National/unicode characters in login name

[Peter Schober]

* Tobias Galéus <tobias.galeus at gu.se> [2018-03-02 12:08]:
> For example gugalto, gügältô and gugałtö all works as a username for
> my password.

ldapwhoami does the same thing for me, i.e. I could substitute "ſ"
(long lowercase s) for "s" in a login name and still authenticate
correctly only using LDAP tools/APIs. ("š" for s did not work though.)

Seems the IDP has no choice to prevent this if the backend auth system
accecpts it.

-peter