aboutsummaryrefslogtreecommitdiffstats
path: root/net/bridge/netfilter/nf_tables_bridge.c
blob: 19473a9371b8a65ed6b1e8727a5c2b321862886b (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
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
/*
 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
 * Copyright (c) 2013 Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * 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.
 *
 * Development of this code funded by Astaro AG (http://www.astaro.com/)
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/netfilter_bridge.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_bridge.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <net/netfilter/nf_tables_ipv4.h>
#include <net/netfilter/nf_tables_ipv6.h>

int nft_bridge_iphdr_validate(struct sk_buff *skb)
{
	struct iphdr *iph;
	u32 len;

	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
		return 0;

	iph = ip_hdr(skb);
	if (iph->ihl < 5 || iph->version != 4)
		return 0;

	len = ntohs(iph->tot_len);
	if (skb->len < len)
		return 0;
	else if (len < (iph->ihl*4))
		return 0;

	if (!pskb_may_pull(skb, iph->ihl*4))
		return 0;

	return 1;
}
EXPORT_SYMBOL_GPL(nft_bridge_iphdr_validate);

int nft_bridge_ip6hdr_validate(struct sk_buff *skb)
{
	struct ipv6hdr *hdr;
	u32 pkt_len;

	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
		return 0;

	hdr = ipv6_hdr(skb);
	if (hdr->version != 6)
		return 0;

	pkt_len = ntohs(hdr->payload_len);
	if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
		return 0;

	return 1;
}
EXPORT_SYMBOL_GPL(nft_bridge_ip6hdr_validate);

static inline void nft_bridge_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
					       const struct nf_hook_ops *ops,
					       struct sk_buff *skb,
					       const struct net_device *in,
					       const struct net_device *out)
{
	if (nft_bridge_iphdr_validate(skb))
		nft_set_pktinfo_ipv4(pkt, ops, skb, in, out);
	else
		nft_set_pktinfo(pkt, ops, skb, in, out);
}

static inline void nft_bridge_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
					      const struct nf_hook_ops *ops,
					      struct sk_buff *skb,
					      const struct net_device *in,
					      const struct net_device *out)
{
#if IS_ENABLED(CONFIG_IPV6)
	if (nft_bridge_ip6hdr_validate(skb) &&
	    nft_set_pktinfo_ipv6(pkt, ops, skb, in, out) == 0)
		return;
#endif
	nft_set_pktinfo(pkt, ops, skb, in, out);
}

static unsigned int
nft_do_chain_bridge(const struct nf_hook_ops *ops,
		    struct sk_buff *skb,
		    const struct net_device *in,
		    const struct net_device *out,
		    int (*okfn)(struct sk_buff *))
{
	struct nft_pktinfo pkt;

	switch (eth_hdr(skb)->h_proto) {
	case htons(ETH_P_IP):
		nft_bridge_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
		break;
	case htons(ETH_P_IPV6):
		nft_bridge_set_pktinfo_ipv6(&pkt, ops, skb, in, out);
		break;
	default:
		nft_set_pktinfo(&pkt, ops, skb, in, out);
		break;
	}

	return nft_do_chain(&pkt, ops);
}

static struct nft_af_info nft_af_bridge __read_mostly = {
	.family		= NFPROTO_BRIDGE,
	.nhooks		= NF_BR_NUMHOOKS,
	.owner		= THIS_MODULE,
	.nops		= 1,
	.hooks		= {
		[NF_BR_PRE_ROUTING]	= nft_do_chain_bridge,
		[NF_BR_LOCAL_IN]	= nft_do_chain_bridge,
		[NF_BR_FORWARD]		= nft_do_chain_bridge,
		[NF_BR_LOCAL_OUT]	= nft_do_chain_bridge,
		[NF_BR_POST_ROUTING]	= nft_do_chain_bridge,
	},
};

static int nf_tables_bridge_init_net(struct net *net)
{
	net->nft.bridge = kmalloc(sizeof(struct nft_af_info), GFP_KERNEL);
	if (net->nft.bridge == NULL)
		return -ENOMEM;

	memcpy(net->nft.bridge, &nft_af_bridge, sizeof(nft_af_bridge));

	if (nft_register_afinfo(net, net->nft.bridge) < 0)
		goto err;

	return 0;
err:
	kfree(net->nft.bridge);
	return -ENOMEM;
}

static void nf_tables_bridge_exit_net(struct net *net)
{
	nft_unregister_afinfo(net->nft.bridge);
	kfree(net->nft.bridge);
}

static struct pernet_operations nf_tables_bridge_net_ops = {
	.init	= nf_tables_bridge_init_net,
	.exit	= nf_tables_bridge_exit_net,
};

static const struct nf_chain_type filter_bridge = {
	.name		= "filter",
	.type		= NFT_CHAIN_T_DEFAULT,
	.family		= NFPROTO_BRIDGE,
	.owner		= THIS_MODULE,
	.hook_mask	= (1 << NF_BR_PRE_ROUTING) |
			  (1 << NF_BR_LOCAL_IN) |
			  (1 << NF_BR_FORWARD) |
			  (1 << NF_BR_LOCAL_OUT) |
			  (1 << NF_BR_POST_ROUTING),
};

static int __init nf_tables_bridge_init(void)
{
	int ret;

	nft_register_chain_type(&filter_bridge);
	ret = register_pernet_subsys(&nf_tables_bridge_net_ops);
	if (ret < 0)
		nft_unregister_chain_type(&filter_bridge);

	return ret;
}

static void __exit nf_tables_bridge_exit(void)
{
	unregister_pernet_subsys(&nf_tables_bridge_net_ops);
	nft_unregister_chain_type(&filter_bridge);
}

module_init(nf_tables_bridge_init);
module_exit(nf_tables_bridge_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_FAMILY(AF_BRIDGE);