Winget COM API - Allow lower trust registration

src/UniGetUI.PackageEngine.Managers.WinGet/WinGetHelpers/NativeWinGetHelper.cs

@@ -27,10 +27,10 @@ public NativeWinGetHelper()
 
         if (CoreTools.IsAdministrator())
         {
-            Logger.Info("Running elevated, WinGet class registration is likely to fail");
+            Logger.Info("Running elevated, WinGet class registration is likely to fail unless using lower trust class registration is allowed in settings");
         }
 
-        Factory = new WindowsPackageManagerStandardFactory();
+        Factory = new WindowsPackageManagerStandardFactory(allowLowerTrustRegistration:Settings.Get("AllowLowerTrustRegistration"));
         WinGetManager = Factory.CreatePackageManager();
     }
 

src/UniGetUI/Pages/SettingsPage.xaml.cs

@@ -113,6 +113,14 @@ public SettingsInterface()
                 CoreTools.LaunchBatchFile(Path.Join(CoreData.UniGetUIExecutableDirectory, "Assets", "Utilities", "reset_winget_sources.cmd"), CoreTools.Translate("Resetting Winget sources - WingetUI"), RunAsAdmin: true);
             };
 
+            CheckboxCard Winget_AllowLowerTrustRegistration = new()
+            {
+                Text = CoreTools.Translate("Allow using class registered with lower trust"),
+                SettingName = "AllowLowerTrustRegistration",
+            };
+            Winget_AllowLowerTrustRegistration.StateChanged += (s, e) => PackageManagerExpanders[PEInterface.WinGet].ShowRestartRequiredBanner();
+            Winget_AllowLowerTrustRegistration.IsEnabled = !Settings.Get("ForceLegacyBundledWinGet");
+
             CheckboxCard Winget_DisableCOM = new()
             {
                 Text = CoreTools.Translate("Use the WinGet PowerShell Module instead of the WinGet COM API"),
@@ -133,6 +141,7 @@ public SettingsInterface()
             };
 
             ExtraSettingsCards[PEInterface.WinGet].Add(Winget_UseBundled);
+            ExtraSettingsCards[PEInterface.WinGet].Add(Winget_AllowLowerTrustRegistration);
             ExtraSettingsCards[PEInterface.WinGet].Add(Winget_DisableCOM);
             ExtraSettingsCards[PEInterface.WinGet].Add(Winget_ResetSources);
 

src/WindowsPackageManager.Interop/WindowsPackageManager/WindowsPackageManagerFactory.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation.
+// Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
 using Microsoft.Management.Deployment;
@@ -13,10 +13,12 @@ namespace WindowsPackageManager.Interop;
 public abstract class WindowsPackageManagerFactory
 {
     private readonly ClsidContext _clsidContext;
+    protected readonly bool _allowLowerTrustRegistration;
 
-    public WindowsPackageManagerFactory(ClsidContext clsidContext)
+    public WindowsPackageManagerFactory(ClsidContext clsidContext, bool allowLowerTrustRegistration = false)
     {
         _clsidContext = clsidContext;
+        _allowLowerTrustRegistration = allowLowerTrustRegistration;
     }
 
     /// <summary>

src/WindowsPackageManager.Interop/WindowsPackageManager/WindowsPackageManagerStandardFactory.cs

@@ -10,8 +10,8 @@ namespace WindowsPackageManager.Interop;
 
 public class WindowsPackageManagerStandardFactory : WindowsPackageManagerFactory
 {
-    public WindowsPackageManagerStandardFactory(ClsidContext clsidContext = ClsidContext.Prod)
-        : base(clsidContext)
+    public WindowsPackageManagerStandardFactory(ClsidContext clsidContext = ClsidContext.Prod, bool allowLowerTrustRegistration = false)
+        : base(clsidContext, allowLowerTrustRegistration)
     {
     }
 
@@ -20,12 +20,19 @@ protected override T CreateInstance<T>(Guid clsid, Guid iid)
         nint pUnknown = IntPtr.Zero;
         try
         {
-            Windows.Win32.Foundation.HRESULT hr = PInvoke.CoCreateInstance(clsid, null, CLSCTX.CLSCTX_LOCAL_SERVER, iid, out object result);
+            CLSCTX clsctx = CLSCTX.CLSCTX_LOCAL_SERVER;
+            if(_allowLowerTrustRegistration)
+            {
+                clsctx |= CLSCTX.CLSCTX_ALLOW_LOWER_TRUST_REGISTRATION;
+            }
+
+            Windows.Win32.Foundation.HRESULT hr = PInvoke.CoCreateInstance(clsid, null, clsctx, iid, out object result);
 
             //                     !! WARNING !!
             // An exception may be thrown on the line below if UniGetUI
-            // runs as administrator or when WinGet is not installed on the
-            // system. It can be safely ignored if any of the conditions
+            // runs as administrator and AllowLowerTrustRegistration settings is not checked
+            // or when WinGet is not installed on the system.
+            // It can be safely ignored if any of the conditions
             // above are met.
             Marshal.ThrowExceptionForHR(hr);