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Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!mgnetp!ltuxa!ttrdc!levy
From: levy@ttrdc.UUCP (Daniel R. Levy)
Newsgroups: net.unix
Subject: Re: Automatic root login
Message-ID: <613@ttrdc.UUCP>
Date: Mon, 2-Dec-85 21:28:37 EST
Article-I.D.: ttrdc.613
Posted: Mon Dec  2 21:28:37 1985
Date-Received: Thu, 5-Dec-85 04:21:33 EST
References: <306@spock.UUCP> <4513@mordor.UUCP> <476@graffiti.UUCP>
Organization: AT&T, Computer Systems Division, Skokie, IL
Lines: 25

In article <476@graffiti.UUCP>, peter@graffiti.UUCP (Peter da Silva) writes:
>When you run a setuid program while you are setuid-ed
>to someone else, it thinks you have your original uid, not whomever you have
>setuid to. To demostrate this, try to perform an rmdir on someone's empty
>directory while you are setuid to them. This is either a bug or a feature
>depending on your perspective.
>--
>Name: Peter da Silva

I noticed something else funny (peculiar etc.) with respect to this.  If I
am root and run cu to another system and attempt to do a ~%take from the
remote, I am DENIED PERMISSION to divert except to a publicly writeable
directory like /tmp !!!  (cu is setuid uucp)  This is when I log in on the
console as root.  (This points out a bug in cu anyway; it also would be nicer
if upon getting the builtin ~%take sequence, cu would first check whether
it is indeed possible to write or create the desired file before telling the
remote to send it.  I have added this feature to a cu I have running here
but that's beside the point anyhow; the point is setuid.)
-- 
 -------------------------------    Disclaimer:  The views contained herein are
|       dan levy | yvel nad      |  my own and are not at all those of my em-
|         an engihacker @        |  ployer or the administrator of any computer
| at&t computer systems division |  upon which I may hack.
|        skokie, illinois        |
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