1 /* Netfilter messages via netlink socket. Allows for user space
2 * protocol helpers and general trouble making from userspace.
3 *
4 * (C) 2001 by Jay Schulist <jschlst@samba.org>,
5 * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
6 * (C) 2005-2017 by Pablo Neira Ayuso <pablo@netfilter.org>
7 *
8 * Initial netfilter messages via netlink development funded and
9 * generally made possible by Network Robots, Inc. (www.networkrobots.com)
10 *
11 * Further development of this code funded by Astaro AG (http://www.astaro.com)
12 *
13 * This software may be used and distributed according to the terms
14 * of the GNU General Public License, incorporated herein by reference.
15 */
16
17 #include <linux/module.h>
18 #include <linux/types.h>
19 #include <linux/socket.h>
20 #include <linux/kernel.h>
21 #include <linux/string.h>
22 #include <linux/sockios.h>
23 #include <linux/net.h>
24 #include <linux/skbuff.h>
25 #include <linux/uaccess.h>
26 #include <net/sock.h>
27 #include <linux/init.h>
28 #include <linux/sched/signal.h>
29
30 #include <net/netlink.h>
31 #include <net/netns/generic.h>
32 #include <linux/netfilter.h>
33 #include <linux/netfilter/nfnetlink.h>
34
35 MODULE_LICENSE("GPL");
36 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
37 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
38 MODULE_DESCRIPTION("Netfilter messages via netlink socket");
39
40 #define nfnl_dereference_protected(id) \
41 rcu_dereference_protected(table[(id)].subsys, \
42 lockdep_nfnl_is_held((id)))
43
44 #define NFNL_MAX_ATTR_COUNT 32
45
46 static unsigned int nfnetlink_pernet_id __read_mostly;
47
48 #ifdef CONFIG_NF_CONNTRACK_EVENTS
49 static DEFINE_SPINLOCK(nfnl_grp_active_lock);
50 #endif
51
52 struct nfnl_net {
53 struct sock *nfnl;
54 };
55
56 static struct {
57 struct mutex mutex;
58 const struct nfnetlink_subsystem __rcu *subsys;
59 } table[NFNL_SUBSYS_COUNT];
60
61 static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT];
62
63 static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = {
64 [NFNL_SUBSYS_NONE] = "nfnl_subsys_none",
65 [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink",
66 [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp",
67 [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue",
68 [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog",
69 [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf",
70 [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset",
71 [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct",
72 [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout",
73 [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper",
74 [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables",
75 [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat",
76 [NFNL_SUBSYS_HOOK] = "nfnl_subsys_hook",
77 };
78
79 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
80 [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
81 [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK,
82 [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK,
83 [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
84 [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
85 [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
86 [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES,
87 [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT,
88 [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES,
89 };
90
91 static struct nfnl_net *nfnl_pernet(struct net *net)
92 {
93 return net_generic(net, nfnetlink_pernet_id);
94 }
95
96 void nfnl_lock(__u8 subsys_id)
97 {
98 mutex_lock(&table[subsys_id].mutex);
99 }
100 EXPORT_SYMBOL_GPL(nfnl_lock);
101
102 void nfnl_unlock(__u8 subsys_id)
103 {
104 mutex_unlock(&table[subsys_id].mutex);
105 }
106 EXPORT_SYMBOL_GPL(nfnl_unlock);
107
108 #ifdef CONFIG_PROVE_LOCKING
109 bool lockdep_nfnl_is_held(u8 subsys_id)
110 {
111 return lockdep_is_held(&table[subsys_id].mutex);
112 }
113 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
114 #endif
115
116 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
117 {
118 u8 cb_id;
119
120 /* Sanity-check attr_count size to avoid stack buffer overflow. */
121 for (cb_id = 0; cb_id < n->cb_count; cb_id++)
122 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
123 return -EINVAL;
124
125 nfnl_lock(n->subsys_id);
126 if (table[n->subsys_id].subsys) {
127 nfnl_unlock(n->subsys_id);
128 return -EBUSY;
129 }
130 rcu_assign_pointer(table[n->subsys_id].subsys, n);
131 nfnl_unlock(n->subsys_id);
132
133 return 0;
134 }
135 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
136
137 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
138 {
139 nfnl_lock(n->subsys_id);
140 table[n->subsys_id].subsys = NULL;
141 nfnl_unlock(n->subsys_id);
142 synchronize_rcu();
143 return 0;
144 }
145 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
146
147 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
148 {
149 u8 subsys_id = NFNL_SUBSYS_ID(type);
150
151 if (subsys_id >= NFNL_SUBSYS_COUNT)
152 return NULL;
153
154 return rcu_dereference(table[subsys_id].subsys);
155 }
156
157 static inline const struct nfnl_callback *
158 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
159 {
160 u8 cb_id = NFNL_MSG_TYPE(type);
161
162 if (cb_id >= ss->cb_count)
163 return NULL;
164
165 return &ss->cb[cb_id];
166 }
167
168 int nfnetlink_has_listeners(struct net *net, unsigned int group)
169 {
170 struct nfnl_net *nfnlnet = nfnl_pernet(net);
171
172 return netlink_has_listeners(nfnlnet->nfnl, group);
173 }
174 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
175
176 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
177 unsigned int group, int echo, gfp_t flags)
178 {
179 struct nfnl_net *nfnlnet = nfnl_pernet(net);
180
181 return nlmsg_notify(nfnlnet->nfnl, skb, portid, group, echo, flags);
182 }
183 EXPORT_SYMBOL_GPL(nfnetlink_send);
184
185 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
186 {
187 struct nfnl_net *nfnlnet = nfnl_pernet(net);
188
189 return netlink_set_err(nfnlnet->nfnl, portid, group, error);
190 }
191 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
192
193 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid)
194 {
195 struct nfnl_net *nfnlnet = nfnl_pernet(net);
196 int err;
197
198 err = nlmsg_unicast(nfnlnet->nfnl, skb, portid);
199 if (err == -EAGAIN)
200 err = -ENOBUFS;
201
202 return err;
203 }
204 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
205
206 void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid,
207 __u32 group, gfp_t allocation)
208 {
209 struct nfnl_net *nfnlnet = nfnl_pernet(net);
210
211 netlink_broadcast(nfnlnet->nfnl, skb, portid, group, allocation);
212 }
213 EXPORT_SYMBOL_GPL(nfnetlink_broadcast);
214
215 /* Process one complete nfnetlink message. */
216 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
217 struct netlink_ext_ack *extack)
218 {
219 struct net *net = sock_net(skb->sk);
220 const struct nfnl_callback *nc;
221 const struct nfnetlink_subsystem *ss;
222 int type, err;
223
224 /* All the messages must at least contain nfgenmsg */
225 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
226 return 0;
227
228 type = nlh->nlmsg_type;
229 replay:
230 rcu_read_lock();
231
232 ss = nfnetlink_get_subsys(type);
233 if (!ss) {
234 #ifdef CONFIG_MODULES
235 rcu_read_unlock();
236 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
237 rcu_read_lock();
238 ss = nfnetlink_get_subsys(type);
239 if (!ss)
240 #endif
241 {
242 rcu_read_unlock();
243 return -EINVAL;
244 }
245 }
246
247 nc = nfnetlink_find_client(type, ss);
248 if (!nc) {
249 rcu_read_unlock();
250 return -EINVAL;
251 }
252
253 {
254 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
255 struct nfnl_net *nfnlnet = nfnl_pernet(net);
256 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
257 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
258 struct nlattr *attr = (void *)nlh + min_len;
259 int attrlen = nlh->nlmsg_len - min_len;
260 __u8 subsys_id = NFNL_SUBSYS_ID(type);
261 struct nfnl_info info = {
262 .net = net,
263 .sk = nfnlnet->nfnl,
264 .nlh = nlh,
265 .nfmsg = nlmsg_data(nlh),
266 .extack = extack,
267 };
268
269 /* Sanity-check NFNL_MAX_ATTR_COUNT */
270 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
271 rcu_read_unlock();
272 return -ENOMEM;
273 }
274
275 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
276 attr, attrlen,
277 ss->cb[cb_id].policy, extack);
278 if (err < 0) {
279 rcu_read_unlock();
280 return err;
281 }
282
283 if (!nc->call) {
284 rcu_read_unlock();
285 return -EINVAL;
286 }
287
288 switch (nc->type) {
289 case NFNL_CB_RCU:
290 err = nc->call(skb, &info, (const struct nlattr **)cda);
291 rcu_read_unlock();
292 break;
293 case NFNL_CB_MUTEX:
294 rcu_read_unlock();
295 nfnl_lock(subsys_id);
296 if (nfnl_dereference_protected(subsys_id) != ss ||
297 nfnetlink_find_client(type, ss) != nc) {
298 nfnl_unlock(subsys_id);
299 err = -EAGAIN;
300 break;
301 }
302 err = nc->call(skb, &info, (const struct nlattr **)cda);
303 nfnl_unlock(subsys_id);
304 break;
305 default:
306 rcu_read_unlock();
307 err = -EINVAL;
308 break;
309 }
310 if (err == -EAGAIN)
311 goto replay;
312 return err;
313 }
314 }
315
316 struct nfnl_err {
317 struct list_head head;
318 struct nlmsghdr *nlh;
319 int err;
320 struct netlink_ext_ack extack;
321 };
322
323 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
324 const struct netlink_ext_ack *extack)
325 {
326 struct nfnl_err *nfnl_err;
327
328 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
329 if (nfnl_err == NULL)
330 return -ENOMEM;
331
332 nfnl_err->nlh = nlh;
333 nfnl_err->err = err;
334 nfnl_err->extack = *extack;
335 list_add_tail(&nfnl_err->head, list);
336
337 return 0;
338 }
339
340 static void nfnl_err_del(struct nfnl_err *nfnl_err)
341 {
342 list_del(&nfnl_err->head);
343 kfree(nfnl_err);
344 }
345
346 static void nfnl_err_reset(struct list_head *err_list)
347 {
348 struct nfnl_err *nfnl_err, *next;
349
350 list_for_each_entry_safe(nfnl_err, next, err_list, head)
351 nfnl_err_del(nfnl_err);
352 }
353
354 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
355 {
356 struct nfnl_err *nfnl_err, *next;
357
358 list_for_each_entry_safe(nfnl_err, next, err_list, head) {
359 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
360 &nfnl_err->extack);
361 nfnl_err_del(nfnl_err);
362 }
363 }
364
365 enum {
366 NFNL_BATCH_FAILURE = (1 << 0),
367 NFNL_BATCH_DONE = (1 << 1),
368 NFNL_BATCH_REPLAY = (1 << 2),
369 };
370
371 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
372 u16 subsys_id, u32 genid)
373 {
374 struct sk_buff *oskb = skb;
375 struct net *net = sock_net(skb->sk);
376 const struct nfnetlink_subsystem *ss;
377 const struct nfnl_callback *nc;
378 struct netlink_ext_ack extack;
379 LIST_HEAD(err_list);
380 u32 status;
381 int err;
382
383 if (subsys_id >= NFNL_SUBSYS_COUNT)
384 return netlink_ack(skb, nlh, -EINVAL, NULL);
385 replay:
386 status = 0;
387 replay_abort:
388 skb = netlink_skb_clone(oskb, GFP_KERNEL);
389 if (!skb)
390 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
391
392 nfnl_lock(subsys_id);
393 ss = nfnl_dereference_protected(subsys_id);
394 if (!ss) {
395 #ifdef CONFIG_MODULES
396 nfnl_unlock(subsys_id);
397 request_module("nfnetlink-subsys-%d", subsys_id);
398 nfnl_lock(subsys_id);
399 ss = nfnl_dereference_protected(subsys_id);
400 if (!ss)
401 #endif
402 {
403 nfnl_unlock(subsys_id);
404 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
405 return kfree_skb(skb);
406 }
407 }
408
409 if (!ss->valid_genid || !ss->commit || !ss->abort) {
410 nfnl_unlock(subsys_id);
411 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
412 return kfree_skb(skb);
413 }
414
415 if (!try_module_get(ss->owner)) {
416 nfnl_unlock(subsys_id);
417 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
418 return kfree_skb(skb);
419 }
420
421 if (!ss->valid_genid(net, genid)) {
422 module_put(ss->owner);
423 nfnl_unlock(subsys_id);
424 netlink_ack(oskb, nlh, -ERESTART, NULL);
425 return kfree_skb(skb);
426 }
427
428 nfnl_unlock(subsys_id);
429
430 if (nlh->nlmsg_flags & NLM_F_ACK)
431 nfnl_err_add(&err_list, nlh, 0, &extack);
432
433 while (skb->len >= nlmsg_total_size(0)) {
434 int msglen, type;
435
436 if (fatal_signal_pending(current)) {
437 nfnl_err_reset(&err_list);
438 err = -EINTR;
439 status = NFNL_BATCH_FAILURE;
440 goto done;
441 }
442
443 memset(&extack, 0, sizeof(extack));
444 nlh = nlmsg_hdr(skb);
445 err = 0;
446
447 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
448 skb->len < nlh->nlmsg_len ||
449 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
450 nfnl_err_reset(&err_list);
451 status |= NFNL_BATCH_FAILURE;
452 goto done;
453 }
454
455 /* Only requests are handled by the kernel */
456 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
457 err = -EINVAL;
458 goto ack;
459 }
460
461 type = nlh->nlmsg_type;
462 if (type == NFNL_MSG_BATCH_BEGIN) {
463 /* Malformed: Batch begin twice */
464 nfnl_err_reset(&err_list);
465 status |= NFNL_BATCH_FAILURE;
466 goto done;
467 } else if (type == NFNL_MSG_BATCH_END) {
468 status |= NFNL_BATCH_DONE;
469 goto done;
470 } else if (type < NLMSG_MIN_TYPE) {
471 err = -EINVAL;
472 goto ack;
473 }
474
475 /* We only accept a batch with messages for the same
476 * subsystem.
477 */
478 if (NFNL_SUBSYS_ID(type) != subsys_id) {
479 err = -EINVAL;
480 goto ack;
481 }
482
483 nc = nfnetlink_find_client(type, ss);
484 if (!nc) {
485 err = -EINVAL;
486 goto ack;
487 }
488
489 if (nc->type != NFNL_CB_BATCH) {
490 err = -EINVAL;
491 goto ack;
492 }
493
494 {
495 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
496 struct nfnl_net *nfnlnet = nfnl_pernet(net);
497 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
498 struct nlattr *attr = (void *)nlh + min_len;
499 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
500 int attrlen = nlh->nlmsg_len - min_len;
501 struct nfnl_info info = {
502 .net = net,
503 .sk = nfnlnet->nfnl,
504 .nlh = nlh,
505 .nfmsg = nlmsg_data(nlh),
506 .extack = &extack,
507 };
508
509 /* Sanity-check NFTA_MAX_ATTR */
510 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
511 err = -ENOMEM;
512 goto ack;
513 }
514
515 err = nla_parse_deprecated(cda,
516 ss->cb[cb_id].attr_count,
517 attr, attrlen,
518 ss->cb[cb_id].policy, NULL);
519 if (err < 0)
520 goto ack;
521
522 err = nc->call(skb, &info, (const struct nlattr **)cda);
523
524 /* The lock was released to autoload some module, we
525 * have to abort and start from scratch using the
526 * original skb.
527 */
528 if (err == -EAGAIN) {
529 status |= NFNL_BATCH_REPLAY;
530 goto done;
531 }
532 }
533 ack:
534 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
535 /* Errors are delivered once the full batch has been
536 * processed, this avoids that the same error is
537 * reported several times when replaying the batch.
538 */
539 if (err == -ENOMEM ||
540 nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
541 /* We failed to enqueue an error, reset the
542 * list of errors and send OOM to userspace
543 * pointing to the batch header.
544 */
545 nfnl_err_reset(&err_list);
546 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
547 NULL);
548 status |= NFNL_BATCH_FAILURE;
549 goto done;
550 }
551 /* We don't stop processing the batch on errors, thus,
552 * userspace gets all the errors that the batch
553 * triggers.
554 */
555 if (err)
556 status |= NFNL_BATCH_FAILURE;
557 }
558
559 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
560 if (msglen > skb->len)
561 msglen = skb->len;
562 skb_pull(skb, msglen);
563 }
564 done:
565 if (status & NFNL_BATCH_REPLAY) {
566 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD);
567 nfnl_err_reset(&err_list);
568 kfree_skb(skb);
569 module_put(ss->owner);
570 goto replay;
571 } else if (status == NFNL_BATCH_DONE) {
572 err = ss->commit(net, oskb);
573 if (err == -EAGAIN) {
574 status |= NFNL_BATCH_REPLAY;
575 goto done;
576 } else if (err) {
577 ss->abort(net, oskb, NFNL_ABORT_NONE);
578 netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
579 } else if (nlh->nlmsg_flags & NLM_F_ACK) {
580 nfnl_err_add(&err_list, nlh, 0, &extack);
581 }
582 } else {
583 enum nfnl_abort_action abort_action;
584
585 if (status & NFNL_BATCH_FAILURE)
586 abort_action = NFNL_ABORT_NONE;
587 else
588 abort_action = NFNL_ABORT_VALIDATE;
589
590 err = ss->abort(net, oskb, abort_action);
591 if (err == -EAGAIN) {
592 nfnl_err_reset(&err_list);
593 kfree_skb(skb);
594 module_put(ss->owner);
595 status |= NFNL_BATCH_FAILURE;
596 goto replay_abort;
597 }
598 }
599
600 nfnl_err_deliver(&err_list, oskb);
601 kfree_skb(skb);
602 module_put(ss->owner);
603 }
604
605 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
606 [NFNL_BATCH_GENID] = { .type = NLA_U32 },
607 };
608
609 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
610 {
611 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
612 struct nlattr *attr = (void *)nlh + min_len;
613 struct nlattr *cda[NFNL_BATCH_MAX + 1];
614 int attrlen = nlh->nlmsg_len - min_len;
615 struct nfgenmsg *nfgenmsg;
616 int msglen, err;
617 u32 gen_id = 0;
618 u16 res_id;
619
620 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
621 if (msglen > skb->len)
622 msglen = skb->len;
623
624 if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
625 return;
626
627 err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
628 nfnl_batch_policy, NULL);
629 if (err < 0) {
630 netlink_ack(skb, nlh, err, NULL);
631 return;
632 }
633 if (cda[NFNL_BATCH_GENID])
634 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
635
636 nfgenmsg = nlmsg_data(nlh);
637 skb_pull(skb, msglen);
638 /* Work around old nft using host byte order */
639 if (nfgenmsg->res_id == (__force __be16)NFNL_SUBSYS_NFTABLES)
640 res_id = NFNL_SUBSYS_NFTABLES;
641 else
642 res_id = ntohs(nfgenmsg->res_id);
643
644 nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
645 }
646
647 static void nfnetlink_rcv(struct sk_buff *skb)
648 {
649 struct nlmsghdr *nlh = nlmsg_hdr(skb);
650
651 if (skb->len < NLMSG_HDRLEN ||
652 nlh->nlmsg_len < NLMSG_HDRLEN ||
653 skb->len < nlh->nlmsg_len)
654 return;
655
656 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
657 netlink_ack(skb, nlh, -EPERM, NULL);
658 return;
659 }
660
661 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
662 nfnetlink_rcv_skb_batch(skb, nlh);
663 else
664 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
665 }
666
667 static void nfnetlink_bind_event(struct net *net, unsigned int group)
668 {
669 #ifdef CONFIG_NF_CONNTRACK_EVENTS
670 int type, group_bit;
671 u8 v;
672
673 /* All NFNLGRP_CONNTRACK_* group bits fit into u8.
674 * The other groups are not relevant and can be ignored.
675 */
676 if (group >= 8)
677 return;
678
679 type = nfnl_group2type[group];
680
681 switch (type) {
682 case NFNL_SUBSYS_CTNETLINK:
683 break;
684 case NFNL_SUBSYS_CTNETLINK_EXP:
685 break;
686 default:
687 return;
688 }
689
690 group_bit = (1 << group);
691
692 spin_lock(&nfnl_grp_active_lock);
693 v = READ_ONCE(nf_ctnetlink_has_listener);
694 if ((v & group_bit) == 0) {
695 v |= group_bit;
696
697 /* read concurrently without nfnl_grp_active_lock held. */
698 WRITE_ONCE(nf_ctnetlink_has_listener, v);
699 }
700
701 spin_unlock(&nfnl_grp_active_lock);
702 #endif
703 }
704
705 static int nfnetlink_bind(struct net *net, int group)
706 {
707 const struct nfnetlink_subsystem *ss;
708 int type;
709
710 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
711 return 0;
712
713 type = nfnl_group2type[group];
714
715 rcu_read_lock();
716 ss = nfnetlink_get_subsys(type << 8);
717 rcu_read_unlock();
718 if (!ss)
719 request_module_nowait("nfnetlink-subsys-%d", type);
720
721 nfnetlink_bind_event(net, group);
722 return 0;
723 }
724
725 static void nfnetlink_unbind(struct net *net, int group)
726 {
727 #ifdef CONFIG_NF_CONNTRACK_EVENTS
728 int type, group_bit;
729
730 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
731 return;
732
733 type = nfnl_group2type[group];
734
735 switch (type) {
736 case NFNL_SUBSYS_CTNETLINK:
737 break;
738 case NFNL_SUBSYS_CTNETLINK_EXP:
739 break;
740 default:
741 return;
742 }
743
744 /* ctnetlink_has_listener is u8 */
745 if (group >= 8)
746 return;
747
748 group_bit = (1 << group);
749
750 spin_lock(&nfnl_grp_active_lock);
751 if (!nfnetlink_has_listeners(net, group)) {
752 u8 v = READ_ONCE(nf_ctnetlink_has_listener);
753
754 v &= ~group_bit;
755
756 /* read concurrently without nfnl_grp_active_lock held. */
757 WRITE_ONCE(nf_ctnetlink_has_listener, v);
758 }
759 spin_unlock(&nfnl_grp_active_lock);
760 #endif
761 }
762
763 static int __net_init nfnetlink_net_init(struct net *net)
764 {
765 struct nfnl_net *nfnlnet = nfnl_pernet(net);
766 struct netlink_kernel_cfg cfg = {
767 .groups = NFNLGRP_MAX,
768 .input = nfnetlink_rcv,
769 .bind = nfnetlink_bind,
770 .unbind = nfnetlink_unbind,
771 };
772
773 nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
774 if (!nfnlnet->nfnl)
775 return -ENOMEM;
776 return 0;
777 }
778
779 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
780 {
781 struct nfnl_net *nfnlnet;
782 struct net *net;
783
784 list_for_each_entry(net, net_exit_list, exit_list) {
785 nfnlnet = nfnl_pernet(net);
786
787 netlink_kernel_release(nfnlnet->nfnl);
788 }
789 }
790
791 static struct pernet_operations nfnetlink_net_ops = {
792 .init = nfnetlink_net_init,
793 .exit_batch = nfnetlink_net_exit_batch,
794 .id = &nfnetlink_pernet_id,
795 .size = sizeof(struct nfnl_net),
796 };
797
798 static int __init nfnetlink_init(void)
799 {
800 int i;
801
802 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
803 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
804
805 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
806 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]);
807
808 return register_pernet_subsys(&nfnetlink_net_ops);
809 }
810
811 static void __exit nfnetlink_exit(void)
812 {
813 unregister_pernet_subsys(&nfnetlink_net_ops);
814 }
815 module_init(nfnetlink_init);
816 module_exit(nfnetlink_exit);
817
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