f989dbe6d8
Expose the type of an entry in the SE driver table as an opaque type to other library modules. Soon, driver table entries will have state, and callers will need to be able to access this state through functions using this opaque type. Provide functions to look up a driver by its lifetime and to retrieve the method table from an entry.
133 lines
3.7 KiB
C
133 lines
3.7 KiB
C
/*
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* PSA crypto support for secure element drivers
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*/
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/* Copyright (C) 2019, 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.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
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#include <assert.h>
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#include <string.h>
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#include "psa_crypto_se.h"
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/****************************************************************/
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/* Driver lookup */
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/****************************************************************/
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typedef struct psa_se_drv_table_entry_s
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{
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psa_key_lifetime_t lifetime;
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const psa_drv_se_t *methods;
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} psa_se_drv_table_entry_t;
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static psa_se_drv_table_entry_t driver_table[PSA_MAX_SE_DRIVERS];
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const psa_se_drv_table_entry_t *psa_get_se_driver_entry(
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psa_key_lifetime_t lifetime )
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{
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size_t i;
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if( lifetime == 0 )
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return( NULL );
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for( i = 0; i < PSA_MAX_SE_DRIVERS; i++ )
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{
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if( driver_table[i].lifetime == lifetime )
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return( &driver_table[i] );
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}
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return( NULL );
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}
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const psa_drv_se_t *psa_get_se_driver_methods(
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const psa_se_drv_table_entry_t *drv )
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{
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return( drv->methods );
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}
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const psa_drv_se_t *psa_get_se_driver( psa_key_lifetime_t lifetime )
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{
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const psa_se_drv_table_entry_t *drv = psa_get_se_driver_entry( lifetime );
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if( drv == NULL )
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return( NULL );
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else
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return( drv->methods );
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}
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/****************************************************************/
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/* Driver registration */
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/****************************************************************/
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psa_status_t psa_register_se_driver(
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psa_key_lifetime_t lifetime,
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const psa_drv_se_t *methods)
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{
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size_t i;
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if( methods->hal_version != PSA_DRV_SE_HAL_VERSION )
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return( PSA_ERROR_NOT_SUPPORTED );
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/* Driver table entries are 0-initialized. 0 is not a valid driver
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* lifetime because it means a volatile key. */
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#if defined(static_assert)
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static_assert( PSA_KEY_LIFETIME_VOLATILE == 0,
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"Secure element support requires 0 to mean a volatile key" );
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#endif
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if( lifetime == PSA_KEY_LIFETIME_VOLATILE ||
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lifetime == PSA_KEY_LIFETIME_PERSISTENT )
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{
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return( PSA_ERROR_INVALID_ARGUMENT );
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}
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for( i = 0; i < PSA_MAX_SE_DRIVERS; i++ )
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{
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if( driver_table[i].lifetime == 0 )
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break;
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/* Check that lifetime isn't already in use up to the first free
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* entry. Since entries are created in order and never deleted,
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* there can't be a used entry after the first free entry. */
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if( driver_table[i].lifetime == lifetime )
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return( PSA_ERROR_ALREADY_EXISTS );
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}
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if( i == PSA_MAX_SE_DRIVERS )
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return( PSA_ERROR_INSUFFICIENT_MEMORY );
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driver_table[i].lifetime = lifetime;
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driver_table[i].methods = methods;
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return( PSA_SUCCESS );
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}
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void psa_unregister_all_se_drivers( void )
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{
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memset( driver_table, 0, sizeof( driver_table ) );
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}
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/****************************************************************/
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/* The end */
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/****************************************************************/
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#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
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