Samba 3.6 Features added/changed

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Revision as of 13:48, 30 January 2012 by Fraz (talk | contribs) (→‎Samba 3.6.3)

Samba 3.6.3

Release Notes for Samba 3.6.3
January 29, 2012

This is a security release in order to address CVE-2012-0817.=

The Samba File Serving daemon (smbd) in Samba versions 3.6.0 to 3.6.2 is affected by a memory leak that can cause a server denial of service.

Samba 3.6.2

Release Notes for Samba 3.6.2
January 25, 2012

This is the latest stable release of Samba 3.6.2

Major enhancements in Samba 3.6.2 include:

  • Make Winbind receive user/group information bug #8371.
  • Several SMB2 fixes.
  • Release Bug 3.6.2 bug#8595.

Samba 3.6.1

Release Notes for Samba 3.6.1
October 20, 2011

This is the latest stable release of Samba 3.6.1

Major enhancements in Samba 3.6.1 include:

  • Fix smbd crashes triggered by Windows XP clients bug #8384.
  • Fix a Winbind race leading to 100% CPU load bug #8409.
  • Several SMB2 fixes.
  • The VFS ACL modules are no longer experimental but production-ready.

Samba 3.6.0

Release Notes for Samba 3.6.0
August 9, 2011

This is the first release of Samba 3.6.0.

Major enhancements in Samba 3.6.0 include:

Changed security defaults

Samba 3.6 has adopted a number of improved security defaults that will impact on existing users of Samba.

client ntlmv2 auth = yes
client use spnego principal = no
send spnego principal = no

The impact of 'client ntlmv2 auth = yes' is that by default we will not use NTLM authentication as a client. This applies to the Samba client tools such as smbclient and winbind, but does not change the separately released in-kernel CIFS client. To re-enable the poorer NTLM encryption set '--option=clientusentlmv2auth=no' on your smbclient command line, or set 'client ntlmv2 auth = no' in your smb.conf

The impact of 'client use spnego principal = no' is that Samba will use CIFS/hostname to obtain a kerberos ticket, acting more like Windows when using Kerberos against a CIFS server in smbclient, winbind and other Samba client tools. This will change which servers we will successfully negotiate kerberos connections to. This is due to Samba no longer trusting a server-provided hint which is not available from Windows 2008 or later. For correct operation with all clients, all aliases for a server should be recorded as a as a servicePrincipalName on the server's record in AD. (For this reason, this behavior change and parameter was also made in Samba 3.5.9)

The impact of 'send spnego principal = no' is to match Windows 2008 and not to send this principal, making existing clients give more consistent behaviour (more likely to fall back to NTLMSSP) between Samba and Windows 2008, and between Windows versions that did and no longer use this insecure hint.

SMB2 support

SMB2 support in 3.6.0 is fully functional (with one omission), and can be enabled by setting:

max protocol = SMB2

in the [global] section of your smb.conf and re-starting Samba. All features should work over SMB2 except the modification of user quotas using the Windows quota management tools.

As this is the first release containing what we consider to be a fully featured SMB2 protocol, we are not enabling this by default, but encourage users to enable SMB2 and test it. Once we have enough confirmation from Samba users and OEMs that SMB2 support is stable in wide user testing we will enable SMB2 by default in a future Samba release.

Internal Winbind passdb changes

Winbind has been changed to use the internal samr and lsa rpc pipe to get local user and group information instead of calling passdb functions. The reason is to use more of our infrastructure and test this infrastructure by using it. With this approach more code in Winbind is shared.

New Spoolss code

The spoolss and the old RAP printing code have been completely overhauled and refactored.

All calls from lanman/printing code has been changed to go through the spoolss RPC interfaces, this allows us to keep all checks in one place and avoid special cases in the main printing code. Printing code has been therefore confined within the spoolss code.

All the printing code, including the spoolss RPC interfaces has been changed to use the winreg RPC interfaces to store all data. All data has been migrated from custom, arbitrary TDB files to the registry interface. This transition allow us to present correct data to windows client accessing the server registry through the winreg RPC interfaces to query for printer data. Data is served out from a real registry implementation and therefore arguably 100% forward compatible.

Migration code from the previous TDB files formats is provided. This code is automatically invoked the first time the new code is run on the server. Although manual migration is also available using the 'net printer migrate' command.

These changes not only make all the spoolss code much more closer to "the spec", it also greatly improves our internal testing of both spoolss and winreg interfaces, and reduces overall code duplication.

As part of this work, new tests have been also added to increase coverage.

This code will also allow, in future, an easy transition to split out the spooling functions into a separate daemon for those OEMs that do not need printing functionality in their appliances, reducing the code footprint.

ID Mapping Changes

The id mapping configuration has been a source of much grief in the past. For this release, id mapping has been rewritten yet again with the goal of making the configuration more simple and more coherent while keeping the needed flexibility and even adding to the flexibility in some respects.

The major change that implies the configuration simplifications is at the heart of the id mapping system: The separation of the "idmap alloc system" that is responsible for the unix id counters in the tdb, tdb2 and ldap idmap backends from the id mapping code itself has been removed. The sids_to_unixids operation is now atomic and encapsulates (if needed) the action of allocating a unix id for a mapping that is to be created. Consequently all idmap alloc configuration parameters have vanished and it is hence now also not possible any more to specify an idmap alloc backend different from the idmap backend. Each idmap backend uses its own idmap unixid creation mechanism transparently.

As a consequence of the id mapping changes, the methods that are used for storing and deleting id mappings have been removed from the winbindd API. The "net idmap dump/restore" commands have been rewritten to not speak through winbindd any more but directly act on the databases. This is currently available for the tdb and tdb2 backends, the implementation for ldap still missing.

The allocate_id functionality is preserved for the unix id creator of the default idmap configuration is also used as the source of unix ids for the group mapping database and for the posix attributes in a ldapsam:editposix setup.

As part of the changes, the default idmap configuration has been changed to be more coherent with the per-domain configuration. The parameters "idmap uid", "idmap gid" and "idmap range" are now deprecated in favour of the systematic "idmap config * : range" and "idmap config * : backend" parameters. The reason for this change is that the old options only provided an incomplete and hence deceiving backwards compatibility, which was a source of many problems with upgrades. By introducing this change in configuration, it should be brought to the conciousness of the users that even the simple id mapping is not working exactly as in Samba 3.0 versions any more.

Endpoint Mapper

As Microsoft is more and more relying on endpoint mapper and we didn't have a complete implementation we decided to create an instance for Samba. The endpoint mapper is like a DNS server but for ports. If you want to talk to a certain RPC service over TCP/IP, you just ask the endpoint mapper on which port it is running. Then you can connect to the service and make sure that it is running.

The code is deactivated by default, because it needs more testing and it doesn't scale yet. If you want to enable and test the endpoint mapper you can set "rpc_server:epmapper = daemon" in the smb.conf file.

Internal restructuring

Ongoing internal restructuring for better separation of internal subsystem to achieve a faster build, smaller binaries and cleaner dependencies for the samba3 waf build.

SMB Traffic Analyzer

Added the new SMB Traffic Analyzer (SMBTA) VFS module protocol 2 featuring encryption, multiple arguments, and easier parseability. A new tool 'smbta-util' has been created to control the encryption behaviour of SMBTA. For compatibility, SMBTA by default operates on version 1. There are programs consuming the data that the module sends.

More information can be found on

NFS quota backend on Linux

A new nfs quota backend for Linux has been added that is based on the existing Solaris/FreeBSD implementation. This allows samba to communicate correct diskfree information for nfs imports that are re-exported as samba shares.


smb.conf changes

  Parameter Name                      Description     Default
  --------------                      -----------     -------
  async smb echo handler	       New	       No
  client ntlmv2 auth           Changed Default Yes
  client use spnego principal	       New	       No
  ctdb locktime warn threshold	       New	       0
  idmap alloc backend		       Removed
  log writeable files on exit	       New	       No
  multicast dns register	       New	       Yes
  ncalrpc dir			       New
  send spnego principal	       New	       No
  smb2 max credits		       New	       128
  smb2 max read		       New	       1048576
  smb2 max trans		       New	       1048576
  smb2 max write		       New	       1048576
  username map cache time	       New	       0
  winbind max clients		       New	       200
The variable substitutions for %i and %I no longer use IPv4 addresses mapped to IPv6, e.g. '::ffff:', if the host has IPv6 enabled. Now %i and %I contain just ''.

Commit Highlights

  • Michael Adam <>
    • ID Mapping changes.

  • Jeremy Allison <>
    • Implement SMB2 support.

  • Stefan Metzmacher <>
    • Implement SMB2 support.

  • Andreas Schneider <>
    • Add an Endpoint Mapper daemon.