netdev - Re: [PATCH ipsec,v2] xfrm: fix "disable

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Date:   Mon, 10 Oct 2022 14:19:36 +0200
From:   Nicolas Dichtel <nicolas.dichtel@...nd.com>
To:     Eyal Birger <eyal.birger@...il.com>
Cc:     steffen.klassert@...unet.com, davem@...emloft.net,
        yoshfuji@...ux-ipv6.org, dsahern@...nel.org, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, netdev@...r.kernel.org,
        monil191989@...il.com, stephen@...workplumber.org
Subject: Re: [PATCH ipsec,v2] xfrm: fix "disable_policy" on ipv4 early demux

Le 10/10/2022 à 12:29, Eyal Birger a écrit :
> Hi Nicolas,
> 
> On Mon, Oct 10, 2022 at 11:28 AM Nicolas Dichtel
> <nicolas.dichtel@...nd.com> wrote:
>>
>> Le 09/10/2022 à 21:16, Eyal Birger a écrit :
>>> The commit in the "Fixes" tag tried to avoid a case where policy check
>>> is ignored due to dst caching in next hops.
>>>
>>> However, when the traffic is locally consumed, the dst may be cached
>>> in a local TCP or UDP socket as part of early demux. In this case the
>>> "disable_policy" flag is not checked as ip_route_input_noref() was only
>>> called before caching, and thus, packets after the initial packet in a
>>> flow will be dropped if not matching policies.
>>>
>>> Fix by checking the "disable_policy" flag also when a valid dst is
>>> already available.
>>>
>>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216557
>>> Reported-by: Monil Patel <monil191989@...il.com>
>>> Fixes: e6175a2ed1f1 ("xfrm: fix "disable_policy" flag use when arriving from different devices")
>>> Signed-off-by: Eyal Birger <eyal.birger@...il.com>
>>>
>>
>> Is there the same problem with ipv6?
> 
> The issue is specific to IPv4 as the original fix was only relevant
> to IPv4.
> 
> I also tested a similar scenario using IPv6 addresses and did not see
> a problem.
Thanks. Is it possible to write a selftest with this scenario?


Regards,
Nicolas