ntdll: Check for NULL attr in NtOpenKey (Coverity).

dlls/ntdll/reg.c

@@ -114,8 +114,10 @@ NTSTATUS WINAPI RtlpNtCreateKey( PHANDLE retkey, ACCESS_MASK access, const OBJEC
 NTSTATUS WINAPI NtOpenKey( PHANDLE retkey, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
 {
     NTSTATUS ret;
-    DWORD len = attr->ObjectName->Length;
+    DWORD len;
 
+    if (!attr) return STATUS_ACCESS_VIOLATION;
+    len = attr->ObjectName->Length;
     TRACE( "(%p,%s,%x,%p)\n", attr->RootDirectory,
            debugstr_us(attr->ObjectName), access, retkey );
 

dlls/ntdll/tests/reg.c

@@ -336,9 +336,6 @@ static void test_NtOpenKey(void)
     OBJECT_ATTRIBUTES attr;
     ACCESS_MASK am = KEY_READ;
 
-    if (0)
-    {
-    /* Crashes Wine */
     /* All NULL */
     status = pNtOpenKey(NULL, 0, NULL);
     ok(status == STATUS_ACCESS_VIOLATION, "Expected STATUS_ACCESS_VIOLATION, got: 0x%08x\n", status);
@@ -347,7 +344,6 @@ static void test_NtOpenKey(void)
     status = pNtOpenKey(&key, 0, NULL);
     ok(status == STATUS_ACCESS_VIOLATION /* W2K3/XP/W2K */ || status == STATUS_INVALID_PARAMETER /* NT4 */,
         "Expected STATUS_ACCESS_VIOLATION or STATUS_INVALID_PARAMETER(NT4), got: 0x%08x\n", status);
-    }
 
     InitializeObjectAttributes(&attr, &winetestpath, 0, 0, 0);