%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2008-2016. 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 ssh connection, e.i. both the
%% setup SSH Transport Layer Protocol (RFC 4253), Authentication
%% Protocol (RFC 4252) and SSH connection Protocol (RFC 4255)
%% Details of the different protocols are
%% implemented in ssh_transport.erl, ssh_auth.erl and ssh_connection.erl
%% ----------------------------------------------------------------------
-module(ssh_connection_handler).
-behaviour(gen_statem).
-include("ssh.hrl").
-include("ssh_transport.hrl").
-include("ssh_auth.hrl").
-include("ssh_connect.hrl").
%%====================================================================
%%% Exports
%%====================================================================
%%% Start and stop
-export([start_link/3,
stop/1
]).
%%% Internal application API
-export([start_connection/4,
open_channel/6,
request/6, request/7,
reply_request/3,
global_request/4,
send/5,
send_eof/2,
info/1, info/2,
connection_info/2,
channel_info/3,
adjust_window/3, close/2,
disconnect/1, disconnect/2,
get_print_info/1
]).
%%% Behaviour callbacks
-export([handle_event/4, terminate/3, format_status/2, code_change/4]).
%%% Exports not intended to be used :). They are used for spawning and tests
-export([init_connection_handler/3, % proc_lib:spawn needs this
init_ssh_record/3, % Export of this internal function
% intended for low-level protocol test suites
renegotiate/1, renegotiate_data/1 % Export intended for test cases
]).
%%====================================================================
%% Start / stop
%%====================================================================
%%--------------------------------------------------------------------
-spec start_link(role(),
inet:socket(),
proplists:proplist()
) -> {ok, pid()}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
start_link(Role, Socket, Options) ->
{ok, proc_lib:spawn_link(?MODULE, init_connection_handler, [Role, Socket, Options])}.
%%--------------------------------------------------------------------
-spec stop(connection_ref()
) -> ok | {error, term()}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
stop(ConnectionHandler)->
case call(ConnectionHandler, stop) of
{error, closed} ->
ok;
Other ->
Other
end.
%%====================================================================
%% Internal application API
%%====================================================================
-define(DefaultTransport, {tcp, gen_tcp, tcp_closed} ).
%%--------------------------------------------------------------------
-spec start_connection(role(),
inet:socket(),
proplists:proplist(),
timeout()
) -> {ok, connection_ref()} | {error, term()}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
start_connection(client = Role, Socket, Options, Timeout) ->
try
{ok, Pid} = sshc_sup:start_child([Role, Socket, Options]),
ok = socket_control(Socket, Pid, Options),
handshake(Pid, erlang:monitor(process,Pid), Timeout)
catch
exit:{noproc, _} ->
{error, ssh_not_started};
_:Error ->
{error, Error}
end;
start_connection(server = Role, Socket, Options, Timeout) ->
SSH_Opts = proplists:get_value(ssh_opts, Options, []),
try
case proplists:get_value(parallel_login, SSH_Opts, false) of
true ->
HandshakerPid =
spawn_link(fun() ->
receive
{do_handshake, Pid} ->
handshake(Pid, erlang:monitor(process,Pid), Timeout)
end
end),
ChildPid = start_the_connection_child(HandshakerPid, Role, Socket, Options),
HandshakerPid ! {do_handshake, ChildPid};
false ->
ChildPid = start_the_connection_child(self(), Role, Socket, Options),
handshake(ChildPid, erlang:monitor(process,ChildPid), Timeout)
end
catch
exit:{noproc, _} ->
{error, ssh_not_started};
_:Error ->
{error, Error}
end.
%%--------------------------------------------------------------------
%%% Some other module has decided to disconnect.
-spec disconnect(#ssh_msg_disconnect{}) -> no_return().
-spec disconnect(#ssh_msg_disconnect{}, iodata()) -> no_return().
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
disconnect(Msg = #ssh_msg_disconnect{}) ->
throw({keep_state_and_data,
[{next_event, internal, {disconnect, Msg, Msg#ssh_msg_disconnect.description}}]}).
disconnect(Msg = #ssh_msg_disconnect{}, ExtraInfo) ->
throw({keep_state_and_data,
[{next_event, internal, {disconnect, Msg, {Msg#ssh_msg_disconnect.description,ExtraInfo}}}]}).
%%--------------------------------------------------------------------
-spec open_channel(connection_ref(),
string(),
iodata(),
pos_integer(),
pos_integer(),
timeout()
) -> {open, channel_id()} | {error, term()}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
open_channel(ConnectionHandler,
ChannelType, ChannelSpecificData, InitialWindowSize, MaxPacketSize,
Timeout) ->
call(ConnectionHandler,
{open,
self(),
ChannelType, InitialWindowSize, MaxPacketSize, ChannelSpecificData,
Timeout}).
%%--------------------------------------------------------------------
-spec request(connection_ref(),
pid(),
channel_id(),
string(),
boolean(),
iodata(),
timeout()
) -> success | failure | ok | {error,timeout}.
-spec request(connection_ref(),
channel_id(),
string(),
boolean(),
iodata(),
timeout()
) -> success | failure | ok | {error,timeout}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
request(ConnectionHandler, ChannelPid, ChannelId, Type, true, Data, Timeout) ->
call(ConnectionHandler, {request, ChannelPid, ChannelId, Type, Data, Timeout});
request(ConnectionHandler, ChannelPid, ChannelId, Type, false, Data, _) ->
cast(ConnectionHandler, {request, ChannelPid, ChannelId, Type, Data}).
request(ConnectionHandler, ChannelId, Type, true, Data, Timeout) ->
call(ConnectionHandler, {request, ChannelId, Type, Data, Timeout});
request(ConnectionHandler, ChannelId, Type, false, Data, _) ->
cast(ConnectionHandler, {request, ChannelId, Type, Data}).
%%--------------------------------------------------------------------
-spec reply_request(connection_ref(),
success | failure,
channel_id()
) -> ok.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
reply_request(ConnectionHandler, Status, ChannelId) ->
cast(ConnectionHandler, {reply_request, Status, ChannelId}).
%%--------------------------------------------------------------------
-spec global_request(connection_ref(),
string(),
boolean(),
iolist()
) -> ok | error.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
global_request(ConnectionHandler, Type, true = Reply, Data) ->
case call(ConnectionHandler, {global_request, self(), Type, Reply, Data}) of
{ssh_cm, ConnectionHandler, {success, _}} ->
ok;
{ssh_cm, ConnectionHandler, {failure, _}} ->
error
end;
global_request(ConnectionHandler, Type, false = Reply, Data) ->
cast(ConnectionHandler, {global_request, self(), Type, Reply, Data}).
%%--------------------------------------------------------------------
-spec send(connection_ref(),
channel_id(),
non_neg_integer(),
iodata(),
timeout()
) -> ok | {error, timeout|closed}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
send(ConnectionHandler, ChannelId, Type, Data, Timeout) ->
call(ConnectionHandler, {data, ChannelId, Type, Data, Timeout}).
%%--------------------------------------------------------------------
-spec send_eof(connection_ref(),
channel_id()
) -> ok | {error,closed}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
send_eof(ConnectionHandler, ChannelId) ->
call(ConnectionHandler, {eof, ChannelId}).
%%--------------------------------------------------------------------
-spec info(connection_ref()
) -> {ok, [#channel{}]} .
-spec info(connection_ref(),
pid() | all
) -> {ok, [#channel{}]} .
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
info(ConnectionHandler) ->
info(ConnectionHandler, all).
info(ConnectionHandler, ChannelProcess) ->
call(ConnectionHandler, {info, ChannelProcess}).
%%--------------------------------------------------------------------
-type local_sock_info() :: {inet:ip_address(), non_neg_integer()} | string().
-type peer_sock_info() :: {inet:ip_address(), non_neg_integer()} | string().
-type state_info() :: iolist().
-spec get_print_info(connection_ref()
) -> {{local_sock_info(), peer_sock_info()},
state_info()
}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
get_print_info(ConnectionHandler) ->
call(ConnectionHandler, get_print_info, 1000).
%%--------------------------------------------------------------------
-spec connection_info(connection_ref(),
[atom()]
) -> proplists:proplist().
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
connection_info(ConnectionHandler, Options) ->
call(ConnectionHandler, {connection_info, Options}).
%%--------------------------------------------------------------------
-spec channel_info(connection_ref(),
channel_id(),
[atom()]
) -> proplists:proplist().
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
channel_info(ConnectionHandler, ChannelId, Options) ->
call(ConnectionHandler, {channel_info, ChannelId, Options}).
%%--------------------------------------------------------------------
-spec adjust_window(connection_ref(),
channel_id(),
integer()
) -> ok.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
adjust_window(ConnectionHandler, Channel, Bytes) ->
cast(ConnectionHandler, {adjust_window, Channel, Bytes}).
%%--------------------------------------------------------------------
-spec close(connection_ref(),
channel_id()
) -> ok.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
close(ConnectionHandler, ChannelId) ->
case call(ConnectionHandler, {close, ChannelId}) of
ok ->
ok;
{error, closed} ->
ok
end.
%%====================================================================
%% Test support
%%====================================================================
%%--------------------------------------------------------------------
-spec renegotiate(connection_ref()
) -> ok.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
renegotiate(ConnectionHandler) ->
cast(ConnectionHandler, renegotiate).
%%--------------------------------------------------------------------
-spec renegotiate_data(connection_ref()
) -> ok.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
renegotiate_data(ConnectionHandler) ->
cast(ConnectionHandler, data_size).
%%====================================================================
%% Internal process state
%%====================================================================
-record(data, {
starter :: pid(),
auth_user :: string()
| undefined,
connection_state :: #connection{},
latest_channel_id = 0 :: non_neg_integer(),
idle_timer_ref :: undefined
| infinity
| reference(),
idle_timer_value = infinity :: infinity
| pos_integer(),
transport_protocol :: atom(), % ex: tcp
transport_cb :: atom(), % ex: gen_tcp
transport_close_tag :: atom(), % ex: tcp_closed
ssh_params :: #ssh{}
| undefined,
socket :: inet:socket(),
decrypted_data_buffer = <<>> :: binary(),
encrypted_data_buffer = <<>> :: binary(),
undecrypted_packet_length :: undefined | non_neg_integer(),
key_exchange_init_msg :: #ssh_msg_kexinit{}
| undefined,
last_size_rekey = 0 :: non_neg_integer(),
event_queue = [] :: list(),
opts :: proplists:proplist(),
inet_initial_recbuf_size :: pos_integer()
| undefined
}).
%%====================================================================
%% Intitialisation
%%====================================================================
%%--------------------------------------------------------------------
-spec init_connection_handler(role(),
inet:socket(),
proplists:proplist()
) -> no_return().
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
init_connection_handler(Role, Socket, Opts) ->
process_flag(trap_exit, true),
S0 = init_process_state(Role, Socket, Opts),
try
{Protocol, Callback, CloseTag} =
proplists:get_value(transport, Opts, ?DefaultTransport),
S0#data{ssh_params = init_ssh_record(Role, Socket, Opts),
transport_protocol = Protocol,
transport_cb = Callback,
transport_close_tag = CloseTag
}
of
S ->
gen_statem:enter_loop(?MODULE,
[], %%[{debug,[trace,log,statistics,debug]} || Role==server],
handle_event_function,
{hello,Role},
S)
catch
_:Error ->
gen_statem:enter_loop(?MODULE,
[],
handle_event_function,
{init_error,Error},
S0)
end.
init_process_state(Role, Socket, Opts) ->
D = #data{connection_state =
C = #connection{channel_cache = ssh_channel:cache_create(),
channel_id_seed = 0,
port_bindings = [],
requests = [],
options = Opts},
starter = proplists:get_value(user_pid, Opts),
socket = Socket,
opts = Opts
},
case Role of
client ->
%% Start the renegotiation timers
timer:apply_after(?REKEY_TIMOUT, gen_statem, cast, [self(), renegotiate]),
timer:apply_after(?REKEY_DATA_TIMOUT, gen_statem, cast, [self(), data_size]),
cache_init_idle_timer(D);
server ->
D#data{connection_state = init_connection(Role, C, Opts)}
end.
init_connection(server, C = #connection{}, Opts) ->
Sups = proplists:get_value(supervisors, Opts),
SystemSup = proplists:get_value(system_sup, Sups),
SubSystemSup = proplists:get_value(subsystem_sup, Sups),
ConnectionSup = proplists:get_value(connection_sup, Sups),
Shell = proplists:get_value(shell, Opts),
Exec = proplists:get_value(exec, Opts),
CliSpec = proplists:get_value(ssh_cli, Opts, {ssh_cli, [Shell]}),
C#connection{cli_spec = CliSpec,
exec = Exec,
system_supervisor = SystemSup,
sub_system_supervisor = SubSystemSup,
connection_supervisor = ConnectionSup
}.
init_ssh_record(Role, Socket, Opts) ->
{ok, PeerAddr} = inet:peername(Socket),
KeyCb = proplists:get_value(key_cb, Opts, ssh_file),
AuthMethods = proplists:get_value(auth_methods, Opts, ?SUPPORTED_AUTH_METHODS),
S0 = #ssh{role = Role,
key_cb = KeyCb,
opts = Opts,
userauth_supported_methods = AuthMethods,
available_host_keys = supported_host_keys(Role, KeyCb, Opts),
random_length_padding = proplists:get_value(max_random_length_padding,
Opts,
(#ssh{})#ssh.random_length_padding)
},
{Vsn, Version} = ssh_transport:versions(Role, Opts),
case Role of
client ->
PeerName = proplists:get_value(host, Opts),
S0#ssh{c_vsn = Vsn,
c_version = Version,
io_cb = case proplists:get_value(user_interaction, Opts, true) of
true -> ssh_io;
false -> ssh_no_io
end,
userauth_quiet_mode = proplists:get_value(quiet_mode, Opts, false),
peer = {PeerName, PeerAddr}
};
server ->
S0#ssh{s_vsn = Vsn,
s_version = Version,
io_cb = proplists:get_value(io_cb, Opts, ssh_io),
userauth_methods = string:tokens(AuthMethods, ","),
kb_tries_left = 3,
peer = {undefined, PeerAddr}
}
end.
%%====================================================================
%% gen_statem callbacks
%%====================================================================
%%--------------------------------------------------------------------
-type event_content() :: any().
-type renegotiate_flag() :: init | renegotiate.
-type state_name() ::
{init_error,any()}
| {hello, role()}
| {kexinit, role(), renegotiate_flag()}
| {key_exchange, role(), renegotiate_flag()}
| {key_exchange_dh_gex_init, server, renegotiate_flag()}
| {key_exchange_dh_gex_reply, client, renegotiate_flag()}
| {new_keys, role()}
| {service_request, role()}
| {userauth, role()}
| {userauth_keyboard_interactive, role()}
| {connected, role()}
.
-type handle_event_result() :: gen_statem:handle_event_result().
-spec handle_event(gen_statem:event_type(),
event_content(),
state_name(),
#data{}
) -> handle_event_result().
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
%%% ######## Error in the initialisation ####
handle_event(_, _Event, {init_error,Error}, _) ->
case Error of
{badmatch,{error,enotconn}} ->
%% Handles the abnormal sequence:
%% SYN->
%% <-SYNACK
%% ACK->
%% RST->
{stop, {shutdown,"TCP connenction to server was prematurely closed by the client"}};
OtherError ->
{stop, {shutdown,{init,OtherError}}}
end;
%%% ######## {hello, client|server} ####
%% The very first event that is sent when the we are set as controlling process of Socket
handle_event(_, socket_control, {hello,_}, D) ->
VsnMsg = ssh_transport:hello_version_msg(string_version(D#data.ssh_params)),
ok = send_bytes(VsnMsg, D),
case inet:getopts(Socket=D#data.socket, [recbuf]) of
{ok, [{recbuf,Size}]} ->
%% Set the socket to the hello text line handling mode:
inet:setopts(Socket, [{packet, line},
{active, once},
% Expecting the version string which might
% be max ?MAX_PROTO_VERSION bytes:
{recbuf, ?MAX_PROTO_VERSION},
{nodelay,true}]),
{keep_state, D#data{inet_initial_recbuf_size=Size}};
Other ->
{stop, {shutdown,{unexpected_getopts_return, Other}}}
end;
handle_event(_, {info_line,_Line}, {hello,Role}, D) ->
case Role of
client ->
%% The server may send info lines to the client before the version_exchange
inet:setopts(D#data.socket, [{active, once}]),
keep_state_and_data;
server ->
%% But the client may NOT send them to the server. Openssh answers with cleartext,
%% and so do we
ok = send_bytes("Protocol mismatch.", D),
{stop, {shutdown,"Protocol mismatch in version exchange. Client sent info lines."}}
end;
handle_event(_, {version_exchange,Version}, {hello,Role}, D) ->
{NumVsn, StrVsn} = ssh_transport:handle_hello_version(Version),
case handle_version(NumVsn, StrVsn, D#data.ssh_params) of
{ok, Ssh1} ->
%% Since the hello part is finnished correctly, we set the
%% socket to the packet handling mode (including recbuf size):
inet:setopts(D#data.socket, [{packet,0},
{mode,binary},
{active, once},
{recbuf, D#data.inet_initial_recbuf_size}]),
{KeyInitMsg, SshPacket, Ssh} = ssh_transport:key_exchange_init_msg(Ssh1),
ok = send_bytes(SshPacket, D),
{next_state, {kexinit,Role,init}, D#data{ssh_params = Ssh,
key_exchange_init_msg = KeyInitMsg}};
not_supported ->
disconnect(
#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED,
description = ["Protocol version ",StrVsn," not supported"]},
{next_state, {hello,Role}, D})
end;
%%% ######## {kexinit, client|server, init|renegotiate} ####
handle_event(_, {#ssh_msg_kexinit{}=Kex, Payload}, {kexinit,Role,ReNeg},
D = #data{key_exchange_init_msg = OwnKex}) ->
Ssh1 = ssh_transport:key_init(peer_role(Role), D#data.ssh_params, Payload),
Ssh = case ssh_transport:handle_kexinit_msg(Kex, OwnKex, Ssh1) of
{ok, NextKexMsg, Ssh2} when Role==client ->
ok = send_bytes(NextKexMsg, D),
Ssh2;
{ok, Ssh2} when Role==server ->
Ssh2
end,
{next_state, {key_exchange,Role,ReNeg}, D#data{ssh_params=Ssh}};
%%% ######## {key_exchange, client|server, init|renegotiate} ####
%%%---- diffie-hellman
handle_event(_, #ssh_msg_kexdh_init{} = Msg, {key_exchange,server,ReNeg}, D) ->
{ok, KexdhReply, Ssh1} = ssh_transport:handle_kexdh_init(Msg, D#data.ssh_params),
ok = send_bytes(KexdhReply, D),
{ok, NewKeys, Ssh} = ssh_transport:new_keys_message(Ssh1),
ok = send_bytes(NewKeys, D),
{next_state, {new_keys,server,ReNeg}, D#data{ssh_params=Ssh}};
handle_event(_, #ssh_msg_kexdh_reply{} = Msg, {key_exchange,client,ReNeg}, D) ->
{ok, NewKeys, Ssh} = ssh_transport:handle_kexdh_reply(Msg, D#data.ssh_params),
ok = send_bytes(NewKeys, D),
{next_state, {new_keys,client,ReNeg}, D#data{ssh_params=Ssh}};
%%%---- diffie-hellman group exchange
handle_event(_, #ssh_msg_kex_dh_gex_request{} = Msg, {key_exchange,server,ReNeg}, D) ->
{ok, GexGroup, Ssh} = ssh_transport:handle_kex_dh_gex_request(Msg, D#data.ssh_params),
ok = send_bytes(GexGroup, D),
{next_state, {key_exchange_dh_gex_init,server,ReNeg}, D#data{ssh_params=Ssh}};
handle_event(_, #ssh_msg_kex_dh_gex_request_old{} = Msg, {key_exchange,server,ReNeg}, D) ->
{ok, GexGroup, Ssh} = ssh_transport:handle_kex_dh_gex_request(Msg, D#data.ssh_params),
ok = send_bytes(GexGroup, D),
{next_state, {key_exchange_dh_gex_init,server,ReNeg}, D#data{ssh_params=Ssh}};
handle_event(_, #ssh_msg_kex_dh_gex_group{} = Msg, {key_exchange,client,ReNeg}, D) ->
{ok, KexGexInit, Ssh} = ssh_transport:handle_kex_dh_gex_group(Msg, D#data.ssh_params),
ok = send_bytes(KexGexInit, D),
{next_state, {key_exchange_dh_gex_reply,client,ReNeg}, D#data{ssh_params=Ssh}};
%%%---- elliptic curve diffie-hellman
handle_event(_, #ssh_msg_kex_ecdh_init{} = Msg, {key_exchange,server,ReNeg}, D) ->
{ok, KexEcdhReply, Ssh1} = ssh_transport:handle_kex_ecdh_init(Msg, D#data.ssh_params),
ok = send_bytes(KexEcdhReply, D),
{ok, NewKeys, Ssh} = ssh_transport:new_keys_message(Ssh1),
ok = send_bytes(NewKeys, D),
{next_state, {new_keys,server,ReNeg}, D#data{ssh_params=Ssh}};
handle_event(_, #ssh_msg_kex_ecdh_reply{} = Msg, {key_exchange,client,ReNeg}, D) ->
{ok, NewKeys, Ssh} = ssh_transport:handle_kex_ecdh_reply(Msg, D#data.ssh_params),
ok = send_bytes(NewKeys, D),
{next_state, {new_keys,client,ReNeg}, D#data{ssh_params=Ssh}};
%%% ######## {key_exchange_dh_gex_init, server, init|renegotiate} ####
handle_event(_, #ssh_msg_kex_dh_gex_init{} = Msg, {key_exchange_dh_gex_init,server,ReNeg}, D) ->
{ok, KexGexReply, Ssh1} = ssh_transport:handle_kex_dh_gex_init(Msg, D#data.ssh_params),
ok = send_bytes(KexGexReply, D),
{ok, NewKeys, Ssh} = ssh_transport:new_keys_message(Ssh1),
ok = send_bytes(NewKeys, D),
{next_state, {new_keys,server,ReNeg}, D#data{ssh_params=Ssh}};
%%% ######## {key_exchange_dh_gex_reply, client, init|renegotiate} ####
handle_event(_, #ssh_msg_kex_dh_gex_reply{} = Msg, {key_exchange_dh_gex_reply,client,ReNeg}, D) ->
{ok, NewKeys, Ssh1} = ssh_transport:handle_kex_dh_gex_reply(Msg, D#data.ssh_params),
ok = send_bytes(NewKeys, D),
{next_state, {new_keys,client,ReNeg}, D#data{ssh_params=Ssh1}};
%%% ######## {new_keys, client|server} ####
%% First key exchange round:
handle_event(_, #ssh_msg_newkeys{} = Msg, {new_keys,Role,init}, D) ->
{ok, Ssh1} = ssh_transport:handle_new_keys(Msg, D#data.ssh_params),
Ssh = case Role of
client ->
{MsgReq, Ssh2} = ssh_auth:service_request_msg(Ssh1),
ok = send_bytes(MsgReq, D),
Ssh2;
server ->
Ssh1
end,
{next_state, {service_request,Role}, D#data{ssh_params=Ssh}};
%% Subsequent key exchange rounds (renegotiation):
handle_event(_, #ssh_msg_newkeys{}, {new_keys,Role,renegotiate}, D) ->
{next_state, {connected,Role}, D};
%%% ######## {service_request, client|server}
handle_event(_, Msg = #ssh_msg_service_request{name=ServiceName}, StateName = {service_request,server}, D) ->
case ServiceName of
"ssh-userauth" ->
Ssh0 = #ssh{session_id=SessionId} = D#data.ssh_params,
{ok, {Reply, Ssh}} = ssh_auth:handle_userauth_request(Msg, SessionId, Ssh0),
ok = send_bytes(Reply, D),
{next_state, {userauth,server}, D#data{ssh_params = Ssh}};
_ ->
disconnect(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_SERVICE_NOT_AVAILABLE,
description = "Unknown service"},
StateName, D)
end;
handle_event(_, #ssh_msg_service_accept{name = "ssh-userauth"}, {service_request,client},
#data{ssh_params = #ssh{service="ssh-userauth"} = Ssh0} = State) ->
{Msg, Ssh} = ssh_auth:init_userauth_request_msg(Ssh0),
ok = send_bytes(Msg, State),
{next_state, {userauth,client}, State#data{auth_user = Ssh#ssh.user, ssh_params = Ssh}};
%%% ######## {userauth, client|server} ####
%%---- userauth request to server
handle_event(_,
Msg = #ssh_msg_userauth_request{service = ServiceName, method = Method},
StateName = {userauth,server},
D = #data{ssh_params=Ssh0}) ->
case {ServiceName, Ssh0#ssh.service, Method} of
{"ssh-connection", "ssh-connection", "none"} ->
%% Probably the very first userauth_request but we deny unauthorized login
{not_authorized, _, {Reply,Ssh}} =
ssh_auth:handle_userauth_request(Msg, Ssh0#ssh.session_id, Ssh0),
ok = send_bytes(Reply, D),
{keep_state, D#data{ssh_params = Ssh}};
{"ssh-connection", "ssh-connection", Method} ->
%% Userauth request with a method like "password" or so
case lists:member(Method, Ssh0#ssh.userauth_methods) of
true ->
%% Yepp! we support this method
case ssh_auth:handle_userauth_request(Msg, Ssh0#ssh.session_id, Ssh0) of
{authorized, User, {Reply, Ssh}} ->
ok = send_bytes(Reply, D),
D#data.starter ! ssh_connected,
connected_fun(User, Method, D),
{next_state, {connected,server},
D#data{auth_user = User,
ssh_params = Ssh#ssh{authenticated = true}}};
{not_authorized, {User, Reason}, {Reply, Ssh}} when Method == "keyboard-interactive" ->
retry_fun(User, Reason, D),
ok = send_bytes(Reply, D),
{next_state, {userauth_keyboard_interactive,server}, D#data{ssh_params = Ssh}};
{not_authorized, {User, Reason}, {Reply, Ssh}} ->
retry_fun(User, Reason, D),
ok = send_bytes(Reply, D),
{keep_state, D#data{ssh_params = Ssh}}
end;
false ->
%% No we do not support this method (=/= none)
%% At least one non-erlang client does like this. Retry as the next event
{keep_state_and_data,
[{next_event, internal, Msg#ssh_msg_userauth_request{method="none"}}]
}
end;
%% {"ssh-connection", Expected, Method} when Expected =/= ServiceName -> Do what?
%% {ServiceName, Expected, Method} when Expected =/= ServiceName -> Do what?
{ServiceName, _, _} when ServiceName =/= "ssh-connection" ->
disconnect(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_SERVICE_NOT_AVAILABLE,
description = "Unknown service"},
StateName, D)
end;
%%---- userauth success to client
handle_event(_, #ssh_msg_userauth_success{}, {userauth,client}, D=#data{ssh_params = Ssh}) ->
D#data.starter ! ssh_connected,
{next_state, {connected,client}, D#data{ssh_params=Ssh#ssh{authenticated = true}}};
%%---- userauth failure response to client
handle_event(_, #ssh_msg_userauth_failure{}, {userauth,client}=StateName,
D = #data{ssh_params = #ssh{userauth_methods = []}}) ->
Msg = #ssh_msg_disconnect{code = ?SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
description = "Unable to connect using the available"
" authentication methods"},
disconnect(Msg, StateName, D);
handle_event(_, #ssh_msg_userauth_failure{authentications = Methods}, StateName={userauth,client},
D = #data{ssh_params = Ssh0}) ->
%% The prefered authentication method failed try next method
Ssh1 = case Ssh0#ssh.userauth_methods of
none ->
%% Server tells us which authentication methods that are allowed
Ssh0#ssh{userauth_methods = string:tokens(Methods, ",")};
_ ->
%% We already know...
Ssh0
end,
case ssh_auth:userauth_request_msg(Ssh1) of
{disconnect, DisconnectMsg, {Msg, Ssh}} ->
send_bytes(Msg, D),
disconnect(DisconnectMsg, StateName, D#data{ssh_params = Ssh});
{"keyboard-interactive", {Msg, Ssh}} ->
send_bytes(Msg, D),
{next_state, {userauth_keyboard_interactive,client}, D#data{ssh_params = Ssh}};
{_Method, {Msg, Ssh}} ->
send_bytes(Msg, D),
{keep_state, D#data{ssh_params = Ssh}}
end;
%%---- banner to client
handle_event(_, #ssh_msg_userauth_banner{message = Msg}, {userauth,client}, D) ->
case D#data.ssh_params#ssh.userauth_quiet_mode of
false -> io:format("~s", [Msg]);
true -> ok
end,
keep_state_and_data;
%%% ######## {userauth_keyboard_interactive, client|server}
handle_event(_, #ssh_msg_userauth_info_request{} = Msg, {userauth_keyboard_interactive, client},
#data{ssh_params = Ssh0} = D) ->
{ok, {Reply, Ssh}} = ssh_auth:handle_userauth_info_request(Msg, Ssh0#ssh.io_cb, Ssh0),
send_bytes(Reply, D),
{next_state, {userauth_keyboard_interactive_info_response,client}, D#data{ssh_params = Ssh}};
handle_event(_, #ssh_msg_userauth_info_response{} = Msg, {userauth_keyboard_interactive, server}, D) ->
case ssh_auth:handle_userauth_info_response(Msg, D#data.ssh_params) of
{authorized, User, {Reply, Ssh}} ->
send_bytes(Reply, D),
D#data.starter ! ssh_connected,
connected_fun(User, "keyboard-interactive", D),
{next_state, {connected,server}, D#data{auth_user = User,
ssh_params = Ssh#ssh{authenticated = true}}};
{not_authorized, {User, Reason}, {Reply, Ssh}} ->
retry_fun(User, Reason, D),
send_bytes(Reply, D),
{next_state, {userauth,server}, D#data{ssh_params = Ssh}}
end;
handle_event(_, Msg = #ssh_msg_userauth_failure{}, {userauth_keyboard_interactive, client},
#data{ssh_params = Ssh0} = D0) ->
Prefs = [{Method,M,F,A} || {Method,M,F,A} <- Ssh0#ssh.userauth_preference,
Method =/= "keyboard-interactive"],
D = D0#data{ssh_params = Ssh0#ssh{userauth_preference=Prefs}},
{next_state, {userauth,client}, D, [{next_event, internal, Msg}]};
handle_event(_, Msg=#ssh_msg_userauth_failure{}, {userauth_keyboard_interactive_info_response, client}, D) ->
{next_state, {userauth,client}, D, [{next_event, internal, Msg}]};
handle_event(_, Msg=#ssh_msg_userauth_success{}, {userauth_keyboard_interactive_info_response, client}, D) ->
{next_state, {userauth,client}, D, [{next_event, internal, Msg}]};
handle_event(_, Msg=#ssh_msg_userauth_info_request{}, {userauth_keyboard_interactive_info_response, client}, D) ->
{next_state, {userauth_keyboard_interactive,client}, D, [{next_event, internal, Msg}]};
%%% ######## {connected, client|server} ####
handle_event(_, {#ssh_msg_kexinit{},_} = Event, {connected,Role}, D0) ->
{KeyInitMsg, SshPacket, Ssh} = ssh_transport:key_exchange_init_msg(D0#data.ssh_params),
D = D0#data{ssh_params = Ssh,
key_exchange_init_msg = KeyInitMsg},
send_bytes(SshPacket, D),
{next_state, {kexinit,Role,renegotiate}, D, [{next_event, internal, Event}]};
handle_event(_, #ssh_msg_disconnect{description=Desc} = Msg, StateName, D0) ->
{disconnect, _, {{replies,Replies}, _}} =
ssh_connection:handle_msg(Msg, D0#data.connection_state, role(StateName)),
{Actions,D} = send_replies(Replies, D0),
disconnect_fun(Desc, D),
{stop_and_reply, {shutdown,Desc}, Actions, D};
handle_event(_, #ssh_msg_ignore{}, _, _) ->
keep_state_and_data;
handle_event(_, #ssh_msg_unimplemented{}, _, _) ->
keep_state_and_data;
handle_event(_, #ssh_msg_debug{} = Msg, _, D) ->
debug_fun(Msg, D),
keep_state_and_data;
handle_event(internal, Msg=#ssh_msg_global_request{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_request_success{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_request_failure{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_open{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_open_confirmation{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_open_failure{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_window_adjust{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_data{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_extended_data{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_eof{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_close{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_request{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_success{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(internal, Msg=#ssh_msg_channel_failure{}, StateName, D) ->
handle_connection_msg(Msg, StateName, D);
handle_event(cast, renegotiate, {connected,Role}, D) ->
{KeyInitMsg, SshPacket, Ssh} = ssh_transport:key_exchange_init_msg(D#data.ssh_params),
send_bytes(SshPacket, D),
timer:apply_after(?REKEY_TIMOUT, gen_statem, cast, [self(), renegotiate]),
{next_state, {kexinit,Role,renegotiate}, D#data{ssh_params = Ssh,
key_exchange_init_msg = KeyInitMsg}};
handle_event(cast, renegotiate, _, _) ->
%% Already in key-exchange so safe to ignore
timer:apply_after(?REKEY_TIMOUT, gen_statem, cast, [self(), renegotiate]), % FIXME: not here in original
keep_state_and_data;
%% Rekey due to sent data limit reached?
handle_event(cast, data_size, {connected,Role}, D) ->
{ok, [{send_oct,Sent0}]} = inet:getstat(D#data.socket, [send_oct]),
Sent = Sent0 - D#data.last_size_rekey,
MaxSent = proplists:get_value(rekey_limit, D#data.opts, 1024000000),
timer:apply_after(?REKEY_DATA_TIMOUT, gen_statem, cast, [self(), data_size]),
case Sent >= MaxSent of
true ->
{KeyInitMsg, SshPacket, Ssh} =
ssh_transport:key_exchange_init_msg(D#data.ssh_params),
send_bytes(SshPacket, D),
{next_state, {kexinit,Role,renegotiate}, D#data{ssh_params = Ssh,
key_exchange_init_msg = KeyInitMsg,
last_size_rekey = Sent0}};
_ ->
keep_state_and_data
end;
handle_event(cast, data_size, _, _) ->
%% Already in key-exchange so safe to ignore
timer:apply_after(?REKEY_DATA_TIMOUT, gen_statem, cast, [self(), data_size]), % FIXME: not here in original
keep_state_and_data;
handle_event(cast, _, StateName, _) when StateName /= {connected,server},
StateName /= {connected,client} ->
{keep_state_and_data, [postpone]};
handle_event(cast, {adjust_window,ChannelId,Bytes}, {connected,_}, D) ->
case ssh_channel:cache_lookup(cache(D), ChannelId) of
#channel{recv_window_size = WinSize,
recv_window_pending = Pending,
recv_packet_size = PktSize} = Channel
when (WinSize-Bytes) >= 2*PktSize ->
%% The peer can send at least two more *full* packet, no hurry.
ssh_channel:cache_update(cache(D),
Channel#channel{recv_window_pending = Pending + Bytes}),
keep_state_and_data;
#channel{recv_window_size = WinSize,
recv_window_pending = Pending,
remote_id = Id} = Channel ->
%% Now we have to update the window - we can't receive so many more pkts
ssh_channel:cache_update(cache(D),
Channel#channel{recv_window_size =
WinSize + Bytes + Pending,
recv_window_pending = 0}),
Msg = ssh_connection:channel_adjust_window_msg(Id, Bytes + Pending),
{keep_state, send_msg(Msg,D)};
undefined ->
keep_state_and_data
end;
handle_event(cast, {reply_request,success,ChannelId}, {connected,_}, D) ->
case ssh_channel:cache_lookup(cache(D), ChannelId) of
#channel{remote_id = RemoteId} ->
Msg = ssh_connection:channel_success_msg(RemoteId),
{keep_state, send_msg(Msg,D)};
undefined ->
keep_state_and_data
end;
handle_event(cast, {request,ChannelPid, ChannelId, Type, Data}, {connected,_}, D) ->
{keep_state, handle_request(ChannelPid, ChannelId, Type, Data, false, none, D)};
handle_event(cast, {request,ChannelId,Type,Data}, {connected,_}, D) ->
{keep_state, handle_request(ChannelId, Type, Data, false, none, D)};
handle_event(cast, {unknown,Data}, {connected,_}, D) ->
Msg = #ssh_msg_unimplemented{sequence = Data},
{keep_state, send_msg(Msg,D)};
%%% Previously handle_sync_event began here
handle_event({call,From}, get_print_info, StateName, D) ->
Reply =
try
{inet:sockname(D#data.socket),
inet:peername(D#data.socket)
}
of
{{ok,Local}, {ok,Remote}} ->
{{Local,Remote},io_lib:format("statename=~p",[StateName])};
_ ->
{{"-",0},"-"}
catch
_:_ ->
{{"?",0},"?"}
end,
{keep_state_and_data, [{reply,From,Reply}]};
handle_event({call,From}, {connection_info, Options}, _, D) ->
Info = ssh_info(Options, D, []),
{keep_state_and_data, [{reply,From,Info}]};
handle_event({call,From}, {channel_info,ChannelId,Options}, _, D) ->
case ssh_channel:cache_lookup(cache(D), ChannelId) of
#channel{} = Channel ->
Info = ssh_channel_info(Options, Channel, []),
{keep_state_and_data, [{reply,From,Info}]};
undefined ->
{keep_state_and_data, [{reply,From,[]}]}
end;
handle_event({call,From}, {info, all}, _, D) ->
Result = ssh_channel:cache_foldl(fun(Channel, Acc) ->
[Channel | Acc]
end,
[], cache(D)),
{keep_state_and_data, [{reply, From, {ok,Result}}]};
handle_event({call,From}, {info, ChannelPid}, _, D) ->
Result = ssh_channel:cache_foldl(
fun(Channel, Acc) when Channel#channel.user == ChannelPid ->
[Channel | Acc];
(_, Acc) ->
Acc
end, [], cache(D)),
{keep_state_and_data, [{reply, From, {ok,Result}}]};
handle_event({call,From}, stop, StateName, D0) ->
{disconnect, _Reason, {{replies, Replies}, Connection}} =
ssh_connection:handle_msg(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_BY_APPLICATION,
description = "User closed down connection"},
D0#data.connection_state,
role(StateName)),
{Repls,D} = send_replies(Replies, D0),
{stop_and_reply, normal, [{reply,From,ok}|Repls], D#data{connection_state=Connection}};
handle_event({call,_}, _, StateName, _) when StateName /= {connected,server},
StateName /= {connected,client} ->
{keep_state_and_data, [postpone]};
handle_event({call,From}, {request, ChannelPid, ChannelId, Type, Data, Timeout}, {connected,_}, D0) ->
D = handle_request(ChannelPid, ChannelId, Type, Data, true, From, D0),
%% Note reply to channel will happen later when reply is recived from peer on the socket
start_channel_request_timer(ChannelId, From, Timeout),
{keep_state, cache_request_idle_timer_check(D)};
handle_event({call,From}, {request, ChannelId, Type, Data, Timeout}, {connected,_}, D0) ->
D = handle_request(ChannelId, Type, Data, true, From, D0),
%% Note reply to channel will happen later when reply is recived from peer on the socket
start_channel_request_timer(ChannelId, From, Timeout),
{keep_state, cache_request_idle_timer_check(D)};
handle_event({call,From}, {global_request, Pid, _, _, _} = Request, {connected,_}, D0) ->
D1 = handle_global_request(Request, D0),
Channel = ssh_channel:cache_find(Pid, cache(D1)),
D = add_request(true, Channel#channel.local_id, From, D1),
{keep_state, D};
handle_event({call,From}, {data, ChannelId, Type, Data, Timeout}, {connected,_}, D0) ->
{{replies, Replies}, Connection} =
ssh_connection:channel_data(ChannelId, Type, Data, D0#data.connection_state, From),
{Repls,D} = send_replies(Replies, D0#data{connection_state = Connection}),
start_channel_request_timer(ChannelId, From, Timeout), % FIXME: No message exchange so why?
{keep_state, D, Repls};
handle_event({call,From}, {eof, ChannelId}, {connected,_}, D0) ->
case ssh_channel:cache_lookup(cache(D0), ChannelId) of
#channel{remote_id = Id, sent_close = false} ->
D = send_msg(ssh_connection:channel_eof_msg(Id), D0),
{keep_state, D, [{reply,From,ok}]};
_ ->
{keep_state, D0, [{reply,From,{error,closed}}]}
end;
handle_event({call,From},
{open, ChannelPid, Type, InitialWindowSize, MaxPacketSize, Data, Timeout},
{connected,_},
D0) ->
erlang:monitor(process, ChannelPid),
{ChannelId, D1} = new_channel_id(D0),
D2 = send_msg(ssh_connection:channel_open_msg(Type, ChannelId,
InitialWindowSize,
MaxPacketSize, Data),
D1),
ssh_channel:cache_update(cache(D2),
#channel{type = Type,
sys = "none",
user = ChannelPid,
local_id = ChannelId,
recv_window_size = InitialWindowSize,
recv_packet_size = MaxPacketSize,
send_buf = queue:new()
}),
D = add_request(true, ChannelId, From, D2),
start_channel_request_timer(ChannelId, From, Timeout),
{keep_state, cache_cancel_idle_timer(D)};
handle_event({call,From}, {send_window, ChannelId}, {connected,_}, D) ->
Reply = case ssh_channel:cache_lookup(cache(D), ChannelId) of
#channel{send_window_size = WinSize,
send_packet_size = Packsize} ->
{ok, {WinSize, Packsize}};
undefined ->
{error, einval}
end,
{keep_state_and_data, [{reply,From,Reply}]};
handle_event({call,From}, {recv_window, ChannelId}, {connected,_}, D) ->
Reply = case ssh_channel:cache_lookup(cache(D), ChannelId) of
#channel{recv_window_size = WinSize,
recv_packet_size = Packsize} ->
{ok, {WinSize, Packsize}};
undefined ->
{error, einval}
end,
{keep_state_and_data, [{reply,From,Reply}]};
handle_event({call,From}, {close, ChannelId}, {connected,_}, D0) ->
case ssh_channel:cache_lookup(cache(D0), ChannelId) of
#channel{remote_id = Id} = Channel ->
D1 = send_msg(ssh_connection:channel_close_msg(Id), D0),
ssh_channel:cache_update(cache(D1), Channel#channel{sent_close = true}),
{keep_state, cache_request_idle_timer_check(D1), [{reply,From,ok}]};
undefined ->
{keep_state_and_data, [{reply,From,ok}]}
end;
%%===== Reception of encrypted bytes, decryption and framing
handle_event(info, {Proto, Sock, Info}, {hello,_}, #data{socket = Sock,
transport_protocol = Proto}) ->
case Info of
"SSH-" ++ _ ->
{keep_state_and_data, [{next_event, internal, {version_exchange,Info}}]};
_ ->
{keep_state_and_data, [{next_event, internal, {info_line,Info}}]}
end;
handle_event(info, {Proto, Sock, NewData}, StateName, D0 = #data{socket = Sock,
transport_protocol = Proto}) ->
try ssh_transport:handle_packet_part(
D0#data.decrypted_data_buffer,
<<(D0#data.encrypted_data_buffer)/binary, NewData/binary>>,
D0#data.undecrypted_packet_length,
D0#data.ssh_params)
of
{packet_decrypted, DecryptedBytes, EncryptedDataRest, Ssh1} ->
D = D0#data{ssh_params =
Ssh1#ssh{recv_sequence = ssh_transport:next_seqnum(Ssh1#ssh.recv_sequence)},
decrypted_data_buffer = <<>>,
undecrypted_packet_length = undefined,
encrypted_data_buffer = EncryptedDataRest},
try
ssh_message:decode(set_kex_overload_prefix(DecryptedBytes,D))
of
Msg = #ssh_msg_kexinit{} ->
{keep_state, D, [{next_event, internal, {Msg,DecryptedBytes}},
{next_event, internal, prepare_next_packet}
]};
Msg ->
{keep_state, D, [{next_event, internal, Msg},
{next_event, internal, prepare_next_packet}
]}
catch
_C:_E ->
disconnect(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR,
description = "Encountered unexpected input"},
StateName, D)
end;
{get_more, DecryptedBytes, EncryptedDataRest, RemainingSshPacketLen, Ssh1} ->
%% Here we know that there are not enough bytes in
%% EncryptedDataRest to use. We must wait for more.
inet:setopts(Sock, [{active, once}]),
{keep_state, D0#data{encrypted_data_buffer = EncryptedDataRest,
decrypted_data_buffer = DecryptedBytes,
undecrypted_packet_length = RemainingSshPacketLen,
ssh_params = Ssh1}};
{bad_mac, Ssh1} ->
disconnect(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR,
description = "Bad mac"},
StateName, D0#data{ssh_params=Ssh1});
{error, {exceeds_max_size,PacketLen}} ->
disconnect(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR,
description = "Bad packet length "
++ integer_to_list(PacketLen)},
StateName, D0)
catch
_C:_E ->
disconnect(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR,
description = "Bad packet"},
StateName, D0)
end;
%%%====
handle_event(internal, prepare_next_packet, _, D) ->
Enough = erlang:max(8, D#data.ssh_params#ssh.decrypt_block_size),
case size(D#data.encrypted_data_buffer) of
Sz when Sz >= Enough ->
self() ! {D#data.transport_protocol, D#data.socket, <<>>};
_ ->
inet:setopts(D#data.socket, [{active, once}])
end,
keep_state_and_data;
handle_event(info, {CloseTag,Socket}, StateName,
D = #data{socket = Socket,
transport_close_tag = CloseTag}) ->
disconnect(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_BY_APPLICATION,
description = "Connection closed"},
StateName, D);
handle_event(info, {timeout, {_, From} = Request}, _,
#data{connection_state = #connection{requests = Requests} = C0} = D) ->
case lists:member(Request, Requests) of
true ->
%% A channel request is not answered in time. Answer {error,timeout}
%% to the caller
C = C0#connection{requests = lists:delete(Request, Requests)},
{keep_state, D#data{connection_state=C}, [{reply,From,{error,timeout}}]};
false ->
%% The request is answered - just ignore the timeout
keep_state_and_data
end;
%%% Handle that ssh channels user process goes down
handle_event(info, {'DOWN', _Ref, process, ChannelPid, _Reason}, _, D0) ->
{{replies, Replies}, D1} = handle_channel_down(ChannelPid, D0),
{Repls, D} = send_replies(Replies, D1),
{keep_state, D, Repls};
%%% So that terminate will be run when supervisor is shutdown
handle_event(info, {'EXIT', _Sup, Reason}, _, _) ->
{stop, {shutdown, Reason}};
handle_event(info, check_cache, _, D) ->
{keep_state, cache_check_set_idle_timer(D)};
handle_event(info, UnexpectedMessage, StateName, D = #data{ssh_params = Ssh}) ->
case unexpected_fun(UnexpectedMessage, D) of
report ->
Msg = lists:flatten(
io_lib:format(
"Unexpected message '~p' received in state '~p'\n"
"Role: ~p\n"
"Peer: ~p\n"
"Local Address: ~p\n", [UnexpectedMessage,
StateName,
Ssh#ssh.role,
Ssh#ssh.peer,
proplists:get_value(address, Ssh#ssh.opts)])),
error_logger:info_report(Msg),
keep_state_and_data;
skip ->
keep_state_and_data;
Other ->
Msg = lists:flatten(
io_lib:format("Call to fun in 'unexpectedfun' failed:~n"
"Return: ~p\n"
"Message: ~p\n"
"Role: ~p\n"
"Peer: ~p\n"
"Local Address: ~p\n", [Other,
UnexpectedMessage,
Ssh#ssh.role,
element(2,Ssh#ssh.peer),
proplists:get_value(address, Ssh#ssh.opts)]
)),
error_logger:error_report(Msg),
keep_state_and_data
end;
handle_event(internal, {disconnect,Msg,_Reason}, StateName, D) ->
disconnect(Msg, StateName, D);
handle_event(Type, Ev, StateName, D) ->
Descr =
case catch atom_to_list(element(1,Ev)) of
"ssh_msg_" ++_ when Type==internal ->
"Message in wrong state";
_ ->
"Internal error"
end,
disconnect(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR,
description = Descr},
StateName, D).
%%--------------------------------------------------------------------
-spec terminate(any(),
state_name(),
#data{}
) -> finalize_termination_result() .
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
terminate(normal, StateName, State) ->
finalize_termination(StateName, State);
terminate({shutdown,{init,Reason}}, StateName, State) ->
error_logger:info_report(io_lib:format("Erlang ssh in connection handler init: ~p~n",[Reason])),
finalize_termination(StateName, State);
terminate(shutdown, StateName, State0) ->
%% Terminated by supervisor
State = send_msg(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_BY_APPLICATION,
description = "Application shutdown"},
State0),
timer:sleep(400), %% FIXME!!! gen_tcp:shutdown instead
finalize_termination(StateName, State);
%% terminate({shutdown,Msg}, StateName, State0) when is_record(Msg,ssh_msg_disconnect)->
%% State = send_msg(Msg, State0),
%% timer:sleep(400), %% FIXME!!! gen_tcp:shutdown instead
%% finalize_termination(StateName, Msg, State);
terminate({shutdown,_R}, StateName, State) ->
finalize_termination(StateName, State);
terminate(Reason, StateName, State0) ->
%% Others, e.g undef, {badmatch,_}
log_error(Reason),
State = send_msg(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_BY_APPLICATION,
description = "Internal error"},
State0),
finalize_termination(StateName, State).
%%--------------------------------------------------------------------
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
format_status(normal, [_, _StateName, D]) ->
[{data, [{"State", D}]}];
format_status(terminate, [_, _StateName, D]) ->
DataPropList0 = fmt_stat_rec(record_info(fields, data), D,
[decrypted_data_buffer,
encrypted_data_buffer,
key_exchange_init_msg,
user_passwords,
opts,
inet_initial_recbuf_size]),
SshPropList = fmt_stat_rec(record_info(fields, ssh), D#data.ssh_params,
[c_keyinit,
s_keyinit,
send_mac_key,
send_mac_size,
recv_mac_key,
recv_mac_size,
encrypt_keys,
encrypt_ctx,
decrypt_keys,
decrypt_ctx,
compress_ctx,
decompress_ctx,
shared_secret,
exchanged_hash,
session_id,
keyex_key,
keyex_info,
available_host_keys]),
DataPropList = lists:keyreplace(ssh_params, 1, DataPropList0,
{ssh_params,SshPropList}),
[{data, [{"State", DataPropList}]}].
fmt_stat_rec(FieldNames, Rec, Exclude) ->
Values = tl(tuple_to_list(Rec)),
[P || {K,_} = P <- lists:zip(FieldNames, Values),
not lists:member(K, Exclude)].
%%--------------------------------------------------------------------
-spec code_change(term() | {down,term()},
state_name(),
#data{},
term()
) -> {gen_statem:callback_mode(), state_name(), #data{}}.
%% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
code_change(_OldVsn, StateName, State, _Extra) ->
{handle_event_function, StateName, State}.
%%====================================================================
%% Internal functions
%%====================================================================
%%--------------------------------------------------------------------
%% Starting
start_the_connection_child(UserPid, Role, Socket, Options) ->
Sups = proplists:get_value(supervisors, Options),
ConnectionSup = proplists:get_value(connection_sup, Sups),
Opts = [{supervisors, Sups}, {user_pid, UserPid} | proplists:get_value(ssh_opts, Options, [])],
{ok, Pid} = ssh_connection_sup:start_child(ConnectionSup, [Role, Socket, Opts]),
ok = socket_control(Socket, Pid, Options),
Pid.
%%--------------------------------------------------------------------
%% Stopping
-type finalize_termination_result() :: ok .
finalize_termination(_StateName, #data{transport_cb = Transport,
connection_state = Connection,
socket = Socket}) ->
case Connection of
#connection{system_supervisor = SysSup,
sub_system_supervisor = SubSysSup} when is_pid(SubSysSup) ->
ssh_system_sup:stop_subsystem(SysSup, SubSysSup);
_ ->
do_nothing
end,
(catch Transport:close(Socket)),
ok.
%%--------------------------------------------------------------------
%% "Invert" the Role
peer_role(client) -> server;
peer_role(server) -> client.
%%--------------------------------------------------------------------
%% StateName to Role
role({_,Role}) -> Role;
role({_,Role,_}) -> Role.
%%--------------------------------------------------------------------
%% Check the StateName to see if we are in the renegotiation phase
renegotiation({_,_,ReNeg}) -> ReNeg == renegotiation;
renegotiation(_) -> false.
%%--------------------------------------------------------------------
supported_host_keys(client, _, Options) ->
try
case proplists:get_value(public_key,
proplists:get_value(preferred_algorithms,Options,[])
) of
undefined ->
ssh_transport:default_algorithms(public_key);
L ->
L -- (L--ssh_transport:default_algorithms(public_key))
end
of
[] ->
{stop, {shutdown, "No public key algs"}};
Algs ->
[atom_to_list(A) || A<-Algs]
catch
exit:Reason ->
{stop, {shutdown, Reason}}
end;
supported_host_keys(server, KeyCb, Options) ->
[atom_to_list(A) || A <- proplists:get_value(public_key,
proplists:get_value(preferred_algorithms,Options,[]),
ssh_transport:default_algorithms(public_key)
),
available_host_key(KeyCb, A, Options)
].
%% Alg :: atom()
available_host_key(KeyCb, Alg, Opts) ->
element(1, catch KeyCb:host_key(Alg, Opts)) == ok.
send_msg(Msg, State=#data{ssh_params=Ssh0}) when is_tuple(Msg) ->
{Bytes, Ssh} = ssh_transport:ssh_packet(Msg, Ssh0),
send_bytes(Bytes, State),
State#data{ssh_params=Ssh}.
send_bytes(Bytes, #data{socket = Socket, transport_cb = Transport}) ->
Transport:send(Socket, Bytes).
handle_version({2, 0} = NumVsn, StrVsn, Ssh0) ->
Ssh = counterpart_versions(NumVsn, StrVsn, Ssh0),
{ok, Ssh};
handle_version(_,_,_) ->
not_supported.
string_version(#ssh{role = client, c_version = Vsn}) ->
Vsn;
string_version(#ssh{role = server, s_version = Vsn}) ->
Vsn.
cast(FsmPid, Event) ->
gen_statem:cast(FsmPid, Event).
call(FsmPid, Event) ->
call(FsmPid, Event, infinity).
call(FsmPid, Event, Timeout) ->
try gen_statem:call(FsmPid, Event, Timeout) of
{closed, _R} ->
{error, closed};
{killed, _R} ->
{error, closed};
Result ->
Result
catch
exit:{noproc, _R} ->
{error, closed};
exit:{normal, _R} ->
{error, closed};
exit:{{shutdown, _R},_} ->
{error, closed}
end.
handle_connection_msg(Msg, StateName, State0 =
#data{starter = User,
connection_state = Connection0,
event_queue = Qev0}) ->
Renegotiation = renegotiation(StateName),
Role = role(StateName),
try ssh_connection:handle_msg(Msg, Connection0, Role) of
{{replies, Replies}, Connection} ->
case StateName of
{connected,_} ->
{Repls, State} = send_replies(Replies,
State0#data{connection_state=Connection}),
{keep_state, State, Repls};
_ ->
{ConnReplies, Replies} =
lists:splitwith(fun not_connected_filter/1, Replies),
{Repls, State} = send_replies(Replies,
State0#data{event_queue = Qev0 ++ ConnReplies}),
{keep_state, State, Repls}
end;
{noreply, Connection} ->
{keep_state, State0#data{connection_state = Connection}};
{disconnect, Reason0, {{replies, Replies}, Connection}} ->
{Repls,State} = send_replies(Replies, State0#data{connection_state = Connection}),
case {Reason0,Role} of
{{_, Reason}, client} when ((StateName =/= {connected,client}) and (not Renegotiation)) ->
User ! {self(), not_connected, Reason};
_ ->
ok
end,
{stop, {shutdown,normal}, Repls, State#data{connection_state = Connection}}
catch
_:Error ->
{disconnect, _Reason, {{replies, Replies}, Connection}} =
ssh_connection:handle_msg(
#ssh_msg_disconnect{code = ?SSH_DISCONNECT_BY_APPLICATION,
description = "Internal error"},
Connection0, Role),
{Repls,State} = send_replies(Replies, State0#data{connection_state = Connection}),
{stop, {shutdown,Error}, Repls, State#data{connection_state = Connection}}
end.
set_kex_overload_prefix(Msg = <<?BYTE(Op),_/binary>>, #data{ssh_params=SshParams})
when Op == 30;
Op == 31
->
case catch atom_to_list(kex(SshParams)) of
"ecdh-sha2-" ++ _ ->
<<"ecdh",Msg/binary>>;
"diffie-hellman-group-exchange-" ++ _ ->
<<"dh_gex",Msg/binary>>;
"diffie-hellman-group" ++ _ ->
<<"dh",Msg/binary>>;
_ ->
Msg
end;
set_kex_overload_prefix(Msg, _) ->
Msg.
kex(#ssh{algorithms=#alg{kex=Kex}}) -> Kex;
kex(_) -> undefined.
cache(#data{connection_state=C}) -> C#connection.channel_cache.
%%%----------------------------------------------------------------
handle_request(ChannelPid, ChannelId, Type, Data, WantReply, From, D) ->
case ssh_channel:cache_lookup(cache(D), ChannelId) of
#channel{remote_id = Id} = Channel ->
update_sys(cache(D), Channel, Type, ChannelPid),
send_msg(ssh_connection:channel_request_msg(Id, Type, WantReply, Data),
add_request(WantReply, ChannelId, From, D));
undefined ->
D
end.
handle_request(ChannelId, Type, Data, WantReply, From, D) ->
case ssh_channel:cache_lookup(cache(D), ChannelId) of
#channel{remote_id = Id} ->
send_msg(ssh_connection:channel_request_msg(Id, Type, WantReply, Data),
add_request(WantReply, ChannelId, From, D));
undefined ->
D
end.
%%%----------------------------------------------------------------
handle_global_request({global_request, ChannelPid,
"tcpip-forward" = Type, WantReply,
<<?UINT32(IPLen),IP:IPLen/binary, ?UINT32(Port)>> = Data
},
D) ->
ssh_channel:cache_update(cache(D),
#channel{user = ChannelPid,
type = "forwarded-tcpip",
sys = none}),
Connection = ssh_connection:bind(IP, Port, ChannelPid, D#data.connection_state),
Msg = ssh_connection:global_request_msg(Type, WantReply, Data),
send_msg(Msg, D#data{connection_state = Connection});
handle_global_request({global_request, _Pid, "cancel-tcpip-forward" = Type,
WantReply, <<?UINT32(IPLen),
IP:IPLen/binary, ?UINT32(Port)>> = Data},
#data{connection_state = Connection0} = State) ->
Connection = ssh_connection:unbind(IP, Port, Connection0),
Msg = ssh_connection:global_request_msg(Type, WantReply, Data),
send_msg(Msg, State#data{connection_state = Connection});
handle_global_request({global_request, _, "cancel-tcpip-forward" = Type,
WantReply, Data}, State) ->
Msg = ssh_connection:global_request_msg(Type, WantReply, Data),
send_msg(Msg, State).
%%%----------------------------------------------------------------
handle_channel_down(ChannelPid, D) ->
ssh_channel:cache_foldl(
fun(Channel, Acc) when Channel#channel.user == ChannelPid ->
ssh_channel:cache_delete(cache(D),
Channel#channel.local_id),
Acc;
(_,Acc) ->
Acc
end, [], cache(D)),
{{replies, []}, cache_check_set_idle_timer(D)}.
update_sys(Cache, Channel, Type, ChannelPid) ->
ssh_channel:cache_update(Cache,
Channel#channel{sys = Type, user = ChannelPid}).
add_request(false, _ChannelId, _From, State) ->
State;
add_request(true, ChannelId, From, #data{connection_state =
#connection{requests = Requests0} =
Connection} = State) ->
Requests = [{ChannelId, From} | Requests0],
State#data{connection_state = Connection#connection{requests = Requests}}.
new_channel_id(#data{connection_state = #connection{channel_id_seed = Id} =
Connection}
= State) ->
{Id, State#data{connection_state =
Connection#connection{channel_id_seed = Id + 1}}}.
%%%----------------------------------------------------------------
%% %%% This server/client has decided to disconnect via the state machine:
disconnect(Msg=#ssh_msg_disconnect{description=Description}, _StateName, State0) ->
State = send_msg(Msg, State0),
disconnect_fun(Description, State),
timer:sleep(400),
{stop, {shutdown,Description}, State}.
%%%----------------------------------------------------------------
counterpart_versions(NumVsn, StrVsn, #ssh{role = server} = Ssh) ->
Ssh#ssh{c_vsn = NumVsn , c_version = StrVsn};
counterpart_versions(NumVsn, StrVsn, #ssh{role = client} = Ssh) ->
Ssh#ssh{s_vsn = NumVsn , s_version = StrVsn}.
ssh_info([], _State, Acc) ->
Acc;
ssh_info([client_version | Rest], #data{ssh_params = #ssh{c_vsn = IntVsn,
c_version = StringVsn}} = State, Acc) ->
ssh_info(Rest, State, [{client_version, {IntVsn, StringVsn}} | Acc]);
ssh_info([server_version | Rest], #data{ssh_params =#ssh{s_vsn = IntVsn,
s_version = StringVsn}} = State, Acc) ->
ssh_info(Rest, State, [{server_version, {IntVsn, StringVsn}} | Acc]);
ssh_info([peer | Rest], #data{ssh_params = #ssh{peer = Peer}} = State, Acc) ->
ssh_info(Rest, State, [{peer, Peer} | Acc]);
ssh_info([sockname | Rest], #data{socket = Socket} = State, Acc) ->
{ok, SockName} = inet:sockname(Socket),
ssh_info(Rest, State, [{sockname, SockName}|Acc]);
ssh_info([user | Rest], #data{auth_user = User} = State, Acc) ->
ssh_info(Rest, State, [{user, User}|Acc]);
ssh_info([ _ | Rest], State, Acc) ->
ssh_info(Rest, State, Acc).
ssh_channel_info([], _, Acc) ->
Acc;
ssh_channel_info([recv_window | Rest], #channel{recv_window_size = WinSize,
recv_packet_size = Packsize
} = Channel, Acc) ->
ssh_channel_info(Rest, Channel, [{recv_window, {{win_size, WinSize},
{packet_size, Packsize}}} | Acc]);
ssh_channel_info([send_window | Rest], #channel{send_window_size = WinSize,
send_packet_size = Packsize
} = Channel, Acc) ->
ssh_channel_info(Rest, Channel, [{send_window, {{win_size, WinSize},
{packet_size, Packsize}}} | Acc]);
ssh_channel_info([ _ | Rest], Channel, Acc) ->
ssh_channel_info(Rest, Channel, Acc).
log_error(Reason) ->
Report = io_lib:format("Erlang ssh connection handler failed with reason:~n"
" ~p~n"
"Stacktrace:~n"
" ~p~n",
[Reason, erlang:get_stacktrace()]),
error_logger:error_report(Report).
%%%----------------------------------------------------------------
not_connected_filter({connection_reply, _Data}) -> true;
not_connected_filter(_) -> false.
%%%----------------------------------------------------------------
send_replies(Repls, State) ->
lists:foldl(fun get_repl/2,
{[],State},
Repls).
get_repl({connection_reply,Msg}, {CallRepls,S}) ->
{CallRepls, send_msg(Msg,S)};
get_repl({channel_data,undefined,_Data}, Acc) ->
Acc;
get_repl({channel_data,Pid,Data}, Acc) ->
Pid ! {ssh_cm, self(), Data},
Acc;
get_repl({channel_request_reply,From,Data}, {CallRepls,S}) ->
{[{reply,From,Data}|CallRepls], S};
get_repl({flow_control,Cache,Channel,From,Msg}, {CallRepls,S}) ->
ssh_channel:cache_update(Cache, Channel#channel{flow_control = undefined}),
{[{reply,From,Msg}|CallRepls], S};
get_repl({flow_control,From,Msg}, {CallRepls,S}) ->
{[{reply,From,Msg}|CallRepls], S};
get_repl(noreply, Acc) ->
Acc;
get_repl(X, Acc) ->
exit({get_repl,X,Acc}).
%%%----------------------------------------------------------------
disconnect_fun({disconnect,Msg}, D) ->
disconnect_fun(Msg, D);
disconnect_fun(Reason, #data{opts=Opts}) ->
case proplists:get_value(disconnectfun, Opts) of
undefined ->
ok;
Fun ->
catch Fun(Reason)
end.
unexpected_fun(UnexpectedMessage, #data{opts = Opts,
ssh_params = #ssh{peer = {_,Peer} }
} ) ->
case proplists:get_value(unexpectedfun, Opts) of
undefined ->
report;
Fun ->
catch Fun(UnexpectedMessage, Peer)
end.
debug_fun(#ssh_msg_debug{always_display = Display,
message = DbgMsg,
language = Lang},
#data{opts = Opts}) ->
case proplists:get_value(ssh_msg_debug_fun, Opts) of
undefined ->
ok;
Fun ->
catch Fun(self(), Display, DbgMsg, Lang)
end.
connected_fun(User, Method, #data{ssh_params = #ssh{peer = {_,Peer}},
opts = Opts}) ->
case proplists:get_value(connectfun, Opts) of
undefined ->
ok;
Fun ->
catch Fun(User, Peer, Method)
end.
retry_fun(_, undefined, _) ->
ok;
retry_fun(User, Reason, #data{ssh_params = #ssh{opts = Opts,
peer = {_,Peer}
}}) ->
{Tag,Info} =
case Reason of
{error, Error} ->
{failfun, Error};
_ ->
{infofun, Reason}
end,
Fun = proplists:get_value(Tag, Opts, fun(_,_)-> ok end),
try erlang:fun_info(Fun, arity)
of
{arity, 2} -> %% Backwards compatible
catch Fun(User, Info);
{arity, 3} ->
catch Fun(User, Peer, Info);
_ ->
ok
catch
_:_ ->
ok
end.
%%%----------------------------------------------------------------
%%% Cache idle timer that closes the connection if there are no
%%% channels open for a while.
cache_init_idle_timer(D) ->
case proplists:get_value(idle_time, D#data.opts, infinity) of
infinity ->
D#data{idle_timer_value = infinity,
idle_timer_ref = infinity % A flag used later...
};
IdleTime ->
%% We dont want to set the timeout on first connect
D#data{idle_timer_value = IdleTime}
end.
cache_check_set_idle_timer(D = #data{idle_timer_ref = undefined,
idle_timer_value = IdleTime}) ->
%% No timer set - shall we set one?
case ssh_channel:cache_info(num_entries, cache(D)) of
0 when IdleTime == infinity ->
%% No. Meaningless to set a timer that fires in an infinite time...
D;
0 ->
%% Yes, we'll set one since the cache is empty and it should not
%% be that for a specified time
D#data{idle_timer_ref =
erlang:send_after(IdleTime, self(), {'EXIT',[],"Timeout"})};
_ ->
%% No - there are entries in the cache
D
end;
cache_check_set_idle_timer(D) ->
%% There is already a timer set or the timeout time is infinite
D.
cache_cancel_idle_timer(D) ->
case D#data.idle_timer_ref of
infinity ->
%% The timer is not activated
D;
undefined ->
%% The timer is already cancelled
D;
TimerRef ->
%% The timer is active
erlang:cancel_timer(TimerRef),
D#data{idle_timer_ref = undefined}
end.
cache_request_idle_timer_check(D = #data{idle_timer_value = infinity}) ->
D;
cache_request_idle_timer_check(D = #data{idle_timer_value = IdleTime}) ->
erlang:send_after(IdleTime, self(), check_cache),
D.
%%%----------------------------------------------------------------
start_channel_request_timer(_,_, infinity) ->
ok;
start_channel_request_timer(Channel, From, Time) ->
erlang:send_after(Time, self(), {timeout, {Channel, From}}).
%%%----------------------------------------------------------------
%%% Connection start and initalization helpers
socket_control(Socket, Pid, Options) ->
{_, TransportCallback, _} = % For example {_,gen_tcp,_}
proplists:get_value(transport, Options, ?DefaultTransport),
case TransportCallback:controlling_process(Socket, Pid) of
ok ->
gen_statem:cast(Pid, socket_control);
{error, Reason} ->
{error, Reason}
end.
handshake(Pid, Ref, Timeout) ->
receive
ssh_connected ->
erlang:demonitor(Ref),
{ok, Pid};
{Pid, not_connected, Reason} ->
{error, Reason};
{Pid, user_password} ->
Pass = io:get_password(),
Pid ! Pass,
handshake(Pid, Ref, Timeout);
{Pid, question} ->
Answer = io:get_line(""),
Pid ! Answer,
handshake(Pid, Ref, Timeout);
{'DOWN', _, process, Pid, {shutdown, Reason}} ->
{error, Reason};
{'DOWN', _, process, Pid, Reason} ->
{error, Reason}
after Timeout ->
stop(Pid),
{error, timeout}
end.