[edk2-devel] [PATCH v2 04/11] OvmfPkg: add library class BlobVerifierLib with null implementation

[Dov Murik]

BlobVerifierLib will be used to verify blobs fetching them from QEMU's
firmware config (fw_cfg) in platforms that enable such verification.

The null implementation NullBlobVerifierLib treats all blobs as valid.

Cc: Laszlo Ersek <lersek at redhat.com>
Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
Cc: Jordan Justen <jordan.l.justen at intel.com>
Cc: Ashish Kalra <ashish.kalra at amd.com>
Cc: Brijesh Singh <brijesh.singh at amd.com>
Cc: Erdem Aktas <erdemaktas at google.com>
Cc: James Bottomley <jejb at linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao at intel.com>
Cc: Min Xu <min.m.xu at intel.com>
Cc: Tom Lendacky <thomas.lendacky at amd.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3457
Signed-off-by: Dov Murik <dovmurik at linux.ibm.com>
---
 OvmfPkg/OvmfPkg.dec                                     |  3 ++
 OvmfPkg/Library/BlobVerifierLib/NullBlobVerifierLib.inf | 27 ++++++++++++++
 OvmfPkg/Include/Library/BlobVerifierLib.h               | 38 ++++++++++++++++++++
 OvmfPkg/Library/BlobVerifierLib/NullBlobVerifier.c      | 34 ++++++++++++++++++
 4 files changed, 102 insertions(+)

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 6ae733f6e39f..f82228d69cc2 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -23,6 +23,9 @@ [LibraryClasses]
   ##  @libraryclass  Access bhyve's firmware control interface.
   BhyveFwCtlLib|Include/Library/BhyveFwCtlLib.h
 
+  ##  @libraryclass  Verify blobs read from the VMM
+  BlobVerifierLib|Include/Library/BlobVerifierLib.h
+
   ##  @libraryclass  Loads and boots a Linux kernel image
   #
   LoadLinuxLib|Include/Library/LoadLinuxLib.h
diff --git a/OvmfPkg/Library/BlobVerifierLib/NullBlobVerifierLib.inf b/OvmfPkg/Library/BlobVerifierLib/NullBlobVerifierLib.inf
new file mode 100644
index 000000000000..c8942ad05d96
--- /dev/null
+++ b/OvmfPkg/Library/BlobVerifierLib/NullBlobVerifierLib.inf
@@ -0,0 +1,27 @@
+## @file
+#
+#  Null implementation of the blob verifier library.
+#
+#  Copyright (C) 2021, IBM Corp
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = NullBlobVerifierLib
+  FILE_GUID                      = b1b5533e-e01a-43bb-9e54-414f00ca036e
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = BlobVerifierLib
+
+[Sources]
+  NullBlobVerifier.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  DebugLib
diff --git a/OvmfPkg/Include/Library/BlobVerifierLib.h b/OvmfPkg/Include/Library/BlobVerifierLib.h
new file mode 100644
index 000000000000..667024766681
--- /dev/null
+++ b/OvmfPkg/Include/Library/BlobVerifierLib.h
@@ -0,0 +1,38 @@
+/** @file
+
+  Blob verification library
+
+  This library class allows verifiying whether blobs from external sources
+  (such as QEMU's firmware config) are trusted.
+
+  Copyright (C) 2021, IBM Corporation
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef BLOB_VERIFIER_LIB_H__
+#define BLOB_VERIFIER_LIB_H__
+
+#include <Uefi/UefiBaseType.h>
+#include <Base.h>
+
+/**
+  Verify blob from an external source.
+
+  @param BlobName               The name of the blob
+  @param Buf                    The data of the blob
+  @param BufSize                The size of the blob in bytes
+
+  @retval EFI_SUCCESS           The blob was verified successfully.
+  @retval EFI_ACCESS_DENIED     The blob could not be verified, and therefore
+                                should be considered non-secure.
+**/
+EFI_STATUS
+EFIAPI
+VerifyBlob (
+  IN  CONST CHAR16    *BlobName,
+  IN  CONST VOID      *Buf,
+  UINT32              BufSize
+  );
+
+#endif
diff --git a/OvmfPkg/Library/BlobVerifierLib/NullBlobVerifier.c b/OvmfPkg/Library/BlobVerifierLib/NullBlobVerifier.c
new file mode 100644
index 000000000000..7b31b6ec767d
--- /dev/null
+++ b/OvmfPkg/Library/BlobVerifierLib/NullBlobVerifier.c
@@ -0,0 +1,34 @@
+/** @file
+
+  Null implementation of the blob verifier library.
+
+  Copyright (C) 2021, IBM Corporation
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/BlobVerifierLib.h>
+
+/**
+  Verify blob from an external source.
+
+  @param BlobName               The name of the blob
+  @param Buf                    The data of the blob
+  @param BufSize                The size of the blob in bytes
+
+  @retval EFI_SUCCESS           The blob was verified successfully.
+  @retval EFI_ACCESS_DENIED     The blob could not be verified, and therefore
+                                should be considered non-secure.
+**/
+EFI_STATUS
+EFIAPI
+VerifyBlob (
+  IN  CONST CHAR16    *BlobName,
+  IN  CONST VOID      *Buf,
+  UINT32              BufSize
+  )
+{
+  return EFI_SUCCESS;
+}
-- 
2.25.1



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