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/* $OpenBSD: cipher-bf1.c,v 1.5 2006/08/03 03:34:42 deraadt Exp $ */

/*

 * Copyright (c) 2003 Markus Friedl.  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.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.

 */

#include "includes.h"

#include <sys/types.h>

#include <openssl/evp.h>

#include <stdarg.h>

#include <string.h>

#include "xmalloc.h"

#include "log.h"

#include "openbsd-compat/openssl-compat.h"

/*

 * SSH1 uses a variation on Blowfish, all bytes must be swapped before

 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).

 */

const EVP_CIPHER * evp_ssh1_bf(void);

static void

swap_bytes(const u_char *src, u_char *dst, int n)

{

	u_char c[4];

	/* Process 4 bytes every lap. */

	for (n = n / 4; n > 0; n--) {

		c[3] = *src++;

		c[2] = *src++;

		c[1] = *src++;

		c[0] = *src++;

		*dst++ = c[0];

		*dst++ = c[1];

		*dst++ = c[2];

		*dst++ = c[3];

	}

}

#ifdef SSH_OLD_EVP

static void bf_ssh1_init (EVP_CIPHER_CTX * ctx, const unsigned char *key,

			  const unsigned char *iv, int enc)

{

	if (iv != NULL)

		memcpy (&(ctx->oiv[0]), iv, 8);

	memcpy (&(ctx->iv[0]), &(ctx->oiv[0]), 8);

	if (key != NULL)

		BF_set_key (&(ctx->c.bf_ks), EVP_CIPHER_CTX_key_length (ctx),

			    key);

}

#endif

static int (*orig_bf)(EVP_CIPHER_CTX *, u_char *, const u_char *, u_int) = NULL;

static int

bf_ssh1_cipher(EVP_CIPHER_CTX *ctx, u_char *out, const u_char *in, u_int len)

{

	int ret;

	swap_bytes(in, out, len);

	ret = (*orig_bf)(ctx, out, out, len);

	swap_bytes(out, out, len);

	return (ret);

}

const EVP_CIPHER *

evp_ssh1_bf(void)

{

	static EVP_CIPHER ssh1_bf;

	memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));

	orig_bf = ssh1_bf.do_cipher;

	ssh1_bf.nid = NID_undef;

#ifdef SSH_OLD_EVP

	ssh1_bf.init = bf_ssh1_init;

#endif

	ssh1_bf.do_cipher = bf_ssh1_cipher;

	ssh1_bf.key_len = 32;

	return (&ssh1_bf);

}