Path: utzoo!utgpu!watmath!uunet!cbmvax!ditto
From: ditto@cbmvax.UUCP (Michael "Ford" Ditto)
Newsgroups: unix-pc.general
Subject: Re: Is there a back door?
Message-ID: <5774@cbmvax.UUCP>
Date: 25 Jan 89 01:46:35 GMT
References: <2384@cuuxb.ATT.COM> <102@gnosys.UUCP> <5749@cbmvax.UUCP> <151@conrad.UUCP>
Reply-To: ditto@cbmvax.UUCP (Michael "Ford" Ditto)
Organization: Commodore Technology, West Chester, PA
Lines: 18

In article <151@conrad.UUCP> sac@conrad.UUCP (Steven A. Conrad) writes:
[ about "writing" on the write-protected installation floppy ]

>I doubt it was an intention to enable
>writing on a read-only disk.  Whether this is actually exploited is
>doubtful, since buffer updating may not be predictable.

It is exploited in several ways, such as the use of command substitution
(backquotes) in the installation scripts.  Also, it appears that they
disabled write-protect error reporting on the floppy drive rather than
modify Unix to allow read-only mounting of the root device.
-- 
					-=] Ford [=-

"The number of Unix installations	(In Real Life:  Mike Ditto)
has grown to 10, with more expected."	ford@kenobi.cts.com
- The Unix Programmer's Manual,		...!sdcsvax!crash!elgar!ford
  2nd Edition, June, 1972.		ditto@cbmvax.commodore.com