1 /* $OpenBSD: channels.c,v 1.266 2006/08/29 10:40:18 djm 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);
770 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
772 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
774 if (c->istate == CHAN_INPUT_OPEN &&
776 buffer_len(&c->input) < limit &&
777 buffer_check_alloc(&c->input, CHAN_RBUF))
778 FD_SET(c->rfd, readset);
779 if (c->ostate == CHAN_OUTPUT_OPEN ||
780 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
781 if (buffer_len(&c->output) > 0) {
782 FD_SET(c->wfd, writeset);
783 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
784 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
785 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
786 c->self, c->efd, buffer_len(&c->extended));
791 /** XXX check close conditions, too */
792 if (compat20 && c->efd != -1) {
793 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
794 buffer_len(&c->extended) > 0)
795 FD_SET(c->efd, writeset);
796 else if (!(c->flags & CHAN_EOF_SENT) &&
797 c->extended_usage == CHAN_EXTENDED_READ &&
798 buffer_len(&c->extended) < c->remote_window)
799 FD_SET(c->efd, readset);
801 /* XXX: What about efd? races? */
802 if (compat20 && c->ctl_fd != -1 &&
803 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
804 FD_SET(c->ctl_fd, readset);
809 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
811 if (buffer_len(&c->input) == 0) {
812 packet_start(SSH_MSG_CHANNEL_CLOSE);
813 packet_put_int(c->remote_id);
815 c->type = SSH_CHANNEL_CLOSED;
816 debug2("channel %d: closing after input drain.", c->self);
822 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
824 if (buffer_len(&c->output) == 0)
827 FD_SET(c->sock, writeset);
831 * This is a special state for X11 authentication spoofing. An opened X11
832 * connection (when authentication spoofing is being done) remains in this
833 * state until the first packet has been completely read. The authentication
834 * data in that packet is then substituted by the real data if it matches the
835 * fake data, and the channel is put into normal mode.
836 * XXX All this happens at the client side.
837 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
840 x11_open_helper(Buffer *b)
843 u_int proto_len, data_len;
845 /* Check if the fixed size part of the packet is in buffer. */
846 if (buffer_len(b) < 12)
849 /* Parse the lengths of variable-length fields. */
851 if (ucp[0] == 0x42) { /* Byte order MSB first. */
852 proto_len = 256 * ucp[6] + ucp[7];
853 data_len = 256 * ucp[8] + ucp[9];
854 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
855 proto_len = ucp[6] + 256 * ucp[7];
856 data_len = ucp[8] + 256 * ucp[9];
858 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
863 /* Check if the whole packet is in buffer. */
865 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
868 /* Check if authentication protocol matches. */
869 if (proto_len != strlen(x11_saved_proto) ||
870 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
871 debug2("X11 connection uses different authentication protocol.");
874 /* Check if authentication data matches our fake data. */
875 if (data_len != x11_fake_data_len ||
876 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
877 x11_fake_data, x11_fake_data_len) != 0) {
878 debug2("X11 auth data does not match fake data.");
881 /* Check fake data length */
882 if (x11_fake_data_len != x11_saved_data_len) {
883 error("X11 fake_data_len %d != saved_data_len %d",
884 x11_fake_data_len, x11_saved_data_len);
888 * Received authentication protocol and data match
889 * our fake data. Substitute the fake data with real
892 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
893 x11_saved_data, x11_saved_data_len);
898 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
900 int ret = x11_open_helper(&c->output);
903 /* Start normal processing for the channel. */
904 c->type = SSH_CHANNEL_OPEN;
905 channel_pre_open_13(c, readset, writeset);
906 } else if (ret == -1) {
908 * We have received an X11 connection that has bad
909 * authentication information.
911 logit("X11 connection rejected because of wrong authentication.");
912 buffer_clear(&c->input);
913 buffer_clear(&c->output);
914 channel_close_fd(&c->sock);
916 c->type = SSH_CHANNEL_CLOSED;
917 packet_start(SSH_MSG_CHANNEL_CLOSE);
918 packet_put_int(c->remote_id);
924 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
926 int ret = x11_open_helper(&c->output);
928 /* c->force_drain = 1; */
931 c->type = SSH_CHANNEL_OPEN;
932 channel_pre_open(c, readset, writeset);
933 } else if (ret == -1) {
934 logit("X11 connection rejected because of wrong authentication.");
935 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
937 buffer_clear(&c->input);
939 buffer_clear(&c->output);
940 /* for proto v1, the peer will send an IEOF */
942 chan_write_failed(c);
944 c->type = SSH_CHANNEL_OPEN;
945 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
949 /* try to decode a socks4 header */
952 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
955 u_int len, have, i, found;
961 struct in_addr dest_addr;
964 debug2("channel %d: decode socks4", c->self);
966 have = buffer_len(&c->input);
967 len = sizeof(s4_req);
970 p = buffer_ptr(&c->input);
971 for (found = 0, i = len; i < have; i++) {
977 /* the peer is probably sending garbage */
978 debug("channel %d: decode socks4: too long",
985 buffer_get(&c->input, (char *)&s4_req.version, 1);
986 buffer_get(&c->input, (char *)&s4_req.command, 1);
987 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
988 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
989 have = buffer_len(&c->input);
990 p = buffer_ptr(&c->input);
992 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
994 fatal("channel %d: decode socks4: len %d > have %d",
996 strlcpy(username, p, sizeof(username));
997 buffer_consume(&c->input, len);
998 buffer_consume(&c->input, 1); /* trailing '\0' */
1000 host = inet_ntoa(s4_req.dest_addr);
1001 strlcpy(c->path, host, sizeof(c->path));
1002 c->host_port = ntohs(s4_req.dest_port);
1004 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1005 c->self, host, c->host_port, s4_req.command);
1007 if (s4_req.command != 1) {
1008 debug("channel %d: cannot handle: socks4 cn %d",
1009 c->self, s4_req.command);
1012 s4_rsp.version = 0; /* vn: 0 for reply */
1013 s4_rsp.command = 90; /* cd: req granted */
1014 s4_rsp.dest_port = 0; /* ignored */
1015 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1016 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1020 /* try to decode a socks5 header */
1021 #define SSH_SOCKS5_AUTHDONE 0x1000
1022 #define SSH_SOCKS5_NOAUTH 0x00
1023 #define SSH_SOCKS5_IPV4 0x01
1024 #define SSH_SOCKS5_DOMAIN 0x03
1025 #define SSH_SOCKS5_IPV6 0x04
1026 #define SSH_SOCKS5_CONNECT 0x01
1027 #define SSH_SOCKS5_SUCCESS 0x00
1031 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1039 u_int16_t dest_port;
1040 u_char *p, dest_addr[255+1];
1041 u_int have, need, i, found, nmethods, addrlen, af;
1043 debug2("channel %d: decode socks5", c->self);
1044 p = buffer_ptr(&c->input);
1047 have = buffer_len(&c->input);
1048 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1049 /* format: ver | nmethods | methods */
1053 if (have < nmethods + 2)
1055 /* look for method: "NO AUTHENTICATION REQUIRED" */
1056 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1057 if (p[i] == SSH_SOCKS5_NOAUTH) {
1063 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1067 buffer_consume(&c->input, nmethods + 2);
1068 buffer_put_char(&c->output, 0x05); /* version */
1069 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1070 FD_SET(c->sock, writeset);
1071 c->flags |= SSH_SOCKS5_AUTHDONE;
1072 debug2("channel %d: socks5 auth done", c->self);
1073 return 0; /* need more */
1075 debug2("channel %d: socks5 post auth", c->self);
1076 if (have < sizeof(s5_req)+1)
1077 return 0; /* need more */
1078 memcpy(&s5_req, p, sizeof(s5_req));
1079 if (s5_req.version != 0x05 ||
1080 s5_req.command != SSH_SOCKS5_CONNECT ||
1081 s5_req.reserved != 0x00) {
1082 debug2("channel %d: only socks5 connect supported", c->self);
1085 switch (s5_req.atyp){
1086 case SSH_SOCKS5_IPV4:
1090 case SSH_SOCKS5_DOMAIN:
1091 addrlen = p[sizeof(s5_req)];
1094 case SSH_SOCKS5_IPV6:
1099 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1102 need = sizeof(s5_req) + addrlen + 2;
1103 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1107 buffer_consume(&c->input, sizeof(s5_req));
1108 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1109 buffer_consume(&c->input, 1); /* host string length */
1110 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1111 buffer_get(&c->input, (char *)&dest_port, 2);
1112 dest_addr[addrlen] = '\0';
1113 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1114 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1115 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1117 c->host_port = ntohs(dest_port);
1119 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1120 c->self, c->path, c->host_port, s5_req.command);
1122 s5_rsp.version = 0x05;
1123 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1124 s5_rsp.reserved = 0; /* ignored */
1125 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1126 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1127 dest_port = 0; /* ignored */
1129 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1130 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1131 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1135 /* dynamic port forwarding */
1137 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1143 have = buffer_len(&c->input);
1145 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1146 /* buffer_dump(&c->input); */
1147 /* check if the fixed size part of the packet is in buffer. */
1150 FD_SET(c->sock, readset);
1153 /* try to guess the protocol */
1154 p = buffer_ptr(&c->input);
1157 ret = channel_decode_socks4(c, readset, writeset);
1160 ret = channel_decode_socks5(c, readset, writeset);
1168 } else if (ret == 0) {
1169 debug2("channel %d: pre_dynamic: need more", c->self);
1171 FD_SET(c->sock, readset);
1173 /* switch to the next state */
1174 c->type = SSH_CHANNEL_OPENING;
1175 port_open_helper(c, "direct-tcpip");
1179 /* This is our fake X11 server socket. */
1182 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1185 struct sockaddr addr;
1188 char buf[16384], *remote_ipaddr;
1191 if (FD_ISSET(c->sock, readset)) {
1192 debug("X11 connection requested.");
1193 addrlen = sizeof(addr);
1194 newsock = accept(c->sock, &addr, &addrlen);
1195 if (c->single_connection) {
1196 debug2("single_connection: closing X11 listener.");
1197 channel_close_fd(&c->sock);
1201 error("accept: %.100s", strerror(errno));
1204 set_nodelay(newsock);
1205 remote_ipaddr = get_peer_ipaddr(newsock);
1206 remote_port = get_peer_port(newsock);
1207 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1208 remote_ipaddr, remote_port);
1210 nc = channel_new("accepted x11 socket",
1211 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1212 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1214 packet_start(SSH2_MSG_CHANNEL_OPEN);
1215 packet_put_cstring("x11");
1216 packet_put_int(nc->self);
1217 packet_put_int(nc->local_window_max);
1218 packet_put_int(nc->local_maxpacket);
1219 /* originator ipaddr and port */
1220 packet_put_cstring(remote_ipaddr);
1221 if (datafellows & SSH_BUG_X11FWD) {
1222 debug2("ssh2 x11 bug compat mode");
1224 packet_put_int(remote_port);
1228 packet_start(SSH_SMSG_X11_OPEN);
1229 packet_put_int(nc->self);
1230 if (packet_get_protocol_flags() &
1231 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1232 packet_put_cstring(buf);
1235 xfree(remote_ipaddr);
1240 port_open_helper(Channel *c, char *rtype)
1244 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1245 int remote_port = get_peer_port(c->sock);
1247 direct = (strcmp(rtype, "direct-tcpip") == 0);
1249 snprintf(buf, sizeof buf,
1250 "%s: listening port %d for %.100s port %d, "
1251 "connect from %.200s port %d",
1252 rtype, c->listening_port, c->path, c->host_port,
1253 remote_ipaddr, remote_port);
1255 xfree(c->remote_name);
1256 c->remote_name = xstrdup(buf);
1259 packet_start(SSH2_MSG_CHANNEL_OPEN);
1260 packet_put_cstring(rtype);
1261 packet_put_int(c->self);
1262 packet_put_int(c->local_window_max);
1263 packet_put_int(c->local_maxpacket);
1265 /* target host, port */
1266 packet_put_cstring(c->path);
1267 packet_put_int(c->host_port);
1269 /* listen address, port */
1270 packet_put_cstring(c->path);
1271 packet_put_int(c->listening_port);
1273 /* originator host and port */
1274 packet_put_cstring(remote_ipaddr);
1275 packet_put_int((u_int)remote_port);
1278 packet_start(SSH_MSG_PORT_OPEN);
1279 packet_put_int(c->self);
1280 packet_put_cstring(c->path);
1281 packet_put_int(c->host_port);
1282 if (packet_get_protocol_flags() &
1283 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1284 packet_put_cstring(c->remote_name);
1287 xfree(remote_ipaddr);
1291 channel_set_reuseaddr(int fd)
1296 * Set socket options.
1297 * Allow local port reuse in TIME_WAIT.
1299 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1300 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1304 * This socket is listening for connections to a forwarded TCP/IP port.
1308 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1311 struct sockaddr addr;
1312 int newsock, nextstate;
1316 if (FD_ISSET(c->sock, readset)) {
1317 debug("Connection to port %d forwarding "
1318 "to %.100s port %d requested.",
1319 c->listening_port, c->path, c->host_port);
1321 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1322 nextstate = SSH_CHANNEL_OPENING;
1323 rtype = "forwarded-tcpip";
1325 if (c->host_port == 0) {
1326 nextstate = SSH_CHANNEL_DYNAMIC;
1327 rtype = "dynamic-tcpip";
1329 nextstate = SSH_CHANNEL_OPENING;
1330 rtype = "direct-tcpip";
1334 addrlen = sizeof(addr);
1335 newsock = accept(c->sock, &addr, &addrlen);
1337 error("accept: %.100s", strerror(errno));
1340 set_nodelay(newsock);
1341 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1342 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1343 nc->listening_port = c->listening_port;
1344 nc->host_port = c->host_port;
1345 strlcpy(nc->path, c->path, sizeof(nc->path));
1347 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1349 * do not call the channel_post handler until
1350 * this flag has been reset by a pre-handler.
1351 * otherwise the FD_ISSET calls might overflow
1355 port_open_helper(nc, rtype);
1361 * This is the authentication agent socket listening for connections from
1366 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1370 struct sockaddr addr;
1373 if (FD_ISSET(c->sock, readset)) {
1374 addrlen = sizeof(addr);
1375 newsock = accept(c->sock, &addr, &addrlen);
1377 error("accept from auth socket: %.100s", strerror(errno));
1380 nc = channel_new("accepted auth socket",
1381 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1382 c->local_window_max, c->local_maxpacket,
1383 0, "accepted auth socket", 1);
1385 packet_start(SSH2_MSG_CHANNEL_OPEN);
1386 packet_put_cstring("auth-agent@openssh.com");
1387 packet_put_int(nc->self);
1388 packet_put_int(c->local_window_max);
1389 packet_put_int(c->local_maxpacket);
1391 packet_start(SSH_SMSG_AGENT_OPEN);
1392 packet_put_int(nc->self);
1400 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1403 socklen_t sz = sizeof(err);
1405 if (FD_ISSET(c->sock, writeset)) {
1406 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1408 error("getsockopt SO_ERROR failed");
1411 debug("channel %d: connected", c->self);
1412 c->type = SSH_CHANNEL_OPEN;
1414 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1415 packet_put_int(c->remote_id);
1416 packet_put_int(c->self);
1417 packet_put_int(c->local_window);
1418 packet_put_int(c->local_maxpacket);
1420 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1421 packet_put_int(c->remote_id);
1422 packet_put_int(c->self);
1425 debug("channel %d: not connected: %s",
1426 c->self, strerror(err));
1428 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1429 packet_put_int(c->remote_id);
1430 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1431 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1432 packet_put_cstring(strerror(err));
1433 packet_put_cstring("");
1436 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1437 packet_put_int(c->remote_id);
1447 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1449 char buf[CHAN_RBUF];
1453 FD_ISSET(c->rfd, readset)) {
1455 len = read(c->rfd, buf, sizeof(buf));
1456 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1458 #ifndef PTY_ZEROREAD
1461 if ((!c->isatty && len <= 0) ||
1462 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1464 debug2("channel %d: read<=0 rfd %d len %d",
1465 c->self, c->rfd, len);
1466 if (c->type != SSH_CHANNEL_OPEN) {
1467 debug2("channel %d: not open", c->self);
1470 } else if (compat13) {
1471 buffer_clear(&c->output);
1472 c->type = SSH_CHANNEL_INPUT_DRAINING;
1473 debug2("channel %d: input draining.", c->self);
1475 chan_read_failed(c);
1479 if (c->input_filter != NULL) {
1480 if (c->input_filter(c, buf, len) == -1) {
1481 debug2("channel %d: filter stops", c->self);
1482 chan_read_failed(c);
1484 } else if (c->datagram) {
1485 buffer_put_string(&c->input, buf, len);
1487 buffer_append(&c->input, buf, len);
1495 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1498 u_char *data = NULL, *buf;
1502 /* Send buffered output data to the socket. */
1504 FD_ISSET(c->wfd, writeset) &&
1505 buffer_len(&c->output) > 0) {
1506 if (c->output_filter != NULL) {
1507 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1508 debug2("channel %d: filter stops", c->self);
1509 if (c->type != SSH_CHANNEL_OPEN)
1512 chan_write_failed(c);
1515 } else if (c->datagram) {
1516 buf = data = buffer_get_string(&c->output, &dlen);
1518 buf = data = buffer_ptr(&c->output);
1519 dlen = buffer_len(&c->output);
1523 /* ignore truncated writes, datagrams might get lost */
1524 c->local_consumed += dlen + 4;
1525 len = write(c->wfd, buf, dlen);
1527 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1530 if (c->type != SSH_CHANNEL_OPEN)
1533 chan_write_failed(c);
1539 /* XXX: Later AIX versions can't push as much data to tty */
1540 if (compat20 && c->wfd_isatty)
1541 dlen = MIN(dlen, 8*1024);
1544 len = write(c->wfd, buf, dlen);
1545 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1548 if (c->type != SSH_CHANNEL_OPEN) {
1549 debug2("channel %d: not open", c->self);
1552 } else if (compat13) {
1553 buffer_clear(&c->output);
1554 debug2("channel %d: input draining.", c->self);
1555 c->type = SSH_CHANNEL_INPUT_DRAINING;
1557 chan_write_failed(c);
1561 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1562 if (tcgetattr(c->wfd, &tio) == 0 &&
1563 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1565 * Simulate echo to reduce the impact of
1566 * traffic analysis. We need to match the
1567 * size of a SSH2_MSG_CHANNEL_DATA message
1568 * (4 byte channel id + buf)
1570 packet_send_ignore(4 + len);
1574 buffer_consume(&c->output, len);
1575 if (compat20 && len > 0) {
1576 c->local_consumed += len;
1583 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1585 char buf[CHAN_RBUF];
1588 /** XXX handle drain efd, too */
1590 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1591 FD_ISSET(c->efd, writeset) &&
1592 buffer_len(&c->extended) > 0) {
1593 len = write(c->efd, buffer_ptr(&c->extended),
1594 buffer_len(&c->extended));
1595 debug2("channel %d: written %d to efd %d",
1596 c->self, len, c->efd);
1597 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1600 debug2("channel %d: closing write-efd %d",
1602 channel_close_fd(&c->efd);
1604 buffer_consume(&c->extended, len);
1605 c->local_consumed += len;
1607 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1608 FD_ISSET(c->efd, readset)) {
1609 len = read(c->efd, buf, sizeof(buf));
1610 debug2("channel %d: read %d from efd %d",
1611 c->self, len, c->efd);
1612 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1615 debug2("channel %d: closing read-efd %d",
1617 channel_close_fd(&c->efd);
1619 buffer_append(&c->extended, buf, len);
1628 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1633 /* Monitor control fd to detect if the slave client exits */
1634 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1635 len = read(c->ctl_fd, buf, sizeof(buf));
1636 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1639 debug2("channel %d: ctl read<=0", c->self);
1640 if (c->type != SSH_CHANNEL_OPEN) {
1641 debug2("channel %d: not open", c->self);
1645 chan_read_failed(c);
1646 chan_write_failed(c);
1650 fatal("%s: unexpected data on ctl fd", __func__);
1656 channel_check_window(Channel *c)
1658 if (c->type == SSH_CHANNEL_OPEN &&
1659 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1660 c->local_window < c->local_window_max/2 &&
1661 c->local_consumed > 0) {
1663 /* adjust max window size if we are in a dynamic environment */
1664 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1665 addition = c->tcpwinsz - c->local_window_max;
1666 c->local_window_max += addition;
1668 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1669 packet_put_int(c->remote_id);
1670 packet_put_int(c->local_consumed + addition);
1672 debug2("channel %d: window %d sent adjust %d",
1673 c->self, c->local_window,
1675 c->local_window += c->local_consumed + addition;
1676 c->local_consumed = 0;
1682 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1686 channel_handle_rfd(c, readset, writeset);
1687 channel_handle_wfd(c, readset, writeset);
1690 channel_handle_efd(c, readset, writeset);
1691 channel_handle_ctl(c, readset, writeset);
1692 channel_check_window(c);
1697 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1701 /* Send buffered output data to the socket. */
1702 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1703 len = write(c->sock, buffer_ptr(&c->output),
1704 buffer_len(&c->output));
1706 buffer_clear(&c->output);
1708 buffer_consume(&c->output, len);
1713 channel_handler_init_20(void)
1715 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1716 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1717 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1718 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1719 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1720 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1721 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1722 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1724 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1725 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1726 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1727 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1728 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1729 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1730 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1734 channel_handler_init_13(void)
1736 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1737 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1738 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1739 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1740 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1741 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1742 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1743 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1744 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1746 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1747 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1748 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1749 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1750 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1751 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1752 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1756 channel_handler_init_15(void)
1758 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1759 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1760 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1761 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1762 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1763 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1764 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1766 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1767 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1768 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1769 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1770 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1771 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1775 channel_handler_init(void)
1779 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1780 channel_pre[i] = NULL;
1781 channel_post[i] = NULL;
1784 channel_handler_init_20();
1786 channel_handler_init_13();
1788 channel_handler_init_15();
1791 /* gc dead channels */
1793 channel_garbage_collect(Channel *c)
1797 if (c->detach_user != NULL) {
1798 if (!chan_is_dead(c, c->detach_close))
1800 debug2("channel %d: gc: notify user", c->self);
1801 c->detach_user(c->self, NULL);
1802 /* if we still have a callback */
1803 if (c->detach_user != NULL)
1805 debug2("channel %d: gc: user detached", c->self);
1807 if (!chan_is_dead(c, 1))
1809 debug2("channel %d: garbage collecting", c->self);
1814 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1816 static int did_init = 0;
1821 channel_handler_init();
1824 for (i = 0; i < channels_alloc; i++) {
1828 if (ftab[c->type] != NULL)
1829 (*ftab[c->type])(c, readset, writeset);
1830 channel_garbage_collect(c);
1835 * Allocate/update select bitmasks and add any bits relevant to channels in
1839 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1840 u_int *nallocp, int rekeying)
1842 u_int n, sz, nfdset;
1844 n = MAX(*maxfdp, channel_max_fd);
1846 nfdset = howmany(n+1, NFDBITS);
1847 /* Explicitly test here, because xrealloc isn't always called */
1848 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1849 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1850 sz = nfdset * sizeof(fd_mask);
1852 /* perhaps check sz < nalloc/2 and shrink? */
1853 if (*readsetp == NULL || sz > *nallocp) {
1854 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1855 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1859 memset(*readsetp, 0, sz);
1860 memset(*writesetp, 0, sz);
1863 channel_handler(channel_pre, *readsetp, *writesetp);
1867 * After select, perform any appropriate operations for channels which have
1871 channel_after_select(fd_set *readset, fd_set *writeset)
1873 channel_handler(channel_post, readset, writeset);
1877 /* If there is data to send to the connection, enqueue some of it now. */
1879 channel_output_poll(void)
1884 for (i = 0; i < channels_alloc; i++) {
1890 * We are only interested in channels that can have buffered
1894 if (c->type != SSH_CHANNEL_OPEN &&
1895 c->type != SSH_CHANNEL_INPUT_DRAINING)
1898 if (c->type != SSH_CHANNEL_OPEN)
1902 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1903 /* XXX is this true? */
1904 debug3("channel %d: will not send data after close", c->self);
1908 /* Get the amount of buffered data for this channel. */
1909 if ((c->istate == CHAN_INPUT_OPEN ||
1910 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1911 (len = buffer_len(&c->input)) > 0) {
1917 data = buffer_get_string(&c->input,
1919 packet_start(SSH2_MSG_CHANNEL_DATA);
1920 packet_put_int(c->remote_id);
1921 packet_put_string(data, dlen);
1923 c->remote_window -= dlen + 4;
1929 * Send some data for the other side over the secure
1933 if (len > c->remote_window)
1934 len = c->remote_window;
1935 if (len > c->remote_maxpacket)
1936 len = c->remote_maxpacket;
1938 if (packet_is_interactive()) {
1942 /* Keep the packets at reasonable size. */
1943 if (len > packet_get_maxsize()/2)
1944 len = packet_get_maxsize()/2;
1948 packet_start(compat20 ?
1949 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1950 packet_put_int(c->remote_id);
1951 packet_put_string(buffer_ptr(&c->input), len);
1953 buffer_consume(&c->input, len);
1954 c->remote_window -= len;
1956 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1958 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1960 * input-buffer is empty and read-socket shutdown:
1961 * tell peer, that we will not send more data: send IEOF.
1962 * hack for extended data: delay EOF if EFD still in use.
1964 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1965 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1966 c->self, c->efd, buffer_len(&c->extended));
1970 /* Send extended data, i.e. stderr */
1972 !(c->flags & CHAN_EOF_SENT) &&
1973 c->remote_window > 0 &&
1974 (len = buffer_len(&c->extended)) > 0 &&
1975 c->extended_usage == CHAN_EXTENDED_READ) {
1976 debug2("channel %d: rwin %u elen %u euse %d",
1977 c->self, c->remote_window, buffer_len(&c->extended),
1979 if (len > c->remote_window)
1980 len = c->remote_window;
1981 if (len > c->remote_maxpacket)
1982 len = c->remote_maxpacket;
1983 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1984 packet_put_int(c->remote_id);
1985 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1986 packet_put_string(buffer_ptr(&c->extended), len);
1988 buffer_consume(&c->extended, len);
1989 c->remote_window -= len;
1990 debug2("channel %d: sent ext data %d", c->self, len);
1996 /* -- protocol input */
2000 channel_input_data(int type, u_int32_t seq, void *ctxt)
2007 /* Get the channel number and verify it. */
2008 id = packet_get_int();
2009 c = channel_lookup(id);
2011 packet_disconnect("Received data for nonexistent channel %d.", id);
2013 /* Ignore any data for non-open channels (might happen on close) */
2014 if (c->type != SSH_CHANNEL_OPEN &&
2015 c->type != SSH_CHANNEL_X11_OPEN)
2019 data = packet_get_string(&data_len);
2022 * Ignore data for protocol > 1.3 if output end is no longer open.
2023 * For protocol 2 the sending side is reducing its window as it sends
2024 * data, so we must 'fake' consumption of the data in order to ensure
2025 * that window updates are sent back. Otherwise the connection might
2028 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2030 c->local_window -= data_len;
2031 c->local_consumed += data_len;
2038 if (data_len > c->local_maxpacket) {
2039 logit("channel %d: rcvd big packet %d, maxpack %d",
2040 c->self, data_len, c->local_maxpacket);
2042 if (data_len > c->local_window) {
2043 logit("channel %d: rcvd too much data %d, win %d",
2044 c->self, data_len, c->local_window);
2048 c->local_window -= data_len;
2052 buffer_put_string(&c->output, data, data_len);
2054 buffer_append(&c->output, data, data_len);
2060 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2064 u_int data_len, tcode;
2067 /* Get the channel number and verify it. */
2068 id = packet_get_int();
2069 c = channel_lookup(id);
2072 packet_disconnect("Received extended_data for bad channel %d.", id);
2073 if (c->type != SSH_CHANNEL_OPEN) {
2074 logit("channel %d: ext data for non open", id);
2077 if (c->flags & CHAN_EOF_RCVD) {
2078 if (datafellows & SSH_BUG_EXTEOF)
2079 debug("channel %d: accepting ext data after eof", id);
2081 packet_disconnect("Received extended_data after EOF "
2082 "on channel %d.", id);
2084 tcode = packet_get_int();
2086 c->extended_usage != CHAN_EXTENDED_WRITE ||
2087 tcode != SSH2_EXTENDED_DATA_STDERR) {
2088 logit("channel %d: bad ext data", c->self);
2091 data = packet_get_string(&data_len);
2093 if (data_len > c->local_window) {
2094 logit("channel %d: rcvd too much extended_data %d, win %d",
2095 c->self, data_len, c->local_window);
2099 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2100 c->local_window -= data_len;
2101 buffer_append(&c->extended, data, data_len);
2107 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2112 id = packet_get_int();
2114 c = channel_lookup(id);
2116 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2119 /* XXX force input close */
2120 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2121 debug("channel %d: FORCE input drain", c->self);
2122 c->istate = CHAN_INPUT_WAIT_DRAIN;
2123 if (buffer_len(&c->input) == 0)
2131 channel_input_close(int type, u_int32_t seq, void *ctxt)
2136 id = packet_get_int();
2138 c = channel_lookup(id);
2140 packet_disconnect("Received close for nonexistent channel %d.", id);
2143 * Send a confirmation that we have closed the channel and no more
2144 * data is coming for it.
2146 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2147 packet_put_int(c->remote_id);
2151 * If the channel is in closed state, we have sent a close request,
2152 * and the other side will eventually respond with a confirmation.
2153 * Thus, we cannot free the channel here, because then there would be
2154 * no-one to receive the confirmation. The channel gets freed when
2155 * the confirmation arrives.
2157 if (c->type != SSH_CHANNEL_CLOSED) {
2159 * Not a closed channel - mark it as draining, which will
2160 * cause it to be freed later.
2162 buffer_clear(&c->input);
2163 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2167 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2170 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2172 int id = packet_get_int();
2173 Channel *c = channel_lookup(id);
2177 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2178 chan_rcvd_oclose(c);
2183 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2185 int id = packet_get_int();
2186 Channel *c = channel_lookup(id);
2190 packet_disconnect("Received close confirmation for "
2191 "out-of-range channel %d.", id);
2192 if (c->type != SSH_CHANNEL_CLOSED)
2193 packet_disconnect("Received close confirmation for "
2194 "non-closed channel %d (type %d).", id, c->type);
2200 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2205 id = packet_get_int();
2206 c = channel_lookup(id);
2208 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2209 packet_disconnect("Received open confirmation for "
2210 "non-opening channel %d.", id);
2211 remote_id = packet_get_int();
2212 /* Record the remote channel number and mark that the channel is now open. */
2213 c->remote_id = remote_id;
2214 c->type = SSH_CHANNEL_OPEN;
2217 c->remote_window = packet_get_int();
2218 c->remote_maxpacket = packet_get_int();
2220 debug2("callback start");
2221 c->confirm(c->self, c->confirm_ctx);
2222 debug2("callback done");
2224 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2225 c->remote_window, c->remote_maxpacket);
2231 reason2txt(int reason)
2234 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2235 return "administratively prohibited";
2236 case SSH2_OPEN_CONNECT_FAILED:
2237 return "connect failed";
2238 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2239 return "unknown channel type";
2240 case SSH2_OPEN_RESOURCE_SHORTAGE:
2241 return "resource shortage";
2243 return "unknown reason";
2248 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2251 char *msg = NULL, *lang = NULL;
2254 id = packet_get_int();
2255 c = channel_lookup(id);
2257 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2258 packet_disconnect("Received open failure for "
2259 "non-opening channel %d.", id);
2261 reason = packet_get_int();
2262 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2263 msg = packet_get_string(NULL);
2264 lang = packet_get_string(NULL);
2266 logit("channel %d: open failed: %s%s%s", id,
2267 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2274 /* Free the channel. This will also close the socket. */
2280 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2289 /* Get the channel number and verify it. */
2290 id = packet_get_int();
2291 c = channel_lookup(id);
2294 logit("Received window adjust for non-open channel %d.", id);
2297 adjust = packet_get_int();
2299 debug2("channel %d: rcvd adjust %u", id, adjust);
2300 c->remote_window += adjust;
2305 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2309 char *host, *originator_string;
2310 int remote_id, sock = -1;
2312 remote_id = packet_get_int();
2313 host = packet_get_string(NULL);
2314 host_port = packet_get_int();
2316 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2317 originator_string = packet_get_string(NULL);
2319 originator_string = xstrdup("unknown (remote did not supply name)");
2322 sock = channel_connect_to(host, host_port);
2324 c = channel_new("connected socket",
2325 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2326 originator_string, 1);
2327 c->remote_id = remote_id;
2329 xfree(originator_string);
2331 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2332 packet_put_int(remote_id);
2339 /* -- tcp forwarding */
2342 channel_set_af(int af)
2348 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2349 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2350 int hpn_disabled, int hpn_buffer_size)
2353 int sock, r, success = 0, wildcard = 0, is_client;
2354 struct addrinfo hints, *ai, *aitop;
2355 const char *host, *addr;
2356 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2358 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2359 listen_addr : host_to_connect;
2360 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2363 error("No forward host name.");
2366 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2367 error("Forward host name too long.");
2372 * Determine whether or not a port forward listens to loopback,
2373 * specified address or wildcard. On the client, a specified bind
2374 * address will always override gateway_ports. On the server, a
2375 * gateway_ports of 1 (``yes'') will override the client's
2376 * specification and force a wildcard bind, whereas a value of 2
2377 * (``clientspecified'') will bind to whatever address the client
2380 * Special-case listen_addrs are:
2382 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2383 * "" (empty string), "*" -> wildcard v4/v6
2384 * "localhost" -> loopback v4/v6
2387 if (listen_addr == NULL) {
2388 /* No address specified: default to gateway_ports setting */
2391 } else if (gateway_ports || is_client) {
2392 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2393 strcmp(listen_addr, "0.0.0.0") == 0) ||
2394 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2395 (!is_client && gateway_ports == 1))
2397 else if (strcmp(listen_addr, "localhost") != 0)
2401 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2402 type, wildcard, (addr == NULL) ? "NULL" : addr);
2405 * getaddrinfo returns a loopback address if the hostname is
2406 * set to NULL and hints.ai_flags is not AI_PASSIVE
2408 memset(&hints, 0, sizeof(hints));
2409 hints.ai_family = IPv4or6;
2410 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2411 hints.ai_socktype = SOCK_STREAM;
2412 snprintf(strport, sizeof strport, "%d", listen_port);
2413 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2415 /* This really shouldn't happen */
2416 packet_disconnect("getaddrinfo: fatal error: %s",
2419 error("channel_setup_fwd_listener: "
2420 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2425 for (ai = aitop; ai; ai = ai->ai_next) {
2426 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2428 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2429 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2430 error("channel_setup_fwd_listener: getnameinfo failed");
2433 /* Create a port to listen for the host. */
2434 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2436 /* this is no error since kernel may not support ipv6 */
2437 verbose("socket: %.100s", strerror(errno));
2441 channel_set_reuseaddr(sock);
2443 debug("Local forwarding listening on %s port %s.", ntop, strport);
2445 /* Bind the socket to the address. */
2446 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2447 /* address can be in use ipv6 address is already bound */
2449 error("bind: %.100s", strerror(errno));
2451 verbose("bind: %.100s", strerror(errno));
2456 /* Start listening for connections on the socket. */
2457 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2458 error("listen: %.100s", strerror(errno));
2462 /* Allocate a channel number for the socket. */
2463 /* explicitly test for hpn disabled option. if true use smaller window size */
2465 c = channel_new("port listener", type, sock, sock, -1,
2466 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2467 0, "port listener", 1);
2469 c = channel_new("port listener", type, sock, sock, -1,
2470 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2471 0, "port listener", 1);
2472 strlcpy(c->path, host, sizeof(c->path));
2473 c->host_port = port_to_connect;
2474 c->listening_port = listen_port;
2478 error("channel_setup_fwd_listener: cannot listen to port: %d",
2480 freeaddrinfo(aitop);
2485 channel_cancel_rport_listener(const char *host, u_short port)
2490 for (i = 0; i < channels_alloc; i++) {
2491 Channel *c = channels[i];
2493 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2494 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2495 c->listening_port == port) {
2496 debug2("%s: close channel %d", __func__, i);
2505 /* protocol local port fwd, used by ssh (and sshd in v1) */
2507 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2508 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2509 int hpn_disabled, int hpn_buffer_size)
2511 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2512 listen_host, listen_port, host_to_connect, port_to_connect,
2513 gateway_ports, hpn_disabled, hpn_buffer_size);
2516 /* protocol v2 remote port fwd, used by sshd */
2518 channel_setup_remote_fwd_listener(const char *listen_address,
2519 u_short listen_port, int gateway_ports, int hpn_disabled, int hpn_buffer_size)
2521 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2522 listen_address, listen_port, NULL, 0, gateway_ports,
2523 hpn_disabled, hpn_buffer_size);
2527 * Initiate forwarding of connections to port "port" on remote host through
2528 * the secure channel to host:port from local side.
2532 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2533 const char *host_to_connect, u_short port_to_connect)
2535 int type, success = 0;
2537 /* Record locally that connection to this host/port is permitted. */
2538 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2539 fatal("channel_request_remote_forwarding: too many forwards");
2541 /* Send the forward request to the remote side. */
2543 const char *address_to_bind;
2544 if (listen_host == NULL)
2545 address_to_bind = "localhost";
2546 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2547 address_to_bind = "";
2549 address_to_bind = listen_host;
2551 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2552 packet_put_cstring("tcpip-forward");
2553 packet_put_char(1); /* boolean: want reply */
2554 packet_put_cstring(address_to_bind);
2555 packet_put_int(listen_port);
2557 packet_write_wait();
2558 /* Assume that server accepts the request */
2561 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2562 packet_put_int(listen_port);
2563 packet_put_cstring(host_to_connect);
2564 packet_put_int(port_to_connect);
2566 packet_write_wait();
2568 /* Wait for response from the remote side. */
2569 type = packet_read();
2571 case SSH_SMSG_SUCCESS:
2574 case SSH_SMSG_FAILURE:
2577 /* Unknown packet */
2578 packet_disconnect("Protocol error for port forward request:"
2579 "received packet type %d.", type);
2583 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2584 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2585 permitted_opens[num_permitted_opens].listen_port = listen_port;
2586 num_permitted_opens++;
2588 return (success ? 0 : -1);
2592 * Request cancellation of remote forwarding of connection host:port from
2596 channel_request_rforward_cancel(const char *host, u_short port)
2603 for (i = 0; i < num_permitted_opens; i++) {
2604 if (permitted_opens[i].host_to_connect != NULL &&
2605 permitted_opens[i].listen_port == port)
2608 if (i >= num_permitted_opens) {
2609 debug("%s: requested forward not found", __func__);
2612 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2613 packet_put_cstring("cancel-tcpip-forward");
2615 packet_put_cstring(host == NULL ? "" : host);
2616 packet_put_int(port);
2619 permitted_opens[i].listen_port = 0;
2620 permitted_opens[i].port_to_connect = 0;
2621 xfree(permitted_opens[i].host_to_connect);
2622 permitted_opens[i].host_to_connect = NULL;
2626 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2627 * listening for the port, and sends back a success reply (or disconnect
2628 * message if there was an error).
2631 channel_input_port_forward_request(int is_root, int gateway_ports,
2632 int hpn_disabled, int hpn_buffer_size)
2634 u_short port, host_port;
2638 /* Get arguments from the packet. */
2639 port = packet_get_int();
2640 hostname = packet_get_string(NULL);
2641 host_port = packet_get_int();
2645 * Check that an unprivileged user is not trying to forward a
2648 if (port < IPPORT_RESERVED && !is_root)
2650 "Requested forwarding of port %d but user is not root.",
2653 packet_disconnect("Dynamic forwarding denied.");
2656 /* Initiate forwarding */
2657 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2658 host_port, gateway_ports, hpn_disabled, hpn_buffer_size);
2660 /* Free the argument string. */
2663 return (success ? 0 : -1);
2667 * Permits opening to any host/port if permitted_opens[] is empty. This is
2668 * usually called by the server, because the user could connect to any port
2669 * anyway, and the server has no way to know but to trust the client anyway.
2672 channel_permit_all_opens(void)
2674 if (num_permitted_opens == 0)
2675 all_opens_permitted = 1;
2679 channel_add_permitted_opens(char *host, int port)
2681 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2682 fatal("channel_add_permitted_opens: too many forwards");
2683 debug("allow port forwarding to host %s port %d", host, port);
2685 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2686 permitted_opens[num_permitted_opens].port_to_connect = port;
2687 num_permitted_opens++;
2689 all_opens_permitted = 0;
2693 channel_add_adm_permitted_opens(char *host, int port)
2695 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2696 fatal("channel_add_adm_permitted_opens: too many forwards");
2697 debug("config allows port forwarding to host %s port %d", host, port);
2699 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2701 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2702 return ++num_adm_permitted_opens;
2706 channel_clear_permitted_opens(void)
2710 for (i = 0; i < num_permitted_opens; i++)
2711 if (permitted_opens[i].host_to_connect != NULL)
2712 xfree(permitted_opens[i].host_to_connect);
2713 num_permitted_opens = 0;
2717 channel_clear_adm_permitted_opens(void)
2721 for (i = 0; i < num_adm_permitted_opens; i++)
2722 if (permitted_adm_opens[i].host_to_connect != NULL)
2723 xfree(permitted_adm_opens[i].host_to_connect);
2724 num_adm_permitted_opens = 0;
2727 /* return socket to remote host, port */
2729 connect_to(const char *host, u_short port)
2731 struct addrinfo hints, *ai, *aitop;
2732 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2736 memset(&hints, 0, sizeof(hints));
2737 hints.ai_family = IPv4or6;
2738 hints.ai_socktype = SOCK_STREAM;
2739 snprintf(strport, sizeof strport, "%d", port);
2740 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2741 error("connect_to %.100s: unknown host (%s)", host,
2742 gai_strerror(gaierr));
2745 for (ai = aitop; ai; ai = ai->ai_next) {
2746 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2748 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2749 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2750 error("connect_to: getnameinfo failed");
2753 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2755 if (ai->ai_next == NULL)
2756 error("socket: %.100s", strerror(errno));
2758 verbose("socket: %.100s", strerror(errno));
2761 if (set_nonblock(sock) == -1)
2762 fatal("%s: set_nonblock(%d)", __func__, sock);
2763 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2764 errno != EINPROGRESS) {
2765 error("connect_to %.100s port %s: %.100s", ntop, strport,
2768 continue; /* fail -- try next */
2770 break; /* success */
2773 freeaddrinfo(aitop);
2775 error("connect_to %.100s port %d: failed.", host, port);
2784 channel_connect_by_listen_address(u_short listen_port)
2788 for (i = 0; i < num_permitted_opens; i++)
2789 if (permitted_opens[i].host_to_connect != NULL &&
2790 permitted_opens[i].listen_port == listen_port)
2792 permitted_opens[i].host_to_connect,
2793 permitted_opens[i].port_to_connect);
2794 error("WARNING: Server requests forwarding for unknown listen_port %d",
2799 /* Check if connecting to that port is permitted and connect. */
2801 channel_connect_to(const char *host, u_short port)
2803 int i, permit, permit_adm = 1;
2805 permit = all_opens_permitted;
2807 for (i = 0; i < num_permitted_opens; i++)
2808 if (permitted_opens[i].host_to_connect != NULL &&
2809 permitted_opens[i].port_to_connect == port &&
2810 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2814 if (num_adm_permitted_opens > 0) {
2816 for (i = 0; i < num_adm_permitted_opens; i++)
2817 if (permitted_adm_opens[i].host_to_connect != NULL &&
2818 permitted_adm_opens[i].port_to_connect == port &&
2819 strcmp(permitted_adm_opens[i].host_to_connect, host)
2824 if (!permit || !permit_adm) {
2825 logit("Received request to connect to host %.100s port %d, "
2826 "but the request was denied.", host, port);
2829 return connect_to(host, port);
2833 channel_send_window_changes(void)
2838 for (i = 0; i < channels_alloc; i++) {
2839 if (channels[i] == NULL || !channels[i]->client_tty ||
2840 channels[i]->type != SSH_CHANNEL_OPEN)
2842 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2844 channel_request_start(i, "window-change", 0);
2845 packet_put_int((u_int)ws.ws_col);
2846 packet_put_int((u_int)ws.ws_row);
2847 packet_put_int((u_int)ws.ws_xpixel);
2848 packet_put_int((u_int)ws.ws_ypixel);
2853 /* -- X11 forwarding */
2856 * Creates an internet domain socket for listening for X11 connections.
2857 * Returns 0 and a suitable display number for the DISPLAY variable
2858 * stored in display_numberp , or -1 if an error occurs.
2861 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2862 int single_connection, u_int *display_numberp, int **chanids,
2863 int hpn_disabled, int hpn_buffer_size)
2866 int display_number, sock;
2868 struct addrinfo hints, *ai, *aitop;
2869 char strport[NI_MAXSERV];
2870 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2872 if (chanids == NULL)
2875 for (display_number = x11_display_offset;
2876 display_number < MAX_DISPLAYS;
2878 port = 6000 + display_number;
2879 memset(&hints, 0, sizeof(hints));
2880 hints.ai_family = IPv4or6;
2881 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2882 hints.ai_socktype = SOCK_STREAM;
2883 snprintf(strport, sizeof strport, "%d", port);
2884 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2885 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2888 for (ai = aitop; ai; ai = ai->ai_next) {
2889 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2891 sock = socket(ai->ai_family, ai->ai_socktype,
2894 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2895 error("socket: %.100s", strerror(errno));
2896 freeaddrinfo(aitop);
2899 debug("x11_create_display_inet: Socket family %d not supported",
2905 if (ai->ai_family == AF_INET6) {
2907 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2908 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2911 channel_set_reuseaddr(sock);
2912 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2913 debug2("bind port %d: %.100s", port, strerror(errno));
2919 for (n = 0; n < num_socks; n++) {
2925 socks[num_socks++] = sock;
2926 #ifndef DONT_TRY_OTHER_AF
2927 if (num_socks == NUM_SOCKS)
2930 if (x11_use_localhost) {
2931 if (num_socks == NUM_SOCKS)
2938 freeaddrinfo(aitop);
2942 if (display_number >= MAX_DISPLAYS) {
2943 error("Failed to allocate internet-domain X11 display socket.");
2946 /* Start listening for connections on the socket. */
2947 for (n = 0; n < num_socks; n++) {
2949 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2950 error("listen: %.100s", strerror(errno));
2956 /* Allocate a channel for each socket. */
2957 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2958 for (n = 0; n < num_socks; n++) {
2961 nc = channel_new("x11 listener",
2962 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2963 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2964 0, "X11 inet listener", 1);
2966 nc = channel_new("x11 listener",
2967 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2968 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
2969 0, "X11 inet listener", 1);
2970 nc->single_connection = single_connection;
2971 (*chanids)[n] = nc->self;
2975 /* Return the display number for the DISPLAY environment variable. */
2976 *display_numberp = display_number;
2981 connect_local_xsocket(u_int dnr)
2984 struct sockaddr_un addr;
2986 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2988 error("socket: %.100s", strerror(errno));
2989 memset(&addr, 0, sizeof(addr));
2990 addr.sun_family = AF_UNIX;
2991 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2992 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
2995 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3000 x11_connect_display(void)
3002 u_int display_number;
3003 const char *display;
3004 char buf[1024], *cp;
3005 struct addrinfo hints, *ai, *aitop;
3006 char strport[NI_MAXSERV];
3007 int gaierr, sock = 0;
3009 /* Try to open a socket for the local X server. */
3010 display = getenv("DISPLAY");
3012 error("DISPLAY not set.");
3016 * Now we decode the value of the DISPLAY variable and make a
3017 * connection to the real X server.
3021 * Check if it is a unix domain socket. Unix domain displays are in
3022 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3024 if (strncmp(display, "unix:", 5) == 0 ||
3025 display[0] == ':') {
3026 /* Connect to the unix domain socket. */
3027 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3028 error("Could not parse display number from DISPLAY: %.100s",
3032 /* Create a socket. */
3033 sock = connect_local_xsocket(display_number);
3037 /* OK, we now have a connection to the display. */
3041 * Connect to an inet socket. The DISPLAY value is supposedly
3042 * hostname:d[.s], where hostname may also be numeric IP address.
3044 strlcpy(buf, display, sizeof(buf));
3045 cp = strchr(buf, ':');
3047 error("Could not find ':' in DISPLAY: %.100s", display);
3051 /* buf now contains the host name. But first we parse the display number. */
3052 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3053 error("Could not parse display number from DISPLAY: %.100s",
3058 /* Look up the host address */
3059 memset(&hints, 0, sizeof(hints));
3060 hints.ai_family = IPv4or6;
3061 hints.ai_socktype = SOCK_STREAM;
3062 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3063 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3064 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
3067 for (ai = aitop; ai; ai = ai->ai_next) {
3068 /* Create a socket. */
3069 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3071 debug2("socket: %.100s", strerror(errno));
3074 /* Connect it to the display. */
3075 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3076 debug2("connect %.100s port %u: %.100s", buf,
3077 6000 + display_number, strerror(errno));
3084 freeaddrinfo(aitop);
3086 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3095 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3096 * the remote channel number. We should do whatever we want, and respond
3097 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3102 x11_input_open(int type, u_int32_t seq, void *ctxt)
3105 int remote_id, sock = 0;
3108 debug("Received X11 open request.");
3110 remote_id = packet_get_int();
3112 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3113 remote_host = packet_get_string(NULL);
3115 remote_host = xstrdup("unknown (remote did not supply name)");
3119 /* Obtain a connection to the real X display. */
3120 sock = x11_connect_display();
3122 /* Allocate a channel for this connection. */
3123 c = channel_new("connected x11 socket",
3124 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3126 c->remote_id = remote_id;
3131 /* Send refusal to the remote host. */
3132 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3133 packet_put_int(remote_id);
3135 /* Send a confirmation to the remote host. */
3136 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3137 packet_put_int(remote_id);
3138 packet_put_int(c->self);
3143 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3146 deny_input_open(int type, u_int32_t seq, void *ctxt)
3148 int rchan = packet_get_int();
3151 case SSH_SMSG_AGENT_OPEN:
3152 error("Warning: ssh server tried agent forwarding.");
3154 case SSH_SMSG_X11_OPEN:
3155 error("Warning: ssh server tried X11 forwarding.");
3158 error("deny_input_open: type %d", type);
3161 error("Warning: this is probably a break-in attempt by a malicious server.");
3162 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3163 packet_put_int(rchan);
3168 * Requests forwarding of X11 connections, generates fake authentication
3169 * data, and enables authentication spoofing.
3170 * This should be called in the client only.
3173 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3174 const char *proto, const char *data)
3176 u_int data_len = (u_int) strlen(data) / 2;
3183 if (x11_saved_display == NULL)
3184 x11_saved_display = xstrdup(disp);
3185 else if (strcmp(disp, x11_saved_display) != 0) {
3186 error("x11_request_forwarding_with_spoofing: different "
3187 "$DISPLAY already forwarded");
3191 cp = strchr(disp, ':');
3193 cp = strchr(cp, '.');
3195 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3199 if (x11_saved_proto == NULL) {
3200 /* Save protocol name. */
3201 x11_saved_proto = xstrdup(proto);
3203 * Extract real authentication data and generate fake data
3204 * of the same length.
3206 x11_saved_data = xmalloc(data_len);
3207 x11_fake_data = xmalloc(data_len);
3208 for (i = 0; i < data_len; i++) {
3209 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3210 fatal("x11_request_forwarding: bad "
3211 "authentication data: %.100s", data);
3214 x11_saved_data[i] = value;
3215 x11_fake_data[i] = rnd & 0xff;
3218 x11_saved_data_len = data_len;
3219 x11_fake_data_len = data_len;
3222 /* Convert the fake data into hex. */
3223 new_data = tohex(x11_fake_data, data_len);
3225 /* Send the request packet. */
3227 channel_request_start(client_session_id, "x11-req", 0);
3228 packet_put_char(0); /* XXX bool single connection */
3230 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3232 packet_put_cstring(proto);
3233 packet_put_cstring(new_data);
3234 packet_put_int(screen_number);
3236 packet_write_wait();
3241 /* -- agent forwarding */
3243 /* Sends a message to the server to request authentication fd forwarding. */
3246 auth_request_forwarding(void)
3248 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3250 packet_write_wait();