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(const struct nf_hook_ops * ops,struct sk_buff * skb,const struct nf_hook_state * state)40 iptable_security_hook(const struct nf_hook_ops *ops, struct sk_buff *skb,
41 const struct nf_hook_state *state)
42 {
43 const struct net *net;
44
45 if (ops->hooknum == NF_INET_LOCAL_OUT &&
46 (skb->len < sizeof(struct iphdr) ||
47 ip_hdrlen(skb) < sizeof(struct iphdr)))
48 /* Somebody is playing with raw sockets. */
49 return NF_ACCEPT;
50
51 net = dev_net(state->in ? state->in : state->out);
52 return ipt_do_table(skb, ops->hooknum, state,
53 net->ipv4.iptable_security);
54 }
55
56 static struct nf_hook_ops *sectbl_ops __read_mostly;
57
iptable_security_net_init(struct net * net)58 static int __net_init iptable_security_net_init(struct net *net)
59 {
60 struct ipt_replace *repl;
61
62 repl = ipt_alloc_initial_table(&security_table);
63 if (repl == NULL)
64 return -ENOMEM;
65 net->ipv4.iptable_security =
66 ipt_register_table(net, &security_table, repl);
67 kfree(repl);
68 return PTR_ERR_OR_ZERO(net->ipv4.iptable_security);
69 }
70
iptable_security_net_exit(struct net * net)71 static void __net_exit iptable_security_net_exit(struct net *net)
72 {
73 ipt_unregister_table(net, net->ipv4.iptable_security);
74 }
75
76 static struct pernet_operations iptable_security_net_ops = {
77 .init = iptable_security_net_init,
78 .exit = iptable_security_net_exit,
79 };
80
iptable_security_init(void)81 static int __init iptable_security_init(void)
82 {
83 int ret;
84
85 ret = register_pernet_subsys(&iptable_security_net_ops);
86 if (ret < 0)
87 return ret;
88
89 sectbl_ops = xt_hook_link(&security_table, iptable_security_hook);
90 if (IS_ERR(sectbl_ops)) {
91 ret = PTR_ERR(sectbl_ops);
92 goto cleanup_table;
93 }
94
95 return ret;
96
97 cleanup_table:
98 unregister_pernet_subsys(&iptable_security_net_ops);
99 return ret;
100 }
101
iptable_security_fini(void)102 static void __exit iptable_security_fini(void)
103 {
104 xt_hook_unlink(&security_table, sectbl_ops);
105 unregister_pernet_subsys(&iptable_security_net_ops);
106 }
107
108 module_init(iptable_security_init);
109 module_exit(iptable_security_fini);
110