Updating Samba
Introduction
The following documentation describes the process of updating Samba to a newer version.
If you want to migrate a Samba NT4 domain to Samba Active Directory (AD), see Migrating a Samba NT4 Domain to Samba AD (Classic Upgrade).
Misconceptions About Samba 4
If you update to Samba 4 and later, you do not have to migrate to Active Directory. |
The Active Directory (AD) Domain Controller (DC) support is one of the enhancements introduced in Samba 4.0. However all newer versions include the features of previous versions - including the NT4-style (classic) domain support. This means you can update a Samba 3.x NT4-style primary domain controller (PDC) to a recent version, as you previously updated, for example from 3.4.x to 3.5.x. There is no need to migrate an NT4-style domain to an AD.
Additionally, all recent versions continue to support setting up a new NT4-style PDC. The AD support in Samba 4.0 and later is optional and does not replace any of the PDC features. The Samba team understand the difficulty presented by existing LDAP structures. For that reason, there is no plan to remove the classic PDC support. Additionally we continue testing the PDC support in our continuous integration system.
The Update Process
Run the following steps, whether you are updating a Samba Active Directory (AD) domain controller (DC), a Samba NT4-style PDC, a Samba domain member, or a standalone installation:
- Stop all Samba services.
- Create a backup.
- Read the release notes of skipped versions. They contain important information, such as new features, changed parameter, and bug fixes. In case you switch to new major release, read the release notes of the initial version (x.y.0) and the ones from minor versions up to the new version you will update to. For example, if you update from 4.4.4 to 4.6.2, read the 4.5.0, 4.6.0, 4.6.1, and 4.6.2 release notes.
- Install the latest version over your existing one:
- If you compile Samba from the sources, use the same
configure
options as used for your previous version. For more information, see Build Samba From the Sources.
- If you compile Samba from the sources, use the same
- If you update using packages, read the distribution documentation for information how to update.
- Start Samba.
- Start the same daemons as on your previous version:
- On Samba AD DCs:
samba
- On Samba NT4-style PDC/BDCs:
smbd
,nmbd
- On Samba domain members:
smbd
,nmbd
(winbind
, if used) - On Samba standalone hosts:
smbd
- On Samba AD DCs:
- On Samba AD DCs only: Run the Samba AD DC database check.
- Check your Samba log files for errors.
- Test your updated installation.
Updating Multiple Samba Domain Controllers
If you are updating multiple Samba Active Directory (AD) Domain Controllers (DC), the recommended order is:
- Update one Samba AD DC that does not hold any flexible single master operations (FSMO) role.
- Start Samba on the updated DC.
- Verify that the directory replication between all DCs is working correctly:
# samba-tool drs showrepl
- Test the installation to ensure that the new version works correctly.
- Upgrade all other Samba DCs one at a time and always verify that the replication is working correctly.
Samba AD DC Database Check
The samba-tool
utility enables you to detect and fix problems in the Samba Active Directory (AD) database. For example, if a previous Samba version stored an attribute incorrectly and the updated version fixes the problem. You must run the check and fix command on every Samba AD DC locally, because some fixes apply to non-replicated attributes and modifications are not replicated to other DCs.
To check the AD database, run:
# samba-tool dbcheck --cross-ncs
To fix reported errors, run:
# samba-tool dbcheck --cross-ncs --fix
If you pass the --yes
parameter to the command, all questions are automatically answered with yes
. Note that if you omit the --yes
parameter, the database check executes three fsync()
calls for each object. This can result in a longer run duration. For example, passing the --yes
parameter to the command fixed 3500 objects in 10 seconds in our test environment. Without this parameter, the command required 4:50 minutes for the same operation.
After a repair, re-check the database to verify a successful operation.
Notable Enhancements and Changes
If you are updating Samba, always read the release notes of all versions between the previous and the one you are updating to. They contain important and additional information on new features, changed parameter options, and so on.
This section provides an overview about important changes that require your attention to fix problems of previous versions, avoid a negative performance impact, and so on.
Changes Affecting All Samba Installation Modes
File Execution Permissions
4.0.0 and later
Previously, Samba did not check the execution bit of files. As a consequence, users could execute files, such as *.exe
and *.bat
, on a share, if the x-bit was not set. Samba has been enhanced and now denies to execute a file if the x-bit is not set. In situations, such as when upgrading from a previous version, your executable files can be missing the x-bit. As a workaround, you can enable the old behaviour, if you set the following parameter for individual shares or in the [global]
section:
acl allow execute always = yes
Samba Active Directory Domain Controllers
The ntvfs
File Server Back End Has Been Disabled
4.5.0 and later
Previously, Samba enabled users to provision a domain controller (DC) using the ntvfs
file server back end. This back end was never supported, and thus the ntvfs
feature is no longer build by default in Samba 4.5.0. Consequently, starting the samba
service on a DC using the ntvfs
back end failed after the update and the following error is logged:
[2016/09/01 08:00:00.000000, 0, pid=995] ../source4/smbd/service.c:98(server_service_startup) Failed to start service 'smb' - NT_STATUS_INVALID_SYSTEM_SERVICE [2016/09/01 08:00:00.000000, 0, pid=995] ../lib/util/become_daemon.c:111(exit_daemon) STATUS=daemon failed to start: Samba failed to start services, error code -1073741796
To fix the problem, migrate the file server back end on your DC to the supported s3fs
back end. For details, see Migrating the ntvfs File Server Back End to s3fs.
Fixing replPropertyMetaData Attributes
4.5.0 and later
Samba versions prior to 4.5.0 stored the replPropertyMetaData
attribute incorrectly. As a consequence, administrators could experience, for example, renaming conflicts. The problem has been fixed in 4.5.0 and later versions and Samba now stores the attribute correctly. The samba-tool
utility has been enhanced to detect incorrectly stored replPropertyMetaData
attributes:
# samba-tool dbcheck --cross-ncs
To fix the attributes, run:
# samba-tool dbcheck --cross-ncs --fix --yes ... CN=NTDS Settings,CN=DC1,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=samdom,DC=example,DC=com: 0x00000003 CN=NTDS Settings,CN=DC1,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=samdom,DC=example,DC=com: 0x00000000 ERROR: unsorted attributeID values in replPropertyMetaData on CN=NTDS Settings,CN=DC1,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=samdom,DC=example,DC=com Fix replPropertyMetaData on CN=NTDS Settings,CN=DC1,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=samdom,DC=example,DC=com by sorting the attribute list? [YES] Fixed attribute 'replPropertyMetaData' of 'CN=NTDS Settings,CN=DC1,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=samdom,DC=example,DC=com'
Note that the --yes
parameter automatically fixes all problems found and not only the replPropertyMetaData
attributes!
Run the check and fix operation on all Samba Domain Controllers (DC), because replPropertyMetaData
is a non-replicated attribute and modifications are not replicated to other DCs.
For more information, see the Samba AD DC database check section.
4.4.6 or later
The winbindd
service on a Samba Active Directory (AD) domain controller (DC) automatically uses the IDs set in the Active Directory uidNumber
and gidNumber
attributes of user accounts and groups. If the attributes are not set, Samba generates IDs locally on the DC and stores them in the idmap.ldb
database. Thus, on a Samba AD DC, idmap config
parameters set in the smb.conf
file were ignored. Due to a bug in Samba 4.4.6 and later, the parameters are no longer ignored and clients fail to connect to shares on the DC. To fix the problem:
- Remove all
idmap config
parameters in thesmb.conf
file on DCs. - Restart the
samba
service. - Restart the clients.
As a result, clients now correctly connect to shares on the DC.
New Default for LDAP Connections Requires Strong Authentication
4.4.1 or later / 4.3.7 or later / 4.2.10 or later
The security updates 4.4.1, 4.3.7 and 4.2.10 introduced a new smb.conf
option for the Active Directory (AD) LDAP server to enforce strong authentication. The default for this new option ldap server require strong auth
is yes
and allows only simple binds over TLS encrypted connections. In consequence, external applications that connect to AD using LDAP, cannot establish a connection if they do not use or support TLS encrypted connections.
Applications connecting to Samba AD using the LDAP protocol without encryption, will display the error message:
ldap_bind: Strong(er) authentication required (8) additional info: BindSimple: Transport encryption required.
For further information, see the 4.4.1, 4.3.7, or the 4.2.10 release notes.
AD Database Cleanup of Deleted LDAP DNS Entries
4.1.12 or later
Previously, Samba incorrectly created deleted Active Directory (AD) objects for removed DNS entries. The problem has been fixed. If you start the first Domain Controller (DC) with a fixed Samba version, all deleted objects are removed. As a result, this can result in a slow performance until the deleted objects are removed.
Incorrect TLS File Permissions
4.1.2 or later / 4.0.12 or later
Previously, Samba created the *.pem
files used for LDAP TLS encryptions with insecure permissions. To avoid insecure connections, delete the files on all domain controllers (DC):
# rm /usr/local/samba/private/tls/*.pem
Restart Samba after you deleted the files to automatically re-create the new certificates.
Fixing Dynamic DNS Update Problems
4.0.7 or later
See Fix DNS dynamic updates in Samba versions prior 4.0.7 for details.
Fixing Incorrect Sysvol and Directory ACLs
When updating from early 4.0.x versions, 4.0 beta and 4.0 release candidates.
- To reset wrong Sysvol ACLs, run:
# samba-tool ntacl sysvolreset
- To reset all well known ACLs in the directory, run:
# samba-tool dbcheck --cross-ncs --reset-well-known-acls --fix
- To fix errors in the Active Directory (AD) database, run:
# samba-tool dbcheck --cross-ncs --fix
Samba Domain Members
ID Mapping Configuration Verification
4.6.0 or later
Previously, Samba did not verified the ID mapping configuration in the smb.conf
file on a domain member. Thus, users could set an incorrect ID mapping configuration, such as overlapping ID ranges or incorrect back ends for the default domain. Consequently, the winbindd
service started and ID mapping failed or did not work as expected. The testparm
utility has been enhanced and now reports incorrect ID mapping configurations. For example:
ERROR: The idmap range for the domain * (tdb) overlaps with the range of SAMDOM (ad)!
ERROR: Do not use the 'ad' backend as the default idmap backend!
Additionally, when using an incorrect ID mapping configuration, the winbindd
service now fails to start and an error message is logged. For example:
[2017/03/01 12:00:00.000000, 0, pid=980] ../source3/winbindd/winbindd.c:1705(main) main: FATAL: Invalid idmap backend ad configured as the default backend!
Using Samba 4.6.0 and later, users are no longer able to use incorrect ID mapping configurations.
For further details, supported back ends on a domain member, and their configuration, see:
- Identity Mapping Back Ends
- the
IDENTITY MAPPING CONSIDERATIONS
section in thesmb.conf(5)
man page
The ad
ID Mapping Back End Now Supports Enabling RFC2307 or Template Mode Per-domain
4.6.0 or later
Previously, when the winbind nss info
parameter was set to rfc2307
, the Samba ad
ID mapping back end retrieved shell and home directory settings for all Active Directory (AD) domains from AD. In Samba 4.6.0, the new idmap config domain_name:unix_nss_info
parameter has been added. This parameter enables the administrator to set on a per-AD domain basis if the shell and home directory settings of users should be retrieved from AD or if the template settings, set in the template shell
and template homedir
parameters are applied.
The new idmap config domain_name:unix_nss_info
parameter has a higher priority than the global winbind nss info = rfc2307
setting. Therefore, using the idmap config domain_name:unix_nss_info = no
default setting for an AD domain, the shell and home directory are no longer retrieved from AD and the values set in the template shell
and template homedir
parameters are applied. To re-enable retrieving the values from AD for a domain, set in the [global]
section in your smb.conf
file:
idmap config domain_name:unix_nss_info = yes
For details and an example how to set up, see idmap config ad - Configuring the ad Back End.