141 lines
3.6 KiB
Go
141 lines
3.6 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package autocert
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import (
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"context"
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"crypto"
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"sync"
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"time"
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)
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// renewJitter is the maximum deviation from Manager.RenewBefore.
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const renewJitter = time.Hour
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// domainRenewal tracks the state used by the periodic timers
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// renewing a single domain's cert.
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type domainRenewal struct {
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m *Manager
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domain string
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key crypto.Signer
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timerMu sync.Mutex
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timer *time.Timer
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}
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// start starts a cert renewal timer at the time
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// defined by the certificate expiration time exp.
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//
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// If the timer is already started, calling start is a noop.
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func (dr *domainRenewal) start(exp time.Time) {
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dr.timerMu.Lock()
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defer dr.timerMu.Unlock()
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if dr.timer != nil {
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return
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}
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dr.timer = time.AfterFunc(dr.next(exp), dr.renew)
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}
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// stop stops the cert renewal timer.
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// If the timer is already stopped, calling stop is a noop.
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func (dr *domainRenewal) stop() {
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dr.timerMu.Lock()
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defer dr.timerMu.Unlock()
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if dr.timer == nil {
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return
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}
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dr.timer.Stop()
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dr.timer = nil
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}
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// renew is called periodically by a timer.
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// The first renew call is kicked off by dr.start.
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func (dr *domainRenewal) renew() {
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dr.timerMu.Lock()
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defer dr.timerMu.Unlock()
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if dr.timer == nil {
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return
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}
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ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
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defer cancel()
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// TODO: rotate dr.key at some point?
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next, err := dr.do(ctx)
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if err != nil {
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next = renewJitter / 2
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next += time.Duration(pseudoRand.int63n(int64(next)))
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}
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dr.timer = time.AfterFunc(next, dr.renew)
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testDidRenewLoop(next, err)
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}
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// updateState locks and replaces the relevant Manager.state item with the given
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// state. It additionally updates dr.key with the given state's key.
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func (dr *domainRenewal) updateState(state *certState) {
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dr.m.stateMu.Lock()
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defer dr.m.stateMu.Unlock()
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dr.key = state.key
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dr.m.state[dr.domain] = state
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}
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// do is similar to Manager.createCert but it doesn't lock a Manager.state item.
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// Instead, it requests a new certificate independently and, upon success,
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// replaces dr.m.state item with a new one and updates cache for the given domain.
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//
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// It may lock and update the Manager.state if the expiration date of the currently
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// cached cert is far enough in the future.
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//
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// The returned value is a time interval after which the renewal should occur again.
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func (dr *domainRenewal) do(ctx context.Context) (time.Duration, error) {
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// a race is likely unavoidable in a distributed environment
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// but we try nonetheless
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if tlscert, err := dr.m.cacheGet(ctx, dr.domain); err == nil {
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next := dr.next(tlscert.Leaf.NotAfter)
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if next > dr.m.renewBefore()+renewJitter {
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signer, ok := tlscert.PrivateKey.(crypto.Signer)
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if ok {
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state := &certState{
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key: signer,
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cert: tlscert.Certificate,
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leaf: tlscert.Leaf,
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}
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dr.updateState(state)
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return next, nil
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}
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}
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}
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der, leaf, err := dr.m.authorizedCert(ctx, dr.key, dr.domain)
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if err != nil {
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return 0, err
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}
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state := &certState{
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key: dr.key,
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cert: der,
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leaf: leaf,
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}
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tlscert, err := state.tlscert()
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if err != nil {
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return 0, err
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}
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if err := dr.m.cachePut(ctx, dr.domain, tlscert); err != nil {
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return 0, err
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}
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dr.updateState(state)
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return dr.next(leaf.NotAfter), nil
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}
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func (dr *domainRenewal) next(expiry time.Time) time.Duration {
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d := expiry.Sub(timeNow()) - dr.m.renewBefore()
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// add a bit of randomness to renew deadline
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n := pseudoRand.int63n(int64(renewJitter))
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d -= time.Duration(n)
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if d < 0 {
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return 0
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}
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return d
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}
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var testDidRenewLoop = func(next time.Duration, err error) {}
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