CVE-2024-57876

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> drm/dp_mst: Fix resetting msg rx state after topology removal<br /> <br /> If the MST topology is removed during the reception of an MST down reply<br /> or MST up request sideband message, the<br /> drm_dp_mst_topology_mgr::up_req_recv/down_rep_recv states could be reset<br /> from one thread via drm_dp_mst_topology_mgr_set_mst(false), racing with<br /> the reading/parsing of the message from another thread via<br /> drm_dp_mst_handle_down_rep() or drm_dp_mst_handle_up_req(). The race is<br /> possible since the reader/parser doesn&amp;#39;t hold any lock while accessing<br /> the reception state. This in turn can lead to a memory corruption in the<br /> reader/parser as described by commit bd2fccac61b4 ("drm/dp_mst: Fix MST<br /> sideband message body length check").<br /> <br /> Fix the above by resetting the message reception state if needed before<br /> reading/parsing a message. Another solution would be to hold the<br /> drm_dp_mst_topology_mgr::lock for the whole duration of the message<br /> reception/parsing in drm_dp_mst_handle_down_rep() and<br /> drm_dp_mst_handle_up_req(), however this would require a bigger change.<br /> Since the fix is also needed for stable, opting for the simpler solution<br /> in this patch.