-
Notifications
You must be signed in to change notification settings - Fork 417
/
yubikey.go
322 lines (283 loc) · 8.39 KB
/
yubikey.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
//go:build cgo
// +build cgo
package yubikey
import (
"context"
"crypto"
"crypto/x509"
"encoding/hex"
"net/url"
"strings"
"github.com/go-piv/piv-go/piv"
"github.com/pkg/errors"
"github.com/smallstep/certificates/kms/apiv1"
"github.com/smallstep/certificates/kms/uri"
)
// Scheme is the scheme used in uris.
const Scheme = "yubikey"
// YubiKey implements the KMS interface on a YubiKey.
type YubiKey struct {
yk *piv.YubiKey
pin string
managementKey [24]byte
}
// New initializes a new YubiKey.
// TODO(mariano): only one card is currently supported.
func New(ctx context.Context, opts apiv1.Options) (*YubiKey, error) {
managementKey := piv.DefaultManagementKey
if opts.URI != "" {
u, err := uri.ParseWithScheme(Scheme, opts.URI)
if err != nil {
return nil, err
}
if v := u.Pin(); v != "" {
opts.Pin = v
}
if v := u.Get("management-key"); v != "" {
opts.ManagementKey = v
}
}
// Deprecated way to set configuration parameters.
if opts.ManagementKey != "" {
b, err := hex.DecodeString(opts.ManagementKey)
if err != nil {
return nil, errors.Wrap(err, "error decoding managementKey")
}
if len(b) != 24 {
return nil, errors.New("invalid managementKey: length is not 24 bytes")
}
copy(managementKey[:], b[:24])
}
cards, err := piv.Cards()
if err != nil {
return nil, err
}
if len(cards) == 0 {
return nil, errors.New("error detecting yubikey: try removing and reconnecting the device")
}
yk, err := piv.Open(cards[0])
if err != nil {
return nil, errors.Wrap(err, "error opening yubikey")
}
return &YubiKey{
yk: yk,
pin: opts.Pin,
managementKey: managementKey,
}, nil
}
func init() {
apiv1.Register(apiv1.YubiKey, func(ctx context.Context, opts apiv1.Options) (apiv1.KeyManager, error) {
return New(ctx, opts)
})
}
// LoadCertificate implements kms.CertificateManager and loads a certificate
// from the YubiKey.
func (k *YubiKey) LoadCertificate(req *apiv1.LoadCertificateRequest) (*x509.Certificate, error) {
slot, err := getSlot(req.Name)
if err != nil {
return nil, err
}
cert, err := k.yk.Certificate(slot)
if err != nil {
return nil, errors.Wrap(err, "error retrieving certificate")
}
return cert, nil
}
// StoreCertificate implements kms.CertificateManager and stores a certificate
// in the YubiKey.
func (k *YubiKey) StoreCertificate(req *apiv1.StoreCertificateRequest) error {
if req.Certificate == nil {
return errors.New("storeCertificateRequest 'Certificate' cannot be nil")
}
slot, err := getSlot(req.Name)
if err != nil {
return err
}
err = k.yk.SetCertificate(k.managementKey, slot, req.Certificate)
if err != nil {
return errors.Wrap(err, "error storing certificate")
}
return nil
}
// GetPublicKey returns the public key present in the YubiKey signature slot.
func (k *YubiKey) GetPublicKey(req *apiv1.GetPublicKeyRequest) (crypto.PublicKey, error) {
slot, err := getSlot(req.Name)
if err != nil {
return nil, err
}
pub, err := k.getPublicKey(slot)
if err != nil {
return nil, err
}
return pub, nil
}
// CreateKey generates a new key in the YubiKey and returns the public key.
func (k *YubiKey) CreateKey(req *apiv1.CreateKeyRequest) (*apiv1.CreateKeyResponse, error) {
alg, err := getSignatureAlgorithm(req.SignatureAlgorithm, req.Bits)
if err != nil {
return nil, err
}
slot, name, err := getSlotAndName(req.Name)
if err != nil {
return nil, err
}
pub, err := k.yk.GenerateKey(k.managementKey, slot, piv.Key{
Algorithm: alg,
PINPolicy: piv.PINPolicyAlways,
TouchPolicy: piv.TouchPolicyNever,
})
if err != nil {
return nil, errors.Wrap(err, "error generating key")
}
return &apiv1.CreateKeyResponse{
Name: name,
PublicKey: pub,
CreateSignerRequest: apiv1.CreateSignerRequest{
SigningKey: name,
},
}, nil
}
// CreateSigner creates a signer using the key present in the YubiKey signature
// slot.
func (k *YubiKey) CreateSigner(req *apiv1.CreateSignerRequest) (crypto.Signer, error) {
slot, err := getSlot(req.SigningKey)
if err != nil {
return nil, err
}
pub, err := k.getPublicKey(slot)
if err != nil {
return nil, err
}
priv, err := k.yk.PrivateKey(slot, pub, piv.KeyAuth{
PIN: k.pin,
PINPolicy: piv.PINPolicyAlways,
})
if err != nil {
return nil, errors.Wrap(err, "error retrieving private key")
}
signer, ok := priv.(crypto.Signer)
if !ok {
return nil, errors.New("private key is not a crypto.Signer")
}
return signer, nil
}
// Close releases the connection to the YubiKey.
func (k *YubiKey) Close() error {
return errors.Wrap(k.yk.Close(), "error closing yubikey")
}
// getPublicKey returns the public key on a slot. First it attempts to do
// attestation to get a certificate with the public key in it, if this succeeds
// means that the key was generated in the device. If not we'll try to get the
// key from a stored certificate in the same slot.
func (k *YubiKey) getPublicKey(slot piv.Slot) (crypto.PublicKey, error) {
cert, err := k.yk.Attest(slot)
if err != nil {
if cert, err = k.yk.Certificate(slot); err != nil {
return nil, errors.Wrap(err, "error retrieving public key")
}
}
return cert.PublicKey, nil
}
// signatureAlgorithmMapping is a mapping between the step signature algorithm,
// and bits for RSA keys, with yubikey ones.
var signatureAlgorithmMapping = map[apiv1.SignatureAlgorithm]interface{}{
apiv1.UnspecifiedSignAlgorithm: piv.AlgorithmEC256,
apiv1.SHA256WithRSA: map[int]piv.Algorithm{
0: piv.AlgorithmRSA2048,
1024: piv.AlgorithmRSA1024,
2048: piv.AlgorithmRSA2048,
},
apiv1.SHA512WithRSA: map[int]piv.Algorithm{
0: piv.AlgorithmRSA2048,
1024: piv.AlgorithmRSA1024,
2048: piv.AlgorithmRSA2048,
},
apiv1.SHA256WithRSAPSS: map[int]piv.Algorithm{
0: piv.AlgorithmRSA2048,
1024: piv.AlgorithmRSA1024,
2048: piv.AlgorithmRSA2048,
},
apiv1.SHA512WithRSAPSS: map[int]piv.Algorithm{
0: piv.AlgorithmRSA2048,
1024: piv.AlgorithmRSA1024,
2048: piv.AlgorithmRSA2048,
},
apiv1.ECDSAWithSHA256: piv.AlgorithmEC256,
apiv1.ECDSAWithSHA384: piv.AlgorithmEC384,
}
func getSignatureAlgorithm(alg apiv1.SignatureAlgorithm, bits int) (piv.Algorithm, error) {
v, ok := signatureAlgorithmMapping[alg]
if !ok {
return 0, errors.Errorf("YubiKey does not support signature algorithm '%s'", alg)
}
switch v := v.(type) {
case piv.Algorithm:
return v, nil
case map[int]piv.Algorithm:
signatureAlgorithm, ok := v[bits]
if !ok {
return 0, errors.Errorf("YubiKey does not support signature algorithm '%s' with '%d' bits", alg, bits)
}
return signatureAlgorithm, nil
default:
return 0, errors.Errorf("unexpected error: this should not happen")
}
}
var slotMapping = map[string]piv.Slot{
"9a": piv.SlotAuthentication,
"9c": piv.SlotSignature,
"9e": piv.SlotCardAuthentication,
"9d": piv.SlotKeyManagement,
"82": {Key: 0x82, Object: 0x5FC10D},
"83": {Key: 0x83, Object: 0x5FC10E},
"84": {Key: 0x84, Object: 0x5FC10F},
"85": {Key: 0x85, Object: 0x5FC110},
"86": {Key: 0x86, Object: 0x5FC111},
"87": {Key: 0x87, Object: 0x5FC112},
"88": {Key: 0x88, Object: 0x5FC113},
"89": {Key: 0x89, Object: 0x5FC114},
"8a": {Key: 0x8a, Object: 0x5FC115},
"8b": {Key: 0x8b, Object: 0x5FC116},
"8c": {Key: 0x8c, Object: 0x5FC117},
"8d": {Key: 0x8d, Object: 0x5FC118},
"8e": {Key: 0x8e, Object: 0x5FC119},
"8f": {Key: 0x8f, Object: 0x5FC11A},
"90": {Key: 0x90, Object: 0x5FC11B},
"91": {Key: 0x91, Object: 0x5FC11C},
"92": {Key: 0x92, Object: 0x5FC11D},
"93": {Key: 0x93, Object: 0x5FC11E},
"94": {Key: 0x94, Object: 0x5FC11F},
"95": {Key: 0x95, Object: 0x5FC120},
}
func getSlot(name string) (piv.Slot, error) {
slot, _, err := getSlotAndName(name)
return slot, err
}
func getSlotAndName(name string) (piv.Slot, string, error) {
if name == "" {
return piv.SlotSignature, "yubikey:slot-id=9c", nil
}
var slotID string
name = strings.ToLower(name)
if strings.HasPrefix(name, "yubikey:") {
u, err := url.Parse(name)
if err != nil {
return piv.Slot{}, "", errors.Wrapf(err, "error parsing '%s'", name)
}
v, err := url.ParseQuery(u.Opaque)
if err != nil {
return piv.Slot{}, "", errors.Wrapf(err, "error parsing '%s'", name)
}
if slotID = v.Get("slot-id"); slotID == "" {
return piv.Slot{}, "", errors.Wrapf(err, "error parsing '%s': slot-id is missing", name)
}
} else {
slotID = name
}
s, ok := slotMapping[slotID]
if !ok {
return piv.Slot{}, "", errors.Errorf("unsupported slot-id '%s'", name)
}
name = "yubikey:slot-id=" + url.QueryEscape(slotID)
return s, name, nil
}