Lua: Sandbox by default (whitelisted functions); Disable inline scripts for now; Add more checks for security reasons (#7136)

https://github.com/XTLS/Xray-core/pull/7136#issuecomment-6158632073
https://github.com/XTLS/Xray-core/pull/7136#issuecomment-6170831601
https://github.com/XTLS/Xray-core/pull/7136#issuecomment-6184362904

common/lua/geodata_security_watchdog_test.go

@@ -0,0 +1,19 @@
+// DO NOT EDIT. Regression test for app/geodata's luaGuardHeader.
+
+package lua
+
+import (
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/yuin/gopher-lua/parse"
+)
+
+func TestGeodataLuaGuard(t *testing.T) {
+	_, err := parse.Parse(strings.NewReader("\x12\x01\x00function HandleRoute() end"), "geodata")
+	var syntaxErr *parse.Error
+	if !errors.As(err, &syntaxErr) || syntaxErr.Pos.Line != 1 || syntaxErr.Pos.Column != 1 {
+		t.Fatalf("want Lua rejection at the first byte, got %v", err)
+	}
+}