1 /* 2 * RSN pre-authentication (supplicant) 3 * Copyright (c) 2003-2015, 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 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA) 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, NULL, 97 NULL, 0, 98 sm->preauth_bssid, sm->own_addr, 99 sm->network_ctx, 100 WPA_KEY_MGMT_IEEE8021X, NULL); 101 } else { 102 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, 103 "RSN: failed to get master session key from " 104 "pre-auth EAPOL state machines"); 105 result = EAPOL_SUPP_RESULT_FAILURE; 106 } 107 } 108 109 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 110 MACSTR " %s", MAC2STR(sm->preauth_bssid), 111 result == EAPOL_SUPP_RESULT_SUCCESS ? "completed successfully" : 112 "failed"); 113 114 rsn_preauth_deinit(sm); 115 rsn_preauth_candidate_process(sm); 116 } 117 118 119 static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx) 120 { 121 struct wpa_sm *sm = eloop_ctx; 122 123 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 124 MACSTR " timed out", MAC2STR(sm->preauth_bssid)); 125 rsn_preauth_deinit(sm); 126 rsn_preauth_candidate_process(sm); 127 } 128 129 130 static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf, 131 size_t len) 132 { 133 struct wpa_sm *sm = ctx; 134 u8 *msg; 135 size_t msglen; 136 int res; 137 138 /* TODO: could add l2_packet_sendmsg that allows fragments to avoid 139 * extra copy here */ 140 141 if (sm->l2_preauth == NULL) 142 return -1; 143 144 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL); 145 if (msg == NULL) 146 return -1; 147 148 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen); 149 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid, 150 ETH_P_RSN_PREAUTH, msg, msglen); 151 os_free(msg); 152 return res; 153 } 154 155 156 /** 157 * rsn_preauth_init - Start new RSN pre-authentication 158 * @sm: Pointer to WPA state machine data from wpa_sm_init() 159 * @dst: Authenticator address (BSSID) with which to preauthenticate 160 * @eap_conf: Current EAP configuration 161 * Returns: 0 on success, -1 on another pre-authentication is in progress, 162 * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine 163 * initialization failure, -4 on memory allocation failure 164 * 165 * This function request an RSN pre-authentication with a given destination 166 * address. This is usually called for PMKSA candidates found from scan results 167 * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger 168 * pre-authentication. 169 */ 170 int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst, 171 struct eap_peer_config *eap_conf) 172 { 173 struct eapol_config eapol_conf; 174 struct eapol_ctx *ctx; 175 int ret; 176 177 if (sm->preauth_eapol) 178 return -1; 179 180 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, 181 "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst)); 182 183 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr, 184 ETH_P_RSN_PREAUTH, 185 rsn_preauth_receive, sm, 0); 186 if (sm->l2_preauth == NULL) { 187 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet " 188 "processing for pre-authentication"); 189 return -2; 190 } 191 192 if (sm->bridge_ifname) { 193 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname, 194 sm->own_addr, 195 ETH_P_RSN_PREAUTH, 196 rsn_preauth_receive, sm, 0); 197 if (sm->l2_preauth_br == NULL) { 198 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 " 199 "packet processing (bridge) for " 200 "pre-authentication"); 201 ret = -2; 202 goto fail; 203 } 204 } 205 206 ctx = os_zalloc(sizeof(*ctx)); 207 if (ctx == NULL) { 208 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context."); 209 ret = -4; 210 goto fail; 211 } 212 ctx->ctx = sm->ctx->ctx; 213 ctx->msg_ctx = sm->ctx->ctx; 214 ctx->preauth = 1; 215 ctx->cb = rsn_preauth_eapol_cb; 216 ctx->cb_ctx = sm; 217 ctx->scard_ctx = sm->scard_ctx; 218 ctx->eapol_send = rsn_preauth_eapol_send; 219 ctx->eapol_send_ctx = sm; 220 ctx->set_config_blob = sm->ctx->set_config_blob; 221 ctx->get_config_blob = sm->ctx->get_config_blob; 222 223 sm->preauth_eapol = eapol_sm_init(ctx); 224 if (sm->preauth_eapol == NULL) { 225 os_free(ctx); 226 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL " 227 "state machines for pre-authentication"); 228 ret = -3; 229 goto fail; 230 } 231 os_memset(&eapol_conf, 0, sizeof(eapol_conf)); 232 eapol_conf.accept_802_1x_keys = 0; 233 eapol_conf.required_keys = 0; 234 eapol_conf.fast_reauth = sm->fast_reauth; 235 eapol_conf.workaround = sm->eap_workaround; 236 eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf); 237 /* 238 * Use a shorter startPeriod with preauthentication since the first 239 * preauth EAPOL-Start frame may end up being dropped due to race 240 * condition in the AP between the data receive and key configuration 241 * after the 4-Way Handshake. 242 */ 243 eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6); 244 os_memcpy(sm->preauth_bssid, dst, ETH_ALEN); 245 246 eapol_sm_notify_portValid(sm->preauth_eapol, TRUE); 247 /* 802.1X::portControl = Auto */ 248 eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE); 249 250 eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0, 251 rsn_preauth_timeout, sm, NULL); 252 253 return 0; 254 255 fail: 256 if (sm->l2_preauth_br) { 257 l2_packet_deinit(sm->l2_preauth_br); 258 sm->l2_preauth_br = NULL; 259 } 260 l2_packet_deinit(sm->l2_preauth); 261 sm->l2_preauth = NULL; 262 return ret; 263 } 264 265 266 /** 267 * rsn_preauth_deinit - Abort RSN pre-authentication 268 * @sm: Pointer to WPA state machine data from wpa_sm_init() 269 * 270 * This function aborts the current RSN pre-authentication (if one is started) 271 * and frees resources allocated for it. 272 */ 273 void rsn_preauth_deinit(struct wpa_sm *sm) 274 { 275 if (sm == NULL || !sm->preauth_eapol) 276 return; 277 278 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL); 279 eapol_sm_deinit(sm->preauth_eapol); 280 sm->preauth_eapol = NULL; 281 os_memset(sm->preauth_bssid, 0, ETH_ALEN); 282 283 l2_packet_deinit(sm->l2_preauth); 284 sm->l2_preauth = NULL; 285 if (sm->l2_preauth_br) { 286 l2_packet_deinit(sm->l2_preauth_br); 287 sm->l2_preauth_br = NULL; 288 } 289 } 290 291 292 /** 293 * rsn_preauth_candidate_process - Process PMKSA candidates 294 * @sm: Pointer to WPA state machine data from wpa_sm_init() 295 * 296 * Go through the PMKSA candidates and start pre-authentication if a candidate 297 * without an existing PMKSA cache entry is found. Processed candidates will be 298 * removed from the list. 299 */ 300 void rsn_preauth_candidate_process(struct wpa_sm *sm) 301 { 302 struct rsn_pmksa_candidate *candidate, *n; 303 304 if (dl_list_empty(&sm->pmksa_candidates)) 305 return; 306 307 /* TODO: drop priority for old candidate entries */ 308 309 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate " 310 "list"); 311 if (sm->preauth_eapol || 312 sm->proto != WPA_PROTO_RSN || 313 wpa_sm_get_state(sm) != WPA_COMPLETED || 314 (sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X && 315 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256 && 316 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SUITE_B && 317 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SUITE_B_192)) { 318 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable " 319 "state for new pre-authentication"); 320 return; /* invalid state for new pre-auth */ 321 } 322 323 dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates, 324 struct rsn_pmksa_candidate, list) { 325 struct rsn_pmksa_cache_entry *p = NULL; 326 p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL, NULL, 0); 327 if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 && 328 (p == NULL || p->opportunistic)) { 329 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA " 330 "candidate " MACSTR 331 " selected for pre-authentication", 332 MAC2STR(candidate->bssid)); 333 dl_list_del(&candidate->list); 334 rsn_preauth_init(sm, candidate->bssid, 335 sm->eap_conf_ctx); 336 os_free(candidate); 337 return; 338 } 339 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate " 340 MACSTR " does not need pre-authentication anymore", 341 MAC2STR(candidate->bssid)); 342 /* Some drivers (e.g., NDIS) expect to get notified about the 343 * PMKIDs again, so report the existing data now. */ 344 if (p) { 345 wpa_sm_add_pmkid(sm, NULL, candidate->bssid, p->pmkid, 346 NULL, p->pmk, p->pmk_len); 347 } 348 349 dl_list_del(&candidate->list); 350 os_free(candidate); 351 } 352 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA " 353 "candidates"); 354 } 355 356 357 /** 358 * pmksa_candidate_add - Add a new PMKSA candidate 359 * @sm: Pointer to WPA state machine data from wpa_sm_init() 360 * @bssid: BSSID (authenticator address) of the candidate 361 * @prio: Priority (the smaller number, the higher priority) 362 * @preauth: Whether the candidate AP advertises support for pre-authentication 363 * 364 * This function is used to add PMKSA candidates for RSN pre-authentication. It 365 * is called from scan result processing and from driver events for PMKSA 366 * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event(). 367 */ 368 void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid, 369 int prio, int preauth) 370 { 371 struct rsn_pmksa_candidate *cand, *pos; 372 373 if (sm->network_ctx && sm->proactive_key_caching) 374 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx, 375 bssid, 0); 376 377 if (!preauth) { 378 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without " 379 "preauth flag"); 380 return; 381 } 382 383 /* If BSSID already on candidate list, update the priority of the old 384 * entry. Do not override priority based on normal scan results. */ 385 cand = NULL; 386 dl_list_for_each(pos, &sm->pmksa_candidates, 387 struct rsn_pmksa_candidate, list) { 388 if (os_memcmp(pos->bssid, bssid, ETH_ALEN) == 0) { 389 cand = pos; 390 break; 391 } 392 } 393 394 if (cand) { 395 dl_list_del(&cand->list); 396 if (prio < PMKID_CANDIDATE_PRIO_SCAN) 397 cand->priority = prio; 398 } else { 399 cand = os_zalloc(sizeof(*cand)); 400 if (cand == NULL) 401 return; 402 os_memcpy(cand->bssid, bssid, ETH_ALEN); 403 cand->priority = prio; 404 } 405 406 /* Add candidate to the list; order by increasing priority value. i.e., 407 * highest priority (smallest value) first. */ 408 dl_list_for_each(pos, &sm->pmksa_candidates, 409 struct rsn_pmksa_candidate, list) { 410 if (cand->priority <= pos->priority) { 411 if (!pos->list.prev) { 412 /* 413 * This cannot really happen in pracrice since 414 * pos was fetched from the list and the prev 415 * pointer must be set. It looks like clang 416 * static analyzer gets confused with the 417 * dl_list_del(&cand->list) call above and ends 418 * up assuming pos->list.prev could be NULL. 419 */ 420 os_free(cand); 421 return; 422 } 423 dl_list_add(pos->list.prev, &cand->list); 424 cand = NULL; 425 break; 426 } 427 } 428 if (cand) 429 dl_list_add_tail(&sm->pmksa_candidates, &cand->list); 430 431 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache " 432 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio); 433 rsn_preauth_candidate_process(sm); 434 } 435 436 437 /* TODO: schedule periodic scans if current AP supports preauth */ 438 439 /** 440 * rsn_preauth_scan_results - Start processing scan results for canditates 441 * @sm: Pointer to WPA state machine data from wpa_sm_init() 442 * Returns: 0 if ready to process results or -1 to skip processing 443 * 444 * This functions is used to notify RSN code about start of new scan results 445 * processing. The actual scan results will be provided by calling 446 * rsn_preauth_scan_result() for each BSS if this function returned 0. 447 */ 448 int rsn_preauth_scan_results(struct wpa_sm *sm) 449 { 450 if (sm->ssid_len == 0) 451 return -1; 452 453 /* 454 * TODO: is it ok to free all candidates? What about the entries 455 * received from EVENT_PMKID_CANDIDATE? 456 */ 457 pmksa_candidate_free(sm); 458 459 return 0; 460 } 461 462 463 /** 464 * rsn_preauth_scan_result - Processing scan result for PMKSA canditates 465 * @sm: Pointer to WPA state machine data from wpa_sm_init() 466 * 467 * Add all suitable APs (Authenticators) from scan results into PMKSA 468 * candidate list. 469 */ 470 void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid, 471 const u8 *ssid, const u8 *rsn) 472 { 473 struct wpa_ie_data ie; 474 struct rsn_pmksa_cache_entry *pmksa; 475 476 if (ssid[1] != sm->ssid_len || 477 os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0) 478 return; /* Not for the current SSID */ 479 480 if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0) 481 return; /* Ignore current AP */ 482 483 if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie)) 484 return; 485 486 pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL, NULL, 0); 487 if (pmksa && (!pmksa->opportunistic || 488 !(ie.capabilities & WPA_CAPABILITY_PREAUTH))) 489 return; 490 491 /* Give less priority to candidates found from normal scan results. */ 492 pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN, 493 ie.capabilities & WPA_CAPABILITY_PREAUTH); 494 } 495 496 497 #ifdef CONFIG_CTRL_IFACE 498 /** 499 * rsn_preauth_get_status - Get pre-authentication status 500 * @sm: Pointer to WPA state machine data from wpa_sm_init() 501 * @buf: Buffer for status information 502 * @buflen: Maximum buffer length 503 * @verbose: Whether to include verbose status information 504 * Returns: Number of bytes written to buf. 505 * 506 * Query WPA2 pre-authentication for status information. This function fills in 507 * a text area with current status information. If the buffer (buf) is not 508 * large enough, status information will be truncated to fit the buffer. 509 */ 510 int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen, 511 int verbose) 512 { 513 char *pos = buf, *end = buf + buflen; 514 int res, ret; 515 516 if (sm->preauth_eapol) { 517 ret = os_snprintf(pos, end - pos, "Pre-authentication " 518 "EAPOL state machines:\n"); 519 if (os_snprintf_error(end - pos, ret)) 520 return pos - buf; 521 pos += ret; 522 res = eapol_sm_get_status(sm->preauth_eapol, 523 pos, end - pos, verbose); 524 if (res >= 0) 525 pos += res; 526 } 527 528 return pos - buf; 529 } 530 #endif /* CONFIG_CTRL_IFACE */ 531 532 533 /** 534 * rsn_preauth_in_progress - Verify whether pre-authentication is in progress 535 * @sm: Pointer to WPA state machine data from wpa_sm_init() 536 */ 537 int rsn_preauth_in_progress(struct wpa_sm *sm) 538 { 539 return sm->preauth_eapol != NULL; 540 } 541 542 #endif /* IEEE8021X_EAPOL && !CONFIG_NO_WPA */ 543
