Mouse Without Borders: create received files in the logged-on user's context

src/modules/MouseWithoutBorders/App/Core/Clipboard.cs

@@ -574,32 +574,73 @@ internal static void ReceiveAndProcessClipboardData(string remoteMachine, Socket
             }
             else
             {
+                // Create received files in the same context that the destination folder is created
+                // in. For per-user storage (the user's Desktop) that means as the logged-on user, so
+                // the file ends up owned by that user and inherits the folder's permissions. On the
+                // logon/screen-saver desktop the storage lives under Program Files where there is no
+                // interactive user to impersonate, so create the file directly.
+                void CreateDestinationFile(string path)
+                {
+                    if (Common.RunOnLogonDesktop || Common.RunOnScrSaverDesktop)
+                    {
+                        m = new FileStream(path, FileMode.Create);
+                    }
+                    else
+                    {
+                        bool success = Launch.ImpersonateLoggedOnUserAndDoSomething(() =>
+                        {
+                            m = new FileStream(path, FileMode.Create);
+                        });
+
+                        if (!success || m == null)
+                        {
+                            Logger.Log("Impersonation failed for file creation, falling back to direct creation.");
+                            m = new FileStream(path, FileMode.Create);
+                        }
+                    }
+                }
+
                 if (postAct.Equals("desktop", StringComparison.OrdinalIgnoreCase))
                 {
-                    _ = Launch.ImpersonateLoggedOnUserAndDoSomething(() =>
+                    // Create the folder and open the file in a single impersonated scope so both
+                    // are owned by the logged-on user. This branch always targets the user's Desktop.
+                    bool success = Launch.ImpersonateLoggedOnUserAndDoSomething(() =>
                     {
                         savingFolder = Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\MouseWithoutBorders\\";
 
                         if (!Directory.Exists(savingFolder))
                         {
                             _ = Directory.CreateDirectory(savingFolder);
                         }
+
+                        tempFile = savingFolder + Path.GetFileName(fileName);
+                        m = new FileStream(tempFile, FileMode.Create);
                     });
 
-                    tempFile = savingFolder + Path.GetFileName(fileName);
-                    m = new FileStream(tempFile, FileMode.Create);
+                    if (!success || m == null)
+                    {
+                        Logger.Log("Impersonation failed for desktop file creation, falling back to direct creation.");
+                        savingFolder = Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\MouseWithoutBorders\\";
+                        if (!Directory.Exists(savingFolder))
+                        {
+                            _ = Directory.CreateDirectory(savingFolder);
+                        }
+
+                        tempFile = savingFolder + Path.GetFileName(fileName);
+                        m = new FileStream(tempFile, FileMode.Create);
+                    }
                 }
                 else if (postAct.Contains("mspaint"))
                 {
                     tempFile = Common.GetMyStorageDir() + @"ScreenCapture-" +
                         remoteMachine + ".png";
-                    m = new FileStream(tempFile, FileMode.Create);
+                    CreateDestinationFile(tempFile);
                 }
                 else
                 {
                     tempFile = Common.GetMyStorageDir();
                     tempFile += Path.GetFileName(fileName);
-                    m = new FileStream(tempFile, FileMode.Create);
+                    CreateDestinationFile(tempFile);
                 }
 
                 Logger.Log("==> " + tempFile);