SAFE public projects git trees. - safe/jmp/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 <linux/rcupdate.h>
  16 #include <linux/rtnetlink.h>
  17 #include <net/mac80211.h>
  18 #include "ieee80211_i.h"
  19 #include "debugfs_key.h"
  20 #include "aes_ccm.h"
  21
  22
  23 /*
  24  * Key handling basics
  25  *
  26  * Key handling in mac80211 is done based on per-interface (sub_if_data)
  27  * keys and per-station keys. Since each station belongs to an interface,
  28  * each station key also belongs to that interface.
  29  *
  30  * Hardware acceleration is done on a best-effort basis, for each key
  31  * that is eligible the hardware is asked to enable that key but if
  32  * it cannot do that they key is simply kept for software encryption.
  33  * There is currently no way of knowing this except by looking into
  34  * debugfs.
  35  *
  36  * All operations here are called under RTNL so no extra locking is
  37  * required.
  38  *
  39  * NOTE: This code requires that sta info *destruction* is done under
  40  *       RTNL, otherwise it can try to access already freed STA structs
  41  *       when a STA key is being freed.
  42  */
  43
  44 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
  45 static const u8 zero_addr[ETH_ALEN];
  46
  47 static const u8 *get_mac_for_key(struct ieee80211_key *key)
  48 {
  49         const u8 *addr = bcast_addr;
  50
  51         /*
  52          * If we're an AP we won't ever receive frames with a non-WEP
  53          * group key so we tell the driver that by using the zero MAC
  54          * address to indicate a transmit-only key.
  55          */
  56         if (key->conf.alg != ALG_WEP &&
  57             (key->sdata->vif.type == IEEE80211_IF_TYPE_AP ||
  58              key->sdata->vif.type == IEEE80211_IF_TYPE_VLAN))
  59                 addr = zero_addr;
  60
  61         if (key->sta)
  62                 addr = key->sta->addr;
  63
  64         return addr;
  65 }
  66
  67 static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
  68 {
  69         const u8 *addr;
  70         int ret;
  71         DECLARE_MAC_BUF(mac);
  72
  73         if (!key->local->ops->set_key)
  74                 return;
  75
  76         addr = get_mac_for_key(key);
  77
  78         ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
  79                                        key->sdata->dev->dev_addr, addr,
  80                                        &key->conf);
  81
  82         if (!ret)
  83                 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
  84
  85         if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
  86                 printk(KERN_ERR "mac80211-%s: failed to set key "
  87                        "(%d, %s) to hardware (%d)\n",
  88                        wiphy_name(key->local->hw.wiphy),
  89                        key->conf.keyidx, print_mac(mac, addr), ret);
  90 }
  91
  92 static void ieee80211_key_mark_hw_accel_off(struct ieee80211_key *key)
  93 {
  94         if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
  95                 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
  96                 key->flags |= KEY_FLAG_REMOVE_FROM_HARDWARE;
  97         }
  98 }
  99
 100 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
 101 {
 102         const u8 *addr;
 103         int ret;
 104         DECLARE_MAC_BUF(mac);
 105
 106         if (!key || !key->local->ops->set_key)
 107                 return;
 108
 109         if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
 110             !(key->flags & KEY_FLAG_REMOVE_FROM_HARDWARE))
 111                 return;
 112
 113         addr = get_mac_for_key(key);
 114
 115         ret = key->local->ops->set_key(local_to_hw(key->local), DISABLE_KEY,
 116                                        key->sdata->dev->dev_addr, addr,
 117                                        &key->conf);
 118
 119         if (ret)
 120                 printk(KERN_ERR "mac80211-%s: failed to remove key "
 121                        "(%d, %s) from hardware (%d)\n",
 122                        wiphy_name(key->local->hw.wiphy),
 123                        key->conf.keyidx, print_mac(mac, addr), ret);
 124
 125         key->flags &= ~(KEY_FLAG_UPLOADED_TO_HARDWARE |
 126                         KEY_FLAG_REMOVE_FROM_HARDWARE);
 127 }
 128
 129 struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
 130                                           int idx,
 131                                           size_t key_len,
 132                                           const u8 *key_data)
 133 {
 134         struct ieee80211_key *key;
 135
 136         BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS);
 137
 138         key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
 139         if (!key)
 140                 return NULL;
 141
 142         /*
 143          * Default to software encryption; we'll later upload the
 144          * key to the hardware if possible.
 145          */
 146         key->conf.flags = 0;
 147         key->flags = 0;
 148
 149         key->conf.alg = alg;
 150         key->conf.keyidx = idx;
 151         key->conf.keylen = key_len;
 152         memcpy(key->conf.key, key_data, key_len);
 153         INIT_LIST_HEAD(&key->list);
 154
 155         if (alg == ALG_CCMP) {
 156                 /*
 157                  * Initialize AES key state here as an optimization so that
 158                  * it does not need to be initialized for every packet.
 159                  */
 160                 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
 161                 if (!key->u.ccmp.tfm) {
 162                         ieee80211_key_free(key);
 163                         return NULL;
 164                 }
 165         }
 166
 167         return key;
 168 }
 169
 170 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
 171                                     struct sta_info *sta,
 172                                     struct ieee80211_key *key,
 173                                     struct ieee80211_key *new)
 174 {
 175         int idx, defkey;
 176
 177         if (sta) {
 178                 rcu_assign_pointer(sta->key, new);
 179         } else {
 180                 WARN_ON(new && key && new->conf.keyidx != key->conf.keyidx);
 181
 182                 if (key)
 183                         idx = key->conf.keyidx;
 184                 else
 185                         idx = new->conf.keyidx;
 186
 187                 defkey = key && sdata->default_key == key;
 188
 189                 if (defkey && !new)
 190                         ieee80211_set_default_key(sdata, -1);
 191
 192                 rcu_assign_pointer(sdata->keys[idx], new);
 193                 if (new)
 194                         list_add(&new->list, &sdata->key_list);
 195
 196                 if (defkey && new)
 197                         ieee80211_set_default_key(sdata, new->conf.keyidx);
 198         }
 199
 200         if (key) {
 201                 ieee80211_key_mark_hw_accel_off(key);
 202                 /*
 203                  * We'll use an empty list to indicate that the key
 204                  * has already been removed.
 205                  */
 206                 list_del_init(&key->list);
 207         }
 208 }
 209
 210 void ieee80211_key_link(struct ieee80211_key *key,
 211                         struct ieee80211_sub_if_data *sdata,
 212                         struct sta_info *sta)
 213 {
 214         struct ieee80211_key *old_key;
 215         int idx;
 216
 217         ASSERT_RTNL();
 218         might_sleep();
 219
 220         BUG_ON(!sdata);
 221         BUG_ON(!key);
 222
 223         idx = key->conf.keyidx;
 224         key->local = sdata->local;
 225         key->sdata = sdata;
 226         key->sta = sta;
 227
 228         ieee80211_debugfs_key_add(key->local, key);
 229
 230         if (sta) {
 231                 ieee80211_debugfs_key_sta_link(key, sta);
 232
 233                 /*
 234                  * some hardware cannot handle TKIP with QoS, so
 235                  * we indicate whether QoS could be in use.
 236                  */
 237                 if (sta->flags & WLAN_STA_WME)
 238                         key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
 239         } else {
 240                 if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
 241                         struct sta_info *ap;
 242
 243                         rcu_read_lock();
 244
 245                         /* same here, the AP could be using QoS */
 246                         ap = sta_info_get(key->local, key->sdata->u.sta.bssid);
 247                         if (ap) {
 248                                 if (ap->flags & WLAN_STA_WME)
 249                                         key->conf.flags |=
 250                                                 IEEE80211_KEY_FLAG_WMM_STA;
 251                         }
 252
 253                         rcu_read_unlock();
 254                 }
 255         }
 256
 257         if (sta)
 258                 old_key = sta->key;
 259         else
 260                 old_key = sdata->keys[idx];
 261
 262         __ieee80211_key_replace(sdata, sta, old_key, key);
 263
 264         if (old_key) {
 265                 synchronize_rcu();
 266                 ieee80211_key_free(old_key);
 267         }
 268
 269         if (netif_running(sdata->dev))
 270                 ieee80211_key_enable_hw_accel(key);
 271 }
 272
 273 void ieee80211_key_free(struct ieee80211_key *key)
 274 {
 275         ASSERT_RTNL();
 276         might_sleep();
 277
 278         if (!key)
 279                 return;
 280
 281         if (key->sdata) {
 282                 /*
 283                  * Replace key with nothingness.
 284                  *
 285                  * Because other code may have key reference (RCU protected)
 286                  * right now, we then wait for a grace period before freeing
 287                  * it.
 288                  * An empty list indicates it was never added to the key list
 289                  * or has been removed already. It may, however, still be in
 290                  * hardware for acceleration.
 291                  */
 292                 if (!list_empty(&key->list))
 293                         __ieee80211_key_replace(key->sdata, key->sta,
 294                                                 key, NULL);
 295
 296                 /*
 297                  * Do NOT remove this without looking at sta_info_destroy()
 298                  */
 299                 synchronize_rcu();
 300
 301                 /*
 302                  * Remove from hwaccel if appropriate, this will
 303                  * only happen when the key is actually unlinked,
 304                  * it will already be done when the key was replaced.
 305                  */
 306                 ieee80211_key_disable_hw_accel(key);
 307         }
 308
 309         if (key->conf.alg == ALG_CCMP)
 310                 ieee80211_aes_key_free(key->u.ccmp.tfm);
 311         ieee80211_debugfs_key_remove(key);
 312
 313         kfree(key);
 314 }
 315
 316 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
 317 {
 318         struct ieee80211_key *key = NULL;
 319
 320         if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
 321                 key = sdata->keys[idx];
 322
 323         if (sdata->default_key != key) {
 324                 ieee80211_debugfs_key_remove_default(sdata);
 325
 326                 rcu_assign_pointer(sdata->default_key, key);
 327
 328                 if (sdata->default_key)
 329                         ieee80211_debugfs_key_add_default(sdata);
 330         }
 331 }
 332
 333 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
 334 {
 335         struct ieee80211_key *key, *tmp;
 336         LIST_HEAD(tmp_list);
 337
 338         ASSERT_RTNL();
 339         might_sleep();
 340
 341         list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
 342                 ieee80211_key_free(key);
 343 }
 344
 345 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
 346 {
 347         struct ieee80211_key *key;
 348
 349         ASSERT_RTNL();
 350         might_sleep();
 351
 352         if (WARN_ON(!netif_running(sdata->dev)))
 353                 return;
 354
 355         list_for_each_entry(key, &sdata->key_list, list)
 356                 ieee80211_key_enable_hw_accel(key);
 357 }
 358
 359 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
 360 {
 361         struct ieee80211_key *key;
 362
 363         ASSERT_RTNL();
 364         might_sleep();
 365
 366         list_for_each_entry(key, &sdata->key_list, list)
 367                 ieee80211_key_disable_hw_accel(key);
 368 }