Testing on hosts with firewalls

[Florian Weimer]

On 12/30/2016 10:28 AM, Andreas Schwab wrote:
> On Dez 29 2016, Mike Frysinger <vapier@gentoo.org> wrote:
>
>> $ unshare -Urn
>
> unshare: write failed /proc/self/gid_map: Operation not permitted

There would have to be fallback code for older/restricted kernels.  Some 
distributions disable user namespaces in various ways because they have 
been shown to expand the kernel attack surface significantly.

If this is a current upstream kernel with user namespaces enabled, I 
would be worried, though.

Florian