disable fingerprint unlock when unlocking fails with invalid key

src/Kp2aBusinessLogic/database/edit/LoadDB.cs

@@ -51,31 +51,41 @@ namespace keepass2android
 		{
 			try
 			{
-				StatusLogger.UpdateMessage(UiStringKey.loading_database);
-				//get the stream data into a single stream variable (databaseStream) regardless whether its preloaded or not:
-				MemoryStream preloadedMemoryStream = _databaseData == null ? null : _databaseData.Result;
-				MemoryStream databaseStream;
-				if (preloadedMemoryStream != null)
-					databaseStream = preloadedMemoryStream;
-				else
+				try
 				{
-					using (Stream s = _app.GetFileStorage(_ioc).OpenFileForRead(_ioc))
-					{
-						databaseStream = new MemoryStream();
-						s.CopyTo(databaseStream);
-						databaseStream.Seek(0, SeekOrigin.Begin);
-					}
-				}
 
-				//ok, try to load the database. Let's start with Kdbx format and retry later if that is the wrong guess:
-				_format = new KdbxDatabaseFormat(KdbpFile.GetFormatToUse(_ioc));
-				TryLoad(databaseStream);
+
+					StatusLogger.UpdateMessage(UiStringKey.loading_database);
+					//get the stream data into a single stream variable (databaseStream) regardless whether its preloaded or not:
+					MemoryStream preloadedMemoryStream = _databaseData == null ? null : _databaseData.Result;
+					MemoryStream databaseStream;
+					if (preloadedMemoryStream != null)
+						databaseStream = preloadedMemoryStream;
+					else
+					{
+						using (Stream s = _app.GetFileStorage(_ioc).OpenFileForRead(_ioc))
+						{
+							databaseStream = new MemoryStream();
+							s.CopyTo(databaseStream);
+							databaseStream.Seek(0, SeekOrigin.Begin);
+						}
+					}
+
+					//ok, try to load the database. Let's start with Kdbx format and retry later if that is the wrong guess:
+					_format = new KdbxDatabaseFormat(KdbpFile.GetFormatToUse(_ioc));
+					TryLoad(databaseStream);
+				}
+				catch (Exception e)
+				{
+					this.Exception = e;
+					throw;
+				}
 			}
 			catch (KeyFileException)
 			{
 				Kp2aLog.Log("KeyFileException");
 				Finish(false, /*TODO Localize: use Keepass error text KPRes.KeyFileError (including "or invalid format")*/
-				       _app.GetResourceString(UiStringKey.keyfile_does_not_exist));
+				       _app.GetResourceString(UiStringKey.keyfile_does_not_exist), Exception);
 			}
 			catch (AggregateException e)
 			{
@@ -86,25 +96,30 @@ namespace keepass2android
 					// Override the message shown with the last (hopefully most recent) inner exception
 					Kp2aLog.Log("Exception: " + innerException);
 				}
-				Finish(false, _app.GetResourceString(UiStringKey.ErrorOcurred) + " " + message);
+				Finish(false, _app.GetResourceString(UiStringKey.ErrorOcurred) + " " + message, Exception);
 				return;
 			}
 			catch (DuplicateUuidsException e)
 			{
 				Kp2aLog.Log("Exception: " + e);
-				Finish(false, _app.GetResourceString(UiStringKey.DuplicateUuidsError)+" " +e.Message+ _app.GetResourceString(UiStringKey.DuplicateUuidsErrorAdditional));
+				Finish(false, _app.GetResourceString(UiStringKey.DuplicateUuidsError) + " " + e.Message + _app.GetResourceString(UiStringKey.DuplicateUuidsErrorAdditional), Exception);
 				return;
 			}
 			catch (Exception e)
 			{
 				Kp2aLog.Log("Exception: " + e);
-				Finish(false, _app.GetResourceString(UiStringKey.ErrorOcurred) + " " + e.Message);
+				Finish(false, _app.GetResourceString(UiStringKey.ErrorOcurred) + " " + e.Message, Exception);
 				return;
 			}
 			
 			
 		}
 
+		/// <summary>
+		/// Holds the exception which was thrown during execution (if any)
+		/// </summary>
+		public Exception Exception { get; set; }
+
 		private void TryLoad(MemoryStream databaseStream)
 		{
 			//create a copy of the stream so we can try again if we get an exception which indicates we should change parameters

src/Kp2aBusinessLogic/database/edit/OnFinish.cs

@@ -26,10 +26,12 @@ namespace keepass2android
 	{
 		protected bool Success;
 		protected String Message;
+		protected Exception Exception;
 		
 		protected OnFinish BaseOnFinish;
 		protected Handler Handler;
 		private ProgressDialogStatusLogger _statusLogger = new ProgressDialogStatusLogger(); //default: no logging but not null -> can be used whenever desired
+		
 
 		public ProgressDialogStatusLogger StatusLogger
 		{
@@ -37,12 +39,11 @@ namespace keepass2android
 			set { _statusLogger = value; }
 		}
 
-		protected OnFinish() {
-		}
 
 		protected OnFinish(Handler handler) {
 			BaseOnFinish = null;
 			Handler = handler;
+			
 		}
 
 		protected OnFinish(OnFinish finish, Handler handler) {
@@ -55,9 +56,10 @@ namespace keepass2android
 			Handler = null;
 		}
 
-		public void SetResult(bool success, String message) {
+		public void SetResult(bool success, string message, Exception exception) {
 			Success = success;
 			Message = message;
+			Exception = exception;
 		}
 		
 		public void SetResult(bool success) {
@@ -67,7 +69,7 @@ namespace keepass2android
 		public virtual void Run() {
 			if (BaseOnFinish == null) return;
 			// Pass on result on call finish
-			BaseOnFinish.SetResult(Success, Message);
+			BaseOnFinish.SetResult(Success, Message, Exception);
 				
 			if ( Handler != null ) {
 				Handler.Post(BaseOnFinish.Run); 

src/Kp2aBusinessLogic/database/edit/RunnableOnFinish.cs

@@ -34,9 +34,9 @@ namespace keepass2android
 			set { _onFinishToRun = value; }
 		}
 
-		protected void Finish(bool result, String message) {
+		protected void Finish(bool result, String message, Exception exception = null) {
 			if ( OnFinishToRun != null ) {
-				OnFinishToRun.SetResult(result, message);
+				OnFinishToRun.SetResult(result, message, exception);
 				OnFinishToRun.Run();
 			}
 		}

src/keepass2android/PasswordActivity.cs

@@ -968,7 +968,7 @@ namespace keepass2android
 				//re-init fingerprint unlock in case something goes wrong with opening the database 
 				InitFingerprintUnlock(); 
 				//fire
-				OnOk();	
+				OnOk(true);	
 			}, 1000);
 
 			
@@ -1138,13 +1138,16 @@ namespace keepass2android
 		    FindViewById<Button>(Resource.Id.change_db).Click += (sender, args) => GoToFileSelectActivity();
 		}
 
-		private void OnOk()
+		private void OnOk(bool usedFingerprintUnlock = false)
 		{
+			UsedFingerprintUnlock = usedFingerprintUnlock;
 			App.Kp2a.GetFileStorage(_ioConnection)
 			   .PrepareFileUsage(new FileStorageSetupInitiatorActivity(this, OnActivityResult, null), _ioConnection,
 			                     RequestCodePrepareDbFile, false);
 		}
 
+		public bool UsedFingerprintUnlock { get; set; }
+
 		private void InitializeTogglePasswordButton()
 		{
 			ImageButton btnTogglePassword = (ImageButton) FindViewById(Resource.Id.toggle_password);
@@ -1932,6 +1935,22 @@ namespace keepass2android
 
 					GC.Collect(); // Ensure temporary memory used while loading is collected
 				}
+
+
+				if (Exception is InvalidCompositeKeyException)
+				{
+					if (_act.UsedFingerprintUnlock)
+					{
+						//disable fingerprint unlock if master password changed
+						_act.ClearFingerprintUnlockData();
+						_act.InitFingerprintUnlock();
+
+						Message = _act.GetString(Resource.String.fingerprint_disabled_wrong_masterkey);
+					}
+					
+
+				}
+				
 				
 				if ((Message != null) && (Message.Length > 150)) //show long messages as dialog
 				{
@@ -1956,7 +1975,7 @@ namespace keepass2android
 						
 
 				}
-				
+
 
 				_act._performingLoad = false;
 

src/keepass2android/Resources/values/strings.xml

@@ -93,6 +93,7 @@
   <string name="enable_fingerprint_quickunlock">Enable Fingerprint Unlock for QuickUnlock</string>
   <string name="fingerprint_unlock_hint">Touch sensor to unlock database</string>
   <string name="fingerprint_unlock_failed">Fingerprint Unlock failed. Decryption key was invalidated by Android OS. This usually happens if a new fingerprint was enrolled or security settings were changed. Please unlock with your password and then re-enabled Fingerprint Unlock in the database settings.</string>
+  <string name="fingerprint_disabled_wrong_masterkey">Unlocking the database failed: Invalid composite key. Fingerprint Unlock was disabled because apparently the stored master password is no longer valid. Please unlock with your password and then re-enabled Fingerprint Unlock in the database settings.</string>
 
   <string name="enable_fingerprint_unlock_Info">
     This will store your master password on this device,