From faf810e8cb76ce88e61591610bcb626b7a08c62b Mon Sep 17 00:00:00 2001
From: Simon Rozman <simon@rozman.si>
Date: Thu, 20 Jun 2019 12:00:21 +0200
Subject: [PATCH] Fix NdisQueryMdl() NULL-buffer check

Signed-off-by: Simon Rozman <simon@rozman.si>
---
 wintun.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/wintun.c b/wintun.c
index 3a8657c..aa201b4 100644
--- a/wintun.c
+++ b/wintun.c
@@ -258,8 +258,9 @@ static NTSTATUS TunGetIrpBuffer(_In_ IRP *Irp, _Out_ UCHAR **buffer, _Out_ ULONG
 	if (!Irp->MdlAddress)
 		return STATUS_INVALID_PARAMETER;
 	ULONG size_mdl;
+	*buffer = NULL;
 	NdisQueryMdl(Irp->MdlAddress, buffer, &size_mdl, priority);
-	if (!buffer)
+	if (!*buffer)
 		return STATUS_INSUFFICIENT_RESOURCES;
 	if (size_mdl < *size)
 		*size = size_mdl;