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authorHans Nilsson <[email protected]>2015-05-13 17:36:24 +0200
committerHans <[email protected]>2015-05-26 15:08:25 +0200
commite5715f37dcfd9c21103232e699390d9736180923 (patch)
treee4bc0721ef3d1ba9736642ae5fb2eab6135a4b6a
parente4b26deed9f99b04dae1195144d9cbdbd61be515 (diff)
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ssh: New option 'preferred_algorithms'
This option enables the user to define which algorithms that are to be used as well as their precedences in the negotiation between server and client.
-rw-r--r--lib/ssh/doc/src/ssh.xml100
-rw-r--r--lib/ssh/src/ssh.erl144
-rw-r--r--lib/ssh/src/ssh_auth.erl66
-rw-r--r--lib/ssh/src/ssh_auth.hrl2
-rw-r--r--lib/ssh/src/ssh_connection_handler.erl70
-rw-r--r--lib/ssh/src/ssh_transport.erl131
6 files changed, 352 insertions, 161 deletions
diff --git a/lib/ssh/doc/src/ssh.xml b/lib/ssh/doc/src/ssh.xml
index df13442fc6..3e7726c24d 100644
--- a/lib/ssh/doc/src/ssh.xml
+++ b/lib/ssh/doc/src/ssh.xml
@@ -35,13 +35,15 @@
<section>
<title>SSH</title>
-
+ <marker id="supported"/>
<list type="bulleted">
<item>For application dependencies see <seealso marker="SSH_app"> ssh(6)</seealso> </item>
<item>Supported SSH version is 2.0.</item>
+ <item>Supported public key algorithms: ssh-rsa and ssh-dss.</item>
<item>Supported MAC algorithms: hmac-sha2-256 and hmac-sha1.</item>
<item>Supported encryption algorithms: aes128-ctr, aes128-cb and 3des-cbc.</item>
<item>Supported key exchange algorithms: diffie-hellman-group1-sha1.</item>
+ <item>Supported compression algorithms: none, zlib, [email protected],</item>
<item>Supports unicode filenames if the emulator and the underlaying OS support it.
See section DESCRIPTION in the
<seealso marker="kernel:file">file</seealso> manual page in <c>kernel</c>
@@ -79,6 +81,18 @@
<seealso marker="ssh_channel">ssh_channel(3)</seealso></p></item>
<tag><c>channel_init_args() =</c></tag>
<item><p><c>list()</c></p></item>
+
+ <tag><c>algs_list() =</c></tag>
+ <item><p><c>list( alg_entry() )</c></p></item>
+
+ <tag><c>alg_entry() =</c></tag>
+ <item><p><c>{kex, simple_algs()} | {public_key, simple_algs()} | {cipher, double_algs()} | {mac, double_algs()} | {compression, double_algs()}</c></p></item>
+
+ <tag><c>simple_algs() =</c></tag>
+ <item><p><c>list( atom() )</c></p></item>
+
+ <tag><c>double_algs() =</c></tag>
+ <item><p><c>[{client2serverlist,simple_algs()},{server2client,simple_algs()}] | simple_algs()</c></p></item>
</taglist>
</section>
@@ -160,19 +174,57 @@
and <c>password</c>. However, those optins are not always desirable
to use from a security point of view.</p>
</item>
+
<tag><c><![CDATA[{public_key_alg, 'ssh-rsa' | 'ssh-dss'}]]></c></tag>
<item>
+ <note>
+ <p>This option is kept for compatibility. It is ignored if the <c>preferred_algorithms</c>
+ option is used. The equivalence of <c>{public_key_alg,'ssh-dss'}</c> is
+ <c>{preferred_algorithms, [{public_key,['ssh-dss','ssh-rsa']}]}</c>.</p>
+ </note>
<p>Sets the preferred public key algorithm to use for user
authentication. If the preferred algorithm fails,
the other algorithm is tried. The default is
to try <c><![CDATA['ssh-rsa']]></c> first.</p>
</item>
+
<tag><c><![CDATA[{pref_public_key_algs, list()}]]></c></tag>
<item>
+ <note>
+ <p>This option is kept for compatibility. It is ignored if the <c>preferred_algorithms</c>
+ option is used. The equivalence of <c>{pref_public_key_algs,['ssh-dss']}</c> is
+ <c>{preferred_algorithms, [{public_key,['ssh-dss']}]}</c>.</p>
+ </note>
<p>List of public key algorithms to try to use.
<c>'ssh-rsa'</c> and <c>'ssh-dss'</c> are available.
Overrides <c><![CDATA[{public_key_alg, 'ssh-rsa' | 'ssh-dss'}]]></c></p>
</item>
+
+ <tag><c><![CDATA[{preferred_algorithms, algs_list()}]]></c></tag>
+ <item>
+ <p>List of algorithms to use in the algorithm negotiation. The default <c>algs_list()</c> can
+ be obtained from <seealso marker="#default_algorithms/0">default_algorithms/0</seealso>.
+ </p>
+ <p>Here is an example of this option:</p>
+ <code>
+{preferred_algorithms,
+ [{public_key,['ssh-rsa','ssh-dss']},
+ {cipher,[{client2server,['aes128-ctr']},
+ {server2client,['aes128-cbc','3des-cbc']}]},
+ {mac,['hmac-sha2-256','hmac-sha1']},
+ {compression,[none,zlib]}
+}
+</code>
+ <p>Note that we want different algorithms in the two directions for <c>cipher</c>, but the same in
+ both directions for <c>mac</c> and <c>compression</c>. We keep the default for <c>kex</c> and
+ <c>public_key</c> but has given the default value explicitly for <c>public_key</c></p>
+ <warning>
+ <p>Changing the values can make a connection less secure. Do not change unless you
+ know exactly what you are doing. If you do not understand the values then you
+ are not supposed to change them</p>
+ </warning>
+ </item>
+
<tag><c><![CDATA[{connect_timeout, timeout()}]]></c></tag>
<item>
<p>Sets a time-out on the transport layer
@@ -341,6 +393,32 @@
user. From a security perspective this option makes
the server very vulnerable.</p>
</item>
+
+ <tag><c><![CDATA[{preferred_algorithms, algs_list()}]]></c></tag>
+ <item>
+ <p>List of algorithms to use in the algorithm negotiation. The default <c>algs_list()</c> can
+ be obtained from <seealso marker="#default_algorithms/0">default_algorithms/0</seealso>.
+ </p>
+ <p>Here is an example of this option:</p>
+ <code>
+{preferred_algorithms,
+ [{public_key,['ssh-rsa','ssh-dss']},
+ {cipher,[{client2server,['aes128-ctr']},
+ {server2client,['aes128-cbc','3des-cbc']}]},
+ {mac,['hmac-sha2-256','hmac-sha1']},
+ {compression,[none,zlib]}
+}
+</code>
+ <p>Note that we want different algorithms in the two directions for <c>cipher</c>, but the same in
+ both directions for <c>mac</c> and <c>compression</c>. We keep the default for <c>kex</c> and
+ <c>public_key</c> but has given the default value explicitly for <c>public_key</c></p>
+ <warning>
+ <p>Changing the values can make a connection less secure. Do not change unless you
+ know exactly what you are doing. If you do not understand the values then you
+ are not supposed to change them</p>
+ </warning>
+ </item>
+
<tag><c><![CDATA[{pwdfun, fun(User::string(), password::string()) -> boolean()}]]></c></tag>
<item>
<p>Provides a function for password validation. This function is called
@@ -445,6 +523,26 @@
</desc>
</func>
+ <func>
+ <name>default_algorithms() -> algs_list()</name>
+ <fsummary>Get a list declaring the supported algorithms</fsummary>
+ <desc>
+ <p>Returns a key-value list, where the keys are the different types of algorithms and the values are the
+ algorithms themselves. An example:</p>
+ <code>
+20> ssh:default_algorithms().
+[{kex,['diffie-hellman-group1-sha1']},
+ {public_key,['ssh-rsa','ssh-dss']},
+ {cipher,[{client2server,['aes128-ctr','aes128-cbc','3des-cbc']},
+ {server2client,['aes128-ctr','aes128-cbc','3des-cbc']}]},
+ {mac,[{client2server,['hmac-sha2-256','hmac-sha1']},
+ {server2client,['hmac-sha2-256','hmac-sha1']}]},
+ {compression,[{client2server,[none,zlib]},
+ {server2client,[none,zlib]}]}]
+21>
+</code>
+ </desc>
+ </func>
<func>
<name>shell(Host) -> </name>
diff --git a/lib/ssh/src/ssh.erl b/lib/ssh/src/ssh.erl
index a9d6f09e72..c3b0e3edc1 100644
--- a/lib/ssh/src/ssh.erl
+++ b/lib/ssh/src/ssh.erl
@@ -28,6 +28,7 @@
-export([start/0, start/1, stop/0, connect/3, connect/4, close/1, connection_info/2,
channel_info/3,
daemon/1, daemon/2, daemon/3,
+ default_algorithms/0,
stop_listener/1, stop_listener/2, stop_daemon/1, stop_daemon/2,
shell/1, shell/2, shell/3]).
@@ -208,6 +209,11 @@ shell(Host, Port, Options) ->
end.
%%--------------------------------------------------------------------
+%%--------------------------------------------------------------------
+default_algorithms() ->
+ ssh_transport:default_algorithms().
+
+%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
fix_idle_time(SshOptions) ->
@@ -259,7 +265,7 @@ do_start_daemon(Host, Port, Options, SocketOptions) ->
end.
handle_options(Opts) ->
- try handle_option(proplists:unfold(Opts), [], []) of
+ try handle_option(algs_compatibility(proplists:unfold(Opts)), [], []) of
{Inet, Ssh} ->
{handle_ip(Inet), Ssh}
catch
@@ -267,6 +273,35 @@ handle_options(Opts) ->
Error
end.
+
+algs_compatibility(Os) ->
+ %% Take care of old options 'public_key_alg' and 'pref_public_key_algs'
+ comp_pk(proplists:get_value(preferred_algorithms,Os),
+ proplists:get_value(pref_public_key_algs,Os),
+ proplists:get_value(public_key_alg, Os),
+ [{K,V} || {K,V} <- Os,
+ K =/= public_key_alg,
+ K =/= pref_public_key_algs]
+ ).
+
+comp_pk(undefined, undefined, undefined, Os) -> Os;
+comp_pk( PrefAlgs, _, _, Os) when PrefAlgs =/= undefined -> Os;
+
+comp_pk(undefined, undefined, ssh_dsa, Os) -> comp_pk(undefined, undefined, 'ssh-dss', Os);
+comp_pk(undefined, undefined, ssh_rsa, Os) -> comp_pk(undefined, undefined, 'ssh-rsa', Os);
+comp_pk(undefined, undefined, PK, Os) ->
+ PKs = [PK | ssh_transport:supported_algorithms(public_key)--[PK]],
+ [{preferred_algorithms, [{public_key,PKs}] } | Os];
+
+comp_pk(undefined, PrefPKs, _, Os) when PrefPKs =/= undefined ->
+ PKs = [case PK of
+ ssh_dsa -> 'ssh-dss';
+ ssh_rsa -> 'ssh-rsa';
+ _ -> PK
+ end || PK <- PrefPKs],
+ [{preferred_algorithms, [{public_key,PKs}]} | Os].
+
+
handle_option([], SocketOptions, SshOptions) ->
{SocketOptions, SshOptions};
handle_option([{system_dir, _} = Opt | Rest], SocketOptions, SshOptions) ->
@@ -279,8 +314,6 @@ handle_option([{silently_accept_hosts, _} = Opt | Rest], SocketOptions, SshOptio
handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
handle_option([{user_interaction, _} = Opt | Rest], SocketOptions, SshOptions) ->
handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
-handle_option([{public_key_alg, _} = Opt | Rest], SocketOptions, SshOptions) ->
- handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
handle_option([{connect_timeout, _} = Opt | Rest], SocketOptions, SshOptions) ->
handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
handle_option([{user, _} = Opt | Rest], SocketOptions, SshOptions) ->
@@ -329,7 +362,7 @@ handle_option([{exec, _} = Opt | Rest], SocketOptions, SshOptions) ->
handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
handle_option([{auth_methods, _} = Opt | Rest], SocketOptions, SshOptions) ->
handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
-handle_option([{pref_public_key_algs, _} = Opt | Rest], SocketOptions, SshOptions) ->
+handle_option([{preferred_algorithms,_} = Opt | Rest], SocketOptions, SshOptions) ->
handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
handle_option([{quiet_mode, _} = Opt|Rest], SocketOptions, SshOptions) ->
handle_option(Rest, SocketOptions, [handle_ssh_option(Opt) | SshOptions]);
@@ -365,19 +398,8 @@ handle_ssh_option({silently_accept_hosts, Value} = Opt) when is_boolean(Value) -
Opt;
handle_ssh_option({user_interaction, Value} = Opt) when is_boolean(Value) ->
Opt;
-handle_ssh_option({public_key_alg, ssh_dsa}) ->
- {public_key_alg, 'ssh-dss'};
-handle_ssh_option({public_key_alg, ssh_rsa}) ->
- {public_key_alg, 'ssh-rsa'};
-handle_ssh_option({public_key_alg, Value} = Opt) when Value == 'ssh-rsa'; Value == 'ssh-dss' ->
- Opt;
-handle_ssh_option({pref_public_key_algs, Value} = Opt) when is_list(Value), length(Value) >= 1 ->
- case handle_pref_algs(Value, []) of
- {true, NewOpts} ->
- NewOpts;
- _ ->
- throw({error, {eoptions, Opt}})
- end;
+handle_ssh_option({preferred_algorithms,[_|_]} = Opt) ->
+ handle_pref_algs(Opt);
handle_ssh_option({connect_timeout, Value} = Opt) when is_integer(Value); Value == infinity ->
Opt;
handle_ssh_option({max_sessions, Value} = Opt) when is_integer(Value), Value>0 ->
@@ -463,23 +485,83 @@ handle_inet_option({reuseaddr, _} = Opt) ->
%% Option verified by inet
handle_inet_option(Opt) ->
Opt.
+
+
%% Check preferred algs
-handle_pref_algs([], Acc) ->
- {true, lists:reverse(Acc)};
-handle_pref_algs([H|T], Acc) ->
- case H of
- ssh_dsa ->
- handle_pref_algs(T, ['ssh-dss'| Acc]);
- ssh_rsa ->
- handle_pref_algs(T, ['ssh-rsa'| Acc]);
- 'ssh-dss' ->
- handle_pref_algs(T, ['ssh-dss'| Acc]);
- 'ssh-rsa' ->
- handle_pref_algs(T, ['ssh-rsa'| Acc]);
- _ ->
- false
+
+handle_pref_algs({preferred_algorithms,Algs}) ->
+ try alg_duplicates(Algs, [], []) of
+ [] ->
+ {preferred_algorithms,
+ [try ssh_transport:supported_algorithms(Key)
+ of
+ DefAlgs -> handle_pref_alg(Key,Vals,DefAlgs)
+ catch
+ _:_ -> throw({error, {{eoptions, {preferred_algorithms,Key}},
+ "Bad preferred_algorithms key"}})
+ end || {Key,Vals} <- Algs]
+ };
+
+ Dups ->
+ throw({error, {{eoptions, {preferred_algorithms,Dups}}, "Duplicates found"}})
+ catch
+ _:_ ->
+ throw({error, {{eoptions, preferred_algorithms}, "Malformed"}})
end.
+alg_duplicates([{K,V}|KVs], Ks, Dups0) ->
+ Dups =
+ case lists:member(K,Ks) of
+ true ->
+ [K|Dups0];
+ false ->
+ Dups0
+ end,
+ case V--lists:usort(V) of
+ [] ->
+ alg_duplicates(KVs, [K|Ks], Dups);
+ Ds ->
+ alg_duplicates(KVs, [K|Ks], Dups++Ds)
+ end;
+alg_duplicates([], _Ks, Dups) ->
+ Dups.
+
+handle_pref_alg(Key,
+ Vs=[{client2server,C2Ss=[_|_]},{server2client,S2Cs=[_|_]}],
+ [{client2server,Sup_C2Ss},{server2client,Sup_S2Cs}]
+ ) ->
+ chk_alg_vs(Key, C2Ss, Sup_C2Ss),
+ chk_alg_vs(Key, S2Cs, Sup_S2Cs),
+ {Key, Vs};
+
+handle_pref_alg(Key,
+ Vs=[{server2client,[_|_]},{client2server,[_|_]}],
+ Sup=[{client2server,_},{server2client,_}]
+ ) ->
+ handle_pref_alg(Key, lists:reverse(Vs), Sup);
+
+handle_pref_alg(Key,
+ Vs=[V|_],
+ Sup=[{client2server,_},{server2client,_}]
+ ) when is_atom(V) ->
+ handle_pref_alg(Key, [{client2server,Vs},{server2client,Vs}], Sup);
+
+handle_pref_alg(Key,
+ Vs=[V|_],
+ Sup=[S|_]
+ ) when is_atom(V), is_atom(S) ->
+ chk_alg_vs(Key, Vs, Sup),
+ {Key, Vs};
+
+handle_pref_alg(Key, Vs, _) ->
+ throw({error, {{eoptions, {preferred_algorithms,[{Key,Vs}]}}, "Badly formed list"}}).
+
+chk_alg_vs(OptKey, Values, SupportedValues) ->
+ case (Values -- SupportedValues) of
+ [] -> Values;
+ Bad -> throw({error, {{eoptions, {OptKey,Bad}}, "Unsupported value(s) found"}})
+ end.
+
handle_ip(Inet) -> %% Default to ipv4
case lists:member(inet, Inet) of
true ->
diff --git a/lib/ssh/src/ssh_auth.erl b/lib/ssh/src/ssh_auth.erl
index 45c4d52d7e..197808754c 100644
--- a/lib/ssh/src/ssh_auth.erl
+++ b/lib/ssh/src/ssh_auth.erl
@@ -30,7 +30,8 @@
-export([publickey_msg/1, password_msg/1, keyboard_interactive_msg/1,
service_request_msg/1, init_userauth_request_msg/1,
userauth_request_msg/1, handle_userauth_request/3,
- handle_userauth_info_request/3, handle_userauth_info_response/2
+ handle_userauth_info_request/3, handle_userauth_info_response/2,
+ default_public_key_algorithms/0
]).
%%--------------------------------------------------------------------
@@ -115,33 +116,16 @@ init_userauth_request_msg(#ssh{opts = Opts} = Ssh) ->
service = "ssh-connection",
method = "none",
data = <<>>},
- case proplists:get_value(pref_public_key_algs, Opts, false) of
- false ->
- FirstAlg = proplists:get_value(public_key_alg, Opts, ?PREFERRED_PK_ALG),
- SecondAlg = other_alg(FirstAlg),
- Prefs = method_preference(FirstAlg, SecondAlg),
- ssh_transport:ssh_packet(Msg, Ssh#ssh{user = User,
- userauth_preference = Prefs,
- userauth_methods = none,
- service = "ssh-connection"});
- Algs ->
- FirstAlg = lists:nth(1, Algs),
- case length(Algs) =:= 2 of
- true ->
- SecondAlg = other_alg(FirstAlg),
- Prefs = method_preference(FirstAlg, SecondAlg),
- ssh_transport:ssh_packet(Msg, Ssh#ssh{user = User,
- userauth_preference = Prefs,
- userauth_methods = none,
- service = "ssh-connection"});
- _ ->
- Prefs = method_preference(FirstAlg),
- ssh_transport:ssh_packet(Msg, Ssh#ssh{user = User,
- userauth_preference = Prefs,
- userauth_methods = none,
- service = "ssh-connection"})
- end
- end;
+
+
+ Algs = proplists:get_value(public_key,
+ proplists:get_value(preferred_algorithms, Opts, []),
+ default_public_key_algorithms()),
+ Prefs = method_preference(Algs),
+ ssh_transport:ssh_packet(Msg, Ssh#ssh{user = User,
+ userauth_preference = Prefs,
+ userauth_methods = none,
+ service = "ssh-connection"});
{error, no_user} ->
ErrStr = "Could not determine the users name",
throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_ILLEGAL_USER_NAME,
@@ -287,20 +271,20 @@ handle_userauth_info_response(#ssh_msg_userauth_info_response{},
"keyboard-interactive",
language = "en"}).
+
+default_public_key_algorithms() -> ?PREFERRED_PK_ALGS.
+
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
-method_preference(Alg1, Alg2) ->
- [{"publickey", ?MODULE, publickey_msg, [Alg1]},
- {"publickey", ?MODULE, publickey_msg,[Alg2]},
- {"password", ?MODULE, password_msg, []},
- {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []}
- ].
-method_preference(Alg1) ->
- [{"publickey", ?MODULE, publickey_msg, [Alg1]},
- {"password", ?MODULE, password_msg, []},
- {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []}
- ].
+method_preference(Algs) ->
+ lists:foldr(fun(A, Acc) ->
+ [{"publickey", ?MODULE, publickey_msg, [A]} | Acc]
+ end,
+ [{"password", ?MODULE, password_msg, []},
+ {"keyboard-interactive", ?MODULE, keyboard_interactive_msg, []}
+ ],
+ Algs).
user_name(Opts) ->
Env = case os:type() of
@@ -418,10 +402,6 @@ keyboard_interact_fun(KbdInteractFun, Name, Instr, PromptInfos, NumPrompts) ->
language = "en"}})
end.
-other_alg('ssh-rsa') ->
- 'ssh-dss';
-other_alg('ssh-dss') ->
- 'ssh-rsa'.
decode_public_key_v2(<<?UINT32(Len0), _:Len0/binary,
?UINT32(Len1), BinE:Len1/binary,
?UINT32(Len2), BinN:Len2/binary>>
diff --git a/lib/ssh/src/ssh_auth.hrl b/lib/ssh/src/ssh_auth.hrl
index 6cd8e6bf14..764c9f4246 100644
--- a/lib/ssh/src/ssh_auth.hrl
+++ b/lib/ssh/src/ssh_auth.hrl
@@ -23,7 +23,7 @@
-define(SUPPORTED_AUTH_METHODS, "publickey,keyboard-interactive,password").
--define(PREFERRED_PK_ALG, 'ssh-rsa').
+-define(PREFERRED_PK_ALGS, ['ssh-rsa','ssh-dss']).
-define(SSH_MSG_USERAUTH_REQUEST, 50).
-define(SSH_MSG_USERAUTH_FAILURE, 51).
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index 65208ae158..ca63d2194f 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -33,7 +33,7 @@
-include("ssh_transport.hrl").
-include("ssh_auth.hrl").
-include("ssh_connect.hrl").
-
+-compile(export_all).
-export([start_link/3]).
%% Internal application API
@@ -1156,54 +1156,38 @@ init_ssh(server = Role, Vsn, Version, Options, Socket) ->
supported_host_keys(client, _, Options) ->
try
- case extract_algs(proplists:get_value(pref_public_key_algs, Options, false), []) of
- false ->
- ["ssh-rsa", "ssh-dss"];
- Algs ->
- Algs
+ case proplists:get_value(public_key,
+ proplists:get_value(preferred_algorithms,Options,[])
+ ) of
+ undefined ->
+ ssh_auth:default_public_key_algorithms();
+ L ->
+ L -- (L--ssh_auth:default_public_key_algorithms())
end
+ of
+ [] ->
+ {stop, {shutdown, "No public key algs"}};
+ Algs ->
+ [atom_to_list(A) || A<-Algs]
catch
exit:Reason ->
{stop, {shutdown, Reason}}
end;
supported_host_keys(server, KeyCb, Options) ->
- lists:foldl(fun(Type, Acc) ->
- case available_host_key(KeyCb, Type, Options) of
- {error, _} ->
- Acc;
- Alg ->
- [Alg | Acc]
- end
- end, [],
- %% Prefered alg last so no need to reverse
- ["ssh-dss", "ssh-rsa"]).
-extract_algs(false, _) ->
- false;
-extract_algs([],[]) ->
- false;
-extract_algs([], NewList) ->
- lists:reverse(NewList);
-extract_algs([H|T], NewList) ->
- case H of
- 'ssh-dss' ->
- extract_algs(T, ["ssh-dss"|NewList]);
- 'ssh-rsa' ->
- extract_algs(T, ["ssh-rsa"|NewList])
- end.
-available_host_key(KeyCb, "ssh-dss"= Alg, Opts) ->
- case KeyCb:host_key('ssh-dss', Opts) of
- {ok, _} ->
- Alg;
- Other ->
- Other
- end;
-available_host_key(KeyCb, "ssh-rsa" = Alg, Opts) ->
- case KeyCb:host_key('ssh-rsa', Opts) of
- {ok, _} ->
- Alg;
- Other ->
- Other
- end.
+ Algs=
+ [atom_to_list(A) || A <- proplists:get_value(public_key,
+ proplists:get_value(preferred_algorithms,Options,[]),
+ ssh_auth:default_public_key_algorithms()
+ ),
+ available_host_key(KeyCb, A, Options)
+ ],
+ Algs.
+
+
+%% Alg :: atom()
+available_host_key(KeyCb, Alg, Opts) ->
+ element(1, catch KeyCb:host_key(Alg, Opts)) == ok.
+
send_msg(Msg, #state{socket = Socket, transport_cb = Transport}) ->
Transport:send(Socket, Msg).
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index d6414bab6c..95840c94ad 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -31,6 +31,8 @@
-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,
@@ -42,6 +44,68 @@
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 '[email protected]' because there seem to be problems
+ supported_algorithms(compression, same(['[email protected]']));
+default_algorithms(Alg) ->
+ supported_algorithms(Alg).
+
+
+supported_algorithms() -> [{K,supported_algorithms(K)} || K <- algo_classes()].
+
+supported_algorithms(kex) ->
+ ['diffie-hellman-group1-sha1'];
+supported_algorithms(public_key) ->
+ ssh_auth:default_public_key_algorithms();
+supported_algorithms(cipher) ->
+ Supports = crypto:supports(),
+ CipherAlgos = [{aes_ctr, 'aes128-ctr'}, {aes_cbc128, 'aes128-cbc'}, {des3_cbc, '3des-cbc'}],
+ Algs = [SshAlgo ||
+ {CryptoAlgo, SshAlgo} <- CipherAlgos,
+ lists:member(CryptoAlgo, proplists:get_value(ciphers, Supports, []))],
+ same(Algs);
+supported_algorithms(mac) ->
+ Supports = crypto:supports(),
+ HashAlgos = [{sha256, 'hmac-sha2-256'}, {sha, 'hmac-sha1'}],
+ Algs = [SshAlgo ||
+ {CryptoAlgo, SshAlgo} <- HashAlgos,
+ lists:member(CryptoAlgo, proplists:get_value(hashs, Supports, []))],
+ same(Algs);
+supported_algorithms(compression) ->
+ same(['none','zlib','[email protected]']).
+
+
+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.
+
+
+
+
+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))};
@@ -128,62 +192,45 @@ key_exchange_init_msg(Ssh0) ->
kex_init(#ssh{role = Role, opts = Opts, available_host_keys = HostKeyAlgs}) ->
Random = ssh_bits:random(16),
- Compression = case proplists:get_value(compression, Opts, none) of
- openssh_zlib -> ["[email protected]", "none"];
- zlib -> ["zlib", "none"];
- none -> ["none", "zlib"]
- end,
- kexinit_messsage(Role, Random, Compression, HostKeyAlgs).
+ 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}.
-available_ssh_algos() ->
- Supports = crypto:supports(),
- CipherAlgos = [{aes_ctr, "aes128-ctr"}, {aes_cbc128, "aes128-cbc"}, {des3_cbc, "3des-cbc"}],
- Ciphers = [SshAlgo ||
- {CryptoAlgo, SshAlgo} <- CipherAlgos,
- lists:member(CryptoAlgo, proplists:get_value(ciphers, Supports, []))],
- HashAlgos = [{sha256, "hmac-sha2-256"}, {sha, "hmac-sha1"}],
- Hashs = [SshAlgo ||
- {CryptoAlgo, SshAlgo} <- HashAlgos,
- lists:member(CryptoAlgo, proplists:get_value(hashs, Supports, []))],
- {Ciphers, Hashs}.
-
-kexinit_messsage(client, Random, Compression, HostKeyAlgs) ->
- {CipherAlgs, HashAlgs} = available_ssh_algos(),
- #ssh_msg_kexinit{
- cookie = Random,
- kex_algorithms = ["diffie-hellman-group1-sha1"],
- server_host_key_algorithms = HostKeyAlgs,
- encryption_algorithms_client_to_server = CipherAlgs,
- encryption_algorithms_server_to_client = CipherAlgs,
- mac_algorithms_client_to_server = HashAlgs,
- mac_algorithms_server_to_client = HashAlgs,
- compression_algorithms_client_to_server = Compression,
- compression_algorithms_server_to_client = Compression,
- languages_client_to_server = [],
- languages_server_to_client = []
- };
-kexinit_messsage(server, Random, Compression, HostKeyAlgs) ->
- {CipherAlgs, HashAlgs} = available_ssh_algos(),
+kexinit_message(_Role, Random, Algs, HostKeyAlgs) ->
#ssh_msg_kexinit{
cookie = Random,
- kex_algorithms = ["diffie-hellman-group1-sha1"],
+ kex_algorithms = to_strings( get_algs(kex,Algs) ),
server_host_key_algorithms = HostKeyAlgs,
- encryption_algorithms_client_to_server = CipherAlgs,
- encryption_algorithms_server_to_client = CipherAlgs,
- mac_algorithms_client_to_server = HashAlgs,
- mac_algorithms_server_to_client = HashAlgs,
- compression_algorithms_client_to_server = Compression,
- compression_algorithms_server_to_client = Compression,
+ 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),