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0265ab44 JE |
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 | |
8 | * Contact: <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) ^ | |
106 | !!(info->invert & XT_OWNER_UID)) | |
107 | return false; | |
108 | ||
109 | if (info->match & XT_OWNER_GID) | |
110 | if ((filp->f_gid != info->gid) ^ | |
111 | !!(info->invert & XT_OWNER_GID)) | |
112 | return false; | |
113 | ||
114 | return true; | |
115 | } | |
116 | ||
117 | static bool | |
118 | owner_mt_check_v0(const char *tablename, const void *ip, | |
119 | const struct xt_match *match, void *matchinfo, | |
120 | unsigned int hook_mask) | |
121 | { | |
122 | const struct ipt_owner_info *info = matchinfo; | |
123 | ||
124 | if (info->match & (IPT_OWNER_PID | IPT_OWNER_SID | IPT_OWNER_COMM)) { | |
125 | printk(KERN_WARNING KBUILD_MODNAME | |
126 | ": PID, SID and command matching is not " | |
127 | "supported anymore\n"); | |
128 | return false; | |
129 | } | |
130 | ||
131 | return true; | |
132 | } | |
133 | ||
134 | static bool | |
135 | owner_mt6_check_v0(const char *tablename, const void *ip, | |
136 | const struct xt_match *match, void *matchinfo, | |
137 | unsigned int hook_mask) | |
138 | { | |
139 | const struct ip6t_owner_info *info = matchinfo; | |
140 | ||
141 | if (info->match & (IP6T_OWNER_PID | IP6T_OWNER_SID)) { | |
142 | printk(KERN_WARNING KBUILD_MODNAME | |
143 | ": PID and SID matching is not supported anymore\n"); | |
144 | return false; | |
145 | } | |
146 | ||
147 | return true; | |
148 | } | |
149 | ||
150 | static struct xt_match owner_mt_reg[] __read_mostly = { | |
151 | { | |
152 | .name = "owner", | |
153 | .revision = 0, | |
154 | .family = AF_INET, | |
155 | .match = owner_mt_v0, | |
156 | .matchsize = sizeof(struct ipt_owner_info), | |
157 | .checkentry = owner_mt_check_v0, | |
158 | .hooks = (1 << NF_INET_LOCAL_OUT) | | |
159 | (1 << NF_INET_POST_ROUTING), | |
160 | .me = THIS_MODULE, | |
161 | }, | |
162 | { | |
163 | .name = "owner", | |
164 | .revision = 0, | |
165 | .family = AF_INET6, | |
166 | .match = owner_mt6_v0, | |
167 | .matchsize = sizeof(struct ip6t_owner_info), | |
168 | .checkentry = owner_mt6_check_v0, | |
169 | .hooks = (1 << NF_INET_LOCAL_OUT) | | |
170 | (1 << NF_INET_POST_ROUTING), | |
171 | .me = THIS_MODULE, | |
172 | }, | |
173 | { | |
174 | .name = "owner", | |
175 | .revision = 1, | |
176 | .family = AF_INET, | |
177 | .match = owner_mt, | |
178 | .matchsize = sizeof(struct xt_owner_match_info), | |
179 | .hooks = (1 << NF_INET_LOCAL_OUT) | | |
180 | (1 << NF_INET_POST_ROUTING), | |
181 | .me = THIS_MODULE, | |
182 | }, | |
183 | { | |
184 | .name = "owner", | |
185 | .revision = 1, | |
186 | .family = AF_INET6, | |
187 | .match = owner_mt, | |
188 | .matchsize = sizeof(struct xt_owner_match_info), | |
189 | .hooks = (1 << NF_INET_LOCAL_OUT) | | |
190 | (1 << NF_INET_POST_ROUTING), | |
191 | .me = THIS_MODULE, | |
192 | }, | |
193 | }; | |
194 | ||
195 | static int __init owner_mt_init(void) | |
196 | { | |
197 | return xt_register_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg)); | |
198 | } | |
199 | ||
200 | static void __exit owner_mt_exit(void) | |
201 | { | |
202 | xt_unregister_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg)); | |
203 | } | |
204 | ||
205 | module_init(owner_mt_init); | |
206 | module_exit(owner_mt_exit); | |
207 | MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>"); | |
2ae15b64 | 208 | MODULE_DESCRIPTION("Xtables: socket owner matching"); |
0265ab44 JE |
209 | MODULE_LICENSE("GPL"); |
210 | MODULE_ALIAS("ipt_owner"); | |
211 | MODULE_ALIAS("ip6t_owner"); |