nmbd hangs on service start if only the loopback interface is configured

[Brent Kerlin]

dist-upgrade from 16.04.1 to 16.10. Removed/purge package to finish upgrade and then tried to install again with same error.

ProblemType: Package
DistroRelease: Ubuntu 16.10
Package: samba (not installed)
ProcVersionSignature: Ubuntu 4.8.0-22.24-generic 4.8.0
Uname: Linux 4.8.0-22-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia
ApportVersion: 2.20.3-0ubuntu8
AptOrdering:
 samba:amd64: Install
 NULL: ConfigurePending
Architecture: amd64
Date: Thu Oct 20 10:54:15 2016
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2015-09-20 (396 days ago)
InstallationMedia: Xubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
RelatedPackageVersions:
 nautilus 1:3.20.3-1ubuntu3
 gvfs 1.28.2-1ubuntu2
SambaClientRegression: Yes
SourcePackage: samba
Title: package samba (not installed) failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to yakkety on 2016-10-20 (1 days ago)

[Robie Basak (racb)]

Thank you for taking the time to report this bug and helping to make Ubuntu better.

I am able to reproduce this as follows:

lxc launch ubuntu:yakkety samba-test
lxc exec samba-test bash
apt-get update && apt-get -y install samba
systemctl stop nmbd
ifdown eth0
systemctl start nmbd

It seems that nmbd hangs indefinitely waiting on a network interface, even if the loopback interface is up.

I think this is a bug because laptop users may have samba installed but don't always have a network available (apart from loopback).

[Robie Basak (racb)]

This reproduces on sid, so I forwarded this report to Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=842056

[Launchpad Janitor (janitor)]

This bug was fixed in the package samba - 2:4.5.4+dfsg-1ubuntu1

---------------
samba (2:4.5.4+dfsg-1ubuntu1) zesty; urgency=medium

  * Merge from Debian unstable (LP: #1659707, LP: #1639962). Remaining
    changes:
    + debian/VERSION.patch: Update vendor string to "Ubuntu".
    + debian/smb.conf;
      - Add "(Samba, Ubuntu)" to server string.
      - Comment out the default [homes] share, and add a comment about "valid users = %s"
         to show users how to restrict access to \\server\username to only username.
    + debian/samba-common.config:
      - Do not change prioritiy to high if dhclient3 is installed.
    + Add apport hook:
      - Created debian/source_samba.py.
      - debian/rules, debia/samb-common-bin.install: install hook.
    + d/p/krb_zero_cursor.patch - apply proposed-upstream fix for
      pam_winbind krb5_ccache_type=FILE failure (LP #1310919)
    + debian/patches/winbind_trusted_domains.patch: make sure domain members
      can talk to trusted domains DCs.
      [ update patch based upon upstream discussion ]
    + d/p/fix-1584485.patch: Make libnss-winbind and libpam-winbind
      to be statically linked fixes LP #1584485.
    + d/rules: Compile winbindd/winbindd statically.
  * Drop:
    - Delete debian/.gitignore
    [ Previously undocumented ]
    - debian/patches/git_smbclient_cpu.patch:
      + backport upstream patch to fix smbclient users hanging/eating cpu on
        trying to contact a machine which is not there (lp #1572260)
    [ Fixed upstream ]
    - SECURITY UPDATE: remote code execution via heap overflow in NDR parsing
      + debian/patches/CVE-2016-2123.patch: check lengths in
        librpc/ndr/ndr_dnsp.c.
      + CVE-2016-2123
    [ Fixed in Debian ]
    - SECURITY UPDATE: unconditional privilege delegation to Kerberos servers
      + debian/patches/CVE-2016-2125.patch: don't use GSS_C_DELEG_FLAG in
        source4/scripting/bin/nsupdate-gss, source3/librpc/crypto/gse.c,
        source4/auth/gensec/gensec_gssapi.c.
      + CVE-2016-2125
    [ Fixed in Debian ]
    - SECURITY UPDATE: privilege elevation in Kerberos PAC validation
      + debian/patches/CVE-2016-2126.patch: only allow known checksum types
        in auth/kerberos/kerberos_pac.c.
      + CVE-2016-2126
    [ Fixed in Debian ]

 -- Nishanth Aravamudan <email address hidden> Thu, 26 Jan 2017 17:20:15 -0800

[Andreas Hasenack (ahasenack)]

I filed an upstream bug about this, since we are still seeing it happen in the wild. I think the real fix should be for nmbd to notify systemd as soon as it's up and running, instead of when an interface is available. Because nmbd already has a loop where it waits forever for an interface even after it started up, i.e., it dynamically adapts itself.

https://bugzilla.samba.org/show_bug.cgi?id=13111

[Andreas Hasenack (ahasenack)]

I removed the samba task and I'm using a new bug in Ubuntu to track this issue: https://bugs.launchpad.net/ubuntu/+source/samba/+bug/1731502