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v6.13.7
   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
  34static LIST_HEAD(pernet_list);
  35static struct list_head *first_device = &pernet_list;
  36
  37LIST_HEAD(net_namespace_list);
  38EXPORT_SYMBOL_GPL(net_namespace_list);
  39
  40/* Protects net_namespace_list. Nests iside rtnl_lock() */
  41DECLARE_RWSEM(net_rwsem);
  42EXPORT_SYMBOL_GPL(net_rwsem);
  43
  44#ifdef CONFIG_KEYS
  45static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) };
  46#endif
  47
  48struct net init_net;
 
 
 
 
 
 
  49EXPORT_SYMBOL(init_net);
  50
  51static 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 */
  58DECLARE_RWSEM(pernet_ops_rwsem);
 
  59
  60#define MIN_PERNET_OPS_ID	\
  61	((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *))
  62
  63#define INITIAL_NET_GEN_PTRS	13 /* +1 for len +2 for rcu_head */
  64
  65static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
  66
  67DEFINE_COOKIE(net_cookie);
  68
  69static struct net_generic *net_alloc_generic(void)
  70{
  71	unsigned int gen_ptrs = READ_ONCE(max_gen_ptrs);
  72	unsigned int generic_size;
  73	struct net_generic *ng;
  74
  75	generic_size = offsetof(struct net_generic, ptr[gen_ptrs]);
  76
  77	ng = kzalloc(generic_size, GFP_KERNEL);
  78	if (ng)
  79		ng->s.len = gen_ptrs;
  80
  81	return ng;
  82}
  83
  84static int net_assign_generic(struct net *net, unsigned int id, void *data)
  85{
  86	struct net_generic *ng, *old_ng;
  87
  88	BUG_ON(id < MIN_PERNET_OPS_ID);
  89
  90	old_ng = rcu_dereference_protected(net->gen,
  91					   lockdep_is_held(&pernet_ops_rwsem));
  92	if (old_ng->s.len > id) {
  93		old_ng->ptr[id] = data;
  94		return 0;
  95	}
  96
  97	ng = net_alloc_generic();
  98	if (!ng)
  99		return -ENOMEM;
 100
 101	/*
 102	 * Some synchronisation notes:
 103	 *
 104	 * The net_generic explores the net->gen array inside rcu
 105	 * read section. Besides once set the net->gen->ptr[x]
 106	 * pointer never changes (see rules in netns/generic.h).
 107	 *
 108	 * That said, we simply duplicate this array and schedule
 109	 * the old copy for kfree after a grace period.
 110	 */
 111
 112	memcpy(&ng->ptr[MIN_PERNET_OPS_ID], &old_ng->ptr[MIN_PERNET_OPS_ID],
 113	       (old_ng->s.len - MIN_PERNET_OPS_ID) * sizeof(void *));
 114	ng->ptr[id] = data;
 115
 116	rcu_assign_pointer(net->gen, ng);
 117	kfree_rcu(old_ng, s.rcu);
 118	return 0;
 119}
 120
 121static int ops_init(const struct pernet_operations *ops, struct net *net)
 122{
 123	struct net_generic *ng;
 124	int err = -ENOMEM;
 125	void *data = NULL;
 126
 127	if (ops->id) {
 128		data = kzalloc(ops->size, GFP_KERNEL);
 129		if (!data)
 130			goto out;
 131
 132		err = net_assign_generic(net, *ops->id, data);
 133		if (err)
 134			goto cleanup;
 135	}
 136	err = 0;
 137	if (ops->init)
 138		err = ops->init(net);
 139	if (!err)
 140		return 0;
 141
 142	if (ops->id) {
 143		ng = rcu_dereference_protected(net->gen,
 144					       lockdep_is_held(&pernet_ops_rwsem));
 145		ng->ptr[*ops->id] = NULL;
 146	}
 147
 148cleanup:
 149	kfree(data);
 150
 151out:
 152	return err;
 153}
 154
 
 
 
 
 
 
 
 155static void ops_pre_exit_list(const struct pernet_operations *ops,
 156			      struct list_head *net_exit_list)
 157{
 158	struct net *net;
 159
 160	if (ops->pre_exit) {
 161		list_for_each_entry(net, net_exit_list, exit_list)
 162			ops->pre_exit(net);
 163	}
 164}
 165
 166static void ops_exit_list(const struct pernet_operations *ops,
 167			  struct list_head *net_exit_list)
 168{
 169	struct net *net;
 170	if (ops->exit) {
 171		list_for_each_entry(net, net_exit_list, exit_list) {
 172			ops->exit(net);
 173			cond_resched();
 174		}
 175	}
 176	if (ops->exit_batch)
 177		ops->exit_batch(net_exit_list);
 178}
 179
 180static void ops_free_list(const struct pernet_operations *ops,
 181			  struct list_head *net_exit_list)
 182{
 183	struct net *net;
 184
 185	if (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 */
 192static 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
 210static 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 */
 218static 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
 
 
 
 
 
 
 
 
 231static 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 */
 236int 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}
 271EXPORT_SYMBOL_GPL(peernet2id_alloc);
 272
 273/* This function returns, if assigned, the id of a peer netns. */
 274int 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}
 284EXPORT_SYMBOL(peernet2id);
 285
 286/* This function returns true is the peer netns has an id assigned into the
 287 * current netns.
 288 */
 289bool peernet_has_id(const struct net *net, struct net *peer)
 290{
 291	return peernet2id(net, peer) >= 0;
 292}
 293
 294struct 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}
 309EXPORT_SYMBOL_GPL(get_net_ns_by_id);
 310
 311static __net_init void preinit_net_sysctl(struct net *net)
 
 
 
 312{
 313	net->core.sysctl_somaxconn = SOMAXCONN;
 314	/* Limits per socket sk_omem_alloc usage.
 315	 * TCP zerocopy regular usage needs 128 KB.
 316	 */
 317	net->core.sysctl_optmem_max = 128 * 1024;
 318	net->core.sysctl_txrehash = SOCK_TXREHASH_ENABLED;
 319	net->core.sysctl_tstamp_allow_data = 1;
 320}
 321
 322/* init code that must occur even if setup_net() is not called. */
 323static __net_init void preinit_net(struct net *net, struct user_namespace *user_ns)
 324{
 325	refcount_set(&net->passive, 1);
 326	refcount_set(&net->ns.count, 1);
 327	ref_tracker_dir_init(&net->refcnt_tracker, 128, "net refcnt");
 328	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net notrefcnt");
 329
 330	get_random_bytes(&net->hash_mix, sizeof(u32));
 331	net->dev_base_seq = 1;
 332	net->user_ns = user_ns;
 333
 334	idr_init(&net->netns_ids);
 335	spin_lock_init(&net->nsid_lock);
 336	mutex_init(&net->ipv4.ra_mutex);
 337
 338#ifdef CONFIG_DEBUG_NET_SMALL_RTNL
 339	mutex_init(&net->rtnl_mutex);
 340	lock_set_cmp_fn(&net->rtnl_mutex, rtnl_net_lock_cmp_fn, NULL);
 341#endif
 342
 343	preinit_net_sysctl(net);
 344}
 345
 346/*
 347 * setup_net runs the initializers for the network namespace object.
 348 */
 349static __net_init int setup_net(struct net *net)
 350{
 351	/* Must be called with pernet_ops_rwsem held */
 352	const struct pernet_operations *ops, *saved_ops;
 353	LIST_HEAD(net_exit_list);
 354	LIST_HEAD(dev_kill_list);
 355	int error = 0;
 356
 357	preempt_disable();
 358	net->net_cookie = gen_cookie_next(&net_cookie);
 359	preempt_enable();
 360
 361	list_for_each_entry(ops, &pernet_list, list) {
 362		error = ops_init(ops, net);
 363		if (error < 0)
 364			goto out_undo;
 365	}
 366	down_write(&net_rwsem);
 367	list_add_tail_rcu(&net->list, &net_namespace_list);
 368	up_write(&net_rwsem);
 369out:
 370	return error;
 371
 372out_undo:
 373	/* Walk through the list backwards calling the exit functions
 374	 * for the pernet modules whose init functions did not fail.
 375	 */
 376	list_add(&net->exit_list, &net_exit_list);
 377	saved_ops = ops;
 378	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
 379		ops_pre_exit_list(ops, &net_exit_list);
 380
 381	synchronize_rcu();
 382
 383	ops = saved_ops;
 384	rtnl_lock();
 385	list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
 386		if (ops->exit_batch_rtnl)
 387			ops->exit_batch_rtnl(&net_exit_list, &dev_kill_list);
 388	}
 389	unregister_netdevice_many(&dev_kill_list);
 390	rtnl_unlock();
 391
 392	ops = saved_ops;
 393	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
 394		ops_exit_list(ops, &net_exit_list);
 395
 396	ops = saved_ops;
 397	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
 398		ops_free_list(ops, &net_exit_list);
 399
 400	rcu_barrier();
 401	goto out;
 402}
 403
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 404#ifdef CONFIG_NET_NS
 405static struct ucounts *inc_net_namespaces(struct user_namespace *ns)
 406{
 407	return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES);
 408}
 409
 410static void dec_net_namespaces(struct ucounts *ucounts)
 411{
 412	dec_ucount(ucounts, UCOUNT_NET_NAMESPACES);
 413}
 414
 415static struct kmem_cache *net_cachep __ro_after_init;
 416static struct workqueue_struct *netns_wq;
 417
 418static struct net *net_alloc(void)
 419{
 420	struct net *net = NULL;
 421	struct net_generic *ng;
 422
 423	ng = net_alloc_generic();
 424	if (!ng)
 425		goto out;
 426
 427	net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
 428	if (!net)
 429		goto out_free;
 430
 431#ifdef CONFIG_KEYS
 432	net->key_domain = kzalloc(sizeof(struct key_tag), GFP_KERNEL);
 433	if (!net->key_domain)
 434		goto out_free_2;
 435	refcount_set(&net->key_domain->usage, 1);
 436#endif
 437
 438	rcu_assign_pointer(net->gen, ng);
 439out:
 440	return net;
 441
 442#ifdef CONFIG_KEYS
 443out_free_2:
 444	kmem_cache_free(net_cachep, net);
 445	net = NULL;
 446#endif
 447out_free:
 448	kfree(ng);
 449	goto out;
 450}
 451
 452static LLIST_HEAD(defer_free_list);
 453
 454static void net_complete_free(void)
 455{
 456	struct llist_node *kill_list;
 457	struct net *net, *next;
 458
 459	/* Get the list of namespaces to free from last round. */
 460	kill_list = llist_del_all(&defer_free_list);
 461
 462	llist_for_each_entry_safe(net, next, kill_list, defer_free_list)
 463		kmem_cache_free(net_cachep, net);
 464
 465}
 466
 467void net_passive_dec(struct net *net)
 468{
 469	if (refcount_dec_and_test(&net->passive)) {
 470		kfree(rcu_access_pointer(net->gen));
 471
 472		/* There should not be any trackers left there. */
 473		ref_tracker_dir_exit(&net->notrefcnt_tracker);
 474
 475		/* Wait for an extra rcu_barrier() before final free. */
 476		llist_add(&net->defer_free_list, &defer_free_list);
 477	}
 478}
 479
 480void net_drop_ns(void *p)
 481{
 482	struct net *net = (struct net *)p;
 483
 484	if (net)
 485		net_passive_dec(net);
 486}
 487
 488struct net *copy_net_ns(unsigned long flags,
 489			struct user_namespace *user_ns, struct net *old_net)
 490{
 491	struct ucounts *ucounts;
 492	struct net *net;
 493	int rv;
 494
 495	if (!(flags & CLONE_NEWNET))
 496		return get_net(old_net);
 497
 498	ucounts = inc_net_namespaces(user_ns);
 499	if (!ucounts)
 500		return ERR_PTR(-ENOSPC);
 501
 502	net = net_alloc();
 503	if (!net) {
 504		rv = -ENOMEM;
 505		goto dec_ucounts;
 506	}
 507
 508	preinit_net(net, user_ns);
 509	net->ucounts = ucounts;
 510	get_user_ns(user_ns);
 511
 512	rv = down_read_killable(&pernet_ops_rwsem);
 513	if (rv < 0)
 514		goto put_userns;
 515
 516	rv = setup_net(net);
 517
 518	up_read(&pernet_ops_rwsem);
 519
 520	if (rv < 0) {
 521put_userns:
 522#ifdef CONFIG_KEYS
 523		key_remove_domain(net->key_domain);
 524#endif
 525		put_user_ns(user_ns);
 526		net_passive_dec(net);
 527dec_ucounts:
 528		dec_net_namespaces(ucounts);
 529		return ERR_PTR(rv);
 530	}
 531	return net;
 532}
 533
 534/**
 535 * net_ns_get_ownership - get sysfs ownership data for @net
 536 * @net: network namespace in question (can be NULL)
 537 * @uid: kernel user ID for sysfs objects
 538 * @gid: kernel group ID for sysfs objects
 539 *
 540 * Returns the uid/gid pair of root in the user namespace associated with the
 541 * given network namespace.
 542 */
 543void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid)
 544{
 545	if (net) {
 546		kuid_t ns_root_uid = make_kuid(net->user_ns, 0);
 547		kgid_t ns_root_gid = make_kgid(net->user_ns, 0);
 548
 549		if (uid_valid(ns_root_uid))
 550			*uid = ns_root_uid;
 551
 552		if (gid_valid(ns_root_gid))
 553			*gid = ns_root_gid;
 554	} else {
 555		*uid = GLOBAL_ROOT_UID;
 556		*gid = GLOBAL_ROOT_GID;
 557	}
 558}
 559EXPORT_SYMBOL_GPL(net_ns_get_ownership);
 560
 561static void unhash_nsid(struct net *net, struct net *last)
 562{
 563	struct net *tmp;
 564	/* This function is only called from cleanup_net() work,
 565	 * and this work is the only process, that may delete
 566	 * a net from net_namespace_list. So, when the below
 567	 * is executing, the list may only grow. Thus, we do not
 568	 * use for_each_net_rcu() or net_rwsem.
 569	 */
 570	for_each_net(tmp) {
 571		int id;
 572
 573		spin_lock_bh(&tmp->nsid_lock);
 574		id = __peernet2id(tmp, net);
 575		if (id >= 0)
 576			idr_remove(&tmp->netns_ids, id);
 577		spin_unlock_bh(&tmp->nsid_lock);
 578		if (id >= 0)
 579			rtnl_net_notifyid(tmp, RTM_DELNSID, id, 0, NULL,
 580					  GFP_KERNEL);
 581		if (tmp == last)
 582			break;
 583	}
 584	spin_lock_bh(&net->nsid_lock);
 585	idr_destroy(&net->netns_ids);
 586	spin_unlock_bh(&net->nsid_lock);
 587}
 588
 589static LLIST_HEAD(cleanup_list);
 590
 591static void cleanup_net(struct work_struct *work)
 592{
 593	const struct pernet_operations *ops;
 594	struct net *net, *tmp, *last;
 595	struct llist_node *net_kill_list;
 596	LIST_HEAD(net_exit_list);
 597	LIST_HEAD(dev_kill_list);
 598
 599	/* Atomically snapshot the list of namespaces to cleanup */
 600	net_kill_list = llist_del_all(&cleanup_list);
 601
 602	down_read(&pernet_ops_rwsem);
 603
 604	/* Don't let anyone else find us. */
 605	down_write(&net_rwsem);
 606	llist_for_each_entry(net, net_kill_list, cleanup_list)
 607		list_del_rcu(&net->list);
 608	/* Cache last net. After we unlock rtnl, no one new net
 609	 * added to net_namespace_list can assign nsid pointer
 610	 * to a net from net_kill_list (see peernet2id_alloc()).
 611	 * So, we skip them in unhash_nsid().
 612	 *
 613	 * Note, that unhash_nsid() does not delete nsid links
 614	 * between net_kill_list's nets, as they've already
 615	 * deleted from net_namespace_list. But, this would be
 616	 * useless anyway, as netns_ids are destroyed there.
 617	 */
 618	last = list_last_entry(&net_namespace_list, struct net, list);
 619	up_write(&net_rwsem);
 620
 621	llist_for_each_entry(net, net_kill_list, cleanup_list) {
 622		unhash_nsid(net, last);
 623		list_add_tail(&net->exit_list, &net_exit_list);
 624	}
 625
 626	/* Run all of the network namespace pre_exit methods */
 627	list_for_each_entry_reverse(ops, &pernet_list, list)
 628		ops_pre_exit_list(ops, &net_exit_list);
 629
 630	/*
 631	 * Another CPU might be rcu-iterating the list, wait for it.
 632	 * This needs to be before calling the exit() notifiers, so
 633	 * the rcu_barrier() below isn't sufficient alone.
 634	 * Also the pre_exit() and exit() methods need this barrier.
 635	 */
 636	synchronize_rcu_expedited();
 637
 638	rtnl_lock();
 639	list_for_each_entry_reverse(ops, &pernet_list, list) {
 640		if (ops->exit_batch_rtnl)
 641			ops->exit_batch_rtnl(&net_exit_list, &dev_kill_list);
 642	}
 643	unregister_netdevice_many(&dev_kill_list);
 644	rtnl_unlock();
 645
 646	/* Run all of the network namespace exit methods */
 647	list_for_each_entry_reverse(ops, &pernet_list, list)
 648		ops_exit_list(ops, &net_exit_list);
 649
 650	/* Free the net generic variables */
 651	list_for_each_entry_reverse(ops, &pernet_list, list)
 652		ops_free_list(ops, &net_exit_list);
 653
 654	up_read(&pernet_ops_rwsem);
 655
 656	/* Ensure there are no outstanding rcu callbacks using this
 657	 * network namespace.
 658	 */
 659	rcu_barrier();
 660
 661	net_complete_free();
 662
 663	/* Finally it is safe to free my network namespace structure */
 664	list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
 665		list_del_init(&net->exit_list);
 666		dec_net_namespaces(net->ucounts);
 667#ifdef CONFIG_KEYS
 668		key_remove_domain(net->key_domain);
 669#endif
 670		put_user_ns(net->user_ns);
 671		net_passive_dec(net);
 672	}
 673}
 674
 675/**
 676 * net_ns_barrier - wait until concurrent net_cleanup_work is done
 677 *
 678 * cleanup_net runs from work queue and will first remove namespaces
 679 * from the global list, then run net exit functions.
 680 *
 681 * Call this in module exit path to make sure that all netns
 682 * ->exit ops have been invoked before the function is removed.
 683 */
 684void net_ns_barrier(void)
 685{
 686	down_write(&pernet_ops_rwsem);
 687	up_write(&pernet_ops_rwsem);
 688}
 689EXPORT_SYMBOL(net_ns_barrier);
 690
 691static DECLARE_WORK(net_cleanup_work, cleanup_net);
 692
 693void __put_net(struct net *net)
 694{
 695	ref_tracker_dir_exit(&net->refcnt_tracker);
 696	/* Cleanup the network namespace in process context */
 697	if (llist_add(&net->cleanup_list, &cleanup_list))
 698		queue_work(netns_wq, &net_cleanup_work);
 699}
 700EXPORT_SYMBOL_GPL(__put_net);
 701
 702/**
 703 * get_net_ns - increment the refcount of the network namespace
 704 * @ns: common namespace (net)
 705 *
 706 * Returns the net's common namespace or ERR_PTR() if ref is zero.
 707 */
 708struct ns_common *get_net_ns(struct ns_common *ns)
 709{
 
 
 710	struct net *net;
 711
 712	net = maybe_get_net(container_of(ns, struct net, ns));
 713	if (net)
 714		return &net->ns;
 715	return ERR_PTR(-EINVAL);
 
 
 
 
 
 
 
 
 716}
 717EXPORT_SYMBOL_GPL(get_net_ns);
 718
 
 719struct net *get_net_ns_by_fd(int fd)
 720{
 721	CLASS(fd, f)(fd);
 722
 723	if (fd_empty(f))
 724		return ERR_PTR(-EBADF);
 725
 726	if (proc_ns_file(fd_file(f))) {
 727		struct ns_common *ns = get_proc_ns(file_inode(fd_file(f)));
 728		if (ns->ops == &netns_operations)
 729			return get_net(container_of(ns, struct net, ns));
 730	}
 731
 732	return ERR_PTR(-EINVAL);
 733}
 734EXPORT_SYMBOL_GPL(get_net_ns_by_fd);
 735#endif
 
 736
 737struct net *get_net_ns_by_pid(pid_t pid)
 738{
 739	struct task_struct *tsk;
 740	struct net *net;
 741
 742	/* Lookup the network namespace */
 743	net = ERR_PTR(-ESRCH);
 744	rcu_read_lock();
 745	tsk = find_task_by_vpid(pid);
 746	if (tsk) {
 747		struct nsproxy *nsproxy;
 748		task_lock(tsk);
 749		nsproxy = tsk->nsproxy;
 750		if (nsproxy)
 751			net = get_net(nsproxy->net_ns);
 752		task_unlock(tsk);
 753	}
 754	rcu_read_unlock();
 755	return net;
 756}
 757EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
 758
 759static __net_init int net_ns_net_init(struct net *net)
 760{
 761#ifdef CONFIG_NET_NS
 762	net->ns.ops = &netns_operations;
 763#endif
 764	return ns_alloc_inum(&net->ns);
 765}
 766
 767static __net_exit void net_ns_net_exit(struct net *net)
 768{
 769	ns_free_inum(&net->ns);
 770}
 771
 772static struct pernet_operations __net_initdata net_ns_ops = {
 773	.init = net_ns_net_init,
 774	.exit = net_ns_net_exit,
 775};
 776
 777static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = {
 778	[NETNSA_NONE]		= { .type = NLA_UNSPEC },
 779	[NETNSA_NSID]		= { .type = NLA_S32 },
 780	[NETNSA_PID]		= { .type = NLA_U32 },
 781	[NETNSA_FD]		= { .type = NLA_U32 },
 782	[NETNSA_TARGET_NSID]	= { .type = NLA_S32 },
 783};
 784
 785static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh,
 786			  struct netlink_ext_ack *extack)
 787{
 788	struct net *net = sock_net(skb->sk);
 789	struct nlattr *tb[NETNSA_MAX + 1];
 790	struct nlattr *nla;
 791	struct net *peer;
 792	int nsid, err;
 793
 794	err = nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg), tb,
 795				     NETNSA_MAX, rtnl_net_policy, extack);
 796	if (err < 0)
 797		return err;
 798	if (!tb[NETNSA_NSID]) {
 799		NL_SET_ERR_MSG(extack, "nsid is missing");
 800		return -EINVAL;
 801	}
 802	nsid = nla_get_s32(tb[NETNSA_NSID]);
 803
 804	if (tb[NETNSA_PID]) {
 805		peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
 806		nla = tb[NETNSA_PID];
 807	} else if (tb[NETNSA_FD]) {
 808		peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
 809		nla = tb[NETNSA_FD];
 810	} else {
 811		NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
 812		return -EINVAL;
 813	}
 814	if (IS_ERR(peer)) {
 815		NL_SET_BAD_ATTR(extack, nla);
 816		NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
 817		return PTR_ERR(peer);
 818	}
 819
 820	spin_lock_bh(&net->nsid_lock);
 821	if (__peernet2id(net, peer) >= 0) {
 822		spin_unlock_bh(&net->nsid_lock);
 823		err = -EEXIST;
 824		NL_SET_BAD_ATTR(extack, nla);
 825		NL_SET_ERR_MSG(extack,
 826			       "Peer netns already has a nsid assigned");
 827		goto out;
 828	}
 829
 830	err = alloc_netid(net, peer, nsid);
 831	spin_unlock_bh(&net->nsid_lock);
 832	if (err >= 0) {
 833		rtnl_net_notifyid(net, RTM_NEWNSID, err, NETLINK_CB(skb).portid,
 834				  nlh, GFP_KERNEL);
 835		err = 0;
 836	} else if (err == -ENOSPC && nsid >= 0) {
 837		err = -EEXIST;
 838		NL_SET_BAD_ATTR(extack, tb[NETNSA_NSID]);
 839		NL_SET_ERR_MSG(extack, "The specified nsid is already used");
 840	}
 841out:
 842	put_net(peer);
 843	return err;
 844}
 845
 846static int rtnl_net_get_size(void)
 847{
 848	return NLMSG_ALIGN(sizeof(struct rtgenmsg))
 849	       + nla_total_size(sizeof(s32)) /* NETNSA_NSID */
 850	       + nla_total_size(sizeof(s32)) /* NETNSA_CURRENT_NSID */
 851	       ;
 852}
 853
 854struct net_fill_args {
 855	u32 portid;
 856	u32 seq;
 857	int flags;
 858	int cmd;
 859	int nsid;
 860	bool add_ref;
 861	int ref_nsid;
 862};
 863
 864static int rtnl_net_fill(struct sk_buff *skb, struct net_fill_args *args)
 865{
 866	struct nlmsghdr *nlh;
 867	struct rtgenmsg *rth;
 868
 869	nlh = nlmsg_put(skb, args->portid, args->seq, args->cmd, sizeof(*rth),
 870			args->flags);
 871	if (!nlh)
 872		return -EMSGSIZE;
 873
 874	rth = nlmsg_data(nlh);
 875	rth->rtgen_family = AF_UNSPEC;
 876
 877	if (nla_put_s32(skb, NETNSA_NSID, args->nsid))
 878		goto nla_put_failure;
 879
 880	if (args->add_ref &&
 881	    nla_put_s32(skb, NETNSA_CURRENT_NSID, args->ref_nsid))
 882		goto nla_put_failure;
 883
 884	nlmsg_end(skb, nlh);
 885	return 0;
 886
 887nla_put_failure:
 888	nlmsg_cancel(skb, nlh);
 889	return -EMSGSIZE;
 890}
 891
 892static int rtnl_net_valid_getid_req(struct sk_buff *skb,
 893				    const struct nlmsghdr *nlh,
 894				    struct nlattr **tb,
 895				    struct netlink_ext_ack *extack)
 896{
 897	int i, err;
 898
 899	if (!netlink_strict_get_check(skb))
 900		return nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg),
 901					      tb, NETNSA_MAX, rtnl_net_policy,
 902					      extack);
 903
 904	err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb,
 905					    NETNSA_MAX, rtnl_net_policy,
 906					    extack);
 907	if (err)
 908		return err;
 909
 910	for (i = 0; i <= NETNSA_MAX; i++) {
 911		if (!tb[i])
 912			continue;
 913
 914		switch (i) {
 915		case NETNSA_PID:
 916		case NETNSA_FD:
 917		case NETNSA_NSID:
 918		case NETNSA_TARGET_NSID:
 919			break;
 920		default:
 921			NL_SET_ERR_MSG(extack, "Unsupported attribute in peer netns getid request");
 922			return -EINVAL;
 923		}
 924	}
 925
 926	return 0;
 927}
 928
 929static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh,
 930			  struct netlink_ext_ack *extack)
 931{
 932	struct net *net = sock_net(skb->sk);
 933	struct nlattr *tb[NETNSA_MAX + 1];
 934	struct net_fill_args fillargs = {
 935		.portid = NETLINK_CB(skb).portid,
 936		.seq = nlh->nlmsg_seq,
 937		.cmd = RTM_NEWNSID,
 938	};
 939	struct net *peer, *target = net;
 940	struct nlattr *nla;
 941	struct sk_buff *msg;
 942	int err;
 943
 944	err = rtnl_net_valid_getid_req(skb, nlh, tb, extack);
 945	if (err < 0)
 946		return err;
 947	if (tb[NETNSA_PID]) {
 948		peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
 949		nla = tb[NETNSA_PID];
 950	} else if (tb[NETNSA_FD]) {
 951		peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
 952		nla = tb[NETNSA_FD];
 953	} else if (tb[NETNSA_NSID]) {
 954		peer = get_net_ns_by_id(net, nla_get_s32(tb[NETNSA_NSID]));
 955		if (!peer)
 956			peer = ERR_PTR(-ENOENT);
 957		nla = tb[NETNSA_NSID];
 958	} else {
 959		NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
 960		return -EINVAL;
 961	}
 962
 963	if (IS_ERR(peer)) {
 964		NL_SET_BAD_ATTR(extack, nla);
 965		NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
 966		return PTR_ERR(peer);
 967	}
 968
 969	if (tb[NETNSA_TARGET_NSID]) {
 970		int id = nla_get_s32(tb[NETNSA_TARGET_NSID]);
 971
 972		target = rtnl_get_net_ns_capable(NETLINK_CB(skb).sk, id);
 973		if (IS_ERR(target)) {
 974			NL_SET_BAD_ATTR(extack, tb[NETNSA_TARGET_NSID]);
 975			NL_SET_ERR_MSG(extack,
 976				       "Target netns reference is invalid");
 977			err = PTR_ERR(target);
 978			goto out;
 979		}
 980		fillargs.add_ref = true;
 981		fillargs.ref_nsid = peernet2id(net, peer);
 982	}
 983
 984	msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
 985	if (!msg) {
 986		err = -ENOMEM;
 987		goto out;
 988	}
 989
 990	fillargs.nsid = peernet2id(target, peer);
 991	err = rtnl_net_fill(msg, &fillargs);
 992	if (err < 0)
 993		goto err_out;
 994
 995	err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid);
 996	goto out;
 997
 998err_out:
 999	nlmsg_free(msg);
1000out:
1001	if (fillargs.add_ref)
1002		put_net(target);
1003	put_net(peer);
1004	return err;
1005}
1006
1007struct rtnl_net_dump_cb {
1008	struct net *tgt_net;
1009	struct net *ref_net;
1010	struct sk_buff *skb;
1011	struct net_fill_args fillargs;
1012	int idx;
1013	int s_idx;
1014};
1015
1016/* Runs in RCU-critical section. */
1017static int rtnl_net_dumpid_one(int id, void *peer, void *data)
1018{
1019	struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
1020	int ret;
1021
1022	if (net_cb->idx < net_cb->s_idx)
1023		goto cont;
1024
1025	net_cb->fillargs.nsid = id;
1026	if (net_cb->fillargs.add_ref)
1027		net_cb->fillargs.ref_nsid = __peernet2id(net_cb->ref_net, peer);
1028	ret = rtnl_net_fill(net_cb->skb, &net_cb->fillargs);
1029	if (ret < 0)
1030		return ret;
1031
1032cont:
1033	net_cb->idx++;
1034	return 0;
1035}
1036
1037static int rtnl_valid_dump_net_req(const struct nlmsghdr *nlh, struct sock *sk,
1038				   struct rtnl_net_dump_cb *net_cb,
1039				   struct netlink_callback *cb)
1040{
1041	struct netlink_ext_ack *extack = cb->extack;
1042	struct nlattr *tb[NETNSA_MAX + 1];
1043	int err, i;
1044
1045	err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb,
1046					    NETNSA_MAX, rtnl_net_policy,
1047					    extack);
1048	if (err < 0)
1049		return err;
1050
1051	for (i = 0; i <= NETNSA_MAX; i++) {
1052		if (!tb[i])
1053			continue;
1054
1055		if (i == NETNSA_TARGET_NSID) {
1056			struct net *net;
1057
1058			net = rtnl_get_net_ns_capable(sk, nla_get_s32(tb[i]));
1059			if (IS_ERR(net)) {
1060				NL_SET_BAD_ATTR(extack, tb[i]);
1061				NL_SET_ERR_MSG(extack,
1062					       "Invalid target network namespace id");
1063				return PTR_ERR(net);
1064			}
1065			net_cb->fillargs.add_ref = true;
1066			net_cb->ref_net = net_cb->tgt_net;
1067			net_cb->tgt_net = net;
1068		} else {
1069			NL_SET_BAD_ATTR(extack, tb[i]);
1070			NL_SET_ERR_MSG(extack,
1071				       "Unsupported attribute in dump request");
1072			return -EINVAL;
1073		}
1074	}
1075
1076	return 0;
1077}
1078
1079static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
1080{
1081	struct rtnl_net_dump_cb net_cb = {
1082		.tgt_net = sock_net(skb->sk),
1083		.skb = skb,
1084		.fillargs = {
1085			.portid = NETLINK_CB(cb->skb).portid,
1086			.seq = cb->nlh->nlmsg_seq,
1087			.flags = NLM_F_MULTI,
1088			.cmd = RTM_NEWNSID,
1089		},
1090		.idx = 0,
1091		.s_idx = cb->args[0],
1092	};
1093	int err = 0;
1094
1095	if (cb->strict_check) {
1096		err = rtnl_valid_dump_net_req(cb->nlh, skb->sk, &net_cb, cb);
1097		if (err < 0)
1098			goto end;
1099	}
1100
1101	rcu_read_lock();
 
 
 
 
 
 
 
1102	idr_for_each(&net_cb.tgt_net->netns_ids, rtnl_net_dumpid_one, &net_cb);
1103	rcu_read_unlock();
 
 
 
1104
1105	cb->args[0] = net_cb.idx;
1106end:
1107	if (net_cb.fillargs.add_ref)
1108		put_net(net_cb.tgt_net);
1109	return err;
1110}
1111
1112static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
1113			      struct nlmsghdr *nlh, gfp_t gfp)
1114{
1115	struct net_fill_args fillargs = {
1116		.portid = portid,
1117		.seq = nlh ? nlh->nlmsg_seq : 0,
1118		.cmd = cmd,
1119		.nsid = id,
1120	};
1121	struct sk_buff *msg;
1122	int err = -ENOMEM;
1123
1124	msg = nlmsg_new(rtnl_net_get_size(), gfp);
1125	if (!msg)
1126		goto out;
1127
1128	err = rtnl_net_fill(msg, &fillargs);
1129	if (err < 0)
1130		goto err_out;
1131
1132	rtnl_notify(msg, net, portid, RTNLGRP_NSID, nlh, gfp);
1133	return;
1134
1135err_out:
1136	nlmsg_free(msg);
1137out:
1138	rtnl_set_sk_err(net, RTNLGRP_NSID, err);
1139}
1140
1141#ifdef CONFIG_NET_NS
1142static void __init netns_ipv4_struct_check(void)
1143{
1144	/* TX readonly hotpath cache lines */
1145	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1146				      sysctl_tcp_early_retrans);
1147	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1148				      sysctl_tcp_tso_win_divisor);
1149	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1150				      sysctl_tcp_tso_rtt_log);
1151	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1152				      sysctl_tcp_autocorking);
1153	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1154				      sysctl_tcp_min_snd_mss);
1155	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1156				      sysctl_tcp_notsent_lowat);
1157	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1158				      sysctl_tcp_limit_output_bytes);
1159	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1160				      sysctl_tcp_min_rtt_wlen);
1161	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1162				      sysctl_tcp_wmem);
1163	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_tx,
1164				      sysctl_ip_fwd_use_pmtu);
1165	CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_tx, 33);
1166
1167	/* TXRX readonly hotpath cache lines */
1168	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_txrx,
1169				      sysctl_tcp_moderate_rcvbuf);
1170	CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_txrx, 1);
1171
1172	/* RX readonly hotpath cache line */
1173	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1174				      sysctl_ip_early_demux);
1175	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1176				      sysctl_tcp_early_demux);
1177	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1178				      sysctl_tcp_l3mdev_accept);
1179	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1180				      sysctl_tcp_reordering);
1181	CACHELINE_ASSERT_GROUP_MEMBER(struct netns_ipv4, netns_ipv4_read_rx,
1182				      sysctl_tcp_rmem);
1183	CACHELINE_ASSERT_GROUP_SIZE(struct netns_ipv4, netns_ipv4_read_rx, 22);
1184}
1185#endif
1186
1187static const struct rtnl_msg_handler net_ns_rtnl_msg_handlers[] __initconst = {
1188	{.msgtype = RTM_NEWNSID, .doit = rtnl_net_newid,
1189	 .flags = RTNL_FLAG_DOIT_UNLOCKED},
1190	{.msgtype = RTM_GETNSID, .doit = rtnl_net_getid,
1191	 .dumpit = rtnl_net_dumpid,
1192	 .flags = RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},
1193};
1194
1195void __init net_ns_init(void)
1196{
1197	struct net_generic *ng;
1198
1199#ifdef CONFIG_NET_NS
1200	netns_ipv4_struct_check();
1201	net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
1202					SMP_CACHE_BYTES,
1203					SLAB_PANIC|SLAB_ACCOUNT, NULL);
1204
1205	/* Create workqueue for cleanup */
1206	netns_wq = create_singlethread_workqueue("netns");
1207	if (!netns_wq)
1208		panic("Could not create netns workq");
1209#endif
1210
1211	ng = net_alloc_generic();
1212	if (!ng)
1213		panic("Could not allocate generic netns");
1214
1215	rcu_assign_pointer(init_net.gen, ng);
1216
1217#ifdef CONFIG_KEYS
1218	init_net.key_domain = &init_net_key_domain;
1219#endif
1220	preinit_net(&init_net, &init_user_ns);
1221
1222	down_write(&pernet_ops_rwsem);
1223	if (setup_net(&init_net))
1224		panic("Could not setup the initial network namespace");
1225
1226	init_net_initialized = true;
1227	up_write(&pernet_ops_rwsem);
1228
1229	if (register_pernet_subsys(&net_ns_ops))
1230		panic("Could not register network namespace subsystems");
1231
1232	rtnl_register_many(net_ns_rtnl_msg_handlers);
1233}
1234
1235static void free_exit_list(struct pernet_operations *ops, struct list_head *net_exit_list)
1236{
1237	ops_pre_exit_list(ops, net_exit_list);
1238	synchronize_rcu();
1239
1240	if (ops->exit_batch_rtnl) {
1241		LIST_HEAD(dev_kill_list);
1242
1243		rtnl_lock();
1244		ops->exit_batch_rtnl(net_exit_list, &dev_kill_list);
1245		unregister_netdevice_many(&dev_kill_list);
1246		rtnl_unlock();
1247	}
1248	ops_exit_list(ops, net_exit_list);
1249
1250	ops_free_list(ops, net_exit_list);
1251}
1252
 
 
1253#ifdef CONFIG_NET_NS
1254static int __register_pernet_operations(struct list_head *list,
1255					struct pernet_operations *ops)
1256{
1257	struct net *net;
1258	int error;
1259	LIST_HEAD(net_exit_list);
1260
1261	list_add_tail(&ops->list, list);
1262	if (ops->init || ops->id) {
1263		/* We held write locked pernet_ops_rwsem, and parallel
1264		 * setup_net() and cleanup_net() are not possible.
1265		 */
1266		for_each_net(net) {
1267			error = ops_init(ops, net);
1268			if (error)
1269				goto out_undo;
1270			list_add_tail(&net->exit_list, &net_exit_list);
1271		}
1272	}
1273	return 0;
1274
1275out_undo:
1276	/* If I have an error cleanup all namespaces I initialized */
1277	list_del(&ops->list);
1278	free_exit_list(ops, &net_exit_list);
 
 
 
1279	return error;
1280}
1281
1282static void __unregister_pernet_operations(struct pernet_operations *ops)
1283{
1284	struct net *net;
1285	LIST_HEAD(net_exit_list);
1286
1287	list_del(&ops->list);
1288	/* See comment in __register_pernet_operations() */
1289	for_each_net(net)
1290		list_add_tail(&net->exit_list, &net_exit_list);
1291
1292	free_exit_list(ops, &net_exit_list);
 
 
1293}
1294
1295#else
1296
1297static int __register_pernet_operations(struct list_head *list,
1298					struct pernet_operations *ops)
1299{
1300	if (!init_net_initialized) {
1301		list_add_tail(&ops->list, list);
1302		return 0;
1303	}
1304
1305	return ops_init(ops, &init_net);
1306}
1307
1308static void __unregister_pernet_operations(struct pernet_operations *ops)
1309{
1310	if (!init_net_initialized) {
1311		list_del(&ops->list);
1312	} else {
1313		LIST_HEAD(net_exit_list);
1314		list_add(&init_net.exit_list, &net_exit_list);
1315		free_exit_list(ops, &net_exit_list);
 
 
 
1316	}
1317}
1318
1319#endif /* CONFIG_NET_NS */
1320
1321static DEFINE_IDA(net_generic_ids);
1322
1323static int register_pernet_operations(struct list_head *list,
1324				      struct pernet_operations *ops)
1325{
1326	int error;
1327
1328	if (WARN_ON(!!ops->id ^ !!ops->size))
1329		return -EINVAL;
1330
1331	if (ops->id) {
1332		error = ida_alloc_min(&net_generic_ids, MIN_PERNET_OPS_ID,
1333				GFP_KERNEL);
1334		if (error < 0)
1335			return error;
1336		*ops->id = error;
1337		/* This does not require READ_ONCE as writers already hold
1338		 * pernet_ops_rwsem. But WRITE_ONCE is needed to protect
1339		 * net_alloc_generic.
1340		 */
1341		WRITE_ONCE(max_gen_ptrs, max(max_gen_ptrs, *ops->id + 1));
1342	}
1343	error = __register_pernet_operations(list, ops);
1344	if (error) {
1345		rcu_barrier();
1346		if (ops->id)
1347			ida_free(&net_generic_ids, *ops->id);
1348	}
1349
1350	return error;
1351}
1352
1353static void unregister_pernet_operations(struct pernet_operations *ops)
1354{
1355	__unregister_pernet_operations(ops);
1356	rcu_barrier();
1357	if (ops->id)
1358		ida_free(&net_generic_ids, *ops->id);
1359}
1360
1361/**
1362 *      register_pernet_subsys - register a network namespace subsystem
1363 *	@ops:  pernet operations structure for the subsystem
1364 *
1365 *	Register a subsystem which has init and exit functions
1366 *	that are called when network namespaces are created and
1367 *	destroyed respectively.
1368 *
1369 *	When registered all network namespace init functions are
1370 *	called for every existing network namespace.  Allowing kernel
1371 *	modules to have a race free view of the set of network namespaces.
1372 *
1373 *	When a new network namespace is created all of the init
1374 *	methods are called in the order in which they were registered.
1375 *
1376 *	When a network namespace is destroyed all of the exit methods
1377 *	are called in the reverse of the order with which they were
1378 *	registered.
1379 */
1380int register_pernet_subsys(struct pernet_operations *ops)
1381{
1382	int error;
1383	down_write(&pernet_ops_rwsem);
1384	error =  register_pernet_operations(first_device, ops);
1385	up_write(&pernet_ops_rwsem);
1386	return error;
1387}
1388EXPORT_SYMBOL_GPL(register_pernet_subsys);
1389
1390/**
1391 *      unregister_pernet_subsys - unregister a network namespace subsystem
1392 *	@ops: pernet operations structure to manipulate
1393 *
1394 *	Remove the pernet operations structure from the list to be
1395 *	used when network namespaces are created or destroyed.  In
1396 *	addition run the exit method for all existing network
1397 *	namespaces.
1398 */
1399void unregister_pernet_subsys(struct pernet_operations *ops)
1400{
1401	down_write(&pernet_ops_rwsem);
1402	unregister_pernet_operations(ops);
1403	up_write(&pernet_ops_rwsem);
1404}
1405EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
1406
1407/**
1408 *      register_pernet_device - register a network namespace device
1409 *	@ops:  pernet operations structure for the subsystem
1410 *
1411 *	Register a device which has init and exit functions
1412 *	that are called when network namespaces are created and
1413 *	destroyed respectively.
1414 *
1415 *	When registered all network namespace init functions are
1416 *	called for every existing network namespace.  Allowing kernel
1417 *	modules to have a race free view of the set of network namespaces.
1418 *
1419 *	When a new network namespace is created all of the init
1420 *	methods are called in the order in which they were registered.
1421 *
1422 *	When a network namespace is destroyed all of the exit methods
1423 *	are called in the reverse of the order with which they were
1424 *	registered.
1425 */
1426int register_pernet_device(struct pernet_operations *ops)
1427{
1428	int error;
1429	down_write(&pernet_ops_rwsem);
1430	error = register_pernet_operations(&pernet_list, ops);
1431	if (!error && (first_device == &pernet_list))
1432		first_device = &ops->list;
1433	up_write(&pernet_ops_rwsem);
1434	return error;
1435}
1436EXPORT_SYMBOL_GPL(register_pernet_device);
1437
1438/**
1439 *      unregister_pernet_device - unregister a network namespace netdevice
1440 *	@ops: pernet operations structure to manipulate
1441 *
1442 *	Remove the pernet operations structure from the list to be
1443 *	used when network namespaces are created or destroyed.  In
1444 *	addition run the exit method for all existing network
1445 *	namespaces.
1446 */
1447void unregister_pernet_device(struct pernet_operations *ops)
1448{
1449	down_write(&pernet_ops_rwsem);
1450	if (&ops->list == first_device)
1451		first_device = first_device->next;
1452	unregister_pernet_operations(ops);
1453	up_write(&pernet_ops_rwsem);
1454}
1455EXPORT_SYMBOL_GPL(unregister_pernet_device);
1456
1457#ifdef CONFIG_NET_NS
1458static struct ns_common *netns_get(struct task_struct *task)
1459{
1460	struct net *net = NULL;
1461	struct nsproxy *nsproxy;
1462
1463	task_lock(task);
1464	nsproxy = task->nsproxy;
1465	if (nsproxy)
1466		net = get_net(nsproxy->net_ns);
1467	task_unlock(task);
1468
1469	return net ? &net->ns : NULL;
1470}
1471
1472static inline struct net *to_net_ns(struct ns_common *ns)
1473{
1474	return container_of(ns, struct net, ns);
1475}
1476
1477static void netns_put(struct ns_common *ns)
1478{
1479	put_net(to_net_ns(ns));
1480}
1481
1482static int netns_install(struct nsset *nsset, struct ns_common *ns)
1483{
1484	struct nsproxy *nsproxy = nsset->nsproxy;
1485	struct net *net = to_net_ns(ns);
1486
1487	if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
1488	    !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
1489		return -EPERM;
1490
1491	put_net(nsproxy->net_ns);
1492	nsproxy->net_ns = get_net(net);
1493	return 0;
1494}
1495
1496static struct user_namespace *netns_owner(struct ns_common *ns)
1497{
1498	return to_net_ns(ns)->user_ns;
1499}
1500
1501const struct proc_ns_operations netns_operations = {
1502	.name		= "net",
1503	.type		= CLONE_NEWNET,
1504	.get		= netns_get,
1505	.put		= netns_put,
1506	.install	= netns_install,
1507	.owner		= netns_owner,
1508};
1509#endif
v5.4
   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
  23#include <net/sock.h>
  24#include <net/netlink.h>
  25#include <net/net_namespace.h>
  26#include <net/netns/generic.h>
  27
  28/*
  29 *	Our network namespace constructor/destructor lists
  30 */
  31
  32static LIST_HEAD(pernet_list);
  33static struct list_head *first_device = &pernet_list;
  34
  35LIST_HEAD(net_namespace_list);
  36EXPORT_SYMBOL_GPL(net_namespace_list);
  37
  38/* Protects net_namespace_list. Nests iside rtnl_lock() */
  39DECLARE_RWSEM(net_rwsem);
  40EXPORT_SYMBOL_GPL(net_rwsem);
  41
  42#ifdef CONFIG_KEYS
  43static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) };
  44#endif
  45
  46struct net init_net = {
  47	.count		= REFCOUNT_INIT(1),
  48	.dev_base_head	= LIST_HEAD_INIT(init_net.dev_base_head),
  49#ifdef CONFIG_KEYS
  50	.key_domain	= &init_net_key_domain,
  51#endif
  52};
  53EXPORT_SYMBOL(init_net);
  54
  55static bool init_net_initialized;
  56/*
  57 * pernet_ops_rwsem: protects: pernet_list, net_generic_ids,
  58 * init_net_initialized and first_device pointer.
  59 * This is internal net namespace object. Please, don't use it
  60 * outside.
  61 */
  62DECLARE_RWSEM(pernet_ops_rwsem);
  63EXPORT_SYMBOL_GPL(pernet_ops_rwsem);
  64
  65#define MIN_PERNET_OPS_ID	\
  66	((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *))
  67
  68#define INITIAL_NET_GEN_PTRS	13 /* +1 for len +2 for rcu_head */
  69
  70static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS;
  71
 
 
  72static struct net_generic *net_alloc_generic(void)
  73{
 
 
  74	struct net_generic *ng;
  75	unsigned int generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]);
 
  76
  77	ng = kzalloc(generic_size, GFP_KERNEL);
  78	if (ng)
  79		ng->s.len = max_gen_ptrs;
  80
  81	return ng;
  82}
  83
  84static int net_assign_generic(struct net *net, unsigned int id, void *data)
  85{
  86	struct net_generic *ng, *old_ng;
  87
  88	BUG_ON(id < MIN_PERNET_OPS_ID);
  89
  90	old_ng = rcu_dereference_protected(net->gen,
  91					   lockdep_is_held(&pernet_ops_rwsem));
  92	if (old_ng->s.len > id) {
  93		old_ng->ptr[id] = data;
  94		return 0;
  95	}
  96
  97	ng = net_alloc_generic();
  98	if (ng == NULL)
  99		return -ENOMEM;
 100
 101	/*
 102	 * Some synchronisation notes:
 103	 *
 104	 * The net_generic explores the net->gen array inside rcu
 105	 * read section. Besides once set the net->gen->ptr[x]
 106	 * pointer never changes (see rules in netns/generic.h).
 107	 *
 108	 * That said, we simply duplicate this array and schedule
 109	 * the old copy for kfree after a grace period.
 110	 */
 111
 112	memcpy(&ng->ptr[MIN_PERNET_OPS_ID], &old_ng->ptr[MIN_PERNET_OPS_ID],
 113	       (old_ng->s.len - MIN_PERNET_OPS_ID) * sizeof(void *));
 114	ng->ptr[id] = data;
 115
 116	rcu_assign_pointer(net->gen, ng);
 117	kfree_rcu(old_ng, s.rcu);
 118	return 0;
 119}
 120
 121static int ops_init(const struct pernet_operations *ops, struct net *net)
 122{
 
 123	int err = -ENOMEM;
 124	void *data = NULL;
 125
 126	if (ops->id && ops->size) {
 127		data = kzalloc(ops->size, GFP_KERNEL);
 128		if (!data)
 129			goto out;
 130
 131		err = net_assign_generic(net, *ops->id, data);
 132		if (err)
 133			goto cleanup;
 134	}
 135	err = 0;
 136	if (ops->init)
 137		err = ops->init(net);
 138	if (!err)
 139		return 0;
 140
 
 
 
 
 
 
 141cleanup:
 142	kfree(data);
 143
 144out:
 145	return err;
 146}
 147
 148static void ops_free(const struct pernet_operations *ops, struct net *net)
 149{
 150	if (ops->id && ops->size) {
 151		kfree(net_generic(net, *ops->id));
 152	}
 153}
 154
 155static void ops_pre_exit_list(const struct pernet_operations *ops,
 156			      struct list_head *net_exit_list)
 157{
 158	struct net *net;
 159
 160	if (ops->pre_exit) {
 161		list_for_each_entry(net, net_exit_list, exit_list)
 162			ops->pre_exit(net);
 163	}
 164}
 165
 166static void ops_exit_list(const struct pernet_operations *ops,
 167			  struct list_head *net_exit_list)
 168{
 169	struct net *net;
 170	if (ops->exit) {
 171		list_for_each_entry(net, net_exit_list, exit_list)
 172			ops->exit(net);
 
 
 173	}
 174	if (ops->exit_batch)
 175		ops->exit_batch(net_exit_list);
 176}
 177
 178static void ops_free_list(const struct pernet_operations *ops,
 179			  struct list_head *net_exit_list)
 180{
 181	struct net *net;
 182	if (ops->size && ops->id) {
 
 183		list_for_each_entry(net, net_exit_list, exit_list)
 184			ops_free(ops, net);
 185	}
 186}
 187
 188/* should be called with nsid_lock held */
 189static int alloc_netid(struct net *net, struct net *peer, int reqid)
 190{
 191	int min = 0, max = 0;
 192
 193	if (reqid >= 0) {
 194		min = reqid;
 195		max = reqid + 1;
 196	}
 197
 198	return idr_alloc(&net->netns_ids, peer, min, max, GFP_ATOMIC);
 199}
 200
 201/* This function is used by idr_for_each(). If net is equal to peer, the
 202 * function returns the id so that idr_for_each() stops. Because we cannot
 203 * returns the id 0 (idr_for_each() will not stop), we return the magic value
 204 * NET_ID_ZERO (-1) for it.
 205 */
 206#define NET_ID_ZERO -1
 207static int net_eq_idr(int id, void *net, void *peer)
 208{
 209	if (net_eq(net, peer))
 210		return id ? : NET_ID_ZERO;
 211	return 0;
 212}
 213
 214/* Should be called with nsid_lock held. If a new id is assigned, the bool alloc
 215 * is set to true, thus the caller knows that the new id must be notified via
 216 * rtnl.
 217 */
 218static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc)
 219{
 220	int id = idr_for_each(&net->netns_ids, net_eq_idr, peer);
 221	bool alloc_it = *alloc;
 222
 223	*alloc = false;
 224
 225	/* Magic value for id 0. */
 226	if (id == NET_ID_ZERO)
 227		return 0;
 228	if (id > 0)
 229		return id;
 230
 231	if (alloc_it) {
 232		id = alloc_netid(net, peer, -1);
 233		*alloc = true;
 234		return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED;
 235	}
 236
 237	return NETNSA_NSID_NOT_ASSIGNED;
 238}
 239
 240/* should be called with nsid_lock held */
 241static int __peernet2id(struct net *net, struct net *peer)
 242{
 243	bool no = false;
 244
 245	return __peernet2id_alloc(net, peer, &no);
 246}
 247
 248static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
 249			      struct nlmsghdr *nlh, gfp_t gfp);
 250/* This function returns the id of a peer netns. If no id is assigned, one will
 251 * be allocated and returned.
 252 */
 253int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp)
 254{
 255	bool alloc = false, alive = false;
 256	int id;
 257
 258	if (refcount_read(&net->count) == 0)
 259		return NETNSA_NSID_NOT_ASSIGNED;
 
 260	spin_lock_bh(&net->nsid_lock);
 261	/*
 262	 * When peer is obtained from RCU lists, we may race with
 
 
 
 
 
 263	 * its cleanup. Check whether it's alive, and this guarantees
 264	 * we never hash a peer back to net->netns_ids, after it has
 265	 * just been idr_remove()'d from there in cleanup_net().
 266	 */
 267	if (maybe_get_net(peer))
 268		alive = alloc = true;
 269	id = __peernet2id_alloc(net, peer, &alloc);
 
 
 
 270	spin_unlock_bh(&net->nsid_lock);
 271	if (alloc && id >= 0)
 272		rtnl_net_notifyid(net, RTM_NEWNSID, id, 0, NULL, gfp);
 273	if (alive)
 274		put_net(peer);
 
 
 
 275	return id;
 276}
 277EXPORT_SYMBOL_GPL(peernet2id_alloc);
 278
 279/* This function returns, if assigned, the id of a peer netns. */
 280int peernet2id(struct net *net, struct net *peer)
 281{
 282	int id;
 283
 284	spin_lock_bh(&net->nsid_lock);
 285	id = __peernet2id(net, peer);
 286	spin_unlock_bh(&net->nsid_lock);
 
 287	return id;
 288}
 289EXPORT_SYMBOL(peernet2id);
 290
 291/* This function returns true is the peer netns has an id assigned into the
 292 * current netns.
 293 */
 294bool peernet_has_id(struct net *net, struct net *peer)
 295{
 296	return peernet2id(net, peer) >= 0;
 297}
 298
 299struct net *get_net_ns_by_id(struct net *net, int id)
 300{
 301	struct net *peer;
 302
 303	if (id < 0)
 304		return NULL;
 305
 306	rcu_read_lock();
 307	peer = idr_find(&net->netns_ids, id);
 308	if (peer)
 309		peer = maybe_get_net(peer);
 310	rcu_read_unlock();
 311
 312	return peer;
 313}
 
 314
 315/*
 316 * setup_net runs the initializers for the network namespace object.
 317 */
 318static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
 319{
 320	/* Must be called with pernet_ops_rwsem held */
 321	const struct pernet_operations *ops, *saved_ops;
 322	int error = 0;
 323	LIST_HEAD(net_exit_list);
 
 
 
 
 324
 325	refcount_set(&net->count, 1);
 
 
 326	refcount_set(&net->passive, 1);
 
 
 
 
 327	get_random_bytes(&net->hash_mix, sizeof(u32));
 328	net->dev_base_seq = 1;
 329	net->user_ns = user_ns;
 
 330	idr_init(&net->netns_ids);
 331	spin_lock_init(&net->nsid_lock);
 332	mutex_init(&net->ipv4.ra_mutex);
 333
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 334	list_for_each_entry(ops, &pernet_list, list) {
 335		error = ops_init(ops, net);
 336		if (error < 0)
 337			goto out_undo;
 338	}
 339	down_write(&net_rwsem);
 340	list_add_tail_rcu(&net->list, &net_namespace_list);
 341	up_write(&net_rwsem);
 342out:
 343	return error;
 344
 345out_undo:
 346	/* Walk through the list backwards calling the exit functions
 347	 * for the pernet modules whose init functions did not fail.
 348	 */
 349	list_add(&net->exit_list, &net_exit_list);
 350	saved_ops = ops;
 351	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
 352		ops_pre_exit_list(ops, &net_exit_list);
 353
 354	synchronize_rcu();
 355
 356	ops = saved_ops;
 
 
 
 
 
 
 
 
 
 357	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
 358		ops_exit_list(ops, &net_exit_list);
 359
 360	ops = saved_ops;
 361	list_for_each_entry_continue_reverse(ops, &pernet_list, list)
 362		ops_free_list(ops, &net_exit_list);
 363
 364	rcu_barrier();
 365	goto out;
 366}
 367
 368static int __net_init net_defaults_init_net(struct net *net)
 369{
 370	net->core.sysctl_somaxconn = SOMAXCONN;
 371	return 0;
 372}
 373
 374static struct pernet_operations net_defaults_ops = {
 375	.init = net_defaults_init_net,
 376};
 377
 378static __init int net_defaults_init(void)
 379{
 380	if (register_pernet_subsys(&net_defaults_ops))
 381		panic("Cannot initialize net default settings");
 382
 383	return 0;
 384}
 385
 386core_initcall(net_defaults_init);
 387
 388#ifdef CONFIG_NET_NS
 389static struct ucounts *inc_net_namespaces(struct user_namespace *ns)
 390{
 391	return inc_ucount(ns, current_euid(), UCOUNT_NET_NAMESPACES);
 392}
 393
 394static void dec_net_namespaces(struct ucounts *ucounts)
 395{
 396	dec_ucount(ucounts, UCOUNT_NET_NAMESPACES);
 397}
 398
 399static struct kmem_cache *net_cachep __ro_after_init;
 400static struct workqueue_struct *netns_wq;
 401
 402static struct net *net_alloc(void)
 403{
 404	struct net *net = NULL;
 405	struct net_generic *ng;
 406
 407	ng = net_alloc_generic();
 408	if (!ng)
 409		goto out;
 410
 411	net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
 412	if (!net)
 413		goto out_free;
 414
 415#ifdef CONFIG_KEYS
 416	net->key_domain = kzalloc(sizeof(struct key_tag), GFP_KERNEL);
 417	if (!net->key_domain)
 418		goto out_free_2;
 419	refcount_set(&net->key_domain->usage, 1);
 420#endif
 421
 422	rcu_assign_pointer(net->gen, ng);
 423out:
 424	return net;
 425
 426#ifdef CONFIG_KEYS
 427out_free_2:
 428	kmem_cache_free(net_cachep, net);
 429	net = NULL;
 430#endif
 431out_free:
 432	kfree(ng);
 433	goto out;
 434}
 435
 436static void net_free(struct net *net)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 437{
 438	kfree(rcu_access_pointer(net->gen));
 439	kmem_cache_free(net_cachep, net);
 
 
 
 
 
 
 
 440}
 441
 442void net_drop_ns(void *p)
 443{
 444	struct net *ns = p;
 445	if (ns && refcount_dec_and_test(&ns->passive))
 446		net_free(ns);
 
 447}
 448
 449struct net *copy_net_ns(unsigned long flags,
 450			struct user_namespace *user_ns, struct net *old_net)
 451{
 452	struct ucounts *ucounts;
 453	struct net *net;
 454	int rv;
 455
 456	if (!(flags & CLONE_NEWNET))
 457		return get_net(old_net);
 458
 459	ucounts = inc_net_namespaces(user_ns);
 460	if (!ucounts)
 461		return ERR_PTR(-ENOSPC);
 462
 463	net = net_alloc();
 464	if (!net) {
 465		rv = -ENOMEM;
 466		goto dec_ucounts;
 467	}
 468	refcount_set(&net->passive, 1);
 
 469	net->ucounts = ucounts;
 470	get_user_ns(user_ns);
 471
 472	rv = down_read_killable(&pernet_ops_rwsem);
 473	if (rv < 0)
 474		goto put_userns;
 475
 476	rv = setup_net(net, user_ns);
 477
 478	up_read(&pernet_ops_rwsem);
 479
 480	if (rv < 0) {
 481put_userns:
 
 482		key_remove_domain(net->key_domain);
 
 483		put_user_ns(user_ns);
 484		net_drop_ns(net);
 485dec_ucounts:
 486		dec_net_namespaces(ucounts);
 487		return ERR_PTR(rv);
 488	}
 489	return net;
 490}
 491
 492/**
 493 * net_ns_get_ownership - get sysfs ownership data for @net
 494 * @net: network namespace in question (can be NULL)
 495 * @uid: kernel user ID for sysfs objects
 496 * @gid: kernel group ID for sysfs objects
 497 *
 498 * Returns the uid/gid pair of root in the user namespace associated with the
 499 * given network namespace.
 500 */
 501void net_ns_get_ownership(const struct net *net, kuid_t *uid, kgid_t *gid)
 502{
 503	if (net) {
 504		kuid_t ns_root_uid = make_kuid(net->user_ns, 0);
 505		kgid_t ns_root_gid = make_kgid(net->user_ns, 0);
 506
 507		if (uid_valid(ns_root_uid))
 508			*uid = ns_root_uid;
 509
 510		if (gid_valid(ns_root_gid))
 511			*gid = ns_root_gid;
 512	} else {
 513		*uid = GLOBAL_ROOT_UID;
 514		*gid = GLOBAL_ROOT_GID;
 515	}
 516}
 517EXPORT_SYMBOL_GPL(net_ns_get_ownership);
 518
 519static void unhash_nsid(struct net *net, struct net *last)
 520{
 521	struct net *tmp;
 522	/* This function is only called from cleanup_net() work,
 523	 * and this work is the only process, that may delete
 524	 * a net from net_namespace_list. So, when the below
 525	 * is executing, the list may only grow. Thus, we do not
 526	 * use for_each_net_rcu() or net_rwsem.
 527	 */
 528	for_each_net(tmp) {
 529		int id;
 530
 531		spin_lock_bh(&tmp->nsid_lock);
 532		id = __peernet2id(tmp, net);
 533		if (id >= 0)
 534			idr_remove(&tmp->netns_ids, id);
 535		spin_unlock_bh(&tmp->nsid_lock);
 536		if (id >= 0)
 537			rtnl_net_notifyid(tmp, RTM_DELNSID, id, 0, NULL,
 538					  GFP_KERNEL);
 539		if (tmp == last)
 540			break;
 541	}
 542	spin_lock_bh(&net->nsid_lock);
 543	idr_destroy(&net->netns_ids);
 544	spin_unlock_bh(&net->nsid_lock);
 545}
 546
 547static LLIST_HEAD(cleanup_list);
 548
 549static void cleanup_net(struct work_struct *work)
 550{
 551	const struct pernet_operations *ops;
 552	struct net *net, *tmp, *last;
 553	struct llist_node *net_kill_list;
 554	LIST_HEAD(net_exit_list);
 
 555
 556	/* Atomically snapshot the list of namespaces to cleanup */
 557	net_kill_list = llist_del_all(&cleanup_list);
 558
 559	down_read(&pernet_ops_rwsem);
 560
 561	/* Don't let anyone else find us. */
 562	down_write(&net_rwsem);
 563	llist_for_each_entry(net, net_kill_list, cleanup_list)
 564		list_del_rcu(&net->list);
 565	/* Cache last net. After we unlock rtnl, no one new net
 566	 * added to net_namespace_list can assign nsid pointer
 567	 * to a net from net_kill_list (see peernet2id_alloc()).
 568	 * So, we skip them in unhash_nsid().
 569	 *
 570	 * Note, that unhash_nsid() does not delete nsid links
 571	 * between net_kill_list's nets, as they've already
 572	 * deleted from net_namespace_list. But, this would be
 573	 * useless anyway, as netns_ids are destroyed there.
 574	 */
 575	last = list_last_entry(&net_namespace_list, struct net, list);
 576	up_write(&net_rwsem);
 577
 578	llist_for_each_entry(net, net_kill_list, cleanup_list) {
 579		unhash_nsid(net, last);
 580		list_add_tail(&net->exit_list, &net_exit_list);
 581	}
 582
 583	/* Run all of the network namespace pre_exit methods */
 584	list_for_each_entry_reverse(ops, &pernet_list, list)
 585		ops_pre_exit_list(ops, &net_exit_list);
 586
 587	/*
 588	 * Another CPU might be rcu-iterating the list, wait for it.
 589	 * This needs to be before calling the exit() notifiers, so
 590	 * the rcu_barrier() below isn't sufficient alone.
 591	 * Also the pre_exit() and exit() methods need this barrier.
 592	 */
 593	synchronize_rcu();
 
 
 
 
 
 
 
 
 594
 595	/* Run all of the network namespace exit methods */
 596	list_for_each_entry_reverse(ops, &pernet_list, list)
 597		ops_exit_list(ops, &net_exit_list);
 598
 599	/* Free the net generic variables */
 600	list_for_each_entry_reverse(ops, &pernet_list, list)
 601		ops_free_list(ops, &net_exit_list);
 602
 603	up_read(&pernet_ops_rwsem);
 604
 605	/* Ensure there are no outstanding rcu callbacks using this
 606	 * network namespace.
 607	 */
 608	rcu_barrier();
 609
 
 
 610	/* Finally it is safe to free my network namespace structure */
 611	list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
 612		list_del_init(&net->exit_list);
 613		dec_net_namespaces(net->ucounts);
 
 614		key_remove_domain(net->key_domain);
 
 615		put_user_ns(net->user_ns);
 616		net_drop_ns(net);
 617	}
 618}
 619
 620/**
 621 * net_ns_barrier - wait until concurrent net_cleanup_work is done
 622 *
 623 * cleanup_net runs from work queue and will first remove namespaces
 624 * from the global list, then run net exit functions.
 625 *
 626 * Call this in module exit path to make sure that all netns
 627 * ->exit ops have been invoked before the function is removed.
 628 */
 629void net_ns_barrier(void)
 630{
 631	down_write(&pernet_ops_rwsem);
 632	up_write(&pernet_ops_rwsem);
 633}
 634EXPORT_SYMBOL(net_ns_barrier);
 635
 636static DECLARE_WORK(net_cleanup_work, cleanup_net);
 637
 638void __put_net(struct net *net)
 639{
 
 640	/* Cleanup the network namespace in process context */
 641	if (llist_add(&net->cleanup_list, &cleanup_list))
 642		queue_work(netns_wq, &net_cleanup_work);
 643}
 644EXPORT_SYMBOL_GPL(__put_net);
 645
 646struct net *get_net_ns_by_fd(int fd)
 
 
 
 
 
 
 647{
 648	struct file *file;
 649	struct ns_common *ns;
 650	struct net *net;
 651
 652	file = proc_ns_fget(fd);
 653	if (IS_ERR(file))
 654		return ERR_CAST(file);
 655
 656	ns = get_proc_ns(file_inode(file));
 657	if (ns->ops == &netns_operations)
 658		net = get_net(container_of(ns, struct net, ns));
 659	else
 660		net = ERR_PTR(-EINVAL);
 661
 662	fput(file);
 663	return net;
 664}
 
 665
 666#else
 667struct net *get_net_ns_by_fd(int fd)
 668{
 
 
 
 
 
 
 
 
 
 
 
 669	return ERR_PTR(-EINVAL);
 670}
 
 671#endif
 672EXPORT_SYMBOL_GPL(get_net_ns_by_fd);
 673
 674struct net *get_net_ns_by_pid(pid_t pid)
 675{
 676	struct task_struct *tsk;
 677	struct net *net;
 678
 679	/* Lookup the network namespace */
 680	net = ERR_PTR(-ESRCH);
 681	rcu_read_lock();
 682	tsk = find_task_by_vpid(pid);
 683	if (tsk) {
 684		struct nsproxy *nsproxy;
 685		task_lock(tsk);
 686		nsproxy = tsk->nsproxy;
 687		if (nsproxy)
 688			net = get_net(nsproxy->net_ns);
 689		task_unlock(tsk);
 690	}
 691	rcu_read_unlock();
 692	return net;
 693}
 694EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
 695
 696static __net_init int net_ns_net_init(struct net *net)
 697{
 698#ifdef CONFIG_NET_NS
 699	net->ns.ops = &netns_operations;
 700#endif
 701	return ns_alloc_inum(&net->ns);
 702}
 703
 704static __net_exit void net_ns_net_exit(struct net *net)
 705{
 706	ns_free_inum(&net->ns);
 707}
 708
 709static struct pernet_operations __net_initdata net_ns_ops = {
 710	.init = net_ns_net_init,
 711	.exit = net_ns_net_exit,
 712};
 713
 714static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = {
 715	[NETNSA_NONE]		= { .type = NLA_UNSPEC },
 716	[NETNSA_NSID]		= { .type = NLA_S32 },
 717	[NETNSA_PID]		= { .type = NLA_U32 },
 718	[NETNSA_FD]		= { .type = NLA_U32 },
 719	[NETNSA_TARGET_NSID]	= { .type = NLA_S32 },
 720};
 721
 722static int rtnl_net_newid(struct sk_buff *skb, struct nlmsghdr *nlh,
 723			  struct netlink_ext_ack *extack)
 724{
 725	struct net *net = sock_net(skb->sk);
 726	struct nlattr *tb[NETNSA_MAX + 1];
 727	struct nlattr *nla;
 728	struct net *peer;
 729	int nsid, err;
 730
 731	err = nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg), tb,
 732				     NETNSA_MAX, rtnl_net_policy, extack);
 733	if (err < 0)
 734		return err;
 735	if (!tb[NETNSA_NSID]) {
 736		NL_SET_ERR_MSG(extack, "nsid is missing");
 737		return -EINVAL;
 738	}
 739	nsid = nla_get_s32(tb[NETNSA_NSID]);
 740
 741	if (tb[NETNSA_PID]) {
 742		peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
 743		nla = tb[NETNSA_PID];
 744	} else if (tb[NETNSA_FD]) {
 745		peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
 746		nla = tb[NETNSA_FD];
 747	} else {
 748		NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
 749		return -EINVAL;
 750	}
 751	if (IS_ERR(peer)) {
 752		NL_SET_BAD_ATTR(extack, nla);
 753		NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
 754		return PTR_ERR(peer);
 755	}
 756
 757	spin_lock_bh(&net->nsid_lock);
 758	if (__peernet2id(net, peer) >= 0) {
 759		spin_unlock_bh(&net->nsid_lock);
 760		err = -EEXIST;
 761		NL_SET_BAD_ATTR(extack, nla);
 762		NL_SET_ERR_MSG(extack,
 763			       "Peer netns already has a nsid assigned");
 764		goto out;
 765	}
 766
 767	err = alloc_netid(net, peer, nsid);
 768	spin_unlock_bh(&net->nsid_lock);
 769	if (err >= 0) {
 770		rtnl_net_notifyid(net, RTM_NEWNSID, err, NETLINK_CB(skb).portid,
 771				  nlh, GFP_KERNEL);
 772		err = 0;
 773	} else if (err == -ENOSPC && nsid >= 0) {
 774		err = -EEXIST;
 775		NL_SET_BAD_ATTR(extack, tb[NETNSA_NSID]);
 776		NL_SET_ERR_MSG(extack, "The specified nsid is already used");
 777	}
 778out:
 779	put_net(peer);
 780	return err;
 781}
 782
 783static int rtnl_net_get_size(void)
 784{
 785	return NLMSG_ALIGN(sizeof(struct rtgenmsg))
 786	       + nla_total_size(sizeof(s32)) /* NETNSA_NSID */
 787	       + nla_total_size(sizeof(s32)) /* NETNSA_CURRENT_NSID */
 788	       ;
 789}
 790
 791struct net_fill_args {
 792	u32 portid;
 793	u32 seq;
 794	int flags;
 795	int cmd;
 796	int nsid;
 797	bool add_ref;
 798	int ref_nsid;
 799};
 800
 801static int rtnl_net_fill(struct sk_buff *skb, struct net_fill_args *args)
 802{
 803	struct nlmsghdr *nlh;
 804	struct rtgenmsg *rth;
 805
 806	nlh = nlmsg_put(skb, args->portid, args->seq, args->cmd, sizeof(*rth),
 807			args->flags);
 808	if (!nlh)
 809		return -EMSGSIZE;
 810
 811	rth = nlmsg_data(nlh);
 812	rth->rtgen_family = AF_UNSPEC;
 813
 814	if (nla_put_s32(skb, NETNSA_NSID, args->nsid))
 815		goto nla_put_failure;
 816
 817	if (args->add_ref &&
 818	    nla_put_s32(skb, NETNSA_CURRENT_NSID, args->ref_nsid))
 819		goto nla_put_failure;
 820
 821	nlmsg_end(skb, nlh);
 822	return 0;
 823
 824nla_put_failure:
 825	nlmsg_cancel(skb, nlh);
 826	return -EMSGSIZE;
 827}
 828
 829static int rtnl_net_valid_getid_req(struct sk_buff *skb,
 830				    const struct nlmsghdr *nlh,
 831				    struct nlattr **tb,
 832				    struct netlink_ext_ack *extack)
 833{
 834	int i, err;
 835
 836	if (!netlink_strict_get_check(skb))
 837		return nlmsg_parse_deprecated(nlh, sizeof(struct rtgenmsg),
 838					      tb, NETNSA_MAX, rtnl_net_policy,
 839					      extack);
 840
 841	err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb,
 842					    NETNSA_MAX, rtnl_net_policy,
 843					    extack);
 844	if (err)
 845		return err;
 846
 847	for (i = 0; i <= NETNSA_MAX; i++) {
 848		if (!tb[i])
 849			continue;
 850
 851		switch (i) {
 852		case NETNSA_PID:
 853		case NETNSA_FD:
 854		case NETNSA_NSID:
 855		case NETNSA_TARGET_NSID:
 856			break;
 857		default:
 858			NL_SET_ERR_MSG(extack, "Unsupported attribute in peer netns getid request");
 859			return -EINVAL;
 860		}
 861	}
 862
 863	return 0;
 864}
 865
 866static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh,
 867			  struct netlink_ext_ack *extack)
 868{
 869	struct net *net = sock_net(skb->sk);
 870	struct nlattr *tb[NETNSA_MAX + 1];
 871	struct net_fill_args fillargs = {
 872		.portid = NETLINK_CB(skb).portid,
 873		.seq = nlh->nlmsg_seq,
 874		.cmd = RTM_NEWNSID,
 875	};
 876	struct net *peer, *target = net;
 877	struct nlattr *nla;
 878	struct sk_buff *msg;
 879	int err;
 880
 881	err = rtnl_net_valid_getid_req(skb, nlh, tb, extack);
 882	if (err < 0)
 883		return err;
 884	if (tb[NETNSA_PID]) {
 885		peer = get_net_ns_by_pid(nla_get_u32(tb[NETNSA_PID]));
 886		nla = tb[NETNSA_PID];
 887	} else if (tb[NETNSA_FD]) {
 888		peer = get_net_ns_by_fd(nla_get_u32(tb[NETNSA_FD]));
 889		nla = tb[NETNSA_FD];
 890	} else if (tb[NETNSA_NSID]) {
 891		peer = get_net_ns_by_id(net, nla_get_s32(tb[NETNSA_NSID]));
 892		if (!peer)
 893			peer = ERR_PTR(-ENOENT);
 894		nla = tb[NETNSA_NSID];
 895	} else {
 896		NL_SET_ERR_MSG(extack, "Peer netns reference is missing");
 897		return -EINVAL;
 898	}
 899
 900	if (IS_ERR(peer)) {
 901		NL_SET_BAD_ATTR(extack, nla);
 902		NL_SET_ERR_MSG(extack, "Peer netns reference is invalid");
 903		return PTR_ERR(peer);
 904	}
 905
 906	if (tb[NETNSA_TARGET_NSID]) {
 907		int id = nla_get_s32(tb[NETNSA_TARGET_NSID]);
 908
 909		target = rtnl_get_net_ns_capable(NETLINK_CB(skb).sk, id);
 910		if (IS_ERR(target)) {
 911			NL_SET_BAD_ATTR(extack, tb[NETNSA_TARGET_NSID]);
 912			NL_SET_ERR_MSG(extack,
 913				       "Target netns reference is invalid");
 914			err = PTR_ERR(target);
 915			goto out;
 916		}
 917		fillargs.add_ref = true;
 918		fillargs.ref_nsid = peernet2id(net, peer);
 919	}
 920
 921	msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
 922	if (!msg) {
 923		err = -ENOMEM;
 924		goto out;
 925	}
 926
 927	fillargs.nsid = peernet2id(target, peer);
 928	err = rtnl_net_fill(msg, &fillargs);
 929	if (err < 0)
 930		goto err_out;
 931
 932	err = rtnl_unicast(msg, net, NETLINK_CB(skb).portid);
 933	goto out;
 934
 935err_out:
 936	nlmsg_free(msg);
 937out:
 938	if (fillargs.add_ref)
 939		put_net(target);
 940	put_net(peer);
 941	return err;
 942}
 943
 944struct rtnl_net_dump_cb {
 945	struct net *tgt_net;
 946	struct net *ref_net;
 947	struct sk_buff *skb;
 948	struct net_fill_args fillargs;
 949	int idx;
 950	int s_idx;
 951};
 952
 
 953static int rtnl_net_dumpid_one(int id, void *peer, void *data)
 954{
 955	struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
 956	int ret;
 957
 958	if (net_cb->idx < net_cb->s_idx)
 959		goto cont;
 960
 961	net_cb->fillargs.nsid = id;
 962	if (net_cb->fillargs.add_ref)
 963		net_cb->fillargs.ref_nsid = __peernet2id(net_cb->ref_net, peer);
 964	ret = rtnl_net_fill(net_cb->skb, &net_cb->fillargs);
 965	if (ret < 0)
 966		return ret;
 967
 968cont:
 969	net_cb->idx++;
 970	return 0;
 971}
 972
 973static int rtnl_valid_dump_net_req(const struct nlmsghdr *nlh, struct sock *sk,
 974				   struct rtnl_net_dump_cb *net_cb,
 975				   struct netlink_callback *cb)
 976{
 977	struct netlink_ext_ack *extack = cb->extack;
 978	struct nlattr *tb[NETNSA_MAX + 1];
 979	int err, i;
 980
 981	err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct rtgenmsg), tb,
 982					    NETNSA_MAX, rtnl_net_policy,
 983					    extack);
 984	if (err < 0)
 985		return err;
 986
 987	for (i = 0; i <= NETNSA_MAX; i++) {
 988		if (!tb[i])
 989			continue;
 990
 991		if (i == NETNSA_TARGET_NSID) {
 992			struct net *net;
 993
 994			net = rtnl_get_net_ns_capable(sk, nla_get_s32(tb[i]));
 995			if (IS_ERR(net)) {
 996				NL_SET_BAD_ATTR(extack, tb[i]);
 997				NL_SET_ERR_MSG(extack,
 998					       "Invalid target network namespace id");
 999				return PTR_ERR(net);
1000			}
1001			net_cb->fillargs.add_ref = true;
1002			net_cb->ref_net = net_cb->tgt_net;
1003			net_cb->tgt_net = net;
1004		} else {
1005			NL_SET_BAD_ATTR(extack, tb[i]);
1006			NL_SET_ERR_MSG(extack,
1007				       "Unsupported attribute in dump request");
1008			return -EINVAL;
1009		}
1010	}
1011
1012	return 0;
1013}
1014
1015static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
1016{
1017	struct rtnl_net_dump_cb net_cb = {
1018		.tgt_net = sock_net(skb->sk),
1019		.skb = skb,
1020		.fillargs = {
1021			.portid = NETLINK_CB(cb->skb).portid,
1022			.seq = cb->nlh->nlmsg_seq,
1023			.flags = NLM_F_MULTI,
1024			.cmd = RTM_NEWNSID,
1025		},
1026		.idx = 0,
1027		.s_idx = cb->args[0],
1028	};
1029	int err = 0;
1030
1031	if (cb->strict_check) {
1032		err = rtnl_valid_dump_net_req(cb->nlh, skb->sk, &net_cb, cb);
1033		if (err < 0)
1034			goto end;
1035	}
1036
1037	spin_lock_bh(&net_cb.tgt_net->nsid_lock);
1038	if (net_cb.fillargs.add_ref &&
1039	    !net_eq(net_cb.ref_net, net_cb.tgt_net) &&
1040	    !spin_trylock_bh(&net_cb.ref_net->nsid_lock)) {
1041		spin_unlock_bh(&net_cb.tgt_net->nsid_lock);
1042		err = -EAGAIN;
1043		goto end;
1044	}
1045	idr_for_each(&net_cb.tgt_net->netns_ids, rtnl_net_dumpid_one, &net_cb);
1046	if (net_cb.fillargs.add_ref &&
1047	    !net_eq(net_cb.ref_net, net_cb.tgt_net))
1048		spin_unlock_bh(&net_cb.ref_net->nsid_lock);
1049	spin_unlock_bh(&net_cb.tgt_net->nsid_lock);
1050
1051	cb->args[0] = net_cb.idx;
1052end:
1053	if (net_cb.fillargs.add_ref)
1054		put_net(net_cb.tgt_net);
1055	return err < 0 ? err : skb->len;
1056}
1057
1058static void rtnl_net_notifyid(struct net *net, int cmd, int id, u32 portid,
1059			      struct nlmsghdr *nlh, gfp_t gfp)
1060{
1061	struct net_fill_args fillargs = {
1062		.portid = portid,
1063		.seq = nlh ? nlh->nlmsg_seq : 0,
1064		.cmd = cmd,
1065		.nsid = id,
1066	};
1067	struct sk_buff *msg;
1068	int err = -ENOMEM;
1069
1070	msg = nlmsg_new(rtnl_net_get_size(), gfp);
1071	if (!msg)
1072		goto out;
1073
1074	err = rtnl_net_fill(msg, &fillargs);
1075	if (err < 0)
1076		goto err_out;
1077
1078	rtnl_notify(msg, net, portid, RTNLGRP_NSID, nlh, gfp);
1079	return;
1080
1081err_out:
1082	nlmsg_free(msg);
1083out:
1084	rtnl_set_sk_err(net, RTNLGRP_NSID, err);
1085}
1086
1087static int __init net_ns_init(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1088{
1089	struct net_generic *ng;
1090
1091#ifdef CONFIG_NET_NS
 
1092	net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
1093					SMP_CACHE_BYTES,
1094					SLAB_PANIC|SLAB_ACCOUNT, NULL);
1095
1096	/* Create workqueue for cleanup */
1097	netns_wq = create_singlethread_workqueue("netns");
1098	if (!netns_wq)
1099		panic("Could not create netns workq");
1100#endif
1101
1102	ng = net_alloc_generic();
1103	if (!ng)
1104		panic("Could not allocate generic netns");
1105
1106	rcu_assign_pointer(init_net.gen, ng);
1107
 
 
 
 
 
1108	down_write(&pernet_ops_rwsem);
1109	if (setup_net(&init_net, &init_user_ns))
1110		panic("Could not setup the initial network namespace");
1111
1112	init_net_initialized = true;
1113	up_write(&pernet_ops_rwsem);
1114
1115	if (register_pernet_subsys(&net_ns_ops))
1116		panic("Could not register network namespace subsystems");
1117
1118	rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL,
1119		      RTNL_FLAG_DOIT_UNLOCKED);
1120	rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid,
1121		      RTNL_FLAG_DOIT_UNLOCKED);
 
 
 
 
 
 
1122
1123	return 0;
 
 
 
 
 
 
 
1124}
1125
1126pure_initcall(net_ns_init);
1127
1128#ifdef CONFIG_NET_NS
1129static int __register_pernet_operations(struct list_head *list,
1130					struct pernet_operations *ops)
1131{
1132	struct net *net;
1133	int error;
1134	LIST_HEAD(net_exit_list);
1135
1136	list_add_tail(&ops->list, list);
1137	if (ops->init || (ops->id && ops->size)) {
1138		/* We held write locked pernet_ops_rwsem, and parallel
1139		 * setup_net() and cleanup_net() are not possible.
1140		 */
1141		for_each_net(net) {
1142			error = ops_init(ops, net);
1143			if (error)
1144				goto out_undo;
1145			list_add_tail(&net->exit_list, &net_exit_list);
1146		}
1147	}
1148	return 0;
1149
1150out_undo:
1151	/* If I have an error cleanup all namespaces I initialized */
1152	list_del(&ops->list);
1153	ops_pre_exit_list(ops, &net_exit_list);
1154	synchronize_rcu();
1155	ops_exit_list(ops, &net_exit_list);
1156	ops_free_list(ops, &net_exit_list);
1157	return error;
1158}
1159
1160static void __unregister_pernet_operations(struct pernet_operations *ops)
1161{
1162	struct net *net;
1163	LIST_HEAD(net_exit_list);
1164
1165	list_del(&ops->list);
1166	/* See comment in __register_pernet_operations() */
1167	for_each_net(net)
1168		list_add_tail(&net->exit_list, &net_exit_list);
1169	ops_pre_exit_list(ops, &net_exit_list);
1170	synchronize_rcu();
1171	ops_exit_list(ops, &net_exit_list);
1172	ops_free_list(ops, &net_exit_list);
1173}
1174
1175#else
1176
1177static int __register_pernet_operations(struct list_head *list,
1178					struct pernet_operations *ops)
1179{
1180	if (!init_net_initialized) {
1181		list_add_tail(&ops->list, list);
1182		return 0;
1183	}
1184
1185	return ops_init(ops, &init_net);
1186}
1187
1188static void __unregister_pernet_operations(struct pernet_operations *ops)
1189{
1190	if (!init_net_initialized) {
1191		list_del(&ops->list);
1192	} else {
1193		LIST_HEAD(net_exit_list);
1194		list_add(&init_net.exit_list, &net_exit_list);
1195		ops_pre_exit_list(ops, &net_exit_list);
1196		synchronize_rcu();
1197		ops_exit_list(ops, &net_exit_list);
1198		ops_free_list(ops, &net_exit_list);
1199	}
1200}
1201
1202#endif /* CONFIG_NET_NS */
1203
1204static DEFINE_IDA(net_generic_ids);
1205
1206static int register_pernet_operations(struct list_head *list,
1207				      struct pernet_operations *ops)
1208{
1209	int error;
1210
 
 
 
1211	if (ops->id) {
1212		error = ida_alloc_min(&net_generic_ids, MIN_PERNET_OPS_ID,
1213				GFP_KERNEL);
1214		if (error < 0)
1215			return error;
1216		*ops->id = error;
1217		max_gen_ptrs = max(max_gen_ptrs, *ops->id + 1);
 
 
 
 
1218	}
1219	error = __register_pernet_operations(list, ops);
1220	if (error) {
1221		rcu_barrier();
1222		if (ops->id)
1223			ida_free(&net_generic_ids, *ops->id);
1224	}
1225
1226	return error;
1227}
1228
1229static void unregister_pernet_operations(struct pernet_operations *ops)
1230{
1231	__unregister_pernet_operations(ops);
1232	rcu_barrier();
1233	if (ops->id)
1234		ida_free(&net_generic_ids, *ops->id);
1235}
1236
1237/**
1238 *      register_pernet_subsys - register a network namespace subsystem
1239 *	@ops:  pernet operations structure for the subsystem
1240 *
1241 *	Register a subsystem which has init and exit functions
1242 *	that are called when network namespaces are created and
1243 *	destroyed respectively.
1244 *
1245 *	When registered all network namespace init functions are
1246 *	called for every existing network namespace.  Allowing kernel
1247 *	modules to have a race free view of the set of network namespaces.
1248 *
1249 *	When a new network namespace is created all of the init
1250 *	methods are called in the order in which they were registered.
1251 *
1252 *	When a network namespace is destroyed all of the exit methods
1253 *	are called in the reverse of the order with which they were
1254 *	registered.
1255 */
1256int register_pernet_subsys(struct pernet_operations *ops)
1257{
1258	int error;
1259	down_write(&pernet_ops_rwsem);
1260	error =  register_pernet_operations(first_device, ops);
1261	up_write(&pernet_ops_rwsem);
1262	return error;
1263}
1264EXPORT_SYMBOL_GPL(register_pernet_subsys);
1265
1266/**
1267 *      unregister_pernet_subsys - unregister a network namespace subsystem
1268 *	@ops: pernet operations structure to manipulate
1269 *
1270 *	Remove the pernet operations structure from the list to be
1271 *	used when network namespaces are created or destroyed.  In
1272 *	addition run the exit method for all existing network
1273 *	namespaces.
1274 */
1275void unregister_pernet_subsys(struct pernet_operations *ops)
1276{
1277	down_write(&pernet_ops_rwsem);
1278	unregister_pernet_operations(ops);
1279	up_write(&pernet_ops_rwsem);
1280}
1281EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
1282
1283/**
1284 *      register_pernet_device - register a network namespace device
1285 *	@ops:  pernet operations structure for the subsystem
1286 *
1287 *	Register a device which has init and exit functions
1288 *	that are called when network namespaces are created and
1289 *	destroyed respectively.
1290 *
1291 *	When registered all network namespace init functions are
1292 *	called for every existing network namespace.  Allowing kernel
1293 *	modules to have a race free view of the set of network namespaces.
1294 *
1295 *	When a new network namespace is created all of the init
1296 *	methods are called in the order in which they were registered.
1297 *
1298 *	When a network namespace is destroyed all of the exit methods
1299 *	are called in the reverse of the order with which they were
1300 *	registered.
1301 */
1302int register_pernet_device(struct pernet_operations *ops)
1303{
1304	int error;
1305	down_write(&pernet_ops_rwsem);
1306	error = register_pernet_operations(&pernet_list, ops);
1307	if (!error && (first_device == &pernet_list))
1308		first_device = &ops->list;
1309	up_write(&pernet_ops_rwsem);
1310	return error;
1311}
1312EXPORT_SYMBOL_GPL(register_pernet_device);
1313
1314/**
1315 *      unregister_pernet_device - unregister a network namespace netdevice
1316 *	@ops: pernet operations structure to manipulate
1317 *
1318 *	Remove the pernet operations structure from the list to be
1319 *	used when network namespaces are created or destroyed.  In
1320 *	addition run the exit method for all existing network
1321 *	namespaces.
1322 */
1323void unregister_pernet_device(struct pernet_operations *ops)
1324{
1325	down_write(&pernet_ops_rwsem);
1326	if (&ops->list == first_device)
1327		first_device = first_device->next;
1328	unregister_pernet_operations(ops);
1329	up_write(&pernet_ops_rwsem);
1330}
1331EXPORT_SYMBOL_GPL(unregister_pernet_device);
1332
1333#ifdef CONFIG_NET_NS
1334static struct ns_common *netns_get(struct task_struct *task)
1335{
1336	struct net *net = NULL;
1337	struct nsproxy *nsproxy;
1338
1339	task_lock(task);
1340	nsproxy = task->nsproxy;
1341	if (nsproxy)
1342		net = get_net(nsproxy->net_ns);
1343	task_unlock(task);
1344
1345	return net ? &net->ns : NULL;
1346}
1347
1348static inline struct net *to_net_ns(struct ns_common *ns)
1349{
1350	return container_of(ns, struct net, ns);
1351}
1352
1353static void netns_put(struct ns_common *ns)
1354{
1355	put_net(to_net_ns(ns));
1356}
1357
1358static int netns_install(struct nsproxy *nsproxy, struct ns_common *ns)
1359{
 
1360	struct net *net = to_net_ns(ns);
1361
1362	if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
1363	    !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
1364		return -EPERM;
1365
1366	put_net(nsproxy->net_ns);
1367	nsproxy->net_ns = get_net(net);
1368	return 0;
1369}
1370
1371static struct user_namespace *netns_owner(struct ns_common *ns)
1372{
1373	return to_net_ns(ns)->user_ns;
1374}
1375
1376const struct proc_ns_operations netns_operations = {
1377	.name		= "net",
1378	.type		= CLONE_NEWNET,
1379	.get		= netns_get,
1380	.put		= netns_put,
1381	.install	= netns_install,
1382	.owner		= netns_owner,
1383};
1384#endif