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From: "Guomin Jiang" <guomin.jiang@intel.com>
To: devel@edk2.groups.io
Cc: Eric Dong <eric.dong@intel.com>, Ray Ni <ray.ni@intel.com>,
	Laszlo Ersek <lersek@redhat.com>,
	Rahul Kumar <rahul1.kumar@intel.com>
Subject: [PATCH v4 7/9] UefiCpuPkg/CpuMpPei: Enable paging and set NP flag to avoid TOCTOU (CVE-2019-11098)
Date: Wed,  8 Jul 2020 16:10:57 +0800	[thread overview]
Message-ID: <20200708081059.691-8-guomin.jiang@intel.com> (raw)
In-Reply-To: <20200708081059.691-1-guomin.jiang@intel.com>

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

To avoid the TOCTOU, enable paging and set Not Present flag so when
access any code in the flash range, it will trigger #NP exception.

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>
Signed-off-by: Guomin Jiang <guomin.jiang@intel.com>
---
 UefiCpuPkg/CpuMpPei/CpuMpPei.inf |  3 +++
 UefiCpuPkg/CpuMpPei/CpuPaging.c  | 26 ++++++++++++++++++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
index f4d11b861f77..7e511325d8b8 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.inf
@@ -46,6 +46,9 @@ [LibraryClasses]
   BaseMemoryLib
   CpuLib
 
+[Guids]
+  gEdkiiMigratedFvInfoGuid                                             ## SOMETIMES_CONSUMES     ## HOB
+
 [Ppis]
   gEfiPeiMpServicesPpiGuid                      ## PRODUCES
   gEfiSecPlatformInformationPpiGuid             ## SOMETIMES_CONSUMES
diff --git a/UefiCpuPkg/CpuMpPei/CpuPaging.c b/UefiCpuPkg/CpuMpPei/CpuPaging.c
index 3bf0574b34c6..04a16fb2b620 100644
--- a/UefiCpuPkg/CpuMpPei/CpuPaging.c
+++ b/UefiCpuPkg/CpuMpPei/CpuPaging.c
@@ -12,6 +12,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/MemoryAllocationLib.h>
 #include <Library/CpuLib.h>
 #include <Library/BaseLib.h>
+#include <Guid/MigratedFvInfo.h>
 
 #include "CpuMpPei.h"
 
@@ -605,6 +606,8 @@ MemoryDiscoveredPpiNotifyCallback (
   EFI_STATUS  Status;
   BOOLEAN     InitStackGuard;
   BOOLEAN     InterruptState;
+  EDKII_MIGRATED_FV_INFO *MigratedFvInfo;
+  EFI_PEI_HOB_POINTERS   Hob;
 
   if (PcdGetBool (PcdMigrateTemporaryRamFirmwareVolumes)) {
     InterruptState = SaveAndDisableInterrupts ();
@@ -619,9 +622,14 @@ MemoryDiscoveredPpiNotifyCallback (
   // the task switch (for the sake of stack switch).
   //
   InitStackGuard = FALSE;
-  if (IsIa32PaeSupported () && PcdGetBool (PcdCpuStackGuard)) {
+  Hob.Raw = NULL;
+  if (IsIa32PaeSupported ()) {
+    Hob.Raw  = GetFirstGuidHob (&gEdkiiMigratedFvInfoGuid);
+    InitStackGuard = PcdGetBool (PcdCpuStackGuard);
+  }
+
+  if (InitStackGuard || Hob.Raw != NULL) {
     EnablePaging ();
-    InitStackGuard = TRUE;
   }
 
   Status = InitializeCpuMpWorker ((CONST EFI_PEI_SERVICES **)PeiServices);
@@ -631,6 +639,20 @@ MemoryDiscoveredPpiNotifyCallback (
     SetupStackGuardPage ();
   }
 
+  while (Hob.Raw != NULL) {
+    MigratedFvInfo = GET_GUID_HOB_DATA (Hob);
+
+    //
+    // Enable #NP exception, so if the code access after disable NEM, it will generate
+    // to avoid potential vulnerability.
+    //
+    ConvertMemoryPageAttributes (MigratedFvInfo->FvOrgBase, MigratedFvInfo->FvLength, 0);
+
+    Hob.Raw = GET_NEXT_HOB (Hob);
+    Hob.Raw = GetNextGuidHob (&gEdkiiMigratedFvInfoGuid, Hob.Raw);
+  }
+  CpuFlushTlb ();
+
   return Status;
 }
 
-- 
2.25.1.windows.1


  parent reply	other threads:[~2020-07-08  8:11 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-08  8:10 [PATCH v4 0/9] Add new feature that evacuate temporary to permanent memory (CVE-2019-11098) Guomin Jiang
2020-07-08  8:10 ` [PATCH v4 1/9] MdeModulePkg: Add new PCD to control the evacuate temporary memory feature (CVE-2019-11098) Guomin Jiang
2020-07-08 17:03   ` [edk2-devel] " Laszlo Ersek
2020-07-08  8:10 ` [PATCH v4 2/9] MdeModulePkg/PeiCore: Enable T-RAM evacuation in PeiCore (CVE-2019-11098) Guomin Jiang
2020-07-08 17:13   ` [edk2-devel] " Laszlo Ersek
2020-07-08  8:10 ` [PATCH v4 3/9] UefiCpuPkg/CpuMpPei: Add GDT and IDT migration support (CVE-2019-11098) Guomin Jiang
2020-07-08 17:23   ` [edk2-devel] " Laszlo Ersek
2020-07-08  8:10 ` [PATCH v4 4/9] UefiCpuPkg/SecMigrationPei: Add initial PEIM (CVE-2019-11098) Guomin Jiang
2020-07-08 17:35   ` [edk2-devel] " Laszlo Ersek
2020-07-08  8:10 ` [PATCH v4 5/9] MdeModulePkg/Core: Create Migrated FV Info Hob for calculating hash (CVE-2019-11098) Guomin Jiang
2020-07-08 17:29   ` [edk2-devel] " Laszlo Ersek
2020-07-08  8:10 ` [PATCH v4 6/9] SecurityPkg/Tcg2Pei: Use " Guomin Jiang
2020-07-08  8:10 ` Guomin Jiang [this message]
2020-07-08 17:54   ` [edk2-devel] [PATCH v4 7/9] UefiCpuPkg/CpuMpPei: Enable paging and set NP flag to avoid TOCTOU (CVE-2019-11098) Laszlo Ersek
2020-07-08  8:10 ` [PATCH v4 8/9] UefiCpuPkg: Correct some typos Guomin Jiang
2020-07-08 18:02   ` [edk2-devel] " Laszlo Ersek
2020-07-08  8:10 ` [PATCH v4 9/9] SecurityPkg/TcgPei: Use Migrated FV Info Hob for calculating hash (CVE-2019-11098) Guomin Jiang

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