drm: vmwgfx_surface.c: copy user-array safely

Currently, there is no overflow-check with memdup_user().

Use the new function memdup_array_user() instead of memdup_user() for
duplicating the user-space array safely.

Suggested-by: David Airlie <[email protected]>
Signed-off-by: Philipp Stanner <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Zack Rusin <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: Philipp Stanner

drivers/gpu/drm/vmwgfx/vmwgfx_surface.c

@@ -777,9 +777,9 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
 	       sizeof(metadata->mip_levels));
 	metadata->num_sizes = num_sizes;
 	metadata->sizes =
-		memdup_user((struct drm_vmw_size __user *)(unsigned long)
+		memdup_array_user((struct drm_vmw_size __user *)(unsigned long)
 			    req->size_addr,
-			    sizeof(*metadata->sizes) * metadata->num_sizes);
+			    metadata->num_sizes, sizeof(*metadata->sizes));
 	if (IS_ERR(metadata->sizes)) {
 		ret = PTR_ERR(metadata->sizes);
 		goto out_no_sizes;