From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Paris Subject: Re: fanotify - overall design before I start sending patches Date: Tue, 04 Aug 2009 12:27:48 -0400 Message-ID: <1249403268.2361.21.camel@dhcp231-106.rdu.redhat.com> References: <1248466429.3567.82.camel@localhost> <200908041709.51659.tvrtko.ursulin@sophos.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "david-gFPdbfVZQbY@public.gmane.org" , "a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org" , "Valdis.Kletnieks-PjAqaU27lzQ@public.gmane.org" , Douglas Leeder , "malware-list-h+Im9A44IAFcMpApZELgcQ@public.gmane.org" , "mrkafk-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org" , "aviro-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , "jack-AlSwsSmVLrQ@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "jengelh-nopoi9nDyk+ELgA04lAiVw@public.gmane.org" , "hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org" , "pavel-AlSwsSmVLrQ@public.gmane.org" , "alexl-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , "jcm-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , "linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "alan-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org" , "arjan-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org" To: Tvrtko Ursulin Return-path: In-Reply-To: <200908041709.51659.tvrtko.ursulin-j34lQMj1tz/QT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: malware-list-bounces-h+Im9A44IAFcMpApZELgcQ@public.gmane.org Errors-To: malware-list-bounces-h+Im9A44IAFcMpApZELgcQ@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org On Tue, 2009-08-04 at 17:09 +0100, Tvrtko Ursulin wrote: > 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. I'd be willing to go that route as long as noone else complains. > > 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? Yes you set these in userspace using setsockopt(). It is based on superblock magic number as found in linux/magic.h. So one could exclude, procfs, sysfs, selinuxfs, etc. It does not provide a way to say 'this ext3 filesystem but not that ext3 filesystem' as ext3 has a single magic number.