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8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9#include <linux/module.h>
10#include <linux/gfp.h>
11#include <linux/skbuff.h>
12#include <linux/netfilter_ipv4/ip_tables.h>
13#include <linux/netfilter_ipv6/ip6_tables.h>
14#include <linux/netfilter/x_tables.h>
15#include <linux/netfilter/xt_CT.h>
16#include <net/netfilter/nf_conntrack.h>
17#include <net/netfilter/nf_conntrack_l4proto.h>
18#include <net/netfilter/nf_conntrack_helper.h>
19#include <net/netfilter/nf_conntrack_ecache.h>
20#include <net/netfilter/nf_conntrack_timeout.h>
21#include <net/netfilter/nf_conntrack_zones.h>
22
23static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct)
24{
25
26 if (skb->_nfct != 0)
27 return XT_CONTINUE;
28
29 if (ct) {
30 atomic_inc(&ct->ct_general.use);
31 nf_ct_set(skb, ct, IP_CT_NEW);
32 } else {
33 nf_ct_set(skb, ct, IP_CT_UNTRACKED);
34 }
35
36 return XT_CONTINUE;
37}
38
39static unsigned int xt_ct_target_v0(struct sk_buff *skb,
40 const struct xt_action_param *par)
41{
42 const struct xt_ct_target_info *info = par->targinfo;
43 struct nf_conn *ct = info->ct;
44
45 return xt_ct_target(skb, ct);
46}
47
48static unsigned int xt_ct_target_v1(struct sk_buff *skb,
49 const struct xt_action_param *par)
50{
51 const struct xt_ct_target_info_v1 *info = par->targinfo;
52 struct nf_conn *ct = info->ct;
53
54 return xt_ct_target(skb, ct);
55}
56
57static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
58{
59 if (par->family == NFPROTO_IPV4) {
60 const struct ipt_entry *e = par->entryinfo;
61
62 if (e->ip.invflags & IPT_INV_PROTO)
63 return 0;
64 return e->ip.proto;
65 } else if (par->family == NFPROTO_IPV6) {
66 const struct ip6t_entry *e = par->entryinfo;
67
68 if (e->ipv6.invflags & IP6T_INV_PROTO)
69 return 0;
70 return e->ipv6.proto;
71 } else
72 return 0;
73}
74
75static int
76xt_ct_set_helper(struct nf_conn *ct, const char *helper_name,
77 const struct xt_tgchk_param *par)
78{
79 struct nf_conntrack_helper *helper;
80 struct nf_conn_help *help;
81 u8 proto;
82
83 proto = xt_ct_find_proto(par);
84 if (!proto) {
85 pr_info_ratelimited("You must specify a L4 protocol and not use inversions on it\n");
86 return -ENOENT;
87 }
88
89 helper = nf_conntrack_helper_try_module_get(helper_name, par->family,
90 proto);
91 if (helper == NULL) {
92 pr_info_ratelimited("No such helper \"%s\"\n", helper_name);
93 return -ENOENT;
94 }
95
96 help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL);
97 if (help == NULL) {
98 nf_conntrack_helper_put(helper);
99 return -ENOMEM;
100 }
101
102 help->helper = helper;
103 return 0;
104}
105
106#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
107static void __xt_ct_tg_timeout_put(struct ctnl_timeout *timeout)
108{
109 typeof(nf_ct_timeout_put_hook) timeout_put;
110
111 timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
112 if (timeout_put)
113 timeout_put(timeout);
114}
115#endif
116
117static int
118xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par,
119 const char *timeout_name)
120{
121#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
122 typeof(nf_ct_timeout_find_get_hook) timeout_find_get;
123 const struct nf_conntrack_l4proto *l4proto;
124 struct ctnl_timeout *timeout;
125 struct nf_conn_timeout *timeout_ext;
126 const char *errmsg = NULL;
127 int ret = 0;
128 u8 proto;
129
130 rcu_read_lock();
131 timeout_find_get = rcu_dereference(nf_ct_timeout_find_get_hook);
132 if (timeout_find_get == NULL) {
133 ret = -ENOENT;
134 errmsg = "Timeout policy base is empty";
135 goto out;
136 }
137
138 proto = xt_ct_find_proto(par);
139 if (!proto) {
140 ret = -EINVAL;
141 errmsg = "You must specify a L4 protocol and not use inversions on it";
142 goto out;
143 }
144
145 timeout = timeout_find_get(par->net, timeout_name);
146 if (timeout == NULL) {
147 ret = -ENOENT;
148 pr_info_ratelimited("No such timeout policy \"%s\"\n",
149 timeout_name);
150 goto out;
151 }
152
153 if (timeout->l3num != par->family) {
154 ret = -EINVAL;
155 pr_info_ratelimited("Timeout policy `%s' can only be used by L%d protocol number %d\n",
156 timeout_name, 3, timeout->l3num);
157 goto err_put_timeout;
158 }
159
160
161
162 l4proto = __nf_ct_l4proto_find(par->family, proto);
163 if (timeout->l4proto->l4proto != l4proto->l4proto) {
164 ret = -EINVAL;
165 pr_info_ratelimited("Timeout policy `%s' can only be used by L%d protocol number %d\n",
166 timeout_name, 4, timeout->l4proto->l4proto);
167 goto err_put_timeout;
168 }
169 timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC);
170 if (!timeout_ext) {
171 ret = -ENOMEM;
172 goto err_put_timeout;
173 }
174
175 rcu_read_unlock();
176 return ret;
177
178err_put_timeout:
179 __xt_ct_tg_timeout_put(timeout);
180out:
181 rcu_read_unlock();
182 if (errmsg)
183 pr_info_ratelimited("%s\n", errmsg);
184 return ret;
185#else
186 return -EOPNOTSUPP;
187#endif
188}
189
190static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info)
191{
192 switch (info->flags & (XT_CT_ZONE_DIR_ORIG |
193 XT_CT_ZONE_DIR_REPL)) {
194 case XT_CT_ZONE_DIR_ORIG:
195 return NF_CT_ZONE_DIR_ORIG;
196 case XT_CT_ZONE_DIR_REPL:
197 return NF_CT_ZONE_DIR_REPL;
198 default:
199 return NF_CT_DEFAULT_ZONE_DIR;
200 }
201}
202
203static int xt_ct_tg_check(const struct xt_tgchk_param *par,
204 struct xt_ct_target_info_v1 *info)
205{
206 struct nf_conntrack_zone zone;
207 struct nf_conn_help *help;
208 struct nf_conn *ct;
209 int ret = -EOPNOTSUPP;
210
211 if (info->flags & XT_CT_NOTRACK) {
212 ct = NULL;
213 goto out;
214 }
215
216#ifndef CONFIG_NF_CONNTRACK_ZONES
217 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG |
218 XT_CT_ZONE_DIR_REPL |
219 XT_CT_ZONE_MARK))
220 goto err1;
221#endif
222
223 ret = nf_ct_netns_get(par->net, par->family);
224 if (ret < 0)
225 goto err1;
226
227 memset(&zone, 0, sizeof(zone));
228 zone.id = info->zone;
229 zone.dir = xt_ct_flags_to_dir(info);
230 if (info->flags & XT_CT_ZONE_MARK)
231 zone.flags |= NF_CT_FLAG_MARK;
232
233 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL);
234 if (!ct) {
235 ret = -ENOMEM;
236 goto err2;
237 }
238
239 ret = 0;
240 if ((info->ct_events || info->exp_events) &&
241 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
242 GFP_KERNEL)) {
243 ret = -EINVAL;
244 goto err3;
245 }
246
247 if (info->helper[0]) {
248 ret = xt_ct_set_helper(ct, info->helper, par);
249 if (ret < 0)
250 goto err3;
251 }
252
253 if (info->timeout[0]) {
254 ret = xt_ct_set_timeout(ct, par, info->timeout);
255 if (ret < 0)
256 goto err4;
257 }
258 __set_bit(IPS_CONFIRMED_BIT, &ct->status);
259 nf_conntrack_get(&ct->ct_general);
260out:
261 info->ct = ct;
262 return 0;
263
264err4:
265 help = nfct_help(ct);
266 if (help)
267 nf_conntrack_helper_put(help->helper);
268err3:
269 nf_ct_tmpl_free(ct);
270err2:
271 nf_ct_netns_put(par->net, par->family);
272err1:
273 return ret;
274}
275
276static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
277{
278 struct xt_ct_target_info *info = par->targinfo;
279 struct xt_ct_target_info_v1 info_v1 = {
280 .flags = info->flags,
281 .zone = info->zone,
282 .ct_events = info->ct_events,
283 .exp_events = info->exp_events,
284 };
285 int ret;
286
287 if (info->flags & ~XT_CT_NOTRACK)
288 return -EINVAL;
289
290 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
291
292 ret = xt_ct_tg_check(par, &info_v1);
293 if (ret < 0)
294 return ret;
295
296 info->ct = info_v1.ct;
297
298 return ret;
299}
300
301static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
302{
303 struct xt_ct_target_info_v1 *info = par->targinfo;
304
305 if (info->flags & ~XT_CT_NOTRACK)
306 return -EINVAL;
307
308 return xt_ct_tg_check(par, par->targinfo);
309}
310
311static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par)
312{
313 struct xt_ct_target_info_v1 *info = par->targinfo;
314
315 if (info->flags & ~XT_CT_MASK)
316 return -EINVAL;
317
318 return xt_ct_tg_check(par, par->targinfo);
319}
320
321static void xt_ct_destroy_timeout(struct nf_conn *ct)
322{
323#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
324 struct nf_conn_timeout *timeout_ext;
325 typeof(nf_ct_timeout_put_hook) timeout_put;
326
327 rcu_read_lock();
328 timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
329
330 if (timeout_put) {
331 timeout_ext = nf_ct_timeout_find(ct);
332 if (timeout_ext) {
333 timeout_put(timeout_ext->timeout);
334 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
335 }
336 }
337 rcu_read_unlock();
338#endif
339}
340
341static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
342 struct xt_ct_target_info_v1 *info)
343{
344 struct nf_conn *ct = info->ct;
345 struct nf_conn_help *help;
346
347 if (ct) {
348 help = nfct_help(ct);
349 if (help)
350 nf_conntrack_helper_put(help->helper);
351
352 nf_ct_netns_put(par->net, par->family);
353
354 xt_ct_destroy_timeout(ct);
355 nf_ct_put(info->ct);
356 }
357}
358
359static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
360{
361 struct xt_ct_target_info *info = par->targinfo;
362 struct xt_ct_target_info_v1 info_v1 = {
363 .flags = info->flags,
364 .zone = info->zone,
365 .ct_events = info->ct_events,
366 .exp_events = info->exp_events,
367 .ct = info->ct,
368 };
369 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
370
371 xt_ct_tg_destroy(par, &info_v1);
372}
373
374static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
375{
376 xt_ct_tg_destroy(par, par->targinfo);
377}
378
379static struct xt_target xt_ct_tg_reg[] __read_mostly = {
380 {
381 .name = "CT",
382 .family = NFPROTO_UNSPEC,
383 .targetsize = sizeof(struct xt_ct_target_info),
384 .usersize = offsetof(struct xt_ct_target_info, ct),
385 .checkentry = xt_ct_tg_check_v0,
386 .destroy = xt_ct_tg_destroy_v0,
387 .target = xt_ct_target_v0,
388 .table = "raw",
389 .me = THIS_MODULE,
390 },
391 {
392 .name = "CT",
393 .family = NFPROTO_UNSPEC,
394 .revision = 1,
395 .targetsize = sizeof(struct xt_ct_target_info_v1),
396 .usersize = offsetof(struct xt_ct_target_info, ct),
397 .checkentry = xt_ct_tg_check_v1,
398 .destroy = xt_ct_tg_destroy_v1,
399 .target = xt_ct_target_v1,
400 .table = "raw",
401 .me = THIS_MODULE,
402 },
403 {
404 .name = "CT",
405 .family = NFPROTO_UNSPEC,
406 .revision = 2,
407 .targetsize = sizeof(struct xt_ct_target_info_v1),
408 .usersize = offsetof(struct xt_ct_target_info, ct),
409 .checkentry = xt_ct_tg_check_v2,
410 .destroy = xt_ct_tg_destroy_v1,
411 .target = xt_ct_target_v1,
412 .table = "raw",
413 .me = THIS_MODULE,
414 },
415};
416
417static unsigned int
418notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
419{
420
421 if (skb->_nfct != 0)
422 return XT_CONTINUE;
423
424 nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
425
426 return XT_CONTINUE;
427}
428
429static int notrack_chk(const struct xt_tgchk_param *par)
430{
431 if (!par->net->xt.notrack_deprecated_warning) {
432 pr_info("netfilter: NOTRACK target is deprecated, "
433 "use CT instead or upgrade iptables\n");
434 par->net->xt.notrack_deprecated_warning = true;
435 }
436 return 0;
437}
438
439static struct xt_target notrack_tg_reg __read_mostly = {
440 .name = "NOTRACK",
441 .revision = 0,
442 .family = NFPROTO_UNSPEC,
443 .checkentry = notrack_chk,
444 .target = notrack_tg,
445 .table = "raw",
446 .me = THIS_MODULE,
447};
448
449static int __init xt_ct_tg_init(void)
450{
451 int ret;
452
453 ret = xt_register_target(¬rack_tg_reg);
454 if (ret < 0)
455 return ret;
456
457 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
458 if (ret < 0) {
459 xt_unregister_target(¬rack_tg_reg);
460 return ret;
461 }
462 return 0;
463}
464
465static void __exit xt_ct_tg_exit(void)
466{
467 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
468 xt_unregister_target(¬rack_tg_reg);
469}
470
471module_init(xt_ct_tg_init);
472module_exit(xt_ct_tg_exit);
473
474MODULE_LICENSE("GPL");
475MODULE_DESCRIPTION("Xtables: connection tracking target");
476MODULE_ALIAS("ipt_CT");
477MODULE_ALIAS("ip6t_CT");
478MODULE_ALIAS("ipt_NOTRACK");
479MODULE_ALIAS("ip6t_NOTRACK");
480
