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