linux/security/selinux/netif.c
Eric W. Biederman e9dc865340 [NET]: Make device event notification network namespace safe
Every user of the network device notifiers is either a protocol
stack or a pseudo device.  If a protocol stack that does not have
support for multiple network namespaces receives an event for a
device that is not in the initial network namespace it quite possibly
can get confused and do the wrong thing.

To avoid problems until all of the protocol stacks are converted
this patch modifies all netdev event handlers to ignore events on
devices that are not in the initial network namespace.

As the rest of the code is made network namespace aware these
checks can be removed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:49:09 -07:00

273 lines
5.8 KiB
C

/*
* 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);