diff options
Diffstat (limited to 'lib/ssh')
| -rw-r--r-- | lib/ssh/doc/src/ssh.xml | 100 | ||||
| -rw-r--r-- | lib/ssh/src/ssh.erl | 144 | ||||
| -rw-r--r-- | lib/ssh/src/ssh_auth.erl | 66 | ||||
| -rw-r--r-- | lib/ssh/src/ssh_auth.hrl | 2 | ||||
| -rw-r--r-- | lib/ssh/src/ssh_connection_handler.erl | 70 | ||||
| -rw-r--r-- | lib/ssh/src/ssh_transport.erl | 131 |
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), |