CVE-2023-52648

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

drm/vmwgfx: Unmap the surface before resetting it on a plane state

Switch to a new plane state requires unreferencing of all held surfaces.

In the work required for mob cursors the mapped surfaces started being

cached but the variable indicating whether the surface is currently

mapped was not being reset. This leads to crashes as the duplicated

state, incorrectly, indicates the that surface is mapped even when

no surface is present. That's because after unreferencing the surface

it's perfectly possible for the plane to be backed by a bo instead of a

surface.

Reset the surface mapped flag when unreferencing the plane state surface

to fix null derefs in cleanup. Fixes crashes in KDE KWin 6.0 on Wayland:

Oops: 0000 [#1] PREEMPT SMP PTI

CPU: 4 PID: 2533 Comm: kwin_wayland Not tainted 6.7.0-rc3-vmwgfx #2

Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020

RIP: 0010:

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References