[krbdev.mit.edu #9142] git commit

[Greg Hudson via RT]

<URL: https://krbdev.mit.edu/rt/Ticket/Display.html?id=9142 >


Generate and verify message MACs in libkrad

Implement some of the measures specified in
draft-ietf-radext-deprecating-radius-03 for mitigating the BlastRADIUS
attack (CVE-2024-3596):

* Include a Message-Authenticator MAC as the first attribute when
  generating a packet of type Access-Request, Access-Reject,
  Access-Accept, or Access-Challenge (sections 5.2.1 and 5.2.4), if
  the secret is non-empty.  (An empty secret indicates the use of Unix
  domain socket transport.)

* Validate the Message-Authenticator MAC in received packets, if
  present.

FreeRADIUS enforces Message-Authenticator as of versions 3.2.5 and
3.0.27.  libkrad must generate Message-Authenticator attributes in
order to remain compatible with these implementations.

[ghudson at mit.edu: adjusted style and naming; simplified some
functions; edited commit message]

(cherry picked from commit 871125fea8ce0370a972bf65f7d1de63f619b06c)

https://github.com/krb5/krb5/commit/9c42d20fdc622c022262a4ff677237a1656ce8b6
Author: Julien Rische <jrische at redhat.com>
Committer: Greg Hudson <ghudson at mit.edu>
Commit: 9c42d20fdc622c022262a4ff677237a1656ce8b6
Branch: krb5-1.21
 src/include/k5-int.h                   |   5 +
 src/lib/crypto/krb/checksum_hmac_md5.c |  28 +++++
 src/lib/crypto/libk5crypto.exports     |   1 +
 src/lib/krad/attr.c                    |  17 +++
 src/lib/krad/attrset.c                 |  58 +++++++---
 src/lib/krad/internal.h                |   7 +-
 src/lib/krad/packet.c                  | 205 ++++++++++++++++++++++++++++++---
 src/lib/krad/t_attrset.c               |   2 +-
 src/lib/krad/t_daemon.py               |   3 +-
 src/lib/krad/t_packet.c                |  11 ++
 src/tests/t_otp.py                     |   3 +
 11 files changed, 309 insertions(+), 31 deletions(-)