diff options
Diffstat (limited to 'lib/ssl/src/ssl_connection.erl')
| -rw-r--r-- | lib/ssl/src/ssl_connection.erl | 67 |
1 files changed, 63 insertions, 4 deletions
diff --git a/lib/ssl/src/ssl_connection.erl b/lib/ssl/src/ssl_connection.erl index bd17f19d10..5c7f76a28b 100644 --- a/lib/ssl/src/ssl_connection.erl +++ b/lib/ssl/src/ssl_connection.erl @@ -1515,13 +1515,18 @@ do_server_hello(Type, #hello_extensions{next_protocol_negotiation = NextProtocol ServerHelloExt, #state{negotiated_version = Version, session = #session{session_id = SessId}, - connection_states = ConnectionStates0} + connection_states = ConnectionStates0, + ssl_options = #ssl_options{versions = [HighestVersion|_]}} = State0, Connection) when is_atom(Type) -> - + %% TLS 1.3 - Section 4.1.3 + %% Override server random values for TLS 1.3 downgrade protection mechanism. + ConnectionStates1 = update_server_random(ConnectionStates0, Version, HighestVersion), + State1 = State0#state{connection_states = ConnectionStates1}, ServerHello = - ssl_handshake:server_hello(SessId, ssl:tls_version(Version), ConnectionStates0, ServerHelloExt), + ssl_handshake:server_hello(SessId, ssl:tls_version(Version), + ConnectionStates1, ServerHelloExt), State = server_hello(ServerHello, - State0#state{expecting_next_protocol_negotiation = + State1#state{expecting_next_protocol_negotiation = NextProtocols =/= undefined}, Connection), case Type of new -> @@ -1530,6 +1535,60 @@ do_server_hello(Type, #hello_extensions{next_protocol_negotiation = NextProtocol resumed_server_hello(State, Connection) end. +update_server_random(#{pending_read := #{security_parameters := ReadSecParams0} = + ReadState0, + pending_write := #{security_parameters := WriteSecParams0} = + WriteState0} = ConnectionStates, + Version, HighestVersion) -> + ReadRandom = override_server_random( + ReadSecParams0#security_parameters.server_random, + Version, + HighestVersion), + WriteRandom = override_server_random( + WriteSecParams0#security_parameters.server_random, + Version, + HighestVersion), + ReadSecParams = ReadSecParams0#security_parameters{server_random = ReadRandom}, + WriteSecParams = WriteSecParams0#security_parameters{server_random = WriteRandom}, + ReadState = ReadState0#{security_parameters => ReadSecParams}, + WriteState = WriteState0#{security_parameters => WriteSecParams}, + + ConnectionStates#{pending_read => ReadState, pending_write => WriteState}. + +%% TLS 1.3 - Section 4.1.3 +%% +%% If negotiating TLS 1.2, TLS 1.3 servers MUST set the last eight bytes +%% of their Random value to the bytes: +%% +%% 44 4F 57 4E 47 52 44 01 +%% +%% If negotiating TLS 1.1 or below, TLS 1.3 servers MUST and TLS 1.2 +%% servers SHOULD set the last eight bytes of their Random value to the +%% bytes: +%% +%% 44 4F 57 4E 47 52 44 00 +override_server_random(<<Random0:24/binary,_:8/binary>> = Random, {M,N}, {Major,Minor}) + when Major > 3 orelse Major =:= 3 andalso Minor >= 4 -> %% TLS 1.3 or above + if M =:= 3 andalso N =:= 3 -> %% Negotating TLS 1.2 + Down = ?RANDOM_OVERRIDE_TLS12, + <<Random0/binary,Down/binary>>; + M =:= 3 andalso N < 3 -> %% Negotating TLS 1.1 or prior + Down = ?RANDOM_OVERRIDE_TLS11, + <<Random0/binary,Down/binary>>; + true -> + Random + end; +override_server_random(<<Random0:24/binary,_:8/binary>> = Random, {M,N}, {Major,Minor}) + when Major =:= 3 andalso Minor =:= 3 -> %% TLS 1.2 + if M =:= 3 andalso N < 3 -> %% Negotating TLS 1.1 or prior + Down = ?RANDOM_OVERRIDE_TLS11, + <<Random0/binary,Down/binary>>; + true -> + Random + end; +override_server_random(Random, _, _) -> + Random. + new_server_hello(#server_hello{cipher_suite = CipherSuite, compression_method = Compression, session_id = SessionId}, |