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package de.pixart.messenger.crypto.axolotl;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;
import org.whispersystems.libsignal.DuplicateMessageException;
import org.whispersystems.libsignal.IdentityKey;
import org.whispersystems.libsignal.InvalidKeyException;
import org.whispersystems.libsignal.InvalidKeyIdException;
import org.whispersystems.libsignal.InvalidMessageException;
import org.whispersystems.libsignal.InvalidVersionException;
import org.whispersystems.libsignal.LegacyMessageException;
import org.whispersystems.libsignal.NoSessionException;
import org.whispersystems.libsignal.SessionCipher;
import org.whispersystems.libsignal.SignalProtocolAddress;
import org.whispersystems.libsignal.UntrustedIdentityException;
import org.whispersystems.libsignal.protocol.CiphertextMessage;
import org.whispersystems.libsignal.protocol.PreKeySignalMessage;
import org.whispersystems.libsignal.protocol.SignalMessage;
import org.whispersystems.libsignal.util.guava.Optional;
import java.util.Iterator;
import java.util.List;
import de.pixart.messenger.Config;
import de.pixart.messenger.entities.Account;
import de.pixart.messenger.utils.CryptoHelper;
public class XmppAxolotlSession implements Comparable<XmppAxolotlSession> {
private final SessionCipher cipher;
private final SQLiteAxolotlStore sqLiteAxolotlStore;
private final SignalProtocolAddress remoteAddress;
private final Account account;
private IdentityKey identityKey;
private Integer preKeyId = null;
private boolean fresh = true;
public XmppAxolotlSession(Account account, SQLiteAxolotlStore store, SignalProtocolAddress remoteAddress, IdentityKey identityKey) {
this(account, store, remoteAddress);
this.identityKey = identityKey;
}
public XmppAxolotlSession(Account account, SQLiteAxolotlStore store, SignalProtocolAddress remoteAddress) {
this.cipher = new SessionCipher(store, remoteAddress);
this.remoteAddress = remoteAddress;
this.sqLiteAxolotlStore = store;
this.account = account;
}
public Integer getPreKeyIdAndReset() {
final Integer preKeyId = this.preKeyId;
this.preKeyId = null;
return preKeyId;
}
public String getFingerprint() {
return identityKey == null ? null : CryptoHelper.bytesToHex(identityKey.getPublicKey().serialize());
}
public IdentityKey getIdentityKey() {
return identityKey;
}
public SignalProtocolAddress getRemoteAddress() {
return remoteAddress;
}
public boolean isFresh() {
return fresh;
}
public void setNotFresh() {
this.fresh = false;
}
protected void setTrust(FingerprintStatus status) {
sqLiteAxolotlStore.setFingerprintStatus(getFingerprint(), status);
}
public FingerprintStatus getTrust() {
FingerprintStatus status = sqLiteAxolotlStore.getFingerprintStatus(getFingerprint());
return (status == null) ? FingerprintStatus.createActiveUndecided() : status;
}
@Nullable
byte[] processReceiving(List<AxolotlKey> possibleKeys) throws CryptoFailedException {
byte[] plaintext = null;
FingerprintStatus status = getTrust();
if (!status.isCompromised()) {
Iterator<AxolotlKey> iterator = possibleKeys.iterator();
while (iterator.hasNext()) {
AxolotlKey encryptedKey = iterator.next();
try {
if (encryptedKey.prekey) {
PreKeySignalMessage preKeySignalMessage = new PreKeySignalMessage(encryptedKey.key);
Optional<Integer> optionalPreKeyId = preKeySignalMessage.getPreKeyId();
IdentityKey identityKey = preKeySignalMessage.getIdentityKey();
if (!optionalPreKeyId.isPresent()) {
if (iterator.hasNext()) {
continue;
}
throw new CryptoFailedException("PreKeyWhisperMessage did not contain a PreKeyId");
}
preKeyId = optionalPreKeyId.get();
if (this.identityKey != null && !this.identityKey.equals(identityKey)) {
if (iterator.hasNext()) {
continue;
}
throw new CryptoFailedException("Received PreKeyWhisperMessage but preexisting identity key changed.");
}
this.identityKey = identityKey;
plaintext = cipher.decrypt(preKeySignalMessage);
} else {
SignalMessage signalMessage = new SignalMessage(encryptedKey.key);
try {
plaintext = cipher.decrypt(signalMessage);
} catch (InvalidMessageException e) {
if (iterator.hasNext()) {
Log.w(Config.LOGTAG, account.getJid().asBareJid() + ": ignoring crypto exception because possible keys left to try", e);
continue;
}
throw new BrokenSessionException(this.remoteAddress, e);
} catch (NoSessionException e) {
if (iterator.hasNext()) {
Log.w(Config.LOGTAG, account.getJid().asBareJid() + ": ignoring crypto exception because possible keys left to try", e);
continue;
}
throw new BrokenSessionException(this.remoteAddress, e);
}
preKeyId = null; //better safe than sorry because we use that to do special after prekey handling
}
} catch (InvalidVersionException | InvalidKeyException | LegacyMessageException | InvalidMessageException | DuplicateMessageException | InvalidKeyIdException | UntrustedIdentityException e) {
if (iterator.hasNext()) {
Log.w(Config.LOGTAG, account.getJid().asBareJid() + ": ignoring crypto exception because possible keys left to try", e);
continue;
}
throw new CryptoFailedException("Error decrypting SignalMessage", e);
}
if (iterator.hasNext()) {
break;
}
}
if (!status.isActive()) {
setTrust(status.toActive());
//TODO: also (re)add to device list?
}
} else {
throw new CryptoFailedException("not encrypting omemo message from fingerprint " + getFingerprint() + " because it was marked as compromised");
}
return plaintext;
}
@Nullable
public AxolotlKey processSending(@NonNull byte[] outgoingMessage, boolean ignoreSessionTrust) {
FingerprintStatus status = getTrust();
if (ignoreSessionTrust || status.isTrustedAndActive()) {
try {
CiphertextMessage ciphertextMessage = cipher.encrypt(outgoingMessage);
return new AxolotlKey(getRemoteAddress().getDeviceId(), ciphertextMessage.serialize(), ciphertextMessage.getType() == CiphertextMessage.PREKEY_TYPE);
} catch (UntrustedIdentityException e) {
return null;
}
} else {
return null;
}
}
public Account getAccount() {
return account;
}
@Override
public int compareTo(XmppAxolotlSession o) {
return getTrust().compareTo(o.getTrust());
}
public static class AxolotlKey {
public final byte[] key;
public final boolean prekey;
public final int deviceId;
public AxolotlKey(int deviceId, byte[] key, boolean prekey) {
this.deviceId = deviceId;
this.key = key;
this.prekey = prekey;
}
}
}
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