diff mbox series

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

Message ID 1630295221-9859-1-git-send-email-tcs_kernel@tencent.com
State New
Headers show
Series [V2] fix array-index-out-of-bounds in taprio_change | expand

Commit Message

Haimin Zhang Aug. 30, 2021, 3:47 a.m. UTC 
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(-)

Comments

Cong Wang Aug. 31, 2021, 5:56 a.m. UTC | #1 
On Mon, Aug 30, 2021 at 10:14 AM Jakub Kicinski <kuba@kernel.org> wrote:
>

> On Mon, 30 Aug 2021 11:30:06 +0000 patchwork-bot+netdevbpf@kernel.org

> 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 <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.

> > >

> > > [...]

> >

> > 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.
diff mbox series

Patch

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],