netdev - Re: [PATCH nf] netfilter: restore default behavior for nf_conntrack

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Message-ID: <523daa3d-83b0-495a-bf6e-3b8fd661cffd@6wind.com>
Date: Wed, 3 Jul 2024 09:37:59 +0200
From: Nicolas Dichtel <nicolas.dichtel@...nd.com>
To: Pablo Neira Ayuso <pablo@...filter.org>
Cc: Florian Westphal <fw@...len.de>, netdev@...r.kernel.org,
 netfilter-devel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH nf] netfilter: restore default behavior for
 nf_conntrack_events

Hi Pablo,

Le 26/06/2024 à 13:41, Pablo Neira Ayuso a écrit :
> Hi Nicolas,
> 
> On Tue, Jun 04, 2024 at 03:54:38PM +0200, Nicolas Dichtel wrote:
>> Since the below commit, there are regressions for legacy setups:
>> 1/ conntracks are created while there are no listener
>> 2/ a listener starts and dumps all conntracks to get the current state
>> 3/ conntracks deleted before the listener has started are not advertised
>>
>> This is problematic in containers, where conntracks could be created early.
>> This sysctl is part of unsafe sysctl and could not be changed easily in
>> some environments.
>>
>> Let's switch back to the legacy behavior.
> 
> Maybe it is possible to annotate destroy events in a percpu area if
> the conntrack extension is not available. This code used to follow
> such approach time ago.
Thanks for the feedback. I was wondering if just sending the destroy event would
be possible. TBH, I'm not very familiar with this part of the code, I need to
dig a bit. I won't have time for this right now, any help would be appreciated.