Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/kaber/nf-next-2.6
[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  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/file.h>
16 #include <net/sock.h>
17 #include <linux/netfilter/x_tables.h>
18 #include <linux/netfilter/xt_owner.h>
19
20 static bool
21 owner_mt(const struct sk_buff *skb, const struct xt_match_param *par)
22 {
23         const struct xt_owner_match_info *info = par->matchinfo;
24         const struct file *filp;
25
26         if (skb->sk == NULL || skb->sk->sk_socket == NULL)
27                 return (info->match ^ info->invert) == 0;
28         else if (info->match & info->invert & XT_OWNER_SOCKET)
29                 /*
30                  * Socket exists but user wanted ! --socket-exists.
31                  * (Single ampersands intended.)
32                  */
33                 return false;
34
35         filp = skb->sk->sk_socket->file;
36         if (filp == NULL)
37                 return ((info->match ^ info->invert) &
38                        (XT_OWNER_UID | XT_OWNER_GID)) == 0;
39
40         if (info->match & XT_OWNER_UID)
41                 if ((filp->f_cred->fsuid >= info->uid_min &&
42                     filp->f_cred->fsuid <= info->uid_max) ^
43                     !(info->invert & XT_OWNER_UID))
44                         return false;
45
46         if (info->match & XT_OWNER_GID)
47                 if ((filp->f_cred->fsgid >= info->gid_min &&
48                     filp->f_cred->fsgid <= info->gid_max) ^
49                     !(info->invert & XT_OWNER_GID))
50                         return false;
51
52         return true;
53 }
54
55 static struct xt_match owner_mt_reg __read_mostly = {
56         .name       = "owner",
57         .revision   = 1,
58         .family     = NFPROTO_UNSPEC,
59         .match      = owner_mt,
60         .matchsize  = sizeof(struct xt_owner_match_info),
61         .hooks      = (1 << NF_INET_LOCAL_OUT) |
62                       (1 << NF_INET_POST_ROUTING),
63         .me         = THIS_MODULE,
64 };
65
66 static int __init owner_mt_init(void)
67 {
68         return xt_register_match(&owner_mt_reg);
69 }
70
71 static void __exit owner_mt_exit(void)
72 {
73         xt_unregister_match(&owner_mt_reg);
74 }
75
76 module_init(owner_mt_init);
77 module_exit(owner_mt_exit);
78 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
79 MODULE_DESCRIPTION("Xtables: socket owner matching");
80 MODULE_LICENSE("GPL");
81 MODULE_ALIAS("ipt_owner");
82 MODULE_ALIAS("ip6t_owner");