[Adduser-devel] Bug#432562: Bug#432562: adduser --system allow uppercase in usernames without --force-badname

Stephen Gran sgran at debian.org
Tue Jul 10 21:26:30 UTC 2007

tags 432562 +wontfix
This one time, at band camp, Ian Jackson said:
> Several packages have started creating system users whose names
> contain uppercase letters.  

I only know of Debian-exim.  Are there others?

> These names for system users have some advantages over normal names, 
> particularly:
>  * It is easy to tell such a system user from a normal user even
>    if it uses a normal-user-range uid and has a per-user group.

This would be a bug in the maintainer scripts for creating a system user
in the user range.

>  * Mail delivery systems etc. typically won't deliver to such
>    users (because they lowercase the name before lookup)

This is a problem.  Normally system accounts get their email redirected
to a real user via /etc/aliases - if we start creating system accounts
with names that the MTA won't deliver, then we risk losing status email
from the services.  This seem like a bad plan, and is in fact, the main
argument I can see against this idea.

>  * These names do not clash with names created for normal users
>    because normal user-creation tools refuse to create them.

Isn't this precisely what you are asking us to change?

>  * Most other tools behave properly with usernames containing
>    capitals.

Do you know which currently fail?  If any reasonably common pieces of
software misbehave with usernames like this, that is a fairly strong
argument for leaving things as they are, until the software is patched
to not do badly.

> Currently packages that create system users with any uppercase letters
> in the name need to pass --force-badname to adduser.  This is not
> ideal; for example, it gives package maintainers the idea that a name
> with a capital letter is not significantly better than one containing
> punctuation, top-bit-set octets, etc.

Which it seems, from the above, is correct.

> I propose that we relax this restriction.  The attached patch causes
> adduser to allow uppercase letters but only if --system is specified.
> (This is achieved by a separate NAME_REGEX_SYSTEM config option.)
> FYI, this is being deployed in Ubuntu as adduser 3.103ubuntu1.

I await feedback about how the experiment with upper case names goes.
For now, I think I am going to be conservative, sorry.
|   ,''`.                                            Stephen Gran |
|  : :' :                                        sgran at debian.org |
|  `. `'                        Debian user, admin, and developer |
|    `-                                     http://www.debian.org |
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