-
Notifications
You must be signed in to change notification settings - Fork 40
/
client_credentials.go
382 lines (317 loc) · 10.9 KB
/
client_credentials.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
// Copyright (c) HashiCorp Inc. All rights reserved.
// Licensed under the MPL-2.0 License. See NOTICE.txt in the project root for license information.
package auth
import (
"bytes"
"context"
"crypto"
"crypto/ecdsa"
"crypto/rand"
"crypto/rsa"
"crypto/sha1"
"crypto/x509"
"encoding/base64"
"encoding/json"
"fmt"
"io"
"net/http"
"net/url"
"strconv"
"strings"
"time"
"github.com/hashicorp/go-azure-sdk/sdk/environments"
"github.com/hashicorp/go-uuid"
"golang.org/x/oauth2"
)
type clientCredentialsType string
const (
clientCredentialsAssertionType clientCredentialsType = "ClientCredentials"
clientCredentialsSecretType clientCredentialsType = "ClientSecret"
)
// clientCredentialsConfig is the configuration for using client credentials flow.
//
// For more information see:
// https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow#get-a-token
// https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-certificate-credentials
type clientCredentialsConfig struct {
// Environment is the national cloud environment to use
Environment environments.Environment
// TenantID is the required tenant ID for the primary token
TenantID string
// AuxiliaryTenantIDs is an optional list of tenant IDs for which to obtain additional tokens
AuxiliaryTenantIDs []string
// ClientID is the application's ID.
ClientID string
// ClientSecret is the application's secret.
ClientSecret string
// PrivateKey contains the contents of an RSA private key or the
// contents of a PEM file that contains a private key. The provided
// private key is used to sign JWT assertions.
// PEM containers with a passphrase are not supported.
// Use the following command to convert a PKCS 12 file into a PEM.
//
// $ openssl pkcs12 -in key.p12 -out key.pem -nodes
//
PrivateKey crypto.PrivateKey
// Certificate contains the (optionally PEM encoded) X509 certificate registered
// for the application with which you are authenticating. Used when FederatedAssertion is empty.
Certificate *x509.Certificate
// FederatedAssertion contains a JWT provided by a trusted third-party vendor
// for obtaining an access token with a federated credential. When empty, an
// assertion will be created and signed using the specified PrivateKey and Certificate
FederatedAssertion string
// Scopes specifies a list of requested permission scopes (used for v2 tokens)
Scopes []string
// TokenURL is the clientCredentialsToken endpoint, which overrides the default endpoint constructed from a tenant ID
TokenURL string
// Audience optionally specifies the intended audience of the
// request. If empty, the value of TokenURL is used as the
// intended audience.
Audience string
}
// TokenSource provides a source for obtaining access tokens using ClientAssertionAuthorizer or ClientSecretAuthorizer.
func (c *clientCredentialsConfig) TokenSource(_ context.Context, authType clientCredentialsType) (Authorizer, error) {
switch authType {
case clientCredentialsAssertionType:
return NewCachedAuthorizer(&ClientAssertionAuthorizer{
conf: c,
})
case clientCredentialsSecretType:
return NewCachedAuthorizer(&ClientSecretAuthorizer{
conf: c,
})
}
return nil, fmt.Errorf("internal-error: unimplemented authType %q", string(authType))
}
type clientAssertionTokenHeader struct {
Algorithm string `json:"alg"`
Type string `json:"typ"`
KeyId string `json:"kid"`
}
func (h *clientAssertionTokenHeader) encode() (string, error) {
b, err := json.Marshal(h)
if err != nil {
return "", err
}
return base64.RawURLEncoding.EncodeToString(b), nil
}
type clientAssertionTokenClaims struct {
Audience string `json:"aud"`
Expiry int64 `json:"exp"`
Issuer string `json:"iss"`
JwtId string `json:"jti"`
NotBefore int64 `json:"nbf"`
Subject string `json:"sub"`
}
func (c *clientAssertionTokenClaims) encode() (string, error) {
b, err := json.Marshal(c)
if err != nil {
return "", err
}
return base64.RawURLEncoding.EncodeToString(b), nil
}
type clientAssertionToken struct {
header clientAssertionTokenHeader
claims clientAssertionTokenClaims
}
func (c *clientAssertionToken) encode(key crypto.PrivateKey) (*string, error) {
var err error
c.claims.NotBefore = time.Now().Unix()
c.claims.Expiry = time.Now().Add(time.Hour).Unix()
c.claims.JwtId, err = uuid.GenerateUUID()
if err != nil {
return nil, err
}
var hash = crypto.SHA256
var sign func([]byte, []byte) ([]byte, error)
// determine algorithm and signing function, fail for unsupported keys
if k, ok := key.(*ecdsa.PrivateKey); ok {
c.header.Algorithm = "ES256"
sign = func(data []byte, sum []byte) ([]byte, error) {
return ecdsa.SignASN1(rand.Reader, k, sum)
}
} else if k, ok := key.(*rsa.PrivateKey); ok {
c.header.Algorithm = "RS256"
sign = func(data []byte, sum []byte) ([]byte, error) {
return rsa.SignPKCS1v15(rand.Reader, k, hash, sum)
}
} else {
return nil, fmt.Errorf("unrecognized/unsupported key type: %T", key)
}
// encode the header
hs, err := c.header.encode()
if err != nil {
return nil, err
}
// encode the claims
cs, err := c.claims.encode()
if err != nil {
return nil, err
}
// sign the token
ss := fmt.Sprintf("%s.%s", hs, cs)
h := hash.New()
h.Write([]byte(ss))
sig, err := sign([]byte(ss), h.Sum(nil))
if err != nil {
return nil, err
}
ret := fmt.Sprintf("%s.%s", ss, base64.RawURLEncoding.EncodeToString(sig))
return &ret, nil
}
var _ Authorizer = &ClientAssertionAuthorizer{}
type ClientAssertionAuthorizer struct {
conf *clientCredentialsConfig
}
func (a *ClientAssertionAuthorizer) assertion(tokenUrl string) (*string, error) {
if a.conf == nil {
return nil, fmt.Errorf("internal-error: ClientAssertionAuthorizer not configured")
}
if a.conf.Certificate == nil {
return nil, fmt.Errorf("internal-error: ClientAssertionAuthorizer misconfigured; Certificate was nil")
}
keySig := sha1.Sum(a.conf.Certificate.Raw)
keyId := base64.URLEncoding.EncodeToString(keySig[:])
audience := a.conf.Audience
if audience == "" {
audience = tokenUrl
}
t := clientAssertionToken{
header: clientAssertionTokenHeader{
Type: "JWT",
KeyId: keyId,
},
claims: clientAssertionTokenClaims{
Audience: audience,
Issuer: a.conf.ClientID,
Subject: a.conf.ClientID,
},
}
assertion, err := t.encode(a.conf.PrivateKey)
if err != nil {
return nil, fmt.Errorf("ClientAssertionAuthorizer: failed to encode and sign JWT assertion: %v", err)
}
return assertion, nil
}
func (a *ClientAssertionAuthorizer) token(ctx context.Context, tokenUrl string) (*oauth2.Token, error) {
if a.conf == nil {
return nil, fmt.Errorf("internal-error: ClientAssertionAuthorizer not configured")
}
assertion := a.conf.FederatedAssertion
if assertion == "" {
a, err := a.assertion(tokenUrl)
if err != nil {
return nil, err
}
if a == nil {
return nil, fmt.Errorf("ClientAssertionAuthorizer: assertion was nil")
}
assertion = *a
}
v := url.Values{
"client_assertion": {assertion},
"client_assertion_type": {"urn:ietf:params:oauth:client-assertion-type:jwt-bearer"},
"client_id": {a.conf.ClientID},
"grant_type": {"client_credentials"},
// NOTE: we intentionally only support v2 (MSAL) Tokens at this time since v1 (ADAL) is EOL
"scope": []string{
strings.Join(a.conf.Scopes, " "),
},
}
return clientCredentialsToken(ctx, tokenUrl, &v)
}
func (a *ClientAssertionAuthorizer) Token(ctx context.Context, _ *http.Request) (*oauth2.Token, error) {
if a.conf == nil {
return nil, fmt.Errorf("could not request token: conf is nil")
}
tokenUrl := a.conf.TokenURL
if tokenUrl == "" {
if a.conf.Environment.Authorization == nil {
return nil, fmt.Errorf("no `authorization` configuration was found for this environment")
}
tokenUrl = tokenEndpoint(*a.conf.Environment.Authorization, a.conf.TenantID)
}
return a.token(ctx, tokenUrl)
}
// AuxiliaryTokens returns additional tokens for auxiliary tenant IDs, for use in multi-tenant scenarios
func (a *ClientAssertionAuthorizer) AuxiliaryTokens(ctx context.Context, _ *http.Request) ([]*oauth2.Token, error) {
if a.conf == nil {
return nil, fmt.Errorf("could not request token: conf is nil")
}
tokens := make([]*oauth2.Token, 0)
if len(a.conf.AuxiliaryTenantIDs) == 0 {
return tokens, nil
}
for _, tenantId := range a.conf.AuxiliaryTenantIDs {
tokenUrl := a.conf.TokenURL
if tokenUrl == "" {
if a.conf.Environment.Authorization == nil {
return nil, fmt.Errorf("no `authorization` configuration was found for this environment")
}
tokenUrl = tokenEndpoint(*a.conf.Environment.Authorization, tenantId)
}
token, err := a.token(ctx, tokenUrl)
if err != nil {
return tokens, err
}
tokens = append(tokens, token)
}
return tokens, nil
}
func clientCredentialsToken(ctx context.Context, endpoint string, params *url.Values) (*oauth2.Token, error) {
req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewBuffer([]byte(params.Encode())))
if err != nil {
return nil, fmt.Errorf("clientCredentialsToken: failed to build request: %+v", err)
}
req.Header.Set("Accept", "application/json")
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
resp, err := Client.Do(req)
if err != nil {
return nil, fmt.Errorf("clientCredentialsToken: cannot request token: %v", err)
}
defer resp.Body.Close()
body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
if err != nil {
return nil, fmt.Errorf("clientCredentialsToken: cannot parse response: %v", err)
}
if c := resp.StatusCode; c < 200 || c > 299 {
return nil, fmt.Errorf("clientCredentialsToken: received HTTP status %d with response: %s", resp.StatusCode, body)
}
// clientCredentialsToken response can arrive with numeric values as integers or strings :(
var tokenRes struct {
AccessToken string `json:"access_token"`
TokenType string `json:"token_type"`
IDToken string `json:"id_token"`
Resource string `json:"resource"`
Scope string `json:"scope"`
ExpiresIn interface{} `json:"expires_in"` // relative seconds from now
ExpiresOn interface{} `json:"expires_on"` // timestamp
}
if err := json.Unmarshal(body, &tokenRes); err != nil {
return nil, fmt.Errorf("clientCredentialsToken: cannot unmarshal response: %v", err)
}
token := &oauth2.Token{
AccessToken: tokenRes.AccessToken,
TokenType: tokenRes.TokenType,
}
var secs time.Duration
if exp, ok := tokenRes.ExpiresIn.(string); ok && exp != "" {
if v, err := strconv.Atoi(exp); err == nil {
secs = time.Duration(v)
}
} else if exp, ok := tokenRes.ExpiresIn.(int64); ok {
secs = time.Duration(exp)
} else if exp, ok := tokenRes.ExpiresIn.(float64); ok {
secs = time.Duration(exp)
}
if secs > 0 {
token.Expiry = time.Now().Add(secs * time.Second)
}
return token, nil
}
func tokenEndpoint(endpoint environments.Authorization, tenant string) string {
if tenant == "" {
tenant = "common"
}
return fmt.Sprintf("%s/%s/oauth2/v2.0/token", endpoint.LoginEndpoint, tenant)
}