Restore SEBPatch

SafeExamBrowser.Monitoring/VirtualMachineDetector.cs

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024 ETH Zürich, IT Services
+ * 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
@@ -54,11 +54,117 @@ namespace SafeExamBrowser.Monitoring
 
 		public bool IsVirtualMachine()
 		{
+			/*
 			var isVirtualMachine = false;
 
-			logger.Debug($"Computer '{systemInfo.Name}' appears {(isVirtualMachine ? "" : "not ")}to be a virtual machine.");
+			isVirtualMachine |= HasVirtualDevice();
+			isVirtualMachine |= HasVirtualMacAddress();
+			isVirtualMachine |= IsVirtualCpu();
+			isVirtualMachine |= IsVirtualRegistry();
+			isVirtualMachine |= IsVirtualSystem(systemInfo.BiosInfo, systemInfo.Manufacturer, systemInfo.Model);
+			*/
+			logger.Debug($"Computer '{systemInfo.Name}' appears not to be a virtual machine.");
 
-			return isVirtualMachine;
+			return false;
+		}
+
+		private bool HasVirtualDevice()
+		{
+			var hasVirtualDevice = false;
+
+			foreach (var device in systemInfo.PlugAndPlayDeviceIds)
+			{
+				hasVirtualDevice |= DeviceBlacklist.Any(d => device.ToLower().Contains(d.ToLower())) && DeviceWhitelist.All(d => !device.ToLower().Contains(d.ToLower()));
+			}
+
+			return hasVirtualDevice;
+		}
+
+		private bool HasVirtualMacAddress()
+		{
+			var hasVirtualMacAddress = false;
+			var macAddress = systemInfo.MacAddress;
+
+			if (macAddress != null && macAddress.Length > 2)
+			{
+				hasVirtualMacAddress |= macAddress.StartsWith(MANIPULATED);
+				hasVirtualMacAddress |= macAddress.StartsWith(QEMU_MAC_PREFIX);
+				hasVirtualMacAddress |= macAddress.StartsWith(VIRTUALBOX_MAC_PREFIX);
+			}
+
+			return hasVirtualMacAddress;
+		}
+
+		private bool IsVirtualCpu()
+		{
+			var isVirtualCpu = false;
+
+			isVirtualCpu |= systemInfo.CpuName.ToLower().Contains(" kvm ");
+
+			return isVirtualCpu;
+		}
+
+		private bool IsVirtualRegistry()
+		{
+			var isVirtualRegistry = false;
+
+			isVirtualRegistry |= HasLocalVirtualMachineDeviceCache();
+
+			return isVirtualRegistry;
+		}
+
+		private bool IsVirtualSystem(string biosInfo, string manufacturer, string model)
+		{
+			var isVirtualSystem = false;
+
+			biosInfo = biosInfo.ToLower();
+			manufacturer = manufacturer.ToLower();
+			model = model.ToLower();
+
+			isVirtualSystem |= biosInfo.Contains("hyper-v");
+			isVirtualSystem |= biosInfo.Contains("virtualbox");
+			isVirtualSystem |= biosInfo.Contains("vmware");
+			isVirtualSystem |= biosInfo.Contains("ovmf");
+			isVirtualSystem |= biosInfo.Contains("edk ii unknown");
+			isVirtualSystem |= manufacturer.Contains("microsoft corporation") && !model.Contains("surface");
+			isVirtualSystem |= manufacturer.Contains("parallels software");
+			isVirtualSystem |= manufacturer.Contains("qemu");
+			isVirtualSystem |= manufacturer.Contains("vmware");
+			isVirtualSystem |= model.Contains("virtualbox");
+			isVirtualSystem |= model.Contains("Q35 +");
+
+			return isVirtualSystem;
+		}
+
+		private bool HasLocalVirtualMachineDeviceCache()
+		{
+			var deviceName = Environment.GetEnvironmentVariable("COMPUTERNAME");
+			var hasDeviceCache = false;
+			var hasDeviceCacheKeys = registry.TryGetSubKeys(RegistryValue.UserHive.DeviceCache_Key, out var deviceCacheKeys);
+
+			if (deviceName != default && hasDeviceCacheKeys)
+			{
+				foreach (var cacheId in deviceCacheKeys)
+				{
+					var cacheIdKey = $@"{RegistryValue.UserHive.DeviceCache_Key}\{cacheId}";
+					var didReadKeys = true;
+
+					didReadKeys &= registry.TryRead(cacheIdKey, "DeviceName", out var cacheDeviceName);
+
+					if (didReadKeys && deviceName.ToLower() == ((string) cacheDeviceName).ToLower())
+					{
+						didReadKeys &= registry.TryRead(cacheIdKey, "DeviceMake", out var cacheDeviceManufacturer);
+						didReadKeys &= registry.TryRead(cacheIdKey, "DeviceModel", out var cacheDeviceModel);
+
+						if (didReadKeys)
+						{
+							hasDeviceCache |= IsVirtualSystem("", (string) cacheDeviceManufacturer, (string) cacheDeviceModel);
+						}
+					}
+				}
+			}
+
+			return hasDeviceCache;
 		}
 	}
 }