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