diff options
Diffstat (limited to 'lib/ssh/src/ssh_auth.erl')
| -rw-r--r-- | lib/ssh/src/ssh_auth.erl | 355 |
1 files changed, 226 insertions, 129 deletions
diff --git a/lib/ssh/src/ssh_auth.erl b/lib/ssh/src/ssh_auth.erl index 49eec8072f..ac35b70209 100644 --- a/lib/ssh/src/ssh_auth.erl +++ b/lib/ssh/src/ssh_auth.erl @@ -31,24 +31,123 @@ -export([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 %%-------------------------------------------------------------------- +%%%---------------------------------------------------------------- +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} = Ssh0]) -> + {Password,Ssh} = + case proplists:get_value(password, Opts) of + undefined when IoCb == ssh_no_io -> + {not_ok, Ssh0}; + undefined -> + {IoCb:read_password("ssh password: ",Ssh0), Ssh0}; + PW -> + %% If "password" option is given it should not be tried again + {PW, Ssh0#ssh{opts = lists:keyreplace(password,1,Opts,{password,not_ok})}} + end, + case Password of + not_ok -> + {not_ok, Ssh}; + _ -> + ssh_transport:ssh_packet( + #ssh_msg_userauth_request{user = User, + service = Service, + method = "password", + data = + <<?BOOLEAN(?FALSE), + ?STRING(unicode:characters_to_binary(Password))>>}, + Ssh) + end. + +%% See RFC 4256 for info on keyboard-interactive +keyboard_interactive_msg([#ssh{user = User, + opts = Opts, + service = Service} = Ssh]) -> + case proplists:get_value(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. + publickey_msg([Alg, #ssh{user = User, session_id = SessionId, service = Service, opts = Opts} = Ssh]) -> - Hash = sha, %% Maybe option?! + Hash = ssh_transport:sha(Alg), 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; + {not_ok, Ssh}; PubKeyBlob -> SigData = build_sig_data(SessionId, User, Service, PubKeyBlob, StrAlgo), @@ -65,52 +164,15 @@ publickey_msg([Alg, #ssh{user = User, Ssh) end; _Error -> - not_ok - end. - -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, - case Password of - not_ok -> - not_ok; - _ -> - ssh_transport:ssh_packet( - #ssh_msg_userauth_request{user = User, - service = Service, - method = "password", - data = - <<?BOOLEAN(?FALSE), - ?STRING(unicode:characters_to_binary(Password))>>}, - Ssh) + {not_ok, 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, - service = Service} = Ssh]) -> - ssh_transport:ssh_packet( - #ssh_msg_userauth_request{user = User, - service = Service, - method = "keyboard-interactive", - data = << ?STRING(<<"">>), - ?STRING(<<>>) >> }, - Ssh). - +%%%---------------------------------------------------------------- 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} -> @@ -140,34 +202,9 @@ init_userauth_request_msg(#ssh{opts = Opts} = Ssh) -> 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) - 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 +260,54 @@ 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, binary_to_list(BAlg), + 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", + binary_to_list(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, @@ -319,31 +378,50 @@ 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 = proplists:get_value(tstflg, Opts) == one_empty, 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 +431,11 @@ 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( @@ -369,11 +452,6 @@ method_preference(Algs) -> [{"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). @@ -434,19 +512,34 @@ get_password_option(Opts, User) -> false -> proplists:get_value(password, Opts, false) 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, Alg, KeyBlob, Opts) -> + try + {ok, Key} = decode_public_key_v2(KeyBlob, Alg), + KeyCb = proplists:get_value(key_cb, Opts, ssh_file), + KeyCb:is_auth_key(Key, User, Opts) + 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, Alg, KeyBlob, SigWLen, Opts) -> + try + {ok, Key} = decode_public_key_v2(KeyBlob, Alg), + KeyCb = proplists:get_value(key_cb, Opts, ssh_file), + + 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, ssh_transport:sha(list_to_atom(Alg)), Sig, Key); + false -> + false + end + catch + _:_ -> false end. @@ -473,6 +566,9 @@ keyboard_interact_get_responses(IoCb, Opts, Name, Instr, PromptInfos) -> proplists:get_value(password, Opts, undefined), 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 +582,18 @@ 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), |