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- (bal) Oops.. Missed including kexdh.c and kexgex.c in OpenBSD sync.
This commit is contained in:
Ben Lindstrom
parent
f28f634a3a
commit
22b19b43e4
@ -25,6 +25,7 @@
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(1) force rekeying with ~R, or
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(2) if the server requests rekeying.
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works against ssh-2.0.12/2.0.13/2.1.0/2.2.0/2.3.0/2.3.1/2.4.0
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- (bal) Oops.. Missed including kexdh.c and kexgex.c in OpenBSD sync.
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20010403
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- OpenBSD CVS Sync
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@ -4835,4 +4836,4 @@
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- Wrote replacements for strlcpy and mkdtemp
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- Released 1.0pre1
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$Id: ChangeLog,v 1.1053 2001/04/04 02:03:04 mouring Exp $
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$Id: ChangeLog,v 1.1054 2001/04/04 17:39:19 mouring Exp $
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@ -1,4 +1,4 @@
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# $Id: Makefile.in,v 1.164 2001/03/30 00:55:20 djm Exp $
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# $Id: Makefile.in,v 1.165 2001/04/04 17:39:20 mouring Exp $
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prefix=@prefix@
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exec_prefix=@exec_prefix@
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@ -44,7 +44,7 @@ INSTALL_SSH_PRNG_CMDS=@INSTALL_SSH_PRNG_CMDS@
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TARGETS=ssh$(EXEEXT) sshd$(EXEEXT) ssh-add$(EXEEXT) ssh-keygen$(EXEEXT) ssh-keyscan${EXEEXT} ssh-agent$(EXEEXT) scp$(EXEEXT) $(SFTP_PROGS)
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LIBSSH_OBJS=atomicio.o authfd.o authfile.o bufaux.o buffer.o canohost.o channels.o cipher.o cli.o compat.o compress.o crc32.o deattack.o dh.o dispatch.o mac.o hostfile.o key.o kex.o log.o match.o misc.o mpaux.o nchan.o packet.o radix.o rijndael.o entropy.o readpass.o rsa.o ssh-dss.o ssh-rsa.o tildexpand.o ttymodes.o uidswap.o uuencode.o xmalloc.o
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LIBSSH_OBJS=atomicio.o authfd.o authfile.o bufaux.o buffer.o canohost.o channels.o cipher.o cli.o compat.o compress.o crc32.o deattack.o dh.o dispatch.o mac.o hostfile.o key.o kex.o kexdh.o kexgex.o log.o match.o misc.o mpaux.o nchan.o packet.o radix.o rijndael.o entropy.o readpass.o rsa.o ssh-dss.o ssh-rsa.o tildexpand.o ttymodes.o uidswap.o uuencode.o xmalloc.o
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SSHOBJS= ssh.o sshconnect.o sshconnect1.o sshconnect2.o readconf.o clientloop.o
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304
kexdh.c
Normal file
304
kexdh.c
Normal file
@ -0,0 +1,304 @@
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/*
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* Copyright (c) 2001 Markus Friedl. 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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RCSID("$OpenBSD: kexdh.c,v 1.2 2001/04/03 23:32:12 markus Exp $");
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#include <openssl/crypto.h>
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#include <openssl/bn.h>
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#include "xmalloc.h"
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#include "buffer.h"
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#include "bufaux.h"
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#include "key.h"
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#include "kex.h"
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#include "log.h"
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#include "packet.h"
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#include "dh.h"
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#include "ssh2.h"
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u_char *
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kex_dh_hash(
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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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char *serverhostkeyblob, int sbloblen,
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BIGNUM *client_dh_pub,
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BIGNUM *server_dh_pub,
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BIGNUM *shared_secret)
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{
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Buffer b;
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static u_char digest[EVP_MAX_MD_SIZE];
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EVP_MD *evp_md = EVP_sha1();
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EVP_MD_CTX md;
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buffer_init(&b);
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buffer_put_string(&b, client_version_string, strlen(client_version_string));
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buffer_put_string(&b, server_version_string, strlen(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_bignum2(&b, client_dh_pub);
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buffer_put_bignum2(&b, 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->md_size);
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#endif
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return digest;
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}
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/* client */
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void
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kexdh_client(Kex *kex)
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{
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BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
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DH *dh;
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Key *server_host_key;
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char *server_host_key_blob = NULL, *signature = NULL;
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u_char *kbuf, *hash;
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u_int klen, kout, slen, sbloblen;
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int dlen, plen;
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/* generate and send 'e', client DH public key */
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dh = dh_new_group1();
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dh_gen_key(dh, kex->we_need * 8);
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packet_start(SSH2_MSG_KEXDH_INIT);
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packet_put_bignum2(dh->pub_key);
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packet_send();
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debug("sending SSH2_MSG_KEXDH_INIT");
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#ifdef DEBUG_KEXDH
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DHparams_print_fp(stderr, dh);
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fprintf(stderr, "pub= ");
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BN_print_fp(stderr, dh->pub_key);
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fprintf(stderr, "\n");
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#endif
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debug("expecting SSH2_MSG_KEXDH_REPLY");
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packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY);
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/* key, cert */
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server_host_key_blob = packet_get_string(&sbloblen);
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server_host_key = key_from_blob(server_host_key_blob, sbloblen);
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if (server_host_key == NULL)
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fatal("cannot decode server_host_key_blob");
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if (kex->check_host_key == NULL)
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fatal("cannot check server_host_key");
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kex->check_host_key(server_host_key);
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/* DH paramter f, server public DH key */
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dh_server_pub = BN_new();
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if (dh_server_pub == NULL)
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fatal("dh_server_pub == NULL");
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packet_get_bignum2(dh_server_pub, &dlen);
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#ifdef DEBUG_KEXDH
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fprintf(stderr, "dh_server_pub= ");
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BN_print_fp(stderr, dh_server_pub);
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fprintf(stderr, "\n");
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debug("bits %d", BN_num_bits(dh_server_pub));
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#endif
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/* signed H */
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signature = packet_get_string(&slen);
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packet_done();
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if (!dh_pub_is_valid(dh, dh_server_pub))
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packet_disconnect("bad server public DH value");
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klen = DH_size(dh);
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kbuf = xmalloc(klen);
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kout = DH_compute_key(kbuf, dh_server_pub, dh);
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#ifdef DEBUG_KEXDH
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dump_digest("shared secret", kbuf, kout);
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#endif
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shared_secret = BN_new();
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BN_bin2bn(kbuf, kout, shared_secret);
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memset(kbuf, 0, klen);
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xfree(kbuf);
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/* calc and verify H */
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hash = kex_dh_hash(
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kex->client_version_string,
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kex->server_version_string,
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buffer_ptr(&kex->my), buffer_len(&kex->my),
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buffer_ptr(&kex->peer), buffer_len(&kex->peer),
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server_host_key_blob, sbloblen,
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dh->pub_key,
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dh_server_pub,
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shared_secret
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);
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xfree(server_host_key_blob);
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DH_free(dh);
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BN_free(dh_server_pub);
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if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
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fatal("key_verify failed for server_host_key");
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key_free(server_host_key);
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xfree(signature);
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/* save session id */
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if (kex->session_id == NULL) {
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kex->session_id_len = 20;
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kex->session_id = xmalloc(kex->session_id_len);
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memcpy(kex->session_id, hash, kex->session_id_len);
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}
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kex_derive_keys(kex, hash, shared_secret);
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BN_clear_free(shared_secret);
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kex_send_newkeys();
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}
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/* server */
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void
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kexdh_server(Kex *kex)
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{
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BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
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DH *dh;
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Key *server_host_key;
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u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL;
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u_int sbloblen, klen, kout;
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int dlen, slen, plen;
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/* generate server DH public key */
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dh = dh_new_group1();
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dh_gen_key(dh, kex->we_need * 8);
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debug("expecting SSH2_MSG_KEXDH_INIT");
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packet_read_expect(&plen, SSH2_MSG_KEXDH_INIT);
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if (kex->load_host_key == NULL)
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fatal("Cannot load hostkey");
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server_host_key = kex->load_host_key(kex->hostkey_type);
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if (server_host_key == NULL)
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fatal("Unsupported hostkey type %d", kex->hostkey_type);
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/* key, cert */
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dh_client_pub = BN_new();
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if (dh_client_pub == NULL)
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fatal("dh_client_pub == NULL");
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packet_get_bignum2(dh_client_pub, &dlen);
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#ifdef DEBUG_KEXDH
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fprintf(stderr, "dh_client_pub= ");
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BN_print_fp(stderr, dh_client_pub);
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fprintf(stderr, "\n");
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debug("bits %d", BN_num_bits(dh_client_pub));
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#endif
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#ifdef DEBUG_KEXDH
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DHparams_print_fp(stderr, dh);
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fprintf(stderr, "pub= ");
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BN_print_fp(stderr, dh->pub_key);
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fprintf(stderr, "\n");
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#endif
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if (!dh_pub_is_valid(dh, dh_client_pub))
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packet_disconnect("bad client public DH value");
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klen = DH_size(dh);
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kbuf = xmalloc(klen);
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kout = DH_compute_key(kbuf, dh_client_pub, dh);
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#ifdef DEBUG_KEXDH
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dump_digest("shared secret", kbuf, kout);
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#endif
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shared_secret = BN_new();
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BN_bin2bn(kbuf, kout, shared_secret);
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memset(kbuf, 0, klen);
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xfree(kbuf);
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key_to_blob(server_host_key, &server_host_key_blob, &sbloblen);
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/* calc H */
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hash = kex_dh_hash(
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kex->client_version_string,
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kex->server_version_string,
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buffer_ptr(&kex->peer), buffer_len(&kex->peer),
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buffer_ptr(&kex->my), buffer_len(&kex->my),
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(char *)server_host_key_blob, sbloblen,
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dh_client_pub,
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dh->pub_key,
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shared_secret
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);
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BN_free(dh_client_pub);
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/* save session id := H */
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/* XXX hashlen depends on KEX */
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if (kex->session_id == NULL) {
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kex->session_id_len = 20;
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kex->session_id = xmalloc(kex->session_id_len);
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memcpy(kex->session_id, hash, kex->session_id_len);
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}
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/* sign H */
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/* XXX hashlen depends on KEX */
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key_sign(server_host_key, &signature, &slen, hash, 20);
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/* destroy_sensitive_data(); */
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/* send server hostkey, DH pubkey 'f' and singed H */
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packet_start(SSH2_MSG_KEXDH_REPLY);
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packet_put_string((char *)server_host_key_blob, sbloblen);
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packet_put_bignum2(dh->pub_key); /* f */
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packet_put_string((char *)signature, slen);
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packet_send();
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xfree(signature);
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xfree(server_host_key_blob);
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kex_derive_keys(kex, hash, shared_secret);
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BN_clear_free(shared_secret);
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kex_send_newkeys();
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/* have keys, free DH */
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DH_free(dh);
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}
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void
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kexdh(Kex *kex)
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{
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if (kex->server)
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kexdh_server(kex);
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else
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kexdh_client(kex);
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}
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411
kexgex.c
Normal file
411
kexgex.c
Normal file
@ -0,0 +1,411 @@
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/*
|
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* Copyright (c) 2000 Niels Provos. All rights reserved.
|
||||
* 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 "includes.h"
|
||||
RCSID("$OpenBSD: kexgex.c,v 1.2 2001/04/03 23:32:12 markus Exp $");
|
||||
|
||||
#include <openssl/bn.h>
|
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|
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#include "xmalloc.h"
|
||||
#include "buffer.h"
|
||||
#include "bufaux.h"
|
||||
#include "key.h"
|
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#include "kex.h"
|
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#include "log.h"
|
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#include "packet.h"
|
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#include "dh.h"
|
||||
#include "ssh2.h"
|
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#include "compat.h"
|
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|
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u_char *
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kexgex_hash(
|
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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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char *serverhostkeyblob, int sbloblen,
|
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int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
|
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BIGNUM *client_dh_pub,
|
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BIGNUM *server_dh_pub,
|
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BIGNUM *shared_secret)
|
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{
|
||||
Buffer b;
|
||||
static u_char digest[EVP_MAX_MD_SIZE];
|
||||
EVP_MD *evp_md = EVP_sha1();
|
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EVP_MD_CTX md;
|
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|
||||
buffer_init(&b);
|
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buffer_put_string(&b, client_version_string, strlen(client_version_string));
|
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buffer_put_string(&b, server_version_string, strlen(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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if (min == -1 || max == -1)
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buffer_put_int(&b, wantbits);
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||||
else {
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buffer_put_int(&b, min);
|
||||
buffer_put_int(&b, wantbits);
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||||
buffer_put_int(&b, max);
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}
|
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buffer_put_bignum2(&b, prime);
|
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buffer_put_bignum2(&b, gen);
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buffer_put_bignum2(&b, client_dh_pub);
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buffer_put_bignum2(&b, server_dh_pub);
|
||||
buffer_put_bignum2(&b, shared_secret);
|
||||
|
||||
#ifdef DEBUG_KEXDH
|
||||
buffer_dump(&b);
|
||||
#endif
|
||||
EVP_DigestInit(&md, evp_md);
|
||||
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
|
||||
EVP_DigestFinal(&md, digest, NULL);
|
||||
|
||||
buffer_free(&b);
|
||||
|
||||
#ifdef DEBUG_KEXDH
|
||||
dump_digest("hash", digest, evp_md->md_size);
|
||||
#endif
|
||||
return digest;
|
||||
}
|
||||
|
||||
/* client */
|
||||
|
||||
void
|
||||
kexgex_client(Kex *kex)
|
||||
{
|
||||
BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
|
||||
BIGNUM *p = NULL, *g = NULL;
|
||||
Key *server_host_key;
|
||||
u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL;
|
||||
u_int klen, kout, slen, sbloblen;
|
||||
int dlen, plen, min, max, nbits;
|
||||
DH *dh;
|
||||
|
||||
nbits = dh_estimate(kex->we_need * 8);
|
||||
|
||||
if (datafellows & SSH_OLD_DHGEX) {
|
||||
debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD sent");
|
||||
|
||||
/* Old GEX request */
|
||||
packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
|
||||
packet_put_int(nbits);
|
||||
min = DH_GRP_MIN;
|
||||
max = DH_GRP_MAX;
|
||||
} else {
|
||||
debug("SSH2_MSG_KEX_DH_GEX_REQUEST sent");
|
||||
|
||||
/* New GEX request */
|
||||
min = DH_GRP_MIN;
|
||||
max = DH_GRP_MAX;
|
||||
packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
|
||||
packet_put_int(min);
|
||||
packet_put_int(nbits);
|
||||
packet_put_int(max);
|
||||
}
|
||||
#ifdef DEBUG_KEXDH
|
||||
fprintf(stderr, "\nmin = %d, nbits = %d, max = %d\n",
|
||||
min, nbits, max);
|
||||
#endif
|
||||
packet_send();
|
||||
|
||||
debug("expecting SSH2_MSG_KEX_DH_GEX_GROUP");
|
||||
packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP);
|
||||
|
||||
if ((p = BN_new()) == NULL)
|
||||
fatal("BN_new");
|
||||
packet_get_bignum2(p, &dlen);
|
||||
if ((g = BN_new()) == NULL)
|
||||
fatal("BN_new");
|
||||
packet_get_bignum2(g, &dlen);
|
||||
packet_done();
|
||||
|
||||
if (BN_num_bits(p) < min || BN_num_bits(p) > max)
|
||||
fatal("DH_GEX group out of range: %d !< %d !< %d",
|
||||
min, BN_num_bits(p), max);
|
||||
|
||||
dh = dh_new_group(g, p);
|
||||
dh_gen_key(dh, kex->we_need * 8);
|
||||
|
||||
#ifdef DEBUG_KEXDH
|
||||
DHparams_print_fp(stderr, dh);
|
||||
fprintf(stderr, "pub= ");
|
||||
BN_print_fp(stderr, dh->pub_key);
|
||||
fprintf(stderr, "\n");
|
||||
#endif
|
||||
|
||||
debug("SSH2_MSG_KEX_DH_GEX_INIT sent");
|
||||
/* generate and send 'e', client DH public key */
|
||||
packet_start(SSH2_MSG_KEX_DH_GEX_INIT);
|
||||
packet_put_bignum2(dh->pub_key);
|
||||
packet_send();
|
||||
|
||||
debug("expecting SSH2_MSG_KEX_DH_GEX_REPLY");
|
||||
packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY);
|
||||
|
||||
/* key, cert */
|
||||
server_host_key_blob = packet_get_string(&sbloblen);
|
||||
server_host_key = key_from_blob(server_host_key_blob, sbloblen);
|
||||
if (server_host_key == NULL)
|
||||
fatal("cannot decode server_host_key_blob");
|
||||
|
||||
if (kex->check_host_key == NULL)
|
||||
fatal("cannot check server_host_key");
|
||||
kex->check_host_key(server_host_key);
|
||||
|
||||
/* DH paramter f, server public DH key */
|
||||
dh_server_pub = BN_new();
|
||||
if (dh_server_pub == NULL)
|
||||
fatal("dh_server_pub == NULL");
|
||||
packet_get_bignum2(dh_server_pub, &dlen);
|
||||
|
||||
#ifdef DEBUG_KEXDH
|
||||
fprintf(stderr, "dh_server_pub= ");
|
||||
BN_print_fp(stderr, dh_server_pub);
|
||||
fprintf(stderr, "\n");
|
||||
debug("bits %d", BN_num_bits(dh_server_pub));
|
||||
#endif
|
||||
|
||||
/* signed H */
|
||||
signature = packet_get_string(&slen);
|
||||
packet_done();
|
||||
|
||||
if (!dh_pub_is_valid(dh, dh_server_pub))
|
||||
packet_disconnect("bad server public DH value");
|
||||
|
||||
klen = DH_size(dh);
|
||||
kbuf = xmalloc(klen);
|
||||
kout = DH_compute_key(kbuf, dh_server_pub, dh);
|
||||
#ifdef DEBUG_KEXDH
|
||||
dump_digest("shared secret", kbuf, kout);
|
||||
#endif
|
||||
shared_secret = BN_new();
|
||||
BN_bin2bn(kbuf, kout, shared_secret);
|
||||
memset(kbuf, 0, klen);
|
||||
xfree(kbuf);
|
||||
|
||||
if (datafellows & SSH_OLD_DHGEX)
|
||||
min = max = -1;
|
||||
|
||||
/* calc and verify H */
|
||||
hash = kexgex_hash(
|
||||
kex->client_version_string,
|
||||
kex->server_version_string,
|
||||
buffer_ptr(&kex->my), buffer_len(&kex->my),
|
||||
buffer_ptr(&kex->peer), buffer_len(&kex->peer),
|
||||
server_host_key_blob, sbloblen,
|
||||
min, nbits, max,
|
||||
dh->p, dh->g,
|
||||
dh->pub_key,
|
||||
dh_server_pub,
|
||||
shared_secret
|
||||
);
|
||||
xfree(server_host_key_blob);
|
||||
BN_free(dh_server_pub);
|
||||
|
||||
if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
|
||||
fatal("key_verify failed for server_host_key");
|
||||
key_free(server_host_key);
|
||||
xfree(signature);
|
||||
|
||||
/* save session id */
|
||||
if (kex->session_id == NULL) {
|
||||
kex->session_id_len = 20;
|
||||
kex->session_id = xmalloc(kex->session_id_len);
|
||||
memcpy(kex->session_id, hash, kex->session_id_len);
|
||||
}
|
||||
|
||||
kex_derive_keys(kex, hash, shared_secret);
|
||||
BN_clear_free(shared_secret);
|
||||
|
||||
kex_send_newkeys();
|
||||
|
||||
/* have keys, free DH */
|
||||
DH_free(dh);
|
||||
}
|
||||
|
||||
/* server */
|
||||
|
||||
void
|
||||
kexgex_server(Kex *kex)
|
||||
{
|
||||
BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
|
||||
Key *server_host_key;
|
||||
DH *dh = dh;
|
||||
u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL;
|
||||
u_int sbloblen, klen, kout;
|
||||
int min = -1, max = -1, nbits = -1, type, plen, dlen, slen;
|
||||
|
||||
if (kex->load_host_key == NULL)
|
||||
fatal("Cannot load hostkey");
|
||||
server_host_key = kex->load_host_key(kex->hostkey_type);
|
||||
if (server_host_key == NULL)
|
||||
fatal("Unsupported hostkey type %d", kex->hostkey_type);
|
||||
|
||||
type = packet_read(&plen);
|
||||
switch(type){
|
||||
case SSH2_MSG_KEX_DH_GEX_REQUEST:
|
||||
debug("SSH2_MSG_KEX_DH_GEX_REQUEST received");
|
||||
min = packet_get_int();
|
||||
nbits = packet_get_int();
|
||||
max = packet_get_int();
|
||||
min = MAX(DH_GRP_MIN, min);
|
||||
max = MIN(DH_GRP_MAX, max);
|
||||
break;
|
||||
case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD:
|
||||
debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received");
|
||||
nbits = packet_get_int();
|
||||
min = DH_GRP_MIN;
|
||||
max = DH_GRP_MAX;
|
||||
/* unused for old GEX */
|
||||
break;
|
||||
default:
|
||||
fatal("protocol error during kex, no DH_GEX_REQUEST");
|
||||
}
|
||||
packet_done();
|
||||
|
||||
if (max < min || nbits < min || max < nbits)
|
||||
fatal("DH_GEX_REQUEST, bad parameters: %d !< %d !< %d",
|
||||
min, nbits, max);
|
||||
|
||||
dh = choose_dh(min, nbits, max);
|
||||
if (dh == NULL)
|
||||
packet_disconnect("Protocol error: no matching DH grp found");
|
||||
|
||||
debug("SSH2_MSG_KEX_DH_GEX_GROUP sent");
|
||||
packet_start(SSH2_MSG_KEX_DH_GEX_GROUP);
|
||||
packet_put_bignum2(dh->p);
|
||||
packet_put_bignum2(dh->g);
|
||||
packet_send();
|
||||
|
||||
/* flush */
|
||||
packet_write_wait();
|
||||
|
||||
/* Compute our exchange value in parallel with the client */
|
||||
dh_gen_key(dh, kex->we_need * 8);
|
||||
|
||||
debug("expecting SSH2_MSG_KEX_DH_GEX_INIT");
|
||||
packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_INIT);
|
||||
|
||||
/* key, cert */
|
||||
dh_client_pub = BN_new();
|
||||
if (dh_client_pub == NULL)
|
||||
fatal("dh_client_pub == NULL");
|
||||
packet_get_bignum2(dh_client_pub, &dlen);
|
||||
|
||||
#ifdef DEBUG_KEXDH
|
||||
fprintf(stderr, "dh_client_pub= ");
|
||||
BN_print_fp(stderr, dh_client_pub);
|
||||
fprintf(stderr, "\n");
|
||||
debug("bits %d", BN_num_bits(dh_client_pub));
|
||||
#endif
|
||||
|
||||
#ifdef DEBUG_KEXDH
|
||||
DHparams_print_fp(stderr, dh);
|
||||
fprintf(stderr, "pub= ");
|
||||
BN_print_fp(stderr, dh->pub_key);
|
||||
fprintf(stderr, "\n");
|
||||
#endif
|
||||
if (!dh_pub_is_valid(dh, dh_client_pub))
|
||||
packet_disconnect("bad client public DH value");
|
||||
|
||||
klen = DH_size(dh);
|
||||
kbuf = xmalloc(klen);
|
||||
kout = DH_compute_key(kbuf, dh_client_pub, dh);
|
||||
#ifdef DEBUG_KEXDH
|
||||
dump_digest("shared secret", kbuf, kout);
|
||||
#endif
|
||||
shared_secret = BN_new();
|
||||
BN_bin2bn(kbuf, kout, shared_secret);
|
||||
memset(kbuf, 0, klen);
|
||||
xfree(kbuf);
|
||||
|
||||
key_to_blob(server_host_key, &server_host_key_blob, &sbloblen);
|
||||
|
||||
if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD)
|
||||
min = max = -1;
|
||||
|
||||
/* calc H */ /* XXX depends on 'kex' */
|
||||
hash = kexgex_hash(
|
||||
kex->client_version_string,
|
||||
kex->server_version_string,
|
||||
buffer_ptr(&kex->peer), buffer_len(&kex->peer),
|
||||
buffer_ptr(&kex->my), buffer_len(&kex->my),
|
||||
(char *)server_host_key_blob, sbloblen,
|
||||
min, nbits, max,
|
||||
dh->p, dh->g,
|
||||
dh_client_pub,
|
||||
dh->pub_key,
|
||||
shared_secret
|
||||
);
|
||||
BN_free(dh_client_pub);
|
||||
|
||||
/* save session id := H */
|
||||
/* XXX hashlen depends on KEX */
|
||||
if (kex->session_id == NULL) {
|
||||
kex->session_id_len = 20;
|
||||
kex->session_id = xmalloc(kex->session_id_len);
|
||||
memcpy(kex->session_id, hash, kex->session_id_len);
|
||||
}
|
||||
|
||||
/* sign H */
|
||||
/* XXX hashlen depends on KEX */
|
||||
key_sign(server_host_key, &signature, &slen, hash, 20);
|
||||
|
||||
/* destroy_sensitive_data(); */
|
||||
|
||||
/* send server hostkey, DH pubkey 'f' and singed H */
|
||||
debug("SSH2_MSG_KEX_DH_GEX_REPLY sent");
|
||||
packet_start(SSH2_MSG_KEX_DH_GEX_REPLY);
|
||||
packet_put_string((char *)server_host_key_blob, sbloblen);
|
||||
packet_put_bignum2(dh->pub_key); /* f */
|
||||
packet_put_string((char *)signature, slen);
|
||||
packet_send();
|
||||
xfree(signature);
|
||||
xfree(server_host_key_blob);
|
||||
|
||||
kex_derive_keys(kex, hash, shared_secret);
|
||||
BN_clear_free(shared_secret);
|
||||
|
||||
kex_send_newkeys();
|
||||
|
||||
/* have keys, free DH */
|
||||
DH_free(dh);
|
||||
}
|
||||
|
||||
void
|
||||
kexgex(Kex *kex)
|
||||
{
|
||||
if (kex->server)
|
||||
kexgex_server(kex);
|
||||
else
|
||||
kexgex_client(kex);
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user