Visual Basic.net - AdjustTokenPrivileges successful but ExitWindowsEx fails with LastDllError is 5

Question

I am developing an application which able shutdown or restart windows. As what I've googled, There are four steps:

1. call OpenProcessToken(...)
2. check LookupPrivilegeValue(...)
3. call AdjustTokenPrivileges(...)
4. call ExitWindowsEx(1, 0).

What happened is that until step 3, AdjustTokenPrivileges, all are fine. AdjustTokenPrivileges has set SE_SHUTDOWN_PRIVILEGE, then returns true and err.LastDllError is ERROR_SUCCESS (&h0). But when I call ExitWindowsEx to shutdown windows, it returns 0 and err.LastDllError is 5. Using errlook command in Visual Studio command prompt, the number 5 means "Access Denied".

I usually work with standard user account (not admin). Later I tried to change requested execution level in app.manifest like this:

<requestedExecutionLevel level="asInvoker" uiAccess="false" />

and then re-run the application as administrator. But no use, I'm still getting LastDllError = 5, access denied.

I am using Windows 7 64-bit with Visual Studio 2010 and .NET framework 4 installed. But for this application I target .NET 3.5 as most my friends have not ready yet for .NET 4. Also the result is the same regardless I compile it to x64 or x86.

Here is my problematic code:

Dim tp As Token_Privileges

Dim processhandle As IntPtr = GetCurrentProcess()

Dim tokenhandle As IntPtr = IntPtr.Zero

'Dim retlength As Integer

OpenProcessToken(processhandle, TOKEN_ADJUST_PRIVILEGES Or TOKEN_QUERY, tokenhandle)

tp.Count = 1

tp.Luid = 0

tp.Attr = SE_PRIVILEGE_ENABLED

'Check whether privilege exists or not

If Not LookupPrivilegeValue(vbNullString, SE_SHUTDOWN_NAME, tp.Luid) Then

    MessageBox.Show("LookupPrivilegeValue returns false")

End If

Err.Clear()

'set shutdown privilege

If Not AdjustTokenPrivileges(tokenhandle, False, tp, 0, IntPtr.Zero, IntPtr.Zero) Then

    MessageBox.Show(Err.LastDllError) 'this message box never executed,

    'which mean AdjustToken successful

End If

If Not ExitWindowsEx(1, 0) Then

    MessageBox.Show(Err.LastDllError) 'this always shows "5"

End If

I have read many MSDN blogs and googling here and there, wasting a day, but still getting access denied.

Another thing what I am wondering is why his code in C# works but mine does not? (He even didn't bother to mess with privileges and tokens..)

Oh, I couldn't find a suitable forum title for programming or development in MS answer's new thread page. Moderators, feel free to move this thread into appropriate forum.

Thanks.

Answer 1

Hi yusufat,

Your Windows 7 question is more complex than what is typically answered in the Microsoft Answers Forums. It is better suited for the Visual Basic audience on Visual Basic Forums. Please post your question in the Visual Basic Forums.

Link: http://social.msdn.microsoft.com/Forums/en-US/category/visualbasic/

For the entire list of Microsoft Forums, see Microsoft Forums

Hope this helps.

Regards,

Syed - Microsoft Support.

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