Re: send-email garbled header with trailing doublequote in email

From: Jeff King <peff@peff.net>
Date: Nov 3, 2016, 14:18 UTC
Message-ID: <20161103141848.42pg6iow24prign5@sigill.intra.peff.net>
In-Reply-To: <20161102222901.GK4611@redhat.com>

On Wed, Nov 02, 2016 at 11:29:01PM +0100, Andrea Arcangeli wrote:

Show 7 quoted lines

> So this must be postfix then that out of the blue decided to garble it
> in a strange way while parsing the input... The removal of all
> whitespaces s/what ever/whatever/ especially I've no idea how it
> decided to do so.
> 
> Can you reproduce with postfix as sendmail at least? If you can
> reproduce also see what happens if you add another --to.

Yes, I can easily reproduce without using git at all by installing postfix in local-delivery mode and running:

sendmail peff@sigill.intra.peff.net <<\EOF
From: Jeff King <peff@peff.net>
To: "what ever" " <peff@sigill.intra.peff.net>
Subject: patch

This is the body EOF

Many MTAs do this kind of header-rewriting. I don't necessarily agree with it as a general concept, but the real problem is the syntactically bogus header. The munging that postfix does makes things worse, but I can see why it is confused and does what it does (the whole email is inside a double-quoted portion that is never closed, so it probably thinks there is no hostname portion at all).

So git is possibly at fault for passing along a bogus address. OTOH, the user is perhaps at fault for providing the bogus address to git in the first place. GIGO. :)

I think if any change were to be made, it would be to recognize this bogosity and either clean it up or abort. That ideally would happen via Mail::Address so git does not have to add a bunch of ad-hoc "is this valid rfc822" checks. Reading the manpage for that module, though, it says:

  [we do not handle all of rfc2822]
  Often requests are made to the maintainers of this code improve this
  situation, but this is not a good idea, where it will break zillions
  of existing applications.  If you wish for a fully RFC2822 compliant
  implementation you may take a look at Mail::Message::Field::Full, part
  of MailBox.

So it's possible that switching to a more robust module would improve things.

-Peff