forked from smallstep/cli
-
Notifications
You must be signed in to change notification settings - Fork 0
/
create.go
592 lines (484 loc) · 16.2 KB
/
create.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
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
package jwk
import (
"bytes"
"crypto"
"encoding/base64"
"encoding/json"
"fmt"
"github.com/RTradeLtd/ca-cli/command"
"github.com/RTradeLtd/ca-cli/crypto/randutil"
"github.com/RTradeLtd/ca-cli/errs"
"github.com/RTradeLtd/ca-cli/flags"
"github.com/RTradeLtd/ca-cli/jose"
"github.com/RTradeLtd/ca-cli/ui"
"github.com/RTradeLtd/ca-cli/utils"
"github.com/pkg/errors"
"github.com/urfave/cli"
)
const (
// 128-bit salt
pbkdf2SaltSize = 16
// 100k iterations. Nist recommends at least 10k, 1Passsword uses 100k.
pbkdf2Iterations = 100000
)
func createCommand() cli.Command {
return cli.Command{
Name: "create",
Action: command.ActionFunc(createAction),
Usage: "create a JWK (JSON Web Key)",
UsageText: `**step crypto jwk create** <public-jwk-file> <private-jwk-file>
[**--kty**=<type>] [**--alg**=<algorithm>] [**--use**=<use>]
[**--size**=<size>] [**--crv**=<curve>] [**--kid**=<kid>]
[**--from-pem**=<pem-file>] [**--password-file**=<file>]`,
Description: `**step crypto jwk create** generates a new JWK (JSON Web Key) or constructs a
JWK from an existing key. The generated JWK conforms to RFC7517 and can be used
to sign and encrypt data using JWT, JWS, and JWE.
Files containing private keys are encrypted by default. You'll be prompted for
a password. Keys are written with file mode **0600** (i.e., readable and
writable only by the current user).
All flags are optional. Defaults are suitable for most use cases.
## POSITIONAL ARGUMENTS
<public-jwk-file>
: Path to which the the public JWK should be written
<private-jwk-file>
: Path to which the (JWE encrypted) private JWK should be written
## EXIT CODES
This command returns 0 on success and \>0 if any error occurs.
## SECURITY CONSIDERATIONS
All security considerations from **step help crypto** are relevant here.
**Preventing hostile disclosure of non-public key material**
: It is critical that any private and symmetric key material be protected from
unauthorized disclosure or modification. This includes the private key for
asymmetric key types (RSA, EC, and OKP) and the shared secret for symmetric key
types (oct). One means of protection is encryption. Keys can also be stored in
hardware or software "security enclaves" such as HSMs and TPMs or operating
system keychain management tools.
**Key provenance and bindings**
: Key provenance should always be scrutinized. You should not trust a key that
was obtained in an untrustworthy manner (e.g., non-TLS HTTP).
: Usually applications use keys to make authorization decisions based on
attributes "bound" to the key such as the key owner's name or role. In these
scenarios the strength of the system's security depends on the strength of
these "bindings". There are a variety of mechanisms for securely binding
attributes to keys, including:
* Cryptographically binding attributes to the public key using x509
certificates (e.g., as defined in PKIX / RFC2580)
* Cryptographically binding attributes to the public key using JWTs
* Storing the public key or (hashed) shared secret along with the bound
attributes in a secure database
: Cryptographic mechanisms require establishing a "root of trust" that can sign
the bindings (the certificates or JWTs) asserting that the bound attributes are
correct.
## STANDARDS
[RFC7517]
: Jones, M., "JSON Web Key (JWK)", https://tools.ietf.org/html/rfc7517
[RFC7518]
: Jones, M., "JSON Web Algorithms (JWA)", https://tools.ietf.org/html/rfc7518
[RFC7638]
: M. Jones, N. Sakimura., "JSON Web Key (JWK) Thumbprint",
https://tools.ietf.org/html/rfc7638
[RFC8037]
: I. Liusvaara., "CFRG Elliptic Curve Diffie-Hellman (ECDH) and Signatures in
JSON Object Signing and Encryption (JOSE)",
https://tools.ietf.org/html/rfc8037
## EXAMPLES
Create a new JWK using default options:
'''
$ step crypto jwk create jwk.pub.json jwk.json
'''
Create an RSA JWK:
'''
$ step crypto jwk create rsa.pub.json rsa.json --kty RSA
'''
Create a symmetric key (oct key type):
'''
$ step crypto jwk create oct.pub.json oct.json --kty oct
'''
Create a key for use with the Ed25519 cryptosystem:
'''
$ step crypto jwk create ed.pub.json ed.json \
--kty OKP --crv Ed25519
'''
Create a key from an existing PEM file:
'''
$ step crypto jwk create jwk.pub.json jwk.json \
--from-pem key.pem
'''
Create an 4096 bit RSA encryption key:
'''
$ step crypto jwk create rsa-enc.pub.json rsa-enc.json \
--kty RSA --size 4096 --use enc
'''
Create a 192 bit symmetric encryption key for use with AES Key Wrap:
'''
$ step crypto jwk create kw.pub.json kw.json \
--kty oct --size 192 --use enc --alg A192GCMKW
'''
`,
Flags: []cli.Flag{
cli.StringFlag{
Name: "kty, type",
Value: "EC",
Usage: `The <type> of key to create. Corresponds to the **"kty"** JWK parameter.
If unset, default is EC.
: <type> is a case-sensitive string and must be one of:
**EC**
: Create an **elliptic curve** keypair
**oct**
: Create a **symmetric key** (octet stream)
**OKP**
: Create an octet key pair (for **"Ed25519"** curve)
**RSA**
: Create an **RSA** keypair
`,
},
flags.Size,
flags.Curve,
cli.StringFlag{
Name: "alg, algorithm",
Usage: `The <algorithm> intended for use with this key. Corresponds to the
**"alg"** JWK parameter. <algorithm> is case-sensitive. If unset, the default
depends on the key use, key type, and curve (for EC and OKP keys). Defaults are:
: | key type | use | curve | default algorithm |
|----------|-----|---------|-------------------|
| EC | sig | P-256 | ES256 |
| EC | sig | P-384 | ES384 |
| EC | sig | P-521 | ES512 |
| oct | sig | N/A | HS256 |
| RSA | sig | N/A | RS256 |
| OKP | sig | Ed25519 | EdDSA |
| EC | enc | P-256 | ECDH-ES |
| EC | enc | P-384 | ECDH-ES |
| EC | enc | P-521 | ECDH-ES |
| oct | enc | N/A | A256GCMKW |
| RSA | enc | N/A | RSA-OAP-256 |
: If the key **"use"** is **"sig"** (signing) <algorithm> must be one of:
**HS256**
: HMAC using SHA-256
**HS384**
: HMAC using SHA-384
**HS512**
: HMAC using SHA-512
**RS256**
: RSASSA-PKCS1-v1_5 using SHA-256
**RS384**
: RSASSA-PKCS1-v1_5 using SHA-384
**RS512**
: RSASSA-PKCS1-v1_5 using SHA-512
**ES256**
: ECDSA using P-256 and SHA-256
**ES384**
: ECDSA using P-384 and SHA-384
**ES512**
: ECDSA using P-521 and SHA-512
**PS256**
: RSASSA-PSS using SHA-256 and MGF1 with SHA-256
**PS384**
: RSASSA-PSS using SHA-384 and MGF1 with SHA-384
**PS512**
: RSASSA-PSS using SHA-512 and MGF1 with SHA-512
**EdDSA**
: EdDSA signature algorithm
: If the key **"use"** is **"enc"** (encryption) <algorithm> must be one of:
**RSA1_5**
: RSAES-PKCS1-v1_5
**RSA-OAEP**
: RSAES OAEP using default parameters
**RSA-OAEP-256**
: RSAES OAEP using SHA-256 and MGF1 with SHA-256
**A128KW**
: AES Key Wrap with default initial value using 128-bit key
**A192KW**
: AES Key Wrap with default initial value using 192-bit key
**A256KW**
: AES Key Wrap with default initial value using 256-bit key
**dir**
: Direct use of a shared symmetric key as the content encryption key (CEK)
**ECDH-ES**
: Elliptic Curve Diffie-Hellman Ephemeral Static key agreement
**ECDH-ES+A128KW**
: ECDH-ES using Concat KDF and CEK wrapped with "A128KW"
**ECDH-ES+A192KW**
: ECDH-ES using Concat KDF and CEK wrapped with "A192KW"
**ECDH-ES+A256KW**
: ECDH-ES using Concat KDF and CEK wrapped with "A256KW"
**A128GCMKW**
: Key wrapping with AES GCM using 128-bit key
**A192GCMKW**
: Key wrapping with AES GCM using 192-bit key
**A256GCMKW**
: Key wrapping with AES GCM using 256-bit key
**PBES2-HS256+A128KW**
: PBES2 with HMAC SHA-256 and "A128KW" wrapping
**PBES2-HS384+A192KW**
: PBES2 with HMAC SHA-256 and "A192KW" wrapping
**PBES2-HS512+A256KW**
: PBES2 with HMAC SHA-256 and "A256KW" wrapping`,
},
cli.StringFlag{
Name: "use",
Value: "sig",
Usage: `The intended <use> of the public key. Corresponds to the "use" JWK parameter.
The "use" parameter indicates whether the public key is used for encrypting
data or verifying the signature on data.
: <use> is a case-sensitive string and may be one of:
**sig**
: The public key is used for verifying signatures.
**enc**
: The public key is used for encrypting data.
: Other values may be used but the generated JWKs will not work for signing or
encryption with this tool.`,
},
cli.StringFlag{
Name: "kid",
Usage: `The <kid> (key ID) for this JWK. Corresponds to the
"kid" JWK parameter. Used to identify an individual key in a JWK Set, for
example. <kid> is a case-sensitive string. If unset, the JWK Thumbprint
[RFC7638] is used as <kid>. See **step help crypto jwk thumbprint** for more
information on JWK Thumbprints.`,
},
cli.StringFlag{
Name: "key-ops",
Hidden: true, // Not currently implemented
Usage: `The operation(s) for which the key is intended to be used. Corresponds to
the "key_ops" JWK parameter. The '--key-ops' flag can be used multiple times
to indicate multiple intended operations.
<key-op> can be one of the values defined in RFC7517:
sign
Compute digital signature or MAC
verify
Verify digital signature or MAC
encrypt
Encrypt content
decrypt
Decrypt content and validate decryption, if applicable
wrapKey
Encrypt key
unwrapKey
Decrypt key and validate decryption, if applicable
deriveKey
Derive key
deriveBits
Derive bits not to be used as a key
The key operation values are case-sensitive strings. Other values may be
used, but values must not be duplicated.
The '--use' and '--key-ops' flags cannot be used together without also
passing the '--subtle' flag. The '--subtle' flag allows both flags to be used
in a consistent way (e.g., '--key-ops=encrypt --key-ops=decrypt --use=enc').
Multiple unrelated operations (e.g., '--key-ops=encrypt --key-ops=sign') or
inconsistent combinations of '--use' and '--key-ops' (e.g., '--use=enc
--key-ops=sign') are not allowed without also passing the '--insecure' flag
because of potential vulnerabilities associated with using the same key with
multiple algorithms.
Related operations include:
sign + verify
encrypt + decrypt
wrapKey + unwrapKey
If multiple values are passed and at least one is a non-standard value the
'--subtle' flag is required as you must verify that the operations are
related.`,
},
cli.StringFlag{
Name: "from-pem",
Usage: `Create a JWK representing the key encoded in an
existing <pem-file> instead of creating a new key.`,
},
flags.PasswordFile,
flags.NoPassword,
flags.Subtle,
flags.Insecure,
flags.Force,
},
}
}
func createAction(ctx *cli.Context) (err error) {
// require public and private files
if err = errs.NumberOfArguments(ctx, 2); err != nil {
return err
}
// Use password to protect private JWK by default
usePassword := true
passwordFile := ctx.String("password-file")
if ctx.Bool("no-password") {
if len(passwordFile) > 0 {
return errs.IncompatibleFlag(ctx, "no-password", "password-file")
}
if ctx.Bool("insecure") {
usePassword = false
} else {
return errs.RequiredInsecureFlag(ctx, "no-password")
}
}
pubFile := ctx.Args().Get(0)
privFile := ctx.Args().Get(1)
if pubFile == privFile {
return errs.EqualArguments(ctx, "public-jwk-file", "private-jwk-file")
}
// Read password if necessary
var password string
if len(passwordFile) > 0 {
password, err = utils.ReadStringPasswordFromFile(passwordFile)
if err != nil {
return err
}
}
kty := ctx.String("kty")
crv := ctx.String("crv")
alg := ctx.String("alg")
use := ctx.String("use")
kid := ctx.String("kid")
size := ctx.Int("size")
pemFile := ctx.String("from-pem")
switch kty {
case "EC":
if ctx.IsSet("size") {
return errs.IncompatibleFlag(ctx, "size", "--kty EC")
}
case "RSA":
if ctx.IsSet("crv") {
return errs.IncompatibleFlag(ctx, "crv", "--kty RSA")
}
// If size is not set it will use a safe default
if ctx.IsSet("size") {
if size < 2048 && !ctx.Bool("insecure") {
return errs.MinSizeInsecureFlag(ctx, "size", "2048")
}
if size <= 0 {
return errs.MinSizeFlag(ctx, "size", "0")
}
}
case "OKP":
if ctx.IsSet("size") {
return errs.IncompatibleFlag(ctx, "size", "--kty OKP")
}
case "oct":
if ctx.IsSet("crv") {
return errs.IncompatibleFlag(ctx, "crv", "--kty oct")
}
// If size is not set it will use a safe default
if ctx.IsSet("size") {
if size < 16 && !ctx.Bool("insecure") {
return errs.MinSizeInsecureFlag(ctx, "size", "16")
}
if size <= 0 {
return errs.MinSizeFlag(ctx, "size", "0")
}
}
default:
return errs.InvalidFlagValue(ctx, "kty", kty, "EC, RSA, OKP, or oct")
}
// Generate or read secrets
var jwk *jose.JSONWebKey
switch {
case pemFile != "":
jwk, err = jose.GenerateJWKFromPEM(pemFile, ctx.Bool("subtle"))
default:
jwk, err = jose.GenerateJWK(kty, crv, alg, use, kid, size)
}
if err != nil {
return err
}
if ctx.IsSet("kid") {
jwk.KeyID = ctx.String("kid")
} else {
// A hash of a symmetric key can leak information, so we only thumbprint asymmetric keys.
if kty != "oct" {
var hash []byte
hash, err = jwk.Thumbprint(crypto.SHA256)
if err != nil {
return errors.Wrap(err, "error generating JWK thumbprint")
}
jwk.KeyID = base64.RawURLEncoding.EncodeToString(hash)
}
}
jwk.Use = use
if jwk.Algorithm == "" {
jwk.Algorithm = alg
}
if err = jose.ValidateJWK(jwk); err != nil {
return err
}
var jwkPub jose.JSONWebKey
if jose.IsSymmetric(jwk) {
jwkPub = *jwk
} else {
jwkPub = jwk.Public()
}
// Create and write public JWK
b, err := json.MarshalIndent(jwkPub, "", " ")
if err != nil {
return errors.Wrap(err, "error marshaling JWK")
}
if err = utils.WriteFile(pubFile, b, 0600); err != nil {
return errs.FileError(err, pubFile)
}
if jwk.IsPublic() {
ui.Printf("Your public key has been saved in %s.\n", pubFile)
ui.Println("Only the public JWK was generated.")
ui.Println("Cannot retrieve a private key from a public one.")
return nil
}
// Create and write private JWK
if usePassword {
var rcpt jose.Recipient
// Generate JWE encryption key.
if jose.SupportsPBKDF2 {
var key []byte
key, err = ui.PromptPassword("Please enter the password to encrypt the private JWK", ui.WithValue(password))
if err != nil {
return errors.Wrap(err, "error reading password")
}
var salt []byte
salt, err = randutil.Salt(pbkdf2SaltSize)
if err != nil {
return err
}
rcpt = jose.Recipient{
Algorithm: jose.PBES2_HS256_A128KW,
Key: []byte(key),
PBES2Count: pbkdf2Iterations,
PBES2Salt: salt,
}
} else {
var key string
key, err = randutil.Alphanumeric(32)
if err != nil {
return errors.Wrap(err, "error generating password")
}
fmt.Printf("Private JWK file '%s' will be encrypted with the key:\n%s\n", privFile, key)
rcpt = jose.Recipient{Algorithm: jose.A128KW, Key: []byte(key)}
}
b, err = json.Marshal(jwk)
if err != nil {
return errors.Wrap(err, "error marshaling JWK")
}
opts := new(jose.EncrypterOptions)
opts.WithContentType(jose.ContentType("jwk+json"))
var encrypter jose.Encrypter
encrypter, err = jose.NewEncrypter(jose.DefaultEncAlgorithm, rcpt, opts)
if err != nil {
return errors.Wrap(err, "error creating cipher")
}
var obj *jose.JSONWebEncryption
obj, err = encrypter.Encrypt(b)
if err != nil {
return errors.Wrap(err, "error encrypting JWK")
}
var out bytes.Buffer
if err = json.Indent(&out, []byte(obj.FullSerialize()), "", " "); err != nil {
return errors.Wrap(err, "error formatting JSON")
}
b = out.Bytes()
} else {
b, err = json.MarshalIndent(jwk, "", " ")
if err != nil {
return errors.Wrap(err, "error marshaling JWK")
}
}
if err = utils.WriteFile(privFile, b, 0600); err != nil {
return errs.FileError(err, privFile)
}
ui.Printf("Your public key has been saved in %s.\n", pubFile)
ui.Printf("Your private key has been saved in %s.\n", privFile)
return nil
}