D. Allen [CGL]" <idallen@watcgl.waterloo.edu> (03/08/91)
ULTRIX V4.1 (Rev. 52) DS5400
Start up a "script" session. Run this shell script in the background
from inside script:
#!/bin/sh
trap '' 0 1 2 15 17 21 22
while :; do
echo $0 writes on your tty and you can't prevent it
sleep 2
done
Exit from script and immediately rlogin to your machine (e.g. rlogin
localhost) as any user. If you get the same pty as script was using,
you'll discover the shell script you left running writing all over it.
If you didn't get the same pty, some other poor rlogin user got it and
you'd better kill your script before you really annoy them.
Ultrix doesn't give you any way of knowing, when you rlogin, that you
have a private tty. Anyone could have a process waiting to ambush you.
I'd be interested in knowing if Ultrix sites running in one of the
enhanced security modes also have this feature.
Better versions of rlogind vhangup() the tty before giving it to you, so
processes that you didn't start this session can't write (or read) it.
#include <standard wish for DEC electronic SPR>
--
-IAN! (Ian! D. Allen) idallen@watcgl.uwaterloo.ca idallen@watcgl.waterloo.edu
[129.97.128.64] Computer Graphics Lab/University of Waterloo/Ontario/Canada