Re: [PATCH nf V3] netfilter: nf_ct_helper: permit cthelpers with different names via nfnetlink

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

On Sat, Apr 15, 2017 at 07:27:42PM +0800, Liping Zhang wrote:
> From: Liping Zhang <zlpnobody@gmail.com>
> 
> cthelpers added via nfnetlink may have the same tuple, i.e. except for
> the l3proto and l4proto, other fields are all zero. So even with the
> different names, we will also fail to add them:
>   # nfct helper add ssdp inet udp
>   # nfct helper add tftp inet udp
>   nfct v1.4.3: netlink error: File exists
> 
> So in order to avoid unpredictable behaviour, we should:
> 1. cthelpers can be selected by nft ct helper obj or xt_CT target, so
> report error if duplicated { name, l3proto, l4proto } tuple exist.
> 2. cthelpers can be selected by nf_ct_tuple_src_mask_cmp when
> nf_ct_auto_assign_helper is enabled, so also report error if duplicated
> { l3proto, l4proto, src-port } tuple exist.
> 
> Also note, if the cthelper is added from userspace, then the src-port will
> always be zero, it's invalid for nf_ct_auto_assign_helper, so there's no
> need to check the second point listed above.

Applied, thanks.