Merge branch 'rs-data-links' into 'master'

Sanitize `data` and `vbscript` links

Closes #13625 

Closes https://dev.gitlab.org/gitlab/gitlabhq/issues/2660

See merge request !2905

1 files changed, 6 insertions, 4 deletions

diff --git a/lib/banzai/filter/sanitization_filter.rb b/lib/banzai/filter/sanitization_filter.rb
index 04ddfe53ed6..abd79b329ae 100644
--- a/lib/banzai/filter/sanitization_filter.rb
+++ b/lib/banzai/filter/sanitization_filter.rb
@@ -7,6 +7,8 @@ module Banzai
     #
     # Extends HTML::Pipeline::SanitizationFilter with a custom whitelist.
     class SanitizationFilter < HTML::Pipeline::SanitizationFilter
+      UNSAFE_PROTOCOLS = %w(javascript :javascript data vbscript).freeze
+
       def whitelist
         whitelist = super
 
@@ -43,8 +45,8 @@ module Banzai
         # Allow any protocol in `a` elements...
         whitelist[:protocols].delete('a')
 
-        # ...but then remove links with the `javascript` protocol
-        whitelist[:transformers].push(remove_javascript_links)
+        # ...but then remove links with unsafe protocols
+        whitelist[:transformers].push(remove_unsafe_links)
 
         # Remove `rel` attribute from `a` elements
         whitelist[:transformers].push(remove_rel)
@@ -55,14 +57,14 @@ module Banzai
         whitelist
       end
 
-      def remove_javascript_links
+      def remove_unsafe_links
         lambda do |env|
           node = env[:node]
 
           return unless node.name == 'a'
           return unless node.has_attribute?('href')
 
-          if node['href'].start_with?('javascript', ':javascript')
+          if node['href'].start_with?(*UNSAFE_PROTOCOLS)
             node.remove_attribute('href')
           end
         end