path: root/README

                   Kerberos Version 5, Release 1.21

                            Release Notes
                        The MIT Kerberos Team

Copyright and Other Notices
---------------------------

Copyright (C) 1985-2023 by the Massachusetts Institute of Technology
and its contributors.  All rights reserved.

Please see the file named NOTICE for additional notices.

Documentation
-------------

Unified documentation for Kerberos V5 is available in both HTML and
PDF formats.  The table of contents of the HTML format documentation
is at doc/html/index.html, and the PDF format documentation is in the
doc/pdf directory.

Additionally, you may find copies of the HTML format documentation
online at

    https://web.mit.edu/kerberos/krb5-latest/doc/

for the most recent supported release, or at

    https://web.mit.edu/kerberos/krb5-devel/doc/

for the release under development.

More information about Kerberos may be found at

    https://web.mit.edu/kerberos/

and at the MIT Kerberos Consortium web site

    https://kerberos.org/

Building and Installing Kerberos 5
----------------------------------

Build documentation is in doc/html/build/index.html or
doc/pdf/build.pdf.

The installation guide is in doc/html/admin/install.html or
doc/pdf/install.pdf.

If you are attempting to build under Windows, please see the
src/windows/README file.

Reporting Bugs
--------------

Please report any problems/bugs/comments by sending email to
krb5-bugs@mit.edu.

You may view bug reports by visiting

https://krbdev.mit.edu/rt/

and using the "Guest Login" button.  Please note that the web
interface to our bug database is read-only for guests, and the primary
way to interact with our bug database is via email.

PAC transitions
---------------

Beginning with release 1.20, the KDC will include minimal PACs in
tickets instead of AD-SIGNEDPATH authdata.  S4U requests (protocol
transition and constrained delegation) must now contain valid PACs in
the incoming tickets.  Beginning with release 1.21, service ticket
PACs will contain a new KDC checksum buffer, to mitigate a hash
collision attack against the old KDC checksum.  If only some KDCs in a
realm have been upgraded across versions 1.20 or 1.21, the upgraded
KDCs will reject S4U requests containing tickets from non-upgraded
KDCs and vice versa.

Triple-DES and RC4 transitions
------------------------------

Beginning with the krb5-1.21 release, the KDC will not issue tickets
with triple-DES or RC4 session keys unless explicitly configured using
the new allow_des3 and allow_rc4 variables in [libdefaults].  To
facilitate the negotiation of session keys, the KDC will assume that
all services can handle aes256-sha1 session keys unless the service
principal has a session_enctypes string attribute.

Beginning with the krb5-1.19 release, a warning will be issued if
initial credentials are acquired using the des3-cbc-sha1 encryption
type.  Beginning with the krb5-1.21 release, a warning will also be
issued for the arcfour-hmac encryption type.  In future releases,
these encryption types will be disabled by default and eventually
removed.

Beginning with the krb5-1.18 release, all support for single-DES
encryption types has been removed.

Major changes in 1.21 (2023-06-05)
----------------------------------

User experience:

* Added a credential cache type providing compatibility with the macOS
  11 native credential cache.

Developer experience:

* libkadm5 will use the provided krb5_context object to read
  configuration values, instead of creating its own.

* Added an interface to retrieve the ticket session key from a GSS
  context.

Protocol evolution:

* The KDC will no longer issue tickets with RC4 or triple-DES session
  keys unless explicitly configured with the new allow_rc4 or
  allow_des3 variables respectively.

* The KDC will assume that all services can handle aes256-sha1 session
  keys unless the service principal has a session_enctypes string
  attribute.

* Support for PAC full KDC checksums has been added to mitigate an
  S4U2Proxy privilege escalation attack.

* The PKINIT client will advertise a more modern set of supported CMS
  algorithms.

Code quality:

* Removed unused code in libkrb5, libkrb5support, and the PKINIT
  module.

* Modernized the KDC code for processing TGS requests, the code for
  encrypting and decrypting key data, the PAC handling code, and the
  GSS library packet parsing and composition code.

* Improved the test framework's detection of memory errors in daemon
  processes when used with asan.

krb5-1.21 changes by ticket ID
------------------------------

9052    Support macOS 11 native credential cache
9053    Make kprop work for dump files larger than 4GB
9054    Replace macros with typedefs in gssrpc types.h
9055    Use SHA-256 instead of SHA-1 for PKINIT CMS digest
9057    Omit LDFLAGS from krb5-config --libs output
9058    Add configure variable for default PKCS#11 module
9059    Use context profile for libkadm5 configuration
9066    Set reasonable supportedCMSTypes in PKINIT
9069    Update error checking for OpenSSL CMS_verify
9071    Add and use ts_interval() helper
9072    Avoid small read overrun in UTF8 normalization
9076    Use memmove() in Unicode functions
9077    Fix aclocal.m4 syntax error for autoconf 2.72
9078    Fix profile crash on memory exhaustion
9079    Fix preauth crash on memory exhaustion
9080    Fix gic_keytab crash on memory exhaustion
9082    Fix policy DB fallback error handling
9083    Fix kpropd crash with unrecognized option
9084    Add PAC full checksums
9085    Fix read overruns in SPNEGO parsing
9086    Fix possible double-free during KDB creation
9087    Fix meridian type in getdate.y
9088    Use control flow guard flag in Windows builds
9089    Add pac_privsvr_enctype string attribute
9090    Convey realm names to certauth modules
9091    Add GSS_C_INQ_ODBC_SESSION_KEY
9092    Fix maintainer-mode build for binutils 2.37
9093    Add PA-REDHAT-PASSKEY padata type

Acknowledgements
----------------

Past Sponsors of the MIT Kerberos Consortium:

    Apple
    Carnegie Mellon University
    Centrify Corporation
    Columbia University
    Cornell University
    The Department of Defense of the United States of America (DoD)
    Fidelity Investments
    Google
    Iowa State University
    MIT
    Michigan State University
    Microsoft
    MITRE Corporation
    Morgan-Stanley
    The National Aeronautics and Space Administration
        of the United States of America (NASA)
    Network Appliance (NetApp)
    Nippon Telephone and Telegraph (NTT)
    US Government Office of the National Coordinator for Health
        Information Technology (ONC)
    Oracle
    Pennsylvania State University
    Red Hat
    Stanford University
    TeamF1, Inc.
    The University of Alaska
    The University of Michigan
    The University of Pennsylvania

Past and present members of the Kerberos Team at MIT:

    Danilo Almeida
    Jeffrey Altman
    Justin Anderson
    Richard Basch
    Mitch Berger
    Jay Berkenbilt
    Andrew Boardman
    Bill Bryant
    Steve Buckley
    Joe Calzaretta
    John Carr
    Mark Colan
    Don Davis
    Sarah Day
    Alexandra Ellwood
    Carlos Garay
    Dan Geer
    Nancy Gilman
    Matt Hancher
    Thomas Hardjono
    Sam Hartman
    Paul Hill
    Marc Horowitz
    Eva Jacobus
    Miroslav Jurisic
    Barry Jaspan
    Benjamin Kaduk
    Geoffrey King
    Kevin Koch
    John Kohl
    HaoQi Li
    Jonathan Lin
    Peter Litwack
    Scott McGuire
    Steve Miller
    Kevin Mitchell
    Cliff Neuman
    Paul Park
    Ezra Peisach
    Chris Provenzano
    Ken Raeburn
    Jon Rochlis
    Jeff Schiller
    Jen Selby
    Robert Silk
    Bill Sommerfeld
    Jennifer Steiner
    Ralph Swick
    Brad Thompson
    Harry Tsai
    Zhanna Tsitkova
    Ted Ts'o
    Marshall Vale
    Taylor Yu

The following external contributors have provided code, patches, bug
reports, suggestions, and valuable resources:

    Ian Abbott
    Daniel Albers
    Brandon Allbery
    Russell Allbery
    Brian Almeida
    Michael B Allen
    Pooja Anil
    Jeffrey Arbuckle
    Heinz-Ado Arnolds
    Derek Atkins
    Mark Bannister
    David Bantz
    Alex Baule
    Nikhil Benesch
    David Benjamin
    Thomas Bernard
    Adam Bernstein
    Arlene Berry
    Jeff Blaine
    Toby Blake
    Radoslav Bodo
    Alexander Bokovoy
    Sumit Bose
    Emmanuel Bouillon
    Isaac Boukris
    Ulf Bremer
    Pavel Březina
    Philip Brown
    Samuel Cabrero
    Michael Calmer
    Andrea Campi
    Julien Chaffraix
    Puran Chand
    Ravi Channavajhala
    Srinivas Cheruku
    Leonardo Chiquitto
    Rachit Chokshi
    Seemant Choudhary
    Howard Chu
    Andrea Cirulli
    Christopher D. Clausen
    Kevin Coffman
    Simon Cooper
    Sylvain Cortes
    Ian Crowther
    Arran Cudbard-Bell
    Adam Dabrowski
    Jeff D'Angelo
    Nalin Dahyabhai
    Mark Davies
    Dennis Davis
    Alex Dehnert
    Misty De Meo
    Mark Deneen
    Günther Deschner
    John Devitofranceschi
    Marc Dionne
    Roland Dowdeswell
    Ken Dreyer
    Dorian Ducournau
    Viktor Dukhovni
    Jason Edgecombe
    Mark Eichin
    Shawn M. Emery
    Douglas E. Engert
    Peter Eriksson
    Juha Erkkilä
    Gilles Espinasse
    Sergey Fedorov
    Ronni Feldt
    Bill Fellows
    JC Ferguson
    Remi Ferrand
    Paul Fertser
    Fabiano Fidêncio
    Frank Filz
    William Fiveash
    Jacques Florent
    Oliver Freyermuth
    Ákos Frohner
    Sebastian Galiano
    Marcus Granado
    Dylan Gray
    Norm Green
    Scott Grizzard
    Helmut Grohne
    Steve Grubb
    Philip Guenther
    Timo Gurr
    Dominic Hargreaves
    Robbie Harwood
    John Hascall
    Jakob Haufe
    Matthieu Hautreux
    Jochen Hein
    Paul B. Henson
    Kihong Heo
    Jeff Hodges
    Christopher Hogan
    Love Hörnquist Åstrand
    Ken Hornstein
    Henry B. Hotz
    Luke Howard
    Jakub Hrozek
    Shumon Huque
    Jeffrey Hutzelman
    Sergey Ilinykh
    Wyllys Ingersoll
    Holger Isenberg
    Spencer Jackson
    Diogenes S. Jesus
    Mike Jetzer
    Pavel Jindra
    Brian Johannesmeyer
    Joel Johnson
    Lutz Justen
    Ganesh Kamath
    Alexander Karaivanov
    Anders Kaseorg
    Bar Katz
    Zentaro Kavanagh
    Mubashir Kazia
    W. Trevor King
    Patrik Kis
    Martin Kittel
    Thomas Klausner
    Tomasz Kłoczko
    Matthew Krupcale
    Mikkel Kruse
    Reinhard Kugler
    Harshawardhan Kulkarni
    Tomas Kuthan
    Pierre Labastie
    Andreas Ladanyi
    Chris Leick
    Volker Lendecke
    Jan iankko Lieskovsky
    Todd Lipcon
    Oliver Loch
    Chris Long
    Kevin Longfellow
    Frank Lonigro
    Jon Looney
    Nuno Lopes
    Todd Lubin
    Ryan Lynch
    Glenn Machin
    Roland Mainz
    Sorin Manolache
    Robert Marshall
    Andrei Maslennikov
    Michael Mattioli
    Nathaniel McCallum
    Greg McClement
    Cameron Meadors
    Vipul Mehta
    Alexey Melnikov
    Ivan A. Melnikov
    Franklyn Mendez
    Mantas Mikulėnas
    Markus Moeller
    Kyle Moffett
    Paul Moore
    Keiichi Mori
    Michael Morony
    Sam Morris
    Zbysek Mraz
    Edward Murrell
    Joshua Neuheisel
    Nikos Nikoleris
    Demi Obenour
    Felipe Ortega
    Michael Osipov
    Andrej Ota
    Dmitri Pal
    Javier Palacios
    Dilyan Palauzov
    Tom Parker
    Eric Pauly
    Leonard Peirce
    Ezra Peisach
    Alejandro Perez
    Zoran Pericic
    W. Michael Petullo
    Mark Phalan
    Sharwan Ram
    Brett Randall
    Jonathan Reams
    Jonathan Reed
    Robert Relyea
    Tony Reix
    Martin Rex
    Pat Riehecky
    Julien Rische
    Jason Rogers
    Matt Rogers
    Nate Rosenblum
    Solly Ross
    Mike Roszkowski
    Guillaume Rousse
    Joshua Schaeffer
    Alexander Scheel
    Jens Schleusener
    Ryan Schmidt
    Andreas Schneider
    Paul Seyfert
    Tom Shaw
    Jim Shi
    Jerry Shipman
    Peter Shoults
    Richard Silverman
    Cel Skeggs
    Simo Sorce
    Michael Spang
    Michael Ströder
    Bjørn Tore Sund
    Ondřej Surý
    Joseph Sutton
    Joe Travaglini
    Sergei Trofimovich
    Greg Troxel
    Fraser Tweedale
    Tim Uglow
    Rathor Vipin
    Denis Vlasenko
    Thomas Wagner
    Jorgen Wahlsten
    Stef Walter
    Max (Weijun) Wang
    John Washington
    Stef Walter
    Xi Wang
    Nehal J Wani
    Kevin Wasserman
    Margaret Wasserman
    Marcus Watts
    Andreas Wiese
    Simon Wilkinson
    Nicolas Williams
    Ross Wilper
    Augustin Wolf
    Garrett Wollman
    David Woodhouse
    Tsu-Phong Wu
    Xu Qiang
    Neng Xue
    Zhaomo Yang
    Tianjiao Yin
    Nickolai Zeldovich
    Bean Zhang
    ChenChen Zhou
    Hanz van Zijst
    Gertjan Zwartjes

The above is not an exhaustive list; many others have contributed in
various ways to the MIT Kerberos development effort over the years.