REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2594
Provide function that retrieves the key for protected
variables.
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
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>
---
SecurityPkg/Library/VariableKeyLib/VariableKeyLib.inf | 36 ++++++++++++
SecurityPkg/Library/VariableKeyLib/VariableKeyLib.c | 59 ++++++++++++++++++++
2 files changed, 95 insertions(+)
diff --git a/SecurityPkg/Library/VariableKeyLib/VariableKeyLib.inf b/SecurityPkg/Library/VariableKeyLib/VariableKeyLib.inf
new file mode 100644
index 000000000000..f62c80ce9943
--- /dev/null
+++ b/SecurityPkg/Library/VariableKeyLib/VariableKeyLib.inf
@@ -0,0 +1,36 @@
+## @file
+# Provides default implementation of VariableKeyLib.
+#
+# Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+ INF_VERSION = 0x00010029
+ BASE_NAME = VariableKeyLib
+ FILE_GUID = 7DF5A0BA-1DBB-4E67-A9F7-9FCCB1F9D250
+ MODULE_TYPE = BASE
+ VERSION_STRING = 1.0
+ LIBRARY_CLASS = VariableKeyLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+# VALID_ARCHITECTURES = IA32 X64 Arm AArch64
+#
+
+[Sources]
+ VariableKeyLib.c
+
+[Packages]
+ MdePkg/MdePkg.dec
+ SecurityPkg/SecurityPkg.dec
+
+[LibraryClasses]
+ BaseLib
+ DebugLib
+
+[PpiS]
+ gKeyServicePpiGuid ## CONSUMES
+
diff --git a/SecurityPkg/Library/VariableKeyLib/VariableKeyLib.c b/SecurityPkg/Library/VariableKeyLib/VariableKeyLib.c
new file mode 100644
index 000000000000..31b22782cb0c
--- /dev/null
+++ b/SecurityPkg/Library/VariableKeyLib/VariableKeyLib.c
@@ -0,0 +1,59 @@
+/** @file
+ VariableKeyLib implementation.
+
+Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <PiPei.h>
+
+#include <Library/PeiServicesLib.h>
+#include <Library/DebugLib.h>
+#include <Library/VariableKeyLib.h>
+
+#include <Ppi/KeyServicePpi.h>
+
+#define VAR_KEY_SALT L"Key for RPMC Variable"
+#define VAR_KEY_SALT_SIZE sizeof (VAR_KEY_SALT)
+
+/**
+ Retrieves the key for integrity and/or confidentiality of variables.
+
+ @param[out] VariableKey A pointer to pointer for the variable key buffer.
+ @param[in] VariableKeySize The size in bytes of the variable key.
+
+ @retval EFI_SUCCESS The variable key was returned.
+ @retval EFI_DEVICE_ERROR An error occurred while attempting to get the variable key.
+ @retval EFI_ACCESS_DENIED The function was invoked after locking the key interface.
+ @retval EFI_UNSUPPORTED The variable key is not supported in the current boot configuration.
+**/
+EFI_STATUS
+EFIAPI
+GetVariableKey (
+ OUT VOID *VariableKey,
+ IN UINTN VariableKeySize
+ )
+{
+ EFI_STATUS Status;
+ KEY_SERVICE_PPI *KeyService;
+
+ Status = PeiServicesLocatePpi (
+ &gKeyServicePpiGuid,
+ 0,
+ NULL,
+ (void **)&KeyService
+ );
+ if (EFI_ERROR (Status)) {
+ ASSERT_EFI_ERROR (Status);
+ return Status;
+ }
+
+ Status = KeyService->GenerateKey (
+ (UINT8 *)VAR_KEY_SALT,
+ VAR_KEY_SALT_SIZE,
+ VariableKey,
+ VariableKeySize
+ );
+ return Status;
+}
--
2.35.1.windows.2
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