| From foo@baz Wed Jul 6 16:50:56 PDT 2016 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Mon, 20 Jun 2016 15:00:43 -0700 |
| Subject: netem: fix a use after free |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| [ Upstream commit 21de12ee5568fd1aec47890c72967abf791ac80a ] |
| |
| 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: 2ccccf5fb43f ("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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/sched/sch_netem.c | 12 ++++++------ |
| 1 file changed, 6 insertions(+), 6 deletions(-) |
| |
| --- a/net/sched/sch_netem.c |
| +++ b/net/sched/sch_netem.c |
| @@ -650,14 +650,14 @@ deliver: |
| #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)) { |
| - qdisc_qstats_drop(sch); |
| - qdisc_tree_reduce_backlog(sch, 1, |
| - qdisc_pkt_len(skb)); |
| - } |
| + if (err != NET_XMIT_SUCCESS && |
| + net_xmit_drop_count(err)) { |
| + qdisc_qstats_drop(sch); |
| + qdisc_tree_reduce_backlog(sch, 1, |
| + pkt_len); |
| } |
| goto tfifo_dequeue; |
| } |
