Add a helper function that returns TRUE if a PAC should be included in ticket
authorization data, that can be called from both AS and TGS paths.
Per [MS-KILE] 3.3.5.3, PACs are always included for TGTs; for service
tickets, policy is governed by whether the client explicitly requested
a PAC be omitted when requesting a TGT, or if the no-auth-data-reqd
flag is set on the service principal entry.
Distinguish pre-authentication mechanisms that replace the reply key from those
that use the client's long-term key. In the general case, one is the inverse of
the other, however KRB5_PADATA_ENCRYPTED_CHALLENGE replaces the reply-key with
one derived from the long-term key.
PA_REPLACE_REPLY_KEY indicates that the kvno should be set to zero in the
reply; the absence of PA_USES_LONG_TERM_KEY indicates that the client's
long-term key may be included in the PAC (PAC_CREDENTIAL_INFO with Samba only).
Corrects e8984871.
Distinguish pre-authentication mechanisms that replace the reply key from those
that use the client's long-term key. In the general case, one is the inverse of
the other, however KRB5_PADATA_ENCRYPTED_CHALLENGE replaces the reply-key with
one derived from the long-term key.
PA_REPLACE_REPLY_KEY indicates that the kvno should be set to zero in the
reply; the absence of PA_USES_LONG_TERM_KEY indicates that the client's
long-term key may be included in the PAC (PAC_CREDENTIAL_INFO with Samba only).
PACs are included when issuing TGTs, if there is no PAC_ATTRIBUTES buffer
(legacy behavior) or if the attributes buffer indicates the AS client requested
one.
Only include the PAC_ATTRIBUTES PAC info buffer if we are issuing a TGT, as its
contents are not relevant to application services. (The buffer contains a bit
indicating whether the client explicitly or implicitly requested a PAC.)
Update the sample GSS pre-authentication authorizer plugin to allow the PAC to
be pinned to the authenticating user's SID.
There is still a race condition between the time the user authenticates and the
time the SID is looked up via LDAP, but it should be sufficient as an example;
if more security is required, then users should be enrolled with their SIDs.
Note the selected pre-authentication mechanism, and add a callback to allow the
pre-authentication mechanism to update the PAC immediately prior to signing.
Add PAC_ATTRIBUTES_INFO to the PAC. This info buffer indicates whether the user
explicitly requested a PAC be present or absent.
Note: this changes the windc plugin ABI.
Use the UPN_DNS_INFO buffer of the PAC to include the canonical principal name.
Arguably we should use AD-LOGIN-ALIAS as defined in RFC6806, but we may not
always know all the principal's aliases, and this approach allows us to share
application service logic with Windows.
08e0305b introduced a patch to validate armor ticket PACs, but required that
the armor client principal was in the local realm (as it did not allow
_kdc_db_fetch() to fail).
Allow cross-realm FAST armor clients by using the same logic to look up the
client principal as the TGS itself does, i.e. use db_fetch_client() which
handles the case where the client is not local to the KDC.
Note: the armor PAC is only required to be validated when issuing a final,
non-referral service ticket, as this is the only point upon which device claims
should be inserted (according to my understanding).
Closes: #901
Add a new authorization data type to indicate a synthetic principal was used,
to allow synthetic clients acquired outside of PKINIT (e.g. with GSS-API
pre-authentication) to use the TGS.
Note: we continue to honor KRB5_AUTHDATA_INITIAL_VERIFIED_CAS to indicate that
it is OK for the client to be synthetic, even though it is only an indication
that the client *may* have been synthetic.
If the pre-authentication mechanism replaced the reply key, then the kvno in
the KDC-REP should be zero, as the reply is not encrypted in the client's
(versioned) long-term key.
Closes: #899
We now pass on the original client name and the client address to allow
consistent audit logging in Samba across multiple protocols.
We also log the authentication duration.
This is not a general purpose profiling solution, but in Smaba
these JSON logs are already being generated and stored, so this
is worth adding.
Some administrators are very keen to know how long authentication
takes, particularly due to long replication transactions in other
Samba processes.
We use config->db[0] to find the first database to record incorrect
users.
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
(Similar to Samba commit f498ba77df2313e78863e5f2706840c43e232a96 and
bb2a1c6b3eaccf114ac3f3b5b51f57828a04996)
[metze@samba.org: improved for heimdal upstream]
Signed-off-by: Stefan Metzmacher <metze@samba.org>
[abartlet@samba.org: improved again for Heimdal based on feedback]
AES256 and AES128 are newer enctypes because they are officially
specified in RFC4120 and RFC8009, while enctypes not officially
specified since RFC4120 are considered older. This function differs from
older_enctype() in that it does not report unknown or non-existent
enctypes as being 'newer'.
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Instead of always advertising PADATA-ENCRYPTED-CHALLENGE, we only
advertise it if FAST is in use.
We also check configuration options to only advertise
PADATA-ENC-TIMESTAMP if it will be accepted based on whether FAST is
currently in use. This permits the non-RFC behaviour required to avoid
breaking earlier Heimdal clients.
This incorporates changes from Apple Heimdal-597.140.2.
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
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>
Import KDC FAST from Apple's Heimdal-597.121.1, adding support for:
- PA-ENC-CHALLENGE
- reply key strengthening
- FAST authentication in TGS
kuser: Apple sync (squash)
krb5_init_creds_store_config/krb5_init_creds_warn_user in kinit
We were losing and leaking the reason for which kdc_check_flags() was
rejecting any S4U requests, yielding incomplete error messages.
The issue is that kdc_check_flags() wants to check the client and server
principals in the input state structure, but doesn't know about
impersonated principal name, and so we want to pass it a state structure
that has the impersonated instead of the impersonator client name. This
is a bad design, but I'm ignoring that for now and just fixing this one
leak.
When generating an AS-REQ, the TGS signature was incorrectly generated using
the server key, which would fail to validate if the server was not also the
TGS. Fix this.
Patch from Isaac Bourkis <iboukris@gmail.com>.
The principal in the PAC_LOGON_NAME buffer is expected to match the client name
in the ticket. Previously we were setting this to the canonical client name,
which would have broken PAC validation if the client did not request name
canonicalization
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.
If GSS_Accept_sec_context() returns an error status and error token, ensure we
include the error token in the PA-GSS padata in the KRB-ERROR reply, rather
than bailing out early.
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.
RFC 6113 5.4.2 says that when hiding client names in the outer reply of a FAST
response, the wellknown anonymous principal MUST be used.
The previous implementation returned an empty client name and realm, which may
not be expected by some clients.
This is to match the Windows KDC behaviour, optionally.
Samba will use this mode, as Samba has tests that show
the difference and is keen for bug-for-bug/byte-for-byte
rather than strict RFC compliance where there is a
reasonable choice.
The Samba test (for reference) is
samba.tests.krb5.as_canonicalization_tests
The behaviour was changed in:
commit de1f37a6aa
Author: Luke Howard <lukeh@padl.com>
Date: Mon Jan 7 15:45:36 2019 +1100
kdc: omit default salt from PA-ETYPE-INFO[2]
If the salt for the AS-REP client key matches the default password salt for the
client principal in the AS-REQ, then it can be omitted from the PA-ETYPE-INFO,
PA-ETYPE-INFO2 (RFC4120) as the client will assume the default salt in its
absence.
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Windows does not check the password on an account that has been locked.
Heimdal does not implement locked_out, however the Samba hdb
backend does, and needs this checked before passwords (for bad
password lockout), not after in kdc_check_access().
Based on work to update Samba to current Heimdal by
Gary Lockyer <gary@catalyst.net.nz> and including cherry-pick of
Samba commit 580a705b83014e94556b9d5a8877406816e02190 which noted
that we need to return KRB5KDC_ERR_CLIENT_REVOKED to match Windows.
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
According to #788, Windows clients expect a revoked error to be returned if the
client or service is locked out, rather than a generic policy error. This
should not affect non-Windows paths as the locked_out HDB entry flag is
otherwise not used by Heimdal.
On Ubuntu 20.04 with gcc version 9.3.0 in a Samba compile
using -Wdiscarded-qualifiers and -Werror we get:
../../source4/heimdal/kdc/kerberos5.c:2516:21: warning: passing argument 2 of ‘_kdc_set_e_text’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
2516 | _kdc_set_e_text(r, "Client have no reply key");
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
../../source4/heimdal/kdc/kerberos5.c:428:42: note: expected ‘char *’ but argument is of type ‘const char *’
428 | _kdc_set_e_text(astgs_request_t r, char *fmt, ...)
| ~~~~~~^~~
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
- 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.
Status:
- And it works!
- We have an extensive test based on decoding a rich EK certficate.
This test exercises all of:
- decoding
- encoding with and without decoded open types
- copying of decoded values with decoded open types
- freeing of decoded values with decoded open types
Valgrind finds no memory errors.
- Added a manual page for the compiler.
- rfc2459.asn1 now has all three primary PKIX types that we care about
defined as in RFC5912, with IOS constraints and parameterization:
- `Extension` (embeds open type in an `OCTET STRING`)
- `OtherName` (embeds open type in an `ANY`-like type)
- `SingleAttribute` (embeds open type in an `ANY`-like type)
- `AttributeSet` (embeds open type in a `SET OF ANY`-like type)
All of these use OIDs as the open type type ID field, but integer
open type type ID fields are also supported (and needed, for
Kerberos).
That will cover every typed hole pattern in all our ASN.1 modules.
With this we'll be able to automatically and recursively decode
through all subject DN attributes even when the subject DN is a
directoryName SAN, and subjectDirectoryAttributes, and all
extensions, and all SANs, and all authorization-data elements, and
PA-data, and...
We're not really using `SingleAttribute` and `AttributeSet` yet
because various changes are needed in `lib/hx509` for that.
- `asn1_compile` builds and recognizes the subset of X.681/682/683 that
we need for, and now use in, rfc2459.asn1. It builds the necessary
AST, generates the correct C types, and generates templating for
object sets and open types!
- See READMEs for details.
- Codegen backend not tested; I won't make it implement automatic open
type handling, but it should at least not crash by substituting
`heim_any` for open types not embedded in `OCTET STRING`.
- We're _really_ starting to have problems with the ITU-T ASN.1
grammar and our version of it...
Type names have to start with upper-case, value names with
lower-case, but it's not enough to disambiguate.
The fact the we've allowed value and type names to violate their
respective start-with case rules is causing us trouble now that we're
adding grammar from X.681/682/683, and we're going to have to undo
that.
In preparation for that I'm capitalizing the `heim_any` and
`heim_any_set` types, and doing some additional cleanup, which
requires changes to other parts of Heimdal (all in this same commit
for now).
Problems we have because of this:
- We cannot IMPORT values into modules because we have no idea if a
symbol being imported refers to a value or a type because the only
clue we would have is the symbol's name, so we assume IMPORTed
symbols are for types.
This means we can't import OIDs, for example, which is super
annoying.
One thing we might be able to do here is mark imported symbols as
being of an undetermined-but-not-undefined type, then coerce the
symbol's type the first time it's used in a context where its type
is inferred as type, value, object, object set, or class. (Though
since we don't generate C symbols for objects or classes, we won't
be able to import them, especially since we need to know them at
compile time and cannot defer their handling to link- or
run-time.)
- The `NULL` type name, and the `NULL` value name now cause two
reduce/reduce conflicts via the `FieldSetting` production.
- Various shift/reduce conflicts involving `NULL` values in
non-top-level contexts (in constraints, for example).
- Currently I have a bug where to disambiguate the grammar I have a
CLASS_IDENTIFIER token that is all caps, while TYPE_IDENTIFIER must
start with a capital but not be all caps, but this breaks Kerberos
since all its types are all capitalized -- oof!
To fix this I made it so class names have to be all caps and
start with an underscore (ick).
TBD:
- Check all the XXX comments and address them
- Apply this treatment to Kerberos! Automatic handling of authz-data
sounds useful :)
- Apply this treatment to PKCS#10 (CSRs) and other ASN.1 modules too.
- Replace various bits of code in `lib/hx509/` with uses of this
feature.
- Add JER.
- Enhance `hxtool` and `asn1_print`.
Getting there!
The new [hdb] new_service_key_delay parameter should not apply to
principal entries when used as clients. Otherwise new passwords would
not take effect immediately, and that would be very confusing.
