The "-f" dump option allows a dump of the Heimdal
KDC in a format that the MIT kdb5_util command can
load into a MIT KDC's database.
This makes transitioning from the Heimdal KDC to
the current MIT one feasible without having to
re-create the KDC database from scratch.
glebius@ did the initial work, cherry picking these
commits from the Heimdal sources on github and then doing
extensive merge conflict resolution and other fixes so
that it would build.
Heimdal commit fca5399 authored by Nico Williams:
Initial commit for second approach for multiple kvno. NOT TESTED!
Heimdal commit 57f1545 authored by Nico Williams:
Add support for writing to KDB and dumping HDB to MIT KDB dump format
Before this change Heimdal could read KDBs. Now it can write to
them too.
Heimdal can now also dump HDBs (including KDBs) in MIT format,
which can then be imported with kdb5_util load.
This is intended to help in migrations from MIT to Heimdal by
allowing migrations from Heimdal to MIT so that it is possible
to rollback from Heimdal to MIT should there be any issues. The
idea is to allow a) running Heimdal kdc/kadmind with a KDB, or
b) running Heimdal with an HDB converted from a KDB and then
rollback by dumping the HDB and loading a KDB.
Note that not all TL data types are supported, only two: last
password change and modify-by. This is the minimum necessary.
PKINIT users may need to add support for KRB5_TL_USER_CERTIFICATE,
and for databases with K/M history we may need to add KRB5_TL_MKVNO
support.
This resulted in a Heimdal kadmin that would dump
the KDC database in MIT format. However, there
were issues when this dump was loaded into the
current MIT KDC in FreeBSD current/15.0.
The changes I did to make the dump more useful are listed below:
When "-f MIT" is used for "kadmin -l dump" it writes
the dump out in MIT format. This dump format is understood
by the MIT kdb5_util command. The patch modifies the above
so that the MIT KDC's master key keytab file can be provided
as the argument to "-f" so that the principals are re-encrypted in
it. This allows any principal with at least one strong encryption
type key to work without needing a change_password.
The strong encryption types supported by the Heimdal KDC are:
aes256-cts-hmac-sha1-96
aes128-cts-hmac-sha1-96
The issues my changes address are:
- If there are weak encryption keys in a principal's entry,
MIT's kadmin.local will report that the principcal's entry
is incomplete or corrupted.
- The keys are encrypted in Heimdal's master key. The
"-d" option can be used on the "kadmin -l dump" to
de-encrypt them, but the passwords will not work on the
current MIT KDC.
To try and deal with the above issues, this patch modied the above to:
- Does not dump the weak keys.
- Re-encrypts the strong keys in MIT's master key if the argument
to "-f" is actually a filename which holds the MIT KDC's
master key keytab and not "MIT".
- For principals that only have weak keys, it generates
a fake strong key. This key will not work on the MIT
KDC, but the principal entry will work once a
change_password is done to it.
- It always generates a "modified_by" entry, faking one if
not already present in the Heimdal KDC database.
This was necessary, since the MIT kadmin will
report that the principal entry is "incomplete or
corrupted" without one.
It also fixed a problem where "get principal" no longer
worked after the initial patch was applied.
A man page update will be done as a separate commit.
I believe this commit is acceptable since the Heimdal
sources are now essentially deprecated in favor of the
MIT sources and that this new "-f" patch simplifies
the transition to the MIT KDC.
Discussed with: glebius, cy
MFC after: 3 days
several new kerberos related libraries and applications to FreeBSD:
o kgetcred(1) allows one to manually get a ticket for a particular service.
o kf(1) securily forwards ticket to another host through an authenticated
and encrypted stream.
o kcc(1) is an umbrella program around klist(1), kswitch(1), kgetcred(1)
and other user kerberos operations. klist and kswitch are just symlinks
to kcc(1) now.
o kswitch(1) allows you to easily switch between kerberos credentials if
you're running KCM.
o hxtool(1) is a certificate management tool to use with PKINIT.
o string2key(1) maps a password into key.
o kdigest(8) is a userland tool to access the KDC's digest interface.
o kimpersonate(8) creates a "fake" ticket for a service.
We also now install manpages for some lirbaries that were not installed
before, libheimntlm and libhx509.
- The new HEIMDAL version no longer supports Kerberos 4. All users are
recommended to switch to Kerberos 5.
- Weak ciphers are now disabled by default. To enable DES support (used
by telnet(8)), use "allow_weak_crypto" option in krb5.conf.
- libtelnet, pam_ksu and pam_krb5 are now compiled with error on warnings
disabled due to the function they use (krb5_get_err_text(3)) being
deprecated. I plan to work on this next.
- Heimdal's KDC now require sqlite to operate. We use the bundled version
and install it as libheimsqlite. If some other FreeBSD components will
require it in the future we can rename it to libbsdsqlite and use for these
components as well.
- This is not a latest Heimdal version, the new one was released while I was
working on the update. I will update it to 1.5.2 soon, as it fixes some
important bugs and security issues.
Rick Macklem