packer-hcloud/scripts/20-rocky-9.sh

#!/bin/bash
set -eo pipefail

### Updates system
echo '> Update packages ...'
dnf -yq update
dnf -q clean all

## Sets Grub config
echo '> Set grub config ...'
KERNEL_OPTIONS=(
    'audit=1'
    'audit_backlog_limit=8192'
)
sed -i -e \
    "s/.*GRUB_CMDLINE_LINUX=\"\(.*\)\"/GRUB_CMDLINE_LINUX=\"\1 ${KERNEL_OPTIONS[*]}\"/" \
    /etc/default/grub

# Remove any repeated (de-duplicate) Kernel options.
OPTIONS=$(sed -e \
    "s/GRUB_CMDLINE_LINUX=\"\(.*\)\"/GRUB_CMDLINE_LINUX=\"\1 ${KERNEL_OPTIONS[*]}\"/" \
    /etc/default/grub |
    grep -E '^GRUB_CMDLINE_LINUX=' |
    sed -e 's/GRUB_CMDLINE_LINUX=\"\(.*\)\"/\1/' |
    tr ' ' '\n' | sort -u | tr '\n' ' ' | xargs)

sed -i -e \
    "s@GRUB_CMDLINE_LINUX=\"\(.*\)\"@GRUB_CMDLINE_LINUX=\"${OPTIONS}\"@" \
    /etc/default/grub

grubby --update-kernel=ALL --args="audit=1"
grubby --update-kernel=ALL --args="audit_backlog_limit=8192"
chmod 600 /boot/grub2/grub.cfg

### Sets cron permissions
echo '> Set cron permissions ...'
chmod 0700 /etc/cron.d
chmod 0700 /etc/cron.daily
chmod 0700 /etc/cron.hourly
chmod 0700 /etc/cron.monthly
chmod 0700 /etc/cron.weekly
chmod 0600 /etc/crontab
rm -rf /etc/cron.deny

### Cleans all audit logs
echo '> Cleaning all audit logs ...'
if [ -f /var/log/audit/audit.log ]; then
    cat /dev/null >/var/log/audit/audit.log
fi

if [ -f /var/log/wtmp ]; then
    cat /dev/null >/var/log/wtmp
fi

if [ -f /var/log/lastlog ]; then
    cat /dev/null >/var/log/lastlog
fi

### Cleans persistent udev rules
echo '> Cleaning persistent udev rules ...'
if [ -f /etc/udev/rules.d/70-persistent-net.rules ]; then
    rm /etc/udev/rules.d/70-persistent-net.rules
fi

### Clean the /tmp directories
echo '> Cleaning /tmp directories ...'
rm -rf /tmp/*
rm -rf /var/tmp/*
rm -rf /var/cache/dnf/*

### Clean the SSH keys
echo '> Cleaning the SSH keys ...'
shred -u /etc/ssh/*_key /etc/ssh/*_key.pub
rm -f /etc/ssh/ssh_config.d/allow-root-ssh.conf
rm -rf /root/.ssh/authorized_keys

### Clean the machine-id
echo '> Cleaning the machine-id ...'
truncate -s 0 /etc/machine-id
rm -f /var/lib/dbus/machine-id
mkdir -p /var/lib/dbus
ln -s /etc/machine-id /var/lib/dbus/machine-id

### Prepare cloud-init
echo '> Preparing cloud-init ...'
rm -f /etc/cloud/cloud-init.disabled

### Clean the shell history
echo '> Cleaning the shell history ...'
unset HISTFILE
history -cw
echo >~/.bash_history
rm -f /root/.bash_history

### Done
echo '> Done.'