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Change Ribbon and RTD registration to attempt HKCR first, before user…
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… hive
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@govert
govert committed Apr 11, 2015
1 parent 91c0830 commit 6544cda
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Showing 3 changed files with 78 additions and 154 deletions.
176 changes: 74 additions & 102 deletions Source/ExcelDna.Integration/ComRegistration.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Security;
using Microsoft.Win32;
using ExcelDna.Integration;
using ExcelDna.Integration.Extensibility;
Expand Down Expand Up @@ -158,6 +159,68 @@ public int LockServer(bool fLock)

#region Registration Helpers

// We check whether the machine-hive HKCR is writeable (by attempting a write)
// If it is writeable, we register to the machine hive. Otherwise we fall back to the user hive.
// Some care is needed here. See notes at ComServer.RegisterServer().

internal static class RegistrationUtil
{
static RegistryKey _rootKey;

public static RegistryKey ClassesRootKey
{
get
{
if (_rootKey == null)
{
_rootKey = CanWriteMachineHive() ?
Registry.ClassesRoot :
Registry.CurrentUser.CreateSubKey(@"Software\Classes", RegistryKeyPermissionCheck.ReadWriteSubTree);
}
return _rootKey;
}
}

static bool CanWriteMachineHive()
{
// This is not an easy question to answer, due to Registry Virtualization: http://msdn.microsoft.com/en-us/library/aa965884(v=vs.85).aspx
// So if registry virtualization is active, the machine writes will redirect to a special user key.
// I don't know how to detect that case, so we'll just write to the virtualized location.

const string testKeyName = "_ExcelDna.PermissionsTest";
try
{
RegistryKey testKey = Registry.ClassesRoot.CreateSubKey(testKeyName, RegistryKeyPermissionCheck.ReadWriteSubTree);
if (testKey == null)
{
Debug.Print("Unexpected failure in CanWriteMachineHive check");
return false;
}
else
{
Registry.ClassesRoot.DeleteSubKeyTree(testKeyName);

// Looks fine, even though it might well be virtualized to some part of the user hive.
// I'd have preferred to return false in the virtualized case, but don't know how to detect it.
return true;
}
}
catch (UnauthorizedAccessException)
{
return false;
}
catch (SecurityException)
{
return false;
}
catch (Exception e)
{
Debug.Print("Unexpected exception in CanWriteMachineHive check: " + e);
return false;
}
}
}

// Disposable base class
internal abstract class Registration : IDisposable
{
Expand Down Expand Up @@ -209,9 +272,7 @@ protected virtual void Dispose(bool disposing)

internal class ComAddInRegistration : Registration
{
// Some care is needed here. See notes at ComServer.RegisterServer().
// This user-hive registration only always works because we are hosting the ClassFactory explicitly.


readonly string _progId;

public ComAddInRegistration(string progId, string friendlyName, string description)
Expand All @@ -237,55 +298,16 @@ internal class ProgIdRegistration : Registration
public ProgIdRegistration(string progId, CLSID clsId)
{
_progId = progId;
string rootKeyName = RegistrationUtil.ClassesRootKey.Name;

// Register the ProgId for CLSIDFromProgID.
Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\" + _progId + @"\CLSID", null, clsId.ToString("B").ToUpperInvariant(), RegistryValueKind.String);
Registry.SetValue(rootKeyName + @"\" + _progId + @"\CLSID", null, clsId.ToString("B").ToUpperInvariant(), RegistryValueKind.String);
}

protected override void Deregister()
{
// Deregister the ProgId for CLSIDFromProgID.
Registry.CurrentUser.DeleteSubKeyTree(@"Software\Classes\" + _progId);
}
}


// I'm implementating a minimal fix for the CTP loading issue when running under UAC elevation.
// Not sure yet why the RTD servers and ribbons work fine, but not the ActiveX loading.
// So for now I'm just changing the ActiveX control registration to first attempt a machine registration,
// and if that fails to try a user registration.
// CONSIDER: Follow this strategy for all registrations, ro revisit why we have an issue only for this case under UAC elevation.
internal class ProgIdUacRegistration : Registration
{
readonly string _progId;
readonly bool _machineRegistration;

public ProgIdUacRegistration(string progId, CLSID clsId)
{
_progId = progId;

try
{
Registry.SetValue(@"HKEY_CLASSES_ROOT\" + _progId + @"\CLSID", null, clsId.ToString("B").ToUpperInvariant(), RegistryValueKind.String);
_machineRegistration = true;
}
catch
{
Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\" + _progId + @"\CLSID", null, clsId.ToString("B").ToUpperInvariant(), RegistryValueKind.String);
_machineRegistration = false;
}
}

protected override void Deregister()
{
if (_machineRegistration)
{
Registry.ClassesRoot.DeleteSubKeyTree(_progId);
}
else
{
// Deregister the ProgId for CLSIDFromProgID.
Registry.CurrentUser.DeleteSubKeyTree(@"Software\Classes\" + _progId);
}
RegistrationUtil.ClassesRootKey.DeleteSubKeyTree(@"\" + _progId);
}
}

Expand All @@ -296,71 +318,21 @@ public ClsIdRegistration(CLSID clsId, string progId)
{
_clsId = clsId;
string clsIdString = clsId.ToString("B").ToUpperInvariant();
// Register the CLSID
//Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\CLSID\" + clsId.ToString("B"), null, "Excel RTD Helper Class", RegistryValueKind.String);
Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\CLSID\" + clsIdString + @"\InProcServer32", null, DnaLibrary.XllPath, RegistryValueKind.String);
Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\CLSID\" + clsIdString + @"\InProcServer32", "ThreadingModel", "Both", RegistryValueKind.String);
if (!string.IsNullOrEmpty(progId))
{
Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\CLSID\" + clsIdString + @"\ProgID", null, progId, RegistryValueKind.String);
}
}
string rootKeyName = RegistrationUtil.ClassesRootKey.Name;

protected override void Deregister()
{
// Deregister the ProgId for CLSIDFromProgID.
Registry.CurrentUser.DeleteSubKeyTree(@"Software\Classes\CLSID\" + _clsId.ToString("B").ToUpperInvariant());
}
}

// Same story as the ProgIdUacRegistration - for CTP ActiveX control.
internal class ClsIdUacRegistration : Registration
{
readonly Guid _clsId;
readonly bool machineRegistration = false;

public ClsIdUacRegistration(CLSID clsId, string progId)
{
_clsId = clsId;
string clsIdString = clsId.ToString("B").ToUpperInvariant();
// Register the CLSID
// Attempt machine key

try
{
Registry.SetValue(@"HKEY_CLASSES_ROOT\CLSID\" + clsIdString + @"\InProcServer32", null, DnaLibrary.XllPath, RegistryValueKind.String);
Registry.SetValue(@"HKEY_CLASSES_ROOT\CLSID\" + clsIdString + @"\InProcServer32", "ThreadingModel", "Both", RegistryValueKind.String);
if (!string.IsNullOrEmpty(progId))
{
Registry.SetValue(@"HKEY_CLASSES_ROOT\CLSID\" + clsIdString + @"\ProgID", null, progId, RegistryValueKind.String);
}
machineRegistration = true;
}
catch
Registry.SetValue(rootKeyName + @"\CLSID\" + clsIdString + @"\InProcServer32", null, DnaLibrary.XllPath, RegistryValueKind.String);
Registry.SetValue(rootKeyName + @"\CLSID\" + clsIdString + @"\InProcServer32", "ThreadingModel", "Both", RegistryValueKind.String);
if (!string.IsNullOrEmpty(progId))
{
machineRegistration = false;
//Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\CLSID\" + clsId.ToString("B"), null, "Excel RTD Helper Class", RegistryValueKind.String);
Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\CLSID\" + clsIdString + @"\InProcServer32", null, DnaLibrary.XllPath, RegistryValueKind.String);
Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\CLSID\" + clsIdString + @"\InProcServer32", "ThreadingModel", "Both", RegistryValueKind.String);

if (!string.IsNullOrEmpty(progId))
{
Registry.SetValue(@"HKEY_CURRENT_USER\Software\Classes\CLSID\" + clsIdString + @"\ProgID", null, progId, RegistryValueKind.String);
}
Registry.SetValue(rootKeyName + @"\CLSID\" + clsIdString + @"\ProgID", null, progId, RegistryValueKind.String);
}
}

protected override void Deregister()
{
// Deregister the ProgId for CLSIDFromProgID.
if (machineRegistration)
{
Registry.ClassesRoot.DeleteSubKeyTree(@"CLSID\" + _clsId.ToString("B").ToUpperInvariant());
}
else
{
Registry.CurrentUser.DeleteSubKeyTree(@"Software\Classes\CLSID\" + _clsId.ToString("B").ToUpperInvariant());
}
RegistrationUtil.ClassesRootKey.DeleteSubKeyTree(@"\CLSID\" + _clsId.ToString("B").ToUpperInvariant());
}
}

Expand Down
48 changes: 2 additions & 46 deletions Source/ExcelDna.Integration/ComServer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,6 @@
using System.Diagnostics;
using System.Globalization;
using System.Runtime.InteropServices;
using System.Security;
using Microsoft.Win32;
using ExcelDna.Integration;
using ExcelDna.ComInterop.ComRegistration;
Expand Down Expand Up @@ -171,7 +170,7 @@ public void RegisterServer()
// http://blogs.msdn.com/b/cjacks/archive/2008/06/06/per-user-com-registrations-and-elevated-processes-with-uac-on-windows-vista-sp1.aspx
// http://blogs.msdn.com/b/cjacks/archive/2008/07/22/per-user-com-registrations-and-elevated-processes-with-uac-on-windows-vista-sp1-part-2-ole-automation.aspx

string rootKeyName = CanWriteMachineHive() ? "HKEY_CLASSES_ROOT" : @"HKEY_CURRENT_USER\Software\Classes";
string rootKeyName = RegistrationUtil.ClassesRootKey.Name;

// Register the ProgId for CLSIDFromProgID.
string clsIdString = ClsId.ToString("B").ToUpperInvariant();
Expand All @@ -194,8 +193,7 @@ public void RegisterServer()
// Can throw UnauthorizedAccessException if nothing is writeable
public void UnregisterServer()
{
RegistryKey rootKey = CanWriteMachineHive() ? Registry.ClassesRoot :
Registry.CurrentUser.CreateSubKey(@"Software\Classes", RegistryKeyPermissionCheck.ReadWriteSubTree);
RegistryKey rootKey = RegistrationUtil.ClassesRootKey;

if (!string.IsNullOrEmpty(TypeLibPath))
{
Expand Down Expand Up @@ -306,47 +304,5 @@ private void UnregisterTypeLibrary(RegistryKey rootKey)
}
}

private static bool CanWriteMachineHive()
{
// This is not an easy question to answer, due to Registry Virtualization: http://msdn.microsoft.com/en-us/library/aa965884(v=vs.85).aspx
// So if registry virtualization is active, the machine writes will redirect to a special user key.
// I don't know how to detect that case, so we'll just write to the virtualized location.

if (_canWriteMachineHive.HasValue)
return _canWriteMachineHive.Value;

const string testKeyName = "_ExcelDna.PermissionsTest";
try
{
RegistryKey testKey = Registry.ClassesRoot.CreateSubKey(testKeyName, RegistryKeyPermissionCheck.ReadWriteSubTree);
if (testKey == null)
{
Debug.Print("Unexpected failure in CanWriteMachineHive check");
_canWriteMachineHive = false;
}
else
{
Registry.ClassesRoot.DeleteSubKeyTree(testKeyName);

// Looks fine, even though it might well be virtualized to some part of the user hive.
// I'd have preferred to return false in the virtualized case, but don't know how to detect it.
_canWriteMachineHive = true;
}
}
catch (UnauthorizedAccessException)
{
_canWriteMachineHive = false;
}
catch (SecurityException)
{
_canWriteMachineHive = false;
}
catch (Exception e)
{
Debug.Print("Unexpected exception in CanWriteMachineHive check: " + e);
_canWriteMachineHive = false;
}
return _canWriteMachineHive.Value;
}
}
}
8 changes: 2 additions & 6 deletions Source/ExcelDna.Integration/ExcelCustomTaskPane.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -63,16 +63,12 @@ public static CustomTaskPane CreateCustomTaskPane(Type userControlType, string t
string progId = "CtpSrv." + clsId.ToString("N");

// Instantiate and then register UserControl
// For some reason, there is a problem loading the user control when running under an elevated UAC token.
// So we use the form of the registration which tries to first register for the machine,
// then fall back to the user hive if that fails.

try
{
object userControl = Activator.CreateInstance(userControlType);
using (new SingletonClassFactoryRegistration(userControl, clsId))
using (new ProgIdUacRegistration(progId, clsId))
using (new ClsIdUacRegistration(clsId, progId))
using (new ProgIdRegistration(progId, clsId))
using (new ClsIdRegistration(clsId, progId))
{
return CreateCustomTaskPane(progId, title, parent);
}
Expand Down

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