Re: [PATCH] netem: Annotate struct disttable with __counted_by

[Gustavo A. R. Silva]

On 10/4/23 01:18, 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 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 disttable.
>
> Cc: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>
> Cc: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
> Cc: Cong Wang <xiyou.wangcong@xxxxxxxxx>
> Cc: Jiri Pirko <jiri@xxxxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

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

Thanks
--
Gustavo

> ---
>   net/sched/sch_netem.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
> index 4ad39a4a3cf5..6ba2dc191ed9 100644
> --- a/net/sched/sch_netem.c
> +++ b/net/sched/sch_netem.c
> @@ -67,7 +67,7 @@
>   
>   struct disttable {
>   	u32  size;
> -	s16 table[];
> +	s16 table[] __counted_by(size);
>   };
>   
>   struct netem_sched_data {