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 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2) 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, int success, 74 void *ctx) 75 { 76 struct wpa_sm *sm = ctx; 77 u8 pmk[PMK_LEN]; 78 79 if (success) { 80 int res, pmk_len; 81 pmk_len = PMK_LEN; 82 res = eapol_sm_get_key(eapol, pmk, PMK_LEN); 83 if (res) { 84 /* 85 * EAP-LEAP is an exception from other EAP methods: it 86 * uses only 16-byte PMK. 87 */ 88 res = eapol_sm_get_key(eapol, pmk, 16); 89 pmk_len = 16; 90 } 91 if (res == 0) { 92 wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth", 93 pmk, pmk_len); 94 sm->pmk_len = pmk_len; 95 pmksa_cache_add(sm->pmksa, pmk, pmk_len, 96 sm->preauth_bssid, sm->own_addr, 97 sm->network_ctx, 98 WPA_KEY_MGMT_IEEE8021X); 99 } else { 100 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, 101 "RSN: failed to get master session key from " 102 "pre-auth EAPOL state machines"); 103 success = 0; 104 } 105 } 106 107 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 108 MACSTR " %s", MAC2STR(sm->preauth_bssid), 109 success ? "completed successfully" : "failed"); 110 111 rsn_preauth_deinit(sm); 112 rsn_preauth_candidate_process(sm); 113 } 114 115 116 static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx) 117 { 118 struct wpa_sm *sm = eloop_ctx; 119 120 wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with " 121 MACSTR " timed out", MAC2STR(sm->preauth_bssid)); 122 rsn_preauth_deinit(sm); 123 rsn_preauth_candidate_process(sm); 124 } 125 126 127 static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf, 128 size_t len) 129 { 130 struct wpa_sm *sm = ctx; 131 u8 *msg; 132 size_t msglen; 133 int res; 134 135 /* TODO: could add l2_packet_sendmsg that allows fragments to avoid 136 * extra copy here */ 137 138 if (sm->l2_preauth == NULL) 139 return -1; 140 141 msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL); 142 if (msg == NULL) 143 return -1; 144 145 wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen); 146 res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid, 147 ETH_P_RSN_PREAUTH, msg, msglen); 148 os_free(msg); 149 return res; 150 } 151 152 153 /** 154 * rsn_preauth_init - Start new RSN pre-authentication 155 * @sm: Pointer to WPA state machine data from wpa_sm_init() 156 * @dst: Authenticator address (BSSID) with which to preauthenticate 157 * @eap_conf: Current EAP configuration 158 * Returns: 0 on success, -1 on another pre-authentication is in progress, 159 * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine 160 * initialization failure, -4 on memory allocation failure 161 * 162 * This function request an RSN pre-authentication with a given destination 163 * address. This is usually called for PMKSA candidates found from scan results 164 * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger 165 * pre-authentication. 166 */ 167 int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst, 168 struct eap_peer_config *eap_conf) 169 { 170 struct eapol_config eapol_conf; 171 struct eapol_ctx *ctx; 172 173 if (sm->preauth_eapol) 174 return -1; 175 176 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, 177 "RSN: starting pre-authentication with " MACSTR, MAC2STR(dst)); 178 179 sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr, 180 ETH_P_RSN_PREAUTH, 181 rsn_preauth_receive, sm, 0); 182 if (sm->l2_preauth == NULL) { 183 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet " 184 "processing for pre-authentication"); 185 return -2; 186 } 187 188 if (sm->bridge_ifname) { 189 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname, 190 sm->own_addr, 191 ETH_P_RSN_PREAUTH, 192 rsn_preauth_receive, sm, 0); 193 if (sm->l2_preauth_br == NULL) { 194 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 " 195 "packet processing (bridge) for " 196 "pre-authentication"); 197 return -2; 198 } 199 } 200 201 ctx = os_zalloc(sizeof(*ctx)); 202 if (ctx == NULL) { 203 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context."); 204 return -4; 205 } 206 ctx->ctx = sm->ctx->ctx; 207 ctx->msg_ctx = sm->ctx->ctx; 208 ctx->preauth = 1; 209 ctx->cb = rsn_preauth_eapol_cb; 210 ctx->cb_ctx = sm; 211 ctx->scard_ctx = sm->scard_ctx; 212 ctx->eapol_send = rsn_preauth_eapol_send; 213 ctx->eapol_send_ctx = sm; 214 ctx->set_config_blob = sm->ctx->set_config_blob; 215 ctx->get_config_blob = sm->ctx->get_config_blob; 216 217 sm->preauth_eapol = eapol_sm_init(ctx); 218 if (sm->preauth_eapol == NULL) { 219 os_free(ctx); 220 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL " 221 "state machines for pre-authentication"); 222 return -3; 223 } 224 os_memset(&eapol_conf, 0, sizeof(eapol_conf)); 225 eapol_conf.accept_802_1x_keys = 0; 226 eapol_conf.required_keys = 0; 227 eapol_conf.fast_reauth = sm->fast_reauth; 228 eapol_conf.workaround = sm->eap_workaround; 229 eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf); 230 /* 231 * Use a shorter startPeriod with preauthentication since the first 232 * preauth EAPOL-Start frame may end up being dropped due to race 233 * condition in the AP between the data receive and key configuration 234 * after the 4-Way Handshake. 235 */ 236 eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6); 237 os_memcpy(sm->preauth_bssid, dst, ETH_ALEN); 238 239 eapol_sm_notify_portValid(sm->preauth_eapol, TRUE); 240 /* 802.1X::portControl = Auto */ 241 eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE); 242 243 eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0, 244 rsn_preauth_timeout, sm, NULL); 245 246 return 0; 247 } 248 249 250 /** 251 * rsn_preauth_deinit - Abort RSN pre-authentication 252 * @sm: Pointer to WPA state machine data from wpa_sm_init() 253 * 254 * This function aborts the current RSN pre-authentication (if one is started) 255 * and frees resources allocated for it. 256 */ 257 void rsn_preauth_deinit(struct wpa_sm *sm) 258 { 259 if (sm == NULL || !sm->preauth_eapol) 260 return; 261 262 eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL); 263 eapol_sm_deinit(sm->preauth_eapol); 264 sm->preauth_eapol = NULL; 265 os_memset(sm->preauth_bssid, 0, ETH_ALEN); 266 267 l2_packet_deinit(sm->l2_preauth); 268 sm->l2_preauth = NULL; 269 if (sm->l2_preauth_br) { 270 l2_packet_deinit(sm->l2_preauth_br); 271 sm->l2_preauth_br = NULL; 272 } 273 } 274 275 276 /** 277 * rsn_preauth_candidate_process - Process PMKSA candidates 278 * @sm: Pointer to WPA state machine data from wpa_sm_init() 279 * 280 * Go through the PMKSA candidates and start pre-authentication if a candidate 281 * without an existing PMKSA cache entry is found. Processed candidates will be 282 * removed from the list. 283 */ 284 void rsn_preauth_candidate_process(struct wpa_sm *sm) 285 { 286 struct rsn_pmksa_candidate *candidate, *n; 287 288 if (dl_list_empty(&sm->pmksa_candidates)) 289 return; 290 291 /* TODO: drop priority for old candidate entries */ 292 293 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate " 294 "list"); 295 if (sm->preauth_eapol || 296 sm->proto != WPA_PROTO_RSN || 297 wpa_sm_get_state(sm) != WPA_COMPLETED || 298 (sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X && 299 sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256)) { 300 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable " 301 "state for new pre-authentication"); 302 return; /* invalid state for new pre-auth */ 303 } 304 305 dl_list_for_each_safe(candidate, n, &sm->pmksa_candidates, 306 struct rsn_pmksa_candidate, list) { 307 struct rsn_pmksa_cache_entry *p = NULL; 308 p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL, NULL); 309 if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 && 310 (p == NULL || p->opportunistic)) { 311 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA " 312 "candidate " MACSTR 313 " selected for pre-authentication", 314 MAC2STR(candidate->bssid)); 315 dl_list_del(&candidate->list); 316 rsn_preauth_init(sm, candidate->bssid, 317 sm->eap_conf_ctx); 318 os_free(candidate); 319 return; 320 } 321 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate " 322 MACSTR " does not need pre-authentication anymore", 323 MAC2STR(candidate->bssid)); 324 /* Some drivers (e.g., NDIS) expect to get notified about the 325 * PMKIDs again, so report the existing data now. */ 326 if (p) { 327 wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid); 328 } 329 330 dl_list_del(&candidate->list); 331 os_free(candidate); 332 } 333 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA " 334 "candidates"); 335 } 336 337 338 /** 339 * pmksa_candidate_add - Add a new PMKSA candidate 340 * @sm: Pointer to WPA state machine data from wpa_sm_init() 341 * @bssid: BSSID (authenticator address) of the candidate 342 * @prio: Priority (the smaller number, the higher priority) 343 * @preauth: Whether the candidate AP advertises support for pre-authentication 344 * 345 * This function is used to add PMKSA candidates for RSN pre-authentication. It 346 * is called from scan result processing and from driver events for PMKSA 347 * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event(). 348 */ 349 void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid, 350 int prio, int preauth) 351 { 352 struct rsn_pmksa_candidate *cand, *pos; 353 354 if (sm->network_ctx && sm->proactive_key_caching) 355 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx, 356 bssid); 357 358 if (!preauth) { 359 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without " 360 "preauth flag"); 361 return; 362 } 363 364 /* If BSSID already on candidate list, update the priority of the old 365 * entry. Do not override priority based on normal scan results. */ 366 cand = NULL; 367 dl_list_for_each(pos, &sm->pmksa_candidates, 368 struct rsn_pmksa_candidate, list) { 369 if (os_memcmp(pos->bssid, bssid, ETH_ALEN) == 0) { 370 cand = pos; 371 break; 372 } 373 } 374 375 if (cand) { 376 dl_list_del(&cand->list); 377 if (prio < PMKID_CANDIDATE_PRIO_SCAN) 378 cand->priority = prio; 379 } else { 380 cand = os_zalloc(sizeof(*cand)); 381 if (cand == NULL) 382 return; 383 os_memcpy(cand->bssid, bssid, ETH_ALEN); 384 cand->priority = prio; 385 } 386 387 /* Add candidate to the list; order by increasing priority value. i.e., 388 * highest priority (smallest value) first. */ 389 dl_list_for_each(pos, &sm->pmksa_candidates, 390 struct rsn_pmksa_candidate, list) { 391 if (cand->priority <= pos->priority) { 392 dl_list_add(pos->list.prev, &cand->list); 393 cand = NULL; 394 break; 395 } 396 } 397 if (cand) 398 dl_list_add_tail(&sm->pmksa_candidates, &cand->list); 399 400 wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache " 401 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio); 402 rsn_preauth_candidate_process(sm); 403 } 404 405 406 /* TODO: schedule periodic scans if current AP supports preauth */ 407 408 /** 409 * rsn_preauth_scan_results - Start processing scan results for canditates 410 * @sm: Pointer to WPA state machine data from wpa_sm_init() 411 * Returns: 0 if ready to process results or -1 to skip processing 412 * 413 * This functions is used to notify RSN code about start of new scan results 414 * processing. The actual scan results will be provided by calling 415 * rsn_preauth_scan_result() for each BSS if this function returned 0. 416 */ 417 int rsn_preauth_scan_results(struct wpa_sm *sm) 418 { 419 if (sm->ssid_len == 0) 420 return -1; 421 422 /* 423 * TODO: is it ok to free all candidates? What about the entries 424 * received from EVENT_PMKID_CANDIDATE? 425 */ 426 pmksa_candidate_free(sm); 427 428 return 0; 429 } 430 431 432 /** 433 * rsn_preauth_scan_result - Processing scan result for PMKSA canditates 434 * @sm: Pointer to WPA state machine data from wpa_sm_init() 435 * 436 * Add all suitable APs (Authenticators) from scan results into PMKSA 437 * candidate list. 438 */ 439 void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid, 440 const u8 *ssid, const u8 *rsn) 441 { 442 struct wpa_ie_data ie; 443 struct rsn_pmksa_cache_entry *pmksa; 444 445 if (ssid[1] != sm->ssid_len || 446 os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0) 447 return; /* Not for the current SSID */ 448 449 if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0) 450 return; /* Ignore current AP */ 451 452 if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie)) 453 return; 454 455 pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL, NULL); 456 if (pmksa && (!pmksa->opportunistic || 457 !(ie.capabilities & WPA_CAPABILITY_PREAUTH))) 458 return; 459 460 /* Give less priority to candidates found from normal scan results. */ 461 pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN, 462 ie.capabilities & WPA_CAPABILITY_PREAUTH); 463 } 464 465 466 #ifdef CONFIG_CTRL_IFACE 467 /** 468 * rsn_preauth_get_status - Get pre-authentication status 469 * @sm: Pointer to WPA state machine data from wpa_sm_init() 470 * @buf: Buffer for status information 471 * @buflen: Maximum buffer length 472 * @verbose: Whether to include verbose status information 473 * Returns: Number of bytes written to buf. 474 * 475 * Query WPA2 pre-authentication for status information. This function fills in 476 * a text area with current status information. If the buffer (buf) is not 477 * large enough, status information will be truncated to fit the buffer. 478 */ 479 int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen, 480 int verbose) 481 { 482 char *pos = buf, *end = buf + buflen; 483 int res, ret; 484 485 if (sm->preauth_eapol) { 486 ret = os_snprintf(pos, end - pos, "Pre-authentication " 487 "EAPOL state machines:\n"); 488 if (ret < 0 || ret >= end - pos) 489 return pos - buf; 490 pos += ret; 491 res = eapol_sm_get_status(sm->preauth_eapol, 492 pos, end - pos, verbose); 493 if (res >= 0) 494 pos += res; 495 } 496 497 return pos - buf; 498 } 499 #endif /* CONFIG_CTRL_IFACE */ 500 501 502 /** 503 * rsn_preauth_in_progress - Verify whether pre-authentication is in progress 504 * @sm: Pointer to WPA state machine data from wpa_sm_init() 505 */ 506 int rsn_preauth_in_progress(struct wpa_sm *sm) 507 { 508 return sm->preauth_eapol != NULL; 509 } 510 511 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */ 512
