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/*
* Copyright (C) 2008, 2009 Daniel Bates (dbates@intudata.com)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef XSSAuditor_h
#define XSSAuditor_h
#include "HTTPParsers.h"
#include "PlatformString.h"
#include "SuffixTree.h"
#include "TextEncoding.h"
namespace WebCore {
class FormData;
class Frame;
class ScriptSourceCode;
// The XSSAuditor class is used to prevent type 1 cross-site scripting
// vulnerabilities (also known as reflected vulnerabilities).
//
// More specifically, the XSSAuditor class decides whether the execution of
// a script is to be allowed or denied based on the content of any
// user-submitted data, including:
//
// * the URL.
// * the HTTP-POST data.
//
// If the source code of a script resembles any user-submitted data then it
// is denied execution.
//
// When you instantiate the XSSAuditor you must specify the Frame of the
// page that you wish to audit.
//
// Bindings
//
// An XSSAuditor is instantiated within the constructor of a
// ScriptController object and passed the Frame the script originated. The
// ScriptController calls back to the XSSAuditor to determine whether a
// JavaScript script is safe to execute before executing it. The following
// methods call into XSSAuditor:
//
// * ScriptController::evaluateInWorld - used to evaluate JavaScript scripts.
// * ScriptController::executeIfJavaScriptURL - used to evaluate JavaScript URLs.
// * ScriptEventListener::createAttributeEventListener - used to create JavaScript event handlers.
// * HTMLBaseElement::process - used to set the document base URL.
// * LegacyHTMLDocumentParser::parseTag - used to load external JavaScript scripts.
// * SubframeLoader::requestObject - used to load <object>/<embed> elements.
//
class XSSAuditor : public Noncopyable {
public:
XSSAuditor(Frame*);
~XSSAuditor();
bool isEnabled() const;
// Determines whether the script should be allowed or denied execution
// based on the content of any user-submitted data.
bool canEvaluate(const String& code) const;
// Determines whether the JavaScript URL should be allowed or denied execution
// based on the content of any user-submitted data.
bool canEvaluateJavaScriptURL(const String& code) const;
// Determines whether the event listener should be created based on the
// content of any user-submitted data.
bool canCreateInlineEventListener(const String& functionName, const String& code) const;
// Determines whether the external script should be loaded based on the
// content of any user-submitted data.
bool canLoadExternalScriptFromSrc(const String& url) const;
// Determines whether object should be loaded based on the content of
// any user-submitted data.
//
// This method is called by SubframeLoader::requestObject.
bool canLoadObject(const String& url) const;
// Determines whether the base URL should be changed based on the content
// of any user-submitted data.
//
// This method is called by HTMLBaseElement::process.
bool canSetBaseElementURL(const String& url) const;
private:
class CachingURLCanonicalizer
{
public:
CachingURLCanonicalizer() : m_decodeEntities(false), m_decodeURLEscapeSequencesTwice(false), m_generation(0) { }
String canonicalizeURL(FormData*, const TextEncoding& encoding, bool decodeEntities,
bool decodeURLEscapeSequencesTwice);
String canonicalizeURL(const String& url, const TextEncoding& encoding, bool decodeEntities,
bool decodeURLEscapeSequencesTwice);
void clear();
int generation() const { return m_generation; }
private:
// The parameters we were called with last.
String m_inputURL;
TextEncoding m_encoding;
bool m_decodeEntities;
bool m_decodeURLEscapeSequencesTwice;
RefPtr<FormData> m_formData;
// Incremented every time we see a new URL.
int m_generation;
// The cached result.
String m_cachedCanonicalizedURL;
};
struct FindTask {
FindTask()
: decodeEntities(true)
, allowRequestIfNoIllegalURICharacters(false)
, decodeURLEscapeSequencesTwice(false)
{
}
String context;
String string;
bool decodeEntities;
bool allowRequestIfNoIllegalURICharacters;
bool decodeURLEscapeSequencesTwice;
};
static String canonicalize(const String&);
static String decodeURL(const String& url, const TextEncoding& encoding, bool decodeEntities,
bool decodeURLEscapeSequencesTwice = false);
static String decodeHTMLEntities(const String&, bool leaveUndecodableEntitiesUntouched = true);
bool isSameOriginResource(const String& url) const;
bool findInRequest(const FindTask&) const;
bool findInRequest(Frame*, const FindTask&) const;
XSSProtectionDisposition xssProtection() const;
// The frame to audit.
Frame* m_frame;
// A state store to help us avoid canonicalizing the same URL repeated.
// When a page has form data, we need two caches: one to store the
// canonicalized URL and another to store the cannonicalized form
// data. If we only had one cache, we'd always generate a cache miss
// and load some pages extremely slowly.
// https://bugs.webkit.org/show_bug.cgi?id=35373
mutable CachingURLCanonicalizer m_pageURLCache;
mutable CachingURLCanonicalizer m_formDataCache;
mutable OwnPtr<SuffixTree<ASCIICodebook> > m_formDataSuffixTree;
mutable int m_generationOfSuffixTree;
};
} // namespace WebCore
#endif // XSSAuditor_h
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