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From:   Ivan Vecera <ivecera@redhat.com>
To:     netdev@vger.kernel.org
Cc:     Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Paul Blakey <paulb@nvidia.com>,
        Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH net] net/sched: cls_api: Initialize miss_cookie_node when action miss is not used
Date:   Thu, 20 Apr 2023 19:59:52 +0200
Message-Id: <20230420175952.1114302-1-ivecera@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Function tcf_exts_init_ex() sets exts->miss_cookie_node ptr only
when use_action_miss is true so it assumes in other case that
the field is set to NULL by the caller. If not then the field
contains garbage and subsequent tcf_exts_destroy() call results
in a crash.
Initialize .miss_cookie_node pointer to NULL when use_action_miss
parameter is false to avoid this potential scenario.

Fixes: 80cd22c35c90 ("net/sched: cls_api: Support hardware miss to tc action")
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
 net/sched/cls_api.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 35785a36c80298..8bc5b9d6a2916e 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -3224,8 +3224,12 @@ int tcf_exts_init_ex(struct tcf_exts *exts, struct net *net, int action,
 	exts->action = action;
 	exts->police = police;
 
-	if (!use_action_miss)
+	if (!use_action_miss) {
+#ifdef CONFIG_NET_CLS_ACT
+		exts->miss_cookie_node = NULL;
+#endif
 		return 0;
+	}
 
 	err = tcf_exts_miss_cookie_base_alloc(exts, tp, handle);
 	if (err)
-- 
2.39.2