Re: Emails from kvack.org going into spam

[Benjamin LaHaise <bcrl@kvack.org>]

On Fri, Oct 16, 2020 at 02:57:33PM +0100, Matthew Wilcox wrote:
> On Fri, Oct 16, 2020 at 10:54:51AM -0300, Jason Gunthorpe wrote:
> > Does anyone know who is the admin for kvack.org?
> 
> That's Ben.  Adding cc.

Without suggestions for how to fix the issue, there's not much I can do.
majordomo doesn't modify the message body - that was changed years ago to
deal with the first round of DKIM breakage.  Postfix must be mangling
things, but I have no idea how to prevent that.  I wish people wouldn't
keep coming up with new ways to break mailing lists.

		-ben


> > I was cleaning my GMail spam mail box and saw lots of messages from
> > Jann Horn in the spam filter. Since he is not a spammer I investigated
> > what is going on.
> > 
> > I see it is because GMail is flagging all of Jann's messages as having
> > a DKIM failure and Jann's employeer domain 'google.com' is enforcing a
> > DMARC policy:
> > 
> > Authentication-Results: mx.google.com;
> >        dkim=neutral (body hash did not verify) header.i=@google.com header.s=20161025 header.b=UzPVodG7;
> >        spf=pass (google.com: domain of owner-linux-mm@kvack.org designates 205.233.56.17 as permitted sender) smtp.mailfrom=owner-linux-mm@kvack.org;
> >        dmarc=fail (p=REJECT sp=REJECT dis=QUARANTINE) header.from=google.com
> > 
> > Selecting a message from Jann that went through LKML and kvack:
> > 
> >   https://lore.kernel.org/lkml/20201015000041.1734214-1-jannh@google.com/raw
> >   https://lore.kernel.org/linux-mm/20201015000041.1734214-1-jannh@google.com/raw
> > 
> > And checking the DKIM:
> > 
> >   $ opendkim-testmsg < raw.lkml
> >   $ opendkim-testmsg < raw.mm
> >   opendkim-testmsg: dkim_eom(): Bad signature
> > 
> > Confirms that Jann sent the message correctly, but kvack is breaking
> > the signature while vger is not. The DMARC policy on Jann's email is
> > causing receivers to junk his email as spam. I expect I'm not the only
> > one.
> > 
> > I see that kvack is modifying the message in transit. Notably it
> > changed the transfer encoding from
> >  Content-Transfer-Encoding: 8bit
> > to
> >  Content-Transfer-Encoding: quoted-printable
> > 
> > And mangled the body accordingly. Changing the
> > Content-Transfer-Encoding definitely breaks the signature.
> > 
> > This seems to be a fairly big problem - it is extra hard for people to
> > contribute. Setting up a text based email flow is already hard, but
> > having to also somehow obtain an email address that doesn't use DMARC
> > is becoming an increasingly tough bar to clear.
> > 
> > eg what will people even do if/when Google decides to enable DMARC on
> > gmail.com as well?
> > 
> > Is it possible that this list software can be reconfigured to match
> > the vger lists that do seem to work OK?
> > 
> > Is moving the list to vger an option?
> > 
> > Thanks,
> > Jason
> > 
> 

-- 
"Thought is the essence of where you are now."