/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007-2008 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 key operations are protected internally so you can call them at
* any time.
*
* Within mac80211, key references are, just as STA structure references,
* protected by RCU. Note, however, that some things are unprotected,
* namely the key->sta dereferences within the hardware acceleration
* functions. This means that sta_info_destroy() must flush the key todo
* list.
*
* All the direct key list manipulation functions must not sleep because
* they can operate on STA info structs that are protected by RCU.
*/
static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
static const u8 zero_addr[ETH_ALEN];
/* key mutex: used to synchronise todo runners */
static DEFINE_MUTEX(key_mutex);
static DEFINE_SPINLOCK(todo_lock);
static LIST_HEAD(todo_list);
static void key_todo(struct work_struct *work)
{
ieee80211_key_todo();
}
static DECLARE_WORK(todo_work, key_todo);
/**
* add_todo - add todo item for a key
*
* @key: key to add to do item for
* @flag: todo flag(s)
*/
static void add_todo(struct ieee80211_key *key, u32 flag)
{
if (!key)
return;
spin_lock(&todo_lock);
key->flags |= flag;
/*
* Remove again if already on the list so that we move it to the end.
*/
if (!list_empty(&key->todo))
list_del(&key->todo);
list_add_tail(&key->todo, &todo_list);
schedule_work(&todo_work);
spin_unlock(&todo_lock);
}
/**
* ieee80211_key_lock - lock the mac80211 key operation lock
*
* This locks the (global) mac80211 key operation lock, all
* key operations must be done under this lock.
*/
static void ieee80211_key_lock(void)
{
mutex_lock(&key_mutex);
}
/**
* ieee80211_key_unlock - unlock the mac80211 key operation lock
*/
static void ieee80211_key_unlock(void)
{
mutex_unlock(&key_mutex);
}
static void assert_key_lock(void)
{
WARN_ON(!mutex_is_locked(&key_mutex));
}
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 == NL80211_IFTYPE_AP ||
key->sdata->vif.type == NL80211_IFTYPE_AP_VLAN))
addr = zero_addr;
if (key->sta)
addr = key->sta->sta.addr;
return addr;
}
static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
{
const u8 *addr;
int ret;
assert_key_lock();
might_sleep();
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) {
spin_lock(&todo_lock);
key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
spin_unlock(&todo_lock);
}
if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
printk(KERN_ERR "mac80211-%s: failed to set key "
"(%d, %pM) to hardware (%d)\n",
wiphy_name(key->local->hw.wiphy),
key->conf.keyidx, addr, ret);
}
static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
{
const u8 *addr;
int ret;
assert_key_lock();
might_sleep();
if (!key || !key->local->ops->set_key)
return;
spin_lock(&todo_lock);
if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)) {
spin_unlock(&todo_lock);
return;
}
spin_unlock(&todo_lock);
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, %pM) from hardware (%d)\n",
wiphy_name(key->local->hw.wiphy),
key->conf.keyidx, addr, ret);
spin_lock(&todo_lock);
key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
spin_unlock(&todo_lock);
}
static 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];
rcu_assign_pointer(sdata->default_key, key);
if (key)
add_todo(key, KEY_FLAG_TODO_DEFKEY);
}
void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
{
unsigned long flags;
spin_lock_irqsave(&sdata->local->key_lock, flags);
__ieee80211_set_default_key(sdata, idx);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
}
static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
struct ieee80211_key *old,
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 && old && new->conf.keyidx != old->conf.keyidx);
if (old)
idx = old->conf.keyidx;
else
idx = new->conf.keyidx;
defkey = old && sdata->default_key == old;
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 (old) {
/*
* We'll use an empty list to indicate that the key
* has already been removed.
*/
list_del_init(&old->list);
}
}
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;
switch (alg) {
case ALG_WEP:
key->conf.iv_len = WEP_IV_LEN;
key->conf.icv_len = WEP_ICV_LEN;
break;
case ALG_TKIP:
key->conf.iv_len = TKIP_IV_LEN;
key->conf.icv_len = TKIP_ICV_LEN;
break;
case ALG_CCMP:
key->conf.iv_len = CCMP_HDR_LEN;
key->conf.icv_len = CCMP_MIC_LEN;
break;
}
memcpy(key->conf.key, key_data, key_len);
INIT_LIST_HEAD(&key->list);
INIT_LIST_HEAD(&key->todo);
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) {
kfree(key);
return NULL;
}
}
return key;
}
void ieee80211_key_link(struct ieee80211_key *key,
struct ieee80211_sub_if_data *sdata,
struct sta_info *sta)
{
struct ieee80211_key *old_key;
unsigned long flags;
int idx;
BUG_ON(!sdata);
BUG_ON(!key);
idx = key->conf.keyidx;
key->local = sdata->local;
key->sdata = sdata;
key->sta = sta;
if (sta) {
/*
* some hardware cannot handle TKIP with QoS, so
* we indicate whether QoS could be in use.
*/
if (test_sta_flags(sta, WLAN_STA_WME))
key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
/*
* This key is for a specific sta interface,
* inform the driver that it should try to store
* this key as pairwise key.
*/
key->conf.flags |= IEEE80211_KEY_FLAG_PAIRWISE;
} else {
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
struct sta_info *ap;
/*
* We're getting a sta pointer in,
* so must be under 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 (test_sta_flags(ap, WLAN_STA_WME))
key->conf.flags |=
IEEE80211_KEY_FLAG_WMM_STA;
}
}
}
spin_lock_irqsave(&sdata->local->key_lock, flags);
if (sta)
old_key = sta->key;
else
old_key = sdata->keys[idx];
__ieee80211_key_replace(sdata, sta, old_key, key);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
/* free old key later */
add_todo(old_key, KEY_FLAG_TODO_DELETE);
add_todo(key, KEY_FLAG_TODO_ADD_DEBUGFS);
if (netif_running(sdata->dev))
add_todo(key, KEY_FLAG_TODO_HWACCEL_ADD);
}
static void __ieee80211_key_free(struct ieee80211_key *key)
{
/*
* Replace key with nothingness if it was ever used.
*/
if (key->sdata)
__ieee80211_key_replace(key->sdata, key->sta,
key, NULL);
add_todo(key, KEY_FLAG_TODO_DELETE);
}
void ieee80211_key_free(struct ieee80211_key *key)
{
unsigned long flags;
if (!key)
return;
if (!key->sdata) {
/* The key has not been linked yet, simply free it
* and don't Oops */
if (key->conf.alg == ALG_CCMP)
ieee80211_aes_key_free(key->u.ccmp.tfm);
kfree(key);
return;
}
spin_lock_irqsave(&key->sdata->local->key_lock, flags);
__ieee80211_key_free(key);
spin_unlock_irqrestore(&key->sdata->local->key_lock, flags);
}
/*
* To be safe against concurrent manipulations of the list (which shouldn't
* actually happen) we need to hold the spinlock. But under the spinlock we
* can't actually do much, so we defer processing to the todo list. Then run
* the todo list to be sure the operation and possibly previously pending
* operations are completed.
*/
static void ieee80211_todo_for_each_key(struct ieee80211_sub_if_data *sdata,
u32 todo_flags)
{
struct ieee80211_key *key;
unsigned long flags;
might_sleep();
spin_lock_irqsave(&sdata->local->key_lock, flags);
list_for_each_entry(key, &sdata->key_list, list)
add_todo(key, todo_flags);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
ieee80211_key_todo();
}
void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
{
ASSERT_RTNL();
if (WARN_ON(!netif_running(sdata->dev)))
return;
ieee80211_todo_for_each_key(sdata, KEY_FLAG_TODO_HWACCEL_ADD);
}
void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
{
ASSERT_RTNL();
ieee80211_todo_for_each_key(sdata, KEY_FLAG_TODO_HWACCEL_REMOVE);
}
static void __ieee80211_key_destroy(struct ieee80211_key *key)
{
if (!key)
return;
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);
}
static void __ieee80211_key_todo(void)
{
struct ieee80211_key *key;
bool work_done;
u32 todoflags;
/*
* NB: sta_info_destroy relies on this!
*/
synchronize_rcu();
spin_lock(&todo_lock);
while (!list_empty(&todo_list)) {
key = list_first_entry(&todo_list, struct ieee80211_key, todo);
list_del_init(&key->todo);
todoflags = key->flags & (KEY_FLAG_TODO_ADD_DEBUGFS |
KEY_FLAG_TODO_DEFKEY |
KEY_FLAG_TODO_HWACCEL_ADD |
KEY_FLAG_TODO_HWACCEL_REMOVE |
KEY_FLAG_TODO_DELETE);
key->flags &= ~todoflags;
spin_unlock(&todo_lock);
work_done = false;
if (todoflags & KEY_FLAG_TODO_ADD_DEBUGFS) {
ieee80211_debugfs_key_add(key);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_DEFKEY) {
ieee80211_debugfs_key_remove_default(key->sdata);
ieee80211_debugfs_key_add_default(key->sdata);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_HWACCEL_ADD) {
ieee80211_key_enable_hw_accel(key);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_HWACCEL_REMOVE) {
ieee80211_key_disable_hw_accel(key);
work_done = true;
}
if (todoflags & KEY_FLAG_TODO_DELETE) {
__ieee80211_key_destroy(key);
work_done = true;
}
WARN_ON(!work_done);
spin_lock(&todo_lock);
}
spin_unlock(&todo_lock);
}
void ieee80211_key_todo(void)
{
ieee80211_key_lock();
__ieee80211_key_todo();
ieee80211_key_unlock();
}
void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key, *tmp;
unsigned long flags;
ieee80211_key_lock();
ieee80211_debugfs_key_remove_default(sdata);
spin_lock_irqsave(&sdata->local->key_lock, flags);
list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
__ieee80211_key_free(key);
spin_unlock_irqrestore(&sdata->local->key_lock, flags);
__ieee80211_key_todo();
ieee80211_key_unlock();
}
