[PATCH] UBUNTU: SAUCE: [x86] implement cs-limit nx-emulation for ia32

[Kees Cook]

Hi Tim,

On Mon, May 04, 2009 at 02:31:10PM -0600, Tim Gardner wrote:
> OK - here goes:
> 
> https://bugs.edge.launchpad.net/ubuntu/karmic/+source/linux/+bug/369978/comments/3

Thanks!  I will be running it on my NX-less laptop as soon as the kernel is
uploaded.  :)

BTW, on IRC you'd asked for an example of how this protection could
be seen.  The first thing that came to mind was the current Adobe Reader
vulnerability[1].  This software is in our partner repository, and is not
built with our toolchain, leaving it without stack canary protections.
Execution of arbitrary code from the exploits in the wild[2] would be
stopped by NX (and this patch provides NX via CS-limits on hardware that
lacks true NX).

-Kees

[1] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-1492
[2] http://www.milw0rm.com/exploits/8569
    http://securitylabs.websense.com/content/Blogs/3202.aspx

-- 
Kees Cook
Ubuntu Security Team