CRED: Use creds in file structs
[linux-3.10.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 xt_match_param *par)
25 {
26         const struct ipt_owner_info *info = par->matchinfo;
27         const struct file *filp;
28
29         if (skb->sk == NULL || skb->sk->sk_socket == NULL)
30                 return false;
31
32         filp = skb->sk->sk_socket->file;
33         if (filp == NULL)
34                 return false;
35
36         if (info->match & IPT_OWNER_UID)
37                 if ((filp->f_cred->fsuid != info->uid) ^
38                     !!(info->invert & IPT_OWNER_UID))
39                         return false;
40
41         if (info->match & IPT_OWNER_GID)
42                 if ((filp->f_cred->fsgid != info->gid) ^
43                     !!(info->invert & IPT_OWNER_GID))
44                         return false;
45
46         return true;
47 }
48
49 static bool
50 owner_mt6_v0(const struct sk_buff *skb, const struct xt_match_param *par)
51 {
52         const struct ip6t_owner_info *info = par->matchinfo;
53         const struct file *filp;
54
55         if (skb->sk == NULL || skb->sk->sk_socket == NULL)
56                 return false;
57
58         filp = skb->sk->sk_socket->file;
59         if (filp == NULL)
60                 return false;
61
62         if (info->match & IP6T_OWNER_UID)
63                 if ((filp->f_cred->fsuid != info->uid) ^
64                     !!(info->invert & IP6T_OWNER_UID))
65                         return false;
66
67         if (info->match & IP6T_OWNER_GID)
68                 if ((filp->f_cred->fsgid != info->gid) ^
69                     !!(info->invert & IP6T_OWNER_GID))
70                         return false;
71
72         return true;
73 }
74
75 static bool
76 owner_mt(const struct sk_buff *skb, const struct xt_match_param *par)
77 {
78         const struct xt_owner_match_info *info = par->matchinfo;
79         const struct file *filp;
80
81         if (skb->sk == NULL || skb->sk->sk_socket == NULL)
82                 return (info->match ^ info->invert) == 0;
83         else if (info->match & info->invert & XT_OWNER_SOCKET)
84                 /*
85                  * Socket exists but user wanted ! --socket-exists.
86                  * (Single ampersands intended.)
87                  */
88                 return false;
89
90         filp = skb->sk->sk_socket->file;
91         if (filp == NULL)
92                 return ((info->match ^ info->invert) &
93                        (XT_OWNER_UID | XT_OWNER_GID)) == 0;
94
95         if (info->match & XT_OWNER_UID)
96                 if ((filp->f_cred->fsuid >= info->uid_min &&
97                     filp->f_cred->fsuid <= info->uid_max) ^
98                     !(info->invert & XT_OWNER_UID))
99                         return false;
100
101         if (info->match & XT_OWNER_GID)
102                 if ((filp->f_cred->fsgid >= info->gid_min &&
103                     filp->f_cred->fsgid <= info->gid_max) ^
104                     !(info->invert & XT_OWNER_GID))
105                         return false;
106
107         return true;
108 }
109
110 static bool owner_mt_check_v0(const struct xt_mtchk_param *par)
111 {
112         const struct ipt_owner_info *info = par->matchinfo;
113
114         if (info->match & (IPT_OWNER_PID | IPT_OWNER_SID | IPT_OWNER_COMM)) {
115                 printk(KERN_WARNING KBUILD_MODNAME
116                        ": PID, SID and command matching is not "
117                        "supported anymore\n");
118                 return false;
119         }
120
121         return true;
122 }
123
124 static bool owner_mt6_check_v0(const struct xt_mtchk_param *par)
125 {
126         const struct ip6t_owner_info *info = par->matchinfo;
127
128         if (info->match & (IP6T_OWNER_PID | IP6T_OWNER_SID)) {
129                 printk(KERN_WARNING KBUILD_MODNAME
130                        ": PID and SID matching is not supported anymore\n");
131                 return false;
132         }
133
134         return true;
135 }
136
137 static struct xt_match owner_mt_reg[] __read_mostly = {
138         {
139                 .name       = "owner",
140                 .revision   = 0,
141                 .family     = NFPROTO_IPV4,
142                 .match      = owner_mt_v0,
143                 .matchsize  = sizeof(struct ipt_owner_info),
144                 .checkentry = owner_mt_check_v0,
145                 .hooks      = (1 << NF_INET_LOCAL_OUT) |
146                               (1 << NF_INET_POST_ROUTING),
147                 .me         = THIS_MODULE,
148         },
149         {
150                 .name       = "owner",
151                 .revision   = 0,
152                 .family     = NFPROTO_IPV6,
153                 .match      = owner_mt6_v0,
154                 .matchsize  = sizeof(struct ip6t_owner_info),
155                 .checkentry = owner_mt6_check_v0,
156                 .hooks      = (1 << NF_INET_LOCAL_OUT) |
157                               (1 << NF_INET_POST_ROUTING),
158                 .me         = THIS_MODULE,
159         },
160         {
161                 .name       = "owner",
162                 .revision   = 1,
163                 .family     = NFPROTO_UNSPEC,
164                 .match      = owner_mt,
165                 .matchsize  = sizeof(struct xt_owner_match_info),
166                 .hooks      = (1 << NF_INET_LOCAL_OUT) |
167                               (1 << NF_INET_POST_ROUTING),
168                 .me         = THIS_MODULE,
169         },
170 };
171
172 static int __init owner_mt_init(void)
173 {
174         return xt_register_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg));
175 }
176
177 static void __exit owner_mt_exit(void)
178 {
179         xt_unregister_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg));
180 }
181
182 module_init(owner_mt_init);
183 module_exit(owner_mt_exit);
184 MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
185 MODULE_DESCRIPTION("Xtables: socket owner matching");
186 MODULE_LICENSE("GPL");
187 MODULE_ALIAS("ipt_owner");
188 MODULE_ALIAS("ip6t_owner");