Bug 1460433: Part 1 - Change BasicDllServices to not do any dll notification callbacks; r=mhowell

BasicDllServices is used to gain access to the authenticode APIs in non-Gecko
contexts. One feature that WinDllServices provides is the ability to register
a callback interface to be notified when a DLL has been loaded.

This is not particularly useful in the BasicDllServices use case, and in the
"handle a launcher process failure on a background thread" use case, would
actually be harmful.

This patch modifies the DLLServices backend to offer a "basic" option that
omits the callback stuff.

Differential Revision: https://phabricator.services.mozilla.com/D19696

--HG--
extra : moz-landing-system : lando

js/xpconnect/src/XPCShellImpl.cpp

@@ -1321,7 +1321,7 @@ int XRE_XPCShellMain(int argc, char** argv, char** envp,
 
     // Ensure that DLL Services are running
     RefPtr<DllServices> dllSvc(DllServices::Get());
-    auto dllServicesDisable = MakeScopeExit([&dllSvc]() { dllSvc->Disable(); });
+    auto dllServicesDisable = MakeScopeExit([&dllSvc]() { dllSvc->DisableFull(); });
 
 #  if defined(MOZ_SANDBOX)
     // Required for sandboxed child processes.

mozglue/build/WindowsDllBlocklist.cpp

@@ -994,7 +994,7 @@ namespace mozilla {
 Authenticode* GetAuthenticode();
 }  // namespace mozilla
 
-MFBT_API void DllBlocklist_SetDllServices(
+MFBT_API void DllBlocklist_SetFullDllServices(
     mozilla::glue::detail::DllServicesBase* aSvc) {
   glue::AutoExclusiveLock lock(gDllServicesLock);
   if (aSvc) {
@@ -1023,3 +1023,12 @@ MFBT_API void DllBlocklist_SetDllServices(
     }
   }
 }
+
+MFBT_API void DllBlocklist_SetBasicDllServices(
+    mozilla::glue::detail::DllServicesBase* aSvc) {
+  if (!aSvc) {
+    return;
+  }
+
+  aSvc->SetAuthenticodeImpl(GetAuthenticode());
+}

mozglue/build/WindowsDllBlocklist.h

@@ -54,7 +54,9 @@ class DllServicesBase;
 }  // namespace glue
 }  // namespace mozilla
 
-MFBT_API void DllBlocklist_SetDllServices(
+MFBT_API void DllBlocklist_SetFullDllServices(
+    mozilla::glue::detail::DllServicesBase* aSvc);
+MFBT_API void DllBlocklist_SetBasicDllServices(
     mozilla::glue::detail::DllServicesBase* aSvc);
 
 #endif  // defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))

mozglue/build/WindowsDllServices.h

@@ -110,7 +110,7 @@ class DllServicesBase : public Authenticode {
     return mAuthenticode->GetBinaryOrgName(aFilePath);
   }
 
-  void Disable() { DllBlocklist_SetDllServices(nullptr); }
+  void DisableFull() { DllBlocklist_SetFullDllServices(nullptr); }
 
   DllServicesBase(const DllServicesBase&) = delete;
   DllServicesBase(DllServicesBase&&) = delete;
@@ -122,7 +122,8 @@ class DllServicesBase : public Authenticode {
 
   virtual ~DllServicesBase() = default;
 
-  void Enable() { DllBlocklist_SetDllServices(this); }
+  void EnableFull() { DllBlocklist_SetFullDllServices(this); }
+  void EnableBasic() { DllBlocklist_SetBasicDllServices(this); }
 
  private:
   Authenticode* mAuthenticode;
@@ -166,15 +167,18 @@ class DllServices : public detail::DllServicesBase {
 
 #else
 
-class BasicDllServices : public detail::DllServicesBase {
+class BasicDllServices final : public detail::DllServicesBase {
  public:
-  BasicDllServices() { Enable(); }
-
-  ~BasicDllServices() { Disable(); }
-
-  virtual void DispatchDllLoadNotification(PCUNICODE_STRING aDllName) override {
+  BasicDllServices() {
+    EnableBasic();
   }
 
+  ~BasicDllServices() = default;
+
+  // Not useful in this class, so provide a default implementation
+  virtual void DispatchDllLoadNotification(PCUNICODE_STRING aDllName) override
+      {}
+
   virtual void NotifyUntrustedModuleLoads(
       const Vector<glue::ModuleLoadEvent, 0, InfallibleAllocPolicy>& aEvents)
       override {}

toolkit/xre/WinDllServices.cpp

@@ -396,10 +396,10 @@ DllServices* DllServices::Get() {
   sInstance = new DllServices();
   sDllServicesHasBeenSet = true;
 
-  // Enable() winds up calling NotifyUntrustedModuleLoads which requires
-  // sInstance to be valid. So we must call Enable() here rather than the
+  // EnableFull() winds up calling NotifyUntrustedModuleLoads which requires
+  // sInstance to be valid. So we must call EnableFull() here rather than the
   // DllServices constructor.
-  sInstance->Enable();
+  sInstance->EnableFull();
   ClearOnShutdown(&sInstance);
   return sInstance;
 }

toolkit/xre/nsAppRunner.cpp

@@ -4389,7 +4389,7 @@ nsresult XREMain::XRE_mainRun() {
 #if defined(XP_WIN)
   RefPtr<mozilla::DllServices> dllServices(mozilla::DllServices::Get());
   auto dllServicesDisable =
-      MakeScopeExit([&dllServices]() { dllServices->Disable(); });
+      MakeScopeExit([&dllServices]() { dllServices->DisableFull(); });
 #endif  // defined(XP_WIN)
 
 #ifdef NS_FUNCTION_TIMER