/* 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;

                    }

                if (!ssl3_init_finished_mac(s)) {

                    ret = -1;

                    s->state = SSL_ST_ERR;

                    goto end;

                }

                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;

            if (!ssl3_init_finished_mac(s)) {

                ret = -1;

                s->state = SSL_ST_ERR;

                goto end;

            }

            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;

            /* 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)

                if (!ssl3_init_finished_mac(s)) {

                    ret = -1;

                    s->state = SSL_ST_ERR;

                    goto end;

                }

            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;

            }