1 /* $OpenBSD: cipher-3des1.c,v 1.6 2006/08/03 03:34:42 deraadt Exp $ */
2 /*
3 * Copyright © 2013
4 * Thorsten “mirabilos” Glaser <tg@mirbsd.org>
5 * Copyright (c) 2003 Markus Friedl. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include <sys/types.h>
29
30 #include <openssl/evp.h>
31
32 #include <string.h>
33
34 #include "xmalloc.h"
35 #include "log.h"
36
37 __RCSID("$MirOS: src/usr.bin/ssh/cipher-3des1.c,v 1.5 2013/10/31 20:07:11 tg Exp $");
38
39 /*
40 * This is used by SSH1:
41 *
42 * What kind of triple DES are these 2 routines?
43 *
44 * Why is there a redundant initialization vector?
45 *
46 * If only iv3 was used, then, this would till effect have been
47 * outer-cbc. However, there is also a private iv1 == iv2 which
48 * perhaps makes differential analysis easier. On the other hand, the
49 * private iv1 probably makes the CRC-32 attack ineffective. This is a
50 * result of that there is no longer any known iv1 to use when
51 * choosing the X block.
52 */
53 struct ssh1_3des_ctx
54 {
55 EVP_CIPHER_CTX k1, k2, k3;
56 };
57
58 const EVP_CIPHER * evp_ssh1_3des(void);
59 void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
60
61 static int
ssh1_3des_init(EVP_CIPHER_CTX * ctx,const u_char * key,const u_char * iv,int enc)62 ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key,
63 const u_char *iv __attribute__((__unused__)), int enc)
64 {
65 struct ssh1_3des_ctx *c;
66 u_char *k1, *k2, *k3;
67
68 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
69 c = xmalloc(sizeof(*c));
70 EVP_CIPHER_CTX_set_app_data(ctx, c);
71 }
72 if (key == NULL)
73 return (1);
74 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);
87 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) {
90 memset(c, 0, sizeof(*c));
91 xfree(c);
92 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
93 return (0);
94 }
95 return (1);
96 }
97
98 static int
ssh1_3des_cbc(EVP_CIPHER_CTX * ctx,u_char * dest,const u_char * src,u_int len)99 ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len)
100 {
101 struct ssh1_3des_ctx *c;
102
103 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
104 error("ssh1_3des_cbc: no context");
105 return (0);
106 }
107 if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
108 EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
109 EVP_Cipher(&c->k3, dest, dest, len) == 0)
110 return (0);
111 return (1);
112 }
113
114 static int
ssh1_3des_cleanup(EVP_CIPHER_CTX * ctx)115 ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
116 {
117 struct ssh1_3des_ctx *c;
118
119 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
120 EVP_CIPHER_CTX_cleanup(&c->k1);
121 EVP_CIPHER_CTX_cleanup(&c->k2);
122 EVP_CIPHER_CTX_cleanup(&c->k3);
123 memset(c, 0, sizeof(*c));
124 xfree(c);
125 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
126 }
127 return (1);
128 }
129
130 void
ssh1_3des_iv(EVP_CIPHER_CTX * evp,int doset,u_char * iv,int len)131 ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
132 {
133 struct ssh1_3des_ctx *c;
134
135 if (len != 24)
136 fatal("%s: bad 3des iv length: %d", __func__, len);
137 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
138 fatal("%s: no 3des context", __func__);
139 if (doset) {
140 debug3("%s: Installed 3DES IV", __func__);
141 memcpy(c->k1.iv, iv, 8);
142 memcpy(c->k2.iv, iv + 8, 8);
143 memcpy(c->k3.iv, iv + 16, 8);
144 } else {
145 debug3("%s: Copying 3DES IV", __func__);
146 memcpy(iv, c->k1.iv, 8);
147 memcpy(iv + 8, c->k2.iv, 8);
148 memcpy(iv + 16, c->k3.iv, 8);
149 }
150 }
151
152 const EVP_CIPHER *
evp_ssh1_3des(void)153 evp_ssh1_3des(void)
154 {
155 static EVP_CIPHER ssh1_3des;
156
157 memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
158 ssh1_3des.nid = NID_undef;
159 ssh1_3des.block_size = 8;
160 ssh1_3des.iv_len = 0;
161 ssh1_3des.key_len = 16;
162 ssh1_3des.init = ssh1_3des_init;
163 ssh1_3des.cleanup = ssh1_3des_cleanup;
164 ssh1_3des.do_cipher = ssh1_3des_cbc;
165 ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
166 return (&ssh1_3des);
167 }
168