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From:   Eric Dumazet <edumazet@google.com>
Date:   Mon, 25 Sep 2023 06:35:58 +0200
Message-ID: <CANn89iJgeCvJbcapir8WkJv6nYop5CcfxgBrx3BoxEuwp0WA_w@mail.gmail.com>
Subject: Re: [PATCH net] ipv6: tcp: add a missing nf_reset_ct() in 3WHS handling
To:     Ilya Maximets <i.maximets@ovn.org>
Cc:     netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org,
        David Ahern <dsahern@kernel.org>,
        Florian Westphal <fw@strlen.de>,
        Madhu Koriginja <madhu.koriginja@nxp.com>,
        Frode Nordahl <frode.nordahl@canonical.com>,
        Steffen Klassert <steffen.klassert@secunet.com>
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On Fri, Sep 22, 2023 at 11:04=E2=80=AFPM Ilya Maximets <i.maximets@ovn.org>=
 wrote:
>
> Commit b0e214d21203 ("netfilter: keep conntrack reference until
> IPsecv6 policy checks are done") is a direct copy of the old
> commit b59c270104f0 ("[NETFILTER]: Keep conntrack reference until
> IPsec policy checks are done") but for IPv6.  However, it also
> copies a bug that this old commit had.  That is: when the third
> packet of 3WHS connection establishment contains payload, it is
> added into socket receive queue without the XFRM check and the
> drop of connection tracking context.
>
> That leads to nf_conntrack module being impossible to unload as
> it waits for all the conntrack references to be dropped while
> the packet release is deferred in per-cpu cache indefinitely, if
> not consumed by the application.
>
> The issue for IPv4 was fixed in commit 6f0012e35160 ("tcp: add a
> missing nf_reset_ct() in 3WHS handling") by adding a missing XFRM
> check and correctly dropping the conntrack context.  However, the
> issue was introduced to IPv6 code afterwards.  Fixing it the
> same way for IPv6 now.
>
> Fixes: b0e214d21203 ("netfilter: keep conntrack reference until IPsecv6 p=
olicy checks are done")
> Link: https://lore.kernel.org/netdev/d589a999-d4dd-2768-b2d5-89dec64a4a42=
@ovn.org/
> Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
> ---

Nica catch, thanks a lot.

Reviewed-by: Eric Dumazet <edumazet@google.com>