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package org.sufficientlysecure.keychain.pgp;
import org.spongycastle.bcpg.ArmoredOutputStream;
import org.spongycastle.bcpg.SignatureSubpacketTags;
import org.spongycastle.bcpg.sig.KeyFlags;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPPublicKey;
import org.spongycastle.openpgp.PGPPublicKeyRing;
import org.spongycastle.openpgp.PGPSignature;
import org.spongycastle.openpgp.PGPSignatureList;
import org.spongycastle.openpgp.PGPSignatureSubpacketVector;
import org.spongycastle.openpgp.operator.jcajce.JcaPGPContentVerifierBuilderProvider;
import org.sufficientlysecure.keychain.Constants;
import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
import org.sufficientlysecure.keychain.util.IterableIterator;
import java.io.IOException;
import java.security.SignatureException;
import java.util.Arrays;
import java.util.Date;
import java.util.Iterator;
public class CachedPublicKeyRing extends CachedKeyRing {
private PGPPublicKeyRing mRing;
private final byte[] mPubKey;
public CachedPublicKeyRing(long masterKeyId, int keySize, boolean isRevoked,
boolean canCertify, long creation, long expiry, int algorithm,
byte[] fingerprint, String userId, int verified, boolean hasSecret,
byte[] pubkey)
{
super(masterKeyId, keySize, isRevoked, canCertify, creation, expiry,
algorithm, fingerprint, userId, verified, hasSecret);
mPubKey = pubkey;
}
private PGPPublicKeyRing getRing() {
if(mRing == null) {
mRing = (PGPPublicKeyRing) PgpConversionHelper.BytesToPGPKeyRing(mPubKey);
}
return mRing;
}
public void encode(ArmoredOutputStream stream) throws IOException {
getRing().encode(stream);
}
public CachedPublicKey getSubkey(long id) {
return new CachedPublicKey(this, getRing().getPublicKey(id));
}
public CachedPublicKey getFirstEncryptSubkey() throws PgpGeneralException {
// only return master key if no other encryption key is available
PGPPublicKey masterKey = null;
for (PGPPublicKey key : new IterableIterator<PGPPublicKey>(getRing().getPublicKeys())) {
if (key.isRevoked() || !isEncryptionKey(key) || isExpired(key)) {
continue;
}
if (key.isMasterKey()) {
masterKey = key;
} else {
return new CachedPublicKey(this, key);
}
}
if(masterKey == null) {
// TODO proper exception
throw new PgpGeneralException("key not found");
}
return new CachedPublicKey(this, masterKey);
}
public boolean verifySubkeyBinding(CachedPublicKey cachedSubkey) {
boolean validSubkeyBinding = false;
boolean validTempSubkeyBinding = false;
boolean validPrimaryKeyBinding = false;
PGPPublicKey masterKey = getRing().getPublicKey();
PGPPublicKey subKey = cachedSubkey.getKey();
// Is this the master key? Match automatically, then.
if(Arrays.equals(masterKey.getFingerprint(), subKey.getFingerprint())) {
return true;
}
JcaPGPContentVerifierBuilderProvider contentVerifierBuilderProvider =
new JcaPGPContentVerifierBuilderProvider()
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
Iterator<PGPSignature> itr = subKey.getSignatures();
while (itr.hasNext()) { //what does gpg do if the subkey binding is wrong?
//gpg has an invalid subkey binding error on key import I think, but doesn't shout
//about keys without subkey signing. Can't get it to import a slightly broken one
//either, so we will err on bad subkey binding here.
PGPSignature sig = itr.next();
if (sig.getKeyID() == masterKey.getKeyID() &&
sig.getSignatureType() == PGPSignature.SUBKEY_BINDING) {
//check and if ok, check primary key binding.
try {
sig.init(contentVerifierBuilderProvider, masterKey);
validTempSubkeyBinding = sig.verifyCertification(masterKey, subKey);
} catch (PGPException e) {
continue;
} catch (SignatureException e) {
continue;
}
if (validTempSubkeyBinding) {
validSubkeyBinding = true;
}
if (validTempSubkeyBinding) {
validPrimaryKeyBinding = verifyPrimaryKeyBinding(sig.getUnhashedSubPackets(),
masterKey, subKey);
if (validPrimaryKeyBinding) {
break;
}
validPrimaryKeyBinding = verifyPrimaryKeyBinding(sig.getHashedSubPackets(),
masterKey, subKey);
if (validPrimaryKeyBinding) {
break;
}
}
}
}
return validSubkeyBinding && validPrimaryKeyBinding;
}
static boolean isEncryptionKey(PGPPublicKey key) {
if (!key.isEncryptionKey()) {
return false;
}
if (key.getVersion() <= 3) {
// this must be true now
return key.isEncryptionKey();
}
// special cases
if (key.getAlgorithm() == PGPPublicKey.ELGAMAL_ENCRYPT) {
return true;
}
if (key.getAlgorithm() == PGPPublicKey.RSA_ENCRYPT) {
return true;
}
for (PGPSignature sig : new IterableIterator<PGPSignature>(key.getSignatures())) {
if (key.isMasterKey() && sig.getKeyID() != key.getKeyID()) {
continue;
}
PGPSignatureSubpacketVector hashed = sig.getHashedSubPackets();
if (hashed != null
&& (hashed.getKeyFlags() & (KeyFlags.ENCRYPT_COMMS | KeyFlags.ENCRYPT_STORAGE)) != 0) {
return true;
}
PGPSignatureSubpacketVector unhashed = sig.getUnhashedSubPackets();
if (unhashed != null
&& (unhashed.getKeyFlags() & (KeyFlags.ENCRYPT_COMMS | KeyFlags.ENCRYPT_STORAGE)) != 0) {
return true;
}
}
return false;
}
static boolean isExpired(PGPPublicKey key) {
Date creationDate = key.getCreationTime();
Date expiryDate = key.getValidSeconds() > 0
? new Date(creationDate.getTime() + key.getValidSeconds() * 1000) : null;
Date now = new Date();
return creationDate.after(now) || (expiryDate != null && expiryDate.before(now));
}
static boolean verifyPrimaryKeyBinding(PGPSignatureSubpacketVector pkts,
PGPPublicKey masterPublicKey,
PGPPublicKey signingPublicKey) {
boolean validPrimaryKeyBinding = false;
JcaPGPContentVerifierBuilderProvider contentVerifierBuilderProvider =
new JcaPGPContentVerifierBuilderProvider()
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
PGPSignatureList eSigList;
if (pkts.hasSubpacket(SignatureSubpacketTags.EMBEDDED_SIGNATURE)) {
try {
eSigList = pkts.getEmbeddedSignatures();
} catch (IOException e) {
return false;
} catch (PGPException e) {
return false;
}
for (int j = 0; j < eSigList.size(); ++j) {
PGPSignature emSig = eSigList.get(j);
if (emSig.getSignatureType() == PGPSignature.PRIMARYKEY_BINDING) {
try {
emSig.init(contentVerifierBuilderProvider, signingPublicKey);
validPrimaryKeyBinding = emSig.verifyCertification(masterPublicKey, signingPublicKey);
if (validPrimaryKeyBinding) {
break;
}
} catch (PGPException e) {
continue;
} catch (SignatureException e) {
continue;
}
}
}
}
return validPrimaryKeyBinding;
}
}
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