Samba includes the user's long-term credentials (encrypted in the AS reply key)
to allow legacy authentication protocols such as NTLM to work even if the
pre-authentication mechanism replaced the reply key (as PKINIT does).
Samba also needs to know whether the client explicitly requested a PAC be
included (or excluded), in order to defer PAC exclusion until a service ticket
is issued (thereby avoiding a name binding attack if the user is renamed
between TGT and service ticket issuance).
References:
https://bugzilla.samba.org/show_bug.cgi?id=11441https://bugzilla.samba.org/show_bug.cgi?id=14561Closes: #864
Original authors:
- Joseph Sutton <josephsutton@catalyst.net.nz>
- Andrew Bartlett <abartlet@samba.org>
- Stefan Metzmacher <metze@samba.org>
This lets us call it from Samba.
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
[abartlet@samba.org Similar to Samba commit 3bdce12789af1e7a7aba56691f184625a432410d
but also fixed for caller in Heimdal windc plugin tests]
Split Windows PAC signing and verification logic, as the signing has to be when
the ticket is ready.
Create sign and verify the PAC KDC signature if the plugin did not, allowing
for S4U2Proxy to work, instead of KRB5SignedPath.
Use the header key to verify PAC server signature, as the same key used to
encrypt/decrypt the ticket should be used for PAC server signature, like U2U
tickets are signed witht the tgt session-key and not with the longterm key,
and so krbtgt should be no different and the header key should be used.
Lookup the delegated client in DB instead of passing the delegator DB entry.
Add PAC ticket-signatures and related functions.
Note: due to the change from KRB5SignedPath to PAC, S4U2Proxy requests
against new KDC will not work if the evidence ticket was acquired from
an old KDC, and vide versa.
Closes: #767
KRB5SignedPath was a Heimdal-specific authorization data element used to
protect the authenticity of evidence tickets when used in constrained
delegation (without a Windows PAC).
Remove this, to be replaced with the Windows PAC which itself now supports
signing the entire ticket in the TGS key.
This was broken with KRB5SignedPath but now that we switch to PAC
we get it fixed without KDC changes, so we can just test it.
See also PR #599 from where these tests were taken.
Add support for GSS-API pre-authentication to the KDC, using a simplified
variation of draft-perez-krb-wg-gss-preauth-02 that encodes GSS-API context
tokens directly in PADATA, and uses FX-COOKIE for state management.
More information on the protocol and implementation may be found in
lib/gssapi/preauth/README.md.
gss_{import,export}_sec_context did not work with partially accumulating
contexts, where the initial context token had not been completely accumulated,
Further, in gss_import_sec_context(), ctx->gc_input.value was not allocated to
a buffer sufficiently large to accumulate the target length.
Microsoft will sometimes split GSS tokens when they exceed a certain
size in some protocols. This is specified in
[MS-SPNG]: Simple and Protected GSS-API Negotiation
Mechanism (SPNEGO) Extension
https://winprotocoldoc.blob.core.windows.net/productionwindowsarchives/MS-SPNG/%5bMS-SPNG%5d.pdf
sections 3.1.5.4 to 3.1.5.9.
We extend gss_accept_sec_context() to recognise partial tokens and
to accumulate the fragments until an entire token is available to
be processed. If the entire token is not yet available,
GSS_S_CONTINUE_NEEDED is returned with a zero length output token.
This is specified in RFC2744 page 25-26 to indicate that no reply
need be sent.
We include updates to the test framework to test split tokens when
using SPNEGO.
Combined with the synthetic_clients feature, this will allow hosts that
have a PKINIT-worthy client certificate with a SAN with their host
principals to create their own principals and "extract" their host
keytabs. Together with some other PKIX credential bootstrapping
protocol, this can help hosts bootstrap Kerberos host credentials.
This is useful for services that need not be clients. For example, an
untrusted service that need only accept authentication from clients,
but not initiate authentication to other services.
- Don't log "Request from wrong address (ignoring)".
- Add "wrongaddr=yes" kv to final log message.
- Add request and ticket addresses (up to 3) to final log message.
This adds support for using a Heimdal-specific PKIX extension to derive
a maximum Kerberos ticket lifetime from a client's PKINIT certificate.
KDC configuration parameters:
- pkinit_max_life_from_cert_extension
- pkinit_max_life_bound
If `pkinit_max_life_from_cert_extension` is set to true then the
certificate extension or EKU will be checked.
If `pkinit_max_life_bound` is set to a positive relative time, then that
will be the upper bound of maximum Kerberos ticket lifetime derived from
these extensions.
The KDC config `pkinit_ticket_max_life_from_cert` that was added earlier
has been renamed to `pkinit_max_life_from_cert`.
See lib/hx509 and lib/krb5/krb5.conf.5.
This adds a KDC configuration parameter that can be used to indicate
that a PKINIT client's certificate's notAfter overrides the client
principal's HDB entry's max_life. This parameter is a relative time
parameter, and it enables this only if set to a non-zero value (defaults
to zero). The value of this parameter caps the max_life inferred from
the certificate.
This is a large commit that adds several features:
- Revamps and moves virtual host-based service principal functionality
from kdc/ to lib/hdb/ so that it may be automatically visible to
lib/kadm5/, as well as kadmin(1)/kadmind(8) and ktutil(1).
The changes are backwards-incompatible.
- Completes support for documenting a service principal's supported
enctypes in its HDB entry independently of its long-term keys. This
will reduce HDB bloat by not requiring that service principals have
more long-term keys than they need just to document the service's
supported enctypes.
- Adds support for storing krb5.conf content in principals' HDB
entries. This may eventually be used for causing Heimdal KDC
services to reconfigure primary/secondary roles automatically by
discovering the configured primary in an HDB entry for the realm.
For now this will be used to help reduce the amount of configuration
needed by clients of an upcoming HTTP binding of the kadmin service.
Add support for SAnon, a simple key agreement protocol that provides no
authentication of initiator or acceptor using x25519 ECDH key exchange.
See doc/standardization/draft-howard-gss-sanon-xx.txt for a protocol
description.
Add the --export-import-context flag to test_context, for validating that
security contexts round-trip through GSS_Export_sec_context() and
GSS_Import_sec_context().
This is needed so that sshd and such can get make practical use of the
"ccache" key in GSS cred stores.
This commit only changes the store path, not the acquisition path.
