fix($compile): sanitize values bound to a[href]

1 files changed, 52 insertions, 6 deletions

diff --git a/src/ng/compile.js b/src/ng/compile.js
index 2ed34f73..84a9c3ca 100644
--- a/src/ng/compile.js
+++ b/src/ng/compile.js
@@ -155,7 +155,8 @@ function $CompileProvider($provide) {
       Suffix = 'Directive',
       COMMENT_DIRECTIVE_REGEXP = /^\s*directive\:\s*([\d\w\-_]+)\s+(.*)$/,
       CLASS_DIRECTIVE_REGEXP = /(([\d\w\-_]+)(?:\:([^;]+))?;?)/,
-      MULTI_ROOT_TEMPLATE_ERROR = 'Template must have exactly one root element. was: ';
+      MULTI_ROOT_TEMPLATE_ERROR = 'Template must have exactly one root element. was: ',
+      urlSanitizationWhitelist = /^\s*(https?|ftp|mailto):/;
 
 
   /**
@@ -209,11 +210,41 @@ function $CompileProvider($provide) {
   };
 
 
+  /**
+   * @ngdoc function
+   * @name ng.$compileProvider#urlSanitizationWhitelist
+   * @methodOf ng.$compileProvider
+   * @function
+   *
+   * @description
+   * Retrieves or overrides the default regular expression that is used for whitelisting of safe
+   * urls during a[href] sanitization.
+   *
+   * The sanitization is a security measure aimed at prevent XSS attacks via html links.
+   *
+   * Any url about to be assigned to a[href] via data-binding is first normalized and turned into an
+   * absolute url. Afterwards the url is matched against the `urlSanitizationWhitelist` regular
+   * expression. If a match is found the original url is written into the dom. Otherwise the
+   * absolute url is prefixed with `'unsafe:'` string and only then it is written into the DOM.
+   *
+   * @param {RegExp=} regexp New regexp to whitelist urls with.
+   * @returns {RegExp|ng.$compileProvider} Current RegExp if called without value or self for
+   *    chaining otherwise.
+   */
+  this.urlSanitizationWhitelist = function(regexp) {
+    if (isDefined(regexp)) {
+      urlSanitizationWhitelist = regexp;
+      return this;
+    }
+    return urlSanitizationWhitelist;
+  };
+
+
   this.$get = [
             '$injector', '$interpolate', '$exceptionHandler', '$http', '$templateCache', '$parse',
-            '$controller', '$rootScope',
+            '$controller', '$rootScope', '$document',
     function($injector,   $interpolate,   $exceptionHandler,   $http,   $templateCache,   $parse,
-             $controller,   $rootScope) {
+             $controller,   $rootScope,   $document) {
 
     var Attributes = function(element, attr) {
       this.$$element = element;
@@ -235,7 +266,8 @@ function $CompileProvider($provide) {
        */
       $set: function(key, value, writeAttr, attrName) {
         var booleanKey = getBooleanAttrName(this.$$element[0], key),
-            $$observers = this.$$observers;
+            $$observers = this.$$observers,
+            normalizedVal;
 
         if (booleanKey) {
           this.$$element.prop(key, value);
@@ -254,6 +286,19 @@ function $CompileProvider($provide) {
           }
         }
 
+
+        // sanitize a[href] values
+        if (nodeName_(this.$$element[0]) === 'A' && key === 'href') {
+          urlSanitizationNode.setAttribute('href', value);
+
+          // href property always returns normalized absolute url, so we can match against that
+          normalizedVal = urlSanitizationNode.href;
+          if (!normalizedVal.match(urlSanitizationWhitelist)) {
+            this[key] = value = 'unsafe:' + normalizedVal;
+          }
+        }
+
+
         if (writeAttr !== false) {
           if (value === null || value === undefined) {
             this.$$element.removeAttr(attrName);
@@ -297,7 +342,8 @@ function $CompileProvider($provide) {
       }
     };
 
-    var startSymbol = $interpolate.startSymbol(),
+    var urlSanitizationNode = $document[0].createElement('a'),
+        startSymbol = $interpolate.startSymbol(),
         endSymbol = $interpolate.endSymbol(),
         denormalizeTemplate = (startSymbol == '{{' || endSymbol  == '}}')
             ? identity
@@ -1025,10 +1071,10 @@ function $CompileProvider($provide) {
     function addAttrInterpolateDirective(node, directives, value, name) {
       var interpolateFn = $interpolate(value, true);
 
-
       // no interpolation found -> ignore
       if (!interpolateFn) return;
 
+
       directives.push({
         priority: 100,
         compile: valueFn(function attrInterpolateLinkFn(scope, element, attr) {