Commit | Line | Data |
---|---|---|
64eb12f9 JE |
1 | /* |
2 | * xt_conntrack - Netfilter module to match connection tracking | |
3 | * information. (Superset of Rusty's minimalistic state match.) | |
1da177e4 | 4 | * |
64eb12f9 JE |
5 | * (C) 2001 Marc Boucher (marc@mbsi.ca). |
6 | * Copyright © CC Computer Consultants GmbH, 2007 - 2008 | |
1da177e4 | 7 | * |
64eb12f9 JE |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
1da177e4 LT |
11 | */ |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/skbuff.h> | |
64eb12f9 | 15 | #include <net/ipv6.h> |
2e4e6a17 HW |
16 | #include <linux/netfilter/x_tables.h> |
17 | #include <linux/netfilter/xt_conntrack.h> | |
587aa641 | 18 | #include <net/netfilter/nf_conntrack.h> |
1da177e4 LT |
19 | |
20 | MODULE_LICENSE("GPL"); | |
21 | MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>"); | |
b4164998 | 22 | MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>"); |
2ae15b64 | 23 | MODULE_DESCRIPTION("Xtables: connection tracking state match"); |
2e4e6a17 | 24 | MODULE_ALIAS("ipt_conntrack"); |
64eb12f9 | 25 | MODULE_ALIAS("ip6t_conntrack"); |
1da177e4 | 26 | |
1d93a9cb | 27 | static bool |
64eb12f9 JE |
28 | conntrack_mt_v0(const struct sk_buff *skb, const struct net_device *in, |
29 | const struct net_device *out, const struct xt_match *match, | |
30 | const void *matchinfo, int offset, unsigned int protoff, | |
31 | bool *hotdrop) | |
9fb9cbb1 | 32 | { |
2e4e6a17 | 33 | const struct xt_conntrack_info *sinfo = matchinfo; |
a47362a2 | 34 | const struct nf_conn *ct; |
9fb9cbb1 YK |
35 | enum ip_conntrack_info ctinfo; |
36 | unsigned int statebit; | |
37 | ||
a47362a2 | 38 | ct = nf_ct_get(skb, &ctinfo); |
9fb9cbb1 | 39 | |
e79ec50b | 40 | #define FWINV(bool, invflg) ((bool) ^ !!(sinfo->invflags & (invflg))) |
9fb9cbb1 YK |
41 | |
42 | if (ct == &nf_conntrack_untracked) | |
2e4e6a17 | 43 | statebit = XT_CONNTRACK_STATE_UNTRACKED; |
9fb9cbb1 | 44 | else if (ct) |
601e68e1 YH |
45 | statebit = XT_CONNTRACK_STATE_BIT(ctinfo); |
46 | else | |
47 | statebit = XT_CONNTRACK_STATE_INVALID; | |
48 | ||
50b9f1d5 | 49 | if (sinfo->flags & XT_CONNTRACK_STATE) { |
9fb9cbb1 | 50 | if (ct) { |
50b9f1d5 | 51 | if (test_bit(IPS_SRC_NAT_BIT, &ct->status)) |
2e4e6a17 | 52 | statebit |= XT_CONNTRACK_STATE_SNAT; |
50b9f1d5 | 53 | if (test_bit(IPS_DST_NAT_BIT, &ct->status)) |
2e4e6a17 | 54 | statebit |= XT_CONNTRACK_STATE_DNAT; |
9fb9cbb1 | 55 | } |
50b9f1d5 PM |
56 | if (FWINV((statebit & sinfo->statemask) == 0, |
57 | XT_CONNTRACK_STATE)) | |
1d93a9cb | 58 | return false; |
9fb9cbb1 YK |
59 | } |
60 | ||
50b9f1d5 PM |
61 | if (ct == NULL) { |
62 | if (sinfo->flags & ~XT_CONNTRACK_STATE) | |
1d93a9cb JE |
63 | return false; |
64 | return true; | |
9fb9cbb1 YK |
65 | } |
66 | ||
50b9f1d5 | 67 | if (sinfo->flags & XT_CONNTRACK_PROTO && |
5e8fbe2a | 68 | FWINV(nf_ct_protonum(ct) != |
601e68e1 | 69 | sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum, |
50b9f1d5 | 70 | XT_CONNTRACK_PROTO)) |
1d93a9cb | 71 | return false; |
50b9f1d5 PM |
72 | |
73 | if (sinfo->flags & XT_CONNTRACK_ORIGSRC && | |
74 | FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip & | |
601e68e1 | 75 | sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) != |
50b9f1d5 PM |
76 | sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip, |
77 | XT_CONNTRACK_ORIGSRC)) | |
1d93a9cb | 78 | return false; |
9fb9cbb1 | 79 | |
50b9f1d5 PM |
80 | if (sinfo->flags & XT_CONNTRACK_ORIGDST && |
81 | FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip & | |
601e68e1 | 82 | sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) != |
50b9f1d5 PM |
83 | sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip, |
84 | XT_CONNTRACK_ORIGDST)) | |
1d93a9cb | 85 | return false; |
9fb9cbb1 | 86 | |
50b9f1d5 PM |
87 | if (sinfo->flags & XT_CONNTRACK_REPLSRC && |
88 | FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip & | |
601e68e1 | 89 | sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) != |
50b9f1d5 PM |
90 | sinfo->tuple[IP_CT_DIR_REPLY].src.ip, |
91 | XT_CONNTRACK_REPLSRC)) | |
1d93a9cb | 92 | return false; |
9fb9cbb1 | 93 | |
50b9f1d5 PM |
94 | if (sinfo->flags & XT_CONNTRACK_REPLDST && |
95 | FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip & | |
601e68e1 | 96 | sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) != |
50b9f1d5 PM |
97 | sinfo->tuple[IP_CT_DIR_REPLY].dst.ip, |
98 | XT_CONNTRACK_REPLDST)) | |
1d93a9cb | 99 | return false; |
9fb9cbb1 | 100 | |
50b9f1d5 PM |
101 | if (sinfo->flags & XT_CONNTRACK_STATUS && |
102 | FWINV((ct->status & sinfo->statusmask) == 0, | |
601e68e1 | 103 | XT_CONNTRACK_STATUS)) |
1d93a9cb | 104 | return false; |
9fb9cbb1 | 105 | |
50b9f1d5 PM |
106 | if(sinfo->flags & XT_CONNTRACK_EXPIRES) { |
107 | unsigned long expires = timer_pending(&ct->timeout) ? | |
108 | (ct->timeout.expires - jiffies)/HZ : 0; | |
9fb9cbb1 | 109 | |
50b9f1d5 PM |
110 | if (FWINV(!(expires >= sinfo->expires_min && |
111 | expires <= sinfo->expires_max), | |
112 | XT_CONNTRACK_EXPIRES)) | |
1d93a9cb | 113 | return false; |
9fb9cbb1 | 114 | } |
1d93a9cb | 115 | return true; |
e79ec50b | 116 | #undef FWINV |
9fb9cbb1 YK |
117 | } |
118 | ||
64eb12f9 JE |
119 | static bool |
120 | conntrack_addrcmp(const union nf_inet_addr *kaddr, | |
121 | const union nf_inet_addr *uaddr, | |
122 | const union nf_inet_addr *umask, unsigned int l3proto) | |
123 | { | |
124 | if (l3proto == AF_INET) | |
6556874d | 125 | return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0; |
64eb12f9 JE |
126 | else if (l3proto == AF_INET6) |
127 | return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6, | |
128 | &uaddr->in6) == 0; | |
129 | else | |
130 | return false; | |
131 | } | |
132 | ||
133 | static inline bool | |
134 | conntrack_mt_origsrc(const struct nf_conn *ct, | |
135 | const struct xt_conntrack_mtinfo1 *info, | |
136 | unsigned int family) | |
137 | { | |
138 | return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3, | |
139 | &info->origsrc_addr, &info->origsrc_mask, family); | |
140 | } | |
141 | ||
142 | static inline bool | |
143 | conntrack_mt_origdst(const struct nf_conn *ct, | |
144 | const struct xt_conntrack_mtinfo1 *info, | |
145 | unsigned int family) | |
146 | { | |
147 | return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3, | |
148 | &info->origdst_addr, &info->origdst_mask, family); | |
149 | } | |
150 | ||
151 | static inline bool | |
152 | conntrack_mt_replsrc(const struct nf_conn *ct, | |
153 | const struct xt_conntrack_mtinfo1 *info, | |
154 | unsigned int family) | |
155 | { | |
156 | return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3, | |
157 | &info->replsrc_addr, &info->replsrc_mask, family); | |
158 | } | |
159 | ||
160 | static inline bool | |
161 | conntrack_mt_repldst(const struct nf_conn *ct, | |
162 | const struct xt_conntrack_mtinfo1 *info, | |
163 | unsigned int family) | |
164 | { | |
165 | return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3, | |
166 | &info->repldst_addr, &info->repldst_mask, family); | |
167 | } | |
168 | ||
b4164998 JE |
169 | static inline bool |
170 | ct_proto_port_check(const struct xt_conntrack_mtinfo1 *info, | |
171 | const struct nf_conn *ct) | |
172 | { | |
173 | const struct nf_conntrack_tuple *tuple; | |
174 | ||
175 | tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | |
176 | if ((info->match_flags & XT_CONNTRACK_PROTO) && | |
5e8fbe2a | 177 | (nf_ct_protonum(ct) == info->l4proto) ^ |
b4164998 JE |
178 | !(info->invert_flags & XT_CONNTRACK_PROTO)) |
179 | return false; | |
180 | ||
181 | /* Shortcut to match all recognized protocols by using ->src.all. */ | |
182 | if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) && | |
183 | (tuple->src.u.all == info->origsrc_port) ^ | |
184 | !(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT)) | |
185 | return false; | |
186 | ||
187 | if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) && | |
188 | (tuple->dst.u.all == info->origdst_port) ^ | |
189 | !(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT)) | |
190 | return false; | |
191 | ||
192 | tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; | |
193 | ||
194 | if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) && | |
195 | (tuple->src.u.all == info->replsrc_port) ^ | |
196 | !(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT)) | |
197 | return false; | |
198 | ||
199 | if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) && | |
200 | (tuple->dst.u.all == info->repldst_port) ^ | |
201 | !(info->invert_flags & XT_CONNTRACK_REPLDST_PORT)) | |
202 | return false; | |
203 | ||
204 | return true; | |
205 | } | |
206 | ||
64eb12f9 JE |
207 | static bool |
208 | conntrack_mt(const struct sk_buff *skb, const struct net_device *in, | |
209 | const struct net_device *out, const struct xt_match *match, | |
210 | const void *matchinfo, int offset, unsigned int protoff, | |
211 | bool *hotdrop) | |
212 | { | |
213 | const struct xt_conntrack_mtinfo1 *info = matchinfo; | |
214 | enum ip_conntrack_info ctinfo; | |
215 | const struct nf_conn *ct; | |
216 | unsigned int statebit; | |
217 | ||
218 | ct = nf_ct_get(skb, &ctinfo); | |
219 | ||
220 | if (ct == &nf_conntrack_untracked) | |
221 | statebit = XT_CONNTRACK_STATE_UNTRACKED; | |
222 | else if (ct != NULL) | |
223 | statebit = XT_CONNTRACK_STATE_BIT(ctinfo); | |
224 | else | |
225 | statebit = XT_CONNTRACK_STATE_INVALID; | |
226 | ||
227 | if (info->match_flags & XT_CONNTRACK_STATE) { | |
228 | if (ct != NULL) { | |
229 | if (test_bit(IPS_SRC_NAT_BIT, &ct->status)) | |
230 | statebit |= XT_CONNTRACK_STATE_SNAT; | |
231 | if (test_bit(IPS_DST_NAT_BIT, &ct->status)) | |
232 | statebit |= XT_CONNTRACK_STATE_DNAT; | |
233 | } | |
d61f89e9 | 234 | if (!!(info->state_mask & statebit) ^ |
64eb12f9 JE |
235 | !(info->invert_flags & XT_CONNTRACK_STATE)) |
236 | return false; | |
237 | } | |
238 | ||
239 | if (ct == NULL) | |
240 | return info->match_flags & XT_CONNTRACK_STATE; | |
b4164998 JE |
241 | if ((info->match_flags & XT_CONNTRACK_DIRECTION) && |
242 | (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^ | |
243 | !!(info->invert_flags & XT_CONNTRACK_DIRECTION)) | |
64eb12f9 JE |
244 | return false; |
245 | ||
246 | if (info->match_flags & XT_CONNTRACK_ORIGSRC) | |
247 | if (conntrack_mt_origsrc(ct, info, match->family) ^ | |
248 | !(info->invert_flags & XT_CONNTRACK_ORIGSRC)) | |
249 | return false; | |
250 | ||
251 | if (info->match_flags & XT_CONNTRACK_ORIGDST) | |
252 | if (conntrack_mt_origdst(ct, info, match->family) ^ | |
253 | !(info->invert_flags & XT_CONNTRACK_ORIGDST)) | |
254 | return false; | |
255 | ||
256 | if (info->match_flags & XT_CONNTRACK_REPLSRC) | |
257 | if (conntrack_mt_replsrc(ct, info, match->family) ^ | |
258 | !(info->invert_flags & XT_CONNTRACK_REPLSRC)) | |
259 | return false; | |
260 | ||
261 | if (info->match_flags & XT_CONNTRACK_REPLDST) | |
262 | if (conntrack_mt_repldst(ct, info, match->family) ^ | |
263 | !(info->invert_flags & XT_CONNTRACK_REPLDST)) | |
264 | return false; | |
265 | ||
b4164998 JE |
266 | if (!ct_proto_port_check(info, ct)) |
267 | return false; | |
268 | ||
64eb12f9 JE |
269 | if ((info->match_flags & XT_CONNTRACK_STATUS) && |
270 | (!!(info->status_mask & ct->status) ^ | |
271 | !(info->invert_flags & XT_CONNTRACK_STATUS))) | |
272 | return false; | |
273 | ||
274 | if (info->match_flags & XT_CONNTRACK_EXPIRES) { | |
275 | unsigned long expires = 0; | |
276 | ||
277 | if (timer_pending(&ct->timeout)) | |
278 | expires = (ct->timeout.expires - jiffies) / HZ; | |
279 | if ((expires >= info->expires_min && | |
280 | expires <= info->expires_max) ^ | |
281 | !(info->invert_flags & XT_CONNTRACK_EXPIRES)) | |
282 | return false; | |
283 | } | |
284 | return true; | |
285 | } | |
286 | ||
ccb79bdc | 287 | static bool |
d3c5ee6d JE |
288 | conntrack_mt_check(const char *tablename, const void *ip, |
289 | const struct xt_match *match, void *matchinfo, | |
290 | unsigned int hook_mask) | |
b9f78f9f | 291 | { |
b9f78f9f | 292 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { |
fe0b9294 | 293 | printk(KERN_WARNING "can't load conntrack support for " |
df54aae0 | 294 | "proto=%u\n", match->family); |
ccb79bdc | 295 | return false; |
b9f78f9f | 296 | } |
ccb79bdc | 297 | return true; |
b9f78f9f PNA |
298 | } |
299 | ||
d3c5ee6d JE |
300 | static void |
301 | conntrack_mt_destroy(const struct xt_match *match, void *matchinfo) | |
b9f78f9f | 302 | { |
b9f78f9f | 303 | nf_ct_l3proto_module_put(match->family); |
b9f78f9f PNA |
304 | } |
305 | ||
da0dd231 PM |
306 | #ifdef CONFIG_COMPAT |
307 | struct compat_xt_conntrack_info | |
308 | { | |
309 | compat_uint_t statemask; | |
310 | compat_uint_t statusmask; | |
311 | struct ip_conntrack_old_tuple tuple[IP_CT_DIR_MAX]; | |
312 | struct in_addr sipmsk[IP_CT_DIR_MAX]; | |
313 | struct in_addr dipmsk[IP_CT_DIR_MAX]; | |
314 | compat_ulong_t expires_min; | |
315 | compat_ulong_t expires_max; | |
316 | u_int8_t flags; | |
317 | u_int8_t invflags; | |
318 | }; | |
319 | ||
64eb12f9 | 320 | static void conntrack_mt_compat_from_user_v0(void *dst, void *src) |
da0dd231 | 321 | { |
a47362a2 | 322 | const struct compat_xt_conntrack_info *cm = src; |
da0dd231 PM |
323 | struct xt_conntrack_info m = { |
324 | .statemask = cm->statemask, | |
325 | .statusmask = cm->statusmask, | |
326 | .expires_min = cm->expires_min, | |
327 | .expires_max = cm->expires_max, | |
328 | .flags = cm->flags, | |
329 | .invflags = cm->invflags, | |
330 | }; | |
331 | memcpy(m.tuple, cm->tuple, sizeof(m.tuple)); | |
332 | memcpy(m.sipmsk, cm->sipmsk, sizeof(m.sipmsk)); | |
333 | memcpy(m.dipmsk, cm->dipmsk, sizeof(m.dipmsk)); | |
334 | memcpy(dst, &m, sizeof(m)); | |
335 | } | |
336 | ||
64eb12f9 | 337 | static int conntrack_mt_compat_to_user_v0(void __user *dst, void *src) |
da0dd231 | 338 | { |
a47362a2 | 339 | const struct xt_conntrack_info *m = src; |
da0dd231 PM |
340 | struct compat_xt_conntrack_info cm = { |
341 | .statemask = m->statemask, | |
342 | .statusmask = m->statusmask, | |
343 | .expires_min = m->expires_min, | |
344 | .expires_max = m->expires_max, | |
345 | .flags = m->flags, | |
346 | .invflags = m->invflags, | |
347 | }; | |
348 | memcpy(cm.tuple, m->tuple, sizeof(cm.tuple)); | |
349 | memcpy(cm.sipmsk, m->sipmsk, sizeof(cm.sipmsk)); | |
350 | memcpy(cm.dipmsk, m->dipmsk, sizeof(cm.dipmsk)); | |
351 | return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0; | |
352 | } | |
353 | #endif | |
354 | ||
64eb12f9 JE |
355 | static struct xt_match conntrack_mt_reg[] __read_mostly = { |
356 | { | |
357 | .name = "conntrack", | |
358 | .revision = 0, | |
359 | .family = AF_INET, | |
360 | .match = conntrack_mt_v0, | |
361 | .checkentry = conntrack_mt_check, | |
362 | .destroy = conntrack_mt_destroy, | |
363 | .matchsize = sizeof(struct xt_conntrack_info), | |
364 | .me = THIS_MODULE, | |
da0dd231 | 365 | #ifdef CONFIG_COMPAT |
64eb12f9 JE |
366 | .compatsize = sizeof(struct compat_xt_conntrack_info), |
367 | .compat_from_user = conntrack_mt_compat_from_user_v0, | |
368 | .compat_to_user = conntrack_mt_compat_to_user_v0, | |
da0dd231 | 369 | #endif |
64eb12f9 JE |
370 | }, |
371 | { | |
372 | .name = "conntrack", | |
373 | .revision = 1, | |
374 | .family = AF_INET, | |
375 | .matchsize = sizeof(struct xt_conntrack_mtinfo1), | |
376 | .match = conntrack_mt, | |
377 | .checkentry = conntrack_mt_check, | |
378 | .destroy = conntrack_mt_destroy, | |
379 | .me = THIS_MODULE, | |
380 | }, | |
381 | { | |
382 | .name = "conntrack", | |
383 | .revision = 1, | |
384 | .family = AF_INET6, | |
385 | .matchsize = sizeof(struct xt_conntrack_mtinfo1), | |
386 | .match = conntrack_mt, | |
387 | .checkentry = conntrack_mt_check, | |
388 | .destroy = conntrack_mt_destroy, | |
389 | .me = THIS_MODULE, | |
390 | }, | |
1da177e4 LT |
391 | }; |
392 | ||
d3c5ee6d | 393 | static int __init conntrack_mt_init(void) |
1da177e4 | 394 | { |
64eb12f9 JE |
395 | return xt_register_matches(conntrack_mt_reg, |
396 | ARRAY_SIZE(conntrack_mt_reg)); | |
1da177e4 LT |
397 | } |
398 | ||
d3c5ee6d | 399 | static void __exit conntrack_mt_exit(void) |
1da177e4 | 400 | { |
64eb12f9 | 401 | xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg)); |
1da177e4 LT |
402 | } |
403 | ||
d3c5ee6d JE |
404 | module_init(conntrack_mt_init); |
405 | module_exit(conntrack_mt_exit); |