feat: extended IRegistry interface (no breaking changes). VM detection is broken regardless

SafeExamBrowser.Runtime/CompositionRoot.cs

@@ -83,7 +83,7 @@ namespace SafeExamBrowser.Runtime
 			var serviceProxy = new ServiceProxy(appConfig.ServiceAddress, new ProxyObjectFactory(), ModuleLogger(nameof(ServiceProxy)), Interlocutor.Runtime);
 			var sessionContext = new SessionContext();
 			var splashScreen = uiFactory.CreateSplashScreen(appConfig);
-			var vmDetector = new VirtualMachineDetector(ModuleLogger(nameof(VirtualMachineDetector)), systemInfo);
+			var vmDetector = new VirtualMachineDetector(ModuleLogger(nameof(VirtualMachineDetector)), registry, systemInfo);
 
 			var bootstrapOperations = new Queue<IOperation>();
 			var sessionOperations = new Queue<IRepeatableOperation>();

SafeExamBrowser.SystemComponents.Contracts/Registry/IRegistry.cs

@@ -7,6 +7,7 @@
  */
 
 using SafeExamBrowser.SystemComponents.Contracts.Registry.Events;
+using System.Collections.Generic;
 
 namespace SafeExamBrowser.SystemComponents.Contracts.Registry
 {
@@ -34,5 +35,15 @@ namespace SafeExamBrowser.SystemComponents.Contracts.Registry
 		/// Attempts to read the value of the given name under the specified registry key.
 		/// </summary>
 		bool TryRead(string key, string name, out object value);
+
+		/// <summary>
+		/// Attempts to read the value names of the given registry key.
+		/// </summary>
+		bool TryGetNames(string key, out IEnumerable<string> names);
+
+		/// <summary>
+		/// Attempts to read the subkey names of the given registry key.
+		/// </summary>
+		bool TryGetSubKeys(string key, out IEnumerable<string> subKeys);
 	}
 }

SafeExamBrowser.SystemComponents/Registry/Registry.cs

@@ -8,7 +8,10 @@
 
 using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Security.Cryptography;
 using System.Timers;
+using Microsoft.Win32;
 using SafeExamBrowser.Logging.Contracts;
 using SafeExamBrowser.SystemComponents.Contracts.Registry;
 using SafeExamBrowser.SystemComponents.Contracts.Registry.Events;
@@ -86,6 +89,38 @@ namespace SafeExamBrowser.SystemComponents.Registry
 			return success;
 		}
 
+		public bool TryGetNames(string key, out IEnumerable<string> names)
+		{
+			names = null;
+
+			RegistryKey keyObj;
+			if (!TryOpenKey(key, out keyObj))
+				return false;
+
+			using (keyObj)
+			{
+				names = keyObj.GetValueNames();
+			}
+
+			return true;
+		}
+
+		public bool TryGetSubKeys(string key, out IEnumerable<string> subKeys)
+		{
+			subKeys = null;
+
+			RegistryKey keyObj;
+			if (!TryOpenKey(key, out keyObj))
+				return false;
+
+			using (keyObj)
+			{
+				subKeys = keyObj.GetSubKeyNames();
+			}
+
+			return true;
+		}
+
 		private void Timer_Elapsed(object sender, ElapsedEventArgs e)
 		{
 			foreach (var item in values)
@@ -104,5 +139,104 @@ namespace SafeExamBrowser.SystemComponents.Registry
 				}
 			}
 		}
+
+		/// <summary>
+		/// Parses a keyName and returns the basekey for it.
+		/// It will also store the subkey name in the out parameter.
+		/// If the keyName is not valid, we will return false.
+		/// Does not raise Exceptions.
+		/// Supports shortcuts.
+		/// </summary>
+		// yoinked (and partially modified to follow SEB conventions) private Win32 function: https://stackoverflow.com/a/58547945
+		private bool GetBaseKeyFromKeyName(string keyName, out RegistryKey hiveKey, out string subKeyName)
+		{
+			hiveKey = null;
+			subKeyName = null;
+
+			string basekeyName;
+			int i = keyName.IndexOf('\\');
+			if (i != -1)
+			{
+				basekeyName = keyName.Substring(0, i).ToUpper(System.Globalization.CultureInfo.InvariantCulture);
+			}
+			else
+			{
+				basekeyName = keyName.ToUpper(System.Globalization.CultureInfo.InvariantCulture);
+			}
+
+			// add shortcuts as well to be implicit
+			switch (basekeyName)
+			{
+				case "HKEY_CURRENT_USER":
+				case "HKCU":
+					hiveKey = RegistryKey.OpenBaseKey(RegistryHive.CurrentUser, RegistryView.Registry64);
+					break;
+				case "HKEY_LOCAL_MACHINE":
+				case "HKLM":
+					hiveKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64);
+					break;
+				case "HKEY_CLASSES_ROOT":
+				case "HKCR":
+					hiveKey = RegistryKey.OpenBaseKey(RegistryHive.ClassesRoot, RegistryView.Registry64);
+					break;
+				case "HKEY_USERS":
+				case "HKU":
+					hiveKey = RegistryKey.OpenBaseKey(RegistryHive.Users, RegistryView.Registry64);
+					break;
+				case "HKEY_PERFORMANCE_DATA":
+				case "HKPD":
+					hiveKey = RegistryKey.OpenBaseKey(RegistryHive.PerformanceData, RegistryView.Registry64);
+					break;
+				case "HKEY_CURRENT_CONFIG":
+				case "HKCC":
+					hiveKey = RegistryKey.OpenBaseKey(RegistryHive.CurrentConfig, RegistryView.Registry64);
+					break;
+				case "HKEY_DYN_DATA":
+				case "HKDD":
+					hiveKey = RegistryKey.OpenBaseKey(RegistryHive.DynData, RegistryView.Registry64);
+					break;
+				default:
+					// output is already set to null at the start
+					return false;
+			}
+
+			if (i == -1 || i == keyName.Length)
+			{
+				subKeyName = string.Empty;
+			}
+			else
+			{
+				subKeyName = keyName.Substring(i + 1, keyName.Length - i - 1);
+			}
+
+			return true;
+		}
+
+		/// <summary>
+		/// Tries to open a key and outputs a RegistryKey object. Does not raise Exceptions, but returns false/true.
+		/// </summary>
+		private bool TryOpenKey(string key, out RegistryKey keyObj)
+		{
+			keyObj = null;
+
+			string subHiveKey;
+			try
+			{
+				RegistryKey hiveObj;
+				if (!GetBaseKeyFromKeyName(key, out hiveObj, out subHiveKey))
+					return false;
+
+				keyObj = hiveObj.OpenSubKey(subHiveKey);
+				if (keyObj == null)
+					return false;
+			}
+			catch (Exception e)
+			{
+				logger.Error($"Failed to open registry key '{key}'!", e);
+				return false;
+			}
+
+			return true;
+		}
 	}
 }

SafeExamBrowser.SystemComponents/VirtualMachineDetector.cs

@@ -10,7 +10,11 @@ using System.Linq;
 using System.Management;
 using SafeExamBrowser.Logging.Contracts;
 using SafeExamBrowser.SystemComponents.Contracts;
+using SafeExamBrowser.SystemComponents.Contracts.Registry;
 using Microsoft.Win32;
+using System.Collections;
+using System.Collections.Generic;
+using System;
 
 namespace SafeExamBrowser.SystemComponents
 {
@@ -31,11 +35,13 @@ namespace SafeExamBrowser.SystemComponents
 		private static readonly string VIRTUALBOX_MAC_PREFIX = "080027";
 
 		private readonly ILogger logger;
+		private readonly IRegistry registry;
 		private readonly ISystemInfo systemInfo;
 
-		public VirtualMachineDetector(ILogger logger, ISystemInfo systemInfo)
+		public VirtualMachineDetector(ILogger logger, IRegistry registry, ISystemInfo systemInfo)
 		{
 			this.logger = logger;
+			this.registry = registry; 
 			this.systemInfo = systemInfo;
 		}
 
@@ -97,45 +103,70 @@ namespace SafeExamBrowser.SystemComponents
 		{
 			var isVirtualMachine = false;
 
-			// check historic hardware profiles
+			/** 
-			var hardwareConfKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey("SYSTEM\\HardwareConfig");
+			 * check historic hardware profiles
-			if (hardwareConfKey != null)
+			 * 
+			 * HKLM\SYSTEM\HardwareConfig\{configId=uuid}\ComputerIds
+			 *	- {computerId=uuid}: {computerSummary=hardwareInfo}
+			 *	
+			 */
+			IEnumerable<string> hardwareConfigSubkeys;
+			if (!registry.TryGetSubKeys("HKLM\\SYSTEM\\HardwareConfig", out hardwareConfigSubkeys))
+				return false;
+
+			foreach (string configId in hardwareConfigSubkeys)
 			{
-				foreach (string configId in hardwareConfKey.GetSubKeyNames())
+				logger.Info($"scanning configId: {configId}");
+				var configKey = $"HKEY_LOCAL_MACHINE\\SYSTEM\\HardwareConfig\\{configId}";
+
+				object biosVendor;
+				object biosVersion;
+				object systemManufacturer;
+				object systemProductName;
+
+				bool success = true;
+
+				success &= registry.TryRead(configKey, "BIOSVendor", out biosVendor);
+				success &= registry.TryRead(configKey, "BIOSVersion", out biosVersion);
+				success &= registry.TryRead(configKey, "SystemManufacturer", out systemManufacturer);
+				success &= registry.TryRead(configKey, "SystemProductName", out systemProductName);
+
+				if (!success)
+					continue;
+
+				// reconstruct the systemInfo.biosInfo string
+				string biosInfo = $"{(string) biosVendor} {(string) biosVersion}";
+
+				isVirtualMachine |= IsVirtualSystemInfo(biosInfo, (string) systemManufacturer, (string) systemProductName);
+
+				// hardware information of profile throughout installation etc. 
+				IEnumerable<string> computerIds;
+				if (!registry.TryGetSubKeys($"HKLM\\SYSTEM\\HardwareConfig\\{configId}\\ComputerIds", out computerIds))
+					return false;
+
+				foreach (var computerId in computerIds)
 				{
-					var configKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey($"SYSTEM\\HardwareConfig\\{configId}");
+					logger.Info($"computerId: {computerId}");
+					// e.g. manufacturer&version&sku&...
+					object computerSummary; // = (string) computerIds.GetValue(computerId);
 
-					if (configKey == null)
+					if (!registry.TryRead($"HKLM\\SYSTEM\\HardwareConfig\\{configId}\\ComputerIds", computerId, out computerSummary))
-					{
 						continue;
-					}
 
-					// reconstruct the systemInfo.biosInfo string
+					isVirtualMachine |= IsVirtualSystemInfo((string) computerSummary, (string) systemManufacturer, (string) systemProductName);
-					var biosInfo = (string) configKey.GetValue("BIOSVendor") + " " + (string) configKey.GetValue("BIOSVersion");
-					var manufacturer = (string) configKey.GetValue("SystemManufacturer");
-					var model = (string) configKey.GetValue("SystemProductName");
-
-					isVirtualMachine |= IsVirtualSystemInfo(biosInfo, manufacturer, model);
-
-					// hardware information of profile throughout installation etc. 
-					var computerIdsKey = Microsoft.Win32.Registry.LocalMachine.OpenSubKey($"SYSTEM\\HardwareConfig\\{configId}\\ComputerIds");
-
-					if (computerIdsKey == null)
-					{
-						continue;
-					}
-
-					foreach (var computerId in computerIdsKey.GetSubKeyNames())
-					{
-						// e.g. manufacturer&version&sku&...
-						var computerSummary = (string) computerIdsKey.GetValue(computerId);
-						isVirtualMachine |= IsVirtualSystemInfo(computerSummary, computerSummary, computerSummary);
-					}
 				}
 			}
 
 			// check Windows timeline caches for current hardware config
-			var deviceCacheKey = Microsoft.Win32.Registry.CurrentUser.OpenSubKey($"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\TaskFlow\\DeviceCache");
+			/*IEnumerable<string> deviceCacheSubkeys;
+			if (registry.TryGetSubKeys($"HKCU\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\TaskFlow\\DeviceCache", out deviceCacheSubkeys)
+			{
+				foreach (string deviceCacheKey in deviceCacheSubkeys)
+				{
+					if (registry.TryRead($"HKCU\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\TaskFlow\\DeviceCache"))*/
+
+
+			var deviceCacheKey = Microsoft.Win32.Registry.CurrentUser.OpenSubKey($"HKCU\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\TaskFlow\\DeviceCache");
 			var currHostname = System.Environment.GetEnvironmentVariable("COMPUTERNAME");
 
 			if (deviceCacheKey != null && currHostname != null)