From 15c6f5a7a2f615ec6d510e913d7fb44d94fbafa4 Mon Sep 17 00:00:00 2001
From: Jared Hancock <jared@osticket.com>
Date: Thu, 20 Feb 2014 21:43:42 -0600
Subject: [PATCH] Predictable message-ids
Outbound message-ids are predictable, with a consistent code unique and
static to each osTicket installation. This will help detect email loops
where message is delivered back to the system in an email loop.
---
include/class.mailer.php | 4 +++-
include/class.thread.php | 13 +++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/include/class.mailer.php b/include/class.mailer.php
index 41d82e8c8..c5837f683 100644
--- a/include/class.mailer.php
+++ b/include/class.mailer.php
@@ -100,7 +100,9 @@ class Mailer {
$subject = preg_replace("/(\r\n|\r|\n)/s",'', trim($subject));
/* Message ID - generated for each outgoing email */
- $messageId = sprintf('<%s-%s>', Misc::randCode(16),
+ $messageId = sprintf('<%s-%s-%s>',
+ substr(md5('mail'.SECRET_SALT), -9),
+ Misc::randCode(9),
($this->getEmail()?$this->getEmail()->getEmail():'@osTicketMailer'));
$headers = array (
diff --git a/include/class.thread.php b/include/class.thread.php
index 35ec91788..355e0890e 100644
--- a/include/class.thread.php
+++ b/include/class.thread.php
@@ -618,6 +618,19 @@ Class ThreadEntry {
// Reporting success so the email can be moved or deleted.
return true;
+ // Mail sent by this system will have a message-id format of
+ // <code-random-mailbox@domain.tld>
+ // where code is a predictable string based on the SECRET_SALT of
+ // this osTicket installation. If this incoming mail matches the
+ // code, then it very likely originated from this system and looped
+ @list($code) = explode('-', $mailinfo['mid'], 2);
+ if (0 === strcasecmp(ltrim($code, '<'), substr(md5('mail'.SECRET_SALT), -9))) {
+ // This mail was sent by this system. It was received due to
+ // some kind of mail delivery loop. It should not be considered
+ // a response to an existing thread entry
+ return true;
+ }
+
$vars = array(
'mid' => $mailinfo['mid'],
'header' => $mailinfo['header'],
--
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