absl::Status ValidateRsaOaepParameters()

in kmsp11/operation/rsaes_oaep.cc [115:144]

• 27 lines of code
• 6 McCabe index (conditional complexity)

absl::Status ValidateRsaOaepParameters(Object* key, void* parameters,
                                       CK_ULONG parameters_size) {
  if (parameters_size != sizeof(CK_RSA_PKCS_OAEP_PARAMS)) {
    return InvalidMechanismParamError(
        "mechanism parameters must be of type CK_RSA_PKCS_OAEP_PARAMS",
        SOURCE_LOCATION);
  }
  CK_RSA_PKCS_OAEP_PARAMS* params =
      static_cast<CK_RSA_PKCS_OAEP_PARAMS*>(parameters);

  ASSIGN_OR_RETURN(const EVP_MD* digest,
                   DigestForMechanism(*key->algorithm().digest_mechanism));
  RETURN_IF_ERROR(EnsureHashMatches(params->hashAlg, digest));
  RETURN_IF_ERROR(EnsureMgf1HashMatches(params->mgf, digest));

  switch (params->source) {
    case 0:  // For compatibility. See b/217419373.
    case CKZ_DATA_SPECIFIED:
      break;
    default:
      return InvalidMechanismParamError(
          "source for OAEP must be 0 or CKZ_DATA_SPECIFIED", SOURCE_LOCATION);
  }
  if (params->pSourceData != nullptr || params->ulSourceDataLen != 0) {
    return InvalidMechanismParamError("OAEP labels are not supported",
                                      SOURCE_LOCATION);
  }

  return absl::OkStatus();
}