diff options
Diffstat (limited to 'net/mac80211/key.c')
-rw-r--r-- | net/mac80211/key.c | 550 |
1 files changed, 550 insertions, 0 deletions
diff --git a/net/mac80211/key.c b/net/mac80211/key.c new file mode 100644 index 0000000..a5b06fe --- /dev/null +++ b/net/mac80211/key.c @@ -0,0 +1,550 @@ +/* + * 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; + DECLARE_MAC_BUF(mac); + + 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, %s) to hardware (%d)\n", + wiphy_name(key->local->hw.wiphy), + key->conf.keyidx, print_mac(mac, addr), ret); +} + +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; + + 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, %s) from hardware (%d)\n", + 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); +} + +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(); +} |