Add an input check in psa_its_set
diff --git a/library/psa_its_file.c b/library/psa_its_file.c
index 05ca8af..0935b27 100644
--- a/library/psa_its_file.c
+++ b/library/psa_its_file.c
@@ -214,9 +214,12 @@
n = fwrite( &header, 1, sizeof( header ), stream );
if( n != sizeof( header ) )
goto exit;
- n = fwrite( p_data, 1, data_length, stream );
- if( n != data_length )
- goto exit;
+ if( data_length != 0 )
+ {
+ n = fwrite( p_data, 1, data_length, stream );
+ if( n != data_length )
+ goto exit;
+ }
status = PSA_SUCCESS;
exit: