Annotation of src/usr.bin/ssh/cipher-3des1.c, Revision 1.7
1.7 ! djm 1: /* $OpenBSD: cipher-3des1.c,v 1.6 2006/08/03 03:34:42 deraadt Exp $ */
1.1 markus 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:
1.6 deraadt 26: #include <sys/types.h>
1.1 markus 27:
28: #include <openssl/evp.h>
1.5 stevesk 29:
30: #include <string.h>
31:
1.1 markus 32: #include "xmalloc.h"
33: #include "log.h"
34:
35: /*
36: * This is used by SSH1:
37: *
38: * What kind of triple DES are these 2 routines?
39: *
40: * Why is there a redundant initialization vector?
41: *
42: * If only iv3 was used, then, this would till effect have been
43: * outer-cbc. However, there is also a private iv1 == iv2 which
44: * perhaps makes differential analysis easier. On the other hand, the
45: * private iv1 probably makes the CRC-32 attack ineffective. This is a
46: * result of that there is no longer any known iv1 to use when
47: * choosing the X block.
48: */
49: struct ssh1_3des_ctx
50: {
51: EVP_CIPHER_CTX k1, k2, k3;
52: };
53:
54: const EVP_CIPHER * evp_ssh1_3des(void);
55: void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
56:
57: static int
58: ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
59: int enc)
60: {
61: struct ssh1_3des_ctx *c;
62: u_char *k1, *k2, *k3;
63:
64: if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
65: c = xmalloc(sizeof(*c));
66: EVP_CIPHER_CTX_set_app_data(ctx, c);
67: }
68: if (key == NULL)
69: return (1);
70: if (enc == -1)
71: enc = ctx->encrypt;
72: k1 = k2 = k3 = (u_char *) key;
73: k2 += 8;
74: if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
75: if (enc)
76: k3 += 16;
77: else
78: k1 += 16;
79: }
80: EVP_CIPHER_CTX_init(&c->k1);
81: EVP_CIPHER_CTX_init(&c->k2);
82: EVP_CIPHER_CTX_init(&c->k3);
83: if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 ||
84: EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 ||
85: EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
86: memset(c, 0, sizeof(*c));
87: xfree(c);
88: EVP_CIPHER_CTX_set_app_data(ctx, NULL);
89: return (0);
90: }
91: return (1);
92: }
93:
94: static int
1.7 ! djm 95: ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, size_t len)
1.1 markus 96: {
97: struct ssh1_3des_ctx *c;
98:
99: if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
100: error("ssh1_3des_cbc: no context");
101: return (0);
102: }
103: if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
104: EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
105: EVP_Cipher(&c->k3, dest, dest, len) == 0)
106: return (0);
107: return (1);
108: }
109:
110: static int
111: ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
112: {
113: struct ssh1_3des_ctx *c;
114:
115: if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
1.2 markus 116: EVP_CIPHER_CTX_cleanup(&c->k1);
117: EVP_CIPHER_CTX_cleanup(&c->k2);
118: EVP_CIPHER_CTX_cleanup(&c->k3);
1.1 markus 119: memset(c, 0, sizeof(*c));
120: xfree(c);
121: EVP_CIPHER_CTX_set_app_data(ctx, NULL);
122: }
123: return (1);
124: }
125:
126: void
127: ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len)
128: {
129: struct ssh1_3des_ctx *c;
130:
131: if (len != 24)
132: fatal("%s: bad 3des iv length: %d", __func__, len);
133: if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
134: fatal("%s: no 3des context", __func__);
135: if (doset) {
136: debug3("%s: Installed 3DES IV", __func__);
137: memcpy(c->k1.iv, iv, 8);
138: memcpy(c->k2.iv, iv + 8, 8);
139: memcpy(c->k3.iv, iv + 16, 8);
140: } else {
141: debug3("%s: Copying 3DES IV", __func__);
142: memcpy(iv, c->k1.iv, 8);
143: memcpy(iv + 8, c->k2.iv, 8);
144: memcpy(iv + 16, c->k3.iv, 8);
145: }
146: }
147:
148: const EVP_CIPHER *
149: evp_ssh1_3des(void)
150: {
151: static EVP_CIPHER ssh1_3des;
152:
153: memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
154: ssh1_3des.nid = NID_undef;
155: ssh1_3des.block_size = 8;
156: ssh1_3des.iv_len = 0;
157: ssh1_3des.key_len = 16;
158: ssh1_3des.init = ssh1_3des_init;
159: ssh1_3des.cleanup = ssh1_3des_cleanup;
160: ssh1_3des.do_cipher = ssh1_3des_cbc;
161: ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
162: return (&ssh1_3des);
163: }