Re: [gdm-list] Help in project

[Brian Cameron <Brian Cameron Sun COM>]

Ravi:

> I am ravi,working as contract engineer in one government sector.
>
> Project requirements:
>
> 1. Login as root without propmting for username & directly into password
> auth dialog.

The old GDM (older than version 2.20) and the upcoming GDM 2.30 release
do support the ability to specify what users show up in the Face Browser
via the Include/Exclude configuration options.  However, I don't think
this will meet your needs since even when the Face Browser is used,
the user can still start a normal PAM conversation which will prompt
for the username.

Note that it is actually PAM which drives the prompts which are
displayed in the GDM login screen.  The GDM program just blindly
displays whatever questions the PAM modules used by the "gdm" PAM
stack specify.

I believe the only way to get this behavior would be to write a custom
PAM module which pre-fills the PAM_USER value with the root username.
This will cause PAM to skip asking for the username and go straight to
asking for the password.

> 2.In password authentication lauching numberpad(onscreen keypad) from 0-10.

You could modify the GDM Init script to launch a program like onscreen.
If using the new GDM, you can set up the GDM configuration to launch
onscreen all the time.

> 3.password max is 8 min is 6 numbers any.

GDM does not allow you to configure what values are accepted as
passwords.  If passwords are only numbers, then if a user enters an
invalid value, the login will fail.

To make the entry field only accept numeric input would likely require
making changes to the source code and building GDM yourself.

I am not familiar with using the onscreen program.  If your environment
requires users to use the onscreen keyboard and does not allow users
to use the physical keyboard, then it might be possible to limit the
entry to numeric input by starting up the onscreen keyboard in a way
that only allows users to enter numeric data.  Though, I am not sure if
the onscreen program allows you to run it this way or not.

> 4.And launch the desktop after password verification.

Both the old and new GDM will simply launch whatever session is
specified at the login screen.  The available sessions are specified
by desktop files in /usr/share/xsessions.  If you want to limit the
available sessions, then you can just make sure that you only
deliver a single desktop file associated with the desktop session
you want users to use.

Note that the old GDM does support a few special session choices
which can be turned off via the ShowGnomeFailsafeSession and
ShowXtermFailsafeSession configuration optins in the [greeter]
section.  If you don't want these to be available, then you can
set the configuration values to false.

> Please help me in:
>
> 1. Can i able to change the greeter program of GDM 2.18.3 to obtain the
> task 1.If possible how?

I believe task #1 will require writing a custom PAM module.  GDM itself
does not provide configuration options to specify the username.

> 2. Can i get the code flow of the GDM to perform the rest of the task.

You can launch the onscreen program in the GDM Init script to accomplish
task #2.  Task #4 also seems to be possible with existing GDM
configuration.

However, I don't think it is possible to limit the entry field to only
accept numeric values, so task #3 may not be easily possible without
changing the GDM code.

> 3. Please give me solution if any other solution is possible for the
> above mentioned task.

Hope this helps.

Brian