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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>,
	Jiri Pirko <jiri@resnulli.us>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Mohit Bhasi <mohitbhasi1998@gmail.com>,
	"Mohit P. Tahiliani" <tahiliani@nitk.edu.in>,
	"V. Saicharan" <vsaicharan1998@gmail.com>,
	Gautam Ramakrishnan <gautamramk@gmail.com>,
	netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH net] net: sched: prevent a use after free
Date: Fri, 31 Jan 2020 09:56:47 +0300	[thread overview]
Message-ID: <20200131065647.joonbg3wzcw26x3b@kili.mountain> (raw)

The code calls kfree_skb(skb); and then re-uses "skb" on the next line.
Let's re-order these lines to solve the problem.

Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 net/sched/sch_fq_pie.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c
index bbd0dea6b6b9..78472e0773e9 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;
+		kfree_skb(skb);
 	}
 	qdisc_tree_reduce_backlog(sch, num_dropped, len_dropped);
 
-- 
2.11.0


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>,
	Jiri Pirko <jiri@resnulli.us>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Mohit Bhasi <mohitbhasi1998@gmail.com>,
	"Mohit P. Tahiliani" <tahiliani@nitk.edu.in>,
	"V. Saicharan" <vsaicharan1998@gmail.com>,
	Gautam Ramakrishnan <gautamramk@gmail.com>,
	netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH net] net: sched: prevent a use after free
Date: Fri, 31 Jan 2020 06:56:47 +0000	[thread overview]
Message-ID: <20200131065647.joonbg3wzcw26x3b@kili.mountain> (raw)

The code calls kfree_skb(skb); and then re-uses "skb" on the next line.
Let's re-order these lines to solve the problem.

Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 net/sched/sch_fq_pie.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c
index bbd0dea6b6b9..78472e0773e9 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;
+		kfree_skb(skb);
 	}
 	qdisc_tree_reduce_backlog(sch, num_dropped, len_dropped);
 
-- 
2.11.0

             reply	other threads:[~2020-01-31  6:57 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-31  6:56 Dan Carpenter [this message]
2020-01-31  6:56 ` [PATCH net] net: sched: prevent a use after free Dan Carpenter
2020-02-01 19:38 ` Cong Wang
2020-02-01 19:38   ` Cong Wang
2020-02-03  8:38   ` Dan Carpenter
2020-02-03  8:38     ` Dan Carpenter
2020-02-03 19:58     ` Cong Wang
2020-02-03 19:58       ` Cong Wang
2020-02-03 20:33       ` Cong Wang
2020-02-03 20:33         ` Cong Wang
2020-02-05 11:53         ` [PATCH v2 " Dan Carpenter
2020-02-05 11:53           ` Dan Carpenter
2020-02-05 18:03           ` Cong Wang
2020-02-05 18:03             ` Cong Wang
2020-02-06 13:01           ` David Miller
2020-02-06 13:01             ` David Miller

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