net sched actions: fix refcnt leak in skbmod

When application fails to pass flags in netlink TLV when replacing
existing skbmod action, the kernel will leak refcnt:

$ tc actions get action skbmod index 1
total acts 0

        action order 0: skbmod pipe set smac 00:11:22:33:44:55
         index 1 ref 1 bind 0

For example, at this point a buggy application replaces the action with
index 1 with new smac 00:aa:22:33:44:55, it fails because of zero flags,
however refcnt gets bumped:

$ tc actions get actions skbmod index 1
total acts 0

        action order 0: skbmod pipe set smac 00:11:22:33:44:55
         index 1 ref 2 bind 0
$

Tha patch fixes this by calling tcf_idr_release() on existing actions.

Fixes: 86da71b573 ("net_sched: Introduce skbmod action")
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Roman Mashak 2018-05-11 14:35:33 -04:00 committed by David S. Miller
parent d68d75fdc3
commit a52956dfc5

View File

@ -131,8 +131,11 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
if (exists && bind)
return 0;
if (!lflags)
if (!lflags) {
if (exists)
tcf_idr_release(*a, bind);
return -EINVAL;
}
if (!exists) {
ret = tcf_idr_create(tn, parm->index, est, a,