From c12805ecac6f1a041037afbf720f1ae4a33f4c43 Mon Sep 17 00:00:00 2001
From: "nstbayless@gmail.com" <nstbayless@gmail.com>
Date: Thu, 1 Oct 2026 17:40:46 -0700
Subject: [PATCH] remove some lua functions that break determinism or can be
 harmful

---
 src/config.c   |  4 +--
 src/lua_base.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 69 insertions(+), 3 deletions(-)

diff --git a/src/config.c b/src/config.c
index dce8488627..5301cf1680 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1254,8 +1254,8 @@ long get_rid(const struct NamedCommand *desc, const char *itmname)
   }
   if (strcasecmp("RANDOM", itmname) == 0)
   {
-      i = (rand() % i);
-      return desc[i].num;
+      int32_t idx = (int32_t)LbRandomSeries((uint32_t)i, &game.action_random_seed, __func__, __LINE__);
+      return desc[idx].num;
   }
   return -1;
 }
diff --git a/src/lua_base.c b/src/lua_base.c
index 88ef342bb6..df2b3a9e53 100644
--- a/src/lua_base.c
+++ b/src/lua_base.c
@@ -38,8 +38,51 @@ static int lua_disabled_os_function(lua_State *L)
 }
 
 
+static void lua_blacklist(lua_State *L, const char *libname, const char *name)
+{
+    lua_getglobal(L, libname);
+    if (!lua_istable(L, -1)) {
+        lua_pop(L, 1);
+        return;
+    }
+    lua_pushnil(L);
+    lua_setfield(L, -2, name);
+    lua_pop(L, 1);
+}
+
+static void lua_whitelist(lua_State *L, const char *libname, const char *keep)
+{
+    lua_getglobal(L, libname);
+    if (!lua_istable(L, -1)) {
+        lua_pop(L, 1);
+        return;
+    }
+    int t = lua_gettop(L);
+    lua_pushnil(L);
+    while (lua_next(L, t) != 0) {
+        if (lua_type(L, -2) == LUA_TSTRING) {
+            const char *key = lua_tostring(L, -2);
+            if (strcmp(key, keep) != 0) {
+                lua_pushnil(L);
+                lua_setfield(L, t, key);
+            }
+        }
+        lua_pop(L, 1);
+    }
+    lua_pop(L, 1);
+}
+
+// Remove Lua functions which can break the sandbox/determinism
 static void disable_lua_functions(lua_State *L)
 {
+    // TODO - remove/replace these
+    lua_whitelist(L, "io", "open");
+
+    // TODO - remove/replace these
+    lua_whitelist(L, "os", "remove");
+
+    lua_blacklist(L, "package", "loadlib");
+
     if (game.game_kind != GKind_MultiGame) {
         return;
     }
@@ -293,11 +336,34 @@ static void open_lua_script_for_mod_all(lua_State* L, LevelNumber lvnum)
 /* @comment
  *     The loading items of open_lua_script and open_lua_script_for_mod need to be consistent.
  */
+static void open_lua_standard_libraries(lua_State *L)
+{
+    static const luaL_Reg stdlib[] = {
+        {"",               luaopen_base},
+        {LUA_TABLIBNAME,   luaopen_table},
+        {LUA_IOLIBNAME,    luaopen_io},
+        {LUA_OSLIBNAME,    luaopen_os},
+        {LUA_STRLIBNAME,   luaopen_string},
+        {LUA_MATHLIBNAME,  luaopen_math},
+        {LUA_DBLIBNAME,    luaopen_debug},
+        {LUA_LOADLIBNAME,  luaopen_package},
+        {LUA_BITLIBNAME,   luaopen_bit},
+        // {LUA_JITLIBNAME,   luaopen_jit},
+        // {LUA_FFILIBNAME,   luaopen_ffi},
+        {NULL, NULL}
+    };
+    for (const luaL_Reg *lib = stdlib; lib->func != NULL; lib++) {
+        lua_pushcfunction(L, lib->func);
+        lua_pushstring(L, lib->name);
+        lua_call(L, 1, 0);
+    }
+}
+
 TbBool open_lua_script(LevelNumber lvnum)
 {
     Lvl_script = luaL_newstate();
 
-    luaL_openlibs(Lvl_script);
+    open_lua_standard_libraries(Lvl_script);
     disable_lua_functions(Lvl_script);
 
     lua_set_random_seed(game.action_random_seed);