Commit 21de12ee authored Jun 20, 2016 by Eric Dumazet Committed by David S. Miller Jun 23, 2016

netem: fix a use after free



If the packet was dropped by lower qdisc, then we must not
access it later.

Save qdisc_pkt_len(skb) in a temp variable.

Fixes: 2ccccf5f ("net_sched: update hierarchical backlog too")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 817e9f2c

net/sched/sch_netem.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -650,14 +650,14 @@ static struct sk_buff netem_dequeue(struct Qdisc sch)
		#endif

		if (q->qdisc) {
		unsigned int pkt_len = qdisc_pkt_len(skb);
		int err = qdisc_enqueue(skb, q->qdisc);

		if (unlikely(err != NET_XMIT_SUCCESS)) {
		if (net_xmit_drop_count(err)) {
		if (err != NET_XMIT_SUCCESS &&
		net_xmit_drop_count(err)) {
		qdisc_qstats_drop(sch);
		qdisc_tree_reduce_backlog(sch, 1,
		qdisc_pkt_len(skb));
		}
		pkt_len);
		}
		goto tfifo_dequeue;
		}