net/mac80211/key.c - linux - Git at Google

 /*
  * Copyright 2002-2005, Instant802 Networks, Inc.
  * Copyright 2005-2006, Devicescape Software, Inc.
  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
  * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>
  *
  * 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/if_ether.h>
 #include <linux/etherdevice.h>
 #include <linux/list.h>
 #include <linux/rcupdate.h>
 #include <linux/rtnetlink.h>
 #include <net/mac80211.h>
 #include "ieee80211_i.h"
 #include "debugfs_key.h"
 #include "aes_ccm.h"


 /**
  * DOC: Key handling basics
  *
  * Key handling in mac80211 is done based on per-interface (sub_if_data)
  * keys and per-station keys. Since each station belongs to an interface,
  * each station key also belongs to that interface.
  *
  * Hardware acceleration is done on a best-effort basis, for each key
  * that is eligible the hardware is asked to enable that key but if
  * it cannot do that they key is simply kept for software encryption.
  * There is currently no way of knowing this except by looking into
  * debugfs.
  *
  * All operations here are called under RTNL so no extra locking is
  * required.
  *
  * NOTE: This code requires that sta info *destruction* is done under
  *	 RTNL, otherwise it can try to access already freed STA structs
  *	 when a STA key is being freed.
  */

 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
 static const u8 zero_addr[ETH_ALEN];

 static const u8 *get_mac_for_key(struct ieee80211_key *key)
 {
 	const u8 *addr = bcast_addr;

 	/*
 	 * If we're an AP we won't ever receive frames with a non-WEP
 	 * group key so we tell the driver that by using the zero MAC
 	 * address to indicate a transmit-only key.
 	 */
 	if (key->conf.alg != ALG_WEP &&
 	    (key->sdata->vif.type == IEEE80211_IF_TYPE_AP ||
 	     key->sdata->vif.type == IEEE80211_IF_TYPE_VLAN))
 		addr = zero_addr;

 	if (key->sta)
 		addr = key->sta->addr;

 	return addr;
 }

 static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 {
 	const u8 *addr;
 	int ret;
 	DECLARE_MAC_BUF(mac);

 	if (!key->local->ops->set_key)
 		return;

 	addr = get_mac_for_key(key);

 	ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
 				       key->sdata->dev->dev_addr, addr,
 				       &key->conf);

 	if (!ret)
 		key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;

 	if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
 		printk(KERN_ERR "mac80211-%s: failed to set key "
 		       "(%d, %s) to hardware (%d)\n",
 		       wiphy_name(key->local->hw.wiphy),
 		       key->conf.keyidx, print_mac(mac, addr), ret);
 }

 static void ieee80211_key_mark_hw_accel_off(struct ieee80211_key *key)
 {
 	if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
 		key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
 		key->flags |= KEY_FLAG_REMOVE_FROM_HARDWARE;
 	}
 }

 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
 {
 	const u8 *addr;
 	int ret;
 	DECLARE_MAC_BUF(mac);

 	if (!key || !key->local->ops->set_key)
 		return;

 	if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 	    !(key->flags & KEY_FLAG_REMOVE_FROM_HARDWARE))
 		return;

 	addr = get_mac_for_key(key);

 	ret = key->local->ops->set_key(local_to_hw(key->local), DISABLE_KEY,
 				       key->sdata->dev->dev_addr, addr,
 				       &key->conf);

 	if (ret)
 		printk(KERN_ERR "mac80211-%s: failed to remove key "
 		       "(%d, %s) from hardware (%d)\n",
 		       wiphy_name(key->local->hw.wiphy),
 		       key->conf.keyidx, print_mac(mac, addr), ret);

 	key->flags &= ~(KEY_FLAG_UPLOADED_TO_HARDWARE |
 			KEY_FLAG_REMOVE_FROM_HARDWARE);
 }

 struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
 					  int idx,
 					  size_t key_len,
 					  const u8 *key_data)
 {
 	struct ieee80211_key *key;

 	BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS);

 	key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
 	if (!key)
 		return NULL;

 	/*
 	 * Default to software encryption; we'll later upload the
 	 * key to the hardware if possible.
 	 */
 	key->conf.flags = 0;
 	key->flags = 0;

 	key->conf.alg = alg;
 	key->conf.keyidx = idx;
 	key->conf.keylen = key_len;
 	memcpy(key->conf.key, key_data, key_len);
 	INIT_LIST_HEAD(&key->list);

 	if (alg == ALG_CCMP) {
 		/*
 		 * Initialize AES key state here as an optimization so that
 		 * it does not need to be initialized for every packet.
 		 */
 		key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
 		if (!key->u.ccmp.tfm) {
 			ieee80211_key_free(key);
 			return NULL;
 		}
 	}

 	return key;
 }

 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
 				    struct sta_info *sta,
 				    struct ieee80211_key *key,
 				    struct ieee80211_key *new)
 {
 	int idx, defkey;

 	if (new)
 		list_add(&new->list, &sdata->key_list);

 	if (sta) {
 		rcu_assign_pointer(sta->key, new);
 	} else {
 		WARN_ON(new && key && new->conf.keyidx != key->conf.keyidx);

 		if (key)
 			idx = key->conf.keyidx;
 		else
 			idx = new->conf.keyidx;

 		defkey = key && sdata->default_key == key;

 		if (defkey && !new)
 			ieee80211_set_default_key(sdata, -1);

 		rcu_assign_pointer(sdata->keys[idx], new);
 		if (defkey && new)
 			ieee80211_set_default_key(sdata, new->conf.keyidx);
 	}

 	if (key) {
 		ieee80211_key_mark_hw_accel_off(key);
 		/*
 		 * We'll use an empty list to indicate that the key
 		 * has already been removed.
 		 */
 		list_del_init(&key->list);
 	}
 }

 void ieee80211_key_link(struct ieee80211_key *key,
 			struct ieee80211_sub_if_data *sdata,
 			struct sta_info *sta)
 {
 	struct ieee80211_key *old_key;
 	int idx;

 	ASSERT_RTNL();
 	might_sleep();

 	BUG_ON(!sdata);
 	BUG_ON(!key);

 	idx = key->conf.keyidx;
 	key->local = sdata->local;
 	key->sdata = sdata;
 	key->sta = sta;

 	ieee80211_debugfs_key_add(key->local, key);

 	if (sta) {
 		ieee80211_debugfs_key_sta_link(key, sta);

 		/*
 		 * some hardware cannot handle TKIP with QoS, so
 		 * we indicate whether QoS could be in use.
 		 */
 		if (sta->flags & WLAN_STA_WME)
 			key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
 	} else {
 		if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
 			struct sta_info *ap;

 			rcu_read_lock();

 			/* same here, the AP could be using QoS */
 			ap = sta_info_get(key->local, key->sdata->u.sta.bssid);
 			if (ap) {
 				if (ap->flags & WLAN_STA_WME)
 					key->conf.flags |=
 						IEEE80211_KEY_FLAG_WMM_STA;
 			}

 			rcu_read_unlock();
 		}
 	}

 	if (sta)
 		old_key = sta->key;
 	else
 		old_key = sdata->keys[idx];

 	__ieee80211_key_replace(sdata, sta, old_key, key);

 	if (old_key) {
 		synchronize_rcu();
 		ieee80211_key_free(old_key);
 	}

 	if (netif_running(sdata->dev))
 		ieee80211_key_enable_hw_accel(key);
 }

 void ieee80211_key_free(struct ieee80211_key *key)
 {
 	ASSERT_RTNL();
 	might_sleep();

 	if (!key)
 		return;

 	if (key->sdata) {
 		/*
 		 * Replace key with nothingness.
 		 *
 		 * Because other code may have key reference (RCU protected)
 		 * right now, we then wait for a grace period before freeing
 		 * it.
 		 * An empty list indicates it was never added to the key list
 		 * or has been removed already. It may, however, still be in
 		 * hardware for acceleration.
 		 */
 		if (!list_empty(&key->list))
 			__ieee80211_key_replace(key->sdata, key->sta,
 						key, NULL);

 		/*
 		 * Do NOT remove this without looking at sta_info_destroy()
 		 */
 		synchronize_rcu();

 		/*
 		 * Remove from hwaccel if appropriate, this will
 		 * only happen when the key is actually unlinked,
 		 * it will already be done when the key was replaced.
 		 */
 		ieee80211_key_disable_hw_accel(key);
 	}

 	if (key->conf.alg == ALG_CCMP)
 		ieee80211_aes_key_free(key->u.ccmp.tfm);
 	ieee80211_debugfs_key_remove(key);

 	kfree(key);
 }

 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
 {
 	struct ieee80211_key *key = NULL;

 	if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
 		key = sdata->keys[idx];

 	if (sdata->default_key != key) {
 		ieee80211_debugfs_key_remove_default(sdata);

 		rcu_assign_pointer(sdata->default_key, key);

 		if (sdata->default_key)
 			ieee80211_debugfs_key_add_default(sdata);
 	}
 }

 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
 {
 	struct ieee80211_key *key, *tmp;
 	LIST_HEAD(tmp_list);

 	ASSERT_RTNL();
 	might_sleep();

 	list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
 		ieee80211_key_free(key);
 }

 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
 {
 	struct ieee80211_key *key;

 	ASSERT_RTNL();
 	might_sleep();

 	if (WARN_ON(!netif_running(sdata->dev)))
 		return;

 	list_for_each_entry(key, &sdata->key_list, list)
 		ieee80211_key_enable_hw_accel(key);
 }

 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
 {
 	struct ieee80211_key *key;

 	ASSERT_RTNL();
 	might_sleep();

 	list_for_each_entry(key, &sdata->key_list, list)
 		ieee80211_key_disable_hw_accel(key);
 }
	/*
	* Copyright 2002-2005, Instant802 Networks, Inc.
	* Copyright 2005-2006, Devicescape Software, Inc.
	* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
	* Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
	*
	* 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/if_ether.h>
	#include <linux/etherdevice.h>
	#include <linux/list.h>
	#include <linux/rcupdate.h>
	#include <linux/rtnetlink.h>
	#include <net/mac80211.h>
	#include "ieee80211_i.h"
	#include "debugfs_key.h"
	#include "aes_ccm.h"


	/**
	* DOC: Key handling basics
	*
	* Key handling in mac80211 is done based on per-interface (sub_if_data)
	* keys and per-station keys. Since each station belongs to an interface,
	* each station key also belongs to that interface.
	*
	* Hardware acceleration is done on a best-effort basis, for each key
	* that is eligible the hardware is asked to enable that key but if
	* it cannot do that they key is simply kept for software encryption.
	* There is currently no way of knowing this except by looking into
	* debugfs.
	*
	* All operations here are called under RTNL so no extra locking is
	* required.
	*
	* NOTE: This code requires that sta info destruction is done under
	* RTNL, otherwise it can try to access already freed STA structs
	* when a STA key is being freed.
	*/

	static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
	static const u8 zero_addr[ETH_ALEN];

	static const u8 get_mac_for_key(struct ieee80211_key key)
	{
	const u8 *addr = bcast_addr;

	/*
	* If we're an AP we won't ever receive frames with a non-WEP
	* group key so we tell the driver that by using the zero MAC
	* address to indicate a transmit-only key.
	*/
	if (key->conf.alg != ALG_WEP &&
	(key->sdata->vif.type == IEEE80211_IF_TYPE_AP \|\|
	key->sdata->vif.type == IEEE80211_IF_TYPE_VLAN))
	addr = zero_addr;

	if (key->sta)
	addr = key->sta->addr;

	return addr;
	}

	static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
	{
	const u8 *addr;
	int ret;
	DECLARE_MAC_BUF(mac);

	if (!key->local->ops->set_key)
	return;

	addr = get_mac_for_key(key);

	ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
	key->sdata->dev->dev_addr, addr,
	&key->conf);

	if (!ret)
	key->flags \|= KEY_FLAG_UPLOADED_TO_HARDWARE;

	if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
	printk(KERN_ERR "mac80211-%s: failed to set key "
	"(%d, %s) to hardware (%d)\n",
	wiphy_name(key->local->hw.wiphy),
	key->conf.keyidx, print_mac(mac, addr), ret);
	}

	static void ieee80211_key_mark_hw_accel_off(struct ieee80211_key *key)
	{
	if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
	key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
	key->flags \|= KEY_FLAG_REMOVE_FROM_HARDWARE;
	}
	}

	static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
	{
	const u8 *addr;
	int ret;
	DECLARE_MAC_BUF(mac);

	if (!key \|\| !key->local->ops->set_key)
	return;

	if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
	!(key->flags & KEY_FLAG_REMOVE_FROM_HARDWARE))
	return;

	addr = get_mac_for_key(key);

	ret = key->local->ops->set_key(local_to_hw(key->local), DISABLE_KEY,
	key->sdata->dev->dev_addr, addr,
	&key->conf);

	if (ret)
	printk(KERN_ERR "mac80211-%s: failed to remove key "
	"(%d, %s) from hardware (%d)\n",
	wiphy_name(key->local->hw.wiphy),
	key->conf.keyidx, print_mac(mac, addr), ret);

	key->flags &= ~(KEY_FLAG_UPLOADED_TO_HARDWARE \|
	KEY_FLAG_REMOVE_FROM_HARDWARE);
	}

	struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
	int idx,
	size_t key_len,
	const u8 *key_data)
	{
	struct ieee80211_key *key;

	BUG_ON(idx < 0 \|\| idx >= NUM_DEFAULT_KEYS);

	key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
	if (!key)
	return NULL;

	/*
	* Default to software encryption; we'll later upload the
	* key to the hardware if possible.
	*/
	key->conf.flags = 0;
	key->flags = 0;

	key->conf.alg = alg;
	key->conf.keyidx = idx;
	key->conf.keylen = key_len;
	memcpy(key->conf.key, key_data, key_len);
	INIT_LIST_HEAD(&key->list);

	if (alg == ALG_CCMP) {
	/*
	* Initialize AES key state here as an optimization so that
	* it does not need to be initialized for every packet.
	*/
	key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
	if (!key->u.ccmp.tfm) {
	ieee80211_key_free(key);
	return NULL;
	}
	}

	return key;
	}

	static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
	struct sta_info *sta,
	struct ieee80211_key *key,
	struct ieee80211_key *new)
	{
	int idx, defkey;

	if (new)
	list_add(&new->list, &sdata->key_list);

	if (sta) {
	rcu_assign_pointer(sta->key, new);
	} else {
	WARN_ON(new && key && new->conf.keyidx != key->conf.keyidx);

	if (key)
	idx = key->conf.keyidx;
	else
	idx = new->conf.keyidx;

	defkey = key && sdata->default_key == key;

	if (defkey && !new)
	ieee80211_set_default_key(sdata, -1);

	rcu_assign_pointer(sdata->keys[idx], new);
	if (defkey && new)
	ieee80211_set_default_key(sdata, new->conf.keyidx);
	}

	if (key) {
	ieee80211_key_mark_hw_accel_off(key);
	/*
	* We'll use an empty list to indicate that the key
	* has already been removed.
	*/
	list_del_init(&key->list);
	}
	}

	void ieee80211_key_link(struct ieee80211_key *key,
	struct ieee80211_sub_if_data *sdata,
	struct sta_info *sta)
	{
	struct ieee80211_key *old_key;
	int idx;

	ASSERT_RTNL();
	might_sleep();

	BUG_ON(!sdata);
	BUG_ON(!key);

	idx = key->conf.keyidx;
	key->local = sdata->local;
	key->sdata = sdata;
	key->sta = sta;

	ieee80211_debugfs_key_add(key->local, key);

	if (sta) {
	ieee80211_debugfs_key_sta_link(key, sta);

	/*
	* some hardware cannot handle TKIP with QoS, so
	* we indicate whether QoS could be in use.
	*/
	if (sta->flags & WLAN_STA_WME)
	key->conf.flags \|= IEEE80211_KEY_FLAG_WMM_STA;
	} else {
	if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
	struct sta_info *ap;

	rcu_read_lock();

	/* same here, the AP could be using QoS */
	ap = sta_info_get(key->local, key->sdata->u.sta.bssid);
	if (ap) {
	if (ap->flags & WLAN_STA_WME)
	key->conf.flags \|=
	IEEE80211_KEY_FLAG_WMM_STA;
	}

	rcu_read_unlock();
	}
	}

	if (sta)
	old_key = sta->key;
	else
	old_key = sdata->keys[idx];

	__ieee80211_key_replace(sdata, sta, old_key, key);

	if (old_key) {
	synchronize_rcu();
	ieee80211_key_free(old_key);
	}

	if (netif_running(sdata->dev))
	ieee80211_key_enable_hw_accel(key);
	}

	void ieee80211_key_free(struct ieee80211_key *key)
	{
	ASSERT_RTNL();
	might_sleep();

	if (!key)
	return;

	if (key->sdata) {
	/*
	* Replace key with nothingness.
	*
	* Because other code may have key reference (RCU protected)
	* right now, we then wait for a grace period before freeing
	* it.
	* An empty list indicates it was never added to the key list
	* or has been removed already. It may, however, still be in
	* hardware for acceleration.
	*/
	if (!list_empty(&key->list))
	__ieee80211_key_replace(key->sdata, key->sta,
	key, NULL);

	/*
	* Do NOT remove this without looking at sta_info_destroy()
	*/
	synchronize_rcu();

	/*
	* Remove from hwaccel if appropriate, this will
	* only happen when the key is actually unlinked,
	* it will already be done when the key was replaced.
	*/
	ieee80211_key_disable_hw_accel(key);
	}

	if (key->conf.alg == ALG_CCMP)
	ieee80211_aes_key_free(key->u.ccmp.tfm);
	ieee80211_debugfs_key_remove(key);

	kfree(key);
	}

	void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
	{
	struct ieee80211_key *key = NULL;

	if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
	key = sdata->keys[idx];

	if (sdata->default_key != key) {
	ieee80211_debugfs_key_remove_default(sdata);

	rcu_assign_pointer(sdata->default_key, key);

	if (sdata->default_key)
	ieee80211_debugfs_key_add_default(sdata);
	}
	}

	void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
	{
	struct ieee80211_key key, tmp;
	LIST_HEAD(tmp_list);

	ASSERT_RTNL();
	might_sleep();

	list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
	ieee80211_key_free(key);
	}

	void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
	{
	struct ieee80211_key *key;

	ASSERT_RTNL();
	might_sleep();

	if (WARN_ON(!netif_running(sdata->dev)))
	return;

	list_for_each_entry(key, &sdata->key_list, list)
	ieee80211_key_enable_hw_accel(key);
	}

	void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
	{
	struct ieee80211_key *key;

	ASSERT_RTNL();
	might_sleep();

	list_for_each_entry(key, &sdata->key_list, list)
	ieee80211_key_disable_hw_accel(key);
	}