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Check ECC scalar before multiplication

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A k with more bits than in order doesn't work in ECC scalar
multiplication.
Check private key length in wc_ecc_check_key()
Check private key length in ecc_make_pub_ex()
This commit is contained in:
Sean Parkinson
2020-08-17 10:20:56 +10:00
committed by John Safranek
parent 3be7f3ea3a
commit cb5d6a5c12
1 changed files with 31 additions and 1 deletions
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32
wolfcrypt/src/ecc.c
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@@ -3068,6 +3068,13 @@ int wc_ecc_mulmod_ex2(mp_int* k, ecc_point *G, ecc_point *R, mp_int* a,
goto exit;
}
/* k can't have more bits than order */
if (mp_count_bits(k) > mp_count_bits(order)) {
err = ECC_OUT_OF_RANGE_E;
goto exit;
}
#ifdef ECC_TIMING_RESISTANT
if ((err = mp_init(&t)) != MP_OKAY)
goto exit;
@@ -4194,6 +4201,17 @@ static int ecc_make_pub_ex(ecc_key* key, ecc_curve_spec* curveIn,
}
}
#ifndef WOLFSSL_SP_MATH
if ((err == MP_OKAY) && (mp_iszero(&key->k) || (key->k.sign == MP_NEG) ||
(mp_cmp(&key->k, curve->order) != MP_LT)))
#else
if ((err == MP_OKAY) && (mp_iszero(&key->k) ||
(mp_cmp(&key->k, curve->order) != MP_LT)))
#endif
{
err = ECC_PRIV_KEY_E;
}
if (err == MP_OKAY) {
#ifndef ALT_ECC_SIZE
err = mp_init_multi(pub->x, pub->y, pub->z, NULL, NULL, NULL);
@@ -4207,7 +4225,6 @@ static int ecc_make_pub_ex(ecc_key* key, ecc_curve_spec* curveIn,
#endif
}
if (err != MP_OKAY) {
}
else
@@ -7386,6 +7403,14 @@ int wc_ecc_check_key(ecc_key* key)
err = ecc_check_pubkey_order(key, &key->pubkey, curve->Af, curve->prime,
curve->order);
/* SP 800-56Ar3, section 5.6.2.1.2 */
/* private keys must be in the range [1, n-1] */
if ((err == MP_OKAY) && (key->type == ECC_PRIVATEKEY) &&
(mp_iszero(&key->k) || (key->k.sign == MP_NEG) ||
(mp_cmp(&key->k, curve->order) != MP_LT))) {
err = ECC_PRIV_KEY_E;
}
/* SP 800-56Ar3, section 5.6.2.1.4, method (b) for ECC */
/* private * base generator must equal pubkey */
if (err == MP_OKAY && key->type == ECC_PRIVATEKEY)
@@ -9964,6 +9989,11 @@ int wc_ecc_mulmod_ex2(mp_int* k, ecc_point *G, ecc_point *R, mp_int* a,
if (mp_init(&mu) != MP_OKAY)
return MP_INIT_E;
/* k can't have more bits than order */
if (mp_count_bits(k) > mp_count_bits(order)) {
return ECC_OUT_OF_RANGE_E;
}
#ifndef HAVE_THREAD_LS
if (initMutex == 0) { /* extra sanity check if wolfCrypt_Init not called */
wc_InitMutex(&ecc_fp_lock);