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Annotation of src/usr.bin/ssh/cipher-bf1.c, Revision 1.2

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"
                     26:
                     27: #include <openssl/evp.h>
                     28: #include "xmalloc.h"
                     29: #include "log.h"
                     30: /*
                     31:  * SSH1 uses a variation on Blowfish, all bytes must be swapped before
                     32:  * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
                     33:  */
                     34:
                     35: const EVP_CIPHER * evp_ssh1_bf(void);
                     36:
                     37: static void
                     38: swap_bytes(const u_char *src, u_char *dst, int n)
                     39: {
                     40:        u_char c[4];
                     41:
                     42:        /* Process 4 bytes every lap. */
                     43:        for (n = n / 4; n > 0; n--) {
                     44:                c[3] = *src++;
                     45:                c[2] = *src++;
                     46:                c[1] = *src++;
                     47:                c[0] = *src++;
                     48:
                     49:                *dst++ = c[0];
                     50:                *dst++ = c[1];
                     51:                *dst++ = c[2];
                     52:                *dst++ = c[3];
                     53:        }
                     54: }
                     55:
                     56: static int (*orig_bf)(EVP_CIPHER_CTX *, u_char *, const u_char *, u_int) = NULL;
                     57:
                     58: static int
                     59: bf_ssh1_cipher(EVP_CIPHER_CTX *ctx, u_char *out, const u_char *in, u_int len)
                     60: {
                     61:        int ret;
                     62:
                     63:        swap_bytes(in, out, len);
                     64:        ret = (*orig_bf)(ctx, out, out, len);
                     65:        swap_bytes(out, out, len);
                     66:        return (ret);
                     67: }
                     68:
                     69: const EVP_CIPHER *
                     70: evp_ssh1_bf(void)
                     71: {
                     72:        static EVP_CIPHER ssh1_bf;
                     73:
                     74:        memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));
                     75:        orig_bf = ssh1_bf.do_cipher;
                     76:        ssh1_bf.nid = NID_undef;
                     77:        ssh1_bf.do_cipher = bf_ssh1_cipher;
                     78:        ssh1_bf.key_len = 32;
                     79:        return (&ssh1_bf);
                     80: }