eap_mschapv2.c revision 43cb578dfe2c492257636f6234a24178ed27789e
1/* 2 * EAP peer method: EAP-MSCHAPV2 (draft-kamath-pppext-eap-mschapv2-00.txt) 3 * Copyright (c) 2004-2008, 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 * 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 31struct 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 */ 40struct 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 */ 48struct 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 78struct 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 101static void eap_mschapv2_deinit(struct eap_sm *sm, void *priv); 102 103 104static 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 137static 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 147static 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 */ 239static 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 297static 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 os_free(config->password); 317 config->password = NULL; 318 config->password_len = 0; 319 } 320 os_free(config->new_password); 321 } else { 322 config->password = config->new_password; 323 config->password_len = config->new_password_len; 324 } 325 config->new_password = NULL; 326 config->new_password_len = 0; 327 } 328} 329 330 331/** 332 * eap_mschapv2_process - Process an EAP-MSCHAPv2 success message 333 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 334 * @data: Pointer to private EAP method data from eap_mschapv2_init() 335 * @ret: Return values from EAP request validation and processing 336 * @req: Pointer to EAP-MSCHAPv2 header from the request 337 * @req_len: Length of the EAP-MSCHAPv2 data 338 * @id: EAP identifier used in th erequest 339 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 340 * no reply available 341 */ 342static struct wpabuf * eap_mschapv2_success(struct eap_sm *sm, 343 struct eap_mschapv2_data *data, 344 struct eap_method_ret *ret, 345 const struct eap_mschapv2_hdr *req, 346 size_t req_len, u8 id) 347{ 348 struct wpabuf *resp; 349 const u8 *pos; 350 size_t len; 351 352 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received success"); 353 len = req_len - sizeof(*req); 354 pos = (const u8 *) (req + 1); 355 if (!data->auth_response_valid || 356 mschapv2_verify_auth_response(data->auth_response, pos, len)) { 357 wpa_printf(MSG_WARNING, "EAP-MSCHAPV2: Invalid authenticator " 358 "response in success request"); 359 ret->methodState = METHOD_DONE; 360 ret->decision = DECISION_FAIL; 361 return NULL; 362 } 363 pos += 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN; 364 len -= 2 + 2 * MSCHAPV2_AUTH_RESPONSE_LEN; 365 while (len > 0 && *pos == ' ') { 366 pos++; 367 len--; 368 } 369 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Success message", 370 pos, len); 371 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Authentication succeeded"); 372 373 /* Note: Only op_code of the EAP-MSCHAPV2 header is included in success 374 * message. */ 375 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, 1, 376 EAP_CODE_RESPONSE, id); 377 if (resp == NULL) { 378 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Failed to allocate " 379 "buffer for success response"); 380 ret->ignore = TRUE; 381 return NULL; 382 } 383 384 wpabuf_put_u8(resp, MSCHAPV2_OP_SUCCESS); /* op_code */ 385 386 ret->methodState = METHOD_DONE; 387 ret->decision = DECISION_UNCOND_SUCC; 388 ret->allowNotifications = FALSE; 389 data->success = 1; 390 391 if (data->prev_error == ERROR_PASSWD_EXPIRED) 392 eap_mschapv2_password_changed(sm, data); 393 394 return resp; 395} 396 397 398static int eap_mschapv2_failure_txt(struct eap_sm *sm, 399 struct eap_mschapv2_data *data, char *txt) 400{ 401 char *pos, *msg = ""; 402 int retry = 1; 403 struct eap_peer_config *config = eap_get_config(sm); 404 405 /* For example: 406 * E=691 R=1 C=<32 octets hex challenge> V=3 M=Authentication Failure 407 */ 408 409 pos = txt; 410 411 if (pos && os_strncmp(pos, "E=", 2) == 0) { 412 pos += 2; 413 data->prev_error = atoi(pos); 414 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: error %d", 415 data->prev_error); 416 pos = os_strchr(pos, ' '); 417 if (pos) 418 pos++; 419 } 420 421 if (pos && os_strncmp(pos, "R=", 2) == 0) { 422 pos += 2; 423 retry = atoi(pos); 424 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: retry is %sallowed", 425 retry == 1 ? "" : "not "); 426 pos = os_strchr(pos, ' '); 427 if (pos) 428 pos++; 429 } 430 431 if (pos && os_strncmp(pos, "C=", 2) == 0) { 432 int hex_len; 433 pos += 2; 434 hex_len = os_strchr(pos, ' ') - (char *) pos; 435 if (hex_len == PASSWD_CHANGE_CHAL_LEN * 2) { 436 if (hexstr2bin(pos, data->passwd_change_challenge, 437 PASSWD_CHANGE_CHAL_LEN)) { 438 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: invalid " 439 "failure challenge"); 440 } else { 441 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: failure " 442 "challenge", 443 data->passwd_change_challenge, 444 PASSWD_CHANGE_CHAL_LEN); 445 data->passwd_change_challenge_valid = 1; 446 } 447 } else { 448 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: invalid failure " 449 "challenge len %d", hex_len); 450 } 451 pos = os_strchr(pos, ' '); 452 if (pos) 453 pos++; 454 } else { 455 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: required challenge field " 456 "was not present in failure message"); 457 } 458 459 if (pos && os_strncmp(pos, "V=", 2) == 0) { 460 pos += 2; 461 data->passwd_change_version = atoi(pos); 462 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: password changing " 463 "protocol version %d", data->passwd_change_version); 464 pos = os_strchr(pos, ' '); 465 if (pos) 466 pos++; 467 } 468 469 if (pos && os_strncmp(pos, "M=", 2) == 0) { 470 pos += 2; 471 msg = pos; 472 } 473 wpa_msg(sm->msg_ctx, MSG_WARNING, 474 "EAP-MSCHAPV2: failure message: '%s' (retry %sallowed, error " 475 "%d)", 476 msg, retry == 1 ? "" : "not ", data->prev_error); 477 if (data->prev_error == ERROR_PASSWD_EXPIRED && 478 data->passwd_change_version == 3 && config) { 479 if (config->new_password == NULL) { 480 wpa_msg(sm->msg_ctx, MSG_INFO, 481 "EAP-MSCHAPV2: Password expired - password " 482 "change required"); 483 eap_sm_request_new_password(sm); 484 } 485 } else if (retry == 1 && config) { 486 /* TODO: could prevent the current password from being used 487 * again at least for some period of time */ 488 if (!config->mschapv2_retry) 489 eap_sm_request_identity(sm); 490 eap_sm_request_password(sm); 491 config->mschapv2_retry = 1; 492 } else if (config) { 493 /* TODO: prevent retries using same username/password */ 494 config->mschapv2_retry = 0; 495 } 496 497 return retry == 1; 498} 499 500 501static struct wpabuf * eap_mschapv2_change_password( 502 struct eap_sm *sm, struct eap_mschapv2_data *data, 503 struct eap_method_ret *ret, const struct eap_mschapv2_hdr *req, u8 id) 504{ 505 struct wpabuf *resp; 506 int ms_len; 507 const u8 *username, *password, *new_password; 508 size_t username_len, password_len, new_password_len; 509 struct eap_mschapv2_hdr *ms; 510 struct ms_change_password *cp; 511 u8 password_hash[16], password_hash_hash[16]; 512 int pwhash; 513 514 username = eap_get_config_identity(sm, &username_len); 515 password = eap_get_config_password2(sm, &password_len, &pwhash); 516 new_password = eap_get_config_new_password(sm, &new_password_len); 517 if (username == NULL || password == NULL || new_password == NULL) 518 return NULL; 519 520 username = mschapv2_remove_domain(username, &username_len); 521 522 ret->ignore = FALSE; 523 ret->methodState = METHOD_MAY_CONT; 524 ret->decision = DECISION_COND_SUCC; 525 ret->allowNotifications = TRUE; 526 527 ms_len = sizeof(*ms) + sizeof(*cp); 528 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, ms_len, 529 EAP_CODE_RESPONSE, id); 530 if (resp == NULL) 531 return NULL; 532 533 ms = wpabuf_put(resp, sizeof(*ms)); 534 ms->op_code = MSCHAPV2_OP_CHANGE_PASSWORD; 535 ms->mschapv2_id = req->mschapv2_id + 1; 536 WPA_PUT_BE16(ms->ms_length, ms_len); 537 cp = wpabuf_put(resp, sizeof(*cp)); 538 539 /* Encrypted-Password */ 540 if (pwhash) { 541 if (encrypt_pw_block_with_password_hash( 542 new_password, new_password_len, 543 password, cp->encr_password)) 544 goto fail; 545 } else { 546 if (new_password_encrypted_with_old_nt_password_hash( 547 new_password, new_password_len, 548 password, password_len, cp->encr_password)) 549 goto fail; 550 } 551 552 /* Encrypted-Hash */ 553 if (pwhash) { 554 u8 new_password_hash[16]; 555 if (nt_password_hash(new_password, new_password_len, 556 new_password_hash)) 557 goto fail; 558 nt_password_hash_encrypted_with_block(password, 559 new_password_hash, 560 cp->encr_hash); 561 } else { 562 if (old_nt_password_hash_encrypted_with_new_nt_password_hash( 563 new_password, new_password_len, 564 password, password_len, cp->encr_hash)) 565 goto fail; 566 } 567 568 /* Peer-Challenge */ 569 if (random_get_bytes(cp->peer_challenge, MSCHAPV2_CHAL_LEN)) 570 goto fail; 571 572 /* Reserved, must be zero */ 573 os_memset(cp->reserved, 0, 8); 574 575 /* NT-Response */ 576 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: auth_challenge", 577 data->passwd_change_challenge, PASSWD_CHANGE_CHAL_LEN); 578 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: peer_challenge", 579 cp->peer_challenge, MSCHAPV2_CHAL_LEN); 580 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: username", 581 username, username_len); 582 wpa_hexdump_ascii_key(MSG_DEBUG, "EAP-MSCHAPV2: new password", 583 new_password, new_password_len); 584 generate_nt_response(data->passwd_change_challenge, cp->peer_challenge, 585 username, username_len, 586 new_password, new_password_len, 587 cp->nt_response); 588 wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: NT-Response", 589 cp->nt_response, MSCHAPV2_NT_RESPONSE_LEN); 590 591 /* Authenticator response is not really needed yet, but calculate it 592 * here so that challenges need not be saved. */ 593 generate_authenticator_response(new_password, new_password_len, 594 cp->peer_challenge, 595 data->passwd_change_challenge, 596 username, username_len, 597 cp->nt_response, data->auth_response); 598 data->auth_response_valid = 1; 599 600 /* Likewise, generate master_key here since we have the needed data 601 * available. */ 602 if (nt_password_hash(new_password, new_password_len, password_hash) || 603 hash_nt_password_hash(password_hash, password_hash_hash) || 604 get_master_key(password_hash_hash, cp->nt_response, 605 data->master_key)) { 606 data->auth_response_valid = 0; 607 goto fail; 608 } 609 data->master_key_valid = 1; 610 611 /* Flags */ 612 os_memset(cp->flags, 0, 2); 613 614 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: TX identifier %d mschapv2_id %d " 615 "(change pw)", id, ms->mschapv2_id); 616 617 return resp; 618 619fail: 620 wpabuf_free(resp); 621 return NULL; 622} 623 624 625/** 626 * eap_mschapv2_process - Process an EAP-MSCHAPv2 failure message 627 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 628 * @data: Pointer to private EAP method data from eap_mschapv2_init() 629 * @ret: Return values from EAP request validation and processing 630 * @req: Pointer to EAP-MSCHAPv2 header from the request 631 * @req_len: Length of the EAP-MSCHAPv2 data 632 * @id: EAP identifier used in th erequest 633 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 634 * no reply available 635 */ 636static struct wpabuf * eap_mschapv2_failure(struct eap_sm *sm, 637 struct eap_mschapv2_data *data, 638 struct eap_method_ret *ret, 639 const struct eap_mschapv2_hdr *req, 640 size_t req_len, u8 id) 641{ 642 struct wpabuf *resp; 643 const u8 *msdata = (const u8 *) (req + 1); 644 char *buf; 645 size_t len = req_len - sizeof(*req); 646 int retry = 0; 647 648 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received failure"); 649 wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Failure data", 650 msdata, len); 651 /* 652 * eap_mschapv2_failure_txt() expects a nul terminated string, so we 653 * must allocate a large enough temporary buffer to create that since 654 * the received message does not include nul termination. 655 */ 656 buf = dup_binstr(msdata, len); 657 if (buf) { 658 retry = eap_mschapv2_failure_txt(sm, data, buf); 659 os_free(buf); 660 } 661 662 ret->ignore = FALSE; 663 ret->methodState = METHOD_DONE; 664 ret->decision = DECISION_FAIL; 665 ret->allowNotifications = FALSE; 666 667 if (data->prev_error == ERROR_PASSWD_EXPIRED && 668 data->passwd_change_version == 3) { 669 struct eap_peer_config *config = eap_get_config(sm); 670 if (config && config->new_password) 671 return eap_mschapv2_change_password(sm, data, ret, req, 672 id); 673 if (config && config->pending_req_new_password) 674 return NULL; 675 } else if (retry && data->prev_error == ERROR_AUTHENTICATION_FAILURE) { 676 /* TODO: could try to retry authentication, e.g, after having 677 * changed the username/password. In this case, EAP MS-CHAP-v2 678 * Failure Response would not be sent here. */ 679 return NULL; 680 } 681 682 /* Note: Only op_code of the EAP-MSCHAPV2 header is included in failure 683 * message. */ 684 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, 1, 685 EAP_CODE_RESPONSE, id); 686 if (resp == NULL) 687 return NULL; 688 689 wpabuf_put_u8(resp, MSCHAPV2_OP_FAILURE); /* op_code */ 690 691 return resp; 692} 693 694 695static int eap_mschapv2_check_config(struct eap_sm *sm) 696{ 697 size_t len; 698 699 if (eap_get_config_identity(sm, &len) == NULL) { 700 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Identity not configured"); 701 eap_sm_request_identity(sm); 702 return -1; 703 } 704 705 if (eap_get_config_password(sm, &len) == NULL) { 706 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Password not configured"); 707 eap_sm_request_password(sm); 708 return -1; 709 } 710 711 return 0; 712} 713 714 715static int eap_mschapv2_check_mslen(struct eap_sm *sm, size_t len, 716 const struct eap_mschapv2_hdr *ms) 717{ 718 size_t ms_len = WPA_GET_BE16(ms->ms_length); 719 720 if (ms_len == len) 721 return 0; 722 723 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Invalid header: len=%lu " 724 "ms_len=%lu", (unsigned long) len, (unsigned long) ms_len); 725 if (sm->workaround) { 726 /* Some authentication servers use invalid ms_len, 727 * ignore it for interoperability. */ 728 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: workaround, ignore" 729 " invalid ms_len %lu (len %lu)", 730 (unsigned long) ms_len, 731 (unsigned long) len); 732 return 0; 733 } 734 735 return -1; 736} 737 738 739static void eap_mschapv2_copy_challenge(struct eap_mschapv2_data *data, 740 const struct wpabuf *reqData) 741{ 742 /* 743 * Store a copy of the challenge message, so that it can be processed 744 * again in case retry is allowed after a possible failure. 745 */ 746 wpabuf_free(data->prev_challenge); 747 data->prev_challenge = wpabuf_dup(reqData); 748} 749 750 751/** 752 * eap_mschapv2_process - Process an EAP-MSCHAPv2 request 753 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 754 * @priv: Pointer to private EAP method data from eap_mschapv2_init() 755 * @ret: Return values from EAP request validation and processing 756 * @reqData: EAP request to be processed (eapReqData) 757 * Returns: Pointer to allocated EAP response packet (eapRespData) or %NULL if 758 * no reply available 759 */ 760static struct wpabuf * eap_mschapv2_process(struct eap_sm *sm, void *priv, 761 struct eap_method_ret *ret, 762 const struct wpabuf *reqData) 763{ 764 struct eap_mschapv2_data *data = priv; 765 struct eap_peer_config *config = eap_get_config(sm); 766 const struct eap_mschapv2_hdr *ms; 767 int using_prev_challenge = 0; 768 const u8 *pos; 769 size_t len; 770 u8 id; 771 772 if (eap_mschapv2_check_config(sm)) { 773 ret->ignore = TRUE; 774 return NULL; 775 } 776 777 if (config->mschapv2_retry && data->prev_challenge && 778 data->prev_error == ERROR_AUTHENTICATION_FAILURE) { 779 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Replacing pending packet " 780 "with the previous challenge"); 781 782 reqData = data->prev_challenge; 783 using_prev_challenge = 1; 784 config->mschapv2_retry = 0; 785 } 786 787 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, reqData, 788 &len); 789 if (pos == NULL || len < sizeof(*ms) + 1) { 790 ret->ignore = TRUE; 791 return NULL; 792 } 793 794 ms = (const struct eap_mschapv2_hdr *) pos; 795 if (eap_mschapv2_check_mslen(sm, len, ms)) { 796 ret->ignore = TRUE; 797 return NULL; 798 } 799 800 id = eap_get_id(reqData); 801 wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: RX identifier %d mschapv2_id %d", 802 id, ms->mschapv2_id); 803 804 switch (ms->op_code) { 805 case MSCHAPV2_OP_CHALLENGE: 806 if (!using_prev_challenge) 807 eap_mschapv2_copy_challenge(data, reqData); 808 return eap_mschapv2_challenge(sm, data, ret, ms, len, id); 809 case MSCHAPV2_OP_SUCCESS: 810 return eap_mschapv2_success(sm, data, ret, ms, len, id); 811 case MSCHAPV2_OP_FAILURE: 812 return eap_mschapv2_failure(sm, data, ret, ms, len, id); 813 default: 814 wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Unknown op %d - ignored", 815 ms->op_code); 816 ret->ignore = TRUE; 817 return NULL; 818 } 819} 820 821 822static Boolean eap_mschapv2_isKeyAvailable(struct eap_sm *sm, void *priv) 823{ 824 struct eap_mschapv2_data *data = priv; 825 return data->success && data->master_key_valid; 826} 827 828 829static u8 * eap_mschapv2_getKey(struct eap_sm *sm, void *priv, size_t *len) 830{ 831 struct eap_mschapv2_data *data = priv; 832 u8 *key; 833 int key_len; 834 835 if (!data->master_key_valid || !data->success) 836 return NULL; 837 838 key_len = 2 * MSCHAPV2_KEY_LEN; 839 840 key = os_malloc(key_len); 841 if (key == NULL) 842 return NULL; 843 844 /* MSK = server MS-MPPE-Recv-Key | MS-MPPE-Send-Key, i.e., 845 * peer MS-MPPE-Send-Key | MS-MPPE-Recv-Key */ 846 get_asymetric_start_key(data->master_key, key, MSCHAPV2_KEY_LEN, 1, 0); 847 get_asymetric_start_key(data->master_key, key + MSCHAPV2_KEY_LEN, 848 MSCHAPV2_KEY_LEN, 0, 0); 849 850 wpa_hexdump_key(MSG_DEBUG, "EAP-MSCHAPV2: Derived key", 851 key, key_len); 852 853 *len = key_len; 854 return key; 855} 856 857 858/** 859 * eap_peer_mschapv2_register - Register EAP-MSCHAPv2 peer method 860 * Returns: 0 on success, -1 on failure 861 * 862 * This function is used to register EAP-MSCHAPv2 peer method into the EAP 863 * method list. 864 */ 865int eap_peer_mschapv2_register(void) 866{ 867 struct eap_method *eap; 868 int ret; 869 870 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION, 871 EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, 872 "MSCHAPV2"); 873 if (eap == NULL) 874 return -1; 875 876 eap->init = eap_mschapv2_init; 877 eap->deinit = eap_mschapv2_deinit; 878 eap->process = eap_mschapv2_process; 879 eap->isKeyAvailable = eap_mschapv2_isKeyAvailable; 880 eap->getKey = eap_mschapv2_getKey; 881 882 ret = eap_peer_method_register(eap); 883 if (ret) 884 eap_peer_method_free(eap); 885 return ret; 886} 887