mirror of git://anongit.mindrot.org/openssh.git
129 lines
4.4 KiB
C
129 lines
4.4 KiB
C
/* $OpenBSD: kexc25519.c,v 1.8 2015/01/19 20:16:15 markus Exp $ */
|
|
/*
|
|
* Copyright (c) 2001, 2013 Markus Friedl. All rights reserved.
|
|
* Copyright (c) 2010 Damien Miller. All rights reserved.
|
|
* Copyright (c) 2013 Aris Adamantiadis. 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 "includes.h"
|
|
|
|
#include <sys/types.h>
|
|
|
|
#include <signal.h>
|
|
#include <string.h>
|
|
|
|
#include <openssl/bn.h>
|
|
#include <openssl/evp.h>
|
|
|
|
#include "sshbuf.h"
|
|
#include "ssh2.h"
|
|
#include "sshkey.h"
|
|
#include "cipher.h"
|
|
#include "kex.h"
|
|
#include "log.h"
|
|
#include "digest.h"
|
|
#include "ssherr.h"
|
|
|
|
extern int crypto_scalarmult_curve25519(u_char a[CURVE25519_SIZE],
|
|
const u_char b[CURVE25519_SIZE], const u_char c[CURVE25519_SIZE])
|
|
__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
|
|
__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)))
|
|
__attribute__((__bounded__(__minbytes__, 3, CURVE25519_SIZE)));
|
|
|
|
void
|
|
kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
|
|
{
|
|
static const u_char basepoint[CURVE25519_SIZE] = {9};
|
|
|
|
arc4random_buf(key, CURVE25519_SIZE);
|
|
crypto_scalarmult_curve25519(pub, key, basepoint);
|
|
}
|
|
|
|
int
|
|
kexc25519_shared_key(const u_char key[CURVE25519_SIZE],
|
|
const u_char pub[CURVE25519_SIZE], struct sshbuf *out)
|
|
{
|
|
u_char shared_key[CURVE25519_SIZE];
|
|
int r;
|
|
|
|
crypto_scalarmult_curve25519(shared_key, key, pub);
|
|
#ifdef DEBUG_KEXECDH
|
|
dump_digest("shared secret", shared_key, CURVE25519_SIZE);
|
|
#endif
|
|
sshbuf_reset(out);
|
|
r = sshbuf_put_bignum2_bytes(out, shared_key, CURVE25519_SIZE);
|
|
explicit_bzero(shared_key, CURVE25519_SIZE);
|
|
return r;
|
|
}
|
|
|
|
int
|
|
kex_c25519_hash(
|
|
int hash_alg,
|
|
const char *client_version_string,
|
|
const char *server_version_string,
|
|
const char *ckexinit, size_t ckexinitlen,
|
|
const char *skexinit, size_t skexinitlen,
|
|
const u_char *serverhostkeyblob, size_t sbloblen,
|
|
const u_char client_dh_pub[CURVE25519_SIZE],
|
|
const u_char server_dh_pub[CURVE25519_SIZE],
|
|
const u_char *shared_secret, size_t secretlen,
|
|
u_char *hash, size_t *hashlen)
|
|
{
|
|
struct sshbuf *b;
|
|
int r;
|
|
|
|
if (*hashlen < ssh_digest_bytes(hash_alg))
|
|
return SSH_ERR_INVALID_ARGUMENT;
|
|
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_string(b, client_dh_pub, CURVE25519_SIZE)) < 0 ||
|
|
(r = sshbuf_put_string(b, server_dh_pub, CURVE25519_SIZE)) < 0 ||
|
|
(r = sshbuf_put(b, shared_secret, secretlen)) < 0) {
|
|
sshbuf_free(b);
|
|
return r;
|
|
}
|
|
#ifdef DEBUG_KEX
|
|
sshbuf_dump(b, stderr);
|
|
#endif
|
|
if (ssh_digest_buffer(hash_alg, b, hash, *hashlen) != 0) {
|
|
sshbuf_free(b);
|
|
return SSH_ERR_LIBCRYPTO_ERROR;
|
|
}
|
|
sshbuf_free(b);
|
|
*hashlen = ssh_digest_bytes(hash_alg);
|
|
#ifdef DEBUG_KEX
|
|
dump_digest("hash", hash, *hashlen);
|
|
#endif
|
|
return 0;
|
|
}
|