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
#include "XrayWrapper.h"
#include "AccessCheck.h"
#include "WrapperFactory.h"
#include "nsDependentString.h"
#include "nsIConsoleService.h"
#include "nsIScriptError.h"
#include "xpcprivate.h"
#include "jsapi.h"
#include "js/CallAndConstruct.h" // JS::Call, JS::Construct, JS::IsCallable
#include "js/ColumnNumber.h" // JS::ColumnNumberOneOrigin
#include "js/experimental/TypedData.h" // JS_GetTypedArrayLength
#include "js/friend/WindowProxy.h" // js::IsWindowProxy
#include "js/friend/XrayJitInfo.h" // JS::XrayJitInfo
#include "js/Object.h" // JS::GetClass, JS::GetCompartment, JS::GetReservedSlot, JS::SetReservedSlot
#include "js/PropertyAndElement.h" // JS_AlreadyHasOwnPropertyById, JS_DefineProperty, JS_DefinePropertyById, JS_DeleteProperty, JS_DeletePropertyById, JS_HasProperty, JS_HasPropertyById
#include "js/PropertyDescriptor.h" // JS::PropertyDescriptor, JS_GetOwnPropertyDescriptorById, JS_GetPropertyDescriptorById
#include "js/PropertySpec.h"
#include "nsGlobalWindowInner.h"
#include "nsJSUtils.h"
#include "nsPrintfCString.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/ProxyHandlerUtils.h"
#include "mozilla/dom/WindowProxyHolder.h"
#include "mozilla/dom/XrayExpandoClass.h"
using namespace mozilla::dom;
using namespace JS;
using namespace mozilla;
using js::BaseProxyHandler;
using js::CheckedUnwrapStatic;
using js::IsCrossCompartmentWrapper;
using js::UncheckedUnwrap;
using js::Wrapper;
namespace xpc {
#define Between(x, a, b) (a <= x && x <= b)
static_assert(JSProto_URIError - JSProto_Error == 8,
"New prototype added in error object range");
#define AssertErrorObjectKeyInBounds(key) \
static_assert(Between(key, JSProto_Error, JSProto_URIError), \
"We depend on js/ProtoKey.h ordering here");
MOZ_FOR_EACH(AssertErrorObjectKeyInBounds, (),
(JSProto_Error, JSProto_InternalError, JSProto_AggregateError,
JSProto_EvalError, JSProto_RangeError, JSProto_ReferenceError,
JSProto_SyntaxError, JSProto_TypeError, JSProto_URIError));
static_assert(JSProto_Uint8ClampedArray - JSProto_Int8Array == 8,
"New prototype added in typed array range");
#define AssertTypedArrayKeyInBounds(key) \
static_assert(Between(key, JSProto_Int8Array, JSProto_Uint8ClampedArray), \
"We depend on js/ProtoKey.h ordering here");
MOZ_FOR_EACH(AssertTypedArrayKeyInBounds, (),
(JSProto_Int8Array, JSProto_Uint8Array, JSProto_Int16Array,
JSProto_Uint16Array, JSProto_Int32Array, JSProto_Uint32Array,
JSProto_Float32Array, JSProto_Float64Array,
JSProto_Uint8ClampedArray));
#undef Between
inline bool IsErrorObjectKey(JSProtoKey key) {
return key >= JSProto_Error && key <= JSProto_URIError;
}
inline bool IsTypedArrayKey(JSProtoKey key) {
return key >= JSProto_Int8Array && key <= JSProto_Uint8ClampedArray;
}
// Whitelist for the standard ES classes we can Xray to.
static bool IsJSXraySupported(JSProtoKey key) {
if (IsTypedArrayKey(key)) {
return true;
}
if (IsErrorObjectKey(key)) {
return true;
}
switch (key) {
case JSProto_Date:
case JSProto_DataView:
case JSProto_Object:
case JSProto_Array:
case JSProto_Function:
case JSProto_BoundFunction:
case JSProto_TypedArray:
case JSProto_SavedFrame:
case JSProto_RegExp:
case JSProto_Promise:
case JSProto_ArrayBuffer:
case JSProto_SharedArrayBuffer:
case JSProto_Map:
case JSProto_Set:
case JSProto_WeakMap:
case JSProto_WeakSet:
return true;
default:
return false;
}
}
XrayType GetXrayType(JSObject* obj) {
obj = js::UncheckedUnwrap(obj, /* stopAtWindowProxy = */ false);
if (mozilla::dom::UseDOMXray(obj)) {
return XrayForDOMObject;
}
MOZ_ASSERT(!js::IsWindowProxy(obj));
JSProtoKey standardProto = IdentifyStandardInstanceOrPrototype(obj);
if (IsJSXraySupported(standardProto)) {
return XrayForJSObject;
}
// Modulo a few exceptions, everything else counts as an XrayWrapper to an
// opaque object, which means that more-privileged code sees nothing from
// the underlying object. This is very important for security. In some cases
// though, we need to make an exception for compatibility.
if (IsSandbox(obj)) {
return NotXray;
}
return XrayForOpaqueObject;
}
JSObject* XrayAwareCalleeGlobal(JSObject* fun) {
MOZ_ASSERT(js::IsFunctionObject(fun));
if (!js::FunctionHasNativeReserved(fun)) {
// Just a normal function, no Xrays involved.
return JS::GetNonCCWObjectGlobal(fun);
}
// The functions we expect here have the Xray wrapper they're associated with
// in their XRAY_DOM_FUNCTION_PARENT_WRAPPER_SLOT and, in a debug build,
// themselves in their XRAY_DOM_FUNCTION_NATIVE_SLOT_FOR_SELF. Assert that
// last bit.
MOZ_ASSERT(&js::GetFunctionNativeReserved(
fun, XRAY_DOM_FUNCTION_NATIVE_SLOT_FOR_SELF)
.toObject() == fun);
Value v =
js::GetFunctionNativeReserved(fun, XRAY_DOM_FUNCTION_PARENT_WRAPPER_SLOT);
MOZ_ASSERT(IsXrayWrapper(&v.toObject()));
JSObject* xrayTarget = js::UncheckedUnwrap(&v.toObject());
return JS::GetNonCCWObjectGlobal(xrayTarget);
}
JSObject* XrayTraits::getExpandoChain(HandleObject obj) {
return ObjectScope(obj)->GetExpandoChain(obj);
}
JSObject* XrayTraits::detachExpandoChain(HandleObject obj) {
return ObjectScope(obj)->DetachExpandoChain(obj);
}
bool XrayTraits::setExpandoChain(JSContext* cx, HandleObject obj,
HandleObject chain) {
return ObjectScope(obj)->SetExpandoChain(cx, obj, chain);
}
const JSClass XrayTraits::HolderClass = {
"XrayHolder", JSCLASS_HAS_RESERVED_SLOTS(HOLDER_SHARED_SLOT_COUNT)};
const JSClass JSXrayTraits::HolderClass = {
"JSXrayHolder", JSCLASS_HAS_RESERVED_SLOTS(SLOT_COUNT)};
bool OpaqueXrayTraits::resolveOwnProperty(
JSContext* cx, HandleObject wrapper, HandleObject target,
HandleObject holder, HandleId id,
MutableHandle<Maybe<PropertyDescriptor>> desc) {
bool ok =
XrayTraits::resolveOwnProperty(cx, wrapper, target, holder, id, desc);
if (!ok || desc.isSome()) {
return ok;
}
return ReportWrapperDenial(cx, id, WrapperDenialForXray,
"object is not safely Xrayable");
}
bool ReportWrapperDenial(JSContext* cx, HandleId id, WrapperDenialType type,
const char* reason) {
RealmPrivate* priv = RealmPrivate::Get(CurrentGlobalOrNull(cx));
bool alreadyWarnedOnce = priv->wrapperDenialWarnings[type];
priv->wrapperDenialWarnings[type] = true;
// The browser console warning is only emitted for the first violation,
// whereas the (debug-only) NS_WARNING is emitted for each violation.
#ifndef DEBUG
if (alreadyWarnedOnce) {
return true;
}
#endif
nsAutoJSString propertyName;
RootedValue idval(cx);
if (!JS_IdToValue(cx, id, &idval)) {
return false;
}
JSString* str = JS_ValueToSource(cx, idval);
if (!str) {
return false;
}
if (!propertyName.init(cx, str)) {
return false;
}
AutoFilename filename;
uint32_t line = 0;
JS::ColumnNumberOneOrigin column;
DescribeScriptedCaller(cx, &filename, &line, &column);
// Warn to the terminal for the logs.
NS_WARNING(
nsPrintfCString("Silently denied access to property %s: %s (@%s:%u:%u)",
NS_LossyConvertUTF16toASCII(propertyName).get(), reason,
filename.get(), line, column.oneOriginValue())
.get());
// If this isn't the first warning on this topic for this global, we've
// already bailed out in opt builds. Now that the NS_WARNING is done, bail
// out in debug builds as well.
if (alreadyWarnedOnce) {
return true;
}
//
// Log a message to the console service.
//
// Grab the pieces.
nsCOMPtr<nsIConsoleService> consoleService =
do_GetService(NS_CONSOLESERVICE_CONTRACTID);
NS_ENSURE_TRUE(consoleService, true);
nsCOMPtr<nsIScriptError> errorObject =
do_CreateInstance(NS_SCRIPTERROR_CONTRACTID);
NS_ENSURE_TRUE(errorObject, true);
// Compute the current window id if any.
uint64_t windowId = 0;
if (nsGlobalWindowInner* win = CurrentWindowOrNull(cx)) {
windowId = win->WindowID();
}
Maybe<nsPrintfCString> errorMessage;
if (type == WrapperDenialForXray) {
errorMessage.emplace(
"XrayWrapper denied access to property %s (reason: %s). "
"for more information. Note that only the first denied "
"property access from a given global object will be reported.",
NS_LossyConvertUTF16toASCII(propertyName).get(), reason);
} else {
MOZ_ASSERT(type == WrapperDenialForCOW);
errorMessage.emplace(
"Security wrapper denied access to property %s on privileged "
"Javascript object. Note that only the first denied property "
"access from a given global object will be reported.",
NS_LossyConvertUTF16toASCII(propertyName).get());
}
nsString filenameStr(NS_ConvertASCIItoUTF16(filename.get()));
nsresult rv = errorObject->InitWithWindowID(
NS_ConvertASCIItoUTF16(errorMessage.ref()), filenameStr, u""_ns, line,
column.oneOriginValue(), nsIScriptError::warningFlag, "XPConnect",
windowId);
NS_ENSURE_SUCCESS(rv, true);
rv = consoleService->LogMessage(errorObject);
NS_ENSURE_SUCCESS(rv, true);
return true;
}
bool JSXrayTraits::getOwnPropertyFromWrapperIfSafe(
JSContext* cx, HandleObject wrapper, HandleId id,
MutableHandle<Maybe<PropertyDescriptor>> outDesc) {
MOZ_ASSERT(js::IsObjectInContextCompartment(wrapper, cx));
RootedObject target(cx, getTargetObject(wrapper));
RootedObject wrapperGlobal(cx, JS::CurrentGlobalOrNull(cx));
{
JSAutoRealm ar(cx, target);
JS_MarkCrossZoneId(cx, id);
if (!getOwnPropertyFromTargetIfSafe(cx, target, wrapper, wrapperGlobal, id,
outDesc)) {
return false;
}
}
return JS_WrapPropertyDescriptor(cx, outDesc);
}
bool JSXrayTraits::getOwnPropertyFromTargetIfSafe(
JSContext* cx, HandleObject target, HandleObject wrapper,
HandleObject wrapperGlobal, HandleId id,
MutableHandle<Maybe<PropertyDescriptor>> outDesc) {
// Note - This function operates in the target compartment, because it
// avoids a bunch of back-and-forth wrapping in enumerateNames.
MOZ_ASSERT(getTargetObject(wrapper) == target);
MOZ_ASSERT(js::IsObjectInContextCompartment(target, cx));
MOZ_ASSERT(WrapperFactory::IsXrayWrapper(wrapper));
MOZ_ASSERT(JS_IsGlobalObject(wrapperGlobal));
js::AssertSameCompartment(wrapper, wrapperGlobal);
MOZ_ASSERT(outDesc.isNothing());
Rooted<Maybe<PropertyDescriptor>> desc(cx);
if (!JS_GetOwnPropertyDescriptorById(cx, target, id, &desc)) {
return false;
}
// If the property doesn't exist at all, we're done.
if (desc.isNothing()) {
return true;
}
// Disallow accessor properties.
if (desc->isAccessorDescriptor()) {
JSAutoRealm ar(cx, wrapperGlobal);
JS_MarkCrossZoneId(cx, id);
return ReportWrapperDenial(cx, id, WrapperDenialForXray,
"property has accessor");
}
// Apply extra scrutiny to objects.
if (desc->value().isObject()) {
RootedObject propObj(cx, js::UncheckedUnwrap(&desc->value().toObject()));
JSAutoRealm ar(cx, propObj);
// Disallow non-subsumed objects.
if (!AccessCheck::subsumes(target, propObj)) {
JSAutoRealm ar(cx, wrapperGlobal);
JS_MarkCrossZoneId(cx, id);
return ReportWrapperDenial(cx, id, WrapperDenialForXray,
"value not same-origin with target");
}
// Disallow non-Xrayable objects.
XrayType xrayType = GetXrayType(propObj);
if (xrayType == NotXray || xrayType == XrayForOpaqueObject) {
JSAutoRealm ar(cx, wrapperGlobal);
JS_MarkCrossZoneId(cx, id);
return ReportWrapperDenial(cx, id, WrapperDenialForXray,
"value not Xrayable");
}
// Disallow callables.
if (JS::IsCallable(propObj)) {
JSAutoRealm ar(cx, wrapperGlobal);
JS_MarkCrossZoneId(cx, id);
return ReportWrapperDenial(cx, id, WrapperDenialForXray,
"value is callable");
}
}
// Disallow any property that shadows something on its (Xrayed)
// prototype chain.
JSAutoRealm ar2(cx, wrapperGlobal);
JS_MarkCrossZoneId(cx, id);
RootedObject proto(cx);
bool foundOnProto = false;
if (!JS_GetPrototype(cx, wrapper, &proto) ||
(proto && !JS_HasPropertyById(cx, proto, id, &foundOnProto))) {
return false;
}
if (foundOnProto) {
return ReportWrapperDenial(
cx, id, WrapperDenialForXray,
"value shadows a property on the standard prototype");
}
// We made it! Assign over the descriptor, and don't forget to wrap.
outDesc.set(desc);
return true;
}
// Returns true on success (in the JSAPI sense), false on failure. If true is
// returned, desc.object() will indicate whether we actually resolved
// the property.
//
// id is the property id we're looking for.
// holder is the object to define the property on.
// fs is the relevant JSFunctionSpec*.
// ps is the relevant JSPropertySpec*.
// desc is the descriptor we're resolving into.
static bool TryResolvePropertyFromSpecs(
JSContext* cx, HandleId id, HandleObject holder, const JSFunctionSpec* fs,
const JSPropertySpec* ps, MutableHandle<Maybe<PropertyDescriptor>> desc) {
// Scan through the functions.
const JSFunctionSpec* fsMatch = nullptr;
for (; fs && fs->name; ++fs) {
if (PropertySpecNameEqualsId(fs->name, id)) {
fsMatch = fs;
break;
}
}
if (fsMatch) {
// Generate an Xrayed version of the method.
RootedFunction fun(cx, JS::NewFunctionFromSpec(cx, fsMatch, id));
if (!fun) {
return false;
}
// The generic Xray machinery only defines non-own properties of the target
// on the holder. This is broken, and will be fixed at some point, but for
// now we need to cache the value explicitly. See the corresponding call to
// JS_GetOwnPropertyDescriptorById at the top of
// JSXrayTraits::resolveOwnProperty.
RootedObject funObj(cx, JS_GetFunctionObject(fun));
return JS_DefinePropertyById(cx, holder, id, funObj, 0) &&
JS_GetOwnPropertyDescriptorById(cx, holder, id, desc);
}
// Scan through the properties.
const JSPropertySpec* psMatch = nullptr;
for (; ps && ps->name; ++ps) {
if (PropertySpecNameEqualsId(ps->name, id)) {
psMatch = ps;
break;
}
}
if (psMatch) {
// The generic Xray machinery only defines non-own properties on the holder.
// This is broken, and will be fixed at some point, but for now we need to
// cache the value explicitly. See the corresponding call to
// JS_GetPropertyById at the top of JSXrayTraits::resolveOwnProperty.
//
// Note also that the public-facing API here doesn't give us a way to
// pass along JITInfo. It's probably ok though, since Xrays are already
// pretty slow.
unsigned attrs = psMatch->attributes();
if (psMatch->isAccessor()) {
if (psMatch->isSelfHosted()) {
JSFunction* getterFun = JS::GetSelfHostedFunction(
cx, psMatch->u.accessors.getter.selfHosted.funname, id, 0);
if (!getterFun) {
return false;
}
RootedObject getterObj(cx, JS_GetFunctionObject(getterFun));
RootedObject setterObj(cx);
if (psMatch->u.accessors.setter.selfHosted.funname) {
JSFunction* setterFun = JS::GetSelfHostedFunction(
cx, psMatch->u.accessors.setter.selfHosted.funname, id, 0);
if (!setterFun) {
return false;
}
setterObj = JS_GetFunctionObject(setterFun);
}
if (!JS_DefinePropertyById(cx, holder, id, getterObj, setterObj,
attrs)) {
return false;
}
} else {
if (!JS_DefinePropertyById(
cx, holder, id, psMatch->u.accessors.getter.native.op,
psMatch->u.accessors.setter.native.op, attrs)) {
return false;
}
}
} else {
RootedValue v(cx);
if (!psMatch->getValue(cx, &v)) {
return false;
}
if (!JS_DefinePropertyById(cx, holder, id, v, attrs)) {
return false;
}
}
return JS_GetOwnPropertyDescriptorById(cx, holder, id, desc);
}
return true;
}
static bool ShouldResolvePrototypeProperty(JSProtoKey key) {
// Proxy constructors have no "prototype" property.
return key != JSProto_Proxy;
}
static bool ShouldResolveStaticProperties(JSProtoKey key) {
if (!IsJSXraySupported(key)) {
// If we can't Xray this ES class, then we can't resolve statics on it.
return false;
}
// Don't try to resolve static properties on RegExp, because they
// have issues. In particular, some of them grab state off the
// global of the RegExp constructor that describes the last regexp
// evaluation in that global, which is not a useful thing to do
// over Xrays.
return key != JSProto_RegExp;
}
bool JSXrayTraits::resolveOwnProperty(
JSContext* cx, HandleObject wrapper, HandleObject target,
HandleObject holder, HandleId id,
MutableHandle<Maybe<PropertyDescriptor>> desc) {
// Call the common code.
bool ok =
XrayTraits::resolveOwnProperty(cx, wrapper, target, holder, id, desc);
if (!ok || desc.isSome()) {
return ok;
}
// The non-HasPrototypes semantics implemented by traditional Xrays are kind
// of broken with respect to |own|-ness and the holder. The common code
// muddles through by only checking the holder for non-|own| lookups, but
// that doesn't work for us. So we do an explicit holder check here, and hope
// that this mess gets fixed up soon.
if (!JS_GetOwnPropertyDescriptorById(cx, holder, id, desc)) {
return false;
}
if (desc.isSome()) {
return true;
}
JSProtoKey key = getProtoKey(holder);
if (!isPrototype(holder)) {
// For Object and Array instances, we expose some properties from the
// underlying object, but only after filtering them carefully.
//
// Note that, as far as JS observables go, Arrays are just Objects with
// a different prototype and a magic (own, non-configurable) |.length| that
// serves as a non-tight upper bound on |own| indexed properties. So while
// it's tempting to try to impose some sort of structure on what Arrays
// "should" look like over Xrays, the underlying object is squishy enough
// that it makes sense to just treat them like Objects for Xray purposes.
if (key == JSProto_Object || key == JSProto_Array) {
return getOwnPropertyFromWrapperIfSafe(cx, wrapper, id, desc);
}
if (IsTypedArrayKey(key)) {
if (IsArrayIndex(GetArrayIndexFromId(id))) {
// WebExtensions can't use cloneInto(), so we just let them do
// the slow thing to maximize compatibility.
if (CompartmentPrivate::Get(CurrentGlobalOrNull(cx))
->isWebExtensionContentScript) {
Rooted<Maybe<PropertyDescriptor>> innerDesc(cx);
{
JSAutoRealm ar(cx, target);
JS_MarkCrossZoneId(cx, id);
if (!JS_GetOwnPropertyDescriptorById(cx, target, id, &innerDesc)) {
return false;
}
}
if (innerDesc.isSome() && innerDesc->isDataDescriptor() &&
innerDesc->value().isNumber()) {
desc.set(innerDesc);
}
return true;
}
JS_ReportErrorASCII(
cx,
"Accessing TypedArray data over Xrays is slow, and forbidden "
"in order to encourage performant code. To copy TypedArrays "
"across origin boundaries, consider using "
"Components.utils.cloneInto().");
return false;
}
} else if (key == JSProto_Function) {
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_LENGTH)) {
uint16_t length;
RootedFunction fun(cx, JS_GetObjectFunction(target));
{
JSAutoRealm ar(cx, target);
if (!JS_GetFunctionLength(cx, fun, &length)) {
return false;
}
}
desc.set(Some(PropertyDescriptor::Data(NumberValue(length), {})));
return true;
}
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_NAME)) {
JS::Rooted<JSFunction*> fun(cx, JS_GetObjectFunction(target));
JS::Rooted<JSString*> fname(cx);
if (!JS_GetFunctionId(cx, fun, &fname)) {
return false;
}
if (fname) {
JS_MarkCrossZoneIdValue(cx, StringValue(fname));
}
desc.set(Some(PropertyDescriptor::Data(
fname ? StringValue(fname) : JS_GetEmptyStringValue(cx), {})));
} else {
// Look for various static properties/methods and the
// 'prototype' property.
JSProtoKey standardConstructor = constructorFor(holder);
if (standardConstructor != JSProto_Null) {
// Handle the 'prototype' property to make
// xrayedGlobal.StandardClass.prototype work.
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_PROTOTYPE) &&
ShouldResolvePrototypeProperty(standardConstructor)) {
RootedObject standardProto(cx);
{
JSAutoRealm ar(cx, target);
if (!JS_GetClassPrototype(cx, standardConstructor,
&standardProto)) {
return false;
}
MOZ_ASSERT(standardProto);
}
if (!JS_WrapObject(cx, &standardProto)) {
return false;
}
desc.set(Some(
PropertyDescriptor::Data(ObjectValue(*standardProto), {})));
return true;
}
if (ShouldResolveStaticProperties(standardConstructor)) {
const JSClass* clasp = js::ProtoKeyToClass(standardConstructor);
MOZ_ASSERT(clasp->specDefined());
if (!TryResolvePropertyFromSpecs(
cx, id, holder, clasp->specConstructorFunctions(),
clasp->specConstructorProperties(), desc)) {
return false;
}
if (desc.isSome()) {
return true;
}
}
}
}
} else if (IsErrorObjectKey(key)) {
// The useful state of error objects (except for .stack) is
// (unfortunately) represented as own data properties per-spec. This
// means that we can't have a a clean representation of the data
// (free from tampering) without doubling the slots of Error
// objects, which isn't great. So we forward these properties to the
// underlying object and then just censor any values with the wrong
// type. This limits the ability of content to do anything all that
// confusing.
bool isErrorIntProperty =
id == GetJSIDByIndex(cx, XPCJSContext::IDX_LINENUMBER) ||
id == GetJSIDByIndex(cx, XPCJSContext::IDX_COLUMNNUMBER);
bool isErrorStringProperty =
id == GetJSIDByIndex(cx, XPCJSContext::IDX_FILENAME) ||
id == GetJSIDByIndex(cx, XPCJSContext::IDX_MESSAGE);
if (isErrorIntProperty || isErrorStringProperty) {
RootedObject waiver(cx, wrapper);
if (!WrapperFactory::WaiveXrayAndWrap(cx, &waiver)) {
return false;
}
if (!JS_GetOwnPropertyDescriptorById(cx, waiver, id, desc)) {
return false;
}
if (desc.isSome()) {
// Make sure the property has the expected type.
if (!desc->isDataDescriptor() ||
(isErrorIntProperty && !desc->value().isInt32()) ||
(isErrorStringProperty && !desc->value().isString())) {
desc.reset();
}
}
return true;
}
#if defined(NIGHTLY_BUILD)
// The optional .cause property can have any value.
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_CAUSE)) {
return getOwnPropertyFromWrapperIfSafe(cx, wrapper, id, desc);
}
#endif
if (key == JSProto_AggregateError &&
id == GetJSIDByIndex(cx, XPCJSContext::IDX_ERRORS)) {
return getOwnPropertyFromWrapperIfSafe(cx, wrapper, id, desc);
}
} else if (key == JSProto_RegExp) {
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_LASTINDEX)) {
return getOwnPropertyFromWrapperIfSafe(cx, wrapper, id, desc);
}
} else if (key == JSProto_BoundFunction) {
// Bound functions have configurable .name and .length own data
// properties. Only support string values for .name and number values for
// .length.
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_NAME)) {
if (!getOwnPropertyFromWrapperIfSafe(cx, wrapper, id, desc)) {
return false;
}
if (desc.isSome() &&
(!desc->isDataDescriptor() || !desc->value().isString())) {
desc.reset();
}
return true;
}
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_LENGTH)) {
if (!getOwnPropertyFromWrapperIfSafe(cx, wrapper, id, desc)) {
return false;
}
if (desc.isSome() &&
(!desc->isDataDescriptor() || !desc->value().isNumber())) {
desc.reset();
}
return true;
}
}
// The rest of this function applies only to prototypes.
return true;
}
// Handle the 'constructor' property.
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_CONSTRUCTOR)) {
RootedObject constructor(cx);
{
JSAutoRealm ar(cx, target);
if (!JS_GetClassObject(cx, key, &constructor)) {
return false;
}
}
if (!JS_WrapObject(cx, &constructor)) {
return false;
}
desc.set(Some(PropertyDescriptor::Data(
ObjectValue(*constructor),
{PropertyAttribute::Configurable, PropertyAttribute::Writable})));
return true;
}
if (ShouldIgnorePropertyDefinition(cx, key, id)) {
MOZ_ASSERT(desc.isNothing());
return true;
}
// Grab the JSClass. We require all Xrayable classes to have a ClassSpec.
const JSClass* clasp = JS::GetClass(target);
MOZ_ASSERT(clasp->specDefined());
// Indexed array properties are handled above, so we can just work with the
// class spec here.
return TryResolvePropertyFromSpecs(cx, id, holder,
clasp->specPrototypeFunctions(),
clasp->specPrototypeProperties(), desc);
}
bool JSXrayTraits::delete_(JSContext* cx, HandleObject wrapper, HandleId id,
ObjectOpResult& result) {
MOZ_ASSERT(js::IsObjectInContextCompartment(wrapper, cx));
RootedObject holder(cx, ensureHolder(cx, wrapper));
if (!holder) {
return false;
}
// If we're using Object Xrays, we allow callers to attempt to delete any
// property from the underlying object that they are able to resolve. Note
// that this deleting may fail if the property is non-configurable.
JSProtoKey key = getProtoKey(holder);
bool isObjectOrArrayInstance =
(key == JSProto_Object || key == JSProto_Array) && !isPrototype(holder);
if (isObjectOrArrayInstance) {
RootedObject wrapperGlobal(cx, JS::CurrentGlobalOrNull(cx));
RootedObject target(cx, getTargetObject(wrapper));
JSAutoRealm ar(cx, target);
JS_MarkCrossZoneId(cx, id);
Rooted<Maybe<PropertyDescriptor>> desc(cx);
if (!getOwnPropertyFromTargetIfSafe(cx, target, wrapper, wrapperGlobal, id,
&desc)) {
return false;
}
if (desc.isSome()) {
return JS_DeletePropertyById(cx, target, id, result);
}
}
return result.succeed();
}
bool JSXrayTraits::defineProperty(
JSContext* cx, HandleObject wrapper, HandleId id,
Handle<PropertyDescriptor> desc,
Handle<Maybe<PropertyDescriptor>> existingDesc,
Handle<JSObject*> existingHolder, ObjectOpResult& result, bool* defined) {
*defined = false;
RootedObject holder(cx, ensureHolder(cx, wrapper));
if (!holder) {
return false;
}
// Object and Array instances are special. For those cases, we forward
// property definitions to the underlying object if the following
// conditions are met:
// * The property being defined is a value-prop.
// * The property being defined is either a primitive or subsumed by the
// target.
// * As seen from the Xray, any existing property that we would overwrite
// is an |own| value-prop.
//
// To avoid confusion, we disallow expandos on Object and Array instances, and
// therefore raise an exception here if the above conditions aren't met.
JSProtoKey key = getProtoKey(holder);
bool isInstance = !isPrototype(holder);
bool isObjectOrArray = (key == JSProto_Object || key == JSProto_Array);
if (isObjectOrArray && isInstance) {
RootedObject target(cx, getTargetObject(wrapper));
if (desc.isAccessorDescriptor()) {
JS_ReportErrorASCII(cx,
"Not allowed to define accessor property on [Object] "
"or [Array] XrayWrapper");
return false;
}
if (desc.value().isObject() &&
!AccessCheck::subsumes(target,
js::UncheckedUnwrap(&desc.value().toObject()))) {
JS_ReportErrorASCII(cx,
"Not allowed to define cross-origin object as "
"property on [Object] or [Array] XrayWrapper");
return false;
}
if (existingDesc.isSome()) {
if (existingDesc->isAccessorDescriptor()) {
JS_ReportErrorASCII(cx,
"Not allowed to overwrite accessor property on "
"[Object] or [Array] XrayWrapper");
return false;
}
if (existingHolder != wrapper) {
JS_ReportErrorASCII(cx,
"Not allowed to shadow non-own Xray-resolved "
"property on [Object] or [Array] XrayWrapper");
return false;
}
}
Rooted<PropertyDescriptor> wrappedDesc(cx, desc);
JSAutoRealm ar(cx, target);
JS_MarkCrossZoneId(cx, id);
if (!JS_WrapPropertyDescriptor(cx, &wrappedDesc) ||
!JS_DefinePropertyById(cx, target, id, wrappedDesc, result)) {
return false;
}
*defined = true;
return true;
}
// For WebExtensions content scripts, we forward the definition of indexed
// properties. By validating that the key and value are both numbers, we can
// avoid doing any wrapping.
if (isInstance && IsTypedArrayKey(key) &&
CompartmentPrivate::Get(JS::CurrentGlobalOrNull(cx))
->isWebExtensionContentScript &&
desc.isDataDescriptor() &&
(desc.value().isNumber() || desc.value().isUndefined()) &&
IsArrayIndex(GetArrayIndexFromId(id))) {
RootedObject target(cx, getTargetObject(wrapper));
JSAutoRealm ar(cx, target);
JS_MarkCrossZoneId(cx, id);
if (!JS_DefinePropertyById(cx, target, id, desc, result)) {
return false;
}
*defined = true;
return true;
}
return true;
}
static bool MaybeAppend(jsid id, unsigned flags, MutableHandleIdVector props) {
MOZ_ASSERT(!(flags & JSITER_SYMBOLSONLY));
if (!(flags & JSITER_SYMBOLS) && id.isSymbol()) {
return true;
}
return props.append(id);
}
// Append the names from the given function and property specs to props.
static bool AppendNamesFromFunctionAndPropertySpecs(
JSContext* cx, JSProtoKey key, const JSFunctionSpec* fs,
const JSPropertySpec* ps, unsigned flags, MutableHandleIdVector props) {
// Convert the method and property names to jsids and pass them to the caller.
for (; fs && fs->name; ++fs) {
jsid id;
if (!PropertySpecNameToPermanentId(cx, fs->name, &id)) {
return false;
}
if (!js::ShouldIgnorePropertyDefinition(cx, key, id)) {
if (!MaybeAppend(id, flags, props)) {
return false;
}
}
}
for (; ps && ps->name; ++ps) {
jsid id;
if (!PropertySpecNameToPermanentId(cx, ps->name, &id)) {
return false;
}
if (!js::ShouldIgnorePropertyDefinition(cx, key, id)) {
if (!MaybeAppend(id, flags, props)) {
return false;
}
}
}
return true;
}
bool JSXrayTraits::enumerateNames(JSContext* cx, HandleObject wrapper,
unsigned flags, MutableHandleIdVector props) {
MOZ_ASSERT(js::IsObjectInContextCompartment(wrapper, cx));
RootedObject target(cx, getTargetObject(wrapper));
RootedObject holder(cx, ensureHolder(cx, wrapper));
if (!holder) {
return false;
}
JSProtoKey key = getProtoKey(holder);
if (!isPrototype(holder)) {
// For Object and Array instances, we expose some properties from the
// underlying object, but only after filtering them carefully.
if (key == JSProto_Object || key == JSProto_Array) {
MOZ_ASSERT(props.empty());
RootedObject wrapperGlobal(cx, JS::CurrentGlobalOrNull(cx));
{
JSAutoRealm ar(cx, target);
RootedIdVector targetProps(cx);
if (!js::GetPropertyKeys(cx, target, flags | JSITER_OWNONLY,
&targetProps)) {
return false;
}
// Loop over the properties, and only pass along the ones that
// we determine to be safe.
if (!props.reserve(targetProps.length())) {
return false;
}
for (size_t i = 0; i < targetProps.length(); ++i) {
Rooted<Maybe<PropertyDescriptor>> desc(cx);
RootedId id(cx, targetProps[i]);
if (!getOwnPropertyFromTargetIfSafe(cx, target, wrapper,
wrapperGlobal, id, &desc)) {
return false;
}
if (desc.isSome()) {
props.infallibleAppend(id);
}
}
}
for (size_t i = 0; i < props.length(); ++i) {
JS_MarkCrossZoneId(cx, props[i]);
}
return true;
}
if (IsTypedArrayKey(key)) {
size_t length = JS_GetTypedArrayLength(target);
// TypedArrays enumerate every indexed property in range, but
// |length| is a getter that lives on the proto, like it should be.
// Fail early if the typed array is enormous, because this will be very
// slow and will likely report OOM. This also means we don't need to
// handle indices greater than PropertyKey::IntMax in the loop below.
static_assert(PropertyKey::IntMax >= INT32_MAX);
if (length > INT32_MAX) {
JS_ReportOutOfMemory(cx);
return false;
}
if (!props.reserve(length)) {
return false;
}
for (int32_t i = 0; i < int32_t(length); ++i) {
props.infallibleAppend(PropertyKey::Int(i));
}
} else if (key == JSProto_Function) {
if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_LENGTH))) {
return false;
}
if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_NAME))) {
return false;
}
// Handle the .prototype property and static properties on standard
// constructors.
JSProtoKey standardConstructor = constructorFor(holder);
if (standardConstructor != JSProto_Null) {
if (ShouldResolvePrototypeProperty(standardConstructor)) {
if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_PROTOTYPE))) {
return false;
}
}
if (ShouldResolveStaticProperties(standardConstructor)) {
const JSClass* clasp = js::ProtoKeyToClass(standardConstructor);
MOZ_ASSERT(clasp->specDefined());
if (!AppendNamesFromFunctionAndPropertySpecs(
cx, key, clasp->specConstructorFunctions(),
clasp->specConstructorProperties(), flags, props)) {
return false;
}
}
}
} else if (IsErrorObjectKey(key)) {
if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_FILENAME)) ||
!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_LINENUMBER)) ||
!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_COLUMNNUMBER)) ||
!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_STACK)) ||
!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_MESSAGE))) {
return false;
}
} else if (key == JSProto_RegExp) {
if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_LASTINDEX))) {
return false;
}
} else if (key == JSProto_BoundFunction) {
if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_LENGTH)) ||
!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_NAME))) {
return false;
}
}
// The rest of this function applies only to prototypes.
return true;
}
// Add the 'constructor' property.
if (!props.append(GetJSIDByIndex(cx, XPCJSContext::IDX_CONSTRUCTOR))) {
return false;
}
// Grab the JSClass. We require all Xrayable classes to have a ClassSpec.
const JSClass* clasp = JS::GetClass(target);
MOZ_ASSERT(clasp->specDefined());
return AppendNamesFromFunctionAndPropertySpecs(
cx, key, clasp->specPrototypeFunctions(),
clasp->specPrototypeProperties(), flags, props);
}
bool JSXrayTraits::construct(JSContext* cx, HandleObject wrapper,
const JS::CallArgs& args,
const js::Wrapper& baseInstance) {
JSXrayTraits& self = JSXrayTraits::singleton;
JS::RootedObject holder(cx, self.ensureHolder(cx, wrapper));
if (!holder) {
return false;
}
const JSProtoKey key = xpc::JSXrayTraits::getProtoKey(holder);
if (key == JSProto_Function) {
JSProtoKey standardConstructor = constructorFor(holder);
if (standardConstructor == JSProto_Null) {
return baseInstance.construct(cx, wrapper, args);
}
const JSClass* clasp = js::ProtoKeyToClass(standardConstructor);
MOZ_ASSERT(clasp);
if (!(clasp->flags & JSCLASS_HAS_XRAYED_CONSTRUCTOR)) {
return baseInstance.construct(cx, wrapper, args);
}
// If the JSCLASS_HAS_XRAYED_CONSTRUCTOR flag is set on the Class,
// we don't use the constructor at hand. Instead, we retrieve the
// equivalent standard constructor in the xray compartment and run
// it in that compartment. The newTarget isn't unwrapped, and the
// constructor has to be able to detect and handle this situation.
// See the comments in js/public/Class.h and PromiseConstructor for
// details and an example.
RootedObject ctor(cx);
if (!JS_GetClassObject(cx, standardConstructor, &ctor)) {
return false;
}
RootedValue ctorVal(cx, ObjectValue(*ctor));
HandleValueArray vals(args);
RootedObject result(cx);
if (!JS::Construct(cx, ctorVal, wrapper, vals, &result)) {
return false;
}
AssertSameCompartment(cx, result);
args.rval().setObject(*result);
return true;
}
if (key == JSProto_BoundFunction) {
return baseInstance.construct(cx, wrapper, args);
}
JS::RootedValue v(cx, JS::ObjectValue(*wrapper));
js::ReportIsNotFunction(cx, v);
return false;
}
JSObject* JSXrayTraits::createHolder(JSContext* cx, JSObject* wrapper) {
RootedObject target(cx, getTargetObject(wrapper));
RootedObject holder(cx,
JS_NewObjectWithGivenProto(cx, &HolderClass, nullptr));
if (!holder) {
return nullptr;
}
// Compute information about the target.
bool isPrototype = false;
JSProtoKey key = IdentifyStandardInstance(target);
if (key == JSProto_Null) {
isPrototype = true;
key = IdentifyStandardPrototype(target);
}
MOZ_ASSERT(key != JSProto_Null);
// Special case: pretend Arguments objects are arrays for Xrays.
//
// Arguments objects are strange beasts - they inherit Object.prototype,
// and implement iteration by defining an |own| property for
// Symbol.iterator. Since this value is callable, Array/Object Xrays will
// filter it out, causing the Xray view to be non-iterable, which in turn
// breaks consumers.
//
// We can't trust the iterator value from the content compartment,
// but the generic one on Array.prototype works well enough. So we force
// the Xray view of Arguments objects to inherit Array.prototype, which
// in turn allows iteration via the inherited
// Array.prototype[Symbol.iterator]. This doesn't emulate any of the weird
// semantics of Arguments iterators, but is probably good enough.
//
// Note that there are various Xray traps that do other special behavior for
// JSProto_Array, but they also provide that special behavior for
// JSProto_Object, and since Arguments would otherwise get JSProto_Object,
// this does not cause any behavior change at those sites.
if (key == JSProto_Object && js::IsArgumentsObject(target)) {
key = JSProto_Array;
}
// Store it on the holder.
RootedValue v(cx);
v.setNumber(static_cast<uint32_t>(key));
JS::SetReservedSlot(holder, SLOT_PROTOKEY, v);
v.setBoolean(isPrototype);
JS::SetReservedSlot(holder, SLOT_ISPROTOTYPE, v);
// If this is a function, also compute whether it serves as a constructor
// for a standard class.
if (key == JSProto_Function) {
v.setNumber(static_cast<uint32_t>(IdentifyStandardConstructor(target)));
JS::SetReservedSlot(holder, SLOT_CONSTRUCTOR_FOR, v);
}
return holder;
}
DOMXrayTraits DOMXrayTraits::singleton;
JSXrayTraits JSXrayTraits::singleton;
OpaqueXrayTraits OpaqueXrayTraits::singleton;
XrayTraits* GetXrayTraits(JSObject* obj) {
switch (GetXrayType(obj)) {
case XrayForDOMObject:
return &DOMXrayTraits::singleton;
case XrayForJSObject:
return &JSXrayTraits::singleton;
case XrayForOpaqueObject:
return &OpaqueXrayTraits::singleton;
default:
return nullptr;
}
}
/*
* Xray expando handling.
*
* We hang expandos for Xray wrappers off a reserved slot on the target object
* so that same-origin compartments can share expandos for a given object. We
* have a linked list of expando objects, one per origin. The properties on
* these objects are generally wrappers pointing back to the compartment that
* applied them.
*
* The expando objects should _never_ be exposed to script. The fact that they
* live in the target compartment is a detail of the implementation, and does
* not imply that code in the target compartment should be allowed to inspect
* them. They are private to the origin that placed them.
*/
// Certain compartments do not share expandos with other compartments. Xrays in
// these compartments cache expandos on the wrapper's holder, as there is only
// one such wrapper which can create or access the expando. This allows for
// faster access to the expando, including through JIT inline caches.
static inline bool CompartmentHasExclusiveExpandos(JSObject* obj) {
JS::Compartment* comp = JS::GetCompartment(obj);
CompartmentPrivate* priv = CompartmentPrivate::Get(comp);
return priv && priv->hasExclusiveExpandos;
}
static inline JSObject* GetCachedXrayExpando(JSObject* wrapper);
static inline void SetCachedXrayExpando(JSObject* holder,
JSObject* expandoWrapper);
static nsIPrincipal* WrapperPrincipal(JSObject* obj) {
// Use the principal stored in CompartmentOriginInfo. That works because
// consumers are only interested in the origin-ignoring-document.domain.
// See expandoObjectMatchesConsumer.
MOZ_ASSERT(IsXrayWrapper(obj));
JS::Compartment* comp = JS::GetCompartment(obj);
CompartmentPrivate* priv = CompartmentPrivate::Get(comp);
return priv->originInfo.GetPrincipalIgnoringDocumentDomain();
}
static nsIPrincipal* GetExpandoObjectPrincipal(JSObject* expandoObject) {
Value v = JS::GetReservedSlot(expandoObject, JSSLOT_EXPANDO_ORIGIN);
return static_cast<nsIPrincipal*>(v.toPrivate());
}
static void ExpandoObjectFinalize(JS::GCContext* gcx, JSObject* obj) {
// Release the principal.
nsIPrincipal* principal = GetExpandoObjectPrincipal(obj);
NS_RELEASE(principal);
}
const JSClassOps XrayExpandoObjectClassOps = {
nullptr, // addProperty
nullptr, // delProperty
nullptr, // enumerate
nullptr, // newEnumerate
nullptr, // resolve
nullptr, // mayResolve
ExpandoObjectFinalize, // finalize
nullptr, // call
nullptr, // construct
nullptr, // trace
};
bool XrayTraits::expandoObjectMatchesConsumer(JSContext* cx,
HandleObject expandoObject,
nsIPrincipal* consumerOrigin) {
MOZ_ASSERT(js::IsObjectInContextCompartment(expandoObject, cx));
// First, compare the principals.
nsIPrincipal* o = GetExpandoObjectPrincipal(expandoObject);
// Note that it's very important here to ignore document.domain. We
// pull the principal for the expando object off of the first consumer
// for a given origin, and freely share the expandos amongst multiple
// same-origin consumers afterwards. However, this means that we have
// no way to know whether _all_ consumers have opted in to collaboration
// by explicitly setting document.domain. So we just mandate that expando
// sharing is unaffected by it.
if (!consumerOrigin->Equals(o)) {
return false;
}
// Certain globals exclusively own the associated expandos, in which case
// the caller should have used the cached expando on the wrapper instead.
JSObject* owner = JS::GetReservedSlot(expandoObject,
JSSLOT_EXPANDO_EXCLUSIVE_WRAPPER_HOLDER)
.toObjectOrNull();
return owner == nullptr;
}
bool XrayTraits::getExpandoObjectInternal(JSContext* cx, JSObject* expandoChain,
HandleObject exclusiveWrapper,
nsIPrincipal* origin,
MutableHandleObject expandoObject) {
MOZ_ASSERT(!JS_IsExceptionPending(cx));
expandoObject.set(nullptr);
// Use the cached expando if this wrapper has exclusive access to it.
if (exclusiveWrapper) {
JSObject* expandoWrapper = GetCachedXrayExpando(exclusiveWrapper);
expandoObject.set(expandoWrapper ? UncheckedUnwrap(expandoWrapper)
: nullptr);
#ifdef DEBUG
// Make sure the expando we found is on the target's chain. While we
// don't use this chain to look up expandos for the wrapper,
// the expando still needs to be on the chain to keep the wrapper and
// expando alive.
if (expandoObject) {
JSObject* head = expandoChain;
while (head && head != expandoObject) {
head = JS::GetReservedSlot(head, JSSLOT_EXPANDO_NEXT).toObjectOrNull();
}
MOZ_ASSERT(head == expandoObject);
}
#endif
return true;
}
// The expando object lives in the compartment of the target, so all our
// work needs to happen there.
RootedObject head(cx, expandoChain);
JSAutoRealm ar(cx, head);
// Iterate through the chain, looking for a same-origin object.
while (head) {
if (expandoObjectMatchesConsumer(cx, head, origin)) {
expandoObject.set(head);
return true;
}
head = JS::GetReservedSlot(head, JSSLOT_EXPANDO_NEXT).toObjectOrNull();
}
// Not found.
return true;
}
bool XrayTraits::getExpandoObject(JSContext* cx, HandleObject target,
HandleObject consumer,
MutableHandleObject expandoObject) {
// Return early if no expando object has ever been attached, which is
// usually the case.
JSObject* chain = getExpandoChain(target);
if (!chain) {
return true;
}
bool isExclusive = CompartmentHasExclusiveExpandos(consumer);
return getExpandoObjectInternal(cx, chain, isExclusive ? consumer : nullptr,
WrapperPrincipal(consumer), expandoObject);
}
// Wrappers which have exclusive access to the expando on their target object
// need to be kept alive as long as the target object exists. This is done by
// keeping the expando in the expando chain on the target (even though it will
// not be used while looking up the expando for the wrapper), and keeping a
// strong reference from that expando to the wrapper itself, via the
// JSSLOT_EXPANDO_EXCLUSIVE_WRAPPER_HOLDER reserved slot. This slot does not
// point to the wrapper itself, because it is a cross compartment edge and we
// can't create a wrapper for a wrapper. Instead, the slot points to an
// instance of the holder class below in the wrapper's compartment, and the
// wrapper is held via this holder object's reserved slot.
static const JSClass gWrapperHolderClass = {"XrayExpandoWrapperHolder",
JSCLASS_HAS_RESERVED_SLOTS(1)};
static const size_t JSSLOT_WRAPPER_HOLDER_CONTENTS = 0;
JSObject* XrayTraits::attachExpandoObject(JSContext* cx, HandleObject target,
HandleObject exclusiveWrapper,
HandleObject exclusiveWrapperGlobal,
nsIPrincipal* origin) {
// Make sure the compartments are sane.
MOZ_ASSERT(js::IsObjectInContextCompartment(target, cx));
if (exclusiveWrapper) {
MOZ_ASSERT(!js::IsObjectInContextCompartment(exclusiveWrapper, cx));
MOZ_ASSERT(JS_IsGlobalObject(exclusiveWrapperGlobal));
js::AssertSameCompartment(exclusiveWrapper, exclusiveWrapperGlobal);
}
// No duplicates allowed.
#ifdef DEBUG
{
JSObject* chain = getExpandoChain(target);
if (chain) {
RootedObject existingExpandoObject(cx);
if (getExpandoObjectInternal(cx, chain, exclusiveWrapper, origin,
&existingExpandoObject)) {
MOZ_ASSERT(!existingExpandoObject);
} else {
JS_ClearPendingException(cx);
}
}
}
#endif
// Create the expando object.
const JSClass* expandoClass = getExpandoClass(cx, target);
MOZ_ASSERT(!strcmp(expandoClass->name, "XrayExpandoObject"));
RootedObject expandoObject(
cx, JS_NewObjectWithGivenProto(cx, expandoClass, nullptr));
if (!expandoObject) {
return nullptr;
}
// AddRef and store the principal.
NS_ADDREF(origin);
JS_SetReservedSlot(expandoObject, JSSLOT_EXPANDO_ORIGIN,
JS::PrivateValue(origin));
// Note the exclusive wrapper, if there is one.
RootedObject wrapperHolder(cx);
if (exclusiveWrapper) {
JSAutoRealm ar(cx, exclusiveWrapperGlobal);
wrapperHolder =
JS_NewObjectWithGivenProto(cx, &gWrapperHolderClass, nullptr);
if (!wrapperHolder) {
return nullptr;
}
JS_SetReservedSlot(wrapperHolder, JSSLOT_WRAPPER_HOLDER_CONTENTS,
ObjectValue(*exclusiveWrapper));
}
if (!JS_WrapObject(cx, &wrapperHolder)) {
return nullptr;
}
JS_SetReservedSlot(expandoObject, JSSLOT_EXPANDO_EXCLUSIVE_WRAPPER_HOLDER,
ObjectOrNullValue(wrapperHolder));
// Store it on the exclusive wrapper, if there is one.
if (exclusiveWrapper) {
RootedObject cachedExpandoObject(cx, expandoObject);
JSAutoRealm ar(cx, exclusiveWrapperGlobal);
if (!JS_WrapObject(cx, &cachedExpandoObject)) {
return nullptr;
}
JSObject* holder = ensureHolder(cx, exclusiveWrapper);
if (!holder) {
return nullptr;
}
SetCachedXrayExpando(holder, cachedExpandoObject);
}
// If this is our first expando object, take the opportunity to preserve
// the wrapper. This keeps our expandos alive even if the Xray wrapper gets
// collected.
RootedObject chain(cx, getExpandoChain(target));
if (!chain) {
preserveWrapper(target);
}
// Insert it at the front of the chain.
JS_SetReservedSlot(expandoObject, JSSLOT_EXPANDO_NEXT,
ObjectOrNullValue(chain));
setExpandoChain(cx, target, expandoObject);
return expandoObject;
}
JSObject* XrayTraits::ensureExpandoObject(JSContext* cx, HandleObject wrapper,
HandleObject target) {
MOZ_ASSERT(js::IsObjectInContextCompartment(wrapper, cx));
RootedObject wrapperGlobal(cx, JS::CurrentGlobalOrNull(cx));
// Expando objects live in the target compartment.
JSAutoRealm ar(cx, target);
RootedObject expandoObject(cx);
if (!getExpandoObject(cx, target, wrapper, &expandoObject)) {
return nullptr;
}
if (!expandoObject) {
bool isExclusive = CompartmentHasExclusiveExpandos(wrapper);
expandoObject =
attachExpandoObject(cx, target, isExclusive ? wrapper : nullptr,
wrapperGlobal, WrapperPrincipal(wrapper));
}
return expandoObject;
}
bool XrayTraits::cloneExpandoChain(JSContext* cx, HandleObject dst,
HandleObject srcChain) {
MOZ_ASSERT(js::IsObjectInContextCompartment(dst, cx));
MOZ_ASSERT(getExpandoChain(dst) == nullptr);
RootedObject oldHead(cx, srcChain);
while (oldHead) {
// If movingIntoXrayCompartment is true, then our new reflector is in a
// compartment that used to have an Xray-with-expandos to the old reflector
// and we should copy the expandos to the new reflector directly.
bool movingIntoXrayCompartment;
// exclusiveWrapper is only used if movingIntoXrayCompartment ends up true.
RootedObject exclusiveWrapper(cx);
RootedObject exclusiveWrapperGlobal(cx);
RootedObject wrapperHolder(
cx,
JS::GetReservedSlot(oldHead, JSSLOT_EXPANDO_EXCLUSIVE_WRAPPER_HOLDER)
.toObjectOrNull());
if (wrapperHolder) {
RootedObject unwrappedHolder(cx, UncheckedUnwrap(wrapperHolder));
// unwrappedHolder is the compartment of the relevant Xray, so check
// whether that matches the compartment of cx (which matches the
// compartment of dst).
movingIntoXrayCompartment =
js::IsObjectInContextCompartment(unwrappedHolder, cx);
if (!movingIntoXrayCompartment) {
// The global containing this wrapper holder has an xray for |src|
// with expandos. Create an xray in the global for |dst| which
// will be associated with a clone of |src|'s expando object.
JSAutoRealm ar(cx, unwrappedHolder);
exclusiveWrapper = dst;
if (!JS_WrapObject(cx, &exclusiveWrapper)) {
return false;
}
exclusiveWrapperGlobal = JS::CurrentGlobalOrNull(cx);
}
} else {
JSAutoRealm ar(cx, oldHead);
movingIntoXrayCompartment =
expandoObjectMatchesConsumer(cx, oldHead, GetObjectPrincipal(dst));
}
if (movingIntoXrayCompartment) {
// Just copy properties directly onto dst.
if (!JS_CopyOwnPropertiesAndPrivateFields(cx, dst, oldHead)) {
return false;
}
} else {
// Create a new expando object in the compartment of dst to replace
// oldHead.
RootedObject newHead(
cx,
attachExpandoObject(cx, dst, exclusiveWrapper, exclusiveWrapperGlobal,
GetExpandoObjectPrincipal(oldHead)));
if (!JS_CopyOwnPropertiesAndPrivateFields(cx, newHead, oldHead)) {
return false;
}
}
oldHead =
JS::GetReservedSlot(oldHead, JSSLOT_EXPANDO_NEXT).toObjectOrNull();
}
return true;
}
void ClearXrayExpandoSlots(JSObject* target, size_t slotIndex) {
if (!NS_IsMainThread()) {
// No Xrays
return;
}
MOZ_ASSERT(slotIndex != JSSLOT_EXPANDO_NEXT);
MOZ_ASSERT(slotIndex != JSSLOT_EXPANDO_EXCLUSIVE_WRAPPER_HOLDER);
MOZ_ASSERT(GetXrayTraits(target) == &DOMXrayTraits::singleton);
RootingContext* rootingCx = RootingCx();
RootedObject rootedTarget(rootingCx, target);
RootedObject head(rootingCx,
DOMXrayTraits::singleton.getExpandoChain(rootedTarget));
while (head) {
MOZ_ASSERT(JSCLASS_RESERVED_SLOTS(JS::GetClass(head)) > slotIndex);
JS::SetReservedSlot(head, slotIndex, UndefinedValue());
head = JS::GetReservedSlot(head, JSSLOT_EXPANDO_NEXT).toObjectOrNull();
}
}
JSObject* EnsureXrayExpandoObject(JSContext* cx, JS::HandleObject wrapper) {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(GetXrayTraits(wrapper) == &DOMXrayTraits::singleton);
MOZ_ASSERT(IsXrayWrapper(wrapper));
RootedObject target(cx, DOMXrayTraits::getTargetObject(wrapper));
return DOMXrayTraits::singleton.ensureExpandoObject(cx, wrapper, target);
}
const JSClass* XrayTraits::getExpandoClass(JSContext* cx,
HandleObject target) const {
return &DefaultXrayExpandoObjectClass;
}
static const size_t JSSLOT_XRAY_HOLDER = 0;
/* static */
JSObject* XrayTraits::getHolder(JSObject* wrapper) {
MOZ_ASSERT(WrapperFactory::IsXrayWrapper(wrapper));
JS::Value v = js::GetProxyReservedSlot(wrapper, JSSLOT_XRAY_HOLDER);
return v.isObject() ? &v.toObject() : nullptr;
}
JSObject* XrayTraits::ensureHolder(JSContext* cx, HandleObject wrapper) {
RootedObject holder(cx, getHolder(wrapper));
if (holder) {
return holder;
}
holder = createHolder(cx, wrapper); // virtual trap.
if (holder) {
js::SetProxyReservedSlot(wrapper, JSSLOT_XRAY_HOLDER, ObjectValue(*holder));
}
return holder;
}
static inline JSObject* GetCachedXrayExpando(JSObject* wrapper) {
JSObject* holder = XrayTraits::getHolder(wrapper);
if (!holder) {
return nullptr;
}
Value v = JS::GetReservedSlot(holder, XrayTraits::HOLDER_SLOT_EXPANDO);
return v.isObject() ? &v.toObject() : nullptr;
}
static inline void SetCachedXrayExpando(JSObject* holder,
JSObject* expandoWrapper) {
MOZ_ASSERT(JS::GetCompartment(holder) == JS::GetCompartment(expandoWrapper));
JS_SetReservedSlot(holder, XrayTraits::HOLDER_SLOT_EXPANDO,
ObjectValue(*expandoWrapper));
}
static nsGlobalWindowInner* AsWindow(JSContext* cx, JSObject* wrapper) {
// We want to use our target object here, since we don't want to be
// doing a security check while unwrapping.
JSObject* target = XrayTraits::getTargetObject(wrapper);
return WindowOrNull(target);
}
static bool IsWindow(JSContext* cx, JSObject* wrapper) {
return !!AsWindow(cx, wrapper);
}
static bool wrappedJSObject_getter(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
if (!args.thisv().isObject()) {
JS_ReportErrorASCII(cx, "This value not an object");
return false;
}
RootedObject wrapper(cx, &args.thisv().toObject());
if (!IsWrapper(wrapper) || !WrapperFactory::IsXrayWrapper(wrapper) ||
!WrapperFactory::AllowWaiver(wrapper)) {
JS_ReportErrorASCII(cx, "Unexpected object");
return false;
}
args.rval().setObject(*wrapper);
return WrapperFactory::WaiveXrayAndWrap(cx, args.rval());
}
bool XrayTraits::resolveOwnProperty(
JSContext* cx, HandleObject wrapper, HandleObject target,
HandleObject holder, HandleId id,
MutableHandle<Maybe<PropertyDescriptor>> desc) {
desc.reset();
RootedObject expando(cx);
if (!getExpandoObject(cx, target, wrapper, &expando)) {
return false;
}
// Check for expando properties first. Note that the expando object lives
// in the target compartment.
if (expando) {
JSAutoRealm ar(cx, expando);
JS_MarkCrossZoneId(cx, id);
if (!JS_GetOwnPropertyDescriptorById(cx, expando, id, desc)) {
return false;
}
}
// Next, check for ES builtins.
if (!desc.isSome() && JS_IsGlobalObject(target)) {
JSProtoKey key = JS_IdToProtoKey(cx, id);
JSAutoRealm ar(cx, target);
if (key != JSProto_Null) {
MOZ_ASSERT(key < JSProto_LIMIT);
RootedObject constructor(cx);
if (!JS_GetClassObject(cx, key, &constructor)) {
return false;
}
MOZ_ASSERT(constructor);
desc.set(Some(PropertyDescriptor::Data(
ObjectValue(*constructor),
{PropertyAttribute::Configurable, PropertyAttribute::Writable})));
} else if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_EVAL)) {
RootedObject eval(cx);
if (!js::GetRealmOriginalEval(cx, &eval)) {
return false;
}
desc.set(Some(PropertyDescriptor::Data(
ObjectValue(*eval),
{PropertyAttribute::Configurable, PropertyAttribute::Writable})));
} else if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_INFINITY)) {
desc.set(Some(PropertyDescriptor::Data(
DoubleValue(PositiveInfinity<double>()), {})));
} else if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_NAN)) {
desc.set(Some(PropertyDescriptor::Data(NaNValue(), {})));
}
}
if (desc.isSome()) {
return JS_WrapPropertyDescriptor(cx, desc);
}
// Handle .wrappedJSObject for subsuming callers. This should move once we
// sort out own-ness for the holder.
if (id == GetJSIDByIndex(cx, XPCJSContext::IDX_WRAPPED_JSOBJECT) &&
WrapperFactory::AllowWaiver(wrapper)) {
bool found = false;
if (!JS_AlreadyHasOwnPropertyById(cx, holder, id, &found)) {
return false;
}
if (!found && !JS_DefinePropertyById(cx, holder, id, wrappedJSObject_getter,
nullptr, JSPROP_ENUMERATE)) {
return false;
}
return JS_GetOwnPropertyDescriptorById(cx, holder, id, desc);
}
return true;
}
bool DOMXrayTraits::resolveOwnProperty(
JSContext* cx, HandleObject wrapper, HandleObject target,
HandleObject holder, HandleId id,
MutableHandle<Maybe<PropertyDescriptor>> desc) {
// Call the common code.
bool ok =
XrayTraits::resolveOwnProperty(cx, wrapper, target, holder, id, desc);
if (!ok || desc.isSome()) {
return ok;
}
// Check for indexed access on a window.
uint32_t index = GetArrayIndexFromId(id);
if (IsArrayIndex(index)) {
nsGlobalWindowInner* win = AsWindow(cx, wrapper);
// Note: As() unwraps outer windows to get to the inner window.
if (win) {
Nullable<WindowProxyHolder> subframe = win->IndexedGetter(index);
if (!subframe.IsNull()) {
Rooted<Value> value(cx);
if (MOZ_UNLIKELY(!WrapObject(cx, subframe.Value(), &value))) {
// It's gone?
return xpc::Throw(cx, NS_ERROR_FAILURE);
}
desc.set(Some(PropertyDescriptor::Data(
value,
{PropertyAttribute::Configurable, PropertyAttribute::Enumerable})));
return JS_WrapPropertyDescriptor(cx, desc);
}
}
}
if (!JS_GetOwnPropertyDescriptorById(cx, holder, id, desc)) {
return false;
}
if (desc.isSome()) {
return true;
}
bool cacheOnHolder;
if (!XrayResolveOwnProperty(cx, wrapper, target, id, desc, cacheOnHolder)) {
return false;
}
if (desc.isNothing() || !cacheOnHolder) {
return true;
}
Rooted<PropertyDescriptor> defineDesc(cx, *desc);
return JS_DefinePropertyById(cx, holder, id, defineDesc) &&
JS_GetOwnPropertyDescriptorById(cx, holder, id, desc);
}
bool DOMXrayTraits::delete_(JSContext* cx, JS::HandleObject wrapper,
JS::HandleId id, JS::ObjectOpResult& result) {
RootedObject target(cx, getTargetObject(wrapper));
return XrayDeleteNamedProperty(cx, wrapper, target, id, result);
}
bool DOMXrayTraits::defineProperty(
JSContext* cx, HandleObject wrapper, HandleId id,
Handle<PropertyDescriptor> desc,
Handle<Maybe<PropertyDescriptor>> existingDesc,
Handle<JSObject*> existingHolder, JS::ObjectOpResult& result, bool* done) {
// Check for an indexed property on a Window. If that's happening, do
// nothing but set done to true so it won't get added as an expando.
if (IsWindow(cx, wrapper)) {
if (IsArrayIndex(GetArrayIndexFromId(id))) {
*done = true;
return result.succeed();
}
}
JS::Rooted<JSObject*> obj(cx, getTargetObject(wrapper));
return XrayDefineProperty(cx, wrapper, obj, id, desc, result, done);
}
bool DOMXrayTraits::enumerateNames(JSContext* cx, HandleObject wrapper,
unsigned flags,
MutableHandleIdVector props) {
// Put the indexed properties for a window first.
nsGlobalWindowInner* win = AsWindow(cx, wrapper);
if (win) {
uint32_t length = win->Length();
if (!props.reserve(props.length() + length)) {
return false;
}
JS::RootedId indexId(cx);
for (uint32_t i = 0; i < length; ++i) {
if (!JS_IndexToId(cx, i, &indexId)) {
return false;
}
props.infallibleAppend(indexId);
}
}
JS::Rooted<JSObject*> obj(cx, getTargetObject(wrapper));
if (JS_IsGlobalObject(obj)) {
// We could do this in a shared enumerateNames with JSXrayTraits, but we
// don't really have globals we expose via those.
JSAutoRealm ar(cx, obj);
if (!JS_NewEnumerateStandardClassesIncludingResolved(
cx, obj, props, !(flags & JSITER_HIDDEN))) {
return false;
}
}
return XrayOwnPropertyKeys(cx, wrapper, obj, flags, props);
}
bool DOMXrayTraits::call(JSContext* cx, HandleObject wrapper,
const JS::CallArgs& args,
const js::Wrapper& baseInstance) {
RootedObject obj(cx, getTargetObject(wrapper));
// What we have is either a WebIDL interface object, a WebIDL prototype
// object, or a WebIDL instance object. WebIDL interface objects we want to
// invoke on the xray compartment. WebIDL prototype objects never have a
// clasp->call. WebIDL instance objects either don't have a clasp->call or are
// using "legacycaller". At this time for all the legacycaller users it makes
// more sense to invoke on the xray compartment, so we just go ahead and do
// that for everything.
if (IsDOMConstructor(obj)) {
const JSNativeHolder* holder = NativeHolderFromObject(obj);
return holder->mNative(cx, args.length(), args.base());
}
if (js::IsProxy(obj)) {
if (JS::IsCallable(obj)) {
// Passing obj here, but it doesn't really matter because legacycaller
// uses args.callee() anyway.
return GetProxyHandler(obj)->call(cx, obj, args);
}
} else {
const JSClass* clasp = JS::GetClass(obj);
if (JSNative call = clasp->getCall()) {
// call it on the Xray compartment
return call(cx, args.length(), args.base());
}
}
RootedValue v(cx, ObjectValue(*wrapper));
js::ReportIsNotFunction(cx, v);
return false;
}
bool DOMXrayTraits::construct(JSContext* cx, HandleObject wrapper,
const JS::CallArgs& args,
const js::Wrapper& baseInstance) {
RootedObject obj(cx, getTargetObject(wrapper));
// See comments in DOMXrayTraits::call() explaining what's going on here.
if (IsDOMConstructor(obj)) {
const JSNativeHolder* holder = NativeHolderFromObject(obj);
if (!holder->mNative(cx, args.length(), args.base())) {
return false;
}
} else {
const JSClass* clasp = JS::GetClass(obj);
if (clasp->flags & JSCLASS_IS_DOMIFACEANDPROTOJSCLASS) {
MOZ_ASSERT(!clasp->getConstruct());
RootedValue v(cx, ObjectValue(*wrapper));
js::ReportIsNotFunction(cx, v);
return false;
}
if (!baseInstance.construct(cx, wrapper, args)) {
return false;
}
}
if (!args.rval().isObject() || !JS_WrapValue(cx, args.rval())) {
return false;
}
return true;
}
bool DOMXrayTraits::getPrototype(JSContext* cx, JS::HandleObject wrapper,
JS::HandleObject target,
JS::MutableHandleObject protop) {
return mozilla::dom::XrayGetNativeProto(cx, target, protop);
}
void DOMXrayTraits::preserveWrapper(JSObject* target) {
nsISupports* identity = mozilla::dom::UnwrapDOMObjectToISupports(target);
if (!identity) {
return;
}
nsWrapperCache* cache = nullptr;
CallQueryInterface(identity, &cache);
if (cache) {
cache->PreserveWrapper(identity);
}
}
JSObject* DOMXrayTraits::createHolder(JSContext* cx, JSObject* wrapper) {
return JS_NewObjectWithGivenProto(cx, &HolderClass, nullptr);
}
const JSClass* DOMXrayTraits::getExpandoClass(JSContext* cx,
HandleObject target) const {
return XrayGetExpandoClass(cx, target);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::preventExtensions(
JSContext* cx, HandleObject wrapper, ObjectOpResult& result) const {
// Xray wrappers are supposed to provide a clean view of the target
// reflector, hiding any modifications by script in the target scope. So
// even if that script freezes the reflector, we don't want to make that
// visible to the caller. DOM reflectors are always extensible by default,
// so we can just return failure here.
return result.failCantPreventExtensions();
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::isExtensible(JSContext* cx,
JS::Handle<JSObject*> wrapper,
bool* extensible) const {
// See above.
*extensible = true;
return true;
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::getOwnPropertyDescriptor(
JSContext* cx, HandleObject wrapper, HandleId id,
MutableHandle<Maybe<PropertyDescriptor>> desc) const {
assertEnteredPolicy(cx, wrapper, id,
BaseProxyHandler::GET | BaseProxyHandler::SET |
BaseProxyHandler::GET_PROPERTY_DESCRIPTOR);
RootedObject target(cx, Traits::getTargetObject(wrapper));
RootedObject holder(cx, Traits::singleton.ensureHolder(cx, wrapper));
if (!holder) {
return false;
}
return Traits::singleton.resolveOwnProperty(cx, wrapper, target, holder, id,
desc);
}
// Consider what happens when chrome does |xray.expando = xray.wrappedJSObject|.
//
// Since the expando comes from the target compartment, wrapping it back into
// the target compartment to define it on the expando object ends up stripping
// off the Xray waiver that gives |xray| and |xray.wrappedJSObject| different
// identities. This is generally the right thing to do when wrapping across
// compartments, but is incorrect in the special case of the Xray expando
// object. Manually re-apply Xrays if necessary.
//
// NB: In order to satisfy the invariants of WaiveXray, we need to pass
// in an object sans security wrapper, which means we need to strip off any
// potential same-compartment security wrapper that may have been applied
// to the content object. This is ok, because the the expando object is only
// ever accessed by code across the compartment boundary.
static bool RecreateLostWaivers(JSContext* cx, const PropertyDescriptor* orig,
MutableHandle<PropertyDescriptor> wrapped) {
// Compute whether the original objects were waived, and implicitly, whether
// they were objects at all.
bool valueWasWaived =
orig->hasValue() && orig->value().isObject() &&
WrapperFactory::HasWaiveXrayFlag(&orig->value().toObject());
bool getterWasWaived = orig->hasGetter() && orig->getter() &&
WrapperFactory::HasWaiveXrayFlag(orig->getter());
bool setterWasWaived = orig->hasSetter() && orig->setter() &&
WrapperFactory::HasWaiveXrayFlag(orig->setter());
// Recreate waivers. Note that for value, we need an extra UncheckedUnwrap
// to handle same-compartment security wrappers (see above). This should
// never happen for getters/setters.
RootedObject rewaived(cx);
if (valueWasWaived &&
!IsCrossCompartmentWrapper(&wrapped.value().toObject())) {
rewaived = &wrapped.value().toObject();
rewaived = WrapperFactory::WaiveXray(cx, UncheckedUnwrap(rewaived));
NS_ENSURE_TRUE(rewaived, false);
wrapped.value().set(ObjectValue(*rewaived));
}
if (getterWasWaived && !IsCrossCompartmentWrapper(wrapped.getter())) {
// We can't end up with WindowProxy or Location as getters.
MOZ_ASSERT(CheckedUnwrapStatic(wrapped.getter()));
rewaived = WrapperFactory::WaiveXray(cx, wrapped.getter());
NS_ENSURE_TRUE(rewaived, false);
wrapped.setGetter(rewaived);
}
if (setterWasWaived && !IsCrossCompartmentWrapper(wrapped.setter())) {
// We can't end up with WindowProxy or Location as setters.
MOZ_ASSERT(CheckedUnwrapStatic(wrapped.setter()));
rewaived = WrapperFactory::WaiveXray(cx, wrapped.setter());
NS_ENSURE_TRUE(rewaived, false);
wrapped.setSetter(rewaived);
}
return true;
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::defineProperty(JSContext* cx,
HandleObject wrapper,
HandleId id,
Handle<PropertyDescriptor> desc,
ObjectOpResult& result) const {
assertEnteredPolicy(cx, wrapper, id, BaseProxyHandler::SET);
Rooted<Maybe<PropertyDescriptor>> existingDesc(cx);
Rooted<JSObject*> existingHolder(cx);
if (!JS_GetPropertyDescriptorById(cx, wrapper, id, &existingDesc,
&existingHolder)) {
return false;
}
// Note that the check here is intended to differentiate between own and
// non-own properties, since the above lookup is not limited to own
// properties. At present, this may not always do the right thing because
// we often lie (sloppily) about where we found properties and set
// existingHolder to |wrapper|. Once we fully fix our Xray prototype
// semantics, this should work as intended.
if (existingDesc.isSome() && existingHolder == wrapper &&
!existingDesc->configurable()) {
// We have a non-configurable property. See if the caller is trying to
// re-configure it in any way other than making it non-writable.
if (existingDesc->isAccessorDescriptor() || desc.isAccessorDescriptor() ||
(desc.hasEnumerable() &&
existingDesc->enumerable() != desc.enumerable()) ||
(desc.hasWritable() && !existingDesc->writable() && desc.writable())) {
// We should technically report non-configurability in strict mode, but
return result.succeed();
}
if (!existingDesc->writable()) {
// Same as the above for non-writability.
return result.succeed();
}
}
bool done = false;
if (!Traits::singleton.defineProperty(cx, wrapper, id, desc, existingDesc,
existingHolder, result, &done)) {
return false;
}
if (done) {
return true;
}
// Grab the relevant expando object.
RootedObject target(cx, Traits::getTargetObject(wrapper));
RootedObject expandoObject(
cx, Traits::singleton.ensureExpandoObject(cx, wrapper, target));
if (!expandoObject) {
return false;
}
// We're placing an expando. The expando objects live in the target
// compartment, so we need to enter it.
JSAutoRealm ar(cx, target);
JS_MarkCrossZoneId(cx, id);
// Wrap the property descriptor for the target compartment.
Rooted<PropertyDescriptor> wrappedDesc(cx, desc);
if (!JS_WrapPropertyDescriptor(cx, &wrappedDesc)) {
return false;
}
// Fix up Xray waivers.
if (!RecreateLostWaivers(cx, desc.address(), &wrappedDesc)) {
return false;
}
return JS_DefinePropertyById(cx, expandoObject, id, wrappedDesc, result);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::ownPropertyKeys(
JSContext* cx, HandleObject wrapper, MutableHandleIdVector props) const {
assertEnteredPolicy(cx, wrapper, JS::PropertyKey::Void(),
BaseProxyHandler::ENUMERATE);
return getPropertyKeys(
cx, wrapper, JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS, props);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::delete_(JSContext* cx, HandleObject wrapper,
HandleId id,
ObjectOpResult& result) const {
assertEnteredPolicy(cx, wrapper, id, BaseProxyHandler::SET);
// Check the expando object.
RootedObject target(cx, Traits::getTargetObject(wrapper));
RootedObject expando(cx);
if (!Traits::singleton.getExpandoObject(cx, target, wrapper, &expando)) {
return false;
}
if (expando) {
JSAutoRealm ar(cx, expando);
JS_MarkCrossZoneId(cx, id);
bool hasProp;
if (!JS_HasPropertyById(cx, expando, id, &hasProp)) {
return false;
}
if (hasProp) {
return JS_DeletePropertyById(cx, expando, id, result);
}
}
return Traits::singleton.delete_(cx, wrapper, id, result);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::get(JSContext* cx, HandleObject wrapper,
HandleValue receiver, HandleId id,
MutableHandleValue vp) const {
// This is called by Proxy::get, but since we return true for hasPrototype()
// it's only called for properties that hasOwn() claims we have as own
// properties. Since we only need to worry about own properties, we can use
// getOwnPropertyDescriptor here.
Rooted<Maybe<PropertyDescriptor>> desc(cx);
if (!getOwnPropertyDescriptor(cx, wrapper, id, &desc)) {
return false;
}
MOZ_ASSERT(desc.isSome(),
"hasOwn() claimed we have this property, so why would we not get "
"a descriptor here?");
desc->assertComplete();
// Everything after here follows [[Get]] for ordinary objects.
if (desc->isDataDescriptor()) {
vp.set(desc->value());
return true;
}
MOZ_ASSERT(desc->isAccessorDescriptor());
RootedObject getter(cx, desc->getter());
if (!getter) {
vp.setUndefined();
return true;
}
return Call(cx, receiver, getter, HandleValueArray::empty(), vp);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::set(JSContext* cx, HandleObject wrapper,
HandleId id, HandleValue v,
HandleValue receiver,
ObjectOpResult& result) const {
MOZ_CRASH("Shouldn't be called: we return true for hasPrototype()");
return false;
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::has(JSContext* cx, HandleObject wrapper,
HandleId id, bool* bp) const {
MOZ_CRASH("Shouldn't be called: we return true for hasPrototype()");
return false;
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::hasOwn(JSContext* cx, HandleObject wrapper,
HandleId id, bool* bp) const {
// Skip our Base if it isn't already ProxyHandler.
return js::BaseProxyHandler::hasOwn(cx, wrapper, id, bp);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::getOwnEnumerablePropertyKeys(
JSContext* cx, HandleObject wrapper, MutableHandleIdVector props) const {
// Skip our Base if it isn't already ProxyHandler.
return js::BaseProxyHandler::getOwnEnumerablePropertyKeys(cx, wrapper, props);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::enumerate(
JSContext* cx, HandleObject wrapper,
JS::MutableHandleIdVector props) const {
MOZ_CRASH("Shouldn't be called: we return true for hasPrototype()");
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::call(JSContext* cx, HandleObject wrapper,
const JS::CallArgs& args) const {
assertEnteredPolicy(cx, wrapper, JS::PropertyKey::Void(),
BaseProxyHandler::CALL);
// Hard cast the singleton since SecurityWrapper doesn't have one.
return Traits::call(cx, wrapper, args, Base::singleton);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::construct(JSContext* cx, HandleObject wrapper,
const JS::CallArgs& args) const {
assertEnteredPolicy(cx, wrapper, JS::PropertyKey::Void(),
BaseProxyHandler::CALL);
// Hard cast the singleton since SecurityWrapper doesn't have one.
return Traits::construct(cx, wrapper, args, Base::singleton);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::getBuiltinClass(JSContext* cx,
JS::HandleObject wrapper,
js::ESClass* cls) const {
return Traits::getBuiltinClass(cx, wrapper, Base::singleton, cls);
}
template <typename Base, typename Traits>
const char* XrayWrapper<Base, Traits>::className(JSContext* cx,
HandleObject wrapper) const {
return Traits::className(cx, wrapper, Base::singleton);
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::getPrototype(
JSContext* cx, JS::HandleObject wrapper,
JS::MutableHandleObject protop) const {
// We really only want this override for non-SecurityWrapper-inheriting
// |Base|. But doing that statically with templates requires partial method
// specializations (and therefore a helper class), which is all more trouble
// than it's worth. Do a dynamic check.
if (Base::hasSecurityPolicy()) {
return Base::getPrototype(cx, wrapper, protop);
}
RootedObject target(cx, Traits::getTargetObject(wrapper));
RootedObject expando(cx);
if (!Traits::singleton.getExpandoObject(cx, target, wrapper, &expando)) {
return false;
}
// We want to keep the Xray's prototype distinct from that of content, but
// only if there's been a set. If there's not an expando, or the expando
// slot is |undefined|, hand back the default proto, appropriately wrapped.
if (expando) {
RootedValue v(cx);
{ // Scope for JSAutoRealm
JSAutoRealm ar(cx, expando);
v = JS::GetReservedSlot(expando, JSSLOT_EXPANDO_PROTOTYPE);
}
if (!v.isUndefined()) {
protop.set(v.toObjectOrNull());
return JS_WrapObject(cx, protop);
}
}
// Check our holder, and cache there if we don't have it cached already.
RootedObject holder(cx, Traits::singleton.ensureHolder(cx, wrapper));
if (!holder) {
return false;
}
Value cached = JS::GetReservedSlot(holder, Traits::HOLDER_SLOT_CACHED_PROTO);
if (cached.isUndefined()) {
if (!Traits::singleton.getPrototype(cx, wrapper, target, protop)) {
return false;
}
JS::SetReservedSlot(holder, Traits::HOLDER_SLOT_CACHED_PROTO,
ObjectOrNullValue(protop));
} else {
protop.set(cached.toObjectOrNull());
}
return true;
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::setPrototype(JSContext* cx,
JS::HandleObject wrapper,
JS::HandleObject proto,
JS::ObjectOpResult& result) const {
// Do this only for non-SecurityWrapper-inheriting |Base|. See the comment
// in getPrototype().
if (Base::hasSecurityPolicy()) {
return Base::setPrototype(cx, wrapper, proto, result);
}
RootedObject target(cx, Traits::getTargetObject(wrapper));
RootedObject expando(
cx, Traits::singleton.ensureExpandoObject(cx, wrapper, target));
if (!expando) {
return false;
}
// The expando lives in the target's realm, so do our installation there.
JSAutoRealm ar(cx, target);
RootedValue v(cx, ObjectOrNullValue(proto));
if (!JS_WrapValue(cx, &v)) {
return false;
}
JS_SetReservedSlot(expando, JSSLOT_EXPANDO_PROTOTYPE, v);
return result.succeed();
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::getPrototypeIfOrdinary(
JSContext* cx, JS::HandleObject wrapper, bool* isOrdinary,
JS::MutableHandleObject protop) const {
// We want to keep the Xray's prototype distinct from that of content, but
// only if there's been a set. This different-prototype-over-time behavior
// means that the [[GetPrototypeOf]] trap *can't* be ECMAScript's ordinary
// [[GetPrototypeOf]]. This also covers cross-origin Window behavior that
// per
// must be non-ordinary.
*isOrdinary = false;
return true;
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::setImmutablePrototype(JSContext* cx,
JS::HandleObject wrapper,
bool* succeeded) const {
// For now, lacking an obvious place to store a bit, prohibit making an
// Xray's [[Prototype]] immutable. We can revisit this (or maybe give all
// Xrays immutable [[Prototype]], because who does this, really?) later if
// necessary.
*succeeded = false;
return true;
}
template <typename Base, typename Traits>
bool XrayWrapper<Base, Traits>::getPropertyKeys(
JSContext* cx, HandleObject wrapper, unsigned flags,
MutableHandleIdVector props) const {
assertEnteredPolicy(cx, wrapper, JS::PropertyKey::Void(),
BaseProxyHandler::ENUMERATE);
// Enumerate expando properties first. Note that the expando object lives
// in the target compartment.
RootedObject target(cx, Traits::getTargetObject(wrapper));
RootedObject expando(cx);
if (!Traits::singleton.getExpandoObject(cx, target, wrapper, &expando)) {
return false;
}
if (expando) {
JSAutoRealm ar(cx, expando);
if (!js::GetPropertyKeys(cx, expando, flags, props)) {
return false;
}
}
for (size_t i = 0; i < props.length(); ++i) {
JS_MarkCrossZoneId(cx, props[i]);
}
return Traits::singleton.enumerateNames(cx, wrapper, flags, props);
}
/*
* The Permissive / Security variants should be used depending on whether the
* compartment of the wrapper is guranteed to subsume the compartment of the
* wrapped object (i.e. - whether it is safe from a security perspective to
* unwrap the wrapper).
*/
template <typename Base, typename Traits>
const xpc::XrayWrapper<Base, Traits> xpc::XrayWrapper<Base, Traits>::singleton(
0);
template class PermissiveXrayDOM;
template class PermissiveXrayJS;
template class PermissiveXrayOpaque;
/*
* This callback is used by the JS engine to test if a proxy handler is for a
* cross compartment xray with no security requirements.
*/
static bool IsCrossCompartmentXrayCallback(
const js::BaseProxyHandler* handler) {
return handler == &PermissiveXrayDOM::singleton;
}
JS::XrayJitInfo gXrayJitInfo = {
IsCrossCompartmentXrayCallback, CompartmentHasExclusiveExpandos,
JSSLOT_XRAY_HOLDER, XrayTraits::HOLDER_SLOT_EXPANDO,
JSSLOT_EXPANDO_PROTOTYPE};
} // namespace xpc