Backed out changeset 89446bf8d6b8 (bug 1215167) for introducing a hazard

--HG--
extra : commitid : 19K8BX0d4Wz

dom/base/test/chrome/cpows_child.js

@@ -20,7 +20,6 @@ var Cu = Components.utils;
     lifetime_test,
     cancel_test,
     cancel_test2,
-    unsafe_test,
   ];
 
   function go() {
@@ -338,20 +337,3 @@ function cancel_test2(finish)
     if (fin1 && fin2) finish();
   });
 }
-
-function unsafe_test(finish)
-{
-  if (!is_remote) {
-    // Only run this test when running out-of-process.
-    finish();
-    return;
-  }
-
-  function f() {}
-
-  sendAsyncMessage("cpows:unsafe", null, {f});
-  addMessageListener("cpows:unsafe_done", msg => {
-    sendRpcMessage("cpows:safe", null, {f});
-    addMessageListener("cpows:safe_done", finish);
-  });
-}

dom/base/test/chrome/cpows_parent.xul

@@ -390,33 +390,6 @@
       msg.target.messageManager.sendAsyncMessage("cpows:cancel_test2_done");
     }
 
-    function recvUnsafe(msg) {
-      let failed = false;
-
-      const PREF_UNSAFE_FORBIDDEN = "dom.ipc.cpows.forbid-unsafe-from-browser";
-      opener.wrappedJSObject.SpecialPowers.setBoolPref(PREF_UNSAFE_FORBIDDEN, true);
-      try {
-        msg.objects.f();
-      } catch (e if /unsafe CPOW usage forbidden/.test(String(e))) {
-        failed = true;
-      }
-      opener.wrappedJSObject.SpecialPowers.clearUserPref(PREF_UNSAFE_FORBIDDEN);
-      ok(failed, "CPOW should fail when unsafe");
-      msg.target.messageManager.sendAsyncMessage("cpows:unsafe_done");
-    }
-
-    function recvSafe(msg) {
-      const PREF_UNSAFE_FORBIDDEN = "dom.ipc.cpows.forbid-unsafe-from-browser";
-      opener.wrappedJSObject.SpecialPowers.setBoolPref(PREF_UNSAFE_FORBIDDEN, true);
-      try {
-        msg.objects.f();
-      } catch (e if /unsafe CPOW usage forbidden/.test(String(e))) {
-        ok(false, "cpow failed");
-      }
-      opener.wrappedJSObject.SpecialPowers.clearUserPref(PREF_UNSAFE_FORBIDDEN);
-      msg.target.messageManager.sendAsyncMessage("cpows:safe_done");
-    }
-
     function run_tests(type) {
       info("Running tests: " + type);
       var node = document.getElementById('cpowbrowser_' + type);
@@ -456,8 +429,6 @@
       mm.addMessageListener("cpows:cancel_test", recvCancelTest);
       mm.addMessageListener("cpows:cancel_sync_message", recvCancelSyncMessage);
       mm.addMessageListener("cpows:cancel_test2", recvCancelTest2);
-      mm.addMessageListener("cpows:unsafe", recvUnsafe);
-      mm.addMessageListener("cpows:safe", recvSafe);
       mm.loadFrameScript("chrome://mochitests/content/chrome/dom/base/test/chrome/cpows_child.js", true);
     }
 

dom/ipc/ContentParent.cpp

@@ -1894,6 +1894,28 @@ ContentParent::OnChannelError()
     PContentParent::OnChannelError();
 }
 
+void
+ContentParent::OnBeginSyncTransaction() {
+    if (XRE_IsParentProcess()) {
+        nsCOMPtr<nsIConsoleService> console(do_GetService(NS_CONSOLESERVICE_CONTRACTID));
+        JSContext *cx = nsContentUtils::GetCurrentJSContext();
+        if (!sDisableUnsafeCPOWWarnings) {
+            if (console && cx) {
+                nsAutoString filename;
+                uint32_t lineno = 0, column = 0;
+                nsJSUtils::GetCallingLocation(cx, filename, &lineno, &column);
+                nsCOMPtr<nsIScriptError> error(do_CreateInstance(NS_SCRIPTERROR_CONTRACTID));
+                error->Init(NS_LITERAL_STRING("unsafe CPOW usage"), filename,
+                            EmptyString(), lineno, column,
+                            nsIScriptError::warningFlag, "chrome javascript");
+                console->LogMessage(error);
+            } else {
+                NS_WARNING("Unsafe synchronous IPC message");
+            }
+        }
+    }
+}
+
 void
 ContentParent::OnChannelConnected(int32_t pid)
 {

dom/ipc/ContentParent.h

@@ -325,6 +325,8 @@ public:
 
     virtual void OnChannelError() override;
 
+    virtual void OnBeginSyncTransaction() override;
+
     virtual PCrashReporterParent*
     AllocPCrashReporterParent(const NativeThreadId& tid,
                               const uint32_t& processType) override;

ipc/glue/MessageChannel.cpp

@@ -848,6 +848,9 @@ MessageChannel::Send(Message* aMsg, Message* aReply)
     AssertWorkerThread();
     mMonitor->AssertNotCurrentThreadOwns();
 
+    if (mCurrentTransaction == 0)
+        mListener->OnBeginSyncTransaction();
+
 #ifdef OS_WIN
     SyncStackFrame frame(this, false);
     NeuteredWindowRegion neuteredRgn(mFlags & REQUIRE_DEFERRED_MESSAGE_PROTECTION);

ipc/glue/MessageChannel.h

@@ -143,7 +143,6 @@ class MessageChannel : HasResultCodes
         return !mCxxStackFrames.empty();
     }
 
-    bool IsInTransaction() const { return mCurrentTransaction != 0; }
     void CancelCurrentTransaction();
 
     /**

ipc/glue/MessageLink.h

@@ -88,6 +88,10 @@ class MessageListener
     virtual void OnExitedCall() {
         NS_RUNTIMEABORT("default impl shouldn't be invoked");
     }
+    /* This callback is called when a sync message is sent that begins a new IPC transaction
+       (i.e., when it is not part of an existing sequence of nested messages). */
+    virtual void OnBeginSyncTransaction() {
+    }
     virtual RacyInterruptPolicy MediateInterruptRace(const Message& parent,
                                                      const Message& child)
     {

js/ipc/JavaScriptChild.h

@@ -25,8 +25,6 @@ class JavaScriptChild : public JavaScriptBase<PJavaScriptChild>
 
     void drop(JSObject* obj);
 
-    bool allowMessage(JSContext* cx) override { return true; }
-
   protected:
     virtual bool isParent() override { return false; }
     virtual JSObject* scopeForTargetObjects() override;

js/ipc/JavaScriptParent.cpp

@@ -48,54 +48,6 @@ JavaScriptParent::init()
     return true;
 }
 
-static bool
-ForbidUnsafeBrowserCPOWs()
-{
-    static bool result;
-    static bool cached = false;
-    if (!cached) {
-        cached = true;
-        Preferences::AddBoolVarCache(&result, "dom.ipc.cpows.forbid-unsafe-from-browser", false);
-    }
-    return result;
-}
-
-bool
-JavaScriptParent::allowMessage(JSContext* cx)
-{
-    MessageChannel* channel = GetIPCChannel();
-    if (channel->IsInTransaction())
-        return true;
-
-    if (ForbidUnsafeBrowserCPOWs()) {
-        if (JSObject* global = JS::CurrentGlobalOrNull(cx)) {
-            if (!JS::AddonIdOfObject(global)) {
-                JS_ReportError(cx, "unsafe CPOW usage forbidden");
-                return false;
-            }
-        }
-    }
-
-    static bool disableUnsafeCPOWWarnings = PR_GetEnv("DISABLE_UNSAFE_CPOW_WARNINGS");
-    if (!disableUnsafeCPOWWarnings) {
-        nsCOMPtr<nsIConsoleService> console(do_GetService(NS_CONSOLESERVICE_CONTRACTID));
-        if (console && cx) {
-            nsAutoString filename;
-            uint32_t lineno = 0, column = 0;
-            nsJSUtils::GetCallingLocation(cx, filename, &lineno, &column);
-            nsCOMPtr<nsIScriptError> error(do_CreateInstance(NS_SCRIPTERROR_CONTRACTID));
-            error->Init(NS_LITERAL_STRING("unsafe CPOW usage"), filename,
-                        EmptyString(), lineno, column,
-                        nsIScriptError::warningFlag, "chrome javascript");
-            console->LogMessage(error);
-        } else {
-            NS_WARNING("Unsafe synchronous IPC message");
-        }
-    }
-
-    return true;
-}
-
 void
 JavaScriptParent::trace(JSTracer* trc)
 {

js/ipc/JavaScriptParent.h

@@ -25,8 +25,6 @@ class JavaScriptParent : public JavaScriptBase<PJavaScriptParent>
 
     void drop(JSObject* obj);
 
-    bool allowMessage(JSContext* cx) override;
-
     mozilla::ipc::IProtocol*
     CloneProtocol(Channel* aChannel, ProtocolCloneContext* aCtx) override;
 

js/ipc/WrapperOwner.cpp

@@ -150,9 +150,6 @@ const CPOWProxyHandler CPOWProxyHandler::singleton;
         JS_ReportError(cx, "cannot use a CPOW whose process is gone");  \
         return false;                                                   \
     }                                                                   \
-    if (!owner->allowMessage(cx)) {                                     \
-        return false;                                                   \
-    }                                                                   \
     {                                                                   \
         CPOWTimer timer(cx);                                            \
         return owner->call args;                                        \

js/ipc/WrapperOwner.h

@@ -74,8 +74,6 @@ class WrapperOwner : public virtual JavaScriptShared
 
     bool active() { return !inactive_; }
 
-    virtual bool allowMessage(JSContext* cx) = 0;
-
     void drop(JSObject* obj);
     void updatePointer(JSObject* obj, const JSObject* old);