diff options
Diffstat (limited to 'lib/ssh/src/ssh_transport.erl')
| -rw-r--r-- | lib/ssh/src/ssh_transport.erl | 760 |
1 files changed, 487 insertions, 273 deletions
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl index 8b65806dc6..a648c7af3d 100644 --- a/lib/ssh/src/ssh_transport.erl +++ b/lib/ssh/src/ssh_transport.erl @@ -31,10 +31,10 @@ -include("ssh.hrl"). -export([versions/2, hello_version_msg/1]). --export([next_seqnum/1, decrypt_first_block/2, decrypt_blocks/3, +-export([next_seqnum/1, supported_algorithms/0, supported_algorithms/1, default_algorithms/0, default_algorithms/1, - is_valid_mac/3, + handle_packet_part/4, handle_hello_version/1, key_exchange_init_msg/1, key_init/3, new_keys_message/1, @@ -45,9 +45,21 @@ handle_kex_ecdh_init/2, handle_kex_ecdh_reply/2, extract_public_key/1, - unpack/3, decompress/2, ssh_packet/2, pack/2, msg_data/1, + ssh_packet/2, pack/2, sign/3, verify/4]). +%%% For test suites +-export([pack/3]). +-export([decompress/2, decrypt_blocks/3, is_valid_mac/3 ]). % FIXME: remove + +-define(Estring(X), ?STRING((if is_binary(X) -> X; + is_list(X) -> list_to_binary(X); + X==undefined -> <<>> + end))). +-define(Empint(X), (ssh_bits:mpint(X))/binary ). +-define(Ebinary(X), ?STRING(X) ). +-define(Euint32(X), ?UINT32(X) ). + %%%---------------------------------------------------------------------------- %%% %%% There is a difference between supported and default algorithms. The @@ -66,10 +78,15 @@ default_algorithms() -> [{K,default_algorithms(K)} || K <- algo_classes()]. algo_classes() -> [kex, public_key, cipher, mac, compression]. -%% default_algorithms(kex) -> % Example of how to disable an algorithm -%% supported_algorithms(kex, ['ecdh-sha2-nistp521']); + +default_algorithms(cipher) -> + supported_algorithms(cipher, same(['AEAD_AES_128_GCM', + 'AEAD_AES_256_GCM'])); +default_algorithms(mac) -> + supported_algorithms(mac, same(['AEAD_AES_128_GCM', + 'AEAD_AES_256_GCM'])); default_algorithms(Alg) -> - supported_algorithms(Alg). + supported_algorithms(Alg, []). supported_algorithms() -> [{K,supported_algorithms(K)} || K <- algo_classes()]. @@ -97,19 +114,25 @@ supported_algorithms(public_key) -> supported_algorithms(cipher) -> same( select_crypto_supported( - [{'aes256-ctr', [{ciphers,{aes_ctr,256}}]}, - {'aes192-ctr', [{ciphers,{aes_ctr,192}}]}, - {'aes128-ctr', [{ciphers,{aes_ctr,128}}]}, - {'aes128-cbc', [{ciphers,aes_cbc128}]}, - {'3des-cbc', [{ciphers,des3_cbc}]} + [{'aes256-ctr', [{ciphers,{aes_ctr,256}}]}, + {'aes192-ctr', [{ciphers,{aes_ctr,192}}]}, + {'aes128-ctr', [{ciphers,{aes_ctr,128}}]}, + {'aes128-cbc', [{ciphers,aes_cbc128}]}, + {'[email protected]', [{ciphers,{aes_gcm,128}}]}, + {'[email protected]', [{ciphers,{aes_gcm,256}}]}, + {'AEAD_AES_128_GCM', [{ciphers,{aes_gcm,128}}]}, + {'AEAD_AES_256_GCM', [{ciphers,{aes_gcm,256}}]}, + {'3des-cbc', [{ciphers,des3_cbc}]} ] )); supported_algorithms(mac) -> same( select_crypto_supported( - [{'hmac-sha2-256', [{hashs,sha256}]}, - {'hmac-sha2-512', [{hashs,sha512}]}, - {'hmac-sha1', [{hashs,sha}]} + [{'hmac-sha2-256', [{hashs,sha256}]}, + {'hmac-sha2-512', [{hashs,sha512}]}, + {'hmac-sha1', [{hashs,sha}]}, + {'AEAD_AES_128_GCM', [{ciphers,{aes_gcm,128}}]}, + {'AEAD_AES_256_GCM', [{ciphers,{aes_gcm,256}}]} ] )); supported_algorithms(compression) -> @@ -118,46 +141,6 @@ supported_algorithms(compression) -> 'zlib' ]). -%% Dialyzer complains when not called...supported_algorithms(Key, [{client2server,BL1},{server2client,BL2}]) -> -%% Dialyzer complains when not called... [{client2server,As1},{server2client,As2}] = supported_algorithms(Key), -%% Dialyzer complains when not called... [{client2server,As1--BL1},{server2client,As2--BL2}]; -%% Dialyzer complains when not called...supported_algorithms(Key, BlackList) -> -%% Dialyzer complains when not called... supported_algorithms(Key) -- BlackList. - -select_crypto_supported(L) -> - Sup = [{ec_curve,crypto_supported_curves()} | crypto:supports()], - [Name || {Name,CryptoRequires} <- L, - crypto_supported(CryptoRequires, Sup)]. - -crypto_supported_curves() -> - try crypto:ec_curves() - catch _:_ -> [] - end. - -crypto_supported(Conditions, Supported) -> - lists:all( fun({Tag,CryptoName}) when is_atom(CryptoName) -> - crypto_name_supported(Tag,CryptoName,Supported); - ({Tag,{Name=aes_ctr,Len}}) when is_integer(Len) -> - crypto_name_supported(Tag,Name,Supported) andalso - ctr_len_supported(Name,Len) - end, Conditions). - -crypto_name_supported(Tag, CryptoName, Supported) -> - lists:member(CryptoName, proplists:get_value(Tag,Supported,[])). - -ctr_len_supported(Name, Len) -> - try - crypto:stream_encrypt(crypto:stream_init(Name, <<0:Len>>, <<0:128>>), <<"">>) - of - {_,X} -> is_binary(X) - catch - _:_ -> false - end. - - -same(Algs) -> [{client2server,Algs}, {server2client,Algs}]. - - %%%---------------------------------------------------------------------------- versions(client, Options)-> Vsn = proplists:get_value(vsn, Options, ?DEFAULT_CLIENT_VERSION), @@ -196,12 +179,6 @@ hello_version_msg(Data) -> next_seqnum(SeqNum) -> (SeqNum + 1) band 16#ffffffff. -decrypt_first_block(Bin, #ssh{decrypt_block_size = BlockSize} = Ssh0) -> - <<EncBlock:BlockSize/binary, EncData/binary>> = Bin, - {Ssh, <<?UINT32(PacketLen), _/binary>> = DecData} = - decrypt(Ssh0, EncBlock), - {Ssh, PacketLen, DecData, EncData}. - decrypt_blocks(Bin, Length, Ssh0) -> <<EncBlocks:Length/binary, EncData/binary>> = Bin, {Ssh, DecData} = decrypt(Ssh0, EncBlocks), @@ -441,19 +418,63 @@ handle_kexdh_reply(#ssh_msg_kexdh_reply{public_host_key = PeerPubHostKey, %%% %%% diffie-hellman-group-exchange-sha1 %%% -handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request{min = Min, +handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request{min = Min0, n = NBits, - max = Max}, - Ssh0=#ssh{opts=Opts}) when Min=<NBits, NBits=<Max -> + max = Max0}, + Ssh0=#ssh{opts=Opts}) when Min0=<NBits, NBits=<Max0 -> %% server - {G, P} = dh_gex_group(Min, NBits, Max, proplists:get_value(dh_gex_groups,Opts)), - {Public, Private} = generate_key(dh, [P,G]), - {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} - }}; + {Min, Max} = adjust_gex_min_max(Min0, Max0, Opts), + case public_key:dh_gex_group(Min, NBits, Max, + proplists:get_value(dh_gex_groups,Opts)) of + {ok, {_Sz, {G,P}}} -> + {Public, Private} = generate_key(dh, [P,G]), + {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} + }}; + {error,_} -> + throw(#ssh_msg_disconnect{ + code = ?SSH_DISCONNECT_PROTOCOL_ERROR, + description = "No possible diffie-hellman-group-exchange group found", + language = ""}) + end; + +handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request_old{n = NBits}, + Ssh0=#ssh{opts=Opts}) -> + %% server + %% + %% This message was in the draft-00 of rfc4419 + %% (https://tools.ietf.org/html/draft-ietf-secsh-dh-group-exchange-00) + %% In later drafts and the rfc is "is used for backward compatibility". + %% Unfortunatly the rfc does not specify how to treat the parameter n + %% if there is no group of that modulus length :( + %% The draft-00 however specifies that n is the "... number of bits + %% the subgroup should have at least". + %% Further, it says that "Servers and clients SHOULD support groups + %% with a modulus length of k bits, where 1024 <= k <= 8192." + %% + Min0 = NBits, + Max0 = 8192, + {Min, Max} = adjust_gex_min_max(Min0, Max0, Opts), + case public_key:dh_gex_group(Min, NBits, Max, + proplists:get_value(dh_gex_groups,Opts)) of + {ok, {_Sz, {G,P}}} -> + {Public, Private} = generate_key(dh, [P,G]), + {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 = {-1, -1, NBits} % flag for kex_h hash calc + }}; + {error,_} -> + throw(#ssh_msg_disconnect{ + code = ?SSH_DISCONNECT_PROTOCOL_ERROR, + description = "No possible diffie-hellman-group-exchange group found", + language = ""}) + end; + handle_kex_dh_gex_request(_, _) -> throw({{error,bad_ssh_msg_kex_dh_gex_request}, #ssh_msg_disconnect{ @@ -462,6 +483,26 @@ handle_kex_dh_gex_request(_, _) -> language = ""} }). + +adjust_gex_min_max(Min0, Max0, Opts) -> + case proplists:get_value(dh_gex_limits, Opts) of + undefined -> + {Min0, Max0}; + {Min1, Max1} -> + Min2 = max(Min0, Min1), + Max2 = min(Max0, Max1), + if + Min2 =< Max2 -> + {Min2, Max2}; + Max2 < Min2 -> + throw(#ssh_msg_disconnect{ + code = ?SSH_DISCONNECT_PROTOCOL_ERROR, + description = "No possible diffie-hellman-group-exchange group possible", + language = ""}) + end + end. + + handle_kex_dh_gex_group(#ssh_msg_kex_dh_gex_group{p = P, g = G}, Ssh0) -> %% client {Public, Private} = generate_key(dh, [P,G]), @@ -563,10 +604,11 @@ handle_kex_ecdh_init(#ssh_msg_kex_ecdh_init{q_c = PeerPublic}, Ssh0 = #ssh{algorithms = #alg{kex=Kex}}) -> %% at server Curve = ecdh_curve(Kex), - case ecdh_validate_public_key(PeerPublic, Curve) of - true -> - {MyPublic, MyPrivate} = generate_key(ecdh, Curve), - K = compute_key(ecdh, PeerPublic, MyPrivate, Curve), + {MyPublic, MyPrivate} = generate_key(ecdh, Curve), + try + compute_key(ecdh, PeerPublic, MyPrivate, Curve) + of + K -> MyPrivHostKey = get_host_key(Ssh0), MyPubHostKey = extract_public_key(MyPrivHostKey), H = kex_h(Ssh0, Curve, MyPubHostKey, PeerPublic, MyPublic, K), @@ -579,9 +621,9 @@ handle_kex_ecdh_init(#ssh_msg_kex_ecdh_init{q_c = PeerPublic}, {ok, SshPacket, Ssh1#ssh{keyex_key = {{MyPublic,MyPrivate},Curve}, shared_secret = K, exchanged_hash = H, - session_id = sid(Ssh1, H)}}; - - false -> + session_id = sid(Ssh1, H)}} + catch + _:_ -> throw({{error,invalid_peer_public_key}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, @@ -596,9 +638,10 @@ handle_kex_ecdh_reply(#ssh_msg_kex_ecdh_reply{public_host_key = PeerPubHostKey, #ssh{keyex_key = {{MyPublic,MyPrivate}, Curve}} = Ssh0 ) -> %% at client - case ecdh_validate_public_key(PeerPublic, Curve) of - true -> - K = compute_key(ecdh, PeerPublic, MyPrivate, Curve), + try + compute_key(ecdh, PeerPublic, MyPrivate, Curve) + of + K -> H = kex_h(Ssh0, Curve, PeerPubHostKey, MyPublic, PeerPublic, K), case verify_host_key(Ssh0, PeerPubHostKey, H, H_SIG) of ok -> @@ -613,9 +656,9 @@ handle_kex_ecdh_reply(#ssh_msg_kex_ecdh_reply{public_host_key = PeerPubHostKey, description = "Key exchange failed", language = ""} }) - end; - - false -> + end + catch + _:_ -> throw({{error,invalid_peer_public_key}, #ssh_msg_disconnect{ code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED, @@ -626,62 +669,6 @@ handle_kex_ecdh_reply(#ssh_msg_kex_ecdh_reply{public_host_key = PeerPubHostKey, %%%---------------------------------------------------------------- -%%% -%%% Standards for Efficient Cryptography Group, "Elliptic Curve Cryptography", SEC 1 -%%% Section 3.2.2.1 -%%% - -ecdh_validate_public_key(Key, Curve) -> - case key_size(Curve) of - undefined -> - false; - - Sz -> - case dec_key(Key, Sz) of - {ok,Q} -> - case crypto:ec_curve(Curve) of - {{prime_field,P}, {A, B, _Seed}, - _P0Bin, _OrderBin, _CoFactorBin} -> - on_curve(Q, bin2int(A), bin2int(B), bin2int(P)) - end; - - {error,compressed_not_implemented} -> % Be a bit generous... - true; - - _Error -> - false - end - end. - - -on_curve({X,Y}, A, B, P) when 0 =< X,X =< (P-1), - 0 =< Y,Y =< (P-1) -> - %% Section 3.2.2.1, point 2 - (Y*Y) rem P == (X*X*X + A*X + B) rem P; -on_curve(_, _, _, _) -> - false. - - -bin2int(B) -> - Sz = erlang:bit_size(B), - <<I:Sz/big-unsigned-integer>> = B, - I. - -key_size(secp256r1) -> 256; -key_size(secp384r1) -> 384; -key_size(secp521r1) -> 528; % Round 521 up to closest 8-bits. -key_size(_) -> undefined. - - -dec_key(Key, NBits) -> - Size = 8 + 2*NBits, - case <<Key:Size>> of - <<4:8, X:NBits, Y:NBits>> -> {ok,{X,Y}}; - <<4:8, _/binary>> -> {error,bad_format}; - _ -> {error,compressed_not_implemented} - end. - -%%%---------------------------------------------------------------- handle_new_keys(#ssh_msg_newkeys{}, Ssh0) -> try install_alg(Ssh0) of #ssh{} = Ssh -> @@ -781,8 +768,12 @@ known_host_key(#ssh{opts = Opts, key_cb = Mod, peer = Peer} = Ssh, %% 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), + {Encrypt0, Decrypt0} = select_encrypt_decrypt(Role, Client, Server), + {SendMac0, RecvMac0} = select_send_recv_mac(Role, Client, Server), + + {Encrypt, SendMac} = aead_gcm_simultan(Encrypt0, SendMac0), + {Decrypt, RecvMac} = aead_gcm_simultan(Decrypt0, RecvMac0), + {Compression, Decompression} = select_compression_decompression(Role, Client, Server), @@ -813,6 +804,38 @@ select_algorithm(Role, Client, Server) -> s_lng = S_Lng}, {ok, Alg}. + +%%% It is an agreed problem with RFC 5674 that if the selection is +%%% Cipher = AEAD_AES_x_GCM and +%%% Mac = AEAD_AES_y_GCM (where x =/= y) +%%% then it is undefined what length should be selected. +%%% +%%% If only one of the two lengths (128,256) is available, I claim that +%%% there is no such ambiguity. + +%%% From https://anongit.mindrot.org/openssh.git/plain/PROTOCOL +%%% (read Nov 20, 2015) +%%% 1.6 transport: AES-GCM +%%% +%%% OpenSSH supports the AES-GCM algorithm as specified in RFC 5647. +%%% Because of problems with the specification of the key exchange +%%% the behaviour of OpenSSH differs from the RFC as follows: +%%% +%%% AES-GCM is only negotiated as the cipher algorithms +%%% "[email protected]" or "[email protected]" and never as +%%% an MAC algorithm. Additionally, if AES-GCM is selected as the cipher +%%% the exchanged MAC algorithms are ignored and there doesn't have to be +%%% a matching MAC. + +aead_gcm_simultan('[email protected]', _) -> {'AEAD_AES_128_GCM', 'AEAD_AES_128_GCM'}; +aead_gcm_simultan('[email protected]', _) -> {'AEAD_AES_256_GCM', 'AEAD_AES_256_GCM'}; +aead_gcm_simultan('AEAD_AES_128_GCM', _) -> {'AEAD_AES_128_GCM', 'AEAD_AES_128_GCM'}; +aead_gcm_simultan('AEAD_AES_256_GCM', _) -> {'AEAD_AES_256_GCM', 'AEAD_AES_256_GCM'}; +aead_gcm_simultan(_, 'AEAD_AES_128_GCM') -> {'AEAD_AES_128_GCM', 'AEAD_AES_128_GCM'}; +aead_gcm_simultan(_, 'AEAD_AES_256_GCM') -> {'AEAD_AES_256_GCM', 'AEAD_AES_256_GCM'}; +aead_gcm_simultan(Cipher, Mac) -> {Cipher,Mac}. + + select_encrypt_decrypt(client, Client, Server) -> Encrypt = select(Client#ssh_msg_kexinit.encryption_algorithms_client_to_server, @@ -847,18 +870,18 @@ 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 = + Decompression = select(Client#ssh_msg_kexinit.compression_algorithms_server_to_client, Server#ssh_msg_kexinit.compression_algorithms_server_to_client), - {Compression, Decomprssion}; + {Compression, Decompression}; select_compression_decompression(server, Client, Server) -> - Decomprssion = + Decompression = 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}. + {Compression, Decompression}. install_alg(SSH) -> SSH1 = alg_final(SSH), @@ -929,13 +952,45 @@ 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, - random_length_padding = RandomLengthPadding} - = Ssh0) when is_binary(Data0) -> - {Ssh1, Data} = compress(Ssh0, Data0), - PL = (BlockSize - ((4 + 1 + size(Data)) rem BlockSize)) rem BlockSize, +pack(Data, Ssh=#ssh{}) -> + pack(Data, Ssh, 0). + +%%% Note: pack/3 is only to be called from tests that wants +%%% to deliberetly send packets with wrong PacketLength! +%%% Use pack/2 for all other purposes! +pack(PlainText, + #ssh{send_sequence = SeqNum, + send_mac = MacAlg, + send_mac_key = MacKey, + encrypt = CryptoAlg} = Ssh0, PacketLenDeviationForTests) when is_binary(PlainText) -> + + {Ssh1, CompressedPlainText} = compress(Ssh0, PlainText), + {EcryptedPacket, MAC, Ssh3} = + case pkt_type(CryptoAlg) of + common -> + PaddingLen = padding_length(4+1+size(CompressedPlainText), Ssh0), + Padding = ssh_bits:random(PaddingLen), + PlainPacketLen = 1 + PaddingLen + size(CompressedPlainText) + PacketLenDeviationForTests, + PlainPacketData = <<?UINT32(PlainPacketLen),?BYTE(PaddingLen), CompressedPlainText/binary, Padding/binary>>, + {Ssh2, EcryptedPacket0} = encrypt(Ssh1, PlainPacketData), + MAC0 = mac(MacAlg, MacKey, SeqNum, PlainPacketData), + {EcryptedPacket0, MAC0, Ssh2}; + aead -> + PaddingLen = padding_length(1+size(CompressedPlainText), Ssh0), + Padding = ssh_bits:random(PaddingLen), + PlainPacketLen = 1 + PaddingLen + size(CompressedPlainText) + PacketLenDeviationForTests, + PlainPacketData = <<?BYTE(PaddingLen), CompressedPlainText/binary, Padding/binary>>, + {Ssh2, {EcryptedPacket0,MAC0}} = encrypt(Ssh1, {<<?UINT32(PlainPacketLen)>>,PlainPacketData}), + {<<?UINT32(PlainPacketLen),EcryptedPacket0/binary>>, MAC0, Ssh2} + end, + FinalPacket = [EcryptedPacket, MAC], + Ssh = Ssh3#ssh{send_sequence = (SeqNum+1) band 16#ffffffff}, + {FinalPacket, Ssh}. + + +padding_length(Size, #ssh{encrypt_block_size = BlockSize, + random_length_padding = RandomLengthPadding}) -> + PL = (BlockSize - (Size rem BlockSize)) rem BlockSize, MinPaddingLen = if PL < 4 -> PL + BlockSize; true -> PL end, @@ -944,45 +999,91 @@ pack(Data0, #ssh{encrypt_block_size = BlockSize, ExtraPaddingLen = try crypto:rand_uniform(0,MaxExtraBlocks)*PadBlockSize catch _:_ -> 0 end, - PaddingLen = MinPaddingLen + ExtraPaddingLen, - Padding = ssh_bits:random(PaddingLen), - PacketLen = 1 + PaddingLen + size(Data), - PacketData = <<?UINT32(PacketLen),?BYTE(PaddingLen), - Data/binary, Padding/binary>>, - {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 -> - <<NoMac0:SshLength/binary, - Rest0/binary>> = EncodedSoFar, - {NoMac0, <<>>, Rest0}; - _ -> - <<NoMac0:SshLength/binary, - Mac0:MacSize/binary, - Rest0/binary>> = EncodedSoFar, - {NoMac0, Mac0, Rest0} - end, - {Ssh1, DecData, <<>>} = - case SshLength of - 0 -> - {Ssh0, <<>>, <<>>}; - _ -> - decrypt_blocks(NoMac, SshLength, Ssh0) - end, - {Ssh1, DecData, Rest, Mac}. + MinPaddingLen + ExtraPaddingLen. + + + +handle_packet_part(<<>>, Encrypted0, undefined, #ssh{decrypt = CryptoAlg} = Ssh0) -> + %% New ssh packet + case get_length(pkt_type(CryptoAlg), Encrypted0, Ssh0) of + get_more -> + %% too short to get the length + {get_more, <<>>, Encrypted0, undefined, Ssh0}; + + {ok, PacketLen, _, _, _} when PacketLen > ?SSH_MAX_PACKET_SIZE -> + %% far too long message than expected + {error, {exceeds_max_size,PacketLen}}; + + {ok, PacketLen, Decrypted, Encrypted1, + #ssh{recv_mac_size = MacSize} = Ssh1} -> + %% enough bytes so we got the length and can calculate how many + %% more bytes to expect for a full packet + TotalNeeded = (4 + PacketLen + MacSize), + handle_packet_part(Decrypted, Encrypted1, TotalNeeded, Ssh1) + end; + +handle_packet_part(DecryptedPfx, EncryptedBuffer, TotalNeeded, Ssh0) + when (size(DecryptedPfx)+size(EncryptedBuffer)) < TotalNeeded -> + %% need more bytes to finalize the packet + {get_more, DecryptedPfx, EncryptedBuffer, TotalNeeded, Ssh0}; + +handle_packet_part(DecryptedPfx, EncryptedBuffer, TotalNeeded, + #ssh{recv_mac_size = MacSize, + decrypt = CryptoAlg} = Ssh0) -> + %% enough bytes to decode the packet. + DecryptLen = TotalNeeded - size(DecryptedPfx) - MacSize, + <<EncryptedSfx:DecryptLen/binary, Mac:MacSize/binary, NextPacketBytes/binary>> = EncryptedBuffer, + case pkt_type(CryptoAlg) of + common -> + {Ssh1, DecryptedSfx} = decrypt(Ssh0, EncryptedSfx), + DecryptedPacket = <<DecryptedPfx/binary, DecryptedSfx/binary>>, + case is_valid_mac(Mac, DecryptedPacket, Ssh1) of + false -> + {bad_mac, Ssh1}; + true -> + {Ssh, DecompressedPayload} = decompress(Ssh1, payload(DecryptedPacket)), + {decoded, DecompressedPayload, NextPacketBytes, Ssh} + end; + aead -> + PacketLenBin = DecryptedPfx, + case decrypt(Ssh0, {PacketLenBin,EncryptedSfx,Mac}) of + {Ssh1, error} -> + {bad_mac, Ssh1}; + {Ssh1, DecryptedSfx} -> + DecryptedPacket = <<DecryptedPfx/binary, DecryptedSfx/binary>>, + {Ssh, DecompressedPayload} = decompress(Ssh1, payload(DecryptedPacket)), + {decoded, DecompressedPayload, NextPacketBytes, Ssh} + end + end. + + +get_length(common, EncryptedBuffer, #ssh{decrypt_block_size = BlockSize} = Ssh0) -> + case size(EncryptedBuffer) >= erlang:max(8, BlockSize) of + true -> + <<EncBlock:BlockSize/binary, EncryptedRest/binary>> = EncryptedBuffer, + {Ssh, + <<?UINT32(PacketLen),_/binary>> = Decrypted} = decrypt(Ssh0, EncBlock), + {ok, PacketLen, Decrypted, EncryptedRest, Ssh}; + false -> + get_more + end; +get_length(aead, EncryptedBuffer, Ssh) -> + case size(EncryptedBuffer) >= 4 of + true -> + <<?UINT32(PacketLen), EncryptedRest/binary>> = EncryptedBuffer, + {ok, PacketLen, <<?UINT32(PacketLen)>>, EncryptedRest, Ssh}; + false -> + get_more + end. -msg_data(PacketData) -> - <<Len:32, PaddingLen:8, _/binary>> = PacketData, - DataLen = Len - PaddingLen - 1, - <<_:32, _:8, Data:DataLen/binary, - _:PaddingLen/binary>> = PacketData, - Data. +pkt_type('AEAD_AES_128_GCM') -> aead; +pkt_type('AEAD_AES_256_GCM') -> aead; +pkt_type(_) -> common. + +payload(<<PacketLen:32, PaddingLen:8, PayloadAndPadding/binary>>) -> + PayloadLen = PacketLen - PaddingLen - 1, + <<Payload:PayloadLen/binary, _/binary>> = PayloadAndPadding, + Payload. sign(SigData, Hash, #'DSAPrivateKey'{} = Key) -> DerSignature = public_key:sign(SigData, Hash, Key), @@ -991,7 +1092,7 @@ sign(SigData, Hash, #'DSAPrivateKey'{} = Key) -> sign(SigData, Hash, Key = #'ECPrivateKey'{}) -> DerEncodedSign = public_key:sign(SigData, Hash, Key), #'ECDSA-Sig-Value'{r=R, s=S} = public_key:der_decode('ECDSA-Sig-Value', DerEncodedSign), - ssh_bits:encode([R,S], [mpint,mpint]); + <<?Empint(R),?Empint(S)>>; sign(SigData, Hash, Key) -> public_key:sign(SigData, Hash, Key). @@ -1008,6 +1109,7 @@ verify(PlainText, Hash, Sig, {#'ECPoint'{},_} = Key) -> verify(PlainText, Hash, Sig, Key) -> public_key:verify(PlainText, Hash, Sig, Key). + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %% Encryption @@ -1016,6 +1118,30 @@ verify(PlainText, Hash, Sig, Key) -> encrypt_init(#ssh{encrypt = none} = Ssh) -> {ok, Ssh}; +encrypt_init(#ssh{encrypt = 'AEAD_AES_128_GCM', role = client} = Ssh) -> + IV = hash(Ssh, "A", 12*8), + <<K:16/binary>> = hash(Ssh, "C", 128), + {ok, Ssh#ssh{encrypt_keys = K, + encrypt_block_size = 16, + encrypt_ctx = IV}}; +encrypt_init(#ssh{encrypt = 'AEAD_AES_128_GCM', role = server} = Ssh) -> + IV = hash(Ssh, "B", 12*8), + <<K:16/binary>> = hash(Ssh, "D", 128), + {ok, Ssh#ssh{encrypt_keys = K, + encrypt_block_size = 16, + encrypt_ctx = IV}}; +encrypt_init(#ssh{encrypt = 'AEAD_AES_256_GCM', role = client} = Ssh) -> + IV = hash(Ssh, "A", 12*8), + <<K:32/binary>> = hash(Ssh, "C", 256), + {ok, Ssh#ssh{encrypt_keys = K, + encrypt_block_size = 16, + encrypt_ctx = IV}}; +encrypt_init(#ssh{encrypt = 'AEAD_AES_256_GCM', role = server} = Ssh) -> + IV = hash(Ssh, "B", 12*8), + <<K:32/binary>> = hash(Ssh, "D", 256), + {ok, Ssh#ssh{encrypt_keys = K, + encrypt_block_size = 16, + encrypt_ctx = IV}}; encrypt_init(#ssh{encrypt = '3des-cbc', role = client} = Ssh) -> IV = hash(Ssh, "A", 64), <<K1:8/binary, K2:8/binary, K3:8/binary>> = hash(Ssh, "C", 192), @@ -1092,6 +1218,18 @@ encrypt_final(Ssh) -> encrypt(#ssh{encrypt = none} = Ssh, Data) -> {Ssh, Data}; +encrypt(#ssh{encrypt = 'AEAD_AES_128_GCM', + encrypt_keys = K, + encrypt_ctx = IV0} = Ssh, Data={_AAD,_Ptext}) -> + Enc = {_Ctext,_Ctag} = crypto:block_encrypt(aes_gcm, K, IV0, Data), + IV = next_gcm_iv(IV0), + {Ssh#ssh{encrypt_ctx = IV}, Enc}; +encrypt(#ssh{encrypt = 'AEAD_AES_256_GCM', + encrypt_keys = K, + encrypt_ctx = IV0} = Ssh, Data={_AAD,_Ptext}) -> + Enc = {_Ctext,_Ctag} = crypto:block_encrypt(aes_gcm, K, IV0, Data), + IV = next_gcm_iv(IV0), + {Ssh#ssh{encrypt_ctx = IV}, Enc}; encrypt(#ssh{encrypt = '3des-cbc', encrypt_keys = {K1,K2,K3}, encrypt_ctx = IV0} = Ssh, Data) -> @@ -1124,6 +1262,30 @@ encrypt(#ssh{encrypt = 'aes256-ctr', decrypt_init(#ssh{decrypt = none} = Ssh) -> {ok, Ssh}; +decrypt_init(#ssh{decrypt = 'AEAD_AES_128_GCM', role = client} = Ssh) -> + IV = hash(Ssh, "B", 12*8), + <<K:16/binary>> = hash(Ssh, "D", 128), + {ok, Ssh#ssh{decrypt_keys = K, + decrypt_block_size = 16, + decrypt_ctx = IV}}; +decrypt_init(#ssh{decrypt = 'AEAD_AES_128_GCM', role = server} = Ssh) -> + IV = hash(Ssh, "A", 12*8), + <<K:16/binary>> = hash(Ssh, "C", 128), + {ok, Ssh#ssh{decrypt_keys = K, + decrypt_block_size = 16, + decrypt_ctx = IV}}; +decrypt_init(#ssh{decrypt = 'AEAD_AES_256_GCM', role = client} = Ssh) -> + IV = hash(Ssh, "B", 12*8), + <<K:32/binary>> = hash(Ssh, "D", 256), + {ok, Ssh#ssh{decrypt_keys = K, + decrypt_block_size = 16, + decrypt_ctx = IV}}; +decrypt_init(#ssh{decrypt = 'AEAD_AES_256_GCM', role = server} = Ssh) -> + IV = hash(Ssh, "A", 12*8), + <<K:32/binary>> = hash(Ssh, "C", 256), + {ok, Ssh#ssh{decrypt_keys = K, + decrypt_block_size = 16, + decrypt_ctx = IV}}; decrypt_init(#ssh{decrypt = '3des-cbc', role = client} = Ssh) -> {IV, KD} = {hash(Ssh, "B", 64), hash(Ssh, "D", 192)}, @@ -1198,8 +1360,22 @@ decrypt_final(Ssh) -> decrypt_ctx = undefined, decrypt_block_size = 8}}. +decrypt(Ssh, <<>>) -> + {Ssh, <<>>}; decrypt(#ssh{decrypt = none} = Ssh, Data) -> {Ssh, Data}; +decrypt(#ssh{decrypt = 'AEAD_AES_128_GCM', + decrypt_keys = K, + decrypt_ctx = IV0} = Ssh, Data = {_AAD,_Ctext,_Ctag}) -> + Dec = crypto:block_decrypt(aes_gcm, K, IV0, Data), % Dec = PlainText | error + IV = next_gcm_iv(IV0), + {Ssh#ssh{decrypt_ctx = IV}, Dec}; +decrypt(#ssh{decrypt = 'AEAD_AES_256_GCM', + decrypt_keys = K, + decrypt_ctx = IV0} = Ssh, Data = {_AAD,_Ctext,_Ctag}) -> + Dec = crypto:block_decrypt(aes_gcm, K, IV0, Data), % Dec = PlainText | error + IV = next_gcm_iv(IV0), + {Ssh#ssh{decrypt_ctx = IV}, Dec}; decrypt(#ssh{decrypt = '3des-cbc', decrypt_keys = Keys, decrypt_ctx = IV0} = Ssh, Data) -> {K1, K2, K3} = Keys, @@ -1224,6 +1400,10 @@ decrypt(#ssh{decrypt = 'aes256-ctr', {State, Enc} = crypto:stream_decrypt(State0,Data), {Ssh#ssh{decrypt_ctx = State}, Enc}. + +next_gcm_iv(<<Fixed:32, InvCtr:64>>) -> <<Fixed:32, (InvCtr+1):64>>. + + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% Compression %% @@ -1312,28 +1492,42 @@ decompress(#ssh{decompress = '[email protected]', decompress_ctx = Context, authe %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 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 }} + case pkt_type(SSH#ssh.send_mac) of + common -> + 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; + aead -> + %% Not applicable + {ok, SSH} end. send_mac_final(SSH) -> - {ok, SSH#ssh { send_mac = none, send_mac_key = undefined }}. + {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 }} + case pkt_type(SSH#ssh.recv_mac) of + common -> + 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; + aead -> + %% Not applicable + {ok, SSH} end. recv_mac_final(SSH) -> @@ -1398,42 +1592,32 @@ hash(K, H, Ki, N, HASH) -> kex_h(SSH, Key, E, F, K) -> KeyBin = public_key:ssh_encode(Key, ssh2_pubkey), - L = ssh_bits:encode([SSH#ssh.c_version, SSH#ssh.s_version, - SSH#ssh.c_keyinit, SSH#ssh.s_keyinit, - KeyBin, E,F,K], - [string,string,binary,binary,binary, - mpint,mpint,mpint]), + L = <<?Estring(SSH#ssh.c_version), ?Estring(SSH#ssh.s_version), + ?Ebinary(SSH#ssh.c_keyinit), ?Ebinary(SSH#ssh.s_keyinit), ?Ebinary(KeyBin), + ?Empint(E), ?Empint(F), ?Empint(K)>>, crypto:hash(sha((SSH#ssh.algorithms)#alg.kex), L). -%% crypto:hash(sha,L). kex_h(SSH, Curve, Key, Q_c, Q_s, K) -> KeyBin = public_key:ssh_encode(Key, ssh2_pubkey), - L = ssh_bits:encode([SSH#ssh.c_version, SSH#ssh.s_version, - SSH#ssh.c_keyinit, SSH#ssh.s_keyinit, - KeyBin, Q_c, Q_s, K], - [string,string,binary,binary,binary, - mpint,mpint,mpint]), + L = <<?Estring(SSH#ssh.c_version), ?Estring(SSH#ssh.s_version), + ?Ebinary(SSH#ssh.c_keyinit), ?Ebinary(SSH#ssh.s_keyinit), ?Ebinary(KeyBin), + ?Empint(Q_c), ?Empint(Q_s), ?Empint(K)>>, crypto:hash(sha(Curve), L). kex_h(SSH, Key, Min, NBits, Max, Prime, Gen, E, F, K) -> + KeyBin = public_key:ssh_encode(Key, ssh2_pubkey), L = if Min==-1; Max==-1 -> - KeyBin = public_key:ssh_encode(Key, ssh2_pubkey), - 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, - KeyBin, NBits, Prime, Gen, E,F,K], - Ts); + %% flag from 'ssh_msg_kex_dh_gex_request_old' + %% It was like this before that message was supported, + %% why? + <<?Estring(SSH#ssh.c_version), ?Estring(SSH#ssh.s_version), + ?Ebinary(SSH#ssh.c_keyinit), ?Ebinary(SSH#ssh.s_keyinit), ?Ebinary(KeyBin), + ?Empint(E), ?Empint(F), ?Empint(K)>>; true -> - KeyBin = public_key:ssh_encode(Key, ssh2_pubkey), - 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, - KeyBin, Min, NBits, Max, - Prime, Gen, E,F,K], Ts) + <<?Estring(SSH#ssh.c_version), ?Estring(SSH#ssh.s_version), + ?Ebinary(SSH#ssh.c_keyinit), ?Ebinary(SSH#ssh.s_keyinit), ?Ebinary(KeyBin), + ?Euint32(Min), ?Euint32(NBits), ?Euint32(Max), + ?Empint(Prime), ?Empint(Gen), ?Empint(E), ?Empint(F), ?Empint(K)>> end, crypto:hash(sha((SSH#ssh.algorithms)#alg.kex), L). @@ -1464,6 +1648,8 @@ mac_digest_size('hmac-md5') -> 20; mac_digest_size('hmac-md5-96') -> 12; mac_digest_size('hmac-sha2-256') -> 32; mac_digest_size('hmac-sha2-512') -> 64; +mac_digest_size('AEAD_AES_128_GCM') -> 16; +mac_digest_size('AEAD_AES_256_GCM') -> 16; mac_digest_size(none) -> 0. peer_name({Host, _}) -> @@ -1475,44 +1661,10 @@ peer_name({Host, _}) -> %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -dh_group('diffie-hellman-group1-sha1') -> element(2, ?dh_group1); -dh_group('diffie-hellman-group14-sha1') -> element(2, ?dh_group14). - -dh_gex_default_groups() -> ?dh_default_groups. - - -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. - {_Size,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=<I,I=<Max, % a) {I,G} fullfills the requirements - I>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_group('diffie-hellman-group1-sha1') -> ?dh_group1; +dh_group('diffie-hellman-group14-sha1') -> ?dh_group14. +%%%---------------------------------------------------------------- generate_key(Algorithm, Args) -> {Public,Private} = crypto:generate_key(Algorithm, Args), {crypto:bytes_to_integer(Public), crypto:bytes_to_integer(Private)}. @@ -1527,6 +1679,68 @@ ecdh_curve('ecdh-sha2-nistp256') -> secp256r1; ecdh_curve('ecdh-sha2-nistp384') -> secp384r1; ecdh_curve('ecdh-sha2-nistp521') -> secp521r1. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% +%% Utils for default_algorithms/1 and supported_algorithms/1 +%% +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +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 = [{ec_curve,crypto_supported_curves()} | crypto:supports()], + [Name || {Name,CryptoRequires} <- L, + crypto_supported(CryptoRequires, Sup)]. + +crypto_supported_curves() -> + try crypto:ec_curves() + catch _:_ -> [] + end. + +crypto_supported(Conditions, Supported) -> + lists:all( fun({Tag,CryptoName}) when is_atom(CryptoName) -> + crypto_name_supported(Tag,CryptoName,Supported); + ({Tag,{Name,Len}}) when is_integer(Len) -> + crypto_name_supported(Tag,Name,Supported) andalso + len_supported(Name,Len) + end, Conditions). + +crypto_name_supported(Tag, CryptoName, Supported) -> + lists:member(CryptoName, proplists:get_value(Tag,Supported,[])). + +len_supported(Name, Len) -> + try + case Name of + aes_ctr -> + {_, <<_/binary>>} = + %% Test encryption + crypto:stream_encrypt(crypto:stream_init(Name, <<0:Len>>, <<0:128>>), <<"">>); + aes_gcm -> + {<<_/binary>>, <<_/binary>>} = + crypto:block_encrypt(Name, + _Key = <<0:Len>>, + _IV = <<0:12/unsigned-unit:8>>, + {<<"AAD">>,"PT"}) + end + of + _ -> true + catch + _:_ -> false + end. + + +same(Algs) -> [{client2server,Algs}, {server2client,Algs}]. + + +%% default_algorithms(kex) -> % Example of how to disable an algorithm +%% supported_algorithms(kex, ['ecdh-sha2-nistp521']); + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% %% Other utils |