coscel

Documentation

Overview

Package coscel contains the COS TLV event type and related functions.

Index

• Constants
• func FormatEnvVar(name string, value string) (string, error)
• func IsCOSTLV(t cel.TLV) bool
• func ParseEnvVar(envvar string) (string, string, error)
• type COSTLV
  • func ParseToCOSTLV(t cel.TLV) (COSTLV, error)
  • func (c COSTLV) GenerateDigest(hashAlgo crypto.Hash) ([]byte, error)
  • func (c COSTLV) TLV() (cel.TLV, error)
• type ContentType

Constants

const (
	// CELRType indicates the CELR event is a COS content
	// TODO: the value needs to be reserved in the CEL spec
	CELRType uint8 = 80
	// EventPCRIndex is the PCR which should be used for CosEventType events.
	EventPCRIndex = 13
	// EventRTMRIndex is the RTMR to be extended for COS events
	// According to https://uefi.org/specs/UEFI/2.10/38_Confidential_Computing.html
	// CCELMRIndex      TDX Register
	// 0                   MRTD
	// 1                   RTMR[0]
	// 2                   RTMR[1]
	// 3                   RTMR[2]
	// So:
	// 4                   RTMR[3]
	EventRTMRIndex = 3
	// COSCCELMRIndex is the CCMR index to use in eventlog for COS events.
	COSCCELMRIndex = 4
)

Functions

func FormatEnvVar

func FormatEnvVar(name string, value string) (string, error)

FormatEnvVar takes in an environment variable name and its value, run some checks. Concats the name and value by '=' and returns it if valid; returns an error if the name or value is invalid.

func IsCOSTLV

func IsCOSTLV(t cel.TLV) bool

IsCOSTLV check whether t is a COS TLV by its Type value.

func ParseEnvVar

func ParseEnvVar(envvar string) (string, string, error)

ParseEnvVar takes in environment variable as a string (foo=bar), parses it and returns its name and value, or an error if it fails the validation check.

Types

type COSTLV

type COSTLV struct {
	EventType    ContentType
	EventContent []byte
}

COSTLV is a specific event type created for the COS (Google Container-Optimized OS), used as a CEL content.

func ParseToCOSTLV

func ParseToCOSTLV(t cel.TLV) (COSTLV, error)

ParseToCOSTLV constructs a CosTlv from t. It will check for the correct COS event type, and unmarshal the nested event.

func (COSTLV) GenerateDigest

func (c COSTLV) GenerateDigest(hashAlgo crypto.Hash) ([]byte, error)

GenerateDigest generates the digest for the given COS TLV. The whole TLV struct will be marshaled to bytes and feed into the hash algo.

func (COSTLV) TLV

func (c COSTLV) TLV() (cel.TLV, error)

TLV returns the TLV representation of the COS TLV.

type ContentType

type ContentType uint8

ContentType represent a COS content type in a CEL record content.

const (
	ImageRefType ContentType = iota
	ImageDigestType
	RestartPolicyType
	ImageIDType
	ArgType
	EnvVarType
	OverrideArgType
	OverrideEnvType
	LaunchSeparatorType
	MemoryMonitorType
)

Type for COS nested events