Add boundary check against variable MTRR count.

[mirror_edk2.git] / UefiCpuPkg / Library / MtrrLib / MtrrLib.c

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index 1f2604ab8b9fecd5a4f6ed1be92e187d2882be49..fca9258ed7aef8142f484813969c8fd433a9f841 100644 (file)
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -93,11 +93,16 @@ GetVariableMtrrCount (
   VOID\r
   )\r
 {\r
+  UINT32  VariableMtrrCount;\r
+\r
   if (!IsMtrrSupported ()) {\r
     return 0;\r
   }\r
 \r
-  return (UINT32)(AsmReadMsr64 (MTRR_LIB_IA32_MTRR_CAP) & MTRR_LIB_IA32_MTRR_CAP_VCNT_MASK);\r
+  VariableMtrrCount = (UINT32)(AsmReadMsr64 (MTRR_LIB_IA32_MTRR_CAP) & MTRR_LIB_IA32_MTRR_CAP_VCNT_MASK);\r
+  ASSERT (VariableMtrrCount <= MTRR_NUMBER_OF_VARIABLE_MTRR);\r
+\r
+  return VariableMtrrCount;\r
 }\r
 \r
 /**\r