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 2007-2008 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 <linux/slab.h> 18 #include <net/mac80211.h> 19 #include "ieee80211_i.h" 20 #include "driver-ops.h" 21 #include "debugfs_key.h" 22 #include "aes_ccm.h" 23 #include "aes_cmac.h" 24 25 26 /** 27 * DOC: Key handling basics 28 * 29 * Key handling in mac80211 is done based on per-interface (sub_if_data) 30 * keys and per-station keys. Since each station belongs to an interface, 31 * each station key also belongs to that interface. 32 * 33 * Hardware acceleration is done on a best-effort basis for algorithms 34 * that are implemented in software, for each key the hardware is asked 35 * to enable that key for offloading but if it cannot do that the key is 36 * simply kept for software encryption (unless it is for an algorithm 37 * that isn't implemented in software). 38 * There is currently no way of knowing whether a key is handled in SW 39 * or HW except by looking into debugfs. 40 * 41 * All key management is internally protected by a mutex. Within all 42 * other parts of mac80211, key references are, just as STA structure 43 * references, protected by RCU. Note, however, that some things are 44 * unprotected, namely the key->sta dereferences within the hardware 45 * acceleration functions. This means that sta_info_destroy() must 46 * remove the key which waits for an RCU grace period. 47 */ 48 49 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; 50 51 static void assert_key_lock(struct ieee80211_local *local) 52 { 53 lockdep_assert_held(&local->key_mtx); 54 } 55 56 static struct ieee80211_sta *get_sta_for_key(struct ieee80211_key *key) 57 { 58 if (key->sta) 59 return &key->sta->sta; 60 61 return NULL; 62 } 63 64 static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key) 65 { 66 struct ieee80211_sub_if_data *sdata; 67 struct ieee80211_sta *sta; 68 int ret; 69 70 might_sleep(); 71 72 if (!key->local->ops->set_key) 73 goto out_unsupported; 74 75 assert_key_lock(key->local); 76 77 sta = get_sta_for_key(key); 78 79 /* 80 * If this is a per-STA GTK, check if it 81 * is supported; if not, return. 82 */ 83 if (sta && !(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE) && 84 !(key->local->hw.flags & IEEE80211_HW_SUPPORTS_PER_STA_GTK)) 85 goto out_unsupported; 86 87 sdata = key->sdata; 88 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) { 89 /* 90 * The driver doesn't know anything about VLAN interfaces. 91 * Hence, don't send GTKs for VLAN interfaces to the driver. 92 */ 93 if (!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE)) 94 goto out_unsupported; 95 sdata = container_of(sdata->bss, 96 struct ieee80211_sub_if_data, 97 u.ap); 98 } 99 100 ret = drv_set_key(key->local, SET_KEY, sdata, sta, &key->conf); 101 102 if (!ret) { 103 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE; 104 return 0; 105 } 106 107 if (ret != -ENOSPC && ret != -EOPNOTSUPP) 108 wiphy_err(key->local->hw.wiphy, 109 "failed to set key (%d, %pM) to hardware (%d)\n", 110 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret); 111 112 out_unsupported: 113 switch (key->conf.cipher) { 114 case WLAN_CIPHER_SUITE_WEP40: 115 case WLAN_CIPHER_SUITE_WEP104: 116 case WLAN_CIPHER_SUITE_TKIP: 117 case WLAN_CIPHER_SUITE_CCMP: 118 case WLAN_CIPHER_SUITE_AES_CMAC: 119 /* all of these we can do in software */ 120 return 0; 121 default: 122 return -EINVAL; 123 } 124 } 125 126 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key) 127 { 128 struct ieee80211_sub_if_data *sdata; 129 struct ieee80211_sta *sta; 130 int ret; 131 132 might_sleep(); 133 134 if (!key || !key->local->ops->set_key) 135 return; 136 137 assert_key_lock(key->local); 138 139 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)) 140 return; 141 142 sta = get_sta_for_key(key); 143 sdata = key->sdata; 144 145 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) 146 sdata = container_of(sdata->bss, 147 struct ieee80211_sub_if_data, 148 u.ap); 149 150 ret = drv_set_key(key->local, DISABLE_KEY, sdata, 151 sta, &key->conf); 152 153 if (ret) 154 wiphy_err(key->local->hw.wiphy, 155 "failed to remove key (%d, %pM) from hardware (%d)\n", 156 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret); 157 158 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE; 159 } 160 161 void ieee80211_key_removed(struct ieee80211_key_conf *key_conf) 162 { 163 struct ieee80211_key *key; 164 165 key = container_of(key_conf, struct ieee80211_key, conf); 166 167 might_sleep(); 168 assert_key_lock(key->local); 169 170 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE; 171 172 /* 173 * Flush TX path to avoid attempts to use this key 174 * after this function returns. Until then, drivers 175 * must be prepared to handle the key. 176 */ 177 synchronize_rcu(); 178 } 179 EXPORT_SYMBOL_GPL(ieee80211_key_removed); 180 181 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, 182 int idx, bool uni, bool multi) 183 { 184 struct ieee80211_key *key = NULL; 185 186 assert_key_lock(sdata->local); 187 188 if (idx >= 0 && idx < NUM_DEFAULT_KEYS) 189 key = sdata->keys[idx]; 190 191 if (uni) 192 rcu_assign_pointer(sdata->default_unicast_key, key); 193 if (multi) 194 rcu_assign_pointer(sdata->default_multicast_key, key); 195 196 ieee80211_debugfs_key_update_default(sdata); 197 } 198 199 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx, 200 bool uni, bool multi) 201 { 202 mutex_lock(&sdata->local->key_mtx); 203 __ieee80211_set_default_key(sdata, idx, uni, multi); 204 mutex_unlock(&sdata->local->key_mtx); 205 } 206 207 static void 208 __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx) 209 { 210 struct ieee80211_key *key = NULL; 211 212 assert_key_lock(sdata->local); 213 214 if (idx >= NUM_DEFAULT_KEYS && 215 idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS) 216 key = sdata->keys[idx]; 217 218 rcu_assign_pointer(sdata->default_mgmt_key, key); 219 220 ieee80211_debugfs_key_update_default(sdata); 221 } 222 223 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, 224 int idx) 225 { 226 mutex_lock(&sdata->local->key_mtx); 227 __ieee80211_set_default_mgmt_key(sdata, idx); 228 mutex_unlock(&sdata->local->key_mtx); 229 } 230 231 232 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata, 233 struct sta_info *sta, 234 bool pairwise, 235 struct ieee80211_key *old, 236 struct ieee80211_key *new) 237 { 238 int idx; 239 bool defunikey, defmultikey, defmgmtkey; 240 241 if (new) 242 list_add(&new->list, &sdata->key_list); 243 244 if (sta && pairwise) { 245 rcu_assign_pointer(sta->ptk, new); 246 } else if (sta) { 247 if (old) 248 idx = old->conf.keyidx; 249 else 250 idx = new->conf.keyidx; 251 rcu_assign_pointer(sta->gtk[idx], new); 252 } else { 253 WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx); 254 255 if (old) 256 idx = old->conf.keyidx; 257 else 258 idx = new->conf.keyidx; 259 260 defunikey = old && sdata->default_unicast_key == old; 261 defmultikey = old && sdata->default_multicast_key == old; 262 defmgmtkey = old && sdata->default_mgmt_key == old; 263 264 if (defunikey && !new) 265 __ieee80211_set_default_key(sdata, -1, true, false); 266 if (defmultikey && !new) 267 __ieee80211_set_default_key(sdata, -1, false, true); 268 if (defmgmtkey && !new) 269 __ieee80211_set_default_mgmt_key(sdata, -1); 270 271 rcu_assign_pointer(sdata->keys[idx], new); 272 if (defunikey && new) 273 __ieee80211_set_default_key(sdata, new->conf.keyidx, 274 true, false); 275 if (defmultikey && new) 276 __ieee80211_set_default_key(sdata, new->conf.keyidx, 277 false, true); 278 if (defmgmtkey && new) 279 __ieee80211_set_default_mgmt_key(sdata, 280 new->conf.keyidx); 281 } 282 283 if (old) 284 list_del(&old->list); 285 } 286 287 struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len, 288 const u8 *key_data, 289 size_t seq_len, const u8 *seq) 290 { 291 struct ieee80211_key *key; 292 int i, j, err; 293 294 BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS); 295 296 key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL); 297 if (!key) 298 return ERR_PTR(-ENOMEM); 299 300 /* 301 * Default to software encryption; we'll later upload the 302 * key to the hardware if possible. 303 */ 304 key->conf.flags = 0; 305 key->flags = 0; 306 307 key->conf.cipher = cipher; 308 key->conf.keyidx = idx; 309 key->conf.keylen = key_len; 310 switch (cipher) { 311 case WLAN_CIPHER_SUITE_WEP40: 312 case WLAN_CIPHER_SUITE_WEP104: 313 key->conf.iv_len = WEP_IV_LEN; 314 key->conf.icv_len = WEP_ICV_LEN; 315 break; 316 case WLAN_CIPHER_SUITE_TKIP: 317 key->conf.iv_len = TKIP_IV_LEN; 318 key->conf.icv_len = TKIP_ICV_LEN; 319 if (seq) { 320 for (i = 0; i < NUM_RX_DATA_QUEUES; i++) { 321 key->u.tkip.rx[i].iv32 = 322 get_unaligned_le32(&seq[2]); 323 key->u.tkip.rx[i].iv16 = 324 get_unaligned_le16(seq); 325 } 326 } 327 break; 328 case WLAN_CIPHER_SUITE_CCMP: 329 key->conf.iv_len = CCMP_HDR_LEN; 330 key->conf.icv_len = CCMP_MIC_LEN; 331 if (seq) { 332 for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++) 333 for (j = 0; j < CCMP_PN_LEN; j++) 334 key->u.ccmp.rx_pn[i][j] = 335 seq[CCMP_PN_LEN - j - 1]; 336 } 337 /* 338 * Initialize AES key state here as an optimization so that 339 * it does not need to be initialized for every packet. 340 */ 341 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data); 342 if (IS_ERR(key->u.ccmp.tfm)) { 343 err = PTR_ERR(key->u.ccmp.tfm); 344 kfree(key); 345 key = ERR_PTR(err); 346 } 347 break; 348 case WLAN_CIPHER_SUITE_AES_CMAC: 349 key->conf.iv_len = 0; 350 key->conf.icv_len = sizeof(struct ieee80211_mmie); 351 if (seq) 352 for (j = 0; j < 6; j++) 353 key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1]; 354 /* 355 * Initialize AES key state here as an optimization so that 356 * it does not need to be initialized for every packet. 357 */ 358 key->u.aes_cmac.tfm = 359 ieee80211_aes_cmac_key_setup(key_data); 360 if (IS_ERR(key->u.aes_cmac.tfm)) { 361 err = PTR_ERR(key->u.aes_cmac.tfm); 362 kfree(key); 363 key = ERR_PTR(err); 364 } 365 break; 366 } 367 memcpy(key->conf.key, key_data, key_len); 368 INIT_LIST_HEAD(&key->list); 369 370 return key; 371 } 372 373 static void __ieee80211_key_destroy(struct ieee80211_key *key) 374 { 375 if (!key) 376 return; 377 378 /* 379 * Synchronize so the TX path can no longer be using 380 * this key before we free/remove it. 381 */ 382 synchronize_rcu(); 383 384 if (key->local) 385 ieee80211_key_disable_hw_accel(key); 386 387 if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP) 388 ieee80211_aes_key_free(key->u.ccmp.tfm); 389 if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC) 390 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm); 391 if (key->local) 392 ieee80211_debugfs_key_remove(key); 393 394 kfree(key); 395 } 396 397 int ieee80211_key_link(struct ieee80211_key *key, 398 struct ieee80211_sub_if_data *sdata, 399 struct sta_info *sta) 400 { 401 struct ieee80211_key *old_key; 402 int idx, ret; 403 bool pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE; 404 405 BUG_ON(!sdata); 406 BUG_ON(!key); 407 408 idx = key->conf.keyidx; 409 key->local = sdata->local; 410 key->sdata = sdata; 411 key->sta = sta; 412 413 if (sta) { 414 /* 415 * some hardware cannot handle TKIP with QoS, so 416 * we indicate whether QoS could be in use. 417 */ 418 if (test_sta_flags(sta, WLAN_STA_WME)) 419 key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA; 420 } else { 421 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 422 struct sta_info *ap; 423 424 /* 425 * We're getting a sta pointer in, so must be under 426 * appropriate locking for sta_info_get(). 427 */ 428 429 /* same here, the AP could be using QoS */ 430 ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid); 431 if (ap) { 432 if (test_sta_flags(ap, WLAN_STA_WME)) 433 key->conf.flags |= 434 IEEE80211_KEY_FLAG_WMM_STA; 435 } 436 } 437 } 438 439 mutex_lock(&sdata->local->key_mtx); 440 441 if (sta && pairwise) 442 old_key = sta->ptk; 443 else if (sta) 444 old_key = sta->gtk[idx]; 445 else 446 old_key = sdata->keys[idx]; 447 448 __ieee80211_key_replace(sdata, sta, pairwise, old_key, key); 449 __ieee80211_key_destroy(old_key); 450 451 ieee80211_debugfs_key_add(key); 452 453 ret = ieee80211_key_enable_hw_accel(key); 454 455 mutex_unlock(&sdata->local->key_mtx); 456 457 return ret; 458 } 459 460 static void __ieee80211_key_free(struct ieee80211_key *key) 461 { 462 /* 463 * Replace key with nothingness if it was ever used. 464 */ 465 if (key->sdata) 466 __ieee80211_key_replace(key->sdata, key->sta, 467 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE, 468 key, NULL); 469 __ieee80211_key_destroy(key); 470 } 471 472 void ieee80211_key_free(struct ieee80211_local *local, 473 struct ieee80211_key *key) 474 { 475 if (!key) 476 return; 477 478 mutex_lock(&local->key_mtx); 479 __ieee80211_key_free(key); 480 mutex_unlock(&local->key_mtx); 481 } 482 483 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata) 484 { 485 struct ieee80211_key *key; 486 487 ASSERT_RTNL(); 488 489 if (WARN_ON(!ieee80211_sdata_running(sdata))) 490 return; 491 492 mutex_lock(&sdata->local->key_mtx); 493 494 list_for_each_entry(key, &sdata->key_list, list) 495 ieee80211_key_enable_hw_accel(key); 496 497 mutex_unlock(&sdata->local->key_mtx); 498 } 499 500 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata) 501 { 502 struct ieee80211_key *key; 503 504 ASSERT_RTNL(); 505 506 mutex_lock(&sdata->local->key_mtx); 507 508 list_for_each_entry(key, &sdata->key_list, list) 509 ieee80211_key_disable_hw_accel(key); 510 511 mutex_unlock(&sdata->local->key_mtx); 512 } 513 514 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata) 515 { 516 struct ieee80211_key *key, *tmp; 517 518 mutex_lock(&sdata->local->key_mtx); 519 520 ieee80211_debugfs_key_remove_mgmt_default(sdata); 521 522 list_for_each_entry_safe(key, tmp, &sdata->key_list, list) 523 __ieee80211_key_free(key); 524 525 ieee80211_debugfs_key_update_default(sdata); 526 527 mutex_unlock(&sdata->local->key_mtx); 528 } 529