2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 RCSID("$OpenBSD: channels.c,v 1.85 2001/01/29 19:42:35 markus Exp $");
45 #include <openssl/rsa.h>
46 #include <openssl/dsa.h>
64 /* Maximum number of fake X11 displays to try. */
65 #define MAX_DISPLAYS 1000
67 /* Max len of agent socket */
68 #define MAX_SOCKET_NAME 100
71 * Pointer to an array containing all allocated channels. The array is
72 * dynamically extended as needed.
74 static Channel *channels = NULL;
77 * Size of the channel array. All slots of the array must always be
78 * initialized (at least the type field); unused slots are marked with type
81 static int channels_alloc = 0;
84 * Maximum file descriptor value used in any of the channels. This is
85 * updated in channel_allocate.
87 static int channel_max_fd = 0;
89 /* Name and directory of socket for authentication agent forwarding. */
90 static char *channel_forwarded_auth_socket_name = NULL;
91 static char *channel_forwarded_auth_socket_dir = NULL;
93 /* Saved X11 authentication protocol name. */
94 char *x11_saved_proto = NULL;
96 /* Saved X11 authentication data. This is the real data. */
97 char *x11_saved_data = NULL;
98 u_int x11_saved_data_len = 0;
101 * Fake X11 authentication data. This is what the server will be sending us;
102 * we should replace any occurrences of this by the real data.
104 char *x11_fake_data = NULL;
105 u_int x11_fake_data_len;
108 * Data structure for storing which hosts are permitted for forward requests.
109 * The local sides of any remote forwards are stored in this array to prevent
110 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
111 * network (which might be behind a firewall).
114 char *host_to_connect; /* Connect to 'host'. */
115 u_short port_to_connect; /* Connect to 'port'. */
116 u_short listen_port; /* Remote side should listen port number. */
119 /* List of all permitted host/port pairs to connect. */
120 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
121 /* Number of permitted host/port pairs in the array. */
122 static int num_permitted_opens = 0;
124 * If this is true, all opens are permitted. This is the case on the server
125 * on which we have to trust the client anyway, and the user could do
126 * anything after logging in anyway.
128 static int all_opens_permitted = 0;
130 /* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */
131 static int have_hostname_in_open = 0;
133 /* AF_UNSPEC or AF_INET or AF_INET6 */
136 /* Sets specific protocol options. */
139 channel_set_options(int hostname_in_open)
141 have_hostname_in_open = hostname_in_open;
145 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
146 * called by the server, because the user could connect to any port anyway,
147 * and the server has no way to know but to trust the client anyway.
151 channel_permit_all_opens()
153 all_opens_permitted = 1;
156 /* lookup channel by id */
159 channel_lookup(int id)
162 if (id < 0 || id > channels_alloc) {
163 log("channel_lookup: %d: bad id", id);
167 if (c->type == SSH_CHANNEL_FREE) {
168 log("channel_lookup: %d: bad id: channel free", id);
175 * Register filedescriptors for a channel, used when allocating a channel or
176 * when the channel consumer/producer is ready, e.g. shell exec'd
180 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
181 int extusage, int nonblock)
183 /* Update the maximum file descriptor value. */
184 channel_max_fd = MAX(channel_max_fd, rfd);
185 channel_max_fd = MAX(channel_max_fd, wfd);
186 channel_max_fd = MAX(channel_max_fd, efd);
188 /* XXX set close-on-exec -markus */
192 c->sock = (rfd == wfd) ? rfd : -1;
194 c->extended_usage = extusage;
196 /* enable nonblocking mode */
208 * Allocate a new channel object and set its type and socket. This will cause
209 * remote_name to be freed.
213 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
214 int window, int maxpack, int extusage, char *remote_name, int nonblock)
219 /* Do initial allocation if this is the first call. */
220 if (channels_alloc == 0) {
223 channels = xmalloc(channels_alloc * sizeof(Channel));
224 for (i = 0; i < channels_alloc; i++)
225 channels[i].type = SSH_CHANNEL_FREE;
227 * Kludge: arrange a call to channel_stop_listening if we
228 * terminate with fatal().
230 fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
232 /* Try to find a free slot where to put the new channel. */
233 for (found = -1, i = 0; i < channels_alloc; i++)
234 if (channels[i].type == SSH_CHANNEL_FREE) {
235 /* Found a free slot. */
240 /* There are no free slots. Take last+1 slot and expand the array. */
241 found = channels_alloc;
242 channels_alloc += 10;
243 debug2("channel: expanding %d", channels_alloc);
244 channels = xrealloc(channels, channels_alloc * sizeof(Channel));
245 for (i = found; i < channels_alloc; i++)
246 channels[i].type = SSH_CHANNEL_FREE;
248 /* Initialize and return new channel number. */
249 c = &channels[found];
250 buffer_init(&c->input);
251 buffer_init(&c->output);
252 buffer_init(&c->extended);
253 chan_init_iostates(c);
254 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
258 c->local_window = window;
259 c->local_window_max = window;
260 c->local_consumed = 0;
261 c->local_maxpacket = maxpack;
263 c->remote_name = remote_name;
264 c->remote_window = 0;
265 c->remote_maxpacket = 0;
269 c->dettach_user = NULL;
270 c->input_filter = NULL;
271 debug("channel %d: new [%s]", found, remote_name);
274 /* old interface XXX */
276 channel_allocate(int type, int sock, char *remote_name)
278 return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name, 1);
282 /* Close all channel fd/socket. */
285 channel_close_fds(Channel *c)
305 /* Free the channel and close its fd/socket. */
310 Channel *c = channel_lookup(id);
311 char *s = channel_open_message();
314 packet_disconnect("channel free: bad local channel %d", id);
315 debug("channel_free: channel %d: status: %s", id, s);
318 if (c->dettach_user != NULL) {
319 debug("channel_free: channel %d: dettaching channel user", id);
320 c->dettach_user(c->self, NULL);
323 shutdown(c->sock, SHUT_RDWR);
324 channel_close_fds(c);
325 buffer_free(&c->input);
326 buffer_free(&c->output);
327 buffer_free(&c->extended);
328 c->type = SSH_CHANNEL_FREE;
329 if (c->remote_name) {
330 xfree(c->remote_name);
331 c->remote_name = NULL;
336 * 'channel_pre*' are called just before select() to add any bits relevant to
337 * channels in the select bitmasks.
340 * 'channel_post*': perform any appropriate operations for channels which
341 * have events pending.
343 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
344 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
345 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
348 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
350 FD_SET(c->sock, readset);
354 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
356 debug3("channel %d: waiting for connection", c->self);
357 FD_SET(c->sock, writeset);
361 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
363 if (buffer_len(&c->input) < packet_get_maxsize())
364 FD_SET(c->sock, readset);
365 if (buffer_len(&c->output) > 0)
366 FD_SET(c->sock, writeset);
370 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
372 /* test whether sockets are 'alive' for read/write */
373 if (c->istate == CHAN_INPUT_OPEN)
374 if (buffer_len(&c->input) < packet_get_maxsize())
375 FD_SET(c->sock, readset);
376 if (c->ostate == CHAN_OUTPUT_OPEN ||
377 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
378 if (buffer_len(&c->output) > 0) {
379 FD_SET(c->sock, writeset);
380 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
387 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
389 if (c->istate == CHAN_INPUT_OPEN &&
390 c->remote_window > 0 &&
391 buffer_len(&c->input) < c->remote_window)
392 FD_SET(c->rfd, readset);
393 if (c->ostate == CHAN_OUTPUT_OPEN ||
394 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
395 if (buffer_len(&c->output) > 0) {
396 FD_SET(c->wfd, writeset);
397 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
401 /** XXX check close conditions, too */
403 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
404 buffer_len(&c->extended) > 0)
405 FD_SET(c->efd, writeset);
406 else if (c->extended_usage == CHAN_EXTENDED_READ &&
407 buffer_len(&c->extended) < c->remote_window)
408 FD_SET(c->efd, readset);
413 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
415 if (buffer_len(&c->input) == 0) {
416 packet_start(SSH_MSG_CHANNEL_CLOSE);
417 packet_put_int(c->remote_id);
419 c->type = SSH_CHANNEL_CLOSED;
420 debug("Closing channel %d after input drain.", c->self);
425 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
427 if (buffer_len(&c->output) == 0)
428 channel_free(c->self);
430 FD_SET(c->sock, writeset);
434 * This is a special state for X11 authentication spoofing. An opened X11
435 * connection (when authentication spoofing is being done) remains in this
436 * state until the first packet has been completely read. The authentication
437 * data in that packet is then substituted by the real data if it matches the
438 * fake data, and the channel is put into normal mode.
439 * XXX All this happens at the client side.
442 x11_open_helper(Channel *c)
445 u_int proto_len, data_len;
447 /* Check if the fixed size part of the packet is in buffer. */
448 if (buffer_len(&c->output) < 12)
451 /* Parse the lengths of variable-length fields. */
452 ucp = (u_char *) buffer_ptr(&c->output);
453 if (ucp[0] == 0x42) { /* Byte order MSB first. */
454 proto_len = 256 * ucp[6] + ucp[7];
455 data_len = 256 * ucp[8] + ucp[9];
456 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
457 proto_len = ucp[6] + 256 * ucp[7];
458 data_len = ucp[8] + 256 * ucp[9];
460 debug("Initial X11 packet contains bad byte order byte: 0x%x",
465 /* Check if the whole packet is in buffer. */
466 if (buffer_len(&c->output) <
467 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
470 /* Check if authentication protocol matches. */
471 if (proto_len != strlen(x11_saved_proto) ||
472 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
473 debug("X11 connection uses different authentication protocol.");
476 /* Check if authentication data matches our fake data. */
477 if (data_len != x11_fake_data_len ||
478 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
479 x11_fake_data, x11_fake_data_len) != 0) {
480 debug("X11 auth data does not match fake data.");
483 /* Check fake data length */
484 if (x11_fake_data_len != x11_saved_data_len) {
485 error("X11 fake_data_len %d != saved_data_len %d",
486 x11_fake_data_len, x11_saved_data_len);
490 * Received authentication protocol and data match
491 * our fake data. Substitute the fake data with real
494 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
495 x11_saved_data, x11_saved_data_len);
500 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
502 int ret = x11_open_helper(c);
504 /* Start normal processing for the channel. */
505 c->type = SSH_CHANNEL_OPEN;
506 channel_pre_open_13(c, readset, writeset);
507 } else if (ret == -1) {
509 * We have received an X11 connection that has bad
510 * authentication information.
512 log("X11 connection rejected because of wrong authentication.\r\n");
513 buffer_clear(&c->input);
514 buffer_clear(&c->output);
517 c->type = SSH_CHANNEL_CLOSED;
518 packet_start(SSH_MSG_CHANNEL_CLOSE);
519 packet_put_int(c->remote_id);
525 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
527 int ret = x11_open_helper(c);
529 c->type = SSH_CHANNEL_OPEN;
531 channel_pre_open_20(c, readset, writeset);
533 channel_pre_open_15(c, readset, writeset);
534 } else if (ret == -1) {
535 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
536 chan_read_failed(c); /** force close? */
537 chan_write_failed(c);
538 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
542 /* This is our fake X11 server socket. */
544 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
546 struct sockaddr addr;
549 char buf[16384], *remote_ipaddr;
552 if (FD_ISSET(c->sock, readset)) {
553 debug("X11 connection requested.");
554 addrlen = sizeof(addr);
555 newsock = accept(c->sock, &addr, &addrlen);
557 error("accept: %.100s", strerror(errno));
560 remote_ipaddr = get_peer_ipaddr(newsock);
561 remote_port = get_peer_port(newsock);
562 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
563 remote_ipaddr, remote_port);
565 newch = channel_new("x11",
566 SSH_CHANNEL_OPENING, newsock, newsock, -1,
567 c->local_window_max, c->local_maxpacket,
570 packet_start(SSH2_MSG_CHANNEL_OPEN);
571 packet_put_cstring("x11");
572 packet_put_int(newch);
573 packet_put_int(c->local_window_max);
574 packet_put_int(c->local_maxpacket);
575 /* originator ipaddr and port */
576 packet_put_cstring(remote_ipaddr);
577 if (datafellows & SSH_BUG_X11FWD) {
578 debug("ssh2 x11 bug compat mode");
580 packet_put_int(remote_port);
584 packet_start(SSH_SMSG_X11_OPEN);
585 packet_put_int(newch);
586 if (have_hostname_in_open)
587 packet_put_string(buf, strlen(buf));
590 xfree(remote_ipaddr);
595 * This socket is listening for connections to a forwarded TCP/IP port.
598 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
600 struct sockaddr addr;
603 char buf[1024], *remote_hostname, *rtype;
606 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
607 "forwarded-tcpip" : "direct-tcpip";
609 if (FD_ISSET(c->sock, readset)) {
610 debug("Connection to port %d forwarding "
611 "to %.100s port %d requested.",
612 c->listening_port, c->path, c->host_port);
613 addrlen = sizeof(addr);
614 newsock = accept(c->sock, &addr, &addrlen);
616 error("accept: %.100s", strerror(errno));
619 remote_hostname = get_remote_hostname(newsock);
620 remote_port = get_peer_port(newsock);
621 snprintf(buf, sizeof buf,
622 "listen port %d for %.100s port %d, "
623 "connect from %.200s port %d",
624 c->listening_port, c->path, c->host_port,
625 remote_hostname, remote_port);
627 newch = channel_new(rtype,
628 SSH_CHANNEL_OPENING, newsock, newsock, -1,
629 c->local_window_max, c->local_maxpacket,
632 packet_start(SSH2_MSG_CHANNEL_OPEN);
633 packet_put_cstring(rtype);
634 packet_put_int(newch);
635 packet_put_int(c->local_window_max);
636 packet_put_int(c->local_maxpacket);
637 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
638 /* listen address, port */
639 packet_put_string(c->path, strlen(c->path));
640 packet_put_int(c->listening_port);
642 /* target host, port */
643 packet_put_string(c->path, strlen(c->path));
644 packet_put_int(c->host_port);
646 /* originator host and port */
647 packet_put_cstring(remote_hostname);
648 packet_put_int(remote_port);
651 packet_start(SSH_MSG_PORT_OPEN);
652 packet_put_int(newch);
653 packet_put_string(c->path, strlen(c->path));
654 packet_put_int(c->host_port);
655 if (have_hostname_in_open) {
656 packet_put_string(buf, strlen(buf));
660 xfree(remote_hostname);
665 * This is the authentication agent socket listening for connections from
669 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
671 struct sockaddr addr;
675 if (FD_ISSET(c->sock, readset)) {
676 addrlen = sizeof(addr);
677 newsock = accept(c->sock, &addr, &addrlen);
679 error("accept from auth socket: %.100s", strerror(errno));
682 newch = channel_new("accepted auth socket",
683 SSH_CHANNEL_OPENING, newsock, newsock, -1,
684 c->local_window_max, c->local_maxpacket,
685 0, xstrdup("accepted auth socket"), 1);
687 packet_start(SSH2_MSG_CHANNEL_OPEN);
688 packet_put_cstring("auth-agent@openssh.com");
689 packet_put_int(newch);
690 packet_put_int(c->local_window_max);
691 packet_put_int(c->local_maxpacket);
693 packet_start(SSH_SMSG_AGENT_OPEN);
694 packet_put_int(newch);
701 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
703 if (FD_ISSET(c->sock, writeset)) {
705 int sz = sizeof(err);
706 c->type = SSH_CHANNEL_OPEN;
707 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err, &sz) < 0) {
708 debug("getsockopt SO_ERROR failed");
711 debug("channel %d: connected)", c->self);
713 debug("channel %d: not connected: %s",
714 c->self, strerror(err));
716 chan_write_failed(c);
723 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
729 FD_ISSET(c->rfd, readset)) {
730 len = read(c->rfd, buf, sizeof(buf));
731 if (len < 0 && (errno == EINTR || errno == EAGAIN))
734 debug("channel %d: read<=0 rfd %d len %d",
735 c->self, c->rfd, len);
737 buffer_consume(&c->output, buffer_len(&c->output));
738 c->type = SSH_CHANNEL_INPUT_DRAINING;
739 debug("Channel %d status set to input draining.", c->self);
745 if(c->input_filter != NULL) {
746 if (c->input_filter(c, buf, len) == -1) {
747 debug("filter stops channel %d", c->self);
751 buffer_append(&c->input, buf, len);
757 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
761 /* Send buffered output data to the socket. */
763 FD_ISSET(c->wfd, writeset) &&
764 buffer_len(&c->output) > 0) {
765 len = write(c->wfd, buffer_ptr(&c->output),
766 buffer_len(&c->output));
767 if (len < 0 && (errno == EINTR || errno == EAGAIN))
771 buffer_consume(&c->output, buffer_len(&c->output));
772 debug("Channel %d status set to input draining.", c->self);
773 c->type = SSH_CHANNEL_INPUT_DRAINING;
775 chan_write_failed(c);
779 buffer_consume(&c->output, len);
780 if (compat20 && len > 0) {
781 c->local_consumed += len;
787 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
792 /** XXX handle drain efd, too */
794 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
795 FD_ISSET(c->efd, writeset) &&
796 buffer_len(&c->extended) > 0) {
797 len = write(c->efd, buffer_ptr(&c->extended),
798 buffer_len(&c->extended));
799 debug2("channel %d: written %d to efd %d",
800 c->self, len, c->efd);
802 buffer_consume(&c->extended, len);
803 c->local_consumed += len;
805 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
806 FD_ISSET(c->efd, readset)) {
807 len = read(c->efd, buf, sizeof(buf));
808 debug2("channel %d: read %d from efd %d",
809 c->self, len, c->efd);
811 debug("channel %d: closing efd %d",
816 buffer_append(&c->extended, buf, len);
822 channel_check_window(Channel *c, fd_set * readset, fd_set * writeset)
824 if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
825 c->local_window < c->local_window_max/2 &&
826 c->local_consumed > 0) {
827 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
828 packet_put_int(c->remote_id);
829 packet_put_int(c->local_consumed);
831 debug2("channel %d: window %d sent adjust %d",
832 c->self, c->local_window,
834 c->local_window += c->local_consumed;
835 c->local_consumed = 0;
841 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
843 channel_handle_rfd(c, readset, writeset);
844 channel_handle_wfd(c, readset, writeset);
848 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
850 channel_handle_rfd(c, readset, writeset);
851 channel_handle_wfd(c, readset, writeset);
852 channel_handle_efd(c, readset, writeset);
853 channel_check_window(c, readset, writeset);
857 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
860 /* Send buffered output data to the socket. */
861 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
862 len = write(c->sock, buffer_ptr(&c->output),
863 buffer_len(&c->output));
865 buffer_consume(&c->output, buffer_len(&c->output));
867 buffer_consume(&c->output, len);
872 channel_handler_init_20(void)
874 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
875 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
876 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
877 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
878 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
879 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
880 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
882 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
883 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
884 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
885 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
886 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
887 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
891 channel_handler_init_13(void)
893 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
894 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
895 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
896 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
897 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
898 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
899 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
900 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
902 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
903 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
904 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
905 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
906 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
907 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
911 channel_handler_init_15(void)
913 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
914 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
915 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
916 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
917 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
918 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
920 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
921 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
922 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
923 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
924 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
928 channel_handler_init(void)
931 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
932 channel_pre[i] = NULL;
933 channel_post[i] = NULL;
936 channel_handler_init_20();
938 channel_handler_init_13();
940 channel_handler_init_15();
944 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
946 static int did_init = 0;
951 channel_handler_init();
954 for (i = 0; i < channels_alloc; i++) {
956 if (c->type == SSH_CHANNEL_FREE)
958 if (ftab[c->type] == NULL)
960 (*ftab[c->type])(c, readset, writeset);
961 chan_delete_if_full_closed(c);
966 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp)
971 n = MAX(*maxfdp, channel_max_fd);
973 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
974 if (*readsetp == NULL || n > *maxfdp) {
979 *readsetp = xmalloc(sz);
980 *writesetp = xmalloc(sz);
983 memset(*readsetp, 0, sz);
984 memset(*writesetp, 0, sz);
986 channel_handler(channel_pre, *readsetp, *writesetp);
990 channel_after_select(fd_set * readset, fd_set * writeset)
992 channel_handler(channel_post, readset, writeset);
995 /* If there is data to send to the connection, enqueue some of it now. */
998 channel_output_poll()
1003 for (i = 0; i < channels_alloc; i++) {
1006 /* We are only interested in channels that can have buffered incoming data. */
1008 if (c->type != SSH_CHANNEL_OPEN &&
1009 c->type != SSH_CHANNEL_INPUT_DRAINING)
1012 if (c->type != SSH_CHANNEL_OPEN)
1014 if (c->istate != CHAN_INPUT_OPEN &&
1015 c->istate != CHAN_INPUT_WAIT_DRAIN)
1019 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1020 debug("channel: %d: no data after CLOSE", c->self);
1024 /* Get the amount of buffered data for this channel. */
1025 len = buffer_len(&c->input);
1027 /* Send some data for the other side over the secure connection. */
1029 if (len > c->remote_window)
1030 len = c->remote_window;
1031 if (len > c->remote_maxpacket)
1032 len = c->remote_maxpacket;
1034 if (packet_is_interactive()) {
1038 /* Keep the packets at reasonable size. */
1039 if (len > packet_get_maxsize()/2)
1040 len = packet_get_maxsize()/2;
1044 packet_start(compat20 ?
1045 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1046 packet_put_int(c->remote_id);
1047 packet_put_string(buffer_ptr(&c->input), len);
1049 buffer_consume(&c->input, len);
1050 c->remote_window -= len;
1052 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1054 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1056 * input-buffer is empty and read-socket shutdown:
1057 * tell peer, that we will not send more data: send IEOF
1061 /* Send extended data, i.e. stderr */
1063 c->remote_window > 0 &&
1064 (len = buffer_len(&c->extended)) > 0 &&
1065 c->extended_usage == CHAN_EXTENDED_READ) {
1066 if (len > c->remote_window)
1067 len = c->remote_window;
1068 if (len > c->remote_maxpacket)
1069 len = c->remote_maxpacket;
1070 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1071 packet_put_int(c->remote_id);
1072 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1073 packet_put_string(buffer_ptr(&c->extended), len);
1075 buffer_consume(&c->extended, len);
1076 c->remote_window -= len;
1082 * This is called when a packet of type CHANNEL_DATA has just been received.
1083 * The message type has already been consumed, but channel number and data is
1088 channel_input_data(int type, int plen, void *ctxt)
1095 /* Get the channel number and verify it. */
1096 id = packet_get_int();
1097 c = channel_lookup(id);
1099 packet_disconnect("Received data for nonexistent channel %d.", id);
1101 /* Ignore any data for non-open channels (might happen on close) */
1102 if (c->type != SSH_CHANNEL_OPEN &&
1103 c->type != SSH_CHANNEL_X11_OPEN)
1106 /* same for protocol 1.5 if output end is no longer open */
1107 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1111 data = packet_get_string(&data_len);
1115 if (data_len > c->local_maxpacket) {
1116 log("channel %d: rcvd big packet %d, maxpack %d",
1117 c->self, data_len, c->local_maxpacket);
1119 if (data_len > c->local_window) {
1120 log("channel %d: rcvd too much data %d, win %d",
1121 c->self, data_len, c->local_window);
1125 c->local_window -= data_len;
1127 packet_integrity_check(plen, 4 + 4 + data_len, type);
1129 buffer_append(&c->output, data, data_len);
1133 channel_input_extended_data(int type, int plen, void *ctxt)
1141 /* Get the channel number and verify it. */
1142 id = packet_get_int();
1143 c = channel_lookup(id);
1146 packet_disconnect("Received extended_data for bad channel %d.", id);
1147 if (c->type != SSH_CHANNEL_OPEN) {
1148 log("channel %d: ext data for non open", id);
1151 tcode = packet_get_int();
1153 c->extended_usage != CHAN_EXTENDED_WRITE ||
1154 tcode != SSH2_EXTENDED_DATA_STDERR) {
1155 log("channel %d: bad ext data", c->self);
1158 data = packet_get_string(&data_len);
1160 if (data_len > c->local_window) {
1161 log("channel %d: rcvd too much extended_data %d, win %d",
1162 c->self, data_len, c->local_window);
1166 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1167 c->local_window -= data_len;
1168 buffer_append(&c->extended, data, data_len);
1174 * Returns true if no channel has too much buffered data, and false if one or
1175 * more channel is overfull.
1179 channel_not_very_much_buffered_data()
1184 for (i = 0; i < channels_alloc; i++) {
1186 if (c->type == SSH_CHANNEL_OPEN) {
1187 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
1188 debug("channel %d: big input buffer %d",
1189 c->self, buffer_len(&c->input));
1192 if (buffer_len(&c->output) > packet_get_maxsize()) {
1193 debug("channel %d: big output buffer %d",
1194 c->self, buffer_len(&c->output));
1203 channel_input_ieof(int type, int plen, void *ctxt)
1208 packet_integrity_check(plen, 4, type);
1210 id = packet_get_int();
1211 c = channel_lookup(id);
1213 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1218 channel_input_close(int type, int plen, void *ctxt)
1223 packet_integrity_check(plen, 4, type);
1225 id = packet_get_int();
1226 c = channel_lookup(id);
1228 packet_disconnect("Received close for nonexistent channel %d.", id);
1231 * Send a confirmation that we have closed the channel and no more
1232 * data is coming for it.
1234 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1235 packet_put_int(c->remote_id);
1239 * If the channel is in closed state, we have sent a close request,
1240 * and the other side will eventually respond with a confirmation.
1241 * Thus, we cannot free the channel here, because then there would be
1242 * no-one to receive the confirmation. The channel gets freed when
1243 * the confirmation arrives.
1245 if (c->type != SSH_CHANNEL_CLOSED) {
1247 * Not a closed channel - mark it as draining, which will
1248 * cause it to be freed later.
1250 buffer_consume(&c->input, buffer_len(&c->input));
1251 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1255 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1257 channel_input_oclose(int type, int plen, void *ctxt)
1259 int id = packet_get_int();
1260 Channel *c = channel_lookup(id);
1261 packet_integrity_check(plen, 4, type);
1263 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1264 chan_rcvd_oclose(c);
1268 channel_input_close_confirmation(int type, int plen, void *ctxt)
1270 int id = packet_get_int();
1271 Channel *c = channel_lookup(id);
1275 packet_disconnect("Received close confirmation for "
1276 "out-of-range channel %d.", id);
1277 if (c->type != SSH_CHANNEL_CLOSED)
1278 packet_disconnect("Received close confirmation for "
1279 "non-closed channel %d (type %d).", id, c->type);
1280 channel_free(c->self);
1284 channel_input_open_confirmation(int type, int plen, void *ctxt)
1290 packet_integrity_check(plen, 4 + 4, type);
1292 id = packet_get_int();
1293 c = channel_lookup(id);
1295 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1296 packet_disconnect("Received open confirmation for "
1297 "non-opening channel %d.", id);
1298 remote_id = packet_get_int();
1299 /* Record the remote channel number and mark that the channel is now open. */
1300 c->remote_id = remote_id;
1301 c->type = SSH_CHANNEL_OPEN;
1304 c->remote_window = packet_get_int();
1305 c->remote_maxpacket = packet_get_int();
1307 if (c->cb_fn != NULL && c->cb_event == type) {
1308 debug2("callback start");
1309 c->cb_fn(c->self, c->cb_arg);
1310 debug2("callback done");
1312 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1313 c->remote_window, c->remote_maxpacket);
1318 channel_input_open_failure(int type, int plen, void *ctxt)
1324 packet_integrity_check(plen, 4, type);
1326 id = packet_get_int();
1327 c = channel_lookup(id);
1329 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1330 packet_disconnect("Received open failure for "
1331 "non-opening channel %d.", id);
1333 int reason = packet_get_int();
1334 char *msg = packet_get_string(NULL);
1335 char *lang = packet_get_string(NULL);
1336 log("channel_open_failure: %d: reason %d: %s", id, reason, msg);
1341 /* Free the channel. This will also close the socket. */
1346 channel_input_channel_request(int type, int plen, void *ctxt)
1351 id = packet_get_int();
1352 c = channel_lookup(id);
1355 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1356 packet_disconnect("Received request for "
1357 "non-open channel %d.", id);
1358 if (c->cb_fn != NULL && c->cb_event == type) {
1359 debug2("callback start");
1360 c->cb_fn(c->self, c->cb_arg);
1361 debug2("callback done");
1363 char *service = packet_get_string(NULL);
1364 debug("channel: %d rcvd request for %s", c->self, service);
1365 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1371 channel_input_window_adjust(int type, int plen, void *ctxt)
1379 /* Get the channel number and verify it. */
1380 id = packet_get_int();
1381 c = channel_lookup(id);
1383 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1384 log("Received window adjust for "
1385 "non-open channel %d.", id);
1388 adjust = packet_get_int();
1390 debug2("channel %d: rcvd adjust %d", id, adjust);
1391 c->remote_window += adjust;
1395 * Stops listening for channels, and removes any unix domain sockets that we
1400 channel_stop_listening()
1403 for (i = 0; i < channels_alloc; i++) {
1404 switch (channels[i].type) {
1405 case SSH_CHANNEL_AUTH_SOCKET:
1406 close(channels[i].sock);
1407 unlink(channels[i].path);
1410 case SSH_CHANNEL_PORT_LISTENER:
1411 case SSH_CHANNEL_RPORT_LISTENER:
1412 case SSH_CHANNEL_X11_LISTENER:
1413 close(channels[i].sock);
1423 * Closes the sockets/fds of all channels. This is used to close extra file
1424 * descriptors after a fork.
1431 for (i = 0; i < channels_alloc; i++)
1432 if (channels[i].type != SSH_CHANNEL_FREE)
1433 channel_close_fds(&channels[i]);
1436 /* Returns true if any channel is still open. */
1439 channel_still_open()
1442 for (i = 0; i < channels_alloc; i++)
1443 switch (channels[i].type) {
1444 case SSH_CHANNEL_FREE:
1445 case SSH_CHANNEL_X11_LISTENER:
1446 case SSH_CHANNEL_PORT_LISTENER:
1447 case SSH_CHANNEL_RPORT_LISTENER:
1448 case SSH_CHANNEL_CLOSED:
1449 case SSH_CHANNEL_AUTH_SOCKET:
1450 case SSH_CHANNEL_CONNECTING: /* XXX ??? */
1452 case SSH_CHANNEL_LARVAL:
1454 fatal("cannot happen: SSH_CHANNEL_LARVAL");
1456 case SSH_CHANNEL_OPENING:
1457 case SSH_CHANNEL_OPEN:
1458 case SSH_CHANNEL_X11_OPEN:
1460 case SSH_CHANNEL_INPUT_DRAINING:
1461 case SSH_CHANNEL_OUTPUT_DRAINING:
1463 fatal("cannot happen: OUT_DRAIN");
1466 fatal("channel_still_open: bad channel type %d", channels[i].type);
1473 * Returns a message describing the currently open forwarded connections,
1474 * suitable for sending to the client. The message contains crlf pairs for
1479 channel_open_message()
1485 buffer_init(&buffer);
1486 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
1487 buffer_append(&buffer, buf, strlen(buf));
1488 for (i = 0; i < channels_alloc; i++) {
1489 Channel *c = &channels[i];
1491 case SSH_CHANNEL_FREE:
1492 case SSH_CHANNEL_X11_LISTENER:
1493 case SSH_CHANNEL_PORT_LISTENER:
1494 case SSH_CHANNEL_RPORT_LISTENER:
1495 case SSH_CHANNEL_CLOSED:
1496 case SSH_CHANNEL_AUTH_SOCKET:
1498 case SSH_CHANNEL_LARVAL:
1499 case SSH_CHANNEL_OPENING:
1500 case SSH_CHANNEL_CONNECTING:
1501 case SSH_CHANNEL_OPEN:
1502 case SSH_CHANNEL_X11_OPEN:
1503 case SSH_CHANNEL_INPUT_DRAINING:
1504 case SSH_CHANNEL_OUTPUT_DRAINING:
1505 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
1506 c->self, c->remote_name,
1507 c->type, c->remote_id,
1508 c->istate, buffer_len(&c->input),
1509 c->ostate, buffer_len(&c->output),
1511 buffer_append(&buffer, buf, strlen(buf));
1514 fatal("channel_open_message: bad channel type %d", c->type);
1518 buffer_append(&buffer, "\0", 1);
1519 cp = xstrdup(buffer_ptr(&buffer));
1520 buffer_free(&buffer);
1525 * Initiate forwarding of connections to local port "port" through the secure
1526 * channel to host:port from remote side.
1529 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
1530 u_short port_to_connect, int gateway_ports)
1532 channel_request_forwarding(
1534 host_to_connect, port_to_connect,
1535 gateway_ports, /*remote_fwd*/ 0);
1539 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
1540 * (SSH_CHANNEL_RPORT_LISTENER).
1543 channel_request_forwarding(
1544 const char *listen_address, u_short listen_port,
1545 const char *host_to_connect, u_short port_to_connect,
1546 int gateway_ports, int remote_fwd)
1548 int success, ch, sock, on = 1, ctype;
1549 struct addrinfo hints, *ai, *aitop;
1550 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1552 struct linger linger;
1555 host = listen_address;
1556 ctype = SSH_CHANNEL_RPORT_LISTENER;
1558 host = host_to_connect;
1559 ctype =SSH_CHANNEL_PORT_LISTENER;
1562 if (strlen(host) > sizeof(channels[0].path) - 1)
1563 packet_disconnect("Forward host name too long.");
1565 /* XXX listen_address is currently ignored */
1567 * getaddrinfo returns a loopback address if the hostname is
1568 * set to NULL and hints.ai_flags is not AI_PASSIVE
1570 memset(&hints, 0, sizeof(hints));
1571 hints.ai_family = IPv4or6;
1572 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
1573 hints.ai_socktype = SOCK_STREAM;
1574 snprintf(strport, sizeof strport, "%d", listen_port);
1575 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
1576 packet_disconnect("getaddrinfo: fatal error");
1579 for (ai = aitop; ai; ai = ai->ai_next) {
1580 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1582 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1583 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1584 error("channel_request_forwarding: getnameinfo failed");
1587 /* Create a port to listen for the host. */
1588 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1590 /* this is no error since kernel may not support ipv6 */
1591 verbose("socket: %.100s", strerror(errno));
1595 * Set socket options. We would like the socket to disappear
1596 * as soon as it has been closed for whatever reason.
1598 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
1600 linger.l_linger = 5;
1601 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
1602 debug("Local forwarding listening on %s port %s.", ntop, strport);
1604 /* Bind the socket to the address. */
1605 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1606 /* address can be in use ipv6 address is already bound */
1608 error("bind: %.100s", strerror(errno));
1610 verbose("bind: %.100s", strerror(errno));
1615 /* Start listening for connections on the socket. */
1616 if (listen(sock, 5) < 0) {
1617 error("listen: %.100s", strerror(errno));
1621 /* Allocate a channel number for the socket. */
1622 ch = channel_new("port listener", ctype, sock, sock, -1,
1623 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1624 0, xstrdup("port listener"), 1);
1625 strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
1626 channels[ch].host_port = port_to_connect;
1627 channels[ch].listening_port = listen_port;
1631 packet_disconnect("cannot listen port: %d", listen_port); /*XXX ?disconnect? */
1632 freeaddrinfo(aitop);
1636 * Initiate forwarding of connections to port "port" on remote host through
1637 * the secure channel to host:port from local side.
1641 channel_request_remote_forwarding(u_short listen_port,
1642 const char *host_to_connect, u_short port_to_connect)
1644 int payload_len, type, success = 0;
1646 /* Record locally that connection to this host/port is permitted. */
1647 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
1648 fatal("channel_request_remote_forwarding: too many forwards");
1650 /* Send the forward request to the remote side. */
1652 const char *address_to_bind = "0.0.0.0";
1653 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1654 packet_put_cstring("tcpip-forward");
1655 packet_put_char(0); /* boolean: want reply */
1656 packet_put_cstring(address_to_bind);
1657 packet_put_int(listen_port);
1659 packet_write_wait();
1660 /* Assume that server accepts the request */
1663 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
1664 packet_put_int(listen_port);
1665 packet_put_cstring(host_to_connect);
1666 packet_put_int(port_to_connect);
1668 packet_write_wait();
1670 /* Wait for response from the remote side. */
1671 type = packet_read(&payload_len);
1673 case SSH_SMSG_SUCCESS:
1676 case SSH_SMSG_FAILURE:
1677 log("Warning: Server denied remote port forwarding.");
1680 /* Unknown packet */
1681 packet_disconnect("Protocol error for port forward request:"
1682 "received packet type %d.", type);
1686 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
1687 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
1688 permitted_opens[num_permitted_opens].listen_port = listen_port;
1689 num_permitted_opens++;
1694 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
1695 * listening for the port, and sends back a success reply (or disconnect
1696 * message if there was an error). This never returns if there was an error.
1700 channel_input_port_forward_request(int is_root, int gateway_ports)
1702 u_short port, host_port;
1705 /* Get arguments from the packet. */
1706 port = packet_get_int();
1707 hostname = packet_get_string(NULL);
1708 host_port = packet_get_int();
1712 * Check that an unprivileged user is not trying to forward a
1715 if (port < IPPORT_RESERVED && !is_root)
1716 packet_disconnect("Requested forwarding of port %d but user is not root.",
1719 /* Initiate forwarding */
1720 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
1722 /* Free the argument string. */
1726 /* XXX move to aux.c */
1728 channel_connect_to(const char *host, u_short host_port)
1730 struct addrinfo hints, *ai, *aitop;
1731 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1735 memset(&hints, 0, sizeof(hints));
1736 hints.ai_family = IPv4or6;
1737 hints.ai_socktype = SOCK_STREAM;
1738 snprintf(strport, sizeof strport, "%d", host_port);
1739 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
1740 error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
1743 for (ai = aitop; ai; ai = ai->ai_next) {
1744 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1746 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1747 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1748 error("channel_connect_to: getnameinfo failed");
1751 /* Create the socket. */
1752 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1754 error("socket: %.100s", strerror(errno));
1757 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
1758 fatal("connect_to: F_SETFL: %s", strerror(errno));
1759 /* Connect to the host/port. */
1760 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
1761 errno != EINPROGRESS) {
1762 error("connect %.100s port %s: %.100s", ntop, strport,
1765 continue; /* fail -- try next */
1767 break; /* success */
1770 freeaddrinfo(aitop);
1772 error("connect %.100s port %d: failed.", host, host_port);
1779 channel_connect_by_listen_adress(u_short listen_port)
1782 for (i = 0; i < num_permitted_opens; i++)
1783 if (permitted_opens[i].listen_port == listen_port)
1784 return channel_connect_to(
1785 permitted_opens[i].host_to_connect,
1786 permitted_opens[i].port_to_connect);
1787 error("WARNING: Server requests forwarding for unknown listen_port %d",
1793 * This is called after receiving PORT_OPEN message. This attempts to
1794 * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
1795 * or CHANNEL_OPEN_FAILURE.
1799 channel_input_port_open(int type, int plen, void *ctxt)
1802 char *host, *originator_string;
1803 int remote_channel, sock = -1, newch, i, denied;
1804 u_int host_len, originator_len;
1806 /* Get remote channel number. */
1807 remote_channel = packet_get_int();
1809 /* Get host name to connect to. */
1810 host = packet_get_string(&host_len);
1812 /* Get port to connect to. */
1813 host_port = packet_get_int();
1815 /* Get remote originator name. */
1816 if (have_hostname_in_open) {
1817 originator_string = packet_get_string(&originator_len);
1818 originator_len += 4; /* size of packet_int */
1820 originator_string = xstrdup("unknown (remote did not supply name)");
1821 originator_len = 0; /* no originator supplied */
1824 packet_integrity_check(plen,
1825 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN);
1827 /* Check if opening that port is permitted. */
1829 if (!all_opens_permitted) {
1830 /* Go trough all permitted ports. */
1831 for (i = 0; i < num_permitted_opens; i++)
1832 if (permitted_opens[i].port_to_connect == host_port &&
1833 strcmp(permitted_opens[i].host_to_connect, host) == 0)
1836 /* Check if we found the requested port among those permitted. */
1837 if (i >= num_permitted_opens) {
1838 /* The port is not permitted. */
1839 log("Received request to connect to %.100s:%d, but the request was denied.",
1844 sock = denied ? -1 : channel_connect_to(host, host_port);
1846 /* Allocate a channel for this connection. */
1847 newch = channel_allocate(SSH_CHANNEL_CONNECTING,
1848 sock, originator_string);
1849 /*XXX delay answer? */
1850 channels[newch].remote_id = remote_channel;
1852 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1853 packet_put_int(remote_channel);
1854 packet_put_int(newch);
1857 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1858 packet_put_int(remote_channel);
1865 * Creates an internet domain socket for listening for X11 connections.
1866 * Returns a suitable value for the DISPLAY variable, or NULL if an error
1870 #define NUM_SOCKS 10
1873 x11_create_display_inet(int screen_number, int x11_display_offset)
1875 int display_number, sock;
1877 struct addrinfo hints, *ai, *aitop;
1878 char strport[NI_MAXSERV];
1879 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
1881 char hostname[MAXHOSTNAMELEN];
1883 for (display_number = x11_display_offset;
1884 display_number < MAX_DISPLAYS;
1886 port = 6000 + display_number;
1887 memset(&hints, 0, sizeof(hints));
1888 hints.ai_family = IPv4or6;
1889 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
1890 hints.ai_socktype = SOCK_STREAM;
1891 snprintf(strport, sizeof strport, "%d", port);
1892 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
1893 error("getaddrinfo: %.100s", gai_strerror(gaierr));
1896 for (ai = aitop; ai; ai = ai->ai_next) {
1897 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1899 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1901 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
1902 error("socket: %.100s", strerror(errno));
1905 debug("x11_create_display_inet: Socket family %d not supported",
1910 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1911 debug("bind port %d: %.100s", port, strerror(errno));
1912 shutdown(sock, SHUT_RDWR);
1918 for (n = 0; n < num_socks; n++) {
1919 shutdown(socks[n], SHUT_RDWR);
1925 socks[num_socks++] = sock;
1926 #ifndef DONT_TRY_OTHER_AF
1927 if (num_socks == NUM_SOCKS)
1933 freeaddrinfo(aitop);
1937 if (display_number >= MAX_DISPLAYS) {
1938 error("Failed to allocate internet-domain X11 display socket.");
1941 /* Start listening for connections on the socket. */
1942 for (n = 0; n < num_socks; n++) {
1944 if (listen(sock, 5) < 0) {
1945 error("listen: %.100s", strerror(errno));
1946 shutdown(sock, SHUT_RDWR);
1952 /* Set up a suitable value for the DISPLAY variable. */
1953 if (gethostname(hostname, sizeof(hostname)) < 0)
1954 fatal("gethostname: %.100s", strerror(errno));
1956 #ifdef IPADDR_IN_DISPLAY
1958 * HPUX detects the local hostname in the DISPLAY variable and tries
1959 * to set up a shared memory connection to the server, which it
1960 * incorrectly supposes to be local.
1962 * The workaround - as used in later $$H and other programs - is
1963 * is to set display to the host's IP address.
1967 struct in_addr my_addr;
1969 he = gethostbyname(hostname);
1971 error("[X11-broken-fwd-hostname-workaround] Could not get "
1972 "IP address for hostname %s.", hostname);
1974 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
1975 "Could not get IP address for hostname %s.", hostname);
1977 shutdown(sock, SHUT_RDWR);
1983 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
1985 /* Set DISPLAY to <ip address>:screen.display */
1986 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
1987 display_number, screen_number);
1989 #else /* IPADDR_IN_DISPLAY */
1990 /* Just set DISPLAY to hostname:screen.display */
1991 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1992 display_number, screen_number);
1993 #endif /* IPADDR_IN_DISPLAY */
1995 /* Allocate a channel for each socket. */
1996 for (n = 0; n < num_socks; n++) {
1998 (void) channel_new("x11 listener",
1999 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2000 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2001 0, xstrdup("X11 inet listener"), 1);
2004 /* Return a suitable value for the DISPLAY environment variable. */
2005 return xstrdup(display);
2009 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2014 connect_local_xsocket(u_int dnr)
2016 static const char *const x_sockets[] = {
2018 "/var/X/.X11-unix/X" "%u",
2019 "/usr/spool/sockets/X11/" "%u",
2023 struct sockaddr_un addr;
2024 const char *const * path;
2026 for (path = x_sockets; *path; ++path) {
2027 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2029 error("socket: %.100s", strerror(errno));
2030 memset(&addr, 0, sizeof(addr));
2031 addr.sun_family = AF_UNIX;
2032 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2033 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2037 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2042 x11_connect_display(void)
2044 int display_number, sock = 0;
2045 const char *display;
2046 char buf[1024], *cp;
2047 struct addrinfo hints, *ai, *aitop;
2048 char strport[NI_MAXSERV];
2051 /* Try to open a socket for the local X server. */
2052 display = getenv("DISPLAY");
2054 error("DISPLAY not set.");
2058 * Now we decode the value of the DISPLAY variable and make a
2059 * connection to the real X server.
2063 * Check if it is a unix domain socket. Unix domain displays are in
2064 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2066 if (strncmp(display, "unix:", 5) == 0 ||
2067 display[0] == ':') {
2068 /* Connect to the unix domain socket. */
2069 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2070 error("Could not parse display number from DISPLAY: %.100s",
2074 /* Create a socket. */
2075 sock = connect_local_xsocket(display_number);
2079 /* OK, we now have a connection to the display. */
2083 * Connect to an inet socket. The DISPLAY value is supposedly
2084 * hostname:d[.s], where hostname may also be numeric IP address.
2086 strncpy(buf, display, sizeof(buf));
2087 buf[sizeof(buf) - 1] = 0;
2088 cp = strchr(buf, ':');
2090 error("Could not find ':' in DISPLAY: %.100s", display);
2094 /* buf now contains the host name. But first we parse the display number. */
2095 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2096 error("Could not parse display number from DISPLAY: %.100s",
2101 /* Look up the host address */
2102 memset(&hints, 0, sizeof(hints));
2103 hints.ai_family = IPv4or6;
2104 hints.ai_socktype = SOCK_STREAM;
2105 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2106 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2107 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2110 for (ai = aitop; ai; ai = ai->ai_next) {
2111 /* Create a socket. */
2112 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2114 debug("socket: %.100s", strerror(errno));
2117 /* Connect it to the display. */
2118 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2119 debug("connect %.100s port %d: %.100s", buf,
2120 6000 + display_number, strerror(errno));
2127 freeaddrinfo(aitop);
2129 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2137 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2138 * the remote channel number. We should do whatever we want, and respond
2139 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2143 x11_input_open(int type, int plen, void *ctxt)
2145 int remote_channel, sock = 0, newch;
2149 /* Get remote channel number. */
2150 remote_channel = packet_get_int();
2152 /* Get remote originator name. */
2153 if (have_hostname_in_open) {
2154 remote_host = packet_get_string(&remote_len);
2157 remote_host = xstrdup("unknown (remote did not supply name)");
2161 debug("Received X11 open request.");
2162 packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
2164 /* Obtain a connection to the real X display. */
2165 sock = x11_connect_display();
2167 /* Send refusal to the remote host. */
2168 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2169 packet_put_int(remote_channel);
2172 /* Allocate a channel for this connection. */
2173 newch = channel_allocate(
2174 (x11_saved_proto == NULL) ?
2175 SSH_CHANNEL_OPEN : SSH_CHANNEL_X11_OPEN,
2177 channels[newch].remote_id = remote_channel;
2179 /* Send a confirmation to the remote host. */
2180 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2181 packet_put_int(remote_channel);
2182 packet_put_int(newch);
2187 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2189 deny_input_open(int type, int plen, void *ctxt)
2191 int rchan = packet_get_int();
2193 case SSH_SMSG_AGENT_OPEN:
2194 error("Warning: ssh server tried agent forwarding.");
2196 case SSH_SMSG_X11_OPEN:
2197 error("Warning: ssh server tried X11 forwarding.");
2200 error("deny_input_open: type %d plen %d", type, plen);
2203 error("Warning: this is probably a break in attempt by a malicious server.");
2204 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2205 packet_put_int(rchan);
2210 * Requests forwarding of X11 connections, generates fake authentication
2211 * data, and enables authentication spoofing.
2215 x11_request_forwarding_with_spoofing(int client_session_id,
2216 const char *proto, const char *data)
2218 u_int data_len = (u_int) strlen(data) / 2;
2225 cp = getenv("DISPLAY");
2227 cp = strchr(cp, ':');
2229 cp = strchr(cp, '.');
2231 screen_number = atoi(cp + 1);
2235 /* Save protocol name. */
2236 x11_saved_proto = xstrdup(proto);
2239 * Extract real authentication data and generate fake data of the
2242 x11_saved_data = xmalloc(data_len);
2243 x11_fake_data = xmalloc(data_len);
2244 for (i = 0; i < data_len; i++) {
2245 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2246 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2248 rand = arc4random();
2249 x11_saved_data[i] = value;
2250 x11_fake_data[i] = rand & 0xff;
2253 x11_saved_data_len = data_len;
2254 x11_fake_data_len = data_len;
2256 /* Convert the fake data into hex. */
2257 new_data = xmalloc(2 * data_len + 1);
2258 for (i = 0; i < data_len; i++)
2259 sprintf(new_data + 2 * i, "%02x", (u_char) x11_fake_data[i]);
2261 /* Send the request packet. */
2263 channel_request_start(client_session_id, "x11-req", 0);
2264 packet_put_char(0); /* XXX bool single connection */
2266 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2268 packet_put_cstring(proto);
2269 packet_put_cstring(new_data);
2270 packet_put_int(screen_number);
2272 packet_write_wait();
2276 /* Sends a message to the server to request authentication fd forwarding. */
2279 auth_request_forwarding()
2281 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2283 packet_write_wait();
2287 * Returns the name of the forwarded authentication socket. Returns NULL if
2288 * there is no forwarded authentication socket. The returned value points to
2293 auth_get_socket_name()
2295 return channel_forwarded_auth_socket_name;
2298 /* removes the agent forwarding socket */
2301 cleanup_socket(void)
2303 unlink(channel_forwarded_auth_socket_name);
2304 rmdir(channel_forwarded_auth_socket_dir);
2308 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2309 * This starts forwarding authentication requests.
2313 auth_input_request_forwarding(struct passwd * pw)
2316 struct sockaddr_un sunaddr;
2318 if (auth_get_socket_name() != NULL)
2319 fatal("Protocol error: authentication forwarding requested twice.");
2321 /* Temporarily drop privileged uid for mkdir/bind. */
2322 temporarily_use_uid(pw->pw_uid);
2324 /* Allocate a buffer for the socket name, and format the name. */
2325 channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
2326 channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
2327 strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
2329 /* Create private directory for socket */
2330 if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL) {
2331 packet_send_debug("Agent forwarding disabled: mkdtemp() failed: %.100s",
2334 xfree(channel_forwarded_auth_socket_name);
2335 xfree(channel_forwarded_auth_socket_dir);
2336 channel_forwarded_auth_socket_name = NULL;
2337 channel_forwarded_auth_socket_dir = NULL;
2340 snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
2341 channel_forwarded_auth_socket_dir, (int) getpid());
2343 if (atexit(cleanup_socket) < 0) {
2346 packet_disconnect("socket: %.100s", strerror(saved));
2348 /* Create the socket. */
2349 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2351 packet_disconnect("socket: %.100s", strerror(errno));
2353 /* Bind it to the name. */
2354 memset(&sunaddr, 0, sizeof(sunaddr));
2355 sunaddr.sun_family = AF_UNIX;
2356 strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
2357 sizeof(sunaddr.sun_path));
2359 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2360 packet_disconnect("bind: %.100s", strerror(errno));
2362 /* Restore the privileged uid. */
2365 /* Start listening on the socket. */
2366 if (listen(sock, 5) < 0)
2367 packet_disconnect("listen: %.100s", strerror(errno));
2369 /* Allocate a channel for the authentication agent socket. */
2370 newch = channel_new("auth socket",
2371 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2372 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2373 0, xstrdup("auth socket"), 1);
2375 strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
2376 sizeof(channels[newch].path));
2380 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2383 auth_input_open_request(int type, int plen, void *ctxt)
2385 int remch, sock, newch;
2388 packet_integrity_check(plen, 4, type);
2390 /* Read the remote channel number from the message. */
2391 remch = packet_get_int();
2394 * Get a connection to the local authentication agent (this may again
2397 sock = ssh_get_authentication_socket();
2400 * If we could not connect the agent, send an error message back to
2401 * the server. This should never happen unless the agent dies,
2402 * because authentication forwarding is only enabled if we have an
2406 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2407 packet_put_int(remch);
2411 debug("Forwarding authentication connection.");
2414 * Dummy host name. This will be freed when the channel is freed; it
2415 * will still be valid in the packet_put_string below since the
2416 * channel cannot yet be freed at that point.
2418 dummyname = xstrdup("authentication agent connection");
2420 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
2421 channels[newch].remote_id = remch;
2423 /* Send a confirmation to the remote host. */
2424 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2425 packet_put_int(remch);
2426 packet_put_int(newch);
2431 channel_start_open(int id)
2433 Channel *c = channel_lookup(id);
2435 log("channel_open: %d: bad id", id);
2438 debug("send channel open %d", id);
2439 packet_start(SSH2_MSG_CHANNEL_OPEN);
2440 packet_put_cstring(c->ctype);
2441 packet_put_int(c->self);
2442 packet_put_int(c->local_window);
2443 packet_put_int(c->local_maxpacket);
2446 channel_open(int id)
2449 channel_start_open(id);
2453 channel_request(int id, char *service, int wantconfirm)
2455 channel_request_start(id, service, wantconfirm);
2457 debug("channel request %d: %s", id, service) ;
2460 channel_request_start(int id, char *service, int wantconfirm)
2462 Channel *c = channel_lookup(id);
2464 log("channel_request: %d: bad id", id);
2467 packet_start(SSH2_MSG_CHANNEL_REQUEST);
2468 packet_put_int(c->remote_id);
2469 packet_put_cstring(service);
2470 packet_put_char(wantconfirm);
2473 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
2475 Channel *c = channel_lookup(id);
2477 log("channel_register_callback: %d: bad id", id);
2480 c->cb_event = mtype;
2485 channel_register_cleanup(int id, channel_callback_fn *fn)
2487 Channel *c = channel_lookup(id);
2489 log("channel_register_cleanup: %d: bad id", id);
2492 c->dettach_user = fn;
2495 channel_cancel_cleanup(int id)
2497 Channel *c = channel_lookup(id);
2499 log("channel_cancel_cleanup: %d: bad id", id);
2502 c->dettach_user = NULL;
2505 channel_register_filter(int id, channel_filter_fn *fn)
2507 Channel *c = channel_lookup(id);
2509 log("channel_register_filter: %d: bad id", id);
2512 c->input_filter = fn;
2516 channel_set_fds(int id, int rfd, int wfd, int efd,
2517 int extusage, int nonblock)
2519 Channel *c = channel_lookup(id);
2520 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
2521 fatal("channel_activate for non-larval channel %d.", id);
2522 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
2523 c->type = SSH_CHANNEL_OPEN;
2524 /* XXX window size? */
2525 c->local_window = c->local_window_max = c->local_maxpacket * 2;
2526 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2527 packet_put_int(c->remote_id);
2528 packet_put_int(c->local_window);