cert_command.rb

# frozen_string_literal: true

require_relative "../command"
require_relative "../security"

class Gem::Commands::CertCommand < Gem::Command
  def initialize
    super "cert", "Manage RubyGems certificates and signing settings",
          add: [], remove: [], list: [], build: [], sign: []

    add_option("-a", "--add CERT",
               "Add a trusted certificate.") do |cert_file, options|
      options[:add] << open_cert(cert_file)
    end

    add_option("-l", "--list [FILTER]",
               "List trusted certificates where the",
               "subject contains FILTER") do |filter, options|
      filter ||= ""

      options[:list] << filter
    end

    add_option("-r", "--remove FILTER",
               "Remove trusted certificates where the",
               "subject contains FILTER") do |filter, options|
      options[:remove] << filter
    end

    add_option("-b", "--build EMAIL_ADDR",
               "Build private key and self-signed",
               "certificate for EMAIL_ADDR") do |email_address, options|
      options[:build] << email_address
    end

    add_option("-C", "--certificate CERT",
               "Signing certificate for --sign") do |cert_file, options|
      options[:issuer_cert] = open_cert(cert_file)
      options[:issuer_cert_file] = cert_file
    end

    add_option("-K", "--private-key KEY",
               "Key for --sign or --build") do |key_file, options|
      options[:key] = open_private_key(key_file)
    end

    add_option("-A", "--key-algorithm ALGORITHM",
               "Select which key algorithm to use for --build") do |algorithm, options|
      options[:key_algorithm] = algorithm
    end

    add_option("-s", "--sign CERT",
               "Signs CERT with the key from -K",
               "and the certificate from -C") do |cert_file, options|
      raise Gem::OptionParser::InvalidArgument, "#{cert_file}: does not exist" unless
        File.file? cert_file

      options[:sign] << cert_file
    end

    add_option("-d", "--days NUMBER_OF_DAYS",
               "Days before the certificate expires") do |days, options|
      options[:expiration_length_days] = days.to_i
    end

    add_option("-R", "--re-sign",
               "Re-signs the certificate from -C with the key from -K") do |resign, options|
      options[:resign] = resign
    end
  end

  def add_certificate(certificate) # :nodoc:
    Gem::Security.trust_dir.trust_cert certificate

    say "Added '#{certificate.subject}'"
  end

  def check_openssl
    return if Gem::HAVE_OPENSSL

    alert_error "OpenSSL library is required for the cert command"
    terminate_interaction 1
  end

  def open_cert(certificate_file)
    check_openssl
    OpenSSL::X509::Certificate.new File.read certificate_file
  rescue Errno::ENOENT
    raise Gem::OptionParser::InvalidArgument, "#{certificate_file}: does not exist"
  rescue OpenSSL::X509::CertificateError
    raise Gem::OptionParser::InvalidArgument,
      "#{certificate_file}: invalid X509 certificate"
  end

  def open_private_key(key_file)
    check_openssl
    passphrase = ENV["GEM_PRIVATE_KEY_PASSPHRASE"]
    key = OpenSSL::PKey.read File.read(key_file), passphrase
    raise Gem::OptionParser::InvalidArgument,
      "#{key_file}: private key not found" unless key.private?
    key
  rescue Errno::ENOENT
    raise Gem::OptionParser::InvalidArgument, "#{key_file}: does not exist"
  rescue OpenSSL::PKey::PKeyError, ArgumentError
    raise Gem::OptionParser::InvalidArgument, "#{key_file}: invalid RSA, DSA, or EC key"
  end

  def execute
    check_openssl

    options[:add].each do |certificate|
      add_certificate certificate
    end

    options[:remove].each do |filter|
      remove_certificates_matching filter
    end

    options[:list].each do |filter|
      list_certificates_matching filter
    end

    options[:build].each do |email|
      build email
    end

    if options[:resign]
      re_sign_cert(
        options[:issuer_cert],
        options[:issuer_cert_file],
        options[:key]
      )
    end

    sign_certificates unless options[:sign].empty?
  end

  def build(email)
    unless valid_email?(email)
      raise Gem::CommandLineError, "Invalid email address #{email}"
    end

    key, key_path = build_key
    cert_path = build_cert email, key

    say "Certificate: #{cert_path}"

    if key_path
      say "Private Key: #{key_path}"
      say "Don't forget to move the key file to somewhere private!"
    end
  end

  def build_cert(email, key) # :nodoc:
    expiration_length_days = options[:expiration_length_days] ||
                             Gem.configuration.cert_expiration_length_days

    cert = Gem::Security.create_cert_email(
      email,
      key,
      (Gem::Security::ONE_DAY * expiration_length_days)
    )

    Gem::Security.write cert, "gem-public_cert.pem"
  end

  def build_key # :nodoc:
    return options[:key] if options[:key]

    passphrase = ask_for_password "Passphrase for your Private Key:"
    say "\n"

    passphrase_confirmation = ask_for_password "Please repeat the passphrase for your Private Key:"
    say "\n"

    raise Gem::CommandLineError,
          "Passphrase and passphrase confirmation don't match" unless passphrase == passphrase_confirmation

    algorithm = options[:key_algorithm] || Gem::Security::DEFAULT_KEY_ALGORITHM
    key = Gem::Security.create_key(algorithm)
    key_path = Gem::Security.write key, "gem-private_key.pem", 0o600, passphrase

    [key, key_path]
  end

  def certificates_matching(filter)
    return enum_for __method__, filter unless block_given?

    Gem::Security.trusted_certificates.select do |certificate, _|
      subject = certificate.subject.to_s
      subject.downcase.index filter
    end.sort_by do |certificate, _|
      certificate.subject.to_a.map {|name, data,| [name, data] }
    end.each do |certificate, path|
      yield certificate, path
    end
  end

  def description # :nodoc:
    <<-EOF
The cert command manages signing keys and certificates for creating signed
gems.  Your signing certificate and private key are typically stored in
~/.gem/gem-public_cert.pem and ~/.gem/gem-private_key.pem respectively.

To build a certificate for signing gems:

  gem cert --build you@example

If you already have an RSA key, or are creating a new certificate for an
existing key:

  gem cert --build you@example --private-key /path/to/key.pem

If you wish to trust a certificate you can add it to the trust list with:

  gem cert --add /path/to/cert.pem

You can list trusted certificates with:

  gem cert --list

or:

  gem cert --list cert_subject_substring

If you wish to remove a previously trusted certificate:

  gem cert --remove cert_subject_substring

To sign another gem author's certificate:

  gem cert --sign /path/to/other_cert.pem

For further reading on signing gems see `ri Gem::Security`.
    EOF
  end

  def list_certificates_matching(filter) # :nodoc:
    certificates_matching filter do |certificate, _|
      # this could probably be formatted more gracefully
      say certificate.subject.to_s
    end
  end

  def load_default_cert
    cert_file = File.join Gem.default_cert_path
    cert = File.read cert_file
    options[:issuer_cert] = OpenSSL::X509::Certificate.new cert
  rescue Errno::ENOENT
    alert_error \
      "--certificate not specified and ~/.gem/gem-public_cert.pem does not exist"

    terminate_interaction 1
  rescue OpenSSL::X509::CertificateError
    alert_error \
      "--certificate not specified and ~/.gem/gem-public_cert.pem is not valid"

    terminate_interaction 1
  end

  def load_default_key
    key_file = File.join Gem.default_key_path
    key = File.read key_file
    passphrase = ENV["GEM_PRIVATE_KEY_PASSPHRASE"]
    options[:key] = OpenSSL::PKey.read key, passphrase
  rescue Errno::ENOENT
    alert_error \
      "--private-key not specified and ~/.gem/gem-private_key.pem does not exist"

    terminate_interaction 1
  rescue OpenSSL::PKey::PKeyError
    alert_error \
      "--private-key not specified and ~/.gem/gem-private_key.pem is not valid"

    terminate_interaction 1
  end

  def load_defaults # :nodoc:
    load_default_cert unless options[:issuer_cert]
    load_default_key  unless options[:key]
  end

  def remove_certificates_matching(filter) # :nodoc:
    certificates_matching filter do |certificate, path|
      FileUtils.rm path
      say "Removed '#{certificate.subject}'"
    end
  end

  def sign(cert_file)
    cert = File.read cert_file
    cert = OpenSSL::X509::Certificate.new cert

    permissions = File.stat(cert_file).mode & 0o777

    issuer_cert = options[:issuer_cert]
    issuer_key = options[:key]

    cert = Gem::Security.sign cert, issuer_key, issuer_cert

    Gem::Security.write cert, cert_file, permissions
  end

  def sign_certificates # :nodoc:
    load_defaults unless options[:sign].empty?

    options[:sign].each do |cert_file|
      sign cert_file
    end
  end

  def re_sign_cert(cert, cert_path, private_key)
    Gem::Security::Signer.re_sign_cert(cert, cert_path, private_key) do |expired_cert_path, new_expired_cert_path|
      alert("Your certificate #{expired_cert_path} has been re-signed")
      alert("Your expired certificate will be located at: #{new_expired_cert_path}")
    end
  end

  private

  def valid_email?(email)
    # It's simple, but is all we need
    email =~ /\A.+@.+\z/
  end
end