path: root/ssl/s3_enc.c

/* ssl/s3_enc.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) 1998-2002 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/evp.h>
#include <openssl/md5.h>

static unsigned char ssl3_pad_1[48]={
	0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
	0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
	0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
	0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
	0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
	0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36 };

static unsigned char ssl3_pad_2[48]={
	0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
	0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
	0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
	0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
	0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
	0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c };

static int ssl3_handshake_mac(SSL *s, EVP_MD_CTX *in_ctx,
	const char *sender, int len, unsigned char *p);

static int ssl3_generate_key_block(SSL *s, unsigned char *km, int num)
	{
	EVP_MD_CTX m5;
	EVP_MD_CTX s1;
	unsigned char buf[16],smd[SHA_DIGEST_LENGTH];
	unsigned char c='A';
	unsigned int i,j,k;

#ifdef CHARSET_EBCDIC
	c = os_toascii[c]; /*'A' in ASCII */
#endif
	k=0;
	EVP_MD_CTX_init(&m5);
	EVP_MD_CTX_set_flags(&m5, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
	EVP_MD_CTX_init(&s1);
	for (i=0; (int)i<num; i+=MD5_DIGEST_LENGTH)
		{
		k++;
		if (k > sizeof buf)
			{
			/* bug: 'buf' is too small for this ciphersuite */
			SSLerr(SSL_F_SSL3_GENERATE_KEY_BLOCK, ERR_R_INTERNAL_ERROR);
			return 0;
			}
		
		for (j=0; j<k; j++)
			buf[j]=c;
		c++;
		EVP_DigestInit_ex(&s1,EVP_sha1(), NULL);
		EVP_DigestUpdate(&s1,buf,k);
		EVP_DigestUpdate(&s1,s->session->master_key,
			s->session->master_key_length);
		EVP_DigestUpdate(&s1,s->s3->server_random,SSL3_RANDOM_SIZE);
		EVP_DigestUpdate(&s1,s->s3->client_random,SSL3_RANDOM_SIZE);
		EVP_DigestFinal_ex(&s1,smd,NULL);

		EVP_DigestInit_ex(&m5,EVP_md5(), NULL);
		EVP_DigestUpdate(&m5,s->session->master_key,
			s->session->master_key_length);
		EVP_DigestUpdate(&m5,smd,SHA_DIGEST_LENGTH);
		if ((int)(i+MD5_DIGEST_LENGTH) > num)
			{
			EVP_DigestFinal_ex(&m5,smd,NULL);
			memcpy(km,smd,(num-i));
			}
		else
			EVP_DigestFinal_ex(&m5,km,NULL);

		km+=MD5_DIGEST_LENGTH;
		}
	OPENSSL_cleanse(smd,SHA_DIGEST_LENGTH);
	EVP_MD_CTX_cleanup(&m5);
	EVP_MD_CTX_cleanup(&s1);
	return 1;
	}

int ssl3_change_cipher_state(SSL *s, int which)
	{
	unsigned char *p,*mac_secret;
	unsigned char exp_key[EVP_MAX_KEY_LENGTH];
	unsigned char exp_iv[EVP_MAX_IV_LENGTH];
	unsigned char *ms,*key,*iv,*er1,*er2;
	EVP_CIPHER_CTX *dd;
	const EVP_CIPHER *c;
#ifndef OPENSSL_NO_COMP
	COMP_METHOD *comp;
#endif
	const EVP_MD *m;
	EVP_MD_CTX md;
	int is_exp,n,i,j,k,cl;
	int reuse_dd = 0;

	is_exp=SSL_C_IS_EXPORT(s->s3->tmp.new_cipher);
	c=s->s3->tmp.new_sym_enc;
	m=s->s3->tmp.new_hash;
#ifndef OPENSSL_NO_COMP
	if (s->s3->tmp.new_compression == NULL)
		comp=NULL;
	else
		comp=s->s3->tmp.new_compression->method;
#endif

	if (which & SSL3_CC_READ)
		{
		if (s->enc_read_ctx != NULL)
			reuse_dd = 1;
		else if ((s->enc_read_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
			goto err;
		else
			/* make sure it's intialized in case we exit later with an error */
			EVP_CIPHER_CTX_init(s->enc_read_ctx);
		dd= s->enc_read_ctx;
		s->read_hash=m;
#ifndef OPENSSL_NO_COMP
		/* COMPRESS */
		if (s->expand != NULL)
			{
			COMP_CTX_free(s->expand);
			s->expand=NULL;
			}
		if (comp != NULL)
			{
			s->expand=COMP_CTX_new(comp);
			if (s->expand == NULL)
				{
				SSLerr(SSL_F_SSL3_CHANGE_CIPHER_STATE,SSL_R_COMPRESSION_LIBRARY_ERROR);
				goto err2;
				}
			if (s->s3->rrec.comp == NULL)
				s->s3->rrec.comp=(unsigned char *)
					OPENSSL_malloc(SSL3_RT_MAX_PLAIN_LENGTH);
			if (s->s3->rrec.comp == NULL)
				goto err;
			}
#endif
		memset(&(s->s3->read_sequence[0]),0,8);
		mac_secret= &(s->s3->read_mac_secret[0]);
		}
	else
		{
		if (s->enc_write_ctx != NULL)
			reuse_dd = 1;
		else if ((s->enc_write_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
			goto err;
		else
			/* make sure it's intialized in case we exit later with an error */
			EVP_CIPHER_CTX_init(s->enc_write_ctx);
		dd= s->enc_write_ctx;
		s->write_hash=m;
#ifndef OPENSSL_NO_COMP
		/* COMPRESS */
		if (s->compress != NULL)
			{
			COMP_CTX_free(s->compress);
			s->compress=NULL;
			}
		if (comp != NULL)
			{
			s->compress=COMP_CTX_new(comp);
			if (s->compress == NULL)
				{
				SSLerr(SSL_F_SSL3_CHANGE_CIPHER_STATE,SSL_R_COMPRESSION_LIBRARY_ERROR);
				goto err2;
				}
			}
#endif
		memset(&(s->s3->write_sequence[0]),0,8);
		mac_secret= &(s->s3->write_mac_secret[0]);
		}

	if (reuse_dd)
		EVP_CIPHER_CTX_cleanup(dd);

	p=s->s3->tmp.key_block;
	i=EVP_MD_size(m);
	cl=EVP_CIPHER_key_length(c);
	j=is_exp ? (cl < SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher) ?
		 cl : SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher)) : cl;
	/* Was j=(is_exp)?5:EVP_CIPHER_key_length(c); */
	k=EVP_CIPHER_iv_length(c);
	if (	(which == SSL3_CHANGE_CIPHER_CLIENT_WRITE) ||
		(which == SSL3_CHANGE_CIPHER_SERVER_READ))
		{
		ms=  &(p[ 0]); n=i+i;
		key= &(p[ n]); n+=j+j;
		iv=  &(p[ n]); n+=k+k;
		er1= &(s->s3->client_random[0]);
		er2= &(s->s3->server_random[0]);
		}
	else
		{
		n=i;
		ms=  &(p[ n]); n+=i+j;
		key= &(p[ n]); n+=j+k;
		iv=  &(p[ n]); n+=k;
		er1= &(s->s3->server_random[0]);
		er2= &(s->s3->client_random[0]);
		}

	if (n > s->s3->tmp.key_block_length)
		{
		SSLerr(SSL_F_SSL3_CHANGE_CIPHER_STATE,ERR_R_INTERNAL_ERROR);
		goto err2;
		}

	EVP_MD_CTX_init(&md);
	memcpy(mac_secret,ms,i);
	if (is_exp)
		{
		/* In here I set both the read and write key/iv to the
		 * same value since only the correct one will be used :-).
		 */
		EVP_DigestInit_ex(&md,EVP_md5(), NULL);
		EVP_DigestUpdate(&md,key,j);
		EVP_DigestUpdate(&md,er1,SSL3_RANDOM_SIZE);
		EVP_DigestUpdate(&md,er2,SSL3_RANDOM_SIZE);
		EVP_DigestFinal_ex(&md,&(exp_key[0]),NULL);
		key= &(exp_key[0]);

		if (k > 0)
			{
			EVP_DigestInit_ex(&md,EVP_md5(), NULL);
			EVP_DigestUpdate(&md,er1,SSL3_RANDOM_SIZE);
			EVP_DigestUpdate(&md,er2,SSL3_RANDOM_SIZE);
			EVP_DigestFinal_ex(&md,&(exp_iv[0]),NULL);
			iv= &(exp_iv[0]);
			}
		}

	s->session->key_arg_length=0;

	EVP_CipherInit_ex(dd,c,NULL,key,iv,(which & SSL3_CC_WRITE));

	OPENSSL_cleanse(&(exp_key[0]),sizeof(exp_key));
	OPENSSL_cleanse(&(exp_iv[0]),sizeof(exp_iv));
	EVP_MD_CTX_cleanup(&md);
	return(1);
err:
	SSLerr(SSL_F_SSL3_CHANGE_CIPHER_STATE,ERR_R_MALLOC_FAILURE);
err2:
	return(0);
	}

int ssl3_setup_key_block(SSL *s)
	{
	unsigned char *p;
	const EVP_CIPHER *c;
	const EVP_MD *hash;
	int num;
	int ret = 0;
	SSL_COMP *comp;

	if (s->s3->tmp.key_block_length != 0)
		return(1);

	if (!ssl_cipher_get_evp(s->session,&c,&hash,&comp))
		{
		SSLerr(SSL_F_SSL3_SETUP_KEY_BLOCK,SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
		return(0);
		}

	s->s3->tmp.new_sym_enc=c;
	s->s3->tmp.new_hash=hash;
#ifdef OPENSSL_NO_COMP
	s->s3->tmp.new_compression=NULL;
#else
	s->s3->tmp.new_compression=comp;
#endif

	num=EVP_CIPHER_key_length(c)+EVP_MD_size(hash)+EVP_CIPHER_iv_length(c);
	num*=2;

	ssl3_cleanup_key_block(s);

	if ((p=OPENSSL_malloc(num)) == NULL)
		goto err;

	s->s3->tmp.key_block_length=num;
	s->s3->tmp.key_block=p;

	ret = ssl3_generate_key_block(s,p,num);

	if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS))
		{
		/* enable vulnerability countermeasure for CBC ciphers with
		 * known-IV problem (http://www.openssl.org/~bodo/tls-cbc.txt)
		 */
		s->s3->need_empty_fragments = 1;

		if (s->session->cipher != NULL)
			{
			if ((s->session->cipher->algorithms & SSL_ENC_MASK) == SSL_eNULL)
				s->s3->need_empty_fragments = 0;
			
#ifndef OPENSSL_NO_RC4
			if ((s->session->cipher->algorithms & SSL_ENC_MASK) == SSL_RC4)
				s->s3->need_empty_fragments = 0;
#endif
			}
		}

	return ret;
		
err:
	SSLerr(SSL_F_SSL3_SETUP_KEY_BLOCK,ERR_R_MALLOC_FAILURE);
	return(0);
	}

void ssl3_cleanup_key_block(SSL *s)
	{
	if (s->s3->tmp.key_block != NULL)
		{
		OPENSSL_cleanse(s->s3->tmp.key_block,
			s->s3->tmp.key_block_length);
		OPENSSL_free(s->s3->tmp.key_block);
		s->s3->tmp.key_block=NULL;
		}
	s->s3->tmp.key_block_length=0;
	}

/* ssl3_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
 *
 * Returns:
 *   0: (in non-constant time) if the record is publically invalid (i.e. too
 *       short etc).
 *   1: if the record's padding is valid / the encryption was successful.
 *   -1: if the record's padding is invalid or, if sending, an internal error
 *       occured.
 */
int ssl3_enc(SSL *s, int send)
	{
	SSL3_RECORD *rec;
	EVP_CIPHER_CTX *ds;
	unsigned long l;
	int bs,i,mac_size=0;
	const EVP_CIPHER *enc;

	if (send)
		{
		ds=s->enc_write_ctx;
		rec= &(s->s3->wrec);
		if (s->enc_write_ctx == NULL)
			enc=NULL;
		else
			enc=EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
		}
	else
		{
		ds=s->enc_read_ctx;
		rec= &(s->s3->rrec);
		if (s->enc_read_ctx == NULL)
			enc=NULL;
		else
			enc=EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
		}

	if ((s->session == NULL) || (ds == NULL) ||
		(enc == NULL))
		{
		memmove(rec->data,rec->input,rec->length);
		rec->input=rec->data;
		}
	else
		{
		l=rec->length;
		bs=EVP_CIPHER_block_size(ds->cipher);

		/* COMPRESS */

		if ((bs != 1) && send)
			{
			i=bs-((int)l%bs);

			/* we need to add 'i-1' padding bytes */
			l+=i;
			/* the last of these zero bytes will be overwritten
			 * with the padding length. */
			memset(&rec->input[rec->length], 0, i);
			rec->length+=i;
			rec->input[l-1]=(i-1);
			}
		
		if (!send)
			{
			if (l == 0 || l%bs != 0)
				return 0;
			/* otherwise, rec->length >= bs */
			}
		
		EVP_Cipher(ds,rec->data,rec->input,l);

		rec->orig_len = rec->length;

		if (s->read_hash != NULL)
			mac_size = EVP_MD_size(s->read_hash);

		if ((bs != 1) && !send)
			return ssl3_cbc_remove_padding(s, rec, bs, mac_size);
		}
	return(1);
	}

void ssl3_init_finished_mac(SSL *s)
	{
	EVP_MD_CTX_set_flags(&(s->s3->finish_dgst1),
		EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
	EVP_DigestInit_ex(&(s->s3->finish_dgst1),s->ctx->md5, NULL);
	EVP_DigestInit_ex(&(s->s3->finish_dgst2),s->ctx->sha1, NULL);
	}

void ssl3_finish_mac(SSL *s, const unsigned char *buf, int len)
	{
	EVP_DigestUpdate(&(s->s3->finish_dgst1),buf,len);
	EVP_DigestUpdate(&(s->s3->finish_dgst2),buf,len);
	}

int ssl3_cert_verify_mac(SSL *s, EVP_MD_CTX *ctx, unsigned char *p)
	{
	return(ssl3_handshake_mac(s,ctx,NULL,0,p));
	}

int ssl3_final_finish_mac(SSL *s, EVP_MD_CTX *ctx1, EVP_MD_CTX *ctx2,
	     const char *sender, int len, unsigned char *p)
	{
	int ret;

	ret=ssl3_handshake_mac(s,ctx1,sender,len,p);
	p+=ret;
	ret+=ssl3_handshake_mac(s,ctx2,sender,len,p);
	return(ret);
	}

static int ssl3_handshake_mac(SSL *s, EVP_MD_CTX *in_ctx,
	     const char *sender, int len, unsigned char *p)
	{
	unsigned int ret;
	int npad,n;
	unsigned int i;
	unsigned char md_buf[EVP_MAX_MD_SIZE];
	EVP_MD_CTX ctx;

	EVP_MD_CTX_init(&ctx);
	EVP_MD_CTX_set_flags(&ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
	EVP_MD_CTX_copy_ex(&ctx,in_ctx);

	n=EVP_MD_CTX_size(&ctx);
	npad=(48/n)*n;

	if (sender != NULL)
		EVP_DigestUpdate(&ctx,sender,len);
	EVP_DigestUpdate(&ctx,s->session->master_key,
		s->session->master_key_length);
	EVP_DigestUpdate(&ctx,ssl3_pad_1,npad);
	EVP_DigestFinal_ex(&ctx,md_buf,&i);

	EVP_DigestInit_ex(&ctx,EVP_MD_CTX_md(&ctx), NULL);
	EVP_DigestUpdate(&ctx,s->session->master_key,
		s->session->master_key_length);
	EVP_DigestUpdate(&ctx,ssl3_pad_2,npad);
	EVP_DigestUpdate(&ctx,md_buf,i);
	EVP_DigestFinal_ex(&ctx,p,&ret);

	EVP_MD_CTX_cleanup(&ctx);

	return((int)ret);
	}

int ssl3_mac(SSL *ssl, unsigned char *md, int send)
	{
	SSL3_RECORD *rec;
	unsigned char *mac_sec,*seq;
	EVP_MD_CTX md_ctx;
	const EVP_MD *hash;
	unsigned char *p,rec_char;
	size_t md_size;
	int npad;

	if (send)
		{
		rec= &(ssl->s3->wrec);
		mac_sec= &(ssl->s3->write_mac_secret[0]);
		seq= &(ssl->s3->write_sequence[0]);
		hash=ssl->write_hash;
		}
	else
		{
		rec= &(ssl->s3->rrec);
		mac_sec= &(ssl->s3->read_mac_secret[0]);
		seq= &(ssl->s3->read_sequence[0]);
		hash=ssl->read_hash;
		}

	md_size=EVP_MD_size(hash);
	npad=(48/md_size)*md_size;

	if (!send &&
	    EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE &&
	    ssl3_cbc_record_digest_supported(hash))
		{
		/* This is a CBC-encrypted record. We must avoid leaking any
		 * timing-side channel information about how many blocks of
		 * data we are hashing because that gives an attacker a
		 * timing-oracle. */

		/* npad is, at most, 48 bytes and that's with MD5:
		 *   16 + 48 + 8 (sequence bytes) + 1 + 2 = 75.
		 *
		 * With SHA-1 (the largest hash speced for SSLv3) the hash size
		 * goes up 4, but npad goes down by 8, resulting in a smaller
		 * total size. */
		unsigned char header[75];
		unsigned j = 0;
		memcpy(header+j, mac_sec, md_size);
		j += md_size;
		memcpy(header+j, ssl3_pad_1, npad);
		j += npad;
		memcpy(header+j, seq, 8);
		j += 8;
		header[j++] = rec->type;
		header[j++] = rec->length >> 8;
		header[j++] = rec->length & 0xff;

		ssl3_cbc_digest_record(
			hash,
			md, &md_size,
			header, rec->input,
			rec->length + md_size, rec->orig_len,
			mac_sec, md_size,
			1 /* is SSLv3 */);
		}
	else
		{
		unsigned int md_size_u;
		/* Chop the digest off the end :-) */
		EVP_MD_CTX_init(&md_ctx);

		EVP_DigestInit_ex( &md_ctx,hash, NULL);
		EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
		EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
		EVP_DigestUpdate(&md_ctx,seq,8);
		rec_char=rec->type;
		EVP_DigestUpdate(&md_ctx,&rec_char,1);
		p=md;
		s2n(rec->length,p);
		EVP_DigestUpdate(&md_ctx,md,2);
		EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
		EVP_DigestFinal_ex( &md_ctx,md,NULL);

		EVP_DigestInit_ex( &md_ctx,hash, NULL);
		EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
		EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
		EVP_DigestUpdate(&md_ctx,md,md_size);
		EVP_DigestFinal_ex( &md_ctx,md,&md_size_u);
		md_size = md_size_u;

		EVP_MD_CTX_cleanup(&md_ctx);
	}

	ssl3_record_sequence_update(seq);
	return(md_size);
	}

void ssl3_record_sequence_update(unsigned char *seq)
	{
	int i;

	for (i=7; i>=0; i--)
		{
		++seq[i];
		if (seq[i] != 0) break; 
		}
	}

int ssl3_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
	     int len)
	{
	static const unsigned char *salt[3]={
#ifndef CHARSET_EBCDIC
		(const unsigned char *)"A",
		(const unsigned char *)"BB",
		(const unsigned char *)"CCC",
#else
		(const unsigned char *)"\x41",
		(const unsigned char *)"\x42\x42",
		(const unsigned char *)"\x43\x43\x43",
#endif
		};
	unsigned char buf[EVP_MAX_MD_SIZE];
	EVP_MD_CTX ctx;
	int i,ret=0;
	unsigned int n;

	EVP_MD_CTX_init(&ctx);
	for (i=0; i<3; i++)
		{
		EVP_DigestInit_ex(&ctx,s->ctx->sha1, NULL);
		EVP_DigestUpdate(&ctx,salt[i],strlen((const char *)salt[i]));
		EVP_DigestUpdate(&ctx,p,len);
		EVP_DigestUpdate(&ctx,&(s->s3->client_random[0]),
			SSL3_RANDOM_SIZE);
		EVP_DigestUpdate(&ctx,&(s->s3->server_random[0]),
			SSL3_RANDOM_SIZE);
		EVP_DigestFinal_ex(&ctx,buf,&n);

		EVP_DigestInit_ex(&ctx,s->ctx->md5, NULL);
		EVP_DigestUpdate(&ctx,p,len);
		EVP_DigestUpdate(&ctx,buf,n);
		EVP_DigestFinal_ex(&ctx,out,&n);
		out+=n;
		ret+=n;
		}
	EVP_MD_CTX_cleanup(&ctx);
	return(ret);
	}

int ssl3_alert_code(int code)
	{
	switch (code)
		{
	case SSL_AD_CLOSE_NOTIFY:	return(SSL3_AD_CLOSE_NOTIFY);
	case SSL_AD_UNEXPECTED_MESSAGE:	return(SSL3_AD_UNEXPECTED_MESSAGE);
	case SSL_AD_BAD_RECORD_MAC:	return(SSL3_AD_BAD_RECORD_MAC);
	case SSL_AD_DECRYPTION_FAILED:	return(SSL3_AD_BAD_RECORD_MAC);
	case SSL_AD_RECORD_OVERFLOW:	return(SSL3_AD_BAD_RECORD_MAC);
	case SSL_AD_DECOMPRESSION_FAILURE:return(SSL3_AD_DECOMPRESSION_FAILURE);
	case SSL_AD_HANDSHAKE_FAILURE:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_NO_CERTIFICATE:	return(SSL3_AD_NO_CERTIFICATE);
	case SSL_AD_BAD_CERTIFICATE:	return(SSL3_AD_BAD_CERTIFICATE);
	case SSL_AD_UNSUPPORTED_CERTIFICATE:return(SSL3_AD_UNSUPPORTED_CERTIFICATE);
	case SSL_AD_CERTIFICATE_REVOKED:return(SSL3_AD_CERTIFICATE_REVOKED);
	case SSL_AD_CERTIFICATE_EXPIRED:return(SSL3_AD_CERTIFICATE_EXPIRED);
	case SSL_AD_CERTIFICATE_UNKNOWN:return(SSL3_AD_CERTIFICATE_UNKNOWN);
	case SSL_AD_ILLEGAL_PARAMETER:	return(SSL3_AD_ILLEGAL_PARAMETER);
	case SSL_AD_UNKNOWN_CA:		return(SSL3_AD_BAD_CERTIFICATE);
	case SSL_AD_ACCESS_DENIED:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_DECODE_ERROR:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_DECRYPT_ERROR:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_EXPORT_RESTRICTION:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_PROTOCOL_VERSION:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_INSUFFICIENT_SECURITY:return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_INTERNAL_ERROR:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_USER_CANCELLED:	return(SSL3_AD_HANDSHAKE_FAILURE);
	case SSL_AD_NO_RENEGOTIATION:	return(-1); /* Don't send it :-) */
	default:			return(-1);
		}
	}