aboutsummaryrefslogtreecommitdiffstats
path: root/ssl/d1_srvr.c
blob: bc875b53c9a0d9b4d97a83897d715cafe97ef2d1 (plain) (blame)
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
/* ssl/d1_srvr.c */
/*
 * DTLS implementation written by Nagendra Modadugu
 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
 */
/* ====================================================================
 * Copyright (c) 1999-2007 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include "ssl_locl.h"
#include <openssl/buffer.h>
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/md5.h>
#include <openssl/bn.h>
#ifndef OPENSSL_NO_DH
# include <openssl/dh.h>
#endif

static const SSL_METHOD *dtls1_get_server_method(int ver);
static int dtls1_send_hello_verify_request(SSL *s);

static const SSL_METHOD *dtls1_get_server_method(int ver)
{
    if (ver == DTLS_ANY_VERSION)
        return DTLS_server_method();
    else if (ver == DTLS1_VERSION)
        return DTLSv1_server_method();
    else if (ver == DTLS1_2_VERSION)
        return DTLSv1_2_server_method();
    else
        return NULL;
}

IMPLEMENT_dtls1_meth_func(DTLS1_VERSION,
                          DTLSv1_server_method,
                          dtls1_accept,
                          ssl_undefined_function,
                          dtls1_get_server_method, DTLSv1_enc_data)

IMPLEMENT_dtls1_meth_func(DTLS1_2_VERSION,
                          DTLSv1_2_server_method,
                          dtls1_accept,
                          ssl_undefined_function,
                          dtls1_get_server_method, DTLSv1_2_enc_data)

IMPLEMENT_dtls1_meth_func(DTLS_ANY_VERSION,
                          DTLS_server_method,
                          dtls1_accept,
                          ssl_undefined_function,
                          dtls1_get_server_method, DTLSv1_2_enc_data)

int dtls1_accept(SSL *s)
{
    BUF_MEM *buf;
    unsigned long Time = (unsigned long)time(NULL);
    void (*cb) (const SSL *ssl, int type, int val) = NULL;
    unsigned long alg_k;
    int ret = -1;
    int new_state, state, skip = 0;
    int listen;
#ifndef OPENSSL_NO_SCTP
    unsigned char sctpauthkey[64];
    char labelbuffer[sizeof(DTLS1_SCTP_AUTH_LABEL)];
#endif

    RAND_add(&Time, sizeof(Time), 0);
    ERR_clear_error();
    clear_sys_error();

    if (s->info_callback != NULL)
        cb = s->info_callback;
    else if (s->ctx->info_callback != NULL)
        cb = s->ctx->info_callback;

    listen = s->d1->listen;

    /* init things to blank */
    s->in_handshake++;
    if (!SSL_in_init(s) || SSL_in_before(s))
        SSL_clear(s);

    s->d1->listen = listen;
#ifndef OPENSSL_NO_SCTP
    /*
     * Notify SCTP BIO socket to enter handshake mode and prevent stream
     * identifier other than 0. Will be ignored if no SCTP is used.
     */
    BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
             s->in_handshake, NULL);
#endif

    if (s->cert == NULL) {
        SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_NO_CERTIFICATE_SET);
        return (-1);
    }
#ifndef OPENSSL_NO_HEARTBEATS
    /*
     * If we're awaiting a HeartbeatResponse, pretend we already got and
     * don't await it anymore, because Heartbeats don't make sense during
     * handshakes anyway.
     */
    if (s->tlsext_hb_pending) {
        dtls1_stop_timer(s);
        s->tlsext_hb_pending = 0;
        s->tlsext_hb_seq++;
    }
#endif

    for (;;) {
        state = s->state;

        switch (s->state) {
        case SSL_ST_RENEGOTIATE:
            s->renegotiate = 1;
            /* s->state=SSL_ST_ACCEPT; */

        case SSL_ST_BEFORE:
        case SSL_ST_ACCEPT:
        case SSL_ST_BEFORE | SSL_ST_ACCEPT:
        case SSL_ST_OK | SSL_ST_ACCEPT:

            s->server = 1;
            if (cb != NULL)
                cb(s, SSL_CB_HANDSHAKE_START, 1);

            if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
                SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
                return -1;
            }
            s->type = SSL_ST_ACCEPT;

            if (s->init_buf == NULL) {
                if ((buf = BUF_MEM_new()) == NULL) {
                    ret = -1;
                    s->state = SSL_ST_ERR;
                    goto end;
                }
                if (!BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) {
                    BUF_MEM_free(buf);
                    ret = -1;
                    s->state = SSL_ST_ERR;
                    goto end;
                }
                s->init_buf = buf;
            }

            if (!ssl3_setup_buffers(s)) {
                ret = -1;
                s->state = SSL_ST_ERR;
                goto end;
            }

            s->init_num = 0;
            s->d1->change_cipher_spec_ok = 0;
            /*
             * Should have been reset by ssl3_get_finished, too.
             */
            s->s3->change_cipher_spec = 0;

            if (s->state != SSL_ST_RENEGOTIATE) {
                /*
                 * Ok, we now need to push on a buffering BIO so that the
                 * output is sent in a way that TCP likes :-) ...but not with
                 * SCTP :-)
                 */
#ifndef OPENSSL_NO_SCTP
                if (!BIO_dgram_is_sctp(SSL_get_wbio(s)))
#endif
                    if (!ssl_init_wbio_buffer(s, 1)) {
                        ret = -1;
                        s->state = SSL_ST_ERR;
                        goto end;
                    }

                ssl3_init_finished_mac(s);
                s->state = SSL3_ST_SR_CLNT_HELLO_A;
                s->ctx->stats.sess_accept++;
            } else if (!s->s3->send_connection_binding &&
                       !(s->options &
                         SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)) {
                /*
                 * Server attempting to renegotiate with client that doesn't
                 * support secure renegotiation.
                 */
                SSLerr(SSL_F_DTLS1_ACCEPT,
                       SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
                ret = -1;
                s->state = SSL_ST_ERR;
                goto end;
            } else {
                /*
                 * s->state == SSL_ST_RENEGOTIATE, we will just send a
                 * HelloRequest
                 */
                s->ctx->stats.sess_accept_renegotiate++;
                s->state = SSL3_ST_SW_HELLO_REQ_A;
            }

            break;

        case SSL3_ST_SW_HELLO_REQ_A:
        case SSL3_ST_SW_HELLO_REQ_B:

            s->shutdown = 0;
            dtls1_clear_sent_buffer(s);
            dtls1_start_timer(s);
            ret = ssl3_send_hello_request(s);
            if (ret <= 0)
                goto end;
            s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;
            s->state = SSL3_ST_SW_FLUSH;
            s->init_num = 0;

            ssl3_init_finished_mac(s);
            break;

        case SSL3_ST_SW_HELLO_REQ_C:
            s->state = SSL_ST_OK;
            break;

        case SSL3_ST_SR_CLNT_HELLO_A:
        case SSL3_ST_SR_CLNT_HELLO_B:
        case SSL3_ST_SR_CLNT_HELLO_C:

            s->shutdown = 0;
            ret = ssl3_get_client_hello(s);
            if (ret <= 0)
                goto end;
            dtls1_stop_timer(s);

            if (ret == 1 && (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE))
                s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A;
            else
                s->state = SSL3_ST_SW_SRVR_HELLO_A;

            s->init_num = 0;

            /*
             * Reflect ClientHello sequence to remain stateless while
             * listening
             */
            if (listen) {
                memcpy(s->s3->write_sequence, s->s3->read_sequence,
                       sizeof(s->s3->write_sequence));
            }

            /* If we're just listening, stop here */
            if (listen && s->state == SSL3_ST_SW_SRVR_HELLO_A) {
                ret = 2;
                s->d1->listen = 0;
                /*
                 * Set expected sequence numbers to continue the handshake.
                 */
                s->d1->handshake_read_seq = 2;
                s->d1->handshake_write_seq = 1;
                s->d1->next_handshake_write_seq = 1;
                goto end;
            }

            break;

        case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A:
        case DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B:

            ret = dtls1_send_hello_verify_request(s);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_FLUSH;
            s->s3->tmp.next_state = SSL3_ST_SR_CLNT_HELLO_A;

            /* HelloVerifyRequest resets Finished MAC */
            if (s->version != DTLS1_BAD_VER)
                ssl3_init_finished_mac(s);
            break;

#ifndef OPENSSL_NO_SCTP
        case DTLS1_SCTP_ST_SR_READ_SOCK:

            if (BIO_dgram_sctp_msg_waiting(SSL_get_rbio(s))) {
                s->s3->in_read_app_data = 2;
                s->rwstate = SSL_READING;
                BIO_clear_retry_flags(SSL_get_rbio(s));
                BIO_set_retry_read(SSL_get_rbio(s));
                ret = -1;
                goto end;
            }

            s->state = SSL3_ST_SR_FINISHED_A;
            break;

        case DTLS1_SCTP_ST_SW_WRITE_SOCK:
            ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
            if (ret < 0)
                goto end;

            if (ret == 0) {
                if (s->d1->next_state != SSL_ST_OK) {
                    s->s3->in_read_app_data = 2;
                    s->rwstate = SSL_READING;
                    BIO_clear_retry_flags(SSL_get_rbio(s));
                    BIO_set_retry_read(SSL_get_rbio(s));
                    ret = -1;
                    goto end;
                }
            }

            s->state = s->d1->next_state;
            break;
#endif

        case SSL3_ST_SW_SRVR_HELLO_A:
        case SSL3_ST_SW_SRVR_HELLO_B:
            s->renegotiate = 2;
            dtls1_start_timer(s);
            ret = ssl3_send_server_hello(s);
            if (ret <= 0)
                goto end;

            if (s->hit) {
#ifndef OPENSSL_NO_SCTP
                /*
                 * Add new shared key for SCTP-Auth, will be ignored if no
                 * SCTP used.
                 */
                snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
                         DTLS1_SCTP_AUTH_LABEL);

                if (SSL_export_keying_material(s, sctpauthkey,
                        sizeof(sctpauthkey), labelbuffer,
                        sizeof(labelbuffer), NULL, 0, 0) <= 0) {
                    ret = -1;
                    s->state = SSL_ST_ERR;
                    goto end;
                }

                BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
                         sizeof(sctpauthkey), sctpauthkey);
#endif
#ifndef OPENSSL_NO_TLSEXT
                if (s->tlsext_ticket_expected)
                    s->state = SSL3_ST_SW_SESSION_TICKET_A;
                else
                    s->state = SSL3_ST_SW_CHANGE_A;
#else
                s->state = SSL3_ST_SW_CHANGE_A;
#endif
            } else
                s->state = SSL3_ST_SW_CERT_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_CERT_A:
        case SSL3_ST_SW_CERT_B:
            /* Check if it is anon DH or normal PSK */
            if (!(s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL)
                && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
                dtls1_start_timer(s);
                ret = ssl3_send_server_certificate(s);
                if (ret <= 0)
                    goto end;
#ifndef OPENSSL_NO_TLSEXT
                if (s->tlsext_status_expected)
                    s->state = SSL3_ST_SW_CERT_STATUS_A;
                else
                    s->state = SSL3_ST_SW_KEY_EXCH_A;
            } else {
                skip = 1;
                s->state = SSL3_ST_SW_KEY_EXCH_A;
            }
#else
            } else
                skip = 1;

            s->state = SSL3_ST_SW_KEY_EXCH_A;
#endif
            s->init_num = 0;
            break;

        case SSL3_ST_SW_KEY_EXCH_A:
        case SSL3_ST_SW_KEY_EXCH_B:
            alg_k = s->s3->tmp.new_cipher->algorithm_mkey;

            /*
             * clear this, it may get reset by
             * send_server_key_exchange
             */
            s->s3->tmp.use_rsa_tmp = 0;

            /*
             * only send if a DH key exchange or RSA but we have a sign only
             * certificate
             */
            if (0
                /*
                 * PSK: send ServerKeyExchange if PSK identity hint if
                 * provided
                 */
#ifndef OPENSSL_NO_PSK
                || ((alg_k & SSL_kPSK) && s->ctx->psk_identity_hint)
#endif
                || (alg_k & SSL_kDHE)
                || (alg_k & SSL_kEECDH)
                || ((alg_k & SSL_kRSA)
                    && (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
                        || (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher)
                            && EVP_PKEY_size(s->cert->pkeys
                                             [SSL_PKEY_RSA_ENC].privatekey) *
                            8 > SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher)
                        )
                    )
                )
                ) {
                dtls1_start_timer(s);
                ret = ssl3_send_server_key_exchange(s);
                if (ret <= 0)
                    goto end;
            } else
                skip = 1;

            s->state = SSL3_ST_SW_CERT_REQ_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_CERT_REQ_A:
        case SSL3_ST_SW_CERT_REQ_B:
            if (                /* don't request cert unless asked for it: */
                   !(s->verify_mode & SSL_VERIFY_PEER) ||
                   /*
                    * if SSL_VERIFY_CLIENT_ONCE is set, don't request cert
                    * during re-negotiation:
                    */
                   ((s->session->peer != NULL) &&
                    (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)) ||
                   /*
                    * never request cert in anonymous ciphersuites (see
                    * section "Certificate request" in SSL 3 drafts and in
                    * RFC 2246):
                    */
                   ((s->s3->tmp.new_cipher->algorithm_auth & SSL_aNULL) &&
                    /*
                     * ... except when the application insists on
                     * verification (against the specs, but s3_clnt.c accepts
                     * this for SSL 3)
                     */
                    !(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) ||
                   /*
                    * never request cert in Kerberos ciphersuites
                    */
                   (s->s3->tmp.new_cipher->algorithm_auth & SSL_aKRB5)
                   /*
                    * With normal PSK Certificates and Certificate Requests
                    * are omitted
                    */
                   || (s->s3->tmp.new_cipher->algorithm_mkey & SSL_kPSK)) {
                /* no cert request */
                skip = 1;
                s->s3->tmp.cert_request = 0;
                s->state = SSL3_ST_SW_SRVR_DONE_A;
#ifndef OPENSSL_NO_SCTP
                if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
                    s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
                    s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
                }
#endif
            } else {
                s->s3->tmp.cert_request = 1;
                dtls1_start_timer(s);
                ret = ssl3_send_certificate_request(s);
                if (ret <= 0)
                    goto end;
#ifndef NETSCAPE_HANG_BUG
                s->state = SSL3_ST_SW_SRVR_DONE_A;
# ifndef OPENSSL_NO_SCTP
                if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
                    s->d1->next_state = SSL3_ST_SW_SRVR_DONE_A;
                    s->state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
                }
# endif
#else
                s->state = SSL3_ST_SW_FLUSH;
                s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
# ifndef OPENSSL_NO_SCTP
                if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
                    s->d1->next_state = s->s3->tmp.next_state;
                    s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
                }
# endif
#endif
                s->init_num = 0;
            }
            break;

        case SSL3_ST_SW_SRVR_DONE_A:
        case SSL3_ST_SW_SRVR_DONE_B:
            dtls1_start_timer(s);
            ret = ssl3_send_server_done(s);
            if (ret <= 0)
                goto end;
            s->s3->tmp.next_state = SSL3_ST_SR_CERT_A;
            s->state = SSL3_ST_SW_FLUSH;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_FLUSH:
            s->rwstate = SSL_WRITING;
            if (BIO_flush(s->wbio) <= 0) {
                /*
                 * If the write error was fatal, stop trying
                 */
                if (!BIO_should_retry(s->wbio)) {
                    s->rwstate = SSL_NOTHING;
                    s->state = s->s3->tmp.next_state;
                }

                ret = -1;
                goto end;
            }
            s->rwstate = SSL_NOTHING;
            s->state = s->s3->tmp.next_state;
            break;

        case SSL3_ST_SR_CERT_A:
        case SSL3_ST_SR_CERT_B:
            if (s->s3->tmp.cert_request) {
                ret = ssl3_get_client_certificate(s);
                if (ret <= 0)
                    goto end;
            }
            s->init_num = 0;
            s->state = SSL3_ST_SR_KEY_EXCH_A;
            break;

        case SSL3_ST_SR_KEY_EXCH_A:
        case SSL3_ST_SR_KEY_EXCH_B:
            ret = ssl3_get_client_key_exchange(s);
            if (ret <= 0)
                goto end;
#ifndef OPENSSL_NO_SCTP
            /*
             * Add new shared key for SCTP-Auth, will be ignored if no SCTP
             * used.
             */
            snprintf((char *)labelbuffer, sizeof(DTLS1_SCTP_AUTH_LABEL),
                     DTLS1_SCTP_AUTH_LABEL);

            if (SSL_export_keying_material(s, sctpauthkey,
                                       sizeof(sctpauthkey), labelbuffer,
                                       sizeof(labelbuffer), NULL, 0, 0) <= 0) {
                ret = -1;
                s->state = SSL_ST_ERR;
                goto end;
            }

            BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY,
                     sizeof(sctpauthkey), sctpauthkey);
#endif

            s->state = SSL3_ST_SR_CERT_VRFY_A;
            s->init_num = 0;

            if (ret == 2) {
                /*
                 * For the ECDH ciphersuites when the client sends its ECDH
                 * pub key in a certificate, the CertificateVerify message is
                 * not sent.
                 */
                s->state = SSL3_ST_SR_FINISHED_A;
                s->init_num = 0;
            } else if (SSL_USE_SIGALGS(s)) {
                s->state = SSL3_ST_SR_CERT_VRFY_A;
                s->init_num = 0;
                if (!s->session->peer)
                    break;
                /*
                 * For sigalgs freeze the handshake buffer at this point and
                 * digest cached records.
                 */
                if (!s->s3->handshake_buffer) {
                    SSLerr(SSL_F_DTLS1_ACCEPT, ERR_R_INTERNAL_ERROR);
                    s->state = SSL_ST_ERR;
                    return -1;
                }
                s->s3->flags |= TLS1_FLAGS_KEEP_HANDSHAKE;
                if (!ssl3_digest_cached_records(s)) {
                    s->state = SSL_ST_ERR;
                    return -1;
                }
            } else {
                s->state = SSL3_ST_SR_CERT_VRFY_A;
                s->init_num = 0;

                /*
                 * We need to get hashes here so if there is a client cert,
                 * it can be verified
                 */
                s->method->ssl3_enc->cert_verify_mac(s,
                                                     NID_md5,
                                                     &(s->s3->
                                                       tmp.cert_verify_md
                                                       [0]));
                s->method->ssl3_enc->cert_verify_mac(s, NID_sha1,
                                                     &(s->s3->
                                                       tmp.cert_verify_md
                                                       [MD5_DIGEST_LENGTH]));
            }
            break;

        case SSL3_ST_SR_CERT_VRFY_A:
        case SSL3_ST_SR_CERT_VRFY_B:
            ret = ssl3_get_cert_verify(s);
            if (ret <= 0)
                goto end;
#ifndef OPENSSL_NO_SCTP
            if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
                state == SSL_ST_RENEGOTIATE)
                s->state = DTLS1_SCTP_ST_SR_READ_SOCK;
            else
#endif
                s->state = SSL3_ST_SR_FINISHED_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SR_FINISHED_A:
        case SSL3_ST_SR_FINISHED_B:
            /*
             * Enable CCS. Receiving a CCS clears the flag, so make
             * sure not to re-enable it to ban duplicates. This *should* be the
             * first time we have received one - but we check anyway to be
             * cautious.
             * s->s3->change_cipher_spec is set when a CCS is
             * processed in d1_pkt.c, and remains set until
             * the client's Finished message is read.
             */
            if (!s->s3->change_cipher_spec)
                s->d1->change_cipher_spec_ok = 1;
            ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
                                    SSL3_ST_SR_FINISHED_B);
            if (ret <= 0)
                goto end;
            dtls1_stop_timer(s);
            if (s->hit)
                s->state = SSL_ST_OK;
#ifndef OPENSSL_NO_TLSEXT
            else if (s->tlsext_ticket_expected)
                s->state = SSL3_ST_SW_SESSION_TICKET_A;
#endif
            else
                s->state = SSL3_ST_SW_CHANGE_A;
            s->init_num = 0;
            break;

#ifndef OPENSSL_NO_TLSEXT
        case SSL3_ST_SW_SESSION_TICKET_A:
        case SSL3_ST_SW_SESSION_TICKET_B:
            ret = ssl3_send_newsession_ticket(s);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_CHANGE_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_CERT_STATUS_A:
        case SSL3_ST_SW_CERT_STATUS_B:
            ret = ssl3_send_cert_status(s);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_KEY_EXCH_A;
            s->init_num = 0;
            break;

#endif

        case SSL3_ST_SW_CHANGE_A:
        case SSL3_ST_SW_CHANGE_B:

            s->session->cipher = s->s3->tmp.new_cipher;
            if (!s->method->ssl3_enc->setup_key_block(s)) {
                ret = -1;
                s->state = SSL_ST_ERR;
                goto end;
            }

            ret = dtls1_send_change_cipher_spec(s,
                                                SSL3_ST_SW_CHANGE_A,
                                                SSL3_ST_SW_CHANGE_B);

            if (ret <= 0)
                goto end;

#ifndef OPENSSL_NO_SCTP
            if (!s->hit) {
                /*
                 * Change to new shared key of SCTP-Auth, will be ignored if
                 * no SCTP used.
                 */
                BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
                         0, NULL);
            }
#endif

            s->state = SSL3_ST_SW_FINISHED_A;
            s->init_num = 0;

            if (!s->method->ssl3_enc->change_cipher_state(s,
                                                          SSL3_CHANGE_CIPHER_SERVER_WRITE))
            {
                ret = -1;
                s->state = SSL_ST_ERR;
                goto end;
            }

            dtls1_reset_seq_numbers(s, SSL3_CC_WRITE);
            break;

        case SSL3_ST_SW_FINISHED_A:
        case SSL3_ST_SW_FINISHED_B:
            ret = ssl3_send_finished(s,
                                     SSL3_ST_SW_FINISHED_A,
                                     SSL3_ST_SW_FINISHED_B,
                                     s->method->
                                     ssl3_enc->server_finished_label,
                                     s->method->
                                     ssl3_enc->server_finished_label_len);
            if (ret <= 0)
                goto end;
            s->state = SSL3_ST_SW_FLUSH;
            if (s->hit) {
                s->s3->tmp.next_state = SSL3_ST_SR_FINISHED_A;

#ifndef OPENSSL_NO_SCTP
                /*
                 * Change to new shared key of SCTP-Auth, will be ignored if
                 * no SCTP used.
                 */
                BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY,
                         0, NULL);
#endif
            } else {
                s->s3->tmp.next_state = SSL_ST_OK;
#ifndef OPENSSL_NO_SCTP
                if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
                    s->d1->next_state = s->s3->tmp.next_state;
                    s->s3->tmp.next_state = DTLS1_SCTP_ST_SW_WRITE_SOCK;
                }
#endif
            }
            s->init_num = 0;
            break;

        case SSL_ST_OK:
            /* clean a few things up */
            ssl3_cleanup_key_block(s);

#if 0
            BUF_MEM_free(s->init_buf);
            s->init_buf = NULL;
#endif

            /* remove buffering on output */
            ssl_free_wbio_buffer(s);

            s->init_num = 0;

            if (s->renegotiate == 2) { /* skipped if we just sent a
                                        * HelloRequest */
                s->renegotiate = 0;
                s->new_session = 0;

                ssl_update_cache(s, SSL_SESS_CACHE_SERVER);

                s->ctx->stats.sess_accept_good++;
                /* s->server=1; */
                s->handshake_func = dtls1_accept;

                if (cb != NULL)
                    cb(s, SSL_CB_HANDSHAKE_DONE, 1);
            }

            ret = 1;

            /* done handshaking, next message is client hello */
            s->d1->handshake_read_seq = 0;
            /* next message is server hello */
            s->d1->handshake_write_seq = 0;
            s->d1->next_handshake_write_seq = 0;
            dtls1_clear_received_buffer(s);
            goto end;
            /* break; */

        case SSL_ST_ERR:
        default:
            SSLerr(SSL_F_DTLS1_ACCEPT, SSL_R_UNKNOWN_STATE);
            ret = -1;
            goto end;
            /* break; */
        }

        if (!s->s3->tmp.reuse_message && !skip) {
            if (s->debug) {
                if ((ret = BIO_flush(s->wbio)) <= 0)
                    goto end;
            }

            if ((cb != NULL) && (s->state != state)) {
                new_state = s->state;
                s->state = state;
                cb(s, SSL_CB_ACCEPT_LOOP, 1);
                s->state = new_state;
            }
        }
        skip = 0;
    }
 end:
    /* BIO_flush(s->wbio); */

    s->in_handshake--;
#ifndef OPENSSL_NO_SCTP
    /*
     * Notify SCTP BIO socket to leave handshake mode and prevent stream
     * identifier other than 0. Will be ignored if no SCTP is used.
     */
    BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
             s->in_handshake, NULL);
#endif

    if (cb != NULL)
        cb(s, SSL_CB_ACCEPT_EXIT, ret);
    return (ret);
}

int dtls1_send_hello_verify_request(SSL *s)
{
    unsigned int msg_len;
    unsigned char *msg, *buf, *p;

    if (s->state == DTLS1_ST_SW_HELLO_VERIFY_REQUEST_A) {
        buf = (unsigned char *)s->init_buf->data;

        msg = p = &(buf[DTLS1_HM_HEADER_LENGTH]);
        /* Always use DTLS 1.0 version: see RFC 6347 */
        *(p++) = DTLS1_VERSION >> 8;
        *(p++) = DTLS1_VERSION & 0xFF;

        if (s->ctx->app_gen_cookie_cb == NULL ||
            s->ctx->app_gen_cookie_cb(s, s->d1->cookie,
                                      &(s->d1->cookie_len)) == 0) {
            SSLerr(SSL_F_DTLS1_SEND_HELLO_VERIFY_REQUEST,
                   ERR_R_INTERNAL_ERROR);
            s->state = SSL_ST_ERR;
            return 0;
        }

        *(p++) = (unsigned char)s->d1->cookie_len;
        memcpy(p, s->d1->cookie, s->d1->cookie_len);
        p += s->d1->cookie_len;
        msg_len = p - msg;

        dtls1_set_message_header(s, buf,
                                 DTLS1_MT_HELLO_VERIFY_REQUEST, msg_len, 0,
                                 msg_len);

        s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B;
        /* number of bytes to write */
        s->init_num = p - buf;
        s->init_off = 0;
    }

    /* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */
    return (dtls1_do_write(s, SSL3_RT_HANDSHAKE));
}