Merge pull request #1028 from gymkirchenfeld/master

Ignoring SessionLock/Unlock (suspend and/or lock/unlock) to prevent false redscreens

Author: dbuechel

SafeExamBrowser.Client.UnitTests/Responsibilities/MonitoringResponsibilityTests.cs

@@ -10,6 +10,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Microsoft.Win32;
 using Moq;
 using SafeExamBrowser.Client.Contracts;
 using SafeExamBrowser.Client.Responsibilities;
@@ -363,7 +364,7 @@ public void SystemMonitor_MustShowLockScreenOnSessionSwitch()
 				.Setup(f => f.CreateLockScreen(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IEnumerable<LockScreenOption>>(), It.IsAny<LockScreenSettings>()))
 				.Returns(lockScreen.Object);
 
-			sentinel.Raise(s => s.SessionChanged += null);
+			sentinel.Raise(s => s.SessionChanged += null, SessionSwitchReason.ConsoleDisconnect);
 
 			coordinator.Verify(c => c.RequestSessionLock(), Times.Once);
 			coordinator.Verify(c => c.ReleaseSessionLock(), Times.Once);
@@ -385,7 +386,7 @@ public void SystemMonitor_MustTerminateIfRequestedByUser()
 				.Callback(new Action<string, string, IEnumerable<LockScreenOption>, LockScreenSettings>((message, title, options, settings) => result.OptionId = options.Last().Id))
 				.Returns(lockScreen.Object);
 
-			sentinel.Raise(s => s.SessionChanged += null);
+			sentinel.Raise(s => s.SessionChanged += null, SessionSwitchReason.ConsoleConnect);
 
 			coordinator.Verify(c => c.RequestSessionLock(), Times.Once);
 			coordinator.Verify(c => c.ReleaseSessionLock(), Times.Once);
@@ -406,9 +407,42 @@ public void SystemMonitor_MustDoNothingIfSessionSwitchAllowed()
 				.Setup(f => f.CreateLockScreen(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IEnumerable<LockScreenOption>>(), It.IsAny<LockScreenSettings>()))
 				.Returns(lockScreen.Object);
 
-			sentinel.Raise(s => s.SessionChanged += null);
+			sentinel.Raise(s => s.SessionChanged += null, SessionSwitchReason.ConsoleConnect);
 
 			lockScreen.Verify(l => l.Show(), Times.Never);
 		}
+
+		[TestMethod]
+		public void SystemMonitor_MustDoNothingIfSessionLockUnlockWithoutService()
+		{
+			var lockScreen = new Mock<ILockScreen>();
+
+			settings.Service.IgnoreService = true;
+			lockScreen.Setup(l => l.WaitForResult()).Returns(new LockScreenResult());
+			uiFactory
+				.Setup(f => f.CreateLockScreen(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IEnumerable<LockScreenOption>>(), It.IsAny<LockScreenSettings>()))
+				.Returns(lockScreen.Object);
+
+			sentinel.Raise(s => s.SessionChanged += null, SessionSwitchReason.SessionLock);
+
+			lockScreen.Verify(l => l.Show(), Times.Never);
+		}
+
+		[TestMethod]
+		public void SystemMonitor_MustShowLockscreenIfNotSessionLockUnlockWithoutService()
+		{
+			var lockScreen = new Mock<ILockScreen>();
+
+			settings.Service.IgnoreService = true;
+			coordinator.Setup(c => c.RequestSessionLock()).Returns(true);
+			lockScreen.Setup(l => l.WaitForResult()).Returns(new LockScreenResult());
+			uiFactory
+				.Setup(f => f.CreateLockScreen(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IEnumerable<LockScreenOption>>(), It.IsAny<LockScreenSettings>()))
+				.Returns(lockScreen.Object);
+
+			sentinel.Raise(s => s.SessionChanged += null, SessionSwitchReason.ConsoleConnect);
+
+			lockScreen.Verify(l => l.Show(), Times.Once);
+		}
 	}
 }

SafeExamBrowser.Client/Responsibilities/MonitoringResponsibility.cs

@@ -9,6 +9,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.Win32;
 using SafeExamBrowser.Client.Contracts;
 using SafeExamBrowser.I18n.Contracts;
 using SafeExamBrowser.Logging.Contracts;
@@ -251,18 +252,24 @@ private void Sentinel_EaseOfAccessChanged(SentinelEventArgs args)
 			}
 		}
 
-		private void Sentinel_SessionChanged()
+		private void Sentinel_SessionChanged(SessionSwitchReason reason)
 		{
+			
 			var allow = !Settings.Service.IgnoreService && (!Settings.Service.DisableUserLock || !Settings.Service.DisableUserSwitch);
 			var disable = Settings.Security.DisableSessionChangeLockScreen;
-
+			var isSessionLockEvent = reason == SessionSwitchReason.SessionLock;
+			var isSessionUnlockEvent = reason == SessionSwitchReason.SessionUnlock;
 			if (allow || disable)
 			{
 				Logger.Info($"Detected user session change, but {(allow ? "session locking and/or switching is allowed" : "lock screen is deactivated")}.");
 			}
+			else if (Settings.Service.IgnoreService && (isSessionLockEvent || isSessionUnlockEvent))
+			{
+				Logger.Info($"Detected user session {(isSessionLockEvent ? "lock" : "unlock")}, ignoring!");
+			}
 			else
 			{
-				var message = text.Get(TextKey.LockScreen_UserSessionMessage);
+				var message = text.Get(Settings.Service.IgnoreService ? TextKey.LockScreen_UserSwitchMessage : TextKey.LockScreen_UserSessionMessage);
 				var title = text.Get(TextKey.LockScreen_Title);
 				var continueOption = new LockScreenOption { Text = text.Get(TextKey.LockScreen_UserSessionContinueOption) };
 				var terminateOption = new LockScreenOption { Text = text.Get(TextKey.LockScreen_UserSessionTerminateOption) };

SafeExamBrowser.I18n.Contracts/TextKey.cs

@@ -90,6 +90,7 @@ public enum TextKey
 		LockScreen_UnlockButton,
 		LockScreen_UserSessionContinueOption,
 		LockScreen_UserSessionMessage,
+		LockScreen_UserSwitchMessage,
 		LockScreen_UserSessionTerminateOption,
 		LogWindow_AlwaysOnTop,
 		LogWindow_AutoScroll,

SafeExamBrowser.I18n/Data/de.xml

@@ -228,6 +228,9 @@
     <Entry key="LockScreen_UserSessionMessage">
         Der aktive Benutzer hat sich geändert oder der Computer wurde gesperrt! Bitte wählen Sie eine der verfügbaren Optionen aus und geben Sie das korrekte Passwort ein, um SEB zu entsperren.
     </Entry>
+    <Entry key="LockScreen_UserSwitchMessage">
+        Der aktive Benutzer hat sich geändert! Bitte wählen Sie eine der verfügbaren Optionen aus und geben Sie das korrekte Passwort ein, um SEB zu entsperren.
+    </Entry>
     <Entry key="LockScreen_UserSessionTerminateOption">
         Safe Exam Browser beenden. WARNUNG: Sie werden keine Möglichkeit haben, Daten zu speichern oder weitere Aktionen auszuführen, SEB wird sofort beendet!
     </Entry>

SafeExamBrowser.I18n/Data/en.xml

@@ -228,6 +228,9 @@
     <Entry key="LockScreen_UserSessionMessage">
         The active user has changed or the computer has been locked! In order to unlock SEB, please select one of the available options and enter the correct unlock password.
     </Entry>
+    <Entry key="LockScreen_UserSwitchMessage">
+        The active user has changed. In order to unlock SEB, please select one of the available options and enter the correct unlock password.
+    </Entry>
     <Entry key="LockScreen_UserSessionTerminateOption">
         Terminate Safe Exam Browser. WARNING: There will be no possibility to save data or perform any further actions, the shutdown will be initiated immediately!
     </Entry>

SafeExamBrowser.Monitoring.Contracts/System/Events/SessionChangedEventHandler.cs

@@ -6,10 +6,12 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using Microsoft.Win32;
+
 namespace SafeExamBrowser.Monitoring.Contracts.System.Events
 {
 	/// <summary>
 	/// Indicates that the active user session of the operating system has changed.
 	/// </summary>
-	public delegate void SessionChangedEventHandler();
+	public delegate void SessionChangedEventHandler(SessionSwitchReason reason);
 }

SafeExamBrowser.Monitoring/System/Components/SystemEvents.cs

@@ -81,7 +81,7 @@ private void SystemEvents_SessionEnding(object sender, SessionEndingEventArgs e)
 		private void SystemEvents_SessionChanged(object sender, SessionSwitchEventArgs e)
 		{
 			logger.Info($"User session change detected: {e.Reason}.");
-			Task.Run(() => SessionChanged?.Invoke());
+			Task.Run(() => SessionChanged?.Invoke(e.Reason));
 		}
 
 		private void SystemEvents_TimeChanged(object sender, EventArgs e)

SafeExamBrowser.Monitoring/System/SystemSentinel.cs

@@ -70,7 +70,7 @@ public void StartMonitoringStickyKeys()
 
 		public void StartMonitoringSystemEvents()
 		{
-			systemEvents.SessionChanged += () => SessionChanged?.Invoke();
+			systemEvents.SessionChanged += (reason) => SessionChanged?.Invoke(reason);
 			systemEvents.StartMonitoring();
 		}