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authorHans Nilsson <[email protected]>2017-01-26 22:48:13 +0100
committerHans Nilsson <[email protected]>2017-01-30 10:13:58 +0100
commit80a162cdf59f6a3826fba0cc0d3b861451a6b102 (patch)
tree64de1bb4302a4cc349eb4925f88764d69737606f /lib/ssh/src/ssh_transport.erl
parent6468551301f906ce4199ef69b677147d88d64242 (diff)
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ssh: optimize kex dh_gex using new crypto functionality
Diffstat (limited to 'lib/ssh/src/ssh_transport.erl')
-rw-r--r--lib/ssh/src/ssh_transport.erl123
1 files changed, 98 insertions, 25 deletions
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=<E, E=<(P-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.