1 | /* netfilter.c: look after the filters for various protocols. |
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 | * This code is GPL. |
8 | */ |
9 | #include <linux/kernel.h> |
10 | #include <linux/netfilter.h> |
11 | #include <net/protocol.h> |
12 | #include <linux/init.h> |
13 | #include <linux/skbuff.h> |
14 | #include <linux/wait.h> |
15 | #include <linux/module.h> |
16 | #include <linux/interrupt.h> |
17 | #include <linux/if.h> |
18 | #include <linux/netdevice.h> |
19 | #include <linux/netfilter_ipv6.h> |
20 | #include <linux/inetdevice.h> |
21 | #include <linux/proc_fs.h> |
22 | #include <linux/mutex.h> |
23 | #include <linux/mm.h> |
24 | #include <linux/rcupdate.h> |
25 | #include <net/net_namespace.h> |
26 | #include <net/netfilter/nf_queue.h> |
27 | #include <net/sock.h> |
28 | |
29 | #include "nf_internals.h" |
30 | |
31 | const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly; |
32 | EXPORT_SYMBOL_GPL(nf_ipv6_ops); |
33 | |
34 | DEFINE_PER_CPU(bool, nf_skb_duplicated); |
35 | EXPORT_SYMBOL_GPL(nf_skb_duplicated); |
36 | |
37 | #ifdef CONFIG_JUMP_LABEL |
38 | struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; |
39 | EXPORT_SYMBOL(nf_hooks_needed); |
40 | #endif |
41 | |
42 | static DEFINE_MUTEX(nf_hook_mutex); |
43 | |
44 | /* max hooks per family/hooknum */ |
45 | #define MAX_HOOK_COUNT 1024 |
46 | |
47 | #define nf_entry_dereference(e) \ |
48 | rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex)) |
49 | |
50 | static struct nf_hook_entries *allocate_hook_entries_size(u16 num) |
51 | { |
52 | struct nf_hook_entries *e; |
53 | size_t alloc = sizeof(*e) + |
54 | sizeof(struct nf_hook_entry) * num + |
55 | sizeof(struct nf_hook_ops *) * num + |
56 | sizeof(struct nf_hook_entries_rcu_head); |
57 | |
58 | if (num == 0) |
59 | return NULL; |
60 | |
61 | e = kvzalloc(size: alloc, GFP_KERNEL_ACCOUNT); |
62 | if (e) |
63 | e->num_hook_entries = num; |
64 | return e; |
65 | } |
66 | |
67 | static void __nf_hook_entries_free(struct rcu_head *h) |
68 | { |
69 | struct nf_hook_entries_rcu_head *head; |
70 | |
71 | head = container_of(h, struct nf_hook_entries_rcu_head, head); |
72 | kvfree(addr: head->allocation); |
73 | } |
74 | |
75 | static void nf_hook_entries_free(struct nf_hook_entries *e) |
76 | { |
77 | struct nf_hook_entries_rcu_head *head; |
78 | struct nf_hook_ops **ops; |
79 | unsigned int num; |
80 | |
81 | if (!e) |
82 | return; |
83 | |
84 | num = e->num_hook_entries; |
85 | ops = nf_hook_entries_get_hook_ops(e); |
86 | head = (void *)&ops[num]; |
87 | head->allocation = e; |
88 | call_rcu(head: &head->head, func: __nf_hook_entries_free); |
89 | } |
90 | |
91 | static unsigned int accept_all(void *priv, |
92 | struct sk_buff *skb, |
93 | const struct nf_hook_state *state) |
94 | { |
95 | return NF_ACCEPT; /* ACCEPT makes nf_hook_slow call next hook */ |
96 | } |
97 | |
98 | static const struct nf_hook_ops dummy_ops = { |
99 | .hook = accept_all, |
100 | .priority = INT_MIN, |
101 | }; |
102 | |
103 | static struct nf_hook_entries * |
104 | nf_hook_entries_grow(const struct nf_hook_entries *old, |
105 | const struct nf_hook_ops *reg) |
106 | { |
107 | unsigned int i, alloc_entries, nhooks, old_entries; |
108 | struct nf_hook_ops **orig_ops = NULL; |
109 | struct nf_hook_ops **new_ops; |
110 | struct nf_hook_entries *new; |
111 | bool inserted = false; |
112 | |
113 | alloc_entries = 1; |
114 | old_entries = old ? old->num_hook_entries : 0; |
115 | |
116 | if (old) { |
117 | orig_ops = nf_hook_entries_get_hook_ops(e: old); |
118 | |
119 | for (i = 0; i < old_entries; i++) { |
120 | if (orig_ops[i] != &dummy_ops) |
121 | alloc_entries++; |
122 | |
123 | /* Restrict BPF hook type to force a unique priority, not |
124 | * shared at attach time. |
125 | * |
126 | * This is mainly to avoid ordering issues between two |
127 | * different bpf programs, this doesn't prevent a normal |
128 | * hook at same priority as a bpf one (we don't want to |
129 | * prevent defrag, conntrack, iptables etc from attaching). |
130 | */ |
131 | if (reg->priority == orig_ops[i]->priority && |
132 | reg->hook_ops_type == NF_HOOK_OP_BPF) |
133 | return ERR_PTR(error: -EBUSY); |
134 | } |
135 | } |
136 | |
137 | if (alloc_entries > MAX_HOOK_COUNT) |
138 | return ERR_PTR(error: -E2BIG); |
139 | |
140 | new = allocate_hook_entries_size(num: alloc_entries); |
141 | if (!new) |
142 | return ERR_PTR(error: -ENOMEM); |
143 | |
144 | new_ops = nf_hook_entries_get_hook_ops(e: new); |
145 | |
146 | i = 0; |
147 | nhooks = 0; |
148 | while (i < old_entries) { |
149 | if (orig_ops[i] == &dummy_ops) { |
150 | ++i; |
151 | continue; |
152 | } |
153 | |
154 | if (inserted || reg->priority > orig_ops[i]->priority) { |
155 | new_ops[nhooks] = (void *)orig_ops[i]; |
156 | new->hooks[nhooks] = old->hooks[i]; |
157 | i++; |
158 | } else { |
159 | new_ops[nhooks] = (void *)reg; |
160 | new->hooks[nhooks].hook = reg->hook; |
161 | new->hooks[nhooks].priv = reg->priv; |
162 | inserted = true; |
163 | } |
164 | nhooks++; |
165 | } |
166 | |
167 | if (!inserted) { |
168 | new_ops[nhooks] = (void *)reg; |
169 | new->hooks[nhooks].hook = reg->hook; |
170 | new->hooks[nhooks].priv = reg->priv; |
171 | } |
172 | |
173 | return new; |
174 | } |
175 | |
176 | static void hooks_validate(const struct nf_hook_entries *hooks) |
177 | { |
178 | #ifdef CONFIG_DEBUG_MISC |
179 | struct nf_hook_ops **orig_ops; |
180 | int prio = INT_MIN; |
181 | size_t i = 0; |
182 | |
183 | orig_ops = nf_hook_entries_get_hook_ops(e: hooks); |
184 | |
185 | for (i = 0; i < hooks->num_hook_entries; i++) { |
186 | if (orig_ops[i] == &dummy_ops) |
187 | continue; |
188 | |
189 | WARN_ON(orig_ops[i]->priority < prio); |
190 | |
191 | if (orig_ops[i]->priority > prio) |
192 | prio = orig_ops[i]->priority; |
193 | } |
194 | #endif |
195 | } |
196 | |
197 | int nf_hook_entries_insert_raw(struct nf_hook_entries __rcu **pp, |
198 | const struct nf_hook_ops *reg) |
199 | { |
200 | struct nf_hook_entries *new_hooks; |
201 | struct nf_hook_entries *p; |
202 | |
203 | p = rcu_dereference_raw(*pp); |
204 | new_hooks = nf_hook_entries_grow(old: p, reg); |
205 | if (IS_ERR(ptr: new_hooks)) |
206 | return PTR_ERR(ptr: new_hooks); |
207 | |
208 | hooks_validate(hooks: new_hooks); |
209 | |
210 | rcu_assign_pointer(*pp, new_hooks); |
211 | |
212 | BUG_ON(p == new_hooks); |
213 | nf_hook_entries_free(e: p); |
214 | return 0; |
215 | } |
216 | EXPORT_SYMBOL_GPL(nf_hook_entries_insert_raw); |
217 | |
218 | /* |
219 | * __nf_hook_entries_try_shrink - try to shrink hook array |
220 | * |
221 | * @old -- current hook blob at @pp |
222 | * @pp -- location of hook blob |
223 | * |
224 | * Hook unregistration must always succeed, so to-be-removed hooks |
225 | * are replaced by a dummy one that will just move to next hook. |
226 | * |
227 | * This counts the current dummy hooks, attempts to allocate new blob, |
228 | * copies the live hooks, then replaces and discards old one. |
229 | * |
230 | * return values: |
231 | * |
232 | * Returns address to free, or NULL. |
233 | */ |
234 | static void *__nf_hook_entries_try_shrink(struct nf_hook_entries *old, |
235 | struct nf_hook_entries __rcu **pp) |
236 | { |
237 | unsigned int i, j, skip = 0, hook_entries; |
238 | struct nf_hook_entries *new = NULL; |
239 | struct nf_hook_ops **orig_ops; |
240 | struct nf_hook_ops **new_ops; |
241 | |
242 | if (WARN_ON_ONCE(!old)) |
243 | return NULL; |
244 | |
245 | orig_ops = nf_hook_entries_get_hook_ops(e: old); |
246 | for (i = 0; i < old->num_hook_entries; i++) { |
247 | if (orig_ops[i] == &dummy_ops) |
248 | skip++; |
249 | } |
250 | |
251 | /* if skip == hook_entries all hooks have been removed */ |
252 | hook_entries = old->num_hook_entries; |
253 | if (skip == hook_entries) |
254 | goto out_assign; |
255 | |
256 | if (skip == 0) |
257 | return NULL; |
258 | |
259 | hook_entries -= skip; |
260 | new = allocate_hook_entries_size(num: hook_entries); |
261 | if (!new) |
262 | return NULL; |
263 | |
264 | new_ops = nf_hook_entries_get_hook_ops(e: new); |
265 | for (i = 0, j = 0; i < old->num_hook_entries; i++) { |
266 | if (orig_ops[i] == &dummy_ops) |
267 | continue; |
268 | new->hooks[j] = old->hooks[i]; |
269 | new_ops[j] = (void *)orig_ops[i]; |
270 | j++; |
271 | } |
272 | hooks_validate(hooks: new); |
273 | out_assign: |
274 | rcu_assign_pointer(*pp, new); |
275 | return old; |
276 | } |
277 | |
278 | static struct nf_hook_entries __rcu ** |
279 | nf_hook_entry_head(struct net *net, int pf, unsigned int hooknum, |
280 | struct net_device *dev) |
281 | { |
282 | switch (pf) { |
283 | case NFPROTO_NETDEV: |
284 | break; |
285 | #ifdef CONFIG_NETFILTER_FAMILY_ARP |
286 | case NFPROTO_ARP: |
287 | if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_arp) <= hooknum)) |
288 | return NULL; |
289 | return net->nf.hooks_arp + hooknum; |
290 | #endif |
291 | #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE |
292 | case NFPROTO_BRIDGE: |
293 | if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_bridge) <= hooknum)) |
294 | return NULL; |
295 | return net->nf.hooks_bridge + hooknum; |
296 | #endif |
297 | #ifdef CONFIG_NETFILTER_INGRESS |
298 | case NFPROTO_INET: |
299 | if (WARN_ON_ONCE(hooknum != NF_INET_INGRESS)) |
300 | return NULL; |
301 | if (!dev || dev_net(dev) != net) { |
302 | WARN_ON_ONCE(1); |
303 | return NULL; |
304 | } |
305 | return &dev->nf_hooks_ingress; |
306 | #endif |
307 | case NFPROTO_IPV4: |
308 | if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv4) <= hooknum)) |
309 | return NULL; |
310 | return net->nf.hooks_ipv4 + hooknum; |
311 | case NFPROTO_IPV6: |
312 | if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv6) <= hooknum)) |
313 | return NULL; |
314 | return net->nf.hooks_ipv6 + hooknum; |
315 | default: |
316 | WARN_ON_ONCE(1); |
317 | return NULL; |
318 | } |
319 | |
320 | #ifdef CONFIG_NETFILTER_INGRESS |
321 | if (hooknum == NF_NETDEV_INGRESS) { |
322 | if (dev && dev_net(dev) == net) |
323 | return &dev->nf_hooks_ingress; |
324 | } |
325 | #endif |
326 | #ifdef CONFIG_NETFILTER_EGRESS |
327 | if (hooknum == NF_NETDEV_EGRESS) { |
328 | if (dev && dev_net(dev) == net) |
329 | return &dev->nf_hooks_egress; |
330 | } |
331 | #endif |
332 | WARN_ON_ONCE(1); |
333 | return NULL; |
334 | } |
335 | |
336 | static int nf_ingress_check(struct net *net, const struct nf_hook_ops *reg, |
337 | int hooknum) |
338 | { |
339 | #ifndef CONFIG_NETFILTER_INGRESS |
340 | if (reg->hooknum == hooknum) |
341 | return -EOPNOTSUPP; |
342 | #endif |
343 | if (reg->hooknum != hooknum || |
344 | !reg->dev || dev_net(dev: reg->dev) != net) |
345 | return -EINVAL; |
346 | |
347 | return 0; |
348 | } |
349 | |
350 | static inline bool __maybe_unused nf_ingress_hook(const struct nf_hook_ops *reg, |
351 | int pf) |
352 | { |
353 | if ((pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) || |
354 | (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS)) |
355 | return true; |
356 | |
357 | return false; |
358 | } |
359 | |
360 | static inline bool __maybe_unused nf_egress_hook(const struct nf_hook_ops *reg, |
361 | int pf) |
362 | { |
363 | return pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_EGRESS; |
364 | } |
365 | |
366 | static void nf_static_key_inc(const struct nf_hook_ops *reg, int pf) |
367 | { |
368 | #ifdef CONFIG_JUMP_LABEL |
369 | int hooknum; |
370 | |
371 | if (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS) { |
372 | pf = NFPROTO_NETDEV; |
373 | hooknum = NF_NETDEV_INGRESS; |
374 | } else { |
375 | hooknum = reg->hooknum; |
376 | } |
377 | static_key_slow_inc(key: &nf_hooks_needed[pf][hooknum]); |
378 | #endif |
379 | } |
380 | |
381 | static void nf_static_key_dec(const struct nf_hook_ops *reg, int pf) |
382 | { |
383 | #ifdef CONFIG_JUMP_LABEL |
384 | int hooknum; |
385 | |
386 | if (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS) { |
387 | pf = NFPROTO_NETDEV; |
388 | hooknum = NF_NETDEV_INGRESS; |
389 | } else { |
390 | hooknum = reg->hooknum; |
391 | } |
392 | static_key_slow_dec(key: &nf_hooks_needed[pf][hooknum]); |
393 | #endif |
394 | } |
395 | |
396 | static int __nf_register_net_hook(struct net *net, int pf, |
397 | const struct nf_hook_ops *reg) |
398 | { |
399 | struct nf_hook_entries *p, *new_hooks; |
400 | struct nf_hook_entries __rcu **pp; |
401 | int err; |
402 | |
403 | switch (pf) { |
404 | case NFPROTO_NETDEV: |
405 | #ifndef CONFIG_NETFILTER_INGRESS |
406 | if (reg->hooknum == NF_NETDEV_INGRESS) |
407 | return -EOPNOTSUPP; |
408 | #endif |
409 | #ifndef CONFIG_NETFILTER_EGRESS |
410 | if (reg->hooknum == NF_NETDEV_EGRESS) |
411 | return -EOPNOTSUPP; |
412 | #endif |
413 | if ((reg->hooknum != NF_NETDEV_INGRESS && |
414 | reg->hooknum != NF_NETDEV_EGRESS) || |
415 | !reg->dev || dev_net(dev: reg->dev) != net) |
416 | return -EINVAL; |
417 | break; |
418 | case NFPROTO_INET: |
419 | if (reg->hooknum != NF_INET_INGRESS) |
420 | break; |
421 | |
422 | err = nf_ingress_check(net, reg, hooknum: NF_INET_INGRESS); |
423 | if (err < 0) |
424 | return err; |
425 | break; |
426 | } |
427 | |
428 | pp = nf_hook_entry_head(net, pf, hooknum: reg->hooknum, dev: reg->dev); |
429 | if (!pp) |
430 | return -EINVAL; |
431 | |
432 | mutex_lock(&nf_hook_mutex); |
433 | |
434 | p = nf_entry_dereference(*pp); |
435 | new_hooks = nf_hook_entries_grow(old: p, reg); |
436 | |
437 | if (!IS_ERR(ptr: new_hooks)) { |
438 | hooks_validate(hooks: new_hooks); |
439 | rcu_assign_pointer(*pp, new_hooks); |
440 | } |
441 | |
442 | mutex_unlock(lock: &nf_hook_mutex); |
443 | if (IS_ERR(ptr: new_hooks)) |
444 | return PTR_ERR(ptr: new_hooks); |
445 | |
446 | #ifdef CONFIG_NETFILTER_INGRESS |
447 | if (nf_ingress_hook(reg, pf)) |
448 | net_inc_ingress_queue(); |
449 | #endif |
450 | #ifdef CONFIG_NETFILTER_EGRESS |
451 | if (nf_egress_hook(reg, pf)) |
452 | net_inc_egress_queue(); |
453 | #endif |
454 | nf_static_key_inc(reg, pf); |
455 | |
456 | BUG_ON(p == new_hooks); |
457 | nf_hook_entries_free(e: p); |
458 | return 0; |
459 | } |
460 | |
461 | /* |
462 | * nf_remove_net_hook - remove a hook from blob |
463 | * |
464 | * @oldp: current address of hook blob |
465 | * @unreg: hook to unregister |
466 | * |
467 | * This cannot fail, hook unregistration must always succeed. |
468 | * Therefore replace the to-be-removed hook with a dummy hook. |
469 | */ |
470 | static bool nf_remove_net_hook(struct nf_hook_entries *old, |
471 | const struct nf_hook_ops *unreg) |
472 | { |
473 | struct nf_hook_ops **orig_ops; |
474 | unsigned int i; |
475 | |
476 | orig_ops = nf_hook_entries_get_hook_ops(e: old); |
477 | for (i = 0; i < old->num_hook_entries; i++) { |
478 | if (orig_ops[i] != unreg) |
479 | continue; |
480 | WRITE_ONCE(old->hooks[i].hook, accept_all); |
481 | WRITE_ONCE(orig_ops[i], (void *)&dummy_ops); |
482 | return true; |
483 | } |
484 | |
485 | return false; |
486 | } |
487 | |
488 | static void __nf_unregister_net_hook(struct net *net, int pf, |
489 | const struct nf_hook_ops *reg) |
490 | { |
491 | struct nf_hook_entries __rcu **pp; |
492 | struct nf_hook_entries *p; |
493 | |
494 | pp = nf_hook_entry_head(net, pf, hooknum: reg->hooknum, dev: reg->dev); |
495 | if (!pp) |
496 | return; |
497 | |
498 | mutex_lock(&nf_hook_mutex); |
499 | |
500 | p = nf_entry_dereference(*pp); |
501 | if (WARN_ON_ONCE(!p)) { |
502 | mutex_unlock(lock: &nf_hook_mutex); |
503 | return; |
504 | } |
505 | |
506 | if (nf_remove_net_hook(old: p, unreg: reg)) { |
507 | #ifdef CONFIG_NETFILTER_INGRESS |
508 | if (nf_ingress_hook(reg, pf)) |
509 | net_dec_ingress_queue(); |
510 | #endif |
511 | #ifdef CONFIG_NETFILTER_EGRESS |
512 | if (nf_egress_hook(reg, pf)) |
513 | net_dec_egress_queue(); |
514 | #endif |
515 | nf_static_key_dec(reg, pf); |
516 | } else { |
517 | WARN_ONCE(1, "hook not found, pf %d num %d" , pf, reg->hooknum); |
518 | } |
519 | |
520 | p = __nf_hook_entries_try_shrink(old: p, pp); |
521 | mutex_unlock(lock: &nf_hook_mutex); |
522 | if (!p) |
523 | return; |
524 | |
525 | nf_queue_nf_hook_drop(net); |
526 | nf_hook_entries_free(e: p); |
527 | } |
528 | |
529 | void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg) |
530 | { |
531 | if (reg->pf == NFPROTO_INET) { |
532 | if (reg->hooknum == NF_INET_INGRESS) { |
533 | __nf_unregister_net_hook(net, pf: NFPROTO_INET, reg); |
534 | } else { |
535 | __nf_unregister_net_hook(net, pf: NFPROTO_IPV4, reg); |
536 | __nf_unregister_net_hook(net, pf: NFPROTO_IPV6, reg); |
537 | } |
538 | } else { |
539 | __nf_unregister_net_hook(net, pf: reg->pf, reg); |
540 | } |
541 | } |
542 | EXPORT_SYMBOL(nf_unregister_net_hook); |
543 | |
544 | void nf_hook_entries_delete_raw(struct nf_hook_entries __rcu **pp, |
545 | const struct nf_hook_ops *reg) |
546 | { |
547 | struct nf_hook_entries *p; |
548 | |
549 | p = rcu_dereference_raw(*pp); |
550 | if (nf_remove_net_hook(old: p, unreg: reg)) { |
551 | p = __nf_hook_entries_try_shrink(old: p, pp); |
552 | nf_hook_entries_free(e: p); |
553 | } |
554 | } |
555 | EXPORT_SYMBOL_GPL(nf_hook_entries_delete_raw); |
556 | |
557 | int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) |
558 | { |
559 | int err; |
560 | |
561 | if (reg->pf == NFPROTO_INET) { |
562 | if (reg->hooknum == NF_INET_INGRESS) { |
563 | err = __nf_register_net_hook(net, pf: NFPROTO_INET, reg); |
564 | if (err < 0) |
565 | return err; |
566 | } else { |
567 | err = __nf_register_net_hook(net, pf: NFPROTO_IPV4, reg); |
568 | if (err < 0) |
569 | return err; |
570 | |
571 | err = __nf_register_net_hook(net, pf: NFPROTO_IPV6, reg); |
572 | if (err < 0) { |
573 | __nf_unregister_net_hook(net, pf: NFPROTO_IPV4, reg); |
574 | return err; |
575 | } |
576 | } |
577 | } else { |
578 | err = __nf_register_net_hook(net, pf: reg->pf, reg); |
579 | if (err < 0) |
580 | return err; |
581 | } |
582 | |
583 | return 0; |
584 | } |
585 | EXPORT_SYMBOL(nf_register_net_hook); |
586 | |
587 | int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, |
588 | unsigned int n) |
589 | { |
590 | unsigned int i; |
591 | int err = 0; |
592 | |
593 | for (i = 0; i < n; i++) { |
594 | err = nf_register_net_hook(net, ®[i]); |
595 | if (err) |
596 | goto err; |
597 | } |
598 | return err; |
599 | |
600 | err: |
601 | if (i > 0) |
602 | nf_unregister_net_hooks(net, reg, n: i); |
603 | return err; |
604 | } |
605 | EXPORT_SYMBOL(nf_register_net_hooks); |
606 | |
607 | void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, |
608 | unsigned int hookcount) |
609 | { |
610 | unsigned int i; |
611 | |
612 | for (i = 0; i < hookcount; i++) |
613 | nf_unregister_net_hook(net, ®[i]); |
614 | } |
615 | EXPORT_SYMBOL(nf_unregister_net_hooks); |
616 | |
617 | /* Returns 1 if okfn() needs to be executed by the caller, |
618 | * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */ |
619 | int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, |
620 | const struct nf_hook_entries *e, unsigned int s) |
621 | { |
622 | unsigned int verdict; |
623 | int ret; |
624 | |
625 | for (; s < e->num_hook_entries; s++) { |
626 | verdict = nf_hook_entry_hookfn(entry: &e->hooks[s], skb, state); |
627 | switch (verdict & NF_VERDICT_MASK) { |
628 | case NF_ACCEPT: |
629 | break; |
630 | case NF_DROP: |
631 | kfree_skb_reason(skb, |
632 | reason: SKB_DROP_REASON_NETFILTER_DROP); |
633 | ret = NF_DROP_GETERR(verdict); |
634 | if (ret == 0) |
635 | ret = -EPERM; |
636 | return ret; |
637 | case NF_QUEUE: |
638 | ret = nf_queue(skb, state, index: s, verdict); |
639 | if (ret == 1) |
640 | continue; |
641 | return ret; |
642 | case NF_STOLEN: |
643 | return NF_DROP_GETERR(verdict); |
644 | default: |
645 | WARN_ON_ONCE(1); |
646 | return 0; |
647 | } |
648 | } |
649 | |
650 | return 1; |
651 | } |
652 | EXPORT_SYMBOL(nf_hook_slow); |
653 | |
654 | void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state, |
655 | const struct nf_hook_entries *e) |
656 | { |
657 | struct sk_buff *skb, *next; |
658 | struct list_head sublist; |
659 | int ret; |
660 | |
661 | INIT_LIST_HEAD(list: &sublist); |
662 | |
663 | list_for_each_entry_safe(skb, next, head, list) { |
664 | skb_list_del_init(skb); |
665 | ret = nf_hook_slow(skb, state, e, 0); |
666 | if (ret == 1) |
667 | list_add_tail(new: &skb->list, head: &sublist); |
668 | } |
669 | /* Put passed packets back on main list */ |
670 | list_splice(list: &sublist, head); |
671 | } |
672 | EXPORT_SYMBOL(nf_hook_slow_list); |
673 | |
674 | /* This needs to be compiled in any case to avoid dependencies between the |
675 | * nfnetlink_queue code and nf_conntrack. |
676 | */ |
677 | const struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly; |
678 | EXPORT_SYMBOL_GPL(nfnl_ct_hook); |
679 | |
680 | const struct nf_ct_hook __rcu *nf_ct_hook __read_mostly; |
681 | EXPORT_SYMBOL_GPL(nf_ct_hook); |
682 | |
683 | const struct nf_defrag_hook __rcu *nf_defrag_v4_hook __read_mostly; |
684 | EXPORT_SYMBOL_GPL(nf_defrag_v4_hook); |
685 | |
686 | const struct nf_defrag_hook __rcu *nf_defrag_v6_hook __read_mostly; |
687 | EXPORT_SYMBOL_GPL(nf_defrag_v6_hook); |
688 | |
689 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
690 | u8 nf_ctnetlink_has_listener; |
691 | EXPORT_SYMBOL_GPL(nf_ctnetlink_has_listener); |
692 | |
693 | const struct nf_nat_hook __rcu *nf_nat_hook __read_mostly; |
694 | EXPORT_SYMBOL_GPL(nf_nat_hook); |
695 | |
696 | /* This does not belong here, but locally generated errors need it if connection |
697 | * tracking in use: without this, connection may not be in hash table, and hence |
698 | * manufactured ICMP or RST packets will not be associated with it. |
699 | */ |
700 | void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb) |
701 | { |
702 | const struct nf_ct_hook *ct_hook; |
703 | |
704 | if (skb->_nfct) { |
705 | rcu_read_lock(); |
706 | ct_hook = rcu_dereference(nf_ct_hook); |
707 | if (ct_hook) |
708 | ct_hook->attach(new, skb); |
709 | rcu_read_unlock(); |
710 | } |
711 | } |
712 | EXPORT_SYMBOL(nf_ct_attach); |
713 | |
714 | void nf_conntrack_destroy(struct nf_conntrack *nfct) |
715 | { |
716 | const struct nf_ct_hook *ct_hook; |
717 | |
718 | rcu_read_lock(); |
719 | ct_hook = rcu_dereference(nf_ct_hook); |
720 | if (ct_hook) |
721 | ct_hook->destroy(nfct); |
722 | rcu_read_unlock(); |
723 | |
724 | WARN_ON(!ct_hook); |
725 | } |
726 | EXPORT_SYMBOL(nf_conntrack_destroy); |
727 | |
728 | void nf_ct_set_closing(struct nf_conntrack *nfct) |
729 | { |
730 | const struct nf_ct_hook *ct_hook; |
731 | |
732 | if (!nfct) |
733 | return; |
734 | |
735 | rcu_read_lock(); |
736 | ct_hook = rcu_dereference(nf_ct_hook); |
737 | if (ct_hook) |
738 | ct_hook->set_closing(nfct); |
739 | |
740 | rcu_read_unlock(); |
741 | } |
742 | EXPORT_SYMBOL_GPL(nf_ct_set_closing); |
743 | |
744 | bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, |
745 | const struct sk_buff *skb) |
746 | { |
747 | const struct nf_ct_hook *ct_hook; |
748 | bool ret = false; |
749 | |
750 | rcu_read_lock(); |
751 | ct_hook = rcu_dereference(nf_ct_hook); |
752 | if (ct_hook) |
753 | ret = ct_hook->get_tuple_skb(dst_tuple, skb); |
754 | rcu_read_unlock(); |
755 | return ret; |
756 | } |
757 | EXPORT_SYMBOL(nf_ct_get_tuple_skb); |
758 | |
759 | /* Built-in default zone used e.g. by modules. */ |
760 | const struct nf_conntrack_zone nf_ct_zone_dflt = { |
761 | .id = NF_CT_DEFAULT_ZONE_ID, |
762 | .dir = NF_CT_DEFAULT_ZONE_DIR, |
763 | }; |
764 | EXPORT_SYMBOL_GPL(nf_ct_zone_dflt); |
765 | #endif /* CONFIG_NF_CONNTRACK */ |
766 | |
767 | static void __net_init |
768 | __netfilter_net_init(struct nf_hook_entries __rcu **e, int max) |
769 | { |
770 | int h; |
771 | |
772 | for (h = 0; h < max; h++) |
773 | RCU_INIT_POINTER(e[h], NULL); |
774 | } |
775 | |
776 | static int __net_init netfilter_net_init(struct net *net) |
777 | { |
778 | __netfilter_net_init(e: net->nf.hooks_ipv4, ARRAY_SIZE(net->nf.hooks_ipv4)); |
779 | __netfilter_net_init(e: net->nf.hooks_ipv6, ARRAY_SIZE(net->nf.hooks_ipv6)); |
780 | #ifdef CONFIG_NETFILTER_FAMILY_ARP |
781 | __netfilter_net_init(e: net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp)); |
782 | #endif |
783 | #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE |
784 | __netfilter_net_init(e: net->nf.hooks_bridge, ARRAY_SIZE(net->nf.hooks_bridge)); |
785 | #endif |
786 | #ifdef CONFIG_PROC_FS |
787 | net->nf.proc_netfilter = proc_net_mkdir(net, name: "netfilter" , |
788 | parent: net->proc_net); |
789 | if (!net->nf.proc_netfilter) { |
790 | if (!net_eq(net1: net, net2: &init_net)) |
791 | pr_err("cannot create netfilter proc entry" ); |
792 | |
793 | return -ENOMEM; |
794 | } |
795 | #endif |
796 | |
797 | return 0; |
798 | } |
799 | |
800 | static void __net_exit netfilter_net_exit(struct net *net) |
801 | { |
802 | remove_proc_entry("netfilter" , net->proc_net); |
803 | } |
804 | |
805 | static struct pernet_operations netfilter_net_ops = { |
806 | .init = netfilter_net_init, |
807 | .exit = netfilter_net_exit, |
808 | }; |
809 | |
810 | int __init netfilter_init(void) |
811 | { |
812 | int ret; |
813 | |
814 | ret = register_pernet_subsys(&netfilter_net_ops); |
815 | if (ret < 0) |
816 | goto err; |
817 | |
818 | ret = netfilter_log_init(); |
819 | if (ret < 0) |
820 | goto err_pernet; |
821 | |
822 | return 0; |
823 | err_pernet: |
824 | unregister_pernet_subsys(&netfilter_net_ops); |
825 | err: |
826 | return ret; |
827 | } |
828 | |