src/eap_server/eap_server_sake.c

   1 /*
   2  * hostapd / EAP-SAKE (RFC 4763) server
   3  * Copyright (c) 2006-2007, Jouni Malinen <j@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 "crypto/random.h"
  13 #include "eap_server/eap_i.h"
  14 #include "eap_common/eap_sake_common.h"
  15
  16
  17 struct eap_sake_data {
  18         enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state;
  19         u8 rand_s[EAP_SAKE_RAND_LEN];
  20         u8 rand_p[EAP_SAKE_RAND_LEN];
  21         struct {
  22                 u8 auth[EAP_SAKE_TEK_AUTH_LEN];
  23                 u8 cipher[EAP_SAKE_TEK_CIPHER_LEN];
  24         } tek;
  25         u8 msk[EAP_MSK_LEN];
  26         u8 emsk[EAP_EMSK_LEN];
  27         u8 session_id;
  28         u8 *peerid;
  29         size_t peerid_len;
  30 };
  31
  32
  33 static const char * eap_sake_state_txt(int state)
  34 {
  35         switch (state) {
  36         case IDENTITY:
  37                 return "IDENTITY";
  38         case CHALLENGE:
  39                 return "CHALLENGE";
  40         case CONFIRM:
  41                 return "CONFIRM";
  42         case SUCCESS:
  43                 return "SUCCESS";
  44         case FAILURE:
  45                 return "FAILURE";
  46         default:
  47                 return "?";
  48         }
  49 }
  50
  51
  52 static void eap_sake_state(struct eap_sake_data *data, int state)
  53 {
  54         wpa_printf(MSG_DEBUG, "EAP-SAKE: %s -> %s",
  55                    eap_sake_state_txt(data->state),
  56                    eap_sake_state_txt(state));
  57         data->state = state;
  58 }
  59
  60
  61 static void * eap_sake_init(struct eap_sm *sm)
  62 {
  63         struct eap_sake_data *data;
  64
  65         data = os_zalloc(sizeof(*data));
  66         if (data == NULL)
  67                 return NULL;
  68         data->state = CHALLENGE;
  69
  70         if (os_get_random(&data->session_id, 1)) {
  71                 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
  72                 os_free(data);
  73                 return NULL;
  74         }
  75         wpa_printf(MSG_DEBUG, "EAP-SAKE: Initialized Session ID %d",
  76                    data->session_id);
  77
  78         return data;
  79 }
  80
  81
  82 static void eap_sake_reset(struct eap_sm *sm, void *priv)
  83 {
  84         struct eap_sake_data *data = priv;
  85         os_free(data->peerid);
  86         bin_clear_free(data, sizeof(*data));
  87 }
  88
  89
  90 static struct wpabuf * eap_sake_build_msg(struct eap_sake_data *data,
  91                                           u8 id, size_t length, u8 subtype)
  92 {
  93         struct eap_sake_hdr *sake;
  94         struct wpabuf *msg;
  95         size_t plen;
  96
  97         plen = sizeof(struct eap_sake_hdr) + length;
  98
  99         msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_SAKE, plen,
 100                             EAP_CODE_REQUEST, id);
 101         if (msg == NULL) {
 102                 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to allocate memory "
 103                            "request");
 104                 return NULL;
 105         }
 106
 107         sake = wpabuf_put(msg, sizeof(*sake));
 108         sake->version = EAP_SAKE_VERSION;
 109         sake->session_id = data->session_id;
 110         sake->subtype = subtype;
 111
 112         return msg;
 113 }
 114
 115
 116 static struct wpabuf * eap_sake_build_identity(struct eap_sm *sm,
 117                                                struct eap_sake_data *data,
 118                                                u8 id)
 119 {
 120         struct wpabuf *msg;
 121         size_t plen;
 122
 123         wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Identity");
 124
 125         plen = 4;
 126         plen += 2 + sm->server_id_len;
 127         msg = eap_sake_build_msg(data, id, plen, EAP_SAKE_SUBTYPE_IDENTITY);
 128         if (msg == NULL) {
 129                 data->state = FAILURE;
 130                 return NULL;
 131         }
 132
 133         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PERM_ID_REQ");
 134         eap_sake_add_attr(msg, EAP_SAKE_AT_PERM_ID_REQ, NULL, 2);
 135
 136         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID");
 137         eap_sake_add_attr(msg, EAP_SAKE_AT_SERVERID,
 138                           sm->server_id, sm->server_id_len);
 139
 140         return msg;
 141 }
 142
 143
 144 static struct wpabuf * eap_sake_build_challenge(struct eap_sm *sm,
 145                                                 struct eap_sake_data *data,
 146                                                 u8 id)
 147 {
 148         struct wpabuf *msg;
 149         size_t plen;
 150
 151         wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge");
 152
 153         if (random_get_bytes(data->rand_s, EAP_SAKE_RAND_LEN)) {
 154                 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
 155                 data->state = FAILURE;
 156                 return NULL;
 157         }
 158         wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)",
 159                     data->rand_s, EAP_SAKE_RAND_LEN);
 160
 161         plen = 2 + EAP_SAKE_RAND_LEN + 2 + sm->server_id_len;
 162         msg = eap_sake_build_msg(data, id, plen, EAP_SAKE_SUBTYPE_CHALLENGE);
 163         if (msg == NULL) {
 164                 data->state = FAILURE;
 165                 return NULL;
 166         }
 167
 168         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_S");
 169         eap_sake_add_attr(msg, EAP_SAKE_AT_RAND_S,
 170                           data->rand_s, EAP_SAKE_RAND_LEN);
 171
 172         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID");
 173         eap_sake_add_attr(msg, EAP_SAKE_AT_SERVERID,
 174                           sm->server_id, sm->server_id_len);
 175
 176         return msg;
 177 }
 178
 179
 180 static struct wpabuf * eap_sake_build_confirm(struct eap_sm *sm,
 181                                               struct eap_sake_data *data,
 182                                               u8 id)
 183 {
 184         struct wpabuf *msg;
 185         u8 *mic;
 186
 187         wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Confirm");
 188
 189         msg = eap_sake_build_msg(data, id, 2 + EAP_SAKE_MIC_LEN,
 190                                  EAP_SAKE_SUBTYPE_CONFIRM);
 191         if (msg == NULL) {
 192                 data->state = FAILURE;
 193                 return NULL;
 194         }
 195
 196         wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_S");
 197         wpabuf_put_u8(msg, EAP_SAKE_AT_MIC_S);
 198         wpabuf_put_u8(msg, 2 + EAP_SAKE_MIC_LEN);
 199         mic = wpabuf_put(msg, EAP_SAKE_MIC_LEN);
 200         if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 201                                  sm->server_id, sm->server_id_len,
 202                                  data->peerid, data->peerid_len, 0,
 203                                  wpabuf_head(msg), wpabuf_len(msg), mic, mic))
 204         {
 205                 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
 206                 data->state = FAILURE;
 207                 wpabuf_free(msg);
 208                 return NULL;
 209         }
 210
 211         return msg;
 212 }
 213
 214
 215 static struct wpabuf * eap_sake_buildReq(struct eap_sm *sm, void *priv, u8 id)
 216 {
 217         struct eap_sake_data *data = priv;
 218
 219         switch (data->state) {
 220         case IDENTITY:
 221                 return eap_sake_build_identity(sm, data, id);
 222         case CHALLENGE:
 223                 return eap_sake_build_challenge(sm, data, id);
 224         case CONFIRM:
 225                 return eap_sake_build_confirm(sm, data, id);
 226         default:
 227                 wpa_printf(MSG_DEBUG, "EAP-SAKE: Unknown state %d in buildReq",
 228                            data->state);
 229                 break;
 230         }
 231         return NULL;
 232 }
 233
 234
 235 static Boolean eap_sake_check(struct eap_sm *sm, void *priv,
 236                               struct wpabuf *respData)
 237 {
 238         struct eap_sake_data *data = priv;
 239         struct eap_sake_hdr *resp;
 240         size_t len;
 241         u8 version, session_id, subtype;
 242         const u8 *pos;
 243
 244         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, respData, &len);
 245         if (pos == NULL || len < sizeof(struct eap_sake_hdr)) {
 246                 wpa_printf(MSG_INFO, "EAP-SAKE: Invalid frame");
 247                 return TRUE;
 248         }
 249
 250         resp = (struct eap_sake_hdr *) pos;
 251         version = resp->version;
 252         session_id = resp->session_id;
 253         subtype = resp->subtype;
 254
 255         if (version != EAP_SAKE_VERSION) {
 256                 wpa_printf(MSG_INFO, "EAP-SAKE: Unknown version %d", version);
 257                 return TRUE;
 258         }
 259
 260         if (session_id != data->session_id) {
 261                 wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
 262                            session_id, data->session_id);
 263                 return TRUE;
 264         }
 265
 266         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype=%d", subtype);
 267
 268         if (data->state == IDENTITY && subtype == EAP_SAKE_SUBTYPE_IDENTITY)
 269                 return FALSE;
 270
 271         if (data->state == CHALLENGE && subtype == EAP_SAKE_SUBTYPE_CHALLENGE)
 272                 return FALSE;
 273
 274         if (data->state == CONFIRM && subtype == EAP_SAKE_SUBTYPE_CONFIRM)
 275                 return FALSE;
 276
 277         if (subtype == EAP_SAKE_SUBTYPE_AUTH_REJECT)
 278                 return FALSE;
 279
 280         wpa_printf(MSG_INFO, "EAP-SAKE: Unexpected subtype=%d in state=%d",
 281                    subtype, data->state);
 282
 283         return TRUE;
 284 }
 285
 286
 287 static void eap_sake_process_identity(struct eap_sm *sm,
 288                                       struct eap_sake_data *data,
 289                                       const struct wpabuf *respData,
 290                                       const u8 *payload, size_t payloadlen)
 291 {
 292         if (data->state != IDENTITY)
 293                 return;
 294
 295         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Identity");
 296         /* TODO: update identity and select new user data */
 297         eap_sake_state(data, CHALLENGE);
 298 }
 299
 300
 301 static void eap_sake_process_challenge(struct eap_sm *sm,
 302                                        struct eap_sake_data *data,
 303                                        const struct wpabuf *respData,
 304                                        const u8 *payload, size_t payloadlen)
 305 {
 306         struct eap_sake_parse_attr attr;
 307         u8 mic_p[EAP_SAKE_MIC_LEN];
 308
 309         if (data->state != CHALLENGE)
 310                 return;
 311
 312         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Challenge");
 313
 314         if (eap_sake_parse_attributes(payload, payloadlen, &attr))
 315                 return;
 316
 317         if (!attr.rand_p || !attr.mic_p) {
 318                 wpa_printf(MSG_INFO, "EAP-SAKE: Response/Challenge did not "
 319                            "include AT_RAND_P or AT_MIC_P");
 320                 return;
 321         }
 322
 323         os_memcpy(data->rand_p, attr.rand_p, EAP_SAKE_RAND_LEN);
 324
 325         os_free(data->peerid);
 326         data->peerid = NULL;
 327         data->peerid_len = 0;
 328         if (attr.peerid) {
 329                 data->peerid = os_memdup(attr.peerid, attr.peerid_len);
 330                 if (data->peerid == NULL)
 331                         return;
 332                 data->peerid_len = attr.peerid_len;
 333         }
 334
 335         if (sm->user == NULL || sm->user->password == NULL ||
 336             sm->user->password_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) {
 337                 wpa_printf(MSG_INFO, "EAP-SAKE: Plaintext password with "
 338                            "%d-byte key not configured",
 339                            2 * EAP_SAKE_ROOT_SECRET_LEN);
 340                 data->state = FAILURE;
 341                 return;
 342         }
 343         eap_sake_derive_keys(sm->user->password,
 344                              sm->user->password + EAP_SAKE_ROOT_SECRET_LEN,
 345                              data->rand_s, data->rand_p,
 346                              (u8 *) &data->tek, data->msk, data->emsk);
 347
 348         eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 349                              sm->server_id, sm->server_id_len,
 350                              data->peerid, data->peerid_len, 1,
 351                              wpabuf_head(respData), wpabuf_len(respData),
 352                              attr.mic_p, mic_p);
 353         if (os_memcmp_const(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
 354                 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
 355                 eap_sake_state(data, FAILURE);
 356                 return;
 357         }
 358
 359         eap_sake_state(data, CONFIRM);
 360 }
 361
 362
 363 static void eap_sake_process_confirm(struct eap_sm *sm,
 364                                      struct eap_sake_data *data,
 365                                      const struct wpabuf *respData,
 366                                      const u8 *payload, size_t payloadlen)
 367 {
 368         struct eap_sake_parse_attr attr;
 369         u8 mic_p[EAP_SAKE_MIC_LEN];
 370
 371         if (data->state != CONFIRM)
 372                 return;
 373
 374         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Confirm");
 375
 376         if (eap_sake_parse_attributes(payload, payloadlen, &attr))
 377                 return;
 378
 379         if (!attr.mic_p) {
 380                 wpa_printf(MSG_INFO, "EAP-SAKE: Response/Confirm did not "
 381                            "include AT_MIC_P");
 382                 return;
 383         }
 384
 385         eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
 386                              sm->server_id, sm->server_id_len,
 387                              data->peerid, data->peerid_len, 1,
 388                              wpabuf_head(respData), wpabuf_len(respData),
 389                              attr.mic_p, mic_p);
 390         if (os_memcmp_const(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
 391                 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
 392                 eap_sake_state(data, FAILURE);
 393         } else
 394                 eap_sake_state(data, SUCCESS);
 395 }
 396
 397
 398 static void eap_sake_process_auth_reject(struct eap_sm *sm,
 399                                          struct eap_sake_data *data,
 400                                          const struct wpabuf *respData,
 401                                          const u8 *payload, size_t payloadlen)
 402 {
 403         wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Auth-Reject");
 404         eap_sake_state(data, FAILURE);
 405 }
 406
 407
 408 static void eap_sake_process(struct eap_sm *sm, void *priv,
 409                              struct wpabuf *respData)
 410 {
 411         struct eap_sake_data *data = priv;
 412         struct eap_sake_hdr *resp;
 413         u8 subtype;
 414         size_t len;
 415         const u8 *pos, *end;
 416
 417         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, respData, &len);
 418         if (pos == NULL || len < sizeof(struct eap_sake_hdr))
 419                 return;
 420
 421         resp = (struct eap_sake_hdr *) pos;
 422         end = pos + len;
 423         subtype = resp->subtype;
 424         pos = (u8 *) (resp + 1);
 425
 426         wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
 427                     pos, end - pos);
 428
 429         switch (subtype) {
 430         case EAP_SAKE_SUBTYPE_IDENTITY:
 431                 eap_sake_process_identity(sm, data, respData, pos, end - pos);
 432                 break;
 433         case EAP_SAKE_SUBTYPE_CHALLENGE:
 434                 eap_sake_process_challenge(sm, data, respData, pos, end - pos);
 435                 break;
 436         case EAP_SAKE_SUBTYPE_CONFIRM:
 437                 eap_sake_process_confirm(sm, data, respData, pos, end - pos);
 438                 break;
 439         case EAP_SAKE_SUBTYPE_AUTH_REJECT:
 440                 eap_sake_process_auth_reject(sm, data, respData, pos,
 441                                              end - pos);
 442                 break;
 443         }
 444 }
 445
 446
 447 static Boolean eap_sake_isDone(struct eap_sm *sm, void *priv)
 448 {
 449         struct eap_sake_data *data = priv;
 450         return data->state == SUCCESS || data->state == FAILURE;
 451 }
 452
 453
 454 static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len)
 455 {
 456         struct eap_sake_data *data = priv;
 457         u8 *key;
 458
 459         if (data->state != SUCCESS)
 460                 return NULL;
 461
 462         key = os_memdup(data->msk, EAP_MSK_LEN);
 463         if (key == NULL)
 464                 return NULL;
 465         *len = EAP_MSK_LEN;
 466
 467         return key;
 468 }
 469
 470
 471 static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 472 {
 473         struct eap_sake_data *data = priv;
 474         u8 *key;
 475
 476         if (data->state != SUCCESS)
 477                 return NULL;
 478
 479         key = os_memdup(data->emsk, EAP_EMSK_LEN);
 480         if (key == NULL)
 481                 return NULL;
 482         *len = EAP_EMSK_LEN;
 483
 484         return key;
 485 }
 486
 487
 488 static Boolean eap_sake_isSuccess(struct eap_sm *sm, void *priv)
 489 {
 490         struct eap_sake_data *data = priv;
 491         return data->state == SUCCESS;
 492 }
 493
 494
 495 static u8 * eap_sake_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
 496 {
 497         struct eap_sake_data *data = priv;
 498         u8 *id;
 499
 500         if (data->state != SUCCESS)
 501                 return NULL;
 502
 503         *len = 1 + 2 * EAP_SAKE_RAND_LEN;
 504         id = os_malloc(*len);
 505         if (id == NULL)
 506                 return NULL;
 507
 508         id[0] = EAP_TYPE_SAKE;
 509         os_memcpy(id + 1, data->rand_s, EAP_SAKE_RAND_LEN);
 510         os_memcpy(id + 1 + EAP_SAKE_RAND_LEN, data->rand_s, EAP_SAKE_RAND_LEN);
 511         wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Derived Session-Id", id, *len);
 512
 513         return id;
 514 }
 515
 516
 517 int eap_server_sake_register(void)
 518 {
 519         struct eap_method *eap;
 520
 521         eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
 522                                       EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE");
 523         if (eap == NULL)
 524                 return -1;
 525
 526         eap->init = eap_sake_init;
 527         eap->reset = eap_sake_reset;
 528         eap->buildReq = eap_sake_buildReq;
 529         eap->check = eap_sake_check;
 530         eap->process = eap_sake_process;
 531         eap->isDone = eap_sake_isDone;
 532         eap->getKey = eap_sake_getKey;
 533         eap->isSuccess = eap_sake_isSuccess;
 534         eap->get_emsk = eap_sake_get_emsk;
 535         eap->getSessionId = eap_sake_get_session_id;
 536
 537         return eap_server_method_register(eap);
 538 }