roaming_client.c - security/openssh-library - Rivoreo Source Code Repositories

 /* $OpenBSD: roaming_client.c,v 1.2 2010/01/09 05:17:00 dtucker 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 "includes.h"

 #include "openbsd-compat/sys-queue.h"
 #include <sys/types.h>
 #include <sys/socket.h>

 #ifdef HAVE_INTTYPES_H
 #include <inttypes.h>
 #endif
 #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"

 /* 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[SHA_DIGEST_LENGTH];
 	EVP_MD_CTX md;
 	Buffer b;
 	const EVP_MD *evp_md = EVP_sha1();
 	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);
 	EVP_DigestInit(&md, evp_md);
 	EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
 	EVP_DigestFinal(&md, digest, NULL);
 	buffer_free(&b);

 	packet_start(SSH2_MSG_KEX_ROAMING_AUTH);
 	packet_put_int64(key1 ^ get_recv_bytes());
 	packet_put_raw(digest, sizeof(digest));
 	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;
 	}
 	xfree(str);
 	for (i = 1; i < PROPOSAL_MAX; i++) {
 		/* kex algorithm taken care of so start with i=1 and not 0 */
 		xfree(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:
 	if (kexlist)
 		xfree(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, &hostaddr, options.port,
 		    options.address_family, 1, &timeout_ms,
 		    options.tcp_keep_alive, options.use_privileged_port,
 		    options.proxy_command) == 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);
 }
	/* $OpenBSD: roaming_client.c,v 1.2 2010/01/09 05:17:00 dtucker 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 "includes.h"

	#include "openbsd-compat/sys-queue.h"
	#include <sys/types.h>
	#include <sys/socket.h>

	#ifdef HAVE_INTTYPES_H
	#include <inttypes.h>
	#endif
	#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"

	/* 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[SHA_DIGEST_LENGTH];
	EVP_MD_CTX md;
	Buffer b;
	const EVP_MD *evp_md = EVP_sha1();
	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);
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
	EVP_DigestFinal(&md, digest, NULL);
	buffer_free(&b);

	packet_start(SSH2_MSG_KEX_ROAMING_AUTH);
	packet_put_int64(key1 ^ get_recv_bytes());
	packet_put_raw(digest, sizeof(digest));
	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;
	}
	xfree(str);
	for (i = 1; i < PROPOSAL_MAX; i++) {
	/* kex algorithm taken care of so start with i=1 and not 0 */
	xfree(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:
	if (kexlist)
	xfree(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, &hostaddr, options.port,
	options.address_family, 1, &timeout_ms,
	options.tcp_keep_alive, options.use_privileged_port,
	options.proxy_command) == 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);
	}