41e50d26ea
The flag to mark key slots as allocated was introduced to mark slots that are claimed and in use, but do not have key material yet, at a time when creating a key used several API functions: allocate a slot, then progressively set its metadata, and finally create the key material. Now that all of these steps are combined into a single API function call, the notion of allocated-but-not-filled slot is no longer relevant. So remove the corresponding flag. A slot is occupied iff there is a key in it. (For a key in a secure element, the key material is not present, but the slot contains the key metadata.) This key must have a type which is nonzero, so use this as an indicator that a slot is in use.
294 lines
8.7 KiB
C
294 lines
8.7 KiB
C
/*
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* PSA crypto layer on top of Mbed TLS crypto
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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.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_C)
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#include "psa_crypto_service_integration.h"
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#include "psa/crypto.h"
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#include "psa_crypto_core.h"
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#include "psa_crypto_slot_management.h"
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#include "psa_crypto_storage.h"
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#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
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#include "psa_crypto_se.h"
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#endif
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#include <stdlib.h>
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#include <string.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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#define ARRAY_LENGTH( array ) ( sizeof( array ) / sizeof( *( array ) ) )
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typedef struct
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{
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psa_key_slot_t key_slots[PSA_KEY_SLOT_COUNT];
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unsigned key_slots_initialized : 1;
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} psa_global_data_t;
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static psa_global_data_t global_data;
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/* Access a key slot at the given handle. The handle of a key slot is
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* the index of the slot in the global slot array, plus one so that handles
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* start at 1 and not 0. */
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psa_status_t psa_get_key_slot( psa_key_handle_t handle,
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psa_key_slot_t **p_slot )
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{
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psa_key_slot_t *slot = NULL;
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if( ! global_data.key_slots_initialized )
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return( PSA_ERROR_BAD_STATE );
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/* 0 is not a valid handle under any circumstance. This
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* implementation provides slots number 1 to N where N is the
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* number of available slots. */
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if( handle == 0 || handle > ARRAY_LENGTH( global_data.key_slots ) )
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return( PSA_ERROR_INVALID_HANDLE );
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slot = &global_data.key_slots[handle - 1];
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/* If the slot isn't occupied, the handle is invalid. */
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if( ! psa_is_key_slot_occupied( slot ) )
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return( PSA_ERROR_INVALID_HANDLE );
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*p_slot = slot;
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return( PSA_SUCCESS );
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}
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psa_status_t psa_initialize_key_slots( void )
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{
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/* Nothing to do: program startup and psa_wipe_all_key_slots() both
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* guarantee that the key slots are initialized to all-zero, which
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* means that all the key slots are in a valid, empty state. */
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global_data.key_slots_initialized = 1;
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return( PSA_SUCCESS );
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}
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void psa_wipe_all_key_slots( void )
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{
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psa_key_handle_t key;
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for( key = 1; key <= PSA_KEY_SLOT_COUNT; key++ )
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{
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psa_key_slot_t *slot = &global_data.key_slots[key - 1];
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(void) psa_wipe_key_slot( slot );
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}
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global_data.key_slots_initialized = 0;
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}
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psa_status_t psa_internal_allocate_key_slot( psa_key_handle_t *handle,
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psa_key_slot_t **p_slot )
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{
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if( ! global_data.key_slots_initialized )
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return( PSA_ERROR_BAD_STATE );
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for( *handle = PSA_KEY_SLOT_COUNT; *handle != 0; --( *handle ) )
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{
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*p_slot = &global_data.key_slots[*handle - 1];
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if( ! psa_is_key_slot_occupied( *p_slot ) )
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return( PSA_SUCCESS );
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}
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*p_slot = NULL;
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return( PSA_ERROR_INSUFFICIENT_MEMORY );
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}
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#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
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static psa_status_t psa_load_persistent_key_into_slot( psa_key_slot_t *slot )
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{
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psa_status_t status = PSA_SUCCESS;
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uint8_t *key_data = NULL;
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size_t key_data_length = 0;
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status = psa_load_persistent_key( &slot->attr,
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&key_data, &key_data_length );
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if( status != PSA_SUCCESS )
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goto exit;
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#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
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if( psa_key_lifetime_is_external( slot->attr.lifetime ) )
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{
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psa_se_key_data_storage_t *data;
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if( key_data_length != sizeof( *data ) )
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{
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status = PSA_ERROR_STORAGE_FAILURE;
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goto exit;
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}
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data = (psa_se_key_data_storage_t *) key_data;
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memcpy( &slot->data.se.slot_number, &data->slot_number,
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sizeof( slot->data.se.slot_number ) );
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memcpy( &slot->attr.bits, &data->bits,
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sizeof( slot->attr.bits ) );
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}
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else
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#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
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{
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status = psa_import_key_into_slot( slot, key_data, key_data_length );
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}
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exit:
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psa_free_persistent_key_data( key_data, key_data_length );
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return( status );
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}
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/** Check whether a key identifier is acceptable.
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*
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* For backward compatibility, key identifiers that were valid in a
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* past released version must remain valid, unless a migration path
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* is provided.
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*
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* \param file_id The key identifier to check.
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* \param vendor_ok Nonzero to allow key ids in the vendor range.
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* 0 to allow only key ids in the application range.
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*
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* \return 1 if \p file_id is acceptable, otherwise 0.
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*/
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static int psa_is_key_id_valid( psa_key_file_id_t file_id,
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int vendor_ok )
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{
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psa_app_key_id_t key_id = PSA_KEY_FILE_GET_KEY_ID( file_id );
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if( PSA_KEY_ID_USER_MIN <= key_id && key_id <= PSA_KEY_ID_USER_MAX )
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return( 1 );
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else if( vendor_ok &&
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PSA_KEY_ID_VENDOR_MIN <= key_id &&
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key_id <= PSA_KEY_ID_VENDOR_MAX )
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return( 1 );
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else
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return( 0 );
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}
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#endif /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
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psa_status_t psa_validate_persistent_key_parameters(
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psa_key_lifetime_t lifetime,
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psa_key_file_id_t id,
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psa_se_drv_table_entry_t **p_drv,
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int creating )
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{
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if( p_drv != NULL )
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*p_drv = NULL;
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#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
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if( psa_key_lifetime_is_external( lifetime ) )
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{
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*p_drv = psa_get_se_driver_entry( lifetime );
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if( *p_drv == NULL )
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return( PSA_ERROR_INVALID_ARGUMENT );
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}
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else
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#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
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if( lifetime != PSA_KEY_LIFETIME_PERSISTENT )
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return( PSA_ERROR_INVALID_ARGUMENT );
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#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
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if( ! psa_is_key_id_valid( id, ! creating ) )
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return( PSA_ERROR_INVALID_ARGUMENT );
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return( PSA_SUCCESS );
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#else /* MBEDTLS_PSA_CRYPTO_STORAGE_C */
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(void) id;
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(void) creating;
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return( PSA_ERROR_NOT_SUPPORTED );
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#endif /* !MBEDTLS_PSA_CRYPTO_STORAGE_C */
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}
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psa_status_t psa_open_key( psa_key_file_id_t id, psa_key_handle_t *handle )
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{
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#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
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psa_status_t status;
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psa_key_slot_t *slot;
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*handle = 0;
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status = psa_validate_persistent_key_parameters(
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PSA_KEY_LIFETIME_PERSISTENT, id, NULL, 0 );
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if( status != PSA_SUCCESS )
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return( status );
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status = psa_internal_allocate_key_slot( handle, &slot );
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if( status != PSA_SUCCESS )
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return( status );
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slot->attr.lifetime = PSA_KEY_LIFETIME_PERSISTENT;
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slot->attr.id = id;
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status = psa_load_persistent_key_into_slot( slot );
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if( status != PSA_SUCCESS )
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{
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psa_wipe_key_slot( slot );
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*handle = 0;
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}
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return( status );
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#else /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
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(void) id;
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*handle = 0;
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return( PSA_ERROR_NOT_SUPPORTED );
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#endif /* !defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */
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}
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psa_status_t psa_close_key( psa_key_handle_t handle )
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{
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psa_status_t status;
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psa_key_slot_t *slot;
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status = psa_get_key_slot( handle, &slot );
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if( status != PSA_SUCCESS )
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return( status );
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return( psa_wipe_key_slot( slot ) );
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}
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void mbedtls_psa_get_stats( mbedtls_psa_stats_t *stats )
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{
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psa_key_handle_t key;
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memset( stats, 0, sizeof( *stats ) );
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for( key = 1; key <= PSA_KEY_SLOT_COUNT; key++ )
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{
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const psa_key_slot_t *slot = &global_data.key_slots[key - 1];
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if( ! psa_is_key_slot_occupied( slot ) )
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{
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++stats->empty_slots;
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continue;
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}
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if( slot->attr.lifetime == PSA_KEY_LIFETIME_VOLATILE )
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++stats->volatile_slots;
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else if( slot->attr.lifetime == PSA_KEY_LIFETIME_PERSISTENT )
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{
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++stats->persistent_slots;
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if( slot->attr.id > stats->max_open_internal_key_id )
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stats->max_open_internal_key_id = slot->attr.id;
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}
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else
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{
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++stats->external_slots;
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if( slot->attr.id > stats->max_open_external_key_id )
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stats->max_open_external_key_id = slot->attr.id;
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}
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}
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}
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#endif /* MBEDTLS_PSA_CRYPTO_C */
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