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 1.73 2000/11/06 23:04:55 markus Exp $");
59 #include <openssl/rsa.h>
60 #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_value = 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 unsigned 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 unsigned 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 /* Sets specific protocol options. */
136 channel_set_options(int hostname_in_open)
138 have_hostname_in_open = hostname_in_open;
142 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
143 * called by the server, because the user could connect to any port anyway,
144 * and the server has no way to know but to trust the client anyway.
148 channel_permit_all_opens()
150 all_opens_permitted = 1;
153 /* lookup channel by id */
156 channel_lookup(int id)
159 if (id < 0 || id > channels_alloc) {
160 log("channel_lookup: %d: bad id", id);
164 if (c->type == SSH_CHANNEL_FREE) {
165 log("channel_lookup: %d: bad id: channel free", id);
172 * Register filedescriptors for a channel, used when allocating a channel or
173 * when the channel consumer/producer is ready, e.g. shell exec'd
177 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
178 int extusage, int nonblock)
180 /* Update the maximum file descriptor value. */
181 if (rfd > channel_max_fd_value)
182 channel_max_fd_value = rfd;
183 if (wfd > channel_max_fd_value)
184 channel_max_fd_value = wfd;
185 if (efd > channel_max_fd_value)
186 channel_max_fd_value = efd;
187 /* XXX set close-on-exec -markus */
191 c->sock = (rfd == wfd) ? rfd : -1;
193 c->extended_usage = extusage;
195 /* enable nonblocking mode */
207 * Allocate a new channel object and set its type and socket. This will cause
208 * remote_name to be freed.
212 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
213 int window, int maxpack, int extusage, char *remote_name, int nonblock)
218 /* Do initial allocation if this is the first call. */
219 if (channels_alloc == 0) {
222 channels = xmalloc(channels_alloc * sizeof(Channel));
223 for (i = 0; i < channels_alloc; i++)
224 channels[i].type = SSH_CHANNEL_FREE;
226 * Kludge: arrange a call to channel_stop_listening if we
227 * terminate with fatal().
229 fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
231 /* Try to find a free slot where to put the new channel. */
232 for (found = -1, i = 0; i < channels_alloc; i++)
233 if (channels[i].type == SSH_CHANNEL_FREE) {
234 /* Found a free slot. */
239 /* There are no free slots. Take last+1 slot and expand the array. */
240 found = channels_alloc;
241 channels_alloc += 10;
242 debug2("channel: expanding %d", channels_alloc);
243 channels = xrealloc(channels, channels_alloc * sizeof(Channel));
244 for (i = found; i < channels_alloc; i++)
245 channels[i].type = SSH_CHANNEL_FREE;
247 /* Initialize and return new channel number. */
248 c = &channels[found];
249 buffer_init(&c->input);
250 buffer_init(&c->output);
251 buffer_init(&c->extended);
252 chan_init_iostates(c);
253 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
257 c->local_window = window;
258 c->local_window_max = window;
259 c->local_consumed = 0;
260 c->local_maxpacket = maxpack;
262 c->remote_name = remote_name;
263 c->remote_window = 0;
264 c->remote_maxpacket = 0;
268 c->dettach_user = NULL;
269 c->input_filter = NULL;
270 debug("channel %d: new [%s]", found, remote_name);
273 /* old interface XXX */
275 channel_allocate(int type, int sock, char *remote_name)
277 return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name, 1);
281 /* Close all channel fd/socket. */
284 channel_close_fds(Channel *c)
304 /* Free the channel and close its fd/socket. */
309 Channel *c = channel_lookup(id);
311 packet_disconnect("channel free: bad local channel %d", id);
312 debug("channel_free: channel %d: status: %s", id, channel_open_message());
313 if (c->dettach_user != NULL) {
314 debug("channel_free: channel %d: dettaching channel user", id);
315 c->dettach_user(c->self, NULL);
318 shutdown(c->sock, SHUT_RDWR);
319 channel_close_fds(c);
320 buffer_free(&c->input);
321 buffer_free(&c->output);
322 buffer_free(&c->extended);
323 c->type = SSH_CHANNEL_FREE;
324 if (c->remote_name) {
325 xfree(c->remote_name);
326 c->remote_name = NULL;
331 * 'channel_pre*' are called just before select() to add any bits relevant to
332 * channels in the select bitmasks.
335 * 'channel_post*': perform any appropriate operations for channels which
336 * have events pending.
338 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
339 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
340 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
343 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
345 FD_SET(c->sock, readset);
349 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
351 if (buffer_len(&c->input) < packet_get_maxsize())
352 FD_SET(c->sock, readset);
353 if (buffer_len(&c->output) > 0)
354 FD_SET(c->sock, writeset);
358 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
360 /* test whether sockets are 'alive' for read/write */
361 if (c->istate == CHAN_INPUT_OPEN)
362 if (buffer_len(&c->input) < packet_get_maxsize())
363 FD_SET(c->sock, readset);
364 if (c->ostate == CHAN_OUTPUT_OPEN ||
365 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
366 if (buffer_len(&c->output) > 0) {
367 FD_SET(c->sock, writeset);
368 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
375 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
377 if (c->istate == CHAN_INPUT_OPEN &&
378 c->remote_window > 0 &&
379 buffer_len(&c->input) < c->remote_window)
380 FD_SET(c->rfd, readset);
381 if (c->ostate == CHAN_OUTPUT_OPEN ||
382 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
383 if (buffer_len(&c->output) > 0) {
384 FD_SET(c->wfd, writeset);
385 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
389 /** XXX check close conditions, too */
391 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
392 buffer_len(&c->extended) > 0)
393 FD_SET(c->efd, writeset);
394 else if (c->extended_usage == CHAN_EXTENDED_READ &&
395 buffer_len(&c->extended) < c->remote_window)
396 FD_SET(c->efd, readset);
401 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
403 if (buffer_len(&c->input) == 0) {
404 packet_start(SSH_MSG_CHANNEL_CLOSE);
405 packet_put_int(c->remote_id);
407 c->type = SSH_CHANNEL_CLOSED;
408 debug("Closing channel %d after input drain.", c->self);
413 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
415 if (buffer_len(&c->output) == 0)
416 channel_free(c->self);
418 FD_SET(c->sock, writeset);
422 * This is a special state for X11 authentication spoofing. An opened X11
423 * connection (when authentication spoofing is being done) remains in this
424 * state until the first packet has been completely read. The authentication
425 * data in that packet is then substituted by the real data if it matches the
426 * fake data, and the channel is put into normal mode.
427 * XXX All this happens at the client side.
430 x11_open_helper(Channel *c)
433 unsigned int proto_len, data_len;
435 /* Check if the fixed size part of the packet is in buffer. */
436 if (buffer_len(&c->output) < 12)
439 /* Parse the lengths of variable-length fields. */
440 ucp = (unsigned char *) buffer_ptr(&c->output);
441 if (ucp[0] == 0x42) { /* Byte order MSB first. */
442 proto_len = 256 * ucp[6] + ucp[7];
443 data_len = 256 * ucp[8] + ucp[9];
444 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
445 proto_len = ucp[6] + 256 * ucp[7];
446 data_len = ucp[8] + 256 * ucp[9];
448 debug("Initial X11 packet contains bad byte order byte: 0x%x",
453 /* Check if the whole packet is in buffer. */
454 if (buffer_len(&c->output) <
455 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
458 /* Check if authentication protocol matches. */
459 if (proto_len != strlen(x11_saved_proto) ||
460 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
461 debug("X11 connection uses different authentication protocol.");
464 /* Check if authentication data matches our fake data. */
465 if (data_len != x11_fake_data_len ||
466 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
467 x11_fake_data, x11_fake_data_len) != 0) {
468 debug("X11 auth data does not match fake data.");
471 /* Check fake data length */
472 if (x11_fake_data_len != x11_saved_data_len) {
473 error("X11 fake_data_len %d != saved_data_len %d",
474 x11_fake_data_len, x11_saved_data_len);
478 * Received authentication protocol and data match
479 * our fake data. Substitute the fake data with real
482 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
483 x11_saved_data, x11_saved_data_len);
488 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
490 int ret = x11_open_helper(c);
492 /* Start normal processing for the channel. */
493 c->type = SSH_CHANNEL_OPEN;
494 channel_pre_open_13(c, readset, writeset);
495 } else if (ret == -1) {
497 * We have received an X11 connection that has bad
498 * authentication information.
500 log("X11 connection rejected because of wrong authentication.\r\n");
501 buffer_clear(&c->input);
502 buffer_clear(&c->output);
505 c->type = SSH_CHANNEL_CLOSED;
506 packet_start(SSH_MSG_CHANNEL_CLOSE);
507 packet_put_int(c->remote_id);
513 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
515 int ret = x11_open_helper(c);
517 c->type = SSH_CHANNEL_OPEN;
519 channel_pre_open_20(c, readset, writeset);
521 channel_pre_open_15(c, readset, writeset);
522 } else if (ret == -1) {
523 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
524 chan_read_failed(c); /** force close? */
525 chan_write_failed(c);
526 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
530 /* This is our fake X11 server socket. */
532 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
534 struct sockaddr addr;
537 char buf[16384], *remote_hostname;
540 if (FD_ISSET(c->sock, readset)) {
541 debug("X11 connection requested.");
542 addrlen = sizeof(addr);
543 newsock = accept(c->sock, &addr, &addrlen);
545 error("accept: %.100s", strerror(errno));
548 remote_hostname = get_remote_hostname(newsock);
549 remote_port = get_peer_port(newsock);
550 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
551 remote_hostname, remote_port);
553 newch = channel_new("x11",
554 SSH_CHANNEL_OPENING, newsock, newsock, -1,
555 c->local_window_max, c->local_maxpacket,
558 packet_start(SSH2_MSG_CHANNEL_OPEN);
559 packet_put_cstring("x11");
560 packet_put_int(newch);
561 packet_put_int(c->local_window_max);
562 packet_put_int(c->local_maxpacket);
563 /* originator host and port */
564 packet_put_cstring(remote_hostname);
565 if (datafellows & SSH_BUG_X11FWD) {
566 debug("ssh2 x11 bug compat mode");
568 packet_put_int(remote_port);
572 packet_start(SSH_SMSG_X11_OPEN);
573 packet_put_int(newch);
574 if (have_hostname_in_open)
575 packet_put_string(buf, strlen(buf));
578 xfree(remote_hostname);
583 * This socket is listening for connections to a forwarded TCP/IP port.
586 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
588 struct sockaddr addr;
591 char buf[1024], *remote_hostname, *rtype;
594 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
595 "forwarded-tcpip" : "direct-tcpip";
597 if (FD_ISSET(c->sock, readset)) {
598 debug("Connection to port %d forwarding "
599 "to %.100s port %d requested.",
600 c->listening_port, c->path, c->host_port);
601 addrlen = sizeof(addr);
602 newsock = accept(c->sock, &addr, &addrlen);
604 error("accept: %.100s", strerror(errno));
607 remote_hostname = get_remote_hostname(newsock);
608 remote_port = get_peer_port(newsock);
609 snprintf(buf, sizeof buf,
610 "listen port %d for %.100s port %d, "
611 "connect from %.200s port %d",
612 c->listening_port, c->path, c->host_port,
613 remote_hostname, remote_port);
615 newch = channel_new(rtype,
616 SSH_CHANNEL_OPENING, newsock, newsock, -1,
617 c->local_window_max, c->local_maxpacket,
620 packet_start(SSH2_MSG_CHANNEL_OPEN);
621 packet_put_cstring(rtype);
622 packet_put_int(newch);
623 packet_put_int(c->local_window_max);
624 packet_put_int(c->local_maxpacket);
625 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
626 /* listen address, port */
627 packet_put_string(c->path, strlen(c->path));
628 packet_put_int(c->listening_port);
630 /* target host, port */
631 packet_put_string(c->path, strlen(c->path));
632 packet_put_int(c->host_port);
634 /* originator host and port */
635 packet_put_cstring(remote_hostname);
636 packet_put_int(remote_port);
639 packet_start(SSH_MSG_PORT_OPEN);
640 packet_put_int(newch);
641 packet_put_string(c->path, strlen(c->path));
642 packet_put_int(c->host_port);
643 if (have_hostname_in_open) {
644 packet_put_string(buf, strlen(buf));
648 xfree(remote_hostname);
653 * This is the authentication agent socket listening for connections from
657 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
659 struct sockaddr addr;
663 if (FD_ISSET(c->sock, readset)) {
664 addrlen = sizeof(addr);
665 newsock = accept(c->sock, &addr, &addrlen);
667 error("accept from auth socket: %.100s", strerror(errno));
670 newch = channel_new("accepted auth socket",
671 SSH_CHANNEL_OPENING, newsock, newsock, -1,
672 c->local_window_max, c->local_maxpacket,
673 0, xstrdup("accepted auth socket"), 1);
675 packet_start(SSH2_MSG_CHANNEL_OPEN);
676 packet_put_cstring("auth-agent@openssh.com");
677 packet_put_int(newch);
678 packet_put_int(c->local_window_max);
679 packet_put_int(c->local_maxpacket);
681 packet_start(SSH_SMSG_AGENT_OPEN);
682 packet_put_int(newch);
689 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
695 FD_ISSET(c->rfd, readset)) {
696 len = read(c->rfd, buf, sizeof(buf));
697 if (len < 0 && (errno == EINTR || errno == EAGAIN))
700 debug("channel %d: read<=0 rfd %d len %d",
701 c->self, c->rfd, len);
703 buffer_consume(&c->output, buffer_len(&c->output));
704 c->type = SSH_CHANNEL_INPUT_DRAINING;
705 debug("Channel %d status set to input draining.", c->self);
711 if(c->input_filter != NULL) {
712 if (c->input_filter(c, buf, len) == -1) {
713 debug("filter stops channel %d", c->self);
717 buffer_append(&c->input, buf, len);
723 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
727 /* Send buffered output data to the socket. */
729 FD_ISSET(c->wfd, writeset) &&
730 buffer_len(&c->output) > 0) {
731 len = write(c->wfd, buffer_ptr(&c->output),
732 buffer_len(&c->output));
733 if (len < 0 && (errno == EINTR || errno == EAGAIN))
737 buffer_consume(&c->output, buffer_len(&c->output));
738 debug("Channel %d status set to input draining.", c->self);
739 c->type = SSH_CHANNEL_INPUT_DRAINING;
741 chan_write_failed(c);
745 buffer_consume(&c->output, len);
746 if (compat20 && len > 0) {
747 c->local_consumed += len;
753 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
758 /** XXX handle drain efd, too */
760 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
761 FD_ISSET(c->efd, writeset) &&
762 buffer_len(&c->extended) > 0) {
763 len = write(c->efd, buffer_ptr(&c->extended),
764 buffer_len(&c->extended));
765 debug2("channel %d: written %d to efd %d",
766 c->self, len, c->efd);
768 buffer_consume(&c->extended, len);
769 c->local_consumed += len;
771 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
772 FD_ISSET(c->efd, readset)) {
773 len = read(c->efd, buf, sizeof(buf));
774 debug2("channel %d: read %d from efd %d",
775 c->self, len, c->efd);
777 debug("channel %d: closing efd %d",
782 buffer_append(&c->extended, buf, len);
788 channel_check_window(Channel *c, fd_set * readset, fd_set * writeset)
790 if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
791 c->local_window < c->local_window_max/2 &&
792 c->local_consumed > 0) {
793 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
794 packet_put_int(c->remote_id);
795 packet_put_int(c->local_consumed);
797 debug2("channel %d: window %d sent adjust %d",
798 c->self, c->local_window,
800 c->local_window += c->local_consumed;
801 c->local_consumed = 0;
807 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
809 channel_handle_rfd(c, readset, writeset);
810 channel_handle_wfd(c, readset, writeset);
814 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
816 channel_handle_rfd(c, readset, writeset);
817 channel_handle_wfd(c, readset, writeset);
818 channel_handle_efd(c, readset, writeset);
819 channel_check_window(c, readset, writeset);
823 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
826 /* Send buffered output data to the socket. */
827 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
828 len = write(c->sock, buffer_ptr(&c->output),
829 buffer_len(&c->output));
831 buffer_consume(&c->output, buffer_len(&c->output));
833 buffer_consume(&c->output, len);
838 channel_handler_init_20(void)
840 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
841 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
842 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
843 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
844 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
845 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
847 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
848 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
849 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
850 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
851 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
855 channel_handler_init_13(void)
857 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
858 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
859 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
860 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
861 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
862 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
863 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
865 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
866 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
867 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
868 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
869 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
873 channel_handler_init_15(void)
875 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
876 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
877 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
878 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
879 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
881 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
882 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
883 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
884 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
888 channel_handler_init(void)
891 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
892 channel_pre[i] = NULL;
893 channel_post[i] = NULL;
896 channel_handler_init_20();
898 channel_handler_init_13();
900 channel_handler_init_15();
904 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
906 static int did_init = 0;
911 channel_handler_init();
914 for (i = 0; i < channels_alloc; i++) {
916 if (c->type == SSH_CHANNEL_FREE)
918 if (ftab[c->type] == NULL)
920 (*ftab[c->type])(c, readset, writeset);
921 chan_delete_if_full_closed(c);
926 channel_prepare_select(fd_set * readset, fd_set * writeset)
928 channel_handler(channel_pre, readset, writeset);
932 channel_after_select(fd_set * readset, fd_set * writeset)
934 channel_handler(channel_post, readset, writeset);
937 /* If there is data to send to the connection, send some of it now. */
940 channel_output_poll()
945 for (i = 0; i < channels_alloc; i++) {
948 /* We are only interested in channels that can have buffered incoming data. */
950 if (c->type != SSH_CHANNEL_OPEN &&
951 c->type != SSH_CHANNEL_INPUT_DRAINING)
954 if (c->type != SSH_CHANNEL_OPEN)
956 if (c->istate != CHAN_INPUT_OPEN &&
957 c->istate != CHAN_INPUT_WAIT_DRAIN)
961 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
962 debug("channel: %d: no data after CLOSE", c->self);
966 /* Get the amount of buffered data for this channel. */
967 len = buffer_len(&c->input);
969 /* Send some data for the other side over the secure connection. */
971 if (len > c->remote_window)
972 len = c->remote_window;
973 if (len > c->remote_maxpacket)
974 len = c->remote_maxpacket;
976 if (packet_is_interactive()) {
980 /* Keep the packets at reasonable size. */
981 if (len > packet_get_maxsize()/2)
982 len = packet_get_maxsize()/2;
986 packet_start(compat20 ?
987 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
988 packet_put_int(c->remote_id);
989 packet_put_string(buffer_ptr(&c->input), len);
991 buffer_consume(&c->input, len);
992 c->remote_window -= len;
994 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
996 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
998 * input-buffer is empty and read-socket shutdown:
999 * tell peer, that we will not send more data: send IEOF
1003 /* Send extended data, i.e. stderr */
1005 c->remote_window > 0 &&
1006 (len = buffer_len(&c->extended)) > 0 &&
1007 c->extended_usage == CHAN_EXTENDED_READ) {
1008 if (len > c->remote_window)
1009 len = c->remote_window;
1010 if (len > c->remote_maxpacket)
1011 len = c->remote_maxpacket;
1012 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1013 packet_put_int(c->remote_id);
1014 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1015 packet_put_string(buffer_ptr(&c->extended), len);
1017 buffer_consume(&c->extended, len);
1018 c->remote_window -= len;
1024 * This is called when a packet of type CHANNEL_DATA has just been received.
1025 * The message type has already been consumed, but channel number and data is
1030 channel_input_data(int type, int plen, void *ctxt)
1034 unsigned int data_len;
1037 /* Get the channel number and verify it. */
1038 id = packet_get_int();
1039 c = channel_lookup(id);
1041 packet_disconnect("Received data for nonexistent channel %d.", id);
1043 /* Ignore any data for non-open channels (might happen on close) */
1044 if (c->type != SSH_CHANNEL_OPEN &&
1045 c->type != SSH_CHANNEL_X11_OPEN)
1048 /* same for protocol 1.5 if output end is no longer open */
1049 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1053 data = packet_get_string(&data_len);
1057 if (data_len > c->local_maxpacket) {
1058 log("channel %d: rcvd big packet %d, maxpack %d",
1059 c->self, data_len, c->local_maxpacket);
1061 if (data_len > c->local_window) {
1062 log("channel %d: rcvd too much data %d, win %d",
1063 c->self, data_len, c->local_window);
1067 c->local_window -= data_len;
1069 packet_integrity_check(plen, 4 + 4 + data_len, type);
1071 buffer_append(&c->output, data, data_len);
1075 channel_input_extended_data(int type, int plen, void *ctxt)
1080 unsigned int data_len;
1083 /* Get the channel number and verify it. */
1084 id = packet_get_int();
1085 c = channel_lookup(id);
1088 packet_disconnect("Received extended_data for bad channel %d.", id);
1089 if (c->type != SSH_CHANNEL_OPEN) {
1090 log("channel %d: ext data for non open", id);
1093 tcode = packet_get_int();
1095 c->extended_usage != CHAN_EXTENDED_WRITE ||
1096 tcode != SSH2_EXTENDED_DATA_STDERR) {
1097 log("channel %d: bad ext data", c->self);
1100 data = packet_get_string(&data_len);
1102 if (data_len > c->local_window) {
1103 log("channel %d: rcvd too much extended_data %d, win %d",
1104 c->self, data_len, c->local_window);
1108 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1109 c->local_window -= data_len;
1110 buffer_append(&c->extended, data, data_len);
1116 * Returns true if no channel has too much buffered data, and false if one or
1117 * more channel is overfull.
1121 channel_not_very_much_buffered_data()
1126 for (i = 0; i < channels_alloc; i++) {
1128 if (c->type == SSH_CHANNEL_OPEN) {
1129 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
1130 debug("channel %d: big input buffer %d",
1131 c->self, buffer_len(&c->input));
1134 if (buffer_len(&c->output) > packet_get_maxsize()) {
1135 debug("channel %d: big output buffer %d",
1136 c->self, buffer_len(&c->output));
1145 channel_input_ieof(int type, int plen, void *ctxt)
1150 packet_integrity_check(plen, 4, type);
1152 id = packet_get_int();
1153 c = channel_lookup(id);
1155 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1160 channel_input_close(int type, int plen, void *ctxt)
1165 packet_integrity_check(plen, 4, type);
1167 id = packet_get_int();
1168 c = channel_lookup(id);
1170 packet_disconnect("Received close for nonexistent channel %d.", id);
1173 * Send a confirmation that we have closed the channel and no more
1174 * data is coming for it.
1176 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1177 packet_put_int(c->remote_id);
1181 * If the channel is in closed state, we have sent a close request,
1182 * and the other side will eventually respond with a confirmation.
1183 * Thus, we cannot free the channel here, because then there would be
1184 * no-one to receive the confirmation. The channel gets freed when
1185 * the confirmation arrives.
1187 if (c->type != SSH_CHANNEL_CLOSED) {
1189 * Not a closed channel - mark it as draining, which will
1190 * cause it to be freed later.
1192 buffer_consume(&c->input, buffer_len(&c->input));
1193 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1197 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1199 channel_input_oclose(int type, int plen, void *ctxt)
1201 int id = packet_get_int();
1202 Channel *c = channel_lookup(id);
1203 packet_integrity_check(plen, 4, type);
1205 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1206 chan_rcvd_oclose(c);
1210 channel_input_close_confirmation(int type, int plen, void *ctxt)
1212 int id = packet_get_int();
1213 Channel *c = channel_lookup(id);
1217 packet_disconnect("Received close confirmation for "
1218 "out-of-range channel %d.", id);
1219 if (c->type != SSH_CHANNEL_CLOSED)
1220 packet_disconnect("Received close confirmation for "
1221 "non-closed channel %d (type %d).", id, c->type);
1222 channel_free(c->self);
1226 channel_input_open_confirmation(int type, int plen, void *ctxt)
1232 packet_integrity_check(plen, 4 + 4, type);
1234 id = packet_get_int();
1235 c = channel_lookup(id);
1237 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1238 packet_disconnect("Received open confirmation for "
1239 "non-opening channel %d.", id);
1240 remote_id = packet_get_int();
1241 /* Record the remote channel number and mark that the channel is now open. */
1242 c->remote_id = remote_id;
1243 c->type = SSH_CHANNEL_OPEN;
1246 c->remote_window = packet_get_int();
1247 c->remote_maxpacket = packet_get_int();
1249 if (c->cb_fn != NULL && c->cb_event == type) {
1250 debug2("callback start");
1251 c->cb_fn(c->self, c->cb_arg);
1252 debug2("callback done");
1254 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1255 c->remote_window, c->remote_maxpacket);
1260 channel_input_open_failure(int type, int plen, void *ctxt)
1266 packet_integrity_check(plen, 4, type);
1268 id = packet_get_int();
1269 c = channel_lookup(id);
1271 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1272 packet_disconnect("Received open failure for "
1273 "non-opening channel %d.", id);
1275 int reason = packet_get_int();
1276 char *msg = packet_get_string(NULL);
1277 char *lang = packet_get_string(NULL);
1278 log("channel_open_failure: %d: reason %d: %s", id, reason, msg);
1283 /* Free the channel. This will also close the socket. */
1288 channel_input_channel_request(int type, int plen, void *ctxt)
1293 id = packet_get_int();
1294 c = channel_lookup(id);
1297 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1298 packet_disconnect("Received request for "
1299 "non-open channel %d.", id);
1300 if (c->cb_fn != NULL && c->cb_event == type) {
1301 debug2("callback start");
1302 c->cb_fn(c->self, c->cb_arg);
1303 debug2("callback done");
1305 char *service = packet_get_string(NULL);
1306 debug("channel: %d rcvd request for %s", c->self, service);
1307 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1313 channel_input_window_adjust(int type, int plen, void *ctxt)
1321 /* Get the channel number and verify it. */
1322 id = packet_get_int();
1323 c = channel_lookup(id);
1325 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1326 log("Received window adjust for "
1327 "non-open channel %d.", id);
1330 adjust = packet_get_int();
1332 debug2("channel %d: rcvd adjust %d", id, adjust);
1333 c->remote_window += adjust;
1337 * Stops listening for channels, and removes any unix domain sockets that we
1342 channel_stop_listening()
1345 for (i = 0; i < channels_alloc; i++) {
1346 switch (channels[i].type) {
1347 case SSH_CHANNEL_AUTH_SOCKET:
1348 close(channels[i].sock);
1349 unlink(channels[i].path);
1352 case SSH_CHANNEL_PORT_LISTENER:
1353 case SSH_CHANNEL_RPORT_LISTENER:
1354 case SSH_CHANNEL_X11_LISTENER:
1355 close(channels[i].sock);
1365 * Closes the sockets/fds of all channels. This is used to close extra file
1366 * descriptors after a fork.
1373 for (i = 0; i < channels_alloc; i++)
1374 if (channels[i].type != SSH_CHANNEL_FREE)
1375 channel_close_fds(&channels[i]);
1378 /* Returns the maximum file descriptor number used by the channels. */
1383 return channel_max_fd_value;
1386 /* Returns true if any channel is still open. */
1389 channel_still_open()
1392 for (i = 0; i < channels_alloc; i++)
1393 switch (channels[i].type) {
1394 case SSH_CHANNEL_FREE:
1395 case SSH_CHANNEL_X11_LISTENER:
1396 case SSH_CHANNEL_PORT_LISTENER:
1397 case SSH_CHANNEL_RPORT_LISTENER:
1398 case SSH_CHANNEL_CLOSED:
1399 case SSH_CHANNEL_AUTH_SOCKET:
1401 case SSH_CHANNEL_LARVAL:
1403 fatal("cannot happen: SSH_CHANNEL_LARVAL");
1405 case SSH_CHANNEL_OPENING:
1406 case SSH_CHANNEL_OPEN:
1407 case SSH_CHANNEL_X11_OPEN:
1409 case SSH_CHANNEL_INPUT_DRAINING:
1410 case SSH_CHANNEL_OUTPUT_DRAINING:
1412 fatal("cannot happen: OUT_DRAIN");
1415 fatal("channel_still_open: bad channel type %d", channels[i].type);
1422 * Returns a message describing the currently open forwarded connections,
1423 * suitable for sending to the client. The message contains crlf pairs for
1428 channel_open_message()
1434 buffer_init(&buffer);
1435 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
1436 buffer_append(&buffer, buf, strlen(buf));
1437 for (i = 0; i < channels_alloc; i++) {
1438 Channel *c = &channels[i];
1440 case SSH_CHANNEL_FREE:
1441 case SSH_CHANNEL_X11_LISTENER:
1442 case SSH_CHANNEL_PORT_LISTENER:
1443 case SSH_CHANNEL_RPORT_LISTENER:
1444 case SSH_CHANNEL_CLOSED:
1445 case SSH_CHANNEL_AUTH_SOCKET:
1447 case SSH_CHANNEL_LARVAL:
1448 case SSH_CHANNEL_OPENING:
1449 case SSH_CHANNEL_OPEN:
1450 case SSH_CHANNEL_X11_OPEN:
1451 case SSH_CHANNEL_INPUT_DRAINING:
1452 case SSH_CHANNEL_OUTPUT_DRAINING:
1453 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
1454 c->self, c->remote_name,
1455 c->type, c->remote_id,
1456 c->istate, buffer_len(&c->input),
1457 c->ostate, buffer_len(&c->output),
1459 buffer_append(&buffer, buf, strlen(buf));
1462 fatal("channel_open_message: bad channel type %d", c->type);
1466 buffer_append(&buffer, "\0", 1);
1467 cp = xstrdup(buffer_ptr(&buffer));
1468 buffer_free(&buffer);
1473 * Initiate forwarding of connections to local port "port" through the secure
1474 * channel to host:port from remote side.
1477 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
1478 u_short port_to_connect, int gateway_ports)
1480 channel_request_forwarding(
1482 host_to_connect, port_to_connect,
1483 gateway_ports, /*remote_fwd*/ 0);
1487 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
1488 * (SSH_CHANNEL_RPORT_LISTENER).
1491 channel_request_forwarding(
1492 const char *listen_address, u_short listen_port,
1493 const char *host_to_connect, u_short port_to_connect,
1494 int gateway_ports, int remote_fwd)
1496 int success, ch, sock, on = 1, ctype;
1497 struct addrinfo hints, *ai, *aitop;
1498 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1500 struct linger linger;
1503 host = listen_address;
1504 ctype = SSH_CHANNEL_RPORT_LISTENER;
1506 host = host_to_connect;
1507 ctype =SSH_CHANNEL_PORT_LISTENER;
1510 if (strlen(host) > sizeof(channels[0].path) - 1)
1511 packet_disconnect("Forward host name too long.");
1513 /* XXX listen_address is currently ignored */
1515 * getaddrinfo returns a loopback address if the hostname is
1516 * set to NULL and hints.ai_flags is not AI_PASSIVE
1518 memset(&hints, 0, sizeof(hints));
1519 hints.ai_family = IPv4or6;
1520 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
1521 hints.ai_socktype = SOCK_STREAM;
1522 snprintf(strport, sizeof strport, "%d", listen_port);
1523 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
1524 packet_disconnect("getaddrinfo: fatal error");
1527 for (ai = aitop; ai; ai = ai->ai_next) {
1528 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1530 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1531 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1532 error("channel_request_forwarding: getnameinfo failed");
1535 /* Create a port to listen for the host. */
1536 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1538 /* this is no error since kernel may not support ipv6 */
1539 verbose("socket: %.100s", strerror(errno));
1543 * Set socket options. We would like the socket to disappear
1544 * as soon as it has been closed for whatever reason.
1546 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
1548 linger.l_linger = 5;
1549 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
1550 debug("Local forwarding listening on %s port %s.", ntop, strport);
1552 /* Bind the socket to the address. */
1553 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1554 /* address can be in use ipv6 address is already bound */
1556 error("bind: %.100s", strerror(errno));
1558 verbose("bind: %.100s", strerror(errno));
1563 /* Start listening for connections on the socket. */
1564 if (listen(sock, 5) < 0) {
1565 error("listen: %.100s", strerror(errno));
1569 /* Allocate a channel number for the socket. */
1570 ch = channel_new("port listener", ctype, sock, sock, -1,
1571 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1572 0, xstrdup("port listener"), 1);
1573 strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
1574 channels[ch].host_port = port_to_connect;
1575 channels[ch].listening_port = listen_port;
1579 packet_disconnect("cannot listen port: %d", listen_port); /*XXX ?disconnect? */
1580 freeaddrinfo(aitop);
1584 * Initiate forwarding of connections to port "port" on remote host through
1585 * the secure channel to host:port from local side.
1589 channel_request_remote_forwarding(u_short listen_port,
1590 const char *host_to_connect, u_short port_to_connect)
1592 int payload_len, type, success = 0;
1594 /* Record locally that connection to this host/port is permitted. */
1595 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
1596 fatal("channel_request_remote_forwarding: too many forwards");
1598 /* Send the forward request to the remote side. */
1600 const char *address_to_bind = "0.0.0.0";
1601 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1602 packet_put_cstring("tcpip-forward");
1603 packet_put_char(0); /* boolean: want reply */
1604 packet_put_cstring(address_to_bind);
1605 packet_put_int(listen_port);
1607 packet_write_wait();
1608 /* Assume that server accepts the request */
1611 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
1612 packet_put_int(listen_port);
1613 packet_put_cstring(host_to_connect);
1614 packet_put_int(port_to_connect);
1616 packet_write_wait();
1618 /* Wait for response from the remote side. */
1619 type = packet_read(&payload_len);
1621 case SSH_SMSG_SUCCESS:
1624 case SSH_SMSG_FAILURE:
1625 log("Warning: Server denied remote port forwarding.");
1628 /* Unknown packet */
1629 packet_disconnect("Protocol error for port forward request:"
1630 "received packet type %d.", type);
1634 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
1635 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
1636 permitted_opens[num_permitted_opens].listen_port = listen_port;
1637 num_permitted_opens++;
1642 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
1643 * listening for the port, and sends back a success reply (or disconnect
1644 * message if there was an error). This never returns if there was an error.
1648 channel_input_port_forward_request(int is_root, int gateway_ports)
1650 u_short port, host_port;
1653 /* Get arguments from the packet. */
1654 port = packet_get_int();
1655 hostname = packet_get_string(NULL);
1656 host_port = packet_get_int();
1660 * Check that an unprivileged user is not trying to forward a
1663 if (port < IPPORT_RESERVED && !is_root)
1664 packet_disconnect("Requested forwarding of port %d but user is not root.",
1667 /* Initiate forwarding */
1668 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
1670 /* Free the argument string. */
1674 /* XXX move to aux.c */
1676 channel_connect_to(const char *host, u_short host_port)
1678 struct addrinfo hints, *ai, *aitop;
1679 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1683 memset(&hints, 0, sizeof(hints));
1684 hints.ai_family = IPv4or6;
1685 hints.ai_socktype = SOCK_STREAM;
1686 snprintf(strport, sizeof strport, "%d", host_port);
1687 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
1688 error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
1691 for (ai = aitop; ai; ai = ai->ai_next) {
1692 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1694 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1695 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1696 error("channel_connect_to: getnameinfo failed");
1699 /* Create the socket. */
1700 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1702 error("socket: %.100s", strerror(errno));
1705 /* Connect to the host/port. */
1706 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1707 error("connect %.100s port %s: %.100s", ntop, strport,
1710 continue; /* fail -- try next */
1712 break; /* success */
1715 freeaddrinfo(aitop);
1717 error("connect %.100s port %d: failed.", host, host_port);
1724 channel_connect_by_listen_adress(u_short listen_port)
1727 for (i = 0; i < num_permitted_opens; i++)
1728 if (permitted_opens[i].listen_port == listen_port)
1729 return channel_connect_to(
1730 permitted_opens[i].host_to_connect,
1731 permitted_opens[i].port_to_connect);
1732 debug("channel_connect_by_listen_adress: unknown listen_port %d", listen_port);
1737 * This is called after receiving PORT_OPEN message. This attempts to
1738 * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
1739 * or CHANNEL_OPEN_FAILURE.
1743 channel_input_port_open(int type, int plen, void *ctxt)
1746 char *host, *originator_string;
1747 int remote_channel, sock = -1, newch, i, denied;
1748 unsigned int host_len, originator_len;
1750 /* Get remote channel number. */
1751 remote_channel = packet_get_int();
1753 /* Get host name to connect to. */
1754 host = packet_get_string(&host_len);
1756 /* Get port to connect to. */
1757 host_port = packet_get_int();
1759 /* Get remote originator name. */
1760 if (have_hostname_in_open) {
1761 originator_string = packet_get_string(&originator_len);
1762 originator_len += 4; /* size of packet_int */
1764 originator_string = xstrdup("unknown (remote did not supply name)");
1765 originator_len = 0; /* no originator supplied */
1768 packet_integrity_check(plen,
1769 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN);
1771 /* Check if opening that port is permitted. */
1773 if (!all_opens_permitted) {
1774 /* Go trough all permitted ports. */
1775 for (i = 0; i < num_permitted_opens; i++)
1776 if (permitted_opens[i].port_to_connect == host_port &&
1777 strcmp(permitted_opens[i].host_to_connect, host) == 0)
1780 /* Check if we found the requested port among those permitted. */
1781 if (i >= num_permitted_opens) {
1782 /* The port is not permitted. */
1783 log("Received request to connect to %.100s:%d, but the request was denied.",
1788 sock = denied ? -1 : channel_connect_to(host, host_port);
1790 /* Allocate a channel for this connection. */
1791 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
1792 channels[newch].remote_id = remote_channel;
1794 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1795 packet_put_int(remote_channel);
1796 packet_put_int(newch);
1799 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1800 packet_put_int(remote_channel);
1807 * Creates an internet domain socket for listening for X11 connections.
1808 * Returns a suitable value for the DISPLAY variable, or NULL if an error
1812 #define NUM_SOCKS 10
1815 x11_create_display_inet(int screen_number, int x11_display_offset)
1817 int display_number, sock;
1819 struct addrinfo hints, *ai, *aitop;
1820 char strport[NI_MAXSERV];
1821 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
1823 char hostname[MAXHOSTNAMELEN];
1825 for (display_number = x11_display_offset;
1826 display_number < MAX_DISPLAYS;
1828 port = 6000 + display_number;
1829 memset(&hints, 0, sizeof(hints));
1830 hints.ai_family = IPv4or6;
1831 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
1832 hints.ai_socktype = SOCK_STREAM;
1833 snprintf(strport, sizeof strport, "%d", port);
1834 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
1835 error("getaddrinfo: %.100s", gai_strerror(gaierr));
1838 for (ai = aitop; ai; ai = ai->ai_next) {
1839 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1841 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1843 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
1844 error("socket: %.100s", strerror(errno));
1847 debug("x11_create_display_inet: Socket family %d not supported",
1852 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1853 debug("bind port %d: %.100s", port, strerror(errno));
1854 shutdown(sock, SHUT_RDWR);
1860 for (n = 0; n < num_socks; n++) {
1861 shutdown(socks[n], SHUT_RDWR);
1867 socks[num_socks++] = sock;
1868 #ifndef DONT_TRY_OTHER_AF
1869 if (num_socks == NUM_SOCKS)
1878 if (display_number >= MAX_DISPLAYS) {
1879 error("Failed to allocate internet-domain X11 display socket.");
1882 /* Start listening for connections on the socket. */
1883 for (n = 0; n < num_socks; n++) {
1885 if (listen(sock, 5) < 0) {
1886 error("listen: %.100s", strerror(errno));
1887 shutdown(sock, SHUT_RDWR);
1893 /* Set up a suitable value for the DISPLAY variable. */
1895 if (gethostname(hostname, sizeof(hostname)) < 0)
1896 fatal("gethostname: %.100s", strerror(errno));
1898 #ifdef IPADDR_IN_DISPLAY
1900 * HPUX detects the local hostname in the DISPLAY variable and tries
1901 * to set up a shared memory connection to the server, which it
1902 * incorrectly supposes to be local.
1904 * The workaround - as used in later $$H and other programs - is
1905 * is to set display to the host's IP address.
1909 struct in_addr my_addr;
1911 he = gethostbyname(hostname);
1913 error("[X11-broken-fwd-hostname-workaround] Could not get "
1914 "IP address for hostname %s.", hostname);
1916 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
1917 "Could not get IP address for hostname %s.", hostname);
1919 shutdown(sock, SHUT_RDWR);
1925 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
1927 /* Set DISPLAY to <ip address>:screen.display */
1928 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
1929 display_number, screen_number);
1931 #else /* IPADDR_IN_DISPLAY */
1932 /* Just set DISPLAY to hostname:screen.display */
1933 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1934 display_number, screen_number);
1935 #endif /* IPADDR_IN_DISPLAY */
1937 /* Allocate a channel for each socket. */
1938 for (n = 0; n < num_socks; n++) {
1940 (void) channel_new("x11 listener",
1941 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
1942 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
1943 0, xstrdup("X11 inet listener"), 1);
1946 /* Return a suitable value for the DISPLAY environment variable. */
1947 return xstrdup(display);
1951 #define X_UNIX_PATH "/tmp/.X11-unix/X"
1956 connect_local_xsocket(unsigned int dnr)
1958 static const char *const x_sockets[] = {
1960 "/var/X/.X11-unix/X" "%u",
1961 "/usr/spool/sockets/X11/" "%u",
1965 struct sockaddr_un addr;
1966 const char *const * path;
1968 for (path = x_sockets; *path; ++path) {
1969 sock = socket(AF_UNIX, SOCK_STREAM, 0);
1971 error("socket: %.100s", strerror(errno));
1972 memset(&addr, 0, sizeof(addr));
1973 addr.sun_family = AF_UNIX;
1974 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
1975 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
1979 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
1984 x11_connect_display(void)
1986 int display_number, sock = 0;
1987 const char *display;
1988 char buf[1024], *cp;
1989 struct addrinfo hints, *ai, *aitop;
1990 char strport[NI_MAXSERV];
1993 /* Try to open a socket for the local X server. */
1994 display = getenv("DISPLAY");
1996 error("DISPLAY not set.");
2000 * Now we decode the value of the DISPLAY variable and make a
2001 * connection to the real X server.
2005 * Check if it is a unix domain socket. Unix domain displays are in
2006 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2008 if (strncmp(display, "unix:", 5) == 0 ||
2009 display[0] == ':') {
2010 /* Connect to the unix domain socket. */
2011 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2012 error("Could not parse display number from DISPLAY: %.100s",
2016 /* Create a socket. */
2017 sock = connect_local_xsocket(display_number);
2021 /* OK, we now have a connection to the display. */
2025 * Connect to an inet socket. The DISPLAY value is supposedly
2026 * hostname:d[.s], where hostname may also be numeric IP address.
2028 strncpy(buf, display, sizeof(buf));
2029 buf[sizeof(buf) - 1] = 0;
2030 cp = strchr(buf, ':');
2032 error("Could not find ':' in DISPLAY: %.100s", display);
2036 /* buf now contains the host name. But first we parse the display number. */
2037 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2038 error("Could not parse display number from DISPLAY: %.100s",
2043 /* Look up the host address */
2044 memset(&hints, 0, sizeof(hints));
2045 hints.ai_family = IPv4or6;
2046 hints.ai_socktype = SOCK_STREAM;
2047 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2048 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2049 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2052 for (ai = aitop; ai; ai = ai->ai_next) {
2053 /* Create a socket. */
2054 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2056 debug("socket: %.100s", strerror(errno));
2059 /* Connect it to the display. */
2060 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2061 debug("connect %.100s port %d: %.100s", buf,
2062 6000 + display_number, strerror(errno));
2069 freeaddrinfo(aitop);
2071 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2079 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2080 * the remote channel number. We should do whatever we want, and respond
2081 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2085 x11_input_open(int type, int plen, void *ctxt)
2087 int remote_channel, sock = 0, newch;
2089 unsigned int remote_len;
2091 /* Get remote channel number. */
2092 remote_channel = packet_get_int();
2094 /* Get remote originator name. */
2095 if (have_hostname_in_open) {
2096 remote_host = packet_get_string(&remote_len);
2099 remote_host = xstrdup("unknown (remote did not supply name)");
2103 debug("Received X11 open request.");
2104 packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
2106 /* Obtain a connection to the real X display. */
2107 sock = x11_connect_display();
2109 /* Send refusal to the remote host. */
2110 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2111 packet_put_int(remote_channel);
2114 /* Allocate a channel for this connection. */
2115 newch = channel_allocate(
2116 (x11_saved_proto == NULL) ?
2117 SSH_CHANNEL_OPEN : SSH_CHANNEL_X11_OPEN,
2119 channels[newch].remote_id = remote_channel;
2121 /* Send a confirmation to the remote host. */
2122 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2123 packet_put_int(remote_channel);
2124 packet_put_int(newch);
2129 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2131 deny_input_open(int type, int plen, void *ctxt)
2133 int rchan = packet_get_int();
2135 case SSH_SMSG_AGENT_OPEN:
2136 error("Warning: ssh server tried agent forwarding.");
2138 case SSH_SMSG_X11_OPEN:
2139 error("Warning: ssh server tried X11 forwarding.");
2142 error("deny_input_open: type %d plen %d", type, plen);
2145 error("Warning: this is probably a break in attempt by a malicious server.");
2146 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2147 packet_put_int(rchan);
2152 * Requests forwarding of X11 connections, generates fake authentication
2153 * data, and enables authentication spoofing.
2157 x11_request_forwarding_with_spoofing(int client_session_id,
2158 const char *proto, const char *data)
2160 unsigned int data_len = (unsigned int) strlen(data) / 2;
2161 unsigned int i, value;
2167 cp = getenv("DISPLAY");
2169 cp = strchr(cp, ':');
2171 cp = strchr(cp, '.');
2173 screen_number = atoi(cp + 1);
2177 /* Save protocol name. */
2178 x11_saved_proto = xstrdup(proto);
2181 * Extract real authentication data and generate fake data of the
2184 x11_saved_data = xmalloc(data_len);
2185 x11_fake_data = xmalloc(data_len);
2186 for (i = 0; i < data_len; i++) {
2187 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2188 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2190 rand = arc4random();
2191 x11_saved_data[i] = value;
2192 x11_fake_data[i] = rand & 0xff;
2195 x11_saved_data_len = data_len;
2196 x11_fake_data_len = data_len;
2198 /* Convert the fake data into hex. */
2199 new_data = xmalloc(2 * data_len + 1);
2200 for (i = 0; i < data_len; i++)
2201 sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]);
2203 /* Send the request packet. */
2205 channel_request_start(client_session_id, "x11-req", 0);
2206 packet_put_char(0); /* XXX bool single connection */
2208 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2210 packet_put_cstring(proto);
2211 packet_put_cstring(new_data);
2212 packet_put_int(screen_number);
2214 packet_write_wait();
2218 /* Sends a message to the server to request authentication fd forwarding. */
2221 auth_request_forwarding()
2223 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2225 packet_write_wait();
2229 * Returns the name of the forwarded authentication socket. Returns NULL if
2230 * there is no forwarded authentication socket. The returned value points to
2235 auth_get_socket_name()
2237 return channel_forwarded_auth_socket_name;
2240 /* removes the agent forwarding socket */
2243 cleanup_socket(void)
2245 unlink(channel_forwarded_auth_socket_name);
2246 rmdir(channel_forwarded_auth_socket_dir);
2250 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2251 * This starts forwarding authentication requests.
2255 auth_input_request_forwarding(struct passwd * pw)
2258 struct sockaddr_un sunaddr;
2260 if (auth_get_socket_name() != NULL)
2261 fatal("Protocol error: authentication forwarding requested twice.");
2263 /* Temporarily drop privileged uid for mkdir/bind. */
2264 temporarily_use_uid(pw->pw_uid);
2266 /* Allocate a buffer for the socket name, and format the name. */
2267 channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
2268 channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
2269 strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
2271 /* Create private directory for socket */
2272 if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL) {
2273 packet_send_debug("Agent forwarding disabled: mkdtemp() failed: %.100s",
2276 xfree(channel_forwarded_auth_socket_name);
2277 xfree(channel_forwarded_auth_socket_dir);
2278 channel_forwarded_auth_socket_name = NULL;
2279 channel_forwarded_auth_socket_dir = NULL;
2282 snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
2283 channel_forwarded_auth_socket_dir, (int) getpid());
2285 if (atexit(cleanup_socket) < 0) {
2288 packet_disconnect("socket: %.100s", strerror(saved));
2290 /* Create the socket. */
2291 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2293 packet_disconnect("socket: %.100s", strerror(errno));
2295 /* Bind it to the name. */
2296 memset(&sunaddr, 0, sizeof(sunaddr));
2297 sunaddr.sun_family = AF_UNIX;
2298 strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
2299 sizeof(sunaddr.sun_path));
2301 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2302 packet_disconnect("bind: %.100s", strerror(errno));
2304 /* Restore the privileged uid. */
2307 /* Start listening on the socket. */
2308 if (listen(sock, 5) < 0)
2309 packet_disconnect("listen: %.100s", strerror(errno));
2311 /* Allocate a channel for the authentication agent socket. */
2312 newch = channel_new("auth socket",
2313 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2314 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2315 0, xstrdup("auth socket"), 1);
2317 strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
2318 sizeof(channels[newch].path));
2322 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2325 auth_input_open_request(int type, int plen, void *ctxt)
2327 int remch, sock, newch;
2330 packet_integrity_check(plen, 4, type);
2332 /* Read the remote channel number from the message. */
2333 remch = packet_get_int();
2336 * Get a connection to the local authentication agent (this may again
2339 sock = ssh_get_authentication_socket();
2342 * If we could not connect the agent, send an error message back to
2343 * the server. This should never happen unless the agent dies,
2344 * because authentication forwarding is only enabled if we have an
2348 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2349 packet_put_int(remch);
2353 debug("Forwarding authentication connection.");
2356 * Dummy host name. This will be freed when the channel is freed; it
2357 * will still be valid in the packet_put_string below since the
2358 * channel cannot yet be freed at that point.
2360 dummyname = xstrdup("authentication agent connection");
2362 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
2363 channels[newch].remote_id = remch;
2365 /* Send a confirmation to the remote host. */
2366 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2367 packet_put_int(remch);
2368 packet_put_int(newch);
2373 channel_start_open(int id)
2375 Channel *c = channel_lookup(id);
2377 log("channel_open: %d: bad id", id);
2380 debug("send channel open %d", id);
2381 packet_start(SSH2_MSG_CHANNEL_OPEN);
2382 packet_put_cstring(c->ctype);
2383 packet_put_int(c->self);
2384 packet_put_int(c->local_window);
2385 packet_put_int(c->local_maxpacket);
2388 channel_open(int id)
2391 channel_start_open(id);
2395 channel_request(int id, char *service, int wantconfirm)
2397 channel_request_start(id, service, wantconfirm);
2399 debug("channel request %d: %s", id, service) ;
2402 channel_request_start(int id, char *service, int wantconfirm)
2404 Channel *c = channel_lookup(id);
2406 log("channel_request: %d: bad id", id);
2409 packet_start(SSH2_MSG_CHANNEL_REQUEST);
2410 packet_put_int(c->remote_id);
2411 packet_put_cstring(service);
2412 packet_put_char(wantconfirm);
2415 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
2417 Channel *c = channel_lookup(id);
2419 log("channel_register_callback: %d: bad id", id);
2422 c->cb_event = mtype;
2427 channel_register_cleanup(int id, channel_callback_fn *fn)
2429 Channel *c = channel_lookup(id);
2431 log("channel_register_cleanup: %d: bad id", id);
2434 c->dettach_user = fn;
2437 channel_cancel_cleanup(int id)
2439 Channel *c = channel_lookup(id);
2441 log("channel_cancel_cleanup: %d: bad id", id);
2444 c->dettach_user = NULL;
2447 channel_register_filter(int id, channel_filter_fn *fn)
2449 Channel *c = channel_lookup(id);
2451 log("channel_register_filter: %d: bad id", id);
2454 c->input_filter = fn;
2458 channel_set_fds(int id, int rfd, int wfd, int efd,
2459 int extusage, int nonblock)
2461 Channel *c = channel_lookup(id);
2462 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
2463 fatal("channel_activate for non-larval channel %d.", id);
2464 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
2465 c->type = SSH_CHANNEL_OPEN;
2466 /* XXX window size? */
2467 c->local_window = c->local_window_max = c->local_maxpacket * 2;
2468 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2469 packet_put_int(c->remote_id);
2470 packet_put_int(c->local_window);