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