Re: plan9 semantics on Linux - mount namespaces

[Richard Weinberger]

On Wed, Feb 14, 2018 at 12:27 PM, Enrico Weigelt <lkml@xxxxxxxxx> wrote:
> On 14.02.2018 11:24, Aleksa Sarai wrote:
>
>> What distribution are you using and which release?
>
>
> On a self-compiled system.
>
> Forgot to enable namespaces in the kernel. Now it seems to work
> as root, but not as an unprivileged user:
>
>
> daemon@alphabox:~ unshare -r -U
> unshare: can't open '/proc/self/setgroups': Permission denied
> daemon@alphabox:~ unshare -f -r -U
> unshare: can't open '/proc/self/setgroups': Permission denied
>

Please read http://man7.org/linux/man-pages/man7/user_namespaces.7.html
setgroups is a corner case and needs special care.

-- 
Thanks,
//richard