From 7aab9ae4266d70344f7d1b2f185c760b19cb6908 Mon Sep 17 00:00:00 2001
From: hackademix
Date: Wed, 24 Jul 2019 22:48:02 +0200
Subject: Fix paste sanitization bugs and make it work on drag and drop too.

---
 src/content/sanitizePaste.js | 71 ++++++++++++++++++++++++--------------------
 1 file changed, 38 insertions(+), 33 deletions(-)

diff --git a/src/content/sanitizePaste.js b/src/content/sanitizePaste.js
index 703f5b3..a1bcf53 100644
--- a/src/content/sanitizePaste.js
+++ b/src/content/sanitizePaste.js
@@ -1,58 +1,63 @@
 'use strict';
-
-window.addEventListener("paste", e => {
-  let data = e.clipboardData;
-  let html =  data.getData("text/html");
-  let t = e.target;
-  if (t.nodeType !== 1) t = t.parentElement;
-
-  try {
-    let node = t.cloneNode();
-
-    node.innerHTML = html;
-
-    if (sanitizeExtras(node)) {
-      let sanitized = node.innerHTML;
-      setTimeout(function() { try {
-        if (sanitizeExtras(t)) {
-          console.log(`[NoScript] Sanitized\n<PASTE>\n${html}\n</PASTE>to\n<PASTE>\n${t.innerHTML}\n</PASTE>`, t);
+{
+  let urlAttributes = ['href', 'to', 'from', 'by', 'values'];
+  let selector = urlAttributes.map(a => `[${a}]`).join(',');
+
+  for (let evType of ["drop", "paste"]) window.addEventListener(evType, e => {
+    let container = e.target;
+    let editing = false;
+    for (let el = container; el; el = el.parentElement) {
+      if (el.setRangeText || el.contentEditable) {
+        editing = true;
+        break;
+      }
+    }
+    if (!editing) return;
+
+    let html = container.innerHTML;
+    // we won't touch DOM elements which are already there
+    let oldNodes = new Set(container.querySelectorAll(selector + ",form"));
+    window.setTimeout(() => {
+      // we delay our custom sanitization after the browser performed the paste
+      // or drop job, rather than replacing it, in order to avoid interferences
+      // with built-in sanitization
+      try {
+        if (sanitizeExtras(container, oldNodes)) {
+          let t = e.type;
+          console.log(`[NoScript] Sanitized\n<${t}>\n${html}\n</${t}>to\n<${t}>\n${container.innerHTML}\n</${t}>`, container);
         }
       } catch(ex) {
        console.log(ex);
-     }}, 0);
-    }
-  } catch(ex) {
-    console.log(ex);
-  }
+      }
+    }, 0);
+  }, true);
 
   function removeAttribute(node, name, value = node.getAttribute(name)) {
     node.setAttribute(`data-noscript-removed-${name}`, value);
     node.removeAttribute(name);
   }
 
-  function sanitizeExtras(el) {
+  function sanitizeExtras(container,  oldNodes = []) {
     let ret = false;
 
     // remove attributes from forms
-    for (let f of el.getElementsByTagName("form")) {
-      for (let a of f.attributes) {
-        f.removeAttribute(a.name);
-        ret = true;
+    for (let f of container.getElementsByTagName("form")) {
+      if (oldNodes.has(f)) continue;
+      for (let a of [...f.attributes]) {
+        removeAttribute(f, a.name);
       }
     }
 
-    let urlAttributes = ['href', 'to', 'from', 'by', 'values'];
-    let selector = urlAttributes.map(a => `[${a}]`).join(',');
-    for (let node of el.querySelectorAll(selector)) {
+    for (let node of container.querySelectorAll(selector)) {
+      if (oldNodes.has(node)) continue;
       for (let name of urlAttributes) {
         let value = node.getAttribute(name);
         if (/^\W*(?:(?:javascript|data):|https?:[\s\S]+[[(<])/i.test(unescape(value))) {
-          node.setAttribute(`data-noscript-removed-${name}`, value);
-          node.removeAttribute(name);
+          removeAttribute(node, name, value);
           ret = true;
         }
       }
     }
     return ret;
   }
-}, true);
+}
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