Re: [malware-list] scanner interface proposal was: [TALPA] Intro to a linux interface for on access scanning

From: Pavel Machek <pavel@suse.cz>
To: tvrtko.ursulin@sophos.com
Cc: Theodore Tso <tytso@mit.edu>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Arjan van de Ven <arjan@infradead.org>,
	Adrian Bunk <bunk@kernel.org>,
	capibara@xs4all.nl, Casey Schaufler <casey@schaufler-ca.com>,
	davecb@sun.com, david@lang.hm,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-security-module@vger.kernel.org,
	malware-list@lists.printk.net,
	malware-list-bounces@dmesg.printk.net,
	Mihai Don??u <mdontu@bitdefender.com>,
	Peter Dolding <oiaohm@gmail.com>,
	rmeijer@xs4all.nl
Subject: Re: [malware-list] scanner interface proposal was: [TALPA] Intro to a linux interface for on access scanning
Date: Tue, 19 Aug 2008 00:40:58 +0200	[thread overview]
Message-ID: <20080818224058.GA2311@elf.ucw.cz> (raw)
In-Reply-To: <20080818153212.6A6FD33687F@pmx1.sophos.com>

Hi!

> > On Mon, Aug 18, 2008 at 02:15:24PM +0100, tvrtko.ursulin@sophos.com 
> wrote:
> > > Then there is still a question of who allows some binary to declare 
> itself 
> > > exempt. If that decision was a mistake, or it gets compromised 
> security 
> > > will be off. A very powerful mechanism which must not be easily 
> > > accessible.  With a good cache your worries go away even without a 
> scheme 
> > > like this.
> > 
> > I have one word for you --- bittorrent.  If you are downloading a very
> > large torrent (say approximately a gigabyte), and it contains many
> > pdf's that are say a few megabytes a piece, and things are coming in
> > tribbles, having either a indexing scanner or an AV scanner wake up
> > and rescan the file from scratch each time a tiny piece of the pdf
> > comes in is going to eat your machine alive....
> 
> Huh? I was never advocating re-scan after each modification and I even 
> explicitly said it does not make sense for AV not only for performance but 
> because it will be useless most of the time. I thought sending out 
> modified notification on close makes sense because it is a natural point, 
> unless someone is trying to subvert which is out of scope. Other
> have 

Why do you think non-malicious applications won't write after close /
keep file open forever?
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html