From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: [RFC] lsm: namespace hooks Date: Thu, 27 Nov 2014 10:44:39 -0600 Message-ID: <871tooy4nc.fsf@x220.int.ebiederm.org> References: <1417096866-25563-1-git-send-email-l.pawelczyk@samsung.com> <1417096866-25563-2-git-send-email-l.pawelczyk@samsung.com> <1417098928.1805.15.camel@samsung.com> <54773757.8090905@nod.at> <1417099455.1805.17.camel@samsung.com> <54773CE7.5040303@nod.at> <1417101060.1805.21.camel@samsung.com> <87d288zm3a.fsf@x220.int.ebiederm.org> <1417104439.1805.25.camel@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1417104439.1805.25.camel-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> (Lukasz Pawelczyk's message of "Thu, 27 Nov 2014 17:07:19 +0100") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Lukasz Pawelczyk Cc: Vladimir Davydov , Miklos Szeredi , Lukasz Pawelczyk , LKML , David Howells , Mark Rustad , Matthew Dempsky , Richard Weinberger , Daeseok Youn , Ingo Molnar , Jeff Kirsher , David Rientjes , Alex Thorlton , Juri Lelli , Kees Cook , Nikolay Aleksandrov , Dario Faggioli , Al Viro , James Morris , "open lis t:ABI/API" , Linux Containers , Oleg Nesterov , Paul Moore List-Id: linux-api@vger.kernel.org Lukasz Pawelczyk writes: > On czw, 2014-11-27 at 09:42 -0600, Eric W. Biederman wrote: >> Lukasz Pawelczyk writes: >> >> > On czw, 2014-11-27 at 16:01 +0100, Richard Weinberger wrote: >> >> Am 27.11.2014 um 15:44 schrieb Lukasz Pawelczyk: >> >> > True, the last one is 0x80000000. I did not notice that. Thanks for >> >> > pointing out. >> >> >> >> Isn't this CLONE_IO? >> > >> > Yes, I was merely noticing out loud that it's the last bit of 32bit. >> > >> > After close look though the 0x00001000 appears to be unused >> > >> >> > Any suggestion on what can be done here? New syscal with flags2? >> >> >> >> I'm not sure. But a new syscall would be a candidate. >> >> We are probably going to need to go a couple rounds with this but at >> first approximation I think this functionality needs to be tied to the >> user namespace. This functionality already looks half tied to it. >> >> When mounting filesystems with user namespaces priveleges matures a >> little more you should be able to use unmapped labels. In the near term >> we are looking at filesystems such as tmpfs, fuse and posibly extN. > > I presume you are referring to the Smack namespace readme where I > mentioned mounts with specifying smack labels in the mount options, not > to the quote above? > > I was referring the to the check here that has been changed to > smack_ns_privileged() using ns_capable(): > http://lxr.free-electrons.com/source/security/smack/smack_lsm.c#L462 > > And you can't use an unmapped Smack label inside the namespace, this > would be completely against its idea. > > Anyway, at this point I'm more interested in the LSM namespace. I'll be > doing an RFC for Smack namespace later. > > Unless I misunderstood your mail. I had two points. a) Tie the label mapping to the user namespace, then we don't need any new namespaces. Is there a reason not to tie the label mapping to the user namespace? Needing to modify every userspace that create containers to know about every different lsm looks like a maintenance difficulty I would prefer to avoid. b) For filesystems that don't need uid mapping (say ext2 mounted with user namespace permissions) we shouldn't need LSM mapping either. Eric