mschap:User-Name and DOM\user versus user at DOM.EXAMPLE.COM

[Phil Mayers]

All,

A few facts first;

Windows seems to "know" about both DOM\user and user at DOM.EXAMPLE.ORG
formats for usernames; when generating an mschap response, it only ever
user the "user" portion.

ntlm_auth seems to take *exactly* what you put into the command line;
that is, it does NO stripping of DOM\user or user at DOM.EXAMPLE.ORG

rlm_mschap registers several expansions, including mschap:User-Name -
this particular expansion performs the following transforms:

host/name.dom.example.org -> name$
DOM\user -> user

I'm wondering if it would be sensible to add the following transform to
the above list:

user at DOM.EXAMPLE.ORG -> user

The rationale being thus: if you want to support both prefix and suffix
forms of the realm *and* machine based auth, you have to use the
slightly non-intuitive syntax:

ntlm_auth --username=%{Stripped-User-Name:-%{mschap:User-Name}}

and have :

modules {
  realm suffix {
    format = suffix
    delimiter = "@"
    ignore_null = yes
  }
  realm ntdomain {
    format = prefix
    delimiter = "\"
    ignore_null = yes
  }
}
authorize {
  preprocess
  prefix
  suffix
  mschap
}

If the @suffix transform were in mschap, it would be possible to
dispense with the realm modules entirely, and just use:

ntlm_auth --username=%{mschap:User-Name}

Comments?