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 u_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
196 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
197 int extusage, int nonblock)
199 /* Update the maximum file descriptor value. */
200 channel_max_fd = MAX(channel_max_fd, rfd);
201 channel_max_fd = MAX(channel_max_fd, wfd);
202 channel_max_fd = MAX(channel_max_fd, efd);
204 /* XXX set close-on-exec -markus */
208 c->sock = (rfd == wfd) ? rfd : -1;
209 c->ctl_fd = -1; /* XXX: set elsewhere */
211 c->extended_usage = extusage;
213 /* XXX ugly hack: nonblock is only set by the server */
214 if (nonblock && isatty(c->rfd)) {
215 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
217 if (!isatty(c->wfd)) {
218 error("channel %d: wfd %d is not a tty?",
224 c->wfd_isatty = isatty(c->wfd);
226 /* enable nonblocking mode */
238 * Allocate a new channel object and set its type and socket. This will cause
239 * remote_name to be freed.
242 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
243 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
249 /* Do initial allocation if this is the first call. */
250 if (channels_alloc == 0) {
252 channels = xmalloc(channels_alloc * sizeof(Channel *));
253 for (i = 0; i < channels_alloc; i++)
256 /* Try to find a free slot where to put the new channel. */
257 for (found = -1, i = 0; i < channels_alloc; i++)
258 if (channels[i] == NULL) {
259 /* Found a free slot. */
264 /* There are no free slots. Take last+1 slot and expand the array. */
265 found = channels_alloc;
266 if (channels_alloc > 10000)
267 fatal("channel_new: internal error: channels_alloc %d "
268 "too big.", channels_alloc);
269 channels = xrealloc(channels,
270 (channels_alloc + 10) * sizeof(Channel *));
271 channels_alloc += 10;
272 debug2("channel: expanding %d", channels_alloc);
273 for (i = found; i < channels_alloc; i++)
276 /* Initialize and return new channel. */
277 c = channels[found] = xmalloc(sizeof(Channel));
278 memset(c, 0, sizeof(Channel));
279 buffer_init(&c->input);
280 buffer_init(&c->output);
281 buffer_init(&c->extended);
282 c->ostate = CHAN_OUTPUT_OPEN;
283 c->istate = CHAN_INPUT_OPEN;
285 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
289 c->local_window = window;
290 c->local_window_max = window;
291 c->local_consumed = 0;
292 c->local_maxpacket = maxpack;
294 c->remote_name = xstrdup(remote_name);
295 c->remote_window = 0;
296 c->remote_maxpacket = 0;
298 c->single_connection = 0;
299 c->detach_user = NULL;
302 c->confirm_ctx = NULL;
303 c->input_filter = NULL;
304 c->output_filter = NULL;
305 debug("channel %d: new [%s]", found, remote_name);
310 channel_find_maxfd(void)
316 for (i = 0; i < channels_alloc; i++) {
319 max = MAX(max, c->rfd);
320 max = MAX(max, c->wfd);
321 max = MAX(max, c->efd);
328 channel_close_fd(int *fdp)
330 int ret = 0, fd = *fdp;
335 if (fd == channel_max_fd)
336 channel_max_fd = channel_find_maxfd();
341 /* Close all channel fd/socket. */
343 channel_close_fds(Channel *c)
345 debug3("channel %d: close_fds r %d w %d e %d c %d",
346 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
348 channel_close_fd(&c->sock);
349 channel_close_fd(&c->ctl_fd);
350 channel_close_fd(&c->rfd);
351 channel_close_fd(&c->wfd);
352 channel_close_fd(&c->efd);
355 /* Free the channel and close its fd/socket. */
357 channel_free(Channel *c)
362 for (n = 0, i = 0; i < channels_alloc; i++)
365 debug("channel %d: free: %s, nchannels %u", c->self,
366 c->remote_name ? c->remote_name : "???", n);
368 s = channel_open_message();
369 debug3("channel %d: status: %s", c->self, s);
373 shutdown(c->sock, SHUT_RDWR);
375 shutdown(c->ctl_fd, SHUT_RDWR);
376 channel_close_fds(c);
377 buffer_free(&c->input);
378 buffer_free(&c->output);
379 buffer_free(&c->extended);
380 if (c->remote_name) {
381 xfree(c->remote_name);
382 c->remote_name = NULL;
384 channels[c->self] = NULL;
389 channel_free_all(void)
393 for (i = 0; i < channels_alloc; i++)
394 if (channels[i] != NULL)
395 channel_free(channels[i]);
399 * Closes the sockets/fds of all channels. This is used to close extra file
400 * descriptors after a fork.
403 channel_close_all(void)
407 for (i = 0; i < channels_alloc; i++)
408 if (channels[i] != NULL)
409 channel_close_fds(channels[i]);
413 * Stop listening to channels.
416 channel_stop_listening(void)
421 for (i = 0; i < channels_alloc; i++) {
425 case SSH_CHANNEL_AUTH_SOCKET:
426 case SSH_CHANNEL_PORT_LISTENER:
427 case SSH_CHANNEL_RPORT_LISTENER:
428 case SSH_CHANNEL_X11_LISTENER:
429 channel_close_fd(&c->sock);
438 * Returns true if no channel has too much buffered data, and false if one or
439 * more channel is overfull.
442 channel_not_very_much_buffered_data(void)
447 for (i = 0; i < channels_alloc; i++) {
449 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
452 buffer_len(&c->input) > packet_get_maxsize()) {
453 debug2("channel %d: big input buffer %d",
454 c->self, buffer_len(&c->input));
458 if (buffer_len(&c->output) > packet_get_maxsize()) {
459 debug2("channel %d: big output buffer %u > %u",
460 c->self, buffer_len(&c->output),
461 packet_get_maxsize());
469 /* Returns true if any channel is still open. */
471 channel_still_open(void)
476 for (i = 0; i < channels_alloc; i++) {
481 case SSH_CHANNEL_X11_LISTENER:
482 case SSH_CHANNEL_PORT_LISTENER:
483 case SSH_CHANNEL_RPORT_LISTENER:
484 case SSH_CHANNEL_CLOSED:
485 case SSH_CHANNEL_AUTH_SOCKET:
486 case SSH_CHANNEL_DYNAMIC:
487 case SSH_CHANNEL_CONNECTING:
488 case SSH_CHANNEL_ZOMBIE:
490 case SSH_CHANNEL_LARVAL:
492 fatal("cannot happen: SSH_CHANNEL_LARVAL");
494 case SSH_CHANNEL_OPENING:
495 case SSH_CHANNEL_OPEN:
496 case SSH_CHANNEL_X11_OPEN:
498 case SSH_CHANNEL_INPUT_DRAINING:
499 case SSH_CHANNEL_OUTPUT_DRAINING:
501 fatal("cannot happen: OUT_DRAIN");
504 fatal("channel_still_open: bad channel type %d", c->type);
511 /* Returns the id of an open channel suitable for keepaliving */
513 channel_find_open(void)
518 for (i = 0; i < channels_alloc; i++) {
520 if (c == NULL || c->remote_id < 0)
523 case SSH_CHANNEL_CLOSED:
524 case SSH_CHANNEL_DYNAMIC:
525 case SSH_CHANNEL_X11_LISTENER:
526 case SSH_CHANNEL_PORT_LISTENER:
527 case SSH_CHANNEL_RPORT_LISTENER:
528 case SSH_CHANNEL_OPENING:
529 case SSH_CHANNEL_CONNECTING:
530 case SSH_CHANNEL_ZOMBIE:
532 case SSH_CHANNEL_LARVAL:
533 case SSH_CHANNEL_AUTH_SOCKET:
534 case SSH_CHANNEL_OPEN:
535 case SSH_CHANNEL_X11_OPEN:
537 case SSH_CHANNEL_INPUT_DRAINING:
538 case SSH_CHANNEL_OUTPUT_DRAINING:
540 fatal("cannot happen: OUT_DRAIN");
543 fatal("channel_find_open: bad channel type %d", c->type);
552 * Returns a message describing the currently open forwarded connections,
553 * suitable for sending to the client. The message contains crlf pairs for
557 channel_open_message(void)
564 buffer_init(&buffer);
565 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
566 buffer_append(&buffer, buf, strlen(buf));
567 for (i = 0; i < channels_alloc; i++) {
572 case SSH_CHANNEL_X11_LISTENER:
573 case SSH_CHANNEL_PORT_LISTENER:
574 case SSH_CHANNEL_RPORT_LISTENER:
575 case SSH_CHANNEL_CLOSED:
576 case SSH_CHANNEL_AUTH_SOCKET:
577 case SSH_CHANNEL_ZOMBIE:
579 case SSH_CHANNEL_LARVAL:
580 case SSH_CHANNEL_OPENING:
581 case SSH_CHANNEL_CONNECTING:
582 case SSH_CHANNEL_DYNAMIC:
583 case SSH_CHANNEL_OPEN:
584 case SSH_CHANNEL_X11_OPEN:
585 case SSH_CHANNEL_INPUT_DRAINING:
586 case SSH_CHANNEL_OUTPUT_DRAINING:
587 snprintf(buf, sizeof buf,
588 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
589 c->self, c->remote_name,
590 c->type, c->remote_id,
591 c->istate, buffer_len(&c->input),
592 c->ostate, buffer_len(&c->output),
593 c->rfd, c->wfd, c->ctl_fd);
594 buffer_append(&buffer, buf, strlen(buf));
597 fatal("channel_open_message: bad channel type %d", c->type);
601 buffer_append(&buffer, "\0", 1);
602 cp = xstrdup(buffer_ptr(&buffer));
603 buffer_free(&buffer);
608 channel_send_open(int id)
610 Channel *c = channel_lookup(id);
613 logit("channel_send_open: %d: bad id", id);
616 debug2("channel %d: send open", id);
617 packet_start(SSH2_MSG_CHANNEL_OPEN);
618 packet_put_cstring(c->ctype);
619 packet_put_int(c->self);
620 packet_put_int(c->local_window);
621 packet_put_int(c->local_maxpacket);
626 channel_request_start(int id, char *service, int wantconfirm)
628 Channel *c = channel_lookup(id);
631 logit("channel_request_start: %d: unknown channel id", id);
634 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
635 packet_start(SSH2_MSG_CHANNEL_REQUEST);
636 packet_put_int(c->remote_id);
637 packet_put_cstring(service);
638 packet_put_char(wantconfirm);
642 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
644 Channel *c = channel_lookup(id);
647 logit("channel_register_comfirm: %d: bad id", id);
651 c->confirm_ctx = ctx;
655 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
657 Channel *c = channel_by_id(id);
660 logit("channel_register_cleanup: %d: bad id", id);
664 c->detach_close = do_close;
668 channel_cancel_cleanup(int id)
670 Channel *c = channel_by_id(id);
673 logit("channel_cancel_cleanup: %d: bad id", id);
676 c->detach_user = NULL;
681 channel_register_filter(int id, channel_infilter_fn *ifn,
682 channel_outfilter_fn *ofn)
684 Channel *c = channel_lookup(id);
687 logit("channel_register_filter: %d: bad id", id);
690 c->input_filter = ifn;
691 c->output_filter = ofn;
695 channel_set_fds(int id, int rfd, int wfd, int efd,
696 int extusage, int nonblock, u_int window_max)
698 Channel *c = channel_lookup(id);
700 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
701 fatal("channel_activate for non-larval channel %d.", id);
702 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
703 c->type = SSH_CHANNEL_OPEN;
704 c->local_window = c->local_window_max = window_max;
705 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
706 packet_put_int(c->remote_id);
707 packet_put_int(c->local_window);
712 * 'channel_pre*' are called just before select() to add any bits relevant to
713 * channels in the select bitmasks.
716 * 'channel_post*': perform any appropriate operations for channels which
717 * have events pending.
719 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
720 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
721 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
724 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
726 FD_SET(c->sock, readset);
730 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
732 debug3("channel %d: waiting for connection", c->self);
733 FD_SET(c->sock, writeset);
737 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
739 if (buffer_len(&c->input) < packet_get_maxsize())
740 FD_SET(c->sock, readset);
741 if (buffer_len(&c->output) > 0)
742 FD_SET(c->sock, writeset);
746 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
748 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
750 /* check buffer limits */
751 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
753 if (c->istate == CHAN_INPUT_OPEN &&
755 buffer_len(&c->input) < limit)
756 FD_SET(c->rfd, readset);
757 if (c->ostate == CHAN_OUTPUT_OPEN ||
758 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
759 if (buffer_len(&c->output) > 0) {
760 FD_SET(c->wfd, writeset);
761 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
762 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
763 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
764 c->self, c->efd, buffer_len(&c->extended));
769 /** XXX check close conditions, too */
770 if (compat20 && c->efd != -1) {
771 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
772 buffer_len(&c->extended) > 0)
773 FD_SET(c->efd, writeset);
774 else if (!(c->flags & CHAN_EOF_SENT) &&
775 c->extended_usage == CHAN_EXTENDED_READ &&
776 buffer_len(&c->extended) < c->remote_window)
777 FD_SET(c->efd, readset);
779 /* XXX: What about efd? races? */
780 if (compat20 && c->ctl_fd != -1 &&
781 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
782 FD_SET(c->ctl_fd, readset);
786 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
788 if (buffer_len(&c->input) == 0) {
789 packet_start(SSH_MSG_CHANNEL_CLOSE);
790 packet_put_int(c->remote_id);
792 c->type = SSH_CHANNEL_CLOSED;
793 debug2("channel %d: closing after input drain.", c->self);
798 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
800 if (buffer_len(&c->output) == 0)
803 FD_SET(c->sock, writeset);
807 * This is a special state for X11 authentication spoofing. An opened X11
808 * connection (when authentication spoofing is being done) remains in this
809 * state until the first packet has been completely read. The authentication
810 * data in that packet is then substituted by the real data if it matches the
811 * fake data, and the channel is put into normal mode.
812 * XXX All this happens at the client side.
813 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
816 x11_open_helper(Buffer *b)
819 u_int proto_len, data_len;
821 /* Check if the fixed size part of the packet is in buffer. */
822 if (buffer_len(b) < 12)
825 /* Parse the lengths of variable-length fields. */
827 if (ucp[0] == 0x42) { /* Byte order MSB first. */
828 proto_len = 256 * ucp[6] + ucp[7];
829 data_len = 256 * ucp[8] + ucp[9];
830 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
831 proto_len = ucp[6] + 256 * ucp[7];
832 data_len = ucp[8] + 256 * ucp[9];
834 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
839 /* Check if the whole packet is in buffer. */
841 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
844 /* Check if authentication protocol matches. */
845 if (proto_len != strlen(x11_saved_proto) ||
846 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
847 debug2("X11 connection uses different authentication protocol.");
850 /* Check if authentication data matches our fake data. */
851 if (data_len != x11_fake_data_len ||
852 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
853 x11_fake_data, x11_fake_data_len) != 0) {
854 debug2("X11 auth data does not match fake data.");
857 /* Check fake data length */
858 if (x11_fake_data_len != x11_saved_data_len) {
859 error("X11 fake_data_len %d != saved_data_len %d",
860 x11_fake_data_len, x11_saved_data_len);
864 * Received authentication protocol and data match
865 * our fake data. Substitute the fake data with real
868 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
869 x11_saved_data, x11_saved_data_len);
874 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
876 int ret = x11_open_helper(&c->output);
879 /* Start normal processing for the channel. */
880 c->type = SSH_CHANNEL_OPEN;
881 channel_pre_open_13(c, readset, writeset);
882 } else if (ret == -1) {
884 * We have received an X11 connection that has bad
885 * authentication information.
887 logit("X11 connection rejected because of wrong authentication.");
888 buffer_clear(&c->input);
889 buffer_clear(&c->output);
890 channel_close_fd(&c->sock);
892 c->type = SSH_CHANNEL_CLOSED;
893 packet_start(SSH_MSG_CHANNEL_CLOSE);
894 packet_put_int(c->remote_id);
900 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
902 int ret = x11_open_helper(&c->output);
904 /* c->force_drain = 1; */
907 c->type = SSH_CHANNEL_OPEN;
908 channel_pre_open(c, readset, writeset);
909 } else if (ret == -1) {
910 logit("X11 connection rejected because of wrong authentication.");
911 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
913 buffer_clear(&c->input);
915 buffer_clear(&c->output);
916 /* for proto v1, the peer will send an IEOF */
918 chan_write_failed(c);
920 c->type = SSH_CHANNEL_OPEN;
921 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
925 /* try to decode a socks4 header */
927 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
930 u_int len, have, i, found;
936 struct in_addr dest_addr;
939 debug2("channel %d: decode socks4", c->self);
941 have = buffer_len(&c->input);
942 len = sizeof(s4_req);
945 p = buffer_ptr(&c->input);
946 for (found = 0, i = len; i < have; i++) {
952 /* the peer is probably sending garbage */
953 debug("channel %d: decode socks4: too long",
960 buffer_get(&c->input, (char *)&s4_req.version, 1);
961 buffer_get(&c->input, (char *)&s4_req.command, 1);
962 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
963 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
964 have = buffer_len(&c->input);
965 p = buffer_ptr(&c->input);
967 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
969 fatal("channel %d: decode socks4: len %d > have %d",
971 strlcpy(username, p, sizeof(username));
972 buffer_consume(&c->input, len);
973 buffer_consume(&c->input, 1); /* trailing '\0' */
975 host = inet_ntoa(s4_req.dest_addr);
976 strlcpy(c->path, host, sizeof(c->path));
977 c->host_port = ntohs(s4_req.dest_port);
979 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
980 c->self, host, c->host_port, s4_req.command);
982 if (s4_req.command != 1) {
983 debug("channel %d: cannot handle: socks4 cn %d",
984 c->self, s4_req.command);
987 s4_rsp.version = 0; /* vn: 0 for reply */
988 s4_rsp.command = 90; /* cd: req granted */
989 s4_rsp.dest_port = 0; /* ignored */
990 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
991 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
995 /* try to decode a socks5 header */
996 #define SSH_SOCKS5_AUTHDONE 0x1000
997 #define SSH_SOCKS5_NOAUTH 0x00
998 #define SSH_SOCKS5_IPV4 0x01
999 #define SSH_SOCKS5_DOMAIN 0x03
1000 #define SSH_SOCKS5_IPV6 0x04
1001 #define SSH_SOCKS5_CONNECT 0x01
1002 #define SSH_SOCKS5_SUCCESS 0x00
1005 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1013 u_int16_t dest_port;
1014 u_char *p, dest_addr[255+1];
1015 u_int have, i, found, nmethods, addrlen, af;
1017 debug2("channel %d: decode socks5", c->self);
1018 p = buffer_ptr(&c->input);
1021 have = buffer_len(&c->input);
1022 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1023 /* format: ver | nmethods | methods */
1027 if (have < nmethods + 2)
1029 /* look for method: "NO AUTHENTICATION REQUIRED" */
1030 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1031 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1037 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1041 buffer_consume(&c->input, nmethods + 2);
1042 buffer_put_char(&c->output, 0x05); /* version */
1043 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1044 FD_SET(c->sock, writeset);
1045 c->flags |= SSH_SOCKS5_AUTHDONE;
1046 debug2("channel %d: socks5 auth done", c->self);
1047 return 0; /* need more */
1049 debug2("channel %d: socks5 post auth", c->self);
1050 if (have < sizeof(s5_req)+1)
1051 return 0; /* need more */
1052 memcpy((char *)&s5_req, p, sizeof(s5_req));
1053 if (s5_req.version != 0x05 ||
1054 s5_req.command != SSH_SOCKS5_CONNECT ||
1055 s5_req.reserved != 0x00) {
1056 debug2("channel %d: only socks5 connect supported", c->self);
1059 switch (s5_req.atyp){
1060 case SSH_SOCKS5_IPV4:
1064 case SSH_SOCKS5_DOMAIN:
1065 addrlen = p[sizeof(s5_req)];
1068 case SSH_SOCKS5_IPV6:
1073 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1076 if (have < 4 + addrlen + 2)
1078 buffer_consume(&c->input, sizeof(s5_req));
1079 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1080 buffer_consume(&c->input, 1); /* host string length */
1081 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1082 buffer_get(&c->input, (char *)&dest_port, 2);
1083 dest_addr[addrlen] = '\0';
1084 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1085 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1086 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1088 c->host_port = ntohs(dest_port);
1090 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1091 c->self, c->path, c->host_port, s5_req.command);
1093 s5_rsp.version = 0x05;
1094 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1095 s5_rsp.reserved = 0; /* ignored */
1096 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1097 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1098 dest_port = 0; /* ignored */
1100 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1101 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1102 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1106 /* dynamic port forwarding */
1108 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1114 have = buffer_len(&c->input);
1116 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1117 /* buffer_dump(&c->input); */
1118 /* check if the fixed size part of the packet is in buffer. */
1121 FD_SET(c->sock, readset);
1124 /* try to guess the protocol */
1125 p = buffer_ptr(&c->input);
1128 ret = channel_decode_socks4(c, readset, writeset);
1131 ret = channel_decode_socks5(c, readset, writeset);
1139 } else if (ret == 0) {
1140 debug2("channel %d: pre_dynamic: need more", c->self);
1142 FD_SET(c->sock, readset);
1144 /* switch to the next state */
1145 c->type = SSH_CHANNEL_OPENING;
1146 port_open_helper(c, "direct-tcpip");
1150 /* This is our fake X11 server socket. */
1152 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1155 struct sockaddr addr;
1158 char buf[16384], *remote_ipaddr;
1161 if (FD_ISSET(c->sock, readset)) {
1162 debug("X11 connection requested.");
1163 addrlen = sizeof(addr);
1164 newsock = accept(c->sock, &addr, &addrlen);
1165 if (c->single_connection) {
1166 debug2("single_connection: closing X11 listener.");
1167 channel_close_fd(&c->sock);
1171 error("accept: %.100s", strerror(errno));
1174 set_nodelay(newsock);
1175 remote_ipaddr = get_peer_ipaddr(newsock);
1176 remote_port = get_peer_port(newsock);
1177 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1178 remote_ipaddr, remote_port);
1180 nc = channel_new("accepted x11 socket",
1181 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1182 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1184 packet_start(SSH2_MSG_CHANNEL_OPEN);
1185 packet_put_cstring("x11");
1186 packet_put_int(nc->self);
1187 packet_put_int(nc->local_window_max);
1188 packet_put_int(nc->local_maxpacket);
1189 /* originator ipaddr and port */
1190 packet_put_cstring(remote_ipaddr);
1191 if (datafellows & SSH_BUG_X11FWD) {
1192 debug2("ssh2 x11 bug compat mode");
1194 packet_put_int(remote_port);
1198 packet_start(SSH_SMSG_X11_OPEN);
1199 packet_put_int(nc->self);
1200 if (packet_get_protocol_flags() &
1201 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1202 packet_put_cstring(buf);
1205 xfree(remote_ipaddr);
1210 port_open_helper(Channel *c, char *rtype)
1214 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1215 int remote_port = get_peer_port(c->sock);
1217 direct = (strcmp(rtype, "direct-tcpip") == 0);
1219 snprintf(buf, sizeof buf,
1220 "%s: listening port %d for %.100s port %d, "
1221 "connect from %.200s port %d",
1222 rtype, c->listening_port, c->path, c->host_port,
1223 remote_ipaddr, remote_port);
1225 xfree(c->remote_name);
1226 c->remote_name = xstrdup(buf);
1229 packet_start(SSH2_MSG_CHANNEL_OPEN);
1230 packet_put_cstring(rtype);
1231 packet_put_int(c->self);
1232 packet_put_int(c->local_window_max);
1233 packet_put_int(c->local_maxpacket);
1235 /* target host, port */
1236 packet_put_cstring(c->path);
1237 packet_put_int(c->host_port);
1239 /* listen address, port */
1240 packet_put_cstring(c->path);
1241 packet_put_int(c->listening_port);
1243 /* originator host and port */
1244 packet_put_cstring(remote_ipaddr);
1245 packet_put_int((u_int)remote_port);
1248 packet_start(SSH_MSG_PORT_OPEN);
1249 packet_put_int(c->self);
1250 packet_put_cstring(c->path);
1251 packet_put_int(c->host_port);
1252 if (packet_get_protocol_flags() &
1253 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1254 packet_put_cstring(c->remote_name);
1257 xfree(remote_ipaddr);
1261 channel_set_reuseaddr(int fd)
1266 * Set socket options.
1267 * Allow local port reuse in TIME_WAIT.
1269 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1270 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1274 * This socket is listening for connections to a forwarded TCP/IP port.
1277 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1280 struct sockaddr addr;
1281 int newsock, nextstate;
1285 if (FD_ISSET(c->sock, readset)) {
1286 debug("Connection to port %d forwarding "
1287 "to %.100s port %d requested.",
1288 c->listening_port, c->path, c->host_port);
1290 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1291 nextstate = SSH_CHANNEL_OPENING;
1292 rtype = "forwarded-tcpip";
1294 if (c->host_port == 0) {
1295 nextstate = SSH_CHANNEL_DYNAMIC;
1296 rtype = "dynamic-tcpip";
1298 nextstate = SSH_CHANNEL_OPENING;
1299 rtype = "direct-tcpip";
1303 addrlen = sizeof(addr);
1304 newsock = accept(c->sock, &addr, &addrlen);
1306 error("accept: %.100s", strerror(errno));
1309 set_nodelay(newsock);
1310 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1311 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1312 nc->listening_port = c->listening_port;
1313 nc->host_port = c->host_port;
1314 strlcpy(nc->path, c->path, sizeof(nc->path));
1316 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1318 * do not call the channel_post handler until
1319 * this flag has been reset by a pre-handler.
1320 * otherwise the FD_ISSET calls might overflow
1324 port_open_helper(nc, rtype);
1330 * This is the authentication agent socket listening for connections from
1334 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1338 struct sockaddr addr;
1341 if (FD_ISSET(c->sock, readset)) {
1342 addrlen = sizeof(addr);
1343 newsock = accept(c->sock, &addr, &addrlen);
1345 error("accept from auth socket: %.100s", strerror(errno));
1348 nc = channel_new("accepted auth socket",
1349 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1350 c->local_window_max, c->local_maxpacket,
1351 0, "accepted auth socket", 1);
1353 packet_start(SSH2_MSG_CHANNEL_OPEN);
1354 packet_put_cstring("auth-agent@openssh.com");
1355 packet_put_int(nc->self);
1356 packet_put_int(c->local_window_max);
1357 packet_put_int(c->local_maxpacket);
1359 packet_start(SSH_SMSG_AGENT_OPEN);
1360 packet_put_int(nc->self);
1367 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1370 socklen_t sz = sizeof(err);
1372 if (FD_ISSET(c->sock, writeset)) {
1373 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1375 error("getsockopt SO_ERROR failed");
1378 debug("channel %d: connected", c->self);
1379 c->type = SSH_CHANNEL_OPEN;
1381 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1382 packet_put_int(c->remote_id);
1383 packet_put_int(c->self);
1384 packet_put_int(c->local_window);
1385 packet_put_int(c->local_maxpacket);
1387 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1388 packet_put_int(c->remote_id);
1389 packet_put_int(c->self);
1392 debug("channel %d: not connected: %s",
1393 c->self, strerror(err));
1395 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1396 packet_put_int(c->remote_id);
1397 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1398 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1399 packet_put_cstring(strerror(err));
1400 packet_put_cstring("");
1403 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1404 packet_put_int(c->remote_id);
1413 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1415 char buf[CHAN_RBUF];
1419 FD_ISSET(c->rfd, readset)) {
1420 len = read(c->rfd, buf, sizeof(buf));
1421 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1424 debug2("channel %d: read<=0 rfd %d len %d",
1425 c->self, c->rfd, len);
1426 if (c->type != SSH_CHANNEL_OPEN) {
1427 debug2("channel %d: not open", c->self);
1430 } else if (compat13) {
1431 buffer_clear(&c->output);
1432 c->type = SSH_CHANNEL_INPUT_DRAINING;
1433 debug2("channel %d: input draining.", c->self);
1435 chan_read_failed(c);
1439 if (c->input_filter != NULL) {
1440 if (c->input_filter(c, buf, len) == -1) {
1441 debug2("channel %d: filter stops", c->self);
1442 chan_read_failed(c);
1444 } else if (c->datagram) {
1445 buffer_put_string(&c->input, buf, len);
1447 buffer_append(&c->input, buf, len);
1454 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1457 u_char *data = NULL, *buf;
1461 /* Send buffered output data to the socket. */
1463 FD_ISSET(c->wfd, writeset) &&
1464 buffer_len(&c->output) > 0) {
1465 if (c->output_filter != NULL) {
1466 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1467 debug2("channel %d: filter stops", c->self);
1468 if (c->type != SSH_CHANNEL_OPEN)
1471 chan_write_failed(c);
1474 } else if (c->datagram) {
1475 buf = data = buffer_get_string(&c->output, &dlen);
1477 buf = data = buffer_ptr(&c->output);
1478 dlen = buffer_len(&c->output);
1482 /* ignore truncated writes, datagrams might get lost */
1483 c->local_consumed += dlen + 4;
1484 len = write(c->wfd, buf, dlen);
1486 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1489 if (c->type != SSH_CHANNEL_OPEN)
1492 chan_write_failed(c);
1498 /* XXX: Later AIX versions can't push as much data to tty */
1499 if (compat20 && c->wfd_isatty)
1500 dlen = MIN(dlen, 8*1024);
1503 len = write(c->wfd, buf, dlen);
1504 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1507 if (c->type != SSH_CHANNEL_OPEN) {
1508 debug2("channel %d: not open", c->self);
1511 } else if (compat13) {
1512 buffer_clear(&c->output);
1513 debug2("channel %d: input draining.", c->self);
1514 c->type = SSH_CHANNEL_INPUT_DRAINING;
1516 chan_write_failed(c);
1520 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1521 if (tcgetattr(c->wfd, &tio) == 0 &&
1522 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1524 * Simulate echo to reduce the impact of
1525 * traffic analysis. We need to match the
1526 * size of a SSH2_MSG_CHANNEL_DATA message
1527 * (4 byte channel id + buf)
1529 packet_send_ignore(4 + len);
1533 buffer_consume(&c->output, len);
1534 if (compat20 && len > 0) {
1535 c->local_consumed += len;
1542 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1544 char buf[CHAN_RBUF];
1547 /** XXX handle drain efd, too */
1549 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1550 FD_ISSET(c->efd, writeset) &&
1551 buffer_len(&c->extended) > 0) {
1552 len = write(c->efd, buffer_ptr(&c->extended),
1553 buffer_len(&c->extended));
1554 debug2("channel %d: written %d to efd %d",
1555 c->self, len, c->efd);
1556 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1559 debug2("channel %d: closing write-efd %d",
1561 channel_close_fd(&c->efd);
1563 buffer_consume(&c->extended, len);
1564 c->local_consumed += len;
1566 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1567 FD_ISSET(c->efd, readset)) {
1568 len = read(c->efd, buf, sizeof(buf));
1569 debug2("channel %d: read %d from efd %d",
1570 c->self, len, c->efd);
1571 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1574 debug2("channel %d: closing read-efd %d",
1576 channel_close_fd(&c->efd);
1578 buffer_append(&c->extended, buf, len);
1586 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1591 /* Monitor control fd to detect if the slave client exits */
1592 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1593 len = read(c->ctl_fd, buf, sizeof(buf));
1594 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1597 debug2("channel %d: ctl read<=0", c->self);
1598 if (c->type != SSH_CHANNEL_OPEN) {
1599 debug2("channel %d: not open", c->self);
1603 chan_read_failed(c);
1604 chan_write_failed(c);
1608 fatal("%s: unexpected data on ctl fd", __func__);
1614 channel_check_window(Channel *c)
1616 if (c->type == SSH_CHANNEL_OPEN &&
1617 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1618 c->local_window < c->local_window_max/2 &&
1619 c->local_consumed > 0) {
1620 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1621 packet_put_int(c->remote_id);
1622 packet_put_int(c->local_consumed);
1624 debug2("channel %d: window %d sent adjust %d",
1625 c->self, c->local_window,
1627 c->local_window += c->local_consumed;
1628 c->local_consumed = 0;
1634 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1638 channel_handle_rfd(c, readset, writeset);
1639 channel_handle_wfd(c, readset, writeset);
1642 channel_handle_efd(c, readset, writeset);
1643 channel_handle_ctl(c, readset, writeset);
1644 channel_check_window(c);
1648 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1652 /* Send buffered output data to the socket. */
1653 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1654 len = write(c->sock, buffer_ptr(&c->output),
1655 buffer_len(&c->output));
1657 buffer_clear(&c->output);
1659 buffer_consume(&c->output, len);
1664 channel_handler_init_20(void)
1666 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1667 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1668 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1669 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1670 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1671 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1672 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1673 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1675 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1676 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1677 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1678 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1679 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1680 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1681 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1685 channel_handler_init_13(void)
1687 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1688 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1689 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1690 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1691 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1692 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1693 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1694 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1695 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1697 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1698 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1699 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1700 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1701 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1702 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1703 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1707 channel_handler_init_15(void)
1709 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1710 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1711 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1712 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1713 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1714 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1715 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1717 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1718 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1719 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1720 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1721 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1722 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1726 channel_handler_init(void)
1730 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1731 channel_pre[i] = NULL;
1732 channel_post[i] = NULL;
1735 channel_handler_init_20();
1737 channel_handler_init_13();
1739 channel_handler_init_15();
1742 /* gc dead channels */
1744 channel_garbage_collect(Channel *c)
1748 if (c->detach_user != NULL) {
1749 if (!chan_is_dead(c, c->detach_close))
1751 debug2("channel %d: gc: notify user", c->self);
1752 c->detach_user(c->self, NULL);
1753 /* if we still have a callback */
1754 if (c->detach_user != NULL)
1756 debug2("channel %d: gc: user detached", c->self);
1758 if (!chan_is_dead(c, 1))
1760 debug2("channel %d: garbage collecting", c->self);
1765 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1767 static int did_init = 0;
1772 channel_handler_init();
1775 for (i = 0; i < channels_alloc; i++) {
1779 if (ftab[c->type] != NULL)
1780 (*ftab[c->type])(c, readset, writeset);
1781 channel_garbage_collect(c);
1786 * Allocate/update select bitmasks and add any bits relevant to channels in
1790 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1791 u_int *nallocp, int rekeying)
1795 n = MAX(*maxfdp, channel_max_fd);
1797 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1798 /* perhaps check sz < nalloc/2 and shrink? */
1799 if (*readsetp == NULL || sz > *nallocp) {
1800 *readsetp = xrealloc(*readsetp, sz);
1801 *writesetp = xrealloc(*writesetp, sz);
1805 memset(*readsetp, 0, sz);
1806 memset(*writesetp, 0, sz);
1809 channel_handler(channel_pre, *readsetp, *writesetp);
1813 * After select, perform any appropriate operations for channels which have
1817 channel_after_select(fd_set *readset, fd_set *writeset)
1819 channel_handler(channel_post, readset, writeset);
1823 /* If there is data to send to the connection, enqueue some of it now. */
1825 channel_output_poll(void)
1830 for (i = 0; i < channels_alloc; i++) {
1836 * We are only interested in channels that can have buffered
1840 if (c->type != SSH_CHANNEL_OPEN &&
1841 c->type != SSH_CHANNEL_INPUT_DRAINING)
1844 if (c->type != SSH_CHANNEL_OPEN)
1848 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1849 /* XXX is this true? */
1850 debug3("channel %d: will not send data after close", c->self);
1854 /* Get the amount of buffered data for this channel. */
1855 if ((c->istate == CHAN_INPUT_OPEN ||
1856 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1857 (len = buffer_len(&c->input)) > 0) {
1863 data = buffer_get_string(&c->input,
1865 packet_start(SSH2_MSG_CHANNEL_DATA);
1866 packet_put_int(c->remote_id);
1867 packet_put_string(data, dlen);
1869 c->remote_window -= dlen + 4;
1875 * Send some data for the other side over the secure
1879 if (len > c->remote_window)
1880 len = c->remote_window;
1881 if (len > c->remote_maxpacket)
1882 len = c->remote_maxpacket;
1884 if (packet_is_interactive()) {
1888 /* Keep the packets at reasonable size. */
1889 if (len > packet_get_maxsize()/2)
1890 len = packet_get_maxsize()/2;
1894 packet_start(compat20 ?
1895 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1896 packet_put_int(c->remote_id);
1897 packet_put_string(buffer_ptr(&c->input), len);
1899 buffer_consume(&c->input, len);
1900 c->remote_window -= len;
1902 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1904 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1906 * input-buffer is empty and read-socket shutdown:
1907 * tell peer, that we will not send more data: send IEOF.
1908 * hack for extended data: delay EOF if EFD still in use.
1910 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1911 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1912 c->self, c->efd, buffer_len(&c->extended));
1916 /* Send extended data, i.e. stderr */
1918 !(c->flags & CHAN_EOF_SENT) &&
1919 c->remote_window > 0 &&
1920 (len = buffer_len(&c->extended)) > 0 &&
1921 c->extended_usage == CHAN_EXTENDED_READ) {
1922 debug2("channel %d: rwin %u elen %u euse %d",
1923 c->self, c->remote_window, buffer_len(&c->extended),
1925 if (len > c->remote_window)
1926 len = c->remote_window;
1927 if (len > c->remote_maxpacket)
1928 len = c->remote_maxpacket;
1929 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1930 packet_put_int(c->remote_id);
1931 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1932 packet_put_string(buffer_ptr(&c->extended), len);
1934 buffer_consume(&c->extended, len);
1935 c->remote_window -= len;
1936 debug2("channel %d: sent ext data %d", c->self, len);
1942 /* -- protocol input */
1944 channel_input_data(int type, u_int32_t seq, void *ctxt)
1951 /* Get the channel number and verify it. */
1952 id = packet_get_int();
1953 c = channel_lookup(id);
1955 packet_disconnect("Received data for nonexistent channel %d.", id);
1957 /* Ignore any data for non-open channels (might happen on close) */
1958 if (c->type != SSH_CHANNEL_OPEN &&
1959 c->type != SSH_CHANNEL_X11_OPEN)
1963 data = packet_get_string(&data_len);
1966 * Ignore data for protocol > 1.3 if output end is no longer open.
1967 * For protocol 2 the sending side is reducing its window as it sends
1968 * data, so we must 'fake' consumption of the data in order to ensure
1969 * that window updates are sent back. Otherwise the connection might
1972 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1974 c->local_window -= data_len;
1975 c->local_consumed += data_len;
1982 if (data_len > c->local_maxpacket) {
1983 logit("channel %d: rcvd big packet %d, maxpack %d",
1984 c->self, data_len, c->local_maxpacket);
1986 if (data_len > c->local_window) {
1987 logit("channel %d: rcvd too much data %d, win %d",
1988 c->self, data_len, c->local_window);
1992 c->local_window -= data_len;
1996 buffer_put_string(&c->output, data, data_len);
1998 buffer_append(&c->output, data, data_len);
2003 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2007 u_int data_len, tcode;
2010 /* Get the channel number and verify it. */
2011 id = packet_get_int();
2012 c = channel_lookup(id);
2015 packet_disconnect("Received extended_data for bad channel %d.", id);
2016 if (c->type != SSH_CHANNEL_OPEN) {
2017 logit("channel %d: ext data for non open", id);
2020 if (c->flags & CHAN_EOF_RCVD) {
2021 if (datafellows & SSH_BUG_EXTEOF)
2022 debug("channel %d: accepting ext data after eof", id);
2024 packet_disconnect("Received extended_data after EOF "
2025 "on channel %d.", id);
2027 tcode = packet_get_int();
2029 c->extended_usage != CHAN_EXTENDED_WRITE ||
2030 tcode != SSH2_EXTENDED_DATA_STDERR) {
2031 logit("channel %d: bad ext data", c->self);
2034 data = packet_get_string(&data_len);
2036 if (data_len > c->local_window) {
2037 logit("channel %d: rcvd too much extended_data %d, win %d",
2038 c->self, data_len, c->local_window);
2042 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2043 c->local_window -= data_len;
2044 buffer_append(&c->extended, data, data_len);
2049 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2054 id = packet_get_int();
2056 c = channel_lookup(id);
2058 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2061 /* XXX force input close */
2062 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2063 debug("channel %d: FORCE input drain", c->self);
2064 c->istate = CHAN_INPUT_WAIT_DRAIN;
2065 if (buffer_len(&c->input) == 0)
2072 channel_input_close(int type, u_int32_t seq, void *ctxt)
2077 id = packet_get_int();
2079 c = channel_lookup(id);
2081 packet_disconnect("Received close for nonexistent channel %d.", id);
2084 * Send a confirmation that we have closed the channel and no more
2085 * data is coming for it.
2087 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2088 packet_put_int(c->remote_id);
2092 * If the channel is in closed state, we have sent a close request,
2093 * and the other side will eventually respond with a confirmation.
2094 * Thus, we cannot free the channel here, because then there would be
2095 * no-one to receive the confirmation. The channel gets freed when
2096 * the confirmation arrives.
2098 if (c->type != SSH_CHANNEL_CLOSED) {
2100 * Not a closed channel - mark it as draining, which will
2101 * cause it to be freed later.
2103 buffer_clear(&c->input);
2104 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2108 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2110 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2112 int id = packet_get_int();
2113 Channel *c = channel_lookup(id);
2117 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2118 chan_rcvd_oclose(c);
2122 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2124 int id = packet_get_int();
2125 Channel *c = channel_lookup(id);
2129 packet_disconnect("Received close confirmation for "
2130 "out-of-range channel %d.", id);
2131 if (c->type != SSH_CHANNEL_CLOSED)
2132 packet_disconnect("Received close confirmation for "
2133 "non-closed channel %d (type %d).", id, c->type);
2138 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2143 id = packet_get_int();
2144 c = channel_lookup(id);
2146 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2147 packet_disconnect("Received open confirmation for "
2148 "non-opening channel %d.", id);
2149 remote_id = packet_get_int();
2150 /* Record the remote channel number and mark that the channel is now open. */
2151 c->remote_id = remote_id;
2152 c->type = SSH_CHANNEL_OPEN;
2155 c->remote_window = packet_get_int();
2156 c->remote_maxpacket = packet_get_int();
2158 debug2("callback start");
2159 c->confirm(c->self, c->confirm_ctx);
2160 debug2("callback done");
2162 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2163 c->remote_window, c->remote_maxpacket);
2169 reason2txt(int reason)
2172 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2173 return "administratively prohibited";
2174 case SSH2_OPEN_CONNECT_FAILED:
2175 return "connect failed";
2176 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2177 return "unknown channel type";
2178 case SSH2_OPEN_RESOURCE_SHORTAGE:
2179 return "resource shortage";
2181 return "unknown reason";
2185 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2188 char *msg = NULL, *lang = NULL;
2191 id = packet_get_int();
2192 c = channel_lookup(id);
2194 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2195 packet_disconnect("Received open failure for "
2196 "non-opening channel %d.", id);
2198 reason = packet_get_int();
2199 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2200 msg = packet_get_string(NULL);
2201 lang = packet_get_string(NULL);
2203 logit("channel %d: open failed: %s%s%s", id,
2204 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2211 /* Free the channel. This will also close the socket. */
2216 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2225 /* Get the channel number and verify it. */
2226 id = packet_get_int();
2227 c = channel_lookup(id);
2230 logit("Received window adjust for non-open channel %d.", id);
2233 adjust = packet_get_int();
2235 debug2("channel %d: rcvd adjust %u", id, adjust);
2236 c->remote_window += adjust;
2240 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2244 char *host, *originator_string;
2245 int remote_id, sock = -1;
2247 remote_id = packet_get_int();
2248 host = packet_get_string(NULL);
2249 host_port = packet_get_int();
2251 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2252 originator_string = packet_get_string(NULL);
2254 originator_string = xstrdup("unknown (remote did not supply name)");
2257 sock = channel_connect_to(host, host_port);
2259 c = channel_new("connected socket",
2260 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2261 originator_string, 1);
2262 c->remote_id = remote_id;
2264 xfree(originator_string);
2266 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2267 packet_put_int(remote_id);
2274 /* -- tcp forwarding */
2277 channel_set_af(int af)
2283 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2284 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2287 int sock, r, success = 0, wildcard = 0, is_client;
2288 struct addrinfo hints, *ai, *aitop;
2289 const char *host, *addr;
2290 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2292 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2293 listen_addr : host_to_connect;
2294 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2297 error("No forward host name.");
2300 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2301 error("Forward host name too long.");
2306 * Determine whether or not a port forward listens to loopback,
2307 * specified address or wildcard. On the client, a specified bind
2308 * address will always override gateway_ports. On the server, a
2309 * gateway_ports of 1 (``yes'') will override the client's
2310 * specification and force a wildcard bind, whereas a value of 2
2311 * (``clientspecified'') will bind to whatever address the client
2314 * Special-case listen_addrs are:
2316 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2317 * "" (empty string), "*" -> wildcard v4/v6
2318 * "localhost" -> loopback v4/v6
2321 if (listen_addr == NULL) {
2322 /* No address specified: default to gateway_ports setting */
2325 } else if (gateway_ports || is_client) {
2326 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2327 strcmp(listen_addr, "0.0.0.0") == 0) ||
2328 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2329 (!is_client && gateway_ports == 1))
2331 else if (strcmp(listen_addr, "localhost") != 0)
2335 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2336 type, wildcard, (addr == NULL) ? "NULL" : addr);
2339 * getaddrinfo returns a loopback address if the hostname is
2340 * set to NULL and hints.ai_flags is not AI_PASSIVE
2342 memset(&hints, 0, sizeof(hints));
2343 hints.ai_family = IPv4or6;
2344 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2345 hints.ai_socktype = SOCK_STREAM;
2346 snprintf(strport, sizeof strport, "%d", listen_port);
2347 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2349 /* This really shouldn't happen */
2350 packet_disconnect("getaddrinfo: fatal error: %s",
2353 error("channel_setup_fwd_listener: "
2354 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2359 for (ai = aitop; ai; ai = ai->ai_next) {
2360 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2362 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2363 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2364 error("channel_setup_fwd_listener: getnameinfo failed");
2367 /* Create a port to listen for the host. */
2368 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2370 /* this is no error since kernel may not support ipv6 */
2371 verbose("socket: %.100s", strerror(errno));
2375 channel_set_reuseaddr(sock);
2377 debug("Local forwarding listening on %s port %s.", ntop, strport);
2379 /* Bind the socket to the address. */
2380 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2381 /* address can be in use ipv6 address is already bound */
2383 error("bind: %.100s", strerror(errno));
2385 verbose("bind: %.100s", strerror(errno));
2390 /* Start listening for connections on the socket. */
2391 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2392 error("listen: %.100s", strerror(errno));
2396 /* Allocate a channel number for the socket. */
2397 c = channel_new("port listener", type, sock, sock, -1,
2398 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2399 0, "port listener", 1);
2400 strlcpy(c->path, host, sizeof(c->path));
2401 c->host_port = port_to_connect;
2402 c->listening_port = listen_port;
2406 error("channel_setup_fwd_listener: cannot listen to port: %d",
2408 freeaddrinfo(aitop);
2413 channel_cancel_rport_listener(const char *host, u_short port)
2418 for (i = 0; i < channels_alloc; i++) {
2419 Channel *c = channels[i];
2421 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2422 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2423 c->listening_port == port) {
2424 debug2("%s: close channel %d", __func__, i);
2433 /* protocol local port fwd, used by ssh (and sshd in v1) */
2435 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2436 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2438 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2439 listen_host, listen_port, host_to_connect, port_to_connect,
2443 /* protocol v2 remote port fwd, used by sshd */
2445 channel_setup_remote_fwd_listener(const char *listen_address,
2446 u_short listen_port, int gateway_ports)
2448 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2449 listen_address, listen_port, NULL, 0, gateway_ports);
2453 * Initiate forwarding of connections to port "port" on remote host through
2454 * the secure channel to host:port from local side.
2458 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2459 const char *host_to_connect, u_short port_to_connect)
2461 int type, success = 0;
2463 /* Record locally that connection to this host/port is permitted. */
2464 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2465 fatal("channel_request_remote_forwarding: too many forwards");
2467 /* Send the forward request to the remote side. */
2469 const char *address_to_bind;
2470 if (listen_host == NULL)
2471 address_to_bind = "localhost";
2472 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2473 address_to_bind = "";
2475 address_to_bind = listen_host;
2477 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2478 packet_put_cstring("tcpip-forward");
2479 packet_put_char(1); /* boolean: want reply */
2480 packet_put_cstring(address_to_bind);
2481 packet_put_int(listen_port);
2483 packet_write_wait();
2484 /* Assume that server accepts the request */
2487 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2488 packet_put_int(listen_port);
2489 packet_put_cstring(host_to_connect);
2490 packet_put_int(port_to_connect);
2492 packet_write_wait();
2494 /* Wait for response from the remote side. */
2495 type = packet_read();
2497 case SSH_SMSG_SUCCESS:
2500 case SSH_SMSG_FAILURE:
2501 logit("Warning: Server denied remote port forwarding.");
2504 /* Unknown packet */
2505 packet_disconnect("Protocol error for port forward request:"
2506 "received packet type %d.", type);
2510 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2511 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2512 permitted_opens[num_permitted_opens].listen_port = listen_port;
2513 num_permitted_opens++;
2518 * Request cancellation of remote forwarding of connection host:port from
2522 channel_request_rforward_cancel(const char *host, u_short port)
2529 for (i = 0; i < num_permitted_opens; i++) {
2530 if (permitted_opens[i].host_to_connect != NULL &&
2531 permitted_opens[i].listen_port == port)
2534 if (i >= num_permitted_opens) {
2535 debug("%s: requested forward not found", __func__);
2538 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2539 packet_put_cstring("cancel-tcpip-forward");
2541 packet_put_cstring(host == NULL ? "" : host);
2542 packet_put_int(port);
2545 permitted_opens[i].listen_port = 0;
2546 permitted_opens[i].port_to_connect = 0;
2547 xfree(permitted_opens[i].host_to_connect);
2548 permitted_opens[i].host_to_connect = NULL;
2552 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2553 * listening for the port, and sends back a success reply (or disconnect
2554 * message if there was an error). This never returns if there was an error.
2557 channel_input_port_forward_request(int is_root, int gateway_ports)
2559 u_short port, host_port;
2562 /* Get arguments from the packet. */
2563 port = packet_get_int();
2564 hostname = packet_get_string(NULL);
2565 host_port = packet_get_int();
2569 * Check that an unprivileged user is not trying to forward a
2572 if (port < IPPORT_RESERVED && !is_root)
2574 "Requested forwarding of port %d but user is not root.",
2577 packet_disconnect("Dynamic forwarding denied.");
2580 /* Initiate forwarding */
2581 channel_setup_local_fwd_listener(NULL, port, hostname,
2582 host_port, gateway_ports);
2584 /* Free the argument string. */
2589 * Permits opening to any host/port if permitted_opens[] is empty. This is
2590 * usually called by the server, because the user could connect to any port
2591 * anyway, and the server has no way to know but to trust the client anyway.
2594 channel_permit_all_opens(void)
2596 if (num_permitted_opens == 0)
2597 all_opens_permitted = 1;
2601 channel_add_permitted_opens(char *host, int port)
2603 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2604 fatal("channel_request_remote_forwarding: too many forwards");
2605 debug("allow port forwarding to host %s port %d", host, port);
2607 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2608 permitted_opens[num_permitted_opens].port_to_connect = port;
2609 num_permitted_opens++;
2611 all_opens_permitted = 0;
2615 channel_clear_permitted_opens(void)
2619 for (i = 0; i < num_permitted_opens; i++)
2620 if (permitted_opens[i].host_to_connect != NULL)
2621 xfree(permitted_opens[i].host_to_connect);
2622 num_permitted_opens = 0;
2626 /* return socket to remote host, port */
2628 connect_to(const char *host, u_short port)
2630 struct addrinfo hints, *ai, *aitop;
2631 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2635 memset(&hints, 0, sizeof(hints));
2636 hints.ai_family = IPv4or6;
2637 hints.ai_socktype = SOCK_STREAM;
2638 snprintf(strport, sizeof strport, "%d", port);
2639 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2640 error("connect_to %.100s: unknown host (%s)", host,
2641 gai_strerror(gaierr));
2644 for (ai = aitop; ai; ai = ai->ai_next) {
2645 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2647 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2648 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2649 error("connect_to: getnameinfo failed");
2652 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2654 if (ai->ai_next == NULL)
2655 error("socket: %.100s", strerror(errno));
2657 verbose("socket: %.100s", strerror(errno));
2660 if (set_nonblock(sock) == -1)
2661 fatal("%s: set_nonblock(%d)", __func__, sock);
2662 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2663 errno != EINPROGRESS) {
2664 error("connect_to %.100s port %s: %.100s", ntop, strport,
2667 continue; /* fail -- try next */
2669 break; /* success */
2672 freeaddrinfo(aitop);
2674 error("connect_to %.100s port %d: failed.", host, port);
2683 channel_connect_by_listen_address(u_short listen_port)
2687 for (i = 0; i < num_permitted_opens; i++)
2688 if (permitted_opens[i].host_to_connect != NULL &&
2689 permitted_opens[i].listen_port == listen_port)
2691 permitted_opens[i].host_to_connect,
2692 permitted_opens[i].port_to_connect);
2693 error("WARNING: Server requests forwarding for unknown listen_port %d",
2698 /* Check if connecting to that port is permitted and connect. */
2700 channel_connect_to(const char *host, u_short port)
2704 permit = all_opens_permitted;
2706 for (i = 0; i < num_permitted_opens; i++)
2707 if (permitted_opens[i].host_to_connect != NULL &&
2708 permitted_opens[i].port_to_connect == port &&
2709 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2714 logit("Received request to connect to host %.100s port %d, "
2715 "but the request was denied.", host, port);
2718 return connect_to(host, port);
2722 channel_send_window_changes(void)
2727 for (i = 0; i < channels_alloc; i++) {
2728 if (channels[i] == NULL || !channels[i]->client_tty ||
2729 channels[i]->type != SSH_CHANNEL_OPEN)
2731 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2733 channel_request_start(i, "window-change", 0);
2734 packet_put_int((u_int)ws.ws_col);
2735 packet_put_int((u_int)ws.ws_row);
2736 packet_put_int((u_int)ws.ws_xpixel);
2737 packet_put_int((u_int)ws.ws_ypixel);
2742 /* -- X11 forwarding */
2745 * Creates an internet domain socket for listening for X11 connections.
2746 * Returns 0 and a suitable display number for the DISPLAY variable
2747 * stored in display_numberp , or -1 if an error occurs.
2750 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2751 int single_connection, u_int *display_numberp, int **chanids)
2754 int display_number, sock;
2756 struct addrinfo hints, *ai, *aitop;
2757 char strport[NI_MAXSERV];
2758 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2760 if (chanids == NULL)
2763 for (display_number = x11_display_offset;
2764 display_number < MAX_DISPLAYS;
2766 port = 6000 + display_number;
2767 memset(&hints, 0, sizeof(hints));
2768 hints.ai_family = IPv4or6;
2769 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2770 hints.ai_socktype = SOCK_STREAM;
2771 snprintf(strport, sizeof strport, "%d", port);
2772 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2773 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2776 for (ai = aitop; ai; ai = ai->ai_next) {
2777 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2779 sock = socket(ai->ai_family, ai->ai_socktype,
2782 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2783 error("socket: %.100s", strerror(errno));
2784 freeaddrinfo(aitop);
2787 debug("x11_create_display_inet: Socket family %d not supported",
2793 if (ai->ai_family == AF_INET6) {
2795 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2796 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2799 channel_set_reuseaddr(sock);
2800 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2801 debug2("bind port %d: %.100s", port, strerror(errno));
2807 for (n = 0; n < num_socks; n++) {
2813 socks[num_socks++] = sock;
2814 #ifndef DONT_TRY_OTHER_AF
2815 if (num_socks == NUM_SOCKS)
2818 if (x11_use_localhost) {
2819 if (num_socks == NUM_SOCKS)
2826 freeaddrinfo(aitop);
2830 if (display_number >= MAX_DISPLAYS) {
2831 error("Failed to allocate internet-domain X11 display socket.");
2834 /* Start listening for connections on the socket. */
2835 for (n = 0; n < num_socks; n++) {
2837 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2838 error("listen: %.100s", strerror(errno));
2844 /* Allocate a channel for each socket. */
2845 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
2846 for (n = 0; n < num_socks; n++) {
2848 nc = channel_new("x11 listener",
2849 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2850 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2851 0, "X11 inet listener", 1);
2852 nc->single_connection = single_connection;
2853 (*chanids)[n] = nc->self;
2857 /* Return the display number for the DISPLAY environment variable. */
2858 *display_numberp = display_number;
2863 connect_local_xsocket(u_int dnr)
2866 struct sockaddr_un addr;
2868 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2870 error("socket: %.100s", strerror(errno));
2871 memset(&addr, 0, sizeof(addr));
2872 addr.sun_family = AF_UNIX;
2873 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2874 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
2877 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2882 x11_connect_display(void)
2884 int display_number, sock = 0;
2885 const char *display;
2886 char buf[1024], *cp;
2887 struct addrinfo hints, *ai, *aitop;
2888 char strport[NI_MAXSERV];
2891 /* Try to open a socket for the local X server. */
2892 display = getenv("DISPLAY");
2894 error("DISPLAY not set.");
2898 * Now we decode the value of the DISPLAY variable and make a
2899 * connection to the real X server.
2903 * Check if it is a unix domain socket. Unix domain displays are in
2904 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2906 if (strncmp(display, "unix:", 5) == 0 ||
2907 display[0] == ':') {
2908 /* Connect to the unix domain socket. */
2909 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2910 error("Could not parse display number from DISPLAY: %.100s",
2914 /* Create a socket. */
2915 sock = connect_local_xsocket(display_number);
2919 /* OK, we now have a connection to the display. */
2923 * Connect to an inet socket. The DISPLAY value is supposedly
2924 * hostname:d[.s], where hostname may also be numeric IP address.
2926 strlcpy(buf, display, sizeof(buf));
2927 cp = strchr(buf, ':');
2929 error("Could not find ':' in DISPLAY: %.100s", display);
2933 /* buf now contains the host name. But first we parse the display number. */
2934 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2935 error("Could not parse display number from DISPLAY: %.100s",
2940 /* Look up the host address */
2941 memset(&hints, 0, sizeof(hints));
2942 hints.ai_family = IPv4or6;
2943 hints.ai_socktype = SOCK_STREAM;
2944 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2945 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2946 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2949 for (ai = aitop; ai; ai = ai->ai_next) {
2950 /* Create a socket. */
2951 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2953 debug2("socket: %.100s", strerror(errno));
2956 /* Connect it to the display. */
2957 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2958 debug2("connect %.100s port %d: %.100s", buf,
2959 6000 + display_number, strerror(errno));
2966 freeaddrinfo(aitop);
2968 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2977 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2978 * the remote channel number. We should do whatever we want, and respond
2979 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2983 x11_input_open(int type, u_int32_t seq, void *ctxt)
2986 int remote_id, sock = 0;
2989 debug("Received X11 open request.");
2991 remote_id = packet_get_int();
2993 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2994 remote_host = packet_get_string(NULL);
2996 remote_host = xstrdup("unknown (remote did not supply name)");
3000 /* Obtain a connection to the real X display. */
3001 sock = x11_connect_display();
3003 /* Allocate a channel for this connection. */
3004 c = channel_new("connected x11 socket",
3005 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3007 c->remote_id = remote_id;
3012 /* Send refusal to the remote host. */
3013 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3014 packet_put_int(remote_id);
3016 /* Send a confirmation to the remote host. */
3017 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3018 packet_put_int(remote_id);
3019 packet_put_int(c->self);
3024 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3026 deny_input_open(int type, u_int32_t seq, void *ctxt)
3028 int rchan = packet_get_int();
3031 case SSH_SMSG_AGENT_OPEN:
3032 error("Warning: ssh server tried agent forwarding.");
3034 case SSH_SMSG_X11_OPEN:
3035 error("Warning: ssh server tried X11 forwarding.");
3038 error("deny_input_open: type %d", type);
3041 error("Warning: this is probably a break-in attempt by a malicious server.");
3042 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3043 packet_put_int(rchan);
3048 * Requests forwarding of X11 connections, generates fake authentication
3049 * data, and enables authentication spoofing.
3050 * This should be called in the client only.
3053 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3054 const char *proto, const char *data)
3056 u_int data_len = (u_int) strlen(data) / 2;
3063 if (x11_saved_display == NULL)
3064 x11_saved_display = xstrdup(disp);
3065 else if (strcmp(disp, x11_saved_display) != 0) {
3066 error("x11_request_forwarding_with_spoofing: different "
3067 "$DISPLAY already forwarded");
3073 cp = strchr(disp, ':');
3075 cp = strchr(cp, '.');
3077 screen_number = atoi(cp + 1);
3081 if (x11_saved_proto == NULL) {
3082 /* Save protocol name. */
3083 x11_saved_proto = xstrdup(proto);
3085 * Extract real authentication data and generate fake data
3086 * of the same length.
3088 x11_saved_data = xmalloc(data_len);
3089 x11_fake_data = xmalloc(data_len);
3090 for (i = 0; i < data_len; i++) {
3091 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3092 fatal("x11_request_forwarding: bad "
3093 "authentication data: %.100s", data);
3096 x11_saved_data[i] = value;
3097 x11_fake_data[i] = rnd & 0xff;
3100 x11_saved_data_len = data_len;
3101 x11_fake_data_len = data_len;
3104 /* Convert the fake data into hex. */
3105 new_data = tohex(x11_fake_data, data_len);
3107 /* Send the request packet. */
3109 channel_request_start(client_session_id, "x11-req", 0);
3110 packet_put_char(0); /* XXX bool single connection */
3112 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3114 packet_put_cstring(proto);
3115 packet_put_cstring(new_data);
3116 packet_put_int(screen_number);
3118 packet_write_wait();
3123 /* -- agent forwarding */
3125 /* Sends a message to the server to request authentication fd forwarding. */
3128 auth_request_forwarding(void)
3130 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3132 packet_write_wait();