Merge branch 'hans/ssh/no_common_algs/OTP-11531' into maint

* hans/ssh/no_common_algs/OTP-11531:
  ssh: testcases for no common algorithms in key exchange

4 files changed, 120 insertions, 12 deletions

diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index f4e6a23a1e..2e7391e1f8 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -246,26 +246,41 @@ handle_kexinit_msg(#ssh_msg_kexinit{} = CounterPart, #ssh_msg_kexinit{} = Own,
 				   Ssh0#ssh{algorithms = Algoritms});
 	_  ->
 	    %% TODO: Correct code?
-	    throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_PROTOCOL_ERROR,
+	    throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
 				      description = "Selection of key exchange"
 				      " algorithm failed", 
-				      language = "en"})
+				      language = ""})
     end;
 
 handle_kexinit_msg(#ssh_msg_kexinit{} = CounterPart, #ssh_msg_kexinit{} = Own,
 			    #ssh{role = server} = Ssh) ->
     {ok, Algoritms} = select_algorithm(server, CounterPart, Own),
-    {ok, Ssh#ssh{algorithms = Algoritms}}.
+    case  verify_algorithm(Algoritms) of
+	true ->
+	    {ok, Ssh#ssh{algorithms = Algoritms}};
+	_ ->
+	    throw(#ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
+				      description = "Selection of key exchange"
+				      " algorithm failed",
+				      language = ""})
+    end.
 
 
 %% TODO: diffie-hellman-group14-sha1 should also be supported.
 %% Maybe check more things ...
-verify_algorithm(#alg{kex = 'diffie-hellman-group1-sha1'}) ->
-    true;
-verify_algorithm(#alg{kex = 'diffie-hellman-group-exchange-sha1'}) ->
-    true;
-verify_algorithm(_) ->
-    false.
+
+verify_algorithm(#alg{kex = undefined}) -> false;
+verify_algorithm(#alg{hkey = undefined}) -> false;
+verify_algorithm(#alg{send_mac = undefined}) -> false;
+verify_algorithm(#alg{recv_mac = undefined}) -> false;
+verify_algorithm(#alg{encrypt = undefined}) -> false;
+verify_algorithm(#alg{decrypt = undefined}) -> false;
+verify_algorithm(#alg{compress = undefined}) -> false;
+verify_algorithm(#alg{decompress = undefined}) -> false;
+
+verify_algorithm(#alg{kex = 'diffie-hellman-group1-sha1'}) -> true;
+verify_algorithm(#alg{kex = 'diffie-hellman-group-exchange-sha1'}) -> true;
+verify_algorithm(_) -> false.
 
 key_exchange_first_msg('diffie-hellman-group1-sha1', Ssh0) ->
     {G, P} = dh_group1(),
diff --git a/lib/ssh/test/ssh_basic_SUITE.erl b/lib/ssh/test/ssh_basic_SUITE.erl
index 9ff3eb8d0b..bf9fe54c57 100644
--- a/lib/ssh/test/ssh_basic_SUITE.erl
+++ b/lib/ssh/test/ssh_basic_SUITE.erl
@@ -1838,6 +1838,8 @@ check_error("Invalid state") ->
     ok;
 check_error("Connection closed") ->
     ok;
+check_error("Selection of key exchange algorithm failed") ->
+    ok;
 check_error(Error) ->
     ct:fail(Error).
 
diff --git a/lib/ssh/test/ssh_protocol_SUITE.erl b/lib/ssh/test/ssh_protocol_SUITE.erl
index 3fb2840a19..58c8306c31 100644
--- a/lib/ssh/test/ssh_protocol_SUITE.erl
+++ b/lib/ssh/test/ssh_protocol_SUITE.erl
@@ -45,7 +45,8 @@ suite() ->
     [{ct_hooks,[ts_install_cth]}].
 
 all() -> 
-    [{group,tool_tests}
+    [{group,tool_tests},
+     {group,kex}
     ].
 
 groups() ->
@@ -53,7 +54,10 @@ groups() ->
 		       lib_works_as_server,
 		       lib_match,
 		       lib_no_match
-		      ]}
+		      ]},
+     {kex, [], [no_common_alg_server_disconnects,
+		no_common_alg_client_disconnects
+		]}
     ].
 
 
@@ -203,6 +207,91 @@ lib_no_match(_Config) ->
 	{error, {_Op,{expected,a,b},_State}} -> ok
     end.
 
+%%--------------------------------------------------------------------
+%%% Algo negotiation fail.  This should result in a ssh_msg_disconnect
+%%% being sent from the server.
+no_common_alg_server_disconnects(Config) ->
+    {ok,_} =
+	ssh_trpt_test_lib:exec(
+	  [{set_options, [print_ops, print_seqnums, print_messages]},
+	   {connect,
+	    server_host(Config),server_port(Config),
+	    [{silently_accept_hosts, true},
+	     {user_dir, user_dir(Config)},
+	     {user_interaction, false},
+	     {preferred_algorithms,[{public_key,['ssh-dss']}]}
+	    ]},
+	   receive_hello,
+	   {send, hello},
+	   {match, #ssh_msg_kexinit{_='_'}, receive_msg},
+	   {send, ssh_msg_kexinit},
+	   {match,
+	    #ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED,  _='_'},
+	    receive_msg}
+	  ]
+	 ).
+
+%%--------------------------------------------------------------------
+%%% Algo negotiation fail.  This should result in a ssh_msg_disconnect
+%%% being sent from the client.
+no_common_alg_client_disconnects(Config) ->
+    %% Create a listening socket as server socket:
+    {ok,InitialState} = ssh_trpt_test_lib:exec(listen),
+    HostPort = ssh_trpt_test_lib:server_host_port(InitialState),
+    Parent = self(),
+
+    %% Start a process handling one connection on the server side:
+    Pid =
+	spawn_link(
+	  fun() ->
+		  Parent !
+		      {result,self(),
+		       ssh_trpt_test_lib:exec(
+			 [{set_options, [print_ops, print_messages]},
+			  {accept, [{system_dir, system_dir(Config)},
+				    {user_dir, user_dir(Config)}]},
+			  receive_hello,
+			  {send, hello},
+
+			  {match, #ssh_msg_kexinit{_='_'}, receive_msg},
+			  {send,  #ssh_msg_kexinit{
+				     cookie = 247381486335508958743193106082599558706,
+				     kex_algorithms = ["diffie-hellman-group1-sha1"],
+				     server_host_key_algorithms = ["some-unknown"],
+				     encryption_algorithms_client_to_server = ["aes128-ctr"],
+				     encryption_algorithms_server_to_client = ["aes128-ctr"],
+				     mac_algorithms_client_to_server = ["hmac-sha2-256"],
+				     mac_algorithms_server_to_client = ["hmac-sha2-256"],
+				     compression_algorithms_client_to_server = ["none"],
+				     compression_algorithms_server_to_client = ["none"],
+				     languages_client_to_server = [],
+				     languages_server_to_client = [],
+				     first_kex_packet_follows = false,
+				     reserved = 0
+				    }},
+
+			  {match,
+			   #ssh_msg_disconnect{code = ?SSH_DISCONNECT_KEY_EXCHANGE_FAILED,  _='_'},
+			   receive_msg}
+			 ],
+			 InitialState)
+		      }
+	  end),
+
+    %% and finally connect to it with a regular Erlang SSH client:
+    Result = std_connect(HostPort, Config, [{preferred_algorithms,[{public_key,['ssh-dss']}]}]),
+    ct:log("Result of connect is ~p",[Result]),
+
+    receive
+	{result,Pid,{ok,_}} -> 
+	    ok;
+	{result,Pid,{error,{Op,ExecResult,S}}} ->
+	    ct:pal("ERROR!~nOp = ~p~nExecResult = ~p~nState =~n~s",
+		   [Op,ExecResult,ssh_trpt_test_lib:format_msg(S)]),
+	    {fail, ExecResult};
+	X -> ct:fail(X)
+    end.
+
 %%%================================================================
 %%%==== Internal functions ========================================
 %%%================================================================
diff --git a/lib/ssh/test/ssh_trpt_test_lib.erl b/lib/ssh/test/ssh_trpt_test_lib.erl
index 8623020a31..a604fca1ac 100644
--- a/lib/ssh/test/ssh_trpt_test_lib.erl
+++ b/lib/ssh/test/ssh_trpt_test_lib.erl
@@ -200,7 +200,9 @@ op_val(E, S0) ->
 	{'EXIT',{function_clause,[{ssh_trpt_test_lib,op,[E,S0],_}|_]}} ->
 	    {instantiate(E,S0), S0};
 	S=#s{} ->
-	    {S#s.return_value, S}
+	    {S#s.return_value, S};
+	F={fail,receive_timeout,_St} ->
+	    throw(F)
     end.