F36 Change: Drop NIS(+) support from PAM (System-Wide Change proposal)

[Ben Cotton]

https://fedoraproject.org/wiki/Changes/drop_NIS_support_from_PAM

== Summary ==

This change is about dropping user-authentication using NIS(+) from PAM.

== Owner ==

* Name: [[User:besser82 | Björn Esser]]
* Email: [e-mail]
* Name: [[User:ipedrosa | Iker Pedrosa]]
* Email: [e-mail]

== Detailed Description ==
NIS(+) was introduced by Sun/Oracle to easily share files and system
users between UNIX-alike systems within the same network, and has been
around for some decades. Its simplicity though opens a variety of
possible security issues, like not being able the verify whether the
shared information is actually correct and/or trustworthy. That said,
and with several more secure options (LDAP, Kerberos, Samba, etc.) to
achieve the same goal, we should at least remove support for NIS for
user authentication.

== Feedback ==
There was some discussion on
[https://lists.fedoraproject.org/archives/list/[e-mail]/...
the fedora-devel mailing-list].  Some people are reluctant about the
removal of NIS(+) support from PAM, while most are okay with it as
there are more secure alternatives (LDAP, FreeIPA, etc.) available.

== Benefit to Fedora ==
With this change we start directing our users and developers to move
away from NIS(+) to secure alternatives like LDAP and/or FreeIPA.

== Scope ==
* Proposal owners:
** Adapt the pam spec file to build without support for NIS(+).
** Communicate the removal of the PAM configuration for
user-authentication using NIS with the authselect maintainers; also
offer assistance to implement the needed changes.
* Other developers:
** Apply the pull-request to the authselect package.
** Test this change.
* Release engineering: [https://pagure.io/releng/issue/10351 #10351]
* Policies and guidelines: N/A (not needed for this Change)
* Trademark approval: N/A (not needed for this Change)
* Alignment with Objectives: N/A

== Upgrade/compatibility impact ==
Users that were relying on support for NIS(+) will need to move to
secure alternatives like LDAP and/or FreeIPA.

== How To Test ==
There is no need to test, as when configure switch is removed, support
is dropped.

== User Experience ==
For some users this change may be a bit disruptive and it may require
some learning curve for switching to alternative solutions.

== Dependencies ==
* The authselect package needs to be updated to drop its PAM
configuration for user-authentication using NIS.
* Apart from that there are actually no rpms, that directly depend on
the change of the functionality of the affected PAM module.

== Contingency Plan ==
* Contingency mechanism: Revert the changes made to the affected
packages and rebuild them.
* Contingency deadline: At beta freeze.
* Blocks release? Yes.

== Documentation ==
The documentation about sharing system users and files over NIS should
be dropped, if there even is any.

== Release Notes ==
Support for NIS(+) has been dropped from PAM.  Users, who are
currently using NIS(+) to share UNIX users / groups within a network,
should migrate their setups to use LDAP or some other secure service
providing comparable functionalities before updating to Fedora 36.