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 | |
0eb5db7a PM |
64 | #ifdef CONFIG_PROVE_LOCKING |
65 | int lockdep_nfnl_is_held(u8 subsys_id) | |
66 | { | |
67 | return lockdep_is_held(&table[subsys_id].mutex); | |
68 | } | |
69 | EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held); | |
70 | #endif | |
71 | ||
7c8d4cb4 | 72 | int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
f9e815b3 | 73 | { |
c14b78e7 PNA |
74 | nfnl_lock(n->subsys_id); |
75 | if (table[n->subsys_id].subsys) { | |
76 | nfnl_unlock(n->subsys_id); | |
0ab43f84 HW |
77 | return -EBUSY; |
78 | } | |
c14b78e7 PNA |
79 | rcu_assign_pointer(table[n->subsys_id].subsys, n); |
80 | nfnl_unlock(n->subsys_id); | |
f9e815b3 HW |
81 | |
82 | return 0; | |
83 | } | |
f4bc177f | 84 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
f9e815b3 | 85 | |
7c8d4cb4 | 86 | int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
f9e815b3 | 87 | { |
c14b78e7 PNA |
88 | nfnl_lock(n->subsys_id); |
89 | table[n->subsys_id].subsys = NULL; | |
90 | nfnl_unlock(n->subsys_id); | |
6b75e3e8 | 91 | synchronize_rcu(); |
f9e815b3 HW |
92 | return 0; |
93 | } | |
f4bc177f | 94 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
f9e815b3 | 95 | |
7c8d4cb4 | 96 | static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type) |
f9e815b3 HW |
97 | { |
98 | u_int8_t subsys_id = NFNL_SUBSYS_ID(type); | |
99 | ||
ac0f1d98 | 100 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
f9e815b3 HW |
101 | return NULL; |
102 | ||
c14b78e7 | 103 | return rcu_dereference(table[subsys_id].subsys); |
f9e815b3 HW |
104 | } |
105 | ||
7c8d4cb4 PM |
106 | static inline const struct nfnl_callback * |
107 | nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss) | |
f9e815b3 HW |
108 | { |
109 | u_int8_t cb_id = NFNL_MSG_TYPE(type); | |
601e68e1 | 110 | |
67ca3966 | 111 | if (cb_id >= ss->cb_count) |
f9e815b3 | 112 | return NULL; |
f9e815b3 HW |
113 | |
114 | return &ss->cb[cb_id]; | |
115 | } | |
116 | ||
cd8c20b6 | 117 | int nfnetlink_has_listeners(struct net *net, unsigned int group) |
a2427692 | 118 | { |
cd8c20b6 | 119 | return netlink_has_listeners(net->nfnl, group); |
a2427692 PM |
120 | } |
121 | EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); | |
122 | ||
3ab1f683 PM |
123 | struct sk_buff *nfnetlink_alloc_skb(struct net *net, unsigned int size, |
124 | u32 dst_portid, gfp_t gfp_mask) | |
125 | { | |
126 | return netlink_alloc_skb(net->nfnl, size, dst_portid, gfp_mask); | |
127 | } | |
128 | EXPORT_SYMBOL_GPL(nfnetlink_alloc_skb); | |
129 | ||
ec464e5d | 130 | int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid, |
95c96174 | 131 | unsigned int group, int echo, gfp_t flags) |
f9e815b3 | 132 | { |
ec464e5d | 133 | return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags); |
f9e815b3 | 134 | } |
f4bc177f | 135 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
f9e815b3 | 136 | |
ec464e5d | 137 | int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error) |
dd5b6ce6 | 138 | { |
ec464e5d | 139 | return netlink_set_err(net->nfnl, portid, group, error); |
dd5b6ce6 PNA |
140 | } |
141 | EXPORT_SYMBOL_GPL(nfnetlink_set_err); | |
142 | ||
ec464e5d PM |
143 | int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid, |
144 | int flags) | |
f9e815b3 | 145 | { |
ec464e5d | 146 | return netlink_unicast(net->nfnl, skb, portid, flags); |
f9e815b3 | 147 | } |
f4bc177f | 148 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
f9e815b3 HW |
149 | |
150 | /* Process one complete nfnetlink message. */ | |
1d00a4eb | 151 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) |
f9e815b3 | 152 | { |
cd8c20b6 | 153 | struct net *net = sock_net(skb->sk); |
7c8d4cb4 PM |
154 | const struct nfnl_callback *nc; |
155 | const struct nfnetlink_subsystem *ss; | |
1d00a4eb | 156 | int type, err; |
f9e815b3 | 157 | |
f9e815b3 | 158 | /* All the messages must at least contain nfgenmsg */ |
573ce260 | 159 | if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) |
f9e815b3 | 160 | return 0; |
f9e815b3 HW |
161 | |
162 | type = nlh->nlmsg_type; | |
e6a7d3c0 | 163 | replay: |
6b75e3e8 | 164 | rcu_read_lock(); |
f9e815b3 | 165 | ss = nfnetlink_get_subsys(type); |
0ab43f84 | 166 | if (!ss) { |
95a5afca | 167 | #ifdef CONFIG_MODULES |
6b75e3e8 | 168 | rcu_read_unlock(); |
37d2e7a2 | 169 | request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); |
6b75e3e8 | 170 | rcu_read_lock(); |
37d2e7a2 | 171 | ss = nfnetlink_get_subsys(type); |
0ab43f84 HW |
172 | if (!ss) |
173 | #endif | |
6b75e3e8 ED |
174 | { |
175 | rcu_read_unlock(); | |
1d00a4eb | 176 | return -EINVAL; |
6b75e3e8 | 177 | } |
0ab43f84 | 178 | } |
f9e815b3 HW |
179 | |
180 | nc = nfnetlink_find_client(type, ss); | |
6b75e3e8 ED |
181 | if (!nc) { |
182 | rcu_read_unlock(); | |
1d00a4eb | 183 | return -EINVAL; |
6b75e3e8 | 184 | } |
f9e815b3 | 185 | |
f9e815b3 | 186 | { |
573ce260 | 187 | int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); |
e3730578 | 188 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
f49c857f PNA |
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; | |
c14b78e7 | 192 | __u8 subsys_id = NFNL_SUBSYS_ID(type); |
f49c857f PNA |
193 | |
194 | err = nla_parse(cda, ss->cb[cb_id].attr_count, | |
195 | attr, attrlen, ss->cb[cb_id].policy); | |
4009e188 TB |
196 | if (err < 0) { |
197 | rcu_read_unlock(); | |
f49c857f | 198 | return err; |
4009e188 | 199 | } |
601e68e1 | 200 | |
6b75e3e8 ED |
201 | if (nc->call_rcu) { |
202 | err = nc->call_rcu(net->nfnl, skb, nlh, | |
203 | (const struct nlattr **)cda); | |
204 | rcu_read_unlock(); | |
205 | } else { | |
206 | rcu_read_unlock(); | |
c14b78e7 PNA |
207 | nfnl_lock(subsys_id); |
208 | if (rcu_dereference_protected(table[subsys_id].subsys, | |
9df9e783 | 209 | lockdep_is_held(&table[subsys_id].mutex)) != ss || |
6b75e3e8 ED |
210 | nfnetlink_find_client(type, ss) != nc) |
211 | err = -EAGAIN; | |
59560a38 | 212 | else if (nc->call) |
6b75e3e8 ED |
213 | err = nc->call(net->nfnl, skb, nlh, |
214 | (const struct nlattr **)cda); | |
59560a38 TB |
215 | else |
216 | err = -EINVAL; | |
c14b78e7 | 217 | nfnl_unlock(subsys_id); |
6b75e3e8 | 218 | } |
e6a7d3c0 PNA |
219 | if (err == -EAGAIN) |
220 | goto replay; | |
221 | return err; | |
f9e815b3 | 222 | } |
f9e815b3 HW |
223 | } |
224 | ||
0628b123 PNA |
225 | static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, |
226 | u_int16_t subsys_id) | |
227 | { | |
228 | struct sk_buff *nskb, *oskb = skb; | |
229 | struct net *net = sock_net(skb->sk); | |
230 | const struct nfnetlink_subsystem *ss; | |
231 | const struct nfnl_callback *nc; | |
232 | bool success = true, done = false; | |
233 | int err; | |
234 | ||
235 | if (subsys_id >= NFNL_SUBSYS_COUNT) | |
236 | return netlink_ack(skb, nlh, -EINVAL); | |
237 | replay: | |
238 | nskb = netlink_skb_clone(oskb, GFP_KERNEL); | |
239 | if (!nskb) | |
240 | return netlink_ack(oskb, nlh, -ENOMEM); | |
241 | ||
242 | nskb->sk = oskb->sk; | |
243 | skb = nskb; | |
244 | ||
245 | nfnl_lock(subsys_id); | |
246 | ss = rcu_dereference_protected(table[subsys_id].subsys, | |
247 | lockdep_is_held(&table[subsys_id].mutex)); | |
248 | if (!ss) { | |
249 | #ifdef CONFIG_MODULES | |
250 | nfnl_unlock(subsys_id); | |
251 | request_module("nfnetlink-subsys-%d", subsys_id); | |
252 | nfnl_lock(subsys_id); | |
253 | ss = rcu_dereference_protected(table[subsys_id].subsys, | |
254 | lockdep_is_held(&table[subsys_id].mutex)); | |
255 | if (!ss) | |
256 | #endif | |
257 | { | |
258 | nfnl_unlock(subsys_id); | |
259 | kfree_skb(nskb); | |
260 | return netlink_ack(skb, nlh, -EOPNOTSUPP); | |
261 | } | |
262 | } | |
263 | ||
264 | if (!ss->commit || !ss->abort) { | |
265 | nfnl_unlock(subsys_id); | |
266 | kfree_skb(nskb); | |
267 | return netlink_ack(skb, nlh, -EOPNOTSUPP); | |
268 | } | |
269 | ||
270 | while (skb->len >= nlmsg_total_size(0)) { | |
271 | int msglen, type; | |
272 | ||
273 | nlh = nlmsg_hdr(skb); | |
274 | err = 0; | |
275 | ||
276 | if (nlh->nlmsg_len < NLMSG_HDRLEN) { | |
277 | err = -EINVAL; | |
278 | goto ack; | |
279 | } | |
280 | ||
281 | /* Only requests are handled by the kernel */ | |
282 | if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { | |
283 | err = -EINVAL; | |
284 | goto ack; | |
285 | } | |
286 | ||
287 | type = nlh->nlmsg_type; | |
288 | if (type == NFNL_MSG_BATCH_BEGIN) { | |
289 | /* Malformed: Batch begin twice */ | |
290 | success = false; | |
291 | goto done; | |
292 | } else if (type == NFNL_MSG_BATCH_END) { | |
293 | done = true; | |
294 | goto done; | |
295 | } else if (type < NLMSG_MIN_TYPE) { | |
296 | err = -EINVAL; | |
297 | goto ack; | |
298 | } | |
299 | ||
300 | /* We only accept a batch with messages for the same | |
301 | * subsystem. | |
302 | */ | |
303 | if (NFNL_SUBSYS_ID(type) != subsys_id) { | |
304 | err = -EINVAL; | |
305 | goto ack; | |
306 | } | |
307 | ||
308 | nc = nfnetlink_find_client(type, ss); | |
309 | if (!nc) { | |
310 | err = -EINVAL; | |
311 | goto ack; | |
312 | } | |
313 | ||
314 | { | |
315 | int min_len = nlmsg_total_size(sizeof(struct nfgenmsg)); | |
316 | u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); | |
317 | struct nlattr *cda[ss->cb[cb_id].attr_count + 1]; | |
318 | struct nlattr *attr = (void *)nlh + min_len; | |
319 | int attrlen = nlh->nlmsg_len - min_len; | |
320 | ||
321 | err = nla_parse(cda, ss->cb[cb_id].attr_count, | |
322 | attr, attrlen, ss->cb[cb_id].policy); | |
323 | if (err < 0) | |
324 | goto ack; | |
325 | ||
326 | if (nc->call_batch) { | |
327 | err = nc->call_batch(net->nfnl, skb, nlh, | |
328 | (const struct nlattr **)cda); | |
329 | } | |
330 | ||
331 | /* The lock was released to autoload some module, we | |
332 | * have to abort and start from scratch using the | |
333 | * original skb. | |
334 | */ | |
335 | if (err == -EAGAIN) { | |
336 | ss->abort(skb); | |
337 | nfnl_unlock(subsys_id); | |
338 | kfree_skb(nskb); | |
339 | goto replay; | |
340 | } | |
341 | } | |
342 | ack: | |
343 | if (nlh->nlmsg_flags & NLM_F_ACK || err) { | |
344 | /* We don't stop processing the batch on errors, thus, | |
345 | * userspace gets all the errors that the batch | |
346 | * triggers. | |
347 | */ | |
348 | netlink_ack(skb, nlh, err); | |
349 | if (err) | |
350 | success = false; | |
351 | } | |
352 | ||
353 | msglen = NLMSG_ALIGN(nlh->nlmsg_len); | |
354 | if (msglen > skb->len) | |
355 | msglen = skb->len; | |
356 | skb_pull(skb, msglen); | |
357 | } | |
358 | done: | |
359 | if (success && done) | |
360 | ss->commit(skb); | |
361 | else | |
362 | ss->abort(skb); | |
363 | ||
364 | nfnl_unlock(subsys_id); | |
365 | kfree_skb(nskb); | |
366 | } | |
367 | ||
cd40b7d3 | 368 | static void nfnetlink_rcv(struct sk_buff *skb) |
f9e815b3 | 369 | { |
0628b123 PNA |
370 | struct nlmsghdr *nlh = nlmsg_hdr(skb); |
371 | struct net *net = sock_net(skb->sk); | |
372 | int msglen; | |
373 | ||
0628b123 PNA |
374 | if (nlh->nlmsg_len < NLMSG_HDRLEN || |
375 | skb->len < nlh->nlmsg_len) | |
376 | return; | |
377 | ||
cdbe7c2d JB |
378 | if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) { |
379 | netlink_ack(skb, nlh, -EPERM); | |
380 | return; | |
381 | } | |
382 | ||
0628b123 PNA |
383 | if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) { |
384 | struct nfgenmsg *nfgenmsg; | |
385 | ||
386 | msglen = NLMSG_ALIGN(nlh->nlmsg_len); | |
387 | if (msglen > skb->len) | |
388 | msglen = skb->len; | |
389 | ||
390 | if (nlh->nlmsg_len < NLMSG_HDRLEN || | |
391 | skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) | |
392 | return; | |
393 | ||
394 | nfgenmsg = nlmsg_data(nlh); | |
395 | skb_pull(skb, msglen); | |
396 | nfnetlink_rcv_batch(skb, nlh, nfgenmsg->res_id); | |
397 | } else { | |
398 | netlink_rcv_skb(skb, &nfnetlink_rcv_msg); | |
399 | } | |
f9e815b3 HW |
400 | } |
401 | ||
03292745 PNA |
402 | #ifdef CONFIG_MODULES |
403 | static void nfnetlink_bind(int group) | |
404 | { | |
405 | const struct nfnetlink_subsystem *ss; | |
406 | int type = nfnl_group2type[group]; | |
407 | ||
408 | rcu_read_lock(); | |
409 | ss = nfnetlink_get_subsys(type); | |
410 | if (!ss) { | |
411 | rcu_read_unlock(); | |
412 | request_module("nfnetlink-subsys-%d", type); | |
413 | return; | |
414 | } | |
415 | rcu_read_unlock(); | |
416 | } | |
417 | #endif | |
418 | ||
cd8c20b6 | 419 | static int __net_init nfnetlink_net_init(struct net *net) |
f9e815b3 | 420 | { |
cd8c20b6 | 421 | struct sock *nfnl; |
a31f2d17 PNA |
422 | struct netlink_kernel_cfg cfg = { |
423 | .groups = NFNLGRP_MAX, | |
424 | .input = nfnetlink_rcv, | |
03292745 PNA |
425 | #ifdef CONFIG_MODULES |
426 | .bind = nfnetlink_bind, | |
427 | #endif | |
a31f2d17 | 428 | }; |
cd8c20b6 | 429 | |
9f00d977 | 430 | nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg); |
cd8c20b6 AD |
431 | if (!nfnl) |
432 | return -ENOMEM; | |
433 | net->nfnl_stash = nfnl; | |
cf778b00 | 434 | rcu_assign_pointer(net->nfnl, nfnl); |
cd8c20b6 | 435 | return 0; |
f9e815b3 HW |
436 | } |
437 | ||
cd8c20b6 | 438 | static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) |
f9e815b3 | 439 | { |
cd8c20b6 | 440 | struct net *net; |
f9e815b3 | 441 | |
cd8c20b6 | 442 | list_for_each_entry(net, net_exit_list, exit_list) |
a9b3cd7f | 443 | RCU_INIT_POINTER(net->nfnl, NULL); |
cd8c20b6 AD |
444 | synchronize_net(); |
445 | list_for_each_entry(net, net_exit_list, exit_list) | |
446 | netlink_kernel_release(net->nfnl_stash); | |
447 | } | |
f9e815b3 | 448 | |
cd8c20b6 AD |
449 | static struct pernet_operations nfnetlink_net_ops = { |
450 | .init = nfnetlink_net_init, | |
451 | .exit_batch = nfnetlink_net_exit_batch, | |
452 | }; | |
453 | ||
454 | static int __init nfnetlink_init(void) | |
455 | { | |
c14b78e7 PNA |
456 | int i; |
457 | ||
458 | for (i=0; i<NFNL_SUBSYS_COUNT; i++) | |
459 | mutex_init(&table[i].mutex); | |
460 | ||
654d0fbd | 461 | pr_info("Netfilter messages via NETLINK v%s.\n", nfversion); |
cd8c20b6 | 462 | return register_pernet_subsys(&nfnetlink_net_ops); |
f9e815b3 HW |
463 | } |
464 | ||
cd8c20b6 AD |
465 | static void __exit nfnetlink_exit(void) |
466 | { | |
654d0fbd | 467 | pr_info("Removing netfilter NETLINK layer.\n"); |
cd8c20b6 AD |
468 | unregister_pernet_subsys(&nfnetlink_net_ops); |
469 | } | |
f9e815b3 HW |
470 | module_init(nfnetlink_init); |
471 | module_exit(nfnetlink_exit); |