Update Safe Exam Browser Patch to 3.10.0.826

SafeExamBrowser.UserInterface.Shared/Guardable.cs

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 ETH Zürich, IT Services
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using SafeExamBrowser.UserInterface.Contracts;
+
+namespace SafeExamBrowser.UserInterface.Shared
+{
+	public abstract class Guardable
+	{
+		private readonly IWindowGuard windowGuard;
+
+		public Guardable(IWindowGuard windowGuard = default)
+		{
+			this.windowGuard = windowGuard;
+		}
+
+		protected T Guard<T>(T window)
+		{
+			windowGuard?.Register(window);
+
+			return window;
+		}
+	}
+}

SafeExamBrowser.UserInterface.Shared/SafeExamBrowser.UserInterface.Shared.csproj

@@ -71,6 +71,7 @@
     <Compile Include="Activators\TaskviewKeyboardActivator.cs" />
     <Compile Include="Activators\TerminationActivator.cs" />
     <Compile Include="Activators\TouchActivator.cs" />
+    <Compile Include="Guardable.cs" />
     <Compile Include="Properties\AssemblyInfo.cs">
       <SubType>Code</SubType>
     </Compile>
@@ -80,6 +81,7 @@
     <Compile Include="Utilities\Thumbnail.cs" />
     <Compile Include="Utilities\VisualExtensions.cs" />
     <Compile Include="Utilities\WindowExtensions.cs" />
+    <Compile Include="WindowGuard.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\SafeExamBrowser.Core.Contracts\SafeExamBrowser.Core.Contracts.csproj">

SafeExamBrowser.UserInterface.Shared/Utilities/WindowExtensions.cs

@@ -16,11 +16,12 @@ namespace SafeExamBrowser.UserInterface.Shared.Utilities
 	public static class WindowExtensions
 	{
 		private const int GWL_STYLE = -16;
-		private const uint MF_BYCOMMAND = 0x00000000;
-		private const uint MF_ENABLED = 0x00000000;
-		private const uint MF_GRAYED = 0x00000001;
+		private const uint MF_BYCOMMAND = 0x0;
+		private const uint MF_ENABLED = 0x0;
+		private const uint MF_GRAYED = 0x1;
 		private const uint SC_CLOSE = 0xF060;
-		private const uint SWP_SHOWWINDOW = 0x0040;
+		private const uint SWP_SHOWWINDOW = 0x40;
+		private const uint WDA_EXCLUDEFROMCAPTURE = 0x11;
 		private const int WS_SYSMENU = 0x80000;
 
 		private static readonly IntPtr HWND_BOTTOM = new IntPtr(1);
@@ -47,6 +48,25 @@ namespace SafeExamBrowser.UserInterface.Shared.Utilities
 			}
 		}
 
+		public static bool ExcludeFromCapture(this Window window)
+		{
+			var helper = new WindowInteropHelper(window);
+
+			return SetWindowDisplayAffinity(helper.Handle, WDA_EXCLUDEFROMCAPTURE);
+		}
+
+		public static void ExecuteWithAccess(this Window window, Action action)
+		{
+			if (window.CheckAccess())
+			{
+				action();
+			}
+			else
+			{
+				window.Dispatcher.Invoke(action);
+			}
+		}
+
 		public static void HideCloseButton(this Window window)
 		{
 			var helper = new WindowInteropHelper(window);
@@ -75,6 +95,9 @@ namespace SafeExamBrowser.UserInterface.Shared.Utilities
 		[DllImport("user32.dll")]
 		private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
 
+		[DllImport("user32.dll")]
+		public static extern bool SetWindowDisplayAffinity(IntPtr hwnd, uint dwAffinity);
+
 		[DllImport("user32.dll")]
 		private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
 

SafeExamBrowser.UserInterface.Shared/WindowGuard.cs

@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2025 ETH Zürich, IT Services
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+using System.Collections.Concurrent;
+using System.Linq;
+using System.Windows;
+using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.UserInterface.Contracts;
+using SafeExamBrowser.UserInterface.Shared.Utilities;
+
+namespace SafeExamBrowser.UserInterface.Shared
+{
+	public class WindowGuard : IWindowGuard
+	{
+		private readonly ConcurrentStack<Window> cache;
+		private readonly ILogger logger;
+
+		private bool? active;
+
+		public WindowGuard(ILogger logger)
+		{
+			this.cache = new ConcurrentStack<Window>();
+			this.logger = logger;
+		}
+
+		public void Activate()
+		{
+			active = true;
+
+			while (cache.Any())
+			{
+				if (cache.TryPop(out var window))
+				{
+					Guard(window);
+				}
+			}
+		}
+
+		public void Deactivate()
+		{
+			active = false;
+			cache.Clear();
+		}
+
+		public void Register(object @object)
+		{
+			if (@object is Window window)
+			{
+				window.ExecuteWithAccess(() => window.Loaded += (o, a) => Triage(window));
+			}
+			else
+			{
+				throw new ArgumentException($"The given object '{@object}' is not an application window!", nameof(@object));
+			}
+		}
+
+		private void Guard(Window window)
+		{
+			window.ExecuteWithAccess(() =>
+			{
+				var info = $"{window.GetType().Name}";
+
+				try
+				{
+					var success = window.ExcludeFromCapture();
+
+					if (success)
+					{
+						logger.Debug($"Successfully guarded window '{info}'.");
+					}
+					else
+					{
+						logger.Warn($"Failed to guard window '{info}'!");
+					}
+				}
+				catch (Exception e)
+				{
+					logger.Error($"Failed to guard window '{info}'!", e);
+				}
+			});
+		}
+
+		private void Triage(Window window)
+		{
+			if (active == true)
+			{
+				Guard(window);
+			}
+			else if (!active.HasValue)
+			{
+				cache.Push(window);
+			}
+		}
+	}
+}