Possible patch-backport problem for libphp-phpmailer (DLA-1591-1)

[Salvatore Bonaccorso <carnil@debian.org>]

Hi

While preparing an update for libphp-phpmailer I noticed in the
patch/diff for DLA-1591-1 for libphp-phpmailer the following:

+--- libphp-phpmailer-5.2.9+dfsg.orig/class.phpmailer.php
++++ libphp-phpmailer-5.2.9+dfsg/class.phpmailer.php
+@@ -1022,10 +1022,12 @@ class PHPMailer
+ 
+             // Sign with DKIM if enabled
+             if (!empty($this->DKIM_domain)
+-                && !empty($this->DKIM_private)
+-                && !empty($this->DKIM_selector)
+-                && !empty($this->DKIM_domain)
+-                && file_exists($this->DKIM_private)) {
++                and !empty($this->DKIM_selector)
++                and (!empty($this->DKIM_private_string)
++                    or (!empty($this->DKIM_private)
++                        and self::isPermittedPath($this->DKIM_private)
++                        and file_exists($this->DKIM_private)
++                    ))) {
+                 $header_dkim = $this->DKIM_Add(
+                     $this->MIMEHeader . $this->mailHeader,
+                     $this->encodeHeader($this->secureHeader($this->Subject)),

The diff seem to add here just what was in the commit, and newly using
$this->DKIM_private_string . This is not used anywhere in the code in 5.2.9 as
it was added later, though.

That said, I have not followed the code further if it might raise a
real problem.

Regards,
Salvatore