Re: "Write once only but read many" filesystem

["Jörn Engel" <joern@logfs.org>]

On Sat, 22 March 2008 23:55:53 +0800, Peter Teoh wrote:
> 
> >   Or do you want individual files/directories to be immutable - chattr?
> 
> chattr is not good enough, as root can still modify it.   So if
> current feature is not there, then some small development may be
> needed.
> 
> >  And in either case, what problem do you want to solve with a read-only filesystem?
> 
> Simple:   i want to record down everything that a user does, or a
> database does, or any applications running - just record down its
> state permanently securely into the filesystem, knowing that for sure,
> there is not way to modify the data, short of recreating the
> filesystem again.    Sound logical?   Or is there any loophole in this
> concept?

The loophole is called root.  In a normal setup, root can do anything,
including writing directly to the device your filesystem resides in,
writing to kernel memory, etc.

It may be rather inconvenient to change a filesystem by writing to the
block device, but far from impossible.  If you want to make such changes
impossible, you are facing an uphill battle that I personally don't care
about.  And if inconvenience is good enough, wouldn't chattr be
sufficiently inconvenient?

Jörn

-- 
Victory in war is not repetitious.
-- Sun Tzu
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