Prevent xss by not allowing return_to to point to javascript resources

3 files changed, 18 insertions, 4 deletions

diff --git a/app/controllers/events_controller.rb b/app/controllers/events_controller.rb
index 7695e9b..f50da3e 100644
--- a/app/controllers/events_controller.rb
+++ b/app/controllers/events_controller.rb
@@ -42,6 +42,7 @@ class EventsController < ApplicationController
   # GET /events/1/edit
   def edit
     @event = Event.find(params[:id])
+    @return_to = params[:return_to] || events_path
   end
 
   # POST /events
@@ -52,7 +53,7 @@ class EventsController < ApplicationController
     respond_to do |format|
       if @event.save
         flash[:notice] = 'Event was successfully created.'
-        format.html { redirect_to(edit_node_path(@event.node)) }
+        format.html { redirect_to(@event.node ? edit_node_path(@event.node) : edit_event_path(@event)) }
         format.xml  { render :xml => @event, :status => :created, :location => @event }
       else
         format.html { render :action => "new" }
@@ -69,7 +70,7 @@ class EventsController < ApplicationController
     respond_to do |format|
       if @event.update(event_params)
         flash[:notice] = 'Event was successfully updated.'
-        format.html { redirect_to(edit_node_path(@event.node)) }
+        format.html { redirect_to(safe_return_to(params[:return_to] || events_path)) }
         format.xml  { head :ok }
       else
         format.html { render :action => "edit" }
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 0be66e9..72b76b8 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -11,4 +11,14 @@ module ApplicationHelper
       end
     end
   end
+
+  def safe_return_to(url)
+    return events_path if url.blank?
+    uri = URI.parse(url)
+    return events_path if uri.host.present?
+    return events_path unless url.start_with?('/')
+    url
+  rescue URI::InvalidURIError
+    events_path
+  end
 end
diff --git a/app/views/events/edit.html.erb b/app/views/events/edit.html.erb
index 824cd66..17457df 100644
--- a/app/views/events/edit.html.erb
+++ b/app/views/events/edit.html.erb
@@ -1,12 +1,15 @@
 <% content_for :subnavigation do %>
-  <%= link_to 'back', edit_node_path(@event.node) %>
+  <%= link_to 'back', safe_return_to(params[:return_to] || events_path) %>
+  <% if @event.node %>
+    <%= link_to 'node', edit_node_path(@event.node) %>
+  <% end %>
   <%= link_to 'show', @event %>
 <% end %>
 
-
 <h1>Editing event</h1>
 
 <%= form_for(@event) do |f| %>
+  <%= hidden_field_tag :return_to, @return_to %>
   <%= form_error_messages(f) %>
 
   <p>