[PATCH 1/2] MdePkg/SmmMemLib: Avoid possible NULL ptr dereference

[Hao Wu <hao.a.wu@intel.com>]

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

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

diff --git a/MdePkg/Library/SmmMemLib/SmmMemLib.c b/MdePkg/Library/SmmMemLib/SmmMemLib.c
index 3409ddf87c..3e458417de 100644
--- a/MdePkg/Library/SmmMemLib/SmmMemLib.c
+++ b/MdePkg/Library/SmmMemLib/SmmMemLib.c
@@ -439,7 +439,7 @@ SmmMemLibInternalGetUefiMemoryAttributesTable (
   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;
     mSmmMemLibMemoryAttributesTable = AllocateCopyPool (MemoryAttributesTableSize, MemoryAttributesTable);
     ASSERT (mSmmMemLibMemoryAttributesTable != NULL);
-- 
2.12.0.windows.1