ssl: ERL-738 - Correct alert handling with new TLS sender process

With the new TLS sender process, solving ERL-622, TLS ALERTs sent in
the connection state must be encrypted and sent by the TLS sender
process. This to make sure that the correct encryption state is used
to encode the ALERTS. Care must also be taken to ensure a graceful
close down behavior both for normal shutdown and downgrading from TLS
to TCP.

The original TR ERL-738 is verified by cowboy tests, and close down
behavior by our tests. However we alas have not been able to yet
create a minimal test case for the originating problem.

Also it seems it has become less likely that we run in to the TCP
delivery problem, that is the guarantee is only on transport level,
not application level. Keep work around function in ssl_test_lib but
we can have better test as long as we do not get to much wobbling
tests.

1 files changed, 25 insertions, 23 deletions

diff --git a/lib/ssl/src/ssl_connection.erl b/lib/ssl/src/ssl_connection.erl
index 5ea1924d40..9f876add6c 100644
--- a/lib/ssl/src/ssl_connection.erl
+++ b/lib/ssl/src/ssl_connection.erl
@@ -334,17 +334,12 @@ prf(ConnectionPid, Secret, Label, Seed, WantedLength) ->
 %%====================================================================
 %% Alert and close handling
 %%====================================================================
-handle_own_alert(Alert, Version, StateName, 
+handle_own_alert(Alert, _, StateName,
 		 #state{role = Role,
-                        transport_cb = Transport,
-                        socket = Socket,
                         protocol_cb = Connection,
-                        connection_states = ConnectionStates,
                         ssl_options = SslOpts} = State) ->
     try %% Try to tell the other side
-	{BinMsg, _} =
-            Connection:encode_alert(Alert, Version, ConnectionStates),
-	Connection:send(Transport, Socket, BinMsg)
+        send_alert(Alert, StateName, State)
     catch _:_ ->  %% Can crash if we are in a uninitialized state
 	    ignore
     end,
@@ -1160,24 +1155,20 @@ handle_call({close, {Pid, Timeout}}, From, StateName, State0, Connection) when i
     %% we must recive the close alert from the peer before releasing the 
     %% transport socket.
     {next_state, downgrade, State#state{terminated = true}, [{timeout, Timeout, downgrade}]};
-handle_call({close, _} = Close, From, StateName, State, Connection) ->
+handle_call({close, _} = Close, From, StateName, State, _Connection) ->
     %% Run terminate before returning so that the reuseaddr
     %% inet-option works properly
-    Result = Connection:terminate(Close, StateName, State#state{terminated = true}),
+    Result = terminate(Close, StateName, State),
     stop_and_reply(
       {shutdown, normal},
-      {reply, From, Result}, State);
-handle_call({shutdown, How0}, From, _,
+      {reply, From, Result}, State#state{terminated = true});
+handle_call({shutdown, How0}, From, StateName,
 	    #state{transport_cb = Transport,
-		   negotiated_version = Version,
-		   connection_states = ConnectionStates,
-		   socket = Socket} = State, Connection) ->
+		   socket = Socket} = State, _) ->
     case How0 of
 	How when How == write; How == both ->	    
-	    Alert = ?ALERT_REC(?WARNING, ?CLOSE_NOTIFY),
-	    {BinMsg, _} =
-		Connection:encode_alert(Alert, Version, ConnectionStates),
-	    Connection:send(Transport, Socket, BinMsg);
+            send_alert(?ALERT_REC(?WARNING, ?CLOSE_NOTIFY),
+                       StateName, State);
 	_ ->
 	    ok
     end,
@@ -1343,14 +1334,20 @@ terminate({shutdown, own_alert}, _StateName, #state{
 	_ ->
 	    Connection:close({timeout, ?DEFAULT_TIMEOUT}, Socket, Transport, undefined, undefined)
     end;
+terminate(downgrade = Reason, connection, #state{protocol_cb = Connection,
+                                        transport_cb = Transport, socket = Socket
+                                       } = State) ->
+    handle_trusted_certs_db(State),
+    Connection:close(Reason, Socket, Transport, undefined, undefined);
 terminate(Reason, connection, #state{protocol_cb = Connection,
-				     connection_states = ConnectionStates, 
-				     ssl_options = #ssl_options{padding_check = Check},
-				     transport_cb = Transport, socket = Socket
-				    } = State) ->
+                                                connection_states = ConnectionStates,
+                                                ssl_options = #ssl_options{padding_check = Check},
+                                                transport_cb = Transport, socket = Socket
+                                               } = State) ->
     handle_trusted_certs_db(State),
     Alert = terminate_alert(Reason),
-    ok = Connection:send_alert_in_connection(Alert, State),
+    %% Send the termination ALERT if possible
+    catch (ok = Connection:send_alert_in_connection(Alert, State)),
     Connection:close(Reason, Socket, Transport, ConnectionStates, Check);
 terminate(Reason, _StateName, #state{transport_cb = Transport, protocol_cb = Connection,
 				     socket = Socket 
@@ -1387,6 +1384,11 @@ format_status(terminate, [_, StateName, State]) ->
 %%--------------------------------------------------------------------
 %%% Internal functions
 %%--------------------------------------------------------------------
+send_alert(Alert, connection, #state{protocol_cb = Connection} = State) ->
+     Connection:send_alert_in_connection(Alert, State);
+send_alert(Alert, _, #state{protocol_cb = Connection} = State) ->
+    Connection:send_alert(Alert, State).
+
 connection_info(#state{sni_hostname = SNIHostname, 
 		       session = #session{session_id = SessionId,
                                           cipher_suite = CipherSuite, ecc = ECCCurve},