4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vladis Dronov <vdronov@xxxxxxxxxx> commit ee9c4e681ec4f58e42a83cb0c22a0289ade1aacf upstream. The 'req->mip_levels' parameter in vmw_gb_surface_define_ioctl() is a user-controlled 'uint32_t' value which is used as a loop count limit. This can lead to a kernel lockup and DoS. Add check for 'req->mip_levels'. References: https://bugzilla.redhat.com/show_bug.cgi?id=1437431 Signed-off-by: Vladis Dronov <vdronov@xxxxxxxxxx> Reviewed-by: Sinclair Yeh <syeh@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c @@ -1293,6 +1293,9 @@ int vmw_gb_surface_define_ioctl(struct d if (req->multisample_count != 0) return -EINVAL; + if (req->mip_levels > DRM_VMW_MAX_MIP_LEVELS) + return -EINVAL; + if (unlikely(vmw_user_surface_size == 0)) vmw_user_surface_size = ttm_round_pot(sizeof(*user_srf)) + 128;