1 /* 2 * hostapd - PMKSA cache for IEEE 802.11i RSN 3 * Copyright (c) 2004-2008, 2012, 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 os_free(entry->identity); 41 wpabuf_free(entry->cui); 42 #ifndef CONFIG_NO_RADIUS 43 radius_free_class(&entry->radius_class); 44 #endif /* CONFIG_NO_RADIUS */ 45 bin_clear_free(entry, sizeof(*entry)); 46 } 47 48 49 void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa, 50 struct rsn_pmksa_cache_entry *entry) 51 { 52 struct rsn_pmksa_cache_entry *pos, *prev; 53 unsigned int hash; 54 55 pmksa->pmksa_count--; 56 pmksa->free_cb(entry, pmksa->ctx); 57 58 /* unlink from hash list */ 59 hash = PMKID_HASH(entry->pmkid); 60 pos = pmksa->pmkid[hash]; 61 prev = NULL; 62 while (pos) { 63 if (pos == entry) { 64 if (prev != NULL) 65 prev->hnext = entry->hnext; 66 else 67 pmksa->pmkid[hash] = entry->hnext; 68 break; 69 } 70 prev = pos; 71 pos = pos->hnext; 72 } 73 74 /* unlink from entry list */ 75 pos = pmksa->pmksa; 76 prev = NULL; 77 while (pos) { 78 if (pos == entry) { 79 if (prev != NULL) 80 prev->next = entry->next; 81 else 82 pmksa->pmksa = entry->next; 83 break; 84 } 85 prev = pos; 86 pos = pos->next; 87 } 88 89 _pmksa_cache_free_entry(entry); 90 } 91 92 93 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx) 94 { 95 struct rsn_pmksa_cache *pmksa = eloop_ctx; 96 struct os_reltime now; 97 98 os_get_reltime(&now); 99 while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) { 100 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for " 101 MACSTR, MAC2STR(pmksa->pmksa->spa)); 102 pmksa_cache_free_entry(pmksa, pmksa->pmksa); 103 } 104 105 pmksa_cache_set_expiration(pmksa); 106 } 107 108 109 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa) 110 { 111 int sec; 112 struct os_reltime now; 113 114 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL); 115 if (pmksa->pmksa == NULL) 116 return; 117 os_get_reltime(&now); 118 sec = pmksa->pmksa->expiration - now.sec; 119 if (sec < 0) 120 sec = 0; 121 eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL); 122 } 123 124 125 static void pmksa_cache_from_eapol_data(struct rsn_pmksa_cache_entry *entry, 126 struct eapol_state_machine *eapol) 127 { 128 if (eapol == NULL) 129 return; 130 131 if (eapol->identity) { 132 entry->identity = os_malloc(eapol->identity_len); 133 if (entry->identity) { 134 entry->identity_len = eapol->identity_len; 135 os_memcpy(entry->identity, eapol->identity, 136 eapol->identity_len); 137 } 138 } 139 140 if (eapol->radius_cui) 141 entry->cui = wpabuf_dup(eapol->radius_cui); 142 143 #ifndef CONFIG_NO_RADIUS 144 radius_copy_class(&entry->radius_class, &eapol->radius_class); 145 #endif /* CONFIG_NO_RADIUS */ 146 147 entry->eap_type_authsrv = eapol->eap_type_authsrv; 148 entry->vlan_id = ((struct sta_info *) eapol->sta)->vlan_id; 149 } 150 151 152 void pmksa_cache_to_eapol_data(struct rsn_pmksa_cache_entry *entry, 153 struct eapol_state_machine *eapol) 154 { 155 if (entry == NULL || eapol == NULL) 156 return; 157 158 if (entry->identity) { 159 os_free(eapol->identity); 160 eapol->identity = os_malloc(entry->identity_len); 161 if (eapol->identity) { 162 eapol->identity_len = entry->identity_len; 163 os_memcpy(eapol->identity, entry->identity, 164 entry->identity_len); 165 } 166 wpa_hexdump_ascii(MSG_DEBUG, "STA identity from PMKSA", 167 eapol->identity, eapol->identity_len); 168 } 169 170 if (entry->cui) { 171 wpabuf_free(eapol->radius_cui); 172 eapol->radius_cui = wpabuf_dup(entry->cui); 173 } 174 175 #ifndef CONFIG_NO_RADIUS 176 radius_free_class(&eapol->radius_class); 177 radius_copy_class(&eapol->radius_class, &entry->radius_class); 178 #endif /* CONFIG_NO_RADIUS */ 179 if (eapol->radius_class.attr) { 180 wpa_printf(MSG_DEBUG, "Copied %lu Class attribute(s) from " 181 "PMKSA", (unsigned long) eapol->radius_class.count); 182 } 183 184 eapol->eap_type_authsrv = entry->eap_type_authsrv; 185 ((struct sta_info *) eapol->sta)->vlan_id = entry->vlan_id; 186 } 187 188 189 static void pmksa_cache_link_entry(struct rsn_pmksa_cache *pmksa, 190 struct rsn_pmksa_cache_entry *entry) 191 { 192 struct rsn_pmksa_cache_entry *pos, *prev; 193 int hash; 194 195 /* Add the new entry; order by expiration time */ 196 pos = pmksa->pmksa; 197 prev = NULL; 198 while (pos) { 199 if (pos->expiration > entry->expiration) 200 break; 201 prev = pos; 202 pos = pos->next; 203 } 204 if (prev == NULL) { 205 entry->next = pmksa->pmksa; 206 pmksa->pmksa = entry; 207 } else { 208 entry->next = prev->next; 209 prev->next = entry; 210 } 211 212 hash = PMKID_HASH(entry->pmkid); 213 entry->hnext = pmksa->pmkid[hash]; 214 pmksa->pmkid[hash] = entry; 215 216 pmksa->pmksa_count++; 217 if (prev == NULL) 218 pmksa_cache_set_expiration(pmksa); 219 wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR, 220 MAC2STR(entry->spa)); 221 wpa_hexdump(MSG_DEBUG, "RSN: added PMKID", entry->pmkid, PMKID_LEN); 222 } 223 224 225 /** 226 * pmksa_cache_auth_add - Add a PMKSA cache entry 227 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init() 228 * @pmk: The new pairwise master key 229 * @pmk_len: PMK length in bytes, usually PMK_LEN (32) 230 * @aa: Authenticator address 231 * @spa: Supplicant address 232 * @session_timeout: Session timeout 233 * @eapol: Pointer to EAPOL state machine data 234 * @akmp: WPA_KEY_MGMT_* used in key derivation 235 * Returns: Pointer to the added PMKSA cache entry or %NULL on error 236 * 237 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA 238 * cache. If an old entry is already in the cache for the same Supplicant, 239 * this entry will be replaced with the new entry. PMKID will be calculated 240 * based on the PMK. 241 */ 242 struct rsn_pmksa_cache_entry * 243 pmksa_cache_auth_add(struct rsn_pmksa_cache *pmksa, 244 const u8 *pmk, size_t pmk_len, 245 const u8 *aa, const u8 *spa, int session_timeout, 246 struct eapol_state_machine *eapol, int akmp) 247 { 248 struct rsn_pmksa_cache_entry *entry, *pos; 249 struct os_reltime now; 250 251 if (pmk_len > PMK_LEN) 252 return NULL; 253 254 entry = os_zalloc(sizeof(*entry)); 255 if (entry == NULL) 256 return NULL; 257 os_memcpy(entry->pmk, pmk, pmk_len); 258 entry->pmk_len = pmk_len; 259 rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid, 260 wpa_key_mgmt_sha256(akmp)); 261 os_get_reltime(&now); 262 entry->expiration = now.sec; 263 if (session_timeout > 0) 264 entry->expiration += session_timeout; 265 else 266 entry->expiration += dot11RSNAConfigPMKLifetime; 267 entry->akmp = akmp; 268 os_memcpy(entry->spa, spa, ETH_ALEN); 269 pmksa_cache_from_eapol_data(entry, eapol); 270 271 /* Replace an old entry for the same STA (if found) with the new entry 272 */ 273 pos = pmksa_cache_auth_get(pmksa, spa, NULL); 274 if (pos) 275 pmksa_cache_free_entry(pmksa, pos); 276 277 if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) { 278 /* Remove the oldest entry to make room for the new entry */ 279 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache " 280 "entry (for " MACSTR ") to make room for new one", 281 MAC2STR(pmksa->pmksa->spa)); 282 pmksa_cache_free_entry(pmksa, pmksa->pmksa); 283 } 284 285 pmksa_cache_link_entry(pmksa, entry); 286 287 return entry; 288 } 289 290 291 struct rsn_pmksa_cache_entry * 292 pmksa_cache_add_okc(struct rsn_pmksa_cache *pmksa, 293 const struct rsn_pmksa_cache_entry *old_entry, 294 const u8 *aa, const u8 *pmkid) 295 { 296 struct rsn_pmksa_cache_entry *entry; 297 298 entry = os_zalloc(sizeof(*entry)); 299 if (entry == NULL) 300 return NULL; 301 os_memcpy(entry->pmkid, pmkid, PMKID_LEN); 302 os_memcpy(entry->pmk, old_entry->pmk, old_entry->pmk_len); 303 entry->pmk_len = old_entry->pmk_len; 304 entry->expiration = old_entry->expiration; 305 entry->akmp = old_entry->akmp; 306 os_memcpy(entry->spa, old_entry->spa, ETH_ALEN); 307 entry->opportunistic = 1; 308 if (old_entry->identity) { 309 entry->identity = os_malloc(old_entry->identity_len); 310 if (entry->identity) { 311 entry->identity_len = old_entry->identity_len; 312 os_memcpy(entry->identity, old_entry->identity, 313 old_entry->identity_len); 314 } 315 } 316 if (old_entry->cui) 317 entry->cui = wpabuf_dup(old_entry->cui); 318 #ifndef CONFIG_NO_RADIUS 319 radius_copy_class(&entry->radius_class, &old_entry->radius_class); 320 #endif /* CONFIG_NO_RADIUS */ 321 entry->eap_type_authsrv = old_entry->eap_type_authsrv; 322 entry->vlan_id = old_entry->vlan_id; 323 entry->opportunistic = 1; 324 325 pmksa_cache_link_entry(pmksa, entry); 326 327 return entry; 328 } 329 330 331 /** 332 * pmksa_cache_auth_deinit - Free all entries in PMKSA cache 333 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init() 334 */ 335 void pmksa_cache_auth_deinit(struct rsn_pmksa_cache *pmksa) 336 { 337 struct rsn_pmksa_cache_entry *entry, *prev; 338 int i; 339 340 if (pmksa == NULL) 341 return; 342 343 entry = pmksa->pmksa; 344 while (entry) { 345 prev = entry; 346 entry = entry->next; 347 _pmksa_cache_free_entry(prev); 348 } 349 eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL); 350 pmksa->pmksa_count = 0; 351 pmksa->pmksa = NULL; 352 for (i = 0; i < PMKID_HASH_SIZE; i++) 353 pmksa->pmkid[i] = NULL; 354 os_free(pmksa); 355 } 356 357 358 /** 359 * pmksa_cache_auth_get - Fetch a PMKSA cache entry 360 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init() 361 * @spa: Supplicant address or %NULL to match any 362 * @pmkid: PMKID or %NULL to match any 363 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found 364 */ 365 struct rsn_pmksa_cache_entry * 366 pmksa_cache_auth_get(struct rsn_pmksa_cache *pmksa, 367 const u8 *spa, const u8 *pmkid) 368 { 369 struct rsn_pmksa_cache_entry *entry; 370 371 if (pmkid) { 372 for (entry = pmksa->pmkid[PMKID_HASH(pmkid)]; entry; 373 entry = entry->hnext) { 374 if ((spa == NULL || 375 os_memcmp(entry->spa, spa, ETH_ALEN) == 0) && 376 os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) 377 return entry; 378 } 379 } else { 380 for (entry = pmksa->pmksa; entry; entry = entry->next) { 381 if (spa == NULL || 382 os_memcmp(entry->spa, spa, ETH_ALEN) == 0) 383 return entry; 384 } 385 } 386 387 return NULL; 388 } 389 390 391 /** 392 * pmksa_cache_get_okc - Fetch a PMKSA cache entry using OKC 393 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init() 394 * @aa: Authenticator address 395 * @spa: Supplicant address 396 * @pmkid: PMKID 397 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found 398 * 399 * Use opportunistic key caching (OKC) to find a PMK for a supplicant. 400 */ 401 struct rsn_pmksa_cache_entry * pmksa_cache_get_okc( 402 struct rsn_pmksa_cache *pmksa, const u8 *aa, const u8 *spa, 403 const u8 *pmkid) 404 { 405 struct rsn_pmksa_cache_entry *entry; 406 u8 new_pmkid[PMKID_LEN]; 407 408 for (entry = pmksa->pmksa; entry; entry = entry->next) { 409 if (os_memcmp(entry->spa, spa, ETH_ALEN) != 0) 410 continue; 411 rsn_pmkid(entry->pmk, entry->pmk_len, aa, spa, new_pmkid, 412 wpa_key_mgmt_sha256(entry->akmp)); 413 if (os_memcmp(new_pmkid, pmkid, PMKID_LEN) == 0) 414 return entry; 415 } 416 return NULL; 417 } 418 419 420 /** 421 * pmksa_cache_auth_init - Initialize PMKSA cache 422 * @free_cb: Callback function to be called when a PMKSA cache entry is freed 423 * @ctx: Context pointer for free_cb function 424 * Returns: Pointer to PMKSA cache data or %NULL on failure 425 */ 426 struct rsn_pmksa_cache * 427 pmksa_cache_auth_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry, 428 void *ctx), void *ctx) 429 { 430 struct rsn_pmksa_cache *pmksa; 431 432 pmksa = os_zalloc(sizeof(*pmksa)); 433 if (pmksa) { 434 pmksa->free_cb = free_cb; 435 pmksa->ctx = ctx; 436 } 437 438 return pmksa; 439 } 440
