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From: dc2000 on 15 Nov 2006 00:08
Thanks. But how will I get HANDLE hWlx to call that API? Please note that I'm
not calling this API from GINA replacement DLL.


"Skywing [MVP]" wrote:

> WlxDialogBox* from a GINA DLL. Note that GINA DLLs are obsolete and
> unusable in Windows Vista and future OS releases.
>
> --
> Ken Johnson (Skywing)
> Windows SDK MVP
> http://www.nynaeve.net
>
> "dc2000" <dc2000(a)discussions.microsoft.com> wrote in message
> news:B5021860-82E2-4EB8-BD9B-48B2C7AA6B1F(a)microsoft.com...
> > Hey, it just dawned on me. Is there any way to display my own dialog
> > window
> > during Winlogon?
> >
> >
> > "anton bassov" wrote:
> >
> >> Hi mate
> >>
> >> > Everything works fine when user's desktop is shown. If I go into
> >> > Winlogon by
> >> > clicking Start -> Log Off -> Switch User (see picture here:
> >> > http://www.codeguru.com/forum/attachment.php?attachmentid=17852&stc=1),
> >> > the
> >> > message is displayed but FindWindow() returns NULL. I tried
> >> > EnumWindows() and
> >> > it failed as well.
> >>
> >> When you specify MB_SERVICE_NOTIFICATION flag, message box is displayed
> >> as ZwRaiseHardError() call, so that it is owned by csrss.exe, rather
> >> than by caller, and,as a result, it gets displayed on currently active
> >> desktop. However, it does not mean that the caller has an access to
> >> this destop. In general, under Windows, desktop is a security boundary.
> >> Therefore, FindWindow() and EnumWindows() are able to find and
> >> enumerate
> >> only those windows that belong to the desktop the caller is associated
> >> with
> >>
> >>
> >>
> >> > I heard that one solution would be to use CBT_HOOK but for that I will
> >> > need
> >> > a separate DLL module (for global hook),
> >>
> >> It is not going to work either - Windows hooks are of desktop-level
> >> scope
> >>
> >>
> >> > Does anyone know how to get a handle to this message box during
> >> > Winlogon?
> >>
> >> You cannot do it in your application's context - no one, apart from
> >> Winlogon.exe, has an access to "Winlogon" desktop. If you are Admin,
> >> you may assign yourself privileges of LocalSystem account, so that you
> >> are able to open a handle to Winlogon.exe and inject a DLL into it
> >>
> >> Anton Bassov
> >>
> >> dc2000 wrote:
> >> > Hi everyone:
> >> >
> >> >
> >> > I have a tricky situation. My app displays a message box using
> >> > MB_SERVICE_NOTIFICATION flag like this:
> >> >
> >> > ::MessageBox(NULL, message, title, MB_OK | MB_ICONINFORMATION |
> >> > MB_SERVICE_NOTIFICATION);
> >> >
> >> > I'm using MB_SERVICE_NOTIFICATION since I need this message to be
> >> > displayed
> >> > over screen-saver, or Winlogon as well.
> >> >
> >> >
> >> > When the window is shown on the screen I use WM_TIMER message and
> >> > FindWindow() to get the handle of the Message Box and later update text
> >> > displayed in it.
> >> >
> >> > HWND hMsgBxWnd = ::FindWindow("#32770", title);
> >> >
> >> > //Get handle to the static window in the Message Box
> >> > if(::GetDlgItem(hMsgBxWnd, 0xffff))
> >> > {
> >> > //Got it, now can update it
> >> > ::SetDlgItemText(hMsgBxWnd, 0xffff, message_str);
> >> > }
> >> >
> >> > Everything works fine when user's desktop is shown. If I go into
> >> > Winlogon by
> >> > clicking Start -> Log Off -> Switch User (see picture here:
> >> > http://www.codeguru.com/forum/attachment.php?attachmentid=17852&stc=1),
> >> > the
> >> > message is displayed but FindWindow() returns NULL. I tried
> >> > EnumWindows() and
> >> > it failed as well.
> >> >
> >> > I heard that one solution would be to use CBT_HOOK but for that I will
> >> > need
> >> > a separate DLL module (for global hook), which I'd really like to
> >> > avoid.
> >> >
> >> > Does anyone know how to get a handle to this message box during
> >> > Winlogon?
> >> >
> >> >
> >> > FYI. The currently active Terminal Session is still the same as when
> >> > the
> >> > message is shown during Winlogon.
> >>
> >>
>
>
>
From: Grzegorz Wróbel on 15 Nov 2006 03:17
dc2000 wrote:
> Thanks. But how will I get HANDLE hWlx to call that API? Please note that I'm
> not calling this API from GINA replacement DLL.

You won't. These functions are meant to be used only from within GINA.
Unless you're going for some really ugly hack.

--
Grzegorz Wróbel
http://www.4neurons.com/
677265676F727940346E6575726F6E732E636F6D
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