Merge branch 'raimo/ssl/version-selection/maint-18/OTP-13753' into maint-18

* raimo/ssl/version-selection/maint-18/OTP-13753:
  Improve version selection

1 files changed, 35 insertions, 3 deletions

diff --git a/lib/ssl/src/ssl_handshake.erl b/lib/ssl/src/ssl_handshake.erl
index 235d6efbb6..43b0c42f8d 100644
--- a/lib/ssl/src/ssl_handshake.erl
+++ b/lib/ssl/src/ssl_handshake.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2013-2015. All Rights Reserved.
+%% Copyright Ericsson AB 2013-2016. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -1258,8 +1258,40 @@ handle_server_hello_extensions(RecordCB, Random, CipherSuite, Compression,
     end.
 
 select_version(RecordCB, ClientVersion, Versions) ->
-    ServerVersion = RecordCB:highest_protocol_version(Versions),
-    RecordCB:lowest_protocol_version(ClientVersion, ServerVersion).
+    do_select_version(RecordCB, ClientVersion, Versions).
+
+do_select_version(_, ClientVersion, []) ->
+    ClientVersion;
+do_select_version(RecordCB, ClientVersion, [Version | Versions]) ->
+    case RecordCB:is_higher(Version, ClientVersion) of
+	true ->
+	    %% Version too high for client - keep looking
+	    do_select_version(RecordCB, ClientVersion, Versions);
+	false ->
+	    %% Version ok for client - look for a higher
+	    do_select_version(RecordCB, ClientVersion, Versions, Version)
+    end.
+%%
+do_select_version(_, _, [], GoodVersion) ->
+    GoodVersion;
+do_select_version(
+  RecordCB, ClientVersion, [Version | Versions], GoodVersion) ->
+    BetterVersion =
+	case RecordCB:is_higher(Version, ClientVersion) of
+	    true ->
+		%% Version too high for client
+		GoodVersion;
+	    false ->
+		%% Version ok for client
+		case RecordCB:is_higher(Version, GoodVersion) of
+		    true ->
+			%% Use higher version
+			Version;
+		    false ->
+			GoodVersion
+		end
+	end,
+    do_select_version(RecordCB, ClientVersion, Versions, BetterVersion).
 
 renegotiation_info(_, client, _, false) ->
     #renegotiation_info{renegotiated_connection = undefined};