git.oblomov.eu Git - linux-2.6/blob - 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 <net/mac80211.h>
  16 #include "ieee80211_i.h"
  17 #include "debugfs_key.h"
  18 #include "aes_ccm.h"
  19
  20
  21 /*
  22  * Key handling basics
  23  *
  24  * Key handling in mac80211 is done based on per-interface (sub_if_data)
  25  * keys and per-station keys. Since each station belongs to an interface,
  26  * each station key also belongs to that interface.
  27  *
  28  * Hardware acceleration is done on a best-effort basis, for each key
  29  * that is eligible the hardware is asked to enable that key but if
  30  * it cannot do that they key is simply kept for software encryption.
  31  * There is currently no way of knowing this except by looking into
  32  * debugfs.
  33  *
  34  * All operations here are called under RTNL so no extra locking is
  35  * required.
  36  */
  37
  38 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
  39 static const u8 zero_addr[ETH_ALEN];
  40
  41 static const u8 *get_mac_for_key(struct ieee80211_key *key)
  42 {
  43         const u8 *addr = bcast_addr;
  44
  45         /*
  46          * If we're an AP we won't ever receive frames with a non-WEP
  47          * group key so we tell the driver that by using the zero MAC
  48          * address to indicate a transmit-only key.
  49          */
  50         if (key->conf.alg != ALG_WEP &&
  51             (key->sdata->type == IEEE80211_IF_TYPE_AP ||
  52              key->sdata->type == IEEE80211_IF_TYPE_VLAN))
  53                 addr = zero_addr;
  54
  55         if (key->sta)
  56                 addr = key->sta->addr;
  57
  58         return addr;
  59 }
  60
  61 static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
  62 {
  63         const u8 *addr;
  64         int ret;
  65
  66         if (!key->local->ops->set_key)
  67                 return;
  68
  69         addr = get_mac_for_key(key);
  70
  71         ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
  72                                        key->sdata->dev->dev_addr, addr,
  73                                        &key->conf);
  74
  75         WARN_ON(!ret && (key->conf.hw_key_idx == HW_KEY_IDX_INVALID));
  76
  77         if (!ret)
  78                 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
  79
  80         if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
  81                 printk(KERN_ERR "mac80211-%s: failed to set key "
  82                        "(%d, " MAC_FMT ") to hardware (%d)\n",
  83                        wiphy_name(key->local->hw.wiphy),
  84                        key->conf.keyidx, MAC_ARG(addr), ret);
  85 }
  86
  87 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
  88 {
  89         const u8 *addr;
  90         int ret;
  91
  92         if (!key->local->ops->set_key)
  93                 return;
  94
  95         if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
  96                 return;
  97
  98         addr = get_mac_for_key(key);
  99
 100         ret = key->local->ops->set_key(local_to_hw(key->local), DISABLE_KEY,
 101                                        key->sdata->dev->dev_addr, addr,
 102                                        &key->conf);
 103
 104         if (ret)
 105                 printk(KERN_ERR "mac80211-%s: failed to remove key "
 106                        "(%d, " MAC_FMT ") from hardware (%d)\n",
 107                        wiphy_name(key->local->hw.wiphy),
 108                        key->conf.keyidx, MAC_ARG(addr), ret);
 109
 110         key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
 111         key->conf.hw_key_idx = HW_KEY_IDX_INVALID;
 112 }
 113
 114 struct ieee80211_key *ieee80211_key_alloc(struct ieee80211_sub_if_data *sdata,
 115                                           struct sta_info *sta,
 116                                           ieee80211_key_alg alg,
 117                                           int idx,
 118                                           size_t key_len,
 119                                           const u8 *key_data)
 120 {
 121         struct ieee80211_key *key;
 122
 123         BUG_ON(alg == ALG_NONE);
 124
 125         key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
 126         if (!key)
 127                 return NULL;
 128
 129         /*
 130          * Default to software encryption; we'll later upload the
 131          * key to the hardware if possible.
 132          */
 133         key->conf.hw_key_idx = HW_KEY_IDX_INVALID;
 134         key->conf.flags = 0;
 135         key->flags = 0;
 136
 137         key->conf.alg = alg;
 138         key->conf.keyidx = idx;
 139         key->conf.keylen = key_len;
 140         memcpy(key->conf.key, key_data, key_len);
 141
 142         key->local = sdata->local;
 143         key->sdata = sdata;
 144         key->sta = sta;
 145
 146         if (alg == ALG_CCMP) {
 147                 /*
 148                  * Initialize AES key state here as an optimization so that
 149                  * it does not need to be initialized for every packet.
 150                  */
 151                 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
 152                 if (!key->u.ccmp.tfm) {
 153                         ieee80211_key_free(key);
 154                         return NULL;
 155                 }
 156         }
 157
 158         ieee80211_debugfs_key_add(key->local, key);
 159
 160         if (sta) {
 161                 ieee80211_debugfs_key_sta_link(key, sta);
 162                 sta->key = key;
 163                 /*
 164                  * some hardware cannot handle TKIP with QoS, so
 165                  * we indicate whether QoS could be in use.
 166                  */
 167                 if (sta->flags & WLAN_STA_WME)
 168                         key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
 169         } else {
 170                 if (sdata->type == IEEE80211_IF_TYPE_STA) {
 171                         struct sta_info *ap;
 172
 173                         /* same here, the AP could be using QoS */
 174                         ap = sta_info_get(key->local, key->sdata->u.sta.bssid);
 175                         if (ap) {
 176                                 if (ap->flags & WLAN_STA_WME)
 177                                         key->conf.flags |=
 178                                                 IEEE80211_KEY_FLAG_WMM_STA;
 179                                 sta_info_put(ap);
 180                         }
 181                 }
 182
 183                 if (idx >= 0 && idx < NUM_DEFAULT_KEYS) {
 184                         if (!sdata->keys[idx])
 185                                 sdata->keys[idx] = key;
 186                         else
 187                                 WARN_ON(1);
 188                 } else
 189                         WARN_ON(1);
 190         }
 191
 192         list_add(&key->list, &sdata->key_list);
 193
 194         if (netif_running(key->sdata->dev))
 195                 ieee80211_key_enable_hw_accel(key);
 196
 197         return key;
 198 }
 199
 200 void ieee80211_key_free(struct ieee80211_key *key)
 201 {
 202         if (!key)
 203                 return;
 204
 205         ieee80211_key_disable_hw_accel(key);
 206
 207         if (key->sta) {
 208                 key->sta->key = NULL;
 209         } else {
 210                 if (key->sdata->default_key == key)
 211                         ieee80211_set_default_key(key->sdata, -1);
 212                 if (key->conf.keyidx >= 0 &&
 213                     key->conf.keyidx < NUM_DEFAULT_KEYS)
 214                         key->sdata->keys[key->conf.keyidx] = NULL;
 215                 else
 216                         WARN_ON(1);
 217         }
 218
 219         if (key->conf.alg == ALG_CCMP)
 220                 ieee80211_aes_key_free(key->u.ccmp.tfm);
 221         ieee80211_debugfs_key_remove(key);
 222
 223         list_del(&key->list);
 224
 225         kfree(key);
 226 }
 227
 228 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
 229 {
 230         struct ieee80211_key *key = NULL;
 231
 232         if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
 233                 key = sdata->keys[idx];
 234
 235         if (sdata->default_key != key) {
 236                 ieee80211_debugfs_key_remove_default(sdata);
 237
 238                 sdata->default_key = key;
 239
 240                 if (sdata->default_key)
 241                         ieee80211_debugfs_key_add_default(sdata);
 242
 243                 if (sdata->local->ops->set_key_idx)
 244                         sdata->local->ops->set_key_idx(
 245                                 local_to_hw(sdata->local), idx);
 246         }
 247 }
 248
 249 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
 250 {
 251         struct ieee80211_key *key, *tmp;
 252
 253         list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
 254                 ieee80211_key_free(key);
 255 }
 256
 257 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
 258 {
 259         struct ieee80211_key *key;
 260
 261         WARN_ON(!netif_running(sdata->dev));
 262         if (!netif_running(sdata->dev))
 263                 return;
 264
 265         list_for_each_entry(key, &sdata->key_list, list)
 266                 ieee80211_key_enable_hw_accel(key);
 267 }
 268
 269 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
 270 {
 271         struct ieee80211_key *key;
 272
 273         list_for_each_entry(key, &sdata->key_list, list)
 274                 ieee80211_key_disable_hw_accel(key);
 275 }