fix(auth_ldap): Handle missing attributes

Fixes: #4953

apps/emqx_auth_ldap/src/emqx_acl_ldap.erl

@@ -27,10 +27,6 @@
         , description/0
         ]).
 
--import(proplists, [get_value/2]).
-
--import(emqx_auth_ldap_cli, [search/4]).
-
 -spec(register_metrics() -> ok).
 register_metrics() ->
     lists:foreach(fun emqx_metrics:ensure/1, ?ACL_METRICS).
@@ -70,14 +66,14 @@ do_check_acl(#{username := Username}, PubSub, Topic, _NoMatchAction,
 
     BaseDN = emqx_auth_ldap:replace_vars(CustomBaseDN, ReplaceRules),
 
-    case search(Pool, BaseDN, Filter, [Attribute, Attribute1]) of
+    case emqx_auth_ldap_cli:search(Pool, BaseDN, Filter, [Attribute, Attribute1]) of
         {error, noSuchObject} ->
             ok;
         {ok, #eldap_search_result{entries = []}} ->
             ok;
         {ok, #eldap_search_result{entries = [Entry]}} ->
-            Topics = get_value(Attribute, Entry#eldap_entry.attributes)
-                ++ get_value(Attribute1, Entry#eldap_entry.attributes),
+            Topics = proplists:get_value(Attribute, Entry#eldap_entry.attributes, [])
+                ++ proplists:get_value(Attribute1, Entry#eldap_entry.attributes, []),
             match(Topic, Topics);
         Error ->
             ?LOG(error, "[LDAP] search error:~p", [Error]),
@@ -95,4 +91,3 @@ match(Topic, [Filter | Topics]) ->
 
 description() ->
     "ACL with LDAP".
-

apps/emqx_auth_ldap/src/emqx_auth_ldap.appup.src

@@ -0,0 +1,8 @@
+%% -*- mode: erlang -*-
+{VSN,
+  [{"4.3.0",
+    [{load_module,emqx_auth_ldap,brutal_purge,soft_purge,[]}]},
+   {<<".*">>,[]}],
+  [{"4.3.0",
+    [{load_module,emqx_auth_ldap,brutal_purge,soft_purge,[]}]},
+   {<<".*">>,[]}]}.