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 #include <linux/nospec.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 /* flags */
83 #define NETLINK_F_KERNEL_SOCKET 0x1
84 #define NETLINK_F_RECV_PKTINFO 0x2
85 #define NETLINK_F_BROADCAST_SEND_ERROR 0x4
86 #define NETLINK_F_RECV_NO_ENOBUFS 0x8
87 #define NETLINK_F_LISTEN_ALL_NSID 0x10
88 #define NETLINK_F_CAP_ACK 0x20
89
netlink_is_kernel(struct sock * sk)90 static inline int netlink_is_kernel(struct sock *sk)
91 {
92 return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;
93 }
94
95 struct netlink_table *nl_table __read_mostly;
96 EXPORT_SYMBOL_GPL(nl_table);
97
98 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
99
100 static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
101
102 static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
103 "nlk_cb_mutex-ROUTE",
104 "nlk_cb_mutex-1",
105 "nlk_cb_mutex-USERSOCK",
106 "nlk_cb_mutex-FIREWALL",
107 "nlk_cb_mutex-SOCK_DIAG",
108 "nlk_cb_mutex-NFLOG",
109 "nlk_cb_mutex-XFRM",
110 "nlk_cb_mutex-SELINUX",
111 "nlk_cb_mutex-ISCSI",
112 "nlk_cb_mutex-AUDIT",
113 "nlk_cb_mutex-FIB_LOOKUP",
114 "nlk_cb_mutex-CONNECTOR",
115 "nlk_cb_mutex-NETFILTER",
116 "nlk_cb_mutex-IP6_FW",
117 "nlk_cb_mutex-DNRTMSG",
118 "nlk_cb_mutex-KOBJECT_UEVENT",
119 "nlk_cb_mutex-GENERIC",
120 "nlk_cb_mutex-17",
121 "nlk_cb_mutex-SCSITRANSPORT",
122 "nlk_cb_mutex-ECRYPTFS",
123 "nlk_cb_mutex-RDMA",
124 "nlk_cb_mutex-CRYPTO",
125 "nlk_cb_mutex-SMC",
126 "nlk_cb_mutex-23",
127 "nlk_cb_mutex-24",
128 "nlk_cb_mutex-25",
129 "nlk_cb_mutex-26",
130 "nlk_cb_mutex-27",
131 "nlk_cb_mutex-28",
132 "nlk_cb_mutex-29",
133 "nlk_cb_mutex-30",
134 "nlk_cb_mutex-31",
135 "nlk_cb_mutex-MAX_LINKS"
136 };
137
138 static int netlink_dump(struct sock *sk);
139 static void netlink_skb_destructor(struct sk_buff *skb);
140
141 /* nl_table locking explained:
142 * Lookup and traversal are protected with an RCU read-side lock. Insertion
143 * and removal are protected with per bucket lock while using RCU list
144 * modification primitives and may run in parallel to RCU protected lookups.
145 * Destruction of the Netlink socket may only occur *after* nl_table_lock has
146 * been acquired * either during or after the socket has been removed from
147 * the list and after an RCU grace period.
148 */
149 DEFINE_RWLOCK(nl_table_lock);
150 EXPORT_SYMBOL_GPL(nl_table_lock);
151 static atomic_t nl_table_users = ATOMIC_INIT(0);
152
153 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
154
155 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
156
157 static DEFINE_SPINLOCK(netlink_tap_lock);
158 static struct list_head netlink_tap_all __read_mostly;
159
160 static const struct rhashtable_params netlink_rhashtable_params;
161
netlink_group_mask(u32 group)162 static inline u32 netlink_group_mask(u32 group)
163 {
164 return group ? 1 << (group - 1) : 0;
165 }
166
netlink_to_full_skb(const struct sk_buff * skb,gfp_t gfp_mask)167 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
168 gfp_t gfp_mask)
169 {
170 unsigned int len = skb_end_offset(skb);
171 struct sk_buff *new;
172
173 new = alloc_skb(len, gfp_mask);
174 if (new == NULL)
175 return NULL;
176
177 NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
178 NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
179 NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
180
181 memcpy(skb_put(new, len), skb->data, len);
182 return new;
183 }
184
netlink_add_tap(struct netlink_tap * nt)185 int netlink_add_tap(struct netlink_tap *nt)
186 {
187 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
188 return -EINVAL;
189
190 spin_lock(&netlink_tap_lock);
191 list_add_rcu(&nt->list, &netlink_tap_all);
192 spin_unlock(&netlink_tap_lock);
193
194 __module_get(nt->module);
195
196 return 0;
197 }
198 EXPORT_SYMBOL_GPL(netlink_add_tap);
199
__netlink_remove_tap(struct netlink_tap * nt)200 static int __netlink_remove_tap(struct netlink_tap *nt)
201 {
202 bool found = false;
203 struct netlink_tap *tmp;
204
205 spin_lock(&netlink_tap_lock);
206
207 list_for_each_entry(tmp, &netlink_tap_all, list) {
208 if (nt == tmp) {
209 list_del_rcu(&nt->list);
210 found = true;
211 goto out;
212 }
213 }
214
215 pr_warn("__netlink_remove_tap: %p not found\n", nt);
216 out:
217 spin_unlock(&netlink_tap_lock);
218
219 if (found)
220 module_put(nt->module);
221
222 return found ? 0 : -ENODEV;
223 }
224
netlink_remove_tap(struct netlink_tap * nt)225 int netlink_remove_tap(struct netlink_tap *nt)
226 {
227 int ret;
228
229 ret = __netlink_remove_tap(nt);
230 synchronize_net();
231
232 return ret;
233 }
234 EXPORT_SYMBOL_GPL(netlink_remove_tap);
235
netlink_filter_tap(const struct sk_buff * skb)236 static bool netlink_filter_tap(const struct sk_buff *skb)
237 {
238 struct sock *sk = skb->sk;
239
240 /* We take the more conservative approach and
241 * whitelist socket protocols that may pass.
242 */
243 switch (sk->sk_protocol) {
244 case NETLINK_ROUTE:
245 case NETLINK_USERSOCK:
246 case NETLINK_SOCK_DIAG:
247 case NETLINK_NFLOG:
248 case NETLINK_XFRM:
249 case NETLINK_FIB_LOOKUP:
250 case NETLINK_NETFILTER:
251 case NETLINK_GENERIC:
252 return true;
253 }
254
255 return false;
256 }
257
__netlink_deliver_tap_skb(struct sk_buff * skb,struct net_device * dev)258 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
259 struct net_device *dev)
260 {
261 struct sk_buff *nskb;
262 struct sock *sk = skb->sk;
263 int ret = -ENOMEM;
264
265 if (!net_eq(dev_net(dev), sock_net(sk)))
266 return 0;
267
268 dev_hold(dev);
269
270 if (is_vmalloc_addr(skb->head))
271 nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
272 else
273 nskb = skb_clone(skb, GFP_ATOMIC);
274 if (nskb) {
275 nskb->dev = dev;
276 nskb->protocol = htons((u16) sk->sk_protocol);
277 nskb->pkt_type = netlink_is_kernel(sk) ?
278 PACKET_KERNEL : PACKET_USER;
279 skb_reset_network_header(nskb);
280 ret = dev_queue_xmit(nskb);
281 if (unlikely(ret > 0))
282 ret = net_xmit_errno(ret);
283 }
284
285 dev_put(dev);
286 return ret;
287 }
288
__netlink_deliver_tap(struct sk_buff * skb)289 static void __netlink_deliver_tap(struct sk_buff *skb)
290 {
291 int ret;
292 struct netlink_tap *tmp;
293
294 if (!netlink_filter_tap(skb))
295 return;
296
297 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
298 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
299 if (unlikely(ret))
300 break;
301 }
302 }
303
netlink_deliver_tap(struct sk_buff * skb)304 static void netlink_deliver_tap(struct sk_buff *skb)
305 {
306 rcu_read_lock();
307
308 if (unlikely(!list_empty(&netlink_tap_all)))
309 __netlink_deliver_tap(skb);
310
311 rcu_read_unlock();
312 }
313
netlink_deliver_tap_kernel(struct sock * dst,struct sock * src,struct sk_buff * skb)314 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
315 struct sk_buff *skb)
316 {
317 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
318 netlink_deliver_tap(skb);
319 }
320
netlink_overrun(struct sock * sk)321 static void netlink_overrun(struct sock *sk)
322 {
323 struct netlink_sock *nlk = nlk_sk(sk);
324
325 if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
326 if (!test_and_set_bit(NETLINK_S_CONGESTED,
327 &nlk_sk(sk)->state)) {
328 sk->sk_err = ENOBUFS;
329 sk->sk_error_report(sk);
330 }
331 }
332 atomic_inc(&sk->sk_drops);
333 }
334
netlink_rcv_wake(struct sock * sk)335 static void netlink_rcv_wake(struct sock *sk)
336 {
337 struct netlink_sock *nlk = nlk_sk(sk);
338
339 if (skb_queue_empty(&sk->sk_receive_queue))
340 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
341 if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
342 wake_up_interruptible(&nlk->wait);
343 }
344
netlink_skb_destructor(struct sk_buff * skb)345 static void netlink_skb_destructor(struct sk_buff *skb)
346 {
347 if (is_vmalloc_addr(skb->head)) {
348 if (!skb->cloned ||
349 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
350 vfree(skb->head);
351
352 skb->head = NULL;
353 }
354 if (skb->sk != NULL)
355 sock_rfree(skb);
356 }
357
netlink_skb_set_owner_r(struct sk_buff * skb,struct sock * sk)358 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
359 {
360 WARN_ON(skb->sk != NULL);
361 skb->sk = sk;
362 skb->destructor = netlink_skb_destructor;
363 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
364 sk_mem_charge(sk, skb->truesize);
365 }
366
netlink_sock_destruct(struct sock * sk)367 static void netlink_sock_destruct(struct sock *sk)
368 {
369 struct netlink_sock *nlk = nlk_sk(sk);
370
371 if (nlk->cb_running) {
372 if (nlk->cb.done)
373 nlk->cb.done(&nlk->cb);
374 module_put(nlk->cb.module);
375 kfree_skb(nlk->cb.skb);
376 }
377
378 skb_queue_purge(&sk->sk_receive_queue);
379
380 if (!sock_flag(sk, SOCK_DEAD)) {
381 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
382 return;
383 }
384
385 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
386 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
387 WARN_ON(nlk_sk(sk)->groups);
388 }
389
netlink_sock_destruct_work(struct work_struct * work)390 static void netlink_sock_destruct_work(struct work_struct *work)
391 {
392 struct netlink_sock *nlk = container_of(work, struct netlink_sock,
393 work);
394
395 sk_free(&nlk->sk);
396 }
397
398 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
399 * SMP. Look, when several writers sleep and reader wakes them up, all but one
400 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
401 * this, _but_ remember, it adds useless work on UP machines.
402 */
403
netlink_table_grab(void)404 void netlink_table_grab(void)
405 __acquires(nl_table_lock)
406 {
407 might_sleep();
408
409 write_lock_irq(&nl_table_lock);
410
411 if (atomic_read(&nl_table_users)) {
412 DECLARE_WAITQUEUE(wait, current);
413
414 add_wait_queue_exclusive(&nl_table_wait, &wait);
415 for (;;) {
416 set_current_state(TASK_UNINTERRUPTIBLE);
417 if (atomic_read(&nl_table_users) == 0)
418 break;
419 write_unlock_irq(&nl_table_lock);
420 schedule();
421 write_lock_irq(&nl_table_lock);
422 }
423
424 __set_current_state(TASK_RUNNING);
425 remove_wait_queue(&nl_table_wait, &wait);
426 }
427 }
428
netlink_table_ungrab(void)429 void netlink_table_ungrab(void)
430 __releases(nl_table_lock)
431 {
432 write_unlock_irq(&nl_table_lock);
433 wake_up(&nl_table_wait);
434 }
435
436 static inline void
netlink_lock_table(void)437 netlink_lock_table(void)
438 {
439 unsigned long flags;
440
441 /* read_lock() synchronizes us to netlink_table_grab */
442
443 read_lock_irqsave(&nl_table_lock, flags);
444 atomic_inc(&nl_table_users);
445 read_unlock_irqrestore(&nl_table_lock, flags);
446 }
447
448 static inline void
netlink_unlock_table(void)449 netlink_unlock_table(void)
450 {
451 if (atomic_dec_and_test(&nl_table_users))
452 wake_up(&nl_table_wait);
453 }
454
455 struct netlink_compare_arg
456 {
457 possible_net_t pnet;
458 u32 portid;
459 };
460
461 /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
462 #define netlink_compare_arg_len \
463 (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
464
netlink_compare(struct rhashtable_compare_arg * arg,const void * ptr)465 static inline int netlink_compare(struct rhashtable_compare_arg *arg,
466 const void *ptr)
467 {
468 const struct netlink_compare_arg *x = arg->key;
469 const struct netlink_sock *nlk = ptr;
470
471 return nlk->portid != x->portid ||
472 !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
473 }
474
netlink_compare_arg_init(struct netlink_compare_arg * arg,struct net * net,u32 portid)475 static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
476 struct net *net, u32 portid)
477 {
478 memset(arg, 0, sizeof(*arg));
479 write_pnet(&arg->pnet, net);
480 arg->portid = portid;
481 }
482
__netlink_lookup(struct netlink_table * table,u32 portid,struct net * net)483 static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
484 struct net *net)
485 {
486 struct netlink_compare_arg arg;
487
488 netlink_compare_arg_init(&arg, net, portid);
489 return rhashtable_lookup_fast(&table->hash, &arg,
490 netlink_rhashtable_params);
491 }
492
__netlink_insert(struct netlink_table * table,struct sock * sk)493 static int __netlink_insert(struct netlink_table *table, struct sock *sk)
494 {
495 struct netlink_compare_arg arg;
496
497 netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
498 return rhashtable_lookup_insert_key(&table->hash, &arg,
499 &nlk_sk(sk)->node,
500 netlink_rhashtable_params);
501 }
502
netlink_lookup(struct net * net,int protocol,u32 portid)503 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
504 {
505 struct netlink_table *table = &nl_table[protocol];
506 struct sock *sk;
507
508 rcu_read_lock();
509 sk = __netlink_lookup(table, portid, net);
510 if (sk)
511 sock_hold(sk);
512 rcu_read_unlock();
513
514 return sk;
515 }
516
517 static const struct proto_ops netlink_ops;
518
519 static void
netlink_update_listeners(struct sock * sk)520 netlink_update_listeners(struct sock *sk)
521 {
522 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
523 unsigned long mask;
524 unsigned int i;
525 struct listeners *listeners;
526
527 listeners = nl_deref_protected(tbl->listeners);
528 if (!listeners)
529 return;
530
531 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
532 mask = 0;
533 sk_for_each_bound(sk, &tbl->mc_list) {
534 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
535 mask |= nlk_sk(sk)->groups[i];
536 }
537 listeners->masks[i] = mask;
538 }
539 /* this function is only called with the netlink table "grabbed", which
540 * makes sure updates are visible before bind or setsockopt return. */
541 }
542
netlink_insert(struct sock * sk,u32 portid)543 static int netlink_insert(struct sock *sk, u32 portid)
544 {
545 struct netlink_table *table = &nl_table[sk->sk_protocol];
546 int err;
547
548 lock_sock(sk);
549
550 err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
551 if (nlk_sk(sk)->bound)
552 goto err;
553
554 err = -ENOMEM;
555 if (BITS_PER_LONG > 32 &&
556 unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))
557 goto err;
558
559 nlk_sk(sk)->portid = portid;
560 sock_hold(sk);
561
562 err = __netlink_insert(table, sk);
563 if (err) {
564 /* In case the hashtable backend returns with -EBUSY
565 * from here, it must not escape to the caller.
566 */
567 if (unlikely(err == -EBUSY))
568 err = -EOVERFLOW;
569 if (err == -EEXIST)
570 err = -EADDRINUSE;
571 sock_put(sk);
572 goto err;
573 }
574
575 /* We need to ensure that the socket is hashed and visible. */
576 smp_wmb();
577 /* Paired with lockless reads from netlink_bind(),
578 * netlink_connect() and netlink_sendmsg().
579 */
580 WRITE_ONCE(nlk_sk(sk)->bound, portid);
581
582 err:
583 release_sock(sk);
584 return err;
585 }
586
netlink_remove(struct sock * sk)587 static void netlink_remove(struct sock *sk)
588 {
589 struct netlink_table *table;
590
591 table = &nl_table[sk->sk_protocol];
592 if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
593 netlink_rhashtable_params)) {
594 WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
595 __sock_put(sk);
596 }
597
598 netlink_table_grab();
599 if (nlk_sk(sk)->subscriptions) {
600 __sk_del_bind_node(sk);
601 netlink_update_listeners(sk);
602 }
603 if (sk->sk_protocol == NETLINK_GENERIC)
604 atomic_inc(&genl_sk_destructing_cnt);
605 netlink_table_ungrab();
606 }
607
608 static struct proto netlink_proto = {
609 .name = "NETLINK",
610 .owner = THIS_MODULE,
611 .obj_size = sizeof(struct netlink_sock),
612 };
613
__netlink_create(struct net * net,struct socket * sock,struct mutex * cb_mutex,int protocol,int kern)614 static int __netlink_create(struct net *net, struct socket *sock,
615 struct mutex *cb_mutex, int protocol,
616 int kern)
617 {
618 struct sock *sk;
619 struct netlink_sock *nlk;
620
621 sock->ops = &netlink_ops;
622
623 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
624 if (!sk)
625 return -ENOMEM;
626
627 sock_init_data(sock, sk);
628
629 nlk = nlk_sk(sk);
630 if (cb_mutex) {
631 nlk->cb_mutex = cb_mutex;
632 } else {
633 nlk->cb_mutex = &nlk->cb_def_mutex;
634 mutex_init(nlk->cb_mutex);
635 lockdep_set_class_and_name(nlk->cb_mutex,
636 nlk_cb_mutex_keys + protocol,
637 nlk_cb_mutex_key_strings[protocol]);
638 }
639 init_waitqueue_head(&nlk->wait);
640
641 sk->sk_destruct = netlink_sock_destruct;
642 sk->sk_protocol = protocol;
643 return 0;
644 }
645
netlink_create(struct net * net,struct socket * sock,int protocol,int kern)646 static int netlink_create(struct net *net, struct socket *sock, int protocol,
647 int kern)
648 {
649 struct module *module = NULL;
650 struct mutex *cb_mutex;
651 struct netlink_sock *nlk;
652 int (*bind)(struct net *net, int group);
653 void (*unbind)(struct net *net, int group);
654 int err = 0;
655
656 sock->state = SS_UNCONNECTED;
657
658 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
659 return -ESOCKTNOSUPPORT;
660
661 if (protocol < 0 || protocol >= MAX_LINKS)
662 return -EPROTONOSUPPORT;
663 protocol = array_index_nospec(protocol, MAX_LINKS);
664
665 netlink_lock_table();
666 #ifdef CONFIG_MODULES
667 if (!nl_table[protocol].registered) {
668 netlink_unlock_table();
669 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
670 netlink_lock_table();
671 }
672 #endif
673 if (nl_table[protocol].registered &&
674 try_module_get(nl_table[protocol].module))
675 module = nl_table[protocol].module;
676 else
677 err = -EPROTONOSUPPORT;
678 cb_mutex = nl_table[protocol].cb_mutex;
679 bind = nl_table[protocol].bind;
680 unbind = nl_table[protocol].unbind;
681 netlink_unlock_table();
682
683 if (err < 0)
684 goto out;
685
686 err = __netlink_create(net, sock, cb_mutex, protocol, kern);
687 if (err < 0)
688 goto out_module;
689
690 local_bh_disable();
691 sock_prot_inuse_add(net, &netlink_proto, 1);
692 local_bh_enable();
693
694 nlk = nlk_sk(sock->sk);
695 nlk->module = module;
696 nlk->netlink_bind = bind;
697 nlk->netlink_unbind = unbind;
698 out:
699 return err;
700
701 out_module:
702 module_put(module);
703 goto out;
704 }
705
deferred_put_nlk_sk(struct rcu_head * head)706 static void deferred_put_nlk_sk(struct rcu_head *head)
707 {
708 struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
709 struct sock *sk = &nlk->sk;
710
711 if (!atomic_dec_and_test(&sk->sk_refcnt))
712 return;
713
714 if (nlk->cb_running && nlk->cb.done) {
715 INIT_WORK(&nlk->work, netlink_sock_destruct_work);
716 schedule_work(&nlk->work);
717 return;
718 }
719
720 sk_free(sk);
721 }
722
netlink_release(struct socket * sock)723 static int netlink_release(struct socket *sock)
724 {
725 struct sock *sk = sock->sk;
726 struct netlink_sock *nlk;
727
728 if (!sk)
729 return 0;
730
731 netlink_remove(sk);
732 sock_orphan(sk);
733 nlk = nlk_sk(sk);
734
735 /*
736 * OK. Socket is unlinked, any packets that arrive now
737 * will be purged.
738 */
739
740 /* must not acquire netlink_table_lock in any way again before unbind
741 * and notifying genetlink is done as otherwise it might deadlock
742 */
743 if (nlk->netlink_unbind) {
744 int i;
745
746 for (i = 0; i < nlk->ngroups; i++)
747 if (test_bit(i, nlk->groups))
748 nlk->netlink_unbind(sock_net(sk), i + 1);
749 }
750 if (sk->sk_protocol == NETLINK_GENERIC &&
751 atomic_dec_return(&genl_sk_destructing_cnt) == 0)
752 wake_up(&genl_sk_destructing_waitq);
753
754 sock->sk = NULL;
755 wake_up_interruptible_all(&nlk->wait);
756
757 skb_queue_purge(&sk->sk_write_queue);
758
759 if (nlk->portid && nlk->bound) {
760 struct netlink_notify n = {
761 .net = sock_net(sk),
762 .protocol = sk->sk_protocol,
763 .portid = nlk->portid,
764 };
765 atomic_notifier_call_chain(&netlink_chain,
766 NETLINK_URELEASE, &n);
767 }
768
769 module_put(nlk->module);
770
771 if (netlink_is_kernel(sk)) {
772 netlink_table_grab();
773 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
774 if (--nl_table[sk->sk_protocol].registered == 0) {
775 struct listeners *old;
776
777 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
778 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
779 kfree_rcu(old, rcu);
780 nl_table[sk->sk_protocol].module = NULL;
781 nl_table[sk->sk_protocol].bind = NULL;
782 nl_table[sk->sk_protocol].unbind = NULL;
783 nl_table[sk->sk_protocol].flags = 0;
784 nl_table[sk->sk_protocol].registered = 0;
785 }
786 netlink_table_ungrab();
787 }
788
789 kfree(nlk->groups);
790 nlk->groups = NULL;
791
792 local_bh_disable();
793 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
794 local_bh_enable();
795 call_rcu(&nlk->rcu, deferred_put_nlk_sk);
796 return 0;
797 }
798
netlink_autobind(struct socket * sock)799 static int netlink_autobind(struct socket *sock)
800 {
801 struct sock *sk = sock->sk;
802 struct net *net = sock_net(sk);
803 struct netlink_table *table = &nl_table[sk->sk_protocol];
804 s32 portid = task_tgid_vnr(current);
805 int err;
806 s32 rover = -4096;
807 bool ok;
808
809 retry:
810 cond_resched();
811 rcu_read_lock();
812 ok = !__netlink_lookup(table, portid, net);
813 rcu_read_unlock();
814 if (!ok) {
815 /* Bind collision, search negative portid values. */
816 if (rover == -4096)
817 /* rover will be in range [S32_MIN, -4097] */
818 rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
819 else if (rover >= -4096)
820 rover = -4097;
821 portid = rover--;
822 goto retry;
823 }
824
825 err = netlink_insert(sk, portid);
826 if (err == -EADDRINUSE)
827 goto retry;
828
829 /* If 2 threads race to autobind, that is fine. */
830 if (err == -EBUSY)
831 err = 0;
832
833 return err;
834 }
835
836 /**
837 * __netlink_ns_capable - General netlink message capability test
838 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
839 * @user_ns: The user namespace of the capability to use
840 * @cap: The capability to use
841 *
842 * Test to see if the opener of the socket we received the message
843 * from had when the netlink socket was created and the sender of the
844 * message has has the capability @cap in the user namespace @user_ns.
845 */
__netlink_ns_capable(const struct netlink_skb_parms * nsp,struct user_namespace * user_ns,int cap)846 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
847 struct user_namespace *user_ns, int cap)
848 {
849 return ((nsp->flags & NETLINK_SKB_DST) ||
850 file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
851 ns_capable(user_ns, cap);
852 }
853 EXPORT_SYMBOL(__netlink_ns_capable);
854
855 /**
856 * netlink_ns_capable - General netlink message capability test
857 * @skb: socket buffer holding a netlink command from userspace
858 * @user_ns: The user namespace of the capability to use
859 * @cap: The capability to use
860 *
861 * Test to see if the opener of the socket we received the message
862 * from had when the netlink socket was created and the sender of the
863 * message has has the capability @cap in the user namespace @user_ns.
864 */
netlink_ns_capable(const struct sk_buff * skb,struct user_namespace * user_ns,int cap)865 bool netlink_ns_capable(const struct sk_buff *skb,
866 struct user_namespace *user_ns, int cap)
867 {
868 return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
869 }
870 EXPORT_SYMBOL(netlink_ns_capable);
871
872 /**
873 * netlink_capable - Netlink global 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 in all user namespaces.
880 */
netlink_capable(const struct sk_buff * skb,int cap)881 bool netlink_capable(const struct sk_buff *skb, int cap)
882 {
883 return netlink_ns_capable(skb, &init_user_ns, cap);
884 }
885 EXPORT_SYMBOL(netlink_capable);
886
887 /**
888 * netlink_net_capable - Netlink network namespace message capability test
889 * @skb: socket buffer holding a netlink command from userspace
890 * @cap: The capability to use
891 *
892 * Test to see if the opener of the socket we received the message
893 * from had when the netlink socket was created and the sender of the
894 * message has has the capability @cap over the network namespace of
895 * the socket we received the message from.
896 */
netlink_net_capable(const struct sk_buff * skb,int cap)897 bool netlink_net_capable(const struct sk_buff *skb, int cap)
898 {
899 return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
900 }
901 EXPORT_SYMBOL(netlink_net_capable);
902
netlink_allowed(const struct socket * sock,unsigned int flag)903 static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
904 {
905 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
906 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
907 }
908
909 static void
netlink_update_subscriptions(struct sock * sk,unsigned int subscriptions)910 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
911 {
912 struct netlink_sock *nlk = nlk_sk(sk);
913
914 if (nlk->subscriptions && !subscriptions)
915 __sk_del_bind_node(sk);
916 else if (!nlk->subscriptions && subscriptions)
917 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
918 nlk->subscriptions = subscriptions;
919 }
920
netlink_realloc_groups(struct sock * sk)921 static int netlink_realloc_groups(struct sock *sk)
922 {
923 struct netlink_sock *nlk = nlk_sk(sk);
924 unsigned int groups;
925 unsigned long *new_groups;
926 int err = 0;
927
928 netlink_table_grab();
929
930 groups = nl_table[sk->sk_protocol].groups;
931 if (!nl_table[sk->sk_protocol].registered) {
932 err = -ENOENT;
933 goto out_unlock;
934 }
935
936 if (nlk->ngroups >= groups)
937 goto out_unlock;
938
939 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
940 if (new_groups == NULL) {
941 err = -ENOMEM;
942 goto out_unlock;
943 }
944 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
945 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
946
947 nlk->groups = new_groups;
948 nlk->ngroups = groups;
949 out_unlock:
950 netlink_table_ungrab();
951 return err;
952 }
953
netlink_undo_bind(int group,long unsigned int groups,struct sock * sk)954 static void netlink_undo_bind(int group, long unsigned int groups,
955 struct sock *sk)
956 {
957 struct netlink_sock *nlk = nlk_sk(sk);
958 int undo;
959
960 if (!nlk->netlink_unbind)
961 return;
962
963 for (undo = 0; undo < group; undo++)
964 if (test_bit(undo, &groups))
965 nlk->netlink_unbind(sock_net(sk), undo + 1);
966 }
967
netlink_bind(struct socket * sock,struct sockaddr * addr,int addr_len)968 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
969 int addr_len)
970 {
971 struct sock *sk = sock->sk;
972 struct net *net = sock_net(sk);
973 struct netlink_sock *nlk = nlk_sk(sk);
974 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
975 int err;
976 long unsigned int groups = nladdr->nl_groups;
977 bool bound;
978
979 if (addr_len < sizeof(struct sockaddr_nl))
980 return -EINVAL;
981
982 if (nladdr->nl_family != AF_NETLINK)
983 return -EINVAL;
984
985 /* Only superuser is allowed to listen multicasts */
986 if (groups) {
987 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
988 return -EPERM;
989 err = netlink_realloc_groups(sk);
990 if (err)
991 return err;
992 }
993
994 if (nlk->ngroups == 0)
995 groups = 0;
996 else if (nlk->ngroups < 8*sizeof(groups))
997 groups &= (1UL << nlk->ngroups) - 1;
998
999 /* Paired with WRITE_ONCE() in netlink_insert() */
1000 bound = READ_ONCE(nlk->bound);
1001 if (bound) {
1002 /* Ensure nlk->portid is up-to-date. */
1003 smp_rmb();
1004
1005 if (nladdr->nl_pid != nlk->portid)
1006 return -EINVAL;
1007 }
1008
1009 if (nlk->netlink_bind && groups) {
1010 int group;
1011
1012 /* nl_groups is a u32, so cap the maximum groups we can bind */
1013 for (group = 0; group < BITS_PER_TYPE(u32); group++) {
1014 if (!test_bit(group, &groups))
1015 continue;
1016 err = nlk->netlink_bind(net, group + 1);
1017 if (!err)
1018 continue;
1019 netlink_undo_bind(group, groups, sk);
1020 return err;
1021 }
1022 }
1023
1024 /* No need for barriers here as we return to user-space without
1025 * using any of the bound attributes.
1026 */
1027 if (!bound) {
1028 err = nladdr->nl_pid ?
1029 netlink_insert(sk, nladdr->nl_pid) :
1030 netlink_autobind(sock);
1031 if (err) {
1032 netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk);
1033 return err;
1034 }
1035 }
1036
1037 if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1038 return 0;
1039
1040 netlink_table_grab();
1041 netlink_update_subscriptions(sk, nlk->subscriptions +
1042 hweight32(groups) -
1043 hweight32(nlk->groups[0]));
1044 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
1045 netlink_update_listeners(sk);
1046 netlink_table_ungrab();
1047
1048 return 0;
1049 }
1050
netlink_connect(struct socket * sock,struct sockaddr * addr,int alen,int flags)1051 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1052 int alen, int flags)
1053 {
1054 int err = 0;
1055 struct sock *sk = sock->sk;
1056 struct netlink_sock *nlk = nlk_sk(sk);
1057 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1058
1059 if (alen < sizeof(addr->sa_family))
1060 return -EINVAL;
1061
1062 if (addr->sa_family == AF_UNSPEC) {
1063 sk->sk_state = NETLINK_UNCONNECTED;
1064 nlk->dst_portid = 0;
1065 nlk->dst_group = 0;
1066 return 0;
1067 }
1068 if (addr->sa_family != AF_NETLINK)
1069 return -EINVAL;
1070
1071 if (alen < sizeof(struct sockaddr_nl))
1072 return -EINVAL;
1073
1074 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1075 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1076 return -EPERM;
1077
1078 /* No need for barriers here as we return to user-space without
1079 * using any of the bound attributes.
1080 * Paired with WRITE_ONCE() in netlink_insert().
1081 */
1082 if (!READ_ONCE(nlk->bound))
1083 err = netlink_autobind(sock);
1084
1085 if (err == 0) {
1086 sk->sk_state = NETLINK_CONNECTED;
1087 nlk->dst_portid = nladdr->nl_pid;
1088 nlk->dst_group = ffs(nladdr->nl_groups);
1089 }
1090
1091 return err;
1092 }
1093
netlink_getname(struct socket * sock,struct sockaddr * addr,int * addr_len,int peer)1094 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1095 int *addr_len, int peer)
1096 {
1097 struct sock *sk = sock->sk;
1098 struct netlink_sock *nlk = nlk_sk(sk);
1099 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1100
1101 nladdr->nl_family = AF_NETLINK;
1102 nladdr->nl_pad = 0;
1103 *addr_len = sizeof(*nladdr);
1104
1105 if (peer) {
1106 nladdr->nl_pid = nlk->dst_portid;
1107 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1108 } else {
1109 nladdr->nl_pid = nlk->portid;
1110 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1111 }
1112 return 0;
1113 }
1114
netlink_getsockbyportid(struct sock * ssk,u32 portid)1115 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1116 {
1117 struct sock *sock;
1118 struct netlink_sock *nlk;
1119
1120 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1121 if (!sock)
1122 return ERR_PTR(-ECONNREFUSED);
1123
1124 /* Don't bother queuing skb if kernel socket has no input function */
1125 nlk = nlk_sk(sock);
1126 if (sock->sk_state == NETLINK_CONNECTED &&
1127 nlk->dst_portid != nlk_sk(ssk)->portid) {
1128 sock_put(sock);
1129 return ERR_PTR(-ECONNREFUSED);
1130 }
1131 return sock;
1132 }
1133
netlink_getsockbyfilp(struct file * filp)1134 struct sock *netlink_getsockbyfilp(struct file *filp)
1135 {
1136 struct inode *inode = file_inode(filp);
1137 struct sock *sock;
1138
1139 if (!S_ISSOCK(inode->i_mode))
1140 return ERR_PTR(-ENOTSOCK);
1141
1142 sock = SOCKET_I(inode)->sk;
1143 if (sock->sk_family != AF_NETLINK)
1144 return ERR_PTR(-EINVAL);
1145
1146 sock_hold(sock);
1147 return sock;
1148 }
1149
netlink_alloc_large_skb(unsigned int size,int broadcast)1150 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1151 int broadcast)
1152 {
1153 struct sk_buff *skb;
1154 void *data;
1155
1156 if (size <= NLMSG_GOODSIZE || broadcast)
1157 return alloc_skb(size, GFP_KERNEL);
1158
1159 size = SKB_DATA_ALIGN(size) +
1160 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1161
1162 data = vmalloc(size);
1163 if (data == NULL)
1164 return NULL;
1165
1166 skb = __build_skb(data, size);
1167 if (skb == NULL)
1168 vfree(data);
1169 else
1170 skb->destructor = netlink_skb_destructor;
1171
1172 return skb;
1173 }
1174
1175 /*
1176 * Attach a skb to a netlink socket.
1177 * The caller must hold a reference to the destination socket. On error, the
1178 * reference is dropped. The skb is not send to the destination, just all
1179 * all error checks are performed and memory in the queue is reserved.
1180 * Return values:
1181 * < 0: error. skb freed, reference to sock dropped.
1182 * 0: continue
1183 * 1: repeat lookup - reference dropped while waiting for socket memory.
1184 */
netlink_attachskb(struct sock * sk,struct sk_buff * skb,long * timeo,struct sock * ssk)1185 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1186 long *timeo, struct sock *ssk)
1187 {
1188 struct netlink_sock *nlk;
1189
1190 nlk = nlk_sk(sk);
1191
1192 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1193 test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
1194 DECLARE_WAITQUEUE(wait, current);
1195 if (!*timeo) {
1196 if (!ssk || netlink_is_kernel(ssk))
1197 netlink_overrun(sk);
1198 sock_put(sk);
1199 kfree_skb(skb);
1200 return -EAGAIN;
1201 }
1202
1203 __set_current_state(TASK_INTERRUPTIBLE);
1204 add_wait_queue(&nlk->wait, &wait);
1205
1206 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1207 test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
1208 !sock_flag(sk, SOCK_DEAD))
1209 *timeo = schedule_timeout(*timeo);
1210
1211 __set_current_state(TASK_RUNNING);
1212 remove_wait_queue(&nlk->wait, &wait);
1213 sock_put(sk);
1214
1215 if (signal_pending(current)) {
1216 kfree_skb(skb);
1217 return sock_intr_errno(*timeo);
1218 }
1219 return 1;
1220 }
1221 netlink_skb_set_owner_r(skb, sk);
1222 return 0;
1223 }
1224
__netlink_sendskb(struct sock * sk,struct sk_buff * skb)1225 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1226 {
1227 int len = skb->len;
1228
1229 netlink_deliver_tap(skb);
1230
1231 skb_queue_tail(&sk->sk_receive_queue, skb);
1232 sk->sk_data_ready(sk);
1233 return len;
1234 }
1235
netlink_sendskb(struct sock * sk,struct sk_buff * skb)1236 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1237 {
1238 int len = __netlink_sendskb(sk, skb);
1239
1240 sock_put(sk);
1241 return len;
1242 }
1243
netlink_detachskb(struct sock * sk,struct sk_buff * skb)1244 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1245 {
1246 kfree_skb(skb);
1247 sock_put(sk);
1248 }
1249
netlink_trim(struct sk_buff * skb,gfp_t allocation)1250 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1251 {
1252 int delta;
1253
1254 WARN_ON(skb->sk != NULL);
1255 delta = skb->end - skb->tail;
1256 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1257 return skb;
1258
1259 if (skb_shared(skb)) {
1260 struct sk_buff *nskb = skb_clone(skb, allocation);
1261 if (!nskb)
1262 return skb;
1263 consume_skb(skb);
1264 skb = nskb;
1265 }
1266
1267 if (!pskb_expand_head(skb, 0, -delta, allocation))
1268 skb->truesize -= delta;
1269
1270 return skb;
1271 }
1272
netlink_unicast_kernel(struct sock * sk,struct sk_buff * skb,struct sock * ssk)1273 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1274 struct sock *ssk)
1275 {
1276 int ret;
1277 struct netlink_sock *nlk = nlk_sk(sk);
1278
1279 ret = -ECONNREFUSED;
1280 if (nlk->netlink_rcv != NULL) {
1281 ret = skb->len;
1282 netlink_skb_set_owner_r(skb, sk);
1283 NETLINK_CB(skb).sk = ssk;
1284 netlink_deliver_tap_kernel(sk, ssk, skb);
1285 nlk->netlink_rcv(skb);
1286 consume_skb(skb);
1287 } else {
1288 kfree_skb(skb);
1289 }
1290 sock_put(sk);
1291 return ret;
1292 }
1293
netlink_unicast(struct sock * ssk,struct sk_buff * skb,u32 portid,int nonblock)1294 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1295 u32 portid, int nonblock)
1296 {
1297 struct sock *sk;
1298 int err;
1299 long timeo;
1300
1301 skb = netlink_trim(skb, gfp_any());
1302
1303 timeo = sock_sndtimeo(ssk, nonblock);
1304 retry:
1305 sk = netlink_getsockbyportid(ssk, portid);
1306 if (IS_ERR(sk)) {
1307 kfree_skb(skb);
1308 return PTR_ERR(sk);
1309 }
1310 if (netlink_is_kernel(sk))
1311 return netlink_unicast_kernel(sk, skb, ssk);
1312
1313 if (sk_filter(sk, skb)) {
1314 err = skb->len;
1315 kfree_skb(skb);
1316 sock_put(sk);
1317 return err;
1318 }
1319
1320 err = netlink_attachskb(sk, skb, &timeo, ssk);
1321 if (err == 1)
1322 goto retry;
1323 if (err)
1324 return err;
1325
1326 return netlink_sendskb(sk, skb);
1327 }
1328 EXPORT_SYMBOL(netlink_unicast);
1329
__netlink_alloc_skb(struct sock * ssk,unsigned int size,unsigned int ldiff,u32 dst_portid,gfp_t gfp_mask)1330 struct sk_buff *__netlink_alloc_skb(struct sock *ssk, unsigned int size,
1331 unsigned int ldiff, u32 dst_portid,
1332 gfp_t gfp_mask)
1333 {
1334 return alloc_skb(size, gfp_mask);
1335 }
1336 EXPORT_SYMBOL_GPL(__netlink_alloc_skb);
1337
netlink_has_listeners(struct sock * sk,unsigned int group)1338 int netlink_has_listeners(struct sock *sk, unsigned int group)
1339 {
1340 int res = 0;
1341 struct listeners *listeners;
1342
1343 BUG_ON(!netlink_is_kernel(sk));
1344
1345 rcu_read_lock();
1346 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1347
1348 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1349 res = test_bit(group - 1, listeners->masks);
1350
1351 rcu_read_unlock();
1352
1353 return res;
1354 }
1355 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1356
netlink_broadcast_deliver(struct sock * sk,struct sk_buff * skb)1357 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1358 {
1359 struct netlink_sock *nlk = nlk_sk(sk);
1360
1361 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1362 !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
1363 netlink_skb_set_owner_r(skb, sk);
1364 __netlink_sendskb(sk, skb);
1365 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1366 }
1367 return -1;
1368 }
1369
1370 struct netlink_broadcast_data {
1371 struct sock *exclude_sk;
1372 struct net *net;
1373 u32 portid;
1374 u32 group;
1375 int failure;
1376 int delivery_failure;
1377 int congested;
1378 int delivered;
1379 gfp_t allocation;
1380 struct sk_buff *skb, *skb2;
1381 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1382 void *tx_data;
1383 };
1384
do_one_broadcast(struct sock * sk,struct netlink_broadcast_data * p)1385 static void do_one_broadcast(struct sock *sk,
1386 struct netlink_broadcast_data *p)
1387 {
1388 struct netlink_sock *nlk = nlk_sk(sk);
1389 int val;
1390
1391 if (p->exclude_sk == sk)
1392 return;
1393
1394 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1395 !test_bit(p->group - 1, nlk->groups))
1396 return;
1397
1398 if (!net_eq(sock_net(sk), p->net)) {
1399 if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
1400 return;
1401
1402 if (!peernet_has_id(sock_net(sk), p->net))
1403 return;
1404
1405 if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
1406 CAP_NET_BROADCAST))
1407 return;
1408 }
1409
1410 if (p->failure) {
1411 netlink_overrun(sk);
1412 return;
1413 }
1414
1415 sock_hold(sk);
1416 if (p->skb2 == NULL) {
1417 if (skb_shared(p->skb)) {
1418 p->skb2 = skb_clone(p->skb, p->allocation);
1419 } else {
1420 p->skb2 = skb_get(p->skb);
1421 /*
1422 * skb ownership may have been set when
1423 * delivered to a previous socket.
1424 */
1425 skb_orphan(p->skb2);
1426 }
1427 }
1428 if (p->skb2 == NULL) {
1429 netlink_overrun(sk);
1430 /* Clone failed. Notify ALL listeners. */
1431 p->failure = 1;
1432 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1433 p->delivery_failure = 1;
1434 goto out;
1435 }
1436 if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1437 kfree_skb(p->skb2);
1438 p->skb2 = NULL;
1439 goto out;
1440 }
1441 if (sk_filter(sk, p->skb2)) {
1442 kfree_skb(p->skb2);
1443 p->skb2 = NULL;
1444 goto out;
1445 }
1446 NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
1447 NETLINK_CB(p->skb2).nsid_is_set = true;
1448 val = netlink_broadcast_deliver(sk, p->skb2);
1449 if (val < 0) {
1450 netlink_overrun(sk);
1451 if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
1452 p->delivery_failure = 1;
1453 } else {
1454 p->congested |= val;
1455 p->delivered = 1;
1456 p->skb2 = NULL;
1457 }
1458 out:
1459 sock_put(sk);
1460 }
1461
netlink_broadcast_filtered(struct sock * ssk,struct sk_buff * skb,u32 portid,u32 group,gfp_t allocation,int (* filter)(struct sock * dsk,struct sk_buff * skb,void * data),void * filter_data)1462 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1463 u32 group, gfp_t allocation,
1464 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1465 void *filter_data)
1466 {
1467 struct net *net = sock_net(ssk);
1468 struct netlink_broadcast_data info;
1469 struct sock *sk;
1470
1471 skb = netlink_trim(skb, allocation);
1472
1473 info.exclude_sk = ssk;
1474 info.net = net;
1475 info.portid = portid;
1476 info.group = group;
1477 info.failure = 0;
1478 info.delivery_failure = 0;
1479 info.congested = 0;
1480 info.delivered = 0;
1481 info.allocation = allocation;
1482 info.skb = skb;
1483 info.skb2 = NULL;
1484 info.tx_filter = filter;
1485 info.tx_data = filter_data;
1486
1487 /* While we sleep in clone, do not allow to change socket list */
1488
1489 netlink_lock_table();
1490
1491 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1492 do_one_broadcast(sk, &info);
1493
1494 consume_skb(skb);
1495
1496 netlink_unlock_table();
1497
1498 if (info.delivery_failure) {
1499 kfree_skb(info.skb2);
1500 return -ENOBUFS;
1501 }
1502 consume_skb(info.skb2);
1503
1504 if (info.delivered) {
1505 if (info.congested && gfpflags_allow_blocking(allocation))
1506 yield();
1507 return 0;
1508 }
1509 return -ESRCH;
1510 }
1511 EXPORT_SYMBOL(netlink_broadcast_filtered);
1512
netlink_broadcast(struct sock * ssk,struct sk_buff * skb,u32 portid,u32 group,gfp_t allocation)1513 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1514 u32 group, gfp_t allocation)
1515 {
1516 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1517 NULL, NULL);
1518 }
1519 EXPORT_SYMBOL(netlink_broadcast);
1520
1521 struct netlink_set_err_data {
1522 struct sock *exclude_sk;
1523 u32 portid;
1524 u32 group;
1525 int code;
1526 };
1527
do_one_set_err(struct sock * sk,struct netlink_set_err_data * p)1528 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1529 {
1530 struct netlink_sock *nlk = nlk_sk(sk);
1531 int ret = 0;
1532
1533 if (sk == p->exclude_sk)
1534 goto out;
1535
1536 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1537 goto out;
1538
1539 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1540 !test_bit(p->group - 1, nlk->groups))
1541 goto out;
1542
1543 if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
1544 ret = 1;
1545 goto out;
1546 }
1547
1548 sk->sk_err = p->code;
1549 sk->sk_error_report(sk);
1550 out:
1551 return ret;
1552 }
1553
1554 /**
1555 * netlink_set_err - report error to broadcast listeners
1556 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1557 * @portid: the PORTID of a process that we want to skip (if any)
1558 * @group: the broadcast group that will notice the error
1559 * @code: error code, must be negative (as usual in kernelspace)
1560 *
1561 * This function returns the number of broadcast listeners that have set the
1562 * NETLINK_NO_ENOBUFS socket option.
1563 */
netlink_set_err(struct sock * ssk,u32 portid,u32 group,int code)1564 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1565 {
1566 struct netlink_set_err_data info;
1567 struct sock *sk;
1568 int ret = 0;
1569
1570 info.exclude_sk = ssk;
1571 info.portid = portid;
1572 info.group = group;
1573 /* sk->sk_err wants a positive error value */
1574 info.code = -code;
1575
1576 read_lock(&nl_table_lock);
1577
1578 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1579 ret += do_one_set_err(sk, &info);
1580
1581 read_unlock(&nl_table_lock);
1582 return ret;
1583 }
1584 EXPORT_SYMBOL(netlink_set_err);
1585
1586 /* must be called with netlink table grabbed */
netlink_update_socket_mc(struct netlink_sock * nlk,unsigned int group,int is_new)1587 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1588 unsigned int group,
1589 int is_new)
1590 {
1591 int old, new = !!is_new, subscriptions;
1592
1593 old = test_bit(group - 1, nlk->groups);
1594 subscriptions = nlk->subscriptions - old + new;
1595 if (new)
1596 __set_bit(group - 1, nlk->groups);
1597 else
1598 __clear_bit(group - 1, nlk->groups);
1599 netlink_update_subscriptions(&nlk->sk, subscriptions);
1600 netlink_update_listeners(&nlk->sk);
1601 }
1602
netlink_setsockopt(struct socket * sock,int level,int optname,char __user * optval,unsigned int optlen)1603 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1604 char __user *optval, unsigned int optlen)
1605 {
1606 struct sock *sk = sock->sk;
1607 struct netlink_sock *nlk = nlk_sk(sk);
1608 unsigned int val = 0;
1609 int err;
1610
1611 if (level != SOL_NETLINK)
1612 return -ENOPROTOOPT;
1613
1614 if (optlen >= sizeof(int) &&
1615 get_user(val, (unsigned int __user *)optval))
1616 return -EFAULT;
1617
1618 switch (optname) {
1619 case NETLINK_PKTINFO:
1620 if (val)
1621 nlk->flags |= NETLINK_F_RECV_PKTINFO;
1622 else
1623 nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
1624 err = 0;
1625 break;
1626 case NETLINK_ADD_MEMBERSHIP:
1627 case NETLINK_DROP_MEMBERSHIP: {
1628 if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
1629 return -EPERM;
1630 err = netlink_realloc_groups(sk);
1631 if (err)
1632 return err;
1633 if (!val || val - 1 >= nlk->ngroups)
1634 return -EINVAL;
1635 if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
1636 err = nlk->netlink_bind(sock_net(sk), val);
1637 if (err)
1638 return err;
1639 }
1640 netlink_table_grab();
1641 netlink_update_socket_mc(nlk, val,
1642 optname == NETLINK_ADD_MEMBERSHIP);
1643 netlink_table_ungrab();
1644 if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
1645 nlk->netlink_unbind(sock_net(sk), val);
1646
1647 err = 0;
1648 break;
1649 }
1650 case NETLINK_BROADCAST_ERROR:
1651 if (val)
1652 nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
1653 else
1654 nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
1655 err = 0;
1656 break;
1657 case NETLINK_NO_ENOBUFS:
1658 if (val) {
1659 nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
1660 clear_bit(NETLINK_S_CONGESTED, &nlk->state);
1661 wake_up_interruptible(&nlk->wait);
1662 } else {
1663 nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
1664 }
1665 err = 0;
1666 break;
1667 case NETLINK_LISTEN_ALL_NSID:
1668 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
1669 return -EPERM;
1670
1671 if (val)
1672 nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
1673 else
1674 nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
1675 err = 0;
1676 break;
1677 case NETLINK_CAP_ACK:
1678 if (val)
1679 nlk->flags |= NETLINK_F_CAP_ACK;
1680 else
1681 nlk->flags &= ~NETLINK_F_CAP_ACK;
1682 err = 0;
1683 break;
1684 default:
1685 err = -ENOPROTOOPT;
1686 }
1687 return err;
1688 }
1689
netlink_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1690 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1691 char __user *optval, int __user *optlen)
1692 {
1693 struct sock *sk = sock->sk;
1694 struct netlink_sock *nlk = nlk_sk(sk);
1695 int len, val, err;
1696
1697 if (level != SOL_NETLINK)
1698 return -ENOPROTOOPT;
1699
1700 if (get_user(len, optlen))
1701 return -EFAULT;
1702 if (len < 0)
1703 return -EINVAL;
1704
1705 switch (optname) {
1706 case NETLINK_PKTINFO:
1707 if (len < sizeof(int))
1708 return -EINVAL;
1709 len = sizeof(int);
1710 val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
1711 if (put_user(len, optlen) ||
1712 put_user(val, optval))
1713 return -EFAULT;
1714 err = 0;
1715 break;
1716 case NETLINK_BROADCAST_ERROR:
1717 if (len < sizeof(int))
1718 return -EINVAL;
1719 len = sizeof(int);
1720 val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
1721 if (put_user(len, optlen) ||
1722 put_user(val, optval))
1723 return -EFAULT;
1724 err = 0;
1725 break;
1726 case NETLINK_NO_ENOBUFS:
1727 if (len < sizeof(int))
1728 return -EINVAL;
1729 len = sizeof(int);
1730 val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
1731 if (put_user(len, optlen) ||
1732 put_user(val, optval))
1733 return -EFAULT;
1734 err = 0;
1735 break;
1736 case NETLINK_LIST_MEMBERSHIPS: {
1737 int pos, idx, shift;
1738
1739 err = 0;
1740 netlink_lock_table();
1741 for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
1742 if (len - pos < sizeof(u32))
1743 break;
1744
1745 idx = pos / sizeof(unsigned long);
1746 shift = (pos % sizeof(unsigned long)) * 8;
1747 if (put_user((u32)(nlk->groups[idx] >> shift),
1748 (u32 __user *)(optval + pos))) {
1749 err = -EFAULT;
1750 break;
1751 }
1752 }
1753 if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
1754 err = -EFAULT;
1755 netlink_unlock_table();
1756 break;
1757 }
1758 case NETLINK_CAP_ACK:
1759 if (len < sizeof(int))
1760 return -EINVAL;
1761 len = sizeof(int);
1762 val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
1763 if (put_user(len, optlen) ||
1764 put_user(val, optval))
1765 return -EFAULT;
1766 err = 0;
1767 break;
1768 default:
1769 err = -ENOPROTOOPT;
1770 }
1771 return err;
1772 }
1773
netlink_cmsg_recv_pktinfo(struct msghdr * msg,struct sk_buff * skb)1774 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1775 {
1776 struct nl_pktinfo info;
1777
1778 info.group = NETLINK_CB(skb).dst_group;
1779 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1780 }
1781
netlink_cmsg_listen_all_nsid(struct sock * sk,struct msghdr * msg,struct sk_buff * skb)1782 static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
1783 struct sk_buff *skb)
1784 {
1785 if (!NETLINK_CB(skb).nsid_is_set)
1786 return;
1787
1788 put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
1789 &NETLINK_CB(skb).nsid);
1790 }
1791
netlink_sendmsg(struct socket * sock,struct msghdr * msg,size_t len)1792 static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1793 {
1794 struct sock *sk = sock->sk;
1795 struct netlink_sock *nlk = nlk_sk(sk);
1796 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1797 u32 dst_portid;
1798 u32 dst_group;
1799 struct sk_buff *skb;
1800 int err;
1801 struct scm_cookie scm;
1802 u32 netlink_skb_flags = 0;
1803
1804 if (msg->msg_flags&MSG_OOB)
1805 return -EOPNOTSUPP;
1806
1807 if (len == 0) {
1808 pr_warn_once("Zero length message leads to an empty skb\n");
1809 return -ENODATA;
1810 }
1811
1812 err = scm_send(sock, msg, &scm, true);
1813 if (err < 0)
1814 return err;
1815
1816 if (msg->msg_namelen) {
1817 err = -EINVAL;
1818 if (msg->msg_namelen < sizeof(struct sockaddr_nl))
1819 goto out;
1820 if (addr->nl_family != AF_NETLINK)
1821 goto out;
1822 dst_portid = addr->nl_pid;
1823 dst_group = ffs(addr->nl_groups);
1824 err = -EPERM;
1825 if ((dst_group || dst_portid) &&
1826 !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
1827 goto out;
1828 netlink_skb_flags |= NETLINK_SKB_DST;
1829 } else {
1830 dst_portid = nlk->dst_portid;
1831 dst_group = nlk->dst_group;
1832 }
1833
1834 /* Paired with WRITE_ONCE() in netlink_insert() */
1835 if (!READ_ONCE(nlk->bound)) {
1836 err = netlink_autobind(sock);
1837 if (err)
1838 goto out;
1839 } else {
1840 /* Ensure nlk is hashed and visible. */
1841 smp_rmb();
1842 }
1843
1844 err = -EMSGSIZE;
1845 if (len > sk->sk_sndbuf - 32)
1846 goto out;
1847 err = -ENOBUFS;
1848 skb = netlink_alloc_large_skb(len, dst_group);
1849 if (skb == NULL)
1850 goto out;
1851
1852 NETLINK_CB(skb).portid = nlk->portid;
1853 NETLINK_CB(skb).dst_group = dst_group;
1854 NETLINK_CB(skb).creds = scm.creds;
1855 NETLINK_CB(skb).flags = netlink_skb_flags;
1856
1857 err = -EFAULT;
1858 if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
1859 kfree_skb(skb);
1860 goto out;
1861 }
1862
1863 err = security_netlink_send(sk, skb);
1864 if (err) {
1865 kfree_skb(skb);
1866 goto out;
1867 }
1868
1869 if (dst_group) {
1870 atomic_inc(&skb->users);
1871 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1872 }
1873 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1874
1875 out:
1876 scm_destroy(&scm);
1877 return err;
1878 }
1879
netlink_recvmsg(struct socket * sock,struct msghdr * msg,size_t len,int flags)1880 static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
1881 int flags)
1882 {
1883 struct scm_cookie scm;
1884 struct sock *sk = sock->sk;
1885 struct netlink_sock *nlk = nlk_sk(sk);
1886 int noblock = flags&MSG_DONTWAIT;
1887 size_t copied;
1888 struct sk_buff *skb, *data_skb;
1889 int err, ret;
1890
1891 if (flags&MSG_OOB)
1892 return -EOPNOTSUPP;
1893
1894 copied = 0;
1895
1896 skb = skb_recv_datagram(sk, flags, noblock, &err);
1897 if (skb == NULL)
1898 goto out;
1899
1900 data_skb = skb;
1901
1902 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1903 if (unlikely(skb_shinfo(skb)->frag_list)) {
1904 /*
1905 * If this skb has a frag_list, then here that means that we
1906 * will have to use the frag_list skb's data for compat tasks
1907 * and the regular skb's data for normal (non-compat) tasks.
1908 *
1909 * If we need to send the compat skb, assign it to the
1910 * 'data_skb' variable so that it will be used below for data
1911 * copying. We keep 'skb' for everything else, including
1912 * freeing both later.
1913 */
1914 if (flags & MSG_CMSG_COMPAT)
1915 data_skb = skb_shinfo(skb)->frag_list;
1916 }
1917 #endif
1918
1919 /* Record the max length of recvmsg() calls for future allocations */
1920 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
1921 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
1922 SKB_WITH_OVERHEAD(32768));
1923
1924 copied = data_skb->len;
1925 if (len < copied) {
1926 msg->msg_flags |= MSG_TRUNC;
1927 copied = len;
1928 }
1929
1930 skb_reset_transport_header(data_skb);
1931 err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
1932
1933 if (msg->msg_name) {
1934 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
1935 addr->nl_family = AF_NETLINK;
1936 addr->nl_pad = 0;
1937 addr->nl_pid = NETLINK_CB(skb).portid;
1938 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1939 msg->msg_namelen = sizeof(*addr);
1940 }
1941
1942 if (nlk->flags & NETLINK_F_RECV_PKTINFO)
1943 netlink_cmsg_recv_pktinfo(msg, skb);
1944 if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
1945 netlink_cmsg_listen_all_nsid(sk, msg, skb);
1946
1947 memset(&scm, 0, sizeof(scm));
1948 scm.creds = *NETLINK_CREDS(skb);
1949 if (flags & MSG_TRUNC)
1950 copied = data_skb->len;
1951
1952 skb_free_datagram(sk, skb);
1953
1954 if (nlk->cb_running &&
1955 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1956 ret = netlink_dump(sk);
1957 if (ret) {
1958 sk->sk_err = -ret;
1959 sk->sk_error_report(sk);
1960 }
1961 }
1962
1963 scm_recv(sock, msg, &scm, flags);
1964 out:
1965 netlink_rcv_wake(sk);
1966 return err ? : copied;
1967 }
1968
netlink_data_ready(struct sock * sk)1969 static void netlink_data_ready(struct sock *sk)
1970 {
1971 BUG();
1972 }
1973
1974 /*
1975 * We export these functions to other modules. They provide a
1976 * complete set of kernel non-blocking support for message
1977 * queueing.
1978 */
1979
1980 struct sock *
__netlink_kernel_create(struct net * net,int unit,struct module * module,struct netlink_kernel_cfg * cfg)1981 __netlink_kernel_create(struct net *net, int unit, struct module *module,
1982 struct netlink_kernel_cfg *cfg)
1983 {
1984 struct socket *sock;
1985 struct sock *sk;
1986 struct netlink_sock *nlk;
1987 struct listeners *listeners = NULL;
1988 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
1989 unsigned int groups;
1990
1991 BUG_ON(!nl_table);
1992
1993 if (unit < 0 || unit >= MAX_LINKS)
1994 return NULL;
1995
1996 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1997 return NULL;
1998
1999 if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
2000 goto out_sock_release_nosk;
2001
2002 sk = sock->sk;
2003
2004 if (!cfg || cfg->groups < 32)
2005 groups = 32;
2006 else
2007 groups = cfg->groups;
2008
2009 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2010 if (!listeners)
2011 goto out_sock_release;
2012
2013 sk->sk_data_ready = netlink_data_ready;
2014 if (cfg && cfg->input)
2015 nlk_sk(sk)->netlink_rcv = cfg->input;
2016
2017 if (netlink_insert(sk, 0))
2018 goto out_sock_release;
2019
2020 nlk = nlk_sk(sk);
2021 nlk->flags |= NETLINK_F_KERNEL_SOCKET;
2022
2023 netlink_table_grab();
2024 if (!nl_table[unit].registered) {
2025 nl_table[unit].groups = groups;
2026 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2027 nl_table[unit].cb_mutex = cb_mutex;
2028 nl_table[unit].module = module;
2029 if (cfg) {
2030 nl_table[unit].bind = cfg->bind;
2031 nl_table[unit].unbind = cfg->unbind;
2032 nl_table[unit].flags = cfg->flags;
2033 if (cfg->compare)
2034 nl_table[unit].compare = cfg->compare;
2035 }
2036 nl_table[unit].registered = 1;
2037 } else {
2038 kfree(listeners);
2039 nl_table[unit].registered++;
2040 }
2041 netlink_table_ungrab();
2042 return sk;
2043
2044 out_sock_release:
2045 kfree(listeners);
2046 netlink_kernel_release(sk);
2047 return NULL;
2048
2049 out_sock_release_nosk:
2050 sock_release(sock);
2051 return NULL;
2052 }
2053 EXPORT_SYMBOL(__netlink_kernel_create);
2054
2055 void
netlink_kernel_release(struct sock * sk)2056 netlink_kernel_release(struct sock *sk)
2057 {
2058 if (sk == NULL || sk->sk_socket == NULL)
2059 return;
2060
2061 sock_release(sk->sk_socket);
2062 }
2063 EXPORT_SYMBOL(netlink_kernel_release);
2064
__netlink_change_ngroups(struct sock * sk,unsigned int groups)2065 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2066 {
2067 struct listeners *new, *old;
2068 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2069
2070 if (groups < 32)
2071 groups = 32;
2072
2073 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2074 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2075 if (!new)
2076 return -ENOMEM;
2077 old = nl_deref_protected(tbl->listeners);
2078 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2079 rcu_assign_pointer(tbl->listeners, new);
2080
2081 kfree_rcu(old, rcu);
2082 }
2083 tbl->groups = groups;
2084
2085 return 0;
2086 }
2087
2088 /**
2089 * netlink_change_ngroups - change number of multicast groups
2090 *
2091 * This changes the number of multicast groups that are available
2092 * on a certain netlink family. Note that it is not possible to
2093 * change the number of groups to below 32. Also note that it does
2094 * not implicitly call netlink_clear_multicast_users() when the
2095 * number of groups is reduced.
2096 *
2097 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2098 * @groups: The new number of groups.
2099 */
netlink_change_ngroups(struct sock * sk,unsigned int groups)2100 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2101 {
2102 int err;
2103
2104 netlink_table_grab();
2105 err = __netlink_change_ngroups(sk, groups);
2106 netlink_table_ungrab();
2107
2108 return err;
2109 }
2110
__netlink_clear_multicast_users(struct sock * ksk,unsigned int group)2111 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2112 {
2113 struct sock *sk;
2114 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2115
2116 sk_for_each_bound(sk, &tbl->mc_list)
2117 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2118 }
2119
2120 struct nlmsghdr *
__nlmsg_put(struct sk_buff * skb,u32 portid,u32 seq,int type,int len,int flags)2121 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2122 {
2123 struct nlmsghdr *nlh;
2124 int size = nlmsg_msg_size(len);
2125
2126 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2127 nlh->nlmsg_type = type;
2128 nlh->nlmsg_len = size;
2129 nlh->nlmsg_flags = flags;
2130 nlh->nlmsg_pid = portid;
2131 nlh->nlmsg_seq = seq;
2132 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2133 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2134 return nlh;
2135 }
2136 EXPORT_SYMBOL(__nlmsg_put);
2137
2138 /*
2139 * It looks a bit ugly.
2140 * It would be better to create kernel thread.
2141 */
2142
netlink_dump(struct sock * sk)2143 static int netlink_dump(struct sock *sk)
2144 {
2145 struct netlink_sock *nlk = nlk_sk(sk);
2146 struct netlink_callback *cb;
2147 struct sk_buff *skb = NULL;
2148 struct nlmsghdr *nlh;
2149 struct module *module;
2150 int err = -ENOBUFS;
2151 int alloc_min_size;
2152 int alloc_size;
2153
2154 mutex_lock(nlk->cb_mutex);
2155 if (!nlk->cb_running) {
2156 err = -EINVAL;
2157 goto errout_skb;
2158 }
2159
2160 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2161 goto errout_skb;
2162
2163 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2164 * required, but it makes sense to _attempt_ a 16K bytes allocation
2165 * to reduce number of system calls on dump operations, if user
2166 * ever provided a big enough buffer.
2167 */
2168 cb = &nlk->cb;
2169 alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2170
2171 if (alloc_min_size < nlk->max_recvmsg_len) {
2172 alloc_size = nlk->max_recvmsg_len;
2173 skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
2174 (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) |
2175 __GFP_NOWARN | __GFP_NORETRY);
2176 }
2177 if (!skb) {
2178 alloc_size = alloc_min_size;
2179 skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
2180 GFP_KERNEL);
2181 }
2182 if (!skb)
2183 goto errout_skb;
2184
2185 /* Trim skb to allocated size. User is expected to provide buffer as
2186 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2187 * netlink_recvmsg())). dump will pack as many smaller messages as
2188 * could fit within the allocated skb. skb is typically allocated
2189 * with larger space than required (could be as much as near 2x the
2190 * requested size with align to next power of 2 approach). Allowing
2191 * dump to use the excess space makes it difficult for a user to have a
2192 * reasonable static buffer based on the expected largest dump of a
2193 * single netdev. The outcome is MSG_TRUNC error.
2194 */
2195 skb_reserve(skb, skb_tailroom(skb) - alloc_size);
2196 netlink_skb_set_owner_r(skb, sk);
2197
2198 if (nlk->dump_done_errno > 0)
2199 nlk->dump_done_errno = cb->dump(skb, cb);
2200
2201 if (nlk->dump_done_errno > 0 ||
2202 skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) {
2203 mutex_unlock(nlk->cb_mutex);
2204
2205 if (sk_filter(sk, skb))
2206 kfree_skb(skb);
2207 else
2208 __netlink_sendskb(sk, skb);
2209 return 0;
2210 }
2211
2212 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE,
2213 sizeof(nlk->dump_done_errno), NLM_F_MULTI);
2214 if (WARN_ON(!nlh))
2215 goto errout_skb;
2216
2217 nl_dump_check_consistent(cb, nlh);
2218
2219 memcpy(nlmsg_data(nlh), &nlk->dump_done_errno,
2220 sizeof(nlk->dump_done_errno));
2221
2222 if (sk_filter(sk, skb))
2223 kfree_skb(skb);
2224 else
2225 __netlink_sendskb(sk, skb);
2226
2227 if (cb->done)
2228 cb->done(cb);
2229
2230 nlk->cb_running = false;
2231 module = cb->module;
2232 skb = cb->skb;
2233 mutex_unlock(nlk->cb_mutex);
2234 module_put(module);
2235 consume_skb(skb);
2236 return 0;
2237
2238 errout_skb:
2239 mutex_unlock(nlk->cb_mutex);
2240 kfree_skb(skb);
2241 return err;
2242 }
2243
__netlink_dump_start(struct sock * ssk,struct sk_buff * skb,const struct nlmsghdr * nlh,struct netlink_dump_control * control)2244 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2245 const struct nlmsghdr *nlh,
2246 struct netlink_dump_control *control)
2247 {
2248 struct netlink_callback *cb;
2249 struct sock *sk;
2250 struct netlink_sock *nlk;
2251 int ret;
2252
2253 atomic_inc(&skb->users);
2254
2255 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2256 if (sk == NULL) {
2257 ret = -ECONNREFUSED;
2258 goto error_free;
2259 }
2260
2261 nlk = nlk_sk(sk);
2262 mutex_lock(nlk->cb_mutex);
2263 /* A dump is in progress... */
2264 if (nlk->cb_running) {
2265 ret = -EBUSY;
2266 goto error_unlock;
2267 }
2268 /* add reference of module which cb->dump belongs to */
2269 if (!try_module_get(control->module)) {
2270 ret = -EPROTONOSUPPORT;
2271 goto error_unlock;
2272 }
2273
2274 cb = &nlk->cb;
2275 memset(cb, 0, sizeof(*cb));
2276 cb->start = control->start;
2277 cb->dump = control->dump;
2278 cb->done = control->done;
2279 cb->nlh = nlh;
2280 cb->data = control->data;
2281 cb->module = control->module;
2282 cb->min_dump_alloc = control->min_dump_alloc;
2283 cb->skb = skb;
2284
2285 nlk->cb_running = true;
2286 nlk->dump_done_errno = INT_MAX;
2287
2288 mutex_unlock(nlk->cb_mutex);
2289
2290 if (cb->start)
2291 cb->start(cb);
2292
2293 ret = netlink_dump(sk);
2294 sock_put(sk);
2295
2296 if (ret)
2297 return ret;
2298
2299 /* We successfully started a dump, by returning -EINTR we
2300 * signal not to send ACK even if it was requested.
2301 */
2302 return -EINTR;
2303
2304 error_unlock:
2305 sock_put(sk);
2306 mutex_unlock(nlk->cb_mutex);
2307 error_free:
2308 kfree_skb(skb);
2309 return ret;
2310 }
2311 EXPORT_SYMBOL(__netlink_dump_start);
2312
netlink_ack(struct sk_buff * in_skb,struct nlmsghdr * nlh,int err)2313 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2314 {
2315 struct sk_buff *skb;
2316 struct nlmsghdr *rep;
2317 struct nlmsgerr *errmsg;
2318 size_t payload = sizeof(*errmsg);
2319 struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
2320
2321 /* Error messages get the original request appened, unless the user
2322 * requests to cap the error message.
2323 */
2324 if (!(nlk->flags & NETLINK_F_CAP_ACK) && err)
2325 payload += nlmsg_len(nlh);
2326
2327 skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
2328 NETLINK_CB(in_skb).portid, GFP_KERNEL);
2329 if (!skb) {
2330 struct sock *sk;
2331
2332 sk = netlink_lookup(sock_net(in_skb->sk),
2333 in_skb->sk->sk_protocol,
2334 NETLINK_CB(in_skb).portid);
2335 if (sk) {
2336 sk->sk_err = ENOBUFS;
2337 sk->sk_error_report(sk);
2338 sock_put(sk);
2339 }
2340 return;
2341 }
2342
2343 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2344 NLMSG_ERROR, payload, 0);
2345 errmsg = nlmsg_data(rep);
2346 errmsg->error = err;
2347 memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
2348 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2349 }
2350 EXPORT_SYMBOL(netlink_ack);
2351
netlink_rcv_skb(struct sk_buff * skb,int (* cb)(struct sk_buff *,struct nlmsghdr *))2352 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2353 struct nlmsghdr *))
2354 {
2355 struct nlmsghdr *nlh;
2356 int err;
2357
2358 while (skb->len >= nlmsg_total_size(0)) {
2359 int msglen;
2360
2361 nlh = nlmsg_hdr(skb);
2362 err = 0;
2363
2364 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2365 return 0;
2366
2367 /* Only requests are handled by the kernel */
2368 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2369 goto ack;
2370
2371 /* Skip control messages */
2372 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2373 goto ack;
2374
2375 err = cb(skb, nlh);
2376 if (err == -EINTR)
2377 goto skip;
2378
2379 ack:
2380 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2381 netlink_ack(skb, nlh, err);
2382
2383 skip:
2384 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2385 if (msglen > skb->len)
2386 msglen = skb->len;
2387 skb_pull(skb, msglen);
2388 }
2389
2390 return 0;
2391 }
2392 EXPORT_SYMBOL(netlink_rcv_skb);
2393
2394 /**
2395 * nlmsg_notify - send a notification netlink message
2396 * @sk: netlink socket to use
2397 * @skb: notification message
2398 * @portid: destination netlink portid for reports or 0
2399 * @group: destination multicast group or 0
2400 * @report: 1 to report back, 0 to disable
2401 * @flags: allocation flags
2402 */
nlmsg_notify(struct sock * sk,struct sk_buff * skb,u32 portid,unsigned int group,int report,gfp_t flags)2403 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2404 unsigned int group, int report, gfp_t flags)
2405 {
2406 int err = 0;
2407
2408 if (group) {
2409 int exclude_portid = 0;
2410
2411 if (report) {
2412 atomic_inc(&skb->users);
2413 exclude_portid = portid;
2414 }
2415
2416 /* errors reported via destination sk->sk_err, but propagate
2417 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2418 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2419 if (err == -ESRCH)
2420 err = 0;
2421 }
2422
2423 if (report) {
2424 int err2;
2425
2426 err2 = nlmsg_unicast(sk, skb, portid);
2427 if (!err)
2428 err = err2;
2429 }
2430
2431 return err;
2432 }
2433 EXPORT_SYMBOL(nlmsg_notify);
2434
2435 #ifdef CONFIG_PROC_FS
2436 struct nl_seq_iter {
2437 struct seq_net_private p;
2438 struct rhashtable_iter hti;
2439 int link;
2440 };
2441
netlink_walk_start(struct nl_seq_iter * iter)2442 static int netlink_walk_start(struct nl_seq_iter *iter)
2443 {
2444 int err;
2445
2446 err = rhashtable_walk_init(&nl_table[iter->link].hash, &iter->hti);
2447 if (err) {
2448 iter->link = MAX_LINKS;
2449 return err;
2450 }
2451
2452 err = rhashtable_walk_start(&iter->hti);
2453 return err == -EAGAIN ? 0 : err;
2454 }
2455
netlink_walk_stop(struct nl_seq_iter * iter)2456 static void netlink_walk_stop(struct nl_seq_iter *iter)
2457 {
2458 rhashtable_walk_stop(&iter->hti);
2459 rhashtable_walk_exit(&iter->hti);
2460 }
2461
__netlink_seq_next(struct seq_file * seq)2462 static void *__netlink_seq_next(struct seq_file *seq)
2463 {
2464 struct nl_seq_iter *iter = seq->private;
2465 struct netlink_sock *nlk;
2466
2467 do {
2468 for (;;) {
2469 int err;
2470
2471 nlk = rhashtable_walk_next(&iter->hti);
2472
2473 if (IS_ERR(nlk)) {
2474 if (PTR_ERR(nlk) == -EAGAIN)
2475 continue;
2476
2477 return nlk;
2478 }
2479
2480 if (nlk)
2481 break;
2482
2483 netlink_walk_stop(iter);
2484 if (++iter->link >= MAX_LINKS)
2485 return NULL;
2486
2487 err = netlink_walk_start(iter);
2488 if (err)
2489 return ERR_PTR(err);
2490 }
2491 } while (sock_net(&nlk->sk) != seq_file_net(seq));
2492
2493 return nlk;
2494 }
2495
netlink_seq_start(struct seq_file * seq,loff_t * posp)2496 static void *netlink_seq_start(struct seq_file *seq, loff_t *posp)
2497 {
2498 struct nl_seq_iter *iter = seq->private;
2499 void *obj = SEQ_START_TOKEN;
2500 loff_t pos;
2501 int err;
2502
2503 iter->link = 0;
2504
2505 err = netlink_walk_start(iter);
2506 if (err)
2507 return ERR_PTR(err);
2508
2509 for (pos = *posp; pos && obj && !IS_ERR(obj); pos--)
2510 obj = __netlink_seq_next(seq);
2511
2512 return obj;
2513 }
2514
netlink_seq_next(struct seq_file * seq,void * v,loff_t * pos)2515 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2516 {
2517 ++*pos;
2518 return __netlink_seq_next(seq);
2519 }
2520
netlink_seq_stop(struct seq_file * seq,void * v)2521 static void netlink_seq_stop(struct seq_file *seq, void *v)
2522 {
2523 struct nl_seq_iter *iter = seq->private;
2524
2525 if (iter->link >= MAX_LINKS)
2526 return;
2527
2528 netlink_walk_stop(iter);
2529 }
2530
2531
netlink_seq_show(struct seq_file * seq,void * v)2532 static int netlink_seq_show(struct seq_file *seq, void *v)
2533 {
2534 if (v == SEQ_START_TOKEN) {
2535 seq_puts(seq,
2536 "sk Eth Pid Groups "
2537 "Rmem Wmem Dump Locks Drops Inode\n");
2538 } else {
2539 struct sock *s = v;
2540 struct netlink_sock *nlk = nlk_sk(s);
2541
2542 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2543 s,
2544 s->sk_protocol,
2545 nlk->portid,
2546 nlk->groups ? (u32)nlk->groups[0] : 0,
2547 sk_rmem_alloc_get(s),
2548 sk_wmem_alloc_get(s),
2549 nlk->cb_running,
2550 atomic_read(&s->sk_refcnt),
2551 atomic_read(&s->sk_drops),
2552 sock_i_ino(s)
2553 );
2554
2555 }
2556 return 0;
2557 }
2558
2559 static const struct seq_operations netlink_seq_ops = {
2560 .start = netlink_seq_start,
2561 .next = netlink_seq_next,
2562 .stop = netlink_seq_stop,
2563 .show = netlink_seq_show,
2564 };
2565
2566
netlink_seq_open(struct inode * inode,struct file * file)2567 static int netlink_seq_open(struct inode *inode, struct file *file)
2568 {
2569 return seq_open_net(inode, file, &netlink_seq_ops,
2570 sizeof(struct nl_seq_iter));
2571 }
2572
2573 static const struct file_operations netlink_seq_fops = {
2574 .owner = THIS_MODULE,
2575 .open = netlink_seq_open,
2576 .read = seq_read,
2577 .llseek = seq_lseek,
2578 .release = seq_release_net,
2579 };
2580
2581 #endif
2582
netlink_register_notifier(struct notifier_block * nb)2583 int netlink_register_notifier(struct notifier_block *nb)
2584 {
2585 return atomic_notifier_chain_register(&netlink_chain, nb);
2586 }
2587 EXPORT_SYMBOL(netlink_register_notifier);
2588
netlink_unregister_notifier(struct notifier_block * nb)2589 int netlink_unregister_notifier(struct notifier_block *nb)
2590 {
2591 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2592 }
2593 EXPORT_SYMBOL(netlink_unregister_notifier);
2594
2595 static const struct proto_ops netlink_ops = {
2596 .family = PF_NETLINK,
2597 .owner = THIS_MODULE,
2598 .release = netlink_release,
2599 .bind = netlink_bind,
2600 .connect = netlink_connect,
2601 .socketpair = sock_no_socketpair,
2602 .accept = sock_no_accept,
2603 .getname = netlink_getname,
2604 .poll = datagram_poll,
2605 .ioctl = sock_no_ioctl,
2606 .listen = sock_no_listen,
2607 .shutdown = sock_no_shutdown,
2608 .setsockopt = netlink_setsockopt,
2609 .getsockopt = netlink_getsockopt,
2610 .sendmsg = netlink_sendmsg,
2611 .recvmsg = netlink_recvmsg,
2612 .mmap = sock_no_mmap,
2613 .sendpage = sock_no_sendpage,
2614 };
2615
2616 static const struct net_proto_family netlink_family_ops = {
2617 .family = PF_NETLINK,
2618 .create = netlink_create,
2619 .owner = THIS_MODULE, /* for consistency 8) */
2620 };
2621
netlink_net_init(struct net * net)2622 static int __net_init netlink_net_init(struct net *net)
2623 {
2624 #ifdef CONFIG_PROC_FS
2625 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
2626 return -ENOMEM;
2627 #endif
2628 return 0;
2629 }
2630
netlink_net_exit(struct net * net)2631 static void __net_exit netlink_net_exit(struct net *net)
2632 {
2633 #ifdef CONFIG_PROC_FS
2634 remove_proc_entry("netlink", net->proc_net);
2635 #endif
2636 }
2637
netlink_add_usersock_entry(void)2638 static void __init netlink_add_usersock_entry(void)
2639 {
2640 struct listeners *listeners;
2641 int groups = 32;
2642
2643 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2644 if (!listeners)
2645 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2646
2647 netlink_table_grab();
2648
2649 nl_table[NETLINK_USERSOCK].groups = groups;
2650 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2651 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2652 nl_table[NETLINK_USERSOCK].registered = 1;
2653 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2654
2655 netlink_table_ungrab();
2656 }
2657
2658 static struct pernet_operations __net_initdata netlink_net_ops = {
2659 .init = netlink_net_init,
2660 .exit = netlink_net_exit,
2661 };
2662
netlink_hash(const void * data,u32 len,u32 seed)2663 static inline u32 netlink_hash(const void *data, u32 len, u32 seed)
2664 {
2665 const struct netlink_sock *nlk = data;
2666 struct netlink_compare_arg arg;
2667
2668 netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid);
2669 return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed);
2670 }
2671
2672 static const struct rhashtable_params netlink_rhashtable_params = {
2673 .head_offset = offsetof(struct netlink_sock, node),
2674 .key_len = netlink_compare_arg_len,
2675 .obj_hashfn = netlink_hash,
2676 .obj_cmpfn = netlink_compare,
2677 .automatic_shrinking = true,
2678 };
2679
netlink_proto_init(void)2680 static int __init netlink_proto_init(void)
2681 {
2682 int i;
2683 int err = proto_register(&netlink_proto, 0);
2684
2685 if (err != 0)
2686 goto out;
2687
2688 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
2689
2690 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2691 if (!nl_table)
2692 goto panic;
2693
2694 for (i = 0; i < MAX_LINKS; i++) {
2695 if (rhashtable_init(&nl_table[i].hash,
2696 &netlink_rhashtable_params) < 0) {
2697 while (--i > 0)
2698 rhashtable_destroy(&nl_table[i].hash);
2699 kfree(nl_table);
2700 goto panic;
2701 }
2702 }
2703
2704 INIT_LIST_HEAD(&netlink_tap_all);
2705
2706 netlink_add_usersock_entry();
2707
2708 sock_register(&netlink_family_ops);
2709 register_pernet_subsys(&netlink_net_ops);
2710 /* The netlink device handler may be needed early. */
2711 rtnetlink_init();
2712 out:
2713 return err;
2714 panic:
2715 panic("netlink_init: Cannot allocate nl_table\n");
2716 }
2717
2718 core_initcall(netlink_proto_init);
2719