preauth.c revision 1f69aa52ea2e0a73ac502565df8c666ee49cab6a
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 26 27#if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2) 28 29#define PMKID_CANDIDATE_PRIO_SCAN 1000 30 31 32struct rsn_pmksa_candidate { 33 struct dl_list list; 34 u8 bssid[ETH_ALEN]; 35 int priority; 36}; 37 38 39/** 40 * pmksa_candidate_free - Free all entries in PMKSA candidate list 41 * @sm: Pointer to WPA state machine data from wpa_sm_init() 42 */ 43void pmksa_candidate_free(struct wpa_sm *sm) 44{ 45 struct rsn_pmksa_candidate *entry, *n; 46 47 if (sm == NULL) 48 return; 49 50 dl_list_for_each_safe(entry, n, &sm->pmksa_candidates, 51 struct rsn_pmksa_candidate, list) { 52 dl_list_del(&entry->list); 53 os_free(entry); 54 } 55} 56 57 58static void rsn_preauth_receive(void *ctx, const u8 *src_addr, 59 const u8 *buf, size_t len) 60{ 61 struct wpa_sm *sm = ctx; 62 63 wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr)); 64 wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len); 65 66 if (sm->preauth_eapol == NULL || 67 is_zero_ether_addr(sm->preauth_bssid) || 68 os_memcmp(sm->preauth_bssid, src_addr, ETH_ALEN) != 0) { 69 wpa_printf(MSG_WARNING, "RSN pre-auth frame received from " 70 "unexpected source " MACSTR " - dropped", 71 MAC2STR(src_addr)); 72 return; 73 } 74 75 eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len); 76} 77 78 79static void rsn_preauth_eapol_cb(struct eapol_sm *eapol, int success, 80 void *ctx) 81{ 82 struct wpa_sm *sm = ctx; 83 u8 pmk[PMK_LEN]; 84 85 if (success) { 86 int res, pmk_len; 87 pmk_len = PMK_LEN; 88 res = eapol_sm_get_key(eapol, pmk, PMK_LEN); 89 if (res) { 90 /* 91 * EAP-LEAP is an exception from other EAP methods: it 92 * uses only 16-byte PMK. 93 */ 94 res = eapol_sm_get_key(eapol, pmk, 16); 95 pmk_len = 16; 96 } 97 if (res == 0) { 98 wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth", 99 pmk, pmk_len); 100 sm->pmk_len = pmk_len; 101 pmksa_cache_add(sm->pmksa, pmk, pmk_len, 102 sm->preauth_bssid, sm->own_addr, 103 sm->network_ctx, 104 WPA_KEY_MGMT_IEEE8021X); 105 } else { 106 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, 107 "RSN: failed to get master session key from " 108 "pre-auth EAPOL state machines"); 109 success = 0; 110 } 111 } 112 113 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 114 MACSTR " %s", MAC2STR(sm->preauth_bssid), 115 success ? "completed successfully" : "failed"); 116 117 rsn_preauth_deinit(sm); 118 rsn_preauth_candidate_process(sm); 119} 120 121 122static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx) 123{ 124 struct wpa_sm *sm = eloop_ctx; 125 126 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 127 MACSTR " timed out", MAC2STR(sm->preauth_bssid)); 128 rsn_preauth_deinit(sm); 129 rsn_preauth_candidate_process(sm); 130} 131 132 133static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf, 134 size_t len) 135{ 136 struct wpa_sm *sm = ctx; 137 u8 *msg; 138 size_t msglen; 139 int res; 140 141 /* TODO: could add l2_packet_sendmsg that allows fragments to avoid 142 * extra copy here */ 143 144 if (sm->l2_preauth == NULL) 145 return -1; 146 147 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL); 148 if (msg == NULL) 149 return -1; 150 151 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen); 152 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid, 153 ETH_P_RSN_PREAUTH, msg, msglen); 154 os_free(msg); 155 return res; 156} 157 158 159/** 160 * rsn_preauth_init - Start new RSN pre-authentication 161 * @sm: Pointer to WPA state machine data from wpa_sm_init() 162 * @dst: Authenticator address (BSSID) with which to preauthenticate 163 * @eap_conf: Current EAP configuration 164 * Returns: 0 on success, -1 on another pre-authentication is in progress, 165 * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine 166 * initialization failure, -4 on memory allocation failure 167 * 168 * This function request an RSN pre-authentication with a given destination 169 * address. This is usually called for PMKSA candidates found from scan results 170 * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger 171 * pre-authentication. 172 */ 173int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst, 174 struct eap_peer_config *eap_conf) 175{ 176 struct eapol_config eapol_conf; 177 struct eapol_ctx *ctx; 178 179 if (sm->preauth_eapol) 180 return -1; 181 182 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, 183 "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst)); 184 185 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr, 186 ETH_P_RSN_PREAUTH, 187 rsn_preauth_receive, sm, 0); 188 if (sm->l2_preauth == NULL) { 189 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet " 190 "processing for pre-authentication"); 191 return -2; 192 } 193 194 if (sm->bridge_ifname) { 195 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname, 196 sm->own_addr, 197 ETH_P_RSN_PREAUTH, 198 rsn_preauth_receive, sm, 0); 199 if (sm->l2_preauth_br == NULL) { 200 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 " 201 "packet processing (bridge) for " 202 "pre-authentication"); 203 return -2; 204 } 205 } 206 207 ctx = os_zalloc(sizeof(*ctx)); 208 if (ctx == NULL) { 209 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context."); 210 return -4; 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 return -3; 229 } 230 os_memset(&eapol_conf, 0, sizeof(eapol_conf)); 231 eapol_conf.accept_802_1x_keys = 0; 232 eapol_conf.required_keys = 0; 233 eapol_conf.fast_reauth = sm->fast_reauth; 234 eapol_conf.workaround = sm->eap_workaround; 235 eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf); 236 /* 237 * Use a shorter startPeriod with preauthentication since the first 238 * preauth EAPOL-Start frame may end up being dropped due to race 239 * condition in the AP between the data receive and key configuration 240 * after the 4-Way Handshake. 241 */ 242 eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6); 243 os_memcpy(sm->preauth_bssid, dst, ETH_ALEN); 244 245 eapol_sm_notify_portValid(sm->preauth_eapol, TRUE); 246 /* 802.1X::portControl = Auto */ 247 eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE); 248 249 eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0, 250 rsn_preauth_timeout, sm, NULL); 251 252 return 0; 253} 254 255 256/** 257 * rsn_preauth_deinit - Abort RSN pre-authentication 258 * @sm: Pointer to WPA state machine data from wpa_sm_init() 259 * 260 * This function aborts the current RSN pre-authentication (if one is started) 261 * and frees resources allocated for it. 262 */ 263void rsn_preauth_deinit(struct wpa_sm *sm) 264{ 265 if (sm == NULL || !sm->preauth_eapol) 266 return; 267 268 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL); 269 eapol_sm_deinit(sm->preauth_eapol); 270 sm->preauth_eapol = NULL; 271 os_memset(sm->preauth_bssid, 0, ETH_ALEN); 272 273 l2_packet_deinit(sm->l2_preauth); 274 sm->l2_preauth = NULL; 275 if (sm->l2_preauth_br) { 276 l2_packet_deinit(sm->l2_preauth_br); 277 sm->l2_preauth_br = NULL; 278 } 279} 280 281 282/** 283 * rsn_preauth_candidate_process - Process PMKSA candidates 284 * @sm: Pointer to WPA state machine data from wpa_sm_init() 285 * 286 * Go through the PMKSA candidates and start pre-authentication if a candidate 287 * without an existing PMKSA cache entry is found. Processed candidates will be 288 * removed from the list. 289 */ 290void rsn_preauth_candidate_process(struct wpa_sm *sm) 291{ 292 struct rsn_pmksa_candidate *candidate, *n; 293 294 if (dl_list_empty(&sm->pmksa_candidates)) 295 return; 296 297 /* TODO: drop priority for old candidate entries */ 298 299 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate " 300 "list"); 301 if (sm->preauth_eapol || 302 sm->proto != WPA_PROTO_RSN || 303 wpa_sm_get_state(sm) != WPA_COMPLETED || 304 (sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X && 305 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256)) { 306 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable " 307 "state for new pre-authentication"); 308 return; /* invalid state for new pre-auth */ 309 } 310 311 dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates, 312 struct rsn_pmksa_candidate, list) { 313 struct rsn_pmksa_cache_entry *p = NULL; 314 p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL); 315 if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 && 316 (p == NULL || p->opportunistic)) { 317 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA " 318 "candidate " MACSTR 319 " selected for pre-authentication", 320 MAC2STR(candidate->bssid)); 321 dl_list_del(&candidate->list); 322 rsn_preauth_init(sm, candidate->bssid, 323 sm->eap_conf_ctx); 324 os_free(candidate); 325 return; 326 } 327 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate " 328 MACSTR " does not need pre-authentication anymore", 329 MAC2STR(candidate->bssid)); 330 /* Some drivers (e.g., NDIS) expect to get notified about the 331 * PMKIDs again, so report the existing data now. */ 332 if (p) { 333 wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid); 334 } 335 336 dl_list_del(&candidate->list); 337 os_free(candidate); 338 } 339 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA " 340 "candidates"); 341} 342 343 344/** 345 * pmksa_candidate_add - Add a new PMKSA candidate 346 * @sm: Pointer to WPA state machine data from wpa_sm_init() 347 * @bssid: BSSID (authenticator address) of the candidate 348 * @prio: Priority (the smaller number, the higher priority) 349 * @preauth: Whether the candidate AP advertises support for pre-authentication 350 * 351 * This function is used to add PMKSA candidates for RSN pre-authentication. It 352 * is called from scan result processing and from driver events for PMKSA 353 * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event(). 354 */ 355void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid, 356 int prio, int preauth) 357{ 358 struct rsn_pmksa_candidate *cand, *pos; 359 360 if (sm->network_ctx && sm->proactive_key_caching) 361 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx, 362 bssid); 363 364 if (!preauth) { 365 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without " 366 "preauth flag"); 367 return; 368 } 369 370 /* If BSSID already on candidate list, update the priority of the old 371 * entry. Do not override priority based on normal scan results. */ 372 cand = NULL; 373 dl_list_for_each(pos, &sm->pmksa_candidates, 374 struct rsn_pmksa_candidate, list) { 375 if (os_memcmp(pos->bssid, bssid, ETH_ALEN) == 0) { 376 cand = pos; 377 break; 378 } 379 } 380 381 if (cand) { 382 dl_list_del(&cand->list); 383 if (prio < PMKID_CANDIDATE_PRIO_SCAN) 384 cand->priority = prio; 385 } else { 386 cand = os_zalloc(sizeof(*cand)); 387 if (cand == NULL) 388 return; 389 os_memcpy(cand->bssid, bssid, ETH_ALEN); 390 cand->priority = prio; 391 } 392 393 /* Add candidate to the list; order by increasing priority value. i.e., 394 * highest priority (smallest value) first. */ 395 dl_list_for_each(pos, &sm->pmksa_candidates, 396 struct rsn_pmksa_candidate, list) { 397 if (cand->priority <= pos->priority) { 398 dl_list_add(pos->list.prev, &cand->list); 399 cand = NULL; 400 break; 401 } 402 } 403 if (cand) 404 dl_list_add_tail(&sm->pmksa_candidates, &cand->list); 405 406 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache " 407 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio); 408 rsn_preauth_candidate_process(sm); 409} 410 411 412/* TODO: schedule periodic scans if current AP supports preauth */ 413 414/** 415 * rsn_preauth_scan_results - Start processing scan results for canditates 416 * @sm: Pointer to WPA state machine data from wpa_sm_init() 417 * Returns: 0 if ready to process results or -1 to skip processing 418 * 419 * This functions is used to notify RSN code about start of new scan results 420 * processing. The actual scan results will be provided by calling 421 * rsn_preauth_scan_result() for each BSS if this function returned 0. 422 */ 423int rsn_preauth_scan_results(struct wpa_sm *sm) 424{ 425 if (sm->ssid_len == 0) 426 return -1; 427 428 /* 429 * TODO: is it ok to free all candidates? What about the entries 430 * received from EVENT_PMKID_CANDIDATE? 431 */ 432 pmksa_candidate_free(sm); 433 434 return 0; 435} 436 437 438/** 439 * rsn_preauth_scan_result - Processing scan result for PMKSA canditates 440 * @sm: Pointer to WPA state machine data from wpa_sm_init() 441 * 442 * Add all suitable APs (Authenticators) from scan results into PMKSA 443 * candidate list. 444 */ 445void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid, 446 const u8 *ssid, const u8 *rsn) 447{ 448 struct wpa_ie_data ie; 449 struct rsn_pmksa_cache_entry *pmksa; 450 451 if (ssid[1] != sm->ssid_len || 452 os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0) 453 return; /* Not for the current SSID */ 454 455 if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0) 456 return; /* Ignore current AP */ 457 458 if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie)) 459 return; 460 461 pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL); 462 if (pmksa && (!pmksa->opportunistic || 463 !(ie.capabilities & WPA_CAPABILITY_PREAUTH))) 464 return; 465 466 /* Give less priority to candidates found from normal scan results. */ 467 pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN, 468 ie.capabilities & WPA_CAPABILITY_PREAUTH); 469} 470 471 472#ifdef CONFIG_CTRL_IFACE 473/** 474 * rsn_preauth_get_status - Get pre-authentication status 475 * @sm: Pointer to WPA state machine data from wpa_sm_init() 476 * @buf: Buffer for status information 477 * @buflen: Maximum buffer length 478 * @verbose: Whether to include verbose status information 479 * Returns: Number of bytes written to buf. 480 * 481 * Query WPA2 pre-authentication for status information. This function fills in 482 * a text area with current status information. If the buffer (buf) is not 483 * large enough, status information will be truncated to fit the buffer. 484 */ 485int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen, 486 int verbose) 487{ 488 char *pos = buf, *end = buf + buflen; 489 int res, ret; 490 491 if (sm->preauth_eapol) { 492 ret = os_snprintf(pos, end - pos, "Pre-authentication " 493 "EAPOL state machines:\n"); 494 if (ret < 0 || ret >= end - pos) 495 return pos - buf; 496 pos += ret; 497 res = eapol_sm_get_status(sm->preauth_eapol, 498 pos, end - pos, verbose); 499 if (res >= 0) 500 pos += res; 501 } 502 503 return pos - buf; 504} 505#endif /* CONFIG_CTRL_IFACE */ 506 507 508/** 509 * rsn_preauth_in_progress - Verify whether pre-authentication is in progress 510 * @sm: Pointer to WPA state machine data from wpa_sm_init() 511 */ 512int rsn_preauth_in_progress(struct wpa_sm *sm) 513{ 514 return sm->preauth_eapol != NULL; 515} 516 517#endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */ 518