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/*
* This module is used to copy security markings from packets
* to connections, and restore security markings from connections
* back to packets. This would normally be performed in conjunction
* with the SECMARK target and state match.
*
* Based somewhat on CONNMARK:
* Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
* by Henrik Nordstrom <hno@marasystems.com>
*
* (C) 2006,2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
*
* 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/netfilter/x_tables.h>
#include <linux/netfilter/xt_CONNSECMARK.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#define PFX "CONNSECMARK: "
MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
MODULE_DESCRIPTION("Xtables: target for copying between connection and security mark");
MODULE_ALIAS("ipt_CONNSECMARK");
MODULE_ALIAS("ip6t_CONNSECMARK");
/*
* If the packet has a security mark and the connection does not, copy
* the security mark from the packet to the connection.
*/
static void secmark_save(const struct sk_buff *skb)
{
if (skb->secmark) {
struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
ct = nf_ct_get(skb, &ctinfo);
if (ct && !ct->secmark) {
ct->secmark = skb->secmark;
nf_conntrack_event_cache(IPCT_SECMARK, skb);
}
}
}
/*
* If packet has no security mark, and the connection does, restore the
* security mark from the connection to the packet.
*/
static void secmark_restore(struct sk_buff *skb)
{
if (!skb->secmark) {
const struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
ct = nf_ct_get(skb, &ctinfo);
if (ct && ct->secmark)
skb->secmark = ct->secmark;
}
}
static unsigned int
connsecmark_tg(struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, unsigned int hooknum,
const struct xt_target *target, const void *targinfo)
{
const struct xt_connsecmark_target_info *info = targinfo;
switch (info->mode) {
case CONNSECMARK_SAVE:
secmark_save(skb);
break;
case CONNSECMARK_RESTORE:
secmark_restore(skb);
break;
default:
BUG();
}
return XT_CONTINUE;
}
static bool
connsecmark_tg_check(const char *tablename, const void *entry,
const struct xt_target *target, void *targinfo,
unsigned int hook_mask)
{
const struct xt_connsecmark_target_info *info = targinfo;
if (strcmp(tablename, "mangle") && strcmp(tablename, "security")) {
printk(KERN_INFO PFX "target only valid in the \'mangle\' "
"or \'security\' tables, not \'%s\'.\n", tablename);
return false;
}
switch (info->mode) {
case CONNSECMARK_SAVE:
case CONNSECMARK_RESTORE:
break;
default:
printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode);
return false;
}
if (nf_ct_l3proto_try_module_get(target->family) < 0) {
printk(KERN_WARNING "can't load conntrack support for "
"proto=%u\n", target->family);
return false;
}
return true;
}
static void
connsecmark_tg_destroy(const struct xt_target *target, void *targinfo)
{
nf_ct_l3proto_module_put(target->family);
}
static struct xt_target connsecmark_tg_reg[] __read_mostly = {
{
.name = "CONNSECMARK",
.family = AF_INET,
.checkentry = connsecmark_tg_check,
.destroy = connsecmark_tg_destroy,
.target = connsecmark_tg,
.targetsize = sizeof(struct xt_connsecmark_target_info),
.me = THIS_MODULE,
},
{
.name = "CONNSECMARK",
.family = AF_INET6,
.checkentry = connsecmark_tg_check,
.destroy = connsecmark_tg_destroy,
.target = connsecmark_tg,
.targetsize = sizeof(struct xt_connsecmark_target_info),
.me = THIS_MODULE,
},
};
static int __init connsecmark_tg_init(void)
{
return xt_register_targets(connsecmark_tg_reg,
ARRAY_SIZE(connsecmark_tg_reg));
}
static void __exit connsecmark_tg_exit(void)
{
xt_unregister_targets(connsecmark_tg_reg,
ARRAY_SIZE(connsecmark_tg_reg));
}
module_init(connsecmark_tg_init);
module_exit(connsecmark_tg_exit);
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