Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-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 *skb, 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         const struct xt_connsecmark_target_info *info = 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
87 static bool checkentry(const char *tablename, const void *entry,
88                        const struct xt_target *target, void *targinfo,
89                        unsigned int hook_mask)
90 {
91         const struct xt_connsecmark_target_info *info = targinfo;
92
93         if (nf_ct_l3proto_try_module_get(target->family) < 0) {
94                 printk(KERN_WARNING "can't load conntrack support for "
95                                     "proto=%d\n", target->family);
96                 return false;
97         }
98         switch (info->mode) {
99         case CONNSECMARK_SAVE:
100         case CONNSECMARK_RESTORE:
101                 break;
102
103         default:
104                 printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode);
105                 return false;
106         }
107
108         return true;
109 }
110
111 static void
112 destroy(const struct xt_target *target, void *targinfo)
113 {
114         nf_ct_l3proto_module_put(target->family);
115 }
116
117 static struct xt_target xt_connsecmark_target[] __read_mostly = {
118         {
119                 .name           = "CONNSECMARK",
120                 .family         = AF_INET,
121                 .checkentry     = checkentry,
122                 .destroy        = destroy,
123                 .target         = target,
124                 .targetsize     = sizeof(struct xt_connsecmark_target_info),
125                 .table          = "mangle",
126                 .me             = THIS_MODULE,
127         },
128         {
129                 .name           = "CONNSECMARK",
130                 .family         = AF_INET6,
131                 .checkentry     = checkentry,
132                 .destroy        = destroy,
133                 .target         = target,
134                 .targetsize     = sizeof(struct xt_connsecmark_target_info),
135                 .table          = "mangle",
136                 .me             = THIS_MODULE,
137         },
138 };
139
140 static int __init xt_connsecmark_init(void)
141 {
142         return xt_register_targets(xt_connsecmark_target,
143                                    ARRAY_SIZE(xt_connsecmark_target));
144 }
145
146 static void __exit xt_connsecmark_fini(void)
147 {
148         xt_unregister_targets(xt_connsecmark_target,
149                               ARRAY_SIZE(xt_connsecmark_target));
150 }
151
152 module_init(xt_connsecmark_init);
153 module_exit(xt_connsecmark_fini);