Bug 2190417

Rebase Samba to the latest 4.18.x release.


NEW FEATURES/CHANGES
====================

SMB Server performance improvements
-----------------------------------

The security improvements in recent releases
(4.13, 4.14, 4.15, 4.16), mainly as protection against symlink races,
caused performance regressions for metadata heavy workloads.

While 4.17 already improved the situation quite a lot,
with 4.18 the locking overhead for contended path based operations
is reduced by an additional factor of ~ 3 compared to 4.17.
It means the throughput of open/close
operations reached the level of 4.12 again.

More succinct samba-tool error messages
---------------------------------------

Historically samba-tool has reported user error or misconfiguration by
means of a Python traceback, showing you where in its code it noticed
something was wrong, but not always exactly what is amiss. Now it
tries harder to identify the true cause and restrict its output to
describing that. Particular cases include:

 * a username or password is incorrect
 * an ldb database filename is wrong (including in smb.conf)
 * samba-tool dns: various zones or records do not exist
 * samba-tool ntacl: certain files are missing
 * the network seems to be down
 * bad --realm or --debug arguments

Accessing the old samba-tool messages
-------------------------------------

This is not new, but users are reminded they can get the full Python
stack trace, along with other noise, by using the argument '-d3'.
This may be useful when searching the web.

The intention is that when samba-tool encounters an unrecognised
problem (especially a bug), it will still output a Python traceback.
If you encounter a problem that has been incorrectly identified by
samba-tool, please report it on https://bugzilla.samba.org.

Colour output with samba-tool --color
-------------------------------------

For some time a few samba-tool commands have had a --color=yes|no|auto
option, which determines whether the command outputs ANSI colour
codes. Now all samba-tool commands support this option, which now also
accepts 'always' and 'force' for 'yes', 'never' and 'none' for 'no',
and 'tty' and 'if-tty' for 'auto' (this more closely matches
convention). With --color=auto, or when --color is omitted, colour
codes are only used when output is directed to a terminal.

Most commands have very little colour in any case. For those that
already used it, the defaults have changed slightly.

 * samba-tool drs showrepl: default is now 'auto', not 'no'
 
 * samba-tool visualize: the interactions between --color-scheme,
   --color, and --output have changed slightly. When --color-scheme is
   set it overrides --color for the purpose of the output diagram, but
   not for other output like error messages.

New samba-tool dsacl subcommand for deleting ACES
-------------------------------------------------

The samba-tool dsacl tool can now delete entries in directory access
control lists. The interface for 'samba-tool dsacl delete' is similar
to that of 'samba-tool dsacl set', with the difference being that the
ACEs described by the --sddl argument are deleted rather than added.

No colour with NO_COLOR environment variable
--------------------------------------------

With both samba-tool --color=auto (see above) and some other places
where we use ANSI colour codes, the NO_COLOR environment variable will
disable colour output. See https://no-color.org/ for a description of
this variable. `samba-tool --color=always` will use colour regardless
of NO_COLOR.

New wbinfo option --change-secret-at
------------------------------------

The wbinfo command has a new option, --change-secret-at=<DOMAIN CONTROLLER>
which forces the trust account password to be changed at a specified domain
controller. If the specified domain controller cannot be contacted the
password change fails rather than trying other DCs.

New option to change the NT ACL default location
------------------------------------------------

Usually the NT ACLs are stored in the security.NTACL extended
attribute (xattr) of files and directories. The new
"acl_xattr:security_acl_name" option allows to redefine the default
location. The default "security.NTACL" is a protected location, which
means the content of the security.NTACL attribute is not accessible
from normal users outside of Samba. When this option is set to use a
user-defined value, e.g. user.NTACL then any user can potentially
access and overwrite this information. The module prevents access to
this xattr over SMB, but the xattr may still be accessed by other
means (eg local access, SSH, NFS). This option must only be used when
this consequence is clearly understood and when specific precautions
are taken to avoid compromising the ACL content.

Azure Active Directory / Office365 synchronisation improvements
--------------------------------------------------------------

Use of the Azure AD Connect cloud sync tool is now supported for
password hash synchronisation, allowing Samba AD Domains to synchronise
passwords with this popular cloud environment.

REMOVED FEATURES
================


smb.conf changes
================

  Parameter Name                          Description     Default
  --------------                          -----------     -------
  acl_xattr:security_acl_name             New             security.NTACL
  server addresses                        New