Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good.

Path	csiph.com!news.mixmin.net!aioe.org!gothmog.csi.it!bofh.it!news.nic.it!robomod
From	Ben Hutchings <ben@decadent.org.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good.
Date	Sat, 30 Apr 2016 21:30:02 +0200
Message-ID	<rtIKu-4Aw-19@gated-at.bofh.it> (permalink)
References	<rskKd-80r-11@gated-at.bofh.it> <rsA2D-3Ck-13@gated-at.bofh.it> <rsC4r-5HB-39@gated-at.bofh.it> <rsHGN-1Zc-1@gated-at.bofh.it> <rsHQu-23g-1@gated-at.bofh.it> <rsRwv-1zl-65@gated-at.bofh.it>
Content-Type	multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-MDk0dTSWxzYASKoxCrDC"
X-Mailer	Evolution 3.18.5.1-1
MIME-Version	1.0
X-Sa-Exim-Connect-IP	80.110.71.10
X-Sa-Exim-Mail-From	ben@decadent.org.uk
X-Sa-Exim-Scanned	No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	88
Organization	linux.* mail to news gateway
X-Original-Cc	Hannes Frederic Sowa <hannes@stressinduktion.org>, linux-kernel@vger.kernel.org, stable@vger.kernel.org, akpm@linux-foundation.org, "David S. Miller" <davem@davemloft.net>, Vijay Pandurangan <vijayp@vijayp.ca>, Cong Wang <cwang@twopensource.com>, netdev@vger.kernel.org, Evan Jones <ej@evanjones.ca>, Nicolas Dichtel <nicolas.dichtel@6wind.com>, Phil Sutter <phil@nwl.cc>, Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>, xiyou.wangcong@gmail.com
X-Original-Date	Sat, 30 Apr 2016 20:33:01 +0200
X-Original-Message-ID	<1462041181.17662.3.camel@decadent.org.uk>
X-Original-References	<lsq.1461711744.699003961@decadent.org.uk> <5720E1F0.9010203@candelatech.com> <1461780469.5102.0.camel@decadent.org.uk> <1461801603.3971874.591751457.2DB91B98@webmail.messagingengine.com> <572155F4.10405@candelatech.com> <20160428102953.GA7656@bistromath.localdomain>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1391660

Show key headers only | View raw

[Multipart message — attachments visible in raw view] - view raw

On Thu, 2016-04-28 at 12:29 +0200, Sabrina Dubroca wrote:
> Hello,
> 
> 2016-04-27, 17:14:44 -0700, Ben Greear wrote:
> > 
> > On 04/27/2016 05:00 PM, Hannes Frederic Sowa wrote:
> > > 
> > > Hi Ben,
> > > 
> > > On Wed, Apr 27, 2016, at 20:07, Ben Hutchings wrote:
> > > > 
> > > > On Wed, 2016-04-27 at 08:59 -0700, Ben Greear wrote:
> > > > > 
> > > > > On 04/26/2016 04:02 PM, Ben Hutchings wrote:
> > > > > > 
> > > > > > 
> > > > > > 3.2.80-rc1 review patch.  If anyone has any objections, please let me know.
> > > > > I would be careful about this.  It causes regressions when sending
> > > > > PACKET_SOCKET buffers from user-space to veth devices.
> > > > > 
> > > > > There was a proposed upstream fix for the regression, but it has not gone
> > > > > into the tree as far as I know.
> > > > > 
> > > > > http://www.spinics.net/lists/netdev/msg370436.html
> > > > [...]
> > > > 
> > > > OK, I'll drop this for now.
> > > The fall out from not having this patch is in my opinion a bigger
> > > fallout than not having this patch. This patch fixes silent data
> > > corruption vs. the problem Ben Greear is talking about, which might not
> > > be that a common usage.
> > > 
> > > What do others think?
> > > 
> > > Bye,
> > > Hannes
> > > 
> > This patch from Cong Wang seems to fix the regression for me, I think it should be added and
> > tested in the main tree, and then apply them to stable as a pair.
> > 
> > http://dmz2.candelatech.com/?p=linux-4.4.dev.y/.git;a=commitdiff;h=8153e983c0e5eba1aafe1fc296248ed2a553f1ac;hp=454b07405d694dad52e7f41af5816eed0190da8a
> Actually, no, this is not really a regression.
[...]

It really is.  Even though the old behaviour was a bug (raw packets
should not be changed), if there are real applications that depend on
that then we have to keep those applications working somehow.

Ben.

-- 
Ben Hutchings
Tomorrow will be cancelled due to lack of interest.

Thread

Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats  packets with bad checksums as good. Sabrina Dubroca <sd@queasysnail.net> - 2016-04-28 12:40 +0200
  Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Ben Greear <greearb@candelatech.com> - 2016-04-28 15:50 +0200
    Re: [PATCH 3.2 085/115] veth: don’t modify  ip_summed; doing so treats packets with bad checksums as good. Ben Hutchings <ben@decadent.org.uk> - 2016-04-30 21:30 +0200
  Re: [PATCH 3.2 085/115] veth: don’t modify  ip_summed; doing so treats packets with bad checksums as good. Ben Hutchings <ben@decadent.org.uk> - 2016-04-30 21:30 +0200
    Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Ben Greear <greearb@candelatech.com> - 2016-04-30 21:50 +0200
      Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Tom Herbert <tom@herbertland.com> - 2016-04-30 22:00 +0200
        Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Ben Greear <greearb@candelatech.com> - 2016-04-30 23:00 +0200
          Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Vijay Pandurangan <vijayp@vijayp.ca> - 2016-04-30 23:20 +0200
            Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Ben Greear <greearb@candelatech.com> - 2016-04-30 23:40 +0200
              Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Vijay Pandurangan <vijayp@vijayp.ca> - 2016-04-30 23:40 +0200
                Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Ben Greear <greearb@candelatech.com> - 2016-05-01 00:00 +0200
                Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Vijay Pandurangan <vijayp@vijayp.ca> - 2016-05-01 00:10 +0200
                Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Ben Greear <greearb@candelatech.com> - 2016-05-01 00:50 +0200
                Re: [PATCH 3.2 085/115] veth: don???t modify ip_summed; doing so  treats packets with bad checksums as good. Willy Tarreau <w@1wt.eu> - 2016-05-01 07:40 +0200
          Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Tom Herbert <tom@herbertland.com> - 2016-05-01 00:50 +0200
  Re: [PATCH 3.2 085/115] veth: don’t modify ip_summed; doing so treats packets with bad checksums as good. Vijay Pandurangan <vijayp@vijayp.ca> - 2016-04-30 22:20 +0200

csiph-web