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 <net/netns/generic.h> |
32 | #include <linux/netfilter.h> |
33 | #include <linux/netfilter/nfnetlink.h> |
34 | |
35 | MODULE_LICENSE("GPL" ); |
36 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>" ); |
37 | MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); |
38 | MODULE_DESCRIPTION("Netfilter messages via netlink socket" ); |
39 | |
40 | #define nfnl_dereference_protected(id) \ |
41 | rcu_dereference_protected(table[(id)].subsys, \ |
42 | lockdep_nfnl_is_held((id))) |
43 | |
44 | #define NFNL_MAX_ATTR_COUNT 32 |
45 | |
46 | static unsigned int nfnetlink_pernet_id __read_mostly; |
47 | |
48 | #ifdef CONFIG_NF_CONNTRACK_EVENTS |
49 | static DEFINE_SPINLOCK(nfnl_grp_active_lock); |
50 | #endif |
51 | |
52 | struct nfnl_net { |
53 | struct sock *nfnl; |
54 | }; |
55 | |
56 | static struct { |
57 | struct mutex mutex; |
58 | const struct nfnetlink_subsystem __rcu *subsys; |
59 | } table[NFNL_SUBSYS_COUNT]; |
60 | |
61 | static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT]; |
62 | |
63 | static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = { |
64 | [NFNL_SUBSYS_NONE] = "nfnl_subsys_none" , |
65 | [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink" , |
66 | [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp" , |
67 | [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue" , |
68 | [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog" , |
69 | [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf" , |
70 | [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset" , |
71 | [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct" , |
72 | [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout" , |
73 | [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper" , |
74 | [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables" , |
75 | [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat" , |
76 | [NFNL_SUBSYS_HOOK] = "nfnl_subsys_hook" , |
77 | }; |
78 | |
79 | static const int nfnl_group2type[NFNLGRP_MAX+1] = { |
80 | [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK, |
81 | [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK, |
82 | [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK, |
83 | [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP, |
84 | [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP, |
85 | [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP, |
86 | [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES, |
87 | [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT, |
88 | [NFNLGRP_NFTRACE] = NFNL_SUBSYS_NFTABLES, |
89 | }; |
90 | |
91 | static struct nfnl_net *nfnl_pernet(struct net *net) |
92 | { |
93 | return net_generic(net, id: nfnetlink_pernet_id); |
94 | } |
95 | |
96 | void nfnl_lock(__u8 subsys_id) |
97 | { |
98 | mutex_lock(&table[subsys_id].mutex); |
99 | } |
100 | EXPORT_SYMBOL_GPL(nfnl_lock); |
101 | |
102 | void nfnl_unlock(__u8 subsys_id) |
103 | { |
104 | mutex_unlock(lock: &table[subsys_id].mutex); |
105 | } |
106 | EXPORT_SYMBOL_GPL(nfnl_unlock); |
107 | |
108 | #ifdef CONFIG_PROVE_LOCKING |
109 | bool lockdep_nfnl_is_held(u8 subsys_id) |
110 | { |
111 | return lockdep_is_held(&table[subsys_id].mutex); |
112 | } |
113 | EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held); |
114 | #endif |
115 | |
116 | int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n) |
117 | { |
118 | u8 cb_id; |
119 | |
120 | /* Sanity-check attr_count size to avoid stack buffer overflow. */ |
121 | for (cb_id = 0; cb_id < n->cb_count; cb_id++) |
122 | if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT)) |
123 | return -EINVAL; |
124 | |
125 | nfnl_lock(n->subsys_id); |
126 | if (table[n->subsys_id].subsys) { |
127 | nfnl_unlock(n->subsys_id); |
128 | return -EBUSY; |
129 | } |
130 | rcu_assign_pointer(table[n->subsys_id].subsys, n); |
131 | nfnl_unlock(n->subsys_id); |
132 | |
133 | return 0; |
134 | } |
135 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_register); |
136 | |
137 | int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n) |
138 | { |
139 | nfnl_lock(n->subsys_id); |
140 | table[n->subsys_id].subsys = NULL; |
141 | nfnl_unlock(n->subsys_id); |
142 | synchronize_rcu(); |
143 | return 0; |
144 | } |
145 | EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister); |
146 | |
147 | static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type) |
148 | { |
149 | u8 subsys_id = NFNL_SUBSYS_ID(type); |
150 | |
151 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
152 | return NULL; |
153 | |
154 | return rcu_dereference(table[subsys_id].subsys); |
155 | } |
156 | |
157 | static inline const struct nfnl_callback * |
158 | nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss) |
159 | { |
160 | u8 cb_id = NFNL_MSG_TYPE(type); |
161 | |
162 | if (cb_id >= ss->cb_count) |
163 | return NULL; |
164 | |
165 | return &ss->cb[cb_id]; |
166 | } |
167 | |
168 | int nfnetlink_has_listeners(struct net *net, unsigned int group) |
169 | { |
170 | struct nfnl_net *nfnlnet = nfnl_pernet(net); |
171 | |
172 | return netlink_has_listeners(sk: nfnlnet->nfnl, group); |
173 | } |
174 | EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); |
175 | |
176 | int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid, |
177 | unsigned int group, int echo, gfp_t flags) |
178 | { |
179 | struct nfnl_net *nfnlnet = nfnl_pernet(net); |
180 | |
181 | return nlmsg_notify(sk: nfnlnet->nfnl, skb, portid, group, report: echo, flags); |
182 | } |
183 | EXPORT_SYMBOL_GPL(nfnetlink_send); |
184 | |
185 | int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error) |
186 | { |
187 | struct nfnl_net *nfnlnet = nfnl_pernet(net); |
188 | |
189 | return netlink_set_err(ssk: nfnlnet->nfnl, portid, group, code: error); |
190 | } |
191 | EXPORT_SYMBOL_GPL(nfnetlink_set_err); |
192 | |
193 | int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid) |
194 | { |
195 | struct nfnl_net *nfnlnet = nfnl_pernet(net); |
196 | int err; |
197 | |
198 | err = nlmsg_unicast(sk: nfnlnet->nfnl, skb, portid); |
199 | if (err == -EAGAIN) |
200 | err = -ENOBUFS; |
201 | |
202 | return err; |
203 | } |
204 | EXPORT_SYMBOL_GPL(nfnetlink_unicast); |
205 | |
206 | void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid, |
207 | __u32 group, gfp_t allocation) |
208 | { |
209 | struct nfnl_net *nfnlnet = nfnl_pernet(net); |
210 | |
211 | netlink_broadcast(ssk: nfnlnet->nfnl, skb, portid, group, allocation); |
212 | } |
213 | EXPORT_SYMBOL_GPL(nfnetlink_broadcast); |
214 | |
215 | /* Process one complete nfnetlink message. */ |
216 | static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, |
217 | struct netlink_ext_ack *extack) |
218 | { |
219 | struct net *net = sock_net(sk: skb->sk); |
220 | const struct nfnl_callback *nc; |
221 | const struct nfnetlink_subsystem *ss; |
222 | int type, err; |
223 | |
224 | /* All the messages must at least contain nfgenmsg */ |
225 | if (nlmsg_len(nlh) < sizeof(struct nfgenmsg)) |
226 | return 0; |
227 | |
228 | type = nlh->nlmsg_type; |
229 | replay: |
230 | rcu_read_lock(); |
231 | |
232 | ss = nfnetlink_get_subsys(type); |
233 | if (!ss) { |
234 | #ifdef CONFIG_MODULES |
235 | rcu_read_unlock(); |
236 | request_module("nfnetlink-subsys-%d" , NFNL_SUBSYS_ID(type)); |
237 | rcu_read_lock(); |
238 | ss = nfnetlink_get_subsys(type); |
239 | if (!ss) |
240 | #endif |
241 | { |
242 | rcu_read_unlock(); |
243 | return -EINVAL; |
244 | } |
245 | } |
246 | |
247 | nc = nfnetlink_find_client(type, ss); |
248 | if (!nc) { |
249 | rcu_read_unlock(); |
250 | return -EINVAL; |
251 | } |
252 | |
253 | { |
254 | int min_len = nlmsg_total_size(payload: sizeof(struct nfgenmsg)); |
255 | struct nfnl_net *nfnlnet = nfnl_pernet(net); |
256 | u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
257 | struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1]; |
258 | struct nlattr *attr = (void *)nlh + min_len; |
259 | int attrlen = nlh->nlmsg_len - min_len; |
260 | __u8 subsys_id = NFNL_SUBSYS_ID(type); |
261 | struct nfnl_info info = { |
262 | .net = net, |
263 | .sk = nfnlnet->nfnl, |
264 | .nlh = nlh, |
265 | .nfmsg = nlmsg_data(nlh), |
266 | .extack = extack, |
267 | }; |
268 | |
269 | /* Sanity-check NFNL_MAX_ATTR_COUNT */ |
270 | if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) { |
271 | rcu_read_unlock(); |
272 | return -ENOMEM; |
273 | } |
274 | |
275 | err = nla_parse_deprecated(tb: cda, maxtype: ss->cb[cb_id].attr_count, |
276 | head: attr, len: attrlen, |
277 | policy: ss->cb[cb_id].policy, extack); |
278 | if (err < 0) { |
279 | rcu_read_unlock(); |
280 | return err; |
281 | } |
282 | |
283 | if (!nc->call) { |
284 | rcu_read_unlock(); |
285 | return -EINVAL; |
286 | } |
287 | |
288 | switch (nc->type) { |
289 | case NFNL_CB_RCU: |
290 | err = nc->call(skb, &info, (const struct nlattr **)cda); |
291 | rcu_read_unlock(); |
292 | break; |
293 | case NFNL_CB_MUTEX: |
294 | rcu_read_unlock(); |
295 | nfnl_lock(subsys_id); |
296 | if (nfnl_dereference_protected(subsys_id) != ss || |
297 | nfnetlink_find_client(type, ss) != nc) { |
298 | nfnl_unlock(subsys_id); |
299 | err = -EAGAIN; |
300 | break; |
301 | } |
302 | err = nc->call(skb, &info, (const struct nlattr **)cda); |
303 | nfnl_unlock(subsys_id); |
304 | break; |
305 | default: |
306 | rcu_read_unlock(); |
307 | err = -EINVAL; |
308 | break; |
309 | } |
310 | if (err == -EAGAIN) |
311 | goto replay; |
312 | return err; |
313 | } |
314 | } |
315 | |
316 | struct nfnl_err { |
317 | struct list_head head; |
318 | struct nlmsghdr *nlh; |
319 | int err; |
320 | struct netlink_ext_ack extack; |
321 | }; |
322 | |
323 | static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err, |
324 | const struct netlink_ext_ack *extack) |
325 | { |
326 | struct nfnl_err *nfnl_err; |
327 | |
328 | nfnl_err = kmalloc(size: sizeof(struct nfnl_err), GFP_KERNEL); |
329 | if (nfnl_err == NULL) |
330 | return -ENOMEM; |
331 | |
332 | nfnl_err->nlh = nlh; |
333 | nfnl_err->err = err; |
334 | nfnl_err->extack = *extack; |
335 | list_add_tail(new: &nfnl_err->head, head: list); |
336 | |
337 | return 0; |
338 | } |
339 | |
340 | static void nfnl_err_del(struct nfnl_err *nfnl_err) |
341 | { |
342 | list_del(entry: &nfnl_err->head); |
343 | kfree(objp: nfnl_err); |
344 | } |
345 | |
346 | static void nfnl_err_reset(struct list_head *err_list) |
347 | { |
348 | struct nfnl_err *nfnl_err, *next; |
349 | |
350 | list_for_each_entry_safe(nfnl_err, next, err_list, head) |
351 | nfnl_err_del(nfnl_err); |
352 | } |
353 | |
354 | static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb) |
355 | { |
356 | struct nfnl_err *nfnl_err, *next; |
357 | |
358 | list_for_each_entry_safe(nfnl_err, next, err_list, head) { |
359 | netlink_ack(in_skb: skb, nlh: nfnl_err->nlh, err: nfnl_err->err, |
360 | extack: &nfnl_err->extack); |
361 | nfnl_err_del(nfnl_err); |
362 | } |
363 | } |
364 | |
365 | enum { |
366 | NFNL_BATCH_FAILURE = (1 << 0), |
367 | NFNL_BATCH_DONE = (1 << 1), |
368 | NFNL_BATCH_REPLAY = (1 << 2), |
369 | }; |
370 | |
371 | static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, |
372 | u16 subsys_id, u32 genid) |
373 | { |
374 | struct sk_buff *oskb = skb; |
375 | struct net *net = sock_net(sk: skb->sk); |
376 | const struct nfnetlink_subsystem *ss; |
377 | const struct nfnl_callback *nc; |
378 | struct netlink_ext_ack extack; |
379 | LIST_HEAD(err_list); |
380 | u32 status; |
381 | int err; |
382 | |
383 | if (subsys_id >= NFNL_SUBSYS_COUNT) |
384 | return netlink_ack(in_skb: skb, nlh, err: -EINVAL, NULL); |
385 | replay: |
386 | status = 0; |
387 | replay_abort: |
388 | skb = netlink_skb_clone(skb: oskb, GFP_KERNEL); |
389 | if (!skb) |
390 | return netlink_ack(in_skb: oskb, nlh, err: -ENOMEM, NULL); |
391 | |
392 | nfnl_lock(subsys_id); |
393 | ss = nfnl_dereference_protected(subsys_id); |
394 | if (!ss) { |
395 | #ifdef CONFIG_MODULES |
396 | nfnl_unlock(subsys_id); |
397 | request_module("nfnetlink-subsys-%d" , subsys_id); |
398 | nfnl_lock(subsys_id); |
399 | ss = nfnl_dereference_protected(subsys_id); |
400 | if (!ss) |
401 | #endif |
402 | { |
403 | nfnl_unlock(subsys_id); |
404 | netlink_ack(in_skb: oskb, nlh, err: -EOPNOTSUPP, NULL); |
405 | return kfree_skb(skb); |
406 | } |
407 | } |
408 | |
409 | if (!ss->valid_genid || !ss->commit || !ss->abort) { |
410 | nfnl_unlock(subsys_id); |
411 | netlink_ack(in_skb: oskb, nlh, err: -EOPNOTSUPP, NULL); |
412 | return kfree_skb(skb); |
413 | } |
414 | |
415 | if (!try_module_get(module: ss->owner)) { |
416 | nfnl_unlock(subsys_id); |
417 | netlink_ack(in_skb: oskb, nlh, err: -EOPNOTSUPP, NULL); |
418 | return kfree_skb(skb); |
419 | } |
420 | |
421 | if (!ss->valid_genid(net, genid)) { |
422 | module_put(module: ss->owner); |
423 | nfnl_unlock(subsys_id); |
424 | netlink_ack(in_skb: oskb, nlh, err: -ERESTART, NULL); |
425 | return kfree_skb(skb); |
426 | } |
427 | |
428 | nfnl_unlock(subsys_id); |
429 | |
430 | while (skb->len >= nlmsg_total_size(payload: 0)) { |
431 | int msglen, type; |
432 | |
433 | if (fatal_signal_pending(current)) { |
434 | nfnl_err_reset(err_list: &err_list); |
435 | err = -EINTR; |
436 | status = NFNL_BATCH_FAILURE; |
437 | goto done; |
438 | } |
439 | |
440 | memset(&extack, 0, sizeof(extack)); |
441 | nlh = nlmsg_hdr(skb); |
442 | err = 0; |
443 | |
444 | if (nlh->nlmsg_len < NLMSG_HDRLEN || |
445 | skb->len < nlh->nlmsg_len || |
446 | nlmsg_len(nlh) < sizeof(struct nfgenmsg)) { |
447 | nfnl_err_reset(err_list: &err_list); |
448 | status |= NFNL_BATCH_FAILURE; |
449 | goto done; |
450 | } |
451 | |
452 | /* Only requests are handled by the kernel */ |
453 | if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) { |
454 | err = -EINVAL; |
455 | goto ack; |
456 | } |
457 | |
458 | type = nlh->nlmsg_type; |
459 | if (type == NFNL_MSG_BATCH_BEGIN) { |
460 | /* Malformed: Batch begin twice */ |
461 | nfnl_err_reset(err_list: &err_list); |
462 | status |= NFNL_BATCH_FAILURE; |
463 | goto done; |
464 | } else if (type == NFNL_MSG_BATCH_END) { |
465 | status |= NFNL_BATCH_DONE; |
466 | goto done; |
467 | } else if (type < NLMSG_MIN_TYPE) { |
468 | err = -EINVAL; |
469 | goto ack; |
470 | } |
471 | |
472 | /* We only accept a batch with messages for the same |
473 | * subsystem. |
474 | */ |
475 | if (NFNL_SUBSYS_ID(type) != subsys_id) { |
476 | err = -EINVAL; |
477 | goto ack; |
478 | } |
479 | |
480 | nc = nfnetlink_find_client(type, ss); |
481 | if (!nc) { |
482 | err = -EINVAL; |
483 | goto ack; |
484 | } |
485 | |
486 | if (nc->type != NFNL_CB_BATCH) { |
487 | err = -EINVAL; |
488 | goto ack; |
489 | } |
490 | |
491 | { |
492 | int min_len = nlmsg_total_size(payload: sizeof(struct nfgenmsg)); |
493 | struct nfnl_net *nfnlnet = nfnl_pernet(net); |
494 | struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1]; |
495 | struct nlattr *attr = (void *)nlh + min_len; |
496 | u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type); |
497 | int attrlen = nlh->nlmsg_len - min_len; |
498 | struct nfnl_info info = { |
499 | .net = net, |
500 | .sk = nfnlnet->nfnl, |
501 | .nlh = nlh, |
502 | .nfmsg = nlmsg_data(nlh), |
503 | .extack = &extack, |
504 | }; |
505 | |
506 | /* Sanity-check NFTA_MAX_ATTR */ |
507 | if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) { |
508 | err = -ENOMEM; |
509 | goto ack; |
510 | } |
511 | |
512 | err = nla_parse_deprecated(tb: cda, |
513 | maxtype: ss->cb[cb_id].attr_count, |
514 | head: attr, len: attrlen, |
515 | policy: ss->cb[cb_id].policy, NULL); |
516 | if (err < 0) |
517 | goto ack; |
518 | |
519 | err = nc->call(skb, &info, (const struct nlattr **)cda); |
520 | |
521 | /* The lock was released to autoload some module, we |
522 | * have to abort and start from scratch using the |
523 | * original skb. |
524 | */ |
525 | if (err == -EAGAIN) { |
526 | status |= NFNL_BATCH_REPLAY; |
527 | goto done; |
528 | } |
529 | } |
530 | ack: |
531 | if (nlh->nlmsg_flags & NLM_F_ACK || err) { |
532 | /* Errors are delivered once the full batch has been |
533 | * processed, this avoids that the same error is |
534 | * reported several times when replaying the batch. |
535 | */ |
536 | if (err == -ENOMEM || |
537 | nfnl_err_add(list: &err_list, nlh, err, extack: &extack) < 0) { |
538 | /* We failed to enqueue an error, reset the |
539 | * list of errors and send OOM to userspace |
540 | * pointing to the batch header. |
541 | */ |
542 | nfnl_err_reset(err_list: &err_list); |
543 | netlink_ack(in_skb: oskb, nlh: nlmsg_hdr(skb: oskb), err: -ENOMEM, |
544 | NULL); |
545 | status |= NFNL_BATCH_FAILURE; |
546 | goto done; |
547 | } |
548 | /* We don't stop processing the batch on errors, thus, |
549 | * userspace gets all the errors that the batch |
550 | * triggers. |
551 | */ |
552 | if (err) |
553 | status |= NFNL_BATCH_FAILURE; |
554 | } |
555 | |
556 | msglen = NLMSG_ALIGN(nlh->nlmsg_len); |
557 | if (msglen > skb->len) |
558 | msglen = skb->len; |
559 | skb_pull(skb, len: msglen); |
560 | } |
561 | done: |
562 | if (status & NFNL_BATCH_REPLAY) { |
563 | ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD); |
564 | nfnl_err_reset(err_list: &err_list); |
565 | kfree_skb(skb); |
566 | module_put(module: ss->owner); |
567 | goto replay; |
568 | } else if (status == NFNL_BATCH_DONE) { |
569 | err = ss->commit(net, oskb); |
570 | if (err == -EAGAIN) { |
571 | status |= NFNL_BATCH_REPLAY; |
572 | goto done; |
573 | } else if (err) { |
574 | ss->abort(net, oskb, NFNL_ABORT_NONE); |
575 | netlink_ack(in_skb: oskb, nlh: nlmsg_hdr(skb: oskb), err, NULL); |
576 | } |
577 | } else { |
578 | enum nfnl_abort_action abort_action; |
579 | |
580 | if (status & NFNL_BATCH_FAILURE) |
581 | abort_action = NFNL_ABORT_NONE; |
582 | else |
583 | abort_action = NFNL_ABORT_VALIDATE; |
584 | |
585 | err = ss->abort(net, oskb, abort_action); |
586 | if (err == -EAGAIN) { |
587 | nfnl_err_reset(err_list: &err_list); |
588 | kfree_skb(skb); |
589 | module_put(module: ss->owner); |
590 | status |= NFNL_BATCH_FAILURE; |
591 | goto replay_abort; |
592 | } |
593 | } |
594 | |
595 | nfnl_err_deliver(err_list: &err_list, skb: oskb); |
596 | kfree_skb(skb); |
597 | module_put(module: ss->owner); |
598 | } |
599 | |
600 | static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = { |
601 | [NFNL_BATCH_GENID] = { .type = NLA_U32 }, |
602 | }; |
603 | |
604 | static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh) |
605 | { |
606 | int min_len = nlmsg_total_size(payload: sizeof(struct nfgenmsg)); |
607 | struct nlattr *attr = (void *)nlh + min_len; |
608 | struct nlattr *cda[NFNL_BATCH_MAX + 1]; |
609 | int attrlen = nlh->nlmsg_len - min_len; |
610 | struct nfgenmsg *nfgenmsg; |
611 | int msglen, err; |
612 | u32 gen_id = 0; |
613 | u16 res_id; |
614 | |
615 | msglen = NLMSG_ALIGN(nlh->nlmsg_len); |
616 | if (msglen > skb->len) |
617 | msglen = skb->len; |
618 | |
619 | if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) |
620 | return; |
621 | |
622 | err = nla_parse_deprecated(tb: cda, NFNL_BATCH_MAX, head: attr, len: attrlen, |
623 | policy: nfnl_batch_policy, NULL); |
624 | if (err < 0) { |
625 | netlink_ack(in_skb: skb, nlh, err, NULL); |
626 | return; |
627 | } |
628 | if (cda[NFNL_BATCH_GENID]) |
629 | gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID])); |
630 | |
631 | nfgenmsg = nlmsg_data(nlh); |
632 | skb_pull(skb, len: msglen); |
633 | /* Work around old nft using host byte order */ |
634 | if (nfgenmsg->res_id == (__force __be16)NFNL_SUBSYS_NFTABLES) |
635 | res_id = NFNL_SUBSYS_NFTABLES; |
636 | else |
637 | res_id = ntohs(nfgenmsg->res_id); |
638 | |
639 | nfnetlink_rcv_batch(skb, nlh, subsys_id: res_id, genid: gen_id); |
640 | } |
641 | |
642 | static void nfnetlink_rcv(struct sk_buff *skb) |
643 | { |
644 | struct nlmsghdr *nlh = nlmsg_hdr(skb); |
645 | |
646 | if (skb->len < NLMSG_HDRLEN || |
647 | nlh->nlmsg_len < NLMSG_HDRLEN || |
648 | skb->len < nlh->nlmsg_len) |
649 | return; |
650 | |
651 | if (!netlink_net_capable(skb, CAP_NET_ADMIN)) { |
652 | netlink_ack(in_skb: skb, nlh, err: -EPERM, NULL); |
653 | return; |
654 | } |
655 | |
656 | if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) |
657 | nfnetlink_rcv_skb_batch(skb, nlh); |
658 | else |
659 | netlink_rcv_skb(skb, cb: nfnetlink_rcv_msg); |
660 | } |
661 | |
662 | static void nfnetlink_bind_event(struct net *net, unsigned int group) |
663 | { |
664 | #ifdef CONFIG_NF_CONNTRACK_EVENTS |
665 | int type, group_bit; |
666 | u8 v; |
667 | |
668 | /* All NFNLGRP_CONNTRACK_* group bits fit into u8. |
669 | * The other groups are not relevant and can be ignored. |
670 | */ |
671 | if (group >= 8) |
672 | return; |
673 | |
674 | type = nfnl_group2type[group]; |
675 | |
676 | switch (type) { |
677 | case NFNL_SUBSYS_CTNETLINK: |
678 | break; |
679 | case NFNL_SUBSYS_CTNETLINK_EXP: |
680 | break; |
681 | default: |
682 | return; |
683 | } |
684 | |
685 | group_bit = (1 << group); |
686 | |
687 | spin_lock(lock: &nfnl_grp_active_lock); |
688 | v = READ_ONCE(nf_ctnetlink_has_listener); |
689 | if ((v & group_bit) == 0) { |
690 | v |= group_bit; |
691 | |
692 | /* read concurrently without nfnl_grp_active_lock held. */ |
693 | WRITE_ONCE(nf_ctnetlink_has_listener, v); |
694 | } |
695 | |
696 | spin_unlock(lock: &nfnl_grp_active_lock); |
697 | #endif |
698 | } |
699 | |
700 | static int nfnetlink_bind(struct net *net, int group) |
701 | { |
702 | const struct nfnetlink_subsystem *ss; |
703 | int type; |
704 | |
705 | if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) |
706 | return 0; |
707 | |
708 | type = nfnl_group2type[group]; |
709 | |
710 | rcu_read_lock(); |
711 | ss = nfnetlink_get_subsys(type: type << 8); |
712 | rcu_read_unlock(); |
713 | if (!ss) |
714 | request_module_nowait("nfnetlink-subsys-%d" , type); |
715 | |
716 | nfnetlink_bind_event(net, group); |
717 | return 0; |
718 | } |
719 | |
720 | static void nfnetlink_unbind(struct net *net, int group) |
721 | { |
722 | #ifdef CONFIG_NF_CONNTRACK_EVENTS |
723 | int type, group_bit; |
724 | |
725 | if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX) |
726 | return; |
727 | |
728 | type = nfnl_group2type[group]; |
729 | |
730 | switch (type) { |
731 | case NFNL_SUBSYS_CTNETLINK: |
732 | break; |
733 | case NFNL_SUBSYS_CTNETLINK_EXP: |
734 | break; |
735 | default: |
736 | return; |
737 | } |
738 | |
739 | /* ctnetlink_has_listener is u8 */ |
740 | if (group >= 8) |
741 | return; |
742 | |
743 | group_bit = (1 << group); |
744 | |
745 | spin_lock(lock: &nfnl_grp_active_lock); |
746 | if (!nfnetlink_has_listeners(net, group)) { |
747 | u8 v = READ_ONCE(nf_ctnetlink_has_listener); |
748 | |
749 | v &= ~group_bit; |
750 | |
751 | /* read concurrently without nfnl_grp_active_lock held. */ |
752 | WRITE_ONCE(nf_ctnetlink_has_listener, v); |
753 | } |
754 | spin_unlock(lock: &nfnl_grp_active_lock); |
755 | #endif |
756 | } |
757 | |
758 | static int __net_init nfnetlink_net_init(struct net *net) |
759 | { |
760 | struct nfnl_net *nfnlnet = nfnl_pernet(net); |
761 | struct netlink_kernel_cfg cfg = { |
762 | .groups = NFNLGRP_MAX, |
763 | .input = nfnetlink_rcv, |
764 | .bind = nfnetlink_bind, |
765 | .unbind = nfnetlink_unbind, |
766 | }; |
767 | |
768 | nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, cfg: &cfg); |
769 | if (!nfnlnet->nfnl) |
770 | return -ENOMEM; |
771 | return 0; |
772 | } |
773 | |
774 | static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list) |
775 | { |
776 | struct nfnl_net *nfnlnet; |
777 | struct net *net; |
778 | |
779 | list_for_each_entry(net, net_exit_list, exit_list) { |
780 | nfnlnet = nfnl_pernet(net); |
781 | |
782 | netlink_kernel_release(sk: nfnlnet->nfnl); |
783 | } |
784 | } |
785 | |
786 | static struct pernet_operations nfnetlink_net_ops = { |
787 | .init = nfnetlink_net_init, |
788 | .exit_batch = nfnetlink_net_exit_batch, |
789 | .id = &nfnetlink_pernet_id, |
790 | .size = sizeof(struct nfnl_net), |
791 | }; |
792 | |
793 | static int __init nfnetlink_init(void) |
794 | { |
795 | int i; |
796 | |
797 | for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++) |
798 | BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE); |
799 | |
800 | for (i=0; i<NFNL_SUBSYS_COUNT; i++) |
801 | __mutex_init(lock: &table[i].mutex, name: nfnl_lockdep_names[i], key: &nfnl_lockdep_keys[i]); |
802 | |
803 | return register_pernet_subsys(&nfnetlink_net_ops); |
804 | } |
805 | |
806 | static void __exit nfnetlink_exit(void) |
807 | { |
808 | unregister_pernet_subsys(&nfnetlink_net_ops); |
809 | } |
810 | module_init(nfnetlink_init); |
811 | module_exit(nfnetlink_exit); |
812 | |