diff options
Diffstat (limited to 'lib/ssl/src/dtls_connection.erl')
| -rw-r--r-- | lib/ssl/src/dtls_connection.erl | 388 |
1 files changed, 292 insertions, 96 deletions
diff --git a/lib/ssl/src/dtls_connection.erl b/lib/ssl/src/dtls_connection.erl index 745db788e7..a352b7e025 100644 --- a/lib/ssl/src/dtls_connection.erl +++ b/lib/ssl/src/dtls_connection.erl @@ -45,15 +45,15 @@ -export([renegotiate/2, reinit_handshake_data/1, send_handshake/2, queue_handshake/2, queue_change_cipher/2, - select_sni_extension/1]). + select_sni_extension/1, empty_connection_state/2]). %% Alert and close handling --export([encode_alert/3,send_alert/2, close/5]). +-export([encode_alert/3,send_alert/2, close/5, protocol_name/0]). %% Data handling -export([encode_data/3, passive_receive/2, next_record_if_active/1, handle_common_event/4, - send/3, socket/5]). + send/3, socket/5, setopts/3, getopts/3]). %% gen_statem state functions -export([init/3, error/3, downgrade/3, %% Initiation and take down states @@ -79,9 +79,9 @@ start_fsm(Role, Host, Port, Socket, {#ssl_options{erl_dist = false},_, Tracker} Error end. -send_handshake(Handshake, #state{connection_states = ConnectionStates} = States) -> +send_handshake(Handshake, #state{connection_states = ConnectionStates} = State) -> #{epoch := Epoch} = ssl_record:current_connection_state(ConnectionStates, write), - send_handshake_flight(queue_handshake(Handshake, States), Epoch). + send_handshake_flight(queue_handshake(Handshake, State), Epoch). queue_handshake(Handshake0, #state{tls_handshake_history = Hist0, negotiated_version = Version, @@ -114,8 +114,8 @@ send_handshake_flight(#state{socket = Socket, %% TODO remove hardcoded Max size {Encoded, ConnectionStates} = encode_handshake_flight(lists:reverse(Flight), Version, 1400, Epoch, ConnectionStates0), - send(Transport, Socket, Encoded), - start_flight(State0#state{connection_states = ConnectionStates}); + send(Transport, Socket, Encoded), + {State0#state{connection_states = ConnectionStates}, []}; send_handshake_flight(#state{socket = Socket, transport_cb = Transport, @@ -129,7 +129,7 @@ send_handshake_flight(#state{socket = Socket, {EncChangeCipher, ConnectionStates} = encode_change_cipher(ChangeCipher, Version, Epoch, ConnectionStates1), send(Transport, Socket, [HsBefore, EncChangeCipher]), - start_flight(State0#state{connection_states = ConnectionStates}); + {State0#state{connection_states = ConnectionStates}, []}; send_handshake_flight(#state{socket = Socket, transport_cb = Transport, @@ -145,7 +145,7 @@ send_handshake_flight(#state{socket = Socket, {HsAfter, ConnectionStates} = encode_handshake_flight(lists:reverse(Flight1), Version, 1400, Epoch, ConnectionStates2), send(Transport, Socket, [HsBefore, EncChangeCipher, HsAfter]), - start_flight(State0#state{connection_states = ConnectionStates}); + {State0#state{connection_states = ConnectionStates}, []}; send_handshake_flight(#state{socket = Socket, transport_cb = Transport, @@ -159,7 +159,7 @@ send_handshake_flight(#state{socket = Socket, {HsAfter, ConnectionStates} = encode_handshake_flight(lists:reverse(Flight1), Version, 1400, Epoch, ConnectionStates1), send(Transport, Socket, [EncChangeCipher, HsAfter]), - start_flight(State0#state{connection_states = ConnectionStates}). + {State0#state{connection_states = ConnectionStates}, []}. queue_change_cipher(ChangeCipher, #state{flight_buffer = Flight, connection_states = ConnectionStates0} = State) -> @@ -188,9 +188,10 @@ reinit_handshake_data(#state{protocol_buffers = Buffers} = State) -> public_key_info = undefined, tls_handshake_history = ssl_handshake:init_handshake_history(), flight_state = {retransmit, ?INITIAL_RETRANSMIT_TIMEOUT}, - protocol_buffers = + flight_buffer = new_flight(), + protocol_buffers = Buffers#protocol_buffers{ - dtls_handshake_next_seq = 0, + dtls_handshake_next_seq = 0, dtls_handshake_next_fragments = [], dtls_handshake_later_fragments = [] }}. @@ -199,10 +200,21 @@ select_sni_extension(#client_hello{extensions = HelloExtensions}) -> HelloExtensions#hello_extensions.sni; select_sni_extension(_) -> undefined. +empty_connection_state(ConnectionEnd, BeastMitigation) -> + Empty = ssl_record:empty_connection_state(ConnectionEnd, BeastMitigation), + dtls_record:empty_connection_state(Empty). socket(Pid, Transport, Socket, Connection, _) -> dtls_socket:socket(Pid, Transport, Socket, Connection). +setopts(Transport, Socket, Other) -> + dtls_socket:setopts(Transport, Socket, Other). +getopts(Transport, Socket, Tag) -> + dtls_socket:getopts(Transport, Socket, Tag). + +protocol_name() -> + "DTLS". + %%==================================================================== %% tls_connection_sup API %%==================================================================== @@ -230,12 +242,14 @@ init([Role, Host, Port, Socket, Options, User, CbInfo]) -> end. callback_mode() -> - state_functions. + [state_functions, state_enter]. %%-------------------------------------------------------------------- %% State functions %%-------------------------------------------------------------------- +init(enter, _, State) -> + {keep_state, State}; init({call, From}, {start, Timeout}, #state{host = Host, port = Port, role = client, ssl_options = SslOpts, @@ -250,7 +264,7 @@ init({call, From}, {start, Timeout}, Cache, CacheCb, Renegotiation, Cert), Version = Hello#client_hello.client_version, - HelloVersion = dtls_record:lowest_protocol_version(SslOpts#ssl_options.versions), + HelloVersion = dtls_record:hello_version(Version, SslOpts#ssl_options.versions), State1 = prepare_flight(State0#state{negotiated_version = Version}), {State2, Actions} = send_handshake(Hello, State1#state{negotiated_version = HelloVersion}), State3 = State2#state{negotiated_version = Version, %% Requested version @@ -263,15 +277,24 @@ init({call, From}, {start, Timeout}, {Record, State} = next_record(State3), next_event(hello, Record, State, Actions); init({call, _} = Type, Event, #state{role = server, transport_cb = gen_udp} = State) -> - ssl_connection:init(Type, Event, - State#state{flight_state = {retransmit, ?INITIAL_RETRANSMIT_TIMEOUT}}, - ?MODULE); + Result = ssl_connection:init(Type, Event, + State#state{flight_state = {retransmit, ?INITIAL_RETRANSMIT_TIMEOUT}, + protocol_specific = #{current_cookie_secret => dtls_v1:cookie_secret(), + previous_cookie_secret => <<>>, + ignored_alerts => 0, + max_ignored_alerts => 10}}, + ?MODULE), + erlang:send_after(dtls_v1:cookie_timeout(), self(), new_cookie_secret), + Result; + init({call, _} = Type, Event, #state{role = server} = State) -> %% I.E. DTLS over sctp ssl_connection:init(Type, Event, State#state{flight_state = reliable}, ?MODULE); init(Type, Event, State) -> ssl_connection:init(Type, Event, State, ?MODULE). +error(enter, _, State) -> + {keep_state, State}; error({call, From}, {start, _Timeout}, {Error, State}) -> {stop_and_reply, normal, {reply, From, {error, Error}}, State}; error({call, From}, Msg, State) -> @@ -285,29 +308,46 @@ error(_, _, _) -> #state{}) -> gen_statem:state_function_result(). %%-------------------------------------------------------------------- +hello(enter, _, #state{role = server} = State) -> + {keep_state, State}; +hello(enter, _, #state{role = client} = State0) -> + {State, Actions} = handle_flight_timer(State0), + {keep_state, State, Actions}; hello(internal, #client_hello{cookie = <<>>, client_version = Version} = Hello, #state{role = server, transport_cb = Transport, - socket = Socket} = State0) -> - %% TODO: not hard code key + socket = Socket, + protocol_specific = #{current_cookie_secret := Secret}} = State0) -> {ok, {IP, Port}} = dtls_socket:peername(Transport, Socket), - Cookie = dtls_handshake:cookie(<<"secret">>, IP, Port, Hello), - VerifyRequest = dtls_handshake:hello_verify_request(Cookie, Version), + Cookie = dtls_handshake:cookie(Secret, IP, Port, Hello), + %% FROM RFC 6347 regarding HelloVerifyRequest message: + %% The server_version field has the same syntax as in TLS. However, in + %% order to avoid the requirement to do version negotiation in the + %% initial handshake, DTLS 1.2 server implementations SHOULD use DTLS + %% version 1.0 regardless of the version of TLS that is expected to be + %% negotiated. + VerifyRequest = dtls_handshake:hello_verify_request(Cookie, ?HELLO_VERIFY_REQUEST_VERSION), State1 = prepare_flight(State0#state{negotiated_version = Version}), {State2, Actions} = send_handshake(VerifyRequest, State1), {Record, State} = next_record(State2), next_event(hello, Record, State#state{tls_handshake_history = ssl_handshake:init_handshake_history()}, Actions); hello(internal, #client_hello{cookie = Cookie} = Hello, #state{role = server, transport_cb = Transport, - socket = Socket} = State0) -> + socket = Socket, + protocol_specific = #{current_cookie_secret := Secret, + previous_cookie_secret := PSecret}} = State0) -> {ok, {IP, Port}} = dtls_socket:peername(Transport, Socket), - %% TODO: not hard code key - case dtls_handshake:cookie(<<"secret">>, IP, Port, Hello) of + case dtls_handshake:cookie(Secret, IP, Port, Hello) of Cookie -> handle_client_hello(Hello, State0); _ -> - %% Handle bad cookie as new cookie request RFC 6347 4.1.2 - hello(internal, Hello#client_hello{cookie = <<>>}, State0) + case dtls_handshake:cookie(PSecret, IP, Port, Hello) of + Cookie -> + handle_client_hello(Hello, State0); + _ -> + %% Handle bad cookie as new cookie request RFC 6347 4.1.2 + hello(internal, Hello#client_hello{cookie = <<>>}, State0) + end end; hello(internal, #hello_verify_request{cookie = Cookie}, #state{role = client, host = Host, port = Port, @@ -319,13 +359,14 @@ hello(internal, #hello_verify_request{cookie = Cookie}, #state{role = client, session_cache = Cache, session_cache_cb = CacheCb } = State0) -> - State1 = prepare_flight(State0#state{tls_handshake_history = ssl_handshake:init_handshake_history()}), + Hello = dtls_handshake:client_hello(Host, Port, Cookie, ConnectionStates0, SslOpts, Cache, CacheCb, Renegotiation, OwnCert), Version = Hello#client_hello.client_version, - HelloVersion = dtls_record:lowest_protocol_version(SslOpts#ssl_options.versions), - {State2, Actions} = send_handshake(Hello, State1#state{negotiated_version = HelloVersion}), + State1 = prepare_flight(State0#state{tls_handshake_history = ssl_handshake:init_handshake_history()}), + + {State2, Actions} = send_handshake(Hello, State1), State3 = State2#state{negotiated_version = Version, %% Requested version session = Session0#session{session_id = @@ -340,7 +381,7 @@ hello(internal, #server_hello{} = Hello, ssl_options = SslOptions} = State) -> case dtls_handshake:hello(Hello, SslOptions, ConnectionStates0, Renegotiation) of #alert{} = Alert -> - ssl_connection:handle_own_alert(Alert, ReqVersion, hello, State); + handle_own_alert(Alert, ReqVersion, hello, State); {Version, NewId, ConnectionStates, ProtoExt, Protocol} -> ssl_connection:handle_session(Hello, Version, NewId, ConnectionStates, ProtoExt, Protocol, State) @@ -358,6 +399,9 @@ hello(state_timeout, Event, State) -> hello(Type, Event, State) -> ssl_connection:hello(Type, Event, State, ?MODULE). +abbreviated(enter, _, State0) -> + {State, Actions} = handle_flight_timer(State0), + {keep_state, State, Actions}; abbreviated(info, Event, State) -> handle_info(Event, abbreviated, State); abbreviated(internal = Type, @@ -375,6 +419,9 @@ abbreviated(state_timeout, Event, State) -> abbreviated(Type, Event, State) -> ssl_connection:abbreviated(Type, Event, State, ?MODULE). +certify(enter, _, State0) -> + {State, Actions} = handle_flight_timer(State0), + {keep_state, State, Actions}; certify(info, Event, State) -> handle_info(Event, certify, State); certify(internal = Type, #server_hello_done{} = Event, State) -> @@ -384,6 +431,9 @@ certify(state_timeout, Event, State) -> certify(Type, Event, State) -> ssl_connection:certify(Type, Event, State, ?MODULE). +cipher(enter, _, State0) -> + {State, Actions} = handle_flight_timer(State0), + {keep_state, State, Actions}; cipher(info, Event, State) -> handle_info(Event, cipher, State); cipher(internal = Type, #change_cipher_spec{type = <<1>>} = Event, @@ -401,20 +451,27 @@ cipher(state_timeout, Event, State) -> cipher(Type, Event, State) -> ssl_connection:cipher(Type, Event, State, ?MODULE). +connection(enter, _, State) -> + {keep_state, State}; connection(info, Event, State) -> handle_info(Event, connection, State); connection(internal, #hello_request{}, #state{host = Host, port = Port, - session = #session{own_certificate = Cert} = Session0, - session_cache = Cache, session_cache_cb = CacheCb, - ssl_options = SslOpts, - connection_states = ConnectionStates0, - renegotiation = {Renegotiation, _}} = State0) -> + session = #session{own_certificate = Cert} = Session0, + session_cache = Cache, session_cache_cb = CacheCb, + ssl_options = SslOpts, + connection_states = ConnectionStates0, + renegotiation = {Renegotiation, _}} = State0) -> + Hello = dtls_handshake:client_hello(Host, Port, ConnectionStates0, SslOpts, Cache, CacheCb, Renegotiation, Cert), - {State1, Actions} = send_handshake(Hello, State0), + Version = Hello#client_hello.client_version, + HelloVersion = dtls_record:hello_version(Version, SslOpts#ssl_options.versions), + State1 = prepare_flight(State0), + {State2, Actions} = send_handshake(Hello, State1#state{negotiated_version = HelloVersion}), {Record, State} = next_record( - State1#state{session = Session0#session{session_id + State2#state{flight_state = {retransmit, ?INITIAL_RETRANSMIT_TIMEOUT}, + session = Session0#session{session_id = Hello#client_hello.session_id}}), next_event(hello, Record, State, Actions); connection(internal, #client_hello{} = Hello, #state{role = server, allow_renegotiate = true} = State) -> @@ -424,7 +481,8 @@ connection(internal, #client_hello{} = Hello, #state{role = server, allow_renego %% initiated renegotiation we will disallow many client initiated %% renegotiations immediately after each other. erlang:send_after(?WAIT_TO_ALLOW_RENEGOTIATION, self(), allow_renegotiate), - {next_state, hello, State#state{allow_renegotiate = false}, [{next_event, internal, Hello}]}; + {next_state, hello, State#state{allow_renegotiate = false, renegotiation = {true, peer}}, + [{next_event, internal, Hello}]}; connection(internal, #client_hello{}, #state{role = server, allow_renegotiate = false} = State0) -> Alert = ?ALERT_REC(?WARNING, ?NO_RENEGOTIATION), State1 = send_alert(Alert, State0), @@ -433,6 +491,9 @@ connection(internal, #client_hello{}, #state{role = server, allow_renegotiate = connection(Type, Event, State) -> ssl_connection:connection(Type, Event, State, ?MODULE). +%%TODO does this make sense for DTLS ? +downgrade(enter, _, State) -> + {keep_state, State}; downgrade(Type, Event, State) -> ssl_connection:downgrade(Type, Event, State, ?MODULE). @@ -453,24 +514,42 @@ handle_info({Protocol, _, _, _, Data}, StateName, {stop, {shutdown, own_alert}} end; handle_info({CloseTag, Socket}, StateName, - #state{socket = Socket, close_tag = CloseTag, + #state{socket = Socket, + socket_options = #socket_options{active = Active}, + protocol_buffers = #protocol_buffers{dtls_cipher_texts = CTs}, + close_tag = CloseTag, negotiated_version = Version} = State) -> %% Note that as of DTLS 1.2 (TLS 1.1), %% failure to properly close a connection no longer requires that a %% session not be resumed. This is a change from DTLS 1.0 to conform %% with widespread implementation practice. - case Version of - {254, N} when N =< 253 -> - ok; - _ -> - %% As invalidate_sessions here causes performance issues, - %% we will conform to the widespread implementation - %% practice and go aginst the spec - %%invalidate_session(Role, Host, Port, Session) - ok - end, - ssl_connection:handle_normal_shutdown(?ALERT_REC(?FATAL, ?CLOSE_NOTIFY), StateName, State), - {stop, {shutdown, transport_closed}}; + case (Active == false) andalso (CTs =/= []) of + false -> + case Version of + {254, N} when N =< 253 -> + ok; + _ -> + %% As invalidate_sessions here causes performance issues, + %% we will conform to the widespread implementation + %% practice and go aginst the spec + %%invalidate_session(Role, Host, Port, Session) + ok + end, + ssl_connection:handle_normal_shutdown(?ALERT_REC(?FATAL, ?CLOSE_NOTIFY), StateName, State), + {stop, {shutdown, transport_closed}}; + true -> + %% Fixes non-delivery of final DTLS record in {active, once}. + %% Basically allows the application the opportunity to set {active, once} again + %% and then receive the final message. + next_event(StateName, no_record, State) + end; + +handle_info(new_cookie_secret, StateName, + #state{protocol_specific = #{current_cookie_secret := Secret} = CookieInfo} = State) -> + erlang:send_after(dtls_v1:cookie_timeout(), self(), new_cookie_secret), + {next_state, StateName, State#state{protocol_specific = + CookieInfo#{current_cookie_secret => dtls_v1:cookie_secret(), + previous_cookie_secret => Secret}}}; handle_info(Msg, StateName, State) -> ssl_connection:handle_info(Msg, StateName, State). @@ -479,7 +558,7 @@ handle_call(Event, From, StateName, State) -> handle_common_event(internal, #alert{} = Alert, StateName, #state{negotiated_version = Version} = State) -> - ssl_connection:handle_own_alert(Alert, Version, StateName, State); + handle_own_alert(Alert, Version, StateName, State); %%% DTLS record protocol level handshake messages handle_common_event(internal, #ssl_tls{type = ?HANDSHAKE, fragment = Data}, @@ -498,7 +577,7 @@ handle_common_event(internal, #ssl_tls{type = ?HANDSHAKE, State#state{unprocessed_handshake_events = unprocessed_events(Events)}, Events} end catch throw:#alert{} = Alert -> - ssl_connection:handle_own_alert(Alert, Version, StateName, State0) + handle_own_alert(Alert, Version, StateName, State0) end; %%% DTLS record protocol level application data messages handle_common_event(internal, #ssl_tls{type = ?APPLICATION_DATA, fragment = Data}, StateName, State) -> @@ -513,7 +592,7 @@ handle_common_event(internal, #ssl_tls{type = ?ALERT, fragment = EncAlerts}, Sta Alerts = [_|_] -> handle_alerts(Alerts, {next_state, StateName, State}); #alert{} = Alert -> - ssl_connection:handle_own_alert(Alert, Version, StateName, State) + handle_own_alert(Alert, Version, StateName, State) end; %% Ignore unknown TLS record level protocol messages handle_common_event(internal, #ssl_tls{type = _Unknown}, StateName, State) -> @@ -565,7 +644,7 @@ handle_client_hello(#client_hello{client_version = ClientVersion} = Hello, case dtls_handshake:hello(Hello, SslOpts, {Port, Session0, Cache, CacheCb, ConnectionStates0, Cert, KeyExAlg}, Renegotiation) of #alert{} = Alert -> - ssl_connection:handle_own_alert(Alert, ClientVersion, hello, State0); + handle_own_alert(Alert, ClientVersion, hello, State0); {Version, {Type, Session}, ConnectionStates, Protocol0, ServerHelloExt, HashSign} -> Protocol = case Protocol0 of @@ -658,17 +737,36 @@ next_record(#state{unprocessed_handshake_events = N} = State) when N > 0 -> {no_record, State#state{unprocessed_handshake_events = N-1}}; next_record(#state{protocol_buffers = - #protocol_buffers{dtls_cipher_texts = [CT | Rest]} + #protocol_buffers{dtls_cipher_texts = [#ssl_tls{epoch = Epoch} = CT | Rest]} = Buffers, - connection_states = ConnStates0} = State) -> - case dtls_record:decode_cipher_text(CT, ConnStates0) of - {Plain, ConnStates} -> - {Plain, State#state{protocol_buffers = - Buffers#protocol_buffers{dtls_cipher_texts = Rest}, - connection_states = ConnStates}}; - #alert{} = Alert -> - {Alert, State} + connection_states = #{current_read := #{epoch := Epoch}} = ConnectionStates} = State) -> + CurrentRead = dtls_record:get_connection_state_by_epoch(Epoch, ConnectionStates, read), + case dtls_record:replay_detect(CT, CurrentRead) of + false -> + decode_cipher_text(State#state{connection_states = ConnectionStates}) ; + true -> + %% Ignore replayed record + next_record(State#state{protocol_buffers = + Buffers#protocol_buffers{dtls_cipher_texts = Rest}, + connection_states = ConnectionStates}) end; +next_record(#state{protocol_buffers = + #protocol_buffers{dtls_cipher_texts = [#ssl_tls{epoch = Epoch} | Rest]} + = Buffers, + connection_states = #{current_read := #{epoch := CurrentEpoch}} = ConnectionStates} = State) + when Epoch > CurrentEpoch -> + %% TODO Buffer later Epoch message, drop it for now + next_record(State#state{protocol_buffers = + Buffers#protocol_buffers{dtls_cipher_texts = Rest}, + connection_states = ConnectionStates}); +next_record(#state{protocol_buffers = + #protocol_buffers{dtls_cipher_texts = [ _ | Rest]} + = Buffers, + connection_states = ConnectionStates} = State) -> + %% Drop old epoch message + next_record(State#state{protocol_buffers = + Buffers#protocol_buffers{dtls_cipher_texts = Rest}, + connection_states = ConnectionStates}); next_record(#state{role = server, socket = {Listener, {Client, _}}, transport_cb = gen_udp} = State) -> @@ -708,36 +806,90 @@ next_event(connection = StateName, no_record, case next_record_if_active(State0) of {no_record, State} -> ssl_connection:hibernate_after(StateName, State, Actions); - {#ssl_tls{epoch = CurrentEpoch} = Record, State} -> + {#ssl_tls{epoch = CurrentEpoch, + type = ?HANDSHAKE, + version = Version} = Record, State1} -> + State = dtls_version(StateName, Version, State1), + {next_state, StateName, State, + [{next_event, internal, {protocol_record, Record}} | Actions]}; + {#ssl_tls{epoch = CurrentEpoch} = Record, State} -> {next_state, StateName, State, [{next_event, internal, {protocol_record, Record}} | Actions]}; {#ssl_tls{epoch = Epoch, type = ?HANDSHAKE, version = _Version}, State1} = _Record when Epoch == CurrentEpoch-1 -> - {State, MoreActions} = send_handshake_flight(State1, Epoch), - {next_state, StateName, State, Actions ++ MoreActions}; + {State2, MoreActions} = send_handshake_flight(State1, CurrentEpoch), + {NextRecord, State} = next_record(State2), + next_event(StateName, NextRecord, State, Actions ++ MoreActions); + %% From FLIGHT perspective CHANGE_CIPHER_SPEC is treated as a handshake + {#ssl_tls{epoch = Epoch, + type = ?CHANGE_CIPHER_SPEC, + version = _Version}, State1} = _Record when Epoch == CurrentEpoch-1 -> + {State2, MoreActions} = send_handshake_flight(State1, CurrentEpoch), + {NextRecord, State} = next_record(State2), + next_event(StateName, NextRecord, State, Actions ++ MoreActions); {#ssl_tls{epoch = _Epoch, - version = _Version}, State} -> + version = _Version}, State1} -> %% TODO maybe buffer later epoch - {next_state, StateName, State, Actions}; + {Record, State} = next_record(State1), + next_event(StateName, Record, State, Actions); {#alert{} = Alert, State} -> {next_state, StateName, State, [{next_event, internal, Alert} | Actions]} end; +next_event(connection = StateName, Record, + #state{connection_states = #{current_read := #{epoch := CurrentEpoch}}} = State0, Actions) -> + case Record of + #ssl_tls{epoch = CurrentEpoch, + type = ?HANDSHAKE, + version = Version} = Record -> + State = dtls_version(StateName, Version, State0), + {next_state, StateName, State, + [{next_event, internal, {protocol_record, Record}} | Actions]}; + #ssl_tls{epoch = CurrentEpoch} -> + {next_state, StateName, State0, [{next_event, internal, {protocol_record, Record}} | Actions]}; + #ssl_tls{epoch = Epoch, + type = ?HANDSHAKE, + version = _Version} when Epoch == CurrentEpoch-1 -> + {State1, MoreActions} = send_handshake_flight(State0, CurrentEpoch), + {NextRecord, State} = next_record(State1), + next_event(StateName, NextRecord, State, Actions ++ MoreActions); + %% From FLIGHT perspective CHANGE_CIPHER_SPEC is treated as a handshake + #ssl_tls{epoch = Epoch, + type = ?CHANGE_CIPHER_SPEC, + version = _Version} when Epoch == CurrentEpoch-1 -> + {State1, MoreActions} = send_handshake_flight(State0, CurrentEpoch), + {NextRecord, State} = next_record(State1), + next_event(StateName, NextRecord, State, Actions ++ MoreActions); + _ -> + next_event(StateName, no_record, State0, Actions) + end; next_event(StateName, Record, - #state{connection_states = #{current_read := #{epoch := CurrentEpoch}}} = State, Actions) -> + #state{connection_states = #{current_read := #{epoch := CurrentEpoch}}} = State0, Actions) -> case Record of no_record -> - {next_state, StateName, State, Actions}; - #ssl_tls{epoch = CurrentEpoch, - version = Version} = Record -> - {next_state, StateName, - dtls_version(StateName, Version, State), - [{next_event, internal, {protocol_record, Record}} | Actions]}; + {next_state, StateName, State0, Actions}; + #ssl_tls{epoch = CurrentEpoch, + version = Version} = Record -> + State = dtls_version(StateName, Version, State0), + {next_state, StateName, State, + [{next_event, internal, {protocol_record, Record}} | Actions]}; #ssl_tls{epoch = _Epoch, version = _Version} = _Record -> %% TODO maybe buffer later epoch - {next_state, StateName, State, Actions}; + {Record, State} = next_record(State0), + next_event(StateName, Record, State, Actions); #alert{} = Alert -> - {next_state, StateName, State, [{next_event, internal, Alert} | Actions]} + {next_state, StateName, State0, [{next_event, internal, Alert} | Actions]} + end. + +decode_cipher_text(#state{protocol_buffers = #protocol_buffers{dtls_cipher_texts = [ CT | Rest]} = Buffers, + connection_states = ConnStates0} = State) -> + case dtls_record:decode_cipher_text(CT, ConnStates0) of + {Plain, ConnStates} -> + {Plain, State#state{protocol_buffers = + Buffers#protocol_buffers{dtls_cipher_texts = Rest}, + connection_states = ConnStates}}; + #alert{} = Alert -> + {Alert, State} end. dtls_version(hello, Version, #state{role = server} = State) -> @@ -765,14 +917,14 @@ next_flight(Flight) -> Flight#{handshakes => [], change_cipher_spec => undefined, handshakes_after_change_cipher_spec => []}. - -start_flight(#state{transport_cb = gen_udp, - flight_state = {retransmit, Timeout}} = State) -> + +handle_flight_timer(#state{transport_cb = gen_udp, + flight_state = {retransmit, Timeout}} = State) -> start_retransmision_timer(Timeout, State); -start_flight(#state{transport_cb = gen_udp, +handle_flight_timer(#state{transport_cb = gen_udp, flight_state = connection} = State) -> {State, []}; -start_flight(State) -> +handle_flight_timer(State) -> %% No retransmision needed i.e DTLS over SCTP {State#state{flight_state = reliable}, []}. @@ -793,21 +945,15 @@ dtls_handshake_events(Packets) -> renegotiate(#state{role = client} = State, Actions) -> %% Handle same way as if server requested %% the renegotiation - Hs0 = ssl_handshake:init_handshake_history(), - {next_state, connection, State#state{tls_handshake_history = Hs0, - protocol_buffers = #protocol_buffers{}}, + %% Hs0 = ssl_handshake:init_handshake_history(), + {next_state, connection, State, [{next_event, internal, #hello_request{}} | Actions]}; -renegotiate(#state{role = server, - connection_states = CS0} = State0, Actions) -> +renegotiate(#state{role = server} = State0, Actions) -> HelloRequest = ssl_handshake:hello_request(), - CS = CS0#{write_msg_seq => 0}, - {State1, MoreActions} = send_handshake(HelloRequest, - State0#state{connection_states = - CS}), - Hs0 = ssl_handshake:init_handshake_history(), - {Record, State} = next_record(State1#state{tls_handshake_history = Hs0, - protocol_buffers = #protocol_buffers{}}), + State1 = prepare_flight(State0), + {State2, MoreActions} = send_handshake(HelloRequest, State1), + {Record, State} = next_record(State2), next_event(hello, Record, State, Actions ++ MoreActions). handle_alerts([], Result) -> @@ -823,7 +969,6 @@ retransmit_epoch(_StateName, #state{connection_states = ConnectionStates}) -> #{epoch := Epoch} = ssl_record:current_connection_state(ConnectionStates, write), Epoch. - update_handshake_history(#hello_verify_request{}, _, Hist) -> Hist; @@ -839,3 +984,54 @@ unprocessed_events(Events) -> %% process more TLS-records received on the socket. erlang:length(Events)-1. +handle_own_alert(Alert, Version, StateName, #state{transport_cb = gen_udp, + role = Role, + ssl_options = Options} = State0) -> + case ignore_alert(Alert, State0) of + {true, State} -> + log_ignore_alert(Options#ssl_options.log_alert, StateName, Alert, Role), + {next_state, StateName, State}; + {false, State} -> + ssl_connection:handle_own_alert(Alert, Version, StateName, State) + end; +handle_own_alert(Alert, Version, StateName, State) -> + ssl_connection:handle_own_alert(Alert, Version, StateName, State). + + +ignore_alert(#alert{level = ?FATAL}, #state{protocol_specific = #{ignored_alerts := N, + max_ignored_alerts := N}} = State) -> + {false, State}; +ignore_alert(#alert{level = ?FATAL} = Alert, + #state{protocol_specific = #{ignored_alerts := N} = PS} = State) -> + case is_ignore_alert(Alert) of + true -> + {true, State#state{protocol_specific = PS#{ignored_alerts => N+1}}}; + false -> + {false, State} + end; +ignore_alert(_, State) -> + {false, State}. + +%% RFC 6347 4.1.2.7. Handling Invalid Records +%% recommends to silently ignore invalid DTLS records when +%% upd is the transport. Note we do not support compression so no need +%% include ?DECOMPRESSION_FAILURE +is_ignore_alert(#alert{description = ?BAD_RECORD_MAC}) -> + true; +is_ignore_alert(#alert{description = ?RECORD_OVERFLOW}) -> + true; +is_ignore_alert(#alert{description = ?DECODE_ERROR}) -> + true; +is_ignore_alert(#alert{description = ?DECRYPT_ERROR}) -> + true; +is_ignore_alert(#alert{description = ?ILLEGAL_PARAMETER}) -> + true; +is_ignore_alert(_) -> + false. + +log_ignore_alert(true, StateName, Alert, Role) -> + Txt = ssl_alert:alert_txt(Alert), + error_logger:format("DTLS over UDP ~p: In state ~p ignored to send ALERT ~s as DoS-attack mitigation \n", + [Role, StateName, Txt]); +log_ignore_alert(false, _, _,_) -> + ok. |