Re: [PATCH] ASoC: apple: mca: Annotate struct mca_data with __counted_by

[Kees Cook]

On Fri, Sep 22, 2023 at 10:50:50AM -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 mca_data.

Friendly ping. Mark, can you pick this up please?

Thanks!

-Kees

> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: "Martin Povišer" <povik+lin@xxxxxxxxxxx>
> Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: Jaroslav Kysela <perex@xxxxxxxx>
> Cc: Takashi Iwai <tiwai@xxxxxxxx>
> Cc: asahi@xxxxxxxxxxxxxxx
> Cc: alsa-devel@xxxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
>  sound/soc/apple/mca.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/apple/mca.c b/sound/soc/apple/mca.c
> index ce77934f3eef..99e547ef95e6 100644
> --- a/sound/soc/apple/mca.c
> +++ b/sound/soc/apple/mca.c
> @@ -161,7 +161,7 @@ struct mca_data {
>  	struct mutex port_mutex;
>  
>  	int nclusters;
> -	struct mca_cluster clusters[];
> +	struct mca_cluster clusters[] __counted_by(nclusters);
>  };
>  
>  static void mca_modify(struct mca_cluster *cl, int regoffset, u32 mask, u32 val)
> -- 
> 2.34.1
> 

-- 
Kees Cook