ModifyStaticFields.java

/*
 * Copyright (c) 2000, 2019, 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 4334623
 * @summary Verify that serialPersistentFields cannot be used to cause
 *          deserialization to set the value of a static field.
 */

import java.io.*;

public class ModifyStaticFields implements Serializable {
    private static final long serialVersionUID = 1L;

    private static final ObjectStreamField[] serialPersistentFields =
        new ObjectStreamField[] { new ObjectStreamField("str", String.class) };

    static String str = "foo";

    public static void main(String[] args) throws Exception {
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        ObjectOutputStream oout = new ObjectOutputStream(bout);
        oout.writeObject(new ModifyStaticFields());
        oout.close();

        String origStr = str;
        ObjectInputStream oin = new ObjectInputStream(
            new ByteArrayInputStream(bout.toByteArray()));
        oin.readObject();
        if (str != origStr) {
            throw new Error("deserialization modified static field");
        }
    }

    private void writeObject(ObjectOutputStream out) throws IOException {
        ObjectOutputStream.PutField pf = out.putFields();
        pf.put("str", "bar");
        out.writeFields();
    }
}