1 /* 2 * RSN pre-authentication (supplicant) 3 * Copyright (c) 2003-2015, Jouni Malinen <j@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 */ pmksa_candidate_free(struct wpa_sm * sm)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 rsn_preauth_key_mgmt(int akmp)52 static int rsn_preauth_key_mgmt(int akmp) 53 { 54 return !!(akmp & (WPA_KEY_MGMT_IEEE8021X | 55 WPA_KEY_MGMT_IEEE8021X_SHA256 | 56 WPA_KEY_MGMT_IEEE8021X_SUITE_B | 57 WPA_KEY_MGMT_IEEE8021X_SUITE_B_192 | 58 WPA_KEY_MGMT_IEEE8021X_SHA384)); 59 } 60 61 rsn_preauth_receive(void * ctx,const u8 * src_addr,const u8 * buf,size_t len)62 static void rsn_preauth_receive(void *ctx, const u8 *src_addr, 63 const u8 *buf, size_t len) 64 { 65 struct wpa_sm *sm = ctx; 66 67 wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr)); 68 wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len); 69 70 if (sm->preauth_eapol == NULL || 71 is_zero_ether_addr(sm->preauth_bssid) || 72 !ether_addr_equal(sm->preauth_bssid, src_addr)) { 73 wpa_printf(MSG_WARNING, "RSN pre-auth frame received from " 74 "unexpected source " MACSTR " - dropped", 75 MAC2STR(src_addr)); 76 return; 77 } 78 79 eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len, 80 FRAME_ENCRYPTION_UNKNOWN); 81 } 82 83 rsn_preauth_eapol_cb(struct eapol_sm * eapol,enum eapol_supp_result result,void * ctx)84 static void rsn_preauth_eapol_cb(struct eapol_sm *eapol, 85 enum eapol_supp_result result, 86 void *ctx) 87 { 88 struct wpa_sm *sm = ctx; 89 u8 pmk[PMK_LEN]; 90 91 if (result == EAPOL_SUPP_RESULT_SUCCESS) { 92 int res, pmk_len; 93 pmk_len = PMK_LEN; 94 res = eapol_sm_get_key(eapol, pmk, PMK_LEN); 95 if (res) { 96 /* 97 * EAP-LEAP is an exception from other EAP methods: it 98 * uses only 16-byte PMK. 99 */ 100 res = eapol_sm_get_key(eapol, pmk, 16); 101 pmk_len = 16; 102 } 103 if (res == 0) { 104 wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth", 105 pmk, pmk_len); 106 sm->pmk_len = pmk_len; 107 pmksa_cache_add(sm->pmksa, pmk, pmk_len, NULL, 108 NULL, 0, 109 sm->preauth_bssid, sm->own_addr, 110 sm->network_ctx, 111 WPA_KEY_MGMT_IEEE8021X, NULL); 112 } else { 113 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, 114 "RSN: failed to get master session key from " 115 "pre-auth EAPOL state machines"); 116 result = EAPOL_SUPP_RESULT_FAILURE; 117 } 118 } 119 120 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 121 MACSTR " %s", MAC2STR(sm->preauth_bssid), 122 result == EAPOL_SUPP_RESULT_SUCCESS ? "completed successfully" : 123 "failed"); 124 125 rsn_preauth_deinit(sm); 126 rsn_preauth_candidate_process(sm); 127 } 128 129 rsn_preauth_timeout(void * eloop_ctx,void * timeout_ctx)130 static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx) 131 { 132 struct wpa_sm *sm = eloop_ctx; 133 134 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 135 MACSTR " timed out", MAC2STR(sm->preauth_bssid)); 136 rsn_preauth_deinit(sm); 137 rsn_preauth_candidate_process(sm); 138 } 139 140 rsn_preauth_eapol_send(void * ctx,int type,const u8 * buf,size_t len)141 static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf, 142 size_t len) 143 { 144 struct wpa_sm *sm = ctx; 145 u8 *msg; 146 size_t msglen; 147 int res; 148 149 /* TODO: could add l2_packet_sendmsg that allows fragments to avoid 150 * extra copy here */ 151 152 if (sm->l2_preauth == NULL) 153 return -1; 154 155 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL); 156 if (msg == NULL) 157 return -1; 158 159 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen); 160 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid, 161 ETH_P_RSN_PREAUTH, msg, msglen); 162 os_free(msg); 163 return res; 164 } 165 166 167 /** 168 * rsn_preauth_init - Start new RSN pre-authentication 169 * @sm: Pointer to WPA state machine data from wpa_sm_init() 170 * @dst: Authenticator address (BSSID) with which to preauthenticate 171 * @eap_conf: Current EAP configuration 172 * Returns: 0 on success, -1 on another pre-authentication is in progress, 173 * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine 174 * initialization failure, -4 on memory allocation failure 175 * 176 * This function request an RSN pre-authentication with a given destination 177 * address. This is usually called for PMKSA candidates found from scan results 178 * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger 179 * pre-authentication. 180 */ rsn_preauth_init(struct wpa_sm * sm,const u8 * dst,struct eap_peer_config * eap_conf)181 int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst, 182 struct eap_peer_config *eap_conf) 183 { 184 struct eapol_config eapol_conf; 185 struct eapol_ctx *ctx; 186 int ret; 187 188 if (sm->preauth_eapol) 189 return -1; 190 191 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, 192 "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst)); 193 194 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr, 195 ETH_P_RSN_PREAUTH, 196 rsn_preauth_receive, sm, 0); 197 if (sm->l2_preauth == NULL) { 198 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet " 199 "processing for pre-authentication"); 200 return -2; 201 } 202 203 if (sm->bridge_ifname) { 204 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname, 205 sm->own_addr, 206 ETH_P_RSN_PREAUTH, 207 rsn_preauth_receive, sm, 0); 208 if (sm->l2_preauth_br == NULL) { 209 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 " 210 "packet processing (bridge) for " 211 "pre-authentication"); 212 ret = -2; 213 goto fail; 214 } 215 } 216 217 ctx = os_zalloc(sizeof(*ctx)); 218 if (ctx == NULL) { 219 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context."); 220 ret = -4; 221 goto fail; 222 } 223 ctx->ctx = sm->ctx->ctx; 224 ctx->msg_ctx = sm->ctx->ctx; 225 ctx->preauth = 1; 226 ctx->cb = rsn_preauth_eapol_cb; 227 ctx->cb_ctx = sm; 228 ctx->scard_ctx = sm->scard_ctx; 229 ctx->eapol_send = rsn_preauth_eapol_send; 230 ctx->eapol_send_ctx = sm; 231 ctx->set_config_blob = sm->ctx->set_config_blob; 232 ctx->get_config_blob = sm->ctx->get_config_blob; 233 234 sm->preauth_eapol = eapol_sm_init(ctx); 235 if (sm->preauth_eapol == NULL) { 236 os_free(ctx); 237 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL " 238 "state machines for pre-authentication"); 239 ret = -3; 240 goto fail; 241 } 242 os_memset(&eapol_conf, 0, sizeof(eapol_conf)); 243 eapol_conf.accept_802_1x_keys = 0; 244 eapol_conf.required_keys = 0; 245 eapol_conf.fast_reauth = sm->fast_reauth; 246 eapol_conf.workaround = sm->eap_workaround; 247 eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf); 248 /* 249 * Use a shorter startPeriod with preauthentication since the first 250 * preauth EAPOL-Start frame may end up being dropped due to race 251 * condition in the AP between the data receive and key configuration 252 * after the 4-Way Handshake. 253 */ 254 eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6); 255 os_memcpy(sm->preauth_bssid, dst, ETH_ALEN); 256 257 eapol_sm_notify_portValid(sm->preauth_eapol, true); 258 /* 802.1X::portControl = Auto */ 259 eapol_sm_notify_portEnabled(sm->preauth_eapol, true); 260 261 eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0, 262 rsn_preauth_timeout, sm, NULL); 263 264 return 0; 265 266 fail: 267 if (sm->l2_preauth_br) { 268 l2_packet_deinit(sm->l2_preauth_br); 269 sm->l2_preauth_br = NULL; 270 } 271 l2_packet_deinit(sm->l2_preauth); 272 sm->l2_preauth = NULL; 273 return ret; 274 } 275 276 277 /** 278 * rsn_preauth_deinit - Abort RSN pre-authentication 279 * @sm: Pointer to WPA state machine data from wpa_sm_init() 280 * 281 * This function aborts the current RSN pre-authentication (if one is started) 282 * and frees resources allocated for it. 283 */ rsn_preauth_deinit(struct wpa_sm * sm)284 void rsn_preauth_deinit(struct wpa_sm *sm) 285 { 286 if (sm == NULL || !sm->preauth_eapol) 287 return; 288 289 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL); 290 eapol_sm_deinit(sm->preauth_eapol); 291 sm->preauth_eapol = NULL; 292 os_memset(sm->preauth_bssid, 0, ETH_ALEN); 293 294 l2_packet_deinit(sm->l2_preauth); 295 sm->l2_preauth = NULL; 296 if (sm->l2_preauth_br) { 297 l2_packet_deinit(sm->l2_preauth_br); 298 sm->l2_preauth_br = NULL; 299 } 300 } 301 302 303 /** 304 * rsn_preauth_candidate_process - Process PMKSA candidates 305 * @sm: Pointer to WPA state machine data from wpa_sm_init() 306 * 307 * Go through the PMKSA candidates and start pre-authentication if a candidate 308 * without an existing PMKSA cache entry is found. Processed candidates will be 309 * removed from the list. 310 */ rsn_preauth_candidate_process(struct wpa_sm * sm)311 void rsn_preauth_candidate_process(struct wpa_sm *sm) 312 { 313 struct rsn_pmksa_candidate *candidate, *n; 314 315 if (dl_list_empty(&sm->pmksa_candidates)) 316 return; 317 318 /* TODO: drop priority for old candidate entries */ 319 320 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate " 321 "list"); 322 if (sm->preauth_eapol || 323 sm->proto != WPA_PROTO_RSN || 324 wpa_sm_get_state(sm) != WPA_COMPLETED || 325 !rsn_preauth_key_mgmt(sm->key_mgmt)) { 326 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable " 327 "state for new pre-authentication"); 328 return; /* invalid state for new pre-auth */ 329 } 330 331 dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates, 332 struct rsn_pmksa_candidate, list) { 333 struct rsn_pmksa_cache_entry *p = NULL; 334 p = pmksa_cache_get(sm->pmksa, candidate->bssid, sm->own_addr, 335 NULL, NULL, 0); 336 if (!ether_addr_equal(sm->bssid, candidate->bssid) && 337 (p == NULL || p->opportunistic)) { 338 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA " 339 "candidate " MACSTR 340 " selected for pre-authentication", 341 MAC2STR(candidate->bssid)); 342 dl_list_del(&candidate->list); 343 rsn_preauth_init(sm, candidate->bssid, 344 sm->eap_conf_ctx); 345 os_free(candidate); 346 return; 347 } 348 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate " 349 MACSTR " does not need pre-authentication anymore", 350 MAC2STR(candidate->bssid)); 351 /* Some drivers (e.g., NDIS) expect to get notified about the 352 * PMKIDs again, so report the existing data now. */ 353 if (p) { 354 wpa_sm_add_pmkid(sm, NULL, candidate->bssid, p->pmkid, 355 NULL, p->pmk, p->pmk_len, 0, 0, 356 p->akmp); 357 } 358 359 dl_list_del(&candidate->list); 360 os_free(candidate); 361 } 362 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA " 363 "candidates"); 364 } 365 366 367 /** 368 * pmksa_candidate_add - Add a new PMKSA candidate 369 * @sm: Pointer to WPA state machine data from wpa_sm_init() 370 * @bssid: BSSID (authenticator address) of the candidate 371 * @prio: Priority (the smaller number, the higher priority) 372 * @preauth: Whether the candidate AP advertises support for pre-authentication 373 * 374 * This function is used to add PMKSA candidates for RSN pre-authentication. It 375 * is called from scan result processing and from driver events for PMKSA 376 * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event(). 377 */ pmksa_candidate_add(struct wpa_sm * sm,const u8 * bssid,int prio,int preauth)378 void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid, 379 int prio, int preauth) 380 { 381 struct rsn_pmksa_candidate *cand, *pos; 382 383 if (sm->network_ctx && sm->proactive_key_caching) 384 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx, 385 bssid, 0); 386 387 if (!preauth) { 388 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without " 389 "preauth flag"); 390 return; 391 } 392 393 /* If BSSID already on candidate list, update the priority of the old 394 * entry. Do not override priority based on normal scan results. */ 395 cand = NULL; 396 dl_list_for_each(pos, &sm->pmksa_candidates, 397 struct rsn_pmksa_candidate, list) { 398 if (ether_addr_equal(pos->bssid, bssid)) { 399 cand = pos; 400 break; 401 } 402 } 403 404 if (cand) { 405 dl_list_del(&cand->list); 406 if (prio < PMKID_CANDIDATE_PRIO_SCAN) 407 cand->priority = prio; 408 } else { 409 cand = os_zalloc(sizeof(*cand)); 410 if (cand == NULL) 411 return; 412 os_memcpy(cand->bssid, bssid, ETH_ALEN); 413 cand->priority = prio; 414 } 415 416 /* Add candidate to the list; order by increasing priority value. i.e., 417 * highest priority (smallest value) first. */ 418 dl_list_for_each(pos, &sm->pmksa_candidates, 419 struct rsn_pmksa_candidate, list) { 420 if (cand->priority <= pos->priority) { 421 if (!pos->list.prev) { 422 /* 423 * This cannot really happen in pracrice since 424 * pos was fetched from the list and the prev 425 * pointer must be set. It looks like clang 426 * static analyzer gets confused with the 427 * dl_list_del(&cand->list) call above and ends 428 * up assuming pos->list.prev could be NULL. 429 */ 430 os_free(cand); 431 return; 432 } 433 dl_list_add(pos->list.prev, &cand->list); 434 cand = NULL; 435 break; 436 } 437 } 438 if (cand) 439 dl_list_add_tail(&sm->pmksa_candidates, &cand->list); 440 441 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache " 442 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio); 443 rsn_preauth_candidate_process(sm); 444 } 445 446 447 /* TODO: schedule periodic scans if current AP supports preauth */ 448 449 /** 450 * rsn_preauth_scan_results - Start processing scan results for canditates 451 * @sm: Pointer to WPA state machine data from wpa_sm_init() 452 * Returns: 0 if ready to process results or -1 to skip processing 453 * 454 * This functions is used to notify RSN code about start of new scan results 455 * processing. The actual scan results will be provided by calling 456 * rsn_preauth_scan_result() for each BSS if this function returned 0. 457 */ rsn_preauth_scan_results(struct wpa_sm * sm)458 int rsn_preauth_scan_results(struct wpa_sm *sm) 459 { 460 if (sm->ssid_len == 0) 461 return -1; 462 463 /* 464 * TODO: is it ok to free all candidates? What about the entries 465 * received from EVENT_PMKID_CANDIDATE? 466 */ 467 pmksa_candidate_free(sm); 468 469 return 0; 470 } 471 472 473 /** 474 * rsn_preauth_scan_result - Processing scan result for PMKSA canditates 475 * @sm: Pointer to WPA state machine data from wpa_sm_init() 476 * 477 * Add all suitable APs (Authenticators) from scan results into PMKSA 478 * candidate list. 479 */ rsn_preauth_scan_result(struct wpa_sm * sm,const u8 * bssid,const u8 * ssid,const u8 * rsn)480 void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid, 481 const u8 *ssid, const u8 *rsn) 482 { 483 struct wpa_ie_data ie; 484 struct rsn_pmksa_cache_entry *pmksa; 485 486 if (ssid[1] != sm->ssid_len || 487 os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0) 488 return; /* Not for the current SSID */ 489 490 if (ether_addr_equal(bssid, sm->bssid)) 491 return; /* Ignore current AP */ 492 493 if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie)) 494 return; 495 496 pmksa = pmksa_cache_get(sm->pmksa, bssid, sm->own_addr, NULL, NULL, 0); 497 if (pmksa && (!pmksa->opportunistic || 498 !(ie.capabilities & WPA_CAPABILITY_PREAUTH))) 499 return; 500 501 if (!rsn_preauth_key_mgmt(ie.key_mgmt)) 502 return; 503 504 /* Give less priority to candidates found from normal scan results. */ 505 pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN, 506 ie.capabilities & WPA_CAPABILITY_PREAUTH); 507 } 508 509 510 #ifdef CONFIG_CTRL_IFACE 511 /** 512 * rsn_preauth_get_status - Get pre-authentication status 513 * @sm: Pointer to WPA state machine data from wpa_sm_init() 514 * @buf: Buffer for status information 515 * @buflen: Maximum buffer length 516 * @verbose: Whether to include verbose status information 517 * Returns: Number of bytes written to buf. 518 * 519 * Query WPA2 pre-authentication for status information. This function fills in 520 * a text area with current status information. If the buffer (buf) is not 521 * large enough, status information will be truncated to fit the buffer. 522 */ rsn_preauth_get_status(struct wpa_sm * sm,char * buf,size_t buflen,int verbose)523 int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen, 524 int verbose) 525 { 526 char *pos = buf, *end = buf + buflen; 527 int res, ret; 528 529 if (sm->preauth_eapol) { 530 ret = os_snprintf(pos, end - pos, "Pre-authentication " 531 "EAPOL state machines:\n"); 532 if (os_snprintf_error(end - pos, ret)) 533 return pos - buf; 534 pos += ret; 535 res = eapol_sm_get_status(sm->preauth_eapol, 536 pos, end - pos, verbose); 537 if (res >= 0) 538 pos += res; 539 } 540 541 return pos - buf; 542 } 543 #endif /* CONFIG_CTRL_IFACE */ 544 545 546 /** 547 * rsn_preauth_in_progress - Verify whether pre-authentication is in progress 548 * @sm: Pointer to WPA state machine data from wpa_sm_init() 549 */ rsn_preauth_in_progress(struct wpa_sm * sm)550 int rsn_preauth_in_progress(struct wpa_sm *sm) 551 { 552 return sm->preauth_eapol != NULL; 553 } 554 555 #endif /* IEEE8021X_EAPOL && !CONFIG_NO_WPA */ 556