Re: [PATCH v5 net 1/6] net/sched: sch_ingress: Only create under TC_H_INGRESS

[Pedro Tammela <pctammela@mojatatu.com>]

On 23/05/2023 22:17, Peilin Ye wrote:
> From: Peilin Ye <peilin.ye@bytedance.com>
> 
> ingress Qdiscs are only supposed to be created under TC_H_INGRESS.
> Return -EOPNOTSUPP if 'parent' is not TC_H_INGRESS, similar to
> mq_init().
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-by: syzbot+b53a9c0d1ea4ad62da8b@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/r/0000000000006cf87705f79acf1a@google.com/
> Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>

Tested-by: Pedro Tammela <pctammela@mojatatu.com>

> ---
> change in v5:
>    - avoid underflowing @ingress_needed_key in ->destroy(), reported by
>      Pedro
> 
> change in v3, v4:
>    - add in-body From: tag
> 
>   net/sched/sch_ingress.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
> index 84838128b9c5..f9ef6deb2770 100644
> --- a/net/sched/sch_ingress.c
> +++ b/net/sched/sch_ingress.c
> @@ -80,6 +80,9 @@ static int ingress_init(struct Qdisc *sch, struct nlattr *opt,
>   	struct net_device *dev = qdisc_dev(sch);
>   	int err;
>   
> +	if (sch->parent != TC_H_INGRESS)
> +		return -EOPNOTSUPP;
> +
>   	net_inc_ingress_queue();
>   
>   	mini_qdisc_pair_init(&q->miniqp, sch, &dev->miniq_ingress);
> @@ -101,6 +104,9 @@ static void ingress_destroy(struct Qdisc *sch)
>   {
>   	struct ingress_sched_data *q = qdisc_priv(sch);
>   
> +	if (sch->parent != TC_H_INGRESS)
> +		return;
> +
>   	tcf_block_put_ext(q->block, sch, &q->block_info);
>   	net_dec_ingress_queue();
>   }