summaryrefslogtreecommitdiff
path: root/lib/ssh/src/ssh_fsm_userauth_server.erl
blob: 74642a809875c84f932ae329617528d47ecca70c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2008-2020. 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_fsm_userauth_server).

-include("ssh.hrl").
-include("ssh_transport.hrl").
-include("ssh_auth.hrl").
-include("ssh_connect.hrl").

-include("ssh_fsm.hrl").

%%====================================================================
%%% Exports
%%====================================================================

%%% Behaviour callbacks
-export([callback_mode/0, handle_event/4, terminate/3,
	 format_status/2, code_change/4]).

%%====================================================================
%% gen_statem callbacks
%%====================================================================

callback_mode() ->
    [handle_event_function,
     state_enter].

%%--------------------------------------------------------------------

%%% ######## {userauth, server} ####
%%---- userauth request to server
handle_event(internal, 
	     Msg = #ssh_msg_userauth_request{service = ServiceName,
                                             method = Method},
	     StateName = {userauth,server},
	     D0 = #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),
            D = ssh_connection_handler:send_msg(Reply, D0#data{ssh_params = Ssh}),
	    {keep_state, D};
	
	{"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, Ssh1}} ->
                            D = connected_state(Reply, Ssh1, User, Method, D0),
                            {next_state, {connected,server}, D, {change_callback_module,ssh_connection_handler}};
			{not_authorized, {User, Reason}, {Reply, Ssh}} when Method == "keyboard-interactive" ->
			    retry_fun(User, Reason, D0),
                            D = ssh_connection_handler:send_msg(Reply, D0#data{ssh_params = Ssh}),
			    {next_state, {userauth_keyboard_interactive,server}, D};
			{not_authorized, {User, Reason}, {Reply, Ssh}} ->
			    retry_fun(User, Reason, D0),
                            D = ssh_connection_handler:send_msg(Reply, D0#data{ssh_params = Ssh}),
			    {keep_state, D}
		    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" ->
            {Shutdown, D} =  
                ?send_disconnect(?SSH_DISCONNECT_SERVICE_NOT_AVAILABLE,
                                 io_lib:format("Unknown service: ~p",[ServiceName]),
                                 StateName, D0),
            {stop, Shutdown, D}
    end;

handle_event(internal, #ssh_msg_userauth_info_response{} = Msg, {userauth_keyboard_interactive, server}, D0) ->
    case ssh_auth:handle_userauth_info_response(Msg, D0#data.ssh_params) of
	{authorized, User, {Reply, Ssh1}} ->
            D = connected_state(Reply, Ssh1, User, "keyboard-interactive", D0),
            {next_state, {connected,server}, D, {change_callback_module,ssh_connection_handler}};
	{not_authorized, {User, Reason}, {Reply, Ssh}} ->
	    retry_fun(User, Reason, D0),
            D = ssh_connection_handler:send_msg(Reply, D0#data{ssh_params = Ssh}),
	    {next_state, {userauth,server}, D};

	{authorized_but_one_more, _User,  {Reply, Ssh}} ->
            D = ssh_connection_handler:send_msg(Reply, D0#data{ssh_params = Ssh}),
	    {next_state, {userauth_keyboard_interactive_extra,server}, D}
    end;

handle_event(internal, #ssh_msg_userauth_info_response{} = Msg, {userauth_keyboard_interactive_extra, server}, D0) ->
    {authorized, User, {Reply, Ssh1}} =
        ssh_auth:handle_userauth_info_response({extra,Msg}, D0#data.ssh_params),
    D = connected_state(Reply, Ssh1, User, "keyboard-interactive", D0),
    {next_state, {connected,server}, D, {change_callback_module,ssh_connection_handler}};


%%% ######## UNHANDLED EVENT!
handle_event(Type, Event, StateName, D) ->
    ssh_connection_handler:handle_event(Type, Event, StateName, D).

%%--------------------------------------------------------------------
format_status(A, B) ->
    ssh_connection_handler:format_status(A, B).

%%--------------------------------------------------------------------
terminate(Reason, StateName, D) ->
    ssh_connection_handler:terminate(Reason, StateName, D).

%%--------------------------------------------------------------------
code_change(_OldVsn, StateName, State, _Extra) ->
    {ok, StateName, State}.

%%====================================================================
%% Internal functions
%%====================================================================

connected_state(Reply, Ssh1, User, Method, D0) ->
    D1 = #data{ssh_params=Ssh} =
        ssh_connection_handler:send_msg(Reply, D0#data{ssh_params = Ssh1}),
    ssh_connection_handler:handshake(ssh_connected, D1),
    connected_fun(User, Method, D1),
    D1#data{auth_user=User,
            %% Note: authenticated=true MUST NOT be sent
            %% before send_msg!
            ssh_params = Ssh#ssh{authenticated = true}}.


connected_fun(User, Method, #data{ssh_params = #ssh{peer = {_,Peer}}} = D) ->
    ?CALL_FUN(connectfun,D)(User, Peer, Method).


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 = ?GET_OPT(Tag, Opts),
    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.