1
2
3
4
5#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
6#include <linux/module.h>
7#include <linux/gfp.h>
8#include <linux/skbuff.h>
9#include <linux/netfilter_ipv4/ip_tables.h>
10#include <linux/netfilter_ipv6/ip6_tables.h>
11#include <linux/netfilter/x_tables.h>
12#include <linux/netfilter/xt_CT.h>
13#include <net/netfilter/nf_conntrack.h>
14#include <net/netfilter/nf_conntrack_l4proto.h>
15#include <net/netfilter/nf_conntrack_helper.h>
16#include <net/netfilter/nf_conntrack_ecache.h>
17#include <net/netfilter/nf_conntrack_timeout.h>
18#include <net/netfilter/nf_conntrack_zones.h>
19
20static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct)
21{
22
23 if (skb->_nfct != 0)
24 return XT_CONTINUE;
25
26 if (ct) {
27 atomic_inc(&ct->ct_general.use);
28 nf_ct_set(skb, ct, IP_CT_NEW);
29 } else {
30 nf_ct_set(skb, ct, IP_CT_UNTRACKED);
31 }
32
33 return XT_CONTINUE;
34}
35
36static unsigned int xt_ct_target_v0(struct sk_buff *skb,
37 const struct xt_action_param *par)
38{
39 const struct xt_ct_target_info *info = par->targinfo;
40 struct nf_conn *ct = info->ct;
41
42 return xt_ct_target(skb, ct);
43}
44
45static unsigned int xt_ct_target_v1(struct sk_buff *skb,
46 const struct xt_action_param *par)
47{
48 const struct xt_ct_target_info_v1 *info = par->targinfo;
49 struct nf_conn *ct = info->ct;
50
51 return xt_ct_target(skb, ct);
52}
53
54static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
55{
56 if (par->family == NFPROTO_IPV4) {
57 const struct ipt_entry *e = par->entryinfo;
58
59 if (e->ip.invflags & IPT_INV_PROTO)
60 return 0;
61 return e->ip.proto;
62 } else if (par->family == NFPROTO_IPV6) {
63 const struct ip6t_entry *e = par->entryinfo;
64
65 if (e->ipv6.invflags & IP6T_INV_PROTO)
66 return 0;
67 return e->ipv6.proto;
68 } else
69 return 0;
70}
71
72static int
73xt_ct_set_helper(struct nf_conn *ct, const char *helper_name,
74 const struct xt_tgchk_param *par)
75{
76 struct nf_conntrack_helper *helper;
77 struct nf_conn_help *help;
78 u8 proto;
79
80 proto = xt_ct_find_proto(par);
81 if (!proto) {
82 pr_info_ratelimited("You must specify a L4 protocol and not use inversions on it\n");
83 return -ENOENT;
84 }
85
86 helper = nf_conntrack_helper_try_module_get(helper_name, par->family,
87 proto);
88 if (helper == NULL) {
89 pr_info_ratelimited("No such helper \"%s\"\n", helper_name);
90 return -ENOENT;
91 }
92
93 help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
94 if (help == NULL) {
95 nf_conntrack_helper_put(helper);
96 return -ENOMEM;
97 }
98
99 help->helper = helper;
100 return 0;
101}
102
103static int
104xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par,
105 const char *timeout_name)
106{
107#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
108 const struct nf_conntrack_l4proto *l4proto;
109 u8 proto;
110
111 proto = xt_ct_find_proto(par);
112 if (!proto) {
113 pr_info_ratelimited("You must specify a L4 protocol and not "
114 "use inversions on it");
115 return -EINVAL;
116 }
117 l4proto = nf_ct_l4proto_find(proto);
118 return nf_ct_set_timeout(par->net, ct, par->family, l4proto->l4proto,
119 timeout_name);
120
121#else
122 return -EOPNOTSUPP;
123#endif
124}
125
126static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info)
127{
128 switch (info->flags & (XT_CT_ZONE_DIR_ORIG |
129 XT_CT_ZONE_DIR_REPL)) {
130 case XT_CT_ZONE_DIR_ORIG:
131 return NF_CT_ZONE_DIR_ORIG;
132 case XT_CT_ZONE_DIR_REPL:
133 return NF_CT_ZONE_DIR_REPL;
134 default:
135 return NF_CT_DEFAULT_ZONE_DIR;
136 }
137}
138
139static int xt_ct_tg_check(const struct xt_tgchk_param *par,
140 struct xt_ct_target_info_v1 *info)
141{
142 struct nf_conntrack_zone zone;
143 struct nf_conn_help *help;
144 struct nf_conn *ct;
145 int ret = -EOPNOTSUPP;
146
147 if (info->flags & XT_CT_NOTRACK) {
148 ct = NULL;
149 goto out;
150 }
151
152#ifndef CONFIG_NF_CONNTRACK_ZONES
153 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG |
154 XT_CT_ZONE_DIR_REPL |
155 XT_CT_ZONE_MARK))
156 goto err1;
157#endif
158
159 ret = nf_ct_netns_get(par->net, par->family);
160 if (ret < 0)
161 goto err1;
162
163 memset(&zone, 0, sizeof(zone));
164 zone.id = info->zone;
165 zone.dir = xt_ct_flags_to_dir(info);
166 if (info->flags & XT_CT_ZONE_MARK)
167 zone.flags |= NF_CT_FLAG_MARK;
168
169 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL);
170 if (!ct) {
171 ret = -ENOMEM;
172 goto err2;
173 }
174
175 ret = 0;
176 if ((info->ct_events || info->exp_events) &&
177 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
178 GFP_KERNEL)) {
179 ret = -EINVAL;
180 goto err3;
181 }
182
183 if (info->helper[0]) {
184 if (strnlen(info->helper, sizeof(info->helper)) == sizeof(info->helper)) {
185 ret = -ENAMETOOLONG;
186 goto err3;
187 }
188
189 ret = xt_ct_set_helper(ct, info->helper, par);
190 if (ret < 0)
191 goto err3;
192 }
193
194 if (info->timeout[0]) {
195 if (strnlen(info->timeout, sizeof(info->timeout)) == sizeof(info->timeout)) {
196 ret = -ENAMETOOLONG;
197 goto err4;
198 }
199
200 ret = xt_ct_set_timeout(ct, par, info->timeout);
201 if (ret < 0)
202 goto err4;
203 }
204 __set_bit(IPS_CONFIRMED_BIT, &ct->status);
205 nf_conntrack_get(&ct->ct_general);
206out:
207 info->ct = ct;
208 return 0;
209
210err4:
211 help = nfct_help(ct);
212 if (help)
213 nf_conntrack_helper_put(help->helper);
214err3:
215 nf_ct_tmpl_free(ct);
216err2:
217 nf_ct_netns_put(par->net, par->family);
218err1:
219 return ret;
220}
221
222static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
223{
224 struct xt_ct_target_info *info = par->targinfo;
225 struct xt_ct_target_info_v1 info_v1 = {
226 .flags = info->flags,
227 .zone = info->zone,
228 .ct_events = info->ct_events,
229 .exp_events = info->exp_events,
230 };
231 int ret;
232
233 if (info->flags & ~XT_CT_NOTRACK)
234 return -EINVAL;
235
236 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
237
238 ret = xt_ct_tg_check(par, &info_v1);
239 if (ret < 0)
240 return ret;
241
242 info->ct = info_v1.ct;
243
244 return ret;
245}
246
247static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
248{
249 struct xt_ct_target_info_v1 *info = par->targinfo;
250
251 if (info->flags & ~XT_CT_NOTRACK)
252 return -EINVAL;
253
254 return xt_ct_tg_check(par, par->targinfo);
255}
256
257static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par)
258{
259 struct xt_ct_target_info_v1 *info = par->targinfo;
260
261 if (info->flags & ~XT_CT_MASK)
262 return -EINVAL;
263
264 return xt_ct_tg_check(par, par->targinfo);
265}
266
267static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par,
268 struct xt_ct_target_info_v1 *info)
269{
270 struct nf_conn *ct = info->ct;
271 struct nf_conn_help *help;
272
273 if (ct) {
274 help = nfct_help(ct);
275 if (help)
276 nf_conntrack_helper_put(help->helper);
277
278 nf_ct_netns_put(par->net, par->family);
279
280 nf_ct_destroy_timeout(ct);
281 nf_ct_put(info->ct);
282 }
283}
284
285static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
286{
287 struct xt_ct_target_info *info = par->targinfo;
288 struct xt_ct_target_info_v1 info_v1 = {
289 .flags = info->flags,
290 .zone = info->zone,
291 .ct_events = info->ct_events,
292 .exp_events = info->exp_events,
293 .ct = info->ct,
294 };
295 memcpy(info_v1.helper, info->helper, sizeof(info->helper));
296
297 xt_ct_tg_destroy(par, &info_v1);
298}
299
300static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
301{
302 xt_ct_tg_destroy(par, par->targinfo);
303}
304
305static struct xt_target xt_ct_tg_reg[] __read_mostly = {
306 {
307 .name = "CT",
308 .family = NFPROTO_UNSPEC,
309 .targetsize = sizeof(struct xt_ct_target_info),
310 .usersize = offsetof(struct xt_ct_target_info, ct),
311 .checkentry = xt_ct_tg_check_v0,
312 .destroy = xt_ct_tg_destroy_v0,
313 .target = xt_ct_target_v0,
314 .table = "raw",
315 .me = THIS_MODULE,
316 },
317 {
318 .name = "CT",
319 .family = NFPROTO_UNSPEC,
320 .revision = 1,
321 .targetsize = sizeof(struct xt_ct_target_info_v1),
322 .usersize = offsetof(struct xt_ct_target_info, ct),
323 .checkentry = xt_ct_tg_check_v1,
324 .destroy = xt_ct_tg_destroy_v1,
325 .target = xt_ct_target_v1,
326 .table = "raw",
327 .me = THIS_MODULE,
328 },
329 {
330 .name = "CT",
331 .family = NFPROTO_UNSPEC,
332 .revision = 2,
333 .targetsize = sizeof(struct xt_ct_target_info_v1),
334 .usersize = offsetof(struct xt_ct_target_info, ct),
335 .checkentry = xt_ct_tg_check_v2,
336 .destroy = xt_ct_tg_destroy_v1,
337 .target = xt_ct_target_v1,
338 .table = "raw",
339 .me = THIS_MODULE,
340 },
341};
342
343static unsigned int
344notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
345{
346
347 if (skb->_nfct != 0)
348 return XT_CONTINUE;
349
350 nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
351
352 return XT_CONTINUE;
353}
354
355static int notrack_chk(const struct xt_tgchk_param *par)
356{
357 if (!par->net->xt.notrack_deprecated_warning) {
358 pr_info("netfilter: NOTRACK target is deprecated, "
359 "use CT instead or upgrade iptables\n");
360 par->net->xt.notrack_deprecated_warning = true;
361 }
362 return 0;
363}
364
365static struct xt_target notrack_tg_reg __read_mostly = {
366 .name = "NOTRACK",
367 .revision = 0,
368 .family = NFPROTO_UNSPEC,
369 .checkentry = notrack_chk,
370 .target = notrack_tg,
371 .table = "raw",
372 .me = THIS_MODULE,
373};
374
375static int __init xt_ct_tg_init(void)
376{
377 int ret;
378
379 ret = xt_register_target(¬rack_tg_reg);
380 if (ret < 0)
381 return ret;
382
383 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
384 if (ret < 0) {
385 xt_unregister_target(¬rack_tg_reg);
386 return ret;
387 }
388 return 0;
389}
390
391static void __exit xt_ct_tg_exit(void)
392{
393 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
394 xt_unregister_target(¬rack_tg_reg);
395}
396
397module_init(xt_ct_tg_init);
398module_exit(xt_ct_tg_exit);
399
400MODULE_LICENSE("GPL");
401MODULE_DESCRIPTION("Xtables: connection tracking target");
402MODULE_ALIAS("ipt_CT");
403MODULE_ALIAS("ip6t_CT");
404MODULE_ALIAS("ipt_NOTRACK");
405MODULE_ALIAS("ip6t_NOTRACK");
406
