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mbedtls/library/psa_crypto_se.c
Gilles Peskine e9b55929dc Remove useless platform macro redefinitions: automatic part 
Some source files had code to set mbedtls_xxx aliases when
MBEDTLS_PLATFORM_C is not defined. These aliases are defined unconditionally
by mbedtls/platform.h, so these macro definitions were redundant. Remove
them.

This commit used the following code:
```
perl -i -0777 -pe 's~#if !defined\(MBEDTLS_PLATFORM_C\)\n(#define (mbedtls|MBEDTLS)_.*\n|#include <(stdarg|stddef|stdio|stdlib|string|time)\.h>\n)*#endif.*\n~~mg' $(git grep -l -F '#if !defined(MBEDTLS_PLATFORM_C)')
```

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
2022-09-15 20:34:15 +02:00

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/*
* PSA crypto support for secure element drivers
*/
/*
* 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.
*/
#include "common.h"
#if defined(MBEDTLS_PSA_CRYPTO_SE_C)
#include <assert.h>
#include <stdint.h>
#include <string.h>
#include "psa/crypto_se_driver.h"
#include "psa_crypto_se.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
#include "mbedtls/platform.h"
/****************************************************************/
/* Driver lookup */
/****************************************************************/
/* This structure is identical to psa_drv_se_context_t declared in
* `crypto_se_driver.h`, except that some parts are writable here
* (non-const, or pointer to non-const). */
typedef struct
{
void *persistent_data;
size_t persistent_data_size;
uintptr_t transient_data;
} psa_drv_se_internal_context_t;
struct psa_se_drv_table_entry_s
{
psa_key_location_t location;
const psa_drv_se_t *methods;
union
{
psa_drv_se_internal_context_t internal;
psa_drv_se_context_t context;
} u;
};
static psa_se_drv_table_entry_t driver_table[PSA_MAX_SE_DRIVERS];
psa_se_drv_table_entry_t *psa_get_se_driver_entry(
psa_key_lifetime_t lifetime )
{
size_t i;
psa_key_location_t location = PSA_KEY_LIFETIME_GET_LOCATION( lifetime );
/* In the driver table, location=0 means an entry that isn't used.
* No driver has a location of 0 because it's a reserved value
* (which designates transparent keys). Make sure we never return
* a driver entry for location 0. */
if( location == 0 )
return( NULL );
for( i = 0; i < PSA_MAX_SE_DRIVERS; i++ )
{
if( driver_table[i].location == location )
return( &driver_table[i] );
}
return( NULL );
}
const psa_drv_se_t *psa_get_se_driver_methods(
const psa_se_drv_table_entry_t *driver )
{
return( driver->methods );
}
psa_drv_se_context_t *psa_get_se_driver_context(
psa_se_drv_table_entry_t *driver )
{
return( &driver->u.context );
}
int psa_get_se_driver( psa_key_lifetime_t lifetime,
const psa_drv_se_t **p_methods,
psa_drv_se_context_t **p_drv_context)
{
psa_se_drv_table_entry_t *driver = psa_get_se_driver_entry( lifetime );
if( p_methods != NULL )
*p_methods = ( driver ? driver->methods : NULL );
if( p_drv_context != NULL )
*p_drv_context = ( driver ? &driver->u.context : NULL );
return( driver != NULL );
}
/****************************************************************/
/* Persistent data management */
/****************************************************************/
static psa_status_t psa_get_se_driver_its_file_uid(
const psa_se_drv_table_entry_t *driver,
psa_storage_uid_t *uid )
{
if( driver->location > PSA_MAX_SE_LOCATION )
return( PSA_ERROR_NOT_SUPPORTED );
#if SIZE_MAX > UINT32_MAX
/* ITS file sizes are limited to 32 bits. */
if( driver->u.internal.persistent_data_size > UINT32_MAX )
return( PSA_ERROR_NOT_SUPPORTED );
#endif
/* See the documentation of PSA_CRYPTO_SE_DRIVER_ITS_UID_BASE. */
*uid = PSA_CRYPTO_SE_DRIVER_ITS_UID_BASE + driver->location;
return( PSA_SUCCESS );
}
psa_status_t psa_load_se_persistent_data(
const psa_se_drv_table_entry_t *driver )
{
psa_status_t status;
psa_storage_uid_t uid;
size_t length;
status = psa_get_se_driver_its_file_uid( driver, &uid );
if( status != PSA_SUCCESS )
return( status );
/* Read the amount of persistent data that the driver requests.
* If the data in storage is larger, it is truncated. If the data
* in storage is smaller, silently keep what is already at the end
* of the output buffer. */
/* psa_get_se_driver_its_file_uid ensures that the size_t
* persistent_data_size is in range, but compilers don't know that,
* so cast to reassure them. */
return( psa_its_get( uid, 0,
(uint32_t) driver->u.internal.persistent_data_size,
driver->u.internal.persistent_data,
&length ) );
}
psa_status_t psa_save_se_persistent_data(
const psa_se_drv_table_entry_t *driver )
{
psa_status_t status;
psa_storage_uid_t uid;
status = psa_get_se_driver_its_file_uid( driver, &uid );
if( status != PSA_SUCCESS )
return( status );
/* psa_get_se_driver_its_file_uid ensures that the size_t
* persistent_data_size is in range, but compilers don't know that,
* so cast to reassure them. */
return( psa_its_set( uid,
(uint32_t) driver->u.internal.persistent_data_size,
driver->u.internal.persistent_data,
0 ) );
}
psa_status_t psa_destroy_se_persistent_data( psa_key_location_t location )
{
psa_storage_uid_t uid;
if( location > PSA_MAX_SE_LOCATION )
return( PSA_ERROR_NOT_SUPPORTED );
uid = PSA_CRYPTO_SE_DRIVER_ITS_UID_BASE + location;
return( psa_its_remove( uid ) );
}
psa_status_t psa_find_se_slot_for_key(
const psa_key_attributes_t *attributes,
psa_key_creation_method_t method,
psa_se_drv_table_entry_t *driver,
psa_key_slot_number_t *slot_number )
{
psa_status_t status;
psa_key_location_t key_location =
PSA_KEY_LIFETIME_GET_LOCATION( psa_get_key_lifetime( attributes ) );
/* If the location is wrong, it's a bug in the library. */
if( driver->location != key_location )
return( PSA_ERROR_CORRUPTION_DETECTED );
/* If the driver doesn't support key creation in any way, give up now. */
if( driver->methods->key_management == NULL )
return( PSA_ERROR_NOT_SUPPORTED );
if( psa_get_key_slot_number( attributes, slot_number ) == PSA_SUCCESS )
{
/* The application wants to use a specific slot. Allow it if
* the driver supports it. On a system with isolation,
* the crypto service must check that the application is
* permitted to request this slot. */
psa_drv_se_validate_slot_number_t p_validate_slot_number =
driver->methods->key_management->p_validate_slot_number;
if( p_validate_slot_number == NULL )
return( PSA_ERROR_NOT_SUPPORTED );
status = p_validate_slot_number( &driver->u.context,
driver->u.internal.persistent_data,
attributes, method,
*slot_number );
}
else if( method == PSA_KEY_CREATION_REGISTER )
{
/* The application didn't specify a slot number. This doesn't
* make sense when registering a slot. */
return( PSA_ERROR_INVALID_ARGUMENT );
}
else
{
/* The application didn't tell us which slot to use. Let the driver
* choose. This is the normal case. */
psa_drv_se_allocate_key_t p_allocate =
driver->methods->key_management->p_allocate;
if( p_allocate == NULL )
return( PSA_ERROR_NOT_SUPPORTED );
status = p_allocate( &driver->u.context,
driver->u.internal.persistent_data,
attributes, method,
slot_number );
}
return( status );
}
psa_status_t psa_destroy_se_key( psa_se_drv_table_entry_t *driver,
psa_key_slot_number_t slot_number )
{
psa_status_t status;
psa_status_t storage_status;
/* Normally a missing method would mean that the action is not
* supported. But psa_destroy_key() is not supposed to return
* PSA_ERROR_NOT_SUPPORTED: if you can create a key, you should
* be able to destroy it. The only use case for a driver that
* does not have a way to destroy keys at all is if the keys are
* locked in a read-only state: we can use the keys but not
* destroy them. Hence, if the driver doesn't support destroying
* keys, it's really a lack of permission. */
if( driver->methods->key_management == NULL ||
driver->methods->key_management->p_destroy == NULL )
return( PSA_ERROR_NOT_PERMITTED );
status = driver->methods->key_management->p_destroy(
&driver->u.context,
driver->u.internal.persistent_data,
slot_number );
storage_status = psa_save_se_persistent_data( driver );
return( status == PSA_SUCCESS ? storage_status : status );
}
psa_status_t psa_init_all_se_drivers( void )
{
size_t i;
for( i = 0; i < PSA_MAX_SE_DRIVERS; i++ )
{
psa_se_drv_table_entry_t *driver = &driver_table[i];
if( driver->location == 0 )
continue; /* skipping unused entry */
const psa_drv_se_t *methods = psa_get_se_driver_methods( driver );
if( methods->p_init != NULL )
{
psa_status_t status = methods->p_init(
&driver->u.context,
driver->u.internal.persistent_data,
driver->location );
if( status != PSA_SUCCESS )
return( status );
status = psa_save_se_persistent_data( driver );
if( status != PSA_SUCCESS )
return( status );
}
}
return( PSA_SUCCESS );
}
/****************************************************************/
/* Driver registration */
/****************************************************************/
psa_status_t psa_register_se_driver(
psa_key_location_t location,
const psa_drv_se_t *methods)
{
size_t i;
psa_status_t status;
if( methods->hal_version != PSA_DRV_SE_HAL_VERSION )
return( PSA_ERROR_NOT_SUPPORTED );
/* Driver table entries are 0-initialized. 0 is not a valid driver
* location because it means a transparent key. */
#if defined(static_assert)
static_assert( PSA_KEY_LOCATION_LOCAL_STORAGE == 0,
"Secure element support requires 0 to mean a local key" );
#endif
if( location == PSA_KEY_LOCATION_LOCAL_STORAGE )
return( PSA_ERROR_INVALID_ARGUMENT );
if( location > PSA_MAX_SE_LOCATION )
return( PSA_ERROR_NOT_SUPPORTED );
for( i = 0; i < PSA_MAX_SE_DRIVERS; i++ )
{
if( driver_table[i].location == 0 )
break;
/* Check that location isn't already in use up to the first free
* entry. Since entries are created in order and never deleted,
* there can't be a used entry after the first free entry. */
if( driver_table[i].location == location )
return( PSA_ERROR_ALREADY_EXISTS );
}
if( i == PSA_MAX_SE_DRIVERS )
return( PSA_ERROR_INSUFFICIENT_MEMORY );
driver_table[i].location = location;
driver_table[i].methods = methods;
driver_table[i].u.internal.persistent_data_size =
methods->persistent_data_size;
if( methods->persistent_data_size != 0 )
{
driver_table[i].u.internal.persistent_data =
mbedtls_calloc( 1, methods->persistent_data_size );
if( driver_table[i].u.internal.persistent_data == NULL )
{
status = PSA_ERROR_INSUFFICIENT_MEMORY;
goto error;
}
/* Load the driver's persistent data. On first use, the persistent
* data does not exist in storage, and is initialized to
* all-bits-zero by the calloc call just above. */
status = psa_load_se_persistent_data( &driver_table[i] );
if( status != PSA_SUCCESS && status != PSA_ERROR_DOES_NOT_EXIST )
goto error;
}
return( PSA_SUCCESS );
error:
memset( &driver_table[i], 0, sizeof( driver_table[i] ) );
return( status );
}
void psa_unregister_all_se_drivers( void )
{
size_t i;
for( i = 0; i < PSA_MAX_SE_DRIVERS; i++ )
{
if( driver_table[i].u.internal.persistent_data != NULL )
mbedtls_free( driver_table[i].u.internal.persistent_data );
}
memset( driver_table, 0, sizeof( driver_table ) );
}
/****************************************************************/
/* The end */
/****************************************************************/
#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
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