1 files changed, 293 insertions, 75 deletions

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index ed57fb8e82fc..711e36e54ff8 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -2,7 +2,7 @@
  * 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
@@ -13,14 +13,15 @@
 #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"
 
 
-/*
- * 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,
@@ -32,13 +33,78 @@
  * 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.
+ *
+ * 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;
@@ -65,6 +131,9 @@ static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
         int ret;
         DECLARE_MAC_BUF(mac);
 
+        assert_key_lock();
+        might_sleep();
+
         if (!key->local->ops->set_key)
                 return;
 
@@ -74,8 +143,11 @@ static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
                                        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 "
@@ -90,11 +162,18 @@ static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
         int ret;
         DECLARE_MAC_BUF(mac);
 
-        if (!key->local->ops->set_key)
+        assert_key_lock();
+        might_sleep();
+
+        if (!key || !key->local->ops->set_key)
                 return;
 
-        if (!(key->flags & KEY_FLAG_UPLOADED_TO_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);
 
@@ -108,12 +187,75 @@ static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
                        wiphy_name(key->local->hw.wiphy),
                        key->conf.keyidx, print_mac(mac, addr), ret);
 
+        spin_lock(&todo_lock);
         key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
+        spin_unlock(&todo_lock);
 }
 
-struct ieee80211_key *ieee80211_key_alloc(struct ieee80211_sub_if_data *sdata,
-                                          struct sta_info *sta,
-                                          enum ieee80211_key_alg alg,
+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,
                                           int idx,
                                           size_t key_len,
                                           const u8 *key_data)
@@ -137,10 +279,8 @@ struct ieee80211_key *ieee80211_key_alloc(struct ieee80211_sub_if_data *sdata,
         key->conf.keyidx = idx;
         key->conf.keylen = key_len;
         memcpy(key->conf.key, key_data, key_len);
-
-        key->local = sdata->local;
-        key->sdata = sdata;
-        key->sta = sta;
+        INIT_LIST_HEAD(&key->list);
+        INIT_LIST_HEAD(&key->todo);
 
         if (alg == ALG_CCMP) {
                 /*
@@ -149,22 +289,31 @@ struct ieee80211_key *ieee80211_key_alloc(struct ieee80211_sub_if_data *sdata,
                  */
                 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
                 if (!key->u.ccmp.tfm) {
-                        ieee80211_key_free(key);
+                        kfree(key);
                         return NULL;
                 }
         }
 
-        ieee80211_debugfs_key_add(key->local, key);
+        return key;
+}
 
-        /* remove key first */
-        if (sta)
-                ieee80211_key_free(sta->key);
-        else
-                ieee80211_key_free(sdata->keys[idx]);
+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;
 
-        if (sta) {
-                ieee80211_debugfs_key_sta_link(key, sta);
+        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.
@@ -175,105 +324,174 @@ struct ieee80211_key *ieee80211_key_alloc(struct ieee80211_sub_if_data *sdata,
                 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);
                         }
                 }
         }
 
-        /* enable hwaccel if appropriate */
-        if (netif_running(key->sdata->dev))
-                ieee80211_key_enable_hw_accel(key);
+        spin_lock_irqsave(&sdata->local->sta_lock, flags);
 
         if (sta)
-                rcu_assign_pointer(sta->key, key);
+                old_key = sta->key;
         else
-                rcu_assign_pointer(sdata->keys[idx], key);
+                old_key = sdata->keys[idx];
 
-        list_add(&key->list, &sdata->key_list);
+        __ieee80211_key_replace(sdata, sta, old_key, key);
 
-        return 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))
+                add_todo(key, KEY_FLAG_TODO_HWACCEL);
 }
 
 void ieee80211_key_free(struct ieee80211_key *key)
 {
+        unsigned long flags;
+
         if (!key)
                 return;
 
-        if (key->sta) {
-                rcu_assign_pointer(key->sta->key, NULL);
-        } else {
-                if (key->sdata->default_key == key)
-                        ieee80211_set_default_key(key->sdata, -1);
-                if (key->conf.keyidx >= 0 &&
-                    key->conf.keyidx < NUM_DEFAULT_KEYS)
-                        rcu_assign_pointer(key->sdata->keys[key->conf.keyidx],
-                                           NULL);
-                else
-                        WARN_ON(1);
+        /*
+         * Replace key with nothingness if it was ever used.
+         */
+        if (key->sdata) {
+                spin_lock_irqsave(&key->sdata->local->sta_lock, flags);
+                __ieee80211_key_replace(key->sdata, key->sta,
+                                        key, NULL);
+                spin_unlock_irqrestore(&key->sdata->local->sta_lock, flags);
         }
 
-        /* wait for all key users to complete */
-        synchronize_rcu();
+        add_todo(key, KEY_FLAG_TODO_DELETE);
+}
+
+void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_key *key;
+
+        might_sleep();
+
+        if (WARN_ON(!netif_running(sdata->dev)))
+                return;
+
+        ieee80211_key_lock();
+
+        list_for_each_entry(key, &sdata->key_list, list)
+                ieee80211_key_enable_hw_accel(key);
+
+        ieee80211_key_unlock();
+}
+
+void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_key *key;
+
+        might_sleep();
+
+        ieee80211_key_lock();
+
+        list_for_each_entry(key, &sdata->key_list, list)
+                ieee80211_key_disable_hw_accel(key);
+
+        ieee80211_key_unlock();
+}
+
+static void __ieee80211_key_free(struct ieee80211_key *key)
+{
+        if (!key)
+                return;
 
-        /* remove from hwaccel if appropriate */
         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);
 
-        list_del(&key->list);
-
         kfree(key);
 }
 
-void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
+static void __ieee80211_key_todo(void)
 {
-        struct ieee80211_key *key = NULL;
+        struct ieee80211_key *key;
+        bool work_done;
+        u32 todoflags;
 
-        if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
-                key = sdata->keys[idx];
+        /*
+         * NB: sta_info_destroy relies on this!
+         */
+        synchronize_rcu();
 
-        if (sdata->default_key != key) {
-                ieee80211_debugfs_key_remove_default(sdata);
+        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 |
+                                          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) {
+                        ieee80211_key_enable_hw_accel(key);
+                        work_done = true;
+                }
+                if (todoflags & KEY_FLAG_TODO_DELETE) {
+                        __ieee80211_key_free(key);
+                        work_done = true;
+                }
 
-                rcu_assign_pointer(sdata->default_key, key);
+                WARN_ON(!work_done);
 
-                if (sdata->default_key)
-                        ieee80211_debugfs_key_add_default(sdata);
+                spin_lock(&todo_lock);
         }
+        spin_unlock(&todo_lock);
 }
 
-void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
+void ieee80211_key_todo(void)
 {
-        struct ieee80211_key *key, *tmp;
-
-        list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
-                ieee80211_key_free(key);
+        ieee80211_key_lock();
+        __ieee80211_key_todo();
+        ieee80211_key_unlock();
 }
 
-void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
+void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
 {
-        struct ieee80211_key *key;
+        struct ieee80211_key *key, *tmp;
+        LIST_HEAD(tmp_list);
 
-        WARN_ON(!netif_running(sdata->dev));
-        if (!netif_running(sdata->dev))
-                return;
+        ieee80211_key_lock();
 
-        list_for_each_entry(key, &sdata->key_list, list)
-                ieee80211_key_enable_hw_accel(key);
-}
+        ieee80211_debugfs_key_remove_default(sdata);
 
-void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
-{
-        struct ieee80211_key *key;
+        list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
+                ieee80211_key_free(key);
 
-        list_for_each_entry(key, &sdata->key_list, list)
-                ieee80211_key_disable_hw_accel(key);
+        __ieee80211_key_todo();
+
+        ieee80211_key_unlock();
 }