eap_pwd.c revision 21de214b4ba4271ca20843f3b8fba9f1501b2a89
1/* 2 * EAP peer method: EAP-pwd (RFC 5931) 3 * Copyright (c) 2010, Dan Harkins <dharkins@lounge.org> 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9#include "includes.h" 10 11#include "common.h" 12#include "crypto/sha256.h" 13#include "eap_peer/eap_i.h" 14#include "eap_common/eap_pwd_common.h" 15 16 17struct eap_pwd_data { 18 enum { 19 PWD_ID_Req, PWD_Commit_Req, PWD_Confirm_Req, 20 SUCCESS_ON_FRAG_COMPLETION, SUCCESS, FAILURE 21 } state; 22 u8 *id_peer; 23 size_t id_peer_len; 24 u8 *id_server; 25 size_t id_server_len; 26 u8 *password; 27 size_t password_len; 28 u16 group_num; 29 EAP_PWD_group *grp; 30 31 struct wpabuf *inbuf; 32 size_t in_frag_pos; 33 struct wpabuf *outbuf; 34 size_t out_frag_pos; 35 size_t mtu; 36 37 BIGNUM *k; 38 BIGNUM *private_value; 39 BIGNUM *server_scalar; 40 BIGNUM *my_scalar; 41 EC_POINT *my_element; 42 EC_POINT *server_element; 43 44 u8 msk[EAP_MSK_LEN]; 45 u8 emsk[EAP_EMSK_LEN]; 46 47 BN_CTX *bnctx; 48}; 49 50 51#ifndef CONFIG_NO_STDOUT_DEBUG 52static const char * eap_pwd_state_txt(int state) 53{ 54 switch (state) { 55 case PWD_ID_Req: 56 return "PWD-ID-Req"; 57 case PWD_Commit_Req: 58 return "PWD-Commit-Req"; 59 case PWD_Confirm_Req: 60 return "PWD-Confirm-Req"; 61 case SUCCESS_ON_FRAG_COMPLETION: 62 return "SUCCESS_ON_FRAG_COMPLETION"; 63 case SUCCESS: 64 return "SUCCESS"; 65 case FAILURE: 66 return "FAILURE"; 67 default: 68 return "PWD-UNK"; 69 } 70} 71#endif /* CONFIG_NO_STDOUT_DEBUG */ 72 73 74static void eap_pwd_state(struct eap_pwd_data *data, int state) 75{ 76 wpa_printf(MSG_DEBUG, "EAP-PWD: %s -> %s", 77 eap_pwd_state_txt(data->state), eap_pwd_state_txt(state)); 78 data->state = state; 79} 80 81 82static void * eap_pwd_init(struct eap_sm *sm) 83{ 84 struct eap_pwd_data *data; 85 const u8 *identity, *password; 86 size_t identity_len, password_len; 87 int fragment_size; 88 89 password = eap_get_config_password(sm, &password_len); 90 if (password == NULL) { 91 wpa_printf(MSG_INFO, "EAP-PWD: No password configured!"); 92 return NULL; 93 } 94 95 identity = eap_get_config_identity(sm, &identity_len); 96 if (identity == NULL) { 97 wpa_printf(MSG_INFO, "EAP-PWD: No identity configured!"); 98 return NULL; 99 } 100 101 if ((data = os_zalloc(sizeof(*data))) == NULL) { 102 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation data fail"); 103 return NULL; 104 } 105 106 if ((data->bnctx = BN_CTX_new()) == NULL) { 107 wpa_printf(MSG_INFO, "EAP-PWD: bn context allocation fail"); 108 os_free(data); 109 return NULL; 110 } 111 112 if ((data->id_peer = os_malloc(identity_len)) == NULL) { 113 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail"); 114 BN_CTX_free(data->bnctx); 115 os_free(data); 116 return NULL; 117 } 118 119 os_memcpy(data->id_peer, identity, identity_len); 120 data->id_peer_len = identity_len; 121 122 if ((data->password = os_malloc(password_len)) == NULL) { 123 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation psk fail"); 124 BN_CTX_free(data->bnctx); 125 os_free(data->id_peer); 126 os_free(data); 127 return NULL; 128 } 129 os_memcpy(data->password, password, password_len); 130 data->password_len = password_len; 131 132 data->out_frag_pos = data->in_frag_pos = 0; 133 data->inbuf = data->outbuf = NULL; 134 fragment_size = eap_get_config_fragment_size(sm); 135 if (fragment_size <= 0) 136 data->mtu = 1020; /* default from RFC 5931 */ 137 else 138 data->mtu = fragment_size; 139 140 data->state = PWD_ID_Req; 141 142 return data; 143} 144 145 146static void eap_pwd_deinit(struct eap_sm *sm, void *priv) 147{ 148 struct eap_pwd_data *data = priv; 149 150 BN_free(data->private_value); 151 BN_free(data->server_scalar); 152 BN_free(data->my_scalar); 153 BN_free(data->k); 154 BN_CTX_free(data->bnctx); 155 EC_POINT_free(data->my_element); 156 EC_POINT_free(data->server_element); 157 os_free(data->id_peer); 158 os_free(data->id_server); 159 os_free(data->password); 160 if (data->grp) { 161 EC_GROUP_free(data->grp->group); 162 EC_POINT_free(data->grp->pwe); 163 BN_free(data->grp->order); 164 BN_free(data->grp->prime); 165 os_free(data->grp); 166 } 167 wpabuf_free(data->inbuf); 168 wpabuf_free(data->outbuf); 169 os_free(data); 170} 171 172 173static u8 * eap_pwd_getkey(struct eap_sm *sm, void *priv, size_t *len) 174{ 175 struct eap_pwd_data *data = priv; 176 u8 *key; 177 178 if (data->state != SUCCESS) 179 return NULL; 180 181 key = os_malloc(EAP_MSK_LEN); 182 if (key == NULL) 183 return NULL; 184 185 os_memcpy(key, data->msk, EAP_MSK_LEN); 186 *len = EAP_MSK_LEN; 187 188 return key; 189} 190 191 192static void 193eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data, 194 struct eap_method_ret *ret, 195 const struct wpabuf *reqData, 196 const u8 *payload, size_t payload_len) 197{ 198 struct eap_pwd_id *id; 199 200 if (data->state != PWD_ID_Req) { 201 ret->ignore = TRUE; 202 eap_pwd_state(data, FAILURE); 203 return; 204 } 205 206 if (payload_len < sizeof(struct eap_pwd_id)) { 207 ret->ignore = TRUE; 208 eap_pwd_state(data, FAILURE); 209 return; 210 } 211 212 id = (struct eap_pwd_id *) payload; 213 data->group_num = be_to_host16(id->group_num); 214 if ((id->random_function != EAP_PWD_DEFAULT_RAND_FUNC) || 215 (id->prf != EAP_PWD_DEFAULT_PRF)) { 216 ret->ignore = TRUE; 217 eap_pwd_state(data, FAILURE); 218 return; 219 } 220 221 wpa_printf(MSG_DEBUG, "EAP-PWD (peer): using group %d", 222 data->group_num); 223 224 data->id_server = os_malloc(payload_len - sizeof(struct eap_pwd_id)); 225 if (data->id_server == NULL) { 226 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail"); 227 eap_pwd_state(data, FAILURE); 228 return; 229 } 230 data->id_server_len = payload_len - sizeof(struct eap_pwd_id); 231 os_memcpy(data->id_server, id->identity, data->id_server_len); 232 wpa_hexdump_ascii(MSG_INFO, "EAP-PWD (peer): server sent id of", 233 data->id_server, data->id_server_len); 234 235 if ((data->grp = (EAP_PWD_group *) os_malloc(sizeof(EAP_PWD_group))) == 236 NULL) { 237 wpa_printf(MSG_INFO, "EAP-PWD: failed to allocate memory for " 238 "group"); 239 eap_pwd_state(data, FAILURE); 240 return; 241 } 242 243 /* compute PWE */ 244 if (compute_password_element(data->grp, data->group_num, 245 data->password, data->password_len, 246 data->id_server, data->id_server_len, 247 data->id_peer, data->id_peer_len, 248 id->token)) { 249 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute PWE"); 250 eap_pwd_state(data, FAILURE); 251 return; 252 } 253 254 wpa_printf(MSG_DEBUG, "EAP-PWD (peer): computed %d bit PWE...", 255 BN_num_bits(data->grp->prime)); 256 257 data->outbuf = wpabuf_alloc(sizeof(struct eap_pwd_id) + 258 data->id_peer_len); 259 if (data->outbuf == NULL) { 260 eap_pwd_state(data, FAILURE); 261 return; 262 } 263 wpabuf_put_be16(data->outbuf, data->group_num); 264 wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_RAND_FUNC); 265 wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_PRF); 266 wpabuf_put_data(data->outbuf, id->token, sizeof(id->token)); 267 wpabuf_put_u8(data->outbuf, EAP_PWD_PREP_NONE); 268 wpabuf_put_data(data->outbuf, data->id_peer, data->id_peer_len); 269 270 eap_pwd_state(data, PWD_Commit_Req); 271} 272 273 274static void 275eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data, 276 struct eap_method_ret *ret, 277 const struct wpabuf *reqData, 278 const u8 *payload, size_t payload_len) 279{ 280 EC_POINT *K = NULL, *point = NULL; 281 BIGNUM *mask = NULL, *x = NULL, *y = NULL, *cofactor = NULL; 282 u16 offset; 283 u8 *ptr, *scalar = NULL, *element = NULL; 284 285 if (((data->private_value = BN_new()) == NULL) || 286 ((data->my_element = EC_POINT_new(data->grp->group)) == NULL) || 287 ((cofactor = BN_new()) == NULL) || 288 ((data->my_scalar = BN_new()) == NULL) || 289 ((mask = BN_new()) == NULL)) { 290 wpa_printf(MSG_INFO, "EAP-PWD (peer): scalar allocation fail"); 291 goto fin; 292 } 293 294 if (!EC_GROUP_get_cofactor(data->grp->group, cofactor, NULL)) { 295 wpa_printf(MSG_INFO, "EAP-pwd (peer): unable to get cofactor " 296 "for curve"); 297 goto fin; 298 } 299 300 BN_rand_range(data->private_value, data->grp->order); 301 BN_rand_range(mask, data->grp->order); 302 BN_add(data->my_scalar, data->private_value, mask); 303 BN_mod(data->my_scalar, data->my_scalar, data->grp->order, 304 data->bnctx); 305 306 if (!EC_POINT_mul(data->grp->group, data->my_element, NULL, 307 data->grp->pwe, mask, data->bnctx)) { 308 wpa_printf(MSG_INFO, "EAP-PWD (peer): element allocation " 309 "fail"); 310 eap_pwd_state(data, FAILURE); 311 goto fin; 312 } 313 314 if (!EC_POINT_invert(data->grp->group, data->my_element, data->bnctx)) 315 { 316 wpa_printf(MSG_INFO, "EAP-PWD (peer): element inversion fail"); 317 goto fin; 318 } 319 BN_free(mask); 320 321 if (((x = BN_new()) == NULL) || 322 ((y = BN_new()) == NULL)) { 323 wpa_printf(MSG_INFO, "EAP-PWD (peer): point allocation fail"); 324 goto fin; 325 } 326 327 /* process the request */ 328 if (((data->server_scalar = BN_new()) == NULL) || 329 ((data->k = BN_new()) == NULL) || 330 ((K = EC_POINT_new(data->grp->group)) == NULL) || 331 ((point = EC_POINT_new(data->grp->group)) == NULL) || 332 ((data->server_element = EC_POINT_new(data->grp->group)) == NULL)) 333 { 334 wpa_printf(MSG_INFO, "EAP-PWD (peer): peer data allocation " 335 "fail"); 336 goto fin; 337 } 338 339 /* element, x then y, followed by scalar */ 340 ptr = (u8 *) payload; 341 BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), x); 342 ptr += BN_num_bytes(data->grp->prime); 343 BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), y); 344 ptr += BN_num_bytes(data->grp->prime); 345 BN_bin2bn(ptr, BN_num_bytes(data->grp->order), data->server_scalar); 346 if (!EC_POINT_set_affine_coordinates_GFp(data->grp->group, 347 data->server_element, x, y, 348 data->bnctx)) { 349 wpa_printf(MSG_INFO, "EAP-PWD (peer): setting peer element " 350 "fail"); 351 goto fin; 352 } 353 354 /* check to ensure server's element is not in a small sub-group */ 355 if (BN_cmp(cofactor, BN_value_one())) { 356 if (!EC_POINT_mul(data->grp->group, point, NULL, 357 data->server_element, cofactor, NULL)) { 358 wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply " 359 "server element by order!\n"); 360 goto fin; 361 } 362 if (EC_POINT_is_at_infinity(data->grp->group, point)) { 363 wpa_printf(MSG_INFO, "EAP-PWD (peer): server element " 364 "is at infinity!\n"); 365 goto fin; 366 } 367 } 368 369 /* compute the shared key, k */ 370 if ((!EC_POINT_mul(data->grp->group, K, NULL, data->grp->pwe, 371 data->server_scalar, data->bnctx)) || 372 (!EC_POINT_add(data->grp->group, K, K, data->server_element, 373 data->bnctx)) || 374 (!EC_POINT_mul(data->grp->group, K, NULL, K, data->private_value, 375 data->bnctx))) { 376 wpa_printf(MSG_INFO, "EAP-PWD (peer): computing shared key " 377 "fail"); 378 goto fin; 379 } 380 381 /* ensure that the shared key isn't in a small sub-group */ 382 if (BN_cmp(cofactor, BN_value_one())) { 383 if (!EC_POINT_mul(data->grp->group, K, NULL, K, cofactor, 384 NULL)) { 385 wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply " 386 "shared key point by order"); 387 goto fin; 388 } 389 } 390 391 /* 392 * This check is strictly speaking just for the case above where 393 * co-factor > 1 but it was suggested that even though this is probably 394 * never going to happen it is a simple and safe check "just to be 395 * sure" so let's be safe. 396 */ 397 if (EC_POINT_is_at_infinity(data->grp->group, K)) { 398 wpa_printf(MSG_INFO, "EAP-PWD (peer): shared key point is at " 399 "infinity!\n"); 400 goto fin; 401 } 402 403 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, K, data->k, 404 NULL, data->bnctx)) { 405 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to extract " 406 "shared secret from point"); 407 goto fin; 408 } 409 410 /* now do the response */ 411 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 412 data->my_element, x, y, 413 data->bnctx)) { 414 wpa_printf(MSG_INFO, "EAP-PWD (peer): point assignment fail"); 415 goto fin; 416 } 417 418 if (((scalar = os_malloc(BN_num_bytes(data->grp->order))) == NULL) || 419 ((element = os_malloc(BN_num_bytes(data->grp->prime) * 2)) == 420 NULL)) { 421 wpa_printf(MSG_INFO, "EAP-PWD (peer): data allocation fail"); 422 goto fin; 423 } 424 425 /* 426 * bignums occupy as little memory as possible so one that is 427 * sufficiently smaller than the prime or order might need pre-pending 428 * with zeros. 429 */ 430 os_memset(scalar, 0, BN_num_bytes(data->grp->order)); 431 os_memset(element, 0, BN_num_bytes(data->grp->prime) * 2); 432 offset = BN_num_bytes(data->grp->order) - 433 BN_num_bytes(data->my_scalar); 434 BN_bn2bin(data->my_scalar, scalar + offset); 435 436 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 437 BN_bn2bin(x, element + offset); 438 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 439 BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset); 440 441 data->outbuf = wpabuf_alloc(BN_num_bytes(data->grp->order) + 442 2 * BN_num_bytes(data->grp->prime)); 443 if (data->outbuf == NULL) 444 goto fin; 445 446 /* we send the element as (x,y) follwed by the scalar */ 447 wpabuf_put_data(data->outbuf, element, 448 2 * BN_num_bytes(data->grp->prime)); 449 wpabuf_put_data(data->outbuf, scalar, BN_num_bytes(data->grp->order)); 450 451fin: 452 os_free(scalar); 453 os_free(element); 454 BN_free(x); 455 BN_free(y); 456 BN_free(cofactor); 457 EC_POINT_free(K); 458 EC_POINT_free(point); 459 if (data->outbuf == NULL) 460 eap_pwd_state(data, FAILURE); 461 else 462 eap_pwd_state(data, PWD_Confirm_Req); 463} 464 465 466static void 467eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data, 468 struct eap_method_ret *ret, 469 const struct wpabuf *reqData, 470 const u8 *payload, size_t payload_len) 471{ 472 BIGNUM *x = NULL, *y = NULL; 473 struct crypto_hash *hash; 474 u32 cs; 475 u16 grp; 476 u8 conf[SHA256_MAC_LEN], *cruft = NULL, *ptr; 477 int offset; 478 479 /* 480 * first build up the ciphersuite which is group | random_function | 481 * prf 482 */ 483 grp = htons(data->group_num); 484 ptr = (u8 *) &cs; 485 os_memcpy(ptr, &grp, sizeof(u16)); 486 ptr += sizeof(u16); 487 *ptr = EAP_PWD_DEFAULT_RAND_FUNC; 488 ptr += sizeof(u8); 489 *ptr = EAP_PWD_DEFAULT_PRF; 490 491 /* each component of the cruft will be at most as big as the prime */ 492 if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) || 493 ((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) { 494 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm allocation " 495 "fail"); 496 goto fin; 497 } 498 499 /* 500 * server's commit is H(k | server_element | server_scalar | 501 * peer_element | peer_scalar | ciphersuite) 502 */ 503 hash = eap_pwd_h_init(); 504 if (hash == NULL) 505 goto fin; 506 507 /* 508 * zero the memory each time because this is mod prime math and some 509 * value may start with a few zeros and the previous one did not. 510 */ 511 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 512 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k); 513 BN_bn2bin(data->k, cruft + offset); 514 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 515 516 /* server element: x, y */ 517 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 518 data->server_element, x, y, 519 data->bnctx)) { 520 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point " 521 "assignment fail"); 522 goto fin; 523 } 524 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 525 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 526 BN_bn2bin(x, cruft + offset); 527 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 528 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 529 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 530 BN_bn2bin(y, cruft + offset); 531 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 532 533 /* server scalar */ 534 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 535 offset = BN_num_bytes(data->grp->order) - 536 BN_num_bytes(data->server_scalar); 537 BN_bn2bin(data->server_scalar, cruft + offset); 538 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order)); 539 540 /* my element: x, y */ 541 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 542 data->my_element, x, y, 543 data->bnctx)) { 544 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point " 545 "assignment fail"); 546 goto fin; 547 } 548 549 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 550 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 551 BN_bn2bin(x, cruft + offset); 552 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 553 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 554 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 555 BN_bn2bin(y, cruft + offset); 556 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 557 558 /* my scalar */ 559 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 560 offset = BN_num_bytes(data->grp->order) - 561 BN_num_bytes(data->my_scalar); 562 BN_bn2bin(data->my_scalar, cruft + offset); 563 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order)); 564 565 /* the ciphersuite */ 566 eap_pwd_h_update(hash, (u8 *) &cs, sizeof(u32)); 567 568 /* random function fin */ 569 eap_pwd_h_final(hash, conf); 570 571 ptr = (u8 *) payload; 572 if (os_memcmp(conf, ptr, SHA256_MAC_LEN)) { 573 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm did not verify"); 574 goto fin; 575 } 576 577 wpa_printf(MSG_DEBUG, "EAP-pwd (peer): confirm verified"); 578 579 /* 580 * compute confirm: 581 * H(k | peer_element | peer_scalar | server_element | server_scalar | 582 * ciphersuite) 583 */ 584 hash = eap_pwd_h_init(); 585 if (hash == NULL) 586 goto fin; 587 588 /* k */ 589 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 590 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k); 591 BN_bn2bin(data->k, cruft + offset); 592 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 593 594 /* my element */ 595 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 596 data->my_element, x, y, 597 data->bnctx)) { 598 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point " 599 "assignment fail"); 600 goto fin; 601 } 602 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 603 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 604 BN_bn2bin(x, cruft + offset); 605 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 606 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 607 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 608 BN_bn2bin(y, cruft + offset); 609 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 610 611 /* my scalar */ 612 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 613 offset = BN_num_bytes(data->grp->order) - 614 BN_num_bytes(data->my_scalar); 615 BN_bn2bin(data->my_scalar, cruft + offset); 616 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order)); 617 618 /* server element: x, y */ 619 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, 620 data->server_element, x, y, 621 data->bnctx)) { 622 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point " 623 "assignment fail"); 624 goto fin; 625 } 626 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 627 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x); 628 BN_bn2bin(x, cruft + offset); 629 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 630 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 631 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y); 632 BN_bn2bin(y, cruft + offset); 633 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime)); 634 635 /* server scalar */ 636 os_memset(cruft, 0, BN_num_bytes(data->grp->prime)); 637 offset = BN_num_bytes(data->grp->order) - 638 BN_num_bytes(data->server_scalar); 639 BN_bn2bin(data->server_scalar, cruft + offset); 640 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order)); 641 642 /* the ciphersuite */ 643 eap_pwd_h_update(hash, (u8 *) &cs, sizeof(u32)); 644 645 /* all done */ 646 eap_pwd_h_final(hash, conf); 647 648 if (compute_keys(data->grp, data->bnctx, data->k, 649 data->my_scalar, data->server_scalar, conf, ptr, 650 &cs, data->msk, data->emsk) < 0) { 651 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute MSK | " 652 "EMSK"); 653 goto fin; 654 } 655 656 data->outbuf = wpabuf_alloc(SHA256_MAC_LEN); 657 if (data->outbuf == NULL) 658 goto fin; 659 660 wpabuf_put_data(data->outbuf, conf, SHA256_MAC_LEN); 661 662fin: 663 os_free(cruft); 664 BN_free(x); 665 BN_free(y); 666 if (data->outbuf == NULL) { 667 ret->methodState = METHOD_DONE; 668 ret->decision = DECISION_FAIL; 669 eap_pwd_state(data, FAILURE); 670 } else { 671 eap_pwd_state(data, SUCCESS_ON_FRAG_COMPLETION); 672 } 673} 674 675 676static struct wpabuf * 677eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret, 678 const struct wpabuf *reqData) 679{ 680 struct eap_pwd_data *data = priv; 681 struct wpabuf *resp = NULL; 682 const u8 *pos, *buf; 683 size_t len; 684 u16 tot_len = 0; 685 u8 lm_exch; 686 687 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, reqData, &len); 688 if ((pos == NULL) || (len < 1)) { 689 wpa_printf(MSG_DEBUG, "EAP-pwd: Got a frame but pos is %s and " 690 "len is %d", 691 pos == NULL ? "NULL" : "not NULL", (int) len); 692 ret->ignore = TRUE; 693 return NULL; 694 } 695 696 ret->ignore = FALSE; 697 ret->methodState = METHOD_MAY_CONT; 698 ret->decision = DECISION_FAIL; 699 ret->allowNotifications = FALSE; 700 701 lm_exch = *pos; 702 pos++; /* skip over the bits and the exch */ 703 len--; 704 705 /* 706 * we're fragmenting so send out the next fragment 707 */ 708 if (data->out_frag_pos) { 709 /* 710 * this should be an ACK 711 */ 712 if (len) 713 wpa_printf(MSG_INFO, "Bad Response! Fragmenting but " 714 "not an ACK"); 715 716 wpa_printf(MSG_DEBUG, "EAP-pwd: Got an ACK for a fragment"); 717 /* 718 * check if there are going to be more fragments 719 */ 720 len = wpabuf_len(data->outbuf) - data->out_frag_pos; 721 if ((len + EAP_PWD_HDR_SIZE) > data->mtu) { 722 len = data->mtu - EAP_PWD_HDR_SIZE; 723 EAP_PWD_SET_MORE_BIT(lm_exch); 724 } 725 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, 726 EAP_PWD_HDR_SIZE + len, 727 EAP_CODE_RESPONSE, eap_get_id(reqData)); 728 if (resp == NULL) { 729 wpa_printf(MSG_INFO, "Unable to allocate memory for " 730 "next fragment!"); 731 return NULL; 732 } 733 wpabuf_put_u8(resp, lm_exch); 734 buf = wpabuf_head_u8(data->outbuf); 735 wpabuf_put_data(resp, buf + data->out_frag_pos, len); 736 data->out_frag_pos += len; 737 /* 738 * this is the last fragment so get rid of the out buffer 739 */ 740 if (data->out_frag_pos >= wpabuf_len(data->outbuf)) { 741 wpabuf_free(data->outbuf); 742 data->outbuf = NULL; 743 data->out_frag_pos = 0; 744 } 745 wpa_printf(MSG_DEBUG, "EAP-pwd: Send %s fragment of %d bytes", 746 data->out_frag_pos == 0 ? "last" : "next", 747 (int) len); 748 if (data->state == SUCCESS_ON_FRAG_COMPLETION) { 749 ret->methodState = METHOD_DONE; 750 ret->decision = DECISION_UNCOND_SUCC; 751 eap_pwd_state(data, SUCCESS); 752 } 753 return resp; 754 } 755 756 /* 757 * see if this is a fragment that needs buffering 758 * 759 * if it's the first fragment there'll be a length field 760 */ 761 if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) { 762 tot_len = WPA_GET_BE16(pos); 763 wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments whose " 764 "total length = %d", tot_len); 765 data->inbuf = wpabuf_alloc(tot_len); 766 if (data->inbuf == NULL) { 767 wpa_printf(MSG_INFO, "Out of memory to buffer " 768 "fragments!"); 769 return NULL; 770 } 771 pos += sizeof(u16); 772 len -= sizeof(u16); 773 } 774 /* 775 * buffer and ACK the fragment 776 */ 777 if (EAP_PWD_GET_MORE_BIT(lm_exch)) { 778 data->in_frag_pos += len; 779 if (data->in_frag_pos > wpabuf_size(data->inbuf)) { 780 wpa_printf(MSG_INFO, "EAP-pwd: Buffer overflow attack " 781 "detected (%d vs. %d)!", 782 (int) data->in_frag_pos, 783 (int) wpabuf_len(data->inbuf)); 784 wpabuf_free(data->inbuf); 785 data->inbuf = NULL; 786 data->in_frag_pos = 0; 787 return NULL; 788 } 789 wpabuf_put_data(data->inbuf, pos, len); 790 791 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, 792 EAP_PWD_HDR_SIZE, 793 EAP_CODE_RESPONSE, eap_get_id(reqData)); 794 if (resp != NULL) 795 wpabuf_put_u8(resp, (EAP_PWD_GET_EXCHANGE(lm_exch))); 796 wpa_printf(MSG_DEBUG, "EAP-pwd: ACKing a %d byte fragment", 797 (int) len); 798 return resp; 799 } 800 /* 801 * we're buffering and this is the last fragment 802 */ 803 if (data->in_frag_pos) { 804 wpabuf_put_data(data->inbuf, pos, len); 805 wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes", 806 (int) len); 807 data->in_frag_pos += len; 808 pos = wpabuf_head_u8(data->inbuf); 809 len = data->in_frag_pos; 810 } 811 wpa_printf(MSG_DEBUG, "EAP-pwd: processing frame: exch %d, len %d", 812 EAP_PWD_GET_EXCHANGE(lm_exch), (int) len); 813 814 switch (EAP_PWD_GET_EXCHANGE(lm_exch)) { 815 case EAP_PWD_OPCODE_ID_EXCH: 816 eap_pwd_perform_id_exchange(sm, data, ret, reqData, 817 pos, len); 818 break; 819 case EAP_PWD_OPCODE_COMMIT_EXCH: 820 eap_pwd_perform_commit_exchange(sm, data, ret, reqData, 821 pos, len); 822 break; 823 case EAP_PWD_OPCODE_CONFIRM_EXCH: 824 eap_pwd_perform_confirm_exchange(sm, data, ret, reqData, 825 pos, len); 826 break; 827 default: 828 wpa_printf(MSG_INFO, "EAP-pwd: Ignoring message with unknown " 829 "opcode %d", lm_exch); 830 break; 831 } 832 /* 833 * if we buffered the just processed input now's the time to free it 834 */ 835 if (data->in_frag_pos) { 836 wpabuf_free(data->inbuf); 837 data->inbuf = NULL; 838 data->in_frag_pos = 0; 839 } 840 841 if (data->outbuf == NULL) 842 return NULL; /* generic failure */ 843 844 /* 845 * we have output! Do we need to fragment it? 846 */ 847 len = wpabuf_len(data->outbuf); 848 if ((len + EAP_PWD_HDR_SIZE) > data->mtu) { 849 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, data->mtu, 850 EAP_CODE_RESPONSE, eap_get_id(reqData)); 851 /* 852 * if so it's the first so include a length field 853 */ 854 EAP_PWD_SET_LENGTH_BIT(lm_exch); 855 EAP_PWD_SET_MORE_BIT(lm_exch); 856 tot_len = len; 857 /* 858 * keep the packet at the MTU 859 */ 860 len = data->mtu - EAP_PWD_HDR_SIZE - sizeof(u16); 861 wpa_printf(MSG_DEBUG, "EAP-pwd: Fragmenting output, total " 862 "length = %d", tot_len); 863 } else { 864 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, 865 EAP_PWD_HDR_SIZE + len, 866 EAP_CODE_RESPONSE, eap_get_id(reqData)); 867 } 868 if (resp == NULL) 869 return NULL; 870 871 wpabuf_put_u8(resp, lm_exch); 872 if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) { 873 wpabuf_put_be16(resp, tot_len); 874 data->out_frag_pos += len; 875 } 876 buf = wpabuf_head_u8(data->outbuf); 877 wpabuf_put_data(resp, buf, len); 878 /* 879 * if we're not fragmenting then there's no need to carry this around 880 */ 881 if (data->out_frag_pos == 0) { 882 wpabuf_free(data->outbuf); 883 data->outbuf = NULL; 884 data->out_frag_pos = 0; 885 if (data->state == SUCCESS_ON_FRAG_COMPLETION) { 886 ret->methodState = METHOD_DONE; 887 ret->decision = DECISION_UNCOND_SUCC; 888 eap_pwd_state(data, SUCCESS); 889 } 890 } 891 892 return resp; 893} 894 895 896static Boolean eap_pwd_key_available(struct eap_sm *sm, void *priv) 897{ 898 struct eap_pwd_data *data = priv; 899 return data->state == SUCCESS; 900} 901 902 903static u8 * eap_pwd_get_emsk(struct eap_sm *sm, void *priv, size_t *len) 904{ 905 struct eap_pwd_data *data = priv; 906 u8 *key; 907 908 if (data->state != SUCCESS) 909 return NULL; 910 911 if ((key = os_malloc(EAP_EMSK_LEN)) == NULL) 912 return NULL; 913 914 os_memcpy(key, data->emsk, EAP_EMSK_LEN); 915 *len = EAP_EMSK_LEN; 916 917 return key; 918} 919 920 921int eap_peer_pwd_register(void) 922{ 923 struct eap_method *eap; 924 int ret; 925 926 EVP_add_digest(EVP_sha256()); 927 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION, 928 EAP_VENDOR_IETF, EAP_TYPE_PWD, "PWD"); 929 if (eap == NULL) 930 return -1; 931 932 eap->init = eap_pwd_init; 933 eap->deinit = eap_pwd_deinit; 934 eap->process = eap_pwd_process; 935 eap->isKeyAvailable = eap_pwd_key_available; 936 eap->getKey = eap_pwd_getkey; 937 eap->get_emsk = eap_pwd_get_emsk; 938 939 ret = eap_peer_method_register(eap); 940 if (ret) 941 eap_peer_method_free(eap); 942 return ret; 943} 944