1 /*
2 * This module is used to copy security markings from packets
3 * to connections, and restore security markings from connections
4 * back to packets. This would normally be performed in conjunction
5 * with the SECMARK target and state match.
6 *
7 * Based somewhat on CONNMARK:
8 * Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
9 * by Henrik Nordstrom <hno@marasystems.com>
10 *
11 * (C) 2006,2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
16 *
17 */
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 #include <linux/module.h>
20 #include <linux/skbuff.h>
21 #include <linux/netfilter/x_tables.h>
22 #include <linux/netfilter/xt_CONNSECMARK.h>
23 #include <net/netfilter/nf_conntrack.h>
24 #include <net/netfilter/nf_conntrack_ecache.h>
25
26 MODULE_LICENSE("GPL");
27 MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
28 MODULE_DESCRIPTION("Xtables: target for copying between connection and security mark");
29 MODULE_ALIAS("ipt_CONNSECMARK");
30 MODULE_ALIAS("ip6t_CONNSECMARK");
31
32 /*
33 * If the packet has a security mark and the connection does not, copy
34 * the security mark from the packet to the connection.
35 */
secmark_save(const struct sk_buff * skb)36 static void secmark_save(const struct sk_buff *skb)
37 {
38 if (skb->secmark) {
39 struct nf_conn *ct;
40 enum ip_conntrack_info ctinfo;
41
42 ct = nf_ct_get(skb, &ctinfo);
43 if (ct && !ct->secmark) {
44 ct->secmark = skb->secmark;
45 nf_conntrack_event_cache(IPCT_SECMARK, ct);
46 }
47 }
48 }
49
50 /*
51 * If packet has no security mark, and the connection does, restore the
52 * security mark from the connection to the packet.
53 */
secmark_restore(struct sk_buff * skb)54 static void secmark_restore(struct sk_buff *skb)
55 {
56 if (!skb->secmark) {
57 const struct nf_conn *ct;
58 enum ip_conntrack_info ctinfo;
59
60 ct = nf_ct_get(skb, &ctinfo);
61 if (ct && ct->secmark)
62 skb->secmark = ct->secmark;
63 }
64 }
65
66 static unsigned int
connsecmark_tg(struct sk_buff * skb,const struct xt_action_param * par)67 connsecmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
68 {
69 const struct xt_connsecmark_target_info *info = par->targinfo;
70
71 switch (info->mode) {
72 case CONNSECMARK_SAVE:
73 secmark_save(skb);
74 break;
75
76 case CONNSECMARK_RESTORE:
77 secmark_restore(skb);
78 break;
79
80 default:
81 BUG();
82 }
83
84 return XT_CONTINUE;
85 }
86
connsecmark_tg_check(const struct xt_tgchk_param * par)87 static int connsecmark_tg_check(const struct xt_tgchk_param *par)
88 {
89 const struct xt_connsecmark_target_info *info = par->targinfo;
90 int ret;
91
92 if (strcmp(par->table, "mangle") != 0 &&
93 strcmp(par->table, "security") != 0) {
94 pr_info_ratelimited("only valid in \'mangle\' or \'security\' table, not \'%s\'\n",
95 par->table);
96 return -EINVAL;
97 }
98
99 switch (info->mode) {
100 case CONNSECMARK_SAVE:
101 case CONNSECMARK_RESTORE:
102 break;
103
104 default:
105 pr_info_ratelimited("invalid mode: %hu\n", info->mode);
106 return -EINVAL;
107 }
108
109 ret = nf_ct_netns_get(par->net, par->family);
110 if (ret < 0)
111 pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
112 par->family);
113 return ret;
114 }
115
connsecmark_tg_destroy(const struct xt_tgdtor_param * par)116 static void connsecmark_tg_destroy(const struct xt_tgdtor_param *par)
117 {
118 nf_ct_netns_put(par->net, par->family);
119 }
120
121 static struct xt_target connsecmark_tg_reg __read_mostly = {
122 .name = "CONNSECMARK",
123 .revision = 0,
124 .family = NFPROTO_UNSPEC,
125 .checkentry = connsecmark_tg_check,
126 .destroy = connsecmark_tg_destroy,
127 .target = connsecmark_tg,
128 .targetsize = sizeof(struct xt_connsecmark_target_info),
129 .me = THIS_MODULE,
130 };
131
connsecmark_tg_init(void)132 static int __init connsecmark_tg_init(void)
133 {
134 return xt_register_target(&connsecmark_tg_reg);
135 }
136
connsecmark_tg_exit(void)137 static void __exit connsecmark_tg_exit(void)
138 {
139 xt_unregister_target(&connsecmark_tg_reg);
140 }
141
142 module_init(connsecmark_tg_init);
143 module_exit(connsecmark_tg_exit);
144
