sched: Avoid dereferencing skb pointer after child enqueue
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 <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index f6f4807..4247146 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -199,6 +199,7 @@ static struct tcf_block *dsmark_tcf_block(struct Qdisc *sch, unsigned long cl,
static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
+ unsigned int len = qdisc_pkt_len(skb);
struct dsmark_qdisc_data *p = qdisc_priv(sch);
int err;
@@ -271,7 +272,7 @@ static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch,
return err;
}
- qdisc_qstats_backlog_inc(sch, skb);
+ sch->qstats.backlog += len;
sch->q.qlen++;
return NET_XMIT_SUCCESS;