1 /* $OpenBSD: channels.c,v 1.273 2008/04/02 21:36:51 markus Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * This file contains functions for generic socket connection forwarding.
7 * There is also code for initiating connection forwarding for X11 connections,
8 * arbitrary tcp/ip connections, and the authentication agent connection.
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44 #include <sys/types.h>
45 #include <sys/ioctl.h>
47 #include <sys/socket.h>
48 #ifdef HAVE_SYS_TIME_H
49 # include <sys/time.h>
52 #include <netinet/in.h>
53 #include <arpa/inet.h>
77 #include "pathnames.h"
82 * Pointer to an array containing all allocated channels. The array is
83 * dynamically extended as needed.
85 static Channel **channels = NULL;
88 * Size of the channel array. All slots of the array must always be
89 * initialized (at least the type field); unused slots set to NULL
91 static u_int channels_alloc = 0;
94 * Maximum file descriptor value used in any of the channels. This is
95 * updated in channel_new.
97 static int channel_max_fd = 0;
100 /* -- tcp forwarding */
103 * Data structure for storing which hosts are permitted for forward requests.
104 * The local sides of any remote forwards are stored in this array to prevent
105 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
106 * network (which might be behind a firewall).
109 char *host_to_connect; /* Connect to 'host'. */
110 u_short port_to_connect; /* Connect to 'port'. */
111 u_short listen_port; /* Remote side should listen port number. */
114 /* List of all permitted host/port pairs to connect by the user. */
115 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
117 /* List of all permitted host/port pairs to connect by the admin. */
118 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
120 /* Number of permitted host/port pairs in the array permitted by the user. */
121 static int num_permitted_opens = 0;
123 /* Number of permitted host/port pair in the array permitted by the admin. */
124 static int num_adm_permitted_opens = 0;
127 * If this is true, all opens are permitted. This is the case on the server
128 * on which we have to trust the client anyway, and the user could do
129 * anything after logging in anyway.
131 static int all_opens_permitted = 0;
134 /* -- X11 forwarding */
136 /* Maximum number of fake X11 displays to try. */
137 #define MAX_DISPLAYS 1000
139 /* Saved X11 local (client) display. */
140 static char *x11_saved_display = NULL;
142 /* Saved X11 authentication protocol name. */
143 static char *x11_saved_proto = NULL;
145 /* Saved X11 authentication data. This is the real data. */
146 static char *x11_saved_data = NULL;
147 static u_int x11_saved_data_len = 0;
150 * Fake X11 authentication data. This is what the server will be sending us;
151 * we should replace any occurrences of this by the real data.
153 static u_char *x11_fake_data = NULL;
154 static u_int x11_fake_data_len;
157 /* -- agent forwarding */
161 /* AF_UNSPEC or AF_INET or AF_INET6 */
162 static int IPv4or6 = AF_UNSPEC;
165 static void port_open_helper(Channel *c, char *rtype);
167 /* -- channel core */
170 channel_by_id(int id)
174 if (id < 0 || (u_int)id >= channels_alloc) {
175 logit("channel_by_id: %d: bad id", id);
180 logit("channel_by_id: %d: bad id: channel free", id);
187 * Returns the channel if it is allowed to receive protocol messages.
188 * Private channels, like listening sockets, may not receive messages.
191 channel_lookup(int id)
195 if ((c = channel_by_id(id)) == NULL)
199 case SSH_CHANNEL_X11_OPEN:
200 case SSH_CHANNEL_LARVAL:
201 case SSH_CHANNEL_CONNECTING:
202 case SSH_CHANNEL_DYNAMIC:
203 case SSH_CHANNEL_OPENING:
204 case SSH_CHANNEL_OPEN:
205 case SSH_CHANNEL_INPUT_DRAINING:
206 case SSH_CHANNEL_OUTPUT_DRAINING:
209 logit("Non-public channel %d, type %d.", id, c->type);
214 * Register filedescriptors for a channel, used when allocating a channel or
215 * when the channel consumer/producer is ready, e.g. shell exec'd
218 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
219 int extusage, int nonblock)
221 /* Update the maximum file descriptor value. */
222 channel_max_fd = MAX(channel_max_fd, rfd);
223 channel_max_fd = MAX(channel_max_fd, wfd);
224 channel_max_fd = MAX(channel_max_fd, efd);
226 /* XXX set close-on-exec -markus */
230 c->sock = (rfd == wfd) ? rfd : -1;
231 c->ctl_fd = -1; /* XXX: set elsewhere */
233 c->extended_usage = extusage;
235 /* XXX ugly hack: nonblock is only set by the server */
236 if (nonblock && isatty(c->rfd)) {
237 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
239 if (!isatty(c->wfd)) {
240 error("channel %d: wfd %d is not a tty?",
246 c->wfd_isatty = isatty(c->wfd);
248 /* enable nonblocking mode */
260 * Allocate a new channel object and set its type and socket. This will cause
261 * remote_name to be freed.
264 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
265 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
271 /* Do initial allocation if this is the first call. */
272 if (channels_alloc == 0) {
274 channels = xcalloc(channels_alloc, sizeof(Channel *));
275 for (i = 0; i < channels_alloc; i++)
278 /* Try to find a free slot where to put the new channel. */
279 for (found = -1, i = 0; i < channels_alloc; i++)
280 if (channels[i] == NULL) {
281 /* Found a free slot. */
286 /* There are no free slots. Take last+1 slot and expand the array. */
287 found = channels_alloc;
288 if (channels_alloc > 10000)
289 fatal("channel_new: internal error: channels_alloc %d "
290 "too big.", channels_alloc);
291 channels = xrealloc(channels, channels_alloc + 10,
293 channels_alloc += 10;
294 debug2("channel: expanding %d", channels_alloc);
295 for (i = found; i < channels_alloc; i++)
298 /* Initialize and return new channel. */
299 c = channels[found] = xcalloc(1, sizeof(Channel));
300 buffer_init(&c->input);
301 buffer_init(&c->output);
302 buffer_init(&c->extended);
303 c->ostate = CHAN_OUTPUT_OPEN;
304 c->istate = CHAN_INPUT_OPEN;
306 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
310 c->local_window = window;
311 c->local_window_max = window;
312 c->local_consumed = 0;
313 c->local_maxpacket = maxpack;
314 c->dynamic_window = 0;
316 c->remote_name = xstrdup(remote_name);
317 c->remote_window = 0;
318 c->remote_maxpacket = 0;
320 c->single_connection = 0;
321 c->detach_user = NULL;
324 c->confirm_ctx = NULL;
325 c->input_filter = NULL;
326 c->output_filter = NULL;
327 debug("channel %d: new [%s]", found, remote_name);
332 channel_find_maxfd(void)
338 for (i = 0; i < channels_alloc; i++) {
341 max = MAX(max, c->rfd);
342 max = MAX(max, c->wfd);
343 max = MAX(max, c->efd);
350 channel_close_fd(int *fdp)
352 int ret = 0, fd = *fdp;
357 if (fd == channel_max_fd)
358 channel_max_fd = channel_find_maxfd();
363 /* Close all channel fd/socket. */
365 channel_close_fds(Channel *c)
367 debug3("channel %d: close_fds r %d w %d e %d c %d",
368 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
370 channel_close_fd(&c->sock);
371 channel_close_fd(&c->ctl_fd);
372 channel_close_fd(&c->rfd);
373 channel_close_fd(&c->wfd);
374 channel_close_fd(&c->efd);
377 /* Free the channel and close its fd/socket. */
379 channel_free(Channel *c)
384 for (n = 0, i = 0; i < channels_alloc; i++)
387 debug("channel %d: free: %s, nchannels %u", c->self,
388 c->remote_name ? c->remote_name : "???", n);
390 s = channel_open_message();
391 debug3("channel %d: status: %s", c->self, s);
395 shutdown(c->sock, SHUT_RDWR);
397 shutdown(c->ctl_fd, SHUT_RDWR);
398 channel_close_fds(c);
399 buffer_free(&c->input);
400 buffer_free(&c->output);
401 buffer_free(&c->extended);
402 if (c->remote_name) {
403 xfree(c->remote_name);
404 c->remote_name = NULL;
406 channels[c->self] = NULL;
411 channel_free_all(void)
415 for (i = 0; i < channels_alloc; i++)
416 if (channels[i] != NULL)
417 channel_free(channels[i]);
421 * Closes the sockets/fds of all channels. This is used to close extra file
422 * descriptors after a fork.
425 channel_close_all(void)
429 for (i = 0; i < channels_alloc; i++)
430 if (channels[i] != NULL)
431 channel_close_fds(channels[i]);
435 * Stop listening to channels.
438 channel_stop_listening(void)
443 for (i = 0; i < channels_alloc; i++) {
447 case SSH_CHANNEL_AUTH_SOCKET:
448 case SSH_CHANNEL_PORT_LISTENER:
449 case SSH_CHANNEL_RPORT_LISTENER:
450 case SSH_CHANNEL_X11_LISTENER:
451 channel_close_fd(&c->sock);
460 * Returns true if no channel has too much buffered data, and false if one or
461 * more channel is overfull.
464 channel_not_very_much_buffered_data(void)
469 for (i = 0; i < channels_alloc; i++) {
471 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
474 buffer_len(&c->input) > packet_get_maxsize()) {
475 debug2("channel %d: big input buffer %d",
476 c->self, buffer_len(&c->input));
480 if (buffer_len(&c->output) > packet_get_maxsize()) {
481 debug2("channel %d: big output buffer %u > %u",
482 c->self, buffer_len(&c->output),
483 packet_get_maxsize());
491 /* Returns true if any channel is still open. */
493 channel_still_open(void)
498 for (i = 0; i < channels_alloc; i++) {
503 case SSH_CHANNEL_X11_LISTENER:
504 case SSH_CHANNEL_PORT_LISTENER:
505 case SSH_CHANNEL_RPORT_LISTENER:
506 case SSH_CHANNEL_CLOSED:
507 case SSH_CHANNEL_AUTH_SOCKET:
508 case SSH_CHANNEL_DYNAMIC:
509 case SSH_CHANNEL_CONNECTING:
510 case SSH_CHANNEL_ZOMBIE:
512 case SSH_CHANNEL_LARVAL:
514 fatal("cannot happen: SSH_CHANNEL_LARVAL");
516 case SSH_CHANNEL_OPENING:
517 case SSH_CHANNEL_OPEN:
518 case SSH_CHANNEL_X11_OPEN:
520 case SSH_CHANNEL_INPUT_DRAINING:
521 case SSH_CHANNEL_OUTPUT_DRAINING:
523 fatal("cannot happen: OUT_DRAIN");
526 fatal("channel_still_open: bad channel type %d", c->type);
533 /* Returns the id of an open channel suitable for keepaliving */
535 channel_find_open(void)
540 for (i = 0; i < channels_alloc; i++) {
542 if (c == NULL || c->remote_id < 0)
545 case SSH_CHANNEL_CLOSED:
546 case SSH_CHANNEL_DYNAMIC:
547 case SSH_CHANNEL_X11_LISTENER:
548 case SSH_CHANNEL_PORT_LISTENER:
549 case SSH_CHANNEL_RPORT_LISTENER:
550 case SSH_CHANNEL_OPENING:
551 case SSH_CHANNEL_CONNECTING:
552 case SSH_CHANNEL_ZOMBIE:
554 case SSH_CHANNEL_LARVAL:
555 case SSH_CHANNEL_AUTH_SOCKET:
556 case SSH_CHANNEL_OPEN:
557 case SSH_CHANNEL_X11_OPEN:
559 case SSH_CHANNEL_INPUT_DRAINING:
560 case SSH_CHANNEL_OUTPUT_DRAINING:
562 fatal("cannot happen: OUT_DRAIN");
565 fatal("channel_find_open: bad channel type %d", c->type);
574 * Returns a message describing the currently open forwarded connections,
575 * suitable for sending to the client. The message contains crlf pairs for
579 channel_open_message(void)
586 buffer_init(&buffer);
587 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
588 buffer_append(&buffer, buf, strlen(buf));
589 for (i = 0; i < channels_alloc; i++) {
594 case SSH_CHANNEL_X11_LISTENER:
595 case SSH_CHANNEL_PORT_LISTENER:
596 case SSH_CHANNEL_RPORT_LISTENER:
597 case SSH_CHANNEL_CLOSED:
598 case SSH_CHANNEL_AUTH_SOCKET:
599 case SSH_CHANNEL_ZOMBIE:
601 case SSH_CHANNEL_LARVAL:
602 case SSH_CHANNEL_OPENING:
603 case SSH_CHANNEL_CONNECTING:
604 case SSH_CHANNEL_DYNAMIC:
605 case SSH_CHANNEL_OPEN:
606 case SSH_CHANNEL_X11_OPEN:
607 case SSH_CHANNEL_INPUT_DRAINING:
608 case SSH_CHANNEL_OUTPUT_DRAINING:
609 snprintf(buf, sizeof buf,
610 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
611 c->self, c->remote_name,
612 c->type, c->remote_id,
613 c->istate, buffer_len(&c->input),
614 c->ostate, buffer_len(&c->output),
615 c->rfd, c->wfd, c->ctl_fd);
616 buffer_append(&buffer, buf, strlen(buf));
619 fatal("channel_open_message: bad channel type %d", c->type);
623 buffer_append(&buffer, "\0", 1);
624 cp = xstrdup(buffer_ptr(&buffer));
625 buffer_free(&buffer);
630 channel_send_open(int id)
632 Channel *c = channel_lookup(id);
635 logit("channel_send_open: %d: bad id", id);
638 debug2("channel %d: send open", id);
639 packet_start(SSH2_MSG_CHANNEL_OPEN);
640 packet_put_cstring(c->ctype);
641 packet_put_int(c->self);
642 packet_put_int(c->local_window);
643 packet_put_int(c->local_maxpacket);
648 channel_request_start(int id, char *service, int wantconfirm)
650 Channel *c = channel_lookup(id);
653 logit("channel_request_start: %d: unknown channel id", id);
656 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
657 packet_start(SSH2_MSG_CHANNEL_REQUEST);
658 packet_put_int(c->remote_id);
659 packet_put_cstring(service);
660 packet_put_char(wantconfirm);
664 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
666 Channel *c = channel_lookup(id);
669 logit("channel_register_comfirm: %d: bad id", id);
673 c->confirm_ctx = ctx;
677 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
679 Channel *c = channel_by_id(id);
682 logit("channel_register_cleanup: %d: bad id", id);
686 c->detach_close = do_close;
690 channel_cancel_cleanup(int id)
692 Channel *c = channel_by_id(id);
695 logit("channel_cancel_cleanup: %d: bad id", id);
698 c->detach_user = NULL;
703 channel_register_filter(int id, channel_infilter_fn *ifn,
704 channel_outfilter_fn *ofn)
706 Channel *c = channel_lookup(id);
709 logit("channel_register_filter: %d: bad id", id);
712 c->input_filter = ifn;
713 c->output_filter = ofn;
717 channel_set_fds(int id, int rfd, int wfd, int efd,
718 int extusage, int nonblock, u_int window_max)
720 Channel *c = channel_lookup(id);
722 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
723 fatal("channel_activate for non-larval channel %d.", id);
724 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
725 c->type = SSH_CHANNEL_OPEN;
726 c->local_window = c->local_window_max = window_max;
727 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
728 packet_put_int(c->remote_id);
729 packet_put_int(c->local_window);
734 * 'channel_pre*' are called just before select() to add any bits relevant to
735 * channels in the select bitmasks.
738 * 'channel_post*': perform any appropriate operations for channels which
739 * have events pending.
741 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
742 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
743 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
747 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
749 FD_SET(c->sock, readset);
754 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
756 debug3("channel %d: waiting for connection", c->self);
757 FD_SET(c->sock, writeset);
761 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
763 if (buffer_len(&c->input) < packet_get_maxsize())
764 FD_SET(c->sock, readset);
765 if (buffer_len(&c->output) > 0)
766 FD_SET(c->sock, writeset);
769 int channel_tcpwinsz () {
770 u_int32_t tcpwinsz = 0;
771 socklen_t optsz = sizeof(tcpwinsz);
774 /* if we aren't on a socket return 128KB*/
775 if(!packet_connection_is_on_socket())
777 ret = getsockopt(packet_get_connection_in(),
778 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
779 /* return no more than 64MB */
780 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN)
781 tcpwinsz = BUFFER_MAX_LEN_HPN;
782 debug2("tcpwinsz: %d for connection: %d", tcpwinsz,
783 packet_get_connection_in());
788 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
790 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
792 /* check buffer limits */
793 if ((!c->tcpwinsz) || (c->dynamic_window > 0))
794 c->tcpwinsz = channel_tcpwinsz();
796 limit = MIN(limit, 2 * c->tcpwinsz);
798 if (c->istate == CHAN_INPUT_OPEN &&
800 buffer_len(&c->input) < limit &&
801 buffer_check_alloc(&c->input, CHAN_RBUF))
802 FD_SET(c->rfd, readset);
803 if (c->ostate == CHAN_OUTPUT_OPEN ||
804 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
805 if (buffer_len(&c->output) > 0) {
806 FD_SET(c->wfd, writeset);
807 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
808 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
809 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
810 c->self, c->efd, buffer_len(&c->extended));
815 /** XXX check close conditions, too */
816 if (compat20 && c->efd != -1) {
817 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
818 buffer_len(&c->extended) > 0)
819 FD_SET(c->efd, writeset);
820 else if (!(c->flags & CHAN_EOF_SENT) &&
821 c->extended_usage == CHAN_EXTENDED_READ &&
822 buffer_len(&c->extended) < c->remote_window)
823 FD_SET(c->efd, readset);
825 /* XXX: What about efd? races? */
826 if (compat20 && c->ctl_fd != -1 &&
827 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
828 FD_SET(c->ctl_fd, readset);
833 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
835 if (buffer_len(&c->input) == 0) {
836 packet_start(SSH_MSG_CHANNEL_CLOSE);
837 packet_put_int(c->remote_id);
839 c->type = SSH_CHANNEL_CLOSED;
840 debug2("channel %d: closing after input drain.", c->self);
846 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
848 if (buffer_len(&c->output) == 0)
851 FD_SET(c->sock, writeset);
855 * This is a special state for X11 authentication spoofing. An opened X11
856 * connection (when authentication spoofing is being done) remains in this
857 * state until the first packet has been completely read. The authentication
858 * data in that packet is then substituted by the real data if it matches the
859 * fake data, and the channel is put into normal mode.
860 * XXX All this happens at the client side.
861 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
864 x11_open_helper(Buffer *b)
867 u_int proto_len, data_len;
869 /* Check if the fixed size part of the packet is in buffer. */
870 if (buffer_len(b) < 12)
873 /* Parse the lengths of variable-length fields. */
875 if (ucp[0] == 0x42) { /* Byte order MSB first. */
876 proto_len = 256 * ucp[6] + ucp[7];
877 data_len = 256 * ucp[8] + ucp[9];
878 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
879 proto_len = ucp[6] + 256 * ucp[7];
880 data_len = ucp[8] + 256 * ucp[9];
882 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
887 /* Check if the whole packet is in buffer. */
889 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
892 /* Check if authentication protocol matches. */
893 if (proto_len != strlen(x11_saved_proto) ||
894 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
895 debug2("X11 connection uses different authentication protocol.");
898 /* Check if authentication data matches our fake data. */
899 if (data_len != x11_fake_data_len ||
900 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
901 x11_fake_data, x11_fake_data_len) != 0) {
902 debug2("X11 auth data does not match fake data.");
905 /* Check fake data length */
906 if (x11_fake_data_len != x11_saved_data_len) {
907 error("X11 fake_data_len %d != saved_data_len %d",
908 x11_fake_data_len, x11_saved_data_len);
912 * Received authentication protocol and data match
913 * our fake data. Substitute the fake data with real
916 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
917 x11_saved_data, x11_saved_data_len);
922 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
924 int ret = x11_open_helper(&c->output);
927 /* Start normal processing for the channel. */
928 c->type = SSH_CHANNEL_OPEN;
929 channel_pre_open_13(c, readset, writeset);
930 } else if (ret == -1) {
932 * We have received an X11 connection that has bad
933 * authentication information.
935 logit("X11 connection rejected because of wrong authentication.");
936 buffer_clear(&c->input);
937 buffer_clear(&c->output);
938 channel_close_fd(&c->sock);
940 c->type = SSH_CHANNEL_CLOSED;
941 packet_start(SSH_MSG_CHANNEL_CLOSE);
942 packet_put_int(c->remote_id);
948 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
950 int ret = x11_open_helper(&c->output);
952 /* c->force_drain = 1; */
955 c->type = SSH_CHANNEL_OPEN;
956 channel_pre_open(c, readset, writeset);
957 } else if (ret == -1) {
958 logit("X11 connection rejected because of wrong authentication.");
959 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
961 buffer_clear(&c->input);
963 buffer_clear(&c->output);
964 /* for proto v1, the peer will send an IEOF */
966 chan_write_failed(c);
968 c->type = SSH_CHANNEL_OPEN;
969 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
973 /* try to decode a socks4 header */
976 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
979 u_int len, have, i, found;
985 struct in_addr dest_addr;
988 debug2("channel %d: decode socks4", c->self);
990 have = buffer_len(&c->input);
991 len = sizeof(s4_req);
994 p = buffer_ptr(&c->input);
995 for (found = 0, i = len; i < have; i++) {
1001 /* the peer is probably sending garbage */
1002 debug("channel %d: decode socks4: too long",
1009 buffer_get(&c->input, (char *)&s4_req.version, 1);
1010 buffer_get(&c->input, (char *)&s4_req.command, 1);
1011 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1012 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1013 have = buffer_len(&c->input);
1014 p = buffer_ptr(&c->input);
1016 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1018 fatal("channel %d: decode socks4: len %d > have %d",
1019 c->self, len, have);
1020 strlcpy(username, p, sizeof(username));
1021 buffer_consume(&c->input, len);
1022 buffer_consume(&c->input, 1); /* trailing '\0' */
1024 host = inet_ntoa(s4_req.dest_addr);
1025 strlcpy(c->path, host, sizeof(c->path));
1026 c->host_port = ntohs(s4_req.dest_port);
1028 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1029 c->self, host, c->host_port, s4_req.command);
1031 if (s4_req.command != 1) {
1032 debug("channel %d: cannot handle: socks4 cn %d",
1033 c->self, s4_req.command);
1036 s4_rsp.version = 0; /* vn: 0 for reply */
1037 s4_rsp.command = 90; /* cd: req granted */
1038 s4_rsp.dest_port = 0; /* ignored */
1039 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1040 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1044 /* try to decode a socks5 header */
1045 #define SSH_SOCKS5_AUTHDONE 0x1000
1046 #define SSH_SOCKS5_NOAUTH 0x00
1047 #define SSH_SOCKS5_IPV4 0x01
1048 #define SSH_SOCKS5_DOMAIN 0x03
1049 #define SSH_SOCKS5_IPV6 0x04
1050 #define SSH_SOCKS5_CONNECT 0x01
1051 #define SSH_SOCKS5_SUCCESS 0x00
1055 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1063 u_int16_t dest_port;
1064 u_char *p, dest_addr[255+1];
1065 u_int have, need, i, found, nmethods, addrlen, af;
1067 debug2("channel %d: decode socks5", c->self);
1068 p = buffer_ptr(&c->input);
1071 have = buffer_len(&c->input);
1072 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1073 /* format: ver | nmethods | methods */
1077 if (have < nmethods + 2)
1079 /* look for method: "NO AUTHENTICATION REQUIRED" */
1080 for (found = 0, i = 2; i < nmethods + 2; i++) {
1081 if (p[i] == SSH_SOCKS5_NOAUTH) {
1087 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1091 buffer_consume(&c->input, nmethods + 2);
1092 buffer_put_char(&c->output, 0x05); /* version */
1093 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1094 FD_SET(c->sock, writeset);
1095 c->flags |= SSH_SOCKS5_AUTHDONE;
1096 debug2("channel %d: socks5 auth done", c->self);
1097 return 0; /* need more */
1099 debug2("channel %d: socks5 post auth", c->self);
1100 if (have < sizeof(s5_req)+1)
1101 return 0; /* need more */
1102 memcpy(&s5_req, p, sizeof(s5_req));
1103 if (s5_req.version != 0x05 ||
1104 s5_req.command != SSH_SOCKS5_CONNECT ||
1105 s5_req.reserved != 0x00) {
1106 debug2("channel %d: only socks5 connect supported", c->self);
1109 switch (s5_req.atyp){
1110 case SSH_SOCKS5_IPV4:
1114 case SSH_SOCKS5_DOMAIN:
1115 addrlen = p[sizeof(s5_req)];
1118 case SSH_SOCKS5_IPV6:
1123 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1126 need = sizeof(s5_req) + addrlen + 2;
1127 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1131 buffer_consume(&c->input, sizeof(s5_req));
1132 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1133 buffer_consume(&c->input, 1); /* host string length */
1134 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1135 buffer_get(&c->input, (char *)&dest_port, 2);
1136 dest_addr[addrlen] = '\0';
1137 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1138 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1139 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1141 c->host_port = ntohs(dest_port);
1143 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1144 c->self, c->path, c->host_port, s5_req.command);
1146 s5_rsp.version = 0x05;
1147 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1148 s5_rsp.reserved = 0; /* ignored */
1149 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1150 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1151 dest_port = 0; /* ignored */
1153 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1154 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1155 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1159 /* dynamic port forwarding */
1161 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1167 have = buffer_len(&c->input);
1169 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1170 /* buffer_dump(&c->input); */
1171 /* check if the fixed size part of the packet is in buffer. */
1174 FD_SET(c->sock, readset);
1177 /* try to guess the protocol */
1178 p = buffer_ptr(&c->input);
1181 ret = channel_decode_socks4(c, readset, writeset);
1184 ret = channel_decode_socks5(c, readset, writeset);
1192 } else if (ret == 0) {
1193 debug2("channel %d: pre_dynamic: need more", c->self);
1195 FD_SET(c->sock, readset);
1197 /* switch to the next state */
1198 c->type = SSH_CHANNEL_OPENING;
1199 port_open_helper(c, "direct-tcpip");
1203 /* This is our fake X11 server socket. */
1206 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1209 struct sockaddr addr;
1212 char buf[16384], *remote_ipaddr;
1215 if (FD_ISSET(c->sock, readset)) {
1216 debug("X11 connection requested.");
1217 addrlen = sizeof(addr);
1218 newsock = accept(c->sock, &addr, &addrlen);
1219 if (c->single_connection) {
1220 debug2("single_connection: closing X11 listener.");
1221 channel_close_fd(&c->sock);
1225 error("accept: %.100s", strerror(errno));
1228 set_nodelay(newsock);
1229 remote_ipaddr = get_peer_ipaddr(newsock);
1230 remote_port = get_peer_port(newsock);
1231 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1232 remote_ipaddr, remote_port);
1234 nc = channel_new("accepted x11 socket",
1235 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1236 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1238 packet_start(SSH2_MSG_CHANNEL_OPEN);
1239 packet_put_cstring("x11");
1240 packet_put_int(nc->self);
1241 packet_put_int(nc->local_window_max);
1242 packet_put_int(nc->local_maxpacket);
1243 /* originator ipaddr and port */
1244 packet_put_cstring(remote_ipaddr);
1245 if (datafellows & SSH_BUG_X11FWD) {
1246 debug2("ssh2 x11 bug compat mode");
1248 packet_put_int(remote_port);
1252 packet_start(SSH_SMSG_X11_OPEN);
1253 packet_put_int(nc->self);
1254 if (packet_get_protocol_flags() &
1255 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1256 packet_put_cstring(buf);
1259 xfree(remote_ipaddr);
1264 port_open_helper(Channel *c, char *rtype)
1268 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1269 int remote_port = get_peer_port(c->sock);
1271 direct = (strcmp(rtype, "direct-tcpip") == 0);
1273 snprintf(buf, sizeof buf,
1274 "%s: listening port %d for %.100s port %d, "
1275 "connect from %.200s port %d",
1276 rtype, c->listening_port, c->path, c->host_port,
1277 remote_ipaddr, remote_port);
1279 xfree(c->remote_name);
1280 c->remote_name = xstrdup(buf);
1283 packet_start(SSH2_MSG_CHANNEL_OPEN);
1284 packet_put_cstring(rtype);
1285 packet_put_int(c->self);
1286 packet_put_int(c->local_window_max);
1287 packet_put_int(c->local_maxpacket);
1289 /* target host, port */
1290 packet_put_cstring(c->path);
1291 packet_put_int(c->host_port);
1293 /* listen address, port */
1294 packet_put_cstring(c->path);
1295 packet_put_int(c->listening_port);
1297 /* originator host and port */
1298 packet_put_cstring(remote_ipaddr);
1299 packet_put_int((u_int)remote_port);
1302 packet_start(SSH_MSG_PORT_OPEN);
1303 packet_put_int(c->self);
1304 packet_put_cstring(c->path);
1305 packet_put_int(c->host_port);
1306 if (packet_get_protocol_flags() &
1307 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1308 packet_put_cstring(c->remote_name);
1311 xfree(remote_ipaddr);
1315 channel_set_reuseaddr(int fd)
1320 * Set socket options.
1321 * Allow local port reuse in TIME_WAIT.
1323 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1324 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1328 * This socket is listening for connections to a forwarded TCP/IP port.
1332 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1335 struct sockaddr addr;
1336 int newsock, nextstate;
1340 if (FD_ISSET(c->sock, readset)) {
1341 debug("Connection to port %d forwarding "
1342 "to %.100s port %d requested.",
1343 c->listening_port, c->path, c->host_port);
1345 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1346 nextstate = SSH_CHANNEL_OPENING;
1347 rtype = "forwarded-tcpip";
1349 if (c->host_port == 0) {
1350 nextstate = SSH_CHANNEL_DYNAMIC;
1351 rtype = "dynamic-tcpip";
1353 nextstate = SSH_CHANNEL_OPENING;
1354 rtype = "direct-tcpip";
1358 addrlen = sizeof(addr);
1359 newsock = accept(c->sock, &addr, &addrlen);
1361 error("accept: %.100s", strerror(errno));
1364 set_nodelay(newsock);
1365 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1366 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1367 nc->listening_port = c->listening_port;
1368 nc->host_port = c->host_port;
1369 strlcpy(nc->path, c->path, sizeof(nc->path));
1371 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1373 * do not call the channel_post handler until
1374 * this flag has been reset by a pre-handler.
1375 * otherwise the FD_ISSET calls might overflow
1379 port_open_helper(nc, rtype);
1385 * This is the authentication agent socket listening for connections from
1390 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1394 struct sockaddr addr;
1397 if (FD_ISSET(c->sock, readset)) {
1398 addrlen = sizeof(addr);
1399 newsock = accept(c->sock, &addr, &addrlen);
1401 error("accept from auth socket: %.100s", strerror(errno));
1404 nc = channel_new("accepted auth socket",
1405 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1406 c->local_window_max, c->local_maxpacket,
1407 0, "accepted auth socket", 1);
1409 packet_start(SSH2_MSG_CHANNEL_OPEN);
1410 packet_put_cstring("auth-agent@openssh.com");
1411 packet_put_int(nc->self);
1412 packet_put_int(c->local_window_max);
1413 packet_put_int(c->local_maxpacket);
1415 packet_start(SSH_SMSG_AGENT_OPEN);
1416 packet_put_int(nc->self);
1424 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1427 socklen_t sz = sizeof(err);
1429 if (FD_ISSET(c->sock, writeset)) {
1430 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1432 error("getsockopt SO_ERROR failed");
1435 debug("channel %d: connected", c->self);
1436 c->type = SSH_CHANNEL_OPEN;
1438 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1439 packet_put_int(c->remote_id);
1440 packet_put_int(c->self);
1441 packet_put_int(c->local_window);
1442 packet_put_int(c->local_maxpacket);
1444 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1445 packet_put_int(c->remote_id);
1446 packet_put_int(c->self);
1449 debug("channel %d: not connected: %s",
1450 c->self, strerror(err));
1452 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1453 packet_put_int(c->remote_id);
1454 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1455 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1456 packet_put_cstring(strerror(err));
1457 packet_put_cstring("");
1460 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1461 packet_put_int(c->remote_id);
1471 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1473 char buf[CHAN_RBUF];
1476 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1477 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1479 len = read(c->rfd, buf, sizeof(buf));
1480 if (len < 0 && (errno == EINTR || (errno == EAGAIN && !force)))
1482 #ifndef PTY_ZEROREAD
1485 if ((!c->isatty && len <= 0) ||
1486 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1488 debug2("channel %d: read<=0 rfd %d len %d",
1489 c->self, c->rfd, len);
1490 if (c->type != SSH_CHANNEL_OPEN) {
1491 debug2("channel %d: not open", c->self);
1494 } else if (compat13) {
1495 buffer_clear(&c->output);
1496 c->type = SSH_CHANNEL_INPUT_DRAINING;
1497 debug2("channel %d: input draining.", c->self);
1499 chan_read_failed(c);
1503 if (c->input_filter != NULL) {
1504 if (c->input_filter(c, buf, len) == -1) {
1505 debug2("channel %d: filter stops", c->self);
1506 chan_read_failed(c);
1508 } else if (c->datagram) {
1509 buffer_put_string(&c->input, buf, len);
1511 buffer_append(&c->input, buf, len);
1519 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1522 u_char *data = NULL, *buf;
1526 /* Send buffered output data to the socket. */
1528 FD_ISSET(c->wfd, writeset) &&
1529 buffer_len(&c->output) > 0) {
1530 if (c->output_filter != NULL) {
1531 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1532 debug2("channel %d: filter stops", c->self);
1533 if (c->type != SSH_CHANNEL_OPEN)
1536 chan_write_failed(c);
1539 } else if (c->datagram) {
1540 buf = data = buffer_get_string(&c->output, &dlen);
1542 buf = data = buffer_ptr(&c->output);
1543 dlen = buffer_len(&c->output);
1547 /* ignore truncated writes, datagrams might get lost */
1548 c->local_consumed += dlen + 4;
1549 len = write(c->wfd, buf, dlen);
1551 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1554 if (c->type != SSH_CHANNEL_OPEN)
1557 chan_write_failed(c);
1563 /* XXX: Later AIX versions can't push as much data to tty */
1564 if (compat20 && c->wfd_isatty)
1565 dlen = MIN(dlen, 8*1024);
1568 len = write(c->wfd, buf, dlen);
1569 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1572 if (c->type != SSH_CHANNEL_OPEN) {
1573 debug2("channel %d: not open", c->self);
1576 } else if (compat13) {
1577 buffer_clear(&c->output);
1578 debug2("channel %d: input draining.", c->self);
1579 c->type = SSH_CHANNEL_INPUT_DRAINING;
1581 chan_write_failed(c);
1585 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1586 if (tcgetattr(c->wfd, &tio) == 0 &&
1587 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1589 * Simulate echo to reduce the impact of
1590 * traffic analysis. We need to match the
1591 * size of a SSH2_MSG_CHANNEL_DATA message
1592 * (4 byte channel id + buf)
1594 packet_send_ignore(4 + len);
1598 buffer_consume(&c->output, len);
1599 if (compat20 && len > 0) {
1600 c->local_consumed += len;
1607 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1609 char buf[CHAN_RBUF];
1612 /** XXX handle drain efd, too */
1614 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1615 FD_ISSET(c->efd, writeset) &&
1616 buffer_len(&c->extended) > 0) {
1617 len = write(c->efd, buffer_ptr(&c->extended),
1618 buffer_len(&c->extended));
1619 debug2("channel %d: written %d to efd %d",
1620 c->self, len, c->efd);
1621 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1624 debug2("channel %d: closing write-efd %d",
1626 channel_close_fd(&c->efd);
1628 buffer_consume(&c->extended, len);
1629 c->local_consumed += len;
1631 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1632 (c->detach_close || FD_ISSET(c->efd, readset))) {
1633 len = read(c->efd, buf, sizeof(buf));
1634 debug2("channel %d: read %d from efd %d",
1635 c->self, len, c->efd);
1636 if (len < 0 && (errno == EINTR ||
1637 (errno == EAGAIN && !c->detach_close)))
1640 debug2("channel %d: closing read-efd %d",
1642 channel_close_fd(&c->efd);
1644 buffer_append(&c->extended, buf, len);
1653 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1658 /* Monitor control fd to detect if the slave client exits */
1659 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1660 len = read(c->ctl_fd, buf, sizeof(buf));
1661 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1664 debug2("channel %d: ctl read<=0", c->self);
1665 if (c->type != SSH_CHANNEL_OPEN) {
1666 debug2("channel %d: not open", c->self);
1670 chan_read_failed(c);
1671 chan_write_failed(c);
1675 fatal("%s: unexpected data on ctl fd", __func__);
1681 channel_check_window(Channel *c)
1683 if (c->type == SSH_CHANNEL_OPEN &&
1684 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1685 ((c->local_window_max - c->local_window >
1686 c->local_maxpacket*3) ||
1687 c->local_window < c->local_window_max/2) &&
1688 c->local_consumed > 0) {
1690 /* adjust max window size if we are in a dynamic environment */
1691 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1692 /* grow the window somewhat aggressively to maintain pressure */
1693 addition = 1.5*(c->tcpwinsz - c->local_window_max);
1694 c->local_window_max += addition;
1696 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1697 packet_put_int(c->remote_id);
1698 packet_put_int(c->local_consumed + addition);
1700 debug2("channel %d: window %d sent adjust %d",
1701 c->self, c->local_window,
1703 c->local_window += c->local_consumed + addition;
1704 c->local_consumed = 0;
1710 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1714 channel_handle_rfd(c, readset, writeset);
1715 channel_handle_wfd(c, readset, writeset);
1718 channel_handle_efd(c, readset, writeset);
1719 channel_handle_ctl(c, readset, writeset);
1720 channel_check_window(c);
1725 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1729 /* Send buffered output data to the socket. */
1730 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1731 len = write(c->sock, buffer_ptr(&c->output),
1732 buffer_len(&c->output));
1734 buffer_clear(&c->output);
1736 buffer_consume(&c->output, len);
1741 channel_handler_init_20(void)
1743 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1744 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1745 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1746 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1747 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1748 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1749 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1750 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1752 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1753 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1754 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1755 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1756 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1757 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1758 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1762 channel_handler_init_13(void)
1764 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1765 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1766 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1767 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1768 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1769 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1770 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1771 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1772 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1774 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1775 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1776 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1777 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1778 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1779 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1780 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1784 channel_handler_init_15(void)
1786 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1787 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1788 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1789 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1790 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1791 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1792 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1794 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1795 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1796 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1797 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1798 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1799 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1803 channel_handler_init(void)
1807 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1808 channel_pre[i] = NULL;
1809 channel_post[i] = NULL;
1812 channel_handler_init_20();
1814 channel_handler_init_13();
1816 channel_handler_init_15();
1819 /* gc dead channels */
1821 channel_garbage_collect(Channel *c)
1825 if (c->detach_user != NULL) {
1826 if (!chan_is_dead(c, c->detach_close))
1828 debug2("channel %d: gc: notify user", c->self);
1829 c->detach_user(c->self, NULL);
1830 /* if we still have a callback */
1831 if (c->detach_user != NULL)
1833 debug2("channel %d: gc: user detached", c->self);
1835 if (!chan_is_dead(c, 1))
1837 debug2("channel %d: garbage collecting", c->self);
1842 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1844 static int did_init = 0;
1849 channel_handler_init();
1852 for (i = 0; i < channels_alloc; i++) {
1856 if (ftab[c->type] != NULL)
1857 (*ftab[c->type])(c, readset, writeset);
1858 channel_garbage_collect(c);
1863 * Allocate/update select bitmasks and add any bits relevant to channels in
1867 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1868 u_int *nallocp, int rekeying)
1870 u_int n, sz, nfdset;
1872 n = MAX(*maxfdp, channel_max_fd);
1874 nfdset = howmany(n+1, NFDBITS);
1875 /* Explicitly test here, because xrealloc isn't always called */
1876 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1877 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1878 sz = nfdset * sizeof(fd_mask);
1880 /* perhaps check sz < nalloc/2 and shrink? */
1881 if (*readsetp == NULL || sz > *nallocp) {
1882 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1883 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1887 memset(*readsetp, 0, sz);
1888 memset(*writesetp, 0, sz);
1891 channel_handler(channel_pre, *readsetp, *writesetp);
1895 * After select, perform any appropriate operations for channels which have
1899 channel_after_select(fd_set *readset, fd_set *writeset)
1901 channel_handler(channel_post, readset, writeset);
1905 /* If there is data to send to the connection, enqueue some of it now. */
1907 channel_output_poll(void)
1911 int packet_length = 0;
1913 for (i = 0; i < channels_alloc; i++) {
1919 * We are only interested in channels that can have buffered
1923 if (c->type != SSH_CHANNEL_OPEN &&
1924 c->type != SSH_CHANNEL_INPUT_DRAINING)
1927 if (c->type != SSH_CHANNEL_OPEN)
1931 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1932 /* XXX is this true? */
1933 debug3("channel %d: will not send data after close", c->self);
1937 /* Get the amount of buffered data for this channel. */
1938 if ((c->istate == CHAN_INPUT_OPEN ||
1939 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1940 (len = buffer_len(&c->input)) > 0) {
1946 data = buffer_get_string(&c->input,
1948 packet_start(SSH2_MSG_CHANNEL_DATA);
1949 packet_put_int(c->remote_id);
1950 packet_put_string(data, dlen);
1951 packet_length = packet_send();
1952 c->remote_window -= dlen + 4;
1958 * Send some data for the other side over the secure
1962 if (len > c->remote_window)
1963 len = c->remote_window;
1964 if (len > c->remote_maxpacket)
1965 len = c->remote_maxpacket;
1967 if (packet_is_interactive()) {
1971 /* Keep the packets at reasonable size. */
1972 if (len > packet_get_maxsize()/2)
1973 len = packet_get_maxsize()/2;
1977 packet_start(compat20 ?
1978 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1979 packet_put_int(c->remote_id);
1980 packet_put_string(buffer_ptr(&c->input), len);
1981 packet_length = packet_send();
1982 buffer_consume(&c->input, len);
1983 c->remote_window -= len;
1985 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1987 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1989 * input-buffer is empty and read-socket shutdown:
1990 * tell peer, that we will not send more data: send IEOF.
1991 * hack for extended data: delay EOF if EFD still in use.
1993 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1994 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1995 c->self, c->efd, buffer_len(&c->extended));
1999 /* Send extended data, i.e. stderr */
2001 !(c->flags & CHAN_EOF_SENT) &&
2002 c->remote_window > 0 &&
2003 (len = buffer_len(&c->extended)) > 0 &&
2004 c->extended_usage == CHAN_EXTENDED_READ) {
2005 debug2("channel %d: rwin %u elen %u euse %d",
2006 c->self, c->remote_window, buffer_len(&c->extended),
2008 if (len > c->remote_window)
2009 len = c->remote_window;
2010 if (len > c->remote_maxpacket)
2011 len = c->remote_maxpacket;
2012 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2013 packet_put_int(c->remote_id);
2014 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2015 packet_put_string(buffer_ptr(&c->extended), len);
2016 packet_length = packet_send();
2017 buffer_consume(&c->extended, len);
2018 c->remote_window -= len;
2019 debug2("channel %d: sent ext data %d", c->self, len);
2022 return (packet_length);
2026 /* -- protocol input */
2030 channel_input_data(int type, u_int32_t seq, void *ctxt)
2037 /* Get the channel number and verify it. */
2038 id = packet_get_int();
2039 c = channel_lookup(id);
2041 packet_disconnect("Received data for nonexistent channel %d.", id);
2043 /* Ignore any data for non-open channels (might happen on close) */
2044 if (c->type != SSH_CHANNEL_OPEN &&
2045 c->type != SSH_CHANNEL_X11_OPEN)
2049 data = packet_get_string(&data_len);
2052 * Ignore data for protocol > 1.3 if output end is no longer open.
2053 * For protocol 2 the sending side is reducing its window as it sends
2054 * data, so we must 'fake' consumption of the data in order to ensure
2055 * that window updates are sent back. Otherwise the connection might
2058 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2060 c->local_window -= data_len;
2061 c->local_consumed += data_len;
2068 if (data_len > c->local_maxpacket) {
2069 logit("channel %d: rcvd big packet %d, maxpack %d",
2070 c->self, data_len, c->local_maxpacket);
2072 if (data_len > c->local_window) {
2073 logit("channel %d: rcvd too much data %d, win %d",
2074 c->self, data_len, c->local_window);
2078 c->local_window -= data_len;
2082 buffer_put_string(&c->output, data, data_len);
2084 buffer_append(&c->output, data, data_len);
2090 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2094 u_int data_len, tcode;
2097 /* Get the channel number and verify it. */
2098 id = packet_get_int();
2099 c = channel_lookup(id);
2102 packet_disconnect("Received extended_data for bad channel %d.", id);
2103 if (c->type != SSH_CHANNEL_OPEN) {
2104 logit("channel %d: ext data for non open", id);
2107 if (c->flags & CHAN_EOF_RCVD) {
2108 if (datafellows & SSH_BUG_EXTEOF)
2109 debug("channel %d: accepting ext data after eof", id);
2111 packet_disconnect("Received extended_data after EOF "
2112 "on channel %d.", id);
2114 tcode = packet_get_int();
2116 c->extended_usage != CHAN_EXTENDED_WRITE ||
2117 tcode != SSH2_EXTENDED_DATA_STDERR) {
2118 logit("channel %d: bad ext data", c->self);
2121 data = packet_get_string(&data_len);
2123 if (data_len > c->local_window) {
2124 logit("channel %d: rcvd too much extended_data %d, win %d",
2125 c->self, data_len, c->local_window);
2129 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2130 c->local_window -= data_len;
2131 buffer_append(&c->extended, data, data_len);
2137 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2142 id = packet_get_int();
2144 c = channel_lookup(id);
2146 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2149 /* XXX force input close */
2150 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2151 debug("channel %d: FORCE input drain", c->self);
2152 c->istate = CHAN_INPUT_WAIT_DRAIN;
2153 if (buffer_len(&c->input) == 0)
2161 channel_input_close(int type, u_int32_t seq, void *ctxt)
2166 id = packet_get_int();
2168 c = channel_lookup(id);
2170 packet_disconnect("Received close for nonexistent channel %d.", id);
2173 * Send a confirmation that we have closed the channel and no more
2174 * data is coming for it.
2176 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2177 packet_put_int(c->remote_id);
2181 * If the channel is in closed state, we have sent a close request,
2182 * and the other side will eventually respond with a confirmation.
2183 * Thus, we cannot free the channel here, because then there would be
2184 * no-one to receive the confirmation. The channel gets freed when
2185 * the confirmation arrives.
2187 if (c->type != SSH_CHANNEL_CLOSED) {
2189 * Not a closed channel - mark it as draining, which will
2190 * cause it to be freed later.
2192 buffer_clear(&c->input);
2193 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2197 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2200 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2202 int id = packet_get_int();
2203 Channel *c = channel_lookup(id);
2207 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2208 chan_rcvd_oclose(c);
2213 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2215 int id = packet_get_int();
2216 Channel *c = channel_lookup(id);
2220 packet_disconnect("Received close confirmation for "
2221 "out-of-range channel %d.", id);
2222 if (c->type != SSH_CHANNEL_CLOSED)
2223 packet_disconnect("Received close confirmation for "
2224 "non-closed channel %d (type %d).", id, c->type);
2230 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2235 id = packet_get_int();
2236 c = channel_lookup(id);
2238 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2239 packet_disconnect("Received open confirmation for "
2240 "non-opening channel %d.", id);
2241 remote_id = packet_get_int();
2242 /* Record the remote channel number and mark that the channel is now open. */
2243 c->remote_id = remote_id;
2244 c->type = SSH_CHANNEL_OPEN;
2247 c->remote_window = packet_get_int();
2248 c->remote_maxpacket = packet_get_int();
2250 debug2("callback start");
2251 c->confirm(c->self, c->confirm_ctx);
2252 debug2("callback done");
2254 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2255 c->remote_window, c->remote_maxpacket);
2261 reason2txt(int reason)
2264 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2265 return "administratively prohibited";
2266 case SSH2_OPEN_CONNECT_FAILED:
2267 return "connect failed";
2268 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2269 return "unknown channel type";
2270 case SSH2_OPEN_RESOURCE_SHORTAGE:
2271 return "resource shortage";
2273 return "unknown reason";
2278 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2281 char *msg = NULL, *lang = NULL;
2284 id = packet_get_int();
2285 c = channel_lookup(id);
2287 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2288 packet_disconnect("Received open failure for "
2289 "non-opening channel %d.", id);
2291 reason = packet_get_int();
2292 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2293 msg = packet_get_string(NULL);
2294 lang = packet_get_string(NULL);
2296 logit("channel %d: open failed: %s%s%s", id,
2297 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2304 /* Free the channel. This will also close the socket. */
2310 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2319 /* Get the channel number and verify it. */
2320 id = packet_get_int();
2321 c = channel_lookup(id);
2324 logit("Received window adjust for non-open channel %d.", id);
2327 adjust = packet_get_int();
2329 debug2("channel %d: rcvd adjust %u", id, adjust);
2330 c->remote_window += adjust;
2335 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2339 char *host, *originator_string;
2340 int remote_id, sock = -1;
2342 remote_id = packet_get_int();
2343 host = packet_get_string(NULL);
2344 host_port = packet_get_int();
2346 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2347 originator_string = packet_get_string(NULL);
2349 originator_string = xstrdup("unknown (remote did not supply name)");
2352 sock = channel_connect_to(host, host_port);
2354 c = channel_new("connected socket",
2355 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2356 originator_string, 1);
2357 c->remote_id = remote_id;
2359 xfree(originator_string);
2361 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2362 packet_put_int(remote_id);
2369 /* -- tcp forwarding */
2372 channel_set_af(int af)
2378 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2379 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2380 int hpn_disabled, int hpn_buffer_size)
2383 int sock, r, success = 0, wildcard = 0, is_client;
2384 struct addrinfo hints, *ai, *aitop;
2385 const char *host, *addr;
2386 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2388 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2389 listen_addr : host_to_connect;
2390 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2393 error("No forward host name.");
2396 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2397 error("Forward host name too long.");
2402 * Determine whether or not a port forward listens to loopback,
2403 * specified address or wildcard. On the client, a specified bind
2404 * address will always override gateway_ports. On the server, a
2405 * gateway_ports of 1 (``yes'') will override the client's
2406 * specification and force a wildcard bind, whereas a value of 2
2407 * (``clientspecified'') will bind to whatever address the client
2410 * Special-case listen_addrs are:
2412 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2413 * "" (empty string), "*" -> wildcard v4/v6
2414 * "localhost" -> loopback v4/v6
2417 if (listen_addr == NULL) {
2418 /* No address specified: default to gateway_ports setting */
2421 } else if (gateway_ports || is_client) {
2422 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2423 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2424 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2425 (!is_client && gateway_ports == 1))
2427 else if (strcmp(listen_addr, "localhost") != 0)
2431 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2432 type, wildcard, (addr == NULL) ? "NULL" : addr);
2435 * getaddrinfo returns a loopback address if the hostname is
2436 * set to NULL and hints.ai_flags is not AI_PASSIVE
2438 memset(&hints, 0, sizeof(hints));
2439 hints.ai_family = IPv4or6;
2440 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2441 hints.ai_socktype = SOCK_STREAM;
2442 snprintf(strport, sizeof strport, "%d", listen_port);
2443 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2445 /* This really shouldn't happen */
2446 packet_disconnect("getaddrinfo: fatal error: %s",
2447 ssh_gai_strerror(r));
2449 error("channel_setup_fwd_listener: "
2450 "getaddrinfo(%.64s): %s", addr,
2451 ssh_gai_strerror(r));
2456 for (ai = aitop; ai; ai = ai->ai_next) {
2457 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2459 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2460 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2461 error("channel_setup_fwd_listener: getnameinfo failed");
2464 /* Create a port to listen for the host. */
2465 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2467 /* this is no error since kernel may not support ipv6 */
2468 verbose("socket: %.100s", strerror(errno));
2472 channel_set_reuseaddr(sock);
2474 debug("Local forwarding listening on %s port %s.", ntop, strport);
2476 /* Bind the socket to the address. */
2477 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2478 /* address can be in use ipv6 address is already bound */
2480 error("bind: %.100s", strerror(errno));
2482 verbose("bind: %.100s", strerror(errno));
2487 /* Start listening for connections on the socket. */
2488 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2489 error("listen: %.100s", strerror(errno));
2493 /* Allocate a channel number for the socket. */
2494 /* explicitly test for hpn disabled option. if true use smaller window size */
2496 c = channel_new("port listener", type, sock, sock, -1,
2497 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2498 0, "port listener", 1);
2500 c = channel_new("port listener", type, sock, sock, -1,
2501 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2502 0, "port listener", 1);
2503 strlcpy(c->path, host, sizeof(c->path));
2504 c->host_port = port_to_connect;
2505 c->listening_port = listen_port;
2509 error("channel_setup_fwd_listener: cannot listen to port: %d",
2511 freeaddrinfo(aitop);
2516 channel_cancel_rport_listener(const char *host, u_short port)
2521 for (i = 0; i < channels_alloc; i++) {
2522 Channel *c = channels[i];
2524 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2525 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2526 c->listening_port == port) {
2527 debug2("%s: close channel %d", __func__, i);
2536 /* protocol local port fwd, used by ssh (and sshd in v1) */
2538 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2539 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2540 int hpn_disabled, int hpn_buffer_size)
2542 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2543 listen_host, listen_port, host_to_connect, port_to_connect,
2544 gateway_ports, hpn_disabled, hpn_buffer_size);
2547 /* protocol v2 remote port fwd, used by sshd */
2549 channel_setup_remote_fwd_listener(const char *listen_address,
2550 u_short listen_port, int gateway_ports, int hpn_disabled, int hpn_buffer_size)
2552 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2553 listen_address, listen_port, NULL, 0, gateway_ports,
2554 hpn_disabled, hpn_buffer_size);
2558 * Initiate forwarding of connections to port "port" on remote host through
2559 * the secure channel to host:port from local side.
2563 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2564 const char *host_to_connect, u_short port_to_connect)
2566 int type, success = 0;
2568 /* Record locally that connection to this host/port is permitted. */
2569 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2570 fatal("channel_request_remote_forwarding: too many forwards");
2572 /* Send the forward request to the remote side. */
2574 const char *address_to_bind;
2575 if (listen_host == NULL) {
2576 if (datafellows & SSH_BUG_RFWD_ADDR)
2577 address_to_bind = "127.0.0.1";
2579 address_to_bind = "localhost";
2580 } else if (*listen_host == '\0' ||
2581 strcmp(listen_host, "*") == 0) {
2582 if (datafellows & SSH_BUG_RFWD_ADDR)
2583 address_to_bind = "0.0.0.0";
2585 address_to_bind = "";
2587 address_to_bind = listen_host;
2589 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2590 packet_put_cstring("tcpip-forward");
2591 packet_put_char(1); /* boolean: want reply */
2592 packet_put_cstring(address_to_bind);
2593 packet_put_int(listen_port);
2595 packet_write_wait();
2596 /* Assume that server accepts the request */
2599 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2600 packet_put_int(listen_port);
2601 packet_put_cstring(host_to_connect);
2602 packet_put_int(port_to_connect);
2604 packet_write_wait();
2606 /* Wait for response from the remote side. */
2607 type = packet_read();
2609 case SSH_SMSG_SUCCESS:
2612 case SSH_SMSG_FAILURE:
2615 /* Unknown packet */
2616 packet_disconnect("Protocol error for port forward request:"
2617 "received packet type %d.", type);
2621 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2622 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2623 permitted_opens[num_permitted_opens].listen_port = listen_port;
2624 num_permitted_opens++;
2626 return (success ? 0 : -1);
2630 * Request cancellation of remote forwarding of connection host:port from
2634 channel_request_rforward_cancel(const char *host, u_short port)
2641 for (i = 0; i < num_permitted_opens; i++) {
2642 if (permitted_opens[i].host_to_connect != NULL &&
2643 permitted_opens[i].listen_port == port)
2646 if (i >= num_permitted_opens) {
2647 debug("%s: requested forward not found", __func__);
2650 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2651 packet_put_cstring("cancel-tcpip-forward");
2653 packet_put_cstring(host == NULL ? "" : host);
2654 packet_put_int(port);
2657 permitted_opens[i].listen_port = 0;
2658 permitted_opens[i].port_to_connect = 0;
2659 xfree(permitted_opens[i].host_to_connect);
2660 permitted_opens[i].host_to_connect = NULL;
2664 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2665 * listening for the port, and sends back a success reply (or disconnect
2666 * message if there was an error).
2669 channel_input_port_forward_request(int is_root, int gateway_ports,
2670 int hpn_disabled, int hpn_buffer_size)
2672 u_short port, host_port;
2676 /* Get arguments from the packet. */
2677 port = packet_get_int();
2678 hostname = packet_get_string(NULL);
2679 host_port = packet_get_int();
2683 * Check that an unprivileged user is not trying to forward a
2686 if (port < IPPORT_RESERVED && !is_root)
2688 "Requested forwarding of port %d but user is not root.",
2691 packet_disconnect("Dynamic forwarding denied.");
2694 /* Initiate forwarding */
2695 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2696 host_port, gateway_ports, hpn_disabled, hpn_buffer_size);
2698 /* Free the argument string. */
2701 return (success ? 0 : -1);
2705 * Permits opening to any host/port if permitted_opens[] is empty. This is
2706 * usually called by the server, because the user could connect to any port
2707 * anyway, and the server has no way to know but to trust the client anyway.
2710 channel_permit_all_opens(void)
2712 if (num_permitted_opens == 0)
2713 all_opens_permitted = 1;
2717 channel_add_permitted_opens(char *host, int port)
2719 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2720 fatal("channel_add_permitted_opens: too many forwards");
2721 debug("allow port forwarding to host %s port %d", host, port);
2723 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2724 permitted_opens[num_permitted_opens].port_to_connect = port;
2725 num_permitted_opens++;
2727 all_opens_permitted = 0;
2731 channel_add_adm_permitted_opens(char *host, int port)
2733 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2734 fatal("channel_add_adm_permitted_opens: too many forwards");
2735 debug("config allows port forwarding to host %s port %d", host, port);
2737 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2739 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2740 return ++num_adm_permitted_opens;
2744 channel_clear_permitted_opens(void)
2748 for (i = 0; i < num_permitted_opens; i++)
2749 if (permitted_opens[i].host_to_connect != NULL)
2750 xfree(permitted_opens[i].host_to_connect);
2751 num_permitted_opens = 0;
2755 channel_clear_adm_permitted_opens(void)
2759 for (i = 0; i < num_adm_permitted_opens; i++)
2760 if (permitted_adm_opens[i].host_to_connect != NULL)
2761 xfree(permitted_adm_opens[i].host_to_connect);
2762 num_adm_permitted_opens = 0;
2765 /* return socket to remote host, port */
2767 connect_to(const char *host, u_short port)
2769 struct addrinfo hints, *ai, *aitop;
2770 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2774 memset(&hints, 0, sizeof(hints));
2775 hints.ai_family = IPv4or6;
2776 hints.ai_socktype = SOCK_STREAM;
2777 snprintf(strport, sizeof strport, "%d", port);
2778 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2779 error("connect_to %.100s: unknown host (%s)", host,
2780 ssh_gai_strerror(gaierr));
2783 for (ai = aitop; ai; ai = ai->ai_next) {
2784 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2786 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2787 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2788 error("connect_to: getnameinfo failed");
2791 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2793 if (ai->ai_next == NULL)
2794 error("socket: %.100s", strerror(errno));
2796 verbose("socket: %.100s", strerror(errno));
2799 if (set_nonblock(sock) == -1)
2800 fatal("%s: set_nonblock(%d)", __func__, sock);
2801 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2802 errno != EINPROGRESS) {
2803 error("connect_to %.100s port %s: %.100s", ntop, strport,
2806 continue; /* fail -- try next */
2808 break; /* success */
2811 freeaddrinfo(aitop);
2813 error("connect_to %.100s port %d: failed.", host, port);
2822 channel_connect_by_listen_address(u_short listen_port)
2826 for (i = 0; i < num_permitted_opens; i++)
2827 if (permitted_opens[i].host_to_connect != NULL &&
2828 permitted_opens[i].listen_port == listen_port)
2830 permitted_opens[i].host_to_connect,
2831 permitted_opens[i].port_to_connect);
2832 error("WARNING: Server requests forwarding for unknown listen_port %d",
2837 /* Check if connecting to that port is permitted and connect. */
2839 channel_connect_to(const char *host, u_short port)
2841 int i, permit, permit_adm = 1;
2843 permit = all_opens_permitted;
2845 for (i = 0; i < num_permitted_opens; i++)
2846 if (permitted_opens[i].host_to_connect != NULL &&
2847 permitted_opens[i].port_to_connect == port &&
2848 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2852 if (num_adm_permitted_opens > 0) {
2854 for (i = 0; i < num_adm_permitted_opens; i++)
2855 if (permitted_adm_opens[i].host_to_connect != NULL &&
2856 permitted_adm_opens[i].port_to_connect == port &&
2857 strcmp(permitted_adm_opens[i].host_to_connect, host)
2862 if (!permit || !permit_adm) {
2863 logit("Received request to connect to host %.100s port %d, "
2864 "but the request was denied.", host, port);
2867 return connect_to(host, port);
2871 channel_send_window_changes(void)
2876 for (i = 0; i < channels_alloc; i++) {
2877 if (channels[i] == NULL || !channels[i]->client_tty ||
2878 channels[i]->type != SSH_CHANNEL_OPEN)
2880 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2882 channel_request_start(i, "window-change", 0);
2883 packet_put_int((u_int)ws.ws_col);
2884 packet_put_int((u_int)ws.ws_row);
2885 packet_put_int((u_int)ws.ws_xpixel);
2886 packet_put_int((u_int)ws.ws_ypixel);
2891 /* -- X11 forwarding */
2894 * Creates an internet domain socket for listening for X11 connections.
2895 * Returns 0 and a suitable display number for the DISPLAY variable
2896 * stored in display_numberp , or -1 if an error occurs.
2899 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2900 int single_connection, u_int *display_numberp, int **chanids,
2901 int hpn_disabled, int hpn_buffer_size)
2904 int display_number, sock;
2906 struct addrinfo hints, *ai, *aitop;
2907 char strport[NI_MAXSERV];
2908 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2910 if (chanids == NULL)
2913 for (display_number = x11_display_offset;
2914 display_number < MAX_DISPLAYS;
2916 port = 6000 + display_number;
2917 memset(&hints, 0, sizeof(hints));
2918 hints.ai_family = IPv4or6;
2919 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2920 hints.ai_socktype = SOCK_STREAM;
2921 snprintf(strport, sizeof strport, "%d", port);
2922 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2923 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
2926 for (ai = aitop; ai; ai = ai->ai_next) {
2927 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2929 sock = socket(ai->ai_family, ai->ai_socktype,
2932 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2933 error("socket: %.100s", strerror(errno));
2934 freeaddrinfo(aitop);
2937 debug("x11_create_display_inet: Socket family %d not supported",
2943 if (ai->ai_family == AF_INET6) {
2945 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2946 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2949 channel_set_reuseaddr(sock);
2950 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2951 debug2("bind port %d: %.100s", port, strerror(errno));
2954 for (n = 0; n < num_socks; n++) {
2960 socks[num_socks++] = sock;
2961 #ifndef DONT_TRY_OTHER_AF
2962 if (num_socks == NUM_SOCKS)
2965 if (x11_use_localhost) {
2966 if (num_socks == NUM_SOCKS)
2973 freeaddrinfo(aitop);
2977 if (display_number >= MAX_DISPLAYS) {
2978 error("Failed to allocate internet-domain X11 display socket.");
2981 /* Start listening for connections on the socket. */
2982 for (n = 0; n < num_socks; n++) {
2984 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2985 error("listen: %.100s", strerror(errno));
2991 /* Allocate a channel for each socket. */
2992 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2993 for (n = 0; n < num_socks; n++) {
2995 /* Is this really necassary? */
2997 nc = channel_new("x11 listener",
2998 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2999 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3000 0, "X11 inet listener", 1);
3002 nc = channel_new("x11 listener",
3003 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3004 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
3005 0, "X11 inet listener", 1);
3006 nc->single_connection = single_connection;
3007 (*chanids)[n] = nc->self;
3011 /* Return the display number for the DISPLAY environment variable. */
3012 *display_numberp = display_number;
3017 connect_local_xsocket(u_int dnr)
3020 struct sockaddr_un addr;
3022 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3024 error("socket: %.100s", strerror(errno));
3025 memset(&addr, 0, sizeof(addr));
3026 addr.sun_family = AF_UNIX;
3027 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
3028 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3031 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3036 x11_connect_display(void)
3038 u_int display_number;
3039 const char *display;
3040 char buf[1024], *cp;
3041 struct addrinfo hints, *ai, *aitop;
3042 char strport[NI_MAXSERV];
3043 int gaierr, sock = 0;
3045 /* Try to open a socket for the local X server. */
3046 display = getenv("DISPLAY");
3048 error("DISPLAY not set.");
3052 * Now we decode the value of the DISPLAY variable and make a
3053 * connection to the real X server.
3057 * Check if it is a unix domain socket. Unix domain displays are in
3058 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3060 if (strncmp(display, "unix:", 5) == 0 ||
3061 display[0] == ':') {
3062 /* Connect to the unix domain socket. */
3063 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3064 error("Could not parse display number from DISPLAY: %.100s",
3068 /* Create a socket. */
3069 sock = connect_local_xsocket(display_number);
3073 /* OK, we now have a connection to the display. */
3077 * Connect to an inet socket. The DISPLAY value is supposedly
3078 * hostname:d[.s], where hostname may also be numeric IP address.
3080 strlcpy(buf, display, sizeof(buf));
3081 cp = strchr(buf, ':');
3083 error("Could not find ':' in DISPLAY: %.100s", display);
3087 /* buf now contains the host name. But first we parse the display number. */
3088 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3089 error("Could not parse display number from DISPLAY: %.100s",
3094 /* Look up the host address */
3095 memset(&hints, 0, sizeof(hints));
3096 hints.ai_family = IPv4or6;
3097 hints.ai_socktype = SOCK_STREAM;
3098 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3099 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3100 error("%.100s: unknown host. (%s)", buf,
3101 ssh_gai_strerror(gaierr));
3104 for (ai = aitop; ai; ai = ai->ai_next) {
3105 /* Create a socket. */
3106 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3108 debug2("socket: %.100s", strerror(errno));
3111 /* Connect it to the display. */
3112 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3113 debug2("connect %.100s port %u: %.100s", buf,
3114 6000 + display_number, strerror(errno));
3121 freeaddrinfo(aitop);
3123 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3132 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3133 * the remote channel number. We should do whatever we want, and respond
3134 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3139 x11_input_open(int type, u_int32_t seq, void *ctxt)
3142 int remote_id, sock = 0;
3145 debug("Received X11 open request.");
3147 remote_id = packet_get_int();
3149 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3150 remote_host = packet_get_string(NULL);
3152 remote_host = xstrdup("unknown (remote did not supply name)");
3156 /* Obtain a connection to the real X display. */
3157 sock = x11_connect_display();
3159 /* Allocate a channel for this connection. */
3160 c = channel_new("connected x11 socket",
3161 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3163 c->remote_id = remote_id;
3168 /* Send refusal to the remote host. */
3169 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3170 packet_put_int(remote_id);
3172 /* Send a confirmation to the remote host. */
3173 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3174 packet_put_int(remote_id);
3175 packet_put_int(c->self);
3180 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3183 deny_input_open(int type, u_int32_t seq, void *ctxt)
3185 int rchan = packet_get_int();
3188 case SSH_SMSG_AGENT_OPEN:
3189 error("Warning: ssh server tried agent forwarding.");
3191 case SSH_SMSG_X11_OPEN:
3192 error("Warning: ssh server tried X11 forwarding.");
3195 error("deny_input_open: type %d", type);
3198 error("Warning: this is probably a break-in attempt by a malicious server.");
3199 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3200 packet_put_int(rchan);
3205 * Requests forwarding of X11 connections, generates fake authentication
3206 * data, and enables authentication spoofing.
3207 * This should be called in the client only.
3210 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3211 const char *proto, const char *data)
3213 u_int data_len = (u_int) strlen(data) / 2;
3220 if (x11_saved_display == NULL)
3221 x11_saved_display = xstrdup(disp);
3222 else if (strcmp(disp, x11_saved_display) != 0) {
3223 error("x11_request_forwarding_with_spoofing: different "
3224 "$DISPLAY already forwarded");
3228 cp = strchr(disp, ':');
3230 cp = strchr(cp, '.');
3232 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3236 if (x11_saved_proto == NULL) {
3237 /* Save protocol name. */
3238 x11_saved_proto = xstrdup(proto);
3240 * Extract real authentication data and generate fake data
3241 * of the same length.
3243 x11_saved_data = xmalloc(data_len);
3244 x11_fake_data = xmalloc(data_len);
3245 for (i = 0; i < data_len; i++) {
3246 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3247 fatal("x11_request_forwarding: bad "
3248 "authentication data: %.100s", data);
3251 x11_saved_data[i] = value;
3252 x11_fake_data[i] = rnd & 0xff;
3255 x11_saved_data_len = data_len;
3256 x11_fake_data_len = data_len;
3259 /* Convert the fake data into hex. */
3260 new_data = tohex(x11_fake_data, data_len);
3262 /* Send the request packet. */
3264 channel_request_start(client_session_id, "x11-req", 0);
3265 packet_put_char(0); /* XXX bool single connection */
3267 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3269 packet_put_cstring(proto);
3270 packet_put_cstring(new_data);
3271 packet_put_int(screen_number);
3273 packet_write_wait();
3278 /* -- agent forwarding */
3280 /* Sends a message to the server to request authentication fd forwarding. */
3283 auth_request_forwarding(void)
3285 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3287 packet_write_wait();