[PATCH v5 net 1/6] net/sched: sch_ingress: Only create under TC_H_INGRESS

Peilin Ye
2023-05-24T01:18:11Z

From: Peilin Ye <peilin.ye@bytedance.com>

ingress Qdiscs are only supposed to be created under TC_H_INGRESS.
Return -EOPNOTSUPP if 'parent' is not TC_H_INGRESS, similar to
mq_init().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+b53a9c0d1ea4ad62da8b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/0000000000006cf87705f79acf1a@google.com/
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
---
change in v5:
- avoid underflowing @ingress_needed_key in ->destroy(), reported by
Pedro

change in v3, v4:
- add in-body From: tag

net/sched/sch_ingress.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
index 84838128b9c5..f9ef6deb2770 100644
--- a/net/sched/sch_ingress.c
+++ b/net/sched/sch_ingress.c
@@ -80,6 +80,9 @@ static int ingress_init(struct Qdisc *sch, struct nlattr *opt,
struct net_device *dev = qdisc_dev(sch);
int err;

+ if (sch->parent != TC_H_INGRESS)
+ return -EOPNOTSUPP;
+
net_inc_ingress_queue();

mini_qdisc_pair_init(&q->miniqp, sch, &dev->miniq_ingress);
@@ -101,6 +104,9 @@ static void ingress_destroy(struct Qdisc *sch)
{
struct ingress_sched_data *q = qdisc_priv(sch);

+ if (sch->parent != TC_H_INGRESS)
+ return;
+
tcf_block_put_ext(q->block, sch, &q->block_info);
net_dec_ingress_queue();
}
--
2.20.1