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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /js/xpconnect/wrappers/XrayWrapper.cpp
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'js/xpconnect/wrappers/XrayWrapper.cpp')
-rw-r--r--js/xpconnect/wrappers/XrayWrapper.cpp2351
1 files changed, 2351 insertions, 0 deletions
diff --git a/js/xpconnect/wrappers/XrayWrapper.cpp b/js/xpconnect/wrappers/XrayWrapper.cpp
new file mode 100644
index 0000000000..cdedb02a5f
--- /dev/null
+++ b/js/xpconnect/wrappers/XrayWrapper.cpp
@@ -0,0 +1,2351 @@
+/* -*- 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/. */
+
+#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). "
+ "See https://developer.mozilla.org/en-US/docs/Xray_vision "
+ "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 (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));
+ MOZ_ASSERT(mozilla::dom::HasConstructor(obj));
+ const JSClass* clasp = JS::GetClass(obj);
+ // See comments in DOMXrayTraits::call() explaining what's going on here.
+ if (clasp->flags & JSCLASS_IS_DOMIFACEANDPROTOJSCLASS) {
+ if (JSNative construct = clasp->getConstruct()) {
+ if (!construct(cx, args.length(), args.base())) {
+ return false;
+ }
+ } else {
+ RootedValue v(cx, ObjectValue(*wrapper));
+ js::ReportIsNotFunction(cx, v);
+ return false;
+ }
+ } else {
+ 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
+ // doing that via JSAPI used to be a lot of trouble. See bug 1135997.
+ 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
+ // <https://html.spec.whatwg.org/multipage/browsers.html#windowproxy-getprototypeof>
+ // 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