crypto/external/bsd/openssh/dist/kexgex.c

   1 /*      $NetBSD$        */
   2 /* $OpenBSD: kexgex.c,v 1.27 2006/08/03 03:34:42 deraadt Exp $ */
   3 /*
   4  * Copyright (c) 2000 Niels Provos.  All rights reserved.
   5  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "includes.h"
  29 __RCSID("$NetBSD: kexgex.c,v 1.12 2006/09/28 21:22:14 christos Exp $");
  30 #include <sys/types.h>
  31
  32 #include <openssl/evp.h>
  33 #include <signal.h>
  34
  35 #include "buffer.h"
  36 #include "key.h"
  37 #include "cipher.h"
  38 #include "kex.h"
  39 #include "ssh2.h"
  40
  41 void
  42 kexgex_hash(
  43     const EVP_MD *evp_md,
  44     char *client_version_string,
  45     char *server_version_string,
  46     char *ckexinit, int ckexinitlen,
  47     char *skexinit, int skexinitlen,
  48     u_char *serverhostkeyblob, int sbloblen,
  49     int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
  50     BIGNUM *client_dh_pub,
  51     BIGNUM *server_dh_pub,
  52     BIGNUM *shared_secret,
  53     u_char **hash, u_int *hashlen)
  54 {
  55         Buffer b;
  56         static u_char digest[EVP_MAX_MD_SIZE];
  57         EVP_MD_CTX md;
  58
  59         buffer_init(&b);
  60         buffer_put_cstring(&b, client_version_string);
  61         buffer_put_cstring(&b, server_version_string);
  62
  63         /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
  64         buffer_put_int(&b, ckexinitlen+1);
  65         buffer_put_char(&b, SSH2_MSG_KEXINIT);
  66         buffer_append(&b, ckexinit, ckexinitlen);
  67         buffer_put_int(&b, skexinitlen+1);
  68         buffer_put_char(&b, SSH2_MSG_KEXINIT);
  69         buffer_append(&b, skexinit, skexinitlen);
  70
  71         buffer_put_string(&b, serverhostkeyblob, sbloblen);
  72         if (min == -1 || max == -1)
  73                 buffer_put_int(&b, wantbits);
  74         else {
  75                 buffer_put_int(&b, min);
  76                 buffer_put_int(&b, wantbits);
  77                 buffer_put_int(&b, max);
  78         }
  79         buffer_put_bignum2(&b, prime);
  80         buffer_put_bignum2(&b, gen);
  81         buffer_put_bignum2(&b, client_dh_pub);
  82         buffer_put_bignum2(&b, server_dh_pub);
  83         buffer_put_bignum2(&b, shared_secret);
  84
  85 #ifdef DEBUG_KEXDH
  86         buffer_dump(&b);
  87 #endif
  88
  89         EVP_DigestInit(&md, evp_md);
  90         EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
  91         EVP_DigestFinal(&md, digest, NULL);
  92
  93         buffer_free(&b);
  94         *hash = digest;
  95         *hashlen = EVP_MD_size(evp_md);
  96 #ifdef DEBUG_KEXDH
  97         dump_digest("hash", digest, *hashlen);
  98 #endif
  99 }