Runelab CA

A certificate authority for the HomeLab.

The setup was mostly done by following these two guides:

• Jamie Nguyen's OpenSSL CA guide
• Mour's blog post Jamie's guide using an HSM

Notes of precaution

• The root key is a yubikey kept in a physical vault at a bank in Switzerland.

Setup

Required Software

• OpenSSL
• libp11
• YKCS11
  • AUR Link

macOS note: openssl installed via homebrew does not pickup on libp11, you need to manually copy the pkcs11 library (update the versions):

cp /opt/homebrew/Cellar/libp11/0.4.12/lib/engines-3/pkcs11.dylib /opt/homebrew/Cellar/openssl@3/3.2.1/lib/engines-3/

Environment Variables

These must be set for all openssl operations.

Linux:

• PKCS11_MODULE_PATH="/usr/lib/libykcs11.so"

macOS:

• PKCS11_MODULE_PATH="/opt/homebrew/lib/libykcs11.dylib"

Setting up a new yubikey

The signing key on a yubikey is stored in slot 9a. On a new yubikey this slot is empty.

To generate a new key, run the following command: yubico-piv-tool -a generate -s 9a -A ECCP384

Generating the Root

# Creating directory structure
mkdir {certs,crl,csr,newcerts,conf}
# Creating required files
touch database.txt
echo 1000 > serial
echo 1000 > crlnumber
# OpenSSL CA config file
vim config/ca.conf
# Generating the root
openssl req -new -x509 -days 8000 -sha256 -extensions v3_ca -engine pkcs11 -keyform engine -key "pkcs11:object=Private key for PIV Authentication" -out certs/root.ca.cert.pem

Issuing Intermediaries

# Sign the Intermediary
openssl ca -config config/ca.conf -engine pkcs11 -keyform engine -keyfile "pkcs11:object=Private key for PIV Authentication" -extensions v3_intermediate_ca -days 1095 -notext -md sha256 -in csr/foobar.int.csr -out certs/foobar.int.cert.pem
# Add the CA to create a chain
echo certs/root.ca.cert.pem >> certs/foobar.int.cert.pem

Certificate Revocation List

Distribution point configured in under server_cert > crlDistributionPoints

This must be reissued every 180 days

# Revoke the certificate
openssl ca -config config/ca.conf -revoke certs/foobar.int.cert.pem
# Create the CRL file
openssl ca -config config/ca.conf -gencrl -out crl/ca.crl.pem -engine pkcs11 -keyform engine -keyfile "pkcs11:object=Private key for PIV Authentication"