1/* $OpenBSD: cipher-3des1.c,v 1.9 2013/11/08 00:39:15 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 */
54struct ssh1_3des_ctx
55{
56	EVP_CIPHER_CTX	k1, k2, k3;
57};
58
59const EVP_CIPHER * evp_ssh1_3des(void);
60void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
61
62static int
63ssh1_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 = xcalloc(1, 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		free(c);
98		EVP_CIPHER_CTX_set_app_data(ctx, NULL);
99		return (0);
100	}
101#endif
102	return (1);
103}
104
105static int
106ssh1_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
128static int
129ssh1_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		free(c);
139		EVP_CIPHER_CTX_set_app_data(ctx, NULL);
140	}
141	return (1);
142}
143
144void
145ssh1_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
166const EVP_CIPHER *
167evp_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