The Tor Browser: dom/bindings/DOMJSProxyHandler.cpp@97036ab72558 (annotated)

dom/bindings/DOMJSProxyHandler.cpp@97036ab72558 (annotated)

dom/bindings/DOMJSProxyHandler.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * vim: set ts=2 sw=2 et tw=99 ft=cpp: */
 /* 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 "mozilla/dom/DOMJSProxyHandler.h"
 #include "xpcpublic.h"
 #include "xpcprivate.h"
 #include "XPCQuickStubs.h"
 #include "XPCWrapper.h"
 #include "WrapperFactory.h"
 #include "nsDOMClassInfo.h"
 #include "nsWrapperCacheInlines.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "jsapi.h"
 using namespace JS;
 namespace mozilla {
 namespace dom {
 jsid s_length_id = JSID_VOID;
 bool
 DefineStaticJSVals(JSContext* cx)
 {
   return InternJSString(cx, s_length_id, "length");
 }
 const char HandlerFamily = 0;
 js::DOMProxyShadowsResult
 DOMProxyShadows(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id)
 {
   JS::Value v = js::GetProxyExtra(proxy, JSPROXYSLOT_EXPANDO);
   if (v.isObject()) {
     bool hasOwn;
     Rooted<JSObject*> object(cx, &v.toObject());
     if (!JS_AlreadyHasOwnPropertyById(cx, object, id, &hasOwn))
       return js::ShadowCheckFailed;
     return hasOwn ? js::Shadows : js::DoesntShadow;
   }
   if (v.isUndefined()) {
     return js::DoesntShadow;
   }
   bool hasOwn;
   if (!GetProxyHandler(proxy)->hasOwn(cx, proxy, id, &hasOwn))
     return js::ShadowCheckFailed;
   return hasOwn ? js::Shadows : js::DoesntShadowUnique;
 }
 // Store the information for the specialized ICs.
 struct SetDOMProxyInformation
 {
   SetDOMProxyInformation() {
     js::SetDOMProxyInformation((const void*) &HandlerFamily,
                                js::PROXY_EXTRA_SLOT + JSPROXYSLOT_EXPANDO, DOMProxyShadows);
   }
 };
 SetDOMProxyInformation gSetDOMProxyInformation;
 // static
 JSObject*
 DOMProxyHandler::GetAndClearExpandoObject(JSObject* obj)
 {
   MOZ_ASSERT(IsDOMProxy(obj), "expected a DOM proxy object");
   JS::Value v = js::GetProxyExtra(obj, JSPROXYSLOT_EXPANDO);
   if (v.isUndefined()) {
     return nullptr;
   }
   if (v.isObject()) {
     js::SetProxyExtra(obj, JSPROXYSLOT_EXPANDO, UndefinedValue());
     XPCWrappedNativeScope* scope = xpc::MaybeGetObjectScope(obj);
     if (scope) {
       scope->RemoveDOMExpandoObject(obj);
     }
   } else {
     js::ExpandoAndGeneration* expandoAndGeneration =
       static_cast<js::ExpandoAndGeneration*>(v.toPrivate());
     v = expandoAndGeneration->expando;
     if (v.isUndefined()) {
       return nullptr;
     }
     expandoAndGeneration->expando = UndefinedValue();
   }
   return &v.toObject();
 }
 // static
 JSObject*
 DOMProxyHandler::EnsureExpandoObject(JSContext* cx, JS::Handle<JSObject*> obj)
 {
   NS_ASSERTION(IsDOMProxy(obj), "expected a DOM proxy object");
   JS::Value v = js::GetProxyExtra(obj, JSPROXYSLOT_EXPANDO);
   if (v.isObject()) {
     return &v.toObject();
   }
   js::ExpandoAndGeneration* expandoAndGeneration;
   if (!v.isUndefined()) {
     expandoAndGeneration = static_cast<js::ExpandoAndGeneration*>(v.toPrivate());
     if (expandoAndGeneration->expando.isObject()) {
       return &expandoAndGeneration->expando.toObject();
     }
   } else {
     expandoAndGeneration = nullptr;
   }
   JS::Rooted<JSObject*> parent(cx, js::GetObjectParent(obj));
   JS::Rooted<JSObject*> expando(cx,
     JS_NewObjectWithGivenProto(cx, nullptr, JS::NullPtr(), parent));
   if (!expando) {
     return nullptr;
   }
   nsISupports* native = UnwrapDOMObject<nsISupports>(obj);
   nsWrapperCache* cache;
   CallQueryInterface(native, &cache);
   if (expandoAndGeneration) {
     cache->PreserveWrapper(native);
     expandoAndGeneration->expando.setObject(*expando);
     return expando;
   }
   XPCWrappedNativeScope* scope = xpc::GetObjectScope(obj);
   if (!scope->RegisterDOMExpandoObject(obj)) {
     return nullptr;
   }
   cache->SetPreservingWrapper(true);
   js::SetProxyExtra(obj, JSPROXYSLOT_EXPANDO, ObjectValue(*expando));
   return expando;
 }
 bool
 DOMProxyHandler::isExtensible(JSContext *cx, JS::Handle<JSObject*> proxy, bool *extensible)
 {
   // always extensible per WebIDL
   *extensible = true;
   return true;
 }
 bool
 DOMProxyHandler::preventExtensions(JSContext *cx, JS::Handle<JSObject*> proxy)
 {
   // Throw a TypeError, per WebIDL.
   JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr,
                        JSMSG_CANT_CHANGE_EXTENSIBILITY);
   return false;
 }
 bool
 BaseDOMProxyHandler::getPropertyDescriptor(JSContext* cx,
                                            JS::Handle<JSObject*> proxy,
                                            JS::Handle<jsid> id,
                                            MutableHandle<JSPropertyDescriptor> desc)
 {
   if (!getOwnPropertyDescriptor(cx, proxy, id, desc)) {
     return false;
   }
   if (desc.object()) {
     return true;
   }
   JS::Rooted<JSObject*> proto(cx);
   if (!js::GetObjectProto(cx, proxy, &proto)) {
     return false;
   }
   if (!proto) {
     desc.object().set(nullptr);
     return true;
   }
   return JS_GetPropertyDescriptorById(cx, proto, id, desc);
 }
 bool
 BaseDOMProxyHandler::getOwnPropertyDescriptor(JSContext* cx,
                                               JS::Handle<JSObject*> proxy,
                                               JS::Handle<jsid> id,
                                               MutableHandle<JSPropertyDescriptor> desc)
 {
   return getOwnPropDescriptor(cx, proxy, id, /* ignoreNamedProps = */ false,
                               desc);
 }
 bool
 DOMProxyHandler::defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
                                 MutableHandle<JSPropertyDescriptor> desc, bool* defined)
 {
   if (desc.hasGetterObject() && desc.setter() == JS_StrictPropertyStub) {
     return JS_ReportErrorFlagsAndNumber(cx,
                                         JSREPORT_WARNING | JSREPORT_STRICT |
                                         JSREPORT_STRICT_MODE_ERROR,
                                         js_GetErrorMessage, nullptr,
                                         JSMSG_GETTER_ONLY);
   }
   if (xpc::WrapperFactory::IsXrayWrapper(proxy)) {
     return true;
   }
   JSObject* expando = EnsureExpandoObject(cx, proxy);
   if (!expando) {
     return false;
   }
   bool dummy;
   return js_DefineOwnProperty(cx, expando, id, desc, &dummy);
 }
 bool
 DOMProxyHandler::set(JSContext *cx, Handle<JSObject*> proxy, Handle<JSObject*> receiver,
                      Handle<jsid> id, bool strict, MutableHandle<JS::Value> vp)
 {
   MOZ_ASSERT(!xpc::WrapperFactory::IsXrayWrapper(proxy),
              "Should not have a XrayWrapper here");
   bool done;
   if (!setCustom(cx, proxy, id, vp, &done)) {
     return false;
   }
   if (done) {
     return true;
   }
   // Make sure to ignore our named properties when checking for own
   // property descriptors for a set.
   JS::Rooted<JSPropertyDescriptor> desc(cx);
   if (!getOwnPropDescriptor(cx, proxy, id, /* ignoreNamedProps = */ true,
                             &desc)) {
     return false;
   }
   bool descIsOwn = desc.object() != nullptr;
   if (!desc.object()) {
     // Don't just use getPropertyDescriptor, unlike BaseProxyHandler::set,
     // because that would call getOwnPropertyDescriptor on ourselves.  Instead,
     // directly delegate to the proto, if any.
     JS::Rooted<JSObject*> proto(cx);
     if (!js::GetObjectProto(cx, proxy, &proto)) {
       return false;
     }
     if (proto && !JS_GetPropertyDescriptorById(cx, proto, id, &desc)) {
       return false;
     }
   }
   return js::SetPropertyIgnoringNamedGetter(cx, this, proxy, receiver, id,
                                             &desc, descIsOwn, strict, vp);
 }
 bool
 DOMProxyHandler::delete_(JSContext* cx, JS::Handle<JSObject*> proxy,
                          JS::Handle<jsid> id, bool* bp)
 {
   JS::Rooted<JSObject*> expando(cx);
   if (!xpc::WrapperFactory::IsXrayWrapper(proxy) && (expando = GetExpandoObject(proxy))) {
     return JS_DeletePropertyById2(cx, expando, id, bp);
   }
   *bp = true;
   return true;
 }
 bool
 BaseDOMProxyHandler::enumerate(JSContext* cx, JS::Handle<JSObject*> proxy,
                                AutoIdVector& props)
 {
   JS::Rooted<JSObject*> proto(cx);
   if (!JS_GetPrototype(cx, proxy, &proto))  {
     return false;
   }
   return keys(cx, proxy, props) &&
          (!proto || js::GetPropertyNames(cx, proto, 0, &props));
 }
 bool
 BaseDOMProxyHandler::watch(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
                            JS::Handle<JSObject*> callable)
 {
   return js::WatchGuts(cx, proxy, id, callable);
 }
 bool
 BaseDOMProxyHandler::unwatch(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id)
 {
   return js::UnwatchGuts(cx, proxy, id);
 }
 bool
 BaseDOMProxyHandler::getOwnPropertyNames(JSContext* cx,
                                          JS::Handle<JSObject*> proxy,
                                          JS::AutoIdVector& props)
 {
   return ownPropNames(cx, proxy, JSITER_OWNONLY | JSITER_HIDDEN, props);
 }
 bool
 BaseDOMProxyHandler::keys(JSContext* cx,
                           JS::Handle<JSObject*> proxy,
                           JS::AutoIdVector& props)
 {
   return ownPropNames(cx, proxy, JSITER_OWNONLY, props);
 }
 bool
 DOMProxyHandler::has(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id, bool* bp)
 {
   if (!hasOwn(cx, proxy, id, bp)) {
     return false;
   }
   if (*bp) {
     // We have the property ourselves; no need to worry about our prototype
     // chain.
     return true;
   }
   // OK, now we have to look at the proto
   JS::Rooted<JSObject*> proto(cx);
   if (!js::GetObjectProto(cx, proxy, &proto)) {
     return false;
   }
   if (!proto) {
     return true;
   }
   bool protoHasProp;
   bool ok = JS_HasPropertyById(cx, proto, id, &protoHasProp);
   if (ok) {
     *bp = protoHasProp;
   }
   return ok;
 }
 int32_t
 IdToInt32(JSContext* cx, JS::Handle<jsid> id)
 {
   JS::Rooted<JS::Value> idval(cx);
   double array_index;
   int32_t i;
   if (!::JS_IdToValue(cx, id, &idval) ||
       !JS::ToNumber(cx, idval, &array_index) ||
       !::JS_DoubleIsInt32(array_index, &i)) {
     return -1;
   }
   return i;
 }
 bool
 DOMProxyHandler::setCustom(JSContext* cx, JS::Handle<JSObject*> proxy, JS::Handle<jsid> id,
                            JS::MutableHandle<JS::Value> vp, bool *done)
 {
   *done = false;
   return true;
 }
 } // namespace dom
 } // namespace mozilla

The Tor Browser / annotate

dom/bindings/DOMJSProxyHandler.cpp@97036ab72558 (annotated)

dom/bindings/DOMJSProxyHandler.cpp