1 /* $OpenBSD: cipher-3des1.c,v 1.12 2015/01/14 10:24:42 markus Exp $ */
2 /*
3 * Copyright (c) 2003 Markus Friedl. All rights reserved.
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
10 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
11 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
12 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
13 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
14 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
15 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
16 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
17 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
18 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
19 */
20
21 #include "includes.h"
22
23 #ifdef WITH_SSH1
24
25 #include <sys/types.h>
26 #include <string.h>
27 #include <openssl/evp.h>
28
29 #include "ssherr.h"
30
31 /*
32 * This is used by SSH1:
33 *
34 * What kind of triple DES are these 2 routines?
35 *
36 * Why is there a redundant initialization vector?
37 *
38 * If only iv3 was used, then, this would till effect have been
39 * outer-cbc. However, there is also a private iv1 == iv2 which
40 * perhaps makes differential analysis easier. On the other hand, the
41 * private iv1 probably makes the CRC-32 attack ineffective. This is a
42 * result of that there is no longer any known iv1 to use when
43 * choosing the X block.
44 */
45 struct ssh1_3des_ctx
46 {
47 EVP_CIPHER_CTX k1, k2, k3;
48 };
49
50 const EVP_CIPHER * evp_ssh1_3des(void);
51 int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
52
53 static int
ssh1_3des_init(EVP_CIPHER_CTX * ctx,const u_char * key,const u_char * iv,int enc)54 ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
55 int enc)
56 {
57 struct ssh1_3des_ctx *c;
58 u_char *k1, *k2, *k3;
59
60 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
61 if ((c = calloc(1, sizeof(*c))) == NULL)
62 return 0;
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 if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 ||
81 EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 ||
82 EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
83 explicit_bzero(c, sizeof(*c));
84 free(c);
85 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
86 return 0;
87 }
88 return 1;
89 }
90
91 static int
ssh1_3des_cbc(EVP_CIPHER_CTX * ctx,u_char * dest,const u_char * src,size_t len)92 ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, size_t len)
93 {
94 struct ssh1_3des_ctx *c;
95
96 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL)
97 return 0;
98 if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
99 EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
100 EVP_Cipher(&c->k3, dest, dest, len) == 0)
101 return 0;
102 return 1;
103 }
104
105 static int
ssh1_3des_cleanup(EVP_CIPHER_CTX * ctx)106 ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
107 {
108 struct ssh1_3des_ctx *c;
109
110 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
111 EVP_CIPHER_CTX_cleanup(&c->k1);
112 EVP_CIPHER_CTX_cleanup(&c->k2);
113 EVP_CIPHER_CTX_cleanup(&c->k3);
114 explicit_bzero(c, sizeof(*c));
115 free(c);
116 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
117 }
118 return 1;
119 }
120
121 int
ssh1_3des_iv(EVP_CIPHER_CTX * evp,int doset,u_char * iv,int len)122 ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
123 {
124 struct ssh1_3des_ctx *c;
125
126 if (len != 24)
127 return SSH_ERR_INVALID_ARGUMENT;
128 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
129 return SSH_ERR_INTERNAL_ERROR;
130 if (doset) {
131 memcpy(c->k1.iv, iv, 8);
132 memcpy(c->k2.iv, iv + 8, 8);
133 memcpy(c->k3.iv, iv + 16, 8);
134 } else {
135 memcpy(iv, c->k1.iv, 8);
136 memcpy(iv + 8, c->k2.iv, 8);
137 memcpy(iv + 16, c->k3.iv, 8);
138 }
139 return 0;
140 }
141
142 const EVP_CIPHER *
evp_ssh1_3des(void)143 evp_ssh1_3des(void)
144 {
145 static EVP_CIPHER ssh1_3des;
146
147 memset(&ssh1_3des, 0, sizeof(ssh1_3des));
148 ssh1_3des.nid = NID_undef;
149 ssh1_3des.block_size = 8;
150 ssh1_3des.iv_len = 0;
151 ssh1_3des.key_len = 16;
152 ssh1_3des.init = ssh1_3des_init;
153 ssh1_3des.cleanup = ssh1_3des_cleanup;
154 ssh1_3des.do_cipher = ssh1_3des_cbc;
155 ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
156 return &ssh1_3des;
157 }
158 #endif /* WITH_SSH1 */
159