blob: f9a3523979c53df43daa155f08e22399110c40a1 [file] [log] [blame]
Damien Miller3a3261f2003-05-15 13:37:19 +10001/*
2 * Copyright (c) 2003 Markus Friedl. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
26RCSID("$OpenBSD: cipher-3des1.c,v 1.1 2003/05/15 03:08:29 markus Exp $");
27
28#include <openssl/evp.h>
29#include "xmalloc.h"
30#include "log.h"
31
32/*
33 * This is used by SSH1:
34 *
35 * What kind of triple DES are these 2 routines?
36 *
37 * Why is there a redundant initialization vector?
38 *
39 * If only iv3 was used, then, this would till effect have been
40 * outer-cbc. However, there is also a private iv1 == iv2 which
41 * perhaps makes differential analysis easier. On the other hand, the
42 * private iv1 probably makes the CRC-32 attack ineffective. This is a
43 * result of that there is no longer any known iv1 to use when
44 * choosing the X block.
45 */
46struct ssh1_3des_ctx
47{
48 EVP_CIPHER_CTX k1, k2, k3;
49};
50
51const EVP_CIPHER * evp_ssh1_3des(void);
52void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
53
54static int
55ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
56 int enc)
57{
58 struct ssh1_3des_ctx *c;
59 u_char *k1, *k2, *k3;
60
61 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
62 c = xmalloc(sizeof(*c));
63 EVP_CIPHER_CTX_set_app_data(ctx, c);
64 }
65 if (key == NULL)
66 return (1);
67 if (enc == -1)
68 enc = ctx->encrypt;
69 k1 = k2 = k3 = (u_char *) key;
70 k2 += 8;
71 if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
72 if (enc)
73 k3 += 16;
74 else
75 k1 += 16;
76 }
77 EVP_CIPHER_CTX_init(&c->k1);
78 EVP_CIPHER_CTX_init(&c->k2);
79 EVP_CIPHER_CTX_init(&c->k3);
80#ifdef SSH_OLD_EVP
81 EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc);
82 EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc);
83 EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc);
84#else
85 if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 ||
86 EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 ||
87 EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
88 memset(c, 0, sizeof(*c));
89 xfree(c);
90 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
91 return (0);
92 }
93#endif
94 return (1);
95}
96
97static int
98ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len)
99{
100 struct ssh1_3des_ctx *c;
101
102 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
103 error("ssh1_3des_cbc: no context");
104 return (0);
105 }
106#ifdef SSH_OLD_EVP
107 EVP_Cipher(&c->k1, dest, (u_char *)src, len);
108 EVP_Cipher(&c->k2, dest, dest, len);
109 EVP_Cipher(&c->k3, dest, dest, len);
110#else
111 if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
112 EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
113 EVP_Cipher(&c->k3, dest, dest, len) == 0)
114 return (0);
115#endif
116 return (1);
117}
118
119static int
120ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
121{
122 struct ssh1_3des_ctx *c;
123
124 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
125 memset(c, 0, sizeof(*c));
126 xfree(c);
127 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
128 }
129 return (1);
130}
131
132void
133ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
134{
135 struct ssh1_3des_ctx *c;
136
137 if (len != 24)
138 fatal("%s: bad 3des iv length: %d", __func__, len);
139 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
140 fatal("%s: no 3des context", __func__);
141 if (doset) {
142 debug3("%s: Installed 3DES IV", __func__);
143 memcpy(c->k1.iv, iv, 8);
144 memcpy(c->k2.iv, iv + 8, 8);
145 memcpy(c->k3.iv, iv + 16, 8);
146 } else {
147 debug3("%s: Copying 3DES IV", __func__);
148 memcpy(iv, c->k1.iv, 8);
149 memcpy(iv + 8, c->k2.iv, 8);
150 memcpy(iv + 16, c->k3.iv, 8);
151 }
152}
153
154const EVP_CIPHER *
155evp_ssh1_3des(void)
156{
157 static EVP_CIPHER ssh1_3des;
158
159 memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
160 ssh1_3des.nid = NID_undef;
161 ssh1_3des.block_size = 8;
162 ssh1_3des.iv_len = 0;
163 ssh1_3des.key_len = 16;
164 ssh1_3des.init = ssh1_3des_init;
165 ssh1_3des.cleanup = ssh1_3des_cleanup;
166 ssh1_3des.do_cipher = ssh1_3des_cbc;
167#ifndef SSH_OLD_EVP
168 ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
169#endif
170 return (&ssh1_3des);
171}