crypto/dist/ssh/cipher-3des1.c

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