Ssh daemon handles RSA host keys

Solves OTP-7677

4 files changed, 56 insertions, 19 deletions

diff --git a/lib/ssh/src/ssh.hrl b/lib/ssh/src/ssh.hrl
index 7cebec1c74..da5750b6c3 100644
--- a/lib/ssh/src/ssh.hrl
+++ b/lib/ssh/src/ssh.hrl
@@ -126,7 +126,8 @@
 	  userauth_quiet_mode,              %  boolean()
 	  userauth_supported_methods , %  
 	  userauth_methods,
-	  userauth_preference	  
+	  userauth_preference,
+	  available_host_keys
 	 }).
 
 -record(alg,
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index 00b30e5434..a9bf23953d 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2008-2011. All Rights Reserved.
+%% Copyright Ericsson AB 2008-2012. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -637,16 +637,18 @@ init_ssh(client = Role, Vsn, Version, Options, Socket) ->
     {ok, PeerAddr} = inet:peername(Socket),
     
     PeerName =  proplists:get_value(host, Options),
+    KeyCb =  proplists:get_value(key_cb, Options, ssh_file),
 
     #ssh{role = Role,
 	 c_vsn = Vsn,
 	 c_version = Version,
-	 key_cb = proplists:get_value(key_cb, Options, ssh_file),
+	 key_cb = KeyCb,
 	 io_cb = IOCb,
 	 userauth_quiet_mode = proplists:get_value(quiet_mode, Options, false),
 	 opts = Options,
 	 userauth_supported_methods = AuthMethods,
-	 peer = {PeerName, PeerAddr}
+	 peer = {PeerName, PeerAddr},
+	 available_host_keys = supported_host_keys(Role, KeyCb, Options)
 	};
 
 init_ssh(server = Role, Vsn, Version, Options, Socket) ->
@@ -654,17 +656,50 @@ init_ssh(server = Role, Vsn, Version, Options, Socket) ->
     AuthMethods = proplists:get_value(auth_methods, Options, 
 				      ?SUPPORTED_AUTH_METHODS),
     {ok, PeerAddr} = inet:peername(Socket),
-    
+    KeyCb =  proplists:get_value(key_cb, Options, ssh_file),
+
     #ssh{role = Role,
 	 s_vsn = Vsn,
 	 s_version = Version,
-	 key_cb = proplists:get_value(key_cb, Options, ssh_file),
+	 key_cb = KeyCb,
 	 io_cb = proplists:get_value(io_cb, Options, ssh_io),
 	 opts = Options,
 	 userauth_supported_methods = AuthMethods,
-	 peer = {undefined, PeerAddr}
+	 peer = {undefined, PeerAddr},
+	 available_host_keys = supported_host_keys(Role, KeyCb, Options)
 	 }.
 
+supported_host_keys(client, _, _) ->
+    ["ssh-rsa", "ssh-dss"];
+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"]).
+
+available_host_key(KeyCb, "ssh-dss"= Alg, Opts) ->
+    Scope = proplists:get_value(key_scope, Opts, system),
+    case KeyCb:private_host_dsa_key(Scope, Opts) of
+	{ok, _} ->
+	    Alg;
+	Other ->
+	    Other
+    end;
+available_host_key(KeyCb, "ssh-rsa" = Alg, Opts) ->
+    Scope = proplists:get_value(key_scope, Opts, system),
+    case KeyCb:private_host_rsa_key(Scope, Opts) of
+	{ok, _} ->
+	    Alg;
+	Other ->
+	    Other
+    end.
+
 send_msg(Msg, #state{socket = Socket, transport_cb = Transport}) ->
     Transport:send(Socket, Msg).
 
diff --git a/lib/ssh/src/ssh_file.erl b/lib/ssh/src/ssh_file.erl
index 49106ccdb3..d5cacc3294 100644
--- a/lib/ssh/src/ssh_file.erl
+++ b/lib/ssh/src/ssh_file.erl
@@ -30,7 +30,8 @@
 
 -export([public_host_dsa_key/2,private_host_dsa_key/2,
 	 public_host_rsa_key/2,private_host_rsa_key/2,
-	 public_host_key/2,private_host_key/2,
+	 %%public_host_key/2,
+	 private_host_key/2,
 	 lookup_host_key/3, add_host_key/3,
 	 lookup_user_key/4, ssh_dir/2, file_name/3]).
 
@@ -62,9 +63,9 @@ private_host_rsa_key(Type, Opts) ->
     Password = proplists:get_value(password, Opts, ignore),
     decode(File, Password).
 
-public_host_key(Type, Opts) ->
-    File = file_name(Type, "ssh_host_key", Opts),
-    decode(File, public_key).
+%% public_host_key(Type, Opts) ->
+%%     File = file_name(Type, "ssh_host_key", Opts),
+%%     decode(File, public_key).
  
 private_host_key(Type, Opts) ->
     File = file_name(Type, "ssh_host_key", Opts),
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index 3fef42a1ac..f99b9c9ca7 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -203,24 +203,24 @@ key_exchange_init_msg(Ssh0) ->
     {SshPacket, Ssh} = ssh_packet(Msg, Ssh0),
     {Msg, SshPacket, Ssh}.
 
-kex_init(#ssh{role = Role, opts = Opts}) ->
+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
 		      zlib -> ["zlib", "none"];
 		      none -> ["none", "zlib"]
 		  end,
-    kexinit_messsage(Role, Random, Compression).
+    kexinit_messsage(Role, Random, Compression, HostKeyAlgs).
 
 key_init(client, Ssh, Value) ->
     Ssh#ssh{c_keyinit = Value};
 key_init(server, Ssh, Value) ->
     Ssh#ssh{s_keyinit = Value}.
 
-kexinit_messsage(client, Random, Compression) ->
+kexinit_messsage(client, Random, Compression, HostKeyAlgs) ->
     #ssh_msg_kexinit{ 
 		  cookie = Random,
 		  kex_algorithms = ["diffie-hellman-group1-sha1"],
-		  server_host_key_algorithms = ["ssh-rsa", "ssh-dss"],
+		  server_host_key_algorithms = HostKeyAlgs,
 		  encryption_algorithms_client_to_server = ["aes128-cbc","3des-cbc"],
 		  encryption_algorithms_server_to_client = ["aes128-cbc","3des-cbc"],
 		  mac_algorithms_client_to_server = ["hmac-sha1"],
@@ -231,11 +231,11 @@ kexinit_messsage(client, Random, Compression) ->
 		  languages_server_to_client = []
 		 };
 
-kexinit_messsage(server, Random, Compression) ->
+kexinit_messsage(server, Random, Compression, HostKeyAlgs) ->
     #ssh_msg_kexinit{
 		  cookie = Random,
 		  kex_algorithms = ["diffie-hellman-group1-sha1"],
-		  server_host_key_algorithms = ["ssh-dss"],
+		  server_host_key_algorithms = HostKeyAlgs,
 		  encryption_algorithms_client_to_server = ["aes128-cbc","3des-cbc"],
 		  encryption_algorithms_server_to_client = ["aes128-cbc","3des-cbc"],
 		  mac_algorithms_client_to_server = ["hmac-sha1"],
@@ -426,8 +426,8 @@ get_host_key(SSH) ->
 		Error ->
 		    exit(Error)
 	    end;
-	_ ->
-	    exit({error, bad_key_type})
+	Foo ->
+	    exit({error, {Foo, bad_key_type}})
     end.
 
 sign_host_key(_Ssh, #'RSAPrivateKey'{} = Private, H) ->