ACK: [SRU Bionic 0/1] CVE-2021-38198

[Tim Gardner]

Acked-by: Tim Gardner <tim.gardner at canonical.com>

Good test results from a reproducer.

On 9/22/21 12:47 PM, Thadeu Lima de Souza Cascardo wrote:
> [Impact]
>   It was discovered that the KVM hypervisor implementation in the Linux
>   kernel did not properly compute the access permissions for shadow pages in
>   some situations. A local attacker could use this to cause a denial of
>   service.
> 
> [Backport]
> I picked up the backport that was done for 4.19.y, as there was a small
> conflict in one of the hunks and a file rename.
> 
> [Test case]
> kvm-unit-tests access test will check for this bug. It fails before the
> fix and passes after the fix.
> 
> [Potential regression]
> KVM guest page faults could be erronously handled, causing issues on
> KVM guests.
> 
> Lai Jiangshan (1):
>    KVM: X86: MMU: Use the correct inherited permissions to get shadow
>      page
> 
>   Documentation/virtual/kvm/mmu.txt |  4 ++--
>   arch/x86/kvm/paging_tmpl.h        | 14 +++++++++-----
>   2 files changed, 11 insertions(+), 7 deletions(-)
> 

-- 
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Tim Gardner
Canonical, Inc