linux-kernel - Re: [Stable-review] [141/145] KVM: x86 emulator: Check CPL level during privilege instruction emulation

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Date:	Sun, 14 Mar 2010 19:22:03 +0100
From:	Stefan Bader <stefan.bader@...onical.com>
To:	Greg KH <gregkh@...e.de>
CC:	Ben Hutchings <ben@...adent.org.uk>,
	Gleb Natapov <gleb@...hat.com>, linux-kernel@...r.kernel.org,
	stable-review@...nel.org, Avi Kivity <avi@...hat.com>,
	akpm@...ux-foundation.org, torvalds@...ux-foundation.org,
	stable@...nel.org, alan@...rguk.ukuu.org.uk
Subject: Re: [Stable-review] [141/145] KVM: x86 emulator: Check CPL	level
 during privilege instruction emulation

Greg KH wrote:
> On Sat, Mar 13, 2010 at 08:37:57PM +0000, Ben Hutchings wrote:
>> On Fri, 2010-03-12 at 16:27 -0800, Greg KH wrote:
>>> 2.6.32-stable review patch.  If anyone has any objections, please let me know.
>>>
>>> ----------------
>>> From: Gleb Natapov <gleb@...hat.com>
>>>
>>> commit e92805ac1228626c59c865f2f4e9059b9fb8c97b upstream.
>>>
>>> Add CPL checking in case emulator is tricked into emulating
>>> privilege instruction from userspace.
>> There were more security fixes released along with this, which surely
>> belong in a stable update:
>>
>> 1871c6020d7308afb99127bba51f04548e7ca84e KVM: x86 emulator: fix memory access during x86 emulation

This one caused a regression for AMD cpus. There is a patch for it in the
process but not upstream, yet.

>> f850e2e603bf5a05b0aee7901857cf85715aa694 KVM: x86 emulator: Check IOPL level during io instruction emulation
>> d4c6a1549c056f1d817e8f6f2f97d8b44933472f KVM: x86 emulator: Fix popf emulation
> 
> Yes, there were a number of kvm patches that I could not apply either
> because they did not apply, or because they caused build errors.  These
> are some of them.  I have asked the KVM developers to properly backport
> them as I know nothing about KVM.  Hopefully that will be done for the
> next round of stable releases.

I have done some backport work for 2.6.32 at least. This can be found at

git://kernel.ubuntu.com/smb/linux-2.6.32.y kvm

I have successfully booted a guest after the changes but it would surely help if
the KVM developers could give some review on the set.

Stefan
> thanks,
> 
> greg k-h
> 
> _______________________________________________
> Stable-review mailing list
> Stable-review@...ux.kernel.org
> http://linux.kernel.org/mailman/listinfo/stable-review

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