summaryrefslogtreecommitdiff
path: root/net/netfilter/xt_multiport.c
blob: ac1d3c3d09e72dbbfbf49f4dcdad6fc7600dcded (plain)
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
/* Kernel module to match one of a list of TCP/UDP(-Lite)/SCTP/DCCP ports:
   ports are in the same place so we can treat them as equal. */

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <coreteam@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.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/udp.h>
#include <linux/skbuff.h>
#include <linux/in.h>

#include <linux/netfilter/xt_multiport.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("Xtables: multiple port matching for TCP, UDP, UDP-Lite, SCTP and DCCP");
MODULE_ALIAS("ipt_multiport");
MODULE_ALIAS("ip6t_multiport");

/* Returns 1 if the port is matched by the test, 0 otherwise. */
static inline bool
ports_match_v1(const struct xt_multiport_v1 *minfo,
	       u_int16_t src, u_int16_t dst)
{
	unsigned int i;
	u_int16_t s, e;

	for (i = 0; i < minfo->count; i++) {
		s = minfo->ports[i];

		if (minfo->pflags[i]) {
			/* range port matching */
			e = minfo->ports[++i];
			pr_debug("src or dst matches with %d-%d?\n", s, e);

			if (minfo->flags == XT_MULTIPORT_SOURCE
			    && src >= s && src <= e)
				return true ^ minfo->invert;
			if (minfo->flags == XT_MULTIPORT_DESTINATION
			    && dst >= s && dst <= e)
				return true ^ minfo->invert;
			if (minfo->flags == XT_MULTIPORT_EITHER
			    && ((dst >= s && dst <= e)
				|| (src >= s && src <= e)))
				return true ^ minfo->invert;
		} else {
			/* exact port matching */
			pr_debug("src or dst matches with %d?\n", s);

			if (minfo->flags == XT_MULTIPORT_SOURCE
			    && src == s)
				return true ^ minfo->invert;
			if (minfo->flags == XT_MULTIPORT_DESTINATION
			    && dst == s)
				return true ^ minfo->invert;
			if (minfo->flags == XT_MULTIPORT_EITHER
			    && (src == s || dst == s))
				return true ^ minfo->invert;
		}
	}

	return minfo->invert;
}

static bool
multiport_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const __be16 *pptr;
	__be16 _ports[2];
	const struct xt_multiport_v1 *multiinfo = par->matchinfo;

	if (par->fragoff != 0)
		return false;

	pptr = skb_header_pointer(skb, par->thoff, sizeof(_ports), _ports);
	if (pptr == NULL) {
		/* We've been asked to examine this packet, and we
		 * can't.  Hence, no choice but to drop.
		 */
		pr_debug("Dropping evil offset=0 tinygram.\n");
		par->hotdrop = true;
		return false;
	}

	return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1]));
}

static inline bool
check(u_int16_t proto,
      u_int8_t ip_invflags,
      u_int8_t match_flags,
      u_int8_t count)
{
	/* Must specify supported protocol, no unknown flags or bad count */
	return (proto == IPPROTO_TCP || proto == IPPROTO_UDP
		|| proto == IPPROTO_UDPLITE
		|| proto == IPPROTO_SCTP || proto == IPPROTO_DCCP)
		&& !(ip_invflags & XT_INV_PROTO)
		&& (match_flags == XT_MULTIPORT_SOURCE
		    || match_flags == XT_MULTIPORT_DESTINATION
		    || match_flags == XT_MULTIPORT_EITHER)
		&& count <= XT_MULTI_PORTS;
}

static int multiport_mt_check(const struct xt_mtchk_param *par)
{
	const struct ipt_ip *ip = par->entryinfo;
	const struct xt_multiport_v1 *multiinfo = par->matchinfo;

	return check(ip->proto, ip->invflags, multiinfo->flags,
		     multiinfo->count) ? 0 : -EINVAL;
}

static int multiport_mt6_check(const struct xt_mtchk_param *par)
{
	const struct ip6t_ip6 *ip = par->entryinfo;
	const struct xt_multiport_v1 *multiinfo = par->matchinfo;

	return check(ip->proto, ip->invflags, multiinfo->flags,
		     multiinfo->count) ? 0 : -EINVAL;
}

static struct xt_match multiport_mt_reg[] __read_mostly = {
	{
		.name		= "multiport",
		.family		= NFPROTO_IPV4,
		.revision	= 1,
		.checkentry	= multiport_mt_check,
		.match		= multiport_mt,
		.matchsize	= sizeof(struct xt_multiport_v1),
		.me		= THIS_MODULE,
	},
	{
		.name		= "multiport",
		.family		= NFPROTO_IPV6,
		.revision	= 1,
		.checkentry	= multiport_mt6_check,
		.match		= multiport_mt,
		.matchsize	= sizeof(struct xt_multiport_v1),
		.me		= THIS_MODULE,
	},
};

static int __init multiport_mt_init(void)
{
	return xt_register_matches(multiport_mt_reg,
	       ARRAY_SIZE(multiport_mt_reg));
}

static void __exit multiport_mt_exit(void)
{
	xt_unregister_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg));
}

module_init(multiport_mt_init);
module_exit(multiport_mt_exit);