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 #include <linux/module.h>
19 #include <linux/skbuff.h>
20 #include <linux/netfilter/x_tables.h>
21 #include <linux/netfilter/xt_CONNSECMARK.h>
22 #include <net/netfilter/nf_conntrack.h>
23 #include <net/netfilter/nf_conntrack_ecache.h>
24
25 #define PFX "CONNSECMARK: "
26
27 MODULE_LICENSE("GPL");
28 MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
29 MODULE_DESCRIPTION("Xtables: target for copying between connection and security mark");
30 MODULE_ALIAS("ipt_CONNSECMARK");
31 MODULE_ALIAS("ip6t_CONNSECMARK");
32
33 /*
34 * If the packet has a security mark and the connection does not, copy
35 * the security mark from the packet to the connection.
36 */
secmark_save(const struct sk_buff * skb)37 static void secmark_save(const struct sk_buff *skb)
38 {
39 if (skb->secmark) {
40 struct nf_conn *ct;
41 enum ip_conntrack_info ctinfo;
42
43 ct = nf_ct_get(skb, &ctinfo);
44 if (ct && !ct->secmark) {
45 ct->secmark = skb->secmark;
46 nf_conntrack_event_cache(IPCT_SECMARK, ct);
47 }
48 }
49 }
50
51 /*
52 * If packet has no security mark, and the connection does, restore the
53 * security mark from the connection to the packet.
54 */
secmark_restore(struct sk_buff * skb)55 static void secmark_restore(struct sk_buff *skb)
56 {
57 if (!skb->secmark) {
58 const struct nf_conn *ct;
59 enum ip_conntrack_info ctinfo;
60
61 ct = nf_ct_get(skb, &ctinfo);
62 if (ct && ct->secmark)
63 skb->secmark = ct->secmark;
64 }
65 }
66
67 static unsigned int
connsecmark_tg(struct sk_buff * skb,const struct xt_target_param * par)68 connsecmark_tg(struct sk_buff *skb, const struct xt_target_param *par)
69 {
70 const struct xt_connsecmark_target_info *info = par->targinfo;
71
72 switch (info->mode) {
73 case CONNSECMARK_SAVE:
74 secmark_save(skb);
75 break;
76
77 case CONNSECMARK_RESTORE:
78 secmark_restore(skb);
79 break;
80
81 default:
82 BUG();
83 }
84
85 return XT_CONTINUE;
86 }
87
connsecmark_tg_check(const struct xt_tgchk_param * par)88 static bool connsecmark_tg_check(const struct xt_tgchk_param *par)
89 {
90 const struct xt_connsecmark_target_info *info = par->targinfo;
91
92 if (strcmp(par->table, "mangle") != 0 &&
93 strcmp(par->table, "security") != 0) {
94 printk(KERN_INFO PFX "target only valid in the \'mangle\' "
95 "or \'security\' tables, not \'%s\'.\n", par->table);
96 return false;
97 }
98
99 switch (info->mode) {
100 case CONNSECMARK_SAVE:
101 case CONNSECMARK_RESTORE:
102 break;
103
104 default:
105 printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode);
106 return false;
107 }
108
109 if (nf_ct_l3proto_try_module_get(par->family) < 0) {
110 printk(KERN_WARNING "can't load conntrack support for "
111 "proto=%u\n", par->family);
112 return false;
113 }
114 return true;
115 }
116
connsecmark_tg_destroy(const struct xt_tgdtor_param * par)117 static void connsecmark_tg_destroy(const struct xt_tgdtor_param *par)
118 {
119 nf_ct_l3proto_module_put(par->family);
120 }
121
122 static struct xt_target connsecmark_tg_reg __read_mostly = {
123 .name = "CONNSECMARK",
124 .revision = 0,
125 .family = NFPROTO_UNSPEC,
126 .checkentry = connsecmark_tg_check,
127 .destroy = connsecmark_tg_destroy,
128 .target = connsecmark_tg,
129 .targetsize = sizeof(struct xt_connsecmark_target_info),
130 .me = THIS_MODULE,
131 };
132
connsecmark_tg_init(void)133 static int __init connsecmark_tg_init(void)
134 {
135 return xt_register_target(&connsecmark_tg_reg);
136 }
137
connsecmark_tg_exit(void)138 static void __exit connsecmark_tg_exit(void)
139 {
140 xt_unregister_target(&connsecmark_tg_reg);
141 }
142
143 module_init(connsecmark_tg_init);
144 module_exit(connsecmark_tg_exit);
145