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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
29#include <net/netlink.h>
30#include <linux/netfilter/nfnetlink.h>
31
32MODULE_LICENSE("GPL");
33MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
34MODULE_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
40static char __initdata nfversion[] = "0.30";
41
42static struct {
43 struct mutex mutex;
44 const struct nfnetlink_subsystem __rcu *subsys;
45} table[NFNL_SUBSYS_COUNT];
46
47static 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
59void nfnl_lock(__u8 subsys_id)
60{
61 mutex_lock(&table[subsys_id].mutex);
62}
63EXPORT_SYMBOL_GPL(nfnl_lock);
64
65void nfnl_unlock(__u8 subsys_id)
66{
67 mutex_unlock(&table[subsys_id].mutex);
68}
69EXPORT_SYMBOL_GPL(nfnl_unlock);
70
71#ifdef CONFIG_PROVE_LOCKING
72bool lockdep_nfnl_is_held(u8 subsys_id)
73{
74 return lockdep_is_held(&table[subsys_id].mutex);
75}
76EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
77#endif
78
79int 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}
91EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
92
93int 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}
101EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
102
103static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
104{
105 u8 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
113static inline const struct nfnl_callback *
114nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
115{
116 u8 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
124int nfnetlink_has_listeners(struct net *net, unsigned int group)
125{
126 return netlink_has_listeners(net->nfnl, group);
127}
128EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
129
130int 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}
135EXPORT_SYMBOL_GPL(nfnetlink_send);
136
137int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
138{
139 return netlink_set_err(net->nfnl, portid, group, error);
140}
141EXPORT_SYMBOL_GPL(nfnetlink_set_err);
142
143int 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}
148EXPORT_SYMBOL_GPL(nfnetlink_unicast);
149
150
151static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
152 struct netlink_ext_ack *extack)
153{
154 struct net *net = sock_net(skb->sk);
155 const struct nfnl_callback *nc;
156 const struct nfnetlink_subsystem *ss;
157 int type, err;
158
159
160 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
161 return 0;
162
163 type = nlh->nlmsg_type;
164replay:
165 rcu_read_lock();
166 ss = nfnetlink_get_subsys(type);
167 if (!ss) {
168#ifdef CONFIG_MODULES
169 rcu_read_unlock();
170 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
171 rcu_read_lock();
172 ss = nfnetlink_get_subsys(type);
173 if (!ss)
174#endif
175 {
176 rcu_read_unlock();
177 return -EINVAL;
178 }
179 }
180
181 nc = nfnetlink_find_client(type, ss);
182 if (!nc) {
183 rcu_read_unlock();
184 return -EINVAL;
185 }
186
187 {
188 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
189 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
190 struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
191 struct nlattr *attr = (void *)nlh + min_len;
192 int attrlen = nlh->nlmsg_len - min_len;
193 __u8 subsys_id = NFNL_SUBSYS_ID(type);
194
195 err = nla_parse(cda, ss->cb[cb_id].attr_count, attr, attrlen,
196 ss->cb[cb_id].policy, extack);
197 if (err < 0) {
198 rcu_read_unlock();
199 return err;
200 }
201
202 if (nc->call_rcu) {
203 err = nc->call_rcu(net, net->nfnl, skb, nlh,
204 (const struct nlattr **)cda,
205 extack);
206 rcu_read_unlock();
207 } else {
208 rcu_read_unlock();
209 nfnl_lock(subsys_id);
210 if (nfnl_dereference_protected(subsys_id) != ss ||
211 nfnetlink_find_client(type, ss) != nc)
212 err = -EAGAIN;
213 else if (nc->call)
214 err = nc->call(net, net->nfnl, skb, nlh,
215 (const struct nlattr **)cda,
216 extack);
217 else
218 err = -EINVAL;
219 nfnl_unlock(subsys_id);
220 }
221 if (err == -EAGAIN)
222 goto replay;
223 return err;
224 }
225}
226
227struct nfnl_err {
228 struct list_head head;
229 struct nlmsghdr *nlh;
230 int err;
231 struct netlink_ext_ack extack;
232};
233
234static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
235 const struct netlink_ext_ack *extack)
236{
237 struct nfnl_err *nfnl_err;
238
239 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
240 if (nfnl_err == NULL)
241 return -ENOMEM;
242
243 nfnl_err->nlh = nlh;
244 nfnl_err->err = err;
245 nfnl_err->extack = *extack;
246 list_add_tail(&nfnl_err->head, list);
247
248 return 0;
249}
250
251static void nfnl_err_del(struct nfnl_err *nfnl_err)
252{
253 list_del(&nfnl_err->head);
254 kfree(nfnl_err);
255}
256
257static void nfnl_err_reset(struct list_head *err_list)
258{
259 struct nfnl_err *nfnl_err, *next;
260
261 list_for_each_entry_safe(nfnl_err, next, err_list, head)
262 nfnl_err_del(nfnl_err);
263}
264
265static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
266{
267 struct nfnl_err *nfnl_err, *next;
268
269 list_for_each_entry_safe(nfnl_err, next, err_list, head) {
270 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
271 &nfnl_err->extack);
272 nfnl_err_del(nfnl_err);
273 }
274}
275
276enum {
277 NFNL_BATCH_FAILURE = (1 << 0),
278 NFNL_BATCH_DONE = (1 << 1),
279 NFNL_BATCH_REPLAY = (1 << 2),
280};
281
282static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
283 u16 subsys_id, u32 genid)
284{
285 struct sk_buff *oskb = skb;
286 struct net *net = sock_net(skb->sk);
287 const struct nfnetlink_subsystem *ss;
288 const struct nfnl_callback *nc;
289 struct netlink_ext_ack extack;
290 LIST_HEAD(err_list);
291 u32 status;
292 int err;
293
294 if (subsys_id >= NFNL_SUBSYS_COUNT)
295 return netlink_ack(skb, nlh, -EINVAL, NULL);
296replay:
297 status = 0;
298
299 skb = netlink_skb_clone(oskb, GFP_KERNEL);
300 if (!skb)
301 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
302
303 nfnl_lock(subsys_id);
304 ss = nfnl_dereference_protected(subsys_id);
305 if (!ss) {
306#ifdef CONFIG_MODULES
307 nfnl_unlock(subsys_id);
308 request_module("nfnetlink-subsys-%d", subsys_id);
309 nfnl_lock(subsys_id);
310 ss = nfnl_dereference_protected(subsys_id);
311 if (!ss)
312#endif
313 {
314 nfnl_unlock(subsys_id);
315 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
316 return kfree_skb(skb);
317 }
318 }
319
320 if (!ss->commit || !ss->abort) {
321 nfnl_unlock(subsys_id);
322 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
323 return kfree_skb(skb);
324 }
325
326 if (genid && ss->valid_genid && !ss->valid_genid(net, genid)) {
327 nfnl_unlock(subsys_id);
328 netlink_ack(oskb, nlh, -ERESTART, NULL);
329 return kfree_skb(skb);
330 }
331
332 while (skb->len >= nlmsg_total_size(0)) {
333 int msglen, type;
334
335 memset(&extack, 0, sizeof(extack));
336 nlh = nlmsg_hdr(skb);
337 err = 0;
338
339 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
340 skb->len < nlh->nlmsg_len ||
341 nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
342 nfnl_err_reset(&err_list);
343 status |= NFNL_BATCH_FAILURE;
344 goto done;
345 }
346
347
348 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
349 err = -EINVAL;
350 goto ack;
351 }
352
353 type = nlh->nlmsg_type;
354 if (type == NFNL_MSG_BATCH_BEGIN) {
355
356 nfnl_err_reset(&err_list);
357 status |= NFNL_BATCH_FAILURE;
358 goto done;
359 } else if (type == NFNL_MSG_BATCH_END) {
360 status |= NFNL_BATCH_DONE;
361 goto done;
362 } else if (type < NLMSG_MIN_TYPE) {
363 err = -EINVAL;
364 goto ack;
365 }
366
367
368
369
370 if (NFNL_SUBSYS_ID(type) != subsys_id) {
371 err = -EINVAL;
372 goto ack;
373 }
374
375 nc = nfnetlink_find_client(type, ss);
376 if (!nc) {
377 err = -EINVAL;
378 goto ack;
379 }
380
381 {
382 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
383 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
384 struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
385 struct nlattr *attr = (void *)nlh + min_len;
386 int attrlen = nlh->nlmsg_len - min_len;
387
388 err = nla_parse(cda, ss->cb[cb_id].attr_count, attr,
389 attrlen, ss->cb[cb_id].policy, NULL);
390 if (err < 0)
391 goto ack;
392
393 if (nc->call_batch) {
394 err = nc->call_batch(net, net->nfnl, skb, nlh,
395 (const struct nlattr **)cda,
396 &extack);
397 }
398
399
400
401
402
403 if (err == -EAGAIN) {
404 status |= NFNL_BATCH_REPLAY;
405 goto next;
406 }
407 }
408ack:
409 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
410
411
412
413
414 if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
415
416
417
418
419 nfnl_err_reset(&err_list);
420 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
421 NULL);
422 status |= NFNL_BATCH_FAILURE;
423 goto done;
424 }
425
426
427
428
429 if (err)
430 status |= NFNL_BATCH_FAILURE;
431 }
432next:
433 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
434 if (msglen > skb->len)
435 msglen = skb->len;
436 skb_pull(skb, msglen);
437 }
438done:
439 if (status & NFNL_BATCH_REPLAY) {
440 ss->abort(net, oskb);
441 nfnl_err_reset(&err_list);
442 nfnl_unlock(subsys_id);
443 kfree_skb(skb);
444 goto replay;
445 } else if (status == NFNL_BATCH_DONE) {
446 ss->commit(net, oskb);
447 } else {
448 ss->abort(net, oskb);
449 }
450
451 nfnl_err_deliver(&err_list, oskb);
452 nfnl_unlock(subsys_id);
453 kfree_skb(skb);
454}
455
456static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
457 [NFNL_BATCH_GENID] = { .type = NLA_U32 },
458};
459
460static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
461{
462 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
463 struct nlattr *attr = (void *)nlh + min_len;
464 struct nlattr *cda[NFNL_BATCH_MAX + 1];
465 int attrlen = nlh->nlmsg_len - min_len;
466 struct nfgenmsg *nfgenmsg;
467 int msglen, err;
468 u32 gen_id = 0;
469 u16 res_id;
470
471 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
472 if (msglen > skb->len)
473 msglen = skb->len;
474
475 if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
476 return;
477
478 err = nla_parse(cda, NFNL_BATCH_MAX, attr, attrlen, nfnl_batch_policy,
479 NULL);
480 if (err < 0) {
481 netlink_ack(skb, nlh, err, NULL);
482 return;
483 }
484 if (cda[NFNL_BATCH_GENID])
485 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
486
487 nfgenmsg = nlmsg_data(nlh);
488 skb_pull(skb, msglen);
489
490 if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
491 res_id = NFNL_SUBSYS_NFTABLES;
492 else
493 res_id = ntohs(nfgenmsg->res_id);
494
495 nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
496}
497
498static void nfnetlink_rcv(struct sk_buff *skb)
499{
500 struct nlmsghdr *nlh = nlmsg_hdr(skb);
501
502 if (skb->len < NLMSG_HDRLEN ||
503 nlh->nlmsg_len < NLMSG_HDRLEN ||
504 skb->len < nlh->nlmsg_len)
505 return;
506
507 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
508 netlink_ack(skb, nlh, -EPERM, NULL);
509 return;
510 }
511
512 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
513 nfnetlink_rcv_skb_batch(skb, nlh);
514 else
515 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
516}
517
518#ifdef CONFIG_MODULES
519static int nfnetlink_bind(struct net *net, int group)
520{
521 const struct nfnetlink_subsystem *ss;
522 int type;
523
524 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
525 return 0;
526
527 type = nfnl_group2type[group];
528
529 rcu_read_lock();
530 ss = nfnetlink_get_subsys(type << 8);
531 rcu_read_unlock();
532 if (!ss)
533 request_module("nfnetlink-subsys-%d", type);
534 return 0;
535}
536#endif
537
538static int __net_init nfnetlink_net_init(struct net *net)
539{
540 struct sock *nfnl;
541 struct netlink_kernel_cfg cfg = {
542 .groups = NFNLGRP_MAX,
543 .input = nfnetlink_rcv,
544#ifdef CONFIG_MODULES
545 .bind = nfnetlink_bind,
546#endif
547 };
548
549 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
550 if (!nfnl)
551 return -ENOMEM;
552 net->nfnl_stash = nfnl;
553 rcu_assign_pointer(net->nfnl, nfnl);
554 return 0;
555}
556
557static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
558{
559 struct net *net;
560
561 list_for_each_entry(net, net_exit_list, exit_list)
562 RCU_INIT_POINTER(net->nfnl, NULL);
563 synchronize_net();
564 list_for_each_entry(net, net_exit_list, exit_list)
565 netlink_kernel_release(net->nfnl_stash);
566}
567
568static struct pernet_operations nfnetlink_net_ops = {
569 .init = nfnetlink_net_init,
570 .exit_batch = nfnetlink_net_exit_batch,
571};
572
573static int __init nfnetlink_init(void)
574{
575 int i;
576
577 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
578 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
579
580 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
581 mutex_init(&table[i].mutex);
582
583 pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
584 return register_pernet_subsys(&nfnetlink_net_ops);
585}
586
587static void __exit nfnetlink_exit(void)
588{
589 pr_info("Removing netfilter NETLINK layer.\n");
590 unregister_pernet_subsys(&nfnetlink_net_ops);
591}
592module_init(nfnetlink_init);
593module_exit(nfnetlink_exit);
594
