netdev - Re: [PATCH net v2 1/1] net/sched: act_ct: Fix flow table lookup failure with no originating ifindex

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <c615b6c2-6a84-7348-2bd8-447e28cbb8b@nvidia.com>
Date:   Mon, 21 Feb 2022 19:02:45 +0200
From:   Paul Blakey <paulb@...dia.com>
To:     Pablo Neira Ayuso <pablo@...filter.org>
CC:     <dev@...nvswitch.org>, <netdev@...r.kernel.org>,
        Jamal Hadi Salim <jhs@...atatu.com>, <davem@...emloft.net>,
        Jiri Pirko <jiri@...dia.com>,
        "Cong Wang" <xiyou.wangcong@...il.com>,
        Jakub Kicinski <kuba@...nel.org>,
        <netfilter-devel@...r.kernel.org>,
        Jozsef Kadlecsik <kadlec@...filter.org>,
        Oz Shlomo <ozsh@...dia.com>, Vlad Buslov <vladbu@...dia.com>,
        Roi Dayan <roid@...dia.com>,
        Ariel Levkovich <lariel@...dia.com>, <coreteam@...filter.org>
Subject: Re: [PATCH net v2 1/1] net/sched: act_ct: Fix flow table lookup
 failure with no originating ifindex




On Sun, 20 Feb 2022, Pablo Neira Ayuso wrote:

> Hi Paul,
> 
> On Sun, Feb 20, 2022 at 11:32:26AM +0200, Paul Blakey wrote:
> > After cited commit optimizted hw insertion, flow table entries are
> > populated with ifindex information which was intended to only be used
> > for HW offload. This tuple ifindex is hashed in the flow table key, so
> > it must be filled for lookup to be successful. But tuple ifindex is only
> > relevant for the netfilter flowtables (nft), so it's not filled in
> > act_ct flow table lookup, resulting in lookup failure, and no SW
> > offload and no offload teardown for TCP connection FIN/RST packets.
> > 
> > To fix this, remove ifindex from hash, and allow lookup without
> > the ifindex. Act ct will lookup without the ifindex filled.
> 
> I think it is good to add FLOW_OFFLOAD_XMIT_TC (instead of relying on
> FLOW_OFFLOAD_XMIT_UNSPEC), this allows for more tc specific fields in
> the future.
> 
> See attached patch.
> 
> Thanks.
> 

This patch will fix it, but ifindex which we fill is for the input device 
and not related to XMIT, exactly what tuple->iifidx means. We don't have 
XMIT, so I think it was ok to use  UNSPEC for now. If I use 
tuple->tc.iifidx as you suggest, tuple->iifidx  will remain unused.

I think once we have more fields that are really specific to TC, we 
can do what you sugguest, right now we can share the ifindex.