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[OVERVIEW atomicio.c atomicio.h auth-bsdauth.c auth-chall.c auth-krb5.c] [auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c] [auth-rsa.c auth-skey.c auth.c auth.h auth1.c auth2-chall.c auth2-gss.c] [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c ] [auth2-pubkey.c auth2.c authfd.c authfd.h authfile.c bufaux.c bufbn.c] [buffer.c buffer.h canohost.c channels.c channels.h cipher-3des1.c] [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c] [compress.c deattack.c dh.c dispatch.c dns.c dns.h fatal.c groupaccess.c] [groupaccess.h gss-genr.c gss-serv-krb5.c gss-serv.c hostfile.c kex.c] [kex.h kexdh.c kexdhc.c kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c] [key.h log.c log.h mac.c match.c md-sha256.c misc.c misc.h moduli.c] [monitor.c monitor_fdpass.c monitor_mm.c monitor_mm.h monitor_wrap.c] [monitor_wrap.h msg.c nchan.c packet.c progressmeter.c readconf.c] [readconf.h readpass.c rsa.c scard.c scard.h scp.c servconf.c servconf.h] [serverloop.c session.c session.h sftp-client.c sftp-common.c] [sftp-common.h sftp-glob.c sftp-server.c sftp.c ssh-add.c ssh-agent.c] [ssh-dss.c ssh-gss.h ssh-keygen.c ssh-keyscan.c ssh-keysign.c ssh-rsa.c] [ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c] [sshd.c sshlogin.c sshlogin.h sshpty.c sshpty.h sshtty.c ttymodes.c] [uidswap.c uidswap.h uuencode.c uuencode.h xmalloc.c xmalloc.h] [loginrec.c loginrec.h openbsd-compat/port-aix.c openbsd-compat/port-tun.h] almost entirely get rid of the culture of ".h files that include .h files" ok djm, sort of ok stevesk makes the pain stop in one easy step NB. portable commit contains everything *except* removing includes.h, as that will take a fair bit more work as we move headers that are required for portability workarounds to defines.h. (also, this step wasn't "easy")
202 lines
5.8 KiB
C
202 lines
5.8 KiB
C
/* $OpenBSD: kexgexc.c,v 1.9 2006/08/03 03:34:42 deraadt Exp $ */
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/*
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* Copyright (c) 2000 Niels Provos. All rights reserved.
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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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#include <sys/types.h>
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#include <stdio.h>
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#include <string.h>
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#include <signal.h>
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#include "xmalloc.h"
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#include "buffer.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 "packet.h"
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#include "dh.h"
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#include "ssh2.h"
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#include "compat.h"
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void
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kexgex_client(Kex *kex)
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{
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BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
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BIGNUM *p = NULL, *g = NULL;
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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 klen, kout, slen, sbloblen, hashlen;
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int min, max, nbits;
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DH *dh;
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nbits = dh_estimate(kex->we_need * 8);
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if (datafellows & SSH_OLD_DHGEX) {
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/* Old GEX request */
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packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
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packet_put_int(nbits);
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min = DH_GRP_MIN;
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max = DH_GRP_MAX;
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debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD(%u) sent", nbits);
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} else {
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/* New GEX request */
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min = DH_GRP_MIN;
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max = DH_GRP_MAX;
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packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
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packet_put_int(min);
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packet_put_int(nbits);
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packet_put_int(max);
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debug("SSH2_MSG_KEX_DH_GEX_REQUEST(%u<%u<%u) sent",
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min, nbits, max);
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}
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#ifdef DEBUG_KEXDH
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fprintf(stderr, "\nmin = %d, nbits = %d, max = %d\n",
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min, nbits, max);
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#endif
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packet_send();
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debug("expecting SSH2_MSG_KEX_DH_GEX_GROUP");
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packet_read_expect(SSH2_MSG_KEX_DH_GEX_GROUP);
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if ((p = BN_new()) == NULL)
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fatal("BN_new");
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packet_get_bignum2(p);
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if ((g = BN_new()) == NULL)
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fatal("BN_new");
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packet_get_bignum2(g);
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packet_check_eom();
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if (BN_num_bits(p) < min || BN_num_bits(p) > max)
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fatal("DH_GEX group out of range: %d !< %d !< %d",
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min, BN_num_bits(p), max);
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dh = dh_new_group(g, p);
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dh_gen_key(dh, kex->we_need * 8);
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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("SSH2_MSG_KEX_DH_GEX_INIT sent");
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/* generate and send 'e', client DH public key */
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packet_start(SSH2_MSG_KEX_DH_GEX_INIT);
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packet_put_bignum2(dh->pub_key);
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packet_send();
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debug("expecting SSH2_MSG_KEX_DH_GEX_REPLY");
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packet_read_expect(SSH2_MSG_KEX_DH_GEX_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 (server_host_key->type != kex->hostkey_type)
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fatal("type mismatch for decoded server_host_key_blob");
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if (kex->verify_host_key == NULL)
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fatal("cannot verify server_host_key");
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if (kex->verify_host_key(server_host_key) == -1)
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fatal("server_host_key verification failed");
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/* DH parameter f, server public DH key */
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if ((dh_server_pub = BN_new()) == NULL)
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fatal("dh_server_pub == NULL");
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packet_get_bignum2(dh_server_pub);
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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_check_eom();
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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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if ((shared_secret = BN_new()) == NULL)
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fatal("kexgex_client: BN_new failed");
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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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if (datafellows & SSH_OLD_DHGEX)
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min = max = -1;
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/* calc and verify H */
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kexgex_hash(
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kex->evp_md,
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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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min, nbits, max,
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dh->p, dh->g,
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dh->pub_key,
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dh_server_pub,
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shared_secret,
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&hash, &hashlen
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);
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/* have keys, free DH */
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DH_free(dh);
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xfree(server_host_key_blob);
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BN_clear_free(dh_server_pub);
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if (key_verify(server_host_key, signature, slen, hash, hashlen) != 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 = hashlen;
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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, hashlen, shared_secret);
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BN_clear_free(shared_secret);
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kex_finish(kex);
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}
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