%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2007-2018. 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.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%%
%%----------------------------------------------------------------------
%% Purpose: Handles an ssl connection, e.i. both the setup
%% e.i. SSL-Handshake, SSL-Alert and SSL-Cipher protocols and delivering
%% data to the application. All data on the connectinon is received and
%% sent according to the SSL-record protocol.
%%----------------------------------------------------------------------
-module(tls_connection).
-behaviour(gen_statem).
-include("tls_connection.hrl").
-include("tls_handshake.hrl").
-include("ssl_alert.hrl").
-include("tls_record.hrl").
-include("ssl_cipher.hrl").
-include("ssl_api.hrl").
-include("ssl_internal.hrl").
-include("ssl_srp.hrl").
-include_lib("public_key/include/public_key.hrl").
%% Internal application API
%% Setup
-export([start_fsm/8, start_link/8, init/1, pids/1]).
%% State transition handling
-export([next_event/3, next_event/4,
handle_protocol_record/3]).
%% Handshake handling
-export([renegotiation/2, renegotiate/2, send_handshake/2,
queue_handshake/2, queue_change_cipher/2,
reinit/1, reinit_handshake_data/1, select_sni_extension/1,
empty_connection_state/2]).
%% Alert and close handling
-export([send_alert/2, send_alert_in_connection/2,
send_sync_alert/2,
encode_alert/3, close/5, protocol_name/0]).
%% Data handling
-export([encode_data/3, next_record/1,
send/3, socket/5, setopts/3, getopts/3]).
%% gen_statem state functions
-export([init/3, error/3, downgrade/3, %% Initiation and take down states
hello/3, user_hello/3, certify/3, cipher/3, abbreviated/3, %% Handshake states
connection/3]).
%% gen_statem callbacks
-export([callback_mode/0, terminate/3, code_change/4, format_status/2]).
-define(DIST_CNTRL_SPAWN_OPTS, [{priority, max}]).
%%====================================================================
%% Internal application API
%%====================================================================
%%====================================================================
%% Setup
%%====================================================================
start_fsm(Role, Host, Port, Socket, {#ssl_options{erl_dist = false},_, Tracker} = Opts,
User, {CbModule, _,_, _} = CbInfo,
Timeout) ->
try
{ok, Sender} = tls_sender:start(),
{ok, Pid} = tls_connection_sup:start_child([Role, Sender, Host, Port, Socket,
Opts, User, CbInfo]),
{ok, SslSocket} = ssl_connection:socket_control(?MODULE, Socket, [Pid, Sender], CbModule, Tracker),
ssl_connection:handshake(SslSocket, Timeout)
catch
error:{badmatch, {error, _} = Error} ->
Error
end;
start_fsm(Role, Host, Port, Socket, {#ssl_options{erl_dist = true},_, Tracker} = Opts,
User, {CbModule, _,_, _} = CbInfo,
Timeout) ->
try
{ok, Sender} = tls_sender:start([{spawn_opt, ?DIST_CNTRL_SPAWN_OPTS}]),
{ok, Pid} = tls_connection_sup:start_child_dist([Role, Sender, Host, Port, Socket,
Opts, User, CbInfo]),
{ok, SslSocket} = ssl_connection:socket_control(?MODULE, Socket, [Pid, Sender], CbModule, Tracker),
ssl_connection:handshake(SslSocket, Timeout)
catch
error:{badmatch, {error, _} = Error} ->
Error
end.
%%--------------------------------------------------------------------
-spec start_link(atom(), pid(), host(), inet:port_number(), port(), list(), pid(), tuple()) ->
{ok, pid()} | ignore | {error, reason()}.
%%
%% Description: Creates a gen_statem process which calls Module:init/1 to
%% initialize.
%%--------------------------------------------------------------------
start_link(Role, Sender, Host, Port, Socket, Options, User, CbInfo) ->
{ok, proc_lib:spawn_link(?MODULE, init, [[Role, Sender, Host, Port, Socket, Options, User, CbInfo]])}.
init([Role, Sender, Host, Port, Socket, {SslOpts, _, _} = Options, User, CbInfo]) ->
process_flag(trap_exit, true),
link(Sender),
case SslOpts#ssl_options.erl_dist of
true ->
process_flag(priority, max);
_ ->
ok
end,
State0 = #state{protocol_specific = Map} = initial_state(Role, Sender,
Host, Port, Socket, Options, User, CbInfo),
try
State = ssl_connection:ssl_config(State0#state.ssl_options, Role, State0),
initialize_tls_sender(State),
gen_statem:enter_loop(?MODULE, [], init, State)
catch throw:Error ->
EState = State0#state{protocol_specific = Map#{error => Error}},
gen_statem:enter_loop(?MODULE, [], error, EState)
end.
pids(#state{protocol_specific = #{sender := Sender}}) ->
[self(), Sender].
%%====================================================================
%% State transition handling
%%====================================================================
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{tls_packets = [], tls_cipher_texts = [CT | Rest]}
= Buffers,
connection_states = ConnStates0,
ssl_options = #ssl_options{padding_check = Check}} = State) ->
case tls_record:decode_cipher_text(CT, ConnStates0, Check) of
{Plain, ConnStates} ->
{Plain, State#state{protocol_buffers =
Buffers#protocol_buffers{tls_cipher_texts = Rest},
connection_states = ConnStates}};
#alert{} = Alert ->
{Alert, State}
end;
next_record(#state{protocol_buffers = #protocol_buffers{tls_packets = [], tls_cipher_texts = []},
protocol_specific = #{active_n_toggle := true, active_n := N} = ProtocolSpec,
static_env = #static_env{socket = Socket,
close_tag = CloseTag,
transport_cb = Transport}
} = State) ->
case tls_socket:setopts(Transport, Socket, [{active, N}]) of
ok ->
{no_record, State#state{protocol_specific = ProtocolSpec#{active_n_toggle => false}}};
_ ->
self() ! {CloseTag, Socket},
{no_record, State}
end;
next_record(State) ->
{no_record, State}.
next_event(StateName, Record, State) ->
next_event(StateName, Record, State, []).
next_event(StateName, no_record, State0, Actions) ->
case next_record(State0) of
{no_record, State} ->
{next_state, StateName, State, Actions};
{#ssl_tls{} = Record, State} ->
{next_state, StateName, State, [{next_event, internal, {protocol_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, {protocol_record, Record}} | Actions]};
#alert{} = Alert ->
{next_state, StateName, State, [{next_event, internal, Alert} | Actions]}
end.
%%% TLS record protocol level application data messages
handle_protocol_record(#ssl_tls{type = ?APPLICATION_DATA, fragment = Data}, StateName, State0) ->
case ssl_connection:read_application_data(Data, State0) of
{stop, _, _} = Stop->
Stop;
{Record, State1} ->
{next_state, StateName, State, Actions} = next_event(StateName, Record, State1),
ssl_connection:hibernate_after(StateName, State, Actions)
end;
%%% TLS record protocol level handshake messages
handle_protocol_record(#ssl_tls{type = ?HANDSHAKE, fragment = Data},
StateName, #state{protocol_buffers =
#protocol_buffers{tls_handshake_buffer = Buf0} = Buffers,
negotiated_version = Version,
ssl_options = Options} = State0) ->
try
{Packets, Buf} = tls_handshake:get_tls_handshake(Version,Data,Buf0, Options),
State =
State0#state{protocol_buffers =
Buffers#protocol_buffers{tls_handshake_buffer = Buf}},
case Packets of
[] ->
assert_buffer_sanity(Buf, Options),
next_event(StateName, no_record, State);
_ ->
Events = tls_handshake_events(Packets),
case StateName of
connection ->
ssl_connection:hibernate_after(StateName, State, Events);
_ ->
{next_state, StateName,
State#state{unprocessed_handshake_events = unprocessed_events(Events)}, Events}
end
end
catch throw:#alert{} = Alert ->
ssl_connection:handle_own_alert(Alert, Version, StateName, State0)
end;
%%% TLS record protocol level change cipher messages
handle_protocol_record(#ssl_tls{type = ?CHANGE_CIPHER_SPEC, fragment = Data}, StateName, State) ->
{next_state, StateName, State, [{next_event, internal, #change_cipher_spec{type = Data}}]};
%%% TLS record protocol level Alert messages
handle_protocol_record(#ssl_tls{type = ?ALERT, fragment = EncAlerts}, StateName,
#state{negotiated_version = Version} = State) ->
try decode_alerts(EncAlerts) of
Alerts = [_|_] ->
handle_alerts(Alerts, {next_state, StateName, State});
[] ->
ssl_connection:handle_own_alert(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, empty_alert),
Version, StateName, State);
#alert{} = Alert ->
ssl_connection:handle_own_alert(Alert, Version, StateName, State)
catch
_:_ ->
ssl_connection:handle_own_alert(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, alert_decode_error),
Version, StateName, State)
end;
%% Ignore unknown TLS record level protocol messages
handle_protocol_record(#ssl_tls{type = _Unknown}, StateName, State) ->
{next_state, StateName, State, []}.
%%====================================================================
%% Handshake handling
%%====================================================================
renegotiation(Pid, WriteState) ->
gen_statem:call(Pid, {user_renegotiate, WriteState}).
renegotiate(#state{static_env = #static_env{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},
[{next_event, internal, #hello_request{}} | Actions]};
renegotiate(#state{static_env = #static_env{role = server,
socket = Socket,
transport_cb = Transport},
negotiated_version = Version,
connection_states = ConnectionStates0} = State0, Actions) ->
HelloRequest = ssl_handshake:hello_request(),
Frag = tls_handshake:encode_handshake(HelloRequest, Version),
Hs0 = ssl_handshake:init_handshake_history(),
{BinMsg, ConnectionStates} =
tls_record:encode_handshake(Frag, Version, ConnectionStates0),
send(Transport, Socket, BinMsg),
State = State0#state{connection_states =
ConnectionStates,
tls_handshake_history = Hs0},
next_event(hello, no_record, State, Actions).
send_handshake(Handshake, State) ->
send_handshake_flight(queue_handshake(Handshake, State)).
queue_handshake(Handshake, #state{negotiated_version = Version,
tls_handshake_history = Hist0,
flight_buffer = Flight0,
connection_states = ConnectionStates0} = State0) ->
{BinHandshake, ConnectionStates, Hist} =
encode_handshake(Handshake, Version, ConnectionStates0, Hist0),
State0#state{connection_states = ConnectionStates,
tls_handshake_history = Hist,
flight_buffer = Flight0 ++ [BinHandshake]}.
send_handshake_flight(#state{static_env = #static_env{socket = Socket,
transport_cb = Transport},
flight_buffer = Flight} = State0) ->
send(Transport, Socket, Flight),
{State0#state{flight_buffer = []}, []}.
queue_change_cipher(Msg, #state{negotiated_version = Version,
flight_buffer = Flight0,
connection_states = ConnectionStates0} = State0) ->
{BinChangeCipher, ConnectionStates} =
encode_change_cipher(Msg, Version, ConnectionStates0),
State0#state{connection_states = ConnectionStates,
flight_buffer = Flight0 ++ [BinChangeCipher]}.
reinit(#state{protocol_specific = #{sender := Sender},
negotiated_version = Version,
connection_states = #{current_write := Write}} = State) ->
tls_sender:update_connection_state(Sender, Write, Version),
reinit_handshake_data(State).
reinit_handshake_data(State) ->
%% premaster_secret, public_key_info and tls_handshake_info
%% are only needed during the handshake phase.
%% To reduce memory foot print of a connection reinitialize them.
State#state{
premaster_secret = undefined,
public_key_info = undefined,
tls_handshake_history = ssl_handshake:init_handshake_history()
}.
select_sni_extension(#client_hello{extensions = HelloExtensions}) ->
HelloExtensions#hello_extensions.sni;
select_sni_extension(_) ->
undefined.
empty_connection_state(ConnectionEnd, BeastMitigation) ->
ssl_record:empty_connection_state(ConnectionEnd, BeastMitigation).
%%====================================================================
%% Alert and close handling
%%====================================================================
%%--------------------------------------------------------------------
-spec encode_alert(#alert{}, ssl_record:ssl_version(), ssl_record:connection_states()) ->
{iolist(), ssl_record:connection_states()}.
%%
%% Description: Encodes an alert
%%--------------------------------------------------------------------
encode_alert(#alert{} = Alert, Version, ConnectionStates) ->
tls_record:encode_alert_record(Alert, Version, ConnectionStates).
send_alert(Alert, #state{negotiated_version = Version,
static_env = #static_env{socket = Socket,
transport_cb = Transport},
connection_states = ConnectionStates0} = StateData0) ->
{BinMsg, ConnectionStates} =
encode_alert(Alert, Version, ConnectionStates0),
send(Transport, Socket, BinMsg),
StateData0#state{connection_states = ConnectionStates}.
%% If an ALERT sent in the connection state, should cause the TLS
%% connection to end, we need to synchronize with the tls_sender
%% process so that the ALERT if possible (that is the tls_sender process is
%% not blocked) is sent before the connection process terminates and
%% thereby closes the transport socket.
send_alert_in_connection(#alert{level = ?FATAL} = Alert, State) ->
send_sync_alert(Alert, State);
send_alert_in_connection(#alert{description = ?CLOSE_NOTIFY} = Alert, State) ->
send_sync_alert(Alert, State);
send_alert_in_connection(Alert,
#state{protocol_specific = #{sender := Sender}}) ->
tls_sender:send_alert(Sender, Alert).
send_sync_alert(
Alert, #state{protocol_specific = #{sender := Sender}} = State) ->
try tls_sender:send_and_ack_alert(Sender, Alert)
catch
_:_ ->
throw({stop, {shutdown, own_alert}, State})
end.
%% User closes or recursive call!
close({close, Timeout}, Socket, Transport = gen_tcp, _,_) ->
tls_socket:setopts(Transport, Socket, [{active, false}]),
Transport:shutdown(Socket, write),
_ = Transport:recv(Socket, 0, Timeout),
ok;
%% Peer closed socket
close({shutdown, transport_closed}, Socket, Transport = gen_tcp, ConnectionStates, Check) ->
close({close, 0}, Socket, Transport, ConnectionStates, Check);
%% We generate fatal alert
close({shutdown, own_alert}, Socket, Transport = gen_tcp, ConnectionStates, Check) ->
%% Standard trick to try to make sure all
%% data sent to the tcp port is really delivered to the
%% peer application before tcp port is closed so that the peer will
%% get the correct TLS alert message and not only a transport close.
%% Will return when other side has closed or after timout millisec
%% e.g. we do not want to hang if something goes wrong
%% with the network but we want to maximise the odds that
%% peer application gets all data sent on the tcp connection.
close({close, ?DEFAULT_TIMEOUT}, Socket, Transport, ConnectionStates, Check);
close(downgrade, _,_,_,_) ->
ok;
%% Other
close(_, Socket, Transport, _,_) ->
Transport:close(Socket).
protocol_name() ->
"TLS".
%%====================================================================
%% Data handling
%%====================================================================
encode_data(Data, Version, ConnectionStates0)->
tls_record:encode_data(Data, Version, ConnectionStates0).
send(Transport, Socket, Data) ->
tls_socket:send(Transport, Socket, Data).
socket(Pids, Transport, Socket, Connection, Tracker) ->
tls_socket:socket(Pids, Transport, Socket, Connection, Tracker).
setopts(Transport, Socket, Other) ->
tls_socket:setopts(Transport, Socket, Other).
getopts(Transport, Socket, Tag) ->
tls_socket:getopts(Transport, Socket, Tag).
%%--------------------------------------------------------------------
%% State functions
%%--------------------------------------------------------------------
%%--------------------------------------------------------------------
-spec init(gen_statem:event_type(),
{start, timeout()} | term(), #state{}) ->
gen_statem:state_function_result().
%%--------------------------------------------------------------------
init({call, From}, {start, Timeout},
#state{static_env = #static_env{role = client,
host = Host,
port = Port,
transport_cb = Transport,
socket = Socket,
session_cache = Cache,
session_cache_cb = CacheCb},
ssl_options = SslOpts,
session = #session{own_certificate = Cert} = Session0,
connection_states = ConnectionStates0,
renegotiation = {Renegotiation, _}
} = State0) ->
Timer = ssl_connection:start_or_recv_cancel_timer(Timeout, From),
Hello = tls_handshake:client_hello(Host, Port, ConnectionStates0, SslOpts,
Cache, CacheCb, Renegotiation, Cert),
Version = Hello#client_hello.client_version,
HelloVersion = tls_record:hello_version(Version, SslOpts#ssl_options.versions),
Handshake0 = ssl_handshake:init_handshake_history(),
{BinMsg, ConnectionStates, Handshake} =
encode_handshake(Hello, HelloVersion, ConnectionStates0, Handshake0),
send(Transport, Socket, BinMsg),
State = State0#state{connection_states = ConnectionStates,
negotiated_version = Version, %% Requested version
session =
Session0#session{session_id = Hello#client_hello.session_id},
tls_handshake_history = Handshake,
start_or_recv_from = From,
timer = Timer},
next_event(hello, no_record, State);
init(Type, Event, State) ->
gen_handshake(?FUNCTION_NAME, Type, Event, State).
%%--------------------------------------------------------------------
-spec error(gen_statem:event_type(),
{start, timeout()} | term(), #state{}) ->
gen_statem:state_function_result().
%%--------------------------------------------------------------------
error({call, From}, {start, _Timeout},
#state{protocol_specific = #{error := Error}} = State) ->
{stop_and_reply, {shutdown, normal},
[{reply, From, {error, Error}}], State};
error({call, _} = Call, Msg, State) ->
gen_handshake(?FUNCTION_NAME, Call, Msg, State);
error(_, _, _) ->
{keep_state_and_data, [postpone]}.
%%--------------------------------------------------------------------
-spec hello(gen_statem:event_type(),
#hello_request{} | #client_hello{} | #server_hello{} | term(),
#state{}) ->
gen_statem:state_function_result().
%%--------------------------------------------------------------------
hello(internal, #client_hello{extensions = Extensions} = Hello,
#state{ssl_options = #ssl_options{handshake = hello},
start_or_recv_from = From} = State) ->
{next_state, user_hello, State#state{start_or_recv_from = undefined,
hello = Hello},
[{reply, From, {ok, ssl_connection:map_extensions(Extensions)}}]};
hello(internal, #server_hello{extensions = Extensions} = Hello,
#state{ssl_options = #ssl_options{handshake = hello},
start_or_recv_from = From} = State) ->
{next_state, user_hello, State#state{start_or_recv_from = undefined,
hello = Hello},
[{reply, From, {ok, ssl_connection:map_extensions(Extensions)}}]};
hello(internal, #client_hello{client_version = ClientVersion} = Hello,
#state{connection_states = ConnectionStates0,
static_env = #static_env{
port = Port,
session_cache = Cache,
session_cache_cb = CacheCb},
session = #session{own_certificate = Cert} = Session0,
renegotiation = {Renegotiation, _},
negotiated_protocol = CurrentProtocol,
key_algorithm = KeyExAlg,
ssl_options = SslOpts} = State) ->
case tls_handshake:hello(Hello, SslOpts, {Port, Session0, Cache, CacheCb,
ConnectionStates0, Cert, KeyExAlg}, Renegotiation) of
#alert{} = Alert ->
ssl_connection:handle_own_alert(Alert, ClientVersion, hello,
State#state{negotiated_version
= ClientVersion});
{Version, {Type, Session},
ConnectionStates, Protocol0, ServerHelloExt, HashSign} ->
Protocol = case Protocol0 of
undefined -> CurrentProtocol;
_ -> Protocol0
end,
gen_handshake(?FUNCTION_NAME, internal, {common_client_hello, Type, ServerHelloExt},
State#state{connection_states = ConnectionStates,
negotiated_version = Version,
hashsign_algorithm = HashSign,
client_hello_version = ClientVersion,
session = Session,
negotiated_protocol = Protocol})
end;
hello(internal, #server_hello{} = Hello,
#state{connection_states = ConnectionStates0,
negotiated_version = ReqVersion,
static_env = #static_env{role = client},
renegotiation = {Renegotiation, _},
ssl_options = SslOptions} = State) ->
case tls_handshake:hello(Hello, SslOptions, ConnectionStates0, Renegotiation) of
#alert{} = Alert ->
ssl_connection:handle_own_alert(Alert, ReqVersion, hello,
State#state{negotiated_version = ReqVersion});
{Version, NewId, ConnectionStates, ProtoExt, Protocol} ->
ssl_connection:handle_session(Hello,
Version, NewId, ConnectionStates, ProtoExt, Protocol, State)
end;
hello(info, Event, State) ->
gen_info(Event, ?FUNCTION_NAME, State);
hello(Type, Event, State) ->
gen_handshake(?FUNCTION_NAME, Type, Event, State).
user_hello(Type, Event, State) ->
gen_handshake(?FUNCTION_NAME, Type, Event, State).
%%--------------------------------------------------------------------
-spec abbreviated(gen_statem:event_type(), term(), #state{}) ->
gen_statem:state_function_result().
%%--------------------------------------------------------------------
abbreviated(info, Event, State) ->
gen_info(Event, ?FUNCTION_NAME, State);
abbreviated(Type, Event, State) ->
gen_handshake(?FUNCTION_NAME, Type, Event, State).
%%--------------------------------------------------------------------
-spec certify(gen_statem:event_type(), term(), #state{}) ->
gen_statem:state_function_result().
%%--------------------------------------------------------------------
certify(info, Event, State) ->
gen_info(Event, ?FUNCTION_NAME, State);
certify(Type, Event, State) ->
gen_handshake(?FUNCTION_NAME, Type, Event, State).
%%--------------------------------------------------------------------
-spec cipher(gen_statem:event_type(), term(), #state{}) ->
gen_statem:state_function_result().
%%--------------------------------------------------------------------
cipher(info, Event, State) ->
gen_info(Event, ?FUNCTION_NAME, State);
cipher(Type, Event, State) ->
gen_handshake(?FUNCTION_NAME, Type, Event, State).
%%--------------------------------------------------------------------
-spec connection(gen_statem:event_type(),
#hello_request{} | #client_hello{}| term(), #state{}) ->
gen_statem:state_function_result().
%%--------------------------------------------------------------------
connection(info, Event, State) ->
gen_info(Event, ?FUNCTION_NAME, State);
connection({call, From}, {user_renegotiate, WriteState},
#state{connection_states = ConnectionStates} = State) ->
{next_state, ?FUNCTION_NAME, State#state{connection_states = ConnectionStates#{current_write => WriteState}},
[{next_event,{call, From}, renegotiate}]};
connection({call, From},
{close, {Pid, _Timeout}},
#state{terminated = closed} = State) ->
{next_state, downgrade, State#state{terminated = true, downgrade = {Pid, From}},
[{next_event, internal, ?ALERT_REC(?WARNING, ?CLOSE_NOTIFY)}]};
connection({call, From},
{close,{Pid, Timeout}},
#state{connection_states = ConnectionStates,
protocol_specific = #{sender := Sender}
} = State0) ->
case tls_sender:downgrade(Sender, Timeout) of
{ok, Write} ->
%% User downgrades connection
%% When downgrading an TLS connection to a transport connection
%% we must recive the close alert from the peer before releasing the
%% transport socket.
State = send_alert(?ALERT_REC(?WARNING, ?CLOSE_NOTIFY),
State0#state{connection_states =
ConnectionStates#{current_write => Write}}),
{next_state, downgrade, State#state{downgrade = {Pid, From},
terminated = true}, [{timeout, Timeout, downgrade}]};
{error, timeout} ->
{stop_and_reply, {shutdown, downgrade_fail}, [{reply, From, {error, timeout}}]}
end;
connection(internal, #hello_request{},
#state{static_env = #static_env{role = client,
host = Host,
port = Port,
session_cache = Cache,
session_cache_cb = CacheCb},
renegotiation = {Renegotiation, _},
session = #session{own_certificate = Cert} = Session0,
ssl_options = SslOpts,
connection_states = ConnectionStates} = State0) ->
Hello = tls_handshake:client_hello(Host, Port, ConnectionStates, SslOpts,
Cache, CacheCb, Renegotiation, Cert),
{State, Actions} = send_handshake(Hello, State0),
next_event(hello, no_record, State#state{session = Session0#session{session_id
= Hello#client_hello.session_id}}, Actions);
connection(internal, #client_hello{} = Hello,
#state{static_env = #static_env{role = server},
allow_renegotiate = true,
connection_states = CS,
protocol_specific = #{sender := Sender}
} = 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),
{ok, Write} = tls_sender:renegotiate(Sender),
next_event(hello, no_record, State#state{connection_states = CS#{current_write => Write},
allow_renegotiate = false,
renegotiation = {true, peer}
},
[{next_event, internal, Hello}]);
connection(internal, #client_hello{},
#state{static_env = #static_env{role = server,
protocol_cb = Connection},
allow_renegotiate = false} = State0) ->
Alert = ?ALERT_REC(?WARNING, ?NO_RENEGOTIATION),
send_alert_in_connection(Alert, State0),
State = Connection:reinit_handshake_data(State0),
next_event(?FUNCTION_NAME, no_record, State);
connection(Type, Event, State) ->
ssl_connection:?FUNCTION_NAME(Type, Event, State, ?MODULE).
%%--------------------------------------------------------------------
-spec downgrade(gen_statem:event_type(), term(), #state{}) ->
gen_statem:state_function_result().
%%--------------------------------------------------------------------
downgrade(internal, #alert{description = ?CLOSE_NOTIFY},
#state{static_env = #static_env{transport_cb = Transport,
socket = Socket},
downgrade = {Pid, From}} = State) ->
tls_socket:setopts(Transport, Socket, [{active, false}, {packet, 0}, {mode, binary}]),
Transport:controlling_process(Socket, Pid),
{stop_and_reply, {shutdown, downgrade},[{reply, From, {ok, Socket}}], State};
downgrade(timeout, downgrade, #state{downgrade = {_, From}} = State) ->
{stop_and_reply, {shutdown, normal},[{reply, From, {error, timeout}}], State};
downgrade(info, {CloseTag, Socket},
#state{static_env = #static_env{socket = Socket,
close_tag = CloseTag}, downgrade = {_, From}} =
State) ->
{stop_and_reply, {shutdown, normal},[{reply, From, {error, CloseTag}}], State};
downgrade(info, Info, State) ->
handle_info(Info, ?FUNCTION_NAME, State);
downgrade(Type, Event, State) ->
ssl_connection:?FUNCTION_NAME(Type, Event, State, ?MODULE).
%--------------------------------------------------------------------
%% gen_statem callbacks
%%--------------------------------------------------------------------
callback_mode() ->
state_functions.
terminate({shutdown, sender_died, Reason}, _StateName,
#state{static_env = #static_env{socket = Socket,
transport_cb = Transport}}
= State) ->
ssl_connection:handle_trusted_certs_db(State),
close(Reason, Socket, Transport, undefined, undefined);
terminate(Reason, StateName, State) ->
catch ssl_connection:terminate(Reason, StateName, State),
ensure_sender_terminate(Reason, State).
format_status(Type, Data) ->
ssl_connection:format_status(Type, Data).
code_change(_OldVsn, StateName, State, _) ->
{ok, StateName, State}.
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
initial_state(Role, Sender, Host, Port, Socket, {SSLOptions, SocketOptions, Tracker}, User,
{CbModule, DataTag, CloseTag, ErrorTag}) ->
#ssl_options{beast_mitigation = BeastMitigation,
erl_dist = IsErlDist} = SSLOptions,
ConnectionStates = tls_record:init_connection_states(Role, BeastMitigation),
ErlDistData = erl_dist_data(IsErlDist),
SessionCacheCb = case application:get_env(ssl, session_cb) of
{ok, Cb} when is_atom(Cb) ->
Cb;
_ ->
ssl_session_cache
end,
InternalActiveN = case application:get_env(ssl, internal_active_n) of
{ok, N} when is_integer(N) andalso (not IsErlDist) ->
N;
_ ->
?INTERNAL_ACTIVE_N
end,
UserMonitor = erlang:monitor(process, User),
InitStatEnv = #static_env{
role = Role,
transport_cb = CbModule,
protocol_cb = ?MODULE,
data_tag = DataTag,
close_tag = CloseTag,
error_tag = ErrorTag,
host = Host,
port = Port,
socket = Socket,
session_cache_cb = SessionCacheCb,
tracker = Tracker
},
#state{
static_env = InitStatEnv,
socket_options = SocketOptions,
ssl_options = SSLOptions,
session = #session{is_resumable = new},
erl_dist_data = ErlDistData,
connection_states = ConnectionStates,
protocol_buffers = #protocol_buffers{},
user_application = {UserMonitor, User},
user_data_buffer = <<>>,
renegotiation = {false, first},
allow_renegotiate = SSLOptions#ssl_options.client_renegotiation,
start_or_recv_from = undefined,
flight_buffer = [],
protocol_specific = #{sender => Sender,
active_n => InternalActiveN,
active_n_toggle => true
}
}.
erl_dist_data(true) ->
#{dist_handle => undefined,
dist_buffer => <<>>};
erl_dist_data(false) ->
#{}.
initialize_tls_sender(#state{static_env = #static_env{
role = Role,
transport_cb = Transport,
protocol_cb = Connection,
socket = Socket,
tracker = Tracker
},
socket_options = SockOpts,
negotiated_version = Version,
ssl_options = #ssl_options{renegotiate_at = RenegotiateAt},
connection_states = #{current_write := ConnectionWriteState},
protocol_specific = #{sender := Sender}}) ->
Init = #{current_write => ConnectionWriteState,
role => Role,
socket => Socket,
socket_options => SockOpts,
tracker => Tracker,
protocol_cb => Connection,
transport_cb => Transport,
negotiated_version => Version,
renegotiate_at => RenegotiateAt},
tls_sender:initialize(Sender, Init).
next_tls_record(Data, StateName, #state{protocol_buffers =
#protocol_buffers{tls_record_buffer = Buf0,
tls_cipher_texts = CT0} = Buffers}
= State0) ->
case tls_record:get_tls_records(Data,
acceptable_record_versions(StateName, State0),
Buf0) of
{Records, Buf1} ->
CT1 = CT0 ++ Records,
next_record(State0#state{protocol_buffers =
Buffers#protocol_buffers{tls_record_buffer = Buf1,
tls_cipher_texts = CT1}});
#alert{} = Alert ->
handle_record_alert(Alert, State0)
end.
acceptable_record_versions(StateName, #state{negotiated_version = Version}) when StateName =/= hello->
Version;
acceptable_record_versions(hello, _) ->
[tls_record:protocol_version(Vsn) || Vsn <- ?ALL_AVAILABLE_VERSIONS].
handle_record_alert(Alert, _) ->
Alert.
tls_handshake_events(Packets) ->
lists:map(fun(Packet) ->
{next_event, internal, {handshake, Packet}}
end, Packets).
%% raw data from socket, upack records
handle_info({Protocol, _, Data}, StateName,
#state{static_env = #static_env{data_tag = Protocol}} = State0) ->
case next_tls_record(Data, StateName, State0) of
{Record, State} ->
next_event(StateName, Record, State);
#alert{} = Alert ->
ssl_connection:handle_normal_shutdown(Alert, StateName, State0),
{stop, {shutdown, own_alert}, State0}
end;
handle_info({tcp_passive, Socket}, StateName,
#state{static_env = #static_env{socket = Socket},
protocol_specific = PS
} = State) ->
next_event(StateName, no_record,
State#state{protocol_specific = PS#{active_n_toggle => true}});
handle_info({CloseTag, Socket}, StateName,
#state{static_env = #static_env{socket = Socket, close_tag = CloseTag},
socket_options = #socket_options{active = Active},
protocol_buffers = #protocol_buffers{tls_cipher_texts = CTs},
user_data_buffer = Buffer,
protocol_specific = PS,
negotiated_version = Version} = State) ->
%% Note that as of TLS 1.1,
%% failure to properly close a connection no longer requires that a
%% session not be resumed. This is a change from TLS 1.0 to conform
%% with widespread implementation practice.
case (Active == false) andalso ((CTs =/= []) or (Buffer =/= <<>>)) of
false ->
case Version of
{1, N} when N >= 1 ->
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}, State};
true ->
%% Fixes non-delivery of final TLS record in {active, once}.
%% Basically allows the application the opportunity to set {active, once} again
%% and then receive the final message. Set internal active_n to zero
%% to ensure socket close message is sent if there is not enough data to deliver.
next_event(StateName, no_record, State#state{protocol_specific = PS#{active_n_toggle => true}})
end;
handle_info({'EXIT', Sender, Reason}, _,
#state{protocol_specific = #{sender := Sender}} = State) ->
{stop, {shutdown, sender_died, Reason}, State};
handle_info(Msg, StateName, State) ->
ssl_connection:StateName(info, Msg, State, ?MODULE).
handle_alerts([], Result) ->
Result;
handle_alerts(_, {stop, _, _} = Stop) ->
Stop;
handle_alerts([Alert | Alerts], {next_state, StateName, State}) ->
handle_alerts(Alerts, ssl_connection:handle_alert(Alert, StateName, State));
handle_alerts([Alert | Alerts], {next_state, StateName, State, _Actions}) ->
handle_alerts(Alerts, ssl_connection:handle_alert(Alert, StateName, State)).
encode_handshake(Handshake, Version, ConnectionStates0, Hist0) ->
Frag = tls_handshake:encode_handshake(Handshake, Version),
Hist = ssl_handshake:update_handshake_history(Hist0, Frag),
{Encoded, ConnectionStates} =
tls_record:encode_handshake(Frag, Version, ConnectionStates0),
{Encoded, ConnectionStates, Hist}.
encode_change_cipher(#change_cipher_spec{}, Version, ConnectionStates) ->
tls_record:encode_change_cipher_spec(Version, ConnectionStates).
decode_alerts(Bin) ->
ssl_alert:decode(Bin).
gen_handshake(StateName, Type, Event,
#state{negotiated_version = Version} = State) ->
try ssl_connection:StateName(Type, Event, State, ?MODULE) of
Result ->
Result
catch
_:_ ->
ssl_connection:handle_own_alert(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE,
malformed_handshake_data),
Version, StateName, State)
end.
gen_info(Event, connection = StateName, #state{negotiated_version = Version} = State) ->
try handle_info(Event, StateName, State) of
Result ->
Result
catch
_:_ ->
ssl_connection:handle_own_alert(?ALERT_REC(?FATAL, ?INTERNAL_ERROR,
malformed_data),
Version, StateName, State)
end;
gen_info(Event, StateName, #state{negotiated_version = Version} = State) ->
try handle_info(Event, StateName, State) of
Result ->
Result
catch
_:_ ->
ssl_connection:handle_own_alert(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE,
malformed_handshake_data),
Version, StateName, State)
end.
unprocessed_events(Events) ->
%% The first handshake event will be processed immediately
%% as it is entered first in the event queue and
%% when it is processed there will be length(Events)-1
%% handshake events left to process before we should
%% process more TLS-records received on the socket.
erlang:length(Events)-1.
assert_buffer_sanity(<<?BYTE(_Type), ?UINT24(Length), Rest/binary>>,
#ssl_options{max_handshake_size = Max}) when
Length =< Max ->
case size(Rest) of
N when N < Length ->
true;
N when N > Length ->
throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE,
too_big_handshake_data));
_ ->
throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE,
malformed_handshake_data))
end;
assert_buffer_sanity(Bin, _) ->
case size(Bin) of
N when N < 3 ->
true;
_ ->
throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE,
malformed_handshake_data))
end.
ensure_sender_terminate(downgrade, _) ->
ok; %% Do not terminate sender during downgrade phase
ensure_sender_terminate(_, #state{protocol_specific = #{sender := Sender}}) ->
%% Make sure TLS sender dies when connection process is terminated normally
%% This is needed if the tls_sender is blocked in prim_inet:send
Kill = fun() ->
receive
after 5000 ->
catch (exit(Sender, kill))
end
end,
spawn(Kill).
