From 490065f3ed3dd9377a740ad6fcbc441a658889dd Mon Sep 17 00:00:00 2001
From: Albert Krewinkel <albert@zeitkraut.de>
Date: Tue, 26 Jan 2021 14:19:30 +0100
Subject: Lua: always load built-in Lua scripts from default data-dir

The Lua modules `pandoc` and `pandoc.List` are now always loaded from the
system's default data directory. Loading from a different directory by
overriding the default path, e.g. via `--data-dir`, is no longer supported to
avoid unexpected behavior and to address security concerns.
---
 src/Text/Pandoc/Lua/Init.hs | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

(limited to 'src/Text/Pandoc/Lua/Init.hs')

diff --git a/src/Text/Pandoc/Lua/Init.hs b/src/Text/Pandoc/Lua/Init.hs
index 0a5ce85cb..baa6f0295 100644
--- a/src/Text/Pandoc/Lua/Init.hs
+++ b/src/Text/Pandoc/Lua/Init.hs
@@ -12,17 +12,18 @@ module Text.Pandoc.Lua.Init
   ( runLua
   ) where
 
+import Control.Monad (when)
 import Control.Monad.Catch (try)
 import Control.Monad.Trans (MonadIO (..))
 import Data.Data (Data, dataTypeConstrs, dataTypeOf, showConstr)
 import Foreign.Lua (Lua)
 import GHC.IO.Encoding (getForeignEncoding, setForeignEncoding, utf8)
+import Text.Pandoc.Class.PandocMonad (readDataFile)
 import Text.Pandoc.Class.PandocIO (PandocIO)
 import Text.Pandoc.Error (PandocError)
 import Text.Pandoc.Lua.Packages (installPandocPackageSearcher)
-import Text.Pandoc.Lua.PandocLua (PandocLua, liftPandocLua,
-                                  loadScriptFromDataDir, runPandocLua)
-
+import Text.Pandoc.Lua.PandocLua (PandocLua, liftPandocLua, runPandocLua)
+import Text.Pandoc.Lua.Util (throwTopMessageAsError')
 import qualified Foreign.Lua as Lua
 import qualified Text.Pandoc.Definition as Pandoc
 import qualified Text.Pandoc.Lua.Module.Pandoc as ModulePandoc
@@ -44,7 +45,7 @@ initLuaState = do
   liftPandocLua Lua.openlibs
   installPandocPackageSearcher
   initPandocModule
-  loadScriptFromDataDir "init.lua"
+  loadInitScript "init.lua"
  where
   initPandocModule :: PandocLua ()
   initPandocModule = do
@@ -61,6 +62,15 @@ initLuaState = do
     -- assign module to global variable
     liftPandocLua $ Lua.setglobal "pandoc"
 
+  loadInitScript :: FilePath -> PandocLua ()
+  loadInitScript scriptFile = do
+    script <- readDataFile scriptFile
+    status <- liftPandocLua $ Lua.dostring script
+    when (status /= Lua.OK) . liftPandocLua $
+      throwTopMessageAsError'
+      (("Couldn't load '" ++ scriptFile ++ "'.\n") ++)
+
+
 -- | AST elements are marshaled via normal constructor functions in the
 -- @pandoc@ module. However, accessing Lua globals from Haskell is
 -- expensive (due to error handling). Accessing the Lua registry is much
-- 
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