[PATCH v2 02/11] SecurityPkg: PlatformPKProtectionLib: Added PK protection interface

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

From: Kun Qin <kuqin@microsoft.com>

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3911

This patch provides an abstracted interface for platform to implement PK
variable related protection interface, which is designed to be used when
PK variable is about to be changed by UEFI firmware.

This change also provided a variable policy based library implementation
to accomodate platforms that supports variable policy for variable
protections.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Min Xu <min.m.xu@intel.com>

Signed-off-by: Kun Qin <kun.qin@microsoft.com>
---
 SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.c   | 51 ++++++++++++++++++++
 SecurityPkg/Include/Library/PlatformPKProtectionLib.h                                     | 31 ++++++++++++
 SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.inf | 36 ++++++++++++++
 SecurityPkg/SecurityPkg.dec                                                               |  5 ++
 SecurityPkg/SecurityPkg.dsc                                                               |  2 +
 5 files changed, 125 insertions(+)

diff --git a/SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.c b/SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.c
new file mode 100644
index 000000000000..a2649242246f
--- /dev/null
+++ b/SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.c
@@ -0,0 +1,51 @@
+/** @file
+  Provides an abstracted interface for configuring PK related variable protection.
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+#include <Uefi.h>
+#include <Protocol/VariablePolicy.h>
+
+#include <Library/DebugLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+
+/**
+  Disable any applicable protection against variable 'PK'. The implementation
+  of this interface is platform specific, depending on the protection techniques
+  used per platform.
+
+  Note: It is the platform's responsibility to conduct cautious operation after
+        disabling this protection.
+
+  @retval     EFI_SUCCESS             State has been successfully updated.
+  @retval     Others                  Error returned from implementation specific
+                                      underying APIs.
+
+**/
+EFI_STATUS
+EFIAPI
+DisablePKProtection (
+  VOID
+  )
+{
+  EFI_STATUS                      Status;
+  EDKII_VARIABLE_POLICY_PROTOCOL  *VariablePolicy;
+
+  DEBUG ((DEBUG_INFO, "%a() Entry...\n", __FUNCTION__));
+
+  // IMPORTANT NOTE: This operation is sticky and leaves variable protections disabled.
+  //                  The system *MUST* be reset after performing this operation.
+  Status = gBS->LocateProtocol (&gEdkiiVariablePolicyProtocolGuid, NULL, (VOID **)&VariablePolicy);
+  if (!EFI_ERROR (Status)) {
+    Status = VariablePolicy->DisableVariablePolicy ();
+    // EFI_ALREADY_STARTED means that everything is currently disabled.
+    // This should be considered SUCCESS.
+    if (Status == EFI_ALREADY_STARTED) {
+      Status = EFI_SUCCESS;
+    }
+  }
+
+  return Status;
+}
diff --git a/SecurityPkg/Include/Library/PlatformPKProtectionLib.h b/SecurityPkg/Include/Library/PlatformPKProtectionLib.h
new file mode 100644
index 000000000000..3586a47b77c2
--- /dev/null
+++ b/SecurityPkg/Include/Library/PlatformPKProtectionLib.h
@@ -0,0 +1,31 @@
+/** @file
+  Provides an abstracted interface for configuring PK related variable protection.
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef PLATFORM_PK_PROTECTION_LIB_H_
+#define PLATFORM_PK_PROTECTION_LIB_H_
+
+/**
+  Disable any applicable protection against variable 'PK'. The implementation
+  of this interface is platform specific, depending on the protection techniques
+  used per platform.
+
+  Note: It is the platform's responsibility to conduct cautious operation after
+        disabling this protection.
+
+  @retval     EFI_SUCCESS             State has been successfully updated.
+  @retval     Others                  Error returned from implementation specific
+                                      underying APIs.
+
+**/
+EFI_STATUS
+EFIAPI
+DisablePKProtection (
+  VOID
+  );
+
+#endif
diff --git a/SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.inf b/SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.inf
new file mode 100644
index 000000000000..df42ce06c019
--- /dev/null
+++ b/SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.inf
@@ -0,0 +1,36 @@
+## @file
+#  Provides an abstracted interface for configuring PK related variable protection.
+#
+#  Copyright (c) Microsoft Corporation.
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = PlatformPKProtectionLibVarPolicy
+  FILE_GUID                      = AE0C5992-526C-4518-93BA-3C2611B801E0
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = PlatformPKProtectionLib|DXE_DRIVER DXE_RUNTIME_DRIVER UEFI_APPLICATION
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
+#
+
+[Sources]
+  PlatformPKProtectionLibVarPolicy.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  SecurityPkg/SecurityPkg.dec
+
+[LibraryClasses]
+  DebugLib
+  UefiBootServicesTableLib
+
+[Protocols]
+  gEdkiiVariablePolicyProtocolGuid
diff --git a/SecurityPkg/SecurityPkg.dec b/SecurityPkg/SecurityPkg.dec
index 0ee75efc1a97..7ecf9565d98c 100644
--- a/SecurityPkg/SecurityPkg.dec
+++ b/SecurityPkg/SecurityPkg.dec
@@ -99,6 +99,11 @@ [LibraryClasses]
   ## @libraryclass  Provides support to enroll Secure Boot keys.
   #
   SecureBootVariableProvisionLib|Include/Library/SecureBootVariableProvisionLib.h
+
+  ## @libraryclass  Provides support to manage variable 'PK' related protections.
+  #
+  PlatformPKProtectionLib|Include/Library/PlatformPKProtectionLib.h
+
 [Guids]
   ## Security package token space guid.
   # Include/Guid/SecurityPkgTokenSpace.h
diff --git a/SecurityPkg/SecurityPkg.dsc b/SecurityPkg/SecurityPkg.dsc
index d883747474e4..f48187650f2f 100644
--- a/SecurityPkg/SecurityPkg.dsc
+++ b/SecurityPkg/SecurityPkg.dsc
@@ -71,6 +71,7 @@ [LibraryClasses]
   TcgEventLogRecordLib|SecurityPkg/Library/TcgEventLogRecordLib/TcgEventLogRecordLib.inf
   MmUnblockMemoryLib|MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.inf
   SecureBootVariableLib|SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.inf
+  PlatformPKProtectionLib|SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.inf
   SecureBootVariableProvisionLib|SecurityPkg/Library/SecureBootVariableProvisionLib/SecureBootVariableProvisionLib.inf
   TdxLib|MdePkg/Library/TdxLib/TdxLib.inf
 
@@ -261,6 +262,7 @@ [Components]
   #
   SecurityPkg/Library/VariableKeyLibNull/VariableKeyLibNull.inf
   SecurityPkg/Library/RpmcLibNull/RpmcLibNull.inf
+  SecurityPkg/Library/PlatformPKProtectionLibVarPolicy/PlatformPKProtectionLibVarPolicy.inf
 
   #
   # Other
-- 
2.35.1.windows.2