[1486] in bugtraq
Re: randomizing filehandles: why not use fsirand?
daemon@ATHENA.MIT.EDU (Yossi Gottlieb)
Sat Apr 15 09:50:44 1995
From: Yossi Gottlieb <yogo@math.tau.ac.il>
To: bugtraq@fc.net
Date: Fri, 14 Apr 1995 15:03:51 +0300 (GMT+0300)
In-Reply-To: <199504081300.AA06588@uni4nn.iaf.nl> from "Peter Bouthoorn" at Apr 8, 95 02:00:03 pm
> I've wondered why noone (to my knowledge) has suggested to write
> a tool similar to fsirand. Fsirand randomizes all inode numbers
> on a system, which makes guessing file handles a little harder.
> Of course the randomization used in such a tool should be
> "really random", so that we don't end up with the same problem
> as SunOS: the random element used in fsirand wasn't random enough.
> Comments anyone?
The random part is NOT the inode number, but rather a 32bit 'generation'
number, which is a part of the filehandle (the only part you can't
compute).
It seems like the ext2 inode support this (i_version field), but I am not
sure how it is treated by the ext2 code (it DOES handle it, says grep). There
should also be some kind of interface for the NFS server (running as a user
process for now) to ask for i_version....
yossi.
