Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!vsi!friedl
From: friedl@vsi.COM (Stephen J. Friedl)
Newsgroups: comp.bugs.sys5
Subject: Re: ulimit
Summary: Kids, don't do this at work either
Message-ID: <1101@vsi.COM>
Date: 23 Apr 89 04:10:31 GMT
References: <19516@genrad.UUCP> <1319@nusdhub.UUCP> <10075@smoke.BRL.MIL> <100455@sun.Eng.Sun.COM>
Organization: V-Systems, Inc. -- Santa Ana, CA
Lines: 31

In article <100455@sun.Eng.Sun.COM>, plocher%sally@Sun.COM (John Plocher) writes:
< In all this talk about ULIMIT don't forget that there is at least
< one known bug in the AT&T SVr[23] implementation:
< 
< 	% su
< 	password: xxxxxxx
< 	# cp /etc/passwd /etc/passwd.old ; exit
< 	% ulimit 0 ; passwd
<	(type old/new/again password)
< 	% ls -l /etc/passwd*
< 	-rw-r--r--  1 root            0 Apr  3 10:44 /etc/passwd
< 	-rw-r--r--  1 root          439 Apr  3 10:40 /etc/passwd.old

OK so far, we've just trashed the live copy of the password file.

< 	% su
< 	password: xxxxxxx
< 	# cp /etc/passwd.old /etc/passwd

Oops.  su will likely fail here ("su: Unknown id: root") and you may
be stuck in a big way (can't become root, can't restore the file, can't
go to single user mode, etc.).  If you try this, have a root terminal
session on a nearby terminal *before* you start.

     Steve

-- 
Stephen J. Friedl / V-Systems, Inc. / Santa Ana, CA / +1 714 545 6442 
3B2-kind-of-guy   / friedl@vsi.com  / {attmail, uunet, etc}!vsi!friedl

"I'm making a fashion statement: I'm saying I don't know how to dress." - me