crypto/openssh/cipher-3des1.c

   1 /* $OpenBSD: cipher-3des1.c,v 1.11 2014/07/02 04:59:06 djm 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 <string.h>
  33
  34 #include "xmalloc.h"
  35 #include "log.h"
  36 #include "ssherr.h"
  37
  38 /*
  39  * This is used by SSH1:
  40  *
  41  * What kind of triple DES are these 2 routines?
  42  *
  43  * Why is there a redundant initialization vector?
  44  *
  45  * If only iv3 was used, then, this would till effect have been
  46  * outer-cbc. However, there is also a private iv1 == iv2 which
  47  * perhaps makes differential analysis easier. On the other hand, the
  48  * private iv1 probably makes the CRC-32 attack ineffective. This is a
  49  * result of that there is no longer any known iv1 to use when
  50  * choosing the X block.
  51  */
  52 struct ssh1_3des_ctx
  53 {
  54         EVP_CIPHER_CTX  k1, k2, k3;
  55 };
  56
  57 const EVP_CIPHER * evp_ssh1_3des(void);
  58 int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
  59
  60 static int
  61 ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
  62     int enc)
  63 {
  64         struct ssh1_3des_ctx *c;
  65         u_char *k1, *k2, *k3;
  66
  67         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
  68                 if ((c = calloc(1, sizeof(*c))) == NULL)
  69                         return 0;
  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                 explicit_bzero(c, sizeof(*c));
  91                 free(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, size_t len)
 100 {
 101         struct ssh1_3des_ctx *c;
 102
 103         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL)
 104                 return 0;
 105         if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
 106             EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
 107             EVP_Cipher(&c->k3, dest, dest, len) == 0)
 108                 return 0;
 109         return 1;
 110 }
 111
 112 static int
 113 ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
 114 {
 115         struct ssh1_3des_ctx *c;
 116
 117         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
 118                 EVP_CIPHER_CTX_cleanup(&c->k1);
 119                 EVP_CIPHER_CTX_cleanup(&c->k2);
 120                 EVP_CIPHER_CTX_cleanup(&c->k3);
 121                 explicit_bzero(c, sizeof(*c));
 122                 free(c);
 123                 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
 124         }
 125         return 1;
 126 }
 127
 128 int
 129 ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
 130 {
 131         struct ssh1_3des_ctx *c;
 132
 133         if (len != 24)
 134                 return SSH_ERR_INVALID_ARGUMENT;
 135         if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
 136                 return SSH_ERR_INTERNAL_ERROR;
 137         if (doset) {
 138                 memcpy(c->k1.iv, iv, 8);
 139                 memcpy(c->k2.iv, iv + 8, 8);
 140                 memcpy(c->k3.iv, iv + 16, 8);
 141         } else {
 142                 memcpy(iv, c->k1.iv, 8);
 143                 memcpy(iv + 8, c->k2.iv, 8);
 144                 memcpy(iv + 16, c->k3.iv, 8);
 145         }
 146         return 0;
 147 }
 148
 149 const EVP_CIPHER *
 150 evp_ssh1_3des(void)
 151 {
 152         static EVP_CIPHER ssh1_3des;
 153
 154         memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
 155         ssh1_3des.nid = NID_undef;
 156         ssh1_3des.block_size = 8;
 157         ssh1_3des.iv_len = 0;
 158         ssh1_3des.key_len = 16;
 159         ssh1_3des.init = ssh1_3des_init;
 160         ssh1_3des.cleanup = ssh1_3des_cleanup;
 161         ssh1_3des.do_cipher = ssh1_3des_cbc;
 162         ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
 163         return &ssh1_3des;
 164 }