netdev - Re: [PATCH v2] net/sched: fix use-after-free in taprio_dev

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aEs3Sotbf81FShq3@pop-os.localdomain>
Date: Thu, 12 Jun 2025 13:23:38 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: Hyunwoo Kim <imv4bel@...il.com>
Cc: vinicius.gomes@...el.com, jhs@...atatu.com, jiri@...nulli.us,
	davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
	pabeni@...hat.com, horms@...nel.org, vladimir.oltean@....com,
	netdev@...r.kernel.org, v4bel@...ori.io
Subject: Re: [PATCH v2] net/sched: fix use-after-free in taprio_dev_notifier

On Thu, Jun 12, 2025 at 07:16:55AM -0400, Hyunwoo Kim wrote:
> diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
> index 14021b812329..bd2b02d1dc63 100644
> --- a/net/sched/sch_taprio.c
> +++ b/net/sched/sch_taprio.c
> @@ -1320,6 +1320,7 @@ static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,
>  	if (event != NETDEV_UP && event != NETDEV_CHANGE)
>  		return NOTIFY_DONE;
>  
> +	rcu_read_lock();
>  	list_for_each_entry(q, &taprio_list, taprio_list) {
>  		if (dev != qdisc_dev(q->root))
>  			continue;
> @@ -1328,16 +1329,17 @@ static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,

There is a taprio_set_picos_per_byte() call here, it calls
__ethtool_get_link_ksettings() which could be blocking.

For instance, gve_get_link_ksettings() calls
gve_adminq_report_link_speed() which is a blocking function.

So I am afraid we can't enforce an atomic context here.

Sorry.
Cong