crypto/openssh/kexecdh.c

   1 /* $OpenBSD: kexecdh.c,v 1.6 2015/01/19 20:16:15 markus Exp $ */
   2 /*
   3  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
   4  * Copyright (c) 2010 Damien Miller.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC)
  30
  31 #include <sys/types.h>
  32
  33 #include <signal.h>
  34 #include <string.h>
  35
  36 #include <openssl/bn.h>
  37 #include <openssl/evp.h>
  38 #include <openssl/ec.h>
  39 #include <openssl/ecdh.h>
  40
  41 #include "ssh2.h"
  42 #include "sshkey.h"
  43 #include "cipher.h"
  44 #include "kex.h"
  45 #include "sshbuf.h"
  46 #include "digest.h"
  47 #include "ssherr.h"
  48
  49 int
  50 kex_ecdh_hash(
  51     int hash_alg,
  52     const EC_GROUP *ec_group,
  53     const char *client_version_string,
  54     const char *server_version_string,
  55     const u_char *ckexinit, size_t ckexinitlen,
  56     const u_char *skexinit, size_t skexinitlen,
  57     const u_char *serverhostkeyblob, size_t sbloblen,
  58     const EC_POINT *client_dh_pub,
  59     const EC_POINT *server_dh_pub,
  60     const BIGNUM *shared_secret,
  61     u_char *hash, size_t *hashlen)
  62 {
  63         struct sshbuf *b;
  64         int r;
  65
  66         if (*hashlen < ssh_digest_bytes(hash_alg))
  67                 return SSH_ERR_INVALID_ARGUMENT;
  68         if ((b = sshbuf_new()) == NULL)
  69                 return SSH_ERR_ALLOC_FAIL;
  70         if ((r = sshbuf_put_cstring(b, client_version_string)) != 0 ||
  71             (r = sshbuf_put_cstring(b, server_version_string)) != 0 ||
  72             /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
  73             (r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 ||
  74             (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
  75             (r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 ||
  76             (r = sshbuf_put_u32(b, skexinitlen+1)) != 0 ||
  77             (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
  78             (r = sshbuf_put(b, skexinit, skexinitlen)) != 0 ||
  79             (r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 ||
  80             (r = sshbuf_put_ec(b, client_dh_pub, ec_group)) != 0 ||
  81             (r = sshbuf_put_ec(b, server_dh_pub, ec_group)) != 0 ||
  82             (r = sshbuf_put_bignum2(b, shared_secret)) != 0) {
  83                 sshbuf_free(b);
  84                 return r;
  85         }
  86 #ifdef DEBUG_KEX
  87         sshbuf_dump(b, stderr);
  88 #endif
  89         if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
  90                 sshbuf_free(b);
  91                 return SSH_ERR_LIBCRYPTO_ERROR;
  92         }
  93         sshbuf_free(b);
  94         *hashlen = ssh_digest_bytes(hash_alg);
  95 #ifdef DEBUG_KEX
  96         dump_digest("hash", hash, *hashlen);
  97 #endif
  98         return 0;
  99 }
 100 #endif /* defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) */