CVE-2024-56616

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> drm/dp_mst: Fix MST sideband message body length check<br /> <br /> Fix the MST sideband message body length check, which must be at least 1<br /> byte accounting for the message body CRC (aka message data CRC) at the<br /> end of the message.<br /> <br /> This fixes a case where an MST branch device returns a header with a<br /> correct header CRC (indicating a correctly received body length), with<br /> the body length being incorrectly set to 0. This will later lead to a<br /> memory corruption in drm_dp_sideband_append_payload() and the following<br /> errors in dmesg:<br /> <br /> UBSAN: array-index-out-of-bounds in drivers/gpu/drm/display/drm_dp_mst_topology.c:786:25<br /> index -1 is out of range for type &amp;#39;u8 [48]&amp;#39;<br /> Call Trace:<br /> drm_dp_sideband_append_payload+0x33d/0x350 [drm_display_helper]<br /> drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper]<br /> drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper]<br /> <br /> memcpy: detected field-spanning write (size 18446744073709551615) of single field "&amp;msg-&gt;msg[msg-&gt;curlen]" at drivers/gpu/drm/display/drm_dp_mst_topology.c:791 (size 256)<br /> Call Trace:<br /> drm_dp_sideband_append_payload+0x324/0x350 [drm_display_helper]<br /> drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper]<br /> drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper]