Instantly share code, notes, and snippets.

Embed
What would you like to do?
Workaround for Bouncycastle <= 1.60 faulty OpenPGP sub key generation (https://github.com/bcgit/bc-java/issues/381)
/*
* Copyright 2018 Paul Schaub.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.bouncycastle.bcpg.HashAlgorithmTags;
import org.bouncycastle.bcpg.PublicKeyPacket;
import org.bouncycastle.bcpg.PublicSubkeyPacket;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPPrivateKey;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPSecretKey;
import org.bouncycastle.openpgp.PGPSecretKeyRing;
import org.bouncycastle.openpgp.operator.PBESecretKeyDecryptor;
import org.bouncycastle.openpgp.operator.PBESecretKeyEncryptor;
import org.bouncycastle.openpgp.operator.PGPDigestCalculator;
import org.bouncycastle.openpgp.operator.bc.BcPGPDigestCalculatorProvider;
public class KeyRingSubKeyFix {
private static final Logger LOGGER = Logger.getLogger(KeyRingSubKeyFix.class.getName());
/**
* This method makes sure, that sub keys do consist of sub key packets.
* Bouncycastle versions up to and including 1.60 created {@link PGPSecretKeyRing}s which sub keys consisted of
* normal public key packets, which would result in lost keys when converting PGPSecretKeyRings to PGPPublicKeyRings.
*
* This method throws a {@link RuntimeException} of a {@link NoSuchFieldException} or {@link IllegalAccessException}.
*
* @see <a href="https://github.com/bcgit/bc-java/issues/381">Bouncycastle Java bug report #381</a>
*
* @param secretKeys possibly faulty PGPSecretKeyRing
* @param decryptor decryptor in case the keys are encrypted (can be null)
* @param encryptor encryptor to re-encrypt the keys in case they are encrypted (can be null)
*
* @return fixed PGPSecretKeyRing
*
* @throws PGPException in case we cannot dismantle or reassemble the key.
*/
public static PGPSecretKeyRing repairSubkeyPackets(PGPSecretKeyRing secretKeys,
PBESecretKeyDecryptor decryptor,
PBESecretKeyEncryptor encryptor)
throws PGPException {
PGPDigestCalculator calculator = new BcPGPDigestCalculatorProvider().get(HashAlgorithmTags.SHA1);
List<PGPSecretKey> _secretKeys = new ArrayList<>();
Iterator<PGPSecretKey> secretKeyIterator = secretKeys.iterator();
try {
while (secretKeyIterator.hasNext()) {
PGPSecretKey key = secretKeyIterator.next();
if (key.isMasterKey()) {
LOGGER.log(Level.INFO, Long.toHexString(key.getKeyID()) + " is master key. Skip.");
_secretKeys.add(key);
continue;
}
PGPSecretKey secSubKey = key;
PGPPublicKey pubSubKey = secSubKey.getPublicKey();
// check for public key packet type
Field publicPk = pubSubKey.getClass().getDeclaredField("publicPk");
publicPk.setAccessible(true);
PublicKeyPacket keyPacket = (PublicKeyPacket) publicPk.get(pubSubKey);
if (keyPacket instanceof PublicSubkeyPacket) {
// Sub key is already sub key
_secretKeys.add(secSubKey);
continue;
}
// Sub key is normal key -> fix
LOGGER.log(Level.INFO, "Subkey " + Long.toHexString(secSubKey.getKeyID()) + " does not have a subkey key packet. Convert it...");
keyPacket = new PublicSubkeyPacket(pubSubKey.getAlgorithm(), pubSubKey.getCreationTime(), keyPacket.getKey());
publicPk.set(pubSubKey, keyPacket);
PGPPrivateKey privateKey = secSubKey.extractPrivateKey(decryptor);
PGPSecretKey secretKey = new PGPSecretKey(privateKey, pubSubKey, calculator, false, encryptor);
_secretKeys.add(secretKey);
}
return new PGPSecretKeyRing(_secretKeys);
} catch (NoSuchFieldException | IllegalAccessException e) {
throw new RuntimeException("Cannot apply fix due to an error while using reflections.", e);
}
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment