From 6c52d5de1f4373f58b5c81616a7447404c1f3d65 Mon Sep 17 00:00:00 2001
From: firest <blankalupo@163.com>
Date: Tue, 1 Nov 2022 14:41:01 +0800
Subject: [PATCH] fix(bridge): Ensure that the node name is known

---
 apps/emqx/src/emqx_misc.erl              | 24 +++++++++++++++++-
 apps/emqx_bridge/src/emqx_bridge_api.erl | 32 ++++++++++++++++--------
 2 files changed, 45 insertions(+), 11 deletions(-)

diff --git a/apps/emqx/src/emqx_misc.erl b/apps/emqx/src/emqx_misc.erl
index 6833cbabb..54157da78 100644
--- a/apps/emqx/src/emqx_misc.erl
+++ b/apps/emqx/src/emqx_misc.erl
@@ -52,7 +52,9 @@
     explain_posix/1,
     pmap/2,
     pmap/3,
-    readable_error_msg/1
+    readable_error_msg/1,
+    safe_to_existing_atom/1,
+    safe_to_existing_atom/2
 ]).
 
 -export([
@@ -463,6 +465,18 @@ nolink_apply(Fun, Timeout) when is_function(Fun, 0) ->
         exit(timeout)
     end.
 
+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]);
+safe_to_existing_atom(Atom, _Encoding) when is_atom(Atom) ->
+    {ok, Atom};
+safe_to_existing_atom(_Any, _Encoding) ->
+    {error, invalid_type}.
+
 %%------------------------------------------------------------------------------
 %% Internal Functions
 %%------------------------------------------------------------------------------
@@ -533,6 +547,14 @@ readable_error_msg(Error) ->
             end
     end.
 
+try_to_existing_atom(Fun, Args) ->
+    try erlang:apply(Fun, Args) of
+        Atom ->
+            {ok, Atom}
+    catch
+        _:Reason -> {error, Reason}
+    end.
+
 -ifdef(TEST).
 -include_lib("eunit/include/eunit.hrl").
 
diff --git a/apps/emqx_bridge/src/emqx_bridge_api.erl b/apps/emqx_bridge/src/emqx_bridge_api.erl
index 37a42ab3d..66a9079f8 100644
--- a/apps/emqx_bridge/src/emqx_bridge_api.erl
+++ b/apps/emqx_bridge/src/emqx_bridge_api.erl
@@ -492,23 +492,16 @@ lookup_from_local_node(BridgeType, BridgeName) ->
             invalid ->
                 {400, error_msg('BAD_REQUEST', <<"invalid operation">>)};
             OperFunc ->
-                TargetNode = binary_to_atom(Node, utf8),
                 ConfMap = emqx:get_config([bridges, BridgeType, BridgeName]),
                 case maps:get(enable, ConfMap, false) of
                     false ->
                         {403,
                             error_msg(
-                                'FORBIDDEN_REQUEST', <<"forbidden operation: bridge disabled">>
+                                'FORBIDDEN_REQUEST',
+                                <<"forbidden operation: bridge disabled">>
                             )};
                     true ->
-                        case emqx_bridge_proto_v1:OperFunc(TargetNode, BridgeType, BridgeName) of
-                            ok ->
-                                {200};
-                            {error, timeout} ->
-                                {503, error_msg('SERVICE_UNAVAILABLE', <<"request timeout">>)};
-                            {error, Reason} ->
-                                {500, error_msg('INTERNAL_ERROR', Reason)}
-                        end
+                        call_operation(Node, OperFunc, BridgeType, BridgeName)
                 end
         end
     ).
@@ -707,3 +700,22 @@ bin(S) when is_atom(S) ->
     atom_to_binary(S, utf8);
 bin(S) when is_binary(S) ->
     S.
+
+call_operation(Node, OperFunc, BridgeType, BridgeName) ->
+    case emqx_misc:safe_to_existing_atom(Node, utf8) of
+        {ok, TargetNode} ->
+            case
+                emqx_bridge_proto_v1:OperFunc(
+                    TargetNode, BridgeType, BridgeName
+                )
+            of
+                ok ->
+                    {200};
+                {error, timeout} ->
+                    {503, error_msg('SERVICE_UNAVAILABLE', <<"request timeout">>)};
+                {error, Reason} ->
+                    {500, error_msg('INTERNAL_ERROR', Reason)}
+            end;
+        {error, _} ->
+            {400, error_msg('INVALID_NODE', <<"invalid node">>)}
+    end.