ssl: Application data optimization must be done differently for TLS-1.3 and previous versions

TLS-1.3 encrypts the real packet type and uses APPLICATION_DATA
as external type.  The optimization will disregard the last
decryption if next packet is not APPLICATION_DATA.  This however
will not work for pre TLS-1.3 and stream cipher RC4, after the
optimization to stream ciphers making the crypto API pure
functional. In TLS-1.3 no stream ciphers are supported. In
previous TLS versions we can look at the external packet type
with out decryption.

1 files changed, 32 insertions, 1 deletions

diff --git a/lib/ssl/src/tls_connection.erl b/lib/ssl/src/tls_connection.erl
index b4754e9f55..cfd1ca3932 100644
--- a/lib/ssl/src/tls_connection.erl
+++ b/lib/ssl/src/tls_connection.erl
@@ -221,7 +221,7 @@ activate_socket(#state{protocol_specific = #{active_n_toggle := true, active_n :
 next_record(State, CipherTexts, ConnectionStates, Check) ->
     next_record(State, CipherTexts, ConnectionStates, Check, []).
 %%
-next_record(#state{connection_env = #connection_env{negotiated_version = Version}} = State,
+next_record(#state{connection_env = #connection_env{negotiated_version = {3,4} = Version}} = State,
             [CT|CipherTexts], ConnectionStates0, Check, Acc) ->
     case tls_record:decode_cipher_text(Version, CT, ConnectionStates0, Check) of
         {#ssl_tls{type = ?APPLICATION_DATA, fragment = Fragment}, ConnectionStates} ->
@@ -242,10 +242,41 @@ next_record(#state{connection_env = #connection_env{negotiated_version = Version
             %% Not ?APPLICATION_DATA but we have accumulated fragments
             %% -> build an ?APPLICATION_DATA record with concatenated fragments
             %%    and forget about decrypting this record - we'll decrypt it again next time
+            %% Will not work for stream ciphers
             next_record_done(State, [CT|CipherTexts], ConnectionStates0,
                              #ssl_tls{type = ?APPLICATION_DATA, fragment = iolist_to_binary(lists:reverse(Acc))});
         #alert{} = Alert ->
             Alert
+    end;
+next_record(#state{connection_env = #connection_env{negotiated_version = Version}} = State,
+            [#ssl_tls{type = ?APPLICATION_DATA} = CT |CipherTexts], ConnectionStates0, Check, Acc) ->
+    case tls_record:decode_cipher_text(Version, CT, ConnectionStates0, Check) of
+        {#ssl_tls{type = ?APPLICATION_DATA, fragment = Fragment}, ConnectionStates} ->
+            case CipherTexts of
+                [] ->
+                    %% End of cipher texts - build and deliver an ?APPLICATION_DATA record
+                    %% from the accumulated fragments
+                    next_record_done(State, [], ConnectionStates,
+                                     #ssl_tls{type = ?APPLICATION_DATA,
+                                              fragment = iolist_to_binary(lists:reverse(Acc, [Fragment]))});
+                [_|_] ->
+                    next_record(State, CipherTexts, ConnectionStates, Check, [Fragment|Acc])
+            end;
+        #alert{} = Alert ->
+            Alert
+    end;
+next_record(State, CipherTexts, ConnectionStates, _, [_|_] = Acc) ->
+    next_record_done(State, CipherTexts, ConnectionStates,
+                     #ssl_tls{type = ?APPLICATION_DATA,
+                              fragment = iolist_to_binary(lists:reverse(Acc))});
+next_record(#state{connection_env = #connection_env{negotiated_version = Version}} = State,
+            [CT|CipherTexts], ConnectionStates0, Check, []) ->
+    case tls_record:decode_cipher_text(Version, CT, ConnectionStates0, Check) of      
+        {Record, ConnectionStates} ->
+            %% Singelton non-?APPLICATION_DATA record - deliver
+            next_record_done(State, CipherTexts, ConnectionStates, Record);
+        #alert{} = Alert ->
+            Alert
     end.
 
 next_record_done(#state{protocol_buffers = Buffers} = State, CipherTexts, ConnectionStates, Record) ->