gitlabhq/gitlab-ci

module UserSessionsHelper
  def generate_oauth_salt
    SecureRandom.hex(16)
  end

  def generate_oauth_hmac(salt, return_to)
    return unless return_to
    digest = OpenSSL::Digest.new('sha256')
    key = GitlabCi::Application.secrets.secret_key_base + salt
    OpenSSL::HMAC.hexdigest(digest, key, return_to)
  end

  def generate_oauth_state(return_to)
    return unless return_to
    salt = generate_oauth_salt
    hmac = generate_oauth_hmac(salt, return_to)
    "#{salt}:#{hmac}:#{return_to}"
  end

  def get_ouath_state_return_to(state)
    state.split(':', 3)[2] if state
  end

  def is_oauth_state_valid?(state)
    return true unless state
    salt, hmac, return_to = state.split(':', 3)
    return false unless return_to
    hmac == generate_oauth_hmac(salt, return_to)
  end
end