Add a `pipeline` context option for SanitizationFilter

When this option is `:description`, we use a more restrictive whitelist.
This is used for Project and Group description fields.

2 files changed, 40 insertions, 21 deletions

diff --git a/lib/gitlab/markdown.rb b/lib/gitlab/markdown.rb
index 5db1566f55d..fa9c0975bb8 100644
--- a/lib/gitlab/markdown.rb
+++ b/lib/gitlab/markdown.rb
@@ -57,6 +57,9 @@ module Gitlab
       pipeline = HTML::Pipeline.new(filters)
 
       context = {
+        # SanitizationFilter
+        pipeline: options[:pipeline],
+
         # EmojiFilter
         asset_root: Gitlab.config.gitlab.url,
         asset_host: Gitlab::Application.config.asset_host,
diff --git a/lib/gitlab/markdown/sanitization_filter.rb b/lib/gitlab/markdown/sanitization_filter.rb
index 88781fea0c8..fc29d09081a 100644
--- a/lib/gitlab/markdown/sanitization_filter.rb
+++ b/lib/gitlab/markdown/sanitization_filter.rb
@@ -8,33 +8,53 @@ module Gitlab
     # Extends HTML::Pipeline::SanitizationFilter with a custom whitelist.
     class SanitizationFilter < HTML::Pipeline::SanitizationFilter
       def whitelist
-        whitelist = super
+        # Descriptions are more heavily sanitized, allowing only a few elements.
+        # See http://git.io/vkuAN
+        if pipeline == :description
+          whitelist = LIMITED
+        else
+          whitelist = super
+        end
+
+        customize_whitelist(whitelist)
+
+        whitelist
+      end
 
+      private
+
+      def pipeline
+        context[:pipeline] || :default
+      end
+
+      def customized?(transformers)
+        transformers.last.source_location[0] == __FILE__
+      end
+
+      def customize_whitelist(whitelist)
         # Only push these customizations once
-        unless customized?(whitelist[:transformers])
-          # Allow code highlighting
-          whitelist[:attributes]['pre'] = %w(class)
-          whitelist[:attributes]['span'] = %w(class)
+        return if customized?(whitelist[:transformers])
 
-          # Allow table alignment
-          whitelist[:attributes]['th'] = %w(style)
-          whitelist[:attributes]['td'] = %w(style)
+        # Allow code highlighting
+        whitelist[:attributes]['pre'] = %w(class)
+        whitelist[:attributes]['span'] = %w(class)
 
-          # Allow span elements
-          whitelist[:elements].push('span')
+        # Allow table alignment
+        whitelist[:attributes]['th'] = %w(style)
+        whitelist[:attributes]['td'] = %w(style)
 
-          # Remove `rel` attribute from `a` elements
-          whitelist[:transformers].push(remove_rel)
+        # Allow span elements
+        whitelist[:elements].push('span')
 
-          # Remove `class` attribute from non-highlight spans
-          whitelist[:transformers].push(clean_spans)
-        end
+        # Remove `rel` attribute from `a` elements
+        whitelist[:transformers].push(remove_rel)
+
+        # Remove `class` attribute from non-highlight spans
+        whitelist[:transformers].push(clean_spans)
 
         whitelist
       end
 
-      private
-
       def remove_rel
         lambda do |env|
           if env[:node_name] == 'a'
@@ -53,10 +73,6 @@ module Gitlab
           end
         end
       end
-
-      def customized?(transformers)
-        transformers.last.source_location[0] == __FILE__
-      end
     end
   end
 end