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/*
* 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,
* 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.
*/
#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
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