diff options
| author | Toke Høiland-Jørgensen <toke@redhat.com> | 2019-01-09 17:09:42 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-01-15 20:12:00 -0800 |
| commit | f6bab199315b70fd83fe3ee0947bc84c7a35f3d4 (patch) | |
| tree | c662d696e0bfe2ee2be86cbdf0da095d9d6389ba /net/sched/sch_qfq.c | |
| parent | 80b3671e9377916bf2b02e56113fa7377ce5705a (diff) | |
| download | lwn-f6bab199315b70fd83fe3ee0947bc84c7a35f3d4.tar.gz lwn-f6bab199315b70fd83fe3ee0947bc84c7a35f3d4.zip | |
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>
Diffstat (limited to 'net/sched/sch_qfq.c')
| -rw-r--r-- | net/sched/sch_qfq.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c index dc37c4ead439..8d5e55d5bed2 100644 --- a/net/sched/sch_qfq.c +++ b/net/sched/sch_qfq.c @@ -1210,6 +1210,7 @@ static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *q) static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) { + unsigned int len = qdisc_pkt_len(skb), gso_segs; struct qfq_sched *q = qdisc_priv(sch); struct qfq_class *cl; struct qfq_aggregate *agg; @@ -1224,17 +1225,17 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, } pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid); - if (unlikely(cl->agg->lmax < qdisc_pkt_len(skb))) { + if (unlikely(cl->agg->lmax < len)) { pr_debug("qfq: increasing maxpkt from %u to %u for class %u", - cl->agg->lmax, qdisc_pkt_len(skb), cl->common.classid); - err = qfq_change_agg(sch, cl, cl->agg->class_weight, - qdisc_pkt_len(skb)); + cl->agg->lmax, len, cl->common.classid); + err = qfq_change_agg(sch, cl, cl->agg->class_weight, len); if (err) { cl->qstats.drops++; return qdisc_drop(skb, sch, to_free); } } + gso_segs = skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1; err = qdisc_enqueue(skb, cl->qdisc, to_free); if (unlikely(err != NET_XMIT_SUCCESS)) { pr_debug("qfq_enqueue: enqueue failed %d\n", err); @@ -1245,8 +1246,9 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, return err; } - bstats_update(&cl->bstats, skb); - qdisc_qstats_backlog_inc(sch, skb); + cl->bstats.bytes += len; + cl->bstats.packets += gso_segs; + sch->qstats.backlog += len; ++sch->q.qlen; agg = cl->agg; @@ -1254,7 +1256,7 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, if (cl->qdisc->q.qlen != 1) { if (unlikely(skb == cl->qdisc->ops->peek(cl->qdisc)) && list_first_entry(&agg->active, struct qfq_class, alist) - == cl && cl->deficit < qdisc_pkt_len(skb)) + == cl && cl->deficit < len) list_move_tail(&cl->alist, &agg->active); return err; |