SafeCookies

This gem has a middleware that will make all cookies secure. In detail, it will to two separate things:

1) set all new application cookies 'HttpOnly', unless specified otherwise;
set all new application cookies 'secure', if the request came via HTTPS and not specified otherwise

2) rewrite request cookies, setting both flags as above

Installation

Step 1

Add gem 'safe_cookies' to your application's Gemfile, then run bundle install.

Step 2

Rails 3 and 4: add the following lines to the application block in config/application.rb:

require 'safe_cookies'
config.middleware.insert_before ActionDispatch::Cookies, SafeCookies::Middleware

Rails 2: add the following lines to the initializer block in config/environment.rb:

require 'safe_cookies'
config.middleware.insert_before ActionController::Session::CookieStore, SafeCookies::Middleware

Now all your cookies will be made secure and HttpOnly. But what if you need a cookie to be accessible via HTTP or Javascript?

Tell the middleware which cookies not to make secure or HttpOnly by registering them. Do it either just after the lines you added above or in an initializer (e.g. in config/initializers/safe_cookies.rb). The :expire_after option is required.

SafeCookies.configure do |config|
  config.register_cookie :default_language, :expire_after => 10.years, :secure => false
  config.register_cookie :javascript_data, :expire_after => 1.day, :http_only => false
end

Employing SafeCookies in apps that are already running in production

Unfortunately, the client won't ever tell us if it stores the cookie with flags such as secure or which expiry date it currently has. Therefore, in order to make the middleware retroactively secure cookies owned by the client, you need to register each of those cookies with the middleware, specifying their properties.

Carefully scan your app for cookies you are using. There's no easy way to find out if you missed one (but see below for some help the gem provides).

SafeCookies.configure do |config|
  config.register_cookie :remember_token, :expire_after => 1.year
  config.register_cookie :last_action, :expire_after => 30.days, :path => '/commerce'
end

Available options are: :expire_after (required), :path, :secure, :http_only.

Dealing with unknown cookies

There are lots of cookies your application receives that you never did set. However, if you want to know about any unknown cookies touching your application, SafeCookies offers two ways to achieve this.

1) If you set config.log_unknown_cookies = true in the configuration, all unknown cookies will be written to the Rails log. When you start implementing the middleware, closely watch it to find cookies you forgot to register.

2) You may overwrite SafeCookies::Middleware#handle_unknown_cookies(cookies) in the config initializer for customized behaviour (like, notifying you per email).

Ignoring cookies

The middleware won't see request cookies that are configured to be ignored. Use this to keep your logs lean, if you are using the log_unknown_cookies option.

You can tell the middleware to ignore cookies with the config.ignore_cookie directive, which takes either a String or a Regex parameter. Be careful when using regular expressions!

In August 2013 we noticed a bug in SafeCookies < 0.1.4, by which secured cookies would be set for the current "directory" (see comments in cookie_path_fix.rb) instead of root (which usually is what you want). Users would get multiple cookies for that domain, leading to issues like being unable to sign in.

The configuration option config.fix_paths turns on fixing this error. It requires an option :for_cookies_secured_before => Time.parse('some minutes after you will have deployed') which reflects the point of time from which cookies will be secured with the correct path. The middleware will fix the cookie paths by rewriting all cookies that it has already secured, but only if they were secured before the time you specified.

Development

  • Tests live in spec.
  • You can run specs from the project root by saying bundle exec rake.

If you would like to contribute:

  • Fork the repository.
  • Push your changes with passing specs.
  • Send us a pull request.