summaryrefslogtreecommitdiff
path: root/modules/caddytls/acmeissuer.go
blob: bbcd5d763072a1f93c1e1157436c2ff913295f9f (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
// 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 (
	"context"
	"crypto/x509"
	"fmt"
	"io/ioutil"
	"net/url"
	"strconv"
	"time"

	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/caddy/v2/caddyconfig"
	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
	"github.com/caddyserver/certmagic"
	"github.com/mholt/acmez"
	"github.com/mholt/acmez/acme"
	"go.uber.org/zap"
)

func init() {
	caddy.RegisterModule(ACMEIssuer{})
}

// ACMEIssuer makes an ACME manager
// for managing certificates using ACME.
//
// TODO: support multiple ACME endpoints (probably
// requires an array of these structs) - caddy would
// also have to load certs from the backup CAs if the
// first one is expired...
type ACMEIssuer struct {
	// The URL to the CA's ACME directory endpoint.
	CA string `json:"ca,omitempty"`

	// The URL to the test CA's ACME directory endpoint.
	// This endpoint is only used during retries if there
	// is a failure using the primary CA.
	TestCA string `json:"test_ca,omitempty"`

	// Your email address, so the CA can contact you if necessary.
	// Not required, but strongly recommended to provide one so
	// you can be reached if there is a problem. Your email is
	// not sent to any Caddy mothership or used for any purpose
	// other than ACME transactions.
	Email string `json:"email,omitempty"`

	// If you have an existing account with the ACME server, put
	// the private key here in PEM format. The ACME client will
	// look up your account information with this key first before
	// trying to create a new one. You can use placeholders here,
	// for example if you have it in an environment variable.
	AccountKey string `json:"account_key,omitempty"`

	// If using an ACME CA that requires an external account
	// binding, specify the CA-provided credentials here.
	ExternalAccount *acme.EAB `json:"external_account,omitempty"`

	// Time to wait before timing out an ACME operation.
	ACMETimeout caddy.Duration `json:"acme_timeout,omitempty"`

	// Configures the various ACME challenge types.
	Challenges *ChallengesConfig `json:"challenges,omitempty"`

	// An array of files of CA certificates to accept when connecting to the
	// ACME CA. Generally, you should only use this if the ACME CA endpoint
	// is internal or for development/testing purposes.
	TrustedRootsPEMFiles []string `json:"trusted_roots_pem_files,omitempty"`

	// Preferences for selecting alternate certificate chains, if offered
	// by the CA. By default, the first offered chain will be selected.
	// If configured, the chains may be sorted and the first matching chain
	// will be selected.
	PreferredChains *ChainPreference `json:"preferred_chains,omitempty"`

	rootPool *x509.CertPool
	template certmagic.ACMEManager
	magic    *certmagic.Config
	logger   *zap.Logger
}

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

// Provision sets up iss.
func (iss *ACMEIssuer) Provision(ctx caddy.Context) error {
	iss.logger = ctx.Logger(iss)

	repl := caddy.NewReplacer()

	// expand email address, if non-empty
	if iss.Email != "" {
		email, err := repl.ReplaceOrErr(iss.Email, true, true)
		if err != nil {
			return fmt.Errorf("expanding email address '%s': %v", iss.Email, err)
		}
		iss.Email = email
	}

	// expand account key, if non-empty
	if iss.AccountKey != "" {
		accountKey, err := repl.ReplaceOrErr(iss.AccountKey, true, true)
		if err != nil {
			return fmt.Errorf("expanding account key PEM '%s': %v", iss.AccountKey, err)
		}
		iss.AccountKey = accountKey
	}

	// DNS providers
	if iss.Challenges != nil && iss.Challenges.DNS != nil && iss.Challenges.DNS.ProviderRaw != nil {
		val, err := ctx.LoadModule(iss.Challenges.DNS, "ProviderRaw")
		if err != nil {
			return fmt.Errorf("loading DNS provider module: %v", err)
		}

		if deprecatedProvider, ok := val.(acmez.Solver); ok {
			// TODO: For a temporary amount of time, we are allowing the use of DNS
			// providers from go-acme/lego since there are so many providers implemented
			// using that API -- they are adapted as an all-in-one Caddy module in this
			// repository: https://github.com/caddy-dns/lego-deprecated - the module is a
			// acmez.Solver type, so we use it directly. The user must set environment
			// variables to configure it. Remove this shim once a sufficient number of
			// DNS providers are implemented for the libdns APIs instead.
			iss.Challenges.DNS.solver = deprecatedProvider
		} else {
			iss.Challenges.DNS.solver = &certmagic.DNS01Solver{
				DNSProvider:        val.(certmagic.ACMEDNSProvider),
				TTL:                time.Duration(iss.Challenges.DNS.TTL),
				PropagationTimeout: time.Duration(iss.Challenges.DNS.PropagationTimeout),
				Resolvers:          iss.Challenges.DNS.Resolvers,
			}
		}
	}

	// add any custom CAs to trust store
	if len(iss.TrustedRootsPEMFiles) > 0 {
		iss.rootPool = x509.NewCertPool()
		for _, pemFile := range iss.TrustedRootsPEMFiles {
			pemData, err := ioutil.ReadFile(pemFile)
			if err != nil {
				return fmt.Errorf("loading trusted root CA's PEM file: %s: %v", pemFile, err)
			}
			if !iss.rootPool.AppendCertsFromPEM(pemData) {
				return fmt.Errorf("unable to add %s to trust pool: %v", pemFile, err)
			}
		}
	}

	var err error
	iss.template, err = iss.makeIssuerTemplate()
	if err != nil {
		return err
	}

	return nil
}

func (iss *ACMEIssuer) makeIssuerTemplate() (certmagic.ACMEManager, error) {
	template := certmagic.ACMEManager{
		CA:                iss.CA,
		TestCA:            iss.TestCA,
		Email:             iss.Email,
		AccountKeyPEM:     iss.AccountKey,
		CertObtainTimeout: time.Duration(iss.ACMETimeout),
		TrustedRoots:      iss.rootPool,
		ExternalAccount:   iss.ExternalAccount,
		Logger:            iss.logger,
	}

	if iss.Challenges != nil {
		if iss.Challenges.HTTP != nil {
			template.DisableHTTPChallenge = iss.Challenges.HTTP.Disabled
			template.AltHTTPPort = iss.Challenges.HTTP.AlternatePort
		}
		if iss.Challenges.TLSALPN != nil {
			template.DisableTLSALPNChallenge = iss.Challenges.TLSALPN.Disabled
			template.AltTLSALPNPort = iss.Challenges.TLSALPN.AlternatePort
		}
		if iss.Challenges.DNS != nil {
			template.DNS01Solver = iss.Challenges.DNS.solver
		}
		template.ListenHost = iss.Challenges.BindHost
	}

	if iss.PreferredChains != nil {
		template.PreferredChains = certmagic.ChainPreference{
			Smallest:       iss.PreferredChains.Smallest,
			AnyCommonName:  iss.PreferredChains.AnyCommonName,
			RootCommonName: iss.PreferredChains.RootCommonName,
		}
	}

	return template, nil
}

// SetConfig sets the associated certmagic config for this issuer.
// This is required because ACME needs values from the config in
// order to solve the challenges during issuance. This implements
// the ConfigSetter interface.
func (iss *ACMEIssuer) SetConfig(cfg *certmagic.Config) {
	iss.magic = cfg
}

// TODO: I kind of hate how each call to these methods needs to
// make a new ACME manager to fill in defaults before using; can
// we find the right place to do that just once and then re-use?

// PreCheck implements the certmagic.PreChecker interface.
func (iss *ACMEIssuer) PreCheck(ctx context.Context, names []string, interactive bool) error {
	return certmagic.NewACMEManager(iss.magic, iss.template).PreCheck(ctx, names, interactive)
}

// Issue obtains a certificate for the given csr.
func (iss *ACMEIssuer) Issue(ctx context.Context, csr *x509.CertificateRequest) (*certmagic.IssuedCertificate, error) {
	return certmagic.NewACMEManager(iss.magic, iss.template).Issue(ctx, csr)
}

// IssuerKey returns the unique issuer key for the configured CA endpoint.
func (iss *ACMEIssuer) IssuerKey() string {
	return certmagic.NewACMEManager(iss.magic, iss.template).IssuerKey()
}

// Revoke revokes the given certificate.
func (iss *ACMEIssuer) Revoke(ctx context.Context, cert certmagic.CertificateResource, reason int) error {
	return certmagic.NewACMEManager(iss.magic, iss.template).Revoke(ctx, cert, reason)
}

// GetACMEIssuer returns iss. This is useful when other types embed ACMEIssuer, because
// type-asserting them to *ACMEIssuer will fail, but type-asserting them to an interface
// with only this method will succeed, and will still allow the embedded ACMEIssuer
// to be accessed and manipulated.
func (iss *ACMEIssuer) GetACMEIssuer() *ACMEIssuer { return iss }

// UnmarshalCaddyfile deserializes Caddyfile tokens into iss.
//
//     ... acme [<directory_url>] {
//         dir <directory_url>
//         test_dir <test_directory_url>
//         email <email>
//         timeout <duration>
//         disable_http_challenge
//         disable_tlsalpn_challenge
//         alt_http_port    <port>
//         alt_tlsalpn_port <port>
//         eab <key_id> <mac_key>
//         trusted_roots <pem_files...>
//         dns <provider_name> [<options>]
//         resolvers <dns_servers...>
//     }
//
func (iss *ACMEIssuer) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
	for d.Next() {
		if d.NextArg() {
			iss.CA = d.Val()
			if d.NextArg() {
				return d.ArgErr()
			}
		}
		for nesting := d.Nesting(); d.NextBlock(nesting); {
			switch d.Val() {
			case "dir":
				if iss.CA != "" {
					return d.Errf("directory is already specified: %s", iss.CA)
				}
				if !d.AllArgs(&iss.CA) {
					return d.ArgErr()
				}

			case "test_dir":
				if !d.AllArgs(&iss.TestCA) {
					return d.ArgErr()
				}

			case "email":
				if !d.AllArgs(&iss.Email) {
					return d.ArgErr()
				}

			case "timeout":
				var timeoutStr string
				if !d.AllArgs(&timeoutStr) {
					return d.ArgErr()
				}
				timeout, err := caddy.ParseDuration(timeoutStr)
				if err != nil {
					return d.Errf("invalid timeout duration %s: %v", timeoutStr, err)
				}
				iss.ACMETimeout = caddy.Duration(timeout)

			case "disable_http_challenge":
				if d.NextArg() {
					return d.ArgErr()
				}
				if iss.Challenges == nil {
					iss.Challenges = new(ChallengesConfig)
				}
				if iss.Challenges.HTTP == nil {
					iss.Challenges.HTTP = new(HTTPChallengeConfig)
				}
				iss.Challenges.HTTP.Disabled = true

			case "disable_tlsalpn_challenge":
				if d.NextArg() {
					return d.ArgErr()
				}
				if iss.Challenges == nil {
					iss.Challenges = new(ChallengesConfig)
				}
				if iss.Challenges.TLSALPN == nil {
					iss.Challenges.TLSALPN = new(TLSALPNChallengeConfig)
				}
				iss.Challenges.TLSALPN.Disabled = true

			case "alt_http_port":
				if !d.NextArg() {
					return d.ArgErr()
				}
				port, err := strconv.Atoi(d.Val())
				if err != nil {
					return d.Errf("invalid port %s: %v", d.Val(), err)
				}
				if iss.Challenges == nil {
					iss.Challenges = new(ChallengesConfig)
				}
				if iss.Challenges.HTTP == nil {
					iss.Challenges.HTTP = new(HTTPChallengeConfig)
				}
				iss.Challenges.HTTP.AlternatePort = port

			case "alt_tlsalpn_port":
				if !d.NextArg() {
					return d.ArgErr()
				}
				port, err := strconv.Atoi(d.Val())
				if err != nil {
					return d.Errf("invalid port %s: %v", d.Val(), err)
				}
				if iss.Challenges == nil {
					iss.Challenges = new(ChallengesConfig)
				}
				if iss.Challenges.TLSALPN == nil {
					iss.Challenges.TLSALPN = new(TLSALPNChallengeConfig)
				}
				iss.Challenges.TLSALPN.AlternatePort = port

			case "eab":
				iss.ExternalAccount = new(acme.EAB)
				if !d.AllArgs(&iss.ExternalAccount.KeyID, &iss.ExternalAccount.MACKey) {
					return d.ArgErr()
				}

			case "trusted_roots":
				iss.TrustedRootsPEMFiles = d.RemainingArgs()

			case "dns":
				if !d.NextArg() {
					return d.ArgErr()
				}
				provName := d.Val()
				if iss.Challenges == nil {
					iss.Challenges = new(ChallengesConfig)
				}
				if iss.Challenges.DNS == nil {
					iss.Challenges.DNS = new(DNSChallengeConfig)
				}
				unm, err := caddyfile.UnmarshalModule(d, "dns.providers."+provName)
				if err != nil {
					return err
				}
				iss.Challenges.DNS.ProviderRaw = caddyconfig.JSONModuleObject(unm, "name", provName, nil)

			case "resolvers":
				if iss.Challenges == nil {
					iss.Challenges = new(ChallengesConfig)
				}
				if iss.Challenges.DNS == nil {
					iss.Challenges.DNS = new(DNSChallengeConfig)
				}
				iss.Challenges.DNS.Resolvers = d.RemainingArgs()
				if len(iss.Challenges.DNS.Resolvers) == 0 {
					return d.ArgErr()
				}

			default:
				return d.Errf("unrecognized ACME issuer property: %s", d.Val())
			}
		}
	}
	return nil
}

// onDemandAskRequest makes a request to the ask URL
// to see if a certificate can be obtained for name.
// The certificate request should be denied if this
// returns an error.
func onDemandAskRequest(ask string, name string) error {
	askURL, err := url.Parse(ask)
	if err != nil {
		return fmt.Errorf("parsing ask URL: %v", err)
	}
	qs := askURL.Query()
	qs.Set("domain", name)
	askURL.RawQuery = qs.Encode()

	resp, err := onDemandAskClient.Get(askURL.String())
	if err != nil {
		return fmt.Errorf("error checking %v to determine if certificate for hostname '%s' should be allowed: %v",
			ask, name, err)
	}
	resp.Body.Close()

	if resp.StatusCode < 200 || resp.StatusCode > 299 {
		return fmt.Errorf("certificate for hostname '%s' not allowed; non-2xx status code %d returned from %v",
			name, resp.StatusCode, ask)
	}

	return nil
}

// ChainPreference describes the client's preferred certificate chain,
// useful if the CA offers alternate chains. The first matching chain
// will be selected.
type ChainPreference struct {
	// Prefer chains with the fewest number of bytes.
	Smallest *bool `json:"smallest,omitempty"`

	// Select first chain having a root with one of
	// these common names.
	RootCommonName []string `json:"root_common_name,omitempty"`

	// Select first chain that has any issuer with one
	// of these common names.
	AnyCommonName []string `json:"any_common_name,omitempty"`
}

// Interface guards
var (
	_ certmagic.PreChecker  = (*ACMEIssuer)(nil)
	_ certmagic.Issuer      = (*ACMEIssuer)(nil)
	_ certmagic.Revoker     = (*ACMEIssuer)(nil)
	_ caddy.Provisioner     = (*ACMEIssuer)(nil)
	_ ConfigSetter          = (*ACMEIssuer)(nil)
	_ caddyfile.Unmarshaler = (*ACMEIssuer)(nil)
)