s3_srvr.c

/* ssl/s3_srvr.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.]
 */

#define REUSE_CIPHER_BUG

#include <stdio.h>
#include "buffer.h"
#include "rand.h"
#include "objects.h"
#include "evp.h"
#include "x509.h"
#include "ssl_locl.h"

#define BREAK	break
/* SSLerr(SSL_F_SSL3_ACCEPT,ERR_R_MALLOC_FAILURE);
 * SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,ERR_R_MALLOC_FAILURE);
 * SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,ERR_R_MALLOC_FAILURE);
 * SSLerr(SSL_F_SSL3_GET_CERT_VERIFY,ERR_R_MALLOC_FAILURE);
 * SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,ERR_R_MALLOC_FAILURE);
 */

#ifndef NOPROTO
static SSL_METHOD *ssl3_get_server_method(int ver);
static int ssl3_get_client_hello(SSL *s);
static int ssl3_send_server_hello(SSL *s);
static int ssl3_send_server_key_exchange(SSL *s);
static int ssl3_send_certificate_request(SSL *s);
static int ssl3_send_server_done(SSL *s);
static int ssl3_get_cert_verify(SSL *s);
static int ssl3_get_client_key_exchange(SSL *s);
static int ssl3_get_client_certificate(SSL *s);
static int ssl3_send_hello_request(SSL *s);

#else

static SSL_METHOD *ssl3_get_server_method();
static int ssl3_get_client_hello();
static int ssl3_send_server_hello();
static int ssl3_send_server_key_exchange();
static int ssl3_send_certificate_request();
static int ssl3_send_server_done();
static int ssl3_get_cert_verify();
static int ssl3_get_client_key_exchange();
static int ssl3_get_client_certificate();
static int ssl3_send_hello_request();

#endif

static SSL_METHOD *ssl3_get_server_method(int ver)
	{
	if (ver == SSL3_VERSION)
		return(SSLv3_server_method());
	else
		return(NULL);
	}

SSL_METHOD *SSLv3_server_method(void)
	{
	static int init=1;
	static SSL_METHOD SSLv3_server_data;

	if (init)
		{
		memcpy((char *)&SSLv3_server_data,(char *)sslv3_base_method(),
			sizeof(SSL_METHOD));
		SSLv3_server_data.ssl_accept=ssl3_accept;
		SSLv3_server_data.get_ssl_method=ssl3_get_server_method;
		init=0;
		}
	return(&SSLv3_server_data);
	}

int ssl3_accept(SSL *s)
	{
	BUF_MEM *buf;
	unsigned long l,Time=time(NULL);
	void (*cb)()=NULL;
	long num1;
	int ret= -1;
	CERT *ct;
	int new_state,state,skip=0;

	RAND_seed(&Time,sizeof(Time));
	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 */
	if (!SSL_in_init(s) || SSL_in_before(s)) SSL_clear(s);
	s->in_handshake++;

#ifdef undef
	/* FIX THIS EAY EAY EAY */
	/* we don't actually need a cert, we just need a cert or a DH_tmp */
	if (((s->session == NULL) || (s->session->cert == NULL)) &&
		(s->cert == NULL))
		{
		SSLerr(SSL_F_SSL3_ACCEPT,SSL_R_NO_CERTIFICATE_SET);
		ret= -1;
		goto end;
		}
#endif

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

		switch (s->state)
			{
		case SSL_ST_RENEGOTIATE:
			s->new_session=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)
				abort();
			/* s->version=SSL3_VERSION; */
			s->type=SSL_ST_ACCEPT;

			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;
				}

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

			/* 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; goto end; }

			s->init_num=0;

			if (s->state != SSL_ST_RENEGOTIATE)
				{
				s->state=SSL3_ST_SR_CLNT_HELLO_A;
				ssl3_init_finished_mac(s);
				s->ctx->stats.sess_accept++;
				}
			else
				{
				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;
			ret=1;
			goto end;
			/* break; */

		case SSL3_ST_SR_CLNT_HELLO_A:
		case SSL3_ST_SR_CLNT_HELLO_B:
		case SSL3_ST_SR_CLNT_HELLO_C:

			s->shutdown=0;
			ret=ssl3_get_client_hello(s);
			if (ret <= 0) goto end;
			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)
				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 */
			if (!(s->s3->tmp.new_cipher->algorithms & SSL_aNULL))
				{
				ret=ssl3_send_server_certificate(s);
				if (ret <= 0) goto end;
				}
			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:
			l=s->s3->tmp.new_cipher->algorithms;
			if (s->session->cert == NULL)
				{
				if (s->cert != NULL)
					{
					CRYPTO_add(&s->cert->references,1,CRYPTO_LOCK_SSL_CERT);
					s->session->cert=s->cert;
					}
				else
					{
					CRYPTO_add(&s->ctx->default_cert->references,1,CRYPTO_LOCK_SSL_CERT);
					s->session->cert=s->ctx->default_cert;
					}
				}
			ct=s->session->cert;

			/* clear this, it may get reset by
			 * send_server_key_exchange */
			if (s->options & SSL_OP_EPHEMERAL_RSA)
				s->s3->tmp.use_rsa_tmp=1;
			else
				s->s3->tmp.use_rsa_tmp=0;

			/* only send if a DH key exchange, fortezza or
			 * RSA but we have a sign only certificate */
			if (s->s3->tmp.use_rsa_tmp
			    || (l & (SSL_DH|SSL_kFZA))
			    || ((l & SSL_kRSA)
				&& (ct->pkeys[SSL_PKEY_RSA_ENC].privatekey == NULL
				    || (SSL_IS_EXPORT(l)
					&& EVP_PKEY_size(ct->pkeys[SSL_PKEY_RSA_ENC].privatekey)*8 > SSL_EXPORT_PKEYLENGTH(l)
					)
				    )
				)
			    )
				{
				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 (!(s->verify_mode & SSL_VERIFY_PEER) ||
				((s->session->peer != NULL) &&
				 (s->verify_mode & SSL_VERIFY_CLIENT_ONCE)))
				{
				/* no cert request */
				skip=1;
				s->s3->tmp.cert_request=0;
				s->state=SSL3_ST_SW_SRVR_DONE_A;
				}
			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:
			/* number of bytes to be flushed */
			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;
				}

			s->state=s->s3->tmp.next_state;
			break;

		case SSL3_ST_SR_CERT_A:
		case SSL3_ST_SR_CERT_B:
			/* could be sent for a DH cert, even if we
			 * have not asked for it :-) */
			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;
			s->state=SSL3_ST_SR_CERT_VRFY_A;
			s->init_num=0;

			/* We need to get hashes here so if there is
			 * a client cert, it can be verified */ 
			s->method->ssl3_enc->cert_verify_mac(s,
				&(s->s3->finish_dgst1),
				&(s->s3->tmp.finish_md[0]));
			s->method->ssl3_enc->cert_verify_mac(s,
				&(s->s3->finish_dgst2),
				&(s->s3->tmp.finish_md[MD5_DIGEST_LENGTH]));

			break;

		case SSL3_ST_SR_CERT_VRFY_A:
		case SSL3_ST_SR_CERT_VRFY_B:

			/* we should decide if we expected this one */
			ret=ssl3_get_cert_verify(s);
			if (ret <= 0) goto end;

			s->state=SSL3_ST_SR_FINISHED_A;
			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
				s->state=SSL3_ST_SW_CHANGE_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; 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;
				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,
				s->method->ssl3_enc->server_finished_len);
			if (ret <= 0) goto end;
			s->state=SSL3_ST_SW_FLUSH;
			if (s->hit)
				s->s3->tmp.next_state=SSL3_ST_SR_FINISHED_A;
			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->new_session=0;
			s->init_num=0;

			ssl_update_cache(s,SSL_SESS_CACHE_SERVER);

			s->ctx->stats.sess_accept_good++;
			/* s->server=1; */
			s->handshake_func=ssl3_accept;
			ret=1;

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

			goto end;
			/* break; */

		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); */

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

static int ssl3_send_hello_request(SSL *s)
	{
	unsigned char *p;

	if (s->state == SSL3_ST_SW_HELLO_REQ_A)
		{
		p=(unsigned char *)s->init_buf->data;
		*(p++)=SSL3_MT_CLIENT_REQUEST;
		*(p++)=0;
		*(p++)=0;
		*(p++)=0;

		s->state=SSL3_ST_SW_HELLO_REQ_B;
		/* number of bytes to write */
		s->init_num=4;
		s->init_off=0;
		}

	/* SSL3_ST_SW_HELLO_REQ_B */
	return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
	}

static int ssl3_get_client_hello(SSL *s)
	{
	int i,j,ok,al,ret= -1;
	long n;
	unsigned long id;
	unsigned char *p,*d,*q;
	SSL_CIPHER *c;
	SSL_COMP *comp=NULL;
	STACK_OF(SSL_CIPHER) *ciphers=NULL;

	/* 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->first_packet=1;
		s->state=SSL3_ST_SR_CLNT_HELLO_B;
		}
	n=ssl3_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);
	d=p=(unsigned char *)s->init_buf->data;

	/* The version number has already been checked in ssl3_get_message.
	 * I a native TLSv1/SSLv3 method, the match must be correct except
	 * perhaps for the first message */
/*	s->client_version=(((int)p[0])<<8)|(int)p[1]; */
	p+=2;

	/* load the client random */
	memcpy(s->s3->client_random,p,SSL3_RANDOM_SIZE);
	p+=SSL3_RANDOM_SIZE;

	/* get the session-id */
	j= *(p++);

	s->hit=0;
	if (j == 0)
		{
		if (!ssl_get_new_session(s,1))
			goto err;
		}
	else
		{
		i=ssl_get_prev_session(s,p,j);
		if (i == 1)
			{ /* previous session */
			s->hit=1;
			}
		else
			{
			if (!ssl_get_new_session(s,1))
				goto err;
			}
		}

	p+=j;
	n2s(p,i);
	if ((i == 0) && (j != 0))
		{
		/* we need a cipher if we are not resuming a session */
		al=SSL_AD_ILLEGAL_PARAMETER;
		SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_NO_CIPHERS_SPECIFIED);
		goto f_err;
		}
	if ((i+p) > (d+n))
		{
		/* not enough data */
		al=SSL_AD_DECODE_ERROR;
		SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_LENGTH_MISMATCH);
		goto f_err;
		}
	if ((i > 0) && (ssl_bytes_to_cipher_list(s,p,i,&(ciphers))
		== NULL))
		{
		goto err;
		}
	p+=i;

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

#ifdef CIPHER_DEBUG
		printf("client sent %d ciphers\n",sk_num(ciphers));
#endif
		for (i=0; i<sk_SSL_CIPHER_num(ciphers); i++)
			{
			c=sk_SSL_CIPHER_value(ciphers,i);
#ifdef CIPHER_DEBUG
			printf("client [%2d of %2d]:%s\n",
				i,sk_num(ciphers),SSL_CIPHER_get_name(c));
#endif
			if (c->id == id)
				{
				j=1;
				break;
				}
			}
		if (j == 0)
			{
			if ((s->options & SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG) && (sk_SSL_CIPHER_num(ciphers) == 1))
				{
				/* Very bad for multi-threading.... */
				s->session->cipher=sk_SSL_CIPHER_value(ciphers,
								       0);
				}
			else
				{
				/* 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 */
	i= *(p++);
	q=p;
	for (j=0; j<i; j++)
		{
		if (p[j] == 0) break;
		}

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

	/* Worst case, we will use the NULL compression, but if we have other
	 * options, we will now look for them.  We have i-1 compression
	 * algorithms from the client, starting at q. */
	s->s3->tmp.new_compression=NULL;
	if (s->ctx->comp_methods != NULL)
		{ /* See if we have a match */
		int m,nn,o,v,done=0;

		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<i; o++)
				{
				if (v == q[o])
					{
					done=1;
					break;
					}
				}
			if (done) break;
			}
		if (done)
			s->s3->tmp.new_compression=comp;
		else
			comp=NULL;
		}

	/* TLS does not mind if there is extra stuff */
	if (s->version == SSL3_VERSION)
		{
		if (p > (d+n))
			{
			/* wrong number of bytes,
			 * there could be more to follow */
			al=SSL_AD_DECODE_ERROR;
			SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_LENGTH_MISMATCH);
			goto f_err;
			}
		}

	/* Given s->session->ciphers and ssl_get_ciphers_by_id(s), we must
	 * pick a cipher */

	if (!s->hit)
		{
		s->session->compress_meth=(comp == NULL)?0:comp->id;
		if (s->session->ciphers != NULL)
			sk_SSL_CIPHER_free(s->session->ciphers);
		s->session->ciphers=ciphers;
		if (ciphers == NULL)
			{
			al=SSL_AD_ILLEGAL_PARAMETER;
			SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO,SSL_R_NO_CIPHERS_PASSED);
			goto f_err;
			}
		ciphers=NULL;
		c=ssl3_choose_cipher(s,s->session->ciphers,
				     ssl_get_ciphers_by_id(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;
		}
	else
		{
		/* Session-id reuse */
#ifdef REUSE_CIPHER_BUG
		STACK_OF(SSL_CIPHER) *sk;
		SSL_CIPHER *nc=NULL;
		SSL_CIPHER *ec=NULL;

		if (s->options & SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG)
			{
			sk=s->session->ciphers;
			for (i=0; i<sk_SSL_CIPHER_num(sk); i++)
				{
				c=sk_SSL_CIPHER_value(sk,i);
				if (c->algorithms & SSL_eNULL)
					nc=c;
				if (SSL_C_IS_EXPORT(c))
					ec=c;
				}
			if (nc != NULL)
				s->s3->tmp.new_cipher=nc;
			else if (ec != NULL)
				s->s3->tmp.new_cipher=ec;
			else
				s->s3->tmp.new_cipher=s->session->cipher;
			}
		else
#endif
		s->s3->tmp.new_cipher=s->session->cipher;
		}
	
	/* 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		- sesson reuse flag
	 * s->tmp.new_cipher	- the new cipher to use.
	 */

	ret=1;
	if (0)
		{
f_err:
		ssl3_send_alert(s,SSL3_AL_FATAL,al);
		}
err:
	if (ciphers != NULL) sk_SSL_CIPHER_free(ciphers);
	return(ret);
	}

static int ssl3_send_server_hello(SSL *s)
	{
	unsigned char *buf;
	unsigned char *p,*d;
	int i,sl;
	unsigned long l,Time;

	if (s->state == SSL3_ST_SW_SRVR_HELLO_A)
		{
		buf=(unsigned char *)s->init_buf->data;
		p=s->s3->server_random;
		Time=time(NULL);			/* Time */
		l2n(Time,p);
		RAND_bytes(p,SSL3_RANDOM_SIZE-sizeof(Time));
		/* Do the message type and length last */
		d=p= &(buf[4]);

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

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

		/* now in theory we have 3 options to sending back the
		 * session id.  If it is a re-use, we send back the
		 * old session-id, if it is a new session, we send
		 * back the new session-id or we send back a 0 length
		 * session-id if we want it to be single use.
		 * Currently I will not implement the '0' length session-id
		 * 12-Jan-98 - I'll now support the '0' length stuff.
		 */
		if (!(s->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER))
			s->session->session_id_length=0;

		sl=s->session->session_id_length;
		*(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 */
		if (s->s3->tmp.new_compression == NULL)
			*(p++)=0;
		else
			*(p++)=s->s3->tmp.new_compression->id;

		/* do the header */
		l=(p-d);
		d=buf;
		*(d++)=SSL3_MT_SERVER_HELLO;
		l2n3(l,d);

		s->state=SSL3_ST_CW_CLNT_HELLO_B;
		/* number of bytes to write */
		s->init_num=p-buf;
		s->init_off=0;
		}

	/* SSL3_ST_CW_CLNT_HELLO_B */
	return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
	}

static int ssl3_send_server_done(SSL *s)
	{
	unsigned char *p;

	if (s->state == SSL3_ST_SW_SRVR_DONE_A)
		{
		p=(unsigned char *)s->init_buf->data;

		/* do the header */
		*(p++)=SSL3_MT_SERVER_DONE;
		*(p++)=0;
		*(p++)=0;
		*(p++)=0;

		s->state=SSL3_ST_SW_SRVR_DONE_B;
		/* number of bytes to write */
		s->init_num=4;
		s->init_off=0;
		}

	/* SSL3_ST_CW_CLNT_HELLO_B */
	return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
	}

static int ssl3_send_server_key_exchange(SSL *s)
	{
#ifndef NO_RSA
	unsigned char *q;
	int j,num;
	RSA *rsa;
	unsigned char md_buf[MD5_DIGEST_LENGTH+SHA_DIGEST_LENGTH];
#endif
#ifndef NO_DH
	DH *dh,*dhp;
#endif
	EVP_PKEY *pkey;
	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;

	if (s->state == SSL3_ST_SW_KEY_EXCH_A)
		{
		type=s->s3->tmp.new_cipher->algorithms & SSL_MKEY_MASK;
		cert=s->session->cert;

		buf=s->init_buf;

		r[0]=r[1]=r[2]=r[3]=NULL;
		n=0;
#ifndef NO_RSA
		if (type & SSL_kRSA)
			{
			rsa=cert->rsa_tmp;
			if ((rsa == NULL) && (s->ctx->default_cert->rsa_tmp_cb != NULL))
				{
				rsa=s->ctx->default_cert->rsa_tmp_cb(s,
				      SSL_C_IS_EXPORT(s->s3->tmp.new_cipher),
				      SSL_C_EXPORT_PKEYLENGTH(s->s3->tmp.new_cipher));
				CRYPTO_add(&rsa->references,1,CRYPTO_LOCK_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 NO_DH
			if (type & SSL_kEDH)
			{
			dhp=cert->dh_tmp;
			if ((dhp == NULL) && (cert->dh_tmp_cb != NULL))
				dhp=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 ((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;
					}
				}