Merge branch 'hans/ssh/robust_pubkey_prechecks/OTP-15424' into maint

* hans/ssh/robust_pubkey_prechecks/OTP-15424:
  ssh: Make host and user key pre-checking better
  ssh: Generalize unpublished test support option
  ssh: Cleaning and polishing of ssh_auth
  ssh: Add a common key_cb call function

1 files changed, 64 insertions, 48 deletions

diff --git a/lib/ssh/src/ssh_auth.erl b/lib/ssh/src/ssh_auth.erl
index 4e4aa440de..9632168e65 100644
--- a/lib/ssh/src/ssh_auth.erl
+++ b/lib/ssh/src/ssh_auth.erl
@@ -91,8 +91,10 @@ unique(L) ->
     
 
 %%%---- userauth_request_msg "callbacks"
-password_msg([#ssh{opts = Opts, io_cb = IoCb,
-		   user = User, service = Service} = Ssh0]) ->
+password_msg([#ssh{opts = Opts,
+		   user = User,
+                   service = Service} = Ssh0]) ->
+    IoCb = ?GET_INTERNAL_OPT(io_cb, Opts),
     {Password,Ssh} = 
 	case ?GET_OPT(password, Opts) of
 	    undefined when IoCb == ssh_no_io ->
@@ -137,9 +139,7 @@ keyboard_interactive_msg([#ssh{user = User,
 
 get_public_key(SigAlg, #ssh{opts = Opts}) ->
     KeyAlg = key_alg(SigAlg),
-    {KeyCb,KeyCbOpts} = ?GET_OPT(key_cb, Opts),
-    UserOpts = ?GET_OPT(user_options, Opts),
-    case KeyCb:user_key(KeyAlg, [{key_cb_private,KeyCbOpts}|UserOpts]) of
+    case ssh_transport:call_KeyCb(user_key, [KeyAlg], Opts) of
         {ok, PrivKey} ->
             try
                 %% Check the key - the KeyCb may be a buggy plugin
@@ -387,11 +387,9 @@ handle_userauth_info_request(#ssh_msg_userauth_info_request{name = Name,
 							    instruction = Instr,
 							    num_prompts = NumPrompts,
 							    data  = Data},
-			     #ssh{opts = Opts,
-				  io_cb = IoCb
-				 } = Ssh) ->
+			     #ssh{opts=Opts} = Ssh) ->
     PromptInfos = decode_keyboard_interactive_prompts(NumPrompts,Data),
-    case keyboard_interact_get_responses(IoCb, Opts, Name, Instr, PromptInfos) of
+    case keyboard_interact_get_responses(Opts, Name, Instr, PromptInfos) of
 	not_ok ->
 	    not_ok;
 	Responses ->
@@ -498,9 +496,7 @@ get_password_option(Opts, User) ->
 pre_verify_sig(User, KeyBlob, Opts) ->
     try
 	Key = public_key:ssh_decode(KeyBlob, ssh2_pubkey), % or exception
-        {KeyCb,KeyCbOpts} = ?GET_OPT(key_cb, Opts),
-        UserOpts = ?GET_OPT(user_options, Opts),
-        KeyCb:is_auth_key(Key, User, [{key_cb_private,KeyCbOpts}|UserOpts])
+        ssh_transport:call_KeyCb(is_auth_key, [Key, User], Opts)
     catch
 	_:_ ->
 	    false
@@ -509,10 +505,8 @@ pre_verify_sig(User, KeyBlob, Opts) ->
 verify_sig(SessionId, User, Service, AlgBin, KeyBlob, SigWLen, #ssh{opts = Opts} = Ssh) ->
     try
         Alg = binary_to_list(AlgBin),
-        {KeyCb,KeyCbOpts} = ?GET_OPT(key_cb, Opts),
-        UserOpts = ?GET_OPT(user_options, Opts),
         Key = public_key:ssh_decode(KeyBlob, ssh2_pubkey), % or exception
-        true = KeyCb:is_auth_key(Key, User, [{key_cb_private,KeyCbOpts}|UserOpts]),
+        true = ssh_transport:call_KeyCb(is_auth_key, [Key, User], Opts),
         PlainText = build_sig_data(SessionId, User, Service, KeyBlob, Alg),
         <<?UINT32(AlgSigLen), AlgSig:AlgSigLen/binary>> = SigWLen,
         <<?UINT32(AlgLen), _Alg:AlgLen/binary,
@@ -536,56 +530,78 @@ build_sig_data(SessionId, User, Service, KeyBlob, Alg) ->
 
 
 
+key_alg('rsa-sha2-256') -> 'ssh-rsa';
+key_alg('rsa-sha2-512') -> 'ssh-rsa';
+key_alg(Alg) -> Alg.
+
+%%%================================================================
+%%%
+%%% Keyboard-interactive
+%%% 
+
 decode_keyboard_interactive_prompts(_NumPrompts, Data) ->
     ssh_message:decode_keyboard_interactive_prompts(Data, []).
 
-keyboard_interact_get_responses(IoCb, Opts, Name, Instr, PromptInfos) ->
-    NumPrompts = length(PromptInfos),
+keyboard_interact_get_responses(Opts, Name, Instr, PromptInfos) ->
     keyboard_interact_get_responses(?GET_OPT(user_interaction, Opts),
 				    ?GET_OPT(keyboard_interact_fun, Opts),
-				    ?GET_OPT(password, Opts), IoCb, Name,
-				    Instr, PromptInfos, Opts, NumPrompts).
+				    ?GET_OPT(password, Opts),
+                                    Name,
+				    Instr,
+                                    PromptInfos,
+                                    Opts).
 
 
-keyboard_interact_get_responses(_, _, not_ok, _, _, _, _, _, _) ->
+%% Don't re-try an already rejected password. This could happen if both keyboard-interactive
+%% and password methods are tried:
+keyboard_interact_get_responses(_, _, not_ok, _, _, _, _) ->
     not_ok;
-keyboard_interact_get_responses(_, undefined, Password, _, _, _, _, _,
-				1) when Password =/= undefined ->
-    [Password]; %% Password auth implemented with keyboard-interaction and passwd is known
-keyboard_interact_get_responses(_, _, _, _, _, _, _, _, 0)  ->
+
+%% Only one password requestedm and we have got one via the 'password' option for the daemon:
+keyboard_interact_get_responses(_, undefined, Pwd, _, _, [_], _) when Pwd =/= undefined ->
+    [Pwd]; %% Password auth implemented with keyboard-interaction and passwd is known
+
+%% No password requested (keyboard-interactive):
+keyboard_interact_get_responses(_, _, _, _, _, [], _)  ->
     [];
-keyboard_interact_get_responses(false, undefined, undefined, _, _, _, [Prompt|_], Opts, _) ->
-    ssh_no_io:read_line(Prompt, Opts); %% Throws error as keyboard interaction is not allowed
-keyboard_interact_get_responses(true, undefined, _,IoCb, Name, Instr, PromptInfos, Opts, _) ->
-    keyboard_interact(IoCb, Name, Instr, PromptInfos, Opts);
-keyboard_interact_get_responses(true, Fun, _Pwd, _IoCb, Name, Instr, PromptInfos, _Opts, NumPrompts) ->
-    keyboard_interact_fun(Fun, Name, Instr, PromptInfos, NumPrompts).
-
-keyboard_interact(IoCb, Name, Instr, Prompts, Opts) ->
+
+%% user_interaction is forbidden (by option user_interaction) and we have to ask
+%% the user for one or more.
+%% Throw an error:
+keyboard_interact_get_responses(false, undefined, undefined, _, _, [Prompt|_], Opts) ->
+    ssh_no_io:read_line(Prompt, Opts);
+
+%% One or more passwords are requested, we may prompt the user and no fun is used
+%% to get the responses:
+keyboard_interact_get_responses(true, undefined, _, Name, Instr, PromptInfos, Opts) ->
+    prompt_user_for_passwords(Name, Instr, PromptInfos, Opts);
+
+%% The passwords are provided with a fun. Use that one!
+keyboard_interact_get_responses(true, Fun, _Pwd, Name, Instr, PromptInfos, _Opts) ->
+    keyboard_interact_fun(Fun, Name, Instr, PromptInfos).
+
+
+
+prompt_user_for_passwords(Name, Instr, PromptInfos, Opts) ->
+    IoCb = ?GET_INTERNAL_OPT(io_cb, Opts),
     write_if_nonempty(IoCb, Name),
     write_if_nonempty(IoCb, Instr),
     lists:map(fun({Prompt, true})  -> IoCb:read_line(Prompt, Opts);
 		 ({Prompt, false}) -> IoCb:read_password(Prompt, Opts)
 	      end,
-	      Prompts).
+	      PromptInfos).
 
-write_if_nonempty(_, "") -> ok;
-write_if_nonempty(_, <<>>) -> ok;
-write_if_nonempty(IoCb, Text) -> IoCb:format("~s~n",[Text]).
-
-
-keyboard_interact_fun(KbdInteractFun, Name, Instr,  PromptInfos, NumPrompts) ->
-    Prompts = lists:map(fun({Prompt, _Echo}) -> Prompt end,
-			PromptInfos),
-    case KbdInteractFun(Name, Instr, Prompts) of
-	Rs when length(Rs) == NumPrompts ->
-	    Rs;
-	_Rs ->
+keyboard_interact_fun(KbdInteractFun, Name, Instr,  PromptInfos) ->
+    case KbdInteractFun(Name, Instr, PromptInfos) of
+	Responses when is_list(Responses),
+                     length(Responses) == length(PromptInfos) ->
+	    Responses;
+	_ ->
             nok
     end.
 
 
-key_alg('rsa-sha2-256') -> 'ssh-rsa';
-key_alg('rsa-sha2-512') -> 'ssh-rsa';
-key_alg(Alg) -> Alg.
+write_if_nonempty(_, "") -> ok;
+write_if_nonempty(_, <<>>) -> ok;
+write_if_nonempty(IoCb, Text) -> IoCb:format("~s~n",[Text]).