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/* $OpenBSD: roaming_client.c,v 1.7 2014/01/09 23:20:00 djm Exp $ */
/*
* Copyright (c) 2004-2009 AppGate Network Security AB
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <inttypes.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <openssl/crypto.h>
#include <openssl/sha.h>
#include "xmalloc.h"
#include "buffer.h"
#include "channels.h"
#include "cipher.h"
#include "dispatch.h"
#include "clientloop.h"
#include "log.h"
#include "match.h"
#include "misc.h"
#include "packet.h"
#include "ssh.h"
#include "key.h"
#include "kex.h"
#include "readconf.h"
#include "roaming.h"
#include "ssh2.h"
#include "sshconnect.h"
#include "digest.h"
/* import */
extern Options options;
extern char *host;
extern struct sockaddr_storage hostaddr;
extern int session_resumed;
static u_int32_t roaming_id;
static u_int64_t cookie;
static u_int64_t lastseenchall;
static u_int64_t key1, key2, oldkey1, oldkey2;
void
roaming_reply(int type, u_int32_t seq, void *ctxt)
{
if (type == SSH2_MSG_REQUEST_FAILURE) {
logit("Server denied roaming");
return;
}
verbose("Roaming enabled");
roaming_id = packet_get_int();
cookie = packet_get_int64();
key1 = oldkey1 = packet_get_int64();
key2 = oldkey2 = packet_get_int64();
set_out_buffer_size(packet_get_int() + get_snd_buf_size());
roaming_enabled = 1;
}
void
request_roaming(void)
{
packet_start(SSH2_MSG_GLOBAL_REQUEST);
packet_put_cstring(ROAMING_REQUEST);
packet_put_char(1);
packet_put_int(get_recv_buf_size());
packet_send();
client_register_global_confirm(roaming_reply, NULL);
}
static void
roaming_auth_required(void)
{
u_char digest[SSH_DIGEST_MAX_LENGTH];
Buffer b;
u_int64_t chall, oldchall;
chall = packet_get_int64();
oldchall = packet_get_int64();
if (oldchall != lastseenchall) {
key1 = oldkey1;
key2 = oldkey2;
}
lastseenchall = chall;
buffer_init(&b);
buffer_put_int64(&b, cookie);
buffer_put_int64(&b, chall);
if (ssh_digest_buffer(SSH_DIGEST_SHA1, &b, digest, sizeof(digest)) != 0)
fatal("%s: ssh_digest_buffer failed", __func__);
buffer_free(&b);
packet_start(SSH2_MSG_KEX_ROAMING_AUTH);
packet_put_int64(key1 ^ get_recv_bytes());
packet_put_raw(digest, ssh_digest_bytes(SSH_DIGEST_SHA1));
packet_send();
oldkey1 = key1;
oldkey2 = key2;
calculate_new_key(&key1, cookie, chall);
calculate_new_key(&key2, cookie, chall);
debug("Received %llu bytes", (unsigned long long)get_recv_bytes());
debug("Sent roaming_auth packet");
}
int
resume_kex(void)
{
/*
* This should not happen - if the client sends the kex method
* resume@appgate.com then the kex is done in roaming_resume().
*/
return 1;
}
static int
roaming_resume(void)
{
u_int64_t recv_bytes;
char *str = NULL, *kexlist = NULL, *c;
int i, type;
int timeout_ms = options.connection_timeout * 1000;
u_int len;
u_int32_t rnd = 0;
resume_in_progress = 1;
/* Exchange banners */
ssh_exchange_identification(timeout_ms);
packet_set_nonblocking();
/* Send a kexinit message with resume@appgate.com as only kex algo */
packet_start(SSH2_MSG_KEXINIT);
for (i = 0; i < KEX_COOKIE_LEN; i++) {
if (i % 4 == 0)
rnd = arc4random();
packet_put_char(rnd & 0xff);
rnd >>= 8;
}
packet_put_cstring(KEX_RESUME);
for (i = 1; i < PROPOSAL_MAX; i++) {
/* kex algorithm added so start with i=1 and not 0 */
packet_put_cstring(""); /* Not used when we resume */
}
packet_put_char(1); /* first kex_packet follows */
packet_put_int(0); /* reserved */
packet_send();
/* Assume that resume@appgate.com will be accepted */
packet_start(SSH2_MSG_KEX_ROAMING_RESUME);
packet_put_int(roaming_id);
packet_send();
/* Read the server's kexinit and check for resume@appgate.com */
if ((type = packet_read()) != SSH2_MSG_KEXINIT) {
debug("expected kexinit on resume, got %d", type);
goto fail;
}
for (i = 0; i < KEX_COOKIE_LEN; i++)
(void)packet_get_char();
kexlist = packet_get_string(&len);
if (!kexlist
|| (str = match_list(KEX_RESUME, kexlist, NULL)) == NULL) {
debug("server doesn't allow resume");
goto fail;
}
free(str);
for (i = 1; i < PROPOSAL_MAX; i++) {
/* kex algorithm taken care of so start with i=1 and not 0 */
free(packet_get_string(&len));
}
i = packet_get_char(); /* first_kex_packet_follows */
if (i && (c = strchr(kexlist, ',')))
*c = 0;
if (i && strcmp(kexlist, KEX_RESUME)) {
debug("server's kex guess (%s) was wrong, skipping", kexlist);
(void)packet_read(); /* Wrong guess - discard packet */
}
/*
* Read the ROAMING_AUTH_REQUIRED challenge from the server and
* send ROAMING_AUTH
*/
if ((type = packet_read()) != SSH2_MSG_KEX_ROAMING_AUTH_REQUIRED) {
debug("expected roaming_auth_required, got %d", type);
goto fail;
}
roaming_auth_required();
/* Read ROAMING_AUTH_OK from the server */
if ((type = packet_read()) != SSH2_MSG_KEX_ROAMING_AUTH_OK) {
debug("expected roaming_auth_ok, got %d", type);
goto fail;
}
recv_bytes = packet_get_int64() ^ oldkey2;
debug("Peer received %llu bytes", (unsigned long long)recv_bytes);
resend_bytes(packet_get_connection_out(), &recv_bytes);
resume_in_progress = 0;
session_resumed = 1; /* Tell clientloop */
return 0;
fail:
free(kexlist);
if (packet_get_connection_in() == packet_get_connection_out())
close(packet_get_connection_in());
else {
close(packet_get_connection_in());
close(packet_get_connection_out());
}
return 1;
}
int
wait_for_roaming_reconnect(void)
{
static int reenter_guard = 0;
int timeout_ms = options.connection_timeout * 1000;
int c;
if (reenter_guard != 0)
fatal("Server refused resume, roaming timeout may be exceeded");
reenter_guard = 1;
fprintf(stderr, "[connection suspended, press return to resume]");
fflush(stderr);
packet_backup_state();
/* TODO Perhaps we should read from tty here */
while ((c = fgetc(stdin)) != EOF) {
if (c == 'Z' - 64) {
kill(getpid(), SIGTSTP);
continue;
}
if (c != '\n' && c != '\r')
continue;
if (ssh_connect(host, NULL, &hostaddr, options.port,
options.address_family, 1, &timeout_ms,
options.tcp_keep_alive, options.use_privileged_port) == 0 &&
roaming_resume() == 0) {
packet_restore_state();
reenter_guard = 0;
fprintf(stderr, "[connection resumed]\n");
fflush(stderr);
return 0;
}
fprintf(stderr, "[reconnect failed, press return to retry]");
fflush(stderr);
}
fprintf(stderr, "[exiting]\n");
fflush(stderr);
exit(0);
}
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