CVE-2024-57798

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

drm/dp_mst: Ensure mst_primary pointer is valid in drm_dp_mst_handle_up_req()

While receiving an MST up request message from one thread in drm_dp_mst_handle_up_req(), the MST topology could be removed from another thread via drm_dp_mst_topology_mgr_set_mst(false), freeing mst_primary and setting drm_dp_mst_topology_mgr::mst_primary to NULL. This could lead to a NULL deref/use-after-free of mst_primary in drm_dp_mst_handle_up_req().

Avoid the above by holding a reference for mst_primary in drm_dp_mst_handle_up_req() while it's used.

v2: Fix kfreeing the request if getting an mst_primary reference fails.

This issue is considered to be a moderate impact flaw, as the exploitation for this will need an ADMIN (or ROOT) privilege (PR:H).

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.