%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 2004-2014. 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% %% %% %%% 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([versions/2, hello_version_msg/1]). -export([next_seqnum/1, decrypt_first_block/2, decrypt_blocks/3, supported_algorithms/0, supported_algorithms/1, default_algorithms/0, default_algorithms/1, is_valid_mac/3, 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_init/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, sign/3, verify/4]). %%%---------------------------------------------------------------------------- %%% %%% There is a difference between supported and default algorithms. The %%% SUPPORTED algorithms can be handled (maybe untested...). The DEFAULT ones %%% are announced in ssh_msg_kexinit and in ssh:default_algorithms/0 to the %%% user. %%% %%% A supported algorithm can be requested in the option 'preferred_algorithms', %%% but may give unexpected results because of being promoted to default. %%% %%% This makes it possible to add experimental algorithms (in supported_algorithms) %%% and test them without letting the default users know about them. %%% default_algorithms() -> [{K,default_algorithms(K)} || K <- algo_classes()]. algo_classes() -> [kex, public_key, cipher, mac, compression]. default_algorithms(compression) -> %% Do not announce 'zlib@openssh.com' because there seem to be problems supported_algorithms(compression, same(['zlib@openssh.com'])); default_algorithms(kex) -> supported_algorithms(kex, []); default_algorithms(Alg) -> supported_algorithms(Alg). supported_algorithms() -> [{K,supported_algorithms(K)} || K <- algo_classes()]. supported_algorithms(kex) -> select_crypto_supported( [{'diffie-hellman-group14-sha1', [{hashs,sha}]}, {'diffie-hellman-group1-sha1', [{hashs,sha}]}, {'diffie-hellman-group-exchange-sha256', [{hashs,sha256}]}, {'diffie-hellman-group-exchange-sha1', [{hashs,sha}]} ]); supported_algorithms(public_key) -> ssh_auth:default_public_key_algorithms(); supported_algorithms(cipher) -> same( select_crypto_supported( [{'aes128-ctr', [{ciphers,aes_ctr}]}, {'aes128-cbc', [{ciphers,aes_cbc128}]}, {'3des-cbc', [{ciphers,des3_cbc}]} ] )); supported_algorithms(mac) -> same( select_crypto_supported( [{'hmac-sha2-256', [{hashs,sha256}]}, {'hmac-sha1', [{hashs,sha}]} ] )); supported_algorithms(compression) -> same(['none','zlib','zlib@openssh.com']). supported_algorithms(Key, [{client2server,BL1},{server2client,BL2}]) -> [{client2server,As1},{server2client,As2}] = supported_algorithms(Key), [{client2server,As1--BL1},{server2client,As2--BL2}]; supported_algorithms(Key, BlackList) -> supported_algorithms(Key) -- BlackList. select_crypto_supported(L) -> Sup = crypto:supports(), [Name || {Name,CryptoRequires} <- L, crypto_supported(CryptoRequires, Sup)]. crypto_supported(Conditions, Supported) -> lists:all(fun({Tag,CryptoName}) -> lists:member(CryptoName, proplists:get_value(Tag,Supported,[])) end, Conditions). same(Algs) -> [{client2server,Algs}, {server2client,Algs}]. %%%---------------------------------------------------------------------------- versions(client, Options)-> Vsn = proplists:get_value(vsn, Options, ?DEFAULT_CLIENT_VERSION), {Vsn, format_version(Vsn, software_version(Options))}; versions(server, Options) -> Vsn = proplists:get_value(vsn, Options, ?DEFAULT_SERVER_VERSION), {Vsn, format_version(Vsn, software_version(Options))}. software_version(Options) -> case proplists:get_value(id_string, Options) of undefined -> "Erlang"++ssh_vsn(); {random,Nlo,Nup} -> random_id(Nlo,Nup); ID -> ID end. ssh_vsn() -> try {ok,L} = application:get_all_key(ssh), proplists:get_value(vsn,L,"") of "" -> ""; VSN when is_list(VSN) -> "/" ++ VSN; _ -> "" catch _:_ -> "" end. random_id(Nlo, Nup) -> [crypto:rand_uniform($a,$z+1) || _<- lists:duplicate(crypto:rand_uniform(Nlo,Nup+1),x) ]. 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). yes_no(Ssh, Prompt) -> (Ssh#ssh.io_cb):yes_no(Prompt, Ssh). format_version({Major,Minor}, SoftwareVersion) -> "SSH-" ++ integer_to_list(Major) ++ "." ++ integer_to_list(Minor) ++ "-" ++ SoftwareVersion. handle_hello_version(Version) -> try 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 catch error:_ -> {undefined, "unknown version"} 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, available_host_keys = HostKeyAlgs}) -> Random = ssh_bits:random(16), PrefAlgs = case proplists:get_value(preferred_algorithms,Opts) of undefined -> default_algorithms(); Algs0 -> Algs0 end, kexinit_message(Role, Random, PrefAlgs, HostKeyAlgs). key_init(client, Ssh, Value) -> Ssh#ssh{c_keyinit = Value}; key_init(server, Ssh, Value) -> Ssh#ssh{s_keyinit = Value}. kexinit_message(_Role, Random, Algs, HostKeyAlgs) -> #ssh_msg_kexinit{ cookie = Random, kex_algorithms = to_strings( get_algs(kex,Algs) ), server_host_key_algorithms = HostKeyAlgs, encryption_algorithms_client_to_server = c2s(cipher,Algs), encryption_algorithms_server_to_client = s2c(cipher,Algs), mac_algorithms_client_to_server = c2s(mac,Algs), mac_algorithms_server_to_client = s2c(mac,Algs), compression_algorithms_client_to_server = c2s(compression,Algs), compression_algorithms_server_to_client = s2c(compression,Algs), languages_client_to_server = [], languages_server_to_client = [] }. c2s(Key, Algs) -> x2y(client2server, Key, Algs). s2c(Key, Algs) -> x2y(server2client, Key, Algs). x2y(DirectionKey, Key, Algs) -> to_strings(proplists:get_value(DirectionKey, get_algs(Key,Algs))). get_algs(Key, Algs) -> proplists:get_value(Key, Algs, default_algorithms(Key)). to_strings(L) -> lists:map(fun erlang:atom_to_list/1, L). 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 -> key_exchange_first_msg(Algoritms#alg.kex, Ssh0#ssh{algorithms = Algoritms}); _ -> %% TODO: Correct code? throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Selection of key exchange" " algorithm failed", language = ""}) end; handle_kexinit_msg(#ssh_msg_kexinit{} = CounterPart, #ssh_msg_kexinit{} = Own, #ssh{role = server} = Ssh) -> {ok, Algoritms} = select_algorithm(server, CounterPart, Own), case verify_algorithm(Algoritms) of true -> {ok, Ssh#ssh{algorithms = Algoritms}}; _ -> throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Selection of key exchange" " algorithm failed", language = ""}) end. %% TODO: diffie-hellman-group14-sha1 should also be supported. %% Maybe check more things ... verify_algorithm(#alg{kex = undefined}) -> false; verify_algorithm(#alg{hkey = undefined}) -> false; verify_algorithm(#alg{send_mac = undefined}) -> false; verify_algorithm(#alg{recv_mac = undefined}) -> false; verify_algorithm(#alg{encrypt = undefined}) -> false; verify_algorithm(#alg{decrypt = undefined}) -> false; verify_algorithm(#alg{compress = undefined}) -> false; verify_algorithm(#alg{decompress = undefined}) -> false; verify_algorithm(#alg{kex = 'diffie-hellman-group1-sha1'}) -> true; verify_algorithm(#alg{kex = 'diffie-hellman-group14-sha1'}) -> true; verify_algorithm(#alg{kex = 'diffie-hellman-group-exchange-sha1'}) -> true; verify_algorithm(#alg{kex = 'diffie-hellman-group-exchange-sha256'}) -> true; verify_algorithm(_) -> false. %%%---------------------------------------------------------------- %%% %%% Key exchange initialization %%% key_exchange_first_msg(Kex, Ssh0) when Kex == 'diffie-hellman-group1-sha1' ; Kex == 'diffie-hellman-group14-sha1' -> {G, P} = dh_group(Kex), {Private, Public} = dh_gen_key(G, P, 1024), %% Public = G^Private mod P (def) {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(Kex, Ssh0) when Kex == 'diffie-hellman-group-exchange-sha1' ; Kex == 'diffie-hellman-group-exchange-sha256' -> 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}}}. %%%---------------------------------------------------------------- %%% %%% diffie-hellman-group1-sha1 %%% diffie-hellman-group14-sha1 %%% handle_kexdh_init(#ssh_msg_kexdh_init{e = E}, Ssh0 = #ssh{algorithms = #alg{kex=Kex}}) -> %% server {G, P} = dh_group(Kex), if 1= {Private, Public} = dh_gen_key(G, P, 1024), K = dh_compute_key(G, P, E, Private), Key = get_host_key(Ssh0), H = kex_h(Ssh0, Key, E, Public, K), H_SIG = sign_host_key(Ssh0, Key, H), {SshPacket, Ssh1} = ssh_packet(#ssh_msg_kexdh_reply{public_host_key = Key, 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)}}; true -> throw({{error,bad_e_from_peer}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed, 'e' out of bounds", language = ""} }) end. 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) -> %% client if 1= K = dh_compute_key(G, P, F, Private), 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 -> throw({Error, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed", language = "en"} }) end; true -> throw({{error,bad_f_from_peer}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed, 'f' out of bounds", language = ""} }) end. %%%---------------------------------------------------------------- %%% %%% diffie-hellman-group-exchange-sha1 %%% handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request{min = Min, n = NBits, max = Max}, Ssh0=#ssh{opts=Opts}) when Min= %% server {G, P} = dh_gex_group(Min, NBits, Max, proplists:get_value(dh_gex_groups,Opts)), {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}}, keyex_info = {Min, Max, NBits} }}; handle_kex_dh_gex_request(_, _) -> throw({{error,bad_ssh_msg_kex_dh_gex_request}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed, bad values in ssh_msg_kex_dh_gex_request", language = ""} }). handle_kex_dh_gex_group(#ssh_msg_kex_dh_gex_group{p = P, g = G}, Ssh0) -> %% client {Private, Public} = dh_gen_key(G, P, 1024), {SshPacket, Ssh1} = ssh_packet(#ssh_msg_kex_dh_gex_init{e = Public}, Ssh0), % Pub = G^Priv mod P (def) {ok, SshPacket, Ssh1#ssh{keyex_key = {{Private, Public}, {G, P}}}}. handle_kex_dh_gex_init(#ssh_msg_kex_dh_gex_init{e = E}, #ssh{keyex_key = {{Private, Public}, {G, P}}, keyex_info = {Min, Max, NBits}} = Ssh0) -> %% server if 1= K = dh_compute_key(G, P, E, Private), if 1 HostKey = get_host_key(Ssh0), H = kex_h(Ssh0, HostKey, Min, NBits, Max, P, G, E, Public, K), H_SIG = sign_host_key(Ssh0, HostKey, H), {SshPacket, Ssh} = ssh_packet(#ssh_msg_kex_dh_gex_reply{public_host_key = HostKey, f = Public, h_sig = H_SIG}, Ssh0), {ok, SshPacket, Ssh#ssh{shared_secret = K, exchanged_hash = H, session_id = sid(Ssh, H) }}; true -> throw({{error,bad_K}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed, 'K' out of bounds", language = ""} }) end; true -> throw({{error,bad_e_from_peer}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed, 'e' out of bounds", language = ""} }) end. 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) -> %% client if 1= K = dh_compute_key(G, P, F, Private), if 1 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 -> throw(#ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed", language = ""} ) end; true -> throw({{error,bad_K}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed, 'K' out of bounds", language = ""} }) end; true -> throw({{error,bad_f_from_peer}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, description = "Key exchange failed, 'f' out of bounds", language = ""} }) end. %%%---------------------------------------------------------------- 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 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, case Mod:host_key(ALG#alg.hkey, Opts) of {ok, #'RSAPrivateKey'{} = Key} -> Key; {ok, #'DSAPrivateKey'{} = Key} -> Key; Result -> exit({error, {Result, unsupported_key_type}}) end. sign_host_key(_Ssh, #'RSAPrivateKey'{} = Private, H) -> Hash = sha, %% Option ?! _Signature = sign(H, Hash, Private); sign_host_key(_Ssh, #'DSAPrivateKey'{} = Private, H) -> Hash = sha, %% Option ?! _RawSignature = sign(H, Hash, Private). verify_host_key(SSH, PublicKey, Digest, Signature) -> case verify(Digest, sha, Signature, PublicKey) of false -> {error, bad_signature}; true -> known_host_key(SSH, PublicKey, public_algo(PublicKey)) end. public_algo(#'RSAPublicKey'{}) -> 'ssh-rsa'; public_algo({_, #'Dss-Parms'{}}) -> 'ssh-dss'. 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:is_host_key(Public, PeerName, Alg, Opts) of true -> ok; false -> 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) when length(CL) + length(SL) < 50 -> 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_all(_CL, _SL) -> throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR, description = "Too many algorithms", language = "en"}). 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_message:encode(Msg), Ssh = key_init(Ssh0#ssh.role, Ssh0, BinMsg), pack(BinMsg, Ssh); ssh_packet(Msg, Ssh) -> BinMsg = ssh_message: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. sign(SigData, Hash, #'DSAPrivateKey'{} = Key) -> DerSignature = public_key:sign(SigData, Hash, Key), #'Dss-Sig-Value'{r = R, s = S} = public_key:der_decode('Dss-Sig-Value', DerSignature), <>; sign(SigData, Hash, Key) -> public_key:sign(SigData, Hash, Key). verify(PlainText, Hash, Sig, {_, #'Dss-Parms'{}} = Key) -> <> = Sig, Signature = public_key:der_encode('Dss-Sig-Value', #'Dss-Sig-Value'{r = R, s = S}), public_key:verify(PlainText, Hash, Signature, Key); verify(PlainText, Hash, Sig, Key) -> public_key:verify(PlainText, Hash, Sig, Key). %% 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 %% diffie-hellman-group14-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_init(#ssh{encrypt = 'aes128-ctr', role = client} = Ssh) -> IV = hash(Ssh, "A", 128), <> = hash(Ssh, "C", 128), State = crypto:stream_init(aes_ctr, K, IV), {ok, Ssh#ssh{encrypt_keys = K, encrypt_block_size = 16, encrypt_ctx = State}}; encrypt_init(#ssh{encrypt = 'aes128-ctr', role = server} = Ssh) -> IV = hash(Ssh, "B", 128), <> = hash(Ssh, "D", 128), State = crypto:stream_init(aes_ctr, K, IV), {ok, Ssh#ssh{encrypt_keys = K, encrypt_block_size = 16, encrypt_ctx = State}}. 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:block_encrypt(des3_cbc, [K1,K2,K3], IV0, Data), IV = crypto:next_iv(des3_cbc, Enc), {Ssh#ssh{encrypt_ctx = IV}, Enc}; encrypt(#ssh{encrypt = 'aes128-cbc', encrypt_keys = K, encrypt_ctx = IV0} = Ssh, Data) -> Enc = crypto:block_encrypt(aes_cbc128, K,IV0,Data), IV = crypto:next_iv(aes_cbc, Enc), {Ssh#ssh{encrypt_ctx = IV}, Enc}; encrypt(#ssh{encrypt = 'aes128-ctr', encrypt_ctx = State0} = Ssh, Data) -> {State, Enc} = crypto:stream_encrypt(State0,Data), {Ssh#ssh{encrypt_ctx = State}, 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_init(#ssh{decrypt = 'aes128-ctr', role = client} = Ssh) -> IV = hash(Ssh, "B", 128), <> = hash(Ssh, "D", 128), State = crypto:stream_init(aes_ctr, K, IV), {ok, Ssh#ssh{decrypt_keys = K, decrypt_block_size = 16, decrypt_ctx = State}}; decrypt_init(#ssh{decrypt = 'aes128-ctr', role = server} = Ssh) -> IV = hash(Ssh, "A", 128), <> = hash(Ssh, "C", 128), State = crypto:stream_init(aes_ctr, K, IV), {ok, Ssh#ssh{decrypt_keys = K, decrypt_block_size = 16, decrypt_ctx = State}}. 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:block_decrypt(des3_cbc, [K1,K2,K3], IV0, Data), IV = crypto:next_iv(des3_cbc, Data), {Ssh#ssh{decrypt_ctx = IV}, Dec}; decrypt(#ssh{decrypt = 'aes128-cbc', decrypt_keys = Key, decrypt_ctx = IV0} = Ssh, Data) -> Dec = crypto:block_decrypt(aes_cbc128, Key,IV0,Data), IV = crypto:next_iv(aes_cbc, Data), {Ssh#ssh{decrypt_ctx = IV}, Dec}; decrypt(#ssh{decrypt = 'aes128-ctr', decrypt_ctx = State0} = Ssh, Data) -> {State, Enc} = crypto:stream_decrypt(State0,Data), {Ssh#ssh{decrypt_ctx = State}, Enc}. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% Compression %% %% none REQUIRED no compression %% zlib OPTIONAL ZLIB (LZ77) compression %% openssh_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_init(#ssh{compress = 'zlib@openssh.com'} = 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_final(#ssh{compress = 'zlib@openssh.com', authenticated = false} = Ssh) -> {ok, Ssh}; compress_final(#ssh{compress = 'zlib@openssh.com', compress_ctx = Context, authenticated = true} = 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)}; compress(#ssh{compress = 'zlib@openssh.com', authenticated = false} = Ssh, Data) -> {Ssh, Data}; compress(#ssh{compress = 'zlib@openssh.com', compress_ctx = Context, authenticated = true} = 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_init(#ssh{decompress = 'zlib@openssh.com'} = 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_final(#ssh{decompress = 'zlib@openssh.com', authenticated = false} = Ssh) -> {ok, Ssh}; decompress_final(#ssh{decompress = 'zlib@openssh.com', decompress_ctx = Context, authenticated = true} = 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)}; decompress(#ssh{decompress = 'zlib@openssh.com', authenticated = false} = Ssh, Data) -> {Ssh, Data}; decompress(#ssh{decompress = 'zlib@openssh.com', decompress_ctx = Context, authenticated = true} = 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:hmac(sha, Key, [<>, Data]); mac('hmac-sha1-96', Key, SeqNum, Data) -> crypto:hmac(sha, Key, [<>, Data], mac_digest_size('hmac-sha1-96')); mac('hmac-md5', Key, SeqNum, Data) -> crypto:hmac(md5, Key, [<>, Data]); mac('hmac-md5-96', Key, SeqNum, Data) -> crypto:hmac(md5, Key, [<>, Data], mac_digest_size('hmac-md5-96')); mac('hmac-sha2-256', Key, SeqNum, Data) -> crypto:hmac(sha256, Key, [<>, Data]). %% return N hash bytes (HASH) hash(SSH, Char, Bits) -> HASH = case SSH#ssh.kex of 'diffie-hellman-group1-sha1' -> fun(Data) -> crypto:hash(sha, Data) end; 'diffie-hellman-group14-sha1' -> fun(Data) -> crypto:hash(sha, Data) end; 'diffie-hellman-group-exchange-sha1' -> fun(Data) -> crypto:hash(sha, Data) end; 'diffie-hellman-group-exchange-sha256' -> fun(Data) -> crypto:hash(sha256, 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, Key, E, F, K) -> L = ssh_bits:encode([SSH#ssh.c_version, SSH#ssh.s_version, SSH#ssh.c_keyinit, SSH#ssh.s_keyinit, ssh_message:encode_host_key(Key), E,F,K], [string,string,binary,binary,binary, mpint,mpint,mpint]), crypto:hash(sha,L). kex_h(SSH, Key, 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, ssh_message:encode_host_key(Key), 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, ssh_message:encode_host_key(Key), Min, NBits, Max, Prime, Gen, E,F,K], Ts) end, crypto:hash(sha((SSH#ssh.algorithms)#alg.kex), L). sha('diffie-hellman-group-exchange-sha1') -> sha; sha('diffie-hellman-group-exchange-sha256') -> sha256. 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('hmac-sha2-256')-> 32*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('hmac-sha2-256') -> 32; mac_digest_size(none) -> 0. peer_name({Host, _}) -> Host. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %% Diffie-Hellman utils %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% dh_group('diffie-hellman-group1-sha1') -> ?dh_group1; dh_group('diffie-hellman-group14-sha1') -> ?dh_group14. dh_gex_default_groups() -> [{1024, ?dh_group1 }, {2048, ?dh_group14}, {3072, ?dh_group15}, {4096, ?dh_group16}]. dh_gex_group(Min, N, Max, undefined) -> dh_gex_group(Min, N, Max, dh_gex_default_groups()); dh_gex_group(Min, N, Max, Groups) -> %% First try to find an exact match. If not an exact match, select the largest possible. {_,Group} = lists:foldl( fun(_, {I,G}) when I==N -> %% If we have an exact match already: use that one {I,G}; ({I,G}, _) when I==N -> %% If we now found an exact match: use that very one {I,G}; ({I,G}, {Imax,_Gmax}) when Min=Imax -> % b) {I,G} is larger than current max %% A group within the limits and better than the one we have {I,G}; (_, IGmax) -> %% Keep the one we have IGmax end, {-1,undefined}, Groups), case Group of undefined -> throw(#ssh_msg_disconnect{ code = ?SSH_DISCONNECT_PROTOCOL_ERROR, description = "No possible diffie-hellman-group-exchange group found", language = ""}); _ -> Group end. dh_gen_key(G, P, _) -> {Public, Private} = crypto:generate_key(dh, [P, G]), {crypto:bytes_to_integer(Private), crypto:bytes_to_integer(Public)}. dh_compute_key(G, P, OthersPublic, MyPrivate) -> crypto:bytes_to_integer( crypto:compute_key(dh, OthersPublic, MyPrivate, [P,G]) ). %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %% Other utils %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 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.