Merge master.kernel.org:/pub/scm/linux/kernel/git/bart/ide-2.6
[linux-2.6] / net / netfilter / xt_CONNSECMARK.c
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 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
24 #define PFX "CONNSECMARK: "
25
26 MODULE_LICENSE("GPL");
27 MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
28 MODULE_DESCRIPTION("ip[6]tables CONNSECMARK module");
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  */
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         }
46 }
47
48 /*
49  * If packet has no security mark, and the connection does, restore the
50  * security mark from the connection to the packet.
51  */
52 static void secmark_restore(struct sk_buff *skb)
53 {
54         if (!skb->secmark) {
55                 struct nf_conn *ct;
56                 enum ip_conntrack_info ctinfo;
57
58                 ct = nf_ct_get(skb, &ctinfo);
59                 if (ct && ct->secmark)
60                         skb->secmark = ct->secmark;
61         }
62 }
63
64 static unsigned int target(struct sk_buff **pskb, const struct net_device *in,
65                            const struct net_device *out, unsigned int hooknum,
66                            const struct xt_target *target,
67                            const void *targinfo)
68 {
69         struct sk_buff *skb = *pskb;
70         const struct xt_connsecmark_target_info *info = 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
88 static bool checkentry(const char *tablename, const void *entry,
89                        const struct xt_target *target, void *targinfo,
90                        unsigned int hook_mask)
91 {
92         const struct xt_connsecmark_target_info *info = targinfo;
93
94         if (nf_ct_l3proto_try_module_get(target->family) < 0) {
95                 printk(KERN_WARNING "can't load conntrack support for "
96                                     "proto=%d\n", target->family);
97                 return false;
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         return true;
110 }
111
112 static void
113 destroy(const struct xt_target *target, void *targinfo)
114 {
115         nf_ct_l3proto_module_put(target->family);
116 }
117
118 static struct xt_target xt_connsecmark_target[] __read_mostly = {
119         {
120                 .name           = "CONNSECMARK",
121                 .family         = AF_INET,
122                 .checkentry     = checkentry,
123                 .destroy        = destroy,
124                 .target         = target,
125                 .targetsize     = sizeof(struct xt_connsecmark_target_info),
126                 .table          = "mangle",
127                 .me             = THIS_MODULE,
128         },
129         {
130                 .name           = "CONNSECMARK",
131                 .family         = AF_INET6,
132                 .checkentry     = checkentry,
133                 .destroy        = destroy,
134                 .target         = target,
135                 .targetsize     = sizeof(struct xt_connsecmark_target_info),
136                 .table          = "mangle",
137                 .me             = THIS_MODULE,
138         },
139 };
140
141 static int __init xt_connsecmark_init(void)
142 {
143         return xt_register_targets(xt_connsecmark_target,
144                                    ARRAY_SIZE(xt_connsecmark_target));
145 }
146
147 static void __exit xt_connsecmark_fini(void)
148 {
149         xt_unregister_targets(xt_connsecmark_target,
150                               ARRAY_SIZE(xt_connsecmark_target));
151 }
152
153 module_init(xt_connsecmark_init);
154 module_exit(xt_connsecmark_fini);