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

From: tcs . kernel
Date: Sun Aug 29 2021 - 23:47:36 EST


From: Haimin Zhang <tcs_kernel@xxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Haimin Zhang <tcs_kernel@xxxxxxxxxxx>
---
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