Special Kernel Modification

[Lonnie Cumberland <lonnie@outstep.com>]

Hello All,

I am new to this list and am very interested in any help that you might 
be able to give me for a particular Linux project that I am working on.

I am currently using a Pentium III 500Mhz running Mandrake 8.0 Linux and 
Kernel 2.4.3 as a development system.

The basic problem that I am running into is that I am working on an 
Internet related project and thus need to ensure various types of 
document security for the eventual users of this system, if things go well.

I have look into using things like "chroot" to restrict the users for 
this very special server, but that solution is not what we need.

I am building a special xserver that will allow users to login and then 
the xserver will run a single application such as StarOffice. When the 
user exits from the application then the Xserver will log them out.

My problem is that I need to find a way to prevent the user from 
navigating out of their home directories.

I have also looking the possiblility of writing my own filesystem, but I 
am told that this needs to be done at the VFS level.

Is there someone who might be able to give me some information on how I 
could add a few lines to the VFS filesystem so that I might set some 
type of extended attribute to prevent users from navigating out of the 
locations.

Any help would be greatly appreciated,
Lonnie Cumberland