mbedtls/library/psa_crypto_slot_management.c

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/*
* PSA crypto layer on top of Mbed TLS crypto
*/
/* 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.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_PSA_CRYPTO_C)
#include "psa_crypto_service_integration.h"
#include "psa/crypto.h"
#include "psa_crypto_core.h"
#include "psa_crypto_slot_management.h"
#include "psa_crypto_storage.h"
#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
#include "psa_crypto_se.h"
#endif
#include <stdlib.h>
#include <string.h>
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#define mbedtls_calloc calloc
#define mbedtls_free free
#endif
#define ARRAY_LENGTH( array ) ( sizeof( array ) / sizeof( *( array ) ) )
typedef struct
{
psa_key_slot_t key_slots[PSA_KEY_SLOT_COUNT];
unsigned key_slots_initialized : 1;
} psa_global_data_t;
static psa_global_data_t global_data;
/* Access a key slot at the given handle. The handle of a key slot is
* the index of the slot in the global slot array, plus one so that handles
* start at 1 and not 0. */
psa_status_t psa_get_key_slot( psa_key_handle_t handle,
psa_key_slot_t **p_slot )
{
psa_key_slot_t *slot = NULL;
if( ! global_data.key_slots_initialized )
return( PSA_ERROR_BAD_STATE );
/* 0 is not a valid handle under any circumstance. This
* implementation provides slots number 1 to N where N is the
* number of available slots. */
if( handle == 0 || handle > ARRAY_LENGTH( global_data.key_slots ) )
return( PSA_ERROR_INVALID_HANDLE );
slot = &global_data.key_slots[handle - 1];
/* If the slot isn't occupied, the handle is invalid. */
if( ! psa_is_key_slot_occupied( slot ) )
return( PSA_ERROR_INVALID_HANDLE );
*p_slot = slot;
return( PSA_SUCCESS );
}
psa_status_t psa_initialize_key_slots( void )
{
/* Nothing to do: program startup and psa_wipe_all_key_slots() both
* guarantee that the key slots are initialized to all-zero, which
* means that all the key slots are in a valid, empty state. */
global_data.key_slots_initialized = 1;
return( PSA_SUCCESS );
}
void psa_wipe_all_key_slots( void )
{
psa_key_handle_t key;
for( key = 1; key <= PSA_KEY_SLOT_COUNT; key++ )
{
psa_key_slot_t *slot = &global_data.key_slots[key - 1];
(void) psa_wipe_key_slot( slot );
}
global_data.key_slots_initialized = 0;
}
psa_status_t psa_get_empty_key_slot( psa_key_handle_t *handle,
psa_key_slot_t **p_slot )
{
if( ! global_data.key_slots_initialized )
return( PSA_ERROR_BAD_STATE );
for( *handle = PSA_KEY_SLOT_COUNT; *handle != 0; --( *handle ) )
{
*p_slot = &global_data.key_slots[*handle - 1];
if( ! psa_is_key_slot_occupied( *p_slot ) )
return( PSA_SUCCESS );
}
*p_slot = NULL;
return( PSA_ERROR_INSUFFICIENT_MEMORY );
}
#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
static psa_status_t psa_load_persistent_key_into_slot( psa_key_slot_t *slot )
{
psa_status_t status = PSA_SUCCESS;
uint8_t *key_data = NULL;
size_t key_data_length = 0;
status = psa_load_persistent_key( &slot->attr,
&key_data, &key_data_length );
if( status != PSA_SUCCESS )
goto exit;
#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
if( psa_key_lifetime_is_external( slot->attr.lifetime ) )
{
psa_se_key_data_storage_t *data;
if( key_data_length != sizeof( *data ) )
{
status = PSA_ERROR_STORAGE_FAILURE;
goto exit;
}
data = (psa_se_key_data_storage_t *) key_data;
memcpy( &slot->data.se.slot_number, &data->slot_number,
sizeof( slot->data.se.slot_number ) );
memcpy( &slot->attr.bits, &data->bits,
sizeof( slot->attr.bits ) );
}
else
#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
{
status = psa_import_key_into_slot( slot, key_data, key_data_length );
}
exit:
psa_free_persistent_key_data( key_data, key_data_length );
return( status );
}
/** Check whether a key identifier is acceptable.
*
* For backward compatibility, key identifiers that were valid in a
* past released version must remain valid, unless a migration path
* is provided.
*
* \param file_id The key identifier to check.
* \param vendor_ok Nonzero to allow key ids in the vendor range.
* 0 to allow only key ids in the application range.
*
* \return 1 if \p file_id is acceptable, otherwise 0.
*/
static int psa_is_key_id_valid( psa_key_file_id_t file_id,
int vendor_ok )
{
psa_app_key_id_t key_id = PSA_KEY_FILE_GET_KEY_ID( file_id );
if( PSA_KEY_ID_USER_MIN <= key_id && key_id <= PSA_KEY_ID_USER_MAX )
return( 1 );
else if( vendor_ok &&
PSA_KEY_ID_VENDOR_MIN <= key_id &&
key_id <= PSA_KEY_ID_VENDOR_MAX )
return( 1 );
else
return( 0 );
}
#endif /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
psa_status_t psa_validate_key_location( const psa_key_attributes_t *attributes,
psa_se_drv_table_entry_t **p_drv )
{
psa_key_lifetime_t lifetime = psa_get_key_lifetime( attributes );
if ( psa_key_lifetime_is_external( lifetime ) )
{
#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
psa_se_drv_table_entry_t *driver = psa_get_se_driver_entry( lifetime );
if( driver == NULL )
return( PSA_ERROR_INVALID_ARGUMENT );
else
{
if (p_drv != NULL)
*p_drv = driver;
return( PSA_SUCCESS );
}
#else
(void) p_drv;
return( PSA_ERROR_INVALID_ARGUMENT );
#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
}
else
/* Local/internal keys are always valid */
return( PSA_SUCCESS );
}
psa_status_t psa_validate_key_persistence( const psa_key_attributes_t *attributes )
{
psa_key_lifetime_t lifetime = psa_get_key_lifetime( attributes );
if ( PSA_KEY_LIFETIME_IS_VOLATILE( lifetime ) )
{
/* Volatile keys are always supported */
return( PSA_SUCCESS );
}
else
{
/* Persistent keys require storage support */
#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
if( psa_is_key_id_valid( psa_get_key_id( attributes ),
psa_key_lifetime_is_external( lifetime ) ) )
return( PSA_SUCCESS );
else
return( PSA_ERROR_INVALID_ARGUMENT );
#else /* MBEDTLS_PSA_CRYPTO_STORAGE_C */
return( PSA_ERROR_NOT_SUPPORTED );
#endif /* !MBEDTLS_PSA_CRYPTO_STORAGE_C */
}
}
psa_status_t psa_open_key( psa_key_file_id_t id, psa_key_handle_t *handle )
{
#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
psa_status_t status;
psa_key_slot_t *slot;
*handle = 0;
if( ! psa_is_key_id_valid( id, 1 ) )
return( PSA_ERROR_INVALID_ARGUMENT );
status = psa_get_empty_key_slot( handle, &slot );
if( status != PSA_SUCCESS )
return( status );
slot->attr.lifetime = PSA_KEY_LIFETIME_PERSISTENT;
slot->attr.id = id;
status = psa_load_persistent_key_into_slot( slot );
if( status != PSA_SUCCESS )
{
psa_wipe_key_slot( slot );
*handle = 0;
}
return( status );
#else /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
(void) id;
*handle = 0;
return( PSA_ERROR_NOT_SUPPORTED );
#endif /* !defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
}
psa_status_t psa_close_key( psa_key_handle_t handle )
{
psa_status_t status;
psa_key_slot_t *slot;
if( handle == 0 )
return( PSA_SUCCESS );
status = psa_get_key_slot( handle, &slot );
if( status != PSA_SUCCESS )
return( status );
return( psa_wipe_key_slot( slot ) );
}
void mbedtls_psa_get_stats( mbedtls_psa_stats_t *stats )
{
psa_key_handle_t key;
memset( stats, 0, sizeof( *stats ) );
for( key = 1; key <= PSA_KEY_SLOT_COUNT; key++ )
{
const psa_key_slot_t *slot = &global_data.key_slots[key - 1];
if( ! psa_is_key_slot_occupied( slot ) )
{
++stats->empty_slots;
continue;
}
if( slot->attr.lifetime == PSA_KEY_LIFETIME_VOLATILE )
++stats->volatile_slots;
else if( slot->attr.lifetime == PSA_KEY_LIFETIME_PERSISTENT )
{
psa_app_key_id_t id = PSA_KEY_FILE_GET_KEY_ID(slot->attr.id);
++stats->persistent_slots;
if( id > stats->max_open_internal_key_id )
stats->max_open_internal_key_id = id;
}
else
{
psa_app_key_id_t id = PSA_KEY_FILE_GET_KEY_ID(slot->attr.id);
++stats->external_slots;
if( id > stats->max_open_external_key_id )
stats->max_open_external_key_id = id;
}
}
}
#endif /* MBEDTLS_PSA_CRYPTO_C */