1package eu.siacs.conversations.crypto;
  2
  3import java.math.BigInteger;
  4import java.security.KeyFactory;
  5import java.security.KeyPair;
  6import java.security.KeyPairGenerator;
  7import java.security.NoSuchAlgorithmException;
  8import java.security.PrivateKey;
  9import java.security.PublicKey;
 10import java.security.spec.DSAPrivateKeySpec;
 11import java.security.spec.DSAPublicKeySpec;
 12import java.security.spec.InvalidKeySpecException;
 13
 14import org.json.JSONException;
 15import org.json.JSONObject;
 16
 17import android.util.Log;
 18
 19import eu.siacs.conversations.Config;
 20import eu.siacs.conversations.entities.Account;
 21import eu.siacs.conversations.entities.Conversation;
 22import eu.siacs.conversations.services.XmppConnectionService;
 23import eu.siacs.conversations.utils.CryptoHelper;
 24import eu.siacs.conversations.xmpp.jid.InvalidJidException;
 25import eu.siacs.conversations.xmpp.jid.Jid;
 26import eu.siacs.conversations.xmpp.stanzas.MessagePacket;
 27
 28import net.java.otr4j.OtrEngineHost;
 29import net.java.otr4j.OtrException;
 30import net.java.otr4j.OtrPolicy;
 31import net.java.otr4j.OtrPolicyImpl;
 32import net.java.otr4j.crypto.OtrCryptoEngineImpl;
 33import net.java.otr4j.crypto.OtrCryptoException;
 34import net.java.otr4j.session.InstanceTag;
 35import net.java.otr4j.session.SessionID;
 36
 37public class OtrEngine extends OtrCryptoEngineImpl implements OtrEngineHost {
 38
 39	private Account account;
 40	private OtrPolicy otrPolicy;
 41	private KeyPair keyPair;
 42	private XmppConnectionService mXmppConnectionService;
 43
 44	public OtrEngine(XmppConnectionService service, Account account) {
 45		this.account = account;
 46		this.otrPolicy = new OtrPolicyImpl();
 47		this.otrPolicy.setAllowV1(false);
 48		this.otrPolicy.setAllowV2(true);
 49		this.otrPolicy.setAllowV3(true);
 50		this.keyPair = loadKey(account.getKeys());
 51		this.mXmppConnectionService = service;
 52	}
 53
 54	private KeyPair loadKey(JSONObject keys) {
 55		if (keys == null) {
 56			return null;
 57		}
 58		try {
 59			BigInteger x = new BigInteger(keys.getString("otr_x"), 16);
 60			BigInteger y = new BigInteger(keys.getString("otr_y"), 16);
 61			BigInteger p = new BigInteger(keys.getString("otr_p"), 16);
 62			BigInteger q = new BigInteger(keys.getString("otr_q"), 16);
 63			BigInteger g = new BigInteger(keys.getString("otr_g"), 16);
 64			KeyFactory keyFactory = KeyFactory.getInstance("DSA");
 65			DSAPublicKeySpec pubKeySpec = new DSAPublicKeySpec(y, p, q, g);
 66			DSAPrivateKeySpec privateKeySpec = new DSAPrivateKeySpec(x, p, q, g);
 67			PublicKey publicKey = keyFactory.generatePublic(pubKeySpec);
 68			PrivateKey privateKey = keyFactory.generatePrivate(privateKeySpec);
 69			return new KeyPair(publicKey, privateKey);
 70		} catch (JSONException e) {
 71			return null;
 72		} catch (NoSuchAlgorithmException e) {
 73			return null;
 74		} catch (InvalidKeySpecException e) {
 75			return null;
 76		}
 77	}
 78
 79	private void saveKey() {
 80		PublicKey publicKey = keyPair.getPublic();
 81		PrivateKey privateKey = keyPair.getPrivate();
 82		KeyFactory keyFactory;
 83		try {
 84			keyFactory = KeyFactory.getInstance("DSA");
 85			DSAPrivateKeySpec privateKeySpec = keyFactory.getKeySpec(
 86					privateKey, DSAPrivateKeySpec.class);
 87			DSAPublicKeySpec publicKeySpec = keyFactory.getKeySpec(publicKey,
 88					DSAPublicKeySpec.class);
 89			this.account.setKey("otr_x", privateKeySpec.getX().toString(16));
 90			this.account.setKey("otr_g", privateKeySpec.getG().toString(16));
 91			this.account.setKey("otr_p", privateKeySpec.getP().toString(16));
 92			this.account.setKey("otr_q", privateKeySpec.getQ().toString(16));
 93			this.account.setKey("otr_y", publicKeySpec.getY().toString(16));
 94		} catch (final NoSuchAlgorithmException | InvalidKeySpecException e) {
 95			e.printStackTrace();
 96		}
 97
 98    }
 99
100	@Override
101	public void askForSecret(SessionID id, InstanceTag instanceTag, String question) {
102		try {
103			final Jid jid = Jid.fromSessionID(id);
104			Conversation conversation = this.mXmppConnectionService.find(this.account,jid);
105			if (conversation!=null) {
106				conversation.smp().hint = question;
107				conversation.smp().status = Conversation.Smp.STATUS_CONTACT_REQUESTED;
108				mXmppConnectionService.updateConversationUi();
109			}
110		} catch (InvalidJidException e) {
111			Log.d(Config.LOGTAG,account.getJid().toBareJid()+": smp in invalid session "+id.toString());
112		}
113	}
114
115	@Override
116	public void finishedSessionMessage(SessionID arg0, String arg1)
117			throws OtrException {
118
119	}
120
121	@Override
122	public String getFallbackMessage(SessionID arg0) {
123		return "I would like to start a private (OTR encrypted) conversation but your client doesn’t seem to support that";
124	}
125
126	@Override
127	public byte[] getLocalFingerprintRaw(SessionID arg0) {
128		try {
129			return getFingerprintRaw(getPublicKey());
130		} catch (OtrCryptoException e) {
131			return null;
132		}
133	}
134
135	public PublicKey getPublicKey() {
136		if (this.keyPair == null) {
137			return null;
138		}
139		return this.keyPair.getPublic();
140	}
141
142	@Override
143	public KeyPair getLocalKeyPair(SessionID arg0) throws OtrException {
144		if (this.keyPair == null) {
145			KeyPairGenerator kg;
146			try {
147				kg = KeyPairGenerator.getInstance("DSA");
148				this.keyPair = kg.genKeyPair();
149				this.saveKey();
150				mXmppConnectionService.databaseBackend.updateAccount(account);
151			} catch (NoSuchAlgorithmException e) {
152				Log.d(Config.LOGTAG,
153						"error generating key pair " + e.getMessage());
154			}
155		}
156		return this.keyPair;
157	}
158
159	@Override
160	public String getReplyForUnreadableMessage(SessionID arg0) {
161		// TODO Auto-generated method stub
162		return null;
163	}
164
165	@Override
166	public OtrPolicy getSessionPolicy(SessionID arg0) {
167		return otrPolicy;
168	}
169
170	@Override
171	public void injectMessage(SessionID session, String body)
172			throws OtrException {
173		MessagePacket packet = new MessagePacket();
174		packet.setFrom(account.getJid());
175		if (session.getUserID().isEmpty()) {
176			packet.setAttribute("to", session.getAccountID());
177		} else {
178			packet.setAttribute("to", session.getAccountID() + "/" + session.getUserID());
179		}
180		packet.setBody(body);
181		packet.addChild("private", "urn:xmpp:carbons:2");
182		packet.addChild("no-copy", "urn:xmpp:hints");
183		packet.addChild("no-store", "urn:xmpp:hints");
184		packet.setType(MessagePacket.TYPE_CHAT);
185		account.getXmppConnection().sendMessagePacket(packet);
186	}
187
188	@Override
189	public void messageFromAnotherInstanceReceived(SessionID id) {
190		Log.d(Config.LOGTAG,
191				"unreadable message received from " + id.getAccountID());
192	}
193
194	@Override
195	public void multipleInstancesDetected(SessionID arg0) {
196		// TODO Auto-generated method stub
197
198	}
199
200	@Override
201	public void requireEncryptedMessage(SessionID arg0, String arg1)
202			throws OtrException {
203		// TODO Auto-generated method stub
204
205	}
206
207	@Override
208	public void showError(SessionID arg0, String arg1) throws OtrException {
209		Log.d(Config.LOGTAG,"show error");
210	}
211
212	@Override
213	public void smpAborted(SessionID id) throws OtrException {
214		setSmpStatus(id, Conversation.Smp.STATUS_NONE);
215	}
216
217	private void setSmpStatus(SessionID id, int status) {
218		try {
219			final Jid jid = Jid.fromSessionID(id);
220			Conversation conversation = this.mXmppConnectionService.find(this.account,jid);
221			if (conversation!=null) {
222				conversation.smp().status = status;
223				mXmppConnectionService.updateConversationUi();
224			}
225		} catch (final InvalidJidException ignored) {
226
227		}
228	}
229
230	@Override
231	public void smpError(SessionID id, int arg1, boolean arg2)
232			throws OtrException {
233		setSmpStatus(id, Conversation.Smp.STATUS_NONE);
234	}
235
236	@Override
237	public void unencryptedMessageReceived(SessionID arg0, String arg1)
238			throws OtrException {
239		throw new OtrException(new Exception("unencrypted message received"));
240	}
241
242	@Override
243	public void unreadableMessageReceived(SessionID arg0) throws OtrException {
244		Log.d(Config.LOGTAG,"unreadable message received");
245		throw new OtrException(new Exception("unreadable message received"));
246	}
247
248	@Override
249	public void unverify(SessionID id, String arg1) {
250		setSmpStatus(id, Conversation.Smp.STATUS_FAILED);
251	}
252
253	@Override
254	public void verify(SessionID id, String fingerprint, boolean approved) {
255		Log.d(Config.LOGTAG,"OtrEngine.verify("+id.toString()+","+fingerprint+","+String.valueOf(approved)+")");
256		try {
257			final Jid jid = Jid.fromSessionID(id);
258			Conversation conversation = this.mXmppConnectionService.find(this.account,jid);
259			if (conversation!=null) {
260				if (approved) {
261					conversation.getContact().addOtrFingerprint(fingerprint);
262				}
263				conversation.smp().hint = null;
264				conversation.smp().status = Conversation.Smp.STATUS_VERIFIED;
265				mXmppConnectionService.updateConversationUi();
266				mXmppConnectionService.syncRosterToDisk(conversation.getAccount());
267			}
268		} catch (final InvalidJidException ignored) {
269		}
270	}
271
272}