openssleddsa_isprivate needs to supply a buffer
openssleddsa_isprivate always succeeds as this always succeeds.
if (EVP_PKEY_get_raw_private_key(pkey, NULL, &len) == 1 && len > 0) {
return (true);
}
A buffer is need to be supplied for EVP_PKEY_get_raw_private_key to fail.