git.maemo.org Git - wpasupplicant/blob - src/rsn_supp/preauth.c

   1 /*
   2  * WPA Supplicant - RSN pre-authentication
   3  * Copyright (c) 2003-2007, 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 "drivers/driver.h"
  20 #include "eloop.h"
  21 #include "l2_packet/l2_packet.h"
  22 #include "eapol_supp/eapol_supp_sm.h"
  23 #include "preauth.h"
  24 #include "pmksa_cache.h"
  25 #include "wpa_i.h"
  26 #include "ieee802_11_defs.h"
  27
  28
  29 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2)
  30
  31 #define PMKID_CANDIDATE_PRIO_SCAN 1000
  32
  33
  34 struct rsn_pmksa_candidate {
  35         struct rsn_pmksa_candidate *next;
  36         u8 bssid[ETH_ALEN];
  37         int priority;
  38 };
  39
  40
  41 /**
  42  * pmksa_candidate_free - Free all entries in PMKSA candidate list
  43  * @sm: Pointer to WPA state machine data from wpa_sm_init()
  44  */
  45 void pmksa_candidate_free(struct wpa_sm *sm)
  46 {
  47         struct rsn_pmksa_candidate *entry, *prev;
  48
  49         if (sm == NULL)
  50                 return;
  51
  52         entry = sm->pmksa_candidates;
  53         sm->pmksa_candidates = NULL;
  54         while (entry) {
  55                 prev = entry;
  56                 entry = entry->next;
  57                 os_free(prev);
  58         }
  59 }
  60
  61
  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             os_memcmp(sm->preauth_bssid, src_addr, ETH_ALEN) != 0) {
  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 }
  81
  82
  83 static void rsn_preauth_eapol_cb(struct eapol_sm *eapol, int success,
  84                                  void *ctx)
  85 {
  86         struct wpa_sm *sm = ctx;
  87         u8 pmk[PMK_LEN];
  88
  89         if (success) {
  90                 int res, pmk_len;
  91                 pmk_len = PMK_LEN;
  92                 res = eapol_sm_get_key(eapol, pmk, PMK_LEN);
  93                 if (res) {
  94                         /*
  95                          * EAP-LEAP is an exception from other EAP methods: it
  96                          * uses only 16-byte PMK.
  97                          */
  98                         res = eapol_sm_get_key(eapol, pmk, 16);
  99                         pmk_len = 16;
 100                 }
 101                 if (res == 0) {
 102                         wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth",
 103                                         pmk, pmk_len);
 104                         sm->pmk_len = pmk_len;
 105                         pmksa_cache_add(sm->pmksa, pmk, pmk_len,
 106                                         sm->preauth_bssid, sm->own_addr,
 107                                         sm->network_ctx);
 108                 } else {
 109                         wpa_msg(sm->ctx->ctx, MSG_INFO, "RSN: failed to get "
 110                                 "master session key from pre-auth EAPOL state "
 111                                 "machines");
 112                         success = 0;
 113                 }
 114         }
 115
 116         wpa_msg(sm->ctx->ctx, MSG_INFO, "RSN: pre-authentication with " MACSTR
 117                 " %s", MAC2STR(sm->preauth_bssid),
 118                 success ? "completed successfully" : "failed");
 119
 120         rsn_preauth_deinit(sm);
 121         rsn_preauth_candidate_process(sm);
 122 }
 123
 124
 125 static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx)
 126 {
 127         struct wpa_sm *sm = eloop_ctx;
 128
 129         wpa_msg(sm->ctx->ctx, MSG_INFO, "RSN: pre-authentication with " MACSTR
 130                 " timed out", MAC2STR(sm->preauth_bssid));
 131         rsn_preauth_deinit(sm);
 132         rsn_preauth_candidate_process(sm);
 133 }
 134
 135
 136 static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf,
 137                                   size_t len)
 138 {
 139         struct wpa_sm *sm = ctx;
 140         u8 *msg;
 141         size_t msglen;
 142         int res;
 143
 144         /* TODO: could add l2_packet_sendmsg that allows fragments to avoid
 145          * extra copy here */
 146
 147         if (sm->l2_preauth == NULL)
 148                 return -1;
 149
 150         msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL);
 151         if (msg == NULL)
 152                 return -1;
 153
 154         wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen);
 155         res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid,
 156                              ETH_P_RSN_PREAUTH, msg, msglen);
 157         os_free(msg);
 158         return res;
 159 }
 160
 161
 162 /**
 163  * rsn_preauth_init - Start new RSN pre-authentication
 164  * @sm: Pointer to WPA state machine data from wpa_sm_init()
 165  * @dst: Authenticator address (BSSID) with which to preauthenticate
 166  * @eap_conf: Current EAP configuration
 167  * Returns: 0 on success, -1 on another pre-authentication is in progress,
 168  * -2 on layer 2 packet initialization failure, -3 on EAPOL state machine
 169  * initialization failure, -4 on memory allocation failure
 170  *
 171  * This function request an RSN pre-authentication with a given destination
 172  * address. This is usually called for PMKSA candidates found from scan results
 173  * or from driver reports. In addition, ctrl_iface PREAUTH command can trigger
 174  * pre-authentication.
 175  */
 176 int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst,
 177                      struct eap_peer_config *eap_conf)
 178 {
 179         struct eapol_config eapol_conf;
 180         struct eapol_ctx *ctx;
 181
 182         if (sm->preauth_eapol)
 183                 return -1;
 184
 185         wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: starting pre-authentication "
 186                 "with " MACSTR, MAC2STR(dst));
 187
 188         sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr,
 189                                         ETH_P_RSN_PREAUTH,
 190                                         rsn_preauth_receive, sm, 0);
 191         if (sm->l2_preauth == NULL) {
 192                 wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet "
 193                            "processing for pre-authentication");
 194                 return -2;
 195         }
 196
 197         if (sm->bridge_ifname) {
 198                 sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname,
 199                                                    sm->own_addr,
 200                                                    ETH_P_RSN_PREAUTH,
 201                                                    rsn_preauth_receive, sm, 0);
 202                 if (sm->l2_preauth_br == NULL) {
 203                         wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 "
 204                                    "packet processing (bridge) for "
 205                                    "pre-authentication");
 206                         return -2;
 207                 }
 208         }
 209
 210         ctx = os_zalloc(sizeof(*ctx));
 211         if (ctx == NULL) {
 212                 wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context.");
 213                 return -4;
 214         }
 215         ctx->ctx = sm->ctx->ctx;
 216         ctx->msg_ctx = sm->ctx->ctx;
 217         ctx->preauth = 1;
 218         ctx->cb = rsn_preauth_eapol_cb;
 219         ctx->cb_ctx = sm;
 220         ctx->scard_ctx = sm->scard_ctx;
 221         ctx->eapol_send = rsn_preauth_eapol_send;
 222         ctx->eapol_send_ctx = sm;
 223         ctx->set_config_blob = sm->ctx->set_config_blob;
 224         ctx->get_config_blob = sm->ctx->get_config_blob;
 225
 226         sm->preauth_eapol = eapol_sm_init(ctx);
 227         if (sm->preauth_eapol == NULL) {
 228                 os_free(ctx);
 229                 wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL "
 230                            "state machines for pre-authentication");
 231                 return -3;
 232         }
 233         os_memset(&eapol_conf, 0, sizeof(eapol_conf));
 234         eapol_conf.accept_802_1x_keys = 0;
 235         eapol_conf.required_keys = 0;
 236         eapol_conf.fast_reauth = sm->fast_reauth;
 237         eapol_conf.workaround = sm->eap_workaround;
 238         eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf);
 239         /*
 240          * Use a shorter startPeriod with preauthentication since the first
 241          * preauth EAPOL-Start frame may end up being dropped due to race
 242          * condition in the AP between the data receive and key configuration
 243          * after the 4-Way Handshake.
 244          */
 245         eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6);
 246         os_memcpy(sm->preauth_bssid, dst, ETH_ALEN);
 247
 248         eapol_sm_notify_portValid(sm->preauth_eapol, TRUE);
 249         /* 802.1X::portControl = Auto */
 250         eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE);
 251
 252         eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0,
 253                                rsn_preauth_timeout, sm, NULL);
 254
 255         return 0;
 256 }
 257
 258
 259 /**
 260  * rsn_preauth_deinit - Abort RSN pre-authentication
 261  * @sm: Pointer to WPA state machine data from wpa_sm_init()
 262  *
 263  * This function aborts the current RSN pre-authentication (if one is started)
 264  * and frees resources allocated for it.
 265  */
 266 void rsn_preauth_deinit(struct wpa_sm *sm)
 267 {
 268         if (sm == NULL || !sm->preauth_eapol)
 269                 return;
 270
 271         eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL);
 272         eapol_sm_deinit(sm->preauth_eapol);
 273         sm->preauth_eapol = NULL;
 274         os_memset(sm->preauth_bssid, 0, ETH_ALEN);
 275
 276         l2_packet_deinit(sm->l2_preauth);
 277         sm->l2_preauth = NULL;
 278         if (sm->l2_preauth_br) {
 279                 l2_packet_deinit(sm->l2_preauth_br);
 280                 sm->l2_preauth_br = NULL;
 281         }
 282 }
 283
 284
 285 /**
 286  * rsn_preauth_candidate_process - Process PMKSA candidates
 287  * @sm: Pointer to WPA state machine data from wpa_sm_init()
 288  *
 289  * Go through the PMKSA candidates and start pre-authentication if a candidate
 290  * without an existing PMKSA cache entry is found. Processed candidates will be
 291  * removed from the list.
 292  */
 293 void rsn_preauth_candidate_process(struct wpa_sm *sm)
 294 {
 295         struct rsn_pmksa_candidate *candidate;
 296
 297         if (sm->pmksa_candidates == NULL)
 298                 return;
 299
 300         /* TODO: drop priority for old candidate entries */
 301
 302         wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: processing PMKSA candidate "
 303                 "list");
 304         if (sm->preauth_eapol ||
 305             sm->proto != WPA_PROTO_RSN ||
 306             wpa_sm_get_state(sm) != WPA_COMPLETED ||
 307             sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X) {
 308                 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: not in suitable state "
 309                         "for new pre-authentication");
 310                 return; /* invalid state for new pre-auth */
 311         }
 312
 313         while (sm->pmksa_candidates) {
 314                 struct rsn_pmksa_cache_entry *p = NULL;
 315                 candidate = sm->pmksa_candidates;
 316                 p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL);
 317                 if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 &&
 318                     (p == NULL || p->opportunistic)) {
 319                         wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: PMKSA "
 320                                 "candidate " MACSTR
 321                                 " selected for pre-authentication",
 322                                 MAC2STR(candidate->bssid));
 323                         sm->pmksa_candidates = candidate->next;
 324                         rsn_preauth_init(sm, candidate->bssid,
 325                                          sm->eap_conf_ctx);
 326                         os_free(candidate);
 327                         return;
 328                 }
 329                 wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: PMKSA candidate "
 330                         MACSTR " does not need pre-authentication anymore",
 331                         MAC2STR(candidate->bssid));
 332                 /* Some drivers (e.g., NDIS) expect to get notified about the
 333                  * PMKIDs again, so report the existing data now. */
 334                 if (p) {
 335                         wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid);
 336                 }
 337
 338                 sm->pmksa_candidates = candidate->next;
 339                 os_free(candidate);
 340         }
 341         wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: no more pending PMKSA "
 342                 "candidates");
 343 }
 344
 345
 346 /**
 347  * pmksa_candidate_add - Add a new PMKSA candidate
 348  * @sm: Pointer to WPA state machine data from wpa_sm_init()
 349  * @bssid: BSSID (authenticator address) of the candidate
 350  * @prio: Priority (the smaller number, the higher priority)
 351  * @preauth: Whether the candidate AP advertises support for pre-authentication
 352  *
 353  * This function is used to add PMKSA candidates for RSN pre-authentication. It
 354  * is called from scan result processing and from driver events for PMKSA
 355  * candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event().
 356  */
 357 void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid,
 358                          int prio, int preauth)
 359 {
 360         struct rsn_pmksa_candidate *cand, *prev, *pos;
 361
 362         if (sm->network_ctx && sm->proactive_key_caching)
 363                 pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx,
 364                                               bssid);
 365
 366         if (!preauth) {
 367                 wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without "
 368                            "preauth flag");
 369                 return;
 370         }
 371
 372         /* If BSSID already on candidate list, update the priority of the old
 373          * entry. Do not override priority based on normal scan results. */
 374         prev = NULL;
 375         cand = sm->pmksa_candidates;
 376         while (cand) {
 377                 if (os_memcmp(cand->bssid, bssid, ETH_ALEN) == 0) {
 378                         if (prev)
 379                                 prev->next = cand->next;
 380                         else
 381                                 sm->pmksa_candidates = cand->next;
 382                         break;
 383                 }
 384                 prev = cand;
 385                 cand = cand->next;
 386         }
 387
 388         if (cand) {
 389                 if (prio < PMKID_CANDIDATE_PRIO_SCAN)
 390                         cand->priority = prio;
 391         } else {
 392                 cand = os_zalloc(sizeof(*cand));
 393                 if (cand == NULL)
 394                         return;
 395                 os_memcpy(cand->bssid, bssid, ETH_ALEN);
 396                 cand->priority = prio;
 397         }
 398
 399         /* Add candidate to the list; order by increasing priority value. i.e.,
 400          * highest priority (smallest value) first. */
 401         prev = NULL;
 402         pos = sm->pmksa_candidates;
 403         while (pos) {
 404                 if (cand->priority <= pos->priority)
 405                         break;
 406                 prev = pos;
 407                 pos = pos->next;
 408         }
 409         cand->next = pos;
 410         if (prev)
 411                 prev->next = cand;
 412         else
 413                 sm->pmksa_candidates = cand;
 414
 415         wpa_msg(sm->ctx->ctx, MSG_DEBUG, "RSN: added PMKSA cache "
 416                 "candidate " MACSTR " prio %d", MAC2STR(bssid), prio);
 417         rsn_preauth_candidate_process(sm);
 418 }
 419
 420
 421 /* TODO: schedule periodic scans if current AP supports preauth */
 422
 423 /**
 424  * rsn_preauth_scan_results - Process scan results to find PMKSA candidates
 425  * @sm: Pointer to WPA state machine data from wpa_sm_init()
 426  * @results: Scan results
 427  *
 428  * This functions goes through the scan results and adds all suitable APs
 429  * (Authenticators) into PMKSA candidate list.
 430  */
 431 void rsn_preauth_scan_results(struct wpa_sm *sm,
 432                               struct wpa_scan_results *results)
 433 {
 434         struct wpa_scan_res *r;
 435         struct wpa_ie_data ie;
 436         int i;
 437         struct rsn_pmksa_cache_entry *pmksa;
 438
 439         if (sm->ssid_len == 0)
 440                 return;
 441
 442         /*
 443          * TODO: is it ok to free all candidates? What about the entries
 444          * received from EVENT_PMKID_CANDIDATE?
 445          */
 446         pmksa_candidate_free(sm);
 447
 448         for (i = results->num - 1; i >= 0; i--) {
 449                 const u8 *ssid, *rsn;
 450
 451                 r = results->res[i];
 452
 453                 ssid = wpa_scan_get_ie(r, WLAN_EID_SSID);
 454                 if (ssid == NULL || ssid[1] != sm->ssid_len ||
 455                     os_memcmp(ssid + 2, sm->ssid, ssid[1]) != 0)
 456                         continue;
 457
 458                 if (os_memcmp(r->bssid, sm->bssid, ETH_ALEN) == 0)
 459                         continue;
 460
 461                 rsn = wpa_scan_get_ie(r, WLAN_EID_RSN);
 462                 if (rsn == NULL || wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie))
 463                         continue;
 464
 465                 pmksa = pmksa_cache_get(sm->pmksa, r->bssid, NULL);
 466                 if (pmksa &&
 467                     (!pmksa->opportunistic ||
 468                      !(ie.capabilities & WPA_CAPABILITY_PREAUTH)))
 469                         continue;
 470
 471                 /*
 472                  * Give less priority to candidates found from normal
 473                  * scan results.
 474                  */
 475                 pmksa_candidate_add(sm, r->bssid,
 476                                     PMKID_CANDIDATE_PRIO_SCAN,
 477                                     ie.capabilities & WPA_CAPABILITY_PREAUTH);
 478         }
 479 }
 480
 481
 482 #ifdef CONFIG_CTRL_IFACE
 483 /**
 484  * rsn_preauth_get_status - Get pre-authentication status
 485  * @sm: Pointer to WPA state machine data from wpa_sm_init()
 486  * @buf: Buffer for status information
 487  * @buflen: Maximum buffer length
 488  * @verbose: Whether to include verbose status information
 489  * Returns: Number of bytes written to buf.
 490  *
 491  * Query WPA2 pre-authentication for status information. This function fills in
 492  * a text area with current status information. If the buffer (buf) is not
 493  * large enough, status information will be truncated to fit the buffer.
 494  */
 495 int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
 496                            int verbose)
 497 {
 498         char *pos = buf, *end = buf + buflen;
 499         int res, ret;
 500
 501         if (sm->preauth_eapol) {
 502                 ret = os_snprintf(pos, end - pos, "Pre-authentication "
 503                                   "EAPOL state machines:\n");
 504                 if (ret < 0 || ret >= end - pos)
 505                         return pos - buf;
 506                 pos += ret;
 507                 res = eapol_sm_get_status(sm->preauth_eapol,
 508                                           pos, end - pos, verbose);
 509                 if (res >= 0)
 510                         pos += res;
 511         }
 512
 513         return pos - buf;
 514 }
 515 #endif /* CONFIG_CTRL_IFACE */
 516
 517
 518 /**
 519  * rsn_preauth_in_progress - Verify whether pre-authentication is in progress
 520  * @sm: Pointer to WPA state machine data from wpa_sm_init()
 521  */
 522 int rsn_preauth_in_progress(struct wpa_sm *sm)
 523 {
 524         return sm->preauth_eapol != NULL;
 525 }
 526
 527 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */