Thread: FW: Adding Postgres Repository on Red Hat 9 causes SELinux Warnings "SELinux is preventing /usr/bin/gpg from using the dac_override capability"

FW: Adding Postgres Repository on Red Hat 9 causes SELinux Warnings "SELinux is preventing /usr/bin/gpg from using the dac_override capability"

From

Janet Einhorn

Date:

11 February, 20:12:41

Hello Postgres Admin Mailing Group People –

Our email admin says that we do not employ a “mail-back anti-spam system” and I hope that is true because I don’t want to cause you hassle.

I manage many VMs running Red Hat 9 at various levels from 9.2 through 9.5. On many of these VMs, I have followed instructions on the Postgres “Linux downloads (Red Hat family)” page: https://www.postgresql.org/download/linux/redhat/

More specifically, according to the instructions for Version 15, Platform RHEL-9, and architecture x86_64, I ran the following commands:

# Install the repository RPM:

sudo dnf install -y https://download.postgresql.org/pub/repos/yum/reporpms/EL-9-x86_64/pgdg-redhat-repo-latest.noarch.rpm

# Disable the built-in PostgreSQL module:

sudo dnf -qy module disable postgresql

I did not necessarily install any version of Postgres Server. On some of these VMs, I installed only the Postgres-12 client:

# sudo dnf install postgresql12.x86_64

Installation of the Postgres Repository RPM causes the following file, shown here with the security context. I noticed that the security context user is system_u, different from the security context user of the Red Hat repository:

$ sudo ls -lZ /etc/yum.repos.d

total 128

-rw-r--r--. 1 root root system_u:object_r:system_conf_t:s0 13328 Apr 10 2024 pgdg-redhat-all.repo

-rw-------. 1 root root unconfined_u:object_r:system_conf_t:s0 111620 Jan 30 20:54 redhat.repo

I have noticed that as soon as I introduce the Postgres repository, large batches of SELinux warnings start showing up in /var/log/messages every 4 hours. These messages show up in batches of 32 every 4 hours. For example:

[local_jeinhorn@itsdev ~]$ sudo grep setroubleshoot /var/log/messages | egrep "Feb 11 07:28:" | tail -6

Feb 11 07:28:22 itsdev setroubleshoot[159834]: SELinux is preventing /usr/bin/gpg from using the dac_override capability. For complete SELinux messages run: sealert -l 78da067f-bff8-47fb-a13e-e5c398990ed4

Feb 11 07:28:22 itsdev setroubleshoot[159834]: SELinux is preventing /usr/bin/gpg from using the dac_override capability.#012#012***** Plugin dac_override (91.4 confidence) suggests **********************#012#012If you want to help identify if domain needs this access or you have a file with the wrong permissions on your system#012Then turn on full auditing to get path information about the offending file and generate the error again.#012Do#012#012Turn on full auditing#012# auditctl -w /etc/shadow -p w#012Try to recreate AVC. Then execute#012# ausearch -m avc -ts recent#012If you see PATH record check ownership/permissions on file, and fix it,#012otherwise report as a bugzilla.#012#012***** Plugin catchall (9.59 confidence) suggests **************************#012#012If you believe that gpg should have the dac_override capability by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'gpg' --raw | audit2allow -M my-gpg#012# semodule -X 300 -i my-gpg.pp#012

Feb 11 07:28:32 itsdev systemd[1]: setroubleshootd.service: Deactivated successfully.

Feb 11 07:28:32 itsdev systemd[1]: setroubleshootd.service: Consumed 1.016s CPU time.

All the gpgkey file entries in are the same:

[local_jeinhorn@useengatldevdb ~]$ sudo grep gpgkey /etc/yum.repos.d/pgdg-redhat-all.repo

gpgkey=file:///etc/pki/rpm-gpg/PGDG-RPM-GPG-KEY-RHEL

. . . <SNIP LOTS OF THE SAME> . . .

gpgkey=file:///etc/pki/rpm-gpg/PGDG-RPM-GPG-KEY-RHEL

The Postgres repository GPG key stored in /etc/pki/rpm-gpg/PGDG-RPM-GPG-KEY-RHEL has already been imported into RPM:

[local_jeinhorn@useengatldevdb ~]$ sudo tail -5 /etc/pki/rpm-gpg/PGDG-RPM-GPG-KEY-RHEL

RfQX29x8baM4mdKVBmU9KQxRgno6lcks14STnawqf6o9nHxKp80VQrcNTsYHlq2B

PGAanK8G4WeYojQWCQHBi73qCoTERMpBG73gpTIr836TBinGZaSZ8I1deUS89Hnw

A62QO1TS57zxMTrstzaawLoCIHTqyJ2VeZrVC1INV4ENnyVsud3NaZtfWuIk7Q==

=Elfg

[local_jeinhorn@useengatldevdb ~]$ sudo rpm -qa gpg*

gpgme-1.15.1-6.el9.x86_64

gpg-pubkey-fd431d51-4ae0493b

gpg-pubkey-5a6340b3-6229229e

gpg-pubkey-08b40d20-6581afc1

[local_jeinhorn@useengatldevdb ~]$ sudo rpm -qi gpg-pubkey-08b40d20-6581afc1

Name : gpg-pubkey

Version : 08b40d20

Release : 6581afc1

Architecture: (none)

Install Date: Thu 29 Feb 2024 04:08:50 PM EST

Group : Public Keys

Size : 0

License : pubkey

Signature : (none)

Source RPM : (none)

Build Date : Tue 19 Dec 2023 09:59:13 AM EST

Build Host : localhost

Packager : PostgreSQL RPM Repository <pgsql-pkg-yum@lists.postgresql.org>

Summary : PostgreSQL RPM Repository <pgsql-pkg-yum@lists.postgresql.org> public key

Description :

-----BEGIN PGP PUBLIC KEY BLOCK-----

Version: rpm-4.16.1.3 (NSS-3)

mQGNBGWBr8EBDAC+atC3Hl2yKkFg0F4tDg4ABCTvvhgMn7g7oZ0vJqpaUAwUgijU

+jLXH8qVSkyhk2eruSXlbj4dIMHhsbRQ1wUnd+tb8pZPdRaBFR9MzFMjvDzobAlZ

. . . <SNIP> . . .

PGAanK8G4WeYojQWCQHBi73qCoTERMpBG73gpTIr836TBinGZaSZ8I1deUS89Hnw

A62QO1TS57zxMTrstzaawLoCIHTqyJ2VeZrVC1INV4ENnyVsud3NaZtfWuIk7Q==

=Elfg

-----END PGP PUBLIC KEY BLOCK-----

The only way I was able to stop these messages was to update /etc/dnf/dnf.conf and /etc/yum.repos.d/pgdg-redhat-all.repo and disable the gpg checking in all instances (change gpgcheck from 1 to 0 and change repo_gpgcheck from 1 to 0).

I’m sure this is not the optimal way to avoid /var/log/messages getting spammed with setroubleshoot entries, but I don’t know what needs to be done! I am amazed this issue has not been reported by others.

Do you have advice on what I need to do, to stop the SELinux messages from getting logged into /var/log/messages?

Many Thanks,

Janet Einhorn

System Administrator

KNS FTW I.T. Infrastructure Team

215-784-6171

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