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 unsigned long flags; 219 bool alloc; 220 int id; 221 222 spin_lock_irqsave(&net->nsid_lock, flags); 223 alloc = atomic_read(&peer->count) == 0 ? false : true; 224 id = __peernet2id_alloc(net, peer, &alloc); 225 spin_unlock_irqrestore(&net->nsid_lock, flags); 226 if (alloc && id >= 0) 227 rtnl_net_notifyid(net, RTM_NEWNSID, id); 228 return id; 229 } 230 EXPORT_SYMBOL(peernet2id_alloc); 231 232 /* This function returns, if assigned, the id of a peer netns. */ 233 int peernet2id(struct net *net, struct net *peer) 234 { 235 unsigned long flags; 236 int id; 237 238 spin_lock_irqsave(&net->nsid_lock, flags); 239 id = __peernet2id(net, peer); 240 spin_unlock_irqrestore(&net->nsid_lock, flags); 241 return id; 242 } 243 244 /* This function returns true is the peer netns has an id assigned into the 245 * current netns. 246 */ 247 bool peernet_has_id(struct net *net, struct net *peer) 248 { 249 return peernet2id(net, peer) >= 0; 250 } 251 252 struct net *get_net_ns_by_id(struct net *net, int id) 253 { 254 unsigned long flags; 255 struct net *peer; 256 257 if (id < 0) 258 return NULL; 259 260 rcu_read_lock(); 261 spin_lock_irqsave(&net->nsid_lock, flags); 262 peer = idr_find(&net->netns_ids, id); 263 if (peer) 264 get_net(peer); 265 spin_unlock_irqrestore(&net->nsid_lock, flags); 266 rcu_read_unlock(); 267 268 return peer; 269 } 270 271 /* 272 * setup_net runs the initializers for the network namespace object. 273 */ 274 static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) 275 { 276 /* Must be called with net_mutex held */ 277 const struct pernet_operations *ops, *saved_ops; 278 int error = 0; 279 LIST_HEAD(net_exit_list); 280 281 atomic_set(&net->count, 1); 282 atomic_set(&net->passive, 1); 283 net->dev_base_seq = 1; 284 net->user_ns = user_ns; 285 idr_init(&net->netns_ids); 286 spin_lock_init(&net->nsid_lock); 287 288 list_for_each_entry(ops, &pernet_list, list) { 289 error = ops_init(ops, net); 290 if (error < 0) 291 goto out_undo; 292 } 293 out: 294 return error; 295 296 out_undo: 297 /* Walk through the list backwards calling the exit functions 298 * for the pernet modules whose init functions did not fail. 299 */ 300 list_add(&net->exit_list, &net_exit_list); 301 saved_ops = ops; 302 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 303 ops_exit_list(ops, &net_exit_list); 304 305 ops = saved_ops; 306 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 307 ops_free_list(ops, &net_exit_list); 308 309 rcu_barrier(); 310 goto out; 311 } 312 313 314 #ifdef CONFIG_NET_NS 315 static struct kmem_cache *net_cachep; 316 static struct workqueue_struct *netns_wq; 317 318 static struct net *net_alloc(void) 319 { 320 struct net *net = NULL; 321 struct net_generic *ng; 322 323 ng = net_alloc_generic(); 324 if (!ng) 325 goto out; 326 327 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL); 328 if (!net) 329 goto out_free; 330 331 rcu_assign_pointer(net->gen, ng); 332 out: 333 return net; 334 335 out_free: 336 kfree(ng); 337 goto out; 338 } 339 340 static void net_free(struct net *net) 341 { 342 kfree(rcu_access_pointer(net->gen)); 343 kmem_cache_free(net_cachep, net); 344 } 345 346 void net_drop_ns(void *p) 347 { 348 struct net *ns = p; 349 if (ns && atomic_dec_and_test(&ns->passive)) 350 net_free(ns); 351 } 352 353 struct net *copy_net_ns(unsigned long flags, 354 struct user_namespace *user_ns, struct net *old_net) 355 { 356 struct net *net; 357 int rv; 358 359 if (!(flags & CLONE_NEWNET)) 360 return get_net(old_net); 361 362 net = net_alloc(); 363 if (!net) 364 return ERR_PTR(-ENOMEM); 365 366 get_user_ns(user_ns); 367 368 mutex_lock(&net_mutex); 369 rv = setup_net(net, user_ns); 370 if (rv == 0) { 371 rtnl_lock(); 372 list_add_tail_rcu(&net->list, &net_namespace_list); 373 rtnl_unlock(); 374 } 375 mutex_unlock(&net_mutex); 376 if (rv < 0) { 377 put_user_ns(user_ns); 378 net_drop_ns(net); 379 return ERR_PTR(rv); 380 } 381 return net; 382 } 383 384 static DEFINE_SPINLOCK(cleanup_list_lock); 385 static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */ 386 387 static void cleanup_net(struct work_struct *work) 388 { 389 const struct pernet_operations *ops; 390 struct net *net, *tmp; 391 struct list_head net_kill_list; 392 LIST_HEAD(net_exit_list); 393 394 /* Atomically snapshot the list of namespaces to cleanup */ 395 spin_lock_irq(&cleanup_list_lock); 396 list_replace_init(&cleanup_list, &net_kill_list); 397 spin_unlock_irq(&cleanup_list_lock); 398 399 mutex_lock(&net_mutex); 400 401 /* Don't let anyone else find us. */ 402 rtnl_lock(); 403 list_for_each_entry(net, &net_kill_list, cleanup_list) { 404 list_del_rcu(&net->list); 405 list_add_tail(&net->exit_list, &net_exit_list); 406 for_each_net(tmp) { 407 int id; 408 409 spin_lock_irq(&tmp->nsid_lock); 410 id = __peernet2id(tmp, net); 411 if (id >= 0) 412 idr_remove(&tmp->netns_ids, id); 413 spin_unlock_irq(&tmp->nsid_lock); 414 if (id >= 0) 415 rtnl_net_notifyid(tmp, RTM_DELNSID, id); 416 } 417 spin_lock_irq(&net->nsid_lock); 418 idr_destroy(&net->netns_ids); 419 spin_unlock_irq(&net->nsid_lock); 420 421 } 422 rtnl_unlock(); 423 424 /* 425 * Another CPU might be rcu-iterating the list, wait for it. 426 * This needs to be before calling the exit() notifiers, so 427 * the rcu_barrier() below isn't sufficient alone. 428 */ 429 synchronize_rcu(); 430 431 /* Run all of the network namespace exit methods */ 432 list_for_each_entry_reverse(ops, &pernet_list, list) 433 ops_exit_list(ops, &net_exit_list); 434 435 /* Free the net generic variables */ 436 list_for_each_entry_reverse(ops, &pernet_list, list) 437 ops_free_list(ops, &net_exit_list); 438 439 mutex_unlock(&net_mutex); 440 441 /* Ensure there are no outstanding rcu callbacks using this 442 * network namespace. 443 */ 444 rcu_barrier(); 445 446 /* Finally it is safe to free my network namespace structure */ 447 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { 448 list_del_init(&net->exit_list); 449 put_user_ns(net->user_ns); 450 net_drop_ns(net); 451 } 452 } 453 static DECLARE_WORK(net_cleanup_work, cleanup_net); 454 455 void __put_net(struct net *net) 456 { 457 /* Cleanup the network namespace in process context */ 458 unsigned long flags; 459 460 spin_lock_irqsave(&cleanup_list_lock, flags); 461 list_add(&net->cleanup_list, &cleanup_list); 462 spin_unlock_irqrestore(&cleanup_list_lock, flags); 463 464 queue_work(netns_wq, &net_cleanup_work); 465 } 466 EXPORT_SYMBOL_GPL(__put_net); 467 468 struct net *get_net_ns_by_fd(int fd) 469 { 470 struct file *file; 471 struct ns_common *ns; 472 struct net *net; 473 474 file = proc_ns_fget(fd); 475 if (IS_ERR(file)) 476 return ERR_CAST(file); 477 478 ns = get_proc_ns(file_inode(file)); 479 if (ns->ops == &netns_operations) 480 net = get_net(container_of(ns, struct net, ns)); 481 else 482 net = ERR_PTR(-EINVAL); 483 484 fput(file); 485 return net; 486 } 487 488 #else 489 struct net *get_net_ns_by_fd(int fd) 490 { 491 return ERR_PTR(-EINVAL); 492 } 493 #endif 494 EXPORT_SYMBOL_GPL(get_net_ns_by_fd); 495 496 struct net *get_net_ns_by_pid(pid_t pid) 497 { 498 struct task_struct *tsk; 499 struct net *net; 500 501 /* Lookup the network namespace */ 502 net = ERR_PTR(-ESRCH); 503 rcu_read_lock(); 504 tsk = find_task_by_vpid(pid); 505 if (tsk) { 506 struct nsproxy *nsproxy; 507 task_lock(tsk); 508 nsproxy = tsk->nsproxy; 509 if (nsproxy) 510 net = get_net(nsproxy->net_ns); 511 task_unlock(tsk); 512 } 513 rcu_read_unlock(); 514 return net; 515 } 516 EXPORT_SYMBOL_GPL(get_net_ns_by_pid); 517 518 static __net_init int net_ns_net_init(struct net *net) 519 { 520 #ifdef CONFIG_NET_NS 521 net->ns.ops = &netns_operations; 522 #endif 523 return ns_alloc_inum(&net->ns); 524 } 525 526 static __net_exit void net_ns_net_exit(struct net *net) 527 { 528 ns_free_inum(&net->ns); 529 } 530 531 static struct pernet_operations __net_initdata net_ns_ops = { 532 .init = net_ns_net_init, 533 .exit = net_ns_net_exit, 534 }; 535 536 static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = { 537 [NETNSA_NONE] = { .type = NLA_UNSPEC }, 538 [NETNSA_NSID] = { .type = NLA_S32 }, 539 [NETNSA_PID] = { .type = NLA_U32 }, 540 [NETNSA_FD] = { .type = NLA_U32 }, 541 }; 542 543 static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh) 544 { 545 struct net *net = sock_net(skb->sk); 546 struct nlattr *tb[NETNSA_MAX + 1]; 547 unsigned long flags; 548 struct net *peer; 549 int nsid, err; 550 551 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, 552 rtnl_net_policy); 553 if (err < 0) 554 return err; 555 if (!tb[NETNSA_NSID]) 556 return -EINVAL; 557 nsid = nla_get_s32(tb[NETNSA_NSID]); 558 559 if (tb[NETNSA_PID]) 560 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 561 else if (tb[NETNSA_FD]) 562 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 563 else 564 return -EINVAL; 565 if (IS_ERR(peer)) 566 return PTR_ERR(peer); 567 568 spin_lock_irqsave(&net->nsid_lock, flags); 569 if (__peernet2id(net, peer) >= 0) { 570 spin_unlock_irqrestore(&net->nsid_lock, flags); 571 err = -EEXIST; 572 goto out; 573 } 574 575 err = alloc_netid(net, peer, nsid); 576 spin_unlock_irqrestore(&net->nsid_lock, flags); 577 if (err >= 0) { 578 rtnl_net_notifyid(net, RTM_NEWNSID, err); 579 err = 0; 580 } 581 out: 582 put_net(peer); 583 return err; 584 } 585 586 static int rtnl_net_get_size(void) 587 { 588 return NLMSG_ALIGN(sizeof(struct rtgenmsg)) 589 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */ 590 ; 591 } 592 593 static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags, 594 int cmd, struct net *net, int nsid) 595 { 596 struct nlmsghdr *nlh; 597 struct rtgenmsg *rth; 598 599 nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rth), flags); 600 if (!nlh) 601 return -EMSGSIZE; 602 603 rth = nlmsg_data(nlh); 604 rth->rtgen_family = AF_UNSPEC; 605 606 if (nla_put_s32(skb, NETNSA_NSID, nsid)) 607 goto nla_put_failure; 608 609 nlmsg_end(skb, nlh); 610 return 0; 611 612 nla_put_failure: 613 nlmsg_cancel(skb, nlh); 614 return -EMSGSIZE; 615 } 616 617 static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh) 618 { 619 struct net *net = sock_net(skb->sk); 620 struct nlattr *tb[NETNSA_MAX + 1]; 621 struct sk_buff *msg; 622 struct net *peer; 623 int err, id; 624 625 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, 626 rtnl_net_policy); 627 if (err < 0) 628 return err; 629 if (tb[NETNSA_PID]) 630 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 631 else if (tb[NETNSA_FD]) 632 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 633 else 634 return -EINVAL; 635 636 if (IS_ERR(peer)) 637 return PTR_ERR(peer); 638 639 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 640 if (!msg) { 641 err = -ENOMEM; 642 goto out; 643 } 644 645 id = peernet2id(net, peer); 646 err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0, 647 RTM_NEWNSID, net, id); 648 if (err < 0) 649 goto err_out; 650 651 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid); 652 goto out; 653 654 err_out: 655 nlmsg_free(msg); 656 out: 657 put_net(peer); 658 return err; 659 } 660 661 struct rtnl_net_dump_cb { 662 struct net *net; 663 struct sk_buff *skb; 664 struct netlink_callback *cb; 665 int idx; 666 int s_idx; 667 }; 668 669 static int rtnl_net_dumpid_one(int id, void *peer, void *data) 670 { 671 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data; 672 int ret; 673 674 if (net_cb->idx < net_cb->s_idx) 675 goto cont; 676 677 ret = rtnl_net_fill(net_cb->skb, NETLINK_CB(net_cb->cb->skb).portid, 678 net_cb->cb->nlh->nlmsg_seq, NLM_F_MULTI, 679 RTM_NEWNSID, net_cb->net, id); 680 if (ret < 0) 681 return ret; 682 683 cont: 684 net_cb->idx++; 685 return 0; 686 } 687 688 static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb) 689 { 690 struct net *net = sock_net(skb->sk); 691 struct rtnl_net_dump_cb net_cb = { 692 .net = net, 693 .skb = skb, 694 .cb = cb, 695 .idx = 0, 696 .s_idx = cb->args[0], 697 }; 698 unsigned long flags; 699 700 spin_lock_irqsave(&net->nsid_lock, flags); 701 idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb); 702 spin_unlock_irqrestore(&net->nsid_lock, flags); 703 704 cb->args[0] = net_cb.idx; 705 return skb->len; 706 } 707 708 static void rtnl_net_notifyid(struct net *net, int cmd, int id) 709 { 710 struct sk_buff *msg; 711 int err = -ENOMEM; 712 713 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 714 if (!msg) 715 goto out; 716 717 err = rtnl_net_fill(msg, 0, 0, 0, cmd, net, id); 718 if (err < 0) 719 goto err_out; 720 721 rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0); 722 return; 723 724 err_out: 725 nlmsg_free(msg); 726 out: 727 rtnl_set_sk_err(net, RTNLGRP_NSID, err); 728 } 729 730 static int __init net_ns_init(void) 731 { 732 struct net_generic *ng; 733 734 #ifdef CONFIG_NET_NS 735 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), 736 SMP_CACHE_BYTES, 737 SLAB_PANIC, NULL); 738 739 /* Create workqueue for cleanup */ 740 netns_wq = create_singlethread_workqueue("netns"); 741 if (!netns_wq) 742 panic("Could not create netns workq"); 743 #endif 744 745 ng = net_alloc_generic(); 746 if (!ng) 747 panic("Could not allocate generic netns"); 748 749 rcu_assign_pointer(init_net.gen, ng); 750 751 mutex_lock(&net_mutex); 752 if (setup_net(&init_net, &init_user_ns)) 753 panic("Could not setup the initial network namespace"); 754 755 init_net_initialized = true; 756 757 rtnl_lock(); 758 list_add_tail_rcu(&init_net.list, &net_namespace_list); 759 rtnl_unlock(); 760 761 mutex_unlock(&net_mutex); 762 763 register_pernet_subsys(&net_ns_ops); 764 765 rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, NULL); 766 rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid, 767 NULL); 768 769 return 0; 770 } 771 772 pure_initcall(net_ns_init); 773 774 #ifdef CONFIG_NET_NS 775 static int __register_pernet_operations(struct list_head *list, 776 struct pernet_operations *ops) 777 { 778 struct net *net; 779 int error; 780 LIST_HEAD(net_exit_list); 781 782 list_add_tail(&ops->list, list); 783 if (ops->init || (ops->id && ops->size)) { 784 for_each_net(net) { 785 error = ops_init(ops, net); 786 if (error) 787 goto out_undo; 788 list_add_tail(&net->exit_list, &net_exit_list); 789 } 790 } 791 return 0; 792 793 out_undo: 794 /* If I have an error cleanup all namespaces I initialized */ 795 list_del(&ops->list); 796 ops_exit_list(ops, &net_exit_list); 797 ops_free_list(ops, &net_exit_list); 798 return error; 799 } 800 801 static void __unregister_pernet_operations(struct pernet_operations *ops) 802 { 803 struct net *net; 804 LIST_HEAD(net_exit_list); 805 806 list_del(&ops->list); 807 for_each_net(net) 808 list_add_tail(&net->exit_list, &net_exit_list); 809 ops_exit_list(ops, &net_exit_list); 810 ops_free_list(ops, &net_exit_list); 811 } 812 813 #else 814 815 static int __register_pernet_operations(struct list_head *list, 816 struct pernet_operations *ops) 817 { 818 if (!init_net_initialized) { 819 list_add_tail(&ops->list, list); 820 return 0; 821 } 822 823 return ops_init(ops, &init_net); 824 } 825 826 static void __unregister_pernet_operations(struct pernet_operations *ops) 827 { 828 if (!init_net_initialized) { 829 list_del(&ops->list); 830 } else { 831 LIST_HEAD(net_exit_list); 832 list_add(&init_net.exit_list, &net_exit_list); 833 ops_exit_list(ops, &net_exit_list); 834 ops_free_list(ops, &net_exit_list); 835 } 836 } 837 838 #endif /* CONFIG_NET_NS */ 839 840 static DEFINE_IDA(net_generic_ids); 841 842 static int register_pernet_operations(struct list_head *list, 843 struct pernet_operations *ops) 844 { 845 int error; 846 847 if (ops->id) { 848 again: 849 error = ida_get_new_above(&net_generic_ids, 1, ops->id); 850 if (error < 0) { 851 if (error == -EAGAIN) { 852 ida_pre_get(&net_generic_ids, GFP_KERNEL); 853 goto again; 854 } 855 return error; 856 } 857 max_gen_ptrs = max_t(unsigned int, max_gen_ptrs, *ops->id); 858 } 859 error = __register_pernet_operations(list, ops); 860 if (error) { 861 rcu_barrier(); 862 if (ops->id) 863 ida_remove(&net_generic_ids, *ops->id); 864 } 865 866 return error; 867 } 868 869 static void unregister_pernet_operations(struct pernet_operations *ops) 870 { 871 872 __unregister_pernet_operations(ops); 873 rcu_barrier(); 874 if (ops->id) 875 ida_remove(&net_generic_ids, *ops->id); 876 } 877 878 /** 879 * register_pernet_subsys - register a network namespace subsystem 880 * @ops: pernet operations structure for the subsystem 881 * 882 * Register a subsystem which has init and exit functions 883 * that are called when network namespaces are created and 884 * destroyed respectively. 885 * 886 * When registered all network namespace init functions are 887 * called for every existing network namespace. Allowing kernel 888 * modules to have a race free view of the set of network namespaces. 889 * 890 * When a new network namespace is created all of the init 891 * methods are called in the order in which they were registered. 892 * 893 * When a network namespace is destroyed all of the exit methods 894 * are called in the reverse of the order with which they were 895 * registered. 896 */ 897 int register_pernet_subsys(struct pernet_operations *ops) 898 { 899 int error; 900 mutex_lock(&net_mutex); 901 error = register_pernet_operations(first_device, ops); 902 mutex_unlock(&net_mutex); 903 return error; 904 } 905 EXPORT_SYMBOL_GPL(register_pernet_subsys); 906 907 /** 908 * unregister_pernet_subsys - unregister a network namespace subsystem 909 * @ops: pernet operations structure to manipulate 910 * 911 * Remove the pernet operations structure from the list to be 912 * used when network namespaces are created or destroyed. In 913 * addition run the exit method for all existing network 914 * namespaces. 915 */ 916 void unregister_pernet_subsys(struct pernet_operations *ops) 917 { 918 mutex_lock(&net_mutex); 919 unregister_pernet_operations(ops); 920 mutex_unlock(&net_mutex); 921 } 922 EXPORT_SYMBOL_GPL(unregister_pernet_subsys); 923 924 /** 925 * register_pernet_device - register a network namespace device 926 * @ops: pernet operations structure for the subsystem 927 * 928 * Register a device which has init and exit functions 929 * that are called when network namespaces are created and 930 * destroyed respectively. 931 * 932 * When registered all network namespace init functions are 933 * called for every existing network namespace. Allowing kernel 934 * modules to have a race free view of the set of network namespaces. 935 * 936 * When a new network namespace is created all of the init 937 * methods are called in the order in which they were registered. 938 * 939 * When a network namespace is destroyed all of the exit methods 940 * are called in the reverse of the order with which they were 941 * registered. 942 */ 943 int register_pernet_device(struct pernet_operations *ops) 944 { 945 int error; 946 mutex_lock(&net_mutex); 947 error = register_pernet_operations(&pernet_list, ops); 948 if (!error && (first_device == &pernet_list)) 949 first_device = &ops->list; 950 mutex_unlock(&net_mutex); 951 return error; 952 } 953 EXPORT_SYMBOL_GPL(register_pernet_device); 954 955 /** 956 * unregister_pernet_device - unregister a network namespace netdevice 957 * @ops: pernet operations structure to manipulate 958 * 959 * Remove the pernet operations structure from the list to be 960 * used when network namespaces are created or destroyed. In 961 * addition run the exit method for all existing network 962 * namespaces. 963 */ 964 void unregister_pernet_device(struct pernet_operations *ops) 965 { 966 mutex_lock(&net_mutex); 967 if (&ops->list == first_device) 968 first_device = first_device->next; 969 unregister_pernet_operations(ops); 970 mutex_unlock(&net_mutex); 971 } 972 EXPORT_SYMBOL_GPL(unregister_pernet_device); 973 974 #ifdef CONFIG_NET_NS 975 static struct ns_common *netns_get(struct task_struct *task) 976 { 977 struct net *net = NULL; 978 struct nsproxy *nsproxy; 979 980 task_lock(task); 981 nsproxy = task->nsproxy; 982 if (nsproxy) 983 net = get_net(nsproxy->net_ns); 984 task_unlock(task); 985 986 return net ? &net->ns : NULL; 987 } 988 989 static inline struct net *to_net_ns(struct ns_common *ns) 990 { 991 return container_of(ns, struct net, ns); 992 } 993 994 static void netns_put(struct ns_common *ns) 995 { 996 put_net(to_net_ns(ns)); 997 } 998 999 static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns) 1000 { 1001 struct net *net = to_net_ns(ns); 1002 1003 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) || 1004 !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) 1005 return -EPERM; 1006 1007 put_net(nsproxy->net_ns); 1008 nsproxy->net_ns = get_net(net); 1009 return 0; 1010 } 1011 1012 const struct proc_ns_operations netns_operations = { 1013 .name = "net", 1014 .type = CLONE_NEWNET, 1015 .get = netns_get, 1016 .put = netns_put, 1017 .install = netns_install, 1018 }; 1019 #endif 1020