/*
* 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);
}
