Fix: #1238 - add support for DKIM mail signatures

3 files changed, 54 insertions, 11 deletions

diff --git a/app/Http/Controllers/AdminSiteController.php b/app/Http/Controllers/AdminSiteController.php
index b75e5ca37c..a0e7609f8b 100644
--- a/app/Http/Controllers/AdminSiteController.php
+++ b/app/Http/Controllers/AdminSiteController.php
@@ -396,6 +396,10 @@ class AdminSiteController extends AbstractBaseController
         Site::setPreference('SMTP_AUTH_USER', $params['SMTP_AUTH_USER']);
         Site::setPreference('SMTP_SSL', $params['SMTP_SSL']);
         Site::setPreference('SMTP_HELO', $params['SMTP_HELO']);
+        Site::setPreference('DKIM_DOMAIN', $params['DKIM_DOMAIN']);
+        Site::setPreference('DKIM_SELECTOR', $params['DKIM_SELECTOR']);
+        Site::setPreference('DKIM_KEY', $params['DKIM_KEY']);
+
         if ($params['SMTP_AUTH_PASS'] !== '') {
             Site::setPreference('SMTP_AUTH_PASS', $params['SMTP_AUTH_PASS']);
         }
diff --git a/app/Services/MailService.php b/app/Services/MailService.php
index 37f4e6d135..a3a74821bf 100644
--- a/app/Services/MailService.php
+++ b/app/Services/MailService.php
@@ -25,6 +25,7 @@ use Swift_Mailer;
 use Swift_Message;
 use Swift_NullTransport;
 use Swift_SendmailTransport;
+use Swift_Signers_DKIMSigner;
 use Swift_SmtpTransport;
 use Swift_Transport;
 use function str_replace;
@@ -59,10 +60,26 @@ class MailService
                 ->setFrom($from->email(), $from->realName())
                 ->setTo($to->email(), $to->realName())
                 ->setReplyTo($reply_to->email(), $reply_to->realName())
-                ->setBody($message_html, 'text/html')
-                ->addPart($message_text, 'text/plain');
+                ->setBody($message_html, 'text/html');
+
+            $dkim_domain   = Site::getPreference('DKIM_DOMAIN');
+            $dkim_selector = Site::getPreference('DKIM_SELECTOR');
+            $dkim_key      = Site::getPreference('DKIM_KEY');
+
+            if ($dkim_domain !== '' && $dkim_selector !== '' && $dkim_key !== '') {
+                $signer = new Swift_Signers_DKIMSigner($dkim_key, $dkim_domain, $dkim_selector);
+                $signer
+                    ->setHeaderCanon('relaxed')
+                    ->setBodyCanon('relaxed');
+
+                $message->attachSigner($signer);
+            } else {
+                // DKIM body hashes don't work with multipart/alternative content.
+                $message->addPart($message_text, 'text/plain');
+            }
 
             $mailer = new Swift_Mailer($this->transport());
+
             $mailer->send($message);
         } catch (Exception $ex) {
             Log::addErrorLog('MailService: ' . $ex->getMessage());
diff --git a/resources/views/admin/site-mail.phtml b/resources/views/admin/site-mail.phtml
index e9392dae2b..67259bbecd 100644
--- a/resources/views/admin/site-mail.phtml
+++ b/resources/views/admin/site-mail.phtml
@@ -13,7 +13,6 @@
 <form method="post" class="form-horizontal">
     <?= csrf_field() ?>
 
-    <!-- SMTP_ACTIVE -->
     <div class="row form-group">
         <label for="SMTP_ACTIVE" class="col-sm-3 col-form-label">
             <?= /* I18N: A configuration setting */ I18N::translate('Messages') ?>
@@ -26,7 +25,6 @@
         </div>
     </div>
 
-    <!-- SMTP_FROM_NAME -->
     <div class="row form-group">
         <label for="SMTP_FROM_NAME" class="col-sm-3 col-form-label">
             <?= /* I18N: A configuration setting */ I18N::translate('Sender name') ?>
@@ -41,7 +39,6 @@
 
     <h2><?= I18N::translate('SMTP mail server') ?></h2>
 
-    <!-- SMTP_HOST -->
     <div class="row form-group">
         <label for="SMTP_HOST" class="col-sm-3 col-form-label">
             <?= /* I18N: A configuration setting */ I18N::translate('Server name') ?>
@@ -54,7 +51,6 @@
         </div>
     </div>
 
-    <!-- SMTP_PORT -->
     <div class="row form-group">
         <label for="SMTP_PORT" class="col-sm-3 col-form-label">
             <?= /* I18N: A configuration setting */ I18N::translate('Port number') ?>
@@ -67,7 +63,6 @@
         </div>
     </div>
 
-    <!-- SMTP_AUTH -->
     <fieldset class="form-group">
         <div class="row">
             <legend class="col-form-label col-sm-3">
@@ -82,7 +77,6 @@
         </div>
     </fieldset>
 
-    <!-- SMTP_AUTH_USER -->
     <div class="row form-group">
         <label for="SMTP_AUTH_USER" class="col-sm-3 col-form-label">
             <?= /* I18N: A configuration setting */ I18N::translate('Username') ?>
@@ -95,7 +89,6 @@
         </div>
     </div>
 
-    <!-- SMTP_AUTH_PASS -->
     <div class="row form-group">
         <label for="SMTP_AUTH_PASS" class="col-sm-3 col-form-label">
             <?= /* I18N: A configuration setting */ I18N::translate('Password') ?>
@@ -108,7 +101,6 @@
         </div>
     </div>
 
-    <!-- SMTP_SSL -->
     <div class="row form-group">
         <label for="SMTP_SSL" class="col-sm-3 col-form-label">
             <?= /* I18N: A configuration setting */ I18N::translate('Secure connection') ?>
@@ -121,7 +113,6 @@
         </div>
     </div>
 
-    <!-- SMTP_HELO -->
     <div class="row form-group">
         <label for="SMTP_HELO" class="col-sm-3 col-form-label">
             <?= /* I18N: A configuration setting */ I18N::translate('Sending server name') ?>
@@ -134,6 +125,37 @@
         </div>
     </div>
 
+    <h2>
+        <?= /* I18N: https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail */ I18N::translate('DKIM digital signature') ?>
+    </h2>
+
+    <div class="row form-group">
+        <label for="DKIM_DOMAIN" class="col-sm-3 col-form-label">
+            <?= I18N::translate('Domain name') ?>
+        </label>
+        <div class="col-sm-9">
+            <input type="text" class="form-control" id="DKIM_DOMAIN" name="DKIM_DOMAIN" value="<?= e(Site::getPreference('DKIM_DOMAIN')) ?>" maxlength="255">
+        </div>
+    </div>
+
+    <div class="row form-group">
+        <label for="DKIM_SELECTOR" class="col-sm-3 col-form-label">
+            <?= I18N::translate('Selector') ?>
+        </label>
+        <div class="col-sm-9">
+            <input type="text" class="form-control" id="DKIM_SELECTOR" name="DKIM_SELECTOR" value="<?= e(Site::getPreference('DKIM_SELECTOR')) ?>" maxlength="255">
+        </div>
+    </div>
+
+    <div class="row form-group">
+        <label for="DKIM_KEY" class="col-sm-3 col-form-label">
+            <?= I18N::translate('Private key') ?>
+        </label>
+        <div class="col-sm-9">
+            <textarea class="form-control" id="DKIM_KEY" name="DKIM_KEY"><?= e(Site::getPreference('DKIM_KEY')) ?></textarea>
+        </div>
+    </div>
+
     <div class="row form-group">
         <div class="offset-sm-3 col-sm-9">
             <button type="submit" class="btn btn-primary">