1 /* 2 * RSN pre-authentication (supplicant) 3 * Copyright (c) 2003-2012, 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 "includes.h" 10 11 #include "common.h" 12 #include "wpa.h" 13 #include "eloop.h" 14 #include "l2_packet/l2_packet.h" 15 #include "eapol_supp/eapol_supp_sm.h" 16 #include "preauth.h" 17 #include "pmksa_cache.h" 18 #include "wpa_i.h" 19 20 21 #ifdef IEEE8021X_EAPOL 22 23 #define PMKID_CANDIDATE_PRIO_SCAN 1000 24 25 26 struct rsn_pmksa_candidate { 27 struct dl_list list; 28 u8 bssid[ETH_ALEN]; 29 int priority; 30 }; 31 32 33 /** 34 * pmksa_candidate_free - Free all entries in PMKSA candidate list 35 * @sm: Pointer to WPA state machine data from wpa_sm_init() 36 */ 37 void pmksa_candidate_free(struct wpa_sm *sm) 38 { 39 struct rsn_pmksa_candidate *entry, *n; 40 41 if (sm == NULL) 42 return; 43 44 dl_list_for_each_safe(entry, n, &sm->pmksa_candidates, 45 struct rsn_pmksa_candidate, list) { 46 dl_list_del(&entry->list); 47 os_free(entry); 48 } 49 } 50 51 52 static void rsn_preauth_receive(void *ctx, const u8 *src_addr, 53 const u8 *buf, size_t len) 54 { 55 struct wpa_sm *sm = ctx; 56 57 wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr)); 58 wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len); 59 60 if (sm->preauth_eapol == NULL || 61 is_zero_ether_addr(sm->preauth_bssid) || 62 os_memcmp(sm->preauth_bssid, src_addr, ETH_ALEN) != 0) { 63 wpa_printf(MSG_WARNING, "RSN pre-auth frame received from " 64 "unexpected source " MACSTR " - dropped", 65 MAC2STR(src_addr)); 66 return; 67 } 68 69 eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len); 70 } 71 72 73 static void rsn_preauth_eapol_cb(struct eapol_sm *eapol, 74 enum eapol_supp_result result, 75 void *ctx) 76 { 77 struct wpa_sm *sm = ctx; 78 u8 pmk[PMK_LEN]; 79 80 if (result == EAPOL_SUPP_RESULT_SUCCESS) { 81 int res, pmk_len; 82 pmk_len = PMK_LEN; 83 res = eapol_sm_get_key(eapol, pmk, PMK_LEN); 84 if (res) { 85 /* 86 * EAP-LEAP is an exception from other EAP methods: it 87 * uses only 16-byte PMK. 88 */ 89 res = eapol_sm_get_key(eapol, pmk, 16); 90 pmk_len = 16; 91 } 92 if (res == 0) { 93 wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth", 94 pmk, pmk_len); 95 sm->pmk_len = pmk_len; 96 pmksa_cache_add(sm->pmksa, pmk, pmk_len, 97 sm->preauth_bssid, sm->own_addr, 98 sm->network_ctx, 99 WPA_KEY_MGMT_IEEE8021X); 100 } else { 101 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, 102 "RSN: failed to get master session key from " 103 "pre-auth EAPOL state machines"); 104 result = EAPOL_SUPP_RESULT_FAILURE; 105 } 106 } 107 108 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 109 MACSTR " %s", MAC2STR(sm->preauth_bssid), 110 result == EAPOL_SUPP_RESULT_SUCCESS ? "completed successfully" : 111 "failed"); 112 113 rsn_preauth_deinit(sm); 114 rsn_preauth_candidate_process(sm); 115 } 116 117 118 static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx) 119 { 120 struct wpa_sm *sm = eloop_ctx; 121 122 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 123 MACSTR " timed out", MAC2STR(sm->preauth_bssid)); 124 rsn_preauth_deinit(sm); 125 rsn_preauth_candidate_process(sm); 126 } 127 128 129 static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf, 130 size_t len) 131 { 132 struct wpa_sm *sm = ctx; 133 u8 *msg; 134 size_t msglen; 135 int res; 136 137 /* TODO: could add l2_packet_sendmsg that allows fragments to avoid 138 * extra copy here */ 139 140 if (sm->l2_preauth == NULL) 141 return -1; 142 143 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL); 144 if (msg == NULL) 145 return -1; 146 147 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen); 148 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid, 149 ETH_P_RSN_PREAUTH, msg, msglen); 150 os_free(msg); 151 return res; 152 } 153 154 155 /** 156 * rsn_preauth_init - Start new RSN pre-authentication 157 * @sm: Pointer to WPA state machine data from wpa_sm_init() 158 * @dst: Authenticator address (BSSID) with which to preauthenticate 159 * @eap_conf: Current EAP configuration 160 * Returns: 0 on success, -1 on another pre-authentication is in progress, 161 * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine 162 * initialization failure, -4 on memory allocation failure 163 * 164 * This function request an RSN pre-authentication with a given destination 165 * address. This is usually called for PMKSA candidates found from scan results 166 * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger 167 * pre-authentication. 168 */ 169 int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst, 170 struct eap_peer_config *eap_conf) 171 { 172 struct eapol_config eapol_conf; 173 struct eapol_ctx *ctx; 174 175 if (sm->preauth_eapol) 176 return -1; 177 178 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, 179 "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst)); 180 181 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr, 182 ETH_P_RSN_PREAUTH, 183 rsn_preauth_receive, sm, 0); 184 if (sm->l2_preauth == NULL) { 185 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet " 186 "processing for pre-authentication"); 187 return -2; 188 } 189 190 if (sm->bridge_ifname) { 191 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname, 192 sm->own_addr, 193 ETH_P_RSN_PREAUTH, 194 rsn_preauth_receive, sm, 0); 195 if (sm->l2_preauth_br == NULL) { 196 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 " 197 "packet processing (bridge) for " 198 "pre-authentication"); 199 return -2; 200 } 201 } 202 203 ctx = os_zalloc(sizeof(*ctx)); 204 if (ctx == NULL) { 205 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context."); 206 return -4; 207 } 208 ctx->ctx = sm->ctx->ctx; 209 ctx->msg_ctx = sm->ctx->ctx; 210 ctx->preauth = 1; 211 ctx->cb = rsn_preauth_eapol_cb; 212 ctx->cb_ctx = sm; 213 ctx->scard_ctx = sm->scard_ctx; 214 ctx->eapol_send = rsn_preauth_eapol_send; 215 ctx->eapol_send_ctx = sm; 216 ctx->set_config_blob = sm->ctx->set_config_blob; 217 ctx->get_config_blob = sm->ctx->get_config_blob; 218 219 sm->preauth_eapol = eapol_sm_init(ctx); 220 if (sm->preauth_eapol == NULL) { 221 os_free(ctx); 222 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL " 223 "state machines for pre-authentication"); 224 return -3; 225 } 226 os_memset(&eapol_conf, 0, sizeof(eapol_conf)); 227 eapol_conf.accept_802_1x_keys = 0; 228 eapol_conf.required_keys = 0; 229 eapol_conf.fast_reauth = sm->fast_reauth; 230 eapol_conf.workaround = sm->eap_workaround; 231 eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf); 232 /* 233 * Use a shorter startPeriod with preauthentication since the first 234 * preauth EAPOL-Start frame may end up being dropped due to race 235 * condition in the AP between the data receive and key configuration 236 * after the 4-Way Handshake. 237 */ 238 eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6); 239 os_memcpy(sm->preauth_bssid, dst, ETH_ALEN); 240 241 eapol_sm_notify_portValid(sm->preauth_eapol, TRUE); 242 /* 802.1X::portControl = Auto */ 243 eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE); 244 245 eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0, 246 rsn_preauth_timeout, sm, NULL); 247 248 return 0; 249 } 250 251 252 /** 253 * rsn_preauth_deinit - Abort RSN pre-authentication 254 * @sm: Pointer to WPA state machine data from wpa_sm_init() 255 * 256 * This function aborts the current RSN pre-authentication (if one is started) 257 * and frees resources allocated for it. 258 */ 259 void rsn_preauth_deinit(struct wpa_sm *sm) 260 { 261 if (sm == NULL || !sm->preauth_eapol) 262 return; 263 264 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL); 265 eapol_sm_deinit(sm->preauth_eapol); 266 sm->preauth_eapol = NULL; 267 os_memset(sm->preauth_bssid, 0, ETH_ALEN); 268 269 l2_packet_deinit(sm->l2_preauth); 270 sm->l2_preauth = NULL; 271 if (sm->l2_preauth_br) { 272 l2_packet_deinit(sm->l2_preauth_br); 273 sm->l2_preauth_br = NULL; 274 } 275 } 276 277 278 /** 279 * rsn_preauth_candidate_process - Process PMKSA candidates 280 * @sm: Pointer to WPA state machine data from wpa_sm_init() 281 * 282 * Go through the PMKSA candidates and start pre-authentication if a candidate 283 * without an existing PMKSA cache entry is found. Processed candidates will be 284 * removed from the list. 285 */ 286 void rsn_preauth_candidate_process(struct wpa_sm *sm) 287 { 288 struct rsn_pmksa_candidate *candidate, *n; 289 290 if (dl_list_empty(&sm->pmksa_candidates)) 291 return; 292 293 /* TODO: drop priority for old candidate entries */ 294 295 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate " 296 "list"); 297 if (sm->preauth_eapol || 298 sm->proto != WPA_PROTO_RSN || 299 wpa_sm_get_state(sm) != WPA_COMPLETED || 300 (sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X && 301 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256)) { 302 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable " 303 "state for new pre-authentication"); 304 return; /* invalid state for new pre-auth */ 305 } 306 307 dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates, 308 struct rsn_pmksa_candidate, list) { 309 struct rsn_pmksa_cache_entry *p = NULL; 310 p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL, NULL); 311 if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 && 312 (p == NULL || p->opportunistic)) { 313 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA " 314 "candidate " MACSTR 315 " selected for pre-authentication", 316 MAC2STR(candidate->bssid)); 317 dl_list_del(&candidate->list); 318 rsn_preauth_init(sm, candidate->bssid, 319 sm->eap_conf_ctx); 320 os_free(candidate); 321 return; 322 } 323 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate " 324 MACSTR " does not need pre-authentication anymore", 325 MAC2STR(candidate->bssid)); 326 /* Some drivers (e.g., NDIS) expect to get notified about the 327 * PMKIDs again, so report the existing data now. */ 328 if (p) { 329 wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid); 330 } 331 332 dl_list_del(&candidate->list); 333 os_free(candidate); 334 } 335 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA " 336 "candidates"); 337 } 338 339 340 /** 341 * pmksa_candidate_add - Add a new PMKSA candidate 342 * @sm: Pointer to WPA state machine data from wpa_sm_init() 343 * @bssid: BSSID (authenticator address) of the candidate 344 * @prio: Priority (the smaller number, the higher priority) 345 * @preauth: Whether the candidate AP advertises support for pre-authentication 346 * 347 * This function is used to add PMKSA candidates for RSN pre-authentication. It 348 * is called from scan result processing and from driver events for PMKSA 349 * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event(). 350 */ 351 void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid, 352 int prio, int preauth) 353 { 354 struct rsn_pmksa_candidate *cand, *pos; 355 356 if (sm->network_ctx && sm->proactive_key_caching) 357 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx, 358 bssid); 359 360 if (!preauth) { 361 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without " 362 "preauth flag"); 363 return; 364 } 365 366 /* If BSSID already on candidate list, update the priority of the old 367 * entry. Do not override priority based on normal scan results. */ 368 cand = NULL; 369 dl_list_for_each(pos, &sm->pmksa_candidates, 370 struct rsn_pmksa_candidate, list) { 371 if (os_memcmp(pos->bssid, bssid, ETH_ALEN) == 0) { 372 cand = pos; 373 break; 374 } 375 } 376 377 if (cand) { 378 dl_list_del(&cand->list); 379 if (prio < PMKID_CANDIDATE_PRIO_SCAN) 380 cand->priority = prio; 381 } else { 382 cand = os_zalloc(sizeof(*cand)); 383 if (cand == NULL) 384 return; 385 os_memcpy(cand->bssid, bssid, ETH_ALEN); 386 cand->priority = prio; 387 } 388 389 /* Add candidate to the list; order by increasing priority value. i.e., 390 * highest priority (smallest value) first. */ 391 dl_list_for_each(pos, &sm->pmksa_candidates, 392 struct rsn_pmksa_candidate, list) { 393 if (cand->priority <= pos->priority) { 394 dl_list_add(pos->list.prev, &cand->list); 395 cand = NULL; 396 break; 397 } 398 } 399 if (cand) 400 dl_list_add_tail(&sm->pmksa_candidates, &cand->list); 401 402 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache " 403 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio); 404 rsn_preauth_candidate_process(sm); 405 } 406 407 408 /* TODO: schedule periodic scans if current AP supports preauth */ 409 410 /** 411 * rsn_preauth_scan_results - Start processing scan results for canditates 412 * @sm: Pointer to WPA state machine data from wpa_sm_init() 413 * Returns: 0 if ready to process results or -1 to skip processing 414 * 415 * This functions is used to notify RSN code about start of new scan results 416 * processing. The actual scan results will be provided by calling 417 * rsn_preauth_scan_result() for each BSS if this function returned 0. 418 */ 419 int rsn_preauth_scan_results(struct wpa_sm *sm) 420 { 421 if (sm->ssid_len == 0) 422 return -1; 423 424 /* 425 * TODO: is it ok to free all candidates? What about the entries 426 * received from EVENT_PMKID_CANDIDATE? 427 */ 428 pmksa_candidate_free(sm); 429 430 return 0; 431 } 432 433 434 /** 435 * rsn_preauth_scan_result - Processing scan result for PMKSA canditates 436 * @sm: Pointer to WPA state machine data from wpa_sm_init() 437 * 438 * Add all suitable APs (Authenticators) from scan results into PMKSA 439 * candidate list. 440 */ 441 void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid, 442 const u8 *ssid, const u8 *rsn) 443 { 444 struct wpa_ie_data ie; 445 struct rsn_pmksa_cache_entry *pmksa; 446 447 if (ssid[1] != sm->ssid_len || 448 os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0) 449 return; /* Not for the current SSID */ 450 451 if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0) 452 return; /* Ignore current AP */ 453 454 if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie)) 455 return; 456 457 pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL, NULL); 458 if (pmksa && (!pmksa->opportunistic || 459 !(ie.capabilities & WPA_CAPABILITY_PREAUTH))) 460 return; 461 462 /* Give less priority to candidates found from normal scan results. */ 463 pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN, 464 ie.capabilities & WPA_CAPABILITY_PREAUTH); 465 } 466 467 468 #ifdef CONFIG_CTRL_IFACE 469 /** 470 * rsn_preauth_get_status - Get pre-authentication status 471 * @sm: Pointer to WPA state machine data from wpa_sm_init() 472 * @buf: Buffer for status information 473 * @buflen: Maximum buffer length 474 * @verbose: Whether to include verbose status information 475 * Returns: Number of bytes written to buf. 476 * 477 * Query WPA2 pre-authentication for status information. This function fills in 478 * a text area with current status information. If the buffer (buf) is not 479 * large enough, status information will be truncated to fit the buffer. 480 */ 481 int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen, 482 int verbose) 483 { 484 char *pos = buf, *end = buf + buflen; 485 int res, ret; 486 487 if (sm->preauth_eapol) { 488 ret = os_snprintf(pos, end - pos, "Pre-authentication " 489 "EAPOL state machines:\n"); 490 if (ret < 0 || ret >= end - pos) 491 return pos - buf; 492 pos += ret; 493 res = eapol_sm_get_status(sm->preauth_eapol, 494 pos, end - pos, verbose); 495 if (res >= 0) 496 pos += res; 497 } 498 499 return pos - buf; 500 } 501 #endif /* CONFIG_CTRL_IFACE */ 502 503 504 /** 505 * rsn_preauth_in_progress - Verify whether pre-authentication is in progress 506 * @sm: Pointer to WPA state machine data from wpa_sm_init() 507 */ 508 int rsn_preauth_in_progress(struct wpa_sm *sm) 509 { 510 return sm->preauth_eapol != NULL; 511 } 512 513 #endif /* IEEE8021X_EAPOL */ 514
