Re: [Xen-devel] [PATCH 0/4] XSA-52..54 follow-up

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 04.06.13 at 12:00, Keir Fraser <keir.xen@xxxxxxxxx> wrote:
> On 04/06/2013 08:58, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
> 
>> The first patch really isn't as much of a follow-up than what triggered
>> the security issues to be noticed in the first place.
>> 
>> 1: x86: preserve FPU selectors for 32-bit guest code
>> 2: x86: fix XCR0 handling
>> 3: x86/xsave: adjust state management
>> 4: x86/fxsave: bring in line with recent xsave adjustments
>> 
>> The first two I would see as candidates for 4.3 (as well as
>> subsequent backporting, albeit I realize that especially the first
>> one is non-trivial), while the third is code improvement only,
>> and the fourth is really just cleanup, and hence I'd be fine with
>> deferring them until after 4.3.
>> 
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> I like the patches, 1 & 2 are good bug fixes.
> Acked-by: Keir Fraser <keir@xxxxxxx>
> 
> Patch #1 is quite scary though! I wonder really whether these long-lived
> issues must be fixed right now, let alone backported?

You can also view this as "finally we get these long standing
issues fixed" - I was aware of the selector corruption since back
when dealing with the original FXSAVE information leak, just that
no-one had an issue with this in practice.

Ben, who originally initiated this work, might want to give an
estimation on how important these fixes are for their practical
purposes. With that, I'll then defer to George for whether to
pull them in right now or only once branched.

Jan


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