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-rw-r--r--lib/ssl/src/dtls_connection.erl225
1 files changed, 188 insertions, 37 deletions
diff --git a/lib/ssl/src/dtls_connection.erl b/lib/ssl/src/dtls_connection.erl
index 14d802085f..ff3e69bae5 100644
--- a/lib/ssl/src/dtls_connection.erl
+++ b/lib/ssl/src/dtls_connection.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 2013-2016. All Rights Reserved.
+%% Copyright Ericsson AB 2013-2017. 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.
@@ -48,12 +48,12 @@
select_sni_extension/1]).
%% 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
@@ -115,7 +115,7 @@ send_handshake_flight(#state{socket = Socket,
{Encoded, ConnectionStates} =
encode_handshake_flight(lists:reverse(Flight), Version, 1400, Epoch, ConnectionStates0),
send(Transport, Socket, Encoded),
- start_flight(State0#state{connection_states = ConnectionStates});
+ {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) ->
@@ -203,6 +203,14 @@ select_sni_extension(_) ->
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 +238,14 @@ 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,
@@ -266,7 +276,9 @@ init({call, _} = Type, Event, #state{role = server, transport_cb = gen_udp} = St
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 => <<>>}},
+ previous_cookie_secret => <<>>,
+ ignored_alerts => 0,
+ max_ignored_alerts => 10}},
?MODULE),
erlang:send_after(dtls_v1:cookie_timeout(), self(), new_cookie_secret),
Result;
@@ -277,6 +289,8 @@ init({call, _} = Type, Event, #state{role = server} = State) ->
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) ->
@@ -290,6 +304,11 @@ 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,
@@ -297,7 +316,13 @@ hello(internal, #client_hello{cookie = <<>>,
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),
+ %% 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),
@@ -351,7 +376,7 @@ 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)
@@ -369,6 +394,9 @@ 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,
@@ -386,6 +414,9 @@ 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) ->
@@ -395,6 +426,9 @@ 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,
@@ -412,6 +446,8 @@ 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,
@@ -444,6 +480,9 @@ 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).
@@ -509,7 +548,7 @@ 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},
@@ -528,7 +567,7 @@ 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) ->
@@ -543,7 +582,7 @@ 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) ->
@@ -595,7 +634,7 @@ 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
@@ -688,17 +727,36 @@ 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) ->
@@ -743,31 +801,73 @@ next_event(connection = StateName, no_record,
{#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} ->
+ {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};
+ {next_state, StateName, State0, Actions};
#ssl_tls{epoch = CurrentEpoch,
version = Version} = Record ->
{next_state, StateName,
- dtls_version(StateName, Version, State),
+ dtls_version(StateName, Version, State0),
[{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) ->
@@ -796,13 +896,13 @@ next_flight(Flight) ->
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}, []}.
@@ -869,3 +969,54 @@ 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.
generated by cgit v1.2.3 (git 2.25.1) at 2024-08-03 15:08:09 +0000