crypto/openssh/kexgex.c

   1 /* $OpenBSD: kexgex.c,v 1.32 2019/01/23 00:30:41 djm Exp $ */
   2 /*
   3  * Copyright (c) 2000 Niels Provos.  All rights reserved.
   4  * Copyright (c) 2001 Markus Friedl.  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 #ifdef WITH_OPENSSL
  30
  31 #include <sys/types.h>
  32
  33 #include <openssl/evp.h>
  34 #include <signal.h>
  35
  36 #include "openbsd-compat/openssl-compat.h"
  37
  38 #include "sshkey.h"
  39 #include "cipher.h"
  40 #include "kex.h"
  41 #include "ssh2.h"
  42 #include "ssherr.h"
  43 #include "sshbuf.h"
  44 #include "digest.h"
  45
  46 int
  47 kexgex_hash(
  48     int hash_alg,
  49     const struct sshbuf *client_version,
  50     const struct sshbuf *server_version,
  51     const struct sshbuf *client_kexinit,
  52     const struct sshbuf *server_kexinit,
  53     const struct sshbuf *server_host_key_blob,
  54     int min, int wantbits, int max,
  55     const BIGNUM *prime,
  56     const BIGNUM *gen,
  57     const BIGNUM *client_dh_pub,
  58     const BIGNUM *server_dh_pub,
  59     const u_char *shared_secret, size_t secretlen,
  60     u_char *hash, size_t *hashlen)
  61 {
  62         struct sshbuf *b;
  63         int r;
  64
  65         if (*hashlen < ssh_digest_bytes(SSH_DIGEST_SHA1))
  66                 return SSH_ERR_INVALID_ARGUMENT;
  67         if ((b = sshbuf_new()) == NULL)
  68                 return SSH_ERR_ALLOC_FAIL;
  69         if ((r = sshbuf_put_stringb(b, client_version)) < 0 ||
  70             (r = sshbuf_put_stringb(b, server_version)) < 0 ||
  71             /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
  72             (r = sshbuf_put_u32(b, sshbuf_len(client_kexinit) + 1)) != 0 ||
  73             (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
  74             (r = sshbuf_putb(b, client_kexinit)) != 0 ||
  75             (r = sshbuf_put_u32(b, sshbuf_len(server_kexinit) + 1)) != 0 ||
  76             (r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
  77             (r = sshbuf_putb(b, server_kexinit)) != 0 ||
  78             (r = sshbuf_put_stringb(b, server_host_key_blob)) != 0 ||
  79             (min != -1 && (r = sshbuf_put_u32(b, min)) != 0) ||
  80             (r = sshbuf_put_u32(b, wantbits)) != 0 ||
  81             (max != -1 && (r = sshbuf_put_u32(b, max)) != 0) ||
  82             (r = sshbuf_put_bignum2(b, prime)) != 0 ||
  83             (r = sshbuf_put_bignum2(b, gen)) != 0 ||
  84             (r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 ||
  85             (r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 ||
  86             (r = sshbuf_put(b, shared_secret, secretlen)) != 0) {
  87                 sshbuf_free(b);
  88                 return r;
  89         }
  90 #ifdef DEBUG_KEXDH
  91         sshbuf_dump(b, stderr);
  92 #endif
  93         if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
  94                 sshbuf_free(b);
  95                 return SSH_ERR_LIBCRYPTO_ERROR;
  96         }
  97         sshbuf_free(b);
  98         *hashlen = ssh_digest_bytes(hash_alg);
  99 #ifdef DEBUG_KEXDH
 100         dump_digest("hash", hash, *hashlen);
 101 #endif
 102         return 0;
 103 }
 104 #endif /* WITH_OPENSSL */