%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 2004-2012. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in %% compliance with the License. You should have received a copy of the %% Erlang Public License along with this software. If not, it can be %% retrieved online at http://www.erlang.org/. %% %% Software distributed under the License is distributed on an "AS IS" %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See %% the License for the specific language governing rights and limitations %% under the License. %% %% %CopyrightEnd% %% %% %%% Description: SSH transport protocol -module(ssh_transport). -include_lib("public_key/include/public_key.hrl"). -include_lib("kernel/include/inet.hrl"). -include("ssh_transport.hrl"). -include("ssh.hrl"). -export([connect/5, accept/4]). -export([versions/2, hello_version_msg/1]). -export([next_seqnum/1, decrypt_first_block/2, decrypt_blocks/3, is_valid_mac/3, transport_messages/1, kexdh_messages/0, kex_dh_gex_messages/0, handle_hello_version/1, key_exchange_init_msg/1, key_init/3, new_keys_message/1, handle_kexinit_msg/3, handle_kexdh_init/2, handle_kex_dh_gex_group/2, handle_kex_dh_gex_reply/2, handle_new_keys/2, handle_kex_dh_gex_request/2, handle_kexdh_reply/2, unpack/3, decompress/2, ssh_packet/2, pack/2, msg_data/1]). versions(client, Options)-> Vsn = proplists:get_value(vsn, Options, ?DEFAULT_CLIENT_VERSION), Version = format_version(Vsn), {Vsn, Version}; versions(server, Options) -> Vsn = proplists:get_value(vsn, Options, ?DEFAULT_SERVER_VERSION), Version = format_version(Vsn), {Vsn, Version}. hello_version_msg(Data) -> [Data,"\r\n"]. next_seqnum(SeqNum) -> (SeqNum + 1) band 16#ffffffff. decrypt_first_block(Bin, #ssh{decrypt_block_size = BlockSize} = Ssh0) -> <> = Bin, {Ssh, <> = DecData} = decrypt(Ssh0, EncBlock), {Ssh, PacketLen, DecData, EncData}. decrypt_blocks(Bin, Length, Ssh0) -> <> = Bin, {Ssh, DecData} = decrypt(Ssh0, EncBlocks), {Ssh, DecData, EncData}. is_valid_mac(_, _ , #ssh{recv_mac_size = 0}) -> true; is_valid_mac(Mac, Data, #ssh{recv_mac = Algorithm, recv_mac_key = Key, recv_sequence = SeqNum}) -> Mac == mac(Algorithm, Key, SeqNum, Data). transport_messages(_) -> [{ssh_msg_disconnect, ?SSH_MSG_DISCONNECT, [uint32, string, string]}, {ssh_msg_ignore, ?SSH_MSG_IGNORE, [string]}, {ssh_msg_unimplemented, ?SSH_MSG_UNIMPLEMENTED, [uint32]}, {ssh_msg_debug, ?SSH_MSG_DEBUG, [boolean, string, string]}, {ssh_msg_service_request, ?SSH_MSG_SERVICE_REQUEST, [string]}, {ssh_msg_service_accept, ?SSH_MSG_SERVICE_ACCEPT, [string]}, {ssh_msg_kexinit, ?SSH_MSG_KEXINIT, [cookie, name_list, name_list, name_list, name_list, name_list, name_list, name_list, name_list, name_list, name_list, boolean, uint32]}, {ssh_msg_newkeys, ?SSH_MSG_NEWKEYS, []} ]. kexdh_messages() -> [{ssh_msg_kexdh_init, ?SSH_MSG_KEXDH_INIT, [mpint]}, {ssh_msg_kexdh_reply, ?SSH_MSG_KEXDH_REPLY, [binary, mpint, binary]} ]. kex_dh_gex_messages() -> [{ssh_msg_kex_dh_gex_request, ?SSH_MSG_KEX_DH_GEX_REQUEST, [uint32, uint32, uint32]}, {ssh_msg_kex_dh_gex_request_old, ?SSH_MSG_KEX_DH_GEX_REQUEST_OLD, [uint32]}, {ssh_msg_kex_dh_gex_group, ?SSH_MSG_KEX_DH_GEX_GROUP, [mpint, mpint]}, {ssh_msg_kex_dh_gex_init, ?SSH_MSG_KEX_DH_GEX_INIT, [mpint]}, {ssh_msg_kex_dh_gex_reply, ?SSH_MSG_KEX_DH_GEX_REPLY, [binary, mpint, binary]} ]. yes_no(Ssh, Prompt) -> (Ssh#ssh.io_cb):yes_no(Prompt). connect(ConnectionSup, Address, Port, SocketOpts, Opts) -> Timeout = proplists:get_value(connect_timeout, Opts, infinity), {_, Callback, _} = proplists:get_value(transport, Opts, {tcp, gen_tcp, tcp_closed}), case do_connect(Callback, Address, Port, SocketOpts, Timeout) of {ok, Socket} -> {ok, Pid} = ssh_connection_controler:start_handler_child(ConnectionSup, [client, Socket, [{address, Address}, {port, Port} | Opts]]), Callback:controlling_process(Socket, Pid), ssh_connection_handler:send_event(Pid, socket_control), {ok, Pid}; {error, Reason} -> {error, Reason} end. do_connect(Callback, Address, Port, SocketOpts, Timeout) -> Opts = [{active, false} | SocketOpts], case Callback:connect(Address, Port, Opts, Timeout) of {error, nxdomain} -> Callback:connect(Address, Port, lists:delete(inet6, Opts), Timeout); {error, eafnosupport} -> Callback:connect(Address, Port, lists:delete(inet6, Opts), Timeout); {error, enetunreach} -> Callback:connect(Address, Port, lists:delete(inet6, Opts), Timeout); Other -> Other end. accept(Address, Port, Socket, Options) -> {_, Callback, _} = proplists:get_value(transport, Options, {tcp, gen_tcp, tcp_closed}), ConnectionSup = ssh_system_sup:connection_supervisor( ssh_system_sup:system_supervisor(Address, Port)), {ok, Pid} = ssh_connection_controler:start_handler_child(ConnectionSup, [server, Socket, [{address, Address}, {port, Port} | Options]]), Callback:controlling_process(Socket, Pid), ssh_connection_handler:send_event(Pid, socket_control), {ok, Pid}. format_version({Major,Minor}) -> "SSH-" ++ integer_to_list(Major) ++ "." ++ integer_to_list(Minor) ++ "-Erlang". handle_hello_version(Version) -> StrVersion = trim_tail(Version), case string:tokens(Version, "-") of [_, "2.0" | _] -> {{2,0}, StrVersion}; [_, "1.99" | _] -> {{2,0}, StrVersion}; [_, "1.3" | _] -> {{1,3}, StrVersion}; [_, "1.5" | _] -> {{1,5}, StrVersion} end. key_exchange_init_msg(Ssh0) -> Msg = kex_init(Ssh0), {SshPacket, Ssh} = ssh_packet(Msg, Ssh0), {Msg, SshPacket, Ssh}. kex_init(#ssh{role = Role, opts = Opts}) -> Random = ssh_bits:random(16), Compression = case proplists:get_value(compression, Opts, none) of zlib -> ["zlib", "none"]; none -> ["none", "zlib"] end, kexinit_messsage(Role, Random, Compression). key_init(client, Ssh, Value) -> Ssh#ssh{c_keyinit = Value}; key_init(server, Ssh, Value) -> Ssh#ssh{s_keyinit = Value}. kexinit_messsage(client, Random, Compression) -> #ssh_msg_kexinit{ cookie = Random, kex_algorithms = ["diffie-hellman-group1-sha1"], server_host_key_algorithms = ["ssh-rsa", "ssh-dss"], encryption_algorithms_client_to_server = ["aes128-cbc","3des-cbc"], encryption_algorithms_server_to_client = ["aes128-cbc","3des-cbc"], mac_algorithms_client_to_server = ["hmac-sha1"], mac_algorithms_server_to_client = ["hmac-sha1"], compression_algorithms_client_to_server = Compression, compression_algorithms_server_to_client = Compression, languages_client_to_server = [], languages_server_to_client = [] }; kexinit_messsage(server, Random, Compression) -> #ssh_msg_kexinit{ cookie = Random, kex_algorithms = ["diffie-hellman-group1-sha1"], server_host_key_algorithms = ["ssh-dss"], encryption_algorithms_client_to_server = ["aes128-cbc","3des-cbc"], encryption_algorithms_server_to_client = ["aes128-cbc","3des-cbc"], mac_algorithms_client_to_server = ["hmac-sha1"], mac_algorithms_server_to_client = ["hmac-sha1"], compression_algorithms_client_to_server = Compression, compression_algorithms_server_to_client = Compression, languages_client_to_server = [], languages_server_to_client = [] }. new_keys_message(Ssh0) -> {SshPacket, Ssh} = ssh_packet(#ssh_msg_newkeys{}, Ssh0), {ok, SshPacket, Ssh}. handle_kexinit_msg(#ssh_msg_kexinit{} = CounterPart, #ssh_msg_kexinit{} = Own, #ssh{role = client} = Ssh0) -> {ok, Algoritms} = select_algorithm(client, Own, CounterPart), case verify_algorithm(Algoritms) of true -> install_messages(Algoritms#alg.kex), key_exchange_first_msg(Algoritms#alg.kex, Ssh0#ssh{algorithms = Algoritms}); _ -> %% TODO: Correct code? throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR, description = "Selection of key exchange" " algorithm failed", language = "en"}) end; handle_kexinit_msg(#ssh_msg_kexinit{} = CounterPart, #ssh_msg_kexinit{} = Own, #ssh{role = server} = Ssh) -> {ok, Algoritms} = select_algorithm(server, CounterPart, Own), install_messages(Algoritms#alg.kex), {ok, Ssh#ssh{algorithms = Algoritms}}. %% TODO: diffie-hellman-group14-sha1 should also be supported. %% Maybe check more things ... verify_algorithm(#alg{kex = 'diffie-hellman-group1-sha1'}) -> true; verify_algorithm(#alg{kex = 'diffie-hellman-group-exchange-sha1'}) -> true; verify_algorithm(_) -> false. install_messages('diffie-hellman-group1-sha1') -> ssh_bits:install_messages(kexdh_messages()); install_messages('diffie-hellman-group-exchange-sha1') -> ssh_bits:install_messages(kex_dh_gex_messages()). key_exchange_first_msg('diffie-hellman-group1-sha1', Ssh0) -> {G, P} = dh_group1(), {Private, Public} = dh_gen_key(G, P, 1024), {SshPacket, Ssh1} = ssh_packet(#ssh_msg_kexdh_init{e = Public}, Ssh0), {ok, SshPacket, Ssh1#ssh{keyex_key = {{Private, Public}, {G, P}}}}; key_exchange_first_msg('diffie-hellman-group-exchange-sha1', Ssh0) -> Min = ?DEFAULT_DH_GROUP_MIN, NBits = ?DEFAULT_DH_GROUP_NBITS, Max = ?DEFAULT_DH_GROUP_MAX, {SshPacket, Ssh1} = ssh_packet(#ssh_msg_kex_dh_gex_request{min = Min, n = NBits, max = Max}, Ssh0), {ok, SshPacket, Ssh1#ssh{keyex_info = {Min, Max, NBits}}}. handle_kexdh_init(#ssh_msg_kexdh_init{e = E}, Ssh0) -> {G, P} = dh_group1(), {Private, Public} = dh_gen_key(G, P, 1024), K = ssh_math:ipow(E, Private, P), {Key, K_S} = get_host_key(Ssh0), H = kex_h(Ssh0, K_S, E, Public, K), H_SIG = sign_host_key(Ssh0, Key, H), {SshPacket, Ssh1} = ssh_packet(#ssh_msg_kexdh_reply{public_host_key = K_S, f = Public, h_sig = H_SIG }, Ssh0), {ok, SshPacket, Ssh1#ssh{keyex_key = {{Private, Public}, {G, P}}, shared_secret = K, exchanged_hash = H, session_id = sid(Ssh1, H)}}. handle_kex_dh_gex_group(#ssh_msg_kex_dh_gex_group{p = P, g = G}, Ssh0) -> {Private, Public} = dh_gen_key(G,P,1024), {SshPacket, Ssh1} = ssh_packet(#ssh_msg_kex_dh_gex_init{e = Public}, Ssh0), {ok, SshPacket, Ssh1#ssh{keyex_key = {{Private, Public}, {G, P}}}}. handle_new_keys(#ssh_msg_newkeys{}, Ssh0) -> try install_alg(Ssh0) of #ssh{} = Ssh -> {ok, Ssh} catch error:_Error -> %% TODO: Throw earlier .... throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR, description = "Install alg failed", language = "en"}) end. %% %% Select algorithms handle_kexdh_reply(#ssh_msg_kexdh_reply{public_host_key = HostKey, f = F, h_sig = H_SIG}, #ssh{keyex_key = {{Private, Public}, {_G, P}}} = Ssh0) -> K = ssh_math:ipow(F, Private, P), H = kex_h(Ssh0, HostKey, Public, F, K), case verify_host_key(Ssh0, HostKey, H, H_SIG) of ok -> {SshPacket, Ssh} = ssh_packet(#ssh_msg_newkeys{}, Ssh0), {ok, SshPacket, Ssh#ssh{shared_secret = K, exchanged_hash = H, session_id = sid(Ssh, H)}}; _Error -> Disconnect = #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed", language = "en"}, throw(Disconnect) end. handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request{min = _Min, n = _NBits, max = _Max}, Ssh0) -> {G,P} = dh_group1(), %% TODO real imp this seems to be a hack?! {Private, Public} = dh_gen_key(G, P, 1024), {SshPacket, Ssh} = ssh_packet(#ssh_msg_kex_dh_gex_group{p = P, g = G}, Ssh0), {ok, SshPacket, Ssh#ssh{keyex_key = {{Private, Public}, {G, P}}}}. handle_kex_dh_gex_reply(#ssh_msg_kex_dh_gex_reply{public_host_key = HostKey, f = F, h_sig = H_SIG}, #ssh{keyex_key = {{Private, Public}, {G, P}}, keyex_info = {Min, Max, NBits}} = Ssh0) -> K = ssh_math:ipow(F, Private, P), H = kex_h(Ssh0, HostKey, Min, NBits, Max, P, G, Public, F, K), case verify_host_key(Ssh0, HostKey, H, H_SIG) of ok -> {SshPacket, Ssh} = ssh_packet(#ssh_msg_newkeys{}, Ssh0), {ok, SshPacket, Ssh#ssh{shared_secret = K, exchanged_hash = H, session_id = sid(Ssh, H)}}; _Error -> Disconnect = #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed", language = "en"}, throw(Disconnect) end. %% select session id sid(#ssh{session_id = undefined}, H) -> H; sid(#ssh{session_id = Id}, _) -> Id. %% %% The host key should be read from storage %% get_host_key(SSH) -> #ssh{key_cb = Mod, opts = Opts, algorithms = ALG} = SSH, Scope = proplists:get_value(key_scope, Opts, system), case ALG#alg.hkey of 'ssh-rsa' -> case Mod:private_host_rsa_key(Scope, Opts) of {ok, #'RSAPrivateKey'{modulus = N, publicExponent = E} = Key} -> {Key, ssh_bits:encode(["ssh-rsa",E,N],[string,mpint,mpint])}; Error -> exit(Error) end; 'ssh-dss' -> case Mod:private_host_dsa_key(Scope, Opts) of {ok, #'DSAPrivateKey'{y = Y, p = P, q = Q, g = G} = Key} -> {Key, ssh_bits:encode(["ssh-dss",P,Q,G,Y], [string,mpint,mpint,mpint,mpint])}; Error -> exit(Error) end; _ -> exit({error, bad_key_type}) end. sign_host_key(_Ssh, #'RSAPrivateKey'{} = Private, H) -> Hash = sha, %% Option ?! Signature = public_key:sign(H, Hash, Private), ssh_bits:encode(["ssh-rsa", Signature],[string, binary]); sign_host_key(_Ssh, #'DSAPrivateKey'{} = Private, H) -> Hash = sha, %% Option ?! DerSignature = public_key:sign(H, Hash, Private), #'Dss-Sig-Value'{r = R, s = S} = public_key:der_decode('Dss-Sig-Value', DerSignature), RawSignature = <>, ssh_bits:encode(["ssh-dss", RawSignature],[string, binary]). verify_host_key(SSH, K_S, H, H_SIG) -> ALG = SSH#ssh.algorithms, case ALG#alg.hkey of 'ssh-rsa' -> verify_host_key_rsa(SSH, K_S, H, H_SIG); 'ssh-dss' -> verify_host_key_dss(SSH, K_S, H, H_SIG); _ -> {error, bad_host_key_algorithm} end. verify_host_key_rsa(SSH, K_S, H, H_SIG) -> case ssh_bits:decode(K_S,[string,mpint,mpint]) of ["ssh-rsa", E, N] -> ["ssh-rsa",SIG] = ssh_bits:decode(H_SIG,[string,binary]), Public = #'RSAPublicKey'{publicExponent = E, modulus = N}, case public_key:verify(H, sha, SIG, Public) of false -> {error, bad_signature}; true -> known_host_key(SSH, Public, "ssh-rsa") end; _ -> {error, bad_format} end. verify_host_key_dss(SSH, K_S, H, H_SIG) -> case ssh_bits:decode(K_S,[string,mpint,mpint,mpint,mpint]) of ["ssh-dss",P,Q,G,Y] -> ["ssh-dss",SIG] = ssh_bits:decode(H_SIG,[string,binary]), Public = {Y, #'Dss-Parms'{p = P, q = Q, g = G}}, <> = SIG, Signature = public_key:der_encode('Dss-Sig-Value', #'Dss-Sig-Value'{r = R, s = S}), case public_key:verify(H, sha, Signature, Public) of false -> {error, bad_signature}; true -> known_host_key(SSH, Public, "ssh-dss") end; _ -> {error, bad_host_key_format} end. accepted_host(Ssh, PeerName, Opts) -> case proplists:get_value(silently_accept_hosts, Opts, false) of true -> yes; false -> yes_no(Ssh, "New host " ++ PeerName ++ " accept") end. known_host_key(#ssh{opts = Opts, key_cb = Mod, peer = Peer} = Ssh, Public, Alg) -> PeerName = peer_name(Peer), case Mod:lookup_host_key(PeerName, Alg, Opts) of {ok, Public} -> ok; {ok, BadPublic} -> error_logger:format("known_host_key: Public ~p BadPublic ~p\n", [Public, BadPublic]), {error, bad_public_key}; {error, not_found} -> case accepted_host(Ssh, PeerName, Opts) of yes -> Mod:add_host_key(PeerName, Public, Opts); no -> {error, rejected} end end. %% Each of the algorithm strings MUST be a comma-separated list of %% algorithm names (see ''Algorithm Naming'' in [SSH-ARCH]). Each %% supported (allowed) algorithm MUST be listed in order of preference. %% %% The first algorithm in each list MUST be the preferred (guessed) %% algorithm. Each string MUST contain at least one algorithm name. select_algorithm(Role, Client, Server) -> {Encrypt, Decrypt} = select_encrypt_decrypt(Role, Client, Server), {SendMac, RecvMac} = select_send_recv_mac(Role, Client, Server), {Compression, Decompression} = select_compression_decompression(Role, Client, Server), C_Lng = select(Client#ssh_msg_kexinit.languages_client_to_server, Server#ssh_msg_kexinit.languages_client_to_server), S_Lng = select(Client#ssh_msg_kexinit.languages_server_to_client, Server#ssh_msg_kexinit.languages_server_to_client), HKey = select_all(Client#ssh_msg_kexinit.server_host_key_algorithms, Server#ssh_msg_kexinit.server_host_key_algorithms), HK = case HKey of [] -> undefined; [HK0|_] -> HK0 end, %% Fixme verify Kex against HKey list and algorithms Kex = select(Client#ssh_msg_kexinit.kex_algorithms, Server#ssh_msg_kexinit.kex_algorithms), Alg = #alg{kex = Kex, hkey = HK, encrypt = Encrypt, decrypt = Decrypt, send_mac = SendMac, recv_mac = RecvMac, compress = Compression, decompress = Decompression, c_lng = C_Lng, s_lng = S_Lng}, {ok, Alg}. select_encrypt_decrypt(client, Client, Server) -> Encrypt = select(Client#ssh_msg_kexinit.encryption_algorithms_client_to_server, Server#ssh_msg_kexinit.encryption_algorithms_client_to_server), Decrypt = select(Client#ssh_msg_kexinit.encryption_algorithms_server_to_client, Server#ssh_msg_kexinit.encryption_algorithms_server_to_client), {Encrypt, Decrypt}; select_encrypt_decrypt(server, Client, Server) -> Decrypt = select(Client#ssh_msg_kexinit.encryption_algorithms_client_to_server, Server#ssh_msg_kexinit.encryption_algorithms_client_to_server), Encrypt = select(Client#ssh_msg_kexinit.encryption_algorithms_server_to_client, Server#ssh_msg_kexinit.encryption_algorithms_server_to_client), {Encrypt, Decrypt}. select_send_recv_mac(client, Client, Server) -> SendMac = select(Client#ssh_msg_kexinit.mac_algorithms_client_to_server, Server#ssh_msg_kexinit.mac_algorithms_client_to_server), RecvMac = select(Client#ssh_msg_kexinit.mac_algorithms_server_to_client, Server#ssh_msg_kexinit.mac_algorithms_server_to_client), {SendMac, RecvMac}; select_send_recv_mac(server, Client, Server) -> RecvMac = select(Client#ssh_msg_kexinit.mac_algorithms_client_to_server, Server#ssh_msg_kexinit.mac_algorithms_client_to_server), SendMac = select(Client#ssh_msg_kexinit.mac_algorithms_server_to_client, Server#ssh_msg_kexinit.mac_algorithms_server_to_client), {SendMac, RecvMac}. select_compression_decompression(client, Client, Server) -> Compression = select(Client#ssh_msg_kexinit.compression_algorithms_client_to_server, Server#ssh_msg_kexinit.compression_algorithms_client_to_server), Decomprssion = select(Client#ssh_msg_kexinit.compression_algorithms_server_to_client, Server#ssh_msg_kexinit.compression_algorithms_server_to_client), {Compression, Decomprssion}; select_compression_decompression(server, Client, Server) -> Decomprssion = select(Client#ssh_msg_kexinit.compression_algorithms_client_to_server, Server#ssh_msg_kexinit.compression_algorithms_client_to_server), Compression = select(Client#ssh_msg_kexinit.compression_algorithms_server_to_client, Server#ssh_msg_kexinit.compression_algorithms_server_to_client), {Compression, Decomprssion}. install_alg(SSH) -> SSH1 = alg_final(SSH), SSH2 = alg_setup(SSH1), alg_init(SSH2). alg_setup(SSH) -> ALG = SSH#ssh.algorithms, SSH#ssh{kex = ALG#alg.kex, hkey = ALG#alg.hkey, encrypt = ALG#alg.encrypt, decrypt = ALG#alg.decrypt, send_mac = ALG#alg.send_mac, send_mac_size = mac_digest_size(ALG#alg.send_mac), recv_mac = ALG#alg.recv_mac, recv_mac_size = mac_digest_size(ALG#alg.recv_mac), compress = ALG#alg.compress, decompress = ALG#alg.decompress, c_lng = ALG#alg.c_lng, s_lng = ALG#alg.s_lng, algorithms = undefined }. alg_init(SSH0) -> {ok,SSH1} = send_mac_init(SSH0), {ok,SSH2} = recv_mac_init(SSH1), {ok,SSH3} = encrypt_init(SSH2), {ok,SSH4} = decrypt_init(SSH3), {ok,SSH5} = compress_init(SSH4), {ok,SSH6} = decompress_init(SSH5), SSH6. alg_final(SSH0) -> {ok,SSH1} = send_mac_final(SSH0), {ok,SSH2} = recv_mac_final(SSH1), {ok,SSH3} = encrypt_final(SSH2), {ok,SSH4} = decrypt_final(SSH3), {ok,SSH5} = compress_final(SSH4), {ok,SSH6} = decompress_final(SSH5), SSH6. select_all(CL, SL) -> A = CL -- SL, %% algortihms only used by client %% algorithms used by client and server (client pref) lists:map(fun(ALG) -> list_to_atom(ALG) end, (CL -- A)). select([], []) -> none; select(CL, SL) -> C = case select_all(CL,SL) of [] -> undefined; [ALG|_] -> ALG end, C. ssh_packet(#ssh_msg_kexinit{} = Msg, Ssh0) -> BinMsg = ssh_bits:encode(Msg), Ssh = key_init(Ssh0#ssh.role, Ssh0, BinMsg), pack(BinMsg, Ssh); ssh_packet(Msg, Ssh) -> BinMsg = ssh_bits:encode(Msg), pack(BinMsg, Ssh). pack(Data0, #ssh{encrypt_block_size = BlockSize, send_sequence = SeqNum, send_mac = MacAlg, send_mac_key = MacKey} = Ssh0) when is_binary(Data0) -> {Ssh1, Data} = compress(Ssh0, Data0), PL = (BlockSize - ((4 + 1 + size(Data)) rem BlockSize)) rem BlockSize, PaddingLen = if PL < 4 -> PL + BlockSize; true -> PL end, Padding = ssh_bits:random(PaddingLen), PacketLen = 1 + PaddingLen + size(Data), PacketData = <>, {Ssh2, EncPacket} = encrypt(Ssh1, PacketData), MAC = mac(MacAlg, MacKey, SeqNum, PacketData), Packet = [EncPacket, MAC], Ssh = Ssh2#ssh{send_sequence = (SeqNum+1) band 16#ffffffff}, {Packet, Ssh}. unpack(EncodedSoFar, ReminingLenght, #ssh{recv_mac_size = MacSize} = Ssh0) -> SshLength = ReminingLenght - MacSize, {NoMac, Mac, Rest} = case MacSize of 0 -> <> = EncodedSoFar, {NoMac0, <<>>, Rest0}; _ -> <> = EncodedSoFar, {NoMac0, Mac0, Rest0} end, {Ssh1, DecData, <<>>} = case SshLength of 0 -> {Ssh0, <<>>, <<>>}; _ -> decrypt_blocks(NoMac, SshLength, Ssh0) end, {Ssh1, DecData, Rest, Mac}. msg_data(PacketData) -> <> = PacketData, DataLen = Len - PaddingLen - 1, <<_:32, _:8, Data:DataLen/binary, _:PaddingLen/binary>> = PacketData, Data. %% public key algorithms %% %% ssh-dss REQUIRED sign Raw DSS Key %% ssh-rsa RECOMMENDED sign Raw RSA Key %% x509v3-sign-rsa OPTIONAL sign X.509 certificates (RSA key) %% x509v3-sign-dss OPTIONAL sign X.509 certificates (DSS key) %% spki-sign-rsa OPTIONAL sign SPKI certificates (RSA key) %% spki-sign-dss OPTIONAL sign SPKI certificates (DSS key) %% pgp-sign-rsa OPTIONAL sign OpenPGP certificates (RSA key) %% pgp-sign-dss OPTIONAL sign OpenPGP certificates (DSS key) %% %% key exchange %% %% diffie-hellman-group1-sha1 REQUIRED %% %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% Encryption %% %% chiphers %% %% 3des-cbc REQUIRED %% three-key 3DES in CBC mode %% blowfish-cbc OPTIONAL Blowfish in CBC mode %% twofish256-cbc OPTIONAL Twofish in CBC mode, %% with 256-bit key %% twofish-cbc OPTIONAL alias for "twofish256-cbc" (this %% is being retained for %% historical reasons) %% twofish192-cbc OPTIONAL Twofish with 192-bit key %% twofish128-cbc OPTIONAL Twofish with 128-bit key %% aes256-cbc OPTIONAL AES in CBC mode, %% with 256-bit key %% aes192-cbc OPTIONAL AES with 192-bit key %% aes128-cbc RECOMMENDED AES with 128-bit key %% serpent256-cbc OPTIONAL Serpent in CBC mode, with %% 256-bit key %% serpent192-cbc OPTIONAL Serpent with 192-bit key %% serpent128-cbc OPTIONAL Serpent with 128-bit key %% arcfour OPTIONAL the ARCFOUR stream cipher %% idea-cbc OPTIONAL IDEA in CBC mode %% cast128-cbc OPTIONAL CAST-128 in CBC mode %% none OPTIONAL no encryption; NOT RECOMMENDED %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% encrypt_init(#ssh{encrypt = none} = Ssh) -> {ok, Ssh}; encrypt_init(#ssh{encrypt = '3des-cbc', role = client} = Ssh) -> IV = hash(Ssh, "A", 64), <> = hash(Ssh, "C", 192), {ok, Ssh#ssh{encrypt_keys = {K1,K2,K3}, encrypt_block_size = 8, encrypt_ctx = IV}}; encrypt_init(#ssh{encrypt = '3des-cbc', role = server} = Ssh) -> IV = hash(Ssh, "B", 64), <> = hash(Ssh, "D", 192), {ok, Ssh#ssh{encrypt_keys = {K1,K2,K3}, encrypt_block_size = 8, encrypt_ctx = IV}}; encrypt_init(#ssh{encrypt = 'aes128-cbc', role = client} = Ssh) -> IV = hash(Ssh, "A", 128), <> = hash(Ssh, "C", 128), {ok, Ssh#ssh{encrypt_keys = K, encrypt_block_size = 16, encrypt_ctx = IV}}; encrypt_init(#ssh{encrypt = 'aes128-cbc', role = server} = Ssh) -> IV = hash(Ssh, "B", 128), <> = hash(Ssh, "D", 128), {ok, Ssh#ssh{encrypt_keys = K, encrypt_block_size = 16, encrypt_ctx = IV}}. encrypt_final(Ssh) -> {ok, Ssh#ssh{encrypt = none, encrypt_keys = undefined, encrypt_block_size = 8, encrypt_ctx = undefined }}. encrypt(#ssh{encrypt = none} = Ssh, Data) -> {Ssh, Data}; encrypt(#ssh{encrypt = '3des-cbc', encrypt_keys = {K1,K2,K3}, encrypt_ctx = IV0} = Ssh, Data) -> Enc = crypto:des3_cbc_encrypt(K1,K2,K3,IV0,Data), IV = crypto:des_cbc_ivec(Enc), {Ssh#ssh{encrypt_ctx = IV}, Enc}; encrypt(#ssh{encrypt = 'aes128-cbc', encrypt_keys = K, encrypt_ctx = IV0} = Ssh, Data) -> Enc = crypto:aes_cbc_128_encrypt(K,IV0,Data), IV = crypto:aes_cbc_ivec(Enc), {Ssh#ssh{encrypt_ctx = IV}, Enc}. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% Decryption %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% decrypt_init(#ssh{decrypt = none} = Ssh) -> {ok, Ssh}; decrypt_init(#ssh{decrypt = '3des-cbc', role = client} = Ssh) -> {IV, KD} = {hash(Ssh, "B", 64), hash(Ssh, "D", 192)}, <> = KD, {ok, Ssh#ssh{decrypt_keys = {K1,K2,K3}, decrypt_ctx = IV, decrypt_block_size = 8}}; decrypt_init(#ssh{decrypt = '3des-cbc', role = server} = Ssh) -> {IV, KD} = {hash(Ssh, "A", 64), hash(Ssh, "C", 192)}, <> = KD, {ok, Ssh#ssh{decrypt_keys = {K1, K2, K3}, decrypt_ctx = IV, decrypt_block_size = 8}}; decrypt_init(#ssh{decrypt = 'aes128-cbc', role = client} = Ssh) -> {IV, KD} = {hash(Ssh, "B", 128), hash(Ssh, "D", 128)}, <> = KD, {ok, Ssh#ssh{decrypt_keys = K, decrypt_ctx = IV, decrypt_block_size = 16}}; decrypt_init(#ssh{decrypt = 'aes128-cbc', role = server} = Ssh) -> {IV, KD} = {hash(Ssh, "A", 128), hash(Ssh, "C", 128)}, <> = KD, {ok, Ssh#ssh{decrypt_keys = K, decrypt_ctx = IV, decrypt_block_size = 16}}. decrypt_final(Ssh) -> {ok, Ssh#ssh {decrypt = none, decrypt_keys = undefined, decrypt_ctx = undefined, decrypt_block_size = 8}}. decrypt(#ssh{decrypt = none} = Ssh, Data) -> {Ssh, Data}; decrypt(#ssh{decrypt = '3des-cbc', decrypt_keys = Keys, decrypt_ctx = IV0} = Ssh, Data) -> {K1, K2, K3} = Keys, Dec = crypto:des3_cbc_decrypt(K1,K2,K3,IV0,Data), IV = crypto:des_cbc_ivec(Data), {Ssh#ssh{decrypt_ctx = IV}, Dec}; decrypt(#ssh{decrypt = 'aes128-cbc', decrypt_keys = Key, decrypt_ctx = IV0} = Ssh, Data) -> Dec = crypto:aes_cbc_128_decrypt(Key,IV0,Data), IV = crypto:aes_cbc_ivec(Data), {Ssh#ssh{decrypt_ctx = IV}, Dec}. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% Compression %% %% none REQUIRED no compression %% zlib OPTIONAL ZLIB (LZ77) compression %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% compress_init(SSH) -> compress_init(SSH, 1). compress_init(#ssh{compress = none} = Ssh, _) -> {ok, Ssh}; compress_init(#ssh{compress = zlib} = Ssh, Level) -> Zlib = zlib:open(), ok = zlib:deflateInit(Zlib, Level), {ok, Ssh#ssh{compress_ctx = Zlib}}. compress_final(#ssh{compress = none} = Ssh) -> {ok, Ssh}; compress_final(#ssh{compress = zlib, compress_ctx = Context} = Ssh) -> zlib:close(Context), {ok, Ssh#ssh{compress = none, compress_ctx = undefined}}. compress(#ssh{compress = none} = Ssh, Data) -> {Ssh, Data}; compress(#ssh{compress = zlib, compress_ctx = Context} = Ssh, Data) -> Compressed = zlib:deflate(Context, Data, sync), {Ssh, list_to_binary(Compressed)}. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% Decompression %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% decompress_init(#ssh{decompress = none} = Ssh) -> {ok, Ssh}; decompress_init(#ssh{decompress = zlib} = Ssh) -> Zlib = zlib:open(), ok = zlib:inflateInit(Zlib), {ok, Ssh#ssh{decompress_ctx = Zlib}}. decompress_final(#ssh{decompress = none} = Ssh) -> {ok, Ssh}; decompress_final(#ssh{decompress = zlib, decompress_ctx = Context} = Ssh) -> zlib:close(Context), {ok, Ssh#ssh{decompress = none, decompress_ctx = undefined}}. decompress(#ssh{decompress = none} = Ssh, Data) -> {Ssh, Data}; decompress(#ssh{decompress = zlib, decompress_ctx = Context} = Ssh, Data) -> Decompressed = zlib:inflate(Context, Data), {Ssh, list_to_binary(Decompressed)}. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% MAC calculation %% %% hmac-sha1 REQUIRED HMAC-SHA1 (digest length = key %% length = 20) %% hmac-sha1-96 RECOMMENDED first 96 bits of HMAC-SHA1 (digest %% length = 12, key length = 20) %% hmac-md5 OPTIONAL HMAC-MD5 (digest length = key %% length = 16) %% hmac-md5-96 OPTIONAL first 96 bits of HMAC-MD5 (digest %% length = 12, key length = 16) %% none OPTIONAL no MAC; NOT RECOMMENDED %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% send_mac_init(SSH) -> case SSH#ssh.role of client -> KeySize =mac_key_size(SSH#ssh.send_mac), Key = hash(SSH, "E", KeySize), {ok, SSH#ssh { send_mac_key = Key }}; server -> KeySize = mac_key_size(SSH#ssh.send_mac), Key = hash(SSH, "F", KeySize), {ok, SSH#ssh { send_mac_key = Key }} end. send_mac_final(SSH) -> {ok, SSH#ssh { send_mac = none, send_mac_key = undefined }}. recv_mac_init(SSH) -> case SSH#ssh.role of client -> Key = hash(SSH, "F", mac_key_size(SSH#ssh.recv_mac)), {ok, SSH#ssh { recv_mac_key = Key }}; server -> Key = hash(SSH, "E", mac_key_size(SSH#ssh.recv_mac)), {ok, SSH#ssh { recv_mac_key = Key }} end. recv_mac_final(SSH) -> {ok, SSH#ssh { recv_mac = none, recv_mac_key = undefined }}. mac(none, _ , _, _) -> <<>>; mac('hmac-sha1', Key, SeqNum, Data) -> crypto:sha_mac(Key, [<>, Data]); mac('hmac-sha1-96', Key, SeqNum, Data) -> crypto:sha_mac_96(Key, [<>, Data]); mac('hmac-md5', Key, SeqNum, Data) -> crypto:md5_mac(Key, [<>, Data]); mac('hmac-md5-96', Key, SeqNum, Data) -> crypto:md5_mac_96(Key, [<>, Data]). %% return N hash bytes (HASH) hash(SSH, Char, Bits) -> HASH = case SSH#ssh.kex of 'diffie-hellman-group1-sha1' -> fun(Data) -> crypto:sha(Data) end; 'diffie-hellman-group-exchange-sha1' -> fun(Data) -> crypto:sha(Data) end; _ -> exit({bad_algorithm,SSH#ssh.kex}) end, hash(SSH, Char, Bits, HASH). hash(_SSH, _Char, 0, _HASH) -> <<>>; hash(SSH, Char, N, HASH) -> K = ssh_bits:mpint(SSH#ssh.shared_secret), H = SSH#ssh.exchanged_hash, SessionID = SSH#ssh.session_id, K1 = HASH([K, H, Char, SessionID]), Sz = N div 8, <> = hash(K, H, K1, N-128, HASH), Key. hash(_K, _H, Ki, N, _HASH) when N =< 0 -> Ki; hash(K, H, Ki, N, HASH) -> Kj = HASH([K, H, Ki]), hash(K, H, <>, N-128, HASH). kex_h(SSH, K_S, E, F, K) -> L = ssh_bits:encode([SSH#ssh.c_version, SSH#ssh.s_version, SSH#ssh.c_keyinit, SSH#ssh.s_keyinit, K_S, E,F,K], [string,string,binary,binary,binary, mpint,mpint,mpint]), crypto:sha(L). kex_h(SSH, K_S, Min, NBits, Max, Prime, Gen, E, F, K) -> L = if Min==-1; Max==-1 -> Ts = [string,string,binary,binary,binary, uint32, mpint,mpint,mpint,mpint,mpint], ssh_bits:encode([SSH#ssh.c_version,SSH#ssh.s_version, SSH#ssh.c_keyinit,SSH#ssh.s_keyinit, K_S, NBits, Prime, Gen, E,F,K], Ts); true -> Ts = [string,string,binary,binary,binary, uint32,uint32,uint32, mpint,mpint,mpint,mpint,mpint], ssh_bits:encode([SSH#ssh.c_version,SSH#ssh.s_version, SSH#ssh.c_keyinit,SSH#ssh.s_keyinit, K_S, Min, NBits, Max, Prime, Gen, E,F,K], Ts) end, crypto:sha(L). mac_key_size('hmac-sha1') -> 20*8; mac_key_size('hmac-sha1-96') -> 20*8; mac_key_size('hmac-md5') -> 16*8; mac_key_size('hmac-md5-96') -> 16*8; mac_key_size(none) -> 0. mac_digest_size('hmac-sha1') -> 20; mac_digest_size('hmac-sha1-96') -> 12; mac_digest_size('hmac-md5') -> 20; mac_digest_size('hmac-md5-96') -> 12; mac_digest_size(none) -> 0. peer_name({Host, _}) -> Host. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %% Diffie-Hellman utils %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% dh_group1() -> {2, 16#FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF}. dh_gen_key(G, P, _Bits) -> Private = ssh_bits:irandom(ssh_bits:isize(P)-1, 1, 1), Public = ssh_math:ipow(G, Private, P), {Private,Public}. trim_tail(Str) -> lists:reverse(trim_head(lists:reverse(Str))). trim_head([$\s|Cs]) -> trim_head(Cs); trim_head([$\t|Cs]) -> trim_head(Cs); trim_head([$\n|Cs]) -> trim_head(Cs); trim_head([$\r|Cs]) -> trim_head(Cs); trim_head(Cs) -> Cs.