[PATCH V1 1/1] OvmfPkg/AcpiPlatformDxe: Measure ACPI table from QEMU in TDVF

["Min Xu" <min.m.xu@intel.com>]

From: Min M Xu <min.m.xu@intel.com>

https://bugzilla.tianocore.org/show_bug.cgi?id=4245

The ACPI tables are downloaded from QEMU. QEMU/VMM is treated as
un-trusted in a td-guest. From the security perspective they should
be measured and extended if possible. So that they can be audited
later. The measurement protocol may be not installed. In this case
it still returns EFI_SUCCESS.

Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
 OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf |   2 +
 OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c     | 168 ++++++++++++++++++++
 2 files changed, 170 insertions(+)

diff --git a/OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf b/OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
index 8939dde42549..ae22bab38cf9 100644
--- a/OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
+++ b/OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
@@ -51,6 +51,8 @@
   gEfiAcpiTableProtocolGuid                     # PROTOCOL ALWAYS_CONSUMED
   gEfiPciIoProtocolGuid                         # PROTOCOL SOMETIMES_CONSUMED
   gQemuAcpiTableNotifyProtocolGuid              # PROTOCOL PRODUCES
+  gEfiCcMeasurementProtocolGuid                 # PROTOCOL SOMETIMES_CONSUMED
+  gEfiAcpiSdtProtocolGuid                       # PROTOCOL SOMETIMES_CONSUMED
 
 [Guids]
   gRootBridgesConnectedEventGroupGuid
diff --git a/OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c b/OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c
index f0d81d6fd73d..f442850c2e00 100644
--- a/OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c
+++ b/OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c
@@ -18,6 +18,8 @@
 #include <Library/QemuFwCfgLib.h>             // QemuFwCfgFindFile()
 #include <Library/QemuFwCfgS3Lib.h>           // QemuFwCfgS3Enabled()
 #include <Library/UefiBootServicesTableLib.h> // gBS
+#include <Protocol/AcpiSystemDescriptionTable.h>
+#include <Protocol/CcMeasurement.h>
 
 #include "AcpiPlatform.h"
 
@@ -812,12 +814,168 @@ UndoCmdWritePointer (
     ));
 }
 
+/**
+  Mesure firmware ACPI table with CcMeasurement Protocol
+
+  @param[in] CcProtocol   Pointer to the CcMeasurment Protocol
+  @param[in] EventData    Pointer to the event data.
+  @param[in] EventSize    Size of event data.
+  @param[in] CfgDataBase  Configuration data base address.
+  @param[in] EventSize    Size of configuration data .
+  @retval  EFI_NOT_FOUND           Cannot locate protocol.
+  @retval  EFI_OUT_OF_RESOURCES    Allocate zero pool failure.
+  @return                          Status codes returned by
+                                   mTcg2Protocol->HashLogExtendEvent.
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+CcMeasureAcpiTable (
+  IN EFI_CC_MEASUREMENT_PROTOCOL  *CcProtocol,
+  IN CHAR8                        *EventData,
+  IN UINT32                       EventSize,
+  IN EFI_PHYSICAL_ADDRESS         CfgDataBase,
+  IN UINTN                        CfgDataLength
+  )
+{
+  EFI_STATUS    Status;
+  EFI_CC_EVENT  *CcEvent;
+  UINT32        MrIndex;
+
+  if (CcProtocol == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  Status = CcProtocol->MapPcrToMrIndex (CcProtocol, 1, &MrIndex);
+  if (EFI_ERROR (Status)) {
+    return EFI_INVALID_PARAMETER;
+  }
+
+  CcEvent = AllocateZeroPool (EventSize + sizeof (EFI_CC_EVENT) - sizeof (CcEvent->Event));
+  if (CcEvent == NULL) {
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  CcEvent->Size                 = EventSize + sizeof (EFI_CC_EVENT) - sizeof (CcEvent->Event);
+  CcEvent->Header.EventType     = EV_PLATFORM_CONFIG_FLAGS;
+  CcEvent->Header.MrIndex       = MrIndex;
+  CcEvent->Header.HeaderSize    = sizeof (EFI_CC_EVENT_HEADER);
+  CcEvent->Header.HeaderVersion = EFI_CC_EVENT_HEADER_VERSION;
+  CopyMem (&CcEvent->Event[0], EventData, EventSize);
+
+  Status = CcProtocol->HashLogExtendEvent (
+                         CcProtocol,
+                         0,
+                         CfgDataBase,
+                         CfgDataLength,
+                         CcEvent
+                         );
+
+  FreePool (CcEvent);
+
+  return Status;
+}
+
 //
 // We'll be saving the keys of installed tables so that we can roll them back
 // in case of failure. 128 tables should be enough for anyone (TM).
 //
 #define INSTALLED_TABLES_MAX  128
 
+/**
+ * The ACPI tables are downloaded from QEMU. From the security perspective these are
+ * external inputs and should be measured and extended if possible. So that they can
+ * be audited later. The measurement protocol may be not installed. In this case it
+ * still returns EFI_SUCCESS.
+ *
+ * @param InstalledKey Pointer to an array which contains the keys of the installed ACPI tables
+ * @param Length       Length of the array
+ * @retval EFI_SUCCESS Successfully measure the ACPI tables
+ * @retval Others      Other errors as indicated
+ */
+STATIC
+EFI_STATUS
+MeasureInstalledTablesFromQemu (
+  IN UINTN  *InstalledKey,
+  IN INT32  Length
+  )
+{
+  EFI_STATUS                   Status;
+  UINTN                        Index1;
+  INT32                        Index2;
+  EFI_ACPI_SDT_HEADER          *Table;
+  EFI_ACPI_TABLE_VERSION       Version;
+  UINTN                        TableKey;
+  EFI_ACPI_SDT_PROTOCOL        *AcpiSdtProtocol;
+  EFI_CC_MEASUREMENT_PROTOCOL  *CcProtocol = NULL;
+
+  Status = gBS->LocateProtocol (&gEfiCcMeasurementProtocolGuid, NULL, (VOID **)&CcProtocol);
+  if (EFI_ERROR (Status)) {
+    //
+    // CcMeasurement protocol is not installed.
+    //
+    return EFI_SUCCESS;
+  }
+
+  Status = gBS->LocateProtocol (&gEfiAcpiSdtProtocolGuid, NULL, (void **)&AcpiSdtProtocol);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "Unable to locate ACPI SDT protocol.\n"));
+    return Status;
+  }
+
+  Index1 = 0;
+  do {
+    Status = AcpiSdtProtocol->GetAcpiTable (Index1, &Table, &Version, &TableKey);
+    if (EFI_ERROR (Status)) {
+      if (Status == EFI_NOT_FOUND) {
+        //
+        // There is no more ACPI tables found. So we return with EFI_SUCCESS.
+        //
+        Status = EFI_SUCCESS;
+      }
+
+      break;
+    }
+
+    for (Index2 = 0; Index2 < Length; Index2++) {
+      if (TableKey == InstalledKey[Index2]) {
+        break;
+      }
+    }
+
+    if (Index2 < Length) {
+      Status = CcMeasureAcpiTable (
+                 CcProtocol,
+                 (CHAR8 *)&Table->Signature,
+                 sizeof (Table->Signature),
+                 (EFI_PHYSICAL_ADDRESS)(UINTN)Table,
+                 Table->Length
+                 );
+      if (EFI_ERROR (Status)) {
+        DEBUG ((
+          DEBUG_ERROR,
+          "Measure ACPI table [%-4.4a] with Size = 0x%x failed! Status = %r\n",
+          (CONST CHAR8 *)&Table->Signature,
+          Table->Length,
+          Status
+          ));
+        break;
+      } else {
+        DEBUG ((
+          DEBUG_INFO,
+          "Measure ACPI table [%-4.4a] with Size = 0x%x\n",
+          (CONST CHAR8 *)&Table->Signature,
+          Table->Length
+          ));
+      }
+    }
+
+    Index1++;
+  } while (TRUE);
+
+  return Status;
+}
+
 /**
   Process a QEMU_LOADER_ADD_POINTER command in order to see if its target byte
   array is an ACPI table, and if so, install it.
@@ -1247,6 +1405,16 @@ InstallQemuFwCfgTables (
     }
   }
 
+  //
+  // Measure the ACPI tables which are downloaded from QEMU
+  //
+  if (Installed > 0) {
+    Status = MeasureInstalledTablesFromQemu (InstalledKey, Installed);
+    if (EFI_ERROR (Status)) {
+      goto UninstallAcpiTables;
+    }
+  }
+
   //
   // Install a protocol to notify that the ACPI table provided by Qemu is
   // ready.
-- 
2.29.2.windows.2