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 1.206 2004/06/18 11:11:54 djm Exp $");
56 #include "pathnames.h"
62 * Pointer to an array containing all allocated channels. The array is
63 * dynamically extended as needed.
65 static Channel **channels = NULL;
68 * Size of the channel array. All slots of the array must always be
69 * initialized (at least the type field); unused slots set to NULL
71 static int channels_alloc = 0;
74 * Maximum file descriptor value used in any of the channels. This is
75 * updated in channel_new.
77 static int channel_max_fd = 0;
80 /* -- tcp forwarding */
83 * Data structure for storing which hosts are permitted for forward requests.
84 * The local sides of any remote forwards are stored in this array to prevent
85 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
86 * network (which might be behind a firewall).
89 char *host_to_connect; /* Connect to 'host'. */
90 u_short port_to_connect; /* Connect to 'port'. */
91 u_short listen_port; /* Remote side should listen port number. */
94 /* List of all permitted host/port pairs to connect. */
95 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
97 /* Number of permitted host/port pairs in the array. */
98 static int num_permitted_opens = 0;
100 * If this is true, all opens are permitted. This is the case on the server
101 * on which we have to trust the client anyway, and the user could do
102 * anything after logging in anyway.
104 static int all_opens_permitted = 0;
107 /* -- X11 forwarding */
109 /* Maximum number of fake X11 displays to try. */
110 #define MAX_DISPLAYS 1000
112 /* Saved X11 authentication protocol name. */
113 static char *x11_saved_proto = NULL;
115 /* Saved X11 authentication data. This is the real data. */
116 static char *x11_saved_data = NULL;
117 static u_int x11_saved_data_len = 0;
120 * Fake X11 authentication data. This is what the server will be sending us;
121 * we should replace any occurrences of this by the real data.
123 static char *x11_fake_data = NULL;
124 static u_int x11_fake_data_len;
127 /* -- agent forwarding */
131 /* AF_UNSPEC or AF_INET or AF_INET6 */
132 static int IPv4or6 = AF_UNSPEC;
135 static void port_open_helper(Channel *c, char *rtype);
137 /* -- channel core */
140 channel_lookup(int id)
144 if (id < 0 || id >= channels_alloc) {
145 logit("channel_lookup: %d: bad id", id);
150 logit("channel_lookup: %d: bad id: channel free", id);
157 * Register filedescriptors for a channel, used when allocating a channel or
158 * when the channel consumer/producer is ready, e.g. shell exec'd
162 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
163 int extusage, int nonblock)
165 /* Update the maximum file descriptor value. */
166 channel_max_fd = MAX(channel_max_fd, rfd);
167 channel_max_fd = MAX(channel_max_fd, wfd);
168 channel_max_fd = MAX(channel_max_fd, efd);
170 /* XXX set close-on-exec -markus */
174 c->sock = (rfd == wfd) ? rfd : -1;
175 c->ctl_fd = -1; /* XXX: set elsewhere */
177 c->extended_usage = extusage;
179 /* XXX ugly hack: nonblock is only set by the server */
180 if (nonblock && isatty(c->rfd)) {
181 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
183 if (!isatty(c->wfd)) {
184 error("channel %d: wfd %d is not a tty?",
190 c->wfd_isatty = isatty(c->wfd);
192 /* enable nonblocking mode */
204 * Allocate a new channel object and set its type and socket. This will cause
205 * remote_name to be freed.
209 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
210 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
215 /* Do initial allocation if this is the first call. */
216 if (channels_alloc == 0) {
218 channels = xmalloc(channels_alloc * sizeof(Channel *));
219 for (i = 0; i < channels_alloc; i++)
222 /* Try to find a free slot where to put the new channel. */
223 for (found = -1, i = 0; i < channels_alloc; i++)
224 if (channels[i] == NULL) {
225 /* Found a free slot. */
230 /* There are no free slots. Take last+1 slot and expand the array. */
231 found = channels_alloc;
232 if (channels_alloc > 10000)
233 fatal("channel_new: internal error: channels_alloc %d "
234 "too big.", channels_alloc);
235 channels = xrealloc(channels,
236 (channels_alloc + 10) * sizeof(Channel *));
237 channels_alloc += 10;
238 debug2("channel: expanding %d", channels_alloc);
239 for (i = found; i < channels_alloc; i++)
242 /* Initialize and return new channel. */
243 c = channels[found] = xmalloc(sizeof(Channel));
244 memset(c, 0, sizeof(Channel));
245 buffer_init(&c->input);
246 buffer_init(&c->output);
247 buffer_init(&c->extended);
248 c->ostate = CHAN_OUTPUT_OPEN;
249 c->istate = CHAN_INPUT_OPEN;
251 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
255 c->local_window = window;
256 c->local_window_max = window;
257 c->local_consumed = 0;
258 c->local_maxpacket = maxpack;
260 c->remote_name = xstrdup(remote_name);
261 c->remote_window = 0;
262 c->remote_maxpacket = 0;
264 c->single_connection = 0;
265 c->detach_user = NULL;
267 c->confirm_ctx = NULL;
268 c->input_filter = NULL;
269 debug("channel %d: new [%s]", found, remote_name);
274 channel_find_maxfd(void)
279 for (i = 0; i < channels_alloc; i++) {
282 max = MAX(max, c->rfd);
283 max = MAX(max, c->wfd);
284 max = MAX(max, c->efd);
291 channel_close_fd(int *fdp)
293 int ret = 0, fd = *fdp;
298 if (fd == channel_max_fd)
299 channel_max_fd = channel_find_maxfd();
304 /* Close all channel fd/socket. */
307 channel_close_fds(Channel *c)
309 debug3("channel %d: close_fds r %d w %d e %d c %d",
310 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
312 channel_close_fd(&c->sock);
313 channel_close_fd(&c->ctl_fd);
314 channel_close_fd(&c->rfd);
315 channel_close_fd(&c->wfd);
316 channel_close_fd(&c->efd);
319 /* Free the channel and close its fd/socket. */
322 channel_free(Channel *c)
327 for (n = 0, i = 0; i < channels_alloc; i++)
330 debug("channel %d: free: %s, nchannels %d", c->self,
331 c->remote_name ? c->remote_name : "???", n);
333 s = channel_open_message();
334 debug3("channel %d: status: %s", c->self, s);
338 shutdown(c->sock, SHUT_RDWR);
340 shutdown(c->ctl_fd, SHUT_RDWR);
341 channel_close_fds(c);
342 buffer_free(&c->input);
343 buffer_free(&c->output);
344 buffer_free(&c->extended);
345 if (c->remote_name) {
346 xfree(c->remote_name);
347 c->remote_name = NULL;
349 channels[c->self] = NULL;
354 channel_free_all(void)
358 for (i = 0; i < channels_alloc; i++)
359 if (channels[i] != NULL)
360 channel_free(channels[i]);
364 * Closes the sockets/fds of all channels. This is used to close extra file
365 * descriptors after a fork.
369 channel_close_all(void)
373 for (i = 0; i < channels_alloc; i++)
374 if (channels[i] != NULL)
375 channel_close_fds(channels[i]);
379 * Stop listening to channels.
383 channel_stop_listening(void)
388 for (i = 0; i < channels_alloc; i++) {
392 case SSH_CHANNEL_AUTH_SOCKET:
393 case SSH_CHANNEL_PORT_LISTENER:
394 case SSH_CHANNEL_RPORT_LISTENER:
395 case SSH_CHANNEL_X11_LISTENER:
396 channel_close_fd(&c->sock);
405 * Returns true if no channel has too much buffered data, and false if one or
406 * more channel is overfull.
410 channel_not_very_much_buffered_data(void)
415 for (i = 0; i < channels_alloc; i++) {
417 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
420 buffer_len(&c->input) > packet_get_maxsize()) {
421 debug2("channel %d: big input buffer %d",
422 c->self, buffer_len(&c->input));
426 if (buffer_len(&c->output) > packet_get_maxsize()) {
427 debug2("channel %d: big output buffer %u > %u",
428 c->self, buffer_len(&c->output),
429 packet_get_maxsize());
437 /* Returns true if any channel is still open. */
440 channel_still_open(void)
445 for (i = 0; i < channels_alloc; i++) {
450 case SSH_CHANNEL_X11_LISTENER:
451 case SSH_CHANNEL_PORT_LISTENER:
452 case SSH_CHANNEL_RPORT_LISTENER:
453 case SSH_CHANNEL_CLOSED:
454 case SSH_CHANNEL_AUTH_SOCKET:
455 case SSH_CHANNEL_DYNAMIC:
456 case SSH_CHANNEL_CONNECTING:
457 case SSH_CHANNEL_ZOMBIE:
459 case SSH_CHANNEL_LARVAL:
461 fatal("cannot happen: SSH_CHANNEL_LARVAL");
463 case SSH_CHANNEL_OPENING:
464 case SSH_CHANNEL_OPEN:
465 case SSH_CHANNEL_X11_OPEN:
467 case SSH_CHANNEL_INPUT_DRAINING:
468 case SSH_CHANNEL_OUTPUT_DRAINING:
470 fatal("cannot happen: OUT_DRAIN");
473 fatal("channel_still_open: bad channel type %d", c->type);
480 /* Returns the id of an open channel suitable for keepaliving */
483 channel_find_open(void)
488 for (i = 0; i < channels_alloc; i++) {
490 if (c == NULL || c->remote_id < 0)
493 case SSH_CHANNEL_CLOSED:
494 case SSH_CHANNEL_DYNAMIC:
495 case SSH_CHANNEL_X11_LISTENER:
496 case SSH_CHANNEL_PORT_LISTENER:
497 case SSH_CHANNEL_RPORT_LISTENER:
498 case SSH_CHANNEL_OPENING:
499 case SSH_CHANNEL_CONNECTING:
500 case SSH_CHANNEL_ZOMBIE:
502 case SSH_CHANNEL_LARVAL:
503 case SSH_CHANNEL_AUTH_SOCKET:
504 case SSH_CHANNEL_OPEN:
505 case SSH_CHANNEL_X11_OPEN:
507 case SSH_CHANNEL_INPUT_DRAINING:
508 case SSH_CHANNEL_OUTPUT_DRAINING:
510 fatal("cannot happen: OUT_DRAIN");
513 fatal("channel_find_open: bad channel type %d", c->type);
522 * Returns a message describing the currently open forwarded connections,
523 * suitable for sending to the client. The message contains crlf pairs for
528 channel_open_message(void)
535 buffer_init(&buffer);
536 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
537 buffer_append(&buffer, buf, strlen(buf));
538 for (i = 0; i < channels_alloc; i++) {
543 case SSH_CHANNEL_X11_LISTENER:
544 case SSH_CHANNEL_PORT_LISTENER:
545 case SSH_CHANNEL_RPORT_LISTENER:
546 case SSH_CHANNEL_CLOSED:
547 case SSH_CHANNEL_AUTH_SOCKET:
548 case SSH_CHANNEL_ZOMBIE:
550 case SSH_CHANNEL_LARVAL:
551 case SSH_CHANNEL_OPENING:
552 case SSH_CHANNEL_CONNECTING:
553 case SSH_CHANNEL_DYNAMIC:
554 case SSH_CHANNEL_OPEN:
555 case SSH_CHANNEL_X11_OPEN:
556 case SSH_CHANNEL_INPUT_DRAINING:
557 case SSH_CHANNEL_OUTPUT_DRAINING:
558 snprintf(buf, sizeof buf,
559 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
560 c->self, c->remote_name,
561 c->type, c->remote_id,
562 c->istate, buffer_len(&c->input),
563 c->ostate, buffer_len(&c->output),
564 c->rfd, c->wfd, c->ctl_fd);
565 buffer_append(&buffer, buf, strlen(buf));
568 fatal("channel_open_message: bad channel type %d", c->type);
572 buffer_append(&buffer, "\0", 1);
573 cp = xstrdup(buffer_ptr(&buffer));
574 buffer_free(&buffer);
579 channel_send_open(int id)
581 Channel *c = channel_lookup(id);
584 logit("channel_send_open: %d: bad id", id);
587 debug2("channel %d: send open", id);
588 packet_start(SSH2_MSG_CHANNEL_OPEN);
589 packet_put_cstring(c->ctype);
590 packet_put_int(c->self);
591 packet_put_int(c->local_window);
592 packet_put_int(c->local_maxpacket);
597 channel_request_start(int id, char *service, int wantconfirm)
599 Channel *c = channel_lookup(id);
602 logit("channel_request_start: %d: unknown channel id", id);
605 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
606 packet_start(SSH2_MSG_CHANNEL_REQUEST);
607 packet_put_int(c->remote_id);
608 packet_put_cstring(service);
609 packet_put_char(wantconfirm);
612 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
614 Channel *c = channel_lookup(id);
617 logit("channel_register_comfirm: %d: bad id", id);
621 c->confirm_ctx = ctx;
624 channel_register_cleanup(int id, channel_callback_fn *fn)
626 Channel *c = channel_lookup(id);
629 logit("channel_register_cleanup: %d: bad id", id);
635 channel_cancel_cleanup(int id)
637 Channel *c = channel_lookup(id);
640 logit("channel_cancel_cleanup: %d: bad id", id);
643 c->detach_user = NULL;
646 channel_register_filter(int id, channel_filter_fn *fn)
648 Channel *c = channel_lookup(id);
651 logit("channel_register_filter: %d: bad id", id);
654 c->input_filter = fn;
658 channel_set_fds(int id, int rfd, int wfd, int efd,
659 int extusage, int nonblock, u_int window_max)
661 Channel *c = channel_lookup(id);
663 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
664 fatal("channel_activate for non-larval channel %d.", id);
665 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
666 c->type = SSH_CHANNEL_OPEN;
667 c->local_window = c->local_window_max = window_max;
668 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
669 packet_put_int(c->remote_id);
670 packet_put_int(c->local_window);
675 * 'channel_pre*' are called just before select() to add any bits relevant to
676 * channels in the select bitmasks.
679 * 'channel_post*': perform any appropriate operations for channels which
680 * have events pending.
682 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
683 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
684 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
687 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
689 FD_SET(c->sock, readset);
693 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
695 debug3("channel %d: waiting for connection", c->self);
696 FD_SET(c->sock, writeset);
700 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
702 if (buffer_len(&c->input) < packet_get_maxsize())
703 FD_SET(c->sock, readset);
704 if (buffer_len(&c->output) > 0)
705 FD_SET(c->sock, writeset);
709 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
711 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
713 if (c->istate == CHAN_INPUT_OPEN &&
715 buffer_len(&c->input) < limit)
716 FD_SET(c->rfd, readset);
717 if (c->ostate == CHAN_OUTPUT_OPEN ||
718 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
719 if (buffer_len(&c->output) > 0) {
720 FD_SET(c->wfd, writeset);
721 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
722 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
723 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
724 c->self, c->efd, buffer_len(&c->extended));
729 /** XXX check close conditions, too */
730 if (compat20 && c->efd != -1) {
731 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
732 buffer_len(&c->extended) > 0)
733 FD_SET(c->efd, writeset);
734 else if (!(c->flags & CHAN_EOF_SENT) &&
735 c->extended_usage == CHAN_EXTENDED_READ &&
736 buffer_len(&c->extended) < c->remote_window)
737 FD_SET(c->efd, readset);
739 /* XXX: What about efd? races? */
740 if (compat20 && c->ctl_fd != -1 &&
741 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
742 FD_SET(c->ctl_fd, readset);
746 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
748 if (buffer_len(&c->input) == 0) {
749 packet_start(SSH_MSG_CHANNEL_CLOSE);
750 packet_put_int(c->remote_id);
752 c->type = SSH_CHANNEL_CLOSED;
753 debug2("channel %d: closing after input drain.", c->self);
758 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
760 if (buffer_len(&c->output) == 0)
763 FD_SET(c->sock, writeset);
767 * This is a special state for X11 authentication spoofing. An opened X11
768 * connection (when authentication spoofing is being done) remains in this
769 * state until the first packet has been completely read. The authentication
770 * data in that packet is then substituted by the real data if it matches the
771 * fake data, and the channel is put into normal mode.
772 * XXX All this happens at the client side.
773 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
776 x11_open_helper(Buffer *b)
779 u_int proto_len, data_len;
781 /* Check if the fixed size part of the packet is in buffer. */
782 if (buffer_len(b) < 12)
785 /* Parse the lengths of variable-length fields. */
787 if (ucp[0] == 0x42) { /* Byte order MSB first. */
788 proto_len = 256 * ucp[6] + ucp[7];
789 data_len = 256 * ucp[8] + ucp[9];
790 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
791 proto_len = ucp[6] + 256 * ucp[7];
792 data_len = ucp[8] + 256 * ucp[9];
794 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
799 /* Check if the whole packet is in buffer. */
801 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
804 /* Check if authentication protocol matches. */
805 if (proto_len != strlen(x11_saved_proto) ||
806 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
807 debug2("X11 connection uses different authentication protocol.");
810 /* Check if authentication data matches our fake data. */
811 if (data_len != x11_fake_data_len ||
812 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
813 x11_fake_data, x11_fake_data_len) != 0) {
814 debug2("X11 auth data does not match fake data.");
817 /* Check fake data length */
818 if (x11_fake_data_len != x11_saved_data_len) {
819 error("X11 fake_data_len %d != saved_data_len %d",
820 x11_fake_data_len, x11_saved_data_len);
824 * Received authentication protocol and data match
825 * our fake data. Substitute the fake data with real
828 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
829 x11_saved_data, x11_saved_data_len);
834 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
836 int ret = x11_open_helper(&c->output);
839 /* Start normal processing for the channel. */
840 c->type = SSH_CHANNEL_OPEN;
841 channel_pre_open_13(c, readset, writeset);
842 } else if (ret == -1) {
844 * We have received an X11 connection that has bad
845 * authentication information.
847 logit("X11 connection rejected because of wrong authentication.");
848 buffer_clear(&c->input);
849 buffer_clear(&c->output);
850 channel_close_fd(&c->sock);
852 c->type = SSH_CHANNEL_CLOSED;
853 packet_start(SSH_MSG_CHANNEL_CLOSE);
854 packet_put_int(c->remote_id);
860 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
862 int ret = x11_open_helper(&c->output);
864 /* c->force_drain = 1; */
867 c->type = SSH_CHANNEL_OPEN;
868 channel_pre_open(c, readset, writeset);
869 } else if (ret == -1) {
870 logit("X11 connection rejected because of wrong authentication.");
871 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
873 buffer_clear(&c->input);
875 buffer_clear(&c->output);
876 /* for proto v1, the peer will send an IEOF */
878 chan_write_failed(c);
880 c->type = SSH_CHANNEL_OPEN;
881 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
885 /* try to decode a socks4 header */
887 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
890 int len, have, i, found;
896 struct in_addr dest_addr;
899 debug2("channel %d: decode socks4", c->self);
901 have = buffer_len(&c->input);
902 len = sizeof(s4_req);
905 p = buffer_ptr(&c->input);
906 for (found = 0, i = len; i < have; i++) {
912 /* the peer is probably sending garbage */
913 debug("channel %d: decode socks4: too long",
920 buffer_get(&c->input, (char *)&s4_req.version, 1);
921 buffer_get(&c->input, (char *)&s4_req.command, 1);
922 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
923 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
924 have = buffer_len(&c->input);
925 p = buffer_ptr(&c->input);
927 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
929 fatal("channel %d: decode socks4: len %d > have %d",
931 strlcpy(username, p, sizeof(username));
932 buffer_consume(&c->input, len);
933 buffer_consume(&c->input, 1); /* trailing '\0' */
935 host = inet_ntoa(s4_req.dest_addr);
936 strlcpy(c->path, host, sizeof(c->path));
937 c->host_port = ntohs(s4_req.dest_port);
939 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
940 c->self, host, c->host_port, s4_req.command);
942 if (s4_req.command != 1) {
943 debug("channel %d: cannot handle: socks4 cn %d",
944 c->self, s4_req.command);
947 s4_rsp.version = 0; /* vn: 0 for reply */
948 s4_rsp.command = 90; /* cd: req granted */
949 s4_rsp.dest_port = 0; /* ignored */
950 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
951 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
955 /* try to decode a socks5 header */
956 #define SSH_SOCKS5_AUTHDONE 0x1000
957 #define SSH_SOCKS5_NOAUTH 0x00
958 #define SSH_SOCKS5_IPV4 0x01
959 #define SSH_SOCKS5_DOMAIN 0x03
960 #define SSH_SOCKS5_IPV6 0x04
961 #define SSH_SOCKS5_CONNECT 0x01
962 #define SSH_SOCKS5_SUCCESS 0x00
965 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
974 u_char *p, dest_addr[255+1];
975 int i, have, found, nmethods, addrlen, af;
977 debug2("channel %d: decode socks5", c->self);
978 p = buffer_ptr(&c->input);
981 have = buffer_len(&c->input);
982 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
983 /* format: ver | nmethods | methods */
987 if (have < nmethods + 2)
989 /* look for method: "NO AUTHENTICATION REQUIRED" */
990 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
991 if (p[i] == SSH_SOCKS5_NOAUTH ) {
997 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1001 buffer_consume(&c->input, nmethods + 2);
1002 buffer_put_char(&c->output, 0x05); /* version */
1003 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1004 FD_SET(c->sock, writeset);
1005 c->flags |= SSH_SOCKS5_AUTHDONE;
1006 debug2("channel %d: socks5 auth done", c->self);
1007 return 0; /* need more */
1009 debug2("channel %d: socks5 post auth", c->self);
1010 if (have < sizeof(s5_req)+1)
1011 return 0; /* need more */
1012 memcpy((char *)&s5_req, p, sizeof(s5_req));
1013 if (s5_req.version != 0x05 ||
1014 s5_req.command != SSH_SOCKS5_CONNECT ||
1015 s5_req.reserved != 0x00) {
1016 debug2("channel %d: only socks5 connect supported", c->self);
1019 switch(s5_req.atyp){
1020 case SSH_SOCKS5_IPV4:
1024 case SSH_SOCKS5_DOMAIN:
1025 addrlen = p[sizeof(s5_req)];
1028 case SSH_SOCKS5_IPV6:
1033 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1036 if (have < 4 + addrlen + 2)
1038 buffer_consume(&c->input, sizeof(s5_req));
1039 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1040 buffer_consume(&c->input, 1); /* host string length */
1041 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1042 buffer_get(&c->input, (char *)&dest_port, 2);
1043 dest_addr[addrlen] = '\0';
1044 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1045 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1046 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1048 c->host_port = ntohs(dest_port);
1050 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1051 c->self, c->path, c->host_port, s5_req.command);
1053 s5_rsp.version = 0x05;
1054 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1055 s5_rsp.reserved = 0; /* ignored */
1056 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1057 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1058 dest_port = 0; /* ignored */
1060 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1061 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1062 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1066 /* dynamic port forwarding */
1068 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1073 have = buffer_len(&c->input);
1075 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1076 /* buffer_dump(&c->input); */
1077 /* check if the fixed size part of the packet is in buffer. */
1080 FD_SET(c->sock, readset);
1083 /* try to guess the protocol */
1084 p = buffer_ptr(&c->input);
1087 ret = channel_decode_socks4(c, readset, writeset);
1090 ret = channel_decode_socks5(c, readset, writeset);
1098 } else if (ret == 0) {
1099 debug2("channel %d: pre_dynamic: need more", c->self);
1101 FD_SET(c->sock, readset);
1103 /* switch to the next state */
1104 c->type = SSH_CHANNEL_OPENING;
1105 port_open_helper(c, "direct-tcpip");
1109 /* This is our fake X11 server socket. */
1111 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1114 struct sockaddr addr;
1117 char buf[16384], *remote_ipaddr;
1120 if (FD_ISSET(c->sock, readset)) {
1121 debug("X11 connection requested.");
1122 addrlen = sizeof(addr);
1123 newsock = accept(c->sock, &addr, &addrlen);
1124 if (c->single_connection) {
1125 debug2("single_connection: closing X11 listener.");
1126 channel_close_fd(&c->sock);
1130 error("accept: %.100s", strerror(errno));
1133 set_nodelay(newsock);
1134 remote_ipaddr = get_peer_ipaddr(newsock);
1135 remote_port = get_peer_port(newsock);
1136 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1137 remote_ipaddr, remote_port);
1139 nc = channel_new("accepted x11 socket",
1140 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1141 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1143 packet_start(SSH2_MSG_CHANNEL_OPEN);
1144 packet_put_cstring("x11");
1145 packet_put_int(nc->self);
1146 packet_put_int(nc->local_window_max);
1147 packet_put_int(nc->local_maxpacket);
1148 /* originator ipaddr and port */
1149 packet_put_cstring(remote_ipaddr);
1150 if (datafellows & SSH_BUG_X11FWD) {
1151 debug2("ssh2 x11 bug compat mode");
1153 packet_put_int(remote_port);
1157 packet_start(SSH_SMSG_X11_OPEN);
1158 packet_put_int(nc->self);
1159 if (packet_get_protocol_flags() &
1160 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1161 packet_put_cstring(buf);
1164 xfree(remote_ipaddr);
1169 port_open_helper(Channel *c, char *rtype)
1173 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1174 u_short remote_port = get_peer_port(c->sock);
1176 direct = (strcmp(rtype, "direct-tcpip") == 0);
1178 snprintf(buf, sizeof buf,
1179 "%s: listening port %d for %.100s port %d, "
1180 "connect from %.200s port %d",
1181 rtype, c->listening_port, c->path, c->host_port,
1182 remote_ipaddr, remote_port);
1184 xfree(c->remote_name);
1185 c->remote_name = xstrdup(buf);
1188 packet_start(SSH2_MSG_CHANNEL_OPEN);
1189 packet_put_cstring(rtype);
1190 packet_put_int(c->self);
1191 packet_put_int(c->local_window_max);
1192 packet_put_int(c->local_maxpacket);
1194 /* target host, port */
1195 packet_put_cstring(c->path);
1196 packet_put_int(c->host_port);
1198 /* listen address, port */
1199 packet_put_cstring(c->path);
1200 packet_put_int(c->listening_port);
1202 /* originator host and port */
1203 packet_put_cstring(remote_ipaddr);
1204 packet_put_int(remote_port);
1207 packet_start(SSH_MSG_PORT_OPEN);
1208 packet_put_int(c->self);
1209 packet_put_cstring(c->path);
1210 packet_put_int(c->host_port);
1211 if (packet_get_protocol_flags() &
1212 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1213 packet_put_cstring(c->remote_name);
1216 xfree(remote_ipaddr);
1220 * This socket is listening for connections to a forwarded TCP/IP port.
1223 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1226 struct sockaddr addr;
1227 int newsock, nextstate;
1231 if (FD_ISSET(c->sock, readset)) {
1232 debug("Connection to port %d forwarding "
1233 "to %.100s port %d requested.",
1234 c->listening_port, c->path, c->host_port);
1236 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1237 nextstate = SSH_CHANNEL_OPENING;
1238 rtype = "forwarded-tcpip";
1240 if (c->host_port == 0) {
1241 nextstate = SSH_CHANNEL_DYNAMIC;
1242 rtype = "dynamic-tcpip";
1244 nextstate = SSH_CHANNEL_OPENING;
1245 rtype = "direct-tcpip";
1249 addrlen = sizeof(addr);
1250 newsock = accept(c->sock, &addr, &addrlen);
1252 error("accept: %.100s", strerror(errno));
1255 set_nodelay(newsock);
1256 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1257 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1258 nc->listening_port = c->listening_port;
1259 nc->host_port = c->host_port;
1260 strlcpy(nc->path, c->path, sizeof(nc->path));
1262 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1264 * do not call the channel_post handler until
1265 * this flag has been reset by a pre-handler.
1266 * otherwise the FD_ISSET calls might overflow
1270 port_open_helper(nc, rtype);
1276 * This is the authentication agent socket listening for connections from
1280 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1284 struct sockaddr addr;
1287 if (FD_ISSET(c->sock, readset)) {
1288 addrlen = sizeof(addr);
1289 newsock = accept(c->sock, &addr, &addrlen);
1291 error("accept from auth socket: %.100s", strerror(errno));
1294 nc = channel_new("accepted auth socket",
1295 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1296 c->local_window_max, c->local_maxpacket,
1297 0, "accepted auth socket", 1);
1299 packet_start(SSH2_MSG_CHANNEL_OPEN);
1300 packet_put_cstring("auth-agent@openssh.com");
1301 packet_put_int(nc->self);
1302 packet_put_int(c->local_window_max);
1303 packet_put_int(c->local_maxpacket);
1305 packet_start(SSH_SMSG_AGENT_OPEN);
1306 packet_put_int(nc->self);
1313 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1316 socklen_t sz = sizeof(err);
1318 if (FD_ISSET(c->sock, writeset)) {
1319 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1321 error("getsockopt SO_ERROR failed");
1324 debug("channel %d: connected", c->self);
1325 c->type = SSH_CHANNEL_OPEN;
1327 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1328 packet_put_int(c->remote_id);
1329 packet_put_int(c->self);
1330 packet_put_int(c->local_window);
1331 packet_put_int(c->local_maxpacket);
1333 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1334 packet_put_int(c->remote_id);
1335 packet_put_int(c->self);
1338 debug("channel %d: not connected: %s",
1339 c->self, strerror(err));
1341 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1342 packet_put_int(c->remote_id);
1343 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1344 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1345 packet_put_cstring(strerror(err));
1346 packet_put_cstring("");
1349 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1350 packet_put_int(c->remote_id);
1359 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1365 FD_ISSET(c->rfd, readset)) {
1366 len = read(c->rfd, buf, sizeof(buf));
1367 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1370 debug2("channel %d: read<=0 rfd %d len %d",
1371 c->self, c->rfd, len);
1372 if (c->type != SSH_CHANNEL_OPEN) {
1373 debug2("channel %d: not open", c->self);
1376 } else if (compat13) {
1377 buffer_clear(&c->output);
1378 c->type = SSH_CHANNEL_INPUT_DRAINING;
1379 debug2("channel %d: input draining.", c->self);
1381 chan_read_failed(c);
1385 if (c->input_filter != NULL) {
1386 if (c->input_filter(c, buf, len) == -1) {
1387 debug2("channel %d: filter stops", c->self);
1388 chan_read_failed(c);
1391 buffer_append(&c->input, buf, len);
1397 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1404 /* Send buffered output data to the socket. */
1406 FD_ISSET(c->wfd, writeset) &&
1407 buffer_len(&c->output) > 0) {
1408 data = buffer_ptr(&c->output);
1409 dlen = buffer_len(&c->output);
1411 /* XXX: Later AIX versions can't push as much data to tty */
1412 if (compat20 && c->wfd_isatty)
1413 dlen = MIN(dlen, 8*1024);
1415 len = write(c->wfd, data, dlen);
1416 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1419 if (c->type != SSH_CHANNEL_OPEN) {
1420 debug2("channel %d: not open", c->self);
1423 } else if (compat13) {
1424 buffer_clear(&c->output);
1425 debug2("channel %d: input draining.", c->self);
1426 c->type = SSH_CHANNEL_INPUT_DRAINING;
1428 chan_write_failed(c);
1432 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1433 if (tcgetattr(c->wfd, &tio) == 0 &&
1434 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1436 * Simulate echo to reduce the impact of
1437 * traffic analysis. We need to match the
1438 * size of a SSH2_MSG_CHANNEL_DATA message
1439 * (4 byte channel id + data)
1441 packet_send_ignore(4 + len);
1445 buffer_consume(&c->output, len);
1446 if (compat20 && len > 0) {
1447 c->local_consumed += len;
1453 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1458 /** XXX handle drain efd, too */
1460 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1461 FD_ISSET(c->efd, writeset) &&
1462 buffer_len(&c->extended) > 0) {
1463 len = write(c->efd, buffer_ptr(&c->extended),
1464 buffer_len(&c->extended));
1465 debug2("channel %d: written %d to efd %d",
1466 c->self, len, c->efd);
1467 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1470 debug2("channel %d: closing write-efd %d",
1472 channel_close_fd(&c->efd);
1474 buffer_consume(&c->extended, len);
1475 c->local_consumed += len;
1477 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1478 FD_ISSET(c->efd, readset)) {
1479 len = read(c->efd, buf, sizeof(buf));
1480 debug2("channel %d: read %d from efd %d",
1481 c->self, len, c->efd);
1482 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1485 debug2("channel %d: closing read-efd %d",
1487 channel_close_fd(&c->efd);
1489 buffer_append(&c->extended, buf, len);
1496 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1501 /* Monitor control fd to detect if the slave client exits */
1502 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1503 len = read(c->ctl_fd, buf, sizeof(buf));
1504 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1507 debug2("channel %d: ctl read<=0", c->self);
1508 if (c->type != SSH_CHANNEL_OPEN) {
1509 debug2("channel %d: not open", c->self);
1513 chan_read_failed(c);
1514 chan_write_failed(c);
1518 fatal("%s: unexpected data on ctl fd", __func__);
1523 channel_check_window(Channel *c)
1525 if (c->type == SSH_CHANNEL_OPEN &&
1526 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1527 c->local_window < c->local_window_max/2 &&
1528 c->local_consumed > 0) {
1529 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1530 packet_put_int(c->remote_id);
1531 packet_put_int(c->local_consumed);
1533 debug2("channel %d: window %d sent adjust %d",
1534 c->self, c->local_window,
1536 c->local_window += c->local_consumed;
1537 c->local_consumed = 0;
1543 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1547 channel_handle_rfd(c, readset, writeset);
1548 channel_handle_wfd(c, readset, writeset);
1551 channel_handle_efd(c, readset, writeset);
1552 channel_handle_ctl(c, readset, writeset);
1553 channel_check_window(c);
1557 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1561 /* Send buffered output data to the socket. */
1562 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1563 len = write(c->sock, buffer_ptr(&c->output),
1564 buffer_len(&c->output));
1566 buffer_clear(&c->output);
1568 buffer_consume(&c->output, len);
1573 channel_handler_init_20(void)
1575 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1576 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1577 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1578 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1579 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1580 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1581 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1582 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1584 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1585 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1586 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1587 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1588 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1589 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1590 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1594 channel_handler_init_13(void)
1596 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1597 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1598 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1599 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1600 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1601 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1602 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1603 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1604 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1606 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1607 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1608 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1609 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1610 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1611 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1612 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1616 channel_handler_init_15(void)
1618 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1619 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1620 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1621 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1622 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1623 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1624 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1626 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1627 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1628 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1629 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1630 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1631 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1635 channel_handler_init(void)
1639 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1640 channel_pre[i] = NULL;
1641 channel_post[i] = NULL;
1644 channel_handler_init_20();
1646 channel_handler_init_13();
1648 channel_handler_init_15();
1651 /* gc dead channels */
1653 channel_garbage_collect(Channel *c)
1657 if (c->detach_user != NULL) {
1658 if (!chan_is_dead(c, 0))
1660 debug2("channel %d: gc: notify user", c->self);
1661 c->detach_user(c->self, NULL);
1662 /* if we still have a callback */
1663 if (c->detach_user != NULL)
1665 debug2("channel %d: gc: user detached", c->self);
1667 if (!chan_is_dead(c, 1))
1669 debug2("channel %d: garbage collecting", c->self);
1674 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1676 static int did_init = 0;
1681 channel_handler_init();
1684 for (i = 0; i < channels_alloc; i++) {
1688 if (ftab[c->type] != NULL)
1689 (*ftab[c->type])(c, readset, writeset);
1690 channel_garbage_collect(c);
1695 * Allocate/update select bitmasks and add any bits relevant to channels in
1699 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1700 int *nallocp, int rekeying)
1705 n = MAX(*maxfdp, channel_max_fd);
1707 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1708 /* perhaps check sz < nalloc/2 and shrink? */
1709 if (*readsetp == NULL || sz > *nallocp) {
1710 *readsetp = xrealloc(*readsetp, sz);
1711 *writesetp = xrealloc(*writesetp, sz);
1715 memset(*readsetp, 0, sz);
1716 memset(*writesetp, 0, sz);
1719 channel_handler(channel_pre, *readsetp, *writesetp);
1723 * After select, perform any appropriate operations for channels which have
1727 channel_after_select(fd_set * readset, fd_set * writeset)
1729 channel_handler(channel_post, readset, writeset);
1733 /* If there is data to send to the connection, enqueue some of it now. */
1736 channel_output_poll(void)
1742 for (i = 0; i < channels_alloc; i++) {
1748 * We are only interested in channels that can have buffered
1752 if (c->type != SSH_CHANNEL_OPEN &&
1753 c->type != SSH_CHANNEL_INPUT_DRAINING)
1756 if (c->type != SSH_CHANNEL_OPEN)
1760 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1761 /* XXX is this true? */
1762 debug3("channel %d: will not send data after close", c->self);
1766 /* Get the amount of buffered data for this channel. */
1767 if ((c->istate == CHAN_INPUT_OPEN ||
1768 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1769 (len = buffer_len(&c->input)) > 0) {
1771 * Send some data for the other side over the secure
1775 if (len > c->remote_window)
1776 len = c->remote_window;
1777 if (len > c->remote_maxpacket)
1778 len = c->remote_maxpacket;
1780 if (packet_is_interactive()) {
1784 /* Keep the packets at reasonable size. */
1785 if (len > packet_get_maxsize()/2)
1786 len = packet_get_maxsize()/2;
1790 packet_start(compat20 ?
1791 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1792 packet_put_int(c->remote_id);
1793 packet_put_string(buffer_ptr(&c->input), len);
1795 buffer_consume(&c->input, len);
1796 c->remote_window -= len;
1798 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1800 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1802 * input-buffer is empty and read-socket shutdown:
1803 * tell peer, that we will not send more data: send IEOF.
1804 * hack for extended data: delay EOF if EFD still in use.
1806 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1807 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1808 c->self, c->efd, buffer_len(&c->extended));
1812 /* Send extended data, i.e. stderr */
1814 !(c->flags & CHAN_EOF_SENT) &&
1815 c->remote_window > 0 &&
1816 (len = buffer_len(&c->extended)) > 0 &&
1817 c->extended_usage == CHAN_EXTENDED_READ) {
1818 debug2("channel %d: rwin %u elen %u euse %d",
1819 c->self, c->remote_window, buffer_len(&c->extended),
1821 if (len > c->remote_window)
1822 len = c->remote_window;
1823 if (len > c->remote_maxpacket)
1824 len = c->remote_maxpacket;
1825 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1826 packet_put_int(c->remote_id);
1827 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1828 packet_put_string(buffer_ptr(&c->extended), len);
1830 buffer_consume(&c->extended, len);
1831 c->remote_window -= len;
1832 debug2("channel %d: sent ext data %d", c->self, len);
1838 /* -- protocol input */
1841 channel_input_data(int type, u_int32_t seq, void *ctxt)
1848 /* Get the channel number and verify it. */
1849 id = packet_get_int();
1850 c = channel_lookup(id);
1852 packet_disconnect("Received data for nonexistent channel %d.", id);
1854 /* Ignore any data for non-open channels (might happen on close) */
1855 if (c->type != SSH_CHANNEL_OPEN &&
1856 c->type != SSH_CHANNEL_X11_OPEN)
1860 data = packet_get_string(&data_len);
1863 * Ignore data for protocol > 1.3 if output end is no longer open.
1864 * For protocol 2 the sending side is reducing its window as it sends
1865 * data, so we must 'fake' consumption of the data in order to ensure
1866 * that window updates are sent back. Otherwise the connection might
1869 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1871 c->local_window -= data_len;
1872 c->local_consumed += data_len;
1879 if (data_len > c->local_maxpacket) {
1880 logit("channel %d: rcvd big packet %d, maxpack %d",
1881 c->self, data_len, c->local_maxpacket);
1883 if (data_len > c->local_window) {
1884 logit("channel %d: rcvd too much data %d, win %d",
1885 c->self, data_len, c->local_window);
1889 c->local_window -= data_len;
1892 buffer_append(&c->output, data, data_len);
1897 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1901 u_int data_len, tcode;
1904 /* Get the channel number and verify it. */
1905 id = packet_get_int();
1906 c = channel_lookup(id);
1909 packet_disconnect("Received extended_data for bad channel %d.", id);
1910 if (c->type != SSH_CHANNEL_OPEN) {
1911 logit("channel %d: ext data for non open", id);
1914 if (c->flags & CHAN_EOF_RCVD) {
1915 if (datafellows & SSH_BUG_EXTEOF)
1916 debug("channel %d: accepting ext data after eof", id);
1918 packet_disconnect("Received extended_data after EOF "
1919 "on channel %d.", id);
1921 tcode = packet_get_int();
1923 c->extended_usage != CHAN_EXTENDED_WRITE ||
1924 tcode != SSH2_EXTENDED_DATA_STDERR) {
1925 logit("channel %d: bad ext data", c->self);
1928 data = packet_get_string(&data_len);
1930 if (data_len > c->local_window) {
1931 logit("channel %d: rcvd too much extended_data %d, win %d",
1932 c->self, data_len, c->local_window);
1936 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1937 c->local_window -= data_len;
1938 buffer_append(&c->extended, data, data_len);
1943 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1948 id = packet_get_int();
1950 c = channel_lookup(id);
1952 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1955 /* XXX force input close */
1956 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1957 debug("channel %d: FORCE input drain", c->self);
1958 c->istate = CHAN_INPUT_WAIT_DRAIN;
1959 if (buffer_len(&c->input) == 0)
1966 channel_input_close(int type, u_int32_t seq, void *ctxt)
1971 id = packet_get_int();
1973 c = channel_lookup(id);
1975 packet_disconnect("Received close for nonexistent channel %d.", id);
1978 * Send a confirmation that we have closed the channel and no more
1979 * data is coming for it.
1981 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1982 packet_put_int(c->remote_id);
1986 * If the channel is in closed state, we have sent a close request,
1987 * and the other side will eventually respond with a confirmation.
1988 * Thus, we cannot free the channel here, because then there would be
1989 * no-one to receive the confirmation. The channel gets freed when
1990 * the confirmation arrives.
1992 if (c->type != SSH_CHANNEL_CLOSED) {
1994 * Not a closed channel - mark it as draining, which will
1995 * cause it to be freed later.
1997 buffer_clear(&c->input);
1998 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2002 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2004 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2006 int id = packet_get_int();
2007 Channel *c = channel_lookup(id);
2011 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2012 chan_rcvd_oclose(c);
2016 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2018 int id = packet_get_int();
2019 Channel *c = channel_lookup(id);
2023 packet_disconnect("Received close confirmation for "
2024 "out-of-range channel %d.", id);
2025 if (c->type != SSH_CHANNEL_CLOSED)
2026 packet_disconnect("Received close confirmation for "
2027 "non-closed channel %d (type %d).", id, c->type);
2032 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2037 id = packet_get_int();
2038 c = channel_lookup(id);
2040 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2041 packet_disconnect("Received open confirmation for "
2042 "non-opening channel %d.", id);
2043 remote_id = packet_get_int();
2044 /* Record the remote channel number and mark that the channel is now open. */
2045 c->remote_id = remote_id;
2046 c->type = SSH_CHANNEL_OPEN;
2049 c->remote_window = packet_get_int();
2050 c->remote_maxpacket = packet_get_int();
2052 debug2("callback start");
2053 c->confirm(c->self, c->confirm_ctx);
2054 debug2("callback done");
2056 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2057 c->remote_window, c->remote_maxpacket);
2063 reason2txt(int reason)
2066 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2067 return "administratively prohibited";
2068 case SSH2_OPEN_CONNECT_FAILED:
2069 return "connect failed";
2070 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2071 return "unknown channel type";
2072 case SSH2_OPEN_RESOURCE_SHORTAGE:
2073 return "resource shortage";
2075 return "unknown reason";
2079 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2082 char *msg = NULL, *lang = NULL;
2085 id = packet_get_int();
2086 c = channel_lookup(id);
2088 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2089 packet_disconnect("Received open failure for "
2090 "non-opening channel %d.", id);
2092 reason = packet_get_int();
2093 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2094 msg = packet_get_string(NULL);
2095 lang = packet_get_string(NULL);
2097 logit("channel %d: open failed: %s%s%s", id,
2098 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2105 /* Free the channel. This will also close the socket. */
2110 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2119 /* Get the channel number and verify it. */
2120 id = packet_get_int();
2121 c = channel_lookup(id);
2123 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2124 logit("Received window adjust for "
2125 "non-open channel %d.", id);
2128 adjust = packet_get_int();
2130 debug2("channel %d: rcvd adjust %u", id, adjust);
2131 c->remote_window += adjust;
2135 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2139 char *host, *originator_string;
2140 int remote_id, sock = -1;
2142 remote_id = packet_get_int();
2143 host = packet_get_string(NULL);
2144 host_port = packet_get_int();
2146 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2147 originator_string = packet_get_string(NULL);
2149 originator_string = xstrdup("unknown (remote did not supply name)");
2152 sock = channel_connect_to(host, host_port);
2154 c = channel_new("connected socket",
2155 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2156 originator_string, 1);
2157 c->remote_id = remote_id;
2159 xfree(originator_string);
2161 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2162 packet_put_int(remote_id);
2169 /* -- tcp forwarding */
2172 channel_set_af(int af)
2178 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2179 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2182 int success, sock, on = 1;
2183 struct addrinfo hints, *ai, *aitop;
2185 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2188 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2189 listen_addr : host_to_connect;
2192 error("No forward host name.");
2195 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2196 error("Forward host name too long.");
2201 * getaddrinfo returns a loopback address if the hostname is
2202 * set to NULL and hints.ai_flags is not AI_PASSIVE
2204 memset(&hints, 0, sizeof(hints));
2205 hints.ai_family = IPv4or6;
2206 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2207 hints.ai_socktype = SOCK_STREAM;
2208 snprintf(strport, sizeof strport, "%d", listen_port);
2209 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2210 packet_disconnect("getaddrinfo: fatal error");
2212 for (ai = aitop; ai; ai = ai->ai_next) {
2213 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2215 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2216 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2217 error("channel_setup_fwd_listener: getnameinfo failed");
2220 /* Create a port to listen for the host. */
2221 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2223 /* this is no error since kernel may not support ipv6 */
2224 verbose("socket: %.100s", strerror(errno));
2228 * Set socket options.
2229 * Allow local port reuse in TIME_WAIT.
2231 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on,
2233 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
2235 debug("Local forwarding listening on %s port %s.", ntop, strport);
2237 /* Bind the socket to the address. */
2238 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2239 /* address can be in use ipv6 address is already bound */
2241 error("bind: %.100s", strerror(errno));
2243 verbose("bind: %.100s", strerror(errno));
2248 /* Start listening for connections on the socket. */
2249 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2250 error("listen: %.100s", strerror(errno));
2254 /* Allocate a channel number for the socket. */
2255 c = channel_new("port listener", type, sock, sock, -1,
2256 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2257 0, "port listener", 1);
2258 strlcpy(c->path, host, sizeof(c->path));
2259 c->host_port = port_to_connect;
2260 c->listening_port = listen_port;
2264 error("channel_setup_fwd_listener: cannot listen to port: %d",
2266 freeaddrinfo(aitop);
2271 channel_cancel_rport_listener(const char *host, u_short port)
2275 for(i = 0; i < channels_alloc; i++) {
2276 Channel *c = channels[i];
2278 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2279 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2280 c->listening_port == port) {
2281 debug2("%s: close clannel %d", __func__, i);
2290 /* protocol local port fwd, used by ssh (and sshd in v1) */
2292 channel_setup_local_fwd_listener(u_short listen_port,
2293 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2295 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2296 NULL, listen_port, host_to_connect, port_to_connect, gateway_ports);
2299 /* protocol v2 remote port fwd, used by sshd */
2301 channel_setup_remote_fwd_listener(const char *listen_address,
2302 u_short listen_port, int gateway_ports)
2304 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2305 listen_address, listen_port, NULL, 0, gateway_ports);
2309 * Initiate forwarding of connections to port "port" on remote host through
2310 * the secure channel to host:port from local side.
2314 channel_request_remote_forwarding(u_short listen_port,
2315 const char *host_to_connect, u_short port_to_connect)
2317 int type, success = 0;
2319 /* Record locally that connection to this host/port is permitted. */
2320 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2321 fatal("channel_request_remote_forwarding: too many forwards");
2323 /* Send the forward request to the remote side. */
2325 const char *address_to_bind = "0.0.0.0";
2326 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2327 packet_put_cstring("tcpip-forward");
2328 packet_put_char(1); /* boolean: want reply */
2329 packet_put_cstring(address_to_bind);
2330 packet_put_int(listen_port);
2332 packet_write_wait();
2333 /* Assume that server accepts the request */
2336 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2337 packet_put_int(listen_port);
2338 packet_put_cstring(host_to_connect);
2339 packet_put_int(port_to_connect);
2341 packet_write_wait();
2343 /* Wait for response from the remote side. */
2344 type = packet_read();
2346 case SSH_SMSG_SUCCESS:
2349 case SSH_SMSG_FAILURE:
2350 logit("Warning: Server denied remote port forwarding.");
2353 /* Unknown packet */
2354 packet_disconnect("Protocol error for port forward request:"
2355 "received packet type %d.", type);
2359 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2360 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2361 permitted_opens[num_permitted_opens].listen_port = listen_port;
2362 num_permitted_opens++;
2367 * Request cancellation of remote forwarding of connection host:port from
2372 channel_request_rforward_cancel(u_short port)
2375 const char *address_to_bind = "0.0.0.0";
2380 for (i = 0; i < num_permitted_opens; i++) {
2381 if (permitted_opens[i].host_to_connect != NULL &&
2382 permitted_opens[i].listen_port == port)
2385 if (i >= num_permitted_opens) {
2386 debug("%s: requested forward not found", __func__);
2389 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2390 packet_put_cstring("cancel-tcpip-forward");
2392 packet_put_cstring(address_to_bind);
2393 packet_put_int(port);
2396 permitted_opens[i].listen_port = 0;
2397 permitted_opens[i].port_to_connect = 0;
2398 free(permitted_opens[i].host_to_connect);
2399 permitted_opens[i].host_to_connect = NULL;
2403 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2404 * listening for the port, and sends back a success reply (or disconnect
2405 * message if there was an error). This never returns if there was an error.
2409 channel_input_port_forward_request(int is_root, int gateway_ports)
2411 u_short port, host_port;
2414 /* Get arguments from the packet. */
2415 port = packet_get_int();
2416 hostname = packet_get_string(NULL);
2417 host_port = packet_get_int();
2421 * Check that an unprivileged user is not trying to forward a
2424 if (port < IPPORT_RESERVED && !is_root)
2426 "Requested forwarding of port %d but user is not root.",
2429 packet_disconnect("Dynamic forwarding denied.");
2432 /* Initiate forwarding */
2433 channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports);
2435 /* Free the argument string. */
2440 * Permits opening to any host/port if permitted_opens[] is empty. This is
2441 * usually called by the server, because the user could connect to any port
2442 * anyway, and the server has no way to know but to trust the client anyway.
2445 channel_permit_all_opens(void)
2447 if (num_permitted_opens == 0)
2448 all_opens_permitted = 1;
2452 channel_add_permitted_opens(char *host, int port)
2454 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2455 fatal("channel_request_remote_forwarding: too many forwards");
2456 debug("allow port forwarding to host %s port %d", host, port);
2458 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2459 permitted_opens[num_permitted_opens].port_to_connect = port;
2460 num_permitted_opens++;
2462 all_opens_permitted = 0;
2466 channel_clear_permitted_opens(void)
2470 for (i = 0; i < num_permitted_opens; i++)
2471 if (permitted_opens[i].host_to_connect != NULL)
2472 xfree(permitted_opens[i].host_to_connect);
2473 num_permitted_opens = 0;
2478 /* return socket to remote host, port */
2480 connect_to(const char *host, u_short port)
2482 struct addrinfo hints, *ai, *aitop;
2483 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2487 memset(&hints, 0, sizeof(hints));
2488 hints.ai_family = IPv4or6;
2489 hints.ai_socktype = SOCK_STREAM;
2490 snprintf(strport, sizeof strport, "%d", port);
2491 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2492 error("connect_to %.100s: unknown host (%s)", host,
2493 gai_strerror(gaierr));
2496 for (ai = aitop; ai; ai = ai->ai_next) {
2497 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2499 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2500 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2501 error("connect_to: getnameinfo failed");
2504 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2506 if (ai->ai_next == NULL)
2507 error("socket: %.100s", strerror(errno));
2509 verbose("socket: %.100s", strerror(errno));
2512 if (set_nonblock(sock) == -1)
2513 fatal("%s: set_nonblock(%d)", __func__, sock);
2514 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2515 errno != EINPROGRESS) {
2516 error("connect_to %.100s port %s: %.100s", ntop, strport,
2519 continue; /* fail -- try next */
2521 break; /* success */
2524 freeaddrinfo(aitop);
2526 error("connect_to %.100s port %d: failed.", host, port);
2535 channel_connect_by_listen_address(u_short listen_port)
2539 for (i = 0; i < num_permitted_opens; i++)
2540 if (permitted_opens[i].host_to_connect != NULL &&
2541 permitted_opens[i].listen_port == listen_port)
2543 permitted_opens[i].host_to_connect,
2544 permitted_opens[i].port_to_connect);
2545 error("WARNING: Server requests forwarding for unknown listen_port %d",
2550 /* Check if connecting to that port is permitted and connect. */
2552 channel_connect_to(const char *host, u_short port)
2556 permit = all_opens_permitted;
2558 for (i = 0; i < num_permitted_opens; i++)
2559 if (permitted_opens[i].host_to_connect != NULL &&
2560 permitted_opens[i].port_to_connect == port &&
2561 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2566 logit("Received request to connect to host %.100s port %d, "
2567 "but the request was denied.", host, port);
2570 return connect_to(host, port);
2574 channel_send_window_changes(void)
2579 for (i = 0; i < channels_alloc; i++) {
2580 if (channels[i] == NULL ||
2581 channels[i]->type != SSH_CHANNEL_OPEN)
2583 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2585 channel_request_start(i, "window-change", 0);
2586 packet_put_int(ws.ws_col);
2587 packet_put_int(ws.ws_row);
2588 packet_put_int(ws.ws_xpixel);
2589 packet_put_int(ws.ws_ypixel);
2594 /* -- X11 forwarding */
2597 * Creates an internet domain socket for listening for X11 connections.
2598 * Returns 0 and a suitable display number for the DISPLAY variable
2599 * stored in display_numberp , or -1 if an error occurs.
2602 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2603 int single_connection, u_int *display_numberp)
2606 int display_number, sock;
2608 struct addrinfo hints, *ai, *aitop;
2609 char strport[NI_MAXSERV];
2610 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2612 for (display_number = x11_display_offset;
2613 display_number < MAX_DISPLAYS;
2615 port = 6000 + display_number;
2616 memset(&hints, 0, sizeof(hints));
2617 hints.ai_family = IPv4or6;
2618 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2619 hints.ai_socktype = SOCK_STREAM;
2620 snprintf(strport, sizeof strport, "%d", port);
2621 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2622 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2625 for (ai = aitop; ai; ai = ai->ai_next) {
2626 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2628 sock = socket(ai->ai_family, ai->ai_socktype,
2631 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2632 error("socket: %.100s", strerror(errno));
2633 freeaddrinfo(aitop);
2636 debug("x11_create_display_inet: Socket family %d not supported",
2642 if (ai->ai_family == AF_INET6) {
2644 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2645 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2648 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2649 debug2("bind port %d: %.100s", port, strerror(errno));
2655 for (n = 0; n < num_socks; n++) {
2661 socks[num_socks++] = sock;
2662 #ifndef DONT_TRY_OTHER_AF
2663 if (num_socks == NUM_SOCKS)
2666 if (x11_use_localhost) {
2667 if (num_socks == NUM_SOCKS)
2674 freeaddrinfo(aitop);
2678 if (display_number >= MAX_DISPLAYS) {
2679 error("Failed to allocate internet-domain X11 display socket.");
2682 /* Start listening for connections on the socket. */
2683 for (n = 0; n < num_socks; n++) {
2685 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2686 error("listen: %.100s", strerror(errno));
2692 /* Allocate a channel for each socket. */
2693 for (n = 0; n < num_socks; n++) {
2695 nc = channel_new("x11 listener",
2696 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2697 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2698 0, "X11 inet listener", 1);
2699 nc->single_connection = single_connection;
2702 /* Return the display number for the DISPLAY environment variable. */
2703 *display_numberp = display_number;
2708 connect_local_xsocket(u_int dnr)
2711 struct sockaddr_un addr;
2713 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2715 error("socket: %.100s", strerror(errno));
2716 memset(&addr, 0, sizeof(addr));
2717 addr.sun_family = AF_UNIX;
2718 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2719 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2722 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2727 x11_connect_display(void)
2729 int display_number, sock = 0;
2730 const char *display;
2731 char buf[1024], *cp;
2732 struct addrinfo hints, *ai, *aitop;
2733 char strport[NI_MAXSERV];
2736 /* Try to open a socket for the local X server. */
2737 display = getenv("DISPLAY");
2739 error("DISPLAY not set.");
2743 * Now we decode the value of the DISPLAY variable and make a
2744 * connection to the real X server.
2748 * Check if it is a unix domain socket. Unix domain displays are in
2749 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2751 if (strncmp(display, "unix:", 5) == 0 ||
2752 display[0] == ':') {
2753 /* Connect to the unix domain socket. */
2754 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2755 error("Could not parse display number from DISPLAY: %.100s",
2759 /* Create a socket. */
2760 sock = connect_local_xsocket(display_number);
2764 /* OK, we now have a connection to the display. */
2768 * Connect to an inet socket. The DISPLAY value is supposedly
2769 * hostname:d[.s], where hostname may also be numeric IP address.
2771 strlcpy(buf, display, sizeof(buf));
2772 cp = strchr(buf, ':');
2774 error("Could not find ':' in DISPLAY: %.100s", display);
2778 /* buf now contains the host name. But first we parse the display number. */
2779 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2780 error("Could not parse display number from DISPLAY: %.100s",
2785 /* Look up the host address */
2786 memset(&hints, 0, sizeof(hints));
2787 hints.ai_family = IPv4or6;
2788 hints.ai_socktype = SOCK_STREAM;
2789 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2790 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2791 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2794 for (ai = aitop; ai; ai = ai->ai_next) {
2795 /* Create a socket. */
2796 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2798 debug2("socket: %.100s", strerror(errno));
2801 /* Connect it to the display. */
2802 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2803 debug2("connect %.100s port %d: %.100s", buf,
2804 6000 + display_number, strerror(errno));
2811 freeaddrinfo(aitop);
2813 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2822 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2823 * the remote channel number. We should do whatever we want, and respond
2824 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2828 x11_input_open(int type, u_int32_t seq, void *ctxt)
2831 int remote_id, sock = 0;
2834 debug("Received X11 open request.");
2836 remote_id = packet_get_int();
2838 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2839 remote_host = packet_get_string(NULL);
2841 remote_host = xstrdup("unknown (remote did not supply name)");
2845 /* Obtain a connection to the real X display. */
2846 sock = x11_connect_display();
2848 /* Allocate a channel for this connection. */
2849 c = channel_new("connected x11 socket",
2850 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2852 c->remote_id = remote_id;
2857 /* Send refusal to the remote host. */
2858 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2859 packet_put_int(remote_id);
2861 /* Send a confirmation to the remote host. */
2862 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2863 packet_put_int(remote_id);
2864 packet_put_int(c->self);
2869 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2871 deny_input_open(int type, u_int32_t seq, void *ctxt)
2873 int rchan = packet_get_int();
2876 case SSH_SMSG_AGENT_OPEN:
2877 error("Warning: ssh server tried agent forwarding.");
2879 case SSH_SMSG_X11_OPEN:
2880 error("Warning: ssh server tried X11 forwarding.");
2883 error("deny_input_open: type %d", type);
2886 error("Warning: this is probably a break in attempt by a malicious server.");
2887 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2888 packet_put_int(rchan);
2893 * Requests forwarding of X11 connections, generates fake authentication
2894 * data, and enables authentication spoofing.
2895 * This should be called in the client only.
2898 x11_request_forwarding_with_spoofing(int client_session_id,
2899 const char *proto, const char *data)
2901 u_int data_len = (u_int) strlen(data) / 2;
2902 u_int i, value, len;
2908 cp = getenv("DISPLAY");
2910 cp = strchr(cp, ':');
2912 cp = strchr(cp, '.');
2914 screen_number = atoi(cp + 1);
2918 /* Save protocol name. */
2919 x11_saved_proto = xstrdup(proto);
2922 * Extract real authentication data and generate fake data of the
2925 x11_saved_data = xmalloc(data_len);
2926 x11_fake_data = xmalloc(data_len);
2927 for (i = 0; i < data_len; i++) {
2928 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2929 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2931 rand = arc4random();
2932 x11_saved_data[i] = value;
2933 x11_fake_data[i] = rand & 0xff;
2936 x11_saved_data_len = data_len;
2937 x11_fake_data_len = data_len;
2939 /* Convert the fake data into hex. */
2940 len = 2 * data_len + 1;
2941 new_data = xmalloc(len);
2942 for (i = 0; i < data_len; i++)
2943 snprintf(new_data + 2 * i, len - 2 * i,
2944 "%02x", (u_char) x11_fake_data[i]);
2946 /* Send the request packet. */
2948 channel_request_start(client_session_id, "x11-req", 0);
2949 packet_put_char(0); /* XXX bool single connection */
2951 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2953 packet_put_cstring(proto);
2954 packet_put_cstring(new_data);
2955 packet_put_int(screen_number);
2957 packet_write_wait();
2962 /* -- agent forwarding */
2964 /* Sends a message to the server to request authentication fd forwarding. */
2967 auth_request_forwarding(void)
2969 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2971 packet_write_wait();