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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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        Jiri Pirko <jiri@resnulli.us>, Terry Lam <vtlam@google.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.19 10/50] sch_hhf: ensure quantum and hhf_non_hh_weight are non-zero
Date:   Wed, 18 Sep 2019 08:18:53 +0200
Message-Id: <20190918061223.977323020@linuxfoundation.org>
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From: Cong Wang <xiyou.wangcong@gmail.com>

[ Upstream commit d4d6ec6dac07f263f06d847d6f732d6855522845 ]

In case of TCA_HHF_NON_HH_WEIGHT or TCA_HHF_QUANTUM is zero,
it would make no progress inside the loop in hhf_dequeue() thus
kernel would get stuck.

Fix this by checking this corner case in hhf_change().

Fixes: 10239edf86f1 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
Reported-by: syzbot+bc6297c11f19ee807dc2@syzkaller.appspotmail.com
Reported-by: syzbot+041483004a7f45f1f20a@syzkaller.appspotmail.com
Reported-by: syzbot+55be5f513bed37fc4367@syzkaller.appspotmail.com
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Terry Lam <vtlam@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sched/sch_hhf.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sched/sch_hhf.c
+++ b/net/sched/sch_hhf.c
@@ -529,7 +529,7 @@ static int hhf_change(struct Qdisc *sch,
 		new_hhf_non_hh_weight = nla_get_u32(tb[TCA_HHF_NON_HH_WEIGHT]);
 
 	non_hh_quantum = (u64)new_quantum * new_hhf_non_hh_weight;
-	if (non_hh_quantum > INT_MAX)
+	if (non_hh_quantum == 0 || non_hh_quantum > INT_MAX)
 		return -EINVAL;
 
 	sch_tree_lock(sch);