog->aux->offload; 542 if (!offload) 543 return false; 544 if (offload->netdev == netdev) 545 return true; 546 547 ondev1 = bpf_offload_find_netdev(offload->netdev); 548 ondev2 = bpf_offload_find_netdev(netdev); 549 550 return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev; 551 } 552 553 bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev) 554 { 555 bool ret; 556 557 down_read(&bpf_devs_lock); 558 ret = __bpf_offload_dev_match(prog, netdev); 559 up_read(&bpf_devs_lock); 560 561 return ret; 562 } 563 EXPORT_SYMBOL_GPL(bpf_offload_dev_match); 564 565 bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map) 566 { 567 struct bpf_offloaded_map *offmap; 568 bool ret; 569 570 if (!bpf_map_is_dev_bound(map)) 571 return bpf_map_offload_neutral(map); 572 offmap = map_to_offmap(map); 573 574 down_read(&bpf_devs_lock); 575 ret = __bpf_offload_dev_match(prog, offmap->netdev); 576 up_read(&bpf_devs_lock); 577 578 return ret; 579 } 580 581 int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev, 582 struct net_device *netdev) 583 { 584 struct bpf_offload_netdev *ondev; 585 int err; 586 587 ondev = kzalloc(sizeof(*ondev), GFP_KERNEL); 588 if (!ondev) 589 return -ENOMEM; 590 591 ondev->netdev = netdev; 592 ondev->offdev = offdev; 593 INIT_LIST_HEAD(&ondev->progs); 594 INIT_LIST_HEAD(&ondev->maps); 595 596 down_write(&bpf_devs_lock); 597 err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params); 598 if (err) { 599 netdev_warn(netdev, "failed to register for BPF offload\n"); 600 goto err_unlock_free; 601 } 602 603 list_add(&ondev->offdev_netdevs, &offdev->netdevs); 604 up_write(&bpf_devs_lock); 605 return 0; 606 607 err_unlock_free: 608 up_write(&bpf_devs_lock); 609 kfree(ondev); 610 return err; 611 } 612 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register); 613 614 void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev, 615 struct net_device *netdev) 616 { 617 struct bpf_offload_netdev *ondev, *altdev; 618 struct bpf_offloaded_map *offmap, *mtmp; 619 struct bpf_prog_offload *offload, *ptmp; 620 621 ASSERT_RTNL(); 622 623 down_write(&bpf_devs_lock); 624 ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params); 625 if (WARN_ON(!ondev)) 626 goto unlock; 627 628 WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params)); 629 list_del(&ondev->offdev_netdevs); 630 631 /* Try to move the objects to another netdev of the device */ 632 altdev = list_first_entry_or_null(&offdev->netdevs, 633 struct bpf_offload_netdev, 634 offdev_netdevs); 635 if (altdev) { 636 list_for_each_entry(offload, &ondev->progs, offloads) 637 offload->netdev = altdev->netdev; 638 list_splice_init(&ondev->progs, &altdev->progs); 639 640 list_for_each_entry(offmap, &ondev->maps, offloads) 641 offmap->netdev = altdev->netdev; 642 list_splice_init(&ondev->maps, &altdev->maps); 643 } else { 644 list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads) 645 __bpf_prog_offload_destroy(offload->prog); 646 list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads) 647 __bpf_map_offload_destroy(offmap); 648 } 649 650 WARN_ON(!list_empty(&ondev->progs)); 651 WARN_ON(!list_empty(&ondev->maps)); 652 kfree(ondev); 653 unlock: 654 up_write(&bpf_devs_lock); 655 } 656 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister); 657 658 struct bpf_offload_dev *bpf_offload_dev_create(void) 659 { 660 struct bpf_offload_dev *offdev; 661 int err; 662 663 down_write(&bpf_devs_lock); 664 if (!offdevs_inited) { 665 err = rhashtable_init(&offdevs, &offdevs_params); 666 if (err) 667 return ERR_PTR(err); 668 offdevs_inited = true; 669 } 670 up_write(&bpf_devs_lock); 671 672 offdev = kzalloc(sizeof(*offdev), GFP_KERNEL); 673 if (!offdev) 674 return ERR_PTR(-ENOMEM); 675 676 INIT_LIST_HEAD(&offdev->netdevs); 677 678 return offdev; 679 } 680 EXPORT_SYMBOL_GPL(bpf_offload_dev_create); 681 682 void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev) 683 { 684 WARN_ON(!list_empty(&offdev->netdevs)); 685 kfree(offdev); 686 } 687 EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy); 688