Re: setting initial prompt of gdmlogin using PAM conversation functio n

[George <jirka 5z com>]

On Fri, Feb 14, 2003 at 06:48:46PM -0800, Naomaru Itoi wrote:
> Hi, 
> 
> Thank you for your great job as usual. 
> 
> We are writing a smartcard PAM module, and are trying to set a prompt in GDM
> Greeter (gdmlogin).  We want to prompt something like "Please enter username
> or insert smartcard" at the begining of the login process.  We are testing
> this with gdmlogin.  
> 
> We can set a prompt using a conversation function all right.  This is good.
> (Thanks!)
> 
> However, gdmlogin always displays a prompt "Username" before calling
> pam_sm_authenticate().  It is only after a user enters a username and hits
> Enter Key that pam_sm_authenticate() is called.  So our PAM module doesn't
> have a chance to override the initial message.  
> 
> Is there any way to work around it and display a different message as the
> initial message?

Not currently.  This requires some rework of how gdm works.  It would not be
too hard actually and Sun seems to be interested in doing this too.  The
basic idea is to change gdm to not assume that we get a username before pam.
I'm busy working on my thesis (and related stuff) currently so I don't really
have time to work on this right now.  I'd really like this to be done for
gnome 2.4 however as it would bring gdm into full pam compliance.

The biggest problem is passwordless guest login that is currently done in
gdm.  I suppose we can somewhat scrap this feature and say that it should be
done in pam and not in gdm.

> I guess we can replace the greeter by changing gdm.conf.  But we would like
> to limit our code to the PAM module, if possible.  

Of course, however currently gdm doesn't allow this.  In fact even replacing
the greeter won't help you here except only for changing the initial prompt.
I suppose you want the username to be read from the smartcard, but currently
the username reading is going outside of pam.

George

-- 
George <jirka 5z com>
   Let's not bicker and argue about who killed who.
                       -- Monty Python