From: david@lang.hm
To: David Collier-Brown <davecb@sun.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
tvrtko.ursulin@sophos.com, Theodore Tso <tytso@mit.edu>,
Arjan van de Ven <arjan@infradead.org>,
Adrian Bunk <bunk@kernel.org>,
capibara@xs4all.nl, Casey Schaufler <casey@schaufler-ca.com>,
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>, Pavel Machek <pavel@suse.cz>,
rmeijer@xs4all.nl
Subject: Re: [malware-list] scanner interface proposal was: [TALPA] Intro to a linux interface for on access scanning
Date: Mon, 18 Aug 2008 11:13:26 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.1.10.0808181110040.15109@asgard.lang.hm> (raw)
In-Reply-To: <48A97C42.4040103@sun.com>
On Mon, 18 Aug 2008, David Collier-Brown wrote:
> tvrtko.ursulin wrote:
>>> 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
>>> suggested time delay and lumping up.
>
> Alan Cox wrote:
>> You need a bit more than close I imagine, otherwise I can simply keep the
>> file open forever. There are lots of cases where that would be natural
>> behaviour - eg if I was to attack some kind of web forum and insert a
>> windows worm into the forum which was database backed the file would
>> probably never be closed. That seems to be one of the more common attack
>> vectors nowdays.
>
> I suspect we're saying "on close" when what's really meant is
> "opened for write". In the latter case, the notification would tell
> the user-space program to watch for changes, possibly by something as
> simple as doing a stat now and another when it gets around to deciding if it
> should scan the file. I see lots of room for
> user-space alternatives for change detection, depending on how much
> state it keeps. Rsync-like, perhaps?
trying to have every scanner program monitor every file that any program
opens for write by doing periodic stat commands on it sounds like a very
inefficiant process (and unless they then get notified on close as well,
how do they know when to stop monitoring?)
getting a notification on the transition from scanned -> dirty is much
less of a load (yes, it does leave open the possiblilty of a file getting
scanned multiple times as it keeps getting dirtied, but that's a policy
question of how aggressive the scanner is set to be in scanning files)
David Lang
next prev parent reply other threads:[~2008-08-18 18:13 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.DEB.1.10.0808180444390.12859@asgard.lang.hm>
[not found] ` <20080818131628.1C2A22FE82F@pmx1.sophos.com>
2008-08-18 14:25 ` [malware-list] scanner interface proposal was: [TALPA] Intro to a linux interface for on access scanning Theodore Tso
2008-08-18 15:31 ` tvrtko.ursulin
2008-08-18 15:31 ` Alan Cox
2008-08-18 13:42 ` David Collier-Brown
2008-08-18 17:53 ` Alan Cox
2008-08-18 18:13 ` david [this message]
2008-08-18 15:58 ` tvrtko.ursulin
2008-08-18 17:13 ` david
2008-08-18 16:15 ` Eric Paris
2008-08-18 16:15 ` Alan Cox
2008-08-18 16:54 ` douglas.leeder
2008-08-18 16:40 ` Alan Cox
2008-08-18 17:28 ` Eric Paris
2008-08-18 17:25 ` Alan Cox
2008-08-18 17:54 ` Eric Paris
2008-08-18 18:30 ` Eric Paris
2008-08-18 18:51 ` Alan Cox
2008-08-18 18:35 ` Jan Harkes
2008-08-18 18:46 ` Eric Paris
2008-08-18 19:04 ` david
2008-08-20 2:44 ` [malware-list] scanner interface proposal was: [TALPA] Intro linux interface for for " david
2008-08-20 15:15 ` Eric Paris
2008-08-20 17:33 ` david
2008-08-20 19:26 ` Eric Paris
2008-08-21 0:42 ` david
2008-08-20 17:50 ` david
2008-08-21 14:35 ` [malware-list] scanner interface proposal was: [TALPA] Intro linux interface " douglas.leeder
2008-08-21 21:19 ` david
2008-08-22 15:09 ` [malware-list] scanner interface proposal was: [TALPA] Intro linux interface for " Pavel Machek
2008-08-23 7:28 ` david
2008-08-18 19:32 ` [malware-list] scanner interface proposal was: [TALPA] Intro to a linux interface for on " Jan Harkes
2008-08-18 17:38 ` david
2008-08-18 17:29 ` david
2008-08-18 17:39 ` Eric Paris
2008-08-18 18:09 ` david
2008-08-18 18:34 ` Eric Paris
2008-08-18 17:07 ` david
2008-08-19 8:40 ` tvrtko.ursulin
2008-08-18 22:40 ` Pavel Machek
2008-08-18 23:07 ` Eric Paris
2008-08-19 1:15 ` Peter Dolding
2008-08-19 8:09 ` douglas.leeder
2008-08-19 11:08 ` Peter Dolding
[not found] ` <20080819114040.2FD1B336880@pmx1.sophos.com>
2008-08-20 3:03 ` Peter Dolding
2008-08-18 16:28 ` douglas.leeder
[not found] <alpine.DEB.1.10.0808180951470.15109@asgard.lang.hm>
2008-08-19 8:31 ` tvrtko.ursulin
2008-08-19 16:07 ` david
2008-08-19 12:34 ` David Collier-Brown
[not found] <20080818101625.85CA12FE876@pmx1.sophos.com>
2008-08-18 10:35 ` douglas.leeder
2008-08-18 12:13 ` david
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