Eric Chiang 9021153e89 internal/eventlog: add code for parsing secure boot variables
This is being prototyped in an internal package as we start to open
source. This code will either live in attest, or in a separate eventlog
package in the future.
2019-09-04 14:25:48 -07:00

186 lines
6.7 KiB
Go

// Copyright 2019 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
// Package eventlog implements experimental logic for parsing the TCG event log format.
package eventlog
import "fmt"
// eventType indicates what kind of data an event is reporting.
type eventType uint32
func isReserved(t eventType) bool {
if 0x00000013 <= t && t <= 0x0000FFFF {
return true
}
if 0x800000E1 <= t && t <= 0x8000FFFF {
return true
}
return false
}
// String returns the name as defined by the TCG specification.
func (e eventType) String() string {
if s, ok := eventTypeNames[e]; ok {
return s
}
s := fmt.Sprintf("eventType(0x%08x)", int(e))
if isReserved(e) {
s += " (reserved)"
}
return s
}
const (
// https://trustedcomputinggroup.org/wp-content/uploads/TCG_PCClient_Specific_Platform_Profile_for_TPM_2p0_1p04_PUBLIC.pdf#page=103
// Reserved for future use.
evPrebootCert eventType = 0x00000000
// Host platform trust chain measurements. The event data can contain one of
// the following, indicating different points of boot: "POST CODE", "SMM CODE",
// "ACPI DATA", "BIS CODE", "Embedded UEFI Driver".
//
// PCR[0] MUST be extended with this event type.
//
// https://trustedcomputinggroup.org/wp-content/uploads/TCG_PCClient_Specific_Platform_Profile_for_TPM_2p0_1p04_PUBLIC.pdf#page=38
evPostCode eventType = 0x00000001
// The event type was never used and is considered reserved.
evUnused eventType = 0x00000002
// Used for PCRs[0,6]. This event type doesn't extend the PCR, the digest MUST
// be all zeros, and the data holds information intended for parsers such as
// delimiting a switch to the agile crypto event format.
//
// This event MUST NOT extend any PCR
evNoAction eventType = 0x00000003
// Delineates the point where the Platform Firmware relinquishes control of TPM
// measurements to the operating system.
//
// Event data size MUST contain either 0x00000000 or 0xFFFFFFFF, the digest MUST
// match the data.
//
// This event MUST extend the PCRs 0 through 7 inclusive.
evSeparator eventType = 0x00000004
// An event indicating a particular action in the boot sequence, for example
// "User Password Entered" or "Booting BCV Device s".
//
// The digests field contains the tagged hash of the event field for each PCR bank.
//
// Used for PCRs [1, 2, 3, 4, 5, and 6].
evAction eventType = 0x00000005
// Used for PCRs defined for OS and application usage. The digest field MUST
// contain a hash of the data. The data contains a TCG_PCClientTaggedEvent
// sructure.
evEventTag eventType = 0x00000006
// Used for PCR[0] only. The digest contains the hash of the SRTM for each PCR
// bank. The data is informative and not expected to match the digest.
evSCRTMContents eventType = 0x00000007
evSCRTMVersion eventType = 0x00000008
// The digests field contains the tagged hash of the microcode patch applied for
// each PCR bank. The data is informative and not expected to match the digest.
evCUPMicrocode eventType = 0x00000009
// TODO(ericchiang): explain these events
evPlatformConfigFiles eventType = 0x0000000A
evTableOfDevices eventType = 0x0000000B
// Can be used for any PCRs except 0, 1, 2, or 3.
evCompactHash eventType = 0x0000000C
// IPL events are deprecated
evIPL eventType = 0x0000000D
evIPLPartitionData eventType = 0x0000000E
// Used for PCR[0] only.
//
// TODO(ericchiang): explain these events
evNonhostCode eventType = 0x0000000F
evNonhostConfig eventType = 0x00000010
evNonhostInfo eventType = 0x00000011
evOmitBootDeviceEvents eventType = 0x00000012
// The following events are UEFI specific.
// Data contains a UEFI_VARIABLE_DATA structure.
evEFIVariableDriverConfig eventType = 0x80000001 // PCR[1,3,5]
evEFIVariableBoot eventType = 0x80000002 // PCR[1]
// Data contains a UEFI_IMAGE_LOAD_EVENT structure.
evEFIBootServicesApplication eventType = 0x80000003 // PCR[2,4]
evEFIBootServicesDriver eventType = 0x80000004 // PCR[0,2]
evEFIRuntimeServicesDriver eventType = 0x80000005 // PCR[2,4]
// Data contains a UEFI_GPT_DATA structure.
evEFIGPTEvent eventType = 0x80000006 // PCR[5]
evEFIAction eventType = 0x80000007 // PCR[1,2,3,4,5,6,7]
// Data contains a UEFI_PLATFORM_FIRMWARE_BLOB structure.
evEFIPlatformFirmwareBlob eventType = 0x80000008 // PCR[0,2,4]
// Data contains a UEFI_HANDOFF_TABLE_POINTERS structure.
evEFIHandoffTables eventType = 0x80000009 // PCR[1]
// The digests field contains the tagged hash of the H-CRTM event
// data for each PCR bank.
//
// The Event Data MUST be the string: “HCRTM”.
evEFIHCRTMEvent eventType = 0x80000010 // PCR[0]
// Data contains a UEFI_VARIABLE_DATA structure.
evEFIVariableAuthority eventType = 0x800000E0 // PCR[7]
)
var eventTypeNames = map[eventType]string{
evPrebootCert: "EV_PREBOOT_CERT",
evPostCode: "EV_POST_CODE",
evUnused: "EV_UNUSED",
evNoAction: "EV_NO_ACTION",
evSeparator: "EV_SEPARATOR",
evAction: "EV_ACTION",
evEventTag: "EV_EVENT_TAG",
evSCRTMContents: "EV_S_CRTM_CONTENTS",
evSCRTMVersion: "EV_S_CRTM_VERSION",
evCUPMicrocode: "EV_CPU_MICROCODE",
evPlatformConfigFiles: "EV_PLATFORM_CONFIG_FLAGS",
evTableOfDevices: "EV_TABLE_OF_DEVICES",
evCompactHash: "EV_COMPACT_HASH",
evIPL: "EV_IPL (deprecated)",
evIPLPartitionData: "EV_IPL_PARTITION_DATA (deprecated)",
evNonhostCode: "EV_NONHOST_CODE",
evNonhostConfig: "EV_NONHOST_CONFIG",
evNonhostInfo: "EV_NONHOST_INFO",
evOmitBootDeviceEvents: "EV_OMIT_BOOT_DEVICE_EVENTS",
// UEFI events
evEFIVariableDriverConfig: "EV_EFI_VARIABLE_DRIVER_CONFIG",
evEFIVariableBoot: "EV_EFI_VARIABLE_BOOT",
evEFIBootServicesApplication: "EV_EFI_BOOT_SERVICES_APPLICATION",
evEFIBootServicesDriver: "EV_EFI_BOOT_SERVICES_DRIVER",
evEFIRuntimeServicesDriver: "EV_EFI_RUNTIME_SERVICES_DRIVER",
evEFIGPTEvent: "EV_EFI_GPT_EVENT",
evEFIAction: "EV_EFI_ACTION",
evEFIPlatformFirmwareBlob: "EV_EFI_PLATFORM_FIRMWARE_BLOB",
evEFIHandoffTables: "EV_EFI_HANDOFF_TABLES",
evEFIHCRTMEvent: "EV_EFI_HCRTM_EVENT",
evEFIVariableAuthority: "EV_EFI_VARIABLE_AUTHORITY",
}