Samba 4.19 Features added/changed

Samba 4.19 is Current Stable Release.

Samba 4.19.2

Release Notes for Samba 4.19.2

October 16, 2023

Changes since 4.19.1

• Jeremy Allison <jra@samba.org>

• BUG 15423: Use-after-free in aio_del_req_from_fsp during smbd shutdown after failed IPC FSCTL_PIPE_TRANSCEIVE.
• BUG 15426: clidfs.c do_connect() missing a "return" after a cli_shutdown() call.

• Ralph Boehme <slow@samba.org>

• BUG 15463: macOS mdfind returns only 50 results.

• Volker Lendecke <vl@samba.org>

• BUG 15481: GETREALFILENAME_CACHE can modify incoming new filename with previous cache entry value.

• Stefan Metzmacher <metze@samba.org>

• BUG 15464: libnss_winbind causes memory corruption since samba-4.18, impacts sendmail, zabbix, potentially more.

• Martin Schwenke <mschwenke@ddn.com>

• BUG 15479: ctdbd: setproctitle not initialized messages flooding logs.

• Joseph Sutton <josephsutton@catalyst.net.nz>

• BUG 15491: CVE-2023-5568 Heap buffer overflow with freshness tokens in the Heimdal KDC in Samba 4.19
• BUG 15477: The heimdal KDC doesn't detect s4u2self correctly when fast is in use.

Release Notes Samba 4.19.2

Samba 4.19.1

Release Notes for Samba 4.19.1

October 10, 2023

This is a security release in order to address the following defects:

• CVE-2023-3961:

Unsanitized pipe names allow SMB clients to connect as root to existing unix domain sockets on the file system.

• CVE-2023-4091:

SMB client can truncate files to 0 bytes by opening files with OVERWRITE disposition when using the acl_xattr Samba VFS module with the smb.conf setting "acl_xattr:ignore system acls = yes"

• CVE-2023-4154:

An RODC and a user with the GET_CHANGES right can view all attributes, including secrets and passwords. Additionally, the access check fails open on error conditions.

• CVE-2023-42669:

Calls to the rpcecho server on the AD DC can request that the server block for a user-defined amount of time, denying service.

• CVE-2023-42670:

Samba can be made to start multiple incompatible RPC listeners, disrupting service on the AD DC.

Changes since 4.19.0

• Jeremy Allison <jra@samba.org>

• BUG 15422: CVE-2023-3961.

• Andrew Bartlett <abartlet@samba.org>

• BUG 15424: CVE-2023-4154.
• BUG 15473: CVE-2023-42670.
• BUG 15474: CVE-2023-42669.

• Ralph Boehme <slow@samba.org>

• BUG 15439: CVE-2023-4091.

Release Notes Samba 4.19.1

Samba 4.19.0

Release Announcements

Release Notes for 4.19.0

September 04, 2023

This is the first stable release of the Samba 4.19 release series. Please read the release notes carefully before upgrading.

NEW FEATURES/CHANGES

Migrated smbget to use common command line parser

The smbget utility implemented its own command line parsing logic. After discovering an issue we decided to migrate it to use the common command line parser. This has some advantages as you get all the feature it provides like Kerberos authentication. The downside is that breaks the options interface. The support for smbgetrc has been removed. You can use an authentication file if needed, this is documented in the manpage.

Please check the smbget manpage or --help output.

gpupdate changes

The libgpo.get_gpo_list function has been deprecated in favor of an implementation written in python. The new function can be imported via `import samba.gp`. The python implementation connects to Active Directory using the SamDB module, instead of ADS (which is what libgpo uses).

Improved winbind logging and a new tool for parsing the winbind logs

Winbind logs (if smb.conf 'winbind debug traceid = yes' is set) contain new trace header fields 'traceid' and 'depth'. Field 'traceid' allows to track the trace records belonging to the same request. Field 'depth' allows to track the request nesting level. A new tool samba-log-parser is added for better log parsing.

AD database prepared to FL 2016 standards for new domains

While Samba still provides only Functional Level 2008R2 by default, Samba as an AD DC will now, in provision ensure that the blank database is already prepared for Functional Level 2016, with AD Schema 2019.

This preparation is of the default objects in the database, adding containers for Authentication Policies, Authentication Silos and AD claims in particular. These DB objects must be updated to allow operation of the new features found in higher functional levels.

Kerberos Claims, Authentication Silos and NTLM authentication policies

An initial, partial implementation of Active Directory FunctionalLevel 2012, 2012R2 and 2016 is available in this release.

In particular Samba will issue Active Directory "Claims" in the PAC, for member servers that support these, and honour in-directoryconfiguration for Authentication Policies and Authentication Silos.

The primary limitation is that while Samba can read and write claims in the directory, and populate the PAC, Samba does not yet use them for access control decisions.

While we continue to develop these features, existing domains can test the feature by selecting the functional level in provision or raising the DC functional level by setting

ad dc functional level = 2016

in the smb.conf

The smb.conf file on each DC must have 'ad dc functional level = 2016' set to have the partially complete feature available. This will also, at first startup, update the server's own AD entry with the configured functional level.

For new domains, add these parameters to 'samba-tool provision'

--option="ad dc functional level = 2016" --function-level=2016

The second option, setting the overall domain functional level indicates that all DCs should be at this functional level.

To raise the domain functional level of an existing domain, after updating the smb.conf and restarting Samba run

samba-tool domain schemaupgrade --schema=2019
samba-tool domain functionalprep --function-level=2016
samba-tool domain level raise --domain-level=2016 --forest-level=2016

Improved KDC Auditing

As part of the auditing required to allow successful deployment of Authentication Policies and Authentication Silos, our KDC now provides Samba-style JSON audit logging of all issued Kerberos tickets, including if they would fail a policy that is not yet enforced. Additionally most failures are audited, (after the initial pre-validation of the request).

Kerberos Armoring (FAST) Support for Windows clients

In domains where the domain controller functional level is set, as above, to 2012, 2012_R2 or 2016, Windows clients will, if configured via GPO, use FAST to protect user passwords between (in particular) a workstation and the KDC on the AD DC. This is a significant security improvement, as weak passwords in an AS-REQ are no longer available for offline attack.

Claims compression in the AD PAC

Samba as an AD DC will compress "AD claims" using the same compression algorithm as Microsoft Windows.

Resource SID compression in the AD PAC

Samba as an AD DC will now correctly populate the various PAC group membership buffers, splitting global and local groups correctly.

Additionally, Samba marshals Resource SIDs, being local groups in the member server's own domain, to only consume a header and 4 bytes per group in the PAC, not a full-length SID worth of space each. This is known as "Resource SID compression".

Resource Based Constrained Delegation (RBCD) support in both MIT and Heimdal

Samba AD DC built with MIT Kerberos (1.20 and later) has offered RBCD support since Samba 4.17. Samba 4.19 brings this feature to the default Heimdal KDC.

Samba 4.17 added to samba-tool delegation the 'add-principal' and 'del-principal' subcommands in order to manage RBCD, and the database changes made by these tools are now honoured by the Heimdal KDC once Samba is upgraded.

Likewise, now both MIT (1.20 and later) and Heimdal KDCs add the Asserted Identity [1] SID into the PAC for constrained delegation.

[1] https://docs.microsoft.com/en-us/windows-server/security/kerberos/kerberos-constrained-delegation-overview

New samba-tool support for silos, claims, sites and subnets.

• samba-tool can now list, show, add and manipulate Authentication Silos (silos) and Active Directory Authentication Claims (claims).
• samba-tool can now list and show Active Directory sites and subnets.

A new Object Relational Model (ORM) based architecture, similar to that used with Django, has been built to make adding new samba-tool subcommands simpler and more consistent, with JSON output available standard on these new commands.

Updated GnuTLS requirement / in-tree cryptography removal

Samba requires GnuTLS 3.6.13 and prefers GnuTLS 3.6.14 or later.

This has allowed Samba to remove all of our in-tree cryptography, except that found in our Heimdal import. Samba's runtime cryptography needs are now all provided by GnuTLS.

note: The GnuTLS vesion requirement is raised to 3.7.2 on systems without the Linux getrandom()

We also use Python's cryptography module for our testing.

The use of well known cryptography libraries makes Samba easier for end-users to validate and deploy, and for distributors to ship. This is the end of a very long journey for Samba.

Updated Heimdal import

Samba's Heimdal branch (known as lorikeet-heimdal) has been updated to the current pre-8.0 (master) tree from upstream Heimdal, ensuring that this vendored copy, included in our release remains as close as possible to the current upstream code.

Revocation support in Heimdal KDC for PKINIT certificates

Samba will now correctly honour the revocation of 'smart card' certificates used for PKINIT Kerberos authentication.

This list is reloaded each time the file changes, so no further action other than replacing the file is required.

The additional krb5.conf option is:

[kdc]
    pkinit_revoke = FILE:/path/to/crl.pem

Information on the "Smart Card login" feature as a whole is at:

Samba_AD_Smart_Card_Login

Protocol level testsuite for (Smart Card Logon) PKINIT

Previously Samba's PKINIT support in the KDC was tested by use of shell scripts around the client tools of MIT or Heimdal Kerberos. Samba's independently written python testsuite has been extended to validate KDC behaviour for PKINIT.

Require encrypted connection to modify unicodePwd on the AD DC

Setting the password on an AD account on should never be attempted over a plaintext or signed-only LDAP connection. If the unicodePwd (or userPassword) attribute is modified without encryption (as seen by Samba), the request will be rejected. This is to encourage the administrator to use an encrypted connection in the future.

NOTE WELL: If Samba is accessed via a TLS frontend or load balancer, the LDAP request will be regarded as plaintext.

Samba AD TLS Certificates can be reloaded

The TLS certificates used for Samba's AD DC LDAP server were previously only read on startup, and this meant that when then expired it was required to restart Samba, disrupting service to other users.

smbcontrol ldap_server reload-certs

This will now allow these certificates to be reloaded 'on the fly'

smb.conf changes

 Parameter Name                          Description     Default
 --------------                          -----------     -------
 winbind debug traceid                   Add traceid     No
 directory name cache size               Removed

CHANGES SINCE 4.19.0rc4

• MikeLiu <mikeliu@qnap.com>

• #15453: File doesn't show when user doesn't have permission if aio_pthread is loaded.

• Martin Schwenke <mschwenke@ddn.com>

• #15451: ctdb_killtcp fails to work with --enable-pcap and libpcap > 1.9.0.

CHANGES SINCE 4.19.0rc3

• Martin Schwenke <mschwenke@ddn.com>

• BUG #15460: Logging to stdout/stderr with DEBUG_SYSLOG_FORMAT_ALWAYS can log to syslog.

• Joseph Sutton <josephsutton@catalyst.net.nz>

• BUG #15458: 'samba-tool domain level raise' fails unless given a URL.

CHANGES SINCE 4.19.0rc2

• Jeremy Allison <jra@samba.org>

• BUG #15420: reply_sesssetup_and_X() can dereference uninitialized tmp pointer.
• BUG #15430: missing return in reply_exit_done().
• BUG #15432: TREE_CONNECT without SETUP causes smbd to use uninitialized pointer.

• Andrew Bartlett <abartlet@samba.org>

• BUG #15401: Avoid infinite loop in initial user sync with Azure AD Connect when synchronising a large Samba AD domain.
• BUG #15407: Samba replication logs show (null) DN.

• Stefan Metzmacher <metze@samba.org>

• BUG #15346: 2-3min delays at reconnect with smb2_validate_sequence_number: bad message_id 2.
• BUG #15446: DCERPC_PKT_CO_CANCEL and DCERPC_PKT_ORPHANED can't be parsed.

• Martin Schwenke <mschwenke@ddn.com>

• BUG #15438: CID 1539212 causes real issue when output contains only newlines.

• Joseph Sutton <josephsutton@catalyst.net.nz>

• BUG #15452: KDC encodes INT64 claims incorrectly.

• Jones Syue <jonessyue@qnap.com>

• BUG #15449: mdssvc: Do an early talloc_free() in _mdssvc_open().

CHANGES SINCE 4.19.0rc1

• Andrew Bartlett <abartlet@samba.org>

• BUG #9959: Windows client join fails if a second container CN=System exists somewhere.

• Noel Power <noel.power@suse.com>

• BUG #15435: regression DFS not working with widelinks = true.

• Arvid Requate <requate@univention.de>

• BUG #9959: Windows client join fails if a second container CN=System exists somewhere.

• Joseph Sutton <josephsutton@catalyst.net.nz>

• BUG #15443: Heimdal fails to build on 32-bit FreeBSD.

• Jones Syue <jonessyue@qnap.com>

• BUG #15441: samba-tool ntacl get segfault if aio_pthread appended.

KNOWN ISSUES

Release_Planning_for_Samba_4.19#Release_blocking_bugs

Release Notes Samba 4.19.0