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(unsigned int hook,struct sk_buff * skb,const struct net_device * in,const struct net_device * out,int (* okfn)(struct sk_buff *))40 iptable_security_hook(unsigned int hook, struct sk_buff *skb,
41 const struct net_device *in,
42 const struct net_device *out,
43 int (*okfn)(struct sk_buff *))
44 {
45 const struct net *net;
46
47 if (hook == NF_INET_LOCAL_OUT &&
48 (skb->len < sizeof(struct iphdr) ||
49 ip_hdrlen(skb) < sizeof(struct iphdr)))
50 /* Somebody is playing with raw sockets. */
51 return NF_ACCEPT;
52
53 net = dev_net((in != NULL) ? in : out);
54 return ipt_do_table(skb, hook, in, out, net->ipv4.iptable_security);
55 }
56
57 static struct nf_hook_ops *sectbl_ops __read_mostly;
58
iptable_security_net_init(struct net * net)59 static int __net_init iptable_security_net_init(struct net *net)
60 {
61 struct ipt_replace *repl;
62
63 repl = ipt_alloc_initial_table(&security_table);
64 if (repl == NULL)
65 return -ENOMEM;
66 net->ipv4.iptable_security =
67 ipt_register_table(net, &security_table, repl);
68 kfree(repl);
69 if (IS_ERR(net->ipv4.iptable_security))
70 return PTR_ERR(net->ipv4.iptable_security);
71
72 return 0;
73 }
74
iptable_security_net_exit(struct net * net)75 static void __net_exit iptable_security_net_exit(struct net *net)
76 {
77 ipt_unregister_table(net, net->ipv4.iptable_security);
78 }
79
80 static struct pernet_operations iptable_security_net_ops = {
81 .init = iptable_security_net_init,
82 .exit = iptable_security_net_exit,
83 };
84
iptable_security_init(void)85 static int __init iptable_security_init(void)
86 {
87 int ret;
88
89 ret = register_pernet_subsys(&iptable_security_net_ops);
90 if (ret < 0)
91 return ret;
92
93 sectbl_ops = xt_hook_link(&security_table, iptable_security_hook);
94 if (IS_ERR(sectbl_ops)) {
95 ret = PTR_ERR(sectbl_ops);
96 goto cleanup_table;
97 }
98
99 return ret;
100
101 cleanup_table:
102 unregister_pernet_subsys(&iptable_security_net_ops);
103 return ret;
104 }
105
iptable_security_fini(void)106 static void __exit iptable_security_fini(void)
107 {
108 xt_hook_unlink(&security_table, sectbl_ops);
109 unregister_pernet_subsys(&iptable_security_net_ops);
110 }
111
112 module_init(iptable_security_init);
113 module_exit(iptable_security_fini);
114