1 /* $OpenBSD: channels.c,v 1.270 2007/06/25 08:20:03 dtucker 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);
773 if(!packet_connection_is_on_socket())
775 ret = getsockopt(packet_get_connection_in(),
776 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
777 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN)
778 tcpwinsz = BUFFER_MAX_LEN_HPN;
779 debug2("tcpwinsz: %d for connection: %d", tcpwinsz,
780 packet_get_connection_in());
785 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
787 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
789 /* check buffer limits */
791 c->tcpwinsz = channel_tcpwinsz();
792 if (c->dynamic_window > 0)
793 c->tcpwinsz = channel_tcpwinsz();
795 limit = MIN(limit, 2 * c->tcpwinsz);
797 if (c->istate == CHAN_INPUT_OPEN &&
799 buffer_len(&c->input) < limit &&
800 buffer_check_alloc(&c->input, CHAN_RBUF))
801 FD_SET(c->rfd, readset);
802 if (c->ostate == CHAN_OUTPUT_OPEN ||
803 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
804 if (buffer_len(&c->output) > 0) {
805 FD_SET(c->wfd, writeset);
806 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
807 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
808 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
809 c->self, c->efd, buffer_len(&c->extended));
814 /** XXX check close conditions, too */
815 if (compat20 && c->efd != -1) {
816 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
817 buffer_len(&c->extended) > 0)
818 FD_SET(c->efd, writeset);
819 else if (!(c->flags & CHAN_EOF_SENT) &&
820 c->extended_usage == CHAN_EXTENDED_READ &&
821 buffer_len(&c->extended) < c->remote_window)
822 FD_SET(c->efd, readset);
824 /* XXX: What about efd? races? */
825 if (compat20 && c->ctl_fd != -1 &&
826 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
827 FD_SET(c->ctl_fd, readset);
832 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
834 if (buffer_len(&c->input) == 0) {
835 packet_start(SSH_MSG_CHANNEL_CLOSE);
836 packet_put_int(c->remote_id);
838 c->type = SSH_CHANNEL_CLOSED;
839 debug2("channel %d: closing after input drain.", c->self);
845 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
847 if (buffer_len(&c->output) == 0)
850 FD_SET(c->sock, writeset);
854 * This is a special state for X11 authentication spoofing. An opened X11
855 * connection (when authentication spoofing is being done) remains in this
856 * state until the first packet has been completely read. The authentication
857 * data in that packet is then substituted by the real data if it matches the
858 * fake data, and the channel is put into normal mode.
859 * XXX All this happens at the client side.
860 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
863 x11_open_helper(Buffer *b)
866 u_int proto_len, data_len;
868 /* Check if the fixed size part of the packet is in buffer. */
869 if (buffer_len(b) < 12)
872 /* Parse the lengths of variable-length fields. */
874 if (ucp[0] == 0x42) { /* Byte order MSB first. */
875 proto_len = 256 * ucp[6] + ucp[7];
876 data_len = 256 * ucp[8] + ucp[9];
877 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
878 proto_len = ucp[6] + 256 * ucp[7];
879 data_len = ucp[8] + 256 * ucp[9];
881 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
886 /* Check if the whole packet is in buffer. */
888 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
891 /* Check if authentication protocol matches. */
892 if (proto_len != strlen(x11_saved_proto) ||
893 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
894 debug2("X11 connection uses different authentication protocol.");
897 /* Check if authentication data matches our fake data. */
898 if (data_len != x11_fake_data_len ||
899 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
900 x11_fake_data, x11_fake_data_len) != 0) {
901 debug2("X11 auth data does not match fake data.");
904 /* Check fake data length */
905 if (x11_fake_data_len != x11_saved_data_len) {
906 error("X11 fake_data_len %d != saved_data_len %d",
907 x11_fake_data_len, x11_saved_data_len);
911 * Received authentication protocol and data match
912 * our fake data. Substitute the fake data with real
915 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
916 x11_saved_data, x11_saved_data_len);
921 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
923 int ret = x11_open_helper(&c->output);
926 /* Start normal processing for the channel. */
927 c->type = SSH_CHANNEL_OPEN;
928 channel_pre_open_13(c, readset, writeset);
929 } else if (ret == -1) {
931 * We have received an X11 connection that has bad
932 * authentication information.
934 logit("X11 connection rejected because of wrong authentication.");
935 buffer_clear(&c->input);
936 buffer_clear(&c->output);
937 channel_close_fd(&c->sock);
939 c->type = SSH_CHANNEL_CLOSED;
940 packet_start(SSH_MSG_CHANNEL_CLOSE);
941 packet_put_int(c->remote_id);
947 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
949 int ret = x11_open_helper(&c->output);
951 /* c->force_drain = 1; */
954 c->type = SSH_CHANNEL_OPEN;
955 channel_pre_open(c, readset, writeset);
956 } else if (ret == -1) {
957 logit("X11 connection rejected because of wrong authentication.");
958 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
960 buffer_clear(&c->input);
962 buffer_clear(&c->output);
963 /* for proto v1, the peer will send an IEOF */
965 chan_write_failed(c);
967 c->type = SSH_CHANNEL_OPEN;
968 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
972 /* try to decode a socks4 header */
975 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
978 u_int len, have, i, found;
984 struct in_addr dest_addr;
987 debug2("channel %d: decode socks4", c->self);
989 have = buffer_len(&c->input);
990 len = sizeof(s4_req);
993 p = buffer_ptr(&c->input);
994 for (found = 0, i = len; i < have; i++) {
1000 /* the peer is probably sending garbage */
1001 debug("channel %d: decode socks4: too long",
1008 buffer_get(&c->input, (char *)&s4_req.version, 1);
1009 buffer_get(&c->input, (char *)&s4_req.command, 1);
1010 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1011 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1012 have = buffer_len(&c->input);
1013 p = buffer_ptr(&c->input);
1015 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1017 fatal("channel %d: decode socks4: len %d > have %d",
1018 c->self, len, have);
1019 strlcpy(username, p, sizeof(username));
1020 buffer_consume(&c->input, len);
1021 buffer_consume(&c->input, 1); /* trailing '\0' */
1023 host = inet_ntoa(s4_req.dest_addr);
1024 strlcpy(c->path, host, sizeof(c->path));
1025 c->host_port = ntohs(s4_req.dest_port);
1027 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1028 c->self, host, c->host_port, s4_req.command);
1030 if (s4_req.command != 1) {
1031 debug("channel %d: cannot handle: socks4 cn %d",
1032 c->self, s4_req.command);
1035 s4_rsp.version = 0; /* vn: 0 for reply */
1036 s4_rsp.command = 90; /* cd: req granted */
1037 s4_rsp.dest_port = 0; /* ignored */
1038 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1039 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1043 /* try to decode a socks5 header */
1044 #define SSH_SOCKS5_AUTHDONE 0x1000
1045 #define SSH_SOCKS5_NOAUTH 0x00
1046 #define SSH_SOCKS5_IPV4 0x01
1047 #define SSH_SOCKS5_DOMAIN 0x03
1048 #define SSH_SOCKS5_IPV6 0x04
1049 #define SSH_SOCKS5_CONNECT 0x01
1050 #define SSH_SOCKS5_SUCCESS 0x00
1054 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1062 u_int16_t dest_port;
1063 u_char *p, dest_addr[255+1];
1064 u_int have, need, i, found, nmethods, addrlen, af;
1066 debug2("channel %d: decode socks5", c->self);
1067 p = buffer_ptr(&c->input);
1070 have = buffer_len(&c->input);
1071 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1072 /* format: ver | nmethods | methods */
1076 if (have < nmethods + 2)
1078 /* look for method: "NO AUTHENTICATION REQUIRED" */
1079 for (found = 0, i = 2; i < nmethods + 2; i++) {
1080 if (p[i] == SSH_SOCKS5_NOAUTH) {
1086 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1090 buffer_consume(&c->input, nmethods + 2);
1091 buffer_put_char(&c->output, 0x05); /* version */
1092 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1093 FD_SET(c->sock, writeset);
1094 c->flags |= SSH_SOCKS5_AUTHDONE;
1095 debug2("channel %d: socks5 auth done", c->self);
1096 return 0; /* need more */
1098 debug2("channel %d: socks5 post auth", c->self);
1099 if (have < sizeof(s5_req)+1)
1100 return 0; /* need more */
1101 memcpy(&s5_req, p, sizeof(s5_req));
1102 if (s5_req.version != 0x05 ||
1103 s5_req.command != SSH_SOCKS5_CONNECT ||
1104 s5_req.reserved != 0x00) {
1105 debug2("channel %d: only socks5 connect supported", c->self);
1108 switch (s5_req.atyp){
1109 case SSH_SOCKS5_IPV4:
1113 case SSH_SOCKS5_DOMAIN:
1114 addrlen = p[sizeof(s5_req)];
1117 case SSH_SOCKS5_IPV6:
1122 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1125 need = sizeof(s5_req) + addrlen + 2;
1126 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1130 buffer_consume(&c->input, sizeof(s5_req));
1131 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1132 buffer_consume(&c->input, 1); /* host string length */
1133 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1134 buffer_get(&c->input, (char *)&dest_port, 2);
1135 dest_addr[addrlen] = '\0';
1136 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1137 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1138 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1140 c->host_port = ntohs(dest_port);
1142 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1143 c->self, c->path, c->host_port, s5_req.command);
1145 s5_rsp.version = 0x05;
1146 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1147 s5_rsp.reserved = 0; /* ignored */
1148 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1149 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1150 dest_port = 0; /* ignored */
1152 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1153 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1154 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1158 /* dynamic port forwarding */
1160 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1166 have = buffer_len(&c->input);
1168 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1169 /* buffer_dump(&c->input); */
1170 /* check if the fixed size part of the packet is in buffer. */
1173 FD_SET(c->sock, readset);
1176 /* try to guess the protocol */
1177 p = buffer_ptr(&c->input);
1180 ret = channel_decode_socks4(c, readset, writeset);
1183 ret = channel_decode_socks5(c, readset, writeset);
1191 } else if (ret == 0) {
1192 debug2("channel %d: pre_dynamic: need more", c->self);
1194 FD_SET(c->sock, readset);
1196 /* switch to the next state */
1197 c->type = SSH_CHANNEL_OPENING;
1198 port_open_helper(c, "direct-tcpip");
1202 /* This is our fake X11 server socket. */
1205 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1208 struct sockaddr addr;
1211 char buf[16384], *remote_ipaddr;
1214 if (FD_ISSET(c->sock, readset)) {
1215 debug("X11 connection requested.");
1216 addrlen = sizeof(addr);
1217 newsock = accept(c->sock, &addr, &addrlen);
1218 if (c->single_connection) {
1219 debug2("single_connection: closing X11 listener.");
1220 channel_close_fd(&c->sock);
1224 error("accept: %.100s", strerror(errno));
1227 set_nodelay(newsock);
1228 remote_ipaddr = get_peer_ipaddr(newsock);
1229 remote_port = get_peer_port(newsock);
1230 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1231 remote_ipaddr, remote_port);
1233 nc = channel_new("accepted x11 socket",
1234 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1235 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1237 packet_start(SSH2_MSG_CHANNEL_OPEN);
1238 packet_put_cstring("x11");
1239 packet_put_int(nc->self);
1240 packet_put_int(nc->local_window_max);
1241 packet_put_int(nc->local_maxpacket);
1242 /* originator ipaddr and port */
1243 packet_put_cstring(remote_ipaddr);
1244 if (datafellows & SSH_BUG_X11FWD) {
1245 debug2("ssh2 x11 bug compat mode");
1247 packet_put_int(remote_port);
1251 packet_start(SSH_SMSG_X11_OPEN);
1252 packet_put_int(nc->self);
1253 if (packet_get_protocol_flags() &
1254 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1255 packet_put_cstring(buf);
1258 xfree(remote_ipaddr);
1263 port_open_helper(Channel *c, char *rtype)
1267 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1268 int remote_port = get_peer_port(c->sock);
1270 direct = (strcmp(rtype, "direct-tcpip") == 0);
1272 snprintf(buf, sizeof buf,
1273 "%s: listening port %d for %.100s port %d, "
1274 "connect from %.200s port %d",
1275 rtype, c->listening_port, c->path, c->host_port,
1276 remote_ipaddr, remote_port);
1278 xfree(c->remote_name);
1279 c->remote_name = xstrdup(buf);
1282 packet_start(SSH2_MSG_CHANNEL_OPEN);
1283 packet_put_cstring(rtype);
1284 packet_put_int(c->self);
1285 packet_put_int(c->local_window_max);
1286 packet_put_int(c->local_maxpacket);
1288 /* target host, port */
1289 packet_put_cstring(c->path);
1290 packet_put_int(c->host_port);
1292 /* listen address, port */
1293 packet_put_cstring(c->path);
1294 packet_put_int(c->listening_port);
1296 /* originator host and port */
1297 packet_put_cstring(remote_ipaddr);
1298 packet_put_int((u_int)remote_port);
1301 packet_start(SSH_MSG_PORT_OPEN);
1302 packet_put_int(c->self);
1303 packet_put_cstring(c->path);
1304 packet_put_int(c->host_port);
1305 if (packet_get_protocol_flags() &
1306 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1307 packet_put_cstring(c->remote_name);
1310 xfree(remote_ipaddr);
1314 channel_set_reuseaddr(int fd)
1319 * Set socket options.
1320 * Allow local port reuse in TIME_WAIT.
1322 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1323 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1327 * This socket is listening for connections to a forwarded TCP/IP port.
1331 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1334 struct sockaddr addr;
1335 int newsock, nextstate;
1339 if (FD_ISSET(c->sock, readset)) {
1340 debug("Connection to port %d forwarding "
1341 "to %.100s port %d requested.",
1342 c->listening_port, c->path, c->host_port);
1344 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1345 nextstate = SSH_CHANNEL_OPENING;
1346 rtype = "forwarded-tcpip";
1348 if (c->host_port == 0) {
1349 nextstate = SSH_CHANNEL_DYNAMIC;
1350 rtype = "dynamic-tcpip";
1352 nextstate = SSH_CHANNEL_OPENING;
1353 rtype = "direct-tcpip";
1357 addrlen = sizeof(addr);
1358 newsock = accept(c->sock, &addr, &addrlen);
1360 error("accept: %.100s", strerror(errno));
1363 set_nodelay(newsock);
1364 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1365 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1366 nc->listening_port = c->listening_port;
1367 nc->host_port = c->host_port;
1368 strlcpy(nc->path, c->path, sizeof(nc->path));
1370 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1372 * do not call the channel_post handler until
1373 * this flag has been reset by a pre-handler.
1374 * otherwise the FD_ISSET calls might overflow
1378 port_open_helper(nc, rtype);
1384 * This is the authentication agent socket listening for connections from
1389 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1393 struct sockaddr addr;
1396 if (FD_ISSET(c->sock, readset)) {
1397 addrlen = sizeof(addr);
1398 newsock = accept(c->sock, &addr, &addrlen);
1400 error("accept from auth socket: %.100s", strerror(errno));
1403 nc = channel_new("accepted auth socket",
1404 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1405 c->local_window_max, c->local_maxpacket,
1406 0, "accepted auth socket", 1);
1408 packet_start(SSH2_MSG_CHANNEL_OPEN);
1409 packet_put_cstring("auth-agent@openssh.com");
1410 packet_put_int(nc->self);
1411 packet_put_int(c->local_window_max);
1412 packet_put_int(c->local_maxpacket);
1414 packet_start(SSH_SMSG_AGENT_OPEN);
1415 packet_put_int(nc->self);
1423 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1426 socklen_t sz = sizeof(err);
1428 if (FD_ISSET(c->sock, writeset)) {
1429 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1431 error("getsockopt SO_ERROR failed");
1434 debug("channel %d: connected", c->self);
1435 c->type = SSH_CHANNEL_OPEN;
1437 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1438 packet_put_int(c->remote_id);
1439 packet_put_int(c->self);
1440 packet_put_int(c->local_window);
1441 packet_put_int(c->local_maxpacket);
1443 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1444 packet_put_int(c->remote_id);
1445 packet_put_int(c->self);
1448 debug("channel %d: not connected: %s",
1449 c->self, strerror(err));
1451 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1452 packet_put_int(c->remote_id);
1453 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1454 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1455 packet_put_cstring(strerror(err));
1456 packet_put_cstring("");
1459 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1460 packet_put_int(c->remote_id);
1470 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1472 char buf[CHAN_RBUF];
1475 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1476 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1478 len = read(c->rfd, buf, sizeof(buf));
1479 if (len < 0 && (errno == EINTR || (errno == EAGAIN && !force)))
1481 #ifndef PTY_ZEROREAD
1484 if ((!c->isatty && len <= 0) ||
1485 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1487 debug2("channel %d: read<=0 rfd %d len %d",
1488 c->self, c->rfd, len);
1489 if (c->type != SSH_CHANNEL_OPEN) {
1490 debug2("channel %d: not open", c->self);
1493 } else if (compat13) {
1494 buffer_clear(&c->output);
1495 c->type = SSH_CHANNEL_INPUT_DRAINING;
1496 debug2("channel %d: input draining.", c->self);
1498 chan_read_failed(c);
1502 if (c->input_filter != NULL) {
1503 if (c->input_filter(c, buf, len) == -1) {
1504 debug2("channel %d: filter stops", c->self);
1505 chan_read_failed(c);
1507 } else if (c->datagram) {
1508 buffer_put_string(&c->input, buf, len);
1510 buffer_append(&c->input, buf, len);
1518 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1521 u_char *data = NULL, *buf;
1525 /* Send buffered output data to the socket. */
1527 FD_ISSET(c->wfd, writeset) &&
1528 buffer_len(&c->output) > 0) {
1529 if (c->output_filter != NULL) {
1530 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1531 debug2("channel %d: filter stops", c->self);
1532 if (c->type != SSH_CHANNEL_OPEN)
1535 chan_write_failed(c);
1538 } else if (c->datagram) {
1539 buf = data = buffer_get_string(&c->output, &dlen);
1541 buf = data = buffer_ptr(&c->output);
1542 dlen = buffer_len(&c->output);
1546 /* ignore truncated writes, datagrams might get lost */
1547 c->local_consumed += dlen + 4;
1548 len = write(c->wfd, buf, dlen);
1550 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1553 if (c->type != SSH_CHANNEL_OPEN)
1556 chan_write_failed(c);
1562 /* XXX: Later AIX versions can't push as much data to tty */
1563 if (compat20 && c->wfd_isatty)
1564 dlen = MIN(dlen, 8*1024);
1567 len = write(c->wfd, buf, dlen);
1568 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1571 if (c->type != SSH_CHANNEL_OPEN) {
1572 debug2("channel %d: not open", c->self);
1575 } else if (compat13) {
1576 buffer_clear(&c->output);
1577 debug2("channel %d: input draining.", c->self);
1578 c->type = SSH_CHANNEL_INPUT_DRAINING;
1580 chan_write_failed(c);
1584 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1585 if (tcgetattr(c->wfd, &tio) == 0 &&
1586 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1588 * Simulate echo to reduce the impact of
1589 * traffic analysis. We need to match the
1590 * size of a SSH2_MSG_CHANNEL_DATA message
1591 * (4 byte channel id + buf)
1593 packet_send_ignore(4 + len);
1597 buffer_consume(&c->output, len);
1598 if (compat20 && len > 0) {
1599 c->local_consumed += len;
1606 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1608 char buf[CHAN_RBUF];
1611 /** XXX handle drain efd, too */
1613 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1614 FD_ISSET(c->efd, writeset) &&
1615 buffer_len(&c->extended) > 0) {
1616 len = write(c->efd, buffer_ptr(&c->extended),
1617 buffer_len(&c->extended));
1618 debug2("channel %d: written %d to efd %d",
1619 c->self, len, c->efd);
1620 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1623 debug2("channel %d: closing write-efd %d",
1625 channel_close_fd(&c->efd);
1627 buffer_consume(&c->extended, len);
1628 c->local_consumed += len;
1630 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1631 (c->detach_close || FD_ISSET(c->efd, readset))) {
1632 len = read(c->efd, buf, sizeof(buf));
1633 debug2("channel %d: read %d from efd %d",
1634 c->self, len, c->efd);
1635 if (len < 0 && (errno == EINTR ||
1636 (errno == EAGAIN && !c->detach_close)))
1639 debug2("channel %d: closing read-efd %d",
1641 channel_close_fd(&c->efd);
1643 buffer_append(&c->extended, buf, len);
1652 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1657 /* Monitor control fd to detect if the slave client exits */
1658 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1659 len = read(c->ctl_fd, buf, sizeof(buf));
1660 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1663 debug2("channel %d: ctl read<=0", c->self);
1664 if (c->type != SSH_CHANNEL_OPEN) {
1665 debug2("channel %d: not open", c->self);
1669 chan_read_failed(c);
1670 chan_write_failed(c);
1674 fatal("%s: unexpected data on ctl fd", __func__);
1680 channel_check_window(Channel *c)
1682 if (c->type == SSH_CHANNEL_OPEN &&
1683 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1684 ((c->local_window_max - c->local_window >
1685 c->local_maxpacket*3) ||
1686 c->local_window < c->local_window_max/2) &&
1687 c->local_consumed > 0) {
1689 /* adjust max window size if we are in a dynamic environment */
1690 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1691 addition = c->tcpwinsz - c->local_window_max;
1692 c->local_window_max += addition;
1694 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1695 packet_put_int(c->remote_id);
1696 packet_put_int(c->local_consumed + addition);
1698 debug2("channel %d: window %d sent adjust %d",
1699 c->self, c->local_window,
1701 c->local_window += c->local_consumed + addition;
1702 c->local_consumed = 0;
1708 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1712 channel_handle_rfd(c, readset, writeset);
1713 channel_handle_wfd(c, readset, writeset);
1716 channel_handle_efd(c, readset, writeset);
1717 channel_handle_ctl(c, readset, writeset);
1718 channel_check_window(c);
1723 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1727 /* Send buffered output data to the socket. */
1728 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1729 len = write(c->sock, buffer_ptr(&c->output),
1730 buffer_len(&c->output));
1732 buffer_clear(&c->output);
1734 buffer_consume(&c->output, len);
1739 channel_handler_init_20(void)
1741 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1742 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1743 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1744 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1745 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1746 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1747 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1748 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1750 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1751 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1752 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1753 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1754 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1755 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1756 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1760 channel_handler_init_13(void)
1762 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1763 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1764 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1765 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1766 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1767 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1768 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1769 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1770 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1772 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1773 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1774 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1775 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1776 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1777 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1778 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1782 channel_handler_init_15(void)
1784 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1785 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1786 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1787 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1788 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1789 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1790 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1792 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1793 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1794 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1795 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1796 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1797 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1801 channel_handler_init(void)
1805 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1806 channel_pre[i] = NULL;
1807 channel_post[i] = NULL;
1810 channel_handler_init_20();
1812 channel_handler_init_13();
1814 channel_handler_init_15();
1817 /* gc dead channels */
1819 channel_garbage_collect(Channel *c)
1823 if (c->detach_user != NULL) {
1824 if (!chan_is_dead(c, c->detach_close))
1826 debug2("channel %d: gc: notify user", c->self);
1827 c->detach_user(c->self, NULL);
1828 /* if we still have a callback */
1829 if (c->detach_user != NULL)
1831 debug2("channel %d: gc: user detached", c->self);
1833 if (!chan_is_dead(c, 1))
1835 debug2("channel %d: garbage collecting", c->self);
1840 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1842 static int did_init = 0;
1847 channel_handler_init();
1850 for (i = 0; i < channels_alloc; i++) {
1854 if (ftab[c->type] != NULL)
1855 (*ftab[c->type])(c, readset, writeset);
1856 channel_garbage_collect(c);
1861 * Allocate/update select bitmasks and add any bits relevant to channels in
1865 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1866 u_int *nallocp, int rekeying)
1868 u_int n, sz, nfdset;
1870 n = MAX(*maxfdp, channel_max_fd);
1872 nfdset = howmany(n+1, NFDBITS);
1873 /* Explicitly test here, because xrealloc isn't always called */
1874 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1875 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1876 sz = nfdset * sizeof(fd_mask);
1878 /* perhaps check sz < nalloc/2 and shrink? */
1879 if (*readsetp == NULL || sz > *nallocp) {
1880 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1881 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1885 memset(*readsetp, 0, sz);
1886 memset(*writesetp, 0, sz);
1889 channel_handler(channel_pre, *readsetp, *writesetp);
1893 * After select, perform any appropriate operations for channels which have
1897 channel_after_select(fd_set *readset, fd_set *writeset)
1899 channel_handler(channel_post, readset, writeset);
1903 /* If there is data to send to the connection, enqueue some of it now. */
1905 channel_output_poll(void)
1910 for (i = 0; i < channels_alloc; i++) {
1916 * We are only interested in channels that can have buffered
1920 if (c->type != SSH_CHANNEL_OPEN &&
1921 c->type != SSH_CHANNEL_INPUT_DRAINING)
1924 if (c->type != SSH_CHANNEL_OPEN)
1928 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1929 /* XXX is this true? */
1930 debug3("channel %d: will not send data after close", c->self);
1934 /* Get the amount of buffered data for this channel. */
1935 if ((c->istate == CHAN_INPUT_OPEN ||
1936 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1937 (len = buffer_len(&c->input)) > 0) {
1943 data = buffer_get_string(&c->input,
1945 packet_start(SSH2_MSG_CHANNEL_DATA);
1946 packet_put_int(c->remote_id);
1947 packet_put_string(data, dlen);
1949 c->remote_window -= dlen + 4;
1955 * Send some data for the other side over the secure
1959 if (len > c->remote_window)
1960 len = c->remote_window;
1961 if (len > c->remote_maxpacket)
1962 len = c->remote_maxpacket;
1964 if (packet_is_interactive()) {
1968 /* Keep the packets at reasonable size. */
1969 if (len > packet_get_maxsize()/2)
1970 len = packet_get_maxsize()/2;
1974 packet_start(compat20 ?
1975 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1976 packet_put_int(c->remote_id);
1977 packet_put_string(buffer_ptr(&c->input), len);
1979 buffer_consume(&c->input, len);
1980 c->remote_window -= len;
1982 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1984 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1986 * input-buffer is empty and read-socket shutdown:
1987 * tell peer, that we will not send more data: send IEOF.
1988 * hack for extended data: delay EOF if EFD still in use.
1990 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1991 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1992 c->self, c->efd, buffer_len(&c->extended));
1996 /* Send extended data, i.e. stderr */
1998 !(c->flags & CHAN_EOF_SENT) &&
1999 c->remote_window > 0 &&
2000 (len = buffer_len(&c->extended)) > 0 &&
2001 c->extended_usage == CHAN_EXTENDED_READ) {
2002 debug2("channel %d: rwin %u elen %u euse %d",
2003 c->self, c->remote_window, buffer_len(&c->extended),
2005 if (len > c->remote_window)
2006 len = c->remote_window;
2007 if (len > c->remote_maxpacket)
2008 len = c->remote_maxpacket;
2009 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2010 packet_put_int(c->remote_id);
2011 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2012 packet_put_string(buffer_ptr(&c->extended), len);
2014 buffer_consume(&c->extended, len);
2015 c->remote_window -= len;
2016 debug2("channel %d: sent ext data %d", c->self, len);
2022 /* -- protocol input */
2026 channel_input_data(int type, u_int32_t seq, void *ctxt)
2033 /* Get the channel number and verify it. */
2034 id = packet_get_int();
2035 c = channel_lookup(id);
2037 packet_disconnect("Received data for nonexistent channel %d.", id);
2039 /* Ignore any data for non-open channels (might happen on close) */
2040 if (c->type != SSH_CHANNEL_OPEN &&
2041 c->type != SSH_CHANNEL_X11_OPEN)
2045 data = packet_get_string(&data_len);
2048 * Ignore data for protocol > 1.3 if output end is no longer open.
2049 * For protocol 2 the sending side is reducing its window as it sends
2050 * data, so we must 'fake' consumption of the data in order to ensure
2051 * that window updates are sent back. Otherwise the connection might
2054 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2056 c->local_window -= data_len;
2057 c->local_consumed += data_len;
2064 if (data_len > c->local_maxpacket) {
2065 logit("channel %d: rcvd big packet %d, maxpack %d",
2066 c->self, data_len, c->local_maxpacket);
2068 if (data_len > c->local_window) {
2069 logit("channel %d: rcvd too much data %d, win %d",
2070 c->self, data_len, c->local_window);
2074 c->local_window -= data_len;
2078 buffer_put_string(&c->output, data, data_len);
2080 buffer_append(&c->output, data, data_len);
2086 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2090 u_int data_len, tcode;
2093 /* Get the channel number and verify it. */
2094 id = packet_get_int();
2095 c = channel_lookup(id);
2098 packet_disconnect("Received extended_data for bad channel %d.", id);
2099 if (c->type != SSH_CHANNEL_OPEN) {
2100 logit("channel %d: ext data for non open", id);
2103 if (c->flags & CHAN_EOF_RCVD) {
2104 if (datafellows & SSH_BUG_EXTEOF)
2105 debug("channel %d: accepting ext data after eof", id);
2107 packet_disconnect("Received extended_data after EOF "
2108 "on channel %d.", id);
2110 tcode = packet_get_int();
2112 c->extended_usage != CHAN_EXTENDED_WRITE ||
2113 tcode != SSH2_EXTENDED_DATA_STDERR) {
2114 logit("channel %d: bad ext data", c->self);
2117 data = packet_get_string(&data_len);
2119 if (data_len > c->local_window) {
2120 logit("channel %d: rcvd too much extended_data %d, win %d",
2121 c->self, data_len, c->local_window);
2125 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2126 c->local_window -= data_len;
2127 buffer_append(&c->extended, data, data_len);
2133 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2138 id = packet_get_int();
2140 c = channel_lookup(id);
2142 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2145 /* XXX force input close */
2146 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2147 debug("channel %d: FORCE input drain", c->self);
2148 c->istate = CHAN_INPUT_WAIT_DRAIN;
2149 if (buffer_len(&c->input) == 0)
2157 channel_input_close(int type, u_int32_t seq, void *ctxt)
2162 id = packet_get_int();
2164 c = channel_lookup(id);
2166 packet_disconnect("Received close for nonexistent channel %d.", id);
2169 * Send a confirmation that we have closed the channel and no more
2170 * data is coming for it.
2172 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2173 packet_put_int(c->remote_id);
2177 * If the channel is in closed state, we have sent a close request,
2178 * and the other side will eventually respond with a confirmation.
2179 * Thus, we cannot free the channel here, because then there would be
2180 * no-one to receive the confirmation. The channel gets freed when
2181 * the confirmation arrives.
2183 if (c->type != SSH_CHANNEL_CLOSED) {
2185 * Not a closed channel - mark it as draining, which will
2186 * cause it to be freed later.
2188 buffer_clear(&c->input);
2189 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2193 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2196 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2198 int id = packet_get_int();
2199 Channel *c = channel_lookup(id);
2203 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2204 chan_rcvd_oclose(c);
2209 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2211 int id = packet_get_int();
2212 Channel *c = channel_lookup(id);
2216 packet_disconnect("Received close confirmation for "
2217 "out-of-range channel %d.", id);
2218 if (c->type != SSH_CHANNEL_CLOSED)
2219 packet_disconnect("Received close confirmation for "
2220 "non-closed channel %d (type %d).", id, c->type);
2226 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2231 id = packet_get_int();
2232 c = channel_lookup(id);
2234 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2235 packet_disconnect("Received open confirmation for "
2236 "non-opening channel %d.", id);
2237 remote_id = packet_get_int();
2238 /* Record the remote channel number and mark that the channel is now open. */
2239 c->remote_id = remote_id;
2240 c->type = SSH_CHANNEL_OPEN;
2243 c->remote_window = packet_get_int();
2244 c->remote_maxpacket = packet_get_int();
2246 debug2("callback start");
2247 c->confirm(c->self, c->confirm_ctx);
2248 debug2("callback done");
2250 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2251 c->remote_window, c->remote_maxpacket);
2257 reason2txt(int reason)
2260 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2261 return "administratively prohibited";
2262 case SSH2_OPEN_CONNECT_FAILED:
2263 return "connect failed";
2264 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2265 return "unknown channel type";
2266 case SSH2_OPEN_RESOURCE_SHORTAGE:
2267 return "resource shortage";
2269 return "unknown reason";
2274 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2277 char *msg = NULL, *lang = NULL;
2280 id = packet_get_int();
2281 c = channel_lookup(id);
2283 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2284 packet_disconnect("Received open failure for "
2285 "non-opening channel %d.", id);
2287 reason = packet_get_int();
2288 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2289 msg = packet_get_string(NULL);
2290 lang = packet_get_string(NULL);
2292 logit("channel %d: open failed: %s%s%s", id,
2293 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2300 /* Free the channel. This will also close the socket. */
2306 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2315 /* Get the channel number and verify it. */
2316 id = packet_get_int();
2317 c = channel_lookup(id);
2320 logit("Received window adjust for non-open channel %d.", id);
2323 adjust = packet_get_int();
2325 debug2("channel %d: rcvd adjust %u", id, adjust);
2326 c->remote_window += adjust;
2331 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2335 char *host, *originator_string;
2336 int remote_id, sock = -1;
2338 remote_id = packet_get_int();
2339 host = packet_get_string(NULL);
2340 host_port = packet_get_int();
2342 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2343 originator_string = packet_get_string(NULL);
2345 originator_string = xstrdup("unknown (remote did not supply name)");
2348 sock = channel_connect_to(host, host_port);
2350 c = channel_new("connected socket",
2351 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2352 originator_string, 1);
2353 c->remote_id = remote_id;
2355 xfree(originator_string);
2357 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2358 packet_put_int(remote_id);
2365 /* -- tcp forwarding */
2368 channel_set_af(int af)
2374 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2375 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2376 int hpn_disabled, int hpn_buffer_size)
2379 int sock, r, success = 0, wildcard = 0, is_client;
2380 struct addrinfo hints, *ai, *aitop;
2381 const char *host, *addr;
2382 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2384 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2385 listen_addr : host_to_connect;
2386 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2389 error("No forward host name.");
2392 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2393 error("Forward host name too long.");
2398 * Determine whether or not a port forward listens to loopback,
2399 * specified address or wildcard. On the client, a specified bind
2400 * address will always override gateway_ports. On the server, a
2401 * gateway_ports of 1 (``yes'') will override the client's
2402 * specification and force a wildcard bind, whereas a value of 2
2403 * (``clientspecified'') will bind to whatever address the client
2406 * Special-case listen_addrs are:
2408 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2409 * "" (empty string), "*" -> wildcard v4/v6
2410 * "localhost" -> loopback v4/v6
2413 if (listen_addr == NULL) {
2414 /* No address specified: default to gateway_ports setting */
2417 } else if (gateway_ports || is_client) {
2418 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2419 strcmp(listen_addr, "0.0.0.0") == 0) ||
2420 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2421 (!is_client && gateway_ports == 1))
2423 else if (strcmp(listen_addr, "localhost") != 0)
2427 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2428 type, wildcard, (addr == NULL) ? "NULL" : addr);
2431 * getaddrinfo returns a loopback address if the hostname is
2432 * set to NULL and hints.ai_flags is not AI_PASSIVE
2434 memset(&hints, 0, sizeof(hints));
2435 hints.ai_family = IPv4or6;
2436 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2437 hints.ai_socktype = SOCK_STREAM;
2438 snprintf(strport, sizeof strport, "%d", listen_port);
2439 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2441 /* This really shouldn't happen */
2442 packet_disconnect("getaddrinfo: fatal error: %s",
2445 error("channel_setup_fwd_listener: "
2446 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2451 for (ai = aitop; ai; ai = ai->ai_next) {
2452 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2454 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2455 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2456 error("channel_setup_fwd_listener: getnameinfo failed");
2459 /* Create a port to listen for the host. */
2460 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2462 /* this is no error since kernel may not support ipv6 */
2463 verbose("socket: %.100s", strerror(errno));
2467 channel_set_reuseaddr(sock);
2469 debug("Local forwarding listening on %s port %s.", ntop, strport);
2471 /* Bind the socket to the address. */
2472 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2473 /* address can be in use ipv6 address is already bound */
2475 error("bind: %.100s", strerror(errno));
2477 verbose("bind: %.100s", strerror(errno));
2482 /* Start listening for connections on the socket. */
2483 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2484 error("listen: %.100s", strerror(errno));
2488 /* Allocate a channel number for the socket. */
2489 /* explicitly test for hpn disabled option. if true use smaller window size */
2491 c = channel_new("port listener", type, sock, sock, -1,
2492 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2493 0, "port listener", 1);
2495 c = channel_new("port listener", type, sock, sock, -1,
2496 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2497 0, "port listener", 1);
2498 strlcpy(c->path, host, sizeof(c->path));
2499 c->host_port = port_to_connect;
2500 c->listening_port = listen_port;
2504 error("channel_setup_fwd_listener: cannot listen to port: %d",
2506 freeaddrinfo(aitop);
2511 channel_cancel_rport_listener(const char *host, u_short port)
2516 for (i = 0; i < channels_alloc; i++) {
2517 Channel *c = channels[i];
2519 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2520 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2521 c->listening_port == port) {
2522 debug2("%s: close channel %d", __func__, i);
2531 /* protocol local port fwd, used by ssh (and sshd in v1) */
2533 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2534 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2535 int hpn_disabled, int hpn_buffer_size)
2537 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2538 listen_host, listen_port, host_to_connect, port_to_connect,
2539 gateway_ports, hpn_disabled, hpn_buffer_size);
2542 /* protocol v2 remote port fwd, used by sshd */
2544 channel_setup_remote_fwd_listener(const char *listen_address,
2545 u_short listen_port, int gateway_ports, int hpn_disabled, int hpn_buffer_size)
2547 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2548 listen_address, listen_port, NULL, 0, gateway_ports,
2549 hpn_disabled, hpn_buffer_size);
2553 * Initiate forwarding of connections to port "port" on remote host through
2554 * the secure channel to host:port from local side.
2558 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2559 const char *host_to_connect, u_short port_to_connect)
2561 int type, success = 0;
2563 /* Record locally that connection to this host/port is permitted. */
2564 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2565 fatal("channel_request_remote_forwarding: too many forwards");
2567 /* Send the forward request to the remote side. */
2569 const char *address_to_bind;
2570 if (listen_host == NULL) {
2571 if (datafellows & SSH_BUG_RFWD_ADDR)
2572 address_to_bind = "127.0.0.1";
2574 address_to_bind = "localhost";
2575 } else if (*listen_host == '\0' ||
2576 strcmp(listen_host, "*") == 0) {
2577 if (datafellows & SSH_BUG_RFWD_ADDR)
2578 address_to_bind = "0.0.0.0";
2580 address_to_bind = "";
2582 address_to_bind = listen_host;
2584 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2585 packet_put_cstring("tcpip-forward");
2586 packet_put_char(1); /* boolean: want reply */
2587 packet_put_cstring(address_to_bind);
2588 packet_put_int(listen_port);
2590 packet_write_wait();
2591 /* Assume that server accepts the request */
2594 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2595 packet_put_int(listen_port);
2596 packet_put_cstring(host_to_connect);
2597 packet_put_int(port_to_connect);
2599 packet_write_wait();
2601 /* Wait for response from the remote side. */
2602 type = packet_read();
2604 case SSH_SMSG_SUCCESS:
2607 case SSH_SMSG_FAILURE:
2610 /* Unknown packet */
2611 packet_disconnect("Protocol error for port forward request:"
2612 "received packet type %d.", type);
2616 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2617 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2618 permitted_opens[num_permitted_opens].listen_port = listen_port;
2619 num_permitted_opens++;
2621 return (success ? 0 : -1);
2625 * Request cancellation of remote forwarding of connection host:port from
2629 channel_request_rforward_cancel(const char *host, u_short port)
2636 for (i = 0; i < num_permitted_opens; i++) {
2637 if (permitted_opens[i].host_to_connect != NULL &&
2638 permitted_opens[i].listen_port == port)
2641 if (i >= num_permitted_opens) {
2642 debug("%s: requested forward not found", __func__);
2645 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2646 packet_put_cstring("cancel-tcpip-forward");
2648 packet_put_cstring(host == NULL ? "" : host);
2649 packet_put_int(port);
2652 permitted_opens[i].listen_port = 0;
2653 permitted_opens[i].port_to_connect = 0;
2654 xfree(permitted_opens[i].host_to_connect);
2655 permitted_opens[i].host_to_connect = NULL;
2659 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2660 * listening for the port, and sends back a success reply (or disconnect
2661 * message if there was an error).
2664 channel_input_port_forward_request(int is_root, int gateway_ports,
2665 int hpn_disabled, int hpn_buffer_size)
2667 u_short port, host_port;
2671 /* Get arguments from the packet. */
2672 port = packet_get_int();
2673 hostname = packet_get_string(NULL);
2674 host_port = packet_get_int();
2678 * Check that an unprivileged user is not trying to forward a
2681 if (port < IPPORT_RESERVED && !is_root)
2683 "Requested forwarding of port %d but user is not root.",
2686 packet_disconnect("Dynamic forwarding denied.");
2689 /* Initiate forwarding */
2690 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2691 host_port, gateway_ports, hpn_disabled, hpn_buffer_size);
2693 /* Free the argument string. */
2696 return (success ? 0 : -1);
2700 * Permits opening to any host/port if permitted_opens[] is empty. This is
2701 * usually called by the server, because the user could connect to any port
2702 * anyway, and the server has no way to know but to trust the client anyway.
2705 channel_permit_all_opens(void)
2707 if (num_permitted_opens == 0)
2708 all_opens_permitted = 1;
2712 channel_add_permitted_opens(char *host, int port)
2714 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2715 fatal("channel_add_permitted_opens: too many forwards");
2716 debug("allow port forwarding to host %s port %d", host, port);
2718 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2719 permitted_opens[num_permitted_opens].port_to_connect = port;
2720 num_permitted_opens++;
2722 all_opens_permitted = 0;
2726 channel_add_adm_permitted_opens(char *host, int port)
2728 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2729 fatal("channel_add_adm_permitted_opens: too many forwards");
2730 debug("config allows port forwarding to host %s port %d", host, port);
2732 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2734 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2735 return ++num_adm_permitted_opens;
2739 channel_clear_permitted_opens(void)
2743 for (i = 0; i < num_permitted_opens; i++)
2744 if (permitted_opens[i].host_to_connect != NULL)
2745 xfree(permitted_opens[i].host_to_connect);
2746 num_permitted_opens = 0;
2750 channel_clear_adm_permitted_opens(void)
2754 for (i = 0; i < num_adm_permitted_opens; i++)
2755 if (permitted_adm_opens[i].host_to_connect != NULL)
2756 xfree(permitted_adm_opens[i].host_to_connect);
2757 num_adm_permitted_opens = 0;
2760 /* return socket to remote host, port */
2762 connect_to(const char *host, u_short port)
2764 struct addrinfo hints, *ai, *aitop;
2765 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2769 memset(&hints, 0, sizeof(hints));
2770 hints.ai_family = IPv4or6;
2771 hints.ai_socktype = SOCK_STREAM;
2772 snprintf(strport, sizeof strport, "%d", port);
2773 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2774 error("connect_to %.100s: unknown host (%s)", host,
2775 gai_strerror(gaierr));
2778 for (ai = aitop; ai; ai = ai->ai_next) {
2779 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2781 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2782 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2783 error("connect_to: getnameinfo failed");
2786 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2788 if (ai->ai_next == NULL)
2789 error("socket: %.100s", strerror(errno));
2791 verbose("socket: %.100s", strerror(errno));
2794 if (set_nonblock(sock) == -1)
2795 fatal("%s: set_nonblock(%d)", __func__, sock);
2796 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2797 errno != EINPROGRESS) {
2798 error("connect_to %.100s port %s: %.100s", ntop, strport,
2801 continue; /* fail -- try next */
2803 break; /* success */
2806 freeaddrinfo(aitop);
2808 error("connect_to %.100s port %d: failed.", host, port);
2817 channel_connect_by_listen_address(u_short listen_port)
2821 for (i = 0; i < num_permitted_opens; i++)
2822 if (permitted_opens[i].host_to_connect != NULL &&
2823 permitted_opens[i].listen_port == listen_port)
2825 permitted_opens[i].host_to_connect,
2826 permitted_opens[i].port_to_connect);
2827 error("WARNING: Server requests forwarding for unknown listen_port %d",
2832 /* Check if connecting to that port is permitted and connect. */
2834 channel_connect_to(const char *host, u_short port)
2836 int i, permit, permit_adm = 1;
2838 permit = all_opens_permitted;
2840 for (i = 0; i < num_permitted_opens; i++)
2841 if (permitted_opens[i].host_to_connect != NULL &&
2842 permitted_opens[i].port_to_connect == port &&
2843 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2847 if (num_adm_permitted_opens > 0) {
2849 for (i = 0; i < num_adm_permitted_opens; i++)
2850 if (permitted_adm_opens[i].host_to_connect != NULL &&
2851 permitted_adm_opens[i].port_to_connect == port &&
2852 strcmp(permitted_adm_opens[i].host_to_connect, host)
2857 if (!permit || !permit_adm) {
2858 logit("Received request to connect to host %.100s port %d, "
2859 "but the request was denied.", host, port);
2862 return connect_to(host, port);
2866 channel_send_window_changes(void)
2871 for (i = 0; i < channels_alloc; i++) {
2872 if (channels[i] == NULL || !channels[i]->client_tty ||
2873 channels[i]->type != SSH_CHANNEL_OPEN)
2875 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2877 channel_request_start(i, "window-change", 0);
2878 packet_put_int((u_int)ws.ws_col);
2879 packet_put_int((u_int)ws.ws_row);
2880 packet_put_int((u_int)ws.ws_xpixel);
2881 packet_put_int((u_int)ws.ws_ypixel);
2886 /* -- X11 forwarding */
2889 * Creates an internet domain socket for listening for X11 connections.
2890 * Returns 0 and a suitable display number for the DISPLAY variable
2891 * stored in display_numberp , or -1 if an error occurs.
2894 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2895 int single_connection, u_int *display_numberp, int **chanids,
2896 int hpn_disabled, int hpn_buffer_size)
2899 int display_number, sock;
2901 struct addrinfo hints, *ai, *aitop;
2902 char strport[NI_MAXSERV];
2903 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2905 if (chanids == NULL)
2908 for (display_number = x11_display_offset;
2909 display_number < MAX_DISPLAYS;
2911 port = 6000 + display_number;
2912 memset(&hints, 0, sizeof(hints));
2913 hints.ai_family = IPv4or6;
2914 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2915 hints.ai_socktype = SOCK_STREAM;
2916 snprintf(strport, sizeof strport, "%d", port);
2917 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2918 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2921 for (ai = aitop; ai; ai = ai->ai_next) {
2922 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2924 sock = socket(ai->ai_family, ai->ai_socktype,
2927 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2928 error("socket: %.100s", strerror(errno));
2929 freeaddrinfo(aitop);
2932 debug("x11_create_display_inet: Socket family %d not supported",
2938 if (ai->ai_family == AF_INET6) {
2940 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2941 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2944 channel_set_reuseaddr(sock);
2945 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2946 debug2("bind port %d: %.100s", port, strerror(errno));
2952 for (n = 0; n < num_socks; n++) {
2958 socks[num_socks++] = sock;
2959 #ifndef DONT_TRY_OTHER_AF
2960 if (num_socks == NUM_SOCKS)
2963 if (x11_use_localhost) {
2964 if (num_socks == NUM_SOCKS)
2971 freeaddrinfo(aitop);
2975 if (display_number >= MAX_DISPLAYS) {
2976 error("Failed to allocate internet-domain X11 display socket.");
2979 /* Start listening for connections on the socket. */
2980 for (n = 0; n < num_socks; n++) {
2982 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2983 error("listen: %.100s", strerror(errno));
2989 /* Allocate a channel for each socket. */
2990 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2991 for (n = 0; n < num_socks; n++) {
2994 nc = channel_new("x11 listener",
2995 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2996 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2997 0, "X11 inet listener", 1);
2999 nc = channel_new("x11 listener",
3000 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3001 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
3002 0, "X11 inet listener", 1);
3003 nc->single_connection = single_connection;
3004 (*chanids)[n] = nc->self;
3008 /* Return the display number for the DISPLAY environment variable. */
3009 *display_numberp = display_number;
3014 connect_local_xsocket(u_int dnr)
3017 struct sockaddr_un addr;
3019 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3021 error("socket: %.100s", strerror(errno));
3022 memset(&addr, 0, sizeof(addr));
3023 addr.sun_family = AF_UNIX;
3024 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
3025 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3028 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3033 x11_connect_display(void)
3035 u_int display_number;
3036 const char *display;
3037 char buf[1024], *cp;
3038 struct addrinfo hints, *ai, *aitop;
3039 char strport[NI_MAXSERV];
3040 int gaierr, sock = 0;
3042 /* Try to open a socket for the local X server. */
3043 display = getenv("DISPLAY");
3045 error("DISPLAY not set.");
3049 * Now we decode the value of the DISPLAY variable and make a
3050 * connection to the real X server.
3054 * Check if it is a unix domain socket. Unix domain displays are in
3055 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3057 if (strncmp(display, "unix:", 5) == 0 ||
3058 display[0] == ':') {
3059 /* Connect to the unix domain socket. */
3060 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3061 error("Could not parse display number from DISPLAY: %.100s",
3065 /* Create a socket. */
3066 sock = connect_local_xsocket(display_number);
3070 /* OK, we now have a connection to the display. */
3074 * Connect to an inet socket. The DISPLAY value is supposedly
3075 * hostname:d[.s], where hostname may also be numeric IP address.
3077 strlcpy(buf, display, sizeof(buf));
3078 cp = strchr(buf, ':');
3080 error("Could not find ':' in DISPLAY: %.100s", display);
3084 /* buf now contains the host name. But first we parse the display number. */
3085 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3086 error("Could not parse display number from DISPLAY: %.100s",
3091 /* Look up the host address */
3092 memset(&hints, 0, sizeof(hints));
3093 hints.ai_family = IPv4or6;
3094 hints.ai_socktype = SOCK_STREAM;
3095 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3096 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3097 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
3100 for (ai = aitop; ai; ai = ai->ai_next) {
3101 /* Create a socket. */
3102 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3104 debug2("socket: %.100s", strerror(errno));
3107 /* Connect it to the display. */
3108 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3109 debug2("connect %.100s port %u: %.100s", buf,
3110 6000 + display_number, strerror(errno));
3117 freeaddrinfo(aitop);
3119 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3128 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3129 * the remote channel number. We should do whatever we want, and respond
3130 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3135 x11_input_open(int type, u_int32_t seq, void *ctxt)
3138 int remote_id, sock = 0;
3141 debug("Received X11 open request.");
3143 remote_id = packet_get_int();
3145 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3146 remote_host = packet_get_string(NULL);
3148 remote_host = xstrdup("unknown (remote did not supply name)");
3152 /* Obtain a connection to the real X display. */
3153 sock = x11_connect_display();
3155 /* Allocate a channel for this connection. */
3156 c = channel_new("connected x11 socket",
3157 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3159 c->remote_id = remote_id;
3164 /* Send refusal to the remote host. */
3165 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3166 packet_put_int(remote_id);
3168 /* Send a confirmation to the remote host. */
3169 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3170 packet_put_int(remote_id);
3171 packet_put_int(c->self);
3176 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3179 deny_input_open(int type, u_int32_t seq, void *ctxt)
3181 int rchan = packet_get_int();
3184 case SSH_SMSG_AGENT_OPEN:
3185 error("Warning: ssh server tried agent forwarding.");
3187 case SSH_SMSG_X11_OPEN:
3188 error("Warning: ssh server tried X11 forwarding.");
3191 error("deny_input_open: type %d", type);
3194 error("Warning: this is probably a break-in attempt by a malicious server.");
3195 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3196 packet_put_int(rchan);
3201 * Requests forwarding of X11 connections, generates fake authentication
3202 * data, and enables authentication spoofing.
3203 * This should be called in the client only.
3206 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3207 const char *proto, const char *data)
3209 u_int data_len = (u_int) strlen(data) / 2;
3216 if (x11_saved_display == NULL)
3217 x11_saved_display = xstrdup(disp);
3218 else if (strcmp(disp, x11_saved_display) != 0) {
3219 error("x11_request_forwarding_with_spoofing: different "
3220 "$DISPLAY already forwarded");
3224 cp = strchr(disp, ':');
3226 cp = strchr(cp, '.');
3228 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3232 if (x11_saved_proto == NULL) {
3233 /* Save protocol name. */
3234 x11_saved_proto = xstrdup(proto);
3236 * Extract real authentication data and generate fake data
3237 * of the same length.
3239 x11_saved_data = xmalloc(data_len);
3240 x11_fake_data = xmalloc(data_len);
3241 for (i = 0; i < data_len; i++) {
3242 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3243 fatal("x11_request_forwarding: bad "
3244 "authentication data: %.100s", data);
3247 x11_saved_data[i] = value;
3248 x11_fake_data[i] = rnd & 0xff;
3251 x11_saved_data_len = data_len;
3252 x11_fake_data_len = data_len;
3255 /* Convert the fake data into hex. */
3256 new_data = tohex(x11_fake_data, data_len);
3258 /* Send the request packet. */
3260 channel_request_start(client_session_id, "x11-req", 0);
3261 packet_put_char(0); /* XXX bool single connection */
3263 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3265 packet_put_cstring(proto);
3266 packet_put_cstring(new_data);
3267 packet_put_int(screen_number);
3269 packet_write_wait();
3274 /* -- agent forwarding */
3276 /* Sends a message to the server to request authentication fd forwarding. */
3279 auth_request_forwarding(void)
3281 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3283 packet_write_wait();