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 | |
1e796fda | 37 | int nf_register_afinfo(const struct nf_afinfo *afinfo) |
bce8032e | 38 | { |
7926dbfa | 39 | mutex_lock(&afinfo_mutex); |
a9b3cd7f | 40 | RCU_INIT_POINTER(nf_afinfo[afinfo->family], afinfo); |
d486dd1f | 41 | mutex_unlock(&afinfo_mutex); |
bce8032e PM |
42 | return 0; |
43 | } | |
44 | EXPORT_SYMBOL_GPL(nf_register_afinfo); | |
45 | ||
1e796fda | 46 | void nf_unregister_afinfo(const struct nf_afinfo *afinfo) |
bce8032e | 47 | { |
d486dd1f | 48 | mutex_lock(&afinfo_mutex); |
a9b3cd7f | 49 | RCU_INIT_POINTER(nf_afinfo[afinfo->family], NULL); |
d486dd1f | 50 | mutex_unlock(&afinfo_mutex); |
bce8032e PM |
51 | synchronize_rcu(); |
52 | } | |
53 | EXPORT_SYMBOL_GPL(nf_unregister_afinfo); | |
54 | ||
7e9c6eeb | 55 | struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS] __read_mostly; |
f6ebe77f | 56 | EXPORT_SYMBOL(nf_hooks); |
a2d7ec58 | 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 HW |
64 | |
65 | int nf_register_hook(struct nf_hook_ops *reg) | |
66 | { | |
4c610979 | 67 | struct nf_hook_ops *elem; |
f6ebe77f | 68 | |
7926dbfa | 69 | mutex_lock(&nf_hook_mutex); |
4c610979 LZ |
70 | list_for_each_entry(elem, &nf_hooks[reg->pf][reg->hooknum], list) { |
71 | if (reg->priority < elem->priority) | |
f6ebe77f HW |
72 | break; |
73 | } | |
4c610979 | 74 | list_add_rcu(®->list, elem->list.prev); |
fd706d69 | 75 | mutex_unlock(&nf_hook_mutex); |
d1c85c2e | 76 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 77 | static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]); |
a2d7ec58 | 78 | #endif |
f6ebe77f HW |
79 | return 0; |
80 | } | |
81 | EXPORT_SYMBOL(nf_register_hook); | |
82 | ||
83 | void nf_unregister_hook(struct nf_hook_ops *reg) | |
84 | { | |
fd706d69 | 85 | mutex_lock(&nf_hook_mutex); |
f6ebe77f | 86 | list_del_rcu(®->list); |
fd706d69 | 87 | mutex_unlock(&nf_hook_mutex); |
d1c85c2e | 88 | #ifdef HAVE_JUMP_LABEL |
c5905afb | 89 | static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]); |
a2d7ec58 | 90 | #endif |
f6ebe77f HW |
91 | synchronize_net(); |
92 | } | |
93 | EXPORT_SYMBOL(nf_unregister_hook); | |
94 | ||
972d1cb1 PM |
95 | int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n) |
96 | { | |
97 | unsigned int i; | |
98 | int err = 0; | |
99 | ||
100 | for (i = 0; i < n; i++) { | |
101 | err = nf_register_hook(®[i]); | |
102 | if (err) | |
103 | goto err; | |
104 | } | |
105 | return err; | |
106 | ||
107 | err: | |
108 | if (i > 0) | |
109 | nf_unregister_hooks(reg, i); | |
110 | return err; | |
111 | } | |
112 | EXPORT_SYMBOL(nf_register_hooks); | |
113 | ||
114 | void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n) | |
115 | { | |
f68c5301 CG |
116 | while (n-- > 0) |
117 | nf_unregister_hook(®[n]); | |
972d1cb1 PM |
118 | } |
119 | EXPORT_SYMBOL(nf_unregister_hooks); | |
120 | ||
f6ebe77f | 121 | unsigned int nf_iterate(struct list_head *head, |
3db05fea | 122 | struct sk_buff *skb, |
cfdfab31 DM |
123 | struct nf_hook_state *state, |
124 | struct nf_hook_ops **elemp) | |
f6ebe77f HW |
125 | { |
126 | unsigned int verdict; | |
127 | ||
128 | /* | |
129 | * The caller must not block between calls to this | |
130 | * function because of risk of continuing from deleted element. | |
131 | */ | |
2a6decfd | 132 | list_for_each_entry_continue_rcu((*elemp), head, list) { |
cfdfab31 | 133 | if (state->thresh > (*elemp)->priority) |
f6ebe77f HW |
134 | continue; |
135 | ||
136 | /* Optimization: we don't need to hold module | |
601e68e1 | 137 | reference here, since function can't sleep. --RR */ |
de9963f0 | 138 | repeat: |
238e54c9 | 139 | verdict = (*elemp)->hook(*elemp, skb, state); |
f6ebe77f HW |
140 | if (verdict != NF_ACCEPT) { |
141 | #ifdef CONFIG_NETFILTER_DEBUG | |
142 | if (unlikely((verdict & NF_VERDICT_MASK) | |
143 | > NF_MAX_VERDICT)) { | |
144 | NFDEBUG("Evil return from %p(%u).\n", | |
cfdfab31 | 145 | (*elemp)->hook, state->hook); |
f6ebe77f HW |
146 | continue; |
147 | } | |
148 | #endif | |
2a6decfd | 149 | if (verdict != NF_REPEAT) |
f6ebe77f | 150 | return verdict; |
de9963f0 | 151 | goto repeat; |
f6ebe77f HW |
152 | } |
153 | } | |
154 | return NF_ACCEPT; | |
155 | } | |
156 | ||
157 | ||
158 | /* Returns 1 if okfn() needs to be executed by the caller, | |
159 | * -EPERM for NF_DROP, 0 otherwise. */ | |
cfdfab31 | 160 | int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state) |
f6ebe77f | 161 | { |
2a6decfd | 162 | struct nf_hook_ops *elem; |
f6ebe77f HW |
163 | unsigned int verdict; |
164 | int ret = 0; | |
165 | ||
166 | /* We may already have this, but read-locks nest anyway */ | |
167 | rcu_read_lock(); | |
168 | ||
cfdfab31 DM |
169 | elem = list_entry_rcu(&nf_hooks[state->pf][state->hook], |
170 | struct nf_hook_ops, list); | |
f6ebe77f | 171 | next_hook: |
cfdfab31 DM |
172 | verdict = nf_iterate(&nf_hooks[state->pf][state->hook], skb, state, |
173 | &elem); | |
f6ebe77f HW |
174 | if (verdict == NF_ACCEPT || verdict == NF_STOP) { |
175 | ret = 1; | |
da683650 | 176 | } else if ((verdict & NF_VERDICT_MASK) == NF_DROP) { |
3db05fea | 177 | kfree_skb(skb); |
f615df76 | 178 | ret = NF_DROP_GETERR(verdict); |
da683650 EP |
179 | if (ret == 0) |
180 | ret = -EPERM; | |
f9c63990 | 181 | } else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) { |
cfdfab31 DM |
182 | int err = nf_queue(skb, elem, state, |
183 | verdict >> NF_VERDICT_QBITS); | |
563e1232 FW |
184 | if (err < 0) { |
185 | if (err == -ECANCELED) | |
06cdb634 | 186 | goto next_hook; |
563e1232 | 187 | if (err == -ESRCH && |
94b27cc3 FW |
188 | (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS)) |
189 | goto next_hook; | |
06cdb634 FW |
190 | kfree_skb(skb); |
191 | } | |
f6ebe77f | 192 | } |
f6ebe77f HW |
193 | rcu_read_unlock(); |
194 | return ret; | |
195 | } | |
196 | EXPORT_SYMBOL(nf_hook_slow); | |
197 | ||
198 | ||
37d41879 | 199 | int skb_make_writable(struct sk_buff *skb, unsigned int writable_len) |
f6ebe77f | 200 | { |
37d41879 | 201 | if (writable_len > skb->len) |
f6ebe77f HW |
202 | return 0; |
203 | ||
204 | /* Not exclusive use of packet? Must copy. */ | |
37d41879 HX |
205 | if (!skb_cloned(skb)) { |
206 | if (writable_len <= skb_headlen(skb)) | |
207 | return 1; | |
208 | } else if (skb_clone_writable(skb, writable_len)) | |
209 | return 1; | |
210 | ||
211 | if (writable_len <= skb_headlen(skb)) | |
212 | writable_len = 0; | |
213 | else | |
214 | writable_len -= skb_headlen(skb); | |
215 | ||
216 | return !!__pskb_pull_tail(skb, writable_len); | |
f6ebe77f HW |
217 | } |
218 | EXPORT_SYMBOL(skb_make_writable); | |
219 | ||
c0cd1156 | 220 | #if IS_ENABLED(CONFIG_NF_CONNTRACK) |
f6ebe77f HW |
221 | /* This does not belong here, but locally generated errors need it if connection |
222 | tracking in use: without this, connection may not be in hash table, and hence | |
223 | manufactured ICMP or RST packets will not be associated with it. */ | |
312a0c16 PM |
224 | void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) |
225 | __rcu __read_mostly; | |
f6ebe77f HW |
226 | EXPORT_SYMBOL(ip_ct_attach); |
227 | ||
312a0c16 | 228 | void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb) |
f6ebe77f | 229 | { |
312a0c16 | 230 | void (*attach)(struct sk_buff *, const struct sk_buff *); |
f6ebe77f | 231 | |
c3a47ab3 PM |
232 | if (skb->nfct) { |
233 | rcu_read_lock(); | |
234 | attach = rcu_dereference(ip_ct_attach); | |
235 | if (attach) | |
236 | attach(new, skb); | |
237 | rcu_read_unlock(); | |
f6ebe77f HW |
238 | } |
239 | } | |
240 | EXPORT_SYMBOL(nf_ct_attach); | |
de6e05c4 | 241 | |
0e60ebe0 | 242 | void (*nf_ct_destroy)(struct nf_conntrack *) __rcu __read_mostly; |
de6e05c4 YK |
243 | EXPORT_SYMBOL(nf_ct_destroy); |
244 | ||
245 | void nf_conntrack_destroy(struct nf_conntrack *nfct) | |
246 | { | |
247 | void (*destroy)(struct nf_conntrack *); | |
248 | ||
249 | rcu_read_lock(); | |
250 | destroy = rcu_dereference(nf_ct_destroy); | |
251 | BUG_ON(destroy == NULL); | |
252 | destroy(nfct); | |
253 | rcu_read_unlock(); | |
254 | } | |
255 | EXPORT_SYMBOL(nf_conntrack_destroy); | |
9cb01766 | 256 | |
5a05fae5 | 257 | struct nfq_ct_hook __rcu *nfq_ct_hook __read_mostly; |
9cb01766 PNA |
258 | EXPORT_SYMBOL_GPL(nfq_ct_hook); |
259 | ||
d584a61a PNA |
260 | struct nfq_ct_nat_hook __rcu *nfq_ct_nat_hook __read_mostly; |
261 | EXPORT_SYMBOL_GPL(nfq_ct_nat_hook); | |
262 | ||
de6e05c4 | 263 | #endif /* CONFIG_NF_CONNTRACK */ |
f6ebe77f | 264 | |
c7232c99 PM |
265 | #ifdef CONFIG_NF_NAT_NEEDED |
266 | void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *); | |
267 | EXPORT_SYMBOL(nf_nat_decode_session_hook); | |
268 | #endif | |
269 | ||
f3c1a44a G |
270 | static int __net_init netfilter_net_init(struct net *net) |
271 | { | |
272 | #ifdef CONFIG_PROC_FS | |
273 | net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter", | |
274 | net->proc_net); | |
12202fa7 PNA |
275 | if (!net->nf.proc_netfilter) { |
276 | if (!net_eq(net, &init_net)) | |
277 | pr_err("cannot create netfilter proc entry"); | |
278 | ||
f3c1a44a G |
279 | return -ENOMEM; |
280 | } | |
281 | #endif | |
282 | return 0; | |
283 | } | |
284 | ||
285 | static void __net_exit netfilter_net_exit(struct net *net) | |
286 | { | |
287 | remove_proc_entry("netfilter", net->proc_net); | |
288 | } | |
289 | ||
290 | static struct pernet_operations netfilter_net_ops = { | |
291 | .init = netfilter_net_init, | |
292 | .exit = netfilter_net_exit, | |
293 | }; | |
294 | ||
6d11cfdb | 295 | int __init netfilter_init(void) |
f6ebe77f | 296 | { |
6d11cfdb PNA |
297 | int i, h, ret; |
298 | ||
7e9c6eeb | 299 | for (i = 0; i < ARRAY_SIZE(nf_hooks); i++) { |
f6ebe77f HW |
300 | for (h = 0; h < NF_MAX_HOOKS; h++) |
301 | INIT_LIST_HEAD(&nf_hooks[i][h]); | |
302 | } | |
303 | ||
6d11cfdb PNA |
304 | ret = register_pernet_subsys(&netfilter_net_ops); |
305 | if (ret < 0) | |
306 | goto err; | |
307 | ||
308 | ret = netfilter_log_init(); | |
309 | if (ret < 0) | |
310 | goto err_pernet; | |
f6ebe77f | 311 | |
6d11cfdb PNA |
312 | return 0; |
313 | err_pernet: | |
314 | unregister_pernet_subsys(&netfilter_net_ops); | |
315 | err: | |
316 | return ret; | |
f6ebe77f | 317 | } |