ibiubcsevfuqbeksesgfvyukb

src/clear_globals.lua

@@ -0,0 +1,23 @@
+local clear =  {}
+
+function table_contains(tbl, x)
+    found = false
+    for _, v in pairs(tbl) do
+        if v == x then 
+            found = true 
+        end
+    end
+    return found
+end
+
+WHITELIST = {"_G", "WHITELIST", "clearAllGlobals", "print", "k", 
+            "v", "pairs", "table_contains", "string", "table", 
+            "tonumber", "tostring", "type", "f"}
+
+function clear.clearAllGlobals()
+    for k, v in pairs(_G) do
+        if not table_contains(WHITELIST, tostring(k)) then _G[k] = nil end;
+    end
+end
+
+return clear

src/luajit.c

@@ -624,20 +624,19 @@ int do_something()
         : "cc");
     }
     
-return x+y;
-}
+    return x+y;
+  }
 }
 
 #define C_FUNCTIONS_N 10
 
 struct global_var_t {
-char input_buffer[LUA_MAXINPUT];
-int (*c_functions[C_FUNCTIONS_N]) (void);
+  char input_buffer[LUA_MAXINPUT];
+  int (*c_functions[C_FUNCTIONS_N]) (void);
 } global = {{},{random_digit,get_time,do_something,0,0,0,0,0,0,0}};
 
 static int pushline(lua_State *L, int firstline)
 {
-  
   write_prompt(L, firstline);
   if (fgets(global.input_buffer, LUA_MAXINPUT, stdin)) {
     size_t len = strlen(global.input_buffer);
@@ -672,13 +671,13 @@ const char *lua = "local ffi = require(\"ffi\")\n"
                   "ffi.cdef[[\n"
                   "int call_c_function(int);\n"
                   "]]\n"
-                  "f = ffi.C.call_c_function\n";
-
+                  "f = ffi.C.call_c_function\n"
+                  "local clear = require(\"clear_globals\")\n"
+                  "clear.clearAllGlobals()\n";
 
 char flag[0x40] = {0};
 FILE *flagfile;
 
-
 int main(int argc, char **argv)
 {
   flagfile = popen("/bin/get_flag", "r");
@@ -701,6 +700,8 @@ int main(int argc, char **argv)
       printf("err: %s\n", lua_tostring(L, -1));
   }
 
+
+    
   smain.argc = argc;
   smain.argv = argv;