mirror of
https://github.com/espressif/esp-idf.git
synced 2024-10-05 20:47:46 -04:00
Merge branch 'bugfix/add_security_patches' into 'master'
esp_wifi:Adding security patch for SAE side channel attacks Closes WIFI-4890 See merge request espressif/esp-idf!20426
This commit is contained in:
Jiang Jiang Jian
commit
f03f3b0a6c
@ -6,6 +6,7 @@ set(srcs "port/os_xtensa.c"
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"src/ap/wpa_auth_ie.c"
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"src/ap/sta_info.c"
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"src/common/sae.c"
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"src/common/dragonfly.c"
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"src/common/wpa_common.c"
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"src/utils/bitfield.c"
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"src/crypto/aes-siv.c"
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@ -16,6 +16,11 @@
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#include "sha256.h"
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#include "mbedtls/pk.h"
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static int crypto_rng_wrapper(void *ctx, unsigned char *buf, size_t len)
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{
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return random_get_bytes(buf, len);
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}
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struct crypto_bignum *crypto_bignum_init(void)
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{
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mbedtls_mpi *bn = os_zalloc(sizeof(mbedtls_mpi));
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@ -235,6 +240,16 @@ int crypto_bignum_is_one(const struct crypto_bignum *a)
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return (mbedtls_mpi_cmp_int((const mbedtls_mpi *) a, 1) == 0);
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}
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int crypto_bignum_is_odd(const struct crypto_bignum *a)
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{
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return (mbedtls_mpi_get_bit((const mbedtls_mpi *) a, 0) == 1);
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}
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int crypto_bignum_rand(struct crypto_bignum *r, const struct crypto_bignum *m)
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{
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return ((mbedtls_mpi_random((mbedtls_mpi *) r, 0, (const mbedtls_mpi *) m,
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crypto_rng_wrapper, NULL) != 0) ? -1 : 0);
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}
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int crypto_bignum_legendre(const struct crypto_bignum *a,
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const struct crypto_bignum *p)
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249
components/wpa_supplicant/src/common/dragonfly.c
Normal file
249
components/wpa_supplicant/src/common/dragonfly.c
Normal file
@ -0,0 +1,249 @@
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/*
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* Shared Dragonfly functionality
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* Copyright (c) 2012-2016, Jouni Malinen <j@w1.fi>
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* Copyright (c) 2019, The Linux Foundation
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*/
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#include "utils/includes.h"
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#include "utils/common.h"
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#include "utils/const_time.h"
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#include "crypto/crypto.h"
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#include "dragonfly.h"
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int dragonfly_suitable_group(int group, int ecc_only)
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{
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/* Enforce REVmd rules on which SAE groups are suitable for production
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* purposes: FFC groups whose prime is >= 3072 bits and ECC groups
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* defined over a prime field whose prime is >= 256 bits. Furthermore,
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* ECC groups defined over a characteristic 2 finite field and ECC
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* groups with a co-factor greater than 1 are not suitable. Disable
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* groups that use Brainpool curves as well for now since they leak more
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* timing information due to the prime not being close to a power of
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* two. */
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return group == 19 || group == 20 || group == 21 ||
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(!ecc_only &&
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(group == 15 || group == 16 || group == 17 || group == 18));
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}
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unsigned int dragonfly_min_pwe_loop_iter(int group)
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{
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if (group == 22 || group == 23 || group == 24) {
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/* FFC groups for which pwd-value is likely to be >= p
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* frequently */
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return 40;
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}
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if (group == 1 || group == 2 || group == 5 || group == 14 ||
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group == 15 || group == 16 || group == 17 || group == 18) {
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/* FFC groups that have prime that is close to a power of two */
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return 1;
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}
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/* Default to 40 (this covers most ECC groups) */
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return 40;
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}
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int dragonfly_get_random_qr_qnr(const struct crypto_bignum *prime,
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struct crypto_bignum **qr,
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struct crypto_bignum **qnr)
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{
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*qr = *qnr = NULL;
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while (!(*qr) || !(*qnr)) {
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struct crypto_bignum *tmp;
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int res;
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tmp = crypto_bignum_init();
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if (!tmp || crypto_bignum_rand(tmp, prime) < 0) {
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crypto_bignum_deinit(tmp, 0);
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break;
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}
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res = crypto_bignum_legendre(tmp, prime);
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if (res == 1 && !(*qr))
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*qr = tmp;
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else if (res == -1 && !(*qnr))
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*qnr = tmp;
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else
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crypto_bignum_deinit(tmp, 0);
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}
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if (*qr && *qnr)
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return 0;
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crypto_bignum_deinit(*qr, 0);
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crypto_bignum_deinit(*qnr, 0);
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*qr = *qnr = NULL;
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return -1;
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}
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static struct crypto_bignum *
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dragonfly_get_rand_1_to_p_1(const struct crypto_bignum *prime)
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{
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struct crypto_bignum *tmp, *pm1, *one;
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tmp = crypto_bignum_init();
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pm1 = crypto_bignum_init();
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one = crypto_bignum_init_set((const u8 *) "\x01", 1);
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if (!tmp || !pm1 || !one ||
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crypto_bignum_sub(prime, one, pm1) < 0 ||
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crypto_bignum_rand(tmp, pm1) < 0 ||
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crypto_bignum_add(tmp, one, tmp) < 0) {
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crypto_bignum_deinit(tmp, 0);
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tmp = NULL;
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}
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crypto_bignum_deinit(pm1, 0);
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crypto_bignum_deinit(one, 0);
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return tmp;
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}
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int dragonfly_is_quadratic_residue_blind(struct crypto_ec *ec,
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const u8 *qr, const u8 *qnr,
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const struct crypto_bignum *val)
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{
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struct crypto_bignum *r, *num, *qr_or_qnr = NULL;
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int check, res = -1;
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u8 qr_or_qnr_bin[DRAGONFLY_MAX_ECC_PRIME_LEN];
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const struct crypto_bignum *prime;
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size_t prime_len;
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unsigned int mask;
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prime = crypto_ec_get_prime(ec);
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prime_len = crypto_ec_prime_len(ec);
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/*
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* Use a blinding technique to mask val while determining whether it is
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* a quadratic residue modulo p to avoid leaking timing information
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* while determining the Legendre symbol.
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*
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* v = val
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* r = a random number between 1 and p-1, inclusive
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* num = (v * r * r) modulo p
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*/
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r = dragonfly_get_rand_1_to_p_1(prime);
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if (!r)
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return -1;
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num = crypto_bignum_init();
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if (!num ||
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crypto_bignum_mulmod(val, r, prime, num) < 0 ||
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crypto_bignum_mulmod(num, r, prime, num) < 0)
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goto fail;
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/*
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* Need to minimize differences in handling different cases, so try to
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* avoid branches and timing differences.
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*
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* If r is odd:
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* num = (num * qr) module p
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* LGR(num, p) = 1 ==> quadratic residue
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* else:
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* num = (num * qnr) module p
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* LGR(num, p) = -1 ==> quadratic residue
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*
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* mask is set to !odd(r)
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*/
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mask = const_time_is_zero(crypto_bignum_is_odd(r));
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const_time_select_bin(mask, qnr, qr, prime_len, qr_or_qnr_bin);
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qr_or_qnr = crypto_bignum_init_set(qr_or_qnr_bin, prime_len);
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if (!qr_or_qnr ||
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crypto_bignum_mulmod(num, qr_or_qnr, prime, num) < 0)
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goto fail;
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/* branchless version of check = odd(r) ? 1 : -1, */
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check = const_time_select_int(mask, -1, 1);
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/* Determine the Legendre symbol on the masked value */
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res = crypto_bignum_legendre(num, prime);
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if (res == -2) {
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res = -1;
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goto fail;
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}
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/* branchless version of res = res == check
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* (res is -1, 0, or 1; check is -1 or 1) */
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mask = const_time_eq(res, check);
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res = const_time_select_int(mask, 1, 0);
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fail:
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crypto_bignum_deinit(num, 1);
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crypto_bignum_deinit(r, 1);
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crypto_bignum_deinit(qr_or_qnr, 1);
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return res;
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}
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static int dragonfly_get_rand_2_to_r_1(struct crypto_bignum *val,
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const struct crypto_bignum *order)
|
||||
{
|
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return crypto_bignum_rand(val, order) == 0 &&
|
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!crypto_bignum_is_zero(val) &&
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!crypto_bignum_is_one(val);
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}
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|
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int dragonfly_generate_scalar(const struct crypto_bignum *order,
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struct crypto_bignum *_rand,
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struct crypto_bignum *_mask,
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struct crypto_bignum *scalar)
|
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{
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int count;
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|
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/* Select two random values rand,mask such that 1 < rand,mask < r and
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* rand + mask mod r > 1. */
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for (count = 0; count < 100; count++) {
|
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if (dragonfly_get_rand_2_to_r_1(_rand, order) &&
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dragonfly_get_rand_2_to_r_1(_mask, order) &&
|
||||
crypto_bignum_add(_rand, _mask, scalar) == 0 &&
|
||||
crypto_bignum_mod(scalar, order, scalar) == 0 &&
|
||||
!crypto_bignum_is_zero(scalar) &&
|
||||
!crypto_bignum_is_one(scalar))
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* This should not be reachable in practice if the random number
|
||||
* generation is working. */
|
||||
wpa_printf(MSG_INFO,
|
||||
"dragonfly: Unable to get randomness for own scalar");
|
||||
return -1;
|
||||
}
|
||||
|
||||
|
||||
/* res = sqrt(val) */
|
||||
int dragonfly_sqrt(struct crypto_ec *ec, const struct crypto_bignum *val,
|
||||
struct crypto_bignum *res)
|
||||
{
|
||||
const struct crypto_bignum *prime;
|
||||
struct crypto_bignum *tmp, *one;
|
||||
int ret = 0;
|
||||
u8 prime_bin[DRAGONFLY_MAX_ECC_PRIME_LEN];
|
||||
size_t prime_len;
|
||||
|
||||
/* For prime p such that p = 3 mod 4, sqrt(w) = w^((p+1)/4) mod p */
|
||||
|
||||
prime = crypto_ec_get_prime(ec);
|
||||
prime_len = crypto_ec_prime_len(ec);
|
||||
tmp = crypto_bignum_init();
|
||||
one = crypto_bignum_init_uint(1);
|
||||
|
||||
if (crypto_bignum_to_bin(prime, prime_bin, sizeof(prime_bin),
|
||||
prime_len) < 0 ||
|
||||
(prime_bin[prime_len - 1] & 0x03) != 3 ||
|
||||
!tmp || !one ||
|
||||
/* tmp = (p+1)/4 */
|
||||
crypto_bignum_add(prime, one, tmp) < 0 ||
|
||||
crypto_bignum_rshift(tmp, 2, tmp) < 0 ||
|
||||
/* res = sqrt(val) */
|
||||
crypto_bignum_exptmod(val, tmp, prime, res) < 0)
|
||||
ret = -1;
|
||||
|
||||
crypto_bignum_deinit(tmp, 0);
|
||||
crypto_bignum_deinit(one, 0);
|
||||
return ret;
|
||||
}
|
||||
33
components/wpa_supplicant/src/common/dragonfly.h
Normal file
33
components/wpa_supplicant/src/common/dragonfly.h
Normal file
@ -0,0 +1,33 @@
|
||||
/*
|
||||
* Shared Dragonfly functionality
|
||||
* Copyright (c) 2012-2016, Jouni Malinen <j@w1.fi>
|
||||
* Copyright (c) 2019, The Linux Foundation
|
||||
*
|
||||
* This software may be distributed under the terms of the BSD license.
|
||||
* See README for more details.
|
||||
*/
|
||||
|
||||
#ifndef DRAGONFLY_H
|
||||
#define DRAGONFLY_H
|
||||
|
||||
#define DRAGONFLY_MAX_ECC_PRIME_LEN 66
|
||||
|
||||
struct crypto_bignum;
|
||||
struct crypto_ec;
|
||||
|
||||
int dragonfly_suitable_group(int group, int ecc_only);
|
||||
unsigned int dragonfly_min_pwe_loop_iter(int group);
|
||||
int dragonfly_get_random_qr_qnr(const struct crypto_bignum *prime,
|
||||
struct crypto_bignum **qr,
|
||||
struct crypto_bignum **qnr);
|
||||
int dragonfly_is_quadratic_residue_blind(struct crypto_ec *ec,
|
||||
const u8 *qr, const u8 *qnr,
|
||||
const struct crypto_bignum *val);
|
||||
int dragonfly_generate_scalar(const struct crypto_bignum *order,
|
||||
struct crypto_bignum *_rand,
|
||||
struct crypto_bignum *_mask,
|
||||
struct crypto_bignum *scalar);
|
||||
int dragonfly_sqrt(struct crypto_ec *ec, const struct crypto_bignum *val,
|
||||
struct crypto_bignum *res);
|
||||
|
||||
#endif /* DRAGONFLY_H */
|
||||
@ -17,6 +17,7 @@
|
||||
#include "crypto/dh_groups.h"
|
||||
#include "ieee802_11_defs.h"
|
||||
#include "sae.h"
|
||||
#include "dragonfly.h"
|
||||
#include "esp_wifi_crypto_types.h"
|
||||
|
||||
int sae_set_group(struct sae_data *sae, int group)
|
||||
@ -176,106 +177,14 @@ static void sae_pwd_seed_key(const u8 *addr1, const u8 *addr2, u8 *key)
|
||||
}
|
||||
}
|
||||
|
||||
static struct crypto_bignum *
|
||||
get_rand_1_to_p_1(const u8 *prime, size_t prime_len, size_t prime_bits,
|
||||
int *r_odd)
|
||||
{
|
||||
for (;;) {
|
||||
struct crypto_bignum *r;
|
||||
u8 tmp[SAE_MAX_ECC_PRIME_LEN];
|
||||
|
||||
if (random_get_bytes(tmp, prime_len) < 0)
|
||||
break;
|
||||
if (prime_bits % 8)
|
||||
buf_shift_right(tmp, prime_len, 8 - prime_bits % 8);
|
||||
if (os_memcmp(tmp, prime, prime_len) >= 0)
|
||||
continue;
|
||||
r = crypto_bignum_init_set(tmp, prime_len);
|
||||
if (!r)
|
||||
break;
|
||||
if (crypto_bignum_is_zero(r)) {
|
||||
crypto_bignum_deinit(r, 0);
|
||||
continue;
|
||||
}
|
||||
|
||||
*r_odd = tmp[prime_len - 1] & 0x01;
|
||||
return r;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static int is_quadratic_residue_blind(struct sae_data *sae,
|
||||
const u8 *prime, size_t bits,
|
||||
const struct crypto_bignum *qr,
|
||||
const struct crypto_bignum *qnr,
|
||||
const struct crypto_bignum *y_sqr)
|
||||
{
|
||||
struct crypto_bignum *r, *num;
|
||||
int r_odd, check, res = -1;
|
||||
|
||||
/*
|
||||
* Use the blinding technique to mask y_sqr while determining
|
||||
* whether it is a quadratic residue modulo p to avoid leaking
|
||||
* timing information while determining the Legendre symbol.
|
||||
*
|
||||
* v = y_sqr
|
||||
* r = a random number between 1 and p-1, inclusive
|
||||
* num = (v * r * r) modulo p
|
||||
*/
|
||||
r = get_rand_1_to_p_1(prime, sae->tmp->prime_len, bits, &r_odd);
|
||||
if (!r)
|
||||
return ESP_FAIL;
|
||||
|
||||
num = crypto_bignum_init();
|
||||
if (!num ||
|
||||
crypto_bignum_mulmod(y_sqr, r, sae->tmp->prime, num) < 0 ||
|
||||
crypto_bignum_mulmod(num, r, sae->tmp->prime, num) < 0)
|
||||
goto fail;
|
||||
|
||||
if (r_odd) {
|
||||
/*
|
||||
* num = (num * qr) module p
|
||||
* LGR(num, p) = 1 ==> quadratic residue
|
||||
*/
|
||||
if (crypto_bignum_mulmod(num, qr, sae->tmp->prime, num) < 0)
|
||||
goto fail;
|
||||
check = 1;
|
||||
} else {
|
||||
/*
|
||||
* num = (num * qnr) module p
|
||||
* LGR(num, p) = -1 ==> quadratic residue
|
||||
*/
|
||||
if (crypto_bignum_mulmod(num, qnr, sae->tmp->prime, num) < 0)
|
||||
goto fail;
|
||||
check = -1;
|
||||
}
|
||||
|
||||
res = crypto_bignum_legendre(num, sae->tmp->prime);
|
||||
if (res == -2) {
|
||||
res = -1;
|
||||
goto fail;
|
||||
}
|
||||
res = res == check;
|
||||
fail:
|
||||
crypto_bignum_deinit(num, 1);
|
||||
crypto_bignum_deinit(r, 1);
|
||||
return res;
|
||||
}
|
||||
|
||||
static int sae_test_pwd_seed_ecc(struct sae_data *sae, const u8 *pwd_seed,
|
||||
const u8 *prime,
|
||||
const struct crypto_bignum *qr,
|
||||
const struct crypto_bignum *qnr,
|
||||
struct crypto_bignum **ret_x_cand)
|
||||
const u8 *prime, const u8 *qr, const u8 *qnr,
|
||||
u8 *pwd_value)
|
||||
{
|
||||
u8 pwd_value[SAE_MAX_ECC_PRIME_LEN];
|
||||
struct crypto_bignum *y_sqr, *x_cand;
|
||||
int res;
|
||||
size_t bits;
|
||||
|
||||
*ret_x_cand = NULL;
|
||||
|
||||
wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN);
|
||||
|
||||
/* pwd-value = KDF-z(pwd-seed, "SAE Hunting and Pecking", p) */
|
||||
@ -284,7 +193,7 @@ static int sae_test_pwd_seed_ecc(struct sae_data *sae, const u8 *pwd_seed,
|
||||
prime, sae->tmp->prime_len, pwd_value, bits) < 0)
|
||||
return ESP_FAIL;
|
||||
if (bits % 8)
|
||||
buf_shift_right(pwd_value, sizeof(pwd_value), 8 - bits % 8);
|
||||
buf_shift_right(pwd_value, sae->tmp->prime_len, 8 - bits % 8);
|
||||
wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value",
|
||||
pwd_value, sae->tmp->prime_len);
|
||||
|
||||
@ -295,30 +204,28 @@ static int sae_test_pwd_seed_ecc(struct sae_data *sae, const u8 *pwd_seed,
|
||||
if (!x_cand)
|
||||
return ESP_FAIL;
|
||||
y_sqr = crypto_ec_point_compute_y_sqr(sae->tmp->ec, x_cand);
|
||||
if (!y_sqr) {
|
||||
crypto_bignum_deinit(x_cand, 1);
|
||||
crypto_bignum_deinit(x_cand, 1);
|
||||
if (!y_sqr)
|
||||
return ESP_FAIL;
|
||||
}
|
||||
|
||||
res = is_quadratic_residue_blind(sae, prime, bits, qr, qnr, y_sqr);
|
||||
res = dragonfly_is_quadratic_residue_blind(sae->tmp->ec, qr, qnr,
|
||||
y_sqr);
|
||||
crypto_bignum_deinit(y_sqr, 1);
|
||||
if (res <= 0) {
|
||||
crypto_bignum_deinit(x_cand, 1);
|
||||
return res;
|
||||
}
|
||||
|
||||
*ret_x_cand = x_cand;
|
||||
return 1;
|
||||
return res;
|
||||
}
|
||||
|
||||
/* Returns -1 on fatal failure, 0 if PWE cannot be derived from the provided
|
||||
* pwd-seed, or 1 if a valid PWE was derived from pwd-seed. */
|
||||
static int sae_test_pwd_seed_ffc(struct sae_data *sae, const u8 *pwd_seed,
|
||||
struct crypto_bignum *pwe)
|
||||
{
|
||||
u8 pwd_value[SAE_MAX_PRIME_LEN];
|
||||
size_t bits = sae->tmp->prime_len * 8;
|
||||
u8 exp[1];
|
||||
struct crypto_bignum *a, *b;
|
||||
int res;
|
||||
struct crypto_bignum *a, *b = NULL;
|
||||
int res, is_val;
|
||||
u8 pwd_value_valid;
|
||||
|
||||
wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN);
|
||||
|
||||
@ -330,16 +237,30 @@ static int sae_test_pwd_seed_ffc(struct sae_data *sae, const u8 *pwd_seed,
|
||||
wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value", pwd_value,
|
||||
sae->tmp->prime_len);
|
||||
|
||||
if (os_memcmp(pwd_value, sae->tmp->dh->prime, sae->tmp->prime_len) >= 0)
|
||||
{
|
||||
wpa_printf(MSG_DEBUG, "SAE: pwd-value >= p");
|
||||
return ESP_OK;
|
||||
}
|
||||
/* Check whether pwd-value < p */
|
||||
res = const_time_memcmp(pwd_value, sae->tmp->dh->prime,
|
||||
sae->tmp->prime_len);
|
||||
/* pwd-value >= p is invalid, so res is < 0 for the valid cases and
|
||||
* the negative sign can be used to fill the mask for constant time
|
||||
* selection */
|
||||
pwd_value_valid = const_time_fill_msb(res);
|
||||
|
||||
/* If pwd-value >= p, force pwd-value to be < p and perform the
|
||||
* calculations anyway to hide timing difference. The derived PWE will
|
||||
* be ignored in that case. */
|
||||
pwd_value[0] = const_time_select_u8(pwd_value_valid, pwd_value[0], 0);
|
||||
|
||||
/* PWE = pwd-value^((p-1)/r) modulo p */
|
||||
|
||||
res = -1;
|
||||
a = crypto_bignum_init_set(pwd_value, sae->tmp->prime_len);
|
||||
|
||||
if (!a)
|
||||
goto fail;
|
||||
|
||||
/* This is an optimization based on the used group that does not depend
|
||||
* on the password in any way, so it is fine to use separate branches
|
||||
* for this step without constant time operations. */
|
||||
if (sae->tmp->dh->safe_prime) {
|
||||
/*
|
||||
* r = (p-1)/2 for the group used here, so this becomes:
|
||||
@ -353,68 +274,34 @@ static int sae_test_pwd_seed_ffc(struct sae_data *sae, const u8 *pwd_seed,
|
||||
b = crypto_bignum_init_set(exp, sizeof(exp));
|
||||
if (b == NULL ||
|
||||
crypto_bignum_sub(sae->tmp->prime, b, b) < 0 ||
|
||||
crypto_bignum_div(b, sae->tmp->order, b) < 0) {
|
||||
crypto_bignum_deinit(b, 0);
|
||||
b = NULL;
|
||||
}
|
||||
crypto_bignum_div(b, sae->tmp->order, b) < 0)
|
||||
goto fail;
|
||||
}
|
||||
|
||||
if (a == NULL || b == NULL)
|
||||
res = -1;
|
||||
else
|
||||
res = crypto_bignum_exptmod(a, b, sae->tmp->prime, pwe);
|
||||
|
||||
crypto_bignum_deinit(a, 0);
|
||||
crypto_bignum_deinit(b, 0);
|
||||
if (!b)
|
||||
goto fail;
|
||||
|
||||
if (res < 0) {
|
||||
wpa_printf(MSG_DEBUG, "SAE: Failed to calculate PWE");
|
||||
return ESP_FAIL;
|
||||
}
|
||||
res = crypto_bignum_exptmod(a, b, sae->tmp->prime, pwe);
|
||||
if (res < 0)
|
||||
goto fail;
|
||||
|
||||
/* if (PWE > 1) --> found */
|
||||
if (crypto_bignum_is_zero(pwe) || crypto_bignum_is_one(pwe)) {
|
||||
wpa_printf(MSG_DEBUG, "SAE: PWE <= 1");
|
||||
return ESP_OK;
|
||||
}
|
||||
|
||||
wpa_printf(MSG_DEBUG, "SAE: PWE found");
|
||||
return 1;
|
||||
}
|
||||
|
||||
static int get_random_qr_qnr(const u8 *prime, size_t prime_len,
|
||||
const struct crypto_bignum *prime_bn,
|
||||
size_t prime_bits, struct crypto_bignum **qr,
|
||||
struct crypto_bignum **qnr)
|
||||
{
|
||||
*qr = NULL;
|
||||
*qnr = NULL;
|
||||
|
||||
while (!(*qr) || !(*qnr)) {
|
||||
u8 tmp[SAE_MAX_ECC_PRIME_LEN];
|
||||
struct crypto_bignum *q;
|
||||
int res;
|
||||
|
||||
if (random_get_bytes(tmp, prime_len) < 0)
|
||||
break;
|
||||
if (prime_bits % 8)
|
||||
buf_shift_right(tmp, prime_len, 8 - prime_bits % 8);
|
||||
if (os_memcmp(tmp, prime, prime_len) >= 0)
|
||||
continue;
|
||||
q = crypto_bignum_init_set(tmp, prime_len);
|
||||
if (!q)
|
||||
break;
|
||||
res = crypto_bignum_legendre(q, prime_bn);
|
||||
|
||||
if (res == 1 && !(*qr))
|
||||
*qr = q;
|
||||
else if (res == -1 && !(*qnr))
|
||||
*qnr = q;
|
||||
else
|
||||
crypto_bignum_deinit(q, 0);
|
||||
}
|
||||
|
||||
return (*qr && *qnr) ? 0 : -1;
|
||||
/* There were no fatal errors in calculations, so determine the return
|
||||
* value using constant time operations. We get here for number of
|
||||
* invalid cases which are cleared here after having performed all the
|
||||
* computation. PWE is valid if pwd-value was less than prime and
|
||||
* PWE > 1. Start with pwd-value check first and then use constant time
|
||||
* operations to clear res to 0 if PWE is 0 or 1.
|
||||
*/
|
||||
res = const_time_select_u8(pwd_value_valid, 1, 0);
|
||||
is_val = crypto_bignum_is_zero(pwe);
|
||||
res = const_time_select_u8(const_time_is_zero(is_val), res, 0);
|
||||
is_val = crypto_bignum_is_one(pwe);
|
||||
res = const_time_select_u8(const_time_is_zero(is_val), res, 0);
|
||||
fail:
|
||||
crypto_bignum_deinit(a, 1);
|
||||
crypto_bignum_deinit(b, 1);
|
||||
return res;
|
||||
}
|
||||
|
||||
static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1,
|
||||
@ -425,34 +312,42 @@ static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1,
|
||||
u8 addrs[2 * ETH_ALEN];
|
||||
const u8 *addr[3];
|
||||
size_t len[3];
|
||||
u8 dummy_password[32];
|
||||
size_t dummy_password_len;
|
||||
u8 *dummy_password, *tmp_password;
|
||||
int pwd_seed_odd = 0;
|
||||
u8 prime[SAE_MAX_ECC_PRIME_LEN];
|
||||
size_t prime_len;
|
||||
struct crypto_bignum *x = NULL, *qr, *qnr;
|
||||
size_t bits;
|
||||
int res;
|
||||
struct crypto_bignum *x = NULL, *y = NULL, *qr = NULL, *qnr = NULL;
|
||||
u8 x_bin[SAE_MAX_ECC_PRIME_LEN];
|
||||
u8 x_cand_bin[SAE_MAX_ECC_PRIME_LEN];
|
||||
u8 qr_bin[SAE_MAX_ECC_PRIME_LEN];
|
||||
u8 qnr_bin[SAE_MAX_ECC_PRIME_LEN];
|
||||
u8 x_y[2 * SAE_MAX_ECC_PRIME_LEN];
|
||||
int res = -1;
|
||||
u8 found = 0; /* 0 (false) or 0xff (true) to be used as const_time_*
|
||||
* mask */
|
||||
unsigned int is_eq;
|
||||
|
||||
dummy_password_len = password_len;
|
||||
if (dummy_password_len > sizeof(dummy_password))
|
||||
dummy_password_len = sizeof(dummy_password);
|
||||
if (random_get_bytes(dummy_password, dummy_password_len) < 0)
|
||||
return ESP_FAIL;
|
||||
os_memset(x_bin, 0, sizeof(x_bin));
|
||||
|
||||
dummy_password = os_malloc(password_len);
|
||||
tmp_password = os_malloc(password_len);
|
||||
if (!dummy_password || !tmp_password ||
|
||||
random_get_bytes(dummy_password, password_len) < 0)
|
||||
goto fail;
|
||||
|
||||
prime_len = sae->tmp->prime_len;
|
||||
if (crypto_bignum_to_bin(sae->tmp->prime, prime, sizeof(prime),
|
||||
prime_len) < 0)
|
||||
return ESP_FAIL;
|
||||
bits = crypto_ec_prime_len_bits(sae->tmp->ec);
|
||||
goto fail;
|
||||
|
||||
/*
|
||||
* Create a random quadratic residue (qr) and quadratic non-residue
|
||||
* (qnr) modulo p for blinding purposes during the loop.
|
||||
*/
|
||||
if (get_random_qr_qnr(prime, prime_len, sae->tmp->prime, bits,
|
||||
&qr, &qnr) < 0)
|
||||
return ESP_FAIL;
|
||||
if (dragonfly_get_random_qr_qnr(sae->tmp->prime, &qr, &qnr) < 0 ||
|
||||
crypto_bignum_to_bin(qr, qr_bin, sizeof(qr_bin), prime_len) < 0 ||
|
||||
crypto_bignum_to_bin(qnr, qnr_bin, sizeof(qnr_bin), prime_len) < 0)
|
||||
goto fail;
|
||||
|
||||
wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
|
||||
password, password_len);
|
||||
@ -465,7 +360,7 @@ static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1,
|
||||
*/
|
||||
sae_pwd_seed_key(addr1, addr2, addrs);
|
||||
|
||||
addr[0] = password;
|
||||
addr[0] = tmp_password;
|
||||
len[0] = password_len;
|
||||
addr[1] = &counter;
|
||||
len[1] = sizeof(counter);
|
||||
@ -475,9 +370,8 @@ static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1,
|
||||
* attacks that attempt to determine the number of iterations required
|
||||
* in the loop.
|
||||
*/
|
||||
for (counter = 1; counter <= k || !x; counter++) {
|
||||
for (counter = 1; counter <= k || !found; counter++) {
|
||||
u8 pwd_seed[SHA256_MAC_LEN];
|
||||
struct crypto_bignum *x_cand;
|
||||
|
||||
if (counter > 200) {
|
||||
/* This should not happen in practice */
|
||||
@ -485,79 +379,119 @@ static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1,
|
||||
break;
|
||||
}
|
||||
|
||||
wpa_printf(MSG_DEBUG, "SAE: counter = %u", counter);
|
||||
wpa_printf(MSG_DEBUG, "SAE: counter = %03u", counter);
|
||||
const_time_select_bin(found, dummy_password, password,
|
||||
password_len, tmp_password);
|
||||
if (hmac_sha256_vector(addrs, sizeof(addrs), 2,
|
||||
addr, len, pwd_seed) < 0)
|
||||
break;
|
||||
|
||||
res = sae_test_pwd_seed_ecc(sae, pwd_seed,
|
||||
prime, qr, qnr, &x_cand);
|
||||
prime, qr_bin, qnr_bin, x_cand_bin);
|
||||
const_time_select_bin(found, x_bin, x_cand_bin, prime_len,
|
||||
x_bin);
|
||||
pwd_seed_odd = const_time_select_u8(
|
||||
found, pwd_seed_odd,
|
||||
pwd_seed[SHA256_MAC_LEN - 1] & 0x01);
|
||||
os_memset(pwd_seed, 0, sizeof(pwd_seed));
|
||||
if (res < 0)
|
||||
goto fail;
|
||||
if (res > 0 && !x) {
|
||||
wpa_printf(MSG_DEBUG,
|
||||
"SAE: Selected pwd-seed with counter %u",
|
||||
counter);
|
||||
x = x_cand;
|
||||
pwd_seed_odd = pwd_seed[SHA256_MAC_LEN - 1] & 0x01;
|
||||
os_memset(pwd_seed, 0, sizeof(pwd_seed));
|
||||
/* Need to minimize differences in handling res == 0 and 1 here
|
||||
* to avoid differences in timing and instruction cache access,
|
||||
* so use const_time_select_*() to make local copies of the
|
||||
* values based on whether this loop iteration was the one that
|
||||
* found the pwd-seed/x. */
|
||||
|
||||
/*
|
||||
* Use a dummy password for the following rounds, if
|
||||
* any.
|
||||
*/
|
||||
addr[0] = dummy_password;
|
||||
len[0] = dummy_password_len;
|
||||
} else if (res > 0) {
|
||||
crypto_bignum_deinit(x_cand, 1);
|
||||
}
|
||||
/* found is 0 or 0xff here and res is 0 or 1. Bitwise OR of them
|
||||
* (with res converted to 0/0xff) handles this in constant time.
|
||||
*/
|
||||
found |= res * 0xff;
|
||||
wpa_printf(MSG_DEBUG, "SAE: pwd-seed result %d found=0x%02x",
|
||||
res, found);
|
||||
}
|
||||
|
||||
if (!x) {
|
||||
if (!found) {
|
||||
wpa_printf(MSG_DEBUG, "SAE: Could not generate PWE");
|
||||
res = -1;
|
||||
goto fail;
|
||||
}
|
||||
|
||||
if (!sae->tmp->pwe_ecc)
|
||||
sae->tmp->pwe_ecc = crypto_ec_point_init(sae->tmp->ec);
|
||||
if (!sae->tmp->pwe_ecc)
|
||||
x = crypto_bignum_init_set(x_bin, prime_len);
|
||||
if (!x) {
|
||||
res = -1;
|
||||
else
|
||||
res = crypto_ec_point_solve_y_coord(sae->tmp->ec,
|
||||
sae->tmp->pwe_ecc, x,
|
||||
pwd_seed_odd);
|
||||
crypto_bignum_deinit(x, 1);
|
||||
if (res < 0) {
|
||||
/*
|
||||
* This should not happen since we already checked that there
|
||||
* is a result.
|
||||
*/
|
||||
goto fail;
|
||||
}
|
||||
/* y = sqrt(x^3 + ax + b) mod p
|
||||
* if LSB(save) == LSB(y): PWE = (x, y)
|
||||
* else: PWE = (x, p - y)
|
||||
*
|
||||
* Calculate y and the two possible values for PWE and after that,
|
||||
* use constant time selection to copy the correct alternative.
|
||||
*/
|
||||
y = crypto_ec_point_compute_y_sqr(sae->tmp->ec, x);
|
||||
if (!y ||
|
||||
dragonfly_sqrt(sae->tmp->ec, y, y) < 0 ||
|
||||
crypto_bignum_to_bin(y, x_y, SAE_MAX_ECC_PRIME_LEN,
|
||||
prime_len) < 0 ||
|
||||
crypto_bignum_sub(sae->tmp->prime, y, y) < 0 ||
|
||||
crypto_bignum_to_bin(y, x_y + SAE_MAX_ECC_PRIME_LEN,
|
||||
SAE_MAX_ECC_PRIME_LEN, prime_len) < 0) {
|
||||
wpa_printf(MSG_DEBUG, "SAE: Could not solve y");
|
||||
goto fail;
|
||||
}
|
||||
|
||||
is_eq = const_time_eq(pwd_seed_odd, x_y[prime_len - 1] & 0x01);
|
||||
const_time_select_bin(is_eq, x_y, x_y + SAE_MAX_ECC_PRIME_LEN,
|
||||
prime_len, x_y + prime_len);
|
||||
os_memcpy(x_y, x_bin, prime_len);
|
||||
wpa_hexdump_key(MSG_DEBUG, "SAE: PWE", x_y, 2 * prime_len);
|
||||
crypto_ec_point_deinit(sae->tmp->pwe_ecc, 1);
|
||||
sae->tmp->pwe_ecc = crypto_ec_point_from_bin(sae->tmp->ec, x_y);
|
||||
if (!sae->tmp->pwe_ecc) {
|
||||
wpa_printf(MSG_DEBUG, "SAE: Could not generate PWE");
|
||||
res = -1;
|
||||
}
|
||||
|
||||
fail:
|
||||
forced_memzero(x_y, sizeof(x_y));
|
||||
crypto_bignum_deinit(qr, 0);
|
||||
crypto_bignum_deinit(qnr, 0);
|
||||
|
||||
crypto_bignum_deinit(y, 1);
|
||||
os_free(dummy_password);
|
||||
bin_clear_free(tmp_password, password_len);
|
||||
crypto_bignum_deinit(x, 1);
|
||||
os_memset(x_bin, 0, sizeof(x_bin));
|
||||
os_memset(x_cand_bin, 0, sizeof(x_cand_bin));
|
||||
return res;
|
||||
}
|
||||
|
||||
static int sae_modp_group_require_masking(int group)
|
||||
{
|
||||
/* Groups for which pwd-value is likely to be >= p frequently */
|
||||
return group == 22 || group == 23 || group == 24;
|
||||
}
|
||||
|
||||
static int sae_derive_pwe_ffc(struct sae_data *sae, const u8 *addr1,
|
||||
const u8 *addr2, const u8 *password,
|
||||
size_t password_len)
|
||||
{
|
||||
u8 counter;
|
||||
u8 counter, k, sel_counter = 0;
|
||||
u8 addrs[2 * ETH_ALEN];
|
||||
const u8 *addr[3];
|
||||
size_t len[3];
|
||||
int found = 0;
|
||||
u8 found = 0; /* 0 (false) or 0xff (true) to be used as const_time_*
|
||||
* mask */
|
||||
u8 mask;
|
||||
struct crypto_bignum *pwe;
|
||||
size_t prime_len = sae->tmp->prime_len * 8;
|
||||
u8 *pwe_buf;
|
||||
crypto_bignum_deinit(sae->tmp->pwe_ffc, 1);
|
||||
sae->tmp->pwe_ffc = NULL;
|
||||
|
||||
if (sae->tmp->pwe_ffc == NULL) {
|
||||
sae->tmp->pwe_ffc = crypto_bignum_init();
|
||||
if (sae->tmp->pwe_ffc == NULL)
|
||||
return ESP_FAIL;
|
||||
}
|
||||
/* Allocate a buffer to maintain selected and candidate PWE for constant
|
||||
* time selection. */
|
||||
pwe_buf = os_zalloc(prime_len * 2);
|
||||
pwe = crypto_bignum_init();
|
||||
if (!pwe_buf || !pwe)
|
||||
goto fail;
|
||||
|
||||
wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
|
||||
password, password_len);
|
||||
@ -574,8 +508,10 @@ static int sae_derive_pwe_ffc(struct sae_data *sae, const u8 *addr1,
|
||||
addr[1] = &counter;
|
||||
len[1] = sizeof(counter);
|
||||
|
||||
for (counter = 1; !found; counter++) {
|
||||
u8 pwd_seed[SHA256_MAC_LEN];
|
||||
k = sae_modp_group_require_masking(sae->group) ? 40 : 1;
|
||||
|
||||
for (counter = 1; counter <= k || !found; counter++) {
|
||||
u8 pwd_seed[SHA256_MAC_LEN];
|
||||
int res;
|
||||
|
||||
if (counter > 200) {
|
||||
@ -584,20 +520,35 @@ static int sae_derive_pwe_ffc(struct sae_data *sae, const u8 *addr1,
|
||||
break;
|
||||
}
|
||||
|
||||
wpa_printf(MSG_DEBUG, "SAE: counter = %u", counter);
|
||||
wpa_printf(MSG_DEBUG, "SAE: counter = %02u", counter);
|
||||
if (hmac_sha256_vector(addrs, sizeof(addrs), 2,
|
||||
addr, len, pwd_seed) < 0)
|
||||
break;
|
||||
res = sae_test_pwd_seed_ffc(sae, pwd_seed, sae->tmp->pwe_ffc);
|
||||
res = sae_test_pwd_seed_ffc(sae, pwd_seed, pwe);
|
||||
/* res is -1 for fatal failure, 0 if a valid PWE was not found,
|
||||
* or 1 if a valid PWE was found. */
|
||||
if (res < 0)
|
||||
break;
|
||||
if (res > 0) {
|
||||
wpa_printf(MSG_DEBUG, "SAE: Use this PWE");
|
||||
found = 1;
|
||||
}
|
||||
/* Store the candidate PWE into the second half of pwe_buf and
|
||||
* the selected PWE in the beginning of pwe_buf using constant
|
||||
* time selection. */
|
||||
if (crypto_bignum_to_bin(pwe, pwe_buf + prime_len, prime_len,
|
||||
prime_len) < 0)
|
||||
break;
|
||||
const_time_select_bin(found, pwe_buf, pwe_buf + prime_len,
|
||||
prime_len, pwe_buf);
|
||||
sel_counter = const_time_select_u8(found, sel_counter, counter);
|
||||
mask = const_time_eq_u8(res, 1);
|
||||
found = const_time_select_u8(found, found, mask);
|
||||
}
|
||||
|
||||
return found ? 0 : -1;
|
||||
if (!found)
|
||||
goto fail;
|
||||
wpa_printf(MSG_DEBUG, "SAE: Use PWE from counter = %02u", sel_counter);
|
||||
sae->tmp->pwe_ffc = crypto_bignum_init_set(pwe_buf, prime_len);
|
||||
fail:
|
||||
crypto_bignum_deinit(pwe, 1);
|
||||
bin_clear_free(pwe_buf, prime_len * 2);
|
||||
return sae->tmp->pwe_ffc ? 0 : -1;
|
||||
}
|
||||
|
||||
static int hkdf_extract(size_t hash_len, const u8 *salt, size_t salt_len,
|
||||
@ -2308,6 +2259,9 @@ int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len)
|
||||
}
|
||||
|
||||
if (sae->tmp->ec) {
|
||||
if (!sae->tmp->peer_commit_element_ecc ||
|
||||
!sae->tmp->own_commit_element_ecc)
|
||||
return ESP_FAIL;
|
||||
if (sae_cn_confirm_ecc(sae, data, sae->peer_commit_scalar,
|
||||
sae->tmp->peer_commit_element_ecc,
|
||||
sae->tmp->own_commit_scalar,
|
||||
@ -2317,6 +2271,9 @@ int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len)
|
||||
return ESP_FAIL;
|
||||
}
|
||||
} else {
|
||||
if (!sae->tmp->peer_commit_element_ffc ||
|
||||
!sae->tmp->own_commit_element_ffc)
|
||||
return ESP_FAIL;
|
||||
if (sae_cn_confirm_ffc(sae, data, sae->peer_commit_scalar,
|
||||
sae->tmp->peer_commit_element_ffc,
|
||||
sae->tmp->own_commit_scalar,
|
||||
|
||||
@ -664,6 +664,18 @@ int crypto_bignum_mulmod(const struct crypto_bignum *a,
|
||||
int crypto_bignum_sqrmod(const struct crypto_bignum *a,
|
||||
const struct crypto_bignum *b,
|
||||
struct crypto_bignum *c);
|
||||
|
||||
/**
|
||||
* crypto_bignum_sqrtmod - returns sqrt(a) (mod b)
|
||||
* @a: Bignum
|
||||
* @b: Bignum
|
||||
* @c: Bignum; used to store the result
|
||||
* Returns: 0 on success, -1 on failure
|
||||
*/
|
||||
int crypto_bignum_sqrtmod(const struct crypto_bignum *a,
|
||||
const struct crypto_bignum *b,
|
||||
struct crypto_bignum *c);
|
||||
|
||||
/**
|
||||
* crypto_bignum_rshift - r = a >> n
|
||||
* @a: Bignum
|
||||
@ -704,6 +716,13 @@ int crypto_bignum_is_zero(const struct crypto_bignum *a);
|
||||
*/
|
||||
int crypto_bignum_is_one(const struct crypto_bignum *a);
|
||||
|
||||
/**
|
||||
* crypto_bignum_is_odd - Is the given bignum odd
|
||||
* @a: Bignum
|
||||
* Returns: 1 if @a is odd or 0 if not
|
||||
*/
|
||||
int crypto_bignum_is_odd(const struct crypto_bignum *a);
|
||||
|
||||
/**
|
||||
* crypto_bignum_legendre - Compute the Legendre symbol (a/p)
|
||||
* @a: Bignum
|
||||
|
||||
Loading…
Reference in New Issue
Block a user