From 0f782eb6377ddd1e5673c186b8b1a37edd610e4b Mon Sep 17 00:00:00 2001 From: Ingela Anderton Andin Date: Wed, 27 Apr 2016 11:44:37 +0200 Subject: ssl: Adapt DTLS to gen_statem DTLS is not in working mode yet, but the gen_statem rewrite should make completion easier. --- lib/ssl/src/dtls_connection.erl | 351 +++++++++++++++++----------------------- lib/ssl/src/dtls_record.erl | 25 ++- 2 files changed, 168 insertions(+), 208 deletions(-) (limited to 'lib/ssl') diff --git a/lib/ssl/src/dtls_connection.erl b/lib/ssl/src/dtls_connection.erl index 2c9fe5cfb5..82d6faee42 100644 --- a/lib/ssl/src/dtls_connection.erl +++ b/lib/ssl/src/dtls_connection.erl @@ -36,37 +36,38 @@ %% Internal application API %% Setup --export([start_fsm/8]). +-export([start_fsm/8, start_link/7, init/1]). %% State transition handling --export([next_record/1, next_state/4%, - %%next_state_connection/2 - ]). +-export([next_record/1, next_event/3]). %% Handshake handling --export([%%renegotiate/1, +-export([%%renegotiate/2, send_handshake/2, send_change_cipher/2]). + %% Alert and close handling --export([send_alert/2, handle_own_alert/4, %%handle_close_alert/3, - handle_normal_shutdown/3 - %%handle_unexpected_message/3, - %%alert_user/5, alert_user/8 +-export([%%send_alert/2, handle_own_alert/4, handle_close_alert/3, + handle_normal_shutdown/3 %%, close/5 + %%alert_user/6, alert_user/9 ]). %% Data handling -export([%%write_application_data/3, - read_application_data/2%%, -%% passive_receive/2, next_record_if_active/1 + read_application_data/2, + %%passive_receive/2, + next_record_if_active/1 %%, + %%handle_common_event/4 ]). -%% Called by tls_connection_sup --export([start_link/7]). +%% gen_statem state functions +-export([init/3, error/3, downgrade/3, %% Initiation and take down states + hello/3, certify/3, cipher/3, abbreviated/3, %% Handshake states + connection/3]). +%% gen_statem callbacks +-export([terminate/3, code_change/4, format_status/2]). -%% gen_fsm callbacks --export([init/1, hello/2, certify/2, cipher/2, - abbreviated/2, connection/2, handle_event/3, - handle_sync_event/4, handle_info/3, terminate/3, code_change/4]). +-define(GEN_STATEM_CB_MODE, state_functions). %%==================================================================== %% Internal application API @@ -141,75 +142,74 @@ send_change_cipher(Msg, #state{connection_states = ConnectionStates0, start_link(Role, Host, Port, Socket, Options, User, CbInfo) -> {ok, proc_lib:spawn_link(?MODULE, init, [[Role, Host, Port, Socket, Options, User, CbInfo]])}. -init([Role, Host, Port, Socket, {SSLOpts0, _} = Options, User, CbInfo]) -> +init([Role, Host, Port, Socket, Options, User, CbInfo]) -> process_flag(trap_exit, true), State0 = initial_state(Role, Host, Port, Socket, Options, User, CbInfo), - Handshake = ssl_handshake:init_handshake_history(), - TimeStamp = erlang:monotonic_time(), - try ssl_config:init(SSLOpts0, Role) of - {ok, Ref, CertDbHandle, FileRefHandle, CacheHandle, CRLDbInfo, OwnCert, Key, DHParams} -> - Session = State0#state.session, - State = State0#state{ - tls_handshake_history = Handshake, - session = Session#session{own_certificate = OwnCert, - time_stamp = TimeStamp}, - file_ref_db = FileRefHandle, - cert_db_ref = Ref, - cert_db = CertDbHandle, - crl_db = CRLDbInfo, - session_cache = CacheHandle, - private_key = Key, - diffie_hellman_params = DHParams}, - gen_fsm:enter_loop(?MODULE, [], hello, State, get_timeout(State)) + try + State = ssl_connection:ssl_config(State0#state.ssl_options, Role, State0), + gen_statem:enter_loop(?MODULE, [], ?GEN_STATEM_CB_MODE, init, State) catch throw:Error -> - gen_fsm:enter_loop(?MODULE, [], error, {Error,State0}, get_timeout(State0)) + gen_statem:enter_loop(?MODULE, [], ?GEN_STATEM_CB_MODE, error, {Error,State0}) end. %%-------------------------------------------------------------------- -%% Description:There should be one instance of this function for each -%% possible state name. Whenever a gen_fsm receives an event sent -%% using gen_fsm:send_event/2, the instance of this function with the -%% same name as the current state name StateName is called to handle -%% the event. It is also called if a timeout occurs. -%% -hello(start, #state{host = Host, port = Port, role = client, - ssl_options = SslOpts, - session = #session{own_certificate = Cert} = Session0, - session_cache = Cache, session_cache_cb = CacheCb, - transport_cb = Transport, socket = Socket, - connection_states = ConnectionStates0, - renegotiation = {Renegotiation, _}} = State0) -> +%% State functionsconnection/2 +%%-------------------------------------------------------------------- + +init({call, From}, {start, Timeout}, + #state{host = Host, port = Port, role = client, + ssl_options = SslOpts, + session = #session{own_certificate = Cert} = Session0, + transport_cb = Transport, socket = Socket, + connection_states = ConnectionStates0, + renegotiation = {Renegotiation, _}, + session_cache = Cache, + session_cache_cb = CacheCb + } = State0) -> + Timer = ssl_connection:start_or_recv_cancel_timer(Timeout, From), Hello = dtls_handshake:client_hello(Host, Port, ConnectionStates0, SslOpts, - Cache, CacheCb, Renegotiation, Cert), + Cache, CacheCb, Renegotiation, Cert), Version = Hello#client_hello.client_version, + HelloVersion = dtls_record:lowest_protocol_version(SslOpts#ssl_options.versions), Handshake0 = ssl_handshake:init_handshake_history(), {BinMsg, ConnectionStates, Handshake} = - encode_handshake(Hello, Version, ConnectionStates0, Handshake0), + encode_handshake(Hello, HelloVersion, ConnectionStates0, Handshake0), Transport:send(Socket, BinMsg), State1 = State0#state{connection_states = ConnectionStates, negotiated_version = Version, %% Requested version session = Session0#session{session_id = Hello#client_hello.session_id}, - tls_handshake_history = Handshake}, + tls_handshake_history = Handshake, + start_or_recv_from = From, + timer = Timer}, {Record, State} = next_record(State1), - next_state(hello, hello, Record, State); - -hello(Hello = #client_hello{client_version = ClientVersion}, - State = #state{connection_states = ConnectionStates0, - port = Port, session = #session{own_certificate = Cert} = Session0, - renegotiation = {Renegotiation, _}, - session_cache = Cache, - session_cache_cb = CacheCb, - ssl_options = SslOpts}) -> + next_event(hello, Record, State); +init(Type, Event, State) -> + ssl_connection:init(Type, Event, State, ?MODULE). + +error({call, From}, {start, _Timeout}, {Error, State}) -> + {stop_and_reply, normal, {reply, From, {error, Error}}, State}; +error({call, From}, Msg, State) -> + handle_call(Msg, From, error, State); +error(_, _, _) -> + {keep_state_and_data, [postpone]}. + +hello(internal, #client_hello{client_version = ClientVersion} = Hello, + #state{connection_states = ConnectionStates0, + port = Port, session = #session{own_certificate = Cert} = Session0, + renegotiation = {Renegotiation, _}, + session_cache = Cache, + session_cache_cb = CacheCb, + ssl_options = SslOpts} = State) -> case dtls_handshake:hello(Hello, SslOpts, {Port, Session0, Cache, CacheCb, ConnectionStates0, Cert}, Renegotiation) of {Version, {Type, Session}, ConnectionStates, #hello_extensions{ec_point_formats = EcPointFormats, elliptic_curves = EllipticCurves} = ServerHelloExt, HashSign} -> - ssl_connection:hello({common_client_hello, Type, ServerHelloExt, HashSign}, + ssl_connection:hello(internal, {common_client_hello, Type, ServerHelloExt, HashSign}, State#state{connection_states = ConnectionStates, negotiated_version = Version, session = Session, @@ -217,7 +217,7 @@ hello(Hello = #client_hello{client_version = ClientVersion}, #alert{} = Alert -> handle_own_alert(Alert, ClientVersion, hello, State) end; -hello(Hello, +hello(internal, Hello, #state{connection_states = ConnectionStates0, negotiated_version = ReqVersion, role = client, @@ -230,20 +230,30 @@ hello(Hello, ssl_connection:handle_session(Hello, Version, NewId, ConnectionStates, ProtoExt, Protocol, State) end; - -hello(Msg, State) -> - ssl_connection:hello(Msg, State, ?MODULE). - -abbreviated(Msg, State) -> - ssl_connection:abbreviated(Msg, State, ?MODULE). - -certify(Msg, State) -> - ssl_connection:certify(Msg, State, ?MODULE). - -cipher(Msg, State) -> - ssl_connection:cipher(Msg, State, ?MODULE). - -connection(#hello_request{}, #state{host = Host, port = Port, +hello(info, Event, State) -> + handle_info(Event, hello, State); + +hello(Type, Event, State) -> + ssl_connection:hello(Type, Event, State, ?MODULE). + +abbreviated(info, Event, State) -> + handle_info(Event, abbreviated, State); +abbreviated(Type, Event, State) -> + ssl_connection:abbreviated(Type, Event, State, ?MODULE). + +certify(info, Event, State) -> + handle_info(Event, certify, State); +certify(Type, Event, State) -> + ssl_connection:certify(Type, Event, State, ?MODULE). + +cipher(info, Event, State) -> + handle_info(Event, cipher, State); +cipher(Type, Event, State) -> + ssl_connection:cipher(Type, Event, State, ?MODULE). + +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, @@ -257,40 +267,30 @@ connection(#hello_request{}, #state{host = Host, port = Port, next_record( State1#state{session = Session0#session{session_id = Hello#client_hello.session_id}}), - next_state(connection, hello, Record, State); + next_event(hello, Record, State); -connection(#client_hello{} = Hello, #state{role = server, allow_renegotiate = true} = State) -> +connection(internal, #client_hello{} = Hello, #state{role = server, allow_renegotiate = true} = State) -> %% Mitigate Computational DoS attack %% http://www.educatedguesswork.org/2011/10/ssltls_and_computational_dos.html %% http://www.thc.org/thc-ssl-dos/ Rather than disabling client %% initiated renegotiation we will disallow many client initiated %% renegotiations immediately after each other. erlang:send_after(?WAIT_TO_ALLOW_RENEGOTIATION, self(), allow_renegotiate), - hello(Hello, State#state{allow_renegotiate = false}); + {next_state, hello, State#state{allow_renegotiate = false}, [{next_event, internal, Hello}]}; + -connection(#client_hello{}, #state{role = server, allow_renegotiate = false} = State0) -> +connection(internal, #client_hello{}, #state{role = server, allow_renegotiate = false} = State0) -> Alert = ?ALERT_REC(?WARNING, ?NO_RENEGOTIATION), - State = send_alert(Alert, State0), - next_state_connection(connection, State); + State1 = send_alert(Alert, State0), + {Record, State} = ssl_connection:prepare_connection(State1, ?MODULE), + next_event(connection, Record, State); -connection(Msg, State) -> - ssl_connection:connection(Msg, State, tls_connection). +connection(Type, Event, State) -> + ssl_connection:connection(Type, Event, State, ?MODULE). -%%-------------------------------------------------------------------- -%% Description: Whenever a gen_fsm receives an event sent using -%% gen_fsm:send_all_state_event/2, this function is called to handle -%% the event. Not currently used! -%%-------------------------------------------------------------------- -handle_event(_Event, StateName, State) -> - {next_state, StateName, State, get_timeout(State)}. +downgrade(Type, Event, State) -> + ssl_connection:downgrade(Type, Event, State, ?MODULE). -%%-------------------------------------------------------------------- -%% Description: Whenever a gen_fsm receives an event sent using -%% gen_fsm:sync_send_all_state_event/2,3, this function is called to handle -%% the event. -%%-------------------------------------------------------------------- -handle_sync_event(Event, From, StateName, State) -> - ssl_connection:handle_sync_event(Event, From, StateName, State). %%-------------------------------------------------------------------- %% Description: This function is called by a gen_fsm when it receives any @@ -301,26 +301,25 @@ handle_sync_event(Event, From, StateName, State) -> %% raw data from socket, unpack records handle_info({Protocol, _, Data}, StateName, #state{data_tag = Protocol} = State0) -> - %% Simplify for now to avoid dialzer warnings before implementation is compleate - %% case next_tls_record(Data, State0) of - %% {Record, State} -> - %% next_state(StateName, StateName, Record, State); - %% #alert{} = Alert -> - %% handle_normal_shutdown(Alert, StateName, State0), - %% {stop, {shutdown, own_alert}, State0} - %% end; - {Record, State} = next_tls_record(Data, State0), - next_state(StateName, StateName, Record, State); - + case next_tls_record(Data, State0) of + {Record, State} -> + next_event(StateName, Record, State); + #alert{} = Alert -> + handle_normal_shutdown(Alert, StateName, State0), + {stop, {shutdown, own_alert}} + end; handle_info({CloseTag, Socket}, StateName, #state{socket = Socket, close_tag = CloseTag, negotiated_version = _Version} = State) -> handle_normal_shutdown(?ALERT_REC(?FATAL, ?CLOSE_NOTIFY), StateName, State), - {stop, {shutdown, transport_closed}, State}; + {stop, {shutdown, transport_closed}}; handle_info(Msg, StateName, State) -> ssl_connection:handle_info(Msg, StateName, State). +handle_call(Event, From, StateName, State) -> + ssl_connection:handle_call(Event, From, StateName, State, ?MODULE). + %%-------------------------------------------------------------------- %% Description:This function is called by a gen_fsm when it is about %% to terminate. It should be the opposite of Module:init/1 and do any @@ -335,7 +334,10 @@ terminate(Reason, StateName, State) -> %% Description: Convert process state when code is changed %%-------------------------------------------------------------------- code_change(_OldVsn, StateName, State, _Extra) -> - {ok, StateName, State}. + {?GEN_STATEM_CB_MODE, StateName, State}. + +format_status(Type, Data) -> + ssl_connection:format_status(Type, Data). %%-------------------------------------------------------------------- %%% Internal functions @@ -372,96 +374,28 @@ next_record(#state{socket = Socket, next_record(State) -> {no_record, State}. -next_state(Current,_, #alert{} = Alert, #state{negotiated_version = Version} = State) -> - handle_own_alert(Alert, Version, Current, State); - -next_state(_,Next, no_record, State) -> - {next_state, Next, State, get_timeout(State)}; - -%% next_state(_,Next, #ssl_tls{type = ?ALERT, fragment = EncAlerts}, State) -> -%% Alerts = decode_alerts(EncAlerts), -%% handle_alerts(Alerts, {next_state, Next, State, get_timeout(State)}); - -next_state(Current, Next, #ssl_tls{type = ?HANDSHAKE, fragment = Data}, - State0 = #state{protocol_buffers = - #protocol_buffers{dtls_handshake_buffer = Buf0} = Buffers, - negotiated_version = Version}) -> - Handle = - fun({#hello_request{} = Packet, _}, {next_state, connection = SName, State}) -> - %% This message should not be included in handshake - %% message hashes. Starts new handshake (renegotiation) - Hs0 = ssl_handshake:init_handshake_history(), - ?MODULE:SName(Packet, State#state{tls_handshake_history=Hs0, - renegotiation = {true, peer}}); - ({#hello_request{} = Packet, _}, {next_state, SName, State}) -> - %% This message should not be included in handshake - %% message hashes. Already in negotiation so it will be ignored! - ?MODULE:SName(Packet, State); - ({#client_hello{} = Packet, Raw}, {next_state, connection = SName, State}) -> - Version = Packet#client_hello.client_version, - Hs0 = ssl_handshake:init_handshake_history(), - Hs1 = ssl_handshake:update_handshake_history(Hs0, Raw), - ?MODULE:SName(Packet, State#state{tls_handshake_history=Hs1, - renegotiation = {true, peer}}); - ({Packet, Raw}, {next_state, SName, State = #state{tls_handshake_history=Hs0}}) -> - Hs1 = ssl_handshake:update_handshake_history(Hs0, Raw), - ?MODULE:SName(Packet, State#state{tls_handshake_history=Hs1}); - (_, StopState) -> StopState - end, - try - {Packets, Buf} = tls_handshake:get_tls_handshake(Version,Data,Buf0), - State = State0#state{protocol_buffers = - Buffers#protocol_buffers{dtls_packets = Packets, - dtls_handshake_buffer = Buf}}, - handle_dtls_handshake(Handle, Next, State) - catch throw:#alert{} = Alert -> - handle_own_alert(Alert, Version, Current, State0) - end; -next_state(_, StateName, #ssl_tls{type = ?APPLICATION_DATA, fragment = Data}, State0) -> - %% Simplify for now to avoid dialzer warnings before implementation is compleate - %% case read_application_data(Data, State0) of - %% Stop = {stop,_,_} -> - %% Stop; - %% {Record, State} -> - %% next_state(StateName, StateName, Record, State) - %% end; - {Record, State} = read_application_data(Data, State0), - next_state(StateName, StateName, Record, State); - -next_state(Current, Next, #ssl_tls{type = ?CHANGE_CIPHER_SPEC, fragment = <<1>>} = - _ChangeCipher, - #state{connection_states = ConnectionStates0} = State0) -> - ConnectionStates1 = - ssl_record:activate_pending_connection_state(ConnectionStates0, read), - {Record, State} = next_record(State0#state{connection_states = ConnectionStates1}), - next_state(Current, Next, Record, State); -next_state(Current, Next, #ssl_tls{type = _Unknown}, State0) -> - %% Ignore unknown type - {Record, State} = next_record(State0), - next_state(Current, Next, Record, State). - -handle_dtls_handshake(Handle, StateName, - #state{protocol_buffers = - #protocol_buffers{dtls_packets = [Packet]} = Buffers} = State) -> - FsmReturn = {next_state, StateName, State#state{protocol_buffers = - Buffers#protocol_buffers{dtls_packets = []}}}, - Handle(Packet, FsmReturn); - -handle_dtls_handshake(Handle, StateName, - #state{protocol_buffers = - #protocol_buffers{dtls_packets = [Packet | Packets]} = Buffers} = - State0) -> - FsmReturn = {next_state, StateName, State0#state{protocol_buffers = - Buffers#protocol_buffers{dtls_packets = - Packets}}}, - case Handle(Packet, FsmReturn) of - {next_state, NextStateName, State, _Timeout} -> - handle_dtls_handshake(Handle, NextStateName, State); - {stop, _,_} = Stop -> - Stop - end. +next_event(StateName, Record, State) -> + next_event(StateName, Record, State, []). +next_event(connection = StateName, no_record, State0, Actions) -> + case next_record_if_active(State0) of + {no_record, State} -> + ssl_connection:hibernate_after(StateName, State, Actions); + {#ssl_tls{} = Record, State} -> + {next_state, StateName, State, [{next_event, internal, {dtls_record, Record}} | Actions]}; + {#alert{} = Alert, State} -> + {next_state, StateName, State, [{next_event, internal, Alert} | Actions]} + end; +next_event(StateName, Record, State, Actions) -> + case Record of + no_record -> + {next_state, StateName, State, Actions}; + #ssl_tls{} = Record -> + {next_state, StateName, State, [{next_event, internal, {dtls_record, Record}} | Actions]}; + #alert{} = Alert -> + {next_state, StateName, State, [{next_event, internal, Alert} | Actions]} + end. send_flight(Fragments, #state{transport_cb = Transport, socket = Socket, protocol_buffers = _PBuffers} = State) -> @@ -518,16 +452,19 @@ initial_state(Role, Host, Port, Socket, {SSLOptions, SocketOptions}, User, }. read_application_data(_,State) -> {#ssl_tls{fragment = <<"place holder">>}, State}. - + +next_tls_record(<<>>, _State) -> + #alert{}; %% Place holder next_tls_record(_, State) -> {#ssl_tls{fragment = <<"place holder">>}, State}. -get_timeout(_) -> %% Place holder - infinity. - -next_state_connection(_, State) -> %% Place holder - {next_state, connection, State, get_timeout(State)}. - sequence(_) -> %%TODO real imp 1. +next_record_if_active(State = + #state{socket_options = + #socket_options{active = false}}) -> + {no_record ,State}; + +next_record_if_active(State) -> + next_record(State). diff --git a/lib/ssl/src/dtls_record.erl b/lib/ssl/src/dtls_record.erl index 2530d66052..e79e1cede0 100644 --- a/lib/ssl/src/dtls_record.erl +++ b/lib/ssl/src/dtls_record.erl @@ -39,7 +39,7 @@ -export([encode_plain_text/4, encode_handshake/3, encode_change_cipher_spec/2]). %% Protocol version handling --export([protocol_version/1, lowest_protocol_version/2, +-export([protocol_version/1, lowest_protocol_version/2, lowest_protocol_version/1, highest_protocol_version/1, supported_protocol_versions/0, is_acceptable_version/2]). @@ -254,6 +254,18 @@ lowest_protocol_version(Version = {M,_}, {N, _}) when M > N -> Version; lowest_protocol_version(_,Version) -> Version. + +%%-------------------------------------------------------------------- +-spec lowest_protocol_version([dtls_version()]) -> dtls_version(). +%% +%% Description: Lowest protocol version present in a list +%%-------------------------------------------------------------------- +lowest_protocol_version([]) -> + lowest_protocol_version(); +lowest_protocol_version(Versions) -> + [Ver | Vers] = Versions, + lowest_list_protocol_version(Ver, Vers). + %%-------------------------------------------------------------------- -spec highest_protocol_version([dtls_version()]) -> dtls_version(). %% @@ -302,6 +314,12 @@ supported_protocol_versions([]) -> supported_protocol_versions([_|_] = Vsns) -> Vsns. +%% highest_protocol_version() -> +%% highest_protocol_version(supported_protocol_versions()). + +lowest_protocol_version() -> + lowest_protocol_version(supported_protocol_versions()). + supported_connection_protocol_versions([]) -> ?ALL_DATAGRAM_SUPPORTED_VERSIONS. @@ -421,3 +439,8 @@ mac_hash(Version, MacAlg, MacSecret, SeqNo, Type, Length, Fragment) -> calc_aad(Type, {MajVer, MinVer}, Epoch, SeqNo) -> NewSeq = (Epoch bsl 48) + SeqNo, <>. + +lowest_list_protocol_version(Ver, []) -> + Ver; +lowest_list_protocol_version(Ver1, [Ver2 | Rest]) -> + lowest_list_protocol_version(lowest_protocol_version(Ver1, Ver2), Rest). -- cgit v1.2.3