From f6ec1dd34fb6b9757b5ead465ee2ea20c182b0ac Mon Sep 17 00:00:00 2001
From: Guomin Jiang <guomin.jiang@intel.com>
Date: Wed, 13 Jan 2021 18:08:09 +0800
Subject: [PATCH] UefiCpuPkg: Move MigrateGdt from DiscoverMemory to
 TempRamDone. (CVE-2019-11098)

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1614
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3160

The GDT still in flash with commit 60b12e69fb1c8c7180fdda92f008248b9ec83db1
after TempRamDone

So move the action to TempRamDone event to avoid reading GDT from flash.

Signed-off-by: Guomin Jiang <guomin.jiang@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Debkumar De <debkumar.de@intel.com>
Cc: Harry Han <harry.han@intel.com>
Cc: Catharine West <catharine.west@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
---
 UefiCpuPkg/CpuMpPei/CpuMpPei.c   | 37 --------------------------
 UefiCpuPkg/CpuMpPei/CpuMpPei.inf |  1 -
 UefiCpuPkg/CpuMpPei/CpuPaging.c  |  8 ------
 UefiCpuPkg/SecCore/SecCore.inf   |  1 +
 UefiCpuPkg/SecCore/SecMain.c     | 45 ++++++++++++++++++++++++++++++++
 5 files changed, 46 insertions(+), 46 deletions(-)

Index: edk2-edk2-stable201911/UefiCpuPkg/CpuMpPei/CpuMpPei.c
===================================================================
--- edk2-edk2-stable201911.orig/UefiCpuPkg/CpuMpPei/CpuMpPei.c
+++ edk2-edk2-stable201911/UefiCpuPkg/CpuMpPei/CpuMpPei.c
@@ -430,43 +430,6 @@ GetGdtr (
 }
 
 /**
-  Migrates the Global Descriptor Table (GDT) to permanent memory.
-
-  @retval   EFI_SUCCESS           The GDT was migrated successfully.
-  @retval   EFI_OUT_OF_RESOURCES  The GDT could not be migrated due to lack of available memory.
-
-**/
-EFI_STATUS
-MigrateGdt (
-  VOID
-  )
-{
-  EFI_STATUS          Status;
-  UINTN               GdtBufferSize;
-  IA32_DESCRIPTOR     Gdtr;
-  VOID                *GdtBuffer;
-
-  AsmReadGdtr ((IA32_DESCRIPTOR *) &Gdtr);
-  GdtBufferSize = sizeof (IA32_SEGMENT_DESCRIPTOR) -1 + Gdtr.Limit + 1;
-
-  Status =  PeiServicesAllocatePool (
-              GdtBufferSize,
-              &GdtBuffer
-              );
-  ASSERT (GdtBuffer != NULL);
-  if (EFI_ERROR (Status)) {
-    return EFI_OUT_OF_RESOURCES;
-  }
-
-  GdtBuffer = ALIGN_POINTER (GdtBuffer, sizeof (IA32_SEGMENT_DESCRIPTOR));
-  CopyMem (GdtBuffer, (VOID *) Gdtr.Base, Gdtr.Limit + 1);
-  Gdtr.Base = (UINTN) GdtBuffer;
-  AsmWriteGdtr (&Gdtr);
-
-  return EFI_SUCCESS;
-}
-
-/**
   Initializes CPU exceptions handlers for the sake of stack switch requirement.
 
   This function is a wrapper of InitializeCpuExceptionHandlersEx. It's mainly
Index: edk2-edk2-stable201911/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
===================================================================
--- edk2-edk2-stable201911.orig/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
+++ edk2-edk2-stable201911/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
@@ -66,7 +66,6 @@
   gUefiCpuPkgTokenSpaceGuid.PcdCpuStackSwitchExceptionList              ## SOMETIMES_CONSUMES
   gUefiCpuPkgTokenSpaceGuid.PcdCpuKnownGoodStackSize                    ## SOMETIMES_CONSUMES
   gUefiCpuPkgTokenSpaceGuid.PcdCpuApStackSize                           ## SOMETIMES_CONSUMES
-  gEfiMdeModulePkgTokenSpaceGuid.PcdMigrateTemporaryRamFirmwareVolumes  ## CONSUMES
 
 [Depex]
   TRUE
Index: edk2-edk2-stable201911/UefiCpuPkg/CpuMpPei/CpuPaging.c
===================================================================
--- edk2-edk2-stable201911.orig/UefiCpuPkg/CpuMpPei/CpuPaging.c
+++ edk2-edk2-stable201911/UefiCpuPkg/CpuMpPei/CpuPaging.c
@@ -605,17 +605,9 @@ MemoryDiscoveredPpiNotifyCallback (
 {
   EFI_STATUS              Status;
   BOOLEAN                 InitStackGuard;
-  BOOLEAN                 InterruptState;
   EDKII_MIGRATED_FV_INFO  *MigratedFvInfo;
   EFI_PEI_HOB_POINTERS    Hob;
 
-  if (PcdGetBool (PcdMigrateTemporaryRamFirmwareVolumes)) {
-    InterruptState = SaveAndDisableInterrupts ();
-    Status = MigrateGdt ();
-    ASSERT_EFI_ERROR (Status);
-    SetInterruptState (InterruptState);
-  }
-
   //
   // Paging must be setup first. Otherwise the exception TSS setup during MP
   // initialization later will not contain paging information and then fail
Index: edk2-edk2-stable201911/UefiCpuPkg/SecCore/SecCore.inf
===================================================================
--- edk2-edk2-stable201911.orig/UefiCpuPkg/SecCore/SecCore.inf
+++ edk2-edk2-stable201911/UefiCpuPkg/SecCore/SecCore.inf
@@ -77,6 +77,7 @@
 
 [Pcd]
   gUefiCpuPkgTokenSpaceGuid.PcdPeiTemporaryRamStackSize  ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdMigrateTemporaryRamFirmwareVolumes  ## CONSUMES
 
 [UserExtensions.TianoCore."ExtraFiles"]
   SecCoreExtra.uni
Index: edk2-edk2-stable201911/UefiCpuPkg/SecCore/SecMain.c
===================================================================
--- edk2-edk2-stable201911.orig/UefiCpuPkg/SecCore/SecMain.c
+++ edk2-edk2-stable201911/UefiCpuPkg/SecCore/SecMain.c
@@ -35,6 +35,43 @@ EFI_PEI_PPI_DESCRIPTOR            mPeiSe
   }
 };
 
+/**
+  Migrates the Global Descriptor Table (GDT) to permanent memory.
+
+  @retval   EFI_SUCCESS           The GDT was migrated successfully.
+  @retval   EFI_OUT_OF_RESOURCES  The GDT could not be migrated due to lack of available memory.
+
+**/
+EFI_STATUS
+MigrateGdt (
+  VOID
+  )
+{
+  EFI_STATUS          Status;
+  UINTN               GdtBufferSize;
+  IA32_DESCRIPTOR     Gdtr;
+  VOID                *GdtBuffer;
+
+  AsmReadGdtr ((IA32_DESCRIPTOR *) &Gdtr);
+  GdtBufferSize = sizeof (IA32_SEGMENT_DESCRIPTOR) -1 + Gdtr.Limit + 1;
+
+  Status =  PeiServicesAllocatePool (
+              GdtBufferSize,
+              &GdtBuffer
+              );
+  ASSERT (GdtBuffer != NULL);
+  if (EFI_ERROR (Status)) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  GdtBuffer = ALIGN_POINTER (GdtBuffer, sizeof (IA32_SEGMENT_DESCRIPTOR));
+  CopyMem (GdtBuffer, (VOID *) Gdtr.Base, Gdtr.Limit + 1);
+  Gdtr.Base = (UINTN) GdtBuffer;
+  AsmWriteGdtr (&Gdtr);
+
+  return EFI_SUCCESS;
+}
+
 //
 // These are IDT entries pointing to 10:FFFFFFE4h.
 //
@@ -410,6 +447,14 @@ SecTemporaryRamDone (
   State = SaveAndDisableInterrupts ();
 
   //
+  // Migrate GDT before NEM near down
+  //
+  if (PcdGetBool (PcdMigrateTemporaryRamFirmwareVolumes)) {
+    Status = MigrateGdt ();
+    ASSERT_EFI_ERROR (Status);
+  }
+
+  //
   // Disable Temporary RAM after Stack and Heap have been migrated at this point.
   //
   SecPlatformDisableTemporaryMemory ();
