369 lines
8.6 KiB
C
369 lines
8.6 KiB
C
/*
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* Copyright 2002-2005, Instant802 Networks, Inc.
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* Copyright 2005-2006, Devicescape Software, Inc.
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* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
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* Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/if_ether.h>
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#include <linux/etherdevice.h>
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#include <linux/list.h>
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#include <linux/rcupdate.h>
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#include <linux/rtnetlink.h>
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#include <net/mac80211.h>
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#include "ieee80211_i.h"
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#include "debugfs_key.h"
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#include "aes_ccm.h"
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/**
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* DOC: Key handling basics
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*
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* Key handling in mac80211 is done based on per-interface (sub_if_data)
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* keys and per-station keys. Since each station belongs to an interface,
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* each station key also belongs to that interface.
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*
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* Hardware acceleration is done on a best-effort basis, for each key
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* that is eligible the hardware is asked to enable that key but if
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* it cannot do that they key is simply kept for software encryption.
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* There is currently no way of knowing this except by looking into
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* debugfs.
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*
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* All operations here are called under RTNL so no extra locking is
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* required.
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*
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* NOTE: This code requires that sta info *destruction* is done under
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* RTNL, otherwise it can try to access already freed STA structs
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* when a STA key is being freed.
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*/
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static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
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static const u8 zero_addr[ETH_ALEN];
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static const u8 *get_mac_for_key(struct ieee80211_key *key)
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{
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const u8 *addr = bcast_addr;
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/*
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* If we're an AP we won't ever receive frames with a non-WEP
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* group key so we tell the driver that by using the zero MAC
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* address to indicate a transmit-only key.
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*/
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if (key->conf.alg != ALG_WEP &&
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(key->sdata->vif.type == IEEE80211_IF_TYPE_AP ||
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key->sdata->vif.type == IEEE80211_IF_TYPE_VLAN))
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addr = zero_addr;
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if (key->sta)
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addr = key->sta->addr;
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return addr;
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}
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static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
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{
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const u8 *addr;
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int ret;
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DECLARE_MAC_BUF(mac);
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if (!key->local->ops->set_key)
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return;
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addr = get_mac_for_key(key);
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ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
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key->sdata->dev->dev_addr, addr,
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&key->conf);
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if (!ret)
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key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
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if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
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printk(KERN_ERR "mac80211-%s: failed to set key "
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"(%d, %s) to hardware (%d)\n",
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wiphy_name(key->local->hw.wiphy),
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key->conf.keyidx, print_mac(mac, addr), ret);
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}
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static void ieee80211_key_mark_hw_accel_off(struct ieee80211_key *key)
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{
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if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
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key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
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key->flags |= KEY_FLAG_REMOVE_FROM_HARDWARE;
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}
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}
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static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
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{
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const u8 *addr;
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int ret;
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DECLARE_MAC_BUF(mac);
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if (!key || !key->local->ops->set_key)
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return;
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if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
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!(key->flags & KEY_FLAG_REMOVE_FROM_HARDWARE))
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return;
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addr = get_mac_for_key(key);
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ret = key->local->ops->set_key(local_to_hw(key->local), DISABLE_KEY,
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key->sdata->dev->dev_addr, addr,
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&key->conf);
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if (ret)
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printk(KERN_ERR "mac80211-%s: failed to remove key "
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"(%d, %s) from hardware (%d)\n",
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wiphy_name(key->local->hw.wiphy),
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key->conf.keyidx, print_mac(mac, addr), ret);
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key->flags &= ~(KEY_FLAG_UPLOADED_TO_HARDWARE |
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KEY_FLAG_REMOVE_FROM_HARDWARE);
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}
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struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
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int idx,
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size_t key_len,
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const u8 *key_data)
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{
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struct ieee80211_key *key;
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BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS);
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key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
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if (!key)
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return NULL;
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/*
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* Default to software encryption; we'll later upload the
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* key to the hardware if possible.
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*/
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key->conf.flags = 0;
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key->flags = 0;
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key->conf.alg = alg;
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key->conf.keyidx = idx;
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key->conf.keylen = key_len;
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memcpy(key->conf.key, key_data, key_len);
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INIT_LIST_HEAD(&key->list);
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if (alg == ALG_CCMP) {
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/*
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* Initialize AES key state here as an optimization so that
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* it does not need to be initialized for every packet.
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*/
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key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
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if (!key->u.ccmp.tfm) {
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ieee80211_key_free(key);
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return NULL;
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}
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}
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return key;
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}
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static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
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struct sta_info *sta,
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struct ieee80211_key *key,
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struct ieee80211_key *new)
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{
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int idx, defkey;
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if (new)
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list_add(&new->list, &sdata->key_list);
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if (sta) {
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rcu_assign_pointer(sta->key, new);
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} else {
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WARN_ON(new && key && new->conf.keyidx != key->conf.keyidx);
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if (key)
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idx = key->conf.keyidx;
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else
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idx = new->conf.keyidx;
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defkey = key && sdata->default_key == key;
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if (defkey && !new)
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ieee80211_set_default_key(sdata, -1);
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rcu_assign_pointer(sdata->keys[idx], new);
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if (defkey && new)
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ieee80211_set_default_key(sdata, new->conf.keyidx);
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}
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if (key) {
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ieee80211_key_mark_hw_accel_off(key);
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/*
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* We'll use an empty list to indicate that the key
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* has already been removed.
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*/
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list_del_init(&key->list);
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}
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}
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void ieee80211_key_link(struct ieee80211_key *key,
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struct ieee80211_sub_if_data *sdata,
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struct sta_info *sta)
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{
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struct ieee80211_key *old_key;
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int idx;
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ASSERT_RTNL();
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might_sleep();
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BUG_ON(!sdata);
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BUG_ON(!key);
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idx = key->conf.keyidx;
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key->local = sdata->local;
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key->sdata = sdata;
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key->sta = sta;
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ieee80211_debugfs_key_add(key->local, key);
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if (sta) {
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ieee80211_debugfs_key_sta_link(key, sta);
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/*
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* some hardware cannot handle TKIP with QoS, so
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* we indicate whether QoS could be in use.
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*/
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if (sta->flags & WLAN_STA_WME)
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key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
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} else {
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if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
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struct sta_info *ap;
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rcu_read_lock();
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/* same here, the AP could be using QoS */
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ap = sta_info_get(key->local, key->sdata->u.sta.bssid);
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if (ap) {
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if (ap->flags & WLAN_STA_WME)
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key->conf.flags |=
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IEEE80211_KEY_FLAG_WMM_STA;
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}
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rcu_read_unlock();
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}
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}
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if (sta)
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old_key = sta->key;
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else
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old_key = sdata->keys[idx];
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__ieee80211_key_replace(sdata, sta, old_key, key);
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if (old_key) {
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synchronize_rcu();
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ieee80211_key_free(old_key);
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}
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if (netif_running(sdata->dev))
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ieee80211_key_enable_hw_accel(key);
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}
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void ieee80211_key_free(struct ieee80211_key *key)
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{
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ASSERT_RTNL();
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might_sleep();
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if (!key)
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return;
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if (key->sdata) {
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/*
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* Replace key with nothingness.
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*
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* Because other code may have key reference (RCU protected)
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* right now, we then wait for a grace period before freeing
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* it.
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* An empty list indicates it was never added to the key list
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* or has been removed already. It may, however, still be in
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* hardware for acceleration.
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*/
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if (!list_empty(&key->list))
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__ieee80211_key_replace(key->sdata, key->sta,
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key, NULL);
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/*
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* Do NOT remove this without looking at sta_info_destroy()
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*/
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synchronize_rcu();
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/*
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* Remove from hwaccel if appropriate, this will
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* only happen when the key is actually unlinked,
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* it will already be done when the key was replaced.
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*/
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ieee80211_key_disable_hw_accel(key);
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}
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if (key->conf.alg == ALG_CCMP)
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ieee80211_aes_key_free(key->u.ccmp.tfm);
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ieee80211_debugfs_key_remove(key);
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kfree(key);
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}
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void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
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{
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struct ieee80211_key *key = NULL;
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if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
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key = sdata->keys[idx];
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if (sdata->default_key != key) {
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ieee80211_debugfs_key_remove_default(sdata);
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rcu_assign_pointer(sdata->default_key, key);
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if (sdata->default_key)
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ieee80211_debugfs_key_add_default(sdata);
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}
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}
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void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_key *key, *tmp;
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LIST_HEAD(tmp_list);
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ASSERT_RTNL();
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might_sleep();
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list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
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ieee80211_key_free(key);
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}
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void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_key *key;
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ASSERT_RTNL();
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might_sleep();
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if (WARN_ON(!netif_running(sdata->dev)))
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return;
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list_for_each_entry(key, &sdata->key_list, list)
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ieee80211_key_enable_hw_accel(key);
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}
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void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_key *key;
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ASSERT_RTNL();
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might_sleep();
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list_for_each_entry(key, &sdata->key_list, list)
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ieee80211_key_disable_hw_accel(key);
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}
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