From bbd1384acbe7e52c21f89af69f2dc391c95dbf54 Mon Sep 17 00:00:00 2001
From: PercussiveElbow <PercussiveElbow@users.noreply.github.com>
Date: Tue, 27 Oct 2020 01:34:51 +0000
Subject: [PATCH] XSS and redirect fixes with test cases

---
 app/Entities/Managers/PageContent.php | 18 ++++++++
 tests/Entity/PageContentTest.php      | 66 +++++++++++++++++++++++++++
 2 files changed, 84 insertions(+)

diff --git a/app/Entities/Managers/PageContent.php b/app/Entities/Managers/PageContent.php
index a787e5d99..7338a36b3 100644
--- a/app/Entities/Managers/PageContent.php
+++ b/app/Entities/Managers/PageContent.php
@@ -296,6 +296,24 @@ class PageContent
             $scriptElem->parentNode->removeChild($scriptElem);
         }
 
+        // Remove clickable links to JavaScript URI
+        $badLinks = $xPath->query('//*[contains(@href, \'javascript:\')]');
+        foreach ($badLinks as $badLink) {
+            $badLink->parentNode->removeChild($badLink);
+        }
+
+        // Remove forms with calls to JavaScript URI
+        $badForms = $xPath->query('//*[contains(@action, \'javascript:\')] | //*[contains(@formaction, \'javascript:\')]');
+        foreach ($badForms as $badForm) {
+            $badForm->parentNode->removeChild($badForm);
+        }
+
+        // Remove meta tag to prevent external redirects
+        $metaTags = $xPath->query('//meta[contains(@content, \'url\')]');
+        foreach ($metaTags as $metaTag) {
+            $metaTag->parentNode->removeChild($metaTag);
+        }
+
         // Remove data or JavaScript iFrames
         $badIframes = $xPath->query('//*[contains(@src, \'data:\')] | //*[contains(@src, \'javascript:\')] | //*[@srcdoc]');
         foreach ($badIframes as $badIframe) {
diff --git a/tests/Entity/PageContentTest.php b/tests/Entity/PageContentTest.php
index 99547fd17..e97df2c7e 100644
--- a/tests/Entity/PageContentTest.php
+++ b/tests/Entity/PageContentTest.php
@@ -159,6 +159,72 @@ class PageContentTest extends TestCase
 
     }
 
+    public function test_javascript_uri_links_are_removed()
+    {
+        $checks = [
+            '<a id="xss" href="javascript:alert(document.cookie)>Click me</a>',
+            '<a id="xss" href="javascript: alert(document.cookie)>Click me</a>'
+        ];
+
+        $this->asEditor();
+        $page = Page::first();
+
+        foreach ($checks as $check) {
+            $page->html = $check;
+            $page->save();
+
+            $pageView = $this->get($page->getUrl());
+            $pageView->assertStatus(200);
+            $pageView->assertElementNotContains('.page-content', '<a id="xss">');
+            $pageView->assertElementNotContains('.page-content', 'href=javascript:');
+        }
+    }
+    public function test_form_actions_with_javascript_are_removed()
+    {
+        $checks = [
+            '<form><input id="xss" type=submit formaction=javascript:alert(document.domain) value=Submit><input></form>',
+            '<form ><button id="xss" formaction=javascript:alert(document.domain)>Click me</button></form>',
+            '<form id="xss" action=javascript:alert(document.domain)><input type=submit value=Submit></form>'
+        ];
+
+        $this->asEditor();
+        $page = Page::first();
+
+        foreach ($checks as $check) {
+            $page->html = $check;
+            $page->save();
+
+            $pageView = $this->get($page->getUrl());
+            $pageView->assertStatus(200);
+            $pageView->assertElementNotContains('.page-content', '<button id="xss"');
+            $pageView->assertElementNotContains('.page-content', '<input id="xss"');
+            $pageView->assertElementNotContains('.page-content', '<form id="xss"');
+            $pageView->assertElementNotContains('.page-content', 'action=javascript:');
+            $pageView->assertElementNotContains('.page-content', 'formaction=javascript:');
+        }
+    }
+    
+    public function test_metadata_redirects_are_removed()
+    {
+        $checks = [
+            '<meta http-equiv="refresh" content="0; url=//external_url">',
+        ];
+
+        $this->asEditor();
+        $page = Page::first();
+
+        foreach ($checks as $check) {
+            $page->html = $check;
+            $page->save();
+
+            $pageView = $this->get($page->getUrl());
+            $pageView->assertStatus(200);
+            $pageView->assertElementNotContains('.page-content', '<meta>');
+            $pageView->assertElementNotContains('.page-content', '</meta>');
+            $pageView->assertElementNotContains('.page-content', 'content=');
+            $pageView->assertElementNotContains('.page-content', 'external_url');
+        }
+    }
     public function test_page_inline_on_attributes_removed_by_default()
     {
         $this->asEditor();