Another question: how does this deviate from ordinary measured boot? How and when are ACPI tables measured on such systems?
On Mon, 16 Jan 2023 at 03:42, Yao, Jiewen <jiewen....@intel.com> wrote: > > Hi > I have two feedback: > > 1) What we need measure is the input from VMM *before* any modification and > *before* installation. > Please don't use ACPI SDT protocol to get the table *after* modification. > > 2) Why not use TpmMeasureAndLogData() in > https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Include/Library/TpmMeasurementLib.h > ? > Please don't use locate protocol. > > Thank you > Yao, Jiewen > > > -----Original Message----- > > From: Xu, Min M <min.m...@intel.com> > > Sent: Monday, January 16, 2023 9:57 AM > > To: devel@edk2.groups.io > > Cc: Xu, Min M <min.m...@intel.com>; Aktas, Erdem > > <erdemak...@google.com>; James Bottomley <j...@linux.ibm.com>; Yao, > > Jiewen <jiewen....@intel.com>; Gerd Hoffmann <kra...@redhat.com>; > > Tom Lendacky <thomas.lenda...@amd.com>; Michael Roth > > <michael.r...@amd.com> > > Subject: [PATCH V1 1/1] OvmfPkg/AcpiPlatformDxe: Measure ACPI table from > > QEMU in TDVF > > > > From: Min M Xu <min.m...@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 <erdemak...@google.com> > > Cc: James Bottomley <j...@linux.ibm.com> > > Cc: Jiewen Yao <jiewen....@intel.com> > > Cc: Gerd Hoffmann <kra...@redhat.com> > > Cc: Tom Lendacky <thomas.lenda...@amd.com> > > Cc: Michael Roth <michael.r...@amd.com> > > Signed-off-by: Min Xu <min.m...@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 > > > > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. 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