Subject: Re: [PATCH] net: sched: act_ct: fix possible refcount leak in tcf_ct_init()

From: Jakub Kicinski <[email-masked]>
Date: Thu, 22 Sep 2022 07:14:48 -0700

On Wed, 21 Sep 2022 17:06:00 +0800 Hangyu Hua wrote:
> Subject: [PATCH] net: sched: act_ct: fix possible refcount leak in tcf_ct_init()

[PATCH net] please

> nf_ct_put need to be called to put the refcount got by tcf_ct_fill_params
> to avoid possible refcount leak when tcf_ct_flow_table_get fails.
> 
> Fixes: c34b961a2492 ("net/sched: act_ct: Create nf flow table per zone")
> Signed-off-by: Hangyu Hua <[email-masked]>
> ---
>  net/sched/act_ct.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
> index d55afb8d14be..3646956fc717 100644
> --- a/net/sched/act_ct.c
> +++ b/net/sched/act_ct.c
> @@ -1412,6 +1412,8 @@ static int tcf_ct_init(struct net *net, struct nlattr *nla,
>  cleanup:
>  	if (goto_ch)
>  		tcf_chain_put_by_act(goto_ch);
> +	if (params->tmpl)
> +		nf_ct_put(params->tmpl);

This is buggy, params could be NULL here. Please add a new label above
cleanup (cleanup_params for example) and make the
tcf_ct_flow_table_get() failure path jump there instead.