www.project-moonshot.org Git - mech_eap.orig/blob - libeap/src/rsn_supp/preauth.c

   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
  33 struct 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  */
  44 void 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
  59 static 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
  80 static 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
 123 static 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
 134 static 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  */
 174 int 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  */
 264 void 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  */
 291 void 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  */
 356 void 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  */
 424 int 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  */
 446 void 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  */
 486 int 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  */
 513 int 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 */