ACK/Cmnt: [UBUNTU OEM-5.7 0/1] CVE-2022-2590

[Thadeu Lima de Souza Cascardo]

On Tue, Apr 04, 2023 at 08:50:42AM -0600, Tim Gardner wrote:
> On 4/4/23 7:55 AM, Thadeu Lima de Souza Cascardo wrote:
> > [Impact]
> > Attackers can write to shmem files (on tmpfs, for example) without having write permissions.
> > 
> > [Fix]
> > The upstream fix is not appropriate to 5.17 and the suggestion was to revert the offending commit.
> > 
> > [Test case]
> > PoC was tested and stopped working with the revert applied.
> > 
> > Thadeu Lima de Souza Cascardo (1):
> >    UBUNTU: SAUCE: Revert "mm/shmem: unconditionally set pte dirty in
> >      mfill_atomic_install_pte"
> > 
> >   mm/shmem.c       | 1 +
> >   mm/userfaultfd.c | 3 ++-
> >   2 files changed, 3 insertions(+), 1 deletion(-)
> > 
> Acked-by: Tim Gardner <tim.gardner at canonical.com>
> 
> Is this really a SAUCE patch ?
> -- 
> -----------
> Tim Gardner
> Canonical, Inc
> 

It is because it has not been reverted upstream, but fixed properly. The proper
fix was just not easily backported to 5.17.

Cascardo.