diff -r 000000000000 -r 4f2f89ce4247 WebCore/bindings/generic/BindingSecurityBase.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/bindings/generic/BindingSecurityBase.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,108 @@
+/*
+ * 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