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