1 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 2 3 #include <linux/workqueue.h> 4 #include <linux/rtnetlink.h> 5 #include <linux/cache.h> 6 #include <linux/slab.h> 7 #include <linux/list.h> 8 #include <linux/delay.h> 9 #include <linux/sched.h> 10 #include <linux/idr.h> 11 #include <linux/rculist.h> 12 #include <linux/nsproxy.h> 13 #include <linux/fs.h> 14 #include <linux/proc_ns.h> 15 #include <linux/file.h> 16 #include <linux/export.h> 17 #include <linux/user_namespace.h> 18 #include <linux/net_namespace.h> 19 #include <net/sock.h> 20 #include <net/netlink.h> 21 #include <net/net_namespace.h> 22 #include <net/netns/generic.h> 23 24 /* 25 * Our network namespace constructor/destructor lists 26 */ 27 28 static LIST_HEAD(pernet_list); 29 static struct list_head *first_device = &pernet_list; 30 DEFINE_MUTEX(net_mutex); 31 32 LIST_HEAD(net_namespace_list); 33 EXPORT_SYMBOL_GPL(net_namespace_list); 34 35 struct net init_net = { 36 .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head), 37 }; 38 EXPORT_SYMBOL(init_net); 39 40 static bool init_net_initialized; 41 42 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */ 43 44 static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS; 45 46 static struct net_generic *net_alloc_generic(void) 47 { 48 struct net_generic *ng; 49 size_t generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]); 50 51 ng = kzalloc(generic_size, GFP_KERNEL); 52 if (ng) 53 ng->len = max_gen_ptrs; 54 55 return ng; 56 } 57 58 static int net_assign_generic(struct net *net, int id, void *data) 59 { 60 struct net_generic *ng, *old_ng; 61 62 BUG_ON(!mutex_is_locked(&net_mutex)); 63 BUG_ON(id == 0); 64 65 old_ng = rcu_dereference_protected(net->gen, 66 lockdep_is_held(&net_mutex)); 67 ng = old_ng; 68 if (old_ng->len >= id) 69 goto assign; 70 71 ng = net_alloc_generic(); 72 if (ng == NULL) 73 return -ENOMEM; 74 75 /* 76 * Some synchronisation notes: 77 * 78 * The net_generic explores the net->gen array inside rcu 79 * read section. Besides once set the net->gen->ptr[x] 80 * pointer never changes (see rules in netns/generic.h). 81 * 82 * That said, we simply duplicate this array and schedule 83 * the old copy for kfree after a grace period. 84 */ 85 86 memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*)); 87 88 rcu_assign_pointer(net->gen, ng); 89 kfree_rcu(old_ng, rcu); 90 assign: 91 ng->ptr[id - 1] = data; 92 return 0; 93 } 94 95 static int ops_init(const struct pernet_operations *ops, struct net *net) 96 { 97 int err = -ENOMEM; 98 void *data = NULL; 99 100 if (ops->id && ops->size) { 101 data = kzalloc(ops->size, GFP_KERNEL); 102 if (!data) 103 goto out; 104 105 err = net_assign_generic(net, *ops->id, data); 106 if (err) 107 goto cleanup; 108 } 109 err = 0; 110 if (ops->init) 111 err = ops->init(net); 112 if (!err) 113 return 0; 114 115 cleanup: 116 kfree(data); 117 118 out: 119 return err; 120 } 121 122 static void ops_free(const struct pernet_operations *ops, struct net *net) 123 { 124 if (ops->id && ops->size) { 125 int id = *ops->id; 126 kfree(net_generic(net, id)); 127 } 128 } 129 130 static void ops_exit_list(const struct pernet_operations *ops, 131 struct list_head *net_exit_list) 132 { 133 struct net *net; 134 if (ops->exit) { 135 list_for_each_entry(net, net_exit_list, exit_list) 136 ops->exit(net); 137 } 138 if (ops->exit_batch) 139 ops->exit_batch(net_exit_list); 140 } 141 142 static void ops_free_list(const struct pernet_operations *ops, 143 struct list_head *net_exit_list) 144 { 145 struct net *net; 146 if (ops->size && ops->id) { 147 list_for_each_entry(net, net_exit_list, exit_list) 148 ops_free(ops, net); 149 } 150 } 151 152 /* should be called with nsid_lock held */ 153 static int alloc_netid(struct net *net, struct net *peer, int reqid) 154 { 155 int min = 0, max = 0; 156 157 if (reqid >= 0) { 158 min = reqid; 159 max = reqid + 1; 160 } 161 162 return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC); 163 } 164 165 /* This function is used by idr_for_each(). If net is equal to peer, the 166 * function returns the id so that idr_for_each() stops. Because we cannot 167 * returns the id 0 (idr_for_each() will not stop), we return the magic value 168 * NET_ID_ZERO (-1) for it. 169 */ 170 #define NET_ID_ZERO -1 171 static int net_eq_idr(int id, void *net, void *peer) 172 { 173 if (net_eq(net, peer)) 174 return id ? : NET_ID_ZERO; 175 return 0; 176 } 177 178 /* Should be called with nsid_lock held. If a new id is assigned, the bool alloc 179 * is set to true, thus the caller knows that the new id must be notified via 180 * rtnl. 181 */ 182 static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc) 183 { 184 int id = idr_for_each(&net->netns_ids, net_eq_idr, peer); 185 bool alloc_it = *alloc; 186 187 *alloc = false; 188 189 /* Magic value for id 0. */ 190 if (id == NET_ID_ZERO) 191 return 0; 192 if (id > 0) 193 return id; 194 195 if (alloc_it) { 196 id = alloc_netid(net, peer, -1); 197 *alloc = true; 198 return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED; 199 } 200 201 return NETNSA_NSID_NOT_ASSIGNED; 202 } 203 204 /* should be called with nsid_lock held */ 205 static int __peernet2id(struct net *net, struct net *peer) 206 { 207 bool no = false; 208 209 return __peernet2id_alloc(net, peer, &no); 210 } 211 212 static void rtnl_net_notifyid(struct net *net, int cmd, int id); 213 /* This function returns the id of a peer netns. If no id is assigned, one will 214 * be allocated and returned. 215 */ 216 int peernet2id_alloc(struct net *net, struct net *peer) 217 { 218 bool alloc; 219 int id; 220 221 spin_lock_bh(&net->nsid_lock); 222 alloc = atomic_read(&peer->count) == 0 ? false : true; 223 id = __peernet2id_alloc(net, peer, &alloc); 224 spin_unlock_bh(&net->nsid_lock); 225 if (alloc && id >= 0) 226 rtnl_net_notifyid(net, RTM_NEWNSID, id); 227 return id; 228 } 229 230 /* This function returns, if assigned, the id of a peer netns. */ 231 int peernet2id(struct net *net, struct net *peer) 232 { 233 int id; 234 235 spin_lock_bh(&net->nsid_lock); 236 id = __peernet2id(net, peer); 237 spin_unlock_bh(&net->nsid_lock); 238 return id; 239 } 240 EXPORT_SYMBOL(peernet2id); 241 242 /* This function returns true is the peer netns has an id assigned into the 243 * current netns. 244 */ 245 bool peernet_has_id(struct net *net, struct net *peer) 246 { 247 return peernet2id(net, peer) >= 0; 248 } 249 250 struct net *get_net_ns_by_id(struct net *net, int id) 251 { 252 struct net *peer; 253 254 if (id < 0) 255 return NULL; 256 257 rcu_read_lock(); 258 spin_lock_bh(&net->nsid_lock); 259 peer = idr_find(&net->netns_ids, id); 260 if (peer) 261 get_net(peer); 262 spin_unlock_bh(&net->nsid_lock); 263 rcu_read_unlock(); 264 265 return peer; 266 } 267 268 /* 269 * setup_net runs the initializers for the network namespace object. 270 */ 271 static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) 272 { 273 /* Must be called with net_mutex held */ 274 const struct pernet_operations *ops, *saved_ops; 275 int error = 0; 276 LIST_HEAD(net_exit_list); 277 278 atomic_set(&net->count, 1); 279 atomic_set(&net->passive, 1); 280 net->dev_base_seq = 1; 281 net->user_ns = user_ns; 282 idr_init(&net->netns_ids); 283 spin_lock_init(&net->nsid_lock); 284 285 list_for_each_entry(ops, &pernet_list, list) { 286 error = ops_init(ops, net); 287 if (error < 0) 288 goto out_undo; 289 } 290 out: 291 return error; 292 293 out_undo: 294 /* Walk through the list backwards calling the exit functions 295 * for the pernet modules whose init functions did not fail. 296 */ 297 list_add(&net->exit_list, &net_exit_list); 298 saved_ops = ops; 299 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 300 ops_exit_list(ops, &net_exit_list); 301 302 ops = saved_ops; 303 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 304 ops_free_list(ops, &net_exit_list); 305 306 rcu_barrier(); 307 goto out; 308 } 309 310 311 #ifdef CONFIG_NET_NS 312 static struct ucounts *inc_net_namespaces(struct user_namespace *ns) 313 { 314 return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES); 315 } 316 317 static void dec_net_namespaces(struct ucounts *ucounts) 318 { 319 dec_ucount(ucounts, UCOUNT_NET_NAMESPACES); 320 } 321 322 static struct kmem_cache *net_cachep; 323 static struct workqueue_struct *netns_wq; 324 325 static struct net *net_alloc(void) 326 { 327 struct net *net = NULL; 328 struct net_generic *ng; 329 330 ng = net_alloc_generic(); 331 if (!ng) 332 goto out; 333 334 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL); 335 if (!net) 336 goto out_free; 337 338 rcu_assign_pointer(net->gen, ng); 339 out: 340 return net; 341 342 out_free: 343 kfree(ng); 344 goto out; 345 } 346 347 static void net_free(struct net *net) 348 { 349 kfree(rcu_access_pointer(net->gen)); 350 kmem_cache_free(net_cachep, net); 351 } 352 353 void net_drop_ns(void *p) 354 { 355 struct net *ns = p; 356 if (ns && atomic_dec_and_test(&ns->passive)) 357 net_free(ns); 358 } 359 360 struct net *copy_net_ns(unsigned long flags, 361 struct user_namespace *user_ns, struct net *old_net) 362 { 363 struct ucounts *ucounts; 364 struct net *net; 365 int rv; 366 367 if (!(flags & CLONE_NEWNET)) 368 return get_net(old_net); 369 370 ucounts = inc_net_namespaces(user_ns); 371 if (!ucounts) 372 return ERR_PTR(-ENOSPC); 373 374 net = net_alloc(); 375 if (!net) { 376 dec_net_namespaces(ucounts); 377 return ERR_PTR(-ENOMEM); 378 } 379 380 get_user_ns(user_ns); 381 382 mutex_lock(&net_mutex); 383 net->ucounts = ucounts; 384 rv = setup_net(net, user_ns); 385 if (rv == 0) { 386 rtnl_lock(); 387 list_add_tail_rcu(&net->list, &net_namespace_list); 388 rtnl_unlock(); 389 } 390 mutex_unlock(&net_mutex); 391 if (rv < 0) { 392 dec_net_namespaces(ucounts); 393 put_user_ns(user_ns); 394 net_drop_ns(net); 395 return ERR_PTR(rv); 396 } 397 return net; 398 } 399 400 static DEFINE_SPINLOCK(cleanup_list_lock); 401 static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */ 402 403 static void cleanup_net(struct work_struct *work) 404 { 405 const struct pernet_operations *ops; 406 struct net *net, *tmp; 407 struct list_head net_kill_list; 408 LIST_HEAD(net_exit_list); 409 410 /* Atomically snapshot the list of namespaces to cleanup */ 411 spin_lock_irq(&cleanup_list_lock); 412 list_replace_init(&cleanup_list, &net_kill_list); 413 spin_unlock_irq(&cleanup_list_lock); 414 415 mutex_lock(&net_mutex); 416 417 /* Don't let anyone else find us. */ 418 rtnl_lock(); 419 list_for_each_entry(net, &net_kill_list, cleanup_list) { 420 list_del_rcu(&net->list); 421 list_add_tail(&net->exit_list, &net_exit_list); 422 for_each_net(tmp) { 423 int id; 424 425 spin_lock_bh(&tmp->nsid_lock); 426 id = __peernet2id(tmp, net); 427 if (id >= 0) 428 idr_remove(&tmp->netns_ids, id); 429 spin_unlock_bh(&tmp->nsid_lock); 430 if (id >= 0) 431 rtnl_net_notifyid(tmp, RTM_DELNSID, id); 432 } 433 spin_lock_bh(&net->nsid_lock); 434 idr_destroy(&net->netns_ids); 435 spin_unlock_bh(&net->nsid_lock); 436 437 } 438 rtnl_unlock(); 439 440 /* 441 * Another CPU might be rcu-iterating the list, wait for it. 442 * This needs to be before calling the exit() notifiers, so 443 * the rcu_barrier() below isn't sufficient alone. 444 */ 445 synchronize_rcu(); 446 447 /* Run all of the network namespace exit methods */ 448 list_for_each_entry_reverse(ops, &pernet_list, list) 449 ops_exit_list(ops, &net_exit_list); 450 451 /* Free the net generic variables */ 452 list_for_each_entry_reverse(ops, &pernet_list, list) 453 ops_free_list(ops, &net_exit_list); 454 455 mutex_unlock(&net_mutex); 456 457 /* Ensure there are no outstanding rcu callbacks using this 458 * network namespace. 459 */ 460 rcu_barrier(); 461 462 /* Finally it is safe to free my network namespace structure */ 463 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { 464 list_del_init(&net->exit_list); 465 dec_net_namespaces(net->ucounts); 466 put_user_ns(net->user_ns); 467 net_drop_ns(net); 468 } 469 } 470 static DECLARE_WORK(net_cleanup_work, cleanup_net); 471 472 void __put_net(struct net *net) 473 { 474 /* Cleanup the network namespace in process context */ 475 unsigned long flags; 476 477 spin_lock_irqsave(&cleanup_list_lock, flags); 478 list_add(&net->cleanup_list, &cleanup_list); 479 spin_unlock_irqrestore(&cleanup_list_lock, flags); 480 481 queue_work(netns_wq, &net_cleanup_work); 482 } 483 EXPORT_SYMBOL_GPL(__put_net); 484 485 struct net *get_net_ns_by_fd(int fd) 486 { 487 struct file *file; 488 struct ns_common *ns; 489 struct net *net; 490 491 file = proc_ns_fget(fd); 492 if (IS_ERR(file)) 493 return ERR_CAST(file); 494 495 ns = get_proc_ns(file_inode(file)); 496 if (ns->ops == &netns_operations) 497 net = get_net(container_of(ns, struct net, ns)); 498 else 499 net = ERR_PTR(-EINVAL); 500 501 fput(file); 502 return net; 503 } 504 505 #else 506 struct net *get_net_ns_by_fd(int fd) 507 { 508 return ERR_PTR(-EINVAL); 509 } 510 #endif 511 EXPORT_SYMBOL_GPL(get_net_ns_by_fd); 512 513 struct net *get_net_ns_by_pid(pid_t pid) 514 { 515 struct task_struct *tsk; 516 struct net *net; 517 518 /* Lookup the network namespace */ 519 net = ERR_PTR(-ESRCH); 520 rcu_read_lock(); 521 tsk = find_task_by_vpid(pid); 522 if (tsk) { 523 struct nsproxy *nsproxy; 524 task_lock(tsk); 525 nsproxy = tsk->nsproxy; 526 if (nsproxy) 527 net = get_net(nsproxy->net_ns); 528 task_unlock(tsk); 529 } 530 rcu_read_unlock(); 531 return net; 532 } 533 EXPORT_SYMBOL_GPL(get_net_ns_by_pid); 534 535 static __net_init int net_ns_net_init(struct net *net) 536 { 537 #ifdef CONFIG_NET_NS 538 net->ns.ops = &netns_operations; 539 #endif 540 return ns_alloc_inum(&net->ns); 541 } 542 543 static __net_exit void net_ns_net_exit(struct net *net) 544 { 545 ns_free_inum(&net->ns); 546 } 547 548 static struct pernet_operations __net_initdata net_ns_ops = { 549 .init = net_ns_net_init, 550 .exit = net_ns_net_exit, 551 }; 552 553 static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = { 554 [NETNSA_NONE] = { .type = NLA_UNSPEC }, 555 [NETNSA_NSID] = { .type = NLA_S32 }, 556 [NETNSA_PID] = { .type = NLA_U32 }, 557 [NETNSA_FD] = { .type = NLA_U32 }, 558 }; 559 560 static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh) 561 { 562 struct net *net = sock_net(skb->sk); 563 struct nlattr *tb[NETNSA_MAX + 1]; 564 struct net *peer; 565 int nsid, err; 566 567 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, 568 rtnl_net_policy); 569 if (err < 0) 570 return err; 571 if (!tb[NETNSA_NSID]) 572 return -EINVAL; 573 nsid = nla_get_s32(tb[NETNSA_NSID]); 574 575 if (tb[NETNSA_PID]) 576 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 577 else if (tb[NETNSA_FD]) 578 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 579 else 580 return -EINVAL; 581 if (IS_ERR(peer)) 582 return PTR_ERR(peer); 583 584 spin_lock_bh(&net->nsid_lock); 585 if (__peernet2id(net, peer) >= 0) { 586 spin_unlock_bh(&net->nsid_lock); 587 err = -EEXIST; 588 goto out; 589 } 590 591 err = alloc_netid(net, peer, nsid); 592 spin_unlock_bh(&net->nsid_lock); 593 if (err >= 0) { 594 rtnl_net_notifyid(net, RTM_NEWNSID, err); 595 err = 0; 596 } 597 out: 598 put_net(peer); 599 return err; 600 } 601 602 static int rtnl_net_get_size(void) 603 { 604 return NLMSG_ALIGN(sizeof(struct rtgenmsg)) 605 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */ 606 ; 607 } 608 609 static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags, 610 int cmd, struct net *net, int nsid) 611 { 612 struct nlmsghdr *nlh; 613 struct rtgenmsg *rth; 614 615 nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rth), flags); 616 if (!nlh) 617 return -EMSGSIZE; 618 619 rth = nlmsg_data(nlh); 620 rth->rtgen_family = AF_UNSPEC; 621 622 if (nla_put_s32(skb, NETNSA_NSID, nsid)) 623 goto nla_put_failure; 624 625 nlmsg_end(skb, nlh); 626 return 0; 627 628 nla_put_failure: 629 nlmsg_cancel(skb, nlh); 630 return -EMSGSIZE; 631 } 632 633 static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh) 634 { 635 struct net *net = sock_net(skb->sk); 636 struct nlattr *tb[NETNSA_MAX + 1]; 637 struct sk_buff *msg; 638 struct net *peer; 639 int err, id; 640 641 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, 642 rtnl_net_policy); 643 if (err < 0) 644 return err; 645 if (tb[NETNSA_PID]) 646 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 647 else if (tb[NETNSA_FD]) 648 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 649 else 650 return -EINVAL; 651 652 if (IS_ERR(peer)) 653 return PTR_ERR(peer); 654 655 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 656 if (!msg) { 657 err = -ENOMEM; 658 goto out; 659 } 660 661 id = peernet2id(net, peer); 662 err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0, 663 RTM_NEWNSID, net, id); 664 if (err < 0) 665 goto err_out; 666 667 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid); 668 goto out; 669 670 err_out: 671 nlmsg_free(msg); 672 out: 673 put_net(peer); 674 return err; 675 } 676 677 struct rtnl_net_dump_cb { 678 struct net *net; 679 struct sk_buff *skb; 680 struct netlink_callback *cb; 681 int idx; 682 int s_idx; 683 }; 684 685 static int rtnl_net_dumpid_one(int id, void *peer, void *data) 686 { 687 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data; 688 int ret; 689 690 if (net_cb->idx < net_cb->s_idx) 691 goto cont; 692 693 ret = rtnl_net_fill(net_cb->skb, NETLINK_CB(net_cb->cb->skb).portid, 694 net_cb->cb->nlh->nlmsg_seq, NLM_F_MULTI, 695 RTM_NEWNSID, net_cb->net, id); 696 if (ret < 0) 697 return ret; 698 699 cont: 700 net_cb->idx++; 701 return 0; 702 } 703 704 static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb) 705 { 706 struct net *net = sock_net(skb->sk); 707 struct rtnl_net_dump_cb net_cb = { 708 .net = net, 709 .skb = skb, 710 .cb = cb, 711 .idx = 0, 712 .s_idx = cb->args[0], 713 }; 714 715 spin_lock_bh(&net->nsid_lock); 716 idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb); 717 spin_unlock_bh(&net->nsid_lock); 718 719 cb->args[0] = net_cb.idx; 720 return skb->len; 721 } 722 723 static void rtnl_net_notifyid(struct net *net, int cmd, int id) 724 { 725 struct sk_buff *msg; 726 int err = -ENOMEM; 727 728 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 729 if (!msg) 730 goto out; 731 732 err = rtnl_net_fill(msg, 0, 0, 0, cmd, net, id); 733 if (err < 0) 734 goto err_out; 735 736 rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0); 737 return; 738 739 err_out: 740 nlmsg_free(msg); 741 out: 742 rtnl_set_sk_err(net, RTNLGRP_NSID, err); 743 } 744 745 static int __init net_ns_init(void) 746 { 747 struct net_generic *ng; 748 749 #ifdef CONFIG_NET_NS 750 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), 751 SMP_CACHE_BYTES, 752 SLAB_PANIC, NULL); 753 754 /* Create workqueue for cleanup */ 755 netns_wq = create_singlethread_workqueue("netns"); 756 if (!netns_wq) 757 panic("Could not create netns workq"); 758 #endif 759 760 ng = net_alloc_generic(); 761 if (!ng) 762 panic("Could not allocate generic netns"); 763 764 rcu_assign_pointer(init_net.gen, ng); 765 766 mutex_lock(&net_mutex); 767 if (setup_net(&init_net, &init_user_ns)) 768 panic("Could not setup the initial network namespace"); 769 770 init_net_initialized = true; 771 772 rtnl_lock(); 773 list_add_tail_rcu(&init_net.list, &net_namespace_list); 774 rtnl_unlock(); 775 776 mutex_unlock(&net_mutex); 777 778 register_pernet_subsys(&net_ns_ops); 779 780 rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, NULL); 781 rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid, 782 NULL); 783 784 return 0; 785 } 786 787 pure_initcall(net_ns_init); 788 789 #ifdef CONFIG_NET_NS 790 static int __register_pernet_operations(struct list_head *list, 791 struct pernet_operations *ops) 792 { 793 struct net *net; 794 int error; 795 LIST_HEAD(net_exit_list); 796 797 list_add_tail(&ops->list, list); 798 if (ops->init || (ops->id && ops->size)) { 799 for_each_net(net) { 800 error = ops_init(ops, net); 801 if (error) 802 goto out_undo; 803 list_add_tail(&net->exit_list, &net_exit_list); 804 } 805 } 806 return 0; 807 808 out_undo: 809 /* If I have an error cleanup all namespaces I initialized */ 810 list_del(&ops->list); 811 ops_exit_list(ops, &net_exit_list); 812 ops_free_list(ops, &net_exit_list); 813 return error; 814 } 815 816 static void __unregister_pernet_operations(struct pernet_operations *ops) 817 { 818 struct net *net; 819 LIST_HEAD(net_exit_list); 820 821 list_del(&ops->list); 822 for_each_net(net) 823 list_add_tail(&net->exit_list, &net_exit_list); 824 ops_exit_list(ops, &net_exit_list); 825 ops_free_list(ops, &net_exit_list); 826 } 827 828 #else 829 830 static int __register_pernet_operations(struct list_head *list, 831 struct pernet_operations *ops) 832 { 833 if (!init_net_initialized) { 834 list_add_tail(&ops->list, list); 835 return 0; 836 } 837 838 return ops_init(ops, &init_net); 839 } 840 841 static void __unregister_pernet_operations(struct pernet_operations *ops) 842 { 843 if (!init_net_initialized) { 844 list_del(&ops->list); 845 } else { 846 LIST_HEAD(net_exit_list); 847 list_add(&init_net.exit_list, &net_exit_list); 848 ops_exit_list(ops, &net_exit_list); 849 ops_free_list(ops, &net_exit_list); 850 } 851 } 852 853 #endif /* CONFIG_NET_NS */ 854 855 static DEFINE_IDA(net_generic_ids); 856 857 static int register_pernet_operations(struct list_head *list, 858 struct pernet_operations *ops) 859 { 860 int error; 861 862 if (ops->id) { 863 again: 864 error = ida_get_new_above(&net_generic_ids, 1, ops->id); 865 if (error < 0) { 866 if (error == -EAGAIN) { 867 ida_pre_get(&net_generic_ids, GFP_KERNEL); 868 goto again; 869 } 870 return error; 871 } 872 max_gen_ptrs = max_t(unsigned int, max_gen_ptrs, *ops->id); 873 } 874 error = __register_pernet_operations(list, ops); 875 if (error) { 876 rcu_barrier(); 877 if (ops->id) 878 ida_remove(&net_generic_ids, *ops->id); 879 } 880 881 return error; 882 } 883 884 static void unregister_pernet_operations(struct pernet_operations *ops) 885 { 886 887 __unregister_pernet_operations(ops); 888 rcu_barrier(); 889 if (ops->id) 890 ida_remove(&net_generic_ids, *ops->id); 891 } 892 893 /** 894 * register_pernet_subsys - register a network namespace subsystem 895 * @ops: pernet operations structure for the subsystem 896 * 897 * Register a subsystem which has init and exit functions 898 * that are called when network namespaces are created and 899 * destroyed respectively. 900 * 901 * When registered all network namespace init functions are 902 * called for every existing network namespace. Allowing kernel 903 * modules to have a race free view of the set of network namespaces. 904 * 905 * When a new network namespace is created all of the init 906 * methods are called in the order in which they were registered. 907 * 908 * When a network namespace is destroyed all of the exit methods 909 * are called in the reverse of the order with which they were 910 * registered. 911 */ 912 int register_pernet_subsys(struct pernet_operations *ops) 913 { 914 int error; 915 mutex_lock(&net_mutex); 916 error = register_pernet_operations(first_device, ops); 917 mutex_unlock(&net_mutex); 918 return error; 919 } 920 EXPORT_SYMBOL_GPL(register_pernet_subsys); 921 922 /** 923 * unregister_pernet_subsys - unregister a network namespace subsystem 924 * @ops: pernet operations structure to manipulate 925 * 926 * Remove the pernet operations structure from the list to be 927 * used when network namespaces are created or destroyed. In 928 * addition run the exit method for all existing network 929 * namespaces. 930 */ 931 void unregister_pernet_subsys(struct pernet_operations *ops) 932 { 933 mutex_lock(&net_mutex); 934 unregister_pernet_operations(ops); 935 mutex_unlock(&net_mutex); 936 } 937 EXPORT_SYMBOL_GPL(unregister_pernet_subsys); 938 939 /** 940 * register_pernet_device - register a network namespace device 941 * @ops: pernet operations structure for the subsystem 942 * 943 * Register a device which has init and exit functions 944 * that are called when network namespaces are created and 945 * destroyed respectively. 946 * 947 * When registered all network namespace init functions are 948 * called for every existing network namespace. Allowing kernel 949 * modules to have a race free view of the set of network namespaces. 950 * 951 * When a new network namespace is created all of the init 952 * methods are called in the order in which they were registered. 953 * 954 * When a network namespace is destroyed all of the exit methods 955 * are called in the reverse of the order with which they were 956 * registered. 957 */ 958 int register_pernet_device(struct pernet_operations *ops) 959 { 960 int error; 961 mutex_lock(&net_mutex); 962 error = register_pernet_operations(&pernet_list, ops); 963 if (!error && (first_device == &pernet_list)) 964 first_device = &ops->list; 965 mutex_unlock(&net_mutex); 966 return error; 967 } 968 EXPORT_SYMBOL_GPL(register_pernet_device); 969 970 /** 971 * unregister_pernet_device - unregister a network namespace netdevice 972 * @ops: pernet operations structure to manipulate 973 * 974 * Remove the pernet operations structure from the list to be 975 * used when network namespaces are created or destroyed. In 976 * addition run the exit method for all existing network 977 * namespaces. 978 */ 979 void unregister_pernet_device(struct pernet_operations *ops) 980 { 981 mutex_lock(&net_mutex); 982 if (&ops->list == first_device) 983 first_device = first_device->next; 984 unregister_pernet_operations(ops); 985 mutex_unlock(&net_mutex); 986 } 987 EXPORT_SYMBOL_GPL(unregister_pernet_device); 988 989 #ifdef CONFIG_NET_NS 990 static struct ns_common *netns_get(struct task_struct *task) 991 { 992 struct net *net = NULL; 993 struct nsproxy *nsproxy; 994 995 task_lock(task); 996 nsproxy = task->nsproxy; 997 if (nsproxy) 998 net = get_net(nsproxy->net_ns); 999 task_unlock(task); 1000 1001 return net ? &net->ns : NULL; 1002 } 1003 1004 static inline struct net *to_net_ns(struct ns_common *ns) 1005 { 1006 return container_of(ns, struct net, ns); 1007 } 1008 1009 static void netns_put(struct ns_common *ns) 1010 { 1011 put_net(to_net_ns(ns)); 1012 } 1013 1014 static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns) 1015 { 1016 struct net *net = to_net_ns(ns); 1017 1018 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) || 1019 !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) 1020 return -EPERM; 1021 1022 put_net(nsproxy->net_ns); 1023 nsproxy->net_ns = get_net(net); 1024 return 0; 1025 } 1026 1027 static struct user_namespace *netns_owner(struct ns_common *ns) 1028 { 1029 return to_net_ns(ns)->user_ns; 1030 } 1031 1032 const struct proc_ns_operations netns_operations = { 1033 .name = "net", 1034 .type = CLONE_NEWNET, 1035 .get = netns_get, 1036 .put = netns_put, 1037 .install = netns_install, 1038 .owner = netns_owner, 1039 }; 1040 #endif 1041