Fix for redirect_to to respect urls with a network path reference like "//asset.host.com/resources/1235" see issue #3856

2 files changed, 12 insertions, 2 deletions

diff --git a/actionpack/lib/action_controller/metal/redirecting.rb b/actionpack/lib/action_controller/metal/redirecting.rb
index 0355c9f458..7d14b175cc 100644
--- a/actionpack/lib/action_controller/metal/redirecting.rb
+++ b/actionpack/lib/action_controller/metal/redirecting.rb
@@ -18,7 +18,7 @@ module ActionController
     #
     # * <tt>Hash</tt> - The URL will be generated by calling url_for with the +options+.
     # * <tt>Record</tt> - The URL will be generated by calling url_for with the +options+, which will reference a named URL for that record.
-    # * <tt>String</tt> starting with <tt>protocol://</tt> (like <tt>http://</tt>) - Is passed straight through as the target for redirection.
+    # * <tt>String</tt> starting with <tt>protocol://</tt> (like <tt>http://</tt>) or a protocol relative reference (like <tt>//</tt>) - Is passed straight through as the target for redirection.
     # * <tt>String</tt> not containing a protocol - The current protocol and host is prepended to the string.
     # * <tt>Proc</tt> - A block that will be executed in the controller's context. Should return any option accepted by +redirect_to+.
     # * <tt>:back</tt> - Back to the page that issued the request. Useful for forms that are triggered from multiple places.
@@ -81,7 +81,7 @@ module ActionController
         # The scheme name consist of a letter followed by any combination of
         # letters, digits, and the plus ("+"), period ("."), or hyphen ("-")
         # characters; and is terminated by a colon (":").
-        when %r{^\w[\w+.-]*:.*}
+        when %r{^(\w[\w+.-]*:|\/\/).*}
           options
         when String
           request.protocol + request.host_with_port + options
diff --git a/actionpack/test/controller/redirect_test.rb b/actionpack/test/controller/redirect_test.rb
index 79041055bd..5b739e49ac 100644
--- a/actionpack/test/controller/redirect_test.rb
+++ b/actionpack/test/controller/redirect_test.rb
@@ -70,6 +70,10 @@ class RedirectController < ActionController::Base
     redirect_to "x-test+scheme.complex:redirect"
   end
 
+  def redirect_to_url_with_network_path_reference
+    redirect_to "//www.rubyonrails.org/"
+  end
+
   def redirect_to_back
     redirect_to :back
   end
@@ -216,6 +220,12 @@ class RedirectTest < ActionController::TestCase
     assert_equal "x-test+scheme.complex:redirect", redirect_to_url
   end
 
+  def test_redirect_to_url_with_network_path_reference
+    get :redirect_to_url_with_network_path_reference
+    assert_response :redirect
+    assert_equal "//www.rubyonrails.org/", redirect_to_url
+  end
+
   def test_redirect_to_back
     @request.env["HTTP_REFERER"] = "http://www.example.com/coming/from"
     get :redirect_to_back