Desktop: Security: Protect against certain types of DOM clobbering

attacks

packages/app-cli/tests/md_to_html/sanitize_22.html

@@ -0,0 +1,2 @@
+<img src="test/" class="jop-noMdConv"/>
+<img src="http://example.com/test.png" class="jop-noMdConv"/>

packages/app-cli/tests/md_to_html/sanitize_22.md

@@ -0,0 +1,3 @@
+<img name=getElementById src=test/>
+
+<IMG NAME="getElementById" SRC="http://example.com/test.png">

packages/renderer/htmlUtils.ts

@@ -308,6 +308,12 @@ class HtmlUtils {
 					attrs['href'] = '#';
 				}
 
+				// Allowing the 'name' attribute allows an attacker to overwrite
+				// DOM methods (e.g. getElementById) with elements.
+				if ('name' in attrs) {
+					delete attrs['name'];
+				}
+
 				// We need to clear any such attribute, otherwise it will
 				// make any arbitrary link open within the application.
 				if ('data-from-md' in attrs) {