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