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 1.225 2005/10/10 10:23:08 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 * This socket is listening for connections to a forwarded TCP/IP port.
1237 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1240 struct sockaddr addr;
1241 int newsock, nextstate;
1245 if (FD_ISSET(c->sock, readset)) {
1246 debug("Connection to port %d forwarding "
1247 "to %.100s port %d requested.",
1248 c->listening_port, c->path, c->host_port);
1250 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1251 nextstate = SSH_CHANNEL_OPENING;
1252 rtype = "forwarded-tcpip";
1254 if (c->host_port == 0) {
1255 nextstate = SSH_CHANNEL_DYNAMIC;
1256 rtype = "dynamic-tcpip";
1258 nextstate = SSH_CHANNEL_OPENING;
1259 rtype = "direct-tcpip";
1263 addrlen = sizeof(addr);
1264 newsock = accept(c->sock, &addr, &addrlen);
1266 error("accept: %.100s", strerror(errno));
1269 set_nodelay(newsock);
1270 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1271 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1272 nc->listening_port = c->listening_port;
1273 nc->host_port = c->host_port;
1274 strlcpy(nc->path, c->path, sizeof(nc->path));
1276 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1278 * do not call the channel_post handler until
1279 * this flag has been reset by a pre-handler.
1280 * otherwise the FD_ISSET calls might overflow
1284 port_open_helper(nc, rtype);
1290 * This is the authentication agent socket listening for connections from
1294 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1298 struct sockaddr addr;
1301 if (FD_ISSET(c->sock, readset)) {
1302 addrlen = sizeof(addr);
1303 newsock = accept(c->sock, &addr, &addrlen);
1305 error("accept from auth socket: %.100s", strerror(errno));
1308 nc = channel_new("accepted auth socket",
1309 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1310 c->local_window_max, c->local_maxpacket,
1311 0, "accepted auth socket", 1);
1313 packet_start(SSH2_MSG_CHANNEL_OPEN);
1314 packet_put_cstring("auth-agent@openssh.com");
1315 packet_put_int(nc->self);
1316 packet_put_int(c->local_window_max);
1317 packet_put_int(c->local_maxpacket);
1319 packet_start(SSH_SMSG_AGENT_OPEN);
1320 packet_put_int(nc->self);
1327 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1330 socklen_t sz = sizeof(err);
1332 if (FD_ISSET(c->sock, writeset)) {
1333 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1335 error("getsockopt SO_ERROR failed");
1338 debug("channel %d: connected", c->self);
1339 c->type = SSH_CHANNEL_OPEN;
1341 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1342 packet_put_int(c->remote_id);
1343 packet_put_int(c->self);
1344 packet_put_int(c->local_window);
1345 packet_put_int(c->local_maxpacket);
1347 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1348 packet_put_int(c->remote_id);
1349 packet_put_int(c->self);
1352 debug("channel %d: not connected: %s",
1353 c->self, strerror(err));
1355 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1356 packet_put_int(c->remote_id);
1357 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1358 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1359 packet_put_cstring(strerror(err));
1360 packet_put_cstring("");
1363 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1364 packet_put_int(c->remote_id);
1373 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1375 char buf[CHAN_RBUF];
1379 FD_ISSET(c->rfd, readset)) {
1380 len = read(c->rfd, buf, sizeof(buf));
1381 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1384 debug2("channel %d: read<=0 rfd %d len %d",
1385 c->self, c->rfd, len);
1386 if (c->type != SSH_CHANNEL_OPEN) {
1387 debug2("channel %d: not open", c->self);
1390 } else if (compat13) {
1391 buffer_clear(&c->output);
1392 c->type = SSH_CHANNEL_INPUT_DRAINING;
1393 debug2("channel %d: input draining.", c->self);
1395 chan_read_failed(c);
1399 if (c->input_filter != NULL) {
1400 if (c->input_filter(c, buf, len) == -1) {
1401 debug2("channel %d: filter stops", c->self);
1402 chan_read_failed(c);
1405 buffer_append(&c->input, buf, len);
1411 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1418 /* Send buffered output data to the socket. */
1420 FD_ISSET(c->wfd, writeset) &&
1421 buffer_len(&c->output) > 0) {
1422 data = buffer_ptr(&c->output);
1423 dlen = buffer_len(&c->output);
1425 /* XXX: Later AIX versions can't push as much data to tty */
1426 if (compat20 && c->wfd_isatty)
1427 dlen = MIN(dlen, 8*1024);
1429 len = write(c->wfd, data, dlen);
1430 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1433 if (c->type != SSH_CHANNEL_OPEN) {
1434 debug2("channel %d: not open", c->self);
1437 } else if (compat13) {
1438 buffer_clear(&c->output);
1439 debug2("channel %d: input draining.", c->self);
1440 c->type = SSH_CHANNEL_INPUT_DRAINING;
1442 chan_write_failed(c);
1446 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1447 if (tcgetattr(c->wfd, &tio) == 0 &&
1448 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1450 * Simulate echo to reduce the impact of
1451 * traffic analysis. We need to match the
1452 * size of a SSH2_MSG_CHANNEL_DATA message
1453 * (4 byte channel id + data)
1455 packet_send_ignore(4 + len);
1459 buffer_consume(&c->output, len);
1460 if (compat20 && len > 0) {
1461 c->local_consumed += len;
1467 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1469 char buf[CHAN_RBUF];
1472 /** XXX handle drain efd, too */
1474 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1475 FD_ISSET(c->efd, writeset) &&
1476 buffer_len(&c->extended) > 0) {
1477 len = write(c->efd, buffer_ptr(&c->extended),
1478 buffer_len(&c->extended));
1479 debug2("channel %d: written %d to efd %d",
1480 c->self, len, c->efd);
1481 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1484 debug2("channel %d: closing write-efd %d",
1486 channel_close_fd(&c->efd);
1488 buffer_consume(&c->extended, len);
1489 c->local_consumed += len;
1491 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1492 FD_ISSET(c->efd, readset)) {
1493 len = read(c->efd, buf, sizeof(buf));
1494 debug2("channel %d: read %d from efd %d",
1495 c->self, len, c->efd);
1496 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1499 debug2("channel %d: closing read-efd %d",
1501 channel_close_fd(&c->efd);
1503 buffer_append(&c->extended, buf, len);
1510 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1515 /* Monitor control fd to detect if the slave client exits */
1516 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1517 len = read(c->ctl_fd, buf, sizeof(buf));
1518 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1521 debug2("channel %d: ctl read<=0", c->self);
1522 if (c->type != SSH_CHANNEL_OPEN) {
1523 debug2("channel %d: not open", c->self);
1527 chan_read_failed(c);
1528 chan_write_failed(c);
1532 fatal("%s: unexpected data on ctl fd", __func__);
1537 channel_check_window(Channel *c)
1539 if (c->type == SSH_CHANNEL_OPEN &&
1540 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1541 c->local_window < c->local_window_max/2 &&
1542 c->local_consumed > 0) {
1543 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1544 packet_put_int(c->remote_id);
1545 packet_put_int(c->local_consumed);
1547 debug2("channel %d: window %d sent adjust %d",
1548 c->self, c->local_window,
1550 c->local_window += c->local_consumed;
1551 c->local_consumed = 0;
1557 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1561 channel_handle_rfd(c, readset, writeset);
1562 channel_handle_wfd(c, readset, writeset);
1565 channel_handle_efd(c, readset, writeset);
1566 channel_handle_ctl(c, readset, writeset);
1567 channel_check_window(c);
1571 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1575 /* Send buffered output data to the socket. */
1576 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1577 len = write(c->sock, buffer_ptr(&c->output),
1578 buffer_len(&c->output));
1580 buffer_clear(&c->output);
1582 buffer_consume(&c->output, len);
1587 channel_handler_init_20(void)
1589 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1590 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1591 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1592 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1593 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1594 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1595 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1596 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1598 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1599 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1600 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1601 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1602 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1603 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1604 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1608 channel_handler_init_13(void)
1610 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1611 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1612 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1613 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1614 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1615 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1616 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1617 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1618 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1620 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1621 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1622 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1623 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1624 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1625 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1626 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1630 channel_handler_init_15(void)
1632 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1633 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1634 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1635 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1636 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1637 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1638 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1640 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1641 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1642 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1643 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1644 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1645 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1649 channel_handler_init(void)
1653 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1654 channel_pre[i] = NULL;
1655 channel_post[i] = NULL;
1658 channel_handler_init_20();
1660 channel_handler_init_13();
1662 channel_handler_init_15();
1665 /* gc dead channels */
1667 channel_garbage_collect(Channel *c)
1671 if (c->detach_user != NULL) {
1672 if (!chan_is_dead(c, c->detach_close))
1674 debug2("channel %d: gc: notify user", c->self);
1675 c->detach_user(c->self, NULL);
1676 /* if we still have a callback */
1677 if (c->detach_user != NULL)
1679 debug2("channel %d: gc: user detached", c->self);
1681 if (!chan_is_dead(c, 1))
1683 debug2("channel %d: garbage collecting", c->self);
1688 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1690 static int did_init = 0;
1695 channel_handler_init();
1698 for (i = 0; i < channels_alloc; i++) {
1702 if (ftab[c->type] != NULL)
1703 (*ftab[c->type])(c, readset, writeset);
1704 channel_garbage_collect(c);
1709 * Allocate/update select bitmasks and add any bits relevant to channels in
1713 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1714 u_int *nallocp, int rekeying)
1718 n = MAX(*maxfdp, channel_max_fd);
1720 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1721 /* perhaps check sz < nalloc/2 and shrink? */
1722 if (*readsetp == NULL || sz > *nallocp) {
1723 *readsetp = xrealloc(*readsetp, sz);
1724 *writesetp = xrealloc(*writesetp, sz);
1728 memset(*readsetp, 0, sz);
1729 memset(*writesetp, 0, sz);
1732 channel_handler(channel_pre, *readsetp, *writesetp);
1736 * After select, perform any appropriate operations for channels which have
1740 channel_after_select(fd_set * readset, fd_set * writeset)
1742 channel_handler(channel_post, readset, writeset);
1746 /* If there is data to send to the connection, enqueue some of it now. */
1749 channel_output_poll(void)
1754 for (i = 0; i < channels_alloc; i++) {
1760 * We are only interested in channels that can have buffered
1764 if (c->type != SSH_CHANNEL_OPEN &&
1765 c->type != SSH_CHANNEL_INPUT_DRAINING)
1768 if (c->type != SSH_CHANNEL_OPEN)
1772 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1773 /* XXX is this true? */
1774 debug3("channel %d: will not send data after close", c->self);
1778 /* Get the amount of buffered data for this channel. */
1779 if ((c->istate == CHAN_INPUT_OPEN ||
1780 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1781 (len = buffer_len(&c->input)) > 0) {
1783 * Send some data for the other side over the secure
1787 if (len > c->remote_window)
1788 len = c->remote_window;
1789 if (len > c->remote_maxpacket)
1790 len = c->remote_maxpacket;
1792 if (packet_is_interactive()) {
1796 /* Keep the packets at reasonable size. */
1797 if (len > packet_get_maxsize()/2)
1798 len = packet_get_maxsize()/2;
1802 packet_start(compat20 ?
1803 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1804 packet_put_int(c->remote_id);
1805 packet_put_string(buffer_ptr(&c->input), len);
1807 buffer_consume(&c->input, len);
1808 c->remote_window -= len;
1810 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1812 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1814 * input-buffer is empty and read-socket shutdown:
1815 * tell peer, that we will not send more data: send IEOF.
1816 * hack for extended data: delay EOF if EFD still in use.
1818 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1819 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1820 c->self, c->efd, buffer_len(&c->extended));
1824 /* Send extended data, i.e. stderr */
1826 !(c->flags & CHAN_EOF_SENT) &&
1827 c->remote_window > 0 &&
1828 (len = buffer_len(&c->extended)) > 0 &&
1829 c->extended_usage == CHAN_EXTENDED_READ) {
1830 debug2("channel %d: rwin %u elen %u euse %d",
1831 c->self, c->remote_window, buffer_len(&c->extended),
1833 if (len > c->remote_window)
1834 len = c->remote_window;
1835 if (len > c->remote_maxpacket)
1836 len = c->remote_maxpacket;
1837 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1838 packet_put_int(c->remote_id);
1839 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1840 packet_put_string(buffer_ptr(&c->extended), len);
1842 buffer_consume(&c->extended, len);
1843 c->remote_window -= len;
1844 debug2("channel %d: sent ext data %d", c->self, len);
1850 /* -- protocol input */
1853 channel_input_data(int type, u_int32_t seq, void *ctxt)
1860 /* Get the channel number and verify it. */
1861 id = packet_get_int();
1862 c = channel_lookup(id);
1864 packet_disconnect("Received data for nonexistent channel %d.", id);
1866 /* Ignore any data for non-open channels (might happen on close) */
1867 if (c->type != SSH_CHANNEL_OPEN &&
1868 c->type != SSH_CHANNEL_X11_OPEN)
1872 data = packet_get_string(&data_len);
1875 * Ignore data for protocol > 1.3 if output end is no longer open.
1876 * For protocol 2 the sending side is reducing its window as it sends
1877 * data, so we must 'fake' consumption of the data in order to ensure
1878 * that window updates are sent back. Otherwise the connection might
1881 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1883 c->local_window -= data_len;
1884 c->local_consumed += data_len;
1891 if (data_len > c->local_maxpacket) {
1892 logit("channel %d: rcvd big packet %d, maxpack %d",
1893 c->self, data_len, c->local_maxpacket);
1895 if (data_len > c->local_window) {
1896 logit("channel %d: rcvd too much data %d, win %d",
1897 c->self, data_len, c->local_window);
1901 c->local_window -= data_len;
1904 buffer_append(&c->output, data, data_len);
1909 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1913 u_int data_len, tcode;
1916 /* Get the channel number and verify it. */
1917 id = packet_get_int();
1918 c = channel_lookup(id);
1921 packet_disconnect("Received extended_data for bad channel %d.", id);
1922 if (c->type != SSH_CHANNEL_OPEN) {
1923 logit("channel %d: ext data for non open", id);
1926 if (c->flags & CHAN_EOF_RCVD) {
1927 if (datafellows & SSH_BUG_EXTEOF)
1928 debug("channel %d: accepting ext data after eof", id);
1930 packet_disconnect("Received extended_data after EOF "
1931 "on channel %d.", id);
1933 tcode = packet_get_int();
1935 c->extended_usage != CHAN_EXTENDED_WRITE ||
1936 tcode != SSH2_EXTENDED_DATA_STDERR) {
1937 logit("channel %d: bad ext data", c->self);
1940 data = packet_get_string(&data_len);
1942 if (data_len > c->local_window) {
1943 logit("channel %d: rcvd too much extended_data %d, win %d",
1944 c->self, data_len, c->local_window);
1948 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1949 c->local_window -= data_len;
1950 buffer_append(&c->extended, data, data_len);
1955 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1960 id = packet_get_int();
1962 c = channel_lookup(id);
1964 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1967 /* XXX force input close */
1968 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1969 debug("channel %d: FORCE input drain", c->self);
1970 c->istate = CHAN_INPUT_WAIT_DRAIN;
1971 if (buffer_len(&c->input) == 0)
1978 channel_input_close(int type, u_int32_t seq, void *ctxt)
1983 id = packet_get_int();
1985 c = channel_lookup(id);
1987 packet_disconnect("Received close for nonexistent channel %d.", id);
1990 * Send a confirmation that we have closed the channel and no more
1991 * data is coming for it.
1993 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1994 packet_put_int(c->remote_id);
1998 * If the channel is in closed state, we have sent a close request,
1999 * and the other side will eventually respond with a confirmation.
2000 * Thus, we cannot free the channel here, because then there would be
2001 * no-one to receive the confirmation. The channel gets freed when
2002 * the confirmation arrives.
2004 if (c->type != SSH_CHANNEL_CLOSED) {
2006 * Not a closed channel - mark it as draining, which will
2007 * cause it to be freed later.
2009 buffer_clear(&c->input);
2010 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2014 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2016 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2018 int id = packet_get_int();
2019 Channel *c = channel_lookup(id);
2023 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2024 chan_rcvd_oclose(c);
2028 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2030 int id = packet_get_int();
2031 Channel *c = channel_lookup(id);
2035 packet_disconnect("Received close confirmation for "
2036 "out-of-range channel %d.", id);
2037 if (c->type != SSH_CHANNEL_CLOSED)
2038 packet_disconnect("Received close confirmation for "
2039 "non-closed channel %d (type %d).", id, c->type);
2044 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2049 id = packet_get_int();
2050 c = channel_lookup(id);
2052 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2053 packet_disconnect("Received open confirmation for "
2054 "non-opening channel %d.", id);
2055 remote_id = packet_get_int();
2056 /* Record the remote channel number and mark that the channel is now open. */
2057 c->remote_id = remote_id;
2058 c->type = SSH_CHANNEL_OPEN;
2061 c->remote_window = packet_get_int();
2062 c->remote_maxpacket = packet_get_int();
2064 debug2("callback start");
2065 c->confirm(c->self, c->confirm_ctx);
2066 debug2("callback done");
2068 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2069 c->remote_window, c->remote_maxpacket);
2075 reason2txt(int reason)
2078 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2079 return "administratively prohibited";
2080 case SSH2_OPEN_CONNECT_FAILED:
2081 return "connect failed";
2082 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2083 return "unknown channel type";
2084 case SSH2_OPEN_RESOURCE_SHORTAGE:
2085 return "resource shortage";
2087 return "unknown reason";
2091 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2094 char *msg = NULL, *lang = NULL;
2097 id = packet_get_int();
2098 c = channel_lookup(id);
2100 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2101 packet_disconnect("Received open failure for "
2102 "non-opening channel %d.", id);
2104 reason = packet_get_int();
2105 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2106 msg = packet_get_string(NULL);
2107 lang = packet_get_string(NULL);
2109 logit("channel %d: open failed: %s%s%s", id,
2110 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2117 /* Free the channel. This will also close the socket. */
2122 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2131 /* Get the channel number and verify it. */
2132 id = packet_get_int();
2133 c = channel_lookup(id);
2135 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2136 logit("Received window adjust for "
2137 "non-open channel %d.", id);
2140 adjust = packet_get_int();
2142 debug2("channel %d: rcvd adjust %u", id, adjust);
2143 c->remote_window += adjust;
2147 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2151 char *host, *originator_string;
2152 int remote_id, sock = -1;
2154 remote_id = packet_get_int();
2155 host = packet_get_string(NULL);
2156 host_port = packet_get_int();
2158 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2159 originator_string = packet_get_string(NULL);
2161 originator_string = xstrdup("unknown (remote did not supply name)");
2164 sock = channel_connect_to(host, host_port);
2166 c = channel_new("connected socket",
2167 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2168 originator_string, 1);
2169 c->remote_id = remote_id;
2171 xfree(originator_string);
2173 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2174 packet_put_int(remote_id);
2181 /* -- tcp forwarding */
2184 channel_set_af(int af)
2190 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2191 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2194 int sock, r, success = 0, on = 1, wildcard = 0, is_client;
2195 struct addrinfo hints, *ai, *aitop;
2196 const char *host, *addr;
2197 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2199 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2200 listen_addr : host_to_connect;
2201 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2204 error("No forward host name.");
2207 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2208 error("Forward host name too long.");
2213 * Determine whether or not a port forward listens to loopback,
2214 * specified address or wildcard. On the client, a specified bind
2215 * address will always override gateway_ports. On the server, a
2216 * gateway_ports of 1 (``yes'') will override the client's
2217 * specification and force a wildcard bind, whereas a value of 2
2218 * (``clientspecified'') will bind to whatever address the client
2221 * Special-case listen_addrs are:
2223 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2224 * "" (empty string), "*" -> wildcard v4/v6
2225 * "localhost" -> loopback v4/v6
2228 if (listen_addr == NULL) {
2229 /* No address specified: default to gateway_ports setting */
2232 } else if (gateway_ports || is_client) {
2233 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2234 strcmp(listen_addr, "0.0.0.0") == 0) ||
2235 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2236 (!is_client && gateway_ports == 1))
2238 else if (strcmp(listen_addr, "localhost") != 0)
2242 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2243 type, wildcard, (addr == NULL) ? "NULL" : addr);
2246 * getaddrinfo returns a loopback address if the hostname is
2247 * set to NULL and hints.ai_flags is not AI_PASSIVE
2249 memset(&hints, 0, sizeof(hints));
2250 hints.ai_family = IPv4or6;
2251 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2252 hints.ai_socktype = SOCK_STREAM;
2253 snprintf(strport, sizeof strport, "%d", listen_port);
2254 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2256 /* This really shouldn't happen */
2257 packet_disconnect("getaddrinfo: fatal error: %s",
2260 error("channel_setup_fwd_listener: "
2261 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2266 for (ai = aitop; ai; ai = ai->ai_next) {
2267 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2269 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2270 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2271 error("channel_setup_fwd_listener: getnameinfo failed");
2274 /* Create a port to listen for the host. */
2275 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2277 /* this is no error since kernel may not support ipv6 */
2278 verbose("socket: %.100s", strerror(errno));
2282 * Set socket options.
2283 * Allow local port reuse in TIME_WAIT.
2285 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on,
2287 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
2289 debug("Local forwarding listening on %s port %s.", ntop, strport);
2291 /* Bind the socket to the address. */
2292 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2293 /* address can be in use ipv6 address is already bound */
2295 error("bind: %.100s", strerror(errno));
2297 verbose("bind: %.100s", strerror(errno));
2302 /* Start listening for connections on the socket. */
2303 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2304 error("listen: %.100s", strerror(errno));
2308 /* Allocate a channel number for the socket. */
2309 c = channel_new("port listener", type, sock, sock, -1,
2310 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2311 0, "port listener", 1);
2312 strlcpy(c->path, host, sizeof(c->path));
2313 c->host_port = port_to_connect;
2314 c->listening_port = listen_port;
2318 error("channel_setup_fwd_listener: cannot listen to port: %d",
2320 freeaddrinfo(aitop);
2325 channel_cancel_rport_listener(const char *host, u_short port)
2330 for (i = 0; i < channels_alloc; i++) {
2331 Channel *c = channels[i];
2333 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2334 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2335 c->listening_port == port) {
2336 debug2("%s: close channel %d", __func__, i);
2345 /* protocol local port fwd, used by ssh (and sshd in v1) */
2347 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2348 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2350 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2351 listen_host, listen_port, host_to_connect, port_to_connect,
2355 /* protocol v2 remote port fwd, used by sshd */
2357 channel_setup_remote_fwd_listener(const char *listen_address,
2358 u_short listen_port, int gateway_ports)
2360 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2361 listen_address, listen_port, NULL, 0, gateway_ports);
2365 * Initiate forwarding of connections to port "port" on remote host through
2366 * the secure channel to host:port from local side.
2370 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2371 const char *host_to_connect, u_short port_to_connect)
2373 int type, success = 0;
2375 /* Record locally that connection to this host/port is permitted. */
2376 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2377 fatal("channel_request_remote_forwarding: too many forwards");
2379 /* Send the forward request to the remote side. */
2381 const char *address_to_bind;
2382 if (listen_host == NULL)
2383 address_to_bind = "localhost";
2384 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2385 address_to_bind = "";
2387 address_to_bind = listen_host;
2389 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2390 packet_put_cstring("tcpip-forward");
2391 packet_put_char(1); /* boolean: want reply */
2392 packet_put_cstring(address_to_bind);
2393 packet_put_int(listen_port);
2395 packet_write_wait();
2396 /* Assume that server accepts the request */
2399 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2400 packet_put_int(listen_port);
2401 packet_put_cstring(host_to_connect);
2402 packet_put_int(port_to_connect);
2404 packet_write_wait();
2406 /* Wait for response from the remote side. */
2407 type = packet_read();
2409 case SSH_SMSG_SUCCESS:
2412 case SSH_SMSG_FAILURE:
2413 logit("Warning: Server denied remote port forwarding.");
2416 /* Unknown packet */
2417 packet_disconnect("Protocol error for port forward request:"
2418 "received packet type %d.", type);
2422 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2423 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2424 permitted_opens[num_permitted_opens].listen_port = listen_port;
2425 num_permitted_opens++;
2430 * Request cancellation of remote forwarding of connection host:port from
2434 channel_request_rforward_cancel(const char *host, u_short port)
2441 for (i = 0; i < num_permitted_opens; i++) {
2442 if (permitted_opens[i].host_to_connect != NULL &&
2443 permitted_opens[i].listen_port == port)
2446 if (i >= num_permitted_opens) {
2447 debug("%s: requested forward not found", __func__);
2450 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2451 packet_put_cstring("cancel-tcpip-forward");
2453 packet_put_cstring(host == NULL ? "" : host);
2454 packet_put_int(port);
2457 permitted_opens[i].listen_port = 0;
2458 permitted_opens[i].port_to_connect = 0;
2459 free(permitted_opens[i].host_to_connect);
2460 permitted_opens[i].host_to_connect = NULL;
2464 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2465 * listening for the port, and sends back a success reply (or disconnect
2466 * message if there was an error). This never returns if there was an error.
2470 channel_input_port_forward_request(int is_root, int gateway_ports)
2472 u_short port, host_port;
2475 /* Get arguments from the packet. */
2476 port = packet_get_int();
2477 hostname = packet_get_string(NULL);
2478 host_port = packet_get_int();
2482 * Check that an unprivileged user is not trying to forward a
2485 if (port < IPPORT_RESERVED && !is_root)
2487 "Requested forwarding of port %d but user is not root.",
2490 packet_disconnect("Dynamic forwarding denied.");
2493 /* Initiate forwarding */
2494 channel_setup_local_fwd_listener(NULL, port, hostname,
2495 host_port, gateway_ports);
2497 /* Free the argument string. */
2502 * Permits opening to any host/port if permitted_opens[] is empty. This is
2503 * usually called by the server, because the user could connect to any port
2504 * anyway, and the server has no way to know but to trust the client anyway.
2507 channel_permit_all_opens(void)
2509 if (num_permitted_opens == 0)
2510 all_opens_permitted = 1;
2514 channel_add_permitted_opens(char *host, int port)
2516 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2517 fatal("channel_request_remote_forwarding: too many forwards");
2518 debug("allow port forwarding to host %s port %d", host, port);
2520 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2521 permitted_opens[num_permitted_opens].port_to_connect = port;
2522 num_permitted_opens++;
2524 all_opens_permitted = 0;
2528 channel_clear_permitted_opens(void)
2532 for (i = 0; i < num_permitted_opens; i++)
2533 if (permitted_opens[i].host_to_connect != NULL)
2534 xfree(permitted_opens[i].host_to_connect);
2535 num_permitted_opens = 0;
2540 /* return socket to remote host, port */
2542 connect_to(const char *host, u_short port)
2544 struct addrinfo hints, *ai, *aitop;
2545 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2549 memset(&hints, 0, sizeof(hints));
2550 hints.ai_family = IPv4or6;
2551 hints.ai_socktype = SOCK_STREAM;
2552 snprintf(strport, sizeof strport, "%d", port);
2553 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2554 error("connect_to %.100s: unknown host (%s)", host,
2555 gai_strerror(gaierr));
2558 for (ai = aitop; ai; ai = ai->ai_next) {
2559 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2561 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2562 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2563 error("connect_to: getnameinfo failed");
2566 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2568 if (ai->ai_next == NULL)
2569 error("socket: %.100s", strerror(errno));
2571 verbose("socket: %.100s", strerror(errno));
2574 if (set_nonblock(sock) == -1)
2575 fatal("%s: set_nonblock(%d)", __func__, sock);
2576 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2577 errno != EINPROGRESS) {
2578 error("connect_to %.100s port %s: %.100s", ntop, strport,
2581 continue; /* fail -- try next */
2583 break; /* success */
2586 freeaddrinfo(aitop);
2588 error("connect_to %.100s port %d: failed.", host, port);
2597 channel_connect_by_listen_address(u_short listen_port)
2601 for (i = 0; i < num_permitted_opens; i++)
2602 if (permitted_opens[i].host_to_connect != NULL &&
2603 permitted_opens[i].listen_port == listen_port)
2605 permitted_opens[i].host_to_connect,
2606 permitted_opens[i].port_to_connect);
2607 error("WARNING: Server requests forwarding for unknown listen_port %d",
2612 /* Check if connecting to that port is permitted and connect. */
2614 channel_connect_to(const char *host, u_short port)
2618 permit = all_opens_permitted;
2620 for (i = 0; i < num_permitted_opens; i++)
2621 if (permitted_opens[i].host_to_connect != NULL &&
2622 permitted_opens[i].port_to_connect == port &&
2623 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2628 logit("Received request to connect to host %.100s port %d, "
2629 "but the request was denied.", host, port);
2632 return connect_to(host, port);
2636 channel_send_window_changes(void)
2641 for (i = 0; i < channels_alloc; i++) {
2642 if (channels[i] == NULL || !channels[i]->client_tty ||
2643 channels[i]->type != SSH_CHANNEL_OPEN)
2645 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2647 channel_request_start(i, "window-change", 0);
2648 packet_put_int(ws.ws_col);
2649 packet_put_int(ws.ws_row);
2650 packet_put_int(ws.ws_xpixel);
2651 packet_put_int(ws.ws_ypixel);
2656 /* -- X11 forwarding */
2659 * Creates an internet domain socket for listening for X11 connections.
2660 * Returns 0 and a suitable display number for the DISPLAY variable
2661 * stored in display_numberp , or -1 if an error occurs.
2664 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2665 int single_connection, u_int *display_numberp, int **chanids)
2668 int display_number, sock;
2670 struct addrinfo hints, *ai, *aitop;
2671 char strport[NI_MAXSERV];
2672 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2674 if (chanids == NULL)
2677 for (display_number = x11_display_offset;
2678 display_number < MAX_DISPLAYS;
2680 port = 6000 + display_number;
2681 memset(&hints, 0, sizeof(hints));
2682 hints.ai_family = IPv4or6;
2683 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2684 hints.ai_socktype = SOCK_STREAM;
2685 snprintf(strport, sizeof strport, "%d", port);
2686 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2687 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2690 for (ai = aitop; ai; ai = ai->ai_next) {
2691 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2693 sock = socket(ai->ai_family, ai->ai_socktype,
2696 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2697 error("socket: %.100s", strerror(errno));
2698 freeaddrinfo(aitop);
2701 debug("x11_create_display_inet: Socket family %d not supported",
2707 if (ai->ai_family == AF_INET6) {
2709 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2710 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2713 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2714 debug2("bind port %d: %.100s", port, strerror(errno));
2720 for (n = 0; n < num_socks; n++) {
2726 socks[num_socks++] = sock;
2727 #ifndef DONT_TRY_OTHER_AF
2728 if (num_socks == NUM_SOCKS)
2731 if (x11_use_localhost) {
2732 if (num_socks == NUM_SOCKS)
2739 freeaddrinfo(aitop);
2743 if (display_number >= MAX_DISPLAYS) {
2744 error("Failed to allocate internet-domain X11 display socket.");
2747 /* Start listening for connections on the socket. */
2748 for (n = 0; n < num_socks; n++) {
2750 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2751 error("listen: %.100s", strerror(errno));
2757 /* Allocate a channel for each socket. */
2758 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
2759 for (n = 0; n < num_socks; n++) {
2761 nc = channel_new("x11 listener",
2762 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2763 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2764 0, "X11 inet listener", 1);
2765 nc->single_connection = single_connection;
2766 (*chanids)[n] = nc->self;
2770 /* Return the display number for the DISPLAY environment variable. */
2771 *display_numberp = display_number;
2776 connect_local_xsocket(u_int dnr)
2779 struct sockaddr_un addr;
2781 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2783 error("socket: %.100s", strerror(errno));
2784 memset(&addr, 0, sizeof(addr));
2785 addr.sun_family = AF_UNIX;
2786 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2787 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2790 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2795 x11_connect_display(void)
2797 int display_number, sock = 0;
2798 const char *display;
2799 char buf[1024], *cp;
2800 struct addrinfo hints, *ai, *aitop;
2801 char strport[NI_MAXSERV];
2804 /* Try to open a socket for the local X server. */
2805 display = getenv("DISPLAY");
2807 error("DISPLAY not set.");
2811 * Now we decode the value of the DISPLAY variable and make a
2812 * connection to the real X server.
2816 * Check if it is a unix domain socket. Unix domain displays are in
2817 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2819 if (strncmp(display, "unix:", 5) == 0 ||
2820 display[0] == ':') {
2821 /* Connect to the unix domain socket. */
2822 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2823 error("Could not parse display number from DISPLAY: %.100s",
2827 /* Create a socket. */
2828 sock = connect_local_xsocket(display_number);
2832 /* OK, we now have a connection to the display. */
2836 * Connect to an inet socket. The DISPLAY value is supposedly
2837 * hostname:d[.s], where hostname may also be numeric IP address.
2839 strlcpy(buf, display, sizeof(buf));
2840 cp = strchr(buf, ':');
2842 error("Could not find ':' in DISPLAY: %.100s", display);
2846 /* buf now contains the host name. But first we parse the display number. */
2847 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2848 error("Could not parse display number from DISPLAY: %.100s",
2853 /* Look up the host address */
2854 memset(&hints, 0, sizeof(hints));
2855 hints.ai_family = IPv4or6;
2856 hints.ai_socktype = SOCK_STREAM;
2857 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2858 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2859 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2862 for (ai = aitop; ai; ai = ai->ai_next) {
2863 /* Create a socket. */
2864 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2866 debug2("socket: %.100s", strerror(errno));
2869 /* Connect it to the display. */
2870 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2871 debug2("connect %.100s port %d: %.100s", buf,
2872 6000 + display_number, strerror(errno));
2879 freeaddrinfo(aitop);
2881 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2890 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2891 * the remote channel number. We should do whatever we want, and respond
2892 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2896 x11_input_open(int type, u_int32_t seq, void *ctxt)
2899 int remote_id, sock = 0;
2902 debug("Received X11 open request.");
2904 remote_id = packet_get_int();
2906 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2907 remote_host = packet_get_string(NULL);
2909 remote_host = xstrdup("unknown (remote did not supply name)");
2913 /* Obtain a connection to the real X display. */
2914 sock = x11_connect_display();
2916 /* Allocate a channel for this connection. */
2917 c = channel_new("connected x11 socket",
2918 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2920 c->remote_id = remote_id;
2925 /* Send refusal to the remote host. */
2926 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2927 packet_put_int(remote_id);
2929 /* Send a confirmation to the remote host. */
2930 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2931 packet_put_int(remote_id);
2932 packet_put_int(c->self);
2937 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2939 deny_input_open(int type, u_int32_t seq, void *ctxt)
2941 int rchan = packet_get_int();
2944 case SSH_SMSG_AGENT_OPEN:
2945 error("Warning: ssh server tried agent forwarding.");
2947 case SSH_SMSG_X11_OPEN:
2948 error("Warning: ssh server tried X11 forwarding.");
2951 error("deny_input_open: type %d", type);
2954 error("Warning: this is probably a break in attempt by a malicious server.");
2955 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2956 packet_put_int(rchan);
2961 * Requests forwarding of X11 connections, generates fake authentication
2962 * data, and enables authentication spoofing.
2963 * This should be called in the client only.
2966 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
2967 const char *proto, const char *data)
2969 u_int data_len = (u_int) strlen(data) / 2;
2976 if (x11_saved_display == NULL)
2977 x11_saved_display = xstrdup(disp);
2978 else if (strcmp(disp, x11_saved_display) != 0) {
2979 error("x11_request_forwarding_with_spoofing: different "
2980 "$DISPLAY already forwarded");
2986 cp = strchr(disp, ':');
2988 cp = strchr(cp, '.');
2990 screen_number = atoi(cp + 1);
2994 if (x11_saved_proto == NULL) {
2995 /* Save protocol name. */
2996 x11_saved_proto = xstrdup(proto);
2998 * Extract real authentication data and generate fake data
2999 * of the same length.
3001 x11_saved_data = xmalloc(data_len);
3002 x11_fake_data = xmalloc(data_len);
3003 for (i = 0; i < data_len; i++) {
3004 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3005 fatal("x11_request_forwarding: bad "
3006 "authentication data: %.100s", data);
3009 x11_saved_data[i] = value;
3010 x11_fake_data[i] = rnd & 0xff;
3013 x11_saved_data_len = data_len;
3014 x11_fake_data_len = data_len;
3017 /* Convert the fake data into hex. */
3018 new_data = tohex(x11_fake_data, data_len);
3020 /* Send the request packet. */
3022 channel_request_start(client_session_id, "x11-req", 0);
3023 packet_put_char(0); /* XXX bool single connection */
3025 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3027 packet_put_cstring(proto);
3028 packet_put_cstring(new_data);
3029 packet_put_int(screen_number);
3031 packet_write_wait();
3036 /* -- agent forwarding */
3038 /* Sends a message to the server to request authentication fd forwarding. */
3041 auth_request_forwarding(void)
3043 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3045 packet_write_wait();