Commit | Line | Data |
---|---|---|
601e68e1 | 1 | /* netfilter.c: look after the filters for various protocols. |
f6ebe77f HW |
2 | * Heavily influenced by the old firewall.c by David Bonn and Alan Cox. |
3 | * | |
4 | * Thanks to Rob `CmdrTaco' Malda for not influencing this code in any | |
5 | * way. | |
6 | * | |
7 | * Rusty Russell (C)2000 -- This code is GPL. | |
f229f6ce | 8 | * Patrick McHardy (c) 2006-2012 |
f6ebe77f | 9 | */ |
f6ebe77f HW |
10 | #include <linux/kernel.h> |
11 | #include <linux/netfilter.h> | |
12 | #include <net/protocol.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/skbuff.h> | |
15 | #include <linux/wait.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/if.h> | |
19 | #include <linux/netdevice.h> | |
56768644 | 20 | #include <linux/netfilter_ipv6.h> |
f6ebe77f HW |
21 | #include <linux/inetdevice.h> |
22 | #include <linux/proc_fs.h> | |
d486dd1f | 23 | #include <linux/mutex.h> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
457c4cbc | 25 | #include <net/net_namespace.h> |
f6ebe77f HW |
26 | #include <net/sock.h> |
27 | ||
28 | #include "nf_internals.h" | |
29 | ||
d486dd1f | 30 | static DEFINE_MUTEX(afinfo_mutex); |
bce8032e | 31 | |
0906a372 | 32 | const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO] __read_mostly; |
bce8032e | 33 | EXPORT_SYMBOL(nf_afinfo); |
2a7851bf FW |
34 | const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly; |
35 | EXPORT_SYMBOL_GPL(nf_ipv6_ops); | |
bce8032e | 36 | |
e7c8899f FW |
37 | DEFINE_PER_CPU(bool, nf_skb_duplicated); |
38 | EXPORT_SYMBOL_GPL(nf_skb_duplicated); | |
39 | ||
1e796fda | 40 | int nf_register_afinfo(const struct nf_afinfo *afinfo) |
bce8032e | 41 | { |
7926dbfa | 42 | mutex_lock(&afinfo_mutex); |
a9b3cd7f | 43 | RCU_INIT_POINTER(nf_afinfo[afinfo->family], afinfo); |
d486dd1f | 44 | mutex_unlock(&afinfo_mutex); |
bce8032e PM |
45 | return 0; |
46 | } | |
47 | EXPORT_SYMBOL_GPL(nf_register_afinfo); | |
48 | ||
1e796fda | 49 | void nf_unregister_afinfo(const struct nf_afinfo *afinfo) |
bce8032e | 50 | { |
d486dd1f | 51 | mutex_lock(&afinfo_mutex); |
a9b3cd7f | 52 | RCU_INIT_POINTER(nf_afinfo[afinfo->family], NULL); |
d486dd1f | 53 | mutex_unlock(&afinfo_mutex); |
bce8032e PM |
54 | synchronize_rcu(); |
55 | } | |
56 | EXPORT_SYMBOL_GPL(nf_unregister_afinfo); | |
57 | ||
d1c85c2e | 58 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 59 | struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; |
a2d7ec58 ED |
60 | EXPORT_SYMBOL(nf_hooks_needed); |
61 | #endif | |
62 | ||
fd706d69 | 63 | static DEFINE_MUTEX(nf_hook_mutex); |
f6ebe77f | 64 | |
085db2c0 EB |
65 | static struct list_head *find_nf_hook_list(struct net *net, |
66 | const struct nf_hook_ops *reg) | |
f6ebe77f | 67 | { |
0edcf282 | 68 | struct list_head *nf_hook_list = NULL; |
f6ebe77f | 69 | |
0edcf282 | 70 | if (reg->pf != NFPROTO_NETDEV) |
085db2c0 | 71 | nf_hook_list = &net->nf.hooks[reg->pf][reg->hooknum]; |
0edcf282 | 72 | else if (reg->hooknum == NF_NETDEV_INGRESS) { |
e687ad60 | 73 | #ifdef CONFIG_NETFILTER_INGRESS |
085db2c0 | 74 | if (reg->dev && dev_net(reg->dev) == net) |
e687ad60 | 75 | nf_hook_list = ®->dev->nf_hooks_ingress; |
e687ad60 | 76 | #endif |
e687ad60 | 77 | } |
0edcf282 EB |
78 | return nf_hook_list; |
79 | } | |
e687ad60 | 80 | |
7181ebaf PNA |
81 | struct nf_hook_entry { |
82 | const struct nf_hook_ops *orig_ops; | |
83 | struct nf_hook_ops ops; | |
84 | }; | |
85 | ||
085db2c0 | 86 | int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) |
0edcf282 EB |
87 | { |
88 | struct list_head *nf_hook_list; | |
7181ebaf PNA |
89 | struct nf_hook_entry *entry; |
90 | struct nf_hook_ops *elem; | |
085db2c0 | 91 | |
7181ebaf PNA |
92 | entry = kmalloc(sizeof(*entry), GFP_KERNEL); |
93 | if (!entry) | |
085db2c0 | 94 | return -ENOMEM; |
0edcf282 | 95 | |
7181ebaf PNA |
96 | entry->orig_ops = reg; |
97 | entry->ops = *reg; | |
085db2c0 EB |
98 | |
99 | nf_hook_list = find_nf_hook_list(net, reg); | |
e317fa50 | 100 | if (!nf_hook_list) { |
7181ebaf | 101 | kfree(entry); |
0edcf282 | 102 | return -ENOENT; |
e317fa50 | 103 | } |
0edcf282 EB |
104 | |
105 | mutex_lock(&nf_hook_mutex); | |
e687ad60 | 106 | list_for_each_entry(elem, nf_hook_list, list) { |
4c610979 | 107 | if (reg->priority < elem->priority) |
f6ebe77f HW |
108 | break; |
109 | } | |
7181ebaf | 110 | list_add_rcu(&entry->ops.list, elem->list.prev); |
fd706d69 | 111 | mutex_unlock(&nf_hook_mutex); |
4c091156 EB |
112 | #ifdef CONFIG_NETFILTER_INGRESS |
113 | if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) | |
114 | net_inc_ingress_queue(); | |
115 | #endif | |
d1c85c2e | 116 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 117 | static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]); |
a2d7ec58 | 118 | #endif |
f6ebe77f HW |
119 | return 0; |
120 | } | |
085db2c0 | 121 | EXPORT_SYMBOL(nf_register_net_hook); |
f6ebe77f | 122 | |
085db2c0 | 123 | void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg) |
f6ebe77f | 124 | { |
085db2c0 | 125 | struct list_head *nf_hook_list; |
7181ebaf | 126 | struct nf_hook_entry *entry; |
085db2c0 EB |
127 | struct nf_hook_ops *elem; |
128 | ||
129 | nf_hook_list = find_nf_hook_list(net, reg); | |
130 | if (!nf_hook_list) | |
131 | return; | |
132 | ||
fd706d69 | 133 | mutex_lock(&nf_hook_mutex); |
085db2c0 | 134 | list_for_each_entry(elem, nf_hook_list, list) { |
7181ebaf PNA |
135 | entry = container_of(elem, struct nf_hook_entry, ops); |
136 | if (entry->orig_ops == reg) { | |
137 | list_del_rcu(&entry->ops.list); | |
085db2c0 EB |
138 | break; |
139 | } | |
140 | } | |
fd706d69 | 141 | mutex_unlock(&nf_hook_mutex); |
085db2c0 EB |
142 | if (&elem->list == nf_hook_list) { |
143 | WARN(1, "nf_unregister_net_hook: hook not found!\n"); | |
144 | return; | |
145 | } | |
e687ad60 | 146 | #ifdef CONFIG_NETFILTER_INGRESS |
4c091156 EB |
147 | if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) |
148 | net_dec_ingress_queue(); | |
e687ad60 | 149 | #endif |
d1c85c2e | 150 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 151 | static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]); |
a2d7ec58 | 152 | #endif |
f6ebe77f | 153 | synchronize_net(); |
7181ebaf PNA |
154 | nf_queue_nf_hook_drop(net, &entry->ops); |
155 | kfree(entry); | |
085db2c0 EB |
156 | } |
157 | EXPORT_SYMBOL(nf_unregister_net_hook); | |
158 | ||
159 | int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, | |
160 | unsigned int n) | |
161 | { | |
162 | unsigned int i; | |
163 | int err = 0; | |
164 | ||
165 | for (i = 0; i < n; i++) { | |
166 | err = nf_register_net_hook(net, ®[i]); | |
167 | if (err) | |
168 | goto err; | |
169 | } | |
170 | return err; | |
171 | ||
172 | err: | |
173 | if (i > 0) | |
174 | nf_unregister_net_hooks(net, reg, i); | |
175 | return err; | |
176 | } | |
177 | EXPORT_SYMBOL(nf_register_net_hooks); | |
178 | ||
179 | void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, | |
180 | unsigned int n) | |
181 | { | |
182 | while (n-- > 0) | |
183 | nf_unregister_net_hook(net, ®[n]); | |
184 | } | |
185 | EXPORT_SYMBOL(nf_unregister_net_hooks); | |
186 | ||
187 | static LIST_HEAD(nf_hook_list); | |
188 | ||
189 | int nf_register_hook(struct nf_hook_ops *reg) | |
190 | { | |
191 | struct net *net, *last; | |
192 | int ret; | |
193 | ||
194 | rtnl_lock(); | |
195 | for_each_net(net) { | |
196 | ret = nf_register_net_hook(net, reg); | |
197 | if (ret && ret != -ENOENT) | |
198 | goto rollback; | |
199 | } | |
200 | list_add_tail(®->list, &nf_hook_list); | |
201 | rtnl_unlock(); | |
202 | ||
203 | return 0; | |
204 | rollback: | |
205 | last = net; | |
206 | for_each_net(net) { | |
207 | if (net == last) | |
208 | break; | |
209 | nf_unregister_net_hook(net, reg); | |
210 | } | |
211 | rtnl_unlock(); | |
212 | return ret; | |
213 | } | |
214 | EXPORT_SYMBOL(nf_register_hook); | |
215 | ||
216 | void nf_unregister_hook(struct nf_hook_ops *reg) | |
217 | { | |
218 | struct net *net; | |
219 | ||
220 | rtnl_lock(); | |
221 | list_del(®->list); | |
222 | for_each_net(net) | |
223 | nf_unregister_net_hook(net, reg); | |
224 | rtnl_unlock(); | |
f6ebe77f HW |
225 | } |
226 | EXPORT_SYMBOL(nf_unregister_hook); | |
227 | ||
972d1cb1 PM |
228 | int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n) |
229 | { | |
230 | unsigned int i; | |
231 | int err = 0; | |
232 | ||
233 | for (i = 0; i < n; i++) { | |
234 | err = nf_register_hook(®[i]); | |
235 | if (err) | |
236 | goto err; | |
237 | } | |
238 | return err; | |
239 | ||
240 | err: | |
241 | if (i > 0) | |
242 | nf_unregister_hooks(reg, i); | |
243 | return err; | |
244 | } | |
245 | EXPORT_SYMBOL(nf_register_hooks); | |
246 | ||
247 | void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n) | |
248 | { | |
f68c5301 CG |
249 | while (n-- > 0) |
250 | nf_unregister_hook(®[n]); | |
972d1cb1 PM |
251 | } |
252 | EXPORT_SYMBOL(nf_unregister_hooks); | |
253 | ||
f6ebe77f | 254 | unsigned int nf_iterate(struct list_head *head, |
3db05fea | 255 | struct sk_buff *skb, |
cfdfab31 DM |
256 | struct nf_hook_state *state, |
257 | struct nf_hook_ops **elemp) | |
f6ebe77f HW |
258 | { |
259 | unsigned int verdict; | |
260 | ||
261 | /* | |
262 | * The caller must not block between calls to this | |
263 | * function because of risk of continuing from deleted element. | |
264 | */ | |
2a6decfd | 265 | list_for_each_entry_continue_rcu((*elemp), head, list) { |
cfdfab31 | 266 | if (state->thresh > (*elemp)->priority) |
f6ebe77f HW |
267 | continue; |
268 | ||
269 | /* Optimization: we don't need to hold module | |
601e68e1 | 270 | reference here, since function can't sleep. --RR */ |
de9963f0 | 271 | repeat: |
238e54c9 | 272 | verdict = (*elemp)->hook(*elemp, skb, state); |
f6ebe77f HW |
273 | if (verdict != NF_ACCEPT) { |
274 | #ifdef CONFIG_NETFILTER_DEBUG | |
275 | if (unlikely((verdict & NF_VERDICT_MASK) | |
276 | > NF_MAX_VERDICT)) { | |
277 | NFDEBUG("Evil return from %p(%u).\n", | |
cfdfab31 | 278 | (*elemp)->hook, state->hook); |
f6ebe77f HW |
279 | continue; |
280 | } | |
281 | #endif | |
2a6decfd | 282 | if (verdict != NF_REPEAT) |
f6ebe77f | 283 | return verdict; |
de9963f0 | 284 | goto repeat; |
f6ebe77f HW |
285 | } |
286 | } | |
287 | return NF_ACCEPT; | |
288 | } | |
289 | ||
290 | ||
291 | /* Returns 1 if okfn() needs to be executed by the caller, | |
292 | * -EPERM for NF_DROP, 0 otherwise. */ | |
cfdfab31 | 293 | int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state) |
f6ebe77f | 294 | { |
2a6decfd | 295 | struct nf_hook_ops *elem; |
f6ebe77f HW |
296 | unsigned int verdict; |
297 | int ret = 0; | |
298 | ||
299 | /* We may already have this, but read-locks nest anyway */ | |
300 | rcu_read_lock(); | |
301 | ||
f7191483 | 302 | elem = list_entry_rcu(state->hook_list, struct nf_hook_ops, list); |
f6ebe77f | 303 | next_hook: |
f7191483 | 304 | verdict = nf_iterate(state->hook_list, skb, state, &elem); |
f6ebe77f HW |
305 | if (verdict == NF_ACCEPT || verdict == NF_STOP) { |
306 | ret = 1; | |
da683650 | 307 | } else if ((verdict & NF_VERDICT_MASK) == NF_DROP) { |
3db05fea | 308 | kfree_skb(skb); |
f615df76 | 309 | ret = NF_DROP_GETERR(verdict); |
da683650 EP |
310 | if (ret == 0) |
311 | ret = -EPERM; | |
f9c63990 | 312 | } else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) { |
cfdfab31 DM |
313 | int err = nf_queue(skb, elem, state, |
314 | verdict >> NF_VERDICT_QBITS); | |
563e1232 FW |
315 | if (err < 0) { |
316 | if (err == -ECANCELED) | |
06cdb634 | 317 | goto next_hook; |
563e1232 | 318 | if (err == -ESRCH && |
94b27cc3 FW |
319 | (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS)) |
320 | goto next_hook; | |
06cdb634 FW |
321 | kfree_skb(skb); |
322 | } | |
f6ebe77f | 323 | } |
f6ebe77f HW |
324 | rcu_read_unlock(); |
325 | return ret; | |
326 | } | |
327 | EXPORT_SYMBOL(nf_hook_slow); | |
328 | ||
329 | ||
37d41879 | 330 | int skb_make_writable(struct sk_buff *skb, unsigned int writable_len) |
f6ebe77f | 331 | { |
37d41879 | 332 | if (writable_len > skb->len) |
f6ebe77f HW |
333 | return 0; |
334 | ||
335 | /* Not exclusive use of packet? Must copy. */ | |
37d41879 HX |
336 | if (!skb_cloned(skb)) { |
337 | if (writable_len <= skb_headlen(skb)) | |
338 | return 1; | |
339 | } else if (skb_clone_writable(skb, writable_len)) | |
340 | return 1; | |
341 | ||
342 | if (writable_len <= skb_headlen(skb)) | |
343 | writable_len = 0; | |
344 | else | |
345 | writable_len -= skb_headlen(skb); | |
346 | ||
347 | return !!__pskb_pull_tail(skb, writable_len); | |
f6ebe77f HW |
348 | } |
349 | EXPORT_SYMBOL(skb_make_writable); | |
350 | ||
c0cd1156 | 351 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
f6ebe77f HW |
352 | /* This does not belong here, but locally generated errors need it if connection |
353 | tracking in use: without this, connection may not be in hash table, and hence | |
354 | manufactured ICMP or RST packets will not be associated with it. */ | |
312a0c16 PM |
355 | void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) |
356 | __rcu __read_mostly; | |
f6ebe77f HW |
357 | EXPORT_SYMBOL(ip_ct_attach); |
358 | ||
312a0c16 | 359 | void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb) |
f6ebe77f | 360 | { |
312a0c16 | 361 | void (*attach)(struct sk_buff *, const struct sk_buff *); |
f6ebe77f | 362 | |
c3a47ab3 PM |
363 | if (skb->nfct) { |
364 | rcu_read_lock(); | |
365 | attach = rcu_dereference(ip_ct_attach); | |
366 | if (attach) | |
367 | attach(new, skb); | |
368 | rcu_read_unlock(); | |
f6ebe77f HW |
369 | } |
370 | } | |
371 | EXPORT_SYMBOL(nf_ct_attach); | |
de6e05c4 | 372 | |
0e60ebe0 | 373 | void (*nf_ct_destroy)(struct nf_conntrack *) __rcu __read_mostly; |
de6e05c4 YK |
374 | EXPORT_SYMBOL(nf_ct_destroy); |
375 | ||
376 | void nf_conntrack_destroy(struct nf_conntrack *nfct) | |
377 | { | |
378 | void (*destroy)(struct nf_conntrack *); | |
379 | ||
380 | rcu_read_lock(); | |
381 | destroy = rcu_dereference(nf_ct_destroy); | |
382 | BUG_ON(destroy == NULL); | |
383 | destroy(nfct); | |
384 | rcu_read_unlock(); | |
385 | } | |
386 | EXPORT_SYMBOL(nf_conntrack_destroy); | |
9cb01766 | 387 | |
5a05fae5 | 388 | struct nfq_ct_hook __rcu *nfq_ct_hook __read_mostly; |
9cb01766 PNA |
389 | EXPORT_SYMBOL_GPL(nfq_ct_hook); |
390 | ||
d584a61a PNA |
391 | struct nfq_ct_nat_hook __rcu *nfq_ct_nat_hook __read_mostly; |
392 | EXPORT_SYMBOL_GPL(nfq_ct_nat_hook); | |
393 | ||
de6e05c4 | 394 | #endif /* CONFIG_NF_CONNTRACK */ |
f6ebe77f | 395 | |
c7232c99 PM |
396 | #ifdef CONFIG_NF_NAT_NEEDED |
397 | void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *); | |
398 | EXPORT_SYMBOL(nf_nat_decode_session_hook); | |
399 | #endif | |
400 | ||
085db2c0 EB |
401 | static int nf_register_hook_list(struct net *net) |
402 | { | |
403 | struct nf_hook_ops *elem; | |
404 | int ret; | |
405 | ||
406 | rtnl_lock(); | |
407 | list_for_each_entry(elem, &nf_hook_list, list) { | |
408 | ret = nf_register_net_hook(net, elem); | |
409 | if (ret && ret != -ENOENT) | |
410 | goto out_undo; | |
411 | } | |
412 | rtnl_unlock(); | |
413 | return 0; | |
414 | ||
415 | out_undo: | |
416 | list_for_each_entry_continue_reverse(elem, &nf_hook_list, list) | |
417 | nf_unregister_net_hook(net, elem); | |
418 | rtnl_unlock(); | |
419 | return ret; | |
420 | } | |
421 | ||
422 | static void nf_unregister_hook_list(struct net *net) | |
423 | { | |
424 | struct nf_hook_ops *elem; | |
425 | ||
426 | rtnl_lock(); | |
427 | list_for_each_entry(elem, &nf_hook_list, list) | |
428 | nf_unregister_net_hook(net, elem); | |
429 | rtnl_unlock(); | |
430 | } | |
431 | ||
f3c1a44a G |
432 | static int __net_init netfilter_net_init(struct net *net) |
433 | { | |
085db2c0 EB |
434 | int i, h, ret; |
435 | ||
436 | for (i = 0; i < ARRAY_SIZE(net->nf.hooks); i++) { | |
437 | for (h = 0; h < NF_MAX_HOOKS; h++) | |
438 | INIT_LIST_HEAD(&net->nf.hooks[i][h]); | |
439 | } | |
440 | ||
f3c1a44a G |
441 | #ifdef CONFIG_PROC_FS |
442 | net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter", | |
443 | net->proc_net); | |
12202fa7 PNA |
444 | if (!net->nf.proc_netfilter) { |
445 | if (!net_eq(net, &init_net)) | |
446 | pr_err("cannot create netfilter proc entry"); | |
447 | ||
f3c1a44a G |
448 | return -ENOMEM; |
449 | } | |
450 | #endif | |
085db2c0 EB |
451 | ret = nf_register_hook_list(net); |
452 | if (ret) | |
453 | remove_proc_entry("netfilter", net->proc_net); | |
454 | ||
455 | return ret; | |
f3c1a44a G |
456 | } |
457 | ||
458 | static void __net_exit netfilter_net_exit(struct net *net) | |
459 | { | |
085db2c0 | 460 | nf_unregister_hook_list(net); |
f3c1a44a G |
461 | remove_proc_entry("netfilter", net->proc_net); |
462 | } | |
463 | ||
464 | static struct pernet_operations netfilter_net_ops = { | |
465 | .init = netfilter_net_init, | |
466 | .exit = netfilter_net_exit, | |
467 | }; | |
468 | ||
6d11cfdb | 469 | int __init netfilter_init(void) |
f6ebe77f | 470 | { |
085db2c0 | 471 | int ret; |
f6ebe77f | 472 | |
6d11cfdb PNA |
473 | ret = register_pernet_subsys(&netfilter_net_ops); |
474 | if (ret < 0) | |
475 | goto err; | |
476 | ||
477 | ret = netfilter_log_init(); | |
478 | if (ret < 0) | |
479 | goto err_pernet; | |
f6ebe77f | 480 | |
6d11cfdb PNA |
481 | return 0; |
482 | err_pernet: | |
483 | unregister_pernet_subsys(&netfilter_net_ops); | |
484 | err: | |
485 | return ret; | |
f6ebe77f | 486 | } |