From 2c510ee00a9fb4141a428d9a21dbd561171b3409 Mon Sep 17 00:00:00 2001
From: Thibaut Girka <thib@sitedethib.com>
Date: Sun, 22 Mar 2020 16:59:29 +0100
Subject: [PATCH] Fix glitch-soc marking every link in toots as a tag

Fixes #1281
---
 app/lib/formatter.rb             |  2 +-
 app/lib/sanitize_config.rb       | 11 ++++++++++-
 spec/lib/sanitize_config_spec.rb |  6 +++++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/app/lib/formatter.rb b/app/lib/formatter.rb
index fcc99d0095b..b7a0286d2d6 100644
--- a/app/lib/formatter.rb
+++ b/app/lib/formatter.rb
@@ -131,7 +131,7 @@ class Formatter
   end
 
   def link_url(url)
-    "<a href=\"#{encode(url)}\" target=\"blank\" rel=\"nofollow noopener\">#{link_html(url)}</a>"
+    "<a href=\"#{encode(url)}\" target=\"blank\" rel=\"nofollow noopener noreferrer\">#{link_html(url)}</a>"
   end
 
   private
diff --git a/app/lib/sanitize_config.rb b/app/lib/sanitize_config.rb
index e3fc94ba637..8bbcca4ce5c 100644
--- a/app/lib/sanitize_config.rb
+++ b/app/lib/sanitize_config.rb
@@ -54,6 +54,15 @@ class Sanitize
       end
     end
 
+    LINK_REL_TRANSFORMER = lambda do |env|
+      return unless env[:node_name] == 'a'
+
+      node = env[:node]
+
+      rel = (node['rel'] || '').split(' ') & ['tag']
+      node['rel'] = (['nofollow', 'noopener', 'noreferrer'] + rel).join(' ')
+    end
+
     UNSUPPORTED_HREF_TRANSFORMER = lambda do |env|
       return unless env[:node_name] == 'a'
 
@@ -82,7 +91,6 @@ class Sanitize
 
       add_attributes: {
         'a' => {
-          'rel' => 'nofollow noopener tag noreferrer',
           'target' => '_blank',
         },
       },
@@ -95,6 +103,7 @@ class Sanitize
       transformers: [
         CLASS_WHITELIST_TRANSFORMER,
         IMG_TAG_TRANSFORMER,
+        LINK_REL_TRANSFORMER,
         UNSUPPORTED_HREF_TRANSFORMER,
       ]
     )
diff --git a/spec/lib/sanitize_config_spec.rb b/spec/lib/sanitize_config_spec.rb
index 50558a0d816..2d82c00eaf2 100644
--- a/spec/lib/sanitize_config_spec.rb
+++ b/spec/lib/sanitize_config_spec.rb
@@ -28,7 +28,11 @@ describe Sanitize::Config do
     end
 
     it 'keeps a with href' do
-      expect(Sanitize.fragment('<a href="http://example.com">Test</a>', subject)).to eq '<a href="http://example.com" rel="nofollow noopener tag noreferrer" target="_blank">Test</a>'
+      expect(Sanitize.fragment('<a href="http://example.com">Test</a>', subject)).to eq '<a href="http://example.com" rel="nofollow noopener noreferrer" target="_blank">Test</a>'
+    end
+
+    it 'keeps a with href and rel tag' do
+      expect(Sanitize.fragment('<a href="http://example.com" rel="tag">Test</a>', subject)).to eq '<a href="http://example.com" rel="nofollow noopener noreferrer tag" target="_blank">Test</a>'
     end
   end
 end