AxolotlService.java

  1package eu.siacs.conversations.crypto.axolotl;
  2
  3import android.support.annotation.NonNull;
  4import android.support.annotation.Nullable;
  5import android.util.Log;
  6
  7import org.bouncycastle.jce.provider.BouncyCastleProvider;
  8import org.whispersystems.libaxolotl.AxolotlAddress;
  9import org.whispersystems.libaxolotl.IdentityKey;
 10import org.whispersystems.libaxolotl.IdentityKeyPair;
 11import org.whispersystems.libaxolotl.InvalidKeyException;
 12import org.whispersystems.libaxolotl.InvalidKeyIdException;
 13import org.whispersystems.libaxolotl.SessionBuilder;
 14import org.whispersystems.libaxolotl.UntrustedIdentityException;
 15import org.whispersystems.libaxolotl.ecc.ECPublicKey;
 16import org.whispersystems.libaxolotl.state.PreKeyBundle;
 17import org.whispersystems.libaxolotl.state.PreKeyRecord;
 18import org.whispersystems.libaxolotl.state.SignedPreKeyRecord;
 19import org.whispersystems.libaxolotl.util.KeyHelper;
 20
 21import java.security.Security;
 22import java.util.Arrays;
 23import java.util.HashMap;
 24import java.util.HashSet;
 25import java.util.List;
 26import java.util.Map;
 27import java.util.Random;
 28import java.util.Set;
 29
 30import eu.siacs.conversations.Config;
 31import eu.siacs.conversations.entities.Account;
 32import eu.siacs.conversations.entities.Contact;
 33import eu.siacs.conversations.entities.Conversation;
 34import eu.siacs.conversations.entities.Message;
 35import eu.siacs.conversations.parser.IqParser;
 36import eu.siacs.conversations.services.XmppConnectionService;
 37import eu.siacs.conversations.utils.SerialSingleThreadExecutor;
 38import eu.siacs.conversations.xml.Element;
 39import eu.siacs.conversations.xmpp.OnIqPacketReceived;
 40import eu.siacs.conversations.xmpp.jid.InvalidJidException;
 41import eu.siacs.conversations.xmpp.jid.Jid;
 42import eu.siacs.conversations.xmpp.stanzas.IqPacket;
 43
 44public class AxolotlService {
 45
 46	public static final String PEP_PREFIX = "eu.siacs.conversations.axolotl";
 47	public static final String PEP_DEVICE_LIST = PEP_PREFIX + ".devicelist";
 48	public static final String PEP_BUNDLES = PEP_PREFIX + ".bundles";
 49
 50	public static final String LOGPREFIX = "AxolotlService";
 51
 52	public static final int NUM_KEYS_TO_PUBLISH = 100;
 53	public static final int publishTriesThreshold = 3;
 54
 55	private final Account account;
 56	private final XmppConnectionService mXmppConnectionService;
 57	private final SQLiteAxolotlStore axolotlStore;
 58	private final SessionMap sessions;
 59	private final Map<Jid, Set<Integer>> deviceIds;
 60	private final Map<String, XmppAxolotlMessage> messageCache;
 61	private final FetchStatusMap fetchStatusMap;
 62	private final SerialSingleThreadExecutor executor;
 63	private int numPublishTriesOnEmptyPep = 0;
 64	private boolean pepBroken = false;
 65
 66	private static class AxolotlAddressMap<T> {
 67		protected Map<String, Map<Integer, T>> map;
 68		protected final Object MAP_LOCK = new Object();
 69
 70		public AxolotlAddressMap() {
 71			this.map = new HashMap<>();
 72		}
 73
 74		public void put(AxolotlAddress address, T value) {
 75			synchronized (MAP_LOCK) {
 76				Map<Integer, T> devices = map.get(address.getName());
 77				if (devices == null) {
 78					devices = new HashMap<>();
 79					map.put(address.getName(), devices);
 80				}
 81				devices.put(address.getDeviceId(), value);
 82			}
 83		}
 84
 85		public T get(AxolotlAddress address) {
 86			synchronized (MAP_LOCK) {
 87				Map<Integer, T> devices = map.get(address.getName());
 88				if (devices == null) {
 89					return null;
 90				}
 91				return devices.get(address.getDeviceId());
 92			}
 93		}
 94
 95		public Map<Integer, T> getAll(AxolotlAddress address) {
 96			synchronized (MAP_LOCK) {
 97				Map<Integer, T> devices = map.get(address.getName());
 98				if (devices == null) {
 99					return new HashMap<>();
100				}
101				return devices;
102			}
103		}
104
105		public boolean hasAny(AxolotlAddress address) {
106			synchronized (MAP_LOCK) {
107				Map<Integer, T> devices = map.get(address.getName());
108				return devices != null && !devices.isEmpty();
109			}
110		}
111
112		public void clear() {
113			map.clear();
114		}
115
116	}
117
118	private static class SessionMap extends AxolotlAddressMap<XmppAxolotlSession> {
119		private final XmppConnectionService xmppConnectionService;
120		private final Account account;
121
122		public SessionMap(XmppConnectionService service, SQLiteAxolotlStore store, Account account) {
123			super();
124			this.xmppConnectionService = service;
125			this.account = account;
126			this.fillMap(store);
127		}
128
129		private void putDevicesForJid(String bareJid, List<Integer> deviceIds, SQLiteAxolotlStore store) {
130			for (Integer deviceId : deviceIds) {
131				AxolotlAddress axolotlAddress = new AxolotlAddress(bareJid, deviceId);
132				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building session for remote address: " + axolotlAddress.toString());
133				String fingerprint = store.loadSession(axolotlAddress).getSessionState().getRemoteIdentityKey().getFingerprint().replaceAll("\\s", "");
134				this.put(axolotlAddress, new XmppAxolotlSession(account, store, axolotlAddress, fingerprint));
135			}
136		}
137
138		private void fillMap(SQLiteAxolotlStore store) {
139			List<Integer> deviceIds = store.getSubDeviceSessions(account.getJid().toBareJid().toString());
140			putDevicesForJid(account.getJid().toBareJid().toString(), deviceIds, store);
141			for (Contact contact : account.getRoster().getContacts()) {
142				Jid bareJid = contact.getJid().toBareJid();
143				if (bareJid == null) {
144					continue; // FIXME: handle this?
145				}
146				String address = bareJid.toString();
147				deviceIds = store.getSubDeviceSessions(address);
148				putDevicesForJid(address, deviceIds, store);
149			}
150
151		}
152
153		@Override
154		public void put(AxolotlAddress address, XmppAxolotlSession value) {
155			super.put(address, value);
156			value.setNotFresh();
157			xmppConnectionService.syncRosterToDisk(account);
158		}
159
160		public void put(XmppAxolotlSession session) {
161			this.put(session.getRemoteAddress(), session);
162		}
163	}
164
165	private static enum FetchStatus {
166		PENDING,
167		SUCCESS,
168		ERROR
169	}
170
171	private static class FetchStatusMap extends AxolotlAddressMap<FetchStatus> {
172
173	}
174
175	public static String getLogprefix(Account account) {
176		return LOGPREFIX + " (" + account.getJid().toBareJid().toString() + "): ";
177	}
178
179	public AxolotlService(Account account, XmppConnectionService connectionService) {
180		if (Security.getProvider("BC") == null) {
181			Security.addProvider(new BouncyCastleProvider());
182		}
183		this.mXmppConnectionService = connectionService;
184		this.account = account;
185		this.axolotlStore = new SQLiteAxolotlStore(this.account, this.mXmppConnectionService);
186		this.deviceIds = new HashMap<>();
187		this.messageCache = new HashMap<>();
188		this.sessions = new SessionMap(mXmppConnectionService, axolotlStore, account);
189		this.fetchStatusMap = new FetchStatusMap();
190		this.executor = new SerialSingleThreadExecutor();
191	}
192
193	public IdentityKey getOwnPublicKey() {
194		return axolotlStore.getIdentityKeyPair().getPublicKey();
195	}
196
197	public Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust) {
198		return axolotlStore.getContactKeysWithTrust(account.getJid().toBareJid().toString(), trust);
199	}
200
201	public Set<IdentityKey> getKeysWithTrust(XmppAxolotlSession.Trust trust, Contact contact) {
202		return axolotlStore.getContactKeysWithTrust(contact.getJid().toBareJid().toString(), trust);
203	}
204
205	public long getNumTrustedKeys(Contact contact) {
206		return axolotlStore.getContactNumTrustedKeys(contact.getJid().toBareJid().toString());
207	}
208
209	private AxolotlAddress getAddressForJid(Jid jid) {
210		return new AxolotlAddress(jid.toString(), 0);
211	}
212
213	private Set<XmppAxolotlSession> findOwnSessions() {
214		AxolotlAddress ownAddress = getAddressForJid(account.getJid().toBareJid());
215		Set<XmppAxolotlSession> ownDeviceSessions = new HashSet<>(this.sessions.getAll(ownAddress).values());
216		return ownDeviceSessions;
217	}
218
219	private Set<XmppAxolotlSession> findSessionsforContact(Contact contact) {
220		AxolotlAddress contactAddress = getAddressForJid(contact.getJid());
221		Set<XmppAxolotlSession> sessions = new HashSet<>(this.sessions.getAll(contactAddress).values());
222		return sessions;
223	}
224
225	private boolean hasAny(Contact contact) {
226		AxolotlAddress contactAddress = getAddressForJid(contact.getJid());
227		return sessions.hasAny(contactAddress);
228	}
229
230	public void regenerateKeys() {
231		axolotlStore.regenerate();
232		sessions.clear();
233		fetchStatusMap.clear();
234		publishBundlesIfNeeded();
235		publishOwnDeviceIdIfNeeded();
236	}
237
238	public int getOwnDeviceId() {
239		return axolotlStore.getLocalRegistrationId();
240	}
241
242	public Set<Integer> getOwnDeviceIds() {
243		return this.deviceIds.get(account.getJid().toBareJid());
244	}
245
246	private void setTrustOnSessions(final Jid jid, @NonNull final Set<Integer> deviceIds,
247	                                final XmppAxolotlSession.Trust from,
248	                                final XmppAxolotlSession.Trust to) {
249		for (Integer deviceId : deviceIds) {
250			AxolotlAddress address = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
251			XmppAxolotlSession session = sessions.get(address);
252			if (session != null && session.getFingerprint() != null
253					&& session.getTrust() == from) {
254				session.setTrust(to);
255			}
256		}
257	}
258
259	public void registerDevices(final Jid jid, @NonNull final Set<Integer> deviceIds) {
260		if (jid.toBareJid().equals(account.getJid().toBareJid())) {
261			if (!deviceIds.isEmpty()) {
262				Log.d(Config.LOGTAG, getLogprefix(account) + "Received non-empty own device list. Resetting publish attemps and pepBroken status.");
263				pepBroken = false;
264				numPublishTriesOnEmptyPep = 0;
265			}
266			if (deviceIds.contains(getOwnDeviceId())) {
267				deviceIds.remove(getOwnDeviceId());
268			} else {
269				publishOwnDeviceId(deviceIds);
270			}
271			for (Integer deviceId : deviceIds) {
272				AxolotlAddress ownDeviceAddress = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
273				if (sessions.get(ownDeviceAddress) == null) {
274					buildSessionFromPEP(ownDeviceAddress);
275				}
276			}
277		}
278		Set<Integer> expiredDevices = new HashSet<>(axolotlStore.getSubDeviceSessions(jid.toBareJid().toString()));
279		expiredDevices.removeAll(deviceIds);
280		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.TRUSTED,
281				XmppAxolotlSession.Trust.INACTIVE_TRUSTED);
282		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.UNDECIDED,
283				XmppAxolotlSession.Trust.INACTIVE_UNDECIDED);
284		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.UNTRUSTED,
285				XmppAxolotlSession.Trust.INACTIVE_UNTRUSTED);
286		Set<Integer> newDevices = new HashSet<>(deviceIds);
287		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_TRUSTED,
288				XmppAxolotlSession.Trust.TRUSTED);
289		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_UNDECIDED,
290				XmppAxolotlSession.Trust.UNDECIDED);
291		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_UNTRUSTED,
292				XmppAxolotlSession.Trust.UNTRUSTED);
293		this.deviceIds.put(jid, deviceIds);
294		mXmppConnectionService.keyStatusUpdated();
295	}
296
297	public void wipeOtherPepDevices() {
298		if (pepBroken) {
299			Log.d(Config.LOGTAG, getLogprefix(account) + "wipeOtherPepDevices called, but PEP is broken. Ignoring... ");
300			return;
301		}
302		Set<Integer> deviceIds = new HashSet<>();
303		deviceIds.add(getOwnDeviceId());
304		IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIds);
305		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Wiping all other devices from Pep:" + publish);
306		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
307			@Override
308			public void onIqPacketReceived(Account account, IqPacket packet) {
309				// TODO: implement this!
310			}
311		});
312	}
313
314	public void purgeKey(IdentityKey identityKey) {
315		axolotlStore.setFingerprintTrust(identityKey.getFingerprint().replaceAll("\\s", ""), XmppAxolotlSession.Trust.COMPROMISED);
316	}
317
318	public void publishOwnDeviceIdIfNeeded() {
319		if (pepBroken) {
320			Log.d(Config.LOGTAG, getLogprefix(account) + "publishOwnDeviceIdIfNeeded called, but PEP is broken. Ignoring... ");
321			return;
322		}
323		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveDeviceIds(account.getJid().toBareJid());
324		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
325			@Override
326			public void onIqPacketReceived(Account account, IqPacket packet) {
327				if (packet.getType() == IqPacket.TYPE.RESULT) {
328					Element item = mXmppConnectionService.getIqParser().getItem(packet);
329					Set<Integer> deviceIds = mXmppConnectionService.getIqParser().deviceIds(item);
330					if (!deviceIds.contains(getOwnDeviceId())) {
331						publishOwnDeviceId(deviceIds);
332					}
333				} else {
334					Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while retrieving Device Ids" + packet.findChild("error"));
335				}
336			}
337		});
338	}
339
340	public void publishOwnDeviceId(Set<Integer> deviceIds) {
341		if (!deviceIds.contains(getOwnDeviceId())) {
342			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Own device " + getOwnDeviceId() + " not in PEP devicelist.");
343			if (deviceIds.isEmpty()) {
344				if (numPublishTriesOnEmptyPep >= publishTriesThreshold) {
345					Log.w(Config.LOGTAG, getLogprefix(account) + "Own device publish attempt threshold exceeded, aborting...");
346					pepBroken = true;
347					return;
348				} else {
349					numPublishTriesOnEmptyPep++;
350					Log.w(Config.LOGTAG, getLogprefix(account) + "Own device list empty, attempting to publish (try " + numPublishTriesOnEmptyPep + ")");
351				}
352			} else {
353				numPublishTriesOnEmptyPep = 0;
354			}
355			deviceIds.add(getOwnDeviceId());
356			IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIds);
357			mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
358				@Override
359				public void onIqPacketReceived(Account account, IqPacket packet) {
360					if (packet.getType() != IqPacket.TYPE.RESULT) {
361						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing own device id" + packet.findChild("error"));
362					}
363				}
364			});
365		}
366	}
367
368	public void publishBundlesIfNeeded() {
369		if (!pepBroken) {
370			Log.d(Config.LOGTAG, getLogprefix(account) + "publishBundlesIfNeeded called, but PEP is broken. Ignoring... ");
371			return;
372		}
373		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(account.getJid().toBareJid(), getOwnDeviceId());
374		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
375			@Override
376			public void onIqPacketReceived(Account account, IqPacket packet) {
377				if (packet.getType() == IqPacket.TYPE.RESULT) {
378					PreKeyBundle bundle = mXmppConnectionService.getIqParser().bundle(packet);
379					Map<Integer, ECPublicKey> keys = mXmppConnectionService.getIqParser().preKeyPublics(packet);
380					boolean flush = false;
381					if (bundle == null) {
382						Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid bundle:" + packet);
383						bundle = new PreKeyBundle(-1, -1, -1, null, -1, null, null, null);
384						flush = true;
385					}
386					if (keys == null) {
387						Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid prekeys:" + packet);
388					}
389					try {
390						boolean changed = false;
391						// Validate IdentityKey
392						IdentityKeyPair identityKeyPair = axolotlStore.getIdentityKeyPair();
393						if (flush || !identityKeyPair.getPublicKey().equals(bundle.getIdentityKey())) {
394							Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding own IdentityKey " + identityKeyPair.getPublicKey() + " to PEP.");
395							changed = true;
396						}
397
398						// Validate signedPreKeyRecord + ID
399						SignedPreKeyRecord signedPreKeyRecord;
400						int numSignedPreKeys = axolotlStore.loadSignedPreKeys().size();
401						try {
402							signedPreKeyRecord = axolotlStore.loadSignedPreKey(bundle.getSignedPreKeyId());
403							if (flush
404									|| !bundle.getSignedPreKey().equals(signedPreKeyRecord.getKeyPair().getPublicKey())
405									|| !Arrays.equals(bundle.getSignedPreKeySignature(), signedPreKeyRecord.getSignature())) {
406								Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
407								signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
408								axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
409								changed = true;
410							}
411						} catch (InvalidKeyIdException e) {
412							Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
413							signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
414							axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
415							changed = true;
416						}
417
418						// Validate PreKeys
419						Set<PreKeyRecord> preKeyRecords = new HashSet<>();
420						if (keys != null) {
421							for (Integer id : keys.keySet()) {
422								try {
423									PreKeyRecord preKeyRecord = axolotlStore.loadPreKey(id);
424									if (preKeyRecord.getKeyPair().getPublicKey().equals(keys.get(id))) {
425										preKeyRecords.add(preKeyRecord);
426									}
427								} catch (InvalidKeyIdException ignored) {
428								}
429							}
430						}
431						int newKeys = NUM_KEYS_TO_PUBLISH - preKeyRecords.size();
432						if (newKeys > 0) {
433							List<PreKeyRecord> newRecords = KeyHelper.generatePreKeys(
434									axolotlStore.getCurrentPreKeyId() + 1, newKeys);
435							preKeyRecords.addAll(newRecords);
436							for (PreKeyRecord record : newRecords) {
437								axolotlStore.storePreKey(record.getId(), record);
438							}
439							changed = true;
440							Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding " + newKeys + " new preKeys to PEP.");
441						}
442
443
444						if (changed) {
445							IqPacket publish = mXmppConnectionService.getIqGenerator().publishBundles(
446									signedPreKeyRecord, axolotlStore.getIdentityKeyPair().getPublicKey(),
447									preKeyRecords, getOwnDeviceId());
448							Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ": Bundle " + getOwnDeviceId() + " in PEP not current. Publishing: " + publish);
449							mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
450								@Override
451								public void onIqPacketReceived(Account account, IqPacket packet) {
452									// TODO: implement this!
453									Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Published bundle, got: " + packet);
454								}
455							});
456						}
457					} catch (InvalidKeyException e) {
458						Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Failed to publish bundle " + getOwnDeviceId() + ", reason: " + e.getMessage());
459						return;
460					}
461				} else {
462					Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing Bundle:" + packet.findChild("error"));
463				}
464			}
465		});
466	}
467
468	public boolean isContactAxolotlCapable(Contact contact) {
469
470		Jid jid = contact.getJid().toBareJid();
471		AxolotlAddress address = new AxolotlAddress(jid.toString(), 0);
472		return sessions.hasAny(address) ||
473				(deviceIds.containsKey(jid) && !deviceIds.get(jid).isEmpty());
474	}
475
476	public XmppAxolotlSession.Trust getFingerprintTrust(String fingerprint) {
477		return axolotlStore.getFingerprintTrust(fingerprint);
478	}
479
480	public void setFingerprintTrust(String fingerprint, XmppAxolotlSession.Trust trust) {
481		axolotlStore.setFingerprintTrust(fingerprint, trust);
482	}
483
484	private void buildSessionFromPEP(final AxolotlAddress address) {
485		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building new sesstion for " + address.getDeviceId());
486
487		try {
488			IqPacket bundlesPacket = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(
489					Jid.fromString(address.getName()), address.getDeviceId());
490			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Retrieving bundle: " + bundlesPacket);
491			mXmppConnectionService.sendIqPacket(account, bundlesPacket, new OnIqPacketReceived() {
492				private void finish() {
493					AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
494					if (!fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
495							&& !fetchStatusMap.getAll(address).containsValue(FetchStatus.PENDING)) {
496						mXmppConnectionService.keyStatusUpdated();
497					}
498				}
499
500				@Override
501				public void onIqPacketReceived(Account account, IqPacket packet) {
502					if (packet.getType() == IqPacket.TYPE.RESULT) {
503						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received preKey IQ packet, processing...");
504						final IqParser parser = mXmppConnectionService.getIqParser();
505						final List<PreKeyBundle> preKeyBundleList = parser.preKeys(packet);
506						final PreKeyBundle bundle = parser.bundle(packet);
507						if (preKeyBundleList.isEmpty() || bundle == null) {
508							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "preKey IQ packet invalid: " + packet);
509							fetchStatusMap.put(address, FetchStatus.ERROR);
510							finish();
511							return;
512						}
513						Random random = new Random();
514						final PreKeyBundle preKey = preKeyBundleList.get(random.nextInt(preKeyBundleList.size()));
515						if (preKey == null) {
516							//should never happen
517							fetchStatusMap.put(address, FetchStatus.ERROR);
518							finish();
519							return;
520						}
521
522						final PreKeyBundle preKeyBundle = new PreKeyBundle(0, address.getDeviceId(),
523								preKey.getPreKeyId(), preKey.getPreKey(),
524								bundle.getSignedPreKeyId(), bundle.getSignedPreKey(),
525								bundle.getSignedPreKeySignature(), bundle.getIdentityKey());
526
527						axolotlStore.saveIdentity(address.getName(), bundle.getIdentityKey());
528
529						try {
530							SessionBuilder builder = new SessionBuilder(axolotlStore, address);
531							builder.process(preKeyBundle);
532							XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, bundle.getIdentityKey().getFingerprint().replaceAll("\\s", ""));
533							sessions.put(address, session);
534							fetchStatusMap.put(address, FetchStatus.SUCCESS);
535						} catch (UntrustedIdentityException | InvalidKeyException e) {
536							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error building session for " + address + ": "
537									+ e.getClass().getName() + ", " + e.getMessage());
538							fetchStatusMap.put(address, FetchStatus.ERROR);
539						}
540
541						finish();
542					} else {
543						fetchStatusMap.put(address, FetchStatus.ERROR);
544						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while building session:" + packet.findChild("error"));
545						finish();
546						return;
547					}
548				}
549			});
550		} catch (InvalidJidException e) {
551			Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Got address with invalid jid: " + address.getName());
552		}
553	}
554
555	public Set<AxolotlAddress> findDevicesWithoutSession(final Conversation conversation) {
556		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Finding devices without session for " + conversation.getContact().getJid().toBareJid());
557		Jid contactJid = conversation.getContact().getJid().toBareJid();
558		Set<AxolotlAddress> addresses = new HashSet<>();
559		if (deviceIds.get(contactJid) != null) {
560			for (Integer foreignId : this.deviceIds.get(contactJid)) {
561				AxolotlAddress address = new AxolotlAddress(contactJid.toString(), foreignId);
562				if (sessions.get(address) == null) {
563					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
564					if (identityKey != null) {
565						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
566						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey.getFingerprint().replaceAll("\\s", ""));
567						sessions.put(address, session);
568					} else {
569						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + account.getJid().toBareJid() + ":" + foreignId);
570						addresses.add(new AxolotlAddress(contactJid.toString(), foreignId));
571					}
572				}
573			}
574		} else {
575			Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Have no target devices in PEP!");
576		}
577		if (deviceIds.get(account.getJid().toBareJid()) != null) {
578			for (Integer ownId : this.deviceIds.get(account.getJid().toBareJid())) {
579				AxolotlAddress address = new AxolotlAddress(account.getJid().toBareJid().toString(), ownId);
580				if (sessions.get(address) == null) {
581					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
582					if (identityKey != null) {
583						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
584						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey.getFingerprint().replaceAll("\\s", ""));
585						sessions.put(address, session);
586					} else {
587						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + account.getJid().toBareJid() + ":" + ownId);
588						addresses.add(new AxolotlAddress(account.getJid().toBareJid().toString(), ownId));
589					}
590				}
591			}
592		}
593
594		return addresses;
595	}
596
597	public boolean createSessionsIfNeeded(final Conversation conversation) {
598		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Creating axolotl sessions if needed...");
599		boolean newSessions = false;
600		Set<AxolotlAddress> addresses = findDevicesWithoutSession(conversation);
601		for (AxolotlAddress address : addresses) {
602			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Processing device: " + address.toString());
603			FetchStatus status = fetchStatusMap.get(address);
604			if (status == null || status == FetchStatus.ERROR) {
605				fetchStatusMap.put(address, FetchStatus.PENDING);
606				this.buildSessionFromPEP(address);
607				newSessions = true;
608			} else if (status == FetchStatus.PENDING) {
609				newSessions = true;
610			} else {
611				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already fetching bundle for " + address.toString());
612			}
613		}
614
615		return newSessions;
616	}
617
618	public boolean hasPendingKeyFetches(Conversation conversation) {
619		AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
620		AxolotlAddress foreignAddress = new AxolotlAddress(conversation.getJid().toBareJid().toString(), 0);
621		return fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
622				|| fetchStatusMap.getAll(foreignAddress).containsValue(FetchStatus.PENDING);
623
624	}
625
626	@Nullable
627	private XmppAxolotlMessage buildHeader(Contact contact) {
628		final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(
629				contact.getJid().toBareJid(), getOwnDeviceId());
630
631		Set<XmppAxolotlSession> contactSessions = findSessionsforContact(contact);
632		Set<XmppAxolotlSession> ownSessions = findOwnSessions();
633		if (contactSessions.isEmpty()) {
634			return null;
635		}
636		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building axolotl foreign keyElements...");
637		for (XmppAxolotlSession session : contactSessions) {
638			Log.v(Config.LOGTAG, AxolotlService.getLogprefix(account) + session.getRemoteAddress().toString());
639			axolotlMessage.addDevice(session);
640		}
641		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building axolotl own keyElements...");
642		for (XmppAxolotlSession session : ownSessions) {
643			Log.v(Config.LOGTAG, AxolotlService.getLogprefix(account) + session.getRemoteAddress().toString());
644			axolotlMessage.addDevice(session);
645		}
646
647		return axolotlMessage;
648	}
649
650	@Nullable
651	public XmppAxolotlMessage encrypt(Message message) {
652		XmppAxolotlMessage axolotlMessage = buildHeader(message.getContact());
653
654		if (axolotlMessage != null) {
655			final String content;
656			if (message.hasFileOnRemoteHost()) {
657				content = message.getFileParams().url.toString();
658			} else {
659				content = message.getBody();
660			}
661			try {
662				axolotlMessage.encrypt(content);
663			} catch (CryptoFailedException e) {
664				Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
665				return null;
666			}
667		}
668
669		return axolotlMessage;
670	}
671
672	public void preparePayloadMessage(final Message message, final boolean delay) {
673		executor.execute(new Runnable() {
674			@Override
675			public void run() {
676				XmppAxolotlMessage axolotlMessage = encrypt(message);
677				if (axolotlMessage == null) {
678					mXmppConnectionService.markMessage(message, Message.STATUS_SEND_FAILED);
679					//mXmppConnectionService.updateConversationUi();
680				} else {
681					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Generated message, caching: " + message.getUuid());
682					messageCache.put(message.getUuid(), axolotlMessage);
683					mXmppConnectionService.resendMessage(message, delay);
684				}
685			}
686		});
687	}
688
689	public void prepareKeyTransportMessage(final Contact contact, final OnMessageCreatedCallback onMessageCreatedCallback) {
690		executor.execute(new Runnable() {
691			@Override
692			public void run() {
693				XmppAxolotlMessage axolotlMessage = buildHeader(contact);
694				onMessageCreatedCallback.run(axolotlMessage);
695			}
696		});
697	}
698
699	public XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message) {
700		XmppAxolotlMessage axolotlMessage = messageCache.get(message.getUuid());
701		if (axolotlMessage != null) {
702			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache hit: " + message.getUuid());
703			messageCache.remove(message.getUuid());
704		} else {
705			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache miss: " + message.getUuid());
706		}
707		return axolotlMessage;
708	}
709
710	private XmppAxolotlSession recreateUncachedSession(AxolotlAddress address) {
711		IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
712		return (identityKey != null)
713				? new XmppAxolotlSession(account, axolotlStore, address,
714						identityKey.getFingerprint().replaceAll("\\s", ""))
715				: null;
716	}
717
718	private XmppAxolotlSession getReceivingSession(XmppAxolotlMessage message) {
719		AxolotlAddress senderAddress = new AxolotlAddress(message.getFrom().toString(),
720				message.getSenderDeviceId());
721		XmppAxolotlSession session = sessions.get(senderAddress);
722		if (session == null) {
723			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Account: " + account.getJid() + " No axolotl session found while parsing received message " + message);
724			session = recreateUncachedSession(senderAddress);
725			if (session == null) {
726				session = new XmppAxolotlSession(account, axolotlStore, senderAddress);
727			}
728		}
729		return session;
730	}
731
732	public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message) {
733		XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = null;
734
735		XmppAxolotlSession session = getReceivingSession(message);
736		try {
737			plaintextMessage = message.decrypt(session, getOwnDeviceId());
738			Integer preKeyId = session.getPreKeyId();
739			if (preKeyId != null) {
740				publishBundlesIfNeeded();
741				session.resetPreKeyId();
742			}
743		} catch (CryptoFailedException e) {
744			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message: " + e.getMessage());
745		}
746
747		if (session.isFresh() && plaintextMessage != null) {
748			sessions.put(session);
749		}
750
751		return plaintextMessage;
752	}
753
754	public XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message) {
755		XmppAxolotlMessage.XmppAxolotlKeyTransportMessage keyTransportMessage = null;
756
757		XmppAxolotlSession session = getReceivingSession(message);
758		keyTransportMessage = message.getParameters(session, getOwnDeviceId());
759
760		if (session.isFresh() && keyTransportMessage != null) {
761			sessions.put(session);
762		}
763
764		return keyTransportMessage;
765	}
766}