Oracle Linux 8 — ol8addon — vulnerability — patch and remediation guide (ELSA-2023-18908)

📖 ~4 min read  •  Source: ELSA advisory ELSA-2023-18908

Related CVEs: CVE-2022-2879 CVE-2022-41720 CVE-2022-41716 CVE-2022-32190 CVE-2022-2880 CVE-2022-41717

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

ol8addon ships data files, not a daemon — nothing on Oracle Linux 8 listens on a socket because it is installed. The exposure lives in whatever reads those files: a font engine parsing glyph tables, a TLS library consulting the trust store, a runtime resolving a zone name. Symptoms are therefore indirect — a renderer or PDF job crashing on a malformed face, certificate validation accepting or rejecting the wrong issuer, timestamps and scheduled work landing an hour out after a rule change. Long-running processes keep the old copy cached until they are restarted. ol8addon is a package of static data — fonts, certificates, timezone rules or documentation — read by other programs, so it has no unit of its own to restart; the restarts that matter belong to its consumers.

Environment & Reproduction

Reproduction targets Oracle Linux 8 running either the Red Hat Compatible Kernel (RHCK) or the Unbreakable Enterprise Kernel (UEK). Confirm release, kernel, and installed package:

cat /etc/oracle-release
uname -r
rpm -q ol8addon
dnf list installed ol8addon
dnf history list --reverse | head -20

Exercise the workload that uses ol8addon while collecting:

sudo needs-restarting -u  # --useronly: restrict to the invoking user's processes (useful on shared/app hosts)
sudo lsof -n +L1  # link count < 1 = file deleted but still open/mmap'd; this is the ground truth after an RPM replaces a .so (package: lsof)
sudo lsof -n +L1 2>/dev/null | awk 'NR>1 {print $1, $2}' | sort -u  # condensed COMMAND + PID list of every process still running old code
journalctl -xe --no-pager | tail -200
tail -200 /var/log/dnf.log
tail -200 /var/log/audit/audit.log

Root Cause Analysis

Root cause is documented in ELSA advisory ELSA-2023-18908. Upstream Red Hat / Oracle Linux maintainers shipped a fix in the corresponding ol8addon errata; running an outdated build leaves the host exposed and may trigger the failure modes described in the advisory. Correlate transaction history with system logs and SELinux audit entries to isolate the originating change:

dnf history list --reverse | head -30
dnf history info $(dnf history list | awk '/ol8addon/ {print $1; exit}')
ausearch -m AVC,USER_AVC -ts today | tail -100
cat /proc/sys/kernel/tainted   # non-zero = kernel modules / out-of-tree drivers loaded

Quick Triage

Run these checks on Oracle Linux 8 to confirm the failure mode and current state of ol8addon:

rpm -q ol8addon                              # installed version
rpm -V ol8addon                              # verify file integrity
dnf updateinfo info --security ol8addon     # any security advisories outstanding
systemctl --failed --no-pager
firewall-cmd --list-all 2>/dev/null || echo 'firewalld not running'
getenforce                                 # SELinux mode
# e.g. httpd pkg/unit match, but bind→named, postgresql-server→postgresql):
dnf repoquery -l ol8addon 2>/dev/null | grep -E '/lib/systemd/system/.*\.(service|socket|timer)$'  # same check WITHOUT installing (EL7/Amazon Linux 2: yum install yum-utils, then: repoquery -l ol8addon)
systemctl show --no-pager -p Type,RemainAfterExit <UNIT>  # Type=oneshot (often paired with a .timer) means a one-shot job, NOT a daemon -- do not 'restart' it, let the timer fire

Step-by-Step Diagnosis

1. List failed units.

   systemctl --failed --no-pager

2. Follow the journal for ol8addon and the system bus.

   journalctl -xe -f --no-pager

3. Check firewall posture (skip if firewalld is masked).

   firewall-cmd --list-all-zones --permanent
   nft list ruleset 2>/dev/null | head -50

4. Surface SELinux denials and translate them to a policy module if needed.

   ausearch -m AVC,USER_AVC -ts today
   ausearch -m AVC -ts today | audit2allow -a -M /tmp/local-fix
   # Inspect /tmp/local-fix.te before applying:
   sudo semodule -i /tmp/local-fix.pp

5. Verify ol8addon integrity and dependency closure.

   dnf check
   rpm -V ol8addon
   rpm -q --requires ol8addon | xargs -r rpm -q --whatprovides | head

6. Correlate findings with /var/log/dnf.log, dnf history and ELSA advisory ELSA-2023-18908 to pin the change that introduced the regression.

Solution – Primary Fix

Apply the corrective dnf transaction referenced by ELSA advisory ELSA-2023-18908, reload affected systemd units, and reconcile firewalld / SELinux state:

sudo dnf clean expire-cache
sudo dnf -y update ol8addon
sudo needs-restarting -s | sort -u  # STEP 1: read the list before acting. dbus.service, systemd-logind.service and PID 1 must NOT be blind-restarted on a live host -- those mean 'reboot'
systemctl --user list-units --type=service --no-pager  # desktop/session and per-user services are a separate manager; restart them with: systemctl --user restart <UNIT>
rpm -q ol8addon                       # confirm new NVR

If the advisory says a reboot is required (kernel, glibc, systemd, openssl):

sudo needs-restarting -r           # reports kernel/init/glibc need
sudo systemctl reboot              # or: sudo shutdown -r now

Solution – Alternative Approaches

If the primary fix is not viable, choose from these alternatives:

• Roll back the offending dnf transaction:

  sudo dnf history list --reverse
  sudo dnf history undo <id>

• Pin ol8addon with the versionlock plugin:

  sudo dnf install -y python3-dnf-plugin-versionlock
  sudo dnf versionlock add ol8addon
  sudo dnf versionlock list | grep ol8addon

• Downgrade to a known-good NVR from the repo cache or vault:

  sudo dnf --showduplicates list ol8addon
  sudo dnf -y downgrade ol8addon-<older-NVR>

• Switch firewalld backend (nftables ↔ iptables) for compatibility:

  sudo sed -i 's/^FirewallBackend=.*/FirewallBackend=iptables/' /etc/firewalld/firewalld.conf
  sudo systemctl restart firewalld

• If SELinux is suspected, switch to permissive briefly, capture denials, and author a custom module before re-enforcing:

  sudo setenforce 0                                    # do NOT leave permissive
  # reproduce the failure
  sudo ausearch -m AVC -ts recent | audit2allow -a -M mylocal
  sudo semodule -i mylocal.pp
  sudo setenforce 1

• Where the advisory has Ksplice coverage, live-patch without reboot (Oracle Linux Premier Support):

  sudo uptrack-show                # current live patches
  sudo uptrack-upgrade -y          # apply all available
  uptrack-uname -r                 # effective kernel after live patching

Verification & Acceptance Criteria

All of these should pass after the fix:

rpm -q ol8addon                                       # shows the expected fixed NVR
dnf updateinfo list --security installed | head    # no security advisories pending for us
firewall-cmd --list-services                        # required services present
getenforce                                          # intended mode (Enforcing/Permissive)

The conditions described in the advisory must no longer be reported for ol8addon across two consecutive runs.

Rollback Plan

Capture state before any change:

rpm -qa > /root/rpm-pre.txt
dnf history list --reverse > /root/dnf-history-pre.txt
# LVM snapshot of the root LV (size to ~10% of root):
sudo lvcreate -L 4G -s -n root_pre_patch /dev/mapper/$(lvs --noheadings -o lv_path | grep -m1 root | xargs basename)

To revert if the patch is bad:

sudo dnf history undo <id>
# Or downgrade just ol8addon to the previous NVR:
sudo dnf -y downgrade ol8addon
# For SELinux module additions:
sudo semodule -r mylocal
# Reboot only if kernel/initramfs/glibc were rolled back:
sudo systemctl reboot

For kernel rollbacks, select the previous entry from the GRUB menu or set it as default with grubby --set-default /boot/vmlinuz-<older>.

Prevention & Hardening

Prevent recurrence on Oracle Linux 8 hosts running ol8addon:

• Enable scheduled security updates via dnf-automatic:

  sudo dnf install -y dnf-automatic
  # Edit /etc/dnf/automatic.conf:
  # upgrade_type = security
  # apply_updates = yes
  sudo systemctl enable --now dnf-automatic.timer

• Subscribe to the Oracle Linux Errata RSS / mailing list at linux.oracle.com/security.

• Mirror through a local yum/dnf repository:

  sudo dnf install -y dnf-utils createrepo_c
  sudo reposync --download-metadata --downloadcomps -p /srv/repos -m --repo=ol8_baseos_latest
  sudo createrepo_c /srv/repos/ol-baseos

• Pin sensitive packages so they cannot be auto-upgraded:

  sudo dnf install -y python3-dnf-plugin-versionlock
  sudo dnf versionlock add ol8addon

• Snapshot the root LV before every upgrade window:

  sudo lvcreate -L 4G -s -n root_pre_$(date +%Y%m%d) /dev/<vg>/<root-lv>

• Monitor file integrity with AIDE:

  sudo dnf install -y aide
  sudo aide --init && sudo mv /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
  sudo aide --check

• Lock down with SELinux audit rules in /etc/audit/rules.d/:

  # /etc/audit/rules.d/90-cp.rules
  -w /etc/passwd  -p wa -k identity
  -w /etc/shadow  -p wa -k identity
  -w /etc/sudoers -p wa -k privilege
  -a always,exit -F arch=b64 -S execve -k exec

• Where licensed, enable Oracle Ksplice for live kernel and userspace patching:

  sudo dnf install -y uptrack ksplice-tools
  sudo uptrack-upgrade -y
  sudo systemctl enable --now uptrack

Related Errors & Cross-Refs

Issues that commonly surface alongside a ol8addon update: dnf transaction lock contention, systemd unit ordering cycles, SELinux AVC bursts, firewalld zone drift, and kernel taint flags. Triage with:

cat /proc/sys/kernel/tainted
systemd-analyze critical-chain
ausearch -m AVC -ts today | tail
firewall-cmd --get-active-zones
dnf history list --reverse | head

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References & Further Reading

Primary reference: ELSA advisory ELSA-2023-18908. Useful manual pages on Oracle Linux 8:

man dnf
man dnf.conf
man systemctl
man journalctl
man firewall-cmd
man semanage
man audit2allow
man grubby

Other resources: Oracle Linux 8 Administrator’s Guide at docs.oracle.com, the upstream Red Hat CVE database at access.redhat.com/security/cve, the Oracle Ksplice known-fixes feed, and /usr/share/doc/ol8addon/ for component-specific notes implicated in ol8addon.