280 lines
7.1 KiB
C
280 lines
7.1 KiB
C
/* $OpenBSD: roaming_client.c,v 1.5 2013/05/17 00:13:14 djm Exp $ */
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/*
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* Copyright (c) 2004-2009 AppGate Network Security AB
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#include "openbsd-compat/sys-queue.h"
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#include <sys/types.h>
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#include <sys/socket.h>
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#ifdef HAVE_INTTYPES_H
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#include <inttypes.h>
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#endif
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#include <signal.h>
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#include <string.h>
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#include <unistd.h>
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#include <openssl/crypto.h>
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#include <openssl/sha.h>
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#include "xmalloc.h"
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#include "buffer.h"
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#include "channels.h"
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#include "cipher.h"
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#include "dispatch.h"
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#include "clientloop.h"
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#include "log.h"
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#include "match.h"
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#include "misc.h"
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#include "packet.h"
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#include "ssh.h"
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#include "key.h"
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#include "kex.h"
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#include "readconf.h"
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#include "roaming.h"
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#include "ssh2.h"
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#include "sshconnect.h"
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/* import */
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extern Options options;
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extern char *host;
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extern struct sockaddr_storage hostaddr;
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extern int session_resumed;
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static u_int32_t roaming_id;
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static u_int64_t cookie;
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static u_int64_t lastseenchall;
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static u_int64_t key1, key2, oldkey1, oldkey2;
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void
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roaming_reply(int type, u_int32_t seq, void *ctxt)
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{
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if (type == SSH2_MSG_REQUEST_FAILURE) {
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logit("Server denied roaming");
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return;
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}
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verbose("Roaming enabled");
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roaming_id = packet_get_int();
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cookie = packet_get_int64();
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key1 = oldkey1 = packet_get_int64();
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key2 = oldkey2 = packet_get_int64();
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set_out_buffer_size(packet_get_int() + get_snd_buf_size());
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roaming_enabled = 1;
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}
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void
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request_roaming(void)
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{
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packet_start(SSH2_MSG_GLOBAL_REQUEST);
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packet_put_cstring(ROAMING_REQUEST);
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packet_put_char(1);
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packet_put_int(get_recv_buf_size());
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packet_send();
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client_register_global_confirm(roaming_reply, NULL);
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}
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static void
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roaming_auth_required(void)
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{
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u_char digest[SHA_DIGEST_LENGTH];
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EVP_MD_CTX md;
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Buffer b;
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const EVP_MD *evp_md = EVP_sha1();
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u_int64_t chall, oldchall;
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chall = packet_get_int64();
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oldchall = packet_get_int64();
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if (oldchall != lastseenchall) {
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key1 = oldkey1;
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key2 = oldkey2;
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}
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lastseenchall = chall;
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buffer_init(&b);
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buffer_put_int64(&b, cookie);
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buffer_put_int64(&b, chall);
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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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packet_start(SSH2_MSG_KEX_ROAMING_AUTH);
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packet_put_int64(key1 ^ get_recv_bytes());
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packet_put_raw(digest, sizeof(digest));
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packet_send();
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oldkey1 = key1;
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oldkey2 = key2;
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calculate_new_key(&key1, cookie, chall);
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calculate_new_key(&key2, cookie, chall);
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debug("Received %llu bytes", (unsigned long long)get_recv_bytes());
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debug("Sent roaming_auth packet");
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}
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int
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resume_kex(void)
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{
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/*
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* This should not happen - if the client sends the kex method
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* resume@appgate.com then the kex is done in roaming_resume().
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*/
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return 1;
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}
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static int
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roaming_resume(void)
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{
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u_int64_t recv_bytes;
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char *str = NULL, *kexlist = NULL, *c;
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int i, type;
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int timeout_ms = options.connection_timeout * 1000;
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u_int len;
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u_int32_t rnd = 0;
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resume_in_progress = 1;
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/* Exchange banners */
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ssh_exchange_identification(timeout_ms);
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packet_set_nonblocking();
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/* Send a kexinit message with resume@appgate.com as only kex algo */
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packet_start(SSH2_MSG_KEXINIT);
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for (i = 0; i < KEX_COOKIE_LEN; i++) {
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if (i % 4 == 0)
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rnd = arc4random();
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packet_put_char(rnd & 0xff);
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rnd >>= 8;
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}
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packet_put_cstring(KEX_RESUME);
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for (i = 1; i < PROPOSAL_MAX; i++) {
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/* kex algorithm added so start with i=1 and not 0 */
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packet_put_cstring(""); /* Not used when we resume */
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}
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packet_put_char(1); /* first kex_packet follows */
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packet_put_int(0); /* reserved */
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packet_send();
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/* Assume that resume@appgate.com will be accepted */
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packet_start(SSH2_MSG_KEX_ROAMING_RESUME);
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packet_put_int(roaming_id);
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packet_send();
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/* Read the server's kexinit and check for resume@appgate.com */
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if ((type = packet_read()) != SSH2_MSG_KEXINIT) {
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debug("expected kexinit on resume, got %d", type);
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goto fail;
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}
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for (i = 0; i < KEX_COOKIE_LEN; i++)
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(void)packet_get_char();
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kexlist = packet_get_string(&len);
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if (!kexlist
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|| (str = match_list(KEX_RESUME, kexlist, NULL)) == NULL) {
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debug("server doesn't allow resume");
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goto fail;
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}
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free(str);
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for (i = 1; i < PROPOSAL_MAX; i++) {
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/* kex algorithm taken care of so start with i=1 and not 0 */
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free(packet_get_string(&len));
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}
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i = packet_get_char(); /* first_kex_packet_follows */
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if (i && (c = strchr(kexlist, ',')))
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*c = 0;
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if (i && strcmp(kexlist, KEX_RESUME)) {
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debug("server's kex guess (%s) was wrong, skipping", kexlist);
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(void)packet_read(); /* Wrong guess - discard packet */
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}
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/*
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* Read the ROAMING_AUTH_REQUIRED challenge from the server and
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* send ROAMING_AUTH
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*/
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if ((type = packet_read()) != SSH2_MSG_KEX_ROAMING_AUTH_REQUIRED) {
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debug("expected roaming_auth_required, got %d", type);
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goto fail;
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}
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roaming_auth_required();
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/* Read ROAMING_AUTH_OK from the server */
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if ((type = packet_read()) != SSH2_MSG_KEX_ROAMING_AUTH_OK) {
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debug("expected roaming_auth_ok, got %d", type);
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goto fail;
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}
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recv_bytes = packet_get_int64() ^ oldkey2;
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debug("Peer received %llu bytes", (unsigned long long)recv_bytes);
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resend_bytes(packet_get_connection_out(), &recv_bytes);
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resume_in_progress = 0;
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session_resumed = 1; /* Tell clientloop */
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return 0;
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fail:
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free(kexlist);
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if (packet_get_connection_in() == packet_get_connection_out())
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close(packet_get_connection_in());
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else {
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close(packet_get_connection_in());
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close(packet_get_connection_out());
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}
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return 1;
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}
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int
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wait_for_roaming_reconnect(void)
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{
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static int reenter_guard = 0;
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int timeout_ms = options.connection_timeout * 1000;
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int c;
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if (reenter_guard != 0)
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fatal("Server refused resume, roaming timeout may be exceeded");
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reenter_guard = 1;
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fprintf(stderr, "[connection suspended, press return to resume]");
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fflush(stderr);
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packet_backup_state();
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/* TODO Perhaps we should read from tty here */
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while ((c = fgetc(stdin)) != EOF) {
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if (c == 'Z' - 64) {
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kill(getpid(), SIGTSTP);
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continue;
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}
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if (c != '\n' && c != '\r')
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continue;
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if (ssh_connect(host, &hostaddr, options.port,
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options.address_family, 1, &timeout_ms,
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options.tcp_keep_alive, options.use_privileged_port,
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options.proxy_command) == 0 && roaming_resume() == 0) {
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packet_restore_state();
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reenter_guard = 0;
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fprintf(stderr, "[connection resumed]\n");
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fflush(stderr);
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return 0;
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}
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fprintf(stderr, "[reconnect failed, press return to retry]");
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fflush(stderr);
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}
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fprintf(stderr, "[exiting]\n");
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fflush(stderr);
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exit(0);
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}
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