Puppet Function: complyadm::generate_cert_chain

Defined in:
lib/puppet/functions/complyadm/generate_cert_chain.rb
Function type:
Ruby 4.x API

Overview

complyadm::generate_cert_chain(String $hostname)Any

Parameters:

  • hostname (String)

Returns:

  • (Any)


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# File 'lib/puppet/functions/complyadm/generate_cert_chain.rb', line 4

Puppet::Functions.create_function(:'complyadm::generate_cert_chain') do
  dispatch :generate do
    param 'String', :hostname
  end

  def generate(hostname)
    ca_key = create_private_key
    ca_cert = create_self_signed_ca(ca_key, "/CN=Comply CA: #{hostname}")
    ca_crl = create_crl_for(ca_cert, ca_key)

    host_key = create_private_key
    host_csr = create_csr(host_key, "/CN=#{hostname}")
    host_cert = sign(hostname, ca_key, ca_cert, host_csr)

    {
      'crl' => ca_crl.to_s,
      'private_key' => host_key.to_s,
      'cert_chain' => "#{host_cert}#{ca_cert}"
    }
  end

  PRIVATE_KEY_LENGTH = 4096
  FIFTEEN_YEARS_SECONDS = 15 * 365 * 24 * 60 * 60

  SSL_SERVER_CERT_OID = '1.3.6.1.5.5.7.3.1'.freeze

  CA_EXTENSIONS = [
    ['basicConstraints', 'CA:TRUE', true],
    ['keyUsage', 'keyCertSign, cRLSign', true],
    ['subjectKeyIdentifier', 'hash', false],
    ['authorityKeyIdentifier', 'keyid:always', false],
  ].freeze
  SERVER_EXTENSIONS = [
    ['keyUsage', 'digitalSignature,keyEncipherment', true],
    ['subjectKeyIdentifier', 'hash', false],
    ['extendedKeyUsage', SSL_SERVER_CERT_OID.to_s, true],
  ].freeze

  DEFAULT_SIGNING_DIGEST = OpenSSL::Digest::SHA256.new

  def create_private_key
    OpenSSL::PKey::RSA.new(PRIVATE_KEY_LENGTH)
  end

  def create_self_signed_ca(key, name)
    cert = OpenSSL::X509::Certificate.new

    cert.public_key = key.public_key
    cert.subject = OpenSSL::X509::Name.parse(name)
    cert.issuer = cert.subject
    cert.version = 2
    cert.serial = rand(2**128)

    not_before = just_now
    cert.not_before = not_before
    cert.not_after = not_before + FIFTEEN_YEARS_SECONDS

    ext_factory = extension_factory_for(cert, cert)
    CA_EXTENSIONS.each do |ext|
      extension = ext_factory.create_extension(*ext)
      cert.add_extension(extension)
    end

    cert.sign(key, DEFAULT_SIGNING_DIGEST)

    cert
  end

  def create_csr(key, name)
    csr = OpenSSL::X509::Request.new

    csr.public_key = key.public_key
    csr.subject = OpenSSL::X509::Name.parse(name)
    csr.version = 2
    csr.sign(key, DEFAULT_SIGNING_DIGEST)

    csr
  end

  def sign(hostname, ca_key, ca_cert, csr)
    cert = OpenSSL::X509::Certificate.new

    cert.public_key = csr.public_key
    cert.subject = csr.subject
    cert.issuer = ca_cert.subject
    cert.version = 2
    cert.serial = rand(2**128)

    not_before = just_now
    cert.not_before = not_before
    cert.not_after = not_before + FIFTEEN_YEARS_SECONDS

    ext_factory = extension_factory_for(ca_cert, cert)
    SERVER_EXTENSIONS.each do |ext|
      extension = ext_factory.create_extension(*ext)
      cert.add_extension(extension)
    end

    type_string = if (hostname =~ Resolv::IPv4::Regex) || (hostname =~ Resolv::IPv6::Regex)
                    'IP'
                  else
                    'DNS'
                  end
    alt_names_ext = ext_factory.create_extension('subjectAltName', "#{type_string}:#{hostname}", false)
    cert.add_extension(alt_names_ext)

    cert.sign(ca_key, DEFAULT_SIGNING_DIGEST)

    cert
  end

  # Returns a Time object for one minute ago,
  # to give some tolerance for clock skew
  def just_now
    Time.now - 60
  end

  def create_crl_for(cert, key)
    crl = OpenSSL::X509::CRL.new
    crl.version = 1
    crl.issuer = cert.subject

    ef = extension_factory_for(cert)
    crl.add_extension(ef.create_extension(['authorityKeyIdentifier', 'keyid:always', false]))
    crl.add_extension(OpenSSL::X509::Extension.new('crlNumber', OpenSSL::ASN1::Integer(0)))

    crl.last_update = just_now
    crl.next_update = just_now + FIFTEEN_YEARS_SECONDS
    crl.sign(key, DEFAULT_SIGNING_DIGEST)

    crl
  end

  def extension_factory_for(ca, cert = nil)
    ef = OpenSSL::X509::ExtensionFactory.new
    ef.issuer_certificate  = ca
    ef.subject_certificate = cert if cert

    ef
  end
end