Date:   Thu, 9 Feb 2023 17:09:58 +0100 (CET)
From:   Jan Engelhardt <jengelh@inai.de>
To:     Florian Westphal <fw@strlen.de>
cc:     Igor Artemiev <Igor.A.Artemiev@mcst.ru>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Jozsef Kadlecsik <kadlec@netfilter.org>,
        netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        lvc-project@linuxtesting.org
Subject: Re: [lvc-project] [PATCH] netfilter: xt_recent: Fix attempt to update
 removed entry
In-Reply-To: <20230209150733.GA17303@breakpoint.cc>
Message-ID: <6152n4q7-1ssr-521p-786s-71q4q9731370@vanv.qr>
References: <20230209125831.2674811-1-Igor.A.Artemiev@mcst.ru> <20230209150733.GA17303@breakpoint.cc>
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On Thursday 2023-02-09 16:07, Florian Westphal wrote:

>Igor Artemiev <Igor.A.Artemiev@mcst.ru> wrote:
>> When both --remove and --update flag are specified, there's a code
>> path at which the entry to be updated is removed beforehand,
>> that leads to kernel crash. Update entry, if --remove flag
>> don't specified.
>> 
>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
>How did you manage to do this?  --update and --remove are supposed
>to be mutually exclusive.

I suppose the exclusivity is only checked at the iptables command-line
and neverwhere else.