[32669] in bugtraq
Re: GNU screen buffer overflow
daemon@ATHENA.MIT.EDU (Casper Dik)
Wed Dec 3 17:16:44 2003
Message-Id: <200312032117.hB3LHeI00311@sunnl.Holland.Sun.COM>
To: Pavel Kankovsky <peak@argo.troja.mff.cuni.cz>
Cc: Kyle Sallee <cromwell@metalab.unc.edu>, bugtraq@securityfocus.com
In-Reply-To: <20031203202946.727B.0@argo.troja.mff.cuni.cz>
Date: Wed, 03 Dec 2003 22:17:40 +0100
From: Casper Dik <casper@holland.sun.com>
>On Mon, 1 Dec 2003, Kyle Sallee wrote:
>
>> > With devpts and libutempter it is possible to install fully functional
>> > screen without suid/sgid.
>>
>> Does that mean any program that links with libutempter gains
>> complete suid/sgid root functionality, or only when executing
>> the functions in the libutempter library, please?
>
>This means you do not need setuid root because devpts sets up the slave
>pty owner and group automatically and you do not need direct access to
>utmp/wtmp, e.g. via setgid utmp, because libtempter functions call an
>external setgid utmp helper called utempter to modify those files (the
>calling process is required to hold a corresponding master pty).
Nearly exactly like in generic SVR4 where ptys are setup using
/usr/lib/pt_chmod; and in Solaris there's the additional "utmp_update"
programs which allows you to set utmp entries; this is all hidden behind the
libc routines.
Casper
