ttssh2/ttxssh/cipher-3des1.c

/* Imported from OpenSSH-7.5p1, TeraTerm Project */

/* $OpenBSD: cipher-3des1.c,v 1.12 2015/01/14 10:24:42 markus Exp $ */
/*
 * Copyright (c) 2003 Markus Friedl.  All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * 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 <string.h>
#include <openssl/evp.h>
#include <windows.h>

typedef unsigned int u_int;
typedef unsigned char u_char;

#include "ssherr.h"

#include "cipher-3des1.h"

/*
 * This is used by SSH1:
 *
 * What kind of triple DES are these 2 routines?
 *
 * Why is there a redundant initialization vector?
 *
 * If only iv3 was used, then, this would till effect have been
 * outer-cbc. However, there is also a private iv1 == iv2 which
 * perhaps makes differential analysis easier. On the other hand, the
 * private iv1 probably makes the CRC-32 attack ineffective. This is a
 * result of that there is no longer any known iv1 to use when
 * choosing the X block.
 */
struct ssh1_3des_ctx
{
        EVP_CIPHER_CTX  *k1, *k2, *k3;
};

static int ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, int enc)
{
        struct ssh1_3des_ctx *c;
        u_char *k1, *k2, *k3;

        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
                if ((c = calloc(1, sizeof(*c))) == NULL)
                        return 0;
                EVP_CIPHER_CTX_set_app_data(ctx, c);
        }
        if (key == NULL)
                return 1;
        if (enc == -1)
                enc = EVP_CIPHER_CTX_encrypting(ctx); // ctx->encrypt
        k1 = k2 = k3 = (u_char *) key;
        k2 += 8;
        if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
                if (enc)
                        k3 += 16;
                else
                        k1 += 16;
        }
        c->k1 = EVP_CIPHER_CTX_new();
        c->k2 = EVP_CIPHER_CTX_new();
        c->k3 = EVP_CIPHER_CTX_new();
        /*** TODO: OPENSSL1.1.1 ERROR CHECK(ticket#39335�����u�\��) ***/
        if (EVP_CipherInit(c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 ||
            EVP_CipherInit(c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 ||
            EVP_CipherInit(c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
                EVP_CIPHER_CTX_free(c->k1);
                EVP_CIPHER_CTX_free(c->k2);
                EVP_CIPHER_CTX_free(c->k3);
                SecureZeroMemory(c, sizeof(*c));
                free(c);
                EVP_CIPHER_CTX_set_app_data(ctx, NULL);
                return 0;
        }
        return 1;
}

static int ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, size_t len)
{
        struct ssh1_3des_ctx *c;

        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
                //error("ssh1_3des_cbc: no context");
                return 0;
        }
        if (EVP_Cipher(c->k1, dest, (u_char *)src, len) == 0 ||
            EVP_Cipher(c->k2, dest, dest, len) == 0 ||
            EVP_Cipher(c->k3, dest, dest, len) == 0)
                return 0;
        return 1;
}

static int ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
{
        struct ssh1_3des_ctx *c;

        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
                EVP_CIPHER_CTX_free(c->k1);
                EVP_CIPHER_CTX_free(c->k2);
                EVP_CIPHER_CTX_free(c->k3);
                SecureZeroMemory(c, sizeof(*c));
                free(c);
                EVP_CIPHER_CTX_set_app_data(ctx, NULL);
        }
        return 1;
}

#if !defined(LIBRESSL_VERSION_NUMBER) || LIBRESSL_VERSION_NUMBER <= 0x3040300fL || LIBRESSL_VERSION_NUMBER >= 0x3070100fL
const EVP_CIPHER *evp_ssh1_3des(void)
{
#if !defined(LIBRESSL_VERSION_NUMBER) || LIBRESSL_VERSION_NUMBER >= 0x3070100fL
        static EVP_CIPHER *p = NULL;

        if (p == NULL) {
                p = EVP_CIPHER_meth_new(NID_undef, /*block_size*/8, /*key_len*/16);
                /*** TODO: OPENSSL1.1.1 ERROR CHECK(ticket#39335�����u�\��) ***/
        }
        if (p) {
                EVP_CIPHER_meth_set_iv_length(p, 0);
                EVP_CIPHER_meth_set_init(p, ssh1_3des_init);
                EVP_CIPHER_meth_set_cleanup(p, ssh1_3des_cleanup);
                EVP_CIPHER_meth_set_do_cipher(p, ssh1_3des_cbc);
                EVP_CIPHER_meth_set_flags(p, EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH);
        }
        return (p);
#else
        static EVP_CIPHER ssh1_3des;

        memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
        ssh1_3des.nid = NID_undef;
        ssh1_3des.block_size = 8;
        ssh1_3des.iv_len = 0;
        ssh1_3des.key_len = 16;
        ssh1_3des.init = ssh1_3des_init;
        ssh1_3des.cleanup = ssh1_3des_cleanup;
        ssh1_3des.do_cipher = ssh1_3des_cbc;
        ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
        return (&ssh1_3des);
#endif
}
#endif