netdev - [PATCH RFC 1/5] net/sched: fix refcount leak when 'goto

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Date:   Sat, 16 Feb 2019 00:06:27 +0100
From:   Davide Caratti <dcaratti@...hat.com>
To:     Jamal Hadi Salim <jhs@...atatu.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Vlad Buslov <vladbu@...lanox.com>,
        Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org
Subject: [PATCH RFC 1/5] net/sched: fix refcount leak when 'goto_chain' is used

when replacing valid 'goto chain' actions with another valid 'goto chain'
action, the kernel leaks chain->action_refcnt and chain->refcnt. Since we
unconditionally take the refcount again, if the control action is a 'goto
chain', we can just drop them after ->init() has ended successfully.

Fixes: db50514f9a9c ("net: sched: add termination action to allow goto chain")
Signed-off-by: Davide Caratti <dcaratti@...hat.com>
---
 net/sched/act_api.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index d4b8355737d8..91d79fac8cb2 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -907,6 +907,11 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 	if (err != ACT_P_CREATED)
 		module_put(a_o->owner);
 
+	if (a->goto_chain) {
+		tcf_action_goto_chain_fini(a);
+		a->goto_chain = NULL;
+	}
+
 	if (TC_ACT_EXT_CMP(a->tcfa_action, TC_ACT_GOTO_CHAIN)) {
 		err = tcf_action_goto_chain_init(a, tp);
 		if (err) {
-- 
2.20.1