Re: [PATCH nf 5/5] netfilter: nfnl_cthelper: fix a race when walk the nf_ct_helper_hash table

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Tue, Mar 21, 2017 at 11:19:11PM +0800, Liping Zhang wrote:
> Hi Pablo,
> 
> 2017-03-21 22:48 GMT+08:00 Liping Zhang <zlpnobody@gmail.com>:
> > 2017-03-21 18:33 GMT+08:00 Pablo Neira Ayuso <pablo@netfilter.org>:
> >>> +struct nfnl_cthelper {
> >>> +     struct list_head                list;
> >>> +     struct nf_conntrack_helper      *helper;
> >>> +};
> >>> +
> >>> +static LIST_HEAD(nfnl_cthelper_list);
> >>
> >> We need a field possible_net_t so we can store what netns this helper
> >> belongs to, thus in case of flush command, we just remove the helpers
> >> that this netns owns.
> 
> After I have a closer look, I find that we do not support netns for the
> nfct_helper currently. So this possible_net_t field is not necessary for
> the time being.

Oh, I see. This is probably one of the remaining subsystems not having
netns support.

> I have a quick glance look, supporting netns for helper need a lot works
> to do. We need to both change the nfnetlink_cthelper, nf_conntrack_help
> and so on.
> 
> But if you think it's worth to support netns for cthelper, I can
> finish it in my spare time:)

Let's focus on fixing up the existing issues. It would be great if you
can add that later on, once changes in nf.git propagate to
nf-next.git.

BTW, let me also pushed out what I have here into nf.git. I'd
appreciate if you can rebase this 5/5 patch on top of it.

Thanks!