tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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
27MODULE_LICENSE("GPL");
28MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
29MODULE_DESCRIPTION("Xtables: target for copying between connection and security mark");
30MODULE_ALIAS("ipt_CONNSECMARK");
31MODULE_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 */
37static 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, skb);
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 */
55static 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
67static unsigned int
68connsecmark_tg(struct sk_buff *skb, const struct net_device *in,
69 const struct net_device *out, unsigned int hooknum,
70 const struct xt_target *target, const void *targinfo)
71{
72 const struct xt_connsecmark_target_info *info = targinfo;
73
74 switch (info->mode) {
75 case CONNSECMARK_SAVE:
76 secmark_save(skb);
77 break;
78
79 case CONNSECMARK_RESTORE:
80 secmark_restore(skb);
81 break;
82
83 default:
84 BUG();
85 }
86
87 return XT_CONTINUE;
88}
89
90static bool
91connsecmark_tg_check(const char *tablename, const void *entry,
92 const struct xt_target *target, void *targinfo,
93 unsigned int hook_mask)
94{
95 const struct xt_connsecmark_target_info *info = targinfo;
96
97 if (strcmp(tablename, "mangle") && strcmp(tablename, "security")) {
98 printk(KERN_INFO PFX "target only valid in the \'mangle\' "
99 "or \'security\' tables, not \'%s\'.\n", tablename);
100 return false;
101 }
102
103 switch (info->mode) {
104 case CONNSECMARK_SAVE:
105 case CONNSECMARK_RESTORE:
106 break;
107
108 default:
109 printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode);
110 return false;
111 }
112
113 if (nf_ct_l3proto_try_module_get(target->family) < 0) {
114 printk(KERN_WARNING "can't load conntrack support for "
115 "proto=%u\n", target->family);
116 return false;
117 }
118 return true;
119}
120
121static void
122connsecmark_tg_destroy(const struct xt_target *target, void *targinfo)
123{
124 nf_ct_l3proto_module_put(target->family);
125}
126
127static struct xt_target connsecmark_tg_reg[] __read_mostly = {
128 {
129 .name = "CONNSECMARK",
130 .family = AF_INET,
131 .checkentry = connsecmark_tg_check,
132 .destroy = connsecmark_tg_destroy,
133 .target = connsecmark_tg,
134 .targetsize = sizeof(struct xt_connsecmark_target_info),
135 .me = THIS_MODULE,
136 },
137 {
138 .name = "CONNSECMARK",
139 .family = AF_INET6,
140 .checkentry = connsecmark_tg_check,
141 .destroy = connsecmark_tg_destroy,
142 .target = connsecmark_tg,
143 .targetsize = sizeof(struct xt_connsecmark_target_info),
144 .me = THIS_MODULE,
145 },
146};
147
148static int __init connsecmark_tg_init(void)
149{
150 return xt_register_targets(connsecmark_tg_reg,
151 ARRAY_SIZE(connsecmark_tg_reg));
152}
153
154static void __exit connsecmark_tg_exit(void)
155{
156 xt_unregister_targets(connsecmark_tg_reg,
157 ARRAY_SIZE(connsecmark_tg_reg));
158}
159
160module_init(connsecmark_tg_init);
161module_exit(connsecmark_tg_exit);