summaryrefslogtreecommitdiff
path: root/net/netfilter/xt_owner.c
blob: d1c3b7ae9b494a8c1b13050250a0a47d84ce8491 (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
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
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
/*
 * Kernel module to match various things tied to sockets associated with
 * locally generated outgoing packets.
 *
 * (C) 2000 Marc Boucher <marc@mbsi.ca>
 *
 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
 * <jengelh@computergmbh.de>
 *
 * 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/skbuff.h>
#include <linux/file.h>
#include <net/sock.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_owner.h>
#include <linux/netfilter_ipv4/ipt_owner.h>
#include <linux/netfilter_ipv6/ip6t_owner.h>

static bool
owner_mt_v0(const struct sk_buff *skb, const struct net_device *in,
            const struct net_device *out, const struct xt_match *match,
            const void *matchinfo, int offset, unsigned int protoff,
            bool *hotdrop)
{
	const struct ipt_owner_info *info = matchinfo;
	const struct file *filp;

	if (skb->sk == NULL || skb->sk->sk_socket == NULL)
		return false;

	filp = skb->sk->sk_socket->file;
	if (filp == NULL)
		return false;

	if (info->match & IPT_OWNER_UID)
		if ((filp->f_uid != info->uid) ^
		    !!(info->invert & IPT_OWNER_UID))
			return false;

	if (info->match & IPT_OWNER_GID)
		if ((filp->f_gid != info->gid) ^
		    !!(info->invert & IPT_OWNER_GID))
			return false;

	return true;
}

static bool
owner_mt6_v0(const struct sk_buff *skb, const struct net_device *in,
             const struct net_device *out, const struct xt_match *match,
             const void *matchinfo, int offset, unsigned int protoff,
             bool *hotdrop)
{
	const struct ip6t_owner_info *info = matchinfo;
	const struct file *filp;

	if (skb->sk == NULL || skb->sk->sk_socket == NULL)
		return false;

	filp = skb->sk->sk_socket->file;
	if (filp == NULL)
		return false;

	if (info->match & IP6T_OWNER_UID)
		if ((filp->f_uid != info->uid) ^
		    !!(info->invert & IP6T_OWNER_UID))
			return false;

	if (info->match & IP6T_OWNER_GID)
		if ((filp->f_gid != info->gid) ^
		    !!(info->invert & IP6T_OWNER_GID))
			return false;

	return true;
}

static bool
owner_mt(const struct sk_buff *skb, const struct net_device *in,
         const struct net_device *out, const struct xt_match *match,
         const void *matchinfo, int offset, unsigned int protoff,
         bool *hotdrop)
{
	const struct xt_owner_match_info *info = matchinfo;
	const struct file *filp;

	if (skb->sk == NULL || skb->sk->sk_socket == NULL)
		return (info->match ^ info->invert) == 0;
	else if (info->match & info->invert & XT_OWNER_SOCKET)
		/*
		 * Socket exists but user wanted ! --socket-exists.
		 * (Single ampersands intended.)
		 */
		return false;

	filp = skb->sk->sk_socket->file;
	if (filp == NULL)
		return ((info->match ^ info->invert) &
		       (XT_OWNER_UID | XT_OWNER_GID)) == 0;

	if (info->match & XT_OWNER_UID)
		if ((filp->f_uid >= info->uid_min &&
		    filp->f_uid <= info->uid_max) ^
		    !(info->invert & XT_OWNER_UID))
			return false;

	if (info->match & XT_OWNER_GID)
		if ((filp->f_gid >= info->gid_min &&
		    filp->f_gid <= info->gid_max) ^
		    !(info->invert & XT_OWNER_GID))
			return false;

	return true;
}

static bool
owner_mt_check_v0(const char *tablename, const void *ip,
                  const struct xt_match *match, void *matchinfo,
                  unsigned int hook_mask)
{
	const struct ipt_owner_info *info = matchinfo;

	if (info->match & (IPT_OWNER_PID | IPT_OWNER_SID | IPT_OWNER_COMM)) {
		printk(KERN_WARNING KBUILD_MODNAME
		       ": PID, SID and command matching is not "
		       "supported anymore\n");
		return false;
	}

	return true;
}

static bool
owner_mt6_check_v0(const char *tablename, const void *ip,
                   const struct xt_match *match, void *matchinfo,
                   unsigned int hook_mask)
{
	const struct ip6t_owner_info *info = matchinfo;

	if (info->match & (IP6T_OWNER_PID | IP6T_OWNER_SID)) {
		printk(KERN_WARNING KBUILD_MODNAME
		       ": PID and SID matching is not supported anymore\n");
		return false;
	}

	return true;
}

static struct xt_match owner_mt_reg[] __read_mostly = {
	{
		.name       = "owner",
		.revision   = 0,
		.family     = NFPROTO_IPV4,
		.match      = owner_mt_v0,
		.matchsize  = sizeof(struct ipt_owner_info),
		.checkentry = owner_mt_check_v0,
		.hooks      = (1 << NF_INET_LOCAL_OUT) |
		              (1 << NF_INET_POST_ROUTING),
		.me         = THIS_MODULE,
	},
	{
		.name       = "owner",
		.revision   = 0,
		.family     = NFPROTO_IPV6,
		.match      = owner_mt6_v0,
		.matchsize  = sizeof(struct ip6t_owner_info),
		.checkentry = owner_mt6_check_v0,
		.hooks      = (1 << NF_INET_LOCAL_OUT) |
		              (1 << NF_INET_POST_ROUTING),
		.me         = THIS_MODULE,
	},
	{
		.name       = "owner",
		.revision   = 1,
		.family     = NFPROTO_IPV4,
		.match      = owner_mt,
		.matchsize  = sizeof(struct xt_owner_match_info),
		.hooks      = (1 << NF_INET_LOCAL_OUT) |
		              (1 << NF_INET_POST_ROUTING),
		.me         = THIS_MODULE,
	},
	{
		.name       = "owner",
		.revision   = 1,
		.family     = NFPROTO_IPV6,
		.match      = owner_mt,
		.matchsize  = sizeof(struct xt_owner_match_info),
		.hooks      = (1 << NF_INET_LOCAL_OUT) |
		              (1 << NF_INET_POST_ROUTING),
		.me         = THIS_MODULE,
	},
};

static int __init owner_mt_init(void)
{
	return xt_register_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg));
}

static void __exit owner_mt_exit(void)
{
	xt_unregister_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg));
}

module_init(owner_mt_init);
module_exit(owner_mt_exit);
MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
MODULE_DESCRIPTION("Xtables: socket owner matching");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_owner");
MODULE_ALIAS("ip6t_owner");