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Diffstat (limited to '')
| -rw-r--r-- | dom/base/WindowNamedPropertiesHandler.cpp | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/dom/base/WindowNamedPropertiesHandler.cpp b/dom/base/WindowNamedPropertiesHandler.cpp new file mode 100644 index 0000000000..7601438af6 --- /dev/null +++ b/dom/base/WindowNamedPropertiesHandler.cpp @@ -0,0 +1,278 @@ +/* -*- 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 "WindowNamedPropertiesHandler.h" +#include "mozilla/dom/EventTargetBinding.h" +#include "mozilla/dom/ProxyHandlerUtils.h" +#include "mozilla/dom/WindowBinding.h" +#include "mozilla/dom/WindowProxyHolder.h" +#include "nsContentUtils.h" +#include "nsGlobalWindow.h" +#include "nsHTMLDocument.h" +#include "nsJSUtils.h" +#include "xpcprivate.h" + +namespace mozilla::dom { + +static bool ShouldExposeChildWindow(const nsString& aNameBeingResolved, + BrowsingContext* aChild) { + Element* e = aChild->GetEmbedderElement(); + if (e && e->IsInShadowTree()) { + return false; + } + + // If we're same-origin with the child, go ahead and expose it. + nsPIDOMWindowOuter* child = aChild->GetDOMWindow(); + nsCOMPtr<nsIScriptObjectPrincipal> sop = do_QueryInterface(child); + if (sop && nsContentUtils::SubjectPrincipal()->Equals(sop->GetPrincipal())) { + return true; + } + + // If we're not same-origin, expose it _only_ if the name of the browsing + // context matches the 'name' attribute of the frame element in the parent. + // The motivations behind this heuristic are worth explaining here. + // + // Historically, all UAs supported global named access to any child browsing + // context (that is to say, window.dolske returns a child frame where either + // the "name" attribute on the frame element was set to "dolske", or where + // the child explicitly set window.name = "dolske"). + // + // This is problematic because it allows possibly-malicious and unrelated + // cross-origin subframes to pollute the global namespace of their parent in + // unpredictable ways (see bug 860494). This is also problematic for browser + // engines like Servo that want to run cross-origin script on different + // threads. + // + // The naive solution here would be to filter out any cross-origin subframes + // obtained when doing named lookup in global scope. But that is unlikely to + // be web-compatible, since it will break named access for consumers that do + // <iframe name="dolske" src="http://cross-origin.com/sadtrombone.html"> and + // expect to be able to access the cross-origin subframe via named lookup on + // the global. + // + // The optimal behavior would be to do the following: + // (a) Look for any child browsing context with name="dolske". + // (b) If the result is cross-origin, null it out. + // (c) If we have null, look for a frame element whose 'name' attribute is + // "dolske". + // + // Unfortunately, (c) would require some engineering effort to be performant + // in Gecko, and probably in other UAs as well. So we go with a simpler + // approximation of the above. This approximation will only break sites that + // rely on their cross-origin subframes setting window.name to a known value, + // which is unlikely to be very common. And while it does introduce a + // dependency on cross-origin state when doing global lookups, it doesn't + // allow the child to arbitrarily pollute the parent namespace, and requires + // cross-origin communication only in a limited set of cases that can be + // computed independently by the parent. + return e && e->AttrValueIs(kNameSpaceID_None, nsGkAtoms::name, + aNameBeingResolved, eCaseMatters); +} + +bool WindowNamedPropertiesHandler::getOwnPropDescriptor( + JSContext* aCx, JS::Handle<JSObject*> aProxy, JS::Handle<jsid> aId, + bool /* unused */, + JS::MutableHandle<Maybe<JS::PropertyDescriptor>> aDesc) const { + aDesc.reset(); + + if (aId.isSymbol()) { + if (aId.isWellKnownSymbol(JS::SymbolCode::toStringTag)) { + JS::Rooted<JSString*> toStringTagStr( + aCx, JS_NewStringCopyZ(aCx, "WindowProperties")); + if (!toStringTagStr) { + return false; + } + + aDesc.set(Some( + JS::PropertyDescriptor::Data(JS::StringValue(toStringTagStr), + {JS::PropertyAttribute::Configurable}))); + return true; + } + + // Nothing to do if we're resolving another symbol property. + return true; + } + + bool hasOnPrototype; + if (!HasPropertyOnPrototype(aCx, aProxy, aId, &hasOnPrototype)) { + return false; + } + if (hasOnPrototype) { + return true; + } + + nsAutoJSString str; + if (!str.init(aCx, aId)) { + return false; + } + + if (str.IsEmpty()) { + return true; + } + + // Grab the DOM window. + nsGlobalWindowInner* win = xpc::WindowGlobalOrNull(aProxy); + if (win->Length() > 0) { + RefPtr<BrowsingContext> child = win->GetChildWindow(str); + if (child && ShouldExposeChildWindow(str, child)) { + // We found a subframe of the right name. Shadowing via |var foo| in + // global scope is still allowed, since |var| only looks up |own| + // properties. But unqualified shadowing will fail, per-spec. + JS::Rooted<JS::Value> v(aCx); + if (!ToJSValue(aCx, WindowProxyHolder(std::move(child)), &v)) { + return false; + } + aDesc.set(mozilla::Some( + JS::PropertyDescriptor::Data(v, {JS::PropertyAttribute::Configurable, + JS::PropertyAttribute::Writable}))); + return true; + } + } + + // The rest of this function is for HTML documents only. + Document* doc = win->GetExtantDoc(); + if (!doc || !doc->IsHTMLOrXHTML()) { + return true; + } + nsHTMLDocument* document = doc->AsHTMLDocument(); + + JS::Rooted<JS::Value> v(aCx); + Element* element = document->GetElementById(str); + if (element) { + if (!ToJSValue(aCx, element, &v)) { + return false; + } + aDesc.set(mozilla::Some( + JS::PropertyDescriptor::Data(v, {JS::PropertyAttribute::Configurable, + JS::PropertyAttribute::Writable}))); + return true; + } + + ErrorResult rv; + bool found = document->ResolveName(aCx, str, &v, rv); + if (rv.MaybeSetPendingException(aCx)) { + return false; + } + + if (found) { + aDesc.set(mozilla::Some( + JS::PropertyDescriptor::Data(v, {JS::PropertyAttribute::Configurable, + JS::PropertyAttribute::Writable}))); + } + return true; +} + +bool WindowNamedPropertiesHandler::defineProperty( + JSContext* aCx, JS::Handle<JSObject*> aProxy, JS::Handle<jsid> aId, + JS::Handle<JS::PropertyDescriptor> aDesc, + JS::ObjectOpResult& result) const { + return result.failCantDefineWindowNamedProperty(); +} + +bool WindowNamedPropertiesHandler::ownPropNames( + JSContext* aCx, JS::Handle<JSObject*> aProxy, unsigned flags, + JS::MutableHandleVector<jsid> aProps) const { + if (!(flags & JSITER_HIDDEN)) { + // None of our named properties are enumerable. + return true; + } + + // Grab the DOM window. + nsGlobalWindowInner* win = xpc::WindowGlobalOrNull(aProxy); + nsTArray<nsString> names; + // The names live on the outer window, which might be null + nsGlobalWindowOuter* outer = win->GetOuterWindowInternal(); + if (outer) { + if (BrowsingContext* bc = outer->GetBrowsingContext()) { + for (const auto& child : bc->Children()) { + const nsString& name = child->Name(); + if (!name.IsEmpty() && !names.Contains(name)) { + // Make sure we really would expose it from getOwnPropDescriptor. + if (ShouldExposeChildWindow(name, child)) { + names.AppendElement(name); + } + } + } + } + } + if (!AppendNamedPropertyIds(aCx, aProxy, names, false, aProps)) { + return false; + } + + names.Clear(); + Document* doc = win->GetExtantDoc(); + if (!doc || !doc->IsHTMLOrXHTML()) { + // Define to @@toStringTag on this object to keep Object.prototype.toString + // backwards compatible. + JS::Rooted<jsid> toStringTagId( + aCx, JS::GetWellKnownSymbolKey(aCx, JS::SymbolCode::toStringTag)); + return aProps.append(toStringTagId); + } + + nsHTMLDocument* document = doc->AsHTMLDocument(); + // Document names are enumerable, so we want to get them no matter what flags + // is. + document->GetSupportedNames(names); + + JS::RootedVector<jsid> docProps(aCx); + if (!AppendNamedPropertyIds(aCx, aProxy, names, false, &docProps)) { + return false; + } + + JS::Rooted<jsid> toStringTagId( + aCx, JS::GetWellKnownSymbolKey(aCx, JS::SymbolCode::toStringTag)); + if (!docProps.append(toStringTagId)) { + return false; + } + + return js::AppendUnique(aCx, aProps, docProps); +} + +bool WindowNamedPropertiesHandler::delete_(JSContext* aCx, + JS::Handle<JSObject*> aProxy, + JS::Handle<jsid> aId, + JS::ObjectOpResult& aResult) const { + return aResult.failCantDeleteWindowNamedProperty(); +} + +// Note that this class doesn't need any reserved slots, but SpiderMonkey +// asserts all proxy classes have at least one reserved slot. +static const DOMIfaceAndProtoJSClass WindowNamedPropertiesClass = { + PROXY_CLASS_DEF("WindowProperties", JSCLASS_IS_DOMIFACEANDPROTOJSCLASS | + JSCLASS_HAS_RESERVED_SLOTS(1)), + eNamedPropertiesObject, + false, + prototypes::id::_ID_Count, + 0, + &sEmptyNativePropertyHooks, + "[object WindowProperties]", + EventTarget_Binding::GetProtoObject}; + +// static +JSObject* WindowNamedPropertiesHandler::Create(JSContext* aCx, + JS::Handle<JSObject*> aProto) { + js::ProxyOptions options; + options.setClass(&WindowNamedPropertiesClass.mBase); + + JS::Rooted<JSObject*> gsp( + aCx, js::NewProxyObject(aCx, WindowNamedPropertiesHandler::getInstance(), + JS::NullHandleValue, aProto, options)); + if (!gsp) { + return nullptr; + } + + bool succeeded; + if (!JS_SetImmutablePrototype(aCx, gsp, &succeeded)) { + return nullptr; + } + MOZ_ASSERT(succeeded, + "errors making the [[Prototype]] of the named properties object " + "immutable should have been JSAPI failures, not !succeeded"); + + return gsp; +} + +} // namespace mozilla::dom |