2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
15 * SSH2 support added by Markus Friedl.
16 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 RCSID("$OpenBSD: channels.c,v 1.233 2006/02/07 01:42:00 stevesk Exp $");
58 #include "pathnames.h"
64 * Pointer to an array containing all allocated channels. The array is
65 * dynamically extended as needed.
67 static Channel **channels = NULL;
70 * Size of the channel array. All slots of the array must always be
71 * initialized (at least the type field); unused slots set to NULL
73 static u_int channels_alloc = 0;
76 * Maximum file descriptor value used in any of the channels. This is
77 * updated in channel_new.
79 static int channel_max_fd = 0;
82 /* -- tcp forwarding */
85 * Data structure for storing which hosts are permitted for forward requests.
86 * The local sides of any remote forwards are stored in this array to prevent
87 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
88 * network (which might be behind a firewall).
91 char *host_to_connect; /* Connect to 'host'. */
92 u_short port_to_connect; /* Connect to 'port'. */
93 u_short listen_port; /* Remote side should listen port number. */
96 /* List of all permitted host/port pairs to connect. */
97 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
99 /* Number of permitted host/port pairs in the array. */
100 static int num_permitted_opens = 0;
102 * If this is true, all opens are permitted. This is the case on the server
103 * on which we have to trust the client anyway, and the user could do
104 * anything after logging in anyway.
106 static int all_opens_permitted = 0;
109 /* -- X11 forwarding */
111 /* Maximum number of fake X11 displays to try. */
112 #define MAX_DISPLAYS 1000
114 /* Saved X11 local (client) display. */
115 static char *x11_saved_display = NULL;
117 /* Saved X11 authentication protocol name. */
118 static char *x11_saved_proto = NULL;
120 /* Saved X11 authentication data. This is the real data. */
121 static char *x11_saved_data = NULL;
122 static u_int x11_saved_data_len = 0;
125 * Fake X11 authentication data. This is what the server will be sending us;
126 * we should replace any occurrences of this by the real data.
128 static char *x11_fake_data = NULL;
129 static u_int x11_fake_data_len;
132 /* -- agent forwarding */
136 /* AF_UNSPEC or AF_INET or AF_INET6 */
137 static int IPv4or6 = AF_UNSPEC;
140 static void port_open_helper(Channel *c, char *rtype);
142 /* -- channel core */
145 channel_by_id(int id)
149 if (id < 0 || (u_int)id >= channels_alloc) {
150 logit("channel_by_id: %d: bad id", id);
155 logit("channel_by_id: %d: bad id: channel free", id);
162 * Returns the channel if it is allowed to receive protocol messages.
163 * Private channels, like listening sockets, may not receive messages.
166 channel_lookup(int id)
170 if ((c = channel_by_id(id)) == NULL)
174 case SSH_CHANNEL_X11_OPEN:
175 case SSH_CHANNEL_LARVAL:
176 case SSH_CHANNEL_CONNECTING:
177 case SSH_CHANNEL_DYNAMIC:
178 case SSH_CHANNEL_OPENING:
179 case SSH_CHANNEL_OPEN:
180 case SSH_CHANNEL_INPUT_DRAINING:
181 case SSH_CHANNEL_OUTPUT_DRAINING:
185 logit("Non-public channel %d, type %d.", id, c->type);
190 * Register filedescriptors for a channel, used when allocating a channel or
191 * when the channel consumer/producer is ready, e.g. shell exec'd
195 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
196 int extusage, int nonblock)
198 /* Update the maximum file descriptor value. */
199 channel_max_fd = MAX(channel_max_fd, rfd);
200 channel_max_fd = MAX(channel_max_fd, wfd);
201 channel_max_fd = MAX(channel_max_fd, efd);
203 /* XXX set close-on-exec -markus */
207 c->sock = (rfd == wfd) ? rfd : -1;
208 c->ctl_fd = -1; /* XXX: set elsewhere */
210 c->extended_usage = extusage;
212 /* XXX ugly hack: nonblock is only set by the server */
213 if (nonblock && isatty(c->rfd)) {
214 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
216 if (!isatty(c->wfd)) {
217 error("channel %d: wfd %d is not a tty?",
223 c->wfd_isatty = isatty(c->wfd);
225 /* enable nonblocking mode */
237 * Allocate a new channel object and set its type and socket. This will cause
238 * 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. */
344 channel_close_fds(Channel *c)
346 debug3("channel %d: close_fds r %d w %d e %d c %d",
347 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
349 channel_close_fd(&c->sock);
350 channel_close_fd(&c->ctl_fd);
351 channel_close_fd(&c->rfd);
352 channel_close_fd(&c->wfd);
353 channel_close_fd(&c->efd);
356 /* Free the channel and close its fd/socket. */
359 channel_free(Channel *c)
364 for (n = 0, i = 0; i < channels_alloc; i++)
367 debug("channel %d: free: %s, nchannels %u", c->self,
368 c->remote_name ? c->remote_name : "???", n);
370 s = channel_open_message();
371 debug3("channel %d: status: %s", c->self, s);
375 shutdown(c->sock, SHUT_RDWR);
377 shutdown(c->ctl_fd, SHUT_RDWR);
378 channel_close_fds(c);
379 buffer_free(&c->input);
380 buffer_free(&c->output);
381 buffer_free(&c->extended);
382 if (c->remote_name) {
383 xfree(c->remote_name);
384 c->remote_name = NULL;
386 channels[c->self] = NULL;
391 channel_free_all(void)
395 for (i = 0; i < channels_alloc; i++)
396 if (channels[i] != NULL)
397 channel_free(channels[i]);
401 * Closes the sockets/fds of all channels. This is used to close extra file
402 * descriptors after a fork.
406 channel_close_all(void)
410 for (i = 0; i < channels_alloc; i++)
411 if (channels[i] != NULL)
412 channel_close_fds(channels[i]);
416 * Stop listening to channels.
420 channel_stop_listening(void)
425 for (i = 0; i < channels_alloc; i++) {
429 case SSH_CHANNEL_AUTH_SOCKET:
430 case SSH_CHANNEL_PORT_LISTENER:
431 case SSH_CHANNEL_RPORT_LISTENER:
432 case SSH_CHANNEL_X11_LISTENER:
433 channel_close_fd(&c->sock);
442 * Returns true if no channel has too much buffered data, and false if one or
443 * more channel is overfull.
447 channel_not_very_much_buffered_data(void)
452 for (i = 0; i < channels_alloc; i++) {
454 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
457 buffer_len(&c->input) > packet_get_maxsize()) {
458 debug2("channel %d: big input buffer %d",
459 c->self, buffer_len(&c->input));
463 if (buffer_len(&c->output) > packet_get_maxsize()) {
464 debug2("channel %d: big output buffer %u > %u",
465 c->self, buffer_len(&c->output),
466 packet_get_maxsize());
474 /* Returns true if any channel is still open. */
477 channel_still_open(void)
482 for (i = 0; i < channels_alloc; i++) {
487 case SSH_CHANNEL_X11_LISTENER:
488 case SSH_CHANNEL_PORT_LISTENER:
489 case SSH_CHANNEL_RPORT_LISTENER:
490 case SSH_CHANNEL_CLOSED:
491 case SSH_CHANNEL_AUTH_SOCKET:
492 case SSH_CHANNEL_DYNAMIC:
493 case SSH_CHANNEL_CONNECTING:
494 case SSH_CHANNEL_ZOMBIE:
496 case SSH_CHANNEL_LARVAL:
498 fatal("cannot happen: SSH_CHANNEL_LARVAL");
500 case SSH_CHANNEL_OPENING:
501 case SSH_CHANNEL_OPEN:
502 case SSH_CHANNEL_X11_OPEN:
504 case SSH_CHANNEL_INPUT_DRAINING:
505 case SSH_CHANNEL_OUTPUT_DRAINING:
507 fatal("cannot happen: OUT_DRAIN");
510 fatal("channel_still_open: bad channel type %d", c->type);
517 /* Returns the id of an open channel suitable for keepaliving */
520 channel_find_open(void)
525 for (i = 0; i < channels_alloc; i++) {
527 if (c == NULL || c->remote_id < 0)
530 case SSH_CHANNEL_CLOSED:
531 case SSH_CHANNEL_DYNAMIC:
532 case SSH_CHANNEL_X11_LISTENER:
533 case SSH_CHANNEL_PORT_LISTENER:
534 case SSH_CHANNEL_RPORT_LISTENER:
535 case SSH_CHANNEL_OPENING:
536 case SSH_CHANNEL_CONNECTING:
537 case SSH_CHANNEL_ZOMBIE:
539 case SSH_CHANNEL_LARVAL:
540 case SSH_CHANNEL_AUTH_SOCKET:
541 case SSH_CHANNEL_OPEN:
542 case SSH_CHANNEL_X11_OPEN:
544 case SSH_CHANNEL_INPUT_DRAINING:
545 case SSH_CHANNEL_OUTPUT_DRAINING:
547 fatal("cannot happen: OUT_DRAIN");
550 fatal("channel_find_open: bad channel type %d", c->type);
559 * Returns a message describing the currently open forwarded connections,
560 * suitable for sending to the client. The message contains crlf pairs for
565 channel_open_message(void)
572 buffer_init(&buffer);
573 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
574 buffer_append(&buffer, buf, strlen(buf));
575 for (i = 0; i < channels_alloc; i++) {
580 case SSH_CHANNEL_X11_LISTENER:
581 case SSH_CHANNEL_PORT_LISTENER:
582 case SSH_CHANNEL_RPORT_LISTENER:
583 case SSH_CHANNEL_CLOSED:
584 case SSH_CHANNEL_AUTH_SOCKET:
585 case SSH_CHANNEL_ZOMBIE:
587 case SSH_CHANNEL_LARVAL:
588 case SSH_CHANNEL_OPENING:
589 case SSH_CHANNEL_CONNECTING:
590 case SSH_CHANNEL_DYNAMIC:
591 case SSH_CHANNEL_OPEN:
592 case SSH_CHANNEL_X11_OPEN:
593 case SSH_CHANNEL_INPUT_DRAINING:
594 case SSH_CHANNEL_OUTPUT_DRAINING:
595 snprintf(buf, sizeof buf,
596 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
597 c->self, c->remote_name,
598 c->type, c->remote_id,
599 c->istate, buffer_len(&c->input),
600 c->ostate, buffer_len(&c->output),
601 c->rfd, c->wfd, c->ctl_fd);
602 buffer_append(&buffer, buf, strlen(buf));
605 fatal("channel_open_message: bad channel type %d", c->type);
609 buffer_append(&buffer, "\0", 1);
610 cp = xstrdup(buffer_ptr(&buffer));
611 buffer_free(&buffer);
616 channel_send_open(int id)
618 Channel *c = channel_lookup(id);
621 logit("channel_send_open: %d: bad id", id);
624 debug2("channel %d: send open", id);
625 packet_start(SSH2_MSG_CHANNEL_OPEN);
626 packet_put_cstring(c->ctype);
627 packet_put_int(c->self);
628 packet_put_int(c->local_window);
629 packet_put_int(c->local_maxpacket);
634 channel_request_start(int id, char *service, int wantconfirm)
636 Channel *c = channel_lookup(id);
639 logit("channel_request_start: %d: unknown channel id", id);
642 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
643 packet_start(SSH2_MSG_CHANNEL_REQUEST);
644 packet_put_int(c->remote_id);
645 packet_put_cstring(service);
646 packet_put_char(wantconfirm);
649 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
651 Channel *c = channel_lookup(id);
654 logit("channel_register_comfirm: %d: bad id", id);
658 c->confirm_ctx = ctx;
661 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
663 Channel *c = channel_by_id(id);
666 logit("channel_register_cleanup: %d: bad id", id);
670 c->detach_close = do_close;
673 channel_cancel_cleanup(int id)
675 Channel *c = channel_by_id(id);
678 logit("channel_cancel_cleanup: %d: bad id", id);
681 c->detach_user = NULL;
685 channel_register_filter(int id, channel_infilter_fn *ifn,
686 channel_outfilter_fn *ofn)
688 Channel *c = channel_lookup(id);
691 logit("channel_register_filter: %d: bad id", id);
694 c->input_filter = ifn;
695 c->output_filter = ofn;
699 channel_set_fds(int id, int rfd, int wfd, int efd,
700 int extusage, int nonblock, u_int window_max)
702 Channel *c = channel_lookup(id);
704 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
705 fatal("channel_activate for non-larval channel %d.", id);
706 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
707 c->type = SSH_CHANNEL_OPEN;
708 c->local_window = c->local_window_max = window_max;
709 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
710 packet_put_int(c->remote_id);
711 packet_put_int(c->local_window);
716 * 'channel_pre*' are called just before select() to add any bits relevant to
717 * channels in the select bitmasks.
720 * 'channel_post*': perform any appropriate operations for channels which
721 * have events pending.
723 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
724 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
725 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
728 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
730 FD_SET(c->sock, readset);
734 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
736 debug3("channel %d: waiting for connection", c->self);
737 FD_SET(c->sock, writeset);
741 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
743 if (buffer_len(&c->input) < packet_get_maxsize())
744 FD_SET(c->sock, readset);
745 if (buffer_len(&c->output) > 0)
746 FD_SET(c->sock, writeset);
750 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
752 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
754 /* check buffer limits */
755 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
757 if (c->istate == CHAN_INPUT_OPEN &&
759 buffer_len(&c->input) < limit)
760 FD_SET(c->rfd, readset);
761 if (c->ostate == CHAN_OUTPUT_OPEN ||
762 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
763 if (buffer_len(&c->output) > 0) {
764 FD_SET(c->wfd, writeset);
765 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
766 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
767 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
768 c->self, c->efd, buffer_len(&c->extended));
773 /** XXX check close conditions, too */
774 if (compat20 && c->efd != -1) {
775 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
776 buffer_len(&c->extended) > 0)
777 FD_SET(c->efd, writeset);
778 else if (!(c->flags & CHAN_EOF_SENT) &&
779 c->extended_usage == CHAN_EXTENDED_READ &&
780 buffer_len(&c->extended) < c->remote_window)
781 FD_SET(c->efd, readset);
783 /* XXX: What about efd? races? */
784 if (compat20 && c->ctl_fd != -1 &&
785 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
786 FD_SET(c->ctl_fd, readset);
790 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
792 if (buffer_len(&c->input) == 0) {
793 packet_start(SSH_MSG_CHANNEL_CLOSE);
794 packet_put_int(c->remote_id);
796 c->type = SSH_CHANNEL_CLOSED;
797 debug2("channel %d: closing after input drain.", c->self);
802 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
804 if (buffer_len(&c->output) == 0)
807 FD_SET(c->sock, writeset);
811 * This is a special state for X11 authentication spoofing. An opened X11
812 * connection (when authentication spoofing is being done) remains in this
813 * state until the first packet has been completely read. The authentication
814 * data in that packet is then substituted by the real data if it matches the
815 * fake data, and the channel is put into normal mode.
816 * XXX All this happens at the client side.
817 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
820 x11_open_helper(Buffer *b)
823 u_int proto_len, data_len;
825 /* Check if the fixed size part of the packet is in buffer. */
826 if (buffer_len(b) < 12)
829 /* Parse the lengths of variable-length fields. */
831 if (ucp[0] == 0x42) { /* Byte order MSB first. */
832 proto_len = 256 * ucp[6] + ucp[7];
833 data_len = 256 * ucp[8] + ucp[9];
834 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
835 proto_len = ucp[6] + 256 * ucp[7];
836 data_len = ucp[8] + 256 * ucp[9];
838 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
843 /* Check if the whole packet is in buffer. */
845 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
848 /* Check if authentication protocol matches. */
849 if (proto_len != strlen(x11_saved_proto) ||
850 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
851 debug2("X11 connection uses different authentication protocol.");
854 /* Check if authentication data matches our fake data. */
855 if (data_len != x11_fake_data_len ||
856 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
857 x11_fake_data, x11_fake_data_len) != 0) {
858 debug2("X11 auth data does not match fake data.");
861 /* Check fake data length */
862 if (x11_fake_data_len != x11_saved_data_len) {
863 error("X11 fake_data_len %d != saved_data_len %d",
864 x11_fake_data_len, x11_saved_data_len);
868 * Received authentication protocol and data match
869 * our fake data. Substitute the fake data with real
872 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
873 x11_saved_data, x11_saved_data_len);
878 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
880 int ret = x11_open_helper(&c->output);
883 /* Start normal processing for the channel. */
884 c->type = SSH_CHANNEL_OPEN;
885 channel_pre_open_13(c, readset, writeset);
886 } else if (ret == -1) {
888 * We have received an X11 connection that has bad
889 * authentication information.
891 logit("X11 connection rejected because of wrong authentication.");
892 buffer_clear(&c->input);
893 buffer_clear(&c->output);
894 channel_close_fd(&c->sock);
896 c->type = SSH_CHANNEL_CLOSED;
897 packet_start(SSH_MSG_CHANNEL_CLOSE);
898 packet_put_int(c->remote_id);
904 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
906 int ret = x11_open_helper(&c->output);
908 /* c->force_drain = 1; */
911 c->type = SSH_CHANNEL_OPEN;
912 channel_pre_open(c, readset, writeset);
913 } else if (ret == -1) {
914 logit("X11 connection rejected because of wrong authentication.");
915 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
917 buffer_clear(&c->input);
919 buffer_clear(&c->output);
920 /* for proto v1, the peer will send an IEOF */
922 chan_write_failed(c);
924 c->type = SSH_CHANNEL_OPEN;
925 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
929 /* try to decode a socks4 header */
931 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
934 u_int len, have, i, found;
940 struct in_addr dest_addr;
943 debug2("channel %d: decode socks4", c->self);
945 have = buffer_len(&c->input);
946 len = sizeof(s4_req);
949 p = buffer_ptr(&c->input);
950 for (found = 0, i = len; i < have; i++) {
956 /* the peer is probably sending garbage */
957 debug("channel %d: decode socks4: too long",
964 buffer_get(&c->input, (char *)&s4_req.version, 1);
965 buffer_get(&c->input, (char *)&s4_req.command, 1);
966 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
967 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
968 have = buffer_len(&c->input);
969 p = buffer_ptr(&c->input);
971 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
973 fatal("channel %d: decode socks4: len %d > have %d",
975 strlcpy(username, p, sizeof(username));
976 buffer_consume(&c->input, len);
977 buffer_consume(&c->input, 1); /* trailing '\0' */
979 host = inet_ntoa(s4_req.dest_addr);
980 strlcpy(c->path, host, sizeof(c->path));
981 c->host_port = ntohs(s4_req.dest_port);
983 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
984 c->self, host, c->host_port, s4_req.command);
986 if (s4_req.command != 1) {
987 debug("channel %d: cannot handle: socks4 cn %d",
988 c->self, s4_req.command);
991 s4_rsp.version = 0; /* vn: 0 for reply */
992 s4_rsp.command = 90; /* cd: req granted */
993 s4_rsp.dest_port = 0; /* ignored */
994 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
995 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
999 /* try to decode a socks5 header */
1000 #define SSH_SOCKS5_AUTHDONE 0x1000
1001 #define SSH_SOCKS5_NOAUTH 0x00
1002 #define SSH_SOCKS5_IPV4 0x01
1003 #define SSH_SOCKS5_DOMAIN 0x03
1004 #define SSH_SOCKS5_IPV6 0x04
1005 #define SSH_SOCKS5_CONNECT 0x01
1006 #define SSH_SOCKS5_SUCCESS 0x00
1009 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
1017 u_int16_t dest_port;
1018 u_char *p, dest_addr[255+1];
1019 u_int have, i, found, nmethods, addrlen, af;
1021 debug2("channel %d: decode socks5", c->self);
1022 p = buffer_ptr(&c->input);
1025 have = buffer_len(&c->input);
1026 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1027 /* format: ver | nmethods | methods */
1031 if (have < nmethods + 2)
1033 /* look for method: "NO AUTHENTICATION REQUIRED" */
1034 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1035 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1041 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1045 buffer_consume(&c->input, nmethods + 2);
1046 buffer_put_char(&c->output, 0x05); /* version */
1047 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1048 FD_SET(c->sock, writeset);
1049 c->flags |= SSH_SOCKS5_AUTHDONE;
1050 debug2("channel %d: socks5 auth done", c->self);
1051 return 0; /* need more */
1053 debug2("channel %d: socks5 post auth", c->self);
1054 if (have < sizeof(s5_req)+1)
1055 return 0; /* need more */
1056 memcpy((char *)&s5_req, p, sizeof(s5_req));
1057 if (s5_req.version != 0x05 ||
1058 s5_req.command != SSH_SOCKS5_CONNECT ||
1059 s5_req.reserved != 0x00) {
1060 debug2("channel %d: only socks5 connect supported", c->self);
1063 switch (s5_req.atyp){
1064 case SSH_SOCKS5_IPV4:
1068 case SSH_SOCKS5_DOMAIN:
1069 addrlen = p[sizeof(s5_req)];
1072 case SSH_SOCKS5_IPV6:
1077 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1080 if (have < 4 + addrlen + 2)
1082 buffer_consume(&c->input, sizeof(s5_req));
1083 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1084 buffer_consume(&c->input, 1); /* host string length */
1085 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1086 buffer_get(&c->input, (char *)&dest_port, 2);
1087 dest_addr[addrlen] = '\0';
1088 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1089 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1090 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1092 c->host_port = ntohs(dest_port);
1094 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1095 c->self, c->path, c->host_port, s5_req.command);
1097 s5_rsp.version = 0x05;
1098 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1099 s5_rsp.reserved = 0; /* ignored */
1100 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1101 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1102 dest_port = 0; /* ignored */
1104 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1105 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1106 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1110 /* dynamic port forwarding */
1112 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1118 have = buffer_len(&c->input);
1120 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1121 /* buffer_dump(&c->input); */
1122 /* check if the fixed size part of the packet is in buffer. */
1125 FD_SET(c->sock, readset);
1128 /* try to guess the protocol */
1129 p = buffer_ptr(&c->input);
1132 ret = channel_decode_socks4(c, readset, writeset);
1135 ret = channel_decode_socks5(c, readset, writeset);
1143 } else if (ret == 0) {
1144 debug2("channel %d: pre_dynamic: need more", c->self);
1146 FD_SET(c->sock, readset);
1148 /* switch to the next state */
1149 c->type = SSH_CHANNEL_OPENING;
1150 port_open_helper(c, "direct-tcpip");
1154 /* This is our fake X11 server socket. */
1156 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1159 struct sockaddr addr;
1162 char buf[16384], *remote_ipaddr;
1165 if (FD_ISSET(c->sock, readset)) {
1166 debug("X11 connection requested.");
1167 addrlen = sizeof(addr);
1168 newsock = accept(c->sock, &addr, &addrlen);
1169 if (c->single_connection) {
1170 debug2("single_connection: closing X11 listener.");
1171 channel_close_fd(&c->sock);
1175 error("accept: %.100s", strerror(errno));
1178 set_nodelay(newsock);
1179 remote_ipaddr = get_peer_ipaddr(newsock);
1180 remote_port = get_peer_port(newsock);
1181 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1182 remote_ipaddr, remote_port);
1184 nc = channel_new("accepted x11 socket",
1185 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1186 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1188 packet_start(SSH2_MSG_CHANNEL_OPEN);
1189 packet_put_cstring("x11");
1190 packet_put_int(nc->self);
1191 packet_put_int(nc->local_window_max);
1192 packet_put_int(nc->local_maxpacket);
1193 /* originator ipaddr and port */
1194 packet_put_cstring(remote_ipaddr);
1195 if (datafellows & SSH_BUG_X11FWD) {
1196 debug2("ssh2 x11 bug compat mode");
1198 packet_put_int(remote_port);
1202 packet_start(SSH_SMSG_X11_OPEN);
1203 packet_put_int(nc->self);
1204 if (packet_get_protocol_flags() &
1205 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1206 packet_put_cstring(buf);
1209 xfree(remote_ipaddr);
1214 port_open_helper(Channel *c, char *rtype)
1218 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1219 int remote_port = get_peer_port(c->sock);
1221 direct = (strcmp(rtype, "direct-tcpip") == 0);
1223 snprintf(buf, sizeof buf,
1224 "%s: listening port %d for %.100s port %d, "
1225 "connect from %.200s port %d",
1226 rtype, c->listening_port, c->path, c->host_port,
1227 remote_ipaddr, remote_port);
1229 xfree(c->remote_name);
1230 c->remote_name = xstrdup(buf);
1233 packet_start(SSH2_MSG_CHANNEL_OPEN);
1234 packet_put_cstring(rtype);
1235 packet_put_int(c->self);
1236 packet_put_int(c->local_window_max);
1237 packet_put_int(c->local_maxpacket);
1239 /* target host, port */
1240 packet_put_cstring(c->path);
1241 packet_put_int(c->host_port);
1243 /* listen address, port */
1244 packet_put_cstring(c->path);
1245 packet_put_int(c->listening_port);
1247 /* originator host and port */
1248 packet_put_cstring(remote_ipaddr);
1249 packet_put_int((u_int)remote_port);
1252 packet_start(SSH_MSG_PORT_OPEN);
1253 packet_put_int(c->self);
1254 packet_put_cstring(c->path);
1255 packet_put_int(c->host_port);
1256 if (packet_get_protocol_flags() &
1257 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1258 packet_put_cstring(c->remote_name);
1261 xfree(remote_ipaddr);
1265 channel_set_reuseaddr(int fd)
1270 * Set socket options.
1271 * Allow local port reuse in TIME_WAIT.
1273 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1274 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1278 * This socket is listening for connections to a forwarded TCP/IP port.
1281 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1284 struct sockaddr addr;
1285 int newsock, nextstate;
1289 if (FD_ISSET(c->sock, readset)) {
1290 debug("Connection to port %d forwarding "
1291 "to %.100s port %d requested.",
1292 c->listening_port, c->path, c->host_port);
1294 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1295 nextstate = SSH_CHANNEL_OPENING;
1296 rtype = "forwarded-tcpip";
1298 if (c->host_port == 0) {
1299 nextstate = SSH_CHANNEL_DYNAMIC;
1300 rtype = "dynamic-tcpip";
1302 nextstate = SSH_CHANNEL_OPENING;
1303 rtype = "direct-tcpip";
1307 addrlen = sizeof(addr);
1308 newsock = accept(c->sock, &addr, &addrlen);
1310 error("accept: %.100s", strerror(errno));
1313 set_nodelay(newsock);
1314 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1315 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1316 nc->listening_port = c->listening_port;
1317 nc->host_port = c->host_port;
1318 strlcpy(nc->path, c->path, sizeof(nc->path));
1320 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1322 * do not call the channel_post handler until
1323 * this flag has been reset by a pre-handler.
1324 * otherwise the FD_ISSET calls might overflow
1328 port_open_helper(nc, rtype);
1334 * This is the authentication agent socket listening for connections from
1338 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1342 struct sockaddr addr;
1345 if (FD_ISSET(c->sock, readset)) {
1346 addrlen = sizeof(addr);
1347 newsock = accept(c->sock, &addr, &addrlen);
1349 error("accept from auth socket: %.100s", strerror(errno));
1352 nc = channel_new("accepted auth socket",
1353 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1354 c->local_window_max, c->local_maxpacket,
1355 0, "accepted auth socket", 1);
1357 packet_start(SSH2_MSG_CHANNEL_OPEN);
1358 packet_put_cstring("auth-agent@openssh.com");
1359 packet_put_int(nc->self);
1360 packet_put_int(c->local_window_max);
1361 packet_put_int(c->local_maxpacket);
1363 packet_start(SSH_SMSG_AGENT_OPEN);
1364 packet_put_int(nc->self);
1371 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1374 socklen_t sz = sizeof(err);
1376 if (FD_ISSET(c->sock, writeset)) {
1377 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1379 error("getsockopt SO_ERROR failed");
1382 debug("channel %d: connected", c->self);
1383 c->type = SSH_CHANNEL_OPEN;
1385 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1386 packet_put_int(c->remote_id);
1387 packet_put_int(c->self);
1388 packet_put_int(c->local_window);
1389 packet_put_int(c->local_maxpacket);
1391 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1392 packet_put_int(c->remote_id);
1393 packet_put_int(c->self);
1396 debug("channel %d: not connected: %s",
1397 c->self, strerror(err));
1399 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1400 packet_put_int(c->remote_id);
1401 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1402 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1403 packet_put_cstring(strerror(err));
1404 packet_put_cstring("");
1407 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1408 packet_put_int(c->remote_id);
1417 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1419 char buf[CHAN_RBUF];
1423 FD_ISSET(c->rfd, readset)) {
1424 len = read(c->rfd, buf, sizeof(buf));
1425 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1428 debug2("channel %d: read<=0 rfd %d len %d",
1429 c->self, c->rfd, len);
1430 if (c->type != SSH_CHANNEL_OPEN) {
1431 debug2("channel %d: not open", c->self);
1434 } else if (compat13) {
1435 buffer_clear(&c->output);
1436 c->type = SSH_CHANNEL_INPUT_DRAINING;
1437 debug2("channel %d: input draining.", c->self);
1439 chan_read_failed(c);
1443 if (c->input_filter != NULL) {
1444 if (c->input_filter(c, buf, len) == -1) {
1445 debug2("channel %d: filter stops", c->self);
1446 chan_read_failed(c);
1448 } else if (c->datagram) {
1449 buffer_put_string(&c->input, buf, len);
1451 buffer_append(&c->input, buf, len);
1457 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1460 u_char *data = NULL, *buf;
1464 /* Send buffered output data to the socket. */
1466 FD_ISSET(c->wfd, writeset) &&
1467 buffer_len(&c->output) > 0) {
1468 if (c->output_filter != NULL) {
1469 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1470 debug2("channel %d: filter stops", c->self);
1471 if (c->type != SSH_CHANNEL_OPEN)
1474 chan_write_failed(c);
1477 } else if (c->datagram) {
1478 buf = data = buffer_get_string(&c->output, &dlen);
1480 buf = data = buffer_ptr(&c->output);
1481 dlen = buffer_len(&c->output);
1485 /* ignore truncated writes, datagrams might get lost */
1486 c->local_consumed += dlen + 4;
1487 len = write(c->wfd, buf, dlen);
1489 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1492 if (c->type != SSH_CHANNEL_OPEN)
1495 chan_write_failed(c);
1501 /* XXX: Later AIX versions can't push as much data to tty */
1502 if (compat20 && c->wfd_isatty)
1503 dlen = MIN(dlen, 8*1024);
1506 len = write(c->wfd, buf, dlen);
1507 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1510 if (c->type != SSH_CHANNEL_OPEN) {
1511 debug2("channel %d: not open", c->self);
1514 } else if (compat13) {
1515 buffer_clear(&c->output);
1516 debug2("channel %d: input draining.", c->self);
1517 c->type = SSH_CHANNEL_INPUT_DRAINING;
1519 chan_write_failed(c);
1523 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1524 if (tcgetattr(c->wfd, &tio) == 0 &&
1525 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1527 * Simulate echo to reduce the impact of
1528 * traffic analysis. We need to match the
1529 * size of a SSH2_MSG_CHANNEL_DATA message
1530 * (4 byte channel id + buf)
1532 packet_send_ignore(4 + len);
1536 buffer_consume(&c->output, len);
1537 if (compat20 && len > 0) {
1538 c->local_consumed += len;
1544 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1546 char buf[CHAN_RBUF];
1549 /** XXX handle drain efd, too */
1551 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1552 FD_ISSET(c->efd, writeset) &&
1553 buffer_len(&c->extended) > 0) {
1554 len = write(c->efd, buffer_ptr(&c->extended),
1555 buffer_len(&c->extended));
1556 debug2("channel %d: written %d to efd %d",
1557 c->self, len, c->efd);
1558 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1561 debug2("channel %d: closing write-efd %d",
1563 channel_close_fd(&c->efd);
1565 buffer_consume(&c->extended, len);
1566 c->local_consumed += len;
1568 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1569 FD_ISSET(c->efd, readset)) {
1570 len = read(c->efd, buf, sizeof(buf));
1571 debug2("channel %d: read %d from efd %d",
1572 c->self, len, c->efd);
1573 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1576 debug2("channel %d: closing read-efd %d",
1578 channel_close_fd(&c->efd);
1580 buffer_append(&c->extended, buf, len);
1587 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1592 /* Monitor control fd to detect if the slave client exits */
1593 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1594 len = read(c->ctl_fd, buf, sizeof(buf));
1595 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1598 debug2("channel %d: ctl read<=0", c->self);
1599 if (c->type != SSH_CHANNEL_OPEN) {
1600 debug2("channel %d: not open", c->self);
1604 chan_read_failed(c);
1605 chan_write_failed(c);
1609 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. */
1826 channel_output_poll(void)
1831 for (i = 0; i < channels_alloc; i++) {
1837 * We are only interested in channels that can have buffered
1841 if (c->type != SSH_CHANNEL_OPEN &&
1842 c->type != SSH_CHANNEL_INPUT_DRAINING)
1845 if (c->type != SSH_CHANNEL_OPEN)
1849 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1850 /* XXX is this true? */
1851 debug3("channel %d: will not send data after close", c->self);
1855 /* Get the amount of buffered data for this channel. */
1856 if ((c->istate == CHAN_INPUT_OPEN ||
1857 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1858 (len = buffer_len(&c->input)) > 0) {
1864 data = buffer_get_string(&c->input,
1866 packet_start(SSH2_MSG_CHANNEL_DATA);
1867 packet_put_int(c->remote_id);
1868 packet_put_string(data, dlen);
1870 c->remote_window -= dlen + 4;
1876 * Send some data for the other side over the secure
1880 if (len > c->remote_window)
1881 len = c->remote_window;
1882 if (len > c->remote_maxpacket)
1883 len = c->remote_maxpacket;
1885 if (packet_is_interactive()) {
1889 /* Keep the packets at reasonable size. */
1890 if (len > packet_get_maxsize()/2)
1891 len = packet_get_maxsize()/2;
1895 packet_start(compat20 ?
1896 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1897 packet_put_int(c->remote_id);
1898 packet_put_string(buffer_ptr(&c->input), len);
1900 buffer_consume(&c->input, len);
1901 c->remote_window -= len;
1903 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1905 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1907 * input-buffer is empty and read-socket shutdown:
1908 * tell peer, that we will not send more data: send IEOF.
1909 * hack for extended data: delay EOF if EFD still in use.
1911 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1912 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1913 c->self, c->efd, buffer_len(&c->extended));
1917 /* Send extended data, i.e. stderr */
1919 !(c->flags & CHAN_EOF_SENT) &&
1920 c->remote_window > 0 &&
1921 (len = buffer_len(&c->extended)) > 0 &&
1922 c->extended_usage == CHAN_EXTENDED_READ) {
1923 debug2("channel %d: rwin %u elen %u euse %d",
1924 c->self, c->remote_window, buffer_len(&c->extended),
1926 if (len > c->remote_window)
1927 len = c->remote_window;
1928 if (len > c->remote_maxpacket)
1929 len = c->remote_maxpacket;
1930 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1931 packet_put_int(c->remote_id);
1932 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1933 packet_put_string(buffer_ptr(&c->extended), len);
1935 buffer_consume(&c->extended, len);
1936 c->remote_window -= len;
1937 debug2("channel %d: sent ext data %d", c->self, len);
1943 /* -- protocol input */
1946 channel_input_data(int type, u_int32_t seq, void *ctxt)
1953 /* Get the channel number and verify it. */
1954 id = packet_get_int();
1955 c = channel_lookup(id);
1957 packet_disconnect("Received data for nonexistent channel %d.", id);
1959 /* Ignore any data for non-open channels (might happen on close) */
1960 if (c->type != SSH_CHANNEL_OPEN &&
1961 c->type != SSH_CHANNEL_X11_OPEN)
1965 data = packet_get_string(&data_len);
1968 * Ignore data for protocol > 1.3 if output end is no longer open.
1969 * For protocol 2 the sending side is reducing its window as it sends
1970 * data, so we must 'fake' consumption of the data in order to ensure
1971 * that window updates are sent back. Otherwise the connection might
1974 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1976 c->local_window -= data_len;
1977 c->local_consumed += data_len;
1984 if (data_len > c->local_maxpacket) {
1985 logit("channel %d: rcvd big packet %d, maxpack %d",
1986 c->self, data_len, c->local_maxpacket);
1988 if (data_len > c->local_window) {
1989 logit("channel %d: rcvd too much data %d, win %d",
1990 c->self, data_len, c->local_window);
1994 c->local_window -= data_len;
1998 buffer_put_string(&c->output, data, data_len);
2000 buffer_append(&c->output, data, data_len);
2005 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2009 u_int data_len, tcode;
2012 /* Get the channel number and verify it. */
2013 id = packet_get_int();
2014 c = channel_lookup(id);
2017 packet_disconnect("Received extended_data for bad channel %d.", id);
2018 if (c->type != SSH_CHANNEL_OPEN) {
2019 logit("channel %d: ext data for non open", id);
2022 if (c->flags & CHAN_EOF_RCVD) {
2023 if (datafellows & SSH_BUG_EXTEOF)
2024 debug("channel %d: accepting ext data after eof", id);
2026 packet_disconnect("Received extended_data after EOF "
2027 "on channel %d.", id);
2029 tcode = packet_get_int();
2031 c->extended_usage != CHAN_EXTENDED_WRITE ||
2032 tcode != SSH2_EXTENDED_DATA_STDERR) {
2033 logit("channel %d: bad ext data", c->self);
2036 data = packet_get_string(&data_len);
2038 if (data_len > c->local_window) {
2039 logit("channel %d: rcvd too much extended_data %d, win %d",
2040 c->self, data_len, c->local_window);
2044 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2045 c->local_window -= data_len;
2046 buffer_append(&c->extended, data, data_len);
2051 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2056 id = packet_get_int();
2058 c = channel_lookup(id);
2060 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2063 /* XXX force input close */
2064 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2065 debug("channel %d: FORCE input drain", c->self);
2066 c->istate = CHAN_INPUT_WAIT_DRAIN;
2067 if (buffer_len(&c->input) == 0)
2074 channel_input_close(int type, u_int32_t seq, void *ctxt)
2079 id = packet_get_int();
2081 c = channel_lookup(id);
2083 packet_disconnect("Received close for nonexistent channel %d.", id);
2086 * Send a confirmation that we have closed the channel and no more
2087 * data is coming for it.
2089 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2090 packet_put_int(c->remote_id);
2094 * If the channel is in closed state, we have sent a close request,
2095 * and the other side will eventually respond with a confirmation.
2096 * Thus, we cannot free the channel here, because then there would be
2097 * no-one to receive the confirmation. The channel gets freed when
2098 * the confirmation arrives.
2100 if (c->type != SSH_CHANNEL_CLOSED) {
2102 * Not a closed channel - mark it as draining, which will
2103 * cause it to be freed later.
2105 buffer_clear(&c->input);
2106 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2110 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2112 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2114 int id = packet_get_int();
2115 Channel *c = channel_lookup(id);
2119 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2120 chan_rcvd_oclose(c);
2124 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2126 int id = packet_get_int();
2127 Channel *c = channel_lookup(id);
2131 packet_disconnect("Received close confirmation for "
2132 "out-of-range channel %d.", id);
2133 if (c->type != SSH_CHANNEL_CLOSED)
2134 packet_disconnect("Received close confirmation for "
2135 "non-closed channel %d (type %d).", id, c->type);
2140 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2145 id = packet_get_int();
2146 c = channel_lookup(id);
2148 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2149 packet_disconnect("Received open confirmation for "
2150 "non-opening channel %d.", id);
2151 remote_id = packet_get_int();
2152 /* Record the remote channel number and mark that the channel is now open. */
2153 c->remote_id = remote_id;
2154 c->type = SSH_CHANNEL_OPEN;
2157 c->remote_window = packet_get_int();
2158 c->remote_maxpacket = packet_get_int();
2160 debug2("callback start");
2161 c->confirm(c->self, c->confirm_ctx);
2162 debug2("callback done");
2164 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2165 c->remote_window, c->remote_maxpacket);
2171 reason2txt(int reason)
2174 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2175 return "administratively prohibited";
2176 case SSH2_OPEN_CONNECT_FAILED:
2177 return "connect failed";
2178 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2179 return "unknown channel type";
2180 case SSH2_OPEN_RESOURCE_SHORTAGE:
2181 return "resource shortage";
2183 return "unknown reason";
2187 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2190 char *msg = NULL, *lang = NULL;
2193 id = packet_get_int();
2194 c = channel_lookup(id);
2196 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2197 packet_disconnect("Received open failure for "
2198 "non-opening channel %d.", id);
2200 reason = packet_get_int();
2201 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2202 msg = packet_get_string(NULL);
2203 lang = packet_get_string(NULL);
2205 logit("channel %d: open failed: %s%s%s", id,
2206 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2213 /* Free the channel. This will also close the socket. */
2218 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2227 /* Get the channel number and verify it. */
2228 id = packet_get_int();
2229 c = channel_lookup(id);
2232 logit("Received window adjust for non-open channel %d.", id);
2235 adjust = packet_get_int();
2237 debug2("channel %d: rcvd adjust %u", id, adjust);
2238 c->remote_window += adjust;
2242 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2246 char *host, *originator_string;
2247 int remote_id, sock = -1;
2249 remote_id = packet_get_int();
2250 host = packet_get_string(NULL);
2251 host_port = packet_get_int();
2253 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2254 originator_string = packet_get_string(NULL);
2256 originator_string = xstrdup("unknown (remote did not supply name)");
2259 sock = channel_connect_to(host, host_port);
2261 c = channel_new("connected socket",
2262 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2263 originator_string, 1);
2264 c->remote_id = remote_id;
2266 xfree(originator_string);
2268 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2269 packet_put_int(remote_id);
2276 /* -- tcp forwarding */
2279 channel_set_af(int af)
2285 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2286 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2289 int sock, r, success = 0, wildcard = 0, is_client;
2290 struct addrinfo hints, *ai, *aitop;
2291 const char *host, *addr;
2292 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2294 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2295 listen_addr : host_to_connect;
2296 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2299 error("No forward host name.");
2302 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2303 error("Forward host name too long.");
2308 * Determine whether or not a port forward listens to loopback,
2309 * specified address or wildcard. On the client, a specified bind
2310 * address will always override gateway_ports. On the server, a
2311 * gateway_ports of 1 (``yes'') will override the client's
2312 * specification and force a wildcard bind, whereas a value of 2
2313 * (``clientspecified'') will bind to whatever address the client
2316 * Special-case listen_addrs are:
2318 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2319 * "" (empty string), "*" -> wildcard v4/v6
2320 * "localhost" -> loopback v4/v6
2323 if (listen_addr == NULL) {
2324 /* No address specified: default to gateway_ports setting */
2327 } else if (gateway_ports || is_client) {
2328 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2329 strcmp(listen_addr, "0.0.0.0") == 0) ||
2330 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2331 (!is_client && gateway_ports == 1))
2333 else if (strcmp(listen_addr, "localhost") != 0)
2337 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2338 type, wildcard, (addr == NULL) ? "NULL" : addr);
2341 * getaddrinfo returns a loopback address if the hostname is
2342 * set to NULL and hints.ai_flags is not AI_PASSIVE
2344 memset(&hints, 0, sizeof(hints));
2345 hints.ai_family = IPv4or6;
2346 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2347 hints.ai_socktype = SOCK_STREAM;
2348 snprintf(strport, sizeof strport, "%d", listen_port);
2349 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2351 /* This really shouldn't happen */
2352 packet_disconnect("getaddrinfo: fatal error: %s",
2355 error("channel_setup_fwd_listener: "
2356 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2361 for (ai = aitop; ai; ai = ai->ai_next) {
2362 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2364 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2365 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2366 error("channel_setup_fwd_listener: getnameinfo failed");
2369 /* Create a port to listen for the host. */
2370 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2372 /* this is no error since kernel may not support ipv6 */
2373 verbose("socket: %.100s", strerror(errno));
2377 channel_set_reuseaddr(sock);
2379 debug("Local forwarding listening on %s port %s.", ntop, strport);
2381 /* Bind the socket to the address. */
2382 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2383 /* address can be in use ipv6 address is already bound */
2385 error("bind: %.100s", strerror(errno));
2387 verbose("bind: %.100s", strerror(errno));
2392 /* Start listening for connections on the socket. */
2393 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2394 error("listen: %.100s", strerror(errno));
2398 /* Allocate a channel number for the socket. */
2399 c = channel_new("port listener", type, sock, sock, -1,
2400 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2401 0, "port listener", 1);
2402 strlcpy(c->path, host, sizeof(c->path));
2403 c->host_port = port_to_connect;
2404 c->listening_port = listen_port;
2408 error("channel_setup_fwd_listener: cannot listen to port: %d",
2410 freeaddrinfo(aitop);
2415 channel_cancel_rport_listener(const char *host, u_short port)
2420 for (i = 0; i < channels_alloc; i++) {
2421 Channel *c = channels[i];
2423 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2424 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2425 c->listening_port == port) {
2426 debug2("%s: close channel %d", __func__, i);
2435 /* protocol local port fwd, used by ssh (and sshd in v1) */
2437 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2438 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2440 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2441 listen_host, listen_port, host_to_connect, port_to_connect,
2445 /* protocol v2 remote port fwd, used by sshd */
2447 channel_setup_remote_fwd_listener(const char *listen_address,
2448 u_short listen_port, int gateway_ports)
2450 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2451 listen_address, listen_port, NULL, 0, gateway_ports);
2455 * Initiate forwarding of connections to port "port" on remote host through
2456 * the secure channel to host:port from local side.
2460 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2461 const char *host_to_connect, u_short port_to_connect)
2463 int type, success = 0;
2465 /* Record locally that connection to this host/port is permitted. */
2466 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2467 fatal("channel_request_remote_forwarding: too many forwards");
2469 /* Send the forward request to the remote side. */
2471 const char *address_to_bind;
2472 if (listen_host == NULL)
2473 address_to_bind = "localhost";
2474 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2475 address_to_bind = "";
2477 address_to_bind = listen_host;
2479 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2480 packet_put_cstring("tcpip-forward");
2481 packet_put_char(1); /* boolean: want reply */
2482 packet_put_cstring(address_to_bind);
2483 packet_put_int(listen_port);
2485 packet_write_wait();
2486 /* Assume that server accepts the request */
2489 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2490 packet_put_int(listen_port);
2491 packet_put_cstring(host_to_connect);
2492 packet_put_int(port_to_connect);
2494 packet_write_wait();
2496 /* Wait for response from the remote side. */
2497 type = packet_read();
2499 case SSH_SMSG_SUCCESS:
2502 case SSH_SMSG_FAILURE:
2503 logit("Warning: Server denied remote port forwarding.");
2506 /* Unknown packet */
2507 packet_disconnect("Protocol error for port forward request:"
2508 "received packet type %d.", type);
2512 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2513 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2514 permitted_opens[num_permitted_opens].listen_port = listen_port;
2515 num_permitted_opens++;
2520 * Request cancellation of remote forwarding of connection host:port from
2524 channel_request_rforward_cancel(const char *host, u_short port)
2531 for (i = 0; i < num_permitted_opens; i++) {
2532 if (permitted_opens[i].host_to_connect != NULL &&
2533 permitted_opens[i].listen_port == port)
2536 if (i >= num_permitted_opens) {
2537 debug("%s: requested forward not found", __func__);
2540 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2541 packet_put_cstring("cancel-tcpip-forward");
2543 packet_put_cstring(host == NULL ? "" : host);
2544 packet_put_int(port);
2547 permitted_opens[i].listen_port = 0;
2548 permitted_opens[i].port_to_connect = 0;
2549 xfree(permitted_opens[i].host_to_connect);
2550 permitted_opens[i].host_to_connect = NULL;
2554 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2555 * listening for the port, and sends back a success reply (or disconnect
2556 * message if there was an error). This never returns if there was an error.
2560 channel_input_port_forward_request(int is_root, int gateway_ports)
2562 u_short port, host_port;
2565 /* Get arguments from the packet. */
2566 port = packet_get_int();
2567 hostname = packet_get_string(NULL);
2568 host_port = packet_get_int();
2572 * Check that an unprivileged user is not trying to forward a
2575 if (port < IPPORT_RESERVED && !is_root)
2577 "Requested forwarding of port %d but user is not root.",
2580 packet_disconnect("Dynamic forwarding denied.");
2583 /* Initiate forwarding */
2584 channel_setup_local_fwd_listener(NULL, port, hostname,
2585 host_port, gateway_ports);
2587 /* Free the argument string. */
2592 * Permits opening to any host/port if permitted_opens[] is empty. This is
2593 * usually called by the server, because the user could connect to any port
2594 * anyway, and the server has no way to know but to trust the client anyway.
2597 channel_permit_all_opens(void)
2599 if (num_permitted_opens == 0)
2600 all_opens_permitted = 1;
2604 channel_add_permitted_opens(char *host, int port)
2606 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2607 fatal("channel_request_remote_forwarding: too many forwards");
2608 debug("allow port forwarding to host %s port %d", host, port);
2610 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2611 permitted_opens[num_permitted_opens].port_to_connect = port;
2612 num_permitted_opens++;
2614 all_opens_permitted = 0;
2618 channel_clear_permitted_opens(void)
2622 for (i = 0; i < num_permitted_opens; i++)
2623 if (permitted_opens[i].host_to_connect != NULL)
2624 xfree(permitted_opens[i].host_to_connect);
2625 num_permitted_opens = 0;
2630 /* return socket to remote host, port */
2632 connect_to(const char *host, u_short port)
2634 struct addrinfo hints, *ai, *aitop;
2635 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2639 memset(&hints, 0, sizeof(hints));
2640 hints.ai_family = IPv4or6;
2641 hints.ai_socktype = SOCK_STREAM;
2642 snprintf(strport, sizeof strport, "%d", port);
2643 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2644 error("connect_to %.100s: unknown host (%s)", host,
2645 gai_strerror(gaierr));
2648 for (ai = aitop; ai; ai = ai->ai_next) {
2649 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2651 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2652 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2653 error("connect_to: getnameinfo failed");
2656 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2658 if (ai->ai_next == NULL)
2659 error("socket: %.100s", strerror(errno));
2661 verbose("socket: %.100s", strerror(errno));
2664 if (set_nonblock(sock) == -1)
2665 fatal("%s: set_nonblock(%d)", __func__, sock);
2666 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2667 errno != EINPROGRESS) {
2668 error("connect_to %.100s port %s: %.100s", ntop, strport,
2671 continue; /* fail -- try next */
2673 break; /* success */
2676 freeaddrinfo(aitop);
2678 error("connect_to %.100s port %d: failed.", host, port);
2687 channel_connect_by_listen_address(u_short listen_port)
2691 for (i = 0; i < num_permitted_opens; i++)
2692 if (permitted_opens[i].host_to_connect != NULL &&
2693 permitted_opens[i].listen_port == listen_port)
2695 permitted_opens[i].host_to_connect,
2696 permitted_opens[i].port_to_connect);
2697 error("WARNING: Server requests forwarding for unknown listen_port %d",
2702 /* Check if connecting to that port is permitted and connect. */
2704 channel_connect_to(const char *host, u_short port)
2708 permit = all_opens_permitted;
2710 for (i = 0; i < num_permitted_opens; i++)
2711 if (permitted_opens[i].host_to_connect != NULL &&
2712 permitted_opens[i].port_to_connect == port &&
2713 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2718 logit("Received request to connect to host %.100s port %d, "
2719 "but the request was denied.", host, port);
2722 return connect_to(host, port);
2726 channel_send_window_changes(void)
2731 for (i = 0; i < channels_alloc; i++) {
2732 if (channels[i] == NULL || !channels[i]->client_tty ||
2733 channels[i]->type != SSH_CHANNEL_OPEN)
2735 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2737 channel_request_start(i, "window-change", 0);
2738 packet_put_int(ws.ws_col);
2739 packet_put_int(ws.ws_row);
2740 packet_put_int(ws.ws_xpixel);
2741 packet_put_int(ws.ws_ypixel);
2746 /* -- X11 forwarding */
2749 * Creates an internet domain socket for listening for X11 connections.
2750 * Returns 0 and a suitable display number for the DISPLAY variable
2751 * stored in display_numberp , or -1 if an error occurs.
2754 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2755 int single_connection, u_int *display_numberp, int **chanids)
2758 int display_number, sock;
2760 struct addrinfo hints, *ai, *aitop;
2761 char strport[NI_MAXSERV];
2762 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2764 if (chanids == NULL)
2767 for (display_number = x11_display_offset;
2768 display_number < MAX_DISPLAYS;
2770 port = 6000 + display_number;
2771 memset(&hints, 0, sizeof(hints));
2772 hints.ai_family = IPv4or6;
2773 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2774 hints.ai_socktype = SOCK_STREAM;
2775 snprintf(strport, sizeof strport, "%d", port);
2776 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2777 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2780 for (ai = aitop; ai; ai = ai->ai_next) {
2781 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2783 sock = socket(ai->ai_family, ai->ai_socktype,
2786 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2787 error("socket: %.100s", strerror(errno));
2788 freeaddrinfo(aitop);
2791 debug("x11_create_display_inet: Socket family %d not supported",
2797 if (ai->ai_family == AF_INET6) {
2799 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2800 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2803 channel_set_reuseaddr(sock);
2804 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2805 debug2("bind port %d: %.100s", port, strerror(errno));
2811 for (n = 0; n < num_socks; n++) {
2817 socks[num_socks++] = sock;
2818 #ifndef DONT_TRY_OTHER_AF
2819 if (num_socks == NUM_SOCKS)
2822 if (x11_use_localhost) {
2823 if (num_socks == NUM_SOCKS)
2830 freeaddrinfo(aitop);
2834 if (display_number >= MAX_DISPLAYS) {
2835 error("Failed to allocate internet-domain X11 display socket.");
2838 /* Start listening for connections on the socket. */
2839 for (n = 0; n < num_socks; n++) {
2841 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2842 error("listen: %.100s", strerror(errno));
2848 /* Allocate a channel for each socket. */
2849 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
2850 for (n = 0; n < num_socks; n++) {
2852 nc = channel_new("x11 listener",
2853 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2854 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2855 0, "X11 inet listener", 1);
2856 nc->single_connection = single_connection;
2857 (*chanids)[n] = nc->self;
2861 /* Return the display number for the DISPLAY environment variable. */
2862 *display_numberp = display_number;
2867 connect_local_xsocket(u_int dnr)
2870 struct sockaddr_un addr;
2872 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2874 error("socket: %.100s", strerror(errno));
2875 memset(&addr, 0, sizeof(addr));
2876 addr.sun_family = AF_UNIX;
2877 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2878 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2881 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2886 x11_connect_display(void)
2888 int display_number, sock = 0;
2889 const char *display;
2890 char buf[1024], *cp;
2891 struct addrinfo hints, *ai, *aitop;
2892 char strport[NI_MAXSERV];
2895 /* Try to open a socket for the local X server. */
2896 display = getenv("DISPLAY");
2898 error("DISPLAY not set.");
2902 * Now we decode the value of the DISPLAY variable and make a
2903 * connection to the real X server.
2907 * Check if it is a unix domain socket. Unix domain displays are in
2908 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2910 if (strncmp(display, "unix:", 5) == 0 ||
2911 display[0] == ':') {
2912 /* Connect to the unix domain socket. */
2913 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2914 error("Could not parse display number from DISPLAY: %.100s",
2918 /* Create a socket. */
2919 sock = connect_local_xsocket(display_number);
2923 /* OK, we now have a connection to the display. */
2927 * Connect to an inet socket. The DISPLAY value is supposedly
2928 * hostname:d[.s], where hostname may also be numeric IP address.
2930 strlcpy(buf, display, sizeof(buf));
2931 cp = strchr(buf, ':');
2933 error("Could not find ':' in DISPLAY: %.100s", display);
2937 /* buf now contains the host name. But first we parse the display number. */
2938 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2939 error("Could not parse display number from DISPLAY: %.100s",
2944 /* Look up the host address */
2945 memset(&hints, 0, sizeof(hints));
2946 hints.ai_family = IPv4or6;
2947 hints.ai_socktype = SOCK_STREAM;
2948 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2949 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2950 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2953 for (ai = aitop; ai; ai = ai->ai_next) {
2954 /* Create a socket. */
2955 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2957 debug2("socket: %.100s", strerror(errno));
2960 /* Connect it to the display. */
2961 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2962 debug2("connect %.100s port %d: %.100s", buf,
2963 6000 + display_number, strerror(errno));
2970 freeaddrinfo(aitop);
2972 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2981 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2982 * the remote channel number. We should do whatever we want, and respond
2983 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2987 x11_input_open(int type, u_int32_t seq, void *ctxt)
2990 int remote_id, sock = 0;
2993 debug("Received X11 open request.");
2995 remote_id = packet_get_int();
2997 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2998 remote_host = packet_get_string(NULL);
3000 remote_host = xstrdup("unknown (remote did not supply name)");
3004 /* Obtain a connection to the real X display. */
3005 sock = x11_connect_display();
3007 /* Allocate a channel for this connection. */
3008 c = channel_new("connected x11 socket",
3009 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3011 c->remote_id = remote_id;
3016 /* Send refusal to the remote host. */
3017 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3018 packet_put_int(remote_id);
3020 /* Send a confirmation to the remote host. */
3021 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3022 packet_put_int(remote_id);
3023 packet_put_int(c->self);
3028 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3030 deny_input_open(int type, u_int32_t seq, void *ctxt)
3032 int rchan = packet_get_int();
3035 case SSH_SMSG_AGENT_OPEN:
3036 error("Warning: ssh server tried agent forwarding.");
3038 case SSH_SMSG_X11_OPEN:
3039 error("Warning: ssh server tried X11 forwarding.");
3042 error("deny_input_open: type %d", type);
3045 error("Warning: this is probably a break-in attempt by a malicious server.");
3046 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3047 packet_put_int(rchan);
3052 * Requests forwarding of X11 connections, generates fake authentication
3053 * data, and enables authentication spoofing.
3054 * This should be called in the client only.
3057 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3058 const char *proto, const char *data)
3060 u_int data_len = (u_int) strlen(data) / 2;
3067 if (x11_saved_display == NULL)
3068 x11_saved_display = xstrdup(disp);
3069 else if (strcmp(disp, x11_saved_display) != 0) {
3070 error("x11_request_forwarding_with_spoofing: different "
3071 "$DISPLAY already forwarded");
3077 cp = strchr(disp, ':');
3079 cp = strchr(cp, '.');
3081 screen_number = atoi(cp + 1);
3085 if (x11_saved_proto == NULL) {
3086 /* Save protocol name. */
3087 x11_saved_proto = xstrdup(proto);
3089 * Extract real authentication data and generate fake data
3090 * of the same length.
3092 x11_saved_data = xmalloc(data_len);
3093 x11_fake_data = xmalloc(data_len);
3094 for (i = 0; i < data_len; i++) {
3095 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3096 fatal("x11_request_forwarding: bad "
3097 "authentication data: %.100s", data);
3100 x11_saved_data[i] = value;
3101 x11_fake_data[i] = rnd & 0xff;
3104 x11_saved_data_len = data_len;
3105 x11_fake_data_len = data_len;
3108 /* Convert the fake data into hex. */
3109 new_data = tohex(x11_fake_data, data_len);
3111 /* Send the request packet. */
3113 channel_request_start(client_session_id, "x11-req", 0);
3114 packet_put_char(0); /* XXX bool single connection */
3116 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3118 packet_put_cstring(proto);
3119 packet_put_cstring(new_data);
3120 packet_put_int(screen_number);
3122 packet_write_wait();
3127 /* -- agent forwarding */
3129 /* Sends a message to the server to request authentication fd forwarding. */
3132 auth_request_forwarding(void)
3134 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3136 packet_write_wait();