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

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Date:   Mon, 10 Oct 2022 13:29:15 +0300
From:   Eyal Birger <eyal.birger@...il.com>
To:     nicolas.dichtel@...nd.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

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!
Eyal.