The branch master has been updated via de72274d62a9939e833ab2816360228ba2e1a74b (commit) from a97d19f7ce93845997a8f75f522f0331899ed5f4 (commit)
- Log ----------------------------------------------------------------- commit de72274d62a9939e833ab2816360228ba2e1a74b Author: Billy Brumley <bbrum...@gmail.com> Date: Wed Jul 4 15:35:18 2018 +0300 [crypto/ec] disable SCA mitigations for curves with incomplete parameters Reviewed-by: Rich Salz <rs...@openssl.org> Reviewed-by: Matt Caswell <m...@openssl.org> (Merged from https://github.com/openssl/openssl/pull/6648) ----------------------------------------------------------------------- Summary of changes: crypto/ec/ec_mult.c | 46 ++++++++++++++++++++++++---------------------- 1 file changed, 24 insertions(+), 22 deletions(-) diff --git a/crypto/ec/ec_mult.c b/crypto/ec/ec_mult.c index c821cb8..663db57 100644 --- a/crypto/ec/ec_mult.c +++ b/crypto/ec/ec_mult.c @@ -389,30 +389,32 @@ int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, return EC_POINT_set_to_infinity(group, r); } - /*- - * Handle the common cases where the scalar is secret, enforcing a constant - * time scalar multiplication algorithm. - */ - if ((scalar != NULL) && (num == 0)) { - /*- - * In this case we want to compute scalar * GeneratorPoint: this - * codepath is reached most prominently by (ephemeral) key generation - * of EC cryptosystems (i.e. ECDSA keygen and sign setup, ECDH - * keygen/first half), where the scalar is always secret. This is why - * we ignore if BN_FLG_CONSTTIME is actually set and we always call the - * constant time version. - */ - return ec_mul_consttime(group, r, scalar, NULL, ctx); - } - if ((scalar == NULL) && (num == 1)) { + if (!BN_is_zero(group->order) && !BN_is_zero(group->cofactor)) { /*- - * In this case we want to compute scalar * GenericPoint: this codepath - * is reached most prominently by the second half of ECDH, where the - * secret scalar is multiplied by the peer's public point. To protect - * the secret scalar, we ignore if BN_FLG_CONSTTIME is actually set and - * we always call the constant time version. + * Handle the common cases where the scalar is secret, enforcing a constant + * time scalar multiplication algorithm. */ - return ec_mul_consttime(group, r, scalars[0], points[0], ctx); + if ((scalar != NULL) && (num == 0)) { + /*- + * In this case we want to compute scalar * GeneratorPoint: this + * codepath is reached most prominently by (ephemeral) key generation + * of EC cryptosystems (i.e. ECDSA keygen and sign setup, ECDH + * keygen/first half), where the scalar is always secret. This is why + * we ignore if BN_FLG_CONSTTIME is actually set and we always call the + * constant time version. + */ + return ec_mul_consttime(group, r, scalar, NULL, ctx); + } + if ((scalar == NULL) && (num == 1)) { + /*- + * In this case we want to compute scalar * GenericPoint: this codepath + * is reached most prominently by the second half of ECDH, where the + * secret scalar is multiplied by the peer's public point. To protect + * the secret scalar, we ignore if BN_FLG_CONSTTIME is actually set and + * we always call the constant time version. + */ + return ec_mul_consttime(group, r, scalars[0], points[0], ctx); + } } for (i = 0; i < num; i++) { _____ openssl-commits mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-commits