1 // SPDX-License-Identifier: GPL-2.0-only
2 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
3
4 #include <linux/workqueue.h>
5 #include <linux/rtnetlink.h>
6 #include <linux/cache.h>
7 #include <linux/slab.h>
8 #include <linux/list.h>
9 #include <linux/delay.h>
10 #include <linux/sched.h>
11 #include <linux/idr.h>
12 #include <linux/rculist.h>
13 #include <linux/nsproxy.h>
14 #include <linux/fs.h>
15 #include <linux/proc_ns.h>
16 #include <linux/file.h>
17 #include <linux/export.h>
18 #include <linux/user_namespace.h>
19 #include <linux/net_namespace.h>
20 #include <linux/sched/task.h>
21 #include <linux/uidgid.h>
22 #include <linux/cookie.h>
23 #include <linux/proc_fs.h>
24
25 #include <net/sock.h>
26 #include <net/netlink.h>
27 #include <net/net_namespace.h>
28 #include <net/netns/generic.h>
29
30 /*
31 * Our network namespace constructor/destructor lists
32 */
33
34 static LIST_HEAD(pernet_list);
35 static struct list_head *first_device = &pernet_list;
36
37 LIST_HEAD(net_namespace_list);
38 EXPORT_SYMBOL_GPL(net_namespace_list);
39
40 /* Protects net_namespace_list. Nests iside rtnl_lock() */
41 DECLARE_RWSEM(net_rwsem);
42 EXPORT_SYMBOL_GPL(net_rwsem);
43
44 #ifdef CONFIG_KEYS
45 static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) };
46 #endif
47
48 struct net init_net;
49 EXPORT_SYMBOL(init_net);
50
51 static bool init_net_initialized;
52 /*
53 * pernet_ops_rwsem: protects: pernet_list, net_generic_ids,
54 * init_net_initialized and first_device pointer.
55 * This is internal net namespace object. Please, don't use it
56 * outside.
57 */
58 DECLARE_RWSEM(pernet_ops_rwsem);
59 EXPORT_SYMBOL_GPL(pernet_ops_rwsem);
60
61 #define MIN_PERNET_OPS_ID \
62 ((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *))
63
64 #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
65
66 static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
67
68 DEFINE_COOKIE(net_cookie);
69
net_alloc_generic(void)70 static struct net_generic *net_alloc_generic(void)
71 {
72 unsigned int gen_ptrs = READ_ONCE(max_gen_ptrs);
73 unsigned int generic_size;
74 struct net_generic *ng;
75
76 generic_size = offsetof(struct net_generic, ptr[gen_ptrs]);
77
78 ng = kzalloc(generic_size, GFP_KERNEL);
79 if (ng)
80 ng->s.len = gen_ptrs;
81
82 return ng;
83 }
84
net_assign_generic(struct net * net,unsigned int id,void * data)85 static int net_assign_generic(struct net *net, unsigned int id, void *data)
86 {
87 struct net_generic *ng, *old_ng;
88
89 BUG_ON(id < MIN_PERNET_OPS_ID);
90
91 old_ng = rcu_dereference_protected(net->gen,
92 lockdep_is_held(&pernet_ops_rwsem));
93 if (old_ng->s.len > id) {
94 old_ng->ptr[id] = data;
95 return 0;
96 }
97
98 ng = net_alloc_generic();
99 if (!ng)
100 return -ENOMEM;
101
102 /*
103 * Some synchronisation notes:
104 *
105 * The net_generic explores the net->gen array inside rcu
106 * read section. Besides once set the net->gen->ptr[x]
107 * pointer never changes (see rules in netns/generic.h).
108 *
109 * That said, we simply duplicate this array and schedule
110 * the old copy for kfree after a grace period.
111 */
112
113 memcpy(&ng->ptr[MIN_PERNET_OPS_ID], &old_ng->ptr[MIN_PERNET_OPS_ID],
114 (old_ng->s.len - MIN_PERNET_OPS_ID) * sizeof(void *));
115 ng->ptr[id] = data;
116
117 rcu_assign_pointer(net->gen, ng);
118 kfree_rcu(old_ng, s.rcu);
119 return 0;
120 }
121
ops_init(const struct pernet_operations * ops,struct net * net)122 static int ops_init(const struct pernet_operations *ops, struct net *net)
123 {
124 struct net_generic *ng;
125 int err = -ENOMEM;
126 void *data = NULL;
127
128 if (ops->id && ops->size) {
129 data = kzalloc(ops->size, GFP_KERNEL);
130 if (!data)
131 goto out;
132
133 err = net_assign_generic(net, *ops->id, data);
134 if (err)
135 goto cleanup;
136 }
137 err = 0;
138 if (ops->init)
139 err = ops->init(net);
140 if (!err)
141 return 0;
142
143 if (ops->id && ops->size) {
144 ng = rcu_dereference_protected(net->gen,
145 lockdep_is_held(&pernet_ops_rwsem));
146 ng->ptr[*ops->id] = NULL;
147 }
148
149 cleanup:
150 kfree(data);
151
152 out:
153 return err;
154 }
155
ops_pre_exit_list(const struct pernet_operations * ops,struct list_head * net_exit_list)156 static void ops_pre_exit_list(const struct pernet_operations *ops,
157 struct list_head *net_exit_list)
158 {
159 struct net *net;
160
161 if (ops->pre_exit) {
162 list_for_each_entry(net, net_exit_list, exit_list)
163 ops->pre_exit(net);
164 }
165 }
166
ops_exit_list(const struct pernet_operations * ops,struct list_head * net_exit_list)167 static void ops_exit_list(const struct pernet_operations *ops,
168 struct list_head *net_exit_list)
169 {
170 struct net *net;
171 if (ops->exit) {
172 list_for_each_entry(net, net_exit_list, exit_list) {
173 ops->exit(net);
174 cond_resched();
175 }
176 }
177 if (ops->exit_batch)
178 ops->exit_batch(net_exit_list);
179 }
180
ops_free_list(const struct pernet_operations * ops,struct list_head * net_exit_list)181 static void ops_free_list(const struct pernet_operations *ops,
182 struct list_head *net_exit_list)
183 {
184 struct net *net;
185 if (ops->size && ops->id) {
186 list_for_each_entry(net, net_exit_list, exit_list)
187 kfree(net_generic(net, *ops->id));
188 }
189 }
190
191 /* should be called with nsid_lock held */
alloc_netid(struct net * net,struct net * peer,int reqid)192 static int alloc_netid(struct net *net, struct net *peer, int reqid)
193 {
194 int min = 0, max = 0;
195
196 if (reqid >= 0) {
197 min = reqid;
198 max = reqid + 1;
199 }
200
201 return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC);
202 }
203
204 /* This function is used by idr_for_each(). If net is equal to peer, the
205 * function returns the id so that idr_for_each() stops. Because we cannot
206 * returns the id 0 (idr_for_each() will not stop), we return the magic value
207 * NET_ID_ZERO (-1) for it.
208 */
209 #define NET_ID_ZERO -1
net_eq_idr(int id,void * net,void * peer)210 static int net_eq_idr(int id, void *net, void *peer)
211 {
212 if (net_eq(net, peer))
213 return id ? : NET_ID_ZERO;
214 return 0;
215 }
216
217 /* Must be called from RCU-critical section or with nsid_lock held */
__peernet2id(const struct net * net,struct net * peer)218 static int __peernet2id(const struct net *net, struct net *peer)
219 {
220 int id = idr_for_each(&net->netns_ids, net_eq_idr, peer);
221
222 /* Magic value for id 0. */
223 if (id == NET_ID_ZERO)
224 return 0;
225 if (id > 0)
226 return id;
227
228 return NETNSA_NSID_NOT_ASSIGNED;
229 }
230
231 static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
232 struct nlmsghdr *nlh, gfp_t gfp);
233 /* This function returns the id of a peer netns. If no id is assigned, one will
234 * be allocated and returned.
235 */
peernet2id_alloc(struct net * net,struct net * peer,gfp_t gfp)236 int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp)
237 {
238 int id;
239
240 if (refcount_read(&net->ns.count) == 0)
241 return NETNSA_NSID_NOT_ASSIGNED;
242
243 spin_lock_bh(&net->nsid_lock);
244 id = __peernet2id(net, peer);
245 if (id >= 0) {
246 spin_unlock_bh(&net->nsid_lock);
247 return id;
248 }
249
250 /* When peer is obtained from RCU lists, we may race with
251 * its cleanup. Check whether it's alive, and this guarantees
252 * we never hash a peer back to net->netns_ids, after it has
253 * just been idr_remove()'d from there in cleanup_net().
254 */
255 if (!maybe_get_net(peer)) {
256 spin_unlock_bh(&net->nsid_lock);
257 return NETNSA_NSID_NOT_ASSIGNED;
258 }
259
260 id = alloc_netid(net, peer, -1);
261 spin_unlock_bh(&net->nsid_lock);
262
263 put_net(peer);
264 if (id < 0)
265 return NETNSA_NSID_NOT_ASSIGNED;
266
267 rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL, gfp);
268
269 return id;
270 }
271 EXPORT_SYMBOL_GPL(peernet2id_alloc);
272
273 /* This function returns, if assigned, the id of a peer netns. */
peernet2id(const struct net * net,struct net * peer)274 int peernet2id(const struct net *net, struct net *peer)
275 {
276 int id;
277
278 rcu_read_lock();
279 id = __peernet2id(net, peer);
280 rcu_read_unlock();
281
282 return id;
283 }
284 EXPORT_SYMBOL(peernet2id);
285
286 /* This function returns true is the peer netns has an id assigned into the
287 * current netns.
288 */
peernet_has_id(const struct net * net,struct net * peer)289 bool peernet_has_id(const struct net *net, struct net *peer)
290 {
291 return peernet2id(net, peer) >= 0;
292 }
293
get_net_ns_by_id(const struct net * net,int id)294 struct net *get_net_ns_by_id(const struct net *net, int id)
295 {
296 struct net *peer;
297
298 if (id < 0)
299 return NULL;
300
301 rcu_read_lock();
302 peer = idr_find(&net->netns_ids, id);
303 if (peer)
304 peer = maybe_get_net(peer);
305 rcu_read_unlock();
306
307 return peer;
308 }
309 EXPORT_SYMBOL_GPL(get_net_ns_by_id);
310
311 /* init code that must occur even if setup_net() is not called. */
preinit_net(struct net * net)312 static __net_init void preinit_net(struct net *net)
313 {
314 ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net notrefcnt");
315 }
316
317 /*
318 * setup_net runs the initializers for the network namespace object.
319 */
setup_net(struct net * net,struct user_namespace * user_ns)320 static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
321 {
322 /* Must be called with pernet_ops_rwsem held */
323 const struct pernet_operations *ops, *saved_ops;
324 LIST_HEAD(net_exit_list);
325 LIST_HEAD(dev_kill_list);
326 int error = 0;
327
328 refcount_set(&net->ns.count, 1);
329 ref_tracker_dir_init(&net->refcnt_tracker, 128, "net refcnt");
330
331 refcount_set(&net->passive, 1);
332 get_random_bytes(&net->hash_mix, sizeof(u32));
333 preempt_disable();
334 net->net_cookie = gen_cookie_next(&net_cookie);
335 preempt_enable();
336 net->dev_base_seq = 1;
337 net->user_ns = user_ns;
338 idr_init(&net->netns_ids);
339 spin_lock_init(&net->nsid_lock);
340 mutex_init(&net->ipv4.ra_mutex);
341
342 list_for_each_entry(ops, &pernet_list, list) {
343 error = ops_init(ops, net);
344 if (error < 0)
345 goto out_undo;
346 }
347 down_write(&net_rwsem);
348 list_add_tail_rcu(&net->list, &net_namespace_list);
349 up_write(&net_rwsem);
350 out:
351 return error;
352
353 out_undo:
354 /* Walk through the list backwards calling the exit functions
355 * for the pernet modules whose init functions did not fail.
356 */
357 list_add(&net->exit_list, &net_exit_list);
358 saved_ops = ops;
359 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
360 ops_pre_exit_list(ops, &net_exit_list);
361
362 synchronize_rcu();
363
364 ops = saved_ops;
365 rtnl_lock();
366 list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
367 if (ops->exit_batch_rtnl)
368 ops->exit_batch_rtnl(&net_exit_list, &dev_kill_list);
369 }
370 unregister_netdevice_many(&dev_kill_list);
371 rtnl_unlock();
372
373 ops = saved_ops;
374 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
375 ops_exit_list(ops, &net_exit_list);
376
377 ops = saved_ops;
378 list_for_each_entry_continue_reverse(ops, &pernet_list, list)
379 ops_free_list(ops, &net_exit_list);
380
381 rcu_barrier();
382 goto out;
383 }
384
net_defaults_init_net(struct net * net)385 static int __net_init net_defaults_init_net(struct net *net)
386 {
387 net->core.sysctl_somaxconn = SOMAXCONN;
388 /* Limits per socket sk_omem_alloc usage.
389 * TCP zerocopy regular usage needs 128 KB.
390 */
391 net->core.sysctl_optmem_max = 128 * 1024;
392 net->core.sysctl_txrehash = SOCK_TXREHASH_ENABLED;
393
394 return 0;
395 }
396
397 static struct pernet_operations net_defaults_ops = {
398 .init = net_defaults_init_net,
399 };
400
net_defaults_init(void)401 static __init int net_defaults_init(void)
402 {
403 if (register_pernet_subsys(&net_defaults_ops))
404 panic("Cannot initialize net default settings");
405
406 return 0;
407 }
408
409 core_initcall(net_defaults_init);
410
411 #ifdef CONFIG_NET_NS
inc_net_namespaces(struct user_namespace * ns)412 static struct ucounts *inc_net_namespaces(struct user_namespace *ns)
413 {
414 return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES);
415 }
416
dec_net_namespaces(struct ucounts * ucounts)417 static void dec_net_namespaces(struct ucounts *ucounts)
418 {
419 dec_ucount(ucounts, UCOUNT_NET_NAMESPACES);
420 }
421
422 static struct kmem_cache *net_cachep __ro_after_init;
423 static struct workqueue_struct *netns_wq;
424
net_alloc(void)425 static struct net *net_alloc(void)
426 {
427 struct net *net = NULL;
428 struct net_generic *ng;
429
430 ng = net_alloc_generic();
431 if (!ng)
432 goto out;
433
434 net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
435 if (!net)
436 goto out_free;
437
438 #ifdef CONFIG_KEYS
439 net->key_domain = kzalloc(sizeof(struct key_tag), GFP_KERNEL);
440 if (!net->key_domain)
441 goto out_free_2;
442 refcount_set(&net->key_domain->usage, 1);
443 #endif
444
445 rcu_assign_pointer(net->gen, ng);
446 out:
447 return net;
448
449 #ifdef CONFIG_KEYS
450 out_free_2:
451 kmem_cache_free(net_cachep, net);
452 net = NULL;
453 #endif
454 out_free:
455 kfree(ng);
456 goto out;
457 }
458
net_free(struct net * net)459 static void net_free(struct net *net)
460 {
461 if (refcount_dec_and_test(&net->passive)) {
462 kfree(rcu_access_pointer(net->gen));
463
464 /* There should not be any trackers left there. */
465 ref_tracker_dir_exit(&net->notrefcnt_tracker);
466
467 kmem_cache_free(net_cachep, net);
468 }
469 }
470
net_drop_ns(void * p)471 void net_drop_ns(void *p)
472 {
473 struct net *net = (struct net *)p;
474
475 if (net)
476 net_free(net);
477 }
478
copy_net_ns(unsigned long flags,struct user_namespace * user_ns,struct net * old_net)479 struct net *copy_net_ns(unsigned long flags,
480 struct user_namespace *user_ns, struct net *old_net)
481 {
482 struct ucounts *ucounts;
483 struct net *net;
484 int rv;
485
486 if (!(flags & CLONE_NEWNET))
487 return get_net(old_net);
488
489 ucounts = inc_net_namespaces(user_ns);
490 if (!ucounts)
491 return ERR_PTR(-ENOSPC);
492
493 net = net_alloc();
494 if (!net) {
495 rv = -ENOMEM;
496 goto dec_ucounts;
497 }
498
499 preinit_net(net);
500 refcount_set(&net->passive, 1);
501 net->ucounts = ucounts;
502 get_user_ns(user_ns);
503
504 rv = down_read_killable(&pernet_ops_rwsem);
505 if (rv < 0)
506 goto put_userns;
507
508 rv = setup_net(net, user_ns);
509
510 up_read(&pernet_ops_rwsem);
511
512 if (rv < 0) {
513 put_userns:
514 #ifdef CONFIG_KEYS
515 key_remove_domain(net->key_domain);
516 #endif
517 put_user_ns(user_ns);
518 net_free(net);
519 dec_ucounts:
520 dec_net_namespaces(ucounts);
521 return ERR_PTR(rv);
522 }
523 return net;
524 }
525
526 /**
527 * net_ns_get_ownership - get sysfs ownership data for @net
528 * @net: network namespace in question (can be NULL)
529 * @uid: kernel user ID for sysfs objects
530 * @gid: kernel group ID for sysfs objects
531 *
532 * Returns the uid/gid pair of root in the user namespace associated with the
533 * given network namespace.
534 */
net_ns_get_ownership(const struct net * net,kuid_t * uid,kgid_t * gid)535 void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid)
536 {
537 if (net) {
538 kuid_t ns_root_uid = make_kuid(net->user_ns, 0);
539 kgid_t ns_root_gid = make_kgid(net->user_ns, 0);
540
541 if (uid_valid(ns_root_uid))
542 *uid = ns_root_uid;
543
544 if (gid_valid(ns_root_gid))
545 *gid = ns_root_gid;
546 } else {
547 *uid = GLOBAL_ROOT_UID;
548 *gid = GLOBAL_ROOT_GID;
549 }
550 }
551 EXPORT_SYMBOL_GPL(net_ns_get_ownership);
552
unhash_nsid(struct net * net,struct net * last)553 static void unhash_nsid(struct net *net, struct net *last)
554 {
555 struct net *tmp;
556 /* This function is only called from cleanup_net() work,
557 * and this work is the only process, that may delete
558 * a net from net_namespace_list. So, when the below
559 * is executing, the list may only grow. Thus, we do not
560 * use for_each_net_rcu() or net_rwsem.
561 */
562 for_each_net(tmp) {
563 int id;
564
565 spin_lock_bh(&tmp->nsid_lock);
566 id = __peernet2id(tmp, net);
567 if (id >= 0)
568 idr_remove(&tmp->netns_ids, id);
569 spin_unlock_bh(&tmp->nsid_lock);
570 if (id >= 0)
571 rtnl_net_notifyid(tmp, RTM_DELNSID, id, 0, NULL,
572 GFP_KERNEL);
573 if (tmp == last)
574 break;
575 }
576 spin_lock_bh(&net->nsid_lock);
577 idr_destroy(&net->netns_ids);
578 spin_unlock_bh(&net->nsid_lock);
579 }
580
581 static LLIST_HEAD(cleanup_list);
582
cleanup_net(struct work_struct * work)583 static void cleanup_net(struct work_struct *work)
584 {
585 const struct pernet_operations *ops;
586 struct net *net, *tmp, *last;
587 struct llist_node *net_kill_list;
588 LIST_HEAD(net_exit_list);
589 LIST_HEAD(dev_kill_list);
590
591 /* Atomically snapshot the list of namespaces to cleanup */
592 net_kill_list = llist_del_all(&cleanup_list);
593
594 down_read(&pernet_ops_rwsem);
595
596 /* Don't let anyone else find us. */
597 down_write(&net_rwsem);
598 llist_for_each_entry(net, net_kill_list, cleanup_list)
599 list_del_rcu(&net->list);
600 /* Cache last net. After we unlock rtnl, no one new net
601 * added to net_namespace_list can assign nsid pointer
602 * to a net from net_kill_list (see peernet2id_alloc()).
603 * So, we skip them in unhash_nsid().
604 *
605 * Note, that unhash_nsid() does not delete nsid links
606 * between net_kill_list's nets, as they've already
607 * deleted from net_namespace_list. But, this would be
608 * useless anyway, as netns_ids are destroyed there.
609 */
610 last = list_last_entry(&net_namespace_list, struct net, list);
611 up_write(&net_rwsem);
612
613 llist_for_each_entry(net, net_kill_list, cleanup_list) {
614 unhash_nsid(net, last);
615 list_add_tail(&net->exit_list, &net_exit_list);
616 }
617
618 /* Run all of the network namespace pre_exit methods */
619 list_for_each_entry_reverse(ops, &pernet_list, list)
620 ops_pre_exit_list(ops, &net_exit_list);
621
622 /*
623 * Another CPU might be rcu-iterating the list, wait for it.
624 * This needs to be before calling the exit() notifiers, so
625 * the rcu_barrier() below isn't sufficient alone.
626 * Also the pre_exit() and exit() methods need this barrier.
627 */
628 synchronize_rcu_expedited();
629
630 rtnl_lock();
631 list_for_each_entry_reverse(ops, &pernet_list, list) {
632 if (ops->exit_batch_rtnl)
633 ops->exit_batch_rtnl(&net_exit_list, &dev_kill_list);
634 }
635 unregister_netdevice_many(&dev_kill_list);
636 rtnl_unlock();
637
638 /* Run all of the network namespace exit methods */
639 list_for_each_entry_reverse(ops, &pernet_list, list)
640 ops_exit_list(ops, &net_exit_list);
641
642 /* Free the net generic variables */
643 list_for_each_entry_reverse(ops, &pernet_list, list)
644 ops_free_list(ops, &net_exit_list);
645
646 up_read(&pernet_ops_rwsem);
647
648 /* Ensure there are no outstanding rcu callbacks using this
649 * network namespace.
650 */
651 rcu_barrier();
652
653 /* Finally it is safe to free my network namespace structure */
654 list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
655 list_del_init(&net->exit_list);
656 dec_net_namespaces(net->ucounts);
657 #ifdef CONFIG_KEYS
658 key_remove_domain(net->key_domain);
659 #endif
660 put_user_ns(net->user_ns);
661 net_free(net);
662 }
663 }
664
665 /**
666 * net_ns_barrier - wait until concurrent net_cleanup_work is done
667 *
668 * cleanup_net runs from work queue and will first remove namespaces
669 * from the global list, then run net exit functions.
670 *
671 * Call this in module exit path to make sure that all netns
672 * ->exit ops have been invoked before the function is removed.
673 */
net_ns_barrier(void)674 void net_ns_barrier(void)
675 {
676 down_write(&pernet_ops_rwsem);
677 up_write(&pernet_ops_rwsem);
678 }
679 EXPORT_SYMBOL(net_ns_barrier);
680
681 static DECLARE_WORK(net_cleanup_work, cleanup_net);
682
__put_net(struct net * net)683 void __put_net(struct net *net)
684 {
685 ref_tracker_dir_exit(&net->refcnt_tracker);
686 /* Cleanup the network namespace in process context */
687 if (llist_add(&net->cleanup_list, &cleanup_list))
688 queue_work(netns_wq, &net_cleanup_work);
689 }
690 EXPORT_SYMBOL_GPL(__put_net);
691
692 /**
693 * get_net_ns - increment the refcount of the network namespace
694 * @ns: common namespace (net)
695 *
696 * Returns the net's common namespace.
697 */
get_net_ns(struct ns_common * ns)698 struct ns_common *get_net_ns(struct ns_common *ns)
699 {
700 return &get_net(container_of(ns, struct net, ns))->ns;
701 }
702 EXPORT_SYMBOL_GPL(get_net_ns);
703
get_net_ns_by_fd(int fd)704 struct net *get_net_ns_by_fd(int fd)
705 {
706 struct fd f = fdget(fd);
707 struct net *net = ERR_PTR(-EINVAL);
708
709 if (!f.file)
710 return ERR_PTR(-EBADF);
711
712 if (proc_ns_file(f.file)) {
713 struct ns_common *ns = get_proc_ns(file_inode(f.file));
714 if (ns->ops == &netns_operations)
715 net = get_net(container_of(ns, struct net, ns));
716 }
717 fdput(f);
718
719 return net;
720 }
721 EXPORT_SYMBOL_GPL(get_net_ns_by_fd);
722 #endif
723
get_net_ns_by_pid(pid_t pid)724 struct net *get_net_ns_by_pid(pid_t pid)
725 {
726 struct task_struct *tsk;
727 struct net *net;
728
729 /* Lookup the network namespace */
730 net = ERR_PTR(-ESRCH);
731 rcu_read_lock();
732 tsk = find_task_by_vpid(pid);
733 if (tsk) {
734 struct nsproxy *nsproxy;
735 task_lock(tsk);
736 nsproxy = tsk->nsproxy;
737 if (nsproxy)
738 net = get_net(nsproxy->net_ns);
739 task_unlock(tsk);
740 }
741 rcu_read_unlock();
742 return net;
743 }
744 EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
745
net_ns_net_init(struct net * net)746 static __net_init int net_ns_net_init(struct net *net)
747 {
748 #ifdef CONFIG_NET_NS
749 net->ns.ops = &netns_operations;
750 #endif
751 return ns_alloc_inum(&net->ns);
752 }
753
net_ns_net_exit(struct net * net)754 static __net_exit void net_ns_net_exit(struct net *net)
755 {
756 ns_free_inum(&net->ns);
757 }
758
759 static struct pernet_operations __net_initdata net_ns_ops = {
760 .init = net_ns_net_init,
761 .exit = net_ns_net_exit,
762 };
763
764 static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = {
765 [NETNSA_NONE] = { .type = NLA_UNSPEC },
766 [NETNSA_NSID] = { .type = NLA_S32 },
767 [NETNSA_PID] = { .type = NLA_U32 },
768 [NETNSA_FD] = { .type = NLA_U32 },
769 [NETNSA_TARGET_NSID] = { .type = NLA_S32 },
770 };
771
rtnl_net_newid(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)772 static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh,
773 struct netlink_ext_ack *extack)
774 {
775 struct net *net = sock_net(skb->sk);
776 struct nlattr *tb[NETNSA_MAX + 1];
777 struct nlattr *nla;
778 struct net *peer;
779 int nsid, err;
780
781 err = nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg), tb,
782 NETNSA_MAX, rtnl_net_policy, extack);
783 if (err < 0)
784 return err;
785 if (!tb[NETNSA_NSID]) {
786 NL_SET_ERR_MSG(extack, "nsid is missing");
787 return -EINVAL;
788 }
789 nsid = nla_get_s32(tb[NETNSA_NSID]);
790
791 if (tb[NETNSA_PID]) {
792 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
793 nla = tb[NETNSA_PID];
794 } else if (tb[NETNSA_FD]) {
795 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
796 nla = tb[NETNSA_FD];
797 } else {
798 NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
799 return -EINVAL;
800 }
801 if (IS_ERR(peer)) {
802 NL_SET_BAD_ATTR(extack, nla);
803 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
804 return PTR_ERR(peer);
805 }
806
807 spin_lock_bh(&net->nsid_lock);
808 if (__peernet2id(net, peer) >= 0) {
809 spin_unlock_bh(&net->nsid_lock);
810 err = -EEXIST;
811 NL_SET_BAD_ATTR(extack, nla);
812 NL_SET_ERR_MSG(extack,
813 "Peer netns already has a nsid assigned");
814 goto out;
815 }
816
817 err = alloc_netid(net, peer, nsid);
818 spin_unlock_bh(&net->nsid_lock);
819 if (err >= 0) {
820 rtnl_net_notifyid(net, RTM_NEWNSID, err, NETLINK_CB(skb).portid,
821 nlh, GFP_KERNEL);
822 err = 0;
823 } else if (err == -ENOSPC && nsid >= 0) {
824 err = -EEXIST;
825 NL_SET_BAD_ATTR(extack, tb[NETNSA_NSID]);
826 NL_SET_ERR_MSG(extack, "The specified nsid is already used");
827 }
828 out:
829 put_net(peer);
830 return err;
831 }
832
rtnl_net_get_size(void)833 static int rtnl_net_get_size(void)
834 {
835 return NLMSG_ALIGN(sizeof(struct rtgenmsg))
836 + nla_total_size(sizeof(s32)) /* NETNSA_NSID */
837 + nla_total_size(sizeof(s32)) /* NETNSA_CURRENT_NSID */
838 ;
839 }
840
841 struct net_fill_args {
842 u32 portid;
843 u32 seq;
844 int flags;
845 int cmd;
846 int nsid;
847 bool add_ref;
848 int ref_nsid;
849 };
850
rtnl_net_fill(struct sk_buff * skb,struct net_fill_args * args)851 static int rtnl_net_fill(struct sk_buff *skb, struct net_fill_args *args)
852 {
853 struct nlmsghdr *nlh;
854 struct rtgenmsg *rth;
855
856 nlh = nlmsg_put(skb, args->portid, args->seq, args->cmd, sizeof(*rth),
857 args->flags);
858 if (!nlh)
859 return -EMSGSIZE;
860
861 rth = nlmsg_data(nlh);
862 rth->rtgen_family = AF_UNSPEC;
863
864 if (nla_put_s32(skb, NETNSA_NSID, args->nsid))
865 goto nla_put_failure;
866
867 if (args->add_ref &&
868 nla_put_s32(skb, NETNSA_CURRENT_NSID, args->ref_nsid))
869 goto nla_put_failure;
870
871 nlmsg_end(skb, nlh);
872 return 0;
873
874 nla_put_failure:
875 nlmsg_cancel(skb, nlh);
876 return -EMSGSIZE;
877 }
878
rtnl_net_valid_getid_req(struct sk_buff * skb,const struct nlmsghdr * nlh,struct nlattr ** tb,struct netlink_ext_ack * extack)879 static int rtnl_net_valid_getid_req(struct sk_buff *skb,
880 const struct nlmsghdr *nlh,
881 struct nlattr **tb,
882 struct netlink_ext_ack *extack)
883 {
884 int i, err;
885
886 if (!netlink_strict_get_check(skb))
887 return nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg),
888 tb, NETNSA_MAX, rtnl_net_policy,
889 extack);
890
891 err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb,
892 NETNSA_MAX, rtnl_net_policy,
893 extack);
894 if (err)
895 return err;
896
897 for (i = 0; i <= NETNSA_MAX; i++) {
898 if (!tb[i])
899 continue;
900
901 switch (i) {
902 case NETNSA_PID:
903 case NETNSA_FD:
904 case NETNSA_NSID:
905 case NETNSA_TARGET_NSID:
906 break;
907 default:
908 NL_SET_ERR_MSG(extack, "Unsupported attribute in peer netns getid request");
909 return -EINVAL;
910 }
911 }
912
913 return 0;
914 }
915
rtnl_net_getid(struct sk_buff * skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)916 static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh,
917 struct netlink_ext_ack *extack)
918 {
919 struct net *net = sock_net(skb->sk);
920 struct nlattr *tb[NETNSA_MAX + 1];
921 struct net_fill_args fillargs = {
922 .portid = NETLINK_CB(skb).portid,
923 .seq = nlh->nlmsg_seq,
924 .cmd = RTM_NEWNSID,
925 };
926 struct net *peer, *target = net;
927 struct nlattr *nla;
928 struct sk_buff *msg;
929 int err;
930
931 err = rtnl_net_valid_getid_req(skb, nlh, tb, extack);
932 if (err < 0)
933 return err;
934 if (tb[NETNSA_PID]) {
935 peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
936 nla = tb[NETNSA_PID];
937 } else if (tb[NETNSA_FD]) {
938 peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
939 nla = tb[NETNSA_FD];
940 } else if (tb[NETNSA_NSID]) {
941 peer = get_net_ns_by_id(net, nla_get_s32(tb[NETNSA_NSID]));
942 if (!peer)
943 peer = ERR_PTR(-ENOENT);
944 nla = tb[NETNSA_NSID];
945 } else {
946 NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
947 return -EINVAL;
948 }
949
950 if (IS_ERR(peer)) {
951 NL_SET_BAD_ATTR(extack, nla);
952 NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
953 return PTR_ERR(peer);
954 }
955
956 if (tb[NETNSA_TARGET_NSID]) {
957 int id = nla_get_s32(tb[NETNSA_TARGET_NSID]);
958
959 target = rtnl_get_net_ns_capable(NETLINK_CB(skb).sk, id);
960 if (IS_ERR(target)) {
961 NL_SET_BAD_ATTR(extack, tb[NETNSA_TARGET_NSID]);
962 NL_SET_ERR_MSG(extack,
963 "Target netns reference is invalid");
964 err = PTR_ERR(target);
965 goto out;
966 }
967 fillargs.add_ref = true;
968 fillargs.ref_nsid = peernet2id(net, peer);
969 }
970
971 msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
972 if (!msg) {
973 err = -ENOMEM;
974 goto out;
975 }
976
977 fillargs.nsid = peernet2id(target, peer);
978 err = rtnl_net_fill(msg, &fillargs);
979 if (err < 0)
980 goto err_out;
981
982 err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid);
983 goto out;
984
985 err_out:
986 nlmsg_free(msg);
987 out:
988 if (fillargs.add_ref)
989 put_net(target);
990 put_net(peer);
991 return err;
992 }
993
994 struct rtnl_net_dump_cb {
995 struct net *tgt_net;
996 struct net *ref_net;
997 struct sk_buff *skb;
998 struct net_fill_args fillargs;
999 int idx;
1000 int s_idx;
1001 };
1002
1003 /* Runs in RCU-critical section. */
rtnl_net_dumpid_one(int id,void * peer,void * data)1004 static int rtnl_net_dumpid_one(int id, void *peer, void *data)
1005 {
1006 struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
1007 int ret;
1008
1009 if (net_cb->idx < net_cb->s_idx)
1010 goto cont;
1011
1012 net_cb->fillargs.nsid = id;
1013 if (net_cb->fillargs.add_ref)
1014 net_cb->fillargs.ref_nsid = __peernet2id(net_cb->ref_net, peer);
1015 ret = rtnl_net_fill(net_cb->skb, &net_cb->fillargs);
1016 if (ret < 0)
1017 return ret;
1018
1019 cont:
1020 net_cb->idx++;
1021 return 0;
1022 }
1023
rtnl_valid_dump_net_req(const struct nlmsghdr * nlh,struct sock * sk,struct rtnl_net_dump_cb * net_cb,struct netlink_callback * cb)1024 static int rtnl_valid_dump_net_req(const struct nlmsghdr *nlh, struct sock *sk,
1025 struct rtnl_net_dump_cb *net_cb,
1026 struct netlink_callback *cb)
1027 {
1028 struct netlink_ext_ack *extack = cb->extack;
1029 struct nlattr *tb[NETNSA_MAX + 1];
1030 int err, i;
1031
1032 err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb,
1033 NETNSA_MAX, rtnl_net_policy,
1034 extack);
1035 if (err < 0)
1036 return err;
1037
1038 for (i = 0; i <= NETNSA_MAX; i++) {
1039 if (!tb[i])
1040 continue;
1041
1042 if (i == NETNSA_TARGET_NSID) {
1043 struct net *net;
1044
1045 net = rtnl_get_net_ns_capable(sk, nla_get_s32(tb[i]));
1046 if (IS_ERR(net)) {
1047 NL_SET_BAD_ATTR(extack, tb[i]);
1048 NL_SET_ERR_MSG(extack,
1049 "Invalid target network namespace id");
1050 return PTR_ERR(net);
1051 }
1052 net_cb->fillargs.add_ref = true;
1053 net_cb->ref_net = net_cb->tgt_net;
1054 net_cb->tgt_net = net;
1055 } else {
1056 NL_SET_BAD_ATTR(extack, tb[i]);
1057 NL_SET_ERR_MSG(extack,
1058 "Unsupported attribute in dump request");
1059 return -EINVAL;
1060 }
1061 }
1062
1063 return 0;
1064 }
1065
rtnl_net_dumpid(struct sk_buff * skb,struct netlink_callback * cb)1066 static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
1067 {
1068 struct rtnl_net_dump_cb net_cb = {
1069 .tgt_net = sock_net(skb->sk),
1070 .skb = skb,
1071 .fillargs = {
1072 .portid = NETLINK_CB(cb->skb).portid,
1073 .seq = cb->nlh->nlmsg_seq,
1074 .flags = NLM_F_MULTI,
1075 .cmd = RTM_NEWNSID,
1076 },
1077 .idx = 0,
1078 .s_idx = cb->args[0],
1079 };
1080 int err = 0;
1081
1082 if (cb->strict_check) {
1083 err = rtnl_valid_dump_net_req(cb->nlh, skb->sk, &net_cb, cb);
1084 if (err < 0)
1085 goto end;
1086 }
1087
1088 rcu_read_lock();
1089 idr_for_each(&net_cb.tgt_net->netns_ids, rtnl_net_dumpid_one, &net_cb);
1090 rcu_read_unlock();
1091
1092 cb->args[0] = net_cb.idx;
1093 end:
1094 if (net_cb.fillargs.add_ref)
1095 put_net(net_cb.tgt_net);
1096 return err;
1097 }
1098
rtnl_net_notifyid(struct net * net,int cmd,int id,u32 portid,struct nlmsghdr * nlh,gfp_t gfp)1099 static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
1100 struct nlmsghdr *nlh, gfp_t gfp)
1101 {
1102 struct net_fill_args fillargs = {
1103 .portid = portid,
1104 .seq = nlh ? nlh->nlmsg_seq : 0,
1105 .cmd = cmd,
1106 .nsid = id,
1107 };
1108 struct sk_buff *msg;
1109 int err = -ENOMEM;
1110
1111 msg = nlmsg_new(rtnl_net_get_size(), gfp);
1112 if (!msg)
1113 goto out;
1114
1115 err = rtnl_net_fill(msg, &fillargs);
1116 if (err < 0)
1117 goto err_out;
1118
1119 rtnl_notify(msg, net, portid, RTNLGRP_NSID, nlh, gfp);
1120 return;
1121
1122 err_out:
1123 nlmsg_free(msg);
1124 out:
1125 rtnl_set_sk_err(net, RTNLGRP_NSID, err);
1126 }
1127
1128 #ifdef CONFIG_NET_NS
netns_ipv4_struct_check(void)1129 static void __init netns_ipv4_struct_check(void)
1130 {
1131 /* TX readonly hotpath cache lines */
1132 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1133 sysctl_tcp_early_retrans);
1134 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1135 sysctl_tcp_tso_win_divisor);
1136 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1137 sysctl_tcp_tso_rtt_log);
1138 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1139 sysctl_tcp_autocorking);
1140 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1141 sysctl_tcp_min_snd_mss);
1142 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1143 sysctl_tcp_notsent_lowat);
1144 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1145 sysctl_tcp_limit_output_bytes);
1146 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1147 sysctl_tcp_min_rtt_wlen);
1148 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1149 sysctl_tcp_wmem);
1150 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1151 sysctl_ip_fwd_use_pmtu);
1152 CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_tx, 33);
1153
1154 /* TXRX readonly hotpath cache lines */
1155 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_txrx,
1156 sysctl_tcp_moderate_rcvbuf);
1157 CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_txrx, 1);
1158
1159 /* RX readonly hotpath cache line */
1160 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1161 sysctl_ip_early_demux);
1162 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1163 sysctl_tcp_early_demux);
1164 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1165 sysctl_tcp_reordering);
1166 CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1167 sysctl_tcp_rmem);
1168 CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_rx, 18);
1169 }
1170 #endif
1171
net_ns_init(void)1172 void __init net_ns_init(void)
1173 {
1174 struct net_generic *ng;
1175
1176 #ifdef CONFIG_NET_NS
1177 netns_ipv4_struct_check();
1178 net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
1179 SMP_CACHE_BYTES,
1180 SLAB_PANIC|SLAB_ACCOUNT, NULL);
1181
1182 /* Create workqueue for cleanup */
1183 netns_wq = create_singlethread_workqueue("netns");
1184 if (!netns_wq)
1185 panic("Could not create netns workq");
1186 #endif
1187
1188 ng = net_alloc_generic();
1189 if (!ng)
1190 panic("Could not allocate generic netns");
1191
1192 rcu_assign_pointer(init_net.gen, ng);
1193
1194 #ifdef CONFIG_KEYS
1195 init_net.key_domain = &init_net_key_domain;
1196 #endif
1197 down_write(&pernet_ops_rwsem);
1198 preinit_net(&init_net);
1199 if (setup_net(&init_net, &init_user_ns))
1200 panic("Could not setup the initial network namespace");
1201
1202 init_net_initialized = true;
1203 up_write(&pernet_ops_rwsem);
1204
1205 if (register_pernet_subsys(&net_ns_ops))
1206 panic("Could not register network namespace subsystems");
1207
1208 rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL,
1209 RTNL_FLAG_DOIT_UNLOCKED);
1210 rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid,
1211 RTNL_FLAG_DOIT_UNLOCKED |
1212 RTNL_FLAG_DUMP_UNLOCKED);
1213 }
1214
free_exit_list(struct pernet_operations * ops,struct list_head * net_exit_list)1215 static void free_exit_list(struct pernet_operations *ops, struct list_head *net_exit_list)
1216 {
1217 ops_pre_exit_list(ops, net_exit_list);
1218 synchronize_rcu();
1219
1220 if (ops->exit_batch_rtnl) {
1221 LIST_HEAD(dev_kill_list);
1222
1223 rtnl_lock();
1224 ops->exit_batch_rtnl(net_exit_list, &dev_kill_list);
1225 unregister_netdevice_many(&dev_kill_list);
1226 rtnl_unlock();
1227 }
1228 ops_exit_list(ops, net_exit_list);
1229
1230 ops_free_list(ops, net_exit_list);
1231 }
1232
1233 #ifdef CONFIG_NET_NS
__register_pernet_operations(struct list_head * list,struct pernet_operations * ops)1234 static int __register_pernet_operations(struct list_head *list,
1235 struct pernet_operations *ops)
1236 {
1237 struct net *net;
1238 int error;
1239 LIST_HEAD(net_exit_list);
1240
1241 list_add_tail(&ops->list, list);
1242 if (ops->init || (ops->id && ops->size)) {
1243 /* We held write locked pernet_ops_rwsem, and parallel
1244 * setup_net() and cleanup_net() are not possible.
1245 */
1246 for_each_net(net) {
1247 error = ops_init(ops, net);
1248 if (error)
1249 goto out_undo;
1250 list_add_tail(&net->exit_list, &net_exit_list);
1251 }
1252 }
1253 return 0;
1254
1255 out_undo:
1256 /* If I have an error cleanup all namespaces I initialized */
1257 list_del(&ops->list);
1258 free_exit_list(ops, &net_exit_list);
1259 return error;
1260 }
1261
__unregister_pernet_operations(struct pernet_operations * ops)1262 static void __unregister_pernet_operations(struct pernet_operations *ops)
1263 {
1264 struct net *net;
1265 LIST_HEAD(net_exit_list);
1266
1267 list_del(&ops->list);
1268 /* See comment in __register_pernet_operations() */
1269 for_each_net(net)
1270 list_add_tail(&net->exit_list, &net_exit_list);
1271
1272 free_exit_list(ops, &net_exit_list);
1273 }
1274
1275 #else
1276
__register_pernet_operations(struct list_head * list,struct pernet_operations * ops)1277 static int __register_pernet_operations(struct list_head *list,
1278 struct pernet_operations *ops)
1279 {
1280 if (!init_net_initialized) {
1281 list_add_tail(&ops->list, list);
1282 return 0;
1283 }
1284
1285 return ops_init(ops, &init_net);
1286 }
1287
__unregister_pernet_operations(struct pernet_operations * ops)1288 static void __unregister_pernet_operations(struct pernet_operations *ops)
1289 {
1290 if (!init_net_initialized) {
1291 list_del(&ops->list);
1292 } else {
1293 LIST_HEAD(net_exit_list);
1294 list_add(&init_net.exit_list, &net_exit_list);
1295 free_exit_list(ops, &net_exit_list);
1296 }
1297 }
1298
1299 #endif /* CONFIG_NET_NS */
1300
1301 static DEFINE_IDA(net_generic_ids);
1302
register_pernet_operations(struct list_head * list,struct pernet_operations * ops)1303 static int register_pernet_operations(struct list_head *list,
1304 struct pernet_operations *ops)
1305 {
1306 int error;
1307
1308 if (ops->id) {
1309 error = ida_alloc_min(&net_generic_ids, MIN_PERNET_OPS_ID,
1310 GFP_KERNEL);
1311 if (error < 0)
1312 return error;
1313 *ops->id = error;
1314 /* This does not require READ_ONCE as writers already hold
1315 * pernet_ops_rwsem. But WRITE_ONCE is needed to protect
1316 * net_alloc_generic.
1317 */
1318 WRITE_ONCE(max_gen_ptrs, max(max_gen_ptrs, *ops->id + 1));
1319 }
1320 error = __register_pernet_operations(list, ops);
1321 if (error) {
1322 rcu_barrier();
1323 if (ops->id)
1324 ida_free(&net_generic_ids, *ops->id);
1325 }
1326
1327 return error;
1328 }
1329
unregister_pernet_operations(struct pernet_operations * ops)1330 static void unregister_pernet_operations(struct pernet_operations *ops)
1331 {
1332 __unregister_pernet_operations(ops);
1333 rcu_barrier();
1334 if (ops->id)
1335 ida_free(&net_generic_ids, *ops->id);
1336 }
1337
1338 /**
1339 * register_pernet_subsys - register a network namespace subsystem
1340 * @ops: pernet operations structure for the subsystem
1341 *
1342 * Register a subsystem which has init and exit functions
1343 * that are called when network namespaces are created and
1344 * destroyed respectively.
1345 *
1346 * When registered all network namespace init functions are
1347 * called for every existing network namespace. Allowing kernel
1348 * modules to have a race free view of the set of network namespaces.
1349 *
1350 * When a new network namespace is created all of the init
1351 * methods are called in the order in which they were registered.
1352 *
1353 * When a network namespace is destroyed all of the exit methods
1354 * are called in the reverse of the order with which they were
1355 * registered.
1356 */
register_pernet_subsys(struct pernet_operations * ops)1357 int register_pernet_subsys(struct pernet_operations *ops)
1358 {
1359 int error;
1360 down_write(&pernet_ops_rwsem);
1361 error = register_pernet_operations(first_device, ops);
1362 up_write(&pernet_ops_rwsem);
1363 return error;
1364 }
1365 EXPORT_SYMBOL_GPL(register_pernet_subsys);
1366
1367 /**
1368 * unregister_pernet_subsys - unregister a network namespace subsystem
1369 * @ops: pernet operations structure to manipulate
1370 *
1371 * Remove the pernet operations structure from the list to be
1372 * used when network namespaces are created or destroyed. In
1373 * addition run the exit method for all existing network
1374 * namespaces.
1375 */
unregister_pernet_subsys(struct pernet_operations * ops)1376 void unregister_pernet_subsys(struct pernet_operations *ops)
1377 {
1378 down_write(&pernet_ops_rwsem);
1379 unregister_pernet_operations(ops);
1380 up_write(&pernet_ops_rwsem);
1381 }
1382 EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
1383
1384 /**
1385 * register_pernet_device - register a network namespace device
1386 * @ops: pernet operations structure for the subsystem
1387 *
1388 * Register a device which has init and exit functions
1389 * that are called when network namespaces are created and
1390 * destroyed respectively.
1391 *
1392 * When registered all network namespace init functions are
1393 * called for every existing network namespace. Allowing kernel
1394 * modules to have a race free view of the set of network namespaces.
1395 *
1396 * When a new network namespace is created all of the init
1397 * methods are called in the order in which they were registered.
1398 *
1399 * When a network namespace is destroyed all of the exit methods
1400 * are called in the reverse of the order with which they were
1401 * registered.
1402 */
register_pernet_device(struct pernet_operations * ops)1403 int register_pernet_device(struct pernet_operations *ops)
1404 {
1405 int error;
1406 down_write(&pernet_ops_rwsem);
1407 error = register_pernet_operations(&pernet_list, ops);
1408 if (!error && (first_device == &pernet_list))
1409 first_device = &ops->list;
1410 up_write(&pernet_ops_rwsem);
1411 return error;
1412 }
1413 EXPORT_SYMBOL_GPL(register_pernet_device);
1414
1415 /**
1416 * unregister_pernet_device - unregister a network namespace netdevice
1417 * @ops: pernet operations structure to manipulate
1418 *
1419 * Remove the pernet operations structure from the list to be
1420 * used when network namespaces are created or destroyed. In
1421 * addition run the exit method for all existing network
1422 * namespaces.
1423 */
unregister_pernet_device(struct pernet_operations * ops)1424 void unregister_pernet_device(struct pernet_operations *ops)
1425 {
1426 down_write(&pernet_ops_rwsem);
1427 if (&ops->list == first_device)
1428 first_device = first_device->next;
1429 unregister_pernet_operations(ops);
1430 up_write(&pernet_ops_rwsem);
1431 }
1432 EXPORT_SYMBOL_GPL(unregister_pernet_device);
1433
1434 #ifdef CONFIG_NET_NS
netns_get(struct task_struct * task)1435 static struct ns_common *netns_get(struct task_struct *task)
1436 {
1437 struct net *net = NULL;
1438 struct nsproxy *nsproxy;
1439
1440 task_lock(task);
1441 nsproxy = task->nsproxy;
1442 if (nsproxy)
1443 net = get_net(nsproxy->net_ns);
1444 task_unlock(task);
1445
1446 return net ? &net->ns : NULL;
1447 }
1448
to_net_ns(struct ns_common * ns)1449 static inline struct net *to_net_ns(struct ns_common *ns)
1450 {
1451 return container_of(ns, struct net, ns);
1452 }
1453
netns_put(struct ns_common * ns)1454 static void netns_put(struct ns_common *ns)
1455 {
1456 put_net(to_net_ns(ns));
1457 }
1458
netns_install(struct nsset * nsset,struct ns_common * ns)1459 static int netns_install(struct nsset *nsset, struct ns_common *ns)
1460 {
1461 struct nsproxy *nsproxy = nsset->nsproxy;
1462 struct net *net = to_net_ns(ns);
1463
1464 if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
1465 !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
1466 return -EPERM;
1467
1468 put_net(nsproxy->net_ns);
1469 nsproxy->net_ns = get_net(net);
1470 return 0;
1471 }
1472
netns_owner(struct ns_common * ns)1473 static struct user_namespace *netns_owner(struct ns_common *ns)
1474 {
1475 return to_net_ns(ns)->user_ns;
1476 }
1477
1478 const struct proc_ns_operations netns_operations = {
1479 .name = "net",
1480 .type = CLONE_NEWNET,
1481 .get = netns_get,
1482 .put = netns_put,
1483 .install = netns_install,
1484 .owner = netns_owner,
1485 };
1486 #endif
1487