1 /*
2 * Kernel module to match various things tied to sockets associated with
3 * locally generated outgoing packets.
4 *
5 * (C) 2000 Marc Boucher <marc@mbsi.ca>
6 *
7 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
8 * <jengelh@computergmbh.de>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/file.h>
17 #include <net/sock.h>
18 #include <linux/netfilter/x_tables.h>
19 #include <linux/netfilter/xt_owner.h>
20 #include <linux/netfilter_ipv4/ipt_owner.h>
21 #include <linux/netfilter_ipv6/ip6t_owner.h>
22
23 static bool
24 owner_mt_v0(const struct sk_buff *skb, const struct net_device *in,
25 const struct net_device *out, const struct xt_match *match,
26 const void *matchinfo, int offset, unsigned int protoff,
27 bool *hotdrop)
28 {
29 const struct ipt_owner_info *info = matchinfo;
30 const struct file *filp;
31
32 if (skb->sk == NULL || skb->sk->sk_socket == NULL)
33 return false;
34
35 filp = skb->sk->sk_socket->file;
36 if (filp == NULL)
37 return false;
38
39 if (info->match & IPT_OWNER_UID)
40 if ((filp->f_uid != info->uid) ^
41 !!(info->invert & IPT_OWNER_UID))
42 return false;
43
44 if (info->match & IPT_OWNER_GID)
45 if ((filp->f_gid != info->gid) ^
46 !!(info->invert & IPT_OWNER_GID))
47 return false;
48
49 return true;
50 }
51
52 static bool
53 owner_mt6_v0(const struct sk_buff *skb, const struct net_device *in,
54 const struct net_device *out, const struct xt_match *match,
55 const void *matchinfo, int offset, unsigned int protoff,
56 bool *hotdrop)
57 {
58 const struct ip6t_owner_info *info = matchinfo;
59 const struct file *filp;
60
61 if (skb->sk == NULL || skb->sk->sk_socket == NULL)
62 return false;
63
64 filp = skb->sk->sk_socket->file;
65 if (filp == NULL)
66 return false;
67
68 if (info->match & IP6T_OWNER_UID)
69 if ((filp->f_uid != info->uid) ^
70 !!(info->invert & IP6T_OWNER_UID))
71 return false;
72
73 if (info->match & IP6T_OWNER_GID)
74 if ((filp->f_gid != info->gid) ^
75 !!(info->invert & IP6T_OWNER_GID))
76 return false;
77
78 return true;
79 }
80
81 static bool
82 owner_mt(const struct sk_buff *skb, const struct net_device *in,
83 const struct net_device *out, const struct xt_match *match,
84 const void *matchinfo, int offset, unsigned int protoff,
85 bool *hotdrop)
86 {
87 const struct xt_owner_match_info *info = matchinfo;
88 const struct file *filp;
89
90 if (skb->sk == NULL || skb->sk->sk_socket == NULL)
91 return (info->match ^ info->invert) == 0;
92 else if (info->match & info->invert & XT_OWNER_SOCKET)
93 /*
94 * Socket exists but user wanted ! --socket-exists.
95 * (Single ampersands intended.)
96 */
97 return false;
98
99 filp = skb->sk->sk_socket->file;
100 if (filp == NULL)
101 return ((info->match ^ info->invert) &
102 (XT_OWNER_UID | XT_OWNER_GID)) == 0;
103
104 if (info->match & XT_OWNER_UID)
105 if ((filp->f_uid >= info->uid_min &&
106 filp->f_uid <= info->uid_max) ^
107 !(info->invert & XT_OWNER_UID))
108 return false;
109
110 if (info->match & XT_OWNER_GID)
111 if ((filp->f_gid >= info->gid_min &&
112 filp->f_gid <= info->gid_max) ^
113 !(info->invert & XT_OWNER_GID))
114 return false;
115
116 return true;
117 }
118
119 static bool
120 owner_mt_check_v0(const char *tablename, const void *ip,
121 const struct xt_match *match, void *matchinfo,
122 unsigned int hook_mask)
123 {
124 const struct ipt_owner_info *info = matchinfo;
125
126 if (info->match & (IPT_OWNER_PID | IPT_OWNER_SID | IPT_OWNER_COMM)) {
127 printk(KERN_WARNING KBUILD_MODNAME
128 ": PID, SID and command matching is not "
129 "supported anymore\n");
130 return false;
131 }
132
133 return true;
134 }
135
136 static bool
137 owner_mt6_check_v0(const char *tablename, const void *ip,
138 const struct xt_match *match, void *matchinfo,
139 unsigned int hook_mask)
140 {
141 const struct ip6t_owner_info *info = matchinfo;
142
143 if (info->match & (IP6T_OWNER_PID | IP6T_OWNER_SID)) {
144 printk(KERN_WARNING KBUILD_MODNAME
145 ": PID and SID matching is not supported anymore\n");
146 return false;
147 }
148
149 return true;
150 }
151
152 static struct xt_match owner_mt_reg[] __read_mostly = {
153 {
154 .name = "owner",
155 .revision = 0,
156 .family = AF_INET,
157 .match = owner_mt_v0,
158 .matchsize = sizeof(struct ipt_owner_info),
159 .checkentry = owner_mt_check_v0,
160 .hooks = (1 << NF_INET_LOCAL_OUT) |
161 (1 << NF_INET_POST_ROUTING),
162 .me = THIS_MODULE,
163 },
164 {
165 .name = "owner",
166 .revision = 0,
167 .family = AF_INET6,
168 .match = owner_mt6_v0,
169 .matchsize = sizeof(struct ip6t_owner_info),
170 .checkentry = owner_mt6_check_v0,
171 .hooks = (1 << NF_INET_LOCAL_OUT) |
172 (1 << NF_INET_POST_ROUTING),
173 .me = THIS_MODULE,
174 },
175 {
176 .name = "owner",
177 .revision = 1,
178 .family = AF_INET,
179 .match = owner_mt,
180 .matchsize = sizeof(struct xt_owner_match_info),
181 .hooks = (1 << NF_INET_LOCAL_OUT) |
182 (1 << NF_INET_POST_ROUTING),
183 .me = THIS_MODULE,
184 },
185 {
186 .name = "owner",
187 .revision = 1,
188 .family = AF_INET6,
189 .match = owner_mt,
190 .matchsize = sizeof(struct xt_owner_match_info),
191 .hooks = (1 << NF_INET_LOCAL_OUT) |
192 (1 << NF_INET_POST_ROUTING),
193 .me = THIS_MODULE,
194 },
195 };
196
197 static int __init owner_mt_init(void)
198 {
199 return xt_register_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg));
200 }
201
202 static void __exit owner_mt_exit(void)
203 {
204 xt_unregister_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg));
205 }
206
207 module_init(owner_mt_init);
208 module_exit(owner_mt_exit);
209 MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
210 MODULE_DESCRIPTION("Xtables: socket owner matching");
211 MODULE_LICENSE("GPL");
212 MODULE_ALIAS("ipt_owner");
213 MODULE_ALIAS("ip6t_owner");
214
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