CVE-2023-52856

/// Technical description

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

drm/bridge: lt8912b: Fix crash on bridge detach

The lt8912b driver, in its bridge detach function, calls

drm_connector_unregister() and drm_connector_cleanup().

drm_connector_unregister() should be called only for connectors

explicitly registered with drm_connector_register(), which is not the

case in lt8912b.

The driver's drm_connector_funcs.destroy hook is set to

drm_connector_cleanup().

Thus the driver should not call either drm_connector_unregister() nor

drm_connector_cleanup() in its lt8912_bridge_detach(), as they cause a

crash on bridge detach:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000

Mem abort info:

ESR = 0x0000000096000006

EC = 0x25: DABT (current EL), IL = 32 bits

SET = 0, FnV = 0

EA = 0, S1PTW = 0

FSC = 0x06: level 2 translation fault

Data abort info:

ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000

CM = 0, WnR = 0, TnD = 0, TagAccess = 0

GCS = 0,

/// 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