On 07/03/2017 10:40 AM, Evilham wrote:
<snip>

> That's the thing, we can do that :-) probably should, but the "right
> way" (from a standards point of view) would be to actually allow those
> names ^^ not to disallow them. So instead of modifying the way useradd
> works, the way adduser works should be fixed (so, shadow).

That was easy ;) Seems to be a flag for that.

# adduser 0day --force-badname
Allowing use of questionable username.
Adding user `0day' ...
Adding new group `0day' (1000) ...
Adding new user `0day' (1000) with group `0day' ...
Creating home directory `/home/0day' ...
Copying files from `/etc/skel' ...
Enter new UNIX password: