176 lines
5.0 KiB
C
176 lines
5.0 KiB
C
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/*
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* Copyright (c) 2003 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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RCSID("$OpenBSD: cipher-3des1.c,v 1.1 2003/05/15 03:08:29 markus Exp $");
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#include <openssl/evp.h>
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#include "xmalloc.h"
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#include "log.h"
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#if OPENSSL_VERSION_NUMBER < 0x00906000L
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#define SSH_OLD_EVP
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#endif
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/*
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* This is used by SSH1:
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*
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* What kind of triple DES are these 2 routines?
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*
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* Why is there a redundant initialization vector?
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*
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* If only iv3 was used, then, this would till effect have been
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* outer-cbc. However, there is also a private iv1 == iv2 which
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* perhaps makes differential analysis easier. On the other hand, the
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* private iv1 probably makes the CRC-32 attack ineffective. This is a
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* result of that there is no longer any known iv1 to use when
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* choosing the X block.
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*/
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struct ssh1_3des_ctx
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{
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EVP_CIPHER_CTX k1, k2, k3;
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};
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const EVP_CIPHER * evp_ssh1_3des(void);
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void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
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static int
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ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
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int enc)
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{
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struct ssh1_3des_ctx *c;
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u_char *k1, *k2, *k3;
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if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
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c = xmalloc(sizeof(*c));
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EVP_CIPHER_CTX_set_app_data(ctx, c);
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}
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if (key == NULL)
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return (1);
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if (enc == -1)
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enc = ctx->encrypt;
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k1 = k2 = k3 = (u_char *) key;
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k2 += 8;
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if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
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if (enc)
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k3 += 16;
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else
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k1 += 16;
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}
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EVP_CIPHER_CTX_init(&c->k1);
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EVP_CIPHER_CTX_init(&c->k2);
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EVP_CIPHER_CTX_init(&c->k3);
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#ifdef SSH_OLD_EVP
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EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc);
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EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc);
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EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc);
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#else
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if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 ||
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EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 ||
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EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
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memset(c, 0, sizeof(*c));
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xfree(c);
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EVP_CIPHER_CTX_set_app_data(ctx, NULL);
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return (0);
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}
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#endif
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return (1);
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}
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static int
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ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len)
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{
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struct ssh1_3des_ctx *c;
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if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
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error("ssh1_3des_cbc: no context");
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return (0);
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}
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#ifdef SSH_OLD_EVP
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EVP_Cipher(&c->k1, dest, (u_char *)src, len);
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EVP_Cipher(&c->k2, dest, dest, len);
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EVP_Cipher(&c->k3, dest, dest, len);
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#else
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if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
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EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
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EVP_Cipher(&c->k3, dest, dest, len) == 0)
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return (0);
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#endif
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return (1);
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}
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static int
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ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
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{
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struct ssh1_3des_ctx *c;
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if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
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memset(c, 0, sizeof(*c));
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xfree(c);
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EVP_CIPHER_CTX_set_app_data(ctx, NULL);
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}
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return (1);
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}
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void
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ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
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{
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struct ssh1_3des_ctx *c;
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if (len != 24)
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fatal("%s: bad 3des iv length: %d", __func__, len);
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if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
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fatal("%s: no 3des context", __func__);
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if (doset) {
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debug3("%s: Installed 3DES IV", __func__);
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memcpy(c->k1.iv, iv, 8);
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memcpy(c->k2.iv, iv + 8, 8);
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memcpy(c->k3.iv, iv + 16, 8);
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} else {
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debug3("%s: Copying 3DES IV", __func__);
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memcpy(iv, c->k1.iv, 8);
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memcpy(iv + 8, c->k2.iv, 8);
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memcpy(iv + 16, c->k3.iv, 8);
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}
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}
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const EVP_CIPHER *
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evp_ssh1_3des(void)
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{
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static EVP_CIPHER ssh1_3des;
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memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
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ssh1_3des.nid = NID_undef;
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ssh1_3des.block_size = 8;
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ssh1_3des.iv_len = 0;
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ssh1_3des.key_len = 16;
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ssh1_3des.init = ssh1_3des_init;
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ssh1_3des.cleanup = ssh1_3des_cleanup;
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ssh1_3des.do_cipher = ssh1_3des_cbc;
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#ifndef SSH_OLD_EVP
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ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
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#endif
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return (&ssh1_3des);
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}
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