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From: Jakub Kicinski <kuba@kernel.org>
To: tcs.kernel@gmail.com, vinicius.gomes@intel.com
Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
	davem@davemloft.net, netdev@vger.kernel.org,
	Haimin Zhang <tcs_kernel@tencent.com>
Subject: Re: [PATCH] net:sched fix array-index-out-of-bounds in taprio_change
Date: Thu, 12 Aug 2021 10:53:21 -0700	[thread overview]
Message-ID: <20210812105321.0de11e3e@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <1628658609-1208-1-git-send-email-tcs_kernel@tencent.com>

On Wed, 11 Aug 2021 13:10:09 +0800 tcs.kernel@gmail.com wrote:
> From: Haimin Zhang <tcs_kernel@tencent.com>
> 
> syzbot report an array-index-out-of-bounds in taprio_change
> index 16 is out of range for type '__u16 [16]'
> that's because mqprio->num_tc is lager than TC_MAX_QUEUE,so we check
> the return value of netdev_set_num_tc.
> 
> Reported-by: syzbot+2b3e5fb6c7ef285a94f6@syzkaller.appspotmail.com
> Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com>
> ---
>  net/sched/sch_taprio.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
> index 9c79374..1ab2fc9 100644
> --- a/net/sched/sch_taprio.c
> +++ b/net/sched/sch_taprio.c
> @@ -1513,7 +1513,9 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
>  	taprio_set_picos_per_byte(dev, q);
>  
>  	if (mqprio) {
> -		netdev_set_num_tc(dev, mqprio->num_tc);
> +		err = netdev_set_num_tc(dev, mqprio->num_tc);
> +		if (err)
> +			goto free_sched;

taprio_set_picos_per_byte() already got called and applied some of the
changes. It seems like the early return from taprio_parse_mqprio_opt()
if dev->num_tc is non-zero is incorrect. That function is supposed to
validate that mqprio_opt() is correct AFAIU. That would mean:

Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule")

Vinicius - WDYT?

>  		for (i = 0; i < mqprio->num_tc; i++)
>  			netdev_set_tc_queue(dev, i,
>  					    mqprio->count[i],


  parent reply	other threads:[~2021-08-12 17:53 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11  5:10 tcs.kernel
2021-08-11  7:44 ` Eric Dumazet
2021-08-11  8:30   ` Pavel Skripkin
2021-08-11  8:35     ` Pavel Skripkin
2021-08-11  8:36   ` Haimin Zhang
2021-08-30  2:09     ` Haimin Zhang
2021-08-30 16:10       ` Jakub Kicinski
2021-08-12 17:53 ` Jakub Kicinski [this message]
  -- strict thread matches above, loose matches on Subject: below --
2021-08-11  4:09 tcs.kernel

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