FIX: display tables in posts history diff (#6032)

app/assets/javascripts/discourse/controllers/history.js.es6

@@ -2,9 +2,8 @@ import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { categoryBadgeHTML } from "discourse/helpers/category-link";
 import computed from "ember-addons/ember-computed-decorators";
 import { propertyGreaterThan, propertyLessThan } from "discourse/lib/computed";
-import { on } from "ember-addons/ember-computed-decorators";
-import { default as WhiteLister } from "pretty-text/white-lister";
-import { sanitize } from "pretty-text/sanitizer";
+import { on, observes } from "ember-addons/ember-computed-decorators";
+import { sanitizeAsync } from "discourse/lib/text";
 
 function customTagArray(fieldName) {
   return function() {
@@ -246,15 +245,23 @@ export default Ember.Controller.extend(ModalFunctionality, {
     return this.get("model.title_changes." + viewMode);
   },
 
-  @computed("viewMode", "model.body_changes")
-  bodyDiff(viewMode) {
+  @observes("viewMode", "model.body_changes")
+  bodyDiffChanged() {
+    const viewMode = this.get("viewMode");
     const html = this.get(`model.body_changes.${viewMode}`);
     if (viewMode === "side_by_side_markdown") {
-      return html;
+      this.set("bodyDiff", html);
     } else {
-      const whiteLister = new WhiteLister({ features: { editHistory: true } });
-      whiteLister.whiteListFeature("editHistory", { custom: () => true });
-      return sanitize(html, whiteLister);
+      const opts = {
+        features: { editHistory: true },
+        whiteListed: {
+          editHistory: { custom: (tag, attr) => attr === "class" }
+        }
+      };
+
+      return sanitizeAsync(html, opts).then(result =>
+        this.set("bodyDiff", result)
+      );
     }
   },
 

app/assets/javascripts/discourse/lib/text.js.es6

@@ -25,25 +25,39 @@ function getOpts(opts) {
 
 // Use this to easily create a pretty text instance with proper options
 export function cook(text, options) {
-  return new Handlebars.SafeString(new PrettyText(getOpts(options)).cook(text));
+  return new Handlebars.SafeString(createPrettyText(options).cook(text));
 }
 
 // everything should eventually move to async API and this should be renamed
 // cook
 export function cookAsync(text, options) {
-  if (Discourse.MarkdownItURL) {
-    return loadScript(Discourse.MarkdownItURL)
-      .then(() => cook(text, options))
-      .catch(e => Ember.Logger.error(e));
-  } else {
-    return Ember.RSVP.Promise.resolve(cook(text));
-  }
+  return loadMarkdownIt().then(() => cook(text, options));
 }
 
 export function sanitize(text, options) {
   return textSanitize(text, new WhiteLister(options));
 }
 
+export function sanitizeAsync(text, options) {
+  return new loadMarkdownIt().then(() => {
+    return createPrettyText(options).sanitize(text);
+  });
+}
+
+function loadMarkdownIt() {
+  if (Discourse.MarkdownItURL) {
+    return loadScript(Discourse.MarkdownItURL).catch(e =>
+      Ember.Logger.error(e)
+    );
+  } else {
+    return Ember.RSVP.Promise.resolve();
+  }
+}
+
+function createPrettyText(options) {
+  return new PrettyText(getOpts(options));
+}
+
 function emojiOptions() {
   const siteSettings = Discourse.__container__.lookup("site-settings:main");
   if (!siteSettings.enable_emoji) {

app/assets/javascripts/pretty-text/engines/discourse-markdown-it.js.es6

@@ -210,6 +210,10 @@ export function setup(opts, siteSettings, state) {
     }
   });
 
+  Object.entries(state.whiteListed || {}).forEach(entry => {
+    whiteListed.push(entry);
+  });
+
   optionCallbacks.forEach(([, callback]) => {
     callback(opts, siteSettings, state);
   });

test/javascripts/controllers/history-test.js.es6

@@ -22,10 +22,59 @@ QUnit.test("displayEdit", function(assert) {
   );
 
   HistoryController.set("model.current_revision", 2);
-
   assert.equal(
     HistoryController.get("displayEdit"),
     false,
     "it should only display the edit button on the latest revision"
   );
+
+  const html = `<div class="revision-content">
+  <p><img src="/uploads/default/original/1X/6b963ffc13cb0c053bbb90c92e99d4fe71b286ef.jpg" alt="" class="diff-del"><img/src=x onerror=alert(document.domain)>" width="276" height="183"></p>
+</div>
+<table background="javascript:alert(\"HACKEDXSS\")">
+  <thead>
+    <tr>
+      <th>Column</th>
+      <th style="text-align:left">Test</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td background="javascript:alert('HACKEDXSS')">Osama</td>
+      <td style="text-align:right">Testing</td>
+    </tr>
+  </tbody>
+</table>`;
+
+  const expectedOutput = `<div class="revision-content">
+  <p><img src="/uploads/default/original/1X/6b963ffc13cb0c053bbb90c92e99d4fe71b286ef.jpg" alt class="diff-del">" width="276" height="183"&gt;</p>
+</div>
+<table>
+  <thead>
+    <tr>
+      <th>Column</th>
+      <th style="text-align:left">Test</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td>Osama</td>
+      <td style="text-align:right">Testing</td>
+    </tr>
+  </tbody>
+</table>`;
+
+  HistoryController.setProperties({
+    viewMode: "side_by_side",
+    model: {
+      body_changes: {
+        side_by_side: html
+      }
+    }
+  });
+
+  HistoryController.bodyDiffChanged().then(() => {
+    const output = HistoryController.get("bodyDiff");
+    assert.equal(output, expectedOutput, "it keeps safe HTML");
+  });
 });