Use correct netbios name when leaving a domain joined with net ads

[Andreas Hasenack]

WHen a domain was joined using samba as the join software (i.e., net ads join was used), and a custom computer name was specified, then this same name should be used when leaving the domain with the -r option, to remove the computer. Otherwise the "net ads leave" command will try to use the hostname and won't find it in AD:

# joining with a custom name of GG, whereas hostname is g-adclient1:
root@g-adclient1:~# realm -v join ad1.example.com --client-software=winbind --computer-name=GG
 * Resolving: _ldap._tcp.ad1.example.com
 * Performing LDAP DSE lookup on: 10.51.0.5
 * Successfully discovered: ad1.example.com
 * Unconditionally checking packages
 * Resolving required packages
 * Joining using a manual netbios name: GG
 * LANG=C LOGNAME=root KRB5CCNAME=/var/cache/realmd/realm-ad-kerberos-8GVPQ0 /usr/bin/net -s /var/cache/realmd/realmd-smb-conf.6BYEQ0 -k ads join ad1.example.com
DNS update failed: NT_STATUS_INVALID_PARAMETER
Using short domain name -- AD1
Joined 'GG' to dns domain 'ad1.example.com'
No DNS domain configured for gg. Unable to perform DNS Update.
 * LANG=C LOGNAME=root KRB5CCNAME=/var/cache/realmd/realm-ad-kerberos-8GVPQ0 /usr/bin/net -s /var/cache/realmd/realmd-smb-conf.6BYEQ0 -k ads keytab create
 * /usr/sbin/update-rc.d winbind enable
 * /usr/sbin/service winbind restart
 * Successfully enrolled machine in realm

Computer entry created with the name GG:
root@g-adclient1:~# ldapsearch '(|(cn=GG)(cn=G-ADCLIENT1))' dn
dn: CN=GG,CN=Computers,DC=ad1,DC=example,DC=com

Leaving fails to find the computer, as it looks for g-adclient1:
root@g-adclient1:~# realm -v leave ad1.example.com --client-software=winbind -r
Password for Administrator:
 * LANG=C LOGNAME=root /usr/bin/net -s /var/cache/realmd/realmd-smb-conf.JRDKQ0 -U Administrator ads leave
Enter Administrator's password:Host account for g-adclient1 does not exist.

Failed to leave domain: failed to leave realm: No such object
 ! Leaving the domain ad1.example.com failed
 * Removing entries from keytab for realm
 * Updating smb.conf file
 * /usr/sbin/update-rc.d winbind disable
 * /usr/sbin/service winbind stop
 * Successfully unenrolled machine from realm

root@g-adclient1:~# ldapsearch '(|(cn=GG)(cn=G-ADCLIENT1))' dn
dn: CN=GG,CN=Computers,DC=ad1,DC=example,DC=com

[Launchpad Janitor (janitor)]

This bug was fixed in the package realmd - 0.16.3-3ubuntu1

---------------
realmd (0.16.3-3ubuntu1) groovy; urgency=medium

  * d/p/0001-LDAP-don-t-close-LDAP-socket-twice.patch: don't close LDAP
    socket twice.
  * d/p/0001-Fix-man-page-reference-in-systemd-service-file.patch: the
    manpage is realm(8), not realmd(8)
  * d/p/0001-Use-current-idmap-options-for-smb.conf.patch: use the
    idmap options in smb.conf for modern versions of samba (LP: #1894153)
  * d/p/0001-Find-NetBIOS-name-in-keytab-while-leaving.patch: find
    NetBIOS name in keytab while leaving the domain (LP: #1894340)
  * d/p/0001-Fix-issues-found-by-Coverity.patch: fix issues found by
    Coverity
  * d/p/0002-Change-qualified-names-default-for-IPA.patch: change
    qualified names default for IPA
  * d/p/0003-discover-try-to-get-domain-name-from-hostname.patch: if
    there is no domain name returned by DHCP check if the hostname
    contains a domain part and use this to discover a realm.
  * d/p/0001-IPA-do-not-call-sssd-enable-logins.patch: IPA: do not call
    sssd-enable-logins
  * d/p/0001-Set-NEWEST-flag-when-resolving-packages-with-Package.patch:
    install the latest version of a package when resolving packages with
    PackageKit
  * d/p/0001-doc-make-sure-cross-reference-ids-are-predictable.patch: make
    sure cross-reference ids are predictable
  * d/p/0002-tools-remove-duplicated-va_start.patch: remove duplicated
    va_start()
  * d/p/0003-service-remove-dead-code.patch: remove unused code
  * d/p/0004-service-check-return-value-of-fcntl.patch: check return
    value of fcntl()
  * d/p/0005-service-avoid-dereference-of-a-null-pointer.patch: avoid
    dereference of a null pointer
  * d/p/0006-service-avoid-dereferencing-a-NULL-pointer.patch: avoid
    dereferencing a NULL pointer
  * d/p/0001-Add-missing-xsl-file-to-Makefile.am.patch: add missing xsl
    file to Makefile.am
  * d/p/0002-configure-do-not-inherit-DISTRO-from-the-environment.patch:
    do not inherit DISTRO from the environment
  * d/p/0003-doc-extend-user-principal-section.patch: doc: extend
    user-principal section
  * d/p/0004-doc-fix-discover-name-only.patch: doc: fix discover
    name-only parameter
  * d/p/0005-doc-add-see-also-to-man-pages.patch: doc: add see also to
    man pages
  * d/p/0006-doc-extend-description-of-config-handling.patch: doc: extend
    description of config handling
  * d/p/0007-service-use-kerberos-method-secrets-and-keytab.patch: when
    using Samba with Winbind, set "kerberos method" to "secrets and keytab"
  * d/p/install-libnss-winbind.patch: install libnss-winbind when needed
    (LP: #1894150)
  * d/p/dont-add-services-line.patch: in Ubuntu and Debian, the sssd_*
    services are socket activated and don't need a "services" line in
    sssd.conf (LP: #1880157)
  * d/p/0004-service-use-additional-dns-hostnames-with-net-ads-jo.patch:
    when using samba to join a domain, and the client is from a different
    domain, also set "additional dns hostnames"
  * d/p/0002-Use-startTLS-with-FreeIPA.patch: attempt StartTLS first
    when talking to FreeIPA
  * d/p/0003-service-use-net-ads-join-with-k-for-user-join-as-wel.patch:
    when joining using samba, ...