Add TLS certificate authentication for MQTT connections

1 files changed, 87 insertions, 13 deletions

diff --git a/src/mod_mqtt_session.erl b/src/mod_mqtt_session.erl
index 8ce04066..6a551f00 100644
--- a/src/mod_mqtt_session.erl
+++ b/src/mod_mqtt_session.erl
@@ -29,6 +29,7 @@
 -include("logger.hrl").
 -include("mqtt.hrl").
 -include_lib("xmpp/include/xmpp.hrl").
+-include_lib("public_key/include/public_key.hrl").
 
 -record(state, {vsn = ?VSN            :: integer(),
                 version               :: undefined | mqtt_version(),
@@ -47,7 +48,8 @@
 		in_flight             :: undefined | publish() | pubrel(),
 		codec                 :: mqtt_codec:state(),
 		queue                 :: undefined | p1_queue:queue(publish()),
-		tls                   :: boolean()}).
+		tls                   :: boolean(),
+		tls_verify            :: boolean()}).
 
 -type acks() :: #{non_neg_integer() => pubrec()}.
 -type subscriptions() :: #{binary() => {sub_opts(), non_neg_integer()}}.
@@ -162,6 +164,7 @@ init([SockMod, Socket, ListenOpts]) ->
     State1 = #state{socket = {SockMod, Socket},
 		    id = p1_rand:uniform(65535),
 		    tls = proplists:get_bool(tls, ListenOpts),
+		    tls_verify = proplists:get_bool(tls_verify, ListenOpts),
 		    codec = mqtt_codec:new(MaxSize)},
     Timeout = timer:seconds(30),
     State2 = set_timeout(State1, Timeout),
@@ -553,7 +556,7 @@ unregister_session(_, _) ->
 					    {error, state(), error_reason()}.
 handle_connect(#connect{clean_start = CleanStart} = Pkt,
 	       #state{jid = undefined, peername = IP} = State) ->
-    case authenticate(Pkt, IP) of
+    case authenticate(Pkt, IP, State) of
         {ok, JID} ->
             case validate_will(Pkt, JID) of
                 ok ->
@@ -939,7 +942,12 @@ check_sock_result({_, Sock}, {error, Why}) ->
 starttls(#state{socket = {gen_tcp, Socket}, tls = true}) ->
     case ejabberd_pkix:get_certfile() of
 	{ok, Cert} ->
-	    case fast_tls:tcp_to_tls(Socket, [{certfile, Cert}]) of
+            CAFileOpt =
+                case ejabberd_option:c2s_cafile(ejabberd_config:get_myname()) of
+                    undefined -> [];
+                    CAFile -> [{cafile, CAFile}]
+                end,
+	    case fast_tls:tcp_to_tls(Socket, [{certfile, Cert}] ++ CAFileOpt) of
 		{ok, TLSSock} ->
 		    {ok, {fast_tls, TLSSock}};
 		{error, Why} ->
@@ -1172,9 +1180,9 @@ parse_credentials(JID, ClientID) ->
             end
     end.
 
--spec authenticate(connect(), peername()) -> {ok, jid:jid()} | {error, reason_code()}.
-authenticate(Pkt, IP) ->
-    case authenticate(Pkt) of
+-spec authenticate(connect(), peername(), state()) -> {ok, jid:jid()} | {error, reason_code()}.
+authenticate(Pkt, IP, State) ->
+    case authenticate(Pkt, State) of
 	{ok, JID, AuthModule} ->
 	    ?INFO_MSG("Accepted MQTT authentication for ~ts by ~s backend from ~s",
 		      [jid:encode(JID),
@@ -1185,8 +1193,8 @@ authenticate(Pkt, IP) ->
 	    Err
     end.
 
--spec authenticate(connect()) -> {ok, jid:jid(), module()} | {error, reason_code()}.
-authenticate(#connect{password = Pass, properties = Props} = Pkt) ->
+-spec authenticate(connect(), state()) -> {ok, jid:jid(), module()} | {error, reason_code()}.
+authenticate(#connect{password = Pass, properties = Props} = Pkt, State) ->
     case parse_credentials(Pkt) of
 	{ok, #jid{luser = LUser, lserver = LServer} = JID} ->
 	    case maps:find(authentication_method, Props) of
@@ -1200,16 +1208,82 @@ authenticate(#connect{password = Pass, properties = Props} = Pkt) ->
 		{ok, _} ->
 		    {error, 'bad-authentication-method'};
 		error ->
-		    case ejabberd_auth:check_password_with_authmodule(
-			   LUser, <<>>, LServer, Pass) of
-			{true, AuthModule} -> {ok, JID, AuthModule};
-			false -> {error, 'not-authorized'}
-		    end
+                    case Pass of
+                        <<>> ->
+                            case tls_auth(JID, State) of
+                                true ->
+                                    {ok, JID, pkix};
+                                false ->
+                                    {error, 'not-authorized'}
+                            end;
+                        _ ->
+                            case ejabberd_auth:check_password_with_authmodule(
+                                   LUser, <<>>, LServer, Pass) of
+                                {true, AuthModule} -> {ok, JID, AuthModule};
+                                false -> {error, 'not-authorized'}
+                            end
+                    end
 	    end;
 	{error, _} = Err ->
 	    Err
     end.
 
+-spec tls_auth(jid:jid(), state()) -> boolean().
+tls_auth(_JID, #state{tls_verify = false}) ->
+    false;
+tls_auth(JID, State) ->
+    case State#state.socket of
+        {fast_tls, Sock} ->
+            case fast_tls:get_peer_certificate(Sock, otp) of
+                {ok, Cert} ->
+                    case fast_tls:get_verify_result(Sock) of
+                        0 ->
+                            case get_cert_jid(Cert) of
+                                {ok, JID2} ->
+                                    jid:remove_resource(jid:tolower(JID)) ==
+                                        jid:remove_resource(jid:tolower(JID2));
+                                error ->
+                                    false
+                            end;
+                        VerifyRes ->
+                            Reason = fast_tls:get_cert_verify_string(VerifyRes, Cert),
+                            ?WARNING_MSG("TLS verify failed: ~s", [Reason]),
+                            false
+                    end;
+                error ->
+                    false
+            end;
+        _ ->
+            false
+    end.
+
+get_cert_jid(Cert) ->
+    case Cert#'OTPCertificate'.tbsCertificate#'OTPTBSCertificate'.subject of
+        {rdnSequence, Attrs1} ->
+            Attrs = lists:flatten(Attrs1),
+            case lists:keyfind(?'id-at-commonName',
+                               #'AttributeTypeAndValue'.type, Attrs) of
+                #'AttributeTypeAndValue'{value = {utf8String, Val}} ->
+                    try jid:decode(Val) of
+                        #jid{luser = <<>>} ->
+                            case jid:make(Val, ejabberd_config:get_myname()) of
+                                error ->
+                                    error;
+                                JID ->
+                                    {ok, JID}
+                            end;
+                        JID ->
+                            {ok, JID}
+                    catch _:{bad_jid, _} ->
+                            error
+                    end;
+                _ ->
+                    error
+            end;
+        _ ->
+            error
+    end.
+
 %%%===================================================================
 %%% Validators
 %%%===================================================================