1 /*
2  * "security" table
3  *
4  * This is for use by Mandatory Access Control (MAC) security models,
5  * which need to be able to manage security policy in separate context
6  * to DAC.
7  *
8  * Based on iptable_mangle.c
9  *
10  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
11  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam <at> netfilter.org>
12  * Copyright (C) 2008 Red Hat, Inc., James Morris <jmorris <at> redhat.com>
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License version 2 as
16  * published by the Free Software Foundation.
17  */
18 #include <linux/module.h>
19 #include <linux/netfilter_ipv4/ip_tables.h>
20 #include <linux/slab.h>
21 #include <net/ip.h>
22 
23 MODULE_LICENSE("GPL");
24 MODULE_AUTHOR("James Morris <jmorris <at> redhat.com>");
25 MODULE_DESCRIPTION("iptables security table, for MAC rules");
26 
27 #define SECURITY_VALID_HOOKS	(1 << NF_INET_LOCAL_IN) | \
28 				(1 << NF_INET_FORWARD) | \
29 				(1 << NF_INET_LOCAL_OUT)
30 
31 static int __net_init iptable_security_table_init(struct net *net);
32 
33 static const struct xt_table security_table = {
34 	.name		= "security",
35 	.valid_hooks	= SECURITY_VALID_HOOKS,
36 	.me		= THIS_MODULE,
37 	.af		= NFPROTO_IPV4,
38 	.priority	= NF_IP_PRI_SECURITY,
39 	.table_init	= iptable_security_table_init,
40 };
41 
42 static unsigned int
43 iptable_security_hook(void *priv, struct sk_buff *skb,
44 		      const struct nf_hook_state *state)
45 {
46 	return ipt_do_table(skb, state, state->net->ipv4.iptable_security);
47 }
48 
49 static struct nf_hook_ops *sectbl_ops __read_mostly;
50 
51 static int __net_init iptable_security_table_init(struct net *net)
52 {
53 	struct ipt_replace *repl;
54 	int ret;
55 
56 	if (net->ipv4.iptable_security)
57 		return 0;
58 
59 	repl = ipt_alloc_initial_table(&security_table);
60 	if (repl == NULL)
61 		return -ENOMEM;
62 	ret = ipt_register_table(net, &security_table, repl, sectbl_ops,
63 				 &net->ipv4.iptable_security);
64 	kfree(repl);
65 	return ret;
66 }
67 
68 static void __net_exit iptable_security_net_exit(struct net *net)
69 {
70 	if (!net->ipv4.iptable_security)
71 		return;
72 
73 	ipt_unregister_table(net, net->ipv4.iptable_security, sectbl_ops);
74 	net->ipv4.iptable_security = NULL;
75 }
76 
77 static struct pernet_operations iptable_security_net_ops = {
78 	.exit = iptable_security_net_exit,
79 };
80 
81 static int __init iptable_security_init(void)
82 {
83 	int ret;
84 
85 	sectbl_ops = xt_hook_ops_alloc(&security_table, iptable_security_hook);
86 	if (IS_ERR(sectbl_ops))
87 		return PTR_ERR(sectbl_ops);
88 
89 	ret = register_pernet_subsys(&iptable_security_net_ops);
90 	if (ret < 0) {
91 		kfree(sectbl_ops);
92 		return ret;
93 	}
94 
95 	ret = iptable_security_table_init(&init_net);
96 	if (ret) {
97 		unregister_pernet_subsys(&iptable_security_net_ops);
98 		kfree(sectbl_ops);
99 	}
100 
101 	return ret;
102 }
103 
104 static void __exit iptable_security_fini(void)
105 {
106 	unregister_pernet_subsys(&iptable_security_net_ops);
107 	kfree(sectbl_ops);
108 }
109 
110 module_init(iptable_security_init);
111 module_exit(iptable_security_fini);
112