Re: [PATCH nf] netfilter: conntrack: restore IPS_CONFIRMED out of nf_conntrack_hash_check_insert()

[Florian Westphal <fw@strlen.de>]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> e6d57e9ff0ae ("netfilter: conntrack: fix rmmod double-free race")
> consolidates IPS_CONFIRMED bit set in nf_conntrack_hash_check_insert().
> However, this breaks ctnetlink:
> 
>  # conntrack -I -p tcp --timeout 123 --src 1.2.3.4 --dst 5.6.7.8 --state ESTABLISHED --sport 1 --dport 4 -u SEEN_REPLY
>  conntrack v1.4.6 (conntrack-tools): Operation failed: Device or resource busy
> 
> This is a partial revert of the aforementioned commit.
> 
> Fixes: e6d57e9ff0ae ("netfilter: conntrack: fix rmmod double-free race")
> Reported-by: Stéphane Graber <stgraber@stgraber.org>
> Tested-by: Stéphane Graber <stgraber@stgraber.org>
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
>  net/netfilter/nf_conntrack_bpf.c     | 1 +
>  net/netfilter/nf_conntrack_core.c    | 1 -
>  net/netfilter/nf_conntrack_netlink.c | 3 +++
>  3 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> index bfc3aaa2c872..d3ee18854698 100644
> --- a/net/netfilter/nf_conntrack_netlink.c
> +++ b/net/netfilter/nf_conntrack_netlink.c
> @@ -2316,6 +2316,9 @@ ctnetlink_create_conntrack(struct net *net,
>  	nfct_seqadj_ext_add(ct);
>  	nfct_synproxy_ext_add(ct);
>  
> +	/* we must add conntrack extensions before confirmation. */
> +	ct->status |= IPS_CONFIRMED;
> +

I'd guess that these 2 lines are the only part that is needed, but up
to you.