Eliminate harmless non-constant time operations on secret data.

There were several places where the code was non-constant time
 for invalid secret inputs.  These are harmless under sane use
 but get in the way of automatic const-time validation.

(Nonce overflow in signing is not addressed, nor is s==0 in
 signing)
This commit is contained in:
Gregory Maxwell
2020-01-11 01:01:05 +00:00
parent 856a01d6ad
commit 34a67c773b
16 changed files with 154 additions and 101 deletions

View File

@@ -75,12 +75,11 @@ static int secp256k1_eckey_pubkey_tweak_add(const secp256k1_ecmult_context *ctx,
}
static int secp256k1_eckey_privkey_tweak_mul(secp256k1_scalar *key, const secp256k1_scalar *tweak) {
if (secp256k1_scalar_is_zero(tweak)) {
return 0;
}
int ret;
ret = !secp256k1_scalar_is_zero(tweak);
secp256k1_scalar_mul(key, key, tweak);
return 1;
return ret;
}
static int secp256k1_eckey_pubkey_tweak_mul(const secp256k1_ecmult_context *ctx, secp256k1_ge *key, const secp256k1_scalar *tweak) {