1 /* 2 * Simultaneous authentication of equals 3 * Copyright (c) 2012-2016, 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 9 #include "includes.h" 10 11 #include "common.h" 12 #include "crypto/crypto.h" 13 #include "crypto/sha256.h" 14 #include "crypto/random.h" 15 #include "crypto/dh_groups.h" 16 #include "ieee802_11_defs.h" 17 #include "sae.h" 18 19 20 int sae_set_group(struct sae_data *sae, int group) 21 { 22 struct sae_temporary_data *tmp; 23 24 sae_clear_data(sae); 25 tmp = sae->tmp = os_zalloc(sizeof(*tmp)); 26 if (tmp == NULL) 27 return -1; 28 29 /* First, check if this is an ECC group */ 30 tmp->ec = crypto_ec_init(group); 31 if (tmp->ec) { 32 sae->group = group; 33 tmp->prime_len = crypto_ec_prime_len(tmp->ec); 34 tmp->prime = crypto_ec_get_prime(tmp->ec); 35 tmp->order = crypto_ec_get_order(tmp->ec); 36 return 0; 37 } 38 39 /* Not an ECC group, check FFC */ 40 tmp->dh = dh_groups_get(group); 41 if (tmp->dh) { 42 sae->group = group; 43 tmp->prime_len = tmp->dh->prime_len; 44 if (tmp->prime_len > SAE_MAX_PRIME_LEN) { 45 sae_clear_data(sae); 46 return -1; 47 } 48 49 tmp->prime_buf = crypto_bignum_init_set(tmp->dh->prime, 50 tmp->prime_len); 51 if (tmp->prime_buf == NULL) { 52 sae_clear_data(sae); 53 return -1; 54 } 55 tmp->prime = tmp->prime_buf; 56 57 tmp->order_buf = crypto_bignum_init_set(tmp->dh->order, 58 tmp->dh->order_len); 59 if (tmp->order_buf == NULL) { 60 sae_clear_data(sae); 61 return -1; 62 } 63 tmp->order = tmp->order_buf; 64 65 return 0; 66 } 67 68 /* Unsupported group */ 69 return -1; 70 } 71 72 73 void sae_clear_temp_data(struct sae_data *sae) 74 { 75 struct sae_temporary_data *tmp; 76 if (sae == NULL || sae->tmp == NULL) 77 return; 78 tmp = sae->tmp; 79 crypto_ec_deinit(tmp->ec); 80 crypto_bignum_deinit(tmp->prime_buf, 0); 81 crypto_bignum_deinit(tmp->order_buf, 0); 82 crypto_bignum_deinit(tmp->sae_rand, 1); 83 crypto_bignum_deinit(tmp->pwe_ffc, 1); 84 crypto_bignum_deinit(tmp->own_commit_scalar, 0); 85 crypto_bignum_deinit(tmp->own_commit_element_ffc, 0); 86 crypto_bignum_deinit(tmp->peer_commit_element_ffc, 0); 87 crypto_ec_point_deinit(tmp->pwe_ecc, 1); 88 crypto_ec_point_deinit(tmp->own_commit_element_ecc, 0); 89 crypto_ec_point_deinit(tmp->peer_commit_element_ecc, 0); 90 wpabuf_free(tmp->anti_clogging_token); 91 bin_clear_free(tmp, sizeof(*tmp)); 92 sae->tmp = NULL; 93 } 94 95 96 void sae_clear_data(struct sae_data *sae) 97 { 98 if (sae == NULL) 99 return; 100 sae_clear_temp_data(sae); 101 crypto_bignum_deinit(sae->peer_commit_scalar, 0); 102 os_memset(sae, 0, sizeof(*sae)); 103 } 104 105 106 static void buf_shift_right(u8 *buf, size_t len, size_t bits) 107 { 108 size_t i; 109 for (i = len - 1; i > 0; i--) 110 buf[i] = (buf[i - 1] << (8 - bits)) | (buf[i] >> bits); 111 buf[0] >>= bits; 112 } 113 114 115 static struct crypto_bignum * sae_get_rand(struct sae_data *sae) 116 { 117 u8 val[SAE_MAX_PRIME_LEN]; 118 int iter = 0; 119 struct crypto_bignum *bn = NULL; 120 int order_len_bits = crypto_bignum_bits(sae->tmp->order); 121 size_t order_len = (order_len_bits + 7) / 8; 122 123 if (order_len > sizeof(val)) 124 return NULL; 125 126 for (;;) { 127 if (iter++ > 100 || random_get_bytes(val, order_len) < 0) 128 return NULL; 129 if (order_len_bits % 8) 130 buf_shift_right(val, order_len, 8 - order_len_bits % 8); 131 bn = crypto_bignum_init_set(val, order_len); 132 if (bn == NULL) 133 return NULL; 134 if (crypto_bignum_is_zero(bn) || 135 crypto_bignum_is_one(bn) || 136 crypto_bignum_cmp(bn, sae->tmp->order) >= 0) { 137 crypto_bignum_deinit(bn, 0); 138 continue; 139 } 140 break; 141 } 142 143 os_memset(val, 0, order_len); 144 return bn; 145 } 146 147 148 static struct crypto_bignum * sae_get_rand_and_mask(struct sae_data *sae) 149 { 150 crypto_bignum_deinit(sae->tmp->sae_rand, 1); 151 sae->tmp->sae_rand = sae_get_rand(sae); 152 if (sae->tmp->sae_rand == NULL) 153 return NULL; 154 return sae_get_rand(sae); 155 } 156 157 158 static void sae_pwd_seed_key(const u8 *addr1, const u8 *addr2, u8 *key) 159 { 160 wpa_printf(MSG_DEBUG, "SAE: PWE derivation - addr1=" MACSTR 161 " addr2=" MACSTR, MAC2STR(addr1), MAC2STR(addr2)); 162 if (os_memcmp(addr1, addr2, ETH_ALEN) > 0) { 163 os_memcpy(key, addr1, ETH_ALEN); 164 os_memcpy(key + ETH_ALEN, addr2, ETH_ALEN); 165 } else { 166 os_memcpy(key, addr2, ETH_ALEN); 167 os_memcpy(key + ETH_ALEN, addr1, ETH_ALEN); 168 } 169 } 170 171 172 static struct crypto_bignum * 173 get_rand_1_to_p_1(const u8 *prime, size_t prime_len, size_t prime_bits, 174 int *r_odd) 175 { 176 for (;;) { 177 struct crypto_bignum *r; 178 u8 tmp[SAE_MAX_ECC_PRIME_LEN]; 179 180 if (random_get_bytes(tmp, prime_len) < 0) 181 break; 182 if (prime_bits % 8) 183 buf_shift_right(tmp, prime_len, 8 - prime_bits % 8); 184 if (os_memcmp(tmp, prime, prime_len) >= 0) 185 continue; 186 r = crypto_bignum_init_set(tmp, prime_len); 187 if (!r) 188 break; 189 if (crypto_bignum_is_zero(r)) { 190 crypto_bignum_deinit(r, 0); 191 continue; 192 } 193 194 *r_odd = tmp[prime_len - 1] & 0x01; 195 return r; 196 } 197 198 return NULL; 199 } 200 201 202 static int is_quadratic_residue_blind(struct sae_data *sae, 203 const u8 *prime, size_t bits, 204 const struct crypto_bignum *qr, 205 const struct crypto_bignum *qnr, 206 const struct crypto_bignum *y_sqr) 207 { 208 struct crypto_bignum *r, *num; 209 int r_odd, check, res = -1; 210 211 /* 212 * Use the blinding technique to mask y_sqr while determining 213 * whether it is a quadratic residue modulo p to avoid leaking 214 * timing information while determining the Legendre symbol. 215 * 216 * v = y_sqr 217 * r = a random number between 1 and p-1, inclusive 218 * num = (v * r * r) modulo p 219 */ 220 r = get_rand_1_to_p_1(prime, sae->tmp->prime_len, bits, &r_odd); 221 if (!r) 222 return -1; 223 224 num = crypto_bignum_init(); 225 if (!num || 226 crypto_bignum_mulmod(y_sqr, r, sae->tmp->prime, num) < 0 || 227 crypto_bignum_mulmod(num, r, sae->tmp->prime, num) < 0) 228 goto fail; 229 230 if (r_odd) { 231 /* 232 * num = (num * qr) module p 233 * LGR(num, p) = 1 ==> quadratic residue 234 */ 235 if (crypto_bignum_mulmod(num, qr, sae->tmp->prime, num) < 0) 236 goto fail; 237 check = 1; 238 } else { 239 /* 240 * num = (num * qnr) module p 241 * LGR(num, p) = -1 ==> quadratic residue 242 */ 243 if (crypto_bignum_mulmod(num, qnr, sae->tmp->prime, num) < 0) 244 goto fail; 245 check = -1; 246 } 247 248 res = crypto_bignum_legendre(num, sae->tmp->prime); 249 if (res == -2) { 250 res = -1; 251 goto fail; 252 } 253 res = res == check; 254 fail: 255 crypto_bignum_deinit(num, 1); 256 crypto_bignum_deinit(r, 1); 257 return res; 258 } 259 260 261 static int sae_test_pwd_seed_ecc(struct sae_data *sae, const u8 *pwd_seed, 262 const u8 *prime, 263 const struct crypto_bignum *qr, 264 const struct crypto_bignum *qnr, 265 struct crypto_bignum **ret_x_cand) 266 { 267 u8 pwd_value[SAE_MAX_ECC_PRIME_LEN]; 268 struct crypto_bignum *y_sqr, *x_cand; 269 int res; 270 size_t bits; 271 272 *ret_x_cand = NULL; 273 274 wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN); 275 276 /* pwd-value = KDF-z(pwd-seed, "SAE Hunting and Pecking", p) */ 277 bits = crypto_ec_prime_len_bits(sae->tmp->ec); 278 if (sha256_prf_bits(pwd_seed, SHA256_MAC_LEN, "SAE Hunting and Pecking", 279 prime, sae->tmp->prime_len, pwd_value, bits) < 0) 280 return -1; 281 if (bits % 8) 282 buf_shift_right(pwd_value, sizeof(pwd_value), 8 - bits % 8); 283 wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value", 284 pwd_value, sae->tmp->prime_len); 285 286 if (os_memcmp(pwd_value, prime, sae->tmp->prime_len) >= 0) 287 return 0; 288 289 x_cand = crypto_bignum_init_set(pwd_value, sae->tmp->prime_len); 290 if (!x_cand) 291 return -1; 292 y_sqr = crypto_ec_point_compute_y_sqr(sae->tmp->ec, x_cand); 293 if (!y_sqr) { 294 crypto_bignum_deinit(x_cand, 1); 295 return -1; 296 } 297 298 res = is_quadratic_residue_blind(sae, prime, bits, qr, qnr, y_sqr); 299 crypto_bignum_deinit(y_sqr, 1); 300 if (res <= 0) { 301 crypto_bignum_deinit(x_cand, 1); 302 return res; 303 } 304 305 *ret_x_cand = x_cand; 306 return 1; 307 } 308 309 310 static int sae_test_pwd_seed_ffc(struct sae_data *sae, const u8 *pwd_seed, 311 struct crypto_bignum *pwe) 312 { 313 u8 pwd_value[SAE_MAX_PRIME_LEN]; 314 size_t bits = sae->tmp->prime_len * 8; 315 u8 exp[1]; 316 struct crypto_bignum *a, *b; 317 int res; 318 319 wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN); 320 321 /* pwd-value = KDF-z(pwd-seed, "SAE Hunting and Pecking", p) */ 322 if (sha256_prf_bits(pwd_seed, SHA256_MAC_LEN, "SAE Hunting and Pecking", 323 sae->tmp->dh->prime, sae->tmp->prime_len, pwd_value, 324 bits) < 0) 325 return -1; 326 wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value", pwd_value, 327 sae->tmp->prime_len); 328 329 if (os_memcmp(pwd_value, sae->tmp->dh->prime, sae->tmp->prime_len) >= 0) 330 { 331 wpa_printf(MSG_DEBUG, "SAE: pwd-value >= p"); 332 return 0; 333 } 334 335 /* PWE = pwd-value^((p-1)/r) modulo p */ 336 337 a = crypto_bignum_init_set(pwd_value, sae->tmp->prime_len); 338 339 if (sae->tmp->dh->safe_prime) { 340 /* 341 * r = (p-1)/2 for the group used here, so this becomes: 342 * PWE = pwd-value^2 modulo p 343 */ 344 exp[0] = 2; 345 b = crypto_bignum_init_set(exp, sizeof(exp)); 346 } else { 347 /* Calculate exponent: (p-1)/r */ 348 exp[0] = 1; 349 b = crypto_bignum_init_set(exp, sizeof(exp)); 350 if (b == NULL || 351 crypto_bignum_sub(sae->tmp->prime, b, b) < 0 || 352 crypto_bignum_div(b, sae->tmp->order, b) < 0) { 353 crypto_bignum_deinit(b, 0); 354 b = NULL; 355 } 356 } 357 358 if (a == NULL || b == NULL) 359 res = -1; 360 else 361 res = crypto_bignum_exptmod(a, b, sae->tmp->prime, pwe); 362 363 crypto_bignum_deinit(a, 0); 364 crypto_bignum_deinit(b, 0); 365 366 if (res < 0) { 367 wpa_printf(MSG_DEBUG, "SAE: Failed to calculate PWE"); 368 return -1; 369 } 370 371 /* if (PWE > 1) --> found */ 372 if (crypto_bignum_is_zero(pwe) || crypto_bignum_is_one(pwe)) { 373 wpa_printf(MSG_DEBUG, "SAE: PWE <= 1"); 374 return 0; 375 } 376 377 wpa_printf(MSG_DEBUG, "SAE: PWE found"); 378 return 1; 379 } 380 381 382 static int get_random_qr_qnr(const u8 *prime, size_t prime_len, 383 const struct crypto_bignum *prime_bn, 384 size_t prime_bits, struct crypto_bignum **qr, 385 struct crypto_bignum **qnr) 386 { 387 *qr = NULL; 388 *qnr = NULL; 389 390 while (!(*qr) || !(*qnr)) { 391 u8 tmp[SAE_MAX_ECC_PRIME_LEN]; 392 struct crypto_bignum *q; 393 int res; 394 395 if (random_get_bytes(tmp, prime_len) < 0) 396 break; 397 if (prime_bits % 8) 398 buf_shift_right(tmp, prime_len, 8 - prime_bits % 8); 399 if (os_memcmp(tmp, prime, prime_len) >= 0) 400 continue; 401 q = crypto_bignum_init_set(tmp, prime_len); 402 if (!q) 403 break; 404 res = crypto_bignum_legendre(q, prime_bn); 405 406 if (res == 1 && !(*qr)) 407 *qr = q; 408 else if (res == -1 && !(*qnr)) 409 *qnr = q; 410 else 411 crypto_bignum_deinit(q, 0); 412 } 413 414 return (*qr && *qnr) ? 0 : -1; 415 } 416 417 418 static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1, 419 const u8 *addr2, const u8 *password, 420 size_t password_len) 421 { 422 u8 counter, k = 40; 423 u8 addrs[2 * ETH_ALEN]; 424 const u8 *addr[2]; 425 size_t len[2]; 426 u8 dummy_password[32]; 427 size_t dummy_password_len; 428 int pwd_seed_odd = 0; 429 u8 prime[SAE_MAX_ECC_PRIME_LEN]; 430 size_t prime_len; 431 struct crypto_bignum *x = NULL, *qr, *qnr; 432 size_t bits; 433 int res; 434 435 dummy_password_len = password_len; 436 if (dummy_password_len > sizeof(dummy_password)) 437 dummy_password_len = sizeof(dummy_password); 438 if (random_get_bytes(dummy_password, dummy_password_len) < 0) 439 return -1; 440 441 prime_len = sae->tmp->prime_len; 442 if (crypto_bignum_to_bin(sae->tmp->prime, prime, sizeof(prime), 443 prime_len) < 0) 444 return -1; 445 bits = crypto_ec_prime_len_bits(sae->tmp->ec); 446 447 /* 448 * Create a random quadratic residue (qr) and quadratic non-residue 449 * (qnr) modulo p for blinding purposes during the loop. 450 */ 451 if (get_random_qr_qnr(prime, prime_len, sae->tmp->prime, bits, 452 &qr, &qnr) < 0) 453 return -1; 454 455 wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password", 456 password, password_len); 457 458 /* 459 * H(salt, ikm) = HMAC-SHA256(salt, ikm) 460 * base = password 461 * pwd-seed = H(MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC), 462 * base || counter) 463 */ 464 sae_pwd_seed_key(addr1, addr2, addrs); 465 466 addr[0] = password; 467 len[0] = password_len; 468 addr[1] = &counter; 469 len[1] = sizeof(counter); 470 471 /* 472 * Continue for at least k iterations to protect against side-channel 473 * attacks that attempt to determine the number of iterations required 474 * in the loop. 475 */ 476 for (counter = 1; counter <= k || !x; counter++) { 477 u8 pwd_seed[SHA256_MAC_LEN]; 478 struct crypto_bignum *x_cand; 479 480 if (counter > 200) { 481 /* This should not happen in practice */ 482 wpa_printf(MSG_DEBUG, "SAE: Failed to derive PWE"); 483 break; 484 } 485 486 wpa_printf(MSG_DEBUG, "SAE: counter = %u", counter); 487 if (hmac_sha256_vector(addrs, sizeof(addrs), 2, addr, len, 488 pwd_seed) < 0) 489 break; 490 491 res = sae_test_pwd_seed_ecc(sae, pwd_seed, 492 prime, qr, qnr, &x_cand); 493 if (res < 0) 494 goto fail; 495 if (res > 0 && !x) { 496 wpa_printf(MSG_DEBUG, 497 "SAE: Selected pwd-seed with counter %u", 498 counter); 499 x = x_cand; 500 pwd_seed_odd = pwd_seed[SHA256_MAC_LEN - 1] & 0x01; 501 os_memset(pwd_seed, 0, sizeof(pwd_seed)); 502 503 /* 504 * Use a dummy password for the following rounds, if 505 * any. 506 */ 507 addr[0] = dummy_password; 508 len[0] = dummy_password_len; 509 } else if (res > 0) { 510 crypto_bignum_deinit(x_cand, 1); 511 } 512 } 513 514 if (!x) { 515 wpa_printf(MSG_DEBUG, "SAE: Could not generate PWE"); 516 res = -1; 517 goto fail; 518 } 519 520 if (!sae->tmp->pwe_ecc) 521 sae->tmp->pwe_ecc = crypto_ec_point_init(sae->tmp->ec); 522 if (!sae->tmp->pwe_ecc) 523 res = -1; 524 else 525 res = crypto_ec_point_solve_y_coord(sae->tmp->ec, 526 sae->tmp->pwe_ecc, x, 527 pwd_seed_odd); 528 crypto_bignum_deinit(x, 1); 529 if (res < 0) { 530 /* 531 * This should not happen since we already checked that there 532 * is a result. 533 */ 534 wpa_printf(MSG_DEBUG, "SAE: Could not solve y"); 535 } 536 537 fail: 538 crypto_bignum_deinit(qr, 0); 539 crypto_bignum_deinit(qnr, 0); 540 541 return res; 542 } 543 544 545 static int sae_derive_pwe_ffc(struct sae_data *sae, const u8 *addr1, 546 const u8 *addr2, const u8 *password, 547 size_t password_len) 548 { 549 u8 counter; 550 u8 addrs[2 * ETH_ALEN]; 551 const u8 *addr[2]; 552 size_t len[2]; 553 int found = 0; 554 555 if (sae->tmp->pwe_ffc == NULL) { 556 sae->tmp->pwe_ffc = crypto_bignum_init(); 557 if (sae->tmp->pwe_ffc == NULL) 558 return -1; 559 } 560 561 wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password", 562 password, password_len); 563 564 /* 565 * H(salt, ikm) = HMAC-SHA256(salt, ikm) 566 * pwd-seed = H(MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC), 567 * password || counter) 568 */ 569 sae_pwd_seed_key(addr1, addr2, addrs); 570 571 addr[0] = password; 572 len[0] = password_len; 573 addr[1] = &counter; 574 len[1] = sizeof(counter); 575 576 for (counter = 1; !found; counter++) { 577 u8 pwd_seed[SHA256_MAC_LEN]; 578 int res; 579 580 if (counter > 200) { 581 /* This should not happen in practice */ 582 wpa_printf(MSG_DEBUG, "SAE: Failed to derive PWE"); 583 break; 584 } 585 586 wpa_printf(MSG_DEBUG, "SAE: counter = %u", counter); 587 if (hmac_sha256_vector(addrs, sizeof(addrs), 2, addr, len, 588 pwd_seed) < 0) 589 break; 590 res = sae_test_pwd_seed_ffc(sae, pwd_seed, sae->tmp->pwe_ffc); 591 if (res < 0) 592 break; 593 if (res > 0) { 594 wpa_printf(MSG_DEBUG, "SAE: Use this PWE"); 595 found = 1; 596 } 597 } 598 599 return found ? 0 : -1; 600 } 601 602 603 static int sae_derive_commit_element_ecc(struct sae_data *sae, 604 struct crypto_bignum *mask) 605 { 606 /* COMMIT-ELEMENT = inverse(scalar-op(mask, PWE)) */ 607 if (!sae->tmp->own_commit_element_ecc) { 608 sae->tmp->own_commit_element_ecc = 609 crypto_ec_point_init(sae->tmp->ec); 610 if (!sae->tmp->own_commit_element_ecc) 611 return -1; 612 } 613 614 if (crypto_ec_point_mul(sae->tmp->ec, sae->tmp->pwe_ecc, mask, 615 sae->tmp->own_commit_element_ecc) < 0 || 616 crypto_ec_point_invert(sae->tmp->ec, 617 sae->tmp->own_commit_element_ecc) < 0) { 618 wpa_printf(MSG_DEBUG, "SAE: Could not compute commit-element"); 619 return -1; 620 } 621 622 return 0; 623 } 624 625 626 static int sae_derive_commit_element_ffc(struct sae_data *sae, 627 struct crypto_bignum *mask) 628 { 629 /* COMMIT-ELEMENT = inverse(scalar-op(mask, PWE)) */ 630 if (!sae->tmp->own_commit_element_ffc) { 631 sae->tmp->own_commit_element_ffc = crypto_bignum_init(); 632 if (!sae->tmp->own_commit_element_ffc) 633 return -1; 634 } 635 636 if (crypto_bignum_exptmod(sae->tmp->pwe_ffc, mask, sae->tmp->prime, 637 sae->tmp->own_commit_element_ffc) < 0 || 638 crypto_bignum_inverse(sae->tmp->own_commit_element_ffc, 639 sae->tmp->prime, 640 sae->tmp->own_commit_element_ffc) < 0) { 641 wpa_printf(MSG_DEBUG, "SAE: Could not compute commit-element"); 642 return -1; 643 } 644 645 return 0; 646 } 647 648 649 static int sae_derive_commit(struct sae_data *sae) 650 { 651 struct crypto_bignum *mask; 652 int ret = -1; 653 unsigned int counter = 0; 654 655 do { 656 counter++; 657 if (counter > 100) { 658 /* 659 * This cannot really happen in practice if the random 660 * number generator is working. Anyway, to avoid even a 661 * theoretical infinite loop, break out after 100 662 * attemps. 663 */ 664 return -1; 665 } 666 667 mask = sae_get_rand_and_mask(sae); 668 if (mask == NULL) { 669 wpa_printf(MSG_DEBUG, "SAE: Could not get rand/mask"); 670 return -1; 671 } 672 673 /* commit-scalar = (rand + mask) modulo r */ 674 if (!sae->tmp->own_commit_scalar) { 675 sae->tmp->own_commit_scalar = crypto_bignum_init(); 676 if (!sae->tmp->own_commit_scalar) 677 goto fail; 678 } 679 crypto_bignum_add(sae->tmp->sae_rand, mask, 680 sae->tmp->own_commit_scalar); 681 crypto_bignum_mod(sae->tmp->own_commit_scalar, sae->tmp->order, 682 sae->tmp->own_commit_scalar); 683 } while (crypto_bignum_is_zero(sae->tmp->own_commit_scalar) || 684 crypto_bignum_is_one(sae->tmp->own_commit_scalar)); 685 686 if ((sae->tmp->ec && sae_derive_commit_element_ecc(sae, mask) < 0) || 687 (sae->tmp->dh && sae_derive_commit_element_ffc(sae, mask) < 0)) 688 goto fail; 689 690 ret = 0; 691 fail: 692 crypto_bignum_deinit(mask, 1); 693 return ret; 694 } 695 696 697 int sae_prepare_commit(const u8 *addr1, const u8 *addr2, 698 const u8 *password, size_t password_len, 699 struct sae_data *sae) 700 { 701 if (sae->tmp == NULL || 702 (sae->tmp->ec && sae_derive_pwe_ecc(sae, addr1, addr2, password, 703 password_len) < 0) || 704 (sae->tmp->dh && sae_derive_pwe_ffc(sae, addr1, addr2, password, 705 password_len) < 0) || 706 sae_derive_commit(sae) < 0) 707 return -1; 708 return 0; 709 } 710 711 712 static int sae_derive_k_ecc(struct sae_data *sae, u8 *k) 713 { 714 struct crypto_ec_point *K; 715 int ret = -1; 716 717 K = crypto_ec_point_init(sae->tmp->ec); 718 if (K == NULL) 719 goto fail; 720 721 /* 722 * K = scalar-op(rand, (elem-op(scalar-op(peer-commit-scalar, PWE), 723 * PEER-COMMIT-ELEMENT))) 724 * If K is identity element (point-at-infinity), reject 725 * k = F(K) (= x coordinate) 726 */ 727 728 if (crypto_ec_point_mul(sae->tmp->ec, sae->tmp->pwe_ecc, 729 sae->peer_commit_scalar, K) < 0 || 730 crypto_ec_point_add(sae->tmp->ec, K, 731 sae->tmp->peer_commit_element_ecc, K) < 0 || 732 crypto_ec_point_mul(sae->tmp->ec, K, sae->tmp->sae_rand, K) < 0 || 733 crypto_ec_point_is_at_infinity(sae->tmp->ec, K) || 734 crypto_ec_point_to_bin(sae->tmp->ec, K, k, NULL) < 0) { 735 wpa_printf(MSG_DEBUG, "SAE: Failed to calculate K and k"); 736 goto fail; 737 } 738 739 wpa_hexdump_key(MSG_DEBUG, "SAE: k", k, sae->tmp->prime_len); 740 741 ret = 0; 742 fail: 743 crypto_ec_point_deinit(K, 1); 744 return ret; 745 } 746 747 748 static int sae_derive_k_ffc(struct sae_data *sae, u8 *k) 749 { 750 struct crypto_bignum *K; 751 int ret = -1; 752 753 K = crypto_bignum_init(); 754 if (K == NULL) 755 goto fail; 756 757 /* 758 * K = scalar-op(rand, (elem-op(scalar-op(peer-commit-scalar, PWE), 759 * PEER-COMMIT-ELEMENT))) 760 * If K is identity element (one), reject. 761 * k = F(K) (= x coordinate) 762 */ 763 764 if (crypto_bignum_exptmod(sae->tmp->pwe_ffc, sae->peer_commit_scalar, 765 sae->tmp->prime, K) < 0 || 766 crypto_bignum_mulmod(K, sae->tmp->peer_commit_element_ffc, 767 sae->tmp->prime, K) < 0 || 768 crypto_bignum_exptmod(K, sae->tmp->sae_rand, sae->tmp->prime, K) < 0 769 || 770 crypto_bignum_is_one(K) || 771 crypto_bignum_to_bin(K, k, SAE_MAX_PRIME_LEN, sae->tmp->prime_len) < 772 0) { 773 wpa_printf(MSG_DEBUG, "SAE: Failed to calculate K and k"); 774 goto fail; 775 } 776 777 wpa_hexdump_key(MSG_DEBUG, "SAE: k", k, sae->tmp->prime_len); 778 779 ret = 0; 780 fail: 781 crypto_bignum_deinit(K, 1); 782 return ret; 783 } 784 785 786 static int sae_derive_keys(struct sae_data *sae, const u8 *k) 787 { 788 u8 null_key[SAE_KEYSEED_KEY_LEN], val[SAE_MAX_PRIME_LEN]; 789 u8 keyseed[SHA256_MAC_LEN]; 790 u8 keys[SAE_KCK_LEN + SAE_PMK_LEN]; 791 struct crypto_bignum *tmp; 792 int ret = -1; 793 794 tmp = crypto_bignum_init(); 795 if (tmp == NULL) 796 goto fail; 797 798 /* keyseed = H(<0>32, k) 799 * KCK || PMK = KDF-512(keyseed, "SAE KCK and PMK", 800 * (commit-scalar + peer-commit-scalar) modulo r) 801 * PMKID = L((commit-scalar + peer-commit-scalar) modulo r, 0, 128) 802 */ 803 804 os_memset(null_key, 0, sizeof(null_key)); 805 hmac_sha256(null_key, sizeof(null_key), k, sae->tmp->prime_len, 806 keyseed); 807 wpa_hexdump_key(MSG_DEBUG, "SAE: keyseed", keyseed, sizeof(keyseed)); 808 809 crypto_bignum_add(sae->tmp->own_commit_scalar, sae->peer_commit_scalar, 810 tmp); 811 crypto_bignum_mod(tmp, sae->tmp->order, tmp); 812 crypto_bignum_to_bin(tmp, val, sizeof(val), sae->tmp->prime_len); 813 wpa_hexdump(MSG_DEBUG, "SAE: PMKID", val, SAE_PMKID_LEN); 814 if (sha256_prf(keyseed, sizeof(keyseed), "SAE KCK and PMK", 815 val, sae->tmp->prime_len, keys, sizeof(keys)) < 0) 816 goto fail; 817 os_memset(keyseed, 0, sizeof(keyseed)); 818 os_memcpy(sae->tmp->kck, keys, SAE_KCK_LEN); 819 os_memcpy(sae->pmk, keys + SAE_KCK_LEN, SAE_PMK_LEN); 820 os_memcpy(sae->pmkid, val, SAE_PMKID_LEN); 821 os_memset(keys, 0, sizeof(keys)); 822 wpa_hexdump_key(MSG_DEBUG, "SAE: KCK", sae->tmp->kck, SAE_KCK_LEN); 823 wpa_hexdump_key(MSG_DEBUG, "SAE: PMK", sae->pmk, SAE_PMK_LEN); 824 825 ret = 0; 826 fail: 827 crypto_bignum_deinit(tmp, 0); 828 return ret; 829 } 830 831 832 int sae_process_commit(struct sae_data *sae) 833 { 834 u8 k[SAE_MAX_PRIME_LEN]; 835 if (sae->tmp == NULL || 836 (sae->tmp->ec && sae_derive_k_ecc(sae, k) < 0) || 837 (sae->tmp->dh && sae_derive_k_ffc(sae, k) < 0) || 838 sae_derive_keys(sae, k) < 0) 839 return -1; 840 return 0; 841 } 842 843 844 void sae_write_commit(struct sae_data *sae, struct wpabuf *buf, 845 const struct wpabuf *token) 846 { 847 u8 *pos; 848 849 if (sae->tmp == NULL) 850 return; 851 852 wpabuf_put_le16(buf, sae->group); /* Finite Cyclic Group */ 853 if (token) { 854 wpabuf_put_buf(buf, token); 855 wpa_hexdump(MSG_DEBUG, "SAE: Anti-clogging token", 856 wpabuf_head(token), wpabuf_len(token)); 857 } 858 pos = wpabuf_put(buf, sae->tmp->prime_len); 859 crypto_bignum_to_bin(sae->tmp->own_commit_scalar, pos, 860 sae->tmp->prime_len, sae->tmp->prime_len); 861 wpa_hexdump(MSG_DEBUG, "SAE: own commit-scalar", 862 pos, sae->tmp->prime_len); 863 if (sae->tmp->ec) { 864 pos = wpabuf_put(buf, 2 * sae->tmp->prime_len); 865 crypto_ec_point_to_bin(sae->tmp->ec, 866 sae->tmp->own_commit_element_ecc, 867 pos, pos + sae->tmp->prime_len); 868 wpa_hexdump(MSG_DEBUG, "SAE: own commit-element(x)", 869 pos, sae->tmp->prime_len); 870 wpa_hexdump(MSG_DEBUG, "SAE: own commit-element(y)", 871 pos + sae->tmp->prime_len, sae->tmp->prime_len); 872 } else { 873 pos = wpabuf_put(buf, sae->tmp->prime_len); 874 crypto_bignum_to_bin(sae->tmp->own_commit_element_ffc, pos, 875 sae->tmp->prime_len, sae->tmp->prime_len); 876 wpa_hexdump(MSG_DEBUG, "SAE: own commit-element", 877 pos, sae->tmp->prime_len); 878 } 879 } 880 881 882 u16 sae_group_allowed(struct sae_data *sae, int *allowed_groups, u16 group) 883 { 884 if (allowed_groups) { 885 int i; 886 for (i = 0; allowed_groups[i] > 0; i++) { 887 if (allowed_groups[i] == group) 888 break; 889 } 890 if (allowed_groups[i] != group) { 891 wpa_printf(MSG_DEBUG, "SAE: Proposed group %u not " 892 "enabled in the current configuration", 893 group); 894 return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED; 895 } 896 } 897 898 if (sae->state == SAE_COMMITTED && group != sae->group) { 899 wpa_printf(MSG_DEBUG, "SAE: Do not allow group to be changed"); 900 return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED; 901 } 902 903 if (group != sae->group && sae_set_group(sae, group) < 0) { 904 wpa_printf(MSG_DEBUG, "SAE: Unsupported Finite Cyclic Group %u", 905 group); 906 return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED; 907 } 908 909 if (sae->tmp == NULL) { 910 wpa_printf(MSG_DEBUG, "SAE: Group information not yet initialized"); 911 return WLAN_STATUS_UNSPECIFIED_FAILURE; 912 } 913 914 if (sae->tmp->dh && !allowed_groups) { 915 wpa_printf(MSG_DEBUG, "SAE: Do not allow FFC group %u without " 916 "explicit configuration enabling it", group); 917 return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED; 918 } 919 920 return WLAN_STATUS_SUCCESS; 921 } 922 923 924 static void sae_parse_commit_token(struct sae_data *sae, const u8 **pos, 925 const u8 *end, const u8 **token, 926 size_t *token_len) 927 { 928 if ((sae->tmp->ec ? 3 : 2) * sae->tmp->prime_len < end - *pos) { 929 size_t tlen = end - (*pos + (sae->tmp->ec ? 3 : 2) * 930 sae->tmp->prime_len); 931 wpa_hexdump(MSG_DEBUG, "SAE: Anti-Clogging Token", *pos, tlen); 932 if (token) 933 *token = *pos; 934 if (token_len) 935 *token_len = tlen; 936 *pos += tlen; 937 } else { 938 if (token) 939 *token = NULL; 940 if (token_len) 941 *token_len = 0; 942 } 943 } 944 945 946 static u16 sae_parse_commit_scalar(struct sae_data *sae, const u8 **pos, 947 const u8 *end) 948 { 949 struct crypto_bignum *peer_scalar; 950 951 if (sae->tmp->prime_len > end - *pos) { 952 wpa_printf(MSG_DEBUG, "SAE: Not enough data for scalar"); 953 return WLAN_STATUS_UNSPECIFIED_FAILURE; 954 } 955 956 peer_scalar = crypto_bignum_init_set(*pos, sae->tmp->prime_len); 957 if (peer_scalar == NULL) 958 return WLAN_STATUS_UNSPECIFIED_FAILURE; 959 960 /* 961 * IEEE Std 802.11-2012, 11.3.8.6.1: If there is a protocol instance for 962 * the peer and it is in Authenticated state, the new Commit Message 963 * shall be dropped if the peer-scalar is identical to the one used in 964 * the existing protocol instance. 965 */ 966 if (sae->state == SAE_ACCEPTED && sae->peer_commit_scalar && 967 crypto_bignum_cmp(sae->peer_commit_scalar, peer_scalar) == 0) { 968 wpa_printf(MSG_DEBUG, "SAE: Do not accept re-use of previous " 969 "peer-commit-scalar"); 970 crypto_bignum_deinit(peer_scalar, 0); 971 return WLAN_STATUS_UNSPECIFIED_FAILURE; 972 } 973 974 /* 1 < scalar < r */ 975 if (crypto_bignum_is_zero(peer_scalar) || 976 crypto_bignum_is_one(peer_scalar) || 977 crypto_bignum_cmp(peer_scalar, sae->tmp->order) >= 0) { 978 wpa_printf(MSG_DEBUG, "SAE: Invalid peer scalar"); 979 crypto_bignum_deinit(peer_scalar, 0); 980 return WLAN_STATUS_UNSPECIFIED_FAILURE; 981 } 982 983 984 crypto_bignum_deinit(sae->peer_commit_scalar, 0); 985 sae->peer_commit_scalar = peer_scalar; 986 wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-scalar", 987 *pos, sae->tmp->prime_len); 988 *pos += sae->tmp->prime_len; 989 990 return WLAN_STATUS_SUCCESS; 991 } 992 993 994 static u16 sae_parse_commit_element_ecc(struct sae_data *sae, const u8 *pos, 995 const u8 *end) 996 { 997 u8 prime[SAE_MAX_ECC_PRIME_LEN]; 998 999 if (2 * sae->tmp->prime_len > end - pos) { 1000 wpa_printf(MSG_DEBUG, "SAE: Not enough data for " 1001 "commit-element"); 1002 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1003 } 1004 1005 if (crypto_bignum_to_bin(sae->tmp->prime, prime, sizeof(prime), 1006 sae->tmp->prime_len) < 0) 1007 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1008 1009 /* element x and y coordinates < p */ 1010 if (os_memcmp(pos, prime, sae->tmp->prime_len) >= 0 || 1011 os_memcmp(pos + sae->tmp->prime_len, prime, 1012 sae->tmp->prime_len) >= 0) { 1013 wpa_printf(MSG_DEBUG, "SAE: Invalid coordinates in peer " 1014 "element"); 1015 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1016 } 1017 1018 wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element(x)", 1019 pos, sae->tmp->prime_len); 1020 wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element(y)", 1021 pos + sae->tmp->prime_len, sae->tmp->prime_len); 1022 1023 crypto_ec_point_deinit(sae->tmp->peer_commit_element_ecc, 0); 1024 sae->tmp->peer_commit_element_ecc = 1025 crypto_ec_point_from_bin(sae->tmp->ec, pos); 1026 if (sae->tmp->peer_commit_element_ecc == NULL) 1027 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1028 1029 if (!crypto_ec_point_is_on_curve(sae->tmp->ec, 1030 sae->tmp->peer_commit_element_ecc)) { 1031 wpa_printf(MSG_DEBUG, "SAE: Peer element is not on curve"); 1032 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1033 } 1034 1035 return WLAN_STATUS_SUCCESS; 1036 } 1037 1038 1039 static u16 sae_parse_commit_element_ffc(struct sae_data *sae, const u8 *pos, 1040 const u8 *end) 1041 { 1042 struct crypto_bignum *res, *one; 1043 const u8 one_bin[1] = { 0x01 }; 1044 1045 if (sae->tmp->prime_len > end - pos) { 1046 wpa_printf(MSG_DEBUG, "SAE: Not enough data for " 1047 "commit-element"); 1048 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1049 } 1050 wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element", pos, 1051 sae->tmp->prime_len); 1052 1053 crypto_bignum_deinit(sae->tmp->peer_commit_element_ffc, 0); 1054 sae->tmp->peer_commit_element_ffc = 1055 crypto_bignum_init_set(pos, sae->tmp->prime_len); 1056 if (sae->tmp->peer_commit_element_ffc == NULL) 1057 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1058 /* 1 < element < p - 1 */ 1059 res = crypto_bignum_init(); 1060 one = crypto_bignum_init_set(one_bin, sizeof(one_bin)); 1061 if (!res || !one || 1062 crypto_bignum_sub(sae->tmp->prime, one, res) || 1063 crypto_bignum_is_zero(sae->tmp->peer_commit_element_ffc) || 1064 crypto_bignum_is_one(sae->tmp->peer_commit_element_ffc) || 1065 crypto_bignum_cmp(sae->tmp->peer_commit_element_ffc, res) >= 0) { 1066 crypto_bignum_deinit(res, 0); 1067 crypto_bignum_deinit(one, 0); 1068 wpa_printf(MSG_DEBUG, "SAE: Invalid peer element"); 1069 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1070 } 1071 crypto_bignum_deinit(one, 0); 1072 1073 /* scalar-op(r, ELEMENT) = 1 modulo p */ 1074 if (crypto_bignum_exptmod(sae->tmp->peer_commit_element_ffc, 1075 sae->tmp->order, sae->tmp->prime, res) < 0 || 1076 !crypto_bignum_is_one(res)) { 1077 wpa_printf(MSG_DEBUG, "SAE: Invalid peer element (scalar-op)"); 1078 crypto_bignum_deinit(res, 0); 1079 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1080 } 1081 crypto_bignum_deinit(res, 0); 1082 1083 return WLAN_STATUS_SUCCESS; 1084 } 1085 1086 1087 static u16 sae_parse_commit_element(struct sae_data *sae, const u8 *pos, 1088 const u8 *end) 1089 { 1090 if (sae->tmp->dh) 1091 return sae_parse_commit_element_ffc(sae, pos, end); 1092 return sae_parse_commit_element_ecc(sae, pos, end); 1093 } 1094 1095 1096 u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len, 1097 const u8 **token, size_t *token_len, int *allowed_groups) 1098 { 1099 const u8 *pos = data, *end = data + len; 1100 u16 res; 1101 1102 /* Check Finite Cyclic Group */ 1103 if (end - pos < 2) 1104 return WLAN_STATUS_UNSPECIFIED_FAILURE; 1105 res = sae_group_allowed(sae, allowed_groups, WPA_GET_LE16(pos)); 1106 if (res != WLAN_STATUS_SUCCESS) 1107 return res; 1108 pos += 2; 1109 1110 /* Optional Anti-Clogging Token */ 1111 sae_parse_commit_token(sae, &pos, end, token, token_len); 1112 1113 /* commit-scalar */ 1114 res = sae_parse_commit_scalar(sae, &pos, end); 1115 if (res != WLAN_STATUS_SUCCESS) 1116 return res; 1117 1118 /* commit-element */ 1119 res = sae_parse_commit_element(sae, pos, end); 1120 if (res != WLAN_STATUS_SUCCESS) 1121 return res; 1122 1123 /* 1124 * Check whether peer-commit-scalar and PEER-COMMIT-ELEMENT are same as 1125 * the values we sent which would be evidence of a reflection attack. 1126 */ 1127 if (!sae->tmp->own_commit_scalar || 1128 crypto_bignum_cmp(sae->tmp->own_commit_scalar, 1129 sae->peer_commit_scalar) != 0 || 1130 (sae->tmp->dh && 1131 (!sae->tmp->own_commit_element_ffc || 1132 crypto_bignum_cmp(sae->tmp->own_commit_element_ffc, 1133 sae->tmp->peer_commit_element_ffc) != 0)) || 1134 (sae->tmp->ec && 1135 (!sae->tmp->own_commit_element_ecc || 1136 crypto_ec_point_cmp(sae->tmp->ec, 1137 sae->tmp->own_commit_element_ecc, 1138 sae->tmp->peer_commit_element_ecc) != 0))) 1139 return WLAN_STATUS_SUCCESS; /* scalars/elements are different */ 1140 1141 /* 1142 * This is a reflection attack - return special value to trigger caller 1143 * to silently discard the frame instead of replying with a specific 1144 * status code. 1145 */ 1146 return SAE_SILENTLY_DISCARD; 1147 } 1148 1149 1150 static void sae_cn_confirm(struct sae_data *sae, const u8 *sc, 1151 const struct crypto_bignum *scalar1, 1152 const u8 *element1, size_t element1_len, 1153 const struct crypto_bignum *scalar2, 1154 const u8 *element2, size_t element2_len, 1155 u8 *confirm) 1156 { 1157 const u8 *addr[5]; 1158 size_t len[5]; 1159 u8 scalar_b1[SAE_MAX_PRIME_LEN], scalar_b2[SAE_MAX_PRIME_LEN]; 1160 1161 /* Confirm 1162 * CN(key, X, Y, Z, ...) = 1163 * HMAC-SHA256(key, D2OS(X) || D2OS(Y) || D2OS(Z) | ...) 1164 * confirm = CN(KCK, send-confirm, commit-scalar, COMMIT-ELEMENT, 1165 * peer-commit-scalar, PEER-COMMIT-ELEMENT) 1166 * verifier = CN(KCK, peer-send-confirm, peer-commit-scalar, 1167 * PEER-COMMIT-ELEMENT, commit-scalar, COMMIT-ELEMENT) 1168 */ 1169 addr[0] = sc; 1170 len[0] = 2; 1171 crypto_bignum_to_bin(scalar1, scalar_b1, sizeof(scalar_b1), 1172 sae->tmp->prime_len); 1173 addr[1] = scalar_b1; 1174 len[1] = sae->tmp->prime_len; 1175 addr[2] = element1; 1176 len[2] = element1_len; 1177 crypto_bignum_to_bin(scalar2, scalar_b2, sizeof(scalar_b2), 1178 sae->tmp->prime_len); 1179 addr[3] = scalar_b2; 1180 len[3] = sae->tmp->prime_len; 1181 addr[4] = element2; 1182 len[4] = element2_len; 1183 hmac_sha256_vector(sae->tmp->kck, sizeof(sae->tmp->kck), 5, addr, len, 1184 confirm); 1185 } 1186 1187 1188 static void sae_cn_confirm_ecc(struct sae_data *sae, const u8 *sc, 1189 const struct crypto_bignum *scalar1, 1190 const struct crypto_ec_point *element1, 1191 const struct crypto_bignum *scalar2, 1192 const struct crypto_ec_point *element2, 1193 u8 *confirm) 1194 { 1195 u8 element_b1[2 * SAE_MAX_ECC_PRIME_LEN]; 1196 u8 element_b2[2 * SAE_MAX_ECC_PRIME_LEN]; 1197 1198 crypto_ec_point_to_bin(sae->tmp->ec, element1, element_b1, 1199 element_b1 + sae->tmp->prime_len); 1200 crypto_ec_point_to_bin(sae->tmp->ec, element2, element_b2, 1201 element_b2 + sae->tmp->prime_len); 1202 1203 sae_cn_confirm(sae, sc, scalar1, element_b1, 2 * sae->tmp->prime_len, 1204 scalar2, element_b2, 2 * sae->tmp->prime_len, confirm); 1205 } 1206 1207 1208 static void sae_cn_confirm_ffc(struct sae_data *sae, const u8 *sc, 1209 const struct crypto_bignum *scalar1, 1210 const struct crypto_bignum *element1, 1211 const struct crypto_bignum *scalar2, 1212 const struct crypto_bignum *element2, 1213 u8 *confirm) 1214 { 1215 u8 element_b1[SAE_MAX_PRIME_LEN]; 1216 u8 element_b2[SAE_MAX_PRIME_LEN]; 1217 1218 crypto_bignum_to_bin(element1, element_b1, sizeof(element_b1), 1219 sae->tmp->prime_len); 1220 crypto_bignum_to_bin(element2, element_b2, sizeof(element_b2), 1221 sae->tmp->prime_len); 1222 1223 sae_cn_confirm(sae, sc, scalar1, element_b1, sae->tmp->prime_len, 1224 scalar2, element_b2, sae->tmp->prime_len, confirm); 1225 } 1226 1227 1228 void sae_write_confirm(struct sae_data *sae, struct wpabuf *buf) 1229 { 1230 const u8 *sc; 1231 1232 if (sae->tmp == NULL) 1233 return; 1234 1235 /* Send-Confirm */ 1236 sc = wpabuf_put(buf, 0); 1237 wpabuf_put_le16(buf, sae->send_confirm); 1238 sae->send_confirm++; 1239 1240 if (sae->tmp->ec) 1241 sae_cn_confirm_ecc(sae, sc, sae->tmp->own_commit_scalar, 1242 sae->tmp->own_commit_element_ecc, 1243 sae->peer_commit_scalar, 1244 sae->tmp->peer_commit_element_ecc, 1245 wpabuf_put(buf, SHA256_MAC_LEN)); 1246 else 1247 sae_cn_confirm_ffc(sae, sc, sae->tmp->own_commit_scalar, 1248 sae->tmp->own_commit_element_ffc, 1249 sae->peer_commit_scalar, 1250 sae->tmp->peer_commit_element_ffc, 1251 wpabuf_put(buf, SHA256_MAC_LEN)); 1252 } 1253 1254 1255 int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len) 1256 { 1257 u8 verifier[SHA256_MAC_LEN]; 1258 1259 if (len < 2 + SHA256_MAC_LEN) { 1260 wpa_printf(MSG_DEBUG, "SAE: Too short confirm message"); 1261 return -1; 1262 } 1263 1264 wpa_printf(MSG_DEBUG, "SAE: peer-send-confirm %u", WPA_GET_LE16(data)); 1265 1266 if (sae->tmp == NULL) { 1267 wpa_printf(MSG_DEBUG, "SAE: Temporary data not yet available"); 1268 return -1; 1269 } 1270 1271 if (sae->tmp->ec) 1272 sae_cn_confirm_ecc(sae, data, sae->peer_commit_scalar, 1273 sae->tmp->peer_commit_element_ecc, 1274 sae->tmp->own_commit_scalar, 1275 sae->tmp->own_commit_element_ecc, 1276 verifier); 1277 else 1278 sae_cn_confirm_ffc(sae, data, sae->peer_commit_scalar, 1279 sae->tmp->peer_commit_element_ffc, 1280 sae->tmp->own_commit_scalar, 1281 sae->tmp->own_commit_element_ffc, 1282 verifier); 1283 1284 if (os_memcmp_const(verifier, data + 2, SHA256_MAC_LEN) != 0) { 1285 wpa_printf(MSG_DEBUG, "SAE: Confirm mismatch"); 1286 wpa_hexdump(MSG_DEBUG, "SAE: Received confirm", 1287 data + 2, SHA256_MAC_LEN); 1288 wpa_hexdump(MSG_DEBUG, "SAE: Calculated verifier", 1289 verifier, SHA256_MAC_LEN); 1290 return -1; 1291 } 1292 1293 return 0; 1294 } 1295
