1 files changed, 37 insertions, 0 deletions
diff --git a/lib/gitlab/sanitizers/svg.rb b/lib/gitlab/sanitizers/svg.rb
new file mode 100644
index 00000000000..b98589dff89
--- /dev/null
+++ b/lib/gitlab/sanitizers/svg.rb
@@ -0,0 +1,37 @@
+require_relative "svg/whitelist"
+
+module Gitlab
+  module Sanitizers
+    module SVG
+      def self.clean(data)
+        Loofah.xml_document(data).scrub!(Scrubber.new).to_s
+      end
+
+      class Scrubber < Loofah::Scrubber
+        # http://www.whatwg.org/specs/web-apps/current-work/multipage/elements.html#embedding-custom-non-visible-data-with-the-data-*-attributes
+        DATA_ATTR_PATTERN = /\Adata-(?!xml)[a-z_][\w.\u00E0-\u00F6\u00F8-\u017F\u01DD-\u02AF-]*\z/u
+
+        def scrub(node)
+          unless ALLOWED_ELEMENTS.include?(node.name)
+            node.unlink
+          else
+            node.attributes.each do |attr_name, attr|
+              valid_attributes = ALLOWED_ATTRIBUTES[node.name]
+
+              unless valid_attributes && valid_attributes.include?(attr_name)
+                if ALLOWED_DATA_ATTRIBUTES_IN_ELEMENTS.include?(node.name) &&
+                    attr_name.start_with?('data-')
+                  # Arbitrary data attributes are allowed. Verify that the attribute
+                  # is a valid data attribute.
+                  attr.unlink unless attr_name =~ DATA_ATTR_PATTERN
+                else
+                  attr.unlink
+                end
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end