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btrfs: fix one bug that process may endlessly wait for ticket in wait_reserve_ticket()
[linux/fpc-iii.git] / net / netfilter / nfnetlink.c
blob2278d9ab723bf1c3a2b199db6fc9519e9c59e1be
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) 2005,2007 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 <asm/uaccess.h>
26 #include <net/sock.h>
27 #include <linux/init.h>
28
29 #include <net/netlink.h>
30 #include <linux/netfilter/nfnetlink.h>
31
32 MODULE_LICENSE("GPL");
33 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
34 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
35
36 #define nfnl_dereference_protected(id) \
37 rcu_dereference_protected(table[(id)].subsys, \
38 lockdep_nfnl_is_held((id)))
39
40 static char __initdata nfversion[] = "0.30";
41
42 static struct {
43 struct mutex mutex;
44 const struct nfnetlink_subsystem __rcu *subsys;
45 } table[NFNL_SUBSYS_COUNT];
46
47 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
48 [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
49 [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK,
50 [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK,
51 [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
52 [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
53 [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
54 [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES,
55 [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT,
56 [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES,
57 };
58
59 void nfnl_lock(__u8 subsys_id)
60 {
61 mutex_lock(&table[subsys_id].mutex);
62 }
63 EXPORT_SYMBOL_GPL(nfnl_lock);
64
65 void nfnl_unlock(__u8 subsys_id)
66 {
67 mutex_unlock(&table[subsys_id].mutex);
68 }
69 EXPORT_SYMBOL_GPL(nfnl_unlock);
70
71 #ifdef CONFIG_PROVE_LOCKING
72 bool lockdep_nfnl_is_held(u8 subsys_id)
73 {
74 return lockdep_is_held(&table[subsys_id].mutex);
75 }
76 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
77 #endif
78
79 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
80 {
81 nfnl_lock(n->subsys_id);
82 if (table[n->subsys_id].subsys) {
83 nfnl_unlock(n->subsys_id);
84 return -EBUSY;
85 }
86 rcu_assign_pointer(table[n->subsys_id].subsys, n);
87 nfnl_unlock(n->subsys_id);
88
89 return 0;
90 }
91 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
92
93 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
94 {
95 nfnl_lock(n->subsys_id);
96 table[n->subsys_id].subsys = NULL;
97 nfnl_unlock(n->subsys_id);
98 synchronize_rcu();
99 return 0;
100 }
101 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
102
103 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
104 {
105 u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
106
107 if (subsys_id >= NFNL_SUBSYS_COUNT)
108 return NULL;
109
110 return rcu_dereference(table[subsys_id].subsys);
111 }
112
113 static inline const struct nfnl_callback *
114 nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
115 {
116 u_int8_t cb_id = NFNL_MSG_TYPE(type);
117
118 if (cb_id >= ss->cb_count)
119 return NULL;
120
121 return &ss->cb[cb_id];
122 }
123
124 int nfnetlink_has_listeners(struct net *net, unsigned int group)
125 {
126 return netlink_has_listeners(net->nfnl, group);
127 }
128 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
129
130 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
131 unsigned int group, int echo, gfp_t flags)
132 {
133 return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags);
134 }
135 EXPORT_SYMBOL_GPL(nfnetlink_send);
136
137 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
138 {
139 return netlink_set_err(net->nfnl, portid, group, error);
140 }
141 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
142
143 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid,
144 int flags)
145 {
146 return netlink_unicast(net->nfnl, skb, portid, flags);
147 }
148 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
149
150 /* Process one complete nfnetlink message. */
151 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
152 {
153 struct net *net = sock_net(skb->sk);
154 const struct nfnl_callback *nc;
155 const struct nfnetlink_subsystem *ss;
156 int type, err;
157
158 /* All the messages must at least contain nfgenmsg */
159 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
160 return 0;
161
162 type = nlh->nlmsg_type;
163 replay:
164 rcu_read_lock();
165 ss = nfnetlink_get_subsys(type);
166 if (!ss) {
167 #ifdef CONFIG_MODULES
168 rcu_read_unlock();
169 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
170 rcu_read_lock();
171 ss = nfnetlink_get_subsys(type);
172 if (!ss)
173 #endif
174 {
175 rcu_read_unlock();
176 return -EINVAL;
177 }
178 }
179
180 nc = nfnetlink_find_client(type, ss);
181 if (!nc) {
182 rcu_read_unlock();
183 return -EINVAL;
184 }
185
186 {
187 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
188 u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
189 struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
190 struct nlattr *attr = (void *)nlh + min_len;
191 int attrlen = nlh->nlmsg_len - min_len;
192 __u8 subsys_id = NFNL_SUBSYS_ID(type);
193
194 err = nla_parse(cda, ss->cb[cb_id].attr_count,
195 attr, attrlen, ss->cb[cb_id].policy);
196 if (err < 0) {
197 rcu_read_unlock();
198 return err;
199 }
200
201 if (nc->call_rcu) {
202 err = nc->call_rcu(net, net->nfnl, skb, nlh,
203 (const struct nlattr **)cda);
204 rcu_read_unlock();
205 } else {
206 rcu_read_unlock();
207 nfnl_lock(subsys_id);
208 if (nfnl_dereference_protected(subsys_id) != ss ||
209 nfnetlink_find_client(type, ss) != nc)
210 err = -EAGAIN;
211 else if (nc->call)
212 err = nc->call(net, net->nfnl, skb, nlh,
213 (const struct nlattr **)cda);
214 else
215 err = -EINVAL;
216 nfnl_unlock(subsys_id);
217 }
218 if (err == -EAGAIN)
219 goto replay;
220 return err;
221 }
222 }
223
224 struct nfnl_err {
225 struct list_head head;
226 struct nlmsghdr *nlh;
227 int err;
228 };
229
230 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err)
231 {
232 struct nfnl_err *nfnl_err;
233
234 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
235 if (nfnl_err == NULL)
236 return -ENOMEM;
237
238 nfnl_err->nlh = nlh;
239 nfnl_err->err = err;
240 list_add_tail(&nfnl_err->head, list);
241
242 return 0;
243 }
244
245 static void nfnl_err_del(struct nfnl_err *nfnl_err)
246 {
247 list_del(&nfnl_err->head);
248 kfree(nfnl_err);
249 }
250
251 static void nfnl_err_reset(struct list_head *err_list)
252 {
253 struct nfnl_err *nfnl_err, *next;
254
255 list_for_each_entry_safe(nfnl_err, next, err_list, head)
256 nfnl_err_del(nfnl_err);
257 }
258
259 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
260 {
261 struct nfnl_err *nfnl_err, *next;
262
263 list_for_each_entry_safe(nfnl_err, next, err_list, head) {
264 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err);
265 nfnl_err_del(nfnl_err);
266 }
267 }
268
269 enum {
270 NFNL_BATCH_FAILURE = (1 << 0),
271 NFNL_BATCH_DONE = (1 << 1),
272 NFNL_BATCH_REPLAY = (1 << 2),
273 };
274
275 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
276 u_int16_t subsys_id)
277 {
278 struct sk_buff *oskb = skb;
279 struct net *net = sock_net(skb->sk);
280 const struct nfnetlink_subsystem *ss;
281 const struct nfnl_callback *nc;
282 static LIST_HEAD(err_list);
283 u32 status;
284 int err;
285
286 if (subsys_id >= NFNL_SUBSYS_COUNT)
287 return netlink_ack(skb, nlh, -EINVAL);
288 replay:
289 status = 0;
290
291 skb = netlink_skb_clone(oskb, GFP_KERNEL);
292 if (!skb)
293 return netlink_ack(oskb, nlh, -ENOMEM);
294
295 nfnl_lock(subsys_id);
296 ss = nfnl_dereference_protected(subsys_id);
297 if (!ss) {
298 #ifdef CONFIG_MODULES
299 nfnl_unlock(subsys_id);
300 request_module("nfnetlink-subsys-%d", subsys_id);
301 nfnl_lock(subsys_id);
302 ss = nfnl_dereference_protected(subsys_id);
303 if (!ss)
304 #endif
305 {
306 nfnl_unlock(subsys_id);
307 netlink_ack(oskb, nlh, -EOPNOTSUPP);
308 return kfree_skb(skb);
309 }
310 }
311
312 if (!ss->commit || !ss->abort) {
313 nfnl_unlock(subsys_id);
314 netlink_ack(oskb, nlh, -EOPNOTSUPP);
315 return kfree_skb(skb);
316 }
317
318 while (skb->len >= nlmsg_total_size(0)) {
319 int msglen, type;
320
321 nlh = nlmsg_hdr(skb);
322 err = 0;
323
324 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
325 skb->len < nlh->nlmsg_len ||
326 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
327 nfnl_err_reset(&err_list);
328 status |= NFNL_BATCH_FAILURE;
329 goto done;
330 }
331
332 /* Only requests are handled by the kernel */
333 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
334 err = -EINVAL;
335 goto ack;
336 }
337
338 type = nlh->nlmsg_type;
339 if (type == NFNL_MSG_BATCH_BEGIN) {
340 /* Malformed: Batch begin twice */
341 nfnl_err_reset(&err_list);
342 status |= NFNL_BATCH_FAILURE;
343 goto done;
344 } else if (type == NFNL_MSG_BATCH_END) {
345 status |= NFNL_BATCH_DONE;
346 goto done;
347 } else if (type < NLMSG_MIN_TYPE) {
348 err = -EINVAL;
349 goto ack;
350 }
351
352 /* We only accept a batch with messages for the same
353 * subsystem.
354 */
355 if (NFNL_SUBSYS_ID(type) != subsys_id) {
356 err = -EINVAL;
357 goto ack;
358 }
359
360 nc = nfnetlink_find_client(type, ss);
361 if (!nc) {
362 err = -EINVAL;
363 goto ack;
364 }
365
366 {
367 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
368 u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
369 struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
370 struct nlattr *attr = (void *)nlh + min_len;
371 int attrlen = nlh->nlmsg_len - min_len;
372
373 err = nla_parse(cda, ss->cb[cb_id].attr_count,
374 attr, attrlen, ss->cb[cb_id].policy);
375 if (err < 0)
376 goto ack;
377
378 if (nc->call_batch) {
379 err = nc->call_batch(net, net->nfnl, skb, nlh,
380 (const struct nlattr **)cda);
381 }
382
383 /* The lock was released to autoload some module, we
384 * have to abort and start from scratch using the
385 * original skb.
386 */
387 if (err == -EAGAIN) {
388 status |= NFNL_BATCH_REPLAY;
389 goto next;
390 }
391 }
392 ack:
393 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
394 /* Errors are delivered once the full batch has been
395 * processed, this avoids that the same error is
396 * reported several times when replaying the batch.
397 */
398 if (nfnl_err_add(&err_list, nlh, err) < 0) {
399 /* We failed to enqueue an error, reset the
400 * list of errors and send OOM to userspace
401 * pointing to the batch header.
402 */
403 nfnl_err_reset(&err_list);
404 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM);
405 status |= NFNL_BATCH_FAILURE;
406 goto done;
407 }
408 /* We don't stop processing the batch on errors, thus,
409 * userspace gets all the errors that the batch
410 * triggers.
411 */
412 if (err)
413 status |= NFNL_BATCH_FAILURE;
414 }
415 next:
416 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
417 if (msglen > skb->len)
418 msglen = skb->len;
419 skb_pull(skb, msglen);
420 }
421 done:
422 if (status & NFNL_BATCH_REPLAY) {
423 ss->abort(net, oskb);
424 nfnl_err_reset(&err_list);
425 nfnl_unlock(subsys_id);
426 kfree_skb(skb);
427 goto replay;
428 } else if (status == NFNL_BATCH_DONE) {
429 ss->commit(net, oskb);
430 } else {
431 ss->abort(net, oskb);
432 }
433
434 nfnl_err_deliver(&err_list, oskb);
435 nfnl_unlock(subsys_id);
436 kfree_skb(skb);
437 }
438
439 static void nfnetlink_rcv(struct sk_buff *skb)
440 {
441 struct nlmsghdr *nlh = nlmsg_hdr(skb);
442 u_int16_t res_id;
443 int msglen;
444
445 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
446 skb->len < nlh->nlmsg_len)
447 return;
448
449 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
450 netlink_ack(skb, nlh, -EPERM);
451 return;
452 }
453
454 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) {
455 struct nfgenmsg *nfgenmsg;
456
457 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
458 if (msglen > skb->len)
459 msglen = skb->len;
460
461 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
462 skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
463 return;
464
465 nfgenmsg = nlmsg_data(nlh);
466 skb_pull(skb, msglen);
467 /* Work around old nft using host byte order */
468 if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
469 res_id = NFNL_SUBSYS_NFTABLES;
470 else
471 res_id = ntohs(nfgenmsg->res_id);
472 nfnetlink_rcv_batch(skb, nlh, res_id);
473 } else {
474 netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
475 }
476 }
477
478 #ifdef CONFIG_MODULES
479 static int nfnetlink_bind(struct net *net, int group)
480 {
481 const struct nfnetlink_subsystem *ss;
482 int type;
483
484 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
485 return 0;
486
487 type = nfnl_group2type[group];
488
489 rcu_read_lock();
490 ss = nfnetlink_get_subsys(type << 8);
491 rcu_read_unlock();
492 if (!ss)
493 request_module("nfnetlink-subsys-%d", type);
494 return 0;
495 }
496 #endif
497
498 static int __net_init nfnetlink_net_init(struct net *net)
499 {
500 struct sock *nfnl;
501 struct netlink_kernel_cfg cfg = {
502 .groups = NFNLGRP_MAX,
503 .input = nfnetlink_rcv,
504 #ifdef CONFIG_MODULES
505 .bind = nfnetlink_bind,
506 #endif
507 };
508
509 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
510 if (!nfnl)
511 return -ENOMEM;
512 net->nfnl_stash = nfnl;
513 rcu_assign_pointer(net->nfnl, nfnl);
514 return 0;
515 }
516
517 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
518 {
519 struct net *net;
520
521 list_for_each_entry(net, net_exit_list, exit_list)
522 RCU_INIT_POINTER(net->nfnl, NULL);
523 synchronize_net();
524 list_for_each_entry(net, net_exit_list, exit_list)
525 netlink_kernel_release(net->nfnl_stash);
526 }
527
528 static struct pernet_operations nfnetlink_net_ops = {
529 .init = nfnetlink_net_init,
530 .exit_batch = nfnetlink_net_exit_batch,
531 };
532
533 static int __init nfnetlink_init(void)
534 {
535 int i;
536
537 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
538 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
539
540 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
541 mutex_init(&table[i].mutex);
542
543 pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
544 return register_pernet_subsys(&nfnetlink_net_ops);
545 }
546
547 static void __exit nfnetlink_exit(void)
548 {
549 pr_info("Removing netfilter NETLINK layer.\n");
550 unregister_pernet_subsys(&nfnetlink_net_ops);
551 }
552 module_init(nfnetlink_init);
553 module_exit(nfnetlink_exit);
Linux with added FPC-III support