[win-pv-devel] [PATCH] Fix BSOD on shutdown due to freeing NULL pointer

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

Unfortunately ExFreePoolWithTag() is not NULL-safe, and Base64Free() is
coded assuming it is. This patch adds an extra check for NULL to fix the
problem.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
 src/xenvbd/base64.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/xenvbd/base64.c b/src/xenvbd/base64.c
index 3e79b9f..0e62784 100644
--- a/src/xenvbd/base64.c
+++ b/src/xenvbd/base64.c
@@ -60,7 +60,8 @@ Base64Free(
     IN  PVOID   Buffer
     )
 {
-    ExFreePoolWithTag(Buffer, BASE64_POOL_TAG);
+    if (Buffer)
+        ExFreePoolWithTag(Buffer, BASE64_POOL_TAG);
 }
 
 static FORCEINLINE UCHAR
-- 
2.5.3


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