From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Phil Sutter <phil@nwl.cc>
Cc: Florian Westphal <fwestpha@redhat.com>, netfilter-devel@vger.kernel.org
Subject: Re: [nf PATCH] net: nf_tables: Make nft_meta expression more robust
Date: Thu, 18 Jul 2019 20:10:34 +0200 [thread overview]
Message-ID: <20190718181034.gwe5tu4z2j4m7zyv@salvia> (raw)
In-Reply-To: <20190718033729.12438-1-phil@nwl.cc>
On Thu, Jul 18, 2019 at 05:37:29AM +0200, Phil Sutter wrote:
> nft_meta_get_eval()'s tendency to bail out setting NFT_BREAK verdict in
> situations where required data is missing breaks inverted checks
> like e.g.:
>
> | meta iifname != eth0 accept
>
> This rule will never match if there is no input interface (or it is not
> known) which is not intuitive and, what's worse, breaks consistency of
> iptables-nft with iptables-legacy.
>
> Fix this by falling back to placing a value in dreg which never matches
> (avoiding accidental matches):
>
> {I,O}IF:
> Use invalid ifindex value zero.
>
> {I,O}IFNAME, {I,O}IFKIND:
> Use an empty string which is neither a valid interface name nor
> kind.
>
> {I,O}IFTYPE:
> Use ARPHRD_VOID (0xFFFF).
>
> Signed-off-by: Phil Sutter <phil@nwl.cc>
> ---
> net/netfilter/nft_meta.c | 45 +++++++++++++++++-----------------------
Missing update for:
net/bridge/netfilter/nft_meta_bridge.c
next prev parent reply other threads:[~2019-07-18 18:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-18 3:37 [nf PATCH] net: nf_tables: Make nft_meta expression more robust Phil Sutter
2019-07-18 18:10 ` Pablo Neira Ayuso [this message]
2019-07-18 18:12 ` Pablo Neira Ayuso
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