1 files changed, 171 insertions, 0 deletions
diff --git a/js/xpconnect/wrappers/AccessCheck.cpp b/js/xpconnect/wrappers/AccessCheck.cpp
new file mode 100644
index 0000000000..a3c5173776
--- /dev/null
+++ b/js/xpconnect/wrappers/AccessCheck.cpp
@@ -0,0 +1,171 @@
+/* -*- 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 "AccessCheck.h"
+
+#include "nsJSPrincipals.h"
+
+#include "XPCWrapper.h"
+#include "XrayWrapper.h"
+#include "FilteringWrapper.h"
+
+#include "jsfriendapi.h"
+#include "js/Object.h"  // JS::GetClass, JS::GetCompartment
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/LocationBinding.h"
+#include "mozilla/dom/WindowBinding.h"
+#include "nsJSUtils.h"
+#include "xpcprivate.h"
+
+using namespace mozilla;
+using namespace JS;
+using namespace js;
+
+namespace xpc {
+
+BasePrincipal* GetRealmPrincipal(JS::Realm* realm) {
+  return BasePrincipal::Cast(
+      nsJSPrincipals::get(JS::GetRealmPrincipals(realm)));
+}
+
+nsIPrincipal* GetObjectPrincipal(JSObject* obj) {
+  return GetRealmPrincipal(js::GetNonCCWObjectRealm(obj));
+}
+
+bool AccessCheck::subsumes(JSObject* a, JSObject* b) {
+  return CompartmentOriginInfo::Subsumes(JS::GetCompartment(a),
+                                         JS::GetCompartment(b));
+}
+
+// Same as above, but considering document.domain.
+bool AccessCheck::subsumesConsideringDomain(JS::Realm* a, JS::Realm* b) {
+  MOZ_ASSERT(OriginAttributes::IsRestrictOpenerAccessForFPI());
+  BasePrincipal* aprin = GetRealmPrincipal(a);
+  BasePrincipal* bprin = GetRealmPrincipal(b);
+  return aprin->FastSubsumesConsideringDomain(bprin);
+}
+
+bool AccessCheck::subsumesConsideringDomainIgnoringFPD(JS::Realm* a,
+                                                       JS::Realm* b) {
+  MOZ_ASSERT(!OriginAttributes::IsRestrictOpenerAccessForFPI());
+  BasePrincipal* aprin = GetRealmPrincipal(a);
+  BasePrincipal* bprin = GetRealmPrincipal(b);
+  return aprin->FastSubsumesConsideringDomainIgnoringFPD(bprin);
+}
+
+// Does the compartment of the wrapper subsumes the compartment of the wrappee?
+bool AccessCheck::wrapperSubsumes(JSObject* wrapper) {
+  MOZ_ASSERT(js::IsWrapper(wrapper));
+  JSObject* wrapped = js::UncheckedUnwrap(wrapper);
+  return CompartmentOriginInfo::Subsumes(JS::GetCompartment(wrapper),
+                                         JS::GetCompartment(wrapped));
+}
+
+bool AccessCheck::isChrome(JS::Compartment* compartment) {
+  return js::IsSystemCompartment(compartment);
+}
+
+bool AccessCheck::isChrome(JS::Realm* realm) {
+  return isChrome(JS::GetCompartmentForRealm(realm));
+}
+
+bool AccessCheck::isChrome(JSObject* obj) {
+  return isChrome(JS::GetCompartment(obj));
+}
+
+bool IsCrossOriginAccessibleObject(JSObject* obj) {
+  obj = js::UncheckedUnwrap(obj, /* stopAtWindowProxy = */ false);
+  const JSClass* clasp = JS::GetClass(obj);
+
+  return (clasp->name[0] == 'L' && !strcmp(clasp->name, "Location")) ||
+         (clasp->name[0] == 'W' && !strcmp(clasp->name, "Window"));
+}
+
+bool AccessCheck::checkPassToPrivilegedCode(JSContext* cx, HandleObject wrapper,
+                                            HandleValue v) {
+  // Primitives are fine.
+  if (!v.isObject()) {
+    return true;
+  }
+  RootedObject obj(cx, &v.toObject());
+
+  // Non-wrappers are fine.
+  if (!js::IsWrapper(obj)) {
+    return true;
+  }
+
+  // Same-origin wrappers are fine.
+  if (AccessCheck::wrapperSubsumes(obj)) {
+    return true;
+  }
+
+  // Badness.
+  JS_ReportErrorASCII(cx,
+                      "Permission denied to pass object to privileged code");
+  return false;
+}
+
+bool AccessCheck::checkPassToPrivilegedCode(JSContext* cx, HandleObject wrapper,
+                                            const CallArgs& args) {
+  if (!checkPassToPrivilegedCode(cx, wrapper, args.thisv())) {
+    return false;
+  }
+  for (size_t i = 0; i < args.length(); ++i) {
+    if (!checkPassToPrivilegedCode(cx, wrapper, args[i])) {
+      return false;
+    }
+  }
+  return true;
+}
+
+void AccessCheck::reportCrossOriginDenial(JSContext* cx, JS::HandleId id,
+                                          const nsACString& accessType) {
+  // This function exists because we want to report DOM SecurityErrors, not JS
+  // Errors, when denying access on cross-origin DOM objects.  It's
+  // conceptually pretty similar to
+  // AutoEnterPolicy::reportErrorIfExceptionIsNotPending.
+  if (JS_IsExceptionPending(cx)) {
+    return;
+  }
+
+  nsAutoCString message;
+  if (id.isVoid()) {
+    message = "Permission denied to access object"_ns;
+  } else {
+    // We want to use JS_ValueToSource here, because that most closely
+    // matches what AutoEnterPolicy::reportErrorIfExceptionIsNotPending
+    // does.
+    JS::RootedValue idVal(cx, js::IdToValue(id));
+    nsAutoJSString propName;
+    JS::RootedString idStr(cx, JS_ValueToSource(cx, idVal));
+    if (!idStr || !propName.init(cx, idStr)) {
+      return;
+    }
+    message = "Permission denied to "_ns + accessType + " property "_ns +
+              NS_ConvertUTF16toUTF8(propName) + " on cross-origin object"_ns;
+  }
+  ErrorResult rv;
+  rv.ThrowSecurityError(message);
+  MOZ_ALWAYS_TRUE(rv.MaybeSetPendingException(cx));
+}
+
+bool OpaqueWithSilentFailing::deny(JSContext* cx, js::Wrapper::Action act,
+                                   HandleId id, bool mayThrow) {
+  // Fail silently for GET, ENUMERATE, and GET_PROPERTY_DESCRIPTOR.
+  if (act == js::Wrapper::GET || act == js::Wrapper::ENUMERATE ||
+      act == js::Wrapper::GET_PROPERTY_DESCRIPTOR) {
+    // Note that ReportWrapperDenial doesn't do any _exception_ reporting,
+    // so we want to do this regardless of the value of mayThrow.
+    return ReportWrapperDenial(cx, id, WrapperDenialForCOW,
+                               "Access to privileged JS object not permitted");
+  }
+
+  return false;
+}
+
+}  // namespace xpc