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; 104 105 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) || 106 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV))) 107 key->local->crypto_tx_tailroom_needed_cnt--; 108 109 return 0; 110 } 111 112 if (ret != -ENOSPC && ret != -EOPNOTSUPP) 113 wiphy_err(key->local->hw.wiphy, 114 "failed to set key (%d, %pM) to hardware (%d)\n", 115 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret); 116 117 out_unsupported: 118 switch (key->conf.cipher) { 119 case WLAN_CIPHER_SUITE_WEP40: 120 case WLAN_CIPHER_SUITE_WEP104: 121 case WLAN_CIPHER_SUITE_TKIP: 122 case WLAN_CIPHER_SUITE_CCMP: 123 case WLAN_CIPHER_SUITE_AES_CMAC: 124 /* all of these we can do in software */ 125 return 0; 126 default: 127 return -EINVAL; 128 } 129 } 130 131 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key) 132 { 133 struct ieee80211_sub_if_data *sdata; 134 struct ieee80211_sta *sta; 135 int ret; 136 137 might_sleep(); 138 139 if (!key || !key->local->ops->set_key) 140 return; 141 142 assert_key_lock(key->local); 143 144 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)) 145 return; 146 147 sta = get_sta_for_key(key); 148 sdata = key->sdata; 149 150 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) 151 sdata = container_of(sdata->bss, 152 struct ieee80211_sub_if_data, 153 u.ap); 154 155 ret = drv_set_key(key->local, DISABLE_KEY, sdata, 156 sta, &key->conf); 157 158 if (ret) 159 wiphy_err(key->local->hw.wiphy, 160 "failed to remove key (%d, %pM) from hardware (%d)\n", 161 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret); 162 163 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE; 164 165 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) || 166 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV))) 167 key->local->crypto_tx_tailroom_needed_cnt++; 168 } 169 170 void ieee80211_key_removed(struct ieee80211_key_conf *key_conf) 171 { 172 struct ieee80211_key *key; 173 174 key = container_of(key_conf, struct ieee80211_key, conf); 175 176 might_sleep(); 177 assert_key_lock(key->local); 178 179 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE; 180 181 /* 182 * Flush TX path to avoid attempts to use this key 183 * after this function returns. Until then, drivers 184 * must be prepared to handle the key. 185 */ 186 synchronize_rcu(); 187 } 188 EXPORT_SYMBOL_GPL(ieee80211_key_removed); 189 190 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, 191 int idx, bool uni, bool multi) 192 { 193 struct ieee80211_key *key = NULL; 194 195 assert_key_lock(sdata->local); 196 197 if (idx >= 0 && idx < NUM_DEFAULT_KEYS) 198 key = key_mtx_dereference(sdata->local, sdata->keys[idx]); 199 200 if (uni) 201 rcu_assign_pointer(sdata->default_unicast_key, key); 202 if (multi) 203 rcu_assign_pointer(sdata->default_multicast_key, key); 204 205 ieee80211_debugfs_key_update_default(sdata); 206 } 207 208 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx, 209 bool uni, bool multi) 210 { 211 mutex_lock(&sdata->local->key_mtx); 212 __ieee80211_set_default_key(sdata, idx, uni, multi); 213 mutex_unlock(&sdata->local->key_mtx); 214 } 215 216 static void 217 __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx) 218 { 219 struct ieee80211_key *key = NULL; 220 221 assert_key_lock(sdata->local); 222 223 if (idx >= NUM_DEFAULT_KEYS && 224 idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS) 225 key = key_mtx_dereference(sdata->local, sdata->keys[idx]); 226 227 rcu_assign_pointer(sdata->default_mgmt_key, key); 228 229 ieee80211_debugfs_key_update_default(sdata); 230 } 231 232 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, 233 int idx) 234 { 235 mutex_lock(&sdata->local->key_mtx); 236 __ieee80211_set_default_mgmt_key(sdata, idx); 237 mutex_unlock(&sdata->local->key_mtx); 238 } 239 240 241 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata, 242 struct sta_info *sta, 243 bool pairwise, 244 struct ieee80211_key *old, 245 struct ieee80211_key *new) 246 { 247 int idx; 248 bool defunikey, defmultikey, defmgmtkey; 249 250 if (new) 251 list_add(&new->list, &sdata->key_list); 252 253 if (sta && pairwise) { 254 rcu_assign_pointer(sta->ptk, new); 255 } else if (sta) { 256 if (old) 257 idx = old->conf.keyidx; 258 else 259 idx = new->conf.keyidx; 260 rcu_assign_pointer(sta->gtk[idx], new); 261 } else { 262 WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx); 263 264 if (old) 265 idx = old->conf.keyidx; 266 else 267 idx = new->conf.keyidx; 268 269 defunikey = old && 270 old == key_mtx_dereference(sdata->local, 271 sdata->default_unicast_key); 272 defmultikey = old && 273 old == key_mtx_dereference(sdata->local, 274 sdata->default_multicast_key); 275 defmgmtkey = old && 276 old == key_mtx_dereference(sdata->local, 277 sdata->default_mgmt_key); 278 279 if (defunikey && !new) 280 __ieee80211_set_default_key(sdata, -1, true, false); 281 if (defmultikey && !new) 282 __ieee80211_set_default_key(sdata, -1, false, true); 283 if (defmgmtkey && !new) 284 __ieee80211_set_default_mgmt_key(sdata, -1); 285 286 rcu_assign_pointer(sdata->keys[idx], new); 287 if (defunikey && new) 288 __ieee80211_set_default_key(sdata, new->conf.keyidx, 289 true, false); 290 if (defmultikey && new) 291 __ieee80211_set_default_key(sdata, new->conf.keyidx, 292 false, true); 293 if (defmgmtkey && new) 294 __ieee80211_set_default_mgmt_key(sdata, 295 new->conf.keyidx); 296 } 297 298 if (old) 299 list_del(&old->list); 300 } 301 302 struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len, 303 const u8 *key_data, 304 size_t seq_len, const u8 *seq) 305 { 306 struct ieee80211_key *key; 307 int i, j, err; 308 309 BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS); 310 311 key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL); 312 if (!key) 313 return ERR_PTR(-ENOMEM); 314 315 /* 316 * Default to software encryption; we'll later upload the 317 * key to the hardware if possible. 318 */ 319 key->conf.flags = 0; 320 key->flags = 0; 321 322 key->conf.cipher = cipher; 323 key->conf.keyidx = idx; 324 key->conf.keylen = key_len; 325 switch (cipher) { 326 case WLAN_CIPHER_SUITE_WEP40: 327 case WLAN_CIPHER_SUITE_WEP104: 328 key->conf.iv_len = WEP_IV_LEN; 329 key->conf.icv_len = WEP_ICV_LEN; 330 break; 331 case WLAN_CIPHER_SUITE_TKIP: 332 key->conf.iv_len = TKIP_IV_LEN; 333 key->conf.icv_len = TKIP_ICV_LEN; 334 if (seq) { 335 for (i = 0; i < NUM_RX_DATA_QUEUES; i++) { 336 key->u.tkip.rx[i].iv32 = 337 get_unaligned_le32(&seq[2]); 338 key->u.tkip.rx[i].iv16 = 339 get_unaligned_le16(seq); 340 } 341 } 342 break; 343 case WLAN_CIPHER_SUITE_CCMP: 344 key->conf.iv_len = CCMP_HDR_LEN; 345 key->conf.icv_len = CCMP_MIC_LEN; 346 if (seq) { 347 for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++) 348 for (j = 0; j < CCMP_PN_LEN; j++) 349 key->u.ccmp.rx_pn[i][j] = 350 seq[CCMP_PN_LEN - j - 1]; 351 } 352 /* 353 * Initialize AES key state here as an optimization so that 354 * it does not need to be initialized for every packet. 355 */ 356 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data); 357 if (IS_ERR(key->u.ccmp.tfm)) { 358 err = PTR_ERR(key->u.ccmp.tfm); 359 kfree(key); 360 return ERR_PTR(err); 361 } 362 break; 363 case WLAN_CIPHER_SUITE_AES_CMAC: 364 key->conf.iv_len = 0; 365 key->conf.icv_len = sizeof(struct ieee80211_mmie); 366 if (seq) 367 for (j = 0; j < 6; j++) 368 key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1]; 369 /* 370 * Initialize AES key state here as an optimization so that 371 * it does not need to be initialized for every packet. 372 */ 373 key->u.aes_cmac.tfm = 374 ieee80211_aes_cmac_key_setup(key_data); 375 if (IS_ERR(key->u.aes_cmac.tfm)) { 376 err = PTR_ERR(key->u.aes_cmac.tfm); 377 kfree(key); 378 return ERR_PTR(err); 379 } 380 break; 381 } 382 memcpy(key->conf.key, key_data, key_len); 383 INIT_LIST_HEAD(&key->list); 384 385 return key; 386 } 387 388 static void __ieee80211_key_destroy(struct ieee80211_key *key) 389 { 390 if (!key) 391 return; 392 393 /* 394 * Synchronize so the TX path can no longer be using 395 * this key before we free/remove it. 396 */ 397 synchronize_rcu(); 398 399 if (key->local) 400 ieee80211_key_disable_hw_accel(key); 401 402 if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP) 403 ieee80211_aes_key_free(key->u.ccmp.tfm); 404 if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC) 405 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm); 406 if (key->local) { 407 ieee80211_debugfs_key_remove(key); 408 key->local->crypto_tx_tailroom_needed_cnt--; 409 } 410 411 kfree(key); 412 } 413 414 int ieee80211_key_link(struct ieee80211_key *key, 415 struct ieee80211_sub_if_data *sdata, 416 struct sta_info *sta) 417 { 418 struct ieee80211_key *old_key; 419 int idx, ret; 420 bool pairwise; 421 422 BUG_ON(!sdata); 423 BUG_ON(!key); 424 425 pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE; 426 idx = key->conf.keyidx; 427 key->local = sdata->local; 428 key->sdata = sdata; 429 key->sta = sta; 430 431 if (sta) { 432 /* 433 * some hardware cannot handle TKIP with QoS, so 434 * we indicate whether QoS could be in use. 435 */ 436 if (test_sta_flags(sta, WLAN_STA_WME)) 437 key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA; 438 } else { 439 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 440 struct sta_info *ap; 441 442 /* 443 * We're getting a sta pointer in, so must be under 444 * appropriate locking for sta_info_get(). 445 */ 446 447 /* same here, the AP could be using QoS */ 448 ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid); 449 if (ap) { 450 if (test_sta_flags(ap, WLAN_STA_WME)) 451 key->conf.flags |= 452 IEEE80211_KEY_FLAG_WMM_STA; 453 } 454 } 455 } 456 457 mutex_lock(&sdata->local->key_mtx); 458 459 if (sta && pairwise) 460 old_key = key_mtx_dereference(sdata->local, sta->ptk); 461 else if (sta) 462 old_key = key_mtx_dereference(sdata->local, sta->gtk[idx]); 463 else 464 old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]); 465 466 __ieee80211_key_replace(sdata, sta, pairwise, old_key, key); 467 __ieee80211_key_destroy(old_key); 468 469 ieee80211_debugfs_key_add(key); 470 471 key->local->crypto_tx_tailroom_needed_cnt++; 472 473 ret = ieee80211_key_enable_hw_accel(key); 474 475 mutex_unlock(&sdata->local->key_mtx); 476 477 return ret; 478 } 479 480 void __ieee80211_key_free(struct ieee80211_key *key) 481 { 482 if (!key) 483 return; 484 485 /* 486 * Replace key with nothingness if it was ever used. 487 */ 488 if (key->sdata) 489 __ieee80211_key_replace(key->sdata, key->sta, 490 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE, 491 key, NULL); 492 __ieee80211_key_destroy(key); 493 } 494 495 void ieee80211_key_free(struct ieee80211_local *local, 496 struct ieee80211_key *key) 497 { 498 mutex_lock(&local->key_mtx); 499 __ieee80211_key_free(key); 500 mutex_unlock(&local->key_mtx); 501 } 502 503 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata) 504 { 505 struct ieee80211_key *key; 506 507 ASSERT_RTNL(); 508 509 if (WARN_ON(!ieee80211_sdata_running(sdata))) 510 return; 511 512 mutex_lock(&sdata->local->key_mtx); 513 514 sdata->local->crypto_tx_tailroom_needed_cnt = 0; 515 516 list_for_each_entry(key, &sdata->key_list, list) { 517 sdata->local->crypto_tx_tailroom_needed_cnt++; 518 ieee80211_key_enable_hw_accel(key); 519 } 520 521 mutex_unlock(&sdata->local->key_mtx); 522 } 523 524 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata) 525 { 526 struct ieee80211_key *key; 527 528 ASSERT_RTNL(); 529 530 mutex_lock(&sdata->local->key_mtx); 531 532 list_for_each_entry(key, &sdata->key_list, list) 533 ieee80211_key_disable_hw_accel(key); 534 535 mutex_unlock(&sdata->local->key_mtx); 536 } 537 538 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata) 539 { 540 struct ieee80211_key *key, *tmp; 541 542 mutex_lock(&sdata->local->key_mtx); 543 544 ieee80211_debugfs_key_remove_mgmt_default(sdata); 545 546 list_for_each_entry_safe(key, tmp, &sdata->key_list, list) 547 __ieee80211_key_free(key); 548 549 ieee80211_debugfs_key_update_default(sdata); 550 551 mutex_unlock(&sdata->local->key_mtx); 552 } 553