From owner-freebsd-jail@freebsd.org Sat Mar 12 16:50:01 2016 Return-Path: Delivered-To: freebsd-jail@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 825E3ACE4F2 for ; Sat, 12 Mar 2016 16:50:01 +0000 (UTC) (envelope-from jamie@freebsd.org) Received: from gritton.org (gritton.org [162.220.209.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "www.gritton.org", Issuer "StartCom Class 1 Primary Intermediate Server CA" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 64464CD1 for ; Sat, 12 Mar 2016 16:50:01 +0000 (UTC) (envelope-from jamie@freebsd.org) Received: from gritton.org (gritton.org [162.220.209.3]) by gritton.org (8.15.2/8.15.2) with ESMTPS id u2CGgYXP018541 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Sat, 12 Mar 2016 09:42:34 -0700 (MST) (envelope-from jamie@freebsd.org) Received: (from www@localhost) by gritton.org (8.15.2/8.15.2/Submit) id u2CGgXaA018540; Sat, 12 Mar 2016 09:42:33 -0700 (MST) (envelope-from jamie@freebsd.org) X-Authentication-Warning: gritton.org: www set sender to jamie@freebsd.org using -f To: freebsd-jail@freebsd.org Subject: Re: SHM objects cannot be isolated in jails, any evolution in future FreeBSD versions? X-PHP-Originating-Script: 0:rcube.php MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Sat, 12 Mar 2016 09:42:33 -0700 From: James Gritton In-Reply-To: References: Message-ID: <0ad738494152d249f3bbe3b722a46bd2@gritton.org> X-Sender: jamie@freebsd.org User-Agent: Roundcube Webmail/1.1.2 X-BeenThere: freebsd-jail@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Discussion about FreeBSD jail\(8\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 12 Mar 2016 16:50:01 -0000 On 2016-03-12 04:05, Simon wrote: > The shm_open()(2) function changed since FreeBSD 7.0: the SHM objects > path are now uncorrelated from the physical file system to become just > abstract objects. Probably due to this, the jail system do not provide > any form of filtering regarding shared memory created using this > function. Therefore: > > - Anyone can create unauthorized communication channels between jails, > - Users with enough privileges in any jail can access and modify any > SHM objects system-wide, ie. shared memory objects created in any > other jail and in the host system. > > I've seen a few claims that SHM objects were being handled differently > whether they were created inside or outside a jail. However, I tested > on FreeBSD 10.1 and 9.3 but found no evidence of this: both version > were affected by the same issue. > > A reference of such claim: > https://lists.freebsd.org/pipermail/freebsd-ports-bugs/2015-July/312665.html > > My initial post on FreeBSD forum discussing the issue with more > details: https://forums.freebsd.org/threads/55468/ > > Currently, there does not seem to be any way to prevent this. > > I'm therefore wondering if there are any concrete plans to change this > situation in future FreeBSD versions? Be able to block the currently > free inter-jail SHM-based communication seems a minimum, however such > setting would also most likely prevent SHM-based application to work. > > Using file based SHM objects in jails seemed a good ideas but it does > not seem implemented this way, I don't know why. Is this planned, or > are there any greater plans ongoing also involving IPC's similar > issue? There are no concrete plans I'm aware of, but it's definitely a thing that should be done. How about filing a bug report for it? You've already got a good write-up of the situation. - Jamie