From: Hao Wu <hao.a.wu@intel.com>
Date: Mon, 30 Jul 2018 05:17:31 +0000 (+0800)
Subject: MdePkg/SmmMemLib: Avoid possible NULL ptr dereference
X-Git-Tag: edk2-stable201903~1316
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=264914a512f06916aae0e5c292d1f9676ddbbb3d;p=mirror_edk2.git

MdePkg/SmmMemLib: Avoid possible NULL ptr dereference

Within function SmmMemLibInternalGetUefiMemoryAttributesTable(), 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>
---

diff --git a/MdePkg/Library/SmmMemLib/SmmMemLib.c b/MdePkg/Library/SmmMemLib/SmmMemLib.c
index 3409ddf87c..3987af1eba 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);