1
// Copyright 2013 The Closure Library Authors. All Rights Reserved.
2
//
3
// Licensed under the Apache License, Version 2.0 (the "License");
4
// you may not use this file except in compliance with the License.
5
// You may obtain a copy of the License at
6
//
7
//      http://www.apache.org/licenses/LICENSE-2.0
8
//
9
// Unless required by applicable law or agreed to in writing, software
10
// distributed under the License is distributed on an "AS-IS" BASIS,
11
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12
// See the License for the specific language governing permissions and
13
// limitations under the License.
14

15
/**
16
 * @fileoverview Transitional utilities to unsafely trust random strings as
17
 * goog.html types. Intended for temporary use when upgrading a library that
18
 * used to accept plain strings to use safe types, but where it's not
19
 * practical to transitively update callers.
20
 *
21
 * IMPORTANT: No new code should use the conversion functions in this file,
22
 * they are intended for refactoring old code to use goog.html types. New code
23
 * should construct goog.html types via their APIs, template systems or
24
 * sanitizers. If that’s not possible it should use
25
 * goog.html.uncheckedconversions and undergo security review.
26

27
 *
28
 * The semantics of the conversions in goog.html.legacyconversions are very
29
 * different from the ones provided by goog.html.uncheckedconversions. The
30
 * latter are for use in code where it has been established through manual
31
 * security review that the value produced by a piece of code will always
32
 * satisfy the SafeHtml contract (e.g., the output of a secure HTML sanitizer).
33
 * In uses of goog.html.legacyconversions, this guarantee is not given -- the
34
 * value in question originates in unreviewed legacy code and there is no
35
 * guarantee that it satisfies the SafeHtml contract.
36
 *
37
 * There are only three valid uses of legacyconversions:
38
 *
39
 * 1. Introducing a goog.html version of a function which currently consumes
40
 * string and passes that string to a DOM API which can execute script - and
41
 * hence cause XSS - like innerHTML. For example, Dialog might expose a
42
 * setContent method which takes a string and sets the innerHTML property of
43
 * an element with it. In this case a setSafeHtmlContent function could be
44
 * added, consuming goog.html.SafeHtml instead of string, and using
45
 * goog.dom.safe.setInnerHtml instead of directly setting innerHTML.
46
 * setContent could then internally use legacyconversions to create a SafeHtml
47
 * from string and pass the SafeHtml to setSafeHtmlContent. In this scenario
48
 * remember to document the use of legacyconversions in the modified setContent
49
 * and consider deprecating it as well.
50
 *
51
 * 2. Automated refactoring of application code which handles HTML as string
52
 * but needs to call a function which only takes goog.html types. For example,
53
 * in the Dialog scenario from (1) an alternative option would be to refactor
54
 * setContent to accept goog.html.SafeHtml instead of string and then refactor
55
 * all current callers to use legacyconversions to pass SafeHtml. This is
56
 * generally preferable to (1) because it keeps the library clean of
57
 * legacyconversions, and makes code sites in application code that are
58
 * potentially vulnerable to XSS more apparent.
59
 *
60
 * 3. Old code which needs to call APIs which consume goog.html types and for
61
 * which it is prohibitively expensive to refactor to use goog.html types.
62
 * Generally, this is code where safety from XSS is either hopeless or
63
 * unimportant.
64
 *
65
 * @visibility {//closure/goog/html:approved_for_legacy_conversion}
66
 * @visibility {//closure/goog/bin/sizetests:__pkg__}
67
 */
68

69

70
goog.provide('goog.html.legacyconversions');
71

72
goog.require('goog.html.SafeHtml');
73
goog.require('goog.html.SafeStyle');
74
goog.require('goog.html.SafeStyleSheet');
75
goog.require('goog.html.SafeUrl');
76
goog.require('goog.html.TrustedResourceUrl');
77

78

79
/**
80
 * Performs an "unchecked conversion" from string to SafeHtml for legacy API
81
 * purposes.
82
 *
83
 * Please read fileoverview documentation before using.
84
 *
85
 * @param {string} html A string to be converted to SafeHtml.
86
 * @return {!goog.html.SafeHtml} The value of html, wrapped in a SafeHtml
87
 *     object.
88
 */
89
goog.html.legacyconversions.safeHtmlFromString = function(html) {
90
  goog.html.legacyconversions.reportCallback_();
91
  return goog.html.SafeHtml.createSafeHtmlSecurityPrivateDoNotAccessOrElse(
92
      html, null /* dir */);
93
};
94

95

96
/**
97
 * Performs an "unchecked conversion" from string to SafeStyle for legacy API
98
 * purposes.
99
 *
100
 * Please read fileoverview documentation before using.
101
 *
102
 * @param {string} style A string to be converted to SafeStyle.
103
 * @return {!goog.html.SafeStyle} The value of style, wrapped in a SafeStyle
104
 *     object.
105
 */
106
goog.html.legacyconversions.safeStyleFromString = function(style) {
107
  goog.html.legacyconversions.reportCallback_();
108
  return goog.html.SafeStyle.createSafeStyleSecurityPrivateDoNotAccessOrElse(
109
      style);
110
};
111

112

113
/**
114
 * Performs an "unchecked conversion" from string to SafeStyleSheet for legacy
115
 * API purposes.
116
 *
117
 * Please read fileoverview documentation before using.
118
 *
119
 * @param {string} styleSheet A string to be converted to SafeStyleSheet.
120
 * @return {!goog.html.SafeStyleSheet} The value of style sheet, wrapped in
121
 *     a SafeStyleSheet object.
122
 */
123
goog.html.legacyconversions.safeStyleSheetFromString = function(styleSheet) {
124
  goog.html.legacyconversions.reportCallback_();
125
  return goog.html.SafeStyleSheet
126
      .createSafeStyleSheetSecurityPrivateDoNotAccessOrElse(styleSheet);
127
};
128

129

130
/**
131
 * Performs an "unchecked conversion" from string to SafeUrl for legacy API
132
 * purposes.
133
 *
134
 * Please read fileoverview documentation before using.
135
 *
136
 * @param {string} url A string to be converted to SafeUrl.
137
 * @return {!goog.html.SafeUrl} The value of url, wrapped in a SafeUrl
138
 *     object.
139
 */
140
goog.html.legacyconversions.safeUrlFromString = function(url) {
141
  goog.html.legacyconversions.reportCallback_();
142
  return goog.html.SafeUrl.createSafeUrlSecurityPrivateDoNotAccessOrElse(url);
143
};
144

145

146
/**
147
 * Performs an "unchecked conversion" from string to TrustedResourceUrl for
148
 * legacy API purposes.
149
 *
150
 * Please read fileoverview documentation before using.
151
 *
152
 * @param {string} url A string to be converted to TrustedResourceUrl.
153
 * @return {!goog.html.TrustedResourceUrl} The value of url, wrapped in a
154
 *     TrustedResourceUrl object.
155
 */
156
goog.html.legacyconversions.trustedResourceUrlFromString = function(url) {
157
  goog.html.legacyconversions.reportCallback_();
158
  return goog.html.TrustedResourceUrl
159
      .createTrustedResourceUrlSecurityPrivateDoNotAccessOrElse(url);
160
};
161

162
/**
163
 * @private {function(): undefined}
164
 */
165
goog.html.legacyconversions.reportCallback_ = goog.nullFunction;
166

167

168
/**
169
 * Sets a function that will be called every time a legacy conversion is
170
 * performed. The function is called with no parameters but it can use
171
 * goog.debug.getStacktrace to get a stacktrace.
172
 *
173
 * @param {function(): undefined} callback Error callback as defined above.
174
 */
175
goog.html.legacyconversions.setReportCallback = function(callback) {
176
  goog.html.legacyconversions.reportCallback_ = callback;
177
};
178

179