{{ message }}
Repository navigation
Expand file tree
/
Copy pathhandshake_server.go
More file actions
1006 lines (892 loc) · 29.7 KB
/
Copy pathhandshake_server.go
File metadata and controls
1006 lines (892 loc) · 29.7 KB
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
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE-Go file.
package reality
import (
"context"
"crypto"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rsa"
"crypto/subtle"
"crypto/x509"
"encoding/binary"
"errors"
"fmt"
"hash"
"io"
"time"
"github.com/xtls/reality/fips140tls"
)
// serverHandshakeState contains details of a server handshake in progress.
// It's discarded once the handshake has completed.
type serverHandshakeState struct {
c *Conn
ctx context.Context
clientHello *clientHelloMsg
hello *serverHelloMsg
suite *cipherSuite
ecdheOk bool
ecSignOk bool
rsaDecryptOk bool
rsaSignOk bool
sessionState *SessionState
finishedHash finishedHash
masterSecret []byte
cert *Certificate
}
// serverHandshake performs a TLS handshake as a server.
func (c *Conn) serverHandshake(ctx context.Context) error {
clientHello, ech, err := c.readClientHello(ctx)
if err != nil {
return err
}
if c.vers == VersionTLS13 {
hs := serverHandshakeStateTLS13{
c: c,
ctx: ctx,
clientHello: clientHello,
echContext: ech,
}
return hs.handshake()
}
hs := serverHandshakeState{
c: c,
ctx: ctx,
clientHello: clientHello,
}
return hs.handshake()
}
func (hs *serverHandshakeState) handshake() error {
c := hs.c
if err := hs.processClientHello(); err != nil {
return err
}
// For an overview of TLS handshaking, see RFC 5246, Section 7.3.
c.buffering = true
if err := hs.checkForResumption(); err != nil {
return err
}
if hs.sessionState != nil {
// The client has included a session ticket and so we do an abbreviated handshake.
if err := hs.doResumeHandshake(); err != nil {
return err
}
if err := hs.establishKeys(); err != nil {
return err
}
if err := hs.sendSessionTicket(); err != nil {
return err
}
if err := hs.sendFinished(c.serverFinished[:]); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
c.clientFinishedIsFirst = false
if err := hs.readFinished(nil); err != nil {
return err
}
} else {
// The client didn't include a session ticket, or it wasn't
// valid so we do a full handshake.
if err := hs.pickCipherSuite(); err != nil {
return err
}
if err := hs.doFullHandshake(); err != nil {
return err
}
if err := hs.establishKeys(); err != nil {
return err
}
if err := hs.readFinished(c.clientFinished[:]); err != nil {
return err
}
c.clientFinishedIsFirst = true
c.buffering = true
if err := hs.sendSessionTicket(); err != nil {
return err
}
if err := hs.sendFinished(nil); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
}
c.ekm = ekmFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random)
c.isHandshakeComplete.Store(true)
return nil
}
// readClientHello reads a ClientHello message and selects the protocol version.
func (c *Conn) readClientHello(ctx context.Context) (*clientHelloMsg, *echServerContext, error) {
// clientHelloMsg is included in the transcript, but we haven't initialized
// it yet. The respective handshake functions will record it themselves.
msg, err := c.readHandshake(nil)
if err != nil {
return nil, nil, err
}
clientHello, ok := msg.(*clientHelloMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return nil, nil, unexpectedMessageError(clientHello, msg)
}
// ECH processing has to be done before we do any other negotiation based on
// the contents of the client hello, since we may swap it out completely.
var ech *echServerContext
if len(clientHello.encryptedClientHello) != 0 {
echKeys := c.config.EncryptedClientHelloKeys
if c.config.GetEncryptedClientHelloKeys != nil {
echKeys, err = c.config.GetEncryptedClientHelloKeys(clientHelloInfo(ctx, c, clientHello))
if err != nil {
c.sendAlert(alertInternalError)
return nil, nil, err
}
}
clientHello, ech, err = c.processECHClientHello(clientHello, echKeys)
if err != nil {
return nil, nil, err
}
}
var configForClient *Config
originalConfig := c.config
if c.config.GetConfigForClient != nil {
chi := clientHelloInfo(ctx, c, clientHello)
if configForClient, err = c.config.GetConfigForClient(chi); err != nil {
c.sendAlert(alertInternalError)
return nil, nil, err
} else if configForClient != nil {
c.config = configForClient
}
}
c.ticketKeys = originalConfig.ticketKeys(configForClient)
clientVersions := clientHello.supportedVersions
if clientHello.vers >= VersionTLS13 && len(clientVersions) == 0 {
// RFC 8446 4.2.1 indicates when the supported_versions extension is not sent,
// compatible servers MUST negotiate TLS 1.2 or earlier if supported, even
// if the client legacy version is TLS 1.3 or later.
//
// Since we reject empty extensionSupportedVersions in the client hello unmarshal
// finding the supportedVersions empty indicates the extension was not present.
clientVersions = supportedVersionsFromMax(VersionTLS12)
} else if len(clientVersions) == 0 {
clientVersions = supportedVersionsFromMax(clientHello.vers)
}
c.vers, ok = c.config.mutualVersion(roleServer, clientVersions)
if !ok {
c.sendAlert(alertProtocolVersion)
return nil, nil, fmt.Errorf("tls: client offered only unsupported versions: %x", clientVersions)
}
c.haveVers = true
c.in.version = c.vers
c.out.version = c.vers
// This check reflects some odd specification implied behavior. Client-facing servers
// are supposed to reject hellos with outer ECH and inner ECH that offers 1.2, but
// backend servers are allowed to accept hellos with inner ECH that offer 1.2, since
// they cannot expect client-facing servers to behave properly. Since we act as both
// a client-facing and backend server, we only enforce 1.3 being negotiated if we
// saw a hello with outer ECH first. The spec probably should've made this an error,
// but it didn't, and this matches the boringssl behavior.
if c.vers != VersionTLS13 && (ech != nil && !ech.inner) {
c.sendAlert(alertIllegalParameter)
return nil, nil, errors.New("tls: Encrypted Client Hello cannot be used pre-TLS 1.3")
}
return clientHello, ech, nil
}
func (hs *serverHandshakeState) processClientHello() error {
c := hs.c
hs.hello = new(serverHelloMsg)
hs.hello.vers = c.vers
foundCompression := false
// We only support null compression, so check that the client offered it.
for _, compression := range hs.clientHello.compressionMethods {
if compression == compressionNone {
foundCompression = true
break
}
}
if !foundCompression {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: client does not support uncompressed connections")
}
hs.hello.random = make([]byte, 32)
serverRandom := hs.hello.random
// Downgrade protection canaries. See RFC 8446, Section 4.1.3.
maxVers := c.config.maxSupportedVersion(roleServer)
if maxVers >= VersionTLS12 && c.vers < maxVers || testingOnlyForceDowngradeCanary {
if c.vers == VersionTLS12 {
copy(serverRandom[24:], downgradeCanaryTLS12)
} else {
copy(serverRandom[24:], downgradeCanaryTLS11)
}
serverRandom = serverRandom[:24]
}
_, err := io.ReadFull(c.config.rand(), serverRandom)
if err != nil {
c.sendAlert(alertInternalError)
return err
}
if len(hs.clientHello.secureRenegotiation) != 0 {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: initial handshake had non-empty renegotiation extension")
}
hs.hello.extendedMasterSecret = hs.clientHello.extendedMasterSecret
hs.hello.secureRenegotiationSupported = hs.clientHello.secureRenegotiationSupported
hs.hello.compressionMethod = compressionNone
if len(hs.clientHello.serverName) > 0 {
c.serverName = hs.clientHello.serverName
}
selectedProto, err := negotiateALPN(c.config.NextProtos, hs.clientHello.alpnProtocols, false)
if err != nil {
c.sendAlert(alertNoApplicationProtocol)
return err
}
hs.hello.alpnProtocol = selectedProto
c.clientProtocol = selectedProto
hs.cert, err = c.config.getCertificate(clientHelloInfo(hs.ctx, c, hs.clientHello))
if err != nil {
if err == errNoCertificates {
c.sendAlert(alertUnrecognizedName)
} else {
c.sendAlert(alertInternalError)
}
return err
}
if hs.clientHello.scts {
hs.hello.scts = hs.cert.SignedCertificateTimestamps
}
hs.ecdheOk, err = supportsECDHE(c.config, c.vers, hs.clientHello.supportedCurves, hs.clientHello.supportedPoints)
if err != nil {
c.sendAlert(alertMissingExtension)
return err
}
if hs.ecdheOk && len(hs.clientHello.supportedPoints) > 0 {
// Although omitting the ec_point_formats extension is permitted, some
// old OpenSSL version will refuse to handshake if not present.
//
// Per RFC 4492, section 5.1.2, implementations MUST support the
// uncompressed point format. See golang.org/issue/31943.
hs.hello.supportedPoints = []uint8{pointFormatUncompressed}
}
if priv, ok := hs.cert.PrivateKey.(crypto.Signer); ok {
switch priv.Public().(type) {
case *ecdsa.PublicKey:
hs.ecSignOk = true
case ed25519.PublicKey:
hs.ecSignOk = true
case *rsa.PublicKey:
hs.rsaSignOk = true
default:
c.sendAlert(alertInternalError)
return fmt.Errorf("tls: unsupported signing key type (%T)", priv.Public())
}
}
if priv, ok := hs.cert.PrivateKey.(crypto.Decrypter); ok {
switch priv.Public().(type) {
case *rsa.PublicKey:
hs.rsaDecryptOk = true
default:
c.sendAlert(alertInternalError)
return fmt.Errorf("tls: unsupported decryption key type (%T)", priv.Public())
}
}
return nil
}
// negotiateALPN picks a shared ALPN protocol that both sides support in server
// preference order. If ALPN is not configured or the peer doesn't support it,
// it returns "" and no error.
func negotiateALPN(serverProtos, clientProtos []string, quic bool) (string, error) {
if len(serverProtos) == 0 || len(clientProtos) == 0 {
if quic && len(serverProtos) != 0 {
// RFC 9001, Section 8.1
return "", fmt.Errorf("tls: client did not request an application protocol")
}
return "", nil
}
var http11fallback bool
for _, s := range serverProtos {
for _, c := range clientProtos {
if s == c {
return s, nil
}
if s == "h2" && c == "http/1.1" {
http11fallback = true
}
}
}
// As a special case, let http/1.1 clients connect to h2 servers as if they
// didn't support ALPN. We used not to enforce protocol overlap, so over
// time a number of HTTP servers were configured with only "h2", but
// expected to accept connections from "http/1.1" clients. See Issue 46310.
if http11fallback {
return "", nil
}
return "", fmt.Errorf("tls: client requested unsupported application protocols (%s)", clientProtos)
}
// supportsECDHE returns whether ECDHE key exchanges can be used with this
// pre-TLS 1.3 client.
func supportsECDHE(c *Config, version uint16, supportedCurves []CurveID, supportedPoints []uint8) (bool, error) {
supportsCurve := false
for _, curve := range supportedCurves {
if c.supportsCurve(version, curve) {
supportsCurve = true
break
}
}
supportsPointFormat := false
offeredNonCompressedFormat := false
for _, pointFormat := range supportedPoints {
if pointFormat == pointFormatUncompressed {
supportsPointFormat = true
} else {
offeredNonCompressedFormat = true
}
}
// Per RFC 8422, Section 5.1.2, if the Supported Point Formats extension is
// missing, uncompressed points are supported. If supportedPoints is empty,
// the extension must be missing, as an empty extension body is rejected by
// the parser. See https://go.dev/issue/49126.
if len(supportedPoints) == 0 {
supportsPointFormat = true
} else if offeredNonCompressedFormat && !supportsPointFormat {
return false, errors.New("tls: client offered only incompatible point formats")
}
return supportsCurve && supportsPointFormat, nil
}
func (hs *serverHandshakeState) pickCipherSuite() error {
c := hs.c
preferenceList := c.config.cipherSuites(isAESGCMPreferred(hs.clientHello.cipherSuites))
hs.suite = selectCipherSuite(preferenceList, hs.clientHello.cipherSuites, hs.cipherSuiteOk)
if hs.suite == nil {
c.sendAlert(alertHandshakeFailure)
return fmt.Errorf("tls: no cipher suite supported by both client and server; client offered: %x",
hs.clientHello.cipherSuites)
}
c.cipherSuite = hs.suite.id
for _, id := range hs.clientHello.cipherSuites {
if id == TLS_FALLBACK_SCSV {
// The client is doing a fallback connection. See RFC 7507.
if hs.clientHello.vers < c.config.maxSupportedVersion(roleServer) {
c.sendAlert(alertInappropriateFallback)
return errors.New("tls: client using inappropriate protocol fallback")
}
break
}
}
return nil
}
func (hs *serverHandshakeState) cipherSuiteOk(c *cipherSuite) bool {
if c.flags&suiteECDHE != 0 {
if !hs.ecdheOk {
return false
}
if c.flags&suiteECSign != 0 {
if !hs.ecSignOk {
return false
}
} else if !hs.rsaSignOk {
return false
}
} else if !hs.rsaDecryptOk {
return false
}
if hs.c.vers < VersionTLS12 && c.flags&suiteTLS12 != 0 {
return false
}
return true
}
// checkForResumption reports whether we should perform resumption on this connection.
func (hs *serverHandshakeState) checkForResumption() error {
c := hs.c
if c.config.SessionTicketsDisabled {
return nil
}
var sessionState *SessionState
if c.config.UnwrapSession != nil {
ss, err := c.config.UnwrapSession(hs.clientHello.sessionTicket, c.connectionStateLocked())
if err != nil {
return err
}
if ss == nil {
return nil
}
sessionState = ss
} else {
plaintext := c.config.decryptTicket(hs.clientHello.sessionTicket, c.ticketKeys)
if plaintext == nil {
return nil
}
ss, err := ParseSessionState(plaintext)
if err != nil {
return nil
}
sessionState = ss
}
// TLS 1.2 tickets don't natively have a lifetime, but we want to avoid
// re-wrapping the same master secret in different tickets over and over for
// too long, weakening forward secrecy.
createdAt := time.Unix(int64(sessionState.createdAt), 0)
if c.config.time().Sub(createdAt) > maxSessionTicketLifetime {
return nil
}
// Never resume a session for a different TLS version.
if c.vers != sessionState.version {
return nil
}
cipherSuiteOk := false
// Check that the client is still offering the ciphersuite in the session.
for _, id := range hs.clientHello.cipherSuites {
if id == sessionState.cipherSuite {
cipherSuiteOk = true
break
}
}
if !cipherSuiteOk {
return nil
}
// Check that we also support the ciphersuite from the session.
suite := selectCipherSuite([]uint16{sessionState.cipherSuite},
c.config.supportedCipherSuites(), hs.cipherSuiteOk)
if suite == nil {
return nil
}
sessionHasClientCerts := len(sessionState.peerCertificates) != 0
needClientCerts := requiresClientCert(c.config.ClientAuth)
if needClientCerts && !sessionHasClientCerts {
return nil
}
if sessionHasClientCerts && c.config.ClientAuth == NoClientCert {
return nil
}
if sessionHasClientCerts && c.config.time().After(sessionState.peerCertificates[0].NotAfter) {
return nil
}
if sessionHasClientCerts && c.config.ClientAuth >= VerifyClientCertIfGiven &&
len(sessionState.verifiedChains) == 0 {
return nil
}
// RFC 7627, Section 5.3
if !sessionState.extMasterSecret && hs.clientHello.extendedMasterSecret {
return nil
}
if sessionState.extMasterSecret && !hs.clientHello.extendedMasterSecret {
// Aborting is somewhat harsh, but it's a MUST and it would indicate a
// weird downgrade in client capabilities.
return errors.New("tls: session supported extended_master_secret but client does not")
}
if !sessionState.extMasterSecret && fips140tls.Required() {
// FIPS 140-3 requires the use of Extended Master Secret.
return nil
}
c.peerCertificates = sessionState.peerCertificates
c.ocspResponse = sessionState.ocspResponse
c.scts = sessionState.scts
c.verifiedChains = sessionState.verifiedChains
c.extMasterSecret = sessionState.extMasterSecret
hs.sessionState = sessionState
hs.suite = suite
c.curveID = sessionState.curveID
c.didResume = true
return nil
}
func (hs *serverHandshakeState) doResumeHandshake() error {
c := hs.c
hs.hello.cipherSuite = hs.suite.id
c.cipherSuite = hs.suite.id
// We echo the client's session ID in the ServerHello to let it know
// that we're doing a resumption.
hs.hello.sessionId = hs.clientHello.sessionId
// We always send a new session ticket, even if it wraps the same master
// secret and it's potentially encrypted with the same key, to help the
// client avoid cross-connection tracking from a network observer.
hs.hello.ticketSupported = true
hs.finishedHash = newFinishedHash(c.vers, hs.suite)
hs.finishedHash.discardHandshakeBuffer()
if err := transcriptMsg(hs.clientHello, &hs.finishedHash); err != nil {
return err
}
if _, err := hs.c.writeHandshakeRecord(hs.hello, &hs.finishedHash); err != nil {
return err
}
if c.config.VerifyConnection != nil {
if err := c.config.VerifyConnection(c.connectionStateLocked()); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
hs.masterSecret = hs.sessionState.secret
return nil
}
func (hs *serverHandshakeState) doFullHandshake() error {
c := hs.c
if hs.clientHello.ocspStapling && len(hs.cert.OCSPStaple) > 0 {
hs.hello.ocspStapling = true
}
hs.hello.ticketSupported = hs.clientHello.ticketSupported && !c.config.SessionTicketsDisabled
hs.hello.cipherSuite = hs.suite.id
hs.finishedHash = newFinishedHash(hs.c.vers, hs.suite)
if c.config.ClientAuth == NoClientCert {
// No need to keep a full record of the handshake if client
// certificates won't be used.
hs.finishedHash.discardHandshakeBuffer()
}
if err := transcriptMsg(hs.clientHello, &hs.finishedHash); err != nil {
return err
}
if _, err := hs.c.writeHandshakeRecord(hs.hello, &hs.finishedHash); err != nil {
return err
}
certMsg := new(certificateMsg)
certMsg.certificates = hs.cert.Certificate
if _, err := hs.c.writeHandshakeRecord(certMsg, &hs.finishedHash); err != nil {
return err
}
if hs.hello.ocspStapling {
certStatus := new(certificateStatusMsg)
certStatus.response = hs.cert.OCSPStaple
if _, err := hs.c.writeHandshakeRecord(certStatus, &hs.finishedHash); err != nil {
return err
}
}
keyAgreement := hs.suite.ka(c.vers)
skx, err := keyAgreement.generateServerKeyExchange(c.config, hs.cert, hs.clientHello, hs.hello)
if err != nil {
c.sendAlert(alertHandshakeFailure)
return err
}
if skx != nil {
if len(skx.key) >= 3 && skx.key[0] == 3 /* named curve */ {
c.curveID = CurveID(binary.BigEndian.Uint16(skx.key[1:]))
}
if _, err := hs.c.writeHandshakeRecord(skx, &hs.finishedHash); err != nil {
return err
}
}
var certReq *certificateRequestMsg
if c.config.ClientAuth >= RequestClientCert {
// Request a client certificate
certReq = new(certificateRequestMsg)
certReq.certificateTypes = []byte{
byte(certTypeRSASign),
byte(certTypeECDSASign),
}
if c.vers >= VersionTLS12 {
certReq.hasSignatureAlgorithm = true
certReq.supportedSignatureAlgorithms = supportedSignatureAlgorithms(c.vers)
}
// An empty list of certificateAuthorities signals to
// the client that it may send any certificate in response
// to our request. When we know the CAs we trust, then
// we can send them down, so that the client can choose
// an appropriate certificate to give to us.
if c.config.ClientCAs != nil {
certReq.certificateAuthorities = c.config.ClientCAs.Subjects()
}
if _, err := hs.c.writeHandshakeRecord(certReq, &hs.finishedHash); err != nil {
return err
}
}
helloDone := new(serverHelloDoneMsg)
if _, err := hs.c.writeHandshakeRecord(helloDone, &hs.finishedHash); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
var pub crypto.PublicKey // public key for client auth, if any
msg, err := c.readHandshake(&hs.finishedHash)
if err != nil {
return err
}
// If we requested a client certificate, then the client must send a
// certificate message, even if it's empty.
if c.config.ClientAuth >= RequestClientCert {
certMsg, ok := msg.(*certificateMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(certMsg, msg)
}
if err := c.processCertsFromClient(Certificate{
Certificate: certMsg.certificates,
}); err != nil {
return err
}
if len(certMsg.certificates) != 0 {
pub = c.peerCertificates[0].PublicKey
}
msg, err = c.readHandshake(&hs.finishedHash)
if err != nil {
return err
}
}
if c.config.VerifyConnection != nil {
if err := c.config.VerifyConnection(c.connectionStateLocked()); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
// Get client key exchange
ckx, ok := msg.(*clientKeyExchangeMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(ckx, msg)
}
preMasterSecret, err := keyAgreement.processClientKeyExchange(c.config, hs.cert, ckx, c.vers)
if err != nil {
c.sendAlert(alertIllegalParameter)
return err
}
if hs.hello.extendedMasterSecret {
c.extMasterSecret = true
hs.masterSecret = extMasterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
hs.finishedHash.Sum())
} else {
if fips140tls.Required() {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: FIPS 140-3 requires the use of Extended Master Secret")
}
hs.masterSecret = masterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
hs.clientHello.random, hs.hello.random)
}
if err := c.config.writeKeyLog(keyLogLabelTLS12, hs.clientHello.random, hs.masterSecret); err != nil {
c.sendAlert(alertInternalError)
return err
}
// If we received a client cert in response to our certificate request message,
// the client will send us a certificateVerifyMsg immediately after the
// clientKeyExchangeMsg. This message is a digest of all preceding
// handshake-layer messages that is signed using the private key corresponding
// to the client's certificate. This allows us to verify that the client is in
// possession of the private key of the certificate.
if len(c.peerCertificates) > 0 {
// certificateVerifyMsg is included in the transcript, but not until
// after we verify the handshake signature, since the state before
// this message was sent is used.
msg, err = c.readHandshake(nil)
if err != nil {
return err
}
certVerify, ok := msg.(*certificateVerifyMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(certVerify, msg)
}
var sigType uint8
var sigHash crypto.Hash
if c.vers >= VersionTLS12 {
if !isSupportedSignatureAlgorithm(certVerify.signatureAlgorithm, certReq.supportedSignatureAlgorithms) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: client certificate used with invalid signature algorithm")
}
sigType, sigHash, err = typeAndHashFromSignatureScheme(certVerify.signatureAlgorithm)
if err != nil {
return c.sendAlert(alertInternalError)
}
} else {
sigType, sigHash, err = legacyTypeAndHashFromPublicKey(pub)
if err != nil {
c.sendAlert(alertIllegalParameter)
return err
}
}
signed := hs.finishedHash.hashForClientCertificate(sigType, sigHash)
if err := verifyHandshakeSignature(sigType, pub, sigHash, signed, certVerify.signature); err != nil {
c.sendAlert(alertDecryptError)
return errors.New("tls: invalid signature by the client certificate: " + err.Error())
}
if err := transcriptMsg(certVerify, &hs.finishedHash); err != nil {
return err
}
}
hs.finishedHash.discardHandshakeBuffer()
return nil
}
func (hs *serverHandshakeState) establishKeys() error {
c := hs.c
clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV :=
keysFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random, hs.suite.macLen, hs.suite.keyLen, hs.suite.ivLen)
var clientCipher, serverCipher any
var clientHash, serverHash hash.Hash
if hs.suite.aead == nil {
clientCipher = hs.suite.cipher(clientKey, clientIV, true /* for reading */)
clientHash = hs.suite.mac(clientMAC)
serverCipher = hs.suite.cipher(serverKey, serverIV, false /* not for reading */)
serverHash = hs.suite.mac(serverMAC)
} else {
clientCipher = hs.suite.aead(clientKey, clientIV)
serverCipher = hs.suite.aead(serverKey, serverIV)
}
c.in.prepareCipherSpec(c.vers, clientCipher, clientHash)
c.out.prepareCipherSpec(c.vers, serverCipher, serverHash)
return nil
}
func (hs *serverHandshakeState) readFinished(out []byte) error {
c := hs.c
if err := c.readChangeCipherSpec(); err != nil {
return err
}
// finishedMsg is included in the transcript, but not until after we
// check the client version, since the state before this message was
// sent is used during verification.
msg, err := c.readHandshake(nil)
if err != nil {
return err
}
clientFinished, ok := msg.(*finishedMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(clientFinished, msg)
}
verify := hs.finishedHash.clientSum(hs.masterSecret)
if len(verify) != len(clientFinished.verifyData) ||
subtle.ConstantTimeCompare(verify, clientFinished.verifyData) != 1 {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: client's Finished message is incorrect")
}
if err := transcriptMsg(clientFinished, &hs.finishedHash); err != nil {
return err
}
copy(out, verify)
return nil
}
func (hs *serverHandshakeState) sendSessionTicket() error {
if !hs.hello.ticketSupported {
return nil
}
c := hs.c
m := new(newSessionTicketMsg)
state := c.sessionState()
state.secret = hs.masterSecret
if hs.sessionState != nil {
// If this is re-wrapping an old key, then keep
// the original time it was created.
state.createdAt = hs.sessionState.createdAt
}
if c.config.WrapSession != nil {
var err error
m.ticket, err = c.config.WrapSession(c.connectionStateLocked(), state)
if err != nil {
return err
}
} else {
stateBytes, err := state.Bytes()
if err != nil {
return err
}
m.ticket, err = c.config.encryptTicket(stateBytes, c.ticketKeys)
if err != nil {
return err
}
}
if _, err := hs.c.writeHandshakeRecord(m, &hs.finishedHash); err != nil {
return err
}
return nil
}
func (hs *serverHandshakeState) sendFinished(out []byte) error {
c := hs.c
if err := c.writeChangeCipherRecord(); err != nil {
return err
}
finished := new(finishedMsg)
finished.verifyData = hs.finishedHash.serverSum(hs.masterSecret)
if _, err := hs.c.writeHandshakeRecord(finished, &hs.finishedHash); err != nil {
return err
}
copy(out, finished.verifyData)
return nil
}
// processCertsFromClient takes a chain of client certificates either from a
// certificateMsg message or a certificateMsgTLS13 message and verifies them.
func (c *Conn) processCertsFromClient(certificate Certificate) error {
certificates := certificate.Certificate
certs := make([]*x509.Certificate, len(certificates))
var err error
for i, asn1Data := range certificates {
if certs[i], err = x509.ParseCertificate(asn1Data); err != nil {
c.sendAlert(alertDecodeError)
return errors.New("tls: failed to parse client certificate: " + err.Error())
}
if certs[i].PublicKeyAlgorithm == x509.RSA {
n := certs[i].PublicKey.(*rsa.PublicKey).N.BitLen()
if max, ok := checkKeySize(n); !ok {
c.sendAlert(alertBadCertificate)
return fmt.Errorf("tls: client sent certificate containing RSA key larger than %d bits", max)
}
}
}
if len(certs) == 0 && requiresClientCert(c.config.ClientAuth) {
if c.vers == VersionTLS13 {
c.sendAlert(alertCertificateRequired)
} else {
c.sendAlert(alertHandshakeFailure)
}
return errors.New("tls: client didn't provide a certificate")
}
if c.config.ClientAuth >= VerifyClientCertIfGiven && len(certs) > 0 {
opts := x509.VerifyOptions{
Roots: c.config.ClientCAs,
CurrentTime: c.config.time(),
Intermediates: x509.NewCertPool(),
KeyUsages: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
}
for _, cert := range certs[1:] {
opts.Intermediates.AddCert(cert)
}
chains, err := certs[0].Verify(opts)
if err != nil {
var errCertificateInvalid x509.CertificateInvalidError
if errors.As(err, &x509.UnknownAuthorityError{}) {
c.sendAlert(alertUnknownCA)
} else if errors.As(err, &errCertificateInvalid) && errCertificateInvalid.Reason == x509.Expired {
c.sendAlert(alertCertificateExpired)
} else {
c.sendAlert(alertBadCertificate)
}
return &CertificateVerificationError{UnverifiedCertificates: certs, Err: err}
}
c.verifiedChains, err = fipsAllowedChains(chains)
if err != nil {
c.sendAlert(alertBadCertificate)
return &CertificateVerificationError{UnverifiedCertificates: certs, Err: err}
}
}
c.peerCertificates = certs
c.ocspResponse = certificate.OCSPStaple
c.scts = certificate.SignedCertificateTimestamps
if len(certs) > 0 {
switch certs[0].PublicKey.(type) {
case *ecdsa.PublicKey, *rsa.PublicKey, ed25519.PublicKey:
default:
c.sendAlert(alertUnsupportedCertificate)
return fmt.Errorf("tls: client certificate contains an unsupported public key of type %T", certs[0].PublicKey)
}
}
if c.config.VerifyPeerCertificate != nil {
if err := c.config.VerifyPeerCertificate(certificates, c.verifiedChains); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
return nil
}
func clientHelloInfo(ctx context.Context, c *Conn, clientHello *clientHelloMsg) *ClientHelloInfo {
supportedVersions := clientHello.supportedVersions
if len(clientHello.supportedVersions) == 0 {
supportedVersions = supportedVersionsFromMax(clientHello.vers)
}
return &ClientHelloInfo{
CipherSuites: clientHello.cipherSuites,
ServerName: clientHello.serverName,
SupportedCurves: clientHello.supportedCurves,
SupportedPoints: clientHello.supportedPoints,
SignatureSchemes: clientHello.supportedSignatureAlgorithms,
SupportedProtos: clientHello.alpnProtocols,
SupportedVersions: supportedVersions,
You can’t perform that action at this time.