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 1.226 2005/10/11 23:37:37 djm 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_lookup(int id)
149 if (id < 0 || (u_int)id >= channels_alloc) {
150 logit("channel_lookup: %d: bad id", id);
155 logit("channel_lookup: %d: bad id: channel free", id);
162 * Register filedescriptors for a channel, used when allocating a channel or
163 * when the channel consumer/producer is ready, e.g. shell exec'd
167 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
168 int extusage, int nonblock)
170 /* Update the maximum file descriptor value. */
171 channel_max_fd = MAX(channel_max_fd, rfd);
172 channel_max_fd = MAX(channel_max_fd, wfd);
173 channel_max_fd = MAX(channel_max_fd, efd);
175 /* XXX set close-on-exec -markus */
179 c->sock = (rfd == wfd) ? rfd : -1;
180 c->ctl_fd = -1; /* XXX: set elsewhere */
182 c->extended_usage = extusage;
184 /* XXX ugly hack: nonblock is only set by the server */
185 if (nonblock && isatty(c->rfd)) {
186 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
188 if (!isatty(c->wfd)) {
189 error("channel %d: wfd %d is not a tty?",
195 c->wfd_isatty = isatty(c->wfd);
197 /* enable nonblocking mode */
209 * Allocate a new channel object and set its type and socket. This will cause
210 * remote_name to be freed.
214 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
215 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
221 /* Do initial allocation if this is the first call. */
222 if (channels_alloc == 0) {
224 channels = xmalloc(channels_alloc * sizeof(Channel *));
225 for (i = 0; i < channels_alloc; i++)
228 /* Try to find a free slot where to put the new channel. */
229 for (found = -1, i = 0; i < channels_alloc; i++)
230 if (channels[i] == NULL) {
231 /* Found a free slot. */
236 /* There are no free slots. Take last+1 slot and expand the array. */
237 found = channels_alloc;
238 if (channels_alloc > 10000)
239 fatal("channel_new: internal error: channels_alloc %d "
240 "too big.", channels_alloc);
241 channels = xrealloc(channels,
242 (channels_alloc + 10) * sizeof(Channel *));
243 channels_alloc += 10;
244 debug2("channel: expanding %d", channels_alloc);
245 for (i = found; i < channels_alloc; i++)
248 /* Initialize and return new channel. */
249 c = channels[found] = xmalloc(sizeof(Channel));
250 memset(c, 0, sizeof(Channel));
251 buffer_init(&c->input);
252 buffer_init(&c->output);
253 buffer_init(&c->extended);
254 c->ostate = CHAN_OUTPUT_OPEN;
255 c->istate = CHAN_INPUT_OPEN;
257 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
261 c->local_window = window;
262 c->local_window_max = window;
263 c->local_consumed = 0;
264 c->local_maxpacket = maxpack;
266 c->remote_name = xstrdup(remote_name);
267 c->remote_window = 0;
268 c->remote_maxpacket = 0;
270 c->single_connection = 0;
271 c->detach_user = NULL;
274 c->confirm_ctx = NULL;
275 c->input_filter = NULL;
276 debug("channel %d: new [%s]", found, remote_name);
281 channel_find_maxfd(void)
287 for (i = 0; i < channels_alloc; i++) {
290 max = MAX(max, c->rfd);
291 max = MAX(max, c->wfd);
292 max = MAX(max, c->efd);
299 channel_close_fd(int *fdp)
301 int ret = 0, fd = *fdp;
306 if (fd == channel_max_fd)
307 channel_max_fd = channel_find_maxfd();
312 /* Close all channel fd/socket. */
315 channel_close_fds(Channel *c)
317 debug3("channel %d: close_fds r %d w %d e %d c %d",
318 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
320 channel_close_fd(&c->sock);
321 channel_close_fd(&c->ctl_fd);
322 channel_close_fd(&c->rfd);
323 channel_close_fd(&c->wfd);
324 channel_close_fd(&c->efd);
327 /* Free the channel and close its fd/socket. */
330 channel_free(Channel *c)
335 for (n = 0, i = 0; i < channels_alloc; i++)
338 debug("channel %d: free: %s, nchannels %u", c->self,
339 c->remote_name ? c->remote_name : "???", n);
341 s = channel_open_message();
342 debug3("channel %d: status: %s", c->self, s);
346 shutdown(c->sock, SHUT_RDWR);
348 shutdown(c->ctl_fd, SHUT_RDWR);
349 channel_close_fds(c);
350 buffer_free(&c->input);
351 buffer_free(&c->output);
352 buffer_free(&c->extended);
353 if (c->remote_name) {
354 xfree(c->remote_name);
355 c->remote_name = NULL;
357 channels[c->self] = NULL;
362 channel_free_all(void)
366 for (i = 0; i < channels_alloc; i++)
367 if (channels[i] != NULL)
368 channel_free(channels[i]);
372 * Closes the sockets/fds of all channels. This is used to close extra file
373 * descriptors after a fork.
377 channel_close_all(void)
381 for (i = 0; i < channels_alloc; i++)
382 if (channels[i] != NULL)
383 channel_close_fds(channels[i]);
387 * Stop listening to channels.
391 channel_stop_listening(void)
396 for (i = 0; i < channels_alloc; i++) {
400 case SSH_CHANNEL_AUTH_SOCKET:
401 case SSH_CHANNEL_PORT_LISTENER:
402 case SSH_CHANNEL_RPORT_LISTENER:
403 case SSH_CHANNEL_X11_LISTENER:
404 channel_close_fd(&c->sock);
413 * Returns true if no channel has too much buffered data, and false if one or
414 * more channel is overfull.
418 channel_not_very_much_buffered_data(void)
423 for (i = 0; i < channels_alloc; i++) {
425 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
428 buffer_len(&c->input) > packet_get_maxsize()) {
429 debug2("channel %d: big input buffer %d",
430 c->self, buffer_len(&c->input));
434 if (buffer_len(&c->output) > packet_get_maxsize()) {
435 debug2("channel %d: big output buffer %u > %u",
436 c->self, buffer_len(&c->output),
437 packet_get_maxsize());
445 /* Returns true if any channel is still open. */
448 channel_still_open(void)
453 for (i = 0; i < channels_alloc; i++) {
458 case SSH_CHANNEL_X11_LISTENER:
459 case SSH_CHANNEL_PORT_LISTENER:
460 case SSH_CHANNEL_RPORT_LISTENER:
461 case SSH_CHANNEL_CLOSED:
462 case SSH_CHANNEL_AUTH_SOCKET:
463 case SSH_CHANNEL_DYNAMIC:
464 case SSH_CHANNEL_CONNECTING:
465 case SSH_CHANNEL_ZOMBIE:
467 case SSH_CHANNEL_LARVAL:
469 fatal("cannot happen: SSH_CHANNEL_LARVAL");
471 case SSH_CHANNEL_OPENING:
472 case SSH_CHANNEL_OPEN:
473 case SSH_CHANNEL_X11_OPEN:
475 case SSH_CHANNEL_INPUT_DRAINING:
476 case SSH_CHANNEL_OUTPUT_DRAINING:
478 fatal("cannot happen: OUT_DRAIN");
481 fatal("channel_still_open: bad channel type %d", c->type);
488 /* Returns the id of an open channel suitable for keepaliving */
491 channel_find_open(void)
496 for (i = 0; i < channels_alloc; i++) {
498 if (c == NULL || c->remote_id < 0)
501 case SSH_CHANNEL_CLOSED:
502 case SSH_CHANNEL_DYNAMIC:
503 case SSH_CHANNEL_X11_LISTENER:
504 case SSH_CHANNEL_PORT_LISTENER:
505 case SSH_CHANNEL_RPORT_LISTENER:
506 case SSH_CHANNEL_OPENING:
507 case SSH_CHANNEL_CONNECTING:
508 case SSH_CHANNEL_ZOMBIE:
510 case SSH_CHANNEL_LARVAL:
511 case SSH_CHANNEL_AUTH_SOCKET:
512 case SSH_CHANNEL_OPEN:
513 case SSH_CHANNEL_X11_OPEN:
515 case SSH_CHANNEL_INPUT_DRAINING:
516 case SSH_CHANNEL_OUTPUT_DRAINING:
518 fatal("cannot happen: OUT_DRAIN");
521 fatal("channel_find_open: bad channel type %d", c->type);
530 * Returns a message describing the currently open forwarded connections,
531 * suitable for sending to the client. The message contains crlf pairs for
536 channel_open_message(void)
543 buffer_init(&buffer);
544 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
545 buffer_append(&buffer, buf, strlen(buf));
546 for (i = 0; i < channels_alloc; i++) {
551 case SSH_CHANNEL_X11_LISTENER:
552 case SSH_CHANNEL_PORT_LISTENER:
553 case SSH_CHANNEL_RPORT_LISTENER:
554 case SSH_CHANNEL_CLOSED:
555 case SSH_CHANNEL_AUTH_SOCKET:
556 case SSH_CHANNEL_ZOMBIE:
558 case SSH_CHANNEL_LARVAL:
559 case SSH_CHANNEL_OPENING:
560 case SSH_CHANNEL_CONNECTING:
561 case SSH_CHANNEL_DYNAMIC:
562 case SSH_CHANNEL_OPEN:
563 case SSH_CHANNEL_X11_OPEN:
564 case SSH_CHANNEL_INPUT_DRAINING:
565 case SSH_CHANNEL_OUTPUT_DRAINING:
566 snprintf(buf, sizeof buf,
567 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
568 c->self, c->remote_name,
569 c->type, c->remote_id,
570 c->istate, buffer_len(&c->input),
571 c->ostate, buffer_len(&c->output),
572 c->rfd, c->wfd, c->ctl_fd);
573 buffer_append(&buffer, buf, strlen(buf));
576 fatal("channel_open_message: bad channel type %d", c->type);
580 buffer_append(&buffer, "\0", 1);
581 cp = xstrdup(buffer_ptr(&buffer));
582 buffer_free(&buffer);
587 channel_send_open(int id)
589 Channel *c = channel_lookup(id);
592 logit("channel_send_open: %d: bad id", id);
595 debug2("channel %d: send open", id);
596 packet_start(SSH2_MSG_CHANNEL_OPEN);
597 packet_put_cstring(c->ctype);
598 packet_put_int(c->self);
599 packet_put_int(c->local_window);
600 packet_put_int(c->local_maxpacket);
605 channel_request_start(int id, char *service, int wantconfirm)
607 Channel *c = channel_lookup(id);
610 logit("channel_request_start: %d: unknown channel id", id);
613 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
614 packet_start(SSH2_MSG_CHANNEL_REQUEST);
615 packet_put_int(c->remote_id);
616 packet_put_cstring(service);
617 packet_put_char(wantconfirm);
620 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
622 Channel *c = channel_lookup(id);
625 logit("channel_register_comfirm: %d: bad id", id);
629 c->confirm_ctx = ctx;
632 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
634 Channel *c = channel_lookup(id);
637 logit("channel_register_cleanup: %d: bad id", id);
641 c->detach_close = do_close;
644 channel_cancel_cleanup(int id)
646 Channel *c = channel_lookup(id);
649 logit("channel_cancel_cleanup: %d: bad id", id);
652 c->detach_user = NULL;
656 channel_register_filter(int id, channel_filter_fn *fn)
658 Channel *c = channel_lookup(id);
661 logit("channel_register_filter: %d: bad id", id);
664 c->input_filter = fn;
668 channel_set_fds(int id, int rfd, int wfd, int efd,
669 int extusage, int nonblock, u_int window_max)
671 Channel *c = channel_lookup(id);
673 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
674 fatal("channel_activate for non-larval channel %d.", id);
675 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
676 c->type = SSH_CHANNEL_OPEN;
677 c->local_window = c->local_window_max = window_max;
678 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
679 packet_put_int(c->remote_id);
680 packet_put_int(c->local_window);
685 * 'channel_pre*' are called just before select() to add any bits relevant to
686 * channels in the select bitmasks.
689 * 'channel_post*': perform any appropriate operations for channels which
690 * have events pending.
692 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
693 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
694 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
697 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
699 FD_SET(c->sock, readset);
703 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
705 debug3("channel %d: waiting for connection", c->self);
706 FD_SET(c->sock, writeset);
710 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
712 if (buffer_len(&c->input) < packet_get_maxsize())
713 FD_SET(c->sock, readset);
714 if (buffer_len(&c->output) > 0)
715 FD_SET(c->sock, writeset);
719 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
721 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
723 /* check buffer limits */
724 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
726 if (c->istate == CHAN_INPUT_OPEN &&
728 buffer_len(&c->input) < limit)
729 FD_SET(c->rfd, readset);
730 if (c->ostate == CHAN_OUTPUT_OPEN ||
731 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
732 if (buffer_len(&c->output) > 0) {
733 FD_SET(c->wfd, writeset);
734 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
735 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
736 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
737 c->self, c->efd, buffer_len(&c->extended));
742 /** XXX check close conditions, too */
743 if (compat20 && c->efd != -1) {
744 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
745 buffer_len(&c->extended) > 0)
746 FD_SET(c->efd, writeset);
747 else if (!(c->flags & CHAN_EOF_SENT) &&
748 c->extended_usage == CHAN_EXTENDED_READ &&
749 buffer_len(&c->extended) < c->remote_window)
750 FD_SET(c->efd, readset);
752 /* XXX: What about efd? races? */
753 if (compat20 && c->ctl_fd != -1 &&
754 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
755 FD_SET(c->ctl_fd, readset);
759 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
761 if (buffer_len(&c->input) == 0) {
762 packet_start(SSH_MSG_CHANNEL_CLOSE);
763 packet_put_int(c->remote_id);
765 c->type = SSH_CHANNEL_CLOSED;
766 debug2("channel %d: closing after input drain.", c->self);
771 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
773 if (buffer_len(&c->output) == 0)
776 FD_SET(c->sock, writeset);
780 * This is a special state for X11 authentication spoofing. An opened X11
781 * connection (when authentication spoofing is being done) remains in this
782 * state until the first packet has been completely read. The authentication
783 * data in that packet is then substituted by the real data if it matches the
784 * fake data, and the channel is put into normal mode.
785 * XXX All this happens at the client side.
786 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
789 x11_open_helper(Buffer *b)
792 u_int proto_len, data_len;
794 /* Check if the fixed size part of the packet is in buffer. */
795 if (buffer_len(b) < 12)
798 /* Parse the lengths of variable-length fields. */
800 if (ucp[0] == 0x42) { /* Byte order MSB first. */
801 proto_len = 256 * ucp[6] + ucp[7];
802 data_len = 256 * ucp[8] + ucp[9];
803 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
804 proto_len = ucp[6] + 256 * ucp[7];
805 data_len = ucp[8] + 256 * ucp[9];
807 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
812 /* Check if the whole packet is in buffer. */
814 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
817 /* Check if authentication protocol matches. */
818 if (proto_len != strlen(x11_saved_proto) ||
819 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
820 debug2("X11 connection uses different authentication protocol.");
823 /* Check if authentication data matches our fake data. */
824 if (data_len != x11_fake_data_len ||
825 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
826 x11_fake_data, x11_fake_data_len) != 0) {
827 debug2("X11 auth data does not match fake data.");
830 /* Check fake data length */
831 if (x11_fake_data_len != x11_saved_data_len) {
832 error("X11 fake_data_len %d != saved_data_len %d",
833 x11_fake_data_len, x11_saved_data_len);
837 * Received authentication protocol and data match
838 * our fake data. Substitute the fake data with real
841 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
842 x11_saved_data, x11_saved_data_len);
847 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
849 int ret = x11_open_helper(&c->output);
852 /* Start normal processing for the channel. */
853 c->type = SSH_CHANNEL_OPEN;
854 channel_pre_open_13(c, readset, writeset);
855 } else if (ret == -1) {
857 * We have received an X11 connection that has bad
858 * authentication information.
860 logit("X11 connection rejected because of wrong authentication.");
861 buffer_clear(&c->input);
862 buffer_clear(&c->output);
863 channel_close_fd(&c->sock);
865 c->type = SSH_CHANNEL_CLOSED;
866 packet_start(SSH_MSG_CHANNEL_CLOSE);
867 packet_put_int(c->remote_id);
873 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
875 int ret = x11_open_helper(&c->output);
877 /* c->force_drain = 1; */
880 c->type = SSH_CHANNEL_OPEN;
881 channel_pre_open(c, readset, writeset);
882 } else if (ret == -1) {
883 logit("X11 connection rejected because of wrong authentication.");
884 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
886 buffer_clear(&c->input);
888 buffer_clear(&c->output);
889 /* for proto v1, the peer will send an IEOF */
891 chan_write_failed(c);
893 c->type = SSH_CHANNEL_OPEN;
894 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
898 /* try to decode a socks4 header */
900 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
903 u_int len, have, i, found;
909 struct in_addr dest_addr;
912 debug2("channel %d: decode socks4", c->self);
914 have = buffer_len(&c->input);
915 len = sizeof(s4_req);
918 p = buffer_ptr(&c->input);
919 for (found = 0, i = len; i < have; i++) {
925 /* the peer is probably sending garbage */
926 debug("channel %d: decode socks4: too long",
933 buffer_get(&c->input, (char *)&s4_req.version, 1);
934 buffer_get(&c->input, (char *)&s4_req.command, 1);
935 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
936 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
937 have = buffer_len(&c->input);
938 p = buffer_ptr(&c->input);
940 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
942 fatal("channel %d: decode socks4: len %d > have %d",
944 strlcpy(username, p, sizeof(username));
945 buffer_consume(&c->input, len);
946 buffer_consume(&c->input, 1); /* trailing '\0' */
948 host = inet_ntoa(s4_req.dest_addr);
949 strlcpy(c->path, host, sizeof(c->path));
950 c->host_port = ntohs(s4_req.dest_port);
952 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
953 c->self, host, c->host_port, s4_req.command);
955 if (s4_req.command != 1) {
956 debug("channel %d: cannot handle: socks4 cn %d",
957 c->self, s4_req.command);
960 s4_rsp.version = 0; /* vn: 0 for reply */
961 s4_rsp.command = 90; /* cd: req granted */
962 s4_rsp.dest_port = 0; /* ignored */
963 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
964 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
968 /* try to decode a socks5 header */
969 #define SSH_SOCKS5_AUTHDONE 0x1000
970 #define SSH_SOCKS5_NOAUTH 0x00
971 #define SSH_SOCKS5_IPV4 0x01
972 #define SSH_SOCKS5_DOMAIN 0x03
973 #define SSH_SOCKS5_IPV6 0x04
974 #define SSH_SOCKS5_CONNECT 0x01
975 #define SSH_SOCKS5_SUCCESS 0x00
978 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
987 u_char *p, dest_addr[255+1];
988 u_int have, i, found, nmethods, addrlen, af;
990 debug2("channel %d: decode socks5", c->self);
991 p = buffer_ptr(&c->input);
994 have = buffer_len(&c->input);
995 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
996 /* format: ver | nmethods | methods */
1000 if (have < nmethods + 2)
1002 /* look for method: "NO AUTHENTICATION REQUIRED" */
1003 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1004 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1010 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1014 buffer_consume(&c->input, nmethods + 2);
1015 buffer_put_char(&c->output, 0x05); /* version */
1016 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1017 FD_SET(c->sock, writeset);
1018 c->flags |= SSH_SOCKS5_AUTHDONE;
1019 debug2("channel %d: socks5 auth done", c->self);
1020 return 0; /* need more */
1022 debug2("channel %d: socks5 post auth", c->self);
1023 if (have < sizeof(s5_req)+1)
1024 return 0; /* need more */
1025 memcpy((char *)&s5_req, p, sizeof(s5_req));
1026 if (s5_req.version != 0x05 ||
1027 s5_req.command != SSH_SOCKS5_CONNECT ||
1028 s5_req.reserved != 0x00) {
1029 debug2("channel %d: only socks5 connect supported", c->self);
1032 switch (s5_req.atyp){
1033 case SSH_SOCKS5_IPV4:
1037 case SSH_SOCKS5_DOMAIN:
1038 addrlen = p[sizeof(s5_req)];
1041 case SSH_SOCKS5_IPV6:
1046 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1049 if (have < 4 + addrlen + 2)
1051 buffer_consume(&c->input, sizeof(s5_req));
1052 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1053 buffer_consume(&c->input, 1); /* host string length */
1054 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1055 buffer_get(&c->input, (char *)&dest_port, 2);
1056 dest_addr[addrlen] = '\0';
1057 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1058 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1059 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1061 c->host_port = ntohs(dest_port);
1063 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1064 c->self, c->path, c->host_port, s5_req.command);
1066 s5_rsp.version = 0x05;
1067 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1068 s5_rsp.reserved = 0; /* ignored */
1069 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1070 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1071 dest_port = 0; /* ignored */
1073 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1074 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1075 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1079 /* dynamic port forwarding */
1081 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1087 have = buffer_len(&c->input);
1089 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1090 /* buffer_dump(&c->input); */
1091 /* check if the fixed size part of the packet is in buffer. */
1094 FD_SET(c->sock, readset);
1097 /* try to guess the protocol */
1098 p = buffer_ptr(&c->input);
1101 ret = channel_decode_socks4(c, readset, writeset);
1104 ret = channel_decode_socks5(c, readset, writeset);
1112 } else if (ret == 0) {
1113 debug2("channel %d: pre_dynamic: need more", c->self);
1115 FD_SET(c->sock, readset);
1117 /* switch to the next state */
1118 c->type = SSH_CHANNEL_OPENING;
1119 port_open_helper(c, "direct-tcpip");
1123 /* This is our fake X11 server socket. */
1125 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1128 struct sockaddr addr;
1131 char buf[16384], *remote_ipaddr;
1134 if (FD_ISSET(c->sock, readset)) {
1135 debug("X11 connection requested.");
1136 addrlen = sizeof(addr);
1137 newsock = accept(c->sock, &addr, &addrlen);
1138 if (c->single_connection) {
1139 debug2("single_connection: closing X11 listener.");
1140 channel_close_fd(&c->sock);
1144 error("accept: %.100s", strerror(errno));
1147 set_nodelay(newsock);
1148 remote_ipaddr = get_peer_ipaddr(newsock);
1149 remote_port = get_peer_port(newsock);
1150 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1151 remote_ipaddr, remote_port);
1153 nc = channel_new("accepted x11 socket",
1154 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1155 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1157 packet_start(SSH2_MSG_CHANNEL_OPEN);
1158 packet_put_cstring("x11");
1159 packet_put_int(nc->self);
1160 packet_put_int(nc->local_window_max);
1161 packet_put_int(nc->local_maxpacket);
1162 /* originator ipaddr and port */
1163 packet_put_cstring(remote_ipaddr);
1164 if (datafellows & SSH_BUG_X11FWD) {
1165 debug2("ssh2 x11 bug compat mode");
1167 packet_put_int(remote_port);
1171 packet_start(SSH_SMSG_X11_OPEN);
1172 packet_put_int(nc->self);
1173 if (packet_get_protocol_flags() &
1174 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1175 packet_put_cstring(buf);
1178 xfree(remote_ipaddr);
1183 port_open_helper(Channel *c, char *rtype)
1187 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1188 int remote_port = get_peer_port(c->sock);
1190 direct = (strcmp(rtype, "direct-tcpip") == 0);
1192 snprintf(buf, sizeof buf,
1193 "%s: listening port %d for %.100s port %d, "
1194 "connect from %.200s port %d",
1195 rtype, c->listening_port, c->path, c->host_port,
1196 remote_ipaddr, remote_port);
1198 xfree(c->remote_name);
1199 c->remote_name = xstrdup(buf);
1202 packet_start(SSH2_MSG_CHANNEL_OPEN);
1203 packet_put_cstring(rtype);
1204 packet_put_int(c->self);
1205 packet_put_int(c->local_window_max);
1206 packet_put_int(c->local_maxpacket);
1208 /* target host, port */
1209 packet_put_cstring(c->path);
1210 packet_put_int(c->host_port);
1212 /* listen address, port */
1213 packet_put_cstring(c->path);
1214 packet_put_int(c->listening_port);
1216 /* originator host and port */
1217 packet_put_cstring(remote_ipaddr);
1218 packet_put_int((u_int)remote_port);
1221 packet_start(SSH_MSG_PORT_OPEN);
1222 packet_put_int(c->self);
1223 packet_put_cstring(c->path);
1224 packet_put_int(c->host_port);
1225 if (packet_get_protocol_flags() &
1226 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1227 packet_put_cstring(c->remote_name);
1230 xfree(remote_ipaddr);
1234 channel_set_reuseaddr(int fd)
1239 * Set socket options.
1240 * Allow local port reuse in TIME_WAIT.
1242 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1243 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1247 * This socket is listening for connections to a forwarded TCP/IP port.
1250 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1253 struct sockaddr addr;
1254 int newsock, nextstate;
1258 if (FD_ISSET(c->sock, readset)) {
1259 debug("Connection to port %d forwarding "
1260 "to %.100s port %d requested.",
1261 c->listening_port, c->path, c->host_port);
1263 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1264 nextstate = SSH_CHANNEL_OPENING;
1265 rtype = "forwarded-tcpip";
1267 if (c->host_port == 0) {
1268 nextstate = SSH_CHANNEL_DYNAMIC;
1269 rtype = "dynamic-tcpip";
1271 nextstate = SSH_CHANNEL_OPENING;
1272 rtype = "direct-tcpip";
1276 addrlen = sizeof(addr);
1277 newsock = accept(c->sock, &addr, &addrlen);
1279 error("accept: %.100s", strerror(errno));
1282 set_nodelay(newsock);
1283 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1284 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1285 nc->listening_port = c->listening_port;
1286 nc->host_port = c->host_port;
1287 strlcpy(nc->path, c->path, sizeof(nc->path));
1289 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1291 * do not call the channel_post handler until
1292 * this flag has been reset by a pre-handler.
1293 * otherwise the FD_ISSET calls might overflow
1297 port_open_helper(nc, rtype);
1303 * This is the authentication agent socket listening for connections from
1307 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1311 struct sockaddr addr;
1314 if (FD_ISSET(c->sock, readset)) {
1315 addrlen = sizeof(addr);
1316 newsock = accept(c->sock, &addr, &addrlen);
1318 error("accept from auth socket: %.100s", strerror(errno));
1321 nc = channel_new("accepted auth socket",
1322 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1323 c->local_window_max, c->local_maxpacket,
1324 0, "accepted auth socket", 1);
1326 packet_start(SSH2_MSG_CHANNEL_OPEN);
1327 packet_put_cstring("auth-agent@openssh.com");
1328 packet_put_int(nc->self);
1329 packet_put_int(c->local_window_max);
1330 packet_put_int(c->local_maxpacket);
1332 packet_start(SSH_SMSG_AGENT_OPEN);
1333 packet_put_int(nc->self);
1340 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1343 socklen_t sz = sizeof(err);
1345 if (FD_ISSET(c->sock, writeset)) {
1346 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1348 error("getsockopt SO_ERROR failed");
1351 debug("channel %d: connected", c->self);
1352 c->type = SSH_CHANNEL_OPEN;
1354 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1355 packet_put_int(c->remote_id);
1356 packet_put_int(c->self);
1357 packet_put_int(c->local_window);
1358 packet_put_int(c->local_maxpacket);
1360 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1361 packet_put_int(c->remote_id);
1362 packet_put_int(c->self);
1365 debug("channel %d: not connected: %s",
1366 c->self, strerror(err));
1368 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1369 packet_put_int(c->remote_id);
1370 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1371 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1372 packet_put_cstring(strerror(err));
1373 packet_put_cstring("");
1376 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1377 packet_put_int(c->remote_id);
1386 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1388 char buf[CHAN_RBUF];
1392 FD_ISSET(c->rfd, readset)) {
1393 len = read(c->rfd, buf, sizeof(buf));
1394 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1397 debug2("channel %d: read<=0 rfd %d len %d",
1398 c->self, c->rfd, len);
1399 if (c->type != SSH_CHANNEL_OPEN) {
1400 debug2("channel %d: not open", c->self);
1403 } else if (compat13) {
1404 buffer_clear(&c->output);
1405 c->type = SSH_CHANNEL_INPUT_DRAINING;
1406 debug2("channel %d: input draining.", c->self);
1408 chan_read_failed(c);
1412 if (c->input_filter != NULL) {
1413 if (c->input_filter(c, buf, len) == -1) {
1414 debug2("channel %d: filter stops", c->self);
1415 chan_read_failed(c);
1418 buffer_append(&c->input, buf, len);
1424 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1431 /* Send buffered output data to the socket. */
1433 FD_ISSET(c->wfd, writeset) &&
1434 buffer_len(&c->output) > 0) {
1435 data = buffer_ptr(&c->output);
1436 dlen = buffer_len(&c->output);
1438 /* XXX: Later AIX versions can't push as much data to tty */
1439 if (compat20 && c->wfd_isatty)
1440 dlen = MIN(dlen, 8*1024);
1442 len = write(c->wfd, data, dlen);
1443 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1446 if (c->type != SSH_CHANNEL_OPEN) {
1447 debug2("channel %d: not open", c->self);
1450 } else if (compat13) {
1451 buffer_clear(&c->output);
1452 debug2("channel %d: input draining.", c->self);
1453 c->type = SSH_CHANNEL_INPUT_DRAINING;
1455 chan_write_failed(c);
1459 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1460 if (tcgetattr(c->wfd, &tio) == 0 &&
1461 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1463 * Simulate echo to reduce the impact of
1464 * traffic analysis. We need to match the
1465 * size of a SSH2_MSG_CHANNEL_DATA message
1466 * (4 byte channel id + data)
1468 packet_send_ignore(4 + len);
1472 buffer_consume(&c->output, len);
1473 if (compat20 && len > 0) {
1474 c->local_consumed += len;
1480 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1482 char buf[CHAN_RBUF];
1485 /** XXX handle drain efd, too */
1487 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1488 FD_ISSET(c->efd, writeset) &&
1489 buffer_len(&c->extended) > 0) {
1490 len = write(c->efd, buffer_ptr(&c->extended),
1491 buffer_len(&c->extended));
1492 debug2("channel %d: written %d to efd %d",
1493 c->self, len, c->efd);
1494 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1497 debug2("channel %d: closing write-efd %d",
1499 channel_close_fd(&c->efd);
1501 buffer_consume(&c->extended, len);
1502 c->local_consumed += len;
1504 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1505 FD_ISSET(c->efd, readset)) {
1506 len = read(c->efd, buf, sizeof(buf));
1507 debug2("channel %d: read %d from efd %d",
1508 c->self, len, c->efd);
1509 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1512 debug2("channel %d: closing read-efd %d",
1514 channel_close_fd(&c->efd);
1516 buffer_append(&c->extended, buf, len);
1523 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1528 /* Monitor control fd to detect if the slave client exits */
1529 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1530 len = read(c->ctl_fd, buf, sizeof(buf));
1531 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1534 debug2("channel %d: ctl read<=0", c->self);
1535 if (c->type != SSH_CHANNEL_OPEN) {
1536 debug2("channel %d: not open", c->self);
1540 chan_read_failed(c);
1541 chan_write_failed(c);
1545 fatal("%s: unexpected data on ctl fd", __func__);
1550 channel_check_window(Channel *c)
1552 if (c->type == SSH_CHANNEL_OPEN &&
1553 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1554 c->local_window < c->local_window_max/2 &&
1555 c->local_consumed > 0) {
1556 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1557 packet_put_int(c->remote_id);
1558 packet_put_int(c->local_consumed);
1560 debug2("channel %d: window %d sent adjust %d",
1561 c->self, c->local_window,
1563 c->local_window += c->local_consumed;
1564 c->local_consumed = 0;
1570 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1574 channel_handle_rfd(c, readset, writeset);
1575 channel_handle_wfd(c, readset, writeset);
1578 channel_handle_efd(c, readset, writeset);
1579 channel_handle_ctl(c, readset, writeset);
1580 channel_check_window(c);
1584 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1588 /* Send buffered output data to the socket. */
1589 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1590 len = write(c->sock, buffer_ptr(&c->output),
1591 buffer_len(&c->output));
1593 buffer_clear(&c->output);
1595 buffer_consume(&c->output, len);
1600 channel_handler_init_20(void)
1602 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1603 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1604 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1605 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1606 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1607 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1608 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1609 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1611 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1612 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1613 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1614 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1615 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1616 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1617 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1621 channel_handler_init_13(void)
1623 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1624 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1625 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1626 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1627 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1628 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1629 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1630 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1631 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1633 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1634 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1635 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1636 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1637 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1638 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1639 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1643 channel_handler_init_15(void)
1645 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1646 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1647 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1648 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1649 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1650 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1651 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1653 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1654 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1655 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1656 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1657 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1658 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1662 channel_handler_init(void)
1666 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1667 channel_pre[i] = NULL;
1668 channel_post[i] = NULL;
1671 channel_handler_init_20();
1673 channel_handler_init_13();
1675 channel_handler_init_15();
1678 /* gc dead channels */
1680 channel_garbage_collect(Channel *c)
1684 if (c->detach_user != NULL) {
1685 if (!chan_is_dead(c, c->detach_close))
1687 debug2("channel %d: gc: notify user", c->self);
1688 c->detach_user(c->self, NULL);
1689 /* if we still have a callback */
1690 if (c->detach_user != NULL)
1692 debug2("channel %d: gc: user detached", c->self);
1694 if (!chan_is_dead(c, 1))
1696 debug2("channel %d: garbage collecting", c->self);
1701 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1703 static int did_init = 0;
1708 channel_handler_init();
1711 for (i = 0; i < channels_alloc; i++) {
1715 if (ftab[c->type] != NULL)
1716 (*ftab[c->type])(c, readset, writeset);
1717 channel_garbage_collect(c);
1722 * Allocate/update select bitmasks and add any bits relevant to channels in
1726 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1727 u_int *nallocp, int rekeying)
1731 n = MAX(*maxfdp, channel_max_fd);
1733 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1734 /* perhaps check sz < nalloc/2 and shrink? */
1735 if (*readsetp == NULL || sz > *nallocp) {
1736 *readsetp = xrealloc(*readsetp, sz);
1737 *writesetp = xrealloc(*writesetp, sz);
1741 memset(*readsetp, 0, sz);
1742 memset(*writesetp, 0, sz);
1745 channel_handler(channel_pre, *readsetp, *writesetp);
1749 * After select, perform any appropriate operations for channels which have
1753 channel_after_select(fd_set * readset, fd_set * writeset)
1755 channel_handler(channel_post, readset, writeset);
1759 /* If there is data to send to the connection, enqueue some of it now. */
1762 channel_output_poll(void)
1767 for (i = 0; i < channels_alloc; i++) {
1773 * We are only interested in channels that can have buffered
1777 if (c->type != SSH_CHANNEL_OPEN &&
1778 c->type != SSH_CHANNEL_INPUT_DRAINING)
1781 if (c->type != SSH_CHANNEL_OPEN)
1785 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1786 /* XXX is this true? */
1787 debug3("channel %d: will not send data after close", c->self);
1791 /* Get the amount of buffered data for this channel. */
1792 if ((c->istate == CHAN_INPUT_OPEN ||
1793 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1794 (len = buffer_len(&c->input)) > 0) {
1796 * Send some data for the other side over the secure
1800 if (len > c->remote_window)
1801 len = c->remote_window;
1802 if (len > c->remote_maxpacket)
1803 len = c->remote_maxpacket;
1805 if (packet_is_interactive()) {
1809 /* Keep the packets at reasonable size. */
1810 if (len > packet_get_maxsize()/2)
1811 len = packet_get_maxsize()/2;
1815 packet_start(compat20 ?
1816 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1817 packet_put_int(c->remote_id);
1818 packet_put_string(buffer_ptr(&c->input), len);
1820 buffer_consume(&c->input, len);
1821 c->remote_window -= len;
1823 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1825 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1827 * input-buffer is empty and read-socket shutdown:
1828 * tell peer, that we will not send more data: send IEOF.
1829 * hack for extended data: delay EOF if EFD still in use.
1831 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1832 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1833 c->self, c->efd, buffer_len(&c->extended));
1837 /* Send extended data, i.e. stderr */
1839 !(c->flags & CHAN_EOF_SENT) &&
1840 c->remote_window > 0 &&
1841 (len = buffer_len(&c->extended)) > 0 &&
1842 c->extended_usage == CHAN_EXTENDED_READ) {
1843 debug2("channel %d: rwin %u elen %u euse %d",
1844 c->self, c->remote_window, buffer_len(&c->extended),
1846 if (len > c->remote_window)
1847 len = c->remote_window;
1848 if (len > c->remote_maxpacket)
1849 len = c->remote_maxpacket;
1850 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1851 packet_put_int(c->remote_id);
1852 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1853 packet_put_string(buffer_ptr(&c->extended), len);
1855 buffer_consume(&c->extended, len);
1856 c->remote_window -= len;
1857 debug2("channel %d: sent ext data %d", c->self, len);
1863 /* -- protocol input */
1866 channel_input_data(int type, u_int32_t seq, void *ctxt)
1873 /* Get the channel number and verify it. */
1874 id = packet_get_int();
1875 c = channel_lookup(id);
1877 packet_disconnect("Received data for nonexistent channel %d.", id);
1879 /* Ignore any data for non-open channels (might happen on close) */
1880 if (c->type != SSH_CHANNEL_OPEN &&
1881 c->type != SSH_CHANNEL_X11_OPEN)
1885 data = packet_get_string(&data_len);
1888 * Ignore data for protocol > 1.3 if output end is no longer open.
1889 * For protocol 2 the sending side is reducing its window as it sends
1890 * data, so we must 'fake' consumption of the data in order to ensure
1891 * that window updates are sent back. Otherwise the connection might
1894 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1896 c->local_window -= data_len;
1897 c->local_consumed += data_len;
1904 if (data_len > c->local_maxpacket) {
1905 logit("channel %d: rcvd big packet %d, maxpack %d",
1906 c->self, data_len, c->local_maxpacket);
1908 if (data_len > c->local_window) {
1909 logit("channel %d: rcvd too much data %d, win %d",
1910 c->self, data_len, c->local_window);
1914 c->local_window -= data_len;
1917 buffer_append(&c->output, data, data_len);
1922 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1926 u_int data_len, tcode;
1929 /* Get the channel number and verify it. */
1930 id = packet_get_int();
1931 c = channel_lookup(id);
1934 packet_disconnect("Received extended_data for bad channel %d.", id);
1935 if (c->type != SSH_CHANNEL_OPEN) {
1936 logit("channel %d: ext data for non open", id);
1939 if (c->flags & CHAN_EOF_RCVD) {
1940 if (datafellows & SSH_BUG_EXTEOF)
1941 debug("channel %d: accepting ext data after eof", id);
1943 packet_disconnect("Received extended_data after EOF "
1944 "on channel %d.", id);
1946 tcode = packet_get_int();
1948 c->extended_usage != CHAN_EXTENDED_WRITE ||
1949 tcode != SSH2_EXTENDED_DATA_STDERR) {
1950 logit("channel %d: bad ext data", c->self);
1953 data = packet_get_string(&data_len);
1955 if (data_len > c->local_window) {
1956 logit("channel %d: rcvd too much extended_data %d, win %d",
1957 c->self, data_len, c->local_window);
1961 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1962 c->local_window -= data_len;
1963 buffer_append(&c->extended, data, data_len);
1968 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1973 id = packet_get_int();
1975 c = channel_lookup(id);
1977 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1980 /* XXX force input close */
1981 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1982 debug("channel %d: FORCE input drain", c->self);
1983 c->istate = CHAN_INPUT_WAIT_DRAIN;
1984 if (buffer_len(&c->input) == 0)
1991 channel_input_close(int type, u_int32_t seq, void *ctxt)
1996 id = packet_get_int();
1998 c = channel_lookup(id);
2000 packet_disconnect("Received close for nonexistent channel %d.", id);
2003 * Send a confirmation that we have closed the channel and no more
2004 * data is coming for it.
2006 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2007 packet_put_int(c->remote_id);
2011 * If the channel is in closed state, we have sent a close request,
2012 * and the other side will eventually respond with a confirmation.
2013 * Thus, we cannot free the channel here, because then there would be
2014 * no-one to receive the confirmation. The channel gets freed when
2015 * the confirmation arrives.
2017 if (c->type != SSH_CHANNEL_CLOSED) {
2019 * Not a closed channel - mark it as draining, which will
2020 * cause it to be freed later.
2022 buffer_clear(&c->input);
2023 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2027 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2029 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2031 int id = packet_get_int();
2032 Channel *c = channel_lookup(id);
2036 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2037 chan_rcvd_oclose(c);
2041 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2043 int id = packet_get_int();
2044 Channel *c = channel_lookup(id);
2048 packet_disconnect("Received close confirmation for "
2049 "out-of-range channel %d.", id);
2050 if (c->type != SSH_CHANNEL_CLOSED)
2051 packet_disconnect("Received close confirmation for "
2052 "non-closed channel %d (type %d).", id, c->type);
2057 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2062 id = packet_get_int();
2063 c = channel_lookup(id);
2065 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2066 packet_disconnect("Received open confirmation for "
2067 "non-opening channel %d.", id);
2068 remote_id = packet_get_int();
2069 /* Record the remote channel number and mark that the channel is now open. */
2070 c->remote_id = remote_id;
2071 c->type = SSH_CHANNEL_OPEN;
2074 c->remote_window = packet_get_int();
2075 c->remote_maxpacket = packet_get_int();
2077 debug2("callback start");
2078 c->confirm(c->self, c->confirm_ctx);
2079 debug2("callback done");
2081 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2082 c->remote_window, c->remote_maxpacket);
2088 reason2txt(int reason)
2091 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2092 return "administratively prohibited";
2093 case SSH2_OPEN_CONNECT_FAILED:
2094 return "connect failed";
2095 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2096 return "unknown channel type";
2097 case SSH2_OPEN_RESOURCE_SHORTAGE:
2098 return "resource shortage";
2100 return "unknown reason";
2104 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2107 char *msg = NULL, *lang = NULL;
2110 id = packet_get_int();
2111 c = channel_lookup(id);
2113 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2114 packet_disconnect("Received open failure for "
2115 "non-opening channel %d.", id);
2117 reason = packet_get_int();
2118 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2119 msg = packet_get_string(NULL);
2120 lang = packet_get_string(NULL);
2122 logit("channel %d: open failed: %s%s%s", id,
2123 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2130 /* Free the channel. This will also close the socket. */
2135 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2144 /* Get the channel number and verify it. */
2145 id = packet_get_int();
2146 c = channel_lookup(id);
2148 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2149 logit("Received window adjust for "
2150 "non-open channel %d.", id);
2153 adjust = packet_get_int();
2155 debug2("channel %d: rcvd adjust %u", id, adjust);
2156 c->remote_window += adjust;
2160 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2164 char *host, *originator_string;
2165 int remote_id, sock = -1;
2167 remote_id = packet_get_int();
2168 host = packet_get_string(NULL);
2169 host_port = packet_get_int();
2171 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2172 originator_string = packet_get_string(NULL);
2174 originator_string = xstrdup("unknown (remote did not supply name)");
2177 sock = channel_connect_to(host, host_port);
2179 c = channel_new("connected socket",
2180 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2181 originator_string, 1);
2182 c->remote_id = remote_id;
2184 xfree(originator_string);
2186 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2187 packet_put_int(remote_id);
2194 /* -- tcp forwarding */
2197 channel_set_af(int af)
2203 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2204 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2207 int sock, r, success = 0, wildcard = 0, is_client;
2208 struct addrinfo hints, *ai, *aitop;
2209 const char *host, *addr;
2210 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2212 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2213 listen_addr : host_to_connect;
2214 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2217 error("No forward host name.");
2220 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2221 error("Forward host name too long.");
2226 * Determine whether or not a port forward listens to loopback,
2227 * specified address or wildcard. On the client, a specified bind
2228 * address will always override gateway_ports. On the server, a
2229 * gateway_ports of 1 (``yes'') will override the client's
2230 * specification and force a wildcard bind, whereas a value of 2
2231 * (``clientspecified'') will bind to whatever address the client
2234 * Special-case listen_addrs are:
2236 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2237 * "" (empty string), "*" -> wildcard v4/v6
2238 * "localhost" -> loopback v4/v6
2241 if (listen_addr == NULL) {
2242 /* No address specified: default to gateway_ports setting */
2245 } else if (gateway_ports || is_client) {
2246 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2247 strcmp(listen_addr, "0.0.0.0") == 0) ||
2248 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2249 (!is_client && gateway_ports == 1))
2251 else if (strcmp(listen_addr, "localhost") != 0)
2255 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2256 type, wildcard, (addr == NULL) ? "NULL" : addr);
2259 * getaddrinfo returns a loopback address if the hostname is
2260 * set to NULL and hints.ai_flags is not AI_PASSIVE
2262 memset(&hints, 0, sizeof(hints));
2263 hints.ai_family = IPv4or6;
2264 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2265 hints.ai_socktype = SOCK_STREAM;
2266 snprintf(strport, sizeof strport, "%d", listen_port);
2267 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2269 /* This really shouldn't happen */
2270 packet_disconnect("getaddrinfo: fatal error: %s",
2273 error("channel_setup_fwd_listener: "
2274 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2279 for (ai = aitop; ai; ai = ai->ai_next) {
2280 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2282 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2283 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2284 error("channel_setup_fwd_listener: getnameinfo failed");
2287 /* Create a port to listen for the host. */
2288 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2290 /* this is no error since kernel may not support ipv6 */
2291 verbose("socket: %.100s", strerror(errno));
2295 channel_set_reuseaddr(sock);
2297 debug("Local forwarding listening on %s port %s.", ntop, strport);
2299 /* Bind the socket to the address. */
2300 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2301 /* address can be in use ipv6 address is already bound */
2303 error("bind: %.100s", strerror(errno));
2305 verbose("bind: %.100s", strerror(errno));
2310 /* Start listening for connections on the socket. */
2311 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2312 error("listen: %.100s", strerror(errno));
2316 /* Allocate a channel number for the socket. */
2317 c = channel_new("port listener", type, sock, sock, -1,
2318 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2319 0, "port listener", 1);
2320 strlcpy(c->path, host, sizeof(c->path));
2321 c->host_port = port_to_connect;
2322 c->listening_port = listen_port;
2326 error("channel_setup_fwd_listener: cannot listen to port: %d",
2328 freeaddrinfo(aitop);
2333 channel_cancel_rport_listener(const char *host, u_short port)
2338 for (i = 0; i < channels_alloc; i++) {
2339 Channel *c = channels[i];
2341 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2342 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2343 c->listening_port == port) {
2344 debug2("%s: close channel %d", __func__, i);
2353 /* protocol local port fwd, used by ssh (and sshd in v1) */
2355 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2356 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2358 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2359 listen_host, listen_port, host_to_connect, port_to_connect,
2363 /* protocol v2 remote port fwd, used by sshd */
2365 channel_setup_remote_fwd_listener(const char *listen_address,
2366 u_short listen_port, int gateway_ports)
2368 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2369 listen_address, listen_port, NULL, 0, gateway_ports);
2373 * Initiate forwarding of connections to port "port" on remote host through
2374 * the secure channel to host:port from local side.
2378 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2379 const char *host_to_connect, u_short port_to_connect)
2381 int type, success = 0;
2383 /* Record locally that connection to this host/port is permitted. */
2384 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2385 fatal("channel_request_remote_forwarding: too many forwards");
2387 /* Send the forward request to the remote side. */
2389 const char *address_to_bind;
2390 if (listen_host == NULL)
2391 address_to_bind = "localhost";
2392 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2393 address_to_bind = "";
2395 address_to_bind = listen_host;
2397 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2398 packet_put_cstring("tcpip-forward");
2399 packet_put_char(1); /* boolean: want reply */
2400 packet_put_cstring(address_to_bind);
2401 packet_put_int(listen_port);
2403 packet_write_wait();
2404 /* Assume that server accepts the request */
2407 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2408 packet_put_int(listen_port);
2409 packet_put_cstring(host_to_connect);
2410 packet_put_int(port_to_connect);
2412 packet_write_wait();
2414 /* Wait for response from the remote side. */
2415 type = packet_read();
2417 case SSH_SMSG_SUCCESS:
2420 case SSH_SMSG_FAILURE:
2421 logit("Warning: Server denied remote port forwarding.");
2424 /* Unknown packet */
2425 packet_disconnect("Protocol error for port forward request:"
2426 "received packet type %d.", type);
2430 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2431 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2432 permitted_opens[num_permitted_opens].listen_port = listen_port;
2433 num_permitted_opens++;
2438 * Request cancellation of remote forwarding of connection host:port from
2442 channel_request_rforward_cancel(const char *host, u_short port)
2449 for (i = 0; i < num_permitted_opens; i++) {
2450 if (permitted_opens[i].host_to_connect != NULL &&
2451 permitted_opens[i].listen_port == port)
2454 if (i >= num_permitted_opens) {
2455 debug("%s: requested forward not found", __func__);
2458 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2459 packet_put_cstring("cancel-tcpip-forward");
2461 packet_put_cstring(host == NULL ? "" : host);
2462 packet_put_int(port);
2465 permitted_opens[i].listen_port = 0;
2466 permitted_opens[i].port_to_connect = 0;
2467 free(permitted_opens[i].host_to_connect);
2468 permitted_opens[i].host_to_connect = NULL;
2472 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2473 * listening for the port, and sends back a success reply (or disconnect
2474 * message if there was an error). This never returns if there was an error.
2478 channel_input_port_forward_request(int is_root, int gateway_ports)
2480 u_short port, host_port;
2483 /* Get arguments from the packet. */
2484 port = packet_get_int();
2485 hostname = packet_get_string(NULL);
2486 host_port = packet_get_int();
2490 * Check that an unprivileged user is not trying to forward a
2493 if (port < IPPORT_RESERVED && !is_root)
2495 "Requested forwarding of port %d but user is not root.",
2498 packet_disconnect("Dynamic forwarding denied.");
2501 /* Initiate forwarding */
2502 channel_setup_local_fwd_listener(NULL, port, hostname,
2503 host_port, gateway_ports);
2505 /* Free the argument string. */
2510 * Permits opening to any host/port if permitted_opens[] is empty. This is
2511 * usually called by the server, because the user could connect to any port
2512 * anyway, and the server has no way to know but to trust the client anyway.
2515 channel_permit_all_opens(void)
2517 if (num_permitted_opens == 0)
2518 all_opens_permitted = 1;
2522 channel_add_permitted_opens(char *host, int port)
2524 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2525 fatal("channel_request_remote_forwarding: too many forwards");
2526 debug("allow port forwarding to host %s port %d", host, port);
2528 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2529 permitted_opens[num_permitted_opens].port_to_connect = port;
2530 num_permitted_opens++;
2532 all_opens_permitted = 0;
2536 channel_clear_permitted_opens(void)
2540 for (i = 0; i < num_permitted_opens; i++)
2541 if (permitted_opens[i].host_to_connect != NULL)
2542 xfree(permitted_opens[i].host_to_connect);
2543 num_permitted_opens = 0;
2548 /* return socket to remote host, port */
2550 connect_to(const char *host, u_short port)
2552 struct addrinfo hints, *ai, *aitop;
2553 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2557 memset(&hints, 0, sizeof(hints));
2558 hints.ai_family = IPv4or6;
2559 hints.ai_socktype = SOCK_STREAM;
2560 snprintf(strport, sizeof strport, "%d", port);
2561 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2562 error("connect_to %.100s: unknown host (%s)", host,
2563 gai_strerror(gaierr));
2566 for (ai = aitop; ai; ai = ai->ai_next) {
2567 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2569 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2570 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2571 error("connect_to: getnameinfo failed");
2574 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2576 if (ai->ai_next == NULL)
2577 error("socket: %.100s", strerror(errno));
2579 verbose("socket: %.100s", strerror(errno));
2582 if (set_nonblock(sock) == -1)
2583 fatal("%s: set_nonblock(%d)", __func__, sock);
2584 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2585 errno != EINPROGRESS) {
2586 error("connect_to %.100s port %s: %.100s", ntop, strport,
2589 continue; /* fail -- try next */
2591 break; /* success */
2594 freeaddrinfo(aitop);
2596 error("connect_to %.100s port %d: failed.", host, port);
2605 channel_connect_by_listen_address(u_short listen_port)
2609 for (i = 0; i < num_permitted_opens; i++)
2610 if (permitted_opens[i].host_to_connect != NULL &&
2611 permitted_opens[i].listen_port == listen_port)
2613 permitted_opens[i].host_to_connect,
2614 permitted_opens[i].port_to_connect);
2615 error("WARNING: Server requests forwarding for unknown listen_port %d",
2620 /* Check if connecting to that port is permitted and connect. */
2622 channel_connect_to(const char *host, u_short port)
2626 permit = all_opens_permitted;
2628 for (i = 0; i < num_permitted_opens; i++)
2629 if (permitted_opens[i].host_to_connect != NULL &&
2630 permitted_opens[i].port_to_connect == port &&
2631 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2636 logit("Received request to connect to host %.100s port %d, "
2637 "but the request was denied.", host, port);
2640 return connect_to(host, port);
2644 channel_send_window_changes(void)
2649 for (i = 0; i < channels_alloc; i++) {
2650 if (channels[i] == NULL || !channels[i]->client_tty ||
2651 channels[i]->type != SSH_CHANNEL_OPEN)
2653 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2655 channel_request_start(i, "window-change", 0);
2656 packet_put_int(ws.ws_col);
2657 packet_put_int(ws.ws_row);
2658 packet_put_int(ws.ws_xpixel);
2659 packet_put_int(ws.ws_ypixel);
2664 /* -- X11 forwarding */
2667 * Creates an internet domain socket for listening for X11 connections.
2668 * Returns 0 and a suitable display number for the DISPLAY variable
2669 * stored in display_numberp , or -1 if an error occurs.
2672 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2673 int single_connection, u_int *display_numberp, int **chanids)
2676 int display_number, sock;
2678 struct addrinfo hints, *ai, *aitop;
2679 char strport[NI_MAXSERV];
2680 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2682 if (chanids == NULL)
2685 for (display_number = x11_display_offset;
2686 display_number < MAX_DISPLAYS;
2688 port = 6000 + display_number;
2689 memset(&hints, 0, sizeof(hints));
2690 hints.ai_family = IPv4or6;
2691 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2692 hints.ai_socktype = SOCK_STREAM;
2693 snprintf(strport, sizeof strport, "%d", port);
2694 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2695 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2698 for (ai = aitop; ai; ai = ai->ai_next) {
2699 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2701 sock = socket(ai->ai_family, ai->ai_socktype,
2704 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2705 error("socket: %.100s", strerror(errno));
2706 freeaddrinfo(aitop);
2709 debug("x11_create_display_inet: Socket family %d not supported",
2715 if (ai->ai_family == AF_INET6) {
2717 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2718 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2721 channel_set_reuseaddr(sock);
2722 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2723 debug2("bind port %d: %.100s", port, strerror(errno));
2729 for (n = 0; n < num_socks; n++) {
2735 socks[num_socks++] = sock;
2736 #ifndef DONT_TRY_OTHER_AF
2737 if (num_socks == NUM_SOCKS)
2740 if (x11_use_localhost) {
2741 if (num_socks == NUM_SOCKS)
2748 freeaddrinfo(aitop);
2752 if (display_number >= MAX_DISPLAYS) {
2753 error("Failed to allocate internet-domain X11 display socket.");
2756 /* Start listening for connections on the socket. */
2757 for (n = 0; n < num_socks; n++) {
2759 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2760 error("listen: %.100s", strerror(errno));
2766 /* Allocate a channel for each socket. */
2767 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
2768 for (n = 0; n < num_socks; n++) {
2770 nc = channel_new("x11 listener",
2771 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2772 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2773 0, "X11 inet listener", 1);
2774 nc->single_connection = single_connection;
2775 (*chanids)[n] = nc->self;
2779 /* Return the display number for the DISPLAY environment variable. */
2780 *display_numberp = display_number;
2785 connect_local_xsocket(u_int dnr)
2788 struct sockaddr_un addr;
2790 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2792 error("socket: %.100s", strerror(errno));
2793 memset(&addr, 0, sizeof(addr));
2794 addr.sun_family = AF_UNIX;
2795 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2796 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2799 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2804 x11_connect_display(void)
2806 int display_number, sock = 0;
2807 const char *display;
2808 char buf[1024], *cp;
2809 struct addrinfo hints, *ai, *aitop;
2810 char strport[NI_MAXSERV];
2813 /* Try to open a socket for the local X server. */
2814 display = getenv("DISPLAY");
2816 error("DISPLAY not set.");
2820 * Now we decode the value of the DISPLAY variable and make a
2821 * connection to the real X server.
2825 * Check if it is a unix domain socket. Unix domain displays are in
2826 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2828 if (strncmp(display, "unix:", 5) == 0 ||
2829 display[0] == ':') {
2830 /* Connect to the unix domain socket. */
2831 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2832 error("Could not parse display number from DISPLAY: %.100s",
2836 /* Create a socket. */
2837 sock = connect_local_xsocket(display_number);
2841 /* OK, we now have a connection to the display. */
2845 * Connect to an inet socket. The DISPLAY value is supposedly
2846 * hostname:d[.s], where hostname may also be numeric IP address.
2848 strlcpy(buf, display, sizeof(buf));
2849 cp = strchr(buf, ':');
2851 error("Could not find ':' in DISPLAY: %.100s", display);
2855 /* buf now contains the host name. But first we parse the display number. */
2856 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2857 error("Could not parse display number from DISPLAY: %.100s",
2862 /* Look up the host address */
2863 memset(&hints, 0, sizeof(hints));
2864 hints.ai_family = IPv4or6;
2865 hints.ai_socktype = SOCK_STREAM;
2866 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2867 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2868 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2871 for (ai = aitop; ai; ai = ai->ai_next) {
2872 /* Create a socket. */
2873 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2875 debug2("socket: %.100s", strerror(errno));
2878 /* Connect it to the display. */
2879 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2880 debug2("connect %.100s port %d: %.100s", buf,
2881 6000 + display_number, strerror(errno));
2888 freeaddrinfo(aitop);
2890 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2899 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2900 * the remote channel number. We should do whatever we want, and respond
2901 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2905 x11_input_open(int type, u_int32_t seq, void *ctxt)
2908 int remote_id, sock = 0;
2911 debug("Received X11 open request.");
2913 remote_id = packet_get_int();
2915 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2916 remote_host = packet_get_string(NULL);
2918 remote_host = xstrdup("unknown (remote did not supply name)");
2922 /* Obtain a connection to the real X display. */
2923 sock = x11_connect_display();
2925 /* Allocate a channel for this connection. */
2926 c = channel_new("connected x11 socket",
2927 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2929 c->remote_id = remote_id;
2934 /* Send refusal to the remote host. */
2935 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2936 packet_put_int(remote_id);
2938 /* Send a confirmation to the remote host. */
2939 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2940 packet_put_int(remote_id);
2941 packet_put_int(c->self);
2946 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2948 deny_input_open(int type, u_int32_t seq, void *ctxt)
2950 int rchan = packet_get_int();
2953 case SSH_SMSG_AGENT_OPEN:
2954 error("Warning: ssh server tried agent forwarding.");
2956 case SSH_SMSG_X11_OPEN:
2957 error("Warning: ssh server tried X11 forwarding.");
2960 error("deny_input_open: type %d", type);
2963 error("Warning: this is probably a break in attempt by a malicious server.");
2964 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2965 packet_put_int(rchan);
2970 * Requests forwarding of X11 connections, generates fake authentication
2971 * data, and enables authentication spoofing.
2972 * This should be called in the client only.
2975 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
2976 const char *proto, const char *data)
2978 u_int data_len = (u_int) strlen(data) / 2;
2985 if (x11_saved_display == NULL)
2986 x11_saved_display = xstrdup(disp);
2987 else if (strcmp(disp, x11_saved_display) != 0) {
2988 error("x11_request_forwarding_with_spoofing: different "
2989 "$DISPLAY already forwarded");
2995 cp = strchr(disp, ':');
2997 cp = strchr(cp, '.');
2999 screen_number = atoi(cp + 1);
3003 if (x11_saved_proto == NULL) {
3004 /* Save protocol name. */
3005 x11_saved_proto = xstrdup(proto);
3007 * Extract real authentication data and generate fake data
3008 * of the same length.
3010 x11_saved_data = xmalloc(data_len);
3011 x11_fake_data = xmalloc(data_len);
3012 for (i = 0; i < data_len; i++) {
3013 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3014 fatal("x11_request_forwarding: bad "
3015 "authentication data: %.100s", data);
3018 x11_saved_data[i] = value;
3019 x11_fake_data[i] = rnd & 0xff;
3022 x11_saved_data_len = data_len;
3023 x11_fake_data_len = data_len;
3026 /* Convert the fake data into hex. */
3027 new_data = tohex(x11_fake_data, data_len);
3029 /* Send the request packet. */
3031 channel_request_start(client_session_id, "x11-req", 0);
3032 packet_put_char(0); /* XXX bool single connection */
3034 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3036 packet_put_cstring(proto);
3037 packet_put_cstring(new_data);
3038 packet_put_int(screen_number);
3040 packet_write_wait();
3045 /* -- agent forwarding */
3047 /* Sends a message to the server to request authentication fd forwarding. */
3050 auth_request_forwarding(void)
3052 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3054 packet_write_wait();