From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932983AbZHDQVk (ORCPT ); Tue, 4 Aug 2009 12:21:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932970AbZHDQVk (ORCPT ); Tue, 4 Aug 2009 12:21:40 -0400 Received: from pmx1.sophos.com ([213.31.172.16]:59564 "EHLO pmx1.sophos.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932913AbZHDQVi (ORCPT ); Tue, 4 Aug 2009 12:21:38 -0400 X-Greylist: delayed 706 seconds by postgrey-1.27 at vger.kernel.org; Tue, 04 Aug 2009 12:21:38 EDT From: Tvrtko Ursulin Organization: Sophos Plc To: Eric Paris Subject: Re: fanotify - overall design before I start sending patches Date: Tue, 4 Aug 2009 17:09:50 +0100 User-Agent: KMail/1.9.10 Cc: "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "malware-list@dmesg.printk.net" , "Valdis.Kletnieks@vt.edu" , "greg@kroah.com" , "jcm@redhat.com" , Douglas Leeder , "tytso@mit.edu" , "arjan@infradead.org" , "david@lang.hm" , "jengelh@medozas.de" , "aviro@redhat.com" , "mrkafk@gmail.com" , "alexl@redhat.com" , "jack@suse.cz" , "a.p.zijlstra@chello.nl" , "hch@infradead.org" , "alan@lxorguk.ukuu.org.uk" , "mmorley@hcl.in" , "pavel@suse.cz" References: <1248466429.3567.82.camel@localhost> In-Reply-To: <1248466429.3567.82.camel@localhost> MIME-Version: 1.0 Message-Id: <200908041709.51659.tvrtko.ursulin@sophos.com> X-MIMETrack: Itemize by SMTP Server on Mercury/Servers/Sophos(Release 7.0.3|September 26, 2007) at 04/08/2009 17:09:52, Serialize by Router on Mercury/Servers/Sophos(Release 7.0.3|September 26, 2007) at 04/08/2009 17:09:52, Serialize complete at 04/08/2009 17:09:52 X-TNEFEvaluated: 1 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="iso-8859-1" Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eric, all, On Friday 24 July 2009 21:13:49 Eric Paris wrote: > If a FAN_ACCESS_PERM or FAN_OPEN_PERM event is received the listener > must send a response before the 5 second timeout. If no response is > sent before the 5 second timeout the original operation is allowed. If > this happens too many times (10 in a row) the fanotify group is evicted > from the kernel and will not get any new events. Sending a response is Would it make more sense to deny on timeouts and then evict? I am thinking it would be more secure with no significant drawbacks. Also for usages like HSM allowing it without data being in place might present wrong content to the user. > The only other current interface is the ability to ignore events by > superblock magic number. This makes it easy to ignore all events > in /proc which can be difficult to accomplish firing FANOTIFY_SET_MARK > with ignored_masks over and over as processes are created and destroyed. Just to double-check, that would also work for any other filesystem and is controllable from userspace? Tvrtko