Re: unshare -m for non-root user

[Mike Frysinger <vapier@gentoo.org>]

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On 15 Nov 2015 13:06, U.Mutlu wrote:
> Mike Frysinger wrote on 11/15/2015 07:28 AM:
> > On 15 Nov 2015 03:10, U.Mutlu wrote:
> >> Mike Frysinger wrote on 11/15/2015 02:24 AM:
> >>> On 15 Nov 2015 01:49, U.Mutlu wrote:
> >>>> So, then the question remains: how to give non-root user a secure mount
> >>>
> >>> no, it doesn't.  at least two people have already told you how to do it:
> >>> use the usernamespace (-U) option that unshare already supports.
> >>
> >> It's not yet clear for me how to use that. Can you give an example?
> >> unshare -U /bin/bash
> >
> > the unshare(1) man page already includes an example:
> > $ unshare --map-root-user --user sh -c whoami
> > root
> 
> No, firstly there is no such example in man unshare, secondly it doesn't do here:
> $ unshare --map-root-user --user sh -c whoami
> unshare: unshare failed: Operation not permitted
> 
> Is there maybe a bug in the Debian version?

complain to Debian.  iirc, they break their kernels on purpose by adding
non-standard caps which disallow userns usage.

> And thirdly: is that not even more dangerous to give a user root permission 
> then? I don't understand this philosophy. Or, where is the trick in this?

you aren't actually root.  you'll probably want to read:
	https://lwn.net/Articles/532593/
	man user_namespaces
-mike

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