1/* $OpenBSD: cipher-bf1.c,v 1.6 2010/10/01 23:05:32 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 * SSH1 uses a variation on Blowfish, all bytes must be swapped before
42 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
43 */
44
45const EVP_CIPHER * evp_ssh1_bf(void);
46
47static void
48swap_bytes(const u_char *src, u_char *dst, int n)
49{
50	u_char c[4];
51
52	/* Process 4 bytes every lap. */
53	for (n = n / 4; n > 0; n--) {
54		c[3] = *src++;
55		c[2] = *src++;
56		c[1] = *src++;
57		c[0] = *src++;
58
59		*dst++ = c[0];
60		*dst++ = c[1];
61		*dst++ = c[2];
62		*dst++ = c[3];
63	}
64}
65
66#ifdef SSH_OLD_EVP
67static void bf_ssh1_init (EVP_CIPHER_CTX * ctx, const unsigned char *key,
68			  const unsigned char *iv, int enc)
69{
70	if (iv != NULL)
71		memcpy (&(ctx->oiv[0]), iv, 8);
72	memcpy (&(ctx->iv[0]), &(ctx->oiv[0]), 8);
73	if (key != NULL)
74		BF_set_key (&(ctx->c.bf_ks), EVP_CIPHER_CTX_key_length (ctx),
75			    key);
76}
77#endif
78
79static int (*orig_bf)(EVP_CIPHER_CTX *, u_char *,
80    const u_char *, LIBCRYPTO_EVP_INL_TYPE) = NULL;
81
82static int
83bf_ssh1_cipher(EVP_CIPHER_CTX *ctx, u_char *out, const u_char *in,
84    LIBCRYPTO_EVP_INL_TYPE len)
85{
86	int ret;
87
88	swap_bytes(in, out, len);
89	ret = (*orig_bf)(ctx, out, out, len);
90	swap_bytes(out, out, len);
91	return (ret);
92}
93
94const EVP_CIPHER *
95evp_ssh1_bf(void)
96{
97	static EVP_CIPHER ssh1_bf;
98
99	memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));
100	orig_bf = ssh1_bf.do_cipher;
101	ssh1_bf.nid = NID_undef;
102#ifdef SSH_OLD_EVP
103	ssh1_bf.init = bf_ssh1_init;
104#endif
105	ssh1_bf.do_cipher = bf_ssh1_cipher;
106	ssh1_bf.key_len = 32;
107	return (&ssh1_bf);
108}
109