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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 <net/inet_sock.h>
18#include <linux/netfilter/x_tables.h>
19#include <linux/netfilter/xt_owner.h>
20
21static int owner_check(const struct xt_mtchk_param *par)
22{
23 struct xt_owner_match_info *info = par->matchinfo;
24 struct net *net = par->net;
25
26 /* Only allow the common case where the userns of the writer
27 * matches the userns of the network namespace.
28 */
29 if ((info->match & (XT_OWNER_UID|XT_OWNER_GID)) &&
30 (current_user_ns() != net->user_ns))
31 return -EINVAL;
32
33 /* Ensure the uids are valid */
34 if (info->match & XT_OWNER_UID) {
35 kuid_t uid_min = make_kuid(net->user_ns, info->uid_min);
36 kuid_t uid_max = make_kuid(net->user_ns, info->uid_max);
37
38 if (!uid_valid(uid_min) || !uid_valid(uid_max) ||
39 (info->uid_max < info->uid_min) ||
40 uid_lt(uid_max, uid_min)) {
41 return -EINVAL;
42 }
43 }
44
45 /* Ensure the gids are valid */
46 if (info->match & XT_OWNER_GID) {
47 kgid_t gid_min = make_kgid(net->user_ns, info->gid_min);
48 kgid_t gid_max = make_kgid(net->user_ns, info->gid_max);
49
50 if (!gid_valid(gid_min) || !gid_valid(gid_max) ||
51 (info->gid_max < info->gid_min) ||
52 gid_lt(gid_max, gid_min)) {
53 return -EINVAL;
54 }
55 }
56
57 return 0;
58}
59
60static bool
61owner_mt(const struct sk_buff *skb, struct xt_action_param *par)
62{
63 const struct xt_owner_match_info *info = par->matchinfo;
64 const struct file *filp;
65 struct sock *sk = skb_to_full_sk(skb);
66 struct net *net = xt_net(par);
67
68 if (sk == NULL || sk->sk_socket == NULL)
69 return (info->match ^ info->invert) == 0;
70 else if (info->match & info->invert & XT_OWNER_SOCKET)
71 /*
72 * Socket exists but user wanted ! --socket-exists.
73 * (Single ampersands intended.)
74 */
75 return false;
76
77 filp = sk->sk_socket->file;
78 if (filp == NULL)
79 return ((info->match ^ info->invert) &
80 (XT_OWNER_UID | XT_OWNER_GID)) == 0;
81
82 if (info->match & XT_OWNER_UID) {
83 kuid_t uid_min = make_kuid(net->user_ns, info->uid_min);
84 kuid_t uid_max = make_kuid(net->user_ns, info->uid_max);
85 if ((uid_gte(filp->f_cred->fsuid, uid_min) &&
86 uid_lte(filp->f_cred->fsuid, uid_max)) ^
87 !(info->invert & XT_OWNER_UID))
88 return false;
89 }
90
91 if (info->match & XT_OWNER_GID) {
92 kgid_t gid_min = make_kgid(net->user_ns, info->gid_min);
93 kgid_t gid_max = make_kgid(net->user_ns, info->gid_max);
94 if ((gid_gte(filp->f_cred->fsgid, gid_min) &&
95 gid_lte(filp->f_cred->fsgid, gid_max)) ^
96 !(info->invert & XT_OWNER_GID))
97 return false;
98 }
99
100 return true;
101}
102
103static struct xt_match owner_mt_reg __read_mostly = {
104 .name = "owner",
105 .revision = 1,
106 .family = NFPROTO_UNSPEC,
107 .checkentry = owner_check,
108 .match = owner_mt,
109 .matchsize = sizeof(struct xt_owner_match_info),
110 .hooks = (1 << NF_INET_LOCAL_OUT) |
111 (1 << NF_INET_POST_ROUTING),
112 .me = THIS_MODULE,
113};
114
115static int __init owner_mt_init(void)
116{
117 return xt_register_match(&owner_mt_reg);
118}
119
120static void __exit owner_mt_exit(void)
121{
122 xt_unregister_match(&owner_mt_reg);
123}
124
125module_init(owner_mt_init);
126module_exit(owner_mt_exit);
127MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
128MODULE_DESCRIPTION("Xtables: socket owner matching");
129MODULE_LICENSE("GPL");
130MODULE_ALIAS("ipt_owner");
131MODULE_ALIAS("ip6t_owner");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Kernel module to match various things tied to sockets associated with
4 * locally generated outgoing packets.
5 *
6 * (C) 2000 Marc Boucher <marc@mbsi.ca>
7 *
8 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
9 */
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/file.h>
13#include <linux/cred.h>
14
15#include <net/sock.h>
16#include <net/inet_sock.h>
17#include <linux/netfilter/x_tables.h>
18#include <linux/netfilter/xt_owner.h>
19
20static int owner_check(const struct xt_mtchk_param *par)
21{
22 struct xt_owner_match_info *info = par->matchinfo;
23 struct net *net = par->net;
24
25 if (info->match & ~XT_OWNER_MASK)
26 return -EINVAL;
27
28 /* Only allow the common case where the userns of the writer
29 * matches the userns of the network namespace.
30 */
31 if ((info->match & (XT_OWNER_UID|XT_OWNER_GID)) &&
32 (current_user_ns() != net->user_ns))
33 return -EINVAL;
34
35 /* Ensure the uids are valid */
36 if (info->match & XT_OWNER_UID) {
37 kuid_t uid_min = make_kuid(net->user_ns, info->uid_min);
38 kuid_t uid_max = make_kuid(net->user_ns, info->uid_max);
39
40 if (!uid_valid(uid_min) || !uid_valid(uid_max) ||
41 (info->uid_max < info->uid_min) ||
42 uid_lt(uid_max, uid_min)) {
43 return -EINVAL;
44 }
45 }
46
47 /* Ensure the gids are valid */
48 if (info->match & XT_OWNER_GID) {
49 kgid_t gid_min = make_kgid(net->user_ns, info->gid_min);
50 kgid_t gid_max = make_kgid(net->user_ns, info->gid_max);
51
52 if (!gid_valid(gid_min) || !gid_valid(gid_max) ||
53 (info->gid_max < info->gid_min) ||
54 gid_lt(gid_max, gid_min)) {
55 return -EINVAL;
56 }
57 }
58
59 return 0;
60}
61
62static bool
63owner_mt(const struct sk_buff *skb, struct xt_action_param *par)
64{
65 const struct xt_owner_match_info *info = par->matchinfo;
66 const struct file *filp;
67 struct sock *sk = skb_to_full_sk(skb);
68 struct net *net = xt_net(par);
69
70 if (!sk || !sk->sk_socket || !net_eq(net, sock_net(sk)))
71 return (info->match ^ info->invert) == 0;
72 else if (info->match & info->invert & XT_OWNER_SOCKET)
73 /*
74 * Socket exists but user wanted ! --socket-exists.
75 * (Single ampersands intended.)
76 */
77 return false;
78
79 read_lock_bh(&sk->sk_callback_lock);
80 filp = sk->sk_socket ? sk->sk_socket->file : NULL;
81 if (filp == NULL) {
82 read_unlock_bh(&sk->sk_callback_lock);
83 return ((info->match ^ info->invert) &
84 (XT_OWNER_UID | XT_OWNER_GID)) == 0;
85 }
86
87 if (info->match & XT_OWNER_UID) {
88 kuid_t uid_min = make_kuid(net->user_ns, info->uid_min);
89 kuid_t uid_max = make_kuid(net->user_ns, info->uid_max);
90 if ((uid_gte(filp->f_cred->fsuid, uid_min) &&
91 uid_lte(filp->f_cred->fsuid, uid_max)) ^
92 !(info->invert & XT_OWNER_UID)) {
93 read_unlock_bh(&sk->sk_callback_lock);
94 return false;
95 }
96 }
97
98 if (info->match & XT_OWNER_GID) {
99 unsigned int i, match = false;
100 kgid_t gid_min = make_kgid(net->user_ns, info->gid_min);
101 kgid_t gid_max = make_kgid(net->user_ns, info->gid_max);
102 struct group_info *gi = filp->f_cred->group_info;
103
104 if (gid_gte(filp->f_cred->fsgid, gid_min) &&
105 gid_lte(filp->f_cred->fsgid, gid_max))
106 match = true;
107
108 if (!match && (info->match & XT_OWNER_SUPPL_GROUPS) && gi) {
109 for (i = 0; i < gi->ngroups; ++i) {
110 kgid_t group = gi->gid[i];
111
112 if (gid_gte(group, gid_min) &&
113 gid_lte(group, gid_max)) {
114 match = true;
115 break;
116 }
117 }
118 }
119
120 if (match ^ !(info->invert & XT_OWNER_GID)) {
121 read_unlock_bh(&sk->sk_callback_lock);
122 return false;
123 }
124 }
125
126 read_unlock_bh(&sk->sk_callback_lock);
127 return true;
128}
129
130static struct xt_match owner_mt_reg __read_mostly = {
131 .name = "owner",
132 .revision = 1,
133 .family = NFPROTO_UNSPEC,
134 .checkentry = owner_check,
135 .match = owner_mt,
136 .matchsize = sizeof(struct xt_owner_match_info),
137 .hooks = (1 << NF_INET_LOCAL_OUT) |
138 (1 << NF_INET_POST_ROUTING),
139 .me = THIS_MODULE,
140};
141
142static int __init owner_mt_init(void)
143{
144 return xt_register_match(&owner_mt_reg);
145}
146
147static void __exit owner_mt_exit(void)
148{
149 xt_unregister_match(&owner_mt_reg);
150}
151
152module_init(owner_mt_init);
153module_exit(owner_mt_exit);
154MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
155MODULE_DESCRIPTION("Xtables: socket owner matching");
156MODULE_LICENSE("GPL");
157MODULE_ALIAS("ipt_owner");
158MODULE_ALIAS("ip6t_owner");