cipher-bf1.c revision 124208 
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"
26RCSID("$OpenBSD: cipher-bf1.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#if OPENSSL_VERSION_NUMBER < 0x00906000L
33#define SSH_OLD_EVP
34#endif
35
36/*
37 * SSH1 uses a variation on Blowfish, all bytes must be swapped before
38 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
39 */
40
41const EVP_CIPHER * evp_ssh1_bf(void);
42
43static void
44swap_bytes(const u_char *src, u_char *dst, int n)
45{
46	u_char c[4];
47
48	/* Process 4 bytes every lap. */
49	for (n = n / 4; n > 0; n--) {
50		c[3] = *src++;
51		c[2] = *src++;
52		c[1] = *src++;
53		c[0] = *src++;
54
55		*dst++ = c[0];
56		*dst++ = c[1];
57		*dst++ = c[2];
58		*dst++ = c[3];
59	}
60}
61
62#ifdef SSH_OLD_EVP
63static void bf_ssh1_init (EVP_CIPHER_CTX * ctx, const unsigned char *key,
64			  const unsigned char *iv, int enc)
65{
66	if (iv != NULL)
67		memcpy (&(ctx->oiv[0]), iv, 8);
68	memcpy (&(ctx->iv[0]), &(ctx->oiv[0]), 8);
69	if (key != NULL)
70		BF_set_key (&(ctx->c.bf_ks), EVP_CIPHER_CTX_key_length (ctx),
71			    key);
72}
73#endif
74
75static int (*orig_bf)(EVP_CIPHER_CTX *, u_char *, const u_char *, u_int) = NULL;
76
77static int
78bf_ssh1_cipher(EVP_CIPHER_CTX *ctx, u_char *out, const u_char *in, u_int len)
79{
80	int ret;
81
82	swap_bytes(in, out, len);
83	ret = (*orig_bf)(ctx, out, out, len);
84	swap_bytes(out, out, len);
85	return (ret);
86}
87
88const EVP_CIPHER *
89evp_ssh1_bf(void)
90{
91	static EVP_CIPHER ssh1_bf;
92
93	memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));
94	orig_bf = ssh1_bf.do_cipher;
95	ssh1_bf.nid = NID_undef;
96#ifdef SSH_OLD_EVP
97	ssh1_bf.init = bf_ssh1_init;
98#endif
99	ssh1_bf.do_cipher = bf_ssh1_cipher;
100	ssh1_bf.key_len = 32;
101	return (&ssh1_bf);
102}
103