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 <linux/sched/task.h> 20 21 #include <net/sock.h> 22 #include <net/netlink.h> 23 #include <net/net_namespace.h> 24 #include <net/netns/generic.h> 25 26 /* 27 * Our network namespace constructor/destructor lists 28 */ 29 30 static LIST_HEAD(pernet_list); 31 static struct list_head *first_device = &pernet_list; 32 /* Used only if there are !async pernet_operations registered */ 33 DEFINE_MUTEX(net_mutex); 34 35 LIST_HEAD(net_namespace_list); 36 EXPORT_SYMBOL_GPL(net_namespace_list); 37 38 struct net init_net = { 39 .count = REFCOUNT_INIT(1), 40 .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head), 41 }; 42 EXPORT_SYMBOL(init_net); 43 44 static bool init_net_initialized; 45 static unsigned nr_sync_pernet_ops; 46 /* 47 * net_sem: protects: pernet_list, net_generic_ids, nr_sync_pernet_ops, 48 * init_net_initialized and first_device pointer. 49 */ 50 DECLARE_RWSEM(net_sem); 51 52 #define MIN_PERNET_OPS_ID \ 53 ((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *)) 54 55 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */ 56 57 static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS; 58 59 static struct net_generic *net_alloc_generic(void) 60 { 61 struct net_generic *ng; 62 unsigned int generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]); 63 64 ng = kzalloc(generic_size, GFP_KERNEL); 65 if (ng) 66 ng->s.len = max_gen_ptrs; 67 68 return ng; 69 } 70 71 static int net_assign_generic(struct net *net, unsigned int id, void *data) 72 { 73 struct net_generic *ng, *old_ng; 74 75 BUG_ON(id < MIN_PERNET_OPS_ID); 76 77 old_ng = rcu_dereference_protected(net->gen, 78 lockdep_is_held(&net_sem)); 79 if (old_ng->s.len > id) { 80 old_ng->ptr[id] = data; 81 return 0; 82 } 83 84 ng = net_alloc_generic(); 85 if (ng == NULL) 86 return -ENOMEM; 87 88 /* 89 * Some synchronisation notes: 90 * 91 * The net_generic explores the net->gen array inside rcu 92 * read section. Besides once set the net->gen->ptr[x] 93 * pointer never changes (see rules in netns/generic.h). 94 * 95 * That said, we simply duplicate this array and schedule 96 * the old copy for kfree after a grace period. 97 */ 98 99 memcpy(&ng->ptr[MIN_PERNET_OPS_ID], &old_ng->ptr[MIN_PERNET_OPS_ID], 100 (old_ng->s.len - MIN_PERNET_OPS_ID) * sizeof(void *)); 101 ng->ptr[id] = data; 102 103 rcu_assign_pointer(net->gen, ng); 104 kfree_rcu(old_ng, s.rcu); 105 return 0; 106 } 107 108 static int ops_init(const struct pernet_operations *ops, struct net *net) 109 { 110 int err = -ENOMEM; 111 void *data = NULL; 112 113 if (ops->id && ops->size) { 114 data = kzalloc(ops->size, GFP_KERNEL); 115 if (!data) 116 goto out; 117 118 err = net_assign_generic(net, *ops->id, data); 119 if (err) 120 goto cleanup; 121 } 122 err = 0; 123 if (ops->init) 124 err = ops->init(net); 125 if (!err) 126 return 0; 127 128 cleanup: 129 kfree(data); 130 131 out: 132 return err; 133 } 134 135 static void ops_free(const struct pernet_operations *ops, struct net *net) 136 { 137 if (ops->id && ops->size) { 138 kfree(net_generic(net, *ops->id)); 139 } 140 } 141 142 static void ops_exit_list(const struct pernet_operations *ops, 143 struct list_head *net_exit_list) 144 { 145 struct net *net; 146 if (ops->exit) { 147 list_for_each_entry(net, net_exit_list, exit_list) 148 ops->exit(net); 149 } 150 if (ops->exit_batch) 151 ops->exit_batch(net_exit_list); 152 } 153 154 static void ops_free_list(const struct pernet_operations *ops, 155 struct list_head *net_exit_list) 156 { 157 struct net *net; 158 if (ops->size && ops->id) { 159 list_for_each_entry(net, net_exit_list, exit_list) 160 ops_free(ops, net); 161 } 162 } 163 164 /* should be called with nsid_lock held */ 165 static int alloc_netid(struct net *net, struct net *peer, int reqid) 166 { 167 int min = 0, max = 0; 168 169 if (reqid >= 0) { 170 min = reqid; 171 max = reqid + 1; 172 } 173 174 return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC); 175 } 176 177 /* This function is used by idr_for_each(). If net is equal to peer, the 178 * function returns the id so that idr_for_each() stops. Because we cannot 179 * returns the id 0 (idr_for_each() will not stop), we return the magic value 180 * NET_ID_ZERO (-1) for it. 181 */ 182 #define NET_ID_ZERO -1 183 static int net_eq_idr(int id, void *net, void *peer) 184 { 185 if (net_eq(net, peer)) 186 return id ? : NET_ID_ZERO; 187 return 0; 188 } 189 190 /* Should be called with nsid_lock held. If a new id is assigned, the bool alloc 191 * is set to true, thus the caller knows that the new id must be notified via 192 * rtnl. 193 */ 194 static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc) 195 { 196 int id = idr_for_each(&net->netns_ids, net_eq_idr, peer); 197 bool alloc_it = *alloc; 198 199 *alloc = false; 200 201 /* Magic value for id 0. */ 202 if (id == NET_ID_ZERO) 203 return 0; 204 if (id > 0) 205 return id; 206 207 if (alloc_it) { 208 id = alloc_netid(net, peer, -1); 209 *alloc = true; 210 return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED; 211 } 212 213 return NETNSA_NSID_NOT_ASSIGNED; 214 } 215 216 /* should be called with nsid_lock held */ 217 static int __peernet2id(struct net *net, struct net *peer) 218 { 219 bool no = false; 220 221 return __peernet2id_alloc(net, peer, &no); 222 } 223 224 static void rtnl_net_notifyid(struct net *net, int cmd, int id); 225 /* This function returns the id of a peer netns. If no id is assigned, one will 226 * be allocated and returned. 227 */ 228 int peernet2id_alloc(struct net *net, struct net *peer) 229 { 230 bool alloc = false, alive = false; 231 int id; 232 233 if (refcount_read(&net->count) == 0) 234 return NETNSA_NSID_NOT_ASSIGNED; 235 spin_lock_bh(&net->nsid_lock); 236 /* 237 * When peer is obtained from RCU lists, we may race with 238 * its cleanup. Check whether it's alive, and this guarantees 239 * we never hash a peer back to net->netns_ids, after it has 240 * just been idr_remove()'d from there in cleanup_net(). 241 */ 242 if (maybe_get_net(peer)) 243 alive = alloc = true; 244 id = __peernet2id_alloc(net, peer, &alloc); 245 spin_unlock_bh(&net->nsid_lock); 246 if (alloc && id >= 0) 247 rtnl_net_notifyid(net, RTM_NEWNSID, id); 248 if (alive) 249 put_net(peer); 250 return id; 251 } 252 EXPORT_SYMBOL_GPL(peernet2id_alloc); 253 254 /* This function returns, if assigned, the id of a peer netns. */ 255 int peernet2id(struct net *net, struct net *peer) 256 { 257 int id; 258 259 spin_lock_bh(&net->nsid_lock); 260 id = __peernet2id(net, peer); 261 spin_unlock_bh(&net->nsid_lock); 262 return id; 263 } 264 EXPORT_SYMBOL(peernet2id); 265 266 /* This function returns true is the peer netns has an id assigned into the 267 * current netns. 268 */ 269 bool peernet_has_id(struct net *net, struct net *peer) 270 { 271 return peernet2id(net, peer) >= 0; 272 } 273 274 struct net *get_net_ns_by_id(struct net *net, int id) 275 { 276 struct net *peer; 277 278 if (id < 0) 279 return NULL; 280 281 rcu_read_lock(); 282 peer = idr_find(&net->netns_ids, id); 283 if (peer) 284 peer = maybe_get_net(peer); 285 rcu_read_unlock(); 286 287 return peer; 288 } 289 290 /* 291 * setup_net runs the initializers for the network namespace object. 292 */ 293 static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) 294 { 295 /* Must be called with net_sem held */ 296 const struct pernet_operations *ops, *saved_ops; 297 int error = 0; 298 LIST_HEAD(net_exit_list); 299 300 refcount_set(&net->count, 1); 301 refcount_set(&net->passive, 1); 302 net->dev_base_seq = 1; 303 net->user_ns = user_ns; 304 idr_init(&net->netns_ids); 305 spin_lock_init(&net->nsid_lock); 306 307 list_for_each_entry(ops, &pernet_list, list) { 308 error = ops_init(ops, net); 309 if (error < 0) 310 goto out_undo; 311 } 312 rtnl_lock(); 313 list_add_tail_rcu(&net->list, &net_namespace_list); 314 rtnl_unlock(); 315 out: 316 return error; 317 318 out_undo: 319 /* Walk through the list backwards calling the exit functions 320 * for the pernet modules whose init functions did not fail. 321 */ 322 list_add(&net->exit_list, &net_exit_list); 323 saved_ops = ops; 324 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 325 ops_exit_list(ops, &net_exit_list); 326 327 ops = saved_ops; 328 list_for_each_entry_continue_reverse(ops, &pernet_list, list) 329 ops_free_list(ops, &net_exit_list); 330 331 rcu_barrier(); 332 goto out; 333 } 334 335 static int __net_init net_defaults_init_net(struct net *net) 336 { 337 net->core.sysctl_somaxconn = SOMAXCONN; 338 return 0; 339 } 340 341 static struct pernet_operations net_defaults_ops = { 342 .init = net_defaults_init_net, 343 }; 344 345 static __init int net_defaults_init(void) 346 { 347 if (register_pernet_subsys(&net_defaults_ops)) 348 panic("Cannot initialize net default settings"); 349 350 return 0; 351 } 352 353 core_initcall(net_defaults_init); 354 355 #ifdef CONFIG_NET_NS 356 static struct ucounts *inc_net_namespaces(struct user_namespace *ns) 357 { 358 return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES); 359 } 360 361 static void dec_net_namespaces(struct ucounts *ucounts) 362 { 363 dec_ucount(ucounts, UCOUNT_NET_NAMESPACES); 364 } 365 366 static struct kmem_cache *net_cachep; 367 static struct workqueue_struct *netns_wq; 368 369 static struct net *net_alloc(void) 370 { 371 struct net *net = NULL; 372 struct net_generic *ng; 373 374 ng = net_alloc_generic(); 375 if (!ng) 376 goto out; 377 378 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL); 379 if (!net) 380 goto out_free; 381 382 rcu_assign_pointer(net->gen, ng); 383 out: 384 return net; 385 386 out_free: 387 kfree(ng); 388 goto out; 389 } 390 391 static void net_free(struct net *net) 392 { 393 kfree(rcu_access_pointer(net->gen)); 394 kmem_cache_free(net_cachep, net); 395 } 396 397 void net_drop_ns(void *p) 398 { 399 struct net *ns = p; 400 if (ns && refcount_dec_and_test(&ns->passive)) 401 net_free(ns); 402 } 403 404 struct net *copy_net_ns(unsigned long flags, 405 struct user_namespace *user_ns, struct net *old_net) 406 { 407 struct ucounts *ucounts; 408 struct net *net; 409 int rv; 410 411 if (!(flags & CLONE_NEWNET)) 412 return get_net(old_net); 413 414 ucounts = inc_net_namespaces(user_ns); 415 if (!ucounts) 416 return ERR_PTR(-ENOSPC); 417 418 net = net_alloc(); 419 if (!net) { 420 rv = -ENOMEM; 421 goto dec_ucounts; 422 } 423 refcount_set(&net->passive, 1); 424 net->ucounts = ucounts; 425 get_user_ns(user_ns); 426 427 rv = down_read_killable(&net_sem); 428 if (rv < 0) 429 goto put_userns; 430 if (nr_sync_pernet_ops) { 431 rv = mutex_lock_killable(&net_mutex); 432 if (rv < 0) 433 goto up_read; 434 } 435 rv = setup_net(net, user_ns); 436 if (nr_sync_pernet_ops) 437 mutex_unlock(&net_mutex); 438 up_read: 439 up_read(&net_sem); 440 if (rv < 0) { 441 put_userns: 442 put_user_ns(user_ns); 443 net_drop_ns(net); 444 dec_ucounts: 445 dec_net_namespaces(ucounts); 446 return ERR_PTR(rv); 447 } 448 return net; 449 } 450 451 static void unhash_nsid(struct net *net, struct net *last) 452 { 453 struct net *tmp; 454 /* This function is only called from cleanup_net() work, 455 * and this work is the only process, that may delete 456 * a net from net_namespace_list. So, when the below 457 * is executing, the list may only grow. Thus, we do not 458 * use for_each_net_rcu() or rtnl_lock(). 459 */ 460 for_each_net(tmp) { 461 int id; 462 463 spin_lock_bh(&tmp->nsid_lock); 464 id = __peernet2id(tmp, net); 465 if (id >= 0) 466 idr_remove(&tmp->netns_ids, id); 467 spin_unlock_bh(&tmp->nsid_lock); 468 if (id >= 0) 469 rtnl_net_notifyid(tmp, RTM_DELNSID, id); 470 if (tmp == last) 471 break; 472 } 473 spin_lock_bh(&net->nsid_lock); 474 idr_destroy(&net->netns_ids); 475 spin_unlock_bh(&net->nsid_lock); 476 } 477 478 static DEFINE_SPINLOCK(cleanup_list_lock); 479 static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */ 480 481 static void cleanup_net(struct work_struct *work) 482 { 483 const struct pernet_operations *ops; 484 struct net *net, *tmp, *last; 485 struct list_head net_kill_list; 486 LIST_HEAD(net_exit_list); 487 488 /* Atomically snapshot the list of namespaces to cleanup */ 489 spin_lock_irq(&cleanup_list_lock); 490 list_replace_init(&cleanup_list, &net_kill_list); 491 spin_unlock_irq(&cleanup_list_lock); 492 493 down_read(&net_sem); 494 if (nr_sync_pernet_ops) 495 mutex_lock(&net_mutex); 496 497 /* Don't let anyone else find us. */ 498 rtnl_lock(); 499 list_for_each_entry(net, &net_kill_list, cleanup_list) 500 list_del_rcu(&net->list); 501 /* Cache last net. After we unlock rtnl, no one new net 502 * added to net_namespace_list can assign nsid pointer 503 * to a net from net_kill_list (see peernet2id_alloc()). 504 * So, we skip them in unhash_nsid(). 505 * 506 * Note, that unhash_nsid() does not delete nsid links 507 * between net_kill_list's nets, as they've already 508 * deleted from net_namespace_list. But, this would be 509 * useless anyway, as netns_ids are destroyed there. 510 */ 511 last = list_last_entry(&net_namespace_list, struct net, list); 512 rtnl_unlock(); 513 514 list_for_each_entry(net, &net_kill_list, cleanup_list) { 515 unhash_nsid(net, last); 516 list_add_tail(&net->exit_list, &net_exit_list); 517 } 518 519 /* 520 * Another CPU might be rcu-iterating the list, wait for it. 521 * This needs to be before calling the exit() notifiers, so 522 * the rcu_barrier() below isn't sufficient alone. 523 */ 524 synchronize_rcu(); 525 526 /* Run all of the network namespace exit methods */ 527 list_for_each_entry_reverse(ops, &pernet_list, list) 528 ops_exit_list(ops, &net_exit_list); 529 530 if (nr_sync_pernet_ops) 531 mutex_unlock(&net_mutex); 532 533 /* Free the net generic variables */ 534 list_for_each_entry_reverse(ops, &pernet_list, list) 535 ops_free_list(ops, &net_exit_list); 536 537 up_read(&net_sem); 538 539 /* Ensure there are no outstanding rcu callbacks using this 540 * network namespace. 541 */ 542 rcu_barrier(); 543 544 /* Finally it is safe to free my network namespace structure */ 545 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { 546 list_del_init(&net->exit_list); 547 dec_net_namespaces(net->ucounts); 548 put_user_ns(net->user_ns); 549 net_drop_ns(net); 550 } 551 } 552 553 /** 554 * net_ns_barrier - wait until concurrent net_cleanup_work is done 555 * 556 * cleanup_net runs from work queue and will first remove namespaces 557 * from the global list, then run net exit functions. 558 * 559 * Call this in module exit path to make sure that all netns 560 * ->exit ops have been invoked before the function is removed. 561 */ 562 void net_ns_barrier(void) 563 { 564 down_write(&net_sem); 565 mutex_lock(&net_mutex); 566 mutex_unlock(&net_mutex); 567 up_write(&net_sem); 568 } 569 EXPORT_SYMBOL(net_ns_barrier); 570 571 static DECLARE_WORK(net_cleanup_work, cleanup_net); 572 573 void __put_net(struct net *net) 574 { 575 /* Cleanup the network namespace in process context */ 576 unsigned long flags; 577 578 spin_lock_irqsave(&cleanup_list_lock, flags); 579 list_add(&net->cleanup_list, &cleanup_list); 580 spin_unlock_irqrestore(&cleanup_list_lock, flags); 581 582 queue_work(netns_wq, &net_cleanup_work); 583 } 584 EXPORT_SYMBOL_GPL(__put_net); 585 586 struct net *get_net_ns_by_fd(int fd) 587 { 588 struct file *file; 589 struct ns_common *ns; 590 struct net *net; 591 592 file = proc_ns_fget(fd); 593 if (IS_ERR(file)) 594 return ERR_CAST(file); 595 596 ns = get_proc_ns(file_inode(file)); 597 if (ns->ops == &netns_operations) 598 net = get_net(container_of(ns, struct net, ns)); 599 else 600 net = ERR_PTR(-EINVAL); 601 602 fput(file); 603 return net; 604 } 605 606 #else 607 struct net *get_net_ns_by_fd(int fd) 608 { 609 return ERR_PTR(-EINVAL); 610 } 611 #endif 612 EXPORT_SYMBOL_GPL(get_net_ns_by_fd); 613 614 struct net *get_net_ns_by_pid(pid_t pid) 615 { 616 struct task_struct *tsk; 617 struct net *net; 618 619 /* Lookup the network namespace */ 620 net = ERR_PTR(-ESRCH); 621 rcu_read_lock(); 622 tsk = find_task_by_vpid(pid); 623 if (tsk) { 624 struct nsproxy *nsproxy; 625 task_lock(tsk); 626 nsproxy = tsk->nsproxy; 627 if (nsproxy) 628 net = get_net(nsproxy->net_ns); 629 task_unlock(tsk); 630 } 631 rcu_read_unlock(); 632 return net; 633 } 634 EXPORT_SYMBOL_GPL(get_net_ns_by_pid); 635 636 static __net_init int net_ns_net_init(struct net *net) 637 { 638 #ifdef CONFIG_NET_NS 639 net->ns.ops = &netns_operations; 640 #endif 641 return ns_alloc_inum(&net->ns); 642 } 643 644 static __net_exit void net_ns_net_exit(struct net *net) 645 { 646 ns_free_inum(&net->ns); 647 } 648 649 static struct pernet_operations __net_initdata net_ns_ops = { 650 .init = net_ns_net_init, 651 .exit = net_ns_net_exit, 652 }; 653 654 static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = { 655 [NETNSA_NONE] = { .type = NLA_UNSPEC }, 656 [NETNSA_NSID] = { .type = NLA_S32 }, 657 [NETNSA_PID] = { .type = NLA_U32 }, 658 [NETNSA_FD] = { .type = NLA_U32 }, 659 }; 660 661 static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh, 662 struct netlink_ext_ack *extack) 663 { 664 struct net *net = sock_net(skb->sk); 665 struct nlattr *tb[NETNSA_MAX + 1]; 666 struct nlattr *nla; 667 struct net *peer; 668 int nsid, err; 669 670 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, 671 rtnl_net_policy, extack); 672 if (err < 0) 673 return err; 674 if (!tb[NETNSA_NSID]) { 675 NL_SET_ERR_MSG(extack, "nsid is missing"); 676 return -EINVAL; 677 } 678 nsid = nla_get_s32(tb[NETNSA_NSID]); 679 680 if (tb[NETNSA_PID]) { 681 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 682 nla = tb[NETNSA_PID]; 683 } else if (tb[NETNSA_FD]) { 684 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 685 nla = tb[NETNSA_FD]; 686 } else { 687 NL_SET_ERR_MSG(extack, "Peer netns reference is missing"); 688 return -EINVAL; 689 } 690 if (IS_ERR(peer)) { 691 NL_SET_BAD_ATTR(extack, nla); 692 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid"); 693 return PTR_ERR(peer); 694 } 695 696 spin_lock_bh(&net->nsid_lock); 697 if (__peernet2id(net, peer) >= 0) { 698 spin_unlock_bh(&net->nsid_lock); 699 err = -EEXIST; 700 NL_SET_BAD_ATTR(extack, nla); 701 NL_SET_ERR_MSG(extack, 702 "Peer netns already has a nsid assigned"); 703 goto out; 704 } 705 706 err = alloc_netid(net, peer, nsid); 707 spin_unlock_bh(&net->nsid_lock); 708 if (err >= 0) { 709 rtnl_net_notifyid(net, RTM_NEWNSID, err); 710 err = 0; 711 } else if (err == -ENOSPC && nsid >= 0) { 712 err = -EEXIST; 713 NL_SET_BAD_ATTR(extack, tb[NETNSA_NSID]); 714 NL_SET_ERR_MSG(extack, "The specified nsid is already used"); 715 } 716 out: 717 put_net(peer); 718 return err; 719 } 720 721 static int rtnl_net_get_size(void) 722 { 723 return NLMSG_ALIGN(sizeof(struct rtgenmsg)) 724 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */ 725 ; 726 } 727 728 static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags, 729 int cmd, struct net *net, int nsid) 730 { 731 struct nlmsghdr *nlh; 732 struct rtgenmsg *rth; 733 734 nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rth), flags); 735 if (!nlh) 736 return -EMSGSIZE; 737 738 rth = nlmsg_data(nlh); 739 rth->rtgen_family = AF_UNSPEC; 740 741 if (nla_put_s32(skb, NETNSA_NSID, nsid)) 742 goto nla_put_failure; 743 744 nlmsg_end(skb, nlh); 745 return 0; 746 747 nla_put_failure: 748 nlmsg_cancel(skb, nlh); 749 return -EMSGSIZE; 750 } 751 752 static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh, 753 struct netlink_ext_ack *extack) 754 { 755 struct net *net = sock_net(skb->sk); 756 struct nlattr *tb[NETNSA_MAX + 1]; 757 struct nlattr *nla; 758 struct sk_buff *msg; 759 struct net *peer; 760 int err, id; 761 762 err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX, 763 rtnl_net_policy, extack); 764 if (err < 0) 765 return err; 766 if (tb[NETNSA_PID]) { 767 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID])); 768 nla = tb[NETNSA_PID]; 769 } else if (tb[NETNSA_FD]) { 770 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD])); 771 nla = tb[NETNSA_FD]; 772 } else { 773 NL_SET_ERR_MSG(extack, "Peer netns reference is missing"); 774 return -EINVAL; 775 } 776 777 if (IS_ERR(peer)) { 778 NL_SET_BAD_ATTR(extack, nla); 779 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid"); 780 return PTR_ERR(peer); 781 } 782 783 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 784 if (!msg) { 785 err = -ENOMEM; 786 goto out; 787 } 788 789 id = peernet2id(net, peer); 790 err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0, 791 RTM_NEWNSID, net, id); 792 if (err < 0) 793 goto err_out; 794 795 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid); 796 goto out; 797 798 err_out: 799 nlmsg_free(msg); 800 out: 801 put_net(peer); 802 return err; 803 } 804 805 struct rtnl_net_dump_cb { 806 struct net *net; 807 struct sk_buff *skb; 808 struct netlink_callback *cb; 809 int idx; 810 int s_idx; 811 }; 812 813 static int rtnl_net_dumpid_one(int id, void *peer, void *data) 814 { 815 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data; 816 int ret; 817 818 if (net_cb->idx < net_cb->s_idx) 819 goto cont; 820 821 ret = rtnl_net_fill(net_cb->skb, NETLINK_CB(net_cb->cb->skb).portid, 822 net_cb->cb->nlh->nlmsg_seq, NLM_F_MULTI, 823 RTM_NEWNSID, net_cb->net, id); 824 if (ret < 0) 825 return ret; 826 827 cont: 828 net_cb->idx++; 829 return 0; 830 } 831 832 static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb) 833 { 834 struct net *net = sock_net(skb->sk); 835 struct rtnl_net_dump_cb net_cb = { 836 .net = net, 837 .skb = skb, 838 .cb = cb, 839 .idx = 0, 840 .s_idx = cb->args[0], 841 }; 842 843 spin_lock_bh(&net->nsid_lock); 844 idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb); 845 spin_unlock_bh(&net->nsid_lock); 846 847 cb->args[0] = net_cb.idx; 848 return skb->len; 849 } 850 851 static void rtnl_net_notifyid(struct net *net, int cmd, int id) 852 { 853 struct sk_buff *msg; 854 int err = -ENOMEM; 855 856 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL); 857 if (!msg) 858 goto out; 859 860 err = rtnl_net_fill(msg, 0, 0, 0, cmd, net, id); 861 if (err < 0) 862 goto err_out; 863 864 rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0); 865 return; 866 867 err_out: 868 nlmsg_free(msg); 869 out: 870 rtnl_set_sk_err(net, RTNLGRP_NSID, err); 871 } 872 873 static int __init net_ns_init(void) 874 { 875 struct net_generic *ng; 876 877 #ifdef CONFIG_NET_NS 878 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), 879 SMP_CACHE_BYTES, 880 SLAB_PANIC, NULL); 881 882 /* Create workqueue for cleanup */ 883 netns_wq = create_singlethread_workqueue("netns"); 884 if (!netns_wq) 885 panic("Could not create netns workq"); 886 #endif 887 888 ng = net_alloc_generic(); 889 if (!ng) 890 panic("Could not allocate generic netns"); 891 892 rcu_assign_pointer(init_net.gen, ng); 893 894 down_write(&net_sem); 895 if (setup_net(&init_net, &init_user_ns)) 896 panic("Could not setup the initial network namespace"); 897 898 init_net_initialized = true; 899 up_write(&net_sem); 900 901 register_pernet_subsys(&net_ns_ops); 902 903 rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, 904 RTNL_FLAG_DOIT_UNLOCKED); 905 rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid, 906 RTNL_FLAG_DOIT_UNLOCKED); 907 908 return 0; 909 } 910 911 pure_initcall(net_ns_init); 912 913 #ifdef CONFIG_NET_NS 914 static int __register_pernet_operations(struct list_head *list, 915 struct pernet_operations *ops) 916 { 917 struct net *net; 918 int error; 919 LIST_HEAD(net_exit_list); 920 921 list_add_tail(&ops->list, list); 922 if (ops->init || (ops->id && ops->size)) { 923 for_each_net(net) { 924 error = ops_init(ops, net); 925 if (error) 926 goto out_undo; 927 list_add_tail(&net->exit_list, &net_exit_list); 928 } 929 } 930 return 0; 931 932 out_undo: 933 /* If I have an error cleanup all namespaces I initialized */ 934 list_del(&ops->list); 935 ops_exit_list(ops, &net_exit_list); 936 ops_free_list(ops, &net_exit_list); 937 return error; 938 } 939 940 static void __unregister_pernet_operations(struct pernet_operations *ops) 941 { 942 struct net *net; 943 LIST_HEAD(net_exit_list); 944 945 list_del(&ops->list); 946 for_each_net(net) 947 list_add_tail(&net->exit_list, &net_exit_list); 948 ops_exit_list(ops, &net_exit_list); 949 ops_free_list(ops, &net_exit_list); 950 } 951 952 #else 953 954 static int __register_pernet_operations(struct list_head *list, 955 struct pernet_operations *ops) 956 { 957 if (!init_net_initialized) { 958 list_add_tail(&ops->list, list); 959 return 0; 960 } 961 962 return ops_init(ops, &init_net); 963 } 964 965 static void __unregister_pernet_operations(struct pernet_operations *ops) 966 { 967 if (!init_net_initialized) { 968 list_del(&ops->list); 969 } else { 970 LIST_HEAD(net_exit_list); 971 list_add(&init_net.exit_list, &net_exit_list); 972 ops_exit_list(ops, &net_exit_list); 973 ops_free_list(ops, &net_exit_list); 974 } 975 } 976 977 #endif /* CONFIG_NET_NS */ 978 979 static DEFINE_IDA(net_generic_ids); 980 981 static int register_pernet_operations(struct list_head *list, 982 struct pernet_operations *ops) 983 { 984 int error; 985 986 if (ops->id) { 987 again: 988 error = ida_get_new_above(&net_generic_ids, MIN_PERNET_OPS_ID, ops->id); 989 if (error < 0) { 990 if (error == -EAGAIN) { 991 ida_pre_get(&net_generic_ids, GFP_KERNEL); 992 goto again; 993 } 994 return error; 995 } 996 max_gen_ptrs = max(max_gen_ptrs, *ops->id + 1); 997 } 998 error = __register_pernet_operations(list, ops); 999 if (error) { 1000 rcu_barrier(); 1001 if (ops->id) 1002 ida_remove(&net_generic_ids, *ops->id); 1003 } else if (!ops->async) { 1004 pr_info_once("Pernet operations %ps are sync.\n", ops); 1005 nr_sync_pernet_ops++; 1006 } 1007 1008 return error; 1009 } 1010 1011 static void unregister_pernet_operations(struct pernet_operations *ops) 1012 { 1013 if (!ops->async) 1014 BUG_ON(nr_sync_pernet_ops-- == 0); 1015 __unregister_pernet_operations(ops); 1016 rcu_barrier(); 1017 if (ops->id) 1018 ida_remove(&net_generic_ids, *ops->id); 1019 } 1020 1021 /** 1022 * register_pernet_subsys - register a network namespace subsystem 1023 * @ops: pernet operations structure for the subsystem 1024 * 1025 * Register a subsystem which has init and exit functions 1026 * that are called when network namespaces are created and 1027 * destroyed respectively. 1028 * 1029 * When registered all network namespace init functions are 1030 * called for every existing network namespace. Allowing kernel 1031 * modules to have a race free view of the set of network namespaces. 1032 * 1033 * When a new network namespace is created all of the init 1034 * methods are called in the order in which they were registered. 1035 * 1036 * When a network namespace is destroyed all of the exit methods 1037 * are called in the reverse of the order with which they were 1038 * registered. 1039 */ 1040 int register_pernet_subsys(struct pernet_operations *ops) 1041 { 1042 int error; 1043 down_write(&net_sem); 1044 error = register_pernet_operations(first_device, ops); 1045 up_write(&net_sem); 1046 return error; 1047 } 1048 EXPORT_SYMBOL_GPL(register_pernet_subsys); 1049 1050 /** 1051 * unregister_pernet_subsys - unregister a network namespace subsystem 1052 * @ops: pernet operations structure to manipulate 1053 * 1054 * Remove the pernet operations structure from the list to be 1055 * used when network namespaces are created or destroyed. In 1056 * addition run the exit method for all existing network 1057 * namespaces. 1058 */ 1059 void unregister_pernet_subsys(struct pernet_operations *ops) 1060 { 1061 down_write(&net_sem); 1062 unregister_pernet_operations(ops); 1063 up_write(&net_sem); 1064 } 1065 EXPORT_SYMBOL_GPL(unregister_pernet_subsys); 1066 1067 /** 1068 * register_pernet_device - register a network namespace device 1069 * @ops: pernet operations structure for the subsystem 1070 * 1071 * Register a device which has init and exit functions 1072 * that are called when network namespaces are created and 1073 * destroyed respectively. 1074 * 1075 * When registered all network namespace init functions are 1076 * called for every existing network namespace. Allowing kernel 1077 * modules to have a race free view of the set of network namespaces. 1078 * 1079 * When a new network namespace is created all of the init 1080 * methods are called in the order in which they were registered. 1081 * 1082 * When a network namespace is destroyed all of the exit methods 1083 * are called in the reverse of the order with which they were 1084 * registered. 1085 */ 1086 int register_pernet_device(struct pernet_operations *ops) 1087 { 1088 int error; 1089 down_write(&net_sem); 1090 error = register_pernet_operations(&pernet_list, ops); 1091 if (!error && (first_device == &pernet_list)) 1092 first_device = &ops->list; 1093 up_write(&net_sem); 1094 return error; 1095 } 1096 EXPORT_SYMBOL_GPL(register_pernet_device); 1097 1098 /** 1099 * unregister_pernet_device - unregister a network namespace netdevice 1100 * @ops: pernet operations structure to manipulate 1101 * 1102 * Remove the pernet operations structure from the list to be 1103 * used when network namespaces are created or destroyed. In 1104 * addition run the exit method for all existing network 1105 * namespaces. 1106 */ 1107 void unregister_pernet_device(struct pernet_operations *ops) 1108 { 1109 down_write(&net_sem); 1110 if (&ops->list == first_device) 1111 first_device = first_device->next; 1112 unregister_pernet_operations(ops); 1113 up_write(&net_sem); 1114 } 1115 EXPORT_SYMBOL_GPL(unregister_pernet_device); 1116 1117 #ifdef CONFIG_NET_NS 1118 static struct ns_common *netns_get(struct task_struct *task) 1119 { 1120 struct net *net = NULL; 1121 struct nsproxy *nsproxy; 1122 1123 task_lock(task); 1124 nsproxy = task->nsproxy; 1125 if (nsproxy) 1126 net = get_net(nsproxy->net_ns); 1127 task_unlock(task); 1128 1129 return net ? &net->ns : NULL; 1130 } 1131 1132 static inline struct net *to_net_ns(struct ns_common *ns) 1133 { 1134 return container_of(ns, struct net, ns); 1135 } 1136 1137 static void netns_put(struct ns_common *ns) 1138 { 1139 put_net(to_net_ns(ns)); 1140 } 1141 1142 static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns) 1143 { 1144 struct net *net = to_net_ns(ns); 1145 1146 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) || 1147 !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) 1148 return -EPERM; 1149 1150 put_net(nsproxy->net_ns); 1151 nsproxy->net_ns = get_net(net); 1152 return 0; 1153 } 1154 1155 static struct user_namespace *netns_owner(struct ns_common *ns) 1156 { 1157 return to_net_ns(ns)->user_ns; 1158 } 1159 1160 const struct proc_ns_operations netns_operations = { 1161 .name = "net", 1162 .type = CLONE_NEWNET, 1163 .get = netns_get, 1164 .put = netns_put, 1165 .install = netns_install, 1166 .owner = netns_owner, 1167 }; 1168 #endif 1169