From a48caeebbab99e22bfd4072829ecaf553cc92c9c Mon Sep 17 00:00:00 2001
From: xli24 <xli24@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Tue, 10 Aug 2010 08:57:36 +0000
Subject: [PATCH] Add boundary check against variable MTRR count.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10787 6f19259b-4bc3-4df7-8a09-765794883524
---
 UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index 1f2604ab8b..fca9258ed7 100644
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -93,11 +93,16 @@ GetVariableMtrrCount (
   VOID
   )
 {
+  UINT32  VariableMtrrCount;
+
   if (!IsMtrrSupported ()) {
     return 0;
   }
 
-  return (UINT32)(AsmReadMsr64 (MTRR_LIB_IA32_MTRR_CAP) & MTRR_LIB_IA32_MTRR_CAP_VCNT_MASK);
+  VariableMtrrCount = (UINT32)(AsmReadMsr64 (MTRR_LIB_IA32_MTRR_CAP) & MTRR_LIB_IA32_MTRR_CAP_VCNT_MASK);
+  ASSERT (VariableMtrrCount <= MTRR_NUMBER_OF_VARIABLE_MTRR);
+
+  return VariableMtrrCount;
 }
 
 /**