* 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>
+ * 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
#include "aes_ccm.h"
-/*
- * Key handling basics
+/**
+ * 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,
* 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.
+ * 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.
*
- * 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.
+ * 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;
+ /* only add if not already added */
+ if (list_empty(&key->todo))
+ list_add(&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;
int ret;
DECLARE_MAC_BUF(mac);
+ assert_key_lock();
+ might_sleep();
+
if (!key->local->ops->set_key)
return;
key->sdata->dev->dev_addr, addr,
&key->conf);
- if (!ret)
+ 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 "
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);
+ assert_key_lock();
+ might_sleep();
+
if (!key || !key->local->ops->set_key)
return;
- if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
- !(key->flags & KEY_FLAG_REMOVE_FROM_HARDWARE))
+ 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);
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);
+ 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->sta_lock, flags);
+ __ieee80211_set_default_key(sdata, idx);
+ spin_unlock_irqrestore(&sdata->local->sta_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,
key->conf.keylen = key_len;
memcpy(key->conf.key, key_data, key_len);
INIT_LIST_HEAD(&key->list);
+ INIT_LIST_HEAD(&key->todo);
if (alg == ALG_CCMP) {
/*
*/
key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
if (!key->u.ccmp.tfm) {
- ieee80211_key_free(key);
+ kfree(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 (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 (new)
- list_add(&new->list, &sdata->key_list);
-
- 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;
+ unsigned long flags;
int idx;
- ASSERT_RTNL();
- might_sleep();
-
BUG_ON(!sdata);
BUG_ON(!key);
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 (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
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 (ap->flags & WLAN_STA_WME)
key->conf.flags |=
IEEE80211_KEY_FLAG_WMM_STA;
- sta_info_put(ap);
}
}
}
+ spin_lock_irqsave(&sdata->local->sta_lock, flags);
+
if (sta)
old_key = sta->key;
else
__ieee80211_key_replace(sdata, sta, old_key, key);
- if (old_key) {
- synchronize_rcu();
- ieee80211_key_free(old_key);
- }
+ spin_unlock_irqrestore(&sdata->local->sta_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))
- ieee80211_key_enable_hw_accel(key);
+ 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)
{
- ASSERT_RTNL();
- might_sleep();
+ unsigned long flags;
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);
+ spin_lock_irqsave(&key->sdata->local->sta_lock, flags);
+ __ieee80211_key_free(key);
+ spin_unlock_irqrestore(&key->sdata->local->sta_lock, flags);
+}
- synchronize_rcu();
+/*
+ * 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;
- /*
- * 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);
- }
+ might_sleep();
- if (key->conf.alg == ALG_CCMP)
- ieee80211_aes_key_free(key->u.ccmp.tfm);
- ieee80211_debugfs_key_remove(key);
+ spin_lock_irqsave(&sdata->local->sta_lock, flags);
+ list_for_each_entry(key, &sdata->key_list, list)
+ add_todo(key, todo_flags);
+ spin_unlock_irqrestore(&sdata->local->sta_lock, flags);
- kfree(key);
+ ieee80211_key_todo();
}
-void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
+void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
{
- struct ieee80211_key *key = NULL;
+ ASSERT_RTNL();
- if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
- key = sdata->keys[idx];
+ if (WARN_ON(!netif_running(sdata->dev)))
+ return;
- if (sdata->default_key != key) {
- ieee80211_debugfs_key_remove_default(sdata);
+ ieee80211_todo_for_each_key(sdata, KEY_FLAG_TODO_HWACCEL_ADD);
+}
- rcu_assign_pointer(sdata->default_key, key);
+void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
+{
+ ASSERT_RTNL();
- if (sdata->default_key)
- ieee80211_debugfs_key_add_default(sdata);
- }
+ ieee80211_todo_for_each_key(sdata, KEY_FLAG_TODO_HWACCEL_REMOVE);
}
-void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
+static void __ieee80211_key_destroy(struct ieee80211_key *key)
{
- struct ieee80211_key *key, *tmp;
- LIST_HEAD(tmp_list);
+ if (!key)
+ return;
- ASSERT_RTNL();
- might_sleep();
+ ieee80211_key_disable_hw_accel(key);
- list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
- ieee80211_key_free(key);
+ if (key->conf.alg == ALG_CCMP)
+ ieee80211_aes_key_free(key->u.ccmp.tfm);
+ ieee80211_debugfs_key_remove(key);
+
+ kfree(key);
}
-void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
+static void __ieee80211_key_todo(void)
{
struct ieee80211_key *key;
+ bool work_done;
+ u32 todoflags;
- ASSERT_RTNL();
- might_sleep();
+ /*
+ * 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;
+ }
- if (WARN_ON(!netif_running(sdata->dev)))
- return;
+ WARN_ON(!work_done);
- list_for_each_entry(key, &sdata->key_list, list)
- ieee80211_key_enable_hw_accel(key);
+ spin_lock(&todo_lock);
+ }
+ spin_unlock(&todo_lock);
}
-void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
+void ieee80211_key_todo(void)
{
- struct ieee80211_key *key;
+ ieee80211_key_lock();
+ __ieee80211_key_todo();
+ ieee80211_key_unlock();
+}
- ASSERT_RTNL();
- might_sleep();
+void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
+{
+ struct ieee80211_key *key, *tmp;
+ unsigned long flags;
- list_for_each_entry(key, &sdata->key_list, list)
- ieee80211_key_disable_hw_accel(key);
+ ieee80211_key_lock();
+
+ ieee80211_debugfs_key_remove_default(sdata);
+
+ spin_lock_irqsave(&sdata->local->sta_lock, flags);
+ list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
+ __ieee80211_key_free(key);
+ spin_unlock_irqrestore(&sdata->local->sta_lock, flags);
+
+ __ieee80211_key_todo();
+
+ ieee80211_key_unlock();
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff