From 6d9a0a9420167a87d353b53b93fec17ad61b4b61 Mon Sep 17 00:00:00 2001
From: Hao Wu <hao.a.wu@intel.com>
Date: Mon, 30 Jul 2018 13:20:13 +0800
Subject: [PATCH] UefiCpuPkg/PiSmmCpuDxeSmm: Avoid possible NULL ptr
 dereference

Within function GetUefiMemoryAttributesTable(), add a check to avoid
possible null pointer dereference.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
 UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
index 7d99f23426..684b14dc28 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
@@ -1098,7 +1098,7 @@ GetUefiMemoryAttributesTable (
   UINTN                        MemoryAttributesTableSize;
 
   Status = EfiGetSystemConfigurationTable (&gEfiMemoryAttributesTableGuid, (VOID **)&MemoryAttributesTable);
-  if (!EFI_ERROR (Status)) {
+  if (!EFI_ERROR (Status) && (MemoryAttributesTable != NULL)) {
     MemoryAttributesTableSize = sizeof(EFI_MEMORY_ATTRIBUTES_TABLE) + MemoryAttributesTable->DescriptorSize * MemoryAttributesTable->NumberOfEntries;
     mUefiMemoryAttributesTable = AllocateCopyPool (MemoryAttributesTableSize, MemoryAttributesTable);
     ASSERT (mUefiMemoryAttributesTable != NULL);