s2_srvr.c

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/* ssl/s2_srvr.c */
/* Copyright (C) 1995-1998 Eric Young ([email protected])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([email protected]).
 * 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 ([email protected]).
 * 
 * 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 ([email protected])"
 *    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 ([email protected])"
 * 
 * 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) 1998-2001 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
 *    [email protected].
 *
 * 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
 * ([email protected]).  This product includes software written by Tim
 * Hudson ([email protected]).
 *
 */

#include "ssl_locl.h"
#ifndef OPENSSL_NO_SSL2
#include <stdio.h>
#include <openssl/bio.h>
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/evp.h>

static const SSL_METHOD *ssl2_get_server_method(int ver);
static int get_client_master_key(SSL *s);
static int get_client_hello(SSL *s);
static int server_hello(SSL *s); 
static int get_client_finished(SSL *s);
static int server_verify(SSL *s);
static int server_finish(SSL *s);
static int request_certificate(SSL *s);
static int ssl_rsa_private_decrypt(CERT *c, int len, unsigned char *from,
    unsigned char *to,int padding);
#define BREAK   break

static const SSL_METHOD *ssl2_get_server_method(int ver)
    {
    if (ver == SSL2_VERSION)
        return(SSLv2_server_method());
    else
        return(NULL);
    }

IMPLEMENT_ssl2_meth_func(SSLv2_server_method,
            ssl2_accept,
            ssl_undefined_function,
            ssl2_get_server_method)

int ssl2_accept(SSL *s)
    {
    unsigned long l=(unsigned long)time(NULL);
    BUF_MEM *buf=NULL;
    int ret= -1;
    long num1;
    void (*cb)(const SSL *ssl,int type,int val)=NULL;
    int new_state,state;

    RAND_add(&l,sizeof(l),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)) SSL_clear(s);

    if (s->cert == NULL)
        {
        SSLerr(SSL_F_SSL2_ACCEPT,SSL_R_NO_CERTIFICATE_SET);
        return(-1);
        }

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

        switch (s->state)
            {
        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);

            s->version=SSL2_VERSION;
            s->type=SSL_ST_ACCEPT;

            buf=s->init_buf;
            if ((buf == NULL) && ((buf=BUF_MEM_new()) == NULL))
                { ret= -1; goto end; }
            if (!BUF_MEM_grow(buf,(int)
                SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER))
                { ret= -1; goto end; }
            s->init_buf=buf;
            s->init_num=0;
            s->ctx->stats.sess_accept++;
            s->handshake_func=ssl2_accept;
            s->state=SSL2_ST_GET_CLIENT_HELLO_A;
            BREAK;

        case SSL2_ST_GET_CLIENT_HELLO_A:
        case SSL2_ST_GET_CLIENT_HELLO_B:
        case SSL2_ST_GET_CLIENT_HELLO_C:
            s->shutdown=0;
            ret=get_client_hello(s);
            if (ret <= 0) goto end;
            s->init_num=0;
            s->state=SSL2_ST_SEND_SERVER_HELLO_A;
            BREAK;

        case SSL2_ST_SEND_SERVER_HELLO_A:
        case SSL2_ST_SEND_SERVER_HELLO_B:
            ret=server_hello(s);
            if (ret <= 0) goto end;
            s->init_num=0;
            if (!s->hit)
                {
                s->state=SSL2_ST_GET_CLIENT_MASTER_KEY_A;
                BREAK;
                }
            else
                {
                s->state=SSL2_ST_SERVER_START_ENCRYPTION;
                BREAK;
                }
        case SSL2_ST_GET_CLIENT_MASTER_KEY_A:
        case SSL2_ST_GET_CLIENT_MASTER_KEY_B:
            ret=get_client_master_key(s);
            if (ret <= 0) goto end;
            s->init_num=0;
            s->state=SSL2_ST_SERVER_START_ENCRYPTION;
            BREAK;

        case SSL2_ST_SERVER_START_ENCRYPTION:
            /* Ok we how have sent all the stuff needed to
             * start encrypting, the next packet back will
             * be encrypted. */
            if (!ssl2_enc_init(s,0))
                { ret= -1; goto end; }
            s->s2->clear_text=0;
            s->state=SSL2_ST_SEND_SERVER_VERIFY_A;
            BREAK;

        case SSL2_ST_SEND_SERVER_VERIFY_A:
        case SSL2_ST_SEND_SERVER_VERIFY_B:
            ret=server_verify(s);
            if (ret <= 0) goto end;
            s->init_num=0;
            if (s->hit)
                {
                /* If we are in here, we have been
                 * buffering the output, so we need to
                 * flush it and remove buffering from
                 * future traffic */
                s->state=SSL2_ST_SEND_SERVER_VERIFY_C;
                BREAK;
                }
            else
                {
                s->state=SSL2_ST_GET_CLIENT_FINISHED_A;
                break;
                }

        case SSL2_ST_SEND_SERVER_VERIFY_C:
            /* get the number of bytes to write */
            num1=BIO_ctrl(s->wbio,BIO_CTRL_INFO,0,NULL);
            if (num1 > 0)
                {
                s->rwstate=SSL_WRITING;
                num1=BIO_flush(s->wbio);
                if (num1 <= 0) { ret= -1; goto end; }
                s->rwstate=SSL_NOTHING;
                }

            /* flushed and now remove buffering */
            s->wbio=BIO_pop(s->wbio);

            s->state=SSL2_ST_GET_CLIENT_FINISHED_A;
            BREAK;

        case SSL2_ST_GET_CLIENT_FINISHED_A:
        case SSL2_ST_GET_CLIENT_FINISHED_B:
            ret=get_client_finished(s);
            if (ret <= 0)
                goto end;
            s->init_num=0;
            s->state=SSL2_ST_SEND_REQUEST_CERTIFICATE_A;
            BREAK;

        case SSL2_ST_SEND_REQUEST_CERTIFICATE_A:
        case SSL2_ST_SEND_REQUEST_CERTIFICATE_B:
        case SSL2_ST_SEND_REQUEST_CERTIFICATE_C:
        case SSL2_ST_SEND_REQUEST_CERTIFICATE_D:
            /* don't do a 'request certificate' if we
             * don't want to, or we already have one, and
             * we only want to do it once. */
            if (!(s->verify_mode & SSL_VERIFY_PEER) ||
                ((s->session->peer != NULL) &&
                (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)))
                {
                s->state=SSL2_ST_SEND_SERVER_FINISHED_A;
                break;
                }
            else
                {
                ret=request_certificate(s);
                if (ret <= 0) goto end;
                s->init_num=0;
                s->state=SSL2_ST_SEND_SERVER_FINISHED_A;
                }
            BREAK;

        case SSL2_ST_SEND_SERVER_FINISHED_A:
        case SSL2_ST_SEND_SERVER_FINISHED_B:
            ret=server_finish(s);
            if (ret <= 0) goto end;
            s->init_num=0;
            s->state=SSL_ST_OK;
            break;

        case SSL_ST_OK:
            BUF_MEM_free(s->init_buf);
            ssl_free_wbio_buffer(s);
            s->init_buf=NULL;
            s->init_num=0;
        /*  ERR_clear_error();*/

            ssl_update_cache(s,SSL_SESS_CACHE_SERVER);

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

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

            goto end;
            /* BREAK; */

        default:
            SSLerr(SSL_F_SSL2_ACCEPT,SSL_R_UNKNOWN_STATE);
            ret= -1;
            goto end;
            /* BREAK; */
            }
        
        if ((cb != NULL) && (s->state != state))
            {
            new_state=s->state;
            s->state=state;
            cb(s,SSL_CB_ACCEPT_LOOP,1);
            s->state=new_state;
            }
        }
end:
    s->in_handshake--;
    if (cb != NULL)
        cb(s,SSL_CB_ACCEPT_EXIT,ret);
    return(ret);
    }

static int get_client_master_key(SSL *s)
    {
    int is_export,i,n,keya,ek;
    unsigned long len;
    unsigned char *p;
    const SSL_CIPHER *cp;
    const EVP_CIPHER *c;
    const EVP_MD *md;

    p=(unsigned char *)s->init_buf->data;
    if (s->state == SSL2_ST_GET_CLIENT_MASTER_KEY_A)
        {
        i=ssl2_read(s,(char *)&(p[s->init_num]),10-s->init_num);

        if (i < (10-s->init_num))
            return(ssl2_part_read(s,SSL_F_GET_CLIENT_MASTER_KEY,i));
        s->init_num = 10;

        if (*(p++) != SSL2_MT_CLIENT_MASTER_KEY)
            {
            if (p[-1] != SSL2_MT_ERROR)
                {
                ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
                SSLerr(SSL_F_GET_CLIENT_MASTER_KEY,SSL_R_READ_WRONG_PACKET_TYPE);
                }
            else
                SSLerr(SSL_F_GET_CLIENT_MASTER_KEY, SSL_R_PEER_ERROR);
            return(-1);
            }

        cp=ssl2_get_cipher_by_char(p);
        if (cp == NULL)
            {
            ssl2_return_error(s,SSL2_PE_NO_CIPHER);
            SSLerr(SSL_F_GET_CLIENT_MASTER_KEY, SSL_R_NO_CIPHER_MATCH);
            return(-1);
            }
        s->session->cipher= cp;

        p+=3;
        n2s(p,i); s->s2->tmp.clear=i;
        n2s(p,i); s->s2->tmp.enc=i;
        n2s(p,i);
        if(i > SSL_MAX_KEY_ARG_LENGTH)
            {
            ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
            SSLerr(SSL_F_GET_CLIENT_MASTER_KEY, SSL_R_KEY_ARG_TOO_LONG);
            return -1;
            }
        s->session->key_arg_length=i;
        s->state=SSL2_ST_GET_CLIENT_MASTER_KEY_B;
        }

    /* SSL2_ST_GET_CLIENT_MASTER_KEY_B */
    p=(unsigned char *)s->init_buf->data;
    if (s->init_buf->length < SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_MASTER_KEY, ERR_R_INTERNAL_ERROR);
        return -1;
        }
    keya=s->session->key_arg_length;
    len = 10 + (unsigned long)s->s2->tmp.clear + (unsigned long)s->s2->tmp.enc + (unsigned long)keya;
    if (len > SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_MASTER_KEY,SSL_R_MESSAGE_TOO_LONG);
        return -1;
        }
    n = (int)len - s->init_num;
    i = ssl2_read(s,(char *)&(p[s->init_num]),n);
    if (i != n) return(ssl2_part_read(s,SSL_F_GET_CLIENT_MASTER_KEY,i));
    if (s->msg_callback)
        s->msg_callback(0, s->version, 0, p, (size_t)len, s, s->msg_callback_arg); /* CLIENT-MASTER-KEY */
    p += 10;

    memcpy(s->session->key_arg,&(p[s->s2->tmp.clear+s->s2->tmp.enc]),
        (unsigned int)keya);

    if (s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_MASTER_KEY,SSL_R_NO_PRIVATEKEY);
        return(-1);
        }
    i=ssl_rsa_private_decrypt(s->cert,s->s2->tmp.enc,
        &(p[s->s2->tmp.clear]),&(p[s->s2->tmp.clear]),
        (s->s2->ssl2_rollback)?RSA_SSLV23_PADDING:RSA_PKCS1_PADDING);

    is_export=SSL_C_IS_EXPORT(s->session->cipher);
    
    if (!ssl_cipher_get_evp(s->session,&c,&md,NULL,NULL,NULL))
        {
        ssl2_return_error(s,SSL2_PE_NO_CIPHER);
        SSLerr(SSL_F_GET_CLIENT_MASTER_KEY,SSL_R_PROBLEMS_MAPPING_CIPHER_FUNCTIONS);
        return(0);
        }

    if (s->session->cipher->algorithm2 & SSL2_CF_8_BYTE_ENC)
        {
        is_export=1;
        ek=8;
        }
    else
        ek=5;

    /* bad decrypt */
#if 1
    /* If a bad decrypt, continue with protocol but with a
     * random master secret (Bleichenbacher attack) */
    if ((i < 0) ||
        ((!is_export && (i != EVP_CIPHER_key_length(c)))
        || (is_export && ((i != ek) || (s->s2->tmp.clear+(unsigned int)i !=
            (unsigned int)EVP_CIPHER_key_length(c))))))
        {
        ERR_clear_error();
        if (is_export)
            i=ek;
        else
            i=EVP_CIPHER_key_length(c);
        if (RAND_pseudo_bytes(p,i) <= 0)
            return 0;
        }
#else
    if (i < 0)
        {
        error=1;
        SSLerr(SSL_F_GET_CLIENT_MASTER_KEY,SSL_R_BAD_RSA_DECRYPT);
        }
    /* incorrect number of key bytes for non export cipher */
    else if ((!is_export && (i != EVP_CIPHER_key_length(c)))
        || (is_export && ((i != ek) || (s->s2->tmp.clear+i !=
            EVP_CIPHER_key_length(c)))))
        {
        error=1;
        SSLerr(SSL_F_GET_CLIENT_MASTER_KEY,SSL_R_WRONG_NUMBER_OF_KEY_BITS);
        }
    if (error)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        return(-1);
        }
#endif

    if (is_export) i+=s->s2->tmp.clear;

    if (i > SSL_MAX_MASTER_KEY_LENGTH)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_MASTER_KEY, ERR_R_INTERNAL_ERROR);
        return -1;
        }
    s->session->master_key_length=i;
    memcpy(s->session->master_key,p,(unsigned int)i);
    return(1);
    }

static int get_client_hello(SSL *s)
    {
    int i,n;
    unsigned long len;
    unsigned char *p;
    STACK_OF(SSL_CIPHER) *cs; /* a stack of SSL_CIPHERS */
    STACK_OF(SSL_CIPHER) *cl; /* the ones we want to use */
    STACK_OF(SSL_CIPHER) *prio, *allow;
    int z;

    /* This is a bit of a hack to check for the correct packet
     * type the first time round. */
    if (s->state == SSL2_ST_GET_CLIENT_HELLO_A)
        {
        s->first_packet=1;
        s->state=SSL2_ST_GET_CLIENT_HELLO_B;
        }

    p=(unsigned char *)s->init_buf->data;
    if (s->state == SSL2_ST_GET_CLIENT_HELLO_B)
        {
        i=ssl2_read(s,(char *)&(p[s->init_num]),9-s->init_num);
        if (i < (9-s->init_num)) 
            return(ssl2_part_read(s,SSL_F_GET_CLIENT_HELLO,i));
        s->init_num = 9;
    
        if (*(p++) != SSL2_MT_CLIENT_HELLO)
            {
            if (p[-1] != SSL2_MT_ERROR)
                {
                ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
                SSLerr(SSL_F_GET_CLIENT_HELLO,SSL_R_READ_WRONG_PACKET_TYPE);
                }
            else
                SSLerr(SSL_F_GET_CLIENT_HELLO,SSL_R_PEER_ERROR);
            return(-1);
            }
        n2s(p,i);
        if (i < s->version) s->version=i;
        n2s(p,i); s->s2->tmp.cipher_spec_length=i;
        n2s(p,i); s->s2->tmp.session_id_length=i;
        n2s(p,i); s->s2->challenge_length=i;
        if (    (i < SSL2_MIN_CHALLENGE_LENGTH) ||
            (i > SSL2_MAX_CHALLENGE_LENGTH))
            {
            ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
            SSLerr(SSL_F_GET_CLIENT_HELLO,SSL_R_INVALID_CHALLENGE_LENGTH);
            return(-1);
            }
        s->state=SSL2_ST_GET_CLIENT_HELLO_C;
        }

    /* SSL2_ST_GET_CLIENT_HELLO_C */
    p=(unsigned char *)s->init_buf->data;
    len = 9 + (unsigned long)s->s2->tmp.cipher_spec_length + (unsigned long)s->s2->challenge_length + (unsigned long)s->s2->tmp.session_id_length;
    if (len > SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_HELLO,SSL_R_MESSAGE_TOO_LONG);
        return -1;
        }
    n = (int)len - s->init_num;
    i = ssl2_read(s,(char *)&(p[s->init_num]),n);
    if (i != n) return(ssl2_part_read(s,SSL_F_GET_CLIENT_HELLO,i));
    if (s->msg_callback)
        s->msg_callback(0, s->version, 0, p, (size_t)len, s, s->msg_callback_arg); /* CLIENT-HELLO */
    p += 9;

    /* get session-id before cipher stuff so we can get out session
     * structure if it is cached */
    /* session-id */
    if ((s->s2->tmp.session_id_length != 0) && 
        (s->s2->tmp.session_id_length != SSL2_SSL_SESSION_ID_LENGTH))
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_HELLO,SSL_R_BAD_SSL_SESSION_ID_LENGTH);
        return(-1);
        }

    if (s->s2->tmp.session_id_length == 0)
        {
        if (!ssl_get_new_session(s,1))
            {
            ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
            return(-1);
            }
        }
    else
        {
        i=ssl_get_prev_session(s,&(p[s->s2->tmp.cipher_spec_length]),
            s->s2->tmp.session_id_length, NULL);
        if (i == 1)
            { /* previous session */
            s->hit=1;
            }
        else if (i == -1)
            {
            ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
            return(-1);
            }
        else
            {
            if (s->cert == NULL)
                {
                ssl2_return_error(s,SSL2_PE_NO_CERTIFICATE);
                SSLerr(SSL_F_GET_CLIENT_HELLO,SSL_R_NO_CERTIFICATE_SET);
                return(-1);
                }

            if (!ssl_get_new_session(s,1))
                {
                ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
                return(-1);
                }
            }
        }

    if (!s->hit)
        {
        cs=ssl_bytes_to_cipher_list(s,p,s->s2->tmp.cipher_spec_length,
            &s->session->ciphers);
        if (cs == NULL) goto mem_err;

        cl=SSL_get_ciphers(s);

        if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE)
            {
            prio=sk_SSL_CIPHER_dup(cl);
            if (prio == NULL) goto mem_err;
            allow = cs;
            }
        else
            {
            prio = cs;
            allow = cl;
            }
        for (z=0; z<sk_SSL_CIPHER_num(prio); z++)
            {
            if (sk_SSL_CIPHER_find(allow,sk_SSL_CIPHER_value(prio,z)) < 0)
                {
                (void)sk_SSL_CIPHER_delete(prio,z);
                z--;
                }
            }
        if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE)
            {
            sk_SSL_CIPHER_free(s->session->ciphers);
            s->session->ciphers = prio;
            }
        /* s->session->ciphers should now have a list of
         * ciphers that are on both the client and server.
         * This list is ordered by the order the client sent
         * the ciphers or in the order of the server's preference
         * if SSL_OP_CIPHER_SERVER_PREFERENCE was set.
         */
        }
    p+=s->s2->tmp.cipher_spec_length;
    /* done cipher selection */

    /* session id extracted already */
    p+=s->s2->tmp.session_id_length;

    /* challenge */
    if (s->s2->challenge_length > sizeof s->s2->challenge)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_HELLO, ERR_R_INTERNAL_ERROR);
        return -1;
        }
    memcpy(s->s2->challenge,p,(unsigned int)s->s2->challenge_length);
    return(1);
mem_err:
    SSLerr(SSL_F_GET_CLIENT_HELLO,ERR_R_MALLOC_FAILURE);
    return(0);
    }

static int server_hello(SSL *s)
    {
    unsigned char *p,*d;
    int n,hit;

    p=(unsigned char *)s->init_buf->data;
    if (s->state == SSL2_ST_SEND_SERVER_HELLO_A)
        {
        d=p+11;
        *(p++)=SSL2_MT_SERVER_HELLO;        /* type */
        hit=s->hit;
        *(p++)=(unsigned char)hit;
#if 1
        if (!hit)
            {
            if (s->session->sess_cert != NULL)
                /* This can't really happen because get_client_hello
                 * has called ssl_get_new_session, which does not set
                 * sess_cert. */
                ssl_sess_cert_free(s->session->sess_cert);
            s->session->sess_cert = ssl_sess_cert_new();
            if (s->session->sess_cert == NULL)
                {
                SSLerr(SSL_F_SERVER_HELLO, ERR_R_MALLOC_FAILURE);
                return(-1);
                }
            }
        /* If 'hit' is set, then s->sess_cert may be non-NULL or NULL,
         * depending on whether it survived in the internal cache
         * or was retrieved from an external cache.
         * If it is NULL, we cannot put any useful data in it anyway,
         * so we don't touch it.
         */

#else /* That's what used to be done when cert_st and sess_cert_st were
       * the same. */
        if (!hit)
            {           /* else add cert to session */
            CRYPTO_add(&s->cert->references,1,CRYPTO_LOCK_SSL_CERT);
            if (s->session->sess_cert != NULL)
                ssl_cert_free(s->session->sess_cert);
            s->session->sess_cert=s->cert;      
            }
        else    /* We have a session id-cache hit, if the
             * session-id has no certificate listed against
             * the 'cert' structure, grab the 'old' one
             * listed against the SSL connection */
            {
            if (s->session->sess_cert == NULL)
                {
                CRYPTO_add(&s->cert->references,1,
                    CRYPTO_LOCK_SSL_CERT);
                s->session->sess_cert=s->cert;
                }
            }
#endif

        if (s->cert == NULL)
            {
            ssl2_return_error(s,SSL2_PE_NO_CERTIFICATE);
            SSLerr(SSL_F_SERVER_HELLO,SSL_R_NO_CERTIFICATE_SPECIFIED);
            return(-1);
            }

        if (hit)
            {
            *(p++)=0;       /* no certificate type */
            s2n(s->version,p);  /* version */
            s2n(0,p);       /* cert len */
            s2n(0,p);       /* ciphers len */
            }
        else
            {
            /* EAY EAY */
            /* put certificate type */
            *(p++)=SSL2_CT_X509_CERTIFICATE;
            s2n(s->version,p);  /* version */
            n=i2d_X509(s->cert->pkeys[SSL_PKEY_RSA_ENC].x509,NULL);
            s2n(n,p);       /* certificate length */
            i2d_X509(s->cert->pkeys[SSL_PKEY_RSA_ENC].x509,&d);
            n=0;
            
            /* lets send out the ciphers we like in the
             * prefered order */
            n=ssl_cipher_list_to_bytes(s,s->session->ciphers,d,0);
            d+=n;
            s2n(n,p);       /* add cipher length */
            }

        /* make and send conn_id */
        s2n(SSL2_CONNECTION_ID_LENGTH,p);   /* add conn_id length */
        s->s2->conn_id_length=SSL2_CONNECTION_ID_LENGTH;
        if (RAND_pseudo_bytes(s->s2->conn_id,(int)s->s2->conn_id_length) <= 0)
            return -1;
        memcpy(d,s->s2->conn_id,SSL2_CONNECTION_ID_LENGTH);
        d+=SSL2_CONNECTION_ID_LENGTH;

        s->state=SSL2_ST_SEND_SERVER_HELLO_B;
        s->init_num=d-(unsigned char *)s->init_buf->data;
        s->init_off=0;
        }
    /* SSL2_ST_SEND_SERVER_HELLO_B */
    /* If we are using TCP/IP, the performance is bad if we do 2
     * writes without a read between them.  This occurs when
     * Session-id reuse is used, so I will put in a buffering module
     */
    if (s->hit)
        {
        if (!ssl_init_wbio_buffer(s,1)) return(-1);
        }
 
    return(ssl2_do_write(s));
    }

static int get_client_finished(SSL *s)
    {
    unsigned char *p;
    int i, n;
    unsigned long len;

    p=(unsigned char *)s->init_buf->data;
    if (s->state == SSL2_ST_GET_CLIENT_FINISHED_A)
        {
        i=ssl2_read(s,(char *)&(p[s->init_num]),1-s->init_num);
        if (i < 1-s->init_num)
            return(ssl2_part_read(s,SSL_F_GET_CLIENT_FINISHED,i));
        s->init_num += i;

        if (*p != SSL2_MT_CLIENT_FINISHED)
            {
            if (*p != SSL2_MT_ERROR)
                {
                ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
                SSLerr(SSL_F_GET_CLIENT_FINISHED,SSL_R_READ_WRONG_PACKET_TYPE);
                }
            else
                {
                SSLerr(SSL_F_GET_CLIENT_FINISHED,SSL_R_PEER_ERROR);
                /* try to read the error message */
                i=ssl2_read(s,(char *)&(p[s->init_num]),3-s->init_num);
                return ssl2_part_read(s,SSL_F_GET_SERVER_VERIFY,i);
                }
            return(-1);
            }
        s->state=SSL2_ST_GET_CLIENT_FINISHED_B;
        }

    /* SSL2_ST_GET_CLIENT_FINISHED_B */
    if (s->s2->conn_id_length > sizeof s->s2->conn_id)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_FINISHED, ERR_R_INTERNAL_ERROR);
        return -1;
        }
    len = 1 + (unsigned long)s->s2->conn_id_length;
    n = (int)len - s->init_num;
    i = ssl2_read(s,(char *)&(p[s->init_num]),n);
    if (i < n)
        {
        return(ssl2_part_read(s,SSL_F_GET_CLIENT_FINISHED,i));
        }
    if (s->msg_callback)
        s->msg_callback(0, s->version, 0, p, len, s, s->msg_callback_arg); /* CLIENT-FINISHED */
    p += 1;
    if (memcmp(p,s->s2->conn_id,s->s2->conn_id_length) != 0)
        {
        ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
        SSLerr(SSL_F_GET_CLIENT_FINISHED,SSL_R_CONNECTION_ID_IS_DIFFERENT);
        return(-1);
        }
    return(1);
    }

static int server_verify(SSL *s)
    {
    unsigned char *p;

    if (s->state == SSL2_ST_SEND_SERVER_VERIFY_A)
        {
        p=(unsigned char *)s->init_buf->data;
        *(p++)=SSL2_MT_SERVER_VERIFY;
        if (s->s2->challenge_length > sizeof s->s2->challenge)
            {
            SSLerr(SSL_F_SERVER_VERIFY, ERR_R_INTERNAL_ERROR);
            return -1;
            }
        memcpy(p,s->s2->challenge,(unsigned int)s->s2->challenge_length);
        /* p+=s->s2->challenge_length; */

        s->state=SSL2_ST_SEND_SERVER_VERIFY_B;
        s->init_num=s->s2->challenge_length+1;
        s->init_off=0;
        }
    return(ssl2_do_write(s));
    }

static int server_finish(SSL *s)
    {
    unsigned char *p;

    if (s->state == SSL2_ST_SEND_SERVER_FINISHED_A)
        {
        p=(unsigned char *)s->init_buf->data;
        *(p++)=SSL2_MT_SERVER_FINISHED;

        if (s->session->session_id_length > sizeof s->session->session_id)
            {
            SSLerr(SSL_F_SERVER_FINISH, ERR_R_INTERNAL_ERROR);
            return -1;
            }
        memcpy(p,s->session->session_id, (unsigned int)s->session->session_id_length);
        /* p+=s->session->session_id_length; */

        s->state=SSL2_ST_SEND_SERVER_FINISHED_B;
        s->init_num=s->session->session_id_length+1;
        s->init_off=0;
        }

    /* SSL2_ST_SEND_SERVER_FINISHED_B */
    return(ssl2_do_write(s));
    }

/* send the request and check the response */
static int request_certificate(SSL *s)
    {
    const unsigned char *cp;
    unsigned char *p,*p2,*buf2;
    unsigned char *ccd;
    int i,j,ctype,ret= -1;
    unsigned long len;
    X509 *x509=NULL;
    STACK_OF(X509) *sk=NULL;

    ccd=s->s2->tmp.ccl;
    if (s->state == SSL2_ST_SEND_REQUEST_CERTIFICATE_A)
        {
        p=(unsigned char *)s->init_buf->data;
        *(p++)=SSL2_MT_REQUEST_CERTIFICATE;
        *(p++)=SSL2_AT_MD5_WITH_RSA_ENCRYPTION;
        if (RAND_pseudo_bytes(ccd,SSL2_MIN_CERT_CHALLENGE_LENGTH) <= 0)
            return -1;
        memcpy(p,ccd,SSL2_MIN_CERT_CHALLENGE_LENGTH);

        s->state=SSL2_ST_SEND_REQUEST_CERTIFICATE_B;
        s->init_num=SSL2_MIN_CERT_CHALLENGE_LENGTH+2;
        s->init_off=0;
        }

    if (s->state == SSL2_ST_SEND_REQUEST_CERTIFICATE_B)
        {
        i=ssl2_do_write(s);
        if (i <= 0)
            {
            ret=i;
            goto end;
            }

        s->init_num=0;
        s->state=SSL2_ST_SEND_REQUEST_CERTIFICATE_C;
        }

    if (s->state == SSL2_ST_SEND_REQUEST_CERTIFICATE_C)
        {
        p=(unsigned char *)s->init_buf->data;
        i=ssl2_read(s,(char *)&(p[s->init_num]),6-s->init_num); /* try to read 6 octets ... */
        if (i < 3-s->init_num) /* ... but don't call ssl2_part_read now if we got at least 3
                                * (probably NO-CERTIFICATE-ERROR) */
            {
            ret=ssl2_part_read(s,SSL_F_REQUEST_CERTIFICATE,i);
            goto end;
            }
        s->init_num += i;

        if ((s->init_num >= 3) && (p[0] == SSL2_MT_ERROR))
            {
            n2s(p,i);
            if (i != SSL2_PE_NO_CERTIFICATE)
                {
                /* not the error message we expected -- let ssl2_part_read handle it */
                s->init_num -= 3;
                ret = ssl2_part_read(s,SSL_F_REQUEST_CERTIFICATE, 3);
                goto end;
                }

            if (s->msg_callback)
                s->msg_callback(0, s->version, 0, p, 3, s, s->msg_callback_arg); /* ERROR */

            /* this is the one place where we can recover from an SSL 2.0 error */

            if (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)
                {
                ssl2_return_error(s,SSL2_PE_BAD_CERTIFICATE);
                SSLerr(SSL_F_REQUEST_CERTIFICATE,SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
                goto end;
                }
            ret=1;
            goto end;
            }
        if ((*(p++) != SSL2_MT_CLIENT_CERTIFICATE) || (s->init_num < 6))
            {
            ssl2_return_error(s,SSL2_PE_UNDEFINED_ERROR);
            SSLerr(SSL_F_REQUEST_CERTIFICATE,SSL_R_SHORT_READ);
            goto end;
            }
        if (s->init_num != 6)
            {
            SSLerr(SSL_F_REQUEST_CERTIFICATE, ERR_R_INTERNAL_ERROR);
            goto end;
            }
        
        /* ok we have a response */
        /* certificate type, there is only one right now. */
        ctype= *(p++);
        if (ctype != SSL2_AT_MD5_WITH_RSA_ENCRYPTION)
            {
            ssl2_return_error(s,SSL2_PE_UNSUPPORTED_CERTIFICATE_TYPE);
            SSLerr(SSL_F_REQUEST_CERTIFICATE,SSL_R_BAD_RESPONSE_ARGUMENT);
            goto end;
            }
        n2s(p,i); s->s2->tmp.clen=i;
        n2s(p,i); s->s2->tmp.rlen=i;
        s->state=SSL2_ST_SEND_REQUEST_CERTIFICATE_D;
        }

    /* SSL2_ST_SEND_REQUEST_CERTIFICATE_D */
    p=(unsigned char *)s->init_buf->data;
    len = 6 + (unsigned long)s->s2->tmp.clen + (unsigned long)s->s2->tmp.rlen;
    if (len > SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER)
        {
        SSLerr(SSL_F_REQUEST_CERTIFICATE,SSL_R_MESSAGE_TOO_LONG);
        goto end;
        }
    j = (int)len - s->init_num;
    i = ssl2_read(s,(char *)&(p[s->init_num]),j);
    if (i < j) 
        {
        ret=ssl2_part_read(s,SSL_F_REQUEST_CERTIFICATE,i);
        goto end;
        }
    if (s->msg_callback)
        s->msg_callback(0, s->version, 0, p, len, s, s->msg_callback_arg); /* CLIENT-CERTIFICATE */
    p += 6;

    cp = p;
    x509=(X509 *)d2i_X509(NULL,&cp,(long)s->s2->tmp.clen);
    if (x509 == NULL)
        {
        SSLerr(SSL_F_REQUEST_CERTIFICATE,ERR_R_X509_LIB);
        goto msg_end;
        }

    if (((sk=sk_X509_new_null()) == NULL) || (!sk_X509_push(sk,x509)))
        {
        SSLerr(SSL_F_REQUEST_CERTIFICATE,ERR_R_MALLOC_FAILURE);
        goto msg_end;
        }

    i=ssl_verify_cert_chain(s,sk);

    if (i > 0)  /* we like the packet, now check the chksum */
        {
        EVP_MD_CTX ctx;
        EVP_PKEY *pkey=NULL;

        EVP_MD_CTX_init(&ctx);
        EVP_VerifyInit_ex(&ctx,s->ctx->rsa_md5, NULL);
        EVP_VerifyUpdate(&ctx,s->s2->key_material,
                 s->s2->key_material_length);
        EVP_VerifyUpdate(&ctx,ccd,SSL2_MIN_CERT_CHALLENGE_LENGTH);

        i=i2d_X509(s->cert->pkeys[SSL_PKEY_RSA_ENC].x509,NULL);
        buf2=OPENSSL_malloc((unsigned int)i);
        if (buf2 == NULL)
            {
            SSLerr(SSL_F_REQUEST_CERTIFICATE,ERR_R_MALLOC_FAILURE);
            goto msg_end;
            }
        p2=buf2;
        i=i2d_X509(s->cert->pkeys[SSL_PKEY_RSA_ENC].x509,&p2);
        EVP_VerifyUpdate(&ctx,buf2,(unsigned int)i);
        OPENSSL_free(buf2);

        pkey=X509_get_pubkey(x509);
        if (pkey == NULL) goto end;
        i=EVP_VerifyFinal(&ctx,cp,s->s2->tmp.rlen,pkey);
        EVP_PKEY_free(pkey);
        EVP_MD_CTX_cleanup(&ctx);

        if (i > 0)
            {
            if (s->session->peer != NULL)
                X509_free(s->session->peer);
            s->session->peer=x509;
            CRYPTO_add(&x509->references,1,CRYPTO_LOCK_X509);
            s->session->verify_result = s->verify_result;
            ret=1;
            goto end;
            }
        else
            {
            SSLerr(SSL_F_REQUEST_CERTIFICATE,SSL_R_BAD_CHECKSUM);
            goto msg_end;
            }
        }
    else
        {
msg_end:
        ssl2_return_error(s,SSL2_PE_BAD_CERTIFICATE);
        }
end:
    sk_X509_free(sk);
    X509_free(x509);
    return(ret);
    }

static int ssl_rsa_private_decrypt(CERT *c, int len, unsigned char *from,
         unsigned char *to, int padding)
    {
    RSA *rsa;
    int i;

    if ((c == NULL) || (c->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL))
        {
        SSLerr(SSL_F_SSL_RSA_PRIVATE_DECRYPT,SSL_R_NO_PRIVATEKEY);
        return(-1);
        }
    if (c->pkeys[SSL_PKEY_RSA_ENC].privatekey->type != EVP_PKEY_RSA)
        {
        SSLerr(SSL_F_SSL_RSA_PRIVATE_DECRYPT,SSL_R_PUBLIC_KEY_IS_NOT_RSA);
        return(-1);
        }
    rsa=c->pkeys[SSL_PKEY_RSA_ENC].privatekey->pkey.rsa;

    /* we have the public key */
    i=RSA_private_decrypt(len,from,to,rsa,padding);
    if (i < 0)
        SSLerr(SSL_F_SSL_RSA_PRIVATE_DECRYPT,ERR_R_RSA_LIB);
    return(i);
    }
#else /* !OPENSSL_NO_SSL2 */

# if PEDANTIC
static void *dummy=&dummy;
# endif

#endif