1 /* 2 * hostapd - PMKSA cache for IEEE 802.11i RSN 3 * Copyright (c) 2004-2008, Jouni Malinen <j (at) 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 "utils/includes.h" 10 11 #include "utils/common.h" 12 #include "utils/eloop.h" 13 #include "eapol_auth/eapol_auth_sm.h" 14 #include "eapol_auth/eapol_auth_sm_i.h" 15 #include "sta_info.h" 16 #include "ap_config.h" 17 #include "pmksa_cache_auth.h" 18 19 20 static const int pmksa_cache_max_entries = 1024; 21 static const int dot11RSNAConfigPMKLifetime = 43200; 22 23 struct rsn_pmksa_cache { 24 #define PMKID_HASH_SIZE 128 25 #define PMKID_HASH(pmkid) (unsigned int) ((pmkid)[0] & 0x7f) 26 struct rsn_pmksa_cache_entry *pmkid[PMKID_HASH_SIZE]; 27 struct rsn_pmksa_cache_entry *pmksa; 28 int pmksa_count; 29 30 void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx); 31 void *ctx; 32 }; 33 34 35 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa); 36 37 38 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry) 39 { 40 if (entry == NULL) 41 return; 42 os_free(entry->identity); 43 #ifndef CONFIG_NO_RADIUS 44 radius_free_class(&entry->radius_class); 45 #endif /* CONFIG_NO_RADIUS */ 46 os_free(entry); 47 } 48 49 50 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa, 51 struct rsn_pmksa_cache_entry *entry) 52 { 53 struct rsn_pmksa_cache_entry *pos, *prev; 54 55 pmksa->pmksa_count--; 56 pmksa->free_cb(entry, pmksa->ctx); 57 pos = pmksa->pmkid[PMKID_HASH(entry->pmkid)]; 58 prev = NULL; 59 while (pos) { 60 if (pos == entry) { 61 if (prev != NULL) { 62 prev->hnext = pos->hnext; 63 } else { 64 pmksa->pmkid[PMKID_HASH(entry->pmkid)] = 65 pos->hnext; 66 } 67 break; 68 } 69 prev = pos; 70 pos = pos->hnext; 71 } 72 73 pos = pmksa->pmksa; 74 prev = NULL; 75 while (pos) { 76 if (pos == entry) { 77 if (prev != NULL) 78 prev->next = pos->next; 79 else 80 pmksa->pmksa = pos->next; 81 break; 82 } 83 prev = pos; 84 pos = pos->next; 85 } 86 _pmksa_cache_free_entry(entry); 87 } 88 89 90 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx) 91 { 92 struct rsn_pmksa_cache *pmksa = eloop_ctx; 93 struct os_time now; 94 95 os_get_time(&now); 96 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) { 97 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa; 98 pmksa->pmksa = entry->next; 99 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for " 100 MACSTR, MAC2STR(entry->spa)); 101 pmksa_cache_free_entry(pmksa, entry); 102 } 103 104 pmksa_cache_set_expiration(pmksa); 105 } 106 107 108 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa) 109 { 110 int sec; 111 struct os_time now; 112 113 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL); 114 if (pmksa->pmksa == NULL) 115 return; 116 os_get_time(&now); 117 sec = pmksa->pmksa->expiration - now.sec; 118 if (sec < 0) 119 sec = 0; 120 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL); 121 } 122 123 124 static void pmksa_cache_from_eapol_data(struct rsn_pmksa_cache_entry *entry, 125 struct eapol_state_machine *eapol) 126 { 127 if (eapol == NULL) 128 return; 129 130 if (eapol->identity) { 131 entry->identity = os_malloc(eapol->identity_len); 132 if (entry->identity) { 133 entry->identity_len = eapol->identity_len; 134 os_memcpy(entry->identity, eapol->identity, 135 eapol->identity_len); 136 } 137 } 138 139 #ifndef CONFIG_NO_RADIUS 140 radius_copy_class(&entry->radius_class, &eapol->radius_class); 141 #endif /* CONFIG_NO_RADIUS */ 142 143 entry->eap_type_authsrv = eapol->eap_type_authsrv; 144 entry->vlan_id = ((struct sta_info *) eapol->sta)->vlan_id; 145 } 146 147 148 void pmksa_cache_to_eapol_data(struct rsn_pmksa_cache_entry *entry, 149 struct eapol_state_machine *eapol) 150 { 151 if (entry == NULL || eapol == NULL) 152 return; 153 154 if (entry->identity) { 155 os_free(eapol->identity); 156 eapol->identity = os_malloc(entry->identity_len); 157 if (eapol->identity) { 158 eapol->identity_len = entry->identity_len; 159 os_memcpy(eapol->identity, entry->identity, 160 entry->identity_len); 161 } 162 wpa_hexdump_ascii(MSG_DEBUG, "STA identity from PMKSA", 163 eapol->identity, eapol->identity_len); 164 } 165 166 #ifndef CONFIG_NO_RADIUS 167 radius_free_class(&eapol->radius_class); 168 radius_copy_class(&eapol->radius_class, &entry->radius_class); 169 #endif /* CONFIG_NO_RADIUS */ 170 if (eapol->radius_class.attr) { 171 wpa_printf(MSG_DEBUG, "Copied %lu Class attribute(s) from " 172 "PMKSA", (unsigned long) eapol->radius_class.count); 173 } 174 175 eapol->eap_type_authsrv = entry->eap_type_authsrv; 176 ((struct sta_info *) eapol->sta)->vlan_id = entry->vlan_id; 177 } 178 179 180 static void pmksa_cache_link_entry(struct rsn_pmksa_cache *pmksa, 181 struct rsn_pmksa_cache_entry *entry) 182 { 183 struct rsn_pmksa_cache_entry *pos, *prev; 184 185 /* Add the new entry; order by expiration time */ 186 pos = pmksa->pmksa; 187 prev = NULL; 188 while (pos) { 189 if (pos->expiration > entry->expiration) 190 break; 191 prev = pos; 192 pos = pos->next; 193 } 194 if (prev == NULL) { 195 entry->next = pmksa->pmksa; 196 pmksa->pmksa = entry; 197 } else { 198 entry->next = prev->next; 199 prev->next = entry; 200 } 201 entry->hnext = pmksa->pmkid[PMKID_HASH(entry->pmkid)]; 202 pmksa->pmkid[PMKID_HASH(entry->pmkid)] = entry; 203 204 pmksa->pmksa_count++; 205 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR, 206 MAC2STR(entry->spa)); 207 wpa_hexdump(MSG_DEBUG, "RSN: added PMKID", entry->pmkid, PMKID_LEN); 208 } 209 210 211 /** 212 * pmksa_cache_auth_add - Add a PMKSA cache entry 213 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init() 214 * @pmk: The new pairwise master key 215 * @pmk_len: PMK length in bytes, usually PMK_LEN (32) 216 * @aa: Authenticator address 217 * @spa: Supplicant address 218 * @session_timeout: Session timeout 219 * @eapol: Pointer to EAPOL state machine data 220 * @akmp: WPA_KEY_MGMT_* used in key derivation 221 * Returns: Pointer to the added PMKSA cache entry or %NULL on error 222 * 223 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA 224 * cache. If an old entry is already in the cache for the same Supplicant, 225 * this entry will be replaced with the new entry. PMKID will be calculated 226 * based on the PMK. 227 */ 228 struct rsn_pmksa_cache_entry * 229 pmksa_cache_auth_add(struct rsn_pmksa_cache *pmksa, 230 const u8 *pmk, size_t pmk_len, 231 const u8 *aa, const u8 *spa, int session_timeout, 232 struct eapol_state_machine *eapol, int akmp) 233 { 234 struct rsn_pmksa_cache_entry *entry, *pos; 235 struct os_time now; 236 237 if (pmk_len > PMK_LEN) 238 return NULL; 239 240 entry = os_zalloc(sizeof(*entry)); 241 if (entry == NULL) 242 return NULL; 243 os_memcpy(entry->pmk, pmk, pmk_len); 244 entry->pmk_len = pmk_len; 245 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid, 246 wpa_key_mgmt_sha256(akmp)); 247 os_get_time(&now); 248 entry->expiration = now.sec; 249 if (session_timeout > 0) 250 entry->expiration += session_timeout; 251 else 252 entry->expiration += dot11RSNAConfigPMKLifetime; 253 entry->akmp = akmp; 254 os_memcpy(entry->spa, spa, ETH_ALEN); 255 pmksa_cache_from_eapol_data(entry, eapol); 256 257 /* Replace an old entry for the same STA (if found) with the new entry 258 */ 259 pos = pmksa_cache_auth_get(pmksa, spa, NULL); 260 if (pos) 261 pmksa_cache_free_entry(pmksa, pos); 262 263 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) { 264 /* Remove the oldest entry to make room for the new entry */ 265 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache " 266 "entry (for " MACSTR ") to make room for new one", 267 MAC2STR(pmksa->pmksa->spa)); 268 pmksa_cache_free_entry(pmksa, pmksa->pmksa); 269 } 270 271 pmksa_cache_link_entry(pmksa, entry); 272 273 return entry; 274 } 275 276 277 struct rsn_pmksa_cache_entry * 278 pmksa_cache_add_okc(struct rsn_pmksa_cache *pmksa, 279 const struct rsn_pmksa_cache_entry *old_entry, 280 const u8 *aa, const u8 *pmkid) 281 { 282 struct rsn_pmksa_cache_entry *entry; 283 284 entry = os_zalloc(sizeof(*entry)); 285 if (entry == NULL) 286 return NULL; 287 os_memcpy(entry->pmkid, pmkid, PMKID_LEN); 288 os_memcpy(entry->pmk, old_entry->pmk, old_entry->pmk_len); 289 entry->pmk_len = old_entry->pmk_len; 290 entry->expiration = old_entry->expiration; 291 entry->akmp = old_entry->akmp; 292 os_memcpy(entry->spa, old_entry->spa, ETH_ALEN); 293 entry->opportunistic = 1; 294 if (old_entry->identity) { 295 entry->identity = os_malloc(old_entry->identity_len); 296 if (entry->identity) { 297 entry->identity_len = old_entry->identity_len; 298 os_memcpy(entry->identity, old_entry->identity, 299 old_entry->identity_len); 300 } 301 } 302 #ifndef CONFIG_NO_RADIUS 303 radius_copy_class(&entry->radius_class, &old_entry->radius_class); 304 #endif /* CONFIG_NO_RADIUS */ 305 entry->eap_type_authsrv = old_entry->eap_type_authsrv; 306 entry->vlan_id = old_entry->vlan_id; 307 entry->opportunistic = 1; 308 309 pmksa_cache_link_entry(pmksa, entry); 310 311 return entry; 312 } 313 314 315 /** 316 * pmksa_cache_auth_deinit - Free all entries in PMKSA cache 317 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init() 318 */ 319 void pmksa_cache_auth_deinit(struct rsn_pmksa_cache *pmksa) 320 { 321 struct rsn_pmksa_cache_entry *entry, *prev; 322 int i; 323 324 if (pmksa == NULL) 325 return; 326 327 entry = pmksa->pmksa; 328 while (entry) { 329 prev = entry; 330 entry = entry->next; 331 _pmksa_cache_free_entry(prev); 332 } 333 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL); 334 for (i = 0; i < PMKID_HASH_SIZE; i++) 335 pmksa->pmkid[i] = NULL; 336 os_free(pmksa); 337 } 338 339 340 /** 341 * pmksa_cache_auth_get - Fetch a PMKSA cache entry 342 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init() 343 * @spa: Supplicant address or %NULL to match any 344 * @pmkid: PMKID or %NULL to match any 345 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found 346 */ 347 struct rsn_pmksa_cache_entry * 348 pmksa_cache_auth_get(struct rsn_pmksa_cache *pmksa, 349 const u8 *spa, const u8 *pmkid) 350 { 351 struct rsn_pmksa_cache_entry *entry; 352 353 if (pmkid) 354 entry = pmksa->pmkid[PMKID_HASH(pmkid)]; 355 else 356 entry = pmksa->pmksa; 357 while (entry) { 358 if ((spa == NULL || 359 os_memcmp(entry->spa, spa, ETH_ALEN) == 0) && 360 (pmkid == NULL || 361 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0)) 362 return entry; 363 entry = pmkid ? entry->hnext : entry->next; 364 } 365 return NULL; 366 } 367 368 369 /** 370 * pmksa_cache_get_okc - Fetch a PMKSA cache entry using OKC 371 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init() 372 * @aa: Authenticator address 373 * @spa: Supplicant address 374 * @pmkid: PMKID 375 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found 376 * 377 * Use opportunistic key caching (OKC) to find a PMK for a supplicant. 378 */ 379 struct rsn_pmksa_cache_entry * pmksa_cache_get_okc( 380 struct rsn_pmksa_cache *pmksa, const u8 *aa, const u8 *spa, 381 const u8 *pmkid) 382 { 383 struct rsn_pmksa_cache_entry *entry; 384 u8 new_pmkid[PMKID_LEN]; 385 386 entry = pmksa->pmksa; 387 while (entry) { 388 if (os_memcmp(entry->spa, spa, ETH_ALEN) != 0) 389 continue; 390 rsn_pmkid(entry->pmk, entry->pmk_len, aa, spa, new_pmkid, 391 wpa_key_mgmt_sha256(entry->akmp)); 392 if (os_memcmp(new_pmkid, pmkid, PMKID_LEN) == 0) 393 return entry; 394 entry = entry->next; 395 } 396 return NULL; 397 } 398 399 400 /** 401 * pmksa_cache_auth_init - Initialize PMKSA cache 402 * @free_cb: Callback function to be called when a PMKSA cache entry is freed 403 * @ctx: Context pointer for free_cb function 404 * Returns: Pointer to PMKSA cache data or %NULL on failure 405 */ 406 struct rsn_pmksa_cache * 407 pmksa_cache_auth_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry, 408 void *ctx), void *ctx) 409 { 410 struct rsn_pmksa_cache *pmksa; 411 412 pmksa = os_zalloc(sizeof(*pmksa)); 413 if (pmksa) { 414 pmksa->free_cb = free_cb; 415 pmksa->ctx = ctx; 416 } 417 418 return pmksa; 419 } 420
