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 const struct xt_table security_table = {
32 .name = "security",
33 .valid_hooks = SECURITY_VALID_HOOKS,
34 .me = THIS_MODULE,
35 .af = NFPROTO_IPV4,
36 .priority = NF_IP_PRI_SECURITY,
37 };
38
39 static unsigned int
iptable_security_hook(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)40 iptable_security_hook(void *priv, struct sk_buff *skb,
41 const struct nf_hook_state *state)
42 {
43 if (state->hook == NF_INET_LOCAL_OUT &&
44 (skb->len < sizeof(struct iphdr) ||
45 ip_hdrlen(skb) < sizeof(struct iphdr)))
46 /* Somebody is playing with raw sockets. */
47 return NF_ACCEPT;
48
49 return ipt_do_table(skb, state, state->net->ipv4.iptable_security);
50 }
51
52 static struct nf_hook_ops *sectbl_ops __read_mostly;
53
iptable_security_net_init(struct net * net)54 static int __net_init iptable_security_net_init(struct net *net)
55 {
56 struct ipt_replace *repl;
57
58 repl = ipt_alloc_initial_table(&security_table);
59 if (repl == NULL)
60 return -ENOMEM;
61 net->ipv4.iptable_security =
62 ipt_register_table(net, &security_table, repl);
63 kfree(repl);
64 return PTR_ERR_OR_ZERO(net->ipv4.iptable_security);
65 }
66
iptable_security_net_exit(struct net * net)67 static void __net_exit iptable_security_net_exit(struct net *net)
68 {
69 ipt_unregister_table(net, net->ipv4.iptable_security);
70 }
71
72 static struct pernet_operations iptable_security_net_ops = {
73 .init = iptable_security_net_init,
74 .exit = iptable_security_net_exit,
75 };
76
iptable_security_init(void)77 static int __init iptable_security_init(void)
78 {
79 int ret;
80
81 ret = register_pernet_subsys(&iptable_security_net_ops);
82 if (ret < 0)
83 return ret;
84
85 sectbl_ops = xt_hook_link(&security_table, iptable_security_hook);
86 if (IS_ERR(sectbl_ops)) {
87 ret = PTR_ERR(sectbl_ops);
88 goto cleanup_table;
89 }
90
91 return ret;
92
93 cleanup_table:
94 unregister_pernet_subsys(&iptable_security_net_ops);
95 return ret;
96 }
97
iptable_security_fini(void)98 static void __exit iptable_security_fini(void)
99 {
100 xt_hook_unlink(&security_table, sectbl_ops);
101 unregister_pernet_subsys(&iptable_security_net_ops);
102 }
103
104 module_init(iptable_security_init);
105 module_exit(iptable_security_fini);
106