Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!tektronix!tekcrl!terryl
From: terryl@tekcrl.CRL.TEK.COM
Newsgroups: comp.bugs.misc
Subject: Re: Bug in Ultrix 2.0:setting the sticky bit
Keywords: tricky sticky Sun
Message-ID: <2862@tekcrl.CRL.TEK.COM>
Date: 26 Jul 88 00:08:04 GMT
References: <552@philmds.UUCP> <241@pigs.UUCP> <3341@palo-alto.DEC.COM> <472@cf-cm.UUCP> <472@draken.nada.kth.se>
Reply-To: terryl@tekcrl.CRL.TEK.COM
Organization: Tektronix, Inc., Beaverton,  OR.
Lines: 38

In article <472@draken.nada.kth.se> zap@nada.kth.se (Svante Lindahl) writes:
>[ Bug: anybody can create file with sticky-bit.
>  Leo de Wit found the bug under Ultrix 2.0.
>  Joe Bob Willie reports no bug on Plexus.
>  Paul Vixie finds bug on Ultrix 2.x, but it is not present on
>  the Ultrix 1.2 and 4.3BSD systems he tested.
>  Robert Evans says that SunOS 3.5 has it. ]
>
>I tested the following systems:
>Pyramid OSx 4.0:	 Bug present
>Sequent Dynix 3.0.4:	 Bug present
>VAX 4.3BSD:		 Bug not present
>VAX 4.3BSD+NFS (MtXinu): Bug present
>Sun SunOS 3.4.2		 Bug present
>
>All the systems were the bug has been found have NFS. None of the
>systems that don't have the bug have NFS. Draw your own conclusions
>from that.


     Perusing kernel sources, one can find (for 4.2/4.3 generic-type systems)
the following code fragment(when creating a file for the FIRST time):

			.... = ....(arg&07777&(~ISVTX));

where .... is something to keep the ATT lawyers (and Berkeley's!!! (-:) off
my back; ISVTX is the "sticky bit". So one can see that under generic 4.3
systems, no one (not even root) can create a file with the "sticky bit" set.

     Looking at kernel sources for an NFS machine, I found a similar code
fragment, but without the corresponding ISVTX (actually, I found it with the
fragment in, but the log specifically said it was a fix; earlier versions did
NOT have the corresponding ISVTX fragment).

     So, from this information, I think it is safe to assume that it is a
bug peculiar to NFS, and not 4.2/4.3 generic-type systems (which is strange,
because the NFS code is VERY close to the generic 4.2/4.3 code; sounds like
someone fat-fingered it....).