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