fix(listeners): Constraints the atom convert when parsing the esockd access rules

esockd rules only use words 'allow' and 'deny', both are existing,
so it is better to restrict the conversion and print a log when errors

apps/emqx/src/emqx_listeners.erl

@@ -49,7 +49,8 @@
 -export([
     listener_id/2,
     parse_listener_id/1,
-    ensure_override_limiter_conf/2
+    ensure_override_limiter_conf/2,
+    esockd_access_rules/1
 ]).
 
 -export([pre_config_update/3, post_config_update/5]).
@@ -497,17 +498,28 @@ ip_port({Addr, Port}) ->
     [{ip, Addr}, {port, Port}].
 
 esockd_access_rules(StrRules) ->
-    Access = fun(S) ->
+    Access = fun(S, Acc) ->
         [A, CIDR] = string:tokens(S, " "),
-        {
-            list_to_atom(A),
-            case CIDR of
-                "all" -> all;
-                _ -> CIDR
-            end
-        }
+        %% esockd rules only use words 'allow' and 'deny', both are existing
+        %% comparison of strings may be better, but there is a loss of backward compatibility
+        case emqx_misc:safe_to_existing_atom(A) of
+            {ok, Action} ->
+                [
+                    {
+                        Action,
+                        case CIDR of
+                            "all" -> all;
+                            _ -> CIDR
+                        end
+                    }
+                    | Acc
+                ];
+            _ ->
+                ?SLOG(warning, #{msg => "invalid esockd access rule", rule => S}),
+                Acc
+        end
     end,
-    [Access(R) || R <- StrRules].
+    lists:foldr(Access, [], StrRules).
 
 merge_default(Options) ->
     case lists:keytake(tcp_options, 1, Options) of

apps/emqx/src/emqx_misc.erl

@@ -469,9 +469,9 @@ safe_to_existing_atom(In) ->
     safe_to_existing_atom(In, utf8).
 
 safe_to_existing_atom(Bin, Encoding) when is_binary(Bin) ->
-    try_to_existing_atom(fun erlang:binary_to_existing_atom/2, [Bin, Encoding]);
-safe_to_existing_atom(List, _Encoding) when is_list(List) ->
-    try_to_existing_atom(fun erlang:list_to_existing_atom/1, [List]);
+    try_to_existing_atom(fun erlang:binary_to_existing_atom/2, Bin, Encoding);
+safe_to_existing_atom(List, Encoding) when is_list(List) ->
+    try_to_existing_atom(fun(In, _) -> erlang:list_to_existing_atom(In) end, List, Encoding);
 safe_to_existing_atom(Atom, _Encoding) when is_atom(Atom) ->
     {ok, Atom};
 safe_to_existing_atom(_Any, _Encoding) ->
@@ -547,8 +547,8 @@ readable_error_msg(Error) ->
             end
     end.
 
-try_to_existing_atom(Fun, Args) ->
-    try erlang:apply(Fun, Args) of
+try_to_existing_atom(Convert, Data, Encoding) ->
+    try Convert(Data, Encoding) of
         Atom ->
             {ok, Atom}
     catch

apps/emqx_gateway/src/coap/handler/emqx_coap_pubsub_handler.erl

@@ -121,13 +121,7 @@ apply_publish_opts(Msg, MQTTMsg) ->
             maps:fold(
                 fun
                     (<<"retain">>, V, Acc) ->
-                        Val =
-                            case emqx_misc:safe_to_existing_atom(V) of
-                                {ok, true} ->
-                                    true;
-                                _ ->
-                                    false
-                            end,
+                        Val = V =:= <<"true">>,
                         emqx_message:set_flag(retain, Val, Acc);
                     (<<"expiry">>, V, Acc) ->
                         Val = erlang:binary_to_integer(V),

apps/emqx_gateway/src/emqx_gateway_utils.erl

@@ -70,6 +70,8 @@
     default_subopts/0
 ]).
 
+-import(emqx_listeners, [esockd_access_rules/1]).
+
 -define(ACTIVE_N, 100).
 -define(DEFAULT_IDLE_TIMEOUT, 30000).
 -define(DEFAULT_GC_OPTS, #{count => 1000, bytes => 1024 * 1024}).
@@ -443,19 +445,6 @@ esockd_opts(Type, Opts0) ->
         end
     ).
 
-esockd_access_rules(StrRules) ->
-    Access = fun(S) ->
-        [A, CIDR] = string:tokens(S, " "),
-        {
-            list_to_atom(A),
-            case CIDR of
-                "all" -> all;
-                _ -> CIDR
-            end
-        }
-    end,
-    [Access(R) || R <- StrRules].
-
 ssl_opts(Name, Opts) ->
     Type =
         case Name of