Action Dispatch HostAuthorization

This middleware guards from DNS rebinding attacks by explicitly permitting the hosts a request can be sent to, and is passed the options set in config.host_authorization.

Requests can opt-out of Host Authorization with exclude:

config.host_authorization = { exclude: ->(request) { request.path =~ /healthcheck/ } }

When a request comes to an unauthorized host, the response_app application will be executed and rendered. If no response_app is given, a default one will run. The default response app logs blocked host info with level ‘error’ and responds with 403 Forbidden. The body of the response contains debug info if config.consider_all_requests_local is set to true, otherwise the body is empty.

Methods

Constants

ALLOWED_HOSTS_IN_DEVELOPMENT = [".localhost", IPAddr.new("0.0.0.0/0"), IPAddr.new("::/0")]

Class Public methods

new(app, hosts, exclude: nil, response_app: nil)

📝 Source code
# File actionpack/lib/action_dispatch/middleware/host_authorization.rb, line 125
    def initialize(app, hosts, exclude: nil, response_app: nil)
      @app = app
      @permissions = Permissions.new(hosts)
      @exclude = exclude

      @response_app = response_app || DefaultResponseApp.new
    end
🔎 See on GitHub

Instance Public methods

call(env)

📝 Source code
# File actionpack/lib/action_dispatch/middleware/host_authorization.rb, line 133
    def call(env)
      return @app.call(env) if @permissions.empty?

      request = Request.new(env)
      hosts = blocked_hosts(request)

      if hosts.empty? || excluded?(request)
        mark_as_authorized(request)
        @app.call(env)
      else
        env["action_dispatch.blocked_hosts"] = hosts
        @response_app.call(env)
      end
    end
🔎 See on GitHub