From 50931f4a4309f34bc15daf4ff2f3d649e7972448 Mon Sep 17 00:00:00 2001
From: Christian Kissner <christian.kissner.-nd@disney.com>
Date: Tue, 25 Aug 2020 17:00:04 +0000
Subject: [PATCH] scrub_css should not drop `!important` from shorthand css
 props

part of #191
---
 lib/loofah/html5/scrub.rb                 | 2 ++
 test/assets/testdata_sanitizer_tests1.dat | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/lib/loofah/html5/scrub.rb b/lib/loofah/html5/scrub.rb
index 6375d15a..8a4c806d 100644
--- a/lib/loofah/html5/scrub.rb
+++ b/lib/loofah/html5/scrub.rb
@@ -8,6 +8,7 @@ module Scrub
       CONTROL_CHARACTERS = /[`\u0000-\u0020\u007f\u0080-\u0101]/
       CSS_KEYWORDISH = /\A(#[0-9a-fA-F]+|rgb\(\d+%?,\d*%?,?\d*%?\)?|-?\d{0,3}\.?\d{0,10}(ch|cm|r?em|ex|in|lh|mm|pc|pt|px|Q|vmax|vmin|vw|vh|%|,|\))?)\z/
       CRASS_SEMICOLON = { :node => :semicolon, :raw => ";" }
+      CSS_IMPORTANT = '!important'
 
       class << self
         def allowed_element?(element_name)
@@ -90,6 +91,7 @@ def scrub_css(style)
                 end
               end.compact
               unless value.empty?
+                value += [CSS_IMPORTANT] if node[:important]
                 propstring = sprintf "%s:%s", name, value.join(" ")
                 sanitized_node = Crass.parse_properties(propstring).first
                 sanitized_tree << sanitized_node << CRASS_SEMICOLON
diff --git a/test/assets/testdata_sanitizer_tests1.dat b/test/assets/testdata_sanitizer_tests1.dat
index c7a5f063..b5646464 100644
--- a/test/assets/testdata_sanitizer_tests1.dat
+++ b/test/assets/testdata_sanitizer_tests1.dat
@@ -486,6 +486,14 @@
     "rexml": "<div style='color: blue;'></div>"
   },
 
+ {
+    "name": "style_attr_shorhand_important",
+    "input": "<div style=\"border: 2px dashed gray !important;\" />",
+    "output": "<div style='border:2px dashed gray !important;/>",
+    "xhtml": "<div style='border:2px dashed gray !important;'></div>",
+    "rexml": "<div style='border:2px dashed gray !important;'></div>"
+  },
+
   {
    "name": "attributes_with_embedded_quotes",
    "input": "<img src=doesntexist.jpg\"'onerror=\"alert(1) />",