library/psa_crypto_storage_its.c

/*
 *  PSA storage backend for persistent keys using psa_its APIs.
 */
/*  Copyright (C) 2018, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#if defined(MBEDTLS_CONFIG_FILE)
#include MBEDTLS_CONFIG_FILE
#else
#include "mbedtls/config.h"
#endif

#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_ITS_C)

#include "psa/crypto.h"
#include "psa_crypto_storage_backend.h"
#include "psa/internal_trusted_storage.h"

#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#endif

static psa_status_t its_to_psa_error( psa_its_status_t ret )
{
    switch( ret )
    {
        case PSA_ITS_SUCCESS:
            return( PSA_SUCCESS );

        case PSA_ITS_ERROR_UID_NOT_FOUND:
            return( PSA_ERROR_EMPTY_SLOT );

        case PSA_ITS_ERROR_STORAGE_FAILURE:
            return( PSA_ERROR_STORAGE_FAILURE );

        case PSA_ITS_ERROR_INSUFFICIENT_SPACE:
            return( PSA_ERROR_INSUFFICIENT_STORAGE );

        case PSA_ITS_ERROR_OFFSET_INVALID:
        case PSA_ITS_ERROR_INCORRECT_SIZE:
        case PSA_ITS_ERROR_INVALID_ARGUMENTS:
            return( PSA_ERROR_INVALID_ARGUMENT );

        case PSA_ITS_ERROR_FLAGS_NOT_SUPPORTED:
            return( PSA_ERROR_NOT_SUPPORTED );

        case PSA_ITS_ERROR_WRITE_ONCE:
            return( PSA_ERROR_OCCUPIED_SLOT );

        default:
            return( PSA_ERROR_UNKNOWN_ERROR );
    }
}

static uint32_t psa_its_identifier_of_slot( psa_key_id_t key )
{
    return( key );
}

psa_status_t psa_crypto_storage_load( const psa_key_id_t key, uint8_t *data,
                                      size_t data_size )
{
    psa_its_status_t ret;
    psa_status_t status;
    uint32_t data_identifier = psa_its_identifier_of_slot( key );
    struct psa_its_info_t data_identifier_info;

    ret = psa_its_get_info( data_identifier, &data_identifier_info );
    status = its_to_psa_error( ret );
    if( status != PSA_SUCCESS )
        return( status );

    ret = psa_its_get( data_identifier, 0, data_size, data );
    status = its_to_psa_error( ret );

    return( status );
}

int psa_is_key_present_in_storage( const psa_key_id_t key )
{
    psa_its_status_t ret;
    uint32_t data_identifier = psa_its_identifier_of_slot( key );
    struct psa_its_info_t data_identifier_info;

    ret = psa_its_get_info( data_identifier, &data_identifier_info );

    if( ret == PSA_ITS_ERROR_UID_NOT_FOUND )
        return( 0 );
    return( 1 );
}

psa_status_t psa_crypto_storage_store( const psa_key_id_t key,
                                       const uint8_t *data,
                                       size_t data_length )
{
    psa_its_status_t ret;
    psa_status_t status;
    uint32_t data_identifier = psa_its_identifier_of_slot( key );
    struct psa_its_info_t data_identifier_info;

    if( psa_is_key_present_in_storage( key ) == 1 )
        return( PSA_ERROR_OCCUPIED_SLOT );

    ret = psa_its_set( data_identifier, data_length, data, 0 );
    status = its_to_psa_error( ret );
    if( status != PSA_SUCCESS )
    {
        return( PSA_ERROR_STORAGE_FAILURE );
    }

    ret = psa_its_get_info( data_identifier, &data_identifier_info );
    status = its_to_psa_error( ret );
    if( status != PSA_SUCCESS )
    {
        goto exit;
    }

    if( data_identifier_info.size != data_length )
    {
        status = PSA_ERROR_STORAGE_FAILURE;
        goto exit;
    }

exit:
    if( status != PSA_SUCCESS )
        psa_its_remove( data_identifier );
    return( status );
}

psa_status_t psa_destroy_persistent_key( const psa_key_id_t key )
{
    psa_its_status_t ret;
    uint32_t data_identifier = psa_its_identifier_of_slot( key );
    struct psa_its_info_t data_identifier_info;

    ret = psa_its_get_info( data_identifier, &data_identifier_info );
    if( ret == PSA_ITS_ERROR_UID_NOT_FOUND )
        return( PSA_SUCCESS );

    if( psa_its_remove( data_identifier ) != PSA_ITS_SUCCESS )
        return( PSA_ERROR_STORAGE_FAILURE );

    ret = psa_its_get_info( data_identifier, &data_identifier_info );
    if( ret != PSA_ITS_ERROR_UID_NOT_FOUND )
        return( PSA_ERROR_STORAGE_FAILURE );

    return( PSA_SUCCESS );
}

psa_status_t psa_crypto_storage_get_data_length( const psa_key_id_t key,
                                                 size_t *data_length )
{
    psa_its_status_t ret;
    psa_status_t status;
    uint32_t data_identifier = psa_its_identifier_of_slot( key );
    struct psa_its_info_t data_identifier_info;

    ret = psa_its_get_info( data_identifier, &data_identifier_info );
    status = its_to_psa_error( ret );
    if( status != PSA_SUCCESS )
        return( status );

    *data_length = (size_t) data_identifier_info.size;

    return( PSA_SUCCESS );
}

#endif /* MBEDTLS_PSA_CRYPTO_STORAGE_ITS_C */