mirror of
https://github.com/edgelesssys/constellation.git
synced 2024-12-18 04:14:33 -05:00
106 lines
2.8 KiB
Go
106 lines
2.8 KiB
Go
/*
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Copyright (c) Edgeless Systems GmbH
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SPDX-License-Identifier: AGPL-3.0-only
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*/
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package vtpm
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import (
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"errors"
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"github.com/google/go-tpm/tpm2"
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"github.com/google/go-tpm/tpmutil"
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)
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const (
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// PCRIndexClusterID is a PCR we extend to mark the node as initialized.
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// The value used to extend is a random generated 32 Byte value.
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PCRIndexClusterID = tpmutil.Handle(15)
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// PCRIndexOwnerID is a PCR we extend to mark the node as initialized.
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// The value used to extend is derived from Constellation's master key.
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// TODO: move to stable, non-debug PCR before use.
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PCRIndexOwnerID = tpmutil.Handle(16)
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)
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// MarkNodeAsBootstrapped marks a node as initialized by extending PCRs.
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func MarkNodeAsBootstrapped(openTPM TPMOpenFunc, clusterID []byte) error {
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tpm, err := openTPM()
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if err != nil {
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return err
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}
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defer tpm.Close()
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// clusterID is used to uniquely identify this running instance of Constellation
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return tpm2.PCREvent(tpm, PCRIndexClusterID, clusterID)
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}
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// IsNodeBootstrapped checks if a node is already bootstrapped by reading PCRs.
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func IsNodeBootstrapped(openTPM TPMOpenFunc) (bool, error) {
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tpm, err := openTPM()
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if err != nil {
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return false, err
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}
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defer tpm.Close()
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idxClusterID := int(PCRIndexClusterID)
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pcrs, err := tpm2.ReadPCRs(tpm, tpm2.PCRSelection{
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Hash: tpm2.AlgSHA256,
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PCRs: []int{idxClusterID},
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})
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if err != nil {
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return false, err
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}
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if len(pcrs[idxClusterID]) == 0 {
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return false, errors.New("cluster ID PCR does not exist")
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}
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return pcrInitialized(pcrs[idxClusterID]), nil
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/* Old code that will be reenabled in the future
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idxOwner := int(PCRIndexOwnerID)
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idxCluster := int(PCRIndexClusterID)
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selection := tpm2.PCRSelection{
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Hash: tpm2.AlgSHA256,
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PCRs: []int{idxOwner, idxCluster},
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}
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pcrs, err := tpm2.ReadPCRs(tpm, selection)
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if err != nil {
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return false, err
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}
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if len(pcrs[idxOwner]) == 0 {
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return false, errors.New("owner ID PCR does not exist")
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}
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if len(pcrs[idxCluster]) == 0 {
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return false, errors.New("cluster ID PCR does not exist")
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}
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ownerInitialized := pcrInitialized(pcrs[idxOwner])
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clusterInitialized := pcrInitialized(pcrs[idxCluster])
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if ownerInitialized == clusterInitialized {
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return ownerInitialized && clusterInitialized, nil
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}
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ownerState := "not initialized"
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if ownerInitialized {
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ownerState = "initialized"
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}
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clusterState := "not initialized"
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if clusterInitialized {
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clusterState = "initialized"
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}
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return false, fmt.Errorf("PCRs %v and %v are not consistent: PCR[%v]=%v (%v), PCR[%v]=%v (%v)", idxOwner, idxCluster, idxOwner, pcrs[idxOwner], ownerState, idxCluster, pcrs[idxCluster], clusterState)
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*/
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}
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// pcrInitialized checks if a PCR value is set to a non-zero value.
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func pcrInitialized(pcr []byte) bool {
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for _, b := range pcr {
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if b != 0 {
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return true
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}
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}
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return false
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}
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