From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net] tcp: fix 0 divide in __tcp_select_window()
Date: Wed, 01 Feb 2017 12:56:08 -0500 (EST)
Message-ID: <20170201.125608.445685471651002821.davem@davemloft.net>
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Cc: netdev@vger.kernel.org, dvyukov@google.com
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 01 Feb 2017 08:33:53 -0800

> From: Eric Dumazet <edumazet@google.com>
> 
> syszkaller fuzzer was able to trigger a divide by zero, when
> TCP window scaling is not enabled.
> 
> SO_RCVBUF can be used not only to increase sk_rcvbuf, also
> to decrease it below current receive buffers utilization.
> 
> If mss is negative or 0, just return a zero TCP window.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Dmitry Vyukov  <dvyukov@google.com>
> ---
> No Fixes: tag, this is a day-0 bug.

Applied and queued up for -stable, thanks Eric.