[linux-2.6-block.git] / net / netfilter / xt_owner.c

/*
 * Kernel module to match various things tied to sockets associated with
 * locally generated outgoing packets.
 *
 * (C) 2000 Marc Boucher <marc@mbsi.ca>
 *
 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/file.h>
#include <net/sock.h>
#include <net/inet_sock.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_owner.h>

static int owner_check(const struct xt_mtchk_param *par)
{
	struct xt_owner_match_info *info = par->matchinfo;

	/* For now only allow adding matches from the initial user namespace */
	if ((info->match & (XT_OWNER_UID|XT_OWNER_GID)) &&
	    (current_user_ns() != &init_user_ns))
		return -EINVAL;
	return 0;
}

static bool
owner_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_owner_match_info *info = par->matchinfo;
	const struct file *filp;
	struct sock *sk = skb_to_full_sk(skb);

	if (sk == NULL || sk->sk_socket == NULL)
		return (info->match ^ info->invert) == 0;
	else if (info->match & info->invert & XT_OWNER_SOCKET)
		/*
		 * Socket exists but user wanted ! --socket-exists.
		 * (Single ampersands intended.)
		 */
		return false;

	filp = sk->sk_socket->file;
	if (filp == NULL)
		return ((info->match ^ info->invert) &
		       (XT_OWNER_UID | XT_OWNER_GID)) == 0;

	if (info->match & XT_OWNER_UID) {
		kuid_t uid_min = make_kuid(&init_user_ns, info->uid_min);
		kuid_t uid_max = make_kuid(&init_user_ns, info->uid_max);
		if ((uid_gte(filp->f_cred->fsuid, uid_min) &&
		     uid_lte(filp->f_cred->fsuid, uid_max)) ^
		    !(info->invert & XT_OWNER_UID))
			return false;
	}

	if (info->match & XT_OWNER_GID) {
		kgid_t gid_min = make_kgid(&init_user_ns, info->gid_min);
		kgid_t gid_max = make_kgid(&init_user_ns, info->gid_max);
		if ((gid_gte(filp->f_cred->fsgid, gid_min) &&
		     gid_lte(filp->f_cred->fsgid, gid_max)) ^
		    !(info->invert & XT_OWNER_GID))
			return false;
	}

	return true;
}

static struct xt_match owner_mt_reg __read_mostly = {
	.name       = "owner",
	.revision   = 1,
	.family     = NFPROTO_UNSPEC,
	.checkentry = owner_check,
	.match      = owner_mt,
	.matchsize  = sizeof(struct xt_owner_match_info),
	.hooks      = (1 << NF_INET_LOCAL_OUT) |
	              (1 << NF_INET_POST_ROUTING),
	.me         = THIS_MODULE,
};

static int __init owner_mt_init(void)
{
	return xt_register_match(&owner_mt_reg);
}

static void __exit owner_mt_exit(void)
{
	xt_unregister_match(&owner_mt_reg);
}

module_init(owner_mt_init);
module_exit(owner_mt_exit);
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
MODULE_DESCRIPTION("Xtables: socket owner matching");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_owner");
MODULE_ALIAS("ip6t_owner");
Commit	Line	Data
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>
fdd723e2	17	#include <net/inet_sock.h>
0265ab44 JE	18	#include <linux/netfilter/x_tables.h>
0265ab44 JE	19	#include <linux/netfilter/xt_owner.h>
0265ab44	20
26711a79 EB	21	static int owner_check(const struct xt_mtchk_param *par)
	22	{
	23	struct xt_owner_match_info *info = par->matchinfo;
	24
	25	/* For now only allow adding matches from the initial user namespace */
	26	if ((info->match & (XT_OWNER_UID\|XT_OWNER_GID)) &&
	27	(current_user_ns() != &init_user_ns))
	28	return -EINVAL;
	29	return 0;
	30	}
	31
0265ab44	32	static bool
62fc8051	33	owner_mt(const struct sk_buff skb, struct xt_action_param par)
0265ab44	34	{
f7108a20	35	const struct xt_owner_match_info *info = par->matchinfo;
0265ab44	36	const struct file *filp;
fdd723e2	37	struct sock *sk = skb_to_full_sk(skb);
0265ab44	38
fdd723e2	39	if (sk == NULL \|\| sk->sk_socket == NULL)
0265ab44 JE	40	return (info->match ^ info->invert) == 0;
	41	else if (info->match & info->invert & XT_OWNER_SOCKET)
	42	/*
	43	* Socket exists but user wanted ! --socket-exists.
	44	* (Single ampersands intended.)
	45	*/
	46	return false;
	47
fdd723e2	48	filp = sk->sk_socket->file;
0265ab44 JE	49	if (filp == NULL)
	50	return ((info->match ^ info->invert) &
	51	(XT_OWNER_UID \| XT_OWNER_GID)) == 0;
	52
26711a79 EB	53	if (info->match & XT_OWNER_UID) {
	54	kuid_t uid_min = make_kuid(&init_user_ns, info->uid_min);
	55	kuid_t uid_max = make_kuid(&init_user_ns, info->uid_max);
	56	if ((uid_gte(filp->f_cred->fsuid, uid_min) &&
	57	uid_lte(filp->f_cred->fsuid, uid_max)) ^
edc26f7a	58	!(info->invert & XT_OWNER_UID))
0265ab44	59	return false;
26711a79	60	}
0265ab44	61
26711a79 EB	62	if (info->match & XT_OWNER_GID) {
	63	kgid_t gid_min = make_kgid(&init_user_ns, info->gid_min);
	64	kgid_t gid_max = make_kgid(&init_user_ns, info->gid_max);
	65	if ((gid_gte(filp->f_cred->fsgid, gid_min) &&
	66	gid_lte(filp->f_cred->fsgid, gid_max)) ^
edc26f7a	67	!(info->invert & XT_OWNER_GID))
0265ab44	68	return false;
26711a79	69	}
0265ab44 JE	70
	71	return true;
	72	}
	73
6461caed JE	74	static struct xt_match owner_mt_reg __read_mostly = {
	75	.name = "owner",
	76	.revision = 1,
	77	.family = NFPROTO_UNSPEC,
26711a79	78	.checkentry = owner_check,
6461caed JE	79	.match = owner_mt,
	80	.matchsize = sizeof(struct xt_owner_match_info),
	81	.hooks = (1 << NF_INET_LOCAL_OUT) \|
	82	(1 << NF_INET_POST_ROUTING),
	83	.me = THIS_MODULE,
0265ab44 JE	84	};
	85
	86	static int __init owner_mt_init(void)
	87	{
6461caed	88	return xt_register_match(&owner_mt_reg);
0265ab44 JE	89	}
	90
	91	static void __exit owner_mt_exit(void)
	92	{
6461caed	93	xt_unregister_match(&owner_mt_reg);
0265ab44 JE	94	}
	95
	96	module_init(owner_mt_init);
	97	module_exit(owner_mt_exit);
6461caed	98	MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
2ae15b64	99	MODULE_DESCRIPTION("Xtables: socket owner matching");
0265ab44 JE	100	MODULE_LICENSE("GPL");
	101	MODULE_ALIAS("ipt_owner");
	102	MODULE_ALIAS("ip6t_owner");