2021-08-30 03:49:12

by Haimin Zhang

Subject: [PATCH V2] fix array-index-out-of-bounds in taprio_change

From: Haimin Zhang <[email protected]>

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: [email protected]
Signed-off-by: Haimin Zhang <[email protected]>
---
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;
for (i = 0; i < mqprio->num_tc; i++)
netdev_set_tc_queue(dev, i,
mqprio->count[i],
--
1.8.3.1

2021-08-30 11:31:06

by patchwork-bot+netdevbpf

Subject: Re: [PATCH V2] fix array-index-out-of-bounds in taprio_change

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Mon, 30 Aug 2021 11:47:01 +0800 you wrote:
> From: Haimin Zhang <[email protected]>
>
> 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.
>
> [...]

Here is the summary with links:
- [V2] fix array-index-out-of-bounds in taprio_change
https://git.kernel.org/netdev/net-next/c/efe487fce306

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

2021-08-30 17:19:41

by Jakub Kicinski

Subject: Re: [PATCH V2] fix array-index-out-of-bounds in taprio_change

On Mon, 30 Aug 2021 11:30:06 +0000 [email protected]
wrote:
> Hello:
>
> This patch was applied to netdev/net-next.git (refs/heads/master):
>
> On Mon, 30 Aug 2021 11:47:01 +0800 you wrote:
> > From: Haimin Zhang <[email protected]>
> >
> > 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.
> >
> > [...]
>
> Here is the summary with links:
> - [V2] fix array-index-out-of-bounds in taprio_change
> https://git.kernel.org/netdev/net-next/c/efe487fce306
>
> You are awesome, thank you!

https://lore.kernel.org/netdev/20210830091046.610ceb1b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/

Oh, well...

2021-08-31 05:57:41

by Cong Wang

Subject: Re: [PATCH V2] fix array-index-out-of-bounds in taprio_change

On Mon, Aug 30, 2021 at 10:14 AM Jakub Kicinski <[email protected]> wrote:
>
> On Mon, 30 Aug 2021 11:30:06 +0000 [email protected]
> wrote:
> > Hello:
> >
> > This patch was applied to netdev/net-next.git (refs/heads/master):
> >
> > On Mon, 30 Aug 2021 11:47:01 +0800 you wrote:
> > > From: Haimin Zhang <[email protected]>
> > >
> > > 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.
> > >
> > > [...]
> >
> > Here is the summary with links:
> > - [V2] fix array-index-out-of-bounds in taprio_change
> > https://git.kernel.org/netdev/net-next/c/efe487fce306
> >
> > You are awesome, thank you!
>
> https://lore.kernel.org/netdev/20210830091046.610ceb1b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/
>
> Oh, well...

I agree it is slightly better to make the check work in
taprio_parse_mqprio_opt(), but this patch is not bad either, we
need to check the return value of netdev_set_num_tc() for
completeness at least.

BTW, this patch should be landed in -net, not -net-next, as it
fixes a real bug reported by syzbot.

Thanks.