Pass bytes to idna

salt/utils/network.py

@@ -137,7 +137,12 @@ def _generate_minion_id():
         def first(self):
             return self and self[0] or None
 
-    hosts = DistinctList().append(socket.getfqdn()).append(platform.node()).append(socket.gethostname())
+    hostname = socket.gethostname()
+
+    hosts = DistinctList().append(
+        salt.utils.stringutils.to_unicode(socket.getfqdn(salt.utils.stringutils.to_bytes(hostname)))
+    )
+    hosts.append(platform.node()).append(hostname)
     if not hosts:
         try:
             for a_nfo in socket.getaddrinfo(hosts.first() or 'localhost', None, socket.AF_INET,

tests/unit/utils/test_network.py

@@ -534,3 +534,16 @@ class NetworkTestCase(TestCase):
         self.assertRaises(ValueError, network.mac_str_to_bytes, 'a0:b0:c0:d0:e0:fg')
         self.assertEqual(b'\x10\x08\x06\x04\x02\x00', network.mac_str_to_bytes('100806040200'))
         self.assertEqual(b'\xf8\xe7\xd6\xc5\xb4\xa3', network.mac_str_to_bytes('f8e7d6c5b4a3'))
+
+    def test_generate_minion_id_with_long_hostname(self):
+        '''
+        Validate the fix for:
+
+        https://github.com/saltstack/salt/issues/51160
+        '''
+        long_name = 'localhost-abcdefghijklmnopqrstuvwxyz-abcdefghijklmnopqrstuvwxyz'
+        with patch('socket.gethostname', MagicMock(return_value=long_name)):
+            # An exception is raised if unicode is passed to socket.getfqdn 
+            minion_id = network.generate_minion_id()
+        assert minion_id != '', minion_id
+