Re: [PATCH] aio: Annotate struct kioctx_table with __counted_by

[Gustavo A. R. Silva]

On 9/15/23 14:14, 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 kioctx_table.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Benjamin LaHaise <bcrl@xxxxxxxxx>
> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Christian Brauner <brauner@xxxxxxxxxx>
> Cc: linux-aio@xxxxxxxxx
> Cc: linux-fsdevel@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

Thanks
--
Gustavo

> ---
>   fs/aio.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/aio.c b/fs/aio.c
> index a4c2a6bac72c..f8589caef9c1 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -80,7 +80,7 @@ struct aio_ring {
>   struct kioctx_table {
>   	struct rcu_head		rcu;
>   	unsigned		nr;
> -	struct kioctx __rcu	*table[];
> +	struct kioctx __rcu	*table[] __counted_by(nr);
>   };
>   
>   struct kioctx_cpu {