(krb5_ret_data): check for length == 0

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@2237 ec53bebd-3082-4978-b11e-865c3cabbd6b

lib/krb5/store.c

@@ -137,10 +137,13 @@ krb5_ret_data(krb5_storage *sp,
     if(ret)
 	return ret;
     data->length = size;
+    if (size) {
 	data->data = malloc(size);
 	ret = sp->fetch(sp, data->data, size);
 	if(ret != size)
 	    return (ret < 0)? errno : KRB5_CC_END;
+    } else
+	data->data = NULL;
     return 0;
 }