Allow E_IMPL from BA/bext and check all cbSizes from BA/bext.

1 files changed, 30 insertions, 0 deletions

diff --git a/src/engine/externalengine.cpp b/src/engine/externalengine.cpp
new file mode 100644
index 00000000..ef4f931d
--- /dev/null
+++ b/src/engine/externalengine.cpp
@@ -0,0 +1,30 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include "precomp.h"
+
+
+// function definitions
+
+// TODO: callers need to provide the original size (at the time of first public release) of the struct instead of the current size.
+HRESULT WINAPI ExternalEngineValidateMessageParameter(
+    __in_opt const LPVOID pv,
+    __in SIZE_T cbSizeOffset,
+    __in DWORD dwMinimumSize
+    )
+{
+    HRESULT hr = S_OK;
+
+    if (!pv)
+    {
+        ExitFunction1(hr = E_INVALIDARG);
+    }
+
+    DWORD cbSize = *(DWORD*)((BYTE*)pv + cbSizeOffset);
+    if (dwMinimumSize < cbSize)
+    {
+        ExitFunction1(hr = E_INVALIDARG);
+    }
+
+LExit:
+    return hr;
+}