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

[Greg KH <gregkh@linux-foundation.org>]

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@vger list when sending stable patches so
that others can review and comment on them.

thanks,

greg k-h