From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Serge E. Hallyn" Subject: Re: [PATCH 01/15] add Documentation/namespaces/user_namespace.txt (v3) Date: Fri, 9 Sep 2011 08:10:45 -0500 Message-ID: <20110909131045.GB3476@sergelap> References: <1314993400-6910-1-git-send-email-serge@hallyn.com> <1314993400-6910-4-git-send-email-serge@hallyn.com> <20110907155024.42e3fe27.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Serge Hallyn , segooon@gmail.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, containers@lists.linux-foundation.org, dhowells@redhat.com, ebiederm@xmission.com, rdunlap@xenotime.net To: Andrew Morton Return-path: Content-Disposition: inline In-Reply-To: <20110907155024.42e3fe27.akpm@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Quoting Andrew Morton (akpm@linux-foundation.org): > On Fri, 2 Sep 2011 19:56:26 +0000 > Serge Hallyn wrote: > > > +Note that this userid mapping for the VFS is not yet implemented, though the > > +lkml and containers mailing list archives will show several previous > > +prototypes. In the end, those got hung up waiting on the concept of targeted > > +capabilities to be developed, which, thanks to the insight of Eric Biederman, > > +they finally did. > > not-yet-implemented things worry me. When can we expect this to > happen, and how big and ugly will it be? Hi Andrew, We did a proof of concept of the simplest version of this in early August (see git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-userns-devel.git) which actually was very un-scary. So technically we could push it at the same time as this set, but I thought that might just be too much for review in one cycle. That set (Eric's) is the very simplest approach which tags an entire filesystem with a user namespace. We would also want to pursue the more baroque approach, where filesystems themselves are user-namespace aware. I did an approach like that in 2008, see https://lists.linux-foundation.org/pipermail/containers/2008-August/012679.html It again is very do-able without being ugly, but, importantly, user namespaces are usable for containers without that. For starters, we only need /proc and /sys to be user namespace aware (since they must allow access from multiple namespaces), and that is simple as they are not persistent. So I believe that this is the last scary patchset, and that user namespaces could actually be usable by the end of the year! > I'm not seeing many (any) reviewed-by's on these patches. I could get > down and stare at them myself, but that wouldn't be very useful. This > work goes pretty deep and is quite security-affecting. And network-afecting. > Can you round up some suitable people and get the reviewing and testing happening > please? Will try. Unfortunately I missed my chance to beg and bribe people in person at plumbers :( thanks, -serge