netdev - [PATCH net-next 1/2] net: sched: fix the err path of tcf_ct_init in act

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Date:   Fri, 23 Sep 2022 11:28:26 -0400
From:   Xin Long <lucien.xin@...il.com>
To:     network dev <netdev@...r.kernel.org>
Cc:     davem@...emloft.net, kuba@...nel.org,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
        Davide Caratti <dcaratti@...hat.com>,
        Oz Shlomo <ozsh@...dia.com>, Paul Blakey <paulb@...dia.com>,
        Ilya Maximets <i.maximets@....org>
Subject: [PATCH net-next 1/2] net: sched: fix the err path of tcf_ct_init in act_ct

When it returns err from tcf_ct_flow_table_get(), the param tmpl should
have been freed in the cleanup. Otherwise a memory leak will occur.

While fixing this problem, this patch also makes the err path simple by
calling tcf_ct_params_free(), so that it won't cause problems when more
members are added into param and need freeing on the err path.

Fixes: c34b961a2492 ("net/sched: act_ct: Create nf flow table per zone")
Signed-off-by: Xin Long <lucien.xin@...il.com>
---
 net/sched/act_ct.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
index 9d19710835b0..193a460a9d7f 100644
--- a/net/sched/act_ct.c
+++ b/net/sched/act_ct.c
@@ -345,11 +345,9 @@ static void tcf_ct_flow_table_cleanup_work(struct work_struct *work)
 	module_put(THIS_MODULE);
 }
 
-static void tcf_ct_flow_table_put(struct tcf_ct_params *params)
+static void tcf_ct_flow_table_put(struct tcf_ct_flow_table *ct_ft)
 {
-	struct tcf_ct_flow_table *ct_ft = params->ct_ft;
-
-	if (refcount_dec_and_test(&params->ct_ft->ref)) {
+	if (refcount_dec_and_test(&ct_ft->ref)) {
 		rhashtable_remove_fast(&zones_ht, &ct_ft->node, zones_params);
 		INIT_RCU_WORK(&ct_ft->rwork, tcf_ct_flow_table_cleanup_work);
 		queue_rcu_work(act_ct_wq, &ct_ft->rwork);
@@ -832,18 +830,23 @@ static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
 	return err;
 }
 
-static void tcf_ct_params_free(struct rcu_head *head)
+static void tcf_ct_params_free(struct tcf_ct_params *params)
 {
-	struct tcf_ct_params *params = container_of(head,
-						    struct tcf_ct_params, rcu);
-
-	tcf_ct_flow_table_put(params);
-
+	if (params->ct_ft)
+		tcf_ct_flow_table_put(params->ct_ft);
 	if (params->tmpl)
 		nf_ct_put(params->tmpl);
 	kfree(params);
 }
 
+static void tcf_ct_params_free_rcu(struct rcu_head *head)
+{
+	struct tcf_ct_params *params;
+
+	params = container_of(head, struct tcf_ct_params, rcu);
+	tcf_ct_params_free(params);
+}
+
 #if IS_ENABLED(CONFIG_NF_NAT)
 /* Modelled after nf_nat_ipv[46]_fn().
  * range is only used for new, uninitialized NAT state.
@@ -1401,14 +1404,15 @@ static int tcf_ct_init(struct net *net, struct nlattr *nla,
 	if (goto_ch)
 		tcf_chain_put_by_act(goto_ch);
 	if (params)
-		call_rcu(&params->rcu, tcf_ct_params_free);
+		call_rcu(&params->rcu, tcf_ct_params_free_rcu);
 
 	return res;
 
 cleanup:
 	if (goto_ch)
 		tcf_chain_put_by_act(goto_ch);
-	kfree(params);
+	if (params)
+		tcf_ct_params_free(params);
 	tcf_idr_release(*a, bind);
 	return err;
 }
@@ -1420,7 +1424,7 @@ static void tcf_ct_cleanup(struct tc_action *a)
 
 	params = rcu_dereference_protected(c->params, 1);
 	if (params)
-		call_rcu(&params->rcu, tcf_ct_params_free);
+		call_rcu(&params->rcu, tcf_ct_params_free_rcu);
 }
 
 static int tcf_ct_dump_key_val(struct sk_buff *skb,
-- 
2.31.1