Ensure that available sessions are always used

Any time a new session is established, call syncRosterToDisk() to ensure
that on subsequent restoreFromDatabase() calls, the roster is actually
available. This is important so that initAccountServices() can properly
initialize the SessionMap. This prevents a race condition where after
adding a new account and initiating sessions with it, if the app is
killed (e.g. by reinstall) before triggering a syncRosterToDisk(),
subsequent restores will not have the roster available, leading to
missing XmppAxolotlSessions in the SessionMap cache. As a result of
this, a new session was initiated when sending a new message, and
received messages could not be tagged with the originating session's
fingerprint.

As an added sanity check, go to the database to confirm no records are
present before creating fresh XmppAxolotlSession objects (both in the
sending and receiving case).

1 files changed, 30 insertions, 9 deletions

diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
index 6b6c3750..23adbad8 100644
--- a/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
+++ b/src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java
@@ -595,13 +595,17 @@ public class AxolotlService {
 	}
 
 	private static class SessionMap extends AxolotlAddressMap<XmppAxolotlSession> {
+		private final XmppConnectionService xmppConnectionService;
+		private final Account account;
 
-		public SessionMap(SQLiteAxolotlStore store, Account account) {
+		public SessionMap(XmppConnectionService service, SQLiteAxolotlStore store, Account account) {
 			super();
-			this.fillMap(store, account);
+			this.xmppConnectionService = service;
+			this.account = account;
+			this.fillMap(store);
 		}
 
-		private void fillMap(SQLiteAxolotlStore store, Account account) {
+		private void fillMap(SQLiteAxolotlStore store) {
 			for (Contact contact : account.getRoster().getContacts()) {
 				Jid bareJid = contact.getJid().toBareJid();
 				if (bareJid == null) {
@@ -618,6 +622,11 @@ public class AxolotlService {
 			}
 		}
 
+		@Override
+		public void put(AxolotlAddress address, XmppAxolotlSession value) {
+			super.put(address, value);
+			xmppConnectionService.syncRosterToDisk(account);
+		}
 	}
 
 	private static enum FetchStatus {
@@ -640,7 +649,7 @@ public class AxolotlService {
 		this.axolotlStore = new SQLiteAxolotlStore(this.account, this.mXmppConnectionService);
 		this.deviceIds = new HashMap<>();
 		this.messageCache = new HashMap<>();
-		this.sessions = new SessionMap(axolotlStore, account);
+		this.sessions = new SessionMap(mXmppConnectionService, axolotlStore, account);
 		this.fetchStatusMap = new FetchStatusMap();
 		this.executor = new SerialSingleThreadExecutor();
 	}
@@ -933,9 +942,16 @@ public class AxolotlService {
 			FetchStatus status = fetchStatusMap.get(address);
 			XmppAxolotlSession session = sessions.get(address);
 			if ( session == null && ( status == null || status == FetchStatus.ERROR) ) {
-				fetchStatusMap.put(address, FetchStatus.PENDING);
-				this.buildSessionFromPEP(conversation,  address);
-				newSessions = true;
+				IdentityKey identityKey = axolotlStore.loadSession(address).getSessionState().getRemoteIdentityKey();
+				if ( identityKey != null ) {
+					Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account)+"Already have session for " +  address.toString() + ", adding to cache...");
+					session = new XmppAxolotlSession(account, axolotlStore, address, identityKey.getFingerprint().replaceAll("\\s", ""));
+					sessions.put(address, session);
+				} else {
+					fetchStatusMap.put(address, FetchStatus.PENDING);
+					this.buildSessionFromPEP(conversation, address);
+					newSessions = true;
+				}
 			} else {
 				Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account)+"Already have session for " +  address.toString());
 			}
@@ -1022,7 +1038,12 @@ public class AxolotlService {
 		if (session == null) {
 			Log.d(Config.LOGTAG, AxolotlService.getLogprefix(account)+"Account: "+account.getJid()+" No axolotl session found while parsing received message " + message);
 			// TODO: handle this properly
-			session = new XmppAxolotlSession(account, axolotlStore, senderAddress);
+			IdentityKey identityKey = axolotlStore.loadSession(senderAddress).getSessionState().getRemoteIdentityKey();
+			if ( identityKey != null ) {
+				session = new XmppAxolotlSession(account, axolotlStore, senderAddress, identityKey.getFingerprint().replaceAll("\\s", ""));
+			} else {
+				session = new XmppAxolotlSession(account, axolotlStore, senderAddress);
+			}
 			newSession = true;
 		}
 
@@ -1044,7 +1065,7 @@ public class AxolotlService {
 		}
 
 		if (newSession && plaintextMessage != null) {
-			sessions.put(senderAddress,session);
+			sessions.put(senderAddress, session);
 		}
 
 		return plaintextMessage;