Replacce previous fix for GSS auth hang on Windows

This commit reverts the previous GSS auth fix and replaces it with a
better one. While the previous change avoided the hang, it didn't
properly address the root cause of the problem, and didn't properly
maintain code coverage.

asyncssh/gss_win32.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2017-2021 by Ron Frederick <ronf@timeheart.net> and others.
+# Copyright (c) 2017-2022 by Ron Frederick <ronf@timeheart.net> and others.
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License v2.0 which accompanies this
@@ -109,8 +109,8 @@ def reset(self) -> None:
 
         assert self._ctx is not None
 
-        if self._ctx.authenticated:
-            self._ctx.reset()
+        self._ctx.reset()
+        self._init_token = None
 
     def step(self, token: Optional[bytes] = None) -> Optional[bytes]:
         """Perform next step in GSS security exchange"""

tests/sspi_stub.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2017-2019 by Ron Frederick <ronf@timeheart.net> and others.
+# Copyright (c) 2017-2022 by Ron Frederick <ronf@timeheart.net> and others.
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License v2.0 which accompanies this
@@ -105,7 +105,7 @@ def authorize(self, token):
 
         if self._error:
             self._error = False
-            raise SSPIError('Token authentication errror')
+            raise SSPIError('Token authentication error')
 
         new_token, complete = step(self._host, token)
 
@@ -114,7 +114,7 @@ def authorize(self, token):
 
         if new_token in (b'error', b'errtok'):
             if token:
-                raise SSPIError('Token authentication errror')
+                raise SSPIError('Token authentication error')
             else:
                 self._error = True
                 return True, [SSPIBuffer(b'')]

tests/test_auth.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2015-2021 by Ron Frederick <ronf@timeheart.net> and others.
+# Copyright (c) 2015-2022 by Ron Frederick <ronf@timeheart.net> and others.
 #
 # This program and the accompanying materials are made available under
 # the terms of the Eclipse Public License v2.0 which accompanies this
@@ -476,7 +476,7 @@ async def test_gss_auth(self):
         with self.subTest('GSS with MIC auth not available'):
             await self.check_auth(b'gssapi-with-mic', (False, None))
 
-        for steps in range(1, 4):
+        for steps in range(4):
             with self.subTest('GSS with MIC auth available'):
                 await self.check_auth(b'gssapi-with-mic', (True, None),
                                       gss_host=str(steps), success=True)