Re: Windows to Cygwin username mapping: Domain before local account when duplicate name?

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Feb 16 18:40, Corinna Vinschen wrote:
> On Feb 16 09:15, Brian Inglis wrote:
> > On 2019-02-16 08:33, Corinna Vinschen wrote:
> > > On Feb 16 08:09, Brian Inglis wrote:
> > >> On 2019-02-16 02:45, Corinna Vinschen wrote:
> > >>> On Feb 15 14:51, Bill Stewart wrote:
> > >>>> On Fri, Feb 15, 2019 at 2:38 PM Brian Inglis wrote:
> > >>>>> Windows normally allows "." to be used to refer to the local machine name in a
> > >>>>> domain context - can anyone confirm or deny whether this works in Cygwin or with
> > >>>>> getent?
> > >>>> AFAICT, the "." shortcut does not work in Cygwin.
> > >>> The combining operator for domain prepended usernames is '+'.  This
> > >>> is the same character as used by good old Interix for the same purpose.
> > >> That was not in question - the question was could .+$USER be used in lieu of
> > >> $COMPUTERNAME+$USER or $HOSTNAME+$USER and should $COMPUTERNAME rather than
> > >> $HOSTNAME be used in such contexts?
> > > Yeah, I misunderstood this, sorry.  The answer is no.  The username is
> > > fixed.  Otherwise you'd have two auto-generated passwd entries for the
> > > same user which may lead to confusion (not necessarily confusion on the
> > > user side...)
> > > If this is a desired feature, we could try this, but it might break
> > > existing setups again.
> > 
> > As with .\$USER in Windows or with ~ for $HOME, this should only be a
> > convenience to allow input or scripts to avoid providing $COMPUTERNAME/$HOSTNAME
> > in userid command line argument contexts.
> 
> I added this to Cygwin for testing so you can simply use ".+username" as
> a shortcut for "$COMPUTERNAME+username".
> 
> I uploaded snapshots to https://cygwin.com/snapshots for playing.

After some mulling, this is a bad idea.  It potentially allows to
circumvent OpenSSHs user/group name matching again, unless the
Admin knows to add every local user twice, e.g.

  Match user MACHINE+user,.+user

or use patterns:

  Match user *+user

I'll revert the patch again.


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer

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