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(true);
235	}
236
237	public int getOwnDeviceId() {
238		return axolotlStore.getLocalRegistrationId();
239	}
240
241	public Set<Integer> getOwnDeviceIds() {
242		return this.deviceIds.get(account.getJid().toBareJid());
243	}
244
245	private void setTrustOnSessions(final Jid jid, @NonNull final Set<Integer> deviceIds,
246	                                final XmppAxolotlSession.Trust from,
247	                                final XmppAxolotlSession.Trust to) {
248		for (Integer deviceId : deviceIds) {
249			AxolotlAddress address = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
250			XmppAxolotlSession session = sessions.get(address);
251			if (session != null && session.getFingerprint() != null
252					&& session.getTrust() == from) {
253				session.setTrust(to);
254			}
255		}
256	}
257
258	public void registerDevices(final Jid jid, @NonNull final Set<Integer> deviceIds) {
259		if (jid.toBareJid().equals(account.getJid().toBareJid())) {
260			if (!deviceIds.isEmpty()) {
261				Log.d(Config.LOGTAG, getLogprefix(account) + "Received non-empty own device list. Resetting publish attemps and pepBroken status.");
262				pepBroken = false;
263				numPublishTriesOnEmptyPep = 0;
264			}
265			if (deviceIds.contains(getOwnDeviceId())) {
266				deviceIds.remove(getOwnDeviceId());
267			} else {
268				publishOwnDeviceId(deviceIds);
269			}
270			for (Integer deviceId : deviceIds) {
271				AxolotlAddress ownDeviceAddress = new AxolotlAddress(jid.toBareJid().toString(), deviceId);
272				if (sessions.get(ownDeviceAddress) == null) {
273					buildSessionFromPEP(ownDeviceAddress);
274				}
275			}
276		}
277		Set<Integer> expiredDevices = new HashSet<>(axolotlStore.getSubDeviceSessions(jid.toBareJid().toString()));
278		expiredDevices.removeAll(deviceIds);
279		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.TRUSTED,
280				XmppAxolotlSession.Trust.INACTIVE_TRUSTED);
281		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.UNDECIDED,
282				XmppAxolotlSession.Trust.INACTIVE_UNDECIDED);
283		setTrustOnSessions(jid, expiredDevices, XmppAxolotlSession.Trust.UNTRUSTED,
284				XmppAxolotlSession.Trust.INACTIVE_UNTRUSTED);
285		Set<Integer> newDevices = new HashSet<>(deviceIds);
286		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_TRUSTED,
287				XmppAxolotlSession.Trust.TRUSTED);
288		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_UNDECIDED,
289				XmppAxolotlSession.Trust.UNDECIDED);
290		setTrustOnSessions(jid, newDevices, XmppAxolotlSession.Trust.INACTIVE_UNTRUSTED,
291				XmppAxolotlSession.Trust.UNTRUSTED);
292		this.deviceIds.put(jid, deviceIds);
293		mXmppConnectionService.keyStatusUpdated();
294	}
295
296	public void wipeOtherPepDevices() {
297		if (pepBroken) {
298			Log.d(Config.LOGTAG, getLogprefix(account) + "wipeOtherPepDevices called, but PEP is broken. Ignoring... ");
299			return;
300		}
301		Set<Integer> deviceIds = new HashSet<>();
302		deviceIds.add(getOwnDeviceId());
303		IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIds);
304		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Wiping all other devices from Pep:" + publish);
305		mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
306			@Override
307			public void onIqPacketReceived(Account account, IqPacket packet) {
308				// TODO: implement this!
309			}
310		});
311	}
312
313	public void purgeKey(IdentityKey identityKey) {
314		axolotlStore.setFingerprintTrust(identityKey.getFingerprint().replaceAll("\\s", ""), XmppAxolotlSession.Trust.COMPROMISED);
315	}
316
317	public void publishOwnDeviceIdIfNeeded() {
318		if (pepBroken) {
319			Log.d(Config.LOGTAG, getLogprefix(account) + "publishOwnDeviceIdIfNeeded called, but PEP is broken. Ignoring... ");
320			return;
321		}
322		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveDeviceIds(account.getJid().toBareJid());
323		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {
324			@Override
325			public void onIqPacketReceived(Account account, IqPacket packet) {
326				if (packet.getType() == IqPacket.TYPE.TIMEOUT) {
327					Log.d(Config.LOGTAG, getLogprefix(account) + "Timeout received while retrieving own Device Ids.");
328				} else {
329					Element item = mXmppConnectionService.getIqParser().getItem(packet);
330					Set<Integer> deviceIds = mXmppConnectionService.getIqParser().deviceIds(item);
331					if (!deviceIds.contains(getOwnDeviceId())) {
332						publishOwnDeviceId(deviceIds);
333					}
334				}
335			}
336		});
337	}
338
339	public void publishOwnDeviceId(Set<Integer> deviceIds) {
340		Set<Integer> deviceIdsCopy = new HashSet<>(deviceIds);
341		if (!deviceIdsCopy.contains(getOwnDeviceId())) {
342			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Own device " + getOwnDeviceId() + " not in PEP devicelist.");
343			if (deviceIdsCopy.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			deviceIdsCopy.add(getOwnDeviceId());
356			IqPacket publish = mXmppConnectionService.getIqGenerator().publishDeviceIds(deviceIdsCopy);
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(final boolean announceAfter) {
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				PreKeyBundle bundle = mXmppConnectionService.getIqParser().bundle(packet);
378				Map<Integer, ECPublicKey> keys = mXmppConnectionService.getIqParser().preKeyPublics(packet);
379				boolean flush = false;
380				if (bundle == null) {
381					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid bundle:" + packet);
382					bundle = new PreKeyBundle(-1, -1, -1, null, -1, null, null, null);
383					flush = true;
384				}
385				if (keys == null) {
386					Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received invalid prekeys:" + packet);
387				}
388				try {
389					boolean changed = false;
390					// Validate IdentityKey
391					IdentityKeyPair identityKeyPair = axolotlStore.getIdentityKeyPair();
392					if (flush || !identityKeyPair.getPublicKey().equals(bundle.getIdentityKey())) {
393						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding own IdentityKey " + identityKeyPair.getPublicKey() + " to PEP.");
394						changed = true;
395					}
396
397					// Validate signedPreKeyRecord + ID
398					SignedPreKeyRecord signedPreKeyRecord;
399					int numSignedPreKeys = axolotlStore.loadSignedPreKeys().size();
400					try {
401						signedPreKeyRecord = axolotlStore.loadSignedPreKey(bundle.getSignedPreKeyId());
402						if (flush
403								|| !bundle.getSignedPreKey().equals(signedPreKeyRecord.getKeyPair().getPublicKey())
404								|| !Arrays.equals(bundle.getSignedPreKeySignature(), signedPreKeyRecord.getSignature())) {
405							Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
406							signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
407							axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
408							changed = true;
409						}
410					} catch (InvalidKeyIdException e) {
411						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding new signedPreKey with ID " + (numSignedPreKeys + 1) + " to PEP.");
412						signedPreKeyRecord = KeyHelper.generateSignedPreKey(identityKeyPair, numSignedPreKeys + 1);
413						axolotlStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
414						changed = true;
415					}
416
417					// Validate PreKeys
418					Set<PreKeyRecord> preKeyRecords = new HashSet<>();
419					if (keys != null) {
420						for (Integer id : keys.keySet()) {
421							try {
422								PreKeyRecord preKeyRecord = axolotlStore.loadPreKey(id);
423								if (preKeyRecord.getKeyPair().getPublicKey().equals(keys.get(id))) {
424									preKeyRecords.add(preKeyRecord);
425								}
426							} catch (InvalidKeyIdException ignored) {
427							}
428						}
429					}
430					int newKeys = NUM_KEYS_TO_PUBLISH - preKeyRecords.size();
431					if (newKeys > 0) {
432						List<PreKeyRecord> newRecords = KeyHelper.generatePreKeys(
433								axolotlStore.getCurrentPreKeyId() + 1, newKeys);
434						preKeyRecords.addAll(newRecords);
435						for (PreKeyRecord record : newRecords) {
436							axolotlStore.storePreKey(record.getId(), record);
437						}
438						changed = true;
439						Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Adding " + newKeys + " new preKeys to PEP.");
440					}
441
442
443					if (changed) {
444						IqPacket publish = mXmppConnectionService.getIqGenerator().publishBundles(
445								signedPreKeyRecord, axolotlStore.getIdentityKeyPair().getPublicKey(),
446								preKeyRecords, getOwnDeviceId());
447						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + ": Bundle " + getOwnDeviceId() + " in PEP not current. Publishing: " + publish);
448						mXmppConnectionService.sendIqPacket(account, publish, new OnIqPacketReceived() {
449							@Override
450							public void onIqPacketReceived(Account account, IqPacket packet) {
451								if (packet.getType() == IqPacket.TYPE.RESULT) {
452									Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Successfully published bundle. ");
453									if (announceAfter) {
454										Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
455										publishOwnDeviceIdIfNeeded();
456									}
457								} else {
458									Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while publishing bundle: " + packet.findChild("error"));
459								}
460							}
461						});
462					} else {
463						Log.d(Config.LOGTAG, getLogprefix(account) + "Bundle " + getOwnDeviceId() + " in PEP was current");
464						if (announceAfter) {
465							Log.d(Config.LOGTAG, getLogprefix(account) + "Announcing device " + getOwnDeviceId());
466							publishOwnDeviceIdIfNeeded();
467						}
468					}
469				} catch (InvalidKeyException e) {
470					Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Failed to publish bundle " + getOwnDeviceId() + ", reason: " + e.getMessage());
471					return;
472				}
473			}
474		});
475	}
476
477	public boolean isContactAxolotlCapable(Contact contact) {
478
479		Jid jid = contact.getJid().toBareJid();
480		AxolotlAddress address = new AxolotlAddress(jid.toString(), 0);
481		return sessions.hasAny(address) ||
482				(deviceIds.containsKey(jid) && !deviceIds.get(jid).isEmpty());
483	}
484
485	public XmppAxolotlSession.Trust getFingerprintTrust(String fingerprint) {
486		return axolotlStore.getFingerprintTrust(fingerprint);
487	}
488
489	public void setFingerprintTrust(String fingerprint, XmppAxolotlSession.Trust trust) {
490		axolotlStore.setFingerprintTrust(fingerprint, trust);
491	}
492
493	private void buildSessionFromPEP(final AxolotlAddress address) {
494		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building new sesstion for " + address.toString());
495		if (address.getDeviceId() == getOwnDeviceId()) {
496			throw new AssertionError("We should NEVER build a session with ourselves. What happened here?!");
497		}
498
499		try {
500			IqPacket bundlesPacket = mXmppConnectionService.getIqGenerator().retrieveBundlesForDevice(
501					Jid.fromString(address.getName()), address.getDeviceId());
502			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Retrieving bundle: " + bundlesPacket);
503			mXmppConnectionService.sendIqPacket(account, bundlesPacket, new OnIqPacketReceived() {
504				private void finish() {
505					AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
506					if (!fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
507							&& !fetchStatusMap.getAll(address).containsValue(FetchStatus.PENDING)) {
508						mXmppConnectionService.keyStatusUpdated();
509					}
510				}
511
512				@Override
513				public void onIqPacketReceived(Account account, IqPacket packet) {
514					if (packet.getType() == IqPacket.TYPE.RESULT) {
515						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Received preKey IQ packet, processing...");
516						final IqParser parser = mXmppConnectionService.getIqParser();
517						final List<PreKeyBundle> preKeyBundleList = parser.preKeys(packet);
518						final PreKeyBundle bundle = parser.bundle(packet);
519						if (preKeyBundleList.isEmpty() || bundle == null) {
520							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "preKey IQ packet invalid: " + packet);
521							fetchStatusMap.put(address, FetchStatus.ERROR);
522							finish();
523							return;
524						}
525						Random random = new Random();
526						final PreKeyBundle preKey = preKeyBundleList.get(random.nextInt(preKeyBundleList.size()));
527						if (preKey == null) {
528							//should never happen
529							fetchStatusMap.put(address, FetchStatus.ERROR);
530							finish();
531							return;
532						}
533
534						final PreKeyBundle preKeyBundle = new PreKeyBundle(0, address.getDeviceId(),
535								preKey.getPreKeyId(), preKey.getPreKey(),
536								bundle.getSignedPreKeyId(), bundle.getSignedPreKey(),
537								bundle.getSignedPreKeySignature(), bundle.getIdentityKey());
538
539						try {
540							SessionBuilder builder = new SessionBuilder(axolotlStore, address);
541							builder.process(preKeyBundle);
542							XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, bundle.getIdentityKey().getFingerprint().replaceAll("\\s", ""));
543							sessions.put(address, session);
544							fetchStatusMap.put(address, FetchStatus.SUCCESS);
545						} catch (UntrustedIdentityException | InvalidKeyException e) {
546							Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Error building session for " + address + ": "
547									+ e.getClass().getName() + ", " + e.getMessage());
548							fetchStatusMap.put(address, FetchStatus.ERROR);
549						}
550
551						finish();
552					} else {
553						fetchStatusMap.put(address, FetchStatus.ERROR);
554						Log.d(Config.LOGTAG, getLogprefix(account) + "Error received while building session:" + packet.findChild("error"));
555						finish();
556						return;
557					}
558				}
559			});
560		} catch (InvalidJidException e) {
561			Log.e(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Got address with invalid jid: " + address.getName());
562		}
563	}
564
565	public Set<AxolotlAddress> findDevicesWithoutSession(final Conversation conversation) {
566		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Finding devices without session for " + conversation.getContact().getJid().toBareJid());
567		Jid contactJid = conversation.getContact().getJid().toBareJid();
568		Set<AxolotlAddress> addresses = new HashSet<>();
569		if (deviceIds.get(contactJid) != null) {
570			for (Integer foreignId : this.deviceIds.get(contactJid)) {
571				AxolotlAddress address = new AxolotlAddress(contactJid.toString(), foreignId);
572				if (sessions.get(address) == null) {
573					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
574					if (identityKey != null) {
575						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
576						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey.getFingerprint().replaceAll("\\s", ""));
577						sessions.put(address, session);
578					} else {
579						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + account.getJid().toBareJid() + ":" + foreignId);
580						addresses.add(new AxolotlAddress(contactJid.toString(), foreignId));
581					}
582				}
583			}
584		} else {
585			Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Have no target devices in PEP!");
586		}
587		if (deviceIds.get(account.getJid().toBareJid()) != null) {
588			for (Integer ownId : this.deviceIds.get(account.getJid().toBareJid())) {
589				AxolotlAddress address = new AxolotlAddress(account.getJid().toBareJid().toString(), ownId);
590				if (sessions.get(address) == null) {
591					IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
592					if (identityKey != null) {
593						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already have session for " + address.toString() + ", adding to cache...");
594						XmppAxolotlSession session = new XmppAxolotlSession(account, axolotlStore, address, identityKey.getFingerprint().replaceAll("\\s", ""));
595						sessions.put(address, session);
596					} else {
597						Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Found device " + account.getJid().toBareJid() + ":" + ownId);
598						addresses.add(new AxolotlAddress(account.getJid().toBareJid().toString(), ownId));
599					}
600				}
601			}
602		}
603
604		return addresses;
605	}
606
607	public boolean createSessionsIfNeeded(final Conversation conversation) {
608		Log.i(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Creating axolotl sessions if needed...");
609		boolean newSessions = false;
610		Set<AxolotlAddress> addresses = findDevicesWithoutSession(conversation);
611		for (AxolotlAddress address : addresses) {
612			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Processing device: " + address.toString());
613			FetchStatus status = fetchStatusMap.get(address);
614			if (status == null || status == FetchStatus.ERROR) {
615				fetchStatusMap.put(address, FetchStatus.PENDING);
616				this.buildSessionFromPEP(address);
617				newSessions = true;
618			} else if (status == FetchStatus.PENDING) {
619				newSessions = true;
620			} else {
621				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Already fetching bundle for " + address.toString());
622			}
623		}
624
625		return newSessions;
626	}
627
628	public boolean hasPendingKeyFetches(Conversation conversation) {
629		AxolotlAddress ownAddress = new AxolotlAddress(account.getJid().toBareJid().toString(), 0);
630		AxolotlAddress foreignAddress = new AxolotlAddress(conversation.getJid().toBareJid().toString(), 0);
631		return fetchStatusMap.getAll(ownAddress).containsValue(FetchStatus.PENDING)
632				|| fetchStatusMap.getAll(foreignAddress).containsValue(FetchStatus.PENDING);
633
634	}
635
636	@Nullable
637	private XmppAxolotlMessage buildHeader(Contact contact) {
638		final XmppAxolotlMessage axolotlMessage = new XmppAxolotlMessage(
639				contact.getJid().toBareJid(), getOwnDeviceId());
640
641		Set<XmppAxolotlSession> contactSessions = findSessionsforContact(contact);
642		Set<XmppAxolotlSession> ownSessions = findOwnSessions();
643		if (contactSessions.isEmpty()) {
644			return null;
645		}
646		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building axolotl foreign keyElements...");
647		for (XmppAxolotlSession session : contactSessions) {
648			Log.v(Config.LOGTAG, AxolotlService.getLogprefix(account) + session.getRemoteAddress().toString());
649			axolotlMessage.addDevice(session);
650		}
651		Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Building axolotl own keyElements...");
652		for (XmppAxolotlSession session : ownSessions) {
653			Log.v(Config.LOGTAG, AxolotlService.getLogprefix(account) + session.getRemoteAddress().toString());
654			axolotlMessage.addDevice(session);
655		}
656
657		return axolotlMessage;
658	}
659
660	@Nullable
661	public XmppAxolotlMessage encrypt(Message message) {
662		XmppAxolotlMessage axolotlMessage = buildHeader(message.getContact());
663
664		if (axolotlMessage != null) {
665			final String content;
666			if (message.hasFileOnRemoteHost()) {
667				content = message.getFileParams().url.toString();
668			} else {
669				content = message.getBody();
670			}
671			try {
672				axolotlMessage.encrypt(content);
673			} catch (CryptoFailedException e) {
674				Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to encrypt message: " + e.getMessage());
675				return null;
676			}
677		}
678
679		return axolotlMessage;
680	}
681
682	public void preparePayloadMessage(final Message message, final boolean delay) {
683		executor.execute(new Runnable() {
684			@Override
685			public void run() {
686				XmppAxolotlMessage axolotlMessage = encrypt(message);
687				if (axolotlMessage == null) {
688					mXmppConnectionService.markMessage(message, Message.STATUS_SEND_FAILED);
689					//mXmppConnectionService.updateConversationUi();
690				} else {
691					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Generated message, caching: " + message.getUuid());
692					messageCache.put(message.getUuid(), axolotlMessage);
693					mXmppConnectionService.resendMessage(message, delay);
694				}
695			}
696		});
697	}
698
699	public void prepareKeyTransportMessage(final Contact contact, final OnMessageCreatedCallback onMessageCreatedCallback) {
700		executor.execute(new Runnable() {
701			@Override
702			public void run() {
703				XmppAxolotlMessage axolotlMessage = buildHeader(contact);
704				onMessageCreatedCallback.run(axolotlMessage);
705			}
706		});
707	}
708
709	public XmppAxolotlMessage fetchAxolotlMessageFromCache(Message message) {
710		XmppAxolotlMessage axolotlMessage = messageCache.get(message.getUuid());
711		if (axolotlMessage != null) {
712			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache hit: " + message.getUuid());
713			messageCache.remove(message.getUuid());
714		} else {
715			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Cache miss: " + message.getUuid());
716		}
717		return axolotlMessage;
718	}
719
720	private XmppAxolotlSession recreateUncachedSession(AxolotlAddress address) {
721		IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
722		return (identityKey != null)
723				? new XmppAxolotlSession(account, axolotlStore, address,
724						identityKey.getFingerprint().replaceAll("\\s", ""))
725				: null;
726	}
727
728	private XmppAxolotlSession getReceivingSession(XmppAxolotlMessage message) {
729		AxolotlAddress senderAddress = new AxolotlAddress(message.getFrom().toString(),
730				message.getSenderDeviceId());
731		XmppAxolotlSession session = sessions.get(senderAddress);
732		if (session == null) {
733			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account) + "Account: " + account.getJid() + " No axolotl session found while parsing received message " + message);
734			session = recreateUncachedSession(senderAddress);
735			if (session == null) {
736				session = new XmppAxolotlSession(account, axolotlStore, senderAddress);
737			}
738		}
739		return session;
740	}
741
742	public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message) {
743		XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = null;
744
745		XmppAxolotlSession session = getReceivingSession(message);
746		try {
747			plaintextMessage = message.decrypt(session, getOwnDeviceId());
748			Integer preKeyId = session.getPreKeyId();
749			if (preKeyId != null) {
750				publishBundlesIfNeeded(false);
751				session.resetPreKeyId();
752			}
753		} catch (CryptoFailedException e) {
754			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message: " + e.getMessage());
755		}
756
757		if (session.isFresh() && plaintextMessage != null) {
758			sessions.put(session);
759		}
760
761		return plaintextMessage;
762	}
763
764	public XmppAxolotlMessage.XmppAxolotlKeyTransportMessage processReceivingKeyTransportMessage(XmppAxolotlMessage message) {
765		XmppAxolotlMessage.XmppAxolotlKeyTransportMessage keyTransportMessage = null;
766
767		XmppAxolotlSession session = getReceivingSession(message);
768		keyTransportMessage = message.getParameters(session, getOwnDeviceId());
769
770		if (session.isFresh() && keyTransportMessage != null) {
771			sessions.put(session);
772		}
773
774		return keyTransportMessage;
775	}
776}