Re: [PATCH 14/14] net: sched: Annotate struct tc_pedit with __counted_by

[Gustavo A. R. Silva]

On 9/22/23 11:28, 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 tc_pedit.

I think the annotation for struct tc_pedit_sel is missing.

Thanks
--
Gustavo

> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> 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
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
>   net/sched/act_pedit.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
> index 1ef8fcfa9997..77c407eff3b0 100644
> --- a/net/sched/act_pedit.c
> +++ b/net/sched/act_pedit.c
> @@ -515,11 +515,11 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
>   		spin_unlock_bh(&p->tcf_lock);
>   		return -ENOBUFS;
>   	}
> +	opt->nkeys = parms->tcfp_nkeys;
>   
>   	memcpy(opt->keys, parms->tcfp_keys,
>   	       flex_array_size(opt, keys, parms->tcfp_nkeys));
>   	opt->index = p->tcf_index;
> -	opt->nkeys = parms->tcfp_nkeys;
>   	opt->flags = parms->tcfp_flags;
>   	opt->action = p->tcf_action;
>   	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;