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https://github.com/edgelesssys/constellation.git
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59 lines
1.6 KiB
Go
59 lines
1.6 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 nodelock handles locking operations on the node.
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package nodelock
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import (
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"io"
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"sync/atomic"
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"github.com/edgelesssys/constellation/v2/internal/attestation/initialize"
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"github.com/edgelesssys/constellation/v2/internal/attestation/vtpm"
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)
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// Lock locks the node once there the join or the init is at a point
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// where there is no turning back and the other operation does not need
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// to continue.
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//
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// This can be viewed as a state machine with two states: unlocked and locked.
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// There is no way to unlock, so the state changes only once from unlock to
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// locked.
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type Lock struct {
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tpm vtpm.TPMOpenFunc
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marker markAsBootstrapped
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inner atomic.Bool
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}
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// New creates a new NodeLock, which is unlocked.
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func New(tpm vtpm.TPMOpenFunc) *Lock {
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return &Lock{
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tpm: tpm,
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marker: initialize.MarkNodeAsBootstrapped,
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}
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}
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// TryLockOnce tries to lock the node. If the node is already locked, it
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// returns false. If the node is unlocked, it locks it and returns true.
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func (l *Lock) TryLockOnce(clusterID []byte) (bool, error) {
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// CompareAndSwap first checks if the node is currently unlocked.
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// If it was already locked, it returns early.
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// If it is unlocked, it swaps the value to locked atomically and continues.
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if !l.inner.CompareAndSwap(unlocked, locked) {
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return false, nil
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}
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return true, l.marker(l.tpm, clusterID)
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}
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// markAsBootstrapped is a function that marks the node as bootstrapped in the TPM.
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type markAsBootstrapped func(openDevice func() (io.ReadWriteCloser, error), clusterID []byte) error
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const (
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unlocked = false
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locked = true
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)
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