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273 lines
5.8 KiB
273 lines
5.8 KiB
/*
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* Network interface table.
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*
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* Network interfaces (devices) do not have a security field, so we
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* maintain a table associating each interface with a SID.
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*
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* Author: James Morris <jmorris@redhat.com>
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*
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* Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2,
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* as published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/stddef.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/notifier.h>
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#include <linux/netdevice.h>
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#include <linux/rcupdate.h>
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#include <net/net_namespace.h>
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#include "security.h"
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#include "objsec.h"
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#include "netif.h"
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#define SEL_NETIF_HASH_SIZE 64
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#define SEL_NETIF_HASH_MAX 1024
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#undef DEBUG
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#ifdef DEBUG
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#define DEBUGP printk
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#else
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#define DEBUGP(format, args...)
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#endif
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struct sel_netif
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{
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struct list_head list;
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struct netif_security_struct nsec;
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struct rcu_head rcu_head;
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};
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static u32 sel_netif_total;
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static LIST_HEAD(sel_netif_list);
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static DEFINE_SPINLOCK(sel_netif_lock);
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static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
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static inline u32 sel_netif_hasfn(struct net_device *dev)
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{
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return (dev->ifindex & (SEL_NETIF_HASH_SIZE - 1));
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}
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/*
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* All of the devices should normally fit in the hash, so we optimize
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* for that case.
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*/
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static inline struct sel_netif *sel_netif_find(struct net_device *dev)
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{
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struct list_head *pos;
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int idx = sel_netif_hasfn(dev);
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__list_for_each_rcu(pos, &sel_netif_hash[idx]) {
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struct sel_netif *netif = list_entry(pos,
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struct sel_netif, list);
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if (likely(netif->nsec.dev == dev))
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return netif;
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}
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return NULL;
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}
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static int sel_netif_insert(struct sel_netif *netif)
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{
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int idx, ret = 0;
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if (sel_netif_total >= SEL_NETIF_HASH_MAX) {
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ret = -ENOSPC;
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goto out;
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}
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idx = sel_netif_hasfn(netif->nsec.dev);
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list_add_rcu(&netif->list, &sel_netif_hash[idx]);
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sel_netif_total++;
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out:
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return ret;
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}
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static void sel_netif_free(struct rcu_head *p)
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{
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struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
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DEBUGP("%s: %s\n", __FUNCTION__, netif->nsec.dev->name);
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kfree(netif);
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}
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static void sel_netif_destroy(struct sel_netif *netif)
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{
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DEBUGP("%s: %s\n", __FUNCTION__, netif->nsec.dev->name);
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list_del_rcu(&netif->list);
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sel_netif_total--;
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call_rcu(&netif->rcu_head, sel_netif_free);
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}
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static struct sel_netif *sel_netif_lookup(struct net_device *dev)
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{
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int ret;
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struct sel_netif *netif, *new;
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struct netif_security_struct *nsec;
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netif = sel_netif_find(dev);
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if (likely(netif != NULL))
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goto out;
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new = kzalloc(sizeof(*new), GFP_ATOMIC);
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if (!new) {
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netif = ERR_PTR(-ENOMEM);
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goto out;
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}
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nsec = &new->nsec;
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ret = security_netif_sid(dev->name, &nsec->if_sid, &nsec->msg_sid);
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if (ret < 0) {
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kfree(new);
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netif = ERR_PTR(ret);
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goto out;
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}
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nsec->dev = dev;
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spin_lock_bh(&sel_netif_lock);
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netif = sel_netif_find(dev);
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if (netif) {
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spin_unlock_bh(&sel_netif_lock);
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kfree(new);
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goto out;
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}
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ret = sel_netif_insert(new);
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spin_unlock_bh(&sel_netif_lock);
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if (ret) {
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kfree(new);
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netif = ERR_PTR(ret);
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goto out;
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}
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netif = new;
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DEBUGP("new: ifindex=%u name=%s if_sid=%u msg_sid=%u\n", dev->ifindex, dev->name,
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nsec->if_sid, nsec->msg_sid);
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out:
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return netif;
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}
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static void sel_netif_assign_sids(u32 if_sid_in, u32 msg_sid_in, u32 *if_sid_out, u32 *msg_sid_out)
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{
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if (if_sid_out)
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*if_sid_out = if_sid_in;
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if (msg_sid_out)
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*msg_sid_out = msg_sid_in;
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}
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static int sel_netif_sids_slow(struct net_device *dev, u32 *if_sid, u32 *msg_sid)
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{
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int ret = 0;
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u32 tmp_if_sid, tmp_msg_sid;
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ret = security_netif_sid(dev->name, &tmp_if_sid, &tmp_msg_sid);
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if (!ret)
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sel_netif_assign_sids(tmp_if_sid, tmp_msg_sid, if_sid, msg_sid);
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return ret;
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}
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int sel_netif_sids(struct net_device *dev, u32 *if_sid, u32 *msg_sid)
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{
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int ret = 0;
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struct sel_netif *netif;
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rcu_read_lock();
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netif = sel_netif_lookup(dev);
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if (IS_ERR(netif)) {
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rcu_read_unlock();
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ret = sel_netif_sids_slow(dev, if_sid, msg_sid);
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goto out;
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}
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sel_netif_assign_sids(netif->nsec.if_sid, netif->nsec.msg_sid, if_sid, msg_sid);
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rcu_read_unlock();
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out:
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return ret;
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}
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static void sel_netif_kill(struct net_device *dev)
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{
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struct sel_netif *netif;
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spin_lock_bh(&sel_netif_lock);
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netif = sel_netif_find(dev);
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if (netif)
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sel_netif_destroy(netif);
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spin_unlock_bh(&sel_netif_lock);
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}
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static void sel_netif_flush(void)
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{
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int idx;
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spin_lock_bh(&sel_netif_lock);
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for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) {
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struct sel_netif *netif;
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list_for_each_entry(netif, &sel_netif_hash[idx], list)
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sel_netif_destroy(netif);
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}
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spin_unlock_bh(&sel_netif_lock);
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}
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static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
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u16 class, u32 perms, u32 *retained)
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{
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if (event == AVC_CALLBACK_RESET) {
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sel_netif_flush();
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synchronize_net();
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}
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return 0;
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}
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static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
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unsigned long event, void *ptr)
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{
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struct net_device *dev = ptr;
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if (dev->nd_net != &init_net)
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return NOTIFY_DONE;
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if (event == NETDEV_DOWN)
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sel_netif_kill(dev);
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return NOTIFY_DONE;
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}
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static struct notifier_block sel_netif_netdev_notifier = {
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.notifier_call = sel_netif_netdev_notifier_handler,
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};
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static __init int sel_netif_init(void)
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{
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int i, err = 0;
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if (!selinux_enabled)
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goto out;
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for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
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INIT_LIST_HEAD(&sel_netif_hash[i]);
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register_netdevice_notifier(&sel_netif_netdev_notifier);
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err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET,
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SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
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if (err)
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panic("avc_add_callback() failed, error %d\n", err);
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out:
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return err;
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}
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__initcall(sel_netif_init);
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