openssl/ssl/s3_srvr.c

/* ssl/s3_srvr.c -*- mode:C; c-file-style: "eay" -*- */
/* 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.]
 */
/* ====================================================================
 * Copyright (c) 1998-2007 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 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
 *
 * Portions of the attached software ("Contribution") are developed by
 * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
 *
 * The Contribution is licensed pursuant to the OpenSSL open source
 * license provided above.
 *
 * ECC cipher suite support in OpenSSL originally written by
 * Vipul Gupta and Sumit Gupta of Sun Microsystems Laboratories.
 *
 */
/* ====================================================================
 * Copyright 2005 Nokia. All rights reserved.
 *
 * The portions of the attached software ("Contribution") is developed by
 * Nokia Corporation and is licensed pursuant to the OpenSSL open source
 * license.
 *
 * The Contribution, originally written by Mika Kousa and Pasi Eronen of
 * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
 * support (see RFC 4279) to OpenSSL.
 *
 * No patent licenses or other rights except those expressly stated in
 * the OpenSSL open source license shall be deemed granted or received
 * expressly, by implication, estoppel, or otherwise.
 *
 * No assurances are provided by Nokia that the Contribution does not
 * infringe the patent or other intellectual property rights of any third
 * party or that the license provides you with all the necessary rights
 * to make use of the Contribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
 * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
 * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
 * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
 * OTHERWISE.
 */


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

static STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s, unsigned char *p,
    int num, STACK_OF(SSL_CIPHER) **skp, int sslv2format);


#ifndef OPENSSL_NO_SRP
static int ssl_check_srp_ext_ClientHello(SSL *s, int *al)
{
    int ret = SSL_ERROR_NONE;

    *al = SSL_AD_UNRECOGNIZED_NAME;

    if ((s->s3->tmp.new_cipher->algorithm_mkey & SSL_kSRP) &&
        (s->srp_ctx.TLS_ext_srp_username_callback != NULL)) {
        if (s->srp_ctx.login == NULL) {
            /*
             * RFC 5054 says SHOULD reject, we do so if There is no srp
             * login name
             */
            ret = SSL3_AL_FATAL;
            *al = SSL_AD_UNKNOWN_PSK_IDENTITY;
        } else {
            ret = SSL_srp_server_param_with_username(s, al);
        }
    }
    return ret;
}
#endif

int ssl3_accept(SSL *s)
{
    BUF_MEM *buf;
    unsigned long alg_k, Time = (unsigned long)time(NULL);
    void (*cb) (const SSL *ssl, int type, int val) = NULL;
    int ret = -1;
    int new_state, state, skip = 0;

    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;

    /* init things to blank */
    s->in_handshake++;
    if (!SSL_in_init(s) || SSL_in_before(s)) {
        if (!SSL_clear(s))
            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) {
        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 >> 8 != 3) && s->version != TLS_ANY_VERSION) {
                SSLerr(SSL_F_SSL3_ACCEPT, ERR_R_INTERNAL_ERROR);
                s->state = SSL_ST_ERR;
                return -1;
            }

            if (!ssl_security(s, SSL_SECOP_VERSION, 0, s->version, NULL)) {
                SSLerr(SSL_F_SSL3_ACCEPT, SSL_R_VERSION_TOO_LOW);
                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->s3->flags &= ~TLS1_FLAGS_SKIP_CERT_VERIFY;
            /*
             * 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 :-)
                 */
                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_SSL3_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;
            ret = ssl3_send_hello_request(s);
            if (ret <= 0)
                goto end;
            s->s3->tmp.next_state = SSL3_ST_SW_HELLO_REQ_C;
            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:

            ret = ssl3_get_client_hello(s);
            if (ret <= 0)
                goto end;
#ifndef OPENSSL_NO_SRP
            s->state = SSL3_ST_SR_CLNT_HELLO_D;
        case SSL3_ST_SR_CLNT_HELLO_D:
            {
                int al;
                if ((ret = ssl_check_srp_ext_ClientHello(s, &al)) < 0) {
                    /*
                     * callback indicates firther work to be done
                     */
                    s->rwstate = SSL_X509_LOOKUP;
                    goto end;
                }
                if (ret != SSL_ERROR_NONE) {
                    ssl3_send_alert(s, SSL3_AL_FATAL, al);
                    /*
                     * This is not really an error but the only means to for
                     * a client to detect whether srp is supported.
                     */
                    if (al != TLS1_AD_UNKNOWN_PSK_IDENTITY)
                        SSLerr(SSL_F_SSL3_ACCEPT, SSL_R_CLIENTHELLO_TLSEXT);
                    ret = SSL_TLSEXT_ERR_ALERT_FATAL;
                    ret = -1;
                    s->state = SSL_ST_ERR;
                    goto end;
                }
            }
#endif

            s->renegotiate = 2;
            s->state = SSL3_ST_SW_SRVR_HELLO_A;
            s->init_num = 0;
            break;

        case SSL3_ST_SW_SRVR_HELLO_A:
        case SSL3_ST_SW_SRVR_HELLO_B:
            ret = ssl3_send_server_hello(s);
            if (ret <= 0)
                goto end;

            if (s->hit) {
                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_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 anon ECDH, */
            /* normal PSK or SRP */
            if (!(s->s3->tmp.new_cipher->algorithm_auth &
                 (SSL_aNULL | SSL_aSRP | SSL_aPSK))) {
                ret = ssl3_send_server_certificate(s);
                if (ret <= 0)
                    goto end;

                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;
            }
            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, fortezza or RSA but we have a
             * sign only certificate PSK: may send PSK identity hints For
             * ECC ciphersuites, we send a serverKeyExchange message only if
             * the cipher suite is either ECDH-anon or ECDHE. In other cases,
             * the server certificate contains the server's public key for
             * key exchange.
             */
            if (0
                /*
                 * PSK: send ServerKeyExchange if PSK identity hint if
                 * provided
                 */
#ifndef OPENSSL_NO_PSK
                /* Only send SKE if we have identity hint for plain PSK */
                || ((alg_k & (SSL_kPSK | SSL_kRSAPSK)) && s->ctx->psk_identity_hint)
                /* For other PSK always send SKE */
                || (alg_k & (SSL_PSK & (SSL_kDHEPSK | SSL_kECDHEPSK)))
#endif
#ifndef OPENSSL_NO_SRP
                /* SRP: send ServerKeyExchange */
                || (alg_k & SSL_kSRP)
#endif
                || (alg_k & SSL_kDHE)
                || (alg_k & SSL_kECDHE)
                || ((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)
                        )
                    )
                )
                ) {
                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)) ||
                   /* don't request certificate for SRP auth */
                   (s->s3->tmp.new_cipher->algorithm_auth & SSL_aSRP)
                   /*
                    * With normal PSK Certificates and Certificate Requests
                    * are omitted
                    */
                   || (s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)) {
                /* no cert request */
                skip = 1;
                s->s3->tmp.cert_request = 0;
                s->state = SSL3_ST_SW_SRVR_DONE_A;
                if (!ssl3_digest_cached_records(s, 0)) {
                    s->state = SSL_ST_ERR;
                    return -1;
                }
            } else {
                s->s3->tmp.cert_request = 1;
                ret = ssl3_send_certificate_request(s);
                if (ret <= 0)
                    goto end;
                s->state = SSL3_ST_SW_SRVR_DONE_A;
                s->init_num = 0;
            }
            break;

        case SSL3_ST_SW_SRVR_DONE_A:
        case SSL3_ST_SW_SRVR_DONE_B:
            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:

            /*
             * This code originally checked to see if any data was pending
             * using BIO_CTRL_INFO and then flushed. This caused problems as
             * documented in PR#1939. The proposed fix doesn't completely
             * resolve this issue as buggy implementations of
             * BIO_CTRL_PENDING still exist. So instead we just flush
             * unconditionally.
             */

            s->rwstate = SSL_WRITING;
            if (BIO_flush(s->wbio) <= 0) {
                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;
            if (ret == 2) {
                /*
                 * For the ECDH ciphersuites when the client sends its ECDH
                 * pub key in a certificate, the CertificateVerify message is
                 * not sent. Also for GOST ciphersuites when the client uses
                 * its key from the certificate for key exchange.
                 */
                s->state = SSL3_ST_SR_CHANGE_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;
                if (!s->s3->handshake_buffer) {
                    SSLerr(SSL_F_SSL3_ACCEPT, ERR_R_INTERNAL_ERROR);
                    s->state = SSL_ST_ERR;
                    return -1;
                }
                /*
                 * For sigalgs freeze the handshake buffer. If we support
                 * extms we've done this already so this is a no-op
                 */
                if (!ssl3_digest_cached_records(s, 1)) {
                    s->state = SSL_ST_ERR;
                    return -1;
                }
            } else {
                int offset = 0;
                int dgst_num;

                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 FIXME - digest processing for
                 * CertificateVerify should be generalized. But it is next
                 * step
                 */
                if (!ssl3_digest_cached_records(s, 0)) {
                    s->state = SSL_ST_ERR;
                    return -1;
                }
                for (dgst_num = 0; dgst_num < SSL_MAX_DIGEST; dgst_num++)
                    if (s->s3->handshake_dgst[dgst_num]) {
                        int dgst_size;

                        s->method->ssl3_enc->cert_verify_mac(s,
                                                             EVP_MD_CTX_type
                                                             (s->
                                                              s3->handshake_dgst
                                                              [dgst_num]),
                                                             &(s->s3->
                                                               tmp.cert_verify_md
                                                               [offset]));
                        dgst_size =
                            EVP_MD_CTX_size(s->s3->handshake_dgst[dgst_num]);
                        if (dgst_size < 0) {
                            s->state = SSL_ST_ERR;
                            ret = -1;
                            goto end;
                        }
                        offset += dgst_size;
                    }
            }
            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;

            s->state = SSL3_ST_SR_CHANGE_A;
            s->init_num = 0;
            break;

#if !defined(OPENSSL_NO_NEXTPROTONEG)
        case SSL3_ST_SR_NEXT_PROTO_A:
        case SSL3_ST_SR_NEXT_PROTO_B:
            ret = ssl3_get_next_proto(s);
            if (ret <= 0)
                goto end;
            s->init_num = 0;
            s->state = SSL3_ST_SR_FINISHED_A;
            break;
#endif


        case SSL3_ST_SR_CHANGE_A:
        case SSL3_ST_SR_CHANGE_B:
            ret = ssl3_get_change_cipher_spec(s, SSL3_ST_SR_CHANGE_A,
                                              SSL3_ST_SR_CHANGE_B);
            if (ret <= 0)
                goto end;

#if defined(OPENSSL_NO_NEXTPROTONEG)
            s->state = SSL3_ST_SR_FINISHED_A;
#else
            if (s->s3->next_proto_neg_seen)
                s->state = SSL3_ST_SR_NEXT_PROTO_A;
            else
                s->state = SSL3_ST_SR_FINISHED_A;
#endif
            s->init_num = 0;
            break;

        case SSL3_ST_SR_FINISHED_A:
        case SSL3_ST_SR_FINISHED_B:
            ret = ssl3_get_finished(s, SSL3_ST_SR_FINISHED_A,
                                    SSL3_ST_SR_FINISHED_B);
            if (ret <= 0)
                goto end;
            if (s->hit)
                s->state = SSL_ST_OK;
            else if (s->tlsext_ticket_expected)
                s->state = SSL3_ST_SW_SESSION_TICKET_A;
            else
                s->state = SSL3_ST_SW_CHANGE_A;
            s->init_num = 0;
            break;

        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;

        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 = ssl3_send_change_cipher_spec(s,
                                               SSL3_ST_SW_CHANGE_A,
                                               SSL3_ST_SW_CHANGE_B);

            if (ret <= 0)
                goto end;
            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;
            }

            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_CHANGE_A;
            } else
                s->s3->tmp.next_state = SSL_ST_OK;
            s->init_num = 0;
            break;

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

            BUF_MEM_free(s->init_buf);
            s->init_buf = NULL;

            /* 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 = ssl3_accept;

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

            ret = 1;
            goto end;
            /* break; */

        case SSL_ST_ERR:
        default:
            SSLerr(SSL_F_SSL3_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--;
    if (cb != NULL)
        cb(s, SSL_CB_ACCEPT_EXIT, ret);
    return (ret);
}

int ssl3_send_hello_request(SSL *s)
{

    if (s->state == SSL3_ST_SW_HELLO_REQ_A) {
        if (!ssl_set_handshake_header(s, SSL3_MT_HELLO_REQUEST, 0)) {
            SSLerr(SSL_F_SSL3_SEND_HELLO_REQUEST, ERR_R_INTERNAL_ERROR);
            return -1;
        }
        s->state = SSL3_ST_SW_HELLO_REQ_B;
    }

    /* SSL3_ST_SW_HELLO_REQ_B */
    return ssl_do_write(s);
}

int ssl3_get_client_hello(SSL *s)
{
    int i, ok, al = SSL_AD_INTERNAL_ERROR, ret = -1;
    unsigned int j, complen = 0;
    long n;
    unsigned long id;
    SSL_CIPHER *c;
#ifndef OPENSSL_NO_COMP
    SSL_COMP *comp = NULL;
#endif
    STACK_OF(SSL_CIPHER) *ciphers = NULL;
    int protverr = 1;
    PACKET pkt, cipher_suite, compression;

    if (s->state == SSL3_ST_SR_CLNT_HELLO_C && !s->first_packet)
        goto retry_cert;

    /*
     * We do this so that we will respond with our native type. If we are
     * TLSv1 and we get SSLv3, we will respond with TLSv1, This down
     * switching should be handled by a different method. If we are SSLv3, we
     * will respond with SSLv3, even if prompted with TLSv1.
     */
    if (s->state == SSL3_ST_SR_CLNT_HELLO_A) {
        s->state = SSL3_ST_SR_CLNT_HELLO_B;
    }
    s->first_packet = 1;
    n = s->method->ssl_get_message(s,
                                   SSL3_ST_SR_CLNT_HELLO_B,
                                   SSL3_ST_SR_CLNT_HELLO_C,
                                   SSL3_MT_CLIENT_HELLO,
                                   SSL3_RT_MAX_PLAIN_LENGTH, &ok);

    if (!ok)
        return ((int)n);
    s->first_packet = 0;
    if (!PACKET_buf_init(&pkt, s->init_msg, n)) {
        SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
        al = SSL_AD_INTERNAL_ERROR;
        goto f_err;
    }

    /* First lets get s->client_version set correctly */
    if (RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
        unsigned int version;
        unsigned int mt;
        /*-
         * An SSLv3/TLSv1 backwards-compatible CLIENT-HELLO in an SSLv2
         * header is sent directly on the wire, not wrapped as a TLS
         * record. Our record layer just processes the message length and passes
         * the rest right through. Its format is:
         * Byte  Content
         * 0-1   msg_length - decoded by the record layer
         * 2     msg_type - s->init_msg points here
         * 3-4   version
         * 5-6   cipher_spec_length
         * 7-8   session_id_length
         * 9-10  challenge_length
         * ...   ...
         */

        if (!PACKET_get_1(&pkt, &mt)
                || mt != SSL2_MT_CLIENT_HELLO) {
            /*
             * Should never happen. We should have tested this in the record
             * layer in order to have determined that this is a SSLv2 record
             * in the first place
             */
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
            goto err;
        }

        if (!PACKET_get_net_2(&pkt, &version)) {
            /* No protocol version supplied! */
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
            goto err;
        }
        if (version == 0x0002) {
            /* This is real SSLv2. We don't support it. */
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
            goto err;
        } else if ((version & 0xff00) == (SSL3_VERSION_MAJOR << 8)) {
            /* SSLv3/TLS */
            s->client_version = version;
        } else {
            /* No idea what protocol this is */
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
            goto err;
        }
    } else {
        /*
         * use version from inside client hello, not from record header (may
         * differ: see RFC 2246, Appendix E, second paragraph)
         */
        if(!PACKET_get_net_2(&pkt, (unsigned int *)&s->client_version)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_LENGTH_TOO_SHORT);
            goto f_err;
        }
    }

    /* Do SSL/TLS version negotiation if applicable */
    if (!SSL_IS_DTLS(s)) {
        if (s->version != TLS_ANY_VERSION) {
            if (s->client_version >= s->version) {
                protverr = 0;
            }
        } else if (s->client_version >= SSL3_VERSION) {
            switch(s->client_version) {
            default:
            case TLS1_2_VERSION:
                if(!(s->options & SSL_OP_NO_TLSv1_2)) {
                    s->version = TLS1_2_VERSION;
                    s->method = TLSv1_2_server_method();
                    protverr = 0;
                    break;
                }
                /* Deliberately fall through */
            case TLS1_1_VERSION:
                if(!(s->options & SSL_OP_NO_TLSv1_1)) {
                    s->version = TLS1_1_VERSION;
                    s->method = TLSv1_1_server_method();
                    protverr = 0;
                    break;
                }
                /* Deliberately fall through */
            case TLS1_VERSION:
                if(!(s->options & SSL_OP_NO_TLSv1)) {
                    s->version = TLS1_VERSION;
                    s->method = TLSv1_server_method();
                    protverr = 0;
                    break;
                }
                /* Deliberately fall through */
            case SSL3_VERSION:
#ifndef OPENSSL_NO_SSL3
                if(!(s->options & SSL_OP_NO_SSLv3)) {
                    s->version = SSL3_VERSION;
                    s->method = SSLv3_server_method();
                    protverr = 0;
                    break;
                }
#else
                break;
#endif
            }
        }
    } else if (s->client_version <= s->version
                || s->method->version == DTLS_ANY_VERSION) {
        /*
         * For DTLS we just check versions are potentially compatible. Version
         * negotiation comes later.
         */
        protverr = 0;
    }

    if (protverr) {
        SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_UNKNOWN_PROTOCOL);
        if ((!s->enc_write_ctx && !s->write_hash)) {
            /*
             * similar to ssl3_get_record, send alert using remote version
             * number
             */
            s->version = s->client_version;
        }
        al = SSL_AD_PROTOCOL_VERSION;
        goto f_err;
    }

    if (RECORD_LAYER_is_sslv2_record(&s->rlayer)) {
        /*
         * Handle an SSLv2 backwards compatible ClientHello
         * Note, this is only for SSLv3+ using the backward compatible format.
         * Real SSLv2 is not supported, and is rejected above.
         */
        unsigned int cipher_len, session_id_len, challenge_len;

        if (!PACKET_get_net_2(&pkt, &cipher_len)
                || !PACKET_get_net_2(&pkt, &session_id_len)
                || !PACKET_get_net_2(&pkt, &challenge_len)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_RECORD_LENGTH_MISMATCH);
            al = SSL_AD_DECODE_ERROR;
            goto f_err;
        }

        if (cipher_len == 0) {
            /* we need at least one cipher */
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_NO_CIPHERS_SPECIFIED);
            goto f_err;
        }

        if (!PACKET_get_sub_packet(&pkt, &cipher_suite, cipher_len)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_RECORD_LENGTH_MISMATCH);
            al = SSL_AD_DECODE_ERROR;
            goto f_err;
        }

        if (ssl_bytes_to_cipher_list(s, PACKET_data(&cipher_suite),
                                     cipher_len, &(ciphers), 1) == NULL) {
            goto err;
        }

        /*
         * Ignore any session id. We don't allow resumption in a backwards
         * compatible ClientHello
         */
        if (!PACKET_forward(&pkt, session_id_len)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_RECORD_LENGTH_MISMATCH);
            al = SSL_AD_DECODE_ERROR;
            goto f_err;
        }
        s->hit = 0;

        if (!ssl_get_new_session(s, 1))
            goto err;

        /* Load the client random */
        i = challenge_len > SSL3_RANDOM_SIZE ? SSL3_RANDOM_SIZE : challenge_len;
        memset(s->s3->client_random, 0, SSL3_RANDOM_SIZE);
        if (!PACKET_peek_copy_bytes(&pkt,
                                    s->s3->client_random + SSL3_RANDOM_SIZE - i,
                                    i)
                || !PACKET_forward(&pkt, challenge_len)
                || PACKET_remaining(&pkt) != 0) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_RECORD_LENGTH_MISMATCH);
            al = SSL_AD_DECODE_ERROR;
            goto f_err;
        }
    } else {
        /* If we get here we've got SSLv3+ in an SSLv3+ record */
        PACKET session_id;
        unsigned int cookie_len;
        /* load the client random and get the session-id */
        if (!PACKET_copy_bytes(&pkt, s->s3->client_random, SSL3_RANDOM_SIZE)
		|| !PACKET_get_length_prefixed_1(&pkt, &session_id)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_LENGTH_TOO_SHORT);
            goto f_err;
        }

        /*
         * If we require cookies and this ClientHello doesn't contain one, just
         * return since we do not want to allocate any memory yet. So check
         * cookie length...
         */
        if (SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE) {

            if (!PACKET_peek_1(&pkt, &cookie_len)) {
                al = SSL_AD_DECODE_ERROR;
                SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_LENGTH_TOO_SHORT);
                goto f_err;
            }

            if (cookie_len == 0)
                return 1;
        }

        s->hit = 0;
        /*
         * Versions before 0.9.7 always allow clients to resume sessions in
         * renegotiation. 0.9.7 and later allow this by default, but optionally
         * ignore resumption requests with flag
         * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION (it's a new flag rather
         * than a change to default behavior so that applications relying on
         * this for security won't even compile against older library versions).
         * 1.0.1 and later also have a function SSL_renegotiate_abbreviated() to
         * request renegotiation but not a new session (s->new_session remains
         * unset): for servers, this essentially just means that the
         * SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION setting will be
         * ignored.
         */
        if ((s->new_session
             && (s->options & SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION))) {
            if (!ssl_get_new_session(s, 1))
                goto err;
        } else {
            /*
             * TODO(openssl-team): ssl_get_prev_session passes a non-const
             * 'unsigned char*' session id to a user callback. Grab a copy of
             * the data?
             */
	    i = ssl_get_prev_session(s, &pkt, PACKET_data(&session_id),
		                     PACKET_remaining(&session_id));
            /*
             * Only resume if the session's version matches the negotiated
             * version.
             * RFC 5246 does not provide much useful advice on resumption
             * with a different protocol version. It doesn't forbid it but
             * the sanity of such behaviour would be questionable.
             * In practice, clients do not accept a version mismatch and
             * will abort the handshake with an error.
             */
            if (i == 1 && s->version == s->session->ssl_version) {
                /* previous session */
                s->hit = 1;
            } else if (i == -1)
                goto err;
            else {
                /* i == 0 */
                if (!ssl_get_new_session(s, 1))
                    goto err;
            }
        }

        if (SSL_IS_DTLS(s)) {
            PACKET cookie;
            if (!PACKET_get_length_prefixed_1(&pkt, &cookie)) {
                al = SSL_AD_DECODE_ERROR;
                SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_LENGTH_TOO_SHORT);
                goto f_err;
            }
	    cookie_len = PACKET_remaining(&cookie);
            /*
             * The ClientHello may contain a cookie even if the
             * HelloVerify message has not been sent--make sure that it
             * does not cause an overflow.
             */
            if (cookie_len > sizeof(s->d1->rcvd_cookie)) {
                /* too much data */
                al = SSL_AD_DECODE_ERROR;
                SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_COOKIE_MISMATCH);
                goto f_err;
            }

            /* verify the cookie if appropriate option is set. */
            if ((SSL_get_options(s) & SSL_OP_COOKIE_EXCHANGE)
                    && cookie_len > 0) {
                /* Get cookie */
                /*
                 * TODO(openssl-team): rcvd_cookie appears unused outside this
                 * function. Remove the field?
                 */
                if (!PACKET_copy_bytes(&cookie, s->d1->rcvd_cookie, cookie_len)) {
                    al = SSL_AD_INTERNAL_ERROR;
                    SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
                    goto f_err;
                }

                if (s->ctx->app_verify_cookie_cb != NULL) {
                    if (s->ctx->app_verify_cookie_cb(s, s->d1->rcvd_cookie,
                                                     cookie_len) == 0) {
                        al = SSL_AD_HANDSHAKE_FAILURE;
                        SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,
                               SSL_R_COOKIE_MISMATCH);
                        goto f_err;
                    }
                    /* else cookie verification succeeded */
                }
                /* default verification */
                else if (memcmp(s->d1->rcvd_cookie, s->d1->cookie,
                                s->d1->cookie_len) != 0) {
                    al = SSL_AD_HANDSHAKE_FAILURE;
                    SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_COOKIE_MISMATCH);
                    goto f_err;
                }
                /* Set to -2 so if successful we return 2 */
                ret = -2;
            }
            if (s->method->version == DTLS_ANY_VERSION) {
                /* Select version to use */
                if (s->client_version <= DTLS1_2_VERSION &&
                    !(s->options & SSL_OP_NO_DTLSv1_2)) {
                    s->version = DTLS1_2_VERSION;
                    s->method = DTLSv1_2_server_method();
                } else if (tls1_suiteb(s)) {
                    SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,
                           SSL_R_ONLY_DTLS_1_2_ALLOWED_IN_SUITEB_MODE);
                    s->version = s->client_version;
                    al = SSL_AD_PROTOCOL_VERSION;
                    goto f_err;
                } else if (s->client_version <= DTLS1_VERSION &&
                           !(s->options & SSL_OP_NO_DTLSv1)) {
                    s->version = DTLS1_VERSION;
                    s->method = DTLSv1_server_method();
                } else {
                    SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,
                           SSL_R_WRONG_VERSION_NUMBER);
                    s->version = s->client_version;
                    al = SSL_AD_PROTOCOL_VERSION;
                    goto f_err;
                }
                s->session->ssl_version = s->version;
            }
        }

        if (!PACKET_get_length_prefixed_2(&pkt, &cipher_suite)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_LENGTH_TOO_SHORT);
            goto f_err;
        }

        if (PACKET_remaining(&cipher_suite) == 0) {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_NO_CIPHERS_SPECIFIED);
            goto f_err;
        }

        if (ssl_bytes_to_cipher_list(s, PACKET_data(&cipher_suite),
                                     PACKET_remaining(&cipher_suite),
                                     &(ciphers), 0) == NULL) {
            goto err;
        }

        /* If it is a hit, check that the cipher is in the list */
        if (s->hit) {
            j = 0;
            id = s->session->cipher->id;

#ifdef CIPHER_DEBUG
            fprintf(stderr, "client sent %d ciphers\n",
                    sk_SSL_CIPHER_num(ciphers));
#endif
            for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
                c = sk_SSL_CIPHER_value(ciphers, i);
#ifdef CIPHER_DEBUG
                fprintf(stderr, "client [%2d of %2d]:%s\n",
                        i, sk_SSL_CIPHER_num(ciphers), SSL_CIPHER_get_name(c));
#endif
                if (c->id == id) {
                    j = 1;
                    break;
                }
            }
            /*
             * Disabled because it can be used in a ciphersuite downgrade
             * attack:
             * CVE-2010-4180.
             */
#if 0
            if (j == 0 && (s->options & SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG)
                && (sk_SSL_CIPHER_num(ciphers) == 1)) {
                /*
                 * Special case as client bug workaround: the previously used
                 * cipher may not be in the current list, the client instead
                 * might be trying to continue using a cipher that before wasn't
                 * chosen due to server preferences.  We'll have to reject the
                 * connection if the cipher is not enabled, though.
                 */
                c = sk_SSL_CIPHER_value(ciphers, 0);
                if (sk_SSL_CIPHER_find(SSL_get_ciphers(s), c) >= 0) {
                    s->session->cipher = c;
                    j = 1;
                }
            }
#endif
            if (j == 0) {
                /*
                 * we need to have the cipher in the cipher list if we are asked
                 * to reuse it
                 */
                al = SSL_AD_ILLEGAL_PARAMETER;
                SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,
                       SSL_R_REQUIRED_CIPHER_MISSING);
                goto f_err;
            }
        }

        /* compression */
        if (!PACKET_get_length_prefixed_1(&pkt, &compression)) {
            /* not enough data */
            al = SSL_AD_DECODE_ERROR;
            /*
             * TODO(openssl-team):
             * SSL_R_LENGTH_TOO_SHORT and SSL_R_LENGTH_MISMATCH are used
             * interchangeably. Pick one.
             */
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
            goto f_err;
        }

        complen = PACKET_remaining(&compression);
        for (j = 0; j < complen; j++) {
            if (PACKET_data(&compression)[j] == 0)
                break;
        }

        if (j >= complen) {
            /* no compress */
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_NO_COMPRESSION_SPECIFIED);
            goto f_err;
        }
    }

    /* TLS extensions */
    if (s->version >= SSL3_VERSION) {
        if (!ssl_parse_clienthello_tlsext(s, &pkt)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_PARSE_TLSEXT);
            goto err;
        }
    }

    /*
     * Check if we want to use external pre-shared secret for this handshake
     * for not reused session only. We need to generate server_random before
     * calling tls_session_secret_cb in order to allow SessionTicket
     * processing to use it in key derivation.
     */
    {
        unsigned char *pos;
        pos = s->s3->server_random;
        if (ssl_fill_hello_random(s, 1, pos, SSL3_RANDOM_SIZE) <= 0) {
            goto f_err;
        }
    }

    if (!s->hit && s->version >= TLS1_VERSION && s->tls_session_secret_cb) {
        SSL_CIPHER *pref_cipher = NULL;

        s->session->master_key_length = sizeof(s->session->master_key);
        if (s->tls_session_secret_cb(s, s->session->master_key,
                                     &s->session->master_key_length, ciphers,
                                     &pref_cipher,
                                     s->tls_session_secret_cb_arg)) {
            s->hit = 1;
            s->session->ciphers = ciphers;
            s->session->verify_result = X509_V_OK;

            ciphers = NULL;

            /* check if some cipher was preferred by call back */
            pref_cipher =
                pref_cipher ? pref_cipher : ssl3_choose_cipher(s,
                                                               s->
                                                               session->ciphers,
                                                               SSL_get_ciphers
                                                               (s));
            if (pref_cipher == NULL) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_NO_SHARED_CIPHER);
                goto f_err;
            }

            s->session->cipher = pref_cipher;
            sk_SSL_CIPHER_free(s->cipher_list);
            s->cipher_list = sk_SSL_CIPHER_dup(s->session->ciphers);
            sk_SSL_CIPHER_free(s->cipher_list_by_id);
            s->cipher_list_by_id = sk_SSL_CIPHER_dup(s->session->ciphers);
        }
    }

    /*
     * Worst case, we will use the NULL compression, but if we have other
     * options, we will now look for them.  We have complen-1 compression
     * algorithms from the client, starting at q.
     */
    s->s3->tmp.new_compression = NULL;
#ifndef OPENSSL_NO_COMP
    /* This only happens if we have a cache hit */
    if (s->session->compress_meth != 0) {
        int m, comp_id = s->session->compress_meth;
        unsigned int k;
        /* Perform sanity checks on resumed compression algorithm */
        /* Can't disable compression */
        if (!ssl_allow_compression(s)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,
                   SSL_R_INCONSISTENT_COMPRESSION);
            goto f_err;
        }
        /* Look for resumed compression method */
        for (m = 0; m < sk_SSL_COMP_num(s->ctx->comp_methods); m++) {
            comp = sk_SSL_COMP_value(s->ctx->comp_methods, m);
            if (comp_id == comp->id) {
                s->s3->tmp.new_compression = comp;
                break;
            }
        }
        if (s->s3->tmp.new_compression == NULL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,
                   SSL_R_INVALID_COMPRESSION_ALGORITHM);
            goto f_err;
        }
        /* Look for resumed method in compression list */
        for (k = 0; k < complen; k++) {
            if (PACKET_data(&compression)[k] == comp_id)
                break;
        }
        if (k >= complen) {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,
                   SSL_R_REQUIRED_COMPRESSSION_ALGORITHM_MISSING);
            goto f_err;
        }
    } else if (s->hit)
        comp = NULL;
    else if (ssl_allow_compression(s) && s->ctx->comp_methods) {
        /* See if we have a match */
        int m, nn, v, done = 0;
        unsigned int o;

        nn = sk_SSL_COMP_num(s->ctx->comp_methods);
        for (m = 0; m < nn; m++) {
            comp = sk_SSL_COMP_value(s->ctx->comp_methods, m);
            v = comp->id;
            for (o = 0; o < complen; o++) {
                if (v == PACKET_data(&compression)[o]) {
                    done = 1;
                    break;
                }
            }
            if (done)
                break;
        }
        if (done)
            s->s3->tmp.new_compression = comp;
        else
            comp = NULL;
    }
#else
    /*
     * If compression is disabled we'd better not try to resume a session
     * using compression.
     */
    if (s->session->compress_meth != 0) {
        SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_INCONSISTENT_COMPRESSION);
        goto f_err;
    }
#endif

    /*
     * Given s->session->ciphers and SSL_get_ciphers, we must pick a cipher
     */

    if (!s->hit) {
#ifdef OPENSSL_NO_COMP
        s->session->compress_meth = 0;
#else
        s->session->compress_meth = (comp == NULL) ? 0 : comp->id;
#endif
        sk_SSL_CIPHER_free(s->session->ciphers);
        s->session->ciphers = ciphers;
        if (ciphers == NULL) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
        ciphers = NULL;
        if (!tls1_set_server_sigalgs(s)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_CLIENTHELLO_TLSEXT);
            goto err;
        }
        /* Let cert callback update server certificates if required */
 retry_cert:
        if (s->cert->cert_cb) {
            int rv = s->cert->cert_cb(s, s->cert->cert_cb_arg);
            if (rv == 0) {
                al = SSL_AD_INTERNAL_ERROR;
                SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_CERT_CB_ERROR);
                goto f_err;
            }
            if (rv < 0) {
                s->rwstate = SSL_X509_LOOKUP;
                return -1;
            }
            s->rwstate = SSL_NOTHING;
        }
        c = ssl3_choose_cipher(s, s->session->ciphers, SSL_get_ciphers(s));

        if (c == NULL) {
            al = SSL_AD_HANDSHAKE_FAILURE;
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_NO_SHARED_CIPHER);
            goto f_err;
        }
        s->s3->tmp.new_cipher = c;
        /* check whether we should disable session resumption */
        if (s->not_resumable_session_cb != NULL)
            s->session->not_resumable = s->not_resumable_session_cb(s,
                                                                    ((c->algorithm_mkey & (SSL_kDHE | SSL_kECDHE))
                                                                     != 0));
        if (s->session->not_resumable)
            /* do not send a session ticket */
            s->tlsext_ticket_expected = 0;
    } else {
        /* Session-id reuse */
        s->s3->tmp.new_cipher = s->session->cipher;
    }

    if (!SSL_USE_SIGALGS(s) || !(s->verify_mode & SSL_VERIFY_PEER)) {
        if (!ssl3_digest_cached_records(s, 0))
            goto f_err;
    }

    /*-
     * we now have the following setup.
     * client_random
     * cipher_list          - our prefered list of ciphers
     * ciphers              - the clients prefered list of ciphers
     * compression          - basically ignored right now
     * ssl version is set   - sslv3
     * s->session           - The ssl session has been setup.
     * s->hit               - session reuse flag
     * s->s3->tmp.new_cipher- the new cipher to use.
     */

    /* Handles TLS extensions that we couldn't check earlier */
    if (s->version >= SSL3_VERSION) {
        if (ssl_check_clienthello_tlsext_late(s) <= 0) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_CLIENTHELLO_TLSEXT);
            goto err;
        }
    }

    if (ret < 0)
        ret = -ret;
    if (0) {
 f_err:
        ssl3_send_alert(s, SSL3_AL_FATAL, al);
 err:
        s->state = SSL_ST_ERR;
    }

    sk_SSL_CIPHER_free(ciphers);
    return ret < 0 ? -1 : ret;
}

int ssl3_send_server_hello(SSL *s)
{
    unsigned char *buf;
    unsigned char *p, *d;
    int i, sl;
    int al = 0;
    unsigned long l;

    if (s->state == SSL3_ST_SW_SRVR_HELLO_A) {
        buf = (unsigned char *)s->init_buf->data;

        /* Do the message type and length last */
        d = p = ssl_handshake_start(s);

        *(p++) = s->version >> 8;
        *(p++) = s->version & 0xff;

        /*
         * Random stuff. Filling of the server_random takes place in
         * ssl3_get_client_hello()
         */
        memcpy(p, s->s3->server_random, SSL3_RANDOM_SIZE);
        p += SSL3_RANDOM_SIZE;

        /*-
         * There are several cases for the session ID to send
         * back in the server hello:
         * - For session reuse from the session cache,
         *   we send back the old session ID.
         * - If stateless session reuse (using a session ticket)
         *   is successful, we send back the client's "session ID"
         *   (which doesn't actually identify the session).
         * - If it is a new session, we send back the new
         *   session ID.
         * - However, if we want the new session to be single-use,
         *   we send back a 0-length session ID.
         * s->hit is non-zero in either case of session reuse,
         * so the following won't overwrite an ID that we're supposed
         * to send back.
         */
        if (s->session->not_resumable ||
            (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER)
             && !s->hit))
            s->session->session_id_length = 0;

        sl = s->session->session_id_length;
        if (sl > (int)sizeof(s->session->session_id)) {
            SSLerr(SSL_F_SSL3_SEND_SERVER_HELLO, ERR_R_INTERNAL_ERROR);
            s->state = SSL_ST_ERR;
            return -1;
        }
        *(p++) = sl;
        memcpy(p, s->session->session_id, sl);
        p += sl;

        /* put the cipher */
        i = ssl3_put_cipher_by_char(s->s3->tmp.new_cipher, p);
        p += i;

        /* put the compression method */
#ifdef OPENSSL_NO_COMP
        *(p++) = 0;
#else
        if (s->s3->tmp.new_compression == NULL)
            *(p++) = 0;
        else
            *(p++) = s->s3->tmp.new_compression->id;
#endif

        if (ssl_prepare_serverhello_tlsext(s) <= 0) {
            SSLerr(SSL_F_SSL3_SEND_SERVER_HELLO, SSL_R_SERVERHELLO_TLSEXT);
            s->state = SSL_ST_ERR;
            return -1;
        }
        if ((p =
             ssl_add_serverhello_tlsext(s, p, buf + SSL3_RT_MAX_PLAIN_LENGTH,
                                        &al)) == NULL) {
            ssl3_send_alert(s, SSL3_AL_FATAL, al);
            SSLerr(SSL_F_SSL3_SEND_SERVER_HELLO, ERR_R_INTERNAL_ERROR);
            s->state = SSL_ST_ERR;
            return -1;
        }

        /* do the header */
        l = (p - d);
        if (!ssl_set_handshake_header(s, SSL3_MT_SERVER_HELLO, l)) {
            SSLerr(SSL_F_SSL3_SEND_SERVER_HELLO, ERR_R_INTERNAL_ERROR);
            return -1;
        }
        s->state = SSL3_ST_SW_SRVR_HELLO_B;
    }

    /* SSL3_ST_SW_SRVR_HELLO_B */
    return ssl_do_write(s);
}

int ssl3_send_server_done(SSL *s)
{

    if (s->state == SSL3_ST_SW_SRVR_DONE_A) {
        if (!ssl_set_handshake_header(s, SSL3_MT_SERVER_DONE, 0)) {
            SSLerr(SSL_F_SSL3_SEND_SERVER_DONE, ERR_R_INTERNAL_ERROR);
            return -1;
        }
        s->state = SSL3_ST_SW_SRVR_DONE_B;
    }

    /* SSL3_ST_SW_SRVR_DONE_B */
    return ssl_do_write(s);
}

int ssl3_send_server_key_exchange(SSL *s)
{
#ifndef OPENSSL_NO_RSA
    unsigned char *q;
    int j, num;
    RSA *rsa;
    unsigned char md_buf[MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH];
    unsigned int u;
#endif
#ifndef OPENSSL_NO_DH
    DH *dh = NULL, *dhp;
#endif
#ifndef OPENSSL_NO_EC
    EC_KEY *ecdh = NULL, *ecdhp;
    unsigned char *encodedPoint = NULL;
    int encodedlen = 0;
    int curve_id = 0;
    BN_CTX *bn_ctx = NULL;
#endif
    EVP_PKEY *pkey;
    const EVP_MD *md = NULL;
    unsigned char *p, *d;
    int al, i;
    unsigned long type;
    int n;
    CERT *cert;
    BIGNUM *r[4];
    int nr[4], kn;
    BUF_MEM *buf;
    EVP_MD_CTX md_ctx;

    EVP_MD_CTX_init(&md_ctx);
    if (s->state == SSL3_ST_SW_KEY_EXCH_A) {
        type = s->s3->tmp.new_cipher->algorithm_mkey;
        cert = s->cert;

        buf = s->init_buf;

        r[0] = r[1] = r[2] = r[3] = NULL;
        n = 0;
#ifndef OPENSSL_NO_PSK
        if (type & SSL_PSK) {
            /*
             * reserve size for record length and PSK identity hint
             */
            n += 2;
            if (s->ctx->psk_identity_hint)
                n += strlen(s->ctx->psk_identity_hint);
        }
        /* Plain PSK or RSAPSK nothing to do */
        if (type & (SSL_kPSK | SSL_kRSAPSK)) {
        } else
#endif                          /* !OPENSSL_NO_PSK */
#ifndef OPENSSL_NO_RSA
        if (type & SSL_kRSA) {
            rsa = cert->rsa_tmp;
            if ((rsa == NULL) && (s->cert->rsa_tmp_cb != NULL)) {
                rsa = s->cert->rsa_tmp_cb(s,
                                          SSL_C_IS_EXPORT(s->s3->
                                                          tmp.new_cipher),
                                          SSL_C_EXPORT_PKEYLENGTH(s->s3->
                                                                  tmp.new_cipher));
                if (rsa == NULL) {
                    al = SSL_AD_HANDSHAKE_FAILURE;
                    SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                           SSL_R_ERROR_GENERATING_TMP_RSA_KEY);
                    goto f_err;
                }
                RSA_up_ref(rsa);
                cert->rsa_tmp = rsa;
            }
            if (rsa == NULL) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_MISSING_TMP_RSA_KEY);
                goto f_err;
            }
            r[0] = rsa->n;
            r[1] = rsa->e;
            s->s3->tmp.use_rsa_tmp = 1;
        } else
#endif
#ifndef OPENSSL_NO_DH
        if (type & (SSL_kDHE | SSL_kDHEPSK)) {
            if (s->cert->dh_tmp_auto) {
                dhp = ssl_get_auto_dh(s);
                if (dhp == NULL) {
                    al = SSL_AD_INTERNAL_ERROR;
                    SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                           ERR_R_INTERNAL_ERROR);
                    goto f_err;
                }
            } else
                dhp = cert->dh_tmp;
            if ((dhp == NULL) && (s->cert->dh_tmp_cb != NULL))
                dhp = s->cert->dh_tmp_cb(s,
                                         SSL_C_IS_EXPORT(s->s3->
                                                         tmp.new_cipher),
                                         SSL_C_EXPORT_PKEYLENGTH(s->s3->
                                                                 tmp.new_cipher));
            if (dhp == NULL) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_MISSING_TMP_DH_KEY);
                goto f_err;
            }
            if (!ssl_security(s, SSL_SECOP_TMP_DH,
                              DH_security_bits(dhp), 0, dhp)) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_DH_KEY_TOO_SMALL);
                goto f_err;
            }
            if (s->s3->tmp.dh != NULL) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       ERR_R_INTERNAL_ERROR);
                goto err;
            }

            if (s->cert->dh_tmp_auto)
                dh = dhp;
            else if ((dh = DHparams_dup(dhp)) == NULL) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_DH_LIB);
                goto err;
            }

            s->s3->tmp.dh = dh;
            if ((dhp->pub_key == NULL ||
                 dhp->priv_key == NULL ||
                 (s->options & SSL_OP_SINGLE_DH_USE))) {
                if (!DH_generate_key(dh)) {
                    SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_DH_LIB);
                    goto err;
                }
            } else {
                dh->pub_key = BN_dup(dhp->pub_key);
                dh->priv_key = BN_dup(dhp->priv_key);
                if ((dh->pub_key == NULL) || (dh->priv_key == NULL)) {
                    SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_DH_LIB);
                    goto err;
                }
            }
            r[0] = dh->p;
            r[1] = dh->g;
            r[2] = dh->pub_key;
        } else
#endif
#ifndef OPENSSL_NO_EC
        if (type & (SSL_kECDHE | SSL_kECDHEPSK)) {
            const EC_GROUP *group;

            ecdhp = cert->ecdh_tmp;
            if (s->cert->ecdh_tmp_auto) {
                /* Get NID of appropriate shared curve */
                int nid = tls1_shared_curve(s, -2);
                if (nid != NID_undef)
                    ecdhp = EC_KEY_new_by_curve_name(nid);
            } else if ((ecdhp == NULL) && s->cert->ecdh_tmp_cb) {
                ecdhp = s->cert->ecdh_tmp_cb(s,
                                             SSL_C_IS_EXPORT(s->s3->
                                                             tmp.new_cipher),
                                             SSL_C_EXPORT_PKEYLENGTH(s->
                                                                     s3->tmp.new_cipher));
            }
            if (ecdhp == NULL) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_MISSING_TMP_ECDH_KEY);
                goto f_err;
            }

            if (s->s3->tmp.ecdh != NULL) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       ERR_R_INTERNAL_ERROR);
                goto err;
            }

            /* Duplicate the ECDH structure. */
            if (ecdhp == NULL) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_ECDH_LIB);
                goto err;
            }
            if (s->cert->ecdh_tmp_auto)
                ecdh = ecdhp;
            else if ((ecdh = EC_KEY_dup(ecdhp)) == NULL) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_ECDH_LIB);
                goto err;
            }

            s->s3->tmp.ecdh = ecdh;
            if ((EC_KEY_get0_public_key(ecdh) == NULL) ||
                (EC_KEY_get0_private_key(ecdh) == NULL) ||
                (s->options & SSL_OP_SINGLE_ECDH_USE)) {
                if (!EC_KEY_generate_key(ecdh)) {
                    SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                           ERR_R_ECDH_LIB);
                    goto err;
                }
            }

            if (((group = EC_KEY_get0_group(ecdh)) == NULL) ||
                (EC_KEY_get0_public_key(ecdh) == NULL) ||
                (EC_KEY_get0_private_key(ecdh) == NULL)) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_ECDH_LIB);
                goto err;
            }

            if (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher) &&
                (EC_GROUP_get_degree(group) > 163)) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_ECGROUP_TOO_LARGE_FOR_CIPHER);
                goto err;
            }

            /*
             * XXX: For now, we only support ephemeral ECDH keys over named
             * (not generic) curves. For supported named curves, curve_id is
             * non-zero.
             */
            if ((curve_id =
                 tls1_ec_nid2curve_id(EC_GROUP_get_curve_name(group)))
                == 0) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
                goto err;
            }

            /*
             * Encode the public key. First check the size of encoding and
             * allocate memory accordingly.
             */
            encodedlen = EC_POINT_point2oct(group,
                                            EC_KEY_get0_public_key(ecdh),
                                            POINT_CONVERSION_UNCOMPRESSED,
                                            NULL, 0, NULL);

            encodedPoint = (unsigned char *)
                OPENSSL_malloc(encodedlen * sizeof(unsigned char));
            bn_ctx = BN_CTX_new();
            if ((encodedPoint == NULL) || (bn_ctx == NULL)) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       ERR_R_MALLOC_FAILURE);
                goto err;
            }

            encodedlen = EC_POINT_point2oct(group,
                                            EC_KEY_get0_public_key(ecdh),
                                            POINT_CONVERSION_UNCOMPRESSED,
                                            encodedPoint, encodedlen, bn_ctx);

            if (encodedlen == 0) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_ECDH_LIB);
                goto err;
            }

            BN_CTX_free(bn_ctx);
            bn_ctx = NULL;

            /*
             * XXX: For now, we only support named (not generic) curves in
             * ECDH ephemeral key exchanges. In this situation, we need four
             * additional bytes to encode the entire ServerECDHParams
             * structure.
             */
            n += 4 + encodedlen;

            /*
             * We'll generate the serverKeyExchange message explicitly so we
             * can set these to NULLs
             */
            r[0] = NULL;
            r[1] = NULL;
            r[2] = NULL;
            r[3] = NULL;
        } else
#endif                          /* !OPENSSL_NO_EC */
#ifndef OPENSSL_NO_SRP
        if (type & SSL_kSRP) {
            if ((s->srp_ctx.N == NULL) ||
                (s->srp_ctx.g == NULL) ||
                (s->srp_ctx.s == NULL) || (s->srp_ctx.B == NULL)) {
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_MISSING_SRP_PARAM);
                goto err;
            }
            r[0] = s->srp_ctx.N;
            r[1] = s->srp_ctx.g;
            r[2] = s->srp_ctx.s;
            r[3] = s->srp_ctx.B;
        } else
#endif
        {
            al = SSL_AD_HANDSHAKE_FAILURE;
            SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                   SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE);
            goto f_err;
        }
        for (i = 0; i < 4 && r[i] != NULL; i++) {
            nr[i] = BN_num_bytes(r[i]);
#ifndef OPENSSL_NO_SRP
            if ((i == 2) && (type & SSL_kSRP))
                n += 1 + nr[i];
            else
#endif
                n += 2 + nr[i];
        }

        if (!(s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL|SSL_aSRP))
            && !(s->s3->tmp.new_cipher->algorithm_mkey & SSL_PSK)) {
            if ((pkey = ssl_get_sign_pkey(s, s->s3->tmp.new_cipher, &md))
                == NULL) {
                al = SSL_AD_DECODE_ERROR;
                goto f_err;
            }
            kn = EVP_PKEY_size(pkey);
        } else {
            pkey = NULL;
            kn = 0;
        }

        if (!BUF_MEM_grow_clean(buf, n + SSL_HM_HEADER_LENGTH(s) + kn)) {
            SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_LIB_BUF);
            goto err;
        }
        d = p = ssl_handshake_start(s);

#ifndef OPENSSL_NO_PSK
        if (type & SSL_PSK) {
            /* copy PSK identity hint */
            if (s->ctx->psk_identity_hint) {
                s2n(strlen(s->ctx->psk_identity_hint), p);
                strncpy((char *)p, s->ctx->psk_identity_hint,
                        strlen(s->ctx->psk_identity_hint));
                p += strlen(s->ctx->psk_identity_hint);
            } else {
                s2n(0, p);
            }
        }
#endif

        for (i = 0; i < 4 && r[i] != NULL; i++) {
#ifndef OPENSSL_NO_SRP
            if ((i == 2) && (type & SSL_kSRP)) {
                *p = nr[i];
                p++;
            } else
#endif
                s2n(nr[i], p);
            BN_bn2bin(r[i], p);
            p += nr[i];
        }

#ifndef OPENSSL_NO_EC
        if (type & (SSL_kECDHE | SSL_kECDHEPSK)) {
            /*
             * XXX: For now, we only support named (not generic) curves. In
             * this situation, the serverKeyExchange message has: [1 byte
             * CurveType], [2 byte CurveName] [1 byte length of encoded
             * point], followed by the actual encoded point itself
             */
            *p = NAMED_CURVE_TYPE;
            p += 1;
            *p = 0;
            p += 1;
            *p = curve_id;
            p += 1;
            *p = encodedlen;
            p += 1;
            memcpy(p, encodedPoint, encodedlen);
            OPENSSL_free(encodedPoint);
            encodedPoint = NULL;
            p += encodedlen;
        }
#endif

        /* not anonymous */
        if (pkey != NULL) {
            /*
             * n is the length of the params, they start at &(d[4]) and p
             * points to the space at the end.
             */
#ifndef OPENSSL_NO_RSA
            if (pkey->type == EVP_PKEY_RSA && !SSL_USE_SIGALGS(s)) {
                q = md_buf;
                j = 0;
                for (num = 2; num > 0; num--) {
                    EVP_MD_CTX_set_flags(&md_ctx,
                                         EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
                    EVP_DigestInit_ex(&md_ctx, (num == 2)
                                      ? s->ctx->md5 : s->ctx->sha1, NULL);
                    EVP_DigestUpdate(&md_ctx, &(s->s3->client_random[0]),
                                     SSL3_RANDOM_SIZE);
                    EVP_DigestUpdate(&md_ctx, &(s->s3->server_random[0]),
                                     SSL3_RANDOM_SIZE);
                    EVP_DigestUpdate(&md_ctx, d, n);
                    EVP_DigestFinal_ex(&md_ctx, q, (unsigned int *)&i);
                    q += i;
                    j += i;
                }
                if (RSA_sign(NID_md5_sha1, md_buf, j,
                             &(p[2]), &u, pkey->pkey.rsa) <= 0) {
                    SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_LIB_RSA);
                    goto err;
                }
                s2n(u, p);
                n += u + 2;
            } else
#endif
            if (md) {
                /* send signature algorithm */
                if (SSL_USE_SIGALGS(s)) {
                    if (!tls12_get_sigandhash(p, pkey, md)) {
                        /* Should never happen */
                        al = SSL_AD_INTERNAL_ERROR;
                        SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                               ERR_R_INTERNAL_ERROR);
                        goto f_err;
                    }
                    p += 2;
                }
#ifdef SSL_DEBUG
                fprintf(stderr, "Using hash %s\n", EVP_MD_name(md));
#endif
                EVP_SignInit_ex(&md_ctx, md, NULL);
                EVP_SignUpdate(&md_ctx, &(s->s3->client_random[0]),
                               SSL3_RANDOM_SIZE);
                EVP_SignUpdate(&md_ctx, &(s->s3->server_random[0]),
                               SSL3_RANDOM_SIZE);
                EVP_SignUpdate(&md_ctx, d, n);
                if (!EVP_SignFinal(&md_ctx, &(p[2]),
                                   (unsigned int *)&i, pkey)) {
                    SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_LIB_EVP);
                    goto err;
                }
                s2n(i, p);
                n += i + 2;
                if (SSL_USE_SIGALGS(s))
                    n += 2;
            } else {
                /* Is this error check actually needed? */
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
                       SSL_R_UNKNOWN_PKEY_TYPE);
                goto f_err;
            }
        }

        if (!ssl_set_handshake_header(s, SSL3_MT_SERVER_KEY_EXCHANGE, n)) {
            al = SSL_AD_HANDSHAKE_FAILURE;
            SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
    }

    s->state = SSL3_ST_SW_KEY_EXCH_B;
    EVP_MD_CTX_cleanup(&md_ctx);
    return ssl_do_write(s);
 f_err:
    ssl3_send_alert(s, SSL3_AL_FATAL, al);
 err:
#ifndef OPENSSL_NO_EC
    OPENSSL_free(encodedPoint);
    BN_CTX_free(bn_ctx);
#endif
    EVP_MD_CTX_cleanup(&md_ctx);
    s->state = SSL_ST_ERR;
    return (-1);
}

int ssl3_send_certificate_request(SSL *s)
{
    unsigned char *p, *d;
    int i, j, nl, off, n;
    STACK_OF(X509_NAME) *sk = NULL;
    X509_NAME *name;
    BUF_MEM *buf;

    if (s->state == SSL3_ST_SW_CERT_REQ_A) {
        buf = s->init_buf;

        d = p = ssl_handshake_start(s);

        /* get the list of acceptable cert types */
        p++;
        n = ssl3_get_req_cert_type(s, p);
        d[0] = n;
        p += n;
        n++;

        if (SSL_USE_SIGALGS(s)) {
            const unsigned char *psigs;
            unsigned char *etmp = p;
            nl = tls12_get_psigalgs(s, &psigs);
            /* Skip over length for now */
            p += 2;
            nl = tls12_copy_sigalgs(s, p, psigs, nl);
            /* Now fill in length */
            s2n(nl, etmp);
            p += nl;
            n += nl + 2;
        }

        off = n;
        p += 2;
        n += 2;

        sk = SSL_get_client_CA_list(s);
        nl = 0;
        if (sk != NULL) {
            for (i = 0; i < sk_X509_NAME_num(sk); i++) {
                name = sk_X509_NAME_value(sk, i);
                j = i2d_X509_NAME(name, NULL);
                if (!BUF_MEM_grow_clean
                    (buf, SSL_HM_HEADER_LENGTH(s) + n + j + 2)) {
                    SSLerr(SSL_F_SSL3_SEND_CERTIFICATE_REQUEST,
                           ERR_R_BUF_LIB);
                    goto err;
                }
                p = ssl_handshake_start(s) + n;
                s2n(j, p);
                i2d_X509_NAME(name, &p);
                n += 2 + j;
                nl += 2 + j;
            }
        }
        /* else no CA names */
        p = ssl_handshake_start(s) + off;
        s2n(nl, p);

        if (!ssl_set_handshake_header(s, SSL3_MT_CERTIFICATE_REQUEST, n)) {
            SSLerr(SSL_F_SSL3_SEND_CERTIFICATE_REQUEST, ERR_R_INTERNAL_ERROR);
            return -1;
        }

        s->state = SSL3_ST_SW_CERT_REQ_B;
    }

    /* SSL3_ST_SW_CERT_REQ_B */
    return ssl_do_write(s);
 err:
    s->state = SSL_ST_ERR;
    return (-1);
}

int ssl3_get_client_key_exchange(SSL *s)
{
    unsigned int i;
    int al, ok;
    long n;
    unsigned long alg_k;
#ifndef OPENSSL_NO_RSA
    RSA *rsa = NULL;
    EVP_PKEY *pkey = NULL;
#endif
#ifndef OPENSSL_NO_DH
    BIGNUM *pub = NULL;
    DH *dh_srvr, *dh_clnt = NULL;
#endif
#ifndef OPENSSL_NO_EC
    EC_KEY *srvr_ecdh = NULL;
    EVP_PKEY *clnt_pub_pkey = NULL;
    EC_POINT *clnt_ecpoint = NULL;
    BN_CTX *bn_ctx = NULL;
#endif
    PACKET pkt;
    unsigned char *data;
    size_t remain;

    n = s->method->ssl_get_message(s,
                                   SSL3_ST_SR_KEY_EXCH_A,
                                   SSL3_ST_SR_KEY_EXCH_B,
                                   SSL3_MT_CLIENT_KEY_EXCHANGE, 2048, &ok);

    if (!ok)
        return ((int)n);
    if (!PACKET_buf_init(&pkt, s->init_msg, n)) {
        al = SSL_AD_INTERNAL_ERROR;
        SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
        goto f_err;
    }

    alg_k = s->s3->tmp.new_cipher->algorithm_mkey;

#ifndef OPENSSL_NO_PSK
    /* For PSK parse and retrieve identity, obtain PSK key */
    if (alg_k & SSL_PSK) {
        unsigned char psk[PSK_MAX_PSK_LEN];
        size_t psklen;

        if (!PACKET_get_net_2(&pkt, &i)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
            goto f_err;
        }
        if (i > PSK_MAX_IDENTITY_LEN) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   SSL_R_DATA_LENGTH_TOO_LONG);
            goto f_err;
        }
        if (s->psk_server_callback == NULL) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   SSL_R_PSK_NO_SERVER_CB);
            goto f_err;
        }

        OPENSSL_free(s->session->psk_identity);
        s->session->psk_identity = OPENSSL_malloc(i + 1);
        if (s->session->psk_identity == NULL) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   ERR_R_MALLOC_FAILURE);
            goto f_err;
        }
        if (!PACKET_copy_bytes(&pkt, (unsigned char *)s->session->psk_identity,
                               i)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
            goto f_err;
        }
        s->session->psk_identity[i] = '\0';

        psklen = s->psk_server_callback(s, s->session->psk_identity,
                                         psk, sizeof(psk));

        if (psklen > PSK_MAX_PSK_LEN) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        } else if (psklen == 0) {
            /*
             * PSK related to the given identity not found
             */
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   SSL_R_PSK_IDENTITY_NOT_FOUND);
            al = SSL_AD_UNKNOWN_PSK_IDENTITY;
            goto f_err;
        }

        OPENSSL_free(s->s3->tmp.psk);
        s->s3->tmp.psk = BUF_memdup(psk, psklen);
        OPENSSL_cleanse(psk, psklen);

        if (s->s3->tmp.psk == NULL) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
            goto f_err;
        }

        s->s3->tmp.psklen = psklen;
    }
    if (alg_k & SSL_kPSK) {
        /* Identity extracted earlier: should be nothing left */
        if (PACKET_remaining(&pkt) != 0) {
            al = SSL_AD_HANDSHAKE_FAILURE;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
            goto f_err;
        }
        /* PSK handled by ssl_generate_master_secret */
        if (!ssl_generate_master_secret(s, NULL, 0, 0)) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
    } else
#endif
#ifndef OPENSSL_NO_RSA
    if (alg_k & (SSL_kRSA | SSL_kRSAPSK)) {
        unsigned char rand_premaster_secret[SSL_MAX_MASTER_KEY_LENGTH];
        int decrypt_len;
        unsigned char decrypt_good, version_good;
        size_t j;

        /* FIX THIS UP EAY EAY EAY EAY */
        if (s->s3->tmp.use_rsa_tmp) {
            if ((s->cert != NULL) && (s->cert->rsa_tmp != NULL))
                rsa = s->cert->rsa_tmp;
            /*
             * Don't do a callback because rsa_tmp should be sent already
             */
            if (rsa == NULL) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_MISSING_TMP_RSA_PKEY);
                goto f_err;

            }
        } else {
            pkey = s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey;
            if ((pkey == NULL) ||
                (pkey->type != EVP_PKEY_RSA) || (pkey->pkey.rsa == NULL)) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_MISSING_RSA_CERTIFICATE);
                goto f_err;
            }
            rsa = pkey->pkey.rsa;
        }

        /* TLS and [incidentally] DTLS{0xFEFF} */
        if (s->version > SSL3_VERSION && s->version != DTLS1_BAD_VER) {
            if (!PACKET_get_net_2(&pkt, &i)) {
                al = SSL_AD_DECODE_ERROR;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
                goto f_err;
            }
            remain = PACKET_remaining(&pkt);
            if (remain != i) {
                if (!(s->options & SSL_OP_TLS_D5_BUG)) {
                    al = SSL_AD_DECODE_ERROR;
                    SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                           SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG);
                    goto f_err;
                } else {
                    remain += 2;
                    if (!PACKET_back(&pkt, 2)) {
                        /*
                         * We already read these 2 bytes so this should never
                         * fail
                         */
                        al = SSL_AD_INTERNAL_ERROR;
                        SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                               ERR_R_INTERNAL_ERROR);
                        goto f_err;
                    }
                }
            }
        } else {
            remain = PACKET_remaining(&pkt);
        }

        /*
         * Reject overly short RSA ciphertext because we want to be sure
         * that the buffer size makes it safe to iterate over the entire
         * size of a premaster secret (SSL_MAX_MASTER_KEY_LENGTH). The
         * actual expected size is larger due to RSA padding, but the
         * bound is sufficient to be safe.
         */

        if (remain < SSL_MAX_MASTER_KEY_LENGTH) {
            al = SSL_AD_DECRYPT_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG);
            goto f_err;
        }

        if (!PACKET_get_bytes(&pkt, &data, remain)) {
            /* We already checked we had enough data so this shouldn't happen */
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
        /*
         * We must not leak whether a decryption failure occurs because of
         * Bleichenbacher's attack on PKCS #1 v1.5 RSA padding (see RFC 2246,
         * section 7.4.7.1). The code follows that advice of the TLS RFC and
         * generates a random premaster secret for the case that the decrypt
         * fails. See https://tools.ietf.org/html/rfc5246#section-7.4.7.1
         */

        if (RAND_bytes(rand_premaster_secret,
                              sizeof(rand_premaster_secret)) <= 0)
            goto err;
        decrypt_len =
            RSA_private_decrypt(remain, data, data, rsa, RSA_PKCS1_PADDING);
        ERR_clear_error();

        /*
         * decrypt_len should be SSL_MAX_MASTER_KEY_LENGTH. decrypt_good will
         * be 0xff if so and zero otherwise.
         */
        decrypt_good =
            constant_time_eq_int_8(decrypt_len, SSL_MAX_MASTER_KEY_LENGTH);

        /*
         * If the version in the decrypted pre-master secret is correct then
         * version_good will be 0xff, otherwise it'll be zero. The
         * Klima-Pokorny-Rosa extension of Bleichenbacher's attack
         * (http://eprint.iacr.org/2003/052/) exploits the version number
         * check as a "bad version oracle". Thus version checks are done in
         * constant time and are treated like any other decryption error.
         */
        version_good =
            constant_time_eq_8(data[0], (unsigned)(s->client_version >> 8));
        version_good &=
            constant_time_eq_8(data[1], (unsigned)(s->client_version & 0xff));

        /*
         * The premaster secret must contain the same version number as the
         * ClientHello to detect version rollback attacks (strangely, the
         * protocol does not offer such protection for DH ciphersuites).
         * However, buggy clients exist that send the negotiated protocol
         * version instead if the server does not support the requested
         * protocol version. If SSL_OP_TLS_ROLLBACK_BUG is set, tolerate such
         * clients.
         */
        if (s->options & SSL_OP_TLS_ROLLBACK_BUG) {
            unsigned char workaround_good;
            workaround_good =
                constant_time_eq_8(data[0], (unsigned)(s->version >> 8));
            workaround_good &=
                constant_time_eq_8(data[1], (unsigned)(s->version & 0xff));
            version_good |= workaround_good;
        }

        /*
         * Both decryption and version must be good for decrypt_good to
         * remain non-zero (0xff).
         */
        decrypt_good &= version_good;

        /*
         * Now copy rand_premaster_secret over from p using
         * decrypt_good_mask. If decryption failed, then p does not
         * contain valid plaintext, however, a check above guarantees
         * it is still sufficiently large to read from.
         */
        for (j = 0; j < sizeof(rand_premaster_secret); j++) {
            data[j] = constant_time_select_8(decrypt_good, data[j],
                                          rand_premaster_secret[j]);
        }

        if (!ssl_generate_master_secret(s, data, sizeof(rand_premaster_secret),
                                        0)) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
    } else
#endif
#ifndef OPENSSL_NO_DH
    if (alg_k & (SSL_kDHE | SSL_kDHr | SSL_kDHd | SSL_kDHEPSK)) {
        int idx = -1;
        EVP_PKEY *skey = NULL;
        size_t bookm;
        unsigned char shared[(OPENSSL_DH_MAX_MODULUS_BITS + 7) / 8];

        if (!PACKET_get_bookmark(&pkt, &bookm)) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
        if (!PACKET_get_net_2(&pkt, &i)) {
            if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_DH_PUBLIC_VALUE_LENGTH_IS_WRONG);
                goto f_err;
            }
            i = 0;
        }
        if (PACKET_remaining(&pkt) != i) {
            if (!(s->options & SSL_OP_SSLEAY_080_CLIENT_DH_BUG)) {
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_DH_PUBLIC_VALUE_LENGTH_IS_WRONG);
                goto err;
            } else {
                if (!PACKET_goto_bookmark(&pkt, bookm)) {
                    al = SSL_AD_INTERNAL_ERROR;
                    SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                           ERR_R_INTERNAL_ERROR);
                    goto f_err;
                }
                i = PACKET_remaining(&pkt);
            }
        }
        if (alg_k & SSL_kDHr)
            idx = SSL_PKEY_DH_RSA;
        else if (alg_k & SSL_kDHd)
            idx = SSL_PKEY_DH_DSA;
        if (idx >= 0) {
            skey = s->cert->pkeys[idx].privatekey;
            if ((skey == NULL) ||
                (skey->type != EVP_PKEY_DH) || (skey->pkey.dh == NULL)) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_MISSING_RSA_CERTIFICATE);
                goto f_err;
            }
            dh_srvr = skey->pkey.dh;
        } else if (s->s3->tmp.dh == NULL) {
            al = SSL_AD_HANDSHAKE_FAILURE;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   SSL_R_MISSING_TMP_DH_KEY);
            goto f_err;
        } else
            dh_srvr = s->s3->tmp.dh;

        if (n == 0L) {
            /* Get pubkey from cert */
            EVP_PKEY *clkey = X509_get_pubkey(s->session->peer);
            if (clkey) {
                if (EVP_PKEY_cmp_parameters(clkey, skey) == 1)
                    dh_clnt = EVP_PKEY_get1_DH(clkey);
            }
            if (dh_clnt == NULL) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_MISSING_TMP_DH_KEY);
                goto f_err;
            }
            EVP_PKEY_free(clkey);
            pub = dh_clnt->pub_key;
        } else {
            if (!PACKET_get_bytes(&pkt, &data, i)) {
                /* We already checked we have enough data */
                al = SSL_AD_INTERNAL_ERROR;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       ERR_R_INTERNAL_ERROR);
                goto f_err;
            }
            pub = BN_bin2bn(data, i, NULL);
        }
        if (pub == NULL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, SSL_R_BN_LIB);
            goto err;
        }

        i = DH_compute_key(shared, pub, dh_srvr);

        if (i <= 0) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_DH_LIB);
            BN_clear_free(pub);
            goto err;
        }

        DH_free(s->s3->tmp.dh);
        s->s3->tmp.dh = NULL;
        if (dh_clnt)
            DH_free(dh_clnt);
        else
            BN_clear_free(pub);
        pub = NULL;
        if (!ssl_generate_master_secret(s, shared, i, 0)) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
        if (dh_clnt)
            return 2;
    } else
#endif

#ifndef OPENSSL_NO_EC
    if (alg_k & (SSL_kECDHE | SSL_kECDHr | SSL_kECDHe | SSL_kECDHEPSK)) {
        int ret = 1;
        int field_size = 0;
        const EC_KEY *tkey;
        const EC_GROUP *group;
        const BIGNUM *priv_key;
        unsigned char *shared;

        /* initialize structures for server's ECDH key pair */
        if ((srvr_ecdh = EC_KEY_new()) == NULL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
            goto err;
        }

        /* Let's get server private key and group information */
        if (alg_k & (SSL_kECDHr | SSL_kECDHe)) {
            /* use the certificate */
            tkey = s->cert->pkeys[SSL_PKEY_ECC].privatekey->pkey.ec;
        } else {
            /*
             * use the ephermeral values we saved when generating the
             * ServerKeyExchange msg.
             */
            tkey = s->s3->tmp.ecdh;
        }

        group = EC_KEY_get0_group(tkey);
        priv_key = EC_KEY_get0_private_key(tkey);

        if (!EC_KEY_set_group(srvr_ecdh, group) ||
            !EC_KEY_set_private_key(srvr_ecdh, priv_key)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_EC_LIB);
            goto err;
        }

        /* Let's get client's public key */
        if ((clnt_ecpoint = EC_POINT_new(group)) == NULL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
            goto err;
        }

        if (n == 0L) {
            /* Client Publickey was in Client Certificate */

            if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_MISSING_TMP_ECDH_KEY);
                goto f_err;
            }
            if (((clnt_pub_pkey = X509_get_pubkey(s->session->peer))
                 == NULL) || (clnt_pub_pkey->type != EVP_PKEY_EC)) {
                /*
                 * XXX: For now, we do not support client authentication
                 * using ECDH certificates so this branch (n == 0L) of the
                 * code is never executed. When that support is added, we
                 * ought to ensure the key received in the certificate is
                 * authorized for key agreement. ECDH_compute_key implicitly
                 * checks that the two ECDH shares are for the same group.
                 */
                al = SSL_AD_HANDSHAKE_FAILURE;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_UNABLE_TO_DECODE_ECDH_CERTS);
                goto f_err;
            }

            if (EC_POINT_copy(clnt_ecpoint,
                              EC_KEY_get0_public_key(clnt_pub_pkey->
                                                     pkey.ec)) == 0) {
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_EC_LIB);
                goto err;
            }
            ret = 2;            /* Skip certificate verify processing */
        } else {
            /*
             * Get client's public key from encoded point in the
             * ClientKeyExchange message.
             */
            if ((bn_ctx = BN_CTX_new()) == NULL) {
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       ERR_R_MALLOC_FAILURE);
                goto err;
            }

            /* Get encoded point length */
            if (!PACKET_get_1(&pkt, &i)) {
                al = SSL_AD_DECODE_ERROR;
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                       SSL_R_LENGTH_MISMATCH);
                goto f_err;
            }
            if (!PACKET_get_bytes(&pkt, &data, i)
                    || PACKET_remaining(&pkt) != 0) {
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_EC_LIB);
                goto err;
            }
            if (EC_POINT_oct2point(group, clnt_ecpoint, data, i, bn_ctx) == 0) {
                SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_EC_LIB);
                goto err;
            }
        }

        /* Compute the shared pre-master secret */
        field_size = EC_GROUP_get_degree(group);
        if (field_size <= 0) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_ECDH_LIB);
            goto err;
        }
        shared = OPENSSL_malloc((field_size + 7) / 8);
        if (shared == NULL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
            goto err;
        }
        i = ECDH_compute_key(shared, (field_size + 7) / 8, clnt_ecpoint,
                             srvr_ecdh, NULL);
        if (i <= 0) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_ECDH_LIB);
            OPENSSL_free(shared);
            goto err;
        }

        EVP_PKEY_free(clnt_pub_pkey);
        EC_POINT_free(clnt_ecpoint);
        EC_KEY_free(srvr_ecdh);
        BN_CTX_free(bn_ctx);
        EC_KEY_free(s->s3->tmp.ecdh);
        s->s3->tmp.ecdh = NULL;

        if (!ssl_generate_master_secret(s, shared, i, 1)) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
        return (ret);
    } else
#endif
#ifndef OPENSSL_NO_SRP
    if (alg_k & SSL_kSRP) {
        if (!PACKET_get_net_2(&pkt, &i)
                || !PACKET_get_bytes(&pkt, &data, i)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, SSL_R_BAD_SRP_A_LENGTH);
            goto f_err;
        }
        if ((s->srp_ctx.A = BN_bin2bn(data, i, NULL)) == NULL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_BN_LIB);
            goto err;
        }
        if (BN_ucmp(s->srp_ctx.A, s->srp_ctx.N) >= 0
            || BN_is_zero(s->srp_ctx.A)) {
            al = SSL_AD_ILLEGAL_PARAMETER;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   SSL_R_BAD_SRP_PARAMETERS);
            goto f_err;
        }
        OPENSSL_free(s->session->srp_username);
        s->session->srp_username = BUF_strdup(s->srp_ctx.login);
        if (s->session->srp_username == NULL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
            goto err;
        }

        if (!srp_generate_server_master_secret(s)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto err;
        }
    } else
#endif                          /* OPENSSL_NO_SRP */
    if (alg_k & SSL_kGOST) {
        int ret = 0;
        EVP_PKEY_CTX *pkey_ctx;
        EVP_PKEY *client_pub_pkey = NULL, *pk = NULL;
        unsigned char premaster_secret[32], *start;
        size_t outlen = 32, inlen;
        unsigned long alg_a;
        int Ttag, Tclass;
        long Tlen;

        /* Get our certificate private key */
        alg_a = s->s3->tmp.new_cipher->algorithm_auth;
        if (alg_a & SSL_aGOST01)
            pk = s->cert->pkeys[SSL_PKEY_GOST01].privatekey;

        pkey_ctx = EVP_PKEY_CTX_new(pk, NULL);
        EVP_PKEY_decrypt_init(pkey_ctx);
        /*
         * If client certificate is present and is of the same type, maybe
         * use it for key exchange.  Don't mind errors from
         * EVP_PKEY_derive_set_peer, because it is completely valid to use a
         * client certificate for authorization only.
         */
        client_pub_pkey = X509_get_pubkey(s->session->peer);
        if (client_pub_pkey) {
            if (EVP_PKEY_derive_set_peer(pkey_ctx, client_pub_pkey) <= 0)
                ERR_clear_error();
        }
        /* Decrypt session key */
        if (!PACKET_get_bytes(&pkt, &data, n)) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
        if (ASN1_get_object
            ((const unsigned char **)&data, &Tlen, &Ttag, &Tclass,
             n) != V_ASN1_CONSTRUCTED || Ttag != V_ASN1_SEQUENCE
            || Tclass != V_ASN1_UNIVERSAL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   SSL_R_DECRYPTION_FAILED);
            goto gerr;
        }
        start = data;
        inlen = Tlen;
        if (EVP_PKEY_decrypt
            (pkey_ctx, premaster_secret, &outlen, start, inlen) <= 0) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                   SSL_R_DECRYPTION_FAILED);
            goto gerr;
        }
        /* Generate master secret */
        if (!ssl_generate_master_secret(s, premaster_secret,
                                        sizeof(premaster_secret), 0)) {
            al = SSL_AD_INTERNAL_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
            goto f_err;
        }
        /* Check if pubkey from client certificate was used */
        if (EVP_PKEY_CTX_ctrl
            (pkey_ctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 2, NULL) > 0)
            ret = 2;
        else
            ret = 1;
 gerr:
        EVP_PKEY_free(client_pub_pkey);
        EVP_PKEY_CTX_free(pkey_ctx);
        if (ret)
            return ret;
        goto err;
    } else {
        al = SSL_AD_HANDSHAKE_FAILURE;
        SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE, SSL_R_UNKNOWN_CIPHER_TYPE);
        goto f_err;
    }

    return (1);
 f_err:
    ssl3_send_alert(s, SSL3_AL_FATAL, al);
#if !defined(OPENSSL_NO_DH) || !defined(OPENSSL_NO_RSA) || !defined(OPENSSL_NO_EC) || defined(OPENSSL_NO_SRP)
 err:
#endif
#ifndef OPENSSL_NO_EC
    EVP_PKEY_free(clnt_pub_pkey);
    EC_POINT_free(clnt_ecpoint);
    EC_KEY_free(srvr_ecdh);
    BN_CTX_free(bn_ctx);
#endif
#ifndef OPENSSL_NO_PSK
    OPENSSL_clear_free(s->s3->tmp.psk, s->s3->tmp.psklen);
    s->s3->tmp.psk = NULL;
#endif
    s->state = SSL_ST_ERR;
    return (-1);
}

int ssl3_get_cert_verify(SSL *s)
{
    EVP_PKEY *pkey = NULL;
    unsigned char *sig, *data;
    int al, ok, ret = 0;
    long n;
    int type = 0, i, j;
    unsigned int len;
    X509 *peer;
    const EVP_MD *md = NULL;
    EVP_MD_CTX mctx;
    PACKET pkt;
    EVP_MD_CTX_init(&mctx);

    /*
     * We should only process a CertificateVerify message if we have received
     * a Certificate from the client. If so then |s->session->peer| will be non
     * NULL. In some instances a CertificateVerify message is not required even
     * if the peer has sent a Certificate (e.g. such as in the case of static
     * DH). In that case the ClientKeyExchange processing will skip the
     * CertificateVerify state so we should not arrive here.
     */
    if (s->session->peer == NULL) {
        ret = 1;
        goto end;
    }

    n = s->method->ssl_get_message(s,
                                   SSL3_ST_SR_CERT_VRFY_A,
                                   SSL3_ST_SR_CERT_VRFY_B,
                                   SSL3_MT_CERTIFICATE_VERIFY,
                                   SSL3_RT_MAX_PLAIN_LENGTH, &ok);

    if (!ok)
        return ((int)n);

    peer = s->session->peer;
    pkey = X509_get_pubkey(peer);
    type = X509_certificate_type(peer, pkey);

    if (!(type & EVP_PKT_SIGN)) {
        SSLerr(SSL_F_SSL3_GET_CERT_VERIFY,
               SSL_R_SIGNATURE_FOR_NON_SIGNING_CERTIFICATE);
        al = SSL_AD_ILLEGAL_PARAMETER;
        goto f_err;
    }

    /* we now have a signature that we need to verify */
    if (!PACKET_buf_init(&pkt, s->init_msg, n)) {
        SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
        al = SSL_AD_INTERNAL_ERROR;
        goto f_err;
    }
    /* Check for broken implementations of GOST ciphersuites */
    /*
     * If key is GOST and n is exactly 64, it is bare signature without
     * length field
     */
    if (n == 64 && pkey->type == NID_id_GostR3410_2001) {
        len = 64;
    } else {
        if (SSL_USE_SIGALGS(s)) {
            int rv;

            if (!PACKET_get_bytes(&pkt, &sig, 2)) {
                al = SSL_AD_DECODE_ERROR;
                goto f_err;
            }
            rv = tls12_check_peer_sigalg(&md, s, sig, pkey);
            if (rv == -1) {
                al = SSL_AD_INTERNAL_ERROR;
                goto f_err;
            } else if (rv == 0) {
                al = SSL_AD_DECODE_ERROR;
                goto f_err;
            }
#ifdef SSL_DEBUG
            fprintf(stderr, "USING TLSv1.2 HASH %s\n", EVP_MD_name(md));
#endif
        }
        if (!PACKET_get_net_2(&pkt, &len)) {
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_LENGTH_MISMATCH);
            al = SSL_AD_DECODE_ERROR;
            goto f_err;
        }
    }
    j = EVP_PKEY_size(pkey);
    if (((int)len > j) || ((int)PACKET_remaining(&pkt) > j) || (n <= 0)) {
        SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_WRONG_SIGNATURE_SIZE);
        al = SSL_AD_DECODE_ERROR;
        goto f_err;
    }
    if (!PACKET_get_bytes(&pkt, &data, len)) {
        SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_LENGTH_MISMATCH);
        al = SSL_AD_DECODE_ERROR;
        goto f_err;
    }

    if (SSL_USE_SIGALGS(s)) {
        long hdatalen = 0;
        void *hdata;
        hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
        if (hdatalen <= 0) {
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
            al = SSL_AD_INTERNAL_ERROR;
            goto f_err;
        }
#ifdef SSL_DEBUG
        fprintf(stderr, "Using TLS 1.2 with client verify alg %s\n",
                EVP_MD_name(md));
#endif
        if (!EVP_VerifyInit_ex(&mctx, md, NULL)
            || !EVP_VerifyUpdate(&mctx, hdata, hdatalen)) {
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, ERR_R_EVP_LIB);
            al = SSL_AD_INTERNAL_ERROR;
            goto f_err;
        }

        if (EVP_VerifyFinal(&mctx, data, len, pkey) <= 0) {
            al = SSL_AD_DECRYPT_ERROR;
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_BAD_SIGNATURE);
            goto f_err;
        }
    } else
#ifndef OPENSSL_NO_RSA
    if (pkey->type == EVP_PKEY_RSA) {
        i = RSA_verify(NID_md5_sha1, s->s3->tmp.cert_verify_md,
                       MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH, data, len,
                       pkey->pkey.rsa);
        if (i < 0) {
            al = SSL_AD_DECRYPT_ERROR;
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_BAD_RSA_DECRYPT);
            goto f_err;
        }
        if (i == 0) {
            al = SSL_AD_DECRYPT_ERROR;
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_BAD_RSA_SIGNATURE);
            goto f_err;
        }
    } else
#endif
#ifndef OPENSSL_NO_DSA
    if (pkey->type == EVP_PKEY_DSA) {
        j = DSA_verify(pkey->save_type,
                       &(s->s3->tmp.cert_verify_md[MD5_DIGEST_LENGTH]),
                       SHA_DIGEST_LENGTH, data, len, pkey->pkey.dsa);
        if (j <= 0) {
            /* bad signature */
            al = SSL_AD_DECRYPT_ERROR;
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_BAD_DSA_SIGNATURE);
            goto f_err;
        }
    } else
#endif
#ifndef OPENSSL_NO_EC
    if (pkey->type == EVP_PKEY_EC) {
        j = ECDSA_verify(pkey->save_type,
                         &(s->s3->tmp.cert_verify_md[MD5_DIGEST_LENGTH]),
                         SHA_DIGEST_LENGTH, data, len, pkey->pkey.ec);
        if (j <= 0) {
            /* bad signature */
            al = SSL_AD_DECRYPT_ERROR;
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_BAD_ECDSA_SIGNATURE);
            goto f_err;
        }
    } else
#endif
    if (pkey->type == NID_id_GostR3410_2001) {
        unsigned char signature[64];
        int idx;
        EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new(pkey, NULL);
        EVP_PKEY_verify_init(pctx);
        if (len != 64) {
            fprintf(stderr, "GOST signature length is %d", len);
        }
        for (idx = 0; idx < 64; idx++) {
            signature[63 - idx] = data[idx];
        }
        j = EVP_PKEY_verify(pctx, signature, 64, s->s3->tmp.cert_verify_md,
                            32);
        EVP_PKEY_CTX_free(pctx);
        if (j <= 0) {
            al = SSL_AD_DECRYPT_ERROR;
            SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, SSL_R_BAD_ECDSA_SIGNATURE);
            goto f_err;
        }
    } else {
        SSLerr(SSL_F_SSL3_GET_CERT_VERIFY, ERR_R_INTERNAL_ERROR);
        al = SSL_AD_UNSUPPORTED_CERTIFICATE;
        goto f_err;
    }

    ret = 1;
    if (0) {
 f_err:
        ssl3_send_alert(s, SSL3_AL_FATAL, al);
        s->state = SSL_ST_ERR;
    }
 end:
    BIO_free(s->s3->handshake_buffer);
    s->s3->handshake_buffer = NULL;
    EVP_MD_CTX_cleanup(&mctx);
    EVP_PKEY_free(pkey);
    return (ret);
}

int ssl3_get_client_certificate(SSL *s)
{
    int i, ok, al, ret = -1;
    X509 *x = NULL;
    unsigned long l, llen, n;
    const unsigned char *certstart;
    unsigned char *certbytes;
    STACK_OF(X509) *sk = NULL;
    PACKET pkt, spkt;

    n = s->method->ssl_get_message(s,
                                   SSL3_ST_SR_CERT_A,
                                   SSL3_ST_SR_CERT_B,
                                   -1, s->max_cert_list, &ok);

    if (!ok)
        return ((int)n);

    if (s->s3->tmp.message_type == SSL3_MT_CLIENT_KEY_EXCHANGE) {
        if ((s->verify_mode & SSL_VERIFY_PEER) &&
            (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
                   SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
            al = SSL_AD_HANDSHAKE_FAILURE;
            goto f_err;
        }
        /*
         * If tls asked for a client cert, the client must return a 0 list
         */
        if ((s->version > SSL3_VERSION) && s->s3->tmp.cert_request) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
                   SSL_R_TLS_PEER_DID_NOT_RESPOND_WITH_CERTIFICATE_LIST);
            al = SSL_AD_UNEXPECTED_MESSAGE;
            goto f_err;
        }
        s->s3->tmp.reuse_message = 1;
        return (1);
    }

    if (s->s3->tmp.message_type != SSL3_MT_CERTIFICATE) {
        al = SSL_AD_UNEXPECTED_MESSAGE;
        SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, SSL_R_WRONG_MESSAGE_TYPE);
        goto f_err;
    }

    if (!PACKET_buf_init(&pkt, s->init_msg, n)) {
        al = SSL_AD_INTERNAL_ERROR;
        SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, ERR_R_INTERNAL_ERROR);
        goto f_err;
    }

    if ((sk = sk_X509_new_null()) == NULL) {
        SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    if (!PACKET_get_net_3(&pkt, &llen)
            || !PACKET_get_sub_packet(&pkt, &spkt, llen)
            || PACKET_remaining(&pkt) != 0) {
        al = SSL_AD_DECODE_ERROR;
        SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, SSL_R_LENGTH_MISMATCH);
        goto f_err;
    }

    while (PACKET_remaining(&spkt) > 0) {
        if (!PACKET_get_net_3(&spkt, &l)
                || !PACKET_get_bytes(&spkt, &certbytes, l)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
                   SSL_R_CERT_LENGTH_MISMATCH);
            goto f_err;
        }

        certstart = certbytes;
        x = d2i_X509(NULL, (const unsigned char **)&certbytes, l);
        if (x == NULL) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, ERR_R_ASN1_LIB);
            goto done;
        }
        if (certbytes != (certstart + l)) {
            al = SSL_AD_DECODE_ERROR;
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
                   SSL_R_CERT_LENGTH_MISMATCH);
            goto f_err;
        }
        if (!sk_X509_push(sk, x)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, ERR_R_MALLOC_FAILURE);
            goto done;
        }
        x = NULL;
    }

    if (sk_X509_num(sk) <= 0) {
        /* TLS does not mind 0 certs returned */
        if (s->version == SSL3_VERSION) {
            al = SSL_AD_HANDSHAKE_FAILURE;
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
                   SSL_R_NO_CERTIFICATES_RETURNED);
            goto f_err;
        }
        /* Fail for TLS only if we required a certificate */
        else if ((s->verify_mode & SSL_VERIFY_PEER) &&
                 (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
                   SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
            al = SSL_AD_HANDSHAKE_FAILURE;
            goto f_err;
        }
        /* No client certificate so digest cached records */
        if (s->s3->handshake_buffer && !ssl3_digest_cached_records(s, 0)) {
            al = SSL_AD_INTERNAL_ERROR;
            goto f_err;
        }
    } else {
        EVP_PKEY *pkey;
        i = ssl_verify_cert_chain(s, sk);
        if (i <= 0) {
            al = ssl_verify_alarm_type(s->verify_result);
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
                   SSL_R_CERTIFICATE_VERIFY_FAILED);
            goto f_err;
        }
        if (i > 1) {
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, i);
            al = SSL_AD_HANDSHAKE_FAILURE;
            goto f_err;
        }
        pkey = X509_get_pubkey(sk_X509_value(sk, 0));
        if (pkey == NULL) {
            al = SSL3_AD_HANDSHAKE_FAILURE;
            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
                   SSL_R_UNKNOWN_CERTIFICATE_TYPE);
            goto f_err;
        }
        EVP_PKEY_free(pkey);
    }

    X509_free(s->session->peer);
    s->session->peer = sk_X509_shift(sk);
    s->session->verify_result = s->verify_result;

    sk_X509_pop_free(s->session->peer_chain, X509_free);
    s->session->peer_chain = sk;
    /*
     * Inconsistency alert: cert_chain does *not* include the peer's own
     * certificate, while we do include it in s3_clnt.c
     */
    sk = NULL;
    ret = 1;
    goto done;

 f_err:
    ssl3_send_alert(s, SSL3_AL_FATAL, al);
 done:
    s->state = SSL_ST_ERR;
    X509_free(x);
    sk_X509_pop_free(sk, X509_free);
    return (ret);
}

int ssl3_send_server_certificate(SSL *s)
{
    CERT_PKEY *cpk;

    if (s->state == SSL3_ST_SW_CERT_A) {
        cpk = ssl_get_server_send_pkey(s);
        if (cpk == NULL) {
            SSLerr(SSL_F_SSL3_SEND_SERVER_CERTIFICATE, ERR_R_INTERNAL_ERROR);
            s->state = SSL_ST_ERR;
            return (0);
        }

        if (!ssl3_output_cert_chain(s, cpk)) {
            SSLerr(SSL_F_SSL3_SEND_SERVER_CERTIFICATE, ERR_R_INTERNAL_ERROR);
            s->state = SSL_ST_ERR;
            return (0);
        }
        s->state = SSL3_ST_SW_CERT_B;
    }

    /* SSL3_ST_SW_CERT_B */
    return ssl_do_write(s);
}

/* send a new session ticket (not necessarily for a new session) */
int ssl3_send_newsession_ticket(SSL *s)
{
    unsigned char *senc = NULL;
    EVP_CIPHER_CTX ctx;
    HMAC_CTX hctx;

    if (s->state == SSL3_ST_SW_SESSION_TICKET_A) {
        unsigned char *p, *macstart;
        const unsigned char *const_p;
        int len, slen_full, slen;
        SSL_SESSION *sess;
        unsigned int hlen;
        SSL_CTX *tctx = s->initial_ctx;
        unsigned char iv[EVP_MAX_IV_LENGTH];
        unsigned char key_name[16];

        /* get session encoding length */
        slen_full = i2d_SSL_SESSION(s->session, NULL);
        /*
         * Some length values are 16 bits, so forget it if session is too
         * long
         */
        if (slen_full == 0 || slen_full > 0xFF00) {
            s->state = SSL_ST_ERR;
            return -1;
        }
        senc = OPENSSL_malloc(slen_full);
        if (!senc) {
            s->state = SSL_ST_ERR;
            return -1;
        }

        EVP_CIPHER_CTX_init(&ctx);
        HMAC_CTX_init(&hctx);

        p = senc;
        if (!i2d_SSL_SESSION(s->session, &p))
            goto err;

        /*
         * create a fresh copy (not shared with other threads) to clean up
         */
        const_p = senc;
        sess = d2i_SSL_SESSION(NULL, &const_p, slen_full);
        if (sess == NULL)
            goto err;
        sess->session_id_length = 0; /* ID is irrelevant for the ticket */

        slen = i2d_SSL_SESSION(sess, NULL);
        if (slen == 0 || slen > slen_full) { /* shouldn't ever happen */
            SSL_SESSION_free(sess);
            goto err;
        }
        p = senc;
        if (!i2d_SSL_SESSION(sess, &p)) {
            SSL_SESSION_free(sess);
            goto err;
        }
        SSL_SESSION_free(sess);

        /*-
         * Grow buffer if need be: the length calculation is as
         * follows handshake_header_length +
         * 4 (ticket lifetime hint) + 2 (ticket length) +
         * 16 (key name) + max_iv_len (iv length) +
         * session_length + max_enc_block_size (max encrypted session
         * length) + max_md_size (HMAC).
         */
        if (!BUF_MEM_grow(s->init_buf,
                          SSL_HM_HEADER_LENGTH(s) + 22 + EVP_MAX_IV_LENGTH +
                          EVP_MAX_BLOCK_LENGTH + EVP_MAX_MD_SIZE + slen))
            goto err;

        p = ssl_handshake_start(s);
        /*
         * Initialize HMAC and cipher contexts. If callback present it does
         * all the work otherwise use generated values from parent ctx.
         */
        if (tctx->tlsext_ticket_key_cb) {
            if (tctx->tlsext_ticket_key_cb(s, key_name, iv, &ctx,
                                           &hctx, 1) < 0)
                goto err;
        } else {
            if (RAND_bytes(iv, 16) <= 0)
                goto err;
            if (!EVP_EncryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL,
                                    tctx->tlsext_tick_aes_key, iv))
                goto err;
            if (!HMAC_Init_ex(&hctx, tctx->tlsext_tick_hmac_key, 16,
                              EVP_sha256(), NULL))
                goto err;
            memcpy(key_name, tctx->tlsext_tick_key_name, 16);
        }

        /*
         * Ticket lifetime hint (advisory only): We leave this unspecified
         * for resumed session (for simplicity), and guess that tickets for
         * new sessions will live as long as their sessions.
         */
        l2n(s->hit ? 0 : s->session->timeout, p);

        /* Skip ticket length for now */
        p += 2;
        /* Output key name */
        macstart = p;
        memcpy(p, key_name, 16);
        p += 16;
        /* output IV */
        memcpy(p, iv, EVP_CIPHER_CTX_iv_length(&ctx));
        p += EVP_CIPHER_CTX_iv_length(&ctx);
        /* Encrypt session data */
        if (!EVP_EncryptUpdate(&ctx, p, &len, senc, slen))
            goto err;
        p += len;
        if (!EVP_EncryptFinal(&ctx, p, &len))
            goto err;
        p += len;

        if (!HMAC_Update(&hctx, macstart, p - macstart))
            goto err;
        if (!HMAC_Final(&hctx, p, &hlen))
            goto err;

        EVP_CIPHER_CTX_cleanup(&ctx);
        HMAC_CTX_cleanup(&hctx);

        p += hlen;
        /* Now write out lengths: p points to end of data written */
        /* Total length */
        len = p - ssl_handshake_start(s);
        /* Skip ticket lifetime hint */
        p = ssl_handshake_start(s) + 4;
        s2n(len - 6, p);
        if (!ssl_set_handshake_header(s, SSL3_MT_NEWSESSION_TICKET, len))
            goto err;
        s->state = SSL3_ST_SW_SESSION_TICKET_B;
        OPENSSL_free(senc);
    }

    /* SSL3_ST_SW_SESSION_TICKET_B */
    return ssl_do_write(s);
 err:
    OPENSSL_free(senc);
    EVP_CIPHER_CTX_cleanup(&ctx);
    HMAC_CTX_cleanup(&hctx);
    s->state = SSL_ST_ERR;
    return -1;
}

int ssl3_send_cert_status(SSL *s)
{
    if (s->state == SSL3_ST_SW_CERT_STATUS_A) {
        unsigned char *p;
        /*-
         * Grow buffer if need be: the length calculation is as
         * follows 1 (message type) + 3 (message length) +
         * 1 (ocsp response type) + 3 (ocsp response length)
         * + (ocsp response)
         */
        if (!BUF_MEM_grow(s->init_buf, 8 + s->tlsext_ocsp_resplen)) {
            s->state = SSL_ST_ERR;
            return -1;
        }

        p = (unsigned char *)s->init_buf->data;

        /* do the header */
        *(p++) = SSL3_MT_CERTIFICATE_STATUS;
        /* message length */
        l2n3(s->tlsext_ocsp_resplen + 4, p);
        /* status type */
        *(p++) = s->tlsext_status_type;
        /* length of OCSP response */
        l2n3(s->tlsext_ocsp_resplen, p);
        /* actual response */
        memcpy(p, s->tlsext_ocsp_resp, s->tlsext_ocsp_resplen);
        /* number of bytes to write */
        s->init_num = 8 + s->tlsext_ocsp_resplen;
        s->state = SSL3_ST_SW_CERT_STATUS_B;
        s->init_off = 0;
    }

    /* SSL3_ST_SW_CERT_STATUS_B */
    return (ssl3_do_write(s, SSL3_RT_HANDSHAKE));
}

#ifndef OPENSSL_NO_NEXTPROTONEG
/*
 * ssl3_get_next_proto reads a Next Protocol Negotiation handshake message.
 * It sets the next_proto member in s if found
 */
int ssl3_get_next_proto(SSL *s)
{
    int ok;
    unsigned int proto_len, padding_len;
    long n;
    PACKET pkt;

    /*
     * Clients cannot send a NextProtocol message if we didn't see the
     * extension in their ClientHello
     */
    if (!s->s3->next_proto_neg_seen) {
        SSLerr(SSL_F_SSL3_GET_NEXT_PROTO,
               SSL_R_GOT_NEXT_PROTO_WITHOUT_EXTENSION);
        s->state = SSL_ST_ERR;
        return -1;
    }

    /* See the payload format below */
    n = s->method->ssl_get_message(s,
                                   SSL3_ST_SR_NEXT_PROTO_A,
                                   SSL3_ST_SR_NEXT_PROTO_B,
                                   SSL3_MT_NEXT_PROTO, 514, &ok);

    if (!ok)
        return ((int)n);

    /*
     * s->state doesn't reflect whether ChangeCipherSpec has been received in
     * this handshake, but s->s3->change_cipher_spec does (will be reset by
     * ssl3_get_finished).
     */
    if (!s->s3->change_cipher_spec) {
        SSLerr(SSL_F_SSL3_GET_NEXT_PROTO, SSL_R_GOT_NEXT_PROTO_BEFORE_A_CCS);
        s->state = SSL_ST_ERR;
        return -1;
    }

    if (n < 2) {
        goto err;               /* The body must be > 1 bytes long */
    }

    if (!PACKET_buf_init(&pkt, s->init_msg, n)) {
        SSLerr(SSL_F_SSL3_GET_NEXT_PROTO, ERR_R_INTERNAL_ERROR);
        goto err;
    }

    /*-
     * The payload looks like:
     *   uint8 proto_len;
     *   uint8 proto[proto_len];
     *   uint8 padding_len;
     *   uint8 padding[padding_len];
     */
    if (!PACKET_get_1(&pkt, &proto_len)){
        SSLerr(SSL_F_SSL3_GET_NEXT_PROTO, SSL_R_LENGTH_MISMATCH);
        goto err;
    }

    s->next_proto_negotiated = OPENSSL_malloc(proto_len);
    if (s->next_proto_negotiated == NULL) {
        SSLerr(SSL_F_SSL3_GET_NEXT_PROTO, ERR_R_MALLOC_FAILURE);
        goto err;
    }

    if (!PACKET_copy_bytes(&pkt, s->next_proto_negotiated, proto_len)
            || !PACKET_get_1(&pkt, &padding_len)
            || PACKET_remaining(&pkt) != padding_len) {
        OPENSSL_free(s->next_proto_negotiated);
        s->next_proto_negotiated = NULL;
        SSLerr(SSL_F_SSL3_GET_NEXT_PROTO, SSL_R_LENGTH_MISMATCH);
        goto err;
    }

    return 1;
err:
    s->state = SSL_ST_ERR;
    return 0;
}
#endif

#define SSLV2_CIPHER_LEN    3

STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s, unsigned char *p,
                                               int num,
                                               STACK_OF(SSL_CIPHER) **skp,
                                               int sslv2format)
{
    const SSL_CIPHER *c;
    STACK_OF(SSL_CIPHER) *sk;
    int i, n;

    if (s->s3)
        s->s3->send_connection_binding = 0;

    if(sslv2format) {
        n = SSLV2_CIPHER_LEN;
    } else {
        n = ssl_put_cipher_by_char(s, NULL, NULL);
    }
    if (n == 0 || (num % n) != 0) {
        SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,
               SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST);
        return (NULL);
    }
    if ((skp == NULL) || (*skp == NULL)) {
        sk = sk_SSL_CIPHER_new_null(); /* change perhaps later */
        if(sk == NULL) {
            SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST, ERR_R_MALLOC_FAILURE);
            return NULL;
        }
    } else {
        sk = *skp;
        sk_SSL_CIPHER_zero(sk);
    }

    OPENSSL_free(s->s3->tmp.ciphers_raw);
    s->s3->tmp.ciphers_raw = BUF_memdup(p, num);
    if (s->s3->tmp.ciphers_raw == NULL) {
        SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST, ERR_R_MALLOC_FAILURE);
        goto err;
    }
    s->s3->tmp.ciphers_rawlen = (size_t)num;

    for (i = 0; i < num; i += n) {
        /* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV */
        if (s->s3 && (n != 3 || !p[0]) &&
            (p[n - 2] == ((SSL3_CK_SCSV >> 8) & 0xff)) &&
            (p[n - 1] == (SSL3_CK_SCSV & 0xff))) {
            /* SCSV fatal if renegotiating */
            if (s->renegotiate) {
                SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,
                       SSL_R_SCSV_RECEIVED_WHEN_RENEGOTIATING);
                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
                goto err;
            }
            s->s3->send_connection_binding = 1;
            p += n;
#ifdef OPENSSL_RI_DEBUG
            fprintf(stderr, "SCSV received by server\n");
#endif
            continue;
        }

        /* Check for TLS_FALLBACK_SCSV */
        if ((n != 3 || !p[0]) &&
            (p[n - 2] == ((SSL3_CK_FALLBACK_SCSV >> 8) & 0xff)) &&
            (p[n - 1] == (SSL3_CK_FALLBACK_SCSV & 0xff))) {
            /*
             * The SCSV indicates that the client previously tried a higher
             * version. Fail if the current version is an unexpected
             * downgrade.
             */
            if (!SSL_ctrl(s, SSL_CTRL_CHECK_PROTO_VERSION, 0, NULL)) {
                SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST,
                       SSL_R_INAPPROPRIATE_FALLBACK);
                if (s->s3)
                    ssl3_send_alert(s, SSL3_AL_FATAL,
                                    SSL_AD_INAPPROPRIATE_FALLBACK);
                goto err;
            }
            p += n;
            continue;
        }

        if(sslv2format) {
            /*
             * We only support SSLv2 format ciphers in SSLv3+ using a
             * SSLv2 backward compatible ClientHello. In this case the first
             * byte is always 0 for SSLv3 compatible ciphers. Anything else
             * is an SSLv2 cipher and we ignore it
             */
            if(p[0] == 0)
                c = ssl_get_cipher_by_char(s, &p[1]);
            else
                c = NULL;
        } else {
            c = ssl_get_cipher_by_char(s, p);
        }
        p += n;
        if (c != NULL) {
            if (!sk_SSL_CIPHER_push(sk, c)) {
                SSLerr(SSL_F_SSL_BYTES_TO_CIPHER_LIST, ERR_R_MALLOC_FAILURE);
                goto err;
            }
        }
    }

    if (skp != NULL)
        *skp = sk;
    return (sk);
 err:
    if ((skp == NULL) || (*skp == NULL))
        sk_SSL_CIPHER_free(sk);
    return (NULL);
}