Re: [PATCH nft 1/2] netfilter: nf_conntrack_sip: fix missing expect put in REGISTER path

[Florian Westphal <fw@strlen.de>]

Li Xiasong <lixiasong1@huawei.com> wrote:
> process_register_request() allocates an expectation, but the !helper
> error path returns NF_DROP without nf_ct_expect_put(exp).
> 
> Add the missing put to balance nf_ct_expect_alloc() on this path.
> 
> Fixes: e14575fa7529 ("netfilter: nf_conntrack: use rcu accessors where needed")
> Cc: stable@vger.kernel.org
> Signed-off-by: Li Xiasong <lixiasong1@huawei.com>
> ---
>  net/netfilter/nf_conntrack_sip.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
> index 1eb55907d470..a895bc836e1b 100644
> --- a/net/netfilter/nf_conntrack_sip.c
> +++ b/net/netfilter/nf_conntrack_sip.c
> @@ -1377,8 +1377,10 @@ static int process_register_request(struct sk_buff *skb, unsigned int protoff,
>  		saddr = &ct->tuplehash[!dir].tuple.src.u3;
>  
>  	helper = rcu_dereference(nfct_help(ct)->helper);
> -	if (!helper)
> +	if (!helper) {
> +		nf_ct_expect_put(exp);
>  		return NF_DROP;
> +	}

I think it would be simpler to move the rcu defer to before
exp allocation instead.