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Damien Miller3ff92ba2014-07-02 15:33:09 +10001/* $OpenBSD: cipher-3des1.c,v 1.11 2014/07/02 04:59:06 djm Exp $ */
Damien Miller3a3261f2003-05-15 13:37:19 +10002/*
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"
Damien Miller3a3261f2003-05-15 13:37:19 +100027
Damien Millerd7834352006-08-05 12:39:39 +100028#include <sys/types.h>
29
Damien Miller3a3261f2003-05-15 13:37:19 +100030#include <openssl/evp.h>
Damien Millere3476ed2006-07-24 14:13:33 +100031
32#include <string.h>
33
Damien Miller3a3261f2003-05-15 13:37:19 +100034#include "xmalloc.h"
35#include "log.h"
Damien Miller86687062014-07-02 15:28:02 +100036#include "ssherr.h"
Damien Miller5c3a5582003-09-23 22:12:38 +100037
Damien Miller3a3261f2003-05-15 13:37:19 +100038/*
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 */
52struct ssh1_3des_ctx
53{
54 EVP_CIPHER_CTX k1, k2, k3;
55};
56
57const EVP_CIPHER * evp_ssh1_3des(void);
Damien Miller86687062014-07-02 15:28:02 +100058int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
Damien Miller3a3261f2003-05-15 13:37:19 +100059
60static int
61ssh1_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) {
Damien Miller86687062014-07-02 15:28:02 +100068 if ((c = calloc(1, sizeof(*c))) == NULL)
69 return 0;
Damien Miller3a3261f2003-05-15 13:37:19 +100070 EVP_CIPHER_CTX_set_app_data(ctx, c);
71 }
72 if (key == NULL)
Damien Miller86687062014-07-02 15:28:02 +100073 return 1;
Damien Miller3a3261f2003-05-15 13:37:19 +100074 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);
Damien Miller3a3261f2003-05-15 13:37:19 +100087 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) {
Damien Millera5103f42014-02-04 11:20:14 +110090 explicit_bzero(c, sizeof(*c));
Darren Tuckera627d422013-06-02 07:31:17 +100091 free(c);
Damien Miller3a3261f2003-05-15 13:37:19 +100092 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
Damien Miller86687062014-07-02 15:28:02 +100093 return 0;
Damien Miller3a3261f2003-05-15 13:37:19 +100094 }
Damien Miller86687062014-07-02 15:28:02 +100095 return 1;
Damien Miller3a3261f2003-05-15 13:37:19 +100096}
97
98static int
Damien Miller86687062014-07-02 15:28:02 +100099ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, size_t len)
Damien Miller3a3261f2003-05-15 13:37:19 +1000100{
101 struct ssh1_3des_ctx *c;
102
Damien Miller86687062014-07-02 15:28:02 +1000103 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL)
104 return 0;
Damien Miller3a3261f2003-05-15 13:37:19 +1000105 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)
Damien Miller86687062014-07-02 15:28:02 +1000108 return 0;
109 return 1;
Damien Miller3a3261f2003-05-15 13:37:19 +1000110}
111
112static int
113ssh1_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) {
Darren Tuckera32e19c2003-12-31 11:36:00 +1100118 EVP_CIPHER_CTX_cleanup(&c->k1);
119 EVP_CIPHER_CTX_cleanup(&c->k2);
120 EVP_CIPHER_CTX_cleanup(&c->k3);
Damien Millera5103f42014-02-04 11:20:14 +1100121 explicit_bzero(c, sizeof(*c));
Darren Tuckera627d422013-06-02 07:31:17 +1000122 free(c);
Damien Miller3a3261f2003-05-15 13:37:19 +1000123 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
124 }
Damien Miller86687062014-07-02 15:28:02 +1000125 return 1;
Damien Miller3a3261f2003-05-15 13:37:19 +1000126}
127
Damien Miller86687062014-07-02 15:28:02 +1000128int
Damien Miller3a3261f2003-05-15 13:37:19 +1000129ssh1_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)
Damien Miller86687062014-07-02 15:28:02 +1000134 return SSH_ERR_INVALID_ARGUMENT;
Damien Miller3a3261f2003-05-15 13:37:19 +1000135 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
Damien Miller86687062014-07-02 15:28:02 +1000136 return SSH_ERR_INTERNAL_ERROR;
Damien Miller3a3261f2003-05-15 13:37:19 +1000137 if (doset) {
Damien Miller3a3261f2003-05-15 13:37:19 +1000138 memcpy(c->k1.iv, iv, 8);
139 memcpy(c->k2.iv, iv + 8, 8);
140 memcpy(c->k3.iv, iv + 16, 8);
141 } else {
Damien Miller3a3261f2003-05-15 13:37:19 +1000142 memcpy(iv, c->k1.iv, 8);
143 memcpy(iv + 8, c->k2.iv, 8);
144 memcpy(iv + 16, c->k3.iv, 8);
145 }
Damien Miller86687062014-07-02 15:28:02 +1000146 return 0;
Damien Miller3a3261f2003-05-15 13:37:19 +1000147}
148
149const EVP_CIPHER *
150evp_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;
Damien Miller3a3261f2003-05-15 13:37:19 +1000162 ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
Damien Miller86687062014-07-02 15:28:02 +1000163 return &ssh1_3des;
Damien Miller3a3261f2003-05-15 13:37:19 +1000164}