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mbedtls/library/psa_crypto_storage.c
Ronald Cron 71016a9ea7 psa: Rename psa_key_file_id_t to mbedtls_svc_key_id_t 
With PSA crypto v1.0.0, a volatile key identifier may
contain a owner identifier but no file is associated
to it. Thus rename the type psa_key_file_id_t to
mbedtls_svc_key_id_t to avoid a direct link with a
file when a key identifier involves an owner
identifier.

The new type name is prefixed by mbedtls to highlight
that the type is specific to Mbed TLS implementation
and not defined in the PSA Cryptography API
specification.

The svc in the type name stands for service as this
is the key identifier type from the point of view of
the service providing the Cryptography services.
The service can be completely provided by the present
library or partially in case of a multi-client service.

As a consequence rename as well:
. MBEDTLS_PSA_CRYPTO_KEY_FILE_ID_ENCODES_OWNER to
  MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER
. PSA_KEY_ID_INIT to MBEDTLS_SVC_KEY_ID_INIT
. PSA_KEY_FILE_GET_KEY_ID to MBEDTLS_SVC_KEY_ID_GET_KEY_ID
. psa_key_file_id_make to mbedtls_svc_key_id_make

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
2020-09-02 14:27:07 +02:00

509 lines
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/*
* PSA persistent key storage
*/
/*
* Copyright The Mbed TLS Contributors
* 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.
*/
#if defined(MBEDTLS_CONFIG_FILE)
#include MBEDTLS_CONFIG_FILE
#else
#include "mbedtls/config.h"
#endif
#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
#include <stdlib.h>
#include <string.h>
#include "psa_crypto_service_integration.h"
#include "psa/crypto.h"
#include "psa_crypto_storage.h"
#include "mbedtls/platform_util.h"
#if defined(MBEDTLS_PSA_ITS_FILE_C)
#include "psa_crypto_its.h"
#else /* Native ITS implementation */
#include "psa/error.h"
#include "psa/internal_trusted_storage.h"
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdlib.h>
#define mbedtls_calloc calloc
#define mbedtls_free free
#endif
/****************************************************************/
/* Key storage */
/****************************************************************/
/* Determine a file name (ITS file identifier) for the given key identifier.
* The file name must be distinct from any file that is used for a purpose
* other than storing a key. Currently, the only such file is the random seed
* file whose name is PSA_CRYPTO_ITS_RANDOM_SEED_UID and whose value is
* 0xFFFFFF52. */
static psa_storage_uid_t psa_its_identifier_of_slot( mbedtls_svc_key_id_t key )
{
#if defined(MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER) && \
defined(PSA_CRYPTO_SECURE)
/* Encode the owner in the upper 32 bits. This means that if
* owner values are nonzero (as they are on a PSA platform),
* no key file will ever have a value less than 0x100000000, so
* the whole range 0..0xffffffff is available for non-key files. */
uint32_t unsigned_owner = (uint32_t) key.owner;
return( (uint64_t) unsigned_owner << 32 | key.key_id );
#else
/* Use the key id directly as a file name.
* psa_is_key_id_valid() in psa_crypto_slot_management.c
* is responsible for ensuring that key identifiers do not have a
* value that is reserved for non-key files. */
return( key );
#endif
}
/**
* \brief Load persistent data for the given key slot number.
*
* This function reads data from a storage backend and returns the data in a
* buffer.
*
* \param key Persistent identifier of the key to be loaded. This
* should be an occupied storage location.
* \param[out] data Buffer where the data is to be written.
* \param data_size Size of the \c data buffer in bytes.
*
* \retval PSA_SUCCESS
* \retval PSA_ERROR_STORAGE_FAILURE
* \retval PSA_ERROR_DOES_NOT_EXIST
*/
static psa_status_t psa_crypto_storage_load(
const mbedtls_svc_key_id_t key, uint8_t *data, size_t data_size )
{
psa_status_t status;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot( key );
struct psa_storage_info_t data_identifier_info;
size_t data_length = 0;
status = psa_its_get_info( data_identifier, &data_identifier_info );
if( status != PSA_SUCCESS )
return( status );
status = psa_its_get( data_identifier, 0, (uint32_t) data_size, data, &data_length );
if( data_size != data_length )
return( PSA_ERROR_STORAGE_FAILURE );
return( status );
}
int psa_is_key_present_in_storage( const mbedtls_svc_key_id_t key )
{
psa_status_t ret;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot( key );
struct psa_storage_info_t data_identifier_info;
ret = psa_its_get_info( data_identifier, &data_identifier_info );
if( ret == PSA_ERROR_DOES_NOT_EXIST )
return( 0 );
return( 1 );
}
/**
* \brief Store persistent data for the given key slot number.
*
* This function stores the given data buffer to a persistent storage.
*
* \param key Persistent identifier of the key to be stored. This
* should be an unoccupied storage location.
* \param[in] data Buffer containing the data to be stored.
* \param data_length The number of bytes
* that make up the data.
*
* \retval PSA_SUCCESS
* \retval PSA_ERROR_INSUFFICIENT_STORAGE
* \retval PSA_ERROR_STORAGE_FAILURE
* \retval PSA_ERROR_ALREADY_EXISTS
*/
static psa_status_t psa_crypto_storage_store( const mbedtls_svc_key_id_t key,
const uint8_t *data,
size_t data_length )
{
psa_status_t status;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot( key );
struct psa_storage_info_t data_identifier_info;
if( psa_is_key_present_in_storage( key ) == 1 )
return( PSA_ERROR_ALREADY_EXISTS );
status = psa_its_set( data_identifier, (uint32_t) data_length, data, 0 );
if( status != PSA_SUCCESS )
{
return( PSA_ERROR_STORAGE_FAILURE );
}
status = psa_its_get_info( data_identifier, &data_identifier_info );
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 )
{
/* Remove the file in case we managed to create it but something
* went wrong. It's ok if the file doesn't exist. If the file exists
* but the removal fails, we're already reporting an error so there's
* nothing else we can do. */
(void) psa_its_remove( data_identifier );
}
return( status );
}
psa_status_t psa_destroy_persistent_key( const mbedtls_svc_key_id_t key )
{
psa_status_t ret;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot( key );
struct psa_storage_info_t data_identifier_info;
ret = psa_its_get_info( data_identifier, &data_identifier_info );
if( ret == PSA_ERROR_DOES_NOT_EXIST )
return( PSA_SUCCESS );
if( psa_its_remove( data_identifier ) != PSA_SUCCESS )
return( PSA_ERROR_STORAGE_FAILURE );
ret = psa_its_get_info( data_identifier, &data_identifier_info );
if( ret != PSA_ERROR_DOES_NOT_EXIST )
return( PSA_ERROR_STORAGE_FAILURE );
return( PSA_SUCCESS );
}
/**
* \brief Get data length for given key slot number.
*
* \param key Persistent identifier whose stored data length
* is to be obtained.
* \param[out] data_length The number of bytes that make up the data.
*
* \retval PSA_SUCCESS
* \retval PSA_ERROR_STORAGE_FAILURE
*/
static psa_status_t psa_crypto_storage_get_data_length(
const mbedtls_svc_key_id_t key,
size_t *data_length )
{
psa_status_t status;
psa_storage_uid_t data_identifier = psa_its_identifier_of_slot( key );
struct psa_storage_info_t data_identifier_info;
status = psa_its_get_info( data_identifier, &data_identifier_info );
if( status != PSA_SUCCESS )
return( status );
*data_length = (size_t) data_identifier_info.size;
return( PSA_SUCCESS );
}
/*
* 32-bit integer manipulation macros (little endian)
*/
#ifndef GET_UINT32_LE
#define GET_UINT32_LE( n, b, i ) \
{ \
(n) = ( (uint32_t) (b)[(i) ] ) \
| ( (uint32_t) (b)[(i) + 1] << 8 ) \
| ( (uint32_t) (b)[(i) + 2] << 16 ) \
| ( (uint32_t) (b)[(i) + 3] << 24 ); \
}
#endif
#ifndef PUT_UINT32_LE
#define PUT_UINT32_LE( n, b, i ) \
{ \
(b)[(i) ] = (unsigned char) ( ( (n) ) & 0xFF ); \
(b)[(i) + 1] = (unsigned char) ( ( (n) >> 8 ) & 0xFF ); \
(b)[(i) + 2] = (unsigned char) ( ( (n) >> 16 ) & 0xFF ); \
(b)[(i) + 3] = (unsigned char) ( ( (n) >> 24 ) & 0xFF ); \
}
#endif
/**
* Persistent key storage magic header.
*/
#define PSA_KEY_STORAGE_MAGIC_HEADER "PSA\0KEY"
#define PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH ( sizeof( PSA_KEY_STORAGE_MAGIC_HEADER ) )
typedef struct {
uint8_t magic[PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH];
uint8_t version[4];
uint8_t lifetime[sizeof( psa_key_lifetime_t )];
uint8_t type[4]; /* Size=4 for a 2-byte type to keep the structure more
* regular and aligned and to make potential future
* extensibility easier. */
uint8_t policy[sizeof( psa_key_policy_t )];
uint8_t data_len[4];
uint8_t key_data[];
} psa_persistent_key_storage_format;
void psa_format_key_data_for_storage( const uint8_t *data,
const size_t data_length,
const psa_core_key_attributes_t *attr,
uint8_t *storage_data )
{
psa_persistent_key_storage_format *storage_format =
(psa_persistent_key_storage_format *) storage_data;
memcpy( storage_format->magic, PSA_KEY_STORAGE_MAGIC_HEADER, PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH );
PUT_UINT32_LE( 0, storage_format->version, 0 );
PUT_UINT32_LE( attr->lifetime, storage_format->lifetime, 0 );
PUT_UINT32_LE( (uint32_t) attr->type, storage_format->type, 0 );
PUT_UINT32_LE( attr->policy.usage, storage_format->policy, 0 );
PUT_UINT32_LE( attr->policy.alg, storage_format->policy, sizeof( uint32_t ) );
PUT_UINT32_LE( attr->policy.alg2, storage_format->policy, 2 * sizeof( uint32_t ) );
PUT_UINT32_LE( data_length, storage_format->data_len, 0 );
memcpy( storage_format->key_data, data, data_length );
}
static psa_status_t check_magic_header( const uint8_t *data )
{
if( memcmp( data, PSA_KEY_STORAGE_MAGIC_HEADER,
PSA_KEY_STORAGE_MAGIC_HEADER_LENGTH ) != 0 )
return( PSA_ERROR_STORAGE_FAILURE );
return( PSA_SUCCESS );
}
psa_status_t psa_parse_key_data_from_storage( const uint8_t *storage_data,
size_t storage_data_length,
uint8_t **key_data,
size_t *key_data_length,
psa_core_key_attributes_t *attr )
{
psa_status_t status;
const psa_persistent_key_storage_format *storage_format =
(const psa_persistent_key_storage_format *)storage_data;
uint32_t version;
uint32_t type;
if( storage_data_length < sizeof(*storage_format) )
return( PSA_ERROR_STORAGE_FAILURE );
status = check_magic_header( storage_data );
if( status != PSA_SUCCESS )
return( status );
GET_UINT32_LE( version, storage_format->version, 0 );
if( version != 0 )
return( PSA_ERROR_STORAGE_FAILURE );
GET_UINT32_LE( *key_data_length, storage_format->data_len, 0 );
if( *key_data_length > ( storage_data_length - sizeof(*storage_format) ) ||
*key_data_length > PSA_CRYPTO_MAX_STORAGE_SIZE )
return( PSA_ERROR_STORAGE_FAILURE );
if( *key_data_length == 0 )
{
*key_data = NULL;
}
else
{
*key_data = mbedtls_calloc( 1, *key_data_length );
if( *key_data == NULL )
return( PSA_ERROR_INSUFFICIENT_MEMORY );
memcpy( *key_data, storage_format->key_data, *key_data_length );
}
GET_UINT32_LE( attr->lifetime, storage_format->lifetime, 0 );
GET_UINT32_LE( type, storage_format->type, 0 );
if( type <= (psa_key_type_t) -1 )
attr->type = (psa_key_type_t) type;
else
return( PSA_ERROR_STORAGE_FAILURE );
GET_UINT32_LE( attr->policy.usage, storage_format->policy, 0 );
GET_UINT32_LE( attr->policy.alg, storage_format->policy, sizeof( uint32_t ) );
GET_UINT32_LE( attr->policy.alg2, storage_format->policy, 2 * sizeof( uint32_t ) );
return( PSA_SUCCESS );
}
psa_status_t psa_save_persistent_key( const psa_core_key_attributes_t *attr,
const uint8_t *data,
const size_t data_length )
{
size_t storage_data_length;
uint8_t *storage_data;
psa_status_t status;
if( data_length > PSA_CRYPTO_MAX_STORAGE_SIZE )
return PSA_ERROR_INSUFFICIENT_STORAGE;
storage_data_length = data_length + sizeof( psa_persistent_key_storage_format );
storage_data = mbedtls_calloc( 1, storage_data_length );
if( storage_data == NULL )
return( PSA_ERROR_INSUFFICIENT_MEMORY );
psa_format_key_data_for_storage( data, data_length, attr, storage_data );
status = psa_crypto_storage_store( attr->id,
storage_data, storage_data_length );
mbedtls_free( storage_data );
return( status );
}
void psa_free_persistent_key_data( uint8_t *key_data, size_t key_data_length )
{
if( key_data != NULL )
{
mbedtls_platform_zeroize( key_data, key_data_length );
}
mbedtls_free( key_data );
}
psa_status_t psa_load_persistent_key( psa_core_key_attributes_t *attr,
uint8_t **data,
size_t *data_length )
{
psa_status_t status = PSA_SUCCESS;
uint8_t *loaded_data;
size_t storage_data_length = 0;
mbedtls_svc_key_id_t key = attr->id;
status = psa_crypto_storage_get_data_length( key, &storage_data_length );
if( status != PSA_SUCCESS )
return( status );
loaded_data = mbedtls_calloc( 1, storage_data_length );
if( loaded_data == NULL )
return( PSA_ERROR_INSUFFICIENT_MEMORY );
status = psa_crypto_storage_load( key, loaded_data, storage_data_length );
if( status != PSA_SUCCESS )
goto exit;
status = psa_parse_key_data_from_storage( loaded_data, storage_data_length,
data, data_length, attr );
exit:
mbedtls_free( loaded_data );
return( status );
}
/****************************************************************/
/* Transactions */
/****************************************************************/
#if defined(PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS)
psa_crypto_transaction_t psa_crypto_transaction;
psa_status_t psa_crypto_save_transaction( void )
{
struct psa_storage_info_t p_info;
psa_status_t status;
status = psa_its_get_info( PSA_CRYPTO_ITS_TRANSACTION_UID, &p_info );
if( status == PSA_SUCCESS )
{
/* This shouldn't happen: we're trying to start a transaction while
* there is still a transaction that hasn't been replayed. */
return( PSA_ERROR_CORRUPTION_DETECTED );
}
else if( status != PSA_ERROR_DOES_NOT_EXIST )
return( status );
return( psa_its_set( PSA_CRYPTO_ITS_TRANSACTION_UID,
sizeof( psa_crypto_transaction ),
&psa_crypto_transaction,
0 ) );
}
psa_status_t psa_crypto_load_transaction( void )
{
psa_status_t status;
size_t length;
status = psa_its_get( PSA_CRYPTO_ITS_TRANSACTION_UID, 0,
sizeof( psa_crypto_transaction ),
&psa_crypto_transaction, &length );
if( status != PSA_SUCCESS )
return( status );
if( length != sizeof( psa_crypto_transaction ) )
return( PSA_ERROR_STORAGE_FAILURE );
return( PSA_SUCCESS );
}
psa_status_t psa_crypto_stop_transaction( void )
{
psa_status_t status = psa_its_remove( PSA_CRYPTO_ITS_TRANSACTION_UID );
/* Whether or not updating the storage succeeded, the transaction is
* finished now. It's too late to go back, so zero out the in-memory
* data. */
memset( &psa_crypto_transaction, 0, sizeof( psa_crypto_transaction ) );
return( status );
}
#endif /* PSA_CRYPTO_STORAGE_HAS_TRANSACTIONS */
/****************************************************************/
/* Random generator state */
/****************************************************************/
#if defined(MBEDTLS_PSA_INJECT_ENTROPY)
psa_status_t mbedtls_psa_storage_inject_entropy( const unsigned char *seed,
size_t seed_size )
{
psa_status_t status;
struct psa_storage_info_t p_info;
status = psa_its_get_info( PSA_CRYPTO_ITS_RANDOM_SEED_UID, &p_info );
if( PSA_ERROR_DOES_NOT_EXIST == status ) /* No seed exists */
{
status = psa_its_set( PSA_CRYPTO_ITS_RANDOM_SEED_UID, seed_size, seed, 0 );
}
else if( PSA_SUCCESS == status )
{
/* You should not be here. Seed needs to be injected only once */
status = PSA_ERROR_NOT_PERMITTED;
}
return( status );
}
#endif /* MBEDTLS_PSA_INJECT_ENTROPY */
/****************************************************************/
/* The end */
/****************************************************************/
#endif /* MBEDTLS_PSA_CRYPTO_STORAGE_C */
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