From: Nikolay Borisov <kernel@kyup.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: john@johnmccutchan.com, eparis@parisplace.org,
viro@zeniv.linux.org.uk, jack@suse.cz, serge@hallyn.com,
avagin@openvz.org, linux-kernel@vger.kernel.org,
containers@lists.linux-foundation.org
Subject: Re: [PATCH] inotify: Convert to using per-namespace limits
Date: Mon, 10 Oct 2016 09:44:19 +0300 [thread overview]
Message-ID: <57FB38C3.9090803@kyup.com> (raw)
In-Reply-To: <8737k86n7q.fsf@x220.int.ebiederm.org>
On 10/07/2016 09:14 PM, Eric W. Biederman wrote:
> Nikolay Borisov <kernel@kyup.com> writes:
>
>> This patchset converts inotify to using the newly introduced
>> per-userns sysctl infrastructure.
>>
>> Currently the inotify instances/watches are being accounted in the
>> user_struct structure. This means that in setups where multiple
>> users in unprivileged containers map to the same underlying
>> real user (i.e. pointing to the same user_struct) the inotify limits
>> are going to be shared as well, allowing one user(or application) to exhaust
>> all others limits.
>>
>> Fix this by switching the inotify sysctls to using the
>> per-namespace/per-user limits. This will allow the server admin to
>> set sensible global limits, which can further be tuned inside every
>> individual user namespace.
>>
>> Signed-off-by: Nikolay Borisov <kernel@kyup.com>
>> ---
>> Hello Eric,
>>
>> I saw you've finally sent your pull request for 4.9 and it
>> includes your implementatino of the ucount infrastructure. So
>> here is my respin of the inotify patches using that.
>
> Thanks. I will take a good hard look at this after -rc1 when things are
> stable enough that I can start a new development branch.
>
> I am a little concerned that the old sysctls have gone away. If no one
> cares it is fine, but if someone depends on them existing that may count
> as an unnecessary userspace regression. But otherwise skimming through
> this code it looks good.
So this indeed this is real issue and I meant to write something about
it. Anyway, in order to preserve those sysctl what can be done is to
hook them up with a custom sysctl handler taking the ns from the proc
mount and the euid of current? I think this is a good approach, but
let's wait and see if anyone will have objections to completely
eliminating those sysctls.
>
[SNIP]
next prev parent reply other threads:[~2016-10-10 6:44 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 10:46 [PATCH] inotify: Convert to using per-namespace limits Nikolay Borisov
2016-10-07 18:14 ` Eric W. Biederman
2016-10-10 6:44 ` Nikolay Borisov [this message]
2016-10-10 16:40 ` Jan Kara
2016-10-10 20:49 ` Eric W. Biederman
2016-10-10 21:54 ` Nikolay Borisov
2016-10-10 22:39 ` Eric W. Biederman
2016-10-11 7:36 ` [PATCH v2] " Nikolay Borisov
2016-10-14 2:31 ` [lkp] [inotify] 464e1236c3: BUG kmalloc-512 (Not tainted): Freepointer corrupt kernel test robot
2016-10-24 6:47 ` [PATCH v2] inotify: Convert to using per-namespace limits Nikolay Borisov
2016-10-27 15:46 ` Eric W. Biederman
2016-12-08 1:40 ` Eric W. Biederman
2016-12-08 6:58 ` Nikolay Borisov
2016-12-08 8:14 ` Nikolay Borisov
2016-12-09 5:38 ` Eric W. Biederman
2016-12-09 2:50 ` Eric W. Biederman
2016-10-24 7:48 ` Jan Kara
2016-11-14 6:04 ` Serge E. Hallyn
2016-10-09 5:55 ` [lkp] [inotify] 1109954e99: BUG kmalloc-512 (Not tainted): Freepointer corrupt kernel test robot
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