psa: Add magic header to storage backend
Add a magic header to the storage format used with files. The
header is used as an initial check that the data is what we expect,
rather than garbage data.
}
#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 type[sizeof( psa_key_type_t )];
uint8_t policy[sizeof( psa_key_policy_t )];
@@ -82,6 +89,7 @@ void psa_format_key_data_for_storage( const uint8_t *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(type, storage_format->type, 0);
PUT_UINT32_LE(policy->usage, storage_format->policy, 0);
@@ -90,6 +98,14 @@ void psa_format_key_data_for_storage( const uint8_t *data,
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,
@@ -97,10 +113,18 @@ psa_status_t psa_parse_key_data_from_storage( const uint8_t *storage_data,
psa_key_type_t *type,
psa_key_policy_t *policy )
{
+ psa_status_t status;
const psa_persistent_key_storage_format *storage_format =
(const psa_persistent_key_storage_format *)storage_data;
uint32_t version;
+ 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 );
