1 /* 2 * EAP peer method: EAP-pwd (RFC 5931) 3 * Copyright (c) 2010, Dan Harkins <dharkins@lounge.org> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the BSD license. 7 * 8 * Alternatively, this software may be distributed under the terms of the 9 * GNU General Public License version 2 as published by the Free Software 10 * Foundation. 11 * 12 * See README and COPYING for more details. 13 */ 14 15 #include "includes.h" 16 17 #include "common.h" 18 #include "eap_peer/eap_i.h" 19 #include "eap_common/eap_pwd_common.h" 20 21 22 struct eap_pwd_data { 23 enum { 24 PWD_ID_Req, PWD_Commit_Req, PWD_Confirm_Req, SUCCESS, FAILURE 25 } state; 26 u8 *id_peer; 27 size_t id_peer_len; 28 u8 *id_server; 29 size_t id_server_len; 30 u8 *password; 31 size_t password_len; 32 u16 group_num; 33 EAP_PWD_group *grp; 34 35 BIGNUM *k; 36 BIGNUM *private_value; 37 BIGNUM *server_scalar; 38 BIGNUM *my_scalar; 39 EC_POINT *my_element; 40 EC_POINT *server_element; 41 42 u8 msk[EAP_MSK_LEN]; 43 u8 emsk[EAP_EMSK_LEN]; 44 45 BN_CTX *bnctx; 46 }; 47 48 49 #ifndef CONFIG_NO_STDOUT_DEBUG 50 static const char * eap_pwd_state_txt(int state) 51 { 52 switch (state) { 53 case PWD_ID_Req: 54 return "PWD-ID-Req"; 55 case PWD_Commit_Req: 56 return "PWD-Commit-Req"; 57 case PWD_Confirm_Req: 58 return "PWD-Confirm-Req"; 59 case SUCCESS: 60 return "SUCCESS"; 61 case FAILURE: 62 return "FAILURE"; 63 default: 64 return "PWD-UNK"; 65 } 66 } 67 #endif /* CONFIG_NO_STDOUT_DEBUG */ 68 69 70 static void eap_pwd_state(struct eap_pwd_data *data, int state) 71 { 72 wpa_printf(MSG_INFO, "EAP-PWD: %s -> %s", 73 eap_pwd_state_txt(data->state), eap_pwd_state_txt(state)); 74 data->state = state; 75 } 76 77 78 static void * eap_pwd_init(struct eap_sm *sm) 79 { 80 struct eap_pwd_data *data; 81 const u8 *identity, *password; 82 size_t identity_len, password_len; 83 84 password = eap_get_config_password(sm, &password_len); 85 if (password == NULL) { 86 wpa_printf(MSG_INFO, "EAP-PWD: No password configured!"); 87 return NULL; 88 } 89 90 identity = eap_get_config_identity(sm, &identity_len); 91 if (identity == NULL) { 92 wpa_printf(MSG_INFO, "EAP-PWD: No identity configured!"); 93 return NULL; 94 } 95 96 if ((data = os_zalloc(sizeof(*data))) == NULL) { 97 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation data fail"); 98 return NULL; 99 } 100 101 if ((data->bnctx = BN_CTX_new()) == NULL) { 102 wpa_printf(MSG_INFO, "EAP-PWD: bn context allocation fail"); 103 os_free(data); 104 return NULL; 105 } 106 107 if ((data->id_peer = os_malloc(identity_len)) == NULL) { 108 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail"); 109 BN_CTX_free(data->bnctx); 110 os_free(data); 111 return NULL; 112 } 113 114 os_memcpy(data->id_peer, identity, identity_len); 115 data->id_peer_len = identity_len; 116 117 if ((data->password = os_malloc(password_len)) == NULL) { 118 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation psk fail"); 119 BN_CTX_free(data->bnctx); 120 os_free(data->id_peer); 121 os_free(data); 122 return NULL; 123 } 124 os_memcpy(data->password, password, password_len); 125 data->password_len = password_len; 126 127 data->state = PWD_ID_Req; 128 129 return data; 130 } 131 132 133 static void eap_pwd_deinit(struct eap_sm *sm, void *priv) 134 { 135 struct eap_pwd_data *data = priv; 136 137 BN_free(data->private_value); 138 BN_free(data->server_scalar); 139 BN_free(data->my_scalar); 140 BN_free(data->k); 141 BN_CTX_free(data->bnctx); 142 EC_POINT_free(data->my_element); 143 EC_POINT_free(data->server_element); 144 os_free(data->id_peer); 145 os_free(data->id_server); 146 os_free(data->password); 147 if (data->grp) { 148 EC_GROUP_free(data->grp->group); 149 EC_POINT_free(data->grp->pwe); 150 BN_free(data->grp->order); 151 BN_free(data->grp->prime); 152 os_free(data->grp); 153 } 154 os_free(data); 155 } 156 157 158 static u8 * eap_pwd_getkey(struct eap_sm *sm, void *priv, size_t *len) 159 { 160 struct eap_pwd_data *data = priv; 161 u8 *key; 162 163 if (data->state != SUCCESS) 164 return NULL; 165 166 key = os_malloc(EAP_MSK_LEN); 167 if (key == NULL) 168 return NULL; 169 170 os_memcpy(key, data->msk, EAP_MSK_LEN); 171 *len = EAP_MSK_LEN; 172 173 return key; 174 } 175 176 177 static struct wpabuf * 178 eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data, 179 struct eap_method_ret *ret, 180 const struct wpabuf *reqData, 181 const u8 *payload, size_t payload_len) 182 { 183 struct eap_pwd_id *id; 184 struct wpabuf *resp; 185 186 if (data->state != PWD_ID_Req) { 187 ret->ignore = TRUE; 188 return NULL; 189 } 190 191 if (payload_len < sizeof(struct eap_pwd_id)) { 192 ret->ignore = TRUE; 193 return NULL; 194 } 195 196 id = (struct eap_pwd_id *) payload; 197 data->group_num = be_to_host16(id->group_num); 198 if ((id->random_function != EAP_PWD_DEFAULT_RAND_FUNC) || 199 (id->prf != EAP_PWD_DEFAULT_PRF)) { 200 ret->ignore = TRUE; 201 return NULL; 202 } 203 204 wpa_printf(MSG_DEBUG, "EAP-PWD (peer): server said group %d", 205 data->group_num); 206 207 data->id_server = os_malloc(payload_len - sizeof(struct eap_pwd_id)); 208 if (data->id_server == NULL) { 209 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail"); 210 return NULL; 211 } 212 data->id_server_len = payload_len - sizeof(struct eap_pwd_id); 213 os_memcpy(data->id_server, id->identity, data->id_server_len); 214 wpa_hexdump_ascii(MSG_INFO, "EAP-PWD (peer): server sent id of", 215 data->id_server, data->id_server_len); 216 217 if ((data->grp = (EAP_PWD_group *) os_malloc(sizeof(EAP_PWD_group))) == 218 NULL) { 219 wpa_printf(MSG_INFO, "EAP-PWD: failed to allocate memory for " 220 "group"); 221 return NULL; 222 } 223 224 /* compute PWE */ 225 if (compute_password_element(data->grp, data->group_num, 226 data->password, data->password_len, 227 data->id_server, data->id_server_len, 228 data->id_peer, data->id_peer_len, 229 id->token)) { 230 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute PWE"); 231 return NULL; 232 } 233 234 wpa_printf(MSG_INFO, "EAP-PWD (peer): computed %d bit PWE...", 235 BN_num_bits(data->grp->prime)); 236 237 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, 238 1 + sizeof(struct eap_pwd_id) + data->id_peer_len, 239 EAP_CODE_RESPONSE, eap_get_id(reqData)); 240 if (resp == NULL) 241 return NULL; 242 243 wpabuf_put_u8(resp, EAP_PWD_OPCODE_ID_EXCH); 244 wpabuf_put_be16(resp, data->group_num); 245 wpabuf_put_u8(resp, EAP_PWD_DEFAULT_RAND_FUNC); 246 wpabuf_put_u8(resp, EAP_PWD_DEFAULT_PRF); 247 wpabuf_put_data(resp, id->token, sizeof(id->token)); 248 wpabuf_put_u8(resp, EAP_PWD_PREP_NONE); 249 wpabuf_put_data(resp, data->id_peer, data->id_peer_len); 250 251 eap_pwd_state(data, PWD_Commit_Req); 252 253 return resp; 254 } 255 256 257 static struct wpabuf * 258 eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data, 259 struct eap_method_ret *ret, 260 const struct wpabuf *reqData, 261 const u8 *payload, size_t payload_len) 262 { 263 struct wpabuf *resp = NULL; 264 EC_POINT *K = NULL, *point = NULL; 265 BIGNUM *mask = NULL, *x = NULL, *y = NULL, *cofactor = NULL; 266 u16 offset; 267 u8 *ptr, *scalar = NULL, *element = NULL; 268 269 if (((data->private_value = BN_new()) == NULL) || 270 ((data->my_element = EC_POINT_new(data->grp->group)) == NULL) || 271 ((cofactor = BN_new()) == NULL) || 272 ((data->my_scalar = BN_new()) == NULL) || 273 ((mask = BN_new()) == NULL)) { 274 wpa_printf(MSG_INFO, "EAP-PWD (peer): scalar allocation fail"); 275 goto fin; 276 } 277 278 if (!EC_GROUP_get_cofactor(data->grp->group, cofactor, NULL)) { 279 wpa_printf(MSG_INFO, "EAP-pwd (peer): unable to get cofactor " 280 "for curve"); 281 goto fin; 282 } 283 284 BN_rand_range(data->private_value, data->grp->order); 285 BN_rand_range(mask, data->grp->order); 286 BN_add(data->my_scalar, data->private_value, mask); 287 BN_mod(data->my_scalar, data->my_scalar, data->grp->order, 288 data->bnctx); 289 290 if (!EC_POINT_mul(data->grp->group, data->my_element, NULL, 291 data->grp->pwe, mask, data->bnctx)) { 292 wpa_printf(MSG_INFO, "EAP-PWD (peer): element allocation " 293 "fail"); 294 eap_pwd_state(data, FAILURE); 295 goto fin; 296 } 297 298 if (!EC_POINT_invert(data->grp->group, data->my_element, data->bnctx)) 299 { 300 wpa_printf(MSG_INFO, "EAP-PWD (peer): element inversion fail"); 301 goto fin; 302 } 303 BN_free(mask); 304 305 if (((x = BN_new()) == NULL) || 306 ((y = BN_new()) == NULL)) { 307 wpa_printf(MSG_INFO, "EAP-PWD (peer): point allocation fail"); 308 goto fin; 309 } 310 311 /* process the request */ 312 if (((data->server_scalar = BN_new()) == NULL) || 313 ((data->k = BN_new()) == NULL) || 314 ((K = EC_POINT_new(data->grp->group)) == NULL) || 315 ((point = EC_POINT_new(data->grp->group)) == NULL) || 316 ((data->server_element = EC_POINT_new(data->grp->group)) == NULL)) 317 { 318 wpa_printf(MSG_INFO, "EAP-PWD (peer): peer data allocation " 319 "fail"); 320 goto fin; 321 } 322 323 /* element, x then y, followed by scalar */ 324 ptr = (u8 *) payload; 325 BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), x); 326 ptr += BN_num_bytes(data->grp->prime); 327 BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), y); 328 ptr += BN_num_bytes(data->grp->prime); 329 BN_bin2bn(ptr, BN_num_bytes(data->grp->order), data->server_scalar); 330 if (!EC_POINT_set_affine_coordinates_GFp(data->grp->group, 331 data->server_element, x, y, 332 data->bnctx)) { 333 wpa_printf(MSG_INFO, "EAP-PWD (peer): setting peer element " 334 "fail"); 335 goto fin; 336 } 337 338 /* check to ensure server's element is not in a small sub-group */ 339 if (BN_cmp(cofactor, BN_value_one())) { 340 if (!EC_POINT_mul(data->grp->group, point, NULL, 341 data->server_element, cofactor, NULL)) { 342 wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply " 343 "server element by order!\n"); 344 goto fin; 345 } 346 if (EC_POINT_is_at_infinity(data->grp->group, point)) { 347 wpa_printf(MSG_INFO, "EAP-PWD (peer): server element " 348 "is at infinity!\n"); 349 goto fin; 350 } 351 } 352 353 /* compute the shared key, k */ 354 if ((!EC_POINT_mul(data->grp->group, K, NULL, data->grp->pwe, 355 data->server_scalar, data->bnctx)) || 356 (!EC_POINT_add(data->grp->group, K, K, data->server_element, 357 data->bnctx)) || 358 (!EC_POINT_mul(data->grp->group, K, NULL, K, data->private_value, 359 data->bnctx))) { 360 wpa_printf(MSG_INFO, "EAP-PWD (peer): computing shared key " 361 "fail"); 362 goto fin; 363 } 364 365 /* ensure that the shared key isn't in a small sub-group */ 366 if (BN_cmp(cofactor, BN_value_one())) { 367 if (!EC_POINT_mul(data->grp->group, K, NULL, K, cofactor, 368 NULL)) { 369 wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply " 370 "shared key point by order"); 371 goto fin; 372 } 373 } 374 375 /* 376 * This check is strictly speaking just for the case above where 377 * co-factor > 1 but it was suggested that even though this is probably 378 * never going to happen it is a simple and safe check "just to be 379 * sure" so let's be safe. 380 */ 381 if (EC_POINT_is_at_infinity(data->grp->group, K)) { 382 wpa_printf(MSG_INFO, "EAP-PWD (peer): shared key point is at " 383 "infinity!\n"); 384 goto fin; 385 } 386 387 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, K, data->k, 388 NULL, data->bnctx)) { 389 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to extract " 390 "shared secret from point"); 391 goto fin; 392 } 393 394 /* now do the response */ 395 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 396 data->my_element, x, y, 397 data->bnctx)) { 398 wpa_printf(MSG_INFO, "EAP-PWD (peer): point assignment fail"); 399 goto fin; 400 } 401 402 if (((scalar = os_malloc(BN_num_bytes(data->grp->order))) == NULL) || 403 ((element = os_malloc(BN_num_bytes(data->grp->prime) * 2)) == 404 NULL)) { 405 wpa_printf(MSG_INFO, "EAP-PWD (peer): data allocation fail"); 406 goto fin; 407 } 408 409 /* 410 * bignums occupy as little memory as possible so one that is 411 * sufficiently smaller than the prime or order might need pre-pending 412 * with zeros. 413 */ 414 os_memset(scalar, 0, BN_num_bytes(data->grp->order)); 415 os_memset(element, 0, BN_num_bytes(data->grp->prime) * 2); 416 offset = BN_num_bytes(data->grp->order) - 417 BN_num_bytes(data->my_scalar); 418 BN_bn2bin(data->my_scalar, scalar + offset); 419 420 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 421 BN_bn2bin(x, element + offset); 422 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 423 BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset); 424 425 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, 426 sizeof(struct eap_pwd_hdr) + 427 BN_num_bytes(data->grp->order) + 428 (2 * BN_num_bytes(data->grp->prime)), 429 EAP_CODE_RESPONSE, eap_get_id(reqData)); 430 if (resp == NULL) 431 goto fin; 432 433 wpabuf_put_u8(resp, EAP_PWD_OPCODE_COMMIT_EXCH); 434 435 /* we send the element as (x,y) follwed by the scalar */ 436 wpabuf_put_data(resp, element, (2 * BN_num_bytes(data->grp->prime))); 437 wpabuf_put_data(resp, scalar, BN_num_bytes(data->grp->order)); 438 439 fin: 440 os_free(scalar); 441 os_free(element); 442 BN_free(x); 443 BN_free(y); 444 BN_free(cofactor); 445 EC_POINT_free(K); 446 EC_POINT_free(point); 447 if (resp == NULL) 448 eap_pwd_state(data, FAILURE); 449 else 450 eap_pwd_state(data, PWD_Confirm_Req); 451 452 return resp; 453 } 454 455 456 static struct wpabuf * 457 eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data, 458 struct eap_method_ret *ret, 459 const struct wpabuf *reqData, 460 const u8 *payload, size_t payload_len) 461 { 462 struct wpabuf *resp = NULL; 463 BIGNUM *x = NULL, *y = NULL; 464 HMAC_CTX ctx; 465 u32 cs; 466 u16 grp; 467 u8 conf[SHA256_DIGEST_LENGTH], *cruft = NULL, *ptr; 468 int offset; 469 470 /* 471 * first build up the ciphersuite which is group | random_function | 472 * prf 473 */ 474 grp = htons(data->group_num); 475 ptr = (u8 *) &cs; 476 os_memcpy(ptr, &grp, sizeof(u16)); 477 ptr += sizeof(u16); 478 *ptr = EAP_PWD_DEFAULT_RAND_FUNC; 479 ptr += sizeof(u8); 480 *ptr = EAP_PWD_DEFAULT_PRF; 481 482 /* each component of the cruft will be at most as big as the prime */ 483 if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) || 484 ((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) { 485 wpa_printf(MSG_INFO, "EAP-PWD (server): debug allocation " 486 "fail"); 487 goto fin; 488 } 489 490 /* 491 * server's commit is H(k | server_element | server_scalar | 492 * peer_element | peer_scalar | ciphersuite) 493 */ 494 H_Init(&ctx); 495 496 /* 497 * zero the memory each time because this is mod prime math and some 498 * value may start with a few zeros and the previous one did not. 499 */ 500 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 501 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k); 502 BN_bn2bin(data->k, cruft + offset); 503 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 504 505 /* server element: x, y */ 506 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 507 data->server_element, x, y, 508 data->bnctx)) { 509 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point " 510 "assignment fail"); 511 goto fin; 512 } 513 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 514 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 515 BN_bn2bin(x, cruft + offset); 516 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 517 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 518 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 519 BN_bn2bin(y, cruft + offset); 520 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 521 522 /* server scalar */ 523 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 524 offset = BN_num_bytes(data->grp->order) - 525 BN_num_bytes(data->server_scalar); 526 BN_bn2bin(data->server_scalar, cruft + offset); 527 H_Update(&ctx, cruft, BN_num_bytes(data->grp->order)); 528 529 /* my element: x, y */ 530 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 531 data->my_element, x, y, 532 data->bnctx)) { 533 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point " 534 "assignment fail"); 535 goto fin; 536 } 537 538 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 539 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 540 BN_bn2bin(x, cruft + offset); 541 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 542 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 543 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 544 BN_bn2bin(y, cruft + offset); 545 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 546 547 /* my scalar */ 548 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 549 offset = BN_num_bytes(data->grp->order) - 550 BN_num_bytes(data->my_scalar); 551 BN_bn2bin(data->my_scalar, cruft + offset); 552 H_Update(&ctx, cruft, BN_num_bytes(data->grp->order)); 553 554 /* the ciphersuite */ 555 H_Update(&ctx, (u8 *) &cs, sizeof(u32)); 556 557 /* random function fin */ 558 H_Final(&ctx, conf); 559 560 ptr = (u8 *) payload; 561 if (os_memcmp(conf, ptr, SHA256_DIGEST_LENGTH)) { 562 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm did not verify"); 563 goto fin; 564 } 565 566 wpa_printf(MSG_DEBUG, "EAP-pwd (peer): confirm verified"); 567 568 /* 569 * compute confirm: 570 * H(k | peer_element | peer_scalar | server_element | server_scalar | 571 * ciphersuite) 572 */ 573 H_Init(&ctx); 574 575 /* k */ 576 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 577 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k); 578 BN_bn2bin(data->k, cruft + offset); 579 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 580 581 /* my element */ 582 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 583 data->my_element, x, y, 584 data->bnctx)) { 585 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point " 586 "assignment fail"); 587 goto fin; 588 } 589 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 590 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 591 BN_bn2bin(x, cruft + offset); 592 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 593 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 594 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 595 BN_bn2bin(y, cruft + offset); 596 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 597 598 /* my scalar */ 599 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 600 offset = BN_num_bytes(data->grp->order) - 601 BN_num_bytes(data->my_scalar); 602 BN_bn2bin(data->my_scalar, cruft + offset); 603 H_Update(&ctx, cruft, BN_num_bytes(data->grp->order)); 604 605 /* server element: x, y */ 606 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 607 data->server_element, x, y, 608 data->bnctx)) { 609 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point " 610 "assignment fail"); 611 goto fin; 612 } 613 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 614 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 615 BN_bn2bin(x, cruft + offset); 616 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 617 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 618 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 619 BN_bn2bin(y, cruft + offset); 620 H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime)); 621 622 /* server scalar */ 623 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 624 offset = BN_num_bytes(data->grp->order) - 625 BN_num_bytes(data->server_scalar); 626 BN_bn2bin(data->server_scalar, cruft + offset); 627 H_Update(&ctx, cruft, BN_num_bytes(data->grp->order)); 628 629 /* the ciphersuite */ 630 H_Update(&ctx, (u8 *) &cs, sizeof(u32)); 631 632 /* all done */ 633 H_Final(&ctx, conf); 634 635 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, 636 sizeof(struct eap_pwd_hdr) + SHA256_DIGEST_LENGTH, 637 EAP_CODE_RESPONSE, eap_get_id(reqData)); 638 if (resp == NULL) 639 goto fin; 640 641 wpabuf_put_u8(resp, EAP_PWD_OPCODE_CONFIRM_EXCH); 642 wpabuf_put_data(resp, conf, SHA256_DIGEST_LENGTH); 643 644 if (compute_keys(data->grp, data->bnctx, data->k, 645 data->my_scalar, data->server_scalar, conf, ptr, 646 &cs, data->msk, data->emsk) < 0) { 647 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute MSK | " 648 "EMSK"); 649 goto fin; 650 } 651 652 fin: 653 os_free(cruft); 654 BN_free(x); 655 BN_free(y); 656 ret->methodState = METHOD_DONE; 657 if (resp == NULL) { 658 ret->decision = DECISION_FAIL; 659 eap_pwd_state(data, FAILURE); 660 } else { 661 ret->decision = DECISION_UNCOND_SUCC; 662 eap_pwd_state(data, SUCCESS); 663 } 664 665 return resp; 666 } 667 668 669 static struct wpabuf * 670 eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret, 671 const struct wpabuf *reqData) 672 { 673 struct eap_pwd_data *data = priv; 674 struct wpabuf *resp = NULL; 675 const u8 *pos; 676 size_t len; 677 u8 exch; 678 679 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, reqData, &len); 680 if ((pos == NULL) || (len < 1)) { 681 ret->ignore = TRUE; 682 return NULL; 683 } 684 685 wpa_printf(MSG_INFO, "EAP-pwd: Received frame: opcode %d", *pos); 686 687 ret->ignore = FALSE; 688 ret->methodState = METHOD_MAY_CONT; 689 ret->decision = DECISION_FAIL; 690 ret->allowNotifications = FALSE; 691 692 exch = *pos & 0x3f; 693 switch (exch) { 694 case EAP_PWD_OPCODE_ID_EXCH: 695 resp = eap_pwd_perform_id_exchange(sm, data, ret, reqData, 696 pos + 1, len - 1); 697 break; 698 case EAP_PWD_OPCODE_COMMIT_EXCH: 699 resp = eap_pwd_perform_commit_exchange(sm, data, ret, reqData, 700 pos + 1, len - 1); 701 break; 702 case EAP_PWD_OPCODE_CONFIRM_EXCH: 703 resp = eap_pwd_perform_confirm_exchange(sm, data, ret, reqData, 704 pos + 1, len - 1); 705 break; 706 default: 707 wpa_printf(MSG_INFO, "EAP-pwd: Ignoring message with unknown " 708 "opcode %d", exch); 709 break; 710 } 711 712 return resp; 713 } 714 715 716 static Boolean eap_pwd_key_available(struct eap_sm *sm, void *priv) 717 { 718 struct eap_pwd_data *data = priv; 719 return data->state == SUCCESS; 720 } 721 722 723 static u8 * eap_pwd_get_emsk(struct eap_sm *sm, void *priv, size_t *len) 724 { 725 struct eap_pwd_data *data = priv; 726 u8 *key; 727 728 if (data->state != SUCCESS) 729 return NULL; 730 731 if ((key = os_malloc(EAP_EMSK_LEN)) == NULL) 732 return NULL; 733 734 os_memcpy(key, data->emsk, EAP_EMSK_LEN); 735 *len = EAP_EMSK_LEN; 736 737 return key; 738 } 739 740 741 int eap_peer_pwd_register(void) 742 { 743 struct eap_method *eap; 744 int ret; 745 746 EVP_add_digest(EVP_sha256()); 747 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION, 748 EAP_VENDOR_IETF, EAP_TYPE_PWD, "PWD"); 749 if (eap == NULL) 750 return -1; 751 752 eap->init = eap_pwd_init; 753 eap->deinit = eap_pwd_deinit; 754 eap->process = eap_pwd_process; 755 eap->isKeyAvailable = eap_pwd_key_available; 756 eap->getKey = eap_pwd_getkey; 757 eap->get_emsk = eap_pwd_get_emsk; 758 759 ret = eap_peer_method_register(eap); 760 if (ret) 761 eap_peer_method_free(eap); 762 return ret; 763 } 764