Samba 4.3 Features added/changed

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Samba 4.3.11

Release Notes for Samba 4.3.11
July 07, 2016

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

  • CVE-2016-2119 (Client side SMB2/3 required signing can be downgraded)

Details

It's possible for an attacker to downgrade the required signing for an SMB2/3 client connection, by injecting the SMB2_SESSION_FLAG_IS_GUEST or SMB2_SESSION_FLAG_IS_NULL flags.

This means that the attacker can impersonate a server being connected to by Samba, and return malicious results.

The primary concern is with winbindd, as it uses DCERPC over SMB2 when talking to domain controllers as a member server, and trusted domains as a domain controller. These DCE/RPC connections were intended to protected by the combination of "client ipc signing" and "client ipc max protocol" in their effective default settings ("mandatory" and "SMB3_11").

Additionally, management tools like net, samba-tool and rpcclient use DCERPC over SMB2/3 connections.

By default, other tools in Samba are unprotected, but rarely they are configured to use smb signing, via the "client signing" parameter (the default is "if_required"). Even more rarely the "client max protocol" is set to SMB2, rather than the NT1 default.

If both these conditions are met, then this issue would also apply to these other tools, including command line tools like smbcacls, smbcquota, smbclient, smbget and applications using libsmbclient.

Changes since 4.3.11:

  • Stefan Metzmacher <metze@samba.org>
https://www.samba.org/samba/history/samba-4.3.11.html


Samba 4.3.10

Release Notes for Samba 4.3.10
June 15, 2016

This is the latest stable release of Samba 4.3.

Changes since 4.3.9:

  • Jeremy Allison <jra@samba.org>
  • Christian Ambach <ambi@samba.org>
  • BUG #10796: s3:rpcclient: Make '--pw-nt-hash' option work.
  • BUG #11354: s3:libsmb/clifile: Use correct value for MaxParameterCount for setting EAs.
  • BUG #11438: s3:smbd/service disable case-sensitivity for SMB2/3 connections.
  • Ralph Boehme <slow@samba.org>
  • BUG #1703: s3:libnet:libnet_join: Add netbios aliases as SPNs.
  • BUG #11721: vfs_fruit: Add an option that allows disabling POSIX rename behaviour.
  • Alexander Bokovoy <ab@samba.org>
  • Jérémie Courrèges-Anglas <jca@wxcvbn.org>
  • BUG #11864: Provide fallback code for non-portable clearenv(3).
  • Günther Deschner <gd@samba.org>
  • BUG #11864: s3:client:smbspool_krb5_wrapper: fix the non clearenv build.
  • Robin McCorkell <robin@mccorkell.me.uk>
  • BUG #11276: Correctly set cli->raw_status for libsmbclient in SMB2 code.
  • Stefan Metzmacher <metze@samba.org>
  • BUG #11910: s3:smbd: Fix anonymous authentication if signing is mandatory.
  • BUG #11912: libcli/auth: Let msrpc_parse() return talloc'ed empty strings.
  • BUG #11914: s3:ntlm_auth: Make ntlm_auth_generate_session_info() more complete.
  • BUG #11927: s3:rpcclient: Make use of SMB_SIGNING_IPC_DEFAULT.
  • Luca Olivetti <luca@wetron.es>
  • BUG #11530: pdb: Fix segfault in pdb_ldap for missing gecos.
  • Rowland Penny <rpenny@samba.org>
  • BUG #11613: samba-tool: Allow 'samba-tool fsmo' to cope with empty or missing fsmo roles.
  • Anoop C S <anoopcs@redhat.com>
  • BUG #11907: packaging: Set default limit for core file size in service files.
  • Andreas Schneider <asn@samba.org>
  • BUG #11922: s3-net: Convert the key_name to UTF8 during migration.
  • BUG #11935: s3-smbspool: Log to stderr.
  • Uri Simchoni <uri@samba.org>
  • BUG #11900: heimdal: Encode/decode kvno as signed integer.
  • BUG #11931: s3-quotas: Fix sysquotas_4B quota fetching for BSD.
  • Raghavendra Talur <rtalur@redhat.com>
  • BUG #11907: init: Set core file size to unlimited by default.
  • Hemanth Thummala <hemanth.thummala@nutanix.com>
  • BUG #11934: Fix memory leak in share mode locking.
  • Volker Lendecke <vl@samba.org>
  • Lorinczy Zsigmond <lzsiga@freemail.c3.hu>
  • BUG #11947: lib: replace: snprintf - Fix length calculation for hex/octal 64-bit values.
https://www.samba.org/samba/history/samba-4.3.10.html

Samba 4.3.9

Release Notes for Samba 4.3.9
May 2, 2016


This is the latest stable release of Samba 4.3.

This release fixes some regressions introduced by the last security fixes. Please see bug https://bugzilla.samba.org/show_bug.cgi?id=11849 for a list of bugs addressing these regressions and more information.


Changes since 4.3.8:

  • Jeremy Allison <jra@samba.org>
  • BUG #11742: lib: tevent: Fix memory leak when old signal action restored.
  • BUG #11771: lib: tevent: Fix memory leak when old signal action restored.
  • BUG #11822: s3: libsmb: Fix error where short name length was read as 2 bytes, should be 1.
  • Andrew Bartlett <abartlet@samba.org>
  • BUG #11780: smbd: Only check dev/inode in open_directory, not the full stat().
  • BUG #11789: pydsdb: Fix returning of ldb.MessageElement.
Berend De Schouwer <berend.de.schouwer@gmail.com>
  • BUG #11643: docs: Add example for domain logins to smbspool man page.
  • Günther Deschner <gd@samba.org>
  • BUG #11789: libsmb/pysmb: Add pytalloc-util dependency to fix the build.
  • Alberto Maria Fiaschi <alberto.fiaschi@estar.toscana.it>
  • BUG #8093: access based share enum: Handle permission set in configuration files.
  • Volker Lendecke <vl@samba.org>
  • Stefan Metzmacher <metze@samba.org>
  • BUG #11622: libcli/smb: Make sure we have a body size of 0x31 before dereferencing an ioctl response.
  • BUG #11623: libcli/smb: Fix BUFFER_OVERFLOW handling in tstream_smbXcli_np.
  • BUG #11755: s3:libads: Setup the msDS-SupportedEncryptionTypes attribute on ldap_add.
  • BUG #11771: tevent: Version 0.9.28. Fix memory leak when old signal action restored.
  • BUG #11782: s3:winbindd: Don't include two '\0' at the end of the domain list.
  • BUG #11789: s3:wscript: pylibsmb depends on pycredentials.
  • BUG #11841: Fix NT_STATUS_ACCESS_DENIED when accessing Windows public share.
  • BUG #11847: Only validate MIC if "map to guest" is not being used.
  • BUG #11849: auth/ntlmssp: Add ntlmssp_{client,server}:force_old_spnego option for testing.
  • BUG #11850: NetAPP SMB servers don't negotiate NTLMSSP_SIGN.
  • BUG #11858: Allow anonymous smb connections.
  • BUG #11870: Fix ads_sasl_spnego_gensec_bind(KRB5).
  • BUG #11872: Fix 'wbinfo -u' and 'net ads search'.
  • Noel Power <noel.power@suse.com>
  • BUG #11738: libcli: Fix debug message, print sid string for new_ace trustee.
  • Garming Sam <garming@catalyst.net.nz>
  • BUG #11789: build: Mark explicit dependencies on pytalloc-util.
  • Partha Sarathi <partha@exablox.com>
  • BUG #11819: Fix the smb2_setinfo to handle FS info types and FSQUOTA infolevel.
  • Jorge Schrauwen <sjorge@blackdot.be>
  • BUG #11816: configure: Don't check for inotify on illumos.
  • Uri Simchoni <uri@samba.org>
  • BUG #11691: winbindd: Return trust parameters when listing trusts.
  • BUG #11753: smbd: Ignore SVHDX create context.
  • BUG #11763: passdb: Add linefeed to debug message.
  • BUG #11788: build: Fix disk-free quota support on Solaris 10.
  • BUG #11798: build: Fix build when '--without-quota' specified.
  • BUG #11806: vfs_acl_common: Avoid setting POSIX ACLs if "ignore system acls" is set.
  • BUG #11852: libads: Record session expiry for spnego sasl binds.
  • Hemanth Thummala <hemanth.thummala@nutanix.com>
  • BUG #11740: Real memory leak(buildup) issue in loadparm.
  • BUG #11840: Mask general purpose signals for notifyd.
https://www.samba.org/samba/history/samba-4.3.9.html

Samba 4.3.8

Release Notes for Samba 4.3.8
April 12, 2016

This is a security release containing one additional regression fix for the security release 4.2.10.

This fixes a regression that prevents things like 'net ads join' from working against a Windows 2003 domain.

Changes since 4.3.7:

  • Stefan Metzmacher <metze@samba.org>
  • BUG #11804 - prerequisite backports for the security release on April 12th, 2016

Samba 4.3.7

Release Notes for Samba 4.3.7
April 12, 2016

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

The number of changes are rather huge for a security release, compared to typical security releases.

Given the number of problems and the fact that they are all related to man in the middle attacks we decided to fix them all at once instead of splitting them.

In order to prevent the man in the middle attacks it was required to change the (default) behavior for some protocols. Please see the "New smb.conf options" and "Behavior changes" sections below.

Details

CVE-2015-5370

Versions of Samba from 3.6.0 to 4.4.0 inclusive are vulnerable to denial of service attacks (crashes and high cpu consumption) in the DCE-RPC client and server implementations. In addition, errors in validation of the DCE-RPC packets can lead to a downgrade of a secure connection to an insecure one.

While we think it is unlikely, there's a nonzero chance for a remote code execution attack against the client components, which are used by smbd, winbindd and tools like net, rpcclient and others. This may gain root access to the attacker.

The above applies all possible server roles Samba can operate in.

Note that versions before 3.6.0 had completely different marshalling functions for the generic DCE-RPC layer. It's quite possible that that code has similar problems!

The downgrade of a secure connection to an insecure one may allow an attacker to take control of Active Directory object handles created on a connection created from an Administrator account and re-use them on the now non-privileged connection, compromising the security of the Samba AD-DC.

CVE-2016-2110:

There are several man in the middle attacks possible with NTLMSSP authentication.

E.g. NTLMSSP_NEGOTIATE_SIGN and NTLMSSP_NEGOTIATE_SEAL can be cleared by a man in the middle.

This was by protocol design in earlier Windows versions.

Windows Server 2003 RTM and Vista RTM introduced a way to protect against the trivial downgrade.

See MsvAvFlags and flag 0x00000002 in

  https://msdn.microsoft.com/en-us/library/cc236646.aspx

This new feature also implies support for a mechlistMIC when used within SPNEGO, which may prevent downgrades from other SPNEGO mechs, e.g. Kerberos, if sign or seal is finally negotiated.

The Samba implementation doesn't enforce the existence of required flags, which were requested by the application layer, e.g. LDAP or SMB1 encryption (via the unix extensions). As a result a man in the middle can take over the connection. It is also possible to misguide client and/or server to send unencrypted traffic even if encryption was explicitly requested.

LDAP (with NTLMSSP authentication) is used as a client by various admin tools of the Samba project, e.g. "net", "samba-tool", "ldbsearch", "ldbedit", ...

As an active directory member server LDAP is also used by the winbindd service when connecting to domain controllers.

Samba also offers an LDAP server when running as active directory domain controller.

The NTLMSSP authentication used by the SMB1 encryption is protected by smb signing, see CVE-2015-5296.

CVE-2016-2111:

It's basically the same as CVE-2015-0005 for Windows:

The NETLOGON service in Microsoft Windows Server 2003 SP2, Windows Server 2008 SP2 and R2 SP1, and Windows Server 2012 Gold and R2, when a Domain Controller is configured, allows remote attackers to spoof the computer name of a secure channel's endpoint, and obtain sensitive session information, by running a crafted application and leveraging the ability to sniff network traffic, aka "NETLOGON Spoofing Vulnerability".

The vulnerability in Samba is worse as it doesn't require credentials of a computer account in the domain.

This only applies to Samba running as classic primary domain controller, classic backup domain controller or active directory domain controller.

The security patches introduce a new option called "raw NTLMv2 auth" ("yes" or "no") for the [global] section in smb.conf. Samba (the smbd process) will reject client using raw NTLMv2 without using NTLMSSP.

Note that this option also applies to Samba running as standalone server and member server.

You should also consider using "lanman auth = no" (which is already the default) and "ntlm auth = no". Have a look at the smb.conf manpage for further details, as they might impact compatibility with older clients. These also apply for all server roles.

CVE-2016-2112:

Samba uses various LDAP client libraries, a builtin one and/or the system ldap libraries (typically openldap).

As active directory domain controller Samba also provides an LDAP server.

Samba takes care of doing SASL (GSS-SPNEGO) authentication with Kerberos or NTLMSSP for LDAP connections, including possible integrity (sign) and privacy (seal) protection.

Samba has support for an option called "client ldap sasl wrapping" since version 3.2.0. Its default value has changed from "plain" to "sign" with version 4.2.0.

Tools using the builtin LDAP client library do not obey the "client ldap sasl wrapping" option. This applies to tools like: "samba-tool", "ldbsearch", "ldbedit" and more. Some of them have command line options like "--sign" and "--encrypt". With the security update they will also obey the "client ldap sasl wrapping" option as default.

In all cases, even if explicitly request via "client ldap sasl wrapping", "--sign" or "--encrypt", the protection can be downgraded by a man in the middle.

The LDAP server doesn't have an option to enforce strong authentication yet. The security patches will introduce a new option called "ldap server require strong auth", possible values are "no", "allow_sasl_over_tls" and "yes".

As the default behavior was as "no" before, you may have to explicitly change this option until all clients have been adjusted to handle LDAP_STRONG_AUTH_REQUIRED errors. Windows clients and Samba member servers already use integrity protection.

CVE-2016-2113:

Samba has support for TLS/SSL for some protocols: ldap and http, but currently certificates are not validated at all. While we have a "tls cafile" option, the configured certificate is not used to validate the server certificate.

This applies to ldaps:// connections triggered by tools like: "ldbsearch", "ldbedit" and more. Note that it only applies to the ldb tools when they are built as part of Samba or with Samba extensions installed, which means the Samba builtin LDAP client library is used.

It also applies to dcerpc client connections using ncacn_http (with https://), which are only used by the openchange project. Support for ncacn_http was introduced in version 4.2.0.

The security patches will introduce a new option called "tls verify peer". Possible values are "no_check", "ca_only", "ca_and_name_if_available", "ca_and_name" and "as_strict_as_possible".

If you use the self-signed certificates which are auto-generated by Samba, you won't have a crl file and need to explicitly set "tls verify peer = ca_and_name".

CVE-2016-2114

Due to a regression introduced in Samba 4.0.0, an explicit "server signing = mandatory" in the [global] section of the smb.conf was not enforced for clients using the SMB1 protocol.

As a result it does not enforce smb signing and allows man in the middle attacks.

This problem applies to all possible server roles: standalone server, member server, classic primary domain controller, classic backup domain controller and active directory domain controller.

In addition, when Samba is configured with "server role = active directory domain controller" the effective default for the "server signing" option should be "mandatory".

During the early development of Samba 4 we had a new experimental file server located under source4/smb_server. But before the final 4.0.0 release we switched back to the file server under source3/smbd.

But the logic for the correct default of "server signing" was not ported correctly ported.

Note that the default for server roles other than active directory domain controller, is "off" because of performance reasons.

CVE-2016-2115:

Samba has an option called "client signing", this is turned off by default for performance reasons on file transfers.

This option is also used when using DCERPC with ncacn_np.

In order to get integrity protection for ipc related communication by default the "client ipc signing" option is introduced. The effective default for this new option is "mandatory".

In order to be compatible with more SMB server implementations, the following additional options are introduced:

  • "client ipc min protocol" ("NT1" by default) and
  • "client ipc max protocol" (the highest support SMB2/3 dialect by default).
These options overwrite the "client min protocol" and "client max protocol" options, because the default for "client max protocol" is still "NT1". The reason for this is the fact that all SMB2/3 support SMB signing, while there are still SMB1 implementations which don't offer SMB signing by default (this includes Samba versions before 4.0.0).

Note that winbindd (in versions 4.2.0 and higher) enforces SMB signing against active directory domain controllers despite of the "client signing" and "client ipc signing" options.

CVE-2016-2118 (a.k.a. BADLOCK):

The Security Account Manager Remote Protocol [MS-SAMR] and the Local Security Authority (Domain Policy) Remote Protocol [MS-LSAD] are both vulnerable to man in the middle attacks. Both are application level protocols based on the generic DCE 1.1 Remote Procedure Call (DCERPC) protocol.

These protocols are typically available on all Windows installations as well as every Samba server. They are used to maintain the Security Account Manager Database. This applies to all roles, e.g. standalone, domain member, domain controller.

Any authenticated DCERPC connection a client initiates against a server can be used by a man in the middle to impersonate the authenticated user against the SAMR or LSAD service on the server.

The client chosen application protocol, auth type (e.g. Kerberos or NTLMSSP) and auth level (NONE, CONNECT, PKT_INTEGRITY, PKT_PRIVACY) do not matter in this case. A man in the middle can change auth level to CONNECT (which means authentication without message protection) and take over the connection.

As a result, a man in the middle is able to get read/write access to the Security Account Manager Database, which reveals all password sand any other potential sensitive information.

Samba running as an active directory domain controller is additionally missing checks to enforce PKT_PRIVACY for the Directory Replication Service Remote Protocol [MS-DRSR] (drsuapi) and the BackupKey Remote Protocol [MS-BKRP] (backupkey). The Domain Name Service Server Management Protocol [MS-DNSP] (dnsserver) is not enforcing at least PKT_INTEGRITY.

New smb.conf options

allow dcerpc auth level connect (G)

This option controls whether DCERPC services are allowed to be used with DCERPC_AUTH_LEVEL_CONNECT, which provides authentication, but no per message integrity nor privacy protection.

Some interfaces like samr, lsarpc and netlogon have a hard-coded default of no and epmapper, mgmt and rpcecho have a hard-coded default of yes.

The behavior can be overwritten per interface name (e.g. lsarpc, netlogon, samr, srvsvc, winreg, wkssvc ...) by using 'allow dcerpc auth level connect:interface = yes' as option.

This option yields precedence to the implementation specific restrictions. E.g. the drsuapi and backupkey protocols require DCERPC_AUTH_LEVEL_PRIVACY. The dnsserver protocol requires DCERPC_AUTH_LEVEL_INTEGRITY.

   Default: allow dcerpc auth level connect = no
   Example: allow dcerpc auth level connect = yes

client ipc signing (G)

This controls whether the client is allowed or required to use SMB signing for IPC$ connections as DCERPC transport. Possible values are auto, mandatory and disabled.

When set to mandatory or default, SMB signing is required. When set to auto, SMB signing is offered, but not enforced and if set to disabled, SMB signing is not offered either.

Connections from winbindd to Active Directory Domain Controllers always enforce signing.

   Default: client ipc signing = default

client ipc max protocol (G)

The value of the parameter (a string) is the highest protocol level that will be supported for IPC$ connections as DCERPC transport.

Normally this option should not be set as the automatic negotiation phase in the SMB protocol takes care of choosing the appropriate protocol.

The value default refers to the latest supported protocol, currently SMB3_11.

See client max protocol for a full list of available protocols. The values CORE, COREPLUS, LANMAN1, LANMAN2 are silently upgraded to NT1.

   Default: client ipc max protocol = default
   Example: client ipc max protocol = SMB2_10

client ipc min protocol (G)

This setting controls the minimum protocol version that the will be attempted to use for IPC$ connections as DCERPC transport.

Normally this option should not be set as the automatic negotiation phase in the SMB protocol takes care of choosing the appropriate protocol.

The value default refers to the higher value of NT1 and the effective value of "client min protocol".

See client max protocol for a full list of available protocols. The values CORE, COREPLUS, LANMAN1, LANMAN2 are silently upgraded to NT1.

   Default: client ipc min protocol = default
   Example: client ipc min protocol = SMB3_11

ldap server require strong auth (G)

The ldap server require strong auth defines whether the ldap server requires ldap traffic to be signed or signed and encrypted (sealed). Possible values are no, allow_sasl_over_tls and yes.

A value of no allows simple and sasl binds over all transports.

A value of allow_sasl_over_tls allows simple and sasl binds (without sign or seal) over TLS encrypted connections. Unencrypted connections only allow sasl binds with sign or seal.

A value of yes allows only simple binds over TLS encrypted connections. Unencrypted connections only allow sasl binds with sign or seal.

   Default: ldap server require strong auth = yes

raw NTLMv2 auth (G)

This parameter determines whether or not smbd(8) will allow SMB1 clients without extended security (without SPNEGO) to use NTLMv2 authentication.

If this option, lanman auth and ntlm auth are all disabled, then only clients with SPNEGO support will be permitted. That means NTLMv2 is only supported within NTLMSSP.

   Default: raw NTLMv2 auth = no

tls verify peer (G)

This controls if and how strict the client will verify the peer's certificate and name. Possible values are (in increasing order): no_check, ca_only, ca_and_name_if_available, ca_and_name and as_strict_as_possible.

When set to no_check the certificate is not verified at all, which allows trivial man in the middle attacks.

When set to ca_only the certificate is verified to be signed from a ca specified in the "tls ca file" option. Setting "tls ca file" to a valid file is required. The certificate lifetime is also verified. If the "tls crl file" option is configured, the certificate is also verified against the ca crl.

When set to ca_and_name_if_available all checks from ca_only are performed. In addition, the peer hostname is verified against the certificate's name, if it is provided by the application layer and not given as an ip address string.

When set to ca_and_name all checks from ca_and_name_if_available are performed. In addition the peer hostname needs to be provided and even an ip address is checked against the certificate's name.

When set to as_strict_as_possible all checks from ca_and_name are performed. In addition the "tls crl file" needs to be configured. Future versions of Samba may implement additional checks.

   Default: tls verify peer = as_strict_as_possible

tls priority (G) (backported from Samba 4.3 to Samba 4.2)

This option can be set to a string describing the TLS protocols to be supported in the parts of Samba that use GnuTLS, specifically the AD DC.

The default turns off SSLv3, as this protocol is no longer considered secure after CVE-2014-3566 (otherwise known as POODLE) impacted SSLv3 use in HTTPS applications.

The valid options are described in the GNUTLS Priority-Strings documentation at http://gnutls.org/manual/html_node/Priority-Strings.html

   Default: tls priority = NORMAL:-VERS-SSL3.0

Behavior changes

  • The default auth level for authenticated binds has changed from DCERPC_AUTH_LEVEL_CONNECT to DCERPC_AUTH_LEVEL_INTEGRITY. That means ncacn_ip_tcp:server is now implicitly the same as ncacn_ip_tcp:server[sign] and offers a similar protection as ncacn_np:server, which relies on smb signing.
  • The following constraints are applied to SMB1 connections:
    • "client lanman auth = yes" is now consistently required for authenticated connections using the SMB1 LANMAN2 dialect.
    • "client ntlmv2 auth = yes" and "client use spnego = yes" (both the default values), require extended security (SPNEGO) support from the server. That means NTLMv2 is only used within NTLMSSP.
  • Tools like "samba-tool", "ldbsearch", "ldbedit" and more obey the default of "client ldap sasl wrapping = sign". Even with "client ldap sasl wrapping = plain" they will automatically upgrade to "sign" when getting LDAP_STRONG_AUTH_REQUIRED from the LDAP server.

Changes since 4.3.6:

  • Jeremy Allison <jra@samba.org>
  • Christian Ambach <ambi@samba.org>
  • BUG #11804 - prerequisite backports for the security release on April 12th, 2016.
  • Ralph Boehme <slow@samba.org>
  • Günther Deschner <gd@samba.org>
  • Björn Jacke <bj@sernet.de>
  • BUG #11804 - prerequisite backports for the security release on April 12th, 2016.

o Volker Lendecke <vl@samba.org>

  • BUG #11804 - prerequisite backports for the security release on April 12th, 2016.

o Stefan Metzmacher <metze@samba.org>

  • Richard Sharpe <rsharpe@samba.org>
  • BUG #11804 - prerequisite backports for the security release on April 12th, 2016.


Samba 4.3.6

Release Notes for Samba 4.3.6 March 8, 2016

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

Details

All versions of Samba from 3.2.0 to 4.4.0rc3 inclusive are vulnerable to a malicious client overwriting the ownership of ACLs using symlinks.
An authenticated malicious client can use SMB1 UNIX extensions to create a symlink to a file or directory, and then use non-UNIX SMB1 calls to overwrite the contents of the ACL on the file or directory linked to.
All versions of Samba from 4.0.0 to 4.4.0rc3 inclusive, when deployed as an AD DC and choose to run the internal DNS server, are vulnerable to an out-of-bounds read issue during DNS TXT record handling caused by users with permission to modify DNS records.
A malicious client can upload a specially constructed DNS TXT record, resulting in a remote denial-of-service attack. As long as the affected TXT record remains undisturbed in the Samba database, a targeted DNS query may continue to trigger this exploit.
While unlikely, the out-of-bounds read may bypass safety checks and allow leakage of memory from the server in the form of a DNS TXT reply.
By default only authenticated accounts can upload DNS records, as "allow dns updates = secure only" is the default. Any other value would allow anonymous clients to trigger this bug, which is a much higher risk.


Changes since 4.3.5:

  • Jeremy Allison <jra@samba.org>
  • Garming Sam <garming@catalyst.net.nz>
  • Stefan Metzmacher <metze@samba.org>
https://www.samba.org/samba/history/samba-4.3.6.html

Samba 4.3.5

Release Notes for Samba 4.3.5
February 23, 2016

This is the latest stable release of Samba 4.3.

Changes since 4.3.4:

  • Jeremy Allison <jra@samba.org>
  • BUG #10489: s3: smbd: posix_acls: Fix check for setting u:g:o entry on a filesystem with no ACL support.
  • BUG #11703: s3: smbd: Fix timestamp rounding inside SMB2 create.
  • Christian Ambach <ambi@samba.org>
  • BUG #6482: s3:utils/smbget: Fix recursive download.
  • BUG #11400: s3:smbd/oplock: Obey kernel oplock setting when releasing oplocks.
  • Alexander Bokovoy <ab@samba.org>
  • BUG #11693: s3-parm: Clean up defaults when removing global parameters.
  • Ralph Boehme <slow@samba.org>
  • BUG #11684: s3:smbd: Ignore initial allocation size for directory creation.
  • BUG #11714: lib/tsocket: Work around sockets not supporting FIONREAD.
  • Amitay Isaacs <amitay@gmail.com>
  • BUG #11705: ctdb: Remove error messages after kernel security update (CVE-2015-8543).
  • Volker Lendecke <vl@samba.org>
  • BUG #11732: param: Fix str_list_v3 to accept ";" again.
  • Stefan Metzmacher <metze@samba.org>
  • BUG #11699: Use M2Crypto.RC4.RC4 on platforms without Crypto.Cipher.ARC4.
  • Jose A. Rivera <jarrpa@samba.org>
  • BUG #11727: s3:smbd:open: Skip redundant call to file_set_dosmode when creating a new file.
  • Christof Schmitt <cs@samba.org>
  • BUG #11670: winbindd: Handle expired sessions correctly.
  • Andreas Schneider <asn@samba.org>
  • BUG #11690: s3-client: Add a KRB5 wrapper for smbspool.
  • Uri Simchoni <uri@samba.org>
  • BUG #11580: vfs_shadow_copy2: Fix case where snapshots are outside the share.
  • BUG #11662: smbclient: Query disk usage relative to current directory.
  • BUG #11681: smbd: Show correct disk size for different quota and dfree block sizes.
  • BUG #11682: smbcacls: Fix uninitialized variable.
  • Martin Schwenke <martin@meltin.net>
  • BUG #11719: ctdb-scripts: Drop use of "smbcontrol winbindd ip-dropped ...".
  • Hemanth Thummala <hemanth.thummala@nutanix.com>
https://www.samba.org/samba/history/samba-4.3.5.html

Samba 4.3.4

Release Notes for Samba 4.3.4
January 12, 2016

This is the latest stable release of Samba 4.3.

Changes since 4.3.3

  • Michael Adam <obnox@samba.org>
  • BUG #11619: doc: Fix a typo in the smb.conf manpage, explanation of idmap config.
  • BUG #11647: s3:smbd: Fix a corner case of the symlink verification.
  • Jeremy Allison <jra@samba.org>
  • BUG #11624: s3: libsmb: Correctly initialize the list head when keeping a list of primary followed by DFS connections.
  • BUG #11625: Reduce the memory footprint of empty string options.
  • Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
  • BUG #11659: Update lastLogon and lastLogonTimestamp.
  • Ralph Boehme <slow@samba.org>
  • BUG #11065: vfs_fruit: Enable POSIX directory rename semantics.
  • BUG #11466: Copying files with vfs_fruit fails when using vfs_streams_xattr without stream prefix and type suffix.
  • BUG #11645: smbd: Make "hide dot files" option work with "store dos attributes = yes".
  • Günther Deschner <gd@samba.org>
  • BUG #11639: lib/async_req: Do not install async_connect_send_test.

o Stefan Metzmacher <metze@samba.org>

  • BUG #11394: Crash: Bad talloc magic value - access after free.
  • Rowland Penny <repenny241155@gmail.com>
  • BUG #11613: samba-tool: Fix uncaught exception if no fSMORoleOwner attribute is given.
  • Karolin Seeger <kseeger@samba.org>
  • BUG #11619: docs: Fix some typos in the idmap backend section.
  • BUG #11641: docs: Fix typos in man vfs_gpfs.
  • Uri Simchoni <uri@samba.org>
  • BUG #11649: smbd: Do not disable "store dos attributes" on-the-fly.
https://www.samba.org/samba/history/samba-4.3.4.html

Samba 4.3.3

Release Notes for Samba 4.3.3
December 16, 2015

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

  • CVE-2015-3223 (Denial of service in Samba Active Directory server)
  • CVE-2015-5252 (Insufficient symlink verification in smbd)
  • CVE-2015-5299 (Missing access control check in shadow copy code)
  • CVE-2015-5296 (Samba client requesting encryption vulnerable to downgrade attack)
  • CVE-2015-8467 (Denial of service attack against Windows Active Directory server)
  • CVE-2015-5330 (Remote memory read in Samba LDAP server)

Please note that if building against a system libldb, the required version has been bumped to ldb-1.1.24. This is needed to ensure we build against a system ldb library that contains the fixes for CVE-2015-5330 and CVE-2015-3223.

Details

All versions of Samba from 4.0.0 to 4.3.2 inclusive (resp. all ldb versions up to 1.1.23 inclusive) are vulnerable to a denial of service attack in the samba daemon LDAP server.
A malicious client can send packets that cause the LDAP server in the samba daemon process to become unresponsive, preventing the server from servicing any other requests.
This flaw is not exploitable beyond causing the code to loop expending CPU resources.
All versions of Samba from 3.0.0 to 4.3.2 inclusive are vulnerable to a bug in symlink verification, which under certain circumstances could allow client access to files outside the exported share path.
If a Samba share is configured with a path that shares a common path prefix with another directory on the file system, the smbd daemon may allow the client to follow a symlink pointing to a file or directory in that other directory, even if the share parameter "wide links" is set to "no" (the default).
All versions of Samba from 3.2.0 to 4.3.2 inclusive are vulnerable to a missing access control check in the vfs_shadow_copy2 module. When looking for the shadow copy directory under the share path the current accessing user should have DIRECTORY_LIST access rights in order to view the current snapshots.
This was not being checked in the affected versions of Samba.
Versions of Samba from 3.2.0 to 4.3.2 inclusive do not ensure that signing is negotiated when creating an encrypted client connection to a server.
Without this a man-in-the-middle attack could downgrade the connection and connect using the supplied credentials as an unsigned, unencrypted connection.
Samba, operating as an AD DC, is sometimes operated in a domain with a mix of Samba and Windows Active Directory Domain Controllers.
All versions of Samba from 4.0.0 to 4.3.2 inclusive, when deployed as an AD DC in the same domain with Windows DCs, could be used to override the protection against the MS15-096 / CVE-2015-2535 security issue in Windows.
Prior to MS16-096 it was possible to bypass the quota of machine accounts a non-administrative user could create. Pure Samba domains are not impacted, as Samba does not implement the SeMachineAccountPrivilege functionality to allow non-administrator users to create new computer objects.
All versions of Samba from 4.0.0 to 4.3.2 inclusive (resp. all ldb versions up to 1.1.23 inclusive) are vulnerable to a remote memory read attack in the samba daemon LDAP server.
A malicious client can send packets that cause the LDAP server in the samba daemon process to return heap memory beyond the length of the requested value.
This memory may contain data that the client should not be allowed to see, allowing compromise of the server.
The memory may either be returned to the client in an error string, or stored in the database by a suitabily privileged user. If untrusted users can create objects in your database, please confirm that all DN and name attributes are reasonable.

Changes since 4.3.3:

  • Andrew Bartlett <abartlet@samba.org>
  • Jeremy Allison <jra@samba.org>
  • Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
  • Stefan Metzmacher <metze@samba.org>
https://www.samba.org/samba/history/samba-4.3.3.html

Samba 4.3.2

Release Notes for Samba 4.3.2
December 01, 2015

This is the latest stable release of Samba 4.3.

Changes since 4.3.1:

  • Michael Adam <obnox@samba.org>
  • BUG #11577: ctdb: Open the RO tracking db with perms 0600 instead of 0000.
  • Jeremy Allison <jra@samba.org>
  • BUG #10252: s3-smbd: Fix old DOS client doing wildcard delete - gives an attribute type of zero.
  • BUG #11565: auth: gensec: Fix a memory leak.
  • BUG #11566: lib: util: Make non-critical message a warning.
  • BUG #11589: s3: smbd: If EAs are turned off on a share don't allow an SMB2 create containing them.
  • BUG #11615: s3: smbd: have_file_open_below() fails to enumerate open files below an open directory handle.
  • Ralph Boehme <slow@samba.org>
  • BUG #11562: s4:lib/messaging: Use correct path for names.tdb.
  • BUG #11564: async_req: Fix non-blocking connect().
  • Volker Lendecke <vl@samba.org>
  • BUG #11243: vfs_gpfs: Re-enable share modes.
  • BUG #11570: smbd: Send SMB2 oplock breaks unencrypted.
  • BUG #11612: winbind: Fix crash on invalid idmap configs.
  • YvanM <yvan.masson@openmailbox.org>
  • Stefan Metzmacher <metze@samba.org>
  • BUG #11327: dcerpc.idl: Accept invalid dcerpc_bind_nak pdus.
  • BUG #11581: s3:smb2_server: Make the logic of SMB2_CANCEL DLIST_REMOVE() clearer.
  • Marc Muehlfeld <mmuehlfeld@samba.org>
  • BUG #9912: Changing log level of two entries to DBG_NOTICE.
  • BUG #11581: s3-smbd: Fix use after issue in smbd_smb2_request_dispatch().
  • Noel Power <noel.power@suse.com>
  • BUG #11569: Fix winbindd crashes with samlogon for trusted domain user.
  • BUG #11597: Backport some valgrind fixes from upstream master.
  • Andreas Schneider <asn@samba.org
  • BUG #11563: Fix segfault of 'net ads (join|leave) -S INVALID' with nss_wins.
  • Tom Schulz <schulz@adi.com>
  • BUG #11511: Add libreplace dependency to texpect, fixes a linking error on Solaris.
  • BUG #11512: s4: Fix linking of 'smbtorture' on Solaris.
  • Uri Simchoni <uri@samba.org>
  • BUG #11608: auth: Consistent handling of well-known alias as primary gid.
https://www.samba.org/samba/history/samba-4.3.2.html

Samba 4.3.1

Release Notes for Samba 4.3.1
October 20, 2015

This is the latest stable release of Samba 4.3.

Changes since 4.3.0:

  • Jeremy Allison <jra@samba.org>
  • BUG #10252: s3: smbd: Fix our access-based enumeration on "hide unreadable" to match Windows.
  • BUG #10634: smbd: Fix file name buflen and padding in notify repsonse.
  • BUG #11486: s3: smbd: Fix mkdir race condition.
  • BUG #11522: s3: smbd: Fix opening/creating :stream files on the root share directory.
  • BUG #11535: s3: smbd: Fix NULL pointer bug introduced by previous 'raw'
  • BUG #11522:stream fix .
  • BUG #11555: s3: lsa: lookup_name() logic for unqualified (no DOMAIN\component) names is incorrect.
  • Ralph Boehme <slow@samba.org>
  • BUG #11535: s3: smbd: Fix a crash in unix_convert().
  • BUG #11543: vfs_fruit: Return value of ad_pack in vfs_fruit.c.
  • BUG #11549: s3:locking: Initialize lease pointer in share_mode_traverse_fn().
  • BUG #11550: s3:smbstatus: Add stream name to share_entry_forall().
  • BUG #11555: s3:lib: Validate domain name in lookup_wellknown_name().
  • Günther Deschner <gd@samba.org>
  • BUG #11038: kerberos: Make sure we only use prompter type when available.
  • Volker Lendecke <vl@samba.org>
  • BUG #11038: winbind: Fix 100% loop.
  • BUG #11053: source3/lib/msghdr.c: Fix compiling error on Solaris.
  • Stefan Metzmacher <metze@samba.org>
  • BUG #11316: s3:ctdbd_conn: make sure we destroy tevent_fd before closing the socket.
  • BUG #11515: s4:lib/messaging: Use 'msg.lock' and 'msg.sock' for messaging related subdirs.
  • BUG #11526: lib/param: Fix hiding of FLAG_SYNONYM values.
  • Björn Jacke <bj@sernet.de>
  • BUG #10973: nss_winbind: Fix hang on Solaris on big groups.
  • BUG #11355: build: Use as-needed linker flag also on OpenBSD.
  • Har Gagan Sahai <SHarGagan@novell.com>
  • Andreas Schneider <asn@samba.org>
  • Uri Simchoni <uri@samba.org>
https://www.samba.org/samba/history/samba-4.3.1.html

Samba 4.3.0

Release Notes for Samba 4.3.0
September 8, 2015

This is the first stable release of Samba 4.3.

UPGRADING

Read the "New FileChangeNotify subsystem" and "smb.conf changes" sections (below).


NEW FEATURES

Logging

The logging code now supports logging to multiple backends. In addition to the previously available syslog and file backends, the backends for logging to the systemd-journal, lttng and gpfs have been added. Please consult the section for the 'logging' parameter in the smb.conf manpage for details.

Spotlight

Support for Apple's Spotlight has been added by integrating with Gnome Tracker.

For detailed instructions how to build and setup Samba for Spotlight, please see here.

New FileChangeNotify subsystem

Samba now contains a new subsystem to do FileChangeNotify. The previous system used a central database, notify_index.tdb, to store all notification requests. In particular in a cluster this turned out to be a major bottleneck, because some hot records need to be bounced back and forth between nodes on every change event like a new created file.

The new FileChangeNotify subsystem works with a central daemon per node. Every FileChangeNotify request and every event are handled by an asynchronous message from smbd to the notify daemon. The notify daemon maintains a database of all FileChangeNotify requests in memory and will distribute the notify events accordingly. This database is asynchronously distributed in the cluster by the notify daemons.

The notify daemon is supposed to scale a lot better than the previous implementation. The functional advantage is cross-node kernel change notify: Files created via NFS will be seen by SMB clients on other nodes per FileChangeNotify, despite the fact that popular cluster file systems do not offer cross-node inotify.

Two changes to the configuration were required for this new subsystem:

The parameters "change notify" and "kernel change notify" are not per-share anymore but must be set globally. So it is no longer possible to enable or disable notify per share, the notify daemon has no notion of a share, it only works on absolute paths.

New SMB profiling code

The code for SMB (SMB1, SMB2 and SMB3) profiling uses a tdb instead of sysv IPC shared memory. This avoids performance problems and NUMA effects. The profile stats are a bit more detailed than before.

Improved DCERPC man in the middle detection for kerberos

The gssapi based kerberos backends for gensec have support for DCERPC header signing when using DCERPC_AUTH_LEVEL_PRIVACY.

SMB signing required in winbindd by default

The effective value for "client signing" is required by default for winbindd, if the primary domain uses active directory.

Experimental NTDB was removed

The experimental NTDB library introduced in Samba 4.0 has been removed again.

Improved support for trusted domains (as AD DC)

The support for trusted domains/forests has improved a lot.

samba-tool got "domain trust" subcommands to manage trusts:

 create      - Create a domain or forest trust.
 delete      - Delete a domain trust.
 list        - List domain trusts.
 namespaces  - Manage forest trust namespaces.
 show        - Show trusted domain details.
 validate    - Validate a domain trust.

External trusts between individual domains work in both ways (inbound and outbound). The same applies to root domains of a forest trust. The transitive routing into the other forest is fully functional for kerberos, but not yet supported for NTLMSSP.

While a lot of things are working fine, there are currently a few limitations:

  • Both sides of the trust need to fully trust each other!
  • No SID filtering rules are applied at all!
  • This means DCs of domain A can grant domain admin rights in domain B.
  • It's not possible to add users/groups of a trusted domain into domain groups.

SMB 3.1.1 supported

Both client and server have support for SMB 3.1.1 now.

This is the dialect introduced with Windows 10, it improves the secure negotiation of SMB dialects and features.

There's also a new optinal encryption algorithm aes-gcm-128, but for now this is only selected as fallback and aes-ccm-128 is preferred because of the better performance. This might change in future versions when hardware encryption will be supported.

See BUG #11451

New smbclient subcommands

  • Query a directory for change notifications: notify <dir name>
  • Server side copy: scopy <source filename> <destination filename>

New rpcclient subcommands

 netshareenumall 	- Enumerate all shares
 netsharegetinfo 	- Get Share Info
 netsharesetinfo 	- Set Share Info
 netsharesetdfsflags	- Set DFS flags
 netfileenum		- Enumerate open files
 netnamevalidate	- Validate sharename
 netfilegetsec		- Get File security
 netsessdel		- Delete Session
 netsessenum		- Enumerate Sessions
 netdiskenum		- Enumerate Disks
 netconnenum		- Enumerate Connections
 netshareadd		- Add share
 netsharedel		- Delete share

New modules

 idmap_script 		- see 'man 8 idmap_script'
 vfs_unityed_media	- see 'man 8 vfs_unityed_media'
 vfs_shell_snap	- see 'man 8 vfs_shell_snap'

New sparsely connected replia graph (Improved KCC)

The Knowledge Consistency Checker (KCC) maintains a replication graph for DCs across an AD network. The existing Samba KCC uses a fully connected graph, so that each DC replicates from all the others, which does not scale well with large networks. In 4.3 there is an experimental new KCC that creates a sparsely connected replication graph and closely follows Microsoft's specification. It is turned off by default. To use the new KCC, set "kccsrv:samba_kcc=true" in smb.conf and let us know how it goes. You should consider doing this if you are making a large new network. For small networks there is little benefit and you can always switch over at a later date.

Configurable TLS protocol support, with better defaults

The "tls priority" option can be used to change the supported TLS protocols. The default is to disable SSLv3, which is no longer considered secure.

Samba-tool now supports all 7 FSMO roles

Previously "samba-tool fsmo" could only show, transfer or seize the five well-known FSMO roles:

  • Schema Master
  • Domain Naming Master
  • RID Master
  • PDC Emulator
  • Infrastructure Master

It can now also show, transfer or seize the DNS infrastructure roles:

  • DomainDnsZones Infrastructure Master
  • ForestDnsZones Infrastructure Master

CTDB logging changes

The destination for CTDB logging is now set via a single new configuration variable CTDB_LOGGING. This replaces CTDB_LOGFILE and CTDB_SYSLOG, which have both been removed. See ctdbd.conf(5) for details of CTDB_LOGGING.

CTDB no longer runs a separate logging daemon.

CTDB NFS support changes

CTDB's NFS service management has been combined into a single 60.nfs event script. This updated 60.nfs script now uses a call-out to interact with different NFS implementations. See the CTDB_NFS_CALLOUT option in the ctdbd.conf(5) manual page for details. A default call-out is provided to interact with the Linux kernel NFS implementation. The 60.ganesha event script has been removed - a sample call-out is provided for NFS Ganesha, based on this script.

The method of configuring NFS RPC checks has been improved. See ctdb/config/nfs-checks.d/README for details.

Improved Cross-Compiling Support=

A new "hybrid" build configuration mode is added to improve cross-compilation support.

A common challenge in cross-compilation is that of obtaining the results of tests that have to run on the target, during the configuration phase of the build. The Samba build system already supports the following means to do so:

  • Executing configure tests using the --cross-execute parameter
  • Obtaining the results from an answers file using the --cross-answers parameter

The first method has the drawback of inaccurate results if the tests are run using an emulator, or a need to be connected to a running target while building, if the tests are to be run on an actual target. The second method presents a challenge of figuring out the test results.

The new hybrid mode runs the tests and records the result in an answer file. To activate this mode, use both --cross-execute and --cross-answers in the same configure invocation. This mode can be activated once against a running target, and then the generated answers file can be used in subsequent builds.

Also supplied is an example script that can be used as the cross-execute program. This script copies the test to a running target and runs the test on the target, obtaining the result. The obtained results are more accurate than running the test with an emulator, because they reflect the exact kernel and system libraries that exist on the target.

Improved Sparse File Support


Support for the FSCTL_SET_ZERO_DATA and FSCTL_QUERY_ALLOCATED_RANGES SMB2 requests has been added to the smbd file server.

This allows for clients to deallocate (hole punch) regions within a sparse file, and check which portions of a file are allocated.

Changes

smb.conf changes

 Parameter Name		Description		Default
 logging			New			(empty)
 msdfs shuffle referrals	New			no
 smbd profiling level		New			off
 spotlight			New			no
 tls priority			New 			NORMAL:-VERS-SSL3.0
 use ntdb			Removed
 change notify			Changed to [global]
 kernel change notify		Changed to [global]
 client max protocol		Changed	default		SMB3_11
 server max protocol		Changed default		SMB3_11

Removed modules

vfs_notify_fam - see section 'New FileChangeNotify subsystem'.

KNOWN ISSUES

Currently none.

CHANGES SINCE 4.3.0rc4

  • Andrew Bartlett <abartlet@samba.org>
  • BUG #10973: No objectClass found in replPropertyMetaData on ordinary objects (non-deleted)
  • BUG #11429: Python bindings don't check integer types
  • BUG #11430: Python bindings don't check array sizes
  • Ralph Boehme <slow@samba.org>
  • BUG #11467: Handling of 0 byte resource fork stream
  • Volker Lendecke <vl@samba.org>
  • BUG #11488: AD samr GetGroupsForUser fails for users with "()" in their name
  • Stefan Metzmacher <metze@samba.org>
  • BUG #11429: Python bindings don't check integer types
  • Matthieu Patou <mat@matws.net>
  • BUG #10973: No objectClass found in replPropertyMetaData on ordinary objects (non-deleted)

CHANGES SINCE 4.3.0rc3

  • Ralph Boehme <slow@samba.org>
  • BUG #11444: Crash in notify_remove caused by change notify = no
  • Günther Deschner <gd@samba.org>
  • BUG #11411: smbtorture does not build when configured --with-system-mitkrb5
  • Volker Lendecke <vl@samba.org>
  • BUG #11455: fix recursion problem in rep_strtoll in lib/replace/replace.c
  • BUG #11464: xid2sid gives inconsistent results
  • BUG #11465: ctdb: Fix the build on FreeBSD 10.1
  • Roel van Meer <roel@1afa.com>
  • BUG #11427: nmbd incorrectly matches netbios names as own name
  • Stefan Metzmacher <metze@samba.org>
  • BUG #11451: Poor SMB3 encryption performance with AES-GCM
  • BUG #11458: --bundled-libraries=!ldb,!pyldb,!pyldb-util doesn't disable ldb build and install
  • Andreas Schneider <asn@samba.org>
  • BUG #9862: Samba "map to guest = Bad uid" doesn't work

CHANGES SINCE 4.3.0rc2

  • Andrew Bartlett <abartlet@samba.org>
  • BUG #11436: samba-tool uncaught exception error
  • BUG #10493: revert LDAP extended rule 1.2.840.113556.1.4.1941 LDAP_MATCHING_RULE_IN_CHAIN changes
  • Ralph Boehme <slow@samba.org>
  • BUG #11278: Stream names with colon don't work with fruit:encoding = native
  • BUG #11426: net share allowedusers crashes
  • Amitay Isaacs <amitay@gmail.com>

o Stefan Metzmacher <metze@samba.org>

  • BUG #11451: Poor SMB3 encryption performance with AES-GCM (part1)
  • BUG #11316: tevent_fd needs to be destroyed before closing the fd

o Arvid Requate <requate@univention.de>

  • BUG #11291: NetApp joined to a Samba/ADDC cannot resolve SIDs

o Martin Schwenke <martin@meltin.net>


CHANGES SINCE 4.3.0rc1

  • Jeremy Allison <jra@samba.org>
  • Björn Baumbach <bb@sernet.de>
  • Justin Maggard <jmaggard@netgear.com>
  • BUG #11320: "force group" with local group not working
  • Martin Schwenke <martin@meltin.net
https://www.samba.org/samba/history/samba-4.3.0.html