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net/compat: Add missing sock updates for SCM_RIGHTS
[linux/fpc-iii.git] / net / netfilter / nfnetlink.c
blob99127e2d95a842e5b8e45da4847715e62709ca4c
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 <linux/netfilter/nfnetlink.h>
32
33 MODULE_LICENSE("GPL");
34 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
35 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
36
37 #define nfnl_dereference_protected(id) \
38 rcu_dereference_protected(table[(id)].subsys, \
39 lockdep_nfnl_is_held((id)))
40
41 #define NFNL_MAX_ATTR_COUNT 32
42
43 static struct {
44 struct mutex mutex;
45 const struct nfnetlink_subsystem __rcu *subsys;
46 } table[NFNL_SUBSYS_COUNT];
47
48 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
49 [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
50 [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK,
51 [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK,
52 [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
53 [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
54 [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
55 [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES,
56 [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT,
57 [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES,
58 };
59
60 void nfnl_lock(__u8 subsys_id)
61 {
62 mutex_lock(&table[subsys_id].mutex);
63 }
64 EXPORT_SYMBOL_GPL(nfnl_lock);
65
66 void nfnl_unlock(__u8 subsys_id)
67 {
68 mutex_unlock(&table[subsys_id].mutex);
69 }
70 EXPORT_SYMBOL_GPL(nfnl_unlock);
71
72 #ifdef CONFIG_PROVE_LOCKING
73 bool lockdep_nfnl_is_held(u8 subsys_id)
74 {
75 return lockdep_is_held(&table[subsys_id].mutex);
76 }
77 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
78 #endif
79
80 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
81 {
82 u8 cb_id;
83
84 /* Sanity-check attr_count size to avoid stack buffer overflow. */
85 for (cb_id = 0; cb_id < n->cb_count; cb_id++)
86 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
87 return -EINVAL;
88
89 nfnl_lock(n->subsys_id);
90 if (table[n->subsys_id].subsys) {
91 nfnl_unlock(n->subsys_id);
92 return -EBUSY;
93 }
94 rcu_assign_pointer(table[n->subsys_id].subsys, n);
95 nfnl_unlock(n->subsys_id);
96
97 return 0;
98 }
99 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
100
101 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
102 {
103 nfnl_lock(n->subsys_id);
104 table[n->subsys_id].subsys = NULL;
105 nfnl_unlock(n->subsys_id);
106 synchronize_rcu();
107 return 0;
108 }
109 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
110
111 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
112 {
113 u8 subsys_id = NFNL_SUBSYS_ID(type);
114
115 if (subsys_id >= NFNL_SUBSYS_COUNT)
116 return NULL;
117
118 return rcu_dereference(table[subsys_id].subsys);
119 }
120
121 static inline const struct nfnl_callback *
122 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
123 {
124 u8 cb_id = NFNL_MSG_TYPE(type);
125
126 if (cb_id >= ss->cb_count)
127 return NULL;
128
129 return &ss->cb[cb_id];
130 }
131
132 int nfnetlink_has_listeners(struct net *net, unsigned int group)
133 {
134 return netlink_has_listeners(net->nfnl, group);
135 }
136 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
137
138 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
139 unsigned int group, int echo, gfp_t flags)
140 {
141 return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags);
142 }
143 EXPORT_SYMBOL_GPL(nfnetlink_send);
144
145 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
146 {
147 return netlink_set_err(net->nfnl, portid, group, error);
148 }
149 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
150
151 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid,
152 int flags)
153 {
154 return netlink_unicast(net->nfnl, skb, portid, flags);
155 }
156 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
157
158 /* Process one complete nfnetlink message. */
159 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
160 struct netlink_ext_ack *extack)
161 {
162 struct net *net = sock_net(skb->sk);
163 const struct nfnl_callback *nc;
164 const struct nfnetlink_subsystem *ss;
165 int type, err;
166
167 /* All the messages must at least contain nfgenmsg */
168 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
169 return 0;
170
171 type = nlh->nlmsg_type;
172 replay:
173 rcu_read_lock();
174 ss = nfnetlink_get_subsys(type);
175 if (!ss) {
176 #ifdef CONFIG_MODULES
177 rcu_read_unlock();
178 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
179 rcu_read_lock();
180 ss = nfnetlink_get_subsys(type);
181 if (!ss)
182 #endif
183 {
184 rcu_read_unlock();
185 return -EINVAL;
186 }
187 }
188
189 nc = nfnetlink_find_client(type, ss);
190 if (!nc) {
191 rcu_read_unlock();
192 return -EINVAL;
193 }
194
195 {
196 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
197 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
198 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
199 struct nlattr *attr = (void *)nlh + min_len;
200 int attrlen = nlh->nlmsg_len - min_len;
201 __u8 subsys_id = NFNL_SUBSYS_ID(type);
202
203 /* Sanity-check NFNL_MAX_ATTR_COUNT */
204 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
205 rcu_read_unlock();
206 return -ENOMEM;
207 }
208
209 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
210 attr, attrlen,
211 ss->cb[cb_id].policy, extack);
212 if (err < 0) {
213 rcu_read_unlock();
214 return err;
215 }
216
217 if (nc->call_rcu) {
218 err = nc->call_rcu(net, net->nfnl, skb, nlh,
219 (const struct nlattr **)cda,
220 extack);
221 rcu_read_unlock();
222 } else {
223 rcu_read_unlock();
224 nfnl_lock(subsys_id);
225 if (nfnl_dereference_protected(subsys_id) != ss ||
226 nfnetlink_find_client(type, ss) != nc)
227 err = -EAGAIN;
228 else if (nc->call)
229 err = nc->call(net, net->nfnl, skb, nlh,
230 (const struct nlattr **)cda,
231 extack);
232 else
233 err = -EINVAL;
234 nfnl_unlock(subsys_id);
235 }
236 if (err == -EAGAIN)
237 goto replay;
238 return err;
239 }
240 }
241
242 struct nfnl_err {
243 struct list_head head;
244 struct nlmsghdr *nlh;
245 int err;
246 struct netlink_ext_ack extack;
247 };
248
249 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
250 const struct netlink_ext_ack *extack)
251 {
252 struct nfnl_err *nfnl_err;
253
254 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
255 if (nfnl_err == NULL)
256 return -ENOMEM;
257
258 nfnl_err->nlh = nlh;
259 nfnl_err->err = err;
260 nfnl_err->extack = *extack;
261 list_add_tail(&nfnl_err->head, list);
262
263 return 0;
264 }
265
266 static void nfnl_err_del(struct nfnl_err *nfnl_err)
267 {
268 list_del(&nfnl_err->head);
269 kfree(nfnl_err);
270 }
271
272 static void nfnl_err_reset(struct list_head *err_list)
273 {
274 struct nfnl_err *nfnl_err, *next;
275
276 list_for_each_entry_safe(nfnl_err, next, err_list, head)
277 nfnl_err_del(nfnl_err);
278 }
279
280 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
281 {
282 struct nfnl_err *nfnl_err, *next;
283
284 list_for_each_entry_safe(nfnl_err, next, err_list, head) {
285 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
286 &nfnl_err->extack);
287 nfnl_err_del(nfnl_err);
288 }
289 }
290
291 enum {
292 NFNL_BATCH_FAILURE = (1 << 0),
293 NFNL_BATCH_DONE = (1 << 1),
294 NFNL_BATCH_REPLAY = (1 << 2),
295 };
296
297 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
298 u16 subsys_id, u32 genid)
299 {
300 struct sk_buff *oskb = skb;
301 struct net *net = sock_net(skb->sk);
302 const struct nfnetlink_subsystem *ss;
303 const struct nfnl_callback *nc;
304 struct netlink_ext_ack extack;
305 LIST_HEAD(err_list);
306 u32 status;
307 int err;
308
309 if (subsys_id >= NFNL_SUBSYS_COUNT)
310 return netlink_ack(skb, nlh, -EINVAL, NULL);
311 replay:
312 status = 0;
313
314 skb = netlink_skb_clone(oskb, GFP_KERNEL);
315 if (!skb)
316 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
317
318 nfnl_lock(subsys_id);
319 ss = nfnl_dereference_protected(subsys_id);
320 if (!ss) {
321 #ifdef CONFIG_MODULES
322 nfnl_unlock(subsys_id);
323 request_module("nfnetlink-subsys-%d", subsys_id);
324 nfnl_lock(subsys_id);
325 ss = nfnl_dereference_protected(subsys_id);
326 if (!ss)
327 #endif
328 {
329 nfnl_unlock(subsys_id);
330 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
331 return kfree_skb(skb);
332 }
333 }
334
335 if (!ss->valid_genid || !ss->commit || !ss->abort) {
336 nfnl_unlock(subsys_id);
337 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
338 return kfree_skb(skb);
339 }
340
341 if (!try_module_get(ss->owner)) {
342 nfnl_unlock(subsys_id);
343 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
344 return kfree_skb(skb);
345 }
346
347 if (!ss->valid_genid(net, genid)) {
348 module_put(ss->owner);
349 nfnl_unlock(subsys_id);
350 netlink_ack(oskb, nlh, -ERESTART, NULL);
351 return kfree_skb(skb);
352 }
353
354 nfnl_unlock(subsys_id);
355
356 while (skb->len >= nlmsg_total_size(0)) {
357 int msglen, type;
358
359 if (fatal_signal_pending(current)) {
360 nfnl_err_reset(&err_list);
361 err = -EINTR;
362 status = NFNL_BATCH_FAILURE;
363 goto done;
364 }
365
366 memset(&extack, 0, sizeof(extack));
367 nlh = nlmsg_hdr(skb);
368 err = 0;
369
370 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
371 skb->len < nlh->nlmsg_len ||
372 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
373 nfnl_err_reset(&err_list);
374 status |= NFNL_BATCH_FAILURE;
375 goto done;
376 }
377
378 /* Only requests are handled by the kernel */
379 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
380 err = -EINVAL;
381 goto ack;
382 }
383
384 type = nlh->nlmsg_type;
385 if (type == NFNL_MSG_BATCH_BEGIN) {
386 /* Malformed: Batch begin twice */
387 nfnl_err_reset(&err_list);
388 status |= NFNL_BATCH_FAILURE;
389 goto done;
390 } else if (type == NFNL_MSG_BATCH_END) {
391 status |= NFNL_BATCH_DONE;
392 goto done;
393 } else if (type < NLMSG_MIN_TYPE) {
394 err = -EINVAL;
395 goto ack;
396 }
397
398 /* We only accept a batch with messages for the same
399 * subsystem.
400 */
401 if (NFNL_SUBSYS_ID(type) != subsys_id) {
402 err = -EINVAL;
403 goto ack;
404 }
405
406 nc = nfnetlink_find_client(type, ss);
407 if (!nc) {
408 err = -EINVAL;
409 goto ack;
410 }
411
412 {
413 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
414 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
415 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
416 struct nlattr *attr = (void *)nlh + min_len;
417 int attrlen = nlh->nlmsg_len - min_len;
418
419 /* Sanity-check NFTA_MAX_ATTR */
420 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
421 err = -ENOMEM;
422 goto ack;
423 }
424
425 err = nla_parse_deprecated(cda,
426 ss->cb[cb_id].attr_count,
427 attr, attrlen,
428 ss->cb[cb_id].policy, NULL);
429 if (err < 0)
430 goto ack;
431
432 if (nc->call_batch) {
433 err = nc->call_batch(net, net->nfnl, skb, nlh,
434 (const struct nlattr **)cda,
435 &extack);
436 }
437
438 /* The lock was released to autoload some module, we
439 * have to abort and start from scratch using the
440 * original skb.
441 */
442 if (err == -EAGAIN) {
443 status |= NFNL_BATCH_REPLAY;
444 goto done;
445 }
446 }
447 ack:
448 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
449 /* Errors are delivered once the full batch has been
450 * processed, this avoids that the same error is
451 * reported several times when replaying the batch.
452 */
453 if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
454 /* We failed to enqueue an error, reset the
455 * list of errors and send OOM to userspace
456 * pointing to the batch header.
457 */
458 nfnl_err_reset(&err_list);
459 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
460 NULL);
461 status |= NFNL_BATCH_FAILURE;
462 goto done;
463 }
464 /* We don't stop processing the batch on errors, thus,
465 * userspace gets all the errors that the batch
466 * triggers.
467 */
468 if (err)
469 status |= NFNL_BATCH_FAILURE;
470 }
471
472 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
473 if (msglen > skb->len)
474 msglen = skb->len;
475 skb_pull(skb, msglen);
476 }
477 done:
478 if (status & NFNL_BATCH_REPLAY) {
479 ss->abort(net, oskb, true);
480 nfnl_err_reset(&err_list);
481 kfree_skb(skb);
482 module_put(ss->owner);
483 goto replay;
484 } else if (status == NFNL_BATCH_DONE) {
485 err = ss->commit(net, oskb);
486 if (err == -EAGAIN) {
487 status |= NFNL_BATCH_REPLAY;
488 goto done;
489 } else if (err) {
490 ss->abort(net, oskb, false);
491 netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
492 }
493 } else {
494 ss->abort(net, oskb, false);
495 }
496 if (ss->cleanup)
497 ss->cleanup(net);
498
499 nfnl_err_deliver(&err_list, oskb);
500 kfree_skb(skb);
501 module_put(ss->owner);
502 }
503
504 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
505 [NFNL_BATCH_GENID] = { .type = NLA_U32 },
506 };
507
508 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
509 {
510 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
511 struct nlattr *attr = (void *)nlh + min_len;
512 struct nlattr *cda[NFNL_BATCH_MAX + 1];
513 int attrlen = nlh->nlmsg_len - min_len;
514 struct nfgenmsg *nfgenmsg;
515 int msglen, err;
516 u32 gen_id = 0;
517 u16 res_id;
518
519 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
520 if (msglen > skb->len)
521 msglen = skb->len;
522
523 if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
524 return;
525
526 err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
527 nfnl_batch_policy, NULL);
528 if (err < 0) {
529 netlink_ack(skb, nlh, err, NULL);
530 return;
531 }
532 if (cda[NFNL_BATCH_GENID])
533 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
534
535 nfgenmsg = nlmsg_data(nlh);
536 skb_pull(skb, msglen);
537 /* Work around old nft using host byte order */
538 if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
539 res_id = NFNL_SUBSYS_NFTABLES;
540 else
541 res_id = ntohs(nfgenmsg->res_id);
542
543 nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
544 }
545
546 static void nfnetlink_rcv(struct sk_buff *skb)
547 {
548 struct nlmsghdr *nlh = nlmsg_hdr(skb);
549
550 if (skb->len < NLMSG_HDRLEN ||
551 nlh->nlmsg_len < NLMSG_HDRLEN ||
552 skb->len < nlh->nlmsg_len)
553 return;
554
555 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
556 netlink_ack(skb, nlh, -EPERM, NULL);
557 return;
558 }
559
560 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
561 nfnetlink_rcv_skb_batch(skb, nlh);
562 else
563 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
564 }
565
566 #ifdef CONFIG_MODULES
567 static int nfnetlink_bind(struct net *net, int group)
568 {
569 const struct nfnetlink_subsystem *ss;
570 int type;
571
572 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
573 return 0;
574
575 type = nfnl_group2type[group];
576
577 rcu_read_lock();
578 ss = nfnetlink_get_subsys(type << 8);
579 rcu_read_unlock();
580 if (!ss)
581 request_module_nowait("nfnetlink-subsys-%d", type);
582 return 0;
583 }
584 #endif
585
586 static int __net_init nfnetlink_net_init(struct net *net)
587 {
588 struct sock *nfnl;
589 struct netlink_kernel_cfg cfg = {
590 .groups = NFNLGRP_MAX,
591 .input = nfnetlink_rcv,
592 #ifdef CONFIG_MODULES
593 .bind = nfnetlink_bind,
594 #endif
595 };
596
597 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
598 if (!nfnl)
599 return -ENOMEM;
600 net->nfnl_stash = nfnl;
601 rcu_assign_pointer(net->nfnl, nfnl);
602 return 0;
603 }
604
605 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
606 {
607 struct net *net;
608
609 list_for_each_entry(net, net_exit_list, exit_list)
610 RCU_INIT_POINTER(net->nfnl, NULL);
611 synchronize_net();
612 list_for_each_entry(net, net_exit_list, exit_list)
613 netlink_kernel_release(net->nfnl_stash);
614 }
615
616 static struct pernet_operations nfnetlink_net_ops = {
617 .init = nfnetlink_net_init,
618 .exit_batch = nfnetlink_net_exit_batch,
619 };
620
621 static int __init nfnetlink_init(void)
622 {
623 int i;
624
625 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
626 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
627
628 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
629 mutex_init(&table[i].mutex);
630
631 return register_pernet_subsys(&nfnetlink_net_ops);
632 }
633
634 static void __exit nfnetlink_exit(void)
635 {
636 unregister_pernet_subsys(&nfnetlink_net_ops);
637 }
638 module_init(nfnetlink_init);
639 module_exit(nfnetlink_exit);
Linux with added FPC-III support