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

23 Sep 2023


      On 9/22/23 11:50, 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.
[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_...
Cc: "Martin Povišer" povik+lin@cutebit.org
Cc: Liam Girdwood lgirdwood@gmail.com
Cc: Mark Brown broonie@kernel.org
Cc: Jaroslav Kysela perex@perex.cz
Cc: Takashi Iwai tiwai@suse.com
Cc: asahi@lists.linux.dev
Cc: alsa-devel@alsa-project.org
Signed-off-by: Kees Cook keescook@chromium.org
Reviewed-by: Gustavo A. R. Silva gustavoars@kernel.org
Thanks
-- 
Gustavo

> ---
>   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)