C_DigestFinal

CK_DECLARE_FUNCTION( CK_RV, C_DigestFinal )( CK_SESSION_HANDLE hSession,
                                             CK_BYTE_PTR pDigest,
                                             CK_ULONG_PTR pulDigestLen )
{
    P11Session_t * pxSession = prvSessionPointerFromHandle( hSession );
    CK_RV xResult = prvCheckValidSessionAndModule( pxSession );
    int32_t lMbedTLSResult = 0;
 
 
    if( pulDigestLen == NULL )
    {
        LogError( ( "Failed to finish digest operation. Digest Length pointer "
                    "was NULL." ) );
        xResult = CKR_ARGUMENTS_BAD;
    }
 
    if( xResult == CKR_OK )
    {
        if( pxSession->xOperationDigestMechanism != CKM_SHA256 )
        {
            LogError( ( "Failed to finish digest operation. Digest operation "
                        "was not initialized." ) );
            xResult = CKR_OPERATION_NOT_INITIALIZED;
            pxSession->xOperationDigestMechanism = pkcs11NO_OPERATION;
        }
    }
 
    if( xResult == CKR_OK )
    {
        if( pDigest == NULL )
        {
            /* Supply the required buffer size. */
            *pulDigestLen = ( CK_ULONG ) pkcs11SHA256_DIGEST_LENGTH;
        }
        else
        {
            if( *pulDigestLen == ( CK_ULONG ) pkcs11SHA256_DIGEST_LENGTH )
            {
                lMbedTLSResult = mbedtls_sha256_finish_ret( &pxSession->xSHA256Context, pDigest );
 
                if( 0 != lMbedTLSResult )
                {
                    LogError( ( "Failed to finish digest operation. "
                                "mbedtls_sha256_finish_ret failed: mbed TLS "
                                "error = %s : %s.",
                                mbedtlsHighLevelCodeOrDefault( lMbedTLSResult ),
                                mbedtlsLowLevelCodeOrDefault( lMbedTLSResult ) ) );
                    xResult = CKR_FUNCTION_FAILED;
                }
 
                pxSession->xOperationDigestMechanism = pkcs11NO_OPERATION;
            }
            else
            {
                LogError( ( "Failed to finish digest operation. Received a "
                            "buffer that was an unexpected size. Expected %lu and "
                            "received %lu.",
                            ( unsigned long int ) pkcs11SHA256_DIGEST_LENGTH,
                            ( unsigned long int ) *pulDigestLen ) );
                xResult = CKR_BUFFER_TOO_SMALL;
            }
        }
    }
 
    if( ( xResult != CKR_OK ) && ( xResult != CKR_BUFFER_TOO_SMALL ) &&
        ( xResult != CKR_SESSION_HANDLE_INVALID ) &&
        ( xResult != CKR_OPERATION_NOT_INITIALIZED ) )
    {
        LogDebug( ( "Error occurred, tearing down digest operation." ) );
        pxSession->xOperationDigestMechanism = pkcs11NO_OPERATION;
        mbedtls_sha256_free( &pxSession->xSHA256Context );
    }
 
    return xResult;
}