Date: Tue, 15 Mar 2016 12:08:33 -0600 From: James Gritton <jamie@freebsd.org> To: freebsd-jail@freebsd.org Subject: Re: SHM objects cannot be isolated in jails, any evolution in future FreeBSD versions? Message-ID: <8a3aba735138ade07cad0315dcabee69@gritton.org> In-Reply-To: <593EB477-D6AC-463B-A509-86A63455436F@exonetric.com> References: <c1e2fc0269e9de3a653d6e47da26b026@whitewinterwolf.com> <0ad738494152d249f3bbe3b722a46bd2@gritton.org> <1457989662.568170.549069906.791C2D05@webmail.messagingengine.com> <56E7C926.3020201@quip.cz> <593EB477-D6AC-463B-A509-86A63455436F@exonetric.com>
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On 2016-03-15 06:33, Mark Blackman wrote: > On 15 Mar 2016, at 08:34, Miroslav Lachman <000.fbsd@quip.cz> wrote: >> Mark Felder wrote on 03/14/2016 22:07: >>>> On Sat, Mar 12, 2016, at 11:42, James Gritton wrote: >>>>> 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. >>> >>> Both this and SYSV IPC jail support[1] are badly needed. >>> >>> [1] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=48471 >> >> Yes, it is very sad that original patch was not commited, nor >> commented or improved by core developers for long 13 years. I am not >> 100% sure but I thing there was some patch from PJD for SysV IPC too. >> There were EclipseBSD with resource limits in times of FreeBSD 3.4 and >> there is FreeVPS for 6.x with virtualized IPC... >> >> So I really hope SysV IPC aware jails will become reality soon. >> >> Miroslav Lachman > > Do we have a feeling if this only a funding problem or is it an > enthusiasm problem? > > - Mark More of an "I've been hearing about it being around the corner so haven't done anything" problem. I guess that would file under enthusiasm. - Jamie
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