Commit 306381ae authored Jul 08, 2020 by Cong Wang Committed by David S. Miller Jul 09, 2020

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: 6529eaba ("net: sched: introduce tcf block infractructure")
Reported-and-tested-by:  <syzbot+d411cff6ab29cc2c311b@syzkaller.appspotmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 13cf8aab

net/sched/sch_atm.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -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;
		}

Admin message