From f6bab199315b70fd83fe3ee0947bc84c7a35f3d4 Mon Sep 17 00:00:00 2001 From: Toke Høiland-Jørgensen Date: Wed, 9 Jan 2019 17:09:42 +0100 Subject: sched: Avoid dereferencing skb pointer after child enqueue MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Parent qdiscs may dereference the pointer to the enqueued skb after enqueue. However, both CAKE and TBF call consume_skb() on the original skb when splitting GSO packets, leading to a potential use-after-free in the parent. Fix this by avoiding dereferencing the skb pointer after enqueueing to the child. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller --- net/sched/sch_cbs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/sched/sch_cbs.c') diff --git a/net/sched/sch_cbs.c b/net/sched/sch_cbs.c index e689e11b6d0f..c6a502933fe7 100644 --- a/net/sched/sch_cbs.c +++ b/net/sched/sch_cbs.c @@ -88,13 +88,14 @@ static int cbs_child_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct Qdisc *child, struct sk_buff **to_free) { + unsigned int len = qdisc_pkt_len(skb); int err; err = child->ops->enqueue(skb, child, to_free); if (err != NET_XMIT_SUCCESS) return err; - qdisc_qstats_backlog_inc(sch, skb); + sch->qstats.backlog += len; sch->q.qlen++; return NET_XMIT_SUCCESS; -- cgit v1.2.3-59-g8ed1b