cipher-3des1.c revision 181110
1/* $OpenBSD: cipher-3des1.c,v 1.6 2006/08/03 03:34:42 deraadt Exp $ */ 2/* 3 * Copyright (c) 2003 Markus Friedl. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#include "includes.h" 27 28#include <sys/types.h> 29 30#include <openssl/evp.h> 31 32#include <stdarg.h> 33#include <string.h> 34 35#include "xmalloc.h" 36#include "log.h" 37 38#if OPENSSL_VERSION_NUMBER < 0x00906000L 39#define SSH_OLD_EVP 40#endif 41 42/* 43 * This is used by SSH1: 44 * 45 * What kind of triple DES are these 2 routines? 46 * 47 * Why is there a redundant initialization vector? 48 * 49 * If only iv3 was used, then, this would till effect have been 50 * outer-cbc. However, there is also a private iv1 == iv2 which 51 * perhaps makes differential analysis easier. On the other hand, the 52 * private iv1 probably makes the CRC-32 attack ineffective. This is a 53 * result of that there is no longer any known iv1 to use when 54 * choosing the X block. 55 */ 56struct ssh1_3des_ctx 57{ 58 EVP_CIPHER_CTX k1, k2, k3; 59}; 60 61const EVP_CIPHER * evp_ssh1_3des(void); 62void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); 63 64static int 65ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, 66 int enc) 67{ 68 struct ssh1_3des_ctx *c; 69 u_char *k1, *k2, *k3; 70 71 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { 72 c = xmalloc(sizeof(*c)); 73 EVP_CIPHER_CTX_set_app_data(ctx, c); 74 } 75 if (key == NULL) 76 return (1); 77 if (enc == -1) 78 enc = ctx->encrypt; 79 k1 = k2 = k3 = (u_char *) key; 80 k2 += 8; 81 if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) { 82 if (enc) 83 k3 += 16; 84 else 85 k1 += 16; 86 } 87 EVP_CIPHER_CTX_init(&c->k1); 88 EVP_CIPHER_CTX_init(&c->k2); 89 EVP_CIPHER_CTX_init(&c->k3); 90#ifdef SSH_OLD_EVP 91 EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc); 92 EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc); 93 EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc); 94#else 95 if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 || 96 EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 || 97 EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) { 98 memset(c, 0, sizeof(*c)); 99 xfree(c); 100 EVP_CIPHER_CTX_set_app_data(ctx, NULL); 101 return (0); 102 } 103#endif 104 return (1); 105} 106 107static int 108ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len) 109{ 110 struct ssh1_3des_ctx *c; 111 112 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { 113 error("ssh1_3des_cbc: no context"); 114 return (0); 115 } 116#ifdef SSH_OLD_EVP 117 EVP_Cipher(&c->k1, dest, (u_char *)src, len); 118 EVP_Cipher(&c->k2, dest, dest, len); 119 EVP_Cipher(&c->k3, dest, dest, len); 120#else 121 if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 || 122 EVP_Cipher(&c->k2, dest, dest, len) == 0 || 123 EVP_Cipher(&c->k3, dest, dest, len) == 0) 124 return (0); 125#endif 126 return (1); 127} 128 129static int 130ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx) 131{ 132 struct ssh1_3des_ctx *c; 133 134 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) { 135 EVP_CIPHER_CTX_cleanup(&c->k1); 136 EVP_CIPHER_CTX_cleanup(&c->k2); 137 EVP_CIPHER_CTX_cleanup(&c->k3); 138 memset(c, 0, sizeof(*c)); 139 xfree(c); 140 EVP_CIPHER_CTX_set_app_data(ctx, NULL); 141 } 142 return (1); 143} 144 145void 146ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len) 147{ 148 struct ssh1_3des_ctx *c; 149 150 if (len != 24) 151 fatal("%s: bad 3des iv length: %d", __func__, len); 152 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL) 153 fatal("%s: no 3des context", __func__); 154 if (doset) { 155 debug3("%s: Installed 3DES IV", __func__); 156 memcpy(c->k1.iv, iv, 8); 157 memcpy(c->k2.iv, iv + 8, 8); 158 memcpy(c->k3.iv, iv + 16, 8); 159 } else { 160 debug3("%s: Copying 3DES IV", __func__); 161 memcpy(iv, c->k1.iv, 8); 162 memcpy(iv + 8, c->k2.iv, 8); 163 memcpy(iv + 16, c->k3.iv, 8); 164 } 165} 166 167const EVP_CIPHER * 168evp_ssh1_3des(void) 169{ 170 static EVP_CIPHER ssh1_3des; 171 172 memset(&ssh1_3des, 0, sizeof(EVP_CIPHER)); 173 ssh1_3des.nid = NID_undef; 174 ssh1_3des.block_size = 8; 175 ssh1_3des.iv_len = 0; 176 ssh1_3des.key_len = 16; 177 ssh1_3des.init = ssh1_3des_init; 178 ssh1_3des.cleanup = ssh1_3des_cleanup; 179 ssh1_3des.do_cipher = ssh1_3des_cbc; 180#ifndef SSH_OLD_EVP 181 ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH; 182#endif 183 return (&ssh1_3des); 184} 185