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 = key_mtx_dereference(sdata->local, 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 = key_mtx_dereference(sdata->local, 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 && 261 old == key_mtx_dereference(sdata->local, 262 sdata->default_unicast_key); 263 defmultikey = old && 264 old == key_mtx_dereference(sdata->local, 265 sdata->default_multicast_key); 266 defmgmtkey = old && 267 old == key_mtx_dereference(sdata->local, 268 sdata->default_mgmt_key); 269 270 if (defunikey && !new) 271 __ieee80211_set_default_key(sdata, -1, true, false); 272 if (defmultikey && !new) 273 __ieee80211_set_default_key(sdata, -1, false, true); 274 if (defmgmtkey && !new) 275 __ieee80211_set_default_mgmt_key(sdata, -1); 276 277 rcu_assign_pointer(sdata->keys[idx], new); 278 if (defunikey && new) 279 __ieee80211_set_default_key(sdata, new->conf.keyidx, 280 true, false); 281 if (defmultikey && new) 282 __ieee80211_set_default_key(sdata, new->conf.keyidx, 283 false, true); 284 if (defmgmtkey && new) 285 __ieee80211_set_default_mgmt_key(sdata, 286 new->conf.keyidx); 287 } 288 289 if (old) 290 list_del(&old->list); 291 } 292 293 struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len, 294 const u8 *key_data, 295 size_t seq_len, const u8 *seq) 296 { 297 struct ieee80211_key *key; 298 int i, j, err; 299 300 BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS); 301 302 key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL); 303 if (!key) 304 return ERR_PTR(-ENOMEM); 305 306 /* 307 * Default to software encryption; we'll later upload the 308 * key to the hardware if possible. 309 */ 310 key->conf.flags = 0; 311 key->flags = 0; 312 313 key->conf.cipher = cipher; 314 key->conf.keyidx = idx; 315 key->conf.keylen = key_len; 316 switch (cipher) { 317 case WLAN_CIPHER_SUITE_WEP40: 318 case WLAN_CIPHER_SUITE_WEP104: 319 key->conf.iv_len = WEP_IV_LEN; 320 key->conf.icv_len = WEP_ICV_LEN; 321 break; 322 case WLAN_CIPHER_SUITE_TKIP: 323 key->conf.iv_len = TKIP_IV_LEN; 324 key->conf.icv_len = TKIP_ICV_LEN; 325 if (seq) { 326 for (i = 0; i < NUM_RX_DATA_QUEUES; i++) { 327 key->u.tkip.rx[i].iv32 = 328 get_unaligned_le32(&seq[2]); 329 key->u.tkip.rx[i].iv16 = 330 get_unaligned_le16(seq); 331 } 332 } 333 break; 334 case WLAN_CIPHER_SUITE_CCMP: 335 key->conf.iv_len = CCMP_HDR_LEN; 336 key->conf.icv_len = CCMP_MIC_LEN; 337 if (seq) { 338 for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++) 339 for (j = 0; j < CCMP_PN_LEN; j++) 340 key->u.ccmp.rx_pn[i][j] = 341 seq[CCMP_PN_LEN - j - 1]; 342 } 343 /* 344 * Initialize AES key state here as an optimization so that 345 * it does not need to be initialized for every packet. 346 */ 347 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data); 348 if (IS_ERR(key->u.ccmp.tfm)) { 349 err = PTR_ERR(key->u.ccmp.tfm); 350 kfree(key); 351 return ERR_PTR(err); 352 } 353 break; 354 case WLAN_CIPHER_SUITE_AES_CMAC: 355 key->conf.iv_len = 0; 356 key->conf.icv_len = sizeof(struct ieee80211_mmie); 357 if (seq) 358 for (j = 0; j < 6; j++) 359 key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1]; 360 /* 361 * Initialize AES key state here as an optimization so that 362 * it does not need to be initialized for every packet. 363 */ 364 key->u.aes_cmac.tfm = 365 ieee80211_aes_cmac_key_setup(key_data); 366 if (IS_ERR(key->u.aes_cmac.tfm)) { 367 err = PTR_ERR(key->u.aes_cmac.tfm); 368 kfree(key); 369 return ERR_PTR(err); 370 } 371 break; 372 } 373 memcpy(key->conf.key, key_data, key_len); 374 INIT_LIST_HEAD(&key->list); 375 376 return key; 377 } 378 379 static void __ieee80211_key_destroy(struct ieee80211_key *key) 380 { 381 if (!key) 382 return; 383 384 /* 385 * Synchronize so the TX path can no longer be using 386 * this key before we free/remove it. 387 */ 388 synchronize_rcu(); 389 390 if (key->local) 391 ieee80211_key_disable_hw_accel(key); 392 393 if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP) 394 ieee80211_aes_key_free(key->u.ccmp.tfm); 395 if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC) 396 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm); 397 if (key->local) 398 ieee80211_debugfs_key_remove(key); 399 400 kfree(key); 401 } 402 403 int ieee80211_key_link(struct ieee80211_key *key, 404 struct ieee80211_sub_if_data *sdata, 405 struct sta_info *sta) 406 { 407 struct ieee80211_key *old_key; 408 int idx, ret; 409 bool pairwise; 410 411 BUG_ON(!sdata); 412 BUG_ON(!key); 413 414 pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE; 415 idx = key->conf.keyidx; 416 key->local = sdata->local; 417 key->sdata = sdata; 418 key->sta = sta; 419 420 if (sta) { 421 /* 422 * some hardware cannot handle TKIP with QoS, so 423 * we indicate whether QoS could be in use. 424 */ 425 if (test_sta_flags(sta, WLAN_STA_WME)) 426 key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA; 427 } else { 428 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 429 struct sta_info *ap; 430 431 /* 432 * We're getting a sta pointer in, so must be under 433 * appropriate locking for sta_info_get(). 434 */ 435 436 /* same here, the AP could be using QoS */ 437 ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid); 438 if (ap) { 439 if (test_sta_flags(ap, WLAN_STA_WME)) 440 key->conf.flags |= 441 IEEE80211_KEY_FLAG_WMM_STA; 442 } 443 } 444 } 445 446 mutex_lock(&sdata->local->key_mtx); 447 448 if (sta && pairwise) 449 old_key = key_mtx_dereference(sdata->local, sta->ptk); 450 else if (sta) 451 old_key = key_mtx_dereference(sdata->local, sta->gtk[idx]); 452 else 453 old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]); 454 455 __ieee80211_key_replace(sdata, sta, pairwise, old_key, key); 456 __ieee80211_key_destroy(old_key); 457 458 ieee80211_debugfs_key_add(key); 459 460 ret = ieee80211_key_enable_hw_accel(key); 461 462 mutex_unlock(&sdata->local->key_mtx); 463 464 return ret; 465 } 466 467 void __ieee80211_key_free(struct ieee80211_key *key) 468 { 469 if (!key) 470 return; 471 472 /* 473 * Replace key with nothingness if it was ever used. 474 */ 475 if (key->sdata) 476 __ieee80211_key_replace(key->sdata, key->sta, 477 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE, 478 key, NULL); 479 __ieee80211_key_destroy(key); 480 } 481 482 void ieee80211_key_free(struct ieee80211_local *local, 483 struct ieee80211_key *key) 484 { 485 mutex_lock(&local->key_mtx); 486 __ieee80211_key_free(key); 487 mutex_unlock(&local->key_mtx); 488 } 489 490 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata) 491 { 492 struct ieee80211_key *key; 493 494 ASSERT_RTNL(); 495 496 if (WARN_ON(!ieee80211_sdata_running(sdata))) 497 return; 498 499 mutex_lock(&sdata->local->key_mtx); 500 501 list_for_each_entry(key, &sdata->key_list, list) 502 ieee80211_key_enable_hw_accel(key); 503 504 mutex_unlock(&sdata->local->key_mtx); 505 } 506 507 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata) 508 { 509 struct ieee80211_key *key; 510 511 ASSERT_RTNL(); 512 513 mutex_lock(&sdata->local->key_mtx); 514 515 list_for_each_entry(key, &sdata->key_list, list) 516 ieee80211_key_disable_hw_accel(key); 517 518 mutex_unlock(&sdata->local->key_mtx); 519 } 520 521 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata) 522 { 523 struct ieee80211_key *key, *tmp; 524 525 mutex_lock(&sdata->local->key_mtx); 526 527 ieee80211_debugfs_key_remove_mgmt_default(sdata); 528 529 list_for_each_entry_safe(key, tmp, &sdata->key_list, list) 530 __ieee80211_key_free(key); 531 532 ieee80211_debugfs_key_update_default(sdata); 533 534 mutex_unlock(&sdata->local->key_mtx); 535 } 536