add files in the DOM as a source for js/xss-through-dom

Author: erik-krogh

javascript/ql/lib/semmle/javascript/security/dataflow/XssThroughDomCustomizations.qll

@@ -162,6 +162,11 @@ module XssThroughDom {
     }
   }
 
+  /** The `files` property of an `<input />` element */
+  class FilesSource extends Source {
+    FilesSource() { this = DOM::domValueRef().getAPropertyRead("files") }
+  }
+
   /**
    * A module for form inputs seen as sources for xss-through-dom.
    */

javascript/ql/test/query-tests/Security/CWE-079/XssThroughDom/XssThroughDom.expected

@@ -129,6 +129,11 @@ nodes
 | xss-through-dom.js:115:16:115:18 | src |
 | xss-through-dom.js:117:26:117:28 | src |
 | xss-through-dom.js:117:26:117:28 | src |
+| xss-through-dom.js:120:23:120:37 | ev.target.files |
+| xss-through-dom.js:120:23:120:37 | ev.target.files |
+| xss-through-dom.js:120:23:120:40 | ev.target.files[0] |
+| xss-through-dom.js:120:23:120:45 | ev.targ ... 0].name |
+| xss-through-dom.js:120:23:120:45 | ev.targ ... 0].name |
 edges
 | forms.js:8:23:8:28 | values | forms.js:9:31:9:36 | values |
 | forms.js:8:23:8:28 | values | forms.js:9:31:9:36 | values |
@@ -207,6 +212,10 @@ edges
 | xss-through-dom.js:114:11:114:52 | src | xss-through-dom.js:117:26:117:28 | src |
 | xss-through-dom.js:114:17:114:52 | documen ... k").src | xss-through-dom.js:114:11:114:52 | src |
 | xss-through-dom.js:114:17:114:52 | documen ... k").src | xss-through-dom.js:114:11:114:52 | src |
+| xss-through-dom.js:120:23:120:37 | ev.target.files | xss-through-dom.js:120:23:120:40 | ev.target.files[0] |
+| xss-through-dom.js:120:23:120:37 | ev.target.files | xss-through-dom.js:120:23:120:40 | ev.target.files[0] |
+| xss-through-dom.js:120:23:120:40 | ev.target.files[0] | xss-through-dom.js:120:23:120:45 | ev.targ ... 0].name |
+| xss-through-dom.js:120:23:120:40 | ev.target.files[0] | xss-through-dom.js:120:23:120:45 | ev.targ ... 0].name |
 #select
 | forms.js:9:31:9:40 | values.foo | forms.js:8:23:8:28 | values | forms.js:9:31:9:40 | values.foo | $@ is reinterpreted as HTML without escaping meta-characters. | forms.js:8:23:8:28 | values | DOM text |
 | forms.js:12:31:12:40 | values.bar | forms.js:11:24:11:29 | values | forms.js:12:31:12:40 | values.bar | $@ is reinterpreted as HTML without escaping meta-characters. | forms.js:11:24:11:29 | values | DOM text |
@@ -242,3 +251,4 @@ edges
 | xss-through-dom.js:96:17:96:47 | $("#foo ... ].value | xss-through-dom.js:96:17:96:47 | $("#foo ... ].value | xss-through-dom.js:96:17:96:47 | $("#foo ... ].value | $@ is reinterpreted as HTML without escaping meta-characters. | xss-through-dom.js:96:17:96:47 | $("#foo ... ].value | DOM text |
 | xss-through-dom.js:109:31:109:70 | "<a src ... oo</a>" | xss-through-dom.js:109:45:109:55 | this.el.src | xss-through-dom.js:109:31:109:70 | "<a src ... oo</a>" | $@ is reinterpreted as HTML without escaping meta-characters. | xss-through-dom.js:109:45:109:55 | this.el.src | DOM text |
 | xss-through-dom.js:115:16:115:18 | src | xss-through-dom.js:114:17:114:52 | documen ... k").src | xss-through-dom.js:115:16:115:18 | src | $@ is reinterpreted as HTML without escaping meta-characters. | xss-through-dom.js:114:17:114:52 | documen ... k").src | DOM text |
+| xss-through-dom.js:120:23:120:45 | ev.targ ... 0].name | xss-through-dom.js:120:23:120:37 | ev.target.files | xss-through-dom.js:120:23:120:45 | ev.targ ... 0].name | $@ is reinterpreted as HTML without escaping meta-characters. | xss-through-dom.js:120:23:120:37 | ev.target.files | DOM text |

javascript/ql/test/query-tests/Security/CWE-079/XssThroughDom/xss-through-dom.js

@@ -115,4 +115,8 @@ class Sub extends Super {
 	$("#id").html(src); // NOT OK.
 
     $("#id").attr("src", src); // OK
+
+    $("input.foo")[0].onchange = function (ev) {
+        $("#id").html(ev.target.files[0].name); // NOT OK.
+    }
 })();