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psa: driver wrapper: Clarify the scope of and rename get_expected_key_size

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Restrict the scope of get_expected_key_size to
generation of key in a secure element or
cryptoprocessor without storage.

For transparent driver, the key buffer size calculation is
for the time being moved to psa_driver_wrapper_generate_key
and will eventually be done by psa_get_key_buffer_size.

Rename the function to get_key_buffer_size to
align its naming with that of psa_get_key_buffer_size.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This commit is contained in:
Ronald Cron 2020-12-05 18:47:56 +01:00
parent 9cca31654c
commit 31216284e1
1 changed files with 37 additions and 31 deletions
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68
library/psa_crypto_driver_wrappers.c
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@ -239,61 +239,56 @@ psa_status_t psa_driver_wrapper_verify_hash( psa_key_slot_t *slot,
}
#if defined(PSA_CRYPTO_ACCELERATOR_DRIVER_PRESENT)
/** Calculate the size to allocate for buffering a key with given attributes.
/** Get the key buffer size for the key material of a generated key in the
* case of an opaque driver without storage.
*
* This function provides a way to get the expected size for storing a key with
* the given attributes. This will be the size of the export representation for
* cleartext keys, and a driver-defined size for keys stored by opaque drivers.
*
* \param[in] attributes The key attribute structure of the key to store.
* \param[out] expected_size On success, a byte size large enough to contain
* the declared key.
* \param[in] attributes The key attributes.
* \param[out] key_buffer_size Minimum buffer size to contain the key material
*
* \retval #PSA_SUCCESS
* The minimum size for a buffer to contain the key material has been
* returned successfully.
* \retval #PSA_ERROR_INVALID_ARGUMENT
* The size in bits of the key is not valid.
* \retval #PSA_ERROR_NOT_SUPPORTED
* The type and/or the size in bits of the key or the combination of
* the two is not supported.
*/
static psa_status_t get_expected_key_size( const psa_key_attributes_t *attributes,
size_t *expected_size )
static psa_status_t get_key_buffer_size(
const psa_key_attributes_t *attributes,
size_t *key_buffer_size )
{
size_t buffer_size = 0;
psa_key_location_t location = PSA_KEY_LIFETIME_GET_LOCATION( attributes->core.lifetime );
psa_key_type_t key_type = attributes->core.type;
size_t key_bits = attributes->core.bits;
*key_buffer_size = 0;
switch( location )
{
case PSA_KEY_LOCATION_LOCAL_STORAGE:
buffer_size = PSA_EXPORT_KEY_OUTPUT_SIZE( key_type, key_bits );
if( buffer_size == 0 )
return( PSA_ERROR_NOT_SUPPORTED );
*expected_size = buffer_size;
return( PSA_SUCCESS );
#if defined(PSA_CRYPTO_DRIVER_TEST)
case PSA_CRYPTO_TEST_DRIVER_LIFETIME:
#ifdef TEST_DRIVER_KEY_CONTEXT_SIZE_FUNCTION
*expected_size = test_size_function( key_type, key_bits );
*key_buffer_size = test_size_function( key_type, key_bits );
return( PSA_SUCCESS );
#else /* TEST_DRIVER_KEY_CONTEXT_SIZE_FUNCTION */
if( PSA_KEY_TYPE_IS_KEY_PAIR( key_type ) )
{
int public_key_overhead = ( ( TEST_DRIVER_KEY_CONTEXT_STORE_PUBLIC_KEY == 1 ) ?
PSA_EXPORT_KEY_OUTPUT_SIZE( key_type, key_bits ) : 0 );
*expected_size = TEST_DRIVER_KEY_CONTEXT_BASE_SIZE
int public_key_overhead =
( ( TEST_DRIVER_KEY_CONTEXT_STORE_PUBLIC_KEY == 1 ) ?
PSA_EXPORT_KEY_OUTPUT_SIZE( key_type, key_bits ) : 0 );
*key_buffer_size = TEST_DRIVER_KEY_CONTEXT_BASE_SIZE
+ TEST_DRIVER_KEY_CONTEXT_PUBLIC_KEY_SIZE
+ public_key_overhead;
}
else if( PSA_KEY_TYPE_IS_PUBLIC_KEY( attributes->core.type ) )
else if( PSA_KEY_TYPE_IS_PUBLIC_KEY( key_type ) )
{
*expected_size = TEST_DRIVER_KEY_CONTEXT_BASE_SIZE
*key_buffer_size = TEST_DRIVER_KEY_CONTEXT_BASE_SIZE
+ TEST_DRIVER_KEY_CONTEXT_PUBLIC_KEY_SIZE;
}
else if ( !PSA_KEY_TYPE_IS_KEY_PAIR( key_type ) &&
!PSA_KEY_TYPE_IS_PUBLIC_KEY ( attributes->core.type ) )
!PSA_KEY_TYPE_IS_PUBLIC_KEY ( key_type ) )
{
*expected_size = TEST_DRIVER_KEY_CONTEXT_BASE_SIZE
*key_buffer_size = TEST_DRIVER_KEY_CONTEXT_BASE_SIZE
+ TEST_DRIVER_KEY_CONTEXT_SYMMETRIC_FACTOR
* ( ( key_bits + 7 ) / 8 );
}
@ -345,10 +340,21 @@ psa_status_t psa_driver_wrapper_generate_key( const psa_key_attributes_t *attrib
* with storage. */
if( slot->key.data == NULL )
{
status = get_expected_key_size( attributes, &export_size );
if( status != PSA_SUCCESS )
return( status );
if( location == PSA_KEY_LOCATION_LOCAL_STORAGE )
{
export_size = PSA_KEY_EXPORT_MAX_SIZE( attributes->core.type,
attributes->core.bits );
if( export_size == 0 )
return( PSA_ERROR_NOT_SUPPORTED );
}
else
{
status = get_key_buffer_size( attributes, &export_size );
if( status != PSA_SUCCESS )
return( status );
}
slot->key.data = mbedtls_calloc(1, export_size);
if( slot->key.data == NULL )
return( PSA_ERROR_INSUFFICIENT_MEMORY );