Creation of SNMPv3 user broken (Jammy/22.04)

[Sascha Lucas]

[ Impact ]

When creating a SNMPv3 user, the net-snmp-create-v3-user script fails to write the generated configuration file with the following error:

# net-snmp-create-v3-user -ro -A MD5 -a XXXXXX -x YYYYY -X DES ZZZZZ
adding the following line to /var/lib/snmp/snmpd.conf:
   createUser ZZZZZ MD5 "XXXXXX" DES "YYYYY"
adding the following line to /snmp/snmpd.conf:
   rouser ZZZZZ
touch: cannot touch '/snmp/snmpd.conf': No such file or directory
/usr/bin/net-snmp-create-v3-user: 144: cannot create /snmp/snmpd.conf: Directory nonexistent

[ Test Plan ]

The bug affects Impish and Jammy. One can reproduce it by issuing the following commands:

$ lxc launch ubuntu-daily:jammy net-snmp-bug1969623-jammy
$ lxc shell net-snmp-bug1969623-jammy
# apt update
# apt install -y snmpd
# systemctl stop snmpd
# net-snmp-create-v3-user -ro -A MD5 -a XXXXXX -x YYYYY -X DES ZZZZZ

You can verify that the command errors out with:

adding the following line to /var/lib/snmp/snmpd.conf:
   createUser ZZZZZ MD5 "XXXXXX" DES "YYYYY"
adding the following line to /snmp/snmpd.conf:
   rouser ZZZZZ
touch: cannot touch '/snmp/snmpd.conf': No such file or directory
/usr/bin/net-snmp-create-v3-user: 146: cannot create /snmp/snmpd.conf: Directory nonexistent

When using a fixed version of the package, the command should succeed with:

adding the following line to /var/lib/snmp/snmpd.conf:
   createUser ZZZZZ MD5 "XXXXXX" DES "YYYYY"
adding the following line to /usr/share/snmp/snmpd.conf:
   rouser ZZZZZ

[ Where problems could occur ]

The fix is very trivial and shouldn't cause regressions in existing deployments; the only thing being patched is the net-snmp-create-v3-user script, so in the unlikely case that a regression occurs it should be limited to the script. If the user has made local modifications to /usr/bin/net-snmp-create-v3-user in order to workaround the problem, they will lose those modifications when updating the package.

[ Other Info ]

The same bug has been reported in Debian, but the fix there is a bit different:

https://salsa.debian.org/debian/net-snmp/-/commit/b4281b2fc9b7ae7897a01d8be586711df98abad7

Debian's fix is arguably more correct because SNMPCONFPATH will expand to /etc/snmp/, which is the right directory to place configuration files in. However, since we're dealing with an SRU here, I chose to go with upstream's fix because it keeps the old behaviour of placing the config file inside /var/lib/snmp/. We will likely revisit this decision during the KK cycle.

[ Original Description ]

When creating a SNMPv3 user this error appears:

$ /usr/bin/net-snmp-config --create-snmpv3-user -ro -A MD5 -a XXXXXX -x YYYYY -X DES ZZZZZ
touch: cannot touch '/snmp/snmpd.conf': No such file or directory
/usr/bin/net-snmp-create-v3-user: 146: cannot create /snmp/snmpd.conf: Directory nonexistent

Looking at /usr/bin/net-snmp-create-v3-user line 146, it seems that $outfile references ${datarootdir} in line 139, which is undefined. Further outfile is already defined at line 121.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: snmpd 5.9.1+dfsg-1ubuntu2
ProcVersionSignature: Ubuntu 5.15.0-25.25-generic 5.15.30
Uname: Linux 5.15.0-25-generic x86_64
ApportVersion: 2.20.11-0ubuntu82
Architecture: amd64
CasperMD5CheckResult: pass
Date: Wed Apr 20 13:34:44 2022
InstallationDate: Installed on 2022-04-20 (0 days ago)
InstallationMedia: Ubuntu-Server 22.04 LTS "Jammy Jellyfish" - Beta amd64 (20220330)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: net-snmp
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.snmp.snmpd.conf: [modified]
mtime.conffile..etc.snmp.snmpd.conf: 2022-04-20T12:50:27.596000

[Paride Legovini (paride)]

Hello Sascha and thanks for this bug report. I can reproduce it using LXD containers and the same dummy options from the bug description. This is a regression from Focal and likely from Impish, at least by looking at the version numbers.

== Focal ==

root@paride-f:~# net-snmp-config --create-snmpv3-user -ro -A MD5 -a XXXXXX -x YYYYY -X DES ZZZZZ
adding the following line to /var/lib/snmp/snmpd.conf:
   createUser ZZZZZ MD5 "XXXXXX" DES "YYYYY"
adding the following line to /usr/share/snmp/snmpd.conf:
   rouser ZZZZZ

== Jammy ==

root@paride-j:~# net-snmp-config --create-snmpv3-user -ro -A MD5 -a XXXXXX -x YYYYY -X DES ZZZZZ
adding the following line to /var/lib/snmp/snmpd.conf:
   createUser ZZZZZ MD5 "XXXXXX" DES "YYYYY"
adding the following line to /snmp/snmpd.conf:
   rouser ZZZZZ
touch: cannot touch '/snmp/snmpd.conf': No such file or directory
/usr/bin/net-snmp-create-v3-user: 146: cannot create /snmp/snmpd.conf: Directory nonexistent

[Paride Legovini (paride)]

Maybe there are good reasons to keep them as they are, but looking at the Focal output:

adding the following line to /var/lib/snmp/snmpd.conf:
   createUser ZZZZZ MD5 "XXXXXX" DES "YYYYY"
adding the following line to /usr/share/snmp/snmpd.conf:
   rouser ZZZZZ

those conf file paths do not look right (policy compliant) to me.

[Sergio Durigan Junior (sergiodj)]

This has been reported against the Debian package and is fixed in salsa (pending upload).

I will backport the fix to Jammy and Impish, which is also affected.

[Steve Langasek (vorlon)]

Hello Sascha, or anyone else affected,

Accepted net-snmp into jammy-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/net-snmp/5.9.1+dfsg-1ubuntu2.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-jammy to verification-done-jammy. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-jammy. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Sascha Lucas (sascha-lucas)]

Hi,

I've testet snmpd-5.9.1+dfsg-1ubuntu2.1 from jammy-proposed. Creation of SNMNPv3 user works now.

Thanks, Sascha.

[Launchpad Janitor (janitor)]

This bug was fixed in the package net-snmp - 5.9.1+dfsg-1ubuntu2.1

---------------
net-snmp (5.9.1+dfsg-1ubuntu2.1) jammy; urgency=medium

  * d/p/lp1969623-net-snmp-create-v3-user-Fix-the-snmpd.conf-path.patch:
    Set ${datarootdir} value in net-snmp-create-v3-user and fix
    error when creating user. (LP: #1969623)

 -- Sergio Durigan Junior <email address hidden> Thu, 21 Apr 2022 16:14:05 -0400

[Brian Murray (brian-murray)]

The verification of the Stable Release Update for net-snmp has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Brian Murray (brian-murray)]

Hello Sascha, or anyone else affected,

Accepted net-snmp into impish-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/net-snmp/5.9+dfsg-3ubuntu3.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-impish to verification-done-impish. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-impish. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Sergio Durigan Junior (sergiodj)]

Verifying the bug for Impish.

First, make sure that the bug is reproduceable:

# apt policy snmpd
snmpd:
  Installed: 5.9+dfsg-3ubuntu2
  Candidate: 5.9+dfsg-3ubuntu2
  Version table:
 *** 5.9+dfsg-3ubuntu2 500
        500 http://archive.ubuntu.com/ubuntu impish/main amd64 Packages
        100 /var/lib/dpkg/status

# net-snmp-create-v3-user -ro -A MD5 -a XXXXXX -x YYYYY -X DES ZZZZZ
adding the following line to /var/lib/snmp/snmpd.conf:
   createUser ZZZZZ MD5 "XXXXXX" DES "YYYYY"
adding the following line to /snmp/snmpd.conf:
   rouser ZZZZZ
touch: cannot touch '/snmp/snmpd.conf': No such file or directory
/usr/bin/net-snmp-create-v3-user: 144: cannot create /snmp/snmpd.conf: Directory nonexistent

Now, update the package and verify that the new version fixes the problem:

# apt policy snmpd
snmpd:
  Installed: 5.9+dfsg-3ubuntu3.1
  Candidate: 5.9+dfsg-3ubuntu3.1
  Version table:
 *** 5.9+dfsg-3ubuntu3.1 500
        500 http://archive.ubuntu.com/ubuntu impish-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     5.9+dfsg-3ubuntu2 500
        500 http://archive.ubuntu.com/ubuntu impish/main amd64 Packages

# net-snmp-create-v3-user -ro -A MD5 -a XXXXXX -x YYYYY -X DES ZZZZZ
adding the following line to /var/lib/snmp/snmpd.conf:
   createUser ZZZZZ MD5 "XXXXXX" DES "YYYYY"
adding the following line to /usr/share/snmp/snmpd.conf:
   rouser ZZZZZ

Everything works as expected, therefore the fix is verified.

[Launchpad Janitor (janitor)]

This bug was fixed in the package net-snmp - 5.9+dfsg-3ubuntu3.1

---------------
net-snmp (5.9+dfsg-3ubuntu3.1) impish; urgency=medium

  * d/p/lp1969623-net-snmp-create-v3-user-Fix-the-snmpd.conf-path.patch:
    Set ${datarootdir} value in net-snmp-create-v3-user and fix
    error when creating user. (LP: #1969623)

 -- Sergio Durigan Junior <email address hidden> Thu, 21 Apr 2022 18:55:17 -0400