netdev - Re: [PATCH net 2/4] tcp: tcp_fragment() should apply sane memory limits

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Message-ID: <b83b7aa4-9b0d-f9ad-6148-03e9828392c8@gmail.com>
Date:   Thu, 11 Jul 2019 12:18:46 +0200
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Christoph Paasch <christoph.paasch@...il.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Cc:     "Prout, Andrew - LLSC - MITLL" <aprout@...mit.edu>,
        David Miller <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jonathan Looney <jtl@...flix.com>,
        Neal Cardwell <ncardwell@...gle.com>,
        Tyler Hicks <tyhicks@...onical.com>,
        Yuchung Cheng <ycheng@...gle.com>,
        Bruce Curtis <brucec@...flix.com>,
        Jonathan Lemon <jonathan.lemon@...il.com>,
        Dustin Marquess <dmarquess@...le.com>
Subject: Re: [PATCH net 2/4] tcp: tcp_fragment() should apply sane memory
 limits



On 7/11/19 9:28 AM, Christoph Paasch wrote:
> 

> Would it make sense to always allow the alloc in tcp_fragment when coming from __tcp_retransmit_skb() through the retransmit-timer ?
> 
> AFAICS, the crasher was when an attacker sends "fake" SACK-blocks. Thus, we would still be protected from too much fragmentation, but at least would always allow the retransmission to go out.
> 
> 
I guess this could be done and hopefully something that can be backported without too much pain,
but I am sure some people will complain because reverting to timeouts might still
show regressions :/