From: Phil Sutter <phil@nwl.cc>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Arturo Borrero Gonzalez <arturo@netfilter.org>,
netfilter-devel@vger.kernel.org
Subject: Re: [iptables PATCH] iptables-nft: fix basechain policy configuration
Date: Fri, 2 Oct 2020 14:28:52 +0200 [thread overview]
Message-ID: <20201002122852.GC29050@orbyte.nwl.cc> (raw)
In-Reply-To: <20201002121558.GA1367@salvia>
On Fri, Oct 02, 2020 at 02:15:58PM +0200, Pablo Neira Ayuso wrote:
> On Fri, Oct 02, 2020 at 02:07:32PM +0200, Phil Sutter wrote:
> > Hi,
> >
> > On Fri, Oct 02, 2020 at 01:44:36PM +0200, Arturo Borrero Gonzalez wrote:
> > > Previous to this patch, the basechain policy could not be properly configured if it wasn't
> > > explictly set when loading the ruleset, leading to iptables-nft-restore (and ip6tables-nft-restore)
> > > trying to send an invalid ruleset to the kernel.
> >
> > I fear this is not sufficient: iptables-legacy-restore leaves the
> > previous chain policy in place if '-' is given in dump file. Please try
> > this snippet from a testcase I wrote:
> >
> > $XT_MULTI iptables -P FORWARD DROP
> >
> > diff -u -Z <($XT_MULTI iptables-save | grep '^:FORWARD') \
> > <(echo ":FORWARD DROP [0:0]")
> >
> > $XT_MULTI iptables-restore -c <<< "$TEST_RULESET"
> > diff -u -Z <($XT_MULTI iptables-save | grep '^:FORWARD') \
> > <(echo ":FORWARD DROP [0:0]")
>
> Hm, this is how it works in this patch right?
>
> I mean, if '-' is given, chain policy attribute in the netlink message
> is not set, and the kernel sets chain policy to
> NFT_CHAIN_POLICY_UNSET.
>
> Or am I missing anything?
This is *flushing* iptables-restore. We're dropping the chain first and
then reinstall it.
Another quirk is that iptables-legacy-restore ignores the counters if
policy is '-' even if --counters flag was given. (:
Cheers, Phil
next prev parent reply other threads:[~2020-10-02 12:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-02 11:44 [iptables PATCH] iptables-nft: fix basechain policy configuration Arturo Borrero Gonzalez
2020-10-02 12:07 ` Phil Sutter
2020-10-02 12:15 ` Pablo Neira Ayuso
2020-10-02 12:28 ` Phil Sutter [this message]
2020-10-02 12:47 ` Pablo Neira Ayuso
2020-10-02 13:31 ` Phil Sutter
2020-10-02 14:39 ` Pablo Neira Ayuso
2020-10-08 17:31 ` Pablo Neira Ayuso
2020-10-09 8:29 ` Phil Sutter
2020-10-09 8:50 ` Pablo Neira Ayuso
2020-10-09 9:37 ` Phil Sutter
2020-10-09 10:07 ` Reindl Harald
2020-10-09 10:14 ` Phil Sutter
2020-10-09 10:28 ` Reindl Harald
2020-10-09 10:37 ` Jozsef Kadlecsik
2020-10-09 12:04 ` Phil Sutter
2020-10-09 19:05 ` Jozsef Kadlecsik
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