Ensure that chronyd is running under chrony user account

An XCCDF Rule

Description

chrony is a daemon which implements the Network Time Protocol (NTP). It is designed to synchronize system clocks across a variety of systems and use a source that is highly accurate. More information on chrony can be found at http://chrony.tuxfamily.org/. Chrony can be configured to be a client and/or a server. To ensure that chronyd is running under chrony user account, user variable in /etc/chrony/chrony.conf is set to _chrony or is absent:

user _chrony

This recommendation only applies if chrony is in use on the system.

Rationale

If chrony is in use on the system proper configuration is vital to ensuring time synchronization is working properly.

ID: xccdf_org.ssgproject.content_rule_chronyd_run_as_chrony_user
Severity: Medium
References: 2.1.2.2

10.6.3
Updated: about 1 year ago

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { dpkg-query --show --showformat='${db:Status-Status}\n' 'chrony' 2>/dev/null | grep -q installed; }; then

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^user")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "_chrony"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^user\\>" "/etc/chrony/chrony.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^user\\>.*/$escaped_formatted_output/gi" "/etc/chrony/chrony.conf"
else
    if [[ -s "/etc/chrony/chrony.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/chrony/chrony.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/chrony/chrony.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/chrony/chrony.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Ensure that chronyd is running under chrony user account

Description

Rationale

Remediation - Shell Script