net_sched: fix a use-after-free in tc_ctl_tfilter()

When tcf_destroy() returns true, tp could be already destroyed,
we should not use tp->next after that.

For long term, we probably should move tp list to list_head.

Fixes: 1e052be69d ("net_sched: destroy proto tp when all filters are gone")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
WANG Cong 2015-05-05 15:22:02 -07:00 committed by David S. Miller
parent 1006da19ea
commit d744318574

View File

@ -308,12 +308,11 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n)
case RTM_DELTFILTER:
err = tp->ops->delete(tp, fh);
if (err == 0) {
tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
if (tcf_destroy(tp, false)) {
struct tcf_proto *next = rtnl_dereference(tp->next);
struct tcf_proto *next = rtnl_dereference(tp->next);
tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
if (tcf_destroy(tp, false))
RCU_INIT_POINTER(*back, next);
}
}
goto errout;
case RTM_GETTFILTER: