1 /* $OpenBSD: cipher-3des1.c,v 1.7 2010/10/01 23:05:32 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 <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
ssh1_3des_init(EVP_CIPHER_CTX * ctx,const u_char * key,const u_char * iv,int enc)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
ssh1_3des_cbc(EVP_CIPHER_CTX * ctx,u_char * dest,const u_char * src,LIBCRYPTO_EVP_INL_TYPE len)106 ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src,
107 LIBCRYPTO_EVP_INL_TYPE len)
108 {
109 struct ssh1_3des_ctx *c;
110
111 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
112 error("ssh1_3des_cbc: no context");
113 return (0);
114 }
115 #ifdef SSH_OLD_EVP
116 EVP_Cipher(&c->k1, dest, (u_char *)src, len);
117 EVP_Cipher(&c->k2, dest, dest, len);
118 EVP_Cipher(&c->k3, dest, dest, len);
119 #else
120 if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
121 EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
122 EVP_Cipher(&c->k3, dest, dest, len) == 0)
123 return (0);
124 #endif
125 return (1);
126 }
127
128 static int
ssh1_3des_cleanup(EVP_CIPHER_CTX * ctx)129 ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
130 {
131 struct ssh1_3des_ctx *c;
132
133 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
134 EVP_CIPHER_CTX_cleanup(&c->k1);
135 EVP_CIPHER_CTX_cleanup(&c->k2);
136 EVP_CIPHER_CTX_cleanup(&c->k3);
137 memset(c, 0, sizeof(*c));
138 xfree(c);
139 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
140 }
141 return (1);
142 }
143
144 void
ssh1_3des_iv(EVP_CIPHER_CTX * evp,int doset,u_char * iv,int len)145 ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
146 {
147 struct ssh1_3des_ctx *c;
148
149 if (len != 24)
150 fatal("%s: bad 3des iv length: %d", __func__, len);
151 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
152 fatal("%s: no 3des context", __func__);
153 if (doset) {
154 debug3("%s: Installed 3DES IV", __func__);
155 memcpy(c->k1.iv, iv, 8);
156 memcpy(c->k2.iv, iv + 8, 8);
157 memcpy(c->k3.iv, iv + 16, 8);
158 } else {
159 debug3("%s: Copying 3DES IV", __func__);
160 memcpy(iv, c->k1.iv, 8);
161 memcpy(iv + 8, c->k2.iv, 8);
162 memcpy(iv + 16, c->k3.iv, 8);
163 }
164 }
165
166 const EVP_CIPHER *
evp_ssh1_3des(void)167 evp_ssh1_3des(void)
168 {
169 static EVP_CIPHER ssh1_3des;
170
171 memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
172 ssh1_3des.nid = NID_undef;
173 ssh1_3des.block_size = 8;
174 ssh1_3des.iv_len = 0;
175 ssh1_3des.key_len = 16;
176 ssh1_3des.init = ssh1_3des_init;
177 ssh1_3des.cleanup = ssh1_3des_cleanup;
178 ssh1_3des.do_cipher = ssh1_3des_cbc;
179 #ifndef SSH_OLD_EVP
180 ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
181 #endif
182 return (&ssh1_3des);
183 }
184