Change the CSRF whitelisting to only apply to get requests

Unfortunately the previous method of browser detection and XHR whitelisting is unable to prevent requests issued from some Flash animations and Java applets.  To ease the work required to include the CSRF token in ajax requests rails now supports providing the token in a custom http header:

 X-CSRF-Token: ...

This fixes CVE-2011-0447

1 files changed, 9 insertions, 10 deletions

diff --git a/actionpack/lib/action_controller/metal/request_forgery_protection.rb b/actionpack/lib/action_controller/metal/request_forgery_protection.rb
index 148efbb081..b89e03bfb6 100644
--- a/actionpack/lib/action_controller/metal/request_forgery_protection.rb
+++ b/actionpack/lib/action_controller/metal/request_forgery_protection.rb
@@ -71,25 +71,24 @@ module ActionController #:nodoc:
     end
 
     protected
-
-      def protect_from_forgery(options = {})
-        self.request_forgery_protection_token ||= :authenticity_token
-        before_filter :verify_authenticity_token, options
-      end
-
       # The actual before_filter that is used.  Modify this to change how you handle unverified requests.
       def verify_authenticity_token
-        verified_request? || raise(ActionController::InvalidAuthenticityToken)
+        verified_request? || handle_unverified_request
+      end
+
+      def handle_unverified_request
+        reset_session
       end
 
       # Returns true or false if a request is verified.  Checks:
       #
-      # * is the format restricted?  By default, only HTML requests are checked.
       # * is it a GET request?  Gets should be safe and idempotent
       # * Does the form_authenticity_token match the given token value from the params?
+      # * Does the X-CSRF-Token header match the form_authenticity_token
       def verified_request?
-        !protect_against_forgery? || request.forgery_whitelisted? ||
-          form_authenticity_token == params[request_forgery_protection_token]
+        !protect_against_forgery? || request.get? ||
+          form_authenticity_token == params[request_forgery_protection_token] ||
+          form_authenticity_token == request.headers['X-CSRF-Token']
       end
 
       # Sets the token value for the current session.