[PATCH 4.4 57/84] drm/vmwgfx: NULL pointer dereference from vmw_cmd_dx_view_define()

[Greg Kroah-Hartman]

From: Murray McAllister <murray.mcallister@xxxxxxxxx>

commit bcd6aa7b6cbfd6f985f606c6f76046d782905820 upstream.

If SVGA_3D_CMD_DX_DEFINE_RENDERTARGET_VIEW is called with a surface
ID of SVGA3D_INVALID_ID, the srf struct will remain NULL after
vmw_cmd_res_check(), leading to a null pointer dereference in
vmw_view_add().

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: d80efd5cb3de ("drm/vmwgfx: Initial DX support")
Signed-off-by: Murray McAllister <murray.mcallister@xxxxxxxxx>
Reviewed-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>


---
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -2682,6 +2682,10 @@ static int vmw_cmd_dx_view_define(struct
 	if (view_type == vmw_view_max)
 		return -EINVAL;
 	cmd = container_of(header, typeof(*cmd), header);
+	if (unlikely(cmd->sid == SVGA3D_INVALID_ID)) {
+		DRM_ERROR("Invalid surface id.\n");
+		return -EINVAL;
+	}
 	ret = vmw_cmd_res_check(dev_priv, sw_context, vmw_res_surface,
 				user_surface_converter,
 				&cmd->sid, &srf_node);