The Lost Art of the Makefile

This repository uses OpenSSL and GNU Makefile to automate and simplify Certificate Signing Request (CSR) processes.

Problem

Creating replicas of TLS certificates for testing and development can be time-consuming and complex. This includes generating CA authority certificates, Signing Authority certificates, and certificates with complex Subject Alternative Names (SANs) for mTLS.

Corporate CSR processes can take anywhere from hours to weeks to complete. Having pre-tested Certificate Signing Requests (CSRs) ready can significantly streamline this process.

Example of a Complex Subject Alternative Name for mTLS Certificate

X509v3 extensions:
    X509v3 Key Usage: critical
        Digital Signature, Key Encipherment
    X509v3 Basic Constraints: 
        CA:FALSE
    X509v3 Extended Key Usage: 
        TLS Web Server Authentication, TLS Web Client Authentication, Code Signing, E-mail Protection
    X509v3 Subject Key Identifier: 
        F0:76:3B:B0:03:20:C5:15:2F:7A:4E:F1:F6:FE:AE:06:31:FE:88:B9
    X509v3 Authority Key Identifier: 
        E1:7D:A3:BE:51:DF:F9:1E:29:80:C8:57:CC:D9:D6:3E:37:5D:5F:55
    X509v3 Subject Alternative Name: 
        DNS:vault.dev1.gcp.lab5.ca, DNS:vault.prd1.gcp.lab5.ca, DNS:vault-0, DNS:vault-1, DNS:vault-2, DNS:vault, DNS:vault.vault, DNS:vault.vault.svc, DNS:vault.vault.svc.cluster, DNS:vault.vault.svc.cluster.local, DNS:vault-0.cluster, DNS:vault-1.cluster, DNS:vault-2.cluster, IP Address:127.0.0.1

Solution

This repository allows you to test your Subject Alternative Names (SANs) and deployment process using a test certificate before submitting a CSR to the corporate PKI.

Efficient Certificate Generation with GNU Make

GNU Make offers a powerful feature that optimizes the certificate generation process. By leveraging timestamp comparisons, it allows us to skip the generation of certificates when the source files haven't changed. This capability enables us to create an efficient dependency chain, streamlining the entire PKI management workflow.

root_crt ==> signing_crt ==> host_crt

Demo

Creating Certificate Authority Certificates

create-ca-authority.mp4

Creating Host Certificate Bundle

create-certificate.mp4

Requirements

• OpenSSL version 3.0.0 or higher (https://www.openssl.org/)
• GNU Make 4.0.0 or higher (https://www.gnu.org/software/make/)
• GNU PG 2.0.0 or higher (https://gnupg.org/)

Project Structure

The project is organized as follows:

• Core Logic: The main functionality is implemented in the Makefile.
• OpenSSL: The repository follows the standard OpenSSL directory structure.

Key Components

• makefile contains the core logic and automation scripts.
• ca directory stores Certificate Authority related files.
• etc directory stores OpenSSL configuration files.
• certs directory stores generated certificates.

Generated Certificate Package

The repository generates a comprehensive certificate package containing:

• Root CA certificate chain (Root+Signing) ca-certificates.crt
• Host CSR host.domain.com.csr
• Host certificate host.domain.com.crt
• Host encrypted private key host.domain.com.key
• Host P12 (PFX) bundle host.domain.com.p12

Usage Guide

Setting Up a New PKI

Clone the repository

git clone https://github.com/kborovik/pki-db.git

Initialize new PKI DB (removes old PKI DB and all TLS certificates)

make clean

Remove old Git repository

rm -rf .git

Create new Git repository

git init
git add --all
git commit -m 'initial pki db'

Configuring GPG Keys

GPG keys are used to encrypt passwords for TLS certificate private keys. Each TLS private key receives a unique password, allowing for the generation of random private key passwords that can be easily shared with team members.

Update Makefile with GPG key

sed -i 's/^GPG_KEY .\*/GPG_KEY ?= 1A4A6FC0BB90A4B5F2A11031E577D405DD6ABEA5/' makefile

Verify GPG key

make
==> Certificate <==
COMMON_NAME:
SUBJECT_ALT_NAME:
==> Encryption Key <==
GPG_KEY: 1A4A6FC0BB90A4B5F2A11031E577D405DD6ABEA5
==> Software <==
OpenSSL: OpenSSL 3.0.13 30 Jan 2024 (Library: OpenSSL 3.0.13 30 Jan 2024)
Make: GNU Make 4.3
GPG: gpg (GnuPG) 2.4.4
Create Certificates? (yes/no): 

Updating Certificate Authority Distinguished Name

etc/
├── root.conf
├── signing.conf
└── server.conf

Example configuration

vim etc/root.config
vim etc/signing.config
vim etc/server.config

Update ca_dn

[ ca_dn ]
0.domainComponent = ca
1.domainComponent = lab5
organizationName = Lab5 DevOps Inc.
organizationalUnitName = www.lab5.ca
commonName = $organizationName Root CA

Creating Certificates

To generate a new certificate, follow these steps:

• Set the required COMMON_NAME environment variable.
• Optionally, set the SUBJECT_ALT_NAME environment variable for additional identities.
• Run make command

export COMMON_NAME="www.lab5.ca"
export SUBJECT_ALT_NAME="DNS:www.lab5.ca,IP:127.0.0.1"
make
==> Certificate <==
COMMON_NAME: www.lab5.ca
SUBJECT_ALT_NAME: DNS:www.lab5.ca,IP:127.0.0.1
==> Encryption Key <==
GPG_KEY: 1A4A6FC0BB90A4B5F2A11031E577D405DD6ABEA5
==> Software <==
OpenSSL: OpenSSL 3.0.13 30 Jan 2024 (Library: OpenSSL 3.0.13 30 Jan 2024)
Make: GNU Make 4.3
GPG: gpg (GnuPG) 2.4.4
Create Certificates? (yes/no): 

Managing Certificates

View certificates

tree certs/
certs/
├── ca-certificates.crt
├── db.lab5.ca.asc
├── db.lab5.ca.crt
├── db.lab5.ca.csr
├── db.lab5.ca.key
├── db.lab5.ca.p12
├── www.lab5.ca.asc
├── www.lab5.ca.crt
├── www.lab5.ca.csr
├── www.lab5.ca.key
└── www.lab5.ca.p12

Show Private Key Password

make show-pass

Decrypt Private Key

make show-key

View CSR

make show-csr

View CRT

make show-crt

View P12

make show-p12

Acknowledgements

This repository is based on the excellent work of the "OpenSSL PKI Tutorial".

For more information, visit: https://pki-tutorial.readthedocs.io/en/latest/index.html