1/* 2 * RSN pre-authentication (supplicant) 3 * Copyright (c) 2003-2010, Jouni Malinen <j@w1.fi> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * Alternatively, this software may be distributed under the terms of BSD 10 * license. 11 * 12 * See README and COPYING for more details. 13 */ 14 15#include "includes.h" 16 17#include "common.h" 18#include "wpa.h" 19#include "eloop.h" 20#include "l2_packet/l2_packet.h" 21#include "eapol_supp/eapol_supp_sm.h" 22#include "preauth.h" 23#include "pmksa_cache.h" 24#include "wpa_i.h" 25#include "common/ieee802_11_defs.h" 26 27 28#if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2) 29 30#define PMKID_CANDIDATE_PRIO_SCAN 1000 31 32 33struct rsn_pmksa_candidate { 34 struct dl_list list; 35 u8 bssid[ETH_ALEN]; 36 int priority; 37}; 38 39 40/** 41 * pmksa_candidate_free - Free all entries in PMKSA candidate list 42 * @sm: Pointer to WPA state machine data from wpa_sm_init() 43 */ 44void pmksa_candidate_free(struct wpa_sm *sm) 45{ 46 struct rsn_pmksa_candidate *entry, *n; 47 48 if (sm == NULL) 49 return; 50 51 dl_list_for_each_safe(entry, n, &sm->pmksa_candidates, 52 struct rsn_pmksa_candidate, list) { 53 dl_list_del(&entry->list); 54 os_free(entry); 55 } 56} 57 58 59static void rsn_preauth_receive(void *ctx, const u8 *src_addr, 60 const u8 *buf, size_t len) 61{ 62 struct wpa_sm *sm = ctx; 63 64 wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr)); 65 wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len); 66 67 if (sm->preauth_eapol == NULL || 68 is_zero_ether_addr(sm->preauth_bssid) || 69 os_memcmp(sm->preauth_bssid, src_addr, ETH_ALEN) != 0) { 70 wpa_printf(MSG_WARNING, "RSN pre-auth frame received from " 71 "unexpected source " MACSTR " - dropped", 72 MAC2STR(src_addr)); 73 return; 74 } 75 76 eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len); 77} 78 79 80static void rsn_preauth_eapol_cb(struct eapol_sm *eapol, int success, 81 void *ctx) 82{ 83 struct wpa_sm *sm = ctx; 84 u8 pmk[PMK_LEN]; 85 86 if (success) { 87 int res, pmk_len; 88 pmk_len = PMK_LEN; 89 res = eapol_sm_get_key(eapol, pmk, PMK_LEN); 90 if (res) { 91 /* 92 * EAP-LEAP is an exception from other EAP methods: it 93 * uses only 16-byte PMK. 94 */ 95 res = eapol_sm_get_key(eapol, pmk, 16); 96 pmk_len = 16; 97 } 98 if (res == 0) { 99 wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth", 100 pmk, pmk_len); 101 sm->pmk_len = pmk_len; 102 pmksa_cache_add(sm->pmksa, pmk, pmk_len, 103 sm->preauth_bssid, sm->own_addr, 104 sm->network_ctx, 105 WPA_KEY_MGMT_IEEE8021X); 106 } else { 107 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, 108 "RSN: failed to get master session key from " 109 "pre-auth EAPOL state machines"); 110 success = 0; 111 } 112 } 113 114 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 115 MACSTR " %s", MAC2STR(sm->preauth_bssid), 116 success ? "completed successfully" : "failed"); 117 118 rsn_preauth_deinit(sm); 119 rsn_preauth_candidate_process(sm); 120} 121 122 123static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx) 124{ 125 struct wpa_sm *sm = eloop_ctx; 126 127 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 128 MACSTR " timed out", MAC2STR(sm->preauth_bssid)); 129 rsn_preauth_deinit(sm); 130 rsn_preauth_candidate_process(sm); 131} 132 133 134static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf, 135 size_t len) 136{ 137 struct wpa_sm *sm = ctx; 138 u8 *msg; 139 size_t msglen; 140 int res; 141 142 /* TODO: could add l2_packet_sendmsg that allows fragments to avoid 143 * extra copy here */ 144 145 if (sm->l2_preauth == NULL) 146 return -1; 147 148 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL); 149 if (msg == NULL) 150 return -1; 151 152 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen); 153 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid, 154 ETH_P_RSN_PREAUTH, msg, msglen); 155 os_free(msg); 156 return res; 157} 158 159 160/** 161 * rsn_preauth_init - Start new RSN pre-authentication 162 * @sm: Pointer to WPA state machine data from wpa_sm_init() 163 * @dst: Authenticator address (BSSID) with which to preauthenticate 164 * @eap_conf: Current EAP configuration 165 * Returns: 0 on success, -1 on another pre-authentication is in progress, 166 * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine 167 * initialization failure, -4 on memory allocation failure 168 * 169 * This function request an RSN pre-authentication with a given destination 170 * address. This is usually called for PMKSA candidates found from scan results 171 * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger 172 * pre-authentication. 173 */ 174int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst, 175 struct eap_peer_config *eap_conf) 176{ 177 struct eapol_config eapol_conf; 178 struct eapol_ctx *ctx; 179 180 if (sm->preauth_eapol) 181 return -1; 182 183 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, 184 "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst)); 185 186 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr, 187 ETH_P_RSN_PREAUTH, 188 rsn_preauth_receive, sm, 0); 189 if (sm->l2_preauth == NULL) { 190 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet " 191 "processing for pre-authentication"); 192 return -2; 193 } 194 195 if (sm->bridge_ifname) { 196 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname, 197 sm->own_addr, 198 ETH_P_RSN_PREAUTH, 199 rsn_preauth_receive, sm, 0); 200 if (sm->l2_preauth_br == NULL) { 201 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 " 202 "packet processing (bridge) for " 203 "pre-authentication"); 204 return -2; 205 } 206 } 207 208 ctx = os_zalloc(sizeof(*ctx)); 209 if (ctx == NULL) { 210 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context."); 211 return -4; 212 } 213 ctx->ctx = sm->ctx->ctx; 214 ctx->msg_ctx = sm->ctx->ctx; 215 ctx->preauth = 1; 216 ctx->cb = rsn_preauth_eapol_cb; 217 ctx->cb_ctx = sm; 218 ctx->scard_ctx = sm->scard_ctx; 219 ctx->eapol_send = rsn_preauth_eapol_send; 220 ctx->eapol_send_ctx = sm; 221 ctx->set_config_blob = sm->ctx->set_config_blob; 222 ctx->get_config_blob = sm->ctx->get_config_blob; 223 224 sm->preauth_eapol = eapol_sm_init(ctx); 225 if (sm->preauth_eapol == NULL) { 226 os_free(ctx); 227 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL " 228 "state machines for pre-authentication"); 229 return -3; 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} 255 256 257/** 258 * rsn_preauth_deinit - Abort RSN pre-authentication 259 * @sm: Pointer to WPA state machine data from wpa_sm_init() 260 * 261 * This function aborts the current RSN pre-authentication (if one is started) 262 * and frees resources allocated for it. 263 */ 264void rsn_preauth_deinit(struct wpa_sm *sm) 265{ 266 if (sm == NULL || !sm->preauth_eapol) 267 return; 268 269 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL); 270 eapol_sm_deinit(sm->preauth_eapol); 271 sm->preauth_eapol = NULL; 272 os_memset(sm->preauth_bssid, 0, ETH_ALEN); 273 274 l2_packet_deinit(sm->l2_preauth); 275 sm->l2_preauth = NULL; 276 if (sm->l2_preauth_br) { 277 l2_packet_deinit(sm->l2_preauth_br); 278 sm->l2_preauth_br = NULL; 279 } 280} 281 282 283/** 284 * rsn_preauth_candidate_process - Process PMKSA candidates 285 * @sm: Pointer to WPA state machine data from wpa_sm_init() 286 * 287 * Go through the PMKSA candidates and start pre-authentication if a candidate 288 * without an existing PMKSA cache entry is found. Processed candidates will be 289 * removed from the list. 290 */ 291void rsn_preauth_candidate_process(struct wpa_sm *sm) 292{ 293 struct rsn_pmksa_candidate *candidate, *n; 294 295 if (dl_list_empty(&sm->pmksa_candidates)) 296 return; 297 298 /* TODO: drop priority for old candidate entries */ 299 300 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate " 301 "list"); 302 if (sm->preauth_eapol || 303 sm->proto != WPA_PROTO_RSN || 304 wpa_sm_get_state(sm) != WPA_COMPLETED || 305 (sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X && 306 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256)) { 307 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable " 308 "state for new pre-authentication"); 309 return; /* invalid state for new pre-auth */ 310 } 311 312 dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates, 313 struct rsn_pmksa_candidate, list) { 314 struct rsn_pmksa_cache_entry *p = NULL; 315 p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL); 316 if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 && 317 (p == NULL || p->opportunistic)) { 318 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA " 319 "candidate " MACSTR 320 " selected for pre-authentication", 321 MAC2STR(candidate->bssid)); 322 dl_list_del(&candidate->list); 323 rsn_preauth_init(sm, candidate->bssid, 324 sm->eap_conf_ctx); 325 os_free(candidate); 326 return; 327 } 328 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate " 329 MACSTR " does not need pre-authentication anymore", 330 MAC2STR(candidate->bssid)); 331 /* Some drivers (e.g., NDIS) expect to get notified about the 332 * PMKIDs again, so report the existing data now. */ 333 if (p) { 334 wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid); 335 } 336 337 dl_list_del(&candidate->list); 338 os_free(candidate); 339 } 340 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA " 341 "candidates"); 342} 343 344 345/** 346 * pmksa_candidate_add - Add a new PMKSA candidate 347 * @sm: Pointer to WPA state machine data from wpa_sm_init() 348 * @bssid: BSSID (authenticator address) of the candidate 349 * @prio: Priority (the smaller number, the higher priority) 350 * @preauth: Whether the candidate AP advertises support for pre-authentication 351 * 352 * This function is used to add PMKSA candidates for RSN pre-authentication. It 353 * is called from scan result processing and from driver events for PMKSA 354 * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event(). 355 */ 356void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid, 357 int prio, int preauth) 358{ 359 struct rsn_pmksa_candidate *cand, *pos; 360 361 if (sm->network_ctx && sm->proactive_key_caching) 362 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx, 363 bssid); 364 365 if (!preauth) { 366 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without " 367 "preauth flag"); 368 return; 369 } 370 371 /* If BSSID already on candidate list, update the priority of the old 372 * entry. Do not override priority based on normal scan results. */ 373 cand = NULL; 374 dl_list_for_each(pos, &sm->pmksa_candidates, 375 struct rsn_pmksa_candidate, list) { 376 if (os_memcmp(pos->bssid, bssid, ETH_ALEN) == 0) { 377 cand = pos; 378 break; 379 } 380 } 381 382 if (cand) { 383 dl_list_del(&cand->list); 384 if (prio < PMKID_CANDIDATE_PRIO_SCAN) 385 cand->priority = prio; 386 } else { 387 cand = os_zalloc(sizeof(*cand)); 388 if (cand == NULL) 389 return; 390 os_memcpy(cand->bssid, bssid, ETH_ALEN); 391 cand->priority = prio; 392 } 393 394 /* Add candidate to the list; order by increasing priority value. i.e., 395 * highest priority (smallest value) first. */ 396 dl_list_for_each(pos, &sm->pmksa_candidates, 397 struct rsn_pmksa_candidate, list) { 398 if (cand->priority <= pos->priority) { 399 dl_list_add(pos->list.prev, &cand->list); 400 cand = NULL; 401 break; 402 } 403 } 404 if (cand) 405 dl_list_add_tail(&sm->pmksa_candidates, &cand->list); 406 407 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache " 408 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio); 409 rsn_preauth_candidate_process(sm); 410} 411 412 413/* TODO: schedule periodic scans if current AP supports preauth */ 414 415/** 416 * rsn_preauth_scan_results - Start processing scan results for canditates 417 * @sm: Pointer to WPA state machine data from wpa_sm_init() 418 * Returns: 0 if ready to process results or -1 to skip processing 419 * 420 * This functions is used to notify RSN code about start of new scan results 421 * processing. The actual scan results will be provided by calling 422 * rsn_preauth_scan_result() for each BSS if this function returned 0. 423 */ 424int rsn_preauth_scan_results(struct wpa_sm *sm) 425{ 426 if (sm->ssid_len == 0) 427 return -1; 428 429 /* 430 * TODO: is it ok to free all candidates? What about the entries 431 * received from EVENT_PMKID_CANDIDATE? 432 */ 433 pmksa_candidate_free(sm); 434 435 return 0; 436} 437 438 439/** 440 * rsn_preauth_scan_result - Processing scan result for PMKSA canditates 441 * @sm: Pointer to WPA state machine data from wpa_sm_init() 442 * 443 * Add all suitable APs (Authenticators) from scan results into PMKSA 444 * candidate list. 445 */ 446void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid, 447 const u8 *ssid, const u8 *rsn) 448{ 449 struct wpa_ie_data ie; 450 struct rsn_pmksa_cache_entry *pmksa; 451 452 if (ssid[1] != sm->ssid_len || 453 os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0) 454 return; /* Not for the current SSID */ 455 456 if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0) 457 return; /* Ignore current AP */ 458 459 if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie)) 460 return; 461 462 pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL); 463 if (pmksa && (!pmksa->opportunistic || 464 !(ie.capabilities & WPA_CAPABILITY_PREAUTH))) 465 return; 466 467 /* Give less priority to candidates found from normal scan results. */ 468 pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN, 469 ie.capabilities & WPA_CAPABILITY_PREAUTH); 470} 471 472 473#ifdef CONFIG_CTRL_IFACE 474/** 475 * rsn_preauth_get_status - Get pre-authentication status 476 * @sm: Pointer to WPA state machine data from wpa_sm_init() 477 * @buf: Buffer for status information 478 * @buflen: Maximum buffer length 479 * @verbose: Whether to include verbose status information 480 * Returns: Number of bytes written to buf. 481 * 482 * Query WPA2 pre-authentication for status information. This function fills in 483 * a text area with current status information. If the buffer (buf) is not 484 * large enough, status information will be truncated to fit the buffer. 485 */ 486int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen, 487 int verbose) 488{ 489 char *pos = buf, *end = buf + buflen; 490 int res, ret; 491 492 if (sm->preauth_eapol) { 493 ret = os_snprintf(pos, end - pos, "Pre-authentication " 494 "EAPOL state machines:\n"); 495 if (ret < 0 || ret >= end - pos) 496 return pos - buf; 497 pos += ret; 498 res = eapol_sm_get_status(sm->preauth_eapol, 499 pos, end - pos, verbose); 500 if (res >= 0) 501 pos += res; 502 } 503 504 return pos - buf; 505} 506#endif /* CONFIG_CTRL_IFACE */ 507 508 509/** 510 * rsn_preauth_in_progress - Verify whether pre-authentication is in progress 511 * @sm: Pointer to WPA state machine data from wpa_sm_init() 512 */ 513int rsn_preauth_in_progress(struct wpa_sm *sm) 514{ 515 return sm->preauth_eapol != NULL; 516} 517 518#endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */ 519