1 /* 2 * hostapd / EAP-MSCHAPv2 (draft-kamath-pppext-eap-mschapv2-00.txt) server 3 * Copyright (c) 2004-2007, Jouni Malinen <j (at) 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/ms_funcs.h" 13 #include "crypto/random.h" 14 #include "eap_i.h" 15 16 17 struct eap_mschapv2_hdr { 18 u8 op_code; /* MSCHAPV2_OP_* */ 19 u8 mschapv2_id; /* must be changed for challenges, but not for 20 * success/failure */ 21 u8 ms_length[2]; /* Note: misaligned; length - 5 */ 22 /* followed by data */ 23 } STRUCT_PACKED; 24 25 #define MSCHAPV2_OP_CHALLENGE 1 26 #define MSCHAPV2_OP_RESPONSE 2 27 #define MSCHAPV2_OP_SUCCESS 3 28 #define MSCHAPV2_OP_FAILURE 4 29 #define MSCHAPV2_OP_CHANGE_PASSWORD 7 30 31 #define MSCHAPV2_RESP_LEN 49 32 33 #define ERROR_RESTRICTED_LOGON_HOURS 646 34 #define ERROR_ACCT_DISABLED 647 35 #define ERROR_PASSWD_EXPIRED 648 36 #define ERROR_NO_DIALIN_PERMISSION 649 37 #define ERROR_AUTHENTICATION_FAILURE 691 38 #define ERROR_CHANGING_PASSWORD 709 39 40 #define PASSWD_CHANGE_CHAL_LEN 16 41 #define MSCHAPV2_KEY_LEN 16 42 43 44 #define CHALLENGE_LEN 16 45 46 struct eap_mschapv2_data { 47 u8 auth_challenge[CHALLENGE_LEN]; 48 int auth_challenge_from_tls; 49 u8 *peer_challenge; 50 u8 auth_response[20]; 51 enum { CHALLENGE, SUCCESS_REQ, FAILURE_REQ, SUCCESS, FAILURE } state; 52 u8 resp_mschapv2_id; 53 u8 master_key[16]; 54 int master_key_valid; 55 }; 56 57 58 static void * eap_mschapv2_init(struct eap_sm *sm) 59 { 60 struct eap_mschapv2_data *data; 61 62 data = os_zalloc(sizeof(*data)); 63 if (data == NULL) 64 return NULL; 65 data->state = CHALLENGE; 66 67 if (sm->auth_challenge) { 68 os_memcpy(data->auth_challenge, sm->auth_challenge, 69 CHALLENGE_LEN); 70 data->auth_challenge_from_tls = 1; 71 } 72 73 if (sm->peer_challenge) { 74 data->peer_challenge = os_malloc(CHALLENGE_LEN); 75 if (data->peer_challenge == NULL) { 76 os_free(data); 77 return NULL; 78 } 79 os_memcpy(data->peer_challenge, sm->peer_challenge, 80 CHALLENGE_LEN); 81 } 82 83 return data; 84 } 85 86 87 static void eap_mschapv2_reset(struct eap_sm *sm, void *priv) 88 { 89 struct eap_mschapv2_data *data = priv; 90 if (data == NULL) 91 return; 92 93 os_free(data->peer_challenge); 94 bin_clear_free(data, sizeof(*data)); 95 } 96 97 98 static struct wpabuf * eap_mschapv2_build_challenge( 99 struct eap_sm *sm, struct eap_mschapv2_data *data, u8 id) 100 { 101 struct wpabuf *req; 102 struct eap_mschapv2_hdr *ms; 103 size_t ms_len; 104 105 if (!data->auth_challenge_from_tls && 106 random_get_bytes(data->auth_challenge, CHALLENGE_LEN)) { 107 wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to get random " 108 "data"); 109 data->state = FAILURE; 110 return NULL; 111 } 112 113 ms_len = sizeof(*ms) + 1 + CHALLENGE_LEN + sm->server_id_len; 114 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, ms_len, 115 EAP_CODE_REQUEST, id); 116 if (req == NULL) { 117 wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to allocate memory" 118 " for request"); 119 data->state = FAILURE; 120 return NULL; 121 } 122 123 ms = wpabuf_put(req, sizeof(*ms)); 124 ms->op_code = MSCHAPV2_OP_CHALLENGE; 125 ms->mschapv2_id = id; 126 WPA_PUT_BE16(ms->ms_length, ms_len); 127 128 wpabuf_put_u8(req, CHALLENGE_LEN); 129 if (!data->auth_challenge_from_tls) 130 wpabuf_put_data(req, data->auth_challenge, CHALLENGE_LEN); 131 else 132 wpabuf_put(req, CHALLENGE_LEN); 133 wpa_hexdump(MSG_MSGDUMP, "EAP-MSCHAPV2: Challenge", 134 data->auth_challenge, CHALLENGE_LEN); 135 wpabuf_put_data(req, sm->server_id, sm->server_id_len); 136 137 return req; 138 } 139 140 141 static struct wpabuf * eap_mschapv2_build_success_req( 142 struct eap_sm *sm, struct eap_mschapv2_data *data, u8 id) 143 { 144 struct wpabuf *req; 145 struct eap_mschapv2_hdr *ms; 146 u8 *msg; 147 char *message = "OK"; 148 size_t ms_len; 149 150 ms_len = sizeof(*ms) + 2 + 2 * sizeof(data->auth_response) + 1 + 2 + 151 os_strlen(message); 152 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, ms_len, 153 EAP_CODE_REQUEST, id); 154 if (req == NULL) { 155 wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to allocate memory" 156 " for request"); 157 data->state = FAILURE; 158 return NULL; 159 } 160 161 ms = wpabuf_put(req, sizeof(*ms)); 162 ms->op_code = MSCHAPV2_OP_SUCCESS; 163 ms->mschapv2_id = data->resp_mschapv2_id; 164 WPA_PUT_BE16(ms->ms_length, ms_len); 165 msg = (u8 *) (ms + 1); 166 167 wpabuf_put_u8(req, 'S'); 168 wpabuf_put_u8(req, '='); 169 wpa_snprintf_hex_uppercase( 170 wpabuf_put(req, sizeof(data->auth_response) * 2), 171 sizeof(data->auth_response) * 2 + 1, 172 data->auth_response, sizeof(data->auth_response)); 173 wpabuf_put_u8(req, ' '); 174 wpabuf_put_u8(req, 'M'); 175 wpabuf_put_u8(req, '='); 176 wpabuf_put_data(req, message, os_strlen(message)); 177 178 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-MSCHAPV2: Success Request Message", 179 msg, ms_len - sizeof(*ms)); 180 181 return req; 182 } 183 184 185 static struct wpabuf * eap_mschapv2_build_failure_req( 186 struct eap_sm *sm, struct eap_mschapv2_data *data, u8 id) 187 { 188 struct wpabuf *req; 189 struct eap_mschapv2_hdr *ms; 190 char *message = "E=691 R=0 C=00000000000000000000000000000000 V=3 " 191 "M=FAILED"; 192 size_t ms_len; 193 194 ms_len = sizeof(*ms) + os_strlen(message); 195 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, ms_len, 196 EAP_CODE_REQUEST, id); 197 if (req == NULL) { 198 wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to allocate memory" 199 " for request"); 200 data->state = FAILURE; 201 return NULL; 202 } 203 204 ms = wpabuf_put(req, sizeof(*ms)); 205 ms->op_code = MSCHAPV2_OP_FAILURE; 206 ms->mschapv2_id = data->resp_mschapv2_id; 207 WPA_PUT_BE16(ms->ms_length, ms_len); 208 209 wpabuf_put_data(req, message, os_strlen(message)); 210 211 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-MSCHAPV2: Failure Request Message", 212 (u8 *) message, os_strlen(message)); 213 214 return req; 215 } 216 217 218 static struct wpabuf * eap_mschapv2_buildReq(struct eap_sm *sm, void *priv, 219 u8 id) 220 { 221 struct eap_mschapv2_data *data = priv; 222 223 switch (data->state) { 224 case CHALLENGE: 225 return eap_mschapv2_build_challenge(sm, data, id); 226 case SUCCESS_REQ: 227 return eap_mschapv2_build_success_req(sm, data, id); 228 case FAILURE_REQ: 229 return eap_mschapv2_build_failure_req(sm, data, id); 230 default: 231 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Unknown state %d in " 232 "buildReq", data->state); 233 break; 234 } 235 return NULL; 236 } 237 238 239 static Boolean eap_mschapv2_check(struct eap_sm *sm, void *priv, 240 struct wpabuf *respData) 241 { 242 struct eap_mschapv2_data *data = priv; 243 struct eap_mschapv2_hdr *resp; 244 const u8 *pos; 245 size_t len; 246 247 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, respData, 248 &len); 249 if (pos == NULL || len < 1) { 250 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Invalid frame"); 251 return TRUE; 252 } 253 254 resp = (struct eap_mschapv2_hdr *) pos; 255 if (data->state == CHALLENGE && 256 resp->op_code != MSCHAPV2_OP_RESPONSE) { 257 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Expected Response - " 258 "ignore op %d", resp->op_code); 259 return TRUE; 260 } 261 262 if (data->state == SUCCESS_REQ && 263 resp->op_code != MSCHAPV2_OP_SUCCESS && 264 resp->op_code != MSCHAPV2_OP_FAILURE) { 265 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Expected Success or " 266 "Failure - ignore op %d", resp->op_code); 267 return TRUE; 268 } 269 270 if (data->state == FAILURE_REQ && 271 resp->op_code != MSCHAPV2_OP_FAILURE) { 272 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Expected Failure " 273 "- ignore op %d", resp->op_code); 274 return TRUE; 275 } 276 277 return FALSE; 278 } 279 280 281 static void eap_mschapv2_process_response(struct eap_sm *sm, 282 struct eap_mschapv2_data *data, 283 struct wpabuf *respData) 284 { 285 struct eap_mschapv2_hdr *resp; 286 const u8 *pos, *end, *peer_challenge, *nt_response, *name; 287 u8 flags; 288 size_t len, name_len, i; 289 u8 expected[24]; 290 const u8 *username, *user; 291 size_t username_len, user_len; 292 int res; 293 char *buf; 294 295 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, respData, 296 &len); 297 if (pos == NULL || len < 1) 298 return; /* Should not happen - frame already validated */ 299 300 end = pos + len; 301 resp = (struct eap_mschapv2_hdr *) pos; 302 pos = (u8 *) (resp + 1); 303 304 if (len < sizeof(*resp) + 1 + 49 || 305 resp->op_code != MSCHAPV2_OP_RESPONSE || 306 pos[0] != 49) { 307 wpa_hexdump_buf(MSG_DEBUG, "EAP-MSCHAPV2: Invalid response", 308 respData); 309 data->state = FAILURE; 310 return; 311 } 312 data->resp_mschapv2_id = resp->mschapv2_id; 313 pos++; 314 peer_challenge = pos; 315 pos += 16 + 8; 316 nt_response = pos; 317 pos += 24; 318 flags = *pos++; 319 name = pos; 320 name_len = end - name; 321 322 if (data->peer_challenge) { 323 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Using pre-configured " 324 "Peer-Challenge"); 325 peer_challenge = data->peer_challenge; 326 } 327 wpa_hexdump(MSG_MSGDUMP, "EAP-MSCHAPV2: Peer-Challenge", 328 peer_challenge, 16); 329 wpa_hexdump(MSG_MSGDUMP, "EAP-MSCHAPV2: NT-Response", nt_response, 24); 330 wpa_printf(MSG_MSGDUMP, "EAP-MSCHAPV2: Flags 0x%x", flags); 331 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-MSCHAPV2: Name", name, name_len); 332 333 buf = os_malloc(name_len * 4 + 1); 334 if (buf) { 335 printf_encode(buf, name_len * 4 + 1, name, name_len); 336 eap_log_msg(sm, "EAP-MSCHAPV2 Name '%s'", buf); 337 os_free(buf); 338 } 339 340 /* MSCHAPv2 does not include optional domain name in the 341 * challenge-response calculation, so remove domain prefix 342 * (if present). */ 343 username = sm->identity; 344 username_len = sm->identity_len; 345 for (i = 0; i < username_len; i++) { 346 if (username[i] == '\\') { 347 username_len -= i + 1; 348 username += i + 1; 349 break; 350 } 351 } 352 353 user = name; 354 user_len = name_len; 355 for (i = 0; i < user_len; i++) { 356 if (user[i] == '\\') { 357 user_len -= i + 1; 358 user += i + 1; 359 break; 360 } 361 } 362 363 if (username_len != user_len || 364 os_memcmp(username, user, username_len) != 0) { 365 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Mismatch in user names"); 366 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Expected user " 367 "name", username, username_len); 368 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Received user " 369 "name", user, user_len); 370 data->state = FAILURE; 371 return; 372 } 373 374 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-MSCHAPV2: User name", 375 username, username_len); 376 377 if (sm->user->password_hash) { 378 res = generate_nt_response_pwhash(data->auth_challenge, 379 peer_challenge, 380 username, username_len, 381 sm->user->password, 382 expected); 383 } else { 384 res = generate_nt_response(data->auth_challenge, 385 peer_challenge, 386 username, username_len, 387 sm->user->password, 388 sm->user->password_len, 389 expected); 390 } 391 if (res) { 392 data->state = FAILURE; 393 return; 394 } 395 396 if (os_memcmp_const(nt_response, expected, 24) == 0) { 397 const u8 *pw_hash; 398 u8 pw_hash_buf[16], pw_hash_hash[16]; 399 400 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Correct NT-Response"); 401 data->state = SUCCESS_REQ; 402 403 /* Authenticator response is not really needed yet, but 404 * calculate it here so that peer_challenge and username need 405 * not be saved. */ 406 if (sm->user->password_hash) { 407 pw_hash = sm->user->password; 408 } else { 409 if (nt_password_hash(sm->user->password, 410 sm->user->password_len, 411 pw_hash_buf) < 0) { 412 data->state = FAILURE; 413 return; 414 } 415 pw_hash = pw_hash_buf; 416 } 417 generate_authenticator_response_pwhash( 418 pw_hash, peer_challenge, data->auth_challenge, 419 username, username_len, nt_response, 420 data->auth_response); 421 422 hash_nt_password_hash(pw_hash, pw_hash_hash); 423 get_master_key(pw_hash_hash, nt_response, data->master_key); 424 data->master_key_valid = 1; 425 wpa_hexdump_key(MSG_DEBUG, "EAP-MSCHAPV2: Derived Master Key", 426 data->master_key, MSCHAPV2_KEY_LEN); 427 } else { 428 wpa_hexdump(MSG_MSGDUMP, "EAP-MSCHAPV2: Expected NT-Response", 429 expected, 24); 430 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Invalid NT-Response"); 431 data->state = FAILURE_REQ; 432 } 433 } 434 435 436 static void eap_mschapv2_process_success_resp(struct eap_sm *sm, 437 struct eap_mschapv2_data *data, 438 struct wpabuf *respData) 439 { 440 struct eap_mschapv2_hdr *resp; 441 const u8 *pos; 442 size_t len; 443 444 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, respData, 445 &len); 446 if (pos == NULL || len < 1) 447 return; /* Should not happen - frame already validated */ 448 449 resp = (struct eap_mschapv2_hdr *) pos; 450 451 if (resp->op_code == MSCHAPV2_OP_SUCCESS) { 452 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received Success Response" 453 " - authentication completed successfully"); 454 data->state = SUCCESS; 455 } else { 456 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Did not receive Success " 457 "Response - peer rejected authentication"); 458 data->state = FAILURE; 459 } 460 } 461 462 463 static void eap_mschapv2_process_failure_resp(struct eap_sm *sm, 464 struct eap_mschapv2_data *data, 465 struct wpabuf *respData) 466 { 467 struct eap_mschapv2_hdr *resp; 468 const u8 *pos; 469 size_t len; 470 471 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, respData, 472 &len); 473 if (pos == NULL || len < 1) 474 return; /* Should not happen - frame already validated */ 475 476 resp = (struct eap_mschapv2_hdr *) pos; 477 478 if (resp->op_code == MSCHAPV2_OP_FAILURE) { 479 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received Failure Response" 480 " - authentication failed"); 481 } else { 482 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Did not receive Failure " 483 "Response - authentication failed"); 484 } 485 486 data->state = FAILURE; 487 } 488 489 490 static void eap_mschapv2_process(struct eap_sm *sm, void *priv, 491 struct wpabuf *respData) 492 { 493 struct eap_mschapv2_data *data = priv; 494 495 if (sm->user == NULL || sm->user->password == NULL) { 496 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Password not configured"); 497 data->state = FAILURE; 498 return; 499 } 500 501 switch (data->state) { 502 case CHALLENGE: 503 eap_mschapv2_process_response(sm, data, respData); 504 break; 505 case SUCCESS_REQ: 506 eap_mschapv2_process_success_resp(sm, data, respData); 507 break; 508 case FAILURE_REQ: 509 eap_mschapv2_process_failure_resp(sm, data, respData); 510 break; 511 default: 512 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Unknown state %d in " 513 "process", data->state); 514 break; 515 } 516 } 517 518 519 static Boolean eap_mschapv2_isDone(struct eap_sm *sm, void *priv) 520 { 521 struct eap_mschapv2_data *data = priv; 522 return data->state == SUCCESS || data->state == FAILURE; 523 } 524 525 526 static u8 * eap_mschapv2_getKey(struct eap_sm *sm, void *priv, size_t *len) 527 { 528 struct eap_mschapv2_data *data = priv; 529 u8 *key; 530 531 if (data->state != SUCCESS || !data->master_key_valid) 532 return NULL; 533 534 *len = 2 * MSCHAPV2_KEY_LEN; 535 key = os_malloc(*len); 536 if (key == NULL) 537 return NULL; 538 /* MSK = server MS-MPPE-Recv-Key | MS-MPPE-Send-Key */ 539 get_asymetric_start_key(data->master_key, key, MSCHAPV2_KEY_LEN, 0, 1); 540 get_asymetric_start_key(data->master_key, key + MSCHAPV2_KEY_LEN, 541 MSCHAPV2_KEY_LEN, 1, 1); 542 wpa_hexdump_key(MSG_DEBUG, "EAP-MSCHAPV2: Derived key", key, *len); 543 544 return key; 545 } 546 547 548 static Boolean eap_mschapv2_isSuccess(struct eap_sm *sm, void *priv) 549 { 550 struct eap_mschapv2_data *data = priv; 551 return data->state == SUCCESS; 552 } 553 554 555 int eap_server_mschapv2_register(void) 556 { 557 struct eap_method *eap; 558 int ret; 559 560 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION, 561 EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, 562 "MSCHAPV2"); 563 if (eap == NULL) 564 return -1; 565 566 eap->init = eap_mschapv2_init; 567 eap->reset = eap_mschapv2_reset; 568 eap->buildReq = eap_mschapv2_buildReq; 569 eap->check = eap_mschapv2_check; 570 eap->process = eap_mschapv2_process; 571 eap->isDone = eap_mschapv2_isDone; 572 eap->getKey = eap_mschapv2_getKey; 573 eap->isSuccess = eap_mschapv2_isSuccess; 574 575 ret = eap_server_method_register(eap); 576 if (ret) 577 eap_server_method_free(eap); 578 return ret; 579 } 580
