[PATCH] FmpDevicePkg: Enhance capsule verification with secure boot keys

["Liming Sun" <lsun@mellanox.com>]

This commit enhances the FmpDevicePkg package to optionally verify
capsule with the secure boot keys when PcdFmpDevicePkcs7CertBufferXdr
is not set and the new PCD variable PcdFmpDeviceAllowSecureBootKeys
is configured. Below is the check logic:
  - Pass if verified with PK key, or PK key not set yet;
  - Deny if verified with the DBX keys;
  - Verified it against the DB keys;

One purpose for this change is to auto-deploy the UEFI secure boot
keys with UEFI capsule. Initially it's done in trusted environment.
Once secure boot is enabled, the same keys will be used to verify
the signed capsules as well for further updates.

Signed-off-by: Liming Sun <lsun@mellanox.com>
---
 FmpDevicePkg/FmpDevicePkg.dec     |   6 +++
 FmpDevicePkg/FmpDxe/FmpDxe.c      | 109 ++++++++++++++++++++++++++++++++++++--
 FmpDevicePkg/FmpDxe/FmpDxe.h      |   1 +
 FmpDevicePkg/FmpDxe/FmpDxe.inf    |   3 ++
 FmpDevicePkg/FmpDxe/FmpDxeLib.inf |   1 +
 5 files changed, 117 insertions(+), 3 deletions(-)

diff --git a/FmpDevicePkg/FmpDevicePkg.dec b/FmpDevicePkg/FmpDevicePkg.dec
index cab63f5..3aeb89c 100644
--- a/FmpDevicePkg/FmpDevicePkg.dec
+++ b/FmpDevicePkg/FmpDevicePkg.dec
@@ -126,6 +126,12 @@
   # @Prompt Firmware Device Image Type ID
   gFmpDevicePkgTokenSpaceGuid.PcdFmpDeviceImageTypeIdGuid|{0}|VOID*|0x40000010
 
+  ## This option is used to verify the capsule using secure boot keys if the
+  # PcdFmpDevicePkcs7CertBufferXdr is not configured. In such case, the check
+  # will pass if secure boot hasn't been enabled yet.
+  # @A flag to tell whether to use secure boot keys when PcdFmpDevicePkcs7CertBufferXdr is not set.
+  gFmpDevicePkgTokenSpaceGuid.PcdFmpDeviceAllowSecureBootKeys|0x0|UINT8|0x40000012
+
 [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
   ## One or more PKCS7 certificates used to verify a firmware device capsule
   #  update image.  Encoded using the Variable-Length Opaque Data format of RFC
diff --git a/FmpDevicePkg/FmpDxe/FmpDxe.c b/FmpDevicePkg/FmpDxe/FmpDxe.c
index 5884177..6f82aee 100644
--- a/FmpDevicePkg/FmpDxe/FmpDxe.c
+++ b/FmpDevicePkg/FmpDxe/FmpDxe.c
@@ -682,6 +682,102 @@ GetAllHeaderSize (
   return CalculatedSize;
 }
 
+EFI_STATUS
+CheckTheImageWithSecureBootVariable (
+  IN CONST CHAR16    *Name,
+  IN CONST EFI_GUID  *Guid,
+  IN CONST VOID      *Image,
+  IN UINTN           ImageSize
+  )
+{
+  EFI_STATUS          Status;
+  VOID                *Data;
+  UINTN               Length;
+  EFI_SIGNATURE_LIST  *CertList;
+  EFI_SIGNATURE_DATA  *CertData;
+  UINTN               CertCount;
+  UINTN               Index;
+
+  Status = GetVariable2 (Name, Guid, &Data, &Length);
+  if (EFI_ERROR (Status)) {
+    return EFI_NOT_FOUND;
+  }
+
+  CertList = (EFI_SIGNATURE_LIST *) Data;
+  while ((Length > 0) && (Length >= CertList->SignatureListSize)) {
+    if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
+      CertData  = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList +
+        sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
+      CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) -
+        CertList->SignatureHeaderSize) / CertList->SignatureSize;
+
+      for (Index = 0; Index < CertCount; Index++) {
+        Status = AuthenticateFmpImage (
+                   (EFI_FIRMWARE_IMAGE_AUTHENTICATION *)Image,
+                   ImageSize,
+                   CertData->SignatureData,
+                   CertList->SignatureSize - sizeof (EFI_GUID)
+                   );
+        if (!EFI_ERROR (Status))
+          goto Done;
+
+        CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
+      }
+    }
+
+    Length -= CertList->SignatureListSize;
+    CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
+  }
+
+Done:
+  FreePool (Data);
+  return Status;
+}
+
+EFI_STATUS
+CheckTheImageWithSecureBootKeys (
+  IN  CONST VOID  *Image,
+  IN  UINTN       ImageSize
+  )
+{
+  EFI_STATUS  Status;
+
+  // PK check.
+  Status = CheckTheImageWithSecureBootVariable(
+             EFI_PLATFORM_KEY_NAME,
+             &gEfiGlobalVariableGuid,
+             Image,
+             ImageSize
+             );
+  if (!EFI_ERROR (Status) || Status == EFI_NOT_FOUND) {
+    // Return SUCCESS if verified by PK key or PK key not configured.
+    DEBUG ((DEBUG_INFO, "FmpDxe: Verified capsule with PK key.\n"));
+    return EFI_SUCCESS;
+  }
+
+  // DBX check.
+  Status = CheckTheImageWithSecureBootVariable(
+             EFI_IMAGE_SECURITY_DATABASE1,
+             &gEfiImageSecurityDatabaseGuid,
+             Image,
+             ImageSize
+             );
+  if (!EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_INFO, "FmpDxe: Reject capsule with DBX key.\n"));
+    return EFI_SECURITY_VIOLATION;
+  }
+
+  // DB check.
+  DEBUG ((DEBUG_INFO, "FmpDxe: Verify capsule with DB key.\n"));
+  Status = CheckTheImageWithSecureBootVariable(
+             EFI_IMAGE_SECURITY_DATABASE,
+             &gEfiImageSecurityDatabaseGuid,
+             Image,
+             ImageSize
+             );
+  return Status;
+}
+
 /**
   Checks if the firmware image is valid for the device.
 
@@ -728,6 +824,7 @@ CheckTheImage (
   UINT8                             *PublicKeyDataXdrEnd;
   EFI_FIRMWARE_IMAGE_DEP            *Dependencies;
   UINT32                            DependenciesSize;
+  UINT8                             AllowSecureBootKeys;
 
   Status           = EFI_SUCCESS;
   RawSize          = 0;
@@ -782,9 +879,15 @@ CheckTheImage (
   PublicKeyDataXdr    = PcdGetPtr (PcdFmpDevicePkcs7CertBufferXdr);
   PublicKeyDataXdrEnd = PublicKeyDataXdr + PcdGetSize (PcdFmpDevicePkcs7CertBufferXdr);
 
-  if (PublicKeyDataXdr == NULL || (PublicKeyDataXdr == PublicKeyDataXdrEnd)) {
-    DEBUG ((DEBUG_ERROR, "FmpDxe(%s): Invalid certificate, skipping it.\n", mImageIdName));
-    Status = EFI_ABORTED;
+  if (PublicKeyDataXdr == NULL || (PublicKeyDataXdrEnd - PublicKeyDataXdr < sizeof (UINT32))) {
+    AllowSecureBootKeys = PcdGet8 (PcdFmpDeviceAllowSecureBootKeys);
+    if (AllowSecureBootKeys) {
+      DEBUG ((DEBUG_INFO, "FmpDxe: Use secure boot certs.\n"));
+      Status = CheckTheImageWithSecureBootKeys (Image, ImageSize);
+    } else {
+      DEBUG ((DEBUG_ERROR, "FmpDxe(%s): Invalid certificate, skipping it.\n", mImageIdName));
+      Status = EFI_ABORTED;
+    }
   } else {
     //
     // Try each key from PcdFmpDevicePkcs7CertBufferXdr
diff --git a/FmpDevicePkg/FmpDxe/FmpDxe.h b/FmpDevicePkg/FmpDxe/FmpDxe.h
index 30754de..72a6ce6 100644
--- a/FmpDevicePkg/FmpDxe/FmpDxe.h
+++ b/FmpDevicePkg/FmpDxe/FmpDxe.h
@@ -34,6 +34,7 @@
 #include <Protocol/FirmwareManagement.h>
 #include <Protocol/FirmwareManagementProgress.h>
 #include <Protocol/VariableLock.h>
+#include <Guid/ImageAuthentication.h>
 #include <Guid/SystemResourceTable.h>
 #include <Guid/EventGroup.h>
 
diff --git a/FmpDevicePkg/FmpDxe/FmpDxe.inf b/FmpDevicePkg/FmpDxe/FmpDxe.inf
index eeb904a..60b02d4 100644
--- a/FmpDevicePkg/FmpDxe/FmpDxe.inf
+++ b/FmpDevicePkg/FmpDxe/FmpDxe.inf
@@ -58,6 +58,8 @@
 
 [Guids]
   gEfiEndOfDxeEventGroupGuid
+  gEfiCertX509Guid
+  gEfiImageSecurityDatabaseGuid
 
 [Protocols]
   gEdkiiVariableLockProtocolGuid                ## CONSUMES
@@ -74,6 +76,7 @@
   gFmpDevicePkgTokenSpaceGuid.PcdFmpDevicePkcs7CertBufferXdr               ## CONSUMES
   gFmpDevicePkgTokenSpaceGuid.PcdFmpDeviceTestKeySha256Digest              ## CONSUMES
   gFmpDevicePkgTokenSpaceGuid.PcdFmpDeviceImageTypeIdGuid                  ## CONSUMES
+  gFmpDevicePkgTokenSpaceGuid.PcdFmpDeviceAllowSecureBootKeys              ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdTestKeyUsed                            ## SOMETIMES_PRODUCES
 
 [Depex]
diff --git a/FmpDevicePkg/FmpDxe/FmpDxeLib.inf b/FmpDevicePkg/FmpDxe/FmpDxeLib.inf
index 9a93b5e..1308cae 100644
--- a/FmpDevicePkg/FmpDxe/FmpDxeLib.inf
+++ b/FmpDevicePkg/FmpDxe/FmpDxeLib.inf
@@ -74,6 +74,7 @@
   gFmpDevicePkgTokenSpaceGuid.PcdFmpDevicePkcs7CertBufferXdr               ## CONSUMES
   gFmpDevicePkgTokenSpaceGuid.PcdFmpDeviceTestKeySha256Digest              ## CONSUMES
   gFmpDevicePkgTokenSpaceGuid.PcdFmpDeviceImageTypeIdGuid                  ## CONSUMES
+  gFmpDevicePkgTokenSpaceGuid.PcdFmpDeviceAllowSecureBootKeys              ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdTestKeyUsed                            ## SOMETIMES_PRODUCES
 
 [Depex]
-- 
1.8.3.1