Restore SEBPatch

SafeExamBrowser.Runtime/Operations/SessionIntegrityOperation.cs

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+/*
+ * Copyright (c) 2024 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.Core.Contracts.OperationModel;
+using SafeExamBrowser.Core.Contracts.OperationModel.Events;
+using SafeExamBrowser.I18n.Contracts;
+using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.Monitoring.Contracts.System;
+
+namespace SafeExamBrowser.Runtime.Operations
+{
+	internal class SessionIntegrityOperation : SessionOperation
+	{
+		private readonly ILogger logger;
+		private readonly ISystemSentinel sentinel;
+
+		public override event ActionRequiredEventHandler ActionRequired { add { } remove { } }
+		public override event StatusChangedEventHandler StatusChanged;
+
+		public SessionIntegrityOperation(ILogger logger, ISystemSentinel sentinel, SessionContext context) : base(context)
+		{
+			this.logger = logger;
+			this.sentinel = sentinel;
+		}
+
+		public override OperationResult Perform()
+		{
+			var success = true;
+
+			StatusChanged?.Invoke(TextKey.OperationStatus_VerifySessionIntegrity);
+
+			success &= InitializeStickyKeys();
+			success &= VerifyCursors();
+			success &= VerifyEaseOfAccess();
+
+			LogResult(success);
+
+			return success ? OperationResult.Success : OperationResult.Failed;
+		}
+
+		public override OperationResult Repeat()
+		{
+			var success = true;
+
+			StatusChanged?.Invoke(TextKey.OperationStatus_VerifySessionIntegrity);
+
+			success &= InitializeStickyKeys();
+			success &= VerifyCursors();
+			success &= VerifyEaseOfAccess();
+
+			LogResult(success);
+
+			return success ? OperationResult.Success : OperationResult.Failed;
+		}
+
+		public override OperationResult Revert()
+		{
+			FinalizeStickyKeys();
+
+			return OperationResult.Success;
+		}
+
+		private void FinalizeStickyKeys()
+		{
+			sentinel.RevertStickyKeys();
+		}
+
+		private bool InitializeStickyKeys()
+		{
+			var success = true;
+
+			sentinel.RevertStickyKeys();
+
+			if (!Context.Next.Settings.Security.AllowStickyKeys)
+			{
+				success = sentinel.DisableStickyKeys();
+			}
+
+			return success;
+		}
+
+		private void LogResult(bool success)
+		{
+			if (success)
+			{
+				logger.Info("Successfully ensured session integrity.");
+			}
+			else
+			{
+				logger.Error("Failed to ensure session integrity! Aborting session initialization...");
+			}
+		}
+
+		private bool VerifyCursors()
+		{
+			var success = true;
+
+			if (Context.Next.Settings.Security.VerifyCursorConfiguration)
+			{
+				success = sentinel.VerifyCursors();
+			}
+			else
+			{
+				logger.Debug("Verification of cursor configuration is disabled.");
+			}
+
+			return success;
+		}
+
+		private bool VerifyEaseOfAccess()
+		{
+			var success = sentinel.VerifyEaseOfAccess();
+
+			if (!success)
+			{
+				if (Context.Current?.Settings.Service.IgnoreService == false)
+				{
+					logger.Info($"Ease of access configuration is compromised but service was active in the current session.");
+					success = true;
+				}
+				else if (!Context.Next.Settings.Service.IgnoreService)
+				{
+					logger.Info($"Ease of access configuration is compromised but service will be active in the next session.");
+					success = true;
+				}
+			}
+
+			return success;
+		}
+	}
+}