[PATCH AUTOSEL 5.14 250/252] fix array-index-out-of-bounds in taprio_change

Sasha Levin
2021-09-09T12:06:12Z

From: Haimin Zhang <tcs_kernel@tencent.com>

[ Upstream commit efe487fce3061d94222c6501d7be3aa549b3dc78 ]

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 9c79374457a0..1ab2fc933a21 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],
--
2.30.2