From 5d11691de77d117b58f722857d79a04e2f1e278d Mon Sep 17 00:00:00 2001
From: Jakub Warmuz <jakub@warmuz.org>
Date: Tue, 27 Oct 2015 22:19:21 +0000
Subject: [PATCH] Standalone verifies ports for suported challenges only (fixes
 #1149).

---
 letsencrypt/plugins/standalone.py      | 12 ++++++++++--
 letsencrypt/plugins/standalone_test.py | 13 +++++++++----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/letsencrypt/plugins/standalone.py b/letsencrypt/plugins/standalone.py
index d4dddc7f6..5d2dafc7d 100644
--- a/letsencrypt/plugins/standalone.py
+++ b/letsencrypt/plugins/standalone.py
@@ -181,6 +181,15 @@ class Authenticator(common.Plugin):
         return set(challenges.Challenge.TYPES[name] for name in
                    self.conf("supported-challenges").split(","))
 
+    @property
+    def _necessary_ports(self):
+        necessary_ports = set()
+        if challenges.SimpleHTTP in self.supported_challenges:
+            necessary_ports.add(self.config.simple_http_port)
+        if challenges.DVSNI in self.supported_challenges:
+            necessary_ports.add(self.config.dvsni_port)
+        return necessary_ports
+
     def more_info(self):  # pylint: disable=missing-docstring
         return self.__doc__
 
@@ -194,8 +203,7 @@ class Authenticator(common.Plugin):
         return chall_pref
 
     def perform(self, achalls):  # pylint: disable=missing-docstring
-        if any(util.already_listening(port) for port in
-               (self.config.dvsni_port, self.config.simple_http_port)):
+        if any(util.already_listening(port) for port in self._necessary_ports):
             raise errors.MisconfigurationError(
                 "At least one of the (possibly) required ports is "
                 "already taken.")
diff --git a/letsencrypt/plugins/standalone_test.py b/letsencrypt/plugins/standalone_test.py
index 0ccdccb1f..3a6941be8 100644
--- a/letsencrypt/plugins/standalone_test.py
+++ b/letsencrypt/plugins/standalone_test.py
@@ -107,10 +107,15 @@ class AuthenticatorTest(unittest.TestCase):
                          set([challenges.DVSNI, challenges.SimpleHTTP]))
 
     @mock.patch("letsencrypt.plugins.standalone.util")
-    def test_perform_misconfiguration(self, mock_util):
-        mock_util.already_listening.return_value = True
-        self.assertRaises(errors.MisconfigurationError, self.auth.perform, [])
-        mock_util.already_listening.assert_called_once_with(1234)
+    def test_perform_alredy_listening(self, mock_util):
+        for chall, port in ((challenges.DVSNI.typ, 1234),
+                            (challenges.SimpleHTTP.typ, 4321)):
+            mock_util.already_listening.return_value = True
+            self.config.standalone_supported_challenges = chall
+            self.assertRaises(
+                errors.MisconfigurationError, self.auth.perform, [])
+            mock_util.already_listening.assert_called_once_with(port)
+            mock_util.already_listening.reset_mock()
 
     @mock.patch("letsencrypt.plugins.standalone.zope.component.getUtility")
     def test_perform(self, unused_mock_get_utility):