netdev - Re: [PATCH stable 4.4 0/9] fix SegmentSmack (CVE-2018-5390)

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Date:   Thu, 16 Aug 2018 09:20:41 +0800
From:   maowenan <maowenan@...wei.com>
To:     Greg KH <gregkh@...ux-foundation.org>
CC:     <dwmw2@...radead.org>, <netdev@...r.kernel.org>,
        <eric.dumazet@...il.com>, <edumazet@...gle.com>,
        <davem@...emloft.net>, <ycheng@...gle.com>, <jdw@...zon.de>
Subject: Re: [PATCH stable 4.4 0/9] fix SegmentSmack (CVE-2018-5390)



On 2018/8/15 23:41, Greg KH wrote:
> On Wed, Aug 15, 2018 at 03:24:32PM +0200, Greg KH wrote:
>> On Wed, Aug 15, 2018 at 09:20:59PM +0800, Mao Wenan wrote:
>>> There are five patches to fix CVE-2018-5390 in latest mainline 
>>> branch, but only two patches exist in stable 4.4 and 3.18: 
>>> dc6ae4d tcp: detect malicious patterns in tcp_collapse_ofo_queue()
>>> 5fbec48 tcp: avoid collapses in tcp_prune_queue() if possible
>>> but I have tested with these patches, and found the cpu usage was very high.
>>> test results:
>>> with fix patch： 78.2%   ksoftirqd
>>> no fix patch：   90%     ksoftirqd
>>>
>>> After analysing the codes of stable 4.4, and debuging the 
>>> system, the search of ofo_queue(tcp ofo using a simple queue) cost more cycles.
>>> So I think only two patches can't fix the CVE-2018-5390.
>>> So I try to backport "tcp: use an RB tree for ooo receive queue" using RB tree 
>>> instead of simple queue, then backport Eric Dumazet 5 fixed patches in mainline,
>>> good news is that ksoftirqd is turn to about 20%, which is the same with mainline now.
>>
>> Thanks for doing this work, I had some questions on the individual
>> patches.  Can you address them and resend?
> 
> Also, always cc: the stable@...r list when sending stable patches so
> that others can review and comment on them.

ok,I will resend patches later after refining them.

> 
> thanks,
> 
> greg k-h
> 
> .
>