netdev - Re: [PATCH bpf v2 1/5] bpf, sockmap: Use stricter sk state checks in sk_lookup

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Message-ID: <87wnljgdpc.fsf@cloudflare.com>
Date:   Mon, 08 Nov 2021 11:10:39 +0100
From:   Jakub Sitnicki <jakub@...udflare.com>
To:     John Fastabend <john.fastabend@...il.com>
Cc:     bpf@...r.kernel.org, netdev@...r.kernel.org, daniel@...earbox.net,
        joamaki@...il.com, xiyou.wangcong@...il.com
Subject: Re: [PATCH bpf v2 1/5] bpf, sockmap: Use stricter sk state checks
 in sk_lookup_assign

On Wed, Nov 03, 2021 at 09:47 PM CET, John Fastabend wrote:
> In order to fix an issue with sockets in TCP sockmap redirect cases
> we plan to allow CLOSE state sockets to exist in the sockmap. However,
> the check in bpf_sk_lookup_assign currently only invalidates sockets
> in the TCP_ESTABLISHED case relying on the checks on sockmap insert
> to ensure we never SOCK_CLOSE state sockets in the map.
>
> To prepare for this change we flip the logic in bpf_sk_lookup_assign()
> to explicitly test for the accepted cases. Namely, a tcp socket in
> TCP_LISTEN or a udp socket in TCP_CLOSE state. This also makes the
> code more resilent to future changes.
>
> Suggested-by: Jakub Sitnicki <jakub@...udflare.com>
> Signed-off-by: John Fastabend <john.fastabend@...il.com>
> ---

Thanks, John, for patching up the helper.

I will follow up with a test to cover unbound sockets.

Reviewed-by: Jakub Sitnicki <jakub@...udflare.com>