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0fff78ff | 1 | /* |
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" | |
26 | RCSID("$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 | */ | |
46 | struct ssh1_3des_ctx | |
47 | { | |
48 | EVP_CIPHER_CTX k1, k2, k3; | |
49 | }; | |
50 | ||
51 | const EVP_CIPHER * evp_ssh1_3des(void); | |
52 | void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); | |
53 | ||
54 | static int | |
55 | ssh1_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 | ||
97 | static int | |
98 | ssh1_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 | ||
119 | static int | |
120 | ssh1_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 | ||
132 | void | |
133 | ssh1_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 | ||
154 | const EVP_CIPHER * | |
155 | evp_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 | } |