SE keys: implement persistent storage

For a key in a secure element, persist the key slot.

This is implemented in the nominal case. Failures may not be handled
properly.
This commit is contained in:
Gilles Peskine 2019-07-23 16:13:14 +02:00
parent 0e8d495bd9
commit 1df83d4f5b
4 changed files with 80 additions and 18 deletions

View file

@ -1469,20 +1469,30 @@ static psa_status_t psa_finish_key_creation(
(void) driver; (void) driver;
#if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) #if defined(MBEDTLS_PSA_CRYPTO_STORAGE_C)
if( slot->lifetime == PSA_KEY_LIFETIME_PERSISTENT ) if( slot->lifetime != PSA_KEY_LIFETIME_VOLATILE )
{ {
uint8_t *buffer = NULL; uint8_t *buffer = NULL;
size_t buffer_size = 0; size_t buffer_size = 0;
size_t length; size_t length = 0;
buffer_size = PSA_KEY_EXPORT_MAX_SIZE( slot->type, #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
psa_get_key_slot_bits( slot ) ); if( driver != NULL )
buffer = mbedtls_calloc( 1, buffer_size ); {
if( buffer == NULL && buffer_size != 0 ) buffer = (uint8_t*) &slot->data.se.slot_number;
return( PSA_ERROR_INSUFFICIENT_MEMORY ); length = sizeof( slot->data.se.slot_number );
status = psa_internal_export_key( slot, }
buffer, buffer_size, &length, else
0 ); #endif /* MBEDTLS_PSA_CRYPTO_SE_C */
{
buffer_size = PSA_KEY_EXPORT_MAX_SIZE( slot->type,
psa_get_key_slot_bits( slot ) );
buffer = mbedtls_calloc( 1, buffer_size );
if( buffer == NULL && buffer_size != 0 )
return( PSA_ERROR_INSUFFICIENT_MEMORY );
status = psa_internal_export_key( slot,
buffer, buffer_size, &length,
0 );
}
if( status == PSA_SUCCESS ) if( status == PSA_SUCCESS )
{ {
@ -1491,9 +1501,14 @@ static psa_status_t psa_finish_key_creation(
status = psa_save_persistent_key( &attributes, buffer, length ); status = psa_save_persistent_key( &attributes, buffer, length );
} }
if( buffer_size != 0 ) #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
mbedtls_platform_zeroize( buffer, buffer_size ); if( driver == NULL )
mbedtls_free( buffer ); #endif /* MBEDTLS_PSA_CRYPTO_SE_C */
{
if( buffer_size != 0 )
mbedtls_platform_zeroize( buffer, buffer_size );
mbedtls_free( buffer );
}
} }
#endif /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */ #endif /* defined(MBEDTLS_PSA_CRYPTO_STORAGE_C) */

View file

@ -131,10 +131,28 @@ static psa_status_t psa_load_persistent_key_into_slot( psa_key_slot_t *p_slot )
&key_data, &key_data_length ); &key_data, &key_data_length );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
goto exit; goto exit;
p_slot->lifetime = psa_get_key_lifetime( &attributes );
p_slot->type = psa_get_key_type( &attributes ); p_slot->type = psa_get_key_type( &attributes );
p_slot->policy = attributes.policy; p_slot->policy = attributes.policy;
status = psa_import_key_into_slot( p_slot,
key_data, key_data_length ); #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
if( psa_key_lifetime_is_external( p_slot->lifetime ) )
{
if( key_data_length != sizeof( p_slot->data.se.slot_number ) )
{
status = PSA_ERROR_STORAGE_FAILURE;
goto exit;
}
memcpy( &p_slot->data.se.slot_number, key_data,
sizeof( p_slot->data.se.slot_number ) );
}
else
#endif /* MBEDTLS_PSA_CRYPTO_SE_C */
{
status = psa_import_key_into_slot( p_slot,
key_data, key_data_length );
}
exit: exit:
psa_free_persistent_key_data( key_data, key_data_length ); psa_free_persistent_key_data( key_data, key_data_length );
return( status ); return( status );

View file

@ -28,7 +28,13 @@ Register SE driver: maximum number of drivers
register_max: register_max:
Key creation smoke test (p_allocate allows all slots) Key creation smoke test (p_allocate allows all slots)
key_creation_import_export:0 key_creation_import_export:0:0
Key creation smoke test (p_allocate allows 1 slot) Key creation smoke test (p_allocate allows 1 slot)
key_creation_import_export:ARRAY_LENGTH( ram_slots ) - 1 key_creation_import_export:ARRAY_LENGTH( ram_slots ) - 1:0
Key creation smoke test, check after restart (slot 0)
key_creation_import_export:0:1
Key creation smoke test, check after restart (slot 3)
key_creation_import_export:3:1

View file

@ -3,6 +3,7 @@
#include "psa/crypto_se_driver.h" #include "psa/crypto_se_driver.h"
#include "psa_crypto_se.h" #include "psa_crypto_se.h"
#include "psa_crypto_storage.h"
/** The minimum valid lifetime value for a secure element driver. */ /** The minimum valid lifetime value for a secure element driver. */
#define MIN_DRIVER_LIFETIME 2 #define MIN_DRIVER_LIFETIME 2
@ -115,6 +116,18 @@ psa_status_t ram_allocate( psa_drv_se_context_t *context,
return( PSA_ERROR_INSUFFICIENT_STORAGE ); return( PSA_ERROR_INSUFFICIENT_STORAGE );
} }
#define MAX_KEY_ID_FOR_TEST 10
void psa_purge_storage( void )
{
psa_key_id_t i;
/* The tests may have potentially created key ids from 1 to
* MAX_KEY_ID_FOR_TEST. In addition, run the destroy function on key id
* 0, which file-based storage uses as a temporary file. */
for( i = 0; i <= MAX_KEY_ID_FOR_TEST; i++ )
psa_destroy_persistent_key( i );
psa_crypto_stop_transaction( );
}
/* END_HEADER */ /* END_HEADER */
/* BEGIN_DEPENDENCIES /* BEGIN_DEPENDENCIES
@ -188,7 +201,7 @@ exit:
/* END_CASE */ /* END_CASE */
/* BEGIN_CASE */ /* BEGIN_CASE */
void key_creation_import_export( int min_slot ) void key_creation_import_export( int min_slot, int restart )
{ {
psa_drv_se_t driver; psa_drv_se_t driver;
psa_drv_se_key_management_t key_management; psa_drv_se_key_management_t key_management;
@ -223,6 +236,15 @@ void key_creation_import_export( int min_slot )
key_material, sizeof( key_material ), key_material, sizeof( key_material ),
&handle ) ); &handle ) );
/* Maybe restart, to check that the information is saved correctly. */
if( restart )
{
mbedtls_psa_crypto_free( );
PSA_ASSERT( psa_register_se_driver( lifetime, &driver ) );
PSA_ASSERT( psa_crypto_init( ) );
PSA_ASSERT( psa_open_key( id, &handle ) );
}
/* Test that the key was created in the expected slot. */ /* Test that the key was created in the expected slot. */
TEST_ASSERT( ram_slots[min_slot].type == PSA_KEY_TYPE_RAW_DATA ); TEST_ASSERT( ram_slots[min_slot].type == PSA_KEY_TYPE_RAW_DATA );
@ -240,5 +262,6 @@ void key_creation_import_export( int min_slot )
exit: exit:
PSA_DONE( ); PSA_DONE( );
ram_slots_reset( ); ram_slots_reset( );
psa_purge_storage( );
} }
/* END_CASE */ /* END_CASE */