to hide file

[A.Fadyushin at it-centre.ru]

> -----Original Message-----
> From: redhat-list-bounces at redhat.com [mailto:redhat-list-
> bounces at redhat.com] On Behalf Of Dave Ihnat
> Sent: Monday, August 29, 2005 4:08 PM
> To: General Red Hat Linux discussion list
> Subject: Re: to hide file
> 
> On Mon, Aug 29, 2005 at 11:52:08AM +0400, A.Fadyushin at it-centre.ru
wrote:
> > There is no special 'hide' property for files or directories in
Linux
> > filesystem. Therefore, the filesystem will always report to
application
> > every file in the directory.
> 
> Oh, there are tricks that have been used for decades in Unix that will
> still work in Linux.  For instance, create a directory as a
mountpoint;
> put some files and directories in it, then mount an filesystem over
it.
> I believe that still works in Linux.
> 
> Another trick used to be to remove the actual ".." directory entry
with
> an entry that really points off to another directory; this was called
a
> 'hyperspace link'.  I don't know if that still works, but it's an
example
> of the kind of things crackers _can_ do to hide files and directories.
> --
> 	Dave Ihnat
> 	ignatz at dminet.com
> 
> --

The trick with mountpoint works in Linux. But that trick does not give
you the exact equivalent of hidden files as they usually exist in DOS
and Windows. In those systems you always can access hidden file if you
know its name, but you can not see it - the system will not report the
presence of the file in the filesystem. In contrast, when you hide files
behind a mountpoint, the files become inaccessible for future open
calls, only files which were open before mount will be accessible for
processes which opened them. You will not see the hidden file(s) (as in
DOS/Windows) but you will not be able to open it even if you know its
name (unlike DOS/Windows).

As far as I know there is no way in Linux filesystem to receive the same
behavior for hidden files as in DOS/Windows (the usual '.' in the
beginning of file name is not a filesystem feature, it is a feature of
application which support it).

Alexey Fadyushin.
Brainbench MVP for Linux.
http://www.brainbench.com