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 software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 * 8 * This file implements EAP peer part of EAP-MSCHAPV2 method (EAP type 26). 9 * draft-kamath-pppext-eap-mschapv2-00.txt defines the Microsoft EAP CHAP 10 * Extensions Protocol, Version 2, for mutual authentication and key 11 * derivation. This encapsulates MS-CHAP-v2 protocol which is defined in 12 * RFC 2759. Use of EAP-MSCHAPV2 derived keys with MPPE cipher is described in 13 * RFC 3079. 14 */ 15 16 #include "includes.h" 17 18 #include "common.h" 19 #include "crypto/ms_funcs.h" 20 #include "crypto/random.h" 21 #include "common/wpa_ctrl.h" 22 #include "mschapv2.h" 23 #include "eap_i.h" 24 #include "eap_config.h" 25 26 27 #ifdef _MSC_VER 28 #pragma pack(push, 1) 29 #endif /* _MSC_VER */ 30 31 struct eap_mschapv2_hdr { 32 u8 op_code; /* MSCHAPV2_OP_* */ 33 u8 mschapv2_id; /* usually same as EAP identifier; must be changed 34 * for challenges, but not for success/failure */ 35 u8 ms_length[2]; /* Note: misaligned; length - 5 */ 36 /* followed by data */ 37 } STRUCT_PACKED; 38 39 /* Response Data field */ 40 struct ms_response { 41 u8 peer_challenge[MSCHAPV2_CHAL_LEN]; 42 u8 reserved[8]; 43 u8 nt_response[MSCHAPV2_NT_RESPONSE_LEN]; 44 u8 flags; 45 } STRUCT_PACKED; 46 47 /* Change-Password Data field */ 48 struct ms_change_password { 49 u8 encr_password[516]; 50 u8 encr_hash[16]; 51 u8 peer_challenge[MSCHAPV2_CHAL_LEN]; 52 u8 reserved[8]; 53 u8 nt_response[MSCHAPV2_NT_RESPONSE_LEN]; 54 u8 flags[2]; 55 } STRUCT_PACKED; 56 57 #ifdef _MSC_VER 58 #pragma pack(pop) 59 #endif /* _MSC_VER */ 60 61 #define MSCHAPV2_OP_CHALLENGE 1 62 #define MSCHAPV2_OP_RESPONSE 2 63 #define MSCHAPV2_OP_SUCCESS 3 64 #define MSCHAPV2_OP_FAILURE 4 65 #define MSCHAPV2_OP_CHANGE_PASSWORD 7 66 67 #define ERROR_RESTRICTED_LOGON_HOURS 646 68 #define ERROR_ACCT_DISABLED 647 69 #define ERROR_PASSWD_EXPIRED 648 70 #define ERROR_NO_DIALIN_PERMISSION 649 71 #define ERROR_AUTHENTICATION_FAILURE 691 72 #define ERROR_CHANGING_PASSWORD 709 73 74 #define PASSWD_CHANGE_CHAL_LEN 16 75 #define MSCHAPV2_KEY_LEN 16 76 77 78 struct eap_mschapv2_data { 79 u8 auth_response[MSCHAPV2_AUTH_RESPONSE_LEN]; 80 int auth_response_valid; 81 82 int prev_error; 83 u8 passwd_change_challenge[PASSWD_CHANGE_CHAL_LEN]; 84 int passwd_change_challenge_valid; 85 int passwd_change_version; 86 87 /* Optional challenge values generated in EAP-FAST Phase 1 negotiation 88 */ 89 u8 *peer_challenge; 90 u8 *auth_challenge; 91 92 int phase2; 93 u8 master_key[MSCHAPV2_MASTER_KEY_LEN]; 94 int master_key_valid; 95 int success; 96 97 struct wpabuf *prev_challenge; 98 }; 99 100 101 static void eap_mschapv2_deinit(struct eap_sm *sm, void *priv); 102 103 104 static void * eap_mschapv2_init(struct eap_sm *sm) 105 { 106 struct eap_mschapv2_data *data; 107 data = os_zalloc(sizeof(*data)); 108 if (data == NULL) 109 return NULL; 110 111 if (sm->peer_challenge) { 112 data->peer_challenge = os_malloc(MSCHAPV2_CHAL_LEN); 113 if (data->peer_challenge == NULL) { 114 eap_mschapv2_deinit(sm, data); 115 return NULL; 116 } 117 os_memcpy(data->peer_challenge, sm->peer_challenge, 118 MSCHAPV2_CHAL_LEN); 119 } 120 121 if (sm->auth_challenge) { 122 data->auth_challenge = os_malloc(MSCHAPV2_CHAL_LEN); 123 if (data->auth_challenge == NULL) { 124 eap_mschapv2_deinit(sm, data); 125 return NULL; 126 } 127 os_memcpy(data->auth_challenge, sm->auth_challenge, 128 MSCHAPV2_CHAL_LEN); 129 } 130 131 data->phase2 = sm->init_phase2; 132 133 return data; 134 } 135 136 137 static void eap_mschapv2_deinit(struct eap_sm *sm, void *priv) 138 { 139 struct eap_mschapv2_data *data = priv; 140 os_free(data->peer_challenge); 141 os_free(data->auth_challenge); 142 wpabuf_free(data->prev_challenge); 143 os_free(data); 144 } 145 146 147 static struct wpabuf * eap_mschapv2_challenge_reply( 148 struct eap_sm *sm, struct eap_mschapv2_data *data, u8 id, 149 u8 mschapv2_id, const u8 *auth_challenge) 150 { 151 struct wpabuf *resp; 152 struct eap_mschapv2_hdr *ms; 153 u8 *peer_challenge; 154 int ms_len; 155 struct ms_response *r; 156 size_t identity_len, password_len; 157 const u8 *identity, *password; 158 int pwhash; 159 160 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Generating Challenge Response"); 161 162 identity = eap_get_config_identity(sm, &identity_len); 163 password = eap_get_config_password2(sm, &password_len, &pwhash); 164 if (identity == NULL || password == NULL) 165 return NULL; 166 167 ms_len = sizeof(*ms) + 1 + sizeof(*r) + identity_len; 168 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, ms_len, 169 EAP_CODE_RESPONSE, id); 170 if (resp == NULL) 171 return NULL; 172 173 ms = wpabuf_put(resp, sizeof(*ms)); 174 ms->op_code = MSCHAPV2_OP_RESPONSE; 175 ms->mschapv2_id = mschapv2_id; 176 if (data->prev_error) { 177 /* 178 * TODO: this does not seem to be enough when processing two 179 * or more failure messages. IAS did not increment mschapv2_id 180 * in its own packets, but it seemed to expect the peer to 181 * increment this for all packets(?). 182 */ 183 ms->mschapv2_id++; 184 } 185 WPA_PUT_BE16(ms->ms_length, ms_len); 186 187 wpabuf_put_u8(resp, sizeof(*r)); /* Value-Size */ 188 189 /* Response */ 190 r = wpabuf_put(resp, sizeof(*r)); 191 peer_challenge = r->peer_challenge; 192 if (data->peer_challenge) { 193 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: peer_challenge generated " 194 "in Phase 1"); 195 peer_challenge = data->peer_challenge; 196 os_memset(r->peer_challenge, 0, MSCHAPV2_CHAL_LEN); 197 } else if (random_get_bytes(peer_challenge, MSCHAPV2_CHAL_LEN)) { 198 wpabuf_free(resp); 199 return NULL; 200 } 201 os_memset(r->reserved, 0, 8); 202 if (data->auth_challenge) { 203 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: auth_challenge generated " 204 "in Phase 1"); 205 auth_challenge = data->auth_challenge; 206 } 207 if (mschapv2_derive_response(identity, identity_len, password, 208 password_len, pwhash, auth_challenge, 209 peer_challenge, r->nt_response, 210 data->auth_response, data->master_key)) { 211 wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to derive " 212 "response"); 213 wpabuf_free(resp); 214 return NULL; 215 } 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_EXT_PASSWORD) { 308 /* TODO: update external storage */ 309 } else if (config->flags & EAP_CONFIG_FLAGS_PASSWORD_NTHASH) { 310 config->password = os_malloc(16); 311 config->password_len = 16; 312 if (config->password) { 313 nt_password_hash(config->new_password, 314 config->new_password_len, 315 config->password); 316 } 317 os_free(config->new_password); 318 } else { 319 config->password = config->new_password; 320 config->password_len = config->new_password_len; 321 } 322 config->new_password = NULL; 323 config->new_password_len = 0; 324 } 325 } 326 327 328 /** 329 * eap_mschapv2_process - Process an EAP-MSCHAPv2 success message 330 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 331 * @data: Pointer to private EAP method data from eap_mschapv2_init() 332 * @ret: Return values from EAP request validation and processing 333 * @req: Pointer to EAP-MSCHAPv2 header from the request 334 * @req_len: Length of the EAP-MSCHAPv2 data 335 * @id: EAP identifier used in th erequest 336 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 337 * no reply available 338 */ 339 static struct wpabuf * eap_mschapv2_success(struct eap_sm *sm, 340 struct eap_mschapv2_data *data, 341 struct eap_method_ret *ret, 342 const struct eap_mschapv2_hdr *req, 343 size_t req_len, u8 id) 344 { 345 struct wpabuf *resp; 346 const u8 *pos; 347 size_t len; 348 349 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received success"); 350 len = req_len - sizeof(*req); 351 pos = (const u8 *) (req + 1); 352 if (!data->auth_response_valid || 353 mschapv2_verify_auth_response(data->auth_response, pos, len)) { 354 wpa_printf(MSG_WARNING, "EAP-MSCHAPV2: Invalid authenticator " 355 "response in success request"); 356 ret->methodState = METHOD_DONE; 357 ret->decision = DECISION_FAIL; 358 return NULL; 359 } 360 pos += 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN; 361 len -= 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN; 362 while (len > 0 && *pos == ' ') { 363 pos++; 364 len--; 365 } 366 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Success message", 367 pos, len); 368 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Authentication succeeded"); 369 370 /* Note: Only op_code of the EAP-MSCHAPV2 header is included in success 371 * message. */ 372 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, 1, 373 EAP_CODE_RESPONSE, id); 374 if (resp == NULL) { 375 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Failed to allocate " 376 "buffer for success response"); 377 ret->ignore = TRUE; 378 return NULL; 379 } 380 381 wpabuf_put_u8(resp, MSCHAPV2_OP_SUCCESS); /* op_code */ 382 383 ret->methodState = METHOD_DONE; 384 ret->decision = DECISION_UNCOND_SUCC; 385 ret->allowNotifications = FALSE; 386 data->success = 1; 387 388 if (data->prev_error == ERROR_PASSWD_EXPIRED) 389 eap_mschapv2_password_changed(sm, data); 390 391 return resp; 392 } 393 394 395 static int eap_mschapv2_failure_txt(struct eap_sm *sm, 396 struct eap_mschapv2_data *data, char *txt) 397 { 398 char *pos, *msg = ""; 399 int retry = 1; 400 struct eap_peer_config *config = eap_get_config(sm); 401 402 /* For example: 403 * E=691 R=1 C=<32 octets hex challenge> V=3 M=Authentication Failure 404 */ 405 406 pos = txt; 407 408 if (pos && os_strncmp(pos, "E=", 2) == 0) { 409 pos += 2; 410 data->prev_error = atoi(pos); 411 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: error %d", 412 data->prev_error); 413 pos = os_strchr(pos, ' '); 414 if (pos) 415 pos++; 416 } 417 418 if (pos && os_strncmp(pos, "R=", 2) == 0) { 419 pos += 2; 420 retry = atoi(pos); 421 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: retry is %sallowed", 422 retry == 1 ? "" : "not "); 423 pos = os_strchr(pos, ' '); 424 if (pos) 425 pos++; 426 } 427 428 if (pos && os_strncmp(pos, "C=", 2) == 0) { 429 int hex_len; 430 pos += 2; 431 hex_len = os_strchr(pos, ' ') - (char *) pos; 432 if (hex_len == PASSWD_CHANGE_CHAL_LEN * 2) { 433 if (hexstr2bin(pos, data->passwd_change_challenge, 434 PASSWD_CHANGE_CHAL_LEN)) { 435 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: invalid " 436 "failure challenge"); 437 } else { 438 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: failure " 439 "challenge", 440 data->passwd_change_challenge, 441 PASSWD_CHANGE_CHAL_LEN); 442 data->passwd_change_challenge_valid = 1; 443 } 444 } else { 445 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: invalid failure " 446 "challenge len %d", hex_len); 447 } 448 pos = os_strchr(pos, ' '); 449 if (pos) 450 pos++; 451 } else { 452 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: required challenge field " 453 "was not present in failure message"); 454 } 455 456 if (pos && os_strncmp(pos, "V=", 2) == 0) { 457 pos += 2; 458 data->passwd_change_version = atoi(pos); 459 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: password changing " 460 "protocol version %d", data->passwd_change_version); 461 pos = os_strchr(pos, ' '); 462 if (pos) 463 pos++; 464 } 465 466 if (pos && os_strncmp(pos, "M=", 2) == 0) { 467 pos += 2; 468 msg = pos; 469 } 470 wpa_msg(sm->msg_ctx, MSG_WARNING, 471 "EAP-MSCHAPV2: failure message: '%s' (retry %sallowed, error " 472 "%d)", 473 msg, retry == 1 ? "" : "not ", data->prev_error); 474 if (data->prev_error == ERROR_PASSWD_EXPIRED && 475 data->passwd_change_version == 3 && config) { 476 if (config->new_password == NULL) { 477 wpa_msg(sm->msg_ctx, MSG_INFO, 478 "EAP-MSCHAPV2: Password expired - password " 479 "change required"); 480 eap_sm_request_new_password(sm); 481 } 482 } else if (retry == 1 && config) { 483 /* TODO: could prevent the current password from being used 484 * again at least for some period of time */ 485 if (!config->mschapv2_retry) 486 eap_sm_request_identity(sm); 487 eap_sm_request_password(sm); 488 config->mschapv2_retry = 1; 489 } else if (config) { 490 /* TODO: prevent retries using same username/password */ 491 config->mschapv2_retry = 0; 492 } 493 494 return retry == 1; 495 } 496 497 498 static struct wpabuf * eap_mschapv2_change_password( 499 struct eap_sm *sm, struct eap_mschapv2_data *data, 500 struct eap_method_ret *ret, const struct eap_mschapv2_hdr *req, u8 id) 501 { 502 struct wpabuf *resp; 503 int ms_len; 504 const u8 *username, *password, *new_password; 505 size_t username_len, password_len, new_password_len; 506 struct eap_mschapv2_hdr *ms; 507 struct ms_change_password *cp; 508 u8 password_hash[16], password_hash_hash[16]; 509 int pwhash; 510 511 username = eap_get_config_identity(sm, &username_len); 512 password = eap_get_config_password2(sm, &password_len, &pwhash); 513 new_password = eap_get_config_new_password(sm, &new_password_len); 514 if (username == NULL || password == NULL || new_password == NULL) 515 return NULL; 516 517 username = mschapv2_remove_domain(username, &username_len); 518 519 ret->ignore = FALSE; 520 ret->methodState = METHOD_MAY_CONT; 521 ret->decision = DECISION_COND_SUCC; 522 ret->allowNotifications = TRUE; 523 524 ms_len = sizeof(*ms) + sizeof(*cp); 525 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, ms_len, 526 EAP_CODE_RESPONSE, id); 527 if (resp == NULL) 528 return NULL; 529 530 ms = wpabuf_put(resp, sizeof(*ms)); 531 ms->op_code = MSCHAPV2_OP_CHANGE_PASSWORD; 532 ms->mschapv2_id = req->mschapv2_id + 1; 533 WPA_PUT_BE16(ms->ms_length, ms_len); 534 cp = wpabuf_put(resp, sizeof(*cp)); 535 536 /* Encrypted-Password */ 537 if (pwhash) { 538 if (encrypt_pw_block_with_password_hash( 539 new_password, new_password_len, 540 password, cp->encr_password)) 541 goto fail; 542 } else { 543 if (new_password_encrypted_with_old_nt_password_hash( 544 new_password, new_password_len, 545 password, password_len, cp->encr_password)) 546 goto fail; 547 } 548 549 /* Encrypted-Hash */ 550 if (pwhash) { 551 u8 new_password_hash[16]; 552 nt_password_hash(new_password, new_password_len, 553 new_password_hash); 554 nt_password_hash_encrypted_with_block(password, 555 new_password_hash, 556 cp->encr_hash); 557 } else { 558 old_nt_password_hash_encrypted_with_new_nt_password_hash( 559 new_password, new_password_len, 560 password, password_len, cp->encr_hash); 561 } 562 563 /* Peer-Challenge */ 564 if (random_get_bytes(cp->peer_challenge, MSCHAPV2_CHAL_LEN)) 565 goto fail; 566 567 /* Reserved, must be zero */ 568 os_memset(cp->reserved, 0, 8); 569 570 /* NT-Response */ 571 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: auth_challenge", 572 data->passwd_change_challenge, PASSWD_CHANGE_CHAL_LEN); 573 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: peer_challenge", 574 cp->peer_challenge, MSCHAPV2_CHAL_LEN); 575 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: username", 576 username, username_len); 577 wpa_hexdump_ascii_key(MSG_DEBUG, "EAP-MSCHAPV2: new password", 578 new_password, new_password_len); 579 generate_nt_response(data->passwd_change_challenge, cp->peer_challenge, 580 username, username_len, 581 new_password, new_password_len, 582 cp->nt_response); 583 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: NT-Response", 584 cp->nt_response, MSCHAPV2_NT_RESPONSE_LEN); 585 586 /* Authenticator response is not really needed yet, but calculate it 587 * here so that challenges need not be saved. */ 588 generate_authenticator_response(new_password, new_password_len, 589 cp->peer_challenge, 590 data->passwd_change_challenge, 591 username, username_len, 592 cp->nt_response, data->auth_response); 593 data->auth_response_valid = 1; 594 595 /* Likewise, generate master_key here since we have the needed data 596 * available. */ 597 nt_password_hash(new_password, new_password_len, password_hash); 598 hash_nt_password_hash(password_hash, password_hash_hash); 599 get_master_key(password_hash_hash, cp->nt_response, data->master_key); 600 data->master_key_valid = 1; 601 602 /* Flags */ 603 os_memset(cp->flags, 0, 2); 604 605 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: TX identifier %d mschapv2_id %d " 606 "(change pw)", id, ms->mschapv2_id); 607 608 return resp; 609 610 fail: 611 wpabuf_free(resp); 612 return NULL; 613 } 614 615 616 /** 617 * eap_mschapv2_process - Process an EAP-MSCHAPv2 failure message 618 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 619 * @data: Pointer to private EAP method data from eap_mschapv2_init() 620 * @ret: Return values from EAP request validation and processing 621 * @req: Pointer to EAP-MSCHAPv2 header from the request 622 * @req_len: Length of the EAP-MSCHAPv2 data 623 * @id: EAP identifier used in th erequest 624 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 625 * no reply available 626 */ 627 static struct wpabuf * eap_mschapv2_failure(struct eap_sm *sm, 628 struct eap_mschapv2_data *data, 629 struct eap_method_ret *ret, 630 const struct eap_mschapv2_hdr *req, 631 size_t req_len, u8 id) 632 { 633 struct wpabuf *resp; 634 const u8 *msdata = (const u8 *) (req + 1); 635 char *buf; 636 size_t len = req_len - sizeof(*req); 637 int retry = 0; 638 639 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received failure"); 640 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Failure data", 641 msdata, len); 642 /* 643 * eap_mschapv2_failure_txt() expects a nul terminated string, so we 644 * must allocate a large enough temporary buffer to create that since 645 * the received message does not include nul termination. 646 */ 647 buf = dup_binstr(msdata, len); 648 if (buf) { 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
