psa: driver wrapper: Clarify the scope of and rename get_expected_key_size
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>
diff --git a/library/psa_crypto_driver_wrappers.c b/library/psa_crypto_driver_wrappers.c
index 9440195..07888f1 100644
--- a/library/psa_crypto_driver_wrappers.c
+++ b/library/psa_crypto_driver_wrappers.c
@@ -239,61 +239,56 @@
}
#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 @@
* 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 );