Loading...
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 <asm/uaccess.h>
44#include <linux/skbuff.h>
45#include <linux/netdevice.h>
46#include <linux/rtnetlink.h>
47#include <linux/proc_fs.h>
48#include <linux/seq_file.h>
49#include <linux/notifier.h>
50#include <linux/security.h>
51#include <linux/jhash.h>
52#include <linux/jiffies.h>
53#include <linux/random.h>
54#include <linux/bitops.h>
55#include <linux/mm.h>
56#include <linux/types.h>
57#include <linux/audit.h>
58#include <linux/mutex.h>
59#include <linux/vmalloc.h>
60#include <linux/if_arp.h>
61#include <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 ATOMIC_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
333 module_put(nlk->cb.module);
334 kfree_skb(nlk->cb.skb);
335 }
336
337 skb_queue_purge(&sk->sk_receive_queue);
338
339 if (!sock_flag(sk, SOCK_DEAD)) {
340 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
341 return;
342 }
343
344 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
345 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
346 WARN_ON(nlk_sk(sk)->groups);
347}
348
349/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
350 * SMP. Look, when several writers sleep and reader wakes them up, all but one
351 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
352 * this, _but_ remember, it adds useless work on UP machines.
353 */
354
355void netlink_table_grab(void)
356 __acquires(nl_table_lock)
357{
358 might_sleep();
359
360 write_lock_irq(&nl_table_lock);
361
362 if (atomic_read(&nl_table_users)) {
363 DECLARE_WAITQUEUE(wait, current);
364
365 add_wait_queue_exclusive(&nl_table_wait, &wait);
366 for (;;) {
367 set_current_state(TASK_UNINTERRUPTIBLE);
368 if (atomic_read(&nl_table_users) == 0)
369 break;
370 write_unlock_irq(&nl_table_lock);
371 schedule();
372 write_lock_irq(&nl_table_lock);
373 }
374
375 __set_current_state(TASK_RUNNING);
376 remove_wait_queue(&nl_table_wait, &wait);
377 }
378}
379
380void netlink_table_ungrab(void)
381 __releases(nl_table_lock)
382{
383 write_unlock_irq(&nl_table_lock);
384 wake_up(&nl_table_wait);
385}
386
387static inline void
388netlink_lock_table(void)
389{
390 /* read_lock() synchronizes us to netlink_table_grab */
391
392 read_lock(&nl_table_lock);
393 atomic_inc(&nl_table_users);
394 read_unlock(&nl_table_lock);
395}
396
397static inline void
398netlink_unlock_table(void)
399{
400 if (atomic_dec_and_test(&nl_table_users))
401 wake_up(&nl_table_wait);
402}
403
404struct netlink_compare_arg
405{
406 possible_net_t pnet;
407 u32 portid;
408};
409
410/* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
411#define netlink_compare_arg_len \
412 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
413
414static inline int netlink_compare(struct rhashtable_compare_arg *arg,
415 const void *ptr)
416{
417 const struct netlink_compare_arg *x = arg->key;
418 const struct netlink_sock *nlk = ptr;
419
420 return nlk->portid != x->portid ||
421 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
422}
423
424static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
425 struct net *net, u32 portid)
426{
427 memset(arg, 0, sizeof(*arg));
428 write_pnet(&arg->pnet, net);
429 arg->portid = portid;
430}
431
432static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
433 struct net *net)
434{
435 struct netlink_compare_arg arg;
436
437 netlink_compare_arg_init(&arg, net, portid);
438 return rhashtable_lookup_fast(&table->hash, &arg,
439 netlink_rhashtable_params);
440}
441
442static int __netlink_insert(struct netlink_table *table, struct sock *sk)
443{
444 struct netlink_compare_arg arg;
445
446 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
447 return rhashtable_lookup_insert_key(&table->hash, &arg,
448 &nlk_sk(sk)->node,
449 netlink_rhashtable_params);
450}
451
452static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
453{
454 struct netlink_table *table = &nl_table[protocol];
455 struct sock *sk;
456
457 rcu_read_lock();
458 sk = __netlink_lookup(table, portid, net);
459 if (sk)
460 sock_hold(sk);
461 rcu_read_unlock();
462
463 return sk;
464}
465
466static const struct proto_ops netlink_ops;
467
468static void
469netlink_update_listeners(struct sock *sk)
470{
471 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
472 unsigned long mask;
473 unsigned int i;
474 struct listeners *listeners;
475
476 listeners = nl_deref_protected(tbl->listeners);
477 if (!listeners)
478 return;
479
480 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
481 mask = 0;
482 sk_for_each_bound(sk, &tbl->mc_list) {
483 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
484 mask |= nlk_sk(sk)->groups[i];
485 }
486 listeners->masks[i] = mask;
487 }
488 /* this function is only called with the netlink table "grabbed", which
489 * makes sure updates are visible before bind or setsockopt return. */
490}
491
492static int netlink_insert(struct sock *sk, u32 portid)
493{
494 struct netlink_table *table = &nl_table[sk->sk_protocol];
495 int err;
496
497 lock_sock(sk);
498
499 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
500 if (nlk_sk(sk)->bound)
501 goto err;
502
503 err = -ENOMEM;
504 if (BITS_PER_LONG > 32 &&
505 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
506 goto err;
507
508 nlk_sk(sk)->portid = portid;
509 sock_hold(sk);
510
511 err = __netlink_insert(table, sk);
512 if (err) {
513 /* In case the hashtable backend returns with -EBUSY
514 * from here, it must not escape to the caller.
515 */
516 if (unlikely(err == -EBUSY))
517 err = -EOVERFLOW;
518 if (err == -EEXIST)
519 err = -EADDRINUSE;
520 sock_put(sk);
521 goto err;
522 }
523
524 /* We need to ensure that the socket is hashed and visible. */
525 smp_wmb();
526 nlk_sk(sk)->bound = portid;
527
528err:
529 release_sock(sk);
530 return err;
531}
532
533static void netlink_remove(struct sock *sk)
534{
535 struct netlink_table *table;
536
537 table = &nl_table[sk->sk_protocol];
538 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
539 netlink_rhashtable_params)) {
540 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
541 __sock_put(sk);
542 }
543
544 netlink_table_grab();
545 if (nlk_sk(sk)->subscriptions) {
546 __sk_del_bind_node(sk);
547 netlink_update_listeners(sk);
548 }
549 if (sk->sk_protocol == NETLINK_GENERIC)
550 atomic_inc(&genl_sk_destructing_cnt);
551 netlink_table_ungrab();
552}
553
554static struct proto netlink_proto = {
555 .name = "NETLINK",
556 .owner = THIS_MODULE,
557 .obj_size = sizeof(struct netlink_sock),
558};
559
560static int __netlink_create(struct net *net, struct socket *sock,
561 struct mutex *cb_mutex, int protocol,
562 int kern)
563{
564 struct sock *sk;
565 struct netlink_sock *nlk;
566
567 sock->ops = &netlink_ops;
568
569 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
570 if (!sk)
571 return -ENOMEM;
572
573 sock_init_data(sock, sk);
574
575 nlk = nlk_sk(sk);
576 if (cb_mutex) {
577 nlk->cb_mutex = cb_mutex;
578 } else {
579 nlk->cb_mutex = &nlk->cb_def_mutex;
580 mutex_init(nlk->cb_mutex);
581 }
582 init_waitqueue_head(&nlk->wait);
583
584 sk->sk_destruct = netlink_sock_destruct;
585 sk->sk_protocol = protocol;
586 return 0;
587}
588
589static int netlink_create(struct net *net, struct socket *sock, int protocol,
590 int kern)
591{
592 struct module *module = NULL;
593 struct mutex *cb_mutex;
594 struct netlink_sock *nlk;
595 int (*bind)(struct net *net, int group);
596 void (*unbind)(struct net *net, int group);
597 int err = 0;
598
599 sock->state = SS_UNCONNECTED;
600
601 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
602 return -ESOCKTNOSUPPORT;
603
604 if (protocol < 0 || protocol >= MAX_LINKS)
605 return -EPROTONOSUPPORT;
606
607 netlink_lock_table();
608#ifdef CONFIG_MODULES
609 if (!nl_table[protocol].registered) {
610 netlink_unlock_table();
611 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
612 netlink_lock_table();
613 }
614#endif
615 if (nl_table[protocol].registered &&
616 try_module_get(nl_table[protocol].module))
617 module = nl_table[protocol].module;
618 else
619 err = -EPROTONOSUPPORT;
620 cb_mutex = nl_table[protocol].cb_mutex;
621 bind = nl_table[protocol].bind;
622 unbind = nl_table[protocol].unbind;
623 netlink_unlock_table();
624
625 if (err < 0)
626 goto out;
627
628 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
629 if (err < 0)
630 goto out_module;
631
632 local_bh_disable();
633 sock_prot_inuse_add(net, &netlink_proto, 1);
634 local_bh_enable();
635
636 nlk = nlk_sk(sock->sk);
637 nlk->module = module;
638 nlk->netlink_bind = bind;
639 nlk->netlink_unbind = unbind;
640out:
641 return err;
642
643out_module:
644 module_put(module);
645 goto out;
646}
647
648static void deferred_put_nlk_sk(struct rcu_head *head)
649{
650 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
651
652 sock_put(&nlk->sk);
653}
654
655static int netlink_release(struct socket *sock)
656{
657 struct sock *sk = sock->sk;
658 struct netlink_sock *nlk;
659
660 if (!sk)
661 return 0;
662
663 netlink_remove(sk);
664 sock_orphan(sk);
665 nlk = nlk_sk(sk);
666
667 /*
668 * OK. Socket is unlinked, any packets that arrive now
669 * will be purged.
670 */
671
672 /* must not acquire netlink_table_lock in any way again before unbind
673 * and notifying genetlink is done as otherwise it might deadlock
674 */
675 if (nlk->netlink_unbind) {
676 int i;
677
678 for (i = 0; i < nlk->ngroups; i++)
679 if (test_bit(i, nlk->groups))
680 nlk->netlink_unbind(sock_net(sk), i + 1);
681 }
682 if (sk->sk_protocol == NETLINK_GENERIC &&
683 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
684 wake_up(&genl_sk_destructing_waitq);
685
686 sock->sk = NULL;
687 wake_up_interruptible_all(&nlk->wait);
688
689 skb_queue_purge(&sk->sk_write_queue);
690
691 if (nlk->portid && nlk->bound) {
692 struct netlink_notify n = {
693 .net = sock_net(sk),
694 .protocol = sk->sk_protocol,
695 .portid = nlk->portid,
696 };
697 atomic_notifier_call_chain(&netlink_chain,
698 NETLINK_URELEASE, &n);
699 }
700
701 module_put(nlk->module);
702
703 if (netlink_is_kernel(sk)) {
704 netlink_table_grab();
705 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
706 if (--nl_table[sk->sk_protocol].registered == 0) {
707 struct listeners *old;
708
709 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
710 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
711 kfree_rcu(old, rcu);
712 nl_table[sk->sk_protocol].module = NULL;
713 nl_table[sk->sk_protocol].bind = NULL;
714 nl_table[sk->sk_protocol].unbind = NULL;
715 nl_table[sk->sk_protocol].flags = 0;
716 nl_table[sk->sk_protocol].registered = 0;
717 }
718 netlink_table_ungrab();
719 }
720
721 kfree(nlk->groups);
722 nlk->groups = NULL;
723
724 local_bh_disable();
725 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
726 local_bh_enable();
727 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
728 return 0;
729}
730
731static int netlink_autobind(struct socket *sock)
732{
733 struct sock *sk = sock->sk;
734 struct net *net = sock_net(sk);
735 struct netlink_table *table = &nl_table[sk->sk_protocol];
736 s32 portid = task_tgid_vnr(current);
737 int err;
738 s32 rover = -4096;
739 bool ok;
740
741retry:
742 cond_resched();
743 rcu_read_lock();
744 ok = !__netlink_lookup(table, portid, net);
745 rcu_read_unlock();
746 if (!ok) {
747 /* Bind collision, search negative portid values. */
748 if (rover == -4096)
749 /* rover will be in range [S32_MIN, -4097] */
750 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
751 else if (rover >= -4096)
752 rover = -4097;
753 portid = rover--;
754 goto retry;
755 }
756
757 err = netlink_insert(sk, portid);
758 if (err == -EADDRINUSE)
759 goto retry;
760
761 /* If 2 threads race to autobind, that is fine. */
762 if (err == -EBUSY)
763 err = 0;
764
765 return err;
766}
767
768/**
769 * __netlink_ns_capable - General netlink message capability test
770 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
771 * @user_ns: The user namespace of the capability to use
772 * @cap: The capability to use
773 *
774 * Test to see if the opener of the socket we received the message
775 * from had when the netlink socket was created and the sender of the
776 * message has has the capability @cap in the user namespace @user_ns.
777 */
778bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
779 struct user_namespace *user_ns, int cap)
780{
781 return ((nsp->flags & NETLINK_SKB_DST) ||
782 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
783 ns_capable(user_ns, cap);
784}
785EXPORT_SYMBOL(__netlink_ns_capable);
786
787/**
788 * netlink_ns_capable - General netlink message capability test
789 * @skb: socket buffer holding a netlink command from userspace
790 * @user_ns: The user namespace of the capability to use
791 * @cap: The capability to use
792 *
793 * Test to see if the opener of the socket we received the message
794 * from had when the netlink socket was created and the sender of the
795 * message has has the capability @cap in the user namespace @user_ns.
796 */
797bool netlink_ns_capable(const struct sk_buff *skb,
798 struct user_namespace *user_ns, int cap)
799{
800 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
801}
802EXPORT_SYMBOL(netlink_ns_capable);
803
804/**
805 * netlink_capable - Netlink global message capability test
806 * @skb: socket buffer holding a netlink command from userspace
807 * @cap: The capability to use
808 *
809 * Test to see if the opener of the socket we received the message
810 * from had when the netlink socket was created and the sender of the
811 * message has has the capability @cap in all user namespaces.
812 */
813bool netlink_capable(const struct sk_buff *skb, int cap)
814{
815 return netlink_ns_capable(skb, &init_user_ns, cap);
816}
817EXPORT_SYMBOL(netlink_capable);
818
819/**
820 * netlink_net_capable - Netlink network namespace message capability test
821 * @skb: socket buffer holding a netlink command from userspace
822 * @cap: The capability to use
823 *
824 * Test to see if the opener of the socket we received the message
825 * from had when the netlink socket was created and the sender of the
826 * message has has the capability @cap over the network namespace of
827 * the socket we received the message from.
828 */
829bool netlink_net_capable(const struct sk_buff *skb, int cap)
830{
831 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
832}
833EXPORT_SYMBOL(netlink_net_capable);
834
835static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
836{
837 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
838 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
839}
840
841static void
842netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
843{
844 struct netlink_sock *nlk = nlk_sk(sk);
845
846 if (nlk->subscriptions && !subscriptions)
847 __sk_del_bind_node(sk);
848 else if (!nlk->subscriptions && subscriptions)
849 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
850 nlk->subscriptions = subscriptions;
851}
852
853static int netlink_realloc_groups(struct sock *sk)
854{
855 struct netlink_sock *nlk = nlk_sk(sk);
856 unsigned int groups;
857 unsigned long *new_groups;
858 int err = 0;
859
860 netlink_table_grab();
861
862 groups = nl_table[sk->sk_protocol].groups;
863 if (!nl_table[sk->sk_protocol].registered) {
864 err = -ENOENT;
865 goto out_unlock;
866 }
867
868 if (nlk->ngroups >= groups)
869 goto out_unlock;
870
871 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
872 if (new_groups == NULL) {
873 err = -ENOMEM;
874 goto out_unlock;
875 }
876 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
877 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
878
879 nlk->groups = new_groups;
880 nlk->ngroups = groups;
881 out_unlock:
882 netlink_table_ungrab();
883 return err;
884}
885
886static void netlink_undo_bind(int group, long unsigned int groups,
887 struct sock *sk)
888{
889 struct netlink_sock *nlk = nlk_sk(sk);
890 int undo;
891
892 if (!nlk->netlink_unbind)
893 return;
894
895 for (undo = 0; undo < group; undo++)
896 if (test_bit(undo, &groups))
897 nlk->netlink_unbind(sock_net(sk), undo + 1);
898}
899
900static int netlink_bind(struct socket *sock, struct sockaddr *addr,
901 int addr_len)
902{
903 struct sock *sk = sock->sk;
904 struct net *net = sock_net(sk);
905 struct netlink_sock *nlk = nlk_sk(sk);
906 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
907 int err;
908 long unsigned int groups = nladdr->nl_groups;
909 bool bound;
910
911 if (addr_len < sizeof(struct sockaddr_nl))
912 return -EINVAL;
913
914 if (nladdr->nl_family != AF_NETLINK)
915 return -EINVAL;
916
917 /* Only superuser is allowed to listen multicasts */
918 if (groups) {
919 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
920 return -EPERM;
921 err = netlink_realloc_groups(sk);
922 if (err)
923 return err;
924 }
925
926 bound = nlk->bound;
927 if (bound) {
928 /* Ensure nlk->portid is up-to-date. */
929 smp_rmb();
930
931 if (nladdr->nl_pid != nlk->portid)
932 return -EINVAL;
933 }
934
935 if (nlk->netlink_bind && groups) {
936 int group;
937
938 for (group = 0; group < nlk->ngroups; group++) {
939 if (!test_bit(group, &groups))
940 continue;
941 err = nlk->netlink_bind(net, group + 1);
942 if (!err)
943 continue;
944 netlink_undo_bind(group, groups, sk);
945 return err;
946 }
947 }
948
949 /* No need for barriers here as we return to user-space without
950 * using any of the bound attributes.
951 */
952 if (!bound) {
953 err = nladdr->nl_pid ?
954 netlink_insert(sk, nladdr->nl_pid) :
955 netlink_autobind(sock);
956 if (err) {
957 netlink_undo_bind(nlk->ngroups, groups, sk);
958 return err;
959 }
960 }
961
962 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
963 return 0;
964
965 netlink_table_grab();
966 netlink_update_subscriptions(sk, nlk->subscriptions +
967 hweight32(groups) -
968 hweight32(nlk->groups[0]));
969 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
970 netlink_update_listeners(sk);
971 netlink_table_ungrab();
972
973 return 0;
974}
975
976static int netlink_connect(struct socket *sock, struct sockaddr *addr,
977 int alen, int flags)
978{
979 int err = 0;
980 struct sock *sk = sock->sk;
981 struct netlink_sock *nlk = nlk_sk(sk);
982 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
983
984 if (alen < sizeof(addr->sa_family))
985 return -EINVAL;
986
987 if (addr->sa_family == AF_UNSPEC) {
988 sk->sk_state = NETLINK_UNCONNECTED;
989 nlk->dst_portid = 0;
990 nlk->dst_group = 0;
991 return 0;
992 }
993 if (addr->sa_family != AF_NETLINK)
994 return -EINVAL;
995
996 if ((nladdr->nl_groups || nladdr->nl_pid) &&
997 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
998 return -EPERM;
999
1000 /* No need for barriers here as we return to user-space without
1001 * using any of the bound attributes.
1002 */
1003 if (!nlk->bound)
1004 err = netlink_autobind(sock);
1005
1006 if (err == 0) {
1007 sk->sk_state = NETLINK_CONNECTED;
1008 nlk->dst_portid = nladdr->nl_pid;
1009 nlk->dst_group = ffs(nladdr->nl_groups);
1010 }
1011
1012 return err;
1013}
1014
1015static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1016 int *addr_len, int peer)
1017{
1018 struct sock *sk = sock->sk;
1019 struct netlink_sock *nlk = nlk_sk(sk);
1020 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1021
1022 nladdr->nl_family = AF_NETLINK;
1023 nladdr->nl_pad = 0;
1024 *addr_len = sizeof(*nladdr);
1025
1026 if (peer) {
1027 nladdr->nl_pid = nlk->dst_portid;
1028 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1029 } else {
1030 nladdr->nl_pid = nlk->portid;
1031 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1032 }
1033 return 0;
1034}
1035
1036static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1037 unsigned long arg)
1038{
1039 /* try to hand this ioctl down to the NIC drivers.
1040 */
1041 return -ENOIOCTLCMD;
1042}
1043
1044static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1045{
1046 struct sock *sock;
1047 struct netlink_sock *nlk;
1048
1049 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1050 if (!sock)
1051 return ERR_PTR(-ECONNREFUSED);
1052
1053 /* Don't bother queuing skb if kernel socket has no input function */
1054 nlk = nlk_sk(sock);
1055 if (sock->sk_state == NETLINK_CONNECTED &&
1056 nlk->dst_portid != nlk_sk(ssk)->portid) {
1057 sock_put(sock);
1058 return ERR_PTR(-ECONNREFUSED);
1059 }
1060 return sock;
1061}
1062
1063struct sock *netlink_getsockbyfilp(struct file *filp)
1064{
1065 struct inode *inode = file_inode(filp);
1066 struct sock *sock;
1067
1068 if (!S_ISSOCK(inode->i_mode))
1069 return ERR_PTR(-ENOTSOCK);
1070
1071 sock = SOCKET_I(inode)->sk;
1072 if (sock->sk_family != AF_NETLINK)
1073 return ERR_PTR(-EINVAL);
1074
1075 sock_hold(sock);
1076 return sock;
1077}
1078
1079static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1080 int broadcast)
1081{
1082 struct sk_buff *skb;
1083 void *data;
1084
1085 if (size <= NLMSG_GOODSIZE || broadcast)
1086 return alloc_skb(size, GFP_KERNEL);
1087
1088 size = SKB_DATA_ALIGN(size) +
1089 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1090
1091 data = vmalloc(size);
1092 if (data == NULL)
1093 return NULL;
1094
1095 skb = __build_skb(data, size);
1096 if (skb == NULL)
1097 vfree(data);
1098 else
1099 skb->destructor = netlink_skb_destructor;
1100
1101 return skb;
1102}
1103
1104/*
1105 * Attach a skb to a netlink socket.
1106 * The caller must hold a reference to the destination socket. On error, the
1107 * reference is dropped. The skb is not send to the destination, just all
1108 * all error checks are performed and memory in the queue is reserved.
1109 * Return values:
1110 * < 0: error. skb freed, reference to sock dropped.
1111 * 0: continue
1112 * 1: repeat lookup - reference dropped while waiting for socket memory.
1113 */
1114int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1115 long *timeo, struct sock *ssk)
1116{
1117 struct netlink_sock *nlk;
1118
1119 nlk = nlk_sk(sk);
1120
1121 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1122 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1123 DECLARE_WAITQUEUE(wait, current);
1124 if (!*timeo) {
1125 if (!ssk || netlink_is_kernel(ssk))
1126 netlink_overrun(sk);
1127 sock_put(sk);
1128 kfree_skb(skb);
1129 return -EAGAIN;
1130 }
1131
1132 __set_current_state(TASK_INTERRUPTIBLE);
1133 add_wait_queue(&nlk->wait, &wait);
1134
1135 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1136 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1137 !sock_flag(sk, SOCK_DEAD))
1138 *timeo = schedule_timeout(*timeo);
1139
1140 __set_current_state(TASK_RUNNING);
1141 remove_wait_queue(&nlk->wait, &wait);
1142 sock_put(sk);
1143
1144 if (signal_pending(current)) {
1145 kfree_skb(skb);
1146 return sock_intr_errno(*timeo);
1147 }
1148 return 1;
1149 }
1150 netlink_skb_set_owner_r(skb, sk);
1151 return 0;
1152}
1153
1154static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1155{
1156 int len = skb->len;
1157
1158 netlink_deliver_tap(skb);
1159
1160 skb_queue_tail(&sk->sk_receive_queue, skb);
1161 sk->sk_data_ready(sk);
1162 return len;
1163}
1164
1165int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1166{
1167 int len = __netlink_sendskb(sk, skb);
1168
1169 sock_put(sk);
1170 return len;
1171}
1172
1173void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1174{
1175 kfree_skb(skb);
1176 sock_put(sk);
1177}
1178
1179static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1180{
1181 int delta;
1182
1183 WARN_ON(skb->sk != NULL);
1184 delta = skb->end - skb->tail;
1185 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1186 return skb;
1187
1188 if (skb_shared(skb)) {
1189 struct sk_buff *nskb = skb_clone(skb, allocation);
1190 if (!nskb)
1191 return skb;
1192 consume_skb(skb);
1193 skb = nskb;
1194 }
1195
1196 if (!pskb_expand_head(skb, 0, -delta, allocation))
1197 skb->truesize -= delta;
1198
1199 return skb;
1200}
1201
1202static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1203 struct sock *ssk)
1204{
1205 int ret;
1206 struct netlink_sock *nlk = nlk_sk(sk);
1207
1208 ret = -ECONNREFUSED;
1209 if (nlk->netlink_rcv != NULL) {
1210 ret = skb->len;
1211 netlink_skb_set_owner_r(skb, sk);
1212 NETLINK_CB(skb).sk = ssk;
1213 netlink_deliver_tap_kernel(sk, ssk, skb);
1214 nlk->netlink_rcv(skb);
1215 consume_skb(skb);
1216 } else {
1217 kfree_skb(skb);
1218 }
1219 sock_put(sk);
1220 return ret;
1221}
1222
1223int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1224 u32 portid, int nonblock)
1225{
1226 struct sock *sk;
1227 int err;
1228 long timeo;
1229
1230 skb = netlink_trim(skb, gfp_any());
1231
1232 timeo = sock_sndtimeo(ssk, nonblock);
1233retry:
1234 sk = netlink_getsockbyportid(ssk, portid);
1235 if (IS_ERR(sk)) {
1236 kfree_skb(skb);
1237 return PTR_ERR(sk);
1238 }
1239 if (netlink_is_kernel(sk))
1240 return netlink_unicast_kernel(sk, skb, ssk);
1241
1242 if (sk_filter(sk, skb)) {
1243 err = skb->len;
1244 kfree_skb(skb);
1245 sock_put(sk);
1246 return err;
1247 }
1248
1249 err = netlink_attachskb(sk, skb, &timeo, ssk);
1250 if (err == 1)
1251 goto retry;
1252 if (err)
1253 return err;
1254
1255 return netlink_sendskb(sk, skb);
1256}
1257EXPORT_SYMBOL(netlink_unicast);
1258
1259int netlink_has_listeners(struct sock *sk, unsigned int group)
1260{
1261 int res = 0;
1262 struct listeners *listeners;
1263
1264 BUG_ON(!netlink_is_kernel(sk));
1265
1266 rcu_read_lock();
1267 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1268
1269 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1270 res = test_bit(group - 1, listeners->masks);
1271
1272 rcu_read_unlock();
1273
1274 return res;
1275}
1276EXPORT_SYMBOL_GPL(netlink_has_listeners);
1277
1278static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1279{
1280 struct netlink_sock *nlk = nlk_sk(sk);
1281
1282 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1283 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1284 netlink_skb_set_owner_r(skb, sk);
1285 __netlink_sendskb(sk, skb);
1286 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1287 }
1288 return -1;
1289}
1290
1291struct netlink_broadcast_data {
1292 struct sock *exclude_sk;
1293 struct net *net;
1294 u32 portid;
1295 u32 group;
1296 int failure;
1297 int delivery_failure;
1298 int congested;
1299 int delivered;
1300 gfp_t allocation;
1301 struct sk_buff *skb, *skb2;
1302 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1303 void *tx_data;
1304};
1305
1306static void do_one_broadcast(struct sock *sk,
1307 struct netlink_broadcast_data *p)
1308{
1309 struct netlink_sock *nlk = nlk_sk(sk);
1310 int val;
1311
1312 if (p->exclude_sk == sk)
1313 return;
1314
1315 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1316 !test_bit(p->group - 1, nlk->groups))
1317 return;
1318
1319 if (!net_eq(sock_net(sk), p->net)) {
1320 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1321 return;
1322
1323 if (!peernet_has_id(sock_net(sk), p->net))
1324 return;
1325
1326 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1327 CAP_NET_BROADCAST))
1328 return;
1329 }
1330
1331 if (p->failure) {
1332 netlink_overrun(sk);
1333 return;
1334 }
1335
1336 sock_hold(sk);
1337 if (p->skb2 == NULL) {
1338 if (skb_shared(p->skb)) {
1339 p->skb2 = skb_clone(p->skb, p->allocation);
1340 } else {
1341 p->skb2 = skb_get(p->skb);
1342 /*
1343 * skb ownership may have been set when
1344 * delivered to a previous socket.
1345 */
1346 skb_orphan(p->skb2);
1347 }
1348 }
1349 if (p->skb2 == NULL) {
1350 netlink_overrun(sk);
1351 /* Clone failed. Notify ALL listeners. */
1352 p->failure = 1;
1353 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1354 p->delivery_failure = 1;
1355 goto out;
1356 }
1357 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1358 kfree_skb(p->skb2);
1359 p->skb2 = NULL;
1360 goto out;
1361 }
1362 if (sk_filter(sk, p->skb2)) {
1363 kfree_skb(p->skb2);
1364 p->skb2 = NULL;
1365 goto out;
1366 }
1367 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1368 NETLINK_CB(p->skb2).nsid_is_set = true;
1369 val = netlink_broadcast_deliver(sk, p->skb2);
1370 if (val < 0) {
1371 netlink_overrun(sk);
1372 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1373 p->delivery_failure = 1;
1374 } else {
1375 p->congested |= val;
1376 p->delivered = 1;
1377 p->skb2 = NULL;
1378 }
1379out:
1380 sock_put(sk);
1381}
1382
1383int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1384 u32 group, gfp_t allocation,
1385 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1386 void *filter_data)
1387{
1388 struct net *net = sock_net(ssk);
1389 struct netlink_broadcast_data info;
1390 struct sock *sk;
1391
1392 skb = netlink_trim(skb, allocation);
1393
1394 info.exclude_sk = ssk;
1395 info.net = net;
1396 info.portid = portid;
1397 info.group = group;
1398 info.failure = 0;
1399 info.delivery_failure = 0;
1400 info.congested = 0;
1401 info.delivered = 0;
1402 info.allocation = allocation;
1403 info.skb = skb;
1404 info.skb2 = NULL;
1405 info.tx_filter = filter;
1406 info.tx_data = filter_data;
1407
1408 /* While we sleep in clone, do not allow to change socket list */
1409
1410 netlink_lock_table();
1411
1412 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1413 do_one_broadcast(sk, &info);
1414
1415 consume_skb(skb);
1416
1417 netlink_unlock_table();
1418
1419 if (info.delivery_failure) {
1420 kfree_skb(info.skb2);
1421 return -ENOBUFS;
1422 }
1423 consume_skb(info.skb2);
1424
1425 if (info.delivered) {
1426 if (info.congested && gfpflags_allow_blocking(allocation))
1427 yield();
1428 return 0;
1429 }
1430 return -ESRCH;
1431}
1432EXPORT_SYMBOL(netlink_broadcast_filtered);
1433
1434int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1435 u32 group, gfp_t allocation)
1436{
1437 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1438 NULL, NULL);
1439}
1440EXPORT_SYMBOL(netlink_broadcast);
1441
1442struct netlink_set_err_data {
1443 struct sock *exclude_sk;
1444 u32 portid;
1445 u32 group;
1446 int code;
1447};
1448
1449static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1450{
1451 struct netlink_sock *nlk = nlk_sk(sk);
1452 int ret = 0;
1453
1454 if (sk == p->exclude_sk)
1455 goto out;
1456
1457 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1458 goto out;
1459
1460 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1461 !test_bit(p->group - 1, nlk->groups))
1462 goto out;
1463
1464 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1465 ret = 1;
1466 goto out;
1467 }
1468
1469 sk->sk_err = p->code;
1470 sk->sk_error_report(sk);
1471out:
1472 return ret;
1473}
1474
1475/**
1476 * netlink_set_err - report error to broadcast listeners
1477 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1478 * @portid: the PORTID of a process that we want to skip (if any)
1479 * @group: the broadcast group that will notice the error
1480 * @code: error code, must be negative (as usual in kernelspace)
1481 *
1482 * This function returns the number of broadcast listeners that have set the
1483 * NETLINK_NO_ENOBUFS socket option.
1484 */
1485int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1486{
1487 struct netlink_set_err_data info;
1488 struct sock *sk;
1489 int ret = 0;
1490
1491 info.exclude_sk = ssk;
1492 info.portid = portid;
1493 info.group = group;
1494 /* sk->sk_err wants a positive error value */
1495 info.code = -code;
1496
1497 read_lock(&nl_table_lock);
1498
1499 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1500 ret += do_one_set_err(sk, &info);
1501
1502 read_unlock(&nl_table_lock);
1503 return ret;
1504}
1505EXPORT_SYMBOL(netlink_set_err);
1506
1507/* must be called with netlink table grabbed */
1508static void netlink_update_socket_mc(struct netlink_sock *nlk,
1509 unsigned int group,
1510 int is_new)
1511{
1512 int old, new = !!is_new, subscriptions;
1513
1514 old = test_bit(group - 1, nlk->groups);
1515 subscriptions = nlk->subscriptions - old + new;
1516 if (new)
1517 __set_bit(group - 1, nlk->groups);
1518 else
1519 __clear_bit(group - 1, nlk->groups);
1520 netlink_update_subscriptions(&nlk->sk, subscriptions);
1521 netlink_update_listeners(&nlk->sk);
1522}
1523
1524static int netlink_setsockopt(struct socket *sock, int level, int optname,
1525 char __user *optval, unsigned int optlen)
1526{
1527 struct sock *sk = sock->sk;
1528 struct netlink_sock *nlk = nlk_sk(sk);
1529 unsigned int val = 0;
1530 int err;
1531
1532 if (level != SOL_NETLINK)
1533 return -ENOPROTOOPT;
1534
1535 if (optlen >= sizeof(int) &&
1536 get_user(val, (unsigned int __user *)optval))
1537 return -EFAULT;
1538
1539 switch (optname) {
1540 case NETLINK_PKTINFO:
1541 if (val)
1542 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1543 else
1544 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1545 err = 0;
1546 break;
1547 case NETLINK_ADD_MEMBERSHIP:
1548 case NETLINK_DROP_MEMBERSHIP: {
1549 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1550 return -EPERM;
1551 err = netlink_realloc_groups(sk);
1552 if (err)
1553 return err;
1554 if (!val || val - 1 >= nlk->ngroups)
1555 return -EINVAL;
1556 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1557 err = nlk->netlink_bind(sock_net(sk), val);
1558 if (err)
1559 return err;
1560 }
1561 netlink_table_grab();
1562 netlink_update_socket_mc(nlk, val,
1563 optname == NETLINK_ADD_MEMBERSHIP);
1564 netlink_table_ungrab();
1565 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1566 nlk->netlink_unbind(sock_net(sk), val);
1567
1568 err = 0;
1569 break;
1570 }
1571 case NETLINK_BROADCAST_ERROR:
1572 if (val)
1573 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1574 else
1575 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1576 err = 0;
1577 break;
1578 case NETLINK_NO_ENOBUFS:
1579 if (val) {
1580 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1581 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1582 wake_up_interruptible(&nlk->wait);
1583 } else {
1584 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1585 }
1586 err = 0;
1587 break;
1588 case NETLINK_LISTEN_ALL_NSID:
1589 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1590 return -EPERM;
1591
1592 if (val)
1593 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1594 else
1595 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1596 err = 0;
1597 break;
1598 case NETLINK_CAP_ACK:
1599 if (val)
1600 nlk->flags |= NETLINK_F_CAP_ACK;
1601 else
1602 nlk->flags &= ~NETLINK_F_CAP_ACK;
1603 err = 0;
1604 break;
1605 default:
1606 err = -ENOPROTOOPT;
1607 }
1608 return err;
1609}
1610
1611static int netlink_getsockopt(struct socket *sock, int level, int optname,
1612 char __user *optval, int __user *optlen)
1613{
1614 struct sock *sk = sock->sk;
1615 struct netlink_sock *nlk = nlk_sk(sk);
1616 int len, val, err;
1617
1618 if (level != SOL_NETLINK)
1619 return -ENOPROTOOPT;
1620
1621 if (get_user(len, optlen))
1622 return -EFAULT;
1623 if (len < 0)
1624 return -EINVAL;
1625
1626 switch (optname) {
1627 case NETLINK_PKTINFO:
1628 if (len < sizeof(int))
1629 return -EINVAL;
1630 len = sizeof(int);
1631 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1632 if (put_user(len, optlen) ||
1633 put_user(val, optval))
1634 return -EFAULT;
1635 err = 0;
1636 break;
1637 case NETLINK_BROADCAST_ERROR:
1638 if (len < sizeof(int))
1639 return -EINVAL;
1640 len = sizeof(int);
1641 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1642 if (put_user(len, optlen) ||
1643 put_user(val, optval))
1644 return -EFAULT;
1645 err = 0;
1646 break;
1647 case NETLINK_NO_ENOBUFS:
1648 if (len < sizeof(int))
1649 return -EINVAL;
1650 len = sizeof(int);
1651 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1652 if (put_user(len, optlen) ||
1653 put_user(val, optval))
1654 return -EFAULT;
1655 err = 0;
1656 break;
1657 case NETLINK_LIST_MEMBERSHIPS: {
1658 int pos, idx, shift;
1659
1660 err = 0;
1661 netlink_lock_table();
1662 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1663 if (len - pos < sizeof(u32))
1664 break;
1665
1666 idx = pos / sizeof(unsigned long);
1667 shift = (pos % sizeof(unsigned long)) * 8;
1668 if (put_user((u32)(nlk->groups[idx] >> shift),
1669 (u32 __user *)(optval + pos))) {
1670 err = -EFAULT;
1671 break;
1672 }
1673 }
1674 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1675 err = -EFAULT;
1676 netlink_unlock_table();
1677 break;
1678 }
1679 case NETLINK_CAP_ACK:
1680 if (len < sizeof(int))
1681 return -EINVAL;
1682 len = sizeof(int);
1683 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1684 if (put_user(len, optlen) ||
1685 put_user(val, optval))
1686 return -EFAULT;
1687 err = 0;
1688 break;
1689 default:
1690 err = -ENOPROTOOPT;
1691 }
1692 return err;
1693}
1694
1695static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1696{
1697 struct nl_pktinfo info;
1698
1699 info.group = NETLINK_CB(skb).dst_group;
1700 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1701}
1702
1703static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1704 struct sk_buff *skb)
1705{
1706 if (!NETLINK_CB(skb).nsid_is_set)
1707 return;
1708
1709 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1710 &NETLINK_CB(skb).nsid);
1711}
1712
1713static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1714{
1715 struct sock *sk = sock->sk;
1716 struct netlink_sock *nlk = nlk_sk(sk);
1717 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1718 u32 dst_portid;
1719 u32 dst_group;
1720 struct sk_buff *skb;
1721 int err;
1722 struct scm_cookie scm;
1723 u32 netlink_skb_flags = 0;
1724
1725 if (msg->msg_flags&MSG_OOB)
1726 return -EOPNOTSUPP;
1727
1728 err = scm_send(sock, msg, &scm, true);
1729 if (err < 0)
1730 return err;
1731
1732 if (msg->msg_namelen) {
1733 err = -EINVAL;
1734 if (addr->nl_family != AF_NETLINK)
1735 goto out;
1736 dst_portid = addr->nl_pid;
1737 dst_group = ffs(addr->nl_groups);
1738 err = -EPERM;
1739 if ((dst_group || dst_portid) &&
1740 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1741 goto out;
1742 netlink_skb_flags |= NETLINK_SKB_DST;
1743 } else {
1744 dst_portid = nlk->dst_portid;
1745 dst_group = nlk->dst_group;
1746 }
1747
1748 if (!nlk->bound) {
1749 err = netlink_autobind(sock);
1750 if (err)
1751 goto out;
1752 } else {
1753 /* Ensure nlk is hashed and visible. */
1754 smp_rmb();
1755 }
1756
1757 err = -EMSGSIZE;
1758 if (len > sk->sk_sndbuf - 32)
1759 goto out;
1760 err = -ENOBUFS;
1761 skb = netlink_alloc_large_skb(len, dst_group);
1762 if (skb == NULL)
1763 goto out;
1764
1765 NETLINK_CB(skb).portid = nlk->portid;
1766 NETLINK_CB(skb).dst_group = dst_group;
1767 NETLINK_CB(skb).creds = scm.creds;
1768 NETLINK_CB(skb).flags = netlink_skb_flags;
1769
1770 err = -EFAULT;
1771 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1772 kfree_skb(skb);
1773 goto out;
1774 }
1775
1776 err = security_netlink_send(sk, skb);
1777 if (err) {
1778 kfree_skb(skb);
1779 goto out;
1780 }
1781
1782 if (dst_group) {
1783 atomic_inc(&skb->users);
1784 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1785 }
1786 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1787
1788out:
1789 scm_destroy(&scm);
1790 return err;
1791}
1792
1793static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1794 int flags)
1795{
1796 struct scm_cookie scm;
1797 struct sock *sk = sock->sk;
1798 struct netlink_sock *nlk = nlk_sk(sk);
1799 int noblock = flags&MSG_DONTWAIT;
1800 size_t copied;
1801 struct sk_buff *skb, *data_skb;
1802 int err, ret;
1803
1804 if (flags&MSG_OOB)
1805 return -EOPNOTSUPP;
1806
1807 copied = 0;
1808
1809 skb = skb_recv_datagram(sk, flags, noblock, &err);
1810 if (skb == NULL)
1811 goto out;
1812
1813 data_skb = skb;
1814
1815#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1816 if (unlikely(skb_shinfo(skb)->frag_list)) {
1817 /*
1818 * If this skb has a frag_list, then here that means that we
1819 * will have to use the frag_list skb's data for compat tasks
1820 * and the regular skb's data for normal (non-compat) tasks.
1821 *
1822 * If we need to send the compat skb, assign it to the
1823 * 'data_skb' variable so that it will be used below for data
1824 * copying. We keep 'skb' for everything else, including
1825 * freeing both later.
1826 */
1827 if (flags & MSG_CMSG_COMPAT)
1828 data_skb = skb_shinfo(skb)->frag_list;
1829 }
1830#endif
1831
1832 /* Record the max length of recvmsg() calls for future allocations */
1833 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1834 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1835 16384);
1836
1837 copied = data_skb->len;
1838 if (len < copied) {
1839 msg->msg_flags |= MSG_TRUNC;
1840 copied = len;
1841 }
1842
1843 skb_reset_transport_header(data_skb);
1844 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1845
1846 if (msg->msg_name) {
1847 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1848 addr->nl_family = AF_NETLINK;
1849 addr->nl_pad = 0;
1850 addr->nl_pid = NETLINK_CB(skb).portid;
1851 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1852 msg->msg_namelen = sizeof(*addr);
1853 }
1854
1855 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1856 netlink_cmsg_recv_pktinfo(msg, skb);
1857 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1858 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1859
1860 memset(&scm, 0, sizeof(scm));
1861 scm.creds = *NETLINK_CREDS(skb);
1862 if (flags & MSG_TRUNC)
1863 copied = data_skb->len;
1864
1865 skb_free_datagram(sk, skb);
1866
1867 if (nlk->cb_running &&
1868 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1869 ret = netlink_dump(sk);
1870 if (ret) {
1871 sk->sk_err = -ret;
1872 sk->sk_error_report(sk);
1873 }
1874 }
1875
1876 scm_recv(sock, msg, &scm, flags);
1877out:
1878 netlink_rcv_wake(sk);
1879 return err ? : copied;
1880}
1881
1882static void netlink_data_ready(struct sock *sk)
1883{
1884 BUG();
1885}
1886
1887/*
1888 * We export these functions to other modules. They provide a
1889 * complete set of kernel non-blocking support for message
1890 * queueing.
1891 */
1892
1893struct sock *
1894__netlink_kernel_create(struct net *net, int unit, struct module *module,
1895 struct netlink_kernel_cfg *cfg)
1896{
1897 struct socket *sock;
1898 struct sock *sk;
1899 struct netlink_sock *nlk;
1900 struct listeners *listeners = NULL;
1901 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
1902 unsigned int groups;
1903
1904 BUG_ON(!nl_table);
1905
1906 if (unit < 0 || unit >= MAX_LINKS)
1907 return NULL;
1908
1909 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1910 return NULL;
1911
1912 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
1913 goto out_sock_release_nosk;
1914
1915 sk = sock->sk;
1916
1917 if (!cfg || cfg->groups < 32)
1918 groups = 32;
1919 else
1920 groups = cfg->groups;
1921
1922 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1923 if (!listeners)
1924 goto out_sock_release;
1925
1926 sk->sk_data_ready = netlink_data_ready;
1927 if (cfg && cfg->input)
1928 nlk_sk(sk)->netlink_rcv = cfg->input;
1929
1930 if (netlink_insert(sk, 0))
1931 goto out_sock_release;
1932
1933 nlk = nlk_sk(sk);
1934 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
1935
1936 netlink_table_grab();
1937 if (!nl_table[unit].registered) {
1938 nl_table[unit].groups = groups;
1939 rcu_assign_pointer(nl_table[unit].listeners, listeners);
1940 nl_table[unit].cb_mutex = cb_mutex;
1941 nl_table[unit].module = module;
1942 if (cfg) {
1943 nl_table[unit].bind = cfg->bind;
1944 nl_table[unit].unbind = cfg->unbind;
1945 nl_table[unit].flags = cfg->flags;
1946 if (cfg->compare)
1947 nl_table[unit].compare = cfg->compare;
1948 }
1949 nl_table[unit].registered = 1;
1950 } else {
1951 kfree(listeners);
1952 nl_table[unit].registered++;
1953 }
1954 netlink_table_ungrab();
1955 return sk;
1956
1957out_sock_release:
1958 kfree(listeners);
1959 netlink_kernel_release(sk);
1960 return NULL;
1961
1962out_sock_release_nosk:
1963 sock_release(sock);
1964 return NULL;
1965}
1966EXPORT_SYMBOL(__netlink_kernel_create);
1967
1968void
1969netlink_kernel_release(struct sock *sk)
1970{
1971 if (sk == NULL || sk->sk_socket == NULL)
1972 return;
1973
1974 sock_release(sk->sk_socket);
1975}
1976EXPORT_SYMBOL(netlink_kernel_release);
1977
1978int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1979{
1980 struct listeners *new, *old;
1981 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1982
1983 if (groups < 32)
1984 groups = 32;
1985
1986 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1987 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
1988 if (!new)
1989 return -ENOMEM;
1990 old = nl_deref_protected(tbl->listeners);
1991 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
1992 rcu_assign_pointer(tbl->listeners, new);
1993
1994 kfree_rcu(old, rcu);
1995 }
1996 tbl->groups = groups;
1997
1998 return 0;
1999}
2000
2001/**
2002 * netlink_change_ngroups - change number of multicast groups
2003 *
2004 * This changes the number of multicast groups that are available
2005 * on a certain netlink family. Note that it is not possible to
2006 * change the number of groups to below 32. Also note that it does
2007 * not implicitly call netlink_clear_multicast_users() when the
2008 * number of groups is reduced.
2009 *
2010 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2011 * @groups: The new number of groups.
2012 */
2013int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2014{
2015 int err;
2016
2017 netlink_table_grab();
2018 err = __netlink_change_ngroups(sk, groups);
2019 netlink_table_ungrab();
2020
2021 return err;
2022}
2023
2024void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2025{
2026 struct sock *sk;
2027 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2028
2029 sk_for_each_bound(sk, &tbl->mc_list)
2030 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2031}
2032
2033struct nlmsghdr *
2034__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2035{
2036 struct nlmsghdr *nlh;
2037 int size = nlmsg_msg_size(len);
2038
2039 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2040 nlh->nlmsg_type = type;
2041 nlh->nlmsg_len = size;
2042 nlh->nlmsg_flags = flags;
2043 nlh->nlmsg_pid = portid;
2044 nlh->nlmsg_seq = seq;
2045 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2046 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2047 return nlh;
2048}
2049EXPORT_SYMBOL(__nlmsg_put);
2050
2051/*
2052 * It looks a bit ugly.
2053 * It would be better to create kernel thread.
2054 */
2055
2056static int netlink_dump(struct sock *sk)
2057{
2058 struct netlink_sock *nlk = nlk_sk(sk);
2059 struct netlink_callback *cb;
2060 struct sk_buff *skb = NULL;
2061 struct nlmsghdr *nlh;
2062 int len, err = -ENOBUFS;
2063 int alloc_min_size;
2064 int alloc_size;
2065
2066 mutex_lock(nlk->cb_mutex);
2067 if (!nlk->cb_running) {
2068 err = -EINVAL;
2069 goto errout_skb;
2070 }
2071
2072 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2073 goto errout_skb;
2074
2075 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2076 * required, but it makes sense to _attempt_ a 16K bytes allocation
2077 * to reduce number of system calls on dump operations, if user
2078 * ever provided a big enough buffer.
2079 */
2080 cb = &nlk->cb;
2081 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2082
2083 if (alloc_min_size < nlk->max_recvmsg_len) {
2084 alloc_size = nlk->max_recvmsg_len;
2085 skb = alloc_skb(alloc_size, GFP_KERNEL |
2086 __GFP_NOWARN | __GFP_NORETRY);
2087 }
2088 if (!skb) {
2089 alloc_size = alloc_min_size;
2090 skb = alloc_skb(alloc_size, GFP_KERNEL);
2091 }
2092 if (!skb)
2093 goto errout_skb;
2094
2095 /* Trim skb to allocated size. User is expected to provide buffer as
2096 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2097 * netlink_recvmsg())). dump will pack as many smaller messages as
2098 * could fit within the allocated skb. skb is typically allocated
2099 * with larger space than required (could be as much as near 2x the
2100 * requested size with align to next power of 2 approach). Allowing
2101 * dump to use the excess space makes it difficult for a user to have a
2102 * reasonable static buffer based on the expected largest dump of a
2103 * single netdev. The outcome is MSG_TRUNC error.
2104 */
2105 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2106 netlink_skb_set_owner_r(skb, sk);
2107
2108 len = cb->dump(skb, cb);
2109
2110 if (len > 0) {
2111 mutex_unlock(nlk->cb_mutex);
2112
2113 if (sk_filter(sk, skb))
2114 kfree_skb(skb);
2115 else
2116 __netlink_sendskb(sk, skb);
2117 return 0;
2118 }
2119
2120 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2121 if (!nlh)
2122 goto errout_skb;
2123
2124 nl_dump_check_consistent(cb, nlh);
2125
2126 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2127
2128 if (sk_filter(sk, skb))
2129 kfree_skb(skb);
2130 else
2131 __netlink_sendskb(sk, skb);
2132
2133 if (cb->done)
2134 cb->done(cb);
2135
2136 nlk->cb_running = false;
2137 mutex_unlock(nlk->cb_mutex);
2138 module_put(cb->module);
2139 consume_skb(cb->skb);
2140 return 0;
2141
2142errout_skb:
2143 mutex_unlock(nlk->cb_mutex);
2144 kfree_skb(skb);
2145 return err;
2146}
2147
2148int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2149 const struct nlmsghdr *nlh,
2150 struct netlink_dump_control *control)
2151{
2152 struct netlink_callback *cb;
2153 struct sock *sk;
2154 struct netlink_sock *nlk;
2155 int ret;
2156
2157 atomic_inc(&skb->users);
2158
2159 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2160 if (sk == NULL) {
2161 ret = -ECONNREFUSED;
2162 goto error_free;
2163 }
2164
2165 nlk = nlk_sk(sk);
2166 mutex_lock(nlk->cb_mutex);
2167 /* A dump is in progress... */
2168 if (nlk->cb_running) {
2169 ret = -EBUSY;
2170 goto error_unlock;
2171 }
2172 /* add reference of module which cb->dump belongs to */
2173 if (!try_module_get(control->module)) {
2174 ret = -EPROTONOSUPPORT;
2175 goto error_unlock;
2176 }
2177
2178 cb = &nlk->cb;
2179 memset(cb, 0, sizeof(*cb));
2180 cb->start = control->start;
2181 cb->dump = control->dump;
2182 cb->done = control->done;
2183 cb->nlh = nlh;
2184 cb->data = control->data;
2185 cb->module = control->module;
2186 cb->min_dump_alloc = control->min_dump_alloc;
2187 cb->skb = skb;
2188
2189 nlk->cb_running = true;
2190
2191 mutex_unlock(nlk->cb_mutex);
2192
2193 if (cb->start)
2194 cb->start(cb);
2195
2196 ret = netlink_dump(sk);
2197 sock_put(sk);
2198
2199 if (ret)
2200 return ret;
2201
2202 /* We successfully started a dump, by returning -EINTR we
2203 * signal not to send ACK even if it was requested.
2204 */
2205 return -EINTR;
2206
2207error_unlock:
2208 sock_put(sk);
2209 mutex_unlock(nlk->cb_mutex);
2210error_free:
2211 kfree_skb(skb);
2212 return ret;
2213}
2214EXPORT_SYMBOL(__netlink_dump_start);
2215
2216void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2217{
2218 struct sk_buff *skb;
2219 struct nlmsghdr *rep;
2220 struct nlmsgerr *errmsg;
2221 size_t payload = sizeof(*errmsg);
2222 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2223
2224 /* Error messages get the original request appened, unless the user
2225 * requests to cap the error message.
2226 */
2227 if (!(nlk->flags & NETLINK_F_CAP_ACK) && err)
2228 payload += nlmsg_len(nlh);
2229
2230 skb = nlmsg_new(payload, GFP_KERNEL);
2231 if (!skb) {
2232 struct sock *sk;
2233
2234 sk = netlink_lookup(sock_net(in_skb->sk),
2235 in_skb->sk->sk_protocol,
2236 NETLINK_CB(in_skb).portid);
2237 if (sk) {
2238 sk->sk_err = ENOBUFS;
2239 sk->sk_error_report(sk);
2240 sock_put(sk);
2241 }
2242 return;
2243 }
2244
2245 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2246 NLMSG_ERROR, payload, 0);
2247 errmsg = nlmsg_data(rep);
2248 errmsg->error = err;
2249 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2250 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2251}
2252EXPORT_SYMBOL(netlink_ack);
2253
2254int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2255 struct nlmsghdr *))
2256{
2257 struct nlmsghdr *nlh;
2258 int err;
2259
2260 while (skb->len >= nlmsg_total_size(0)) {
2261 int msglen;
2262
2263 nlh = nlmsg_hdr(skb);
2264 err = 0;
2265
2266 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2267 return 0;
2268
2269 /* Only requests are handled by the kernel */
2270 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2271 goto ack;
2272
2273 /* Skip control messages */
2274 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2275 goto ack;
2276
2277 err = cb(skb, nlh);
2278 if (err == -EINTR)
2279 goto skip;
2280
2281ack:
2282 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2283 netlink_ack(skb, nlh, err);
2284
2285skip:
2286 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2287 if (msglen > skb->len)
2288 msglen = skb->len;
2289 skb_pull(skb, msglen);
2290 }
2291
2292 return 0;
2293}
2294EXPORT_SYMBOL(netlink_rcv_skb);
2295
2296/**
2297 * nlmsg_notify - send a notification netlink message
2298 * @sk: netlink socket to use
2299 * @skb: notification message
2300 * @portid: destination netlink portid for reports or 0
2301 * @group: destination multicast group or 0
2302 * @report: 1 to report back, 0 to disable
2303 * @flags: allocation flags
2304 */
2305int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2306 unsigned int group, int report, gfp_t flags)
2307{
2308 int err = 0;
2309
2310 if (group) {
2311 int exclude_portid = 0;
2312
2313 if (report) {
2314 atomic_inc(&skb->users);
2315 exclude_portid = portid;
2316 }
2317
2318 /* errors reported via destination sk->sk_err, but propagate
2319 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2320 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2321 }
2322
2323 if (report) {
2324 int err2;
2325
2326 err2 = nlmsg_unicast(sk, skb, portid);
2327 if (!err || err == -ESRCH)
2328 err = err2;
2329 }
2330
2331 return err;
2332}
2333EXPORT_SYMBOL(nlmsg_notify);
2334
2335#ifdef CONFIG_PROC_FS
2336struct nl_seq_iter {
2337 struct seq_net_private p;
2338 struct rhashtable_iter hti;
2339 int link;
2340};
2341
2342static int netlink_walk_start(struct nl_seq_iter *iter)
2343{
2344 int err;
2345
2346 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti);
2347 if (err) {
2348 iter->link = MAX_LINKS;
2349 return err;
2350 }
2351
2352 err = rhashtable_walk_start(&iter->hti);
2353 return err == -EAGAIN ? 0 : err;
2354}
2355
2356static void netlink_walk_stop(struct nl_seq_iter *iter)
2357{
2358 rhashtable_walk_stop(&iter->hti);
2359 rhashtable_walk_exit(&iter->hti);
2360}
2361
2362static void *__netlink_seq_next(struct seq_file *seq)
2363{
2364 struct nl_seq_iter *iter = seq->private;
2365 struct netlink_sock *nlk;
2366
2367 do {
2368 for (;;) {
2369 int err;
2370
2371 nlk = rhashtable_walk_next(&iter->hti);
2372
2373 if (IS_ERR(nlk)) {
2374 if (PTR_ERR(nlk) == -EAGAIN)
2375 continue;
2376
2377 return nlk;
2378 }
2379
2380 if (nlk)
2381 break;
2382
2383 netlink_walk_stop(iter);
2384 if (++iter->link >= MAX_LINKS)
2385 return NULL;
2386
2387 err = netlink_walk_start(iter);
2388 if (err)
2389 return ERR_PTR(err);
2390 }
2391 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2392
2393 return nlk;
2394}
2395
2396static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2397{
2398 struct nl_seq_iter *iter = seq->private;
2399 void *obj = SEQ_START_TOKEN;
2400 loff_t pos;
2401 int err;
2402
2403 iter->link = 0;
2404
2405 err = netlink_walk_start(iter);
2406 if (err)
2407 return ERR_PTR(err);
2408
2409 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2410 obj = __netlink_seq_next(seq);
2411
2412 return obj;
2413}
2414
2415static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2416{
2417 ++*pos;
2418 return __netlink_seq_next(seq);
2419}
2420
2421static void netlink_seq_stop(struct seq_file *seq, void *v)
2422{
2423 struct nl_seq_iter *iter = seq->private;
2424
2425 if (iter->link >= MAX_LINKS)
2426 return;
2427
2428 netlink_walk_stop(iter);
2429}
2430
2431
2432static int netlink_seq_show(struct seq_file *seq, void *v)
2433{
2434 if (v == SEQ_START_TOKEN) {
2435 seq_puts(seq,
2436 "sk Eth Pid Groups "
2437 "Rmem Wmem Dump Locks Drops Inode\n");
2438 } else {
2439 struct sock *s = v;
2440 struct netlink_sock *nlk = nlk_sk(s);
2441
2442 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2443 s,
2444 s->sk_protocol,
2445 nlk->portid,
2446 nlk->groups ? (u32)nlk->groups[0] : 0,
2447 sk_rmem_alloc_get(s),
2448 sk_wmem_alloc_get(s),
2449 nlk->cb_running,
2450 atomic_read(&s->sk_refcnt),
2451 atomic_read(&s->sk_drops),
2452 sock_i_ino(s)
2453 );
2454
2455 }
2456 return 0;
2457}
2458
2459static const struct seq_operations netlink_seq_ops = {
2460 .start = netlink_seq_start,
2461 .next = netlink_seq_next,
2462 .stop = netlink_seq_stop,
2463 .show = netlink_seq_show,
2464};
2465
2466
2467static int netlink_seq_open(struct inode *inode, struct file *file)
2468{
2469 return seq_open_net(inode, file, &netlink_seq_ops,
2470 sizeof(struct nl_seq_iter));
2471}
2472
2473static const struct file_operations netlink_seq_fops = {
2474 .owner = THIS_MODULE,
2475 .open = netlink_seq_open,
2476 .read = seq_read,
2477 .llseek = seq_lseek,
2478 .release = seq_release_net,
2479};
2480
2481#endif
2482
2483int netlink_register_notifier(struct notifier_block *nb)
2484{
2485 return atomic_notifier_chain_register(&netlink_chain, nb);
2486}
2487EXPORT_SYMBOL(netlink_register_notifier);
2488
2489int netlink_unregister_notifier(struct notifier_block *nb)
2490{
2491 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2492}
2493EXPORT_SYMBOL(netlink_unregister_notifier);
2494
2495static const struct proto_ops netlink_ops = {
2496 .family = PF_NETLINK,
2497 .owner = THIS_MODULE,
2498 .release = netlink_release,
2499 .bind = netlink_bind,
2500 .connect = netlink_connect,
2501 .socketpair = sock_no_socketpair,
2502 .accept = sock_no_accept,
2503 .getname = netlink_getname,
2504 .poll = datagram_poll,
2505 .ioctl = netlink_ioctl,
2506 .listen = sock_no_listen,
2507 .shutdown = sock_no_shutdown,
2508 .setsockopt = netlink_setsockopt,
2509 .getsockopt = netlink_getsockopt,
2510 .sendmsg = netlink_sendmsg,
2511 .recvmsg = netlink_recvmsg,
2512 .mmap = sock_no_mmap,
2513 .sendpage = sock_no_sendpage,
2514};
2515
2516static const struct net_proto_family netlink_family_ops = {
2517 .family = PF_NETLINK,
2518 .create = netlink_create,
2519 .owner = THIS_MODULE, /* for consistency 8) */
2520};
2521
2522static int __net_init netlink_net_init(struct net *net)
2523{
2524#ifdef CONFIG_PROC_FS
2525 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
2526 return -ENOMEM;
2527#endif
2528 return 0;
2529}
2530
2531static void __net_exit netlink_net_exit(struct net *net)
2532{
2533#ifdef CONFIG_PROC_FS
2534 remove_proc_entry("netlink", net->proc_net);
2535#endif
2536}
2537
2538static void __init netlink_add_usersock_entry(void)
2539{
2540 struct listeners *listeners;
2541 int groups = 32;
2542
2543 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2544 if (!listeners)
2545 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2546
2547 netlink_table_grab();
2548
2549 nl_table[NETLINK_USERSOCK].groups = groups;
2550 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2551 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2552 nl_table[NETLINK_USERSOCK].registered = 1;
2553 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2554
2555 netlink_table_ungrab();
2556}
2557
2558static struct pernet_operations __net_initdata netlink_net_ops = {
2559 .init = netlink_net_init,
2560 .exit = netlink_net_exit,
2561};
2562
2563static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2564{
2565 const struct netlink_sock *nlk = data;
2566 struct netlink_compare_arg arg;
2567
2568 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2569 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2570}
2571
2572static const struct rhashtable_params netlink_rhashtable_params = {
2573 .head_offset = offsetof(struct netlink_sock, node),
2574 .key_len = netlink_compare_arg_len,
2575 .obj_hashfn = netlink_hash,
2576 .obj_cmpfn = netlink_compare,
2577 .automatic_shrinking = true,
2578};
2579
2580static int __init netlink_proto_init(void)
2581{
2582 int i;
2583 int err = proto_register(&netlink_proto, 0);
2584
2585 if (err != 0)
2586 goto out;
2587
2588 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2589
2590 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2591 if (!nl_table)
2592 goto panic;
2593
2594 for (i = 0; i < MAX_LINKS; i++) {
2595 if (rhashtable_init(&nl_table[i].hash,
2596 &netlink_rhashtable_params) < 0) {
2597 while (--i > 0)
2598 rhashtable_destroy(&nl_table[i].hash);
2599 kfree(nl_table);
2600 goto panic;
2601 }
2602 }
2603
2604 INIT_LIST_HEAD(&netlink_tap_all);
2605
2606 netlink_add_usersock_entry();
2607
2608 sock_register(&netlink_family_ops);
2609 register_pernet_subsys(&netlink_net_ops);
2610 /* The netlink device handler may be needed early. */
2611 rtnetlink_init();
2612out:
2613 return err;
2614panic:
2615 panic("netlink_init: Cannot allocate nl_table\n");
2616}
2617
2618core_initcall(netlink_proto_init);