From be3e36601941ed69c911bf327333f2f5bed4c3ec Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Sat, 17 Feb 2024 19:57:44 -0500
Subject: [PATCH] Escape special whitespace characters in attribute values

Related issue:
https://github.com/uBlockOrigin/uBlock-issues/issues/3127

Reference:
https://mathiasbynens.be/notes/css-escapes
---
 src/js/static-filtering-parser.js | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/js/static-filtering-parser.js b/src/js/static-filtering-parser.js
index cc955c5f604d5..aa118c9dec198 100644
--- a/src/js/static-filtering-parser.js
+++ b/src/js/static-filtering-parser.js
@@ -3458,6 +3458,8 @@ class ExtSelectorCompiler {
 
     // https://github.com/uBlockOrigin/uBlock-issues/issues/2300
     //   Unquoted attribute values are parsed as Identifier instead of String.
+    // https://github.com/uBlockOrigin/uBlock-issues/issues/3127
+    //   Escape [\t\n\v\f\r]
     astSerializePart(part) {
         const out = [];
         const { data } = part;
@@ -3473,7 +3475,14 @@ class ExtSelectorCompiler {
             if ( typeof value !== 'string' ) {
                 value = data.value.name;
             }
-            value = value.replace(/["\\]/g, '\\$&');
+            if ( /["\\]/.test(value) ) {
+                value = value.replace(/["\\]/g, '\\$&');
+            }
+            if ( /[\x09-\x0D]/.test(value) ) {
+                value = value.replace(/[\x09-\x0D]/g, s =>
+                    `\\${s.charCodeAt(0).toString(16).toUpperCase()} `
+                );
+            }
             let flags = '';
             if ( typeof data.flags === 'string' ) {
                 if ( /^(is?|si?)$/.test(data.flags) === false ) { return; }