Long machine names...

Stephen Langasek vorlon at netexpress.net
Fri May 22 01:58:48 GMT 1998

On Fri, 22 May 1998, Andrew Tridgell wrote:

> > As a question, I'd like to know which UNIXs restrict
> > user names to 8 characters ? Does anyone know which
> > UNIXs don't have this restriction ?

> Lots of unixes _partially_ restrict to 8 chars.

> What I mean by that is that you can stick a longer name in /etc/passwd
> but many utilities won't recognise it. For example, the samba-bugs
> account on samba.anu.edu.au (IRIX 6.4) shows up as samba-bu to finger
> but not to who. Under Linux you can't use talk to an account with a
> long name. There are lots of other little examples.

Well, Linux is relatively easy to fix for this sort of thing, but it's a
sure bet that 9+-char usernames aren't going to work on all currently
deployed Linux systems.  Things like 'talk' and 'who' are of little
consequence for trust accounts, of course, but after one semi-upgrade on
our mailserver (on which we permit long usernames), we found that trying
to log in as one of these users resulted in a successful login as root.
Fortunately, we found it before any of our clients did and fixed the
problem, but who knows how many other implementations out there, linux or
otherwise, might suffer from similar flaws.

                               -Steve Langasek

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