From: Jesper Dangaard Brouer <brouer@redhat.com>
To: ebiederm@xmission.com (Eric W. Biederman)
Cc: brouer@redhat.com, Cong Wang <xiyou.wangcong@gmail.com>,
David Miller <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
Patrick McHardy <kaber@trash.net>,
Stephen Hemminger <stephen@networkplumber.org>,
Cong Wang <cwang@twopensource.com>,
Stefan Bader <stefan.bader@canonical.com>,
stephane.graber@canonical.com, chris.j.arges@canonical.com,
Serge Hallyn <serge.hallyn@canonical.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>
Subject: Re: [Patch net-next] net: make neigh tables per netns
Date: Mon, 30 Jun 2014 20:15:18 +0200 [thread overview]
Message-ID: <20140630201518.653ebbaf@redhat.com> (raw)
In-Reply-To: <87vbrl8vmz.fsf@x220.int.ebiederm.org>
On Fri, 27 Jun 2014 22:12:52 -0700 ebiederm@xmission.com (Eric W. Biederman) wrote:
> Cong Wang <xiyou.wangcong@gmail.com> writes:
> > On Thu, Jun 26, 2014 at 3:44 PM, David Miller <davem@davemloft.net> wrote:
> >>
[...]
> >
> > Hmm, I did overlook the potential DOS problem. But hold on, isn't
> > IP fragments have the same problem? The fragment queues are per
> > netns, and the thresh is per netns as well, we will eventually have
> > memory pressure as well.
>
> Interesting. It does look like ip fragments are susceptible that way.
For IP fragments we have per netns mem-limit and LRU-list, but all
netns share the same hash table, which have its own DoS potential.
And argh! - we have a hardcoded INETFRAGS_MAXDEPTH=128, which can be
used for (slow) DoS of IP frags if enough netns are created.
https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/tree/net/ipv4/inet_fragment.c#n344
Introduced by commit 5a3da1fe9 ("inet: limit length of fragment queue
hash table bucket lists").
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Sr. Network Kernel Developer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2014-06-30 18:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-23 22:09 [Patch net-next] net: make neigh tables per netns Cong Wang
2014-06-25 23:33 ` David Miller
2014-06-26 0:04 ` Eric W. Biederman
2014-06-26 0:22 ` Cong Wang
2014-06-26 1:17 ` Eric W. Biederman
2014-06-26 6:14 ` Michal Kubecek
2014-06-26 12:10 ` Eric W. Biederman
2014-06-26 20:43 ` David Miller
[not found] ` <87egybibh5.fsf@x220.int.ebiederm.org>
2014-06-26 22:44 ` David Miller
2014-06-28 0:09 ` Cong Wang
2014-06-28 5:12 ` Eric W. Biederman
2014-06-30 18:15 ` Jesper Dangaard Brouer [this message]
2014-06-30 18:54 ` Hannes Frederic Sowa
2014-11-04 15:49 ` Stéphane Graber
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