1 /* 2 * EAP peer method: EAP-MSCHAPV2 (draft-kamath-pppext-eap-mschapv2-00.txt) 3 * Copyright (c) 2004-2008, Jouni Malinen <j (at) 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 * This file implements EAP peer part of EAP-MSCHAPV2 method (EAP type 26). 15 * draft-kamath-pppext-eap-mschapv2-00.txt defines the Microsoft EAP CHAP 16 * Extensions Protocol, Version 2, for mutual authentication and key 17 * derivation. This encapsulates MS-CHAP-v2 protocol which is defined in 18 * RFC 2759. Use of EAP-MSCHAPV2 derived keys with MPPE cipher is described in 19 * RFC 3079. 20 */ 21 22 #include "includes.h" 23 24 #include "common.h" 25 #include "eap_i.h" 26 #include "eap_config.h" 27 #include "crypto/ms_funcs.h" 28 #include "wpa_ctrl.h" 29 #include "mschapv2.h" 30 31 32 #ifdef _MSC_VER 33 #pragma pack(push, 1) 34 #endif /* _MSC_VER */ 35 36 struct eap_mschapv2_hdr { 37 u8 op_code; /* MSCHAPV2_OP_* */ 38 u8 mschapv2_id; /* usually same as EAP identifier; must be changed 39 * for challenges, but not for success/failure */ 40 u8 ms_length[2]; /* Note: misaligned; length - 5 */ 41 /* followed by data */ 42 } STRUCT_PACKED; 43 44 /* Response Data field */ 45 struct ms_response { 46 u8 peer_challenge[MSCHAPV2_CHAL_LEN]; 47 u8 reserved[8]; 48 u8 nt_response[MSCHAPV2_NT_RESPONSE_LEN]; 49 u8 flags; 50 } STRUCT_PACKED; 51 52 /* Change-Password Data field */ 53 struct ms_change_password { 54 u8 encr_password[516]; 55 u8 encr_hash[16]; 56 u8 peer_challenge[MSCHAPV2_CHAL_LEN]; 57 u8 reserved[8]; 58 u8 nt_response[MSCHAPV2_NT_RESPONSE_LEN]; 59 u8 flags[2]; 60 } STRUCT_PACKED; 61 62 #ifdef _MSC_VER 63 #pragma pack(pop) 64 #endif /* _MSC_VER */ 65 66 #define MSCHAPV2_OP_CHALLENGE 1 67 #define MSCHAPV2_OP_RESPONSE 2 68 #define MSCHAPV2_OP_SUCCESS 3 69 #define MSCHAPV2_OP_FAILURE 4 70 #define MSCHAPV2_OP_CHANGE_PASSWORD 7 71 72 #define ERROR_RESTRICTED_LOGON_HOURS 646 73 #define ERROR_ACCT_DISABLED 647 74 #define ERROR_PASSWD_EXPIRED 648 75 #define ERROR_NO_DIALIN_PERMISSION 649 76 #define ERROR_AUTHENTICATION_FAILURE 691 77 #define ERROR_CHANGING_PASSWORD 709 78 79 #define PASSWD_CHANGE_CHAL_LEN 16 80 #define MSCHAPV2_KEY_LEN 16 81 82 83 struct eap_mschapv2_data { 84 u8 auth_response[MSCHAPV2_AUTH_RESPONSE_LEN]; 85 int auth_response_valid; 86 87 int prev_error; 88 u8 passwd_change_challenge[PASSWD_CHANGE_CHAL_LEN]; 89 int passwd_change_challenge_valid; 90 int passwd_change_version; 91 92 /* Optional challenge values generated in EAP-FAST Phase 1 negotiation 93 */ 94 u8 *peer_challenge; 95 u8 *auth_challenge; 96 97 int phase2; 98 u8 master_key[MSCHAPV2_MASTER_KEY_LEN]; 99 int master_key_valid; 100 int success; 101 102 struct wpabuf *prev_challenge; 103 }; 104 105 106 static void eap_mschapv2_deinit(struct eap_sm *sm, void *priv); 107 108 109 static void * eap_mschapv2_init(struct eap_sm *sm) 110 { 111 struct eap_mschapv2_data *data; 112 data = os_zalloc(sizeof(*data)); 113 if (data == NULL) 114 return NULL; 115 116 if (sm->peer_challenge) { 117 data->peer_challenge = os_malloc(MSCHAPV2_CHAL_LEN); 118 if (data->peer_challenge == NULL) { 119 eap_mschapv2_deinit(sm, data); 120 return NULL; 121 } 122 os_memcpy(data->peer_challenge, sm->peer_challenge, 123 MSCHAPV2_CHAL_LEN); 124 } 125 126 if (sm->auth_challenge) { 127 data->auth_challenge = os_malloc(MSCHAPV2_CHAL_LEN); 128 if (data->auth_challenge == NULL) { 129 eap_mschapv2_deinit(sm, data); 130 return NULL; 131 } 132 os_memcpy(data->auth_challenge, sm->auth_challenge, 133 MSCHAPV2_CHAL_LEN); 134 } 135 136 data->phase2 = sm->init_phase2; 137 138 return data; 139 } 140 141 142 static void eap_mschapv2_deinit(struct eap_sm *sm, void *priv) 143 { 144 struct eap_mschapv2_data *data = priv; 145 os_free(data->peer_challenge); 146 os_free(data->auth_challenge); 147 wpabuf_free(data->prev_challenge); 148 os_free(data); 149 } 150 151 152 static struct wpabuf * eap_mschapv2_challenge_reply( 153 struct eap_sm *sm, struct eap_mschapv2_data *data, u8 id, 154 u8 mschapv2_id, const u8 *auth_challenge) 155 { 156 struct wpabuf *resp; 157 struct eap_mschapv2_hdr *ms; 158 u8 *peer_challenge; 159 int ms_len; 160 struct ms_response *r; 161 size_t identity_len, password_len; 162 const u8 *identity, *password; 163 int pwhash; 164 165 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Generating Challenge Response"); 166 167 identity = eap_get_config_identity(sm, &identity_len); 168 password = eap_get_config_password2(sm, &password_len, &pwhash); 169 if (identity == NULL || password == NULL) 170 return NULL; 171 172 ms_len = sizeof(*ms) + 1 + sizeof(*r) + identity_len; 173 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, ms_len, 174 EAP_CODE_RESPONSE, id); 175 if (resp == NULL) 176 return NULL; 177 178 ms = wpabuf_put(resp, sizeof(*ms)); 179 ms->op_code = MSCHAPV2_OP_RESPONSE; 180 ms->mschapv2_id = mschapv2_id; 181 if (data->prev_error) { 182 /* 183 * TODO: this does not seem to be enough when processing two 184 * or more failure messages. IAS did not increment mschapv2_id 185 * in its own packets, but it seemed to expect the peer to 186 * increment this for all packets(?). 187 */ 188 ms->mschapv2_id++; 189 } 190 WPA_PUT_BE16(ms->ms_length, ms_len); 191 192 wpabuf_put_u8(resp, sizeof(*r)); /* Value-Size */ 193 194 /* Response */ 195 r = wpabuf_put(resp, sizeof(*r)); 196 peer_challenge = r->peer_challenge; 197 if (data->peer_challenge) { 198 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: peer_challenge generated " 199 "in Phase 1"); 200 peer_challenge = data->peer_challenge; 201 os_memset(r->peer_challenge, 0, MSCHAPV2_CHAL_LEN); 202 } else if (os_get_random(peer_challenge, MSCHAPV2_CHAL_LEN)) { 203 wpabuf_free(resp); 204 return NULL; 205 } 206 os_memset(r->reserved, 0, 8); 207 if (data->auth_challenge) { 208 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: auth_challenge generated " 209 "in Phase 1"); 210 auth_challenge = data->auth_challenge; 211 } 212 mschapv2_derive_response(identity, identity_len, password, 213 password_len, pwhash, auth_challenge, 214 peer_challenge, r->nt_response, 215 data->auth_response, data->master_key); 216 data->auth_response_valid = 1; 217 data->master_key_valid = 1; 218 219 r->flags = 0; /* reserved, must be zero */ 220 221 wpabuf_put_data(resp, identity, identity_len); 222 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: TX identifier %d mschapv2_id %d " 223 "(response)", id, ms->mschapv2_id); 224 return resp; 225 } 226 227 228 /** 229 * eap_mschapv2_process - Process an EAP-MSCHAPv2 challenge message 230 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 231 * @data: Pointer to private EAP method data from eap_mschapv2_init() 232 * @ret: Return values from EAP request validation and processing 233 * @req: Pointer to EAP-MSCHAPv2 header from the request 234 * @req_len: Length of the EAP-MSCHAPv2 data 235 * @id: EAP identifier used in the request 236 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 237 * no reply available 238 */ 239 static struct wpabuf * eap_mschapv2_challenge( 240 struct eap_sm *sm, struct eap_mschapv2_data *data, 241 struct eap_method_ret *ret, const struct eap_mschapv2_hdr *req, 242 size_t req_len, u8 id) 243 { 244 size_t len, challenge_len; 245 const u8 *pos, *challenge; 246 247 if (eap_get_config_identity(sm, &len) == NULL || 248 eap_get_config_password(sm, &len) == NULL) 249 return NULL; 250 251 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received challenge"); 252 if (req_len < sizeof(*req) + 1) { 253 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Too short challenge data " 254 "(len %lu)", (unsigned long) req_len); 255 ret->ignore = TRUE; 256 return NULL; 257 } 258 pos = (const u8 *) (req + 1); 259 challenge_len = *pos++; 260 len = req_len - sizeof(*req) - 1; 261 if (challenge_len != MSCHAPV2_CHAL_LEN) { 262 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Invalid challenge length " 263 "%lu", (unsigned long) challenge_len); 264 ret->ignore = TRUE; 265 return NULL; 266 } 267 268 if (len < challenge_len) { 269 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Too short challenge" 270 " packet: len=%lu challenge_len=%lu", 271 (unsigned long) len, (unsigned long) challenge_len); 272 ret->ignore = TRUE; 273 return NULL; 274 } 275 276 if (data->passwd_change_challenge_valid) { 277 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Using challenge from the " 278 "failure message"); 279 challenge = data->passwd_change_challenge; 280 } else 281 challenge = pos; 282 pos += challenge_len; 283 len -= challenge_len; 284 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Authentication Servername", 285 pos, len); 286 287 ret->ignore = FALSE; 288 ret->methodState = METHOD_MAY_CONT; 289 ret->decision = DECISION_FAIL; 290 ret->allowNotifications = TRUE; 291 292 return eap_mschapv2_challenge_reply(sm, data, id, req->mschapv2_id, 293 challenge); 294 } 295 296 297 static void eap_mschapv2_password_changed(struct eap_sm *sm, 298 struct eap_mschapv2_data *data) 299 { 300 struct eap_peer_config *config = eap_get_config(sm); 301 if (config && config->new_password) { 302 wpa_msg(sm->msg_ctx, MSG_INFO, 303 WPA_EVENT_PASSWORD_CHANGED 304 "EAP-MSCHAPV2: Password changed successfully"); 305 data->prev_error = 0; 306 os_free(config->password); 307 if (config->flags & EAP_CONFIG_FLAGS_PASSWORD_NTHASH) { 308 config->password = os_malloc(16); 309 config->password_len = 16; 310 if (config->password) { 311 nt_password_hash(config->new_password, 312 config->new_password_len, 313 config->password); 314 } 315 os_free(config->new_password); 316 } else { 317 config->password = config->new_password; 318 config->password_len = config->new_password_len; 319 } 320 config->new_password = NULL; 321 config->new_password_len = 0; 322 } 323 } 324 325 326 /** 327 * eap_mschapv2_process - Process an EAP-MSCHAPv2 success message 328 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 329 * @data: Pointer to private EAP method data from eap_mschapv2_init() 330 * @ret: Return values from EAP request validation and processing 331 * @req: Pointer to EAP-MSCHAPv2 header from the request 332 * @req_len: Length of the EAP-MSCHAPv2 data 333 * @id: EAP identifier used in th erequest 334 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 335 * no reply available 336 */ 337 static struct wpabuf * eap_mschapv2_success(struct eap_sm *sm, 338 struct eap_mschapv2_data *data, 339 struct eap_method_ret *ret, 340 const struct eap_mschapv2_hdr *req, 341 size_t req_len, u8 id) 342 { 343 struct wpabuf *resp; 344 const u8 *pos; 345 size_t len; 346 347 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received success"); 348 len = req_len - sizeof(*req); 349 pos = (const u8 *) (req + 1); 350 if (!data->auth_response_valid || 351 mschapv2_verify_auth_response(data->auth_response, pos, len)) { 352 wpa_printf(MSG_WARNING, "EAP-MSCHAPV2: Invalid authenticator " 353 "response in success request"); 354 ret->methodState = METHOD_DONE; 355 ret->decision = DECISION_FAIL; 356 return NULL; 357 } 358 pos += 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN; 359 len -= 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN; 360 while (len > 0 && *pos == ' ') { 361 pos++; 362 len--; 363 } 364 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Success message", 365 pos, len); 366 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Authentication succeeded"); 367 368 /* Note: Only op_code of the EAP-MSCHAPV2 header is included in success 369 * message. */ 370 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, 1, 371 EAP_CODE_RESPONSE, id); 372 if (resp == NULL) { 373 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Failed to allocate " 374 "buffer for success response"); 375 ret->ignore = TRUE; 376 return NULL; 377 } 378 379 wpabuf_put_u8(resp, MSCHAPV2_OP_SUCCESS); /* op_code */ 380 381 ret->methodState = METHOD_DONE; 382 ret->decision = DECISION_UNCOND_SUCC; 383 ret->allowNotifications = FALSE; 384 data->success = 1; 385 386 if (data->prev_error == ERROR_PASSWD_EXPIRED) 387 eap_mschapv2_password_changed(sm, data); 388 389 return resp; 390 } 391 392 393 static int eap_mschapv2_failure_txt(struct eap_sm *sm, 394 struct eap_mschapv2_data *data, char *txt) 395 { 396 char *pos, *msg = ""; 397 int retry = 1; 398 struct eap_peer_config *config = eap_get_config(sm); 399 400 /* For example: 401 * E=691 R=1 C=<32 octets hex challenge> V=3 M=Authentication Failure 402 */ 403 404 pos = txt; 405 406 if (pos && os_strncmp(pos, "E=", 2) == 0) { 407 pos += 2; 408 data->prev_error = atoi(pos); 409 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: error %d", 410 data->prev_error); 411 pos = os_strchr(pos, ' '); 412 if (pos) 413 pos++; 414 } 415 416 if (pos && os_strncmp(pos, "R=", 2) == 0) { 417 pos += 2; 418 retry = atoi(pos); 419 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: retry is %sallowed", 420 retry == 1 ? "" : "not "); 421 pos = os_strchr(pos, ' '); 422 if (pos) 423 pos++; 424 } 425 426 if (pos && os_strncmp(pos, "C=", 2) == 0) { 427 int hex_len; 428 pos += 2; 429 hex_len = os_strchr(pos, ' ') - (char *) pos; 430 if (hex_len == PASSWD_CHANGE_CHAL_LEN * 2) { 431 if (hexstr2bin(pos, data->passwd_change_challenge, 432 PASSWD_CHANGE_CHAL_LEN)) { 433 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: invalid " 434 "failure challenge"); 435 } else { 436 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: failure " 437 "challenge", 438 data->passwd_change_challenge, 439 PASSWD_CHANGE_CHAL_LEN); 440 data->passwd_change_challenge_valid = 1; 441 } 442 } else { 443 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: invalid failure " 444 "challenge len %d", hex_len); 445 } 446 pos = os_strchr(pos, ' '); 447 if (pos) 448 pos++; 449 } else { 450 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: required challenge field " 451 "was not present in failure message"); 452 } 453 454 if (pos && os_strncmp(pos, "V=", 2) == 0) { 455 pos += 2; 456 data->passwd_change_version = atoi(pos); 457 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: password changing " 458 "protocol version %d", data->passwd_change_version); 459 pos = os_strchr(pos, ' '); 460 if (pos) 461 pos++; 462 } 463 464 if (pos && os_strncmp(pos, "M=", 2) == 0) { 465 pos += 2; 466 msg = pos; 467 } 468 wpa_msg(sm->msg_ctx, MSG_WARNING, 469 "EAP-MSCHAPV2: failure message: '%s' (retry %sallowed, error " 470 "%d)", 471 msg, retry == 1 ? "" : "not ", data->prev_error); 472 if (data->prev_error == ERROR_PASSWD_EXPIRED && 473 data->passwd_change_version == 3 && config) { 474 if (config->new_password == NULL) { 475 wpa_msg(sm->msg_ctx, MSG_INFO, 476 "EAP-MSCHAPV2: Password expired - password " 477 "change required"); 478 eap_sm_request_new_password(sm); 479 } 480 } else if (retry == 1 && config) { 481 /* TODO: could prevent the current password from being used 482 * again at least for some period of time */ 483 if (!config->mschapv2_retry) 484 eap_sm_request_identity(sm); 485 eap_sm_request_password(sm); 486 config->mschapv2_retry = 1; 487 } else if (config) { 488 /* TODO: prevent retries using same username/password */ 489 config->mschapv2_retry = 0; 490 } 491 492 return retry == 1; 493 } 494 495 496 static struct wpabuf * eap_mschapv2_change_password( 497 struct eap_sm *sm, struct eap_mschapv2_data *data, 498 struct eap_method_ret *ret, const struct eap_mschapv2_hdr *req, u8 id) 499 { 500 struct wpabuf *resp; 501 int ms_len; 502 const u8 *username, *password, *new_password; 503 size_t username_len, password_len, new_password_len; 504 struct eap_mschapv2_hdr *ms; 505 struct ms_change_password *cp; 506 u8 password_hash[16], password_hash_hash[16]; 507 int pwhash; 508 509 username = eap_get_config_identity(sm, &username_len); 510 password = eap_get_config_password2(sm, &password_len, &pwhash); 511 new_password = eap_get_config_new_password(sm, &new_password_len); 512 if (username == NULL || password == NULL || new_password == NULL) 513 return NULL; 514 515 username = mschapv2_remove_domain(username, &username_len); 516 517 ret->ignore = FALSE; 518 ret->methodState = METHOD_MAY_CONT; 519 ret->decision = DECISION_COND_SUCC; 520 ret->allowNotifications = TRUE; 521 522 ms_len = sizeof(*ms) + sizeof(*cp); 523 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, ms_len, 524 EAP_CODE_RESPONSE, id); 525 if (resp == NULL) 526 return NULL; 527 528 ms = wpabuf_put(resp, sizeof(*ms)); 529 ms->op_code = MSCHAPV2_OP_CHANGE_PASSWORD; 530 ms->mschapv2_id = req->mschapv2_id + 1; 531 WPA_PUT_BE16(ms->ms_length, ms_len); 532 cp = wpabuf_put(resp, sizeof(*cp)); 533 534 /* Encrypted-Password */ 535 if (pwhash) { 536 if (encrypt_pw_block_with_password_hash( 537 new_password, new_password_len, 538 password, cp->encr_password)) 539 goto fail; 540 } else { 541 if (new_password_encrypted_with_old_nt_password_hash( 542 new_password, new_password_len, 543 password, password_len, cp->encr_password)) 544 goto fail; 545 } 546 547 /* Encrypted-Hash */ 548 if (pwhash) { 549 u8 new_password_hash[16]; 550 nt_password_hash(new_password, new_password_len, 551 new_password_hash); 552 nt_password_hash_encrypted_with_block(password, 553 new_password_hash, 554 cp->encr_hash); 555 } else { 556 old_nt_password_hash_encrypted_with_new_nt_password_hash( 557 new_password, new_password_len, 558 password, password_len, cp->encr_hash); 559 } 560 561 /* Peer-Challenge */ 562 if (os_get_random(cp->peer_challenge, MSCHAPV2_CHAL_LEN)) 563 goto fail; 564 565 /* Reserved, must be zero */ 566 os_memset(cp->reserved, 0, 8); 567 568 /* NT-Response */ 569 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: auth_challenge", 570 data->passwd_change_challenge, PASSWD_CHANGE_CHAL_LEN); 571 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: peer_challenge", 572 cp->peer_challenge, MSCHAPV2_CHAL_LEN); 573 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: username", 574 username, username_len); 575 wpa_hexdump_ascii_key(MSG_DEBUG, "EAP-MSCHAPV2: new password", 576 new_password, new_password_len); 577 generate_nt_response(data->passwd_change_challenge, cp->peer_challenge, 578 username, username_len, 579 new_password, new_password_len, 580 cp->nt_response); 581 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: NT-Response", 582 cp->nt_response, MSCHAPV2_NT_RESPONSE_LEN); 583 584 /* Authenticator response is not really needed yet, but calculate it 585 * here so that challenges need not be saved. */ 586 generate_authenticator_response(new_password, new_password_len, 587 cp->peer_challenge, 588 data->passwd_change_challenge, 589 username, username_len, 590 cp->nt_response, data->auth_response); 591 data->auth_response_valid = 1; 592 593 /* Likewise, generate master_key here since we have the needed data 594 * available. */ 595 nt_password_hash(new_password, new_password_len, password_hash); 596 hash_nt_password_hash(password_hash, password_hash_hash); 597 get_master_key(password_hash_hash, cp->nt_response, data->master_key); 598 data->master_key_valid = 1; 599 600 /* Flags */ 601 os_memset(cp->flags, 0, 2); 602 603 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: TX identifier %d mschapv2_id %d " 604 "(change pw)", id, ms->mschapv2_id); 605 606 return resp; 607 608 fail: 609 wpabuf_free(resp); 610 return NULL; 611 } 612 613 614 /** 615 * eap_mschapv2_process - Process an EAP-MSCHAPv2 failure message 616 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 617 * @data: Pointer to private EAP method data from eap_mschapv2_init() 618 * @ret: Return values from EAP request validation and processing 619 * @req: Pointer to EAP-MSCHAPv2 header from the request 620 * @req_len: Length of the EAP-MSCHAPv2 data 621 * @id: EAP identifier used in th erequest 622 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 623 * no reply available 624 */ 625 static struct wpabuf * eap_mschapv2_failure(struct eap_sm *sm, 626 struct eap_mschapv2_data *data, 627 struct eap_method_ret *ret, 628 const struct eap_mschapv2_hdr *req, 629 size_t req_len, u8 id) 630 { 631 struct wpabuf *resp; 632 const u8 *msdata = (const u8 *) (req + 1); 633 char *buf; 634 size_t len = req_len - sizeof(*req); 635 int retry = 0; 636 637 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received failure"); 638 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Failure data", 639 msdata, len); 640 /* 641 * eap_mschapv2_failure_txt() expects a nul terminated string, so we 642 * must allocate a large enough temporary buffer to create that since 643 * the received message does not include nul termination. 644 */ 645 buf = os_malloc(len + 1); 646 if (buf) { 647 os_memcpy(buf, msdata, len); 648 buf[len] = '\0'; 649 retry = eap_mschapv2_failure_txt(sm, data, buf); 650 os_free(buf); 651 } 652 653 ret->ignore = FALSE; 654 ret->methodState = METHOD_DONE; 655 ret->decision = DECISION_FAIL; 656 ret->allowNotifications = FALSE; 657 658 if (data->prev_error == ERROR_PASSWD_EXPIRED && 659 data->passwd_change_version == 3) { 660 struct eap_peer_config *config = eap_get_config(sm); 661 if (config && config->new_password) 662 return eap_mschapv2_change_password(sm, data, ret, req, 663 id); 664 if (config && config->pending_req_new_password) 665 return NULL; 666 } else if (retry && data->prev_error == ERROR_AUTHENTICATION_FAILURE) { 667 /* TODO: could try to retry authentication, e.g, after having 668 * changed the username/password. In this case, EAP MS-CHAP-v2 669 * Failure Response would not be sent here. */ 670 return NULL; 671 } 672 673 /* Note: Only op_code of the EAP-MSCHAPV2 header is included in failure 674 * message. */ 675 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, 1, 676 EAP_CODE_RESPONSE, id); 677 if (resp == NULL) 678 return NULL; 679 680 wpabuf_put_u8(resp, MSCHAPV2_OP_FAILURE); /* op_code */ 681 682 return resp; 683 } 684 685 686 static int eap_mschapv2_check_config(struct eap_sm *sm) 687 { 688 size_t len; 689 690 if (eap_get_config_identity(sm, &len) == NULL) { 691 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Identity not configured"); 692 eap_sm_request_identity(sm); 693 return -1; 694 } 695 696 if (eap_get_config_password(sm, &len) == NULL) { 697 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Password not configured"); 698 eap_sm_request_password(sm); 699 return -1; 700 } 701 702 return 0; 703 } 704 705 706 static int eap_mschapv2_check_mslen(struct eap_sm *sm, size_t len, 707 const struct eap_mschapv2_hdr *ms) 708 { 709 size_t ms_len = WPA_GET_BE16(ms->ms_length); 710 711 if (ms_len == len) 712 return 0; 713 714 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Invalid header: len=%lu " 715 "ms_len=%lu", (unsigned long) len, (unsigned long) ms_len); 716 if (sm->workaround) { 717 /* Some authentication servers use invalid ms_len, 718 * ignore it for interoperability. */ 719 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: workaround, ignore" 720 " invalid ms_len %lu (len %lu)", 721 (unsigned long) ms_len, 722 (unsigned long) len); 723 return 0; 724 } 725 726 return -1; 727 } 728 729 730 static void eap_mschapv2_copy_challenge(struct eap_mschapv2_data *data, 731 const struct wpabuf *reqData) 732 { 733 /* 734 * Store a copy of the challenge message, so that it can be processed 735 * again in case retry is allowed after a possible failure. 736 */ 737 wpabuf_free(data->prev_challenge); 738 data->prev_challenge = wpabuf_dup(reqData); 739 } 740 741 742 /** 743 * eap_mschapv2_process - Process an EAP-MSCHAPv2 request 744 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 745 * @priv: Pointer to private EAP method data from eap_mschapv2_init() 746 * @ret: Return values from EAP request validation and processing 747 * @reqData: EAP request to be processed (eapReqData) 748 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 749 * no reply available 750 */ 751 static struct wpabuf * eap_mschapv2_process(struct eap_sm *sm, void *priv, 752 struct eap_method_ret *ret, 753 const struct wpabuf *reqData) 754 { 755 struct eap_mschapv2_data *data = priv; 756 struct eap_peer_config *config = eap_get_config(sm); 757 const struct eap_mschapv2_hdr *ms; 758 int using_prev_challenge = 0; 759 const u8 *pos; 760 size_t len; 761 u8 id; 762 763 if (eap_mschapv2_check_config(sm)) { 764 ret->ignore = TRUE; 765 return NULL; 766 } 767 768 if (config->mschapv2_retry && data->prev_challenge && 769 data->prev_error == ERROR_AUTHENTICATION_FAILURE) { 770 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Replacing pending packet " 771 "with the previous challenge"); 772 773 reqData = data->prev_challenge; 774 using_prev_challenge = 1; 775 config->mschapv2_retry = 0; 776 } 777 778 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, reqData, 779 &len); 780 if (pos == NULL || len < sizeof(*ms) + 1) { 781 ret->ignore = TRUE; 782 return NULL; 783 } 784 785 ms = (const struct eap_mschapv2_hdr *) pos; 786 if (eap_mschapv2_check_mslen(sm, len, ms)) { 787 ret->ignore = TRUE; 788 return NULL; 789 } 790 791 id = eap_get_id(reqData); 792 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: RX identifier %d mschapv2_id %d", 793 id, ms->mschapv2_id); 794 795 switch (ms->op_code) { 796 case MSCHAPV2_OP_CHALLENGE: 797 if (!using_prev_challenge) 798 eap_mschapv2_copy_challenge(data, reqData); 799 return eap_mschapv2_challenge(sm, data, ret, ms, len, id); 800 case MSCHAPV2_OP_SUCCESS: 801 return eap_mschapv2_success(sm, data, ret, ms, len, id); 802 case MSCHAPV2_OP_FAILURE: 803 return eap_mschapv2_failure(sm, data, ret, ms, len, id); 804 default: 805 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Unknown op %d - ignored", 806 ms->op_code); 807 ret->ignore = TRUE; 808 return NULL; 809 } 810 } 811 812 813 static Boolean eap_mschapv2_isKeyAvailable(struct eap_sm *sm, void *priv) 814 { 815 struct eap_mschapv2_data *data = priv; 816 return data->success && data->master_key_valid; 817 } 818 819 820 static u8 * eap_mschapv2_getKey(struct eap_sm *sm, void *priv, size_t *len) 821 { 822 struct eap_mschapv2_data *data = priv; 823 u8 *key; 824 int key_len; 825 826 if (!data->master_key_valid || !data->success) 827 return NULL; 828 829 key_len = 2 * MSCHAPV2_KEY_LEN; 830 831 key = os_malloc(key_len); 832 if (key == NULL) 833 return NULL; 834 835 /* MSK = server MS-MPPE-Recv-Key | MS-MPPE-Send-Key, i.e., 836 * peer MS-MPPE-Send-Key | MS-MPPE-Recv-Key */ 837 get_asymetric_start_key(data->master_key, key, MSCHAPV2_KEY_LEN, 1, 0); 838 get_asymetric_start_key(data->master_key, key + MSCHAPV2_KEY_LEN, 839 MSCHAPV2_KEY_LEN, 0, 0); 840 841 wpa_hexdump_key(MSG_DEBUG, "EAP-MSCHAPV2: Derived key", 842 key, key_len); 843 844 *len = key_len; 845 return key; 846 } 847 848 849 /** 850 * eap_peer_mschapv2_register - Register EAP-MSCHAPv2 peer method 851 * Returns: 0 on success, -1 on failure 852 * 853 * This function is used to register EAP-MSCHAPv2 peer method into the EAP 854 * method list. 855 */ 856 int eap_peer_mschapv2_register(void) 857 { 858 struct eap_method *eap; 859 int ret; 860 861 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION, 862 EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, 863 "MSCHAPV2"); 864 if (eap == NULL) 865 return -1; 866 867 eap->init = eap_mschapv2_init; 868 eap->deinit = eap_mschapv2_deinit; 869 eap->process = eap_mschapv2_process; 870 eap->isKeyAvailable = eap_mschapv2_isKeyAvailable; 871 eap->getKey = eap_mschapv2_getKey; 872 873 ret = eap_peer_method_register(eap); 874 if (ret) 875 eap_peer_method_free(eap); 876 return ret; 877 } 878
