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Damien Millerd7834352006-08-05 12:39:39 +10001/* $OpenBSD: cipher-3des1.c,v 1.6 2006/08/03 03:34:42 deraadt 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
Damien Millerded319c2006-09-01 15:38:36 +100032#include <stdarg.h>
Damien Millere3476ed2006-07-24 14:13:33 +100033#include <string.h>
34
Damien Miller3a3261f2003-05-15 13:37:19 +100035#include "xmalloc.h"
36#include "log.h"
37
Damien Miller5c3a5582003-09-23 22:12:38 +100038#if OPENSSL_VERSION_NUMBER < 0x00906000L
39#define SSH_OLD_EVP
40#endif
41
Damien Miller3a3261f2003-05-15 13:37:19 +100042/*
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 */
56struct ssh1_3des_ctx
57{
58 EVP_CIPHER_CTX k1, k2, k3;
59};
60
61const EVP_CIPHER * evp_ssh1_3des(void);
62void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
63
64static int
65ssh1_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
107static int
108ssh1_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
129static int
130ssh1_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) {
Darren Tuckera32e19c2003-12-31 11:36:00 +1100135 EVP_CIPHER_CTX_cleanup(&c->k1);
136 EVP_CIPHER_CTX_cleanup(&c->k2);
137 EVP_CIPHER_CTX_cleanup(&c->k3);
Damien Miller3a3261f2003-05-15 13:37:19 +1000138 memset(c, 0, sizeof(*c));
139 xfree(c);
140 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
141 }
142 return (1);
143}
144
145void
146ssh1_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
167const EVP_CIPHER *
168evp_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}