Source code
Revision control
Copy as Markdown
Other Tools
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#ifndef _xpc_WRAPPERFACTORY_H
#define _xpc_WRAPPERFACTORY_H
#include "js/Wrapper.h"
namespace xpc {
/**
* A wrapper that's only used for cross-origin objects. This should be
* just like a CrossCompartmentWrapper but (as an implementation
* detail) doesn't actually do any compartment-entering and (as an
* implementation detail) delegates all the security decisions and
* compartment-entering to the target object, which is always a
* proxy.
*
* We could also inherit from CrossCompartmentWrapper but then we
* would need to override all the proxy hooks to avoid the
* compartment-entering bits.
*/
class CrossOriginObjectWrapper : public js::Wrapper {
public:
// We want to claim to have a security policy, so code doesn't just
// CheckedUnwrap us willy-nilly. But we're OK with the BaseProxyHandler
// implementation of enter(), which allows entering. Our target is what
// really does the security checks.
//
// We don't want to inherit from CrossCompartmentWrapper, because we don't
// want the compartment-entering behavior it has. But we do want to set the
// CROSS_COMPARTMENT flag on js::Wrapper so that we test true for
// is<js::CrossCompartmentWrapperObject> and so forth.
constexpr explicit CrossOriginObjectWrapper()
: js::Wrapper(CROSS_COMPARTMENT, /* aHasPrototype = */ false,
/* aHasSecurityPolicy = */ true) {}
bool dynamicCheckedUnwrapAllowed(JS::Handle<JSObject*> obj,
JSContext* cx) const override;
// Cross origin objects should not participate in private fields.
virtual bool throwOnPrivateField() const override { return true; }
static const CrossOriginObjectWrapper singleton;
};
class WrapperFactory {
public:
enum {
WAIVE_XRAY_WRAPPER_FLAG = js::Wrapper::LAST_USED_FLAG << 1,
IS_XRAY_WRAPPER_FLAG = WAIVE_XRAY_WRAPPER_FLAG << 1
};
// Return true if any of any of the nested wrappers have the flag set.
static bool HasWrapperFlag(JSObject* wrapper, unsigned flag) {
unsigned flags = 0;
js::UncheckedUnwrap(wrapper, true, &flags);
return !!(flags & flag);
}
static bool IsXrayWrapper(JSObject* wrapper) {
return HasWrapperFlag(wrapper, IS_XRAY_WRAPPER_FLAG);
}
static bool IsCrossOriginWrapper(JSObject* obj) {
return (js::IsProxy(obj) &&
js::GetProxyHandler(obj) == &CrossOriginObjectWrapper::singleton);
}
static bool IsOpaqueWrapper(JSObject* obj);
static bool HasWaiveXrayFlag(JSObject* wrapper) {
return HasWrapperFlag(wrapper, WAIVE_XRAY_WRAPPER_FLAG);
}
static bool IsCOW(JSObject* wrapper);
static JSObject* GetXrayWaiver(JS::Handle<JSObject*> obj);
// If allowExisting is true, there is an existing waiver for obj in
// its scope, but we want to replace it with the new one.
static JSObject* CreateXrayWaiver(JSContext* cx, JS::Handle<JSObject*> obj,
bool allowExisting = false);
static JSObject* WaiveXray(JSContext* cx, JSObject* obj);
// Computes whether we should allow the creation of an Xray waiver from
// |target| to |origin|.
static bool AllowWaiver(JS::Compartment* target, JS::Compartment* origin);
// Convenience method for the above, operating on a wrapper.
static bool AllowWaiver(JSObject* wrapper);
// Prepare a given object for wrapping in a new compartment.
static void PrepareForWrapping(JSContext* cx, JS::Handle<JSObject*> scope,
JS::Handle<JSObject*> origObj,
JS::Handle<JSObject*> obj,
JS::Handle<JSObject*> objectPassedToWrap,
JS::MutableHandle<JSObject*> retObj);
// Rewrap an object that is about to cross compartment boundaries.
static JSObject* Rewrap(JSContext* cx, JS::Handle<JSObject*> existing,
JS::Handle<JSObject*> obj);
// Wrap wrapped object into a waiver wrapper and then re-wrap it.
static bool WaiveXrayAndWrap(JSContext* cx, JS::MutableHandle<JS::Value> vp);
static bool WaiveXrayAndWrap(JSContext* cx,
JS::MutableHandle<JSObject*> object);
};
} // namespace xpc
#endif /* _xpc_WRAPPERFACTORY_H */