samba update to version 2:4.15.13+dfsg-0ubuntu0.20.04.1 on 3/8 causes nmbd to spam errors to logfile

[Bill Miller]

On 3/8/23 I got the following updates through the normal process:

Start-Date: 2023-03-08 15:26:44
Commandline: /usr/sbin/synaptic
Requested-By: bill (1000)
Upgrade: libldb2:amd64 (2:2.2.3-0ubuntu0.20.04.3, 2:2.4.4-0ubuntu0.20.04.1), gvfs-backends:amd64 (1.44.1-1ubuntu1.1, 1.44.1-1ubuntu1.2), libwbclient0:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), python3-ldb:amd64 (2:2.2.3-0ubuntu0.20.04.3, 2:2.4.4-0ubuntu0.20.04.1), samba:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), samba-dsdb-modules:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), tdb-tools:amd64 (1.4.3-0ubuntu0.20.04.1, 1.4.5-0ubuntu0.20.04.1), python3-tdb:amd64 (1.4.3-0ubuntu0.20.04.1, 1.4.5-0ubuntu0.20.04.1), libtalloc2:amd64 (2.3.1-0ubuntu0.20.04.1, 2.3.3-0ubuntu0.20.04.1), samba-libs:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), gvfs-libs:amd64 (1.44.1-1ubuntu1.1, 1.44.1-1ubuntu1.2), gvfs-fuse:amd64 (1.44.1-1ubuntu1.1, 1.44.1-1ubuntu1.2), python3-samba:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), samba-common:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), samba-vfs-modules:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), libsmbclient:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), smbclient:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), samba-common-bin:amd64 (2:4.13.17~dfsg-0ubuntu1.20.04.5, 2:4.15.13+dfsg-0ubuntu0.20.04.1), libtdb1:amd64 (1.4.3-0ubuntu0.20.04.1, 1.4.5-0ubuntu0.20.04.1), python3-talloc:amd64 (2.3.1-0ubuntu0.20.04.1, 2.3.3-0ubuntu0.20.04.1), gvfs:amd64 (1.44.1-1ubuntu1.1, 1.44.1-1ubuntu1.2), gvfs-common:amd64 (1.44.1-1ubuntu1.1, 1.44.1-1ubuntu1.2), libtevent0:amd64 (0.10.2-0ubuntu0.20.04.1, 0.11.0-0ubuntu0.20.04.1), gvfs-daemons:amd64 (1.44.1-1ubuntu1.1, 1.44.1-1ubuntu1.2)
End-Date: 2023-03-08 15:27:49

Immediately after incorporating these updates, samba restarted, and ever since, I have received 60-70 errors like the ones below in the log every day. samba was running for years before this with no errors in the log.

  Samba name server ST8 is now a local master browser for workgroup WORKGROUP on subnet 192.168.1.2

  *****
[2023/03/08 15:37:54.989258, 0] ../../source3/nmbd/nmbd_nameregister.c:73(register_name_response)
  register_name_response: Answer name <00> differs from question name <00>.
[2023/03/08 15:37:54.989783, 0] ../../source3/nmbd/nmbd_nameregister.c:73(register_name_response)
  register_name_response: Answer name <03> differs from question name <03>.
[2023/03/08 15:37:54.990062, 0] ../../source3/nmbd/nmbd_nameregister.c:73(register_name_response)
  register_name_response: Answer name <20> differs from question name <20>.
[2023/03/08 15:58:11.749576, 0] ../../source3/nmbd/nmbd_nameregister.c:73(register_name_response)
  register_name_response: Answer name <00> differs from question name <00>.
[2023/03/08 15:58:11.753057, 0] ../../source3/nmbd/nmbd_nameregister.c:73(register_name_response)
  register_name_response: Answer name <03> differs from question name <03>.
[2023/03/08 15:58:11.754677, 0] ../../source3/nmbd/nmbd_nameregister.c:73(register_name_response)
  register_name_response: Answer name <20> differs from question name <20>.
[2023/03/08 16:18:31.830354, 0] ../../source3/nmbd/nmbd_nameregister.c:73(register_name_response)
  register_name_response: Answer name <00> differs from question name <00>.

I have not been able to google any information about this "answer differs from question" error.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: samba 2:4.15.13+dfsg-0ubuntu0.20.04.1
ProcVersionSignature: Ubuntu 5.15.0-67.74~20.04.1-generic 5.15.85
Uname: Linux 5.15.0-67-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.25
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: MATE
Date: Tue Mar 14 08:25:11 2023
InstallationDate: Installed on 2016-08-27 (2390 days ago)
InstallationMedia: Lubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160720)
OtherFailedConnect: Yes
SambaServerRegression: Yes
SmbConfIncluded: No
SourcePackage: samba
TestparmExitCode: 0
UpgradeStatus: Upgraded to focal on 2021-10-24 (505 days ago)
modified.conffile..etc.default.apport: [modified]
mtime.conffile..etc.default.apport: 2018-09-05T10:01:35.193624

[Athos Ribeiro (athos-ribeiro)]

Hi Bill,

Could you provide a minimal reproducer for the issue so we can dig this one up?

Moreover, is the only unexpected behavior you are experiencing is this message being pushed to your error logs or are you actually experiencing any functional issues?

[Bill Miller (wbmilleriii)]

Athos Riberio,

Thanks for your attention to this issue.

I literally didn't do ANYTHING to cause the issue other than install the update. That caused samba to restart, and start spewing the errors, as stated in the bug report.

So, to reproduce

1) Prior to installing the update, check the /var/log/samba/log.nmbd and confirm that the subject errors are not present
2) Install the subject update
3) Check the /var/log/samba/log.nmbd and confirm that the subject errors are present

As far as I know, there is no ill effect other than the log-spamming. But since I have been unable to find any information about what the error means, I do not know what the impact is.

[Paride Legovini (paride)]

Hi,

I tried to setup an (extremely simple) reproducer and I didn't get the log spam. I tried by directly installing the samba package from focal-security (2:4.15.13+dfsg-0ubuntu0.20.04.1), as I think it's unlikely that an *upgrade* is required to trigger the issue.

With the information we have it is difficult to differentiate between a bug in Ubuntu and a local issue (e.g. a misbehaving network client). We need something like a full reproducer for that: a minimal set of steps that actually brings to the log spam.

We know that the behavior of packages in Ubuntu stable release shouldn't change, and we strive to achieve that when fixing bugs (see [1]). However there are cases that are not clear cut, and to address security issues in samba a new upstream version has been released to Focal (4.15.13 -> 4.13.17). This new version may have become more picky or verbose in some cases.

[1] https://wiki.ubuntu.com/StableReleaseUpdates

[Launchpad Janitor (janitor)]

[Expired for samba (Ubuntu) because there has been no activity for 60 days.]