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 #include "openbsd-compat/openssl-compat.h"
  39
  40 /*
  41  * This is used by SSH1:
  42  *
  43  * What kind of triple DES are these 2 routines?
  44  *
  45  * Why is there a redundant initialization vector?
  46  *
  47  * If only iv3 was used, then, this would till effect have been
  48  * outer-cbc. However, there is also a private iv1 == iv2 which
  49  * perhaps makes differential analysis easier. On the other hand, the
  50  * private iv1 probably makes the CRC-32 attack ineffective. This is a
  51  * result of that there is no longer any known iv1 to use when
  52  * choosing the X block.
  53  */
  54 struct ssh1_3des_ctx
  55 {
  56         EVP_CIPHER_CTX  k1, k2, k3;
  57 };
  58
  59 const EVP_CIPHER * evp_ssh1_3des(void);
  60 void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
  61
  62 static int
  63 ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
  64     int enc)
  65 {
  66         struct ssh1_3des_ctx *c;
  67         u_char *k1, *k2, *k3;
  68
  69         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
  70                 c = xmalloc(sizeof(*c));
  71                 EVP_CIPHER_CTX_set_app_data(ctx, c);
  72         }
  73         if (key == NULL)
  74                 return (1);
  75         if (enc == -1)
  76                 enc = ctx->encrypt;
  77         k1 = k2 = k3 = (u_char *) key;
  78         k2 += 8;
  79         if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
  80                 if (enc)
  81                         k3 += 16;
  82                 else
  83                         k1 += 16;
  84         }
  85         EVP_CIPHER_CTX_init(&c->k1);
  86         EVP_CIPHER_CTX_init(&c->k2);
  87         EVP_CIPHER_CTX_init(&c->k3);
  88 #ifdef SSH_OLD_EVP
  89         EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc);
  90         EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc);
  91         EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc);
  92 #else
  93         if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 ||
  94             EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 ||
  95             EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
  96                 memset(c, 0, sizeof(*c));
  97                 xfree(c);
  98                 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
  99                 return (0);
 100         }
 101 #endif
 102         return (1);
 103 }
 104
 105 static int
 106 ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len)
 107 {
 108         struct ssh1_3des_ctx *c;
 109
 110         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
 111                 error("ssh1_3des_cbc: no context");
 112                 return (0);
 113         }
 114 #ifdef SSH_OLD_EVP
 115         EVP_Cipher(&c->k1, dest, (u_char *)src, len);
 116         EVP_Cipher(&c->k2, dest, dest, len);
 117         EVP_Cipher(&c->k3, dest, dest, len);
 118 #else
 119         if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
 120             EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
 121             EVP_Cipher(&c->k3, dest, dest, len) == 0)
 122                 return (0);
 123 #endif
 124         return (1);
 125 }
 126
 127 static int
 128 ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
 129 {
 130         struct ssh1_3des_ctx *c;
 131
 132         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
 133                 EVP_CIPHER_CTX_cleanup(&c->k1);
 134                 EVP_CIPHER_CTX_cleanup(&c->k2);
 135                 EVP_CIPHER_CTX_cleanup(&c->k3);
 136                 memset(c, 0, sizeof(*c));
 137                 xfree(c);
 138                 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
 139         }
 140         return (1);
 141 }
 142
 143 void
 144 ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
 145 {
 146         struct ssh1_3des_ctx *c;
 147
 148         if (len != 24)
 149                 fatal("%s: bad 3des iv length: %d", __func__, len);
 150         if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
 151                 fatal("%s: no 3des context", __func__);
 152         if (doset) {
 153                 debug3("%s: Installed 3DES IV", __func__);
 154                 memcpy(c->k1.iv, iv, 8);
 155                 memcpy(c->k2.iv, iv + 8, 8);
 156                 memcpy(c->k3.iv, iv + 16, 8);
 157         } else {
 158                 debug3("%s: Copying 3DES IV", __func__);
 159                 memcpy(iv, c->k1.iv, 8);
 160                 memcpy(iv + 8, c->k2.iv, 8);
 161                 memcpy(iv + 16, c->k3.iv, 8);
 162         }
 163 }
 164
 165 const EVP_CIPHER *
 166 evp_ssh1_3des(void)
 167 {
 168         static EVP_CIPHER ssh1_3des;
 169
 170         memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
 171         ssh1_3des.nid = NID_undef;
 172         ssh1_3des.block_size = 8;
 173         ssh1_3des.iv_len = 0;
 174         ssh1_3des.key_len = 16;
 175         ssh1_3des.init = ssh1_3des_init;
 176         ssh1_3des.cleanup = ssh1_3des_cleanup;
 177         ssh1_3des.do_cipher = ssh1_3des_cbc;
 178 #ifndef SSH_OLD_EVP
 179         ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
 180 #endif
 181         return (&ssh1_3des);
 182 }