forked from go-jose/go-jose
-
Notifications
You must be signed in to change notification settings - Fork 0
/
crypter.go
535 lines (455 loc) · 14.6 KB
/
crypter.go
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
/*-
* Copyright 2014 Square Inc.
*
* 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 jose
import (
"crypto/ecdsa"
"crypto/rsa"
"errors"
"fmt"
"reflect"
"gopkg.in/square/go-jose.v2/json"
)
// Encrypter represents an encrypter which produces an encrypted JWE object.
type Encrypter interface {
Encrypt(plaintext []byte) (*JSONWebEncryption, error)
EncryptWithAuthData(plaintext []byte, aad []byte) (*JSONWebEncryption, error)
Options() EncrypterOptions
}
// A generic content cipher
type contentCipher interface {
keySize() int
encrypt(cek []byte, aad, plaintext []byte) (*aeadParts, error)
decrypt(cek []byte, aad []byte, parts *aeadParts) ([]byte, error)
}
// A key generator (for generating/getting a CEK)
type keyGenerator interface {
keySize() int
genKey() ([]byte, rawHeader, error)
}
// A generic key encrypter
type keyEncrypter interface {
encryptKey(cek []byte, alg KeyAlgorithm) (recipientInfo, error) // Encrypt a key
}
// A generic key decrypter
type keyDecrypter interface {
decryptKey(headers rawHeader, recipient *recipientInfo, generator keyGenerator) ([]byte, error) // Decrypt a key
}
// A generic encrypter based on the given key encrypter and content cipher.
type genericEncrypter struct {
contentAlg ContentEncryption
compressionAlg CompressionAlgorithm
cipher contentCipher
recipients []recipientKeyInfo
keyGenerator keyGenerator
extraHeaders map[HeaderKey]interface{}
}
type recipientKeyInfo struct {
keyID string
keyAlg KeyAlgorithm
keyEncrypter keyEncrypter
}
// EncrypterOptions represents options that can be set on new encrypters.
type EncrypterOptions struct {
Compression CompressionAlgorithm
// Optional map of additional keys to be inserted into the protected header
// of a JWS object. Some specifications which make use of JWS like to insert
// additional values here. All values must be JSON-serializable.
ExtraHeaders map[HeaderKey]interface{}
}
// WithHeader adds an arbitrary value to the ExtraHeaders map, initializing it
// if necessary. It returns itself and so can be used in a fluent style.
func (eo *EncrypterOptions) WithHeader(k HeaderKey, v interface{}) *EncrypterOptions {
if eo.ExtraHeaders == nil {
eo.ExtraHeaders = map[HeaderKey]interface{}{}
}
eo.ExtraHeaders[k] = v
return eo
}
// WithContentType adds a content type ("cty") header and returns the updated
// EncrypterOptions.
func (eo *EncrypterOptions) WithContentType(contentType ContentType) *EncrypterOptions {
return eo.WithHeader(HeaderContentType, contentType)
}
// WithType adds a type ("typ") header and returns the updated EncrypterOptions.
func (eo *EncrypterOptions) WithType(typ ContentType) *EncrypterOptions {
return eo.WithHeader(HeaderType, typ)
}
// Recipient represents an algorithm/key to encrypt messages to.
//
// PBES2Count and PBES2Salt correspond with the "p2c" and "p2s" headers used
// on the password-based encryption algorithms PBES2-HS256+A128KW,
// PBES2-HS384+A192KW, and PBES2-HS512+A256KW. If they are not provided a safe
// default of 100000 will be used for the count and a 128-bit random salt will
// be generated.
type Recipient struct {
Algorithm KeyAlgorithm
Key interface{}
KeyID string
PBES2Count int
PBES2Salt []byte
}
// NewEncrypter creates an appropriate encrypter based on the key type
func NewEncrypter(enc ContentEncryption, rcpt Recipient, opts *EncrypterOptions) (Encrypter, error) {
encrypter := &genericEncrypter{
contentAlg: enc,
recipients: []recipientKeyInfo{},
cipher: getContentCipher(enc),
}
if opts != nil {
encrypter.compressionAlg = opts.Compression
encrypter.extraHeaders = opts.ExtraHeaders
}
if encrypter.cipher == nil {
return nil, ErrUnsupportedAlgorithm
}
var keyID string
var rawKey interface{}
switch encryptionKey := rcpt.Key.(type) {
case JSONWebKey:
keyID, rawKey = encryptionKey.KeyID, encryptionKey.Key
case *JSONWebKey:
keyID, rawKey = encryptionKey.KeyID, encryptionKey.Key
default:
rawKey = encryptionKey
}
switch rcpt.Algorithm {
case DIRECT:
// Direct encryption mode must be treated differently
if reflect.TypeOf(rawKey) != reflect.TypeOf([]byte{}) {
return nil, ErrUnsupportedKeyType
}
if encrypter.cipher.keySize() != len(rawKey.([]byte)) {
return nil, ErrInvalidKeySize
}
encrypter.keyGenerator = staticKeyGenerator{
key: rawKey.([]byte),
}
recipientInfo, _ := newSymmetricRecipient(rcpt.Algorithm, rawKey.([]byte))
recipientInfo.keyID = keyID
if rcpt.KeyID != "" {
recipientInfo.keyID = rcpt.KeyID
}
encrypter.recipients = []recipientKeyInfo{recipientInfo}
return encrypter, nil
case ECDH_ES:
// ECDH-ES (w/o key wrapping) is similar to DIRECT mode
typeOf := reflect.TypeOf(rawKey)
if typeOf != reflect.TypeOf(&ecdsa.PublicKey{}) {
return nil, ErrUnsupportedKeyType
}
encrypter.keyGenerator = ecKeyGenerator{
size: encrypter.cipher.keySize(),
algID: string(enc),
publicKey: rawKey.(*ecdsa.PublicKey),
}
recipientInfo, _ := newECDHRecipient(rcpt.Algorithm, rawKey.(*ecdsa.PublicKey))
recipientInfo.keyID = keyID
if rcpt.KeyID != "" {
recipientInfo.keyID = rcpt.KeyID
}
encrypter.recipients = []recipientKeyInfo{recipientInfo}
return encrypter, nil
default:
// Can just add a standard recipient
encrypter.keyGenerator = randomKeyGenerator{
size: encrypter.cipher.keySize(),
}
err := encrypter.addRecipient(rcpt)
return encrypter, err
}
}
// NewMultiEncrypter creates a multi-encrypter based on the given parameters
func NewMultiEncrypter(enc ContentEncryption, rcpts []Recipient, opts *EncrypterOptions) (Encrypter, error) {
cipher := getContentCipher(enc)
if cipher == nil {
return nil, ErrUnsupportedAlgorithm
}
if rcpts == nil || len(rcpts) == 0 {
return nil, fmt.Errorf("square/go-jose: recipients is nil or empty")
}
encrypter := &genericEncrypter{
contentAlg: enc,
recipients: []recipientKeyInfo{},
cipher: cipher,
keyGenerator: randomKeyGenerator{
size: cipher.keySize(),
},
}
if opts != nil {
encrypter.compressionAlg = opts.Compression
}
for _, recipient := range rcpts {
err := encrypter.addRecipient(recipient)
if err != nil {
return nil, err
}
}
return encrypter, nil
}
func (ctx *genericEncrypter) addRecipient(recipient Recipient) (err error) {
var recipientInfo recipientKeyInfo
switch recipient.Algorithm {
case DIRECT, ECDH_ES:
return fmt.Errorf("square/go-jose: key algorithm '%s' not supported in multi-recipient mode", recipient.Algorithm)
}
recipientInfo, err = makeJWERecipient(recipient.Algorithm, recipient.Key)
if recipient.KeyID != "" {
recipientInfo.keyID = recipient.KeyID
}
switch recipient.Algorithm {
case PBES2_HS256_A128KW, PBES2_HS384_A192KW, PBES2_HS512_A256KW:
if sr, ok := recipientInfo.keyEncrypter.(*symmetricKeyCipher); ok {
sr.p2c = recipient.PBES2Count
sr.p2s = recipient.PBES2Salt
}
}
if err == nil {
ctx.recipients = append(ctx.recipients, recipientInfo)
}
return err
}
func makeJWERecipient(alg KeyAlgorithm, encryptionKey interface{}) (recipientKeyInfo, error) {
switch encryptionKey := encryptionKey.(type) {
case *rsa.PublicKey:
return newRSARecipient(alg, encryptionKey)
case *ecdsa.PublicKey:
return newECDHRecipient(alg, encryptionKey)
case []byte:
return newSymmetricRecipient(alg, encryptionKey)
case string:
return newSymmetricRecipient(alg, []byte(encryptionKey))
case *JSONWebKey:
recipient, err := makeJWERecipient(alg, encryptionKey.Key)
recipient.keyID = encryptionKey.KeyID
return recipient, err
default:
return recipientKeyInfo{}, ErrUnsupportedKeyType
}
}
// newDecrypter creates an appropriate decrypter based on the key type
func newDecrypter(decryptionKey interface{}) (keyDecrypter, error) {
switch decryptionKey := decryptionKey.(type) {
case *rsa.PrivateKey:
return &rsaDecrypterSigner{
privateKey: decryptionKey,
}, nil
case *ecdsa.PrivateKey:
return &ecDecrypterSigner{
privateKey: decryptionKey,
}, nil
case []byte:
return &symmetricKeyCipher{
key: decryptionKey,
}, nil
case string:
return &symmetricKeyCipher{
key: []byte(decryptionKey),
}, nil
case JSONWebKey:
return newDecrypter(decryptionKey.Key)
case *JSONWebKey:
return newDecrypter(decryptionKey.Key)
default:
return nil, ErrUnsupportedKeyType
}
}
// Implementation of encrypt method producing a JWE object.
func (ctx *genericEncrypter) Encrypt(plaintext []byte) (*JSONWebEncryption, error) {
return ctx.EncryptWithAuthData(plaintext, nil)
}
// Implementation of encrypt method producing a JWE object.
func (ctx *genericEncrypter) EncryptWithAuthData(plaintext, aad []byte) (*JSONWebEncryption, error) {
obj := &JSONWebEncryption{}
obj.aad = aad
obj.protected = &rawHeader{}
err := obj.protected.set(headerEncryption, ctx.contentAlg)
if err != nil {
return nil, err
}
obj.recipients = make([]recipientInfo, len(ctx.recipients))
if len(ctx.recipients) == 0 {
return nil, fmt.Errorf("square/go-jose: no recipients to encrypt to")
}
cek, headers, err := ctx.keyGenerator.genKey()
if err != nil {
return nil, err
}
obj.protected.merge(&headers)
for i, info := range ctx.recipients {
recipient, err := info.keyEncrypter.encryptKey(cek, info.keyAlg)
if err != nil {
return nil, err
}
err = recipient.header.set(headerAlgorithm, info.keyAlg)
if err != nil {
return nil, err
}
if info.keyID != "" {
err = recipient.header.set(headerKeyID, info.keyID)
if err != nil {
return nil, err
}
}
obj.recipients[i] = recipient
}
if len(ctx.recipients) == 1 {
// Move per-recipient headers into main protected header if there's
// only a single recipient.
obj.protected.merge(obj.recipients[0].header)
obj.recipients[0].header = nil
}
if ctx.compressionAlg != NONE {
plaintext, err = compress(ctx.compressionAlg, plaintext)
if err != nil {
return nil, err
}
err = obj.protected.set(headerCompression, ctx.compressionAlg)
if err != nil {
return nil, err
}
}
for k, v := range ctx.extraHeaders {
b, err := json.Marshal(v)
if err != nil {
return nil, err
}
(*obj.protected)[k] = makeRawMessage(b)
}
authData := obj.computeAuthData()
parts, err := ctx.cipher.encrypt(cek, authData, plaintext)
if err != nil {
return nil, err
}
obj.iv = parts.iv
obj.ciphertext = parts.ciphertext
obj.tag = parts.tag
return obj, nil
}
func (ctx *genericEncrypter) Options() EncrypterOptions {
return EncrypterOptions{
Compression: ctx.compressionAlg,
ExtraHeaders: ctx.extraHeaders,
}
}
// Decrypt and validate the object and return the plaintext. Note that this
// function does not support multi-recipient, if you desire multi-recipient
// decryption use DecryptMulti instead.
func (obj JSONWebEncryption) Decrypt(decryptionKey interface{}) ([]byte, error) {
headers := obj.mergedHeaders(nil)
if len(obj.recipients) > 1 {
return nil, errors.New("square/go-jose: too many recipients in payload; expecting only one")
}
critical, err := headers.getCritical()
if err != nil {
return nil, fmt.Errorf("square/go-jose: invalid crit header")
}
if len(critical) > 0 {
return nil, fmt.Errorf("square/go-jose: unsupported crit header")
}
decrypter, err := newDecrypter(decryptionKey)
if err != nil {
return nil, err
}
cipher := getContentCipher(headers.getEncryption())
if cipher == nil {
return nil, fmt.Errorf("square/go-jose: unsupported enc value '%s'", string(headers.getEncryption()))
}
generator := randomKeyGenerator{
size: cipher.keySize(),
}
parts := &aeadParts{
iv: obj.iv,
ciphertext: obj.ciphertext,
tag: obj.tag,
}
authData := obj.computeAuthData()
var plaintext []byte
recipient := obj.recipients[0]
recipientHeaders := obj.mergedHeaders(&recipient)
cek, err := decrypter.decryptKey(recipientHeaders, &recipient, generator)
if err == nil {
// Found a valid CEK -- let's try to decrypt.
plaintext, err = cipher.decrypt(cek, authData, parts)
}
if plaintext == nil {
return nil, ErrCryptoFailure
}
// The "zip" header parameter may only be present in the protected header.
if comp := obj.protected.getCompression(); comp != "" {
plaintext, err = decompress(comp, plaintext)
}
return plaintext, err
}
// DecryptMulti decrypts and validates the object and returns the plaintexts,
// with support for multiple recipients. It returns the index of the recipient
// for which the decryption was successful, the merged headers for that recipient,
// and the plaintext.
func (obj JSONWebEncryption) DecryptMulti(decryptionKey interface{}) (int, Header, []byte, error) {
globalHeaders := obj.mergedHeaders(nil)
critical, err := globalHeaders.getCritical()
if err != nil {
return -1, Header{}, nil, fmt.Errorf("square/go-jose: invalid crit header")
}
if len(critical) > 0 {
return -1, Header{}, nil, fmt.Errorf("square/go-jose: unsupported crit header")
}
decrypter, err := newDecrypter(decryptionKey)
if err != nil {
return -1, Header{}, nil, err
}
encryption := globalHeaders.getEncryption()
cipher := getContentCipher(encryption)
if cipher == nil {
return -1, Header{}, nil, fmt.Errorf("square/go-jose: unsupported enc value '%s'", string(encryption))
}
generator := randomKeyGenerator{
size: cipher.keySize(),
}
parts := &aeadParts{
iv: obj.iv,
ciphertext: obj.ciphertext,
tag: obj.tag,
}
authData := obj.computeAuthData()
index := -1
var plaintext []byte
var headers rawHeader
for i, recipient := range obj.recipients {
recipientHeaders := obj.mergedHeaders(&recipient)
cek, err := decrypter.decryptKey(recipientHeaders, &recipient, generator)
if err == nil {
// Found a valid CEK -- let's try to decrypt.
plaintext, err = cipher.decrypt(cek, authData, parts)
if err == nil {
index = i
headers = recipientHeaders
break
}
}
}
if plaintext == nil || err != nil {
return -1, Header{}, nil, ErrCryptoFailure
}
// The "zip" header parameter may only be present in the protected header.
if comp := obj.protected.getCompression(); comp != "" {
plaintext, err = decompress(comp, plaintext)
}
sanitized, err := headers.sanitized()
if err != nil {
return -1, Header{}, nil, fmt.Errorf("square/go-jose: failed to sanitize header: %v", err)
}
return index, sanitized, plaintext, err
}