crypto/openssh/kexdh.c

   1 /* $OpenBSD: kexdh.c,v 1.26 2016/05/02 10:26:04 djm Exp $ */
   2 /*
   3  * Copyright (c) 2001 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 #ifdef WITH_OPENSSL
  29
  30 #include <sys/types.h>
  31
  32 #include <signal.h>
  33
  34 #include <openssl/evp.h>
  35
  36 #include "ssh2.h"
  37 #include "sshkey.h"
  38 #include "cipher.h"
  39 #include "kex.h"
  40 #include "ssherr.h"
  41 #include "sshbuf.h"
  42 #include "digest.h"
  43
  44 int
  45 kex_dh_hash(
  46     int hash_alg,
  47     const char *client_version_string,
  48     const char *server_version_string,
  49     const u_char *ckexinit, size_t ckexinitlen,
  50     const u_char *skexinit, size_t skexinitlen,
  51     const u_char *serverhostkeyblob, size_t sbloblen,
  52     const BIGNUM *client_dh_pub,
  53     const BIGNUM *server_dh_pub,
  54     const BIGNUM *shared_secret,
  55     u_char *hash, size_t *hashlen)
  56 {
  57         struct sshbuf *b;
  58         int r;
  59
  60         if (*hashlen < ssh_digest_bytes(hash_alg))
  61                 return SSH_ERR_INVALID_ARGUMENT;
  62         if ((b = sshbuf_new()) == NULL)
  63                 return SSH_ERR_ALLOC_FAIL;
  64         if ((r = sshbuf_put_cstring(b, client_version_string)) != 0 ||
  65             (r = sshbuf_put_cstring(b, server_version_string)) != 0 ||
  66             /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
  67             (r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 ||
  68             (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
  69             (r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 ||
  70             (r = sshbuf_put_u32(b, skexinitlen+1)) != 0 ||
  71             (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
  72             (r = sshbuf_put(b, skexinit, skexinitlen)) != 0 ||
  73             (r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 ||
  74             (r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 ||
  75             (r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 ||
  76             (r = sshbuf_put_bignum2(b, shared_secret)) != 0) {
  77                 sshbuf_free(b);
  78                 return r;
  79         }
  80 #ifdef DEBUG_KEX
  81         sshbuf_dump(b, stderr);
  82 #endif
  83         if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
  84                 sshbuf_free(b);
  85                 return SSH_ERR_LIBCRYPTO_ERROR;
  86         }
  87         sshbuf_free(b);
  88         *hashlen = ssh_digest_bytes(hash_alg);
  89 #ifdef DEBUG_KEX
  90         dump_digest("hash", hash, *hashlen);
  91 #endif
  92         return 0;
  93 }
  94 #endif /* WITH_OPENSSL */