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d5f62bf280
[kex.c kex.h kexecdh.c kexecdhc.c kexecdhs.c readconf.c readconf.h]
[servconf.c servconf.h ssh_config.5 sshconnect2.c sshd.c sshd_config.5]
add a KexAlgorithms knob to the client and server configuration to allow
selection of which key exchange methods are used by ssh(1) and sshd(8)
and their order of preference.
ok markus@
118 lines
3.6 KiB
C
118 lines
3.6 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 "includes.h"
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#ifdef OPENSSL_HAS_ECC
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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 "buffer.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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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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fatal("%s: kexname too short \"%s\"", __func__, kexname);
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return key_curve_name_to_nid(kexname + 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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fatal("%s: unsupported ECDH curve \"%s\"", __func__, kexname);
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return key_ec_nid_to_evpmd(nid);
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}
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void
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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, int ckexinitlen,
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char *skexinit, int skexinitlen,
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u_char *serverhostkeyblob, int 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, u_int *hashlen)
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{
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Buffer 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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buffer_init(&b);
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buffer_put_cstring(&b, client_version_string);
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buffer_put_cstring(&b, server_version_string);
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/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
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buffer_put_int(&b, ckexinitlen+1);
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buffer_put_char(&b, SSH2_MSG_KEXINIT);
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buffer_append(&b, ckexinit, ckexinitlen);
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buffer_put_int(&b, skexinitlen+1);
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buffer_put_char(&b, SSH2_MSG_KEXINIT);
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buffer_append(&b, skexinit, skexinitlen);
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buffer_put_string(&b, serverhostkeyblob, sbloblen);
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buffer_put_ecpoint(&b, ec_group, client_dh_pub);
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buffer_put_ecpoint(&b, ec_group, server_dh_pub);
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buffer_put_bignum2(&b, shared_secret);
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#ifdef DEBUG_KEX
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buffer_dump(&b);
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#endif
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EVP_DigestInit(&md, evp_md);
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EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
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EVP_DigestFinal(&md, digest, NULL);
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buffer_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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}
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#endif /* OPENSSL_HAS_ECC */
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