[PATCH v4 06/28] MdeModulePkg: Add Null ProtectedVariable Library

["Judah Vang" <judah.vang@intel.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2594

V4: Applied code review comments - removed APIs that are not being
used.

V1: Add Null versions of the ProtectedVariable Library.
This will be the default libraries for platforms that
do not support ProtectedVariable.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Nishant C Mistry <nishant.c.mistry@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Signed-off-by: Nishant C Mistry <nishant.c.mistry@intel.com>
Signed-off-by: Judah Vang <judah.vang@intel.com>
---
 MdeModulePkg/Library/ProtectedVariableLibNull/ProtectedVariableLibNull.inf |  34 ++
 MdeModulePkg/Library/ProtectedVariableLibNull/ProtectedVariable.c          | 336 ++++++++++++++++++++
 2 files changed, 370 insertions(+)

diff --git a/MdeModulePkg/Library/ProtectedVariableLibNull/ProtectedVariableLibNull.inf b/MdeModulePkg/Library/ProtectedVariableLibNull/ProtectedVariableLibNull.inf
new file mode 100644
index 000000000000..6a17191c4e1e
--- /dev/null
+++ b/MdeModulePkg/Library/ProtectedVariableLibNull/ProtectedVariableLibNull.inf
@@ -0,0 +1,34 @@
+## @file
+#  Provides null version of protected variable services.
+#
+#  Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010029
+  BASE_NAME                      = ProtectedVariableLibNull
+  FILE_GUID                      = 352C6A1B-403A-4E37-8517-FAA50BC45251
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 0.1
+  LIBRARY_CLASS                  = ProtectedVariableLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64
+#
+
+[Sources]
+  ProtectedVariable.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  BaseMemoryLib
+  DebugLib
+
diff --git a/MdeModulePkg/Library/ProtectedVariableLibNull/ProtectedVariable.c b/MdeModulePkg/Library/ProtectedVariableLibNull/ProtectedVariable.c
new file mode 100644
index 000000000000..074559f84f52
--- /dev/null
+++ b/MdeModulePkg/Library/ProtectedVariableLibNull/ProtectedVariable.c
@@ -0,0 +1,336 @@
+/** @file
+  NULL version of ProtectedVariableLib used to disable protected variable services.
+
+Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <PiDxe.h>
+#include <Uefi.h>
+
+#include <Library/DebugLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/ProtectedVariableLib.h>
+
+/**
+
+  Initialization for protected varibale services.
+
+  @param[in]  ContextIn   Pointer to variable service context needed by
+                          protected variable.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibInitialize (
+  IN  PROTECTED_VARIABLE_CONTEXT_IN  *ContextIn
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Prepare for variable update.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibWriteInit (
+  VOID
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Update a variable with protection provided by this library.
+
+  @param[in,out]  CurrVariable        Variable to be updated. It's NULL if
+                                      adding a new variable.
+  @param[in]      CurrVariableInDel   In-delete-transiion copy of updating variable.
+  @param[in,out]  NewVariable         Buffer of new variable data.
+                                      Buffer of "MetaDataHmacVar" and new
+                                      variable (encrypted).
+  @param[in,out]  NewVariableSize     Size of NewVariable.
+                                      Size of (encrypted) NewVariable and
+                                      "MetaDataHmacVar".
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibUpdate (
+  IN  OUT VARIABLE_HEADER  *CurrVariable,
+  IN      VARIABLE_HEADER  *CurrVariableInDel,
+  IN  OUT VARIABLE_HEADER  *NewVariable,
+  IN  OUT UINTN            *NewVariableSize
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Finalize a variable updating after it's written to NV variable storage
+  successfully.
+
+  @param[in]      NewVariable       Buffer of new variables and MetaDataHmacVar.
+  @param[in]      VariableSize      Size of buffer pointed by NewVariable.
+  @param[in]      StoreIndex        New index of the variable in store.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibWriteFinal (
+  IN  VARIABLE_HEADER  *NewVariable,
+  IN  UINTN            VariableSize,
+  IN  UINT64           StoreIndex
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Retrieve plain data, if encrypted, of given variable.
+
+  @param[in]      Variable           Pointer to header of a Variable.
+  @param[in,out]  Data               Pointer to plain data of the given variable.
+  @param[in,out]  DataSize           Size of data returned or data buffer needed.
+  @param[in]      AuthFlag           Auth-variable indicator.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibGetData (
+  IN      VARIABLE_HEADER  *Variable,
+  IN  OUT VOID             *Data,
+  IN  OUT UINT32           *DataSize,
+  IN      BOOLEAN          AuthFlag
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Get the specified protected variable.
+
+  @param[in]      VariableName      Pointer to variable name.
+  @param[in]      VariableGuid      Pointer to vairable GUID.
+  @param[out]     Attributes        Pointer to attributes.
+  @param[in,out]  DataSize          Pointer to data size.
+  @param[out]     Data              Pointer to data.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibGet (
+  IN      CONST  CHAR16    *VariableName,
+  IN      CONST  EFI_GUID  *VariableGuid,
+  OUT UINT32               *Attributes,
+  IN  OUT UINTN            *DataSize,
+  OUT VOID                 *Data OPTIONAL
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Find the protected variable.
+
+  @param[in,out]      VarInfo     Pointer to structure containing variable information.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibFind (
+  IN  OUT PROTECTED_VARIABLE_INFO  *VarInfo
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Find next protected variable.
+
+  @param[in,out]      VariableNameSize    Pointer to size of variable name.
+  @param[in,out]      VariableName        Pointer to variable name.
+  @param[in,out]      VariableGuid        Pointer to vairable GUID.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibFindNext (
+  IN OUT UINTN     *VariableNameSize,
+  IN OUT CHAR16    *VariableName,
+  IN OUT EFI_GUID  *VariableGuid
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Find next protected variable stub.
+
+  @param[in,out]      VarInfo     Pointer to structure containing variable information.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibFindNextEx (
+  IN  OUT PROTECTED_VARIABLE_INFO  *VarInfo
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Get protected variable by information.
+
+  @param[in,out]      VarInfo     Pointer to structure containing variable information.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibGetByInfo (
+  IN  OUT PROTECTED_VARIABLE_INFO  *VarInfo
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Get protected variable by name.
+
+  @param[in]      VariableName      Pointer to variable name.
+  @param[in]      VariableGuid      Pointer to vairable GUID.
+  @param[out]     Attributes        Pointer to attributes.
+  @param[in,out]  DataSize          Pointer to data size.
+  @param[out]     Data              Pointer to data.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibGetByName (
+  IN      CONST  CHAR16    *VariableName,
+  IN      CONST  EFI_GUID  *VariableGuid,
+  OUT UINT32               *Attributes,
+  IN  OUT UINTN            *DataSize,
+  OUT VOID                 *Data OPTIONAL
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Get protected variable by name.
+
+  @param[in]      Variable      Pointer to variable name.
+  @param[in,out]  Data          Pointer to variable data.
+  @param[in,out]  DataSize      Pointer to data size.
+  @param[in]      AuthFlag      Authenticate flag.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibGetByBuffer (
+  IN      VARIABLE_HEADER  *Variable,
+  IN  OUT VOID             *Data,
+  IN  OUT UINT32           *DataSize,
+  IN      BOOLEAN          AuthFlag
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+  Refresh variable information changed by variable service.
+
+  @param[in]  Variable         Pointer to buffer of the updated variable.
+  @param[in]  VariableSize     Size of variable pointed by Variable.
+  @param[in]  StoreIndex       New index of the variable in store.
+  @param[in]  RefreshData      Flag to indicate if the variable has been updated.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibRefresh (
+  IN  VARIABLE_HEADER  *Variable,
+  IN  UINTN            VariableSize,
+  IN  UINT64           StoreIndex,
+  IN  BOOLEAN          RefreshData
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Get sorted protected variable list.
+
+  @param[in,out]  Buffer        Pointer to buffer.
+  @param[in,out]  NumElements   Pointer to number of elements.
+
+  @retval EFI_UNSUPPORTED           Unsupported to process protected variable.
+
+**/
+EFI_STATUS
+EFIAPI
+ProtectedVariableLibGetSortedList (
+  IN  OUT  EFI_PHYSICAL_ADDRESS  **Buffer,
+  IN  OUT  UINTN                 *NumElements
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+/**
+
+  Determine if the variable is the HMAC variable.
+
+  @param[in]  VariableName   Pointer to variable name.
+
+  @return FALSE     Variable is not HMAC variable
+
+**/
+BOOLEAN
+ProtectedVariableLibIsHmac (
+  IN CHAR16  *VariableName
+  )
+{
+  return FALSE;
+}
-- 
2.35.1.windows.2