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authorDan Carpenter <dan.carpenter@oracle.com>2020-02-05 14:53:30 +0300
committerDavid S. Miller <davem@davemloft.net>2020-02-06 14:00:12 +0100
commit7a02ea65027523386ab4ba4af0ab93497b3073df (patch)
treeb37ff5686ea87247c68728945fe03d13addb3ef4
parent86b18aaa2b5b5bb48e609cd591b3d2d0fdbe0442 (diff)
downloadlinux-7a02ea65027523386ab4ba4af0ab93497b3073df.tar.gz
net: sched: prevent a use after free
The bug is that we call kfree_skb(skb) and then pass "skb" to qdisc_pkt_len(skb) on the next line, which is a use after free. Also Cong Wang points out that it's better to delay the actual frees until we drop the rtnl lock so we should use rtnl_kfree_skbs() instead of kfree_skb(). Cc: Cong Wang <xiyou.wangcong@gmail.com> Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/sched/sch_fq_pie.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c
index bbd0dea6b6b98e..214657eb3dfdf2 100644
--- a/net/sched/sch_fq_pie.c
+++ b/net/sched/sch_fq_pie.c
@@ -349,9 +349,9 @@ static int fq_pie_change(struct Qdisc *sch, struct nlattr *opt,
while (sch->q.qlen > sch->limit) {
struct sk_buff *skb = fq_pie_qdisc_dequeue(sch);
- kfree_skb(skb);
len_dropped += qdisc_pkt_len(skb);
num_dropped += 1;
+ rtnl_kfree_skbs(skb, skb);
}
qdisc_tree_reduce_backlog(sch, num_dropped, len_dropped);