s3_enc.c

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/* ssl/s3_enc.c */
/* Copyright (C) 1995-1998 Eric Young ([e-mail])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([e-mail]).
 * 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 ([e-mail]).
 * 
 * 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 ([e-mail])"
 *    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 ([e-mail])"
 * 
 * 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.]
 */

#include <stdio.h>
#include <openssl/md5.h>
#include <openssl/sha.h>
#include <openssl/evp.h>
#include "ssl_locl.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 void ssl3_generate_key_block(SSL *s, unsigned char *km, int num)
	{
	MD5_CTX m5;
	SHA_CTX s1;
	unsigned char buf[8],smd[SHA_DIGEST_LENGTH];
	unsigned char c='A';
	int i,j,k;

#ifdef CHARSET_EBCDIC
	c = os_toascii[c]; /*'A' in ASCII */
#endif
	k=0;
	for (i=0; i<num; i+=MD5_DIGEST_LENGTH)
		{
		k++;
		for (j=0; j<k; j++)
			buf[j]=c;
		c++;
		SHA1_Init(  &s1);
		SHA1_Update(&s1,buf,k);
		SHA1_Update(&s1,s->session->master_key,
			s->session->master_key_length);
		SHA1_Update(&s1,s->s3->server_random,SSL3_RANDOM_SIZE);
		SHA1_Update(&s1,s->s3->client_random,SSL3_RANDOM_SIZE);
		SHA1_Final( smd,&s1);

		MD5_Init(  &m5);
		MD5_Update(&m5,s->session->master_key,
			s->session->master_key_length);
		MD5_Update(&m5,smd,SHA_DIGEST_LENGTH);
		if ((i+MD5_DIGEST_LENGTH) > num)
			{
			MD5_Final(smd,&m5);
			memcpy(km,smd,(num-i));
			}
		else
			MD5_Final(km,&m5);

		km+=MD5_DIGEST_LENGTH;
		}
	memset(smd,0,SHA_DIGEST_LENGTH);
	}

int ssl3_change_cipher_state(SSL *s, int which)
	{
	unsigned char *p,*key_block,*mac_secret;
	unsigned char exp_key[EVP_MAX_KEY_LENGTH];
	unsigned char exp_iv[EVP_MAX_KEY_LENGTH];
	unsigned char *ms,*key,*iv,*er1,*er2;
	EVP_CIPHER_CTX *dd;
	const EVP_CIPHER *c;
	COMP_METHOD *comp;
	const EVP_MD *m;
	MD5_CTX md;
	int exp,n,i,j,k,cl;

	exp=SSL_C_IS_EXPORT(s->s3->tmp.new_cipher);
	c=s->s3->tmp.new_sym_enc;
	m=s->s3->tmp.new_hash;
	if (s->s3->tmp.new_compression == NULL)
		comp=NULL;
	else
		comp=s->s3->tmp.new_compression->method;
	key_block=s->s3->tmp.key_block;

	if (which & SSL3_CC_READ)
		{
		if ((s->enc_read_ctx == NULL) &&
			((s->enc_read_ctx=(EVP_CIPHER_CTX *)
			OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL))
			goto err;
		dd= s->enc_read_ctx;
		s->read_hash=m;
		/* 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;
			}
		memset(&(s->s3->read_sequence[0]),0,8);
		mac_secret= &(s->s3->read_mac_secret[0]);
		}
	else
		{
		if ((s->enc_write_ctx == NULL) &&
			((s->enc_write_ctx=(EVP_CIPHER_CTX *)
			OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL))
			goto err;
		dd= s->enc_write_ctx;
		s->write_hash=m;
		/* 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;
				}
			}
		memset(&(s->s3->write_sequence[0]),0,8);
		mac_secret= &(s->s3->write_mac_secret[0]);
		}

	EVP_CIPHER_CTX_init(dd);

	p=s->s3->tmp.key_block;
	i=EVP_MD_size(m);
	cl=EVP_CIPHER_key_length(c);
	j=exp ? (cl < SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher) ?
		 cl : SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher)) : cl;
	/* Was j=(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,SSL_R_INTERNAL_ERROR);
		goto err2;
		}

	memcpy(mac_secret,ms,i);
	if (exp)
		{
		/* In here I set both the read and write key/iv to the
		 * same value since only the correct one will be used :-).
		 */
		MD5_Init(&md);
		MD5_Update(&md,key,j);
		MD5_Update(&md,er1,SSL3_RANDOM_SIZE);
		MD5_Update(&md,er2,SSL3_RANDOM_SIZE);
		MD5_Final(&(exp_key[0]),&md);
		key= &(exp_key[0]);

		if (k > 0)
			{
			MD5_Init(&md);
			MD5_Update(&md,er1,SSL3_RANDOM_SIZE);
			MD5_Update(&md,er2,SSL3_RANDOM_SIZE);
			MD5_Final(&(exp_iv[0]),&md);
			iv= &(exp_iv[0]);
			}
		}

	s->session->key_arg_length=0;

	EVP_CipherInit(dd,c,key,iv,(which & SSL3_CC_WRITE));

	memset(&(exp_key[0]),0,sizeof(exp_key));
	memset(&(exp_iv[0]),0,sizeof(exp_iv));
	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;
	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);
		}