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/cookie.h> 23 24#include <net/sock.h> 25#include <net/netlink.h> 26#include <net/net_namespace.h> 27#include <net/netns/generic.h> 28 29/* 30 * Our network namespace constructor/destructor lists 31 */ 32 33static LIST_HEAD(pernet_list); 34static struct list_head *first_device = &pernet_list; 35 36LIST_HEAD(net_namespace_list); 37EXPORT_SYMBOL_GPL(net_namespace_list); 38 39/* Protects net_namespace_list. Nests iside rtnl_lock() */ 40DECLARE_RWSEM(net_rwsem); 41EXPORT_SYMBOL_GPL(net_rwsem); 42 43#ifdef CONFIG_KEYS 44static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) }; 45#endif 46 47struct net init_net = { 48 .count = REFCOUNT_INIT(1), 49 .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head), 50#ifdef CONFIG_KEYS 51 .key_domain = &init_net_key_domain, 52#endif 53}; 54EXPORT_SYMBOL(init_net); 55 56static bool init_net_initialized; 57/* 58 * pernet_ops_rwsem: protects: pernet_list, net_generic_ids, 59 * init_net_initialized and first_device pointer. 60 * This is internal net namespace object. Please, don't use it 61 * outside. 62 */ 63DECLARE_RWSEM(pernet_ops_rwsem); 64EXPORT_SYMBOL_GPL(pernet_ops_rwsem); 65 66#define MIN_PERNET_OPS_ID \ 67 ((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *)) 68 69#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */ 70 71static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS; 72 73DEFINE_COOKIE(net_cookie); 74 75u64 __net_gen_cookie(struct net *net) 76{ 77 while (1) { 78 u64 res = atomic64_read(&net->net_cookie); 79 80 if (res) 81 return res; 82 res = gen_cookie_next(&net_cookie); 83 atomic64_cmpxchg(&net->net_cookie, 0, res); 84 } 85} 86 87static struct net_generic *net_alloc_generic(void) 88{ 89 unsigned int gen_ptrs = READ_ONCE(max_gen_ptrs); 90 unsigned int generic_size; 91 struct net_generic *ng; 92 93 generic_size = offsetof(struct net_generic, ptr[gen_ptrs]); 94 95 ng = kzalloc(generic_size, GFP_KERNEL); 96 if (ng) 97 ng->s.len = gen_ptrs; 98 99 return ng; 100} 101 102static int net_assign_generic(struct net *net, unsigned int id, void *data) 103{ 104 struct net_generic *ng, *old_ng; 105 106 BUG_ON(id < MIN_PERNET_OPS_ID); 107 108 old_ng = rcu_dereference_protected(net->gen, 109 lockdep_is_held(&pernet_ops_rwsem)); 110 if (old_ng->s.len > id) { 111 old_ng->ptr[id] = data; 112 return 0; 113 } 114 115 ng = net_alloc_generic(); 116 if (ng == NULL) 117 return -ENOMEM; 118 119 /* 120 * Some synchronisation notes: 121 * 122 * The net_generic explores the net->gen array inside rcu 123 * read section. Besides once set the net->gen->ptr[x] 124 * pointer never changes (see rules in netns/generic.h). 125 * 126 * That said, we simply duplicate this array and schedule 127 * the old copy for kfree after a grace period. 128 */ 129 130 memcpy(&ng->ptr[MIN_PERNET_OPS_ID], &old_ng->ptr[MIN_PERNET_OPS_ID], 131 (old_ng->s.len - MIN_PERNET_OPS_ID) * sizeof(void *)); 132 ng->ptr[id] = data; 133 134 rcu_assign_pointer(net->gen, ng); 135 kfree_rcu(old_ng, s.rcu); 136 return 0; 137} 138 139static int ops_init(const struct pernet_operations *ops, struct net *net) 140{ 141 struct net_generic *ng; 142 int err = -ENOMEM; 143 void *data = NULL; 144 145 if (ops->id && ops->size) { 146 data = kzalloc(ops->size, GFP_KERNEL); 147 if (!data) 148 goto out; 149 150 err = net_assign_generic(net, *ops->id, data); 151 if (err) 152 goto cleanup; 153 } 154 err = 0; 155 if (ops->init) 156 err = ops->init(net); 157 if (!err) 158 return 0; 159 160 if (ops->id && ops->size) { 161 ng = rcu_dereference_protected(net->gen, 162 lockdep_is_held(&pernet_ops_rwsem)); 163 ng->ptr[*ops->id] = NULL; 164 } 165 166cleanup: 167 kfree(data); 168 169out: 170 return err; 171} 172 173static void ops_free(const struct pernet_operations *ops, struct net *net) 174{ 175 if (ops->id && ops->size) { 176 kfree(net_generic(net, *ops->id)); 177 } 178} 179 180static void ops_pre_exit_list(const struct pernet_operations *ops, 181 struct list_head *net_exit_list) 182{ 183 struct net *net; 184 185 if (ops->pre_exit) { 186 list_for_each_entry(net, net_exit_list, exit_list) 187 ops->pre_exit(net); 188 } 189} 190 191static void ops_exit_list(const struct pernet_operations *ops, 192 struct list_head *net_exit_list) 193{ 194 struct net *net; 195 if (ops->exit) { 196 list_for_each_entry(net, net_exit_list, exit_list) { 197 ops->exit(net); 198 cond_resched(); 199 } 200 } 201 if (ops->exit_batch) 202 ops->exit_batch(net_exit_list); 203} 204 205static void ops_free_list(const struct pernet_operations *ops, 206 struct list_head *net_exit_list) 207{ 208 struct net *net; 209 if (ops->size && ops->id) { 210 list_for_each_entry(net, net_exit_list, exit_list) 211 ops_free(ops, net); 212 } 213} 214 215/* should be called with nsid_lock held */ 216static int alloc_netid(struct net *net, struct net *peer, int reqid) 217{ 218 int min = 0, max = 0; 219 220 if (reqid >= 0) { 221 min = reqid; 222 max = reqid + 1; 223 } 224 225 return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC); 226} 227 228/* This function is used by idr_for_each(). If net is equal to peer, the 229 * function returns the id so that idr_for_each() stops. Because we cannot 230 * returns the id 0 (idr_for_each() will not stop), we return the magic value 231 * NET_ID_ZERO (-1) for it. 232 */ 233#define NET_ID_ZERO -1 234static int net_eq_idr(int id, void *net, void *peer) 235{ 236 if (net_eq(net, peer)) 237 return id ? : NET_ID_ZERO; 238 return 0; 239} 240 241/* Must be called from RCU-critical section or with nsid_lock held */ 242static int __peernet2id(const struct net *net, struct net *peer) 243{ 244 int id = idr_for_each(&net->netns_ids, net_eq_idr, peer); 245 246 /* Magic value for id 0. */ 247 if (id == NET_ID_ZERO) 248 return 0; 249 if (id > 0) 250 return id; 251 252 return NETNSA_NSID_NOT_ASSIGNED; 253} 254 255static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, 256 struct nlmsghdr *nlh, gfp_t gfp); 257/* This function returns the id of a peer netns. If no id is assigned, one will 258 * be allocated and returned. 259 */ 260int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp) 261{ 262 int id; 263 264 if (refcount_read(&net->count) == 0) 265 return NETNSA_NSID_NOT_ASSIGNED; 266 267 spin_lock_bh(&net->nsid_lock); 268 id = __peernet2id(net, peer); 269 if (id >= 0) { 270 spin_unlock_bh(&net->nsid_lock); 271 return id; 272 } 273 274 /* When peer is obtained from RCU lists, we may race with 275 * its cleanup. Check whether it's alive, and this guarantees 276 * we never hash a peer back to net->netns_ids, after it has 277 * just been idr_remove()'d from there in cleanup_net(). 278 */ 279 if (!maybe_get_net(peer)) { 280 spin_unlock_bh(&net->nsid_lock); 281 return NETNSA_NSID_NOT_ASSIGNED; 282 } 283 284 id = alloc_netid(net, peer, -1); 285 spin_unlock_bh(&net->nsid_lock); 286 287 put_net(peer); 288 if (id < 0) 289 return NETNSA_NSID_NOT_ASSIGNED; 290 291 rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL, gfp); 292 293 return id; 294} 295EXPORT_SYMBOL_GPL(peernet2id_alloc); 296 297/* This function returns, if assigned, the id of a peer netns. */ 298int peernet2id(const struct net *net, struct net *peer) 299{ 300 int id; 301 302 rcu_read_lock(); 303 id = __peernet2id(net, peer); 304 rcu_read_unlock(); 305 306 return id; 307} 308EXPORT_SYMBOL(peernet2id); 309 310/* This function returns true is the peer netns has an id assigned into the 311 * current netns. 312 */ 313bool peernet_has_id(const struct net *net, struct net *peer) 314{ 315 return peernet2id(net, peer) >= 0; 316} 317 318struct net *get_net_ns_by_id(const struct net *net, int id) 319{ 320 struct net *peer; 321 322 if (id < 0) 323 return NULL; 324 325 rcu_read_lock(); 326 peer = idr_find(&net->netns_ids, id); 327 if (peer) 328 peer = maybe_get_net(peer); 329 rcu_read_unlock(); 330 331 return peer; 332} 333 334/* 335 * setup_net runs the initializers for the network namespace object. 336 */ 337static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) 338{ 339 /* Must be called with pernet_ops_rwsem held */ 340 const struct pernet_operations *ops, *saved_ops; 341 int error = 0; 342 LIST_HEAD(net_exit_list); 343 344 refcount_set(&net->count, 1); 345 refcount_set(&net->passive, 1); 346 get_random_bytes(&net->hash_mix, sizeof(u32)); 347 net->dev_base_seq = 1; 348 net->user_ns = user_ns; 349 idr_init(&net->netns_ids); 350 spin_lock_init(&net->nsid_lock); 351 mutex_init(&net->ipv4.ra_mutex); 352 353 list_for_each_entry(ops, &pernet_list, list) { 354 error = ops_init(ops, net); 355 if (error < 0) 356 goto out_undo; 357 } 358 down_write(&net_rwsem); 359 list_add_tail_rcu(&net->list, &net_namespace_list); 360 up_write(&net_rwsem); 361out: 362 return error; 363 364out_undo: 365 /* Walk through the list backwards calling the exit functions 366 * for the pernet modules whose init functions did not fail. 367 */ 368 list_add(&net->exit_list, &net_exit_list); 369 saved_ops = ops; 370 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 371 ops_pre_exit_list(ops, &net_exit_list); 372 373 synchronize_rcu(); 374 375 ops = saved_ops; 376 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 377 ops_exit_list(ops, &net_exit_list); 378 379 ops = saved_ops; 380 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 381 ops_free_list(ops, &net_exit_list); 382 383 rcu_barrier(); 384 goto out; 385} 386 387static int __net_init net_defaults_init_net(struct net *net) 388{ 389 net->core.sysctl_somaxconn = SOMAXCONN; 390 return 0; 391} 392 393static struct pernet_operations net_defaults_ops = { 394 .init = net_defaults_init_net, 395}; 396 397static __init int net_defaults_init(void) 398{ 399 if (register_pernet_subsys(&net_defaults_ops)) 400 panic("Cannot initialize net default settings"); 401 402 return 0; 403} 404 405core_initcall(net_defaults_init); 406 407#ifdef CONFIG_NET_NS 408static struct ucounts *inc_net_namespaces(struct user_namespace *ns) 409{ 410 return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES); 411} 412 413static void dec_net_namespaces(struct ucounts *ucounts) 414{ 415 dec_ucount(ucounts, UCOUNT_NET_NAMESPACES); 416} 417 418static struct kmem_cache *net_cachep __ro_after_init; 419static struct workqueue_struct *netns_wq; 420 421static struct net *net_alloc(void) 422{ 423 struct net *net = NULL; 424 struct net_generic *ng; 425 426 ng = net_alloc_generic(); 427 if (!ng) 428 goto out; 429 430 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL); 431 if (!net) 432 goto out_free; 433 434#ifdef CONFIG_KEYS 435 net->key_domain = kzalloc(sizeof(struct key_tag), GFP_KERNEL); 436 if (!net->key_domain) 437 goto out_free_2; 438 refcount_set(&net->key_domain->usage, 1); 439#endif 440 441 rcu_assign_pointer(net->gen, ng); 442out: 443 return net; 444 445#ifdef CONFIG_KEYS 446out_free_2: 447 kmem_cache_free(net_cachep, net); 448 net = NULL; 449#endif 450out_free: 451 kfree(ng); 452 goto out; 453} 454 455static void net_free(struct net *net) 456{ 457 kfree(rcu_access_pointer(net->gen)); 458 kmem_cache_free(net_cachep, net); 459} 460 461void net_drop_ns(void *p) 462{ 463 struct net *ns = p; 464 if (ns && refcount_dec_and_test(&ns->passive)) 465 net_free(ns); 466} 467 468struct net *copy_net_ns(unsigned long flags, 469 struct user_namespace *user_ns, struct net *old_net) 470{ 471 struct ucounts *ucounts; 472 struct net *net; 473 int rv; 474 475 if (!(flags & CLONE_NEWNET)) 476 return get_net(old_net); 477 478 ucounts = inc_net_namespaces(user_ns); 479 if (!ucounts) 480 return ERR_PTR(-ENOSPC); 481 482 net = net_alloc(); 483 if (!net) { 484 rv = -ENOMEM; 485 goto dec_ucounts; 486 } 487 refcount_set(&net->passive, 1); 488 net->ucounts = ucounts; 489 get_user_ns(user_ns); 490 491 rv = down_read_killable(&pernet_ops_rwsem); 492 if (rv < 0) 493 goto put_userns; 494 495 rv = setup_net(net, user_ns); 496 497 up_read(&pernet_ops_rwsem); 498 499 if (rv < 0) { 500put_userns: 501#ifdef CONFIG_KEYS 502 key_remove_domain(net->key_domain); 503#endif 504 put_user_ns(user_ns); 505 net_drop_ns(net); 506dec_ucounts: 507 dec_net_namespaces(ucounts); 508 return ERR_PTR(rv); 509 } 510 return net; 511} 512 513/** 514 * net_ns_get_ownership - get sysfs ownership data for @net 515 * @net: network namespace in question (can be NULL) 516 * @uid: kernel user ID for sysfs objects 517 * @gid: kernel group ID for sysfs objects 518 * 519 * Returns the uid/gid pair of root in the user namespace associated with the 520 * given network namespace. 521 */ 522void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid) 523{ 524 if (net) { 525 kuid_t ns_root_uid = make_kuid(net->user_ns, 0); 526 kgid_t ns_root_gid = make_kgid(net->user_ns, 0); 527 528 if (uid_valid(ns_root_uid)) 529 *uid = ns_root_uid; 530 531 if (gid_valid(ns_root_gid)) 532 *gid = ns_root_gid; 533 } else { 534 *uid = GLOBAL_ROOT_UID; 535 *gid = GLOBAL_ROOT_GID; 536 } 537} 538EXPORT_SYMBOL_GPL(net_ns_get_ownership); 539 540static void unhash_nsid(struct net *net, struct net *last) 541{ 542 struct net *tmp; 543 /* This function is only called from cleanup_net() work, 544 * and this work is the only process, that may delete 545 * a net from net_namespace_list. So, when the below 546 * is executing, the list may only grow. Thus, we do not 547 * use for_each_net_rcu() or net_rwsem. 548 */ 549 for_each_net(tmp) { 550 int id; 551 552 spin_lock_bh(&tmp->nsid_lock); 553 id = __peernet2id(tmp, net); 554 if (id >= 0) 555 idr_remove(&tmp->netns_ids, id); 556 spin_unlock_bh(&tmp->nsid_lock); 557 if (id >= 0) 558 rtnl_net_notifyid(tmp, RTM_DELNSID, id, 0, NULL, 559 GFP_KERNEL); 560 if (tmp == last) 561 break; 562 } 563 spin_lock_bh(&net->nsid_lock); 564 idr_destroy(&net->netns_ids); 565 spin_unlock_bh(&net->nsid_lock); 566} 567 568static LLIST_HEAD(cleanup_list); 569 570static void cleanup_net(struct work_struct *work) 571{ 572 const struct pernet_operations *ops; 573 struct net *net, *tmp, *last; 574 struct llist_node *net_kill_list; 575 LIST_HEAD(net_exit_list); 576 577 /* Atomically snapshot the list of namespaces to cleanup */ 578 net_kill_list = llist_del_all(&cleanup_list); 579 580 down_read(&pernet_ops_rwsem); 581 582 /* Don't let anyone else find us. */ 583 down_write(&net_rwsem); 584 llist_for_each_entry(net, net_kill_list, cleanup_list) 585 list_del_rcu(&net->list); 586 /* Cache last net. After we unlock rtnl, no one new net 587 * added to net_namespace_list can assign nsid pointer 588 * to a net from net_kill_list (see peernet2id_alloc()). 589 * So, we skip them in unhash_nsid(). 590 * 591 * Note, that unhash_nsid() does not delete nsid links 592 * between net_kill_list's nets, as they've already 593 * deleted from net_namespace_list. But, this would be 594 * useless anyway, as netns_ids are destroyed there. 595 */ 596 last = list_last_entry(&net_namespace_list, struct net, list); 597 up_write(&net_rwsem); 598 599 llist_for_each_entry(net, net_kill_list, cleanup_list) { 600 unhash_nsid(net, last); 601 list_add_tail(&net->exit_list, &net_exit_list); 602 } 603 604 /* Run all of the network namespace pre_exit methods */ 605 list_for_each_entry_reverse(ops, &pernet_list, list) 606 ops_pre_exit_list(ops, &net_exit_list); 607 608 /* 609 * Another CPU might be rcu-iterating the list, wait for it. 610 * This needs to be before calling the exit() notifiers, so 611 * the rcu_barrier() below isn't sufficient alone. 612 * Also the pre_exit() and exit() methods need this barrier. 613 */ 614 synchronize_rcu(); 615 616 /* Run all of the network namespace exit methods */ 617 list_for_each_entry_reverse(ops, &pernet_list, list) 618 ops_exit_list(ops, &net_exit_list); 619 620 /* Free the net generic variables */ 621 list_for_each_entry_reverse(ops, &pernet_list, list) 622 ops_free_list(ops, &net_exit_list); 623 624 up_read(&pernet_ops_rwsem); 625 626 /* Ensure there are no outstanding rcu callbacks using this 627 * network namespace. 628 */ 629 rcu_barrier(); 630 631 /* Finally it is safe to free my network namespace structure */ 632 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { 633 list_del_init(&net->exit_list); 634 dec_net_namespaces(net->ucounts); 635#ifdef CONFIG_KEYS 636 key_remove_domain(net->key_domain); 637#endif 638 put_user_ns(net->user_ns); 639 net_drop_ns(net); 640 } 641} 642 643/** 644 * net_ns_barrier - wait until concurrent net_cleanup_work is done 645 * 646 * cleanup_net runs from work queue and will first remove namespaces 647 * from the global list, then run net exit functions. 648 * 649 * Call this in module exit path to make sure that all netns 650 * ->exit ops have been invoked before the function is removed. 651 */ 652void net_ns_barrier(void) 653{ 654 down_write(&pernet_ops_rwsem); 655 up_write(&pernet_ops_rwsem); 656} 657EXPORT_SYMBOL(net_ns_barrier); 658 659static DECLARE_WORK(net_cleanup_work, cleanup_net); 660 661void __put_net(struct net *net) 662{ 663 /* Cleanup the network namespace in process context */ 664 if (llist_add(&net->cleanup_list, &cleanup_list)) 665 queue_work(netns_wq, &net_cleanup_work); 666} 667EXPORT_SYMBOL_GPL(__put_net); 668 669/** 670 * get_net_ns - increment the refcount of the network namespace 671 * @ns: common namespace (net) 672 * 673 * Returns the net's common namespace. 674 */ 675struct ns_common *get_net_ns(struct ns_common *ns) 676{ 677 return &get_net(container_of(ns, struct net, ns))->ns; 678} 679EXPORT_SYMBOL_GPL(get_net_ns); 680 681struct net *get_net_ns_by_fd(int fd) 682{ 683 struct file *file; 684 struct ns_common *ns; 685 struct net *net; 686 687 file = proc_ns_fget(fd); 688 if (IS_ERR(file)) 689 return ERR_CAST(file); 690 691 ns = get_proc_ns(file_inode(file)); 692 if (ns->ops == &netns_operations) 693 net = get_net(container_of(ns, struct net, ns)); 694 else 695 net = ERR_PTR(-EINVAL); 696 697 fput(file); 698 return net; 699} 700 701#else 702struct net *get_net_ns_by_fd(int fd) 703{ 704 return ERR_PTR(-EINVAL); 705} 706#endif 707EXPORT_SYMBOL_GPL(get_net_ns_by_fd); 708 709struct net *get_net_ns_by_pid(pid_t pid) 710{ 711 struct task_struct *tsk; 712 struct net *net; 713 714 /* Lookup the network namespace */ 715 net = ERR_PTR(-ESRCH); 716 rcu_read_lock(); 717 tsk = find_task_by_vpid(pid); 718 if (tsk) { 719 struct nsproxy *nsproxy; 720 task_lock(tsk); 721 nsproxy = tsk->nsproxy; 722 if (nsproxy) 723 net = get_net(nsproxy->net_ns); 724 task_unlock(tsk); 725 } 726 rcu_read_unlock(); 727 return net; 728} 729EXPORT_SYMBOL_GPL(get_net_ns_by_pid); 730 731static __net_init int net_ns_net_init(struct net *net) 732{ 733#ifdef CONFIG_NET_NS 734 net->ns.ops = &netns_operations; 735#endif 736 return ns_alloc_inum(&net->ns); 737} 738 739static __net_exit void net_ns_net_exit(struct net *net) 740{ 741 ns_free_inum(&net->ns); 742} 743 744static struct pernet_operations __net_initdata net_ns_ops = { 745 .init = net_ns_net_init, 746 .exit = net_ns_net_exit, 747}; 748 749static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = { 750 [NETNSA_NONE] = { .type = NLA_UNSPEC }, 751 [NETNSA_NSID] = { .type = NLA_S32 }, 752 [NETNSA_PID] = { .type = NLA_U32 }, 753 [NETNSA_FD] = { .type = NLA_U32 }, 754 [NETNSA_TARGET_NSID] = { .type = NLA_S32 }, 755}; 756 757static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh, 758 struct netlink_ext_ack *extack) 759{ 760 struct net *net = sock_net(skb->sk); 761 struct nlattr *tb[NETNSA_MAX + 1]; 762 struct nlattr *nla; 763 struct net *peer; 764 int nsid, err; 765 766 err = nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg), tb, 767 NETNSA_MAX, rtnl_net_policy, extack); 768 if (err < 0) 769 return err; 770 if (!tb[NETNSA_NSID]) { 771 NL_SET_ERR_MSG(extack, "nsid is missing"); 772 return -EINVAL; 773 } 774 nsid = nla_get_s32(tb[NETNSA_NSID]); 775 776 if (tb[NETNSA_PID]) { 777 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 778 nla = tb[NETNSA_PID]; 779 } else if (tb[NETNSA_FD]) { 780 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 781 nla = tb[NETNSA_FD]; 782 } else { 783 NL_SET_ERR_MSG(extack, "Peer netns reference is missing"); 784 return -EINVAL; 785 } 786 if (IS_ERR(peer)) { 787 NL_SET_BAD_ATTR(extack, nla); 788 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid"); 789 return PTR_ERR(peer); 790 } 791 792 spin_lock_bh(&net->nsid_lock); 793 if (__peernet2id(net, peer) >= 0) { 794 spin_unlock_bh(&net->nsid_lock); 795 err = -EEXIST; 796 NL_SET_BAD_ATTR(extack, nla); 797 NL_SET_ERR_MSG(extack, 798 "Peer netns already has a nsid assigned"); 799 goto out; 800 } 801 802 err = alloc_netid(net, peer, nsid); 803 spin_unlock_bh(&net->nsid_lock); 804 if (err >= 0) { 805 rtnl_net_notifyid(net, RTM_NEWNSID, err, NETLINK_CB(skb).portid, 806 nlh, GFP_KERNEL); 807 err = 0; 808 } else if (err == -ENOSPC && nsid >= 0) { 809 err = -EEXIST; 810 NL_SET_BAD_ATTR(extack, tb[NETNSA_NSID]); 811 NL_SET_ERR_MSG(extack, "The specified nsid is already used"); 812 } 813out: 814 put_net(peer); 815 return err; 816} 817 818static int rtnl_net_get_size(void) 819{ 820 return NLMSG_ALIGN(sizeof(struct rtgenmsg)) 821 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */ 822 + nla_total_size(sizeof(s32)) /* NETNSA_CURRENT_NSID */ 823 ; 824} 825 826struct net_fill_args { 827 u32 portid; 828 u32 seq; 829 int flags; 830 int cmd; 831 int nsid; 832 bool add_ref; 833 int ref_nsid; 834}; 835 836static int rtnl_net_fill(struct sk_buff *skb, struct net_fill_args *args) 837{ 838 struct nlmsghdr *nlh; 839 struct rtgenmsg *rth; 840 841 nlh = nlmsg_put(skb, args->portid, args->seq, args->cmd, sizeof(*rth), 842 args->flags); 843 if (!nlh) 844 return -EMSGSIZE; 845 846 rth = nlmsg_data(nlh); 847 rth->rtgen_family = AF_UNSPEC; 848 849 if (nla_put_s32(skb, NETNSA_NSID, args->nsid)) 850 goto nla_put_failure; 851 852 if (args->add_ref && 853 nla_put_s32(skb, NETNSA_CURRENT_NSID, args->ref_nsid)) 854 goto nla_put_failure; 855 856 nlmsg_end(skb, nlh); 857 return 0; 858 859nla_put_failure: 860 nlmsg_cancel(skb, nlh); 861 return -EMSGSIZE; 862} 863 864static int rtnl_net_valid_getid_req(struct sk_buff *skb, 865 const struct nlmsghdr *nlh, 866 struct nlattr **tb, 867 struct netlink_ext_ack *extack) 868{ 869 int i, err; 870 871 if (!netlink_strict_get_check(skb)) 872 return nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg), 873 tb, NETNSA_MAX, rtnl_net_policy, 874 extack); 875 876 err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb, 877 NETNSA_MAX, rtnl_net_policy, 878 extack); 879 if (err) 880 return err; 881 882 for (i = 0; i <= NETNSA_MAX; i++) { 883 if (!tb[i]) 884 continue; 885 886 switch (i) { 887 case NETNSA_PID: 888 case NETNSA_FD: 889 case NETNSA_NSID: 890 case NETNSA_TARGET_NSID: 891 break; 892 default: 893 NL_SET_ERR_MSG(extack, "Unsupported attribute in peer netns getid request"); 894 return -EINVAL; 895 } 896 } 897 898 return 0; 899} 900 901static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh, 902 struct netlink_ext_ack *extack) 903{ 904 struct net *net = sock_net(skb->sk); 905 struct nlattr *tb[NETNSA_MAX + 1]; 906 struct net_fill_args fillargs = { 907 .portid = NETLINK_CB(skb).portid, 908 .seq = nlh->nlmsg_seq, 909 .cmd = RTM_NEWNSID, 910 }; 911 struct net *peer, *target = net; 912 struct nlattr *nla; 913 struct sk_buff *msg; 914 int err; 915 916 err = rtnl_net_valid_getid_req(skb, nlh, tb, extack); 917 if (err < 0) 918 return err; 919 if (tb[NETNSA_PID]) { 920 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 921 nla = tb[NETNSA_PID]; 922 } else if (tb[NETNSA_FD]) { 923 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 924 nla = tb[NETNSA_FD]; 925 } else if (tb[NETNSA_NSID]) { 926 peer = get_net_ns_by_id(net, nla_get_s32(tb[NETNSA_NSID])); 927 if (!peer) 928 peer = ERR_PTR(-ENOENT); 929 nla = tb[NETNSA_NSID]; 930 } else { 931 NL_SET_ERR_MSG(extack, "Peer netns reference is missing"); 932 return -EINVAL; 933 } 934 935 if (IS_ERR(peer)) { 936 NL_SET_BAD_ATTR(extack, nla); 937 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid"); 938 return PTR_ERR(peer); 939 } 940 941 if (tb[NETNSA_TARGET_NSID]) { 942 int id = nla_get_s32(tb[NETNSA_TARGET_NSID]); 943 944 target = rtnl_get_net_ns_capable(NETLINK_CB(skb).sk, id); 945 if (IS_ERR(target)) { 946 NL_SET_BAD_ATTR(extack, tb[NETNSA_TARGET_NSID]); 947 NL_SET_ERR_MSG(extack, 948 "Target netns reference is invalid"); 949 err = PTR_ERR(target); 950 goto out; 951 } 952 fillargs.add_ref = true; 953 fillargs.ref_nsid = peernet2id(net, peer); 954 } 955 956 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 957 if (!msg) { 958 err = -ENOMEM; 959 goto out; 960 } 961 962 fillargs.nsid = peernet2id(target, peer); 963 err = rtnl_net_fill(msg, &fillargs); 964 if (err < 0) 965 goto err_out; 966 967 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid); 968 goto out; 969 970err_out: 971 nlmsg_free(msg); 972out: 973 if (fillargs.add_ref) 974 put_net(target); 975 put_net(peer); 976 return err; 977} 978 979struct rtnl_net_dump_cb { 980 struct net *tgt_net; 981 struct net *ref_net; 982 struct sk_buff *skb; 983 struct net_fill_args fillargs; 984 int idx; 985 int s_idx; 986}; 987 988/* Runs in RCU-critical section. */ 989static int rtnl_net_dumpid_one(int id, void *peer, void *data) 990{ 991 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data; 992 int ret; 993 994 if (net_cb->idx < net_cb->s_idx) 995 goto cont; 996 997 net_cb->fillargs.nsid = id; 998 if (net_cb->fillargs.add_ref) 999 net_cb->fillargs.ref_nsid = __peernet2id(net_cb->ref_net, peer); 1000 ret = rtnl_net_fill(net_cb->skb, &net_cb->fillargs); 1001 if (ret < 0) 1002 return ret; 1003 1004cont: 1005 net_cb->idx++; 1006 return 0; 1007} 1008 1009static int rtnl_valid_dump_net_req(const struct nlmsghdr *nlh, struct sock *sk, 1010 struct rtnl_net_dump_cb *net_cb, 1011 struct netlink_callback *cb) 1012{ 1013 struct netlink_ext_ack *extack = cb->extack; 1014 struct nlattr *tb[NETNSA_MAX + 1]; 1015 int err, i; 1016 1017 err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb, 1018 NETNSA_MAX, rtnl_net_policy, 1019 extack); 1020 if (err < 0) 1021 return err; 1022 1023 for (i = 0; i <= NETNSA_MAX; i++) { 1024 if (!tb[i]) 1025 continue; 1026 1027 if (i == NETNSA_TARGET_NSID) { 1028 struct net *net; 1029 1030 net = rtnl_get_net_ns_capable(sk, nla_get_s32(tb[i])); 1031 if (IS_ERR(net)) { 1032 NL_SET_BAD_ATTR(extack, tb[i]); 1033 NL_SET_ERR_MSG(extack, 1034 "Invalid target network namespace id"); 1035 return PTR_ERR(net); 1036 } 1037 net_cb->fillargs.add_ref = true; 1038 net_cb->ref_net = net_cb->tgt_net; 1039 net_cb->tgt_net = net; 1040 } else { 1041 NL_SET_BAD_ATTR(extack, tb[i]); 1042 NL_SET_ERR_MSG(extack, 1043 "Unsupported attribute in dump request"); 1044 return -EINVAL; 1045 } 1046 } 1047 1048 return 0; 1049} 1050 1051static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb) 1052{ 1053 struct rtnl_net_dump_cb net_cb = { 1054 .tgt_net = sock_net(skb->sk), 1055 .skb = skb, 1056 .fillargs = { 1057 .portid = NETLINK_CB(cb->skb).portid, 1058 .seq = cb->nlh->nlmsg_seq, 1059 .flags = NLM_F_MULTI, 1060 .cmd = RTM_NEWNSID, 1061 }, 1062 .idx = 0, 1063 .s_idx = cb->args[0], 1064 }; 1065 int err = 0; 1066 1067 if (cb->strict_check) { 1068 err = rtnl_valid_dump_net_req(cb->nlh, skb->sk, &net_cb, cb); 1069 if (err < 0) 1070 goto end; 1071 } 1072 1073 rcu_read_lock(); 1074 idr_for_each(&net_cb.tgt_net->netns_ids, rtnl_net_dumpid_one, &net_cb); 1075 rcu_read_unlock(); 1076 1077 cb->args[0] = net_cb.idx; 1078end: 1079 if (net_cb.fillargs.add_ref) 1080 put_net(net_cb.tgt_net); 1081 return err < 0 ? err : skb->len; 1082} 1083 1084static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid, 1085 struct nlmsghdr *nlh, gfp_t gfp) 1086{ 1087 struct net_fill_args fillargs = { 1088 .portid = portid, 1089 .seq = nlh ? nlh->nlmsg_seq : 0, 1090 .cmd = cmd, 1091 .nsid = id, 1092 }; 1093 struct sk_buff *msg; 1094 int err = -ENOMEM; 1095 1096 msg = nlmsg_new(rtnl_net_get_size(), gfp); 1097 if (!msg) 1098 goto out; 1099 1100 err = rtnl_net_fill(msg, &fillargs); 1101 if (err < 0) 1102 goto err_out; 1103 1104 rtnl_notify(msg, net, portid, RTNLGRP_NSID, nlh, gfp); 1105 return; 1106 1107err_out: 1108 nlmsg_free(msg); 1109out: 1110 rtnl_set_sk_err(net, RTNLGRP_NSID, err); 1111} 1112 1113static int __init net_ns_init(void) 1114{ 1115 struct net_generic *ng; 1116 1117#ifdef CONFIG_NET_NS 1118 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), 1119 SMP_CACHE_BYTES, 1120 SLAB_PANIC|SLAB_ACCOUNT, NULL); 1121 1122 /* Create workqueue for cleanup */ 1123 netns_wq = create_singlethread_workqueue("netns"); 1124 if (!netns_wq) 1125 panic("Could not create netns workq"); 1126#endif 1127 1128 ng = net_alloc_generic(); 1129 if (!ng) 1130 panic("Could not allocate generic netns"); 1131 1132 rcu_assign_pointer(init_net.gen, ng); 1133 1134 preempt_disable(); 1135 __net_gen_cookie(&init_net); 1136 preempt_enable(); 1137 1138 down_write(&pernet_ops_rwsem); 1139 if (setup_net(&init_net, &init_user_ns)) 1140 panic("Could not setup the initial network namespace"); 1141 1142 init_net_initialized = true; 1143 up_write(&pernet_ops_rwsem); 1144 1145 if (register_pernet_subsys(&net_ns_ops)) 1146 panic("Could not register network namespace subsystems"); 1147 1148 rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, 1149 RTNL_FLAG_DOIT_UNLOCKED); 1150 rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid, 1151 RTNL_FLAG_DOIT_UNLOCKED); 1152 1153 return 0; 1154} 1155 1156pure_initcall(net_ns_init); 1157 1158#ifdef CONFIG_NET_NS 1159static int __register_pernet_operations(struct list_head *list, 1160 struct pernet_operations *ops) 1161{ 1162 struct net *net; 1163 int error; 1164 LIST_HEAD(net_exit_list); 1165 1166 list_add_tail(&ops->list, list); 1167 if (ops->init || (ops->id && ops->size)) { 1168 /* We held write locked pernet_ops_rwsem, and parallel 1169 * setup_net() and cleanup_net() are not possible. 1170 */ 1171 for_each_net(net) { 1172 error = ops_init(ops, net); 1173 if (error) 1174 goto out_undo; 1175 list_add_tail(&net->exit_list, &net_exit_list); 1176 } 1177 } 1178 return 0; 1179 1180out_undo: 1181 /* If I have an error cleanup all namespaces I initialized */ 1182 list_del(&ops->list); 1183 ops_pre_exit_list(ops, &net_exit_list); 1184 synchronize_rcu(); 1185 ops_exit_list(ops, &net_exit_list); 1186 ops_free_list(ops, &net_exit_list); 1187 return error; 1188} 1189 1190static void __unregister_pernet_operations(struct pernet_operations *ops) 1191{ 1192 struct net *net; 1193 LIST_HEAD(net_exit_list); 1194 1195 list_del(&ops->list); 1196 /* See comment in __register_pernet_operations() */ 1197 for_each_net(net) 1198 list_add_tail(&net->exit_list, &net_exit_list); 1199 ops_pre_exit_list(ops, &net_exit_list); 1200 synchronize_rcu(); 1201 ops_exit_list(ops, &net_exit_list); 1202 ops_free_list(ops, &net_exit_list); 1203} 1204 1205#else 1206 1207static int __register_pernet_operations(struct list_head *list, 1208 struct pernet_operations *ops) 1209{ 1210 if (!init_net_initialized) { 1211 list_add_tail(&ops->list, list); 1212 return 0; 1213 } 1214 1215 return ops_init(ops, &init_net); 1216} 1217 1218static void __unregister_pernet_operations(struct pernet_operations *ops) 1219{ 1220 if (!init_net_initialized) { 1221 list_del(&ops->list); 1222 } else { 1223 LIST_HEAD(net_exit_list); 1224 list_add(&init_net.exit_list, &net_exit_list); 1225 ops_pre_exit_list(ops, &net_exit_list); 1226 synchronize_rcu(); 1227 ops_exit_list(ops, &net_exit_list); 1228 ops_free_list(ops, &net_exit_list); 1229 } 1230} 1231 1232#endif /* CONFIG_NET_NS */ 1233 1234static DEFINE_IDA(net_generic_ids); 1235 1236static int register_pernet_operations(struct list_head *list, 1237 struct pernet_operations *ops) 1238{ 1239 int error; 1240 1241 if (ops->id) { 1242 error = ida_alloc_min(&net_generic_ids, MIN_PERNET_OPS_ID, 1243 GFP_KERNEL); 1244 if (error < 0) 1245 return error; 1246 *ops->id = error; 1247 /* This does not require READ_ONCE as writers already hold 1248 * pernet_ops_rwsem. But WRITE_ONCE is needed to protect 1249 * net_alloc_generic. 1250 */ 1251 WRITE_ONCE(max_gen_ptrs, max(max_gen_ptrs, *ops->id + 1)); 1252 } 1253 error = __register_pernet_operations(list, ops); 1254 if (error) { 1255 rcu_barrier(); 1256 if (ops->id) 1257 ida_free(&net_generic_ids, *ops->id); 1258 } 1259 1260 return error; 1261} 1262 1263static void unregister_pernet_operations(struct pernet_operations *ops) 1264{ 1265 __unregister_pernet_operations(ops); 1266 rcu_barrier(); 1267 if (ops->id) 1268 ida_free(&net_generic_ids, *ops->id); 1269} 1270 1271/** 1272 * register_pernet_subsys - register a network namespace subsystem 1273 * @ops: pernet operations structure for the subsystem 1274 * 1275 * Register a subsystem which has init and exit functions 1276 * that are called when network namespaces are created and 1277 * destroyed respectively. 1278 * 1279 * When registered all network namespace init functions are 1280 * called for every existing network namespace. Allowing kernel 1281 * modules to have a race free view of the set of network namespaces. 1282 * 1283 * When a new network namespace is created all of the init 1284 * methods are called in the order in which they were registered. 1285 * 1286 * When a network namespace is destroyed all of the exit methods 1287 * are called in the reverse of the order with which they were 1288 * registered. 1289 */ 1290int register_pernet_subsys(struct pernet_operations *ops) 1291{ 1292 int error; 1293 down_write(&pernet_ops_rwsem); 1294 error = register_pernet_operations(first_device, ops); 1295 up_write(&pernet_ops_rwsem); 1296 return error; 1297} 1298EXPORT_SYMBOL_GPL(register_pernet_subsys); 1299 1300/** 1301 * unregister_pernet_subsys - unregister a network namespace subsystem 1302 * @ops: pernet operations structure to manipulate 1303 * 1304 * Remove the pernet operations structure from the list to be 1305 * used when network namespaces are created or destroyed. In 1306 * addition run the exit method for all existing network 1307 * namespaces. 1308 */ 1309void unregister_pernet_subsys(struct pernet_operations *ops) 1310{ 1311 down_write(&pernet_ops_rwsem); 1312 unregister_pernet_operations(ops); 1313 up_write(&pernet_ops_rwsem); 1314} 1315EXPORT_SYMBOL_GPL(unregister_pernet_subsys); 1316 1317/** 1318 * register_pernet_device - register a network namespace device 1319 * @ops: pernet operations structure for the subsystem 1320 * 1321 * Register a device which has init and exit functions 1322 * that are called when network namespaces are created and 1323 * destroyed respectively. 1324 * 1325 * When registered all network namespace init functions are 1326 * called for every existing network namespace. Allowing kernel 1327 * modules to have a race free view of the set of network namespaces. 1328 * 1329 * When a new network namespace is created all of the init 1330 * methods are called in the order in which they were registered. 1331 * 1332 * When a network namespace is destroyed all of the exit methods 1333 * are called in the reverse of the order with which they were 1334 * registered. 1335 */ 1336int register_pernet_device(struct pernet_operations *ops) 1337{ 1338 int error; 1339 down_write(&pernet_ops_rwsem); 1340 error = register_pernet_operations(&pernet_list, ops); 1341 if (!error && (first_device == &pernet_list)) 1342 first_device = &ops->list; 1343 up_write(&pernet_ops_rwsem); 1344 return error; 1345} 1346EXPORT_SYMBOL_GPL(register_pernet_device); 1347 1348/** 1349 * unregister_pernet_device - unregister a network namespace netdevice 1350 * @ops: pernet operations structure to manipulate 1351 * 1352 * Remove the pernet operations structure from the list to be 1353 * used when network namespaces are created or destroyed. In 1354 * addition run the exit method for all existing network 1355 * namespaces. 1356 */ 1357void unregister_pernet_device(struct pernet_operations *ops) 1358{ 1359 down_write(&pernet_ops_rwsem); 1360 if (&ops->list == first_device) 1361 first_device = first_device->next; 1362 unregister_pernet_operations(ops); 1363 up_write(&pernet_ops_rwsem); 1364} 1365EXPORT_SYMBOL_GPL(unregister_pernet_device); 1366 1367#ifdef CONFIG_NET_NS 1368static struct ns_common *netns_get(struct task_struct *task) 1369{ 1370 struct net *net = NULL; 1371 struct nsproxy *nsproxy; 1372 1373 task_lock(task); 1374 nsproxy = task->nsproxy; 1375 if (nsproxy) 1376 net = get_net(nsproxy->net_ns); 1377 task_unlock(task); 1378 1379 return net ? &net->ns : NULL; 1380} 1381 1382static inline struct net *to_net_ns(struct ns_common *ns) 1383{ 1384 return container_of(ns, struct net, ns); 1385} 1386 1387static void netns_put(struct ns_common *ns) 1388{ 1389 put_net(to_net_ns(ns)); 1390} 1391 1392static int netns_install(struct nsset *nsset, struct ns_common *ns) 1393{ 1394 struct nsproxy *nsproxy = nsset->nsproxy; 1395 struct net *net = to_net_ns(ns); 1396 1397 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) || 1398 !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN)) 1399 return -EPERM; 1400 1401 put_net(nsproxy->net_ns); 1402 nsproxy->net_ns = get_net(net); 1403 return 0; 1404} 1405 1406static struct user_namespace *netns_owner(struct ns_common *ns) 1407{ 1408 return to_net_ns(ns)->user_ns; 1409} 1410 1411const struct proc_ns_operations netns_operations = { 1412 .name = "net", 1413 .type = CLONE_NEWNET, 1414 .get = netns_get, 1415 .put = netns_put, 1416 .install = netns_install, 1417 .owner = netns_owner, 1418}; 1419#endif 1420