[Users] encoded addresses causing problems in reply

[Milan Obuch]

On Wed, 7 Sep 2022 12:17:37 -0700
"Derek B. Noonburg" <derekn at foolabs.com> wrote:

> If I do a reply-all to an email with ISO-2022-JP encoded addresses,
> the to/cc headers in the resulting message end up mangled.
> 
> I'm not sure exactly where this is happening -- it may or may not have
> anything to do with claws -- but I'm hoping to get some advice on how
> to debug the problem.
> 
> I unfortunately can't forward the email, because it's from a customer.
> I understand this makes it harder to debug, but I'm hoping maybe
> someone has encountered something similar, or has some other helpful
> suggestions anyway.

I did an analysis of some mail header problem recently, in my case, it
was in no relation to Claws Mail. As you can't forward the offending
mail, it would be nice to find some way to replicate the issue.

> Looking at the original email (to which I'm replying) with "view
> source", the from/cc headers look like this:
> 
> From: =?iso-2022-jp?B?xxxxxxxx==?=
> 	<aaaa at example.com>
> CC: =?iso-2022-jp?B?xxxxxxxx?=
> 	<bbbb at example.com>,
> 	=?iso-2022-jp?B?xxxxxxx==?=
> 	<cccc at example.com>
> 	=?iso-2022-jp?B?xxxxxxx==?=

When looking to source, I'd be interested in X-Mailer of similar header
if any. If it's not there, maybe you can ask your customer which MUA is
used. If your issue is address encoding problem, and what your
description suggests, exact address is not that important, it's presence
of base64 encoded Japanese name.

If anybody 
> When I hit reply-all, the headers in the claws compose window look
> perfect.  (I don't read Japanese, but as far as I can tell, everything
> looks good.)  I'm seeing:
> 
> To: JJJ / xxxx, xxxx <aaaa at example.com>
> Cc: JJJ / xxxx, xxxx <bbbb at example.com>
> Cc: JJJ / xxxx, xxxx <cccc at example.com>
> 
> where "J" are Japanese characters.
> 
> One suspicious thing here is that there are spaces, slashes, and
> commas, and no quoting.  But I'm not sure what the rules are for
> encoding email addresses (the "=?iso-222-jp...." stuff).  In the
> original email headers, the spaces and punctuation are "inside" the 
> encoded blobs.

I did some simple experiments in Claws Mail - if I put a comma into
Name field of my account, there is quoting in From header. If there is
no comma, just space and/or slash, no quoting. I have no exact
knowledge on encoding rules, this is just an observation, how Claws
Mail handles some cases.

> If I bcc the reply to myself and view source on that, the headers are
> mangled pretty badly:
> 
> To: =?iso-2022-jp?Q?=1B$B at foolabs.com>,
> 	#0f6Q=1B at foolabs.com (B?= / =?iso-2022-jp?Q?xxxxx?=
>  =?iso-2022-jp?Q?xxxx?= <aaaa at example.com>
> Cc: "=?iso-2022-jp?Q?=xxxx"@foolabs.com;, <R=1B at foolabs.com>
> 
> where "foolabs.com" is my sending domain.  The one original "to"
> address (aaaa at example.com) shows up correctly amidst the gibberish,
> but everything else is gone.

Did this mail go through your mail server? If so, this may be caused by
some rewrite rules in server. Commonly used one is adding domain to
local part assuming it is a name only. If you are sending this mail
from Claws Mail, you should have saved copy in Sent folder (or another
folder if you configure it so). It would be interesting to see whether
there is any difference in headers in you locally saved mail (before
sending to server) and mail processed by server (delivered to bcc
address).

> I can't really send a bunch of email to the customer to test this, and
> I can't forward email due to confidentiality (I know this makes
> debugging difficult) -- but if anyone has suggestions for how I can
> debug this, I'd really appreciate it.

I remember we did someone on this mailing list using Japanese characters
in his mails, I don't know whether he is still active. Mybe he can help
more...

As I am writing this, I realized in past I had problems with subjects
containing some accented letters. In body of the message the problem
did not appear. After some experiments with various setting I found
simple solution - setting LANG environment variable to C.UTF-8
(standard value was C.ASCII I think). I am using FreeBSD, so this could
be different for you, but it is simple to check and try, eventually.

Regards,
Milan