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Merge tag 'iommu-updates-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git...
[mirror_ubuntu-artful-kernel.git] / net / netlink / af_netlink.c
1 /*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 * Patrick McHardy <kaber@trash.net>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 *
13 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
14 * added netlink_proto_exit
15 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
16 * use nlk_sk, as sk->protinfo is on a diet 8)
17 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
18 * - inc module use count of module that owns
19 * the kernel socket in case userspace opens
20 * socket of same protocol
21 * - remove all module support, since netlink is
22 * mandatory if CONFIG_NET=y these days
23 */
24
25 #include <linux/module.h>
26
27 #include <linux/capability.h>
28 #include <linux/kernel.h>
29 #include <linux/init.h>
30 #include <linux/signal.h>
31 #include <linux/sched.h>
32 #include <linux/errno.h>
33 #include <linux/string.h>
34 #include <linux/stat.h>
35 #include <linux/socket.h>
36 #include <linux/un.h>
37 #include <linux/fcntl.h>
38 #include <linux/termios.h>
39 #include <linux/sockios.h>
40 #include <linux/net.h>
41 #include <linux/fs.h>
42 #include <linux/slab.h>
43 #include <linux/uaccess.h>
44 #include <linux/skbuff.h>
45 #include <linux/netdevice.h>
46 #include <linux/rtnetlink.h>
47 #include <linux/proc_fs.h>
48 #include <linux/seq_file.h>
49 #include <linux/notifier.h>
50 #include <linux/security.h>
51 #include <linux/jhash.h>
52 #include <linux/jiffies.h>
53 #include <linux/random.h>
54 #include <linux/bitops.h>
55 #include <linux/mm.h>
56 #include <linux/types.h>
57 #include <linux/audit.h>
58 #include <linux/mutex.h>
59 #include <linux/vmalloc.h>
60 #include <linux/if_arp.h>
61 #include <linux/rhashtable.h>
62 #include <asm/cacheflush.h>
63 #include <linux/hash.h>
64 #include <linux/genetlink.h>
65 #include <linux/net_namespace.h>
66
67 #include <net/net_namespace.h>
68 #include <net/sock.h>
69 #include <net/scm.h>
70 #include <net/netlink.h>
71
72 #include "af_netlink.h"
73
74 struct listeners {
75 struct rcu_head rcu;
76 unsigned long masks[0];
77 };
78
79 /* state bits */
80 #define NETLINK_S_CONGESTED 0x0
81
82 static inline int netlink_is_kernel(struct sock *sk)
83 {
84 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;
85 }
86
87 struct netlink_table *nl_table __read_mostly;
88 EXPORT_SYMBOL_GPL(nl_table);
89
90 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
91
92 static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
93
94 static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
95 "nlk_cb_mutex-ROUTE",
96 "nlk_cb_mutex-1",
97 "nlk_cb_mutex-USERSOCK",
98 "nlk_cb_mutex-FIREWALL",
99 "nlk_cb_mutex-SOCK_DIAG",
100 "nlk_cb_mutex-NFLOG",
101 "nlk_cb_mutex-XFRM",
102 "nlk_cb_mutex-SELINUX",
103 "nlk_cb_mutex-ISCSI",
104 "nlk_cb_mutex-AUDIT",
105 "nlk_cb_mutex-FIB_LOOKUP",
106 "nlk_cb_mutex-CONNECTOR",
107 "nlk_cb_mutex-NETFILTER",
108 "nlk_cb_mutex-IP6_FW",
109 "nlk_cb_mutex-DNRTMSG",
110 "nlk_cb_mutex-KOBJECT_UEVENT",
111 "nlk_cb_mutex-GENERIC",
112 "nlk_cb_mutex-17",
113 "nlk_cb_mutex-SCSITRANSPORT",
114 "nlk_cb_mutex-ECRYPTFS",
115 "nlk_cb_mutex-RDMA",
116 "nlk_cb_mutex-CRYPTO",
117 "nlk_cb_mutex-SMC",
118 "nlk_cb_mutex-23",
119 "nlk_cb_mutex-24",
120 "nlk_cb_mutex-25",
121 "nlk_cb_mutex-26",
122 "nlk_cb_mutex-27",
123 "nlk_cb_mutex-28",
124 "nlk_cb_mutex-29",
125 "nlk_cb_mutex-30",
126 "nlk_cb_mutex-31",
127 "nlk_cb_mutex-MAX_LINKS"
128 };
129
130 static int netlink_dump(struct sock *sk);
131 static void netlink_skb_destructor(struct sk_buff *skb);
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 */
141 DEFINE_RWLOCK(nl_table_lock);
142 EXPORT_SYMBOL_GPL(nl_table_lock);
143 static 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
147 static BLOCKING_NOTIFIER_HEAD(netlink_chain);
148
149 static DEFINE_SPINLOCK(netlink_tap_lock);
150 static struct list_head netlink_tap_all __read_mostly;
151
152 static const struct rhashtable_params netlink_rhashtable_params;
153
154 static inline u32 netlink_group_mask(u32 group)
155 {
156 return group ? 1 << (group - 1) : 0;
157 }
158
159 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
160 gfp_t gfp_mask)
161 {
162 unsigned int len = skb_end_offset(skb);
163 struct sk_buff *new;
164
165 new = alloc_skb(len, gfp_mask);
166 if (new == NULL)
167 return NULL;
168
169 NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
170 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
171 NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
172
173 skb_put_data(new, skb->data, len);
174 return new;
175 }
176
177 int netlink_add_tap(struct netlink_tap *nt)
178 {
179 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
180 return -EINVAL;
181
182 spin_lock(&netlink_tap_lock);
183 list_add_rcu(&nt->list, &netlink_tap_all);
184 spin_unlock(&netlink_tap_lock);
185
186 __module_get(nt->module);
187
188 return 0;
189 }
190 EXPORT_SYMBOL_GPL(netlink_add_tap);
191
192 static int __netlink_remove_tap(struct netlink_tap *nt)
193 {
194 bool found = false;
195 struct netlink_tap *tmp;
196
197 spin_lock(&netlink_tap_lock);
198
199 list_for_each_entry(tmp, &netlink_tap_all, list) {
200 if (nt == tmp) {
201 list_del_rcu(&nt->list);
202 found = true;
203 goto out;
204 }
205 }
206
207 pr_warn("__netlink_remove_tap: %p not found\n", nt);
208 out:
209 spin_unlock(&netlink_tap_lock);
210
211 if (found)
212 module_put(nt->module);
213
214 return found ? 0 : -ENODEV;
215 }
216
217 int netlink_remove_tap(struct netlink_tap *nt)
218 {
219 int ret;
220
221 ret = __netlink_remove_tap(nt);
222 synchronize_net();
223
224 return ret;
225 }
226 EXPORT_SYMBOL_GPL(netlink_remove_tap);
227
228 static bool netlink_filter_tap(const struct sk_buff *skb)
229 {
230 struct sock *sk = skb->sk;
231
232 /* We take the more conservative approach and
233 * whitelist socket protocols that may pass.
234 */
235 switch (sk->sk_protocol) {
236 case NETLINK_ROUTE:
237 case NETLINK_USERSOCK:
238 case NETLINK_SOCK_DIAG:
239 case NETLINK_NFLOG:
240 case NETLINK_XFRM:
241 case NETLINK_FIB_LOOKUP:
242 case NETLINK_NETFILTER:
243 case NETLINK_GENERIC:
244 return true;
245 }
246
247 return false;
248 }
249
250 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
251 struct net_device *dev)
252 {
253 struct sk_buff *nskb;
254 struct sock *sk = skb->sk;
255 int ret = -ENOMEM;
256
257 dev_hold(dev);
258
259 if (is_vmalloc_addr(skb->head))
260 nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
261 else
262 nskb = skb_clone(skb, GFP_ATOMIC);
263 if (nskb) {
264 nskb->dev = dev;
265 nskb->protocol = htons((u16) sk->sk_protocol);
266 nskb->pkt_type = netlink_is_kernel(sk) ?
267 PACKET_KERNEL : PACKET_USER;
268 skb_reset_network_header(nskb);
269 ret = dev_queue_xmit(nskb);
270 if (unlikely(ret > 0))
271 ret = net_xmit_errno(ret);
272 }
273
274 dev_put(dev);
275 return ret;
276 }
277
278 static void __netlink_deliver_tap(struct sk_buff *skb)
279 {
280 int ret;
281 struct netlink_tap *tmp;
282
283 if (!netlink_filter_tap(skb))
284 return;
285
286 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
287 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
288 if (unlikely(ret))
289 break;
290 }
291 }
292
293 static void netlink_deliver_tap(struct sk_buff *skb)
294 {
295 rcu_read_lock();
296
297 if (unlikely(!list_empty(&netlink_tap_all)))
298 __netlink_deliver_tap(skb);
299
300 rcu_read_unlock();
301 }
302
303 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
304 struct sk_buff *skb)
305 {
306 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
307 netlink_deliver_tap(skb);
308 }
309
310 static void netlink_overrun(struct sock *sk)
311 {
312 struct netlink_sock *nlk = nlk_sk(sk);
313
314 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
315 if (!test_and_set_bit(NETLINK_S_CONGESTED,
316 &nlk_sk(sk)->state)) {
317 sk->sk_err = ENOBUFS;
318 sk->sk_error_report(sk);
319 }
320 }
321 atomic_inc(&sk->sk_drops);
322 }
323
324 static void netlink_rcv_wake(struct sock *sk)
325 {
326 struct netlink_sock *nlk = nlk_sk(sk);
327
328 if (skb_queue_empty(&sk->sk_receive_queue))
329 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
330 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
331 wake_up_interruptible(&nlk->wait);
332 }
333
334 static void netlink_skb_destructor(struct sk_buff *skb)
335 {
336 if (is_vmalloc_addr(skb->head)) {
337 if (!skb->cloned ||
338 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
339 vfree(skb->head);
340
341 skb->head = NULL;
342 }
343 if (skb->sk != NULL)
344 sock_rfree(skb);
345 }
346
347 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
348 {
349 WARN_ON(skb->sk != NULL);
350 skb->sk = sk;
351 skb->destructor = netlink_skb_destructor;
352 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
353 sk_mem_charge(sk, skb->truesize);
354 }
355
356 static void netlink_sock_destruct(struct sock *sk)
357 {
358 struct netlink_sock *nlk = nlk_sk(sk);
359
360 if (nlk->cb_running) {
361 if (nlk->cb.done)
362 nlk->cb.done(&nlk->cb);
363 module_put(nlk->cb.module);
364 kfree_skb(nlk->cb.skb);
365 }
366
367 skb_queue_purge(&sk->sk_receive_queue);
368
369 if (!sock_flag(sk, SOCK_DEAD)) {
370 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
371 return;
372 }
373
374 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
375 WARN_ON(refcount_read(&sk->sk_wmem_alloc));
376 WARN_ON(nlk_sk(sk)->groups);
377 }
378
379 static void netlink_sock_destruct_work(struct work_struct *work)
380 {
381 struct netlink_sock *nlk = container_of(work, struct netlink_sock,
382 work);
383
384 sk_free(&nlk->sk);
385 }
386
387 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
388 * SMP. Look, when several writers sleep and reader wakes them up, all but one
389 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
390 * this, _but_ remember, it adds useless work on UP machines.
391 */
392
393 void netlink_table_grab(void)
394 __acquires(nl_table_lock)
395 {
396 might_sleep();
397
398 write_lock_irq(&nl_table_lock);
399
400 if (atomic_read(&nl_table_users)) {
401 DECLARE_WAITQUEUE(wait, current);
402
403 add_wait_queue_exclusive(&nl_table_wait, &wait);
404 for (;;) {
405 set_current_state(TASK_UNINTERRUPTIBLE);
406 if (atomic_read(&nl_table_users) == 0)
407 break;
408 write_unlock_irq(&nl_table_lock);
409 schedule();
410 write_lock_irq(&nl_table_lock);
411 }
412
413 __set_current_state(TASK_RUNNING);
414 remove_wait_queue(&nl_table_wait, &wait);
415 }
416 }
417
418 void netlink_table_ungrab(void)
419 __releases(nl_table_lock)
420 {
421 write_unlock_irq(&nl_table_lock);
422 wake_up(&nl_table_wait);
423 }
424
425 static inline void
426 netlink_lock_table(void)
427 {
428 /* read_lock() synchronizes us to netlink_table_grab */
429
430 read_lock(&nl_table_lock);
431 atomic_inc(&nl_table_users);
432 read_unlock(&nl_table_lock);
433 }
434
435 static inline void
436 netlink_unlock_table(void)
437 {
438 if (atomic_dec_and_test(&nl_table_users))
439 wake_up(&nl_table_wait);
440 }
441
442 struct netlink_compare_arg
443 {
444 possible_net_t pnet;
445 u32 portid;
446 };
447
448 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
449 #define netlink_compare_arg_len \
450 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
451
452 static inline int netlink_compare(struct rhashtable_compare_arg *arg,
453 const void *ptr)
454 {
455 const struct netlink_compare_arg *x = arg->key;
456 const struct netlink_sock *nlk = ptr;
457
458 return nlk->portid != x->portid ||
459 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
460 }
461
462 static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
463 struct net *net, u32 portid)
464 {
465 memset(arg, 0, sizeof(*arg));
466 write_pnet(&arg->pnet, net);
467 arg->portid = portid;
468 }
469
470 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
471 struct net *net)
472 {
473 struct netlink_compare_arg arg;
474
475 netlink_compare_arg_init(&arg, net, portid);
476 return rhashtable_lookup_fast(&table->hash, &arg,
477 netlink_rhashtable_params);
478 }
479
480 static int __netlink_insert(struct netlink_table *table, struct sock *sk)
481 {
482 struct netlink_compare_arg arg;
483
484 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
485 return rhashtable_lookup_insert_key(&table->hash, &arg,
486 &nlk_sk(sk)->node,
487 netlink_rhashtable_params);
488 }
489
490 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
491 {
492 struct netlink_table *table = &nl_table[protocol];
493 struct sock *sk;
494
495 rcu_read_lock();
496 sk = __netlink_lookup(table, portid, net);
497 if (sk)
498 sock_hold(sk);
499 rcu_read_unlock();
500
501 return sk;
502 }
503
504 static const struct proto_ops netlink_ops;
505
506 static void
507 netlink_update_listeners(struct sock *sk)
508 {
509 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
510 unsigned long mask;
511 unsigned int i;
512 struct listeners *listeners;
513
514 listeners = nl_deref_protected(tbl->listeners);
515 if (!listeners)
516 return;
517
518 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
519 mask = 0;
520 sk_for_each_bound(sk, &tbl->mc_list) {
521 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
522 mask |= nlk_sk(sk)->groups[i];
523 }
524 listeners->masks[i] = mask;
525 }
526 /* this function is only called with the netlink table "grabbed", which
527 * makes sure updates are visible before bind or setsockopt return. */
528 }
529
530 static int netlink_insert(struct sock *sk, u32 portid)
531 {
532 struct netlink_table *table = &nl_table[sk->sk_protocol];
533 int err;
534
535 lock_sock(sk);
536
537 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
538 if (nlk_sk(sk)->bound)
539 goto err;
540
541 err = -ENOMEM;
542 if (BITS_PER_LONG > 32 &&
543 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
544 goto err;
545
546 nlk_sk(sk)->portid = portid;
547 sock_hold(sk);
548
549 err = __netlink_insert(table, sk);
550 if (err) {
551 /* In case the hashtable backend returns with -EBUSY
552 * from here, it must not escape to the caller.
553 */
554 if (unlikely(err == -EBUSY))
555 err = -EOVERFLOW;
556 if (err == -EEXIST)
557 err = -EADDRINUSE;
558 sock_put(sk);
559 goto err;
560 }
561
562 /* We need to ensure that the socket is hashed and visible. */
563 smp_wmb();
564 nlk_sk(sk)->bound = portid;
565
566 err:
567 release_sock(sk);
568 return err;
569 }
570
571 static void netlink_remove(struct sock *sk)
572 {
573 struct netlink_table *table;
574
575 table = &nl_table[sk->sk_protocol];
576 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
577 netlink_rhashtable_params)) {
578 WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
579 __sock_put(sk);
580 }
581
582 netlink_table_grab();
583 if (nlk_sk(sk)->subscriptions) {
584 __sk_del_bind_node(sk);
585 netlink_update_listeners(sk);
586 }
587 if (sk->sk_protocol == NETLINK_GENERIC)
588 atomic_inc(&genl_sk_destructing_cnt);
589 netlink_table_ungrab();
590 }
591
592 static struct proto netlink_proto = {
593 .name = "NETLINK",
594 .owner = THIS_MODULE,
595 .obj_size = sizeof(struct netlink_sock),
596 };
597
598 static int __netlink_create(struct net *net, struct socket *sock,
599 struct mutex *cb_mutex, int protocol,
600 int kern)
601 {
602 struct sock *sk;
603 struct netlink_sock *nlk;
604
605 sock->ops = &netlink_ops;
606
607 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
608 if (!sk)
609 return -ENOMEM;
610
611 sock_init_data(sock, sk);
612
613 nlk = nlk_sk(sk);
614 if (cb_mutex) {
615 nlk->cb_mutex = cb_mutex;
616 } else {
617 nlk->cb_mutex = &nlk->cb_def_mutex;
618 mutex_init(nlk->cb_mutex);
619 lockdep_set_class_and_name(nlk->cb_mutex,
620 nlk_cb_mutex_keys + protocol,
621 nlk_cb_mutex_key_strings[protocol]);
622 }
623 init_waitqueue_head(&nlk->wait);
624
625 sk->sk_destruct = netlink_sock_destruct;
626 sk->sk_protocol = protocol;
627 return 0;
628 }
629
630 static int netlink_create(struct net *net, struct socket *sock, int protocol,
631 int kern)
632 {
633 struct module *module = NULL;
634 struct mutex *cb_mutex;
635 struct netlink_sock *nlk;
636 int (*bind)(struct net *net, int group);
637 void (*unbind)(struct net *net, int group);
638 int err = 0;
639
640 sock->state = SS_UNCONNECTED;
641
642 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
643 return -ESOCKTNOSUPPORT;
644
645 if (protocol < 0 || protocol >= MAX_LINKS)
646 return -EPROTONOSUPPORT;
647
648 netlink_lock_table();
649 #ifdef CONFIG_MODULES
650 if (!nl_table[protocol].registered) {
651 netlink_unlock_table();
652 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
653 netlink_lock_table();
654 }
655 #endif
656 if (nl_table[protocol].registered &&
657 try_module_get(nl_table[protocol].module))
658 module = nl_table[protocol].module;
659 else
660 err = -EPROTONOSUPPORT;
661 cb_mutex = nl_table[protocol].cb_mutex;
662 bind = nl_table[protocol].bind;
663 unbind = nl_table[protocol].unbind;
664 netlink_unlock_table();
665
666 if (err < 0)
667 goto out;
668
669 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
670 if (err < 0)
671 goto out_module;
672
673 local_bh_disable();
674 sock_prot_inuse_add(net, &netlink_proto, 1);
675 local_bh_enable();
676
677 nlk = nlk_sk(sock->sk);
678 nlk->module = module;
679 nlk->netlink_bind = bind;
680 nlk->netlink_unbind = unbind;
681 out:
682 return err;
683
684 out_module:
685 module_put(module);
686 goto out;
687 }
688
689 static void deferred_put_nlk_sk(struct rcu_head *head)
690 {
691 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
692 struct sock *sk = &nlk->sk;
693
694 if (!refcount_dec_and_test(&sk->sk_refcnt))
695 return;
696
697 if (nlk->cb_running && nlk->cb.done) {
698 INIT_WORK(&nlk->work, netlink_sock_destruct_work);
699 schedule_work(&nlk->work);
700 return;
701 }
702
703 sk_free(sk);
704 }
705
706 static int netlink_release(struct socket *sock)
707 {
708 struct sock *sk = sock->sk;
709 struct netlink_sock *nlk;
710
711 if (!sk)
712 return 0;
713
714 netlink_remove(sk);
715 sock_orphan(sk);
716 nlk = nlk_sk(sk);
717
718 /*
719 * OK. Socket is unlinked, any packets that arrive now
720 * will be purged.
721 */
722
723 /* must not acquire netlink_table_lock in any way again before unbind
724 * and notifying genetlink is done as otherwise it might deadlock
725 */
726 if (nlk->netlink_unbind) {
727 int i;
728
729 for (i = 0; i < nlk->ngroups; i++)
730 if (test_bit(i, nlk->groups))
731 nlk->netlink_unbind(sock_net(sk), i + 1);
732 }
733 if (sk->sk_protocol == NETLINK_GENERIC &&
734 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
735 wake_up(&genl_sk_destructing_waitq);
736
737 sock->sk = NULL;
738 wake_up_interruptible_all(&nlk->wait);
739
740 skb_queue_purge(&sk->sk_write_queue);
741
742 if (nlk->portid && nlk->bound) {
743 struct netlink_notify n = {
744 .net = sock_net(sk),
745 .protocol = sk->sk_protocol,
746 .portid = nlk->portid,
747 };
748 blocking_notifier_call_chain(&netlink_chain,
749 NETLINK_URELEASE, &n);
750 }
751
752 module_put(nlk->module);
753
754 if (netlink_is_kernel(sk)) {
755 netlink_table_grab();
756 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
757 if (--nl_table[sk->sk_protocol].registered == 0) {
758 struct listeners *old;
759
760 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
761 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
762 kfree_rcu(old, rcu);
763 nl_table[sk->sk_protocol].module = NULL;
764 nl_table[sk->sk_protocol].bind = NULL;
765 nl_table[sk->sk_protocol].unbind = NULL;
766 nl_table[sk->sk_protocol].flags = 0;
767 nl_table[sk->sk_protocol].registered = 0;
768 }
769 netlink_table_ungrab();
770 }
771
772 kfree(nlk->groups);
773 nlk->groups = NULL;
774
775 local_bh_disable();
776 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
777 local_bh_enable();
778 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
779 return 0;
780 }
781
782 static int netlink_autobind(struct socket *sock)
783 {
784 struct sock *sk = sock->sk;
785 struct net *net = sock_net(sk);
786 struct netlink_table *table = &nl_table[sk->sk_protocol];
787 s32 portid = task_tgid_vnr(current);
788 int err;
789 s32 rover = -4096;
790 bool ok;
791
792 retry:
793 cond_resched();
794 rcu_read_lock();
795 ok = !__netlink_lookup(table, portid, net);
796 rcu_read_unlock();
797 if (!ok) {
798 /* Bind collision, search negative portid values. */
799 if (rover == -4096)
800 /* rover will be in range [S32_MIN, -4097] */
801 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
802 else if (rover >= -4096)
803 rover = -4097;
804 portid = rover--;
805 goto retry;
806 }
807
808 err = netlink_insert(sk, portid);
809 if (err == -EADDRINUSE)
810 goto retry;
811
812 /* If 2 threads race to autobind, that is fine. */
813 if (err == -EBUSY)
814 err = 0;
815
816 return err;
817 }
818
819 /**
820 * __netlink_ns_capable - General netlink message capability test
821 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
822 * @user_ns: The user namespace of the capability to use
823 * @cap: The capability to use
824 *
825 * Test to see if the opener of the socket we received the message
826 * from had when the netlink socket was created and the sender of the
827 * message has has the capability @cap in the user namespace @user_ns.
828 */
829 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
830 struct user_namespace *user_ns, int cap)
831 {
832 return ((nsp->flags & NETLINK_SKB_DST) ||
833 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
834 ns_capable(user_ns, cap);
835 }
836 EXPORT_SYMBOL(__netlink_ns_capable);
837
838 /**
839 * netlink_ns_capable - General netlink message capability test
840 * @skb: socket buffer holding a netlink command from userspace
841 * @user_ns: The user namespace of the capability to use
842 * @cap: The capability to use
843 *
844 * Test to see if the opener of the socket we received the message
845 * from had when the netlink socket was created and the sender of the
846 * message has has the capability @cap in the user namespace @user_ns.
847 */
848 bool netlink_ns_capable(const struct sk_buff *skb,
849 struct user_namespace *user_ns, int cap)
850 {
851 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
852 }
853 EXPORT_SYMBOL(netlink_ns_capable);
854
855 /**
856 * netlink_capable - Netlink global message capability test
857 * @skb: socket buffer holding a netlink command from userspace
858 * @cap: The capability to use
859 *
860 * Test to see if the opener of the socket we received the message
861 * from had when the netlink socket was created and the sender of the
862 * message has has the capability @cap in all user namespaces.
863 */
864 bool netlink_capable(const struct sk_buff *skb, int cap)
865 {
866 return netlink_ns_capable(skb, &init_user_ns, cap);
867 }
868 EXPORT_SYMBOL(netlink_capable);
869
870 /**
871 * netlink_net_capable - Netlink network namespace message capability test
872 * @skb: socket buffer holding a netlink command from userspace
873 * @cap: The capability to use
874 *
875 * Test to see if the opener of the socket we received the message
876 * from had when the netlink socket was created and the sender of the
877 * message has has the capability @cap over the network namespace of
878 * the socket we received the message from.
879 */
880 bool netlink_net_capable(const struct sk_buff *skb, int cap)
881 {
882 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
883 }
884 EXPORT_SYMBOL(netlink_net_capable);
885
886 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
887 {
888 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
889 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
890 }
891
892 static void
893 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
894 {
895 struct netlink_sock *nlk = nlk_sk(sk);
896
897 if (nlk->subscriptions && !subscriptions)
898 __sk_del_bind_node(sk);
899 else if (!nlk->subscriptions && subscriptions)
900 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
901 nlk->subscriptions = subscriptions;
902 }
903
904 static int netlink_realloc_groups(struct sock *sk)
905 {
906 struct netlink_sock *nlk = nlk_sk(sk);
907 unsigned int groups;
908 unsigned long *new_groups;
909 int err = 0;
910
911 netlink_table_grab();
912
913 groups = nl_table[sk->sk_protocol].groups;
914 if (!nl_table[sk->sk_protocol].registered) {
915 err = -ENOENT;
916 goto out_unlock;
917 }
918
919 if (nlk->ngroups >= groups)
920 goto out_unlock;
921
922 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
923 if (new_groups == NULL) {
924 err = -ENOMEM;
925 goto out_unlock;
926 }
927 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
928 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
929
930 nlk->groups = new_groups;
931 nlk->ngroups = groups;
932 out_unlock:
933 netlink_table_ungrab();
934 return err;
935 }
936
937 static void netlink_undo_bind(int group, long unsigned int groups,
938 struct sock *sk)
939 {
940 struct netlink_sock *nlk = nlk_sk(sk);
941 int undo;
942
943 if (!nlk->netlink_unbind)
944 return;
945
946 for (undo = 0; undo < group; undo++)
947 if (test_bit(undo, &groups))
948 nlk->netlink_unbind(sock_net(sk), undo + 1);
949 }
950
951 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
952 int addr_len)
953 {
954 struct sock *sk = sock->sk;
955 struct net *net = sock_net(sk);
956 struct netlink_sock *nlk = nlk_sk(sk);
957 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
958 int err;
959 long unsigned int groups = nladdr->nl_groups;
960 bool bound;
961
962 if (addr_len < sizeof(struct sockaddr_nl))
963 return -EINVAL;
964
965 if (nladdr->nl_family != AF_NETLINK)
966 return -EINVAL;
967
968 /* Only superuser is allowed to listen multicasts */
969 if (groups) {
970 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
971 return -EPERM;
972 err = netlink_realloc_groups(sk);
973 if (err)
974 return err;
975 }
976
977 bound = nlk->bound;
978 if (bound) {
979 /* Ensure nlk->portid is up-to-date. */
980 smp_rmb();
981
982 if (nladdr->nl_pid != nlk->portid)
983 return -EINVAL;
984 }
985
986 if (nlk->netlink_bind && groups) {
987 int group;
988
989 for (group = 0; group < nlk->ngroups; group++) {
990 if (!test_bit(group, &groups))
991 continue;
992 err = nlk->netlink_bind(net, group + 1);
993 if (!err)
994 continue;
995 netlink_undo_bind(group, groups, sk);
996 return err;
997 }
998 }
999
1000 /* No need for barriers here as we return to user-space without
1001 * using any of the bound attributes.
1002 */
1003 if (!bound) {
1004 err = nladdr->nl_pid ?
1005 netlink_insert(sk, nladdr->nl_pid) :
1006 netlink_autobind(sock);
1007 if (err) {
1008 netlink_undo_bind(nlk->ngroups, groups, sk);
1009 return err;
1010 }
1011 }
1012
1013 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1014 return 0;
1015
1016 netlink_table_grab();
1017 netlink_update_subscriptions(sk, nlk->subscriptions +
1018 hweight32(groups) -
1019 hweight32(nlk->groups[0]));
1020 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1021 netlink_update_listeners(sk);
1022 netlink_table_ungrab();
1023
1024 return 0;
1025 }
1026
1027 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1028 int alen, int flags)
1029 {
1030 int err = 0;
1031 struct sock *sk = sock->sk;
1032 struct netlink_sock *nlk = nlk_sk(sk);
1033 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1034
1035 if (alen < sizeof(addr->sa_family))
1036 return -EINVAL;
1037
1038 if (addr->sa_family == AF_UNSPEC) {
1039 sk->sk_state = NETLINK_UNCONNECTED;
1040 nlk->dst_portid = 0;
1041 nlk->dst_group = 0;
1042 return 0;
1043 }
1044 if (addr->sa_family != AF_NETLINK)
1045 return -EINVAL;
1046
1047 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1048 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1049 return -EPERM;
1050
1051 /* No need for barriers here as we return to user-space without
1052 * using any of the bound attributes.
1053 */
1054 if (!nlk->bound)
1055 err = netlink_autobind(sock);
1056
1057 if (err == 0) {
1058 sk->sk_state = NETLINK_CONNECTED;
1059 nlk->dst_portid = nladdr->nl_pid;
1060 nlk->dst_group = ffs(nladdr->nl_groups);
1061 }
1062
1063 return err;
1064 }
1065
1066 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1067 int *addr_len, int peer)
1068 {
1069 struct sock *sk = sock->sk;
1070 struct netlink_sock *nlk = nlk_sk(sk);
1071 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1072
1073 nladdr->nl_family = AF_NETLINK;
1074 nladdr->nl_pad = 0;
1075 *addr_len = sizeof(*nladdr);
1076
1077 if (peer) {
1078 nladdr->nl_pid = nlk->dst_portid;
1079 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1080 } else {
1081 nladdr->nl_pid = nlk->portid;
1082 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1083 }
1084 return 0;
1085 }
1086
1087 static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1088 unsigned long arg)
1089 {
1090 /* try to hand this ioctl down to the NIC drivers.
1091 */
1092 return -ENOIOCTLCMD;
1093 }
1094
1095 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1096 {
1097 struct sock *sock;
1098 struct netlink_sock *nlk;
1099
1100 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1101 if (!sock)
1102 return ERR_PTR(-ECONNREFUSED);
1103
1104 /* Don't bother queuing skb if kernel socket has no input function */
1105 nlk = nlk_sk(sock);
1106 if (sock->sk_state == NETLINK_CONNECTED &&
1107 nlk->dst_portid != nlk_sk(ssk)->portid) {
1108 sock_put(sock);
1109 return ERR_PTR(-ECONNREFUSED);
1110 }
1111 return sock;
1112 }
1113
1114 struct sock *netlink_getsockbyfilp(struct file *filp)
1115 {
1116 struct inode *inode = file_inode(filp);
1117 struct sock *sock;
1118
1119 if (!S_ISSOCK(inode->i_mode))
1120 return ERR_PTR(-ENOTSOCK);
1121
1122 sock = SOCKET_I(inode)->sk;
1123 if (sock->sk_family != AF_NETLINK)
1124 return ERR_PTR(-EINVAL);
1125
1126 sock_hold(sock);
1127 return sock;
1128 }
1129
1130 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1131 int broadcast)
1132 {
1133 struct sk_buff *skb;
1134 void *data;
1135
1136 if (size <= NLMSG_GOODSIZE || broadcast)
1137 return alloc_skb(size, GFP_KERNEL);
1138
1139 size = SKB_DATA_ALIGN(size) +
1140 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1141
1142 data = vmalloc(size);
1143 if (data == NULL)
1144 return NULL;
1145
1146 skb = __build_skb(data, size);
1147 if (skb == NULL)
1148 vfree(data);
1149 else
1150 skb->destructor = netlink_skb_destructor;
1151
1152 return skb;
1153 }
1154
1155 /*
1156 * Attach a skb to a netlink socket.
1157 * The caller must hold a reference to the destination socket. On error, the
1158 * reference is dropped. The skb is not send to the destination, just all
1159 * all error checks are performed and memory in the queue is reserved.
1160 * Return values:
1161 * < 0: error. skb freed, reference to sock dropped.
1162 * 0: continue
1163 * 1: repeat lookup - reference dropped while waiting for socket memory.
1164 */
1165 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1166 long *timeo, struct sock *ssk)
1167 {
1168 struct netlink_sock *nlk;
1169
1170 nlk = nlk_sk(sk);
1171
1172 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1173 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1174 DECLARE_WAITQUEUE(wait, current);
1175 if (!*timeo) {
1176 if (!ssk || netlink_is_kernel(ssk))
1177 netlink_overrun(sk);
1178 sock_put(sk);
1179 kfree_skb(skb);
1180 return -EAGAIN;
1181 }
1182
1183 __set_current_state(TASK_INTERRUPTIBLE);
1184 add_wait_queue(&nlk->wait, &wait);
1185
1186 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1187 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1188 !sock_flag(sk, SOCK_DEAD))
1189 *timeo = schedule_timeout(*timeo);
1190
1191 __set_current_state(TASK_RUNNING);
1192 remove_wait_queue(&nlk->wait, &wait);
1193 sock_put(sk);
1194
1195 if (signal_pending(current)) {
1196 kfree_skb(skb);
1197 return sock_intr_errno(*timeo);
1198 }
1199 return 1;
1200 }
1201 netlink_skb_set_owner_r(skb, sk);
1202 return 0;
1203 }
1204
1205 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1206 {
1207 int len = skb->len;
1208
1209 netlink_deliver_tap(skb);
1210
1211 skb_queue_tail(&sk->sk_receive_queue, skb);
1212 sk->sk_data_ready(sk);
1213 return len;
1214 }
1215
1216 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1217 {
1218 int len = __netlink_sendskb(sk, skb);
1219
1220 sock_put(sk);
1221 return len;
1222 }
1223
1224 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1225 {
1226 kfree_skb(skb);
1227 sock_put(sk);
1228 }
1229
1230 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1231 {
1232 int delta;
1233
1234 WARN_ON(skb->sk != NULL);
1235 delta = skb->end - skb->tail;
1236 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1237 return skb;
1238
1239 if (skb_shared(skb)) {
1240 struct sk_buff *nskb = skb_clone(skb, allocation);
1241 if (!nskb)
1242 return skb;
1243 consume_skb(skb);
1244 skb = nskb;
1245 }
1246
1247 pskb_expand_head(skb, 0, -delta,
1248 (allocation & ~__GFP_DIRECT_RECLAIM) |
1249 __GFP_NOWARN | __GFP_NORETRY);
1250 return skb;
1251 }
1252
1253 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1254 struct sock *ssk)
1255 {
1256 int ret;
1257 struct netlink_sock *nlk = nlk_sk(sk);
1258
1259 ret = -ECONNREFUSED;
1260 if (nlk->netlink_rcv != NULL) {
1261 ret = skb->len;
1262 netlink_skb_set_owner_r(skb, sk);
1263 NETLINK_CB(skb).sk = ssk;
1264 netlink_deliver_tap_kernel(sk, ssk, skb);
1265 nlk->netlink_rcv(skb);
1266 consume_skb(skb);
1267 } else {
1268 kfree_skb(skb);
1269 }
1270 sock_put(sk);
1271 return ret;
1272 }
1273
1274 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1275 u32 portid, int nonblock)
1276 {
1277 struct sock *sk;
1278 int err;
1279 long timeo;
1280
1281 skb = netlink_trim(skb, gfp_any());
1282
1283 timeo = sock_sndtimeo(ssk, nonblock);
1284 retry:
1285 sk = netlink_getsockbyportid(ssk, portid);
1286 if (IS_ERR(sk)) {
1287 kfree_skb(skb);
1288 return PTR_ERR(sk);
1289 }
1290 if (netlink_is_kernel(sk))
1291 return netlink_unicast_kernel(sk, skb, ssk);
1292
1293 if (sk_filter(sk, skb)) {
1294 err = skb->len;
1295 kfree_skb(skb);
1296 sock_put(sk);
1297 return err;
1298 }
1299
1300 err = netlink_attachskb(sk, skb, &timeo, ssk);
1301 if (err == 1)
1302 goto retry;
1303 if (err)
1304 return err;
1305
1306 return netlink_sendskb(sk, skb);
1307 }
1308 EXPORT_SYMBOL(netlink_unicast);
1309
1310 int netlink_has_listeners(struct sock *sk, unsigned int group)
1311 {
1312 int res = 0;
1313 struct listeners *listeners;
1314
1315 BUG_ON(!netlink_is_kernel(sk));
1316
1317 rcu_read_lock();
1318 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1319
1320 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1321 res = test_bit(group - 1, listeners->masks);
1322
1323 rcu_read_unlock();
1324
1325 return res;
1326 }
1327 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1328
1329 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1330 {
1331 struct netlink_sock *nlk = nlk_sk(sk);
1332
1333 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1334 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1335 netlink_skb_set_owner_r(skb, sk);
1336 __netlink_sendskb(sk, skb);
1337 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1338 }
1339 return -1;
1340 }
1341
1342 struct netlink_broadcast_data {
1343 struct sock *exclude_sk;
1344 struct net *net;
1345 u32 portid;
1346 u32 group;
1347 int failure;
1348 int delivery_failure;
1349 int congested;
1350 int delivered;
1351 gfp_t allocation;
1352 struct sk_buff *skb, *skb2;
1353 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1354 void *tx_data;
1355 };
1356
1357 static void do_one_broadcast(struct sock *sk,
1358 struct netlink_broadcast_data *p)
1359 {
1360 struct netlink_sock *nlk = nlk_sk(sk);
1361 int val;
1362
1363 if (p->exclude_sk == sk)
1364 return;
1365
1366 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1367 !test_bit(p->group - 1, nlk->groups))
1368 return;
1369
1370 if (!net_eq(sock_net(sk), p->net)) {
1371 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1372 return;
1373
1374 if (!peernet_has_id(sock_net(sk), p->net))
1375 return;
1376
1377 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1378 CAP_NET_BROADCAST))
1379 return;
1380 }
1381
1382 if (p->failure) {
1383 netlink_overrun(sk);
1384 return;
1385 }
1386
1387 sock_hold(sk);
1388 if (p->skb2 == NULL) {
1389 if (skb_shared(p->skb)) {
1390 p->skb2 = skb_clone(p->skb, p->allocation);
1391 } else {
1392 p->skb2 = skb_get(p->skb);
1393 /*
1394 * skb ownership may have been set when
1395 * delivered to a previous socket.
1396 */
1397 skb_orphan(p->skb2);
1398 }
1399 }
1400 if (p->skb2 == NULL) {
1401 netlink_overrun(sk);
1402 /* Clone failed. Notify ALL listeners. */
1403 p->failure = 1;
1404 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1405 p->delivery_failure = 1;
1406 goto out;
1407 }
1408 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1409 kfree_skb(p->skb2);
1410 p->skb2 = NULL;
1411 goto out;
1412 }
1413 if (sk_filter(sk, p->skb2)) {
1414 kfree_skb(p->skb2);
1415 p->skb2 = NULL;
1416 goto out;
1417 }
1418 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1419 if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
1420 NETLINK_CB(p->skb2).nsid_is_set = true;
1421 val = netlink_broadcast_deliver(sk, p->skb2);
1422 if (val < 0) {
1423 netlink_overrun(sk);
1424 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1425 p->delivery_failure = 1;
1426 } else {
1427 p->congested |= val;
1428 p->delivered = 1;
1429 p->skb2 = NULL;
1430 }
1431 out:
1432 sock_put(sk);
1433 }
1434
1435 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1436 u32 group, gfp_t allocation,
1437 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1438 void *filter_data)
1439 {
1440 struct net *net = sock_net(ssk);
1441 struct netlink_broadcast_data info;
1442 struct sock *sk;
1443
1444 skb = netlink_trim(skb, allocation);
1445
1446 info.exclude_sk = ssk;
1447 info.net = net;
1448 info.portid = portid;
1449 info.group = group;
1450 info.failure = 0;
1451 info.delivery_failure = 0;
1452 info.congested = 0;
1453 info.delivered = 0;
1454 info.allocation = allocation;
1455 info.skb = skb;
1456 info.skb2 = NULL;
1457 info.tx_filter = filter;
1458 info.tx_data = filter_data;
1459
1460 /* While we sleep in clone, do not allow to change socket list */
1461
1462 netlink_lock_table();
1463
1464 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1465 do_one_broadcast(sk, &info);
1466
1467 consume_skb(skb);
1468
1469 netlink_unlock_table();
1470
1471 if (info.delivery_failure) {
1472 kfree_skb(info.skb2);
1473 return -ENOBUFS;
1474 }
1475 consume_skb(info.skb2);
1476
1477 if (info.delivered) {
1478 if (info.congested && gfpflags_allow_blocking(allocation))
1479 yield();
1480 return 0;
1481 }
1482 return -ESRCH;
1483 }
1484 EXPORT_SYMBOL(netlink_broadcast_filtered);
1485
1486 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1487 u32 group, gfp_t allocation)
1488 {
1489 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1490 NULL, NULL);
1491 }
1492 EXPORT_SYMBOL(netlink_broadcast);
1493
1494 struct netlink_set_err_data {
1495 struct sock *exclude_sk;
1496 u32 portid;
1497 u32 group;
1498 int code;
1499 };
1500
1501 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1502 {
1503 struct netlink_sock *nlk = nlk_sk(sk);
1504 int ret = 0;
1505
1506 if (sk == p->exclude_sk)
1507 goto out;
1508
1509 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1510 goto out;
1511
1512 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1513 !test_bit(p->group - 1, nlk->groups))
1514 goto out;
1515
1516 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1517 ret = 1;
1518 goto out;
1519 }
1520
1521 sk->sk_err = p->code;
1522 sk->sk_error_report(sk);
1523 out:
1524 return ret;
1525 }
1526
1527 /**
1528 * netlink_set_err - report error to broadcast listeners
1529 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1530 * @portid: the PORTID of a process that we want to skip (if any)
1531 * @group: the broadcast group that will notice the error
1532 * @code: error code, must be negative (as usual in kernelspace)
1533 *
1534 * This function returns the number of broadcast listeners that have set the
1535 * NETLINK_NO_ENOBUFS socket option.
1536 */
1537 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1538 {
1539 struct netlink_set_err_data info;
1540 struct sock *sk;
1541 int ret = 0;
1542
1543 info.exclude_sk = ssk;
1544 info.portid = portid;
1545 info.group = group;
1546 /* sk->sk_err wants a positive error value */
1547 info.code = -code;
1548
1549 read_lock(&nl_table_lock);
1550
1551 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1552 ret += do_one_set_err(sk, &info);
1553
1554 read_unlock(&nl_table_lock);
1555 return ret;
1556 }
1557 EXPORT_SYMBOL(netlink_set_err);
1558
1559 /* must be called with netlink table grabbed */
1560 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1561 unsigned int group,
1562 int is_new)
1563 {
1564 int old, new = !!is_new, subscriptions;
1565
1566 old = test_bit(group - 1, nlk->groups);
1567 subscriptions = nlk->subscriptions - old + new;
1568 if (new)
1569 __set_bit(group - 1, nlk->groups);
1570 else
1571 __clear_bit(group - 1, nlk->groups);
1572 netlink_update_subscriptions(&nlk->sk, subscriptions);
1573 netlink_update_listeners(&nlk->sk);
1574 }
1575
1576 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1577 char __user *optval, unsigned int optlen)
1578 {
1579 struct sock *sk = sock->sk;
1580 struct netlink_sock *nlk = nlk_sk(sk);
1581 unsigned int val = 0;
1582 int err;
1583
1584 if (level != SOL_NETLINK)
1585 return -ENOPROTOOPT;
1586
1587 if (optlen >= sizeof(int) &&
1588 get_user(val, (unsigned int __user *)optval))
1589 return -EFAULT;
1590
1591 switch (optname) {
1592 case NETLINK_PKTINFO:
1593 if (val)
1594 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1595 else
1596 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1597 err = 0;
1598 break;
1599 case NETLINK_ADD_MEMBERSHIP:
1600 case NETLINK_DROP_MEMBERSHIP: {
1601 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1602 return -EPERM;
1603 err = netlink_realloc_groups(sk);
1604 if (err)
1605 return err;
1606 if (!val || val - 1 >= nlk->ngroups)
1607 return -EINVAL;
1608 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1609 err = nlk->netlink_bind(sock_net(sk), val);
1610 if (err)
1611 return err;
1612 }
1613 netlink_table_grab();
1614 netlink_update_socket_mc(nlk, val,
1615 optname == NETLINK_ADD_MEMBERSHIP);
1616 netlink_table_ungrab();
1617 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1618 nlk->netlink_unbind(sock_net(sk), val);
1619
1620 err = 0;
1621 break;
1622 }
1623 case NETLINK_BROADCAST_ERROR:
1624 if (val)
1625 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1626 else
1627 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1628 err = 0;
1629 break;
1630 case NETLINK_NO_ENOBUFS:
1631 if (val) {
1632 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1633 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1634 wake_up_interruptible(&nlk->wait);
1635 } else {
1636 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1637 }
1638 err = 0;
1639 break;
1640 case NETLINK_LISTEN_ALL_NSID:
1641 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1642 return -EPERM;
1643
1644 if (val)
1645 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1646 else
1647 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1648 err = 0;
1649 break;
1650 case NETLINK_CAP_ACK:
1651 if (val)
1652 nlk->flags |= NETLINK_F_CAP_ACK;
1653 else
1654 nlk->flags &= ~NETLINK_F_CAP_ACK;
1655 err = 0;
1656 break;
1657 case NETLINK_EXT_ACK:
1658 if (val)
1659 nlk->flags |= NETLINK_F_EXT_ACK;
1660 else
1661 nlk->flags &= ~NETLINK_F_EXT_ACK;
1662 err = 0;
1663 break;
1664 default:
1665 err = -ENOPROTOOPT;
1666 }
1667 return err;
1668 }
1669
1670 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1671 char __user *optval, int __user *optlen)
1672 {
1673 struct sock *sk = sock->sk;
1674 struct netlink_sock *nlk = nlk_sk(sk);
1675 int len, val, err;
1676
1677 if (level != SOL_NETLINK)
1678 return -ENOPROTOOPT;
1679
1680 if (get_user(len, optlen))
1681 return -EFAULT;
1682 if (len < 0)
1683 return -EINVAL;
1684
1685 switch (optname) {
1686 case NETLINK_PKTINFO:
1687 if (len < sizeof(int))
1688 return -EINVAL;
1689 len = sizeof(int);
1690 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1691 if (put_user(len, optlen) ||
1692 put_user(val, optval))
1693 return -EFAULT;
1694 err = 0;
1695 break;
1696 case NETLINK_BROADCAST_ERROR:
1697 if (len < sizeof(int))
1698 return -EINVAL;
1699 len = sizeof(int);
1700 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1701 if (put_user(len, optlen) ||
1702 put_user(val, optval))
1703 return -EFAULT;
1704 err = 0;
1705 break;
1706 case NETLINK_NO_ENOBUFS:
1707 if (len < sizeof(int))
1708 return -EINVAL;
1709 len = sizeof(int);
1710 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1711 if (put_user(len, optlen) ||
1712 put_user(val, optval))
1713 return -EFAULT;
1714 err = 0;
1715 break;
1716 case NETLINK_LIST_MEMBERSHIPS: {
1717 int pos, idx, shift;
1718
1719 err = 0;
1720 netlink_lock_table();
1721 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1722 if (len - pos < sizeof(u32))
1723 break;
1724
1725 idx = pos / sizeof(unsigned long);
1726 shift = (pos % sizeof(unsigned long)) * 8;
1727 if (put_user((u32)(nlk->groups[idx] >> shift),
1728 (u32 __user *)(optval + pos))) {
1729 err = -EFAULT;
1730 break;
1731 }
1732 }
1733 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1734 err = -EFAULT;
1735 netlink_unlock_table();
1736 break;
1737 }
1738 case NETLINK_CAP_ACK:
1739 if (len < sizeof(int))
1740 return -EINVAL;
1741 len = sizeof(int);
1742 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1743 if (put_user(len, optlen) ||
1744 put_user(val, optval))
1745 return -EFAULT;
1746 err = 0;
1747 break;
1748 case NETLINK_EXT_ACK:
1749 if (len < sizeof(int))
1750 return -EINVAL;
1751 len = sizeof(int);
1752 val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0;
1753 if (put_user(len, optlen) || put_user(val, optval))
1754 return -EFAULT;
1755 err = 0;
1756 break;
1757 default:
1758 err = -ENOPROTOOPT;
1759 }
1760 return err;
1761 }
1762
1763 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1764 {
1765 struct nl_pktinfo info;
1766
1767 info.group = NETLINK_CB(skb).dst_group;
1768 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1769 }
1770
1771 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1772 struct sk_buff *skb)
1773 {
1774 if (!NETLINK_CB(skb).nsid_is_set)
1775 return;
1776
1777 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1778 &NETLINK_CB(skb).nsid);
1779 }
1780
1781 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1782 {
1783 struct sock *sk = sock->sk;
1784 struct netlink_sock *nlk = nlk_sk(sk);
1785 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1786 u32 dst_portid;
1787 u32 dst_group;
1788 struct sk_buff *skb;
1789 int err;
1790 struct scm_cookie scm;
1791 u32 netlink_skb_flags = 0;
1792
1793 if (msg->msg_flags&MSG_OOB)
1794 return -EOPNOTSUPP;
1795
1796 err = scm_send(sock, msg, &scm, true);
1797 if (err < 0)
1798 return err;
1799
1800 if (msg->msg_namelen) {
1801 err = -EINVAL;
1802 if (addr->nl_family != AF_NETLINK)
1803 goto out;
1804 dst_portid = addr->nl_pid;
1805 dst_group = ffs(addr->nl_groups);
1806 err = -EPERM;
1807 if ((dst_group || dst_portid) &&
1808 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1809 goto out;
1810 netlink_skb_flags |= NETLINK_SKB_DST;
1811 } else {
1812 dst_portid = nlk->dst_portid;
1813 dst_group = nlk->dst_group;
1814 }
1815
1816 if (!nlk->bound) {
1817 err = netlink_autobind(sock);
1818 if (err)
1819 goto out;
1820 } else {
1821 /* Ensure nlk is hashed and visible. */
1822 smp_rmb();
1823 }
1824
1825 err = -EMSGSIZE;
1826 if (len > sk->sk_sndbuf - 32)
1827 goto out;
1828 err = -ENOBUFS;
1829 skb = netlink_alloc_large_skb(len, dst_group);
1830 if (skb == NULL)
1831 goto out;
1832
1833 NETLINK_CB(skb).portid = nlk->portid;
1834 NETLINK_CB(skb).dst_group = dst_group;
1835 NETLINK_CB(skb).creds = scm.creds;
1836 NETLINK_CB(skb).flags = netlink_skb_flags;
1837
1838 err = -EFAULT;
1839 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1840 kfree_skb(skb);
1841 goto out;
1842 }
1843
1844 err = security_netlink_send(sk, skb);
1845 if (err) {
1846 kfree_skb(skb);
1847 goto out;
1848 }
1849
1850 if (dst_group) {
1851 refcount_inc(&skb->users);
1852 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1853 }
1854 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1855
1856 out:
1857 scm_destroy(&scm);
1858 return err;
1859 }
1860
1861 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1862 int flags)
1863 {
1864 struct scm_cookie scm;
1865 struct sock *sk = sock->sk;
1866 struct netlink_sock *nlk = nlk_sk(sk);
1867 int noblock = flags&MSG_DONTWAIT;
1868 size_t copied;
1869 struct sk_buff *skb, *data_skb;
1870 int err, ret;
1871
1872 if (flags&MSG_OOB)
1873 return -EOPNOTSUPP;
1874
1875 copied = 0;
1876
1877 skb = skb_recv_datagram(sk, flags, noblock, &err);
1878 if (skb == NULL)
1879 goto out;
1880
1881 data_skb = skb;
1882
1883 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1884 if (unlikely(skb_shinfo(skb)->frag_list)) {
1885 /*
1886 * If this skb has a frag_list, then here that means that we
1887 * will have to use the frag_list skb's data for compat tasks
1888 * and the regular skb's data for normal (non-compat) tasks.
1889 *
1890 * If we need to send the compat skb, assign it to the
1891 * 'data_skb' variable so that it will be used below for data
1892 * copying. We keep 'skb' for everything else, including
1893 * freeing both later.
1894 */
1895 if (flags & MSG_CMSG_COMPAT)
1896 data_skb = skb_shinfo(skb)->frag_list;
1897 }
1898 #endif
1899
1900 /* Record the max length of recvmsg() calls for future allocations */
1901 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1902 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1903 SKB_WITH_OVERHEAD(32768));
1904
1905 copied = data_skb->len;
1906 if (len < copied) {
1907 msg->msg_flags |= MSG_TRUNC;
1908 copied = len;
1909 }
1910
1911 skb_reset_transport_header(data_skb);
1912 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1913
1914 if (msg->msg_name) {
1915 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1916 addr->nl_family = AF_NETLINK;
1917 addr->nl_pad = 0;
1918 addr->nl_pid = NETLINK_CB(skb).portid;
1919 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1920 msg->msg_namelen = sizeof(*addr);
1921 }
1922
1923 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1924 netlink_cmsg_recv_pktinfo(msg, skb);
1925 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1926 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1927
1928 memset(&scm, 0, sizeof(scm));
1929 scm.creds = *NETLINK_CREDS(skb);
1930 if (flags & MSG_TRUNC)
1931 copied = data_skb->len;
1932
1933 skb_free_datagram(sk, skb);
1934
1935 if (nlk->cb_running &&
1936 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1937 ret = netlink_dump(sk);
1938 if (ret) {
1939 sk->sk_err = -ret;
1940 sk->sk_error_report(sk);
1941 }
1942 }
1943
1944 scm_recv(sock, msg, &scm, flags);
1945 out:
1946 netlink_rcv_wake(sk);
1947 return err ? : copied;
1948 }
1949
1950 static void netlink_data_ready(struct sock *sk)
1951 {
1952 BUG();
1953 }
1954
1955 /*
1956 * We export these functions to other modules. They provide a
1957 * complete set of kernel non-blocking support for message
1958 * queueing.
1959 */
1960
1961 struct sock *
1962 __netlink_kernel_create(struct net *net, int unit, struct module *module,
1963 struct netlink_kernel_cfg *cfg)
1964 {
1965 struct socket *sock;
1966 struct sock *sk;
1967 struct netlink_sock *nlk;
1968 struct listeners *listeners = NULL;
1969 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
1970 unsigned int groups;
1971
1972 BUG_ON(!nl_table);
1973
1974 if (unit < 0 || unit >= MAX_LINKS)
1975 return NULL;
1976
1977 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1978 return NULL;
1979
1980 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
1981 goto out_sock_release_nosk;
1982
1983 sk = sock->sk;
1984
1985 if (!cfg || cfg->groups < 32)
1986 groups = 32;
1987 else
1988 groups = cfg->groups;
1989
1990 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1991 if (!listeners)
1992 goto out_sock_release;
1993
1994 sk->sk_data_ready = netlink_data_ready;
1995 if (cfg && cfg->input)
1996 nlk_sk(sk)->netlink_rcv = cfg->input;
1997
1998 if (netlink_insert(sk, 0))
1999 goto out_sock_release;
2000
2001 nlk = nlk_sk(sk);
2002 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
2003
2004 netlink_table_grab();
2005 if (!nl_table[unit].registered) {
2006 nl_table[unit].groups = groups;
2007 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2008 nl_table[unit].cb_mutex = cb_mutex;
2009 nl_table[unit].module = module;
2010 if (cfg) {
2011 nl_table[unit].bind = cfg->bind;
2012 nl_table[unit].unbind = cfg->unbind;
2013 nl_table[unit].flags = cfg->flags;
2014 if (cfg->compare)
2015 nl_table[unit].compare = cfg->compare;
2016 }
2017 nl_table[unit].registered = 1;
2018 } else {
2019 kfree(listeners);
2020 nl_table[unit].registered++;
2021 }
2022 netlink_table_ungrab();
2023 return sk;
2024
2025 out_sock_release:
2026 kfree(listeners);
2027 netlink_kernel_release(sk);
2028 return NULL;
2029
2030 out_sock_release_nosk:
2031 sock_release(sock);
2032 return NULL;
2033 }
2034 EXPORT_SYMBOL(__netlink_kernel_create);
2035
2036 void
2037 netlink_kernel_release(struct sock *sk)
2038 {
2039 if (sk == NULL || sk->sk_socket == NULL)
2040 return;
2041
2042 sock_release(sk->sk_socket);
2043 }
2044 EXPORT_SYMBOL(netlink_kernel_release);
2045
2046 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2047 {
2048 struct listeners *new, *old;
2049 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2050
2051 if (groups < 32)
2052 groups = 32;
2053
2054 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2055 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2056 if (!new)
2057 return -ENOMEM;
2058 old = nl_deref_protected(tbl->listeners);
2059 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2060 rcu_assign_pointer(tbl->listeners, new);
2061
2062 kfree_rcu(old, rcu);
2063 }
2064 tbl->groups = groups;
2065
2066 return 0;
2067 }
2068
2069 /**
2070 * netlink_change_ngroups - change number of multicast groups
2071 *
2072 * This changes the number of multicast groups that are available
2073 * on a certain netlink family. Note that it is not possible to
2074 * change the number of groups to below 32. Also note that it does
2075 * not implicitly call netlink_clear_multicast_users() when the
2076 * number of groups is reduced.
2077 *
2078 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2079 * @groups: The new number of groups.
2080 */
2081 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2082 {
2083 int err;
2084
2085 netlink_table_grab();
2086 err = __netlink_change_ngroups(sk, groups);
2087 netlink_table_ungrab();
2088
2089 return err;
2090 }
2091
2092 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2093 {
2094 struct sock *sk;
2095 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2096
2097 sk_for_each_bound(sk, &tbl->mc_list)
2098 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2099 }
2100
2101 struct nlmsghdr *
2102 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2103 {
2104 struct nlmsghdr *nlh;
2105 int size = nlmsg_msg_size(len);
2106
2107 nlh = skb_put(skb, NLMSG_ALIGN(size));
2108 nlh->nlmsg_type = type;
2109 nlh->nlmsg_len = size;
2110 nlh->nlmsg_flags = flags;
2111 nlh->nlmsg_pid = portid;
2112 nlh->nlmsg_seq = seq;
2113 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2114 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2115 return nlh;
2116 }
2117 EXPORT_SYMBOL(__nlmsg_put);
2118
2119 /*
2120 * It looks a bit ugly.
2121 * It would be better to create kernel thread.
2122 */
2123
2124 static int netlink_dump(struct sock *sk)
2125 {
2126 struct netlink_sock *nlk = nlk_sk(sk);
2127 struct netlink_callback *cb;
2128 struct sk_buff *skb = NULL;
2129 struct nlmsghdr *nlh;
2130 struct module *module;
2131 int len, err = -ENOBUFS;
2132 int alloc_min_size;
2133 int alloc_size;
2134
2135 mutex_lock(nlk->cb_mutex);
2136 if (!nlk->cb_running) {
2137 err = -EINVAL;
2138 goto errout_skb;
2139 }
2140
2141 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2142 goto errout_skb;
2143
2144 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2145 * required, but it makes sense to _attempt_ a 16K bytes allocation
2146 * to reduce number of system calls on dump operations, if user
2147 * ever provided a big enough buffer.
2148 */
2149 cb = &nlk->cb;
2150 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2151
2152 if (alloc_min_size < nlk->max_recvmsg_len) {
2153 alloc_size = nlk->max_recvmsg_len;
2154 skb = alloc_skb(alloc_size,
2155 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2156 __GFP_NOWARN | __GFP_NORETRY);
2157 }
2158 if (!skb) {
2159 alloc_size = alloc_min_size;
2160 skb = alloc_skb(alloc_size, GFP_KERNEL);
2161 }
2162 if (!skb)
2163 goto errout_skb;
2164
2165 /* Trim skb to allocated size. User is expected to provide buffer as
2166 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2167 * netlink_recvmsg())). dump will pack as many smaller messages as
2168 * could fit within the allocated skb. skb is typically allocated
2169 * with larger space than required (could be as much as near 2x the
2170 * requested size with align to next power of 2 approach). Allowing
2171 * dump to use the excess space makes it difficult for a user to have a
2172 * reasonable static buffer based on the expected largest dump of a
2173 * single netdev. The outcome is MSG_TRUNC error.
2174 */
2175 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2176 netlink_skb_set_owner_r(skb, sk);
2177
2178 len = cb->dump(skb, cb);
2179
2180 if (len > 0) {
2181 mutex_unlock(nlk->cb_mutex);
2182
2183 if (sk_filter(sk, skb))
2184 kfree_skb(skb);
2185 else
2186 __netlink_sendskb(sk, skb);
2187 return 0;
2188 }
2189
2190 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2191 if (!nlh)
2192 goto errout_skb;
2193
2194 nl_dump_check_consistent(cb, nlh);
2195
2196 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2197
2198 if (sk_filter(sk, skb))
2199 kfree_skb(skb);
2200 else
2201 __netlink_sendskb(sk, skb);
2202
2203 if (cb->done)
2204 cb->done(cb);
2205
2206 nlk->cb_running = false;
2207 module = cb->module;
2208 skb = cb->skb;
2209 mutex_unlock(nlk->cb_mutex);
2210 module_put(module);
2211 consume_skb(skb);
2212 return 0;
2213
2214 errout_skb:
2215 mutex_unlock(nlk->cb_mutex);
2216 kfree_skb(skb);
2217 return err;
2218 }
2219
2220 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2221 const struct nlmsghdr *nlh,
2222 struct netlink_dump_control *control)
2223 {
2224 struct netlink_callback *cb;
2225 struct sock *sk;
2226 struct netlink_sock *nlk;
2227 int ret;
2228
2229 refcount_inc(&skb->users);
2230
2231 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2232 if (sk == NULL) {
2233 ret = -ECONNREFUSED;
2234 goto error_free;
2235 }
2236
2237 nlk = nlk_sk(sk);
2238 mutex_lock(nlk->cb_mutex);
2239 /* A dump is in progress... */
2240 if (nlk->cb_running) {
2241 ret = -EBUSY;
2242 goto error_unlock;
2243 }
2244 /* add reference of module which cb->dump belongs to */
2245 if (!try_module_get(control->module)) {
2246 ret = -EPROTONOSUPPORT;
2247 goto error_unlock;
2248 }
2249
2250 cb = &nlk->cb;
2251 memset(cb, 0, sizeof(*cb));
2252 cb->start = control->start;
2253 cb->dump = control->dump;
2254 cb->done = control->done;
2255 cb->nlh = nlh;
2256 cb->data = control->data;
2257 cb->module = control->module;
2258 cb->min_dump_alloc = control->min_dump_alloc;
2259 cb->skb = skb;
2260
2261 nlk->cb_running = true;
2262
2263 mutex_unlock(nlk->cb_mutex);
2264
2265 if (cb->start)
2266 cb->start(cb);
2267
2268 ret = netlink_dump(sk);
2269 sock_put(sk);
2270
2271 if (ret)
2272 return ret;
2273
2274 /* We successfully started a dump, by returning -EINTR we
2275 * signal not to send ACK even if it was requested.
2276 */
2277 return -EINTR;
2278
2279 error_unlock:
2280 sock_put(sk);
2281 mutex_unlock(nlk->cb_mutex);
2282 error_free:
2283 kfree_skb(skb);
2284 return ret;
2285 }
2286 EXPORT_SYMBOL(__netlink_dump_start);
2287
2288 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
2289 const struct netlink_ext_ack *extack)
2290 {
2291 struct sk_buff *skb;
2292 struct nlmsghdr *rep;
2293 struct nlmsgerr *errmsg;
2294 size_t payload = sizeof(*errmsg);
2295 size_t tlvlen = 0;
2296 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2297 unsigned int flags = 0;
2298
2299 /* Error messages get the original request appened, unless the user
2300 * requests to cap the error message, and get extra error data if
2301 * requested.
2302 */
2303 if (err) {
2304 if (!(nlk->flags & NETLINK_F_CAP_ACK))
2305 payload += nlmsg_len(nlh);
2306 else
2307 flags |= NLM_F_CAPPED;
2308 if (nlk->flags & NETLINK_F_EXT_ACK && extack) {
2309 if (extack->_msg)
2310 tlvlen += nla_total_size(strlen(extack->_msg) + 1);
2311 if (extack->bad_attr)
2312 tlvlen += nla_total_size(sizeof(u32));
2313 }
2314 } else {
2315 flags |= NLM_F_CAPPED;
2316
2317 if (nlk->flags & NETLINK_F_EXT_ACK &&
2318 extack && extack->cookie_len)
2319 tlvlen += nla_total_size(extack->cookie_len);
2320 }
2321
2322 if (tlvlen)
2323 flags |= NLM_F_ACK_TLVS;
2324
2325 skb = nlmsg_new(payload + tlvlen, GFP_KERNEL);
2326 if (!skb) {
2327 struct sock *sk;
2328
2329 sk = netlink_lookup(sock_net(in_skb->sk),
2330 in_skb->sk->sk_protocol,
2331 NETLINK_CB(in_skb).portid);
2332 if (sk) {
2333 sk->sk_err = ENOBUFS;
2334 sk->sk_error_report(sk);
2335 sock_put(sk);
2336 }
2337 return;
2338 }
2339
2340 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2341 NLMSG_ERROR, payload, flags);
2342 errmsg = nlmsg_data(rep);
2343 errmsg->error = err;
2344 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2345
2346 if (nlk->flags & NETLINK_F_EXT_ACK && extack) {
2347 if (err) {
2348 if (extack->_msg)
2349 WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG,
2350 extack->_msg));
2351 if (extack->bad_attr &&
2352 !WARN_ON((u8 *)extack->bad_attr < in_skb->data ||
2353 (u8 *)extack->bad_attr >= in_skb->data +
2354 in_skb->len))
2355 WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
2356 (u8 *)extack->bad_attr -
2357 in_skb->data));
2358 } else {
2359 if (extack->cookie_len)
2360 WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
2361 extack->cookie_len,
2362 extack->cookie));
2363 }
2364 }
2365
2366 nlmsg_end(skb, rep);
2367
2368 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2369 }
2370 EXPORT_SYMBOL(netlink_ack);
2371
2372 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2373 struct nlmsghdr *,
2374 struct netlink_ext_ack *))
2375 {
2376 struct netlink_ext_ack extack = {};
2377 struct nlmsghdr *nlh;
2378 int err;
2379
2380 while (skb->len >= nlmsg_total_size(0)) {
2381 int msglen;
2382
2383 nlh = nlmsg_hdr(skb);
2384 err = 0;
2385
2386 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2387 return 0;
2388
2389 /* Only requests are handled by the kernel */
2390 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2391 goto ack;
2392
2393 /* Skip control messages */
2394 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2395 goto ack;
2396
2397 err = cb(skb, nlh, &extack);
2398 if (err == -EINTR)
2399 goto skip;
2400
2401 ack:
2402 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2403 netlink_ack(skb, nlh, err, &extack);
2404
2405 skip:
2406 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2407 if (msglen > skb->len)
2408 msglen = skb->len;
2409 skb_pull(skb, msglen);
2410 }
2411
2412 return 0;
2413 }
2414 EXPORT_SYMBOL(netlink_rcv_skb);
2415
2416 /**
2417 * nlmsg_notify - send a notification netlink message
2418 * @sk: netlink socket to use
2419 * @skb: notification message
2420 * @portid: destination netlink portid for reports or 0
2421 * @group: destination multicast group or 0
2422 * @report: 1 to report back, 0 to disable
2423 * @flags: allocation flags
2424 */
2425 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2426 unsigned int group, int report, gfp_t flags)
2427 {
2428 int err = 0;
2429
2430 if (group) {
2431 int exclude_portid = 0;
2432
2433 if (report) {
2434 refcount_inc(&skb->users);
2435 exclude_portid = portid;
2436 }
2437
2438 /* errors reported via destination sk->sk_err, but propagate
2439 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2440 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2441 }
2442
2443 if (report) {
2444 int err2;
2445
2446 err2 = nlmsg_unicast(sk, skb, portid);
2447 if (!err || err == -ESRCH)
2448 err = err2;
2449 }
2450
2451 return err;
2452 }
2453 EXPORT_SYMBOL(nlmsg_notify);
2454
2455 #ifdef CONFIG_PROC_FS
2456 struct nl_seq_iter {
2457 struct seq_net_private p;
2458 struct rhashtable_iter hti;
2459 int link;
2460 };
2461
2462 static int netlink_walk_start(struct nl_seq_iter *iter)
2463 {
2464 int err;
2465
2466 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti,
2467 GFP_KERNEL);
2468 if (err) {
2469 iter->link = MAX_LINKS;
2470 return err;
2471 }
2472
2473 err = rhashtable_walk_start(&iter->hti);
2474 return err == -EAGAIN ? 0 : err;
2475 }
2476
2477 static void netlink_walk_stop(struct nl_seq_iter *iter)
2478 {
2479 rhashtable_walk_stop(&iter->hti);
2480 rhashtable_walk_exit(&iter->hti);
2481 }
2482
2483 static void *__netlink_seq_next(struct seq_file *seq)
2484 {
2485 struct nl_seq_iter *iter = seq->private;
2486 struct netlink_sock *nlk;
2487
2488 do {
2489 for (;;) {
2490 int err;
2491
2492 nlk = rhashtable_walk_next(&iter->hti);
2493
2494 if (IS_ERR(nlk)) {
2495 if (PTR_ERR(nlk) == -EAGAIN)
2496 continue;
2497
2498 return nlk;
2499 }
2500
2501 if (nlk)
2502 break;
2503
2504 netlink_walk_stop(iter);
2505 if (++iter->link >= MAX_LINKS)
2506 return NULL;
2507
2508 err = netlink_walk_start(iter);
2509 if (err)
2510 return ERR_PTR(err);
2511 }
2512 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2513
2514 return nlk;
2515 }
2516
2517 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2518 {
2519 struct nl_seq_iter *iter = seq->private;
2520 void *obj = SEQ_START_TOKEN;
2521 loff_t pos;
2522 int err;
2523
2524 iter->link = 0;
2525
2526 err = netlink_walk_start(iter);
2527 if (err)
2528 return ERR_PTR(err);
2529
2530 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2531 obj = __netlink_seq_next(seq);
2532
2533 return obj;
2534 }
2535
2536 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2537 {
2538 ++*pos;
2539 return __netlink_seq_next(seq);
2540 }
2541
2542 static void netlink_seq_stop(struct seq_file *seq, void *v)
2543 {
2544 struct nl_seq_iter *iter = seq->private;
2545
2546 if (iter->link >= MAX_LINKS)
2547 return;
2548
2549 netlink_walk_stop(iter);
2550 }
2551
2552
2553 static int netlink_seq_show(struct seq_file *seq, void *v)
2554 {
2555 if (v == SEQ_START_TOKEN) {
2556 seq_puts(seq,
2557 "sk Eth Pid Groups "
2558 "Rmem Wmem Dump Locks Drops Inode\n");
2559 } else {
2560 struct sock *s = v;
2561 struct netlink_sock *nlk = nlk_sk(s);
2562
2563 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2564 s,
2565 s->sk_protocol,
2566 nlk->portid,
2567 nlk->groups ? (u32)nlk->groups[0] : 0,
2568 sk_rmem_alloc_get(s),
2569 sk_wmem_alloc_get(s),
2570 nlk->cb_running,
2571 refcount_read(&s->sk_refcnt),
2572 atomic_read(&s->sk_drops),
2573 sock_i_ino(s)
2574 );
2575
2576 }
2577 return 0;
2578 }
2579
2580 static const struct seq_operations netlink_seq_ops = {
2581 .start = netlink_seq_start,
2582 .next = netlink_seq_next,
2583 .stop = netlink_seq_stop,
2584 .show = netlink_seq_show,
2585 };
2586
2587
2588 static int netlink_seq_open(struct inode *inode, struct file *file)
2589 {
2590 return seq_open_net(inode, file, &netlink_seq_ops,
2591 sizeof(struct nl_seq_iter));
2592 }
2593
2594 static const struct file_operations netlink_seq_fops = {
2595 .owner = THIS_MODULE,
2596 .open = netlink_seq_open,
2597 .read = seq_read,
2598 .llseek = seq_lseek,
2599 .release = seq_release_net,
2600 };
2601
2602 #endif
2603
2604 int netlink_register_notifier(struct notifier_block *nb)
2605 {
2606 return blocking_notifier_chain_register(&netlink_chain, nb);
2607 }
2608 EXPORT_SYMBOL(netlink_register_notifier);
2609
2610 int netlink_unregister_notifier(struct notifier_block *nb)
2611 {
2612 return blocking_notifier_chain_unregister(&netlink_chain, nb);
2613 }
2614 EXPORT_SYMBOL(netlink_unregister_notifier);
2615
2616 static const struct proto_ops netlink_ops = {
2617 .family = PF_NETLINK,
2618 .owner = THIS_MODULE,
2619 .release = netlink_release,
2620 .bind = netlink_bind,
2621 .connect = netlink_connect,
2622 .socketpair = sock_no_socketpair,
2623 .accept = sock_no_accept,
2624 .getname = netlink_getname,
2625 .poll = datagram_poll,
2626 .ioctl = netlink_ioctl,
2627 .listen = sock_no_listen,
2628 .shutdown = sock_no_shutdown,
2629 .setsockopt = netlink_setsockopt,
2630 .getsockopt = netlink_getsockopt,
2631 .sendmsg = netlink_sendmsg,
2632 .recvmsg = netlink_recvmsg,
2633 .mmap = sock_no_mmap,
2634 .sendpage = sock_no_sendpage,
2635 };
2636
2637 static const struct net_proto_family netlink_family_ops = {
2638 .family = PF_NETLINK,
2639 .create = netlink_create,
2640 .owner = THIS_MODULE, /* for consistency 8) */
2641 };
2642
2643 static int __net_init netlink_net_init(struct net *net)
2644 {
2645 #ifdef CONFIG_PROC_FS
2646 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
2647 return -ENOMEM;
2648 #endif
2649 return 0;
2650 }
2651
2652 static void __net_exit netlink_net_exit(struct net *net)
2653 {
2654 #ifdef CONFIG_PROC_FS
2655 remove_proc_entry("netlink", net->proc_net);
2656 #endif
2657 }
2658
2659 static void __init netlink_add_usersock_entry(void)
2660 {
2661 struct listeners *listeners;
2662 int groups = 32;
2663
2664 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2665 if (!listeners)
2666 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2667
2668 netlink_table_grab();
2669
2670 nl_table[NETLINK_USERSOCK].groups = groups;
2671 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2672 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2673 nl_table[NETLINK_USERSOCK].registered = 1;
2674 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2675
2676 netlink_table_ungrab();
2677 }
2678
2679 static struct pernet_operations __net_initdata netlink_net_ops = {
2680 .init = netlink_net_init,
2681 .exit = netlink_net_exit,
2682 };
2683
2684 static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2685 {
2686 const struct netlink_sock *nlk = data;
2687 struct netlink_compare_arg arg;
2688
2689 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2690 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2691 }
2692
2693 static const struct rhashtable_params netlink_rhashtable_params = {
2694 .head_offset = offsetof(struct netlink_sock, node),
2695 .key_len = netlink_compare_arg_len,
2696 .obj_hashfn = netlink_hash,
2697 .obj_cmpfn = netlink_compare,
2698 .automatic_shrinking = true,
2699 };
2700
2701 static int __init netlink_proto_init(void)
2702 {
2703 int i;
2704 int err = proto_register(&netlink_proto, 0);
2705
2706 if (err != 0)
2707 goto out;
2708
2709 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2710
2711 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2712 if (!nl_table)
2713 goto panic;
2714
2715 for (i = 0; i < MAX_LINKS; i++) {
2716 if (rhashtable_init(&nl_table[i].hash,
2717 &netlink_rhashtable_params) < 0) {
2718 while (--i > 0)
2719 rhashtable_destroy(&nl_table[i].hash);
2720 kfree(nl_table);
2721 goto panic;
2722 }
2723 }
2724
2725 INIT_LIST_HEAD(&netlink_tap_all);
2726
2727 netlink_add_usersock_entry();
2728
2729 sock_register(&netlink_family_ops);
2730 register_pernet_subsys(&netlink_net_ops);
2731 /* The netlink device handler may be needed early. */
2732 rtnetlink_init();
2733 out:
2734 return err;
2735 panic:
2736 panic("netlink_init: Cannot allocate nl_table\n");
2737 }
2738
2739 core_initcall(netlink_proto_init);
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