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.
43 #include <sys/ioctl.h>
44 #include <sys/types.h>
61 #include "pathnames.h"
67 * Pointer to an array containing all allocated channels. The array is
68 * dynamically extended as needed.
70 static Channel **channels = NULL;
73 * Size of the channel array. All slots of the array must always be
74 * initialized (at least the type field); unused slots set to NULL
76 static u_int channels_alloc = 0;
79 * Maximum file descriptor value used in any of the channels. This is
80 * updated in channel_new.
82 static int channel_max_fd = 0;
85 /* -- tcp forwarding */
88 * Data structure for storing which hosts are permitted for forward requests.
89 * The local sides of any remote forwards are stored in this array to prevent
90 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
91 * network (which might be behind a firewall).
94 char *host_to_connect; /* Connect to 'host'. */
95 u_short port_to_connect; /* Connect to 'port'. */
96 u_short listen_port; /* Remote side should listen port number. */
99 /* List of all permitted host/port pairs to connect. */
100 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
102 /* Number of permitted host/port pairs in the array. */
103 static int num_permitted_opens = 0;
105 * If this is true, all opens are permitted. This is the case on the server
106 * on which we have to trust the client anyway, and the user could do
107 * anything after logging in anyway.
109 static int all_opens_permitted = 0;
112 /* -- X11 forwarding */
114 /* Maximum number of fake X11 displays to try. */
115 #define MAX_DISPLAYS 1000
117 /* Saved X11 local (client) display. */
118 static char *x11_saved_display = NULL;
120 /* Saved X11 authentication protocol name. */
121 static char *x11_saved_proto = NULL;
123 /* Saved X11 authentication data. This is the real data. */
124 static char *x11_saved_data = NULL;
125 static u_int x11_saved_data_len = 0;
128 * Fake X11 authentication data. This is what the server will be sending us;
129 * we should replace any occurrences of this by the real data.
131 static char *x11_fake_data = NULL;
132 static u_int x11_fake_data_len;
135 /* -- agent forwarding */
139 /* AF_UNSPEC or AF_INET or AF_INET6 */
140 static int IPv4or6 = AF_UNSPEC;
143 static void port_open_helper(Channel *c, char *rtype);
145 /* -- channel core */
148 channel_by_id(int id)
152 if (id < 0 || (u_int)id >= channels_alloc) {
153 logit("channel_by_id: %d: bad id", id);
158 logit("channel_by_id: %d: bad id: channel free", id);
165 * Returns the channel if it is allowed to receive protocol messages.
166 * Private channels, like listening sockets, may not receive messages.
169 channel_lookup(int id)
173 if ((c = channel_by_id(id)) == NULL)
177 case SSH_CHANNEL_X11_OPEN:
178 case SSH_CHANNEL_LARVAL:
179 case SSH_CHANNEL_CONNECTING:
180 case SSH_CHANNEL_DYNAMIC:
181 case SSH_CHANNEL_OPENING:
182 case SSH_CHANNEL_OPEN:
183 case SSH_CHANNEL_INPUT_DRAINING:
184 case SSH_CHANNEL_OUTPUT_DRAINING:
188 logit("Non-public channel %d, type %d.", id, c->type);
193 * Register filedescriptors for a channel, used when allocating a channel or
194 * when the channel consumer/producer is ready, e.g. shell exec'd
198 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
199 int extusage, int nonblock)
201 /* Update the maximum file descriptor value. */
202 channel_max_fd = MAX(channel_max_fd, rfd);
203 channel_max_fd = MAX(channel_max_fd, wfd);
204 channel_max_fd = MAX(channel_max_fd, efd);
206 /* XXX set close-on-exec -markus */
210 c->sock = (rfd == wfd) ? rfd : -1;
211 c->ctl_fd = -1; /* XXX: set elsewhere */
213 c->extended_usage = extusage;
215 /* XXX ugly hack: nonblock is only set by the server */
216 if (nonblock && isatty(c->rfd)) {
217 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
219 if (!isatty(c->wfd)) {
220 error("channel %d: wfd %d is not a tty?",
226 c->wfd_isatty = isatty(c->wfd);
228 /* enable nonblocking mode */
240 * Allocate a new channel object and set its type and socket. This will cause
241 * remote_name to be freed.
245 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
246 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
252 /* Do initial allocation if this is the first call. */
253 if (channels_alloc == 0) {
255 channels = xmalloc(channels_alloc * sizeof(Channel *));
256 for (i = 0; i < channels_alloc; i++)
259 /* Try to find a free slot where to put the new channel. */
260 for (found = -1, i = 0; i < channels_alloc; i++)
261 if (channels[i] == NULL) {
262 /* Found a free slot. */
267 /* There are no free slots. Take last+1 slot and expand the array. */
268 found = channels_alloc;
269 if (channels_alloc > 10000)
270 fatal("channel_new: internal error: channels_alloc %d "
271 "too big.", channels_alloc);
272 channels = xrealloc(channels,
273 (channels_alloc + 10) * sizeof(Channel *));
274 channels_alloc += 10;
275 debug2("channel: expanding %d", channels_alloc);
276 for (i = found; i < channels_alloc; i++)
279 /* Initialize and return new channel. */
280 c = channels[found] = xmalloc(sizeof(Channel));
281 memset(c, 0, sizeof(Channel));
282 buffer_init(&c->input);
283 buffer_init(&c->output);
284 buffer_init(&c->extended);
285 c->ostate = CHAN_OUTPUT_OPEN;
286 c->istate = CHAN_INPUT_OPEN;
288 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
292 c->local_window = window;
293 c->local_window_max = window;
294 c->local_consumed = 0;
295 c->local_maxpacket = maxpack;
297 c->remote_name = xstrdup(remote_name);
298 c->remote_window = 0;
299 c->remote_maxpacket = 0;
301 c->single_connection = 0;
302 c->detach_user = NULL;
305 c->confirm_ctx = NULL;
306 c->input_filter = NULL;
307 c->output_filter = NULL;
308 debug("channel %d: new [%s]", found, remote_name);
313 channel_find_maxfd(void)
319 for (i = 0; i < channels_alloc; i++) {
322 max = MAX(max, c->rfd);
323 max = MAX(max, c->wfd);
324 max = MAX(max, c->efd);
331 channel_close_fd(int *fdp)
333 int ret = 0, fd = *fdp;
338 if (fd == channel_max_fd)
339 channel_max_fd = channel_find_maxfd();
344 /* Close all channel fd/socket. */
347 channel_close_fds(Channel *c)
349 debug3("channel %d: close_fds r %d w %d e %d c %d",
350 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
352 channel_close_fd(&c->sock);
353 channel_close_fd(&c->ctl_fd);
354 channel_close_fd(&c->rfd);
355 channel_close_fd(&c->wfd);
356 channel_close_fd(&c->efd);
359 /* Free the channel and close its fd/socket. */
362 channel_free(Channel *c)
367 for (n = 0, i = 0; i < channels_alloc; i++)
370 debug("channel %d: free: %s, nchannels %u", c->self,
371 c->remote_name ? c->remote_name : "???", n);
373 s = channel_open_message();
374 debug3("channel %d: status: %s", c->self, s);
378 shutdown(c->sock, SHUT_RDWR);
380 shutdown(c->ctl_fd, SHUT_RDWR);
381 channel_close_fds(c);
382 buffer_free(&c->input);
383 buffer_free(&c->output);
384 buffer_free(&c->extended);
385 if (c->remote_name) {
386 xfree(c->remote_name);
387 c->remote_name = NULL;
389 channels[c->self] = NULL;
394 channel_free_all(void)
398 for (i = 0; i < channels_alloc; i++)
399 if (channels[i] != NULL)
400 channel_free(channels[i]);
404 * Closes the sockets/fds of all channels. This is used to close extra file
405 * descriptors after a fork.
409 channel_close_all(void)
413 for (i = 0; i < channels_alloc; i++)
414 if (channels[i] != NULL)
415 channel_close_fds(channels[i]);
419 * Stop listening to channels.
423 channel_stop_listening(void)
428 for (i = 0; i < channels_alloc; i++) {
432 case SSH_CHANNEL_AUTH_SOCKET:
433 case SSH_CHANNEL_PORT_LISTENER:
434 case SSH_CHANNEL_RPORT_LISTENER:
435 case SSH_CHANNEL_X11_LISTENER:
436 channel_close_fd(&c->sock);
445 * Returns true if no channel has too much buffered data, and false if one or
446 * more channel is overfull.
450 channel_not_very_much_buffered_data(void)
455 for (i = 0; i < channels_alloc; i++) {
457 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
460 buffer_len(&c->input) > packet_get_maxsize()) {
461 debug2("channel %d: big input buffer %d",
462 c->self, buffer_len(&c->input));
466 if (buffer_len(&c->output) > packet_get_maxsize()) {
467 debug2("channel %d: big output buffer %u > %u",
468 c->self, buffer_len(&c->output),
469 packet_get_maxsize());
477 /* Returns true if any channel is still open. */
480 channel_still_open(void)
485 for (i = 0; i < channels_alloc; i++) {
490 case SSH_CHANNEL_X11_LISTENER:
491 case SSH_CHANNEL_PORT_LISTENER:
492 case SSH_CHANNEL_RPORT_LISTENER:
493 case SSH_CHANNEL_CLOSED:
494 case SSH_CHANNEL_AUTH_SOCKET:
495 case SSH_CHANNEL_DYNAMIC:
496 case SSH_CHANNEL_CONNECTING:
497 case SSH_CHANNEL_ZOMBIE:
499 case SSH_CHANNEL_LARVAL:
501 fatal("cannot happen: SSH_CHANNEL_LARVAL");
503 case SSH_CHANNEL_OPENING:
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_still_open: bad channel type %d", c->type);
520 /* Returns the id of an open channel suitable for keepaliving */
523 channel_find_open(void)
528 for (i = 0; i < channels_alloc; i++) {
530 if (c == NULL || c->remote_id < 0)
533 case SSH_CHANNEL_CLOSED:
534 case SSH_CHANNEL_DYNAMIC:
535 case SSH_CHANNEL_X11_LISTENER:
536 case SSH_CHANNEL_PORT_LISTENER:
537 case SSH_CHANNEL_RPORT_LISTENER:
538 case SSH_CHANNEL_OPENING:
539 case SSH_CHANNEL_CONNECTING:
540 case SSH_CHANNEL_ZOMBIE:
542 case SSH_CHANNEL_LARVAL:
543 case SSH_CHANNEL_AUTH_SOCKET:
544 case SSH_CHANNEL_OPEN:
545 case SSH_CHANNEL_X11_OPEN:
547 case SSH_CHANNEL_INPUT_DRAINING:
548 case SSH_CHANNEL_OUTPUT_DRAINING:
550 fatal("cannot happen: OUT_DRAIN");
553 fatal("channel_find_open: bad channel type %d", c->type);
562 * Returns a message describing the currently open forwarded connections,
563 * suitable for sending to the client. The message contains crlf pairs for
568 channel_open_message(void)
575 buffer_init(&buffer);
576 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
577 buffer_append(&buffer, buf, strlen(buf));
578 for (i = 0; i < channels_alloc; i++) {
583 case SSH_CHANNEL_X11_LISTENER:
584 case SSH_CHANNEL_PORT_LISTENER:
585 case SSH_CHANNEL_RPORT_LISTENER:
586 case SSH_CHANNEL_CLOSED:
587 case SSH_CHANNEL_AUTH_SOCKET:
588 case SSH_CHANNEL_ZOMBIE:
590 case SSH_CHANNEL_LARVAL:
591 case SSH_CHANNEL_OPENING:
592 case SSH_CHANNEL_CONNECTING:
593 case SSH_CHANNEL_DYNAMIC:
594 case SSH_CHANNEL_OPEN:
595 case SSH_CHANNEL_X11_OPEN:
596 case SSH_CHANNEL_INPUT_DRAINING:
597 case SSH_CHANNEL_OUTPUT_DRAINING:
598 snprintf(buf, sizeof buf,
599 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
600 c->self, c->remote_name,
601 c->type, c->remote_id,
602 c->istate, buffer_len(&c->input),
603 c->ostate, buffer_len(&c->output),
604 c->rfd, c->wfd, c->ctl_fd);
605 buffer_append(&buffer, buf, strlen(buf));
608 fatal("channel_open_message: bad channel type %d", c->type);
612 buffer_append(&buffer, "\0", 1);
613 cp = xstrdup(buffer_ptr(&buffer));
614 buffer_free(&buffer);
619 channel_send_open(int id)
621 Channel *c = channel_lookup(id);
624 logit("channel_send_open: %d: bad id", id);
627 debug2("channel %d: send open", id);
628 packet_start(SSH2_MSG_CHANNEL_OPEN);
629 packet_put_cstring(c->ctype);
630 packet_put_int(c->self);
631 packet_put_int(c->local_window);
632 packet_put_int(c->local_maxpacket);
637 channel_request_start(int id, char *service, int wantconfirm)
639 Channel *c = channel_lookup(id);
642 logit("channel_request_start: %d: unknown channel id", id);
645 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
646 packet_start(SSH2_MSG_CHANNEL_REQUEST);
647 packet_put_int(c->remote_id);
648 packet_put_cstring(service);
649 packet_put_char(wantconfirm);
652 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
654 Channel *c = channel_lookup(id);
657 logit("channel_register_comfirm: %d: bad id", id);
661 c->confirm_ctx = ctx;
664 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
666 Channel *c = channel_by_id(id);
669 logit("channel_register_cleanup: %d: bad id", id);
673 c->detach_close = do_close;
676 channel_cancel_cleanup(int id)
678 Channel *c = channel_by_id(id);
681 logit("channel_cancel_cleanup: %d: bad id", id);
684 c->detach_user = NULL;
688 channel_register_filter(int id, channel_infilter_fn *ifn,
689 channel_outfilter_fn *ofn)
691 Channel *c = channel_lookup(id);
694 logit("channel_register_filter: %d: bad id", id);
697 c->input_filter = ifn;
698 c->output_filter = ofn;
702 channel_set_fds(int id, int rfd, int wfd, int efd,
703 int extusage, int nonblock, u_int window_max)
705 Channel *c = channel_lookup(id);
707 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
708 fatal("channel_activate for non-larval channel %d.", id);
709 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
710 c->type = SSH_CHANNEL_OPEN;
711 c->local_window = c->local_window_max = window_max;
712 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
713 packet_put_int(c->remote_id);
714 packet_put_int(c->local_window);
719 * 'channel_pre*' are called just before select() to add any bits relevant to
720 * channels in the select bitmasks.
723 * 'channel_post*': perform any appropriate operations for channels which
724 * have events pending.
726 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
727 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
728 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
731 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
733 FD_SET(c->sock, readset);
737 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
739 debug3("channel %d: waiting for connection", c->self);
740 FD_SET(c->sock, writeset);
744 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
746 if (buffer_len(&c->input) < packet_get_maxsize())
747 FD_SET(c->sock, readset);
748 if (buffer_len(&c->output) > 0)
749 FD_SET(c->sock, writeset);
753 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
755 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
757 /* check buffer limits */
758 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
760 if (c->istate == CHAN_INPUT_OPEN &&
762 buffer_len(&c->input) < limit)
763 FD_SET(c->rfd, readset);
764 if (c->ostate == CHAN_OUTPUT_OPEN ||
765 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
766 if (buffer_len(&c->output) > 0) {
767 FD_SET(c->wfd, writeset);
768 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
769 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
770 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
771 c->self, c->efd, buffer_len(&c->extended));
776 /** XXX check close conditions, too */
777 if (compat20 && c->efd != -1) {
778 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
779 buffer_len(&c->extended) > 0)
780 FD_SET(c->efd, writeset);
781 else if (!(c->flags & CHAN_EOF_SENT) &&
782 c->extended_usage == CHAN_EXTENDED_READ &&
783 buffer_len(&c->extended) < c->remote_window)
784 FD_SET(c->efd, readset);
786 /* XXX: What about efd? races? */
787 if (compat20 && c->ctl_fd != -1 &&
788 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
789 FD_SET(c->ctl_fd, readset);
793 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
795 if (buffer_len(&c->input) == 0) {
796 packet_start(SSH_MSG_CHANNEL_CLOSE);
797 packet_put_int(c->remote_id);
799 c->type = SSH_CHANNEL_CLOSED;
800 debug2("channel %d: closing after input drain.", c->self);
805 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
807 if (buffer_len(&c->output) == 0)
810 FD_SET(c->sock, writeset);
814 * This is a special state for X11 authentication spoofing. An opened X11
815 * connection (when authentication spoofing is being done) remains in this
816 * state until the first packet has been completely read. The authentication
817 * data in that packet is then substituted by the real data if it matches the
818 * fake data, and the channel is put into normal mode.
819 * XXX All this happens at the client side.
820 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
823 x11_open_helper(Buffer *b)
826 u_int proto_len, data_len;
828 /* Check if the fixed size part of the packet is in buffer. */
829 if (buffer_len(b) < 12)
832 /* Parse the lengths of variable-length fields. */
834 if (ucp[0] == 0x42) { /* Byte order MSB first. */
835 proto_len = 256 * ucp[6] + ucp[7];
836 data_len = 256 * ucp[8] + ucp[9];
837 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
838 proto_len = ucp[6] + 256 * ucp[7];
839 data_len = ucp[8] + 256 * ucp[9];
841 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
846 /* Check if the whole packet is in buffer. */
848 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
851 /* Check if authentication protocol matches. */
852 if (proto_len != strlen(x11_saved_proto) ||
853 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
854 debug2("X11 connection uses different authentication protocol.");
857 /* Check if authentication data matches our fake data. */
858 if (data_len != x11_fake_data_len ||
859 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
860 x11_fake_data, x11_fake_data_len) != 0) {
861 debug2("X11 auth data does not match fake data.");
864 /* Check fake data length */
865 if (x11_fake_data_len != x11_saved_data_len) {
866 error("X11 fake_data_len %d != saved_data_len %d",
867 x11_fake_data_len, x11_saved_data_len);
871 * Received authentication protocol and data match
872 * our fake data. Substitute the fake data with real
875 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
876 x11_saved_data, x11_saved_data_len);
881 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
883 int ret = x11_open_helper(&c->output);
886 /* Start normal processing for the channel. */
887 c->type = SSH_CHANNEL_OPEN;
888 channel_pre_open_13(c, readset, writeset);
889 } else if (ret == -1) {
891 * We have received an X11 connection that has bad
892 * authentication information.
894 logit("X11 connection rejected because of wrong authentication.");
895 buffer_clear(&c->input);
896 buffer_clear(&c->output);
897 channel_close_fd(&c->sock);
899 c->type = SSH_CHANNEL_CLOSED;
900 packet_start(SSH_MSG_CHANNEL_CLOSE);
901 packet_put_int(c->remote_id);
907 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
909 int ret = x11_open_helper(&c->output);
911 /* c->force_drain = 1; */
914 c->type = SSH_CHANNEL_OPEN;
915 channel_pre_open(c, readset, writeset);
916 } else if (ret == -1) {
917 logit("X11 connection rejected because of wrong authentication.");
918 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
920 buffer_clear(&c->input);
922 buffer_clear(&c->output);
923 /* for proto v1, the peer will send an IEOF */
925 chan_write_failed(c);
927 c->type = SSH_CHANNEL_OPEN;
928 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
932 /* try to decode a socks4 header */
934 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
937 u_int len, have, i, found;
943 struct in_addr dest_addr;
946 debug2("channel %d: decode socks4", c->self);
948 have = buffer_len(&c->input);
949 len = sizeof(s4_req);
952 p = buffer_ptr(&c->input);
953 for (found = 0, i = len; i < have; i++) {
959 /* the peer is probably sending garbage */
960 debug("channel %d: decode socks4: too long",
967 buffer_get(&c->input, (char *)&s4_req.version, 1);
968 buffer_get(&c->input, (char *)&s4_req.command, 1);
969 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
970 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
971 have = buffer_len(&c->input);
972 p = buffer_ptr(&c->input);
974 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
976 fatal("channel %d: decode socks4: len %d > have %d",
978 strlcpy(username, p, sizeof(username));
979 buffer_consume(&c->input, len);
980 buffer_consume(&c->input, 1); /* trailing '\0' */
982 host = inet_ntoa(s4_req.dest_addr);
983 strlcpy(c->path, host, sizeof(c->path));
984 c->host_port = ntohs(s4_req.dest_port);
986 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
987 c->self, host, c->host_port, s4_req.command);
989 if (s4_req.command != 1) {
990 debug("channel %d: cannot handle: socks4 cn %d",
991 c->self, s4_req.command);
994 s4_rsp.version = 0; /* vn: 0 for reply */
995 s4_rsp.command = 90; /* cd: req granted */
996 s4_rsp.dest_port = 0; /* ignored */
997 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
998 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
1002 /* try to decode a socks5 header */
1003 #define SSH_SOCKS5_AUTHDONE 0x1000
1004 #define SSH_SOCKS5_NOAUTH 0x00
1005 #define SSH_SOCKS5_IPV4 0x01
1006 #define SSH_SOCKS5_DOMAIN 0x03
1007 #define SSH_SOCKS5_IPV6 0x04
1008 #define SSH_SOCKS5_CONNECT 0x01
1009 #define SSH_SOCKS5_SUCCESS 0x00
1012 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
1020 u_int16_t dest_port;
1021 u_char *p, dest_addr[255+1];
1022 u_int have, i, found, nmethods, addrlen, af;
1024 debug2("channel %d: decode socks5", c->self);
1025 p = buffer_ptr(&c->input);
1028 have = buffer_len(&c->input);
1029 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1030 /* format: ver | nmethods | methods */
1034 if (have < nmethods + 2)
1036 /* look for method: "NO AUTHENTICATION REQUIRED" */
1037 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1038 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1044 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1048 buffer_consume(&c->input, nmethods + 2);
1049 buffer_put_char(&c->output, 0x05); /* version */
1050 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1051 FD_SET(c->sock, writeset);
1052 c->flags |= SSH_SOCKS5_AUTHDONE;
1053 debug2("channel %d: socks5 auth done", c->self);
1054 return 0; /* need more */
1056 debug2("channel %d: socks5 post auth", c->self);
1057 if (have < sizeof(s5_req)+1)
1058 return 0; /* need more */
1059 memcpy((char *)&s5_req, p, sizeof(s5_req));
1060 if (s5_req.version != 0x05 ||
1061 s5_req.command != SSH_SOCKS5_CONNECT ||
1062 s5_req.reserved != 0x00) {
1063 debug2("channel %d: only socks5 connect supported", c->self);
1066 switch (s5_req.atyp){
1067 case SSH_SOCKS5_IPV4:
1071 case SSH_SOCKS5_DOMAIN:
1072 addrlen = p[sizeof(s5_req)];
1075 case SSH_SOCKS5_IPV6:
1080 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1083 if (have < 4 + addrlen + 2)
1085 buffer_consume(&c->input, sizeof(s5_req));
1086 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1087 buffer_consume(&c->input, 1); /* host string length */
1088 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1089 buffer_get(&c->input, (char *)&dest_port, 2);
1090 dest_addr[addrlen] = '\0';
1091 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1092 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1093 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1095 c->host_port = ntohs(dest_port);
1097 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1098 c->self, c->path, c->host_port, s5_req.command);
1100 s5_rsp.version = 0x05;
1101 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1102 s5_rsp.reserved = 0; /* ignored */
1103 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1104 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1105 dest_port = 0; /* ignored */
1107 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1108 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1109 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1113 /* dynamic port forwarding */
1115 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1121 have = buffer_len(&c->input);
1123 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1124 /* buffer_dump(&c->input); */
1125 /* check if the fixed size part of the packet is in buffer. */
1128 FD_SET(c->sock, readset);
1131 /* try to guess the protocol */
1132 p = buffer_ptr(&c->input);
1135 ret = channel_decode_socks4(c, readset, writeset);
1138 ret = channel_decode_socks5(c, readset, writeset);
1146 } else if (ret == 0) {
1147 debug2("channel %d: pre_dynamic: need more", c->self);
1149 FD_SET(c->sock, readset);
1151 /* switch to the next state */
1152 c->type = SSH_CHANNEL_OPENING;
1153 port_open_helper(c, "direct-tcpip");
1157 /* This is our fake X11 server socket. */
1159 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1162 struct sockaddr addr;
1165 char buf[16384], *remote_ipaddr;
1168 if (FD_ISSET(c->sock, readset)) {
1169 debug("X11 connection requested.");
1170 addrlen = sizeof(addr);
1171 newsock = accept(c->sock, &addr, &addrlen);
1172 if (c->single_connection) {
1173 debug2("single_connection: closing X11 listener.");
1174 channel_close_fd(&c->sock);
1178 error("accept: %.100s", strerror(errno));
1181 set_nodelay(newsock);
1182 remote_ipaddr = get_peer_ipaddr(newsock);
1183 remote_port = get_peer_port(newsock);
1184 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1185 remote_ipaddr, remote_port);
1187 nc = channel_new("accepted x11 socket",
1188 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1189 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1191 packet_start(SSH2_MSG_CHANNEL_OPEN);
1192 packet_put_cstring("x11");
1193 packet_put_int(nc->self);
1194 packet_put_int(nc->local_window_max);
1195 packet_put_int(nc->local_maxpacket);
1196 /* originator ipaddr and port */
1197 packet_put_cstring(remote_ipaddr);
1198 if (datafellows & SSH_BUG_X11FWD) {
1199 debug2("ssh2 x11 bug compat mode");
1201 packet_put_int(remote_port);
1205 packet_start(SSH_SMSG_X11_OPEN);
1206 packet_put_int(nc->self);
1207 if (packet_get_protocol_flags() &
1208 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1209 packet_put_cstring(buf);
1212 xfree(remote_ipaddr);
1217 port_open_helper(Channel *c, char *rtype)
1221 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1222 int remote_port = get_peer_port(c->sock);
1224 direct = (strcmp(rtype, "direct-tcpip") == 0);
1226 snprintf(buf, sizeof buf,
1227 "%s: listening port %d for %.100s port %d, "
1228 "connect from %.200s port %d",
1229 rtype, c->listening_port, c->path, c->host_port,
1230 remote_ipaddr, remote_port);
1232 xfree(c->remote_name);
1233 c->remote_name = xstrdup(buf);
1236 packet_start(SSH2_MSG_CHANNEL_OPEN);
1237 packet_put_cstring(rtype);
1238 packet_put_int(c->self);
1239 packet_put_int(c->local_window_max);
1240 packet_put_int(c->local_maxpacket);
1242 /* target host, port */
1243 packet_put_cstring(c->path);
1244 packet_put_int(c->host_port);
1246 /* listen address, port */
1247 packet_put_cstring(c->path);
1248 packet_put_int(c->listening_port);
1250 /* originator host and port */
1251 packet_put_cstring(remote_ipaddr);
1252 packet_put_int((u_int)remote_port);
1255 packet_start(SSH_MSG_PORT_OPEN);
1256 packet_put_int(c->self);
1257 packet_put_cstring(c->path);
1258 packet_put_int(c->host_port);
1259 if (packet_get_protocol_flags() &
1260 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1261 packet_put_cstring(c->remote_name);
1264 xfree(remote_ipaddr);
1268 channel_set_reuseaddr(int fd)
1273 * Set socket options.
1274 * Allow local port reuse in TIME_WAIT.
1276 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1277 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1281 * This socket is listening for connections to a forwarded TCP/IP port.
1284 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1287 struct sockaddr addr;
1288 int newsock, nextstate;
1292 if (FD_ISSET(c->sock, readset)) {
1293 debug("Connection to port %d forwarding "
1294 "to %.100s port %d requested.",
1295 c->listening_port, c->path, c->host_port);
1297 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1298 nextstate = SSH_CHANNEL_OPENING;
1299 rtype = "forwarded-tcpip";
1301 if (c->host_port == 0) {
1302 nextstate = SSH_CHANNEL_DYNAMIC;
1303 rtype = "dynamic-tcpip";
1305 nextstate = SSH_CHANNEL_OPENING;
1306 rtype = "direct-tcpip";
1310 addrlen = sizeof(addr);
1311 newsock = accept(c->sock, &addr, &addrlen);
1313 error("accept: %.100s", strerror(errno));
1316 set_nodelay(newsock);
1317 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1318 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1319 nc->listening_port = c->listening_port;
1320 nc->host_port = c->host_port;
1321 strlcpy(nc->path, c->path, sizeof(nc->path));
1323 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1325 * do not call the channel_post handler until
1326 * this flag has been reset by a pre-handler.
1327 * otherwise the FD_ISSET calls might overflow
1331 port_open_helper(nc, rtype);
1337 * This is the authentication agent socket listening for connections from
1341 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1345 struct sockaddr addr;
1348 if (FD_ISSET(c->sock, readset)) {
1349 addrlen = sizeof(addr);
1350 newsock = accept(c->sock, &addr, &addrlen);
1352 error("accept from auth socket: %.100s", strerror(errno));
1355 nc = channel_new("accepted auth socket",
1356 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1357 c->local_window_max, c->local_maxpacket,
1358 0, "accepted auth socket", 1);
1360 packet_start(SSH2_MSG_CHANNEL_OPEN);
1361 packet_put_cstring("auth-agent@openssh.com");
1362 packet_put_int(nc->self);
1363 packet_put_int(c->local_window_max);
1364 packet_put_int(c->local_maxpacket);
1366 packet_start(SSH_SMSG_AGENT_OPEN);
1367 packet_put_int(nc->self);
1374 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1377 socklen_t sz = sizeof(err);
1379 if (FD_ISSET(c->sock, writeset)) {
1380 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1382 error("getsockopt SO_ERROR failed");
1385 debug("channel %d: connected", c->self);
1386 c->type = SSH_CHANNEL_OPEN;
1388 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1389 packet_put_int(c->remote_id);
1390 packet_put_int(c->self);
1391 packet_put_int(c->local_window);
1392 packet_put_int(c->local_maxpacket);
1394 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1395 packet_put_int(c->remote_id);
1396 packet_put_int(c->self);
1399 debug("channel %d: not connected: %s",
1400 c->self, strerror(err));
1402 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1403 packet_put_int(c->remote_id);
1404 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1405 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1406 packet_put_cstring(strerror(err));
1407 packet_put_cstring("");
1410 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1411 packet_put_int(c->remote_id);
1420 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1422 char buf[CHAN_RBUF];
1426 FD_ISSET(c->rfd, readset)) {
1427 len = read(c->rfd, buf, sizeof(buf));
1428 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1431 debug2("channel %d: read<=0 rfd %d len %d",
1432 c->self, c->rfd, len);
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 c->type = SSH_CHANNEL_INPUT_DRAINING;
1440 debug2("channel %d: input draining.", c->self);
1442 chan_read_failed(c);
1446 if (c->input_filter != NULL) {
1447 if (c->input_filter(c, buf, len) == -1) {
1448 debug2("channel %d: filter stops", c->self);
1449 chan_read_failed(c);
1451 } else if (c->datagram) {
1452 buffer_put_string(&c->input, buf, len);
1454 buffer_append(&c->input, buf, len);
1460 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1463 u_char *data = NULL, *buf;
1467 /* Send buffered output data to the socket. */
1469 FD_ISSET(c->wfd, writeset) &&
1470 buffer_len(&c->output) > 0) {
1471 if (c->output_filter != NULL) {
1472 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1473 debug2("channel %d: filter stops", c->self);
1474 if (c->type != SSH_CHANNEL_OPEN)
1477 chan_write_failed(c);
1480 } else if (c->datagram) {
1481 buf = data = buffer_get_string(&c->output, &dlen);
1483 buf = data = buffer_ptr(&c->output);
1484 dlen = buffer_len(&c->output);
1488 /* ignore truncated writes, datagrams might get lost */
1489 c->local_consumed += dlen + 4;
1490 len = write(c->wfd, buf, dlen);
1492 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1495 if (c->type != SSH_CHANNEL_OPEN)
1498 chan_write_failed(c);
1504 /* XXX: Later AIX versions can't push as much data to tty */
1505 if (compat20 && c->wfd_isatty)
1506 dlen = MIN(dlen, 8*1024);
1509 len = write(c->wfd, buf, dlen);
1510 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1513 if (c->type != SSH_CHANNEL_OPEN) {
1514 debug2("channel %d: not open", c->self);
1517 } else if (compat13) {
1518 buffer_clear(&c->output);
1519 debug2("channel %d: input draining.", c->self);
1520 c->type = SSH_CHANNEL_INPUT_DRAINING;
1522 chan_write_failed(c);
1526 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1527 if (tcgetattr(c->wfd, &tio) == 0 &&
1528 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1530 * Simulate echo to reduce the impact of
1531 * traffic analysis. We need to match the
1532 * size of a SSH2_MSG_CHANNEL_DATA message
1533 * (4 byte channel id + buf)
1535 packet_send_ignore(4 + len);
1539 buffer_consume(&c->output, len);
1540 if (compat20 && len > 0) {
1541 c->local_consumed += len;
1547 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1549 char buf[CHAN_RBUF];
1552 /** XXX handle drain efd, too */
1554 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1555 FD_ISSET(c->efd, writeset) &&
1556 buffer_len(&c->extended) > 0) {
1557 len = write(c->efd, buffer_ptr(&c->extended),
1558 buffer_len(&c->extended));
1559 debug2("channel %d: written %d to efd %d",
1560 c->self, len, c->efd);
1561 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1564 debug2("channel %d: closing write-efd %d",
1566 channel_close_fd(&c->efd);
1568 buffer_consume(&c->extended, len);
1569 c->local_consumed += len;
1571 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1572 FD_ISSET(c->efd, readset)) {
1573 len = read(c->efd, buf, sizeof(buf));
1574 debug2("channel %d: read %d from efd %d",
1575 c->self, len, c->efd);
1576 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1579 debug2("channel %d: closing read-efd %d",
1581 channel_close_fd(&c->efd);
1583 buffer_append(&c->extended, buf, len);
1590 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1595 /* Monitor control fd to detect if the slave client exits */
1596 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1597 len = read(c->ctl_fd, buf, sizeof(buf));
1598 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1601 debug2("channel %d: ctl read<=0", c->self);
1602 if (c->type != SSH_CHANNEL_OPEN) {
1603 debug2("channel %d: not open", c->self);
1607 chan_read_failed(c);
1608 chan_write_failed(c);
1612 fatal("%s: unexpected data on ctl fd", __func__);
1617 channel_check_window(Channel *c)
1619 if (c->type == SSH_CHANNEL_OPEN &&
1620 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1621 c->local_window < c->local_window_max/2 &&
1622 c->local_consumed > 0) {
1623 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1624 packet_put_int(c->remote_id);
1625 packet_put_int(c->local_consumed);
1627 debug2("channel %d: window %d sent adjust %d",
1628 c->self, c->local_window,
1630 c->local_window += c->local_consumed;
1631 c->local_consumed = 0;
1637 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1641 channel_handle_rfd(c, readset, writeset);
1642 channel_handle_wfd(c, readset, writeset);
1645 channel_handle_efd(c, readset, writeset);
1646 channel_handle_ctl(c, readset, writeset);
1647 channel_check_window(c);
1651 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1655 /* Send buffered output data to the socket. */
1656 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1657 len = write(c->sock, buffer_ptr(&c->output),
1658 buffer_len(&c->output));
1660 buffer_clear(&c->output);
1662 buffer_consume(&c->output, len);
1667 channel_handler_init_20(void)
1669 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1670 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1671 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1672 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1673 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1674 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1675 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1676 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1678 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1679 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1680 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1681 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1682 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1683 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1684 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1688 channel_handler_init_13(void)
1690 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1691 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1692 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1693 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1694 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1695 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1696 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1697 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1698 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1700 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1701 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1702 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1703 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1704 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1705 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1706 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1710 channel_handler_init_15(void)
1712 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1713 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1714 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1715 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1716 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1717 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1718 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1720 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1721 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1722 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1723 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1724 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1725 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1729 channel_handler_init(void)
1733 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1734 channel_pre[i] = NULL;
1735 channel_post[i] = NULL;
1738 channel_handler_init_20();
1740 channel_handler_init_13();
1742 channel_handler_init_15();
1745 /* gc dead channels */
1747 channel_garbage_collect(Channel *c)
1751 if (c->detach_user != NULL) {
1752 if (!chan_is_dead(c, c->detach_close))
1754 debug2("channel %d: gc: notify user", c->self);
1755 c->detach_user(c->self, NULL);
1756 /* if we still have a callback */
1757 if (c->detach_user != NULL)
1759 debug2("channel %d: gc: user detached", c->self);
1761 if (!chan_is_dead(c, 1))
1763 debug2("channel %d: garbage collecting", c->self);
1768 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1770 static int did_init = 0;
1775 channel_handler_init();
1778 for (i = 0; i < channels_alloc; i++) {
1782 if (ftab[c->type] != NULL)
1783 (*ftab[c->type])(c, readset, writeset);
1784 channel_garbage_collect(c);
1789 * Allocate/update select bitmasks and add any bits relevant to channels in
1793 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1794 u_int *nallocp, int rekeying)
1798 n = MAX(*maxfdp, channel_max_fd);
1800 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1801 /* perhaps check sz < nalloc/2 and shrink? */
1802 if (*readsetp == NULL || sz > *nallocp) {
1803 *readsetp = xrealloc(*readsetp, sz);
1804 *writesetp = xrealloc(*writesetp, sz);
1808 memset(*readsetp, 0, sz);
1809 memset(*writesetp, 0, sz);
1812 channel_handler(channel_pre, *readsetp, *writesetp);
1816 * After select, perform any appropriate operations for channels which have
1820 channel_after_select(fd_set * readset, fd_set * writeset)
1822 channel_handler(channel_post, readset, writeset);
1826 /* If there is data to send to the connection, enqueue some of it now. */
1829 channel_output_poll(void)
1834 for (i = 0; i < channels_alloc; i++) {
1840 * We are only interested in channels that can have buffered
1844 if (c->type != SSH_CHANNEL_OPEN &&
1845 c->type != SSH_CHANNEL_INPUT_DRAINING)
1848 if (c->type != SSH_CHANNEL_OPEN)
1852 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1853 /* XXX is this true? */
1854 debug3("channel %d: will not send data after close", c->self);
1858 /* Get the amount of buffered data for this channel. */
1859 if ((c->istate == CHAN_INPUT_OPEN ||
1860 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1861 (len = buffer_len(&c->input)) > 0) {
1867 data = buffer_get_string(&c->input,
1869 packet_start(SSH2_MSG_CHANNEL_DATA);
1870 packet_put_int(c->remote_id);
1871 packet_put_string(data, dlen);
1873 c->remote_window -= dlen + 4;
1879 * Send some data for the other side over the secure
1883 if (len > c->remote_window)
1884 len = c->remote_window;
1885 if (len > c->remote_maxpacket)
1886 len = c->remote_maxpacket;
1888 if (packet_is_interactive()) {
1892 /* Keep the packets at reasonable size. */
1893 if (len > packet_get_maxsize()/2)
1894 len = packet_get_maxsize()/2;
1898 packet_start(compat20 ?
1899 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1900 packet_put_int(c->remote_id);
1901 packet_put_string(buffer_ptr(&c->input), len);
1903 buffer_consume(&c->input, len);
1904 c->remote_window -= len;
1906 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1908 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1910 * input-buffer is empty and read-socket shutdown:
1911 * tell peer, that we will not send more data: send IEOF.
1912 * hack for extended data: delay EOF if EFD still in use.
1914 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1915 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1916 c->self, c->efd, buffer_len(&c->extended));
1920 /* Send extended data, i.e. stderr */
1922 !(c->flags & CHAN_EOF_SENT) &&
1923 c->remote_window > 0 &&
1924 (len = buffer_len(&c->extended)) > 0 &&
1925 c->extended_usage == CHAN_EXTENDED_READ) {
1926 debug2("channel %d: rwin %u elen %u euse %d",
1927 c->self, c->remote_window, buffer_len(&c->extended),
1929 if (len > c->remote_window)
1930 len = c->remote_window;
1931 if (len > c->remote_maxpacket)
1932 len = c->remote_maxpacket;
1933 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1934 packet_put_int(c->remote_id);
1935 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1936 packet_put_string(buffer_ptr(&c->extended), len);
1938 buffer_consume(&c->extended, len);
1939 c->remote_window -= len;
1940 debug2("channel %d: sent ext data %d", c->self, len);
1946 /* -- protocol input */
1949 channel_input_data(int type, u_int32_t seq, void *ctxt)
1956 /* Get the channel number and verify it. */
1957 id = packet_get_int();
1958 c = channel_lookup(id);
1960 packet_disconnect("Received data for nonexistent channel %d.", id);
1962 /* Ignore any data for non-open channels (might happen on close) */
1963 if (c->type != SSH_CHANNEL_OPEN &&
1964 c->type != SSH_CHANNEL_X11_OPEN)
1968 data = packet_get_string(&data_len);
1971 * Ignore data for protocol > 1.3 if output end is no longer open.
1972 * For protocol 2 the sending side is reducing its window as it sends
1973 * data, so we must 'fake' consumption of the data in order to ensure
1974 * that window updates are sent back. Otherwise the connection might
1977 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1979 c->local_window -= data_len;
1980 c->local_consumed += data_len;
1987 if (data_len > c->local_maxpacket) {
1988 logit("channel %d: rcvd big packet %d, maxpack %d",
1989 c->self, data_len, c->local_maxpacket);
1991 if (data_len > c->local_window) {
1992 logit("channel %d: rcvd too much data %d, win %d",
1993 c->self, data_len, c->local_window);
1997 c->local_window -= data_len;
2001 buffer_put_string(&c->output, data, data_len);
2003 buffer_append(&c->output, data, data_len);
2008 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2012 u_int data_len, tcode;
2015 /* Get the channel number and verify it. */
2016 id = packet_get_int();
2017 c = channel_lookup(id);
2020 packet_disconnect("Received extended_data for bad channel %d.", id);
2021 if (c->type != SSH_CHANNEL_OPEN) {
2022 logit("channel %d: ext data for non open", id);
2025 if (c->flags & CHAN_EOF_RCVD) {
2026 if (datafellows & SSH_BUG_EXTEOF)
2027 debug("channel %d: accepting ext data after eof", id);
2029 packet_disconnect("Received extended_data after EOF "
2030 "on channel %d.", id);
2032 tcode = packet_get_int();
2034 c->extended_usage != CHAN_EXTENDED_WRITE ||
2035 tcode != SSH2_EXTENDED_DATA_STDERR) {
2036 logit("channel %d: bad ext data", c->self);
2039 data = packet_get_string(&data_len);
2041 if (data_len > c->local_window) {
2042 logit("channel %d: rcvd too much extended_data %d, win %d",
2043 c->self, data_len, c->local_window);
2047 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2048 c->local_window -= data_len;
2049 buffer_append(&c->extended, data, data_len);
2054 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2059 id = packet_get_int();
2061 c = channel_lookup(id);
2063 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2066 /* XXX force input close */
2067 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2068 debug("channel %d: FORCE input drain", c->self);
2069 c->istate = CHAN_INPUT_WAIT_DRAIN;
2070 if (buffer_len(&c->input) == 0)
2077 channel_input_close(int type, u_int32_t seq, void *ctxt)
2082 id = packet_get_int();
2084 c = channel_lookup(id);
2086 packet_disconnect("Received close for nonexistent channel %d.", id);
2089 * Send a confirmation that we have closed the channel and no more
2090 * data is coming for it.
2092 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2093 packet_put_int(c->remote_id);
2097 * If the channel is in closed state, we have sent a close request,
2098 * and the other side will eventually respond with a confirmation.
2099 * Thus, we cannot free the channel here, because then there would be
2100 * no-one to receive the confirmation. The channel gets freed when
2101 * the confirmation arrives.
2103 if (c->type != SSH_CHANNEL_CLOSED) {
2105 * Not a closed channel - mark it as draining, which will
2106 * cause it to be freed later.
2108 buffer_clear(&c->input);
2109 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2113 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2115 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2117 int id = packet_get_int();
2118 Channel *c = channel_lookup(id);
2122 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2123 chan_rcvd_oclose(c);
2127 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2129 int id = packet_get_int();
2130 Channel *c = channel_lookup(id);
2134 packet_disconnect("Received close confirmation for "
2135 "out-of-range channel %d.", id);
2136 if (c->type != SSH_CHANNEL_CLOSED)
2137 packet_disconnect("Received close confirmation for "
2138 "non-closed channel %d (type %d).", id, c->type);
2143 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2148 id = packet_get_int();
2149 c = channel_lookup(id);
2151 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2152 packet_disconnect("Received open confirmation for "
2153 "non-opening channel %d.", id);
2154 remote_id = packet_get_int();
2155 /* Record the remote channel number and mark that the channel is now open. */
2156 c->remote_id = remote_id;
2157 c->type = SSH_CHANNEL_OPEN;
2160 c->remote_window = packet_get_int();
2161 c->remote_maxpacket = packet_get_int();
2163 debug2("callback start");
2164 c->confirm(c->self, c->confirm_ctx);
2165 debug2("callback done");
2167 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2168 c->remote_window, c->remote_maxpacket);
2174 reason2txt(int reason)
2177 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2178 return "administratively prohibited";
2179 case SSH2_OPEN_CONNECT_FAILED:
2180 return "connect failed";
2181 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2182 return "unknown channel type";
2183 case SSH2_OPEN_RESOURCE_SHORTAGE:
2184 return "resource shortage";
2186 return "unknown reason";
2190 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2193 char *msg = NULL, *lang = NULL;
2196 id = packet_get_int();
2197 c = channel_lookup(id);
2199 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2200 packet_disconnect("Received open failure for "
2201 "non-opening channel %d.", id);
2203 reason = packet_get_int();
2204 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2205 msg = packet_get_string(NULL);
2206 lang = packet_get_string(NULL);
2208 logit("channel %d: open failed: %s%s%s", id,
2209 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2216 /* Free the channel. This will also close the socket. */
2221 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2230 /* Get the channel number and verify it. */
2231 id = packet_get_int();
2232 c = channel_lookup(id);
2235 logit("Received window adjust for non-open channel %d.", id);
2238 adjust = packet_get_int();
2240 debug2("channel %d: rcvd adjust %u", id, adjust);
2241 c->remote_window += adjust;
2245 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2249 char *host, *originator_string;
2250 int remote_id, sock = -1;
2252 remote_id = packet_get_int();
2253 host = packet_get_string(NULL);
2254 host_port = packet_get_int();
2256 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2257 originator_string = packet_get_string(NULL);
2259 originator_string = xstrdup("unknown (remote did not supply name)");
2262 sock = channel_connect_to(host, host_port);
2264 c = channel_new("connected socket",
2265 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2266 originator_string, 1);
2267 c->remote_id = remote_id;
2269 xfree(originator_string);
2271 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2272 packet_put_int(remote_id);
2279 /* -- tcp forwarding */
2282 channel_set_af(int af)
2288 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2289 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2292 int sock, r, success = 0, wildcard = 0, is_client;
2293 struct addrinfo hints, *ai, *aitop;
2294 const char *host, *addr;
2295 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2297 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2298 listen_addr : host_to_connect;
2299 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2302 error("No forward host name.");
2305 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2306 error("Forward host name too long.");
2311 * Determine whether or not a port forward listens to loopback,
2312 * specified address or wildcard. On the client, a specified bind
2313 * address will always override gateway_ports. On the server, a
2314 * gateway_ports of 1 (``yes'') will override the client's
2315 * specification and force a wildcard bind, whereas a value of 2
2316 * (``clientspecified'') will bind to whatever address the client
2319 * Special-case listen_addrs are:
2321 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2322 * "" (empty string), "*" -> wildcard v4/v6
2323 * "localhost" -> loopback v4/v6
2326 if (listen_addr == NULL) {
2327 /* No address specified: default to gateway_ports setting */
2330 } else if (gateway_ports || is_client) {
2331 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2332 strcmp(listen_addr, "0.0.0.0") == 0) ||
2333 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2334 (!is_client && gateway_ports == 1))
2336 else if (strcmp(listen_addr, "localhost") != 0)
2340 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2341 type, wildcard, (addr == NULL) ? "NULL" : addr);
2344 * getaddrinfo returns a loopback address if the hostname is
2345 * set to NULL and hints.ai_flags is not AI_PASSIVE
2347 memset(&hints, 0, sizeof(hints));
2348 hints.ai_family = IPv4or6;
2349 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2350 hints.ai_socktype = SOCK_STREAM;
2351 snprintf(strport, sizeof strport, "%d", listen_port);
2352 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2354 /* This really shouldn't happen */
2355 packet_disconnect("getaddrinfo: fatal error: %s",
2358 error("channel_setup_fwd_listener: "
2359 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2364 for (ai = aitop; ai; ai = ai->ai_next) {
2365 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2367 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2368 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2369 error("channel_setup_fwd_listener: getnameinfo failed");
2372 /* Create a port to listen for the host. */
2373 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2375 /* this is no error since kernel may not support ipv6 */
2376 verbose("socket: %.100s", strerror(errno));
2380 channel_set_reuseaddr(sock);
2382 debug("Local forwarding listening on %s port %s.", ntop, strport);
2384 /* Bind the socket to the address. */
2385 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2386 /* address can be in use ipv6 address is already bound */
2388 error("bind: %.100s", strerror(errno));
2390 verbose("bind: %.100s", strerror(errno));
2395 /* Start listening for connections on the socket. */
2396 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2397 error("listen: %.100s", strerror(errno));
2401 /* Allocate a channel number for the socket. */
2402 c = channel_new("port listener", type, sock, sock, -1,
2403 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2404 0, "port listener", 1);
2405 strlcpy(c->path, host, sizeof(c->path));
2406 c->host_port = port_to_connect;
2407 c->listening_port = listen_port;
2411 error("channel_setup_fwd_listener: cannot listen to port: %d",
2413 freeaddrinfo(aitop);
2418 channel_cancel_rport_listener(const char *host, u_short port)
2423 for (i = 0; i < channels_alloc; i++) {
2424 Channel *c = channels[i];
2426 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2427 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2428 c->listening_port == port) {
2429 debug2("%s: close channel %d", __func__, i);
2438 /* protocol local port fwd, used by ssh (and sshd in v1) */
2440 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2441 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2443 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2444 listen_host, listen_port, host_to_connect, port_to_connect,
2448 /* protocol v2 remote port fwd, used by sshd */
2450 channel_setup_remote_fwd_listener(const char *listen_address,
2451 u_short listen_port, int gateway_ports)
2453 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2454 listen_address, listen_port, NULL, 0, gateway_ports);
2458 * Initiate forwarding of connections to port "port" on remote host through
2459 * the secure channel to host:port from local side.
2463 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2464 const char *host_to_connect, u_short port_to_connect)
2466 int type, success = 0;
2468 /* Record locally that connection to this host/port is permitted. */
2469 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2470 fatal("channel_request_remote_forwarding: too many forwards");
2472 /* Send the forward request to the remote side. */
2474 const char *address_to_bind;
2475 if (listen_host == NULL)
2476 address_to_bind = "localhost";
2477 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2478 address_to_bind = "";
2480 address_to_bind = listen_host;
2482 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2483 packet_put_cstring("tcpip-forward");
2484 packet_put_char(1); /* boolean: want reply */
2485 packet_put_cstring(address_to_bind);
2486 packet_put_int(listen_port);
2488 packet_write_wait();
2489 /* Assume that server accepts the request */
2492 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2493 packet_put_int(listen_port);
2494 packet_put_cstring(host_to_connect);
2495 packet_put_int(port_to_connect);
2497 packet_write_wait();
2499 /* Wait for response from the remote side. */
2500 type = packet_read();
2502 case SSH_SMSG_SUCCESS:
2505 case SSH_SMSG_FAILURE:
2506 logit("Warning: Server denied remote port forwarding.");
2509 /* Unknown packet */
2510 packet_disconnect("Protocol error for port forward request:"
2511 "received packet type %d.", type);
2515 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2516 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2517 permitted_opens[num_permitted_opens].listen_port = listen_port;
2518 num_permitted_opens++;
2523 * Request cancellation of remote forwarding of connection host:port from
2527 channel_request_rforward_cancel(const char *host, u_short port)
2534 for (i = 0; i < num_permitted_opens; i++) {
2535 if (permitted_opens[i].host_to_connect != NULL &&
2536 permitted_opens[i].listen_port == port)
2539 if (i >= num_permitted_opens) {
2540 debug("%s: requested forward not found", __func__);
2543 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2544 packet_put_cstring("cancel-tcpip-forward");
2546 packet_put_cstring(host == NULL ? "" : host);
2547 packet_put_int(port);
2550 permitted_opens[i].listen_port = 0;
2551 permitted_opens[i].port_to_connect = 0;
2552 xfree(permitted_opens[i].host_to_connect);
2553 permitted_opens[i].host_to_connect = NULL;
2557 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2558 * listening for the port, and sends back a success reply (or disconnect
2559 * message if there was an error). This never returns if there was an error.
2563 channel_input_port_forward_request(int is_root, int gateway_ports)
2565 u_short port, host_port;
2568 /* Get arguments from the packet. */
2569 port = packet_get_int();
2570 hostname = packet_get_string(NULL);
2571 host_port = packet_get_int();
2575 * Check that an unprivileged user is not trying to forward a
2578 if (port < IPPORT_RESERVED && !is_root)
2580 "Requested forwarding of port %d but user is not root.",
2583 packet_disconnect("Dynamic forwarding denied.");
2586 /* Initiate forwarding */
2587 channel_setup_local_fwd_listener(NULL, port, hostname,
2588 host_port, gateway_ports);
2590 /* Free the argument string. */
2595 * Permits opening to any host/port if permitted_opens[] is empty. This is
2596 * usually called by the server, because the user could connect to any port
2597 * anyway, and the server has no way to know but to trust the client anyway.
2600 channel_permit_all_opens(void)
2602 if (num_permitted_opens == 0)
2603 all_opens_permitted = 1;
2607 channel_add_permitted_opens(char *host, int port)
2609 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2610 fatal("channel_request_remote_forwarding: too many forwards");
2611 debug("allow port forwarding to host %s port %d", host, port);
2613 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2614 permitted_opens[num_permitted_opens].port_to_connect = port;
2615 num_permitted_opens++;
2617 all_opens_permitted = 0;
2621 channel_clear_permitted_opens(void)
2625 for (i = 0; i < num_permitted_opens; i++)
2626 if (permitted_opens[i].host_to_connect != NULL)
2627 xfree(permitted_opens[i].host_to_connect);
2628 num_permitted_opens = 0;
2633 /* return socket to remote host, port */
2635 connect_to(const char *host, u_short port)
2637 struct addrinfo hints, *ai, *aitop;
2638 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2642 memset(&hints, 0, sizeof(hints));
2643 hints.ai_family = IPv4or6;
2644 hints.ai_socktype = SOCK_STREAM;
2645 snprintf(strport, sizeof strport, "%d", port);
2646 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2647 error("connect_to %.100s: unknown host (%s)", host,
2648 gai_strerror(gaierr));
2651 for (ai = aitop; ai; ai = ai->ai_next) {
2652 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2654 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2655 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2656 error("connect_to: getnameinfo failed");
2659 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2661 if (ai->ai_next == NULL)
2662 error("socket: %.100s", strerror(errno));
2664 verbose("socket: %.100s", strerror(errno));
2667 if (set_nonblock(sock) == -1)
2668 fatal("%s: set_nonblock(%d)", __func__, sock);
2669 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2670 errno != EINPROGRESS) {
2671 error("connect_to %.100s port %s: %.100s", ntop, strport,
2674 continue; /* fail -- try next */
2676 break; /* success */
2679 freeaddrinfo(aitop);
2681 error("connect_to %.100s port %d: failed.", host, port);
2690 channel_connect_by_listen_address(u_short listen_port)
2694 for (i = 0; i < num_permitted_opens; i++)
2695 if (permitted_opens[i].host_to_connect != NULL &&
2696 permitted_opens[i].listen_port == listen_port)
2698 permitted_opens[i].host_to_connect,
2699 permitted_opens[i].port_to_connect);
2700 error("WARNING: Server requests forwarding for unknown listen_port %d",
2705 /* Check if connecting to that port is permitted and connect. */
2707 channel_connect_to(const char *host, u_short port)
2711 permit = all_opens_permitted;
2713 for (i = 0; i < num_permitted_opens; i++)
2714 if (permitted_opens[i].host_to_connect != NULL &&
2715 permitted_opens[i].port_to_connect == port &&
2716 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2721 logit("Received request to connect to host %.100s port %d, "
2722 "but the request was denied.", host, port);
2725 return connect_to(host, port);
2729 channel_send_window_changes(void)
2734 for (i = 0; i < channels_alloc; i++) {
2735 if (channels[i] == NULL || !channels[i]->client_tty ||
2736 channels[i]->type != SSH_CHANNEL_OPEN)
2738 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2740 channel_request_start(i, "window-change", 0);
2741 packet_put_int(ws.ws_col);
2742 packet_put_int(ws.ws_row);
2743 packet_put_int(ws.ws_xpixel);
2744 packet_put_int(ws.ws_ypixel);
2749 /* -- X11 forwarding */
2752 * Creates an internet domain socket for listening for X11 connections.
2753 * Returns 0 and a suitable display number for the DISPLAY variable
2754 * stored in display_numberp , or -1 if an error occurs.
2757 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2758 int single_connection, u_int *display_numberp, int **chanids)
2761 int display_number, sock;
2763 struct addrinfo hints, *ai, *aitop;
2764 char strport[NI_MAXSERV];
2765 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2767 if (chanids == NULL)
2770 for (display_number = x11_display_offset;
2771 display_number < MAX_DISPLAYS;
2773 port = 6000 + display_number;
2774 memset(&hints, 0, sizeof(hints));
2775 hints.ai_family = IPv4or6;
2776 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2777 hints.ai_socktype = SOCK_STREAM;
2778 snprintf(strport, sizeof strport, "%d", port);
2779 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2780 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2783 for (ai = aitop; ai; ai = ai->ai_next) {
2784 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2786 sock = socket(ai->ai_family, ai->ai_socktype,
2789 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2790 error("socket: %.100s", strerror(errno));
2791 freeaddrinfo(aitop);
2794 debug("x11_create_display_inet: Socket family %d not supported",
2800 if (ai->ai_family == AF_INET6) {
2802 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2803 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2806 channel_set_reuseaddr(sock);
2807 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2808 debug2("bind port %d: %.100s", port, strerror(errno));
2814 for (n = 0; n < num_socks; n++) {
2820 socks[num_socks++] = sock;
2821 #ifndef DONT_TRY_OTHER_AF
2822 if (num_socks == NUM_SOCKS)
2825 if (x11_use_localhost) {
2826 if (num_socks == NUM_SOCKS)
2833 freeaddrinfo(aitop);
2837 if (display_number >= MAX_DISPLAYS) {
2838 error("Failed to allocate internet-domain X11 display socket.");
2841 /* Start listening for connections on the socket. */
2842 for (n = 0; n < num_socks; n++) {
2844 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2845 error("listen: %.100s", strerror(errno));
2851 /* Allocate a channel for each socket. */
2852 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
2853 for (n = 0; n < num_socks; n++) {
2855 nc = channel_new("x11 listener",
2856 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2857 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2858 0, "X11 inet listener", 1);
2859 nc->single_connection = single_connection;
2860 (*chanids)[n] = nc->self;
2864 /* Return the display number for the DISPLAY environment variable. */
2865 *display_numberp = display_number;
2870 connect_local_xsocket(u_int dnr)
2873 struct sockaddr_un addr;
2875 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2877 error("socket: %.100s", strerror(errno));
2878 memset(&addr, 0, sizeof(addr));
2879 addr.sun_family = AF_UNIX;
2880 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2881 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2884 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2889 x11_connect_display(void)
2891 int display_number, sock = 0;
2892 const char *display;
2893 char buf[1024], *cp;
2894 struct addrinfo hints, *ai, *aitop;
2895 char strport[NI_MAXSERV];
2898 /* Try to open a socket for the local X server. */
2899 display = getenv("DISPLAY");
2901 error("DISPLAY not set.");
2905 * Now we decode the value of the DISPLAY variable and make a
2906 * connection to the real X server.
2910 * Check if it is a unix domain socket. Unix domain displays are in
2911 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2913 if (strncmp(display, "unix:", 5) == 0 ||
2914 display[0] == ':') {
2915 /* Connect to the unix domain socket. */
2916 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2917 error("Could not parse display number from DISPLAY: %.100s",
2921 /* Create a socket. */
2922 sock = connect_local_xsocket(display_number);
2926 /* OK, we now have a connection to the display. */
2930 * Connect to an inet socket. The DISPLAY value is supposedly
2931 * hostname:d[.s], where hostname may also be numeric IP address.
2933 strlcpy(buf, display, sizeof(buf));
2934 cp = strchr(buf, ':');
2936 error("Could not find ':' in DISPLAY: %.100s", display);
2940 /* buf now contains the host name. But first we parse the display number. */
2941 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2942 error("Could not parse display number from DISPLAY: %.100s",
2947 /* Look up the host address */
2948 memset(&hints, 0, sizeof(hints));
2949 hints.ai_family = IPv4or6;
2950 hints.ai_socktype = SOCK_STREAM;
2951 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2952 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2953 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2956 for (ai = aitop; ai; ai = ai->ai_next) {
2957 /* Create a socket. */
2958 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2960 debug2("socket: %.100s", strerror(errno));
2963 /* Connect it to the display. */
2964 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2965 debug2("connect %.100s port %d: %.100s", buf,
2966 6000 + display_number, strerror(errno));
2973 freeaddrinfo(aitop);
2975 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2984 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2985 * the remote channel number. We should do whatever we want, and respond
2986 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2990 x11_input_open(int type, u_int32_t seq, void *ctxt)
2993 int remote_id, sock = 0;
2996 debug("Received X11 open request.");
2998 remote_id = packet_get_int();
3000 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3001 remote_host = packet_get_string(NULL);
3003 remote_host = xstrdup("unknown (remote did not supply name)");
3007 /* Obtain a connection to the real X display. */
3008 sock = x11_connect_display();
3010 /* Allocate a channel for this connection. */
3011 c = channel_new("connected x11 socket",
3012 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3014 c->remote_id = remote_id;
3019 /* Send refusal to the remote host. */
3020 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3021 packet_put_int(remote_id);
3023 /* Send a confirmation to the remote host. */
3024 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3025 packet_put_int(remote_id);
3026 packet_put_int(c->self);
3031 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3033 deny_input_open(int type, u_int32_t seq, void *ctxt)
3035 int rchan = packet_get_int();
3038 case SSH_SMSG_AGENT_OPEN:
3039 error("Warning: ssh server tried agent forwarding.");
3041 case SSH_SMSG_X11_OPEN:
3042 error("Warning: ssh server tried X11 forwarding.");
3045 error("deny_input_open: type %d", type);
3048 error("Warning: this is probably a break-in attempt by a malicious server.");
3049 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3050 packet_put_int(rchan);
3055 * Requests forwarding of X11 connections, generates fake authentication
3056 * data, and enables authentication spoofing.
3057 * This should be called in the client only.
3060 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3061 const char *proto, const char *data)
3063 u_int data_len = (u_int) strlen(data) / 2;
3070 if (x11_saved_display == NULL)
3071 x11_saved_display = xstrdup(disp);
3072 else if (strcmp(disp, x11_saved_display) != 0) {
3073 error("x11_request_forwarding_with_spoofing: different "
3074 "$DISPLAY already forwarded");
3080 cp = strchr(disp, ':');
3082 cp = strchr(cp, '.');
3084 screen_number = atoi(cp + 1);
3088 if (x11_saved_proto == NULL) {
3089 /* Save protocol name. */
3090 x11_saved_proto = xstrdup(proto);
3092 * Extract real authentication data and generate fake data
3093 * of the same length.
3095 x11_saved_data = xmalloc(data_len);
3096 x11_fake_data = xmalloc(data_len);
3097 for (i = 0; i < data_len; i++) {
3098 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3099 fatal("x11_request_forwarding: bad "
3100 "authentication data: %.100s", data);
3103 x11_saved_data[i] = value;
3104 x11_fake_data[i] = rnd & 0xff;
3107 x11_saved_data_len = data_len;
3108 x11_fake_data_len = data_len;
3111 /* Convert the fake data into hex. */
3112 new_data = tohex(x11_fake_data, data_len);
3114 /* Send the request packet. */
3116 channel_request_start(client_session_id, "x11-req", 0);
3117 packet_put_char(0); /* XXX bool single connection */
3119 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3121 packet_put_cstring(proto);
3122 packet_put_cstring(new_data);
3123 packet_put_int(screen_number);
3125 packet_write_wait();
3130 /* -- agent forwarding */
3132 /* Sends a message to the server to request authentication fd forwarding. */
3135 auth_request_forwarding(void)
3137 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3139 packet_write_wait();