/* | |
* Copyright (C) 2009 Google Inc. All rights reserved. | |
* | |
* Redistribution and use in source and binary forms, with or without | |
* modification, are permitted provided that the following conditions are | |
* met: | |
* | |
* * Redistributions of source code must retain the above copyright | |
* notice, this list of conditions and the following disclaimer. | |
* * 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. | |
* * Neither the name of Google Inc. nor the names of its | |
* contributors may be used to endorse or promote products derived from | |
* this software without specific prior written permission. | |
* | |
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
* "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 THE COPYRIGHT | |
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
*/ | |
#include "config.h" | |
#include "BindingSecurityBase.h" | |
#include "DOMWindow.h" | |
#include "Frame.h" | |
#include "SecurityOrigin.h" | |
namespace WebCore { | |
DOMWindow* BindingSecurityBase::getDOMWindow(Frame* frame) | |
{ | |
return frame->domWindow(); | |
} | |
Frame* BindingSecurityBase::getFrame(Node* node) | |
{ | |
return node->document()->frame(); | |
} | |
// Same origin policy implementation: | |
// | |
// Same origin policy prevents JS code from domain A from accessing JS & DOM | |
// objects in a different domain B. There are exceptions and several objects | |
// are accessible by cross-domain code. For example, the window.frames object | |
// is accessible by code from a different domain, but window.document is not. | |
// | |
// The JS binding code sets security check callbacks on a function template, | |
// and accessing instances of the template calls the callback function. | |
// The callback function enforces the same origin policy. | |
// | |
// Callback functions are expensive. Binding code should use a security token | |
// string to do fast access checks for the common case where source and target | |
// are in the same domain. A security token is a string object that represents | |
// the protocol/url/port of a domain. | |
// | |
// There are special cases where security token matching is not enough. | |
// For example, JS can set its domain to a super domain by calling | |
// document.setDomain(...). In these cases, the binding code can reset | |
// a context's security token to its global object so that the fast access | |
// check will always fail. | |
// Helper to check if the current execution context can access a target frame. | |
// First it checks same domain policy using the lexical context. | |
// | |
// This is equivalent to KJS::Window::allowsAccessFrom(ExecState*). | |
bool BindingSecurityBase::canAccess(DOMWindow* activeWindow, | |
DOMWindow* targetWindow) | |
{ | |
ASSERT(targetWindow); | |
String message; | |
if (activeWindow == targetWindow) | |
return true; | |
if (!activeWindow) | |
return false; | |
const SecurityOrigin* activeSecurityOrigin = activeWindow->securityOrigin(); | |
const SecurityOrigin* targetSecurityOrigin = targetWindow->securityOrigin(); | |
// We have seen crashes were the security origin of the target has not been | |
// initialized. Defend against that. | |
if (!targetSecurityOrigin) | |
return false; | |
if (activeSecurityOrigin->canAccess(targetSecurityOrigin)) | |
return true; | |
// Allow access to a "about:blank" page if the dynamic context is a | |
// detached context of the same frame as the blank page. | |
if (targetSecurityOrigin->isEmpty() && activeWindow->frame() == targetWindow->frame()) | |
return true; | |
return false; | |
} | |
} // namespace WebCore |