1/* 2 * WPA Supplicant - RSN PMKSA cache 3 * Copyright (c) 2004-2009, 2011-2015, Jouni Malinen <j@w1.fi> 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9#include "includes.h" 10 11#include "common.h" 12#include "eloop.h" 13#include "eapol_supp/eapol_supp_sm.h" 14#include "wpa.h" 15#include "wpa_i.h" 16#include "pmksa_cache.h" 17 18#if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA) 19 20static const int pmksa_cache_max_entries = 32; 21 22struct rsn_pmksa_cache { 23 struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */ 24 int pmksa_count; /* number of entries in PMKSA cache */ 25 struct wpa_sm *sm; /* TODO: get rid of this reference(?) */ 26 27 void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx, 28 enum pmksa_free_reason reason); 29 void *ctx; 30}; 31 32 33static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa); 34 35 36static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry) 37{ 38 bin_clear_free(entry, sizeof(*entry)); 39} 40 41 42static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa, 43 struct rsn_pmksa_cache_entry *entry, 44 enum pmksa_free_reason reason) 45{ 46 wpa_sm_remove_pmkid(pmksa->sm, entry->aa, entry->pmkid); 47 pmksa->pmksa_count--; 48 pmksa->free_cb(entry, pmksa->ctx, reason); 49 _pmksa_cache_free_entry(entry); 50} 51 52 53static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx) 54{ 55 struct rsn_pmksa_cache *pmksa = eloop_ctx; 56 struct os_reltime now; 57 58 os_get_reltime(&now); 59 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) { 60 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 61 pmksa->pmksa = entry->next; 62 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for " 63 MACSTR, MAC2STR(entry->aa)); 64 pmksa_cache_free_entry(pmksa, entry, PMKSA_EXPIRE); 65 } 66 67 pmksa_cache_set_expiration(pmksa); 68} 69 70 71static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx) 72{ 73 struct rsn_pmksa_cache *pmksa = eloop_ctx; 74 pmksa->sm->cur_pmksa = NULL; 75 eapol_sm_request_reauth(pmksa->sm->eapol); 76} 77 78 79static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa) 80{ 81 int sec; 82 struct rsn_pmksa_cache_entry *entry; 83 struct os_reltime now; 84 85 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL); 86 eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL); 87 if (pmksa->pmksa == NULL) 88 return; 89 os_get_reltime(&now); 90 sec = pmksa->pmksa->expiration - now.sec; 91 if (sec < 0) 92 sec = 0; 93 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL); 94 95 entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa : 96 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL, NULL); 97 if (entry) { 98 sec = pmksa->pmksa->reauth_time - now.sec; 99 if (sec < 0) 100 sec = 0; 101 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa, 102 NULL); 103 } 104} 105 106 107/** 108 * pmksa_cache_add - Add a PMKSA cache entry 109 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 110 * @pmk: The new pairwise master key 111 * @pmk_len: PMK length in bytes, usually PMK_LEN (32) 112 * @pmkid: Calculated PMKID 113 * @kck: Key confirmation key or %NULL if not yet derived 114 * @kck_len: KCK length in bytes 115 * @aa: Authenticator address 116 * @spa: Supplicant address 117 * @network_ctx: Network configuration context for this PMK 118 * @akmp: WPA_KEY_MGMT_* used in key derivation 119 * Returns: Pointer to the added PMKSA cache entry or %NULL on error 120 * 121 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA 122 * cache. If an old entry is already in the cache for the same Authenticator, 123 * this entry will be replaced with the new entry. PMKID will be calculated 124 * based on the PMK and the driver interface is notified of the new PMKID. 125 */ 126struct rsn_pmksa_cache_entry * 127pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len, 128 const u8 *pmkid, const u8 *kck, size_t kck_len, 129 const u8 *aa, const u8 *spa, void *network_ctx, int akmp) 130{ 131 struct rsn_pmksa_cache_entry *entry, *pos, *prev; 132 struct os_reltime now; 133 134 if (pmk_len > PMK_LEN_MAX) 135 return NULL; 136 137 if (wpa_key_mgmt_suite_b(akmp) && !kck) 138 return NULL; 139 140 entry = os_zalloc(sizeof(*entry)); 141 if (entry == NULL) 142 return NULL; 143 os_memcpy(entry->pmk, pmk, pmk_len); 144 entry->pmk_len = pmk_len; 145 if (pmkid) 146 os_memcpy(entry->pmkid, pmkid, PMKID_LEN); 147 else if (akmp == WPA_KEY_MGMT_IEEE8021X_SUITE_B_192) 148 rsn_pmkid_suite_b_192(kck, kck_len, aa, spa, entry->pmkid); 149 else if (wpa_key_mgmt_suite_b(akmp)) 150 rsn_pmkid_suite_b(kck, kck_len, aa, spa, entry->pmkid); 151 else 152 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid, 153 wpa_key_mgmt_sha256(akmp)); 154 os_get_reltime(&now); 155 entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime; 156 entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime * 157 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100; 158 entry->akmp = akmp; 159 os_memcpy(entry->aa, aa, ETH_ALEN); 160 entry->network_ctx = network_ctx; 161 162 /* Replace an old entry for the same Authenticator (if found) with the 163 * new entry */ 164 pos = pmksa->pmksa; 165 prev = NULL; 166 while (pos) { 167 if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) { 168 if (pos->pmk_len == pmk_len && 169 os_memcmp_const(pos->pmk, pmk, pmk_len) == 0 && 170 os_memcmp_const(pos->pmkid, entry->pmkid, 171 PMKID_LEN) == 0) { 172 wpa_printf(MSG_DEBUG, "WPA: reusing previous " 173 "PMKSA entry"); 174 os_free(entry); 175 return pos; 176 } 177 if (prev == NULL) 178 pmksa->pmksa = pos->next; 179 else 180 prev->next = pos->next; 181 182 /* 183 * If OKC is used, there may be other PMKSA cache 184 * entries based on the same PMK. These needs to be 185 * flushed so that a new entry can be created based on 186 * the new PMK. Only clear other entries if they have a 187 * matching PMK and this PMK has been used successfully 188 * with the current AP, i.e., if opportunistic flag has 189 * been cleared in wpa_supplicant_key_neg_complete(). 190 */ 191 wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for " 192 "the current AP and any PMKSA cache entry " 193 "that was based on the old PMK"); 194 if (!pos->opportunistic) 195 pmksa_cache_flush(pmksa, network_ctx, pos->pmk, 196 pos->pmk_len); 197 pmksa_cache_free_entry(pmksa, pos, PMKSA_REPLACE); 198 break; 199 } 200 prev = pos; 201 pos = pos->next; 202 } 203 204 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) { 205 /* Remove the oldest entry to make room for the new entry */ 206 pos = pmksa->pmksa; 207 208 if (pos == pmksa->sm->cur_pmksa) { 209 /* 210 * Never remove the current PMKSA cache entry, since 211 * it's in use, and removing it triggers a needless 212 * deauthentication. 213 */ 214 pos = pos->next; 215 pmksa->pmksa->next = pos ? pos->next : NULL; 216 } else 217 pmksa->pmksa = pos->next; 218 219 if (pos) { 220 wpa_printf(MSG_DEBUG, "RSN: removed the oldest idle " 221 "PMKSA cache entry (for " MACSTR ") to " 222 "make room for new one", 223 MAC2STR(pos->aa)); 224 pmksa_cache_free_entry(pmksa, pos, PMKSA_FREE); 225 } 226 } 227 228 /* Add the new entry; order by expiration time */ 229 pos = pmksa->pmksa; 230 prev = NULL; 231 while (pos) { 232 if (pos->expiration > entry->expiration) 233 break; 234 prev = pos; 235 pos = pos->next; 236 } 237 if (prev == NULL) { 238 entry->next = pmksa->pmksa; 239 pmksa->pmksa = entry; 240 pmksa_cache_set_expiration(pmksa); 241 } else { 242 entry->next = prev->next; 243 prev->next = entry; 244 } 245 pmksa->pmksa_count++; 246 wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR 247 " network_ctx=%p", MAC2STR(entry->aa), network_ctx); 248 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid); 249 250 return entry; 251} 252 253 254/** 255 * pmksa_cache_flush - Flush PMKSA cache entries for a specific network 256 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 257 * @network_ctx: Network configuration context or %NULL to flush all entries 258 * @pmk: PMK to match for or %NYLL to match all PMKs 259 * @pmk_len: PMK length 260 */ 261void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx, 262 const u8 *pmk, size_t pmk_len) 263{ 264 struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp; 265 int removed = 0; 266 267 entry = pmksa->pmksa; 268 while (entry) { 269 if ((entry->network_ctx == network_ctx || 270 network_ctx == NULL) && 271 (pmk == NULL || 272 (pmk_len == entry->pmk_len && 273 os_memcmp(pmk, entry->pmk, pmk_len) == 0))) { 274 wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry " 275 "for " MACSTR, MAC2STR(entry->aa)); 276 if (prev) 277 prev->next = entry->next; 278 else 279 pmksa->pmksa = entry->next; 280 tmp = entry; 281 entry = entry->next; 282 pmksa_cache_free_entry(pmksa, tmp, PMKSA_FREE); 283 removed++; 284 } else { 285 prev = entry; 286 entry = entry->next; 287 } 288 } 289 if (removed) 290 pmksa_cache_set_expiration(pmksa); 291} 292 293 294/** 295 * pmksa_cache_deinit - Free all entries in PMKSA cache 296 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 297 */ 298void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa) 299{ 300 struct rsn_pmksa_cache_entry *entry, *prev; 301 302 if (pmksa == NULL) 303 return; 304 305 entry = pmksa->pmksa; 306 pmksa->pmksa = NULL; 307 while (entry) { 308 prev = entry; 309 entry = entry->next; 310 os_free(prev); 311 } 312 pmksa_cache_set_expiration(pmksa); 313 os_free(pmksa); 314} 315 316 317/** 318 * pmksa_cache_get - Fetch a PMKSA cache entry 319 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 320 * @aa: Authenticator address or %NULL to match any 321 * @pmkid: PMKID or %NULL to match any 322 * @network_ctx: Network context or %NULL to match any 323 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found 324 */ 325struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa, 326 const u8 *aa, const u8 *pmkid, 327 const void *network_ctx) 328{ 329 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 330 while (entry) { 331 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) && 332 (pmkid == NULL || 333 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) && 334 (network_ctx == NULL || network_ctx == entry->network_ctx)) 335 return entry; 336 entry = entry->next; 337 } 338 return NULL; 339} 340 341 342static struct rsn_pmksa_cache_entry * 343pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa, 344 const struct rsn_pmksa_cache_entry *old_entry, 345 const u8 *aa) 346{ 347 struct rsn_pmksa_cache_entry *new_entry; 348 349 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len, 350 NULL, NULL, 0, 351 aa, pmksa->sm->own_addr, 352 old_entry->network_ctx, old_entry->akmp); 353 if (new_entry == NULL) 354 return NULL; 355 356 /* TODO: reorder entries based on expiration time? */ 357 new_entry->expiration = old_entry->expiration; 358 new_entry->opportunistic = 1; 359 360 return new_entry; 361} 362 363 364/** 365 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry 366 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 367 * @network_ctx: Network configuration context 368 * @aa: Authenticator address for the new AP 369 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available 370 * 371 * Try to create a new PMKSA cache entry opportunistically by guessing that the 372 * new AP is sharing the same PMK as another AP that has the same SSID and has 373 * already an entry in PMKSA cache. 374 */ 375struct rsn_pmksa_cache_entry * 376pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx, 377 const u8 *aa) 378{ 379 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 380 381 wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa)); 382 if (network_ctx == NULL) 383 return NULL; 384 while (entry) { 385 if (entry->network_ctx == network_ctx) { 386 entry = pmksa_cache_clone_entry(pmksa, entry, aa); 387 if (entry) { 388 wpa_printf(MSG_DEBUG, "RSN: added " 389 "opportunistic PMKSA cache entry " 390 "for " MACSTR, MAC2STR(aa)); 391 } 392 return entry; 393 } 394 entry = entry->next; 395 } 396 return NULL; 397} 398 399 400/** 401 * pmksa_cache_get_current - Get the current used PMKSA entry 402 * @sm: Pointer to WPA state machine data from wpa_sm_init() 403 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available 404 */ 405struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm) 406{ 407 if (sm == NULL) 408 return NULL; 409 return sm->cur_pmksa; 410} 411 412 413/** 414 * pmksa_cache_clear_current - Clear the current PMKSA entry selection 415 * @sm: Pointer to WPA state machine data from wpa_sm_init() 416 */ 417void pmksa_cache_clear_current(struct wpa_sm *sm) 418{ 419 if (sm == NULL) 420 return; 421 sm->cur_pmksa = NULL; 422} 423 424 425/** 426 * pmksa_cache_set_current - Set the current PMKSA entry selection 427 * @sm: Pointer to WPA state machine data from wpa_sm_init() 428 * @pmkid: PMKID for selecting PMKSA or %NULL if not used 429 * @bssid: BSSID for PMKSA or %NULL if not used 430 * @network_ctx: Network configuration context 431 * @try_opportunistic: Whether to allow opportunistic PMKSA caching 432 * Returns: 0 if PMKSA was found or -1 if no matching entry was found 433 */ 434int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid, 435 const u8 *bssid, void *network_ctx, 436 int try_opportunistic) 437{ 438 struct rsn_pmksa_cache *pmksa = sm->pmksa; 439 wpa_printf(MSG_DEBUG, "RSN: PMKSA cache search - network_ctx=%p " 440 "try_opportunistic=%d", network_ctx, try_opportunistic); 441 if (pmkid) 442 wpa_hexdump(MSG_DEBUG, "RSN: Search for PMKID", 443 pmkid, PMKID_LEN); 444 if (bssid) 445 wpa_printf(MSG_DEBUG, "RSN: Search for BSSID " MACSTR, 446 MAC2STR(bssid)); 447 448 sm->cur_pmksa = NULL; 449 if (pmkid) 450 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid, 451 network_ctx); 452 if (sm->cur_pmksa == NULL && bssid) 453 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL, 454 network_ctx); 455 if (sm->cur_pmksa == NULL && try_opportunistic && bssid) 456 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa, 457 network_ctx, 458 bssid); 459 if (sm->cur_pmksa) { 460 wpa_hexdump(MSG_DEBUG, "RSN: PMKSA cache entry found - PMKID", 461 sm->cur_pmksa->pmkid, PMKID_LEN); 462 return 0; 463 } 464 wpa_printf(MSG_DEBUG, "RSN: No PMKSA cache entry found"); 465 return -1; 466} 467 468 469/** 470 * pmksa_cache_list - Dump text list of entries in PMKSA cache 471 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 472 * @buf: Buffer for the list 473 * @len: Length of the buffer 474 * Returns: number of bytes written to buffer 475 * 476 * This function is used to generate a text format representation of the 477 * current PMKSA cache contents for the ctrl_iface PMKSA command. 478 */ 479int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len) 480{ 481 int i, ret; 482 char *pos = buf; 483 struct rsn_pmksa_cache_entry *entry; 484 struct os_reltime now; 485 486 os_get_reltime(&now); 487 ret = os_snprintf(pos, buf + len - pos, 488 "Index / AA / PMKID / expiration (in seconds) / " 489 "opportunistic\n"); 490 if (os_snprintf_error(buf + len - pos, ret)) 491 return pos - buf; 492 pos += ret; 493 i = 0; 494 entry = pmksa->pmksa; 495 while (entry) { 496 i++; 497 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ", 498 i, MAC2STR(entry->aa)); 499 if (os_snprintf_error(buf + len - pos, ret)) 500 return pos - buf; 501 pos += ret; 502 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid, 503 PMKID_LEN); 504 ret = os_snprintf(pos, buf + len - pos, " %d %d\n", 505 (int) (entry->expiration - now.sec), 506 entry->opportunistic); 507 if (os_snprintf_error(buf + len - pos, ret)) 508 return pos - buf; 509 pos += ret; 510 entry = entry->next; 511 } 512 return pos - buf; 513} 514 515 516/** 517 * pmksa_cache_init - Initialize PMKSA cache 518 * @free_cb: Callback function to be called when a PMKSA cache entry is freed 519 * @ctx: Context pointer for free_cb function 520 * @sm: Pointer to WPA state machine data from wpa_sm_init() 521 * Returns: Pointer to PMKSA cache data or %NULL on failure 522 */ 523struct rsn_pmksa_cache * 524pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry, 525 void *ctx, enum pmksa_free_reason reason), 526 void *ctx, struct wpa_sm *sm) 527{ 528 struct rsn_pmksa_cache *pmksa; 529 530 pmksa = os_zalloc(sizeof(*pmksa)); 531 if (pmksa) { 532 pmksa->free_cb = free_cb; 533 pmksa->ctx = ctx; 534 pmksa->sm = sm; 535 } 536 537 return pmksa; 538} 539 540#endif /* IEEE8021X_EAPOL */ 541