[NETFILTER]: annotate {arp,ip,ip6,x}tables with const
[linux-2.6.git] / net / netfilter / xt_owner.c
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");