fix XSS vulnerability when using translation

[CVE-2024-26143]

Author: ooooooo-q

actionpack/lib/abstract_controller/translation.rb

@@ -23,7 +23,25 @@ def translate(key, **options)
         key = "#{path}.#{action_name}#{key}"
       end
 
-      ActiveSupport::HtmlSafeTranslation.translate(key, **options)
+      if options[:default]
+        options[:default] = [options[:default]] unless options[:default].is_a?(Array)
+        options[:default] = options[:default].map do |value|
+          value.is_a?(String) ? ERB::Util.html_escape(value) : value
+        end
+      end
+
+      if options[:raise].nil?
+        options[:default] = [] unless options[:default]
+        options[:default] << MISSING_TRANSLATION
+      end
+
+      result = ActiveSupport::HtmlSafeTranslation.translate(key, **options)
+
+      if result == MISSING_TRANSLATION
+        +"translation missing: #{key}"
+      else
+        result
+      end
     end
     alias :t :translate
 
@@ -32,5 +50,9 @@ def localize(object, **options)
       I18n.localize(object, **options)
     end
     alias :l :localize
+
+    private
+      MISSING_TRANSLATION = -(2**60)
+      private_constant :MISSING_TRANSLATION
   end
 end

actionpack/test/abstract/translation_test.rb

@@ -83,6 +83,22 @@ def test_default_translation
         end
       end
 
+      def test_default_translation_as_safe_html
+        @controller.stub :action_name, :index do
+          translation = @controller.t(".twoz", default: ["<tag>"])
+          assert_equal "&lt;tag&gt;", translation
+          assert_equal true, translation.html_safe?
+        end
+      end
+
+      def test_default_translation_with_raise_as_safe_html
+        @controller.stub :action_name, :index do
+          translation = @controller.t(".twoz", raise: true, default: ["<tag>"])
+          assert_equal "&lt;tag&gt;", translation
+          assert_equal true, translation.html_safe?
+        end
+      end
+
       def test_localize
         time, expected = Time.gm(2000), "Sat, 01 Jan 2000 00:00:00 +0000"
         I18n.stub :localize, expected do
@@ -126,6 +142,21 @@ def test_translate_escapes_interpolations_in_translations_with_a_html_suffix
           assert_equal true, translation.html_safe?
         end
       end
+
+      def test_translate_marks_translation_with_missing_html_key_as_safe_html
+        @controller.stub :action_name, :index do
+          translation = @controller.t("<tag>.html")
+          assert_equal "translation missing: <tag>.html", translation
+          assert_equal false, translation.html_safe?
+        end
+      end
+      def test_translate_marks_translation_with_missing_nested_html_key_as_safe_html
+        @controller.stub :action_name, :index do
+          translation = @controller.t(".<tag>.html")
+          assert_equal "translation missing: abstract_controller.testing.translation.index.<tag>.html", translation
+          assert_equal false, translation.html_safe?
+        end
+      end
     end
   end
 end