From 80a162cdf59f6a3826fba0cc0d3b861451a6b102 Mon Sep 17 00:00:00 2001 From: Hans Nilsson Date: Thu, 26 Jan 2017 22:48:13 +0100 Subject: ssh: optimize kex dh_gex using new crypto functionality --- lib/ssh/src/ssh_connection_handler.erl | 6 +- lib/ssh/src/ssh_transport.erl | 123 ++++++++++++++++++++++++++------- 2 files changed, 102 insertions(+), 27 deletions(-) (limited to 'lib') diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl index 8718e92fa2..4496c657c3 100644 --- a/lib/ssh/src/ssh_connection_handler.erl +++ b/lib/ssh/src/ssh_connection_handler.erl @@ -609,13 +609,15 @@ handle_event(_, #ssh_msg_kexdh_reply{} = Msg, {key_exchange,client,ReNeg}, D) -> %%%---- diffie-hellman group exchange handle_event(_, #ssh_msg_kex_dh_gex_request{} = Msg, {key_exchange,server,ReNeg}, D) -> - {ok, GexGroup, Ssh} = ssh_transport:handle_kex_dh_gex_request(Msg, D#data.ssh_params), + {ok, GexGroup, Ssh1} = ssh_transport:handle_kex_dh_gex_request(Msg, D#data.ssh_params), send_bytes(GexGroup, D), + Ssh = ssh_transport:parallell_gen_key(Ssh1), {next_state, {key_exchange_dh_gex_init,server,ReNeg}, D#data{ssh_params=Ssh}}; handle_event(_, #ssh_msg_kex_dh_gex_request_old{} = Msg, {key_exchange,server,ReNeg}, D) -> - {ok, GexGroup, Ssh} = ssh_transport:handle_kex_dh_gex_request(Msg, D#data.ssh_params), + {ok, GexGroup, Ssh1} = ssh_transport:handle_kex_dh_gex_request(Msg, D#data.ssh_params), send_bytes(GexGroup, D), + Ssh = ssh_transport:parallell_gen_key(Ssh1), {next_state, {key_exchange_dh_gex_init,server,ReNeg}, D#data{ssh_params=Ssh}}; handle_event(_, #ssh_msg_kex_dh_gex_group{} = Msg, {key_exchange,client,ReNeg}, D) -> diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl index 5e8efa2af7..a7cc4cd52c 100644 --- a/lib/ssh/src/ssh_transport.erl +++ b/lib/ssh/src/ssh_transport.erl @@ -44,6 +44,7 @@ handle_kexdh_reply/2, handle_kex_ecdh_init/2, handle_kex_ecdh_reply/2, + parallell_gen_key/1, extract_public_key/1, ssh_packet/2, pack/2, sha/1, sign/3, verify/4]). @@ -296,9 +297,6 @@ handle_kexinit_msg(#ssh_msg_kexinit{} = CounterPart, #ssh_msg_kexinit{} = Own, 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; @@ -316,17 +314,29 @@ verify_algorithm(#alg{kex = Kex}) -> lists:member(Kex, supported_algorithms(kex) key_exchange_first_msg(Kex, Ssh0) when Kex == 'diffie-hellman-group1-sha1' ; Kex == 'diffie-hellman-group14-sha1' -> {G, P} = dh_group(Kex), - {Public, Private} = generate_key(dh, [P,G]), + Sz = dh_bits(Ssh0#ssh.algorithms), + {Public, Private} = generate_key(dh, [P,G,2*Sz]), {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=#ssh{opts=Opts}) when Kex == 'diffie-hellman-group-exchange-sha1' ; Kex == 'diffie-hellman-group-exchange-sha256' -> - {Min,NBits,Max} = + {Min,NBits0,Max} = proplists:get_value(dh_gex_limits, Opts, {?DEFAULT_DH_GROUP_MIN, ?DEFAULT_DH_GROUP_NBITS, ?DEFAULT_DH_GROUP_MAX}), + DhBits = dh_bits(Ssh0#ssh.algorithms), + NBits1 = + %% NIST Special Publication 800-57 Part 1 Revision 4: Recommendation for Key Management + if + DhBits =< 112 -> 2048; + DhBits =< 128 -> 3072; + DhBits =< 192 -> 7680; + true -> 8192 + end, + NBits = min(max(max(NBits0,NBits1),Min), Max), + {SshPacket, Ssh1} = ssh_packet(#ssh_msg_kex_dh_gex_request{min = Min, n = NBits, @@ -350,12 +360,13 @@ key_exchange_first_msg(Kex, Ssh0) when Kex == 'ecdh-sha2-nistp256' ; %%% diffie-hellman-group14-sha1 %%% handle_kexdh_init(#ssh_msg_kexdh_init{e = E}, - Ssh0 = #ssh{algorithms = #alg{kex=Kex}}) -> + Ssh0 = #ssh{algorithms = #alg{kex=Kex} = Algs}) -> %% server {G, P} = dh_group(Kex), if 1= - {Public, Private} = generate_key(dh, [P,G]), + Sz = dh_bits(Algs), + {Public, Private} = generate_key(dh, [P,G,2*Sz]), K = compute_key(dh, E, Private, [P,G]), MyPrivHostKey = get_host_key(Ssh0), MyPubHostKey = extract_public_key(MyPrivHostKey), @@ -426,12 +437,11 @@ handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request{min = Min0, {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]), + {ok, {_, {G,P}}} -> {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}}, + Ssh#ssh{keyex_key = {x, {G, P}}, keyex_info = {Min0, Max0, NBits} }}; {error,_} -> @@ -461,12 +471,11 @@ handle_kex_dh_gex_request(#ssh_msg_kex_dh_gex_request_old{n = 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]), + {ok, {_, {G,P}}} -> {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}}, + Ssh#ssh{keyex_key = {x, {G, P}}, keyex_info = {-1, -1, NBits} % flag for kex_h hash calc }}; {error,_} -> @@ -507,7 +516,8 @@ adjust_gex_min_max(Min0, Max0, Opts) -> handle_kex_dh_gex_group(#ssh_msg_kex_dh_gex_group{p = P, g = G}, Ssh0) -> %% client - {Public, Private} = generate_key(dh, [P,G]), + Sz = dh_bits(Ssh0#ssh.algorithms), + {Public, Private} = generate_key(dh, [P,G,2*Sz]), {SshPacket, Ssh1} = ssh_packet(#ssh_msg_kex_dh_gex_init{e = Public}, Ssh0), % Pub = G^Priv mod P (def) @@ -1117,6 +1127,51 @@ verify(PlainText, Hash, Sig, Key) -> %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%%% Unit: bytes + +-record(cipher_data, { + key_bytes, + iv_bytes, + block_bytes + }). + +%%% Start of a more parameterized crypto handling. +cipher('AEAD_AES_128_GCM') -> + #cipher_data{key_bytes = 16, + iv_bytes = 12, + block_bytes = 16}; + +cipher('AEAD_AES_256_GCM') -> + #cipher_data{key_bytes = 32, + iv_bytes = 12, + block_bytes = 16}; + +cipher('3des-cbc') -> + #cipher_data{key_bytes = 24, + iv_bytes = 8, + block_bytes = 8}; + +cipher('aes128-cbc') -> + #cipher_data{key_bytes = 16, + iv_bytes = 16, + block_bytes = 16}; + +cipher('aes128-ctr') -> + #cipher_data{key_bytes = 16, + iv_bytes = 16, + block_bytes = 16}; + +cipher('aes192-ctr') -> + #cipher_data{key_bytes = 24, + iv_bytes = 16, + block_bytes = 16}; + +cipher('aes256-ctr') -> + #cipher_data{key_bytes = 32, + iv_bytes = 16, + block_bytes = 16}. + + encrypt_init(#ssh{encrypt = none} = Ssh) -> {ok, Ssh}; encrypt_init(#ssh{encrypt = 'AEAD_AES_128_GCM', role = client} = Ssh) -> @@ -1497,11 +1552,11 @@ send_mac_init(SSH) -> common -> case SSH#ssh.role of client -> - KeySize = mac_key_size(SSH#ssh.send_mac), + KeySize = 8*mac_key_bytes(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), + KeySize = 8*mac_key_bytes(SSH#ssh.send_mac), Key = hash(SSH, "F", KeySize), {ok, SSH#ssh { send_mac_key = Key }} end; @@ -1520,10 +1575,10 @@ recv_mac_init(SSH) -> common -> case SSH#ssh.role of client -> - Key = hash(SSH, "F", mac_key_size(SSH#ssh.recv_mac)), + Key = hash(SSH, "F", 8*mac_key_bytes(SSH#ssh.recv_mac)), {ok, SSH#ssh { recv_mac_key = Key }}; server -> - Key = hash(SSH, "E", mac_key_size(SSH#ssh.recv_mac)), + Key = hash(SSH, "E", 8*mac_key_bytes(SSH#ssh.recv_mac)), {ok, SSH#ssh { recv_mac_key = Key }} end; aead -> @@ -1640,13 +1695,15 @@ sha(?'secp384r1') -> sha(secp384r1); sha(?'secp521r1') -> sha(secp521r1). -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('hmac-sha2-512')-> 512; -mac_key_size(none) -> 0. +mac_key_bytes('hmac-sha1') -> 20; +mac_key_bytes('hmac-sha1-96') -> 20; +mac_key_bytes('hmac-md5') -> 16; +mac_key_bytes('hmac-md5-96') -> 16; +mac_key_bytes('hmac-sha2-256')-> 32; +mac_key_bytes('hmac-sha2-512')-> 64; +mac_key_bytes('AEAD_AES_128_GCM') -> 0; +mac_key_bytes('AEAD_AES_256_GCM') -> 0; +mac_key_bytes(none) -> 0. mac_digest_size('hmac-sha1') -> 20; mac_digest_size('hmac-sha1-96') -> 12; @@ -1671,6 +1728,13 @@ dh_group('diffie-hellman-group1-sha1') -> ?dh_group1; dh_group('diffie-hellman-group14-sha1') -> ?dh_group14. %%%---------------------------------------------------------------- +parallell_gen_key(Ssh = #ssh{keyex_key = {x, {G, P}}, + algorithms = Algs}) -> + Sz = dh_bits(Algs), + {Public, Private} = generate_key(dh, [P,G,2*Sz]), + Ssh#ssh{keyex_key = {{Private, Public}, {G, P}}}. + + generate_key(Algorithm, Args) -> {Public,Private} = crypto:generate_key(Algorithm, Args), {crypto:bytes_to_integer(Public), crypto:bytes_to_integer(Private)}. @@ -1681,6 +1745,15 @@ compute_key(Algorithm, OthersPublic, MyPrivate, Args) -> crypto:bytes_to_integer(Shared). +dh_bits(#alg{encrypt = Encrypt, + send_mac = SendMac}) -> + C = cipher(Encrypt), + 8 * lists:max([C#cipher_data.key_bytes, + C#cipher_data.block_bytes, + C#cipher_data.iv_bytes, + mac_key_bytes(SendMac) + ]). + ecdh_curve('ecdh-sha2-nistp256') -> secp256r1; ecdh_curve('ecdh-sha2-nistp384') -> secp384r1; ecdh_curve('ecdh-sha2-nistp521') -> secp521r1. -- cgit v1.2.3