Commit | Line | Data |
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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 | * | |
edc26f7a | 7 | * Copyright © CC Computer Consultants GmbH, 2007 - 2008 |
0265ab44 JE |
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> | |
0265ab44 | 19 | |
26711a79 EB |
20 | static int owner_check(const struct xt_mtchk_param *par) |
21 | { | |
22 | struct xt_owner_match_info *info = par->matchinfo; | |
23 | ||
24 | /* For now only allow adding matches from the initial user namespace */ | |
25 | if ((info->match & (XT_OWNER_UID|XT_OWNER_GID)) && | |
26 | (current_user_ns() != &init_user_ns)) | |
27 | return -EINVAL; | |
28 | return 0; | |
29 | } | |
30 | ||
0265ab44 | 31 | static bool |
62fc8051 | 32 | owner_mt(const struct sk_buff *skb, struct xt_action_param *par) |
0265ab44 | 33 | { |
f7108a20 | 34 | const struct xt_owner_match_info *info = par->matchinfo; |
0265ab44 JE |
35 | const struct file *filp; |
36 | ||
37 | if (skb->sk == NULL || skb->sk->sk_socket == NULL) | |
38 | return (info->match ^ info->invert) == 0; | |
39 | else if (info->match & info->invert & XT_OWNER_SOCKET) | |
40 | /* | |
41 | * Socket exists but user wanted ! --socket-exists. | |
42 | * (Single ampersands intended.) | |
43 | */ | |
44 | return false; | |
45 | ||
46 | filp = skb->sk->sk_socket->file; | |
47 | if (filp == NULL) | |
48 | return ((info->match ^ info->invert) & | |
49 | (XT_OWNER_UID | XT_OWNER_GID)) == 0; | |
50 | ||
26711a79 EB |
51 | if (info->match & XT_OWNER_UID) { |
52 | kuid_t uid_min = make_kuid(&init_user_ns, info->uid_min); | |
53 | kuid_t uid_max = make_kuid(&init_user_ns, info->uid_max); | |
54 | if ((uid_gte(filp->f_cred->fsuid, uid_min) && | |
55 | uid_lte(filp->f_cred->fsuid, uid_max)) ^ | |
edc26f7a | 56 | !(info->invert & XT_OWNER_UID)) |
0265ab44 | 57 | return false; |
26711a79 | 58 | } |
0265ab44 | 59 | |
26711a79 EB |
60 | if (info->match & XT_OWNER_GID) { |
61 | kgid_t gid_min = make_kgid(&init_user_ns, info->gid_min); | |
62 | kgid_t gid_max = make_kgid(&init_user_ns, info->gid_max); | |
63 | if ((gid_gte(filp->f_cred->fsgid, gid_min) && | |
64 | gid_lte(filp->f_cred->fsgid, gid_max)) ^ | |
edc26f7a | 65 | !(info->invert & XT_OWNER_GID)) |
0265ab44 | 66 | return false; |
26711a79 | 67 | } |
0265ab44 JE |
68 | |
69 | return true; | |
70 | } | |
71 | ||
6461caed JE |
72 | static struct xt_match owner_mt_reg __read_mostly = { |
73 | .name = "owner", | |
74 | .revision = 1, | |
75 | .family = NFPROTO_UNSPEC, | |
26711a79 | 76 | .checkentry = owner_check, |
6461caed JE |
77 | .match = owner_mt, |
78 | .matchsize = sizeof(struct xt_owner_match_info), | |
79 | .hooks = (1 << NF_INET_LOCAL_OUT) | | |
80 | (1 << NF_INET_POST_ROUTING), | |
81 | .me = THIS_MODULE, | |
0265ab44 JE |
82 | }; |
83 | ||
84 | static int __init owner_mt_init(void) | |
85 | { | |
6461caed | 86 | return xt_register_match(&owner_mt_reg); |
0265ab44 JE |
87 | } |
88 | ||
89 | static void __exit owner_mt_exit(void) | |
90 | { | |
6461caed | 91 | xt_unregister_match(&owner_mt_reg); |
0265ab44 JE |
92 | } |
93 | ||
94 | module_init(owner_mt_init); | |
95 | module_exit(owner_mt_exit); | |
6461caed | 96 | MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); |
2ae15b64 | 97 | MODULE_DESCRIPTION("Xtables: socket owner matching"); |
0265ab44 JE |
98 | MODULE_LICENSE("GPL"); |
99 | MODULE_ALIAS("ipt_owner"); | |
100 | MODULE_ALIAS("ip6t_owner"); |