OpenSSL 1.0.1j

[tomato.git] / release / src-rt-6.x.4708 / router / openssl / ssl / s23_clnt.c

/* ssl/s23_clnt.c */
/* 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) 1998-2006 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).
 *
 */

#include <stdio.h>
#include "ssl_locl.h"
#include <openssl/buffer.h>
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/evp.h>

static const SSL_METHOD *ssl23_get_client_method(int ver);
static int ssl23_client_hello(SSL *s);
static int ssl23_get_server_hello(SSL *s);
static const SSL_METHOD *ssl23_get_client_method(int ver)
        {
#ifndef OPENSSL_NO_SSL2
        if (ver == SSL2_VERSION)
                return(SSLv2_client_method());
#endif
#ifndef OPENSSL_NO_SSL3
        if (ver == SSL3_VERSION)
                return(SSLv3_client_method());
#endif
        if (ver == TLS1_VERSION)
                return(TLSv1_client_method());
        else if (ver == TLS1_1_VERSION)
                return(TLSv1_1_client_method());
        else if (ver == TLS1_2_VERSION)
                return(TLSv1_2_client_method());
        else
                return(NULL);
        }

IMPLEMENT_ssl23_meth_func(SSLv23_client_method,
                        ssl_undefined_function,
                        ssl23_connect,
                        ssl23_get_client_method)

int ssl23_connect(SSL *s)
        {
        BUF_MEM *buf=NULL;
        unsigned long Time=(unsigned long)time(NULL);
        void (*cb)(const SSL *ssl,int type,int val)=NULL;
        int ret= -1;
        int new_state,state;

        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;
        
        s->in_handshake++;
        if (!SSL_in_init(s) || SSL_in_before(s)) SSL_clear(s); 

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

                switch(s->state)
                        {
                case SSL_ST_BEFORE:
                case SSL_ST_CONNECT:
                case SSL_ST_BEFORE|SSL_ST_CONNECT:
                case SSL_ST_OK|SSL_ST_CONNECT:

                        if (s->session != NULL)
                                {
                                SSLerr(SSL_F_SSL23_CONNECT,SSL_R_SSL23_DOING_SESSION_ID_REUSE);
                                ret= -1;
                                goto end;
                                }
                        s->server=0;
                        if (cb != NULL) cb(s,SSL_CB_HANDSHAKE_START,1);

                        /* s->version=TLS1_VERSION; */
                        s->type=SSL_ST_CONNECT;

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

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

                        ssl3_init_finished_mac(s);

                        s->state=SSL23_ST_CW_CLNT_HELLO_A;
                        s->ctx->stats.sess_connect++;
                        s->init_num=0;
                        break;

                case SSL23_ST_CW_CLNT_HELLO_A:
                case SSL23_ST_CW_CLNT_HELLO_B:

                        s->shutdown=0;
                        ret=ssl23_client_hello(s);
                        if (ret <= 0) goto end;
                        s->state=SSL23_ST_CR_SRVR_HELLO_A;
                        s->init_num=0;

                        break;

                case SSL23_ST_CR_SRVR_HELLO_A:
                case SSL23_ST_CR_SRVR_HELLO_B:
                        ret=ssl23_get_server_hello(s);
                        if (ret >= 0) cb=NULL;
                        goto end;
                        /* break; */

                default:
                        SSLerr(SSL_F_SSL23_CONNECT,SSL_R_UNKNOWN_STATE);
                        ret= -1;
                        goto end;
                        /* break; */
                        }

                if (s->debug) { (void)BIO_flush(s->wbio); }

                if ((cb != NULL) && (s->state != state))
                        {
                        new_state=s->state;
                        s->state=state;
                        cb(s,SSL_CB_CONNECT_LOOP,1);
                        s->state=new_state;
                        }
                }
end:
        s->in_handshake--;
        if (buf != NULL)
                BUF_MEM_free(buf);
        if (cb != NULL)
                cb(s,SSL_CB_CONNECT_EXIT,ret);
        return(ret);
        }

static int ssl23_no_ssl2_ciphers(SSL *s)
        {
        SSL_CIPHER *cipher;
        STACK_OF(SSL_CIPHER) *ciphers;
        int i;
        ciphers = SSL_get_ciphers(s);
        for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++)
                {
                cipher = sk_SSL_CIPHER_value(ciphers, i);
                if (cipher->algorithm_ssl == SSL_SSLV2)
                        return 0;
                }
        return 1;
        }

/* Fill a ClientRandom or ServerRandom field of length len. Returns <= 0
 * on failure, 1 on success. */
int ssl_fill_hello_random(SSL *s, int server, unsigned char *result, int len)
        {
        int send_time = 0;

        if (len < 4)
                return 0;
        if (server)
                send_time = (s->mode & SSL_MODE_SEND_SERVERHELLO_TIME) != 0;
        else
                send_time = (s->mode & SSL_MODE_SEND_CLIENTHELLO_TIME) != 0;
        if (send_time)
                {
                unsigned long Time = (unsigned long)time(NULL);
                unsigned char *p = result;
                l2n(Time, p);
                return RAND_pseudo_bytes(p, len-4);
                }
        else
                return RAND_pseudo_bytes(result, len);
        }

static int ssl23_client_hello(SSL *s)
        {
        unsigned char *buf;
        unsigned char *p,*d;
        int i,ch_len;
        unsigned long l;
        int ssl2_compat;
        int version = 0, version_major, version_minor;
#ifndef OPENSSL_NO_COMP
        int j;
        SSL_COMP *comp;
#endif
        int ret;
        unsigned long mask, options = s->options;

        ssl2_compat = (options & SSL_OP_NO_SSLv2) ? 0 : 1;

        if (ssl2_compat && ssl23_no_ssl2_ciphers(s))
                ssl2_compat = 0;

        /*
         * SSL_OP_NO_X disables all protocols above X *if* there are
         * some protocols below X enabled. This is required in order
         * to maintain "version capability" vector contiguous. So
         * that if application wants to disable TLS1.0 in favour of
         * TLS1>=1, it would be insufficient to pass SSL_NO_TLSv1, the
         * answer is SSL_OP_NO_TLSv1|SSL_OP_NO_SSLv3|SSL_OP_NO_SSLv2.
         */
        mask =  SSL_OP_NO_TLSv1_1|SSL_OP_NO_TLSv1
#if !defined(OPENSSL_NO_SSL3)
                |SSL_OP_NO_SSLv3
#endif
#if !defined(OPENSSL_NO_SSL2)
                |(ssl2_compat?SSL_OP_NO_SSLv2:0)
#endif
                ;
#if !defined(OPENSSL_NO_TLS1_2_CLIENT)
        version = TLS1_2_VERSION;

        if ((options & SSL_OP_NO_TLSv1_2) && (options & mask) != mask)
                version = TLS1_1_VERSION;
#else
        version = TLS1_1_VERSION;
#endif
        mask &= ~SSL_OP_NO_TLSv1_1;
        if ((options & SSL_OP_NO_TLSv1_1) && (options & mask) != mask)
                version = TLS1_VERSION;
        mask &= ~SSL_OP_NO_TLSv1;
#if !defined(OPENSSL_NO_SSL3)
        if ((options & SSL_OP_NO_TLSv1) && (options & mask) != mask)
                version = SSL3_VERSION;
        mask &= ~SSL_OP_NO_SSLv3;
#endif
#if !defined(OPENSSL_NO_SSL2)
        if ((options & SSL_OP_NO_SSLv3) && (options & mask) != mask)
                version = SSL2_VERSION;
#endif

#ifndef OPENSSL_NO_TLSEXT
        if (version != SSL2_VERSION)
                {
                /* have to disable SSL 2.0 compatibility if we need TLS extensions */

                if (s->tlsext_hostname != NULL)
                        ssl2_compat = 0;
                if (s->tlsext_status_type != -1)
                        ssl2_compat = 0;
#ifdef TLSEXT_TYPE_opaque_prf_input
                if (s->ctx->tlsext_opaque_prf_input_callback != 0 || s->tlsext_opaque_prf_input != NULL)
                        ssl2_compat = 0;
#endif
                }
#endif

        buf=(unsigned char *)s->init_buf->data;
        if (s->state == SSL23_ST_CW_CLNT_HELLO_A)
                {
#if 0
                /* don't reuse session-id's */
                if (!ssl_get_new_session(s,0))
                        {
                        return(-1);
                        }
#endif

                p=s->s3->client_random;
                if (ssl_fill_hello_random(s, 0, p, SSL3_RANDOM_SIZE) <= 0)
                        return -1;

                if (version == TLS1_2_VERSION)
                        {
                        version_major = TLS1_2_VERSION_MAJOR;
                        version_minor = TLS1_2_VERSION_MINOR;
                        }
                else if (version == TLS1_1_VERSION)
                        {
                        version_major = TLS1_1_VERSION_MAJOR;
                        version_minor = TLS1_1_VERSION_MINOR;
                        }
                else if (version == TLS1_VERSION)
                        {
                        version_major = TLS1_VERSION_MAJOR;
                        version_minor = TLS1_VERSION_MINOR;
                        }
#ifdef OPENSSL_FIPS
                else if(FIPS_mode())
                        {
                        SSLerr(SSL_F_SSL23_CLIENT_HELLO,
                                        SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE);
                        return -1;
                        }
#endif
                else if (version == SSL3_VERSION)
                        {
                        version_major = SSL3_VERSION_MAJOR;
                        version_minor = SSL3_VERSION_MINOR;
                        }
                else if (version == SSL2_VERSION)
                        {
                        version_major = SSL2_VERSION_MAJOR;
                        version_minor = SSL2_VERSION_MINOR;
                        }
                else
                        {
                        SSLerr(SSL_F_SSL23_CLIENT_HELLO,SSL_R_NO_PROTOCOLS_AVAILABLE);
                        return(-1);
                        }

                s->client_version = version;

                if (ssl2_compat)
                        {
                        /* create SSL 2.0 compatible Client Hello */

                        /* two byte record header will be written last */
                        d = &(buf[2]);
                        p = d + 9; /* leave space for message type, version, individual length fields */

                        *(d++) = SSL2_MT_CLIENT_HELLO;
                        *(d++) = version_major;
                        *(d++) = version_minor;
                        
                        /* Ciphers supported */
                        i=ssl_cipher_list_to_bytes(s,SSL_get_ciphers(s),p,0);
                        if (i == 0)
                                {
                                /* no ciphers */
                                SSLerr(SSL_F_SSL23_CLIENT_HELLO,SSL_R_NO_CIPHERS_AVAILABLE);
                                return -1;
                                }
                        s2n(i,d);
                        p+=i;
                        
                        /* put in the session-id length (zero since there is no reuse) */
#if 0
                        s->session->session_id_length=0;
#endif
                        s2n(0,d);

                        if (s->options & SSL_OP_NETSCAPE_CHALLENGE_BUG)
                                ch_len=SSL2_CHALLENGE_LENGTH;
                        else
                                ch_len=SSL2_MAX_CHALLENGE_LENGTH;

                        /* write out sslv2 challenge */
                        /* Note that ch_len must be <= SSL3_RANDOM_SIZE (32),
                           because it is one of SSL2_MAX_CHALLENGE_LENGTH (32)
                           or SSL2_MAX_CHALLENGE_LENGTH (16), but leave the
                           check in for futurproofing */
                        if (SSL3_RANDOM_SIZE < ch_len)
                                i=SSL3_RANDOM_SIZE;
                        else
                                i=ch_len;
                        s2n(i,d);
                        memset(&(s->s3->client_random[0]),0,SSL3_RANDOM_SIZE);
                        if (RAND_pseudo_bytes(&(s->s3->client_random[SSL3_RANDOM_SIZE-i]),i) <= 0)
                                return -1;

                        memcpy(p,&(s->s3->client_random[SSL3_RANDOM_SIZE-i]),i);
                        p+=i;

                        i= p- &(buf[2]);
                        buf[0]=((i>>8)&0xff)|0x80;
                        buf[1]=(i&0xff);

                        /* number of bytes to write */
                        s->init_num=i+2;
                        s->init_off=0;

                        ssl3_finish_mac(s,&(buf[2]),i);
                        }
                else
                        {
                        /* create Client Hello in SSL 3.0/TLS 1.0 format */

                        /* do the record header (5 bytes) and handshake message header (4 bytes) last */
                        d = p = &(buf[9]);
                        
                        *(p++) = version_major;
                        *(p++) = version_minor;

                        /* Random stuff */
                        memcpy(p, s->s3->client_random, SSL3_RANDOM_SIZE);
                        p += SSL3_RANDOM_SIZE;

                        /* Session ID (zero since there is no reuse) */
                        *(p++) = 0;

                        /* Ciphers supported (using SSL 3.0/TLS 1.0 format) */
                        i=ssl_cipher_list_to_bytes(s,SSL_get_ciphers(s),&(p[2]),ssl3_put_cipher_by_char);
                        if (i == 0)
                                {
                                SSLerr(SSL_F_SSL23_CLIENT_HELLO,SSL_R_NO_CIPHERS_AVAILABLE);
                                return -1;
                                }
#ifdef OPENSSL_MAX_TLS1_2_CIPHER_LENGTH
                        /* Some servers hang if client hello > 256 bytes
                         * as hack workaround chop number of supported ciphers
                         * to keep it well below this if we use TLS v1.2
                         */
                        if (TLS1_get_version(s) >= TLS1_2_VERSION
                                && i > OPENSSL_MAX_TLS1_2_CIPHER_LENGTH)
                                i = OPENSSL_MAX_TLS1_2_CIPHER_LENGTH & ~1;
#endif
                        s2n(i,p);
                        p+=i;

                        /* COMPRESSION */
#ifdef OPENSSL_NO_COMP
                        *(p++)=1;
#else
                        if ((s->options & SSL_OP_NO_COMPRESSION)
                                                || !s->ctx->comp_methods)
                                j=0;
                        else
                                j=sk_SSL_COMP_num(s->ctx->comp_methods);
                        *(p++)=1+j;
                        for (i=0; i<j; i++)
                                {
                                comp=sk_SSL_COMP_value(s->ctx->comp_methods,i);
                                *(p++)=comp->id;
                                }
#endif
                        *(p++)=0; /* Add the NULL method */

#ifndef OPENSSL_NO_TLSEXT
                        /* TLS extensions*/
                        if (ssl_prepare_clienthello_tlsext(s) <= 0)
                                {
                                SSLerr(SSL_F_SSL23_CLIENT_HELLO,SSL_R_CLIENTHELLO_TLSEXT);
                                return -1;
                                }
                        if ((p = ssl_add_clienthello_tlsext(s, p, buf+SSL3_RT_MAX_PLAIN_LENGTH)) == NULL)
                                {
                                SSLerr(SSL_F_SSL23_CLIENT_HELLO,ERR_R_INTERNAL_ERROR);
                                return -1;
                                }
#endif
                        
                        l = p-d;

                        /* fill in 4-byte handshake header */
                        d=&(buf[5]);
                        *(d++)=SSL3_MT_CLIENT_HELLO;
                        l2n3(l,d);

                        l += 4;

                        if (l > SSL3_RT_MAX_PLAIN_LENGTH)
                                {
                                SSLerr(SSL_F_SSL23_CLIENT_HELLO,ERR_R_INTERNAL_ERROR);
                                return -1;
                                }
                        
                        /* fill in 5-byte record header */
                        d=buf;
                        *(d++) = SSL3_RT_HANDSHAKE;
                        *(d++) = version_major;
                        /* Some servers hang if we use long client hellos
                         * and a record number > TLS 1.0.
                         */
                        if (TLS1_get_client_version(s) > TLS1_VERSION)
                                *(d++) = 1;
                        else
                                *(d++) = version_minor;
                        s2n((int)l,d);

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

                        ssl3_finish_mac(s,&(buf[5]), s->init_num - 5);
                        }

                s->state=SSL23_ST_CW_CLNT_HELLO_B;
                s->init_off=0;
                }

        /* SSL3_ST_CW_CLNT_HELLO_B */
        ret = ssl23_write_bytes(s);

        if ((ret >= 2) && s->msg_callback)
                {
                /* Client Hello has been sent; tell msg_callback */

                if (ssl2_compat)
                        s->msg_callback(1, SSL2_VERSION, 0, s->init_buf->data+2, ret-2, s, s->msg_callback_arg);
                else
                        s->msg_callback(1, version, SSL3_RT_HANDSHAKE, s->init_buf->data+5, ret-5, s, s->msg_callback_arg);
                }

        return ret;
        }

static int ssl23_get_server_hello(SSL *s)
        {
        char buf[8];
        unsigned char *p;
        int i;
        int n;

        n=ssl23_read_bytes(s,7);

        if (n != 7) return(n);
        p=s->packet;

        memcpy(buf,p,n);

        if ((p[0] & 0x80) && (p[2] == SSL2_MT_SERVER_HELLO) &&
                (p[5] == 0x00) && (p[6] == 0x02))
                {
#ifdef OPENSSL_NO_SSL2
                SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,SSL_R_UNSUPPORTED_PROTOCOL);
                goto err;
#else
                /* we are talking sslv2 */
                /* we need to clean up the SSLv3 setup and put in the
                 * sslv2 stuff. */
                int ch_len;

                if (s->options & SSL_OP_NO_SSLv2)
                        {
                        SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,SSL_R_UNSUPPORTED_PROTOCOL);
                        goto err;
                        }
                if (s->s2 == NULL)
                        {
                        if (!ssl2_new(s))
                                goto err;
                        }
                else
                        ssl2_clear(s);

                if (s->options & SSL_OP_NETSCAPE_CHALLENGE_BUG)
                        ch_len=SSL2_CHALLENGE_LENGTH;
                else
                        ch_len=SSL2_MAX_CHALLENGE_LENGTH;

                /* write out sslv2 challenge */
                /* Note that ch_len must be <= SSL3_RANDOM_SIZE (32), because
                   it is one of SSL2_MAX_CHALLENGE_LENGTH (32) or
                   SSL2_MAX_CHALLENGE_LENGTH (16), but leave the check in for
                   futurproofing */
                i=(SSL3_RANDOM_SIZE < ch_len)
                        ?SSL3_RANDOM_SIZE:ch_len;
                s->s2->challenge_length=i;
                memcpy(s->s2->challenge,
                        &(s->s3->client_random[SSL3_RANDOM_SIZE-i]),i);

                if (s->s3 != NULL) ssl3_free(s);

                if (!BUF_MEM_grow_clean(s->init_buf,
                        SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER))
                        {
                        SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,ERR_R_BUF_LIB);
                        goto err;
                        }

                s->state=SSL2_ST_GET_SERVER_HELLO_A;
                if (!(s->client_version == SSL2_VERSION))
                        /* use special padding (SSL 3.0 draft/RFC 2246, App. E.2) */
                        s->s2->ssl2_rollback=1;

                /* setup the 7 bytes we have read so we get them from
                 * the sslv2 buffer */
                s->rstate=SSL_ST_READ_HEADER;
                s->packet_length=n;
                s->packet= &(s->s2->rbuf[0]);
                memcpy(s->packet,buf,n);
                s->s2->rbuf_left=n;
                s->s2->rbuf_offs=0;

                /* we have already written one */
                s->s2->write_sequence=1;

                s->method=SSLv2_client_method();
                s->handshake_func=s->method->ssl_connect;
#endif
                }
        else if (p[1] == SSL3_VERSION_MAJOR &&
                 p[2] <= TLS1_2_VERSION_MINOR &&
                 ((p[0] == SSL3_RT_HANDSHAKE && p[5] == SSL3_MT_SERVER_HELLO) ||
                  (p[0] == SSL3_RT_ALERT && p[3] == 0 && p[4] == 2)))
                {
                /* we have sslv3 or tls1 (server hello or alert) */

#ifndef OPENSSL_NO_SSL3
                if ((p[2] == SSL3_VERSION_MINOR) &&
                        !(s->options & SSL_OP_NO_SSLv3))
                        {
#ifdef OPENSSL_FIPS
                        if(FIPS_mode())
                                {
                                SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,
                                        SSL_R_ONLY_TLS_ALLOWED_IN_FIPS_MODE);
                                goto err;
                                }
#endif
                        s->version=SSL3_VERSION;
                        s->method=SSLv3_client_method();
                        }
                else
#endif
                if ((p[2] == TLS1_VERSION_MINOR) &&
                        !(s->options & SSL_OP_NO_TLSv1))
                        {
                        s->version=TLS1_VERSION;
                        s->method=TLSv1_client_method();
                        }
                else if ((p[2] == TLS1_1_VERSION_MINOR) &&
                        !(s->options & SSL_OP_NO_TLSv1_1))
                        {
                        s->version=TLS1_1_VERSION;
                        s->method=TLSv1_1_client_method();
                        }
                else if ((p[2] == TLS1_2_VERSION_MINOR) &&
                        !(s->options & SSL_OP_NO_TLSv1_2))
                        {
                        s->version=TLS1_2_VERSION;
                        s->method=TLSv1_2_client_method();
                        }
                else
                        {
                        SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,SSL_R_UNSUPPORTED_PROTOCOL);
                        goto err;
                        }

                /* ensure that TLS_MAX_VERSION is up-to-date */
                OPENSSL_assert(s->version <= TLS_MAX_VERSION);

                if (p[0] == SSL3_RT_ALERT && p[5] != SSL3_AL_WARNING)
                        {
                        /* fatal alert */

                        void (*cb)(const SSL *ssl,int type,int val)=NULL;
                        int j;

                        if (s->info_callback != NULL)
                                cb=s->info_callback;
                        else if (s->ctx->info_callback != NULL)
                                cb=s->ctx->info_callback;
 
                        i=p[5];
                        if (cb != NULL)
                                {
                                j=(i<<8)|p[6];
                                cb(s,SSL_CB_READ_ALERT,j);
                                }
                        
                        if (s->msg_callback)
                                s->msg_callback(0, s->version, SSL3_RT_ALERT, p+5, 2, s, s->msg_callback_arg);

                        s->rwstate=SSL_NOTHING;
                        SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,SSL_AD_REASON_OFFSET+p[6]);
                        goto err;
                        }

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

                /* we are in this state */
                s->state=SSL3_ST_CR_SRVR_HELLO_A;

                /* put the 7 bytes we have read into the input buffer
                 * for SSLv3 */
                s->rstate=SSL_ST_READ_HEADER;
                s->packet_length=n;
                if (s->s3->rbuf.buf == NULL)
                        if (!ssl3_setup_read_buffer(s))
                                goto err;
                s->packet= &(s->s3->rbuf.buf[0]);
                memcpy(s->packet,buf,n);
                s->s3->rbuf.left=n;
                s->s3->rbuf.offset=0;

                s->handshake_func=s->method->ssl_connect;
                }
        else
                {
                SSLerr(SSL_F_SSL23_GET_SERVER_HELLO,SSL_R_UNKNOWN_PROTOCOL);
                goto err;
                }
        s->init_num=0;

        /* Since, if we are sending a ssl23 client hello, we are not
         * reusing a session-id */
        if (!ssl_get_new_session(s,0))
                goto err;

        return(SSL_connect(s));
err:
        return(-1);
        }