net_sched: fix a memory leak in atm_tc_init()

[ Upstream commit 306381aec7c2b5a658eebca008c8a1b666536cba ]

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: 6529eaba33 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Cong Wang 2020-07-08 20:13:59 -07:00 committed by Greg Kroah-Hartman
parent 5c6e5496a7
commit 1343c53945

View file

@ -551,16 +551,16 @@ 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;
}