From: Vsevolod Stakhov <vsevolod@rspamd.com>
Date: Sat, 6 Dec 2025 11:09:03 +0000 (+0000)
Subject: [Fix] Improve loadstring error handling for Lua 5.4 compatibility
X-Git-Tag: 3.14.2~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=738edf0cb72b43e37671bd37537bfc1065d0058c;p=thirdparty%2Frspamd.git

[Fix] Improve loadstring error handling for Lua 5.4 compatibility

Ensure loadstring results are checked for nil (syntax errors) before
passing to pcall. This prevents errors when running with Lua 5.4
compatibility where load behavior differs slightly or when handling
invalid Lua chunks.
---

diff --git a/lualib/lua_dkim_tools.lua b/lualib/lua_dkim_tools.lua
index 1942f4c2d8..be446f8bc0 100644
--- a/lualib/lua_dkim_tools.lua
+++ b/lualib/lua_dkim_tools.lua
@@ -385,7 +385,15 @@ local function prepare_dkim_signing(N, task, settings)
       if type(settings.use_domain_custom) == 'string' then
         -- Load custom function
         local loadstring = loadstring or load
-        local ret, res_or_err = pcall(loadstring(settings.use_domain_custom))
+        local chunk, err = loadstring(settings.use_domain_custom)
+        local ret, res_or_err
+        if chunk then
+          ret, res_or_err = pcall(chunk)
+        else
+          ret = false
+          res_or_err = err
+        end
+
         if ret then
           if type(res_or_err) == 'function' then
             settings.use_domain_custom = res_or_err
diff --git a/lualib/lua_util.lua b/lualib/lua_util.lua
index 091bcc8ceb..06571e638d 100644
--- a/lualib/lua_util.lua
+++ b/lualib/lua_util.lua
@@ -1529,7 +1529,12 @@ exports.callback_from_string = function(s)
     inp = 'return function(...)\n' .. s .. '; end'
   end
 
-  local ret, res_or_err = pcall(loadstring(inp))
+  local chunk, err = loadstring(inp)
+  if not chunk then
+    return false, err
+  end
+
+  local ret, res_or_err = pcall(chunk)
 
   if not ret or type(res_or_err) ~= 'function' then
     return false, res_or_err
diff --git a/src/plugins/lua/clickhouse.lua b/src/plugins/lua/clickhouse.lua
index 16a8ad4ec1..2811206b90 100644
--- a/src/plugins/lua/clickhouse.lua
+++ b/src/plugins/lua/clickhouse.lua
@@ -1364,7 +1364,14 @@ if opts then
         if rule.schema and rule.first_row and rule.get_row then
           local first_row, get_row
           local loadstring = loadstring or load
-          local ret, res_or_err = pcall(loadstring(rule.first_row))
+          local ret, res_or_err
+          local chunk, err = loadstring(rule.first_row)
+          if chunk then
+            ret, res_or_err = pcall(chunk)
+          else
+            ret = false
+            res_or_err = err
+          end
 
           if not ret or type(res_or_err) ~= 'function' then
             rspamd_logger.errx(rspamd_config, 'invalid first_row (%s) - must be a function',
@@ -1373,7 +1380,13 @@ if opts then
             first_row = res_or_err
           end
 
-          ret, res_or_err = pcall(loadstring(rule.get_row))
+          chunk, err = loadstring(rule.get_row)
+          if chunk then
+            ret, res_or_err = pcall(chunk)
+          else
+            ret = false
+            res_or_err = err
+          end
 
           if not ret or type(res_or_err) ~= 'function' then
             rspamd_logger.errx(rspamd_config,