Re: [PATCH 8/9] drm/vmwgfx: Annotate struct vmw_surface_dirty with __counted_by

[Zack Rusin]

On Fri, 2023-09-22 at 10:32 -0700, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct vmw_surface_dirty.
> 
> [1]
> https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Zack Rusin <zackr@xxxxxxxxxx>
> Cc: VMware Graphics Reviewers <linux-graphics-maintainer@xxxxxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxxx>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> index 5db403ee8261..2d1d857f99ae 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> @@ -77,7 +77,7 @@ struct vmw_surface_offset {
>  struct vmw_surface_dirty {
>         struct vmw_surface_cache cache;
>         u32 num_subres;
> -       SVGA3dBox boxes[];
> +       SVGA3dBox boxes[] __counted_by(num_subres);
>  };
>  
>  static void vmw_user_surface_free(struct vmw_resource *res);

Thanks!

Reviewed-by: Zack Rusin <zackr@xxxxxxxxxx>