diff options
Diffstat (limited to 'lib/ssh/src/ssh_auth.erl')
| -rw-r--r-- | lib/ssh/src/ssh_auth.erl | 495 |
1 files changed, 285 insertions, 210 deletions
diff --git a/lib/ssh/src/ssh_auth.erl b/lib/ssh/src/ssh_auth.erl index 49eec8072f..ac64a7bf14 100644 --- a/lib/ssh/src/ssh_auth.erl +++ b/lib/ssh/src/ssh_auth.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 2008-2016. All Rights Reserved. +%% Copyright Ericsson AB 2008-2017. All Rights Reserved. %% %% Licensed under the Apache License, Version 2.0 (the "License"); %% you may not use this file except in compliance with the License. @@ -28,57 +28,87 @@ -include("ssh_auth.hrl"). -include("ssh_transport.hrl"). --export([publickey_msg/1, password_msg/1, keyboard_interactive_msg/1, +-export([get_public_key/2, + publickey_msg/1, password_msg/1, keyboard_interactive_msg/1, service_request_msg/1, init_userauth_request_msg/1, userauth_request_msg/1, handle_userauth_request/3, - handle_userauth_info_request/3, handle_userauth_info_response/2 + handle_userauth_info_request/2, handle_userauth_info_response/2 ]). %%-------------------------------------------------------------------- %%% Internal application API %%-------------------------------------------------------------------- -publickey_msg([Alg, #ssh{user = User, - session_id = SessionId, - service = Service, - opts = Opts} = Ssh]) -> - Hash = sha, %% Maybe option?! - KeyCb = proplists:get_value(key_cb, Opts, ssh_file), - case KeyCb:user_key(Alg, Opts) of - {ok, PrivKey} -> - StrAlgo = atom_to_list(Alg), - case encode_public_key(StrAlgo, ssh_transport:extract_public_key(PrivKey)) of - not_ok -> - not_ok; - PubKeyBlob -> - SigData = build_sig_data(SessionId, - User, Service, PubKeyBlob, StrAlgo), - Sig = ssh_transport:sign(SigData, Hash, PrivKey), - SigBlob = list_to_binary([?string(StrAlgo), ?binary(Sig)]), - ssh_transport:ssh_packet( - #ssh_msg_userauth_request{user = User, - service = Service, - method = "publickey", - data = [?TRUE, - ?string(StrAlgo), - ?binary(PubKeyBlob), - ?binary(SigBlob)]}, - Ssh) - end; - _Error -> - not_ok +%%%---------------------------------------------------------------- +userauth_request_msg(#ssh{userauth_methods = ServerMethods, + userauth_supported_methods = UserPrefMethods, % Note: this is not documented as supported for clients + userauth_preference = ClientMethods0 + } = Ssh0) -> + case sort_select_mthds(ClientMethods0, UserPrefMethods, ServerMethods) of + [] -> + Msg = #ssh_msg_disconnect{code = ?SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE, + description = "Unable to connect using the available authentication methods", + language = "en"}, + {disconnect, Msg, ssh_transport:ssh_packet(Msg, Ssh0)}; + + [{Pref,Module,Function,Args} | Prefs] -> + Ssh = case Pref of + "keyboard-interactive" -> Ssh0; + _ -> Ssh0#ssh{userauth_preference = Prefs} + end, + case Module:Function(Args ++ [Ssh]) of + {not_ok, Ssh1} -> + userauth_request_msg(Ssh1#ssh{userauth_preference = Prefs}); + Result -> + {Pref,Result} + end end. + + +sort_select_mthds(Clients, undefined, Servers) -> + %% User has not expressed an opinion via option "auth_methods", use the server's prefs + sort_select_mthds1(Clients, Servers, string:tokens(?SUPPORTED_AUTH_METHODS,",")); + +sort_select_mthds(Clients, Users0, Servers0) -> + %% The User has an opinion, use the intersection of that and the Servers whishes but + %% in the Users order + sort_select_mthds1(Clients, string:tokens(Users0,","), Servers0). + + +sort_select_mthds1(Clients, Users0, Servers0) -> + Servers = unique(Servers0), + Users = unique(Users0), + [C || Key <- Users, + lists:member(Key, Servers), + C <- Clients, + element(1,C) == Key]. + +unique(L) -> + lists:reverse( + lists:foldl(fun(E,Acc) -> + case lists:member(E,Acc) of + true -> Acc; + false -> [E|Acc] + end + end, [], L)). + + +%%%---- userauth_request_msg "callbacks" password_msg([#ssh{opts = Opts, io_cb = IoCb, - user = User, service = Service} = Ssh]) -> - Password = case proplists:get_value(password, Opts) of - undefined -> - user_interaction(IoCb, Ssh); - PW -> - PW - end, + user = User, service = Service} = Ssh0]) -> + {Password,Ssh} = + case ?GET_OPT(password, Opts) of + undefined when IoCb == ssh_no_io -> + {not_ok, Ssh0}; + undefined -> + {IoCb:read_password("ssh password: ",Opts), Ssh0}; + PW -> + %% If "password" option is given it should not be tried again + {PW, Ssh0#ssh{opts = ?PUT_OPT({password,not_ok}, Opts)}} + end, case Password of not_ok -> - not_ok; + {not_ok, Ssh}; _ -> ssh_transport:ssh_packet( #ssh_msg_userauth_request{user = User, @@ -90,84 +120,100 @@ password_msg([#ssh{opts = Opts, io_cb = IoCb, Ssh) end. -user_interaction(ssh_no_io, _) -> - not_ok; -user_interaction(IoCb, Ssh) -> - IoCb:read_password("ssh password: ", Ssh). - - %% See RFC 4256 for info on keyboard-interactive keyboard_interactive_msg([#ssh{user = User, + opts = Opts, service = Service} = Ssh]) -> - ssh_transport:ssh_packet( - #ssh_msg_userauth_request{user = User, - service = Service, - method = "keyboard-interactive", - data = << ?STRING(<<"">>), - ?STRING(<<>>) >> }, - Ssh). + case ?GET_OPT(password, Opts) of + not_ok -> + {not_ok,Ssh}; % No need to use a failed pwd once more + _ -> + ssh_transport:ssh_packet( + #ssh_msg_userauth_request{user = User, + service = Service, + method = "keyboard-interactive", + data = << ?STRING(<<"">>), + ?STRING(<<>>) >> }, + Ssh) + end. + +get_public_key(SigAlg, #ssh{opts = Opts}) -> + KeyAlg = key_alg(SigAlg), + {KeyCb,KeyCbOpts} = ?GET_OPT(key_cb, Opts), + UserOpts = ?GET_OPT(user_options, Opts), + case KeyCb:user_key(KeyAlg, [{key_cb_private,KeyCbOpts}|UserOpts]) of + {ok, PrivKey} -> + try + Key = ssh_transport:extract_public_key(PrivKey), + public_key:ssh_encode(Key, ssh2_pubkey) + of + PubKeyBlob -> {ok,{PrivKey,PubKeyBlob}} + catch + _:_ -> + not_ok + end; + _Error -> + not_ok + end. + + +publickey_msg([SigAlg, #ssh{user = User, + session_id = SessionId, + service = Service} = Ssh]) -> + case get_public_key(SigAlg, Ssh) of + {ok, {PrivKey,PubKeyBlob}} -> + SigAlgStr = atom_to_list(SigAlg), + SigData = build_sig_data(SessionId, User, Service, + PubKeyBlob, SigAlgStr), + Hash = ssh_transport:sha(SigAlg), + Sig = ssh_transport:sign(SigData, Hash, PrivKey), + SigBlob = list_to_binary([?string(SigAlgStr), + ?binary(Sig)]), + ssh_transport:ssh_packet( + #ssh_msg_userauth_request{user = User, + service = Service, + method = "publickey", + data = [?TRUE, + ?string(SigAlgStr), + ?binary(PubKeyBlob), + ?binary(SigBlob)]}, + Ssh); + _ -> + {not_ok, Ssh} + end. + +%%%---------------------------------------------------------------- service_request_msg(Ssh) -> ssh_transport:ssh_packet(#ssh_msg_service_request{name = "ssh-userauth"}, Ssh#ssh{service = "ssh-userauth"}). +%%%---------------------------------------------------------------- init_userauth_request_msg(#ssh{opts = Opts} = Ssh) -> - case user_name(Opts) of - {ok, User} -> - Msg = #ssh_msg_userauth_request{user = User, - service = "ssh-connection", - method = "none", - data = <<>>}, - Algs0 = proplists:get_value(pref_public_key_algs, Opts, ?SUPPORTED_USER_KEYS), - %% The following line is not strictly correct. The call returns the - %% supported HOST key types while we are interested in USER keys. However, - %% they "happens" to be the same (for now). This could change.... - %% There is no danger as long as the set of user keys is a subset of the set - %% of host keys. - CryptoSupported = ssh_transport:supported_algorithms(public_key), - Algs = [A || A <- Algs0, - lists:member(A, CryptoSupported)], - - Prefs = method_preference(Algs), - ssh_transport:ssh_packet(Msg, Ssh#ssh{user = User, - userauth_preference = Prefs, - userauth_methods = none, - service = "ssh-connection"}); - {error, no_user} -> + %% Client side + case ?GET_OPT(user, Opts) of + undefined -> ErrStr = "Could not determine the users name", ssh_connection_handler:disconnect( #ssh_msg_disconnect{code = ?SSH_DISCONNECT_ILLEGAL_USER_NAME, - description = ErrStr}) - end. - -userauth_request_msg(#ssh{userauth_preference = []} = Ssh) -> - Msg = #ssh_msg_disconnect{code = - ?SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE, - description = "Unable to connect using the available" - " authentication methods", - language = "en"}, - {disconnect, Msg, ssh_transport:ssh_packet(Msg, Ssh)}; - -userauth_request_msg(#ssh{userauth_methods = Methods, - userauth_preference = [{Pref, Module, - Function, Args} | Prefs]} - = Ssh0) -> - Ssh = Ssh0#ssh{userauth_preference = Prefs}, - case lists:member(Pref, Methods) of - true -> - case Module:Function(Args ++ [Ssh]) of - not_ok -> - userauth_request_msg(Ssh); - Result -> - {Pref,Result} - end; - false -> - userauth_request_msg(Ssh) + description = ErrStr}); + + User -> + ssh_transport:ssh_packet( + #ssh_msg_userauth_request{user = User, + service = "ssh-connection", + method = "none", + data = <<>>}, + Ssh#ssh{user = User, + userauth_preference = method_preference(Ssh#ssh.userauth_pubkeys), + userauth_methods = none, + service = "ssh-connection"} + ) end. - -handle_userauth_request(#ssh_msg_service_request{name = - Name = "ssh-userauth"}, +%%%---------------------------------------------------------------- +%%% called by server +handle_userauth_request(#ssh_msg_service_request{name = Name = "ssh-userauth"}, _, Ssh) -> {ok, ssh_transport:ssh_packet(#ssh_msg_service_accept{name = Name}, Ssh#ssh{service = "ssh-connection"})}; @@ -223,32 +269,52 @@ handle_userauth_request(#ssh_msg_userauth_request{user = User, handle_userauth_request(#ssh_msg_userauth_request{user = User, service = "ssh-connection", method = "publickey", - data = Data}, - SessionId, + data = <<?BYTE(?FALSE), + ?UINT32(ALen), BAlg:ALen/binary, + ?UINT32(KLen), KeyBlob:KLen/binary, + _/binary + >> + }, + _SessionId, #ssh{opts = Opts, userauth_supported_methods = Methods} = Ssh) -> - <<?BYTE(HaveSig), ?UINT32(ALen), BAlg:ALen/binary, - ?UINT32(KLen), KeyBlob:KLen/binary, SigWLen/binary>> = Data, - Alg = binary_to_list(BAlg), - case HaveSig of - ?TRUE -> - case verify_sig(SessionId, User, "ssh-connection", Alg, - KeyBlob, SigWLen, Opts) of - true -> - {authorized, User, - ssh_transport:ssh_packet( - #ssh_msg_userauth_success{}, Ssh)}; - false -> - {not_authorized, {User, undefined}, - ssh_transport:ssh_packet(#ssh_msg_userauth_failure{ - authentications = Methods, - partial_success = false}, Ssh)} - end; - ?FALSE -> + + case pre_verify_sig(User, KeyBlob, Opts) of + true -> {not_authorized, {User, undefined}, ssh_transport:ssh_packet( - #ssh_msg_userauth_pk_ok{algorithm_name = Alg, - key_blob = KeyBlob}, Ssh)} + #ssh_msg_userauth_pk_ok{algorithm_name = binary_to_list(BAlg), + key_blob = KeyBlob}, Ssh)}; + false -> + {not_authorized, {User, undefined}, + ssh_transport:ssh_packet(#ssh_msg_userauth_failure{ + authentications = Methods, + partial_success = false}, Ssh)} + end; + +handle_userauth_request(#ssh_msg_userauth_request{user = User, + service = "ssh-connection", + method = "publickey", + data = <<?BYTE(?TRUE), + ?UINT32(ALen), BAlg:ALen/binary, + ?UINT32(KLen), KeyBlob:KLen/binary, + SigWLen/binary>> + }, + SessionId, + #ssh{opts = Opts, + userauth_supported_methods = Methods} = Ssh) -> + + case verify_sig(SessionId, User, "ssh-connection", + BAlg, KeyBlob, SigWLen, Opts) of + true -> + {authorized, User, + ssh_transport:ssh_packet( + #ssh_msg_userauth_success{}, Ssh)}; + false -> + {not_authorized, {User, undefined}, + ssh_transport:ssh_packet(#ssh_msg_userauth_failure{ + authentications = Methods, + partial_success = false}, Ssh)} end; handle_userauth_request(#ssh_msg_userauth_request{user = User, @@ -283,7 +349,7 @@ handle_userauth_request(#ssh_msg_userauth_request{user = User, false}, {Name, Instruction, Prompt, Echo} = - case proplists:get_value(auth_method_kb_interactive_data, Opts) of + case ?GET_OPT(auth_method_kb_interactive_data, Opts) of undefined -> Default; {_,_,_,_}=V -> @@ -319,31 +385,54 @@ handle_userauth_request(#ssh_msg_userauth_request{user = User, partial_success = false}, Ssh)}. - -handle_userauth_info_request( - #ssh_msg_userauth_info_request{name = Name, - instruction = Instr, - num_prompts = NumPrompts, - data = Data}, IoCb, - #ssh{opts = Opts} = Ssh) -> +%%%---------------------------------------------------------------- +%%% keyboard-interactive client +handle_userauth_info_request(#ssh_msg_userauth_info_request{name = Name, + instruction = Instr, + num_prompts = NumPrompts, + data = Data}, + #ssh{opts = Opts, + io_cb = IoCb + } = Ssh) -> PromptInfos = decode_keyboard_interactive_prompts(NumPrompts,Data), - Responses = keyboard_interact_get_responses(IoCb, Opts, - Name, Instr, PromptInfos), - {ok, - ssh_transport:ssh_packet( - #ssh_msg_userauth_info_response{num_responses = NumPrompts, - data = Responses}, Ssh)}. + case keyboard_interact_get_responses(IoCb, Opts, Name, Instr, PromptInfos) of + not_ok -> + not_ok; + Responses -> + {ok, + ssh_transport:ssh_packet( + #ssh_msg_userauth_info_response{num_responses = NumPrompts, + data = Responses}, Ssh)} + end. +%%%---------------------------------------------------------------- +%%% keyboard-interactive server handle_userauth_info_response(#ssh_msg_userauth_info_response{num_responses = 1, data = <<?UINT32(Sz), Password:Sz/binary>>}, #ssh{opts = Opts, kb_tries_left = KbTriesLeft, user = User, userauth_supported_methods = Methods} = Ssh) -> + SendOneEmpty = + (?GET_OPT(tstflg,Opts) == one_empty) + orelse + proplists:get_value(one_empty, ?GET_OPT(tstflg,Opts), false), + case check_password(User, unicode:characters_to_list(Password), Opts, Ssh) of + {true,Ssh1} when SendOneEmpty==true -> + Msg = #ssh_msg_userauth_info_request{name = "", + instruction = "", + language_tag = "", + num_prompts = 0, + data = <<?BOOLEAN(?FALSE)>> + }, + {authorized_but_one_more, User, + ssh_transport:ssh_packet(Msg, Ssh1)}; + {true,Ssh1} -> {authorized, User, ssh_transport:ssh_packet(#ssh_msg_userauth_success{}, Ssh1)}; + {false,Ssh1} -> {not_authorized, {User, {error,"Bad user or password"}}, ssh_transport:ssh_packet(#ssh_msg_userauth_failure{ @@ -353,6 +442,11 @@ handle_userauth_info_response(#ssh_msg_userauth_info_response{num_responses = 1, )} end; +handle_userauth_info_response({extra,#ssh_msg_userauth_info_response{}}, + #ssh{user = User} = Ssh) -> + {authorized, User, + ssh_transport:ssh_packet(#ssh_msg_userauth_success{}, Ssh)}; + handle_userauth_info_response(#ssh_msg_userauth_info_response{}, _Auth) -> ssh_connection_handler:disconnect( @@ -364,41 +458,17 @@ handle_userauth_info_response(#ssh_msg_userauth_info_response{}, %%-------------------------------------------------------------------- %%% Internal functions %%-------------------------------------------------------------------- -method_preference(Algs) -> - lists:foldr(fun(A, Acc) -> - [{"publickey", ?MODULE, publickey_msg, [A]} | Acc] - end, - [{"password", ?MODULE, password_msg, []}, - {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []}, - {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []}, - {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []}, - {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []}, - {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []}, - {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []} - ], - Algs). - -user_name(Opts) -> - Env = case os:type() of - {win32, _} -> - "USERNAME"; - {unix, _} -> - "LOGNAME" - end, - case proplists:get_value(user, Opts, os:getenv(Env)) of - false -> - case os:getenv("USER") of - false -> - {error, no_user}; - User -> - {ok, User} - end; - User -> - {ok, User} - end. +method_preference(SigKeyAlgs) -> + %% PubKeyAlgs: List of user (client) public key algorithms to try to use. + %% All of the acceptable algorithms is the default values. + PubKeyDefs = [{"publickey", ?MODULE, publickey_msg, [A]} || A <- SigKeyAlgs], + NonPKmethods = [{"password", ?MODULE, password_msg, []}, + {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []} + ], + PubKeyDefs ++ NonPKmethods. check_password(User, Password, Opts, Ssh) -> - case proplists:get_value(pwdfun, Opts) of + case ?GET_OPT(pwdfun, Opts) of undefined -> Static = get_password_option(Opts, User), {Password == Static, Ssh}; @@ -428,25 +498,37 @@ check_password(User, Password, Opts, Ssh) -> end. get_password_option(Opts, User) -> - Passwords = proplists:get_value(user_passwords, Opts, []), + Passwords = ?GET_OPT(user_passwords, Opts), case lists:keysearch(User, 1, Passwords) of {value, {User, Pw}} -> Pw; - false -> proplists:get_value(password, Opts, false) + false -> ?GET_OPT(password, Opts) end. -verify_sig(SessionId, User, Service, Alg, KeyBlob, SigWLen, Opts) -> - {ok, Key} = decode_public_key_v2(KeyBlob, Alg), - KeyCb = proplists:get_value(key_cb, Opts, ssh_file), +pre_verify_sig(User, KeyBlob, Opts) -> + try + Key = public_key:ssh_decode(KeyBlob, ssh2_pubkey), % or exception + {KeyCb,KeyCbOpts} = ?GET_OPT(key_cb, Opts), + UserOpts = ?GET_OPT(user_options, Opts), + KeyCb:is_auth_key(Key, User, [{key_cb_private,KeyCbOpts}|UserOpts]) + catch + _:_ -> + false + end. - case KeyCb:is_auth_key(Key, User, Opts) of - true -> - PlainText = build_sig_data(SessionId, User, - Service, KeyBlob, Alg), - <<?UINT32(AlgSigLen), AlgSig:AlgSigLen/binary>> = SigWLen, - <<?UINT32(AlgLen), _Alg:AlgLen/binary, - ?UINT32(SigLen), Sig:SigLen/binary>> = AlgSig, - ssh_transport:verify(PlainText, sha, Sig, Key); - false -> +verify_sig(SessionId, User, Service, AlgBin, KeyBlob, SigWLen, Opts) -> + try + Alg = binary_to_list(AlgBin), + {KeyCb,KeyCbOpts} = ?GET_OPT(key_cb, Opts), + UserOpts = ?GET_OPT(user_options, Opts), + Key = public_key:ssh_decode(KeyBlob, ssh2_pubkey), % or exception + true = KeyCb:is_auth_key(Key, User, [{key_cb_private,KeyCbOpts}|UserOpts]), + PlainText = build_sig_data(SessionId, User, Service, KeyBlob, Alg), + <<?UINT32(AlgSigLen), AlgSig:AlgSigLen/binary>> = SigWLen, + <<?UINT32(AlgLen), _Alg:AlgLen/binary, + ?UINT32(SigLen), Sig:SigLen/binary>> = AlgSig, + ssh_transport:verify(PlainText, ssh_transport:sha(Alg), Sig, Key) + catch + _:_ -> false end. @@ -468,11 +550,14 @@ decode_keyboard_interactive_prompts(_NumPrompts, Data) -> keyboard_interact_get_responses(IoCb, Opts, Name, Instr, PromptInfos) -> NumPrompts = length(PromptInfos), - keyboard_interact_get_responses(proplists:get_value(user_interaction, Opts, true), - proplists:get_value(keyboard_interact_fun, Opts), - proplists:get_value(password, Opts, undefined), IoCb, Name, + keyboard_interact_get_responses(?GET_OPT(user_interaction, Opts), + ?GET_OPT(keyboard_interact_fun, Opts), + ?GET_OPT(password, Opts), IoCb, Name, Instr, PromptInfos, Opts, NumPrompts). + +keyboard_interact_get_responses(_, _, not_ok, _, _, _, _, _, _) -> + not_ok; keyboard_interact_get_responses(_, undefined, Password, _, _, _, _, _, 1) when Password =/= undefined -> [Password]; %% Password auth implemented with keyboard-interaction and passwd is known @@ -486,17 +571,18 @@ keyboard_interact_get_responses(true, Fun, _Pwd, _IoCb, Name, Instr, PromptInfos keyboard_interact_fun(Fun, Name, Instr, PromptInfos, NumPrompts). keyboard_interact(IoCb, Name, Instr, Prompts, Opts) -> - if Name /= "" -> IoCb:format("~s~n", [Name]); - true -> ok - end, - if Instr /= "" -> IoCb:format("~s~n", [Instr]); - true -> ok - end, + write_if_nonempty(IoCb, Name), + write_if_nonempty(IoCb, Instr), lists:map(fun({Prompt, true}) -> IoCb:read_line(Prompt, Opts); ({Prompt, false}) -> IoCb:read_password(Prompt, Opts) end, Prompts). +write_if_nonempty(_, "") -> ok; +write_if_nonempty(_, <<>>) -> ok; +write_if_nonempty(IoCb, Text) -> IoCb:format("~s~n",[Text]). + + keyboard_interact_fun(KbdInteractFun, Name, Instr, PromptInfos, NumPrompts) -> Prompts = lists:map(fun({Prompt, _Echo}) -> Prompt end, PromptInfos), @@ -512,18 +598,7 @@ keyboard_interact_fun(KbdInteractFun, Name, Instr, PromptInfos, NumPrompts) -> language = "en"}}) end. -decode_public_key_v2(Bin, _Type) -> - try - public_key:ssh_decode(Bin, ssh2_pubkey) - of - Key -> {ok, Key} - catch - _:_ -> {error, bad_format} - end. -encode_public_key(_Alg, Key) -> - try - public_key:ssh_encode(Key, ssh2_pubkey) - catch - _:_ -> not_ok - end. +key_alg('rsa-sha2-256') -> 'ssh-rsa'; +key_alg('rsa-sha2-512') -> 'ssh-rsa'; +key_alg(Alg) -> Alg. |