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mbedtls/library/psa_crypto_storage.c
Gilles Peskine f65ed6f254 Change key types to a 16-bit encoding 
All key types now have an encoding on 32 bits where the bottom 16 bits
are zero. Change to using 16 bits only.

Keep 32 bits for key types in storage, but move the significant
half-word from the top to the bottom.

Likewise, change EC curve and DH group families from 32 bits out of
which the top 8 and bottom 16 bits are zero, to 8 bits only.

Reorder psa_core_key_attributes_t to avoid padding.
2020-01-31 10:24:21 +01:00

505 lines
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/*
* PSA persistent key storage
*/
/* 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_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 file
* 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( psa_key_file_id_t file_id )
{
#if defined(MBEDTLS_PSA_CRYPTO_KEY_FILE_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) file_id.owner;
return( (uint64_t) unsigned_owner << 32 | file_id.key_id );
#else
/* Use the key id directly as a file name.
* psa_is_key_file_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( file_id );
#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 psa_key_file_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 psa_key_file_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 psa_key_file_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 )
psa_its_remove( data_identifier );
return( status );
}
psa_status_t psa_destroy_persistent_key( const psa_key_file_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 psa_key_file_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;
psa_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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