OvmfPkg/AcpiPlatformDxe: Measure ACPI table from QEMU in TDVF

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

QEMU provides the following three files for guest to install the ACPI
tables:
 - etc/acpi/rsdp
 - etc/acpi/tables
 - etc/table-loader

"etc/acpi/rsdp" and "etc/acpi/tables" are similar, they are only kept
separate because they have different allocation requirements in SeaBIOS.

Both of these fw_cfg files contain preformatted ACPI payload.
"etc/acpi/rsdp" contains only the RSDP table, while "etc/acpi/tables"
contains all other tables, concatenated. To be noted, the tables in these
two files have been filled in by qemu, but two kinds of fields are
incomplete: pointers to other tables and checksums (which depend on the
pointers).

"/etc/table-loader" is a linker/loader which provides the commands to
"patch" the tables in "etc/acpi/tables" and then install them. "Patch"
means to fill the pointers and compute the checksum.

From the security perspective these 3 files are the raw data downloaded
from qemu. They should be measured and extended before they're consumed.

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>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

2 files changed, 33 insertions, 0 deletions

diff --git a/OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf b/OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
index 8939dde425..3fd0483b50 100644
--- a/OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
+++ b/OvmfPkg/AcpiPlatformDxe/AcpiPlatformDxe.inf
@@ -46,6 +46,7 @@
   UefiBootServicesTableLib

   UefiDriverEntryPoint

   HobLib

+  TpmMeasurementLib

 

 [Protocols]

   gEfiAcpiTableProtocolGuid                     # PROTOCOL ALWAYS_CONSUMED

diff --git a/OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c b/OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c
index f0d81d6fd7..68abc34f22 100644
--- a/OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c
+++ b/OvmfPkg/AcpiPlatformDxe/QemuFwCfgAcpi.c
@@ -10,6 +10,7 @@
 

 #include <IndustryStandard/Acpi.h>            // EFI_ACPI_DESCRIPTION_HEADER

 #include <IndustryStandard/QemuLoader.h>      // QEMU_LOADER_FNAME_SIZE

+#include <IndustryStandard/UefiTcgPlatform.h>

 #include <Library/BaseLib.h>                  // AsciiStrCmp()

 #include <Library/BaseMemoryLib.h>            // CopyMem()

 #include <Library/DebugLib.h>                 // DEBUG()

@@ -18,6 +19,7 @@
 #include <Library/QemuFwCfgLib.h>             // QemuFwCfgFindFile()

 #include <Library/QemuFwCfgS3Lib.h>           // QemuFwCfgS3Enabled()

 #include <Library/UefiBootServicesTableLib.h> // gBS

+#include <Library/TpmMeasurementLib.h>

 

 #include "AcpiPlatform.h"

 

@@ -415,6 +417,21 @@ ProcessCmdAllocate (
     (UINT64)Blob->Size,

     (UINT64)(UINTN)Blob->Base

     ));

+

+  //

+  // Measure the data which is downloaded from QEMU.

+  // It has to be done before it is consumed. Because the data will

+  // be updated in the following operations.

+  //

+  TpmMeasureAndLogData (

+    1,

+    EV_PLATFORM_CONFIG_FLAGS,

+    EV_POSTCODE_INFO_ACPI_DATA,

+    ACPI_DATA_LEN,

+    (VOID *)(UINTN)Blob->Base,

+    Blob->Size

+    );

+

   return EFI_SUCCESS;

 

 FreeBlob:

@@ -1126,6 +1143,21 @@ InstallQemuFwCfgTables (
   QemuFwCfgSelectItem (FwCfgItem);

   QemuFwCfgReadBytes (FwCfgSize, LoaderStart);

   RestorePciDecoding (OriginalPciAttributes, OriginalPciAttributesCount);

+

+  //

+  // Measure the "etc/table-loader" which is downloaded from QEMU.

+  // It has to be done before it is consumed. Because it would be

+  // updated in the following operations.

+  //

+  TpmMeasureAndLogData (

+    1,

+    EV_PLATFORM_CONFIG_FLAGS,

+    EV_POSTCODE_INFO_ACPI_DATA,

+    ACPI_DATA_LEN,

+    (VOID *)(UINTN)LoaderStart,

+    FwCfgSize

+    );

+

   LoaderEnd = LoaderStart + FwCfgSize / sizeof *LoaderEntry;

 

   AllocationsRestrictedTo32Bit = NULL;