Re: [PATCH 2/2] net: Implement SO_PEERCGROUP

From: Andy Lutomirski
Date: Thu Mar 13 2014 - 15:58:46 EST


On Thu, Mar 13, 2014 at 12:53 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> On Thu, Mar 13, 2014 at 10:55:16AM -0700, Andy Lutomirski wrote:
>
> [..]
>> >> 2. Docker is a container system, so use the "container" (aka
>> >> namespace) APIs. There are probably several clever things that could
>> >> be done with /proc/<pid>/ns.
>> >
>> > pid is racy, if it weren't I would simply go straight
>> > to /proc/<pid>/cgroups ...
>>
>> How about:
>>
>> open("/proc/self/ns/ipc", O_RDONLY);
>> send the result over SCM_RIGHTS?
>
> As I don't know I will ask. So what will server now do with this file
> descriptor of client's ipc namespace.
>
> IOW, what information/identifier does it contain which can be
> used to map to pre-configrued per container/per namespace policies.

Inode number, which will match that assigned to the container at runtime.

(I'm not sure this is a great idea -- there's no convention that "I
have an fd for a namespace" means "I'm a daemon in that namespace".)

--Andy

>
> Thanks
> Vivek



--
Andy Lutomirski
AMA Capital Management, LLC
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