fix(hid): Wrap event Windows HID handler logic inside of try/catch-block

Author: DennisDyallo

Yubico.Core/src/Yubico/Core/Devices/Hid/WindowsHidDeviceListener.cs

@@ -113,40 +113,52 @@ private static int OnEventReceived(
         {
             var thisPtr = GCHandle.FromIntPtr(context);
             var thisObj = thisPtr.Target as WindowsHidDeviceListener;
-            thisObj?._log.LogInformation("ConfigMgr callback received.");
 
-            CM_NOTIFY_EVENT_DATA eventData = Marshal.PtrToStructure<CM_NOTIFY_EVENT_DATA>(eventDataPtr);
-            Debug.Assert(eventData.ClassGuid == CmInterfaceGuid.Hid);
-            Debug.Assert(eventData.FilterType == CM_NOTIFY_FILTER_TYPE.DEVINTERFACE);
+            try
+            {
 
-            int stringOffset = 24; // Magic number from C land
-            int stringSize = eventDataSize - stringOffset;
-            byte[] buffer = new byte[eventDataSize];
+                CM_NOTIFY_EVENT_DATA eventData = Marshal.PtrToStructure<CM_NOTIFY_EVENT_DATA>(eventDataPtr);
+                Debug.Assert(eventData.ClassGuid == CmInterfaceGuid.Hid);
+                Debug.Assert(eventData.FilterType == CM_NOTIFY_FILTER_TYPE.DEVINTERFACE);
 
-            Marshal.Copy(eventDataPtr + stringOffset, buffer, 0, stringSize);
+                int stringOffset = 24; // Magic number from C land
+                int stringSize = eventDataSize - stringOffset;
+                byte[] buffer = new byte[eventDataSize];
 
-            switch (action)
-            {
-                case CM_NOTIFY_ACTION.DEVICEINTERFACEARRIVAL:
-                    {
-                        string instancePath = System.Text.Encoding.Unicode.GetString(buffer);
-                        var cmDevice = CmDevice.FromDevicePath(instancePath);
-                        if (cmDevice == null)
+                Marshal.Copy(eventDataPtr + stringOffset, buffer, 0, stringSize);
+
+                switch (action)
+                {
+                    case CM_NOTIFY_ACTION.DEVICEINTERFACEARRIVAL:
                         {
-                            thisObj?._log.LogWarning("Failed to create CmDevice from instance path {InstancePath}.", instancePath);
-                            return 0; // We can't do anything without a CmDevice. Exit gracefully.
+                            string instancePath = System.Text.Encoding.Unicode.GetString(buffer);
+                            var cmDevice = CmDevice.FromDevicePath(instancePath);
+                            if (cmDevice == null)
+                            {
+                                thisObj?._log.LogWarning(
+                                    "Failed to create CmDevice from instance path {InstancePath}.", instancePath);
+
+                                return 0; // We can't do anything without a CmDevice. Exit gracefully.
+                            }
+
+                            var device = new WindowsHidDevice(cmDevice);
+                            thisObj?.OnArrived(device);
+                            break;
                         }
-                        
-                        var device = new WindowsHidDevice(cmDevice);
-                        thisObj?.OnArrived(device);
+                    case CM_NOTIFY_ACTION.DEVICEINTERFACEREMOVAL:
+                        thisObj?.OnRemoved(NullDevice.Instance);
                         break;
-                    }
-                case CM_NOTIFY_ACTION.DEVICEINTERFACEREMOVAL:
-                    thisObj?.OnRemoved(NullDevice.Instance);
-                    break;
-            }
+                }
 
-            return 0;
+                return 0;
+            }
+            catch (Exception ex)
+            {
+                // We must not let exceptions escape from this callback. There's nowhere for them to go, and
+                // it will likely crash the process.
+                thisObj?._log.LogDebug($"Exception in OnEventReceived: {ex}");
+                return 0;
+            }
         }
     }
 }