1 /* 2 * EAP peer method: EAP-SAKE (RFC 4763) 3 * Copyright (c) 2006-2008, 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_peer/eap_i.h" 14 #include "eap_common/eap_sake_common.h" 15 16 struct eap_sake_data { 17 enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state; 18 u8 root_secret_a[EAP_SAKE_ROOT_SECRET_LEN]; 19 u8 root_secret_b[EAP_SAKE_ROOT_SECRET_LEN]; 20 u8 rand_s[EAP_SAKE_RAND_LEN]; 21 u8 rand_p[EAP_SAKE_RAND_LEN]; 22 struct { 23 u8 auth[EAP_SAKE_TEK_AUTH_LEN]; 24 u8 cipher[EAP_SAKE_TEK_CIPHER_LEN]; 25 } tek; 26 u8 msk[EAP_MSK_LEN]; 27 u8 emsk[EAP_EMSK_LEN]; 28 u8 session_id; 29 int session_id_set; 30 u8 *peerid; 31 size_t peerid_len; 32 u8 *serverid; 33 size_t serverid_len; 34 }; 35 36 37 static const char * eap_sake_state_txt(int state) 38 { 39 switch (state) { 40 case IDENTITY: 41 return "IDENTITY"; 42 case CHALLENGE: 43 return "CHALLENGE"; 44 case CONFIRM: 45 return "CONFIRM"; 46 case SUCCESS: 47 return "SUCCESS"; 48 case FAILURE: 49 return "FAILURE"; 50 default: 51 return "?"; 52 } 53 } 54 55 56 static void eap_sake_state(struct eap_sake_data *data, int state) 57 { 58 wpa_printf(MSG_DEBUG, "EAP-SAKE: %s -> %s", 59 eap_sake_state_txt(data->state), 60 eap_sake_state_txt(state)); 61 data->state = state; 62 } 63 64 65 static void eap_sake_deinit(struct eap_sm *sm, void *priv); 66 67 68 static void * eap_sake_init(struct eap_sm *sm) 69 { 70 struct eap_sake_data *data; 71 const u8 *identity, *password; 72 size_t identity_len, password_len; 73 74 password = eap_get_config_password(sm, &password_len); 75 if (!password || password_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) { 76 wpa_printf(MSG_INFO, "EAP-SAKE: No key of correct length " 77 "configured"); 78 return NULL; 79 } 80 81 data = os_zalloc(sizeof(*data)); 82 if (data == NULL) 83 return NULL; 84 data->state = IDENTITY; 85 86 identity = eap_get_config_identity(sm, &identity_len); 87 if (identity) { 88 data->peerid = os_malloc(identity_len); 89 if (data->peerid == NULL) { 90 eap_sake_deinit(sm, data); 91 return NULL; 92 } 93 os_memcpy(data->peerid, identity, identity_len); 94 data->peerid_len = identity_len; 95 } 96 97 os_memcpy(data->root_secret_a, password, EAP_SAKE_ROOT_SECRET_LEN); 98 os_memcpy(data->root_secret_b, 99 password + EAP_SAKE_ROOT_SECRET_LEN, 100 EAP_SAKE_ROOT_SECRET_LEN); 101 102 return data; 103 } 104 105 106 static void eap_sake_deinit(struct eap_sm *sm, void *priv) 107 { 108 struct eap_sake_data *data = priv; 109 os_free(data->serverid); 110 os_free(data->peerid); 111 os_free(data); 112 } 113 114 115 static struct wpabuf * eap_sake_build_msg(struct eap_sake_data *data, 116 int id, size_t length, u8 subtype) 117 { 118 struct eap_sake_hdr *sake; 119 struct wpabuf *msg; 120 size_t plen; 121 122 plen = length + sizeof(struct eap_sake_hdr); 123 124 msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_SAKE, plen, 125 EAP_CODE_RESPONSE, id); 126 if (msg == NULL) { 127 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to allocate memory " 128 "request"); 129 return NULL; 130 } 131 132 sake = wpabuf_put(msg, sizeof(*sake)); 133 sake->version = EAP_SAKE_VERSION; 134 sake->session_id = data->session_id; 135 sake->subtype = subtype; 136 137 return msg; 138 } 139 140 141 static struct wpabuf * eap_sake_process_identity(struct eap_sm *sm, 142 struct eap_sake_data *data, 143 struct eap_method_ret *ret, 144 const struct wpabuf *reqData, 145 const u8 *payload, 146 size_t payload_len) 147 { 148 struct eap_sake_parse_attr attr; 149 struct wpabuf *resp; 150 151 if (data->state != IDENTITY) { 152 ret->ignore = TRUE; 153 return NULL; 154 } 155 156 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Identity"); 157 158 if (eap_sake_parse_attributes(payload, payload_len, &attr)) 159 return NULL; 160 161 if (!attr.perm_id_req && !attr.any_id_req) { 162 wpa_printf(MSG_INFO, "EAP-SAKE: No AT_PERM_ID_REQ or " 163 "AT_ANY_ID_REQ in Request/Identity"); 164 return NULL; 165 } 166 167 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Identity"); 168 169 resp = eap_sake_build_msg(data, eap_get_id(reqData), 170 2 + data->peerid_len, 171 EAP_SAKE_SUBTYPE_IDENTITY); 172 if (resp == NULL) 173 return NULL; 174 175 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID"); 176 eap_sake_add_attr(resp, EAP_SAKE_AT_PEERID, 177 data->peerid, data->peerid_len); 178 179 eap_sake_state(data, CHALLENGE); 180 181 return resp; 182 } 183 184 185 static struct wpabuf * eap_sake_process_challenge(struct eap_sm *sm, 186 struct eap_sake_data *data, 187 struct eap_method_ret *ret, 188 const struct wpabuf *reqData, 189 const u8 *payload, 190 size_t payload_len) 191 { 192 struct eap_sake_parse_attr attr; 193 struct wpabuf *resp; 194 u8 *rpos; 195 size_t rlen; 196 197 if (data->state != IDENTITY && data->state != CHALLENGE) { 198 wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge received " 199 "in unexpected state (%d)", data->state); 200 ret->ignore = TRUE; 201 return NULL; 202 } 203 if (data->state == IDENTITY) 204 eap_sake_state(data, CHALLENGE); 205 206 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Challenge"); 207 208 if (eap_sake_parse_attributes(payload, payload_len, &attr)) 209 return NULL; 210 211 if (!attr.rand_s) { 212 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Challenge did not " 213 "include AT_RAND_S"); 214 return NULL; 215 } 216 217 os_memcpy(data->rand_s, attr.rand_s, EAP_SAKE_RAND_LEN); 218 wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)", 219 data->rand_s, EAP_SAKE_RAND_LEN); 220 221 if (random_get_bytes(data->rand_p, EAP_SAKE_RAND_LEN)) { 222 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data"); 223 return NULL; 224 } 225 wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_P (peer rand)", 226 data->rand_p, EAP_SAKE_RAND_LEN); 227 228 os_free(data->serverid); 229 data->serverid = NULL; 230 data->serverid_len = 0; 231 if (attr.serverid) { 232 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-SAKE: SERVERID", 233 attr.serverid, attr.serverid_len); 234 data->serverid = os_malloc(attr.serverid_len); 235 if (data->serverid == NULL) 236 return NULL; 237 os_memcpy(data->serverid, attr.serverid, attr.serverid_len); 238 data->serverid_len = attr.serverid_len; 239 } 240 241 eap_sake_derive_keys(data->root_secret_a, data->root_secret_b, 242 data->rand_s, data->rand_p, 243 (u8 *) &data->tek, data->msk, data->emsk); 244 245 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Challenge"); 246 247 rlen = 2 + EAP_SAKE_RAND_LEN + 2 + EAP_SAKE_MIC_LEN; 248 if (data->peerid) 249 rlen += 2 + data->peerid_len; 250 resp = eap_sake_build_msg(data, eap_get_id(reqData), rlen, 251 EAP_SAKE_SUBTYPE_CHALLENGE); 252 if (resp == NULL) 253 return NULL; 254 255 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_P"); 256 eap_sake_add_attr(resp, EAP_SAKE_AT_RAND_P, 257 data->rand_p, EAP_SAKE_RAND_LEN); 258 259 if (data->peerid) { 260 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID"); 261 eap_sake_add_attr(resp, EAP_SAKE_AT_PEERID, 262 data->peerid, data->peerid_len); 263 } 264 265 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P"); 266 wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P); 267 wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN); 268 rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN); 269 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p, 270 data->serverid, data->serverid_len, 271 data->peerid, data->peerid_len, 1, 272 wpabuf_head(resp), wpabuf_len(resp), rpos, 273 rpos)) { 274 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC"); 275 wpabuf_free(resp); 276 return NULL; 277 } 278 279 eap_sake_state(data, CONFIRM); 280 281 return resp; 282 } 283 284 285 static struct wpabuf * eap_sake_process_confirm(struct eap_sm *sm, 286 struct eap_sake_data *data, 287 struct eap_method_ret *ret, 288 const struct wpabuf *reqData, 289 const u8 *payload, 290 size_t payload_len) 291 { 292 struct eap_sake_parse_attr attr; 293 u8 mic_s[EAP_SAKE_MIC_LEN]; 294 struct wpabuf *resp; 295 u8 *rpos; 296 297 if (data->state != CONFIRM) { 298 ret->ignore = TRUE; 299 return NULL; 300 } 301 302 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Confirm"); 303 304 if (eap_sake_parse_attributes(payload, payload_len, &attr)) 305 return NULL; 306 307 if (!attr.mic_s) { 308 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Confirm did not " 309 "include AT_MIC_S"); 310 return NULL; 311 } 312 313 eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p, 314 data->serverid, data->serverid_len, 315 data->peerid, data->peerid_len, 0, 316 wpabuf_head(reqData), wpabuf_len(reqData), 317 attr.mic_s, mic_s); 318 if (os_memcmp(attr.mic_s, mic_s, EAP_SAKE_MIC_LEN) != 0) { 319 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_S"); 320 eap_sake_state(data, FAILURE); 321 ret->methodState = METHOD_DONE; 322 ret->decision = DECISION_FAIL; 323 ret->allowNotifications = FALSE; 324 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending " 325 "Response/Auth-Reject"); 326 return eap_sake_build_msg(data, eap_get_id(reqData), 0, 327 EAP_SAKE_SUBTYPE_AUTH_REJECT); 328 } 329 330 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Confirm"); 331 332 resp = eap_sake_build_msg(data, eap_get_id(reqData), 333 2 + EAP_SAKE_MIC_LEN, 334 EAP_SAKE_SUBTYPE_CONFIRM); 335 if (resp == NULL) 336 return NULL; 337 338 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P"); 339 wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P); 340 wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN); 341 rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN); 342 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p, 343 data->serverid, data->serverid_len, 344 data->peerid, data->peerid_len, 1, 345 wpabuf_head(resp), wpabuf_len(resp), rpos, 346 rpos)) { 347 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC"); 348 wpabuf_free(resp); 349 return NULL; 350 } 351 352 eap_sake_state(data, SUCCESS); 353 ret->methodState = METHOD_DONE; 354 ret->decision = DECISION_UNCOND_SUCC; 355 ret->allowNotifications = FALSE; 356 357 return resp; 358 } 359 360 361 static struct wpabuf * eap_sake_process(struct eap_sm *sm, void *priv, 362 struct eap_method_ret *ret, 363 const struct wpabuf *reqData) 364 { 365 struct eap_sake_data *data = priv; 366 const struct eap_sake_hdr *req; 367 struct wpabuf *resp; 368 const u8 *pos, *end; 369 size_t len; 370 u8 subtype, session_id; 371 372 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, reqData, &len); 373 if (pos == NULL || len < sizeof(struct eap_sake_hdr)) { 374 ret->ignore = TRUE; 375 return NULL; 376 } 377 378 req = (const struct eap_sake_hdr *) pos; 379 end = pos + len; 380 subtype = req->subtype; 381 session_id = req->session_id; 382 pos = (const u8 *) (req + 1); 383 384 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype %d " 385 "session_id %d", subtype, session_id); 386 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes", 387 pos, end - pos); 388 389 if (data->session_id_set && data->session_id != session_id) { 390 wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)", 391 session_id, data->session_id); 392 ret->ignore = TRUE; 393 return NULL; 394 } 395 data->session_id = session_id; 396 data->session_id_set = 1; 397 398 ret->ignore = FALSE; 399 ret->methodState = METHOD_MAY_CONT; 400 ret->decision = DECISION_FAIL; 401 ret->allowNotifications = TRUE; 402 403 switch (subtype) { 404 case EAP_SAKE_SUBTYPE_IDENTITY: 405 resp = eap_sake_process_identity(sm, data, ret, reqData, 406 pos, end - pos); 407 break; 408 case EAP_SAKE_SUBTYPE_CHALLENGE: 409 resp = eap_sake_process_challenge(sm, data, ret, reqData, 410 pos, end - pos); 411 break; 412 case EAP_SAKE_SUBTYPE_CONFIRM: 413 resp = eap_sake_process_confirm(sm, data, ret, reqData, 414 pos, end - pos); 415 break; 416 default: 417 wpa_printf(MSG_DEBUG, "EAP-SAKE: Ignoring message with " 418 "unknown subtype %d", subtype); 419 ret->ignore = TRUE; 420 return NULL; 421 } 422 423 if (ret->methodState == METHOD_DONE) 424 ret->allowNotifications = FALSE; 425 426 return resp; 427 } 428 429 430 static Boolean eap_sake_isKeyAvailable(struct eap_sm *sm, void *priv) 431 { 432 struct eap_sake_data *data = priv; 433 return data->state == SUCCESS; 434 } 435 436 437 static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len) 438 { 439 struct eap_sake_data *data = priv; 440 u8 *key; 441 442 if (data->state != SUCCESS) 443 return NULL; 444 445 key = os_malloc(EAP_MSK_LEN); 446 if (key == NULL) 447 return NULL; 448 os_memcpy(key, data->msk, EAP_MSK_LEN); 449 *len = EAP_MSK_LEN; 450 451 return key; 452 } 453 454 455 static u8 * eap_sake_get_session_id(struct eap_sm *sm, void *priv, size_t *len) 456 { 457 struct eap_sake_data *data = priv; 458 u8 *id; 459 460 if (data->state != SUCCESS) 461 return NULL; 462 463 *len = 1 + 2 * EAP_SAKE_RAND_LEN; 464 id = os_malloc(*len); 465 if (id == NULL) 466 return NULL; 467 468 id[0] = EAP_TYPE_SAKE; 469 os_memcpy(id + 1, data->rand_s, EAP_SAKE_RAND_LEN); 470 os_memcpy(id + 1 + EAP_SAKE_RAND_LEN, data->rand_s, EAP_SAKE_RAND_LEN); 471 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Derived Session-Id", id, *len); 472 473 return id; 474 } 475 476 477 static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len) 478 { 479 struct eap_sake_data *data = priv; 480 u8 *key; 481 482 if (data->state != SUCCESS) 483 return NULL; 484 485 key = os_malloc(EAP_EMSK_LEN); 486 if (key == NULL) 487 return NULL; 488 os_memcpy(key, data->emsk, EAP_EMSK_LEN); 489 *len = EAP_EMSK_LEN; 490 491 return key; 492 } 493 494 495 int eap_peer_sake_register(void) 496 { 497 struct eap_method *eap; 498 int ret; 499 500 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION, 501 EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE"); 502 if (eap == NULL) 503 return -1; 504 505 eap->init = eap_sake_init; 506 eap->deinit = eap_sake_deinit; 507 eap->process = eap_sake_process; 508 eap->isKeyAvailable = eap_sake_isKeyAvailable; 509 eap->getKey = eap_sake_getKey; 510 eap->getSessionId = eap_sake_get_session_id; 511 eap->get_emsk = eap_sake_get_emsk; 512 513 ret = eap_peer_method_register(eap); 514 if (ret) 515 eap_peer_method_free(eap); 516 return ret; 517 } 518