개념 설명 전체 · v6.18.37 / net/core/net_namespace.c
1 // SPDX-License-Identifier: GPL-2.0-only 2 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 3 4 #include <linux/workqueue.h> 5 #include <linux/rtnetlink.h> 6 #include <linux/cache.h> 7 #include <linux/slab.h> 8 #include <linux/list.h> 9 #include <linux/delay.h> 10 #include <linux/sched.h> 11 #include <linux/idr.h> 12 #include <linux/rculist.h> 13 #include <linux/nsproxy.h> 14 #include <linux/fs.h> 15 #include <linux/proc_ns.h> 16 #include <linux/file.h> 17 #include <linux/export.h> 18 #include <linux/user_namespace.h> 19 #include <linux/net_namespace.h> 20 #include <linux/sched/task.h> 21 #include <linux/uidgid.h> 22 #include <linux/proc_fs.h> 23 #include <linux/nstree.h> 24 25 #include <net/aligned_data.h> 26 #include <net/sock.h> 27 #include <net/netlink.h> 28 #include <net/net_namespace.h> 29 #include <net/netns/generic.h> 30 31 /* 32 * Our network namespace constructor/destructor lists 33 */ 34 35 static LIST_HEAD(pernet_list); 36 static struct list_head *first_device = &pernet_list; 37 38 LIST_HEAD(net_namespace_list); 39 EXPORT_SYMBOL_GPL(net_namespace_list); 40 41 /* Protects net_namespace_list. Nests iside rtnl_lock() */ 42 DECLARE_RWSEM(net_rwsem); 43 EXPORT_SYMBOL_GPL(net_rwsem); 44 45 #ifdef CONFIG_KEYS 46 static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) }; 47 #endif 48 49 struct net init_net; 50 EXPORT_SYMBOL(init_net); 51 52 static bool init_net_initialized; 53 /* 54 * pernet_ops_rwsem: protects: pernet_list, net_generic_ids, 55 * init_net_initialized and first_device pointer. 56 * This is internal net namespace object. Please, don't use it 57 * outside. 58 */ 59 DECLARE_RWSEM(pernet_ops_rwsem); 60 61 #define MIN_PERNET_OPS_ID \ 62 ((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *)) 63 64 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */ 65 66 static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS; 67 68 static struct net_generic *net_alloc_generic(void) 69 { 70 unsigned int gen_ptrs = READ_ONCE(max_gen_ptrs); 71 unsigned int generic_size; 72 struct net_generic *ng; 73 74 generic_size = offsetof(struct net_generic, ptr[gen_ptrs]); 75 76 ng = kzalloc(generic_size, GFP_KERNEL); 77 if (ng) 78 ng->s.len = gen_ptrs; 79 80 return ng; 81 } 82 83 static int net_assign_generic(struct net *net, unsigned int id, void *data) 84 { 85 struct net_generic *ng, *old_ng; 86 87 BUG_ON(id < MIN_PERNET_OPS_ID); 88 89 old_ng = rcu_dereference_protected(net->gen, 90 lockdep_is_held(&pernet_ops_rwsem)); 91 if (old_ng->s.len > id) { 92 old_ng->ptr[id] = data; 93 return 0; 94 } 95 96 ng = net_alloc_generic(); 97 if (!ng) 98 return -ENOMEM; 99 100 /* 101 * Some synchronisation notes: 102 * 103 * The net_generic explores the net->gen array inside rcu 104 * read section. Besides once set the net->gen->ptr[x] 105 * pointer never changes (see rules in netns/generic.h). 106 * 107 * That said, we simply duplicate this array and schedule 108 * the old copy for kfree after a grace period. 109 */ 110 111 memcpy(&ng->ptr[MIN_PERNET_OPS_ID], &old_ng->ptr[MIN_PERNET_OPS_ID], 112 (old_ng->s.len - MIN_PERNET_OPS_ID) * sizeof(void *)); 113 ng->ptr[id] = data; 114 115 rcu_assign_pointer(net->gen, ng); 116 kfree_rcu(old_ng, s.rcu); 117 return 0; 118 } 119 120 static int ops_init(const struct pernet_operations *ops, struct net *net) 121 { 122 struct net_generic *ng; 123 int err = -ENOMEM; 124 void *data = NULL; 125 126 if (ops->id) { 127 data = kzalloc(ops->size, GFP_KERNEL); 128 if (!data) 129 goto out; 130 131 err = net_assign_generic(net, *ops->id, data); 132 if (err) 133 goto cleanup; 134 } 135 err = 0; 136 if (ops->init) 137 err = ops->init(net); 138 if (!err) 139 return 0; 140 141 if (ops->id) { 142 ng = rcu_dereference_protected(net->gen, 143 lockdep_is_held(&pernet_ops_rwsem)); 144 ng->ptr[*ops->id] = NULL; 145 } 146 147 cleanup: 148 kfree(data); 149 150 out: 151 return err; 152 } 153 154 static void ops_pre_exit_list(const struct pernet_operations *ops, 155 struct list_head *net_exit_list) 156 { 157 struct net *net; 158 159 if (ops->pre_exit) { 160 list_for_each_entry(net, net_exit_list, exit_list) 161 ops->pre_exit(net); 162 } 163 } 164 165 static void ops_exit_rtnl_list(const struct list_head *ops_list, 166 const struct pernet_operations *ops, 167 struct list_head *net_exit_list) 168 { 169 const struct pernet_operations *saved_ops = ops; 170 LIST_HEAD(dev_kill_list); 171 struct net *net; 172 173 rtnl_lock(); 174 175 list_for_each_entry(net, net_exit_list, exit_list) { 176 __rtnl_net_lock(net); 177 178 ops = saved_ops; 179 list_for_each_entry_continue_reverse(ops, ops_list, list) { 180 if (ops->exit_rtnl) 181 ops->exit_rtnl(net, &dev_kill_list); 182 } 183 184 __rtnl_net_unlock(net); 185 } 186 187 unregister_netdevice_many(&dev_kill_list); 188 189 rtnl_unlock(); 190 } 191 192 static void ops_exit_list(const struct pernet_operations *ops, 193 struct list_head *net_exit_list) 194 { 195 if (ops->exit) { 196 struct net *net; 197 198 list_for_each_entry(net, net_exit_list, exit_list) { 199 ops->exit(net); 200 cond_resched(); 201 } 202 } 203 204 if (ops->exit_batch) 205 ops->exit_batch(net_exit_list); 206 } 207 208 static void ops_free_list(const struct pernet_operations *ops, 209 struct list_head *net_exit_list) 210 { 211 struct net *net; 212 213 if (ops->id) { 214 list_for_each_entry(net, net_exit_list, exit_list) 215 kfree(net_generic(net, *ops->id)); 216 } 217 } 218 219 static void ops_undo_list(const struct list_head *ops_list, 220 const struct pernet_operations *ops, 221 struct list_head *net_exit_list, 222 bool expedite_rcu) 223 { 224 const struct pernet_operations *saved_ops; 225 bool hold_rtnl = false; 226 227 if (!ops) 228 ops = list_entry(ops_list, typeof(*ops), list); 229 230 saved_ops = ops; 231 232 list_for_each_entry_continue_reverse(ops, ops_list, list) { 233 hold_rtnl |= !!ops->exit_rtnl; 234 ops_pre_exit_list(ops, net_exit_list); 235 } 236 237 /* Another CPU might be rcu-iterating the list, wait for it. 238 * This needs to be before calling the exit() notifiers, so the 239 * rcu_barrier() after ops_undo_list() isn't sufficient alone. 240 * Also the pre_exit() and exit() methods need this barrier. 241 */ 242 if (expedite_rcu) 243 synchronize_rcu_expedited(); 244 else 245 synchronize_rcu(); 246 247 if (hold_rtnl) 248 ops_exit_rtnl_list(ops_list, saved_ops, net_exit_list); 249 250 ops = saved_ops; 251 list_for_each_entry_continue_reverse(ops, ops_list, list) 252 ops_exit_list(ops, net_exit_list); 253 254 ops = saved_ops; 255 list_for_each_entry_continue_reverse(ops, ops_list, list) 256 ops_free_list(ops, net_exit_list); 257 } 258 259 static void ops_undo_single(struct pernet_operations *ops, 260 struct list_head *net_exit_list) 261 { 262 LIST_HEAD(ops_list); 263 264 list_add(&ops->list, &ops_list); 265 ops_undo_list(&ops_list, NULL, net_exit_list, false); 266 list_del(&ops->list); 267 } 268 269 /* should be called with nsid_lock held */ 270 static int alloc_netid(struct net *net, struct net *peer, int reqid) 271 { 272 int min = 0, max = 0; 273 274 if (reqid >= 0) { 275 min = reqid; 276 max = reqid + 1; 277 } 278 279 return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC); 280 } 281 282 /* This function is used by idr_for_each(). If net is equal to peer, the 283 * function returns the id so that idr_for_each() stops. Because we cannot 284 * returns the id 0 (idr_for_each() will not stop), we return the magic value 285 * NET_ID_ZERO (-1) for it. 286 */ 287 #define NET_ID_ZERO -1 288 static int net_eq_idr(int id, void *net, void *peer) 289 { 290 if (net_eq(net, peer)) 291 return id ? : NET_ID_ZERO; 292 return 0; 293 } 294 295 /* Must be called from RCU-critical section or with nsid_lock held */ 296 static int __peernet2id(const struct net *net, struct net *peer) 297 { 298 int id = idr_for_each(&net->netns_ids, net_eq_idr, peer); 299 300 /* Magic value for id 0. */ 301 if (id == NET_ID_ZERO) 302 return 0; 303 if (id > 0) 304 return id; 305 306 return NETNSA_NSID_NOT_ASSIGNED; 307 } 308 309 static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, 310 struct nlmsghdr *nlh, gfp_t gfp); 311 /* This function returns the id of a peer netns. If no id is assigned, one will 312 * be allocated and returned. 313 */ 314 int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp) 315 { 316 int id; 317 318 if (!check_net(net)) 319 return NETNSA_NSID_NOT_ASSIGNED; 320 321 spin_lock(&net->nsid_lock); 322 id = __peernet2id(net, peer); 323 if (id >= 0) { 324 spin_unlock(&net->nsid_lock); 325 return id; 326 } 327 328 /* When peer is obtained from RCU lists, we may race with 329 * its cleanup. Check whether it's alive, and this guarantees 330 * we never hash a peer back to net->netns_ids, after it has 331 * just been idr_remove()'d from there in cleanup_net(). 332 */ 333 if (!maybe_get_net(peer)) { 334 spin_unlock(&net->nsid_lock); 335 return NETNSA_NSID_NOT_ASSIGNED; 336 } 337 338 id = alloc_netid(net, peer, -1); 339 spin_unlock(&net->nsid_lock); 340 341 put_net(peer); 342 if (id < 0) 343 return NETNSA_NSID_NOT_ASSIGNED; 344 345 rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL, gfp); 346 347 return id; 348 } 349 EXPORT_SYMBOL_GPL(peernet2id_alloc); 350 351 /* This function returns, if assigned, the id of a peer netns. */ 352 int peernet2id(const struct net *net, struct net *peer) 353 { 354 int id; 355 356 rcu_read_lock(); 357 id = __peernet2id(net, peer); 358 rcu_read_unlock(); 359 360 return id; 361 } 362 EXPORT_SYMBOL(peernet2id); 363 364 /* This function returns true is the peer netns has an id assigned into the 365 * current netns. 366 */ 367 bool peernet_has_id(const struct net *net, struct net *peer) 368 { 369 return peernet2id(net, peer) >= 0; 370 } 371 372 struct net *get_net_ns_by_id(const struct net *net, int id) 373 { 374 struct net *peer; 375 376 if (id < 0) 377 return NULL; 378 379 rcu_read_lock(); 380 peer = idr_find(&net->netns_ids, id); 381 if (peer) 382 peer = maybe_get_net(peer); 383 rcu_read_unlock(); 384 385 return peer; 386 } 387 EXPORT_SYMBOL_GPL(get_net_ns_by_id); 388 389 static __net_init void preinit_net_sysctl(struct net *net) 390 { 391 net->core.sysctl_somaxconn = SOMAXCONN; 392 /* Limits per socket sk_omem_alloc usage. 393 * TCP zerocopy regular usage needs 128 KB. 394 */ 395 net->core.sysctl_optmem_max = 128 * 1024; 396 net->core.sysctl_txrehash = SOCK_TXREHASH_ENABLED; 397 net->core.sysctl_tstamp_allow_data = 1; 398 } 399 400 /* init code that must occur even if setup_net() is not called. */ 401 static __net_init int preinit_net(struct net *net, struct user_namespace *user_ns) 402 { 403 int ret; 404 405 ret = ns_common_init(net); 406 if (ret) 407 return ret; 408 409 refcount_set(&net->passive, 1); 410 ref_tracker_dir_init(&net->refcnt_tracker, 128, "net_refcnt"); 411 ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net_notrefcnt"); 412 413 get_random_bytes(&net->hash_mix, sizeof(u32)); 414 net->dev_base_seq = 1; 415 net->user_ns = user_ns; 416 417 idr_init(&net->netns_ids); 418 spin_lock_init(&net->nsid_lock); 419 mutex_init(&net->ipv4.ra_mutex); 420 421 #ifdef CONFIG_DEBUG_NET_SMALL_RTNL 422 mutex_init(&net->rtnl_mutex); 423 lock_set_cmp_fn(&net->rtnl_mutex, rtnl_net_lock_cmp_fn, NULL); 424 #endif 425 426 INIT_LIST_HEAD(&net->ptype_all); 427 INIT_LIST_HEAD(&net->ptype_specific); 428 preinit_net_sysctl(net); 429 return 0; 430 } 431 432 /* 433 * setup_net runs the initializers for the network namespace object. 434 */ 435 static __net_init int setup_net(struct net *net) 436 { 437 /* Must be called with pernet_ops_rwsem held */ 438 const struct pernet_operations *ops; 439 LIST_HEAD(net_exit_list); 440 int error = 0; 441 442 net->net_cookie = ns_tree_gen_id(&net->ns); 443 444 list_for_each_entry(ops, &pernet_list, list) { 445 error = ops_init(ops, net); 446 if (error < 0) 447 goto out_undo; 448 } 449 down_write(&net_rwsem); 450 list_add_tail_rcu(&net->list, &net_namespace_list); 451 up_write(&net_rwsem); 452 ns_tree_add_raw(net); 453 out: 454 return error; 455 456 out_undo: 457 /* Walk through the list backwards calling the exit functions 458 * for the pernet modules whose init functions did not fail. 459 */ 460 list_add(&net->exit_list, &net_exit_list); 461 ops_undo_list(&pernet_list, ops, &net_exit_list, false); 462 rcu_barrier(); 463 goto out; 464 } 465 466 #ifdef CONFIG_NET_NS 467 static struct ucounts *inc_net_namespaces(struct user_namespace *ns) 468 { 469 return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES); 470 } 471 472 static void dec_net_namespaces(struct ucounts *ucounts) 473 { 474 dec_ucount(ucounts, UCOUNT_NET_NAMESPACES); 475 } 476 477 static struct kmem_cache *net_cachep __ro_after_init; 478 static struct workqueue_struct *netns_wq; 479 480 static struct net *net_alloc(void) 481 { 482 struct net *net = NULL; 483 struct net_generic *ng; 484 485 ng = net_alloc_generic(); 486 if (!ng) 487 goto out; 488 489 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL); 490 if (!net) 491 goto out_free; 492 493 #ifdef CONFIG_KEYS 494 net->key_domain = kzalloc(sizeof(struct key_tag), GFP_KERNEL); 495 if (!net->key_domain) 496 goto out_free_2; 497 refcount_set(&net->key_domain->usage, 1); 498 #endif 499 500 rcu_assign_pointer(net->gen, ng); 501 out: 502 return net; 503 504 #ifdef CONFIG_KEYS 505 out_free_2: 506 kmem_cache_free(net_cachep, net); 507 net = NULL; 508 #endif 509 out_free: 510 kfree(ng); 511 goto out; 512 } 513 514 static LLIST_HEAD(defer_free_list); 515 516 static void net_complete_free(void) 517 { 518 struct llist_node *kill_list; 519 struct net *net, *next; 520 521 /* Get the list of namespaces to free from last round. */ 522 kill_list = llist_del_all(&defer_free_list); 523 524 llist_for_each_entry_safe(net, next, kill_list, defer_free_list) 525 kmem_cache_free(net_cachep, net); 526 527 } 528 529 void net_passive_dec(struct net *net) 530 { 531 if (refcount_dec_and_test(&net->passive)) { 532 kfree(rcu_access_pointer(net->gen)); 533 534 /* There should not be any trackers left there. */ 535 ref_tracker_dir_exit(&net->notrefcnt_tracker); 536 537 /* Wait for an extra rcu_barrier() before final free. */ 538 llist_add(&net->defer_free_list, &defer_free_list); 539 } 540 } 541 542 void net_drop_ns(void *p) 543 { 544 struct net *net = (struct net *)p; 545 546 if (net) 547 net_passive_dec(net); 548 } 549 550 struct net *copy_net_ns(u64 flags, 551 struct user_namespace *user_ns, struct net *old_net) 552 { 553 struct ucounts *ucounts; 554 struct net *net; 555 int rv; 556 557 if (!(flags & CLONE_NEWNET)) 558 return get_net(old_net); 559 560 ucounts = inc_net_namespaces(user_ns); 561 if (!ucounts) 562 return ERR_PTR(-ENOSPC); 563 564 net = net_alloc(); 565 if (!net) { 566 rv = -ENOMEM; 567 goto dec_ucounts; 568 } 569 570 rv = preinit_net(net, user_ns); 571 if (rv < 0) 572 goto dec_ucounts; 573 net->ucounts = ucounts; 574 get_user_ns(user_ns); 575 576 rv = down_read_killable(&pernet_ops_rwsem); 577 if (rv < 0) 578 goto put_userns; 579 580 rv = setup_net(net); 581 582 up_read(&pernet_ops_rwsem); 583 584 if (rv < 0) { 585 put_userns: 586 ns_common_free(net); 587 #ifdef CONFIG_KEYS 588 key_remove_domain(net->key_domain); 589 #endif 590 put_user_ns(user_ns); 591 net_passive_dec(net); 592 dec_ucounts: 593 dec_net_namespaces(ucounts); 594 return ERR_PTR(rv); 595 } 596 return net; 597 } 598 599 /** 600 * net_ns_get_ownership - get sysfs ownership data for @net 601 * @net: network namespace in question (can be NULL) 602 * @uid: kernel user ID for sysfs objects 603 * @gid: kernel group ID for sysfs objects 604 * 605 * Returns the uid/gid pair of root in the user namespace associated with the 606 * given network namespace. 607 */ 608 void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid) 609 { 610 if (net) { 611 kuid_t ns_root_uid = make_kuid(net->user_ns, 0); 612 kgid_t ns_root_gid = make_kgid(net->user_ns, 0); 613 614 if (uid_valid(ns_root_uid)) 615 *uid = ns_root_uid; 616 617 if (gid_valid(ns_root_gid)) 618 *gid = ns_root_gid; 619 } else { 620 *uid = GLOBAL_ROOT_UID; 621 *gid = GLOBAL_ROOT_GID; 622 } 623 } 624 EXPORT_SYMBOL_GPL(net_ns_get_ownership); 625 626 static void unhash_nsid(struct net *net, struct net *last) 627 { 628 struct net *tmp; 629 /* This function is only called from cleanup_net() work, 630 * and this work is the only process, that may delete 631 * a net from net_namespace_list. So, when the below 632 * is executing, the list may only grow. Thus, we do not 633 * use for_each_net_rcu() or net_rwsem. 634 */ 635 for_each_net(tmp) { 636 int id; 637 638 spin_lock(&tmp->nsid_lock); 639 id = __peernet2id(tmp, net); 640 if (id >= 0) 641 idr_remove(&tmp->netns_ids, id); 642 spin_unlock(&tmp->nsid_lock); 643 if (id >= 0) 644 rtnl_net_notifyid(tmp, RTM_DELNSID, id, 0, NULL, 645 GFP_KERNEL); 646 if (tmp == last) 647 break; 648 } 649 spin_lock(&net->nsid_lock); 650 idr_destroy(&net->netns_ids); 651 spin_unlock(&net->nsid_lock); 652 } 653 654 static LLIST_HEAD(cleanup_list); 655 656 struct task_struct *cleanup_net_task; 657 658 static void cleanup_net(struct work_struct *work) 659 { 660 struct llist_node *net_kill_list; 661 struct net *net, *tmp, *last; 662 LIST_HEAD(net_exit_list); 663 664 WRITE_ONCE(cleanup_net_task, current); 665 666 /* Atomically snapshot the list of namespaces to cleanup */ 667 net_kill_list = llist_del_all(&cleanup_list); 668 669 down_read(&pernet_ops_rwsem); 670 671 /* Don't let anyone else find us. */ 672 down_write(&net_rwsem); 673 llist_for_each_entry(net, net_kill_list, cleanup_list) { 674 ns_tree_remove(net); 675 list_del_rcu(&net->list); 676 } 677 /* Cache last net. After we unlock rtnl, no one new net 678 * added to net_namespace_list can assign nsid pointer 679 * to a net from net_kill_list (see peernet2id_alloc()). 680 * So, we skip them in unhash_nsid(). 681 * 682 * Note, that unhash_nsid() does not delete nsid links 683 * between net_kill_list's nets, as they've already 684 * deleted from net_namespace_list. But, this would be 685 * useless anyway, as netns_ids are destroyed there. 686 */ 687 last = list_last_entry(&net_namespace_list, struct net, list); 688 up_write(&net_rwsem); 689 690 llist_for_each_entry(net, net_kill_list, cleanup_list) { 691 unhash_nsid(net, last); 692 list_add_tail(&net->exit_list, &net_exit_list); 693 } 694 695 ops_undo_list(&pernet_list, NULL, &net_exit_list, true); 696 697 up_read(&pernet_ops_rwsem); 698 699 /* Ensure there are no outstanding rcu callbacks using this 700 * network namespace. 701 */ 702 rcu_barrier(); 703 704 net_complete_free(); 705 706 /* Finally it is safe to free my network namespace structure */ 707 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { 708 list_del_init(&net->exit_list); 709 ns_common_free(net); 710 dec_net_namespaces(net->ucounts); 711 #ifdef CONFIG_KEYS 712 key_remove_domain(net->key_domain); 713 #endif 714 put_user_ns(net->user_ns); 715 net_passive_dec(net); 716 } 717 WRITE_ONCE(cleanup_net_task, NULL); 718 } 719 720 /** 721 * net_ns_barrier - wait until concurrent net_cleanup_work is done 722 * 723 * cleanup_net runs from work queue and will first remove namespaces 724 * from the global list, then run net exit functions. 725 * 726 * Call this in module exit path to make sure that all netns 727 * ->exit ops have been invoked before the function is removed. 728 */ 729 void net_ns_barrier(void) 730 { 731 down_write(&pernet_ops_rwsem); 732 up_write(&pernet_ops_rwsem); 733 } 734 EXPORT_SYMBOL(net_ns_barrier); 735 736 static DECLARE_WORK(net_cleanup_work, cleanup_net); 737 738 void __put_net(struct net *net) 739 { 740 ref_tracker_dir_exit(&net->refcnt_tracker); 741 /* Cleanup the network namespace in process context */ 742 if (llist_add(&net->cleanup_list, &cleanup_list)) 743 queue_work(netns_wq, &net_cleanup_work); 744 } 745 EXPORT_SYMBOL_GPL(__put_net); 746 747 /** 748 * get_net_ns - increment the refcount of the network namespace 749 * @ns: common namespace (net) 750 * 751 * Returns the net's common namespace or ERR_PTR() if ref is zero. 752 */ 753 struct ns_common *get_net_ns(struct ns_common *ns) 754 { 755 struct net *net; 756 757 net = maybe_get_net(container_of(ns, struct net, ns)); 758 if (net) 759 return &net->ns; 760 return ERR_PTR(-EINVAL); 761 } 762 EXPORT_SYMBOL_GPL(get_net_ns); 763 764 struct net *get_net_ns_by_fd(int fd) 765 { 766 CLASS(fd, f)(fd); 767 768 if (fd_empty(f)) 769 return ERR_PTR(-EBADF); 770 771 if (proc_ns_file(fd_file(f))) { 772 struct ns_common *ns = get_proc_ns(file_inode(fd_file(f))); 773 if (ns->ops == &netns_operations) 774 return get_net(container_of(ns, struct net, ns)); 775 } 776 777 return ERR_PTR(-EINVAL); 778 } 779 EXPORT_SYMBOL_GPL(get_net_ns_by_fd); 780 #endif 781 782 struct net *get_net_ns_by_pid(pid_t pid) 783 { 784 struct task_struct *tsk; 785 struct net *net; 786 787 /* Lookup the network namespace */ 788 net = ERR_PTR(-ESRCH); 789 rcu_read_lock(); 790 tsk = find_task_by_vpid(pid); 791 if (tsk) { 792 struct nsproxy *nsproxy; 793 task_lock(tsk); 794 nsproxy = tsk->nsproxy; 795 if (nsproxy) 796 net = get_net(nsproxy->net_ns); 797 task_unlock(tsk); 798 } 799 rcu_read_unlock(); 800 return net; 801 } 802 EXPORT_SYMBOL_GPL(get_net_ns_by_pid); 803 804 #ifdef CONFIG_NET_NS_REFCNT_TRACKER 805 static void net_ns_net_debugfs(struct net *net) 806 { 807 ref_tracker_dir_symlink(&net->refcnt_tracker, "netns-%llx-%u-refcnt", 808 net->net_cookie, net->ns.inum); 809 ref_tracker_dir_symlink(&net->notrefcnt_tracker, "netns-%llx-%u-notrefcnt", 810 net->net_cookie, net->ns.inum); 811 } 812 813 static int __init init_net_debugfs(void) 814 { 815 ref_tracker_dir_debugfs(&init_net.refcnt_tracker); 816 ref_tracker_dir_debugfs(&init_net.notrefcnt_tracker); 817 net_ns_net_debugfs(&init_net); 818 return 0; 819 } 820 late_initcall(init_net_debugfs); 821 #else 822 static void net_ns_net_debugfs(struct net *net) 823 { 824 } 825 #endif 826 827 static __net_init int net_ns_net_init(struct net *net) 828 { 829 net_ns_net_debugfs(net); 830 return 0; 831 } 832 833 static struct pernet_operations __net_initdata net_ns_ops = { 834 .init = net_ns_net_init, 835 }; 836 837 static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = { 838 [NETNSA_NONE] = { .type = NLA_UNSPEC }, 839 [NETNSA_NSID] = { .type = NLA_S32 }, 840 [NETNSA_PID] = { .type = NLA_U32 }, 841 [NETNSA_FD] = { .type = NLA_U32 }, 842 [NETNSA_TARGET_NSID] = { .type = NLA_S32 }, 843 }; 844 845 static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh, 846 struct netlink_ext_ack *extack) 847 { 848 struct net *net = sock_net(skb->sk); 849 struct nlattr *tb[NETNSA_MAX + 1]; 850 struct nlattr *nla; 851 struct net *peer; 852 int nsid, err; 853 854 err = nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg), tb, 855 NETNSA_MAX, rtnl_net_policy, extack); 856 if (err < 0) 857 return err; 858 if (!tb[NETNSA_NSID]) { 859 NL_SET_ERR_MSG(extack, "nsid is missing"); 860 return -EINVAL; 861 } 862 nsid = nla_get_s32(tb[NETNSA_NSID]); 863 864 if (tb[NETNSA_PID]) { 865 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 866 nla = tb[NETNSA_PID]; 867 } else if (tb[NETNSA_FD]) { 868 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 869 nla = tb[NETNSA_FD]; 870 } else { 871 NL_SET_ERR_MSG(extack, "Peer netns reference is missing"); 872 return -EINVAL; 873 } 874 if (IS_ERR(peer)) { 875 NL_SET_BAD_ATTR(extack, nla); 876 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid"); 877 return PTR_ERR(peer); 878 } 879 880 spin_lock(&net->nsid_lock); 881 if (__peernet2id(net, peer) >= 0) { 882 spin_unlock(&net->nsid_lock); 883 err = -EEXIST; 884 NL_SET_BAD_ATTR(extack, nla); 885 NL_SET_ERR_MSG(extack, 886 "Peer netns already has a nsid assigned"); 887 goto out; 888 } 889 890 err = alloc_netid(net, peer, nsid); 891 spin_unlock(&net->nsid_lock); 892 if (err >= 0) { 893 rtnl_net_notifyid(net, RTM_NEWNSID, err, NETLINK_CB(skb).portid, 894 nlh, GFP_KERNEL); 895 err = 0; 896 } else if (err == -ENOSPC && nsid >= 0) { 897 err = -EEXIST; 898 NL_SET_BAD_ATTR(extack, tb[NETNSA_NSID]); 899 NL_SET_ERR_MSG(extack, "The specified nsid is already used"); 900 } 901 out: 902 put_net(peer); 903 return err; 904 } 905 906 static int rtnl_net_get_size(void) 907 { 908 return NLMSG_ALIGN(sizeof(struct rtgenmsg)) 909 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */ 910 + nla_total_size(sizeof(s32)) /* NETNSA_CURRENT_NSID */ 911 ; 912 } 913 914 struct net_fill_args { 915 u32 portid; 916 u32 seq; 917 int flags; 918 int cmd; 919 int nsid; 920 bool add_ref; 921 int ref_nsid; 922 }; 923 924 static int rtnl_net_fill(struct sk_buff *skb, struct net_fill_args *args) 925 { 926 struct nlmsghdr *nlh; 927 struct rtgenmsg *rth; 928 929 nlh = nlmsg_put(skb, args->portid, args->seq, args->cmd, sizeof(*rth), 930 args->flags); 931 if (!nlh) 932 return -EMSGSIZE; 933 934 rth = nlmsg_data(nlh); 935 rth->rtgen_family = AF_UNSPEC; 936 937 if (nla_put_s32(skb, NETNSA_NSID, args->nsid)) 938 goto nla_put_failure; 939 940 if (args->add_ref && 941 nla_put_s32(skb, NETNSA_CURRENT_NSID, args->ref_nsid)) 942 goto nla_put_failure; 943 944 nlmsg_end(skb, nlh); 945 return 0; 946 947 nla_put_failure: 948 nlmsg_cancel(skb, nlh); 949 return -EMSGSIZE; 950 } 951 952 static int rtnl_net_valid_getid_req(struct sk_buff *skb, 953 const struct nlmsghdr *nlh, 954 struct nlattr **tb, 955 struct netlink_ext_ack *extack) 956 { 957 int i, err; 958 959 if (!netlink_strict_get_check(skb)) 960 return nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg), 961 tb, NETNSA_MAX, rtnl_net_policy, 962 extack); 963 964 err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb, 965 NETNSA_MAX, rtnl_net_policy, 966 extack); 967 if (err) 968 return err; 969 970 for (i = 0; i <= NETNSA_MAX; i++) { 971 if (!tb[i]) 972 continue; 973 974 switch (i) { 975 case NETNSA_PID: 976 case NETNSA_FD: 977 case NETNSA_NSID: 978 case NETNSA_TARGET_NSID: 979 break; 980 default: 981 NL_SET_ERR_MSG(extack, "Unsupported attribute in peer netns getid request"); 982 return -EINVAL; 983 } 984 } 985 986 return 0; 987 } 988 989 static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh, 990 struct netlink_ext_ack *extack) 991 { 992 struct net *net = sock_net(skb->sk); 993 struct nlattr *tb[NETNSA_MAX + 1]; 994 struct net_fill_args fillargs = { 995 .portid = NETLINK_CB(skb).portid, 996 .seq = nlh->nlmsg_seq, 997 .cmd = RTM_NEWNSID, 998 }; 999 struct net *peer, *target = net; 1000 struct nlattr *nla; 1001 struct sk_buff *msg; 1002 int err; 1003 1004 err = rtnl_net_valid_getid_req(skb, nlh, tb, extack); 1005 if (err < 0) 1006 return err; 1007 if (tb[NETNSA_PID]) { 1008 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 1009 nla = tb[NETNSA_PID]; 1010 } else if (tb[NETNSA_FD]) { 1011 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 1012 nla = tb[NETNSA_FD]; 1013 } else if (tb[NETNSA_NSID]) { 1014 peer = get_net_ns_by_id(net, nla_get_s32(tb[NETNSA_NSID])); 1015 if (!peer) 1016 peer = ERR_PTR(-ENOENT); 1017 nla = tb[NETNSA_NSID]; 1018 } else { 1019 NL_SET_ERR_MSG(extack, "Peer netns reference is missing"); 1020 return -EINVAL; 1021 } 1022 1023 if (IS_ERR(peer)) { 1024 NL_SET_BAD_ATTR(extack, nla); 1025 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid"); 1026 return PTR_ERR(peer); 1027 } 1028 1029 if (tb[NETNSA_TARGET_NSID]) { 1030 int id = nla_get_s32(tb[NETNSA_TARGET_NSID]); 1031 1032 target = rtnl_get_net_ns_capable(NETLINK_CB(skb).sk, id); 1033 if (IS_ERR(target)) { 1034 NL_SET_BAD_ATTR(extack, tb[NETNSA_TARGET_NSID]); 1035 NL_SET_ERR_MSG(extack, 1036 "Target netns reference is invalid"); 1037 err = PTR_ERR(target); 1038 goto out; 1039 } 1040 fillargs.add_ref = true; 1041 fillargs.ref_nsid = peernet2id(net, peer); 1042 } 1043 1044 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 1045 if (!msg) { 1046 err = -ENOMEM; 1047 goto out; 1048 } 1049 1050 fillargs.nsid = peernet2id(target, peer); 1051 err = rtnl_net_fill(msg, &fillargs); 1052 if (err < 0) 1053 goto err_out; 1054 1055 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid); 1056 goto out; 1057 1058 err_out: 1059 nlmsg_free(msg); 1060 out: 1061 if (fillargs.add_ref) 1062 put_net(target); 1063 put_net(peer); 1064 return err; 1065 } 1066 1067 struct rtnl_net_dump_cb { 1068 struct net *tgt_net; 1069 struct net *ref_net; 1070 struct sk_buff *skb; 1071 struct net_fill_args fillargs; 1072 int idx; 1073 int s_idx; 1074 }; 1075 1076 /* Runs in RCU-critical section. */ 1077 static int rtnl_net_dumpid_one(int id, void *peer, void *data) 1078 { 1079 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data; 1080 int ret; 1081 1082 if (net_cb->idx < net_cb->s_idx) 1083 goto cont; 1084 1085 net_cb->fillargs.nsid = id; 1086 if (net_cb->fillargs.add_ref) 1087 net_cb->fillargs.ref_nsid = __peernet2id(net_cb->ref_net, peer); 1088 ret = rtnl_net_fill(net_cb->skb, &net_cb->fillargs); 1089 if (ret < 0) 1090 return ret; 1091 1092 cont: 1093 net_cb->idx++; 1094 return 0; 1095 } 1096 1097 static int rtnl_valid_dump_net_req(const struct nlmsghdr *nlh, struct sock *sk, 1098 struct rtnl_net_dump_cb *net_cb, 1099 struct netlink_callback *cb) 1100 { 1101 struct netlink_ext_ack *extack = cb->extack; 1102 struct nlattr *tb[NETNSA_MAX + 1]; 1103 int err, i; 1104 1105 err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb, 1106 NETNSA_MAX, rtnl_net_policy, 1107 extack); 1108 if (err < 0) 1109 return err; 1110 1111 for (i = 0; i <= NETNSA_MAX; i++) { 1112 if (!tb[i]) 1113 continue; 1114 1115 if (i == NETNSA_TARGET_NSID) { 1116 struct net *net; 1117 1118 net = rtnl_get_net_ns_capable(sk, nla_get_s32(tb[i])); 1119 if (IS_ERR(net)) { 1120 NL_SET_BAD_ATTR(extack, tb[i]); 1121 NL_SET_ERR_MSG(extack, 1122 "Invalid target network namespace id"); 1123 return PTR_ERR(net); 1124 } 1125 net_cb->fillargs.add_ref = true; 1126 net_cb->ref_net = net_cb->tgt_net; 1127 net_cb->tgt_net = net; 1128 } else { 1129 NL_SET_BAD_ATTR(extack, tb[i]); 1130 NL_SET_ERR_MSG(extack, 1131 "Unsupported attribute in dump request"); 1132 return -EINVAL; 1133 } 1134 } 1135 1136 return 0; 1137 } 1138 1139 static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb) 1140 { 1141 struct rtnl_net_dump_cb net_cb = { 1142 .tgt_net = sock_net(skb->sk), 1143 .skb = skb, 1144 .fillargs = { 1145 .portid = NETLINK_CB(cb->skb).portid, 1146 .seq = cb->nlh->nlmsg_seq, 1147 .flags = NLM_F_MULTI, 1148 .cmd = RTM_NEWNSID, 1149 }, 1150 .idx = 0, 1151 .s_idx = cb->args[0], 1152 }; 1153 int err = 0; 1154 1155 if (cb->strict_check) { 1156 err = rtnl_valid_dump_net_req(cb->nlh, skb->sk, &net_cb, cb); 1157 if (err < 0) 1158 goto end; 1159 } 1160 1161 rcu_read_lock(); 1162 idr_for_each(&net_cb.tgt_net->netns_ids, rtnl_net_dumpid_one, &net_cb); 1163 rcu_read_unlock(); 1164 1165 cb->args[0] = net_cb.idx; 1166 end: 1167 if (net_cb.fillargs.add_ref) 1168 put_net(net_cb.tgt_net); 1169 return err; 1170 } 1171 1172 static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, 1173 struct nlmsghdr *nlh, gfp_t gfp) 1174 { 1175 struct net_fill_args fillargs = { 1176 .portid = portid, 1177 .seq = nlh ? nlh->nlmsg_seq : 0, 1178 .cmd = cmd, 1179 .nsid = id, 1180 }; 1181 struct sk_buff *msg; 1182 int err = -ENOMEM; 1183 1184 msg = nlmsg_new(rtnl_net_get_size(), gfp); 1185 if (!msg) 1186 goto out; 1187 1188 err = rtnl_net_fill(msg, &fillargs); 1189 if (err < 0) 1190 goto err_out; 1191 1192 rtnl_notify(msg, net, portid, RTNLGRP_NSID, nlh, gfp); 1193 return; 1194 1195 err_out: 1196 nlmsg_free(msg); 1197 out: 1198 rtnl_set_sk_err(net, RTNLGRP_NSID, err); 1199 } 1200 1201 #ifdef CONFIG_NET_NS 1202 static void __init netns_ipv4_struct_check(void) 1203 { 1204 /* TX readonly hotpath cache lines */ 1205 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1206 sysctl_tcp_early_retrans); 1207 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1208 sysctl_tcp_tso_win_divisor); 1209 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1210 sysctl_tcp_tso_rtt_log); 1211 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1212 sysctl_tcp_autocorking); 1213 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1214 sysctl_tcp_min_snd_mss); 1215 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1216 sysctl_tcp_notsent_lowat); 1217 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1218 sysctl_tcp_limit_output_bytes); 1219 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1220 sysctl_tcp_min_rtt_wlen); 1221 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1222 sysctl_tcp_wmem); 1223 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx, 1224 sysctl_ip_fwd_use_pmtu); 1225 CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_tx, 33); 1226 1227 /* TXRX readonly hotpath cache lines */ 1228 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_txrx, 1229 sysctl_tcp_moderate_rcvbuf); 1230 CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_txrx, 1); 1231 1232 /* RX readonly hotpath cache line */ 1233 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx, 1234 sysctl_ip_early_demux); 1235 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx, 1236 sysctl_tcp_early_demux); 1237 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx, 1238 sysctl_tcp_l3mdev_accept); 1239 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx, 1240 sysctl_tcp_reordering); 1241 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx, 1242 sysctl_tcp_rmem); 1243 CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_rx, 22); 1244 } 1245 #endif 1246 1247 static const struct rtnl_msg_handler net_ns_rtnl_msg_handlers[] __initconst = { 1248 {.msgtype = RTM_NEWNSID, .doit = rtnl_net_newid, 1249 .flags = RTNL_FLAG_DOIT_UNLOCKED}, 1250 {.msgtype = RTM_GETNSID, .doit = rtnl_net_getid, 1251 .dumpit = rtnl_net_dumpid, 1252 .flags = RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED}, 1253 }; 1254 1255 void __init net_ns_init(void) 1256 { 1257 struct net_generic *ng; 1258 1259 #ifdef CONFIG_NET_NS 1260 netns_ipv4_struct_check(); 1261 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), 1262 SMP_CACHE_BYTES, 1263 SLAB_PANIC|SLAB_ACCOUNT, NULL); 1264 1265 /* Create workqueue for cleanup */ 1266 netns_wq = create_singlethread_workqueue("netns"); 1267 if (!netns_wq) 1268 panic("Could not create netns workq"); 1269 #endif 1270 1271 ng = net_alloc_generic(); 1272 if (!ng) 1273 panic("Could not allocate generic netns"); 1274 1275 rcu_assign_pointer(init_net.gen, ng); 1276 1277 #ifdef CONFIG_KEYS 1278 init_net.key_domain = &init_net_key_domain; 1279 #endif 1280 /* 1281 * This currently cannot fail as the initial network namespace 1282 * has a static inode number. 1283 */ 1284 if (preinit_net(&init_net, &init_user_ns)) 1285 panic("Could not preinitialize the initial network namespace"); 1286 1287 down_write(&pernet_ops_rwsem); 1288 if (setup_net(&init_net)) 1289 panic("Could not setup the initial network namespace"); 1290 1291 init_net_initialized = true; 1292 up_write(&pernet_ops_rwsem); 1293 1294 if (register_pernet_subsys(&net_ns_ops)) 1295 panic("Could not register network namespace subsystems"); 1296 1297 rtnl_register_many(net_ns_rtnl_msg_handlers); 1298 } 1299 1300 #ifdef CONFIG_NET_NS 1301 static int __register_pernet_operations(struct list_head *list, 1302 struct pernet_operations *ops) 1303 { 1304 LIST_HEAD(net_exit_list); 1305 struct net *net; 1306 int error; 1307 1308 list_add_tail(&ops->list, list); 1309 if (ops->init || ops->id) { 1310 /* We held write locked pernet_ops_rwsem, and parallel 1311 * setup_net() and cleanup_net() are not possible. 1312 */ 1313 for_each_net(net) { 1314 error = ops_init(ops, net); 1315 if (error) 1316 goto out_undo; 1317 list_add_tail(&net->exit_list, &net_exit_list); 1318 } 1319 } 1320 return 0; 1321 1322 out_undo: 1323 /* If I have an error cleanup all namespaces I initialized */ 1324 list_del(&ops->list); 1325 ops_undo_single(ops, &net_exit_list); 1326 return error; 1327 } 1328 1329 static void __unregister_pernet_operations(struct pernet_operations *ops) 1330 { 1331 LIST_HEAD(net_exit_list); 1332 struct net *net; 1333 1334 /* See comment in __register_pernet_operations() */ 1335 for_each_net(net) 1336 list_add_tail(&net->exit_list, &net_exit_list); 1337 1338 list_del(&ops->list); 1339 ops_undo_single(ops, &net_exit_list); 1340 } 1341 1342 #else 1343 1344 static int __register_pernet_operations(struct list_head *list, 1345 struct pernet_operations *ops) 1346 { 1347 if (!init_net_initialized) { 1348 list_add_tail(&ops->list, list); 1349 return 0; 1350 } 1351 1352 return ops_init(ops, &init_net); 1353 } 1354 1355 static void __unregister_pernet_operations(struct pernet_operations *ops) 1356 { 1357 if (!init_net_initialized) { 1358 list_del(&ops->list); 1359 } else { 1360 LIST_HEAD(net_exit_list); 1361 1362 list_add(&init_net.exit_list, &net_exit_list); 1363 ops_undo_single(ops, &net_exit_list); 1364 } 1365 } 1366 1367 #endif /* CONFIG_NET_NS */ 1368 1369 static DEFINE_IDA(net_generic_ids); 1370 1371 static int register_pernet_operations(struct list_head *list, 1372 struct pernet_operations *ops) 1373 { 1374 int error; 1375 1376 if (WARN_ON(!!ops->id ^ !!ops->size)) 1377 return -EINVAL; 1378 1379 if (ops->id) { 1380 error = ida_alloc_min(&net_generic_ids, MIN_PERNET_OPS_ID, 1381 GFP_KERNEL); 1382 if (error < 0) 1383 return error; 1384 *ops->id = error; 1385 /* This does not require READ_ONCE as writers already hold 1386 * pernet_ops_rwsem. But WRITE_ONCE is needed to protect 1387 * net_alloc_generic. 1388 */ 1389 WRITE_ONCE(max_gen_ptrs, max(max_gen_ptrs, *ops->id + 1)); 1390 } 1391 error = __register_pernet_operations(list, ops); 1392 if (error) { 1393 rcu_barrier(); 1394 if (ops->id) 1395 ida_free(&net_generic_ids, *ops->id); 1396 } 1397 1398 return error; 1399 } 1400 1401 static void unregister_pernet_operations(struct pernet_operations *ops) 1402 { 1403 __unregister_pernet_operations(ops); 1404 rcu_barrier(); 1405 if (ops->id) 1406 ida_free(&net_generic_ids, *ops->id); 1407 } 1408 1409 /** 1410 * register_pernet_subsys - register a network namespace subsystem 1411 * @ops: pernet operations structure for the subsystem 1412 * 1413 * Register a subsystem which has init and exit functions 1414 * that are called when network namespaces are created and 1415 * destroyed respectively. 1416 * 1417 * When registered all network namespace init functions are 1418 * called for every existing network namespace. Allowing kernel 1419 * modules to have a race free view of the set of network namespaces. 1420 * 1421 * When a new network namespace is created all of the init 1422 * methods are called in the order in which they were registered. 1423 * 1424 * When a network namespace is destroyed all of the exit methods 1425 * are called in the reverse of the order with which they were 1426 * registered. 1427 */ 1428 int register_pernet_subsys(struct pernet_operations *ops) 1429 { 1430 int error; 1431 down_write(&pernet_ops_rwsem); 1432 error = register_pernet_operations(first_device, ops); 1433 up_write(&pernet_ops_rwsem); 1434 return error; 1435 } 1436 EXPORT_SYMBOL_GPL(register_pernet_subsys); 1437 1438 /** 1439 * unregister_pernet_subsys - unregister a network namespace subsystem 1440 * @ops: pernet operations structure to manipulate 1441 * 1442 * Remove the pernet operations structure from the list to be 1443 * used when network namespaces are created or destroyed. In 1444 * addition run the exit method for all existing network 1445 * namespaces. 1446 */ 1447 void unregister_pernet_subsys(struct pernet_operations *ops) 1448 { 1449 down_write(&pernet_ops_rwsem); 1450 unregister_pernet_operations(ops); 1451 up_write(&pernet_ops_rwsem); 1452 } 1453 EXPORT_SYMBOL_GPL(unregister_pernet_subsys); 1454 1455 /** 1456 * register_pernet_device - register a network namespace device 1457 * @ops: pernet operations structure for the subsystem 1458 * 1459 * Register a device which has init and exit functions 1460 * that are called when network namespaces are created and 1461 * destroyed respectively. 1462 * 1463 * When registered all network namespace init functions are 1464 * called for every existing network namespace. Allowing kernel 1465 * modules to have a race free view of the set of network namespaces. 1466 * 1467 * When a new network namespace is created all of the init 1468 * methods are called in the order in which they were registered. 1469 * 1470 * When a network namespace is destroyed all of the exit methods 1471 * are called in the reverse of the order with which they were 1472 * registered. 1473 */ 1474 int register_pernet_device(struct pernet_operations *ops) 1475 { 1476 int error; 1477 down_write(&pernet_ops_rwsem); 1478 error = register_pernet_operations(&pernet_list, ops); 1479 if (!error && (first_device == &pernet_list)) 1480 first_device = &ops->list; 1481 up_write(&pernet_ops_rwsem); 1482 return error; 1483 } 1484 EXPORT_SYMBOL_GPL(register_pernet_device); 1485 1486 /** 1487 * unregister_pernet_device - unregister a network namespace netdevice 1488 * @ops: pernet operations structure to manipulate 1489 * 1490 * Remove the pernet operations structure from the list to be 1491 * used when network namespaces are created or destroyed. In 1492 * addition run the exit method for all existing network 1493 * namespaces. 1494 */ 1495 void unregister_pernet_device(struct pernet_operations *ops) 1496 { 1497 down_write(&pernet_ops_rwsem); 1498 if (&ops->list == first_device) 1499 first_device = first_device->next; 1500 unregister_pernet_operations(ops); 1501 up_write(&pernet_ops_rwsem); 1502 } 1503 EXPORT_SYMBOL_GPL(unregister_pernet_device); 1504 1505 #ifdef CONFIG_NET_NS 1506 static struct ns_common *netns_get(struct task_struct *task) 1507 { 1508 struct net *net = NULL; 1509 struct nsproxy *nsproxy; 1510 1511 task_lock(task); 1512 nsproxy = task->nsproxy; 1513 if (nsproxy) 1514 net = get_net(nsproxy->net_ns); 1515 task_unlock(task); 1516 1517 return net ? &net->ns : NULL; 1518 } 1519 1520 static void netns_put(struct ns_common *ns) 1521 { 1522 put_net(to_net_ns(ns)); 1523 } 1524 1525 static int netns_install(struct nsset *nsset, struct ns_common *ns) 1526 { 1527 struct nsproxy *nsproxy = nsset->nsproxy; 1528 struct net *net = to_net_ns(ns); 1529 1530 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) || 1531 !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN)) 1532 return -EPERM; 1533 1534 put_net(nsproxy->net_ns); 1535 nsproxy->net_ns = get_net(net); 1536 return 0; 1537 } 1538 1539 static struct user_namespace *netns_owner(struct ns_common *ns) 1540 { 1541 return to_net_ns(ns)->user_ns; 1542 } 1543 1544 const struct proc_ns_operations netns_operations = { 1545 .name = "net", 1546 .get = netns_get, 1547 .put = netns_put, 1548 .install = netns_install, 1549 .owner = netns_owner, 1550 }; 1551 #endif