Commit | Line | Data |
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f9e815b3 HW |
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> | |
67ca3966 | 6 | * (C) 2005,2007 by Pablo Neira Ayuso <pablo@netfilter.org> |
f9e815b3 HW |
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 | ||
f9e815b3 HW |
17 | #include <linux/module.h> |
18 | #include <linux/types.h> | |
19 | #include <linux/socket.h> | |
20 | #include <linux/kernel.h> | |
f9e815b3 HW |
21 | #include <linux/string.h> |
22 | #include <linux/sockios.h> | |
23 | #include <linux/net.h> | |
f9e815b3 HW |
24 | #include <linux/skbuff.h> |
25 | #include <asm/uaccess.h> | |
f9e815b3 HW |
26 | #include <net/sock.h> |
27 | #include <linux/init.h> | |
f9e815b3 | 28 | |
573ce260 | 29 | #include <net/netlink.h> |
f9e815b3 HW |
30 | #include <linux/netfilter/nfnetlink.h> |
31 | ||
32 | MODULE_LICENSE("GPL"); | |
4fdb3bb7 HW |
33 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
34 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); | |
f9e815b3 HW |
35 | |
36 | static char __initdata nfversion[] = "0.30"; | |
37 | ||
c14b78e7 PNA |
38 | static struct { |
39 | struct mutex mutex; | |
40 | const struct nfnetlink_subsystem __rcu *subsys; | |
41 | } table[NFNL_SUBSYS_COUNT]; | |
f9e815b3 | 42 | |
03292745 PNA |
43 | static const int nfnl_group2type[NFNLGRP_MAX+1] = { |
44 | [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK, | |
45 | [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK, | |
46 | [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK, | |
47 | [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP, | |
48 | [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP, | |
49 | [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP, | |
50 | }; | |
51 | ||
c14b78e7 | 52 | void nfnl_lock(__u8 subsys_id) |
f9e815b3 | 53 | { |
c14b78e7 | 54 | mutex_lock(&table[subsys_id].mutex); |
f9e815b3 | 55 | } |
e6a7d3c0 | 56 | EXPORT_SYMBOL_GPL(nfnl_lock); |
f9e815b3 | 57 | |
c14b78e7 | 58 | void nfnl_unlock(__u8 subsys_id) |
a3c5029c | 59 | { |
c14b78e7 | 60 | mutex_unlock(&table[subsys_id].mutex); |
f9e815b3 | 61 | } |
e6a7d3c0 | 62 | EXPORT_SYMBOL_GPL(nfnl_unlock); |
f9e815b3 | 63 | |
7c8d4cb4 | 64 | int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
f9e815b3 | 65 | { |
c14b78e7 PNA |
66 | nfnl_lock(n->subsys_id); |
67 | if (table[n->subsys_id].subsys) { | |
68 | nfnl_unlock(n->subsys_id); | |
0ab43f84 HW |
69 | return -EBUSY; |
70 | } | |
c14b78e7 PNA |
71 | rcu_assign_pointer(table[n->subsys_id].subsys, n); |
72 | nfnl_unlock(n->subsys_id); | |
f9e815b3 HW |
73 | |
74 | return 0; | |
75 | } | |
f4bc177f | 76 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
f9e815b3 | 77 | |
7c8d4cb4 | 78 | int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
f9e815b3 | 79 | { |
c14b78e7 PNA |
80 | nfnl_lock(n->subsys_id); |
81 | table[n->subsys_id].subsys = NULL; | |
82 | nfnl_unlock(n->subsys_id); | |
6b75e3e8 | 83 | synchronize_rcu(); |
f9e815b3 HW |
84 | return 0; |
85 | } | |
f4bc177f | 86 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
f9e815b3 | 87 | |
7c8d4cb4 | 88 | static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) |
f9e815b3 HW |
89 | { |
90 | u_int8_t subsys_id = NFNL_SUBSYS_ID(type); | |
91 | ||
ac0f1d98 | 92 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
f9e815b3 HW |
93 | return NULL; |
94 | ||
c14b78e7 | 95 | return rcu_dereference(table[subsys_id].subsys); |
f9e815b3 HW |
96 | } |
97 | ||
7c8d4cb4 PM |
98 | static inline const struct nfnl_callback * |
99 | nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss) | |
f9e815b3 HW |
100 | { |
101 | u_int8_t cb_id = NFNL_MSG_TYPE(type); | |
601e68e1 | 102 | |
67ca3966 | 103 | if (cb_id >= ss->cb_count) |
f9e815b3 | 104 | return NULL; |
f9e815b3 HW |
105 | |
106 | return &ss->cb[cb_id]; | |
107 | } | |
108 | ||
cd8c20b6 | 109 | int nfnetlink_has_listeners(struct net *net, unsigned int group) |
a2427692 | 110 | { |
cd8c20b6 | 111 | return netlink_has_listeners(net->nfnl, group); |
a2427692 PM |
112 | } |
113 | EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); | |
114 | ||
3ab1f683 PM |
115 | struct sk_buff *nfnetlink_alloc_skb(struct net *net, unsigned int size, |
116 | u32 dst_portid, gfp_t gfp_mask) | |
117 | { | |
118 | return netlink_alloc_skb(net->nfnl, size, dst_portid, gfp_mask); | |
119 | } | |
120 | EXPORT_SYMBOL_GPL(nfnetlink_alloc_skb); | |
121 | ||
ec464e5d | 122 | int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid, |
95c96174 | 123 | unsigned int group, int echo, gfp_t flags) |
f9e815b3 | 124 | { |
ec464e5d | 125 | return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags); |
f9e815b3 | 126 | } |
f4bc177f | 127 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
f9e815b3 | 128 | |
ec464e5d | 129 | int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error) |
dd5b6ce6 | 130 | { |
ec464e5d | 131 | return netlink_set_err(net->nfnl, portid, group, error); |
dd5b6ce6 PNA |
132 | } |
133 | EXPORT_SYMBOL_GPL(nfnetlink_set_err); | |
134 | ||
ec464e5d PM |
135 | int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid, |
136 | int flags) | |
f9e815b3 | 137 | { |
ec464e5d | 138 | return netlink_unicast(net->nfnl, skb, portid, flags); |
f9e815b3 | 139 | } |
f4bc177f | 140 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
f9e815b3 HW |
141 | |
142 | /* Process one complete nfnetlink message. */ | |
1d00a4eb | 143 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
f9e815b3 | 144 | { |
cd8c20b6 | 145 | struct net *net = sock_net(skb->sk); |
7c8d4cb4 PM |
146 | const struct nfnl_callback *nc; |
147 | const struct nfnetlink_subsystem *ss; | |
1d00a4eb | 148 | int type, err; |
f9e815b3 | 149 | |
f9e815b3 | 150 | /* All the messages must at least contain nfgenmsg */ |
573ce260 | 151 | if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) |
f9e815b3 | 152 | return 0; |
f9e815b3 HW |
153 | |
154 | type = nlh->nlmsg_type; | |
e6a7d3c0 | 155 | replay: |
6b75e3e8 | 156 | rcu_read_lock(); |
f9e815b3 | 157 | ss = nfnetlink_get_subsys(type); |
0ab43f84 | 158 | if (!ss) { |
95a5afca | 159 | #ifdef CONFIG_MODULES |
6b75e3e8 | 160 | rcu_read_unlock(); |
37d2e7a2 | 161 | request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
6b75e3e8 | 162 | rcu_read_lock(); |
37d2e7a2 | 163 | ss = nfnetlink_get_subsys(type); |
0ab43f84 HW |
164 | if (!ss) |
165 | #endif | |
6b75e3e8 ED |
166 | { |
167 | rcu_read_unlock(); | |
1d00a4eb | 168 | return -EINVAL; |
6b75e3e8 | 169 | } |
0ab43f84 | 170 | } |
f9e815b3 HW |
171 | |
172 | nc = nfnetlink_find_client(type, ss); | |
6b75e3e8 ED |
173 | if (!nc) { |
174 | rcu_read_unlock(); | |
1d00a4eb | 175 | return -EINVAL; |
6b75e3e8 | 176 | } |
f9e815b3 | 177 | |
f9e815b3 | 178 | { |
573ce260 | 179 | int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); |
e3730578 | 180 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
f49c857f PNA |
181 | struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; |
182 | struct nlattr *attr = (void *)nlh + min_len; | |
183 | int attrlen = nlh->nlmsg_len - min_len; | |
c14b78e7 | 184 | __u8 subsys_id = NFNL_SUBSYS_ID(type); |
f49c857f PNA |
185 | |
186 | err = nla_parse(cda, ss->cb[cb_id].attr_count, | |
187 | attr, attrlen, ss->cb[cb_id].policy); | |
4009e188 TB |
188 | if (err < 0) { |
189 | rcu_read_unlock(); | |
f49c857f | 190 | return err; |
4009e188 | 191 | } |
601e68e1 | 192 | |
6b75e3e8 ED |
193 | if (nc->call_rcu) { |
194 | err = nc->call_rcu(net->nfnl, skb, nlh, | |
195 | (const struct nlattr **)cda); | |
196 | rcu_read_unlock(); | |
197 | } else { | |
198 | rcu_read_unlock(); | |
c14b78e7 PNA |
199 | nfnl_lock(subsys_id); |
200 | if (rcu_dereference_protected(table[subsys_id].subsys, | |
9df9e783 | 201 | lockdep_is_held(&table[subsys_id].mutex)) != ss || |
6b75e3e8 ED |
202 | nfnetlink_find_client(type, ss) != nc) |
203 | err = -EAGAIN; | |
59560a38 | 204 | else if (nc->call) |
6b75e3e8 ED |
205 | err = nc->call(net->nfnl, skb, nlh, |
206 | (const struct nlattr **)cda); | |
59560a38 TB |
207 | else |
208 | err = -EINVAL; | |
c14b78e7 | 209 | nfnl_unlock(subsys_id); |
6b75e3e8 | 210 | } |
e6a7d3c0 PNA |
211 | if (err == -EAGAIN) |
212 | goto replay; | |
213 | return err; | |
f9e815b3 | 214 | } |
f9e815b3 HW |
215 | } |
216 | ||
0628b123 PNA |
217 | static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, |
218 | u_int16_t subsys_id) | |
219 | { | |
220 | struct sk_buff *nskb, *oskb = skb; | |
221 | struct net *net = sock_net(skb->sk); | |
222 | const struct nfnetlink_subsystem *ss; | |
223 | const struct nfnl_callback *nc; | |
224 | bool success = true, done = false; | |
225 | int err; | |
226 | ||
227 | if (subsys_id >= NFNL_SUBSYS_COUNT) | |
228 | return netlink_ack(skb, nlh, -EINVAL); | |
229 | replay: | |
230 | nskb = netlink_skb_clone(oskb, GFP_KERNEL); | |
231 | if (!nskb) | |
232 | return netlink_ack(oskb, nlh, -ENOMEM); | |
233 | ||
234 | nskb->sk = oskb->sk; | |
235 | skb = nskb; | |
236 | ||
237 | nfnl_lock(subsys_id); | |
238 | ss = rcu_dereference_protected(table[subsys_id].subsys, | |
239 | lockdep_is_held(&table[subsys_id].mutex)); | |
240 | if (!ss) { | |
241 | #ifdef CONFIG_MODULES | |
242 | nfnl_unlock(subsys_id); | |
243 | request_module("nfnetlink-subsys-%d", subsys_id); | |
244 | nfnl_lock(subsys_id); | |
245 | ss = rcu_dereference_protected(table[subsys_id].subsys, | |
246 | lockdep_is_held(&table[subsys_id].mutex)); | |
247 | if (!ss) | |
248 | #endif | |
249 | { | |
250 | nfnl_unlock(subsys_id); | |
251 | kfree_skb(nskb); | |
252 | return netlink_ack(skb, nlh, -EOPNOTSUPP); | |
253 | } | |
254 | } | |
255 | ||
256 | if (!ss->commit || !ss->abort) { | |
257 | nfnl_unlock(subsys_id); | |
258 | kfree_skb(nskb); | |
259 | return netlink_ack(skb, nlh, -EOPNOTSUPP); | |
260 | } | |
261 | ||
262 | while (skb->len >= nlmsg_total_size(0)) { | |
263 | int msglen, type; | |
264 | ||
265 | nlh = nlmsg_hdr(skb); | |
266 | err = 0; | |
267 | ||
268 | if (nlh->nlmsg_len < NLMSG_HDRLEN) { | |
269 | err = -EINVAL; | |
270 | goto ack; | |
271 | } | |
272 | ||
273 | /* Only requests are handled by the kernel */ | |
274 | if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { | |
275 | err = -EINVAL; | |
276 | goto ack; | |
277 | } | |
278 | ||
279 | type = nlh->nlmsg_type; | |
280 | if (type == NFNL_MSG_BATCH_BEGIN) { | |
281 | /* Malformed: Batch begin twice */ | |
282 | success = false; | |
283 | goto done; | |
284 | } else if (type == NFNL_MSG_BATCH_END) { | |
285 | done = true; | |
286 | goto done; | |
287 | } else if (type < NLMSG_MIN_TYPE) { | |
288 | err = -EINVAL; | |
289 | goto ack; | |
290 | } | |
291 | ||
292 | /* We only accept a batch with messages for the same | |
293 | * subsystem. | |
294 | */ | |
295 | if (NFNL_SUBSYS_ID(type) != subsys_id) { | |
296 | err = -EINVAL; | |
297 | goto ack; | |
298 | } | |
299 | ||
300 | nc = nfnetlink_find_client(type, ss); | |
301 | if (!nc) { | |
302 | err = -EINVAL; | |
303 | goto ack; | |
304 | } | |
305 | ||
306 | { | |
307 | int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); | |
308 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); | |
309 | struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; | |
310 | struct nlattr *attr = (void *)nlh + min_len; | |
311 | int attrlen = nlh->nlmsg_len - min_len; | |
312 | ||
313 | err = nla_parse(cda, ss->cb[cb_id].attr_count, | |
314 | attr, attrlen, ss->cb[cb_id].policy); | |
315 | if (err < 0) | |
316 | goto ack; | |
317 | ||
318 | if (nc->call_batch) { | |
319 | err = nc->call_batch(net->nfnl, skb, nlh, | |
320 | (const struct nlattr **)cda); | |
321 | } | |
322 | ||
323 | /* The lock was released to autoload some module, we | |
324 | * have to abort and start from scratch using the | |
325 | * original skb. | |
326 | */ | |
327 | if (err == -EAGAIN) { | |
328 | ss->abort(skb); | |
329 | nfnl_unlock(subsys_id); | |
330 | kfree_skb(nskb); | |
331 | goto replay; | |
332 | } | |
333 | } | |
334 | ack: | |
335 | if (nlh->nlmsg_flags & NLM_F_ACK || err) { | |
336 | /* We don't stop processing the batch on errors, thus, | |
337 | * userspace gets all the errors that the batch | |
338 | * triggers. | |
339 | */ | |
340 | netlink_ack(skb, nlh, err); | |
341 | if (err) | |
342 | success = false; | |
343 | } | |
344 | ||
345 | msglen = NLMSG_ALIGN(nlh->nlmsg_len); | |
346 | if (msglen > skb->len) | |
347 | msglen = skb->len; | |
348 | skb_pull(skb, msglen); | |
349 | } | |
350 | done: | |
351 | if (success && done) | |
352 | ss->commit(skb); | |
353 | else | |
354 | ss->abort(skb); | |
355 | ||
356 | nfnl_unlock(subsys_id); | |
357 | kfree_skb(nskb); | |
358 | } | |
359 | ||
cd40b7d3 | 360 | static void nfnetlink_rcv(struct sk_buff *skb) |
f9e815b3 | 361 | { |
0628b123 PNA |
362 | struct nlmsghdr *nlh = nlmsg_hdr(skb); |
363 | struct net *net = sock_net(skb->sk); | |
364 | int msglen; | |
365 | ||
0628b123 PNA |
366 | if (nlh->nlmsg_len < NLMSG_HDRLEN || |
367 | skb->len < nlh->nlmsg_len) | |
368 | return; | |
369 | ||
cdbe7c2d JB |
370 | if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) { |
371 | netlink_ack(skb, nlh, -EPERM); | |
372 | return; | |
373 | } | |
374 | ||
0628b123 PNA |
375 | if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) { |
376 | struct nfgenmsg *nfgenmsg; | |
377 | ||
378 | msglen = NLMSG_ALIGN(nlh->nlmsg_len); | |
379 | if (msglen > skb->len) | |
380 | msglen = skb->len; | |
381 | ||
382 | if (nlh->nlmsg_len < NLMSG_HDRLEN || | |
383 | skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) | |
384 | return; | |
385 | ||
386 | nfgenmsg = nlmsg_data(nlh); | |
387 | skb_pull(skb, msglen); | |
388 | nfnetlink_rcv_batch(skb, nlh, nfgenmsg->res_id); | |
389 | } else { | |
390 | netlink_rcv_skb(skb, &nfnetlink_rcv_msg); | |
391 | } | |
f9e815b3 HW |
392 | } |
393 | ||
03292745 PNA |
394 | #ifdef CONFIG_MODULES |
395 | static void nfnetlink_bind(int group) | |
396 | { | |
397 | const struct nfnetlink_subsystem *ss; | |
398 | int type = nfnl_group2type[group]; | |
399 | ||
400 | rcu_read_lock(); | |
401 | ss = nfnetlink_get_subsys(type); | |
402 | if (!ss) { | |
403 | rcu_read_unlock(); | |
404 | request_module("nfnetlink-subsys-%d", type); | |
405 | return; | |
406 | } | |
407 | rcu_read_unlock(); | |
408 | } | |
409 | #endif | |
410 | ||
cd8c20b6 | 411 | static int __net_init nfnetlink_net_init(struct net *net) |
f9e815b3 | 412 | { |
cd8c20b6 | 413 | struct sock *nfnl; |
a31f2d17 PNA |
414 | struct netlink_kernel_cfg cfg = { |
415 | .groups = NFNLGRP_MAX, | |
416 | .input = nfnetlink_rcv, | |
03292745 PNA |
417 | #ifdef CONFIG_MODULES |
418 | .bind = nfnetlink_bind, | |
419 | #endif | |
a31f2d17 | 420 | }; |
cd8c20b6 | 421 | |
9f00d977 | 422 | nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); |
cd8c20b6 AD |
423 | if (!nfnl) |
424 | return -ENOMEM; | |
425 | net->nfnl_stash = nfnl; | |
cf778b00 | 426 | rcu_assign_pointer(net->nfnl, nfnl); |
cd8c20b6 | 427 | return 0; |
f9e815b3 HW |
428 | } |
429 | ||
cd8c20b6 | 430 | static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) |
f9e815b3 | 431 | { |
cd8c20b6 | 432 | struct net *net; |
f9e815b3 | 433 | |
cd8c20b6 | 434 | list_for_each_entry(net, net_exit_list, exit_list) |
a9b3cd7f | 435 | RCU_INIT_POINTER(net->nfnl, NULL); |
cd8c20b6 AD |
436 | synchronize_net(); |
437 | list_for_each_entry(net, net_exit_list, exit_list) | |
438 | netlink_kernel_release(net->nfnl_stash); | |
439 | } | |
f9e815b3 | 440 | |
cd8c20b6 AD |
441 | static struct pernet_operations nfnetlink_net_ops = { |
442 | .init = nfnetlink_net_init, | |
443 | .exit_batch = nfnetlink_net_exit_batch, | |
444 | }; | |
445 | ||
446 | static int __init nfnetlink_init(void) | |
447 | { | |
c14b78e7 PNA |
448 | int i; |
449 | ||
450 | for (i=0; i<NFNL_SUBSYS_COUNT; i++) | |
451 | mutex_init(&table[i].mutex); | |
452 | ||
654d0fbd | 453 | pr_info("Netfilter messages via NETLINK v%s.\n", nfversion); |
cd8c20b6 | 454 | return register_pernet_subsys(&nfnetlink_net_ops); |
f9e815b3 HW |
455 | } |
456 | ||
cd8c20b6 AD |
457 | static void __exit nfnetlink_exit(void) |
458 | { | |
654d0fbd | 459 | pr_info("Removing netfilter NETLINK layer.\n"); |
cd8c20b6 AD |
460 | unregister_pernet_subsys(&nfnetlink_net_ops); |
461 | } | |
f9e815b3 HW |
462 | module_init(nfnetlink_init); |
463 | module_exit(nfnetlink_exit); |