Bugtraq mailing list archives
Re: WARNING: Linux Intel Pentium Bug
From: hudson () MBAY NET (Stefan Hudson)
Date: Fri, 7 Nov 1997 09:29:26 -0800
On Fri, Nov 07, 1997 at 03:10:29AM +0000, ZombieMan wrote:
In article <3462ADCD.135B () noname com>, <noname () noname com> wrote:Check this out. If you execute F0 0F C7 C8 on a P5 it will lock the machine up. This is true for any operating system including usermode Linux. It's pretty cool. Basically, the opcodes are an invalid form of cmpxchg8b eax with a lock prefix. Has anyone seen this before? The problem doesn't show itself for the Pentium Pro or Pentium 2.Cool. It also works (sic) from V86 mode, so if you want to play around, just use DOS debug under whatever DOS emulator the OS you are using provides. Anyone try it on a Pentium MMX?
Oh dear. This is very not good. Without knowing machine level programing as well as I should, is it possible to create a patch for the, in the Linux kernel for example? Will there be a significant performance hit? This code does NOT affect Cyrix 6x86 (166+ specifically, but probably all of them) processors. If you run a multiuser, untrusted system, I suggest reserving some at your local computer supplier... unless there is an easy fix for this, there is going to be a run on them. I don't know if AMD's Pentium-clone chips are vulnerable. [Someone Else]
This bug looks far worse that FPIV. Intel will probably be forced to undergo an expensive recall, although I wonder just how Intel plans on getting the broken Pentium on my IBM thinkpad fixed. I like to let co-workers access my machine when it is hooked up to the network at work, and will have to now severely restrict any such access.
Well, it really only affects multiuser systems, where untrusted code can be executed. There are so many ways to lock Windows 95 up already, one more cause won't make that much of a difference, and that's the vast majority of Pentium users. But multiuser systems are in deep sh*t. Does anyone know if the process accounting in Linux will log the execution of this before it locks up the machine? I seem to remember that it logs on process completion, unfortunately. And is there an NT exploit for this? -- /// Stefan Hudson <hudson () mbay net> __ /// Senior Network Administrator - Monterey Bay Internet \\\/// http://www.mbay.net/ - Email: info () mbay net \XX/ Voice: 408-642-6100 Fax: 408-642-6101 Modem: 408-642-6102
Current thread:
- WARNING: Linux Intel Pentium Bug ZombieMan (Nov 06)
- Re: WARNING: Linux Intel Pentium Bug Stefan Hudson (Nov 07)
- Re: WARNING: Linux Intel Pentium Bug whiz (Nov 07)
- Re: Intel Pentium Bug George Imburgia (Nov 07)
- Re: Intel Pentium Bug Kragen \ (Nov 07)
- Re: Intel Pentium Bug Chris Pascoe (Nov 07)
- Re: Intel Pentium Bug Stefan Hudson (Nov 07)
- Re: Intel Pentium Bug Aleph One (Nov 07)
- Re: Intel Pentium Bug Eric Allman (Nov 07)
- Re: Intel Pentium Bug Dean Gaudet (Nov 07)
- Re: Intel Pentium Bug Dean Gaudet (Nov 07)
- Re: Intel Pentium Bug Colin Jenkins (Nov 07)
- Re: WARNING: Linux Intel Pentium Bug Stefan Hudson (Nov 07)