[mirror_ubuntu-artful-kernel.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 <linux/cred.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;
	struct net *net = par->net;

	/* Only allow the common case where the userns of the writer
	 * matches the userns of the network namespace.
	 */
	if ((info->match & (XT_OWNER_UID|XT_OWNER_GID)) &&
	    (current_user_ns() != net->user_ns))
		return -EINVAL;

	/* Ensure the uids are valid */
	if (info->match & XT_OWNER_UID) {
		kuid_t uid_min = make_kuid(net->user_ns, info->uid_min);
		kuid_t uid_max = make_kuid(net->user_ns, info->uid_max);

		if (!uid_valid(uid_min) || !uid_valid(uid_max) ||
		    (info->uid_max < info->uid_min) ||
		    uid_lt(uid_max, uid_min)) {
			return -EINVAL;
		}
	}

	/* Ensure the gids are valid */
	if (info->match & XT_OWNER_GID) {
		kgid_t gid_min = make_kgid(net->user_ns, info->gid_min);
		kgid_t gid_max = make_kgid(net->user_ns, info->gid_max);

		if (!gid_valid(gid_min) || !gid_valid(gid_max) ||
		    (info->gid_max < info->gid_min) ||
		    gid_lt(gid_max, gid_min)) {
			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);
	struct net *net = xt_net(par);

	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(net->user_ns, info->uid_min);
		kuid_t uid_max = make_kuid(net->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(net->user_ns, info->gid_min);
		kgid_t gid_max = make_kgid(net->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>
5b825c3a IM	16	#include <linux/cred.h>
5b825c3a IM	17
0265ab44	18	#include <net/sock.h>
fdd723e2	19	#include <net/inet_sock.h>
0265ab44 JE	20	#include <linux/netfilter/x_tables.h>
0265ab44 JE	21	#include <linux/netfilter/xt_owner.h>
0265ab44	22
26711a79 EB	23	static int owner_check(const struct xt_mtchk_param *par)
	24	{
	25	struct xt_owner_match_info *info = par->matchinfo;
9847371a	26	struct net *net = par->net;
26711a79	27
9847371a EB	28	/* Only allow the common case where the userns of the writer
	29	* matches the userns of the network namespace.
	30	*/
26711a79	31	if ((info->match & (XT_OWNER_UID\|XT_OWNER_GID)) &&
9847371a	32	(current_user_ns() != net->user_ns))
26711a79	33	return -EINVAL;
9847371a EB	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
26711a79 EB	59	return 0;
	60	}
	61
0265ab44	62	static bool
62fc8051	63	owner_mt(const struct sk_buff skb, struct xt_action_param par)
0265ab44	64	{
f7108a20	65	const struct xt_owner_match_info *info = par->matchinfo;
0265ab44	66	const struct file *filp;
fdd723e2	67	struct sock *sk = skb_to_full_sk(skb);
613dbd95	68	struct net *net = xt_net(par);
0265ab44	69
fdd723e2	70	if (sk == NULL \|\| sk->sk_socket == NULL)
0265ab44 JE	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
fdd723e2	79	filp = sk->sk_socket->file;
0265ab44 JE	80	if (filp == NULL)
	81	return ((info->match ^ info->invert) &
	82	(XT_OWNER_UID \| XT_OWNER_GID)) == 0;
	83
26711a79	84	if (info->match & XT_OWNER_UID) {
9847371a EB	85	kuid_t uid_min = make_kuid(net->user_ns, info->uid_min);
9847371a EB	86	kuid_t uid_max = make_kuid(net->user_ns, info->uid_max);
26711a79 EB	87	if ((uid_gte(filp->f_cred->fsuid, uid_min) &&
26711a79 EB	88	uid_lte(filp->f_cred->fsuid, uid_max)) ^
edc26f7a	89	!(info->invert & XT_OWNER_UID))
0265ab44	90	return false;
26711a79	91	}
0265ab44	92
26711a79	93	if (info->match & XT_OWNER_GID) {
9847371a EB	94	kgid_t gid_min = make_kgid(net->user_ns, info->gid_min);
9847371a EB	95	kgid_t gid_max = make_kgid(net->user_ns, info->gid_max);
26711a79 EB	96	if ((gid_gte(filp->f_cred->fsgid, gid_min) &&
26711a79 EB	97	gid_lte(filp->f_cred->fsgid, gid_max)) ^
edc26f7a	98	!(info->invert & XT_OWNER_GID))
0265ab44	99	return false;
26711a79	100	}
0265ab44 JE	101
	102	return true;
	103	}
	104
6461caed JE	105	static struct xt_match owner_mt_reg __read_mostly = {
	106	.name = "owner",
	107	.revision = 1,
	108	.family = NFPROTO_UNSPEC,
26711a79	109	.checkentry = owner_check,
6461caed JE	110	.match = owner_mt,
	111	.matchsize = sizeof(struct xt_owner_match_info),
	112	.hooks = (1 << NF_INET_LOCAL_OUT) \|
	113	(1 << NF_INET_POST_ROUTING),
	114	.me = THIS_MODULE,
0265ab44 JE	115	};
	116
	117	static int __init owner_mt_init(void)
	118	{
6461caed	119	return xt_register_match(&owner_mt_reg);
0265ab44 JE	120	}
	121
	122	static void __exit owner_mt_exit(void)
	123	{
6461caed	124	xt_unregister_match(&owner_mt_reg);
0265ab44 JE	125	}
	126
	127	module_init(owner_mt_init);
	128	module_exit(owner_mt_exit);
6461caed	129	MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
2ae15b64	130	MODULE_DESCRIPTION("Xtables: socket owner matching");
0265ab44 JE	131	MODULE_LICENSE("GPL");
	132	MODULE_ALIAS("ipt_owner");
	133	MODULE_ALIAS("ip6t_owner");