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->network_ctx, entry->aa, 47 entry->pmkid); 48 pmksa->pmksa_count--; 49 pmksa->free_cb(entry, pmksa->ctx, reason); 50 _pmksa_cache_free_entry(entry); 51} 52 53 54static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx) 55{ 56 struct rsn_pmksa_cache *pmksa = eloop_ctx; 57 struct os_reltime now; 58 59 os_get_reltime(&now); 60 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) { 61 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 62 pmksa->pmksa = entry->next; 63 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for " 64 MACSTR, MAC2STR(entry->aa)); 65 pmksa_cache_free_entry(pmksa, entry, PMKSA_EXPIRE); 66 } 67 68 pmksa_cache_set_expiration(pmksa); 69} 70 71 72static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx) 73{ 74 struct rsn_pmksa_cache *pmksa = eloop_ctx; 75 pmksa->sm->cur_pmksa = NULL; 76 eapol_sm_request_reauth(pmksa->sm->eapol); 77} 78 79 80static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa) 81{ 82 int sec; 83 struct rsn_pmksa_cache_entry *entry; 84 struct os_reltime now; 85 86 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL); 87 eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL); 88 if (pmksa->pmksa == NULL) 89 return; 90 os_get_reltime(&now); 91 sec = pmksa->pmksa->expiration - now.sec; 92 if (sec < 0) 93 sec = 0; 94 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL); 95 96 entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa : 97 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL, NULL); 98 if (entry) { 99 sec = pmksa->pmksa->reauth_time - now.sec; 100 if (sec < 0) 101 sec = 0; 102 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa, 103 NULL); 104 } 105} 106 107 108/** 109 * pmksa_cache_add - Add a PMKSA cache entry 110 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 111 * @pmk: The new pairwise master key 112 * @pmk_len: PMK length in bytes, usually PMK_LEN (32) 113 * @pmkid: Calculated PMKID 114 * @kck: Key confirmation key or %NULL if not yet derived 115 * @kck_len: KCK length in bytes 116 * @aa: Authenticator address 117 * @spa: Supplicant address 118 * @network_ctx: Network configuration context for this PMK 119 * @akmp: WPA_KEY_MGMT_* used in key derivation 120 * Returns: Pointer to the added PMKSA cache entry or %NULL on error 121 * 122 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA 123 * cache. If an old entry is already in the cache for the same Authenticator, 124 * this entry will be replaced with the new entry. PMKID will be calculated 125 * based on the PMK and the driver interface is notified of the new PMKID. 126 */ 127struct rsn_pmksa_cache_entry * 128pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len, 129 const u8 *pmkid, const u8 *kck, size_t kck_len, 130 const u8 *aa, const u8 *spa, void *network_ctx, int akmp) 131{ 132 struct rsn_pmksa_cache_entry *entry; 133 struct os_reltime now; 134 135 if (pmk_len > PMK_LEN_MAX) 136 return NULL; 137 138 if (wpa_key_mgmt_suite_b(akmp) && !kck) 139 return NULL; 140 141 entry = os_zalloc(sizeof(*entry)); 142 if (entry == NULL) 143 return NULL; 144 os_memcpy(entry->pmk, pmk, pmk_len); 145 entry->pmk_len = pmk_len; 146 if (pmkid) 147 os_memcpy(entry->pmkid, pmkid, PMKID_LEN); 148 else if (akmp == WPA_KEY_MGMT_IEEE8021X_SUITE_B_192) 149 rsn_pmkid_suite_b_192(kck, kck_len, aa, spa, entry->pmkid); 150 else if (wpa_key_mgmt_suite_b(akmp)) 151 rsn_pmkid_suite_b(kck, kck_len, aa, spa, entry->pmkid); 152 else 153 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid, 154 wpa_key_mgmt_sha256(akmp)); 155 os_get_reltime(&now); 156 entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime; 157 entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime * 158 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100; 159 entry->akmp = akmp; 160 os_memcpy(entry->aa, aa, ETH_ALEN); 161 entry->network_ctx = network_ctx; 162 163 return pmksa_cache_add_entry(pmksa, entry); 164} 165 166 167struct rsn_pmksa_cache_entry * 168pmksa_cache_add_entry(struct rsn_pmksa_cache *pmksa, 169 struct rsn_pmksa_cache_entry *entry) 170{ 171 struct rsn_pmksa_cache_entry *pos, *prev; 172 173 /* Replace an old entry for the same Authenticator (if found) with the 174 * new entry */ 175 pos = pmksa->pmksa; 176 prev = NULL; 177 while (pos) { 178 if (os_memcmp(entry->aa, pos->aa, ETH_ALEN) == 0) { 179 if (pos->pmk_len == entry->pmk_len && 180 os_memcmp_const(pos->pmk, entry->pmk, 181 entry->pmk_len) == 0 && 182 os_memcmp_const(pos->pmkid, entry->pmkid, 183 PMKID_LEN) == 0) { 184 wpa_printf(MSG_DEBUG, "WPA: reusing previous " 185 "PMKSA entry"); 186 os_free(entry); 187 return pos; 188 } 189 if (prev == NULL) 190 pmksa->pmksa = pos->next; 191 else 192 prev->next = pos->next; 193 194 /* 195 * If OKC is used, there may be other PMKSA cache 196 * entries based on the same PMK. These needs to be 197 * flushed so that a new entry can be created based on 198 * the new PMK. Only clear other entries if they have a 199 * matching PMK and this PMK has been used successfully 200 * with the current AP, i.e., if opportunistic flag has 201 * been cleared in wpa_supplicant_key_neg_complete(). 202 */ 203 wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for " 204 "the current AP and any PMKSA cache entry " 205 "that was based on the old PMK"); 206 if (!pos->opportunistic) 207 pmksa_cache_flush(pmksa, entry->network_ctx, 208 pos->pmk, pos->pmk_len); 209 pmksa_cache_free_entry(pmksa, pos, PMKSA_REPLACE); 210 break; 211 } 212 prev = pos; 213 pos = pos->next; 214 } 215 216 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) { 217 /* Remove the oldest entry to make room for the new entry */ 218 pos = pmksa->pmksa; 219 220 if (pos == pmksa->sm->cur_pmksa) { 221 /* 222 * Never remove the current PMKSA cache entry, since 223 * it's in use, and removing it triggers a needless 224 * deauthentication. 225 */ 226 pos = pos->next; 227 pmksa->pmksa->next = pos ? pos->next : NULL; 228 } else 229 pmksa->pmksa = pos->next; 230 231 if (pos) { 232 wpa_printf(MSG_DEBUG, "RSN: removed the oldest idle " 233 "PMKSA cache entry (for " MACSTR ") to " 234 "make room for new one", 235 MAC2STR(pos->aa)); 236 pmksa_cache_free_entry(pmksa, pos, PMKSA_FREE); 237 } 238 } 239 240 /* Add the new entry; order by expiration time */ 241 pos = pmksa->pmksa; 242 prev = NULL; 243 while (pos) { 244 if (pos->expiration > entry->expiration) 245 break; 246 prev = pos; 247 pos = pos->next; 248 } 249 if (prev == NULL) { 250 entry->next = pmksa->pmksa; 251 pmksa->pmksa = entry; 252 pmksa_cache_set_expiration(pmksa); 253 } else { 254 entry->next = prev->next; 255 prev->next = entry; 256 } 257 pmksa->pmksa_count++; 258 wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR 259 " network_ctx=%p", MAC2STR(entry->aa), entry->network_ctx); 260 wpa_sm_add_pmkid(pmksa->sm, entry->network_ctx, entry->aa, 261 entry->pmkid); 262 263 return entry; 264} 265 266 267/** 268 * pmksa_cache_flush - Flush PMKSA cache entries for a specific network 269 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 270 * @network_ctx: Network configuration context or %NULL to flush all entries 271 * @pmk: PMK to match for or %NYLL to match all PMKs 272 * @pmk_len: PMK length 273 */ 274void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx, 275 const u8 *pmk, size_t pmk_len) 276{ 277 struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp; 278 int removed = 0; 279 280 entry = pmksa->pmksa; 281 while (entry) { 282 if ((entry->network_ctx == network_ctx || 283 network_ctx == NULL) && 284 (pmk == NULL || 285 (pmk_len == entry->pmk_len && 286 os_memcmp(pmk, entry->pmk, pmk_len) == 0))) { 287 wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry " 288 "for " MACSTR, MAC2STR(entry->aa)); 289 if (prev) 290 prev->next = entry->next; 291 else 292 pmksa->pmksa = entry->next; 293 tmp = entry; 294 entry = entry->next; 295 pmksa_cache_free_entry(pmksa, tmp, PMKSA_FREE); 296 removed++; 297 } else { 298 prev = entry; 299 entry = entry->next; 300 } 301 } 302 if (removed) 303 pmksa_cache_set_expiration(pmksa); 304} 305 306 307/** 308 * pmksa_cache_deinit - Free all entries in PMKSA cache 309 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 310 */ 311void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa) 312{ 313 struct rsn_pmksa_cache_entry *entry, *prev; 314 315 if (pmksa == NULL) 316 return; 317 318 entry = pmksa->pmksa; 319 pmksa->pmksa = NULL; 320 while (entry) { 321 prev = entry; 322 entry = entry->next; 323 os_free(prev); 324 } 325 pmksa_cache_set_expiration(pmksa); 326 os_free(pmksa); 327} 328 329 330/** 331 * pmksa_cache_get - Fetch a PMKSA cache entry 332 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 333 * @aa: Authenticator address or %NULL to match any 334 * @pmkid: PMKID or %NULL to match any 335 * @network_ctx: Network context or %NULL to match any 336 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found 337 */ 338struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa, 339 const u8 *aa, const u8 *pmkid, 340 const void *network_ctx) 341{ 342 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 343 while (entry) { 344 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) && 345 (pmkid == NULL || 346 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) && 347 (network_ctx == NULL || network_ctx == entry->network_ctx)) 348 return entry; 349 entry = entry->next; 350 } 351 return NULL; 352} 353 354 355static struct rsn_pmksa_cache_entry * 356pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa, 357 const struct rsn_pmksa_cache_entry *old_entry, 358 const u8 *aa) 359{ 360 struct rsn_pmksa_cache_entry *new_entry; 361 362 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len, 363 NULL, NULL, 0, 364 aa, pmksa->sm->own_addr, 365 old_entry->network_ctx, old_entry->akmp); 366 if (new_entry == NULL) 367 return NULL; 368 369 /* TODO: reorder entries based on expiration time? */ 370 new_entry->expiration = old_entry->expiration; 371 new_entry->opportunistic = 1; 372 373 return new_entry; 374} 375 376 377/** 378 * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry 379 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 380 * @network_ctx: Network configuration context 381 * @aa: Authenticator address for the new AP 382 * Returns: Pointer to a new PMKSA cache entry or %NULL if not available 383 * 384 * Try to create a new PMKSA cache entry opportunistically by guessing that the 385 * new AP is sharing the same PMK as another AP that has the same SSID and has 386 * already an entry in PMKSA cache. 387 */ 388struct rsn_pmksa_cache_entry * 389pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx, 390 const u8 *aa) 391{ 392 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 393 394 wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa)); 395 if (network_ctx == NULL) 396 return NULL; 397 while (entry) { 398 if (entry->network_ctx == network_ctx) { 399 entry = pmksa_cache_clone_entry(pmksa, entry, aa); 400 if (entry) { 401 wpa_printf(MSG_DEBUG, "RSN: added " 402 "opportunistic PMKSA cache entry " 403 "for " MACSTR, MAC2STR(aa)); 404 } 405 return entry; 406 } 407 entry = entry->next; 408 } 409 return NULL; 410} 411 412 413/** 414 * pmksa_cache_get_current - Get the current used PMKSA entry 415 * @sm: Pointer to WPA state machine data from wpa_sm_init() 416 * Returns: Pointer to the current PMKSA cache entry or %NULL if not available 417 */ 418struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm) 419{ 420 if (sm == NULL) 421 return NULL; 422 return sm->cur_pmksa; 423} 424 425 426/** 427 * pmksa_cache_clear_current - Clear the current PMKSA entry selection 428 * @sm: Pointer to WPA state machine data from wpa_sm_init() 429 */ 430void pmksa_cache_clear_current(struct wpa_sm *sm) 431{ 432 if (sm == NULL) 433 return; 434 sm->cur_pmksa = NULL; 435} 436 437 438/** 439 * pmksa_cache_set_current - Set the current PMKSA entry selection 440 * @sm: Pointer to WPA state machine data from wpa_sm_init() 441 * @pmkid: PMKID for selecting PMKSA or %NULL if not used 442 * @bssid: BSSID for PMKSA or %NULL if not used 443 * @network_ctx: Network configuration context 444 * @try_opportunistic: Whether to allow opportunistic PMKSA caching 445 * Returns: 0 if PMKSA was found or -1 if no matching entry was found 446 */ 447int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid, 448 const u8 *bssid, void *network_ctx, 449 int try_opportunistic) 450{ 451 struct rsn_pmksa_cache *pmksa = sm->pmksa; 452 wpa_printf(MSG_DEBUG, "RSN: PMKSA cache search - network_ctx=%p " 453 "try_opportunistic=%d", network_ctx, try_opportunistic); 454 if (pmkid) 455 wpa_hexdump(MSG_DEBUG, "RSN: Search for PMKID", 456 pmkid, PMKID_LEN); 457 if (bssid) 458 wpa_printf(MSG_DEBUG, "RSN: Search for BSSID " MACSTR, 459 MAC2STR(bssid)); 460 461 sm->cur_pmksa = NULL; 462 if (pmkid) 463 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid, 464 network_ctx); 465 if (sm->cur_pmksa == NULL && bssid) 466 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL, 467 network_ctx); 468 if (sm->cur_pmksa == NULL && try_opportunistic && bssid) 469 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa, 470 network_ctx, 471 bssid); 472 if (sm->cur_pmksa) { 473 wpa_hexdump(MSG_DEBUG, "RSN: PMKSA cache entry found - PMKID", 474 sm->cur_pmksa->pmkid, PMKID_LEN); 475 return 0; 476 } 477 wpa_printf(MSG_DEBUG, "RSN: No PMKSA cache entry found"); 478 return -1; 479} 480 481 482/** 483 * pmksa_cache_list - Dump text list of entries in PMKSA cache 484 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init() 485 * @buf: Buffer for the list 486 * @len: Length of the buffer 487 * Returns: number of bytes written to buffer 488 * 489 * This function is used to generate a text format representation of the 490 * current PMKSA cache contents for the ctrl_iface PMKSA command. 491 */ 492int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len) 493{ 494 int i, ret; 495 char *pos = buf; 496 struct rsn_pmksa_cache_entry *entry; 497 struct os_reltime now; 498 499 os_get_reltime(&now); 500 ret = os_snprintf(pos, buf + len - pos, 501 "Index / AA / PMKID / expiration (in seconds) / " 502 "opportunistic\n"); 503 if (os_snprintf_error(buf + len - pos, ret)) 504 return pos - buf; 505 pos += ret; 506 i = 0; 507 entry = pmksa->pmksa; 508 while (entry) { 509 i++; 510 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ", 511 i, MAC2STR(entry->aa)); 512 if (os_snprintf_error(buf + len - pos, ret)) 513 return pos - buf; 514 pos += ret; 515 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid, 516 PMKID_LEN); 517 ret = os_snprintf(pos, buf + len - pos, " %d %d\n", 518 (int) (entry->expiration - now.sec), 519 entry->opportunistic); 520 if (os_snprintf_error(buf + len - pos, ret)) 521 return pos - buf; 522 pos += ret; 523 entry = entry->next; 524 } 525 return pos - buf; 526} 527 528 529struct rsn_pmksa_cache_entry * pmksa_cache_head(struct rsn_pmksa_cache *pmksa) 530{ 531 return pmksa->pmksa; 532} 533 534 535/** 536 * pmksa_cache_init - Initialize PMKSA cache 537 * @free_cb: Callback function to be called when a PMKSA cache entry is freed 538 * @ctx: Context pointer for free_cb function 539 * @sm: Pointer to WPA state machine data from wpa_sm_init() 540 * Returns: Pointer to PMKSA cache data or %NULL on failure 541 */ 542struct rsn_pmksa_cache * 543pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry, 544 void *ctx, enum pmksa_free_reason reason), 545 void *ctx, struct wpa_sm *sm) 546{ 547 struct rsn_pmksa_cache *pmksa; 548 549 pmksa = os_zalloc(sizeof(*pmksa)); 550 if (pmksa) { 551 pmksa->free_cb = free_cb; 552 pmksa->ctx = ctx; 553 pmksa->sm = sm; 554 } 555 556 return pmksa; 557} 558 559#endif /* IEEE8021X_EAPOL */ 560