[PATCH v1 2/5] MdeModulePkg: PiSmmIpl: Update MessageLength calculation for MmCommunicate

["Kun Qin" <kuqin12@gmail.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3398

This change updated calculation routine for MM communication in PiSmmIpl.
It removes ambiguity brought in by UINTN variables from this routine and
paves way for updating definition of field MessageLength in
EFI_MM_COMMUNICATE_HEADER to definitive size.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>

Signed-off-by: Kun Qin <kuqin12@gmail.com>
---
 MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c   | 13 ++++++++++++-
 MdeModulePkg/Core/PiSmmCore/PiSmmIpl.inf |  1 +
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c b/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c
index 599a0cd01d80..9508715fda24 100644
--- a/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c
+++ b/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c
@@ -34,6 +34,7 @@
 #include <Library/UefiRuntimeLib.h>
 #include <Library/PcdLib.h>
 #include <Library/ReportStatusCodeLib.h>
+#include <Library/SafeIntLib.h> // BZ3398
 
 #include "PiSmmCorePrivateData.h"
 
@@ -515,6 +516,7 @@ SmmCommunicationCommunicate (
   EFI_STATUS                  Status;
   EFI_SMM_COMMUNICATE_HEADER  *CommunicateHeader;
   BOOLEAN                     OldInSmm;
+  UINT64                      BZ3398_LongCommSize;
   UINTN                       TempCommSize;
 
   //
@@ -527,7 +529,16 @@ SmmCommunicationCommunicate (
   CommunicateHeader = (EFI_SMM_COMMUNICATE_HEADER *) CommBuffer;
 
   if (CommSize == NULL) {
-    TempCommSize = OFFSET_OF (EFI_SMM_COMMUNICATE_HEADER, Data) + CommunicateHeader->MessageLength;
+    // BZ3398 Starts: Make MessageLength the same size in EFI_MM_COMMUNICATE_HEADER for both IA32 and X64.
+    Status = SafeUint64Add (OFFSET_OF (EFI_SMM_COMMUNICATE_HEADER, Data), CommunicateHeader->MessageLength, &BZ3398_LongCommSize);
+    if (EFI_ERROR (Status)) {
+      return EFI_INVALID_PARAMETER;
+    }
+    Status = SafeUint64ToUintn (BZ3398_LongCommSize, &TempCommSize);
+    if (EFI_ERROR (Status)) {
+      return EFI_INVALID_PARAMETER;
+    }
+    // BZ3398 Ends
   } else {
     TempCommSize = *CommSize;
     //
diff --git a/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.inf b/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.inf
index 6109d6b5449c..87142e27fa47 100644
--- a/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.inf
+++ b/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.inf
@@ -46,6 +46,7 @@ [LibraryClasses]
   DxeServicesLib
   PcdLib
   ReportStatusCodeLib
+  SafeIntLib  #BZ3398
 
 [Protocols]
   gEfiSmmBase2ProtocolGuid                      ## PRODUCES
-- 
2.31.1.windows.1