Annotation of src/usr.bin/ssh/cipher-3des1.c, Revision 1.1.6.1
1.1 markus 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"
1.1.6.1 ! brad 26: RCSID("$OpenBSD: cipher-3des1.c,v 1.1 2003/05/15 03:08:29 markus Exp $");
1.1 markus 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: 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: memset(c, 0, sizeof(*c));
84: xfree(c);
85: EVP_CIPHER_CTX_set_app_data(ctx, NULL);
86: return (0);
87: }
88: return (1);
89: }
90:
91: static int
92: ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len)
93: {
94: struct ssh1_3des_ctx *c;
95:
96: if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
97: error("ssh1_3des_cbc: no context");
98: return (0);
99: }
100: if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
101: EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
102: EVP_Cipher(&c->k3, dest, dest, len) == 0)
103: return (0);
104: return (1);
105: }
106:
107: static int
108: ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
109: {
110: struct ssh1_3des_ctx *c;
111:
112: if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
113: memset(c, 0, sizeof(*c));
114: xfree(c);
115: EVP_CIPHER_CTX_set_app_data(ctx, NULL);
116: }
117: return (1);
118: }
119:
120: void
121: ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
122: {
123: struct ssh1_3des_ctx *c;
124:
125: if (len != 24)
126: fatal("%s: bad 3des iv length: %d", __func__, len);
127: if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
128: fatal("%s: no 3des context", __func__);
129: if (doset) {
130: debug3("%s: Installed 3DES IV", __func__);
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: debug3("%s: Copying 3DES IV", __func__);
136: memcpy(iv, c->k1.iv, 8);
137: memcpy(iv + 8, c->k2.iv, 8);
138: memcpy(iv + 16, c->k3.iv, 8);
139: }
140: }
141:
142: const EVP_CIPHER *
143: evp_ssh1_3des(void)
144: {
145: static EVP_CIPHER ssh1_3des;
146:
147: memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
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: }