Date: Thu, 26 Feb 1998 23:27:46 -0800 From: Cy Schubert - ITSD Open Systems Group <cschuber@uumail.gov.bc.ca> To: David Dawes <dawes@rf900.physics.usyd.edu.au> Cc: Mike Smith <mike@smith.net.au>, Cy Schubert - ITSD Open Systems Group <cschuber@uumail.gov.bc.ca>, tqbf@secnet.com, freebsd-security@FreeBSD.ORG, security-officer@FreeBSD.ORG Subject: Re: OpenBSD Security Advisory: mmap() Problem Message-ID: <199802270728.XAA01171@cwsys.cwsent.com> In-Reply-To: Your message of "Fri, 27 Feb 1998 16:57:29 %2B1100." <19980227165729.27270@rf900.physics.usyd.edu.au>
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> On Thu, Feb 26, 1998 at 09:43:49PM -0800, Mike Smith wrote:
> >> I've ported this patch to FreeBSD 2.2.5R. XIG's Accelerated X server
> >> crashes trying to access the VT. To get the XIG Accelerated X server
> >> to work I've modified the patch to allow superuser to access to
> >> character devices. I'm not sure what other applications could break
> >> because of the originally posted patch or my modified patch, so
> >> additional study needs to be done.
> >
> >This modification effectively defeats much of the actual usefulness of
> >the patch. The bug is a second-order security risk in that an attacker
> >must already have obtained at least group kmem before she can take
> >advantage of it. I don't (at this point) think that we want to go
> >ahead with this until we hear from XIG.
>
> Does anyone know if it crashes an XFree86 server. XFree86 has a new
> release about to come out, and if there might be a problem here it
> would be good for us to know about it now.
It doesn't. XF86 doesn't open /dev/mem read-only, then write to it like
the XIG X server does.
>
> David
Regards, Phone: (250)387-8437
Cy Schubert Fax: (250)387-5766
UNIX Support OV/VM: BCSC02(CSCHUBER)
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