disable some lua functions

contract/vm.c

@@ -45,6 +45,31 @@ static void preloadModules(lua_State *L) {
 		luaopen_db(L);
 	}
 
+	if (vm_is_hardfork(L, 4)) {
+		lua_getglobal(L, "_G");
+		// disable getmetatable
+		lua_pushnil(L);
+		lua_setfield(L, -2, "getmetatable");
+		// disable setmetatable
+		lua_pushnil(L);
+		lua_setfield(L, -2, "setmetatable");
+		// disable rawget
+		lua_pushnil(L);
+		lua_setfield(L, -2, "rawget");
+		// disable rawset
+		lua_pushnil(L);
+		lua_setfield(L, -2, "rawset");
+		// disable rawequal
+		lua_pushnil(L);
+		lua_setfield(L, -2, "rawequal");
+		lua_pop(L, 1);
+		// disable string.dump
+		lua_getglobal(L, "string");
+		lua_pushnil(L);
+		lua_setfield(L, -2, "dump");
+		lua_pop(L, 1);
+	}
+
 #ifdef MEASURE
 	lua_register(L, "nsec", nsec);
 	luaopen_jit(L);

contract/vm_dummy/test_files/disabled-functions.lua

@@ -0,0 +1,46 @@
+
+function check_disabled_functions()
+
+  -- check the disabled modules
+  assert(os == nil, "os is available")
+  assert(io == nil, "io is available")
+  assert(debug == nil, "debug is available")
+  assert(jit == nil, "jit is available")
+  assert(ffi == nil, "ffi is available")
+  assert(coroutine == nil, "coroutine is available")
+  assert(package == nil, "package is available")
+
+  -- check the disabled functions
+  assert(collectgarbage == nil, "collectgarbage is available")
+  assert(gcinfo == nil, "gcinfo is available")
+  assert(module == nil, "module is available")
+  assert(require == nil, "require is available")
+  assert(dofile == nil, "dofile is available")
+  assert(load == nil, "load is available")
+  assert(loadlib == nil, "loadlib is available")
+  assert(loadfile == nil, "loadfile is available")
+  assert(loadstring == nil, "loadstring is available")
+  assert(print == nil, "print is available")
+  assert(getmetatable == nil, "getmetatable is available")
+  assert(setmetatable == nil, "setmetatable is available")
+  assert(rawget == nil, "rawget is available")
+  assert(rawset == nil, "rawset is available")
+  assert(rawequal == nil, "rawequal is available")
+  assert(string.dump == nil, "string.dump is available")
+
+  local success, result = pcall(function() newproxy() end)
+  assert(success == false and result:match(".* 'newproxy' not supported"), "newproxy is available")
+  local success, result = pcall(function() setfenv() end)
+  assert(success == false and result:match(".* 'setfenv' not supported"), "setfenv is available")
+  local success, result = pcall(function() getfenv() end)
+  assert(success == false and result:match(".* 'getfenv' not supported"), "getfenv is available")
+
+  -- make sure the tostring does not return a pointer
+  local tab = {}
+  assert(not tostring(type):match("0x[%x]+"), "tostring returns a pointer for function")
+  assert(not tostring(system):match("0x[%x]+"), "tostring returns a pointer for internal table")
+  assert(not tostring(tab):match("0x[%x]+"), "tostring returns a pointer for table")
+
+end
+
+abi.register(check_disabled_functions)

contract/vm_dummy/test_files/feature_isolation.lua

@@ -22,8 +22,10 @@ function override_functions()
     -- override contract.balance
     contract.balance = function() return "123" end
 
-    -- override the __add metamethod on bignum module
-    getmetatable(bignum.number(0)).__add = function(x,y) return x-y end
+    if getmetatable ~= nil then
+      -- override the __add metamethod on bignum module
+      getmetatable(bignum.number(0)).__add = function(x,y) return x-y end
+    end
 
 end
 
@@ -37,7 +39,9 @@ function check_local_overridden_functions()
     assert2(test_sender() == "overridden", "system.getSender() override failed")
     assert2(test_origin() == "overridden", "system.getOrigin() override failed")
     assert2(test_balance() == "123", "contract.balance() override failed")
-    assert2(test_bignum() == bignum.number(3), "metamethod override failed")
+    if getmetatable ~= nil then
+      assert2(test_bignum() == bignum.number(3), "metamethod override failed")
+    end
 
 end