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package org.sufficientlysecure.keychain.pgp;
import org.spongycastle.bcpg.HashAlgorithmTags;
import org.spongycastle.bcpg.S2K;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPPrivateKey;
import org.spongycastle.openpgp.PGPPublicKey;
import org.spongycastle.openpgp.PGPPublicKeyRing;
import org.spongycastle.openpgp.PGPSecretKey;
import org.spongycastle.openpgp.PGPSignature;
import org.spongycastle.openpgp.PGPSignatureGenerator;
import org.spongycastle.openpgp.PGPSignatureSubpacketGenerator;
import org.spongycastle.openpgp.PGPSignatureSubpacketVector;
import org.spongycastle.openpgp.PGPUtil;
import org.spongycastle.openpgp.operator.PBESecretKeyDecryptor;
import org.spongycastle.openpgp.operator.PGPContentSignerBuilder;
import org.spongycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
import org.spongycastle.openpgp.operator.jcajce.JcaPGPContentSignerBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcePBESecretKeyDecryptorBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder;
import org.spongycastle.openpgp.operator.jcajce.NfcSyncPGPContentSignerBuilder;
import org.sufficientlysecure.keychain.Constants;
import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralMsgIdException;
import org.sufficientlysecure.keychain.util.IterableIterator;
import org.sufficientlysecure.keychain.util.Log;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SignatureException;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
/** Wrapper for a PGPSecretKey.
*
* This object can only be obtained from a WrappedSecretKeyRing, and stores a
* back reference to its parent.
*
* This class represents known secret keys which are stored in the database.
* All "crypto operations using a known secret key" should be implemented in
* this class, to ensure on type level that these operations are performed on
* properly imported secret keys only.
*
*/
public class CanonicalizedSecretKey extends CanonicalizedPublicKey {
private final PGPSecretKey mSecretKey;
private PGPPrivateKey mPrivateKey = null;
private int mPrivateKeyState = PRIVATE_KEY_STATE_LOCKED;
private static int PRIVATE_KEY_STATE_LOCKED = 0;
private static int PRIVATE_KEY_STATE_UNLOCKED = 1;
private static int PRIVATE_KEY_STATE_DIVERT_TO_CARD = 2;
CanonicalizedSecretKey(CanonicalizedSecretKeyRing ring, PGPSecretKey key) {
super(ring, key.getPublicKey());
mSecretKey = key;
}
public CanonicalizedSecretKeyRing getRing() {
return (CanonicalizedSecretKeyRing) mRing;
}
/**
* Returns true on right passphrase
*/
public boolean unlock(String passphrase) throws PgpGeneralException {
// handle keys on OpenPGP cards like they were unlocked
if (mSecretKey.getS2K().getType() == S2K.GNU_DUMMY_S2K
&& mSecretKey.getS2K().getProtectionMode() == S2K.GNU_PROTECTION_MODE_DIVERT_TO_CARD) {
mPrivateKeyState = PRIVATE_KEY_STATE_DIVERT_TO_CARD;
return true;
}
// try to extract keys using the passphrase
try {
PBESecretKeyDecryptor keyDecryptor = new JcePBESecretKeyDecryptorBuilder().setProvider(
Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.toCharArray());
mPrivateKey = mSecretKey.extractPrivateKey(keyDecryptor);
mPrivateKeyState = PRIVATE_KEY_STATE_UNLOCKED;
} catch (PGPException e) {
return false;
}
if(mPrivateKey == null) {
throw new PgpGeneralException("error extracting key");
}
return true;
}
// TODO: just a hack currently
public LinkedList<Integer> getSupportedHashAlgorithms() {
LinkedList<Integer> supported = new LinkedList<Integer>();
if (mPrivateKeyState == PRIVATE_KEY_STATE_DIVERT_TO_CARD) {
// TODO: only works with SHA256 ?!
supported.add(HashAlgorithmTags.SHA256);
} else {
supported.add(HashAlgorithmTags.MD5);
supported.add(HashAlgorithmTags.RIPEMD160);
supported.add(HashAlgorithmTags.SHA1);
supported.add(HashAlgorithmTags.SHA224);
supported.add(HashAlgorithmTags.SHA256);
supported.add(HashAlgorithmTags.SHA384);
supported.add(HashAlgorithmTags.SHA512); // preferred is latest
}
return supported;
}
public PGPSignatureGenerator getSignatureGenerator(int hashAlgo, boolean cleartext,
byte[] nfcSignedHash, Date nfcCreationTimestamp)
throws PgpGeneralException {
if (mPrivateKeyState == PRIVATE_KEY_STATE_LOCKED) {
throw new PrivateKeyNotUnlockedException();
}
PGPContentSignerBuilder contentSignerBuilder;
if (mPrivateKeyState == PRIVATE_KEY_STATE_DIVERT_TO_CARD) {
// to sign using nfc PgpSignEncrypt is executed two times.
// the first time it stops to return the PendingIntent for nfc connection and signing the hash
// the second time the signed hash is used.
// to get the same hash we cache the timestamp for the second round!
if (nfcCreationTimestamp == null) {
nfcCreationTimestamp = new Date();
}
// use synchronous "NFC based" SignerBuilder
contentSignerBuilder = new NfcSyncPGPContentSignerBuilder(
mSecretKey.getPublicKey().getAlgorithm(), hashAlgo,
mSecretKey.getKeyID(), nfcSignedHash, nfcCreationTimestamp)
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
Log.d(Constants.TAG, "mSecretKey.getKeyID() "+ PgpKeyHelper.convertKeyIdToHex(mSecretKey.getKeyID()));
} else {
// content signer based on signing key algorithm and chosen hash algorithm
contentSignerBuilder = new JcaPGPContentSignerBuilder(
mSecretKey.getPublicKey().getAlgorithm(), hashAlgo)
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
}
int signatureType;
if (cleartext) {
// for sign-only ascii text
signatureType = PGPSignature.CANONICAL_TEXT_DOCUMENT;
} else {
signatureType = PGPSignature.BINARY_DOCUMENT;
}
try {
PGPSignatureGenerator signatureGenerator = new PGPSignatureGenerator(contentSignerBuilder);
signatureGenerator.init(signatureType, mPrivateKey);
PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
spGen.setSignerUserID(false, mRing.getPrimaryUserIdWithFallback());
if (nfcCreationTimestamp != null) {
spGen.setSignatureCreationTime(false, nfcCreationTimestamp);
Log.d(Constants.TAG, "For NFC: set sig creation time to " + nfcCreationTimestamp);
}
signatureGenerator.setHashedSubpackets(spGen.generate());
return signatureGenerator;
} catch(PGPException e) {
// TODO: simply throw PGPException!
throw new PgpGeneralException("Error initializing signature!", e);
}
}
public PublicKeyDataDecryptorFactory getDecryptorFactory() {
// TODO: divert to card missing
if (mPrivateKeyState != PRIVATE_KEY_STATE_UNLOCKED) {
throw new PrivateKeyNotUnlockedException();
}
return new JcePublicKeyDataDecryptorFactoryBuilder()
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(mPrivateKey);
}
/**
* Certify the given pubkeyid with the given masterkeyid.
*
* @param publicKeyRing Keyring to add certification to.
* @param userIds User IDs to certify, must not be null or empty
* @return A keyring with added certifications
*/
public UncachedKeyRing certifyUserIds(CanonicalizedPublicKeyRing publicKeyRing, List<String> userIds)
throws PgpGeneralMsgIdException, NoSuchAlgorithmException, NoSuchProviderException,
PGPException, SignatureException {
// TODO: divert to card missing
if (mPrivateKeyState != PRIVATE_KEY_STATE_UNLOCKED) {
throw new PrivateKeyNotUnlockedException();
}
// create a signatureGenerator from the supplied masterKeyId and passphrase
PGPSignatureGenerator signatureGenerator;
{
// TODO: SHA256 fixed?
JcaPGPContentSignerBuilder contentSignerBuilder = new JcaPGPContentSignerBuilder(
mSecretKey.getPublicKey().getAlgorithm(), PGPUtil.SHA256)
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
signatureGenerator = new PGPSignatureGenerator(contentSignerBuilder);
signatureGenerator.init(PGPSignature.DEFAULT_CERTIFICATION, mPrivateKey);
}
{ // supply signatureGenerator with a SubpacketVector
PGPSignatureSubpacketGenerator spGen = new PGPSignatureSubpacketGenerator();
PGPSignatureSubpacketVector packetVector = spGen.generate();
signatureGenerator.setHashedSubpackets(packetVector);
}
// get the master subkey (which we certify for)
PGPPublicKey publicKey = publicKeyRing.getPublicKey().getPublicKey();
// fetch public key ring, add the certification and return it
for (String userId : new IterableIterator<String>(userIds.iterator())) {
PGPSignature sig = signatureGenerator.generateCertification(userId, publicKey);
publicKey = PGPPublicKey.addCertification(publicKey, userId, sig);
}
PGPPublicKeyRing ring = PGPPublicKeyRing.insertPublicKey(publicKeyRing.getRing(), publicKey);
return new UncachedKeyRing(ring);
}
static class PrivateKeyNotUnlockedException extends RuntimeException {
// this exception is a programming error which happens when an operation which requires
// the private key is called without a previous call to unlock()
}
public UncachedSecretKey getUncached() {
return new UncachedSecretKey(mSecretKey);
}
// HACK
public PGPSecretKey getSecretKey() {
return mSecretKey;
}
}
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