[PATCH 4.19 10/50] sch_hhf: ensure quantum and hhf_non_hh_weight are non-zero

Greg Kroah-Hartman
2019-09-18T06:22:06Z

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);