feat: filter out messages which the source client is banned when delivering the retained message

apps/emqx_modules/test/emqx_delayed_SUITE.erl

@@ -37,8 +37,7 @@
 }).
 
 all() ->
-    [t_banned_delayed].
-%%    emqx_common_test_helpers:all(?MODULE).
+    emqx_common_test_helpers:all(?MODULE).
 
 init_per_suite(Config) ->
     ok = emqx_common_test_helpers:load_config(emqx_modules_schema, ?BASE_CONF, #{

apps/emqx_retainer/src/emqx_retainer_dispatcher.erl

@@ -20,6 +20,7 @@
 
 -include("emqx_retainer.hrl").
 -include_lib("emqx/include/logger.hrl").
+-include_lib("snabbkaffe/include/snabbkaffe.hrl").
 
 %% API
 -export([
@@ -286,7 +287,20 @@ do_deliver(Msgs, DeliverNum, Pid, Topic, Limiter) ->
     end.
 
 do_deliver([Msg | T], Pid, Topic) ->
-    Pid ! {deliver, Topic, Msg},
+    case emqx_banned:look_up({clientid, Msg#message.from}) of
+        [] ->
+            Pid ! {deliver, Topic, Msg},
+            ok;
+        _ ->
+            ?tp(
+                notice,
+                ignore_retained_message_deliver,
+                #{
+                    reason => "client is banned",
+                    clienid => Msg#message.from
+                }
+            )
+    end,
     do_deliver(T, Pid, Topic);
 do_deliver([], _, _) ->
     ok.

apps/emqx_retainer/test/emqx_retainer_SUITE.erl

@@ -639,6 +639,47 @@ test_disable_then_start(_Config) ->
     ?assertNotEqual([], gproc_pool:active_workers(emqx_retainer_dispatcher)),
     ok.
 
+t_deliver_when_banned(_) ->
+    ClientId = <<"c1">>,
+
+    {ok, C1} = emqtt:start_link([{clientid, ClientId}, {clean_start, true}, {proto_ver, v5}]),
+    {ok, _} = emqtt:connect(C1),
+
+    lists:foreach(
+        fun(I) ->
+            Topic = erlang:list_to_binary(io_lib:format("retained/~p", [I])),
+            emqtt:publish(
+                C1,
+                Topic,
+                <<"this is a retained message">>,
+                [{qos, 0}, {retain, true}]
+            )
+        end,
+        lists:seq(1, 3)
+    ),
+
+    Now = erlang:system_time(second),
+    Who = {clientid, ClientId},
+    emqx_banned:create(#{
+        who => Who,
+        by => <<"test">>,
+        reason => <<"test">>,
+        at => Now,
+        until => Now + 120
+    }),
+
+    timer:sleep(100),
+    snabbkaffe:start_trace(),
+    {ok, #{}, [0]} = emqtt:subscribe(C1, <<"retained/+">>, [{qos, 0}, {rh, 0}]),
+    timer:sleep(500),
+
+    Trace = snabbkaffe:collect_trace(),
+    ?assertEqual(3, length(?of_kind(ignore_retained_message_deliver, Trace))),
+    snabbkaffe:stop(),
+    emqx_banned:delete(Who),
+    {ok, #{}, [0]} = emqtt:unsubscribe(C1, <<"retained/+">>),
+    ok = emqtt:disconnect(C1).
+
 %%--------------------------------------------------------------------
 %% Helper functions
 %%--------------------------------------------------------------------