From 8c9983977676d68466c770846d3e64470b3d8668 Mon Sep 17 00:00:00 2001
From: Dun Tan <dun.tan@intel.com>
Date: Tue, 16 May 2023 15:51:50 +0800
Subject: [PATCH] MdeModulePkg: Remove other attribute protection in
 UnsetGuardPage

In UnsetGuardPage(), before SmmReadyToLock, remove NX and RO
memory attribute protection for guarded page since
EfiConventionalMemory in SMRAM is RW and executable before
SmmReadyToLock. If UnsetGuardPage() happens after SmmReadyToLock,
then apply EFI_MEMORY_XP to the guarded page to make sure
EfiConventionalMemory in SMRAM is NX since EfiConventionalMemory
in SMRAM is marked as NX in PiSmmCpuDxe driver when SmmReadyToLock.

Signed-off-by: Dun Tan <dun.tan@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Ray Ni <ray.ni@intel.com>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
---
 MdeModulePkg/Core/PiSmmCore/HeapGuard.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Core/PiSmmCore/HeapGuard.c b/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
index 8f3bab6fee..25310122ca 100644
--- a/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
+++ b/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
@@ -553,9 +553,23 @@ UnsetGuardPage (
                                          mSmmMemoryAttribute,
                                          BaseAddress,
                                          EFI_PAGE_SIZE,
-                                         EFI_MEMORY_RP
+                                         EFI_MEMORY_RP|EFI_MEMORY_RO|EFI_MEMORY_XP
                                          );
     ASSERT_EFI_ERROR (Status);
+
+    if (gST == NULL) {
+      //
+      // Make sure EfiConventionalMemory is NX after SmmReadyToLock
+      //
+      Status = mSmmMemoryAttribute->SetMemoryAttributes (
+                                      mSmmMemoryAttribute,
+                                      BaseAddress,
+                                      EFI_PAGE_SIZE,
+                                      EFI_MEMORY_XP
+                                      );
+      ASSERT_EFI_ERROR (Status);
+    }
+
     mOnGuarding = FALSE;
   }
 }