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00001 /* 00002 * WPA Supplicant - RSN PMKSA cache 00003 * Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi> 00004 * 00005 * This program is free software; you can redistribute it and/or modify 00006 * it under the terms of the GNU General Public License version 2 as 00007 * published by the Free Software Foundation. 00008 * 00009 * Alternatively, this software may be distributed under the terms of BSD 00010 * license. 00011 * 00012 * See README and COPYING for more details. 00013 */ 00014 00015 #include "includes.h" 00016 00017 #include "common.h" 00018 #include "eloop.h" 00019 #include "eapol_supp/eapol_supp_sm.h" 00020 #include "wpa.h" 00021 #include "wpa_i.h" 00022 #include "pmksa_cache.h" 00023 00024 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2) 00025 00026 static const int pmksa_cache_max_entries = 32; 00027 00028 struct rsn_pmksa_cache { 00029 struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */ 00030 int pmksa_count; /* number of entries in PMKSA cache */ 00031 struct wpa_sm *sm; /* TODO: get rid of this reference(?) */ 00032 00033 void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx, 00034 int replace); 00035 void *ctx; 00036 }; 00037 00038 00039 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa); 00040 00041 00042 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry) 00043 { 00044 os_free(entry); 00045 } 00046 00047 00048 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa, 00049 struct rsn_pmksa_cache_entry *entry, 00050 int replace) 00051 { 00052 pmksa->pmksa_count--; 00053 pmksa->free_cb(entry, pmksa->ctx, replace); 00054 _pmksa_cache_free_entry(entry); 00055 } 00056 00057 00058 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx) 00059 { 00060 struct rsn_pmksa_cache *pmksa = eloop_ctx; 00061 struct os_time now; 00062 00063 os_get_time(&now); 00064 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) { 00065 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 00066 pmksa->pmksa = entry->next; 00067 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for " 00068 MACSTR, MAC2STR(entry->aa)); 00069 pmksa_cache_free_entry(pmksa, entry, 0); 00070 } 00071 00072 pmksa_cache_set_expiration(pmksa); 00073 } 00074 00075 00076 static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx) 00077 { 00078 struct rsn_pmksa_cache *pmksa = eloop_ctx; 00079 pmksa->sm->cur_pmksa = NULL; 00080 eapol_sm_request_reauth(pmksa->sm->eapol); 00081 } 00082 00083 00084 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa) 00085 { 00086 int sec; 00087 struct rsn_pmksa_cache_entry *entry; 00088 struct os_time now; 00089 00090 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL); 00091 eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL); 00092 if (pmksa->pmksa == NULL) 00093 return; 00094 os_get_time(&now); 00095 sec = pmksa->pmksa->expiration - now.sec; 00096 if (sec < 0) 00097 sec = 0; 00098 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL); 00099 00100 entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa : 00101 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL); 00102 if (entry) { 00103 sec = pmksa->pmksa->reauth_time - now.sec; 00104 if (sec < 0) 00105 sec = 0; 00106 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa, 00107 NULL); 00108 } 00109 } 00110 00111 00128 struct rsn_pmksa_cache_entry * 00129 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len, 00130 const u8 *aa, const u8 *spa, void *network_ctx, int akmp) 00131 { 00132 struct rsn_pmksa_cache_entry *entry, *pos, *prev; 00133 struct os_time now; 00134 00135 if (pmk_len > PMK_LEN) 00136 return NULL; 00137 00138 entry = os_zalloc(sizeof(*entry)); 00139 if (entry == NULL) 00140 return NULL; 00141 os_memcpy(entry->pmk, pmk, pmk_len); 00142 entry->pmk_len = pmk_len; 00143 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid, 00144 wpa_key_mgmt_sha256(akmp)); 00145 os_get_time(&now); 00146 entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime; 00147 entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime * 00148 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100; 00149 entry->akmp = akmp; 00150 os_memcpy(entry->aa, aa, ETH_ALEN); 00151 entry->network_ctx = network_ctx; 00152 00153 /* Replace an old entry for the same Authenticator (if found) with the 00154 * new entry */ 00155 pos = pmksa->pmksa; 00156 prev = NULL; 00157 while (pos) { 00158 if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) { 00159 if (pos->pmk_len == pmk_len && 00160 os_memcmp(pos->pmk, pmk, pmk_len) == 0 && 00161 os_memcmp(pos->pmkid, entry->pmkid, PMKID_LEN) == 00162 0) { 00163 wpa_printf(MSG_DEBUG, "WPA: reusing previous " 00164 "PMKSA entry"); 00165 os_free(entry); 00166 return pos; 00167 } 00168 if (prev == NULL) 00169 pmksa->pmksa = pos->next; 00170 else 00171 prev->next = pos->next; 00172 if (pos == pmksa->sm->cur_pmksa) { 00173 /* We are about to replace the current PMKSA 00174 * cache entry. This happens when the PMKSA 00175 * caching attempt fails, so we don't want to 00176 * force pmksa_cache_free_entry() to disconnect 00177 * at this point. Let's just make sure the old 00178 * PMKSA cache entry will not be used in the 00179 * future. 00180 */ 00181 wpa_printf(MSG_DEBUG, "RSN: replacing current " 00182 "PMKSA entry"); 00183 pmksa->sm->cur_pmksa = NULL; 00184 } 00185 wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for " 00186 "the current AP"); 00187 pmksa_cache_free_entry(pmksa, pos, 1); 00188 break; 00189 } 00190 prev = pos; 00191 pos = pos->next; 00192 } 00193 00194 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) { 00195 /* Remove the oldest entry to make room for the new entry */ 00196 pos = pmksa->pmksa; 00197 pmksa->pmksa = pos->next; 00198 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache " 00199 "entry (for " MACSTR ") to make room for new one", 00200 MAC2STR(pos->aa)); 00201 wpa_sm_remove_pmkid(pmksa->sm, pos->aa, pos->pmkid); 00202 pmksa_cache_free_entry(pmksa, pos, 0); 00203 } 00204 00205 /* Add the new entry; order by expiration time */ 00206 pos = pmksa->pmksa; 00207 prev = NULL; 00208 while (pos) { 00209 if (pos->expiration > entry->expiration) 00210 break; 00211 prev = pos; 00212 pos = pos->next; 00213 } 00214 if (prev == NULL) { 00215 entry->next = pmksa->pmksa; 00216 pmksa->pmksa = entry; 00217 pmksa_cache_set_expiration(pmksa); 00218 } else { 00219 entry->next = prev->next; 00220 prev->next = entry; 00221 } 00222 pmksa->pmksa_count++; 00223 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR, 00224 MAC2STR(entry->aa)); 00225 wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid); 00226 00227 return entry; 00228 } 00229 00230 00235 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa) 00236 { 00237 struct rsn_pmksa_cache_entry *entry, *prev; 00238 00239 if (pmksa == NULL) 00240 return; 00241 00242 entry = pmksa->pmksa; 00243 pmksa->pmksa = NULL; 00244 while (entry) { 00245 prev = entry; 00246 entry = entry->next; 00247 os_free(prev); 00248 } 00249 pmksa_cache_set_expiration(pmksa); 00250 os_free(pmksa); 00251 } 00252 00253 00261 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa, 00262 const u8 *aa, const u8 *pmkid) 00263 { 00264 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 00265 while (entry) { 00266 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) && 00267 (pmkid == NULL || 00268 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0)) 00269 return entry; 00270 entry = entry->next; 00271 } 00272 return NULL; 00273 } 00274 00275 00282 void pmksa_cache_notify_reconfig(struct rsn_pmksa_cache *pmksa) 00283 { 00284 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 00285 while (entry) { 00286 entry->network_ctx = NULL; 00287 entry = entry->next; 00288 } 00289 } 00290 00291 00292 static struct rsn_pmksa_cache_entry * 00293 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa, 00294 const struct rsn_pmksa_cache_entry *old_entry, 00295 const u8 *aa) 00296 { 00297 struct rsn_pmksa_cache_entry *new_entry; 00298 00299 new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len, 00300 aa, pmksa->sm->own_addr, 00301 old_entry->network_ctx, old_entry->akmp); 00302 if (new_entry == NULL) 00303 return NULL; 00304 00305 /* TODO: reorder entries based on expiration time? */ 00306 new_entry->expiration = old_entry->expiration; 00307 new_entry->opportunistic = 1; 00308 00309 return new_entry; 00310 } 00311 00312 00324 struct rsn_pmksa_cache_entry * 00325 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx, 00326 const u8 *aa) 00327 { 00328 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 00329 00330 if (network_ctx == NULL) 00331 return NULL; 00332 while (entry) { 00333 if (entry->network_ctx == network_ctx) { 00334 entry = pmksa_cache_clone_entry(pmksa, entry, aa); 00335 if (entry) { 00336 wpa_printf(MSG_DEBUG, "RSN: added " 00337 "opportunistic PMKSA cache entry " 00338 "for " MACSTR, MAC2STR(aa)); 00339 } 00340 return entry; 00341 } 00342 entry = entry->next; 00343 } 00344 return NULL; 00345 } 00346 00347 00353 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm) 00354 { 00355 if (sm == NULL) 00356 return NULL; 00357 return sm->cur_pmksa; 00358 } 00359 00360 00365 void pmksa_cache_clear_current(struct wpa_sm *sm) 00366 { 00367 if (sm == NULL) 00368 return; 00369 sm->cur_pmksa = NULL; 00370 } 00371 00372 00382 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid, 00383 const u8 *bssid, void *network_ctx, 00384 int try_opportunistic) 00385 { 00386 struct rsn_pmksa_cache *pmksa = sm->pmksa; 00387 sm->cur_pmksa = NULL; 00388 if (pmkid) 00389 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid); 00390 if (sm->cur_pmksa == NULL && bssid) 00391 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL); 00392 if (sm->cur_pmksa == NULL && try_opportunistic && bssid) 00393 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa, 00394 network_ctx, 00395 bssid); 00396 if (sm->cur_pmksa) { 00397 wpa_hexdump(MSG_DEBUG, "RSN: PMKID", 00398 sm->cur_pmksa->pmkid, PMKID_LEN); 00399 return 0; 00400 } 00401 return -1; 00402 } 00403 00404 00415 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len) 00416 { 00417 int i, ret; 00418 char *pos = buf; 00419 struct rsn_pmksa_cache_entry *entry; 00420 struct os_time now; 00421 00422 os_get_time(&now); 00423 ret = os_snprintf(pos, buf + len - pos, 00424 "Index / AA / PMKID / expiration (in seconds) / " 00425 "opportunistic\n"); 00426 if (ret < 0 || ret >= buf + len - pos) 00427 return pos - buf; 00428 pos += ret; 00429 i = 0; 00430 entry = pmksa->pmksa; 00431 while (entry) { 00432 i++; 00433 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ", 00434 i, MAC2STR(entry->aa)); 00435 if (ret < 0 || ret >= buf + len - pos) 00436 return pos - buf; 00437 pos += ret; 00438 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid, 00439 PMKID_LEN); 00440 ret = os_snprintf(pos, buf + len - pos, " %d %d\n", 00441 (int) (entry->expiration - now.sec), 00442 entry->opportunistic); 00443 if (ret < 0 || ret >= buf + len - pos) 00444 return pos - buf; 00445 pos += ret; 00446 entry = entry->next; 00447 } 00448 return pos - buf; 00449 } 00450 00451 00459 struct rsn_pmksa_cache * 00460 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry, 00461 void *ctx, int replace), 00462 void *ctx, struct wpa_sm *sm) 00463 { 00464 struct rsn_pmksa_cache *pmksa; 00465 00466 pmksa = os_zalloc(sizeof(*pmksa)); 00467 if (pmksa) { 00468 pmksa->free_cb = free_cb; 00469 pmksa->ctx = ctx; 00470 pmksa->sm = sm; 00471 } 00472 00473 return pmksa; 00474 } 00475 00476 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */