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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, 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 nf_ct_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 nf_ct_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 if (strnlen(info->helper, sizeof(info->helper)) == sizeof(info->helper)) {
249 ret = -ENAMETOOLONG;
250 goto err3;
251 }
252
253 ret = xt_ct_set_helper(ct, info->helper, par);
254 if (ret < 0)
255 goto err3;
256 }
257
258 if (info->timeout[0]) {
259 if (strnlen(info->timeout, sizeof(info->timeout)) == sizeof(info->timeout)) {
260 ret = -ENAMETOOLONG;
261 goto err4;
262 }
263
264 ret = xt_ct_set_timeout(ct, par, info->timeout);
265 if (ret < 0)
266 goto err4;
267 }
268 __set_bit(IPS_CONFIRMED_BIT, &ct->status);
269 nf_conntrack_get(&ct->ct_general);
270out:
271 info->ct = ct;
272 return 0;
273
274err4:
275 help = nfct_help(ct);
276 if (help)
277 nf_conntrack_helper_put(help->helper);
278err3:
279 nf_ct_tmpl_free(ct);
280err2:
281 nf_ct_netns_put(par->net, par->family);
282err1:
283 return ret;
284}
285
286static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
287{
288 struct xt_ct_target_info *info = par->targinfo;
289 struct xt_ct_target_info_v1 info_v1 = {
290 .flags = info->flags,
291 .zone = info->zone,
292 .ct_events = info->ct_events,
293 .exp_events = info->exp_events,
294 };
295 int ret;
296
297 if (info->flags & ~XT_CT_NOTRACK)
298 return -EINVAL;
299
300 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
301
302 ret = xt_ct_tg_check(par, &info_v1);
303 if (ret < 0)
304 return ret;
305
306 info->ct = info_v1.ct;
307
308 return ret;
309}
310
311static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
312{
313 struct xt_ct_target_info_v1 *info = par->targinfo;
314
315 if (info->flags & ~XT_CT_NOTRACK)
316 return -EINVAL;
317
318 return xt_ct_tg_check(par, par->targinfo);
319}
320
321static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par)
322{
323 struct xt_ct_target_info_v1 *info = par->targinfo;
324
325 if (info->flags & ~XT_CT_MASK)
326 return -EINVAL;
327
328 return xt_ct_tg_check(par, par->targinfo);
329}
330
331static void xt_ct_destroy_timeout(struct nf_conn *ct)
332{
333#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
334 struct nf_conn_timeout *timeout_ext;
335 typeof(nf_ct_timeout_put_hook) timeout_put;
336
337 rcu_read_lock();
338 timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
339
340 if (timeout_put) {
341 timeout_ext = nf_ct_timeout_find(ct);
342 if (timeout_ext) {
343 timeout_put(timeout_ext->timeout);
344 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
345 }
346 }
347 rcu_read_unlock();
348#endif
349}
350
351static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
352 struct xt_ct_target_info_v1 *info)
353{
354 struct nf_conn *ct = info->ct;
355 struct nf_conn_help *help;
356
357 if (ct) {
358 help = nfct_help(ct);
359 if (help)
360 nf_conntrack_helper_put(help->helper);
361
362 nf_ct_netns_put(par->net, par->family);
363
364 xt_ct_destroy_timeout(ct);
365 nf_ct_put(info->ct);
366 }
367}
368
369static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
370{
371 struct xt_ct_target_info *info = par->targinfo;
372 struct xt_ct_target_info_v1 info_v1 = {
373 .flags = info->flags,
374 .zone = info->zone,
375 .ct_events = info->ct_events,
376 .exp_events = info->exp_events,
377 .ct = info->ct,
378 };
379 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
380
381 xt_ct_tg_destroy(par, &info_v1);
382}
383
384static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
385{
386 xt_ct_tg_destroy(par, par->targinfo);
387}
388
389static struct xt_target xt_ct_tg_reg[] __read_mostly = {
390 {
391 .name = "CT",
392 .family = NFPROTO_UNSPEC,
393 .targetsize = sizeof(struct xt_ct_target_info),
394 .usersize = offsetof(struct xt_ct_target_info, ct),
395 .checkentry = xt_ct_tg_check_v0,
396 .destroy = xt_ct_tg_destroy_v0,
397 .target = xt_ct_target_v0,
398 .table = "raw",
399 .me = THIS_MODULE,
400 },
401 {
402 .name = "CT",
403 .family = NFPROTO_UNSPEC,
404 .revision = 1,
405 .targetsize = sizeof(struct xt_ct_target_info_v1),
406 .usersize = offsetof(struct xt_ct_target_info, ct),
407 .checkentry = xt_ct_tg_check_v1,
408 .destroy = xt_ct_tg_destroy_v1,
409 .target = xt_ct_target_v1,
410 .table = "raw",
411 .me = THIS_MODULE,
412 },
413 {
414 .name = "CT",
415 .family = NFPROTO_UNSPEC,
416 .revision = 2,
417 .targetsize = sizeof(struct xt_ct_target_info_v1),
418 .usersize = offsetof(struct xt_ct_target_info, ct),
419 .checkentry = xt_ct_tg_check_v2,
420 .destroy = xt_ct_tg_destroy_v1,
421 .target = xt_ct_target_v1,
422 .table = "raw",
423 .me = THIS_MODULE,
424 },
425};
426
427static unsigned int
428notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
429{
430
431 if (skb->_nfct != 0)
432 return XT_CONTINUE;
433
434 nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
435
436 return XT_CONTINUE;
437}
438
439static int notrack_chk(const struct xt_tgchk_param *par)
440{
441 if (!par->net->xt.notrack_deprecated_warning) {
442 pr_info("netfilter: NOTRACK target is deprecated, "
443 "use CT instead or upgrade iptables\n");
444 par->net->xt.notrack_deprecated_warning = true;
445 }
446 return 0;
447}
448
449static struct xt_target notrack_tg_reg __read_mostly = {
450 .name = "NOTRACK",
451 .revision = 0,
452 .family = NFPROTO_UNSPEC,
453 .checkentry = notrack_chk,
454 .target = notrack_tg,
455 .table = "raw",
456 .me = THIS_MODULE,
457};
458
459static int __init xt_ct_tg_init(void)
460{
461 int ret;
462
463 ret = xt_register_target(¬rack_tg_reg);
464 if (ret < 0)
465 return ret;
466
467 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
468 if (ret < 0) {
469 xt_unregister_target(¬rack_tg_reg);
470 return ret;
471 }
472 return 0;
473}
474
475static void __exit xt_ct_tg_exit(void)
476{
477 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
478 xt_unregister_target(¬rack_tg_reg);
479}
480
481module_init(xt_ct_tg_init);
482module_exit(xt_ct_tg_exit);
483
484MODULE_LICENSE("GPL");
485MODULE_DESCRIPTION("Xtables: connection tracking target");
486MODULE_ALIAS("ipt_CT");
487MODULE_ALIAS("ip6t_CT");
488MODULE_ALIAS("ipt_NOTRACK");
489MODULE_ALIAS("ip6t_NOTRACK");
490
