netdev - [Patch net] net_sched: fix a memory leak in atm_tc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200709031359.11063-1-xiyou.wangcong@gmail.com>
Date:   Wed,  8 Jul 2020 20:13:59 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     netdev@...r.kernel.org
Cc:     Cong Wang <xiyou.wangcong@...il.com>,
        syzbot+d411cff6ab29cc2c311b@...kaller.appspotmail.com,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Jiri Pirko <jiri@...nulli.us>
Subject: [Patch net] net_sched: fix a memory leak in atm_tc_init()

When tcf_block_get() fails inside atm_tc_init(),
atm_tc_put() is called to release the qdisc p->link.q.
But the flow->ref prevents it to do so, as the flow->ref
is still zero.

Fix this by moving the p->link.ref initialization before
tcf_block_get().

Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
Reported-and-tested-by: syzbot+d411cff6ab29cc2c311b@...kaller.appspotmail.com
Cc: Jamal Hadi Salim <jhs@...atatu.com>
Cc: Jiri Pirko <jiri@...nulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
 net/sched/sch_atm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index ee12ca9f55b4..1c281cc81f57 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -553,16 +553,16 @@ static int atm_tc_init(struct Qdisc *sch, struct nlattr *opt,
 	if (!p->link.q)
 		p->link.q = &noop_qdisc;
 	pr_debug("atm_tc_init: link (%p) qdisc %p\n", &p->link, p->link.q);
+	p->link.vcc = NULL;
+	p->link.sock = NULL;
+	p->link.common.classid = sch->handle;
+	p->link.ref = 1;
 
 	err = tcf_block_get(&p->link.block, &p->link.filter_list, sch,
 			    extack);
 	if (err)
 		return err;
 
-	p->link.vcc = NULL;
-	p->link.sock = NULL;
-	p->link.common.classid = sch->handle;
-	p->link.ref = 1;
 	tasklet_init(&p->task, sch_atm_dequeue, (unsigned long)sch);
 	return 0;
 }
-- 
2.27.0