Path parameters should default to UTF8

This commit changes the behavior such the path_params now default to
UTF8 just like regular parameters. This also changes the behavior such
that if a path parameter contains invalid UTF8 it returns a 400 bad
request. Previously the behavior was to encode the path params as binary
but that's not the same as query params.

So this commit makes path params behave the same as query params.

It's important to test with a path that's encoded as binary because
that's how paths are encoded from the socket. The test that was altered
was changed to make the behavior for bad encoding the same as query
params. We want to treat path params the same as query params. The params
in the test are invalid UTF8 so they should return a bad request.

Fixes #29669

*Eileen M. Uchitelle, Aaron Patterson, & Tsukuru Tanimichi*

3 files changed, 20 insertions, 10 deletions

diff --git a/actionpack/lib/action_dispatch/http/parameters.rb b/actionpack/lib/action_dispatch/http/parameters.rb
index d80d1d714c..ae875eb830 100644
--- a/actionpack/lib/action_dispatch/http/parameters.rb
+++ b/actionpack/lib/action_dispatch/http/parameters.rb
@@ -57,7 +57,7 @@ module ActionDispatch
                    query_parameters.dup
                  end
         params.merge!(path_parameters)
-        params = set_binary_encoding(params)
+        params = set_binary_encoding(params, params[:controller], params[:action])
         set_header("action_dispatch.request.parameters", params)
         params
       end
@@ -66,6 +66,7 @@ module ActionDispatch
       def path_parameters=(parameters) #:nodoc:
         delete_header("action_dispatch.request.parameters")
 
+        parameters = set_binary_encoding(parameters, parameters[:controller], parameters[:action])
         # If any of the path parameters has an invalid encoding then
         # raise since it's likely to trigger errors further on.
         Request::Utils.check_param_encoding(parameters)
@@ -85,9 +86,10 @@ module ActionDispatch
 
       private
 
-        def set_binary_encoding(params)
-          action = params[:action]
-          if binary_params_for?(action)
+        def set_binary_encoding(params, controller, action)
+          return params unless controller && controller.valid_encoding?
+
+          if binary_params_for?(controller, action)
             ActionDispatch::Request::Utils.each_param_value(params) do |param|
               param.force_encoding ::Encoding::ASCII_8BIT
             end
@@ -95,8 +97,8 @@ module ActionDispatch
           params
         end
 
-        def binary_params_for?(action)
-          controller_class.binary_params_for?(action)
+        def binary_params_for?(controller, action)
+          controller_class_for(controller).binary_params_for?(action)
         rescue NameError
           false
         end
diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
index 94b0d4880c..0b38ab7afb 100644
--- a/actionpack/lib/action_dispatch/http/request.rb
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -76,10 +76,13 @@ module ActionDispatch
 
     def controller_class
       params = path_parameters
+      params[:action] ||= "index"
+      controller_class_for(params[:controller])
+    end
 
-      if params.key?(:controller)
-        controller_param = params[:controller].underscore
-        params[:action] ||= "index"
+    def controller_class_for(name)
+      if name
+        controller_param = name.underscore
         const_name = "#{controller_param.camelize}Controller"
         ActiveSupport::Dependencies.constantize(const_name)
       else
diff --git a/actionpack/lib/action_dispatch/journey/router.rb b/actionpack/lib/action_dispatch/journey/router.rb
index 809bfcbe8a..9987a9bfa1 100644
--- a/actionpack/lib/action_dispatch/journey/router.rb
+++ b/actionpack/lib/action_dispatch/journey/router.rb
@@ -43,6 +43,10 @@ module ActionDispatch
             req.path_info = "/" + req.path_info unless req.path_info.start_with? "/"
           end
 
+          parameters = route.defaults.merge parameters.transform_values { |val|
+            val.dup.force_encoding(::Encoding::UTF_8)
+          }
+
           req.path_parameters = set_params.merge parameters
 
           status, headers, body = route.app.serve(req)
@@ -67,6 +71,7 @@ module ActionDispatch
             rails_req.path_info   = match.post_match.sub(/^([^\/])/, '/\1')
           end
 
+          parameters = route.defaults.merge parameters
           yield(route, parameters)
         end
       end
@@ -119,7 +124,7 @@ module ActionDispatch
 
           routes.map! { |r|
             match_data = r.path.match(req.path_info)
-            path_parameters = r.defaults.dup
+            path_parameters = {}
             match_data.names.zip(match_data.captures) { |name, val|
               path_parameters[name.to_sym] = Utils.unescape_uri(val) if val
             }