[resend PATCH] ntdll: Tolerate null handle in DeregisterWait

[Keno Fischer]

Noticed in libuv, which is not particularly careful about whether or not
the handle it's passing to UnregisterWait is valid or NULL. Windows
has an explicit NULL check here and returns ERROR_INVALID_HANDLE.

Fixes https://github.com/JuliaLang/julia/issues/18070.

Signed-off-by: Keno Fischer <keno at juliacomputing.com>
---
 dlls/kernel32/tests/thread.c | 5 +++++
 dlls/ntdll/threadpool.c      | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/dlls/kernel32/tests/thread.c b/dlls/kernel32/tests/thread.c
index a9a04df..44c6278 100644
--- a/dlls/kernel32/tests/thread.c
+++ b/dlls/kernel32/tests/thread.c
@@ -1245,6 +1245,11 @@ static void test_RegisterWaitForSingleObject(void)
 
     ret = pUnregisterWait(wait_handle);
     ok(ret, "UnregisterWait failed with error %d\n", GetLastError());
+
+    /* Test UnregisterWait null argument case */
+    ret = pUnregisterWait(0);
+    ok(!ret && GetLastError() == ERROR_INVALID_HANDLE,
+        "UnregisterWait failed with unexpected error %d\n", GetLastError());
 }
 
 static DWORD LS_main;
diff --git a/dlls/ntdll/threadpool.c b/dlls/ntdll/threadpool.c
index 799245c..9ff0122 100644
--- a/dlls/ntdll/threadpool.c
+++ b/dlls/ntdll/threadpool.c
@@ -637,6 +637,9 @@ NTSTATUS WINAPI RtlDeregisterWaitEx(HANDLE WaitHandle, HANDLE CompletionEvent)
 
     TRACE( "(%p)\n", WaitHandle );
 
+    if (WaitHandle == NULL)
+        return STATUS_INVALID_HANDLE;
+
     NtSetEvent( wait_work_item->CancelEvent, NULL );
     if (wait_work_item->CallbackInProgress)
     {
-- 
2.7.4