From d6f38e374ece00f1f8176007c9d3e8eff1f2308f Mon Sep 17 00:00:00 2001
From: Star Zeng <star.zeng@intel.com>
Date: Sun, 12 Jun 2016 12:45:09 +0800
Subject: [PATCH] MdeModulePkg DxeS3BootScriptLib: Check (mSmst != NULL) before
 freeing SMRAM

There is static scan tool reports BootScriptSave.c:628:'mSmst' is
explicitly dereferenced.

The patch is to check (mSmst != NULL) before freeing SMRAM at
BootScriptSave.c:628.

Cc: Shumin Qiu <shumin.qiu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Shumin Qiu <shumin.qiu@intel.com>
---
 MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c b/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
index f6de986e08..0ff73211ac 100644
--- a/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
+++ b/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
@@ -624,7 +624,7 @@ S3BootScriptLibDeinitialize (
     Status = PcdSet64S (PcdS3BootScriptTablePrivateDataPtr, 0);
     ASSERT_EFI_ERROR (Status);
   }
-  if (mS3BootScriptTableSmmAllocated) {
+  if ((mSmst != NULL) && mS3BootScriptTableSmmAllocated) {
     Status = mSmst->SmmFreePool (mS3BootScriptTableSmmPtr);
     ASSERT_EFI_ERROR (Status);
     Status = PcdSet64S (PcdS3BootScriptTablePrivateSmmDataPtr, 0);