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/*
* Module for modifying the secmark field of the skb, for use by
* security subsystems.
*
* Based on the nfmark match by:
* (C) 1999-2001 Marc Boucher <marc@mbsi.ca>
*
* (C) 2006 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/selinux.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_SECMARK.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Morris <jmorris@redhat.com>");
MODULE_DESCRIPTION("ip[6]tables SECMARK modification module");
MODULE_ALIAS("ipt_SECMARK");
MODULE_ALIAS("ip6t_SECMARK");
#define PFX "SECMARK: "
static u8 mode;
static unsigned int target(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)
{
u32 secmark = 0;
const struct xt_secmark_target_info *info = targinfo;
BUG_ON(info->mode != mode);
switch (mode) {
case SECMARK_MODE_SEL:
secmark = info->u.sel.selsid;
break;
default:
BUG();
}
skb->secmark = secmark;
return XT_CONTINUE;
}
static bool checkentry_selinux(struct xt_secmark_target_info *info)
{
int err;
struct xt_secmark_target_selinux_info *sel = &info->u.sel;
sel->selctx[SECMARK_SELCTX_MAX - 1] = '\0';
err = selinux_string_to_sid(sel->selctx, &sel->selsid);
if (err) {
if (err == -EINVAL)
printk(KERN_INFO PFX "invalid SELinux context \'%s\'\n",
sel->selctx);
return false;
}
if (!sel->selsid) {
printk(KERN_INFO PFX "unable to map SELinux context \'%s\'\n",
sel->selctx);
return false;
}
err = selinux_relabel_packet_permission(sel->selsid);
if (err) {
printk(KERN_INFO PFX "unable to obtain relabeling permission\n");
return false;
}
return true;
}
static bool checkentry(const char *tablename, const void *entry,
const struct xt_target *target, void *targinfo,
unsigned int hook_mask)
{
struct xt_secmark_target_info *info = targinfo;
if (mode && mode != info->mode) {
printk(KERN_INFO PFX "mode already set to %hu cannot mix with "
"rules for mode %hu\n", mode, info->mode);
return false;
}
switch (info->mode) {
case SECMARK_MODE_SEL:
if (!checkentry_selinux(info))
return false;
break;
default:
printk(KERN_INFO PFX "invalid mode: %hu\n", info->mode);
return false;
}
if (!mode)
mode = info->mode;
return true;
}
static struct xt_target xt_secmark_target[] __read_mostly = {
{
.name = "SECMARK",
.family = AF_INET,
.checkentry = checkentry,
.target = target,
.targetsize = sizeof(struct xt_secmark_target_info),
.table = "mangle",
.me = THIS_MODULE,
},
{
.name = "SECMARK",
.family = AF_INET6,
.checkentry = checkentry,
.target = target,
.targetsize = sizeof(struct xt_secmark_target_info),
.table = "mangle",
.me = THIS_MODULE,
},
};
static int __init xt_secmark_init(void)
{
return xt_register_targets(xt_secmark_target,
ARRAY_SIZE(xt_secmark_target));
}
static void __exit xt_secmark_fini(void)
{
xt_unregister_targets(xt_secmark_target, ARRAY_SIZE(xt_secmark_target));
}
module_init(xt_secmark_init);
module_exit(xt_secmark_fini);
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