1 /* $OpenBSD: cipher-bf1.c,v 1.5 2006/08/03 03:34:42 deraadt 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 <sys/types.h>
27
28 #include <openssl/evp.h>
29
30 #include <string.h>
31
32 #include "xmalloc.h"
33 #include "log.h"
34 /*
35 * SSH1 uses a variation on Blowfish, all bytes must be swapped before
36 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
37 */
38
39 const EVP_CIPHER * evp_ssh1_bf(void);
40
41 static void
swap_bytes(const u_char * src,u_char * dst,int n)42 swap_bytes(const u_char *src, u_char *dst, int n)
43 {
44 u_char c[4];
45
46 /* Process 4 bytes every lap. */
47 for (n = n / 4; n > 0; n--) {
48 c[3] = *src++;
49 c[2] = *src++;
50 c[1] = *src++;
51 c[0] = *src++;
52
53 *dst++ = c[0];
54 *dst++ = c[1];
55 *dst++ = c[2];
56 *dst++ = c[3];
57 }
58 }
59
60 static int (*orig_bf)(EVP_CIPHER_CTX *, u_char *, const u_char *, u_int) = NULL;
61
62 static int
bf_ssh1_cipher(EVP_CIPHER_CTX * ctx,u_char * out,const u_char * in,u_int len)63 bf_ssh1_cipher(EVP_CIPHER_CTX *ctx, u_char *out, const u_char *in, u_int len)
64 {
65 int ret;
66
67 swap_bytes(in, out, len);
68 ret = (*orig_bf)(ctx, out, out, len);
69 swap_bytes(out, out, len);
70 return (ret);
71 }
72
73 const EVP_CIPHER *
evp_ssh1_bf(void)74 evp_ssh1_bf(void)
75 {
76 static EVP_CIPHER ssh1_bf;
77
78 memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));
79 orig_bf = ssh1_bf.do_cipher;
80 ssh1_bf.nid = NID_undef;
81 ssh1_bf.do_cipher = bf_ssh1_cipher;
82 ssh1_bf.key_len = 32;
83 return (&ssh1_bf);
84 }
85