src/ngSanitize/sanitize.js
'use strict';
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Any commits to this file should be reviewed with security in mind. *
* Changes to this file can potentially create security vulnerabilities. *
* An approval from 2 Core members with history of modifying *
* this file is required. *
* *
* Does the change somehow allow for arbitrary javascript to be executed? *
* Or allows for someone to change the prototype of built-in objects? *
* Or gives undesired access to variables likes document or window? *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
var $sanitizeMinErr = angular.$$minErr('$sanitize');
var bind;
var extend;
var forEach;
var isArray;
var isDefined;
var lowercase;
var noop;
var nodeContains;
var htmlParser;
var htmlSanitizeWriter;
/**
* @ngdoc module
* @name ngSanitize
* @description
*
* The `ngSanitize` module provides functionality to sanitize HTML.
*
* See {@link ngSanitize.$sanitize `$sanitize`} for usage.
*/
/**
* @ngdoc service
* @name $sanitize
* @kind function
*
* @description
* Sanitizes an html string by stripping all potentially dangerous tokens.
*
* The input is sanitized by parsing the HTML into tokens. All safe tokens (from a trusted URI list) are
* then serialized back to a properly escaped HTML string. This means that no unsafe input can make
* it into the returned string.
*
* The trusted URIs for URL sanitization of attribute values is configured using the functions
* `aHrefSanitizationTrustedUrlList` and `imgSrcSanitizationTrustedUrlList` of {@link $compileProvider}.
*
* The input may also contain SVG markup if this is enabled via {@link $sanitizeProvider}.
*
* @param {string} html HTML input.
* @returns {string} Sanitized HTML.
*
* @example
<example module="sanitizeExample" deps="angular-sanitize.js" name="sanitize-service">
<file name="index.html">
<script>
angular.module('sanitizeExample', ['ngSanitize'])
.controller('ExampleController', ['$scope', '$sce', function($scope, $sce) {
$scope.snippet =
'<p style="color:blue">an html\n' +
'<em onmouseover="this.textContent=\'PWN3D!\'">click here</em>\n' +
'snippet</p>';
$scope.deliberatelyTrustDangerousSnippet = function() {
return $sce.trustAsHtml($scope.snippet);
};
}]);
</script>
<div ng-controller="ExampleController">
Snippet: <textarea ng-model="snippet" cols="60" rows="3"></textarea>
<table>
<tr>
<td>Directive</td>
<td>How</td>
<td>Source</td>
<td>Rendered</td>
</tr>
<tr id="bind-html-with-sanitize">
<td>ng-bind-html</td>
<td>Automatically uses $sanitize</td>
<td><pre><div ng-bind-html="snippet"><br/></div></pre></td>
<td><div ng-bind-html="snippet"></div></td>
</tr>
<tr id="bind-html-with-trust">
<td>ng-bind-html</td>
<td>Bypass $sanitize by explicitly trusting the dangerous value</td>
<td>
<pre><div ng-bind-html="deliberatelyTrustDangerousSnippet()">
</div></pre>
</td>
<td><div ng-bind-html="deliberatelyTrustDangerousSnippet()"></div></td>
</tr>
<tr id="bind-default">
<td>ng-bind</td>
<td>Automatically escapes</td>
<td><pre><div ng-bind="snippet"><br/></div></pre></td>
<td><div ng-bind="snippet"></div></td>
</tr>
</table>
</div>
</file>
<file name="protractor.js" type="protractor">
it('should sanitize the html snippet by default', function() {
expect(element(by.css('#bind-html-with-sanitize div')).getAttribute('innerHTML')).
toBe('<p>an html\n<em>click here</em>\nsnippet</p>');
});
it('should inline raw snippet if bound to a trusted value', function() {
expect(element(by.css('#bind-html-with-trust div')).getAttribute('innerHTML')).
toBe("<p style=\"color:blue\">an html\n" +
"<em onmouseover=\"this.textContent='PWN3D!'\">click here</em>\n" +
"snippet</p>");
});
it('should escape snippet without any filter', function() {
expect(element(by.css('#bind-default div')).getAttribute('innerHTML')).
toBe("<p style=\"color:blue\">an html\n" +
"<em onmouseover=\"this.textContent='PWN3D!'\">click here</em>\n" +
"snippet</p>");
});
it('should update', function() {
element(by.model('snippet')).clear();
element(by.model('snippet')).sendKeys('new <b onclick="alert(1)">text</b>');
expect(element(by.css('#bind-html-with-sanitize div')).getAttribute('innerHTML')).
toBe('new <b>text</b>');
expect(element(by.css('#bind-html-with-trust div')).getAttribute('innerHTML')).toBe(
'new <b onclick="alert(1)">text</b>');
expect(element(by.css('#bind-default div')).getAttribute('innerHTML')).toBe(
"new <b onclick=\"alert(1)\">text</b>");
});
</file>
</example>
*/
/**
* @ngdoc provider
* @name $sanitizeProvider
* @this
*
* @description
* Creates and configures {@link $sanitize} instance.
*/
function $SanitizeProvider() {
var hasBeenInstantiated = false;
var svgEnabled = false;
this.$get = ['$$sanitizeUri', function($$sanitizeUri) {
hasBeenInstantiated = true;
if (svgEnabled) {
extend(validElements, svgElements);
}
return function(html) {
var buf = [];
htmlParser(html, htmlSanitizeWriter(buf, function(uri, isImage) {
return !/^unsafe:/.test($$sanitizeUri(uri, isImage));
}));
return buf.join('');
};
}];
/**
* @ngdoc method
* @name $sanitizeProvider#enableSvg
* @kind function
*
* @description
* Enables a subset of svg to be supported by the sanitizer.
*
* <div class="alert alert-warning">
* <p>By enabling this setting without taking other precautions, you might expose your
* application to click-hijacking attacks. In these attacks, sanitized svg elements could be positioned
* outside of the containing element and be rendered over other elements on the page (e.g. a login
* link). Such behavior can then result in phishing incidents.</p>
*
* <p>To protect against these, explicitly setup `overflow: hidden` css rule for all potential svg
* tags within the sanitized content:</p>
*
* <br>
*
* <pre><code>
* .rootOfTheIncludedContent svg {
* overflow: hidden !important;
* }
* </code></pre>
* </div>
*
* @param {boolean=} flag Enable or disable SVG support in the sanitizer.
* @returns {boolean|$sanitizeProvider} Returns the currently configured value if called
* without an argument or self for chaining otherwise.
*/
this.enableSvg = function(enableSvg) {
if (isDefined(enableSvg)) {
svgEnabled = enableSvg;
return this;
} else {
return svgEnabled;
}
};
/**
* @ngdoc method
* @name $sanitizeProvider#addValidElements
* @kind function
*
* @description
* Extends the built-in lists of valid HTML/SVG elements, i.e. elements that are considered safe
* and are not stripped off during sanitization. You can extend the following lists of elements:
*
* - `htmlElements`: A list of elements (tag names) to extend the current list of safe HTML
* elements. HTML elements considered safe will not be removed during sanitization. All other
* elements will be stripped off.
*
* - `htmlVoidElements`: This is similar to `htmlElements`, but marks the elements as
* "void elements" (similar to HTML
* [void elements](https://rawgit.com/w3c/html/html5.1-2/single-page.html#void-elements)). These
* elements have no end tag and cannot have content.
*
* - `svgElements`: This is similar to `htmlElements`, but for SVG elements. This list is only
* taken into account if SVG is {@link ngSanitize.$sanitizeProvider#enableSvg enabled} for
* `$sanitize`.
*
* <div class="alert alert-info">
* This method must be called during the {@link angular.Module#config config} phase. Once the
* `$sanitize` service has been instantiated, this method has no effect.
* </div>
*
* <div class="alert alert-warning">
* Keep in mind that extending the built-in lists of elements may expose your app to XSS or
* other vulnerabilities. Be very mindful of the elements you add.
* </div>
*
* @param {Array<String>|Object} elements - A list of valid HTML elements or an object with one or
* more of the following properties:
* - **htmlElements** - `{Array<String>}` - A list of elements to extend the current list of
* HTML elements.
* - **htmlVoidElements** - `{Array<String>}` - A list of elements to extend the current list of
* void HTML elements; i.e. elements that do not have an end tag.
* - **svgElements** - `{Array<String>}` - A list of elements to extend the current list of SVG
* elements. The list of SVG elements is only taken into account if SVG is
* {@link ngSanitize.$sanitizeProvider#enableSvg enabled} for `$sanitize`.
*
* Passing an array (`[...]`) is equivalent to passing `{htmlElements: [...]}`.
*
* @return {$sanitizeProvider} Returns self for chaining.
*/
this.addValidElements = function(elements) {
if (!hasBeenInstantiated) {
if (isArray(elements)) {
elements = {htmlElements: elements};
}
addElementsTo(svgElements, elements.svgElements);
addElementsTo(voidElements, elements.htmlVoidElements);
addElementsTo(validElements, elements.htmlVoidElements);
addElementsTo(validElements, elements.htmlElements);
}
return this;
};
/**
* @ngdoc method
* @name $sanitizeProvider#addValidAttrs
* @kind function
*
* @description
* Extends the built-in list of valid attributes, i.e. attributes that are considered safe and are
* not stripped off during sanitization.
*
* **Note**:
* The new attributes will not be treated as URI attributes, which means their values will not be
* sanitized as URIs using `$compileProvider`'s
* {@link ng.$compileProvider#aHrefSanitizationTrustedUrlList aHrefSanitizationTrustedUrlList} and
* {@link ng.$compileProvider#imgSrcSanitizationTrustedUrlList imgSrcSanitizationTrustedUrlList}.
*
* <div class="alert alert-info">
* This method must be called during the {@link angular.Module#config config} phase. Once the
* `$sanitize` service has been instantiated, this method has no effect.
* </div>
*
* <div class="alert alert-warning">
* Keep in mind that extending the built-in list of attributes may expose your app to XSS or
* other vulnerabilities. Be very mindful of the attributes you add.
* </div>
*
* @param {Array<String>} attrs - A list of valid attributes.
*
* @returns {$sanitizeProvider} Returns self for chaining.
*/
this.addValidAttrs = function(attrs) {
if (!hasBeenInstantiated) {
extend(validAttrs, arrayToMap(attrs, true));
}
return this;
};
//////////////////////////////////////////////////////////////////////////////////////////////////
// Private stuff
//////////////////////////////////////////////////////////////////////////////////////////////////
bind = angular.bind;
extend = angular.extend;
forEach = angular.forEach;
isArray = angular.isArray;
isDefined = angular.isDefined;
lowercase = angular.$$lowercase;
noop = angular.noop;
htmlParser = htmlParserImpl;
htmlSanitizeWriter = htmlSanitizeWriterImpl;
nodeContains = window.Node.prototype.contains || /** @this */ function(arg) {
// eslint-disable-next-line no-bitwise
return !!(this.compareDocumentPosition(arg) & 16);
};
// Regular Expressions for parsing tags and attributes
var SURROGATE_PAIR_REGEXP = /[\uD800-\uDBFF][\uDC00-\uDFFF]/g,
// Match everything outside of normal chars and " (quote character)
NON_ALPHANUMERIC_REGEXP = /([^#-~ |!])/g;
// Good source of info about elements and attributes
// http://dev.w3.org/html5/spec/Overview.html#semantics
// http://simon.html5.org/html-elements
// Safe Void Elements - HTML5
// http://dev.w3.org/html5/spec/Overview.html#void-elements
var voidElements = stringToMap('area,br,col,hr,img,wbr');
// Elements that you can, intentionally, leave open (and which close themselves)
// http://dev.w3.org/html5/spec/Overview.html#optional-tags
var optionalEndTagBlockElements = stringToMap('colgroup,dd,dt,li,p,tbody,td,tfoot,th,thead,tr'),
optionalEndTagInlineElements = stringToMap('rp,rt'),
optionalEndTagElements = extend({},
optionalEndTagInlineElements,
optionalEndTagBlockElements);
// Safe Block Elements - HTML5
var blockElements = extend({}, optionalEndTagBlockElements, stringToMap('address,article,' +
'aside,blockquote,caption,center,del,dir,div,dl,figure,figcaption,footer,h1,h2,h3,h4,h5,' +
'h6,header,hgroup,hr,ins,map,menu,nav,ol,pre,section,table,ul'));
// Inline Elements - HTML5
var inlineElements = extend({}, optionalEndTagInlineElements, stringToMap('a,abbr,acronym,b,' +
'bdi,bdo,big,br,cite,code,del,dfn,em,font,i,img,ins,kbd,label,map,mark,q,ruby,rp,rt,s,' +
'samp,small,span,strike,strong,sub,sup,time,tt,u,var'));
// SVG Elements
// https://wiki.whatwg.org/wiki/Sanitization_rules#svg_Elements
// Note: the elements animate,animateColor,animateMotion,animateTransform,set are intentionally omitted.
// They can potentially allow for arbitrary javascript to be executed. See #11290
var svgElements = stringToMap('circle,defs,desc,ellipse,font-face,font-face-name,font-face-src,g,glyph,' +
'hkern,image,linearGradient,line,marker,metadata,missing-glyph,mpath,path,polygon,polyline,' +
'radialGradient,rect,stop,svg,switch,text,title,tspan');
// Blocked Elements (will be stripped)
var blockedElements = stringToMap('script,style');
var validElements = extend({},
voidElements,
blockElements,
inlineElements,
optionalEndTagElements);
//Attributes that have href and hence need to be sanitized
var uriAttrs = stringToMap('background,cite,href,longdesc,src,xlink:href,xml:base');
var htmlAttrs = stringToMap('abbr,align,alt,axis,bgcolor,border,cellpadding,cellspacing,class,clear,' +
'color,cols,colspan,compact,coords,dir,face,headers,height,hreflang,hspace,' +
'ismap,lang,language,nohref,nowrap,rel,rev,rows,rowspan,rules,' +
'scope,scrolling,shape,size,span,start,summary,tabindex,target,title,type,' +
'valign,value,vspace,width');
// SVG attributes (without "id" and "name" attributes)
// https://wiki.whatwg.org/wiki/Sanitization_rules#svg_Attributes
var svgAttrs = stringToMap('accent-height,accumulate,additive,alphabetic,arabic-form,ascent,' +
'baseProfile,bbox,begin,by,calcMode,cap-height,class,color,color-rendering,content,' +
'cx,cy,d,dx,dy,descent,display,dur,end,fill,fill-rule,font-family,font-size,font-stretch,' +
'font-style,font-variant,font-weight,from,fx,fy,g1,g2,glyph-name,gradientUnits,hanging,' +
'height,horiz-adv-x,horiz-origin-x,ideographic,k,keyPoints,keySplines,keyTimes,lang,' +
'marker-end,marker-mid,marker-start,markerHeight,markerUnits,markerWidth,mathematical,' +
'max,min,offset,opacity,orient,origin,overline-position,overline-thickness,panose-1,' +
'path,pathLength,points,preserveAspectRatio,r,refX,refY,repeatCount,repeatDur,' +
'requiredExtensions,requiredFeatures,restart,rotate,rx,ry,slope,stemh,stemv,stop-color,' +
'stop-opacity,strikethrough-position,strikethrough-thickness,stroke,stroke-dasharray,' +
'stroke-dashoffset,stroke-linecap,stroke-linejoin,stroke-miterlimit,stroke-opacity,' +
'stroke-width,systemLanguage,target,text-anchor,to,transform,type,u1,u2,underline-position,' +
'underline-thickness,unicode,unicode-range,units-per-em,values,version,viewBox,visibility,' +
'width,widths,x,x-height,x1,x2,xlink:actuate,xlink:arcrole,xlink:role,xlink:show,xlink:title,' +
'xlink:type,xml:base,xml:lang,xml:space,xmlns,xmlns:xlink,y,y1,y2,zoomAndPan', true);
var validAttrs = extend({},
uriAttrs,
svgAttrs,
htmlAttrs);
function stringToMap(str, lowercaseKeys) {
return arrayToMap(str.split(','), lowercaseKeys);
}
function arrayToMap(items, lowercaseKeys) {
var obj = {}, i;
for (i = 0; i < items.length; i++) {
obj[lowercaseKeys ? lowercase(items[i]) : items[i]] = true;
}
return obj;
}
function addElementsTo(elementsMap, newElements) {
if (newElements && newElements.length) {
extend(elementsMap, arrayToMap(newElements));
}
}
/**
* Create an inert document that contains the dirty HTML that needs sanitizing.
* We use the DOMParser API by default and fall back to createHTMLDocument if DOMParser is not
* available.
*/
var getInertBodyElement /* function(html: string): HTMLBodyElement */ = (function(window, document) {
if (isDOMParserAvailable()) {
return getInertBodyElement_DOMParser;
}
if (!document || !document.implementation) {
throw $sanitizeMinErr('noinert', 'Can\'t create an inert html document');
}
var inertDocument = document.implementation.createHTMLDocument('inert');
var inertBodyElement = (inertDocument.documentElement || inertDocument.getDocumentElement()).querySelector('body');
return getInertBodyElement_InertDocument;
function isDOMParserAvailable() {
try {
return !!getInertBodyElement_DOMParser('');
} catch (e) {
return false;
}
}
function getInertBodyElement_DOMParser(html) {
// We add this dummy element to ensure that the rest of the content is parsed as expected
// e.g. leading whitespace is maintained and tags like `<meta>` do not get hoisted to the `<head>` tag.
html = '<remove></remove>' + html;
try {
var body = new window.DOMParser().parseFromString(html, 'text/html').body;
body.firstChild.remove();
return body;
} catch (e) {
return undefined;
}
}
function getInertBodyElement_InertDocument(html) {
inertBodyElement.innerHTML = html;
// Support: IE 9-11 only
// strip custom-namespaced attributes on IE<=11
if (document.documentMode) {
stripCustomNsAttrs(inertBodyElement);
}
return inertBodyElement;
}
})(window, window.document);
/**
* @example
* htmlParser(htmlString, {
* start: function(tag, attrs) {},
* end: function(tag) {},
* chars: function(text) {},
* comment: function(text) {}
* });
*
* @param {string} html string
* @param {object} handler
*/
function htmlParserImpl(html, handler) {
if (html === null || html === undefined) {
html = '';
} else if (typeof html !== 'string') {
html = '' + html;
}
var inertBodyElement = getInertBodyElement(html);
if (!inertBodyElement) return '';
//mXSS protection
var mXSSAttempts = 5;
do {
if (mXSSAttempts === 0) {
throw $sanitizeMinErr('uinput', 'Failed to sanitize html because the input is unstable');
}
mXSSAttempts--;
// trigger mXSS if it is going to happen by reading and writing the innerHTML
html = inertBodyElement.innerHTML;
inertBodyElement = getInertBodyElement(html);
} while (html !== inertBodyElement.innerHTML);
var node = inertBodyElement.firstChild;
while (node) {
switch (node.nodeType) {
case 1: // ELEMENT_NODE
handler.start(node.nodeName.toLowerCase(), attrToMap(node.attributes));
break;
case 3: // TEXT NODE
handler.chars(node.textContent);
break;
}
var nextNode;
if (!(nextNode = node.firstChild)) {
if (node.nodeType === 1) {
handler.end(node.nodeName.toLowerCase());
}
nextNode = getNonDescendant('nextSibling', node);
if (!nextNode) {
while (nextNode == null) {
node = getNonDescendant('parentNode', node);
if (node === inertBodyElement) break;
nextNode = getNonDescendant('nextSibling', node);
if (node.nodeType === 1) {
handler.end(node.nodeName.toLowerCase());
}
}
}
}
node = nextNode;
}
while ((node = inertBodyElement.firstChild)) {
inertBodyElement.removeChild(node);
}
}
function attrToMap(attrs) {
var map = {};
for (var i = 0, ii = attrs.length; i < ii; i++) {
var attr = attrs[i];
map[attr.name] = attr.value;
}
return map;
}
/**
* Escapes all potentially dangerous characters, so that the
* resulting string can be safely inserted into attribute or
* element text.
* @param value
* @returns {string} escaped text
*/
function encodeEntities(value) {
return value.
replace(/&/g, '&').
replace(SURROGATE_PAIR_REGEXP, function(value) {
var hi = value.charCodeAt(0);
var low = value.charCodeAt(1);
return '&#' + (((hi - 0xD800) * 0x400) + (low - 0xDC00) + 0x10000) + ';';
}).
replace(NON_ALPHANUMERIC_REGEXP, function(value) {
return '&#' + value.charCodeAt(0) + ';';
}).
replace(/</g, '<').
replace(/>/g, '>');
}
/**
* create an HTML/XML writer which writes to buffer
* @param {Array} buf use buf.join('') to get out sanitized html string
* @returns {object} in the form of {
* start: function(tag, attrs) {},
* end: function(tag) {},
* chars: function(text) {},
* comment: function(text) {}
* }
*/
function htmlSanitizeWriterImpl(buf, uriValidator) {
var ignoreCurrentElement = false;
var out = bind(buf, buf.push);
return {
start: function(tag, attrs) {
tag = lowercase(tag);
if (!ignoreCurrentElement && blockedElements[tag]) {
ignoreCurrentElement = tag;
}
if (!ignoreCurrentElement && validElements[tag] === true) {
out('<');
out(tag);
forEach(attrs, function(value, key) {
var lkey = lowercase(key);
var isImage = (tag === 'img' && lkey === 'src') || (lkey === 'background');
if (validAttrs[lkey] === true &&
(uriAttrs[lkey] !== true || uriValidator(value, isImage))) {
out(' ');
out(key);
out('="');
out(encodeEntities(value));
out('"');
}
});
out('>');
}
},
end: function(tag) {
tag = lowercase(tag);
if (!ignoreCurrentElement && validElements[tag] === true && voidElements[tag] !== true) {
out('</');
out(tag);
out('>');
}
// eslint-disable-next-line eqeqeq
if (tag == ignoreCurrentElement) {
ignoreCurrentElement = false;
}
},
chars: function(chars) {
if (!ignoreCurrentElement) {
out(encodeEntities(chars));
}
}
};
}
/**
* When IE9-11 comes across an unknown namespaced attribute e.g. 'xlink:foo' it adds 'xmlns:ns1' attribute to declare
* ns1 namespace and prefixes the attribute with 'ns1' (e.g. 'ns1:xlink:foo'). This is undesirable since we don't want
* to allow any of these custom attributes. This method strips them all.
*
* @param node Root element to process
*/
function stripCustomNsAttrs(node) {
while (node) {
if (node.nodeType === window.Node.ELEMENT_NODE) {
var attrs = node.attributes;
for (var i = 0, l = attrs.length; i < l; i++) {
var attrNode = attrs[i];
var attrName = attrNode.name.toLowerCase();
if (attrName === 'xmlns:ns1' || attrName.lastIndexOf('ns1:', 0) === 0) {
node.removeAttributeNode(attrNode);
i--;
l--;
}
}
}
var nextNode = node.firstChild;
if (nextNode) {
stripCustomNsAttrs(nextNode);
}
node = getNonDescendant('nextSibling', node);
}
}
function getNonDescendant(propName, node) {
// An element is clobbered if its `propName` property points to one of its descendants
var nextNode = node[propName];
if (nextNode && nodeContains.call(node, nextNode)) {
throw $sanitizeMinErr('elclob', 'Failed to sanitize html because the element is clobbered: {0}', node.outerHTML || node.outerText);
}
return nextNode;
}
}
function sanitizeText(chars) {
var buf = [];
var writer = htmlSanitizeWriter(buf, noop);
writer.chars(chars);
return buf.join('');
}
// define ngSanitize module and register $sanitize service
angular.module('ngSanitize', [])
.provider('$sanitize', $SanitizeProvider)
.info({ angularVersion: '"NG_VERSION_FULL"' });