Re: [edk2-devel] [Patch V6 02/14] MdeModulePkg: Remove other attribute protection in UnsetGuardPage

["duntan" <dun.tan@intel.com>]

Hi all,

Could you please help to review this patch?

Thanks,
Dun

-----Original Message-----
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of duntan
Sent: Friday, June 9, 2023 5:16 PM
To: devel@edk2.groups.io
Cc: Gao, Liming <gaoliming@byosoft.com.cn>; Ni, Ray <ray.ni@intel.com>; Wang, Jian J <jian.j.wang@intel.com>; Ard Biesheuvel <ardb+tianocore@kernel.org>
Subject: [edk2-devel] [Patch V6 02/14] 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>
Cc: 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;
   }
 }
--
2.31.1.windows.1