netdev - Re: [PATCH net-next] tcp: better validation of received ack sequences

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Message-ID: <1495731051.6465.100.camel@edumazet-glaptop3.roam.corp.google.com>
Date:   Thu, 25 May 2017 09:50:51 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     p.fiterau-brostean@...ence.ru.nl, netdev@...r.kernel.org,
        F.Vaandrager@...ru.nl, ncardwell@...gle.com, ycheng@...gle.com,
        soheil@...gle.com
Subject: Re: [PATCH net-next] tcp: better validation of received ack
 sequences

On Thu, 2017-05-25 at 12:48 -0400, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@...il.com>
> Date: Tue, 23 May 2017 15:24:46 -0700
> 
> > Add a FLAG_NO_CHALLENGE_ACK so that tcp_rcv_state_process()
> > can choose to send a challenge ACK and discard the packet instead
> > of wrongly change socket state.
> 
> Applied, but the tests end up being double-negatives so it might
> have been easier to understand if the flag was a positive rather
> than a negative value.

I thought of this (and was in fact one of the patch I sent for internal
review at Google), but this was changing all tcp_ack() calls instead of
a single one ?

Or maybe I am missing some easier way ?

Thanks