Garbled mails in Maildir storage

Hi, from time to time i am having mails delivered to my anon maildrop which completely break mailbox listing.

I ignored it mostly as this is an anon maildrop for one time emails so loosing spam wasnt an issue. Today i had a mailbox which wouldnt list at all which was caused by 50 consecutive mails beeing broken. (I am showing the last 20 in the web interface)

After some debugging i found a bunch of mails like this:

Return-Path: <*************************>
X-Original-To: test@wasteland.rfc822.org
Delivered-To: inbox@wasteland.rfc822.org
Received: from node11.tmdvps.com (unknown [184.154.211.109])
	by pax.zz.de (Postfix) with SMTP id 3B73DD00B5
	for <test@wasteland.rfc822.org>; Thu,  8 Jun 2017 17:09:25 +0200 (CEST)

<U+FEFF>Date: Thu, 8 Jun 2017 10:09:24 +0000 (GMT)
From: Apple Support <*************************>
REPLY-TO: do_not_reply@apple.com
To: test@wasteland.rfc822.org
[ ... ]

Yes - there is an UTF-8 BOM in the middle of the mail header. Breaks parsing of the mail header of dovecot. No From and To in the listing.

And i found even more:

Return-Path: <**********************>
X-Original-To: test@wasteland.rfc822.org
Delivered-To: inbox@wasteland.rfc822.org
Received: from 36.248.164.233 (unknown [36.248.164.233])
	by pax.zz.de (Postfix) with SMTP id B2B0F1000FF;
	Tue, 22 Jan 2019 10:37:35 +0100 (CET)
Received: from 6.51.138.64 by ; Tue, 22 Jan 2019 04:36:35 -0500
Message-ID: <B[20

Mails that end with garbage in them middle of the mail header. This is a standard Maildir storage using the dovecot transport via postfix.

Does anyone have an explanation for these kind of mailstorage breakage? How could broken mails like this even be processed by postfix, dovecot deliver etc.

As the last mail is pretty current i quickly grepped the postfix logs:

Jan 22 10:37:35 pax postfix/smtpd[20269]: B2B0F1000FF: client=unknown[36.248.164.233] Jan 22 10:37:37 pax postfix/cleanup[20371]: B2B0F1000FF: message-id=, size=233, nrcpt=2 (queue active) Jan 22 10:37:37 pax postfix/pipe[19192]: B2B0F1000FF: to=inbox@wasteland.rfc822.org, orig_to=test108@wasteland.rfc822.org, relay=wasteland, delay=2.2, delays=1.7/0/0/0.41, dsn=2.0.0, status=sent (delivered via wasteland service) Jan 22 10:37:37 pax postfix/pipe[21064]: B2B0F1000FF: to=inbox@wasteland.rfc822.org, orig_to=test@wasteland.rfc822.org, relay=wasteland, delay=2.2, delays=1.7/0.01/0/0.48, dsn=2.0.0, status=sent (delivered via wasteland service) Jan 22 10:37:37 pax postfix/qmgr[9371]: B2B0F1000FF: removed

So even postfix found the message id to be truncated.

Does dovecot have a "broken maildir mail storage mail dictionary" for automated tests?

Flo

Florian Lohoff f@zz.de UTF-8 Test: The 🐈 ran after a 🐁, but the 🐁 ran away