gecko-dev/js/public/Wrapper.h
Boris Zbarsky 1fa4aa00d2 Bug 1521907 part 1. Add a version of CheckedUnwrap that can do a dynamic security check. r=jandem,sfink
We're going to need this because we will have multiple Realms in the same
compartment which want different CheckedUnwrap behavior in some cases.  So we
need to be able to check which Realm we're in.

Differential Revision: https://phabricator.services.mozilla.com/D17881

--HG--
extra : moz-landing-system : lando
2019-02-02 03:22:29 +00:00

492 lines
24 KiB
C++

/* -*- 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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef js_Wrapper_h
#define js_Wrapper_h
#include "mozilla/Attributes.h"
#include "js/Proxy.h"
namespace js {
/*
* Helper for Wrapper::New default options.
*
* Callers of Wrapper::New() who wish to specify a prototype for the created
* Wrapper, *MUST* construct a WrapperOptions with a JSContext.
*/
class MOZ_STACK_CLASS WrapperOptions : public ProxyOptions {
public:
WrapperOptions() : ProxyOptions(false), proto_() {}
explicit WrapperOptions(JSContext* cx) : ProxyOptions(false), proto_() {
proto_.emplace(cx);
}
inline JSObject* proto() const;
WrapperOptions& setProto(JSObject* protoArg) {
MOZ_ASSERT(proto_);
*proto_ = protoArg;
return *this;
}
private:
mozilla::Maybe<JS::RootedObject> proto_;
};
// Base class for proxy handlers that want to forward all operations to an
// object stored in the proxy's private slot.
class JS_FRIEND_API ForwardingProxyHandler : public BaseProxyHandler {
public:
using BaseProxyHandler::BaseProxyHandler;
/* Standard internal methods. */
virtual bool getOwnPropertyDescriptor(
JSContext* cx, HandleObject proxy, HandleId id,
MutableHandle<PropertyDescriptor> desc) const override;
virtual bool defineProperty(JSContext* cx, HandleObject proxy, HandleId id,
Handle<PropertyDescriptor> desc,
ObjectOpResult& result) const override;
virtual bool ownPropertyKeys(JSContext* cx, HandleObject proxy,
AutoIdVector& props) const override;
virtual bool delete_(JSContext* cx, HandleObject proxy, HandleId id,
ObjectOpResult& result) const override;
virtual JSObject* enumerate(JSContext* cx, HandleObject proxy) const override;
virtual bool getPrototype(JSContext* cx, HandleObject proxy,
MutableHandleObject protop) const override;
virtual bool setPrototype(JSContext* cx, HandleObject proxy,
HandleObject proto,
ObjectOpResult& result) const override;
virtual bool getPrototypeIfOrdinary(
JSContext* cx, HandleObject proxy, bool* isOrdinary,
MutableHandleObject protop) const override;
virtual bool setImmutablePrototype(JSContext* cx, HandleObject proxy,
bool* succeeded) const override;
virtual bool preventExtensions(JSContext* cx, HandleObject proxy,
ObjectOpResult& result) const override;
virtual bool isExtensible(JSContext* cx, HandleObject proxy,
bool* extensible) const override;
virtual bool has(JSContext* cx, HandleObject proxy, HandleId id,
bool* bp) const override;
virtual bool get(JSContext* cx, HandleObject proxy, HandleValue receiver,
HandleId id, MutableHandleValue vp) const override;
virtual bool set(JSContext* cx, HandleObject proxy, HandleId id,
HandleValue v, HandleValue receiver,
ObjectOpResult& result) const override;
virtual bool call(JSContext* cx, HandleObject proxy,
const CallArgs& args) const override;
virtual bool construct(JSContext* cx, HandleObject proxy,
const CallArgs& args) const override;
/* SpiderMonkey extensions. */
virtual bool hasOwn(JSContext* cx, HandleObject proxy, HandleId id,
bool* bp) const override;
virtual bool getOwnEnumerablePropertyKeys(JSContext* cx, HandleObject proxy,
AutoIdVector& props) const override;
virtual bool nativeCall(JSContext* cx, IsAcceptableThis test, NativeImpl impl,
const CallArgs& args) const override;
virtual bool hasInstance(JSContext* cx, HandleObject proxy,
MutableHandleValue v, bool* bp) const override;
virtual bool getBuiltinClass(JSContext* cx, HandleObject proxy,
ESClass* cls) const override;
virtual bool isArray(JSContext* cx, HandleObject proxy,
JS::IsArrayAnswer* answer) const override;
virtual const char* className(JSContext* cx,
HandleObject proxy) const override;
virtual JSString* fun_toString(JSContext* cx, HandleObject proxy,
bool isToSource) const override;
virtual RegExpShared* regexp_toShared(JSContext* cx,
HandleObject proxy) const override;
virtual bool boxedValue_unbox(JSContext* cx, HandleObject proxy,
MutableHandleValue vp) const override;
virtual bool isCallable(JSObject* obj) const override;
virtual bool isConstructor(JSObject* obj) const override;
};
/*
* A wrapper is a proxy with a target object to which it generally forwards
* operations, but may restrict access to certain operations or augment those
* operations in various ways.
*
* A wrapper can be "unwrapped" in C++, exposing the underlying object.
* Callers should be careful to avoid unwrapping security wrappers in the wrong
* context.
*
* Important: If you add a method implementation here, you probably also need
* to add an override in CrossCompartmentWrapper. If you don't, you risk
* compartment mismatches. See bug 945826 comment 0.
*/
class JS_FRIEND_API Wrapper : public ForwardingProxyHandler {
unsigned mFlags;
public:
explicit constexpr Wrapper(unsigned aFlags, bool aHasPrototype = false,
bool aHasSecurityPolicy = false)
: ForwardingProxyHandler(&family, aHasPrototype, aHasSecurityPolicy),
mFlags(aFlags) {}
virtual bool finalizeInBackground(const Value& priv) const override;
/**
* A hook subclasses can override to implement CheckedUnwrapDynamic
* behavior. The JSContext represents the "who is trying to unwrap?" Realm.
* The JSObject is the wrapper that the caller is trying to unwrap.
*/
virtual bool dynamicCheckedUnwrapAllowed(HandleObject obj,
JSContext* cx) const {
MOZ_ASSERT(hasSecurityPolicy(), "Why are you asking?");
return false;
}
using BaseProxyHandler::Action;
enum Flags { CROSS_COMPARTMENT = 1 << 0, LAST_USED_FLAG = CROSS_COMPARTMENT };
static JSObject* New(JSContext* cx, JSObject* obj, const Wrapper* handler,
const WrapperOptions& options = WrapperOptions());
static JSObject* Renew(JSObject* existing, JSObject* obj,
const Wrapper* handler);
static inline const Wrapper* wrapperHandler(const JSObject* wrapper);
static JSObject* wrappedObject(JSObject* wrapper);
unsigned flags() const { return mFlags; }
bool isCrossCompartmentWrapper() const {
return !!(mFlags & CROSS_COMPARTMENT);
}
static const char family;
static const Wrapper singleton;
static const Wrapper singletonWithPrototype;
static JSObject* const defaultProto;
};
inline JSObject* WrapperOptions::proto() const {
return proto_ ? *proto_ : Wrapper::defaultProto;
}
/* Base class for all cross compartment wrapper handlers. */
class JS_FRIEND_API CrossCompartmentWrapper : public Wrapper {
public:
explicit constexpr CrossCompartmentWrapper(unsigned aFlags,
bool aHasPrototype = false,
bool aHasSecurityPolicy = false)
: Wrapper(CROSS_COMPARTMENT | aFlags, aHasPrototype, aHasSecurityPolicy) {
}
/* Standard internal methods. */
virtual bool getOwnPropertyDescriptor(
JSContext* cx, HandleObject wrapper, HandleId id,
MutableHandle<PropertyDescriptor> desc) const override;
virtual bool defineProperty(JSContext* cx, HandleObject wrapper, HandleId id,
Handle<PropertyDescriptor> desc,
ObjectOpResult& result) const override;
virtual bool ownPropertyKeys(JSContext* cx, HandleObject wrapper,
AutoIdVector& props) const override;
virtual bool delete_(JSContext* cx, HandleObject wrapper, HandleId id,
ObjectOpResult& result) const override;
virtual JSObject* enumerate(JSContext* cx,
HandleObject wrapper) const override;
virtual bool getPrototype(JSContext* cx, HandleObject proxy,
MutableHandleObject protop) const override;
virtual bool setPrototype(JSContext* cx, HandleObject proxy,
HandleObject proto,
ObjectOpResult& result) const override;
virtual bool getPrototypeIfOrdinary(
JSContext* cx, HandleObject proxy, bool* isOrdinary,
MutableHandleObject protop) const override;
virtual bool setImmutablePrototype(JSContext* cx, HandleObject proxy,
bool* succeeded) const override;
virtual bool preventExtensions(JSContext* cx, HandleObject wrapper,
ObjectOpResult& result) const override;
virtual bool isExtensible(JSContext* cx, HandleObject wrapper,
bool* extensible) const override;
virtual bool has(JSContext* cx, HandleObject wrapper, HandleId id,
bool* bp) const override;
virtual bool get(JSContext* cx, HandleObject wrapper, HandleValue receiver,
HandleId id, MutableHandleValue vp) const override;
virtual bool set(JSContext* cx, HandleObject wrapper, HandleId id,
HandleValue v, HandleValue receiver,
ObjectOpResult& result) const override;
virtual bool call(JSContext* cx, HandleObject wrapper,
const CallArgs& args) const override;
virtual bool construct(JSContext* cx, HandleObject wrapper,
const CallArgs& args) const override;
/* SpiderMonkey extensions. */
virtual bool hasOwn(JSContext* cx, HandleObject wrapper, HandleId id,
bool* bp) const override;
virtual bool getOwnEnumerablePropertyKeys(JSContext* cx, HandleObject wrapper,
AutoIdVector& props) const override;
virtual bool nativeCall(JSContext* cx, IsAcceptableThis test, NativeImpl impl,
const CallArgs& args) const override;
virtual bool hasInstance(JSContext* cx, HandleObject wrapper,
MutableHandleValue v, bool* bp) const override;
virtual const char* className(JSContext* cx,
HandleObject proxy) const override;
virtual JSString* fun_toString(JSContext* cx, HandleObject wrapper,
bool isToSource) const override;
virtual RegExpShared* regexp_toShared(JSContext* cx,
HandleObject proxy) const override;
virtual bool boxedValue_unbox(JSContext* cx, HandleObject proxy,
MutableHandleValue vp) const override;
// Allocate CrossCompartmentWrappers in the nursery.
virtual bool canNurseryAllocate() const override { return true; }
static const CrossCompartmentWrapper singleton;
static const CrossCompartmentWrapper singletonWithPrototype;
};
class JS_FRIEND_API OpaqueCrossCompartmentWrapper
: public CrossCompartmentWrapper {
public:
explicit constexpr OpaqueCrossCompartmentWrapper()
: CrossCompartmentWrapper(0) {}
/* Standard internal methods. */
virtual bool getOwnPropertyDescriptor(
JSContext* cx, HandleObject wrapper, HandleId id,
MutableHandle<PropertyDescriptor> desc) const override;
virtual bool defineProperty(JSContext* cx, HandleObject wrapper, HandleId id,
Handle<PropertyDescriptor> desc,
ObjectOpResult& result) const override;
virtual bool ownPropertyKeys(JSContext* cx, HandleObject wrapper,
AutoIdVector& props) const override;
virtual bool delete_(JSContext* cx, HandleObject wrapper, HandleId id,
ObjectOpResult& result) const override;
virtual JSObject* enumerate(JSContext* cx,
HandleObject wrapper) const override;
virtual bool getPrototype(JSContext* cx, HandleObject wrapper,
MutableHandleObject protop) const override;
virtual bool setPrototype(JSContext* cx, HandleObject wrapper,
HandleObject proto,
ObjectOpResult& result) const override;
virtual bool getPrototypeIfOrdinary(
JSContext* cx, HandleObject wrapper, bool* isOrdinary,
MutableHandleObject protop) const override;
virtual bool setImmutablePrototype(JSContext* cx, HandleObject wrapper,
bool* succeeded) const override;
virtual bool preventExtensions(JSContext* cx, HandleObject wrapper,
ObjectOpResult& result) const override;
virtual bool isExtensible(JSContext* cx, HandleObject wrapper,
bool* extensible) const override;
virtual bool has(JSContext* cx, HandleObject wrapper, HandleId id,
bool* bp) const override;
virtual bool get(JSContext* cx, HandleObject wrapper, HandleValue receiver,
HandleId id, MutableHandleValue vp) const override;
virtual bool set(JSContext* cx, HandleObject wrapper, HandleId id,
HandleValue v, HandleValue receiver,
ObjectOpResult& result) const override;
virtual bool call(JSContext* cx, HandleObject wrapper,
const CallArgs& args) const override;
virtual bool construct(JSContext* cx, HandleObject wrapper,
const CallArgs& args) const override;
/* SpiderMonkey extensions. */
virtual bool hasOwn(JSContext* cx, HandleObject wrapper, HandleId id,
bool* bp) const override;
virtual bool getOwnEnumerablePropertyKeys(JSContext* cx, HandleObject wrapper,
AutoIdVector& props) const override;
virtual bool getBuiltinClass(JSContext* cx, HandleObject wrapper,
ESClass* cls) const override;
virtual bool isArray(JSContext* cx, HandleObject obj,
JS::IsArrayAnswer* answer) const override;
virtual bool hasInstance(JSContext* cx, HandleObject wrapper,
MutableHandleValue v, bool* bp) const override;
virtual const char* className(JSContext* cx,
HandleObject wrapper) const override;
virtual JSString* fun_toString(JSContext* cx, HandleObject proxy,
bool isToSource) const override;
static const OpaqueCrossCompartmentWrapper singleton;
};
/*
* Base class for security wrappers. A security wrapper is potentially hiding
* all or part of some wrapped object thus SecurityWrapper defaults to denying
* access to the wrappee. This is the opposite of Wrapper which tries to be
* completely transparent.
*
* NB: Currently, only a few ProxyHandler operations are overridden to deny
* access, relying on derived SecurityWrapper to block access when necessary.
*/
template <class Base>
class JS_FRIEND_API SecurityWrapper : public Base {
public:
explicit constexpr SecurityWrapper(unsigned flags, bool hasPrototype = false)
: Base(flags, hasPrototype, /* hasSecurityPolicy = */ true) {}
virtual bool enter(JSContext* cx, HandleObject wrapper, HandleId id,
Wrapper::Action act, bool mayThrow,
bool* bp) const override;
virtual bool defineProperty(JSContext* cx, HandleObject wrapper, HandleId id,
Handle<PropertyDescriptor> desc,
ObjectOpResult& result) const override;
virtual bool isExtensible(JSContext* cx, HandleObject wrapper,
bool* extensible) const override;
virtual bool preventExtensions(JSContext* cx, HandleObject wrapper,
ObjectOpResult& result) const override;
virtual bool setPrototype(JSContext* cx, HandleObject proxy,
HandleObject proto,
ObjectOpResult& result) const override;
virtual bool setImmutablePrototype(JSContext* cx, HandleObject proxy,
bool* succeeded) const override;
virtual bool nativeCall(JSContext* cx, IsAcceptableThis test, NativeImpl impl,
const CallArgs& args) const override;
virtual bool getBuiltinClass(JSContext* cx, HandleObject wrapper,
ESClass* cls) const override;
virtual bool isArray(JSContext* cx, HandleObject wrapper,
JS::IsArrayAnswer* answer) const override;
virtual RegExpShared* regexp_toShared(JSContext* cx,
HandleObject proxy) const override;
virtual bool boxedValue_unbox(JSContext* cx, HandleObject proxy,
MutableHandleValue vp) const override;
// Allow isCallable and isConstructor. They used to be class-level, and so
// could not be guarded against.
/*
* Allow our subclasses to select the superclass behavior they want without
* needing to specify an exact superclass.
*/
typedef Base Permissive;
typedef SecurityWrapper<Base> Restrictive;
};
typedef SecurityWrapper<CrossCompartmentWrapper>
CrossCompartmentSecurityWrapper;
extern JSObject* TransparentObjectWrapper(JSContext* cx, HandleObject existing,
HandleObject obj);
inline bool IsWrapper(const JSObject* obj) {
return IsProxy(obj) && GetProxyHandler(obj)->family() == &Wrapper::family;
}
inline bool IsCrossCompartmentWrapper(const JSObject* obj) {
return IsWrapper(obj) &&
(Wrapper::wrapperHandler(obj)->flags() & Wrapper::CROSS_COMPARTMENT);
}
/* static */ inline const Wrapper* Wrapper::wrapperHandler(
const JSObject* wrapper) {
MOZ_ASSERT(IsWrapper(wrapper));
return static_cast<const Wrapper*>(GetProxyHandler(wrapper));
}
// Given a JSObject, returns that object stripped of wrappers. If
// stopAtWindowProxy is true, then this returns the WindowProxy if it was
// previously wrapped. Otherwise, this returns the first object for which
// JSObject::isWrapper returns false.
//
// ExposeToActiveJS is called on wrapper targets to allow gray marking
// assertions to work while an incremental GC is in progress, but this means
// that this cannot be called from the GC or off the main thread.
JS_FRIEND_API JSObject* UncheckedUnwrap(JSObject* obj,
bool stopAtWindowProxy = true,
unsigned* flagsp = nullptr);
// Given a JSObject, returns that object stripped of wrappers, except
// WindowProxy wrappers. At each stage, the wrapper has the opportunity to veto
// the unwrap. Null is returned if there are security wrappers that can't be
// unwrapped.
//
// This does a static-only unwrap check: it basically checks whether _all_
// globals in the wrapper's source compartment should be able to access the
// wrapper target. This won't necessarily return the right thing for the HTML
// spec's cross-origin objects (WindowProxy and Location), but is fine to use
// when failure to unwrap one of those objects wouldn't be a problem. For
// example, if you want to test whether your target object is a specific class
// that's not WindowProxy or Location, you can use this.
//
// ExposeToActiveJS is called on wrapper targets to allow gray marking
// assertions to work while an incremental GC is in progress, but this means
// that this cannot be called from the GC or off the main thread.
JS_FRIEND_API JSObject* CheckedUnwrapStatic(JSObject* obj);
// Old CheckedUnwrap API that we would like to remove once we convert all
// callers to CheckedUnwrapStatic or CheckedUnwrapDynamic. If stopAtWindowProxy
// is true, then this returns the WindowProxy if a WindowProxy is encountered;
// otherwise it will unwrap the WindowProxy and return a Window.
JS_FRIEND_API JSObject* CheckedUnwrap(JSObject* obj,
bool stopAtWindowProxy = true);
// Unwrap only the outermost security wrapper, with the same semantics as
// above. This is the checked version of Wrapper::wrappedObject.
JS_FRIEND_API JSObject* UnwrapOneChecked(JSObject* obj,
bool stopAtWindowProxy = true);
// Given a JSObject, returns that object stripped of wrappers. At each stage,
// the security wrapper has the opportunity to veto the unwrap. If
// stopAtWindowProxy is true, then this returns the WindowProxy if it was
// previously wrapped. Null is returned if there are security wrappers that
// can't be unwrapped.
//
// ExposeToActiveJS is called on wrapper targets to allow gray marking
// assertions to work while an incremental GC is in progress, but this means
// that this cannot be called from the GC or off the main thread.
//
// The JSContext argument will be used for dynamic checks (needed by WindowProxy
// and Location) and should represent the Realm doing the unwrapping. It is not
// used to throw exceptions; this function never throws.
//
// This function may be able to GC (and the static analysis definitely thinks it
// can), but it still takes a JSObject* argument, because some of its callers
// would actually have a bit of a hard time producing a Rooted. And it ends up
// having to root internally anyway, because it wants to use the value in a loop
// and you can't assign to a HandleObject. What this means is that callers who
// plan to use the argument object after they have called this function will
// need to root it to avoid hazard failures, even though this function doesn't
// require a Handle.
JS_FRIEND_API JSObject* CheckedUnwrapDynamic(JSObject* obj, JSContext* cx,
bool stopAtWindowProxy = true);
// Unwrap only the outermost security wrapper, with the same semantics as
// above. This is the checked version of Wrapper::wrappedObject.
JS_FRIEND_API JSObject* UnwrapOneCheckedDynamic(HandleObject obj, JSContext* cx,
bool stopAtWindowProxy = true);
// Given a JSObject, returns that object stripped of wrappers. This returns the
// WindowProxy if it was previously wrapped.
//
// ExposeToActiveJS is not called on wrapper targets so this can be called from
// the GC or off the main thread.
JS_FRIEND_API JSObject* UncheckedUnwrapWithoutExpose(JSObject* obj);
void ReportAccessDenied(JSContext* cx);
JS_FRIEND_API void NukeCrossCompartmentWrapper(JSContext* cx,
JSObject* wrapper);
// If a cross-compartment wrapper source => target exists, nuke it.
JS_FRIEND_API void NukeCrossCompartmentWrapperIfExists(JSContext* cx,
JS::Compartment* source,
JSObject* target);
void RemapWrapper(JSContext* cx, JSObject* wobj, JSObject* newTarget);
JS_FRIEND_API bool RemapAllWrappersForObject(JSContext* cx, JSObject* oldTarget,
JSObject* newTarget);
// API to recompute all cross-compartment wrappers whose source and target
// match the given filters.
JS_FRIEND_API bool RecomputeWrappers(JSContext* cx,
const CompartmentFilter& sourceFilter,
const CompartmentFilter& targetFilter);
} /* namespace js */
#endif /* js_Wrapper_h */