| // Copyright 2013 The Closure Library Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS-IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| /** |
| * @fileoverview The TrustedResourceUrl type and its builders. |
| * |
| * TODO(user): Link to document stating type contract. |
| */ |
| |
| goog.provide('goog.html.TrustedResourceUrl'); |
| |
| goog.require('goog.asserts'); |
| goog.require('goog.i18n.bidi.Dir'); |
| goog.require('goog.i18n.bidi.DirectionalString'); |
| goog.require('goog.string.Const'); |
| goog.require('goog.string.TypedString'); |
| |
| |
| |
| /** |
| * A URL which is under application control and from which script, CSS, and |
| * other resources that represent executable code, can be fetched. |
| * |
| * Given that the URL can only be constructed from strings under application |
| * control and is used to load resources, bugs resulting in a malformed URL |
| * should not have a security impact and are likely to be easily detectable |
| * during testing. Given the wide number of non-RFC compliant URLs in use, |
| * stricter validation could prevent some applications from being able to use |
| * this type. |
| * |
| * Instances of this type must be created via the factory method, |
| * ({@code goog.html.TrustedResourceUrl.fromConstant}), and not by invoking its |
| * constructor. The constructor intentionally takes no parameters and the type |
| * is immutable; hence only a default instance corresponding to the empty |
| * string can be obtained via constructor invocation. |
| * |
| * @see goog.html.TrustedResourceUrl#fromConstant |
| * @constructor |
| * @final |
| * @struct |
| * @implements {goog.i18n.bidi.DirectionalString} |
| * @implements {goog.string.TypedString} |
| */ |
| goog.html.TrustedResourceUrl = function() { |
| /** |
| * The contained value of this TrustedResourceUrl. The field has a purposely |
| * ugly name to make (non-compiled) code that attempts to directly access this |
| * field stand out. |
| * @private {string} |
| */ |
| this.privateDoNotAccessOrElseTrustedResourceUrlWrappedValue_ = ''; |
| |
| /** |
| * A type marker used to implement additional run-time type checking. |
| * @see goog.html.TrustedResourceUrl#unwrap |
| * @const |
| * @private |
| */ |
| this.TRUSTED_RESOURCE_URL_TYPE_MARKER_GOOG_HTML_SECURITY_PRIVATE_ = |
| goog.html.TrustedResourceUrl.TYPE_MARKER_GOOG_HTML_SECURITY_PRIVATE_; |
| }; |
| |
| |
| /** |
| * @override |
| * @const |
| */ |
| goog.html.TrustedResourceUrl.prototype.implementsGoogStringTypedString = true; |
| |
| |
| /** |
| * Returns this TrustedResourceUrl's value as a string. |
| * |
| * IMPORTANT: In code where it is security relevant that an object's type is |
| * indeed {@code TrustedResourceUrl}, use |
| * {@code goog.html.TrustedResourceUrl.unwrap} instead of this method. If in |
| * doubt, assume that it's security relevant. In particular, note that |
| * goog.html functions which return a goog.html type do not guarantee that |
| * the returned instance is of the right type. For example: |
| * |
| * <pre> |
| * var fakeSafeHtml = new String('fake'); |
| * fakeSafeHtml.__proto__ = goog.html.SafeHtml.prototype; |
| * var newSafeHtml = goog.html.SafeHtml.htmlEscape(fakeSafeHtml); |
| * // newSafeHtml is just an alias for fakeSafeHtml, it's passed through by |
| * // goog.html.SafeHtml.htmlEscape() as fakeSafeHtml instanceof |
| * // goog.html.SafeHtml. |
| * </pre> |
| * |
| * @see goog.html.TrustedResourceUrl#unwrap |
| * @override |
| */ |
| goog.html.TrustedResourceUrl.prototype.getTypedStringValue = function() { |
| return this.privateDoNotAccessOrElseTrustedResourceUrlWrappedValue_; |
| }; |
| |
| |
| /** |
| * @override |
| * @const |
| */ |
| goog.html.TrustedResourceUrl.prototype.implementsGoogI18nBidiDirectionalString = |
| true; |
| |
| |
| /** |
| * Returns this URLs directionality, which is always {@code LTR}. |
| * @override |
| */ |
| goog.html.TrustedResourceUrl.prototype.getDirection = function() { |
| return goog.i18n.bidi.Dir.LTR; |
| }; |
| |
| |
| if (goog.DEBUG) { |
| /** |
| * Returns a debug string-representation of this value. |
| * |
| * To obtain the actual string value wrapped in a TrustedResourceUrl, use |
| * {@code goog.html.TrustedResourceUrl.unwrap}. |
| * |
| * @see goog.html.TrustedResourceUrl#unwrap |
| * @override |
| */ |
| goog.html.TrustedResourceUrl.prototype.toString = function() { |
| return 'TrustedResourceUrl{' + |
| this.privateDoNotAccessOrElseTrustedResourceUrlWrappedValue_ + '}'; |
| }; |
| } |
| |
| |
| /** |
| * Performs a runtime check that the provided object is indeed a |
| * TrustedResourceUrl object, and returns its value. |
| * |
| * @param {!goog.html.TrustedResourceUrl} trustedResourceUrl The object to |
| * extract from. |
| * @return {string} The trustedResourceUrl object's contained string, unless |
| * the run-time type check fails. In that case, {@code unwrap} returns an |
| * innocuous string, or, if assertions are enabled, throws |
| * {@code goog.asserts.AssertionError}. |
| */ |
| goog.html.TrustedResourceUrl.unwrap = function(trustedResourceUrl) { |
| // Perform additional Run-time type-checking to ensure that |
| // trustedResourceUrl is indeed an instance of the expected type. This |
| // provides some additional protection against security bugs due to |
| // application code that disables type checks. |
| // Specifically, the following checks are performed: |
| // 1. The object is an instance of the expected type. |
| // 2. The object is not an instance of a subclass. |
| // 3. The object carries a type marker for the expected type. "Faking" an |
| // object requires a reference to the type marker, which has names intended |
| // to stand out in code reviews. |
| if (trustedResourceUrl instanceof goog.html.TrustedResourceUrl && |
| trustedResourceUrl.constructor === goog.html.TrustedResourceUrl && |
| trustedResourceUrl |
| .TRUSTED_RESOURCE_URL_TYPE_MARKER_GOOG_HTML_SECURITY_PRIVATE_ === |
| goog.html.TrustedResourceUrl |
| .TYPE_MARKER_GOOG_HTML_SECURITY_PRIVATE_) { |
| return trustedResourceUrl |
| .privateDoNotAccessOrElseTrustedResourceUrlWrappedValue_; |
| } else { |
| goog.asserts.fail('expected object of type TrustedResourceUrl, got \'' + |
| trustedResourceUrl + '\''); |
| return 'type_error:TrustedResourceUrl'; |
| |
| } |
| }; |
| |
| |
| /** |
| * Creates a TrustedResourceUrl object from a compile-time constant string. |
| * |
| * Compile-time constant strings are inherently program-controlled and hence |
| * trusted. |
| * |
| * @param {!goog.string.Const} url A compile-time-constant string from which to |
| * create a TrustedResourceUrl. |
| * @return {!goog.html.TrustedResourceUrl} A TrustedResourceUrl object |
| * initialized to {@code url}. |
| */ |
| goog.html.TrustedResourceUrl.fromConstant = function(url) { |
| return goog.html.TrustedResourceUrl |
| .createTrustedResourceUrlSecurityPrivateDoNotAccessOrElse( |
| goog.string.Const.unwrap(url)); |
| }; |
| |
| |
| /** |
| * Type marker for the TrustedResourceUrl type, used to implement additional |
| * run-time type checking. |
| * @const |
| * @private |
| */ |
| goog.html.TrustedResourceUrl.TYPE_MARKER_GOOG_HTML_SECURITY_PRIVATE_ = {}; |
| |
| |
| /** |
| * Package-internal utility method to create TrustedResourceUrl instances. |
| * |
| * @param {string} url The string to initialize the TrustedResourceUrl object |
| * with. |
| * @return {!goog.html.TrustedResourceUrl} The initialized TrustedResourceUrl |
| * object. |
| * @package |
| */ |
| goog.html.TrustedResourceUrl. |
| createTrustedResourceUrlSecurityPrivateDoNotAccessOrElse = function(url) { |
| var trustedResourceUrl = new goog.html.TrustedResourceUrl(); |
| trustedResourceUrl.privateDoNotAccessOrElseTrustedResourceUrlWrappedValue_ = |
| url; |
| return trustedResourceUrl; |
| }; |