package/mac80211/src/net/mac80211/key.c

   1 /*
   2  * Copyright 2002-2005, Instant802 Networks, Inc.
   3  * Copyright 2005-2006, Devicescape Software, Inc.
   4  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   5  * Copyright 2007       Johannes Berg <johannes@sipsolutions.net>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/if_ether.h>
  13 #include <linux/etherdevice.h>
  14 #include <linux/list.h>
  15 #include <linux/rcupdate.h>
  16 #include <net/mac80211.h>
  17 #include "ieee80211_i.h"
  18 #include "debugfs_key.h"
  19 #include "aes_ccm.h"
  20
  21
  22 /*
  23  * Key handling basics
  24  *
  25  * Key handling in mac80211 is done based on per-interface (sub_if_data)
  26  * keys and per-station keys. Since each station belongs to an interface,
  27  * each station key also belongs to that interface.
  28  *
  29  * Hardware acceleration is done on a best-effort basis, for each key
  30  * that is eligible the hardware is asked to enable that key but if
  31  * it cannot do that they key is simply kept for software encryption.
  32  * There is currently no way of knowing this except by looking into
  33  * debugfs.
  34  *
  35  * All operations here are called under RTNL so no extra locking is
  36  * required.
  37  */
  38
  39 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
  40 static const u8 zero_addr[ETH_ALEN];
  41
  42 static const u8 *get_mac_for_key(struct ieee80211_key *key)
  43 {
  44         const u8 *addr = bcast_addr;
  45
  46         /*
  47          * If we're an AP we won't ever receive frames with a non-WEP
  48          * group key so we tell the driver that by using the zero MAC
  49          * address to indicate a transmit-only key.
  50          */
  51         if (key->conf.alg != ALG_WEP &&
  52             (key->sdata->type == IEEE80211_IF_TYPE_AP ||
  53              key->sdata->type == IEEE80211_IF_TYPE_VLAN))
  54                 addr = zero_addr;
  55
  56         if (key->sta)
  57                 addr = key->sta->addr;
  58
  59         return addr;
  60 }
  61
  62 static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
  63 {
  64         const u8 *addr;
  65         int ret;
  66
  67         if (!key->local->ops->set_key)
  68                 return;
  69
  70         addr = get_mac_for_key(key);
  71
  72         ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
  73                                        key->sdata->dev->dev_addr, addr,
  74                                        &key->conf);
  75
  76         if (!ret)
  77                 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
  78
  79         if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
  80                 printk(KERN_ERR "mac80211-%s: failed to set key "
  81                        "(%d, " MAC_FMT ") to hardware (%d)\n",
  82                        wiphy_name(key->local->hw.wiphy),
  83                        key->conf.keyidx, MAC_ARG(addr), ret);
  84 }
  85
  86 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
  87 {
  88         const u8 *addr;
  89         int ret;
  90
  91         if (!key->local->ops->set_key)
  92                 return;
  93
  94         if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
  95                 return;
  96
  97         addr = get_mac_for_key(key);
  98
  99         ret = key->local->ops->set_key(local_to_hw(key->local), DISABLE_KEY,
 100                                        key->sdata->dev->dev_addr, addr,
 101                                        &key->conf);
 102
 103         if (ret)
 104                 printk(KERN_ERR "mac80211-%s: failed to remove key "
 105                        "(%d, " MAC_FMT ") from hardware (%d)\n",
 106                        wiphy_name(key->local->hw.wiphy),
 107                        key->conf.keyidx, MAC_ARG(addr), ret);
 108
 109         key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
 110 }
 111
 112 struct ieee80211_key *ieee80211_key_alloc(struct ieee80211_sub_if_data *sdata,
 113                                           struct sta_info *sta,
 114                                           enum ieee80211_key_alg alg,
 115                                           int idx,
 116                                           size_t key_len,
 117                                           const u8 *key_data)
 118 {
 119         struct ieee80211_key *key;
 120
 121         BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS);
 122
 123         key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
 124         if (!key)
 125                 return NULL;
 126
 127         /*
 128          * Default to software encryption; we'll later upload the
 129          * key to the hardware if possible.
 130          */
 131         key->conf.flags = 0;
 132         key->flags = 0;
 133
 134         key->conf.alg = alg;
 135         key->conf.keyidx = idx;
 136         key->conf.keylen = key_len;
 137         memcpy(key->conf.key, key_data, key_len);
 138
 139         key->local = sdata->local;
 140         key->sdata = sdata;
 141         key->sta = sta;
 142
 143         if (alg == ALG_CCMP) {
 144                 /*
 145                  * Initialize AES key state here as an optimization so that
 146                  * it does not need to be initialized for every packet.
 147                  */
 148                 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
 149                 if (!key->u.ccmp.tfm) {
 150                         ieee80211_key_free(key);
 151                         return NULL;
 152                 }
 153         }
 154
 155         ieee80211_debugfs_key_add(key->local, key);
 156
 157         /* remove key first */
 158         if (sta)
 159                 ieee80211_key_free(sta->key);
 160         else
 161                 ieee80211_key_free(sdata->keys[idx]);
 162
 163         if (sta) {
 164                 ieee80211_debugfs_key_sta_link(key, sta);
 165
 166                 /*
 167                  * some hardware cannot handle TKIP with QoS, so
 168                  * we indicate whether QoS could be in use.
 169                  */
 170                 if (sta->flags & WLAN_STA_WME)
 171                         key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
 172         } else {
 173                 if (sdata->type == IEEE80211_IF_TYPE_STA) {
 174                         struct sta_info *ap;
 175
 176                         /* same here, the AP could be using QoS */
 177                         ap = sta_info_get(key->local, key->sdata->u.sta.bssid);
 178                         if (ap) {
 179                                 if (ap->flags & WLAN_STA_WME)
 180                                         key->conf.flags |=
 181                                                 IEEE80211_KEY_FLAG_WMM_STA;
 182                                 sta_info_put(ap);
 183                         }
 184                 }
 185         }
 186
 187         /* enable hwaccel if appropriate */
 188         if (netif_running(key->sdata->dev))
 189                 ieee80211_key_enable_hw_accel(key);
 190
 191         if (sta)
 192                 rcu_assign_pointer(sta->key, key);
 193         else
 194                 rcu_assign_pointer(sdata->keys[idx], key);
 195
 196         list_add(&key->list, &sdata->key_list);
 197
 198         return key;
 199 }
 200
 201 void ieee80211_key_free(struct ieee80211_key *key)
 202 {
 203         if (!key)
 204                 return;
 205
 206         if (key->sta) {
 207                 rcu_assign_pointer(key->sta->key, NULL);
 208         } else {
 209                 if (key->sdata->default_key == key)
 210                         ieee80211_set_default_key(key->sdata, -1);
 211                 if (key->conf.keyidx >= 0 &&
 212                     key->conf.keyidx < NUM_DEFAULT_KEYS)
 213                         rcu_assign_pointer(key->sdata->keys[key->conf.keyidx],
 214                                            NULL);
 215                 else
 216                         WARN_ON(1);
 217         }
 218
 219         /* wait for all key users to complete */
 220         synchronize_rcu();
 221
 222         /* remove from hwaccel if appropriate */
 223         ieee80211_key_disable_hw_accel(key);
 224
 225         if (key->conf.alg == ALG_CCMP)
 226                 ieee80211_aes_key_free(key->u.ccmp.tfm);
 227         ieee80211_debugfs_key_remove(key);
 228
 229         list_del(&key->list);
 230
 231         kfree(key);
 232 }
 233
 234 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
 235 {
 236         struct ieee80211_key *key = NULL;
 237
 238         if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
 239                 key = sdata->keys[idx];
 240
 241         if (sdata->default_key != key) {
 242                 ieee80211_debugfs_key_remove_default(sdata);
 243
 244                 rcu_assign_pointer(sdata->default_key, key);
 245
 246                 if (sdata->default_key)
 247                         ieee80211_debugfs_key_add_default(sdata);
 248         }
 249 }
 250
 251 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
 252 {
 253         struct ieee80211_key *key, *tmp;
 254
 255         list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
 256                 ieee80211_key_free(key);
 257 }
 258
 259 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
 260 {
 261         struct ieee80211_key *key;
 262
 263         WARN_ON(!netif_running(sdata->dev));
 264         if (!netif_running(sdata->dev))
 265                 return;
 266
 267         list_for_each_entry(key, &sdata->key_list, list)
 268                 ieee80211_key_enable_hw_accel(key);
 269 }
 270
 271 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
 272 {
 273         struct ieee80211_key *key;
 274
 275         list_for_each_entry(key, &sdata->key_list, list)
 276                 ieee80211_key_disable_hw_accel(key);
 277 }