summaryrefslogtreecommitdiff
path: root/modules/caddytls/tls.go
blob: 81780266b86b24c3060d7c9620c5b9b0957ed7b8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// 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 caddytls

import (
	"crypto/tls"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"runtime/debug"
	"strings"
	"sync"
	"time"

	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/certmagic"
	"go.uber.org/zap"
)

func init() {
	caddy.RegisterModule(TLS{})
	caddy.RegisterModule(AutomateLoader{})
}

// TLS provides TLS facilities including certificate
// loading and management, client auth, and more.
type TLS struct {
	// Caches certificates in memory for quick use during
	// TLS handshakes. Each key is the name of a certificate
	// loader module. All loaded certificates get pooled
	// into the same cache and may be used to complete TLS
	// handshakes for the relevant server names (SNI).
	// Certificates loaded manually (anything other than
	// "automate") are not automatically managed and will
	// have to be refreshed manually before they expire.
	CertificatesRaw caddy.ModuleMap `json:"certificates,omitempty" caddy:"namespace=tls.certificates"`

	// Configures the automation of certificate management.
	Automation *AutomationConfig `json:"automation,omitempty"`

	// Configures session ticket ephemeral keys (STEKs).
	SessionTickets *SessionTicketService `json:"session_tickets,omitempty"`

	// Configures the in-memory certificate cache.
	Cache *CertCacheOptions `json:"cache,omitempty"`

	certificateLoaders []CertificateLoader
	automateNames      []string
	certCache          *certmagic.Cache
	ctx                caddy.Context
	storageCleanTicker *time.Ticker
	storageCleanStop   chan struct{}
	logger             *zap.Logger
}

// CaddyModule returns the Caddy module information.
func (TLS) CaddyModule() caddy.ModuleInfo {
	return caddy.ModuleInfo{
		ID:  "tls",
		New: func() caddy.Module { return new(TLS) },
	}
}

// Provision sets up the configuration for the TLS app.
func (t *TLS) Provision(ctx caddy.Context) error {
	t.ctx = ctx
	t.logger = ctx.Logger(t)

	// set up a new certificate cache; this (re)loads all certificates
	cacheOpts := certmagic.CacheOptions{
		GetConfigForCert: func(cert certmagic.Certificate) (*certmagic.Config, error) {
			return t.getConfigForName(cert.Names[0]), nil
		},
		Logger: t.logger.Named("cache"),
	}
	if t.Automation != nil {
		cacheOpts.OCSPCheckInterval = time.Duration(t.Automation.OCSPCheckInterval)
		cacheOpts.RenewCheckInterval = time.Duration(t.Automation.RenewCheckInterval)
	}
	if t.Cache != nil {
		cacheOpts.Capacity = t.Cache.Capacity
	}
	if cacheOpts.Capacity <= 0 {
		cacheOpts.Capacity = 10000
	}
	t.certCache = certmagic.NewCache(cacheOpts)

	// certificate loaders
	val, err := ctx.LoadModule(t, "CertificatesRaw")
	if err != nil {
		return fmt.Errorf("loading certificate loader modules: %s", err)
	}
	for modName, modIface := range val.(map[string]interface{}) {
		if modName == "automate" {
			// special case; these will be loaded in later using our automation facilities,
			// which we want to avoid doing during provisioning
			if automateNames, ok := modIface.(*AutomateLoader); ok && automateNames != nil {
				t.automateNames = []string(*automateNames)
			} else {
				return fmt.Errorf("loading certificates with 'automate' requires array of strings, got: %T", modIface)
			}
			continue
		}
		t.certificateLoaders = append(t.certificateLoaders, modIface.(CertificateLoader))
	}

	// automation/management policies
	if t.Automation == nil {
		t.Automation = new(AutomationConfig)
	}
	t.Automation.defaultPublicAutomationPolicy = new(AutomationPolicy)
	err = t.Automation.defaultPublicAutomationPolicy.Provision(t)
	if err != nil {
		return fmt.Errorf("provisioning default public automation policy: %v", err)
	}
	for _, n := range t.automateNames {
		// if any names specified by the "automate" loader do not qualify for a public
		// certificate, we should initialize a default internal automation policy
		// (but we don't want to do this unnecessarily, since it may prompt for password!)
		if certmagic.SubjectQualifiesForPublicCert(n) {
			continue
		}
		t.Automation.defaultInternalAutomationPolicy = &AutomationPolicy{
			IssuerRaw: json.RawMessage(`{"module":"internal"}`),
		}
		err = t.Automation.defaultInternalAutomationPolicy.Provision(t)
		if err != nil {
			return fmt.Errorf("provisioning default internal automation policy: %v", err)
		}
		break
	}
	for i, ap := range t.Automation.Policies {
		err := ap.Provision(t)
		if err != nil {
			return fmt.Errorf("provisioning automation policy %d: %v", i, err)
		}
	}

	// session ticket ephemeral keys (STEK) service and provider
	if t.SessionTickets != nil {
		err := t.SessionTickets.provision(ctx)
		if err != nil {
			return fmt.Errorf("provisioning session tickets configuration: %v", err)
		}
	}

	// on-demand rate limiting
	if t.Automation != nil && t.Automation.OnDemand != nil && t.Automation.OnDemand.RateLimit != nil {
		onDemandRateLimiter.SetMaxEvents(t.Automation.OnDemand.RateLimit.Burst)
		onDemandRateLimiter.SetWindow(time.Duration(t.Automation.OnDemand.RateLimit.Interval))
	} else {
		// remove any existing rate limiter
		onDemandRateLimiter.SetMaxEvents(0)
		onDemandRateLimiter.SetWindow(0)
	}

	// load manual/static (unmanaged) certificates - we do this in
	// provision so that other apps (such as http) can know which
	// certificates have been manually loaded, and also so that
	// commands like validate can be a better test
	magic := certmagic.New(t.certCache, certmagic.Config{
		Storage: ctx.Storage(),
		Logger:  t.logger,
	})
	for _, loader := range t.certificateLoaders {
		certs, err := loader.LoadCertificates()
		if err != nil {
			return fmt.Errorf("loading certificates: %v", err)
		}
		for _, cert := range certs {
			err := magic.CacheUnmanagedTLSCertificate(cert.Certificate, cert.Tags)
			if err != nil {
				return fmt.Errorf("caching unmanaged certificate: %v", err)
			}
		}
	}

	// TODO: TEMPORARY UNTIL RELEASE CANDIDATES:
	// MIGRATE MANAGED CERTIFICATE ASSETS TO NEW PATH
	err = t.moveCertificates()
	if err != nil {
		t.logger.Error("migrating certificates", zap.Error(err))
	}
	// END TODO: TEMPORARY.

	return nil
}

// Validate validates t's configuration.
func (t *TLS) Validate() error {
	if t.Automation != nil {
		// ensure that host aren't repeated; since only the first
		// automation policy is used, repeating a host in the lists
		// isn't useful and is probably a mistake; same for two
		// catch-all/default policies
		var hasDefault bool
		hostSet := make(map[string]int)
		for i, ap := range t.Automation.Policies {
			if len(ap.Subjects) == 0 {
				if hasDefault {
					return fmt.Errorf("automation policy %d is the second policy that acts as default/catch-all, but will never be used", i)
				}
				hasDefault = true
			}
			for _, h := range ap.Subjects {
				if first, ok := hostSet[h]; ok {
					return fmt.Errorf("automation policy %d: cannot apply more than one automation policy to host: %s (first match in policy %d)", i, h, first)
				}
				hostSet[h] = i
			}
		}
	}
	if t.Cache != nil {
		if t.Cache.Capacity < 0 {
			return fmt.Errorf("cache capacity must be >= 0")
		}
	}
	return nil
}

// Start activates the TLS module.
func (t *TLS) Start() error {
	// now that we are running, and all manual certificates have
	// been loaded, time to load the automated/managed certificates
	err := t.Manage(t.automateNames)
	if err != nil {
		return fmt.Errorf("automate: managing %v: %v", t.automateNames, err)
	}

	t.keepStorageClean()

	return nil
}

// Stop stops the TLS module and cleans up any allocations.
func (t *TLS) Stop() error {
	// stop the storage cleaner goroutine and ticker
	if t.storageCleanStop != nil {
		close(t.storageCleanStop)
	}
	if t.storageCleanTicker != nil {
		t.storageCleanTicker.Stop()
	}
	return nil
}

// Cleanup frees up resources allocated during Provision.
func (t *TLS) Cleanup() error {
	// stop the certificate cache
	if t.certCache != nil {
		t.certCache.Stop()
	}

	// stop the session ticket rotation goroutine
	if t.SessionTickets != nil {
		t.SessionTickets.stop()
	}

	return nil
}

// Manage immediately begins managing names according to the
// matching automation policy.
func (t *TLS) Manage(names []string) error {
	// for a large number of names, we can be more memory-efficient
	// by making only one certmagic.Config for all the names that
	// use that config, rather than calling ManageAsync once for
	// every name; so first, bin names by AutomationPolicy
	policyToNames := make(map[*AutomationPolicy][]string)
	for _, name := range names {
		ap := t.getAutomationPolicyForName(name)
		policyToNames[ap] = append(policyToNames[ap], name)
	}

	// now that names are grouped by policy, we can simply make one
	// certmagic.Config for each (potentially large) group of names
	// and call ManageAsync just once for the whole batch
	for ap, names := range policyToNames {
		err := ap.magic.ManageAsync(t.ctx.Context, names)
		if err != nil {
			return fmt.Errorf("automate: manage %v: %v", names, err)
		}
	}

	return nil
}

// HandleHTTPChallenge ensures that the HTTP challenge is handled for the
// certificate named by r.Host, if it is an HTTP challenge request. It
// requires that the automation policy for r.Host has an issue of type
// *certmagic.ACMEManager.
func (t *TLS) HandleHTTPChallenge(w http.ResponseWriter, r *http.Request) bool {
	if !certmagic.LooksLikeHTTPChallenge(r) {
		return false
	}
	ap := t.getAutomationPolicyForName(r.Host)
	if ap.magic.Issuer == nil {
		return false
	}
	if am, ok := ap.magic.Issuer.(*ACMEIssuer); ok {
		return certmagic.NewACMEManager(am.magic, am.template).HandleHTTPChallenge(w, r)
	}
	return false
}

// AddAutomationPolicy provisions and adds ap to the list of the app's
// automation policies. If an existing automation policy exists that has
// fewer hosts in its list than ap does, ap will be inserted before that
// other policy (this helps ensure that ap will be prioritized/chosen
// over, say, a catch-all policy).
func (t *TLS) AddAutomationPolicy(ap *AutomationPolicy) error {
	if t.Automation == nil {
		t.Automation = new(AutomationConfig)
	}
	err := ap.Provision(t)
	if err != nil {
		return err
	}
	for i, other := range t.Automation.Policies {
		// if a catch-all policy (or really, any policy with
		// fewer names) exists, prioritize this new policy
		if len(other.Subjects) < len(ap.Subjects) {
			t.Automation.Policies = append(t.Automation.Policies[:i],
				append([]*AutomationPolicy{ap}, t.Automation.Policies[i:]...)...)
			return nil
		}
	}
	// otherwise just append the new one
	t.Automation.Policies = append(t.Automation.Policies, ap)
	return nil
}

func (t *TLS) getConfigForName(name string) *certmagic.Config {
	ap := t.getAutomationPolicyForName(name)
	return ap.magic
}

// getAutomationPolicyForName returns the first matching automation policy
// for the given subject name. If no matching policy can be found, the
// default policy is used, depending on whether the name qualifies for a
// public certificate or not.
func (t *TLS) getAutomationPolicyForName(name string) *AutomationPolicy {
	for _, ap := range t.Automation.Policies {
		if len(ap.Subjects) == 0 {
			return ap // no host filter is an automatic match
		}
		for _, h := range ap.Subjects {
			if certmagic.MatchWildcard(name, h) {
				return ap
			}
		}
	}
	if certmagic.SubjectQualifiesForPublicCert(name) || t.Automation.defaultInternalAutomationPolicy == nil {
		return t.Automation.defaultPublicAutomationPolicy
	}
	return t.Automation.defaultInternalAutomationPolicy
}

// AllMatchingCertificates returns the list of all certificates in
// the cache which could be used to satisfy the given SAN.
func (t *TLS) AllMatchingCertificates(san string) []certmagic.Certificate {
	return t.certCache.AllMatchingCertificates(san)
}

// keepStorageClean starts a goroutine that immediately cleans up all
// known storage units if it was not recently done, and then runs the
// operation at every tick from t.storageCleanTicker.
func (t *TLS) keepStorageClean() {
	t.storageCleanTicker = time.NewTicker(storageCleanInterval)
	t.storageCleanStop = make(chan struct{})
	go func() {
		defer func() {
			if err := recover(); err != nil {
				log.Printf("[PANIC] storage cleaner: %v\n%s", err, debug.Stack())
			}
		}()
		t.cleanStorageUnits()
		for {
			select {
			case <-t.storageCleanStop:
				return
			case <-t.storageCleanTicker.C:
				t.cleanStorageUnits()
			}
		}
	}()
}

func (t *TLS) cleanStorageUnits() {
	storageCleanMu.Lock()
	defer storageCleanMu.Unlock()

	if !storageClean.IsZero() && time.Since(storageClean) < storageCleanInterval {
		return
	}

	options := certmagic.CleanStorageOptions{
		OCSPStaples:            true,
		ExpiredCerts:           true,
		ExpiredCertGracePeriod: 24 * time.Hour * 14,
	}

	// start with the default storage
	certmagic.CleanStorage(t.ctx, t.ctx.Storage(), options)

	// then clean each storage defined in ACME automation policies
	if t.Automation != nil {
		for _, ap := range t.Automation.Policies {
			if ap.storage != nil {
				certmagic.CleanStorage(t.ctx, ap.storage, options)
			}
		}
	}

	storageClean = time.Now()

	t.logger.Info("cleaned up storage units")
}

// CertificateLoader is a type that can load certificates.
// Certificates can optionally be associated with tags.
type CertificateLoader interface {
	LoadCertificates() ([]Certificate, error)
}

// Certificate is a TLS certificate, optionally
// associated with arbitrary tags.
type Certificate struct {
	tls.Certificate
	Tags []string
}

// AutomateLoader is a no-op certificate loader module
// that is treated as a special case: it uses this app's
// automation features to load certificates for the
// list of hostnames, rather than loading certificates
// manually.
type AutomateLoader []string

// CaddyModule returns the Caddy module information.
func (AutomateLoader) CaddyModule() caddy.ModuleInfo {
	return caddy.ModuleInfo{
		ID:  "tls.certificates.automate",
		New: func() caddy.Module { return new(AutomateLoader) },
	}
}

// CertCacheOptions configures the certificate cache.
type CertCacheOptions struct {
	// Maximum number of certificates to allow in the
	// cache. If reached, certificates will be randomly
	// evicted to make room for new ones. Default: 0
	// (no limit).
	Capacity int `json:"capacity,omitempty"`
}

// Variables related to storage cleaning.
var (
	storageCleanInterval = 12 * time.Hour

	storageClean   time.Time
	storageCleanMu sync.Mutex
)

const automateKey = "automate"

// Interface guards
var (
	_ caddy.App          = (*TLS)(nil)
	_ caddy.Provisioner  = (*TLS)(nil)
	_ caddy.Validator    = (*TLS)(nil)
	_ caddy.CleanerUpper = (*TLS)(nil)
)

// TODO: This is temporary until the release candidates
// (beta 16 changed the storage path for certificates),
// after which this function can be deleted
func (t *TLS) moveCertificates() error {
	logger := t.logger.Named("automigrate")

	baseDir := caddy.AppDataDir()

	// if custom storage path was defined, use that instead
	if fs, ok := t.ctx.Storage().(*certmagic.FileStorage); ok && fs.Path != "" {
		baseDir = fs.Path
	}

	oldAcmeDir := filepath.Join(baseDir, "acme")
	oldAcmeCas, err := ioutil.ReadDir(oldAcmeDir)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return fmt.Errorf("listing used ACME CAs: %v", err)
	}

	// get list of used CAs
	oldCANames := make([]string, 0, len(oldAcmeCas))
	for _, fi := range oldAcmeCas {
		if !fi.IsDir() {
			continue
		}
		oldCANames = append(oldCANames, fi.Name())
	}

	for _, oldCA := range oldCANames {
		// make new destination path
		newCAName := oldCA
		if strings.Contains(oldCA, "api.letsencrypt.org") &&
			!strings.HasSuffix(oldCA, "-directory") {
			newCAName += "-directory"
		}
		newBaseDir := filepath.Join(baseDir, "certificates", newCAName)
		err := os.MkdirAll(newBaseDir, 0700)
		if err != nil {
			return fmt.Errorf("making new certs directory: %v", err)
		}

		// list sites in old path
		oldAcmeSitesDir := filepath.Join(oldAcmeDir, oldCA, "sites")
		oldAcmeSites, err := ioutil.ReadDir(oldAcmeSitesDir)
		if err != nil {
			if os.IsNotExist(err) {
				continue
			}
			return fmt.Errorf("listing sites: %v", err)
		}

		if len(oldAcmeSites) > 0 {
			logger.Warn("certificate storage path has changed; attempting one-time auto-migration",
				zap.String("old_folder", oldAcmeSitesDir),
				zap.String("new_folder", newBaseDir),
				zap.String("details", "https://github.com/caddyserver/caddy/issues/2955"))
		}

		// for each site, move its folder and re-encode its metadata
		for _, siteInfo := range oldAcmeSites {
			if !siteInfo.IsDir() {
				continue
			}

			// move the folder
			oldPath := filepath.Join(oldAcmeSitesDir, siteInfo.Name())
			newPath := filepath.Join(newBaseDir, siteInfo.Name())
			logger.Info("moving certificate assets",
				zap.String("ca", oldCA),
				zap.String("site", siteInfo.Name()),
				zap.String("destination", newPath))
			err = os.Rename(oldPath, newPath)
			if err != nil {
				logger.Error("failed moving site to new path; skipping",
					zap.String("old_path", oldPath),
					zap.String("new_path", newPath),
					zap.Error(err))
				continue
			}

			// re-encode metadata file
			metaFilePath := filepath.Join(newPath, siteInfo.Name()+".json")
			metaContents, err := ioutil.ReadFile(metaFilePath)
			if err != nil {
				logger.Error("could not read metadata file",
					zap.String("filename", metaFilePath),
					zap.Error(err))
				continue
			}
			if len(metaContents) == 0 {
				continue
			}
			cr := certmagic.CertificateResource{
				SANs:       []string{siteInfo.Name()},
				IssuerData: json.RawMessage(metaContents),
			}
			newMeta, err := json.MarshalIndent(cr, "", "\t")
			if err != nil {
				logger.Error("encoding new metadata file", zap.Error(err))
				continue
			}
			err = ioutil.WriteFile(metaFilePath, newMeta, 0600)
			if err != nil {
				logger.Error("writing new metadata file", zap.Error(err))
				continue
			}
		}

		// delete now-empty old sites dir (OK if fails)
		os.Remove(oldAcmeSitesDir)
	}

	return nil
}