Configure file name of core dumps

An XCCDF Rule

Description

To set the runtime status of the kernel.core_uses_pid kernel parameter, run the following command:

$ sudo sysctl -w kernel.core_uses_pid=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

kernel.core_uses_pid = 0

Rationale

The default coredump filename is core. By setting core_uses_pid to 1, the coredump filename becomes core.PID. If core_pattern does not include %p (default does not) and core_uses_pid is set, then .PID will be appended to the filename. When combined with kernel.core_pattern = "" configuration, it is ensured that no core dumps are generated and also no confusing error messages are printed by a shell.

ID: xccdf_org.ssgproject.content_rule_sysctl_kernel_core_uses_pid
Severity: Medium
References: FMT_SMF_EXT.1
Updated: 5 days ago

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - disable_strategy
  - low_complexity  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_kernel_core_uses_pid

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*kernel.core_uses_pid.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_kernel_core_uses_pid

- name: Comment out any occurrences of kernel.core_uses_pid from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*kernel.core_uses_pid
    replace: '#kernel.core_uses_pid'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_kernel_core_uses_pid

- name: Ensure sysctl kernel.core_uses_pid is set to 0
  sysctl:
    name: kernel.core_uses_pid
    value: '0'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_kernel_core_uses_pid

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of kernel.core_uses_pid from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do

  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*kernel.core_uses_pid.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "kernel.core_uses_pid" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"


#
# Set runtime for kernel.core_uses_pid
#
/sbin/sysctl -q -n -w kernel.core_uses_pid="0"

#
# If kernel.core_uses_pid present in /etc/sysctl.conf, change value to "0"
#	else, add "kernel.core_uses_pid = 0" to /etc/sysctl.conf
#

# 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' <<< "^kernel.core_uses_pid")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"

# 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 "^kernel.core_uses_pid\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^kernel.core_uses_pid\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

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

Configure file name of core dumps

Description

Rationale

Remediation - Ansible

Remediation - Shell Script