Modify ipadb_reinit_mspac() to allocate and initialize ipactx->mspac
only if all its attributes can be set. If not, ipactx->mspac is set to
NULL. This makes easier to determine if the KDC is able to generate PACs
or not.
Also ipadb_reinit_mspac() is now able to return a status message
explaining why initialization of the PAC generator failed. This message
is printed in KDC logs.
Fixes: https://pagure.io/freeipa/issue/9535
Signed-off-by: Julien Rische <jrische@redhat.com>
Reviewed-By: Alexander Bokovoy <abbra@users.noreply.github.com>
Samba 4.20 will change name extension of the private libraries from
'samba4' to 'private-samba'. Detect private extension through configure
step and make sure to use the right library name in Makefile.
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
krbCanonicalName is mandatory for services but IPA services created
before commit e6ff83e (FreeIPA 4.4.0, ~2016) had no normalization done
to set krbCanonicalName; services created after that version were
upgraded to do have krbCanonicalName.
Accept krbPrincipalName alone since they have no alias either */
Fixes: https://pagure.io/freeipa/issue/9465
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
Reviewed-By: Thierry Bordaz <tbordaz@redhat.com>
PKINIT differs from other pre-authentication methods by the fact that it
can be matched indepedently of the user authentication types via certmap
plugin in KDC.
Since PKINIT is a strong authentication method, allow its authentication
indicator and only apply the ticket policy.
Fixes: https://pagure.io/freeipa/issue/9485
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Francisco Trivino <ftrivino@redhat.com>
If default user authentication type is set to a list that does not
include a password or a hardened credential, the resulting configuration
might be incorrect for special service principals, including a krbtgt/..
one.
Add detection of special principals to avoid these situations and always
allow password or hardened for services.
Special handling is needed for the following principals:
- krbtgt/.. -- TGT service principals
- K/M -- master key principal
- kadmin/changepw -- service for changing passwords
- kadmin/kadmin -- kadmin service principal
- kadmin/history -- key used to encrypt history
Additionally, implicitly allow password or hardened credential use for
IPA services and IPA hosts since applications typically use keytabs for
that purpose.
Fixes: https://pagure.io/freeipa/issue/9485
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Francisco Trivino <ftrivino@redhat.com>
Adding proper error handling to the is_master_host() function to allow
it to make the difference between the absence of a master host object
and a connection failure. This will keep the krb5kdc daemon from
continuing to run with a NULL LDAP context.
Fixes: https://pagure.io/freeipa/issue/9422
Signed-off-by: Julien Rische <jrische@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
MIT Kerberos KDC code will do verification of the PAC full checksum
buffers, we don't need to process them. This change only applies to
newer MIT Kerberos version which have this buffer type defined, hence
using #ifdef to protect the use of the define.
This should have no functional difference.
Related: https://pagure.io/freeipa/issue/9371
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Julien Rische <jrische@redhat.com>
Kerberos principal aliases lookup had a long-standing TODO item to
support server referrals for host-based aliases. This commit implements
server referrals for hosts belonging to trusted domains. The use-case is
a part of S4U processing in a two-way trust when an IPA service requests
a ticket to a host in a trusted domain (e.g. service on AD DC). In such
situation, the server principal in TGS request will be a normal principal
in our domain and KDC needs to respond with a server referral. This
referral can be issued by a KDB driver or by the KDC itself, using
'domain_realms' section of krb5.conf. Since KDB knows all suffixes
associated with the trusted domains, implement the logic there.
Fixes: https://pagure.io/freeipa/issue/9164
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Julien Rische <jrische@redhat.com>
Postpone ticket checksum configuration after KDB module was initialized.
This, in practice, should now happen when a master key is retrieved.
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Julien Rische <jrische@redhat.com>
Early in startup LDAP server might not respond well yet and
should_support_pac_tkt_sign() will bail out with
KRB5_KDB_SERVER_INTERNAL_ERR. We should postpone this call but for time
being we should prevent a crash.
Crash happens because init_module() returns with an error and KDC then
calls fini_module() which will free the DB context which is already
corrupted for some reason.
Do not call any free() call because the whole context is corrupted as
tests do show.
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Julien Rische <jrische@redhat.com>
From https://krbdev.mit.edu/rt/Ticket/Display.html?id=9089
--------
The KDC uses the first local TGT key for the privsvr and full PAC
checksums. If this key is of an aes-sha2 enctype in a cross-realm
TGT, a Microsoft KDC in the target realm may reject the ticket because
it has an unexpectedly large privsvr checksum buffer. This behavior
is unnecessarily picky as the target realm KDC cannot and does not
need to very the privsvr checksum, but [MS-PAC] 2.8.2 does limit the
checksum key to three specific enctypes.
--------
Use MIT Kerberos 1.21+ facility to hint about proper enctype for
cross-realm TGT.
Fixes: https://pagure.io/freeipa/issue/9124
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Julien Rische <jrische@redhat.com>
- added passkey detection based on the presence of ipaPassKey attribute
in the LDAP entry of the principal
- added 'passkey' authentication indicator
- added support for enforcing KDC policy based on the 'passkey'
indicator
Fixes: https://pagure.io/freeipa/issue/9263
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Commit f78dc0b163 was missing an exception for the constrained
delegation ACL TL data type during the principal entry update operation.
This ACL is not meant to be stored as encoded data in krbExtraData.
Signed-off-by: Julien Rische <jrische@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
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>
In November 2022, Microsoft introduced a new PAC signature type called
"extended KDC signature" (or "full PAC checksum"). This new PAC
signature will be required by default by Active Directory in July 2023
for S4U requests, and opt-out will no longer be possible after October
2023.
Support for this new signature type was added to MIT krb5, but it relies
on the new KDB API introduced in krb5 1.20. For older MIT krb5 versions,
the code generating extended KDC signatures cannot be backported as it
is without backporting the full new KDB API code too. This would have
too much impact to be done.
As a consequence, krb5 packages for Fedora 37, CentOS 8 Stream, and RHEL
8 will include a downstream-only update adding the
krb5_pac_full_sign_compat() function, which can be used in combination
with the prior to 1.20 KDB API to generate PAC extended KDC signatures.
Fixes: https://pagure.io/freeipa/issue/9373
Signed-off-by: Julien Rische <jrische@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Resource-based constrained delegation (RBCD) is implemented with a new
callback used by the KDC. This callback is called when a server asks for
S4U2Proxy TGS request and passes a ticket that contains RBCD PAC
options.
The callback is supposed to take a client and a server principals, a PAC and a target
service database entry. Using the target service database entry it then
needs to decide whether a server principal is allowed to delegate the
client credentials to the target service.
The callback can also cross-check whether the client principal can be
limited in delegating own tickets but this is not implemented in the
current version.
Fixes: https://pagure.io/freeipa/issue/9354
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Confine search for S4U2Proxy access control lists to the subtree where
they created. This will allow to use a similar method to describe RBCD
access controls.
Related: https://pagure.io/freeipa/issue/5444
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
When PAC check is performed, we might get a signing TGT instead of the
client DB entry. This means it is a principal from a trusted domain but
we don't know which one exactly because we only have a krbtgt for the
forest root. This happens in MIT Kerberos 1.20 or later where KDB's
issue_pac() callback never gets the original client principal directly.
Look into known child domains as well and make pass the check if both
NetBIOS name and SID correspond to one of the trusted domains under this
forest root. Move check for the SID before NetBIOS name check because we
can use SID of the domain in PAC to find out the right child domain in
our trusted domains' topology list.
Fixes: https://pagure.io/freeipa/issue/9316
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rafael Guterres Jeffman <rjeffman@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
With MIT krb5 1.20, a call to krb5_db_check_allowed_to_delegate()
and krb5_db_check_allowed_to_delegate_from() expects to return either
KRB5KDC_ERR_BADOPTION for a policy denial or KRB5_PLUGIN_OP_NOTSUPP in
case plugin does not handle the policy case. This is part of the MIT
krb5 commit a441fbe329ebbd7775eb5d4ccc4a05eef370f08b which added a
minimal MS-PAC generator.
Prior to MIT krb5 1.20, the same call was expected to return either
KRB5KDC_ERR_POLICY or KRB5_PLUGIN_OP_NOTSUPP errors.
Related: https://pagure.io/freeipa/issue/9083
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
PAC requester check was incorrect for in-realm S4U operations. It casted
too wide check which denied some legitimate requests. Fix that by only
applying rejection to non-S4U unknown SIDs, otherwise S4U2Self request
issued by the in-realm service against a trusted domain's user would not
work.
Related: https://pagure.io/freeipa/issue/9083
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Julien Rische <jrische@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
With krb5 1.20, S4U processing code uses a special case of passing an
empty S4U proxy to allowed_to_delegate() callback to identify if the
server cannot get forwardable S4U2Self tickets according to [MS-PAC]
3.2.5.1.2.
This means we need to ensure NULL proxy is a valid one and return an
appropriate response to that.
Fixes: https://pagure.io/freeipa/issue/9083
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Julien Rische <jrische@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
For generating PAC we need to know SID of the object and a number of
required attributes. However, trusted domain objects do not have these
attributes. Luckily, IPA LDAP schema puts them under actual trust
objects which have all the additional (POSIX) attributes.
Refactor PAC generator to accept secondary LDAP entry and use that one
to pull up required attributes. We only use this for trusted domain
objects.
Fixes: https://pagure.io/freeipa/issue/9083
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Julien Rische <jrische@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Currently if a certificate mapping and matching rule has a typo or is of
an unsupported type the whole rule processing is aborted and the IPA
certmap plugin works without any rules effectively disabling PKINIT for
users. Since each rule would only allow more certificates for PKINIT it
would be more user/admin friendly to just ignore the failed rules with a
log message and continue with what is left or use the default rule if
nothing is left.
This change is done to add more flexibility to define new mapping and
matching templates which are e.g. needed to cover changes planned by
Microsoft as explained in
https://support.microsoft.com/en-us/topic/kb5014754-certificate-based-authentication-changes-on-windows-domain-controllers-ad2c23b0-15d8-4340-a468-4d4f3b188f16
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
For a well-known anonymous principal an Anonymous PKINIT method is used
which ignores the password set in the principal entry. For these
principals any defined user auth type is irrelevant, their use is
defined in RFC 6112. This gets confusing when a default user auth type
requires a particular authentication method.
When AS request for Anonymous PKINIT is used, a TGT would contain no
authentication indicator. It means we cannot apply any specific
indicator policy and must skip the checks.
Fixes: https://pagure.io/freeipa/issue/9165
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>
This will allow custom hardened password policy to be applied.
Without this then the policy will be skipped because the UA
is not enabled.
The KDC and client will prefer SPAKE any time it is available.
For IPA this should mean we should choose hardened setting over a
default one any time SPAKE is used.
Related: https://pagure.io/freeipa/issue/9121
Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
When IdP configuration is provided, take it into account:
- idp-specific Kerberos ticket policy would be applied
- Presence of IdP link in a Kerberos principal entry would cause KDB to
enable `idp` pre-authentication method on KDC side.
The latter requires additional pre-authentication method supplied with
SSSD 2.7.0.
Fixes: https://pagure.io/freeipa/issue/8804
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Signed-off-by: Pavel Březina <pbrezina@redhat.com>
Reviewed-By: Francisco Trivino <ftrivino@redhat.com>
Reviewed-By: Sumit Bose <sbose@redhat.com>
Since 5d51ae5, principal keys were dropped in case user auth indicator
was not including password. Thereafter, the key removal behavior was
removed by 15ff9c8 in the context of the kdcpolicy plugin introduction.
Support for hardened pre-auth methods (FAST and SPAKE) was added in
d057040, and the removal of principal keys was restored afterwards by
f0d12b7, but not taking the new hardened auth indicator into account.
Fixes: https://pagure.io/freeipa/issue/9065
Related to: https://pagure.io/freeipa/issue/8001
Signed-off-by: Julien Rische <jrische@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Francisco Trivino <ftrivino@redhat.com>
MIT Kerberos 1.20 changes DAL interface around PAC record issuance:
sign_authdata callback is removed and replaced with issue_pac one.
The signatures are different and logic changed as well.
Prepare for KDB version 9 by moving PAC implementation into separate
source files. ipa_kdb_mspac.c is left with most of the common code.
FreeIPA supports sign_authdata callback since KDB version 6, move current
implementation to ipa_kdb_mspac_v6.c.
KDB version 8 actually changed sign_authdata interface and we accounted
to that in ipa_kdb.c with a stub that re-uses v6 version. Keep it as it
is right now.
Finally, add KDB version 9 stub files. Compiling against MIT Kerberos
1.20 does not work yet, thus explicit #error message in ipa_kdb.c. This
will be worked on later.
Related: https://pagure.io/freeipa/issue/9083
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
New versions of MS-KILE and MS-SFU after Windows Server November 2021
security updates add PAC_REQUESTER_SID buffer check behavior:
- PAC_REQUESTER_SID should only be added for TGT requests
- if PAC_REQUESTER_SID is present, KDC must verify that the cname on
the ticket resolves to the account with the same SID as the
PAC_REQUESTER_SID. If it doesn't KDC must respond with
KDC_ERR_TKT_REVOKED
Change requester SID check to skip exact check for non-local
PAC_REQUESTER_SID but harden to ensure it comes from the trusted domains
we know about.
If requester SID is the same as in PAC, we already do cname vs PAC SID
verification.
With these changes FreeIPA works against Windows Server 2019 with
November 2021 security fixes in cross-realm S4U2Self operations.
Fixes: https://pagure.io/freeipa/issue/9031
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
MS-KILE 3.3.5.6.4.8 in revision after Windows Server November 2021
security fixes added the following requirement:
- PAC_REQUESTER_SID is only added in TGT case (including referrals and
tickets to RODCs)
Fixes: https://pagure.io/freeipa/issue/9031
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Due to a bug in GCC 9 and GCC 10 optimizing code, all C library
comparison functions should be used with explicit result comparison in
the code to avoid problems described in
http://r6.ca/blog/20200929T023701Z.htmlhttps://gcc.gnu.org/bugzilla/show_bug.cgi?id=95189
The code below is affected:
```
if (strcmp(a, b) || !strcmp(c, d)) ...
```
while the code below is not affected:
```
if (strcmp(a, b) != 0 || strcmp(c, d)) == 0
```
for all C library cmp functions and related:
- strcmp(), strncmp()
- strcasecmp(), strncasecmp()
- stricmp(), strnicmp()
- memcmp()
This PR idea is based on the pull request by 'Nicolas Williams <nico@twosigma.com>'
to Heimdal Kerberos: https://github.com/heimdal/heimdal/pull/855
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Previously, ipadb_check_logon_info() was called only for cross-realm
case. Now we call it for both in-realm and cross-realm cases. In case of
the S4U2Proxy, we would be passed a PAC of the original caller which
might be a principal from the trusted realm. We cannot validate that PAC
against our local client DB entry because this is the proxy entry which
is guaranteed to have different SID.
In such case, validate the SID of the domain in PAC against our realm
and any trusted doman but skip an additional check of the DB entry in
the S4U2Proxy case.
Related: https://pagure.io/freeipa/issue/9031
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
If the SID was explicitly set for the host or service entry, honor it
when issuing PAC. For normal services and hosts we don't allocate
individual SIDs but for cifs/... principals on domain members we do as
they need to login to Samba domain controller.
Related: https://pagure.io/freeipa/issue/9031
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
As part of CVE-2020-25717 mitigations, Samba expects correct user
account flags in the PAC. This means for services and host principals we
should be using ACB_WSTRUST or ACB_SVRTRUST depending on whether they
run on IPA clients ("workstation" or "domain member") or IPA servers
("domain controller").
Fixes: https://pagure.io/freeipa/issue/9031
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
PAC_ATTRIBUTES_INFO PAC buffer allows both client and KDC to tell
whether a PAC structure was requested by the client or it was provided
by the KDC implicitly. Kerberos service then can continue processing or
deny access in case client explicitly requested to operate without PAC.
Fixes: https://pagure.io/freeipa/issue/9031
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
CVE-2020-25721 mitigation: KDC must provide the new PAC_REQUESTER_SID
buffer with ObjectSID value associated with the requester's principal.
The mitigation only works if NDR library supports the PAC_REQUESTER_SID
buffer type. In case we cannot detect it at compile time, a warning will
be displayed at configure stage.
Fixes: https://pagure.io/freeipa/issue/9031
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
CVE-2020-25721 mitigation: KDC must provide the new HAS_SAM_NAME_AND_SID
buffer with sAMAccountName and ObjectSID values associated with the
principal.
The mitigation only works if NDR library supports the
PAC_UPN_DNS_INFO_EX buffer type. In case we cannot detect it at compile
time, a warning will be displayed at configure stage.
Fixes: https://pagure.io/freeipa/issue/9031
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
Julien Rische
Alexander Bokovoy
Florence Blanc-Renaud
Rafael Guterres Jeffman
Sumit Bose
Rob Crittenden