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".
15 * SSH2 support added by Markus Friedl.
16 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 RCSID("$OpenBSD: channels.c,v 1.230 2005/12/28 22:46:06 stevesk Exp $");
56 #include "pathnames.h"
61 #define CHAN_RBUF 16*1024
64 * Pointer to an array containing all allocated channels. The array is
65 * dynamically extended as needed.
67 static Channel **channels = NULL;
70 * Size of the channel array. All slots of the array must always be
71 * initialized (at least the type field); unused slots set to NULL
73 static u_int channels_alloc = 0;
76 * Maximum file descriptor value used in any of the channels. This is
77 * updated in channel_new.
79 static int channel_max_fd = 0;
82 /* -- tcp forwarding */
85 * Data structure for storing which hosts are permitted for forward requests.
86 * The local sides of any remote forwards are stored in this array to prevent
87 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
88 * network (which might be behind a firewall).
91 char *host_to_connect; /* Connect to 'host'. */
92 u_short port_to_connect; /* Connect to 'port'. */
93 u_short listen_port; /* Remote side should listen port number. */
96 /* List of all permitted host/port pairs to connect. */
97 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
99 /* Number of permitted host/port pairs in the array. */
100 static int num_permitted_opens = 0;
102 * If this is true, all opens are permitted. This is the case on the server
103 * on which we have to trust the client anyway, and the user could do
104 * anything after logging in anyway.
106 static int all_opens_permitted = 0;
109 /* -- X11 forwarding */
111 /* Maximum number of fake X11 displays to try. */
112 #define MAX_DISPLAYS 1000
114 /* Saved X11 local (client) display. */
115 static char *x11_saved_display = NULL;
117 /* Saved X11 authentication protocol name. */
118 static char *x11_saved_proto = NULL;
120 /* Saved X11 authentication data. This is the real data. */
121 static char *x11_saved_data = NULL;
122 static u_int x11_saved_data_len = 0;
125 * Fake X11 authentication data. This is what the server will be sending us;
126 * we should replace any occurrences of this by the real data.
128 static char *x11_fake_data = NULL;
129 static u_int x11_fake_data_len;
132 /* -- agent forwarding */
136 /* AF_UNSPEC or AF_INET or AF_INET6 */
137 static int IPv4or6 = AF_UNSPEC;
140 static void port_open_helper(Channel *c, char *rtype);
142 /* -- channel core */
145 channel_by_id(int id)
149 if (id < 0 || (u_int)id >= channels_alloc) {
150 logit("channel_by_id: %d: bad id", id);
155 logit("channel_by_id: %d: bad id: channel free", id);
162 * Returns the channel if it is allowed to receive protocol messages.
163 * Private channels, like listening sockets, may not receive messages.
166 channel_lookup(int id)
170 if ((c = channel_by_id(id)) == NULL)
174 case SSH_CHANNEL_X11_OPEN:
175 case SSH_CHANNEL_LARVAL:
176 case SSH_CHANNEL_CONNECTING:
177 case SSH_CHANNEL_DYNAMIC:
178 case SSH_CHANNEL_OPENING:
179 case SSH_CHANNEL_OPEN:
180 case SSH_CHANNEL_INPUT_DRAINING:
181 case SSH_CHANNEL_OUTPUT_DRAINING:
185 logit("Non-public channel %d, type %d.", id, c->type);
190 * Register filedescriptors for a channel, used when allocating a channel or
191 * when the channel consumer/producer is ready, e.g. shell exec'd
195 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
196 int extusage, int nonblock)
198 /* Update the maximum file descriptor value. */
199 channel_max_fd = MAX(channel_max_fd, rfd);
200 channel_max_fd = MAX(channel_max_fd, wfd);
201 channel_max_fd = MAX(channel_max_fd, efd);
203 /* XXX set close-on-exec -markus */
207 c->sock = (rfd == wfd) ? rfd : -1;
208 c->ctl_fd = -1; /* XXX: set elsewhere */
210 c->extended_usage = extusage;
212 /* XXX ugly hack: nonblock is only set by the server */
213 if (nonblock && isatty(c->rfd)) {
214 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
216 if (!isatty(c->wfd)) {
217 error("channel %d: wfd %d is not a tty?",
223 c->wfd_isatty = isatty(c->wfd);
225 /* enable nonblocking mode */
237 * Allocate a new channel object and set its type and socket. This will cause
238 * remote_name to be freed.
242 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
243 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
249 /* Do initial allocation if this is the first call. */
250 if (channels_alloc == 0) {
252 channels = xmalloc(channels_alloc * sizeof(Channel *));
253 for (i = 0; i < channels_alloc; i++)
256 /* Try to find a free slot where to put the new channel. */
257 for (found = -1, i = 0; i < channels_alloc; i++)
258 if (channels[i] == NULL) {
259 /* Found a free slot. */
264 /* There are no free slots. Take last+1 slot and expand the array. */
265 found = channels_alloc;
266 if (channels_alloc > 10000)
267 fatal("channel_new: internal error: channels_alloc %d "
268 "too big.", channels_alloc);
269 channels = xrealloc(channels,
270 (channels_alloc + 10) * sizeof(Channel *));
271 channels_alloc += 10;
272 debug2("channel: expanding %d", channels_alloc);
273 for (i = found; i < channels_alloc; i++)
276 /* Initialize and return new channel. */
277 c = channels[found] = xmalloc(sizeof(Channel));
278 memset(c, 0, sizeof(Channel));
279 buffer_init(&c->input);
280 buffer_init(&c->output);
281 buffer_init(&c->extended);
282 c->ostate = CHAN_OUTPUT_OPEN;
283 c->istate = CHAN_INPUT_OPEN;
285 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
289 c->local_window = window;
290 c->local_window_max = window;
291 c->local_consumed = 0;
292 c->local_maxpacket = maxpack;
294 c->remote_name = xstrdup(remote_name);
295 c->remote_window = 0;
296 c->remote_maxpacket = 0;
298 c->single_connection = 0;
299 c->detach_user = NULL;
302 c->confirm_ctx = NULL;
303 c->input_filter = NULL;
304 debug("channel %d: new [%s]", found, remote_name);
309 channel_find_maxfd(void)
315 for (i = 0; i < channels_alloc; i++) {
318 max = MAX(max, c->rfd);
319 max = MAX(max, c->wfd);
320 max = MAX(max, c->efd);
327 channel_close_fd(int *fdp)
329 int ret = 0, fd = *fdp;
334 if (fd == channel_max_fd)
335 channel_max_fd = channel_find_maxfd();
340 /* Close all channel fd/socket. */
343 channel_close_fds(Channel *c)
345 debug3("channel %d: close_fds r %d w %d e %d c %d",
346 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
348 channel_close_fd(&c->sock);
349 channel_close_fd(&c->ctl_fd);
350 channel_close_fd(&c->rfd);
351 channel_close_fd(&c->wfd);
352 channel_close_fd(&c->efd);
355 /* Free the channel and close its fd/socket. */
358 channel_free(Channel *c)
363 for (n = 0, i = 0; i < channels_alloc; i++)
366 debug("channel %d: free: %s, nchannels %u", c->self,
367 c->remote_name ? c->remote_name : "???", n);
369 s = channel_open_message();
370 debug3("channel %d: status: %s", c->self, s);
374 shutdown(c->sock, SHUT_RDWR);
376 shutdown(c->ctl_fd, SHUT_RDWR);
377 channel_close_fds(c);
378 buffer_free(&c->input);
379 buffer_free(&c->output);
380 buffer_free(&c->extended);
381 if (c->remote_name) {
382 xfree(c->remote_name);
383 c->remote_name = NULL;
385 channels[c->self] = NULL;
390 channel_free_all(void)
394 for (i = 0; i < channels_alloc; i++)
395 if (channels[i] != NULL)
396 channel_free(channels[i]);
400 * Closes the sockets/fds of all channels. This is used to close extra file
401 * descriptors after a fork.
405 channel_close_all(void)
409 for (i = 0; i < channels_alloc; i++)
410 if (channels[i] != NULL)
411 channel_close_fds(channels[i]);
415 * Stop listening to channels.
419 channel_stop_listening(void)
424 for (i = 0; i < channels_alloc; i++) {
428 case SSH_CHANNEL_AUTH_SOCKET:
429 case SSH_CHANNEL_PORT_LISTENER:
430 case SSH_CHANNEL_RPORT_LISTENER:
431 case SSH_CHANNEL_X11_LISTENER:
432 channel_close_fd(&c->sock);
441 * Returns true if no channel has too much buffered data, and false if one or
442 * more channel is overfull.
446 channel_not_very_much_buffered_data(void)
451 for (i = 0; i < channels_alloc; i++) {
453 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
456 buffer_len(&c->input) > packet_get_maxsize()) {
457 debug2("channel %d: big input buffer %d",
458 c->self, buffer_len(&c->input));
462 if (buffer_len(&c->output) > packet_get_maxsize()) {
463 debug2("channel %d: big output buffer %u > %u",
464 c->self, buffer_len(&c->output),
465 packet_get_maxsize());
473 /* Returns true if any channel is still open. */
476 channel_still_open(void)
481 for (i = 0; i < channels_alloc; i++) {
486 case SSH_CHANNEL_X11_LISTENER:
487 case SSH_CHANNEL_PORT_LISTENER:
488 case SSH_CHANNEL_RPORT_LISTENER:
489 case SSH_CHANNEL_CLOSED:
490 case SSH_CHANNEL_AUTH_SOCKET:
491 case SSH_CHANNEL_DYNAMIC:
492 case SSH_CHANNEL_CONNECTING:
493 case SSH_CHANNEL_ZOMBIE:
495 case SSH_CHANNEL_LARVAL:
497 fatal("cannot happen: SSH_CHANNEL_LARVAL");
499 case SSH_CHANNEL_OPENING:
500 case SSH_CHANNEL_OPEN:
501 case SSH_CHANNEL_X11_OPEN:
503 case SSH_CHANNEL_INPUT_DRAINING:
504 case SSH_CHANNEL_OUTPUT_DRAINING:
506 fatal("cannot happen: OUT_DRAIN");
509 fatal("channel_still_open: bad channel type %d", c->type);
516 /* Returns the id of an open channel suitable for keepaliving */
519 channel_find_open(void)
524 for (i = 0; i < channels_alloc; i++) {
526 if (c == NULL || c->remote_id < 0)
529 case SSH_CHANNEL_CLOSED:
530 case SSH_CHANNEL_DYNAMIC:
531 case SSH_CHANNEL_X11_LISTENER:
532 case SSH_CHANNEL_PORT_LISTENER:
533 case SSH_CHANNEL_RPORT_LISTENER:
534 case SSH_CHANNEL_OPENING:
535 case SSH_CHANNEL_CONNECTING:
536 case SSH_CHANNEL_ZOMBIE:
538 case SSH_CHANNEL_LARVAL:
539 case SSH_CHANNEL_AUTH_SOCKET:
540 case SSH_CHANNEL_OPEN:
541 case SSH_CHANNEL_X11_OPEN:
543 case SSH_CHANNEL_INPUT_DRAINING:
544 case SSH_CHANNEL_OUTPUT_DRAINING:
546 fatal("cannot happen: OUT_DRAIN");
549 fatal("channel_find_open: bad channel type %d", c->type);
558 * Returns a message describing the currently open forwarded connections,
559 * suitable for sending to the client. The message contains crlf pairs for
564 channel_open_message(void)
571 buffer_init(&buffer);
572 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
573 buffer_append(&buffer, buf, strlen(buf));
574 for (i = 0; i < channels_alloc; i++) {
579 case SSH_CHANNEL_X11_LISTENER:
580 case SSH_CHANNEL_PORT_LISTENER:
581 case SSH_CHANNEL_RPORT_LISTENER:
582 case SSH_CHANNEL_CLOSED:
583 case SSH_CHANNEL_AUTH_SOCKET:
584 case SSH_CHANNEL_ZOMBIE:
586 case SSH_CHANNEL_LARVAL:
587 case SSH_CHANNEL_OPENING:
588 case SSH_CHANNEL_CONNECTING:
589 case SSH_CHANNEL_DYNAMIC:
590 case SSH_CHANNEL_OPEN:
591 case SSH_CHANNEL_X11_OPEN:
592 case SSH_CHANNEL_INPUT_DRAINING:
593 case SSH_CHANNEL_OUTPUT_DRAINING:
594 snprintf(buf, sizeof buf,
595 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
596 c->self, c->remote_name,
597 c->type, c->remote_id,
598 c->istate, buffer_len(&c->input),
599 c->ostate, buffer_len(&c->output),
600 c->rfd, c->wfd, c->ctl_fd);
601 buffer_append(&buffer, buf, strlen(buf));
604 fatal("channel_open_message: bad channel type %d", c->type);
608 buffer_append(&buffer, "\0", 1);
609 cp = xstrdup(buffer_ptr(&buffer));
610 buffer_free(&buffer);
615 channel_send_open(int id)
617 Channel *c = channel_lookup(id);
620 logit("channel_send_open: %d: bad id", id);
623 debug2("channel %d: send open", id);
624 packet_start(SSH2_MSG_CHANNEL_OPEN);
625 packet_put_cstring(c->ctype);
626 packet_put_int(c->self);
627 packet_put_int(c->local_window);
628 packet_put_int(c->local_maxpacket);
633 channel_request_start(int id, char *service, int wantconfirm)
635 Channel *c = channel_lookup(id);
638 logit("channel_request_start: %d: unknown channel id", id);
641 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
642 packet_start(SSH2_MSG_CHANNEL_REQUEST);
643 packet_put_int(c->remote_id);
644 packet_put_cstring(service);
645 packet_put_char(wantconfirm);
648 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
650 Channel *c = channel_lookup(id);
653 logit("channel_register_comfirm: %d: bad id", id);
657 c->confirm_ctx = ctx;
660 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
662 Channel *c = channel_by_id(id);
665 logit("channel_register_cleanup: %d: bad id", id);
669 c->detach_close = do_close;
672 channel_cancel_cleanup(int id)
674 Channel *c = channel_by_id(id);
677 logit("channel_cancel_cleanup: %d: bad id", id);
680 c->detach_user = NULL;
684 channel_register_filter(int id, channel_filter_fn *fn)
686 Channel *c = channel_lookup(id);
689 logit("channel_register_filter: %d: bad id", id);
692 c->input_filter = fn;
696 channel_set_fds(int id, int rfd, int wfd, int efd,
697 int extusage, int nonblock, u_int window_max)
699 Channel *c = channel_lookup(id);
701 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
702 fatal("channel_activate for non-larval channel %d.", id);
703 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
704 c->type = SSH_CHANNEL_OPEN;
705 c->local_window = c->local_window_max = window_max;
706 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
707 packet_put_int(c->remote_id);
708 packet_put_int(c->local_window);
713 * 'channel_pre*' are called just before select() to add any bits relevant to
714 * channels in the select bitmasks.
717 * 'channel_post*': perform any appropriate operations for channels which
718 * have events pending.
720 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
721 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
722 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
725 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
727 FD_SET(c->sock, readset);
731 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
733 debug3("channel %d: waiting for connection", c->self);
734 FD_SET(c->sock, writeset);
738 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
740 if (buffer_len(&c->input) < packet_get_maxsize())
741 FD_SET(c->sock, readset);
742 if (buffer_len(&c->output) > 0)
743 FD_SET(c->sock, writeset);
747 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
749 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
751 /* check buffer limits */
752 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
754 if (c->istate == CHAN_INPUT_OPEN &&
756 buffer_len(&c->input) < limit)
757 FD_SET(c->rfd, readset);
758 if (c->ostate == CHAN_OUTPUT_OPEN ||
759 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
760 if (buffer_len(&c->output) > 0) {
761 FD_SET(c->wfd, writeset);
762 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
763 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
764 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
765 c->self, c->efd, buffer_len(&c->extended));
770 /** XXX check close conditions, too */
771 if (compat20 && c->efd != -1) {
772 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
773 buffer_len(&c->extended) > 0)
774 FD_SET(c->efd, writeset);
775 else if (!(c->flags & CHAN_EOF_SENT) &&
776 c->extended_usage == CHAN_EXTENDED_READ &&
777 buffer_len(&c->extended) < c->remote_window)
778 FD_SET(c->efd, readset);
780 /* XXX: What about efd? races? */
781 if (compat20 && c->ctl_fd != -1 &&
782 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
783 FD_SET(c->ctl_fd, readset);
787 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
789 if (buffer_len(&c->input) == 0) {
790 packet_start(SSH_MSG_CHANNEL_CLOSE);
791 packet_put_int(c->remote_id);
793 c->type = SSH_CHANNEL_CLOSED;
794 debug2("channel %d: closing after input drain.", c->self);
799 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
801 if (buffer_len(&c->output) == 0)
804 FD_SET(c->sock, writeset);
808 * This is a special state for X11 authentication spoofing. An opened X11
809 * connection (when authentication spoofing is being done) remains in this
810 * state until the first packet has been completely read. The authentication
811 * data in that packet is then substituted by the real data if it matches the
812 * fake data, and the channel is put into normal mode.
813 * XXX All this happens at the client side.
814 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
817 x11_open_helper(Buffer *b)
820 u_int proto_len, data_len;
822 /* Check if the fixed size part of the packet is in buffer. */
823 if (buffer_len(b) < 12)
826 /* Parse the lengths of variable-length fields. */
828 if (ucp[0] == 0x42) { /* Byte order MSB first. */
829 proto_len = 256 * ucp[6] + ucp[7];
830 data_len = 256 * ucp[8] + ucp[9];
831 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
832 proto_len = ucp[6] + 256 * ucp[7];
833 data_len = ucp[8] + 256 * ucp[9];
835 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
840 /* Check if the whole packet is in buffer. */
842 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
845 /* Check if authentication protocol matches. */
846 if (proto_len != strlen(x11_saved_proto) ||
847 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
848 debug2("X11 connection uses different authentication protocol.");
851 /* Check if authentication data matches our fake data. */
852 if (data_len != x11_fake_data_len ||
853 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
854 x11_fake_data, x11_fake_data_len) != 0) {
855 debug2("X11 auth data does not match fake data.");
858 /* Check fake data length */
859 if (x11_fake_data_len != x11_saved_data_len) {
860 error("X11 fake_data_len %d != saved_data_len %d",
861 x11_fake_data_len, x11_saved_data_len);
865 * Received authentication protocol and data match
866 * our fake data. Substitute the fake data with real
869 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
870 x11_saved_data, x11_saved_data_len);
875 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
877 int ret = x11_open_helper(&c->output);
880 /* Start normal processing for the channel. */
881 c->type = SSH_CHANNEL_OPEN;
882 channel_pre_open_13(c, readset, writeset);
883 } else if (ret == -1) {
885 * We have received an X11 connection that has bad
886 * authentication information.
888 logit("X11 connection rejected because of wrong authentication.");
889 buffer_clear(&c->input);
890 buffer_clear(&c->output);
891 channel_close_fd(&c->sock);
893 c->type = SSH_CHANNEL_CLOSED;
894 packet_start(SSH_MSG_CHANNEL_CLOSE);
895 packet_put_int(c->remote_id);
901 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
903 int ret = x11_open_helper(&c->output);
905 /* c->force_drain = 1; */
908 c->type = SSH_CHANNEL_OPEN;
909 channel_pre_open(c, readset, writeset);
910 } else if (ret == -1) {
911 logit("X11 connection rejected because of wrong authentication.");
912 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
914 buffer_clear(&c->input);
916 buffer_clear(&c->output);
917 /* for proto v1, the peer will send an IEOF */
919 chan_write_failed(c);
921 c->type = SSH_CHANNEL_OPEN;
922 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
926 /* try to decode a socks4 header */
928 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
931 u_int len, have, i, found;
937 struct in_addr dest_addr;
940 debug2("channel %d: decode socks4", c->self);
942 have = buffer_len(&c->input);
943 len = sizeof(s4_req);
946 p = buffer_ptr(&c->input);
947 for (found = 0, i = len; i < have; i++) {
953 /* the peer is probably sending garbage */
954 debug("channel %d: decode socks4: too long",
961 buffer_get(&c->input, (char *)&s4_req.version, 1);
962 buffer_get(&c->input, (char *)&s4_req.command, 1);
963 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
964 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
965 have = buffer_len(&c->input);
966 p = buffer_ptr(&c->input);
968 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
970 fatal("channel %d: decode socks4: len %d > have %d",
972 strlcpy(username, p, sizeof(username));
973 buffer_consume(&c->input, len);
974 buffer_consume(&c->input, 1); /* trailing '\0' */
976 host = inet_ntoa(s4_req.dest_addr);
977 strlcpy(c->path, host, sizeof(c->path));
978 c->host_port = ntohs(s4_req.dest_port);
980 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
981 c->self, host, c->host_port, s4_req.command);
983 if (s4_req.command != 1) {
984 debug("channel %d: cannot handle: socks4 cn %d",
985 c->self, s4_req.command);
988 s4_rsp.version = 0; /* vn: 0 for reply */
989 s4_rsp.command = 90; /* cd: req granted */
990 s4_rsp.dest_port = 0; /* ignored */
991 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
992 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
996 /* try to decode a socks5 header */
997 #define SSH_SOCKS5_AUTHDONE 0x1000
998 #define SSH_SOCKS5_NOAUTH 0x00
999 #define SSH_SOCKS5_IPV4 0x01
1000 #define SSH_SOCKS5_DOMAIN 0x03
1001 #define SSH_SOCKS5_IPV6 0x04
1002 #define SSH_SOCKS5_CONNECT 0x01
1003 #define SSH_SOCKS5_SUCCESS 0x00
1006 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
1014 u_int16_t dest_port;
1015 u_char *p, dest_addr[255+1];
1016 u_int have, i, found, nmethods, addrlen, af;
1018 debug2("channel %d: decode socks5", c->self);
1019 p = buffer_ptr(&c->input);
1022 have = buffer_len(&c->input);
1023 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1024 /* format: ver | nmethods | methods */
1028 if (have < nmethods + 2)
1030 /* look for method: "NO AUTHENTICATION REQUIRED" */
1031 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1032 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1038 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1042 buffer_consume(&c->input, nmethods + 2);
1043 buffer_put_char(&c->output, 0x05); /* version */
1044 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1045 FD_SET(c->sock, writeset);
1046 c->flags |= SSH_SOCKS5_AUTHDONE;
1047 debug2("channel %d: socks5 auth done", c->self);
1048 return 0; /* need more */
1050 debug2("channel %d: socks5 post auth", c->self);
1051 if (have < sizeof(s5_req)+1)
1052 return 0; /* need more */
1053 memcpy((char *)&s5_req, p, sizeof(s5_req));
1054 if (s5_req.version != 0x05 ||
1055 s5_req.command != SSH_SOCKS5_CONNECT ||
1056 s5_req.reserved != 0x00) {
1057 debug2("channel %d: only socks5 connect supported", c->self);
1060 switch (s5_req.atyp){
1061 case SSH_SOCKS5_IPV4:
1065 case SSH_SOCKS5_DOMAIN:
1066 addrlen = p[sizeof(s5_req)];
1069 case SSH_SOCKS5_IPV6:
1074 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1077 if (have < 4 + addrlen + 2)
1079 buffer_consume(&c->input, sizeof(s5_req));
1080 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1081 buffer_consume(&c->input, 1); /* host string length */
1082 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1083 buffer_get(&c->input, (char *)&dest_port, 2);
1084 dest_addr[addrlen] = '\0';
1085 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1086 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1087 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1089 c->host_port = ntohs(dest_port);
1091 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1092 c->self, c->path, c->host_port, s5_req.command);
1094 s5_rsp.version = 0x05;
1095 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1096 s5_rsp.reserved = 0; /* ignored */
1097 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1098 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1099 dest_port = 0; /* ignored */
1101 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1102 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1103 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1107 /* dynamic port forwarding */
1109 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1115 have = buffer_len(&c->input);
1117 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1118 /* buffer_dump(&c->input); */
1119 /* check if the fixed size part of the packet is in buffer. */
1122 FD_SET(c->sock, readset);
1125 /* try to guess the protocol */
1126 p = buffer_ptr(&c->input);
1129 ret = channel_decode_socks4(c, readset, writeset);
1132 ret = channel_decode_socks5(c, readset, writeset);
1140 } else if (ret == 0) {
1141 debug2("channel %d: pre_dynamic: need more", c->self);
1143 FD_SET(c->sock, readset);
1145 /* switch to the next state */
1146 c->type = SSH_CHANNEL_OPENING;
1147 port_open_helper(c, "direct-tcpip");
1151 /* This is our fake X11 server socket. */
1153 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1156 struct sockaddr addr;
1159 char buf[16384], *remote_ipaddr;
1162 if (FD_ISSET(c->sock, readset)) {
1163 debug("X11 connection requested.");
1164 addrlen = sizeof(addr);
1165 newsock = accept(c->sock, &addr, &addrlen);
1166 if (c->single_connection) {
1167 debug2("single_connection: closing X11 listener.");
1168 channel_close_fd(&c->sock);
1172 error("accept: %.100s", strerror(errno));
1175 set_nodelay(newsock);
1176 remote_ipaddr = get_peer_ipaddr(newsock);
1177 remote_port = get_peer_port(newsock);
1178 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1179 remote_ipaddr, remote_port);
1181 nc = channel_new("accepted x11 socket",
1182 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1183 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1185 packet_start(SSH2_MSG_CHANNEL_OPEN);
1186 packet_put_cstring("x11");
1187 packet_put_int(nc->self);
1188 packet_put_int(nc->local_window_max);
1189 packet_put_int(nc->local_maxpacket);
1190 /* originator ipaddr and port */
1191 packet_put_cstring(remote_ipaddr);
1192 if (datafellows & SSH_BUG_X11FWD) {
1193 debug2("ssh2 x11 bug compat mode");
1195 packet_put_int(remote_port);
1199 packet_start(SSH_SMSG_X11_OPEN);
1200 packet_put_int(nc->self);
1201 if (packet_get_protocol_flags() &
1202 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1203 packet_put_cstring(buf);
1206 xfree(remote_ipaddr);
1211 port_open_helper(Channel *c, char *rtype)
1215 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1216 int remote_port = get_peer_port(c->sock);
1218 direct = (strcmp(rtype, "direct-tcpip") == 0);
1220 snprintf(buf, sizeof buf,
1221 "%s: listening port %d for %.100s port %d, "
1222 "connect from %.200s port %d",
1223 rtype, c->listening_port, c->path, c->host_port,
1224 remote_ipaddr, remote_port);
1226 xfree(c->remote_name);
1227 c->remote_name = xstrdup(buf);
1230 packet_start(SSH2_MSG_CHANNEL_OPEN);
1231 packet_put_cstring(rtype);
1232 packet_put_int(c->self);
1233 packet_put_int(c->local_window_max);
1234 packet_put_int(c->local_maxpacket);
1236 /* target host, port */
1237 packet_put_cstring(c->path);
1238 packet_put_int(c->host_port);
1240 /* listen address, port */
1241 packet_put_cstring(c->path);
1242 packet_put_int(c->listening_port);
1244 /* originator host and port */
1245 packet_put_cstring(remote_ipaddr);
1246 packet_put_int((u_int)remote_port);
1249 packet_start(SSH_MSG_PORT_OPEN);
1250 packet_put_int(c->self);
1251 packet_put_cstring(c->path);
1252 packet_put_int(c->host_port);
1253 if (packet_get_protocol_flags() &
1254 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1255 packet_put_cstring(c->remote_name);
1258 xfree(remote_ipaddr);
1262 channel_set_reuseaddr(int fd)
1267 * Set socket options.
1268 * Allow local port reuse in TIME_WAIT.
1270 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1271 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1275 * This socket is listening for connections to a forwarded TCP/IP port.
1278 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1281 struct sockaddr addr;
1282 int newsock, nextstate;
1286 if (FD_ISSET(c->sock, readset)) {
1287 debug("Connection to port %d forwarding "
1288 "to %.100s port %d requested.",
1289 c->listening_port, c->path, c->host_port);
1291 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1292 nextstate = SSH_CHANNEL_OPENING;
1293 rtype = "forwarded-tcpip";
1295 if (c->host_port == 0) {
1296 nextstate = SSH_CHANNEL_DYNAMIC;
1297 rtype = "dynamic-tcpip";
1299 nextstate = SSH_CHANNEL_OPENING;
1300 rtype = "direct-tcpip";
1304 addrlen = sizeof(addr);
1305 newsock = accept(c->sock, &addr, &addrlen);
1307 error("accept: %.100s", strerror(errno));
1310 set_nodelay(newsock);
1311 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1312 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1313 nc->listening_port = c->listening_port;
1314 nc->host_port = c->host_port;
1315 strlcpy(nc->path, c->path, sizeof(nc->path));
1317 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1319 * do not call the channel_post handler until
1320 * this flag has been reset by a pre-handler.
1321 * otherwise the FD_ISSET calls might overflow
1325 port_open_helper(nc, rtype);
1331 * This is the authentication agent socket listening for connections from
1335 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1339 struct sockaddr addr;
1342 if (FD_ISSET(c->sock, readset)) {
1343 addrlen = sizeof(addr);
1344 newsock = accept(c->sock, &addr, &addrlen);
1346 error("accept from auth socket: %.100s", strerror(errno));
1349 nc = channel_new("accepted auth socket",
1350 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1351 c->local_window_max, c->local_maxpacket,
1352 0, "accepted auth socket", 1);
1354 packet_start(SSH2_MSG_CHANNEL_OPEN);
1355 packet_put_cstring("auth-agent@openssh.com");
1356 packet_put_int(nc->self);
1357 packet_put_int(c->local_window_max);
1358 packet_put_int(c->local_maxpacket);
1360 packet_start(SSH_SMSG_AGENT_OPEN);
1361 packet_put_int(nc->self);
1368 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1371 socklen_t sz = sizeof(err);
1373 if (FD_ISSET(c->sock, writeset)) {
1374 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1376 error("getsockopt SO_ERROR failed");
1379 debug("channel %d: connected", c->self);
1380 c->type = SSH_CHANNEL_OPEN;
1382 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1383 packet_put_int(c->remote_id);
1384 packet_put_int(c->self);
1385 packet_put_int(c->local_window);
1386 packet_put_int(c->local_maxpacket);
1388 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1389 packet_put_int(c->remote_id);
1390 packet_put_int(c->self);
1393 debug("channel %d: not connected: %s",
1394 c->self, strerror(err));
1396 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1397 packet_put_int(c->remote_id);
1398 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1399 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1400 packet_put_cstring(strerror(err));
1401 packet_put_cstring("");
1404 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1405 packet_put_int(c->remote_id);
1414 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1416 char buf[CHAN_RBUF];
1420 FD_ISSET(c->rfd, readset)) {
1421 len = read(c->rfd, buf, sizeof(buf));
1422 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1425 debug2("channel %d: read<=0 rfd %d len %d",
1426 c->self, c->rfd, len);
1427 if (c->type != SSH_CHANNEL_OPEN) {
1428 debug2("channel %d: not open", c->self);
1431 } else if (compat13) {
1432 buffer_clear(&c->output);
1433 c->type = SSH_CHANNEL_INPUT_DRAINING;
1434 debug2("channel %d: input draining.", c->self);
1436 chan_read_failed(c);
1440 if (c->input_filter != NULL) {
1441 if (c->input_filter(c, buf, len) == -1) {
1442 debug2("channel %d: filter stops", c->self);
1443 chan_read_failed(c);
1445 } else if (c->datagram) {
1446 buffer_put_string(&c->input, buf, len);
1448 buffer_append(&c->input, buf, len);
1454 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1461 /* Send buffered output data to the socket. */
1463 FD_ISSET(c->wfd, writeset) &&
1464 buffer_len(&c->output) > 0) {
1466 data = buffer_get_string(&c->output, &dlen);
1467 /* ignore truncated writes, datagrams might get lost */
1468 c->local_consumed += dlen + 4;
1469 len = write(c->wfd, data, dlen);
1471 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1474 if (c->type != SSH_CHANNEL_OPEN)
1477 chan_write_failed(c);
1482 data = buffer_ptr(&c->output);
1483 dlen = buffer_len(&c->output);
1485 /* XXX: Later AIX versions can't push as much data to tty */
1486 if (compat20 && c->wfd_isatty)
1487 dlen = MIN(dlen, 8*1024);
1489 len = write(c->wfd, data, dlen);
1490 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1493 if (c->type != SSH_CHANNEL_OPEN) {
1494 debug2("channel %d: not open", c->self);
1497 } else if (compat13) {
1498 buffer_clear(&c->output);
1499 debug2("channel %d: input draining.", c->self);
1500 c->type = SSH_CHANNEL_INPUT_DRAINING;
1502 chan_write_failed(c);
1506 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1507 if (tcgetattr(c->wfd, &tio) == 0 &&
1508 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1510 * Simulate echo to reduce the impact of
1511 * traffic analysis. We need to match the
1512 * size of a SSH2_MSG_CHANNEL_DATA message
1513 * (4 byte channel id + data)
1515 packet_send_ignore(4 + len);
1519 buffer_consume(&c->output, len);
1520 if (compat20 && len > 0) {
1521 c->local_consumed += len;
1527 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1529 char buf[CHAN_RBUF];
1532 /** XXX handle drain efd, too */
1534 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1535 FD_ISSET(c->efd, writeset) &&
1536 buffer_len(&c->extended) > 0) {
1537 len = write(c->efd, buffer_ptr(&c->extended),
1538 buffer_len(&c->extended));
1539 debug2("channel %d: written %d to efd %d",
1540 c->self, len, c->efd);
1541 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1544 debug2("channel %d: closing write-efd %d",
1546 channel_close_fd(&c->efd);
1548 buffer_consume(&c->extended, len);
1549 c->local_consumed += len;
1551 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1552 FD_ISSET(c->efd, readset)) {
1553 len = read(c->efd, buf, sizeof(buf));
1554 debug2("channel %d: read %d from efd %d",
1555 c->self, len, c->efd);
1556 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1559 debug2("channel %d: closing read-efd %d",
1561 channel_close_fd(&c->efd);
1563 buffer_append(&c->extended, buf, len);
1570 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1575 /* Monitor control fd to detect if the slave client exits */
1576 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1577 len = read(c->ctl_fd, buf, sizeof(buf));
1578 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1581 debug2("channel %d: ctl read<=0", c->self);
1582 if (c->type != SSH_CHANNEL_OPEN) {
1583 debug2("channel %d: not open", c->self);
1587 chan_read_failed(c);
1588 chan_write_failed(c);
1592 fatal("%s: unexpected data on ctl fd", __func__);
1597 channel_check_window(Channel *c)
1599 if (c->type == SSH_CHANNEL_OPEN &&
1600 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1601 c->local_window < c->local_window_max/2 &&
1602 c->local_consumed > 0) {
1603 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1604 packet_put_int(c->remote_id);
1605 packet_put_int(c->local_consumed);
1607 debug2("channel %d: window %d sent adjust %d",
1608 c->self, c->local_window,
1610 c->local_window += c->local_consumed;
1611 c->local_consumed = 0;
1617 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1621 channel_handle_rfd(c, readset, writeset);
1622 channel_handle_wfd(c, readset, writeset);
1625 channel_handle_efd(c, readset, writeset);
1626 channel_handle_ctl(c, readset, writeset);
1627 channel_check_window(c);
1631 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1635 /* Send buffered output data to the socket. */
1636 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1637 len = write(c->sock, buffer_ptr(&c->output),
1638 buffer_len(&c->output));
1640 buffer_clear(&c->output);
1642 buffer_consume(&c->output, len);
1647 channel_handler_init_20(void)
1649 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1650 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1651 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1652 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1653 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1654 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1655 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1656 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1658 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1659 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1660 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1661 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1662 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1663 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1664 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1668 channel_handler_init_13(void)
1670 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1671 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1672 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1673 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1674 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1675 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1676 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1677 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1678 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1680 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1681 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1682 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1683 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1684 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1685 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1686 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1690 channel_handler_init_15(void)
1692 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1693 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1694 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1695 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1696 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1697 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1698 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1700 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1701 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1702 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1703 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1704 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1705 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1709 channel_handler_init(void)
1713 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1714 channel_pre[i] = NULL;
1715 channel_post[i] = NULL;
1718 channel_handler_init_20();
1720 channel_handler_init_13();
1722 channel_handler_init_15();
1725 /* gc dead channels */
1727 channel_garbage_collect(Channel *c)
1731 if (c->detach_user != NULL) {
1732 if (!chan_is_dead(c, c->detach_close))
1734 debug2("channel %d: gc: notify user", c->self);
1735 c->detach_user(c->self, NULL);
1736 /* if we still have a callback */
1737 if (c->detach_user != NULL)
1739 debug2("channel %d: gc: user detached", c->self);
1741 if (!chan_is_dead(c, 1))
1743 debug2("channel %d: garbage collecting", c->self);
1748 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1750 static int did_init = 0;
1755 channel_handler_init();
1758 for (i = 0; i < channels_alloc; i++) {
1762 if (ftab[c->type] != NULL)
1763 (*ftab[c->type])(c, readset, writeset);
1764 channel_garbage_collect(c);
1769 * Allocate/update select bitmasks and add any bits relevant to channels in
1773 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1774 u_int *nallocp, int rekeying)
1778 n = MAX(*maxfdp, channel_max_fd);
1780 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1781 /* perhaps check sz < nalloc/2 and shrink? */
1782 if (*readsetp == NULL || sz > *nallocp) {
1783 *readsetp = xrealloc(*readsetp, sz);
1784 *writesetp = xrealloc(*writesetp, sz);
1788 memset(*readsetp, 0, sz);
1789 memset(*writesetp, 0, sz);
1792 channel_handler(channel_pre, *readsetp, *writesetp);
1796 * After select, perform any appropriate operations for channels which have
1800 channel_after_select(fd_set * readset, fd_set * writeset)
1802 channel_handler(channel_post, readset, writeset);
1806 /* If there is data to send to the connection, enqueue some of it now. */
1809 channel_output_poll(void)
1814 for (i = 0; i < channels_alloc; i++) {
1820 * We are only interested in channels that can have buffered
1824 if (c->type != SSH_CHANNEL_OPEN &&
1825 c->type != SSH_CHANNEL_INPUT_DRAINING)
1828 if (c->type != SSH_CHANNEL_OPEN)
1832 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1833 /* XXX is this true? */
1834 debug3("channel %d: will not send data after close", c->self);
1838 /* Get the amount of buffered data for this channel. */
1839 if ((c->istate == CHAN_INPUT_OPEN ||
1840 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1841 (len = buffer_len(&c->input)) > 0) {
1847 data = buffer_get_string(&c->input,
1849 packet_start(SSH2_MSG_CHANNEL_DATA);
1850 packet_put_int(c->remote_id);
1851 packet_put_string(data, dlen);
1853 c->remote_window -= dlen + 4;
1859 * Send some data for the other side over the secure
1863 if (len > c->remote_window)
1864 len = c->remote_window;
1865 if (len > c->remote_maxpacket)
1866 len = c->remote_maxpacket;
1868 if (packet_is_interactive()) {
1872 /* Keep the packets at reasonable size. */
1873 if (len > packet_get_maxsize()/2)
1874 len = packet_get_maxsize()/2;
1878 packet_start(compat20 ?
1879 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1880 packet_put_int(c->remote_id);
1881 packet_put_string(buffer_ptr(&c->input), len);
1883 buffer_consume(&c->input, len);
1884 c->remote_window -= len;
1886 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1888 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1890 * input-buffer is empty and read-socket shutdown:
1891 * tell peer, that we will not send more data: send IEOF.
1892 * hack for extended data: delay EOF if EFD still in use.
1894 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1895 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1896 c->self, c->efd, buffer_len(&c->extended));
1900 /* Send extended data, i.e. stderr */
1902 !(c->flags & CHAN_EOF_SENT) &&
1903 c->remote_window > 0 &&
1904 (len = buffer_len(&c->extended)) > 0 &&
1905 c->extended_usage == CHAN_EXTENDED_READ) {
1906 debug2("channel %d: rwin %u elen %u euse %d",
1907 c->self, c->remote_window, buffer_len(&c->extended),
1909 if (len > c->remote_window)
1910 len = c->remote_window;
1911 if (len > c->remote_maxpacket)
1912 len = c->remote_maxpacket;
1913 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1914 packet_put_int(c->remote_id);
1915 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1916 packet_put_string(buffer_ptr(&c->extended), len);
1918 buffer_consume(&c->extended, len);
1919 c->remote_window -= len;
1920 debug2("channel %d: sent ext data %d", c->self, len);
1926 /* -- protocol input */
1929 channel_input_data(int type, u_int32_t seq, void *ctxt)
1936 /* Get the channel number and verify it. */
1937 id = packet_get_int();
1938 c = channel_lookup(id);
1940 packet_disconnect("Received data for nonexistent channel %d.", id);
1942 /* Ignore any data for non-open channels (might happen on close) */
1943 if (c->type != SSH_CHANNEL_OPEN &&
1944 c->type != SSH_CHANNEL_X11_OPEN)
1948 data = packet_get_string(&data_len);
1951 * Ignore data for protocol > 1.3 if output end is no longer open.
1952 * For protocol 2 the sending side is reducing its window as it sends
1953 * data, so we must 'fake' consumption of the data in order to ensure
1954 * that window updates are sent back. Otherwise the connection might
1957 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1959 c->local_window -= data_len;
1960 c->local_consumed += data_len;
1967 if (data_len > c->local_maxpacket) {
1968 logit("channel %d: rcvd big packet %d, maxpack %d",
1969 c->self, data_len, c->local_maxpacket);
1971 if (data_len > c->local_window) {
1972 logit("channel %d: rcvd too much data %d, win %d",
1973 c->self, data_len, c->local_window);
1977 c->local_window -= data_len;
1981 buffer_put_string(&c->output, data, data_len);
1983 buffer_append(&c->output, data, data_len);
1988 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1992 u_int data_len, tcode;
1995 /* Get the channel number and verify it. */
1996 id = packet_get_int();
1997 c = channel_lookup(id);
2000 packet_disconnect("Received extended_data for bad channel %d.", id);
2001 if (c->type != SSH_CHANNEL_OPEN) {
2002 logit("channel %d: ext data for non open", id);
2005 if (c->flags & CHAN_EOF_RCVD) {
2006 if (datafellows & SSH_BUG_EXTEOF)
2007 debug("channel %d: accepting ext data after eof", id);
2009 packet_disconnect("Received extended_data after EOF "
2010 "on channel %d.", id);
2012 tcode = packet_get_int();
2014 c->extended_usage != CHAN_EXTENDED_WRITE ||
2015 tcode != SSH2_EXTENDED_DATA_STDERR) {
2016 logit("channel %d: bad ext data", c->self);
2019 data = packet_get_string(&data_len);
2021 if (data_len > c->local_window) {
2022 logit("channel %d: rcvd too much extended_data %d, win %d",
2023 c->self, data_len, c->local_window);
2027 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2028 c->local_window -= data_len;
2029 buffer_append(&c->extended, data, data_len);
2034 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2039 id = packet_get_int();
2041 c = channel_lookup(id);
2043 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2046 /* XXX force input close */
2047 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2048 debug("channel %d: FORCE input drain", c->self);
2049 c->istate = CHAN_INPUT_WAIT_DRAIN;
2050 if (buffer_len(&c->input) == 0)
2057 channel_input_close(int type, u_int32_t seq, void *ctxt)
2062 id = packet_get_int();
2064 c = channel_lookup(id);
2066 packet_disconnect("Received close for nonexistent channel %d.", id);
2069 * Send a confirmation that we have closed the channel and no more
2070 * data is coming for it.
2072 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2073 packet_put_int(c->remote_id);
2077 * If the channel is in closed state, we have sent a close request,
2078 * and the other side will eventually respond with a confirmation.
2079 * Thus, we cannot free the channel here, because then there would be
2080 * no-one to receive the confirmation. The channel gets freed when
2081 * the confirmation arrives.
2083 if (c->type != SSH_CHANNEL_CLOSED) {
2085 * Not a closed channel - mark it as draining, which will
2086 * cause it to be freed later.
2088 buffer_clear(&c->input);
2089 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2093 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2095 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2097 int id = packet_get_int();
2098 Channel *c = channel_lookup(id);
2102 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2103 chan_rcvd_oclose(c);
2107 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2109 int id = packet_get_int();
2110 Channel *c = channel_lookup(id);
2114 packet_disconnect("Received close confirmation for "
2115 "out-of-range channel %d.", id);
2116 if (c->type != SSH_CHANNEL_CLOSED)
2117 packet_disconnect("Received close confirmation for "
2118 "non-closed channel %d (type %d).", id, c->type);
2123 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2128 id = packet_get_int();
2129 c = channel_lookup(id);
2131 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2132 packet_disconnect("Received open confirmation for "
2133 "non-opening channel %d.", id);
2134 remote_id = packet_get_int();
2135 /* Record the remote channel number and mark that the channel is now open. */
2136 c->remote_id = remote_id;
2137 c->type = SSH_CHANNEL_OPEN;
2140 c->remote_window = packet_get_int();
2141 c->remote_maxpacket = packet_get_int();
2143 debug2("callback start");
2144 c->confirm(c->self, c->confirm_ctx);
2145 debug2("callback done");
2147 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2148 c->remote_window, c->remote_maxpacket);
2154 reason2txt(int reason)
2157 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2158 return "administratively prohibited";
2159 case SSH2_OPEN_CONNECT_FAILED:
2160 return "connect failed";
2161 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2162 return "unknown channel type";
2163 case SSH2_OPEN_RESOURCE_SHORTAGE:
2164 return "resource shortage";
2166 return "unknown reason";
2170 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2173 char *msg = NULL, *lang = NULL;
2176 id = packet_get_int();
2177 c = channel_lookup(id);
2179 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2180 packet_disconnect("Received open failure for "
2181 "non-opening channel %d.", id);
2183 reason = packet_get_int();
2184 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2185 msg = packet_get_string(NULL);
2186 lang = packet_get_string(NULL);
2188 logit("channel %d: open failed: %s%s%s", id,
2189 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2196 /* Free the channel. This will also close the socket. */
2201 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2210 /* Get the channel number and verify it. */
2211 id = packet_get_int();
2212 c = channel_lookup(id);
2215 logit("Received window adjust for non-open channel %d.", id);
2218 adjust = packet_get_int();
2220 debug2("channel %d: rcvd adjust %u", id, adjust);
2221 c->remote_window += adjust;
2225 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2229 char *host, *originator_string;
2230 int remote_id, sock = -1;
2232 remote_id = packet_get_int();
2233 host = packet_get_string(NULL);
2234 host_port = packet_get_int();
2236 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2237 originator_string = packet_get_string(NULL);
2239 originator_string = xstrdup("unknown (remote did not supply name)");
2242 sock = channel_connect_to(host, host_port);
2244 c = channel_new("connected socket",
2245 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2246 originator_string, 1);
2247 c->remote_id = remote_id;
2249 xfree(originator_string);
2251 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2252 packet_put_int(remote_id);
2259 /* -- tcp forwarding */
2262 channel_set_af(int af)
2268 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2269 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2272 int sock, r, success = 0, wildcard = 0, is_client;
2273 struct addrinfo hints, *ai, *aitop;
2274 const char *host, *addr;
2275 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2277 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2278 listen_addr : host_to_connect;
2279 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2282 error("No forward host name.");
2285 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2286 error("Forward host name too long.");
2291 * Determine whether or not a port forward listens to loopback,
2292 * specified address or wildcard. On the client, a specified bind
2293 * address will always override gateway_ports. On the server, a
2294 * gateway_ports of 1 (``yes'') will override the client's
2295 * specification and force a wildcard bind, whereas a value of 2
2296 * (``clientspecified'') will bind to whatever address the client
2299 * Special-case listen_addrs are:
2301 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2302 * "" (empty string), "*" -> wildcard v4/v6
2303 * "localhost" -> loopback v4/v6
2306 if (listen_addr == NULL) {
2307 /* No address specified: default to gateway_ports setting */
2310 } else if (gateway_ports || is_client) {
2311 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2312 strcmp(listen_addr, "0.0.0.0") == 0) ||
2313 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2314 (!is_client && gateway_ports == 1))
2316 else if (strcmp(listen_addr, "localhost") != 0)
2320 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2321 type, wildcard, (addr == NULL) ? "NULL" : addr);
2324 * getaddrinfo returns a loopback address if the hostname is
2325 * set to NULL and hints.ai_flags is not AI_PASSIVE
2327 memset(&hints, 0, sizeof(hints));
2328 hints.ai_family = IPv4or6;
2329 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2330 hints.ai_socktype = SOCK_STREAM;
2331 snprintf(strport, sizeof strport, "%d", listen_port);
2332 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2334 /* This really shouldn't happen */
2335 packet_disconnect("getaddrinfo: fatal error: %s",
2338 error("channel_setup_fwd_listener: "
2339 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2344 for (ai = aitop; ai; ai = ai->ai_next) {
2345 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2347 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2348 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2349 error("channel_setup_fwd_listener: getnameinfo failed");
2352 /* Create a port to listen for the host. */
2353 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2355 /* this is no error since kernel may not support ipv6 */
2356 verbose("socket: %.100s", strerror(errno));
2360 channel_set_reuseaddr(sock);
2362 debug("Local forwarding listening on %s port %s.", ntop, strport);
2364 /* Bind the socket to the address. */
2365 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2366 /* address can be in use ipv6 address is already bound */
2368 error("bind: %.100s", strerror(errno));
2370 verbose("bind: %.100s", strerror(errno));
2375 /* Start listening for connections on the socket. */
2376 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2377 error("listen: %.100s", strerror(errno));
2381 /* Allocate a channel number for the socket. */
2382 c = channel_new("port listener", type, sock, sock, -1,
2383 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2384 0, "port listener", 1);
2385 strlcpy(c->path, host, sizeof(c->path));
2386 c->host_port = port_to_connect;
2387 c->listening_port = listen_port;
2391 error("channel_setup_fwd_listener: cannot listen to port: %d",
2393 freeaddrinfo(aitop);
2398 channel_cancel_rport_listener(const char *host, u_short port)
2403 for (i = 0; i < channels_alloc; i++) {
2404 Channel *c = channels[i];
2406 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2407 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2408 c->listening_port == port) {
2409 debug2("%s: close channel %d", __func__, i);
2418 /* protocol local port fwd, used by ssh (and sshd in v1) */
2420 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2421 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2423 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2424 listen_host, listen_port, host_to_connect, port_to_connect,
2428 /* protocol v2 remote port fwd, used by sshd */
2430 channel_setup_remote_fwd_listener(const char *listen_address,
2431 u_short listen_port, int gateway_ports)
2433 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2434 listen_address, listen_port, NULL, 0, gateway_ports);
2438 * Initiate forwarding of connections to port "port" on remote host through
2439 * the secure channel to host:port from local side.
2443 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2444 const char *host_to_connect, u_short port_to_connect)
2446 int type, success = 0;
2448 /* Record locally that connection to this host/port is permitted. */
2449 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2450 fatal("channel_request_remote_forwarding: too many forwards");
2452 /* Send the forward request to the remote side. */
2454 const char *address_to_bind;
2455 if (listen_host == NULL)
2456 address_to_bind = "localhost";
2457 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2458 address_to_bind = "";
2460 address_to_bind = listen_host;
2462 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2463 packet_put_cstring("tcpip-forward");
2464 packet_put_char(1); /* boolean: want reply */
2465 packet_put_cstring(address_to_bind);
2466 packet_put_int(listen_port);
2468 packet_write_wait();
2469 /* Assume that server accepts the request */
2472 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2473 packet_put_int(listen_port);
2474 packet_put_cstring(host_to_connect);
2475 packet_put_int(port_to_connect);
2477 packet_write_wait();
2479 /* Wait for response from the remote side. */
2480 type = packet_read();
2482 case SSH_SMSG_SUCCESS:
2485 case SSH_SMSG_FAILURE:
2486 logit("Warning: Server denied remote port forwarding.");
2489 /* Unknown packet */
2490 packet_disconnect("Protocol error for port forward request:"
2491 "received packet type %d.", type);
2495 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2496 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2497 permitted_opens[num_permitted_opens].listen_port = listen_port;
2498 num_permitted_opens++;
2503 * Request cancellation of remote forwarding of connection host:port from
2507 channel_request_rforward_cancel(const char *host, u_short port)
2514 for (i = 0; i < num_permitted_opens; i++) {
2515 if (permitted_opens[i].host_to_connect != NULL &&
2516 permitted_opens[i].listen_port == port)
2519 if (i >= num_permitted_opens) {
2520 debug("%s: requested forward not found", __func__);
2523 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2524 packet_put_cstring("cancel-tcpip-forward");
2526 packet_put_cstring(host == NULL ? "" : host);
2527 packet_put_int(port);
2530 permitted_opens[i].listen_port = 0;
2531 permitted_opens[i].port_to_connect = 0;
2532 xfree(permitted_opens[i].host_to_connect);
2533 permitted_opens[i].host_to_connect = NULL;
2537 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2538 * listening for the port, and sends back a success reply (or disconnect
2539 * message if there was an error). This never returns if there was an error.
2543 channel_input_port_forward_request(int is_root, int gateway_ports)
2545 u_short port, host_port;
2548 /* Get arguments from the packet. */
2549 port = packet_get_int();
2550 hostname = packet_get_string(NULL);
2551 host_port = packet_get_int();
2555 * Check that an unprivileged user is not trying to forward a
2558 if (port < IPPORT_RESERVED && !is_root)
2560 "Requested forwarding of port %d but user is not root.",
2563 packet_disconnect("Dynamic forwarding denied.");
2566 /* Initiate forwarding */
2567 channel_setup_local_fwd_listener(NULL, port, hostname,
2568 host_port, gateway_ports);
2570 /* Free the argument string. */
2575 * Permits opening to any host/port if permitted_opens[] is empty. This is
2576 * usually called by the server, because the user could connect to any port
2577 * anyway, and the server has no way to know but to trust the client anyway.
2580 channel_permit_all_opens(void)
2582 if (num_permitted_opens == 0)
2583 all_opens_permitted = 1;
2587 channel_add_permitted_opens(char *host, int port)
2589 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2590 fatal("channel_request_remote_forwarding: too many forwards");
2591 debug("allow port forwarding to host %s port %d", host, port);
2593 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2594 permitted_opens[num_permitted_opens].port_to_connect = port;
2595 num_permitted_opens++;
2597 all_opens_permitted = 0;
2601 channel_clear_permitted_opens(void)
2605 for (i = 0; i < num_permitted_opens; i++)
2606 if (permitted_opens[i].host_to_connect != NULL)
2607 xfree(permitted_opens[i].host_to_connect);
2608 num_permitted_opens = 0;
2613 /* return socket to remote host, port */
2615 connect_to(const char *host, u_short port)
2617 struct addrinfo hints, *ai, *aitop;
2618 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2622 memset(&hints, 0, sizeof(hints));
2623 hints.ai_family = IPv4or6;
2624 hints.ai_socktype = SOCK_STREAM;
2625 snprintf(strport, sizeof strport, "%d", port);
2626 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2627 error("connect_to %.100s: unknown host (%s)", host,
2628 gai_strerror(gaierr));
2631 for (ai = aitop; ai; ai = ai->ai_next) {
2632 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2634 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2635 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2636 error("connect_to: getnameinfo failed");
2639 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2641 if (ai->ai_next == NULL)
2642 error("socket: %.100s", strerror(errno));
2644 verbose("socket: %.100s", strerror(errno));
2647 if (set_nonblock(sock) == -1)
2648 fatal("%s: set_nonblock(%d)", __func__, sock);
2649 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2650 errno != EINPROGRESS) {
2651 error("connect_to %.100s port %s: %.100s", ntop, strport,
2654 continue; /* fail -- try next */
2656 break; /* success */
2659 freeaddrinfo(aitop);
2661 error("connect_to %.100s port %d: failed.", host, port);
2670 channel_connect_by_listen_address(u_short listen_port)
2674 for (i = 0; i < num_permitted_opens; i++)
2675 if (permitted_opens[i].host_to_connect != NULL &&
2676 permitted_opens[i].listen_port == listen_port)
2678 permitted_opens[i].host_to_connect,
2679 permitted_opens[i].port_to_connect);
2680 error("WARNING: Server requests forwarding for unknown listen_port %d",
2685 /* Check if connecting to that port is permitted and connect. */
2687 channel_connect_to(const char *host, u_short port)
2691 permit = all_opens_permitted;
2693 for (i = 0; i < num_permitted_opens; i++)
2694 if (permitted_opens[i].host_to_connect != NULL &&
2695 permitted_opens[i].port_to_connect == port &&
2696 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2701 logit("Received request to connect to host %.100s port %d, "
2702 "but the request was denied.", host, port);
2705 return connect_to(host, port);
2709 channel_send_window_changes(void)
2714 for (i = 0; i < channels_alloc; i++) {
2715 if (channels[i] == NULL || !channels[i]->client_tty ||
2716 channels[i]->type != SSH_CHANNEL_OPEN)
2718 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2720 channel_request_start(i, "window-change", 0);
2721 packet_put_int(ws.ws_col);
2722 packet_put_int(ws.ws_row);
2723 packet_put_int(ws.ws_xpixel);
2724 packet_put_int(ws.ws_ypixel);
2729 /* -- X11 forwarding */
2732 * Creates an internet domain socket for listening for X11 connections.
2733 * Returns 0 and a suitable display number for the DISPLAY variable
2734 * stored in display_numberp , or -1 if an error occurs.
2737 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2738 int single_connection, u_int *display_numberp, int **chanids)
2741 int display_number, sock;
2743 struct addrinfo hints, *ai, *aitop;
2744 char strport[NI_MAXSERV];
2745 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2747 if (chanids == NULL)
2750 for (display_number = x11_display_offset;
2751 display_number < MAX_DISPLAYS;
2753 port = 6000 + display_number;
2754 memset(&hints, 0, sizeof(hints));
2755 hints.ai_family = IPv4or6;
2756 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2757 hints.ai_socktype = SOCK_STREAM;
2758 snprintf(strport, sizeof strport, "%d", port);
2759 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2760 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2763 for (ai = aitop; ai; ai = ai->ai_next) {
2764 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2766 sock = socket(ai->ai_family, ai->ai_socktype,
2769 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2770 error("socket: %.100s", strerror(errno));
2771 freeaddrinfo(aitop);
2774 debug("x11_create_display_inet: Socket family %d not supported",
2780 if (ai->ai_family == AF_INET6) {
2782 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2783 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2786 channel_set_reuseaddr(sock);
2787 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2788 debug2("bind port %d: %.100s", port, strerror(errno));
2794 for (n = 0; n < num_socks; n++) {
2800 socks[num_socks++] = sock;
2801 #ifndef DONT_TRY_OTHER_AF
2802 if (num_socks == NUM_SOCKS)
2805 if (x11_use_localhost) {
2806 if (num_socks == NUM_SOCKS)
2813 freeaddrinfo(aitop);
2817 if (display_number >= MAX_DISPLAYS) {
2818 error("Failed to allocate internet-domain X11 display socket.");
2821 /* Start listening for connections on the socket. */
2822 for (n = 0; n < num_socks; n++) {
2824 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2825 error("listen: %.100s", strerror(errno));
2831 /* Allocate a channel for each socket. */
2832 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
2833 for (n = 0; n < num_socks; n++) {
2835 nc = channel_new("x11 listener",
2836 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2837 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2838 0, "X11 inet listener", 1);
2839 nc->single_connection = single_connection;
2840 (*chanids)[n] = nc->self;
2844 /* Return the display number for the DISPLAY environment variable. */
2845 *display_numberp = display_number;
2850 connect_local_xsocket(u_int dnr)
2853 struct sockaddr_un addr;
2855 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2857 error("socket: %.100s", strerror(errno));
2858 memset(&addr, 0, sizeof(addr));
2859 addr.sun_family = AF_UNIX;
2860 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2861 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2864 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2869 x11_connect_display(void)
2871 int display_number, sock = 0;
2872 const char *display;
2873 char buf[1024], *cp;
2874 struct addrinfo hints, *ai, *aitop;
2875 char strport[NI_MAXSERV];
2878 /* Try to open a socket for the local X server. */
2879 display = getenv("DISPLAY");
2881 error("DISPLAY not set.");
2885 * Now we decode the value of the DISPLAY variable and make a
2886 * connection to the real X server.
2890 * Check if it is a unix domain socket. Unix domain displays are in
2891 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2893 if (strncmp(display, "unix:", 5) == 0 ||
2894 display[0] == ':') {
2895 /* Connect to the unix domain socket. */
2896 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2897 error("Could not parse display number from DISPLAY: %.100s",
2901 /* Create a socket. */
2902 sock = connect_local_xsocket(display_number);
2906 /* OK, we now have a connection to the display. */
2910 * Connect to an inet socket. The DISPLAY value is supposedly
2911 * hostname:d[.s], where hostname may also be numeric IP address.
2913 strlcpy(buf, display, sizeof(buf));
2914 cp = strchr(buf, ':');
2916 error("Could not find ':' in DISPLAY: %.100s", display);
2920 /* buf now contains the host name. But first we parse the display number. */
2921 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2922 error("Could not parse display number from DISPLAY: %.100s",
2927 /* Look up the host address */
2928 memset(&hints, 0, sizeof(hints));
2929 hints.ai_family = IPv4or6;
2930 hints.ai_socktype = SOCK_STREAM;
2931 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2932 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2933 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2936 for (ai = aitop; ai; ai = ai->ai_next) {
2937 /* Create a socket. */
2938 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2940 debug2("socket: %.100s", strerror(errno));
2943 /* Connect it to the display. */
2944 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2945 debug2("connect %.100s port %d: %.100s", buf,
2946 6000 + display_number, strerror(errno));
2953 freeaddrinfo(aitop);
2955 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2964 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2965 * the remote channel number. We should do whatever we want, and respond
2966 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2970 x11_input_open(int type, u_int32_t seq, void *ctxt)
2973 int remote_id, sock = 0;
2976 debug("Received X11 open request.");
2978 remote_id = packet_get_int();
2980 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2981 remote_host = packet_get_string(NULL);
2983 remote_host = xstrdup("unknown (remote did not supply name)");
2987 /* Obtain a connection to the real X display. */
2988 sock = x11_connect_display();
2990 /* Allocate a channel for this connection. */
2991 c = channel_new("connected x11 socket",
2992 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2994 c->remote_id = remote_id;
2999 /* Send refusal to the remote host. */
3000 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3001 packet_put_int(remote_id);
3003 /* Send a confirmation to the remote host. */
3004 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3005 packet_put_int(remote_id);
3006 packet_put_int(c->self);
3011 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3013 deny_input_open(int type, u_int32_t seq, void *ctxt)
3015 int rchan = packet_get_int();
3018 case SSH_SMSG_AGENT_OPEN:
3019 error("Warning: ssh server tried agent forwarding.");
3021 case SSH_SMSG_X11_OPEN:
3022 error("Warning: ssh server tried X11 forwarding.");
3025 error("deny_input_open: type %d", type);
3028 error("Warning: this is probably a break-in attempt by a malicious server.");
3029 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3030 packet_put_int(rchan);
3035 * Requests forwarding of X11 connections, generates fake authentication
3036 * data, and enables authentication spoofing.
3037 * This should be called in the client only.
3040 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3041 const char *proto, const char *data)
3043 u_int data_len = (u_int) strlen(data) / 2;
3050 if (x11_saved_display == NULL)
3051 x11_saved_display = xstrdup(disp);
3052 else if (strcmp(disp, x11_saved_display) != 0) {
3053 error("x11_request_forwarding_with_spoofing: different "
3054 "$DISPLAY already forwarded");
3060 cp = strchr(disp, ':');
3062 cp = strchr(cp, '.');
3064 screen_number = atoi(cp + 1);
3068 if (x11_saved_proto == NULL) {
3069 /* Save protocol name. */
3070 x11_saved_proto = xstrdup(proto);
3072 * Extract real authentication data and generate fake data
3073 * of the same length.
3075 x11_saved_data = xmalloc(data_len);
3076 x11_fake_data = xmalloc(data_len);
3077 for (i = 0; i < data_len; i++) {
3078 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3079 fatal("x11_request_forwarding: bad "
3080 "authentication data: %.100s", data);
3083 x11_saved_data[i] = value;
3084 x11_fake_data[i] = rnd & 0xff;
3087 x11_saved_data_len = data_len;
3088 x11_fake_data_len = data_len;
3091 /* Convert the fake data into hex. */
3092 new_data = tohex(x11_fake_data, data_len);
3094 /* Send the request packet. */
3096 channel_request_start(client_session_id, "x11-req", 0);
3097 packet_put_char(0); /* XXX bool single connection */
3099 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3101 packet_put_cstring(proto);
3102 packet_put_cstring(new_data);
3103 packet_put_int(screen_number);
3105 packet_write_wait();
3110 /* -- agent forwarding */
3112 /* Sends a message to the server to request authentication fd forwarding. */
3115 auth_request_forwarding(void)
3117 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3119 packet_write_wait();