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Path: utzoo!linus!decvax!mulga!munnari!basser!elecvax!stephenf
From: stephenf@elecvax.OZ (Stephen Frede)
Newsgroups: net.bugs,net.bugs.4bsd
Subject: Re: stty bug + effects
Message-ID: <313@elecvax.OZ>
Date: Fri, 31-Aug-84 16:21:07 EDT
Article-I.D.: elecvax.313
Posted: Fri Aug 31 16:21:07 1984
Date-Received: Thu, 13-Sep-84 03:36:46 EDT
References: <571@bnl.UUCP> <1016@inuxc.UUCP>
Organization: EE and CS, Uni of NSW, Sydney, Australia
Lines: 17

Re: writeable terminals by all allowing anyone to stuff you up.

This is so obvious that I thought everyone must have fixed it. Of course
you can't allow your terminal to be writable by all except in the most
trusting of environments. A simple solution is to have all terminals
group owned by a controlled pseudo user (eg "daemon" on our system, or "bin"
if you like), and make the "write" command set-gid to that user. The real
owner of the terminal can then turn on or off the group write permits as
they like (via "mesg" or directly) and no-one can do funny things to your
terminal, except by using "write", and even this, only when people allow
it. Then the "write" program can be made to filter out control characters,
which these days with supersmart terminals are just as painful as going
into raw mode.

						Stephen Frede

					...decvax!mulga!stephenf:elecvax