Re: [GIT PULL] Namespace file descriptors for 2.6.40

["Michał Mirosław" <mirqus@gmail.com>]

2011/5/25 C Anthony Risinger <anthony@xtfx.me>:
> On Wed, May 25, 2011 at 4:38 PM, Serge E. Hallyn <serge@hallyn.com> wrote:
>> Quoting C Anthony Risinger (anthony@xtfx.me):
[...]
>>> if i understand correctly, mount namespaces (for example), allow one
>>> to build such constructs as "private /tmp" and similar that even
>>> `root` cannot access ... and there are many reasons `root` does not
>>> deserve to completely know/interact with user processes (FUSE makes a
>>> good example ... just because i [user] have SSH access to a machine,
>>> why should `root`?)
>> If for instance you have a file open in your private /tmp, then root
>> in another mounts ns can open the file through /proc/$$/fd/N anyway.
>> If it's a directory, he can now traverse the whole fs.
> aaah right :-( ... there's always another way isn't there ... curse
> you Linux for being so flexible! (just kidding baby i love you)
>
> this seems like a more fundamental issue then?  or should i not expect
> to be able to achieve separation like this?  i ask in the context of
> OS virt via cgroups + namespaces, eg. LXC et al, because i'm about to
> perform a massive overhaul to our crusty sub-2.6.18 infrastructure and
> i've used/followed these technologies for couple years now ... and
> it's starting to feel like "the right time".

You either trust the admin or don't use the machine. There is no third way.

Best Regards,
Michał Mirosław