From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Sun, 8 Sep 2019 19:11:23 +0000 (-0700)
Subject: net_sched: check cops->tcf_block in tc_bind_tclass()
X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~2119^2~22
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=8b142a00edcf8422ca48b8de88d286efb500cb53;p=mirror_ubuntu-focal-kernel.git

net_sched: check cops->tcf_block in tc_bind_tclass()

At least sch_red and sch_tbf don't implement ->tcf_block()
while still have a non-zero tc "class".

Instead of adding nop implementations to each of such qdisc's,
we can just relax the check of cops->tcf_block() in
tc_bind_tclass(). They don't support TC filter anyway.

Reported-by: syzbot+21b29db13c065852f64b@syzkaller.appspotmail.com
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 04faee7ccbce..1047825d9f48 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1920,6 +1920,8 @@ static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
 	cl = cops->find(q, portid);
 	if (!cl)
 		return;
+	if (!cops->tcf_block)
+		return;
 	block = cops->tcf_block(q, cl, NULL);
 	if (!block)
 		return;