GH-113214: Fix SSLProto exception handling in SSL-over-SSL scenarios (#113334)

When wrapped, `_SSLProtocolTransport._force_close(exc)` is called just like in the unwrapped scenario `_SelectorTransport._force_close(exc)` or `_ProactorBasePipeTransport._force_close(exc)` would be called, except here the exception needs to be passed through the `SSLProtocol._abort()` method, which didn't accept an exception object.

This commit ensures that this path works, in the same way that the uvloop implementation of SSLProto passes on the exception (on which the current implementation of SSLProto is based).

Author: mjpieters

Lib/asyncio/sslproto.py

@@ -243,13 +243,12 @@ def abort(self):
         The protocol's connection_lost() method will (eventually) be
         called with None as its argument.
         """
-        self._closed = True
-        if self._ssl_protocol is not None:
-            self._ssl_protocol._abort()
+        self._force_close(None)
 
     def _force_close(self, exc):
         self._closed = True
-        self._ssl_protocol._abort(exc)
+        if self._ssl_protocol is not None:
+            self._ssl_protocol._abort(exc)
 
     def _test__append_write_backlog(self, data):
         # for test only
@@ -614,7 +613,7 @@ def _start_shutdown(self):
         if self._app_transport is not None:
             self._app_transport._closed = True
         if self._state == SSLProtocolState.DO_HANDSHAKE:
-            self._abort()
+            self._abort(None)
         else:
             self._set_state(SSLProtocolState.FLUSHING)
             self._shutdown_timeout_handle = self._loop.call_later(
@@ -661,10 +660,10 @@ def _on_shutdown_complete(self, shutdown_exc):
         else:
             self._loop.call_soon(self._transport.close)
 
-    def _abort(self):
+    def _abort(self, exc):
         self._set_state(SSLProtocolState.UNWRAPPED)
         if self._transport is not None:
-            self._transport.abort()
+            self._transport._force_close(exc)
 
     # Outgoing flow
 

Lib/test/test_asyncio/test_sslproto.py

@@ -47,6 +47,7 @@ def connection_made(self, ssl_proto, *, do_handshake=None):
         sslobj = mock.Mock()
         # emulate reading decompressed data
         sslobj.read.side_effect = ssl.SSLWantReadError
+        sslobj.write.side_effect = ssl.SSLWantReadError
         if do_handshake is not None:
             sslobj.do_handshake = do_handshake
         ssl_proto._sslobj = sslobj
@@ -120,7 +121,19 @@ def test_close_during_handshake(self):
         test_utils.run_briefly(self.loop)
 
         ssl_proto._app_transport.close()
-        self.assertTrue(transport.abort.called)
+        self.assertTrue(transport._force_close.called)
+
+    def test_close_during_ssl_over_ssl(self):
+        # gh-113214: passing exceptions from the inner wrapped SSL protocol to the
+        # shim transport provided by the outer SSL protocol should not raise
+        # attribute errors
+        outer = self.ssl_protocol(proto=self.ssl_protocol())
+        self.connection_made(outer)
+        # Closing the outer app transport should not raise an exception
+        messages = []
+        self.loop.set_exception_handler(lambda loop, ctx: messages.append(ctx))
+        outer._app_transport.close()
+        self.assertEqual(messages, [])
 
     def test_get_extra_info_on_closed_connection(self):
         waiter = self.loop.create_future()

Misc/NEWS.d/next/Library/2023-12-20-21-18-51.gh-issue-113214.JcV9Mn.rst

@@ -0,0 +1 @@
+Fix an ``AttributeError`` during asyncio SSL protocol aborts in SSL-over-SSL scenarios.