/*
* Network interface table.
*
* Network interfaces (devices) do not have a security field, so we
* maintain a table associating each interface with a SID.
*
* Author: James Morris <jmorris@redhat.com>
*
* Copyright (C) 2003 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/init.h>
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/rcupdate.h>
#include <net/net_namespace.h>
#include "security.h"
#include "objsec.h"
#include "netif.h"
#define SEL_NETIF_HASH_SIZE 64
#define SEL_NETIF_HASH_MAX 1024
#undef DEBUG
#ifdef DEBUG
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif
struct sel_netif
{
struct list_head list;
struct netif_security_struct nsec;
struct rcu_head rcu_head;
};
static u32 sel_netif_total;
static LIST_HEAD(sel_netif_list);
static DEFINE_SPINLOCK(sel_netif_lock);
static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
static inline u32 sel_netif_hasfn(struct net_device *dev)
{
return (dev->ifindex & (SEL_NETIF_HASH_SIZE - 1));
}
/*
* All of the devices should normally fit in the hash, so we optimize
* for that case.
*/
static inline struct sel_netif *sel_netif_find(struct net_device *dev)
{
struct list_head *pos;
int idx = sel_netif_hasfn(dev);
__list_for_each_rcu(pos, &sel_netif_hash[idx]) {
struct sel_netif *netif = list_entry(pos,
struct sel_netif, list);
if (likely(netif->nsec.dev == dev))
return netif;
}
return NULL;
}
static int sel_netif_insert(struct sel_netif *netif)
{
int idx, ret = 0;
if (sel_netif_total >= SEL_NETIF_HASH_MAX) {
ret = -ENOSPC;
goto out;
}
idx = sel_netif_hasfn(netif->nsec.dev);
list_add_rcu(&netif->list, &sel_netif_hash[idx]);
sel_netif_total++;
out:
return ret;
}
static void sel_netif_free(struct rcu_head *p)
{
struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
DEBUGP("%s: %s\n", __FUNCTION__, netif->nsec.dev->name);
kfree(netif);
}
static void sel_netif_destroy(struct sel_netif *netif)
{
DEBUGP("%s: %s\n", __FUNCTION__, netif->nsec.dev->name);
list_del_rcu(&netif->list);
sel_netif_total--;
call_rcu(&netif->rcu_head, sel_netif_free);
}
static struct sel_netif *sel_netif_lookup(struct net_device *dev)
{
int ret;
struct sel_netif *netif, *new;
struct netif_security_struct *nsec;
netif = sel_netif_find(dev);
if (likely(netif != NULL))
goto out;
new = kzalloc(sizeof(*new), GFP_ATOMIC);
if (!new) {
netif = ERR_PTR(-ENOMEM);
goto out;
}
nsec = &new->nsec;
ret = security_netif_sid(dev->name, &nsec->if_sid, &nsec->msg_sid);
if (ret < 0) {
kfree(new);
netif = ERR_PTR(ret);
goto out;
}
nsec->dev = dev;
spin_lock_bh(&sel_netif_lock);
netif = sel_netif_find(dev);
if (netif) {
spin_unlock_bh(&sel_netif_lock);
kfree(new);
goto out;
}
ret = sel_netif_insert(new);
spin_unlock_bh(&sel_netif_lock);
if (ret) {
kfree(new);
netif = ERR_PTR(ret);
goto out;
}
netif = new;
DEBUGP("new: ifindex=%u name=%s if_sid=%u msg_sid=%u\n", dev->ifindex, dev->name,
nsec->if_sid, nsec->msg_sid);
out:
return netif;
}
static void sel_netif_assign_sids(u32 if_sid_in, u32 msg_sid_in, u32 *if_sid_out, u32 *msg_sid_out)
{
if (if_sid_out)
*if_sid_out = if_sid_in;
if (msg_sid_out)
*msg_sid_out = msg_sid_in;
}
static int sel_netif_sids_slow(struct net_device *dev, u32 *if_sid, u32 *msg_sid)
{
int ret = 0;
u32 tmp_if_sid, tmp_msg_sid;
ret = security_netif_sid(dev->name, &tmp_if_sid, &tmp_msg_sid);
if (!ret)
sel_netif_assign_sids(tmp_if_sid, tmp_msg_sid, if_sid, msg_sid);
return ret;
}
int sel_netif_sids(struct net_device *dev, u32 *if_sid, u32 *msg_sid)
{
int ret = 0;
struct sel_netif *netif;
rcu_read_lock();
netif = sel_netif_lookup(dev);
if (IS_ERR(netif)) {
rcu_read_unlock();
ret = sel_netif_sids_slow(dev, if_sid, msg_sid);
goto out;
}
sel_netif_assign_sids(netif->nsec.if_sid, netif->nsec.msg_sid, if_sid, msg_sid);
rcu_read_unlock();
out:
return ret;
}
static void sel_netif_kill(struct net_device *dev)
{
struct sel_netif *netif;
spin_lock_bh(&sel_netif_lock);
netif = sel_netif_find(dev);
if (netif)
sel_netif_destroy(netif);
spin_unlock_bh(&sel_netif_lock);
}
static void sel_netif_flush(void)
{
int idx;
spin_lock_bh(&sel_netif_lock);
for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) {
struct sel_netif *netif;
list_for_each_entry(netif, &sel_netif_hash[idx], list)
sel_netif_destroy(netif);
}
spin_unlock_bh(&sel_netif_lock);
}
static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
u16 class, u32 perms, u32 *retained)
{
if (event == AVC_CALLBACK_RESET) {
sel_netif_flush();
synchronize_net();
}
return 0;
}
static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
if (dev->nd_net != &init_net)
return NOTIFY_DONE;
if (event == NETDEV_DOWN)
sel_netif_kill(dev);
return NOTIFY_DONE;
}
static struct notifier_block sel_netif_netdev_notifier = {
.notifier_call = sel_netif_netdev_notifier_handler,
};
static __init int sel_netif_init(void)
{
int i, err = 0;
if (!selinux_enabled)
goto out;
for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
INIT_LIST_HEAD(&sel_netif_hash[i]);
register_netdevice_notifier(&sel_netif_netdev_notifier);
err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET,
SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
if (err)
panic("avc_add_callback() failed, error %d\n", err);
out:
return err;
}
__initcall(sel_netif_init);
