s2_enc.c

mediastreamer2是开源的网络传输媒体流的库

/* ssl/s2_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 "ssl_locl.h"
#ifndef OPENSSL_NO_SSL2
#include <stdio.h>

int ssl2_enc_init(SSL *s, int client)
	{
	/* Max number of bytes needed */
	EVP_CIPHER_CTX *rs,*ws;
	const EVP_CIPHER *c;
	const EVP_MD *md;
	int num;

	if (!ssl_cipher_get_evp(s->session,&c,&md,NULL))
		{
		ssl2_return_error(s,SSL2_PE_NO_CIPHER);
		SSLerr(SSL_F_SSL2_ENC_INIT,SSL_R_PROBLEMS_MAPPING_CIPHER_FUNCTIONS);
		return(0);
		}

	s->read_hash=md;
	s->write_hash=md;

	if ((s->enc_read_ctx == NULL) &&
		((s->enc_read_ctx=(EVP_CIPHER_CTX *)
		OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL))
		goto err;
	if ((s->enc_write_ctx == NULL) &&
		((s->enc_write_ctx=(EVP_CIPHER_CTX *)
		OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL))
		goto err;

	rs= s->enc_read_ctx;
	ws= s->enc_write_ctx;

	EVP_CIPHER_CTX_init(rs);
	EVP_CIPHER_CTX_init(ws);

	num=c->key_len;
	s->s2->key_material_length=num*2;
	OPENSSL_assert(s->s2->key_material_length <= sizeof s->s2->key_material);

	if (ssl2_generate_key_material(s) <= 0)
		return 0;

	OPENSSL_assert(c->iv_len <= (int)sizeof(s->session->key_arg));
	EVP_EncryptInit_ex(ws,c,NULL,&(s->s2->key_material[(client)?num:0]),
		s->session->key_arg);
	EVP_DecryptInit_ex(rs,c,NULL,&(s->s2->key_material[(client)?0:num]),
		s->session->key_arg);
	s->s2->read_key=  &(s->s2->key_material[(client)?0:num]);
	s->s2->write_key= &(s->s2->key_material[(client)?num:0]);
	return(1);
err:
	SSLerr(SSL_F_SSL2_ENC_INIT,ERR_R_MALLOC_FAILURE);
	return(0);
	}

/* read/writes from s->s2->mac_data using length for encrypt and 
 * decrypt.  It sets s->s2->padding and s->[rw]length
 * if we are encrypting */
void ssl2_enc(SSL *s, int send)
	{
	EVP_CIPHER_CTX *ds;
	unsigned long l;
	int bs;

	if (send)
		{
		ds=s->enc_write_ctx;
		l=s->s2->wlength;
		}
	else
		{
		ds=s->enc_read_ctx;
		l=s->s2->rlength;
		}

	/* check for NULL cipher */
	if (ds == NULL) return;


	bs=ds->cipher->block_size;
	/* This should be using (bs-1) and bs instead of 7 and 8, but
	 * what the hell. */
	if (bs == 8)
		l=(l+7)/8*8;

	EVP_Cipher(ds,s->s2->mac_data,s->s2->mac_data,l);
	}

void ssl2_mac(SSL *s, unsigned char *md, int send)
	{
	EVP_MD_CTX c;
	unsigned char sequence[4],*p,*sec,*act;
	unsigned long seq;
	unsigned int len;

	if (send)
		{
		seq=s->s2->write_sequence;
		sec=s->s2->write_key;
		len=s->s2->wact_data_length;
		act=s->s2->wact_data;
		}
	else
		{
		seq=s->s2->read_sequence;
		sec=s->s2->read_key;
		len=s->s2->ract_data_length;
		act=s->s2->ract_data;
		}

	p= &(sequence[0]);
	l2n(seq,p);

	/* There has to be a MAC algorithm. */
	EVP_MD_CTX_init(&c);
	EVP_DigestInit_ex(&c, s->read_hash, NULL);
	EVP_DigestUpdate(&c,sec,
		EVP_CIPHER_CTX_key_length(s->enc_read_ctx));
	EVP_DigestUpdate(&c,act,len); 
	/* the above line also does the pad data */
	EVP_DigestUpdate(&c,sequence,4); 
	EVP_DigestFinal_ex(&c,md,NULL);
	EVP_MD_CTX_cleanup(&c);
	}
#else /* !OPENSSL_NO_SSL2 */

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

#endif