diff -up expect5.45.4/exp_log.c.orig expect5.45.4/exp_log.c
--- expect5.45.4/exp_log.c.orig	2018-02-02 20:15:52.000000000 +0100
+++ expect5.45.4/exp_log.c	2018-06-27 10:46:53.065655463 +0200
@@ -499,7 +499,7 @@ expLogChannelOpen(interp,filename,append
 	Tcl_DStringAppend(&tsdPtr->logFilename,filename,-1);
     }
 
-    tsdPtr->logChannel = Tcl_OpenFileChannel(interp,newfilename,mode,0777);
+    tsdPtr->logChannel = Tcl_OpenFileChannel(interp,newfilename,mode,0666);
     if (!tsdPtr->logChannel) {
 	Tcl_DStringFree(&tsdPtr->logFilename);
 	return TCL_ERROR;