From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [patch 0/1][NETNS49] Make af_unix autobind per namespace Date: Tue, 02 Oct 2007 22:51:51 +0200 Message-ID: <4702AF67.1010707@fr.ibm.com> References: <20071002151846.827206013@mai.toulouse-stg.fr.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: 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: "Eric W. Biederman" Cc: containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org, den-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, benjamin.thery-6ktuUTfB/bM@public.gmane.org List-Id: containers.vger.kernel.org Eric W. Biederman wrote: > Daniel Lezcano writes: > >> The following patch change autobind fonction to use the ordernum >> from the network namespace instead of using the local static variable. > > Why do we care? > Information leak? > Some application is expecting a predictable autobind value? > > Just skimming the code it looks like it will work correctly without > this. I think my summary is ... too short :) I don't see any applications taking care of this. If they ask for an abstract socket, then they don't care about the bind result. So probably, the patchset is totally useless. But from the POV of the checkpoint/restart, we should check if this value is somewhere visible from userspace and so storable by an application. It appears this is the case with /proc/net/unix, where an abstract socket is symbolized by the path pattern "@". Example: cat /proc/net/unix Num RefCount Protocol Flags Type St Inode Path c6a27710: 00000002 00000000 00000000 0002 01 4357 @00003 I agree by the fact that can be considered as a detail and the probability to have an application storing this informaton is very small ( eg. checkpointing while doing netstat in the container ). But IMHO, the paradigm "never seen from userspace" fails and that justifies to have the ordernum variable relative to a namespace. -- Daniel