Files
libopenssh/ssh/kexdh.c
2012-03-04 21:19:20 +01:00

92 lines
3.2 KiB
C

/* $OpenBSD: kexdh.c,v 1.23 2006/08/03 03:34:42 deraadt Exp $ */
/*
* Copyright (c) 2001 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <signal.h>
#include <openssl/evp.h>
#include "buffer.h"
#include "ssh2.h"
#include "key.h"
#include "cipher.h"
#include "kex.h"
#include "err.h"
int
kex_dh_hash(
char *client_version_string,
char *server_version_string,
char *ckexinit, size_t ckexinitlen,
char *skexinit, size_t skexinitlen,
u_char *serverhostkeyblob, size_t sbloblen,
BIGNUM *client_dh_pub,
BIGNUM *server_dh_pub,
BIGNUM *shared_secret,
u_char **hash, size_t *hashlen)
{
struct sshbuf *b;
static u_char digest[EVP_MAX_MD_SIZE];
const EVP_MD *evp_md = EVP_sha1();
EVP_MD_CTX md;
int r;
if ((b = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_put_cstring(b, client_version_string)) != 0 ||
(r = sshbuf_put_cstring(b, server_version_string)) != 0 ||
/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
(r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 ||
(r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
(r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 ||
(r = sshbuf_put_u32(b, skexinitlen+1)) != 0 ||
(r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
(r = sshbuf_put(b, skexinit, skexinitlen)) != 0 ||
(r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 ||
(r = sshbuf_put_bignum2(b, client_dh_pub)) != 0 ||
(r = sshbuf_put_bignum2(b, server_dh_pub)) != 0 ||
(r = sshbuf_put_bignum2(b, shared_secret)) != 0) {
sshbuf_free(b);
return r;
}
#ifdef DEBUG_KEX
sshbuf_dump(b, stderr);
#endif
if (EVP_DigestInit(&md, evp_md) != 1 ||
EVP_DigestUpdate(&md, sshbuf_ptr(b), sshbuf_len(b)) != 1 ||
EVP_DigestFinal(&md, digest, NULL) != 1) {
sshbuf_free(b);
return SSH_ERR_LIBCRYPTO_ERROR;
}
sshbuf_free(b);
*hash = digest;
*hashlen = EVP_MD_size(evp_md);
#ifdef DEBUG_KEX
dump_digest("hash", digest, *hashlen);
#endif
return 0;
}