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118 lines
3.8 KiB
C
118 lines
3.8 KiB
C
/* $OpenBSD: kexecdh.c,v 1.3 2010/09/22 05:01:29 djm Exp $ */
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/*
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* Copyright (c) 2001 Markus Friedl. All rights reserved.
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* Copyright (c) 2010 Damien Miller. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <signal.h>
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#include <string.h>
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#include <openssl/bn.h>
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#include <openssl/evp.h>
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#include <openssl/ec.h>
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#include <openssl/ecdh.h>
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#include "ssh2.h"
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#include "key.h"
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#include "cipher.h"
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#include "kex.h"
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#include "log.h"
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#include "err.h"
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#include "sshbuf.h"
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int
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kex_ecdh_name_to_nid(const char *kexname)
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{
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if (strlen(kexname) < sizeof(KEX_ECDH_SHA2_STEM) - 1)
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return -1;
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return sshkey_curve_name_to_nid(kexname +
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sizeof(KEX_ECDH_SHA2_STEM) - 1);
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}
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const EVP_MD *
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kex_ecdh_name_to_evpmd(const char *kexname)
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{
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int nid = kex_ecdh_name_to_nid(kexname);
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if (nid == -1)
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return NULL;
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return sshkey_ec_nid_to_evpmd(nid);
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}
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int
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kex_ecdh_hash(
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const EVP_MD *evp_md,
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const EC_GROUP *ec_group,
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char *client_version_string,
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char *server_version_string,
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char *ckexinit, size_t ckexinitlen,
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char *skexinit, size_t skexinitlen,
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u_char *serverhostkeyblob, size_t sbloblen,
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const EC_POINT *client_dh_pub,
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const EC_POINT *server_dh_pub,
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const BIGNUM *shared_secret,
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u_char **hash, size_t *hashlen)
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{
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struct sshbuf *b;
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EVP_MD_CTX md;
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static u_char digest[EVP_MAX_MD_SIZE];
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int r;
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if ((b = sshbuf_new()) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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if ((r = sshbuf_put_cstring(b, client_version_string)) != 0 ||
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(r = sshbuf_put_cstring(b, server_version_string)) != 0 ||
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/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
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(r = sshbuf_put_u32(b, ckexinitlen+1)) != 0 ||
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(r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
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(r = sshbuf_put(b, ckexinit, ckexinitlen)) != 0 ||
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(r = sshbuf_put_u32(b, skexinitlen+1)) != 0 ||
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(r = sshbuf_put_u8(b, SSH2_MSG_KEXINIT)) != 0 ||
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(r = sshbuf_put(b, skexinit, skexinitlen)) != 0 ||
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(r = sshbuf_put_string(b, serverhostkeyblob, sbloblen)) != 0 ||
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(r = sshbuf_put_ec(b, client_dh_pub, ec_group)) != 0 ||
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(r = sshbuf_put_ec(b, server_dh_pub, ec_group)) != 0 ||
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(r = sshbuf_put_bignum2(b, shared_secret)) != 0) {
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sshbuf_free(b);
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return r;
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}
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#ifdef DEBUG_KEX
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sshbuf_dump(b, stderr);
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#endif
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if (EVP_DigestInit(&md, evp_md) != 1 ||
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EVP_DigestUpdate(&md, sshbuf_ptr(b), sshbuf_len(b)) != 1 ||
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EVP_DigestFinal(&md, digest, NULL) != 1) {
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sshbuf_free(b);
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return SSH_ERR_LIBCRYPTO_ERROR;
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}
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sshbuf_free(b);
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#ifdef DEBUG_KEX
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dump_digest("hash", digest, EVP_MD_size(evp_md));
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#endif
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*hash = digest;
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*hashlen = EVP_MD_size(evp_md);
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return 0;
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}
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