Module: LittleGhost::Network::CertificateAuthority

Defined in:
lib/little_ghost/network/certificate_authority.rb

Overview

Creates run-scoped trust material for opt-in HTTP inspection.

Class Method Summary collapse

Class Method Details

.certificate(subject:, key:, issuer:, issuer_key:, serial:, extensions:) ⇒ Object 



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# File 'lib/little_ghost/network/certificate_authority.rb', line 63

def certificate(subject:, key:, issuer:, issuer_key:, serial:, extensions:)
  certificate = OpenSSL::X509::Certificate.new
  certificate.version = 2
  certificate.serial = serial
  certificate.subject = OpenSSL::X509::Name.parse(subject)
  certificate.issuer = issuer ? issuer.subject : certificate.subject
  certificate.public_key = key.public_key
  certificate.not_before = Time.now - 60
  certificate.not_after = Time.now + (2 * 24 * 60 * 60)
  factory = OpenSSL::X509::ExtensionFactory.new
  factory.subject_certificate = certificate
  factory.issuer_certificate = issuer || certificate
  extensions.each { |name, value| certificate.add_extension(factory.create_extension(name, value)) }
  certificate.sign(issuer_key, OpenSSL::Digest.new("SHA256"))
  certificate
end

.create(root:, hosts:, trust_root: File.join(root, "trust")) ⇒ Object 



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# File 'lib/little_ghost/network/certificate_authority.rb', line 12

def create(root:, hosts:, trust_root: File.join(root, "trust"))
  LittleGhost.offload_blocking do
    create_material(root:, hosts:, trust_root:)
  end
end

.create_material(root:, hosts:, trust_root:) ⇒ Object 



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# File 'lib/little_ghost/network/certificate_authority.rb', line 18

def create_material(root:, hosts:, trust_root:)
  Dir.mkdir(trust_root, 0o700) unless Dir.exist?(trust_root)
  ca_key = OpenSSL::PKey::RSA.new(3072)
  ca_certificate = certificate(
    subject: "/CN=LittleGhost Ephemeral Egress CA",
    key: ca_key,
    issuer: nil,
    issuer_key: ca_key,
    serial: random_serial,
    extensions: [["basicConstraints", "critical,CA:TRUE"], ["keyUsage", "critical,keyCertSign,cRLSign"]]
  )
  leaf_key = OpenSSL::PKey::RSA.new(2048)
  leaf_certificate = certificate(
    subject: "/CN=LittleGhost Egress",
    key: leaf_key,
    issuer: ca_certificate,
    issuer_key: ca_key,
    serial: random_serial,
    extensions: [
      ["basicConstraints", "critical,CA:FALSE"],
      ["keyUsage", "critical,digitalSignature,keyEncipherment"],
      ["extendedKeyUsage", "serverAuth"],
      ["subjectAltName", hosts.map { |host| "DNS:#{host}" }.join(",")]
    ]
  )

  paths = {
    ca_key: File.join(root, "ca.key"),
    ca_certificate: File.join(trust_root, "ca.crt"),
    certificate_chain: File.join(root, "leaf.crt"),
    private_key: File.join(root, "leaf.key"),
    trust_bundle: File.join(trust_root, "ca-bundle.pem"),
    trust_store: File.join(trust_root, "ca.p12"),
    trust_root:
  }
  write(paths.fetch(:ca_key), ca_key.to_pem, 0o600)
  write(paths.fetch(:ca_certificate), ca_certificate.to_pem, 0o644)
  write(paths.fetch(:certificate_chain), leaf_certificate.to_pem, 0o644)
  write(paths.fetch(:private_key), leaf_key.to_pem, 0o600)
  system_bundle = File.file?(OpenSSL::X509::DEFAULT_CERT_FILE) ? File.binread(OpenSSL::X509::DEFAULT_CERT_FILE) : ""
  write(paths.fetch(:trust_bundle), "#{system_bundle}\n#{ca_certificate.to_pem}", 0o644)
  create_trust_store(paths.fetch(:ca_certificate), paths.fetch(:trust_store))
  paths.freeze
end

.create_trust_store(certificate, destination) ⇒ Object 



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# File 'lib/little_ghost/network/certificate_authority.rb', line 88

def create_trust_store(certificate, destination)
  _stdout, stderr, status = Open3.capture3(
    {}, "openssl", "pkcs12", "-export", "-nokeys", "-in", certificate,
    "-out", destination, "-passout", "pass:changeit", unsetenv_others: true
  )
  unless status.success?
    detail = stderr.lines.first.to_s.strip
    detail = "openssl pkcs12 failed" if detail.empty?
    raise DependencyError, "HTTP inspection could not create its Java trust store: #{detail}"
  end
  File.chmod(0o644, destination)
rescue Errno::ENOENT
  raise DependencyError, "HTTP inspection requires the openssl executable"
end

.random_serial ⇒ Object 



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# File 'lib/little_ghost/network/certificate_authority.rb', line 80

def random_serial
  OpenSSL::BN.rand(128).to_i
end

.write(path, content, mode) ⇒ Object 



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# File 'lib/little_ghost/network/certificate_authority.rb', line 84

def write(path, content, mode)
  File.open(path, File::WRONLY | File::CREAT | File::EXCL, mode) { |file| file.write(content) }
end