Changes/kerberos-in-python-modernization

Kerberos in Python modernization

Summary

Replace usage of python-krbV and pykerberos with python-gssapi in all Fedora packages to enable their removal from Fedora. rharwood will author all necessary code changes; no new code from maintainers is required.

Owner

• Name: Robbie Harwood
• Email: rharwood at fp dot o
• Release notes ticket: #91

Current status

• Targeted release: Fedora 28
• Last updated: 2018-03-26
• Tracker bug: #1537249

Detailed Description

Replace older, clunkier, less user-friendly python interfaces to Kerberos with python-gssapi. python-gssapi uses the GSSAPI interface, which is widely standardized, implemented by both MIT and Heimdal Kerberos, and much more user-friendly.

As part of this effort, python-requests-gssapi will be introduced to fedora to enable transition off of python-requests-kerberos (which requires pykerberos). Its package review (completed as of 2018-01-03) was rhbz#1527682

Please note that I will be providing all patches necessary to all affected components; no work is expected from other maintainers, other than normal review and backport handling.

Benefit to Fedora

python-krbV has no python3 support, so its replacement helps projects move to python3.

pykerberos is a very minimal implementation intended for use in calendar server and not intended for consumption by other applications. It has almost no documentation.

python-requests-kerberos is largely unmaintained upstream (PRs not getting merged for a very long time; no feedback on python-gssapi for a month). It's also mis-named for what it does, since both it and python-requests-gssapi provide GSSAPI/SPNEGO negotiation support, not just Kerberos.

python-gssapi is substantially more maintainable than python-krbV and pykerberos, and uses the preferred interface to Kerberos (GSSAPI). Its upstream is active (i.e., not dead) and it is hosted in a reasonable way (its own repository on github) that is friendly to new contributors. The project runs PR CI on Fedora explicitly already.

python-requests-gssapi provides a compatability layer for python-requests-kerberos, while also providing a new API that fits much better with projects already using python-gssapi. It is written and maintained by the same group that wrote python-gssapi and apache's mod_auth_gssapi.

Scope

• Proposal owners: rharwood (responsible for providing patches and new package)

• Other developers: maintainers of affected packages are expected to perform code review

• Release engineering: #7219
  • List of deliverables: N/A (not needed for this change)

• Policies and guidelines: N/A (not needed for this Change)

• Trademark approval: N/A (not needed for this Change)

Upgrade/compatibility impact

All dependency changes should be handled seamlessly by dnf without additional input from the user.

How To Test

The following should all produce no results:

dnf repoquery --whatrequires python-krbV

dnf repoquery --whatrequires python-kerberos

dnf repoquery --whatrequires python3-kerberos

User Experience

Change should not be noticeable, except to any users of the deprecated packages directly. dnf should pull in python-gssapi and python-requests-gssapi as appropriate.

Dependencies

All dependencies generated by dnf repoquery --whatrequires packagename.

python-krbV

• beaker-client
• koji-web
• python2-koji

python-kerberos (python{2,3}-kerberos)

• did
• offlineimap
• python2-nitrate
• python-requests-kerberos
• python-urllib2_kerberos
• waiverdb

python-requests-kerberos (python{2,3}-requests-kerberos)

• osbs-client
• python-hdfs
• python2-keystoneclient-kerberos
• python-koji
• python-osbs-client
• python-pdc-client
• retrace-server

python-urllib2_kerberos (python{2,3}-urllib2_kerberos)

• python2-rtkit

Contingency Plan

• Contingency mechanism: Ship them. python-krbV removal is highest priority since no python3 support.
• Contingency deadline: Beta
• Blocks release? No
• Blocks product? No

Documentation

python-gssapi docs can be found on its github page

requests-gssapi docs can be found on its github

Release Notes

This change did not fully land for Fedora28, but a large part of it did, and the rest will be proposed in the future. In particular:

• koji did not deploy their python-gssapi code, and no beaker changeset was proposed, so python-krbV remains.
• did was migrated to python-gssapi.
• offlineimap migrated to python-gssapi.
• python-nitrate was migrated to python-gssapi.
• waiverdb has a changeset, but it wasn't proposed in time, so it doesn't make fc28.
• python-requests-gssapi was introduced to replace python-requests-kerberos
• python-urllib-gssapi was introduced to replace python-urllib2_kerberos
• python-kerberos therefore remains until python-urllib2_kerberos and python-requests-kerberos can be removed.
• python2-rtkit has a changeset, but it wasn't proposed in time, so python-urllib2_kerberos can't be removed yet.