undefect. CWE-407 — 63 sites patched across 27 ecosystems

Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com

Patches, unit tests, benchmarks, whitepaper, and outreach briefs.
Public domain — no copyright claimed. Use freely.

test/jdk/java/lang/reflect/Proxy/HiddenProxyInterface.java

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+/*
+ * Copyright (c) 2020, 2026, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8250219
+ * @run junit HiddenProxyInterface
+ */
+
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.*;
+import org.junit.jupiter.api.Test;
+
+public class HiddenProxyInterface {
+    private static final Path CLASSES_DIR = Paths.get(System.getProperty("test.classes"));
+
+    interface Intf {
+        void m();
+    }
+
+    @Test
+    public void testHiddenInterface() throws Exception {
+        Path classFile = CLASSES_DIR.resolve("HiddenProxyInterface$Intf.class");
+        byte[] bytes = Files.readAllBytes(classFile);
+        Class<?> hiddenIntf = MethodHandles.lookup().defineHiddenClass(bytes, false).lookupClass();
+        assertThrows(IllegalArgumentException.class, () -> Proxy.newProxyInstance(
+                HiddenProxyInterface.class.getClassLoader(),
+                new Class<?>[]{ hiddenIntf },
+                new InvocationHandler() {
+                    @Override
+                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+                        return null;
+                    }
+                }));
+    }
+}