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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * NETLINK Kernel-user communication protocol.
4 *
5 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
6 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
7 * Patrick McHardy <kaber@trash.net>
8 *
9 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
10 * added netlink_proto_exit
11 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
12 * use nlk_sk, as sk->protinfo is on a diet 8)
13 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
14 * - inc module use count of module that owns
15 * the kernel socket in case userspace opens
16 * socket of same protocol
17 * - remove all module support, since netlink is
18 * mandatory if CONFIG_NET=y these days
19 */
20
21#include <linux/module.h>
22
23#include <linux/bpf.h>
24#include <linux/capability.h>
25#include <linux/kernel.h>
26#include <linux/filter.h>
27#include <linux/init.h>
28#include <linux/signal.h>
29#include <linux/sched.h>
30#include <linux/errno.h>
31#include <linux/string.h>
32#include <linux/stat.h>
33#include <linux/socket.h>
34#include <linux/un.h>
35#include <linux/fcntl.h>
36#include <linux/termios.h>
37#include <linux/sockios.h>
38#include <linux/net.h>
39#include <linux/fs.h>
40#include <linux/slab.h>
41#include <linux/uaccess.h>
42#include <linux/skbuff.h>
43#include <linux/netdevice.h>
44#include <linux/rtnetlink.h>
45#include <linux/proc_fs.h>
46#include <linux/seq_file.h>
47#include <linux/notifier.h>
48#include <linux/security.h>
49#include <linux/jhash.h>
50#include <linux/jiffies.h>
51#include <linux/random.h>
52#include <linux/bitops.h>
53#include <linux/mm.h>
54#include <linux/types.h>
55#include <linux/audit.h>
56#include <linux/mutex.h>
57#include <linux/vmalloc.h>
58#include <linux/if_arp.h>
59#include <linux/rhashtable.h>
60#include <asm/cacheflush.h>
61#include <linux/hash.h>
62#include <linux/genetlink.h>
63#include <linux/net_namespace.h>
64#include <linux/nospec.h>
65#include <linux/btf_ids.h>
66
67#include <net/net_namespace.h>
68#include <net/netns/generic.h>
69#include <net/sock.h>
70#include <net/scm.h>
71#include <net/netlink.h>
72#define CREATE_TRACE_POINTS
73#include <trace/events/netlink.h>
74
75#include "af_netlink.h"
76
77struct listeners {
78 struct rcu_head rcu;
79 unsigned long masks[];
80};
81
82/* state bits */
83#define NETLINK_S_CONGESTED 0x0
84
85static inline int netlink_is_kernel(struct sock *sk)
86{
87 return nlk_test_bit(KERNEL_SOCKET, sk);
88}
89
90struct netlink_table *nl_table __read_mostly;
91EXPORT_SYMBOL_GPL(nl_table);
92
93static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
94
95static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
96
97static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
98 "nlk_cb_mutex-ROUTE",
99 "nlk_cb_mutex-1",
100 "nlk_cb_mutex-USERSOCK",
101 "nlk_cb_mutex-FIREWALL",
102 "nlk_cb_mutex-SOCK_DIAG",
103 "nlk_cb_mutex-NFLOG",
104 "nlk_cb_mutex-XFRM",
105 "nlk_cb_mutex-SELINUX",
106 "nlk_cb_mutex-ISCSI",
107 "nlk_cb_mutex-AUDIT",
108 "nlk_cb_mutex-FIB_LOOKUP",
109 "nlk_cb_mutex-CONNECTOR",
110 "nlk_cb_mutex-NETFILTER",
111 "nlk_cb_mutex-IP6_FW",
112 "nlk_cb_mutex-DNRTMSG",
113 "nlk_cb_mutex-KOBJECT_UEVENT",
114 "nlk_cb_mutex-GENERIC",
115 "nlk_cb_mutex-17",
116 "nlk_cb_mutex-SCSITRANSPORT",
117 "nlk_cb_mutex-ECRYPTFS",
118 "nlk_cb_mutex-RDMA",
119 "nlk_cb_mutex-CRYPTO",
120 "nlk_cb_mutex-SMC",
121 "nlk_cb_mutex-23",
122 "nlk_cb_mutex-24",
123 "nlk_cb_mutex-25",
124 "nlk_cb_mutex-26",
125 "nlk_cb_mutex-27",
126 "nlk_cb_mutex-28",
127 "nlk_cb_mutex-29",
128 "nlk_cb_mutex-30",
129 "nlk_cb_mutex-31",
130 "nlk_cb_mutex-MAX_LINKS"
131};
132
133static int netlink_dump(struct sock *sk);
134
135/* nl_table locking explained:
136 * Lookup and traversal are protected with an RCU read-side lock. Insertion
137 * and removal are protected with per bucket lock while using RCU list
138 * modification primitives and may run in parallel to RCU protected lookups.
139 * Destruction of the Netlink socket may only occur *after* nl_table_lock has
140 * been acquired * either during or after the socket has been removed from
141 * the list and after an RCU grace period.
142 */
143DEFINE_RWLOCK(nl_table_lock);
144EXPORT_SYMBOL_GPL(nl_table_lock);
145static atomic_t nl_table_users = ATOMIC_INIT(0);
146
147#define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
148
149static BLOCKING_NOTIFIER_HEAD(netlink_chain);
150
151
152static const struct rhashtable_params netlink_rhashtable_params;
153
154void do_trace_netlink_extack(const char *msg)
155{
156 trace_netlink_extack(msg);
157}
158EXPORT_SYMBOL(do_trace_netlink_extack);
159
160static inline u32 netlink_group_mask(u32 group)
161{
162 if (group > 32)
163 return 0;
164 return group ? 1 << (group - 1) : 0;
165}
166
167static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
168 gfp_t gfp_mask)
169{
170 unsigned int len = skb->len;
171 struct sk_buff *new;
172
173 new = alloc_skb(len, gfp_mask);
174 if (new == NULL)
175 return NULL;
176
177 NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
178 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
179 NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
180
181 skb_put_data(new, skb->data, len);
182 return new;
183}
184
185static unsigned int netlink_tap_net_id;
186
187struct netlink_tap_net {
188 struct list_head netlink_tap_all;
189 struct mutex netlink_tap_lock;
190};
191
192int netlink_add_tap(struct netlink_tap *nt)
193{
194 struct net *net = dev_net(nt->dev);
195 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
196
197 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
198 return -EINVAL;
199
200 mutex_lock(&nn->netlink_tap_lock);
201 list_add_rcu(&nt->list, &nn->netlink_tap_all);
202 mutex_unlock(&nn->netlink_tap_lock);
203
204 __module_get(nt->module);
205
206 return 0;
207}
208EXPORT_SYMBOL_GPL(netlink_add_tap);
209
210static int __netlink_remove_tap(struct netlink_tap *nt)
211{
212 struct net *net = dev_net(nt->dev);
213 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
214 bool found = false;
215 struct netlink_tap *tmp;
216
217 mutex_lock(&nn->netlink_tap_lock);
218
219 list_for_each_entry(tmp, &nn->netlink_tap_all, list) {
220 if (nt == tmp) {
221 list_del_rcu(&nt->list);
222 found = true;
223 goto out;
224 }
225 }
226
227 pr_warn("__netlink_remove_tap: %p not found\n", nt);
228out:
229 mutex_unlock(&nn->netlink_tap_lock);
230
231 if (found)
232 module_put(nt->module);
233
234 return found ? 0 : -ENODEV;
235}
236
237int netlink_remove_tap(struct netlink_tap *nt)
238{
239 int ret;
240
241 ret = __netlink_remove_tap(nt);
242 synchronize_net();
243
244 return ret;
245}
246EXPORT_SYMBOL_GPL(netlink_remove_tap);
247
248static __net_init int netlink_tap_init_net(struct net *net)
249{
250 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
251
252 INIT_LIST_HEAD(&nn->netlink_tap_all);
253 mutex_init(&nn->netlink_tap_lock);
254 return 0;
255}
256
257static struct pernet_operations netlink_tap_net_ops = {
258 .init = netlink_tap_init_net,
259 .id = &netlink_tap_net_id,
260 .size = sizeof(struct netlink_tap_net),
261};
262
263static bool netlink_filter_tap(const struct sk_buff *skb)
264{
265 struct sock *sk = skb->sk;
266
267 /* We take the more conservative approach and
268 * whitelist socket protocols that may pass.
269 */
270 switch (sk->sk_protocol) {
271 case NETLINK_ROUTE:
272 case NETLINK_USERSOCK:
273 case NETLINK_SOCK_DIAG:
274 case NETLINK_NFLOG:
275 case NETLINK_XFRM:
276 case NETLINK_FIB_LOOKUP:
277 case NETLINK_NETFILTER:
278 case NETLINK_GENERIC:
279 return true;
280 }
281
282 return false;
283}
284
285static int __netlink_deliver_tap_skb(struct sk_buff *skb,
286 struct net_device *dev)
287{
288 struct sk_buff *nskb;
289 struct sock *sk = skb->sk;
290 int ret = -ENOMEM;
291
292 if (!net_eq(dev_net(dev), sock_net(sk)))
293 return 0;
294
295 dev_hold(dev);
296
297 if (is_vmalloc_addr(skb->head))
298 nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
299 else
300 nskb = skb_clone(skb, GFP_ATOMIC);
301 if (nskb) {
302 nskb->dev = dev;
303 nskb->protocol = htons((u16) sk->sk_protocol);
304 nskb->pkt_type = netlink_is_kernel(sk) ?
305 PACKET_KERNEL : PACKET_USER;
306 skb_reset_network_header(nskb);
307 ret = dev_queue_xmit(nskb);
308 if (unlikely(ret > 0))
309 ret = net_xmit_errno(ret);
310 }
311
312 dev_put(dev);
313 return ret;
314}
315
316static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn)
317{
318 int ret;
319 struct netlink_tap *tmp;
320
321 if (!netlink_filter_tap(skb))
322 return;
323
324 list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) {
325 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
326 if (unlikely(ret))
327 break;
328 }
329}
330
331static void netlink_deliver_tap(struct net *net, struct sk_buff *skb)
332{
333 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
334
335 rcu_read_lock();
336
337 if (unlikely(!list_empty(&nn->netlink_tap_all)))
338 __netlink_deliver_tap(skb, nn);
339
340 rcu_read_unlock();
341}
342
343static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
344 struct sk_buff *skb)
345{
346 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
347 netlink_deliver_tap(sock_net(dst), skb);
348}
349
350static void netlink_overrun(struct sock *sk)
351{
352 if (!nlk_test_bit(RECV_NO_ENOBUFS, sk)) {
353 if (!test_and_set_bit(NETLINK_S_CONGESTED,
354 &nlk_sk(sk)->state)) {
355 WRITE_ONCE(sk->sk_err, ENOBUFS);
356 sk_error_report(sk);
357 }
358 }
359 atomic_inc(&sk->sk_drops);
360}
361
362static void netlink_rcv_wake(struct sock *sk)
363{
364 struct netlink_sock *nlk = nlk_sk(sk);
365
366 if (skb_queue_empty_lockless(&sk->sk_receive_queue))
367 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
368 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
369 wake_up_interruptible(&nlk->wait);
370}
371
372static void netlink_skb_destructor(struct sk_buff *skb)
373{
374 if (is_vmalloc_addr(skb->head)) {
375 if (!skb->cloned ||
376 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
377 vfree_atomic(skb->head);
378
379 skb->head = NULL;
380 }
381 if (skb->sk != NULL)
382 sock_rfree(skb);
383}
384
385static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
386{
387 WARN_ON(skb->sk != NULL);
388 skb->sk = sk;
389 skb->destructor = netlink_skb_destructor;
390 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
391 sk_mem_charge(sk, skb->truesize);
392}
393
394static void netlink_sock_destruct(struct sock *sk)
395{
396 struct netlink_sock *nlk = nlk_sk(sk);
397
398 if (nlk->cb_running) {
399 if (nlk->cb.done)
400 nlk->cb.done(&nlk->cb);
401 module_put(nlk->cb.module);
402 kfree_skb(nlk->cb.skb);
403 }
404
405 skb_queue_purge(&sk->sk_receive_queue);
406
407 if (!sock_flag(sk, SOCK_DEAD)) {
408 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
409 return;
410 }
411
412 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
413 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
414 WARN_ON(nlk_sk(sk)->groups);
415}
416
417static void netlink_sock_destruct_work(struct work_struct *work)
418{
419 struct netlink_sock *nlk = container_of(work, struct netlink_sock,
420 work);
421
422 sk_free(&nlk->sk);
423}
424
425/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
426 * SMP. Look, when several writers sleep and reader wakes them up, all but one
427 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
428 * this, _but_ remember, it adds useless work on UP machines.
429 */
430
431void netlink_table_grab(void)
432 __acquires(nl_table_lock)
433{
434 might_sleep();
435
436 write_lock_irq(&nl_table_lock);
437
438 if (atomic_read(&nl_table_users)) {
439 DECLARE_WAITQUEUE(wait, current);
440
441 add_wait_queue_exclusive(&nl_table_wait, &wait);
442 for (;;) {
443 set_current_state(TASK_UNINTERRUPTIBLE);
444 if (atomic_read(&nl_table_users) == 0)
445 break;
446 write_unlock_irq(&nl_table_lock);
447 schedule();
448 write_lock_irq(&nl_table_lock);
449 }
450
451 __set_current_state(TASK_RUNNING);
452 remove_wait_queue(&nl_table_wait, &wait);
453 }
454}
455
456void netlink_table_ungrab(void)
457 __releases(nl_table_lock)
458{
459 write_unlock_irq(&nl_table_lock);
460 wake_up(&nl_table_wait);
461}
462
463static inline void
464netlink_lock_table(void)
465{
466 unsigned long flags;
467
468 /* read_lock() synchronizes us to netlink_table_grab */
469
470 read_lock_irqsave(&nl_table_lock, flags);
471 atomic_inc(&nl_table_users);
472 read_unlock_irqrestore(&nl_table_lock, flags);
473}
474
475static inline void
476netlink_unlock_table(void)
477{
478 if (atomic_dec_and_test(&nl_table_users))
479 wake_up(&nl_table_wait);
480}
481
482struct netlink_compare_arg
483{
484 possible_net_t pnet;
485 u32 portid;
486};
487
488/* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
489#define netlink_compare_arg_len \
490 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
491
492static inline int netlink_compare(struct rhashtable_compare_arg *arg,
493 const void *ptr)
494{
495 const struct netlink_compare_arg *x = arg->key;
496 const struct netlink_sock *nlk = ptr;
497
498 return nlk->portid != x->portid ||
499 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
500}
501
502static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
503 struct net *net, u32 portid)
504{
505 memset(arg, 0, sizeof(*arg));
506 write_pnet(&arg->pnet, net);
507 arg->portid = portid;
508}
509
510static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
511 struct net *net)
512{
513 struct netlink_compare_arg arg;
514
515 netlink_compare_arg_init(&arg, net, portid);
516 return rhashtable_lookup_fast(&table->hash, &arg,
517 netlink_rhashtable_params);
518}
519
520static int __netlink_insert(struct netlink_table *table, struct sock *sk)
521{
522 struct netlink_compare_arg arg;
523
524 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
525 return rhashtable_lookup_insert_key(&table->hash, &arg,
526 &nlk_sk(sk)->node,
527 netlink_rhashtable_params);
528}
529
530static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
531{
532 struct netlink_table *table = &nl_table[protocol];
533 struct sock *sk;
534
535 rcu_read_lock();
536 sk = __netlink_lookup(table, portid, net);
537 if (sk)
538 sock_hold(sk);
539 rcu_read_unlock();
540
541 return sk;
542}
543
544static const struct proto_ops netlink_ops;
545
546static void
547netlink_update_listeners(struct sock *sk)
548{
549 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
550 unsigned long mask;
551 unsigned int i;
552 struct listeners *listeners;
553
554 listeners = nl_deref_protected(tbl->listeners);
555 if (!listeners)
556 return;
557
558 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
559 mask = 0;
560 sk_for_each_bound(sk, &tbl->mc_list) {
561 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
562 mask |= nlk_sk(sk)->groups[i];
563 }
564 listeners->masks[i] = mask;
565 }
566 /* this function is only called with the netlink table "grabbed", which
567 * makes sure updates are visible before bind or setsockopt return. */
568}
569
570static int netlink_insert(struct sock *sk, u32 portid)
571{
572 struct netlink_table *table = &nl_table[sk->sk_protocol];
573 int err;
574
575 lock_sock(sk);
576
577 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
578 if (nlk_sk(sk)->bound)
579 goto err;
580
581 /* portid can be read locklessly from netlink_getname(). */
582 WRITE_ONCE(nlk_sk(sk)->portid, portid);
583
584 sock_hold(sk);
585
586 err = __netlink_insert(table, sk);
587 if (err) {
588 /* In case the hashtable backend returns with -EBUSY
589 * from here, it must not escape to the caller.
590 */
591 if (unlikely(err == -EBUSY))
592 err = -EOVERFLOW;
593 if (err == -EEXIST)
594 err = -EADDRINUSE;
595 sock_put(sk);
596 goto err;
597 }
598
599 /* We need to ensure that the socket is hashed and visible. */
600 smp_wmb();
601 /* Paired with lockless reads from netlink_bind(),
602 * netlink_connect() and netlink_sendmsg().
603 */
604 WRITE_ONCE(nlk_sk(sk)->bound, portid);
605
606err:
607 release_sock(sk);
608 return err;
609}
610
611static void netlink_remove(struct sock *sk)
612{
613 struct netlink_table *table;
614
615 table = &nl_table[sk->sk_protocol];
616 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
617 netlink_rhashtable_params)) {
618 WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
619 __sock_put(sk);
620 }
621
622 netlink_table_grab();
623 if (nlk_sk(sk)->subscriptions) {
624 __sk_del_bind_node(sk);
625 netlink_update_listeners(sk);
626 }
627 if (sk->sk_protocol == NETLINK_GENERIC)
628 atomic_inc(&genl_sk_destructing_cnt);
629 netlink_table_ungrab();
630}
631
632static struct proto netlink_proto = {
633 .name = "NETLINK",
634 .owner = THIS_MODULE,
635 .obj_size = sizeof(struct netlink_sock),
636};
637
638static int __netlink_create(struct net *net, struct socket *sock,
639 struct mutex *cb_mutex, int protocol,
640 int kern)
641{
642 struct sock *sk;
643 struct netlink_sock *nlk;
644
645 sock->ops = &netlink_ops;
646
647 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
648 if (!sk)
649 return -ENOMEM;
650
651 sock_init_data(sock, sk);
652
653 nlk = nlk_sk(sk);
654 if (cb_mutex) {
655 nlk->cb_mutex = cb_mutex;
656 } else {
657 nlk->cb_mutex = &nlk->cb_def_mutex;
658 mutex_init(nlk->cb_mutex);
659 lockdep_set_class_and_name(nlk->cb_mutex,
660 nlk_cb_mutex_keys + protocol,
661 nlk_cb_mutex_key_strings[protocol]);
662 }
663 init_waitqueue_head(&nlk->wait);
664
665 sk->sk_destruct = netlink_sock_destruct;
666 sk->sk_protocol = protocol;
667 return 0;
668}
669
670static int netlink_create(struct net *net, struct socket *sock, int protocol,
671 int kern)
672{
673 struct module *module = NULL;
674 struct mutex *cb_mutex;
675 struct netlink_sock *nlk;
676 int (*bind)(struct net *net, int group);
677 void (*unbind)(struct net *net, int group);
678 void (*release)(struct sock *sock, unsigned long *groups);
679 int err = 0;
680
681 sock->state = SS_UNCONNECTED;
682
683 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
684 return -ESOCKTNOSUPPORT;
685
686 if (protocol < 0 || protocol >= MAX_LINKS)
687 return -EPROTONOSUPPORT;
688 protocol = array_index_nospec(protocol, MAX_LINKS);
689
690 netlink_lock_table();
691#ifdef CONFIG_MODULES
692 if (!nl_table[protocol].registered) {
693 netlink_unlock_table();
694 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
695 netlink_lock_table();
696 }
697#endif
698 if (nl_table[protocol].registered &&
699 try_module_get(nl_table[protocol].module))
700 module = nl_table[protocol].module;
701 else
702 err = -EPROTONOSUPPORT;
703 cb_mutex = nl_table[protocol].cb_mutex;
704 bind = nl_table[protocol].bind;
705 unbind = nl_table[protocol].unbind;
706 release = nl_table[protocol].release;
707 netlink_unlock_table();
708
709 if (err < 0)
710 goto out;
711
712 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
713 if (err < 0)
714 goto out_module;
715
716 sock_prot_inuse_add(net, &netlink_proto, 1);
717
718 nlk = nlk_sk(sock->sk);
719 nlk->module = module;
720 nlk->netlink_bind = bind;
721 nlk->netlink_unbind = unbind;
722 nlk->netlink_release = release;
723out:
724 return err;
725
726out_module:
727 module_put(module);
728 goto out;
729}
730
731static void deferred_put_nlk_sk(struct rcu_head *head)
732{
733 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
734 struct sock *sk = &nlk->sk;
735
736 kfree(nlk->groups);
737 nlk->groups = NULL;
738
739 if (!refcount_dec_and_test(&sk->sk_refcnt))
740 return;
741
742 if (nlk->cb_running && nlk->cb.done) {
743 INIT_WORK(&nlk->work, netlink_sock_destruct_work);
744 schedule_work(&nlk->work);
745 return;
746 }
747
748 sk_free(sk);
749}
750
751static int netlink_release(struct socket *sock)
752{
753 struct sock *sk = sock->sk;
754 struct netlink_sock *nlk;
755
756 if (!sk)
757 return 0;
758
759 netlink_remove(sk);
760 sock_orphan(sk);
761 nlk = nlk_sk(sk);
762
763 /*
764 * OK. Socket is unlinked, any packets that arrive now
765 * will be purged.
766 */
767 if (nlk->netlink_release)
768 nlk->netlink_release(sk, nlk->groups);
769
770 /* must not acquire netlink_table_lock in any way again before unbind
771 * and notifying genetlink is done as otherwise it might deadlock
772 */
773 if (nlk->netlink_unbind) {
774 int i;
775
776 for (i = 0; i < nlk->ngroups; i++)
777 if (test_bit(i, nlk->groups))
778 nlk->netlink_unbind(sock_net(sk), i + 1);
779 }
780 if (sk->sk_protocol == NETLINK_GENERIC &&
781 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
782 wake_up(&genl_sk_destructing_waitq);
783
784 sock->sk = NULL;
785 wake_up_interruptible_all(&nlk->wait);
786
787 skb_queue_purge(&sk->sk_write_queue);
788
789 if (nlk->portid && nlk->bound) {
790 struct netlink_notify n = {
791 .net = sock_net(sk),
792 .protocol = sk->sk_protocol,
793 .portid = nlk->portid,
794 };
795 blocking_notifier_call_chain(&netlink_chain,
796 NETLINK_URELEASE, &n);
797 }
798
799 module_put(nlk->module);
800
801 if (netlink_is_kernel(sk)) {
802 netlink_table_grab();
803 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
804 if (--nl_table[sk->sk_protocol].registered == 0) {
805 struct listeners *old;
806
807 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
808 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
809 kfree_rcu(old, rcu);
810 nl_table[sk->sk_protocol].module = NULL;
811 nl_table[sk->sk_protocol].bind = NULL;
812 nl_table[sk->sk_protocol].unbind = NULL;
813 nl_table[sk->sk_protocol].flags = 0;
814 nl_table[sk->sk_protocol].registered = 0;
815 }
816 netlink_table_ungrab();
817 }
818
819 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
820
821 /* Because struct net might disappear soon, do not keep a pointer. */
822 if (!sk->sk_net_refcnt && sock_net(sk) != &init_net) {
823 __netns_tracker_free(sock_net(sk), &sk->ns_tracker, false);
824 /* Because of deferred_put_nlk_sk and use of work queue,
825 * it is possible netns will be freed before this socket.
826 */
827 sock_net_set(sk, &init_net);
828 __netns_tracker_alloc(&init_net, &sk->ns_tracker,
829 false, GFP_KERNEL);
830 }
831 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
832 return 0;
833}
834
835static int netlink_autobind(struct socket *sock)
836{
837 struct sock *sk = sock->sk;
838 struct net *net = sock_net(sk);
839 struct netlink_table *table = &nl_table[sk->sk_protocol];
840 s32 portid = task_tgid_vnr(current);
841 int err;
842 s32 rover = -4096;
843 bool ok;
844
845retry:
846 cond_resched();
847 rcu_read_lock();
848 ok = !__netlink_lookup(table, portid, net);
849 rcu_read_unlock();
850 if (!ok) {
851 /* Bind collision, search negative portid values. */
852 if (rover == -4096)
853 /* rover will be in range [S32_MIN, -4097] */
854 rover = S32_MIN + get_random_u32_below(-4096 - S32_MIN);
855 else if (rover >= -4096)
856 rover = -4097;
857 portid = rover--;
858 goto retry;
859 }
860
861 err = netlink_insert(sk, portid);
862 if (err == -EADDRINUSE)
863 goto retry;
864
865 /* If 2 threads race to autobind, that is fine. */
866 if (err == -EBUSY)
867 err = 0;
868
869 return err;
870}
871
872/**
873 * __netlink_ns_capable - General netlink message capability test
874 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
875 * @user_ns: The user namespace of the capability to use
876 * @cap: The capability to use
877 *
878 * Test to see if the opener of the socket we received the message
879 * from had when the netlink socket was created and the sender of the
880 * message has the capability @cap in the user namespace @user_ns.
881 */
882bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
883 struct user_namespace *user_ns, int cap)
884{
885 return ((nsp->flags & NETLINK_SKB_DST) ||
886 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
887 ns_capable(user_ns, cap);
888}
889EXPORT_SYMBOL(__netlink_ns_capable);
890
891/**
892 * netlink_ns_capable - General netlink message capability test
893 * @skb: socket buffer holding a netlink command from userspace
894 * @user_ns: The user namespace of the capability to use
895 * @cap: The capability to use
896 *
897 * Test to see if the opener of the socket we received the message
898 * from had when the netlink socket was created and the sender of the
899 * message has the capability @cap in the user namespace @user_ns.
900 */
901bool netlink_ns_capable(const struct sk_buff *skb,
902 struct user_namespace *user_ns, int cap)
903{
904 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
905}
906EXPORT_SYMBOL(netlink_ns_capable);
907
908/**
909 * netlink_capable - Netlink global message capability test
910 * @skb: socket buffer holding a netlink command from userspace
911 * @cap: The capability to use
912 *
913 * Test to see if the opener of the socket we received the message
914 * from had when the netlink socket was created and the sender of the
915 * message has the capability @cap in all user namespaces.
916 */
917bool netlink_capable(const struct sk_buff *skb, int cap)
918{
919 return netlink_ns_capable(skb, &init_user_ns, cap);
920}
921EXPORT_SYMBOL(netlink_capable);
922
923/**
924 * netlink_net_capable - Netlink network namespace message capability test
925 * @skb: socket buffer holding a netlink command from userspace
926 * @cap: The capability to use
927 *
928 * Test to see if the opener of the socket we received the message
929 * from had when the netlink socket was created and the sender of the
930 * message has the capability @cap over the network namespace of
931 * the socket we received the message from.
932 */
933bool netlink_net_capable(const struct sk_buff *skb, int cap)
934{
935 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
936}
937EXPORT_SYMBOL(netlink_net_capable);
938
939static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
940{
941 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
942 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
943}
944
945static void
946netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
947{
948 struct netlink_sock *nlk = nlk_sk(sk);
949
950 if (nlk->subscriptions && !subscriptions)
951 __sk_del_bind_node(sk);
952 else if (!nlk->subscriptions && subscriptions)
953 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
954 nlk->subscriptions = subscriptions;
955}
956
957static int netlink_realloc_groups(struct sock *sk)
958{
959 struct netlink_sock *nlk = nlk_sk(sk);
960 unsigned int groups;
961 unsigned long *new_groups;
962 int err = 0;
963
964 netlink_table_grab();
965
966 groups = nl_table[sk->sk_protocol].groups;
967 if (!nl_table[sk->sk_protocol].registered) {
968 err = -ENOENT;
969 goto out_unlock;
970 }
971
972 if (nlk->ngroups >= groups)
973 goto out_unlock;
974
975 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
976 if (new_groups == NULL) {
977 err = -ENOMEM;
978 goto out_unlock;
979 }
980 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
981 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
982
983 nlk->groups = new_groups;
984 nlk->ngroups = groups;
985 out_unlock:
986 netlink_table_ungrab();
987 return err;
988}
989
990static void netlink_undo_bind(int group, long unsigned int groups,
991 struct sock *sk)
992{
993 struct netlink_sock *nlk = nlk_sk(sk);
994 int undo;
995
996 if (!nlk->netlink_unbind)
997 return;
998
999 for (undo = 0; undo < group; undo++)
1000 if (test_bit(undo, &groups))
1001 nlk->netlink_unbind(sock_net(sk), undo + 1);
1002}
1003
1004static int netlink_bind(struct socket *sock, struct sockaddr *addr,
1005 int addr_len)
1006{
1007 struct sock *sk = sock->sk;
1008 struct net *net = sock_net(sk);
1009 struct netlink_sock *nlk = nlk_sk(sk);
1010 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1011 int err = 0;
1012 unsigned long groups;
1013 bool bound;
1014
1015 if (addr_len < sizeof(struct sockaddr_nl))
1016 return -EINVAL;
1017
1018 if (nladdr->nl_family != AF_NETLINK)
1019 return -EINVAL;
1020 groups = nladdr->nl_groups;
1021
1022 /* Only superuser is allowed to listen multicasts */
1023 if (groups) {
1024 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1025 return -EPERM;
1026 err = netlink_realloc_groups(sk);
1027 if (err)
1028 return err;
1029 }
1030
1031 if (nlk->ngroups < BITS_PER_LONG)
1032 groups &= (1UL << nlk->ngroups) - 1;
1033
1034 /* Paired with WRITE_ONCE() in netlink_insert() */
1035 bound = READ_ONCE(nlk->bound);
1036 if (bound) {
1037 /* Ensure nlk->portid is up-to-date. */
1038 smp_rmb();
1039
1040 if (nladdr->nl_pid != nlk->portid)
1041 return -EINVAL;
1042 }
1043
1044 if (nlk->netlink_bind && groups) {
1045 int group;
1046
1047 /* nl_groups is a u32, so cap the maximum groups we can bind */
1048 for (group = 0; group < BITS_PER_TYPE(u32); group++) {
1049 if (!test_bit(group, &groups))
1050 continue;
1051 err = nlk->netlink_bind(net, group + 1);
1052 if (!err)
1053 continue;
1054 netlink_undo_bind(group, groups, sk);
1055 return err;
1056 }
1057 }
1058
1059 /* No need for barriers here as we return to user-space without
1060 * using any of the bound attributes.
1061 */
1062 netlink_lock_table();
1063 if (!bound) {
1064 err = nladdr->nl_pid ?
1065 netlink_insert(sk, nladdr->nl_pid) :
1066 netlink_autobind(sock);
1067 if (err) {
1068 netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk);
1069 goto unlock;
1070 }
1071 }
1072
1073 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1074 goto unlock;
1075 netlink_unlock_table();
1076
1077 netlink_table_grab();
1078 netlink_update_subscriptions(sk, nlk->subscriptions +
1079 hweight32(groups) -
1080 hweight32(nlk->groups[0]));
1081 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1082 netlink_update_listeners(sk);
1083 netlink_table_ungrab();
1084
1085 return 0;
1086
1087unlock:
1088 netlink_unlock_table();
1089 return err;
1090}
1091
1092static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1093 int alen, int flags)
1094{
1095 int err = 0;
1096 struct sock *sk = sock->sk;
1097 struct netlink_sock *nlk = nlk_sk(sk);
1098 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1099
1100 if (alen < sizeof(addr->sa_family))
1101 return -EINVAL;
1102
1103 if (addr->sa_family == AF_UNSPEC) {
1104 /* paired with READ_ONCE() in netlink_getsockbyportid() */
1105 WRITE_ONCE(sk->sk_state, NETLINK_UNCONNECTED);
1106 /* dst_portid and dst_group can be read locklessly */
1107 WRITE_ONCE(nlk->dst_portid, 0);
1108 WRITE_ONCE(nlk->dst_group, 0);
1109 return 0;
1110 }
1111 if (addr->sa_family != AF_NETLINK)
1112 return -EINVAL;
1113
1114 if (alen < sizeof(struct sockaddr_nl))
1115 return -EINVAL;
1116
1117 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1118 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1119 return -EPERM;
1120
1121 /* No need for barriers here as we return to user-space without
1122 * using any of the bound attributes.
1123 * Paired with WRITE_ONCE() in netlink_insert().
1124 */
1125 if (!READ_ONCE(nlk->bound))
1126 err = netlink_autobind(sock);
1127
1128 if (err == 0) {
1129 /* paired with READ_ONCE() in netlink_getsockbyportid() */
1130 WRITE_ONCE(sk->sk_state, NETLINK_CONNECTED);
1131 /* dst_portid and dst_group can be read locklessly */
1132 WRITE_ONCE(nlk->dst_portid, nladdr->nl_pid);
1133 WRITE_ONCE(nlk->dst_group, ffs(nladdr->nl_groups));
1134 }
1135
1136 return err;
1137}
1138
1139static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1140 int peer)
1141{
1142 struct sock *sk = sock->sk;
1143 struct netlink_sock *nlk = nlk_sk(sk);
1144 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1145
1146 nladdr->nl_family = AF_NETLINK;
1147 nladdr->nl_pad = 0;
1148
1149 if (peer) {
1150 /* Paired with WRITE_ONCE() in netlink_connect() */
1151 nladdr->nl_pid = READ_ONCE(nlk->dst_portid);
1152 nladdr->nl_groups = netlink_group_mask(READ_ONCE(nlk->dst_group));
1153 } else {
1154 /* Paired with WRITE_ONCE() in netlink_insert() */
1155 nladdr->nl_pid = READ_ONCE(nlk->portid);
1156 netlink_lock_table();
1157 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1158 netlink_unlock_table();
1159 }
1160 return sizeof(*nladdr);
1161}
1162
1163static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1164 unsigned long arg)
1165{
1166 /* try to hand this ioctl down to the NIC drivers.
1167 */
1168 return -ENOIOCTLCMD;
1169}
1170
1171static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1172{
1173 struct sock *sock;
1174 struct netlink_sock *nlk;
1175
1176 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1177 if (!sock)
1178 return ERR_PTR(-ECONNREFUSED);
1179
1180 /* Don't bother queuing skb if kernel socket has no input function */
1181 nlk = nlk_sk(sock);
1182 /* dst_portid and sk_state can be changed in netlink_connect() */
1183 if (READ_ONCE(sock->sk_state) == NETLINK_CONNECTED &&
1184 READ_ONCE(nlk->dst_portid) != nlk_sk(ssk)->portid) {
1185 sock_put(sock);
1186 return ERR_PTR(-ECONNREFUSED);
1187 }
1188 return sock;
1189}
1190
1191struct sock *netlink_getsockbyfilp(struct file *filp)
1192{
1193 struct inode *inode = file_inode(filp);
1194 struct sock *sock;
1195
1196 if (!S_ISSOCK(inode->i_mode))
1197 return ERR_PTR(-ENOTSOCK);
1198
1199 sock = SOCKET_I(inode)->sk;
1200 if (sock->sk_family != AF_NETLINK)
1201 return ERR_PTR(-EINVAL);
1202
1203 sock_hold(sock);
1204 return sock;
1205}
1206
1207struct sk_buff *netlink_alloc_large_skb(unsigned int size, int broadcast)
1208{
1209 struct sk_buff *skb;
1210 void *data;
1211
1212 if (size <= NLMSG_GOODSIZE || broadcast)
1213 return alloc_skb(size, GFP_KERNEL);
1214
1215 size = SKB_DATA_ALIGN(size) +
1216 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1217
1218 data = vmalloc(size);
1219 if (data == NULL)
1220 return NULL;
1221
1222 skb = __build_skb(data, size);
1223 if (skb == NULL)
1224 vfree(data);
1225 else
1226 skb->destructor = netlink_skb_destructor;
1227
1228 return skb;
1229}
1230
1231/*
1232 * Attach a skb to a netlink socket.
1233 * The caller must hold a reference to the destination socket. On error, the
1234 * reference is dropped. The skb is not send to the destination, just all
1235 * all error checks are performed and memory in the queue is reserved.
1236 * Return values:
1237 * < 0: error. skb freed, reference to sock dropped.
1238 * 0: continue
1239 * 1: repeat lookup - reference dropped while waiting for socket memory.
1240 */
1241int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1242 long *timeo, struct sock *ssk)
1243{
1244 struct netlink_sock *nlk;
1245
1246 nlk = nlk_sk(sk);
1247
1248 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1249 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1250 DECLARE_WAITQUEUE(wait, current);
1251 if (!*timeo) {
1252 if (!ssk || netlink_is_kernel(ssk))
1253 netlink_overrun(sk);
1254 sock_put(sk);
1255 kfree_skb(skb);
1256 return -EAGAIN;
1257 }
1258
1259 __set_current_state(TASK_INTERRUPTIBLE);
1260 add_wait_queue(&nlk->wait, &wait);
1261
1262 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1263 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1264 !sock_flag(sk, SOCK_DEAD))
1265 *timeo = schedule_timeout(*timeo);
1266
1267 __set_current_state(TASK_RUNNING);
1268 remove_wait_queue(&nlk->wait, &wait);
1269 sock_put(sk);
1270
1271 if (signal_pending(current)) {
1272 kfree_skb(skb);
1273 return sock_intr_errno(*timeo);
1274 }
1275 return 1;
1276 }
1277 netlink_skb_set_owner_r(skb, sk);
1278 return 0;
1279}
1280
1281static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1282{
1283 int len = skb->len;
1284
1285 netlink_deliver_tap(sock_net(sk), skb);
1286
1287 skb_queue_tail(&sk->sk_receive_queue, skb);
1288 sk->sk_data_ready(sk);
1289 return len;
1290}
1291
1292int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1293{
1294 int len = __netlink_sendskb(sk, skb);
1295
1296 sock_put(sk);
1297 return len;
1298}
1299
1300void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1301{
1302 kfree_skb(skb);
1303 sock_put(sk);
1304}
1305
1306static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1307{
1308 int delta;
1309
1310 WARN_ON(skb->sk != NULL);
1311 delta = skb->end - skb->tail;
1312 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1313 return skb;
1314
1315 if (skb_shared(skb)) {
1316 struct sk_buff *nskb = skb_clone(skb, allocation);
1317 if (!nskb)
1318 return skb;
1319 consume_skb(skb);
1320 skb = nskb;
1321 }
1322
1323 pskb_expand_head(skb, 0, -delta,
1324 (allocation & ~__GFP_DIRECT_RECLAIM) |
1325 __GFP_NOWARN | __GFP_NORETRY);
1326 return skb;
1327}
1328
1329static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1330 struct sock *ssk)
1331{
1332 int ret;
1333 struct netlink_sock *nlk = nlk_sk(sk);
1334
1335 ret = -ECONNREFUSED;
1336 if (nlk->netlink_rcv != NULL) {
1337 ret = skb->len;
1338 netlink_skb_set_owner_r(skb, sk);
1339 NETLINK_CB(skb).sk = ssk;
1340 netlink_deliver_tap_kernel(sk, ssk, skb);
1341 nlk->netlink_rcv(skb);
1342 consume_skb(skb);
1343 } else {
1344 kfree_skb(skb);
1345 }
1346 sock_put(sk);
1347 return ret;
1348}
1349
1350int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1351 u32 portid, int nonblock)
1352{
1353 struct sock *sk;
1354 int err;
1355 long timeo;
1356
1357 skb = netlink_trim(skb, gfp_any());
1358
1359 timeo = sock_sndtimeo(ssk, nonblock);
1360retry:
1361 sk = netlink_getsockbyportid(ssk, portid);
1362 if (IS_ERR(sk)) {
1363 kfree_skb(skb);
1364 return PTR_ERR(sk);
1365 }
1366 if (netlink_is_kernel(sk))
1367 return netlink_unicast_kernel(sk, skb, ssk);
1368
1369 if (sk_filter(sk, skb)) {
1370 err = skb->len;
1371 kfree_skb(skb);
1372 sock_put(sk);
1373 return err;
1374 }
1375
1376 err = netlink_attachskb(sk, skb, &timeo, ssk);
1377 if (err == 1)
1378 goto retry;
1379 if (err)
1380 return err;
1381
1382 return netlink_sendskb(sk, skb);
1383}
1384EXPORT_SYMBOL(netlink_unicast);
1385
1386int netlink_has_listeners(struct sock *sk, unsigned int group)
1387{
1388 int res = 0;
1389 struct listeners *listeners;
1390
1391 BUG_ON(!netlink_is_kernel(sk));
1392
1393 rcu_read_lock();
1394 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1395
1396 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1397 res = test_bit(group - 1, listeners->masks);
1398
1399 rcu_read_unlock();
1400
1401 return res;
1402}
1403EXPORT_SYMBOL_GPL(netlink_has_listeners);
1404
1405bool netlink_strict_get_check(struct sk_buff *skb)
1406{
1407 return nlk_test_bit(STRICT_CHK, NETLINK_CB(skb).sk);
1408}
1409EXPORT_SYMBOL_GPL(netlink_strict_get_check);
1410
1411static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1412{
1413 struct netlink_sock *nlk = nlk_sk(sk);
1414
1415 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1416 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1417 netlink_skb_set_owner_r(skb, sk);
1418 __netlink_sendskb(sk, skb);
1419 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1420 }
1421 return -1;
1422}
1423
1424struct netlink_broadcast_data {
1425 struct sock *exclude_sk;
1426 struct net *net;
1427 u32 portid;
1428 u32 group;
1429 int failure;
1430 int delivery_failure;
1431 int congested;
1432 int delivered;
1433 gfp_t allocation;
1434 struct sk_buff *skb, *skb2;
1435 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1436 void *tx_data;
1437};
1438
1439static void do_one_broadcast(struct sock *sk,
1440 struct netlink_broadcast_data *p)
1441{
1442 struct netlink_sock *nlk = nlk_sk(sk);
1443 int val;
1444
1445 if (p->exclude_sk == sk)
1446 return;
1447
1448 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1449 !test_bit(p->group - 1, nlk->groups))
1450 return;
1451
1452 if (!net_eq(sock_net(sk), p->net)) {
1453 if (!nlk_test_bit(LISTEN_ALL_NSID, sk))
1454 return;
1455
1456 if (!peernet_has_id(sock_net(sk), p->net))
1457 return;
1458
1459 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1460 CAP_NET_BROADCAST))
1461 return;
1462 }
1463
1464 if (p->failure) {
1465 netlink_overrun(sk);
1466 return;
1467 }
1468
1469 sock_hold(sk);
1470 if (p->skb2 == NULL) {
1471 if (skb_shared(p->skb)) {
1472 p->skb2 = skb_clone(p->skb, p->allocation);
1473 } else {
1474 p->skb2 = skb_get(p->skb);
1475 /*
1476 * skb ownership may have been set when
1477 * delivered to a previous socket.
1478 */
1479 skb_orphan(p->skb2);
1480 }
1481 }
1482 if (p->skb2 == NULL) {
1483 netlink_overrun(sk);
1484 /* Clone failed. Notify ALL listeners. */
1485 p->failure = 1;
1486 if (nlk_test_bit(BROADCAST_SEND_ERROR, sk))
1487 p->delivery_failure = 1;
1488 goto out;
1489 }
1490
1491 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1492 kfree_skb(p->skb2);
1493 p->skb2 = NULL;
1494 goto out;
1495 }
1496
1497 if (sk_filter(sk, p->skb2)) {
1498 kfree_skb(p->skb2);
1499 p->skb2 = NULL;
1500 goto out;
1501 }
1502 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1503 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
1504 NETLINK_CB(p->skb2).nsid_is_set = true;
1505 val = netlink_broadcast_deliver(sk, p->skb2);
1506 if (val < 0) {
1507 netlink_overrun(sk);
1508 if (nlk_test_bit(BROADCAST_SEND_ERROR, sk))
1509 p->delivery_failure = 1;
1510 } else {
1511 p->congested |= val;
1512 p->delivered = 1;
1513 p->skb2 = NULL;
1514 }
1515out:
1516 sock_put(sk);
1517}
1518
1519int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
1520 u32 portid,
1521 u32 group, gfp_t allocation,
1522 netlink_filter_fn filter,
1523 void *filter_data)
1524{
1525 struct net *net = sock_net(ssk);
1526 struct netlink_broadcast_data info;
1527 struct sock *sk;
1528
1529 skb = netlink_trim(skb, allocation);
1530
1531 info.exclude_sk = ssk;
1532 info.net = net;
1533 info.portid = portid;
1534 info.group = group;
1535 info.failure = 0;
1536 info.delivery_failure = 0;
1537 info.congested = 0;
1538 info.delivered = 0;
1539 info.allocation = allocation;
1540 info.skb = skb;
1541 info.skb2 = NULL;
1542 info.tx_filter = filter;
1543 info.tx_data = filter_data;
1544
1545 /* While we sleep in clone, do not allow to change socket list */
1546
1547 netlink_lock_table();
1548
1549 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1550 do_one_broadcast(sk, &info);
1551
1552 consume_skb(skb);
1553
1554 netlink_unlock_table();
1555
1556 if (info.delivery_failure) {
1557 kfree_skb(info.skb2);
1558 return -ENOBUFS;
1559 }
1560 consume_skb(info.skb2);
1561
1562 if (info.delivered) {
1563 if (info.congested && gfpflags_allow_blocking(allocation))
1564 yield();
1565 return 0;
1566 }
1567 return -ESRCH;
1568}
1569EXPORT_SYMBOL(netlink_broadcast_filtered);
1570
1571int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1572 u32 group, gfp_t allocation)
1573{
1574 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1575 NULL, NULL);
1576}
1577EXPORT_SYMBOL(netlink_broadcast);
1578
1579struct netlink_set_err_data {
1580 struct sock *exclude_sk;
1581 u32 portid;
1582 u32 group;
1583 int code;
1584};
1585
1586static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1587{
1588 struct netlink_sock *nlk = nlk_sk(sk);
1589 int ret = 0;
1590
1591 if (sk == p->exclude_sk)
1592 goto out;
1593
1594 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1595 goto out;
1596
1597 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1598 !test_bit(p->group - 1, nlk->groups))
1599 goto out;
1600
1601 if (p->code == ENOBUFS && nlk_test_bit(RECV_NO_ENOBUFS, sk)) {
1602 ret = 1;
1603 goto out;
1604 }
1605
1606 WRITE_ONCE(sk->sk_err, p->code);
1607 sk_error_report(sk);
1608out:
1609 return ret;
1610}
1611
1612/**
1613 * netlink_set_err - report error to broadcast listeners
1614 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1615 * @portid: the PORTID of a process that we want to skip (if any)
1616 * @group: the broadcast group that will notice the error
1617 * @code: error code, must be negative (as usual in kernelspace)
1618 *
1619 * This function returns the number of broadcast listeners that have set the
1620 * NETLINK_NO_ENOBUFS socket option.
1621 */
1622int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1623{
1624 struct netlink_set_err_data info;
1625 unsigned long flags;
1626 struct sock *sk;
1627 int ret = 0;
1628
1629 info.exclude_sk = ssk;
1630 info.portid = portid;
1631 info.group = group;
1632 /* sk->sk_err wants a positive error value */
1633 info.code = -code;
1634
1635 read_lock_irqsave(&nl_table_lock, flags);
1636
1637 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1638 ret += do_one_set_err(sk, &info);
1639
1640 read_unlock_irqrestore(&nl_table_lock, flags);
1641 return ret;
1642}
1643EXPORT_SYMBOL(netlink_set_err);
1644
1645/* must be called with netlink table grabbed */
1646static void netlink_update_socket_mc(struct netlink_sock *nlk,
1647 unsigned int group,
1648 int is_new)
1649{
1650 int old, new = !!is_new, subscriptions;
1651
1652 old = test_bit(group - 1, nlk->groups);
1653 subscriptions = nlk->subscriptions - old + new;
1654 __assign_bit(group - 1, nlk->groups, new);
1655 netlink_update_subscriptions(&nlk->sk, subscriptions);
1656 netlink_update_listeners(&nlk->sk);
1657}
1658
1659static int netlink_setsockopt(struct socket *sock, int level, int optname,
1660 sockptr_t optval, unsigned int optlen)
1661{
1662 struct sock *sk = sock->sk;
1663 struct netlink_sock *nlk = nlk_sk(sk);
1664 unsigned int val = 0;
1665 int nr = -1;
1666
1667 if (level != SOL_NETLINK)
1668 return -ENOPROTOOPT;
1669
1670 if (optlen >= sizeof(int) &&
1671 copy_from_sockptr(&val, optval, sizeof(val)))
1672 return -EFAULT;
1673
1674 switch (optname) {
1675 case NETLINK_PKTINFO:
1676 nr = NETLINK_F_RECV_PKTINFO;
1677 break;
1678 case NETLINK_ADD_MEMBERSHIP:
1679 case NETLINK_DROP_MEMBERSHIP: {
1680 int err;
1681
1682 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1683 return -EPERM;
1684 err = netlink_realloc_groups(sk);
1685 if (err)
1686 return err;
1687 if (!val || val - 1 >= nlk->ngroups)
1688 return -EINVAL;
1689 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1690 err = nlk->netlink_bind(sock_net(sk), val);
1691 if (err)
1692 return err;
1693 }
1694 netlink_table_grab();
1695 netlink_update_socket_mc(nlk, val,
1696 optname == NETLINK_ADD_MEMBERSHIP);
1697 netlink_table_ungrab();
1698 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1699 nlk->netlink_unbind(sock_net(sk), val);
1700
1701 break;
1702 }
1703 case NETLINK_BROADCAST_ERROR:
1704 nr = NETLINK_F_BROADCAST_SEND_ERROR;
1705 break;
1706 case NETLINK_NO_ENOBUFS:
1707 assign_bit(NETLINK_F_RECV_NO_ENOBUFS, &nlk->flags, val);
1708 if (val) {
1709 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1710 wake_up_interruptible(&nlk->wait);
1711 }
1712 break;
1713 case NETLINK_LISTEN_ALL_NSID:
1714 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1715 return -EPERM;
1716 nr = NETLINK_F_LISTEN_ALL_NSID;
1717 break;
1718 case NETLINK_CAP_ACK:
1719 nr = NETLINK_F_CAP_ACK;
1720 break;
1721 case NETLINK_EXT_ACK:
1722 nr = NETLINK_F_EXT_ACK;
1723 break;
1724 case NETLINK_GET_STRICT_CHK:
1725 nr = NETLINK_F_STRICT_CHK;
1726 break;
1727 default:
1728 return -ENOPROTOOPT;
1729 }
1730 if (nr >= 0)
1731 assign_bit(nr, &nlk->flags, val);
1732 return 0;
1733}
1734
1735static int netlink_getsockopt(struct socket *sock, int level, int optname,
1736 char __user *optval, int __user *optlen)
1737{
1738 struct sock *sk = sock->sk;
1739 struct netlink_sock *nlk = nlk_sk(sk);
1740 unsigned int flag;
1741 int len, val;
1742
1743 if (level != SOL_NETLINK)
1744 return -ENOPROTOOPT;
1745
1746 if (get_user(len, optlen))
1747 return -EFAULT;
1748 if (len < 0)
1749 return -EINVAL;
1750
1751 switch (optname) {
1752 case NETLINK_PKTINFO:
1753 flag = NETLINK_F_RECV_PKTINFO;
1754 break;
1755 case NETLINK_BROADCAST_ERROR:
1756 flag = NETLINK_F_BROADCAST_SEND_ERROR;
1757 break;
1758 case NETLINK_NO_ENOBUFS:
1759 flag = NETLINK_F_RECV_NO_ENOBUFS;
1760 break;
1761 case NETLINK_LIST_MEMBERSHIPS: {
1762 int pos, idx, shift, err = 0;
1763
1764 netlink_lock_table();
1765 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1766 if (len - pos < sizeof(u32))
1767 break;
1768
1769 idx = pos / sizeof(unsigned long);
1770 shift = (pos % sizeof(unsigned long)) * 8;
1771 if (put_user((u32)(nlk->groups[idx] >> shift),
1772 (u32 __user *)(optval + pos))) {
1773 err = -EFAULT;
1774 break;
1775 }
1776 }
1777 if (put_user(ALIGN(BITS_TO_BYTES(nlk->ngroups), sizeof(u32)), optlen))
1778 err = -EFAULT;
1779 netlink_unlock_table();
1780 return err;
1781 }
1782 case NETLINK_CAP_ACK:
1783 flag = NETLINK_F_CAP_ACK;
1784 break;
1785 case NETLINK_EXT_ACK:
1786 flag = NETLINK_F_EXT_ACK;
1787 break;
1788 case NETLINK_GET_STRICT_CHK:
1789 flag = NETLINK_F_STRICT_CHK;
1790 break;
1791 default:
1792 return -ENOPROTOOPT;
1793 }
1794
1795 if (len < sizeof(int))
1796 return -EINVAL;
1797
1798 len = sizeof(int);
1799 val = test_bit(flag, &nlk->flags);
1800
1801 if (put_user(len, optlen) ||
1802 copy_to_user(optval, &val, len))
1803 return -EFAULT;
1804
1805 return 0;
1806}
1807
1808static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1809{
1810 struct nl_pktinfo info;
1811
1812 info.group = NETLINK_CB(skb).dst_group;
1813 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1814}
1815
1816static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1817 struct sk_buff *skb)
1818{
1819 if (!NETLINK_CB(skb).nsid_is_set)
1820 return;
1821
1822 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1823 &NETLINK_CB(skb).nsid);
1824}
1825
1826static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1827{
1828 struct sock *sk = sock->sk;
1829 struct netlink_sock *nlk = nlk_sk(sk);
1830 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1831 u32 dst_portid;
1832 u32 dst_group;
1833 struct sk_buff *skb;
1834 int err;
1835 struct scm_cookie scm;
1836 u32 netlink_skb_flags = 0;
1837
1838 if (msg->msg_flags & MSG_OOB)
1839 return -EOPNOTSUPP;
1840
1841 if (len == 0) {
1842 pr_warn_once("Zero length message leads to an empty skb\n");
1843 return -ENODATA;
1844 }
1845
1846 err = scm_send(sock, msg, &scm, true);
1847 if (err < 0)
1848 return err;
1849
1850 if (msg->msg_namelen) {
1851 err = -EINVAL;
1852 if (msg->msg_namelen < sizeof(struct sockaddr_nl))
1853 goto out;
1854 if (addr->nl_family != AF_NETLINK)
1855 goto out;
1856 dst_portid = addr->nl_pid;
1857 dst_group = ffs(addr->nl_groups);
1858 err = -EPERM;
1859 if ((dst_group || dst_portid) &&
1860 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1861 goto out;
1862 netlink_skb_flags |= NETLINK_SKB_DST;
1863 } else {
1864 /* Paired with WRITE_ONCE() in netlink_connect() */
1865 dst_portid = READ_ONCE(nlk->dst_portid);
1866 dst_group = READ_ONCE(nlk->dst_group);
1867 }
1868
1869 /* Paired with WRITE_ONCE() in netlink_insert() */
1870 if (!READ_ONCE(nlk->bound)) {
1871 err = netlink_autobind(sock);
1872 if (err)
1873 goto out;
1874 } else {
1875 /* Ensure nlk is hashed and visible. */
1876 smp_rmb();
1877 }
1878
1879 err = -EMSGSIZE;
1880 if (len > sk->sk_sndbuf - 32)
1881 goto out;
1882 err = -ENOBUFS;
1883 skb = netlink_alloc_large_skb(len, dst_group);
1884 if (skb == NULL)
1885 goto out;
1886
1887 NETLINK_CB(skb).portid = nlk->portid;
1888 NETLINK_CB(skb).dst_group = dst_group;
1889 NETLINK_CB(skb).creds = scm.creds;
1890 NETLINK_CB(skb).flags = netlink_skb_flags;
1891
1892 err = -EFAULT;
1893 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1894 kfree_skb(skb);
1895 goto out;
1896 }
1897
1898 err = security_netlink_send(sk, skb);
1899 if (err) {
1900 kfree_skb(skb);
1901 goto out;
1902 }
1903
1904 if (dst_group) {
1905 refcount_inc(&skb->users);
1906 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1907 }
1908 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags & MSG_DONTWAIT);
1909
1910out:
1911 scm_destroy(&scm);
1912 return err;
1913}
1914
1915static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1916 int flags)
1917{
1918 struct scm_cookie scm;
1919 struct sock *sk = sock->sk;
1920 struct netlink_sock *nlk = nlk_sk(sk);
1921 size_t copied, max_recvmsg_len;
1922 struct sk_buff *skb, *data_skb;
1923 int err, ret;
1924
1925 if (flags & MSG_OOB)
1926 return -EOPNOTSUPP;
1927
1928 copied = 0;
1929
1930 skb = skb_recv_datagram(sk, flags, &err);
1931 if (skb == NULL)
1932 goto out;
1933
1934 data_skb = skb;
1935
1936#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1937 if (unlikely(skb_shinfo(skb)->frag_list)) {
1938 /*
1939 * If this skb has a frag_list, then here that means that we
1940 * will have to use the frag_list skb's data for compat tasks
1941 * and the regular skb's data for normal (non-compat) tasks.
1942 *
1943 * If we need to send the compat skb, assign it to the
1944 * 'data_skb' variable so that it will be used below for data
1945 * copying. We keep 'skb' for everything else, including
1946 * freeing both later.
1947 */
1948 if (flags & MSG_CMSG_COMPAT)
1949 data_skb = skb_shinfo(skb)->frag_list;
1950 }
1951#endif
1952
1953 /* Record the max length of recvmsg() calls for future allocations */
1954 max_recvmsg_len = max(READ_ONCE(nlk->max_recvmsg_len), len);
1955 max_recvmsg_len = min_t(size_t, max_recvmsg_len,
1956 SKB_WITH_OVERHEAD(32768));
1957 WRITE_ONCE(nlk->max_recvmsg_len, max_recvmsg_len);
1958
1959 copied = data_skb->len;
1960 if (len < copied) {
1961 msg->msg_flags |= MSG_TRUNC;
1962 copied = len;
1963 }
1964
1965 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1966
1967 if (msg->msg_name) {
1968 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1969 addr->nl_family = AF_NETLINK;
1970 addr->nl_pad = 0;
1971 addr->nl_pid = NETLINK_CB(skb).portid;
1972 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1973 msg->msg_namelen = sizeof(*addr);
1974 }
1975
1976 if (nlk_test_bit(RECV_PKTINFO, sk))
1977 netlink_cmsg_recv_pktinfo(msg, skb);
1978 if (nlk_test_bit(LISTEN_ALL_NSID, sk))
1979 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1980
1981 memset(&scm, 0, sizeof(scm));
1982 scm.creds = *NETLINK_CREDS(skb);
1983 if (flags & MSG_TRUNC)
1984 copied = data_skb->len;
1985
1986 skb_free_datagram(sk, skb);
1987
1988 if (READ_ONCE(nlk->cb_running) &&
1989 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1990 ret = netlink_dump(sk);
1991 if (ret) {
1992 WRITE_ONCE(sk->sk_err, -ret);
1993 sk_error_report(sk);
1994 }
1995 }
1996
1997 scm_recv(sock, msg, &scm, flags);
1998out:
1999 netlink_rcv_wake(sk);
2000 return err ? : copied;
2001}
2002
2003static void netlink_data_ready(struct sock *sk)
2004{
2005 BUG();
2006}
2007
2008/*
2009 * We export these functions to other modules. They provide a
2010 * complete set of kernel non-blocking support for message
2011 * queueing.
2012 */
2013
2014struct sock *
2015__netlink_kernel_create(struct net *net, int unit, struct module *module,
2016 struct netlink_kernel_cfg *cfg)
2017{
2018 struct socket *sock;
2019 struct sock *sk;
2020 struct netlink_sock *nlk;
2021 struct listeners *listeners = NULL;
2022 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2023 unsigned int groups;
2024
2025 BUG_ON(!nl_table);
2026
2027 if (unit < 0 || unit >= MAX_LINKS)
2028 return NULL;
2029
2030 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2031 return NULL;
2032
2033 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
2034 goto out_sock_release_nosk;
2035
2036 sk = sock->sk;
2037
2038 if (!cfg || cfg->groups < 32)
2039 groups = 32;
2040 else
2041 groups = cfg->groups;
2042
2043 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2044 if (!listeners)
2045 goto out_sock_release;
2046
2047 sk->sk_data_ready = netlink_data_ready;
2048 if (cfg && cfg->input)
2049 nlk_sk(sk)->netlink_rcv = cfg->input;
2050
2051 if (netlink_insert(sk, 0))
2052 goto out_sock_release;
2053
2054 nlk = nlk_sk(sk);
2055 set_bit(NETLINK_F_KERNEL_SOCKET, &nlk->flags);
2056
2057 netlink_table_grab();
2058 if (!nl_table[unit].registered) {
2059 nl_table[unit].groups = groups;
2060 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2061 nl_table[unit].cb_mutex = cb_mutex;
2062 nl_table[unit].module = module;
2063 if (cfg) {
2064 nl_table[unit].bind = cfg->bind;
2065 nl_table[unit].unbind = cfg->unbind;
2066 nl_table[unit].release = cfg->release;
2067 nl_table[unit].flags = cfg->flags;
2068 }
2069 nl_table[unit].registered = 1;
2070 } else {
2071 kfree(listeners);
2072 nl_table[unit].registered++;
2073 }
2074 netlink_table_ungrab();
2075 return sk;
2076
2077out_sock_release:
2078 kfree(listeners);
2079 netlink_kernel_release(sk);
2080 return NULL;
2081
2082out_sock_release_nosk:
2083 sock_release(sock);
2084 return NULL;
2085}
2086EXPORT_SYMBOL(__netlink_kernel_create);
2087
2088void
2089netlink_kernel_release(struct sock *sk)
2090{
2091 if (sk == NULL || sk->sk_socket == NULL)
2092 return;
2093
2094 sock_release(sk->sk_socket);
2095}
2096EXPORT_SYMBOL(netlink_kernel_release);
2097
2098int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2099{
2100 struct listeners *new, *old;
2101 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2102
2103 if (groups < 32)
2104 groups = 32;
2105
2106 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2107 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2108 if (!new)
2109 return -ENOMEM;
2110 old = nl_deref_protected(tbl->listeners);
2111 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2112 rcu_assign_pointer(tbl->listeners, new);
2113
2114 kfree_rcu(old, rcu);
2115 }
2116 tbl->groups = groups;
2117
2118 return 0;
2119}
2120
2121/**
2122 * netlink_change_ngroups - change number of multicast groups
2123 *
2124 * This changes the number of multicast groups that are available
2125 * on a certain netlink family. Note that it is not possible to
2126 * change the number of groups to below 32. Also note that it does
2127 * not implicitly call netlink_clear_multicast_users() when the
2128 * number of groups is reduced.
2129 *
2130 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2131 * @groups: The new number of groups.
2132 */
2133int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2134{
2135 int err;
2136
2137 netlink_table_grab();
2138 err = __netlink_change_ngroups(sk, groups);
2139 netlink_table_ungrab();
2140
2141 return err;
2142}
2143
2144void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2145{
2146 struct sock *sk;
2147 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2148
2149 sk_for_each_bound(sk, &tbl->mc_list)
2150 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2151}
2152
2153struct nlmsghdr *
2154__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2155{
2156 struct nlmsghdr *nlh;
2157 int size = nlmsg_msg_size(len);
2158
2159 nlh = skb_put(skb, NLMSG_ALIGN(size));
2160 nlh->nlmsg_type = type;
2161 nlh->nlmsg_len = size;
2162 nlh->nlmsg_flags = flags;
2163 nlh->nlmsg_pid = portid;
2164 nlh->nlmsg_seq = seq;
2165 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2166 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2167 return nlh;
2168}
2169EXPORT_SYMBOL(__nlmsg_put);
2170
2171/*
2172 * It looks a bit ugly.
2173 * It would be better to create kernel thread.
2174 */
2175
2176static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb,
2177 struct netlink_callback *cb,
2178 struct netlink_ext_ack *extack)
2179{
2180 struct nlmsghdr *nlh;
2181
2182 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(nlk->dump_done_errno),
2183 NLM_F_MULTI | cb->answer_flags);
2184 if (WARN_ON(!nlh))
2185 return -ENOBUFS;
2186
2187 nl_dump_check_consistent(cb, nlh);
2188 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, sizeof(nlk->dump_done_errno));
2189
2190 if (extack->_msg && test_bit(NETLINK_F_EXT_ACK, &nlk->flags)) {
2191 nlh->nlmsg_flags |= NLM_F_ACK_TLVS;
2192 if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg))
2193 nlmsg_end(skb, nlh);
2194 }
2195
2196 return 0;
2197}
2198
2199static int netlink_dump(struct sock *sk)
2200{
2201 struct netlink_sock *nlk = nlk_sk(sk);
2202 struct netlink_ext_ack extack = {};
2203 struct netlink_callback *cb;
2204 struct sk_buff *skb = NULL;
2205 size_t max_recvmsg_len;
2206 struct module *module;
2207 int err = -ENOBUFS;
2208 int alloc_min_size;
2209 int alloc_size;
2210
2211 mutex_lock(nlk->cb_mutex);
2212 if (!nlk->cb_running) {
2213 err = -EINVAL;
2214 goto errout_skb;
2215 }
2216
2217 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2218 goto errout_skb;
2219
2220 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2221 * required, but it makes sense to _attempt_ a 16K bytes allocation
2222 * to reduce number of system calls on dump operations, if user
2223 * ever provided a big enough buffer.
2224 */
2225 cb = &nlk->cb;
2226 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2227
2228 max_recvmsg_len = READ_ONCE(nlk->max_recvmsg_len);
2229 if (alloc_min_size < max_recvmsg_len) {
2230 alloc_size = max_recvmsg_len;
2231 skb = alloc_skb(alloc_size,
2232 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2233 __GFP_NOWARN | __GFP_NORETRY);
2234 }
2235 if (!skb) {
2236 alloc_size = alloc_min_size;
2237 skb = alloc_skb(alloc_size, GFP_KERNEL);
2238 }
2239 if (!skb)
2240 goto errout_skb;
2241
2242 /* Trim skb to allocated size. User is expected to provide buffer as
2243 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2244 * netlink_recvmsg())). dump will pack as many smaller messages as
2245 * could fit within the allocated skb. skb is typically allocated
2246 * with larger space than required (could be as much as near 2x the
2247 * requested size with align to next power of 2 approach). Allowing
2248 * dump to use the excess space makes it difficult for a user to have a
2249 * reasonable static buffer based on the expected largest dump of a
2250 * single netdev. The outcome is MSG_TRUNC error.
2251 */
2252 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2253
2254 /* Make sure malicious BPF programs can not read unitialized memory
2255 * from skb->head -> skb->data
2256 */
2257 skb_reset_network_header(skb);
2258 skb_reset_mac_header(skb);
2259
2260 netlink_skb_set_owner_r(skb, sk);
2261
2262 if (nlk->dump_done_errno > 0) {
2263 cb->extack = &extack;
2264 nlk->dump_done_errno = cb->dump(skb, cb);
2265 cb->extack = NULL;
2266 }
2267
2268 if (nlk->dump_done_errno > 0 ||
2269 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
2270 mutex_unlock(nlk->cb_mutex);
2271
2272 if (sk_filter(sk, skb))
2273 kfree_skb(skb);
2274 else
2275 __netlink_sendskb(sk, skb);
2276 return 0;
2277 }
2278
2279 if (netlink_dump_done(nlk, skb, cb, &extack))
2280 goto errout_skb;
2281
2282#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2283 /* frag_list skb's data is used for compat tasks
2284 * and the regular skb's data for normal (non-compat) tasks.
2285 * See netlink_recvmsg().
2286 */
2287 if (unlikely(skb_shinfo(skb)->frag_list)) {
2288 if (netlink_dump_done(nlk, skb_shinfo(skb)->frag_list, cb, &extack))
2289 goto errout_skb;
2290 }
2291#endif
2292
2293 if (sk_filter(sk, skb))
2294 kfree_skb(skb);
2295 else
2296 __netlink_sendskb(sk, skb);
2297
2298 if (cb->done)
2299 cb->done(cb);
2300
2301 WRITE_ONCE(nlk->cb_running, false);
2302 module = cb->module;
2303 skb = cb->skb;
2304 mutex_unlock(nlk->cb_mutex);
2305 module_put(module);
2306 consume_skb(skb);
2307 return 0;
2308
2309errout_skb:
2310 mutex_unlock(nlk->cb_mutex);
2311 kfree_skb(skb);
2312 return err;
2313}
2314
2315int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2316 const struct nlmsghdr *nlh,
2317 struct netlink_dump_control *control)
2318{
2319 struct netlink_callback *cb;
2320 struct netlink_sock *nlk;
2321 struct sock *sk;
2322 int ret;
2323
2324 refcount_inc(&skb->users);
2325
2326 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2327 if (sk == NULL) {
2328 ret = -ECONNREFUSED;
2329 goto error_free;
2330 }
2331
2332 nlk = nlk_sk(sk);
2333 mutex_lock(nlk->cb_mutex);
2334 /* A dump is in progress... */
2335 if (nlk->cb_running) {
2336 ret = -EBUSY;
2337 goto error_unlock;
2338 }
2339 /* add reference of module which cb->dump belongs to */
2340 if (!try_module_get(control->module)) {
2341 ret = -EPROTONOSUPPORT;
2342 goto error_unlock;
2343 }
2344
2345 cb = &nlk->cb;
2346 memset(cb, 0, sizeof(*cb));
2347 cb->dump = control->dump;
2348 cb->done = control->done;
2349 cb->nlh = nlh;
2350 cb->data = control->data;
2351 cb->module = control->module;
2352 cb->min_dump_alloc = control->min_dump_alloc;
2353 cb->skb = skb;
2354
2355 cb->strict_check = nlk_test_bit(STRICT_CHK, NETLINK_CB(skb).sk);
2356
2357 if (control->start) {
2358 cb->extack = control->extack;
2359 ret = control->start(cb);
2360 cb->extack = NULL;
2361 if (ret)
2362 goto error_put;
2363 }
2364
2365 WRITE_ONCE(nlk->cb_running, true);
2366 nlk->dump_done_errno = INT_MAX;
2367
2368 mutex_unlock(nlk->cb_mutex);
2369
2370 ret = netlink_dump(sk);
2371
2372 sock_put(sk);
2373
2374 if (ret)
2375 return ret;
2376
2377 /* We successfully started a dump, by returning -EINTR we
2378 * signal not to send ACK even if it was requested.
2379 */
2380 return -EINTR;
2381
2382error_put:
2383 module_put(control->module);
2384error_unlock:
2385 sock_put(sk);
2386 mutex_unlock(nlk->cb_mutex);
2387error_free:
2388 kfree_skb(skb);
2389 return ret;
2390}
2391EXPORT_SYMBOL(__netlink_dump_start);
2392
2393static size_t
2394netlink_ack_tlv_len(struct netlink_sock *nlk, int err,
2395 const struct netlink_ext_ack *extack)
2396{
2397 size_t tlvlen;
2398
2399 if (!extack || !test_bit(NETLINK_F_EXT_ACK, &nlk->flags))
2400 return 0;
2401
2402 tlvlen = 0;
2403 if (extack->_msg)
2404 tlvlen += nla_total_size(strlen(extack->_msg) + 1);
2405 if (extack->cookie_len)
2406 tlvlen += nla_total_size(extack->cookie_len);
2407
2408 /* Following attributes are only reported as error (not warning) */
2409 if (!err)
2410 return tlvlen;
2411
2412 if (extack->bad_attr)
2413 tlvlen += nla_total_size(sizeof(u32));
2414 if (extack->policy)
2415 tlvlen += netlink_policy_dump_attr_size_estimate(extack->policy);
2416 if (extack->miss_type)
2417 tlvlen += nla_total_size(sizeof(u32));
2418 if (extack->miss_nest)
2419 tlvlen += nla_total_size(sizeof(u32));
2420
2421 return tlvlen;
2422}
2423
2424static void
2425netlink_ack_tlv_fill(struct sk_buff *in_skb, struct sk_buff *skb,
2426 struct nlmsghdr *nlh, int err,
2427 const struct netlink_ext_ack *extack)
2428{
2429 if (extack->_msg)
2430 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg));
2431 if (extack->cookie_len)
2432 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
2433 extack->cookie_len, extack->cookie));
2434
2435 if (!err)
2436 return;
2437
2438 if (extack->bad_attr &&
2439 !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
2440 (u8 *)extack->bad_attr >= in_skb->data + in_skb->len))
2441 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
2442 (u8 *)extack->bad_attr - (u8 *)nlh));
2443 if (extack->policy)
2444 netlink_policy_dump_write_attr(skb, extack->policy,
2445 NLMSGERR_ATTR_POLICY);
2446 if (extack->miss_type)
2447 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_TYPE,
2448 extack->miss_type));
2449 if (extack->miss_nest &&
2450 !WARN_ON((u8 *)extack->miss_nest < in_skb->data ||
2451 (u8 *)extack->miss_nest > in_skb->data + in_skb->len))
2452 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_NEST,
2453 (u8 *)extack->miss_nest - (u8 *)nlh));
2454}
2455
2456void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
2457 const struct netlink_ext_ack *extack)
2458{
2459 struct sk_buff *skb;
2460 struct nlmsghdr *rep;
2461 struct nlmsgerr *errmsg;
2462 size_t payload = sizeof(*errmsg);
2463 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2464 unsigned int flags = 0;
2465 size_t tlvlen;
2466
2467 /* Error messages get the original request appened, unless the user
2468 * requests to cap the error message, and get extra error data if
2469 * requested.
2470 */
2471 if (err && !test_bit(NETLINK_F_CAP_ACK, &nlk->flags))
2472 payload += nlmsg_len(nlh);
2473 else
2474 flags |= NLM_F_CAPPED;
2475
2476 tlvlen = netlink_ack_tlv_len(nlk, err, extack);
2477 if (tlvlen)
2478 flags |= NLM_F_ACK_TLVS;
2479
2480 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
2481 if (!skb)
2482 goto err_skb;
2483
2484 rep = nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2485 NLMSG_ERROR, sizeof(*errmsg), flags);
2486 if (!rep)
2487 goto err_bad_put;
2488 errmsg = nlmsg_data(rep);
2489 errmsg->error = err;
2490 errmsg->msg = *nlh;
2491
2492 if (!(flags & NLM_F_CAPPED)) {
2493 if (!nlmsg_append(skb, nlmsg_len(nlh)))
2494 goto err_bad_put;
2495
2496 memcpy(nlmsg_data(&errmsg->msg), nlmsg_data(nlh),
2497 nlmsg_len(nlh));
2498 }
2499
2500 if (tlvlen)
2501 netlink_ack_tlv_fill(in_skb, skb, nlh, err, extack);
2502
2503 nlmsg_end(skb, rep);
2504
2505 nlmsg_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid);
2506
2507 return;
2508
2509err_bad_put:
2510 nlmsg_free(skb);
2511err_skb:
2512 WRITE_ONCE(NETLINK_CB(in_skb).sk->sk_err, ENOBUFS);
2513 sk_error_report(NETLINK_CB(in_skb).sk);
2514}
2515EXPORT_SYMBOL(netlink_ack);
2516
2517int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2518 struct nlmsghdr *,
2519 struct netlink_ext_ack *))
2520{
2521 struct netlink_ext_ack extack;
2522 struct nlmsghdr *nlh;
2523 int err;
2524
2525 while (skb->len >= nlmsg_total_size(0)) {
2526 int msglen;
2527
2528 memset(&extack, 0, sizeof(extack));
2529 nlh = nlmsg_hdr(skb);
2530 err = 0;
2531
2532 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2533 return 0;
2534
2535 /* Only requests are handled by the kernel */
2536 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2537 goto ack;
2538
2539 /* Skip control messages */
2540 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2541 goto ack;
2542
2543 err = cb(skb, nlh, &extack);
2544 if (err == -EINTR)
2545 goto skip;
2546
2547ack:
2548 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2549 netlink_ack(skb, nlh, err, &extack);
2550
2551skip:
2552 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2553 if (msglen > skb->len)
2554 msglen = skb->len;
2555 skb_pull(skb, msglen);
2556 }
2557
2558 return 0;
2559}
2560EXPORT_SYMBOL(netlink_rcv_skb);
2561
2562/**
2563 * nlmsg_notify - send a notification netlink message
2564 * @sk: netlink socket to use
2565 * @skb: notification message
2566 * @portid: destination netlink portid for reports or 0
2567 * @group: destination multicast group or 0
2568 * @report: 1 to report back, 0 to disable
2569 * @flags: allocation flags
2570 */
2571int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2572 unsigned int group, int report, gfp_t flags)
2573{
2574 int err = 0;
2575
2576 if (group) {
2577 int exclude_portid = 0;
2578
2579 if (report) {
2580 refcount_inc(&skb->users);
2581 exclude_portid = portid;
2582 }
2583
2584 /* errors reported via destination sk->sk_err, but propagate
2585 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2586 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2587 if (err == -ESRCH)
2588 err = 0;
2589 }
2590
2591 if (report) {
2592 int err2;
2593
2594 err2 = nlmsg_unicast(sk, skb, portid);
2595 if (!err)
2596 err = err2;
2597 }
2598
2599 return err;
2600}
2601EXPORT_SYMBOL(nlmsg_notify);
2602
2603#ifdef CONFIG_PROC_FS
2604struct nl_seq_iter {
2605 struct seq_net_private p;
2606 struct rhashtable_iter hti;
2607 int link;
2608};
2609
2610static void netlink_walk_start(struct nl_seq_iter *iter)
2611{
2612 rhashtable_walk_enter(&nl_table[iter->link].hash, &iter->hti);
2613 rhashtable_walk_start(&iter->hti);
2614}
2615
2616static void netlink_walk_stop(struct nl_seq_iter *iter)
2617{
2618 rhashtable_walk_stop(&iter->hti);
2619 rhashtable_walk_exit(&iter->hti);
2620}
2621
2622static void *__netlink_seq_next(struct seq_file *seq)
2623{
2624 struct nl_seq_iter *iter = seq->private;
2625 struct netlink_sock *nlk;
2626
2627 do {
2628 for (;;) {
2629 nlk = rhashtable_walk_next(&iter->hti);
2630
2631 if (IS_ERR(nlk)) {
2632 if (PTR_ERR(nlk) == -EAGAIN)
2633 continue;
2634
2635 return nlk;
2636 }
2637
2638 if (nlk)
2639 break;
2640
2641 netlink_walk_stop(iter);
2642 if (++iter->link >= MAX_LINKS)
2643 return NULL;
2644
2645 netlink_walk_start(iter);
2646 }
2647 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2648
2649 return nlk;
2650}
2651
2652static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2653 __acquires(RCU)
2654{
2655 struct nl_seq_iter *iter = seq->private;
2656 void *obj = SEQ_START_TOKEN;
2657 loff_t pos;
2658
2659 iter->link = 0;
2660
2661 netlink_walk_start(iter);
2662
2663 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2664 obj = __netlink_seq_next(seq);
2665
2666 return obj;
2667}
2668
2669static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2670{
2671 ++*pos;
2672 return __netlink_seq_next(seq);
2673}
2674
2675static void netlink_native_seq_stop(struct seq_file *seq, void *v)
2676{
2677 struct nl_seq_iter *iter = seq->private;
2678
2679 if (iter->link >= MAX_LINKS)
2680 return;
2681
2682 netlink_walk_stop(iter);
2683}
2684
2685
2686static int netlink_native_seq_show(struct seq_file *seq, void *v)
2687{
2688 if (v == SEQ_START_TOKEN) {
2689 seq_puts(seq,
2690 "sk Eth Pid Groups "
2691 "Rmem Wmem Dump Locks Drops Inode\n");
2692 } else {
2693 struct sock *s = v;
2694 struct netlink_sock *nlk = nlk_sk(s);
2695
2696 seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8u %-8lu\n",
2697 s,
2698 s->sk_protocol,
2699 nlk->portid,
2700 nlk->groups ? (u32)nlk->groups[0] : 0,
2701 sk_rmem_alloc_get(s),
2702 sk_wmem_alloc_get(s),
2703 READ_ONCE(nlk->cb_running),
2704 refcount_read(&s->sk_refcnt),
2705 atomic_read(&s->sk_drops),
2706 sock_i_ino(s)
2707 );
2708
2709 }
2710 return 0;
2711}
2712
2713#ifdef CONFIG_BPF_SYSCALL
2714struct bpf_iter__netlink {
2715 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2716 __bpf_md_ptr(struct netlink_sock *, sk);
2717};
2718
2719DEFINE_BPF_ITER_FUNC(netlink, struct bpf_iter_meta *meta, struct netlink_sock *sk)
2720
2721static int netlink_prog_seq_show(struct bpf_prog *prog,
2722 struct bpf_iter_meta *meta,
2723 void *v)
2724{
2725 struct bpf_iter__netlink ctx;
2726
2727 meta->seq_num--; /* skip SEQ_START_TOKEN */
2728 ctx.meta = meta;
2729 ctx.sk = nlk_sk((struct sock *)v);
2730 return bpf_iter_run_prog(prog, &ctx);
2731}
2732
2733static int netlink_seq_show(struct seq_file *seq, void *v)
2734{
2735 struct bpf_iter_meta meta;
2736 struct bpf_prog *prog;
2737
2738 meta.seq = seq;
2739 prog = bpf_iter_get_info(&meta, false);
2740 if (!prog)
2741 return netlink_native_seq_show(seq, v);
2742
2743 if (v != SEQ_START_TOKEN)
2744 return netlink_prog_seq_show(prog, &meta, v);
2745
2746 return 0;
2747}
2748
2749static void netlink_seq_stop(struct seq_file *seq, void *v)
2750{
2751 struct bpf_iter_meta meta;
2752 struct bpf_prog *prog;
2753
2754 if (!v) {
2755 meta.seq = seq;
2756 prog = bpf_iter_get_info(&meta, true);
2757 if (prog)
2758 (void)netlink_prog_seq_show(prog, &meta, v);
2759 }
2760
2761 netlink_native_seq_stop(seq, v);
2762}
2763#else
2764static int netlink_seq_show(struct seq_file *seq, void *v)
2765{
2766 return netlink_native_seq_show(seq, v);
2767}
2768
2769static void netlink_seq_stop(struct seq_file *seq, void *v)
2770{
2771 netlink_native_seq_stop(seq, v);
2772}
2773#endif
2774
2775static const struct seq_operations netlink_seq_ops = {
2776 .start = netlink_seq_start,
2777 .next = netlink_seq_next,
2778 .stop = netlink_seq_stop,
2779 .show = netlink_seq_show,
2780};
2781#endif
2782
2783int netlink_register_notifier(struct notifier_block *nb)
2784{
2785 return blocking_notifier_chain_register(&netlink_chain, nb);
2786}
2787EXPORT_SYMBOL(netlink_register_notifier);
2788
2789int netlink_unregister_notifier(struct notifier_block *nb)
2790{
2791 return blocking_notifier_chain_unregister(&netlink_chain, nb);
2792}
2793EXPORT_SYMBOL(netlink_unregister_notifier);
2794
2795static const struct proto_ops netlink_ops = {
2796 .family = PF_NETLINK,
2797 .owner = THIS_MODULE,
2798 .release = netlink_release,
2799 .bind = netlink_bind,
2800 .connect = netlink_connect,
2801 .socketpair = sock_no_socketpair,
2802 .accept = sock_no_accept,
2803 .getname = netlink_getname,
2804 .poll = datagram_poll,
2805 .ioctl = netlink_ioctl,
2806 .listen = sock_no_listen,
2807 .shutdown = sock_no_shutdown,
2808 .setsockopt = netlink_setsockopt,
2809 .getsockopt = netlink_getsockopt,
2810 .sendmsg = netlink_sendmsg,
2811 .recvmsg = netlink_recvmsg,
2812 .mmap = sock_no_mmap,
2813};
2814
2815static const struct net_proto_family netlink_family_ops = {
2816 .family = PF_NETLINK,
2817 .create = netlink_create,
2818 .owner = THIS_MODULE, /* for consistency 8) */
2819};
2820
2821static int __net_init netlink_net_init(struct net *net)
2822{
2823#ifdef CONFIG_PROC_FS
2824 if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops,
2825 sizeof(struct nl_seq_iter)))
2826 return -ENOMEM;
2827#endif
2828 return 0;
2829}
2830
2831static void __net_exit netlink_net_exit(struct net *net)
2832{
2833#ifdef CONFIG_PROC_FS
2834 remove_proc_entry("netlink", net->proc_net);
2835#endif
2836}
2837
2838static void __init netlink_add_usersock_entry(void)
2839{
2840 struct listeners *listeners;
2841 int groups = 32;
2842
2843 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2844 if (!listeners)
2845 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2846
2847 netlink_table_grab();
2848
2849 nl_table[NETLINK_USERSOCK].groups = groups;
2850 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2851 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2852 nl_table[NETLINK_USERSOCK].registered = 1;
2853 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2854
2855 netlink_table_ungrab();
2856}
2857
2858static struct pernet_operations __net_initdata netlink_net_ops = {
2859 .init = netlink_net_init,
2860 .exit = netlink_net_exit,
2861};
2862
2863static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2864{
2865 const struct netlink_sock *nlk = data;
2866 struct netlink_compare_arg arg;
2867
2868 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2869 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2870}
2871
2872static const struct rhashtable_params netlink_rhashtable_params = {
2873 .head_offset = offsetof(struct netlink_sock, node),
2874 .key_len = netlink_compare_arg_len,
2875 .obj_hashfn = netlink_hash,
2876 .obj_cmpfn = netlink_compare,
2877 .automatic_shrinking = true,
2878};
2879
2880#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2881BTF_ID_LIST(btf_netlink_sock_id)
2882BTF_ID(struct, netlink_sock)
2883
2884static const struct bpf_iter_seq_info netlink_seq_info = {
2885 .seq_ops = &netlink_seq_ops,
2886 .init_seq_private = bpf_iter_init_seq_net,
2887 .fini_seq_private = bpf_iter_fini_seq_net,
2888 .seq_priv_size = sizeof(struct nl_seq_iter),
2889};
2890
2891static struct bpf_iter_reg netlink_reg_info = {
2892 .target = "netlink",
2893 .ctx_arg_info_size = 1,
2894 .ctx_arg_info = {
2895 { offsetof(struct bpf_iter__netlink, sk),
2896 PTR_TO_BTF_ID_OR_NULL },
2897 },
2898 .seq_info = &netlink_seq_info,
2899};
2900
2901static int __init bpf_iter_register(void)
2902{
2903 netlink_reg_info.ctx_arg_info[0].btf_id = *btf_netlink_sock_id;
2904 return bpf_iter_reg_target(&netlink_reg_info);
2905}
2906#endif
2907
2908static int __init netlink_proto_init(void)
2909{
2910 int i;
2911 int err = proto_register(&netlink_proto, 0);
2912
2913 if (err != 0)
2914 goto out;
2915
2916#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2917 err = bpf_iter_register();
2918 if (err)
2919 goto out;
2920#endif
2921
2922 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof_field(struct sk_buff, cb));
2923
2924 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2925 if (!nl_table)
2926 goto panic;
2927
2928 for (i = 0; i < MAX_LINKS; i++) {
2929 if (rhashtable_init(&nl_table[i].hash,
2930 &netlink_rhashtable_params) < 0) {
2931 while (--i > 0)
2932 rhashtable_destroy(&nl_table[i].hash);
2933 kfree(nl_table);
2934 goto panic;
2935 }
2936 }
2937
2938 netlink_add_usersock_entry();
2939
2940 sock_register(&netlink_family_ops);
2941 register_pernet_subsys(&netlink_net_ops);
2942 register_pernet_subsys(&netlink_tap_net_ops);
2943 /* The netlink device handler may be needed early. */
2944 rtnetlink_init();
2945out:
2946 return err;
2947panic:
2948 panic("netlink_init: Cannot allocate nl_table\n");
2949}
2950
2951core_initcall(netlink_proto_init);
1/*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 * Patrick McHardy <kaber@trash.net>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 *
13 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
14 * added netlink_proto_exit
15 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
16 * use nlk_sk, as sk->protinfo is on a diet 8)
17 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
18 * - inc module use count of module that owns
19 * the kernel socket in case userspace opens
20 * socket of same protocol
21 * - remove all module support, since netlink is
22 * mandatory if CONFIG_NET=y these days
23 */
24
25#include <linux/module.h>
26
27#include <linux/capability.h>
28#include <linux/kernel.h>
29#include <linux/init.h>
30#include <linux/signal.h>
31#include <linux/sched.h>
32#include <linux/errno.h>
33#include <linux/string.h>
34#include <linux/stat.h>
35#include <linux/socket.h>
36#include <linux/un.h>
37#include <linux/fcntl.h>
38#include <linux/termios.h>
39#include <linux/sockios.h>
40#include <linux/net.h>
41#include <linux/fs.h>
42#include <linux/slab.h>
43#include <asm/uaccess.h>
44#include <linux/skbuff.h>
45#include <linux/netdevice.h>
46#include <linux/rtnetlink.h>
47#include <linux/proc_fs.h>
48#include <linux/seq_file.h>
49#include <linux/notifier.h>
50#include <linux/security.h>
51#include <linux/jhash.h>
52#include <linux/jiffies.h>
53#include <linux/random.h>
54#include <linux/bitops.h>
55#include <linux/mm.h>
56#include <linux/types.h>
57#include <linux/audit.h>
58#include <linux/mutex.h>
59#include <linux/vmalloc.h>
60#include <linux/if_arp.h>
61#include <asm/cacheflush.h>
62
63#include <net/net_namespace.h>
64#include <net/sock.h>
65#include <net/scm.h>
66#include <net/netlink.h>
67
68#include "af_netlink.h"
69
70struct listeners {
71 struct rcu_head rcu;
72 unsigned long masks[0];
73};
74
75/* state bits */
76#define NETLINK_CONGESTED 0x0
77
78/* flags */
79#define NETLINK_KERNEL_SOCKET 0x1
80#define NETLINK_RECV_PKTINFO 0x2
81#define NETLINK_BROADCAST_SEND_ERROR 0x4
82#define NETLINK_RECV_NO_ENOBUFS 0x8
83
84static inline int netlink_is_kernel(struct sock *sk)
85{
86 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
87}
88
89struct netlink_table *nl_table;
90EXPORT_SYMBOL_GPL(nl_table);
91
92static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
93
94static int netlink_dump(struct sock *sk);
95static void netlink_skb_destructor(struct sk_buff *skb);
96
97DEFINE_RWLOCK(nl_table_lock);
98EXPORT_SYMBOL_GPL(nl_table_lock);
99static atomic_t nl_table_users = ATOMIC_INIT(0);
100
101#define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
102
103static ATOMIC_NOTIFIER_HEAD(netlink_chain);
104
105static DEFINE_SPINLOCK(netlink_tap_lock);
106static struct list_head netlink_tap_all __read_mostly;
107
108static inline u32 netlink_group_mask(u32 group)
109{
110 return group ? 1 << (group - 1) : 0;
111}
112
113static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u32 portid)
114{
115 return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask];
116}
117
118int netlink_add_tap(struct netlink_tap *nt)
119{
120 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
121 return -EINVAL;
122
123 spin_lock(&netlink_tap_lock);
124 list_add_rcu(&nt->list, &netlink_tap_all);
125 spin_unlock(&netlink_tap_lock);
126
127 if (nt->module)
128 __module_get(nt->module);
129
130 return 0;
131}
132EXPORT_SYMBOL_GPL(netlink_add_tap);
133
134static int __netlink_remove_tap(struct netlink_tap *nt)
135{
136 bool found = false;
137 struct netlink_tap *tmp;
138
139 spin_lock(&netlink_tap_lock);
140
141 list_for_each_entry(tmp, &netlink_tap_all, list) {
142 if (nt == tmp) {
143 list_del_rcu(&nt->list);
144 found = true;
145 goto out;
146 }
147 }
148
149 pr_warn("__netlink_remove_tap: %p not found\n", nt);
150out:
151 spin_unlock(&netlink_tap_lock);
152
153 if (found && nt->module)
154 module_put(nt->module);
155
156 return found ? 0 : -ENODEV;
157}
158
159int netlink_remove_tap(struct netlink_tap *nt)
160{
161 int ret;
162
163 ret = __netlink_remove_tap(nt);
164 synchronize_net();
165
166 return ret;
167}
168EXPORT_SYMBOL_GPL(netlink_remove_tap);
169
170static bool netlink_filter_tap(const struct sk_buff *skb)
171{
172 struct sock *sk = skb->sk;
173 bool pass = false;
174
175 /* We take the more conservative approach and
176 * whitelist socket protocols that may pass.
177 */
178 switch (sk->sk_protocol) {
179 case NETLINK_ROUTE:
180 case NETLINK_USERSOCK:
181 case NETLINK_SOCK_DIAG:
182 case NETLINK_NFLOG:
183 case NETLINK_XFRM:
184 case NETLINK_FIB_LOOKUP:
185 case NETLINK_NETFILTER:
186 case NETLINK_GENERIC:
187 pass = true;
188 break;
189 }
190
191 return pass;
192}
193
194static int __netlink_deliver_tap_skb(struct sk_buff *skb,
195 struct net_device *dev)
196{
197 struct sk_buff *nskb;
198 struct sock *sk = skb->sk;
199 int ret = -ENOMEM;
200
201 dev_hold(dev);
202 nskb = skb_clone(skb, GFP_ATOMIC);
203 if (nskb) {
204 nskb->dev = dev;
205 nskb->protocol = htons((u16) sk->sk_protocol);
206 nskb->pkt_type = netlink_is_kernel(sk) ?
207 PACKET_KERNEL : PACKET_USER;
208
209 ret = dev_queue_xmit(nskb);
210 if (unlikely(ret > 0))
211 ret = net_xmit_errno(ret);
212 }
213
214 dev_put(dev);
215 return ret;
216}
217
218static void __netlink_deliver_tap(struct sk_buff *skb)
219{
220 int ret;
221 struct netlink_tap *tmp;
222
223 if (!netlink_filter_tap(skb))
224 return;
225
226 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
227 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
228 if (unlikely(ret))
229 break;
230 }
231}
232
233static void netlink_deliver_tap(struct sk_buff *skb)
234{
235 rcu_read_lock();
236
237 if (unlikely(!list_empty(&netlink_tap_all)))
238 __netlink_deliver_tap(skb);
239
240 rcu_read_unlock();
241}
242
243static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
244 struct sk_buff *skb)
245{
246 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
247 netlink_deliver_tap(skb);
248}
249
250static void netlink_overrun(struct sock *sk)
251{
252 struct netlink_sock *nlk = nlk_sk(sk);
253
254 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
255 if (!test_and_set_bit(NETLINK_CONGESTED, &nlk_sk(sk)->state)) {
256 sk->sk_err = ENOBUFS;
257 sk->sk_error_report(sk);
258 }
259 }
260 atomic_inc(&sk->sk_drops);
261}
262
263static void netlink_rcv_wake(struct sock *sk)
264{
265 struct netlink_sock *nlk = nlk_sk(sk);
266
267 if (skb_queue_empty(&sk->sk_receive_queue))
268 clear_bit(NETLINK_CONGESTED, &nlk->state);
269 if (!test_bit(NETLINK_CONGESTED, &nlk->state))
270 wake_up_interruptible(&nlk->wait);
271}
272
273#ifdef CONFIG_NETLINK_MMAP
274static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
275{
276 return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
277}
278
279static bool netlink_rx_is_mmaped(struct sock *sk)
280{
281 return nlk_sk(sk)->rx_ring.pg_vec != NULL;
282}
283
284static bool netlink_tx_is_mmaped(struct sock *sk)
285{
286 return nlk_sk(sk)->tx_ring.pg_vec != NULL;
287}
288
289static __pure struct page *pgvec_to_page(const void *addr)
290{
291 if (is_vmalloc_addr(addr))
292 return vmalloc_to_page(addr);
293 else
294 return virt_to_page(addr);
295}
296
297static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len)
298{
299 unsigned int i;
300
301 for (i = 0; i < len; i++) {
302 if (pg_vec[i] != NULL) {
303 if (is_vmalloc_addr(pg_vec[i]))
304 vfree(pg_vec[i]);
305 else
306 free_pages((unsigned long)pg_vec[i], order);
307 }
308 }
309 kfree(pg_vec);
310}
311
312static void *alloc_one_pg_vec_page(unsigned long order)
313{
314 void *buffer;
315 gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO |
316 __GFP_NOWARN | __GFP_NORETRY;
317
318 buffer = (void *)__get_free_pages(gfp_flags, order);
319 if (buffer != NULL)
320 return buffer;
321
322 buffer = vzalloc((1 << order) * PAGE_SIZE);
323 if (buffer != NULL)
324 return buffer;
325
326 gfp_flags &= ~__GFP_NORETRY;
327 return (void *)__get_free_pages(gfp_flags, order);
328}
329
330static void **alloc_pg_vec(struct netlink_sock *nlk,
331 struct nl_mmap_req *req, unsigned int order)
332{
333 unsigned int block_nr = req->nm_block_nr;
334 unsigned int i;
335 void **pg_vec;
336
337 pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL);
338 if (pg_vec == NULL)
339 return NULL;
340
341 for (i = 0; i < block_nr; i++) {
342 pg_vec[i] = alloc_one_pg_vec_page(order);
343 if (pg_vec[i] == NULL)
344 goto err1;
345 }
346
347 return pg_vec;
348err1:
349 free_pg_vec(pg_vec, order, block_nr);
350 return NULL;
351}
352
353static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req,
354 bool closing, bool tx_ring)
355{
356 struct netlink_sock *nlk = nlk_sk(sk);
357 struct netlink_ring *ring;
358 struct sk_buff_head *queue;
359 void **pg_vec = NULL;
360 unsigned int order = 0;
361 int err;
362
363 ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring;
364 queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
365
366 if (!closing) {
367 if (atomic_read(&nlk->mapped))
368 return -EBUSY;
369 if (atomic_read(&ring->pending))
370 return -EBUSY;
371 }
372
373 if (req->nm_block_nr) {
374 if (ring->pg_vec != NULL)
375 return -EBUSY;
376
377 if ((int)req->nm_block_size <= 0)
378 return -EINVAL;
379 if (!IS_ALIGNED(req->nm_block_size, PAGE_SIZE))
380 return -EINVAL;
381 if (req->nm_frame_size < NL_MMAP_HDRLEN)
382 return -EINVAL;
383 if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT))
384 return -EINVAL;
385
386 ring->frames_per_block = req->nm_block_size /
387 req->nm_frame_size;
388 if (ring->frames_per_block == 0)
389 return -EINVAL;
390 if (ring->frames_per_block * req->nm_block_nr !=
391 req->nm_frame_nr)
392 return -EINVAL;
393
394 order = get_order(req->nm_block_size);
395 pg_vec = alloc_pg_vec(nlk, req, order);
396 if (pg_vec == NULL)
397 return -ENOMEM;
398 } else {
399 if (req->nm_frame_nr)
400 return -EINVAL;
401 }
402
403 err = -EBUSY;
404 mutex_lock(&nlk->pg_vec_lock);
405 if (closing || atomic_read(&nlk->mapped) == 0) {
406 err = 0;
407 spin_lock_bh(&queue->lock);
408
409 ring->frame_max = req->nm_frame_nr - 1;
410 ring->head = 0;
411 ring->frame_size = req->nm_frame_size;
412 ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE;
413
414 swap(ring->pg_vec_len, req->nm_block_nr);
415 swap(ring->pg_vec_order, order);
416 swap(ring->pg_vec, pg_vec);
417
418 __skb_queue_purge(queue);
419 spin_unlock_bh(&queue->lock);
420
421 WARN_ON(atomic_read(&nlk->mapped));
422 }
423 mutex_unlock(&nlk->pg_vec_lock);
424
425 if (pg_vec)
426 free_pg_vec(pg_vec, order, req->nm_block_nr);
427 return err;
428}
429
430static void netlink_mm_open(struct vm_area_struct *vma)
431{
432 struct file *file = vma->vm_file;
433 struct socket *sock = file->private_data;
434 struct sock *sk = sock->sk;
435
436 if (sk)
437 atomic_inc(&nlk_sk(sk)->mapped);
438}
439
440static void netlink_mm_close(struct vm_area_struct *vma)
441{
442 struct file *file = vma->vm_file;
443 struct socket *sock = file->private_data;
444 struct sock *sk = sock->sk;
445
446 if (sk)
447 atomic_dec(&nlk_sk(sk)->mapped);
448}
449
450static const struct vm_operations_struct netlink_mmap_ops = {
451 .open = netlink_mm_open,
452 .close = netlink_mm_close,
453};
454
455static int netlink_mmap(struct file *file, struct socket *sock,
456 struct vm_area_struct *vma)
457{
458 struct sock *sk = sock->sk;
459 struct netlink_sock *nlk = nlk_sk(sk);
460 struct netlink_ring *ring;
461 unsigned long start, size, expected;
462 unsigned int i;
463 int err = -EINVAL;
464
465 if (vma->vm_pgoff)
466 return -EINVAL;
467
468 mutex_lock(&nlk->pg_vec_lock);
469
470 expected = 0;
471 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
472 if (ring->pg_vec == NULL)
473 continue;
474 expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE;
475 }
476
477 if (expected == 0)
478 goto out;
479
480 size = vma->vm_end - vma->vm_start;
481 if (size != expected)
482 goto out;
483
484 start = vma->vm_start;
485 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
486 if (ring->pg_vec == NULL)
487 continue;
488
489 for (i = 0; i < ring->pg_vec_len; i++) {
490 struct page *page;
491 void *kaddr = ring->pg_vec[i];
492 unsigned int pg_num;
493
494 for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) {
495 page = pgvec_to_page(kaddr);
496 err = vm_insert_page(vma, start, page);
497 if (err < 0)
498 goto out;
499 start += PAGE_SIZE;
500 kaddr += PAGE_SIZE;
501 }
502 }
503 }
504
505 atomic_inc(&nlk->mapped);
506 vma->vm_ops = &netlink_mmap_ops;
507 err = 0;
508out:
509 mutex_unlock(&nlk->pg_vec_lock);
510 return err;
511}
512
513static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr)
514{
515#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
516 struct page *p_start, *p_end;
517
518 /* First page is flushed through netlink_{get,set}_status */
519 p_start = pgvec_to_page(hdr + PAGE_SIZE);
520 p_end = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + hdr->nm_len - 1);
521 while (p_start <= p_end) {
522 flush_dcache_page(p_start);
523 p_start++;
524 }
525#endif
526}
527
528static enum nl_mmap_status netlink_get_status(const struct nl_mmap_hdr *hdr)
529{
530 smp_rmb();
531 flush_dcache_page(pgvec_to_page(hdr));
532 return hdr->nm_status;
533}
534
535static void netlink_set_status(struct nl_mmap_hdr *hdr,
536 enum nl_mmap_status status)
537{
538 hdr->nm_status = status;
539 flush_dcache_page(pgvec_to_page(hdr));
540 smp_wmb();
541}
542
543static struct nl_mmap_hdr *
544__netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos)
545{
546 unsigned int pg_vec_pos, frame_off;
547
548 pg_vec_pos = pos / ring->frames_per_block;
549 frame_off = pos % ring->frames_per_block;
550
551 return ring->pg_vec[pg_vec_pos] + (frame_off * ring->frame_size);
552}
553
554static struct nl_mmap_hdr *
555netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos,
556 enum nl_mmap_status status)
557{
558 struct nl_mmap_hdr *hdr;
559
560 hdr = __netlink_lookup_frame(ring, pos);
561 if (netlink_get_status(hdr) != status)
562 return NULL;
563
564 return hdr;
565}
566
567static struct nl_mmap_hdr *
568netlink_current_frame(const struct netlink_ring *ring,
569 enum nl_mmap_status status)
570{
571 return netlink_lookup_frame(ring, ring->head, status);
572}
573
574static struct nl_mmap_hdr *
575netlink_previous_frame(const struct netlink_ring *ring,
576 enum nl_mmap_status status)
577{
578 unsigned int prev;
579
580 prev = ring->head ? ring->head - 1 : ring->frame_max;
581 return netlink_lookup_frame(ring, prev, status);
582}
583
584static void netlink_increment_head(struct netlink_ring *ring)
585{
586 ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0;
587}
588
589static void netlink_forward_ring(struct netlink_ring *ring)
590{
591 unsigned int head = ring->head, pos = head;
592 const struct nl_mmap_hdr *hdr;
593
594 do {
595 hdr = __netlink_lookup_frame(ring, pos);
596 if (hdr->nm_status == NL_MMAP_STATUS_UNUSED)
597 break;
598 if (hdr->nm_status != NL_MMAP_STATUS_SKIP)
599 break;
600 netlink_increment_head(ring);
601 } while (ring->head != head);
602}
603
604static bool netlink_dump_space(struct netlink_sock *nlk)
605{
606 struct netlink_ring *ring = &nlk->rx_ring;
607 struct nl_mmap_hdr *hdr;
608 unsigned int n;
609
610 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
611 if (hdr == NULL)
612 return false;
613
614 n = ring->head + ring->frame_max / 2;
615 if (n > ring->frame_max)
616 n -= ring->frame_max;
617
618 hdr = __netlink_lookup_frame(ring, n);
619
620 return hdr->nm_status == NL_MMAP_STATUS_UNUSED;
621}
622
623static unsigned int netlink_poll(struct file *file, struct socket *sock,
624 poll_table *wait)
625{
626 struct sock *sk = sock->sk;
627 struct netlink_sock *nlk = nlk_sk(sk);
628 unsigned int mask;
629 int err;
630
631 if (nlk->rx_ring.pg_vec != NULL) {
632 /* Memory mapped sockets don't call recvmsg(), so flow control
633 * for dumps is performed here. A dump is allowed to continue
634 * if at least half the ring is unused.
635 */
636 while (nlk->cb_running && netlink_dump_space(nlk)) {
637 err = netlink_dump(sk);
638 if (err < 0) {
639 sk->sk_err = err;
640 sk->sk_error_report(sk);
641 break;
642 }
643 }
644 netlink_rcv_wake(sk);
645 }
646
647 mask = datagram_poll(file, sock, wait);
648
649 spin_lock_bh(&sk->sk_receive_queue.lock);
650 if (nlk->rx_ring.pg_vec) {
651 netlink_forward_ring(&nlk->rx_ring);
652 if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED))
653 mask |= POLLIN | POLLRDNORM;
654 }
655 spin_unlock_bh(&sk->sk_receive_queue.lock);
656
657 spin_lock_bh(&sk->sk_write_queue.lock);
658 if (nlk->tx_ring.pg_vec) {
659 if (netlink_current_frame(&nlk->tx_ring, NL_MMAP_STATUS_UNUSED))
660 mask |= POLLOUT | POLLWRNORM;
661 }
662 spin_unlock_bh(&sk->sk_write_queue.lock);
663
664 return mask;
665}
666
667static struct nl_mmap_hdr *netlink_mmap_hdr(struct sk_buff *skb)
668{
669 return (struct nl_mmap_hdr *)(skb->head - NL_MMAP_HDRLEN);
670}
671
672static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
673 struct netlink_ring *ring,
674 struct nl_mmap_hdr *hdr)
675{
676 unsigned int size;
677 void *data;
678
679 size = ring->frame_size - NL_MMAP_HDRLEN;
680 data = (void *)hdr + NL_MMAP_HDRLEN;
681
682 skb->head = data;
683 skb->data = data;
684 skb_reset_tail_pointer(skb);
685 skb->end = skb->tail + size;
686 skb->len = 0;
687
688 skb->destructor = netlink_skb_destructor;
689 NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
690 NETLINK_CB(skb).sk = sk;
691}
692
693static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
694 u32 dst_portid, u32 dst_group,
695 struct sock_iocb *siocb)
696{
697 struct netlink_sock *nlk = nlk_sk(sk);
698 struct netlink_ring *ring;
699 struct nl_mmap_hdr *hdr;
700 struct sk_buff *skb;
701 unsigned int maxlen;
702 bool excl = true;
703 int err = 0, len = 0;
704
705 /* Netlink messages are validated by the receiver before processing.
706 * In order to avoid userspace changing the contents of the message
707 * after validation, the socket and the ring may only be used by a
708 * single process, otherwise we fall back to copying.
709 */
710 if (atomic_long_read(&sk->sk_socket->file->f_count) > 2 ||
711 atomic_read(&nlk->mapped) > 1)
712 excl = false;
713
714 mutex_lock(&nlk->pg_vec_lock);
715
716 ring = &nlk->tx_ring;
717 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
718
719 do {
720 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
721 if (hdr == NULL) {
722 if (!(msg->msg_flags & MSG_DONTWAIT) &&
723 atomic_read(&nlk->tx_ring.pending))
724 schedule();
725 continue;
726 }
727 if (hdr->nm_len > maxlen) {
728 err = -EINVAL;
729 goto out;
730 }
731
732 netlink_frame_flush_dcache(hdr);
733
734 if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
735 skb = alloc_skb_head(GFP_KERNEL);
736 if (skb == NULL) {
737 err = -ENOBUFS;
738 goto out;
739 }
740 sock_hold(sk);
741 netlink_ring_setup_skb(skb, sk, ring, hdr);
742 NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
743 __skb_put(skb, hdr->nm_len);
744 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
745 atomic_inc(&ring->pending);
746 } else {
747 skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
748 if (skb == NULL) {
749 err = -ENOBUFS;
750 goto out;
751 }
752 __skb_put(skb, hdr->nm_len);
753 memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
754 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
755 }
756
757 netlink_increment_head(ring);
758
759 NETLINK_CB(skb).portid = nlk->portid;
760 NETLINK_CB(skb).dst_group = dst_group;
761 NETLINK_CB(skb).creds = siocb->scm->creds;
762
763 err = security_netlink_send(sk, skb);
764 if (err) {
765 kfree_skb(skb);
766 goto out;
767 }
768
769 if (unlikely(dst_group)) {
770 atomic_inc(&skb->users);
771 netlink_broadcast(sk, skb, dst_portid, dst_group,
772 GFP_KERNEL);
773 }
774 err = netlink_unicast(sk, skb, dst_portid,
775 msg->msg_flags & MSG_DONTWAIT);
776 if (err < 0)
777 goto out;
778 len += err;
779
780 } while (hdr != NULL ||
781 (!(msg->msg_flags & MSG_DONTWAIT) &&
782 atomic_read(&nlk->tx_ring.pending)));
783
784 if (len > 0)
785 err = len;
786out:
787 mutex_unlock(&nlk->pg_vec_lock);
788 return err;
789}
790
791static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb)
792{
793 struct nl_mmap_hdr *hdr;
794
795 hdr = netlink_mmap_hdr(skb);
796 hdr->nm_len = skb->len;
797 hdr->nm_group = NETLINK_CB(skb).dst_group;
798 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
799 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
800 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
801 netlink_frame_flush_dcache(hdr);
802 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
803
804 NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED;
805 kfree_skb(skb);
806}
807
808static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
809{
810 struct netlink_sock *nlk = nlk_sk(sk);
811 struct netlink_ring *ring = &nlk->rx_ring;
812 struct nl_mmap_hdr *hdr;
813
814 spin_lock_bh(&sk->sk_receive_queue.lock);
815 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
816 if (hdr == NULL) {
817 spin_unlock_bh(&sk->sk_receive_queue.lock);
818 kfree_skb(skb);
819 netlink_overrun(sk);
820 return;
821 }
822 netlink_increment_head(ring);
823 __skb_queue_tail(&sk->sk_receive_queue, skb);
824 spin_unlock_bh(&sk->sk_receive_queue.lock);
825
826 hdr->nm_len = skb->len;
827 hdr->nm_group = NETLINK_CB(skb).dst_group;
828 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
829 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
830 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
831 netlink_set_status(hdr, NL_MMAP_STATUS_COPY);
832}
833
834#else /* CONFIG_NETLINK_MMAP */
835#define netlink_skb_is_mmaped(skb) false
836#define netlink_rx_is_mmaped(sk) false
837#define netlink_tx_is_mmaped(sk) false
838#define netlink_mmap sock_no_mmap
839#define netlink_poll datagram_poll
840#define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
841#endif /* CONFIG_NETLINK_MMAP */
842
843static void netlink_skb_destructor(struct sk_buff *skb)
844{
845#ifdef CONFIG_NETLINK_MMAP
846 struct nl_mmap_hdr *hdr;
847 struct netlink_ring *ring;
848 struct sock *sk;
849
850 /* If a packet from the kernel to userspace was freed because of an
851 * error without being delivered to userspace, the kernel must reset
852 * the status. In the direction userspace to kernel, the status is
853 * always reset here after the packet was processed and freed.
854 */
855 if (netlink_skb_is_mmaped(skb)) {
856 hdr = netlink_mmap_hdr(skb);
857 sk = NETLINK_CB(skb).sk;
858
859 if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
860 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
861 ring = &nlk_sk(sk)->tx_ring;
862 } else {
863 if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
864 hdr->nm_len = 0;
865 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
866 }
867 ring = &nlk_sk(sk)->rx_ring;
868 }
869
870 WARN_ON(atomic_read(&ring->pending) == 0);
871 atomic_dec(&ring->pending);
872 sock_put(sk);
873
874 skb->head = NULL;
875 }
876#endif
877 if (is_vmalloc_addr(skb->head)) {
878 if (!skb->cloned ||
879 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
880 vfree(skb->head);
881
882 skb->head = NULL;
883 }
884 if (skb->sk != NULL)
885 sock_rfree(skb);
886}
887
888static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
889{
890 WARN_ON(skb->sk != NULL);
891 skb->sk = sk;
892 skb->destructor = netlink_skb_destructor;
893 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
894 sk_mem_charge(sk, skb->truesize);
895}
896
897static void netlink_sock_destruct(struct sock *sk)
898{
899 struct netlink_sock *nlk = nlk_sk(sk);
900
901 if (nlk->cb_running) {
902 if (nlk->cb.done)
903 nlk->cb.done(&nlk->cb);
904
905 module_put(nlk->cb.module);
906 kfree_skb(nlk->cb.skb);
907 }
908
909 skb_queue_purge(&sk->sk_receive_queue);
910#ifdef CONFIG_NETLINK_MMAP
911 if (1) {
912 struct nl_mmap_req req;
913
914 memset(&req, 0, sizeof(req));
915 if (nlk->rx_ring.pg_vec)
916 netlink_set_ring(sk, &req, true, false);
917 memset(&req, 0, sizeof(req));
918 if (nlk->tx_ring.pg_vec)
919 netlink_set_ring(sk, &req, true, true);
920 }
921#endif /* CONFIG_NETLINK_MMAP */
922
923 if (!sock_flag(sk, SOCK_DEAD)) {
924 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
925 return;
926 }
927
928 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
929 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
930 WARN_ON(nlk_sk(sk)->groups);
931}
932
933/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
934 * SMP. Look, when several writers sleep and reader wakes them up, all but one
935 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
936 * this, _but_ remember, it adds useless work on UP machines.
937 */
938
939void netlink_table_grab(void)
940 __acquires(nl_table_lock)
941{
942 might_sleep();
943
944 write_lock_irq(&nl_table_lock);
945
946 if (atomic_read(&nl_table_users)) {
947 DECLARE_WAITQUEUE(wait, current);
948
949 add_wait_queue_exclusive(&nl_table_wait, &wait);
950 for (;;) {
951 set_current_state(TASK_UNINTERRUPTIBLE);
952 if (atomic_read(&nl_table_users) == 0)
953 break;
954 write_unlock_irq(&nl_table_lock);
955 schedule();
956 write_lock_irq(&nl_table_lock);
957 }
958
959 __set_current_state(TASK_RUNNING);
960 remove_wait_queue(&nl_table_wait, &wait);
961 }
962}
963
964void netlink_table_ungrab(void)
965 __releases(nl_table_lock)
966{
967 write_unlock_irq(&nl_table_lock);
968 wake_up(&nl_table_wait);
969}
970
971static inline void
972netlink_lock_table(void)
973{
974 /* read_lock() synchronizes us to netlink_table_grab */
975
976 read_lock(&nl_table_lock);
977 atomic_inc(&nl_table_users);
978 read_unlock(&nl_table_lock);
979}
980
981static inline void
982netlink_unlock_table(void)
983{
984 if (atomic_dec_and_test(&nl_table_users))
985 wake_up(&nl_table_wait);
986}
987
988static bool netlink_compare(struct net *net, struct sock *sk)
989{
990 return net_eq(sock_net(sk), net);
991}
992
993static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
994{
995 struct netlink_table *table = &nl_table[protocol];
996 struct nl_portid_hash *hash = &table->hash;
997 struct hlist_head *head;
998 struct sock *sk;
999
1000 read_lock(&nl_table_lock);
1001 head = nl_portid_hashfn(hash, portid);
1002 sk_for_each(sk, head) {
1003 if (table->compare(net, sk) &&
1004 (nlk_sk(sk)->portid == portid)) {
1005 sock_hold(sk);
1006 goto found;
1007 }
1008 }
1009 sk = NULL;
1010found:
1011 read_unlock(&nl_table_lock);
1012 return sk;
1013}
1014
1015static struct hlist_head *nl_portid_hash_zalloc(size_t size)
1016{
1017 if (size <= PAGE_SIZE)
1018 return kzalloc(size, GFP_ATOMIC);
1019 else
1020 return (struct hlist_head *)
1021 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
1022 get_order(size));
1023}
1024
1025static void nl_portid_hash_free(struct hlist_head *table, size_t size)
1026{
1027 if (size <= PAGE_SIZE)
1028 kfree(table);
1029 else
1030 free_pages((unsigned long)table, get_order(size));
1031}
1032
1033static int nl_portid_hash_rehash(struct nl_portid_hash *hash, int grow)
1034{
1035 unsigned int omask, mask, shift;
1036 size_t osize, size;
1037 struct hlist_head *otable, *table;
1038 int i;
1039
1040 omask = mask = hash->mask;
1041 osize = size = (mask + 1) * sizeof(*table);
1042 shift = hash->shift;
1043
1044 if (grow) {
1045 if (++shift > hash->max_shift)
1046 return 0;
1047 mask = mask * 2 + 1;
1048 size *= 2;
1049 }
1050
1051 table = nl_portid_hash_zalloc(size);
1052 if (!table)
1053 return 0;
1054
1055 otable = hash->table;
1056 hash->table = table;
1057 hash->mask = mask;
1058 hash->shift = shift;
1059 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
1060
1061 for (i = 0; i <= omask; i++) {
1062 struct sock *sk;
1063 struct hlist_node *tmp;
1064
1065 sk_for_each_safe(sk, tmp, &otable[i])
1066 __sk_add_node(sk, nl_portid_hashfn(hash, nlk_sk(sk)->portid));
1067 }
1068
1069 nl_portid_hash_free(otable, osize);
1070 hash->rehash_time = jiffies + 10 * 60 * HZ;
1071 return 1;
1072}
1073
1074static inline int nl_portid_hash_dilute(struct nl_portid_hash *hash, int len)
1075{
1076 int avg = hash->entries >> hash->shift;
1077
1078 if (unlikely(avg > 1) && nl_portid_hash_rehash(hash, 1))
1079 return 1;
1080
1081 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
1082 nl_portid_hash_rehash(hash, 0);
1083 return 1;
1084 }
1085
1086 return 0;
1087}
1088
1089static const struct proto_ops netlink_ops;
1090
1091static void
1092netlink_update_listeners(struct sock *sk)
1093{
1094 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1095 unsigned long mask;
1096 unsigned int i;
1097 struct listeners *listeners;
1098
1099 listeners = nl_deref_protected(tbl->listeners);
1100 if (!listeners)
1101 return;
1102
1103 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
1104 mask = 0;
1105 sk_for_each_bound(sk, &tbl->mc_list) {
1106 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
1107 mask |= nlk_sk(sk)->groups[i];
1108 }
1109 listeners->masks[i] = mask;
1110 }
1111 /* this function is only called with the netlink table "grabbed", which
1112 * makes sure updates are visible before bind or setsockopt return. */
1113}
1114
1115static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
1116{
1117 struct netlink_table *table = &nl_table[sk->sk_protocol];
1118 struct nl_portid_hash *hash = &table->hash;
1119 struct hlist_head *head;
1120 int err = -EADDRINUSE;
1121 struct sock *osk;
1122 int len;
1123
1124 netlink_table_grab();
1125 head = nl_portid_hashfn(hash, portid);
1126 len = 0;
1127 sk_for_each(osk, head) {
1128 if (table->compare(net, osk) &&
1129 (nlk_sk(osk)->portid == portid))
1130 break;
1131 len++;
1132 }
1133 if (osk)
1134 goto err;
1135
1136 err = -EBUSY;
1137 if (nlk_sk(sk)->portid)
1138 goto err;
1139
1140 err = -ENOMEM;
1141 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
1142 goto err;
1143
1144 if (len && nl_portid_hash_dilute(hash, len))
1145 head = nl_portid_hashfn(hash, portid);
1146 hash->entries++;
1147 nlk_sk(sk)->portid = portid;
1148 sk_add_node(sk, head);
1149 err = 0;
1150
1151err:
1152 netlink_table_ungrab();
1153 return err;
1154}
1155
1156static void netlink_remove(struct sock *sk)
1157{
1158 netlink_table_grab();
1159 if (sk_del_node_init(sk))
1160 nl_table[sk->sk_protocol].hash.entries--;
1161 if (nlk_sk(sk)->subscriptions)
1162 __sk_del_bind_node(sk);
1163 netlink_table_ungrab();
1164}
1165
1166static struct proto netlink_proto = {
1167 .name = "NETLINK",
1168 .owner = THIS_MODULE,
1169 .obj_size = sizeof(struct netlink_sock),
1170};
1171
1172static int __netlink_create(struct net *net, struct socket *sock,
1173 struct mutex *cb_mutex, int protocol)
1174{
1175 struct sock *sk;
1176 struct netlink_sock *nlk;
1177
1178 sock->ops = &netlink_ops;
1179
1180 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
1181 if (!sk)
1182 return -ENOMEM;
1183
1184 sock_init_data(sock, sk);
1185
1186 nlk = nlk_sk(sk);
1187 if (cb_mutex) {
1188 nlk->cb_mutex = cb_mutex;
1189 } else {
1190 nlk->cb_mutex = &nlk->cb_def_mutex;
1191 mutex_init(nlk->cb_mutex);
1192 }
1193 init_waitqueue_head(&nlk->wait);
1194#ifdef CONFIG_NETLINK_MMAP
1195 mutex_init(&nlk->pg_vec_lock);
1196#endif
1197
1198 sk->sk_destruct = netlink_sock_destruct;
1199 sk->sk_protocol = protocol;
1200 return 0;
1201}
1202
1203static int netlink_create(struct net *net, struct socket *sock, int protocol,
1204 int kern)
1205{
1206 struct module *module = NULL;
1207 struct mutex *cb_mutex;
1208 struct netlink_sock *nlk;
1209 void (*bind)(int group);
1210 int err = 0;
1211
1212 sock->state = SS_UNCONNECTED;
1213
1214 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1215 return -ESOCKTNOSUPPORT;
1216
1217 if (protocol < 0 || protocol >= MAX_LINKS)
1218 return -EPROTONOSUPPORT;
1219
1220 netlink_lock_table();
1221#ifdef CONFIG_MODULES
1222 if (!nl_table[protocol].registered) {
1223 netlink_unlock_table();
1224 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
1225 netlink_lock_table();
1226 }
1227#endif
1228 if (nl_table[protocol].registered &&
1229 try_module_get(nl_table[protocol].module))
1230 module = nl_table[protocol].module;
1231 else
1232 err = -EPROTONOSUPPORT;
1233 cb_mutex = nl_table[protocol].cb_mutex;
1234 bind = nl_table[protocol].bind;
1235 netlink_unlock_table();
1236
1237 if (err < 0)
1238 goto out;
1239
1240 err = __netlink_create(net, sock, cb_mutex, protocol);
1241 if (err < 0)
1242 goto out_module;
1243
1244 local_bh_disable();
1245 sock_prot_inuse_add(net, &netlink_proto, 1);
1246 local_bh_enable();
1247
1248 nlk = nlk_sk(sock->sk);
1249 nlk->module = module;
1250 nlk->netlink_bind = bind;
1251out:
1252 return err;
1253
1254out_module:
1255 module_put(module);
1256 goto out;
1257}
1258
1259static int netlink_release(struct socket *sock)
1260{
1261 struct sock *sk = sock->sk;
1262 struct netlink_sock *nlk;
1263
1264 if (!sk)
1265 return 0;
1266
1267 netlink_remove(sk);
1268 sock_orphan(sk);
1269 nlk = nlk_sk(sk);
1270
1271 /*
1272 * OK. Socket is unlinked, any packets that arrive now
1273 * will be purged.
1274 */
1275
1276 sock->sk = NULL;
1277 wake_up_interruptible_all(&nlk->wait);
1278
1279 skb_queue_purge(&sk->sk_write_queue);
1280
1281 if (nlk->portid) {
1282 struct netlink_notify n = {
1283 .net = sock_net(sk),
1284 .protocol = sk->sk_protocol,
1285 .portid = nlk->portid,
1286 };
1287 atomic_notifier_call_chain(&netlink_chain,
1288 NETLINK_URELEASE, &n);
1289 }
1290
1291 module_put(nlk->module);
1292
1293 netlink_table_grab();
1294 if (netlink_is_kernel(sk)) {
1295 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
1296 if (--nl_table[sk->sk_protocol].registered == 0) {
1297 struct listeners *old;
1298
1299 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
1300 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
1301 kfree_rcu(old, rcu);
1302 nl_table[sk->sk_protocol].module = NULL;
1303 nl_table[sk->sk_protocol].bind = NULL;
1304 nl_table[sk->sk_protocol].flags = 0;
1305 nl_table[sk->sk_protocol].registered = 0;
1306 }
1307 } else if (nlk->subscriptions) {
1308 netlink_update_listeners(sk);
1309 }
1310 netlink_table_ungrab();
1311
1312 kfree(nlk->groups);
1313 nlk->groups = NULL;
1314
1315 local_bh_disable();
1316 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
1317 local_bh_enable();
1318 sock_put(sk);
1319 return 0;
1320}
1321
1322static int netlink_autobind(struct socket *sock)
1323{
1324 struct sock *sk = sock->sk;
1325 struct net *net = sock_net(sk);
1326 struct netlink_table *table = &nl_table[sk->sk_protocol];
1327 struct nl_portid_hash *hash = &table->hash;
1328 struct hlist_head *head;
1329 struct sock *osk;
1330 s32 portid = task_tgid_vnr(current);
1331 int err;
1332 static s32 rover = -4097;
1333
1334retry:
1335 cond_resched();
1336 netlink_table_grab();
1337 head = nl_portid_hashfn(hash, portid);
1338 sk_for_each(osk, head) {
1339 if (!table->compare(net, osk))
1340 continue;
1341 if (nlk_sk(osk)->portid == portid) {
1342 /* Bind collision, search negative portid values. */
1343 portid = rover--;
1344 if (rover > -4097)
1345 rover = -4097;
1346 netlink_table_ungrab();
1347 goto retry;
1348 }
1349 }
1350 netlink_table_ungrab();
1351
1352 err = netlink_insert(sk, net, portid);
1353 if (err == -EADDRINUSE)
1354 goto retry;
1355
1356 /* If 2 threads race to autobind, that is fine. */
1357 if (err == -EBUSY)
1358 err = 0;
1359
1360 return err;
1361}
1362
1363/**
1364 * __netlink_ns_capable - General netlink message capability test
1365 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
1366 * @user_ns: The user namespace of the capability to use
1367 * @cap: The capability to use
1368 *
1369 * Test to see if the opener of the socket we received the message
1370 * from had when the netlink socket was created and the sender of the
1371 * message has has the capability @cap in the user namespace @user_ns.
1372 */
1373bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
1374 struct user_namespace *user_ns, int cap)
1375{
1376 return ((nsp->flags & NETLINK_SKB_DST) ||
1377 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
1378 ns_capable(user_ns, cap);
1379}
1380EXPORT_SYMBOL(__netlink_ns_capable);
1381
1382/**
1383 * netlink_ns_capable - General netlink message capability test
1384 * @skb: socket buffer holding a netlink command from userspace
1385 * @user_ns: The user namespace of the capability to use
1386 * @cap: The capability to use
1387 *
1388 * Test to see if the opener of the socket we received the message
1389 * from had when the netlink socket was created and the sender of the
1390 * message has has the capability @cap in the user namespace @user_ns.
1391 */
1392bool netlink_ns_capable(const struct sk_buff *skb,
1393 struct user_namespace *user_ns, int cap)
1394{
1395 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
1396}
1397EXPORT_SYMBOL(netlink_ns_capable);
1398
1399/**
1400 * netlink_capable - Netlink global message capability test
1401 * @skb: socket buffer holding a netlink command from userspace
1402 * @cap: The capability to use
1403 *
1404 * Test to see if the opener of the socket we received the message
1405 * from had when the netlink socket was created and the sender of the
1406 * message has has the capability @cap in all user namespaces.
1407 */
1408bool netlink_capable(const struct sk_buff *skb, int cap)
1409{
1410 return netlink_ns_capable(skb, &init_user_ns, cap);
1411}
1412EXPORT_SYMBOL(netlink_capable);
1413
1414/**
1415 * netlink_net_capable - Netlink network namespace message capability test
1416 * @skb: socket buffer holding a netlink command from userspace
1417 * @cap: The capability to use
1418 *
1419 * Test to see if the opener of the socket we received the message
1420 * from had when the netlink socket was created and the sender of the
1421 * message has has the capability @cap over the network namespace of
1422 * the socket we received the message from.
1423 */
1424bool netlink_net_capable(const struct sk_buff *skb, int cap)
1425{
1426 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
1427}
1428EXPORT_SYMBOL(netlink_net_capable);
1429
1430static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
1431{
1432 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
1433 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
1434}
1435
1436static void
1437netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
1438{
1439 struct netlink_sock *nlk = nlk_sk(sk);
1440
1441 if (nlk->subscriptions && !subscriptions)
1442 __sk_del_bind_node(sk);
1443 else if (!nlk->subscriptions && subscriptions)
1444 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
1445 nlk->subscriptions = subscriptions;
1446}
1447
1448static int netlink_realloc_groups(struct sock *sk)
1449{
1450 struct netlink_sock *nlk = nlk_sk(sk);
1451 unsigned int groups;
1452 unsigned long *new_groups;
1453 int err = 0;
1454
1455 netlink_table_grab();
1456
1457 groups = nl_table[sk->sk_protocol].groups;
1458 if (!nl_table[sk->sk_protocol].registered) {
1459 err = -ENOENT;
1460 goto out_unlock;
1461 }
1462
1463 if (nlk->ngroups >= groups)
1464 goto out_unlock;
1465
1466 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
1467 if (new_groups == NULL) {
1468 err = -ENOMEM;
1469 goto out_unlock;
1470 }
1471 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
1472 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
1473
1474 nlk->groups = new_groups;
1475 nlk->ngroups = groups;
1476 out_unlock:
1477 netlink_table_ungrab();
1478 return err;
1479}
1480
1481static int netlink_bind(struct socket *sock, struct sockaddr *addr,
1482 int addr_len)
1483{
1484 struct sock *sk = sock->sk;
1485 struct net *net = sock_net(sk);
1486 struct netlink_sock *nlk = nlk_sk(sk);
1487 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1488 int err;
1489
1490 if (addr_len < sizeof(struct sockaddr_nl))
1491 return -EINVAL;
1492
1493 if (nladdr->nl_family != AF_NETLINK)
1494 return -EINVAL;
1495
1496 /* Only superuser is allowed to listen multicasts */
1497 if (nladdr->nl_groups) {
1498 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1499 return -EPERM;
1500 err = netlink_realloc_groups(sk);
1501 if (err)
1502 return err;
1503 }
1504
1505 if (nlk->portid) {
1506 if (nladdr->nl_pid != nlk->portid)
1507 return -EINVAL;
1508 } else {
1509 err = nladdr->nl_pid ?
1510 netlink_insert(sk, net, nladdr->nl_pid) :
1511 netlink_autobind(sock);
1512 if (err)
1513 return err;
1514 }
1515
1516 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1517 return 0;
1518
1519 netlink_table_grab();
1520 netlink_update_subscriptions(sk, nlk->subscriptions +
1521 hweight32(nladdr->nl_groups) -
1522 hweight32(nlk->groups[0]));
1523 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
1524 netlink_update_listeners(sk);
1525 netlink_table_ungrab();
1526
1527 if (nlk->netlink_bind && nlk->groups[0]) {
1528 int i;
1529
1530 for (i = 0; i < nlk->ngroups; i++) {
1531 if (test_bit(i, nlk->groups))
1532 nlk->netlink_bind(i);
1533 }
1534 }
1535
1536 return 0;
1537}
1538
1539static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1540 int alen, int flags)
1541{
1542 int err = 0;
1543 struct sock *sk = sock->sk;
1544 struct netlink_sock *nlk = nlk_sk(sk);
1545 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1546
1547 if (alen < sizeof(addr->sa_family))
1548 return -EINVAL;
1549
1550 if (addr->sa_family == AF_UNSPEC) {
1551 sk->sk_state = NETLINK_UNCONNECTED;
1552 nlk->dst_portid = 0;
1553 nlk->dst_group = 0;
1554 return 0;
1555 }
1556 if (addr->sa_family != AF_NETLINK)
1557 return -EINVAL;
1558
1559 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1560 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1561 return -EPERM;
1562
1563 if (!nlk->portid)
1564 err = netlink_autobind(sock);
1565
1566 if (err == 0) {
1567 sk->sk_state = NETLINK_CONNECTED;
1568 nlk->dst_portid = nladdr->nl_pid;
1569 nlk->dst_group = ffs(nladdr->nl_groups);
1570 }
1571
1572 return err;
1573}
1574
1575static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1576 int *addr_len, int peer)
1577{
1578 struct sock *sk = sock->sk;
1579 struct netlink_sock *nlk = nlk_sk(sk);
1580 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1581
1582 nladdr->nl_family = AF_NETLINK;
1583 nladdr->nl_pad = 0;
1584 *addr_len = sizeof(*nladdr);
1585
1586 if (peer) {
1587 nladdr->nl_pid = nlk->dst_portid;
1588 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1589 } else {
1590 nladdr->nl_pid = nlk->portid;
1591 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1592 }
1593 return 0;
1594}
1595
1596static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1597{
1598 struct sock *sock;
1599 struct netlink_sock *nlk;
1600
1601 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1602 if (!sock)
1603 return ERR_PTR(-ECONNREFUSED);
1604
1605 /* Don't bother queuing skb if kernel socket has no input function */
1606 nlk = nlk_sk(sock);
1607 if (sock->sk_state == NETLINK_CONNECTED &&
1608 nlk->dst_portid != nlk_sk(ssk)->portid) {
1609 sock_put(sock);
1610 return ERR_PTR(-ECONNREFUSED);
1611 }
1612 return sock;
1613}
1614
1615struct sock *netlink_getsockbyfilp(struct file *filp)
1616{
1617 struct inode *inode = file_inode(filp);
1618 struct sock *sock;
1619
1620 if (!S_ISSOCK(inode->i_mode))
1621 return ERR_PTR(-ENOTSOCK);
1622
1623 sock = SOCKET_I(inode)->sk;
1624 if (sock->sk_family != AF_NETLINK)
1625 return ERR_PTR(-EINVAL);
1626
1627 sock_hold(sock);
1628 return sock;
1629}
1630
1631static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1632 int broadcast)
1633{
1634 struct sk_buff *skb;
1635 void *data;
1636
1637 if (size <= NLMSG_GOODSIZE || broadcast)
1638 return alloc_skb(size, GFP_KERNEL);
1639
1640 size = SKB_DATA_ALIGN(size) +
1641 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1642
1643 data = vmalloc(size);
1644 if (data == NULL)
1645 return NULL;
1646
1647 skb = build_skb(data, size);
1648 if (skb == NULL)
1649 vfree(data);
1650 else {
1651 skb->head_frag = 0;
1652 skb->destructor = netlink_skb_destructor;
1653 }
1654
1655 return skb;
1656}
1657
1658/*
1659 * Attach a skb to a netlink socket.
1660 * The caller must hold a reference to the destination socket. On error, the
1661 * reference is dropped. The skb is not send to the destination, just all
1662 * all error checks are performed and memory in the queue is reserved.
1663 * Return values:
1664 * < 0: error. skb freed, reference to sock dropped.
1665 * 0: continue
1666 * 1: repeat lookup - reference dropped while waiting for socket memory.
1667 */
1668int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1669 long *timeo, struct sock *ssk)
1670{
1671 struct netlink_sock *nlk;
1672
1673 nlk = nlk_sk(sk);
1674
1675 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1676 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1677 !netlink_skb_is_mmaped(skb)) {
1678 DECLARE_WAITQUEUE(wait, current);
1679 if (!*timeo) {
1680 if (!ssk || netlink_is_kernel(ssk))
1681 netlink_overrun(sk);
1682 sock_put(sk);
1683 kfree_skb(skb);
1684 return -EAGAIN;
1685 }
1686
1687 __set_current_state(TASK_INTERRUPTIBLE);
1688 add_wait_queue(&nlk->wait, &wait);
1689
1690 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1691 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1692 !sock_flag(sk, SOCK_DEAD))
1693 *timeo = schedule_timeout(*timeo);
1694
1695 __set_current_state(TASK_RUNNING);
1696 remove_wait_queue(&nlk->wait, &wait);
1697 sock_put(sk);
1698
1699 if (signal_pending(current)) {
1700 kfree_skb(skb);
1701 return sock_intr_errno(*timeo);
1702 }
1703 return 1;
1704 }
1705 netlink_skb_set_owner_r(skb, sk);
1706 return 0;
1707}
1708
1709static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1710{
1711 int len = skb->len;
1712
1713 netlink_deliver_tap(skb);
1714
1715#ifdef CONFIG_NETLINK_MMAP
1716 if (netlink_skb_is_mmaped(skb))
1717 netlink_queue_mmaped_skb(sk, skb);
1718 else if (netlink_rx_is_mmaped(sk))
1719 netlink_ring_set_copied(sk, skb);
1720 else
1721#endif /* CONFIG_NETLINK_MMAP */
1722 skb_queue_tail(&sk->sk_receive_queue, skb);
1723 sk->sk_data_ready(sk);
1724 return len;
1725}
1726
1727int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1728{
1729 int len = __netlink_sendskb(sk, skb);
1730
1731 sock_put(sk);
1732 return len;
1733}
1734
1735void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1736{
1737 kfree_skb(skb);
1738 sock_put(sk);
1739}
1740
1741static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1742{
1743 int delta;
1744
1745 WARN_ON(skb->sk != NULL);
1746 if (netlink_skb_is_mmaped(skb))
1747 return skb;
1748
1749 delta = skb->end - skb->tail;
1750 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1751 return skb;
1752
1753 if (skb_shared(skb)) {
1754 struct sk_buff *nskb = skb_clone(skb, allocation);
1755 if (!nskb)
1756 return skb;
1757 consume_skb(skb);
1758 skb = nskb;
1759 }
1760
1761 if (!pskb_expand_head(skb, 0, -delta, allocation))
1762 skb->truesize -= delta;
1763
1764 return skb;
1765}
1766
1767static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1768 struct sock *ssk)
1769{
1770 int ret;
1771 struct netlink_sock *nlk = nlk_sk(sk);
1772
1773 ret = -ECONNREFUSED;
1774 if (nlk->netlink_rcv != NULL) {
1775 ret = skb->len;
1776 netlink_skb_set_owner_r(skb, sk);
1777 NETLINK_CB(skb).sk = ssk;
1778 netlink_deliver_tap_kernel(sk, ssk, skb);
1779 nlk->netlink_rcv(skb);
1780 consume_skb(skb);
1781 } else {
1782 kfree_skb(skb);
1783 }
1784 sock_put(sk);
1785 return ret;
1786}
1787
1788int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1789 u32 portid, int nonblock)
1790{
1791 struct sock *sk;
1792 int err;
1793 long timeo;
1794
1795 skb = netlink_trim(skb, gfp_any());
1796
1797 timeo = sock_sndtimeo(ssk, nonblock);
1798retry:
1799 sk = netlink_getsockbyportid(ssk, portid);
1800 if (IS_ERR(sk)) {
1801 kfree_skb(skb);
1802 return PTR_ERR(sk);
1803 }
1804 if (netlink_is_kernel(sk))
1805 return netlink_unicast_kernel(sk, skb, ssk);
1806
1807 if (sk_filter(sk, skb)) {
1808 err = skb->len;
1809 kfree_skb(skb);
1810 sock_put(sk);
1811 return err;
1812 }
1813
1814 err = netlink_attachskb(sk, skb, &timeo, ssk);
1815 if (err == 1)
1816 goto retry;
1817 if (err)
1818 return err;
1819
1820 return netlink_sendskb(sk, skb);
1821}
1822EXPORT_SYMBOL(netlink_unicast);
1823
1824struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
1825 u32 dst_portid, gfp_t gfp_mask)
1826{
1827#ifdef CONFIG_NETLINK_MMAP
1828 struct sock *sk = NULL;
1829 struct sk_buff *skb;
1830 struct netlink_ring *ring;
1831 struct nl_mmap_hdr *hdr;
1832 unsigned int maxlen;
1833
1834 sk = netlink_getsockbyportid(ssk, dst_portid);
1835 if (IS_ERR(sk))
1836 goto out;
1837
1838 ring = &nlk_sk(sk)->rx_ring;
1839 /* fast-path without atomic ops for common case: non-mmaped receiver */
1840 if (ring->pg_vec == NULL)
1841 goto out_put;
1842
1843 if (ring->frame_size - NL_MMAP_HDRLEN < size)
1844 goto out_put;
1845
1846 skb = alloc_skb_head(gfp_mask);
1847 if (skb == NULL)
1848 goto err1;
1849
1850 spin_lock_bh(&sk->sk_receive_queue.lock);
1851 /* check again under lock */
1852 if (ring->pg_vec == NULL)
1853 goto out_free;
1854
1855 /* check again under lock */
1856 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
1857 if (maxlen < size)
1858 goto out_free;
1859
1860 netlink_forward_ring(ring);
1861 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
1862 if (hdr == NULL)
1863 goto err2;
1864 netlink_ring_setup_skb(skb, sk, ring, hdr);
1865 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
1866 atomic_inc(&ring->pending);
1867 netlink_increment_head(ring);
1868
1869 spin_unlock_bh(&sk->sk_receive_queue.lock);
1870 return skb;
1871
1872err2:
1873 kfree_skb(skb);
1874 spin_unlock_bh(&sk->sk_receive_queue.lock);
1875 netlink_overrun(sk);
1876err1:
1877 sock_put(sk);
1878 return NULL;
1879
1880out_free:
1881 kfree_skb(skb);
1882 spin_unlock_bh(&sk->sk_receive_queue.lock);
1883out_put:
1884 sock_put(sk);
1885out:
1886#endif
1887 return alloc_skb(size, gfp_mask);
1888}
1889EXPORT_SYMBOL_GPL(netlink_alloc_skb);
1890
1891int netlink_has_listeners(struct sock *sk, unsigned int group)
1892{
1893 int res = 0;
1894 struct listeners *listeners;
1895
1896 BUG_ON(!netlink_is_kernel(sk));
1897
1898 rcu_read_lock();
1899 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1900
1901 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1902 res = test_bit(group - 1, listeners->masks);
1903
1904 rcu_read_unlock();
1905
1906 return res;
1907}
1908EXPORT_SYMBOL_GPL(netlink_has_listeners);
1909
1910static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1911{
1912 struct netlink_sock *nlk = nlk_sk(sk);
1913
1914 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1915 !test_bit(NETLINK_CONGESTED, &nlk->state)) {
1916 netlink_skb_set_owner_r(skb, sk);
1917 __netlink_sendskb(sk, skb);
1918 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1919 }
1920 return -1;
1921}
1922
1923struct netlink_broadcast_data {
1924 struct sock *exclude_sk;
1925 struct net *net;
1926 u32 portid;
1927 u32 group;
1928 int failure;
1929 int delivery_failure;
1930 int congested;
1931 int delivered;
1932 gfp_t allocation;
1933 struct sk_buff *skb, *skb2;
1934 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1935 void *tx_data;
1936};
1937
1938static int do_one_broadcast(struct sock *sk,
1939 struct netlink_broadcast_data *p)
1940{
1941 struct netlink_sock *nlk = nlk_sk(sk);
1942 int val;
1943
1944 if (p->exclude_sk == sk)
1945 goto out;
1946
1947 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1948 !test_bit(p->group - 1, nlk->groups))
1949 goto out;
1950
1951 if (!net_eq(sock_net(sk), p->net))
1952 goto out;
1953
1954 if (p->failure) {
1955 netlink_overrun(sk);
1956 goto out;
1957 }
1958
1959 sock_hold(sk);
1960 if (p->skb2 == NULL) {
1961 if (skb_shared(p->skb)) {
1962 p->skb2 = skb_clone(p->skb, p->allocation);
1963 } else {
1964 p->skb2 = skb_get(p->skb);
1965 /*
1966 * skb ownership may have been set when
1967 * delivered to a previous socket.
1968 */
1969 skb_orphan(p->skb2);
1970 }
1971 }
1972 if (p->skb2 == NULL) {
1973 netlink_overrun(sk);
1974 /* Clone failed. Notify ALL listeners. */
1975 p->failure = 1;
1976 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1977 p->delivery_failure = 1;
1978 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1979 kfree_skb(p->skb2);
1980 p->skb2 = NULL;
1981 } else if (sk_filter(sk, p->skb2)) {
1982 kfree_skb(p->skb2);
1983 p->skb2 = NULL;
1984 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1985 netlink_overrun(sk);
1986 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1987 p->delivery_failure = 1;
1988 } else {
1989 p->congested |= val;
1990 p->delivered = 1;
1991 p->skb2 = NULL;
1992 }
1993 sock_put(sk);
1994
1995out:
1996 return 0;
1997}
1998
1999int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
2000 u32 group, gfp_t allocation,
2001 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
2002 void *filter_data)
2003{
2004 struct net *net = sock_net(ssk);
2005 struct netlink_broadcast_data info;
2006 struct sock *sk;
2007
2008 skb = netlink_trim(skb, allocation);
2009
2010 info.exclude_sk = ssk;
2011 info.net = net;
2012 info.portid = portid;
2013 info.group = group;
2014 info.failure = 0;
2015 info.delivery_failure = 0;
2016 info.congested = 0;
2017 info.delivered = 0;
2018 info.allocation = allocation;
2019 info.skb = skb;
2020 info.skb2 = NULL;
2021 info.tx_filter = filter;
2022 info.tx_data = filter_data;
2023
2024 /* While we sleep in clone, do not allow to change socket list */
2025
2026 netlink_lock_table();
2027
2028 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
2029 do_one_broadcast(sk, &info);
2030
2031 consume_skb(skb);
2032
2033 netlink_unlock_table();
2034
2035 if (info.delivery_failure) {
2036 kfree_skb(info.skb2);
2037 return -ENOBUFS;
2038 }
2039 consume_skb(info.skb2);
2040
2041 if (info.delivered) {
2042 if (info.congested && (allocation & __GFP_WAIT))
2043 yield();
2044 return 0;
2045 }
2046 return -ESRCH;
2047}
2048EXPORT_SYMBOL(netlink_broadcast_filtered);
2049
2050int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
2051 u32 group, gfp_t allocation)
2052{
2053 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
2054 NULL, NULL);
2055}
2056EXPORT_SYMBOL(netlink_broadcast);
2057
2058struct netlink_set_err_data {
2059 struct sock *exclude_sk;
2060 u32 portid;
2061 u32 group;
2062 int code;
2063};
2064
2065static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
2066{
2067 struct netlink_sock *nlk = nlk_sk(sk);
2068 int ret = 0;
2069
2070 if (sk == p->exclude_sk)
2071 goto out;
2072
2073 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
2074 goto out;
2075
2076 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
2077 !test_bit(p->group - 1, nlk->groups))
2078 goto out;
2079
2080 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
2081 ret = 1;
2082 goto out;
2083 }
2084
2085 sk->sk_err = p->code;
2086 sk->sk_error_report(sk);
2087out:
2088 return ret;
2089}
2090
2091/**
2092 * netlink_set_err - report error to broadcast listeners
2093 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
2094 * @portid: the PORTID of a process that we want to skip (if any)
2095 * @group: the broadcast group that will notice the error
2096 * @code: error code, must be negative (as usual in kernelspace)
2097 *
2098 * This function returns the number of broadcast listeners that have set the
2099 * NETLINK_RECV_NO_ENOBUFS socket option.
2100 */
2101int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
2102{
2103 struct netlink_set_err_data info;
2104 struct sock *sk;
2105 int ret = 0;
2106
2107 info.exclude_sk = ssk;
2108 info.portid = portid;
2109 info.group = group;
2110 /* sk->sk_err wants a positive error value */
2111 info.code = -code;
2112
2113 read_lock(&nl_table_lock);
2114
2115 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
2116 ret += do_one_set_err(sk, &info);
2117
2118 read_unlock(&nl_table_lock);
2119 return ret;
2120}
2121EXPORT_SYMBOL(netlink_set_err);
2122
2123/* must be called with netlink table grabbed */
2124static void netlink_update_socket_mc(struct netlink_sock *nlk,
2125 unsigned int group,
2126 int is_new)
2127{
2128 int old, new = !!is_new, subscriptions;
2129
2130 old = test_bit(group - 1, nlk->groups);
2131 subscriptions = nlk->subscriptions - old + new;
2132 if (new)
2133 __set_bit(group - 1, nlk->groups);
2134 else
2135 __clear_bit(group - 1, nlk->groups);
2136 netlink_update_subscriptions(&nlk->sk, subscriptions);
2137 netlink_update_listeners(&nlk->sk);
2138}
2139
2140static int netlink_setsockopt(struct socket *sock, int level, int optname,
2141 char __user *optval, unsigned int optlen)
2142{
2143 struct sock *sk = sock->sk;
2144 struct netlink_sock *nlk = nlk_sk(sk);
2145 unsigned int val = 0;
2146 int err;
2147
2148 if (level != SOL_NETLINK)
2149 return -ENOPROTOOPT;
2150
2151 if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING &&
2152 optlen >= sizeof(int) &&
2153 get_user(val, (unsigned int __user *)optval))
2154 return -EFAULT;
2155
2156 switch (optname) {
2157 case NETLINK_PKTINFO:
2158 if (val)
2159 nlk->flags |= NETLINK_RECV_PKTINFO;
2160 else
2161 nlk->flags &= ~NETLINK_RECV_PKTINFO;
2162 err = 0;
2163 break;
2164 case NETLINK_ADD_MEMBERSHIP:
2165 case NETLINK_DROP_MEMBERSHIP: {
2166 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
2167 return -EPERM;
2168 err = netlink_realloc_groups(sk);
2169 if (err)
2170 return err;
2171 if (!val || val - 1 >= nlk->ngroups)
2172 return -EINVAL;
2173 netlink_table_grab();
2174 netlink_update_socket_mc(nlk, val,
2175 optname == NETLINK_ADD_MEMBERSHIP);
2176 netlink_table_ungrab();
2177
2178 if (nlk->netlink_bind)
2179 nlk->netlink_bind(val);
2180
2181 err = 0;
2182 break;
2183 }
2184 case NETLINK_BROADCAST_ERROR:
2185 if (val)
2186 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
2187 else
2188 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
2189 err = 0;
2190 break;
2191 case NETLINK_NO_ENOBUFS:
2192 if (val) {
2193 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
2194 clear_bit(NETLINK_CONGESTED, &nlk->state);
2195 wake_up_interruptible(&nlk->wait);
2196 } else {
2197 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
2198 }
2199 err = 0;
2200 break;
2201#ifdef CONFIG_NETLINK_MMAP
2202 case NETLINK_RX_RING:
2203 case NETLINK_TX_RING: {
2204 struct nl_mmap_req req;
2205
2206 /* Rings might consume more memory than queue limits, require
2207 * CAP_NET_ADMIN.
2208 */
2209 if (!capable(CAP_NET_ADMIN))
2210 return -EPERM;
2211 if (optlen < sizeof(req))
2212 return -EINVAL;
2213 if (copy_from_user(&req, optval, sizeof(req)))
2214 return -EFAULT;
2215 err = netlink_set_ring(sk, &req, false,
2216 optname == NETLINK_TX_RING);
2217 break;
2218 }
2219#endif /* CONFIG_NETLINK_MMAP */
2220 default:
2221 err = -ENOPROTOOPT;
2222 }
2223 return err;
2224}
2225
2226static int netlink_getsockopt(struct socket *sock, int level, int optname,
2227 char __user *optval, int __user *optlen)
2228{
2229 struct sock *sk = sock->sk;
2230 struct netlink_sock *nlk = nlk_sk(sk);
2231 int len, val, err;
2232
2233 if (level != SOL_NETLINK)
2234 return -ENOPROTOOPT;
2235
2236 if (get_user(len, optlen))
2237 return -EFAULT;
2238 if (len < 0)
2239 return -EINVAL;
2240
2241 switch (optname) {
2242 case NETLINK_PKTINFO:
2243 if (len < sizeof(int))
2244 return -EINVAL;
2245 len = sizeof(int);
2246 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
2247 if (put_user(len, optlen) ||
2248 put_user(val, optval))
2249 return -EFAULT;
2250 err = 0;
2251 break;
2252 case NETLINK_BROADCAST_ERROR:
2253 if (len < sizeof(int))
2254 return -EINVAL;
2255 len = sizeof(int);
2256 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
2257 if (put_user(len, optlen) ||
2258 put_user(val, optval))
2259 return -EFAULT;
2260 err = 0;
2261 break;
2262 case NETLINK_NO_ENOBUFS:
2263 if (len < sizeof(int))
2264 return -EINVAL;
2265 len = sizeof(int);
2266 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
2267 if (put_user(len, optlen) ||
2268 put_user(val, optval))
2269 return -EFAULT;
2270 err = 0;
2271 break;
2272 default:
2273 err = -ENOPROTOOPT;
2274 }
2275 return err;
2276}
2277
2278static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
2279{
2280 struct nl_pktinfo info;
2281
2282 info.group = NETLINK_CB(skb).dst_group;
2283 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
2284}
2285
2286static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
2287 struct msghdr *msg, size_t len)
2288{
2289 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2290 struct sock *sk = sock->sk;
2291 struct netlink_sock *nlk = nlk_sk(sk);
2292 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2293 u32 dst_portid;
2294 u32 dst_group;
2295 struct sk_buff *skb;
2296 int err;
2297 struct scm_cookie scm;
2298 u32 netlink_skb_flags = 0;
2299
2300 if (msg->msg_flags&MSG_OOB)
2301 return -EOPNOTSUPP;
2302
2303 if (NULL == siocb->scm)
2304 siocb->scm = &scm;
2305
2306 err = scm_send(sock, msg, siocb->scm, true);
2307 if (err < 0)
2308 return err;
2309
2310 if (msg->msg_namelen) {
2311 err = -EINVAL;
2312 if (addr->nl_family != AF_NETLINK)
2313 goto out;
2314 dst_portid = addr->nl_pid;
2315 dst_group = ffs(addr->nl_groups);
2316 err = -EPERM;
2317 if ((dst_group || dst_portid) &&
2318 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
2319 goto out;
2320 netlink_skb_flags |= NETLINK_SKB_DST;
2321 } else {
2322 dst_portid = nlk->dst_portid;
2323 dst_group = nlk->dst_group;
2324 }
2325
2326 if (!nlk->portid) {
2327 err = netlink_autobind(sock);
2328 if (err)
2329 goto out;
2330 }
2331
2332 if (netlink_tx_is_mmaped(sk) &&
2333 msg->msg_iov->iov_base == NULL) {
2334 err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
2335 siocb);
2336 goto out;
2337 }
2338
2339 err = -EMSGSIZE;
2340 if (len > sk->sk_sndbuf - 32)
2341 goto out;
2342 err = -ENOBUFS;
2343 skb = netlink_alloc_large_skb(len, dst_group);
2344 if (skb == NULL)
2345 goto out;
2346
2347 NETLINK_CB(skb).portid = nlk->portid;
2348 NETLINK_CB(skb).dst_group = dst_group;
2349 NETLINK_CB(skb).creds = siocb->scm->creds;
2350 NETLINK_CB(skb).flags = netlink_skb_flags;
2351
2352 err = -EFAULT;
2353 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
2354 kfree_skb(skb);
2355 goto out;
2356 }
2357
2358 err = security_netlink_send(sk, skb);
2359 if (err) {
2360 kfree_skb(skb);
2361 goto out;
2362 }
2363
2364 if (dst_group) {
2365 atomic_inc(&skb->users);
2366 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
2367 }
2368 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
2369
2370out:
2371 scm_destroy(siocb->scm);
2372 return err;
2373}
2374
2375static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
2376 struct msghdr *msg, size_t len,
2377 int flags)
2378{
2379 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2380 struct scm_cookie scm;
2381 struct sock *sk = sock->sk;
2382 struct netlink_sock *nlk = nlk_sk(sk);
2383 int noblock = flags&MSG_DONTWAIT;
2384 size_t copied;
2385 struct sk_buff *skb, *data_skb;
2386 int err, ret;
2387
2388 if (flags&MSG_OOB)
2389 return -EOPNOTSUPP;
2390
2391 copied = 0;
2392
2393 skb = skb_recv_datagram(sk, flags, noblock, &err);
2394 if (skb == NULL)
2395 goto out;
2396
2397 data_skb = skb;
2398
2399#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2400 if (unlikely(skb_shinfo(skb)->frag_list)) {
2401 /*
2402 * If this skb has a frag_list, then here that means that we
2403 * will have to use the frag_list skb's data for compat tasks
2404 * and the regular skb's data for normal (non-compat) tasks.
2405 *
2406 * If we need to send the compat skb, assign it to the
2407 * 'data_skb' variable so that it will be used below for data
2408 * copying. We keep 'skb' for everything else, including
2409 * freeing both later.
2410 */
2411 if (flags & MSG_CMSG_COMPAT)
2412 data_skb = skb_shinfo(skb)->frag_list;
2413 }
2414#endif
2415
2416 /* Record the max length of recvmsg() calls for future allocations */
2417 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
2418 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
2419 16384);
2420
2421 copied = data_skb->len;
2422 if (len < copied) {
2423 msg->msg_flags |= MSG_TRUNC;
2424 copied = len;
2425 }
2426
2427 skb_reset_transport_header(data_skb);
2428 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
2429
2430 if (msg->msg_name) {
2431 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2432 addr->nl_family = AF_NETLINK;
2433 addr->nl_pad = 0;
2434 addr->nl_pid = NETLINK_CB(skb).portid;
2435 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
2436 msg->msg_namelen = sizeof(*addr);
2437 }
2438
2439 if (nlk->flags & NETLINK_RECV_PKTINFO)
2440 netlink_cmsg_recv_pktinfo(msg, skb);
2441
2442 if (NULL == siocb->scm) {
2443 memset(&scm, 0, sizeof(scm));
2444 siocb->scm = &scm;
2445 }
2446 siocb->scm->creds = *NETLINK_CREDS(skb);
2447 if (flags & MSG_TRUNC)
2448 copied = data_skb->len;
2449
2450 skb_free_datagram(sk, skb);
2451
2452 if (nlk->cb_running &&
2453 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
2454 ret = netlink_dump(sk);
2455 if (ret) {
2456 sk->sk_err = ret;
2457 sk->sk_error_report(sk);
2458 }
2459 }
2460
2461 scm_recv(sock, msg, siocb->scm, flags);
2462out:
2463 netlink_rcv_wake(sk);
2464 return err ? : copied;
2465}
2466
2467static void netlink_data_ready(struct sock *sk)
2468{
2469 BUG();
2470}
2471
2472/*
2473 * We export these functions to other modules. They provide a
2474 * complete set of kernel non-blocking support for message
2475 * queueing.
2476 */
2477
2478struct sock *
2479__netlink_kernel_create(struct net *net, int unit, struct module *module,
2480 struct netlink_kernel_cfg *cfg)
2481{
2482 struct socket *sock;
2483 struct sock *sk;
2484 struct netlink_sock *nlk;
2485 struct listeners *listeners = NULL;
2486 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2487 unsigned int groups;
2488
2489 BUG_ON(!nl_table);
2490
2491 if (unit < 0 || unit >= MAX_LINKS)
2492 return NULL;
2493
2494 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2495 return NULL;
2496
2497 /*
2498 * We have to just have a reference on the net from sk, but don't
2499 * get_net it. Besides, we cannot get and then put the net here.
2500 * So we create one inside init_net and the move it to net.
2501 */
2502
2503 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
2504 goto out_sock_release_nosk;
2505
2506 sk = sock->sk;
2507 sk_change_net(sk, net);
2508
2509 if (!cfg || cfg->groups < 32)
2510 groups = 32;
2511 else
2512 groups = cfg->groups;
2513
2514 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2515 if (!listeners)
2516 goto out_sock_release;
2517
2518 sk->sk_data_ready = netlink_data_ready;
2519 if (cfg && cfg->input)
2520 nlk_sk(sk)->netlink_rcv = cfg->input;
2521
2522 if (netlink_insert(sk, net, 0))
2523 goto out_sock_release;
2524
2525 nlk = nlk_sk(sk);
2526 nlk->flags |= NETLINK_KERNEL_SOCKET;
2527
2528 netlink_table_grab();
2529 if (!nl_table[unit].registered) {
2530 nl_table[unit].groups = groups;
2531 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2532 nl_table[unit].cb_mutex = cb_mutex;
2533 nl_table[unit].module = module;
2534 if (cfg) {
2535 nl_table[unit].bind = cfg->bind;
2536 nl_table[unit].flags = cfg->flags;
2537 if (cfg->compare)
2538 nl_table[unit].compare = cfg->compare;
2539 }
2540 nl_table[unit].registered = 1;
2541 } else {
2542 kfree(listeners);
2543 nl_table[unit].registered++;
2544 }
2545 netlink_table_ungrab();
2546 return sk;
2547
2548out_sock_release:
2549 kfree(listeners);
2550 netlink_kernel_release(sk);
2551 return NULL;
2552
2553out_sock_release_nosk:
2554 sock_release(sock);
2555 return NULL;
2556}
2557EXPORT_SYMBOL(__netlink_kernel_create);
2558
2559void
2560netlink_kernel_release(struct sock *sk)
2561{
2562 sk_release_kernel(sk);
2563}
2564EXPORT_SYMBOL(netlink_kernel_release);
2565
2566int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2567{
2568 struct listeners *new, *old;
2569 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2570
2571 if (groups < 32)
2572 groups = 32;
2573
2574 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2575 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2576 if (!new)
2577 return -ENOMEM;
2578 old = nl_deref_protected(tbl->listeners);
2579 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2580 rcu_assign_pointer(tbl->listeners, new);
2581
2582 kfree_rcu(old, rcu);
2583 }
2584 tbl->groups = groups;
2585
2586 return 0;
2587}
2588
2589/**
2590 * netlink_change_ngroups - change number of multicast groups
2591 *
2592 * This changes the number of multicast groups that are available
2593 * on a certain netlink family. Note that it is not possible to
2594 * change the number of groups to below 32. Also note that it does
2595 * not implicitly call netlink_clear_multicast_users() when the
2596 * number of groups is reduced.
2597 *
2598 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2599 * @groups: The new number of groups.
2600 */
2601int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2602{
2603 int err;
2604
2605 netlink_table_grab();
2606 err = __netlink_change_ngroups(sk, groups);
2607 netlink_table_ungrab();
2608
2609 return err;
2610}
2611
2612void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2613{
2614 struct sock *sk;
2615 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2616
2617 sk_for_each_bound(sk, &tbl->mc_list)
2618 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2619}
2620
2621struct nlmsghdr *
2622__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2623{
2624 struct nlmsghdr *nlh;
2625 int size = nlmsg_msg_size(len);
2626
2627 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2628 nlh->nlmsg_type = type;
2629 nlh->nlmsg_len = size;
2630 nlh->nlmsg_flags = flags;
2631 nlh->nlmsg_pid = portid;
2632 nlh->nlmsg_seq = seq;
2633 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2634 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2635 return nlh;
2636}
2637EXPORT_SYMBOL(__nlmsg_put);
2638
2639/*
2640 * It looks a bit ugly.
2641 * It would be better to create kernel thread.
2642 */
2643
2644static int netlink_dump(struct sock *sk)
2645{
2646 struct netlink_sock *nlk = nlk_sk(sk);
2647 struct netlink_callback *cb;
2648 struct sk_buff *skb = NULL;
2649 struct nlmsghdr *nlh;
2650 int len, err = -ENOBUFS;
2651 int alloc_size;
2652
2653 mutex_lock(nlk->cb_mutex);
2654 if (!nlk->cb_running) {
2655 err = -EINVAL;
2656 goto errout_skb;
2657 }
2658
2659 cb = &nlk->cb;
2660 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2661
2662 if (!netlink_rx_is_mmaped(sk) &&
2663 atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2664 goto errout_skb;
2665
2666 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2667 * required, but it makes sense to _attempt_ a 16K bytes allocation
2668 * to reduce number of system calls on dump operations, if user
2669 * ever provided a big enough buffer.
2670 */
2671 if (alloc_size < nlk->max_recvmsg_len) {
2672 skb = netlink_alloc_skb(sk,
2673 nlk->max_recvmsg_len,
2674 nlk->portid,
2675 GFP_KERNEL |
2676 __GFP_NOWARN |
2677 __GFP_NORETRY);
2678 /* available room should be exact amount to avoid MSG_TRUNC */
2679 if (skb)
2680 skb_reserve(skb, skb_tailroom(skb) -
2681 nlk->max_recvmsg_len);
2682 }
2683 if (!skb)
2684 skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
2685 GFP_KERNEL);
2686 if (!skb)
2687 goto errout_skb;
2688 netlink_skb_set_owner_r(skb, sk);
2689
2690 len = cb->dump(skb, cb);
2691
2692 if (len > 0) {
2693 mutex_unlock(nlk->cb_mutex);
2694
2695 if (sk_filter(sk, skb))
2696 kfree_skb(skb);
2697 else
2698 __netlink_sendskb(sk, skb);
2699 return 0;
2700 }
2701
2702 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2703 if (!nlh)
2704 goto errout_skb;
2705
2706 nl_dump_check_consistent(cb, nlh);
2707
2708 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2709
2710 if (sk_filter(sk, skb))
2711 kfree_skb(skb);
2712 else
2713 __netlink_sendskb(sk, skb);
2714
2715 if (cb->done)
2716 cb->done(cb);
2717
2718 nlk->cb_running = false;
2719 mutex_unlock(nlk->cb_mutex);
2720 module_put(cb->module);
2721 consume_skb(cb->skb);
2722 return 0;
2723
2724errout_skb:
2725 mutex_unlock(nlk->cb_mutex);
2726 kfree_skb(skb);
2727 return err;
2728}
2729
2730int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2731 const struct nlmsghdr *nlh,
2732 struct netlink_dump_control *control)
2733{
2734 struct netlink_callback *cb;
2735 struct sock *sk;
2736 struct netlink_sock *nlk;
2737 int ret;
2738
2739 /* Memory mapped dump requests need to be copied to avoid looping
2740 * on the pending state in netlink_mmap_sendmsg() while the CB hold
2741 * a reference to the skb.
2742 */
2743 if (netlink_skb_is_mmaped(skb)) {
2744 skb = skb_copy(skb, GFP_KERNEL);
2745 if (skb == NULL)
2746 return -ENOBUFS;
2747 } else
2748 atomic_inc(&skb->users);
2749
2750 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2751 if (sk == NULL) {
2752 ret = -ECONNREFUSED;
2753 goto error_free;
2754 }
2755
2756 nlk = nlk_sk(sk);
2757 mutex_lock(nlk->cb_mutex);
2758 /* A dump is in progress... */
2759 if (nlk->cb_running) {
2760 ret = -EBUSY;
2761 goto error_unlock;
2762 }
2763 /* add reference of module which cb->dump belongs to */
2764 if (!try_module_get(control->module)) {
2765 ret = -EPROTONOSUPPORT;
2766 goto error_unlock;
2767 }
2768
2769 cb = &nlk->cb;
2770 memset(cb, 0, sizeof(*cb));
2771 cb->dump = control->dump;
2772 cb->done = control->done;
2773 cb->nlh = nlh;
2774 cb->data = control->data;
2775 cb->module = control->module;
2776 cb->min_dump_alloc = control->min_dump_alloc;
2777 cb->skb = skb;
2778
2779 nlk->cb_running = true;
2780
2781 mutex_unlock(nlk->cb_mutex);
2782
2783 ret = netlink_dump(sk);
2784 sock_put(sk);
2785
2786 if (ret)
2787 return ret;
2788
2789 /* We successfully started a dump, by returning -EINTR we
2790 * signal not to send ACK even if it was requested.
2791 */
2792 return -EINTR;
2793
2794error_unlock:
2795 sock_put(sk);
2796 mutex_unlock(nlk->cb_mutex);
2797error_free:
2798 kfree_skb(skb);
2799 return ret;
2800}
2801EXPORT_SYMBOL(__netlink_dump_start);
2802
2803void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2804{
2805 struct sk_buff *skb;
2806 struct nlmsghdr *rep;
2807 struct nlmsgerr *errmsg;
2808 size_t payload = sizeof(*errmsg);
2809
2810 /* error messages get the original request appened */
2811 if (err)
2812 payload += nlmsg_len(nlh);
2813
2814 skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
2815 NETLINK_CB(in_skb).portid, GFP_KERNEL);
2816 if (!skb) {
2817 struct sock *sk;
2818
2819 sk = netlink_lookup(sock_net(in_skb->sk),
2820 in_skb->sk->sk_protocol,
2821 NETLINK_CB(in_skb).portid);
2822 if (sk) {
2823 sk->sk_err = ENOBUFS;
2824 sk->sk_error_report(sk);
2825 sock_put(sk);
2826 }
2827 return;
2828 }
2829
2830 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2831 NLMSG_ERROR, payload, 0);
2832 errmsg = nlmsg_data(rep);
2833 errmsg->error = err;
2834 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
2835 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2836}
2837EXPORT_SYMBOL(netlink_ack);
2838
2839int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2840 struct nlmsghdr *))
2841{
2842 struct nlmsghdr *nlh;
2843 int err;
2844
2845 while (skb->len >= nlmsg_total_size(0)) {
2846 int msglen;
2847
2848 nlh = nlmsg_hdr(skb);
2849 err = 0;
2850
2851 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2852 return 0;
2853
2854 /* Only requests are handled by the kernel */
2855 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2856 goto ack;
2857
2858 /* Skip control messages */
2859 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2860 goto ack;
2861
2862 err = cb(skb, nlh);
2863 if (err == -EINTR)
2864 goto skip;
2865
2866ack:
2867 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2868 netlink_ack(skb, nlh, err);
2869
2870skip:
2871 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2872 if (msglen > skb->len)
2873 msglen = skb->len;
2874 skb_pull(skb, msglen);
2875 }
2876
2877 return 0;
2878}
2879EXPORT_SYMBOL(netlink_rcv_skb);
2880
2881/**
2882 * nlmsg_notify - send a notification netlink message
2883 * @sk: netlink socket to use
2884 * @skb: notification message
2885 * @portid: destination netlink portid for reports or 0
2886 * @group: destination multicast group or 0
2887 * @report: 1 to report back, 0 to disable
2888 * @flags: allocation flags
2889 */
2890int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2891 unsigned int group, int report, gfp_t flags)
2892{
2893 int err = 0;
2894
2895 if (group) {
2896 int exclude_portid = 0;
2897
2898 if (report) {
2899 atomic_inc(&skb->users);
2900 exclude_portid = portid;
2901 }
2902
2903 /* errors reported via destination sk->sk_err, but propagate
2904 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2905 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2906 }
2907
2908 if (report) {
2909 int err2;
2910
2911 err2 = nlmsg_unicast(sk, skb, portid);
2912 if (!err || err == -ESRCH)
2913 err = err2;
2914 }
2915
2916 return err;
2917}
2918EXPORT_SYMBOL(nlmsg_notify);
2919
2920#ifdef CONFIG_PROC_FS
2921struct nl_seq_iter {
2922 struct seq_net_private p;
2923 int link;
2924 int hash_idx;
2925};
2926
2927static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
2928{
2929 struct nl_seq_iter *iter = seq->private;
2930 int i, j;
2931 struct sock *s;
2932 loff_t off = 0;
2933
2934 for (i = 0; i < MAX_LINKS; i++) {
2935 struct nl_portid_hash *hash = &nl_table[i].hash;
2936
2937 for (j = 0; j <= hash->mask; j++) {
2938 sk_for_each(s, &hash->table[j]) {
2939 if (sock_net(s) != seq_file_net(seq))
2940 continue;
2941 if (off == pos) {
2942 iter->link = i;
2943 iter->hash_idx = j;
2944 return s;
2945 }
2946 ++off;
2947 }
2948 }
2949 }
2950 return NULL;
2951}
2952
2953static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
2954 __acquires(nl_table_lock)
2955{
2956 read_lock(&nl_table_lock);
2957 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2958}
2959
2960static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2961{
2962 struct sock *s;
2963 struct nl_seq_iter *iter;
2964 struct net *net;
2965 int i, j;
2966
2967 ++*pos;
2968
2969 if (v == SEQ_START_TOKEN)
2970 return netlink_seq_socket_idx(seq, 0);
2971
2972 net = seq_file_net(seq);
2973 iter = seq->private;
2974 s = v;
2975 do {
2976 s = sk_next(s);
2977 } while (s && !nl_table[s->sk_protocol].compare(net, s));
2978 if (s)
2979 return s;
2980
2981 i = iter->link;
2982 j = iter->hash_idx + 1;
2983
2984 do {
2985 struct nl_portid_hash *hash = &nl_table[i].hash;
2986
2987 for (; j <= hash->mask; j++) {
2988 s = sk_head(&hash->table[j]);
2989
2990 while (s && !nl_table[s->sk_protocol].compare(net, s))
2991 s = sk_next(s);
2992 if (s) {
2993 iter->link = i;
2994 iter->hash_idx = j;
2995 return s;
2996 }
2997 }
2998
2999 j = 0;
3000 } while (++i < MAX_LINKS);
3001
3002 return NULL;
3003}
3004
3005static void netlink_seq_stop(struct seq_file *seq, void *v)
3006 __releases(nl_table_lock)
3007{
3008 read_unlock(&nl_table_lock);
3009}
3010
3011
3012static int netlink_seq_show(struct seq_file *seq, void *v)
3013{
3014 if (v == SEQ_START_TOKEN) {
3015 seq_puts(seq,
3016 "sk Eth Pid Groups "
3017 "Rmem Wmem Dump Locks Drops Inode\n");
3018 } else {
3019 struct sock *s = v;
3020 struct netlink_sock *nlk = nlk_sk(s);
3021
3022 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
3023 s,
3024 s->sk_protocol,
3025 nlk->portid,
3026 nlk->groups ? (u32)nlk->groups[0] : 0,
3027 sk_rmem_alloc_get(s),
3028 sk_wmem_alloc_get(s),
3029 nlk->cb_running,
3030 atomic_read(&s->sk_refcnt),
3031 atomic_read(&s->sk_drops),
3032 sock_i_ino(s)
3033 );
3034
3035 }
3036 return 0;
3037}
3038
3039static const struct seq_operations netlink_seq_ops = {
3040 .start = netlink_seq_start,
3041 .next = netlink_seq_next,
3042 .stop = netlink_seq_stop,
3043 .show = netlink_seq_show,
3044};
3045
3046
3047static int netlink_seq_open(struct inode *inode, struct file *file)
3048{
3049 return seq_open_net(inode, file, &netlink_seq_ops,
3050 sizeof(struct nl_seq_iter));
3051}
3052
3053static const struct file_operations netlink_seq_fops = {
3054 .owner = THIS_MODULE,
3055 .open = netlink_seq_open,
3056 .read = seq_read,
3057 .llseek = seq_lseek,
3058 .release = seq_release_net,
3059};
3060
3061#endif
3062
3063int netlink_register_notifier(struct notifier_block *nb)
3064{
3065 return atomic_notifier_chain_register(&netlink_chain, nb);
3066}
3067EXPORT_SYMBOL(netlink_register_notifier);
3068
3069int netlink_unregister_notifier(struct notifier_block *nb)
3070{
3071 return atomic_notifier_chain_unregister(&netlink_chain, nb);
3072}
3073EXPORT_SYMBOL(netlink_unregister_notifier);
3074
3075static const struct proto_ops netlink_ops = {
3076 .family = PF_NETLINK,
3077 .owner = THIS_MODULE,
3078 .release = netlink_release,
3079 .bind = netlink_bind,
3080 .connect = netlink_connect,
3081 .socketpair = sock_no_socketpair,
3082 .accept = sock_no_accept,
3083 .getname = netlink_getname,
3084 .poll = netlink_poll,
3085 .ioctl = sock_no_ioctl,
3086 .listen = sock_no_listen,
3087 .shutdown = sock_no_shutdown,
3088 .setsockopt = netlink_setsockopt,
3089 .getsockopt = netlink_getsockopt,
3090 .sendmsg = netlink_sendmsg,
3091 .recvmsg = netlink_recvmsg,
3092 .mmap = netlink_mmap,
3093 .sendpage = sock_no_sendpage,
3094};
3095
3096static const struct net_proto_family netlink_family_ops = {
3097 .family = PF_NETLINK,
3098 .create = netlink_create,
3099 .owner = THIS_MODULE, /* for consistency 8) */
3100};
3101
3102static int __net_init netlink_net_init(struct net *net)
3103{
3104#ifdef CONFIG_PROC_FS
3105 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
3106 return -ENOMEM;
3107#endif
3108 return 0;
3109}
3110
3111static void __net_exit netlink_net_exit(struct net *net)
3112{
3113#ifdef CONFIG_PROC_FS
3114 remove_proc_entry("netlink", net->proc_net);
3115#endif
3116}
3117
3118static void __init netlink_add_usersock_entry(void)
3119{
3120 struct listeners *listeners;
3121 int groups = 32;
3122
3123 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
3124 if (!listeners)
3125 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
3126
3127 netlink_table_grab();
3128
3129 nl_table[NETLINK_USERSOCK].groups = groups;
3130 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
3131 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
3132 nl_table[NETLINK_USERSOCK].registered = 1;
3133 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
3134
3135 netlink_table_ungrab();
3136}
3137
3138static struct pernet_operations __net_initdata netlink_net_ops = {
3139 .init = netlink_net_init,
3140 .exit = netlink_net_exit,
3141};
3142
3143static int __init netlink_proto_init(void)
3144{
3145 int i;
3146 unsigned long limit;
3147 unsigned int order;
3148 int err = proto_register(&netlink_proto, 0);
3149
3150 if (err != 0)
3151 goto out;
3152
3153 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
3154
3155 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
3156 if (!nl_table)
3157 goto panic;
3158
3159 if (totalram_pages >= (128 * 1024))
3160 limit = totalram_pages >> (21 - PAGE_SHIFT);
3161 else
3162 limit = totalram_pages >> (23 - PAGE_SHIFT);
3163
3164 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
3165 limit = (1UL << order) / sizeof(struct hlist_head);
3166 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
3167
3168 for (i = 0; i < MAX_LINKS; i++) {
3169 struct nl_portid_hash *hash = &nl_table[i].hash;
3170
3171 hash->table = nl_portid_hash_zalloc(1 * sizeof(*hash->table));
3172 if (!hash->table) {
3173 while (i-- > 0)
3174 nl_portid_hash_free(nl_table[i].hash.table,
3175 1 * sizeof(*hash->table));
3176 kfree(nl_table);
3177 goto panic;
3178 }
3179 hash->max_shift = order;
3180 hash->shift = 0;
3181 hash->mask = 0;
3182 hash->rehash_time = jiffies;
3183
3184 nl_table[i].compare = netlink_compare;
3185 }
3186
3187 INIT_LIST_HEAD(&netlink_tap_all);
3188
3189 netlink_add_usersock_entry();
3190
3191 sock_register(&netlink_family_ops);
3192 register_pernet_subsys(&netlink_net_ops);
3193 /* The netlink device handler may be needed early. */
3194 rtnetlink_init();
3195out:
3196 return err;
3197panic:
3198 panic("netlink_init: Cannot allocate nl_table\n");
3199}
3200
3201core_initcall(netlink_proto_init);