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// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// @dart = 2.9
/// This tests HTML validation and sanitization, which is very important
/// for prevent XSS or other attacks. If you suppress this, or parts of it
/// please make it a critical bug and bring it to the attention of the
/// dart:html maintainers.
library node_validator_test;
import 'dart:html';
import 'dart:svg' as svg;
import 'package:expect/minitest.dart';
import 'utils.dart';
void validateHtml(String html, String reference, NodeValidator validator) {
var a = document.body.createFragment(html, validator: validator);
var b = document.body
.createFragment(reference, treeSanitizer: NodeTreeSanitizer.trusted);
// Prevent a false pass when both the html and the reference both get entirely
// deleted, which is technically a match, but unlikely to be what we meant.
if (reference != '') {
expect(b.childNodes.length > 0, isTrue);
}
validateNodeTree(a, b);
}
class RecordingUriValidator implements UriPolicy {
final List<String> calls = <String>[];
bool allowsUri(String uri) {
calls.add('$uri');
return false;
}
void reset() {
calls.clear();
}
}
void testHtml(String name, NodeValidator validator, String html,
[String reference]) {
test(name, () {
if (reference == null) {
reference = html;
}
validateHtml(html, reference, validator);
});
}
main() {
group('DOM_sanitization', () {
var validator = new NodeValidatorBuilder.common();
testHtml('allows simple constructs', validator,
'<div class="baz">something</div>');
testHtml('blocks unknown attributes', validator,
'<div foo="baz">something</div>', '<div>something</div>');
testHtml('blocks custom element', validator,
'<x-my-element>something</x-my-element>', '');
testHtml('blocks custom is element', validator,
'<div is="x-my-element">something</div>', '');
testHtml(
'blocks body elements', validator, '<body background="s"></body>', '');
testHtml(
'allows select elements',
validator,
'<select>'
'<option>a</option>'
'</select>');
testHtml('blocks sequential script elements', validator,
'<div><script></script><script></script></div>', '<div></div>');
testHtml('blocks inline styles', validator,
'<div style="background: red"></div>', '<div></div>');
testHtml('blocks namespaced attributes', validator,
'<div ns:foo="foo"></div>', '<div></div>');
testHtml('blocks namespaced common attributes', validator,
'<div ns:class="foo"></div>', '<div></div>');
testHtml('blocks namespaced common elements', validator,
'<ns:div></ns:div>', '');
testHtml('allows CDATA sections', validator,
'<span>![CDATA[ some text ]]></span>');
testHtml('backquotes not removed', validator,
'<img src="dice.png" alt="``onload=xss()" />');
testHtml('0x3000 not removed', validator,
'<a href="&#x3000;javascript:alert(1)">CLICKME</a>');
test('sanitizes template contents', () {
if (!TemplateElement.supported) return;
var html = '<template>'
'<div></div>'
'<script></script>'
'<img src="http://example.com/foo"/>'
'</template>';
var fragment = document.body.createFragment(html, validator: validator);
var template = fragment.nodes.single as TemplateElement;
var expectedContent = document.body.createFragment('<div></div>'
'<img/>');
validateNodeTree(template.content, expectedContent);
});
test("appendHtml is sanitized", () {
var html = '<body background="s"></body><div></div>';
document.body.appendHtml('<div id="stuff"></div>');
var stuff = document.querySelector("#stuff");
stuff.appendHtml(html);
expect(stuff.childNodes.length, 1);
stuff.remove();
});
test("documentFragment.appendHtml is sanitized", () {
var html = '<div id="things></div>';
var fragment = new DocumentFragment.html(html);
fragment.appendHtml('<div id="bad"><script></script></div>');
expect(fragment.childNodes.length, 1);
var child = fragment.childNodes[0] as Element;
expect(child.id, "bad");
expect(child.childNodes.length, 0);
});
testHtml(
"sanitizes embed",
validator,
"<div><embed src='' type='application/x-shockwave-flash'></embed></div>",
"<div></div>");
});
group('URI_sanitization', () {
var recorder = new RecordingUriValidator();
var validator = new NodeValidatorBuilder()..allowHtml5(uriPolicy: recorder);
checkUriPolicyCalls(String name, String html, String reference,
List<String> expectedCalls) {
test(name, () {
recorder.reset();
validateHtml(html, reference, validator);
expect(recorder.calls, expectedCalls);
});
}
checkUriPolicyCalls('a::href', '<a href="s"></a>', '<a></a>', ['s']);
checkUriPolicyCalls(
'area::href', '<area href="s"></area>', '<area></area>', ['s']);
checkUriPolicyCalls(
'blockquote::cite',
'<blockquote cite="s"></blockquote>',
'<blockquote></blockquote>',
['s']);
checkUriPolicyCalls(
'command::icon', '<command icon="s"/>', '<command/>', ['s']);
checkUriPolicyCalls('img::src', '<img src="s"/>', '<img/>', ['s']);
checkUriPolicyCalls('input::src', '<input src="s"/>', '<input/>', ['s']);
checkUriPolicyCalls(
'ins::cite', '<ins cite="s"></ins>', '<ins></ins>', ['s']);
checkUriPolicyCalls('q::cite', '<q cite="s"></q>', '<q></q>', ['s']);
checkUriPolicyCalls(
'video::poster', '<video poster="s"/>', '<video/>', ['s']);
});
group('allowNavigation', () {
var validator = new NodeValidatorBuilder()..allowNavigation();
testHtml('allows anchor tags', validator, '<a href="#foo">foo</a>');
testHtml('allows form elements', validator,
'<form method="post" action="/foo"></form>');
testHtml('disallows script navigation', validator,
'<a href="javascript:foo = 1">foo</a>', '<a>foo</a>');
testHtml('disallows cross-site navigation', validator,
'<a href="http://example.com">example.com</a>', '<a>example.com</a>');
testHtml('blocks other elements', validator,
'<a href="#foo"><b>foo</b></a>', '<a href="#foo"></a>');
testHtml('blocks tag extension', validator, '<a is="x-foo"></a>', '');
});
group('allowImages', () {
var validator = new NodeValidatorBuilder()..allowImages();
testHtml('allows images', validator,
'<img src="/foo.jpg" alt="something" width="100" height="100"/>');
testHtml('blocks onerror', validator,
'<img src="/foo.jpg" onerror="something"/>', '<img src="/foo.jpg"/>');
testHtml('enforces same-origin', validator,
'<img src="http://example.com/foo.jpg"/>', '<img/>');
});
group('allowCustomElement', () {
var validator = new NodeValidatorBuilder()
..allowCustomElement('x-foo', attributes: ['bar'], uriAttributes: ['baz'])
..allowHtml5();
testHtml('allows custom elements', validator,
'<x-foo bar="something" baz="/foo.jpg"></x-foo>');
testHtml('validates custom tag URIs', validator,
'<x-foo baz="http://example.com/foo.jpg"></x-foo>', '<x-foo></x-foo>');
testHtml('blocks type extensions', validator, '<div is="x-foo"></div>', '');
testHtml('blocks tags on non-matching elements', validator,
'<div bar="foo"></div>', '<div></div>');
});
group('identify Uri attributes listed as attributes', () {
var validator = new NodeValidatorBuilder()
..allowElement('a', attributes: ['href']);
testHtml(
'reject different-origin link',
validator,
'<a href="http://www.google.com/foo">Google-Foo</a>',
'<a>Google-Foo</a>');
});
group('allowTagExtension', () {
var validator = new NodeValidatorBuilder()
..allowTagExtension('x-foo', 'div',
attributes: ['bar'], uriAttributes: ['baz'])
..allowHtml5();
testHtml('allows tag extensions', validator,
'<div is="x-foo" bar="something" baz="/foo.jpg"></div>');
testHtml('blocks custom elements', validator, '<x-foo></x-foo>', '');
testHtml(
'validates tag extension URIs',
validator,
'<div is="x-foo" baz="http://example.com/foo.jpg"></div>',
'<div is="x-foo"></div>');
testHtml('blocks tags on non-matching elements', validator,
'<div bar="foo"></div>', '<div></div>');
testHtml('blocks non-matching tags', validator,
'<span is="x-foo">something</span>', '');
validator = new NodeValidatorBuilder()
..allowTagExtension('x-foo', 'div',
attributes: ['bar'], uriAttributes: ['baz'])
..allowTagExtension('x-else', 'div');
testHtml('blocks tags on non-matching custom elements', validator,
'<div bar="foo" is="x-else"></div>', '<div is="x-else"></div>');
});
group('allowTemplating', () {
var validator = new NodeValidatorBuilder()
..allowTemplating()
..allowHtml5();
testHtml(
'allows templates', validator, '<template bind="{{a}}"></template>');
testHtml('allows template attributes', validator,
'<template bind="{{a}}" ref="foo" repeat="{{}}" if="{{}}" syntax="foo"></template>');
testHtml('allows template attribute', validator,
'<div template repeat="{{}}"></div>');
testHtml('blocks illegal template attribute', validator,
'<div template="foo" repeat="{{}}"></div>', '<div></div>');
});
group('allowSvg', () {
var validator = new NodeValidatorBuilder()
..allowSvg()
..allowTextElements();
testHtml(
'allows basic SVG',
validator,
'<svg xmlns="http://www.w3.org/2000/svg'
'xmlns:xlink="http://www.w3.org/1999/xlink">'
'<image xlink:href="foo" data-foo="bar"/>'
'</svg>');
testHtml(
'blocks script elements',
validator,
'<svg xmlns="http://www.w3.org/2000/svg>'
'<script></script>'
'</svg>',
'');
testHtml(
'blocks script elements but allows other',
validator,
'<svg xmlns="http://www.w3.org/2000/svg>'
'<script></script><ellipse cx="200" cy="80" rx="100" ry="50"></ellipse>'
'</svg>',
'<svg xmlns="http://www.w3.org/2000/svg>'
'<ellipse cx="200" cy="80" rx="100" ry="50"></ellipse>'
'</svg>');
testHtml(
'blocks script handlers',
validator,
'<svg xmlns="http://www.w3.org/2000/svg'
'xmlns:xlink="http://www.w3.org/1999/xlink">'
'<image xlink:href="foo" onerror="something"/>'
'</svg>',
'<svg xmlns="http://www.w3.org/2000/svg'
'xmlns:xlink="http://www.w3.org/1999/xlink">'
'<image xlink:href="foo"/>'
'</svg>');
testHtml(
'blocks foreignObject content',
validator,
'<svg xmlns="http://www.w3.org/2000/svg">'
'<foreignobject width="100" height="150">'
'<body xmlns="http://www.w3.org/1999/xhtml">'
'<div>Some content</div>'
'</body>'
'</foreignobject>'
'<b>42</b>'
'</svg>',
'<svg xmlns="http://www.w3.org/2000/svg">'
'<b>42</b>'
'</svg>');
});
group('allowInlineStyles', () {
var validator = new NodeValidatorBuilder()
..allowTextElements()
..allowInlineStyles();
testHtml('allows inline styles', validator,
'<span style="background-color:red">text</span>');
testHtml('blocks other attributes', validator,
'<span class="red-span"></span>', '<span></span>');
validator = new NodeValidatorBuilder()
..allowTextElements()
..allowInlineStyles(tagName: 'span');
testHtml('scoped allows inline styles on spans', validator,
'<span style="background-color:red">text</span>');
testHtml('scoped blocks inline styles on LIs', validator,
'<li style="background-color:red">text</li>', '<li>text</li>');
});
group('throws', () {
var validator = new NodeValidator.throws(new NodeValidatorBuilder.common());
var validationError = throwsArgumentError;
test('does not throw on valid syntax', () {
expect(() {
document.body.createFragment('<div></div>', validator: validator);
}, returnsNormally);
});
test('throws on invalid elements', () {
expect(() {
document.body.createFragment('<foo></foo>', validator: validator);
}, validationError);
});
test('throws on invalid attributes', () {
expect(() {
document.body
.createFragment('<div foo="bar"></div>', validator: validator);
}, validationError);
});
test('throws on invalid attribute values', () {
expect(() {
document.body.createFragment('<img src="http://example.com/foo.jpg"/>',
validator: validator);
}, validationError);
});
});
group('svg', () {
test('parsing', () {
var svgText = '<svg xmlns="http://www.w3.org/2000/svg'
'xmlns:xlink="http://www.w3.org/1999/xlink">'
'<image xlink:href="foo" data-foo="bar"/>'
'</svg>';
var fragment = new DocumentFragment.svg(svgText);
var element = fragment.nodes.first as Element;
expect(element is svg.SvgSvgElement, isTrue);
expect(element.children[0] is svg.ImageElement, isTrue);
});
});
group('dom_clobbering', () {
var validator = new NodeValidatorBuilder.common();
testHtml(
'DOM clobbering of attributes with single node',
validator,
"<form id='single_node_clobbering' onmouseover='alert(1)'><input name='attributes'>",
"");
testHtml('DOM clobbering of previousSibling',
validator,
'https://example.com/<div><img/src="x"/onerror="alert();"/><form><input/name="previousSibling"></form></div>',
'https://example.com/<div><img src="x"></div>'
);
// The lastChild and childNodes clobbering corrupts iterating the tree. They
// get removed, but in the meantime the evil node has been skipped. Note
// that we end up deleting the entire form because the clobbering makes its
// lastChild incorrect and we detect this, but only on the second time
// through.
testHtml('DOM clobbering of both childNodes and lastChild',
validator,
"abc<form><div><img src='x' onerror='alert(document.domain)'></div><div><input name='childNodes'><input id='lastChild' name='childNodes'></div></form>",
'abc'
);
test('DOM clobbering of previousSibling via append', () {
var div = Element.div();
var bad =
'https://example.com/<div><img/src="x"/onerror="alert();"/><form><input/name="previousSibling"></form></div>';
div.innerHtml = bad;
expect(div.innerHtml, 'https://example.com/<div><img src="x"></div>');
});
testHtml(
'DOM clobbering of attributes with multiple nodes',
validator,
"<form onmouseover='alert(1)'><input name='attributes'>"
"<input name='attributes'>",
"");
testHtml('DOM clobbering of lastChild', validator,
"<form><input name='lastChild'><input onmouseover='alert(1)'>", "");
testHtml(
'DOM clobbering of both children and lastChild',
validator,
"<form><input name='lastChild'><input name='children'>"
"<input id='children'><input onmouseover='alert(1)'>",
"");
testHtml(
'DOM clobbering of both children and lastChild, different order',
validator,
"<form><input name='children'><input name='children'>"
"<input id='children' name='lastChild'>"
"<input id='bad' onmouseover='alert(1)'>",
"");
// Walking templates triggers a recursive sanitization call, which shouldn't
// invalidate the information collected from the previous visit of the later
// nodes in the walk.
testHtml(
'DOM clobbering with recursive sanitize call using templates',
validator,
"<form><div>"
"<input id=childNodes />"
"<template></template>"
"<input id=childNodes name=lastChild />"
"<img id=exploitImg src=0 onerror='alert(1)' />"
"</div></form>",
"");
test('tagName makes containing form invalid', () {
var fragment = document.body.createFragment(
"<form onmouseover='alert(2)'><input name='tagName'>",
validator: validator);
var form = fragment.lastChild as FormElement;
// If the tagName was clobbered, the sanitizer should have removed
// the whole thing and form is null.
// If the tagName was not clobbered, then there will be content,
// but the tagName should be the normal value. IE11 has started
// doing this.
if (form != null) {
expect(form.tagName, 'FORM');
}
});
test('tagName without mouseover', () {
var fragment = document.body
.createFragment("<form><input name='tagName'>", validator: validator);
var form = fragment.lastChild as FormElement;
// If the tagName was clobbered, the sanitizer should have removed
// the whole thing and form is null.
// If the tagName was not clobbered, then there will be content,
// but the tagName should be the normal value.
if (form != null) {
expect(form.tagName, 'FORM');
}
});
});
}