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Merge branch 'parisc-4.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/deller...
[deliverable/linux.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 ATOMIC_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
333 module_put(nlk->cb.module);
334 kfree_skb(nlk->cb.skb);
335 }
336
337 skb_queue_purge(&sk->sk_receive_queue);
338
339 if (!sock_flag(sk, SOCK_DEAD)) {
340 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
341 return;
342 }
343
344 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
345 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
346 WARN_ON(nlk_sk(sk)->groups);
347 }
348
349 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
350 * SMP. Look, when several writers sleep and reader wakes them up, all but one
351 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
352 * this, _but_ remember, it adds useless work on UP machines.
353 */
354
355 void netlink_table_grab(void)
356 __acquires(nl_table_lock)
357 {
358 might_sleep();
359
360 write_lock_irq(&nl_table_lock);
361
362 if (atomic_read(&nl_table_users)) {
363 DECLARE_WAITQUEUE(wait, current);
364
365 add_wait_queue_exclusive(&nl_table_wait, &wait);
366 for (;;) {
367 set_current_state(TASK_UNINTERRUPTIBLE);
368 if (atomic_read(&nl_table_users) == 0)
369 break;
370 write_unlock_irq(&nl_table_lock);
371 schedule();
372 write_lock_irq(&nl_table_lock);
373 }
374
375 __set_current_state(TASK_RUNNING);
376 remove_wait_queue(&nl_table_wait, &wait);
377 }
378 }
379
380 void netlink_table_ungrab(void)
381 __releases(nl_table_lock)
382 {
383 write_unlock_irq(&nl_table_lock);
384 wake_up(&nl_table_wait);
385 }
386
387 static inline void
388 netlink_lock_table(void)
389 {
390 /* read_lock() synchronizes us to netlink_table_grab */
391
392 read_lock(&nl_table_lock);
393 atomic_inc(&nl_table_users);
394 read_unlock(&nl_table_lock);
395 }
396
397 static inline void
398 netlink_unlock_table(void)
399 {
400 if (atomic_dec_and_test(&nl_table_users))
401 wake_up(&nl_table_wait);
402 }
403
404 struct netlink_compare_arg
405 {
406 possible_net_t pnet;
407 u32 portid;
408 };
409
410 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
411 #define netlink_compare_arg_len \
412 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
413
414 static inline int netlink_compare(struct rhashtable_compare_arg *arg,
415 const void *ptr)
416 {
417 const struct netlink_compare_arg *x = arg->key;
418 const struct netlink_sock *nlk = ptr;
419
420 return nlk->portid != x->portid ||
421 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
422 }
423
424 static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
425 struct net *net, u32 portid)
426 {
427 memset(arg, 0, sizeof(*arg));
428 write_pnet(&arg->pnet, net);
429 arg->portid = portid;
430 }
431
432 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
433 struct net *net)
434 {
435 struct netlink_compare_arg arg;
436
437 netlink_compare_arg_init(&arg, net, portid);
438 return rhashtable_lookup_fast(&table->hash, &arg,
439 netlink_rhashtable_params);
440 }
441
442 static int __netlink_insert(struct netlink_table *table, struct sock *sk)
443 {
444 struct netlink_compare_arg arg;
445
446 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
447 return rhashtable_lookup_insert_key(&table->hash, &arg,
448 &nlk_sk(sk)->node,
449 netlink_rhashtable_params);
450 }
451
452 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
453 {
454 struct netlink_table *table = &nl_table[protocol];
455 struct sock *sk;
456
457 rcu_read_lock();
458 sk = __netlink_lookup(table, portid, net);
459 if (sk)
460 sock_hold(sk);
461 rcu_read_unlock();
462
463 return sk;
464 }
465
466 static const struct proto_ops netlink_ops;
467
468 static void
469 netlink_update_listeners(struct sock *sk)
470 {
471 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
472 unsigned long mask;
473 unsigned int i;
474 struct listeners *listeners;
475
476 listeners = nl_deref_protected(tbl->listeners);
477 if (!listeners)
478 return;
479
480 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
481 mask = 0;
482 sk_for_each_bound(sk, &tbl->mc_list) {
483 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
484 mask |= nlk_sk(sk)->groups[i];
485 }
486 listeners->masks[i] = mask;
487 }
488 /* this function is only called with the netlink table "grabbed", which
489 * makes sure updates are visible before bind or setsockopt return. */
490 }
491
492 static int netlink_insert(struct sock *sk, u32 portid)
493 {
494 struct netlink_table *table = &nl_table[sk->sk_protocol];
495 int err;
496
497 lock_sock(sk);
498
499 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
500 if (nlk_sk(sk)->bound)
501 goto err;
502
503 err = -ENOMEM;
504 if (BITS_PER_LONG > 32 &&
505 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
506 goto err;
507
508 nlk_sk(sk)->portid = portid;
509 sock_hold(sk);
510
511 err = __netlink_insert(table, sk);
512 if (err) {
513 /* In case the hashtable backend returns with -EBUSY
514 * from here, it must not escape to the caller.
515 */
516 if (unlikely(err == -EBUSY))
517 err = -EOVERFLOW;
518 if (err == -EEXIST)
519 err = -EADDRINUSE;
520 sock_put(sk);
521 goto err;
522 }
523
524 /* We need to ensure that the socket is hashed and visible. */
525 smp_wmb();
526 nlk_sk(sk)->bound = portid;
527
528 err:
529 release_sock(sk);
530 return err;
531 }
532
533 static void netlink_remove(struct sock *sk)
534 {
535 struct netlink_table *table;
536
537 table = &nl_table[sk->sk_protocol];
538 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
539 netlink_rhashtable_params)) {
540 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
541 __sock_put(sk);
542 }
543
544 netlink_table_grab();
545 if (nlk_sk(sk)->subscriptions) {
546 __sk_del_bind_node(sk);
547 netlink_update_listeners(sk);
548 }
549 if (sk->sk_protocol == NETLINK_GENERIC)
550 atomic_inc(&genl_sk_destructing_cnt);
551 netlink_table_ungrab();
552 }
553
554 static struct proto netlink_proto = {
555 .name = "NETLINK",
556 .owner = THIS_MODULE,
557 .obj_size = sizeof(struct netlink_sock),
558 };
559
560 static int __netlink_create(struct net *net, struct socket *sock,
561 struct mutex *cb_mutex, int protocol,
562 int kern)
563 {
564 struct sock *sk;
565 struct netlink_sock *nlk;
566
567 sock->ops = &netlink_ops;
568
569 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
570 if (!sk)
571 return -ENOMEM;
572
573 sock_init_data(sock, sk);
574
575 nlk = nlk_sk(sk);
576 if (cb_mutex) {
577 nlk->cb_mutex = cb_mutex;
578 } else {
579 nlk->cb_mutex = &nlk->cb_def_mutex;
580 mutex_init(nlk->cb_mutex);
581 }
582 init_waitqueue_head(&nlk->wait);
583
584 sk->sk_destruct = netlink_sock_destruct;
585 sk->sk_protocol = protocol;
586 return 0;
587 }
588
589 static int netlink_create(struct net *net, struct socket *sock, int protocol,
590 int kern)
591 {
592 struct module *module = NULL;
593 struct mutex *cb_mutex;
594 struct netlink_sock *nlk;
595 int (*bind)(struct net *net, int group);
596 void (*unbind)(struct net *net, int group);
597 int err = 0;
598
599 sock->state = SS_UNCONNECTED;
600
601 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
602 return -ESOCKTNOSUPPORT;
603
604 if (protocol < 0 || protocol >= MAX_LINKS)
605 return -EPROTONOSUPPORT;
606
607 netlink_lock_table();
608 #ifdef CONFIG_MODULES
609 if (!nl_table[protocol].registered) {
610 netlink_unlock_table();
611 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
612 netlink_lock_table();
613 }
614 #endif
615 if (nl_table[protocol].registered &&
616 try_module_get(nl_table[protocol].module))
617 module = nl_table[protocol].module;
618 else
619 err = -EPROTONOSUPPORT;
620 cb_mutex = nl_table[protocol].cb_mutex;
621 bind = nl_table[protocol].bind;
622 unbind = nl_table[protocol].unbind;
623 netlink_unlock_table();
624
625 if (err < 0)
626 goto out;
627
628 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
629 if (err < 0)
630 goto out_module;
631
632 local_bh_disable();
633 sock_prot_inuse_add(net, &netlink_proto, 1);
634 local_bh_enable();
635
636 nlk = nlk_sk(sock->sk);
637 nlk->module = module;
638 nlk->netlink_bind = bind;
639 nlk->netlink_unbind = unbind;
640 out:
641 return err;
642
643 out_module:
644 module_put(module);
645 goto out;
646 }
647
648 static void deferred_put_nlk_sk(struct rcu_head *head)
649 {
650 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
651
652 sock_put(&nlk->sk);
653 }
654
655 static int netlink_release(struct socket *sock)
656 {
657 struct sock *sk = sock->sk;
658 struct netlink_sock *nlk;
659
660 if (!sk)
661 return 0;
662
663 netlink_remove(sk);
664 sock_orphan(sk);
665 nlk = nlk_sk(sk);
666
667 /*
668 * OK. Socket is unlinked, any packets that arrive now
669 * will be purged.
670 */
671
672 /* must not acquire netlink_table_lock in any way again before unbind
673 * and notifying genetlink is done as otherwise it might deadlock
674 */
675 if (nlk->netlink_unbind) {
676 int i;
677
678 for (i = 0; i < nlk->ngroups; i++)
679 if (test_bit(i, nlk->groups))
680 nlk->netlink_unbind(sock_net(sk), i + 1);
681 }
682 if (sk->sk_protocol == NETLINK_GENERIC &&
683 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
684 wake_up(&genl_sk_destructing_waitq);
685
686 sock->sk = NULL;
687 wake_up_interruptible_all(&nlk->wait);
688
689 skb_queue_purge(&sk->sk_write_queue);
690
691 if (nlk->portid) {
692 struct netlink_notify n = {
693 .net = sock_net(sk),
694 .protocol = sk->sk_protocol,
695 .portid = nlk->portid,
696 };
697 atomic_notifier_call_chain(&netlink_chain,
698 NETLINK_URELEASE, &n);
699 }
700
701 module_put(nlk->module);
702
703 if (netlink_is_kernel(sk)) {
704 netlink_table_grab();
705 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
706 if (--nl_table[sk->sk_protocol].registered == 0) {
707 struct listeners *old;
708
709 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
710 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
711 kfree_rcu(old, rcu);
712 nl_table[sk->sk_protocol].module = NULL;
713 nl_table[sk->sk_protocol].bind = NULL;
714 nl_table[sk->sk_protocol].unbind = NULL;
715 nl_table[sk->sk_protocol].flags = 0;
716 nl_table[sk->sk_protocol].registered = 0;
717 }
718 netlink_table_ungrab();
719 }
720
721 kfree(nlk->groups);
722 nlk->groups = NULL;
723
724 local_bh_disable();
725 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
726 local_bh_enable();
727 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
728 return 0;
729 }
730
731 static int netlink_autobind(struct socket *sock)
732 {
733 struct sock *sk = sock->sk;
734 struct net *net = sock_net(sk);
735 struct netlink_table *table = &nl_table[sk->sk_protocol];
736 s32 portid = task_tgid_vnr(current);
737 int err;
738 s32 rover = -4096;
739 bool ok;
740
741 retry:
742 cond_resched();
743 rcu_read_lock();
744 ok = !__netlink_lookup(table, portid, net);
745 rcu_read_unlock();
746 if (!ok) {
747 /* Bind collision, search negative portid values. */
748 if (rover == -4096)
749 /* rover will be in range [S32_MIN, -4097] */
750 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
751 else if (rover >= -4096)
752 rover = -4097;
753 portid = rover--;
754 goto retry;
755 }
756
757 err = netlink_insert(sk, portid);
758 if (err == -EADDRINUSE)
759 goto retry;
760
761 /* If 2 threads race to autobind, that is fine. */
762 if (err == -EBUSY)
763 err = 0;
764
765 return err;
766 }
767
768 /**
769 * __netlink_ns_capable - General netlink message capability test
770 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
771 * @user_ns: The user namespace of the capability to use
772 * @cap: The capability to use
773 *
774 * Test to see if the opener of the socket we received the message
775 * from had when the netlink socket was created and the sender of the
776 * message has has the capability @cap in the user namespace @user_ns.
777 */
778 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
779 struct user_namespace *user_ns, int cap)
780 {
781 return ((nsp->flags & NETLINK_SKB_DST) ||
782 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
783 ns_capable(user_ns, cap);
784 }
785 EXPORT_SYMBOL(__netlink_ns_capable);
786
787 /**
788 * netlink_ns_capable - General netlink message capability test
789 * @skb: socket buffer holding a netlink command from userspace
790 * @user_ns: The user namespace of the capability to use
791 * @cap: The capability to use
792 *
793 * Test to see if the opener of the socket we received the message
794 * from had when the netlink socket was created and the sender of the
795 * message has has the capability @cap in the user namespace @user_ns.
796 */
797 bool netlink_ns_capable(const struct sk_buff *skb,
798 struct user_namespace *user_ns, int cap)
799 {
800 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
801 }
802 EXPORT_SYMBOL(netlink_ns_capable);
803
804 /**
805 * netlink_capable - Netlink global message capability test
806 * @skb: socket buffer holding a netlink command from userspace
807 * @cap: The capability to use
808 *
809 * Test to see if the opener of the socket we received the message
810 * from had when the netlink socket was created and the sender of the
811 * message has has the capability @cap in all user namespaces.
812 */
813 bool netlink_capable(const struct sk_buff *skb, int cap)
814 {
815 return netlink_ns_capable(skb, &init_user_ns, cap);
816 }
817 EXPORT_SYMBOL(netlink_capable);
818
819 /**
820 * netlink_net_capable - Netlink network namespace message capability test
821 * @skb: socket buffer holding a netlink command from userspace
822 * @cap: The capability to use
823 *
824 * Test to see if the opener of the socket we received the message
825 * from had when the netlink socket was created and the sender of the
826 * message has has the capability @cap over the network namespace of
827 * the socket we received the message from.
828 */
829 bool netlink_net_capable(const struct sk_buff *skb, int cap)
830 {
831 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
832 }
833 EXPORT_SYMBOL(netlink_net_capable);
834
835 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
836 {
837 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
838 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
839 }
840
841 static void
842 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
843 {
844 struct netlink_sock *nlk = nlk_sk(sk);
845
846 if (nlk->subscriptions && !subscriptions)
847 __sk_del_bind_node(sk);
848 else if (!nlk->subscriptions && subscriptions)
849 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
850 nlk->subscriptions = subscriptions;
851 }
852
853 static int netlink_realloc_groups(struct sock *sk)
854 {
855 struct netlink_sock *nlk = nlk_sk(sk);
856 unsigned int groups;
857 unsigned long *new_groups;
858 int err = 0;
859
860 netlink_table_grab();
861
862 groups = nl_table[sk->sk_protocol].groups;
863 if (!nl_table[sk->sk_protocol].registered) {
864 err = -ENOENT;
865 goto out_unlock;
866 }
867
868 if (nlk->ngroups >= groups)
869 goto out_unlock;
870
871 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
872 if (new_groups == NULL) {
873 err = -ENOMEM;
874 goto out_unlock;
875 }
876 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
877 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
878
879 nlk->groups = new_groups;
880 nlk->ngroups = groups;
881 out_unlock:
882 netlink_table_ungrab();
883 return err;
884 }
885
886 static void netlink_undo_bind(int group, long unsigned int groups,
887 struct sock *sk)
888 {
889 struct netlink_sock *nlk = nlk_sk(sk);
890 int undo;
891
892 if (!nlk->netlink_unbind)
893 return;
894
895 for (undo = 0; undo < group; undo++)
896 if (test_bit(undo, &groups))
897 nlk->netlink_unbind(sock_net(sk), undo + 1);
898 }
899
900 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
901 int addr_len)
902 {
903 struct sock *sk = sock->sk;
904 struct net *net = sock_net(sk);
905 struct netlink_sock *nlk = nlk_sk(sk);
906 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
907 int err;
908 long unsigned int groups = nladdr->nl_groups;
909 bool bound;
910
911 if (addr_len < sizeof(struct sockaddr_nl))
912 return -EINVAL;
913
914 if (nladdr->nl_family != AF_NETLINK)
915 return -EINVAL;
916
917 /* Only superuser is allowed to listen multicasts */
918 if (groups) {
919 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
920 return -EPERM;
921 err = netlink_realloc_groups(sk);
922 if (err)
923 return err;
924 }
925
926 bound = nlk->bound;
927 if (bound) {
928 /* Ensure nlk->portid is up-to-date. */
929 smp_rmb();
930
931 if (nladdr->nl_pid != nlk->portid)
932 return -EINVAL;
933 }
934
935 if (nlk->netlink_bind && groups) {
936 int group;
937
938 for (group = 0; group < nlk->ngroups; group++) {
939 if (!test_bit(group, &groups))
940 continue;
941 err = nlk->netlink_bind(net, group + 1);
942 if (!err)
943 continue;
944 netlink_undo_bind(group, groups, sk);
945 return err;
946 }
947 }
948
949 /* No need for barriers here as we return to user-space without
950 * using any of the bound attributes.
951 */
952 if (!bound) {
953 err = nladdr->nl_pid ?
954 netlink_insert(sk, nladdr->nl_pid) :
955 netlink_autobind(sock);
956 if (err) {
957 netlink_undo_bind(nlk->ngroups, groups, sk);
958 return err;
959 }
960 }
961
962 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
963 return 0;
964
965 netlink_table_grab();
966 netlink_update_subscriptions(sk, nlk->subscriptions +
967 hweight32(groups) -
968 hweight32(nlk->groups[0]));
969 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
970 netlink_update_listeners(sk);
971 netlink_table_ungrab();
972
973 return 0;
974 }
975
976 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
977 int alen, int flags)
978 {
979 int err = 0;
980 struct sock *sk = sock->sk;
981 struct netlink_sock *nlk = nlk_sk(sk);
982 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
983
984 if (alen < sizeof(addr->sa_family))
985 return -EINVAL;
986
987 if (addr->sa_family == AF_UNSPEC) {
988 sk->sk_state = NETLINK_UNCONNECTED;
989 nlk->dst_portid = 0;
990 nlk->dst_group = 0;
991 return 0;
992 }
993 if (addr->sa_family != AF_NETLINK)
994 return -EINVAL;
995
996 if ((nladdr->nl_groups || nladdr->nl_pid) &&
997 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
998 return -EPERM;
999
1000 /* No need for barriers here as we return to user-space without
1001 * using any of the bound attributes.
1002 */
1003 if (!nlk->bound)
1004 err = netlink_autobind(sock);
1005
1006 if (err == 0) {
1007 sk->sk_state = NETLINK_CONNECTED;
1008 nlk->dst_portid = nladdr->nl_pid;
1009 nlk->dst_group = ffs(nladdr->nl_groups);
1010 }
1011
1012 return err;
1013 }
1014
1015 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1016 int *addr_len, int peer)
1017 {
1018 struct sock *sk = sock->sk;
1019 struct netlink_sock *nlk = nlk_sk(sk);
1020 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1021
1022 nladdr->nl_family = AF_NETLINK;
1023 nladdr->nl_pad = 0;
1024 *addr_len = sizeof(*nladdr);
1025
1026 if (peer) {
1027 nladdr->nl_pid = nlk->dst_portid;
1028 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1029 } else {
1030 nladdr->nl_pid = nlk->portid;
1031 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1032 }
1033 return 0;
1034 }
1035
1036 static int netlink_ioctl(struct socket *sock, unsigned int cmd,
1037 unsigned long arg)
1038 {
1039 /* try to hand this ioctl down to the NIC drivers.
1040 */
1041 return -ENOIOCTLCMD;
1042 }
1043
1044 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1045 {
1046 struct sock *sock;
1047 struct netlink_sock *nlk;
1048
1049 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1050 if (!sock)
1051 return ERR_PTR(-ECONNREFUSED);
1052
1053 /* Don't bother queuing skb if kernel socket has no input function */
1054 nlk = nlk_sk(sock);
1055 if (sock->sk_state == NETLINK_CONNECTED &&
1056 nlk->dst_portid != nlk_sk(ssk)->portid) {
1057 sock_put(sock);
1058 return ERR_PTR(-ECONNREFUSED);
1059 }
1060 return sock;
1061 }
1062
1063 struct sock *netlink_getsockbyfilp(struct file *filp)
1064 {
1065 struct inode *inode = file_inode(filp);
1066 struct sock *sock;
1067
1068 if (!S_ISSOCK(inode->i_mode))
1069 return ERR_PTR(-ENOTSOCK);
1070
1071 sock = SOCKET_I(inode)->sk;
1072 if (sock->sk_family != AF_NETLINK)
1073 return ERR_PTR(-EINVAL);
1074
1075 sock_hold(sock);
1076 return sock;
1077 }
1078
1079 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1080 int broadcast)
1081 {
1082 struct sk_buff *skb;
1083 void *data;
1084
1085 if (size <= NLMSG_GOODSIZE || broadcast)
1086 return alloc_skb(size, GFP_KERNEL);
1087
1088 size = SKB_DATA_ALIGN(size) +
1089 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1090
1091 data = vmalloc(size);
1092 if (data == NULL)
1093 return NULL;
1094
1095 skb = __build_skb(data, size);
1096 if (skb == NULL)
1097 vfree(data);
1098 else
1099 skb->destructor = netlink_skb_destructor;
1100
1101 return skb;
1102 }
1103
1104 /*
1105 * Attach a skb to a netlink socket.
1106 * The caller must hold a reference to the destination socket. On error, the
1107 * reference is dropped. The skb is not send to the destination, just all
1108 * all error checks are performed and memory in the queue is reserved.
1109 * Return values:
1110 * < 0: error. skb freed, reference to sock dropped.
1111 * 0: continue
1112 * 1: repeat lookup - reference dropped while waiting for socket memory.
1113 */
1114 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1115 long *timeo, struct sock *ssk)
1116 {
1117 struct netlink_sock *nlk;
1118
1119 nlk = nlk_sk(sk);
1120
1121 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1122 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1123 DECLARE_WAITQUEUE(wait, current);
1124 if (!*timeo) {
1125 if (!ssk || netlink_is_kernel(ssk))
1126 netlink_overrun(sk);
1127 sock_put(sk);
1128 kfree_skb(skb);
1129 return -EAGAIN;
1130 }
1131
1132 __set_current_state(TASK_INTERRUPTIBLE);
1133 add_wait_queue(&nlk->wait, &wait);
1134
1135 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1136 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1137 !sock_flag(sk, SOCK_DEAD))
1138 *timeo = schedule_timeout(*timeo);
1139
1140 __set_current_state(TASK_RUNNING);
1141 remove_wait_queue(&nlk->wait, &wait);
1142 sock_put(sk);
1143
1144 if (signal_pending(current)) {
1145 kfree_skb(skb);
1146 return sock_intr_errno(*timeo);
1147 }
1148 return 1;
1149 }
1150 netlink_skb_set_owner_r(skb, sk);
1151 return 0;
1152 }
1153
1154 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1155 {
1156 int len = skb->len;
1157
1158 netlink_deliver_tap(skb);
1159
1160 skb_queue_tail(&sk->sk_receive_queue, skb);
1161 sk->sk_data_ready(sk);
1162 return len;
1163 }
1164
1165 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1166 {
1167 int len = __netlink_sendskb(sk, skb);
1168
1169 sock_put(sk);
1170 return len;
1171 }
1172
1173 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1174 {
1175 kfree_skb(skb);
1176 sock_put(sk);
1177 }
1178
1179 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1180 {
1181 int delta;
1182
1183 WARN_ON(skb->sk != NULL);
1184 delta = skb->end - skb->tail;
1185 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1186 return skb;
1187
1188 if (skb_shared(skb)) {
1189 struct sk_buff *nskb = skb_clone(skb, allocation);
1190 if (!nskb)
1191 return skb;
1192 consume_skb(skb);
1193 skb = nskb;
1194 }
1195
1196 if (!pskb_expand_head(skb, 0, -delta, allocation))
1197 skb->truesize -= delta;
1198
1199 return skb;
1200 }
1201
1202 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1203 struct sock *ssk)
1204 {
1205 int ret;
1206 struct netlink_sock *nlk = nlk_sk(sk);
1207
1208 ret = -ECONNREFUSED;
1209 if (nlk->netlink_rcv != NULL) {
1210 ret = skb->len;
1211 netlink_skb_set_owner_r(skb, sk);
1212 NETLINK_CB(skb).sk = ssk;
1213 netlink_deliver_tap_kernel(sk, ssk, skb);
1214 nlk->netlink_rcv(skb);
1215 consume_skb(skb);
1216 } else {
1217 kfree_skb(skb);
1218 }
1219 sock_put(sk);
1220 return ret;
1221 }
1222
1223 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1224 u32 portid, int nonblock)
1225 {
1226 struct sock *sk;
1227 int err;
1228 long timeo;
1229
1230 skb = netlink_trim(skb, gfp_any());
1231
1232 timeo = sock_sndtimeo(ssk, nonblock);
1233 retry:
1234 sk = netlink_getsockbyportid(ssk, portid);
1235 if (IS_ERR(sk)) {
1236 kfree_skb(skb);
1237 return PTR_ERR(sk);
1238 }
1239 if (netlink_is_kernel(sk))
1240 return netlink_unicast_kernel(sk, skb, ssk);
1241
1242 if (sk_filter(sk, skb)) {
1243 err = skb->len;
1244 kfree_skb(skb);
1245 sock_put(sk);
1246 return err;
1247 }
1248
1249 err = netlink_attachskb(sk, skb, &timeo, ssk);
1250 if (err == 1)
1251 goto retry;
1252 if (err)
1253 return err;
1254
1255 return netlink_sendskb(sk, skb);
1256 }
1257 EXPORT_SYMBOL(netlink_unicast);
1258
1259 int netlink_has_listeners(struct sock *sk, unsigned int group)
1260 {
1261 int res = 0;
1262 struct listeners *listeners;
1263
1264 BUG_ON(!netlink_is_kernel(sk));
1265
1266 rcu_read_lock();
1267 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1268
1269 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1270 res = test_bit(group - 1, listeners->masks);
1271
1272 rcu_read_unlock();
1273
1274 return res;
1275 }
1276 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1277
1278 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1279 {
1280 struct netlink_sock *nlk = nlk_sk(sk);
1281
1282 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1283 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1284 netlink_skb_set_owner_r(skb, sk);
1285 __netlink_sendskb(sk, skb);
1286 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1287 }
1288 return -1;
1289 }
1290
1291 struct netlink_broadcast_data {
1292 struct sock *exclude_sk;
1293 struct net *net;
1294 u32 portid;
1295 u32 group;
1296 int failure;
1297 int delivery_failure;
1298 int congested;
1299 int delivered;
1300 gfp_t allocation;
1301 struct sk_buff *skb, *skb2;
1302 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1303 void *tx_data;
1304 };
1305
1306 static void do_one_broadcast(struct sock *sk,
1307 struct netlink_broadcast_data *p)
1308 {
1309 struct netlink_sock *nlk = nlk_sk(sk);
1310 int val;
1311
1312 if (p->exclude_sk == sk)
1313 return;
1314
1315 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1316 !test_bit(p->group - 1, nlk->groups))
1317 return;
1318
1319 if (!net_eq(sock_net(sk), p->net)) {
1320 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1321 return;
1322
1323 if (!peernet_has_id(sock_net(sk), p->net))
1324 return;
1325
1326 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1327 CAP_NET_BROADCAST))
1328 return;
1329 }
1330
1331 if (p->failure) {
1332 netlink_overrun(sk);
1333 return;
1334 }
1335
1336 sock_hold(sk);
1337 if (p->skb2 == NULL) {
1338 if (skb_shared(p->skb)) {
1339 p->skb2 = skb_clone(p->skb, p->allocation);
1340 } else {
1341 p->skb2 = skb_get(p->skb);
1342 /*
1343 * skb ownership may have been set when
1344 * delivered to a previous socket.
1345 */
1346 skb_orphan(p->skb2);
1347 }
1348 }
1349 if (p->skb2 == NULL) {
1350 netlink_overrun(sk);
1351 /* Clone failed. Notify ALL listeners. */
1352 p->failure = 1;
1353 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1354 p->delivery_failure = 1;
1355 goto out;
1356 }
1357 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1358 kfree_skb(p->skb2);
1359 p->skb2 = NULL;
1360 goto out;
1361 }
1362 if (sk_filter(sk, p->skb2)) {
1363 kfree_skb(p->skb2);
1364 p->skb2 = NULL;
1365 goto out;
1366 }
1367 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1368 NETLINK_CB(p->skb2).nsid_is_set = true;
1369 val = netlink_broadcast_deliver(sk, p->skb2);
1370 if (val < 0) {
1371 netlink_overrun(sk);
1372 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1373 p->delivery_failure = 1;
1374 } else {
1375 p->congested |= val;
1376 p->delivered = 1;
1377 p->skb2 = NULL;
1378 }
1379 out:
1380 sock_put(sk);
1381 }
1382
1383 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1384 u32 group, gfp_t allocation,
1385 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1386 void *filter_data)
1387 {
1388 struct net *net = sock_net(ssk);
1389 struct netlink_broadcast_data info;
1390 struct sock *sk;
1391
1392 skb = netlink_trim(skb, allocation);
1393
1394 info.exclude_sk = ssk;
1395 info.net = net;
1396 info.portid = portid;
1397 info.group = group;
1398 info.failure = 0;
1399 info.delivery_failure = 0;
1400 info.congested = 0;
1401 info.delivered = 0;
1402 info.allocation = allocation;
1403 info.skb = skb;
1404 info.skb2 = NULL;
1405 info.tx_filter = filter;
1406 info.tx_data = filter_data;
1407
1408 /* While we sleep in clone, do not allow to change socket list */
1409
1410 netlink_lock_table();
1411
1412 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1413 do_one_broadcast(sk, &info);
1414
1415 consume_skb(skb);
1416
1417 netlink_unlock_table();
1418
1419 if (info.delivery_failure) {
1420 kfree_skb(info.skb2);
1421 return -ENOBUFS;
1422 }
1423 consume_skb(info.skb2);
1424
1425 if (info.delivered) {
1426 if (info.congested && gfpflags_allow_blocking(allocation))
1427 yield();
1428 return 0;
1429 }
1430 return -ESRCH;
1431 }
1432 EXPORT_SYMBOL(netlink_broadcast_filtered);
1433
1434 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1435 u32 group, gfp_t allocation)
1436 {
1437 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1438 NULL, NULL);
1439 }
1440 EXPORT_SYMBOL(netlink_broadcast);
1441
1442 struct netlink_set_err_data {
1443 struct sock *exclude_sk;
1444 u32 portid;
1445 u32 group;
1446 int code;
1447 };
1448
1449 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1450 {
1451 struct netlink_sock *nlk = nlk_sk(sk);
1452 int ret = 0;
1453
1454 if (sk == p->exclude_sk)
1455 goto out;
1456
1457 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1458 goto out;
1459
1460 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1461 !test_bit(p->group - 1, nlk->groups))
1462 goto out;
1463
1464 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1465 ret = 1;
1466 goto out;
1467 }
1468
1469 sk->sk_err = p->code;
1470 sk->sk_error_report(sk);
1471 out:
1472 return ret;
1473 }
1474
1475 /**
1476 * netlink_set_err - report error to broadcast listeners
1477 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1478 * @portid: the PORTID of a process that we want to skip (if any)
1479 * @group: the broadcast group that will notice the error
1480 * @code: error code, must be negative (as usual in kernelspace)
1481 *
1482 * This function returns the number of broadcast listeners that have set the
1483 * NETLINK_NO_ENOBUFS socket option.
1484 */
1485 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1486 {
1487 struct netlink_set_err_data info;
1488 struct sock *sk;
1489 int ret = 0;
1490
1491 info.exclude_sk = ssk;
1492 info.portid = portid;
1493 info.group = group;
1494 /* sk->sk_err wants a positive error value */
1495 info.code = -code;
1496
1497 read_lock(&nl_table_lock);
1498
1499 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1500 ret += do_one_set_err(sk, &info);
1501
1502 read_unlock(&nl_table_lock);
1503 return ret;
1504 }
1505 EXPORT_SYMBOL(netlink_set_err);
1506
1507 /* must be called with netlink table grabbed */
1508 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1509 unsigned int group,
1510 int is_new)
1511 {
1512 int old, new = !!is_new, subscriptions;
1513
1514 old = test_bit(group - 1, nlk->groups);
1515 subscriptions = nlk->subscriptions - old + new;
1516 if (new)
1517 __set_bit(group - 1, nlk->groups);
1518 else
1519 __clear_bit(group - 1, nlk->groups);
1520 netlink_update_subscriptions(&nlk->sk, subscriptions);
1521 netlink_update_listeners(&nlk->sk);
1522 }
1523
1524 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1525 char __user *optval, unsigned int optlen)
1526 {
1527 struct sock *sk = sock->sk;
1528 struct netlink_sock *nlk = nlk_sk(sk);
1529 unsigned int val = 0;
1530 int err;
1531
1532 if (level != SOL_NETLINK)
1533 return -ENOPROTOOPT;
1534
1535 if (optlen >= sizeof(int) &&
1536 get_user(val, (unsigned int __user *)optval))
1537 return -EFAULT;
1538
1539 switch (optname) {
1540 case NETLINK_PKTINFO:
1541 if (val)
1542 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1543 else
1544 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1545 err = 0;
1546 break;
1547 case NETLINK_ADD_MEMBERSHIP:
1548 case NETLINK_DROP_MEMBERSHIP: {
1549 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1550 return -EPERM;
1551 err = netlink_realloc_groups(sk);
1552 if (err)
1553 return err;
1554 if (!val || val - 1 >= nlk->ngroups)
1555 return -EINVAL;
1556 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1557 err = nlk->netlink_bind(sock_net(sk), val);
1558 if (err)
1559 return err;
1560 }
1561 netlink_table_grab();
1562 netlink_update_socket_mc(nlk, val,
1563 optname == NETLINK_ADD_MEMBERSHIP);
1564 netlink_table_ungrab();
1565 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1566 nlk->netlink_unbind(sock_net(sk), val);
1567
1568 err = 0;
1569 break;
1570 }
1571 case NETLINK_BROADCAST_ERROR:
1572 if (val)
1573 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1574 else
1575 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1576 err = 0;
1577 break;
1578 case NETLINK_NO_ENOBUFS:
1579 if (val) {
1580 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1581 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1582 wake_up_interruptible(&nlk->wait);
1583 } else {
1584 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1585 }
1586 err = 0;
1587 break;
1588 case NETLINK_LISTEN_ALL_NSID:
1589 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1590 return -EPERM;
1591
1592 if (val)
1593 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1594 else
1595 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1596 err = 0;
1597 break;
1598 case NETLINK_CAP_ACK:
1599 if (val)
1600 nlk->flags |= NETLINK_F_CAP_ACK;
1601 else
1602 nlk->flags &= ~NETLINK_F_CAP_ACK;
1603 err = 0;
1604 break;
1605 default:
1606 err = -ENOPROTOOPT;
1607 }
1608 return err;
1609 }
1610
1611 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1612 char __user *optval, int __user *optlen)
1613 {
1614 struct sock *sk = sock->sk;
1615 struct netlink_sock *nlk = nlk_sk(sk);
1616 int len, val, err;
1617
1618 if (level != SOL_NETLINK)
1619 return -ENOPROTOOPT;
1620
1621 if (get_user(len, optlen))
1622 return -EFAULT;
1623 if (len < 0)
1624 return -EINVAL;
1625
1626 switch (optname) {
1627 case NETLINK_PKTINFO:
1628 if (len < sizeof(int))
1629 return -EINVAL;
1630 len = sizeof(int);
1631 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1632 if (put_user(len, optlen) ||
1633 put_user(val, optval))
1634 return -EFAULT;
1635 err = 0;
1636 break;
1637 case NETLINK_BROADCAST_ERROR:
1638 if (len < sizeof(int))
1639 return -EINVAL;
1640 len = sizeof(int);
1641 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1642 if (put_user(len, optlen) ||
1643 put_user(val, optval))
1644 return -EFAULT;
1645 err = 0;
1646 break;
1647 case NETLINK_NO_ENOBUFS:
1648 if (len < sizeof(int))
1649 return -EINVAL;
1650 len = sizeof(int);
1651 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1652 if (put_user(len, optlen) ||
1653 put_user(val, optval))
1654 return -EFAULT;
1655 err = 0;
1656 break;
1657 case NETLINK_LIST_MEMBERSHIPS: {
1658 int pos, idx, shift;
1659
1660 err = 0;
1661 netlink_lock_table();
1662 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1663 if (len - pos < sizeof(u32))
1664 break;
1665
1666 idx = pos / sizeof(unsigned long);
1667 shift = (pos % sizeof(unsigned long)) * 8;
1668 if (put_user((u32)(nlk->groups[idx] >> shift),
1669 (u32 __user *)(optval + pos))) {
1670 err = -EFAULT;
1671 break;
1672 }
1673 }
1674 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1675 err = -EFAULT;
1676 netlink_unlock_table();
1677 break;
1678 }
1679 case NETLINK_CAP_ACK:
1680 if (len < sizeof(int))
1681 return -EINVAL;
1682 len = sizeof(int);
1683 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1684 if (put_user(len, optlen) ||
1685 put_user(val, optval))
1686 return -EFAULT;
1687 err = 0;
1688 break;
1689 default:
1690 err = -ENOPROTOOPT;
1691 }
1692 return err;
1693 }
1694
1695 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1696 {
1697 struct nl_pktinfo info;
1698
1699 info.group = NETLINK_CB(skb).dst_group;
1700 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1701 }
1702
1703 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1704 struct sk_buff *skb)
1705 {
1706 if (!NETLINK_CB(skb).nsid_is_set)
1707 return;
1708
1709 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1710 &NETLINK_CB(skb).nsid);
1711 }
1712
1713 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1714 {
1715 struct sock *sk = sock->sk;
1716 struct netlink_sock *nlk = nlk_sk(sk);
1717 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1718 u32 dst_portid;
1719 u32 dst_group;
1720 struct sk_buff *skb;
1721 int err;
1722 struct scm_cookie scm;
1723 u32 netlink_skb_flags = 0;
1724
1725 if (msg->msg_flags&MSG_OOB)
1726 return -EOPNOTSUPP;
1727
1728 err = scm_send(sock, msg, &scm, true);
1729 if (err < 0)
1730 return err;
1731
1732 if (msg->msg_namelen) {
1733 err = -EINVAL;
1734 if (addr->nl_family != AF_NETLINK)
1735 goto out;
1736 dst_portid = addr->nl_pid;
1737 dst_group = ffs(addr->nl_groups);
1738 err = -EPERM;
1739 if ((dst_group || dst_portid) &&
1740 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1741 goto out;
1742 netlink_skb_flags |= NETLINK_SKB_DST;
1743 } else {
1744 dst_portid = nlk->dst_portid;
1745 dst_group = nlk->dst_group;
1746 }
1747
1748 if (!nlk->bound) {
1749 err = netlink_autobind(sock);
1750 if (err)
1751 goto out;
1752 } else {
1753 /* Ensure nlk is hashed and visible. */
1754 smp_rmb();
1755 }
1756
1757 err = -EMSGSIZE;
1758 if (len > sk->sk_sndbuf - 32)
1759 goto out;
1760 err = -ENOBUFS;
1761 skb = netlink_alloc_large_skb(len, dst_group);
1762 if (skb == NULL)
1763 goto out;
1764
1765 NETLINK_CB(skb).portid = nlk->portid;
1766 NETLINK_CB(skb).dst_group = dst_group;
1767 NETLINK_CB(skb).creds = scm.creds;
1768 NETLINK_CB(skb).flags = netlink_skb_flags;
1769
1770 err = -EFAULT;
1771 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1772 kfree_skb(skb);
1773 goto out;
1774 }
1775
1776 err = security_netlink_send(sk, skb);
1777 if (err) {
1778 kfree_skb(skb);
1779 goto out;
1780 }
1781
1782 if (dst_group) {
1783 atomic_inc(&skb->users);
1784 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1785 }
1786 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1787
1788 out:
1789 scm_destroy(&scm);
1790 return err;
1791 }
1792
1793 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1794 int flags)
1795 {
1796 struct scm_cookie scm;
1797 struct sock *sk = sock->sk;
1798 struct netlink_sock *nlk = nlk_sk(sk);
1799 int noblock = flags&MSG_DONTWAIT;
1800 size_t copied;
1801 struct sk_buff *skb, *data_skb;
1802 int err, ret;
1803
1804 if (flags&MSG_OOB)
1805 return -EOPNOTSUPP;
1806
1807 copied = 0;
1808
1809 skb = skb_recv_datagram(sk, flags, noblock, &err);
1810 if (skb == NULL)
1811 goto out;
1812
1813 data_skb = skb;
1814
1815 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1816 if (unlikely(skb_shinfo(skb)->frag_list)) {
1817 /*
1818 * If this skb has a frag_list, then here that means that we
1819 * will have to use the frag_list skb's data for compat tasks
1820 * and the regular skb's data for normal (non-compat) tasks.
1821 *
1822 * If we need to send the compat skb, assign it to the
1823 * 'data_skb' variable so that it will be used below for data
1824 * copying. We keep 'skb' for everything else, including
1825 * freeing both later.
1826 */
1827 if (flags & MSG_CMSG_COMPAT)
1828 data_skb = skb_shinfo(skb)->frag_list;
1829 }
1830 #endif
1831
1832 /* Record the max length of recvmsg() calls for future allocations */
1833 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1834 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1835 16384);
1836
1837 copied = data_skb->len;
1838 if (len < copied) {
1839 msg->msg_flags |= MSG_TRUNC;
1840 copied = len;
1841 }
1842
1843 skb_reset_transport_header(data_skb);
1844 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1845
1846 if (msg->msg_name) {
1847 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1848 addr->nl_family = AF_NETLINK;
1849 addr->nl_pad = 0;
1850 addr->nl_pid = NETLINK_CB(skb).portid;
1851 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1852 msg->msg_namelen = sizeof(*addr);
1853 }
1854
1855 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1856 netlink_cmsg_recv_pktinfo(msg, skb);
1857 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1858 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1859
1860 memset(&scm, 0, sizeof(scm));
1861 scm.creds = *NETLINK_CREDS(skb);
1862 if (flags & MSG_TRUNC)
1863 copied = data_skb->len;
1864
1865 skb_free_datagram(sk, skb);
1866
1867 if (nlk->cb_running &&
1868 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1869 ret = netlink_dump(sk);
1870 if (ret) {
1871 sk->sk_err = -ret;
1872 sk->sk_error_report(sk);
1873 }
1874 }
1875
1876 scm_recv(sock, msg, &scm, flags);
1877 out:
1878 netlink_rcv_wake(sk);
1879 return err ? : copied;
1880 }
1881
1882 static void netlink_data_ready(struct sock *sk)
1883 {
1884 BUG();
1885 }
1886
1887 /*
1888 * We export these functions to other modules. They provide a
1889 * complete set of kernel non-blocking support for message
1890 * queueing.
1891 */
1892
1893 struct sock *
1894 __netlink_kernel_create(struct net *net, int unit, struct module *module,
1895 struct netlink_kernel_cfg *cfg)
1896 {
1897 struct socket *sock;
1898 struct sock *sk;
1899 struct netlink_sock *nlk;
1900 struct listeners *listeners = NULL;
1901 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
1902 unsigned int groups;
1903
1904 BUG_ON(!nl_table);
1905
1906 if (unit < 0 || unit >= MAX_LINKS)
1907 return NULL;
1908
1909 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1910 return NULL;
1911
1912 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
1913 goto out_sock_release_nosk;
1914
1915 sk = sock->sk;
1916
1917 if (!cfg || cfg->groups < 32)
1918 groups = 32;
1919 else
1920 groups = cfg->groups;
1921
1922 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1923 if (!listeners)
1924 goto out_sock_release;
1925
1926 sk->sk_data_ready = netlink_data_ready;
1927 if (cfg && cfg->input)
1928 nlk_sk(sk)->netlink_rcv = cfg->input;
1929
1930 if (netlink_insert(sk, 0))
1931 goto out_sock_release;
1932
1933 nlk = nlk_sk(sk);
1934 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
1935
1936 netlink_table_grab();
1937 if (!nl_table[unit].registered) {
1938 nl_table[unit].groups = groups;
1939 rcu_assign_pointer(nl_table[unit].listeners, listeners);
1940 nl_table[unit].cb_mutex = cb_mutex;
1941 nl_table[unit].module = module;
1942 if (cfg) {
1943 nl_table[unit].bind = cfg->bind;
1944 nl_table[unit].unbind = cfg->unbind;
1945 nl_table[unit].flags = cfg->flags;
1946 if (cfg->compare)
1947 nl_table[unit].compare = cfg->compare;
1948 }
1949 nl_table[unit].registered = 1;
1950 } else {
1951 kfree(listeners);
1952 nl_table[unit].registered++;
1953 }
1954 netlink_table_ungrab();
1955 return sk;
1956
1957 out_sock_release:
1958 kfree(listeners);
1959 netlink_kernel_release(sk);
1960 return NULL;
1961
1962 out_sock_release_nosk:
1963 sock_release(sock);
1964 return NULL;
1965 }
1966 EXPORT_SYMBOL(__netlink_kernel_create);
1967
1968 void
1969 netlink_kernel_release(struct sock *sk)
1970 {
1971 if (sk == NULL || sk->sk_socket == NULL)
1972 return;
1973
1974 sock_release(sk->sk_socket);
1975 }
1976 EXPORT_SYMBOL(netlink_kernel_release);
1977
1978 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1979 {
1980 struct listeners *new, *old;
1981 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1982
1983 if (groups < 32)
1984 groups = 32;
1985
1986 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1987 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
1988 if (!new)
1989 return -ENOMEM;
1990 old = nl_deref_protected(tbl->listeners);
1991 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
1992 rcu_assign_pointer(tbl->listeners, new);
1993
1994 kfree_rcu(old, rcu);
1995 }
1996 tbl->groups = groups;
1997
1998 return 0;
1999 }
2000
2001 /**
2002 * netlink_change_ngroups - change number of multicast groups
2003 *
2004 * This changes the number of multicast groups that are available
2005 * on a certain netlink family. Note that it is not possible to
2006 * change the number of groups to below 32. Also note that it does
2007 * not implicitly call netlink_clear_multicast_users() when the
2008 * number of groups is reduced.
2009 *
2010 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2011 * @groups: The new number of groups.
2012 */
2013 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2014 {
2015 int err;
2016
2017 netlink_table_grab();
2018 err = __netlink_change_ngroups(sk, groups);
2019 netlink_table_ungrab();
2020
2021 return err;
2022 }
2023
2024 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2025 {
2026 struct sock *sk;
2027 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2028
2029 sk_for_each_bound(sk, &tbl->mc_list)
2030 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2031 }
2032
2033 struct nlmsghdr *
2034 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2035 {
2036 struct nlmsghdr *nlh;
2037 int size = nlmsg_msg_size(len);
2038
2039 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2040 nlh->nlmsg_type = type;
2041 nlh->nlmsg_len = size;
2042 nlh->nlmsg_flags = flags;
2043 nlh->nlmsg_pid = portid;
2044 nlh->nlmsg_seq = seq;
2045 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2046 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2047 return nlh;
2048 }
2049 EXPORT_SYMBOL(__nlmsg_put);
2050
2051 /*
2052 * It looks a bit ugly.
2053 * It would be better to create kernel thread.
2054 */
2055
2056 static int netlink_dump(struct sock *sk)
2057 {
2058 struct netlink_sock *nlk = nlk_sk(sk);
2059 struct netlink_callback *cb;
2060 struct sk_buff *skb = NULL;
2061 struct nlmsghdr *nlh;
2062 int len, err = -ENOBUFS;
2063 int alloc_min_size;
2064 int alloc_size;
2065
2066 mutex_lock(nlk->cb_mutex);
2067 if (!nlk->cb_running) {
2068 err = -EINVAL;
2069 goto errout_skb;
2070 }
2071
2072 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2073 goto errout_skb;
2074
2075 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2076 * required, but it makes sense to _attempt_ a 16K bytes allocation
2077 * to reduce number of system calls on dump operations, if user
2078 * ever provided a big enough buffer.
2079 */
2080 cb = &nlk->cb;
2081 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2082
2083 if (alloc_min_size < nlk->max_recvmsg_len) {
2084 alloc_size = nlk->max_recvmsg_len;
2085 skb = alloc_skb(alloc_size, GFP_KERNEL |
2086 __GFP_NOWARN | __GFP_NORETRY);
2087 }
2088 if (!skb) {
2089 alloc_size = alloc_min_size;
2090 skb = alloc_skb(alloc_size, GFP_KERNEL);
2091 }
2092 if (!skb)
2093 goto errout_skb;
2094
2095 /* Trim skb to allocated size. User is expected to provide buffer as
2096 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2097 * netlink_recvmsg())). dump will pack as many smaller messages as
2098 * could fit within the allocated skb. skb is typically allocated
2099 * with larger space than required (could be as much as near 2x the
2100 * requested size with align to next power of 2 approach). Allowing
2101 * dump to use the excess space makes it difficult for a user to have a
2102 * reasonable static buffer based on the expected largest dump of a
2103 * single netdev. The outcome is MSG_TRUNC error.
2104 */
2105 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2106 netlink_skb_set_owner_r(skb, sk);
2107
2108 len = cb->dump(skb, cb);
2109
2110 if (len > 0) {
2111 mutex_unlock(nlk->cb_mutex);
2112
2113 if (sk_filter(sk, skb))
2114 kfree_skb(skb);
2115 else
2116 __netlink_sendskb(sk, skb);
2117 return 0;
2118 }
2119
2120 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2121 if (!nlh)
2122 goto errout_skb;
2123
2124 nl_dump_check_consistent(cb, nlh);
2125
2126 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2127
2128 if (sk_filter(sk, skb))
2129 kfree_skb(skb);
2130 else
2131 __netlink_sendskb(sk, skb);
2132
2133 if (cb->done)
2134 cb->done(cb);
2135
2136 nlk->cb_running = false;
2137 mutex_unlock(nlk->cb_mutex);
2138 module_put(cb->module);
2139 consume_skb(cb->skb);
2140 return 0;
2141
2142 errout_skb:
2143 mutex_unlock(nlk->cb_mutex);
2144 kfree_skb(skb);
2145 return err;
2146 }
2147
2148 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2149 const struct nlmsghdr *nlh,
2150 struct netlink_dump_control *control)
2151 {
2152 struct netlink_callback *cb;
2153 struct sock *sk;
2154 struct netlink_sock *nlk;
2155 int ret;
2156
2157 atomic_inc(&skb->users);
2158
2159 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2160 if (sk == NULL) {
2161 ret = -ECONNREFUSED;
2162 goto error_free;
2163 }
2164
2165 nlk = nlk_sk(sk);
2166 mutex_lock(nlk->cb_mutex);
2167 /* A dump is in progress... */
2168 if (nlk->cb_running) {
2169 ret = -EBUSY;
2170 goto error_unlock;
2171 }
2172 /* add reference of module which cb->dump belongs to */
2173 if (!try_module_get(control->module)) {
2174 ret = -EPROTONOSUPPORT;
2175 goto error_unlock;
2176 }
2177
2178 cb = &nlk->cb;
2179 memset(cb, 0, sizeof(*cb));
2180 cb->start = control->start;
2181 cb->dump = control->dump;
2182 cb->done = control->done;
2183 cb->nlh = nlh;
2184 cb->data = control->data;
2185 cb->module = control->module;
2186 cb->min_dump_alloc = control->min_dump_alloc;
2187 cb->skb = skb;
2188
2189 nlk->cb_running = true;
2190
2191 mutex_unlock(nlk->cb_mutex);
2192
2193 if (cb->start)
2194 cb->start(cb);
2195
2196 ret = netlink_dump(sk);
2197 sock_put(sk);
2198
2199 if (ret)
2200 return ret;
2201
2202 /* We successfully started a dump, by returning -EINTR we
2203 * signal not to send ACK even if it was requested.
2204 */
2205 return -EINTR;
2206
2207 error_unlock:
2208 sock_put(sk);
2209 mutex_unlock(nlk->cb_mutex);
2210 error_free:
2211 kfree_skb(skb);
2212 return ret;
2213 }
2214 EXPORT_SYMBOL(__netlink_dump_start);
2215
2216 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2217 {
2218 struct sk_buff *skb;
2219 struct nlmsghdr *rep;
2220 struct nlmsgerr *errmsg;
2221 size_t payload = sizeof(*errmsg);
2222 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2223
2224 /* Error messages get the original request appened, unless the user
2225 * requests to cap the error message.
2226 */
2227 if (!(nlk->flags & NETLINK_F_CAP_ACK) && err)
2228 payload += nlmsg_len(nlh);
2229
2230 skb = nlmsg_new(payload, GFP_KERNEL);
2231 if (!skb) {
2232 struct sock *sk;
2233
2234 sk = netlink_lookup(sock_net(in_skb->sk),
2235 in_skb->sk->sk_protocol,
2236 NETLINK_CB(in_skb).portid);
2237 if (sk) {
2238 sk->sk_err = ENOBUFS;
2239 sk->sk_error_report(sk);
2240 sock_put(sk);
2241 }
2242 return;
2243 }
2244
2245 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2246 NLMSG_ERROR, payload, 0);
2247 errmsg = nlmsg_data(rep);
2248 errmsg->error = err;
2249 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2250 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2251 }
2252 EXPORT_SYMBOL(netlink_ack);
2253
2254 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2255 struct nlmsghdr *))
2256 {
2257 struct nlmsghdr *nlh;
2258 int err;
2259
2260 while (skb->len >= nlmsg_total_size(0)) {
2261 int msglen;
2262
2263 nlh = nlmsg_hdr(skb);
2264 err = 0;
2265
2266 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2267 return 0;
2268
2269 /* Only requests are handled by the kernel */
2270 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2271 goto ack;
2272
2273 /* Skip control messages */
2274 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2275 goto ack;
2276
2277 err = cb(skb, nlh);
2278 if (err == -EINTR)
2279 goto skip;
2280
2281 ack:
2282 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2283 netlink_ack(skb, nlh, err);
2284
2285 skip:
2286 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2287 if (msglen > skb->len)
2288 msglen = skb->len;
2289 skb_pull(skb, msglen);
2290 }
2291
2292 return 0;
2293 }
2294 EXPORT_SYMBOL(netlink_rcv_skb);
2295
2296 /**
2297 * nlmsg_notify - send a notification netlink message
2298 * @sk: netlink socket to use
2299 * @skb: notification message
2300 * @portid: destination netlink portid for reports or 0
2301 * @group: destination multicast group or 0
2302 * @report: 1 to report back, 0 to disable
2303 * @flags: allocation flags
2304 */
2305 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2306 unsigned int group, int report, gfp_t flags)
2307 {
2308 int err = 0;
2309
2310 if (group) {
2311 int exclude_portid = 0;
2312
2313 if (report) {
2314 atomic_inc(&skb->users);
2315 exclude_portid = portid;
2316 }
2317
2318 /* errors reported via destination sk->sk_err, but propagate
2319 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2320 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2321 }
2322
2323 if (report) {
2324 int err2;
2325
2326 err2 = nlmsg_unicast(sk, skb, portid);
2327 if (!err || err == -ESRCH)
2328 err = err2;
2329 }
2330
2331 return err;
2332 }
2333 EXPORT_SYMBOL(nlmsg_notify);
2334
2335 #ifdef CONFIG_PROC_FS
2336 struct nl_seq_iter {
2337 struct seq_net_private p;
2338 struct rhashtable_iter hti;
2339 int link;
2340 };
2341
2342 static int netlink_walk_start(struct nl_seq_iter *iter)
2343 {
2344 int err;
2345
2346 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti);
2347 if (err) {
2348 iter->link = MAX_LINKS;
2349 return err;
2350 }
2351
2352 err = rhashtable_walk_start(&iter->hti);
2353 return err == -EAGAIN ? 0 : err;
2354 }
2355
2356 static void netlink_walk_stop(struct nl_seq_iter *iter)
2357 {
2358 rhashtable_walk_stop(&iter->hti);
2359 rhashtable_walk_exit(&iter->hti);
2360 }
2361
2362 static void *__netlink_seq_next(struct seq_file *seq)
2363 {
2364 struct nl_seq_iter *iter = seq->private;
2365 struct netlink_sock *nlk;
2366
2367 do {
2368 for (;;) {
2369 int err;
2370
2371 nlk = rhashtable_walk_next(&iter->hti);
2372
2373 if (IS_ERR(nlk)) {
2374 if (PTR_ERR(nlk) == -EAGAIN)
2375 continue;
2376
2377 return nlk;
2378 }
2379
2380 if (nlk)
2381 break;
2382
2383 netlink_walk_stop(iter);
2384 if (++iter->link >= MAX_LINKS)
2385 return NULL;
2386
2387 err = netlink_walk_start(iter);
2388 if (err)
2389 return ERR_PTR(err);
2390 }
2391 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2392
2393 return nlk;
2394 }
2395
2396 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2397 {
2398 struct nl_seq_iter *iter = seq->private;
2399 void *obj = SEQ_START_TOKEN;
2400 loff_t pos;
2401 int err;
2402
2403 iter->link = 0;
2404
2405 err = netlink_walk_start(iter);
2406 if (err)
2407 return ERR_PTR(err);
2408
2409 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2410 obj = __netlink_seq_next(seq);
2411
2412 return obj;
2413 }
2414
2415 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2416 {
2417 ++*pos;
2418 return __netlink_seq_next(seq);
2419 }
2420
2421 static void netlink_seq_stop(struct seq_file *seq, void *v)
2422 {
2423 struct nl_seq_iter *iter = seq->private;
2424
2425 if (iter->link >= MAX_LINKS)
2426 return;
2427
2428 netlink_walk_stop(iter);
2429 }
2430
2431
2432 static int netlink_seq_show(struct seq_file *seq, void *v)
2433 {
2434 if (v == SEQ_START_TOKEN) {
2435 seq_puts(seq,
2436 "sk Eth Pid Groups "
2437 "Rmem Wmem Dump Locks Drops Inode\n");
2438 } else {
2439 struct sock *s = v;
2440 struct netlink_sock *nlk = nlk_sk(s);
2441
2442 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2443 s,
2444 s->sk_protocol,
2445 nlk->portid,
2446 nlk->groups ? (u32)nlk->groups[0] : 0,
2447 sk_rmem_alloc_get(s),
2448 sk_wmem_alloc_get(s),
2449 nlk->cb_running,
2450 atomic_read(&s->sk_refcnt),
2451 atomic_read(&s->sk_drops),
2452 sock_i_ino(s)
2453 );
2454
2455 }
2456 return 0;
2457 }
2458
2459 static const struct seq_operations netlink_seq_ops = {
2460 .start = netlink_seq_start,
2461 .next = netlink_seq_next,
2462 .stop = netlink_seq_stop,
2463 .show = netlink_seq_show,
2464 };
2465
2466
2467 static int netlink_seq_open(struct inode *inode, struct file *file)
2468 {
2469 return seq_open_net(inode, file, &netlink_seq_ops,
2470 sizeof(struct nl_seq_iter));
2471 }
2472
2473 static const struct file_operations netlink_seq_fops = {
2474 .owner = THIS_MODULE,
2475 .open = netlink_seq_open,
2476 .read = seq_read,
2477 .llseek = seq_lseek,
2478 .release = seq_release_net,
2479 };
2480
2481 #endif
2482
2483 int netlink_register_notifier(struct notifier_block *nb)
2484 {
2485 return atomic_notifier_chain_register(&netlink_chain, nb);
2486 }
2487 EXPORT_SYMBOL(netlink_register_notifier);
2488
2489 int netlink_unregister_notifier(struct notifier_block *nb)
2490 {
2491 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2492 }
2493 EXPORT_SYMBOL(netlink_unregister_notifier);
2494
2495 static const struct proto_ops netlink_ops = {
2496 .family = PF_NETLINK,
2497 .owner = THIS_MODULE,
2498 .release = netlink_release,
2499 .bind = netlink_bind,
2500 .connect = netlink_connect,
2501 .socketpair = sock_no_socketpair,
2502 .accept = sock_no_accept,
2503 .getname = netlink_getname,
2504 .poll = datagram_poll,
2505 .ioctl = netlink_ioctl,
2506 .listen = sock_no_listen,
2507 .shutdown = sock_no_shutdown,
2508 .setsockopt = netlink_setsockopt,
2509 .getsockopt = netlink_getsockopt,
2510 .sendmsg = netlink_sendmsg,
2511 .recvmsg = netlink_recvmsg,
2512 .mmap = sock_no_mmap,
2513 .sendpage = sock_no_sendpage,
2514 };
2515
2516 static const struct net_proto_family netlink_family_ops = {
2517 .family = PF_NETLINK,
2518 .create = netlink_create,
2519 .owner = THIS_MODULE, /* for consistency 8) */
2520 };
2521
2522 static int __net_init netlink_net_init(struct net *net)
2523 {
2524 #ifdef CONFIG_PROC_FS
2525 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
2526 return -ENOMEM;
2527 #endif
2528 return 0;
2529 }
2530
2531 static void __net_exit netlink_net_exit(struct net *net)
2532 {
2533 #ifdef CONFIG_PROC_FS
2534 remove_proc_entry("netlink", net->proc_net);
2535 #endif
2536 }
2537
2538 static void __init netlink_add_usersock_entry(void)
2539 {
2540 struct listeners *listeners;
2541 int groups = 32;
2542
2543 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2544 if (!listeners)
2545 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2546
2547 netlink_table_grab();
2548
2549 nl_table[NETLINK_USERSOCK].groups = groups;
2550 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2551 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2552 nl_table[NETLINK_USERSOCK].registered = 1;
2553 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2554
2555 netlink_table_ungrab();
2556 }
2557
2558 static struct pernet_operations __net_initdata netlink_net_ops = {
2559 .init = netlink_net_init,
2560 .exit = netlink_net_exit,
2561 };
2562
2563 static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2564 {
2565 const struct netlink_sock *nlk = data;
2566 struct netlink_compare_arg arg;
2567
2568 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2569 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2570 }
2571
2572 static const struct rhashtable_params netlink_rhashtable_params = {
2573 .head_offset = offsetof(struct netlink_sock, node),
2574 .key_len = netlink_compare_arg_len,
2575 .obj_hashfn = netlink_hash,
2576 .obj_cmpfn = netlink_compare,
2577 .automatic_shrinking = true,
2578 };
2579
2580 static int __init netlink_proto_init(void)
2581 {
2582 int i;
2583 int err = proto_register(&netlink_proto, 0);
2584
2585 if (err != 0)
2586 goto out;
2587
2588 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2589
2590 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2591 if (!nl_table)
2592 goto panic;
2593
2594 for (i = 0; i < MAX_LINKS; i++) {
2595 if (rhashtable_init(&nl_table[i].hash,
2596 &netlink_rhashtable_params) < 0) {
2597 while (--i > 0)
2598 rhashtable_destroy(&nl_table[i].hash);
2599 kfree(nl_table);
2600 goto panic;
2601 }
2602 }
2603
2604 INIT_LIST_HEAD(&netlink_tap_all);
2605
2606 netlink_add_usersock_entry();
2607
2608 sock_register(&netlink_family_ops);
2609 register_pernet_subsys(&netlink_net_ops);
2610 /* The netlink device handler may be needed early. */
2611 rtnetlink_init();
2612 out:
2613 return err;
2614 panic:
2615 panic("netlink_init: Cannot allocate nl_table\n");
2616 }
2617
2618 core_initcall(netlink_proto_init);
Linux kernel - Deliverables
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