freeipa/ipaserver/install
Julien Rische 3f1b373cb2 Tolerate absence of PAC ticket signature depending of server capabilities
Since November 2020, Active Directory KDC generates a new type of
signature as part of the PAC. It is called "ticket signature", and is
generated based on the encrypted part of the ticket. The presence of
this signature is not mandatory in order for the PAC to be accepted for
S4U requests.

However, the behavior is different for MIT krb5. Support was added as
part of the 1.20 release, and this signature is required in order to
process S4U requests. Contrary to the PAC extended KDC signature, the
code generating this signature cannot be isolated and backported to
older krb5 versions because this version of the KDB API does not allow
passing the content of the ticket's encrypted part to IPA.

This is an issue in gradual upgrade scenarios where some IPA servers
rely on 1.19 and older versions of MIT krb5, while others use version
1.20 or newer. A service ticket that was provided by 1.19- IPA KDC will
be rejected when used by a service against a 1.20+ IPA KDC for S4U
requests.

On Fedora, CentOS 9 Stream, and RHEL 9, when the krb5 version is 1.20 or
newer, it will include a downstream-only update adding the
"optional_pac_tkt_chksum" KDB string attribute allowing to tolerate the
absence of PAC ticket signatures, if necessary.

This commit adds an extra step during the installation and update
processes where it adds a "pacTktSignSupported" ipaConfigString
attribute in "cn=KDC,cn=[server],cn=masters,cn=ipa,cn=etc,[basedn]" if
the MIT krb5 version IPA what built with was 1.20 or newer.

This commit also set "optional_pac_tkt_chksum" as a virtual KDB entry
attribute. This means the value of the attribute is not actually stored
in the database (to avoid race conditions), but its value is determined
at the KDC starting time by search the "pacTktSignSupported"
ipaConfigString in the server list. If this value is missing for at
least of them is missing, enforcement of the PAC ticket signature is
disabled by setting "optional_pac_tkt_chksum" to true for the local
realm TGS KDB entry.

For foreign realm TGS KDB entries, the "optional_pac_tkt_chksum" virtual
string attribute is set to true systematically, because, at least for
now, trusted AD domains can still have PAC ticket signature support
disabled.

Given the fact the "pacTktSignSupported" ipaConfigString for a single
server is added when this server is updated, and that the value of
"optional_pac_tkt_chksum" is determined at KDC starting time based on
the ipaConfigString attributes of all the KDCs in the domain, this
requires to restart all the KDCs in the domain after all IPA servers
were updated in order for PAC ticket signature enforcement to actually
take effect.

Fixes: https://pagure.io/freeipa/issue/9371
Signed-off-by: Julien Rische <jrische@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
2023-05-24 13:20:38 +02:00
..
plugins Generate CNAMEs for TXT+URI location krb records 2022-11-23 20:00:17 +01:00
server Tolerate absence of PAC ticket signature depending of server capabilities 2023-05-24 13:20:38 +02:00
__init__.py Remove __all__ specifications in ipaclient and ipaserver.install 2013-09-06 15:42:33 +02:00
adtrust.py adtrust install: define constants for rid bases 2021-11-02 10:11:28 +01:00
adtrustinstance.py Ignore empty modification error in case cifs/.. principal already added 2023-04-05 14:55:22 -04:00
bindinstance.py LDAP autobind authenticateAsDN for BIND named 2021-06-15 14:13:16 +03:00
ca.py Add support for Random Serial Numbers v3 2022-06-09 08:35:15 +02:00
cainstance.py Explicitly use legacy ID generators by default 2022-11-03 15:18:30 -04:00
certs.py cert utilities: MAC verification is incompatible with FIPS mode 2022-12-19 15:38:05 +01:00
conncheck.py install: introduce installer class hierarchy 2016-11-11 12:17:25 +01:00
custodiainstance.py pylint: Fix unused-private-member 2022-03-11 13:37:08 -05:00
dns.py pylint: Fix useless-suppression 2022-03-11 13:37:08 -05:00
dnskeysyncinstance.py dnskeysyncinstance: use late binding for UID/GID resolution 2020-12-22 14:05:13 +02:00
dogtag.py Verify pki ini override early 2019-04-10 13:43:23 +02:00
dogtaginstance.py Remove extraneous AJP secret from server.xml on upgrades 2022-06-14 15:54:50 +03:00
dsinstance.py Speed up installer by restarting DS after DNA plugin 2023-04-17 15:15:09 -04:00
httpinstance.py pylint: Replace deprecated pipes 2023-01-10 08:30:58 +01:00
installutils.py pylint: Fix used-before-assignment 2023-01-10 08:30:58 +01:00
ipa_acme_manage.py Fix setting values of 0 in ACME pruning 2023-02-09 13:28:23 -05:00
ipa_backup.py BIND: Setup logging 2021-05-25 10:45:49 +03:00
ipa_cacert_manage.py ipa-cacert-manage prune: remove all expired certs 2022-09-23 09:49:06 +02:00
ipa_cert_fix.py ipa-cert-fix man page: add note about certmonger renewal 2021-06-10 20:59:27 +02:00
ipa_crlgen_manage.py CRL generation master: new utility to enable|disable 2019-03-14 09:39:55 +01:00
ipa_kra_install.py Change FreeIPA references to IPA and Identity Management 2021-01-21 13:51:45 +01:00
ipa_ldap_updater.py Remove -s option from ipa-ldap-updater usage 2021-05-20 14:45:27 -04:00
ipa_otptoken_import.py pylint: Fix useless-object-inheritance 2023-01-10 08:30:58 +01:00
ipa_pkinit_manage.py Allow PKINIT to be enabled when updating from a pre-PKINIT IPA CA server 2021-06-17 17:28:48 -04:00
ipa_replica_install.py pylint: Fix useless-suppression 2022-03-11 13:37:08 -05:00
ipa_restore.py pylint: Fix useless-suppression 2022-03-11 13:37:08 -05:00
ipa_server_certinstall.py Require an ipa-ca SAN on 3rd party certs if ACME is enabled 2020-11-02 14:01:05 -05:00
ipa_server_install.py pylint: Fix useless-suppression 2022-03-11 13:37:08 -05:00
ipa_server_upgrade.py ipa commands: print 'IPA is not configured' when ipa is not setup 2018-08-23 12:08:45 +02:00
ipa_subids.py pylint: Fix arguments-renamed 2022-03-11 13:37:08 -05:00
ipa_trust_enable_agent.py ipa-adtrust-install: run remote configuration for new agents 2020-03-05 14:40:58 +01:00
ipa_winsync_migrate.py ipa commands: print 'IPA is not configured' when ipa is not setup 2018-08-23 12:08:45 +02:00
ipactl.py pylint: Fix useless-suppression 2022-03-11 13:37:08 -05:00
kra.py ipa-kra-install: exit if ca_host is overriden 2021-07-27 13:27:36 +02:00
krainstance.py Explicitly use legacy ID generators by default 2022-11-03 15:18:30 -04:00
krbinstance.py Tolerate absence of PAC ticket signature depending of server capabilities 2023-05-24 13:20:38 +02:00
ldapupdate.py pylint: remove useless suppression 2023-01-10 08:30:58 +01:00
odsexporterinstance.py odsexporterinstance: use late binding for UID/GID resolution 2020-12-22 14:05:13 +02:00
opendnssecinstance.py opendnssecinstance: use late binding for UID/GID resolution 2020-12-22 14:05:13 +02:00
otpdinstance.py Enable pylint missing-final-newline check 2015-12-23 07:59:22 +01:00
replication.py check_repl_update: in progress is a boolean 2022-08-16 08:39:06 +02:00
schemaupdate.py Unify access to FQDN 2020-10-26 17:11:19 +11:00
service.py LDAP autobind authenticateAsDN for BIND named 2021-06-15 14:13:16 +03:00
sysupgrade.py Add absolute_import future imports 2018-04-20 09:43:37 +02:00
upgradeinstance.py Use get_replication_plugin_name in LDAP updater 2021-06-21 10:58:02 +02:00