clientloop.c

OpenSSL Source code for SFTP, SSH, and many others

		if (compat20 && session_closed && !channel_still_open())
			break;

		rekeying = (xxx_kex != NULL && !xxx_kex->done);

		if (rekeying) {
			debug("rekeying in progress");
		} else {
			/*
			 * Make packets of buffered stdin data, and buffer
			 * them for sending to the server.
			 */
			if (!compat20)
				client_make_packets_from_stdin_data();

			/*
			 * Make packets from buffered channel data, and
			 * enqueue them for sending to the server.
			 */
			if (packet_not_very_much_data_to_write())
				channel_output_poll();

			/*
			 * Check if the window size has changed, and buffer a
			 * message about it to the server if so.
			 */
			client_check_window_change();

			if (quit_pending)
				break;
		}
		/*
		 * Wait until we have something to do (something becomes
		 * available on one of the descriptors).
		 */
		max_fd2 = max_fd;
		client_wait_until_can_do_something(&readset, &writeset,
		    &max_fd2, &nalloc, rekeying);

		if (quit_pending)
			break;

		/* Do channel operations unless rekeying in progress. */
		if (!rekeying) {
			channel_after_select(readset, writeset);

			if (need_rekeying) {
				debug("user requests rekeying");
				xxx_kex->done = 0;
				kex_send_kexinit(xxx_kex);
				need_rekeying = 0;
			}
		}

		/* Buffer input from the connection.  */
		client_process_net_input(readset);

		if (quit_pending)
			break;

		if (!compat20) {
			/* Buffer data from stdin */
			client_process_input(readset);
			/*
			 * Process output to stdout and stderr.  Output to
			 * the connection is processed elsewhere (above).
			 */
			client_process_output(writeset);
		}

		/* Send as much buffered packet data as possible to the sender. */
		if (FD_ISSET(connection_out, writeset))
			packet_write_poll();
	}
	if (readset)
		xfree(readset);
	if (writeset)
		xfree(writeset);

	/* Terminate the session. */

	/* Stop watching for window change. */
	if (have_pty)
		signal(SIGWINCH, SIG_DFL);

	channel_free_all();

	if (have_pty)
		leave_raw_mode();

	/* restore blocking io */
	if (!isatty(fileno(stdin)))
		unset_nonblock(fileno(stdin));
	if (!isatty(fileno(stdout)))
		unset_nonblock(fileno(stdout));
	if (!isatty(fileno(stderr)))
		unset_nonblock(fileno(stderr));

	if (received_signal) {
		if (in_non_blocking_mode)	/* XXX */
			leave_non_blocking();
		fatal("Killed by signal %d.", (int) received_signal);
	}

	/*
	 * In interactive mode (with pseudo tty) display a message indicating
	 * that the connection has been closed.
	 */
	if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
		snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
		buffer_append(&stderr_buffer, buf, strlen(buf));
	}

	/* Output any buffered data for stdout. */
	while (buffer_len(&stdout_buffer) > 0) {
		len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
		    buffer_len(&stdout_buffer));
		if (len <= 0) {
			error("Write failed flushing stdout buffer.");
			break;
		}
		buffer_consume(&stdout_buffer, len);
		stdout_bytes += len;
	}

	/* Output any buffered data for stderr. */
	while (buffer_len(&stderr_buffer) > 0) {
		len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
		    buffer_len(&stderr_buffer));
		if (len <= 0) {
			error("Write failed flushing stderr buffer.");
			break;
		}
		buffer_consume(&stderr_buffer, len);
		stderr_bytes += len;
	}

	/* Clear and free any buffers. */
	memset(buf, 0, sizeof(buf));
	buffer_free(&stdin_buffer);
	buffer_free(&stdout_buffer);
	buffer_free(&stderr_buffer);

	/* Report bytes transferred, and transfer rates. */
	total_time = get_current_time() - start_time;
	debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
	    stdin_bytes, stdout_bytes, stderr_bytes, total_time);
	if (total_time > 0)
		debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
		    stdin_bytes / total_time, stdout_bytes / total_time,
		    stderr_bytes / total_time);

	/* Return the exit status of the program. */
	debug("Exit status %d", exit_status);
	return exit_status;
}

/*********/

static void
client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
{
	u_int data_len;
	char *data = packet_get_string(&data_len);
	packet_check_eom();
	buffer_append(&stdout_buffer, data, data_len);
	memset(data, 0, data_len);
	xfree(data);
}
static void
client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
{
	u_int data_len;
	char *data = packet_get_string(&data_len);
	packet_check_eom();
	buffer_append(&stderr_buffer, data, data_len);
	memset(data, 0, data_len);
	xfree(data);
}
static void
client_input_exit_status(int type, u_int32_t seq, void *ctxt)
{
	exit_status = packet_get_int();
	packet_check_eom();
	/* Acknowledge the exit. */
	packet_start(SSH_CMSG_EXIT_CONFIRMATION);
	packet_send();
	/*
	 * Must wait for packet to be sent since we are
	 * exiting the loop.
	 */
	packet_write_wait();
	/* Flag that we want to exit. */
	quit_pending = 1;
}

static Channel *
client_request_forwarded_tcpip(const char *request_type, int rchan)
{
	Channel* c = NULL;
	char *listen_address, *originator_address;
	int listen_port, originator_port;
	int sock;

	/* Get rest of the packet */
	listen_address = packet_get_string(NULL);
	listen_port = packet_get_int();
	originator_address = packet_get_string(NULL);
	originator_port = packet_get_int();
	packet_check_eom();

	debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
	    listen_address, listen_port, originator_address, originator_port);

	sock = channel_connect_by_listen_address(listen_port);
	if (sock < 0) {
		xfree(originator_address);
		xfree(listen_address);
		return NULL;
	}
	c = channel_new("forwarded-tcpip",
	    SSH_CHANNEL_CONNECTING, sock, sock, -1,
	    CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
	    xstrdup(originator_address), 1);
	xfree(originator_address);
	xfree(listen_address);
	return c;
}

static Channel*
client_request_x11(const char *request_type, int rchan)
{
	Channel *c = NULL;
	char *originator;
	int originator_port;
	int sock;

	if (!options.forward_x11) {
		error("Warning: ssh server tried X11 forwarding.");
		error("Warning: this is probably a break in attempt by a malicious server.");
		return NULL;
	}
	originator = packet_get_string(NULL);
	if (datafellows & SSH_BUG_X11FWD) {
		debug2("buggy server: x11 request w/o originator_port");
		originator_port = 0;
	} else {
		originator_port = packet_get_int();
	}
	packet_check_eom();
	/* XXX check permission */
	debug("client_request_x11: request from %s %d", originator,
	    originator_port);
	xfree(originator);
	sock = x11_connect_display();
	if (sock < 0)
		return NULL;
	c = channel_new("x11",
	    SSH_CHANNEL_X11_OPEN, sock, sock, -1,
	    CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0,
	    xstrdup("x11"), 1);
	c->force_drain = 1;
	return c;
}

static Channel*
client_request_agent(const char *request_type, int rchan)
{
	Channel *c = NULL;
	int sock;

	if (!options.forward_agent) {
		error("Warning: ssh server tried agent forwarding.");
		error("Warning: this is probably a break in attempt by a malicious server.");
		return NULL;
	}
	sock =  ssh_get_authentication_socket();
	if (sock < 0)
		return NULL;
	c = channel_new("authentication agent connection",
	    SSH_CHANNEL_OPEN, sock, sock, -1,
	    CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
	    xstrdup("authentication agent connection"), 1);
	c->force_drain = 1;
	return c;
}

/* XXXX move to generic input handler */
static void
client_input_channel_open(int type, u_int32_t seq, void *ctxt)
{
	Channel *c = NULL;
	char *ctype;
	u_int len;
	int rchan;
	int rmaxpack;
	int rwindow;

	ctype = packet_get_string(&len);
	rchan = packet_get_int();
	rwindow = packet_get_int();
	rmaxpack = packet_get_int();

	debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
	    ctype, rchan, rwindow, rmaxpack);

	if (strcmp(ctype, "forwarded-tcpip") == 0) {
		c = client_request_forwarded_tcpip(ctype, rchan);
	} else if (strcmp(ctype, "x11") == 0) {
		c = client_request_x11(ctype, rchan);
	} else if (strcmp(ctype, "[e-mail]") == 0) {
		c = client_request_agent(ctype, rchan);
	}
/* XXX duplicate : */
	if (c != NULL) {
		debug("confirm %s", ctype);
		c->remote_id = rchan;
		c->remote_window = rwindow;
		c->remote_maxpacket = rmaxpack;
		if (c->type != SSH_CHANNEL_CONNECTING) {
			packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
			packet_put_int(c->remote_id);
			packet_put_int(c->self);
			packet_put_int(c->local_window);
			packet_put_int(c->local_maxpacket);
			packet_send();
		}
	} else {
		debug("failure %s", ctype);
		packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
		packet_put_int(rchan);
		packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
		if (!(datafellows & SSH_BUG_OPENFAILURE)) {
			packet_put_cstring("open failed");
			packet_put_cstring("");
		}
		packet_send();
	}
	xfree(ctype);
}
static void
client_input_channel_req(int type, u_int32_t seq, void *ctxt)
{
	Channel *c = NULL;
	int id, reply, success = 0;
	char *rtype;

	id = packet_get_int();
	rtype = packet_get_string(NULL);
	reply = packet_get_char();

	debug("client_input_channel_req: channel %d rtype %s reply %d",
	    id, rtype, reply);

	if (session_ident == -1) {
		error("client_input_channel_req: no channel %d", session_ident);
	} else if (id != session_ident) {
		error("client_input_channel_req: channel %d: wrong channel: %d",
		    session_ident, id);
	}
	c = channel_lookup(id);
	if (c == NULL) {
		error("client_input_channel_req: channel %d: unknown channel", id);
	} else if (strcmp(rtype, "exit-status") == 0) {
		success = 1;
		exit_status = packet_get_int();
		packet_check_eom();
	}
	if (reply) {
		packet_start(success ?
		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
		packet_put_int(c->remote_id);
		packet_send();
	}
	xfree(rtype);
}
static void
client_input_global_request(int type, u_int32_t seq, void *ctxt)
{
	char *rtype;
	int want_reply;
	int success = 0;

	rtype = packet_get_string(NULL);
	want_reply = packet_get_char();
	debug("client_input_global_request: rtype %s want_reply %d", rtype, want_reply);
	if (want_reply) {
		packet_start(success ?
		    SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
		packet_send();
		packet_write_wait();
	}
	xfree(rtype);
}

static void
client_init_dispatch_20(void)
{
	dispatch_init(&dispatch_protocol_error);

	dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
	dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
	dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
	dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
	dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
	dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
	dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
	dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);

	/* rekeying */
	dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);

	/* global request reply messages */
	dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
	dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
}
static void
client_init_dispatch_13(void)
{
	dispatch_init(NULL);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
	dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
	dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
	dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
	dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
	dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
	dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
	dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);

	dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
	    &auth_input_open_request : &deny_input_open);
	dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
	    &x11_input_open : &deny_input_open);
}
static void
client_init_dispatch_15(void)
{
	client_init_dispatch_13();
	dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
	dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
}
static void
client_init_dispatch(void)
{
	if (compat20)
		client_init_dispatch_20();
	else if (compat13)
		client_init_dispatch_13();
	else
		client_init_dispatch_15();
}