Bug 1842921 - Disable Win32k Lockdown on Audio Decoding Utility Process to avoid shutdown crash. r=bobowen

Differential Revision: https://phabricator.services.mozilla.com/D183359

security/sandbox/common/test/SandboxTestingChild.cpp

@@ -91,16 +91,17 @@ void SandboxTestingChild::Bind(Endpoint<PSandboxTestingChild>&& aEndpoint) {
     switch (s->mSandbox) {
       case ipc::SandboxingKind::GENERIC_UTILITY:
         RunTestsGenericUtility(this);
+        break;
 #ifdef MOZ_APPLEMEDIA
-        [[fallthrough]];
       case ipc::SandboxingKind::UTILITY_AUDIO_DECODING_APPLE_MEDIA:
-#endif
-#ifdef XP_WIN
-        [[fallthrough]];
-      case ipc::SandboxingKind::UTILITY_AUDIO_DECODING_WMF:
-#endif
         RunTestsUtilityAudioDecoder(this, s->mSandbox);
         break;
+#endif
+#ifdef XP_WIN
+      case ipc::SandboxingKind::UTILITY_AUDIO_DECODING_WMF:
+        RunTestsUtilityAudioDecoder(this, s->mSandbox);
+        break;
+#endif
 
       default:
         MOZ_ASSERT(false, "Invalid SandboxingKind");

security/sandbox/common/test/SandboxTestingChildTests.h

@@ -841,7 +841,7 @@ void RunTestsUtilityAudioDecoder(SandboxTestingChild* child,
 #  endif           // XP_MACOSX
 #else              // XP_UNIX
 #  ifdef XP_WIN
-  RunWinTestWin32k(child);
+  RunWinTestWin32k(child, false);
 #  endif  // XP_WIN
   child->ReportNoTests();
 #endif    // XP_UNIX

security/sandbox/win/src/sandboxbroker/sandboxBroker.cpp

@@ -1500,6 +1500,7 @@ struct GenericUtilitySandboxProps : public UtilitySandboxProps {};
 struct UtilityAudioDecodingWmfSandboxProps : public UtilitySandboxProps {
   UtilityAudioDecodingWmfSandboxProps() {
     mDelayedTokenLevel = sandbox::USER_LIMITED;
+    mUseWin32kLockdown = false;
     mDelayedMitigations = sandbox::MITIGATION_STRICT_HANDLE_CHECKS |
                           sandbox::MITIGATION_DLL_SEARCH_ORDER;
 #ifdef MOZ_WMF