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-rw-r--r--lib/ssh/src/ssh_transport.erl221
1 files changed, 147 insertions, 74 deletions
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index 6b47868d5c..d623d24529 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -38,6 +38,7 @@
handle_hello_version/1,
key_exchange_init_msg/1,
key_init/3, new_keys_message/1,
+ ext_info_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,
@@ -230,7 +231,7 @@ key_exchange_init_msg(Ssh0) ->
kex_init(#ssh{role = Role, opts = Opts, available_host_keys = HostKeyAlgs}) ->
Random = ssh_bits:random(16),
PrefAlgs = ?GET_OPT(preferred_algorithms, Opts),
- kexinit_message(Role, Random, PrefAlgs, HostKeyAlgs).
+ kexinit_message(Role, Random, PrefAlgs, HostKeyAlgs, Opts).
key_init(client, Ssh, Value) ->
Ssh#ssh{c_keyinit = Value};
@@ -238,10 +239,11 @@ key_init(server, Ssh, Value) ->
Ssh#ssh{s_keyinit = Value}.
-kexinit_message(_Role, Random, Algs, HostKeyAlgs) ->
+kexinit_message(Role, Random, Algs, HostKeyAlgs, Opts) ->
#ssh_msg_kexinit{
cookie = Random,
- kex_algorithms = to_strings( get_algs(kex,Algs) ),
+ kex_algorithms = to_strings( get_algs(kex,Algs) )
+ ++ kex_ext_info(Role,Opts),
server_host_key_algorithms = HostKeyAlgs,
encryption_algorithms_client_to_server = c2s(cipher,Algs),
encryption_algorithms_server_to_client = s2c(cipher,Algs),
@@ -263,39 +265,42 @@ 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),
+ {SshPacket, Ssh1} = ssh_packet(#ssh_msg_newkeys{}, Ssh0),
+ Ssh = install_alg(snd, Ssh1),
{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});
- {false,Alg} ->
- %% TODO: Correct code?
- ssh_connection_handler:disconnect(
- #ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
- description = "Selection of key exchange algorithm failed: "
- ++ Alg
- })
+ #ssh{role = client} = Ssh) ->
+ try
+ {ok, Algorithms} = select_algorithm(client, Own, CounterPart, Ssh#ssh.opts),
+ true = verify_algorithm(Algorithms),
+ Algorithms
+ of
+ Algos ->
+ key_exchange_first_msg(Algos#alg.kex,
+ Ssh#ssh{algorithms = Algos})
+ catch
+ _:_ ->
+ ssh_connection_handler:disconnect(
+ #ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
+ description = "Selection of key exchange algorithm failed"})
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}};
- {false,Alg} ->
- ssh_connection_handler:disconnect(
- #ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
- description = "Selection of key exchange algorithm failed: "
- ++ Alg
- })
+ #ssh{role = server} = Ssh) ->
+ try
+ {ok, Algorithms} = select_algorithm(server, CounterPart, Own, Ssh#ssh.opts),
+ true = verify_algorithm(Algorithms),
+ Algorithms
+ of
+ Algos ->
+ {ok, Ssh#ssh{algorithms = Algos}}
+ catch
+ _:_ ->
+ ssh_connection_handler:disconnect(
+ #ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
+ description = "Selection of key exchange algorithm failed"})
end.
@@ -308,6 +313,8 @@ verify_algorithm(#alg{decrypt = undefined}) -> {false, "decrypt"};
verify_algorithm(#alg{compress = undefined}) -> {false, "compress"};
verify_algorithm(#alg{decompress = undefined}) -> {false, "decompress"};
verify_algorithm(#alg{kex = Kex}) ->
+ %% This also catches the error if 'ext-info-s' or 'ext-info-c' is selected.
+ %% (draft-ietf-curdle-ssh-ext-info-04 2.2)
case lists:member(Kex, supported_algorithms(kex)) of
true -> true;
false -> {false, "kex"}
@@ -414,9 +421,9 @@ handle_kexdh_reply(#ssh_msg_kexdh_reply{public_host_key = PeerPubHostKey,
case verify_host_key(Ssh0, PeerPubHostKey, H, H_SIG) of
ok ->
{SshPacket, Ssh} = ssh_packet(#ssh_msg_newkeys{}, Ssh0),
- {ok, SshPacket, Ssh#ssh{shared_secret = ssh_bits:mpint(K),
- exchanged_hash = H,
- session_id = sid(Ssh, H)}};
+ {ok, SshPacket, install_alg(snd, Ssh#ssh{shared_secret = ssh_bits:mpint(K),
+ exchanged_hash = H,
+ session_id = sid(Ssh, H)})};
Error ->
ssh_connection_handler:disconnect(
#ssh_msg_disconnect{
@@ -584,9 +591,9 @@ handle_kex_dh_gex_reply(#ssh_msg_kex_dh_gex_reply{public_host_key = PeerPubHostK
case verify_host_key(Ssh0, PeerPubHostKey, H, H_SIG) of
ok ->
{SshPacket, Ssh} = ssh_packet(#ssh_msg_newkeys{}, Ssh0),
- {ok, SshPacket, Ssh#ssh{shared_secret = ssh_bits:mpint(K),
- exchanged_hash = H,
- session_id = sid(Ssh, H)}};
+ {ok, SshPacket, install_alg(snd, Ssh#ssh{shared_secret = ssh_bits:mpint(K),
+ exchanged_hash = H,
+ session_id = sid(Ssh, H)})};
_Error ->
ssh_connection_handler:disconnect(
#ssh_msg_disconnect{
@@ -660,9 +667,9 @@ handle_kex_ecdh_reply(#ssh_msg_kex_ecdh_reply{public_host_key = PeerPubHostKey,
case verify_host_key(Ssh0, PeerPubHostKey, H, H_SIG) of
ok ->
{SshPacket, Ssh} = ssh_packet(#ssh_msg_newkeys{}, Ssh0),
- {ok, SshPacket, Ssh#ssh{shared_secret = ssh_bits:mpint(K),
- exchanged_hash = H,
- session_id = sid(Ssh, H)}};
+ {ok, SshPacket, install_alg(snd, Ssh#ssh{shared_secret = ssh_bits:mpint(K),
+ exchanged_hash = H,
+ session_id = sid(Ssh, H)})};
Error ->
ssh_connection_handler:disconnect(
#ssh_msg_disconnect{
@@ -682,7 +689,7 @@ handle_kex_ecdh_reply(#ssh_msg_kex_ecdh_reply{public_host_key = PeerPubHostKey,
%%%----------------------------------------------------------------
handle_new_keys(#ssh_msg_newkeys{}, Ssh0) ->
- try install_alg(Ssh0) of
+ try install_alg(rcv, Ssh0) of
#ssh{} = Ssh ->
{ok, Ssh}
catch
@@ -693,6 +700,34 @@ handle_new_keys(#ssh_msg_newkeys{}, Ssh0) ->
})
end.
+
+%%%----------------------------------------------------------------
+kex_ext_info(Role, Opts) ->
+ case ?GET_OPT(recv_ext_info,Opts) of
+ true when Role==client -> ["ext-info-c"];
+ true when Role==server -> ["ext-info-s"];
+ false -> []
+ end.
+
+ext_info_message(#ssh{role=client,
+ algorithms=#alg{send_ext_info=true}} = Ssh0) ->
+ %% FIXME: no extensions implemented for clients
+ {ok, "", Ssh0};
+
+ext_info_message(#ssh{role=server,
+ algorithms=#alg{send_ext_info=true}} = Ssh0) ->
+ AlgsList = lists:map(fun erlang:atom_to_list/1,
+ ssh_transport:default_algorithms(public_key)),
+ Msg = #ssh_msg_ext_info{nr_extensions = 1,
+ data = [{"server-sig-algs", string:join(AlgsList,",")}]
+ },
+ {SshPacket, Ssh} = ssh_packet(Msg, Ssh0),
+ {ok, SshPacket, Ssh};
+
+ext_info_message(Ssh0) ->
+ {ok, "", Ssh0}. % "" means: 'do not send'
+
+%%%----------------------------------------------------------------
%% select session id
sid(#ssh{session_id = undefined}, H) ->
H;
@@ -812,7 +847,7 @@ known_host_key(#ssh{opts = Opts, key_cb = {KeyCb,KeyCbOpts}, peer = {PeerName,_}
%%
%% 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) ->
+select_algorithm(Role, Client, Server, Opts) ->
{Encrypt0, Decrypt0} = select_encrypt_decrypt(Role, Client, Server),
{SendMac0, RecvMac0} = select_send_recv_mac(Role, Client, Server),
@@ -837,17 +872,34 @@ select_algorithm(Role, Client, Server) ->
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}.
+ SendExtInfo =
+ %% To send we must have that option enabled and ...
+ ?GET_OPT(send_ext_info,Opts) andalso
+ %% ... the peer must have told us to send:
+ case Role of
+ server -> lists:member("ext-info-c", Client#ssh_msg_kexinit.kex_algorithms);
+ client -> lists:member("ext-info-s", Server#ssh_msg_kexinit.kex_algorithms)
+ end,
+
+ RecvExtInfo =
+ %% The peer should not send unless told so by us (which is
+ %% guided by an option).
+ %% (However a malicious peer could send anyway, so we must be prepared)
+ ?GET_OPT(recv_ext_info,Opts),
+
+ {ok, #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,
+ send_ext_info = SendExtInfo,
+ recv_ext_info = RecvExtInfo
+ }}.
%%% It is an agreed problem with RFC 5674 that if the selection is
@@ -928,45 +980,66 @@ select_compression_decompression(server, Client, Server) ->
Server#ssh_msg_kexinit.compression_algorithms_server_to_client),
{Compression, Decompression}.
-install_alg(SSH) ->
- SSH1 = alg_final(SSH),
- SSH2 = alg_setup(SSH1),
- alg_init(SSH2).
+%% DIr = rcv | snd
+install_alg(Dir, SSH) ->
+ SSH1 = alg_final(Dir, SSH),
+ SSH2 = alg_setup(Dir, SSH1),
+ alg_init(Dir, SSH2).
-alg_setup(SSH) ->
+alg_setup(snd, 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),
+ compress = ALG#alg.compress,
+ c_lng = ALG#alg.c_lng,
+ s_lng = ALG#alg.s_lng,
+ send_ext_info = ALG#alg.send_ext_info,
+ recv_ext_info = ALG#alg.recv_ext_info
+ };
+
+alg_setup(rcv, SSH) ->
+ ALG = SSH#ssh.algorithms,
+ SSH#ssh{kex = ALG#alg.kex,
+ hkey = ALG#alg.hkey,
+ decrypt = ALG#alg.decrypt,
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
+ send_ext_info = ALG#alg.send_ext_info,
+ recv_ext_info = ALG#alg.recv_ext_info
}.
-alg_init(SSH0) ->
+
+alg_init(snd, 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,SSH2} = encrypt_init(SSH1),
+ {ok,SSH3} = compress_init(SSH2),
+ SSH3;
+
+alg_init(rcv, SSH0) ->
+ {ok,SSH1} = recv_mac_init(SSH0),
+ {ok,SSH2} = decrypt_init(SSH1),
+ {ok,SSH3} = decompress_init(SSH2),
+ SSH3.
+
+
+alg_final(snd, 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.
+ {ok,SSH2} = encrypt_final(SSH1),
+ {ok,SSH3} = compress_final(SSH2),
+ SSH3;
+
+alg_final(rcv, SSH0) ->
+ {ok,SSH1} = recv_mac_final(SSH0),
+ {ok,SSH2} = decrypt_final(SSH1),
+ {ok,SSH3} = decompress_final(SSH2),
+ SSH3.
+
select_all(CL, SL) when length(CL) + length(SL) < ?MAX_NUM_ALGORITHMS ->
A = CL -- SL, %% algortihms only used by client
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-17 17:43:05 +0000