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From: Phil Sutter <phil@nwl.cc>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org
Subject: Re: [iptables PATCH v2 00/17] Eliminate dedicated arptables-nft parser
Date: Fri, 15 Oct 2021 13:01:24 +0200	[thread overview]
Message-ID: <20211015110124.GL1668@orbyte.nwl.cc> (raw)
In-Reply-To: <YWiZacKr4s3mkdhU@salvia>

Hi Pablo,

On Thu, Oct 14, 2021 at 10:56:09PM +0200, Pablo Neira Ayuso wrote:
> On Thu, Sep 30, 2021 at 04:04:02PM +0200, Phil Sutter wrote:
> > Commandline parsing was widely identical with iptables and ip6tables.
> > This series adds the necessary code-changes to unify the parsers into a
> > common one.
> > 
> > Changes since v1:
> > - Fix patch 12, the parser has to check existence of proto_parse
> >   callback before dereferencing it. Otherwise arptables-nft segfaults if
> >   '-p' option is given.
> 
> LGTM.

Thanks for your review!

> > - Patches 13-17 add all the arptables quirks to restore compatibility
> >   with arptables-legacy. I didn't consider them important enough to push
> >   them unless someone complains. Yet breaking existing scripts is bad
> >   indeed. Please consider them RFC: If you consider (one of) them not
> >   important, please NACk and I will drop them before pushing.
> 
> For patch 13-16, you could display a warning for people to fix their
> scripts, so this particular (strange) behaviour in some cases can be
> dropped (at least, 13-15 look like left-over/bugs). For the
> check_inverse logic, I'd suggest to display a warning too, this is
> what it was done in iptables time ago to address this inconsistency.

I wonder how likely it is for someone to rely upon the behaviour. I can
imagine a script passing an empty interface name and expecting the
argument to be ignored (patch 13). Though what are the odds someone
actually calls arptables with '-m something' (patch 14) or a bogus table
name (patch 15)?

> I'd probably keep back patch 17/17, the max chain name length was
> reduced by when the revision field was introduced and this resulted in
> no issue being reported.

If that's OK with you, I would turn the empty interface name error into
a warning for arptables-nft, reintroduce the warning for intrapositioned
negations and drop the remaining quirks as they are likely hiding a bug.

Cheers, Phil

  reply	other threads:[~2021-10-15 11:01 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-30 14:04 [iptables PATCH v2 00/17] Eliminate dedicated arptables-nft parser Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 01/17] nft: Introduce builtin_tables_lookup() Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 02/17] xshared: Store optstring in xtables_globals Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 03/17] nft-shared: Introduce init_cs family ops callback Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 04/17] xtables: Simplify addr_mask freeing Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 05/17] nft: Add family ops callbacks wrapping different nft_cmd_* functions Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 06/17] xtables-standalone: Drop version number from init errors Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 07/17] libxtables: Introduce xtables_globals print_help callback Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 08/17] arptables: Use standard data structures when parsing Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 09/17] nft-arp: Introduce post_parse callback Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 10/17] nft-shared: Make nft_check_xt_legacy() family agnostic Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 11/17] xtables: Derive xtables_globals from family Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 12/17] nft: Merge xtables-arp-standalone.c into xtables-standalone.c Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 13/17] xtables: arptables doesn't warn about empty interface Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 14/17] xtables: arptables accepts but ignores '-m' Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 15/17] xtables: arptables ignores wrong -t values Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 16/17] xtables: Support '!' betwen option and argument Phil Sutter
2021-09-30 14:04 ` [iptables PATCH v2 17/17] nft: Store maximum allowed chain name length in family ops Phil Sutter
2021-10-14 20:56 ` [iptables PATCH v2 00/17] Eliminate dedicated arptables-nft parser Pablo Neira Ayuso
2021-10-15 11:01   ` Phil Sutter [this message]
2021-10-15 11:25     ` Pablo Neira Ayuso

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