contrib/wpa_supplicant-0.5.8/eap_sake.c

   1 /*
   2  * EAP peer method: EAP-SAKE (RFC 4763)
   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 "common.h"
  18 #include "eap_i.h"
  19 #include "config_ssid.h"
  20 #include "eap_sake_common.h"
  21
  22 struct eap_sake_data {
  23         enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state;
  24         u8 root_secret_a[EAP_SAKE_ROOT_SECRET_LEN];
  25         u8 root_secret_b[EAP_SAKE_ROOT_SECRET_LEN];
  26         u8 rand_s[EAP_SAKE_RAND_LEN];
  27         u8 rand_p[EAP_SAKE_RAND_LEN];
  28         struct {
  29                 u8 auth[EAP_SAKE_TEK_AUTH_LEN];
  30                 u8 cipher[EAP_SAKE_TEK_CIPHER_LEN];
  31         } tek;
  32         u8 msk[EAP_MSK_LEN];
  33         u8 emsk[EAP_EMSK_LEN];
  34         u8 session_id;
  35         int session_id_set;
  36         u8 *peerid;
  37         size_t peerid_len;
  38         u8 *serverid;
  39         size_t serverid_len;
  40 };
  41
  42
  43 static const char * eap_sake_state_txt(int state)
  44 {
  45         switch (state) {
  46         case IDENTITY:
  47                 return "IDENTITY";
  48         case CHALLENGE:
  49                 return "CHALLENGE";
  50         case CONFIRM:
  51                 return "CONFIRM";
  52         case SUCCESS:
  53                 return "SUCCESS";
  54         case FAILURE:
  55                 return "FAILURE";
  56         default:
  57                 return "?";
  58         }
  59 }
  60
  61
  62 static void eap_sake_state(struct eap_sake_data *data, int state)
  63 {
  64         wpa_printf(MSG_DEBUG, "EAP-SAKE: %s -> %s",
  65                    eap_sake_state_txt(data->state),
  66                    eap_sake_state_txt(state));
  67         data->state = state;
  68 }
  69
  70
  71 static void eap_sake_deinit(struct eap_sm *sm, void *priv);
  72
  73
  74 static void * eap_sake_init(struct eap_sm *sm)
  75 {
  76         struct wpa_ssid *config = eap_get_config(sm);
  77         struct eap_sake_data *data;
  78
  79         if (config == NULL) {
  80                 wpa_printf(MSG_INFO, "EAP-SAKE: No configuration found");
  81                 return NULL;
  82         }
  83
  84         if (!config->eappsk ||
  85             config->eappsk_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) {
  86                 wpa_printf(MSG_INFO, "EAP-SAKE: No key (eappsk) of correct "
  87                            "length configured");
  88                 return NULL;
  89         }
  90
  91         data = os_zalloc(sizeof(*data));
  92         if (data == NULL)
  93                 return NULL;
  94         data->state = IDENTITY;
  95
  96         if (config->nai) {
  97                 data->peerid = os_malloc(config->nai_len);
  98                 if (data->peerid == NULL) {
  99                         eap_sake_deinit(sm, data);
 100                         return NULL;
 101                 }
 102                 os_memcpy(data->peerid, config->nai, config->nai_len);
 103                 data->peerid_len = config->nai_len;
 104         }
 105
 106         os_memcpy(data->root_secret_a, config->eappsk,
 107                   EAP_SAKE_ROOT_SECRET_LEN);
 108         os_memcpy(data->root_secret_b,
 109                   config->eappsk + EAP_SAKE_ROOT_SECRET_LEN,
 110                   EAP_SAKE_ROOT_SECRET_LEN);
 111
 112         return data;
 113 }
 114
 115
 116 static void eap_sake_deinit(struct eap_sm *sm, void *priv)
 117 {
 118         struct eap_sake_data *data = priv;
 119         os_free(data->serverid);
 120         os_free(data->peerid);
 121         os_free(data);
 122 }
 123
 124
 125 static u8 * eap_sake_build_msg(struct eap_sake_data *data, u8 **payload,
 126                                int id, size_t *length, u8 subtype)
 127 {
 128         struct eap_sake_hdr *req;
 129         u8 *msg;
 130
 131         *length += sizeof(struct eap_sake_hdr);
 132
 133         msg = os_zalloc(*length);
 134         if (msg == NULL) {
 135                 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to allocate memory "
 136                            "request");
 137                 return NULL;
 138         }
 139
 140         req = (struct eap_sake_hdr *) msg;
 141         req->code = EAP_CODE_RESPONSE;
 142         req->identifier = id;
 143         req->length = htons((u16) *length);
 144         req->type = EAP_TYPE_SAKE;
 145         req->version = EAP_SAKE_VERSION;
 146         req->session_id = data->session_id;
 147         req->subtype = subtype;
 148         *payload = (u8 *) (req + 1);
 149
 150         return msg;
 151 }
 152
 153
 154 static u8 * eap_sake_process_identity(struct eap_sm *sm,
 155                                       struct eap_sake_data *data,
 156                                       struct eap_method_ret *ret,
 157                                       const u8 *reqData, size_t reqDataLen,
 158                                       const u8 *payload, size_t payload_len,
 159                                       size_t *respDataLen)
 160 {
 161         struct eap_sake_parse_attr attr;
 162         u8 *resp, *rpos;
 163         const struct eap_hdr *hdr = (const struct eap_hdr *) reqData;
 164
 165         if (data->state != IDENTITY) {
 166                 ret->ignore = TRUE;
 167                 return NULL;
 168         }
 169
 170         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Identity");
 171
 172         if (eap_sake_parse_attributes(payload, payload_len, &attr))
 173                 return NULL;
 174
 175         if (!attr.perm_id_req && !attr.any_id_req) {
 176                 wpa_printf(MSG_INFO, "EAP-SAKE: No AT_PERM_ID_REQ or "
 177                            "AT_ANY_ID_REQ in Request/Identity");
 178                 return NULL;
 179         }
 180
 181         wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Identity");
 182
 183         *respDataLen = 2 + data->peerid_len;
 184         resp = eap_sake_build_msg(data, &rpos, hdr->identifier, respDataLen,
 185                                   EAP_SAKE_SUBTYPE_IDENTITY);
 186         if (resp == NULL)
 187                 return NULL;
 188
 189         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID");
 190         *rpos++ = EAP_SAKE_AT_PEERID;
 191         *rpos++ = 2 + data->peerid_len;
 192         if (data->peerid)
 193                 os_memcpy(rpos, data->peerid, data->peerid_len);
 194
 195         eap_sake_state(data, CHALLENGE);
 196
 197         return resp;
 198 }
 199
 200
 201 static u8 * eap_sake_process_challenge(struct eap_sm *sm,
 202                                        struct eap_sake_data *data,
 203                                        struct eap_method_ret *ret,
 204                                        const u8 *reqData, size_t reqDataLen,
 205                                        const u8 *payload, size_t payload_len,
 206                                        size_t *respDataLen)
 207 {
 208         struct eap_sake_parse_attr attr;
 209         u8 *resp, *rpos;
 210         const struct eap_hdr *hdr = (const struct eap_hdr *) reqData;
 211
 212         if (data->state != IDENTITY && data->state != CHALLENGE) {
 213                 wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge received "
 214                            "in unexpected state (%d)", data->state);
 215                 ret->ignore = TRUE;
 216                 return NULL;
 217         }
 218         if (data->state == IDENTITY)
 219                 eap_sake_state(data, CHALLENGE);
 220
 221         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Challenge");
 222
 223         if (eap_sake_parse_attributes(payload, payload_len, &attr))
 224                 return NULL;
 225
 226         if (!attr.rand_s) {
 227                 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Challenge did not "
 228                            "include AT_RAND_S");
 229                 return NULL;
 230         }
 231
 232         os_memcpy(data->rand_s, attr.rand_s, EAP_SAKE_RAND_LEN);
 233         wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)",
 234                     data->rand_s, EAP_SAKE_RAND_LEN);
 235
 236         if (hostapd_get_rand(data->rand_p, EAP_SAKE_RAND_LEN)) {
 237                 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
 238                 return NULL;
 239         }
 240         wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_P (peer rand)",
 241                     data->rand_p, EAP_SAKE_RAND_LEN);
 242
 243         os_free(data->serverid);
 244         data->serverid = NULL;
 245         data->serverid_len = 0;
 246         if (attr.serverid) {
 247                 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-SAKE: SERVERID",
 248                                   attr.serverid, attr.serverid_len);
 249                 data->serverid = os_malloc(attr.serverid_len);
 250                 if (data->serverid == NULL)
 251                         return NULL;
 252                 os_memcpy(data->serverid, attr.serverid, attr.serverid_len);
 253                 data->serverid_len = attr.serverid_len;
 254         }
 255
 256         eap_sake_derive_keys(data->root_secret_a, data->root_secret_b,
 257                              data->rand_s, data->rand_p,
 258                              (u8 *) &data->tek, data->msk, data->emsk);
 259
 260         wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Challenge");
 261
 262         *respDataLen = 2 + EAP_SAKE_RAND_LEN + 2 + EAP_SAKE_MIC_LEN;
 263         if (data->peerid)
 264                 *respDataLen += 2 + data->peerid_len;
 265         resp = eap_sake_build_msg(data, &rpos, hdr->identifier, respDataLen,
 266                                   EAP_SAKE_SUBTYPE_CHALLENGE);
 267         if (resp == NULL)
 268                 return NULL;
 269
 270         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_P");
 271         *rpos++ = EAP_SAKE_AT_RAND_P;
 272         *rpos++ = 2 + EAP_SAKE_RAND_LEN;
 273         os_memcpy(rpos, data->rand_p, EAP_SAKE_RAND_LEN);
 274         rpos += EAP_SAKE_RAND_LEN;
 275
 276         if (data->peerid) {
 277                 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID");
 278                 *rpos++ = EAP_SAKE_AT_PEERID;
 279                 *rpos++ = 2 + data->peerid_len;
 280                 os_memcpy(rpos, data->peerid, data->peerid_len);
 281                 rpos += data->peerid_len;
 282         }
 283
 284         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
 285         *rpos++ = EAP_SAKE_AT_MIC_P;
 286         *rpos++ = 2 + EAP_SAKE_MIC_LEN;
 287         if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 288                                  data->serverid, data->serverid_len,
 289                                  data->peerid, data->peerid_len, 1,
 290                                  resp, *respDataLen, rpos, rpos)) {
 291                 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
 292                 os_free(resp);
 293                 return NULL;
 294         }
 295
 296         eap_sake_state(data, CONFIRM);
 297
 298         return resp;
 299 }
 300
 301
 302 static u8 * eap_sake_process_confirm(struct eap_sm *sm,
 303                                      struct eap_sake_data *data,
 304                                      struct eap_method_ret *ret,
 305                                      const u8 *reqData, size_t reqDataLen,
 306                                      const u8 *payload, size_t payload_len,
 307                                      size_t *respDataLen)
 308 {
 309         struct eap_sake_parse_attr attr;
 310         u8 mic_s[EAP_SAKE_MIC_LEN];
 311         u8 *resp, *rpos;
 312         const struct eap_hdr *hdr = (const struct eap_hdr *) reqData;
 313
 314         if (data->state != CONFIRM) {
 315                 ret->ignore = TRUE;
 316                 return NULL;
 317         }
 318
 319         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Confirm");
 320
 321         if (eap_sake_parse_attributes(payload, payload_len, &attr))
 322                 return NULL;
 323
 324         if (!attr.mic_s) {
 325                 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Confirm did not "
 326                            "include AT_MIC_S");
 327                 return NULL;
 328         }
 329
 330         eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 331                              data->serverid, data->serverid_len,
 332                              data->peerid, data->peerid_len, 0,
 333                              reqData, reqDataLen, attr.mic_s, mic_s);
 334         if (os_memcmp(attr.mic_s, mic_s, EAP_SAKE_MIC_LEN) != 0) {
 335                 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_S");
 336                 eap_sake_state(data, FAILURE);
 337                 ret->methodState = METHOD_DONE;
 338                 ret->decision = DECISION_FAIL;
 339                 ret->allowNotifications = FALSE;
 340                 *respDataLen = 0;
 341                 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending "
 342                            "Response/Auth-Reject");
 343                 return eap_sake_build_msg(data, &rpos, hdr->identifier,
 344                                           respDataLen,
 345                                           EAP_SAKE_SUBTYPE_AUTH_REJECT);
 346         }
 347
 348         wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Confirm");
 349
 350         *respDataLen = 2 + EAP_SAKE_MIC_LEN;
 351         resp = eap_sake_build_msg(data, &rpos, hdr->identifier, respDataLen,
 352                                   EAP_SAKE_SUBTYPE_CONFIRM);
 353         if (resp == NULL)
 354                 return NULL;
 355
 356         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
 357         *rpos++ = EAP_SAKE_AT_MIC_P;
 358         *rpos++ = 2 + EAP_SAKE_MIC_LEN;
 359         if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 360                                  data->serverid, data->serverid_len,
 361                                  data->peerid, data->peerid_len, 1,
 362                                  resp, *respDataLen, rpos, rpos)) {
 363                 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
 364                 os_free(resp);
 365                 return NULL;
 366         }
 367
 368         eap_sake_state(data, SUCCESS);
 369         ret->methodState = METHOD_DONE;
 370         ret->decision = DECISION_UNCOND_SUCC;
 371         ret->allowNotifications = FALSE;
 372
 373         return resp;
 374 }
 375
 376
 377 static u8 * eap_sake_process(struct eap_sm *sm, void *priv,
 378                             struct eap_method_ret *ret,
 379                             const u8 *reqData, size_t reqDataLen,
 380                             size_t *respDataLen)
 381 {
 382         struct eap_sake_data *data = priv;
 383         const struct eap_sake_hdr *req;
 384         u8 *resp;
 385         const u8 *pos, *end;
 386         size_t len;
 387         u8 subtype, session_id;
 388
 389         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE,
 390                                reqData, reqDataLen, &len);
 391         if (pos == NULL || len < 3) {
 392                 ret->ignore = TRUE;
 393                 return NULL;
 394         }
 395
 396         req = (const struct eap_sake_hdr *) reqData;
 397         subtype = req->subtype;
 398         session_id = req->session_id;
 399         pos = (const u8 *) (req + 1);
 400         end = reqData + be_to_host16(req->length);
 401
 402         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype %d "
 403                    "session_id %d", subtype, session_id);
 404         wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
 405                     pos, end - pos);
 406
 407         if (data->session_id_set && data->session_id != session_id) {
 408                 wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
 409                            session_id, data->session_id);
 410                 ret->ignore = TRUE;
 411                 return NULL;
 412         }
 413         data->session_id = session_id;
 414         data->session_id_set = 1;
 415
 416         ret->ignore = FALSE;
 417         ret->methodState = METHOD_MAY_CONT;
 418         ret->decision = DECISION_FAIL;
 419         ret->allowNotifications = TRUE;
 420
 421         switch (subtype) {
 422         case EAP_SAKE_SUBTYPE_IDENTITY:
 423                 resp = eap_sake_process_identity(sm, data, ret, reqData,
 424                                                  reqDataLen, pos, end - pos,
 425                                                  respDataLen);
 426                 break;
 427         case EAP_SAKE_SUBTYPE_CHALLENGE:
 428                 resp = eap_sake_process_challenge(sm, data, ret, reqData,
 429                                                   reqDataLen, pos, end - pos,
 430                                                   respDataLen);
 431                 break;
 432         case EAP_SAKE_SUBTYPE_CONFIRM:
 433                 resp = eap_sake_process_confirm(sm, data, ret, reqData,
 434                                                 reqDataLen, pos, end - pos,
 435                                                 respDataLen);
 436                 break;
 437         default:
 438                 wpa_printf(MSG_DEBUG, "EAP-SAKE: Ignoring message with "
 439                            "unknown subtype %d", subtype);
 440                 ret->ignore = TRUE;
 441                 return NULL;
 442         }
 443
 444         if (ret->methodState == METHOD_DONE)
 445                 ret->allowNotifications = FALSE;
 446
 447         return resp;
 448 }
 449
 450
 451 static Boolean eap_sake_isKeyAvailable(struct eap_sm *sm, void *priv)
 452 {
 453         struct eap_sake_data *data = priv;
 454         return data->state == SUCCESS;
 455 }
 456
 457
 458 static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len)
 459 {
 460         struct eap_sake_data *data = priv;
 461         u8 *key;
 462
 463         if (data->state != SUCCESS)
 464                 return NULL;
 465
 466         key = os_malloc(EAP_MSK_LEN);
 467         if (key == NULL)
 468                 return NULL;
 469         os_memcpy(key, data->msk, EAP_MSK_LEN);
 470         *len = EAP_MSK_LEN;
 471
 472         return key;
 473 }
 474
 475
 476 static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 477 {
 478         struct eap_sake_data *data = priv;
 479         u8 *key;
 480
 481         if (data->state != SUCCESS)
 482                 return NULL;
 483
 484         key = os_malloc(EAP_EMSK_LEN);
 485         if (key == NULL)
 486                 return NULL;
 487         os_memcpy(key, data->emsk, EAP_EMSK_LEN);
 488         *len = EAP_EMSK_LEN;
 489
 490         return key;
 491 }
 492
 493
 494 int eap_peer_sake_register(void)
 495 {
 496         struct eap_method *eap;
 497         int ret;
 498
 499         eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
 500                                     EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE");
 501         if (eap == NULL)
 502                 return -1;
 503
 504         eap->init = eap_sake_init;
 505         eap->deinit = eap_sake_deinit;
 506         eap->process = eap_sake_process;
 507         eap->isKeyAvailable = eap_sake_isKeyAvailable;
 508         eap->getKey = eap_sake_getKey;
 509         eap->get_emsk = eap_sake_get_emsk;
 510
 511         ret = eap_peer_method_register(eap);
 512         if (ret)
 513                 eap_peer_method_free(eap);
 514         return ret;
 515 }