Re: [PATCH] intel_txt: add s3 userspace memory integrity verification

[H. Peter Anvin]

On 12/04/2009 09:13 AM, Andi Kleen wrote:
>>>
>>> So no, you did not audit do_suspend_lowlevel to make sure it does not
>>> follow function pointers. Bad.
>>
>> We aren't aware of any code or data used by the resume path that is outside of the tboot-MAC'ed regions above--if you can point out any then we will gladly address them.
> 
> Code coverage is not enough, you need data coverage too.  If someone 
> modifies kernel data it's typically easy to subvert code as a next step.
> 

The only function pointers that are invoked on the do_suspend_lowlevel
path are some paravirt_crap pointers, but those are located inside
kernel static data.

This is not to say that this isn't a new constraint, and should be
documented, and checked ahead of time...

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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