Issue #1027206: getnameinfo is now restricted to numeric addresses as input.

Lib/test/test_socket.py

@@ -637,6 +637,10 @@ class GeneralModuleTests(unittest.TestCase):
                                flags=socket.AI_PASSIVE)
         self.assertEqual(a, b)
 
+    def test_getnameinfo(self):
+        # only IP addresses are allowed
+        self.assertRaises(socket.error, socket.getnameinfo, ('mail.python.org',0), 0)
+
     def test_idna(self):
         # these should all be successful
         socket.gethostbyname('испытание.python.org')

Misc/NEWS

@@ -70,7 +70,8 @@ Extensions
 ----------
 
 - Issue #1027206: Support IDNA in gethostbyname, gethostbyname_ex, 
-  getaddrinfo and gethostbyaddr.
+  getaddrinfo and gethostbyaddr. getnameinfo is now restricted to numeric
+  addresses as input.
 
 - Issue #9214: Set operations on a KeysView or ItemsView in collections
   now correctly return a set.  (Patch by Eli Bendersky.)

Modules/socketmodule.c

@@ -3969,6 +3969,7 @@ socket_getnameinfo(PyObject *self, PyObject *args)
     memset(&hints, 0, sizeof(hints));
     hints.ai_family = AF_UNSPEC;
     hints.ai_socktype = SOCK_DGRAM;     /* make numeric port happy */
+    hints.ai_flags = AI_NUMERICHOST;    /* don't do any name resolution */
     Py_BEGIN_ALLOW_THREADS
     ACQUIRE_GETADDRINFO_LOCK
     error = getaddrinfo(hostp, pbuf, &hints, &res);