cipher-3des1.c

   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  */
  56 struct ssh1_3des_ctx
  57 {
  58         EVP_CIPHER_CTX  k1, k2, k3;
  59 };
  60
  61 const EVP_CIPHER * evp_ssh1_3des(void);
  62 void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
  63
  64 static int
  65 ssh1_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
 107 static int
 108 ssh1_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
 129 static int
 130 ssh1_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
 145 void
 146 ssh1_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
 167 const EVP_CIPHER *
 168 evp_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 }