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:
187 logit("Non-public channel %d, type %d.", id, c->type);
192 * Register filedescriptors for a channel, used when allocating a channel or
193 * when the channel consumer/producer is ready, e.g. shell exec'd
197 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
198 int extusage, int nonblock)
200 /* Update the maximum file descriptor value. */
201 channel_max_fd = MAX(channel_max_fd, rfd);
202 channel_max_fd = MAX(channel_max_fd, wfd);
203 channel_max_fd = MAX(channel_max_fd, efd);
205 /* XXX set close-on-exec -markus */
209 c->sock = (rfd == wfd) ? rfd : -1;
210 c->ctl_fd = -1; /* XXX: set elsewhere */
212 c->extended_usage = extusage;
214 /* XXX ugly hack: nonblock is only set by the server */
215 if (nonblock && isatty(c->rfd)) {
216 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
218 if (!isatty(c->wfd)) {
219 error("channel %d: wfd %d is not a tty?",
225 c->wfd_isatty = isatty(c->wfd);
227 /* enable nonblocking mode */
239 * Allocate a new channel object and set its type and socket. This will cause
240 * remote_name to be freed.
244 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
245 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
251 /* Do initial allocation if this is the first call. */
252 if (channels_alloc == 0) {
254 channels = xmalloc(channels_alloc * sizeof(Channel *));
255 for (i = 0; i < channels_alloc; i++)
258 /* Try to find a free slot where to put the new channel. */
259 for (found = -1, i = 0; i < channels_alloc; i++)
260 if (channels[i] == NULL) {
261 /* Found a free slot. */
266 /* There are no free slots. Take last+1 slot and expand the array. */
267 found = channels_alloc;
268 if (channels_alloc > 10000)
269 fatal("channel_new: internal error: channels_alloc %d "
270 "too big.", channels_alloc);
271 channels = xrealloc(channels,
272 (channels_alloc + 10) * sizeof(Channel *));
273 channels_alloc += 10;
274 debug2("channel: expanding %d", channels_alloc);
275 for (i = found; i < channels_alloc; i++)
278 /* Initialize and return new channel. */
279 c = channels[found] = xmalloc(sizeof(Channel));
280 memset(c, 0, sizeof(Channel));
281 buffer_init(&c->input);
282 buffer_init(&c->output);
283 buffer_init(&c->extended);
284 c->ostate = CHAN_OUTPUT_OPEN;
285 c->istate = CHAN_INPUT_OPEN;
287 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
291 c->local_window = window;
292 c->local_window_max = window;
293 c->local_consumed = 0;
294 c->local_maxpacket = maxpack;
296 c->remote_name = xstrdup(remote_name);
297 c->remote_window = 0;
298 c->remote_maxpacket = 0;
300 c->single_connection = 0;
301 c->detach_user = NULL;
304 c->confirm_ctx = NULL;
305 c->input_filter = NULL;
306 c->output_filter = NULL;
307 debug("channel %d: new [%s]", found, remote_name);
312 channel_find_maxfd(void)
318 for (i = 0; i < channels_alloc; i++) {
321 max = MAX(max, c->rfd);
322 max = MAX(max, c->wfd);
323 max = MAX(max, c->efd);
330 channel_close_fd(int *fdp)
332 int ret = 0, fd = *fdp;
337 if (fd == channel_max_fd)
338 channel_max_fd = channel_find_maxfd();
343 /* Close all channel fd/socket. */
346 channel_close_fds(Channel *c)
348 debug3("channel %d: close_fds r %d w %d e %d c %d",
349 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
351 channel_close_fd(&c->sock);
352 channel_close_fd(&c->ctl_fd);
353 channel_close_fd(&c->rfd);
354 channel_close_fd(&c->wfd);
355 channel_close_fd(&c->efd);
358 /* Free the channel and close its fd/socket. */
361 channel_free(Channel *c)
366 for (n = 0, i = 0; i < channels_alloc; i++)
369 debug("channel %d: free: %s, nchannels %u", c->self,
370 c->remote_name ? c->remote_name : "???", n);
372 s = channel_open_message();
373 debug3("channel %d: status: %s", c->self, s);
377 shutdown(c->sock, SHUT_RDWR);
379 shutdown(c->ctl_fd, SHUT_RDWR);
380 channel_close_fds(c);
381 buffer_free(&c->input);
382 buffer_free(&c->output);
383 buffer_free(&c->extended);
384 if (c->remote_name) {
385 xfree(c->remote_name);
386 c->remote_name = NULL;
388 channels[c->self] = NULL;
393 channel_free_all(void)
397 for (i = 0; i < channels_alloc; i++)
398 if (channels[i] != NULL)
399 channel_free(channels[i]);
403 * Closes the sockets/fds of all channels. This is used to close extra file
404 * descriptors after a fork.
408 channel_close_all(void)
412 for (i = 0; i < channels_alloc; i++)
413 if (channels[i] != NULL)
414 channel_close_fds(channels[i]);
418 * Stop listening to channels.
422 channel_stop_listening(void)
427 for (i = 0; i < channels_alloc; i++) {
431 case SSH_CHANNEL_AUTH_SOCKET:
432 case SSH_CHANNEL_PORT_LISTENER:
433 case SSH_CHANNEL_RPORT_LISTENER:
434 case SSH_CHANNEL_X11_LISTENER:
435 channel_close_fd(&c->sock);
444 * Returns true if no channel has too much buffered data, and false if one or
445 * more channel is overfull.
449 channel_not_very_much_buffered_data(void)
454 for (i = 0; i < channels_alloc; i++) {
456 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
459 buffer_len(&c->input) > packet_get_maxsize()) {
460 debug2("channel %d: big input buffer %d",
461 c->self, buffer_len(&c->input));
465 if (buffer_len(&c->output) > packet_get_maxsize()) {
466 debug2("channel %d: big output buffer %u > %u",
467 c->self, buffer_len(&c->output),
468 packet_get_maxsize());
476 /* Returns true if any channel is still open. */
479 channel_still_open(void)
484 for (i = 0; i < channels_alloc; i++) {
489 case SSH_CHANNEL_X11_LISTENER:
490 case SSH_CHANNEL_PORT_LISTENER:
491 case SSH_CHANNEL_RPORT_LISTENER:
492 case SSH_CHANNEL_CLOSED:
493 case SSH_CHANNEL_AUTH_SOCKET:
494 case SSH_CHANNEL_DYNAMIC:
495 case SSH_CHANNEL_CONNECTING:
496 case SSH_CHANNEL_ZOMBIE:
498 case SSH_CHANNEL_LARVAL:
500 fatal("cannot happen: SSH_CHANNEL_LARVAL");
502 case SSH_CHANNEL_OPENING:
503 case SSH_CHANNEL_OPEN:
504 case SSH_CHANNEL_X11_OPEN:
506 case SSH_CHANNEL_INPUT_DRAINING:
507 case SSH_CHANNEL_OUTPUT_DRAINING:
509 fatal("cannot happen: OUT_DRAIN");
512 fatal("channel_still_open: bad channel type %d", c->type);
519 /* Returns the id of an open channel suitable for keepaliving */
522 channel_find_open(void)
527 for (i = 0; i < channels_alloc; i++) {
529 if (c == NULL || c->remote_id < 0)
532 case SSH_CHANNEL_CLOSED:
533 case SSH_CHANNEL_DYNAMIC:
534 case SSH_CHANNEL_X11_LISTENER:
535 case SSH_CHANNEL_PORT_LISTENER:
536 case SSH_CHANNEL_RPORT_LISTENER:
537 case SSH_CHANNEL_OPENING:
538 case SSH_CHANNEL_CONNECTING:
539 case SSH_CHANNEL_ZOMBIE:
541 case SSH_CHANNEL_LARVAL:
542 case SSH_CHANNEL_AUTH_SOCKET:
543 case SSH_CHANNEL_OPEN:
544 case SSH_CHANNEL_X11_OPEN:
546 case SSH_CHANNEL_INPUT_DRAINING:
547 case SSH_CHANNEL_OUTPUT_DRAINING:
549 fatal("cannot happen: OUT_DRAIN");
552 fatal("channel_find_open: bad channel type %d", c->type);
561 * Returns a message describing the currently open forwarded connections,
562 * suitable for sending to the client. The message contains crlf pairs for
567 channel_open_message(void)
574 buffer_init(&buffer);
575 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
576 buffer_append(&buffer, buf, strlen(buf));
577 for (i = 0; i < channels_alloc; i++) {
582 case SSH_CHANNEL_X11_LISTENER:
583 case SSH_CHANNEL_PORT_LISTENER:
584 case SSH_CHANNEL_RPORT_LISTENER:
585 case SSH_CHANNEL_CLOSED:
586 case SSH_CHANNEL_AUTH_SOCKET:
587 case SSH_CHANNEL_ZOMBIE:
589 case SSH_CHANNEL_LARVAL:
590 case SSH_CHANNEL_OPENING:
591 case SSH_CHANNEL_CONNECTING:
592 case SSH_CHANNEL_DYNAMIC:
593 case SSH_CHANNEL_OPEN:
594 case SSH_CHANNEL_X11_OPEN:
595 case SSH_CHANNEL_INPUT_DRAINING:
596 case SSH_CHANNEL_OUTPUT_DRAINING:
597 snprintf(buf, sizeof buf,
598 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
599 c->self, c->remote_name,
600 c->type, c->remote_id,
601 c->istate, buffer_len(&c->input),
602 c->ostate, buffer_len(&c->output),
603 c->rfd, c->wfd, c->ctl_fd);
604 buffer_append(&buffer, buf, strlen(buf));
607 fatal("channel_open_message: bad channel type %d", c->type);
611 buffer_append(&buffer, "\0", 1);
612 cp = xstrdup(buffer_ptr(&buffer));
613 buffer_free(&buffer);
618 channel_send_open(int id)
620 Channel *c = channel_lookup(id);
623 logit("channel_send_open: %d: bad id", id);
626 debug2("channel %d: send open", id);
627 packet_start(SSH2_MSG_CHANNEL_OPEN);
628 packet_put_cstring(c->ctype);
629 packet_put_int(c->self);
630 packet_put_int(c->local_window);
631 packet_put_int(c->local_maxpacket);
636 channel_request_start(int id, char *service, int wantconfirm)
638 Channel *c = channel_lookup(id);
641 logit("channel_request_start: %d: unknown channel id", id);
644 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
645 packet_start(SSH2_MSG_CHANNEL_REQUEST);
646 packet_put_int(c->remote_id);
647 packet_put_cstring(service);
648 packet_put_char(wantconfirm);
651 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
653 Channel *c = channel_lookup(id);
656 logit("channel_register_comfirm: %d: bad id", id);
660 c->confirm_ctx = ctx;
663 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
665 Channel *c = channel_by_id(id);
668 logit("channel_register_cleanup: %d: bad id", id);
672 c->detach_close = do_close;
675 channel_cancel_cleanup(int id)
677 Channel *c = channel_by_id(id);
680 logit("channel_cancel_cleanup: %d: bad id", id);
683 c->detach_user = NULL;
687 channel_register_filter(int id, channel_infilter_fn *ifn,
688 channel_outfilter_fn *ofn)
690 Channel *c = channel_lookup(id);
693 logit("channel_register_filter: %d: bad id", id);
696 c->input_filter = ifn;
697 c->output_filter = ofn;
701 channel_set_fds(int id, int rfd, int wfd, int efd,
702 int extusage, int nonblock, u_int window_max)
704 Channel *c = channel_lookup(id);
706 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
707 fatal("channel_activate for non-larval channel %d.", id);
708 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
709 c->type = SSH_CHANNEL_OPEN;
710 c->local_window = c->local_window_max = window_max;
711 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
712 packet_put_int(c->remote_id);
713 packet_put_int(c->local_window);
718 * 'channel_pre*' are called just before select() to add any bits relevant to
719 * channels in the select bitmasks.
722 * 'channel_post*': perform any appropriate operations for channels which
723 * have events pending.
725 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
726 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
727 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
730 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
732 FD_SET(c->sock, readset);
736 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
738 debug3("channel %d: waiting for connection", c->self);
739 FD_SET(c->sock, writeset);
743 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
745 if (buffer_len(&c->input) < packet_get_maxsize())
746 FD_SET(c->sock, readset);
747 if (buffer_len(&c->output) > 0)
748 FD_SET(c->sock, writeset);
752 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
754 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
756 /* check buffer limits */
757 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
759 if (c->istate == CHAN_INPUT_OPEN &&
761 buffer_len(&c->input) < limit)
762 FD_SET(c->rfd, readset);
763 if (c->ostate == CHAN_OUTPUT_OPEN ||
764 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
765 if (buffer_len(&c->output) > 0) {
766 FD_SET(c->wfd, writeset);
767 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
768 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
769 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
770 c->self, c->efd, buffer_len(&c->extended));
775 /** XXX check close conditions, too */
776 if (compat20 && c->efd != -1) {
777 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
778 buffer_len(&c->extended) > 0)
779 FD_SET(c->efd, writeset);
780 else if (!(c->flags & CHAN_EOF_SENT) &&
781 c->extended_usage == CHAN_EXTENDED_READ &&
782 buffer_len(&c->extended) < c->remote_window)
783 FD_SET(c->efd, readset);
785 /* XXX: What about efd? races? */
786 if (compat20 && c->ctl_fd != -1 &&
787 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
788 FD_SET(c->ctl_fd, readset);
792 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
794 if (buffer_len(&c->input) == 0) {
795 packet_start(SSH_MSG_CHANNEL_CLOSE);
796 packet_put_int(c->remote_id);
798 c->type = SSH_CHANNEL_CLOSED;
799 debug2("channel %d: closing after input drain.", c->self);
804 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
806 if (buffer_len(&c->output) == 0)
809 FD_SET(c->sock, writeset);
813 * This is a special state for X11 authentication spoofing. An opened X11
814 * connection (when authentication spoofing is being done) remains in this
815 * state until the first packet has been completely read. The authentication
816 * data in that packet is then substituted by the real data if it matches the
817 * fake data, and the channel is put into normal mode.
818 * XXX All this happens at the client side.
819 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
822 x11_open_helper(Buffer *b)
825 u_int proto_len, data_len;
827 /* Check if the fixed size part of the packet is in buffer. */
828 if (buffer_len(b) < 12)
831 /* Parse the lengths of variable-length fields. */
833 if (ucp[0] == 0x42) { /* Byte order MSB first. */
834 proto_len = 256 * ucp[6] + ucp[7];
835 data_len = 256 * ucp[8] + ucp[9];
836 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
837 proto_len = ucp[6] + 256 * ucp[7];
838 data_len = ucp[8] + 256 * ucp[9];
840 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
845 /* Check if the whole packet is in buffer. */
847 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
850 /* Check if authentication protocol matches. */
851 if (proto_len != strlen(x11_saved_proto) ||
852 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
853 debug2("X11 connection uses different authentication protocol.");
856 /* Check if authentication data matches our fake data. */
857 if (data_len != x11_fake_data_len ||
858 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
859 x11_fake_data, x11_fake_data_len) != 0) {
860 debug2("X11 auth data does not match fake data.");
863 /* Check fake data length */
864 if (x11_fake_data_len != x11_saved_data_len) {
865 error("X11 fake_data_len %d != saved_data_len %d",
866 x11_fake_data_len, x11_saved_data_len);
870 * Received authentication protocol and data match
871 * our fake data. Substitute the fake data with real
874 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
875 x11_saved_data, x11_saved_data_len);
880 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
882 int ret = x11_open_helper(&c->output);
885 /* Start normal processing for the channel. */
886 c->type = SSH_CHANNEL_OPEN;
887 channel_pre_open_13(c, readset, writeset);
888 } else if (ret == -1) {
890 * We have received an X11 connection that has bad
891 * authentication information.
893 logit("X11 connection rejected because of wrong authentication.");
894 buffer_clear(&c->input);
895 buffer_clear(&c->output);
896 channel_close_fd(&c->sock);
898 c->type = SSH_CHANNEL_CLOSED;
899 packet_start(SSH_MSG_CHANNEL_CLOSE);
900 packet_put_int(c->remote_id);
906 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
908 int ret = x11_open_helper(&c->output);
910 /* c->force_drain = 1; */
913 c->type = SSH_CHANNEL_OPEN;
914 channel_pre_open(c, readset, writeset);
915 } else if (ret == -1) {
916 logit("X11 connection rejected because of wrong authentication.");
917 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
919 buffer_clear(&c->input);
921 buffer_clear(&c->output);
922 /* for proto v1, the peer will send an IEOF */
924 chan_write_failed(c);
926 c->type = SSH_CHANNEL_OPEN;
927 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
931 /* try to decode a socks4 header */
933 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
936 u_int len, have, i, found;
942 struct in_addr dest_addr;
945 debug2("channel %d: decode socks4", c->self);
947 have = buffer_len(&c->input);
948 len = sizeof(s4_req);
951 p = buffer_ptr(&c->input);
952 for (found = 0, i = len; i < have; i++) {
958 /* the peer is probably sending garbage */
959 debug("channel %d: decode socks4: too long",
966 buffer_get(&c->input, (char *)&s4_req.version, 1);
967 buffer_get(&c->input, (char *)&s4_req.command, 1);
968 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
969 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
970 have = buffer_len(&c->input);
971 p = buffer_ptr(&c->input);
973 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
975 fatal("channel %d: decode socks4: len %d > have %d",
977 strlcpy(username, p, sizeof(username));
978 buffer_consume(&c->input, len);
979 buffer_consume(&c->input, 1); /* trailing '\0' */
981 host = inet_ntoa(s4_req.dest_addr);
982 strlcpy(c->path, host, sizeof(c->path));
983 c->host_port = ntohs(s4_req.dest_port);
985 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
986 c->self, host, c->host_port, s4_req.command);
988 if (s4_req.command != 1) {
989 debug("channel %d: cannot handle: socks4 cn %d",
990 c->self, s4_req.command);
993 s4_rsp.version = 0; /* vn: 0 for reply */
994 s4_rsp.command = 90; /* cd: req granted */
995 s4_rsp.dest_port = 0; /* ignored */
996 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
997 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
1001 /* try to decode a socks5 header */
1002 #define SSH_SOCKS5_AUTHDONE 0x1000
1003 #define SSH_SOCKS5_NOAUTH 0x00
1004 #define SSH_SOCKS5_IPV4 0x01
1005 #define SSH_SOCKS5_DOMAIN 0x03
1006 #define SSH_SOCKS5_IPV6 0x04
1007 #define SSH_SOCKS5_CONNECT 0x01
1008 #define SSH_SOCKS5_SUCCESS 0x00
1011 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1019 u_int16_t dest_port;
1020 u_char *p, dest_addr[255+1];
1021 u_int have, i, found, nmethods, addrlen, af;
1023 debug2("channel %d: decode socks5", c->self);
1024 p = buffer_ptr(&c->input);
1027 have = buffer_len(&c->input);
1028 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1029 /* format: ver | nmethods | methods */
1033 if (have < nmethods + 2)
1035 /* look for method: "NO AUTHENTICATION REQUIRED" */
1036 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1037 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1043 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1047 buffer_consume(&c->input, nmethods + 2);
1048 buffer_put_char(&c->output, 0x05); /* version */
1049 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1050 FD_SET(c->sock, writeset);
1051 c->flags |= SSH_SOCKS5_AUTHDONE;
1052 debug2("channel %d: socks5 auth done", c->self);
1053 return 0; /* need more */
1055 debug2("channel %d: socks5 post auth", c->self);
1056 if (have < sizeof(s5_req)+1)
1057 return 0; /* need more */
1058 memcpy((char *)&s5_req, p, sizeof(s5_req));
1059 if (s5_req.version != 0x05 ||
1060 s5_req.command != SSH_SOCKS5_CONNECT ||
1061 s5_req.reserved != 0x00) {
1062 debug2("channel %d: only socks5 connect supported", c->self);
1065 switch (s5_req.atyp){
1066 case SSH_SOCKS5_IPV4:
1070 case SSH_SOCKS5_DOMAIN:
1071 addrlen = p[sizeof(s5_req)];
1074 case SSH_SOCKS5_IPV6:
1079 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1082 if (have < 4 + addrlen + 2)
1084 buffer_consume(&c->input, sizeof(s5_req));
1085 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1086 buffer_consume(&c->input, 1); /* host string length */
1087 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1088 buffer_get(&c->input, (char *)&dest_port, 2);
1089 dest_addr[addrlen] = '\0';
1090 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1091 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1092 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1094 c->host_port = ntohs(dest_port);
1096 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1097 c->self, c->path, c->host_port, s5_req.command);
1099 s5_rsp.version = 0x05;
1100 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1101 s5_rsp.reserved = 0; /* ignored */
1102 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1103 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1104 dest_port = 0; /* ignored */
1106 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1107 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1108 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1112 /* dynamic port forwarding */
1114 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1120 have = buffer_len(&c->input);
1122 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1123 /* buffer_dump(&c->input); */
1124 /* check if the fixed size part of the packet is in buffer. */
1127 FD_SET(c->sock, readset);
1130 /* try to guess the protocol */
1131 p = buffer_ptr(&c->input);
1134 ret = channel_decode_socks4(c, readset, writeset);
1137 ret = channel_decode_socks5(c, readset, writeset);
1145 } else if (ret == 0) {
1146 debug2("channel %d: pre_dynamic: need more", c->self);
1148 FD_SET(c->sock, readset);
1150 /* switch to the next state */
1151 c->type = SSH_CHANNEL_OPENING;
1152 port_open_helper(c, "direct-tcpip");
1156 /* This is our fake X11 server socket. */
1158 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1161 struct sockaddr addr;
1164 char buf[16384], *remote_ipaddr;
1167 if (FD_ISSET(c->sock, readset)) {
1168 debug("X11 connection requested.");
1169 addrlen = sizeof(addr);
1170 newsock = accept(c->sock, &addr, &addrlen);
1171 if (c->single_connection) {
1172 debug2("single_connection: closing X11 listener.");
1173 channel_close_fd(&c->sock);
1177 error("accept: %.100s", strerror(errno));
1180 set_nodelay(newsock);
1181 remote_ipaddr = get_peer_ipaddr(newsock);
1182 remote_port = get_peer_port(newsock);
1183 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1184 remote_ipaddr, remote_port);
1186 nc = channel_new("accepted x11 socket",
1187 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1188 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1190 packet_start(SSH2_MSG_CHANNEL_OPEN);
1191 packet_put_cstring("x11");
1192 packet_put_int(nc->self);
1193 packet_put_int(nc->local_window_max);
1194 packet_put_int(nc->local_maxpacket);
1195 /* originator ipaddr and port */
1196 packet_put_cstring(remote_ipaddr);
1197 if (datafellows & SSH_BUG_X11FWD) {
1198 debug2("ssh2 x11 bug compat mode");
1200 packet_put_int(remote_port);
1204 packet_start(SSH_SMSG_X11_OPEN);
1205 packet_put_int(nc->self);
1206 if (packet_get_protocol_flags() &
1207 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1208 packet_put_cstring(buf);
1211 xfree(remote_ipaddr);
1216 port_open_helper(Channel *c, char *rtype)
1220 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1221 int remote_port = get_peer_port(c->sock);
1223 direct = (strcmp(rtype, "direct-tcpip") == 0);
1225 snprintf(buf, sizeof buf,
1226 "%s: listening port %d for %.100s port %d, "
1227 "connect from %.200s port %d",
1228 rtype, c->listening_port, c->path, c->host_port,
1229 remote_ipaddr, remote_port);
1231 xfree(c->remote_name);
1232 c->remote_name = xstrdup(buf);
1235 packet_start(SSH2_MSG_CHANNEL_OPEN);
1236 packet_put_cstring(rtype);
1237 packet_put_int(c->self);
1238 packet_put_int(c->local_window_max);
1239 packet_put_int(c->local_maxpacket);
1241 /* target host, port */
1242 packet_put_cstring(c->path);
1243 packet_put_int(c->host_port);
1245 /* listen address, port */
1246 packet_put_cstring(c->path);
1247 packet_put_int(c->listening_port);
1249 /* originator host and port */
1250 packet_put_cstring(remote_ipaddr);
1251 packet_put_int((u_int)remote_port);
1254 packet_start(SSH_MSG_PORT_OPEN);
1255 packet_put_int(c->self);
1256 packet_put_cstring(c->path);
1257 packet_put_int(c->host_port);
1258 if (packet_get_protocol_flags() &
1259 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1260 packet_put_cstring(c->remote_name);
1263 xfree(remote_ipaddr);
1267 channel_set_reuseaddr(int fd)
1272 * Set socket options.
1273 * Allow local port reuse in TIME_WAIT.
1275 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1276 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1280 * This socket is listening for connections to a forwarded TCP/IP port.
1283 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1286 struct sockaddr addr;
1287 int newsock, nextstate;
1291 if (FD_ISSET(c->sock, readset)) {
1292 debug("Connection to port %d forwarding "
1293 "to %.100s port %d requested.",
1294 c->listening_port, c->path, c->host_port);
1296 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1297 nextstate = SSH_CHANNEL_OPENING;
1298 rtype = "forwarded-tcpip";
1300 if (c->host_port == 0) {
1301 nextstate = SSH_CHANNEL_DYNAMIC;
1302 rtype = "dynamic-tcpip";
1304 nextstate = SSH_CHANNEL_OPENING;
1305 rtype = "direct-tcpip";
1309 addrlen = sizeof(addr);
1310 newsock = accept(c->sock, &addr, &addrlen);
1312 error("accept: %.100s", strerror(errno));
1315 set_nodelay(newsock);
1316 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1317 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1318 nc->listening_port = c->listening_port;
1319 nc->host_port = c->host_port;
1320 strlcpy(nc->path, c->path, sizeof(nc->path));
1322 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1324 * do not call the channel_post handler until
1325 * this flag has been reset by a pre-handler.
1326 * otherwise the FD_ISSET calls might overflow
1330 port_open_helper(nc, rtype);
1336 * This is the authentication agent socket listening for connections from
1340 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1344 struct sockaddr addr;
1347 if (FD_ISSET(c->sock, readset)) {
1348 addrlen = sizeof(addr);
1349 newsock = accept(c->sock, &addr, &addrlen);
1351 error("accept from auth socket: %.100s", strerror(errno));
1354 nc = channel_new("accepted auth socket",
1355 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1356 c->local_window_max, c->local_maxpacket,
1357 0, "accepted auth socket", 1);
1359 packet_start(SSH2_MSG_CHANNEL_OPEN);
1360 packet_put_cstring("auth-agent@openssh.com");
1361 packet_put_int(nc->self);
1362 packet_put_int(c->local_window_max);
1363 packet_put_int(c->local_maxpacket);
1365 packet_start(SSH_SMSG_AGENT_OPEN);
1366 packet_put_int(nc->self);
1373 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1376 socklen_t sz = sizeof(err);
1378 if (FD_ISSET(c->sock, writeset)) {
1379 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1381 error("getsockopt SO_ERROR failed");
1384 debug("channel %d: connected", c->self);
1385 c->type = SSH_CHANNEL_OPEN;
1387 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1388 packet_put_int(c->remote_id);
1389 packet_put_int(c->self);
1390 packet_put_int(c->local_window);
1391 packet_put_int(c->local_maxpacket);
1393 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1394 packet_put_int(c->remote_id);
1395 packet_put_int(c->self);
1398 debug("channel %d: not connected: %s",
1399 c->self, strerror(err));
1401 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1402 packet_put_int(c->remote_id);
1403 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1404 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1405 packet_put_cstring(strerror(err));
1406 packet_put_cstring("");
1409 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1410 packet_put_int(c->remote_id);
1419 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1421 char buf[CHAN_RBUF];
1425 FD_ISSET(c->rfd, readset)) {
1426 len = read(c->rfd, buf, sizeof(buf));
1427 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1430 debug2("channel %d: read<=0 rfd %d len %d",
1431 c->self, c->rfd, len);
1432 if (c->type != SSH_CHANNEL_OPEN) {
1433 debug2("channel %d: not open", c->self);
1436 } else if (compat13) {
1437 buffer_clear(&c->output);
1438 c->type = SSH_CHANNEL_INPUT_DRAINING;
1439 debug2("channel %d: input draining.", c->self);
1441 chan_read_failed(c);
1445 if (c->input_filter != NULL) {
1446 if (c->input_filter(c, buf, len) == -1) {
1447 debug2("channel %d: filter stops", c->self);
1448 chan_read_failed(c);
1450 } else if (c->datagram) {
1451 buffer_put_string(&c->input, buf, len);
1453 buffer_append(&c->input, buf, len);
1459 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1462 u_char *data = NULL, *buf;
1466 /* Send buffered output data to the socket. */
1468 FD_ISSET(c->wfd, writeset) &&
1469 buffer_len(&c->output) > 0) {
1470 if (c->output_filter != NULL) {
1471 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1472 debug2("channel %d: filter stops", c->self);
1473 if (c->type != SSH_CHANNEL_OPEN)
1476 chan_write_failed(c);
1479 } else if (c->datagram) {
1480 buf = data = buffer_get_string(&c->output, &dlen);
1482 buf = data = buffer_ptr(&c->output);
1483 dlen = buffer_len(&c->output);
1487 /* ignore truncated writes, datagrams might get lost */
1488 c->local_consumed += dlen + 4;
1489 len = write(c->wfd, buf, dlen);
1491 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1494 if (c->type != SSH_CHANNEL_OPEN)
1497 chan_write_failed(c);
1503 /* XXX: Later AIX versions can't push as much data to tty */
1504 if (compat20 && c->wfd_isatty)
1505 dlen = MIN(dlen, 8*1024);
1508 len = write(c->wfd, buf, dlen);
1509 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1512 if (c->type != SSH_CHANNEL_OPEN) {
1513 debug2("channel %d: not open", c->self);
1516 } else if (compat13) {
1517 buffer_clear(&c->output);
1518 debug2("channel %d: input draining.", c->self);
1519 c->type = SSH_CHANNEL_INPUT_DRAINING;
1521 chan_write_failed(c);
1525 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1526 if (tcgetattr(c->wfd, &tio) == 0 &&
1527 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1529 * Simulate echo to reduce the impact of
1530 * traffic analysis. We need to match the
1531 * size of a SSH2_MSG_CHANNEL_DATA message
1532 * (4 byte channel id + buf)
1534 packet_send_ignore(4 + len);
1538 buffer_consume(&c->output, len);
1539 if (compat20 && len > 0) {
1540 c->local_consumed += len;
1546 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1548 char buf[CHAN_RBUF];
1551 /** XXX handle drain efd, too */
1553 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1554 FD_ISSET(c->efd, writeset) &&
1555 buffer_len(&c->extended) > 0) {
1556 len = write(c->efd, buffer_ptr(&c->extended),
1557 buffer_len(&c->extended));
1558 debug2("channel %d: written %d to efd %d",
1559 c->self, len, c->efd);
1560 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1563 debug2("channel %d: closing write-efd %d",
1565 channel_close_fd(&c->efd);
1567 buffer_consume(&c->extended, len);
1568 c->local_consumed += len;
1570 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1571 FD_ISSET(c->efd, readset)) {
1572 len = read(c->efd, buf, sizeof(buf));
1573 debug2("channel %d: read %d from efd %d",
1574 c->self, len, c->efd);
1575 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1578 debug2("channel %d: closing read-efd %d",
1580 channel_close_fd(&c->efd);
1582 buffer_append(&c->extended, buf, len);
1589 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1594 /* Monitor control fd to detect if the slave client exits */
1595 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1596 len = read(c->ctl_fd, buf, sizeof(buf));
1597 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1600 debug2("channel %d: ctl read<=0", c->self);
1601 if (c->type != SSH_CHANNEL_OPEN) {
1602 debug2("channel %d: not open", c->self);
1606 chan_read_failed(c);
1607 chan_write_failed(c);
1611 fatal("%s: unexpected data on ctl fd", __func__);
1616 channel_check_window(Channel *c)
1618 if (c->type == SSH_CHANNEL_OPEN &&
1619 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1620 c->local_window < c->local_window_max/2 &&
1621 c->local_consumed > 0) {
1622 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1623 packet_put_int(c->remote_id);
1624 packet_put_int(c->local_consumed);
1626 debug2("channel %d: window %d sent adjust %d",
1627 c->self, c->local_window,
1629 c->local_window += c->local_consumed;
1630 c->local_consumed = 0;
1636 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1640 channel_handle_rfd(c, readset, writeset);
1641 channel_handle_wfd(c, readset, writeset);
1644 channel_handle_efd(c, readset, writeset);
1645 channel_handle_ctl(c, readset, writeset);
1646 channel_check_window(c);
1650 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1654 /* Send buffered output data to the socket. */
1655 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1656 len = write(c->sock, buffer_ptr(&c->output),
1657 buffer_len(&c->output));
1659 buffer_clear(&c->output);
1661 buffer_consume(&c->output, len);
1666 channel_handler_init_20(void)
1668 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1669 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1670 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1671 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1672 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1673 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1674 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1675 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1677 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1678 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1679 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1680 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1681 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1682 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1683 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1687 channel_handler_init_13(void)
1689 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1690 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1691 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1692 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1693 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1694 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1695 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1696 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1697 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1699 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1700 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1701 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1702 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1703 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1704 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1705 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1709 channel_handler_init_15(void)
1711 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1712 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1713 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1714 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1715 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1716 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1717 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1719 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1720 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1721 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1722 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1723 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1724 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1728 channel_handler_init(void)
1732 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1733 channel_pre[i] = NULL;
1734 channel_post[i] = NULL;
1737 channel_handler_init_20();
1739 channel_handler_init_13();
1741 channel_handler_init_15();
1744 /* gc dead channels */
1746 channel_garbage_collect(Channel *c)
1750 if (c->detach_user != NULL) {
1751 if (!chan_is_dead(c, c->detach_close))
1753 debug2("channel %d: gc: notify user", c->self);
1754 c->detach_user(c->self, NULL);
1755 /* if we still have a callback */
1756 if (c->detach_user != NULL)
1758 debug2("channel %d: gc: user detached", c->self);
1760 if (!chan_is_dead(c, 1))
1762 debug2("channel %d: garbage collecting", c->self);
1767 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1769 static int did_init = 0;
1774 channel_handler_init();
1777 for (i = 0; i < channels_alloc; i++) {
1781 if (ftab[c->type] != NULL)
1782 (*ftab[c->type])(c, readset, writeset);
1783 channel_garbage_collect(c);
1788 * Allocate/update select bitmasks and add any bits relevant to channels in
1792 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1793 u_int *nallocp, int rekeying)
1797 n = MAX(*maxfdp, channel_max_fd);
1799 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1800 /* perhaps check sz < nalloc/2 and shrink? */
1801 if (*readsetp == NULL || sz > *nallocp) {
1802 *readsetp = xrealloc(*readsetp, sz);
1803 *writesetp = xrealloc(*writesetp, sz);
1807 memset(*readsetp, 0, sz);
1808 memset(*writesetp, 0, sz);
1811 channel_handler(channel_pre, *readsetp, *writesetp);
1815 * After select, perform any appropriate operations for channels which have
1819 channel_after_select(fd_set *readset, fd_set *writeset)
1821 channel_handler(channel_post, readset, writeset);
1825 /* If there is data to send to the connection, enqueue some of it now. */
1828 channel_output_poll(void)
1833 for (i = 0; i < channels_alloc; i++) {
1839 * We are only interested in channels that can have buffered
1843 if (c->type != SSH_CHANNEL_OPEN &&
1844 c->type != SSH_CHANNEL_INPUT_DRAINING)
1847 if (c->type != SSH_CHANNEL_OPEN)
1851 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1852 /* XXX is this true? */
1853 debug3("channel %d: will not send data after close", c->self);
1857 /* Get the amount of buffered data for this channel. */
1858 if ((c->istate == CHAN_INPUT_OPEN ||
1859 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1860 (len = buffer_len(&c->input)) > 0) {
1866 data = buffer_get_string(&c->input,
1868 packet_start(SSH2_MSG_CHANNEL_DATA);
1869 packet_put_int(c->remote_id);
1870 packet_put_string(data, dlen);
1872 c->remote_window -= dlen + 4;
1878 * Send some data for the other side over the secure
1882 if (len > c->remote_window)
1883 len = c->remote_window;
1884 if (len > c->remote_maxpacket)
1885 len = c->remote_maxpacket;
1887 if (packet_is_interactive()) {
1891 /* Keep the packets at reasonable size. */
1892 if (len > packet_get_maxsize()/2)
1893 len = packet_get_maxsize()/2;
1897 packet_start(compat20 ?
1898 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1899 packet_put_int(c->remote_id);
1900 packet_put_string(buffer_ptr(&c->input), len);
1902 buffer_consume(&c->input, len);
1903 c->remote_window -= len;
1905 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1907 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1909 * input-buffer is empty and read-socket shutdown:
1910 * tell peer, that we will not send more data: send IEOF.
1911 * hack for extended data: delay EOF if EFD still in use.
1913 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1914 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1915 c->self, c->efd, buffer_len(&c->extended));
1919 /* Send extended data, i.e. stderr */
1921 !(c->flags & CHAN_EOF_SENT) &&
1922 c->remote_window > 0 &&
1923 (len = buffer_len(&c->extended)) > 0 &&
1924 c->extended_usage == CHAN_EXTENDED_READ) {
1925 debug2("channel %d: rwin %u elen %u euse %d",
1926 c->self, c->remote_window, buffer_len(&c->extended),
1928 if (len > c->remote_window)
1929 len = c->remote_window;
1930 if (len > c->remote_maxpacket)
1931 len = c->remote_maxpacket;
1932 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1933 packet_put_int(c->remote_id);
1934 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1935 packet_put_string(buffer_ptr(&c->extended), len);
1937 buffer_consume(&c->extended, len);
1938 c->remote_window -= len;
1939 debug2("channel %d: sent ext data %d", c->self, len);
1945 /* -- protocol input */
1948 channel_input_data(int type, u_int32_t seq, void *ctxt)
1955 /* Get the channel number and verify it. */
1956 id = packet_get_int();
1957 c = channel_lookup(id);
1959 packet_disconnect("Received data for nonexistent channel %d.", id);
1961 /* Ignore any data for non-open channels (might happen on close) */
1962 if (c->type != SSH_CHANNEL_OPEN &&
1963 c->type != SSH_CHANNEL_X11_OPEN)
1967 data = packet_get_string(&data_len);
1970 * Ignore data for protocol > 1.3 if output end is no longer open.
1971 * For protocol 2 the sending side is reducing its window as it sends
1972 * data, so we must 'fake' consumption of the data in order to ensure
1973 * that window updates are sent back. Otherwise the connection might
1976 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1978 c->local_window -= data_len;
1979 c->local_consumed += data_len;
1986 if (data_len > c->local_maxpacket) {
1987 logit("channel %d: rcvd big packet %d, maxpack %d",
1988 c->self, data_len, c->local_maxpacket);
1990 if (data_len > c->local_window) {
1991 logit("channel %d: rcvd too much data %d, win %d",
1992 c->self, data_len, c->local_window);
1996 c->local_window -= data_len;
2000 buffer_put_string(&c->output, data, data_len);
2002 buffer_append(&c->output, data, data_len);
2007 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2011 u_int data_len, tcode;
2014 /* Get the channel number and verify it. */
2015 id = packet_get_int();
2016 c = channel_lookup(id);
2019 packet_disconnect("Received extended_data for bad channel %d.", id);
2020 if (c->type != SSH_CHANNEL_OPEN) {
2021 logit("channel %d: ext data for non open", id);
2024 if (c->flags & CHAN_EOF_RCVD) {
2025 if (datafellows & SSH_BUG_EXTEOF)
2026 debug("channel %d: accepting ext data after eof", id);
2028 packet_disconnect("Received extended_data after EOF "
2029 "on channel %d.", id);
2031 tcode = packet_get_int();
2033 c->extended_usage != CHAN_EXTENDED_WRITE ||
2034 tcode != SSH2_EXTENDED_DATA_STDERR) {
2035 logit("channel %d: bad ext data", c->self);
2038 data = packet_get_string(&data_len);
2040 if (data_len > c->local_window) {
2041 logit("channel %d: rcvd too much extended_data %d, win %d",
2042 c->self, data_len, c->local_window);
2046 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2047 c->local_window -= data_len;
2048 buffer_append(&c->extended, data, data_len);
2053 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2058 id = packet_get_int();
2060 c = channel_lookup(id);
2062 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2065 /* XXX force input close */
2066 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2067 debug("channel %d: FORCE input drain", c->self);
2068 c->istate = CHAN_INPUT_WAIT_DRAIN;
2069 if (buffer_len(&c->input) == 0)
2076 channel_input_close(int type, u_int32_t seq, void *ctxt)
2081 id = packet_get_int();
2083 c = channel_lookup(id);
2085 packet_disconnect("Received close for nonexistent channel %d.", id);
2088 * Send a confirmation that we have closed the channel and no more
2089 * data is coming for it.
2091 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2092 packet_put_int(c->remote_id);
2096 * If the channel is in closed state, we have sent a close request,
2097 * and the other side will eventually respond with a confirmation.
2098 * Thus, we cannot free the channel here, because then there would be
2099 * no-one to receive the confirmation. The channel gets freed when
2100 * the confirmation arrives.
2102 if (c->type != SSH_CHANNEL_CLOSED) {
2104 * Not a closed channel - mark it as draining, which will
2105 * cause it to be freed later.
2107 buffer_clear(&c->input);
2108 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2112 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2114 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2116 int id = packet_get_int();
2117 Channel *c = channel_lookup(id);
2121 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2122 chan_rcvd_oclose(c);
2126 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2128 int id = packet_get_int();
2129 Channel *c = channel_lookup(id);
2133 packet_disconnect("Received close confirmation for "
2134 "out-of-range channel %d.", id);
2135 if (c->type != SSH_CHANNEL_CLOSED)
2136 packet_disconnect("Received close confirmation for "
2137 "non-closed channel %d (type %d).", id, c->type);
2142 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2147 id = packet_get_int();
2148 c = channel_lookup(id);
2150 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2151 packet_disconnect("Received open confirmation for "
2152 "non-opening channel %d.", id);
2153 remote_id = packet_get_int();
2154 /* Record the remote channel number and mark that the channel is now open. */
2155 c->remote_id = remote_id;
2156 c->type = SSH_CHANNEL_OPEN;
2159 c->remote_window = packet_get_int();
2160 c->remote_maxpacket = packet_get_int();
2162 debug2("callback start");
2163 c->confirm(c->self, c->confirm_ctx);
2164 debug2("callback done");
2166 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2167 c->remote_window, c->remote_maxpacket);
2173 reason2txt(int reason)
2176 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2177 return "administratively prohibited";
2178 case SSH2_OPEN_CONNECT_FAILED:
2179 return "connect failed";
2180 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2181 return "unknown channel type";
2182 case SSH2_OPEN_RESOURCE_SHORTAGE:
2183 return "resource shortage";
2185 return "unknown reason";
2189 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2192 char *msg = NULL, *lang = NULL;
2195 id = packet_get_int();
2196 c = channel_lookup(id);
2198 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2199 packet_disconnect("Received open failure for "
2200 "non-opening channel %d.", id);
2202 reason = packet_get_int();
2203 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2204 msg = packet_get_string(NULL);
2205 lang = packet_get_string(NULL);
2207 logit("channel %d: open failed: %s%s%s", id,
2208 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2215 /* Free the channel. This will also close the socket. */
2220 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2229 /* Get the channel number and verify it. */
2230 id = packet_get_int();
2231 c = channel_lookup(id);
2234 logit("Received window adjust for non-open channel %d.", id);
2237 adjust = packet_get_int();
2239 debug2("channel %d: rcvd adjust %u", id, adjust);
2240 c->remote_window += adjust;
2244 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2248 char *host, *originator_string;
2249 int remote_id, sock = -1;
2251 remote_id = packet_get_int();
2252 host = packet_get_string(NULL);
2253 host_port = packet_get_int();
2255 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2256 originator_string = packet_get_string(NULL);
2258 originator_string = xstrdup("unknown (remote did not supply name)");
2261 sock = channel_connect_to(host, host_port);
2263 c = channel_new("connected socket",
2264 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2265 originator_string, 1);
2266 c->remote_id = remote_id;
2268 xfree(originator_string);
2270 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2271 packet_put_int(remote_id);
2278 /* -- tcp forwarding */
2281 channel_set_af(int af)
2287 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2288 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2291 int sock, r, success = 0, wildcard = 0, is_client;
2292 struct addrinfo hints, *ai, *aitop;
2293 const char *host, *addr;
2294 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2296 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2297 listen_addr : host_to_connect;
2298 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2301 error("No forward host name.");
2304 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2305 error("Forward host name too long.");
2310 * Determine whether or not a port forward listens to loopback,
2311 * specified address or wildcard. On the client, a specified bind
2312 * address will always override gateway_ports. On the server, a
2313 * gateway_ports of 1 (``yes'') will override the client's
2314 * specification and force a wildcard bind, whereas a value of 2
2315 * (``clientspecified'') will bind to whatever address the client
2318 * Special-case listen_addrs are:
2320 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2321 * "" (empty string), "*" -> wildcard v4/v6
2322 * "localhost" -> loopback v4/v6
2325 if (listen_addr == NULL) {
2326 /* No address specified: default to gateway_ports setting */
2329 } else if (gateway_ports || is_client) {
2330 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2331 strcmp(listen_addr, "0.0.0.0") == 0) ||
2332 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2333 (!is_client && gateway_ports == 1))
2335 else if (strcmp(listen_addr, "localhost") != 0)
2339 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2340 type, wildcard, (addr == NULL) ? "NULL" : addr);
2343 * getaddrinfo returns a loopback address if the hostname is
2344 * set to NULL and hints.ai_flags is not AI_PASSIVE
2346 memset(&hints, 0, sizeof(hints));
2347 hints.ai_family = IPv4or6;
2348 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2349 hints.ai_socktype = SOCK_STREAM;
2350 snprintf(strport, sizeof strport, "%d", listen_port);
2351 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2353 /* This really shouldn't happen */
2354 packet_disconnect("getaddrinfo: fatal error: %s",
2357 error("channel_setup_fwd_listener: "
2358 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2363 for (ai = aitop; ai; ai = ai->ai_next) {
2364 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2366 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2367 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2368 error("channel_setup_fwd_listener: getnameinfo failed");
2371 /* Create a port to listen for the host. */
2372 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2374 /* this is no error since kernel may not support ipv6 */
2375 verbose("socket: %.100s", strerror(errno));
2379 channel_set_reuseaddr(sock);
2381 debug("Local forwarding listening on %s port %s.", ntop, strport);
2383 /* Bind the socket to the address. */
2384 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2385 /* address can be in use ipv6 address is already bound */
2387 error("bind: %.100s", strerror(errno));
2389 verbose("bind: %.100s", strerror(errno));
2394 /* Start listening for connections on the socket. */
2395 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2396 error("listen: %.100s", strerror(errno));
2400 /* Allocate a channel number for the socket. */
2401 c = channel_new("port listener", type, sock, sock, -1,
2402 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2403 0, "port listener", 1);
2404 strlcpy(c->path, host, sizeof(c->path));
2405 c->host_port = port_to_connect;
2406 c->listening_port = listen_port;
2410 error("channel_setup_fwd_listener: cannot listen to port: %d",
2412 freeaddrinfo(aitop);
2417 channel_cancel_rport_listener(const char *host, u_short port)
2422 for (i = 0; i < channels_alloc; i++) {
2423 Channel *c = channels[i];
2425 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2426 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2427 c->listening_port == port) {
2428 debug2("%s: close channel %d", __func__, i);
2437 /* protocol local port fwd, used by ssh (and sshd in v1) */
2439 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2440 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2442 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2443 listen_host, listen_port, host_to_connect, port_to_connect,
2447 /* protocol v2 remote port fwd, used by sshd */
2449 channel_setup_remote_fwd_listener(const char *listen_address,
2450 u_short listen_port, int gateway_ports)
2452 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2453 listen_address, listen_port, NULL, 0, gateway_ports);
2457 * Initiate forwarding of connections to port "port" on remote host through
2458 * the secure channel to host:port from local side.
2462 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2463 const char *host_to_connect, u_short port_to_connect)
2465 int type, success = 0;
2467 /* Record locally that connection to this host/port is permitted. */
2468 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2469 fatal("channel_request_remote_forwarding: too many forwards");
2471 /* Send the forward request to the remote side. */
2473 const char *address_to_bind;
2474 if (listen_host == NULL)
2475 address_to_bind = "localhost";
2476 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2477 address_to_bind = "";
2479 address_to_bind = listen_host;
2481 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2482 packet_put_cstring("tcpip-forward");
2483 packet_put_char(1); /* boolean: want reply */
2484 packet_put_cstring(address_to_bind);
2485 packet_put_int(listen_port);
2487 packet_write_wait();
2488 /* Assume that server accepts the request */
2491 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2492 packet_put_int(listen_port);
2493 packet_put_cstring(host_to_connect);
2494 packet_put_int(port_to_connect);
2496 packet_write_wait();
2498 /* Wait for response from the remote side. */
2499 type = packet_read();
2501 case SSH_SMSG_SUCCESS:
2504 case SSH_SMSG_FAILURE:
2505 logit("Warning: Server denied remote port forwarding.");
2508 /* Unknown packet */
2509 packet_disconnect("Protocol error for port forward request:"
2510 "received packet type %d.", type);
2514 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2515 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2516 permitted_opens[num_permitted_opens].listen_port = listen_port;
2517 num_permitted_opens++;
2522 * Request cancellation of remote forwarding of connection host:port from
2526 channel_request_rforward_cancel(const char *host, u_short port)
2533 for (i = 0; i < num_permitted_opens; i++) {
2534 if (permitted_opens[i].host_to_connect != NULL &&
2535 permitted_opens[i].listen_port == port)
2538 if (i >= num_permitted_opens) {
2539 debug("%s: requested forward not found", __func__);
2542 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2543 packet_put_cstring("cancel-tcpip-forward");
2545 packet_put_cstring(host == NULL ? "" : host);
2546 packet_put_int(port);
2549 permitted_opens[i].listen_port = 0;
2550 permitted_opens[i].port_to_connect = 0;
2551 xfree(permitted_opens[i].host_to_connect);
2552 permitted_opens[i].host_to_connect = NULL;
2556 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2557 * listening for the port, and sends back a success reply (or disconnect
2558 * message if there was an error). This never returns if there was an error.
2562 channel_input_port_forward_request(int is_root, int gateway_ports)
2564 u_short port, host_port;
2567 /* Get arguments from the packet. */
2568 port = packet_get_int();
2569 hostname = packet_get_string(NULL);
2570 host_port = packet_get_int();
2574 * Check that an unprivileged user is not trying to forward a
2577 if (port < IPPORT_RESERVED && !is_root)
2579 "Requested forwarding of port %d but user is not root.",
2582 packet_disconnect("Dynamic forwarding denied.");
2585 /* Initiate forwarding */
2586 channel_setup_local_fwd_listener(NULL, port, hostname,
2587 host_port, gateway_ports);
2589 /* Free the argument string. */
2594 * Permits opening to any host/port if permitted_opens[] is empty. This is
2595 * usually called by the server, because the user could connect to any port
2596 * anyway, and the server has no way to know but to trust the client anyway.
2599 channel_permit_all_opens(void)
2601 if (num_permitted_opens == 0)
2602 all_opens_permitted = 1;
2606 channel_add_permitted_opens(char *host, int port)
2608 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2609 fatal("channel_request_remote_forwarding: too many forwards");
2610 debug("allow port forwarding to host %s port %d", host, port);
2612 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2613 permitted_opens[num_permitted_opens].port_to_connect = port;
2614 num_permitted_opens++;
2616 all_opens_permitted = 0;
2620 channel_clear_permitted_opens(void)
2624 for (i = 0; i < num_permitted_opens; i++)
2625 if (permitted_opens[i].host_to_connect != NULL)
2626 xfree(permitted_opens[i].host_to_connect);
2627 num_permitted_opens = 0;
2632 /* return socket to remote host, port */
2634 connect_to(const char *host, u_short port)
2636 struct addrinfo hints, *ai, *aitop;
2637 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2641 memset(&hints, 0, sizeof(hints));
2642 hints.ai_family = IPv4or6;
2643 hints.ai_socktype = SOCK_STREAM;
2644 snprintf(strport, sizeof strport, "%d", port);
2645 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2646 error("connect_to %.100s: unknown host (%s)", host,
2647 gai_strerror(gaierr));
2650 for (ai = aitop; ai; ai = ai->ai_next) {
2651 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2653 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2654 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2655 error("connect_to: getnameinfo failed");
2658 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2660 if (ai->ai_next == NULL)
2661 error("socket: %.100s", strerror(errno));
2663 verbose("socket: %.100s", strerror(errno));
2666 if (set_nonblock(sock) == -1)
2667 fatal("%s: set_nonblock(%d)", __func__, sock);
2668 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2669 errno != EINPROGRESS) {
2670 error("connect_to %.100s port %s: %.100s", ntop, strport,
2673 continue; /* fail -- try next */
2675 break; /* success */
2678 freeaddrinfo(aitop);
2680 error("connect_to %.100s port %d: failed.", host, port);
2689 channel_connect_by_listen_address(u_short listen_port)
2693 for (i = 0; i < num_permitted_opens; i++)
2694 if (permitted_opens[i].host_to_connect != NULL &&
2695 permitted_opens[i].listen_port == listen_port)
2697 permitted_opens[i].host_to_connect,
2698 permitted_opens[i].port_to_connect);
2699 error("WARNING: Server requests forwarding for unknown listen_port %d",
2704 /* Check if connecting to that port is permitted and connect. */
2706 channel_connect_to(const char *host, u_short port)
2710 permit = all_opens_permitted;
2712 for (i = 0; i < num_permitted_opens; i++)
2713 if (permitted_opens[i].host_to_connect != NULL &&
2714 permitted_opens[i].port_to_connect == port &&
2715 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2720 logit("Received request to connect to host %.100s port %d, "
2721 "but the request was denied.", host, port);
2724 return connect_to(host, port);
2728 channel_send_window_changes(void)
2733 for (i = 0; i < channels_alloc; i++) {
2734 if (channels[i] == NULL || !channels[i]->client_tty ||
2735 channels[i]->type != SSH_CHANNEL_OPEN)
2737 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2739 channel_request_start(i, "window-change", 0);
2740 packet_put_int((u_int)ws.ws_col);
2741 packet_put_int((u_int)ws.ws_row);
2742 packet_put_int((u_int)ws.ws_xpixel);
2743 packet_put_int((u_int)ws.ws_ypixel);
2748 /* -- X11 forwarding */
2751 * Creates an internet domain socket for listening for X11 connections.
2752 * Returns 0 and a suitable display number for the DISPLAY variable
2753 * stored in display_numberp , or -1 if an error occurs.
2756 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2757 int single_connection, u_int *display_numberp, int **chanids)
2760 int display_number, sock;
2762 struct addrinfo hints, *ai, *aitop;
2763 char strport[NI_MAXSERV];
2764 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2766 if (chanids == NULL)
2769 for (display_number = x11_display_offset;
2770 display_number < MAX_DISPLAYS;
2772 port = 6000 + display_number;
2773 memset(&hints, 0, sizeof(hints));
2774 hints.ai_family = IPv4or6;
2775 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2776 hints.ai_socktype = SOCK_STREAM;
2777 snprintf(strport, sizeof strport, "%d", port);
2778 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2779 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2782 for (ai = aitop; ai; ai = ai->ai_next) {
2783 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2785 sock = socket(ai->ai_family, ai->ai_socktype,
2788 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2789 error("socket: %.100s", strerror(errno));
2790 freeaddrinfo(aitop);
2793 debug("x11_create_display_inet: Socket family %d not supported",
2799 if (ai->ai_family == AF_INET6) {
2801 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2802 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2805 channel_set_reuseaddr(sock);
2806 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2807 debug2("bind port %d: %.100s", port, strerror(errno));
2813 for (n = 0; n < num_socks; n++) {
2819 socks[num_socks++] = sock;
2820 #ifndef DONT_TRY_OTHER_AF
2821 if (num_socks == NUM_SOCKS)
2824 if (x11_use_localhost) {
2825 if (num_socks == NUM_SOCKS)
2832 freeaddrinfo(aitop);
2836 if (display_number >= MAX_DISPLAYS) {
2837 error("Failed to allocate internet-domain X11 display socket.");
2840 /* Start listening for connections on the socket. */
2841 for (n = 0; n < num_socks; n++) {
2843 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2844 error("listen: %.100s", strerror(errno));
2850 /* Allocate a channel for each socket. */
2851 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
2852 for (n = 0; n < num_socks; n++) {
2854 nc = channel_new("x11 listener",
2855 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2856 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2857 0, "X11 inet listener", 1);
2858 nc->single_connection = single_connection;
2859 (*chanids)[n] = nc->self;
2863 /* Return the display number for the DISPLAY environment variable. */
2864 *display_numberp = display_number;
2869 connect_local_xsocket(u_int dnr)
2872 struct sockaddr_un addr;
2874 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2876 error("socket: %.100s", strerror(errno));
2877 memset(&addr, 0, sizeof(addr));
2878 addr.sun_family = AF_UNIX;
2879 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2880 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2883 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2888 x11_connect_display(void)
2890 int display_number, sock = 0;
2891 const char *display;
2892 char buf[1024], *cp;
2893 struct addrinfo hints, *ai, *aitop;
2894 char strport[NI_MAXSERV];
2897 /* Try to open a socket for the local X server. */
2898 display = getenv("DISPLAY");
2900 error("DISPLAY not set.");
2904 * Now we decode the value of the DISPLAY variable and make a
2905 * connection to the real X server.
2909 * Check if it is a unix domain socket. Unix domain displays are in
2910 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2912 if (strncmp(display, "unix:", 5) == 0 ||
2913 display[0] == ':') {
2914 /* Connect to the unix domain socket. */
2915 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2916 error("Could not parse display number from DISPLAY: %.100s",
2920 /* Create a socket. */
2921 sock = connect_local_xsocket(display_number);
2925 /* OK, we now have a connection to the display. */
2929 * Connect to an inet socket. The DISPLAY value is supposedly
2930 * hostname:d[.s], where hostname may also be numeric IP address.
2932 strlcpy(buf, display, sizeof(buf));
2933 cp = strchr(buf, ':');
2935 error("Could not find ':' in DISPLAY: %.100s", display);
2939 /* buf now contains the host name. But first we parse the display number. */
2940 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2941 error("Could not parse display number from DISPLAY: %.100s",
2946 /* Look up the host address */
2947 memset(&hints, 0, sizeof(hints));
2948 hints.ai_family = IPv4or6;
2949 hints.ai_socktype = SOCK_STREAM;
2950 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2951 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2952 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2955 for (ai = aitop; ai; ai = ai->ai_next) {
2956 /* Create a socket. */
2957 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2959 debug2("socket: %.100s", strerror(errno));
2962 /* Connect it to the display. */
2963 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2964 debug2("connect %.100s port %d: %.100s", buf,
2965 6000 + display_number, strerror(errno));
2972 freeaddrinfo(aitop);
2974 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2983 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2984 * the remote channel number. We should do whatever we want, and respond
2985 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2989 x11_input_open(int type, u_int32_t seq, void *ctxt)
2992 int remote_id, sock = 0;
2995 debug("Received X11 open request.");
2997 remote_id = packet_get_int();
2999 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3000 remote_host = packet_get_string(NULL);
3002 remote_host = xstrdup("unknown (remote did not supply name)");
3006 /* Obtain a connection to the real X display. */
3007 sock = x11_connect_display();
3009 /* Allocate a channel for this connection. */
3010 c = channel_new("connected x11 socket",
3011 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3013 c->remote_id = remote_id;
3018 /* Send refusal to the remote host. */
3019 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3020 packet_put_int(remote_id);
3022 /* Send a confirmation to the remote host. */
3023 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3024 packet_put_int(remote_id);
3025 packet_put_int(c->self);
3030 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3032 deny_input_open(int type, u_int32_t seq, void *ctxt)
3034 int rchan = packet_get_int();
3037 case SSH_SMSG_AGENT_OPEN:
3038 error("Warning: ssh server tried agent forwarding.");
3040 case SSH_SMSG_X11_OPEN:
3041 error("Warning: ssh server tried X11 forwarding.");
3044 error("deny_input_open: type %d", type);
3047 error("Warning: this is probably a break-in attempt by a malicious server.");
3048 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3049 packet_put_int(rchan);
3054 * Requests forwarding of X11 connections, generates fake authentication
3055 * data, and enables authentication spoofing.
3056 * This should be called in the client only.
3059 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3060 const char *proto, const char *data)
3062 u_int data_len = (u_int) strlen(data) / 2;
3069 if (x11_saved_display == NULL)
3070 x11_saved_display = xstrdup(disp);
3071 else if (strcmp(disp, x11_saved_display) != 0) {
3072 error("x11_request_forwarding_with_spoofing: different "
3073 "$DISPLAY already forwarded");
3079 cp = strchr(disp, ':');
3081 cp = strchr(cp, '.');
3083 screen_number = atoi(cp + 1);
3087 if (x11_saved_proto == NULL) {
3088 /* Save protocol name. */
3089 x11_saved_proto = xstrdup(proto);
3091 * Extract real authentication data and generate fake data
3092 * of the same length.
3094 x11_saved_data = xmalloc(data_len);
3095 x11_fake_data = xmalloc(data_len);
3096 for (i = 0; i < data_len; i++) {
3097 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3098 fatal("x11_request_forwarding: bad "
3099 "authentication data: %.100s", data);
3102 x11_saved_data[i] = value;
3103 x11_fake_data[i] = rnd & 0xff;
3106 x11_saved_data_len = data_len;
3107 x11_fake_data_len = data_len;
3110 /* Convert the fake data into hex. */
3111 new_data = tohex(x11_fake_data, data_len);
3113 /* Send the request packet. */
3115 channel_request_start(client_session_id, "x11-req", 0);
3116 packet_put_char(0); /* XXX bool single connection */
3118 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3120 packet_put_cstring(proto);
3121 packet_put_cstring(new_data);
3122 packet_put_int(screen_number);
3124 packet_write_wait();
3129 /* -- agent forwarding */
3131 /* Sends a message to the server to request authentication fd forwarding. */
3134 auth_request_forwarding(void)
3136 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3138 packet_write_wait();