constellation/image/secure-boot/genkeys.sh

#!/usr/bin/env bash
# Copyright (c) Edgeless Systems GmbH
#
# SPDX-License-Identifier: AGPL-3.0-only

# This script generates a PKI for secure boot.
# It is based on the example from https://github.com/systemd/systemd/blob/main/man/loader.conf.xml
# This is meant to be used for development purposes only.
# Release images are signed using a different set of keys.
# Set PKI to an empty folder and PKI_SET to "dev".

set -euo pipefail
shopt -s inherit_errexit

script_dir=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &> /dev/null && pwd)
templates=${script_dir}/templates
base_dir=$(realpath "${script_dir}/..")
pki="${PKI:-${base_dir}/pki}"
pki_set="${PKI_SET:-dev}"

gen_pki() {
  # Only use for non-production images.
  # Use real PKI for production images instead.
  mkdir -p "${pki}"
  count=$(find "${pki}" -maxdepth 1 \( -name '*.key' -o -name '*.crt' -o -name '*.cer' -o -name '*.esl' -o -name '*.auth' \) 2> /dev/null | wc -l)
  if [[ ${count} != 0 ]]; then
    echo PKI files "$(ls -1 "$(realpath "--relative-to=$(pwd)" "${pki}")"/*.{key,crt,cer,esl,auth})" already exist
    return
  fi
  pushd "${pki}" || exit 1

  uuid=$(systemd-id128 new --uuid)
  for key in PK KEK db; do
    openssl req -new -x509 -config "${templates}/${pki_set}_${key}.conf" -keyout "${key}.key" -out "${key}.crt" -nodes
    openssl x509 -outform DER -in "${key}.crt" -out "${key}.cer"
    cert-to-efi-sig-list -g "${uuid}" "${key}.crt" "${key}.esl"
  done

  for key in MicWinProPCA2011_2011-10-19.crt MicCorUEFCA2011_2011-06-27.crt MicCorKEKCA2011_2011-06-24.crt; do
    curl -fsSL "https://www.microsoft.com/pkiops/certs/${key}" --output "${key}"
    sbsiglist --owner 77fa9abd-0359-4d32-bd60-28f4e78f784b --type x509 --output "${key%crt}esl" "${key}"
  done

  # Optionally add Microsoft Windows Production CA 2011 (needed to boot into Windows).
  cat MicWinProPCA2011_2011-10-19.esl >> db.esl

  # Optionally add Microsoft Corporation UEFI CA 2011 (for firmware drivers / option ROMs
  # and third-party boot loaders (including shim). This is highly recommended on real
  # hardware as not including this may soft-brick your device (see next paragraph).
  cat MicCorUEFCA2011_2011-06-27.esl >> db.esl

  # Optionally add Microsoft Corporation KEK CA 2011. Recommended if either of the
  # Microsoft keys is used as the official UEFI revocation database is signed with this
  # key. The revocation database can be updated with [fwupdmgr(1)](https://www.freedesktop.org/software/systemd/man/fwupdmgr.html#).
  cat MicCorKEKCA2011_2011-06-24.esl >> KEK.esl

  sign-efi-sig-list -c PK.crt -k PK.key PK PK.esl PK.auth
  sign-efi-sig-list -c PK.crt -k PK.key KEK KEK.esl KEK.auth
  sign-efi-sig-list -c KEK.crt -k KEK.key db db.esl db.auth

  popd || exit 1
}

# gen_pki generates a PKI for testing purposes only.
# if keys/certs are already present in the pki folder, they are not regenerated.
gen_pki