Restore support for ManageSieve over implicit SSL. (#8670)

2 files changed, 8 insertions, 1 deletions

diff --git a/plugins/managesieve/config.inc.php.dist b/plugins/managesieve/config.inc.php.dist
index 354709586..28029e3b1 100644
--- a/plugins/managesieve/config.inc.php.dist
+++ b/plugins/managesieve/config.inc.php.dist
@@ -8,7 +8,8 @@
 // For example %n = mail.domain.tld, %d = domain.tld
 // If port is omitted it will be determined automatically using getservbyname()
 // function, with 4190 as a fallback.
-// Note: Add tls:// prefix to enable TLS
+// Note: Add tls:// prefix to enable explicit STARTTLS
+// or add ssl:// prefix to enable implicit SSL.
 $config['managesieve_host'] = 'localhost';
 
 // authentication method. Can be CRAM-MD5, DIGEST-MD5, PLAIN, LOGIN, EXTERNAL
diff --git a/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php b/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php
index ce6bc384c..a09f456e6 100644
--- a/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php
+++ b/plugins/managesieve/lib/Roundcube/rcube_sieve_engine.php
@@ -184,8 +184,14 @@ class rcube_sieve_engine
 
         list($host, $scheme, $port) = rcube_utils::parse_host_uri($plugin['host']);
 
+        // Support explicit STARTTLS by establishing an unencrypted TCP connection, then instructing Net_Sieve to send the `STARTTLS` command.
         $tls = $scheme === 'tls';
 
+        // Support implicit SSL by passing the URI scheme through to Net_Sieve -> Net_Socket -> stream_socket_client().
+        if ($scheme === 'ssl') {
+            $host = 'ssl://' . $host;
+        }
+
         if (empty($port)) {
             $port = getservbyname('sieve', 'tcp') ?: self::PORT;
         }