Import DoD root certificates into linux CA store

add-dod-certs.sh

#!/bin/bash
# Imports DoD root certificates into Linux CA store
# Version 0.4.2 updated 20250425 by AfroThundr
# SPDX-License-Identifier: GPL-3.0-or-later

# For issues or updated versions of this script, browse to the following URL:
# https://gist.github.com/AfroThundr3007730/ba99753dda66fc4abaf30fb5c0e5d012

# Dependencies: curl gawk openssl unzip wget

set -euo pipefail
shopt -s extdebug nullglob

add_dod_certs() {
    local bundle cert certdir file form tmpdir url update
    trap '[[ -d ${tmpdir:-} ]] && rm -fr $tmpdir' EXIT INT TERM

    # Location of bundle from DISA site
    url='https://public.cyber.mil/pki-pke/pkipke-document-library/'
    bundle=$(curl -s $url | awk -F '"' 'tolower($2) ~ /dod.zip/ {print $2}')

    # Set cert directory and update command based on OS
    [[ -f /etc/os-release ]] && source /etc/os-release
    if [[ ${ID:-} =~ (fedora|rhel|centos) ||
        ${ID_LIKE:-} =~ (fedora|rhel|centos) ]]; then
        certdir=/etc/pki/ca-trust/source/anchors
        update='update-ca-trust'
    elif [[ ${ID:-} =~ (debian|ubuntu|mint) ||
        ${ID_LIKE:-} =~ (debian|ubuntu|mint) ]]; then
        certdir=/usr/local/share/ca-certificates
        update='update-ca-certificates'
    else
        certdir=${1:-} && update=${2:-}
    fi

    [[ ${certdir:-} && ${update:-} ]] || {
        printf 'Unable to autodetect OS using /etc/os-release.\n'
        printf 'Please provide CA certificate directory and update command.\n'
        printf 'Example: %s /cert/store/location update-cmd\n' "${0##*/}"
        exit 1
    }

    # Extract the bundle
    wget -qP "${tmpdir:=$(mktemp -d)}" "$bundle"
    unzip -qj "$tmpdir"/"${bundle##*/}" -d "$tmpdir"

    # Check for existence of PEM or DER format p7b.
    for file in "$tmpdir"/*_{DoD,dod}{.,_}{pem,der}.p7b; do
        # Iterate over glob instead of testing directly (SC2144)
        [[ -f ${file:-} ]] && 
            form=${file%.*} && form=${form##*_} && form=${form##*.} && break
    done
    [[ ${form:-} && ${file:-} ]] || { printf 'No bundles found!\n' && exit 1; }

    # Convert the PKCS#7 bundle into individual PEM files
    openssl pkcs7 -print_certs -inform "$form" -in "$file" |
        awk -v d="$tmpdir" \
            'BEGIN {c=0} /subject=/ {c++} {print > d "/cert." c ".pem"}'

    # Rename the files based on the CA name
    for cert in "$tmpdir"/cert.*.pem; do
        mv "$cert" "$certdir"/"$(
            openssl x509 -noout -subject -in "$cert" |
                awk -F '(=|= )' '{print gensub(/ /, "_", "g", $NF)}'
        )".crt
    done

    # Remove temp files and update certificate stores
    rm -fr "$tmpdir" && $update
}

# Only execute if not being sourced
[[ ${BASH_SOURCE[0]} == "$0" ]] || return 0 && add_dod_certs "$@"

I've implemented add-dod-certs.sh in an Ansible playbook for Fedora/RHEL systems. It can be easily extended to support Ubuntu/Debian systems. Credit to AfroThundr for the original bash script that guided this.

# vim: ft=yaml.ansible
# ensure community.crypto collection is installed on control node
---
- name: Install DoD certificates system-wide
  connection: local
  hosts: 127.0.0.1
  become: true
  vars:
    dod_certs_url: "https://dl.dod.cyber.mil/wp-content/uploads/pki-pke/zip/unclass-certificates_pkcs7_DoD.zip"
    system_cert_dir: "/etc/pki/ca-trust/source/anchors"

  tasks:
    - name: Extract DoD certs zip
      ansible.builtin.unarchive:
        src: "{{ dod_certs_url }}"
        dest: "/tmp"
        list_files: true
        remote_src: true
      register: certs

    - name: Locate DoD PKCS#7 cert bundle
      ansible.builtin.set_fact:
        pkcs7_bundle_path: >-
          {{ "/tmp/" + (certs.files
          | select('match', '.*(?i:dod)\.pem\.p7b$')
          | first) }}

    - name: Extract certificates from PKCS#7 bundle
      ansible.builtin.command: >
        openssl pkcs7 -print_certs -inform PEM -in {{ pkcs7_bundle_path }}
      register: pkcs7_bundle_output
      changed_when: false

    - name: Split certs into individual PEMs
      ansible.builtin.set_fact:
        cert_list: "{{ pkcs7_bundle_output.stdout | community.crypto.split_pem }}"

    - name: Get cert info
      community.crypto.x509_certificate_info:
        content: "{{ item }}"
      loop: "{{ cert_list }}"
      register: cert_info

    - name: Build cert data structure
      ansible.builtin.set_fact:
        cert_data: >-
          {{ cert_data | default([]) + [
              {
                'content': item.0,
                'file_name': (item.1.subject.commonName
                    | replace(' ', '_')
                    | regex_replace('$', '.crt'))
              }
            ]
          }}
      loop: "{{ cert_list | zip(cert_info.results) | list }}"

    - name: Install certs to system trust store
      ansible.builtin.copy:
        content: "{{ item.content }}"
        dest: "{{ system_cert_dir }}/{{ item.file_name }}"
        mode: '0644'
        owner: root
        group: root
      loop: "{{ cert_data }}"
      register: cert_installation

    - name: Update CA trust
      ansible.builtin.command: update-ca-trust
      changed_when: cert_installation.changed
      when: cert_installation.changed

edit: improved the pkcs7 bundle regex