contrib/hostapd-0.5.8/eap_sake.c

   1 /*
   2  * hostapd / EAP-SAKE (RFC 4763) server
   3  * Copyright (c) 2006, 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 "hostapd.h"
  18 #include "common.h"
  19 #include "eap_i.h"
  20 #include "eap_sake_common.h"
  21
  22
  23 struct eap_sake_data {
  24         enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state;
  25         u8 rand_s[EAP_SAKE_RAND_LEN];
  26         u8 rand_p[EAP_SAKE_RAND_LEN];
  27         struct {
  28                 u8 auth[EAP_SAKE_TEK_AUTH_LEN];
  29                 u8 cipher[EAP_SAKE_TEK_CIPHER_LEN];
  30         } tek;
  31         u8 msk[EAP_MSK_LEN];
  32         u8 emsk[EAP_EMSK_LEN];
  33         u8 session_id;
  34         u8 *peerid;
  35         size_t peerid_len;
  36         u8 *serverid;
  37         size_t serverid_len;
  38 };
  39
  40
  41 static const char * eap_sake_state_txt(int state)
  42 {
  43         switch (state) {
  44         case IDENTITY:
  45                 return "IDENTITY";
  46         case CHALLENGE:
  47                 return "CHALLENGE";
  48         case CONFIRM:
  49                 return "CONFIRM";
  50         case SUCCESS:
  51                 return "SUCCESS";
  52         case FAILURE:
  53                 return "FAILURE";
  54         default:
  55                 return "?";
  56         }
  57 }
  58
  59
  60 static void eap_sake_state(struct eap_sake_data *data, int state)
  61 {
  62         wpa_printf(MSG_DEBUG, "EAP-SAKE: %s -> %s",
  63                    eap_sake_state_txt(data->state),
  64                    eap_sake_state_txt(state));
  65         data->state = state;
  66 }
  67
  68
  69 static void * eap_sake_init(struct eap_sm *sm)
  70 {
  71         struct eap_sake_data *data;
  72
  73         data = wpa_zalloc(sizeof(*data));
  74         if (data == NULL)
  75                 return NULL;
  76         data->state = CHALLENGE;
  77
  78         if (hostapd_get_rand(&data->session_id, 1)) {
  79                 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
  80                 os_free(data);
  81                 return NULL;
  82         }
  83         wpa_printf(MSG_DEBUG, "EAP-SAKE: Initialized Session ID %d",
  84                    data->session_id);
  85
  86         /* TODO: add support for configuring SERVERID */
  87         data->serverid = (u8 *) strdup("hostapd");
  88         if (data->serverid)
  89                 data->serverid_len = strlen((char *) data->serverid);
  90
  91         return data;
  92 }
  93
  94
  95 static void eap_sake_reset(struct eap_sm *sm, void *priv)
  96 {
  97         struct eap_sake_data *data = priv;
  98         os_free(data->serverid);
  99         os_free(data->peerid);
 100         os_free(data);
 101 }
 102
 103
 104 static u8 * eap_sake_build_msg(struct eap_sake_data *data, u8 **payload,
 105                                int id, size_t *length, u8 subtype)
 106 {
 107         struct eap_sake_hdr *req;
 108         u8 *msg;
 109
 110         *length += sizeof(struct eap_sake_hdr);
 111
 112         msg = wpa_zalloc(*length);
 113         if (msg == NULL) {
 114                 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to allocate memory "
 115                            "request");
 116                 return NULL;
 117         }
 118
 119         req = (struct eap_sake_hdr *) msg;
 120         req->code = EAP_CODE_REQUEST;
 121         req->identifier = id;
 122         req->length = htons((u16) *length);
 123         req->type = EAP_TYPE_SAKE;
 124         req->version = EAP_SAKE_VERSION;
 125         req->session_id = data->session_id;
 126         req->subtype = subtype;
 127         *payload = (u8 *) (req + 1);
 128
 129         return msg;
 130 }
 131
 132
 133 static u8 * eap_sake_build_identity(struct eap_sm *sm,
 134                                     struct eap_sake_data *data,
 135                                     int id, size_t *reqDataLen)
 136 {
 137         u8 *msg, *pos;
 138
 139         wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Identity");
 140
 141         *reqDataLen = 4;
 142         if (data->serverid)
 143                 *reqDataLen += 2 + data->serverid_len;
 144         msg = eap_sake_build_msg(data, &pos, id, reqDataLen,
 145                                  EAP_SAKE_SUBTYPE_IDENTITY);
 146         if (msg == NULL) {
 147                 data->state = FAILURE;
 148                 return NULL;
 149         }
 150
 151         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PERM_ID_REQ");
 152         *pos++ = EAP_SAKE_AT_PERM_ID_REQ;
 153         *pos++ = 4;
 154         *pos++ = 0;
 155         *pos++ = 0;
 156
 157         if (data->serverid) {
 158                 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID");
 159                 *pos++ = EAP_SAKE_AT_SERVERID;
 160                 *pos++ = 2 + data->serverid_len;
 161                 os_memcpy(pos, data->serverid, data->serverid_len);
 162         }
 163
 164         return msg;
 165 }
 166
 167
 168 static u8 * eap_sake_build_challenge(struct eap_sm *sm,
 169                                      struct eap_sake_data *data,
 170                                      int id, size_t *reqDataLen)
 171 {
 172         u8 *msg, *pos;
 173
 174         wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge");
 175
 176         if (hostapd_get_rand(data->rand_s, EAP_SAKE_RAND_LEN)) {
 177                 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
 178                 data->state = FAILURE;
 179                 return NULL;
 180         }
 181         wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)",
 182                     data->rand_s, EAP_SAKE_RAND_LEN);
 183
 184         *reqDataLen = 2 + EAP_SAKE_RAND_LEN;
 185         if (data->serverid)
 186                 *reqDataLen += 2 + data->serverid_len;
 187         msg = eap_sake_build_msg(data, &pos, id, reqDataLen,
 188                                  EAP_SAKE_SUBTYPE_CHALLENGE);
 189         if (msg == NULL) {
 190                 data->state = FAILURE;
 191                 return NULL;
 192         }
 193
 194         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_S");
 195         *pos++ = EAP_SAKE_AT_RAND_S;
 196         *pos++ = 2 + EAP_SAKE_RAND_LEN;
 197         os_memcpy(pos, data->rand_s, EAP_SAKE_RAND_LEN);
 198         pos += EAP_SAKE_RAND_LEN;
 199
 200         if (data->serverid) {
 201                 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID");
 202                 *pos++ = EAP_SAKE_AT_SERVERID;
 203                 *pos++ = 2 + data->serverid_len;
 204                 os_memcpy(pos, data->serverid, data->serverid_len);
 205         }
 206
 207         return msg;
 208 }
 209
 210
 211 static u8 * eap_sake_build_confirm(struct eap_sm *sm,
 212                                    struct eap_sake_data *data,
 213                                    int id, size_t *reqDataLen)
 214 {
 215         u8 *msg, *pos;
 216
 217         wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Confirm");
 218
 219         *reqDataLen = 2 + EAP_SAKE_MIC_LEN;
 220         msg = eap_sake_build_msg(data, &pos, id, reqDataLen,
 221                                  EAP_SAKE_SUBTYPE_CONFIRM);
 222         if (msg == NULL) {
 223                 data->state = FAILURE;
 224                 return NULL;
 225         }
 226
 227         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_S");
 228         *pos++ = EAP_SAKE_AT_MIC_S;
 229         *pos++ = 2 + EAP_SAKE_MIC_LEN;
 230         if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 231                                  data->serverid, data->serverid_len,
 232                                  data->peerid, data->peerid_len, 0,
 233                                  msg, *reqDataLen, pos, pos)) {
 234                 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
 235                 data->state = FAILURE;
 236                 os_free(msg);
 237                 return NULL;
 238         }
 239
 240         return msg;
 241 }
 242
 243
 244 static u8 * eap_sake_buildReq(struct eap_sm *sm, void *priv, int id,
 245                               size_t *reqDataLen)
 246 {
 247         struct eap_sake_data *data = priv;
 248
 249         switch (data->state) {
 250         case IDENTITY:
 251                 return eap_sake_build_identity(sm, data, id, reqDataLen);
 252         case CHALLENGE:
 253                 return eap_sake_build_challenge(sm, data, id, reqDataLen);
 254         case CONFIRM:
 255                 return eap_sake_build_confirm(sm, data, id, reqDataLen);
 256         default:
 257                 wpa_printf(MSG_DEBUG, "EAP-SAKE: Unknown state %d in buildReq",
 258                            data->state);
 259                 break;
 260         }
 261         return NULL;
 262 }
 263
 264
 265 static Boolean eap_sake_check(struct eap_sm *sm, void *priv,
 266                               u8 *respData, size_t respDataLen)
 267 {
 268         struct eap_sake_data *data = priv;
 269         struct eap_sake_hdr *resp;
 270         size_t len;
 271         u8 version, session_id, subtype;
 272
 273         resp = (struct eap_sake_hdr *) respData;
 274         if (respDataLen < sizeof(*resp) ||
 275             resp->type != EAP_TYPE_SAKE ||
 276             (len = ntohs(resp->length)) > respDataLen ||
 277             len < sizeof(*resp)) {
 278                 wpa_printf(MSG_INFO, "EAP-SAKE: Invalid frame");
 279                 return TRUE;
 280         }
 281         version = resp->version;
 282         session_id = resp->session_id;
 283         subtype = resp->subtype;
 284
 285         if (version != EAP_SAKE_VERSION) {
 286                 wpa_printf(MSG_INFO, "EAP-SAKE: Unknown version %d", version);
 287                 return TRUE;
 288         }
 289
 290         if (session_id != data->session_id) {
 291                 wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
 292                            session_id, data->session_id);
 293                 return TRUE;
 294         }
 295
 296         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype=%d", subtype);
 297
 298         if (data->state == IDENTITY && subtype == EAP_SAKE_SUBTYPE_IDENTITY)
 299                 return FALSE;
 300
 301         if (data->state == CHALLENGE && subtype == EAP_SAKE_SUBTYPE_CHALLENGE)
 302                 return FALSE;
 303
 304         if (data->state == CONFIRM && subtype == EAP_SAKE_SUBTYPE_CONFIRM)
 305                 return FALSE;
 306
 307         if (subtype == EAP_SAKE_SUBTYPE_AUTH_REJECT)
 308                 return FALSE;
 309
 310         wpa_printf(MSG_INFO, "EAP-SAKE: Unexpected subtype=%d in state=%d",
 311                    subtype, data->state);
 312
 313         return TRUE;
 314 }
 315
 316
 317 static void eap_sake_process_identity(struct eap_sm *sm,
 318                                       struct eap_sake_data *data,
 319                                       u8 *respData, size_t respDataLen,
 320                                       u8 *payload, size_t payloadlen)
 321 {
 322         if (data->state != IDENTITY)
 323                 return;
 324
 325         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Identity");
 326         /* TODO: update identity and select new user data */
 327         eap_sake_state(data, CHALLENGE);
 328 }
 329
 330
 331 static void eap_sake_process_challenge(struct eap_sm *sm,
 332                                        struct eap_sake_data *data,
 333                                        u8 *respData, size_t respDataLen,
 334                                        u8 *payload, size_t payloadlen)
 335 {
 336         struct eap_sake_parse_attr attr;
 337         u8 mic_p[EAP_SAKE_MIC_LEN];
 338
 339         if (data->state != CHALLENGE)
 340                 return;
 341
 342         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Challenge");
 343
 344         if (eap_sake_parse_attributes(payload, payloadlen, &attr))
 345                 return;
 346
 347         if (!attr.rand_p || !attr.mic_p) {
 348                 wpa_printf(MSG_INFO, "EAP-SAKE: Response/Challenge did not "
 349                            "include AT_RAND_P or AT_MIC_P");
 350                 return;
 351         }
 352
 353         os_memcpy(data->rand_p, attr.rand_p, EAP_SAKE_RAND_LEN);
 354
 355         os_free(data->peerid);
 356         data->peerid = NULL;
 357         data->peerid_len = 0;
 358         if (attr.peerid) {
 359                 data->peerid = os_malloc(attr.peerid_len);
 360                 if (data->peerid == NULL)
 361                         return;
 362                 os_memcpy(data->peerid, attr.peerid, attr.peerid_len);
 363                 data->peerid_len = attr.peerid_len;
 364         }
 365
 366         if (sm->user == NULL || sm->user->password == NULL ||
 367             sm->user->password_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) {
 368                 wpa_printf(MSG_INFO, "EAP-SAKE: Plaintext password with "
 369                            "%d-byte key not configured",
 370                            2 * EAP_SAKE_ROOT_SECRET_LEN);
 371                 data->state = FAILURE;
 372                 return;
 373         }
 374         eap_sake_derive_keys(sm->user->password,
 375                              sm->user->password + EAP_SAKE_ROOT_SECRET_LEN,
 376                              data->rand_s, data->rand_p,
 377                              (u8 *) &data->tek, data->msk, data->emsk);
 378
 379         eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 380                              data->serverid, data->serverid_len,
 381                              data->peerid, data->peerid_len, 1,
 382                              respData, respDataLen, attr.mic_p, mic_p);
 383         if (os_memcmp(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
 384                 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
 385                 eap_sake_state(data, FAILURE);
 386                 return;
 387         }
 388
 389         eap_sake_state(data, CONFIRM);
 390 }
 391
 392
 393 static void eap_sake_process_confirm(struct eap_sm *sm,
 394                                      struct eap_sake_data *data,
 395                                      u8 *respData, size_t respDataLen,
 396                                      u8 *payload, size_t payloadlen)
 397 {
 398         struct eap_sake_parse_attr attr;
 399         u8 mic_p[EAP_SAKE_MIC_LEN];
 400
 401         if (data->state != CONFIRM)
 402                 return;
 403
 404         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Confirm");
 405
 406         if (eap_sake_parse_attributes(payload, payloadlen, &attr))
 407                 return;
 408
 409         if (!attr.mic_p) {
 410                 wpa_printf(MSG_INFO, "EAP-SAKE: Response/Confirm did not "
 411                            "include AT_MIC_P");
 412                 return;
 413         }
 414
 415         eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 416                              data->serverid, data->serverid_len,
 417                              data->peerid, data->peerid_len, 1,
 418                              respData, respDataLen, attr.mic_p, mic_p);
 419         if (os_memcmp(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
 420                 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
 421                 eap_sake_state(data, FAILURE);
 422         } else
 423                 eap_sake_state(data, SUCCESS);
 424 }
 425
 426
 427 static void eap_sake_process_auth_reject(struct eap_sm *sm,
 428                                          struct eap_sake_data *data,
 429                                          u8 *respData, size_t respDataLen,
 430                                          u8 *payload, size_t payloadlen)
 431 {
 432         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Auth-Reject");
 433         eap_sake_state(data, FAILURE);
 434 }
 435
 436
 437 static void eap_sake_process(struct eap_sm *sm, void *priv,
 438                              u8 *respData, size_t respDataLen)
 439 {
 440         struct eap_sake_data *data = priv;
 441         struct eap_sake_hdr *resp;
 442         u8 subtype, *pos, *end;
 443
 444         resp = (struct eap_sake_hdr *) respData;
 445         subtype = resp->subtype;
 446         pos = (u8 *) (resp + 1);
 447         end = respData + ntohs(resp->length);
 448
 449         wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
 450                     pos, end - pos);
 451
 452         switch (subtype) {
 453         case EAP_SAKE_SUBTYPE_IDENTITY:
 454                 eap_sake_process_identity(sm, data, respData, respDataLen, pos,
 455                                           end - pos);
 456                 break;
 457         case EAP_SAKE_SUBTYPE_CHALLENGE:
 458                 eap_sake_process_challenge(sm, data, respData, respDataLen,
 459                                            pos, end - pos);
 460                 break;
 461         case EAP_SAKE_SUBTYPE_CONFIRM:
 462                 eap_sake_process_confirm(sm, data, respData, respDataLen, pos,
 463                                          end - pos);
 464                 break;
 465         case EAP_SAKE_SUBTYPE_AUTH_REJECT:
 466                 eap_sake_process_auth_reject(sm, data, respData, respDataLen,
 467                                              pos, end - pos);
 468                 break;
 469         }
 470 }
 471
 472
 473 static Boolean eap_sake_isDone(struct eap_sm *sm, void *priv)
 474 {
 475         struct eap_sake_data *data = priv;
 476         return data->state == SUCCESS || data->state == FAILURE;
 477 }
 478
 479
 480 static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len)
 481 {
 482         struct eap_sake_data *data = priv;
 483         u8 *key;
 484
 485         if (data->state != SUCCESS)
 486                 return NULL;
 487
 488         key = os_malloc(EAP_MSK_LEN);
 489         if (key == NULL)
 490                 return NULL;
 491         os_memcpy(key, data->msk, EAP_MSK_LEN);
 492         *len = EAP_MSK_LEN;
 493
 494         return key;
 495 }
 496
 497
 498 static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 499 {
 500         struct eap_sake_data *data = priv;
 501         u8 *key;
 502
 503         if (data->state != SUCCESS)
 504                 return NULL;
 505
 506         key = os_malloc(EAP_EMSK_LEN);
 507         if (key == NULL)
 508                 return NULL;
 509         os_memcpy(key, data->emsk, EAP_EMSK_LEN);
 510         *len = EAP_EMSK_LEN;
 511
 512         return key;
 513 }
 514
 515
 516 static Boolean eap_sake_isSuccess(struct eap_sm *sm, void *priv)
 517 {
 518         struct eap_sake_data *data = priv;
 519         return data->state == SUCCESS;
 520 }
 521
 522
 523 int eap_server_sake_register(void)
 524 {
 525         struct eap_method *eap;
 526         int ret;
 527
 528         eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
 529                                       EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE");
 530         if (eap == NULL)
 531                 return -1;
 532
 533         eap->init = eap_sake_init;
 534         eap->reset = eap_sake_reset;
 535         eap->buildReq = eap_sake_buildReq;
 536         eap->check = eap_sake_check;
 537         eap->process = eap_sake_process;
 538         eap->isDone = eap_sake_isDone;
 539         eap->getKey = eap_sake_getKey;
 540         eap->isSuccess = eap_sake_isSuccess;
 541         eap->get_emsk = eap_sake_get_emsk;
 542
 543         ret = eap_server_method_register(eap);
 544         if (ret)
 545                 eap_server_method_free(eap);
 546         return ret;
 547 }