96ebf9efcf
Add a magic header to the storage format used with files. The header is used as an initial check that the data is what we expect, rather than garbage data.
219 lines
7.5 KiB
C
219 lines
7.5 KiB
C
/*
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* PSA persistent key storage
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*/
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/* Copyright (C) 2018, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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#if defined(MBEDTLS_CONFIG_FILE)
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#include MBEDTLS_CONFIG_FILE
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#else
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#include "mbedtls/config.h"
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#endif
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#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
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#include <stdlib.h>
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#include <string.h>
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#include "psa/crypto.h"
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#include "psa_crypto_storage.h"
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#include "psa_crypto_storage_backend.h"
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#include "mbedtls/platform_util.h"
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#if defined(MBEDTLS_PLATFORM_C)
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#include "mbedtls/platform.h"
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#else
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#define mbedtls_calloc calloc
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#define mbedtls_free free
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#endif
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/*
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* 32-bit integer manipulation macros (little endian)
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*/
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#ifndef GET_UINT32_LE
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#define GET_UINT32_LE(n,b,i) \
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{ \
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(n) = ( (uint32_t) (b)[(i) ] ) \
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| ( (uint32_t) (b)[(i) + 1] << 8 ) \
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| ( (uint32_t) (b)[(i) + 2] << 16 ) \
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| ( (uint32_t) (b)[(i) + 3] << 24 ); \
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}
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#endif
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#ifndef PUT_UINT32_LE
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#define PUT_UINT32_LE(n,b,i) \
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{ \
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(b)[(i) ] = (unsigned char) ( ( (n) ) & 0xFF ); \
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(b)[(i) + 1] = (unsigned char) ( ( (n) >> 8 ) & 0xFF ); \
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(b)[(i) + 2] = (unsigned char) ( ( (n) >> 16 ) & 0xFF ); \
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(b)[(i) + 3] = (unsigned char) ( ( (n) >> 24 ) & 0xFF ); \
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}
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#endif
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/**
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* Persistent key storage magic header.
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*/
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#define PSA_KEY_STORAGE_MAGIC_HEADER "PSA\0KEY"
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#define PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH ( sizeof( PSA_KEY_STORAGE_MAGIC_HEADER ) )
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typedef struct {
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uint8_t magic[PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH];
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uint8_t version[4];
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uint8_t type[sizeof( psa_key_type_t )];
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uint8_t policy[sizeof( psa_key_policy_t )];
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uint8_t data_len[4];
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uint8_t key_data[];
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} psa_persistent_key_storage_format;
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void psa_format_key_data_for_storage( const uint8_t *data,
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const size_t data_length,
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const psa_key_type_t type,
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const psa_key_policy_t *policy,
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uint8_t *storage_data )
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{
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psa_persistent_key_storage_format *storage_format =
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(psa_persistent_key_storage_format *) storage_data;
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memcpy( storage_format->magic, PSA_KEY_STORAGE_MAGIC_HEADER, PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH );
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PUT_UINT32_LE(0, storage_format->version, 0);
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PUT_UINT32_LE(type, storage_format->type, 0);
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PUT_UINT32_LE(policy->usage, storage_format->policy, 0);
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PUT_UINT32_LE(policy->alg, storage_format->policy, sizeof( uint32_t ));
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PUT_UINT32_LE(data_length, storage_format->data_len, 0);
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memcpy( storage_format->key_data, data, data_length );
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}
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static psa_status_t check_magic_header( const uint8_t *data )
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{
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if( memcmp( data, PSA_KEY_STORAGE_MAGIC_HEADER,
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PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH ) != 0 )
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return( PSA_ERROR_STORAGE_FAILURE );
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return( PSA_SUCCESS );
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}
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psa_status_t psa_parse_key_data_from_storage( const uint8_t *storage_data,
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size_t storage_data_length,
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uint8_t **key_data,
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size_t *key_data_length,
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psa_key_type_t *type,
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psa_key_policy_t *policy )
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{
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psa_status_t status;
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const psa_persistent_key_storage_format *storage_format =
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(const psa_persistent_key_storage_format *)storage_data;
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uint32_t version;
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if( storage_data_length < sizeof(*storage_format) )
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return( PSA_ERROR_STORAGE_FAILURE );
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status = check_magic_header( storage_data );
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if( status != PSA_SUCCESS )
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return( status );
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GET_UINT32_LE(version, storage_format->version, 0);
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if( version != 0 )
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return( PSA_ERROR_STORAGE_FAILURE );
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GET_UINT32_LE(*key_data_length, storage_format->data_len, 0);
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if( *key_data_length > ( storage_data_length - sizeof(*storage_format) ) ||
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*key_data_length > PSA_CRYPTO_MAX_STORAGE_SIZE )
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return( PSA_ERROR_STORAGE_FAILURE );
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*key_data = mbedtls_calloc( 1, *key_data_length );
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if( *key_data == NULL )
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return( PSA_ERROR_INSUFFICIENT_MEMORY );
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GET_UINT32_LE(*type, storage_format->type, 0);
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GET_UINT32_LE(policy->usage, storage_format->policy, 0);
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GET_UINT32_LE(policy->alg, storage_format->policy, sizeof( uint32_t ));
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memcpy( *key_data, storage_format->key_data, *key_data_length );
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return( PSA_SUCCESS );
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}
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psa_status_t psa_save_persistent_key( const psa_key_slot_t key,
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const psa_key_type_t type,
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const psa_key_policy_t *policy,
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const uint8_t *data,
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const size_t data_length )
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{
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size_t storage_data_length;
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uint8_t *storage_data;
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psa_status_t status;
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if( data_length > PSA_CRYPTO_MAX_STORAGE_SIZE )
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return PSA_ERROR_INSUFFICIENT_STORAGE;
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storage_data_length = data_length + sizeof( psa_persistent_key_storage_format );
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storage_data = mbedtls_calloc( 1, storage_data_length );
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if( storage_data == NULL )
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return( PSA_ERROR_INSUFFICIENT_MEMORY );
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psa_format_key_data_for_storage( data, data_length, type, policy,
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storage_data );
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status = psa_crypto_storage_store( key,
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storage_data, storage_data_length );
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mbedtls_free( storage_data );
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return( status );
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}
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void psa_free_persistent_key_data( uint8_t *key_data, size_t key_data_length )
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{
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if( key_data != NULL )
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{
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mbedtls_platform_zeroize( key_data, key_data_length );
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}
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mbedtls_free( key_data );
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}
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psa_status_t psa_load_persistent_key( psa_key_slot_t key,
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psa_key_type_t *type,
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psa_key_policy_t *policy,
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uint8_t **data,
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size_t *data_length )
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{
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psa_status_t status = PSA_SUCCESS;
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uint8_t *loaded_data;
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size_t storage_data_length = 0;
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status = psa_crypto_storage_get_data_length( key, &storage_data_length );
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if( status != PSA_SUCCESS )
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return( status );
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loaded_data = mbedtls_calloc( 1, storage_data_length );
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if( loaded_data == NULL )
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return( PSA_ERROR_INSUFFICIENT_MEMORY );
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status = psa_crypto_storage_load( key, loaded_data, storage_data_length );
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if( status != PSA_SUCCESS )
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goto exit;
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status = psa_parse_key_data_from_storage( loaded_data, storage_data_length,
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data, data_length, type, policy );
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exit:
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mbedtls_free( loaded_data );
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return( status );
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}
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#endif /* MBEDTLS_PSA_CRYPTO_STORAGE_C */
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