The vmwsurfacedefineioctl function in drivers/gpu/drm/vmwgfx/vmwgfxsurface.c in the Linux kernel through 4.10.5 does not check for a zero value of certain levels data, which allows local users to cause a denial of service (ZEROSIZEPTR dereference, and GPF and possibly panic) via a crafted ioctl call for a /dev/dri/renderD* device.