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/*
* Copyright (c) 2017, 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 8183591
* @summary Test decoding of DER length fields containing Integer.MAX_VALUE
* @run main TestMaxLengthDER
*/
import java.io.*;
import java.math.*;
import java.security.*;
import java.security.spec.*;
public class TestMaxLengthDER {
public static void main(String[] args) throws Exception {
String message = "Message";
Signature sig = Signature.getInstance("SHA256withDSA");
KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");
SecureRandom rnd = new SecureRandom();
rnd.setSeed(1);
kpg.initialize(2048, rnd);
KeyPair kp = kpg.generateKeyPair();
sig.initSign(kp.getPrivate());
sig.update(message.getBytes());
byte[] sigData = sig.sign();
// Set the length of the second integer to Integer.MAX_VALUE
// First copy all the signature data to the correct location
int lengthPos = sigData[3] + 5;
byte[] modifiedSigData = new byte[sigData.length + 4];
System.arraycopy(sigData, 0, modifiedSigData, 0, lengthPos);
System.arraycopy(sigData, lengthPos + 1, modifiedSigData,
lengthPos + 5, sigData.length - (lengthPos + 1));
// Increase the length (in bytes) of the sequence to account for
// the larger length field
modifiedSigData[1] += 4;
// Modify the length field
modifiedSigData[lengthPos] = (byte) 0x84;
modifiedSigData[lengthPos + 1] = (byte) 0x7F;
modifiedSigData[lengthPos + 2] = (byte) 0xFF;
modifiedSigData[lengthPos + 3] = (byte) 0xFF;
modifiedSigData[lengthPos + 4] = (byte) 0xFF;
sig.initVerify(kp.getPublic());
sig.update(message.getBytes());
try {
sig.verify(modifiedSigData);
throw new RuntimeException("No exception on misencoded signature");
} catch (SignatureException ex) {
if (ex.getCause() instanceof EOFException) {
// this is expected
} else {
throw ex;
}
}
}
}
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