aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv4/netfilter/iptable_security.c
blob: d9ad60a57413e84a2dde1c83c3f478ee24bdcdf1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
/*
 * "security" table
 *
 * This is for use by Mandatory Access Control (MAC) security models,
 * which need to be able to manage security policy in separate context
 * to DAC.
 *
 * Based on iptable_mangle.c
 *
 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam <at> netfilter.org>
 * Copyright (C) 2008 Red Hat, Inc., James Morris <jmorris <at> redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/slab.h>
#include <net/ip.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Morris <jmorris <at> redhat.com>");
MODULE_DESCRIPTION("iptables security table, for MAC rules");

#define SECURITY_VALID_HOOKS	(1 << NF_INET_LOCAL_IN) | \
				(1 << NF_INET_FORWARD) | \
				(1 << NF_INET_LOCAL_OUT)

static const struct xt_table security_table = {
	.name		= "security",
	.valid_hooks	= SECURITY_VALID_HOOKS,
	.me		= THIS_MODULE,
	.af		= NFPROTO_IPV4,
	.priority	= NF_IP_PRI_SECURITY,
};

static unsigned int
iptable_security_hook(const struct nf_hook_ops *ops, struct sk_buff *skb,
		      const struct nf_hook_state *state)
{
	const struct net *net;

	if (ops->hooknum == NF_INET_LOCAL_OUT &&
	    (skb->len < sizeof(struct iphdr) ||
	     ip_hdrlen(skb) < sizeof(struct iphdr)))
		/* Somebody is playing with raw sockets. */
		return NF_ACCEPT;

	net = dev_net(state->in ? state->in : state->out);
	return ipt_do_table(skb, ops->hooknum, state->in, state->out,
			    net->ipv4.iptable_security);
}

static struct nf_hook_ops *sectbl_ops __read_mostly;

static int __net_init iptable_security_net_init(struct net *net)
{
	struct ipt_replace *repl;

	repl = ipt_alloc_initial_table(&security_table);
	if (repl == NULL)
		return -ENOMEM;
	net->ipv4.iptable_security =
		ipt_register_table(net, &security_table, repl);
	kfree(repl);
	return PTR_ERR_OR_ZERO(net->ipv4.iptable_security);
}

static void __net_exit iptable_security_net_exit(struct net *net)
{
	ipt_unregister_table(net, net->ipv4.iptable_security);
}

static struct pernet_operations iptable_security_net_ops = {
	.init = iptable_security_net_init,
	.exit = iptable_security_net_exit,
};

static int __init iptable_security_init(void)
{
	int ret;

	ret = register_pernet_subsys(&iptable_security_net_ops);
        if (ret < 0)
		return ret;

	sectbl_ops = xt_hook_link(&security_table, iptable_security_hook);
	if (IS_ERR(sectbl_ops)) {
		ret = PTR_ERR(sectbl_ops);
		goto cleanup_table;
	}

	return ret;

cleanup_table:
	unregister_pernet_subsys(&iptable_security_net_ops);
	return ret;
}

static void __exit iptable_security_fini(void)
{
	xt_hook_unlink(&security_table, sectbl_ops);
	unregister_pernet_subsys(&iptable_security_net_ops);
}

module_init(iptable_security_init);
module_exit(iptable_security_fini);