Re: ebtables-nft can't delete complex rules by specifying complete rule with kernel 6.3+

[Florian Westphal <fw@strlen.de>]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> On Mon, Jul 10, 2023 at 04:41:27PM +0200, Igor Raits wrote:
> > Hello Florian,
> > 
> > On Mon, Jul 10, 2023 at 2:49 PM Florian Westphal <fw@strlen.de> wrote:
> > >
> > > Florian Westphal <fw@strlen.de> wrote:
> > > > Igor Raits <igor@gooddata.com> wrote:
> > > > > Hello,
> > > > >
> > > > > We started to observe the issue regarding ebtables-nft and how it
> > > > > can't wipe rules when specifying full rule. Removing the rule by index
> > > > > works fine, though. Also with kernel 6.1.y it works completely fine.
> > > > >
> > > > > I've started with 1.8.8 provided in CentOS Stream 9, then tried the
> > > > > latest git version and all behave exactly the same. See the behavior
> > > > > below. As you can see, simple DROP works, but more complex one do not.
> > > > >
> > > > > As bugzilla requires some special sign-up procedure, apologize for
> > > > > reporting it directly here in the ML.
> > > >
> > > > Thanks for the report, I'll look into it later today.
> > >
> > > Its a bug in ebtables-nft, it fails to delete the rule since
> > >
> > > 938154b93be8cd611ddfd7bafc1849f3c4355201,
> > > netfilter: nf_tables: reject unbound anonymous set before commit phase
> > >
> > > But its possible do remove the rule via
> > > nft delete rule .. handle $x
> > >
> > > so the breakge is limited to ebtables-nft.
> > 
> > Thanks for confirmation and additional information regarding where
> > exactly the issue was introduced.
> > The ebtables-nft (well, ebtables in general) is heavily used by the
> > OpenStack Neutron (in linuxbridge mode), so this breaks our setup
> > quite a bit. Would you recommend to revert kernel change or would you
> > have the actual fix soon (ebtables-nft or kernel)?
> 
> Just to make sure this bug is not caused by something else.

No no no, this is a userspace bug.
netfilter: nf_tables: reject unbound anonymous set before commit phase

ebtables-nft emits a DELRULE followed by creation of a (dangling!)
anon set, because backend code that handles add/delete is identical,
so 'delete' request for among schedules addition of the set.