fix(conn): avoid storing incomplete channel info

apps/emqx/src/emqx_cm.erl

@@ -133,6 +133,10 @@
 %% Server name
 -define(CM, ?MODULE).
 
+-define(IS_CLIENTID(CLIENTID),
+    (is_binary(CLIENTID) orelse (is_atom(CLIENTID) andalso CLIENTID =/= undefined))
+).
+
 %% linting overrides
 -elvis([
     {elvis_style, invalid_dynamic_call, #{ignore => [emqx_cm]}},
@@ -154,7 +158,7 @@ start_link() ->
     emqx_types:infos(),
     emqx_types:stats()
 ) -> ok.
-insert_channel_info(ClientId, Info, Stats) ->
+insert_channel_info(ClientId, Info, Stats) when ?IS_CLIENTID(ClientId) ->
     Chan = {ClientId, self()},
     true = ets:insert(?CHAN_INFO_TAB, {Chan, Info, Stats}),
     ?tp(debug, insert_channel_info, #{clientid => ClientId}),
@@ -168,7 +172,9 @@ insert_channel_info(ClientId, Info, Stats) ->
 %% the conn_mod first for taking up the clientid access right.
 %%
 %% Note that: It should be called on a lock transaction
-register_channel(ClientId, ChanPid, #{conn_mod := ConnMod}) when is_pid(ChanPid) ->
+register_channel(ClientId, ChanPid, #{conn_mod := ConnMod}) when
+    is_pid(ChanPid) andalso ?IS_CLIENTID(ClientId)
+->
     Chan = {ClientId, ChanPid},
     %% cast (for process monitor) before inserting ets tables
     cast({registered, Chan}),
@@ -180,7 +186,7 @@ register_channel(ClientId, ChanPid, #{conn_mod := ConnMod}) when is_pid(ChanPid)
 
 %% @doc Unregister a channel.
 -spec unregister_channel(emqx_types:clientid()) -> ok.
-unregister_channel(ClientId) when is_binary(ClientId) ->
+unregister_channel(ClientId) when ?IS_CLIENTID(ClientId) ->
     true = do_unregister_channel({ClientId, self()}),
     ok.
 
@@ -215,7 +221,7 @@ get_chan_info(ClientId, ChanPid) ->
 
 %% @doc Update infos of the channel.
 -spec set_chan_info(emqx_types:clientid(), emqx_types:attrs()) -> boolean().
-set_chan_info(ClientId, Info) when is_binary(ClientId) ->
+set_chan_info(ClientId, Info) when ?IS_CLIENTID(ClientId) ->
     Chan = {ClientId, self()},
     try
         ets:update_element(?CHAN_INFO_TAB, Chan, {2, Info})
@@ -245,12 +251,12 @@ get_chan_stats(ClientId, ChanPid) ->
 
 %% @doc Set channel's stats.
 -spec set_chan_stats(emqx_types:clientid(), emqx_types:stats()) -> boolean().
-set_chan_stats(ClientId, Stats) when is_binary(ClientId) ->
+set_chan_stats(ClientId, Stats) when ?IS_CLIENTID(ClientId) ->
     set_chan_stats(ClientId, self(), Stats).
 
 -spec set_chan_stats(emqx_types:clientid(), chan_pid(), emqx_types:stats()) ->
     boolean().
-set_chan_stats(ClientId, ChanPid, Stats) ->
+set_chan_stats(ClientId, ChanPid, Stats) when ?IS_CLIENTID(ClientId) ->
     Chan = {ClientId, ChanPid},
     try
         ets:update_element(?CHAN_INFO_TAB, Chan, {3, Stats})

apps/emqx/src/emqx_connection.erl

@@ -638,8 +638,11 @@ handle_msg({event, disconnected}, State = #state{channel = Channel}) ->
     emqx_cm:set_chan_info(ClientId, info(State)),
     {ok, State};
 handle_msg({event, _Other}, State = #state{channel = Channel}) ->
-    ClientId = emqx_channel:info(clientid, Channel),
-    emqx_cm:insert_channel_info(ClientId, info(State), stats(State)),
+    case emqx_channel:info(clientid, Channel) of
+        %% ClientId is yet unknown (i.e. connect packet is not received yet)
+        undefined -> ok;
+        ClientId -> emqx_cm:insert_channel_info(ClientId, info(State), stats(State))
+    end,
     {ok, State};
 handle_msg({timeout, TRef, TMsg}, State) ->
     handle_timeout(TRef, TMsg, State);

apps/emqx/src/emqx_ws_connection.erl

@@ -533,9 +533,14 @@ handle_info({event, disconnected}, State = #state{channel = Channel}) ->
     emqx_cm:set_chan_info(ClientId, info(State)),
     return(State);
 handle_info({event, _Other}, State = #state{channel = Channel}) ->
-    ClientId = emqx_channel:info(clientid, Channel),
-    emqx_cm:set_chan_info(ClientId, info(State)),
-    emqx_cm:set_chan_stats(ClientId, stats(State)),
+    case emqx_channel:info(clientid, Channel) of
+        %% ClientId is yet unknown (i.e. connect packet is not received yet)
+        undefined ->
+            ok;
+        ClientId ->
+            emqx_cm:set_chan_info(ClientId, info(State)),
+            emqx_cm:set_chan_stats(ClientId, stats(State))
+    end,
     return(State);
 handle_info(Info, State) ->
     with_channel(handle_info, [Info], State).

apps/emqx/test/emqx_cm_SUITE.erl

@@ -81,7 +81,12 @@ t_get_set_chan_info(_) ->
     true = emqx_cm:set_chan_info(<<"clientid">>, Info1),
     ?assertEqual(Info1, emqx_cm:get_chan_info(<<"clientid">>)),
     ok = emqx_cm:unregister_channel(<<"clientid">>),
-    ?assertEqual(undefined, emqx_cm:get_chan_info(<<"clientid">>)).
+    ?assertEqual(undefined, emqx_cm:get_chan_info(<<"clientid">>)),
+
+    ?assertError(
+        function_clause,
+        emqx_cm:insert_channel_info(undefined, #{}, [])
+    ).
 
 t_get_set_chan_stats(_) ->
     Stats = [{recv_oct, 10}, {send_oct, 8}],
@@ -93,6 +98,12 @@ t_get_set_chan_stats(_) ->
     Stats1 = [{recv_oct, 10} | Stats],
     true = emqx_cm:set_chan_stats(<<"clientid">>, Stats1),
     ?assertEqual(Stats1, emqx_cm:get_chan_stats(<<"clientid">>)),
+
+    ?assertError(
+        function_clause,
+        emqx_cm:set_chan_stats(undefined, [])
+    ),
+
     ok = emqx_cm:unregister_channel(<<"clientid">>),
     ?assertEqual(undefined, emqx_cm:get_chan_stats(<<"clientid">>)).
 

apps/emqx/test/emqx_connection_conninfo_SUITE.erl

@@ -0,0 +1,67 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2019-2023 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_connection_conninfo_SUITE).
+
+-compile(export_all).
+-compile(nowarn_export_all).
+
+-include_lib("eunit/include/eunit.hrl").
+-include_lib("common_test/include/ct.hrl").
+
+all() ->
+    emqx_common_test_helpers:all(?MODULE).
+
+init_per_suite(Config) ->
+    Config.
+
+end_per_suite(_Config) ->
+    ok.
+
+init_per_testcase(Case, Config) ->
+    Apps = emqx_cth_suite:start(
+        [
+            {emqx,
+                "listeners.tcp.default {\n"
+                "   tcp_options {\n"
+                "       recbuf = 10\n"
+                "       buffer = 10\n"
+                "       active_n = 1\n"
+                "   }\n"
+                "   messages_rate = \"1/1s\"\n"
+                "   bytes_rate = \"1KB/1s\"\n"
+                "}\n"}
+        ],
+        #{work_dir => emqx_cth_suite:work_dir(Case, Config)}
+    ),
+    [{apps, Apps} | Config].
+
+end_per_testcase(_Case, Config) ->
+    emqx_cth_suite:stop(?config(apps, Config)).
+
+t_inconsistent_chan_info(_Config) ->
+    {ok, C} = emqtt:start_link([{clientid, emqx_guid:to_hexstr(emqx_guid:gen())}]),
+    {ok, _} = emqtt:connect(C),
+    ok = emqtt:disconnect(C),
+
+    ClientIds = [
+        ClientId
+     || {ClientId, _ConnState, _ConnInfo, _ClientInfo} <- qlc:eval(
+            emqx_cm:all_channels_table([emqx_connection])
+        )
+    ],
+
+    ?assertNot(lists:member(undefined, ClientIds)).

changes/ce/fix-12305.en.md

@@ -0,0 +1 @@
+Eliminated passing incomplete client/connection information into `emqx_cm`. This could lead to internal inconsistency and affect memory consumption and some processes like node evacuation.