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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/capability.h>
24#include <linux/kernel.h>
25#include <linux/init.h>
26#include <linux/signal.h>
27#include <linux/sched.h>
28#include <linux/errno.h>
29#include <linux/string.h>
30#include <linux/stat.h>
31#include <linux/socket.h>
32#include <linux/un.h>
33#include <linux/fcntl.h>
34#include <linux/termios.h>
35#include <linux/sockios.h>
36#include <linux/net.h>
37#include <linux/fs.h>
38#include <linux/slab.h>
39#include <linux/uaccess.h>
40#include <linux/skbuff.h>
41#include <linux/netdevice.h>
42#include <linux/rtnetlink.h>
43#include <linux/proc_fs.h>
44#include <linux/seq_file.h>
45#include <linux/notifier.h>
46#include <linux/security.h>
47#include <linux/jhash.h>
48#include <linux/jiffies.h>
49#include <linux/random.h>
50#include <linux/bitops.h>
51#include <linux/mm.h>
52#include <linux/types.h>
53#include <linux/audit.h>
54#include <linux/mutex.h>
55#include <linux/vmalloc.h>
56#include <linux/if_arp.h>
57#include <linux/rhashtable.h>
58#include <asm/cacheflush.h>
59#include <linux/hash.h>
60#include <linux/genetlink.h>
61#include <linux/net_namespace.h>
62#include <linux/nospec.h>
63#include <linux/btf_ids.h>
64
65#include <net/net_namespace.h>
66#include <net/netns/generic.h>
67#include <net/sock.h>
68#include <net/scm.h>
69#include <net/netlink.h>
70#define CREATE_TRACE_POINTS
71#include <trace/events/netlink.h>
72
73#include "af_netlink.h"
74
75struct listeners {
76 struct rcu_head rcu;
77 unsigned long masks[];
78};
79
80/* state bits */
81#define NETLINK_S_CONGESTED 0x0
82
83static inline int netlink_is_kernel(struct sock *sk)
84{
85 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;
86}
87
88struct netlink_table *nl_table __read_mostly;
89EXPORT_SYMBOL_GPL(nl_table);
90
91static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
92
93static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
94
95static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
96 "nlk_cb_mutex-ROUTE",
97 "nlk_cb_mutex-1",
98 "nlk_cb_mutex-USERSOCK",
99 "nlk_cb_mutex-FIREWALL",
100 "nlk_cb_mutex-SOCK_DIAG",
101 "nlk_cb_mutex-NFLOG",
102 "nlk_cb_mutex-XFRM",
103 "nlk_cb_mutex-SELINUX",
104 "nlk_cb_mutex-ISCSI",
105 "nlk_cb_mutex-AUDIT",
106 "nlk_cb_mutex-FIB_LOOKUP",
107 "nlk_cb_mutex-CONNECTOR",
108 "nlk_cb_mutex-NETFILTER",
109 "nlk_cb_mutex-IP6_FW",
110 "nlk_cb_mutex-DNRTMSG",
111 "nlk_cb_mutex-KOBJECT_UEVENT",
112 "nlk_cb_mutex-GENERIC",
113 "nlk_cb_mutex-17",
114 "nlk_cb_mutex-SCSITRANSPORT",
115 "nlk_cb_mutex-ECRYPTFS",
116 "nlk_cb_mutex-RDMA",
117 "nlk_cb_mutex-CRYPTO",
118 "nlk_cb_mutex-SMC",
119 "nlk_cb_mutex-23",
120 "nlk_cb_mutex-24",
121 "nlk_cb_mutex-25",
122 "nlk_cb_mutex-26",
123 "nlk_cb_mutex-27",
124 "nlk_cb_mutex-28",
125 "nlk_cb_mutex-29",
126 "nlk_cb_mutex-30",
127 "nlk_cb_mutex-31",
128 "nlk_cb_mutex-MAX_LINKS"
129};
130
131static int netlink_dump(struct sock *sk);
132
133/* nl_table locking explained:
134 * Lookup and traversal are protected with an RCU read-side lock. Insertion
135 * and removal are protected with per bucket lock while using RCU list
136 * modification primitives and may run in parallel to RCU protected lookups.
137 * Destruction of the Netlink socket may only occur *after* nl_table_lock has
138 * been acquired * either during or after the socket has been removed from
139 * the list and after an RCU grace period.
140 */
141DEFINE_RWLOCK(nl_table_lock);
142EXPORT_SYMBOL_GPL(nl_table_lock);
143static atomic_t nl_table_users = ATOMIC_INIT(0);
144
145#define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
146
147static BLOCKING_NOTIFIER_HEAD(netlink_chain);
148
149
150static const struct rhashtable_params netlink_rhashtable_params;
151
152void do_trace_netlink_extack(const char *msg)
153{
154 trace_netlink_extack(msg);
155}
156EXPORT_SYMBOL(do_trace_netlink_extack);
157
158static inline u32 netlink_group_mask(u32 group)
159{
160 return group ? 1 << (group - 1) : 0;
161}
162
163static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
164 gfp_t gfp_mask)
165{
166 unsigned int len = skb_end_offset(skb);
167 struct sk_buff *new;
168
169 new = alloc_skb(len, gfp_mask);
170 if (new == NULL)
171 return NULL;
172
173 NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
174 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
175 NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
176
177 skb_put_data(new, skb->data, len);
178 return new;
179}
180
181static unsigned int netlink_tap_net_id;
182
183struct netlink_tap_net {
184 struct list_head netlink_tap_all;
185 struct mutex netlink_tap_lock;
186};
187
188int netlink_add_tap(struct netlink_tap *nt)
189{
190 struct net *net = dev_net(nt->dev);
191 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
192
193 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
194 return -EINVAL;
195
196 mutex_lock(&nn->netlink_tap_lock);
197 list_add_rcu(&nt->list, &nn->netlink_tap_all);
198 mutex_unlock(&nn->netlink_tap_lock);
199
200 __module_get(nt->module);
201
202 return 0;
203}
204EXPORT_SYMBOL_GPL(netlink_add_tap);
205
206static int __netlink_remove_tap(struct netlink_tap *nt)
207{
208 struct net *net = dev_net(nt->dev);
209 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
210 bool found = false;
211 struct netlink_tap *tmp;
212
213 mutex_lock(&nn->netlink_tap_lock);
214
215 list_for_each_entry(tmp, &nn->netlink_tap_all, list) {
216 if (nt == tmp) {
217 list_del_rcu(&nt->list);
218 found = true;
219 goto out;
220 }
221 }
222
223 pr_warn("__netlink_remove_tap: %p not found\n", nt);
224out:
225 mutex_unlock(&nn->netlink_tap_lock);
226
227 if (found)
228 module_put(nt->module);
229
230 return found ? 0 : -ENODEV;
231}
232
233int netlink_remove_tap(struct netlink_tap *nt)
234{
235 int ret;
236
237 ret = __netlink_remove_tap(nt);
238 synchronize_net();
239
240 return ret;
241}
242EXPORT_SYMBOL_GPL(netlink_remove_tap);
243
244static __net_init int netlink_tap_init_net(struct net *net)
245{
246 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
247
248 INIT_LIST_HEAD(&nn->netlink_tap_all);
249 mutex_init(&nn->netlink_tap_lock);
250 return 0;
251}
252
253static struct pernet_operations netlink_tap_net_ops = {
254 .init = netlink_tap_init_net,
255 .id = &netlink_tap_net_id,
256 .size = sizeof(struct netlink_tap_net),
257};
258
259static bool netlink_filter_tap(const struct sk_buff *skb)
260{
261 struct sock *sk = skb->sk;
262
263 /* We take the more conservative approach and
264 * whitelist socket protocols that may pass.
265 */
266 switch (sk->sk_protocol) {
267 case NETLINK_ROUTE:
268 case NETLINK_USERSOCK:
269 case NETLINK_SOCK_DIAG:
270 case NETLINK_NFLOG:
271 case NETLINK_XFRM:
272 case NETLINK_FIB_LOOKUP:
273 case NETLINK_NETFILTER:
274 case NETLINK_GENERIC:
275 return true;
276 }
277
278 return false;
279}
280
281static int __netlink_deliver_tap_skb(struct sk_buff *skb,
282 struct net_device *dev)
283{
284 struct sk_buff *nskb;
285 struct sock *sk = skb->sk;
286 int ret = -ENOMEM;
287
288 if (!net_eq(dev_net(dev), sock_net(sk)))
289 return 0;
290
291 dev_hold(dev);
292
293 if (is_vmalloc_addr(skb->head))
294 nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
295 else
296 nskb = skb_clone(skb, GFP_ATOMIC);
297 if (nskb) {
298 nskb->dev = dev;
299 nskb->protocol = htons((u16) sk->sk_protocol);
300 nskb->pkt_type = netlink_is_kernel(sk) ?
301 PACKET_KERNEL : PACKET_USER;
302 skb_reset_network_header(nskb);
303 ret = dev_queue_xmit(nskb);
304 if (unlikely(ret > 0))
305 ret = net_xmit_errno(ret);
306 }
307
308 dev_put(dev);
309 return ret;
310}
311
312static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn)
313{
314 int ret;
315 struct netlink_tap *tmp;
316
317 if (!netlink_filter_tap(skb))
318 return;
319
320 list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) {
321 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
322 if (unlikely(ret))
323 break;
324 }
325}
326
327static void netlink_deliver_tap(struct net *net, struct sk_buff *skb)
328{
329 struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
330
331 rcu_read_lock();
332
333 if (unlikely(!list_empty(&nn->netlink_tap_all)))
334 __netlink_deliver_tap(skb, nn);
335
336 rcu_read_unlock();
337}
338
339static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
340 struct sk_buff *skb)
341{
342 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
343 netlink_deliver_tap(sock_net(dst), skb);
344}
345
346static void netlink_overrun(struct sock *sk)
347{
348 struct netlink_sock *nlk = nlk_sk(sk);
349
350 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
351 if (!test_and_set_bit(NETLINK_S_CONGESTED,
352 &nlk_sk(sk)->state)) {
353 sk->sk_err = ENOBUFS;
354 sk_error_report(sk);
355 }
356 }
357 atomic_inc(&sk->sk_drops);
358}
359
360static void netlink_rcv_wake(struct sock *sk)
361{
362 struct netlink_sock *nlk = nlk_sk(sk);
363
364 if (skb_queue_empty_lockless(&sk->sk_receive_queue))
365 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
366 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
367 wake_up_interruptible(&nlk->wait);
368}
369
370static void netlink_skb_destructor(struct sk_buff *skb)
371{
372 if (is_vmalloc_addr(skb->head)) {
373 if (!skb->cloned ||
374 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
375 vfree(skb->head);
376
377 skb->head = NULL;
378 }
379 if (skb->sk != NULL)
380 sock_rfree(skb);
381}
382
383static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
384{
385 WARN_ON(skb->sk != NULL);
386 skb->sk = sk;
387 skb->destructor = netlink_skb_destructor;
388 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
389 sk_mem_charge(sk, skb->truesize);
390}
391
392static void netlink_sock_destruct(struct sock *sk)
393{
394 struct netlink_sock *nlk = nlk_sk(sk);
395
396 if (nlk->cb_running) {
397 if (nlk->cb.done)
398 nlk->cb.done(&nlk->cb);
399 module_put(nlk->cb.module);
400 kfree_skb(nlk->cb.skb);
401 }
402
403 skb_queue_purge(&sk->sk_receive_queue);
404
405 if (!sock_flag(sk, SOCK_DEAD)) {
406 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
407 return;
408 }
409
410 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
411 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
412 WARN_ON(nlk_sk(sk)->groups);
413}
414
415static void netlink_sock_destruct_work(struct work_struct *work)
416{
417 struct netlink_sock *nlk = container_of(work, struct netlink_sock,
418 work);
419
420 sk_free(&nlk->sk);
421}
422
423/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
424 * SMP. Look, when several writers sleep and reader wakes them up, all but one
425 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
426 * this, _but_ remember, it adds useless work on UP machines.
427 */
428
429void netlink_table_grab(void)
430 __acquires(nl_table_lock)
431{
432 might_sleep();
433
434 write_lock_irq(&nl_table_lock);
435
436 if (atomic_read(&nl_table_users)) {
437 DECLARE_WAITQUEUE(wait, current);
438
439 add_wait_queue_exclusive(&nl_table_wait, &wait);
440 for (;;) {
441 set_current_state(TASK_UNINTERRUPTIBLE);
442 if (atomic_read(&nl_table_users) == 0)
443 break;
444 write_unlock_irq(&nl_table_lock);
445 schedule();
446 write_lock_irq(&nl_table_lock);
447 }
448
449 __set_current_state(TASK_RUNNING);
450 remove_wait_queue(&nl_table_wait, &wait);
451 }
452}
453
454void netlink_table_ungrab(void)
455 __releases(nl_table_lock)
456{
457 write_unlock_irq(&nl_table_lock);
458 wake_up(&nl_table_wait);
459}
460
461static inline void
462netlink_lock_table(void)
463{
464 unsigned long flags;
465
466 /* read_lock() synchronizes us to netlink_table_grab */
467
468 read_lock_irqsave(&nl_table_lock, flags);
469 atomic_inc(&nl_table_users);
470 read_unlock_irqrestore(&nl_table_lock, flags);
471}
472
473static inline void
474netlink_unlock_table(void)
475{
476 if (atomic_dec_and_test(&nl_table_users))
477 wake_up(&nl_table_wait);
478}
479
480struct netlink_compare_arg
481{
482 possible_net_t pnet;
483 u32 portid;
484};
485
486/* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
487#define netlink_compare_arg_len \
488 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
489
490static inline int netlink_compare(struct rhashtable_compare_arg *arg,
491 const void *ptr)
492{
493 const struct netlink_compare_arg *x = arg->key;
494 const struct netlink_sock *nlk = ptr;
495
496 return nlk->portid != x->portid ||
497 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
498}
499
500static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
501 struct net *net, u32 portid)
502{
503 memset(arg, 0, sizeof(*arg));
504 write_pnet(&arg->pnet, net);
505 arg->portid = portid;
506}
507
508static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
509 struct net *net)
510{
511 struct netlink_compare_arg arg;
512
513 netlink_compare_arg_init(&arg, net, portid);
514 return rhashtable_lookup_fast(&table->hash, &arg,
515 netlink_rhashtable_params);
516}
517
518static int __netlink_insert(struct netlink_table *table, struct sock *sk)
519{
520 struct netlink_compare_arg arg;
521
522 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
523 return rhashtable_lookup_insert_key(&table->hash, &arg,
524 &nlk_sk(sk)->node,
525 netlink_rhashtable_params);
526}
527
528static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
529{
530 struct netlink_table *table = &nl_table[protocol];
531 struct sock *sk;
532
533 rcu_read_lock();
534 sk = __netlink_lookup(table, portid, net);
535 if (sk)
536 sock_hold(sk);
537 rcu_read_unlock();
538
539 return sk;
540}
541
542static const struct proto_ops netlink_ops;
543
544static void
545netlink_update_listeners(struct sock *sk)
546{
547 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
548 unsigned long mask;
549 unsigned int i;
550 struct listeners *listeners;
551
552 listeners = nl_deref_protected(tbl->listeners);
553 if (!listeners)
554 return;
555
556 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
557 mask = 0;
558 sk_for_each_bound(sk, &tbl->mc_list) {
559 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
560 mask |= nlk_sk(sk)->groups[i];
561 }
562 listeners->masks[i] = mask;
563 }
564 /* this function is only called with the netlink table "grabbed", which
565 * makes sure updates are visible before bind or setsockopt return. */
566}
567
568static int netlink_insert(struct sock *sk, u32 portid)
569{
570 struct netlink_table *table = &nl_table[sk->sk_protocol];
571 int err;
572
573 lock_sock(sk);
574
575 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
576 if (nlk_sk(sk)->bound)
577 goto err;
578
579 nlk_sk(sk)->portid = portid;
580 sock_hold(sk);
581
582 err = __netlink_insert(table, sk);
583 if (err) {
584 /* In case the hashtable backend returns with -EBUSY
585 * from here, it must not escape to the caller.
586 */
587 if (unlikely(err == -EBUSY))
588 err = -EOVERFLOW;
589 if (err == -EEXIST)
590 err = -EADDRINUSE;
591 sock_put(sk);
592 goto err;
593 }
594
595 /* We need to ensure that the socket is hashed and visible. */
596 smp_wmb();
597 /* Paired with lockless reads from netlink_bind(),
598 * netlink_connect() and netlink_sendmsg().
599 */
600 WRITE_ONCE(nlk_sk(sk)->bound, portid);
601
602err:
603 release_sock(sk);
604 return err;
605}
606
607static void netlink_remove(struct sock *sk)
608{
609 struct netlink_table *table;
610
611 table = &nl_table[sk->sk_protocol];
612 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
613 netlink_rhashtable_params)) {
614 WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
615 __sock_put(sk);
616 }
617
618 netlink_table_grab();
619 if (nlk_sk(sk)->subscriptions) {
620 __sk_del_bind_node(sk);
621 netlink_update_listeners(sk);
622 }
623 if (sk->sk_protocol == NETLINK_GENERIC)
624 atomic_inc(&genl_sk_destructing_cnt);
625 netlink_table_ungrab();
626}
627
628static struct proto netlink_proto = {
629 .name = "NETLINK",
630 .owner = THIS_MODULE,
631 .obj_size = sizeof(struct netlink_sock),
632};
633
634static int __netlink_create(struct net *net, struct socket *sock,
635 struct mutex *cb_mutex, int protocol,
636 int kern)
637{
638 struct sock *sk;
639 struct netlink_sock *nlk;
640
641 sock->ops = &netlink_ops;
642
643 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
644 if (!sk)
645 return -ENOMEM;
646
647 sock_init_data(sock, sk);
648
649 nlk = nlk_sk(sk);
650 if (cb_mutex) {
651 nlk->cb_mutex = cb_mutex;
652 } else {
653 nlk->cb_mutex = &nlk->cb_def_mutex;
654 mutex_init(nlk->cb_mutex);
655 lockdep_set_class_and_name(nlk->cb_mutex,
656 nlk_cb_mutex_keys + protocol,
657 nlk_cb_mutex_key_strings[protocol]);
658 }
659 init_waitqueue_head(&nlk->wait);
660
661 sk->sk_destruct = netlink_sock_destruct;
662 sk->sk_protocol = protocol;
663 return 0;
664}
665
666static int netlink_create(struct net *net, struct socket *sock, int protocol,
667 int kern)
668{
669 struct module *module = NULL;
670 struct mutex *cb_mutex;
671 struct netlink_sock *nlk;
672 int (*bind)(struct net *net, int group);
673 void (*unbind)(struct net *net, int group);
674 int err = 0;
675
676 sock->state = SS_UNCONNECTED;
677
678 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
679 return -ESOCKTNOSUPPORT;
680
681 if (protocol < 0 || protocol >= MAX_LINKS)
682 return -EPROTONOSUPPORT;
683 protocol = array_index_nospec(protocol, MAX_LINKS);
684
685 netlink_lock_table();
686#ifdef CONFIG_MODULES
687 if (!nl_table[protocol].registered) {
688 netlink_unlock_table();
689 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
690 netlink_lock_table();
691 }
692#endif
693 if (nl_table[protocol].registered &&
694 try_module_get(nl_table[protocol].module))
695 module = nl_table[protocol].module;
696 else
697 err = -EPROTONOSUPPORT;
698 cb_mutex = nl_table[protocol].cb_mutex;
699 bind = nl_table[protocol].bind;
700 unbind = nl_table[protocol].unbind;
701 netlink_unlock_table();
702
703 if (err < 0)
704 goto out;
705
706 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
707 if (err < 0)
708 goto out_module;
709
710 local_bh_disable();
711 sock_prot_inuse_add(net, &netlink_proto, 1);
712 local_bh_enable();
713
714 nlk = nlk_sk(sock->sk);
715 nlk->module = module;
716 nlk->netlink_bind = bind;
717 nlk->netlink_unbind = unbind;
718out:
719 return err;
720
721out_module:
722 module_put(module);
723 goto out;
724}
725
726static void deferred_put_nlk_sk(struct rcu_head *head)
727{
728 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
729 struct sock *sk = &nlk->sk;
730
731 kfree(nlk->groups);
732 nlk->groups = NULL;
733
734 if (!refcount_dec_and_test(&sk->sk_refcnt))
735 return;
736
737 if (nlk->cb_running && nlk->cb.done) {
738 INIT_WORK(&nlk->work, netlink_sock_destruct_work);
739 schedule_work(&nlk->work);
740 return;
741 }
742
743 sk_free(sk);
744}
745
746static int netlink_release(struct socket *sock)
747{
748 struct sock *sk = sock->sk;
749 struct netlink_sock *nlk;
750
751 if (!sk)
752 return 0;
753
754 netlink_remove(sk);
755 sock_orphan(sk);
756 nlk = nlk_sk(sk);
757
758 /*
759 * OK. Socket is unlinked, any packets that arrive now
760 * will be purged.
761 */
762
763 /* must not acquire netlink_table_lock in any way again before unbind
764 * and notifying genetlink is done as otherwise it might deadlock
765 */
766 if (nlk->netlink_unbind) {
767 int i;
768
769 for (i = 0; i < nlk->ngroups; i++)
770 if (test_bit(i, nlk->groups))
771 nlk->netlink_unbind(sock_net(sk), i + 1);
772 }
773 if (sk->sk_protocol == NETLINK_GENERIC &&
774 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
775 wake_up(&genl_sk_destructing_waitq);
776
777 sock->sk = NULL;
778 wake_up_interruptible_all(&nlk->wait);
779
780 skb_queue_purge(&sk->sk_write_queue);
781
782 if (nlk->portid && nlk->bound) {
783 struct netlink_notify n = {
784 .net = sock_net(sk),
785 .protocol = sk->sk_protocol,
786 .portid = nlk->portid,
787 };
788 blocking_notifier_call_chain(&netlink_chain,
789 NETLINK_URELEASE, &n);
790 }
791
792 module_put(nlk->module);
793
794 if (netlink_is_kernel(sk)) {
795 netlink_table_grab();
796 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
797 if (--nl_table[sk->sk_protocol].registered == 0) {
798 struct listeners *old;
799
800 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
801 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
802 kfree_rcu(old, rcu);
803 nl_table[sk->sk_protocol].module = NULL;
804 nl_table[sk->sk_protocol].bind = NULL;
805 nl_table[sk->sk_protocol].unbind = NULL;
806 nl_table[sk->sk_protocol].flags = 0;
807 nl_table[sk->sk_protocol].registered = 0;
808 }
809 netlink_table_ungrab();
810 }
811
812 local_bh_disable();
813 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
814 local_bh_enable();
815 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
816 return 0;
817}
818
819static int netlink_autobind(struct socket *sock)
820{
821 struct sock *sk = sock->sk;
822 struct net *net = sock_net(sk);
823 struct netlink_table *table = &nl_table[sk->sk_protocol];
824 s32 portid = task_tgid_vnr(current);
825 int err;
826 s32 rover = -4096;
827 bool ok;
828
829retry:
830 cond_resched();
831 rcu_read_lock();
832 ok = !__netlink_lookup(table, portid, net);
833 rcu_read_unlock();
834 if (!ok) {
835 /* Bind collision, search negative portid values. */
836 if (rover == -4096)
837 /* rover will be in range [S32_MIN, -4097] */
838 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
839 else if (rover >= -4096)
840 rover = -4097;
841 portid = rover--;
842 goto retry;
843 }
844
845 err = netlink_insert(sk, portid);
846 if (err == -EADDRINUSE)
847 goto retry;
848
849 /* If 2 threads race to autobind, that is fine. */
850 if (err == -EBUSY)
851 err = 0;
852
853 return err;
854}
855
856/**
857 * __netlink_ns_capable - General netlink message capability test
858 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
859 * @user_ns: The user namespace of the capability to use
860 * @cap: The capability to use
861 *
862 * Test to see if the opener of the socket we received the message
863 * from had when the netlink socket was created and the sender of the
864 * message has the capability @cap in the user namespace @user_ns.
865 */
866bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
867 struct user_namespace *user_ns, int cap)
868{
869 return ((nsp->flags & NETLINK_SKB_DST) ||
870 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
871 ns_capable(user_ns, cap);
872}
873EXPORT_SYMBOL(__netlink_ns_capable);
874
875/**
876 * netlink_ns_capable - General netlink message capability test
877 * @skb: socket buffer holding a netlink command from userspace
878 * @user_ns: The user namespace of the capability to use
879 * @cap: The capability to use
880 *
881 * Test to see if the opener of the socket we received the message
882 * from had when the netlink socket was created and the sender of the
883 * message has the capability @cap in the user namespace @user_ns.
884 */
885bool netlink_ns_capable(const struct sk_buff *skb,
886 struct user_namespace *user_ns, int cap)
887{
888 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
889}
890EXPORT_SYMBOL(netlink_ns_capable);
891
892/**
893 * netlink_capable - Netlink global message capability test
894 * @skb: socket buffer holding a netlink command from userspace
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 all user namespaces.
900 */
901bool netlink_capable(const struct sk_buff *skb, int cap)
902{
903 return netlink_ns_capable(skb, &init_user_ns, cap);
904}
905EXPORT_SYMBOL(netlink_capable);
906
907/**
908 * netlink_net_capable - Netlink network namespace message capability test
909 * @skb: socket buffer holding a netlink command from userspace
910 * @cap: The capability to use
911 *
912 * Test to see if the opener of the socket we received the message
913 * from had when the netlink socket was created and the sender of the
914 * message has the capability @cap over the network namespace of
915 * the socket we received the message from.
916 */
917bool netlink_net_capable(const struct sk_buff *skb, int cap)
918{
919 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
920}
921EXPORT_SYMBOL(netlink_net_capable);
922
923static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
924{
925 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
926 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
927}
928
929static void
930netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
931{
932 struct netlink_sock *nlk = nlk_sk(sk);
933
934 if (nlk->subscriptions && !subscriptions)
935 __sk_del_bind_node(sk);
936 else if (!nlk->subscriptions && subscriptions)
937 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
938 nlk->subscriptions = subscriptions;
939}
940
941static int netlink_realloc_groups(struct sock *sk)
942{
943 struct netlink_sock *nlk = nlk_sk(sk);
944 unsigned int groups;
945 unsigned long *new_groups;
946 int err = 0;
947
948 netlink_table_grab();
949
950 groups = nl_table[sk->sk_protocol].groups;
951 if (!nl_table[sk->sk_protocol].registered) {
952 err = -ENOENT;
953 goto out_unlock;
954 }
955
956 if (nlk->ngroups >= groups)
957 goto out_unlock;
958
959 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
960 if (new_groups == NULL) {
961 err = -ENOMEM;
962 goto out_unlock;
963 }
964 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
965 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
966
967 nlk->groups = new_groups;
968 nlk->ngroups = groups;
969 out_unlock:
970 netlink_table_ungrab();
971 return err;
972}
973
974static void netlink_undo_bind(int group, long unsigned int groups,
975 struct sock *sk)
976{
977 struct netlink_sock *nlk = nlk_sk(sk);
978 int undo;
979
980 if (!nlk->netlink_unbind)
981 return;
982
983 for (undo = 0; undo < group; undo++)
984 if (test_bit(undo, &groups))
985 nlk->netlink_unbind(sock_net(sk), undo + 1);
986}
987
988static int netlink_bind(struct socket *sock, struct sockaddr *addr,
989 int addr_len)
990{
991 struct sock *sk = sock->sk;
992 struct net *net = sock_net(sk);
993 struct netlink_sock *nlk = nlk_sk(sk);
994 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
995 int err = 0;
996 unsigned long groups;
997 bool bound;
998
999 if (addr_len < sizeof(struct sockaddr_nl))
1000 return -EINVAL;
1001
1002 if (nladdr->nl_family != AF_NETLINK)
1003 return -EINVAL;
1004 groups = nladdr->nl_groups;
1005
1006 /* Only superuser is allowed to listen multicasts */
1007 if (groups) {
1008 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1009 return -EPERM;
1010 err = netlink_realloc_groups(sk);
1011 if (err)
1012 return err;
1013 }
1014
1015 if (nlk->ngroups < BITS_PER_LONG)
1016 groups &= (1UL << nlk->ngroups) - 1;
1017
1018 /* Paired with WRITE_ONCE() in netlink_insert() */
1019 bound = READ_ONCE(nlk->bound);
1020 if (bound) {
1021 /* Ensure nlk->portid is up-to-date. */
1022 smp_rmb();
1023
1024 if (nladdr->nl_pid != nlk->portid)
1025 return -EINVAL;
1026 }
1027
1028 if (nlk->netlink_bind && groups) {
1029 int group;
1030
1031 /* nl_groups is a u32, so cap the maximum groups we can bind */
1032 for (group = 0; group < BITS_PER_TYPE(u32); group++) {
1033 if (!test_bit(group, &groups))
1034 continue;
1035 err = nlk->netlink_bind(net, group + 1);
1036 if (!err)
1037 continue;
1038 netlink_undo_bind(group, groups, sk);
1039 return err;
1040 }
1041 }
1042
1043 /* No need for barriers here as we return to user-space without
1044 * using any of the bound attributes.
1045 */
1046 netlink_lock_table();
1047 if (!bound) {
1048 err = nladdr->nl_pid ?
1049 netlink_insert(sk, nladdr->nl_pid) :
1050 netlink_autobind(sock);
1051 if (err) {
1052 netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk);
1053 goto unlock;
1054 }
1055 }
1056
1057 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1058 goto unlock;
1059 netlink_unlock_table();
1060
1061 netlink_table_grab();
1062 netlink_update_subscriptions(sk, nlk->subscriptions +
1063 hweight32(groups) -
1064 hweight32(nlk->groups[0]));
1065 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1066 netlink_update_listeners(sk);
1067 netlink_table_ungrab();
1068
1069 return 0;
1070
1071unlock:
1072 netlink_unlock_table();
1073 return err;
1074}
1075
1076static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1077 int alen, int flags)
1078{
1079 int err = 0;
1080 struct sock *sk = sock->sk;
1081 struct netlink_sock *nlk = nlk_sk(sk);
1082 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1083
1084 if (alen < sizeof(addr->sa_family))
1085 return -EINVAL;
1086
1087 if (addr->sa_family == AF_UNSPEC) {
1088 sk->sk_state = NETLINK_UNCONNECTED;
1089 nlk->dst_portid = 0;
1090 nlk->dst_group = 0;
1091 return 0;
1092 }
1093 if (addr->sa_family != AF_NETLINK)
1094 return -EINVAL;
1095
1096 if (alen < sizeof(struct sockaddr_nl))
1097 return -EINVAL;
1098
1099 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1100 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1101 return -EPERM;
1102
1103 /* No need for barriers here as we return to user-space without
1104 * using any of the bound attributes.
1105 * Paired with WRITE_ONCE() in netlink_insert().
1106 */
1107 if (!READ_ONCE(nlk->bound))
1108 err = netlink_autobind(sock);
1109
1110 if (err == 0) {
1111 sk->sk_state = NETLINK_CONNECTED;
1112 nlk->dst_portid = nladdr->nl_pid;
1113 nlk->dst_group = ffs(nladdr->nl_groups);
1114 }
1115
1116 return err;
1117}
1118
1119static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1120 int peer)
1121{
1122 struct sock *sk = sock->sk;
1123 struct netlink_sock *nlk = nlk_sk(sk);
1124 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1125
1126 nladdr->nl_family = AF_NETLINK;
1127 nladdr->nl_pad = 0;
1128
1129 if (peer) {
1130 nladdr->nl_pid = nlk->dst_portid;
1131 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1132 } else {
1133 nladdr->nl_pid = nlk->portid;
1134 netlink_lock_table();
1135 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1136 netlink_unlock_table();
1137 }
1138 return sizeof(*nladdr);
1139}
1140
1141static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1142 unsigned long arg)
1143{
1144 /* try to hand this ioctl down to the NIC drivers.
1145 */
1146 return -ENOIOCTLCMD;
1147}
1148
1149static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1150{
1151 struct sock *sock;
1152 struct netlink_sock *nlk;
1153
1154 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1155 if (!sock)
1156 return ERR_PTR(-ECONNREFUSED);
1157
1158 /* Don't bother queuing skb if kernel socket has no input function */
1159 nlk = nlk_sk(sock);
1160 if (sock->sk_state == NETLINK_CONNECTED &&
1161 nlk->dst_portid != nlk_sk(ssk)->portid) {
1162 sock_put(sock);
1163 return ERR_PTR(-ECONNREFUSED);
1164 }
1165 return sock;
1166}
1167
1168struct sock *netlink_getsockbyfilp(struct file *filp)
1169{
1170 struct inode *inode = file_inode(filp);
1171 struct sock *sock;
1172
1173 if (!S_ISSOCK(inode->i_mode))
1174 return ERR_PTR(-ENOTSOCK);
1175
1176 sock = SOCKET_I(inode)->sk;
1177 if (sock->sk_family != AF_NETLINK)
1178 return ERR_PTR(-EINVAL);
1179
1180 sock_hold(sock);
1181 return sock;
1182}
1183
1184static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1185 int broadcast)
1186{
1187 struct sk_buff *skb;
1188 void *data;
1189
1190 if (size <= NLMSG_GOODSIZE || broadcast)
1191 return alloc_skb(size, GFP_KERNEL);
1192
1193 size = SKB_DATA_ALIGN(size) +
1194 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1195
1196 data = vmalloc(size);
1197 if (data == NULL)
1198 return NULL;
1199
1200 skb = __build_skb(data, size);
1201 if (skb == NULL)
1202 vfree(data);
1203 else
1204 skb->destructor = netlink_skb_destructor;
1205
1206 return skb;
1207}
1208
1209/*
1210 * Attach a skb to a netlink socket.
1211 * The caller must hold a reference to the destination socket. On error, the
1212 * reference is dropped. The skb is not send to the destination, just all
1213 * all error checks are performed and memory in the queue is reserved.
1214 * Return values:
1215 * < 0: error. skb freed, reference to sock dropped.
1216 * 0: continue
1217 * 1: repeat lookup - reference dropped while waiting for socket memory.
1218 */
1219int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1220 long *timeo, struct sock *ssk)
1221{
1222 struct netlink_sock *nlk;
1223
1224 nlk = nlk_sk(sk);
1225
1226 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1227 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1228 DECLARE_WAITQUEUE(wait, current);
1229 if (!*timeo) {
1230 if (!ssk || netlink_is_kernel(ssk))
1231 netlink_overrun(sk);
1232 sock_put(sk);
1233 kfree_skb(skb);
1234 return -EAGAIN;
1235 }
1236
1237 __set_current_state(TASK_INTERRUPTIBLE);
1238 add_wait_queue(&nlk->wait, &wait);
1239
1240 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1241 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1242 !sock_flag(sk, SOCK_DEAD))
1243 *timeo = schedule_timeout(*timeo);
1244
1245 __set_current_state(TASK_RUNNING);
1246 remove_wait_queue(&nlk->wait, &wait);
1247 sock_put(sk);
1248
1249 if (signal_pending(current)) {
1250 kfree_skb(skb);
1251 return sock_intr_errno(*timeo);
1252 }
1253 return 1;
1254 }
1255 netlink_skb_set_owner_r(skb, sk);
1256 return 0;
1257}
1258
1259static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1260{
1261 int len = skb->len;
1262
1263 netlink_deliver_tap(sock_net(sk), skb);
1264
1265 skb_queue_tail(&sk->sk_receive_queue, skb);
1266 sk->sk_data_ready(sk);
1267 return len;
1268}
1269
1270int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1271{
1272 int len = __netlink_sendskb(sk, skb);
1273
1274 sock_put(sk);
1275 return len;
1276}
1277
1278void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1279{
1280 kfree_skb(skb);
1281 sock_put(sk);
1282}
1283
1284static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1285{
1286 int delta;
1287
1288 WARN_ON(skb->sk != NULL);
1289 delta = skb->end - skb->tail;
1290 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1291 return skb;
1292
1293 if (skb_shared(skb)) {
1294 struct sk_buff *nskb = skb_clone(skb, allocation);
1295 if (!nskb)
1296 return skb;
1297 consume_skb(skb);
1298 skb = nskb;
1299 }
1300
1301 pskb_expand_head(skb, 0, -delta,
1302 (allocation & ~__GFP_DIRECT_RECLAIM) |
1303 __GFP_NOWARN | __GFP_NORETRY);
1304 return skb;
1305}
1306
1307static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1308 struct sock *ssk)
1309{
1310 int ret;
1311 struct netlink_sock *nlk = nlk_sk(sk);
1312
1313 ret = -ECONNREFUSED;
1314 if (nlk->netlink_rcv != NULL) {
1315 ret = skb->len;
1316 netlink_skb_set_owner_r(skb, sk);
1317 NETLINK_CB(skb).sk = ssk;
1318 netlink_deliver_tap_kernel(sk, ssk, skb);
1319 nlk->netlink_rcv(skb);
1320 consume_skb(skb);
1321 } else {
1322 kfree_skb(skb);
1323 }
1324 sock_put(sk);
1325 return ret;
1326}
1327
1328int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1329 u32 portid, int nonblock)
1330{
1331 struct sock *sk;
1332 int err;
1333 long timeo;
1334
1335 skb = netlink_trim(skb, gfp_any());
1336
1337 timeo = sock_sndtimeo(ssk, nonblock);
1338retry:
1339 sk = netlink_getsockbyportid(ssk, portid);
1340 if (IS_ERR(sk)) {
1341 kfree_skb(skb);
1342 return PTR_ERR(sk);
1343 }
1344 if (netlink_is_kernel(sk))
1345 return netlink_unicast_kernel(sk, skb, ssk);
1346
1347 if (sk_filter(sk, skb)) {
1348 err = skb->len;
1349 kfree_skb(skb);
1350 sock_put(sk);
1351 return err;
1352 }
1353
1354 err = netlink_attachskb(sk, skb, &timeo, ssk);
1355 if (err == 1)
1356 goto retry;
1357 if (err)
1358 return err;
1359
1360 return netlink_sendskb(sk, skb);
1361}
1362EXPORT_SYMBOL(netlink_unicast);
1363
1364int netlink_has_listeners(struct sock *sk, unsigned int group)
1365{
1366 int res = 0;
1367 struct listeners *listeners;
1368
1369 BUG_ON(!netlink_is_kernel(sk));
1370
1371 rcu_read_lock();
1372 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1373
1374 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1375 res = test_bit(group - 1, listeners->masks);
1376
1377 rcu_read_unlock();
1378
1379 return res;
1380}
1381EXPORT_SYMBOL_GPL(netlink_has_listeners);
1382
1383bool netlink_strict_get_check(struct sk_buff *skb)
1384{
1385 const struct netlink_sock *nlk = nlk_sk(NETLINK_CB(skb).sk);
1386
1387 return nlk->flags & NETLINK_F_STRICT_CHK;
1388}
1389EXPORT_SYMBOL_GPL(netlink_strict_get_check);
1390
1391static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1392{
1393 struct netlink_sock *nlk = nlk_sk(sk);
1394
1395 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1396 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1397 netlink_skb_set_owner_r(skb, sk);
1398 __netlink_sendskb(sk, skb);
1399 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1400 }
1401 return -1;
1402}
1403
1404struct netlink_broadcast_data {
1405 struct sock *exclude_sk;
1406 struct net *net;
1407 u32 portid;
1408 u32 group;
1409 int failure;
1410 int delivery_failure;
1411 int congested;
1412 int delivered;
1413 gfp_t allocation;
1414 struct sk_buff *skb, *skb2;
1415 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1416 void *tx_data;
1417};
1418
1419static void do_one_broadcast(struct sock *sk,
1420 struct netlink_broadcast_data *p)
1421{
1422 struct netlink_sock *nlk = nlk_sk(sk);
1423 int val;
1424
1425 if (p->exclude_sk == sk)
1426 return;
1427
1428 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1429 !test_bit(p->group - 1, nlk->groups))
1430 return;
1431
1432 if (!net_eq(sock_net(sk), p->net)) {
1433 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1434 return;
1435
1436 if (!peernet_has_id(sock_net(sk), p->net))
1437 return;
1438
1439 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1440 CAP_NET_BROADCAST))
1441 return;
1442 }
1443
1444 if (p->failure) {
1445 netlink_overrun(sk);
1446 return;
1447 }
1448
1449 sock_hold(sk);
1450 if (p->skb2 == NULL) {
1451 if (skb_shared(p->skb)) {
1452 p->skb2 = skb_clone(p->skb, p->allocation);
1453 } else {
1454 p->skb2 = skb_get(p->skb);
1455 /*
1456 * skb ownership may have been set when
1457 * delivered to a previous socket.
1458 */
1459 skb_orphan(p->skb2);
1460 }
1461 }
1462 if (p->skb2 == NULL) {
1463 netlink_overrun(sk);
1464 /* Clone failed. Notify ALL listeners. */
1465 p->failure = 1;
1466 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1467 p->delivery_failure = 1;
1468 goto out;
1469 }
1470 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1471 kfree_skb(p->skb2);
1472 p->skb2 = NULL;
1473 goto out;
1474 }
1475 if (sk_filter(sk, p->skb2)) {
1476 kfree_skb(p->skb2);
1477 p->skb2 = NULL;
1478 goto out;
1479 }
1480 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1481 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
1482 NETLINK_CB(p->skb2).nsid_is_set = true;
1483 val = netlink_broadcast_deliver(sk, p->skb2);
1484 if (val < 0) {
1485 netlink_overrun(sk);
1486 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1487 p->delivery_failure = 1;
1488 } else {
1489 p->congested |= val;
1490 p->delivered = 1;
1491 p->skb2 = NULL;
1492 }
1493out:
1494 sock_put(sk);
1495}
1496
1497int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1498 u32 group, gfp_t allocation,
1499 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1500 void *filter_data)
1501{
1502 struct net *net = sock_net(ssk);
1503 struct netlink_broadcast_data info;
1504 struct sock *sk;
1505
1506 skb = netlink_trim(skb, allocation);
1507
1508 info.exclude_sk = ssk;
1509 info.net = net;
1510 info.portid = portid;
1511 info.group = group;
1512 info.failure = 0;
1513 info.delivery_failure = 0;
1514 info.congested = 0;
1515 info.delivered = 0;
1516 info.allocation = allocation;
1517 info.skb = skb;
1518 info.skb2 = NULL;
1519 info.tx_filter = filter;
1520 info.tx_data = filter_data;
1521
1522 /* While we sleep in clone, do not allow to change socket list */
1523
1524 netlink_lock_table();
1525
1526 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1527 do_one_broadcast(sk, &info);
1528
1529 consume_skb(skb);
1530
1531 netlink_unlock_table();
1532
1533 if (info.delivery_failure) {
1534 kfree_skb(info.skb2);
1535 return -ENOBUFS;
1536 }
1537 consume_skb(info.skb2);
1538
1539 if (info.delivered) {
1540 if (info.congested && gfpflags_allow_blocking(allocation))
1541 yield();
1542 return 0;
1543 }
1544 return -ESRCH;
1545}
1546EXPORT_SYMBOL(netlink_broadcast_filtered);
1547
1548int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1549 u32 group, gfp_t allocation)
1550{
1551 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1552 NULL, NULL);
1553}
1554EXPORT_SYMBOL(netlink_broadcast);
1555
1556struct netlink_set_err_data {
1557 struct sock *exclude_sk;
1558 u32 portid;
1559 u32 group;
1560 int code;
1561};
1562
1563static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1564{
1565 struct netlink_sock *nlk = nlk_sk(sk);
1566 int ret = 0;
1567
1568 if (sk == p->exclude_sk)
1569 goto out;
1570
1571 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1572 goto out;
1573
1574 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1575 !test_bit(p->group - 1, nlk->groups))
1576 goto out;
1577
1578 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1579 ret = 1;
1580 goto out;
1581 }
1582
1583 sk->sk_err = p->code;
1584 sk_error_report(sk);
1585out:
1586 return ret;
1587}
1588
1589/**
1590 * netlink_set_err - report error to broadcast listeners
1591 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1592 * @portid: the PORTID of a process that we want to skip (if any)
1593 * @group: the broadcast group that will notice the error
1594 * @code: error code, must be negative (as usual in kernelspace)
1595 *
1596 * This function returns the number of broadcast listeners that have set the
1597 * NETLINK_NO_ENOBUFS socket option.
1598 */
1599int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1600{
1601 struct netlink_set_err_data info;
1602 struct sock *sk;
1603 int ret = 0;
1604
1605 info.exclude_sk = ssk;
1606 info.portid = portid;
1607 info.group = group;
1608 /* sk->sk_err wants a positive error value */
1609 info.code = -code;
1610
1611 read_lock(&nl_table_lock);
1612
1613 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1614 ret += do_one_set_err(sk, &info);
1615
1616 read_unlock(&nl_table_lock);
1617 return ret;
1618}
1619EXPORT_SYMBOL(netlink_set_err);
1620
1621/* must be called with netlink table grabbed */
1622static void netlink_update_socket_mc(struct netlink_sock *nlk,
1623 unsigned int group,
1624 int is_new)
1625{
1626 int old, new = !!is_new, subscriptions;
1627
1628 old = test_bit(group - 1, nlk->groups);
1629 subscriptions = nlk->subscriptions - old + new;
1630 if (new)
1631 __set_bit(group - 1, nlk->groups);
1632 else
1633 __clear_bit(group - 1, nlk->groups);
1634 netlink_update_subscriptions(&nlk->sk, subscriptions);
1635 netlink_update_listeners(&nlk->sk);
1636}
1637
1638static int netlink_setsockopt(struct socket *sock, int level, int optname,
1639 sockptr_t optval, unsigned int optlen)
1640{
1641 struct sock *sk = sock->sk;
1642 struct netlink_sock *nlk = nlk_sk(sk);
1643 unsigned int val = 0;
1644 int err;
1645
1646 if (level != SOL_NETLINK)
1647 return -ENOPROTOOPT;
1648
1649 if (optlen >= sizeof(int) &&
1650 copy_from_sockptr(&val, optval, sizeof(val)))
1651 return -EFAULT;
1652
1653 switch (optname) {
1654 case NETLINK_PKTINFO:
1655 if (val)
1656 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1657 else
1658 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1659 err = 0;
1660 break;
1661 case NETLINK_ADD_MEMBERSHIP:
1662 case NETLINK_DROP_MEMBERSHIP: {
1663 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1664 return -EPERM;
1665 err = netlink_realloc_groups(sk);
1666 if (err)
1667 return err;
1668 if (!val || val - 1 >= nlk->ngroups)
1669 return -EINVAL;
1670 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1671 err = nlk->netlink_bind(sock_net(sk), val);
1672 if (err)
1673 return err;
1674 }
1675 netlink_table_grab();
1676 netlink_update_socket_mc(nlk, val,
1677 optname == NETLINK_ADD_MEMBERSHIP);
1678 netlink_table_ungrab();
1679 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1680 nlk->netlink_unbind(sock_net(sk), val);
1681
1682 err = 0;
1683 break;
1684 }
1685 case NETLINK_BROADCAST_ERROR:
1686 if (val)
1687 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1688 else
1689 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1690 err = 0;
1691 break;
1692 case NETLINK_NO_ENOBUFS:
1693 if (val) {
1694 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1695 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1696 wake_up_interruptible(&nlk->wait);
1697 } else {
1698 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1699 }
1700 err = 0;
1701 break;
1702 case NETLINK_LISTEN_ALL_NSID:
1703 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1704 return -EPERM;
1705
1706 if (val)
1707 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1708 else
1709 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1710 err = 0;
1711 break;
1712 case NETLINK_CAP_ACK:
1713 if (val)
1714 nlk->flags |= NETLINK_F_CAP_ACK;
1715 else
1716 nlk->flags &= ~NETLINK_F_CAP_ACK;
1717 err = 0;
1718 break;
1719 case NETLINK_EXT_ACK:
1720 if (val)
1721 nlk->flags |= NETLINK_F_EXT_ACK;
1722 else
1723 nlk->flags &= ~NETLINK_F_EXT_ACK;
1724 err = 0;
1725 break;
1726 case NETLINK_GET_STRICT_CHK:
1727 if (val)
1728 nlk->flags |= NETLINK_F_STRICT_CHK;
1729 else
1730 nlk->flags &= ~NETLINK_F_STRICT_CHK;
1731 err = 0;
1732 break;
1733 default:
1734 err = -ENOPROTOOPT;
1735 }
1736 return err;
1737}
1738
1739static int netlink_getsockopt(struct socket *sock, int level, int optname,
1740 char __user *optval, int __user *optlen)
1741{
1742 struct sock *sk = sock->sk;
1743 struct netlink_sock *nlk = nlk_sk(sk);
1744 int len, val, err;
1745
1746 if (level != SOL_NETLINK)
1747 return -ENOPROTOOPT;
1748
1749 if (get_user(len, optlen))
1750 return -EFAULT;
1751 if (len < 0)
1752 return -EINVAL;
1753
1754 switch (optname) {
1755 case NETLINK_PKTINFO:
1756 if (len < sizeof(int))
1757 return -EINVAL;
1758 len = sizeof(int);
1759 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1760 if (put_user(len, optlen) ||
1761 put_user(val, optval))
1762 return -EFAULT;
1763 err = 0;
1764 break;
1765 case NETLINK_BROADCAST_ERROR:
1766 if (len < sizeof(int))
1767 return -EINVAL;
1768 len = sizeof(int);
1769 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1770 if (put_user(len, optlen) ||
1771 put_user(val, optval))
1772 return -EFAULT;
1773 err = 0;
1774 break;
1775 case NETLINK_NO_ENOBUFS:
1776 if (len < sizeof(int))
1777 return -EINVAL;
1778 len = sizeof(int);
1779 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1780 if (put_user(len, optlen) ||
1781 put_user(val, optval))
1782 return -EFAULT;
1783 err = 0;
1784 break;
1785 case NETLINK_LIST_MEMBERSHIPS: {
1786 int pos, idx, shift;
1787
1788 err = 0;
1789 netlink_lock_table();
1790 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1791 if (len - pos < sizeof(u32))
1792 break;
1793
1794 idx = pos / sizeof(unsigned long);
1795 shift = (pos % sizeof(unsigned long)) * 8;
1796 if (put_user((u32)(nlk->groups[idx] >> shift),
1797 (u32 __user *)(optval + pos))) {
1798 err = -EFAULT;
1799 break;
1800 }
1801 }
1802 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1803 err = -EFAULT;
1804 netlink_unlock_table();
1805 break;
1806 }
1807 case NETLINK_CAP_ACK:
1808 if (len < sizeof(int))
1809 return -EINVAL;
1810 len = sizeof(int);
1811 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1812 if (put_user(len, optlen) ||
1813 put_user(val, optval))
1814 return -EFAULT;
1815 err = 0;
1816 break;
1817 case NETLINK_EXT_ACK:
1818 if (len < sizeof(int))
1819 return -EINVAL;
1820 len = sizeof(int);
1821 val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0;
1822 if (put_user(len, optlen) || put_user(val, optval))
1823 return -EFAULT;
1824 err = 0;
1825 break;
1826 case NETLINK_GET_STRICT_CHK:
1827 if (len < sizeof(int))
1828 return -EINVAL;
1829 len = sizeof(int);
1830 val = nlk->flags & NETLINK_F_STRICT_CHK ? 1 : 0;
1831 if (put_user(len, optlen) || put_user(val, optval))
1832 return -EFAULT;
1833 err = 0;
1834 break;
1835 default:
1836 err = -ENOPROTOOPT;
1837 }
1838 return err;
1839}
1840
1841static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1842{
1843 struct nl_pktinfo info;
1844
1845 info.group = NETLINK_CB(skb).dst_group;
1846 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1847}
1848
1849static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1850 struct sk_buff *skb)
1851{
1852 if (!NETLINK_CB(skb).nsid_is_set)
1853 return;
1854
1855 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1856 &NETLINK_CB(skb).nsid);
1857}
1858
1859static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1860{
1861 struct sock *sk = sock->sk;
1862 struct netlink_sock *nlk = nlk_sk(sk);
1863 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1864 u32 dst_portid;
1865 u32 dst_group;
1866 struct sk_buff *skb;
1867 int err;
1868 struct scm_cookie scm;
1869 u32 netlink_skb_flags = 0;
1870
1871 if (msg->msg_flags & MSG_OOB)
1872 return -EOPNOTSUPP;
1873
1874 err = scm_send(sock, msg, &scm, true);
1875 if (err < 0)
1876 return err;
1877
1878 if (msg->msg_namelen) {
1879 err = -EINVAL;
1880 if (msg->msg_namelen < sizeof(struct sockaddr_nl))
1881 goto out;
1882 if (addr->nl_family != AF_NETLINK)
1883 goto out;
1884 dst_portid = addr->nl_pid;
1885 dst_group = ffs(addr->nl_groups);
1886 err = -EPERM;
1887 if ((dst_group || dst_portid) &&
1888 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1889 goto out;
1890 netlink_skb_flags |= NETLINK_SKB_DST;
1891 } else {
1892 dst_portid = nlk->dst_portid;
1893 dst_group = nlk->dst_group;
1894 }
1895
1896 /* Paired with WRITE_ONCE() in netlink_insert() */
1897 if (!READ_ONCE(nlk->bound)) {
1898 err = netlink_autobind(sock);
1899 if (err)
1900 goto out;
1901 } else {
1902 /* Ensure nlk is hashed and visible. */
1903 smp_rmb();
1904 }
1905
1906 err = -EMSGSIZE;
1907 if (len > sk->sk_sndbuf - 32)
1908 goto out;
1909 err = -ENOBUFS;
1910 skb = netlink_alloc_large_skb(len, dst_group);
1911 if (skb == NULL)
1912 goto out;
1913
1914 NETLINK_CB(skb).portid = nlk->portid;
1915 NETLINK_CB(skb).dst_group = dst_group;
1916 NETLINK_CB(skb).creds = scm.creds;
1917 NETLINK_CB(skb).flags = netlink_skb_flags;
1918
1919 err = -EFAULT;
1920 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1921 kfree_skb(skb);
1922 goto out;
1923 }
1924
1925 err = security_netlink_send(sk, skb);
1926 if (err) {
1927 kfree_skb(skb);
1928 goto out;
1929 }
1930
1931 if (dst_group) {
1932 refcount_inc(&skb->users);
1933 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1934 }
1935 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags & MSG_DONTWAIT);
1936
1937out:
1938 scm_destroy(&scm);
1939 return err;
1940}
1941
1942static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1943 int flags)
1944{
1945 struct scm_cookie scm;
1946 struct sock *sk = sock->sk;
1947 struct netlink_sock *nlk = nlk_sk(sk);
1948 int noblock = flags & MSG_DONTWAIT;
1949 size_t copied;
1950 struct sk_buff *skb, *data_skb;
1951 int err, ret;
1952
1953 if (flags & MSG_OOB)
1954 return -EOPNOTSUPP;
1955
1956 copied = 0;
1957
1958 skb = skb_recv_datagram(sk, flags, noblock, &err);
1959 if (skb == NULL)
1960 goto out;
1961
1962 data_skb = skb;
1963
1964#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1965 if (unlikely(skb_shinfo(skb)->frag_list)) {
1966 /*
1967 * If this skb has a frag_list, then here that means that we
1968 * will have to use the frag_list skb's data for compat tasks
1969 * and the regular skb's data for normal (non-compat) tasks.
1970 *
1971 * If we need to send the compat skb, assign it to the
1972 * 'data_skb' variable so that it will be used below for data
1973 * copying. We keep 'skb' for everything else, including
1974 * freeing both later.
1975 */
1976 if (flags & MSG_CMSG_COMPAT)
1977 data_skb = skb_shinfo(skb)->frag_list;
1978 }
1979#endif
1980
1981 /* Record the max length of recvmsg() calls for future allocations */
1982 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1983 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1984 SKB_WITH_OVERHEAD(32768));
1985
1986 copied = data_skb->len;
1987 if (len < copied) {
1988 msg->msg_flags |= MSG_TRUNC;
1989 copied = len;
1990 }
1991
1992 skb_reset_transport_header(data_skb);
1993 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1994
1995 if (msg->msg_name) {
1996 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1997 addr->nl_family = AF_NETLINK;
1998 addr->nl_pad = 0;
1999 addr->nl_pid = NETLINK_CB(skb).portid;
2000 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
2001 msg->msg_namelen = sizeof(*addr);
2002 }
2003
2004 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
2005 netlink_cmsg_recv_pktinfo(msg, skb);
2006 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
2007 netlink_cmsg_listen_all_nsid(sk, msg, skb);
2008
2009 memset(&scm, 0, sizeof(scm));
2010 scm.creds = *NETLINK_CREDS(skb);
2011 if (flags & MSG_TRUNC)
2012 copied = data_skb->len;
2013
2014 skb_free_datagram(sk, skb);
2015
2016 if (nlk->cb_running &&
2017 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
2018 ret = netlink_dump(sk);
2019 if (ret) {
2020 sk->sk_err = -ret;
2021 sk_error_report(sk);
2022 }
2023 }
2024
2025 scm_recv(sock, msg, &scm, flags);
2026out:
2027 netlink_rcv_wake(sk);
2028 return err ? : copied;
2029}
2030
2031static void netlink_data_ready(struct sock *sk)
2032{
2033 BUG();
2034}
2035
2036/*
2037 * We export these functions to other modules. They provide a
2038 * complete set of kernel non-blocking support for message
2039 * queueing.
2040 */
2041
2042struct sock *
2043__netlink_kernel_create(struct net *net, int unit, struct module *module,
2044 struct netlink_kernel_cfg *cfg)
2045{
2046 struct socket *sock;
2047 struct sock *sk;
2048 struct netlink_sock *nlk;
2049 struct listeners *listeners = NULL;
2050 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2051 unsigned int groups;
2052
2053 BUG_ON(!nl_table);
2054
2055 if (unit < 0 || unit >= MAX_LINKS)
2056 return NULL;
2057
2058 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2059 return NULL;
2060
2061 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
2062 goto out_sock_release_nosk;
2063
2064 sk = sock->sk;
2065
2066 if (!cfg || cfg->groups < 32)
2067 groups = 32;
2068 else
2069 groups = cfg->groups;
2070
2071 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2072 if (!listeners)
2073 goto out_sock_release;
2074
2075 sk->sk_data_ready = netlink_data_ready;
2076 if (cfg && cfg->input)
2077 nlk_sk(sk)->netlink_rcv = cfg->input;
2078
2079 if (netlink_insert(sk, 0))
2080 goto out_sock_release;
2081
2082 nlk = nlk_sk(sk);
2083 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
2084
2085 netlink_table_grab();
2086 if (!nl_table[unit].registered) {
2087 nl_table[unit].groups = groups;
2088 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2089 nl_table[unit].cb_mutex = cb_mutex;
2090 nl_table[unit].module = module;
2091 if (cfg) {
2092 nl_table[unit].bind = cfg->bind;
2093 nl_table[unit].unbind = cfg->unbind;
2094 nl_table[unit].flags = cfg->flags;
2095 if (cfg->compare)
2096 nl_table[unit].compare = cfg->compare;
2097 }
2098 nl_table[unit].registered = 1;
2099 } else {
2100 kfree(listeners);
2101 nl_table[unit].registered++;
2102 }
2103 netlink_table_ungrab();
2104 return sk;
2105
2106out_sock_release:
2107 kfree(listeners);
2108 netlink_kernel_release(sk);
2109 return NULL;
2110
2111out_sock_release_nosk:
2112 sock_release(sock);
2113 return NULL;
2114}
2115EXPORT_SYMBOL(__netlink_kernel_create);
2116
2117void
2118netlink_kernel_release(struct sock *sk)
2119{
2120 if (sk == NULL || sk->sk_socket == NULL)
2121 return;
2122
2123 sock_release(sk->sk_socket);
2124}
2125EXPORT_SYMBOL(netlink_kernel_release);
2126
2127int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2128{
2129 struct listeners *new, *old;
2130 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2131
2132 if (groups < 32)
2133 groups = 32;
2134
2135 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2136 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2137 if (!new)
2138 return -ENOMEM;
2139 old = nl_deref_protected(tbl->listeners);
2140 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2141 rcu_assign_pointer(tbl->listeners, new);
2142
2143 kfree_rcu(old, rcu);
2144 }
2145 tbl->groups = groups;
2146
2147 return 0;
2148}
2149
2150/**
2151 * netlink_change_ngroups - change number of multicast groups
2152 *
2153 * This changes the number of multicast groups that are available
2154 * on a certain netlink family. Note that it is not possible to
2155 * change the number of groups to below 32. Also note that it does
2156 * not implicitly call netlink_clear_multicast_users() when the
2157 * number of groups is reduced.
2158 *
2159 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2160 * @groups: The new number of groups.
2161 */
2162int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2163{
2164 int err;
2165
2166 netlink_table_grab();
2167 err = __netlink_change_ngroups(sk, groups);
2168 netlink_table_ungrab();
2169
2170 return err;
2171}
2172
2173void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2174{
2175 struct sock *sk;
2176 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2177
2178 sk_for_each_bound(sk, &tbl->mc_list)
2179 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2180}
2181
2182struct nlmsghdr *
2183__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2184{
2185 struct nlmsghdr *nlh;
2186 int size = nlmsg_msg_size(len);
2187
2188 nlh = skb_put(skb, NLMSG_ALIGN(size));
2189 nlh->nlmsg_type = type;
2190 nlh->nlmsg_len = size;
2191 nlh->nlmsg_flags = flags;
2192 nlh->nlmsg_pid = portid;
2193 nlh->nlmsg_seq = seq;
2194 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2195 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2196 return nlh;
2197}
2198EXPORT_SYMBOL(__nlmsg_put);
2199
2200/*
2201 * It looks a bit ugly.
2202 * It would be better to create kernel thread.
2203 */
2204
2205static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb,
2206 struct netlink_callback *cb,
2207 struct netlink_ext_ack *extack)
2208{
2209 struct nlmsghdr *nlh;
2210
2211 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(nlk->dump_done_errno),
2212 NLM_F_MULTI | cb->answer_flags);
2213 if (WARN_ON(!nlh))
2214 return -ENOBUFS;
2215
2216 nl_dump_check_consistent(cb, nlh);
2217 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, sizeof(nlk->dump_done_errno));
2218
2219 if (extack->_msg && nlk->flags & NETLINK_F_EXT_ACK) {
2220 nlh->nlmsg_flags |= NLM_F_ACK_TLVS;
2221 if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg))
2222 nlmsg_end(skb, nlh);
2223 }
2224
2225 return 0;
2226}
2227
2228static int netlink_dump(struct sock *sk)
2229{
2230 struct netlink_sock *nlk = nlk_sk(sk);
2231 struct netlink_ext_ack extack = {};
2232 struct netlink_callback *cb;
2233 struct sk_buff *skb = NULL;
2234 struct module *module;
2235 int err = -ENOBUFS;
2236 int alloc_min_size;
2237 int alloc_size;
2238
2239 mutex_lock(nlk->cb_mutex);
2240 if (!nlk->cb_running) {
2241 err = -EINVAL;
2242 goto errout_skb;
2243 }
2244
2245 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2246 goto errout_skb;
2247
2248 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2249 * required, but it makes sense to _attempt_ a 16K bytes allocation
2250 * to reduce number of system calls on dump operations, if user
2251 * ever provided a big enough buffer.
2252 */
2253 cb = &nlk->cb;
2254 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2255
2256 if (alloc_min_size < nlk->max_recvmsg_len) {
2257 alloc_size = nlk->max_recvmsg_len;
2258 skb = alloc_skb(alloc_size,
2259 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2260 __GFP_NOWARN | __GFP_NORETRY);
2261 }
2262 if (!skb) {
2263 alloc_size = alloc_min_size;
2264 skb = alloc_skb(alloc_size, GFP_KERNEL);
2265 }
2266 if (!skb)
2267 goto errout_skb;
2268
2269 /* Trim skb to allocated size. User is expected to provide buffer as
2270 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2271 * netlink_recvmsg())). dump will pack as many smaller messages as
2272 * could fit within the allocated skb. skb is typically allocated
2273 * with larger space than required (could be as much as near 2x the
2274 * requested size with align to next power of 2 approach). Allowing
2275 * dump to use the excess space makes it difficult for a user to have a
2276 * reasonable static buffer based on the expected largest dump of a
2277 * single netdev. The outcome is MSG_TRUNC error.
2278 */
2279 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2280 netlink_skb_set_owner_r(skb, sk);
2281
2282 if (nlk->dump_done_errno > 0) {
2283 cb->extack = &extack;
2284 nlk->dump_done_errno = cb->dump(skb, cb);
2285 cb->extack = NULL;
2286 }
2287
2288 if (nlk->dump_done_errno > 0 ||
2289 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
2290 mutex_unlock(nlk->cb_mutex);
2291
2292 if (sk_filter(sk, skb))
2293 kfree_skb(skb);
2294 else
2295 __netlink_sendskb(sk, skb);
2296 return 0;
2297 }
2298
2299 if (netlink_dump_done(nlk, skb, cb, &extack))
2300 goto errout_skb;
2301
2302#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2303 /* frag_list skb's data is used for compat tasks
2304 * and the regular skb's data for normal (non-compat) tasks.
2305 * See netlink_recvmsg().
2306 */
2307 if (unlikely(skb_shinfo(skb)->frag_list)) {
2308 if (netlink_dump_done(nlk, skb_shinfo(skb)->frag_list, cb, &extack))
2309 goto errout_skb;
2310 }
2311#endif
2312
2313 if (sk_filter(sk, skb))
2314 kfree_skb(skb);
2315 else
2316 __netlink_sendskb(sk, skb);
2317
2318 if (cb->done)
2319 cb->done(cb);
2320
2321 nlk->cb_running = false;
2322 module = cb->module;
2323 skb = cb->skb;
2324 mutex_unlock(nlk->cb_mutex);
2325 module_put(module);
2326 consume_skb(skb);
2327 return 0;
2328
2329errout_skb:
2330 mutex_unlock(nlk->cb_mutex);
2331 kfree_skb(skb);
2332 return err;
2333}
2334
2335int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2336 const struct nlmsghdr *nlh,
2337 struct netlink_dump_control *control)
2338{
2339 struct netlink_sock *nlk, *nlk2;
2340 struct netlink_callback *cb;
2341 struct sock *sk;
2342 int ret;
2343
2344 refcount_inc(&skb->users);
2345
2346 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2347 if (sk == NULL) {
2348 ret = -ECONNREFUSED;
2349 goto error_free;
2350 }
2351
2352 nlk = nlk_sk(sk);
2353 mutex_lock(nlk->cb_mutex);
2354 /* A dump is in progress... */
2355 if (nlk->cb_running) {
2356 ret = -EBUSY;
2357 goto error_unlock;
2358 }
2359 /* add reference of module which cb->dump belongs to */
2360 if (!try_module_get(control->module)) {
2361 ret = -EPROTONOSUPPORT;
2362 goto error_unlock;
2363 }
2364
2365 cb = &nlk->cb;
2366 memset(cb, 0, sizeof(*cb));
2367 cb->dump = control->dump;
2368 cb->done = control->done;
2369 cb->nlh = nlh;
2370 cb->data = control->data;
2371 cb->module = control->module;
2372 cb->min_dump_alloc = control->min_dump_alloc;
2373 cb->skb = skb;
2374
2375 nlk2 = nlk_sk(NETLINK_CB(skb).sk);
2376 cb->strict_check = !!(nlk2->flags & NETLINK_F_STRICT_CHK);
2377
2378 if (control->start) {
2379 ret = control->start(cb);
2380 if (ret)
2381 goto error_put;
2382 }
2383
2384 nlk->cb_running = true;
2385 nlk->dump_done_errno = INT_MAX;
2386
2387 mutex_unlock(nlk->cb_mutex);
2388
2389 ret = netlink_dump(sk);
2390
2391 sock_put(sk);
2392
2393 if (ret)
2394 return ret;
2395
2396 /* We successfully started a dump, by returning -EINTR we
2397 * signal not to send ACK even if it was requested.
2398 */
2399 return -EINTR;
2400
2401error_put:
2402 module_put(control->module);
2403error_unlock:
2404 sock_put(sk);
2405 mutex_unlock(nlk->cb_mutex);
2406error_free:
2407 kfree_skb(skb);
2408 return ret;
2409}
2410EXPORT_SYMBOL(__netlink_dump_start);
2411
2412void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
2413 const struct netlink_ext_ack *extack)
2414{
2415 struct sk_buff *skb;
2416 struct nlmsghdr *rep;
2417 struct nlmsgerr *errmsg;
2418 size_t payload = sizeof(*errmsg);
2419 size_t tlvlen = 0;
2420 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2421 unsigned int flags = 0;
2422 bool nlk_has_extack = nlk->flags & NETLINK_F_EXT_ACK;
2423
2424 /* Error messages get the original request appened, unless the user
2425 * requests to cap the error message, and get extra error data if
2426 * requested.
2427 */
2428 if (nlk_has_extack && extack && extack->_msg)
2429 tlvlen += nla_total_size(strlen(extack->_msg) + 1);
2430
2431 if (err && !(nlk->flags & NETLINK_F_CAP_ACK))
2432 payload += nlmsg_len(nlh);
2433 else
2434 flags |= NLM_F_CAPPED;
2435 if (err && nlk_has_extack && extack && extack->bad_attr)
2436 tlvlen += nla_total_size(sizeof(u32));
2437 if (nlk_has_extack && extack && extack->cookie_len)
2438 tlvlen += nla_total_size(extack->cookie_len);
2439 if (err && nlk_has_extack && extack && extack->policy)
2440 tlvlen += netlink_policy_dump_attr_size_estimate(extack->policy);
2441
2442 if (tlvlen)
2443 flags |= NLM_F_ACK_TLVS;
2444
2445 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
2446 if (!skb) {
2447 NETLINK_CB(in_skb).sk->sk_err = ENOBUFS;
2448 sk_error_report(NETLINK_CB(in_skb).sk);
2449 return;
2450 }
2451
2452 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2453 NLMSG_ERROR, payload, flags);
2454 errmsg = nlmsg_data(rep);
2455 errmsg->error = err;
2456 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2457
2458 if (nlk_has_extack && extack) {
2459 if (extack->_msg) {
2460 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
2461 extack->_msg));
2462 }
2463 if (err && extack->bad_attr &&
2464 !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
2465 (u8 *)extack->bad_attr >= in_skb->data +
2466 in_skb->len))
2467 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
2468 (u8 *)extack->bad_attr -
2469 (u8 *)nlh));
2470 if (extack->cookie_len)
2471 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
2472 extack->cookie_len, extack->cookie));
2473 if (extack->policy)
2474 netlink_policy_dump_write_attr(skb, extack->policy,
2475 NLMSGERR_ATTR_POLICY);
2476 }
2477
2478 nlmsg_end(skb, rep);
2479
2480 nlmsg_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid);
2481}
2482EXPORT_SYMBOL(netlink_ack);
2483
2484int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2485 struct nlmsghdr *,
2486 struct netlink_ext_ack *))
2487{
2488 struct netlink_ext_ack extack;
2489 struct nlmsghdr *nlh;
2490 int err;
2491
2492 while (skb->len >= nlmsg_total_size(0)) {
2493 int msglen;
2494
2495 memset(&extack, 0, sizeof(extack));
2496 nlh = nlmsg_hdr(skb);
2497 err = 0;
2498
2499 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2500 return 0;
2501
2502 /* Only requests are handled by the kernel */
2503 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2504 goto ack;
2505
2506 /* Skip control messages */
2507 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2508 goto ack;
2509
2510 err = cb(skb, nlh, &extack);
2511 if (err == -EINTR)
2512 goto skip;
2513
2514ack:
2515 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2516 netlink_ack(skb, nlh, err, &extack);
2517
2518skip:
2519 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2520 if (msglen > skb->len)
2521 msglen = skb->len;
2522 skb_pull(skb, msglen);
2523 }
2524
2525 return 0;
2526}
2527EXPORT_SYMBOL(netlink_rcv_skb);
2528
2529/**
2530 * nlmsg_notify - send a notification netlink message
2531 * @sk: netlink socket to use
2532 * @skb: notification message
2533 * @portid: destination netlink portid for reports or 0
2534 * @group: destination multicast group or 0
2535 * @report: 1 to report back, 0 to disable
2536 * @flags: allocation flags
2537 */
2538int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2539 unsigned int group, int report, gfp_t flags)
2540{
2541 int err = 0;
2542
2543 if (group) {
2544 int exclude_portid = 0;
2545
2546 if (report) {
2547 refcount_inc(&skb->users);
2548 exclude_portid = portid;
2549 }
2550
2551 /* errors reported via destination sk->sk_err, but propagate
2552 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2553 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2554 if (err == -ESRCH)
2555 err = 0;
2556 }
2557
2558 if (report) {
2559 int err2;
2560
2561 err2 = nlmsg_unicast(sk, skb, portid);
2562 if (!err)
2563 err = err2;
2564 }
2565
2566 return err;
2567}
2568EXPORT_SYMBOL(nlmsg_notify);
2569
2570#ifdef CONFIG_PROC_FS
2571struct nl_seq_iter {
2572 struct seq_net_private p;
2573 struct rhashtable_iter hti;
2574 int link;
2575};
2576
2577static void netlink_walk_start(struct nl_seq_iter *iter)
2578{
2579 rhashtable_walk_enter(&nl_table[iter->link].hash, &iter->hti);
2580 rhashtable_walk_start(&iter->hti);
2581}
2582
2583static void netlink_walk_stop(struct nl_seq_iter *iter)
2584{
2585 rhashtable_walk_stop(&iter->hti);
2586 rhashtable_walk_exit(&iter->hti);
2587}
2588
2589static void *__netlink_seq_next(struct seq_file *seq)
2590{
2591 struct nl_seq_iter *iter = seq->private;
2592 struct netlink_sock *nlk;
2593
2594 do {
2595 for (;;) {
2596 nlk = rhashtable_walk_next(&iter->hti);
2597
2598 if (IS_ERR(nlk)) {
2599 if (PTR_ERR(nlk) == -EAGAIN)
2600 continue;
2601
2602 return nlk;
2603 }
2604
2605 if (nlk)
2606 break;
2607
2608 netlink_walk_stop(iter);
2609 if (++iter->link >= MAX_LINKS)
2610 return NULL;
2611
2612 netlink_walk_start(iter);
2613 }
2614 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2615
2616 return nlk;
2617}
2618
2619static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2620 __acquires(RCU)
2621{
2622 struct nl_seq_iter *iter = seq->private;
2623 void *obj = SEQ_START_TOKEN;
2624 loff_t pos;
2625
2626 iter->link = 0;
2627
2628 netlink_walk_start(iter);
2629
2630 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2631 obj = __netlink_seq_next(seq);
2632
2633 return obj;
2634}
2635
2636static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2637{
2638 ++*pos;
2639 return __netlink_seq_next(seq);
2640}
2641
2642static void netlink_native_seq_stop(struct seq_file *seq, void *v)
2643{
2644 struct nl_seq_iter *iter = seq->private;
2645
2646 if (iter->link >= MAX_LINKS)
2647 return;
2648
2649 netlink_walk_stop(iter);
2650}
2651
2652
2653static int netlink_native_seq_show(struct seq_file *seq, void *v)
2654{
2655 if (v == SEQ_START_TOKEN) {
2656 seq_puts(seq,
2657 "sk Eth Pid Groups "
2658 "Rmem Wmem Dump Locks Drops Inode\n");
2659 } else {
2660 struct sock *s = v;
2661 struct netlink_sock *nlk = nlk_sk(s);
2662
2663 seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8u %-8lu\n",
2664 s,
2665 s->sk_protocol,
2666 nlk->portid,
2667 nlk->groups ? (u32)nlk->groups[0] : 0,
2668 sk_rmem_alloc_get(s),
2669 sk_wmem_alloc_get(s),
2670 nlk->cb_running,
2671 refcount_read(&s->sk_refcnt),
2672 atomic_read(&s->sk_drops),
2673 sock_i_ino(s)
2674 );
2675
2676 }
2677 return 0;
2678}
2679
2680#ifdef CONFIG_BPF_SYSCALL
2681struct bpf_iter__netlink {
2682 __bpf_md_ptr(struct bpf_iter_meta *, meta);
2683 __bpf_md_ptr(struct netlink_sock *, sk);
2684};
2685
2686DEFINE_BPF_ITER_FUNC(netlink, struct bpf_iter_meta *meta, struct netlink_sock *sk)
2687
2688static int netlink_prog_seq_show(struct bpf_prog *prog,
2689 struct bpf_iter_meta *meta,
2690 void *v)
2691{
2692 struct bpf_iter__netlink ctx;
2693
2694 meta->seq_num--; /* skip SEQ_START_TOKEN */
2695 ctx.meta = meta;
2696 ctx.sk = nlk_sk((struct sock *)v);
2697 return bpf_iter_run_prog(prog, &ctx);
2698}
2699
2700static int netlink_seq_show(struct seq_file *seq, void *v)
2701{
2702 struct bpf_iter_meta meta;
2703 struct bpf_prog *prog;
2704
2705 meta.seq = seq;
2706 prog = bpf_iter_get_info(&meta, false);
2707 if (!prog)
2708 return netlink_native_seq_show(seq, v);
2709
2710 if (v != SEQ_START_TOKEN)
2711 return netlink_prog_seq_show(prog, &meta, v);
2712
2713 return 0;
2714}
2715
2716static void netlink_seq_stop(struct seq_file *seq, void *v)
2717{
2718 struct bpf_iter_meta meta;
2719 struct bpf_prog *prog;
2720
2721 if (!v) {
2722 meta.seq = seq;
2723 prog = bpf_iter_get_info(&meta, true);
2724 if (prog)
2725 (void)netlink_prog_seq_show(prog, &meta, v);
2726 }
2727
2728 netlink_native_seq_stop(seq, v);
2729}
2730#else
2731static int netlink_seq_show(struct seq_file *seq, void *v)
2732{
2733 return netlink_native_seq_show(seq, v);
2734}
2735
2736static void netlink_seq_stop(struct seq_file *seq, void *v)
2737{
2738 netlink_native_seq_stop(seq, v);
2739}
2740#endif
2741
2742static const struct seq_operations netlink_seq_ops = {
2743 .start = netlink_seq_start,
2744 .next = netlink_seq_next,
2745 .stop = netlink_seq_stop,
2746 .show = netlink_seq_show,
2747};
2748#endif
2749
2750int netlink_register_notifier(struct notifier_block *nb)
2751{
2752 return blocking_notifier_chain_register(&netlink_chain, nb);
2753}
2754EXPORT_SYMBOL(netlink_register_notifier);
2755
2756int netlink_unregister_notifier(struct notifier_block *nb)
2757{
2758 return blocking_notifier_chain_unregister(&netlink_chain, nb);
2759}
2760EXPORT_SYMBOL(netlink_unregister_notifier);
2761
2762static const struct proto_ops netlink_ops = {
2763 .family = PF_NETLINK,
2764 .owner = THIS_MODULE,
2765 .release = netlink_release,
2766 .bind = netlink_bind,
2767 .connect = netlink_connect,
2768 .socketpair = sock_no_socketpair,
2769 .accept = sock_no_accept,
2770 .getname = netlink_getname,
2771 .poll = datagram_poll,
2772 .ioctl = netlink_ioctl,
2773 .listen = sock_no_listen,
2774 .shutdown = sock_no_shutdown,
2775 .setsockopt = netlink_setsockopt,
2776 .getsockopt = netlink_getsockopt,
2777 .sendmsg = netlink_sendmsg,
2778 .recvmsg = netlink_recvmsg,
2779 .mmap = sock_no_mmap,
2780 .sendpage = sock_no_sendpage,
2781};
2782
2783static const struct net_proto_family netlink_family_ops = {
2784 .family = PF_NETLINK,
2785 .create = netlink_create,
2786 .owner = THIS_MODULE, /* for consistency 8) */
2787};
2788
2789static int __net_init netlink_net_init(struct net *net)
2790{
2791#ifdef CONFIG_PROC_FS
2792 if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops,
2793 sizeof(struct nl_seq_iter)))
2794 return -ENOMEM;
2795#endif
2796 return 0;
2797}
2798
2799static void __net_exit netlink_net_exit(struct net *net)
2800{
2801#ifdef CONFIG_PROC_FS
2802 remove_proc_entry("netlink", net->proc_net);
2803#endif
2804}
2805
2806static void __init netlink_add_usersock_entry(void)
2807{
2808 struct listeners *listeners;
2809 int groups = 32;
2810
2811 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2812 if (!listeners)
2813 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2814
2815 netlink_table_grab();
2816
2817 nl_table[NETLINK_USERSOCK].groups = groups;
2818 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2819 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2820 nl_table[NETLINK_USERSOCK].registered = 1;
2821 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2822
2823 netlink_table_ungrab();
2824}
2825
2826static struct pernet_operations __net_initdata netlink_net_ops = {
2827 .init = netlink_net_init,
2828 .exit = netlink_net_exit,
2829};
2830
2831static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2832{
2833 const struct netlink_sock *nlk = data;
2834 struct netlink_compare_arg arg;
2835
2836 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2837 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2838}
2839
2840static const struct rhashtable_params netlink_rhashtable_params = {
2841 .head_offset = offsetof(struct netlink_sock, node),
2842 .key_len = netlink_compare_arg_len,
2843 .obj_hashfn = netlink_hash,
2844 .obj_cmpfn = netlink_compare,
2845 .automatic_shrinking = true,
2846};
2847
2848#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2849BTF_ID_LIST(btf_netlink_sock_id)
2850BTF_ID(struct, netlink_sock)
2851
2852static const struct bpf_iter_seq_info netlink_seq_info = {
2853 .seq_ops = &netlink_seq_ops,
2854 .init_seq_private = bpf_iter_init_seq_net,
2855 .fini_seq_private = bpf_iter_fini_seq_net,
2856 .seq_priv_size = sizeof(struct nl_seq_iter),
2857};
2858
2859static struct bpf_iter_reg netlink_reg_info = {
2860 .target = "netlink",
2861 .ctx_arg_info_size = 1,
2862 .ctx_arg_info = {
2863 { offsetof(struct bpf_iter__netlink, sk),
2864 PTR_TO_BTF_ID_OR_NULL },
2865 },
2866 .seq_info = &netlink_seq_info,
2867};
2868
2869static int __init bpf_iter_register(void)
2870{
2871 netlink_reg_info.ctx_arg_info[0].btf_id = *btf_netlink_sock_id;
2872 return bpf_iter_reg_target(&netlink_reg_info);
2873}
2874#endif
2875
2876static int __init netlink_proto_init(void)
2877{
2878 int i;
2879 int err = proto_register(&netlink_proto, 0);
2880
2881 if (err != 0)
2882 goto out;
2883
2884#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2885 err = bpf_iter_register();
2886 if (err)
2887 goto out;
2888#endif
2889
2890 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof_field(struct sk_buff, cb));
2891
2892 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2893 if (!nl_table)
2894 goto panic;
2895
2896 for (i = 0; i < MAX_LINKS; i++) {
2897 if (rhashtable_init(&nl_table[i].hash,
2898 &netlink_rhashtable_params) < 0) {
2899 while (--i > 0)
2900 rhashtable_destroy(&nl_table[i].hash);
2901 kfree(nl_table);
2902 goto panic;
2903 }
2904 }
2905
2906 netlink_add_usersock_entry();
2907
2908 sock_register(&netlink_family_ops);
2909 register_pernet_subsys(&netlink_net_ops);
2910 register_pernet_subsys(&netlink_tap_net_ops);
2911 /* The netlink device handler may be needed early. */
2912 rtnetlink_init();
2913out:
2914 return err;
2915panic:
2916 panic("netlink_init: Cannot allocate nl_table\n");
2917}
2918
2919core_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 <linux/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 <linux/rhashtable.h>
62#include <asm/cacheflush.h>
63#include <linux/hash.h>
64#include <linux/genetlink.h>
65
66#include <net/net_namespace.h>
67#include <net/sock.h>
68#include <net/scm.h>
69#include <net/netlink.h>
70
71#include "af_netlink.h"
72
73struct listeners {
74 struct rcu_head rcu;
75 unsigned long masks[0];
76};
77
78/* state bits */
79#define NETLINK_S_CONGESTED 0x0
80
81/* flags */
82#define NETLINK_F_KERNEL_SOCKET 0x1
83#define NETLINK_F_RECV_PKTINFO 0x2
84#define NETLINK_F_BROADCAST_SEND_ERROR 0x4
85#define NETLINK_F_RECV_NO_ENOBUFS 0x8
86#define NETLINK_F_LISTEN_ALL_NSID 0x10
87#define NETLINK_F_CAP_ACK 0x20
88
89static inline int netlink_is_kernel(struct sock *sk)
90{
91 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;
92}
93
94struct netlink_table *nl_table __read_mostly;
95EXPORT_SYMBOL_GPL(nl_table);
96
97static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
98
99static int netlink_dump(struct sock *sk);
100static void netlink_skb_destructor(struct sk_buff *skb);
101
102/* nl_table locking explained:
103 * Lookup and traversal are protected with an RCU read-side lock. Insertion
104 * and removal are protected with per bucket lock while using RCU list
105 * modification primitives and may run in parallel to RCU protected lookups.
106 * Destruction of the Netlink socket may only occur *after* nl_table_lock has
107 * been acquired * either during or after the socket has been removed from
108 * the list and after an RCU grace period.
109 */
110DEFINE_RWLOCK(nl_table_lock);
111EXPORT_SYMBOL_GPL(nl_table_lock);
112static atomic_t nl_table_users = ATOMIC_INIT(0);
113
114#define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
115
116static BLOCKING_NOTIFIER_HEAD(netlink_chain);
117
118static DEFINE_SPINLOCK(netlink_tap_lock);
119static struct list_head netlink_tap_all __read_mostly;
120
121static const struct rhashtable_params netlink_rhashtable_params;
122
123static inline u32 netlink_group_mask(u32 group)
124{
125 return group ? 1 << (group - 1) : 0;
126}
127
128static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
129 gfp_t gfp_mask)
130{
131 unsigned int len = skb_end_offset(skb);
132 struct sk_buff *new;
133
134 new = alloc_skb(len, gfp_mask);
135 if (new == NULL)
136 return NULL;
137
138 NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
139 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
140 NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
141
142 memcpy(skb_put(new, len), skb->data, len);
143 return new;
144}
145
146int netlink_add_tap(struct netlink_tap *nt)
147{
148 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
149 return -EINVAL;
150
151 spin_lock(&netlink_tap_lock);
152 list_add_rcu(&nt->list, &netlink_tap_all);
153 spin_unlock(&netlink_tap_lock);
154
155 __module_get(nt->module);
156
157 return 0;
158}
159EXPORT_SYMBOL_GPL(netlink_add_tap);
160
161static int __netlink_remove_tap(struct netlink_tap *nt)
162{
163 bool found = false;
164 struct netlink_tap *tmp;
165
166 spin_lock(&netlink_tap_lock);
167
168 list_for_each_entry(tmp, &netlink_tap_all, list) {
169 if (nt == tmp) {
170 list_del_rcu(&nt->list);
171 found = true;
172 goto out;
173 }
174 }
175
176 pr_warn("__netlink_remove_tap: %p not found\n", nt);
177out:
178 spin_unlock(&netlink_tap_lock);
179
180 if (found)
181 module_put(nt->module);
182
183 return found ? 0 : -ENODEV;
184}
185
186int netlink_remove_tap(struct netlink_tap *nt)
187{
188 int ret;
189
190 ret = __netlink_remove_tap(nt);
191 synchronize_net();
192
193 return ret;
194}
195EXPORT_SYMBOL_GPL(netlink_remove_tap);
196
197static bool netlink_filter_tap(const struct sk_buff *skb)
198{
199 struct sock *sk = skb->sk;
200
201 /* We take the more conservative approach and
202 * whitelist socket protocols that may pass.
203 */
204 switch (sk->sk_protocol) {
205 case NETLINK_ROUTE:
206 case NETLINK_USERSOCK:
207 case NETLINK_SOCK_DIAG:
208 case NETLINK_NFLOG:
209 case NETLINK_XFRM:
210 case NETLINK_FIB_LOOKUP:
211 case NETLINK_NETFILTER:
212 case NETLINK_GENERIC:
213 return true;
214 }
215
216 return false;
217}
218
219static int __netlink_deliver_tap_skb(struct sk_buff *skb,
220 struct net_device *dev)
221{
222 struct sk_buff *nskb;
223 struct sock *sk = skb->sk;
224 int ret = -ENOMEM;
225
226 dev_hold(dev);
227
228 if (is_vmalloc_addr(skb->head))
229 nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
230 else
231 nskb = skb_clone(skb, GFP_ATOMIC);
232 if (nskb) {
233 nskb->dev = dev;
234 nskb->protocol = htons((u16) sk->sk_protocol);
235 nskb->pkt_type = netlink_is_kernel(sk) ?
236 PACKET_KERNEL : PACKET_USER;
237 skb_reset_network_header(nskb);
238 ret = dev_queue_xmit(nskb);
239 if (unlikely(ret > 0))
240 ret = net_xmit_errno(ret);
241 }
242
243 dev_put(dev);
244 return ret;
245}
246
247static void __netlink_deliver_tap(struct sk_buff *skb)
248{
249 int ret;
250 struct netlink_tap *tmp;
251
252 if (!netlink_filter_tap(skb))
253 return;
254
255 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
256 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
257 if (unlikely(ret))
258 break;
259 }
260}
261
262static void netlink_deliver_tap(struct sk_buff *skb)
263{
264 rcu_read_lock();
265
266 if (unlikely(!list_empty(&netlink_tap_all)))
267 __netlink_deliver_tap(skb);
268
269 rcu_read_unlock();
270}
271
272static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
273 struct sk_buff *skb)
274{
275 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
276 netlink_deliver_tap(skb);
277}
278
279static void netlink_overrun(struct sock *sk)
280{
281 struct netlink_sock *nlk = nlk_sk(sk);
282
283 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
284 if (!test_and_set_bit(NETLINK_S_CONGESTED,
285 &nlk_sk(sk)->state)) {
286 sk->sk_err = ENOBUFS;
287 sk->sk_error_report(sk);
288 }
289 }
290 atomic_inc(&sk->sk_drops);
291}
292
293static void netlink_rcv_wake(struct sock *sk)
294{
295 struct netlink_sock *nlk = nlk_sk(sk);
296
297 if (skb_queue_empty(&sk->sk_receive_queue))
298 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
299 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
300 wake_up_interruptible(&nlk->wait);
301}
302
303static void netlink_skb_destructor(struct sk_buff *skb)
304{
305 if (is_vmalloc_addr(skb->head)) {
306 if (!skb->cloned ||
307 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
308 vfree(skb->head);
309
310 skb->head = NULL;
311 }
312 if (skb->sk != NULL)
313 sock_rfree(skb);
314}
315
316static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
317{
318 WARN_ON(skb->sk != NULL);
319 skb->sk = sk;
320 skb->destructor = netlink_skb_destructor;
321 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
322 sk_mem_charge(sk, skb->truesize);
323}
324
325static void netlink_sock_destruct(struct sock *sk)
326{
327 struct netlink_sock *nlk = nlk_sk(sk);
328
329 if (nlk->cb_running) {
330 if (nlk->cb.done)
331 nlk->cb.done(&nlk->cb);
332 module_put(nlk->cb.module);
333 kfree_skb(nlk->cb.skb);
334 }
335
336 skb_queue_purge(&sk->sk_receive_queue);
337
338 if (!sock_flag(sk, SOCK_DEAD)) {
339 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
340 return;
341 }
342
343 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
344 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
345 WARN_ON(nlk_sk(sk)->groups);
346}
347
348static void netlink_sock_destruct_work(struct work_struct *work)
349{
350 struct netlink_sock *nlk = container_of(work, struct netlink_sock,
351 work);
352
353 sk_free(&nlk->sk);
354}
355
356/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
357 * SMP. Look, when several writers sleep and reader wakes them up, all but one
358 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
359 * this, _but_ remember, it adds useless work on UP machines.
360 */
361
362void netlink_table_grab(void)
363 __acquires(nl_table_lock)
364{
365 might_sleep();
366
367 write_lock_irq(&nl_table_lock);
368
369 if (atomic_read(&nl_table_users)) {
370 DECLARE_WAITQUEUE(wait, current);
371
372 add_wait_queue_exclusive(&nl_table_wait, &wait);
373 for (;;) {
374 set_current_state(TASK_UNINTERRUPTIBLE);
375 if (atomic_read(&nl_table_users) == 0)
376 break;
377 write_unlock_irq(&nl_table_lock);
378 schedule();
379 write_lock_irq(&nl_table_lock);
380 }
381
382 __set_current_state(TASK_RUNNING);
383 remove_wait_queue(&nl_table_wait, &wait);
384 }
385}
386
387void netlink_table_ungrab(void)
388 __releases(nl_table_lock)
389{
390 write_unlock_irq(&nl_table_lock);
391 wake_up(&nl_table_wait);
392}
393
394static inline void
395netlink_lock_table(void)
396{
397 /* read_lock() synchronizes us to netlink_table_grab */
398
399 read_lock(&nl_table_lock);
400 atomic_inc(&nl_table_users);
401 read_unlock(&nl_table_lock);
402}
403
404static inline void
405netlink_unlock_table(void)
406{
407 if (atomic_dec_and_test(&nl_table_users))
408 wake_up(&nl_table_wait);
409}
410
411struct netlink_compare_arg
412{
413 possible_net_t pnet;
414 u32 portid;
415};
416
417/* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
418#define netlink_compare_arg_len \
419 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
420
421static inline int netlink_compare(struct rhashtable_compare_arg *arg,
422 const void *ptr)
423{
424 const struct netlink_compare_arg *x = arg->key;
425 const struct netlink_sock *nlk = ptr;
426
427 return nlk->portid != x->portid ||
428 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
429}
430
431static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
432 struct net *net, u32 portid)
433{
434 memset(arg, 0, sizeof(*arg));
435 write_pnet(&arg->pnet, net);
436 arg->portid = portid;
437}
438
439static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
440 struct net *net)
441{
442 struct netlink_compare_arg arg;
443
444 netlink_compare_arg_init(&arg, net, portid);
445 return rhashtable_lookup_fast(&table->hash, &arg,
446 netlink_rhashtable_params);
447}
448
449static int __netlink_insert(struct netlink_table *table, struct sock *sk)
450{
451 struct netlink_compare_arg arg;
452
453 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
454 return rhashtable_lookup_insert_key(&table->hash, &arg,
455 &nlk_sk(sk)->node,
456 netlink_rhashtable_params);
457}
458
459static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
460{
461 struct netlink_table *table = &nl_table[protocol];
462 struct sock *sk;
463
464 rcu_read_lock();
465 sk = __netlink_lookup(table, portid, net);
466 if (sk)
467 sock_hold(sk);
468 rcu_read_unlock();
469
470 return sk;
471}
472
473static const struct proto_ops netlink_ops;
474
475static void
476netlink_update_listeners(struct sock *sk)
477{
478 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
479 unsigned long mask;
480 unsigned int i;
481 struct listeners *listeners;
482
483 listeners = nl_deref_protected(tbl->listeners);
484 if (!listeners)
485 return;
486
487 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
488 mask = 0;
489 sk_for_each_bound(sk, &tbl->mc_list) {
490 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
491 mask |= nlk_sk(sk)->groups[i];
492 }
493 listeners->masks[i] = mask;
494 }
495 /* this function is only called with the netlink table "grabbed", which
496 * makes sure updates are visible before bind or setsockopt return. */
497}
498
499static int netlink_insert(struct sock *sk, u32 portid)
500{
501 struct netlink_table *table = &nl_table[sk->sk_protocol];
502 int err;
503
504 lock_sock(sk);
505
506 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
507 if (nlk_sk(sk)->bound)
508 goto err;
509
510 err = -ENOMEM;
511 if (BITS_PER_LONG > 32 &&
512 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
513 goto err;
514
515 nlk_sk(sk)->portid = portid;
516 sock_hold(sk);
517
518 err = __netlink_insert(table, sk);
519 if (err) {
520 /* In case the hashtable backend returns with -EBUSY
521 * from here, it must not escape to the caller.
522 */
523 if (unlikely(err == -EBUSY))
524 err = -EOVERFLOW;
525 if (err == -EEXIST)
526 err = -EADDRINUSE;
527 sock_put(sk);
528 goto err;
529 }
530
531 /* We need to ensure that the socket is hashed and visible. */
532 smp_wmb();
533 nlk_sk(sk)->bound = portid;
534
535err:
536 release_sock(sk);
537 return err;
538}
539
540static void netlink_remove(struct sock *sk)
541{
542 struct netlink_table *table;
543
544 table = &nl_table[sk->sk_protocol];
545 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
546 netlink_rhashtable_params)) {
547 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
548 __sock_put(sk);
549 }
550
551 netlink_table_grab();
552 if (nlk_sk(sk)->subscriptions) {
553 __sk_del_bind_node(sk);
554 netlink_update_listeners(sk);
555 }
556 if (sk->sk_protocol == NETLINK_GENERIC)
557 atomic_inc(&genl_sk_destructing_cnt);
558 netlink_table_ungrab();
559}
560
561static struct proto netlink_proto = {
562 .name = "NETLINK",
563 .owner = THIS_MODULE,
564 .obj_size = sizeof(struct netlink_sock),
565};
566
567static int __netlink_create(struct net *net, struct socket *sock,
568 struct mutex *cb_mutex, int protocol,
569 int kern)
570{
571 struct sock *sk;
572 struct netlink_sock *nlk;
573
574 sock->ops = &netlink_ops;
575
576 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
577 if (!sk)
578 return -ENOMEM;
579
580 sock_init_data(sock, sk);
581
582 nlk = nlk_sk(sk);
583 if (cb_mutex) {
584 nlk->cb_mutex = cb_mutex;
585 } else {
586 nlk->cb_mutex = &nlk->cb_def_mutex;
587 mutex_init(nlk->cb_mutex);
588 }
589 init_waitqueue_head(&nlk->wait);
590
591 sk->sk_destruct = netlink_sock_destruct;
592 sk->sk_protocol = protocol;
593 return 0;
594}
595
596static int netlink_create(struct net *net, struct socket *sock, int protocol,
597 int kern)
598{
599 struct module *module = NULL;
600 struct mutex *cb_mutex;
601 struct netlink_sock *nlk;
602 int (*bind)(struct net *net, int group);
603 void (*unbind)(struct net *net, int group);
604 int err = 0;
605
606 sock->state = SS_UNCONNECTED;
607
608 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
609 return -ESOCKTNOSUPPORT;
610
611 if (protocol < 0 || protocol >= MAX_LINKS)
612 return -EPROTONOSUPPORT;
613
614 netlink_lock_table();
615#ifdef CONFIG_MODULES
616 if (!nl_table[protocol].registered) {
617 netlink_unlock_table();
618 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
619 netlink_lock_table();
620 }
621#endif
622 if (nl_table[protocol].registered &&
623 try_module_get(nl_table[protocol].module))
624 module = nl_table[protocol].module;
625 else
626 err = -EPROTONOSUPPORT;
627 cb_mutex = nl_table[protocol].cb_mutex;
628 bind = nl_table[protocol].bind;
629 unbind = nl_table[protocol].unbind;
630 netlink_unlock_table();
631
632 if (err < 0)
633 goto out;
634
635 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
636 if (err < 0)
637 goto out_module;
638
639 local_bh_disable();
640 sock_prot_inuse_add(net, &netlink_proto, 1);
641 local_bh_enable();
642
643 nlk = nlk_sk(sock->sk);
644 nlk->module = module;
645 nlk->netlink_bind = bind;
646 nlk->netlink_unbind = unbind;
647out:
648 return err;
649
650out_module:
651 module_put(module);
652 goto out;
653}
654
655static void deferred_put_nlk_sk(struct rcu_head *head)
656{
657 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
658 struct sock *sk = &nlk->sk;
659
660 if (!atomic_dec_and_test(&sk->sk_refcnt))
661 return;
662
663 if (nlk->cb_running && nlk->cb.done) {
664 INIT_WORK(&nlk->work, netlink_sock_destruct_work);
665 schedule_work(&nlk->work);
666 return;
667 }
668
669 sk_free(sk);
670}
671
672static int netlink_release(struct socket *sock)
673{
674 struct sock *sk = sock->sk;
675 struct netlink_sock *nlk;
676
677 if (!sk)
678 return 0;
679
680 netlink_remove(sk);
681 sock_orphan(sk);
682 nlk = nlk_sk(sk);
683
684 /*
685 * OK. Socket is unlinked, any packets that arrive now
686 * will be purged.
687 */
688
689 /* must not acquire netlink_table_lock in any way again before unbind
690 * and notifying genetlink is done as otherwise it might deadlock
691 */
692 if (nlk->netlink_unbind) {
693 int i;
694
695 for (i = 0; i < nlk->ngroups; i++)
696 if (test_bit(i, nlk->groups))
697 nlk->netlink_unbind(sock_net(sk), i + 1);
698 }
699 if (sk->sk_protocol == NETLINK_GENERIC &&
700 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
701 wake_up(&genl_sk_destructing_waitq);
702
703 sock->sk = NULL;
704 wake_up_interruptible_all(&nlk->wait);
705
706 skb_queue_purge(&sk->sk_write_queue);
707
708 if (nlk->portid && nlk->bound) {
709 struct netlink_notify n = {
710 .net = sock_net(sk),
711 .protocol = sk->sk_protocol,
712 .portid = nlk->portid,
713 };
714 blocking_notifier_call_chain(&netlink_chain,
715 NETLINK_URELEASE, &n);
716 }
717
718 module_put(nlk->module);
719
720 if (netlink_is_kernel(sk)) {
721 netlink_table_grab();
722 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
723 if (--nl_table[sk->sk_protocol].registered == 0) {
724 struct listeners *old;
725
726 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
727 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
728 kfree_rcu(old, rcu);
729 nl_table[sk->sk_protocol].module = NULL;
730 nl_table[sk->sk_protocol].bind = NULL;
731 nl_table[sk->sk_protocol].unbind = NULL;
732 nl_table[sk->sk_protocol].flags = 0;
733 nl_table[sk->sk_protocol].registered = 0;
734 }
735 netlink_table_ungrab();
736 }
737
738 kfree(nlk->groups);
739 nlk->groups = NULL;
740
741 local_bh_disable();
742 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
743 local_bh_enable();
744 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
745 return 0;
746}
747
748static int netlink_autobind(struct socket *sock)
749{
750 struct sock *sk = sock->sk;
751 struct net *net = sock_net(sk);
752 struct netlink_table *table = &nl_table[sk->sk_protocol];
753 s32 portid = task_tgid_vnr(current);
754 int err;
755 s32 rover = -4096;
756 bool ok;
757
758retry:
759 cond_resched();
760 rcu_read_lock();
761 ok = !__netlink_lookup(table, portid, net);
762 rcu_read_unlock();
763 if (!ok) {
764 /* Bind collision, search negative portid values. */
765 if (rover == -4096)
766 /* rover will be in range [S32_MIN, -4097] */
767 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
768 else if (rover >= -4096)
769 rover = -4097;
770 portid = rover--;
771 goto retry;
772 }
773
774 err = netlink_insert(sk, portid);
775 if (err == -EADDRINUSE)
776 goto retry;
777
778 /* If 2 threads race to autobind, that is fine. */
779 if (err == -EBUSY)
780 err = 0;
781
782 return err;
783}
784
785/**
786 * __netlink_ns_capable - General netlink message capability test
787 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
788 * @user_ns: The user namespace of the capability to use
789 * @cap: The capability to use
790 *
791 * Test to see if the opener of the socket we received the message
792 * from had when the netlink socket was created and the sender of the
793 * message has has the capability @cap in the user namespace @user_ns.
794 */
795bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
796 struct user_namespace *user_ns, int cap)
797{
798 return ((nsp->flags & NETLINK_SKB_DST) ||
799 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
800 ns_capable(user_ns, cap);
801}
802EXPORT_SYMBOL(__netlink_ns_capable);
803
804/**
805 * netlink_ns_capable - General netlink message capability test
806 * @skb: socket buffer holding a netlink command from userspace
807 * @user_ns: The user namespace of the capability to use
808 * @cap: The capability to use
809 *
810 * Test to see if the opener of the socket we received the message
811 * from had when the netlink socket was created and the sender of the
812 * message has has the capability @cap in the user namespace @user_ns.
813 */
814bool netlink_ns_capable(const struct sk_buff *skb,
815 struct user_namespace *user_ns, int cap)
816{
817 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
818}
819EXPORT_SYMBOL(netlink_ns_capable);
820
821/**
822 * netlink_capable - Netlink global message capability test
823 * @skb: socket buffer holding a netlink command from userspace
824 * @cap: The capability to use
825 *
826 * Test to see if the opener of the socket we received the message
827 * from had when the netlink socket was created and the sender of the
828 * message has has the capability @cap in all user namespaces.
829 */
830bool netlink_capable(const struct sk_buff *skb, int cap)
831{
832 return netlink_ns_capable(skb, &init_user_ns, cap);
833}
834EXPORT_SYMBOL(netlink_capable);
835
836/**
837 * netlink_net_capable - Netlink network namespace message capability test
838 * @skb: socket buffer holding a netlink command from userspace
839 * @cap: The capability to use
840 *
841 * Test to see if the opener of the socket we received the message
842 * from had when the netlink socket was created and the sender of the
843 * message has has the capability @cap over the network namespace of
844 * the socket we received the message from.
845 */
846bool netlink_net_capable(const struct sk_buff *skb, int cap)
847{
848 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
849}
850EXPORT_SYMBOL(netlink_net_capable);
851
852static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
853{
854 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
855 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
856}
857
858static void
859netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
860{
861 struct netlink_sock *nlk = nlk_sk(sk);
862
863 if (nlk->subscriptions && !subscriptions)
864 __sk_del_bind_node(sk);
865 else if (!nlk->subscriptions && subscriptions)
866 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
867 nlk->subscriptions = subscriptions;
868}
869
870static int netlink_realloc_groups(struct sock *sk)
871{
872 struct netlink_sock *nlk = nlk_sk(sk);
873 unsigned int groups;
874 unsigned long *new_groups;
875 int err = 0;
876
877 netlink_table_grab();
878
879 groups = nl_table[sk->sk_protocol].groups;
880 if (!nl_table[sk->sk_protocol].registered) {
881 err = -ENOENT;
882 goto out_unlock;
883 }
884
885 if (nlk->ngroups >= groups)
886 goto out_unlock;
887
888 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
889 if (new_groups == NULL) {
890 err = -ENOMEM;
891 goto out_unlock;
892 }
893 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
894 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
895
896 nlk->groups = new_groups;
897 nlk->ngroups = groups;
898 out_unlock:
899 netlink_table_ungrab();
900 return err;
901}
902
903static void netlink_undo_bind(int group, long unsigned int groups,
904 struct sock *sk)
905{
906 struct netlink_sock *nlk = nlk_sk(sk);
907 int undo;
908
909 if (!nlk->netlink_unbind)
910 return;
911
912 for (undo = 0; undo < group; undo++)
913 if (test_bit(undo, &groups))
914 nlk->netlink_unbind(sock_net(sk), undo + 1);
915}
916
917static int netlink_bind(struct socket *sock, struct sockaddr *addr,
918 int addr_len)
919{
920 struct sock *sk = sock->sk;
921 struct net *net = sock_net(sk);
922 struct netlink_sock *nlk = nlk_sk(sk);
923 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
924 int err;
925 long unsigned int groups = nladdr->nl_groups;
926 bool bound;
927
928 if (addr_len < sizeof(struct sockaddr_nl))
929 return -EINVAL;
930
931 if (nladdr->nl_family != AF_NETLINK)
932 return -EINVAL;
933
934 /* Only superuser is allowed to listen multicasts */
935 if (groups) {
936 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
937 return -EPERM;
938 err = netlink_realloc_groups(sk);
939 if (err)
940 return err;
941 }
942
943 bound = nlk->bound;
944 if (bound) {
945 /* Ensure nlk->portid is up-to-date. */
946 smp_rmb();
947
948 if (nladdr->nl_pid != nlk->portid)
949 return -EINVAL;
950 }
951
952 if (nlk->netlink_bind && groups) {
953 int group;
954
955 for (group = 0; group < nlk->ngroups; group++) {
956 if (!test_bit(group, &groups))
957 continue;
958 err = nlk->netlink_bind(net, group + 1);
959 if (!err)
960 continue;
961 netlink_undo_bind(group, groups, sk);
962 return err;
963 }
964 }
965
966 /* No need for barriers here as we return to user-space without
967 * using any of the bound attributes.
968 */
969 if (!bound) {
970 err = nladdr->nl_pid ?
971 netlink_insert(sk, nladdr->nl_pid) :
972 netlink_autobind(sock);
973 if (err) {
974 netlink_undo_bind(nlk->ngroups, groups, sk);
975 return err;
976 }
977 }
978
979 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
980 return 0;
981
982 netlink_table_grab();
983 netlink_update_subscriptions(sk, nlk->subscriptions +
984 hweight32(groups) -
985 hweight32(nlk->groups[0]));
986 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
987 netlink_update_listeners(sk);
988 netlink_table_ungrab();
989
990 return 0;
991}
992
993static int netlink_connect(struct socket *sock, struct sockaddr *addr,
994 int alen, int flags)
995{
996 int err = 0;
997 struct sock *sk = sock->sk;
998 struct netlink_sock *nlk = nlk_sk(sk);
999 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1000
1001 if (alen < sizeof(addr->sa_family))
1002 return -EINVAL;
1003
1004 if (addr->sa_family == AF_UNSPEC) {
1005 sk->sk_state = NETLINK_UNCONNECTED;
1006 nlk->dst_portid = 0;
1007 nlk->dst_group = 0;
1008 return 0;
1009 }
1010 if (addr->sa_family != AF_NETLINK)
1011 return -EINVAL;
1012
1013 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1014 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1015 return -EPERM;
1016
1017 /* No need for barriers here as we return to user-space without
1018 * using any of the bound attributes.
1019 */
1020 if (!nlk->bound)
1021 err = netlink_autobind(sock);
1022
1023 if (err == 0) {
1024 sk->sk_state = NETLINK_CONNECTED;
1025 nlk->dst_portid = nladdr->nl_pid;
1026 nlk->dst_group = ffs(nladdr->nl_groups);
1027 }
1028
1029 return err;
1030}
1031
1032static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1033 int *addr_len, int peer)
1034{
1035 struct sock *sk = sock->sk;
1036 struct netlink_sock *nlk = nlk_sk(sk);
1037 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1038
1039 nladdr->nl_family = AF_NETLINK;
1040 nladdr->nl_pad = 0;
1041 *addr_len = sizeof(*nladdr);
1042
1043 if (peer) {
1044 nladdr->nl_pid = nlk->dst_portid;
1045 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1046 } else {
1047 nladdr->nl_pid = nlk->portid;
1048 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1049 }
1050 return 0;
1051}
1052
1053static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1054 unsigned long arg)
1055{
1056 /* try to hand this ioctl down to the NIC drivers.
1057 */
1058 return -ENOIOCTLCMD;
1059}
1060
1061static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1062{
1063 struct sock *sock;
1064 struct netlink_sock *nlk;
1065
1066 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1067 if (!sock)
1068 return ERR_PTR(-ECONNREFUSED);
1069
1070 /* Don't bother queuing skb if kernel socket has no input function */
1071 nlk = nlk_sk(sock);
1072 if (sock->sk_state == NETLINK_CONNECTED &&
1073 nlk->dst_portid != nlk_sk(ssk)->portid) {
1074 sock_put(sock);
1075 return ERR_PTR(-ECONNREFUSED);
1076 }
1077 return sock;
1078}
1079
1080struct sock *netlink_getsockbyfilp(struct file *filp)
1081{
1082 struct inode *inode = file_inode(filp);
1083 struct sock *sock;
1084
1085 if (!S_ISSOCK(inode->i_mode))
1086 return ERR_PTR(-ENOTSOCK);
1087
1088 sock = SOCKET_I(inode)->sk;
1089 if (sock->sk_family != AF_NETLINK)
1090 return ERR_PTR(-EINVAL);
1091
1092 sock_hold(sock);
1093 return sock;
1094}
1095
1096static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1097 int broadcast)
1098{
1099 struct sk_buff *skb;
1100 void *data;
1101
1102 if (size <= NLMSG_GOODSIZE || broadcast)
1103 return alloc_skb(size, GFP_KERNEL);
1104
1105 size = SKB_DATA_ALIGN(size) +
1106 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1107
1108 data = vmalloc(size);
1109 if (data == NULL)
1110 return NULL;
1111
1112 skb = __build_skb(data, size);
1113 if (skb == NULL)
1114 vfree(data);
1115 else
1116 skb->destructor = netlink_skb_destructor;
1117
1118 return skb;
1119}
1120
1121/*
1122 * Attach a skb to a netlink socket.
1123 * The caller must hold a reference to the destination socket. On error, the
1124 * reference is dropped. The skb is not send to the destination, just all
1125 * all error checks are performed and memory in the queue is reserved.
1126 * Return values:
1127 * < 0: error. skb freed, reference to sock dropped.
1128 * 0: continue
1129 * 1: repeat lookup - reference dropped while waiting for socket memory.
1130 */
1131int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1132 long *timeo, struct sock *ssk)
1133{
1134 struct netlink_sock *nlk;
1135
1136 nlk = nlk_sk(sk);
1137
1138 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1139 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1140 DECLARE_WAITQUEUE(wait, current);
1141 if (!*timeo) {
1142 if (!ssk || netlink_is_kernel(ssk))
1143 netlink_overrun(sk);
1144 sock_put(sk);
1145 kfree_skb(skb);
1146 return -EAGAIN;
1147 }
1148
1149 __set_current_state(TASK_INTERRUPTIBLE);
1150 add_wait_queue(&nlk->wait, &wait);
1151
1152 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1153 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1154 !sock_flag(sk, SOCK_DEAD))
1155 *timeo = schedule_timeout(*timeo);
1156
1157 __set_current_state(TASK_RUNNING);
1158 remove_wait_queue(&nlk->wait, &wait);
1159 sock_put(sk);
1160
1161 if (signal_pending(current)) {
1162 kfree_skb(skb);
1163 return sock_intr_errno(*timeo);
1164 }
1165 return 1;
1166 }
1167 netlink_skb_set_owner_r(skb, sk);
1168 return 0;
1169}
1170
1171static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1172{
1173 int len = skb->len;
1174
1175 netlink_deliver_tap(skb);
1176
1177 skb_queue_tail(&sk->sk_receive_queue, skb);
1178 sk->sk_data_ready(sk);
1179 return len;
1180}
1181
1182int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1183{
1184 int len = __netlink_sendskb(sk, skb);
1185
1186 sock_put(sk);
1187 return len;
1188}
1189
1190void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1191{
1192 kfree_skb(skb);
1193 sock_put(sk);
1194}
1195
1196static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1197{
1198 int delta;
1199
1200 WARN_ON(skb->sk != NULL);
1201 delta = skb->end - skb->tail;
1202 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1203 return skb;
1204
1205 if (skb_shared(skb)) {
1206 struct sk_buff *nskb = skb_clone(skb, allocation);
1207 if (!nskb)
1208 return skb;
1209 consume_skb(skb);
1210 skb = nskb;
1211 }
1212
1213 if (!pskb_expand_head(skb, 0, -delta, allocation))
1214 skb->truesize -= delta;
1215
1216 return skb;
1217}
1218
1219static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1220 struct sock *ssk)
1221{
1222 int ret;
1223 struct netlink_sock *nlk = nlk_sk(sk);
1224
1225 ret = -ECONNREFUSED;
1226 if (nlk->netlink_rcv != NULL) {
1227 ret = skb->len;
1228 netlink_skb_set_owner_r(skb, sk);
1229 NETLINK_CB(skb).sk = ssk;
1230 netlink_deliver_tap_kernel(sk, ssk, skb);
1231 nlk->netlink_rcv(skb);
1232 consume_skb(skb);
1233 } else {
1234 kfree_skb(skb);
1235 }
1236 sock_put(sk);
1237 return ret;
1238}
1239
1240int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1241 u32 portid, int nonblock)
1242{
1243 struct sock *sk;
1244 int err;
1245 long timeo;
1246
1247 skb = netlink_trim(skb, gfp_any());
1248
1249 timeo = sock_sndtimeo(ssk, nonblock);
1250retry:
1251 sk = netlink_getsockbyportid(ssk, portid);
1252 if (IS_ERR(sk)) {
1253 kfree_skb(skb);
1254 return PTR_ERR(sk);
1255 }
1256 if (netlink_is_kernel(sk))
1257 return netlink_unicast_kernel(sk, skb, ssk);
1258
1259 if (sk_filter(sk, skb)) {
1260 err = skb->len;
1261 kfree_skb(skb);
1262 sock_put(sk);
1263 return err;
1264 }
1265
1266 err = netlink_attachskb(sk, skb, &timeo, ssk);
1267 if (err == 1)
1268 goto retry;
1269 if (err)
1270 return err;
1271
1272 return netlink_sendskb(sk, skb);
1273}
1274EXPORT_SYMBOL(netlink_unicast);
1275
1276int netlink_has_listeners(struct sock *sk, unsigned int group)
1277{
1278 int res = 0;
1279 struct listeners *listeners;
1280
1281 BUG_ON(!netlink_is_kernel(sk));
1282
1283 rcu_read_lock();
1284 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1285
1286 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1287 res = test_bit(group - 1, listeners->masks);
1288
1289 rcu_read_unlock();
1290
1291 return res;
1292}
1293EXPORT_SYMBOL_GPL(netlink_has_listeners);
1294
1295static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1296{
1297 struct netlink_sock *nlk = nlk_sk(sk);
1298
1299 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1300 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1301 netlink_skb_set_owner_r(skb, sk);
1302 __netlink_sendskb(sk, skb);
1303 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1304 }
1305 return -1;
1306}
1307
1308struct netlink_broadcast_data {
1309 struct sock *exclude_sk;
1310 struct net *net;
1311 u32 portid;
1312 u32 group;
1313 int failure;
1314 int delivery_failure;
1315 int congested;
1316 int delivered;
1317 gfp_t allocation;
1318 struct sk_buff *skb, *skb2;
1319 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1320 void *tx_data;
1321};
1322
1323static void do_one_broadcast(struct sock *sk,
1324 struct netlink_broadcast_data *p)
1325{
1326 struct netlink_sock *nlk = nlk_sk(sk);
1327 int val;
1328
1329 if (p->exclude_sk == sk)
1330 return;
1331
1332 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1333 !test_bit(p->group - 1, nlk->groups))
1334 return;
1335
1336 if (!net_eq(sock_net(sk), p->net)) {
1337 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1338 return;
1339
1340 if (!peernet_has_id(sock_net(sk), p->net))
1341 return;
1342
1343 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1344 CAP_NET_BROADCAST))
1345 return;
1346 }
1347
1348 if (p->failure) {
1349 netlink_overrun(sk);
1350 return;
1351 }
1352
1353 sock_hold(sk);
1354 if (p->skb2 == NULL) {
1355 if (skb_shared(p->skb)) {
1356 p->skb2 = skb_clone(p->skb, p->allocation);
1357 } else {
1358 p->skb2 = skb_get(p->skb);
1359 /*
1360 * skb ownership may have been set when
1361 * delivered to a previous socket.
1362 */
1363 skb_orphan(p->skb2);
1364 }
1365 }
1366 if (p->skb2 == NULL) {
1367 netlink_overrun(sk);
1368 /* Clone failed. Notify ALL listeners. */
1369 p->failure = 1;
1370 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1371 p->delivery_failure = 1;
1372 goto out;
1373 }
1374 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1375 kfree_skb(p->skb2);
1376 p->skb2 = NULL;
1377 goto out;
1378 }
1379 if (sk_filter(sk, p->skb2)) {
1380 kfree_skb(p->skb2);
1381 p->skb2 = NULL;
1382 goto out;
1383 }
1384 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1385 NETLINK_CB(p->skb2).nsid_is_set = true;
1386 val = netlink_broadcast_deliver(sk, p->skb2);
1387 if (val < 0) {
1388 netlink_overrun(sk);
1389 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1390 p->delivery_failure = 1;
1391 } else {
1392 p->congested |= val;
1393 p->delivered = 1;
1394 p->skb2 = NULL;
1395 }
1396out:
1397 sock_put(sk);
1398}
1399
1400int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1401 u32 group, gfp_t allocation,
1402 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1403 void *filter_data)
1404{
1405 struct net *net = sock_net(ssk);
1406 struct netlink_broadcast_data info;
1407 struct sock *sk;
1408
1409 skb = netlink_trim(skb, allocation);
1410
1411 info.exclude_sk = ssk;
1412 info.net = net;
1413 info.portid = portid;
1414 info.group = group;
1415 info.failure = 0;
1416 info.delivery_failure = 0;
1417 info.congested = 0;
1418 info.delivered = 0;
1419 info.allocation = allocation;
1420 info.skb = skb;
1421 info.skb2 = NULL;
1422 info.tx_filter = filter;
1423 info.tx_data = filter_data;
1424
1425 /* While we sleep in clone, do not allow to change socket list */
1426
1427 netlink_lock_table();
1428
1429 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1430 do_one_broadcast(sk, &info);
1431
1432 consume_skb(skb);
1433
1434 netlink_unlock_table();
1435
1436 if (info.delivery_failure) {
1437 kfree_skb(info.skb2);
1438 return -ENOBUFS;
1439 }
1440 consume_skb(info.skb2);
1441
1442 if (info.delivered) {
1443 if (info.congested && gfpflags_allow_blocking(allocation))
1444 yield();
1445 return 0;
1446 }
1447 return -ESRCH;
1448}
1449EXPORT_SYMBOL(netlink_broadcast_filtered);
1450
1451int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1452 u32 group, gfp_t allocation)
1453{
1454 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1455 NULL, NULL);
1456}
1457EXPORT_SYMBOL(netlink_broadcast);
1458
1459struct netlink_set_err_data {
1460 struct sock *exclude_sk;
1461 u32 portid;
1462 u32 group;
1463 int code;
1464};
1465
1466static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1467{
1468 struct netlink_sock *nlk = nlk_sk(sk);
1469 int ret = 0;
1470
1471 if (sk == p->exclude_sk)
1472 goto out;
1473
1474 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1475 goto out;
1476
1477 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1478 !test_bit(p->group - 1, nlk->groups))
1479 goto out;
1480
1481 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1482 ret = 1;
1483 goto out;
1484 }
1485
1486 sk->sk_err = p->code;
1487 sk->sk_error_report(sk);
1488out:
1489 return ret;
1490}
1491
1492/**
1493 * netlink_set_err - report error to broadcast listeners
1494 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1495 * @portid: the PORTID of a process that we want to skip (if any)
1496 * @group: the broadcast group that will notice the error
1497 * @code: error code, must be negative (as usual in kernelspace)
1498 *
1499 * This function returns the number of broadcast listeners that have set the
1500 * NETLINK_NO_ENOBUFS socket option.
1501 */
1502int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1503{
1504 struct netlink_set_err_data info;
1505 struct sock *sk;
1506 int ret = 0;
1507
1508 info.exclude_sk = ssk;
1509 info.portid = portid;
1510 info.group = group;
1511 /* sk->sk_err wants a positive error value */
1512 info.code = -code;
1513
1514 read_lock(&nl_table_lock);
1515
1516 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1517 ret += do_one_set_err(sk, &info);
1518
1519 read_unlock(&nl_table_lock);
1520 return ret;
1521}
1522EXPORT_SYMBOL(netlink_set_err);
1523
1524/* must be called with netlink table grabbed */
1525static void netlink_update_socket_mc(struct netlink_sock *nlk,
1526 unsigned int group,
1527 int is_new)
1528{
1529 int old, new = !!is_new, subscriptions;
1530
1531 old = test_bit(group - 1, nlk->groups);
1532 subscriptions = nlk->subscriptions - old + new;
1533 if (new)
1534 __set_bit(group - 1, nlk->groups);
1535 else
1536 __clear_bit(group - 1, nlk->groups);
1537 netlink_update_subscriptions(&nlk->sk, subscriptions);
1538 netlink_update_listeners(&nlk->sk);
1539}
1540
1541static int netlink_setsockopt(struct socket *sock, int level, int optname,
1542 char __user *optval, unsigned int optlen)
1543{
1544 struct sock *sk = sock->sk;
1545 struct netlink_sock *nlk = nlk_sk(sk);
1546 unsigned int val = 0;
1547 int err;
1548
1549 if (level != SOL_NETLINK)
1550 return -ENOPROTOOPT;
1551
1552 if (optlen >= sizeof(int) &&
1553 get_user(val, (unsigned int __user *)optval))
1554 return -EFAULT;
1555
1556 switch (optname) {
1557 case NETLINK_PKTINFO:
1558 if (val)
1559 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1560 else
1561 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1562 err = 0;
1563 break;
1564 case NETLINK_ADD_MEMBERSHIP:
1565 case NETLINK_DROP_MEMBERSHIP: {
1566 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1567 return -EPERM;
1568 err = netlink_realloc_groups(sk);
1569 if (err)
1570 return err;
1571 if (!val || val - 1 >= nlk->ngroups)
1572 return -EINVAL;
1573 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1574 err = nlk->netlink_bind(sock_net(sk), val);
1575 if (err)
1576 return err;
1577 }
1578 netlink_table_grab();
1579 netlink_update_socket_mc(nlk, val,
1580 optname == NETLINK_ADD_MEMBERSHIP);
1581 netlink_table_ungrab();
1582 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1583 nlk->netlink_unbind(sock_net(sk), val);
1584
1585 err = 0;
1586 break;
1587 }
1588 case NETLINK_BROADCAST_ERROR:
1589 if (val)
1590 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1591 else
1592 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1593 err = 0;
1594 break;
1595 case NETLINK_NO_ENOBUFS:
1596 if (val) {
1597 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1598 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1599 wake_up_interruptible(&nlk->wait);
1600 } else {
1601 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1602 }
1603 err = 0;
1604 break;
1605 case NETLINK_LISTEN_ALL_NSID:
1606 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1607 return -EPERM;
1608
1609 if (val)
1610 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1611 else
1612 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1613 err = 0;
1614 break;
1615 case NETLINK_CAP_ACK:
1616 if (val)
1617 nlk->flags |= NETLINK_F_CAP_ACK;
1618 else
1619 nlk->flags &= ~NETLINK_F_CAP_ACK;
1620 err = 0;
1621 break;
1622 default:
1623 err = -ENOPROTOOPT;
1624 }
1625 return err;
1626}
1627
1628static int netlink_getsockopt(struct socket *sock, int level, int optname,
1629 char __user *optval, int __user *optlen)
1630{
1631 struct sock *sk = sock->sk;
1632 struct netlink_sock *nlk = nlk_sk(sk);
1633 int len, val, err;
1634
1635 if (level != SOL_NETLINK)
1636 return -ENOPROTOOPT;
1637
1638 if (get_user(len, optlen))
1639 return -EFAULT;
1640 if (len < 0)
1641 return -EINVAL;
1642
1643 switch (optname) {
1644 case NETLINK_PKTINFO:
1645 if (len < sizeof(int))
1646 return -EINVAL;
1647 len = sizeof(int);
1648 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1649 if (put_user(len, optlen) ||
1650 put_user(val, optval))
1651 return -EFAULT;
1652 err = 0;
1653 break;
1654 case NETLINK_BROADCAST_ERROR:
1655 if (len < sizeof(int))
1656 return -EINVAL;
1657 len = sizeof(int);
1658 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1659 if (put_user(len, optlen) ||
1660 put_user(val, optval))
1661 return -EFAULT;
1662 err = 0;
1663 break;
1664 case NETLINK_NO_ENOBUFS:
1665 if (len < sizeof(int))
1666 return -EINVAL;
1667 len = sizeof(int);
1668 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1669 if (put_user(len, optlen) ||
1670 put_user(val, optval))
1671 return -EFAULT;
1672 err = 0;
1673 break;
1674 case NETLINK_LIST_MEMBERSHIPS: {
1675 int pos, idx, shift;
1676
1677 err = 0;
1678 netlink_lock_table();
1679 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1680 if (len - pos < sizeof(u32))
1681 break;
1682
1683 idx = pos / sizeof(unsigned long);
1684 shift = (pos % sizeof(unsigned long)) * 8;
1685 if (put_user((u32)(nlk->groups[idx] >> shift),
1686 (u32 __user *)(optval + pos))) {
1687 err = -EFAULT;
1688 break;
1689 }
1690 }
1691 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1692 err = -EFAULT;
1693 netlink_unlock_table();
1694 break;
1695 }
1696 case NETLINK_CAP_ACK:
1697 if (len < sizeof(int))
1698 return -EINVAL;
1699 len = sizeof(int);
1700 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1701 if (put_user(len, optlen) ||
1702 put_user(val, optval))
1703 return -EFAULT;
1704 err = 0;
1705 break;
1706 default:
1707 err = -ENOPROTOOPT;
1708 }
1709 return err;
1710}
1711
1712static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1713{
1714 struct nl_pktinfo info;
1715
1716 info.group = NETLINK_CB(skb).dst_group;
1717 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1718}
1719
1720static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1721 struct sk_buff *skb)
1722{
1723 if (!NETLINK_CB(skb).nsid_is_set)
1724 return;
1725
1726 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1727 &NETLINK_CB(skb).nsid);
1728}
1729
1730static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1731{
1732 struct sock *sk = sock->sk;
1733 struct netlink_sock *nlk = nlk_sk(sk);
1734 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1735 u32 dst_portid;
1736 u32 dst_group;
1737 struct sk_buff *skb;
1738 int err;
1739 struct scm_cookie scm;
1740 u32 netlink_skb_flags = 0;
1741
1742 if (msg->msg_flags&MSG_OOB)
1743 return -EOPNOTSUPP;
1744
1745 err = scm_send(sock, msg, &scm, true);
1746 if (err < 0)
1747 return err;
1748
1749 if (msg->msg_namelen) {
1750 err = -EINVAL;
1751 if (addr->nl_family != AF_NETLINK)
1752 goto out;
1753 dst_portid = addr->nl_pid;
1754 dst_group = ffs(addr->nl_groups);
1755 err = -EPERM;
1756 if ((dst_group || dst_portid) &&
1757 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1758 goto out;
1759 netlink_skb_flags |= NETLINK_SKB_DST;
1760 } else {
1761 dst_portid = nlk->dst_portid;
1762 dst_group = nlk->dst_group;
1763 }
1764
1765 if (!nlk->bound) {
1766 err = netlink_autobind(sock);
1767 if (err)
1768 goto out;
1769 } else {
1770 /* Ensure nlk is hashed and visible. */
1771 smp_rmb();
1772 }
1773
1774 err = -EMSGSIZE;
1775 if (len > sk->sk_sndbuf - 32)
1776 goto out;
1777 err = -ENOBUFS;
1778 skb = netlink_alloc_large_skb(len, dst_group);
1779 if (skb == NULL)
1780 goto out;
1781
1782 NETLINK_CB(skb).portid = nlk->portid;
1783 NETLINK_CB(skb).dst_group = dst_group;
1784 NETLINK_CB(skb).creds = scm.creds;
1785 NETLINK_CB(skb).flags = netlink_skb_flags;
1786
1787 err = -EFAULT;
1788 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1789 kfree_skb(skb);
1790 goto out;
1791 }
1792
1793 err = security_netlink_send(sk, skb);
1794 if (err) {
1795 kfree_skb(skb);
1796 goto out;
1797 }
1798
1799 if (dst_group) {
1800 atomic_inc(&skb->users);
1801 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1802 }
1803 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1804
1805out:
1806 scm_destroy(&scm);
1807 return err;
1808}
1809
1810static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1811 int flags)
1812{
1813 struct scm_cookie scm;
1814 struct sock *sk = sock->sk;
1815 struct netlink_sock *nlk = nlk_sk(sk);
1816 int noblock = flags&MSG_DONTWAIT;
1817 size_t copied;
1818 struct sk_buff *skb, *data_skb;
1819 int err, ret;
1820
1821 if (flags&MSG_OOB)
1822 return -EOPNOTSUPP;
1823
1824 copied = 0;
1825
1826 skb = skb_recv_datagram(sk, flags, noblock, &err);
1827 if (skb == NULL)
1828 goto out;
1829
1830 data_skb = skb;
1831
1832#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1833 if (unlikely(skb_shinfo(skb)->frag_list)) {
1834 /*
1835 * If this skb has a frag_list, then here that means that we
1836 * will have to use the frag_list skb's data for compat tasks
1837 * and the regular skb's data for normal (non-compat) tasks.
1838 *
1839 * If we need to send the compat skb, assign it to the
1840 * 'data_skb' variable so that it will be used below for data
1841 * copying. We keep 'skb' for everything else, including
1842 * freeing both later.
1843 */
1844 if (flags & MSG_CMSG_COMPAT)
1845 data_skb = skb_shinfo(skb)->frag_list;
1846 }
1847#endif
1848
1849 /* Record the max length of recvmsg() calls for future allocations */
1850 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1851 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1852 SKB_WITH_OVERHEAD(32768));
1853
1854 copied = data_skb->len;
1855 if (len < copied) {
1856 msg->msg_flags |= MSG_TRUNC;
1857 copied = len;
1858 }
1859
1860 skb_reset_transport_header(data_skb);
1861 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1862
1863 if (msg->msg_name) {
1864 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1865 addr->nl_family = AF_NETLINK;
1866 addr->nl_pad = 0;
1867 addr->nl_pid = NETLINK_CB(skb).portid;
1868 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1869 msg->msg_namelen = sizeof(*addr);
1870 }
1871
1872 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1873 netlink_cmsg_recv_pktinfo(msg, skb);
1874 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1875 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1876
1877 memset(&scm, 0, sizeof(scm));
1878 scm.creds = *NETLINK_CREDS(skb);
1879 if (flags & MSG_TRUNC)
1880 copied = data_skb->len;
1881
1882 skb_free_datagram(sk, skb);
1883
1884 if (nlk->cb_running &&
1885 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1886 ret = netlink_dump(sk);
1887 if (ret) {
1888 sk->sk_err = -ret;
1889 sk->sk_error_report(sk);
1890 }
1891 }
1892
1893 scm_recv(sock, msg, &scm, flags);
1894out:
1895 netlink_rcv_wake(sk);
1896 return err ? : copied;
1897}
1898
1899static void netlink_data_ready(struct sock *sk)
1900{
1901 BUG();
1902}
1903
1904/*
1905 * We export these functions to other modules. They provide a
1906 * complete set of kernel non-blocking support for message
1907 * queueing.
1908 */
1909
1910struct sock *
1911__netlink_kernel_create(struct net *net, int unit, struct module *module,
1912 struct netlink_kernel_cfg *cfg)
1913{
1914 struct socket *sock;
1915 struct sock *sk;
1916 struct netlink_sock *nlk;
1917 struct listeners *listeners = NULL;
1918 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
1919 unsigned int groups;
1920
1921 BUG_ON(!nl_table);
1922
1923 if (unit < 0 || unit >= MAX_LINKS)
1924 return NULL;
1925
1926 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1927 return NULL;
1928
1929 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
1930 goto out_sock_release_nosk;
1931
1932 sk = sock->sk;
1933
1934 if (!cfg || cfg->groups < 32)
1935 groups = 32;
1936 else
1937 groups = cfg->groups;
1938
1939 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1940 if (!listeners)
1941 goto out_sock_release;
1942
1943 sk->sk_data_ready = netlink_data_ready;
1944 if (cfg && cfg->input)
1945 nlk_sk(sk)->netlink_rcv = cfg->input;
1946
1947 if (netlink_insert(sk, 0))
1948 goto out_sock_release;
1949
1950 nlk = nlk_sk(sk);
1951 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
1952
1953 netlink_table_grab();
1954 if (!nl_table[unit].registered) {
1955 nl_table[unit].groups = groups;
1956 rcu_assign_pointer(nl_table[unit].listeners, listeners);
1957 nl_table[unit].cb_mutex = cb_mutex;
1958 nl_table[unit].module = module;
1959 if (cfg) {
1960 nl_table[unit].bind = cfg->bind;
1961 nl_table[unit].unbind = cfg->unbind;
1962 nl_table[unit].flags = cfg->flags;
1963 if (cfg->compare)
1964 nl_table[unit].compare = cfg->compare;
1965 }
1966 nl_table[unit].registered = 1;
1967 } else {
1968 kfree(listeners);
1969 nl_table[unit].registered++;
1970 }
1971 netlink_table_ungrab();
1972 return sk;
1973
1974out_sock_release:
1975 kfree(listeners);
1976 netlink_kernel_release(sk);
1977 return NULL;
1978
1979out_sock_release_nosk:
1980 sock_release(sock);
1981 return NULL;
1982}
1983EXPORT_SYMBOL(__netlink_kernel_create);
1984
1985void
1986netlink_kernel_release(struct sock *sk)
1987{
1988 if (sk == NULL || sk->sk_socket == NULL)
1989 return;
1990
1991 sock_release(sk->sk_socket);
1992}
1993EXPORT_SYMBOL(netlink_kernel_release);
1994
1995int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1996{
1997 struct listeners *new, *old;
1998 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1999
2000 if (groups < 32)
2001 groups = 32;
2002
2003 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2004 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2005 if (!new)
2006 return -ENOMEM;
2007 old = nl_deref_protected(tbl->listeners);
2008 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2009 rcu_assign_pointer(tbl->listeners, new);
2010
2011 kfree_rcu(old, rcu);
2012 }
2013 tbl->groups = groups;
2014
2015 return 0;
2016}
2017
2018/**
2019 * netlink_change_ngroups - change number of multicast groups
2020 *
2021 * This changes the number of multicast groups that are available
2022 * on a certain netlink family. Note that it is not possible to
2023 * change the number of groups to below 32. Also note that it does
2024 * not implicitly call netlink_clear_multicast_users() when the
2025 * number of groups is reduced.
2026 *
2027 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2028 * @groups: The new number of groups.
2029 */
2030int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2031{
2032 int err;
2033
2034 netlink_table_grab();
2035 err = __netlink_change_ngroups(sk, groups);
2036 netlink_table_ungrab();
2037
2038 return err;
2039}
2040
2041void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2042{
2043 struct sock *sk;
2044 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2045
2046 sk_for_each_bound(sk, &tbl->mc_list)
2047 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2048}
2049
2050struct nlmsghdr *
2051__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2052{
2053 struct nlmsghdr *nlh;
2054 int size = nlmsg_msg_size(len);
2055
2056 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2057 nlh->nlmsg_type = type;
2058 nlh->nlmsg_len = size;
2059 nlh->nlmsg_flags = flags;
2060 nlh->nlmsg_pid = portid;
2061 nlh->nlmsg_seq = seq;
2062 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2063 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2064 return nlh;
2065}
2066EXPORT_SYMBOL(__nlmsg_put);
2067
2068/*
2069 * It looks a bit ugly.
2070 * It would be better to create kernel thread.
2071 */
2072
2073static int netlink_dump(struct sock *sk)
2074{
2075 struct netlink_sock *nlk = nlk_sk(sk);
2076 struct netlink_callback *cb;
2077 struct sk_buff *skb = NULL;
2078 struct nlmsghdr *nlh;
2079 struct module *module;
2080 int len, err = -ENOBUFS;
2081 int alloc_min_size;
2082 int alloc_size;
2083
2084 mutex_lock(nlk->cb_mutex);
2085 if (!nlk->cb_running) {
2086 err = -EINVAL;
2087 goto errout_skb;
2088 }
2089
2090 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2091 goto errout_skb;
2092
2093 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2094 * required, but it makes sense to _attempt_ a 16K bytes allocation
2095 * to reduce number of system calls on dump operations, if user
2096 * ever provided a big enough buffer.
2097 */
2098 cb = &nlk->cb;
2099 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2100
2101 if (alloc_min_size < nlk->max_recvmsg_len) {
2102 alloc_size = nlk->max_recvmsg_len;
2103 skb = alloc_skb(alloc_size,
2104 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2105 __GFP_NOWARN | __GFP_NORETRY);
2106 }
2107 if (!skb) {
2108 alloc_size = alloc_min_size;
2109 skb = alloc_skb(alloc_size, GFP_KERNEL);
2110 }
2111 if (!skb)
2112 goto errout_skb;
2113
2114 /* Trim skb to allocated size. User is expected to provide buffer as
2115 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2116 * netlink_recvmsg())). dump will pack as many smaller messages as
2117 * could fit within the allocated skb. skb is typically allocated
2118 * with larger space than required (could be as much as near 2x the
2119 * requested size with align to next power of 2 approach). Allowing
2120 * dump to use the excess space makes it difficult for a user to have a
2121 * reasonable static buffer based on the expected largest dump of a
2122 * single netdev. The outcome is MSG_TRUNC error.
2123 */
2124 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2125 netlink_skb_set_owner_r(skb, sk);
2126
2127 len = cb->dump(skb, cb);
2128
2129 if (len > 0) {
2130 mutex_unlock(nlk->cb_mutex);
2131
2132 if (sk_filter(sk, skb))
2133 kfree_skb(skb);
2134 else
2135 __netlink_sendskb(sk, skb);
2136 return 0;
2137 }
2138
2139 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2140 if (!nlh)
2141 goto errout_skb;
2142
2143 nl_dump_check_consistent(cb, nlh);
2144
2145 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2146
2147 if (sk_filter(sk, skb))
2148 kfree_skb(skb);
2149 else
2150 __netlink_sendskb(sk, skb);
2151
2152 if (cb->done)
2153 cb->done(cb);
2154
2155 nlk->cb_running = false;
2156 module = cb->module;
2157 skb = cb->skb;
2158 mutex_unlock(nlk->cb_mutex);
2159 module_put(module);
2160 consume_skb(skb);
2161 return 0;
2162
2163errout_skb:
2164 mutex_unlock(nlk->cb_mutex);
2165 kfree_skb(skb);
2166 return err;
2167}
2168
2169int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2170 const struct nlmsghdr *nlh,
2171 struct netlink_dump_control *control)
2172{
2173 struct netlink_callback *cb;
2174 struct sock *sk;
2175 struct netlink_sock *nlk;
2176 int ret;
2177
2178 atomic_inc(&skb->users);
2179
2180 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2181 if (sk == NULL) {
2182 ret = -ECONNREFUSED;
2183 goto error_free;
2184 }
2185
2186 nlk = nlk_sk(sk);
2187 mutex_lock(nlk->cb_mutex);
2188 /* A dump is in progress... */
2189 if (nlk->cb_running) {
2190 ret = -EBUSY;
2191 goto error_unlock;
2192 }
2193 /* add reference of module which cb->dump belongs to */
2194 if (!try_module_get(control->module)) {
2195 ret = -EPROTONOSUPPORT;
2196 goto error_unlock;
2197 }
2198
2199 cb = &nlk->cb;
2200 memset(cb, 0, sizeof(*cb));
2201 cb->start = control->start;
2202 cb->dump = control->dump;
2203 cb->done = control->done;
2204 cb->nlh = nlh;
2205 cb->data = control->data;
2206 cb->module = control->module;
2207 cb->min_dump_alloc = control->min_dump_alloc;
2208 cb->skb = skb;
2209
2210 nlk->cb_running = true;
2211
2212 mutex_unlock(nlk->cb_mutex);
2213
2214 if (cb->start)
2215 cb->start(cb);
2216
2217 ret = netlink_dump(sk);
2218 sock_put(sk);
2219
2220 if (ret)
2221 return ret;
2222
2223 /* We successfully started a dump, by returning -EINTR we
2224 * signal not to send ACK even if it was requested.
2225 */
2226 return -EINTR;
2227
2228error_unlock:
2229 sock_put(sk);
2230 mutex_unlock(nlk->cb_mutex);
2231error_free:
2232 kfree_skb(skb);
2233 return ret;
2234}
2235EXPORT_SYMBOL(__netlink_dump_start);
2236
2237void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2238{
2239 struct sk_buff *skb;
2240 struct nlmsghdr *rep;
2241 struct nlmsgerr *errmsg;
2242 size_t payload = sizeof(*errmsg);
2243 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2244
2245 /* Error messages get the original request appened, unless the user
2246 * requests to cap the error message.
2247 */
2248 if (!(nlk->flags & NETLINK_F_CAP_ACK) && err)
2249 payload += nlmsg_len(nlh);
2250
2251 skb = nlmsg_new(payload, GFP_KERNEL);
2252 if (!skb) {
2253 struct sock *sk;
2254
2255 sk = netlink_lookup(sock_net(in_skb->sk),
2256 in_skb->sk->sk_protocol,
2257 NETLINK_CB(in_skb).portid);
2258 if (sk) {
2259 sk->sk_err = ENOBUFS;
2260 sk->sk_error_report(sk);
2261 sock_put(sk);
2262 }
2263 return;
2264 }
2265
2266 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2267 NLMSG_ERROR, payload, 0);
2268 errmsg = nlmsg_data(rep);
2269 errmsg->error = err;
2270 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2271 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2272}
2273EXPORT_SYMBOL(netlink_ack);
2274
2275int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2276 struct nlmsghdr *))
2277{
2278 struct nlmsghdr *nlh;
2279 int err;
2280
2281 while (skb->len >= nlmsg_total_size(0)) {
2282 int msglen;
2283
2284 nlh = nlmsg_hdr(skb);
2285 err = 0;
2286
2287 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2288 return 0;
2289
2290 /* Only requests are handled by the kernel */
2291 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2292 goto ack;
2293
2294 /* Skip control messages */
2295 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2296 goto ack;
2297
2298 err = cb(skb, nlh);
2299 if (err == -EINTR)
2300 goto skip;
2301
2302ack:
2303 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2304 netlink_ack(skb, nlh, err);
2305
2306skip:
2307 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2308 if (msglen > skb->len)
2309 msglen = skb->len;
2310 skb_pull(skb, msglen);
2311 }
2312
2313 return 0;
2314}
2315EXPORT_SYMBOL(netlink_rcv_skb);
2316
2317/**
2318 * nlmsg_notify - send a notification netlink message
2319 * @sk: netlink socket to use
2320 * @skb: notification message
2321 * @portid: destination netlink portid for reports or 0
2322 * @group: destination multicast group or 0
2323 * @report: 1 to report back, 0 to disable
2324 * @flags: allocation flags
2325 */
2326int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2327 unsigned int group, int report, gfp_t flags)
2328{
2329 int err = 0;
2330
2331 if (group) {
2332 int exclude_portid = 0;
2333
2334 if (report) {
2335 atomic_inc(&skb->users);
2336 exclude_portid = portid;
2337 }
2338
2339 /* errors reported via destination sk->sk_err, but propagate
2340 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2341 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2342 }
2343
2344 if (report) {
2345 int err2;
2346
2347 err2 = nlmsg_unicast(sk, skb, portid);
2348 if (!err || err == -ESRCH)
2349 err = err2;
2350 }
2351
2352 return err;
2353}
2354EXPORT_SYMBOL(nlmsg_notify);
2355
2356#ifdef CONFIG_PROC_FS
2357struct nl_seq_iter {
2358 struct seq_net_private p;
2359 struct rhashtable_iter hti;
2360 int link;
2361};
2362
2363static int netlink_walk_start(struct nl_seq_iter *iter)
2364{
2365 int err;
2366
2367 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti,
2368 GFP_KERNEL);
2369 if (err) {
2370 iter->link = MAX_LINKS;
2371 return err;
2372 }
2373
2374 err = rhashtable_walk_start(&iter->hti);
2375 return err == -EAGAIN ? 0 : err;
2376}
2377
2378static void netlink_walk_stop(struct nl_seq_iter *iter)
2379{
2380 rhashtable_walk_stop(&iter->hti);
2381 rhashtable_walk_exit(&iter->hti);
2382}
2383
2384static void *__netlink_seq_next(struct seq_file *seq)
2385{
2386 struct nl_seq_iter *iter = seq->private;
2387 struct netlink_sock *nlk;
2388
2389 do {
2390 for (;;) {
2391 int err;
2392
2393 nlk = rhashtable_walk_next(&iter->hti);
2394
2395 if (IS_ERR(nlk)) {
2396 if (PTR_ERR(nlk) == -EAGAIN)
2397 continue;
2398
2399 return nlk;
2400 }
2401
2402 if (nlk)
2403 break;
2404
2405 netlink_walk_stop(iter);
2406 if (++iter->link >= MAX_LINKS)
2407 return NULL;
2408
2409 err = netlink_walk_start(iter);
2410 if (err)
2411 return ERR_PTR(err);
2412 }
2413 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2414
2415 return nlk;
2416}
2417
2418static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2419{
2420 struct nl_seq_iter *iter = seq->private;
2421 void *obj = SEQ_START_TOKEN;
2422 loff_t pos;
2423 int err;
2424
2425 iter->link = 0;
2426
2427 err = netlink_walk_start(iter);
2428 if (err)
2429 return ERR_PTR(err);
2430
2431 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2432 obj = __netlink_seq_next(seq);
2433
2434 return obj;
2435}
2436
2437static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2438{
2439 ++*pos;
2440 return __netlink_seq_next(seq);
2441}
2442
2443static void netlink_seq_stop(struct seq_file *seq, void *v)
2444{
2445 struct nl_seq_iter *iter = seq->private;
2446
2447 if (iter->link >= MAX_LINKS)
2448 return;
2449
2450 netlink_walk_stop(iter);
2451}
2452
2453
2454static int netlink_seq_show(struct seq_file *seq, void *v)
2455{
2456 if (v == SEQ_START_TOKEN) {
2457 seq_puts(seq,
2458 "sk Eth Pid Groups "
2459 "Rmem Wmem Dump Locks Drops Inode\n");
2460 } else {
2461 struct sock *s = v;
2462 struct netlink_sock *nlk = nlk_sk(s);
2463
2464 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2465 s,
2466 s->sk_protocol,
2467 nlk->portid,
2468 nlk->groups ? (u32)nlk->groups[0] : 0,
2469 sk_rmem_alloc_get(s),
2470 sk_wmem_alloc_get(s),
2471 nlk->cb_running,
2472 atomic_read(&s->sk_refcnt),
2473 atomic_read(&s->sk_drops),
2474 sock_i_ino(s)
2475 );
2476
2477 }
2478 return 0;
2479}
2480
2481static const struct seq_operations netlink_seq_ops = {
2482 .start = netlink_seq_start,
2483 .next = netlink_seq_next,
2484 .stop = netlink_seq_stop,
2485 .show = netlink_seq_show,
2486};
2487
2488
2489static int netlink_seq_open(struct inode *inode, struct file *file)
2490{
2491 return seq_open_net(inode, file, &netlink_seq_ops,
2492 sizeof(struct nl_seq_iter));
2493}
2494
2495static const struct file_operations netlink_seq_fops = {
2496 .owner = THIS_MODULE,
2497 .open = netlink_seq_open,
2498 .read = seq_read,
2499 .llseek = seq_lseek,
2500 .release = seq_release_net,
2501};
2502
2503#endif
2504
2505int netlink_register_notifier(struct notifier_block *nb)
2506{
2507 return blocking_notifier_chain_register(&netlink_chain, nb);
2508}
2509EXPORT_SYMBOL(netlink_register_notifier);
2510
2511int netlink_unregister_notifier(struct notifier_block *nb)
2512{
2513 return blocking_notifier_chain_unregister(&netlink_chain, nb);
2514}
2515EXPORT_SYMBOL(netlink_unregister_notifier);
2516
2517static const struct proto_ops netlink_ops = {
2518 .family = PF_NETLINK,
2519 .owner = THIS_MODULE,
2520 .release = netlink_release,
2521 .bind = netlink_bind,
2522 .connect = netlink_connect,
2523 .socketpair = sock_no_socketpair,
2524 .accept = sock_no_accept,
2525 .getname = netlink_getname,
2526 .poll = datagram_poll,
2527 .ioctl = netlink_ioctl,
2528 .listen = sock_no_listen,
2529 .shutdown = sock_no_shutdown,
2530 .setsockopt = netlink_setsockopt,
2531 .getsockopt = netlink_getsockopt,
2532 .sendmsg = netlink_sendmsg,
2533 .recvmsg = netlink_recvmsg,
2534 .mmap = sock_no_mmap,
2535 .sendpage = sock_no_sendpage,
2536};
2537
2538static const struct net_proto_family netlink_family_ops = {
2539 .family = PF_NETLINK,
2540 .create = netlink_create,
2541 .owner = THIS_MODULE, /* for consistency 8) */
2542};
2543
2544static int __net_init netlink_net_init(struct net *net)
2545{
2546#ifdef CONFIG_PROC_FS
2547 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
2548 return -ENOMEM;
2549#endif
2550 return 0;
2551}
2552
2553static void __net_exit netlink_net_exit(struct net *net)
2554{
2555#ifdef CONFIG_PROC_FS
2556 remove_proc_entry("netlink", net->proc_net);
2557#endif
2558}
2559
2560static void __init netlink_add_usersock_entry(void)
2561{
2562 struct listeners *listeners;
2563 int groups = 32;
2564
2565 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2566 if (!listeners)
2567 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2568
2569 netlink_table_grab();
2570
2571 nl_table[NETLINK_USERSOCK].groups = groups;
2572 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2573 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2574 nl_table[NETLINK_USERSOCK].registered = 1;
2575 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2576
2577 netlink_table_ungrab();
2578}
2579
2580static struct pernet_operations __net_initdata netlink_net_ops = {
2581 .init = netlink_net_init,
2582 .exit = netlink_net_exit,
2583};
2584
2585static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2586{
2587 const struct netlink_sock *nlk = data;
2588 struct netlink_compare_arg arg;
2589
2590 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2591 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2592}
2593
2594static const struct rhashtable_params netlink_rhashtable_params = {
2595 .head_offset = offsetof(struct netlink_sock, node),
2596 .key_len = netlink_compare_arg_len,
2597 .obj_hashfn = netlink_hash,
2598 .obj_cmpfn = netlink_compare,
2599 .automatic_shrinking = true,
2600};
2601
2602static int __init netlink_proto_init(void)
2603{
2604 int i;
2605 int err = proto_register(&netlink_proto, 0);
2606
2607 if (err != 0)
2608 goto out;
2609
2610 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2611
2612 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2613 if (!nl_table)
2614 goto panic;
2615
2616 for (i = 0; i < MAX_LINKS; i++) {
2617 if (rhashtable_init(&nl_table[i].hash,
2618 &netlink_rhashtable_params) < 0) {
2619 while (--i > 0)
2620 rhashtable_destroy(&nl_table[i].hash);
2621 kfree(nl_table);
2622 goto panic;
2623 }
2624 }
2625
2626 INIT_LIST_HEAD(&netlink_tap_all);
2627
2628 netlink_add_usersock_entry();
2629
2630 sock_register(&netlink_family_ops);
2631 register_pernet_subsys(&netlink_net_ops);
2632 /* The netlink device handler may be needed early. */
2633 rtnetlink_init();
2634out:
2635 return err;
2636panic:
2637 panic("netlink_init: Cannot allocate nl_table\n");
2638}
2639
2640core_initcall(netlink_proto_init);