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"
83 * Pointer to an array containing all allocated channels. The array is
84 * dynamically extended as needed.
86 static Channel **channels = NULL;
89 * Size of the channel array. All slots of the array must always be
90 * initialized (at least the type field); unused slots set to NULL
92 static u_int channels_alloc = 0;
95 * Maximum file descriptor value used in any of the channels. This is
96 * updated in channel_new.
98 static int channel_max_fd = 0;
101 /* -- tcp forwarding */
104 * Data structure for storing which hosts are permitted for forward requests.
105 * The local sides of any remote forwards are stored in this array to prevent
106 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
107 * network (which might be behind a firewall).
110 char *host_to_connect; /* Connect to 'host'. */
111 u_short port_to_connect; /* Connect to 'port'. */
112 u_short listen_port; /* Remote side should listen port number. */
115 /* List of all permitted host/port pairs to connect by the user. */
116 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
118 /* List of all permitted host/port pairs to connect by the admin. */
119 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
121 /* Number of permitted host/port pairs in the array permitted by the user. */
122 static int num_permitted_opens = 0;
124 /* Number of permitted host/port pair in the array permitted by the admin. */
125 static int num_adm_permitted_opens = 0;
128 * If this is true, all opens are permitted. This is the case on the server
129 * on which we have to trust the client anyway, and the user could do
130 * anything after logging in anyway.
132 static int all_opens_permitted = 0;
135 /* -- X11 forwarding */
137 /* Maximum number of fake X11 displays to try. */
138 #define MAX_DISPLAYS 1000
140 /* Saved X11 local (client) display. */
141 static char *x11_saved_display = NULL;
143 /* Saved X11 authentication protocol name. */
144 static char *x11_saved_proto = NULL;
146 /* Saved X11 authentication data. This is the real data. */
147 static char *x11_saved_data = NULL;
148 static u_int x11_saved_data_len = 0;
151 * Fake X11 authentication data. This is what the server will be sending us;
152 * we should replace any occurrences of this by the real data.
154 static u_char *x11_fake_data = NULL;
155 static u_int x11_fake_data_len;
158 /* -- agent forwarding */
162 /* AF_UNSPEC or AF_INET or AF_INET6 */
163 static int IPv4or6 = AF_UNSPEC;
166 static void port_open_helper(Channel *c, char *rtype);
168 /* -- channel core */
171 channel_by_id(int id)
175 if (id < 0 || (u_int)id >= channels_alloc) {
176 logit("channel_by_id: %d: bad id", id);
181 logit("channel_by_id: %d: bad id: channel free", id);
188 * Returns the channel if it is allowed to receive protocol messages.
189 * Private channels, like listening sockets, may not receive messages.
192 channel_lookup(int id)
196 if ((c = channel_by_id(id)) == NULL)
200 case SSH_CHANNEL_X11_OPEN:
201 case SSH_CHANNEL_LARVAL:
202 case SSH_CHANNEL_CONNECTING:
203 case SSH_CHANNEL_DYNAMIC:
204 case SSH_CHANNEL_OPENING:
205 case SSH_CHANNEL_OPEN:
206 case SSH_CHANNEL_INPUT_DRAINING:
207 case SSH_CHANNEL_OUTPUT_DRAINING:
210 logit("Non-public channel %d, type %d.", id, c->type);
215 * Register filedescriptors for a channel, used when allocating a channel or
216 * when the channel consumer/producer is ready, e.g. shell exec'd
219 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
220 int extusage, int nonblock)
222 /* Update the maximum file descriptor value. */
223 channel_max_fd = MAX(channel_max_fd, rfd);
224 channel_max_fd = MAX(channel_max_fd, wfd);
225 channel_max_fd = MAX(channel_max_fd, efd);
227 /* XXX set close-on-exec -markus */
231 c->sock = (rfd == wfd) ? rfd : -1;
232 c->ctl_fd = -1; /* XXX: set elsewhere */
234 c->extended_usage = extusage;
236 /* XXX ugly hack: nonblock is only set by the server */
237 if (nonblock && isatty(c->rfd)) {
238 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
240 if (!isatty(c->wfd)) {
241 error("channel %d: wfd %d is not a tty?",
247 c->wfd_isatty = isatty(c->wfd);
249 /* enable nonblocking mode */
261 * Allocate a new channel object and set its type and socket. This will cause
262 * remote_name to be freed.
265 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
266 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
272 /* Do initial allocation if this is the first call. */
273 if (channels_alloc == 0) {
275 channels = xcalloc(channels_alloc, sizeof(Channel *));
276 for (i = 0; i < channels_alloc; i++)
279 /* Try to find a free slot where to put the new channel. */
280 for (found = -1, i = 0; i < channels_alloc; i++)
281 if (channels[i] == NULL) {
282 /* Found a free slot. */
287 /* There are no free slots. Take last+1 slot and expand the array. */
288 found = channels_alloc;
289 if (channels_alloc > 10000)
290 fatal("channel_new: internal error: channels_alloc %d "
291 "too big.", channels_alloc);
292 channels = xrealloc(channels, channels_alloc + 10,
294 channels_alloc += 10;
295 debug2("channel: expanding %d", channels_alloc);
296 for (i = found; i < channels_alloc; i++)
299 /* Initialize and return new channel. */
300 c = channels[found] = xcalloc(1, sizeof(Channel));
301 buffer_init(&c->input);
302 buffer_init(&c->output);
303 buffer_init(&c->extended);
304 c->ostate = CHAN_OUTPUT_OPEN;
305 c->istate = CHAN_INPUT_OPEN;
307 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
311 c->local_window = window;
312 c->local_window_max = window;
313 c->local_consumed = 0;
314 c->local_maxpacket = maxpack;
315 c->dynamic_window = 0;
317 c->remote_name = xstrdup(remote_name);
318 c->remote_window = 0;
319 c->remote_maxpacket = 0;
321 c->single_connection = 0;
322 c->detach_user = NULL;
325 c->confirm_ctx = NULL;
326 c->input_filter = NULL;
327 c->output_filter = NULL;
328 debug("channel %d: new [%s]", found, remote_name);
333 channel_find_maxfd(void)
339 for (i = 0; i < channels_alloc; i++) {
342 max = MAX(max, c->rfd);
343 max = MAX(max, c->wfd);
344 max = MAX(max, c->efd);
351 channel_close_fd(int *fdp)
353 int ret = 0, fd = *fdp;
358 if (fd == channel_max_fd)
359 channel_max_fd = channel_find_maxfd();
364 /* Close all channel fd/socket. */
366 channel_close_fds(Channel *c)
368 debug3("channel %d: close_fds r %d w %d e %d c %d",
369 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
371 channel_close_fd(&c->sock);
372 channel_close_fd(&c->ctl_fd);
373 channel_close_fd(&c->rfd);
374 channel_close_fd(&c->wfd);
375 channel_close_fd(&c->efd);
378 /* Free the channel and close its fd/socket. */
380 channel_free(Channel *c)
385 for (n = 0, i = 0; i < channels_alloc; i++)
388 debug("channel %d: free: %s, nchannels %u", c->self,
389 c->remote_name ? c->remote_name : "???", n);
391 s = channel_open_message();
392 debug3("channel %d: status: %s", c->self, s);
396 shutdown(c->sock, SHUT_RDWR);
398 shutdown(c->ctl_fd, SHUT_RDWR);
399 channel_close_fds(c);
400 buffer_free(&c->input);
401 buffer_free(&c->output);
402 buffer_free(&c->extended);
403 if (c->remote_name) {
404 xfree(c->remote_name);
405 c->remote_name = NULL;
407 channels[c->self] = NULL;
412 channel_free_all(void)
416 for (i = 0; i < channels_alloc; i++)
417 if (channels[i] != NULL)
418 channel_free(channels[i]);
422 * Closes the sockets/fds of all channels. This is used to close extra file
423 * descriptors after a fork.
426 channel_close_all(void)
430 for (i = 0; i < channels_alloc; i++)
431 if (channels[i] != NULL)
432 channel_close_fds(channels[i]);
436 * Stop listening to channels.
439 channel_stop_listening(void)
444 for (i = 0; i < channels_alloc; i++) {
448 case SSH_CHANNEL_AUTH_SOCKET:
449 case SSH_CHANNEL_PORT_LISTENER:
450 case SSH_CHANNEL_RPORT_LISTENER:
451 case SSH_CHANNEL_X11_LISTENER:
452 channel_close_fd(&c->sock);
461 * Returns true if no channel has too much buffered data, and false if one or
462 * more channel is overfull.
465 channel_not_very_much_buffered_data(void)
470 for (i = 0; i < channels_alloc; i++) {
472 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
475 buffer_len(&c->input) > packet_get_maxsize()) {
476 debug2("channel %d: big input buffer %d",
477 c->self, buffer_len(&c->input));
481 if (buffer_len(&c->output) > packet_get_maxsize()) {
482 debug2("channel %d: big output buffer %u > %u",
483 c->self, buffer_len(&c->output),
484 packet_get_maxsize());
492 /* Returns true if any channel is still open. */
494 channel_still_open(void)
499 for (i = 0; i < channels_alloc; i++) {
504 case SSH_CHANNEL_X11_LISTENER:
505 case SSH_CHANNEL_PORT_LISTENER:
506 case SSH_CHANNEL_RPORT_LISTENER:
507 case SSH_CHANNEL_CLOSED:
508 case SSH_CHANNEL_AUTH_SOCKET:
509 case SSH_CHANNEL_DYNAMIC:
510 case SSH_CHANNEL_CONNECTING:
511 case SSH_CHANNEL_ZOMBIE:
513 case SSH_CHANNEL_LARVAL:
515 fatal("cannot happen: SSH_CHANNEL_LARVAL");
517 case SSH_CHANNEL_OPENING:
518 case SSH_CHANNEL_OPEN:
519 case SSH_CHANNEL_X11_OPEN:
521 case SSH_CHANNEL_INPUT_DRAINING:
522 case SSH_CHANNEL_OUTPUT_DRAINING:
524 fatal("cannot happen: OUT_DRAIN");
527 fatal("channel_still_open: bad channel type %d", c->type);
534 /* Returns the id of an open channel suitable for keepaliving */
536 channel_find_open(void)
541 for (i = 0; i < channels_alloc; i++) {
543 if (c == NULL || c->remote_id < 0)
546 case SSH_CHANNEL_CLOSED:
547 case SSH_CHANNEL_DYNAMIC:
548 case SSH_CHANNEL_X11_LISTENER:
549 case SSH_CHANNEL_PORT_LISTENER:
550 case SSH_CHANNEL_RPORT_LISTENER:
551 case SSH_CHANNEL_OPENING:
552 case SSH_CHANNEL_CONNECTING:
553 case SSH_CHANNEL_ZOMBIE:
555 case SSH_CHANNEL_LARVAL:
556 case SSH_CHANNEL_AUTH_SOCKET:
557 case SSH_CHANNEL_OPEN:
558 case SSH_CHANNEL_X11_OPEN:
560 case SSH_CHANNEL_INPUT_DRAINING:
561 case SSH_CHANNEL_OUTPUT_DRAINING:
563 fatal("cannot happen: OUT_DRAIN");
566 fatal("channel_find_open: bad channel type %d", c->type);
575 * Returns a message describing the currently open forwarded connections,
576 * suitable for sending to the client. The message contains crlf pairs for
580 channel_open_message(void)
587 buffer_init(&buffer);
588 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
589 buffer_append(&buffer, buf, strlen(buf));
590 for (i = 0; i < channels_alloc; i++) {
595 case SSH_CHANNEL_X11_LISTENER:
596 case SSH_CHANNEL_PORT_LISTENER:
597 case SSH_CHANNEL_RPORT_LISTENER:
598 case SSH_CHANNEL_CLOSED:
599 case SSH_CHANNEL_AUTH_SOCKET:
600 case SSH_CHANNEL_ZOMBIE:
602 case SSH_CHANNEL_LARVAL:
603 case SSH_CHANNEL_OPENING:
604 case SSH_CHANNEL_CONNECTING:
605 case SSH_CHANNEL_DYNAMIC:
606 case SSH_CHANNEL_OPEN:
607 case SSH_CHANNEL_X11_OPEN:
608 case SSH_CHANNEL_INPUT_DRAINING:
609 case SSH_CHANNEL_OUTPUT_DRAINING:
610 snprintf(buf, sizeof buf,
611 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
612 c->self, c->remote_name,
613 c->type, c->remote_id,
614 c->istate, buffer_len(&c->input),
615 c->ostate, buffer_len(&c->output),
616 c->rfd, c->wfd, c->ctl_fd);
617 buffer_append(&buffer, buf, strlen(buf));
620 fatal("channel_open_message: bad channel type %d", c->type);
624 buffer_append(&buffer, "\0", 1);
625 cp = xstrdup(buffer_ptr(&buffer));
626 buffer_free(&buffer);
631 channel_send_open(int id)
633 Channel *c = channel_lookup(id);
636 logit("channel_send_open: %d: bad id", id);
639 debug2("channel %d: send open", id);
640 packet_start(SSH2_MSG_CHANNEL_OPEN);
641 packet_put_cstring(c->ctype);
642 packet_put_int(c->self);
643 packet_put_int(c->local_window);
644 packet_put_int(c->local_maxpacket);
649 channel_request_start(int id, char *service, int wantconfirm)
651 Channel *c = channel_lookup(id);
654 logit("channel_request_start: %d: unknown channel id", id);
657 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
658 packet_start(SSH2_MSG_CHANNEL_REQUEST);
659 packet_put_int(c->remote_id);
660 packet_put_cstring(service);
661 packet_put_char(wantconfirm);
665 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
667 Channel *c = channel_lookup(id);
670 logit("channel_register_comfirm: %d: bad id", id);
674 c->confirm_ctx = ctx;
678 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
680 Channel *c = channel_by_id(id);
683 logit("channel_register_cleanup: %d: bad id", id);
687 c->detach_close = do_close;
691 channel_cancel_cleanup(int id)
693 Channel *c = channel_by_id(id);
696 logit("channel_cancel_cleanup: %d: bad id", id);
699 c->detach_user = NULL;
704 channel_register_filter(int id, channel_infilter_fn *ifn,
705 channel_outfilter_fn *ofn)
707 Channel *c = channel_lookup(id);
710 logit("channel_register_filter: %d: bad id", id);
713 c->input_filter = ifn;
714 c->output_filter = ofn;
718 channel_set_fds(int id, int rfd, int wfd, int efd,
719 int extusage, int nonblock, u_int window_max)
721 Channel *c = channel_lookup(id);
723 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
724 fatal("channel_activate for non-larval channel %d.", id);
725 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
726 c->type = SSH_CHANNEL_OPEN;
727 c->local_window = c->local_window_max = window_max;
728 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
729 packet_put_int(c->remote_id);
730 packet_put_int(c->local_window);
735 * 'channel_pre*' are called just before select() to add any bits relevant to
736 * channels in the select bitmasks.
739 * 'channel_post*': perform any appropriate operations for channels which
740 * have events pending.
742 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
743 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
744 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
748 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
750 FD_SET(c->sock, readset);
755 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
757 debug3("channel %d: waiting for connection", c->self);
758 FD_SET(c->sock, writeset);
762 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
764 if (buffer_len(&c->input) < packet_get_maxsize())
765 FD_SET(c->sock, readset);
766 if (buffer_len(&c->output) > 0)
767 FD_SET(c->sock, writeset);
770 int channel_tcpwinsz () {
771 u_int32_t tcpwinsz = 0;
772 socklen_t optsz = sizeof(tcpwinsz);
774 if(!packet_connection_is_on_socket())
776 ret = getsockopt(packet_get_connection_in(),
777 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
778 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN)
779 tcpwinsz = BUFFER_MAX_LEN_HPN;
780 debug2("tcpwinsz: %d for connection: %d", tcpwinsz,
781 packet_get_connection_in());
786 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
788 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
790 /* check buffer limits */
792 c->tcpwinsz = channel_tcpwinsz();
793 if (c->dynamic_window > 0)
794 c->tcpwinsz = channel_tcpwinsz();
796 limit = MIN(limit, 2 * c->tcpwinsz);
798 if (c->istate == CHAN_INPUT_OPEN &&
800 buffer_len(&c->input) < limit &&
801 buffer_check_alloc(&c->input, CHAN_RBUF))
802 FD_SET(c->rfd, readset);
803 if (c->ostate == CHAN_OUTPUT_OPEN ||
804 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
805 if (buffer_len(&c->output) > 0) {
806 FD_SET(c->wfd, writeset);
807 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
808 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
809 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
810 c->self, c->efd, buffer_len(&c->extended));
815 /** XXX check close conditions, too */
816 if (compat20 && c->efd != -1) {
817 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
818 buffer_len(&c->extended) > 0)
819 FD_SET(c->efd, writeset);
820 else if (!(c->flags & CHAN_EOF_SENT) &&
821 c->extended_usage == CHAN_EXTENDED_READ &&
822 buffer_len(&c->extended) < c->remote_window)
823 FD_SET(c->efd, readset);
825 /* XXX: What about efd? races? */
826 if (compat20 && c->ctl_fd != -1 &&
827 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
828 FD_SET(c->ctl_fd, readset);
833 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
835 if (buffer_len(&c->input) == 0) {
836 packet_start(SSH_MSG_CHANNEL_CLOSE);
837 packet_put_int(c->remote_id);
839 c->type = SSH_CHANNEL_CLOSED;
840 debug2("channel %d: closing after input drain.", c->self);
846 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
848 if (buffer_len(&c->output) == 0)
851 FD_SET(c->sock, writeset);
855 * This is a special state for X11 authentication spoofing. An opened X11
856 * connection (when authentication spoofing is being done) remains in this
857 * state until the first packet has been completely read. The authentication
858 * data in that packet is then substituted by the real data if it matches the
859 * fake data, and the channel is put into normal mode.
860 * XXX All this happens at the client side.
861 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
864 x11_open_helper(Buffer *b)
867 u_int proto_len, data_len;
869 /* Check if the fixed size part of the packet is in buffer. */
870 if (buffer_len(b) < 12)
873 /* Parse the lengths of variable-length fields. */
875 if (ucp[0] == 0x42) { /* Byte order MSB first. */
876 proto_len = 256 * ucp[6] + ucp[7];
877 data_len = 256 * ucp[8] + ucp[9];
878 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
879 proto_len = ucp[6] + 256 * ucp[7];
880 data_len = ucp[8] + 256 * ucp[9];
882 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
887 /* Check if the whole packet is in buffer. */
889 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
892 /* Check if authentication protocol matches. */
893 if (proto_len != strlen(x11_saved_proto) ||
894 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
895 debug2("X11 connection uses different authentication protocol.");
898 /* Check if authentication data matches our fake data. */
899 if (data_len != x11_fake_data_len ||
900 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
901 x11_fake_data, x11_fake_data_len) != 0) {
902 debug2("X11 auth data does not match fake data.");
905 /* Check fake data length */
906 if (x11_fake_data_len != x11_saved_data_len) {
907 error("X11 fake_data_len %d != saved_data_len %d",
908 x11_fake_data_len, x11_saved_data_len);
912 * Received authentication protocol and data match
913 * our fake data. Substitute the fake data with real
916 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
917 x11_saved_data, x11_saved_data_len);
922 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
924 int ret = x11_open_helper(&c->output);
927 /* Start normal processing for the channel. */
928 c->type = SSH_CHANNEL_OPEN;
929 channel_pre_open_13(c, readset, writeset);
930 } else if (ret == -1) {
932 * We have received an X11 connection that has bad
933 * authentication information.
935 logit("X11 connection rejected because of wrong authentication.");
936 buffer_clear(&c->input);
937 buffer_clear(&c->output);
938 channel_close_fd(&c->sock);
940 c->type = SSH_CHANNEL_CLOSED;
941 packet_start(SSH_MSG_CHANNEL_CLOSE);
942 packet_put_int(c->remote_id);
948 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
950 int ret = x11_open_helper(&c->output);
952 /* c->force_drain = 1; */
955 c->type = SSH_CHANNEL_OPEN;
956 channel_pre_open(c, readset, writeset);
957 } else if (ret == -1) {
958 logit("X11 connection rejected because of wrong authentication.");
959 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
961 buffer_clear(&c->input);
963 buffer_clear(&c->output);
964 /* for proto v1, the peer will send an IEOF */
966 chan_write_failed(c);
968 c->type = SSH_CHANNEL_OPEN;
969 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
973 /* try to decode a socks4 header */
976 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
979 u_int len, have, i, found;
985 struct in_addr dest_addr;
988 debug2("channel %d: decode socks4", c->self);
990 have = buffer_len(&c->input);
991 len = sizeof(s4_req);
994 p = buffer_ptr(&c->input);
995 for (found = 0, i = len; i < have; i++) {
1001 /* the peer is probably sending garbage */
1002 debug("channel %d: decode socks4: too long",
1009 buffer_get(&c->input, (char *)&s4_req.version, 1);
1010 buffer_get(&c->input, (char *)&s4_req.command, 1);
1011 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1012 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1013 have = buffer_len(&c->input);
1014 p = buffer_ptr(&c->input);
1016 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1018 fatal("channel %d: decode socks4: len %d > have %d",
1019 c->self, len, have);
1020 strlcpy(username, p, sizeof(username));
1021 buffer_consume(&c->input, len);
1022 buffer_consume(&c->input, 1); /* trailing '\0' */
1024 host = inet_ntoa(s4_req.dest_addr);
1025 strlcpy(c->path, host, sizeof(c->path));
1026 c->host_port = ntohs(s4_req.dest_port);
1028 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1029 c->self, host, c->host_port, s4_req.command);
1031 if (s4_req.command != 1) {
1032 debug("channel %d: cannot handle: socks4 cn %d",
1033 c->self, s4_req.command);
1036 s4_rsp.version = 0; /* vn: 0 for reply */
1037 s4_rsp.command = 90; /* cd: req granted */
1038 s4_rsp.dest_port = 0; /* ignored */
1039 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
1040 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1044 /* try to decode a socks5 header */
1045 #define SSH_SOCKS5_AUTHDONE 0x1000
1046 #define SSH_SOCKS5_NOAUTH 0x00
1047 #define SSH_SOCKS5_IPV4 0x01
1048 #define SSH_SOCKS5_DOMAIN 0x03
1049 #define SSH_SOCKS5_IPV6 0x04
1050 #define SSH_SOCKS5_CONNECT 0x01
1051 #define SSH_SOCKS5_SUCCESS 0x00
1055 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1063 u_int16_t dest_port;
1064 u_char *p, dest_addr[255+1];
1065 u_int have, need, i, found, nmethods, addrlen, af;
1067 debug2("channel %d: decode socks5", c->self);
1068 p = buffer_ptr(&c->input);
1071 have = buffer_len(&c->input);
1072 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1073 /* format: ver | nmethods | methods */
1077 if (have < nmethods + 2)
1079 /* look for method: "NO AUTHENTICATION REQUIRED" */
1080 for (found = 0, i = 2; i < nmethods + 2; i++) {
1081 if (p[i] == SSH_SOCKS5_NOAUTH) {
1087 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1091 buffer_consume(&c->input, nmethods + 2);
1092 buffer_put_char(&c->output, 0x05); /* version */
1093 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1094 FD_SET(c->sock, writeset);
1095 c->flags |= SSH_SOCKS5_AUTHDONE;
1096 debug2("channel %d: socks5 auth done", c->self);
1097 return 0; /* need more */
1099 debug2("channel %d: socks5 post auth", c->self);
1100 if (have < sizeof(s5_req)+1)
1101 return 0; /* need more */
1102 memcpy(&s5_req, p, sizeof(s5_req));
1103 if (s5_req.version != 0x05 ||
1104 s5_req.command != SSH_SOCKS5_CONNECT ||
1105 s5_req.reserved != 0x00) {
1106 debug2("channel %d: only socks5 connect supported", c->self);
1109 switch (s5_req.atyp){
1110 case SSH_SOCKS5_IPV4:
1114 case SSH_SOCKS5_DOMAIN:
1115 addrlen = p[sizeof(s5_req)];
1118 case SSH_SOCKS5_IPV6:
1123 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1126 need = sizeof(s5_req) + addrlen + 2;
1127 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1131 buffer_consume(&c->input, sizeof(s5_req));
1132 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1133 buffer_consume(&c->input, 1); /* host string length */
1134 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1135 buffer_get(&c->input, (char *)&dest_port, 2);
1136 dest_addr[addrlen] = '\0';
1137 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1138 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1139 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1141 c->host_port = ntohs(dest_port);
1143 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1144 c->self, c->path, c->host_port, s5_req.command);
1146 s5_rsp.version = 0x05;
1147 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1148 s5_rsp.reserved = 0; /* ignored */
1149 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1150 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1151 dest_port = 0; /* ignored */
1153 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1154 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1155 buffer_append(&c->output, &dest_port, sizeof(dest_port));
1159 /* dynamic port forwarding */
1161 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1167 have = buffer_len(&c->input);
1169 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1170 /* buffer_dump(&c->input); */
1171 /* check if the fixed size part of the packet is in buffer. */
1174 FD_SET(c->sock, readset);
1177 /* try to guess the protocol */
1178 p = buffer_ptr(&c->input);
1181 ret = channel_decode_socks4(c, readset, writeset);
1184 ret = channel_decode_socks5(c, readset, writeset);
1192 } else if (ret == 0) {
1193 debug2("channel %d: pre_dynamic: need more", c->self);
1195 FD_SET(c->sock, readset);
1197 /* switch to the next state */
1198 c->type = SSH_CHANNEL_OPENING;
1199 port_open_helper(c, "direct-tcpip");
1203 /* This is our fake X11 server socket. */
1206 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1209 struct sockaddr addr;
1212 char buf[16384], *remote_ipaddr;
1215 if (FD_ISSET(c->sock, readset)) {
1216 debug("X11 connection requested.");
1217 addrlen = sizeof(addr);
1218 newsock = accept(c->sock, &addr, &addrlen);
1219 if (c->single_connection) {
1220 debug2("single_connection: closing X11 listener.");
1221 channel_close_fd(&c->sock);
1225 error("accept: %.100s", strerror(errno));
1228 set_nodelay(newsock);
1229 remote_ipaddr = get_peer_ipaddr(newsock);
1230 remote_port = get_peer_port(newsock);
1231 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1232 remote_ipaddr, remote_port);
1234 nc = channel_new("accepted x11 socket",
1235 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1236 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1238 packet_start(SSH2_MSG_CHANNEL_OPEN);
1239 packet_put_cstring("x11");
1240 packet_put_int(nc->self);
1241 packet_put_int(nc->local_window_max);
1242 packet_put_int(nc->local_maxpacket);
1243 /* originator ipaddr and port */
1244 packet_put_cstring(remote_ipaddr);
1245 if (datafellows & SSH_BUG_X11FWD) {
1246 debug2("ssh2 x11 bug compat mode");
1248 packet_put_int(remote_port);
1252 packet_start(SSH_SMSG_X11_OPEN);
1253 packet_put_int(nc->self);
1254 if (packet_get_protocol_flags() &
1255 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1256 packet_put_cstring(buf);
1259 xfree(remote_ipaddr);
1264 port_open_helper(Channel *c, char *rtype)
1268 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1269 int remote_port = get_peer_port(c->sock);
1271 direct = (strcmp(rtype, "direct-tcpip") == 0);
1273 snprintf(buf, sizeof buf,
1274 "%s: listening port %d for %.100s port %d, "
1275 "connect from %.200s port %d",
1276 rtype, c->listening_port, c->path, c->host_port,
1277 remote_ipaddr, remote_port);
1279 xfree(c->remote_name);
1280 c->remote_name = xstrdup(buf);
1283 packet_start(SSH2_MSG_CHANNEL_OPEN);
1284 packet_put_cstring(rtype);
1285 packet_put_int(c->self);
1286 packet_put_int(c->local_window_max);
1287 packet_put_int(c->local_maxpacket);
1289 /* target host, port */
1290 packet_put_cstring(c->path);
1291 packet_put_int(c->host_port);
1293 /* listen address, port */
1294 packet_put_cstring(c->path);
1295 packet_put_int(c->listening_port);
1297 /* originator host and port */
1298 packet_put_cstring(remote_ipaddr);
1299 packet_put_int((u_int)remote_port);
1302 packet_start(SSH_MSG_PORT_OPEN);
1303 packet_put_int(c->self);
1304 packet_put_cstring(c->path);
1305 packet_put_int(c->host_port);
1306 if (packet_get_protocol_flags() &
1307 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1308 packet_put_cstring(c->remote_name);
1311 xfree(remote_ipaddr);
1315 channel_set_reuseaddr(int fd)
1320 * Set socket options.
1321 * Allow local port reuse in TIME_WAIT.
1323 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1324 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1328 * This socket is listening for connections to a forwarded TCP/IP port.
1332 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1335 struct sockaddr addr;
1336 int newsock, nextstate;
1340 if (FD_ISSET(c->sock, readset)) {
1341 debug("Connection to port %d forwarding "
1342 "to %.100s port %d requested.",
1343 c->listening_port, c->path, c->host_port);
1345 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1346 nextstate = SSH_CHANNEL_OPENING;
1347 rtype = "forwarded-tcpip";
1349 if (c->host_port == 0) {
1350 nextstate = SSH_CHANNEL_DYNAMIC;
1351 rtype = "dynamic-tcpip";
1353 nextstate = SSH_CHANNEL_OPENING;
1354 rtype = "direct-tcpip";
1358 addrlen = sizeof(addr);
1359 newsock = accept(c->sock, &addr, &addrlen);
1361 error("accept: %.100s", strerror(errno));
1364 set_nodelay(newsock);
1365 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1366 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1367 nc->listening_port = c->listening_port;
1368 nc->host_port = c->host_port;
1369 strlcpy(nc->path, c->path, sizeof(nc->path));
1371 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1373 * do not call the channel_post handler until
1374 * this flag has been reset by a pre-handler.
1375 * otherwise the FD_ISSET calls might overflow
1379 port_open_helper(nc, rtype);
1385 * This is the authentication agent socket listening for connections from
1390 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1394 struct sockaddr addr;
1397 if (FD_ISSET(c->sock, readset)) {
1398 addrlen = sizeof(addr);
1399 newsock = accept(c->sock, &addr, &addrlen);
1401 error("accept from auth socket: %.100s", strerror(errno));
1404 nc = channel_new("accepted auth socket",
1405 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1406 c->local_window_max, c->local_maxpacket,
1407 0, "accepted auth socket", 1);
1409 packet_start(SSH2_MSG_CHANNEL_OPEN);
1410 packet_put_cstring("auth-agent@openssh.com");
1411 packet_put_int(nc->self);
1412 packet_put_int(c->local_window_max);
1413 packet_put_int(c->local_maxpacket);
1415 packet_start(SSH_SMSG_AGENT_OPEN);
1416 packet_put_int(nc->self);
1424 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1427 socklen_t sz = sizeof(err);
1429 if (FD_ISSET(c->sock, writeset)) {
1430 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1432 error("getsockopt SO_ERROR failed");
1435 debug("channel %d: connected", c->self);
1436 c->type = SSH_CHANNEL_OPEN;
1438 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1439 packet_put_int(c->remote_id);
1440 packet_put_int(c->self);
1441 packet_put_int(c->local_window);
1442 packet_put_int(c->local_maxpacket);
1444 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1445 packet_put_int(c->remote_id);
1446 packet_put_int(c->self);
1449 debug("channel %d: not connected: %s",
1450 c->self, strerror(err));
1452 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1453 packet_put_int(c->remote_id);
1454 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1455 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1456 packet_put_cstring(strerror(err));
1457 packet_put_cstring("");
1460 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1461 packet_put_int(c->remote_id);
1471 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1473 char buf[CHAN_RBUF];
1476 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1477 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1479 len = read(c->rfd, buf, sizeof(buf));
1480 if (len < 0 && (errno == EINTR || (errno == EAGAIN && !force)))
1482 #ifndef PTY_ZEROREAD
1485 if ((!c->isatty && len <= 0) ||
1486 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1488 debug2("channel %d: read<=0 rfd %d len %d",
1489 c->self, c->rfd, len);
1490 if (c->type != SSH_CHANNEL_OPEN) {
1491 debug2("channel %d: not open", c->self);
1494 } else if (compat13) {
1495 buffer_clear(&c->output);
1496 c->type = SSH_CHANNEL_INPUT_DRAINING;
1497 debug2("channel %d: input draining.", c->self);
1499 chan_read_failed(c);
1503 if (c->input_filter != NULL) {
1504 if (c->input_filter(c, buf, len) == -1) {
1505 debug2("channel %d: filter stops", c->self);
1506 chan_read_failed(c);
1508 } else if (c->datagram) {
1509 buffer_put_string(&c->input, buf, len);
1511 buffer_append(&c->input, buf, len);
1519 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1522 u_char *data = NULL, *buf;
1526 /* Send buffered output data to the socket. */
1528 FD_ISSET(c->wfd, writeset) &&
1529 buffer_len(&c->output) > 0) {
1530 if (c->output_filter != NULL) {
1531 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1532 debug2("channel %d: filter stops", c->self);
1533 if (c->type != SSH_CHANNEL_OPEN)
1536 chan_write_failed(c);
1539 } else if (c->datagram) {
1540 buf = data = buffer_get_string(&c->output, &dlen);
1542 buf = data = buffer_ptr(&c->output);
1543 dlen = buffer_len(&c->output);
1547 /* ignore truncated writes, datagrams might get lost */
1548 c->local_consumed += dlen + 4;
1549 len = write(c->wfd, buf, dlen);
1551 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1554 if (c->type != SSH_CHANNEL_OPEN)
1557 chan_write_failed(c);
1563 /* XXX: Later AIX versions can't push as much data to tty */
1564 if (compat20 && c->wfd_isatty)
1565 dlen = MIN(dlen, 8*1024);
1568 len = write(c->wfd, buf, dlen);
1569 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1572 if (c->type != SSH_CHANNEL_OPEN) {
1573 debug2("channel %d: not open", c->self);
1576 } else if (compat13) {
1577 buffer_clear(&c->output);
1578 debug2("channel %d: input draining.", c->self);
1579 c->type = SSH_CHANNEL_INPUT_DRAINING;
1581 chan_write_failed(c);
1585 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1586 if (tcgetattr(c->wfd, &tio) == 0 &&
1587 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1589 * Simulate echo to reduce the impact of
1590 * traffic analysis. We need to match the
1591 * size of a SSH2_MSG_CHANNEL_DATA message
1592 * (4 byte channel id + buf)
1594 packet_send_ignore(4 + len);
1598 buffer_consume(&c->output, len);
1599 if (compat20 && len > 0) {
1600 c->local_consumed += len;
1607 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1609 char buf[CHAN_RBUF];
1612 /** XXX handle drain efd, too */
1614 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1615 FD_ISSET(c->efd, writeset) &&
1616 buffer_len(&c->extended) > 0) {
1617 len = write(c->efd, buffer_ptr(&c->extended),
1618 buffer_len(&c->extended));
1619 debug2("channel %d: written %d to efd %d",
1620 c->self, len, c->efd);
1621 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1624 debug2("channel %d: closing write-efd %d",
1626 channel_close_fd(&c->efd);
1628 buffer_consume(&c->extended, len);
1629 c->local_consumed += len;
1631 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1632 (c->detach_close || FD_ISSET(c->efd, readset))) {
1633 len = read(c->efd, buf, sizeof(buf));
1634 debug2("channel %d: read %d from efd %d",
1635 c->self, len, c->efd);
1636 if (len < 0 && (errno == EINTR ||
1637 (errno == EAGAIN && !c->detach_close)))
1640 debug2("channel %d: closing read-efd %d",
1642 channel_close_fd(&c->efd);
1644 buffer_append(&c->extended, buf, len);
1653 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1658 /* Monitor control fd to detect if the slave client exits */
1659 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1660 len = read(c->ctl_fd, buf, sizeof(buf));
1661 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1664 debug2("channel %d: ctl read<=0", c->self);
1665 if (c->type != SSH_CHANNEL_OPEN) {
1666 debug2("channel %d: not open", c->self);
1670 chan_read_failed(c);
1671 chan_write_failed(c);
1675 fatal("%s: unexpected data on ctl fd", __func__);
1681 channel_check_window(Channel *c)
1683 if (c->type == SSH_CHANNEL_OPEN &&
1684 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1685 ((c->local_window_max - c->local_window >
1686 c->local_maxpacket*3) ||
1687 c->local_window < c->local_window_max/2) &&
1688 c->local_consumed > 0) {
1690 /* adjust max window size if we are in a dynamic environment */
1691 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1692 addition = c->tcpwinsz - c->local_window_max;
1693 c->local_window_max += addition;
1695 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1696 packet_put_int(c->remote_id);
1697 packet_put_int(c->local_consumed + addition);
1699 debug2("channel %d: window %d sent adjust %d",
1700 c->self, c->local_window,
1702 c->local_window += c->local_consumed + addition;
1703 c->local_consumed = 0;
1709 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1713 channel_handle_rfd(c, readset, writeset);
1714 channel_handle_wfd(c, readset, writeset);
1717 channel_handle_efd(c, readset, writeset);
1718 channel_handle_ctl(c, readset, writeset);
1719 channel_check_window(c);
1724 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1728 /* Send buffered output data to the socket. */
1729 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1730 len = write(c->sock, buffer_ptr(&c->output),
1731 buffer_len(&c->output));
1733 buffer_clear(&c->output);
1735 buffer_consume(&c->output, len);
1740 channel_handler_init_20(void)
1742 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1743 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1744 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1745 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1746 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1747 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1748 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1749 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1751 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1752 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1753 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1754 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1755 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1756 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1757 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1761 channel_handler_init_13(void)
1763 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1764 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1765 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1766 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1767 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1768 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1769 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1770 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1771 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1773 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1774 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1775 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1776 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1777 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1778 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1779 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1783 channel_handler_init_15(void)
1785 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1786 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1787 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1788 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1789 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1790 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1791 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1793 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1794 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1795 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1796 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1797 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1798 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1802 channel_handler_init(void)
1806 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1807 channel_pre[i] = NULL;
1808 channel_post[i] = NULL;
1811 channel_handler_init_20();
1813 channel_handler_init_13();
1815 channel_handler_init_15();
1818 /* gc dead channels */
1820 channel_garbage_collect(Channel *c)
1824 if (c->detach_user != NULL) {
1825 if (!chan_is_dead(c, c->detach_close))
1827 debug2("channel %d: gc: notify user", c->self);
1828 c->detach_user(c->self, NULL);
1829 /* if we still have a callback */
1830 if (c->detach_user != NULL)
1832 debug2("channel %d: gc: user detached", c->self);
1834 if (!chan_is_dead(c, 1))
1836 debug2("channel %d: garbage collecting", c->self);
1841 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1843 static int did_init = 0;
1848 channel_handler_init();
1851 for (i = 0; i < channels_alloc; i++) {
1855 if (ftab[c->type] != NULL)
1856 (*ftab[c->type])(c, readset, writeset);
1857 channel_garbage_collect(c);
1862 * Allocate/update select bitmasks and add any bits relevant to channels in
1866 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1867 u_int *nallocp, int rekeying)
1869 u_int n, sz, nfdset;
1871 n = MAX(*maxfdp, channel_max_fd);
1873 nfdset = howmany(n+1, NFDBITS);
1874 /* Explicitly test here, because xrealloc isn't always called */
1875 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1876 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1877 sz = nfdset * sizeof(fd_mask);
1879 /* perhaps check sz < nalloc/2 and shrink? */
1880 if (*readsetp == NULL || sz > *nallocp) {
1881 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1882 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1886 memset(*readsetp, 0, sz);
1887 memset(*writesetp, 0, sz);
1890 channel_handler(channel_pre, *readsetp, *writesetp);
1894 * After select, perform any appropriate operations for channels which have
1898 channel_after_select(fd_set *readset, fd_set *writeset)
1900 channel_handler(channel_post, readset, writeset);
1904 /* If there is data to send to the connection, enqueue some of it now. */
1906 channel_output_poll(void)
1911 for (i = 0; i < channels_alloc; i++) {
1917 * We are only interested in channels that can have buffered
1921 if (c->type != SSH_CHANNEL_OPEN &&
1922 c->type != SSH_CHANNEL_INPUT_DRAINING)
1925 if (c->type != SSH_CHANNEL_OPEN)
1929 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1930 /* XXX is this true? */
1931 debug3("channel %d: will not send data after close", c->self);
1935 /* Get the amount of buffered data for this channel. */
1936 if ((c->istate == CHAN_INPUT_OPEN ||
1937 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1938 (len = buffer_len(&c->input)) > 0) {
1944 data = buffer_get_string(&c->input,
1946 packet_start(SSH2_MSG_CHANNEL_DATA);
1947 packet_put_int(c->remote_id);
1948 packet_put_string(data, dlen);
1950 c->remote_window -= dlen + 4;
1956 * Send some data for the other side over the secure
1960 if (len > c->remote_window)
1961 len = c->remote_window;
1962 if (len > c->remote_maxpacket)
1963 len = c->remote_maxpacket;
1965 if (packet_is_interactive()) {
1969 /* Keep the packets at reasonable size. */
1970 if (len > packet_get_maxsize()/2)
1971 len = packet_get_maxsize()/2;
1975 packet_start(compat20 ?
1976 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1977 packet_put_int(c->remote_id);
1978 packet_put_string(buffer_ptr(&c->input), len);
1980 buffer_consume(&c->input, len);
1981 c->remote_window -= len;
1983 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1985 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1987 * input-buffer is empty and read-socket shutdown:
1988 * tell peer, that we will not send more data: send IEOF.
1989 * hack for extended data: delay EOF if EFD still in use.
1991 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1992 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1993 c->self, c->efd, buffer_len(&c->extended));
1997 /* Send extended data, i.e. stderr */
1999 !(c->flags & CHAN_EOF_SENT) &&
2000 c->remote_window > 0 &&
2001 (len = buffer_len(&c->extended)) > 0 &&
2002 c->extended_usage == CHAN_EXTENDED_READ) {
2003 debug2("channel %d: rwin %u elen %u euse %d",
2004 c->self, c->remote_window, buffer_len(&c->extended),
2006 if (len > c->remote_window)
2007 len = c->remote_window;
2008 if (len > c->remote_maxpacket)
2009 len = c->remote_maxpacket;
2010 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2011 packet_put_int(c->remote_id);
2012 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2013 packet_put_string(buffer_ptr(&c->extended), len);
2015 buffer_consume(&c->extended, len);
2016 c->remote_window -= len;
2017 debug2("channel %d: sent ext data %d", c->self, len);
2023 /* -- protocol input */
2027 channel_input_data(int type, u_int32_t seq, void *ctxt)
2034 /* Get the channel number and verify it. */
2035 id = packet_get_int();
2036 c = channel_lookup(id);
2038 packet_disconnect("Received data for nonexistent channel %d.", id);
2040 /* Ignore any data for non-open channels (might happen on close) */
2041 if (c->type != SSH_CHANNEL_OPEN &&
2042 c->type != SSH_CHANNEL_X11_OPEN)
2046 data = packet_get_string(&data_len);
2049 * Ignore data for protocol > 1.3 if output end is no longer open.
2050 * For protocol 2 the sending side is reducing its window as it sends
2051 * data, so we must 'fake' consumption of the data in order to ensure
2052 * that window updates are sent back. Otherwise the connection might
2055 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2057 c->local_window -= data_len;
2058 c->local_consumed += data_len;
2065 if (data_len > c->local_maxpacket) {
2066 logit("channel %d: rcvd big packet %d, maxpack %d",
2067 c->self, data_len, c->local_maxpacket);
2069 if (data_len > c->local_window) {
2070 logit("channel %d: rcvd too much data %d, win %d",
2071 c->self, data_len, c->local_window);
2075 c->local_window -= data_len;
2079 buffer_put_string(&c->output, data, data_len);
2081 buffer_append(&c->output, data, data_len);
2087 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2091 u_int data_len, tcode;
2094 /* Get the channel number and verify it. */
2095 id = packet_get_int();
2096 c = channel_lookup(id);
2099 packet_disconnect("Received extended_data for bad channel %d.", id);
2100 if (c->type != SSH_CHANNEL_OPEN) {
2101 logit("channel %d: ext data for non open", id);
2104 if (c->flags & CHAN_EOF_RCVD) {
2105 if (datafellows & SSH_BUG_EXTEOF)
2106 debug("channel %d: accepting ext data after eof", id);
2108 packet_disconnect("Received extended_data after EOF "
2109 "on channel %d.", id);
2111 tcode = packet_get_int();
2113 c->extended_usage != CHAN_EXTENDED_WRITE ||
2114 tcode != SSH2_EXTENDED_DATA_STDERR) {
2115 logit("channel %d: bad ext data", c->self);
2118 data = packet_get_string(&data_len);
2120 if (data_len > c->local_window) {
2121 logit("channel %d: rcvd too much extended_data %d, win %d",
2122 c->self, data_len, c->local_window);
2126 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2127 c->local_window -= data_len;
2128 buffer_append(&c->extended, data, data_len);
2134 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2139 id = packet_get_int();
2141 c = channel_lookup(id);
2143 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2146 /* XXX force input close */
2147 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2148 debug("channel %d: FORCE input drain", c->self);
2149 c->istate = CHAN_INPUT_WAIT_DRAIN;
2150 if (buffer_len(&c->input) == 0)
2158 channel_input_close(int type, u_int32_t seq, void *ctxt)
2163 id = packet_get_int();
2165 c = channel_lookup(id);
2167 packet_disconnect("Received close for nonexistent channel %d.", id);
2170 * Send a confirmation that we have closed the channel and no more
2171 * data is coming for it.
2173 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2174 packet_put_int(c->remote_id);
2178 * If the channel is in closed state, we have sent a close request,
2179 * and the other side will eventually respond with a confirmation.
2180 * Thus, we cannot free the channel here, because then there would be
2181 * no-one to receive the confirmation. The channel gets freed when
2182 * the confirmation arrives.
2184 if (c->type != SSH_CHANNEL_CLOSED) {
2186 * Not a closed channel - mark it as draining, which will
2187 * cause it to be freed later.
2189 buffer_clear(&c->input);
2190 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2194 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2197 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2199 int id = packet_get_int();
2200 Channel *c = channel_lookup(id);
2204 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2205 chan_rcvd_oclose(c);
2210 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2212 int id = packet_get_int();
2213 Channel *c = channel_lookup(id);
2217 packet_disconnect("Received close confirmation for "
2218 "out-of-range channel %d.", id);
2219 if (c->type != SSH_CHANNEL_CLOSED)
2220 packet_disconnect("Received close confirmation for "
2221 "non-closed channel %d (type %d).", id, c->type);
2227 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2232 id = packet_get_int();
2233 c = channel_lookup(id);
2235 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2236 packet_disconnect("Received open confirmation for "
2237 "non-opening channel %d.", id);
2238 remote_id = packet_get_int();
2239 /* Record the remote channel number and mark that the channel is now open. */
2240 c->remote_id = remote_id;
2241 c->type = SSH_CHANNEL_OPEN;
2244 c->remote_window = packet_get_int();
2245 c->remote_maxpacket = packet_get_int();
2247 debug2("callback start");
2248 c->confirm(c->self, c->confirm_ctx);
2249 debug2("callback done");
2251 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2252 c->remote_window, c->remote_maxpacket);
2258 reason2txt(int reason)
2261 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2262 return "administratively prohibited";
2263 case SSH2_OPEN_CONNECT_FAILED:
2264 return "connect failed";
2265 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2266 return "unknown channel type";
2267 case SSH2_OPEN_RESOURCE_SHORTAGE:
2268 return "resource shortage";
2270 return "unknown reason";
2275 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2278 char *msg = NULL, *lang = NULL;
2281 id = packet_get_int();
2282 c = channel_lookup(id);
2284 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2285 packet_disconnect("Received open failure for "
2286 "non-opening channel %d.", id);
2288 reason = packet_get_int();
2289 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2290 msg = packet_get_string(NULL);
2291 lang = packet_get_string(NULL);
2293 logit("channel %d: open failed: %s%s%s", id,
2294 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2301 /* Free the channel. This will also close the socket. */
2307 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2316 /* Get the channel number and verify it. */
2317 id = packet_get_int();
2318 c = channel_lookup(id);
2321 logit("Received window adjust for non-open channel %d.", id);
2324 adjust = packet_get_int();
2326 debug2("channel %d: rcvd adjust %u", id, adjust);
2327 c->remote_window += adjust;
2332 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2336 char *host, *originator_string;
2337 int remote_id, sock = -1;
2339 remote_id = packet_get_int();
2340 host = packet_get_string(NULL);
2341 host_port = packet_get_int();
2343 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2344 originator_string = packet_get_string(NULL);
2346 originator_string = xstrdup("unknown (remote did not supply name)");
2349 sock = channel_connect_to(host, host_port);
2351 c = channel_new("connected socket",
2352 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2353 originator_string, 1);
2354 c->remote_id = remote_id;
2356 xfree(originator_string);
2358 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2359 packet_put_int(remote_id);
2366 /* -- tcp forwarding */
2369 channel_set_af(int af)
2375 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2376 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2377 int hpn_disabled, int hpn_buffer_size)
2380 int sock, r, success = 0, wildcard = 0, is_client;
2381 struct addrinfo hints, *ai, *aitop;
2382 const char *host, *addr;
2383 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2385 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2386 listen_addr : host_to_connect;
2387 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2390 error("No forward host name.");
2393 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2394 error("Forward host name too long.");
2399 * Determine whether or not a port forward listens to loopback,
2400 * specified address or wildcard. On the client, a specified bind
2401 * address will always override gateway_ports. On the server, a
2402 * gateway_ports of 1 (``yes'') will override the client's
2403 * specification and force a wildcard bind, whereas a value of 2
2404 * (``clientspecified'') will bind to whatever address the client
2407 * Special-case listen_addrs are:
2409 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2410 * "" (empty string), "*" -> wildcard v4/v6
2411 * "localhost" -> loopback v4/v6
2414 if (listen_addr == NULL) {
2415 /* No address specified: default to gateway_ports setting */
2418 } else if (gateway_ports || is_client) {
2419 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2420 strcmp(listen_addr, "0.0.0.0") == 0) ||
2421 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2422 (!is_client && gateway_ports == 1))
2424 else if (strcmp(listen_addr, "localhost") != 0)
2428 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2429 type, wildcard, (addr == NULL) ? "NULL" : addr);
2432 * getaddrinfo returns a loopback address if the hostname is
2433 * set to NULL and hints.ai_flags is not AI_PASSIVE
2435 memset(&hints, 0, sizeof(hints));
2436 hints.ai_family = IPv4or6;
2437 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2438 hints.ai_socktype = SOCK_STREAM;
2439 snprintf(strport, sizeof strport, "%d", listen_port);
2440 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2442 /* This really shouldn't happen */
2443 packet_disconnect("getaddrinfo: fatal error: %s",
2446 error("channel_setup_fwd_listener: "
2447 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2452 for (ai = aitop; ai; ai = ai->ai_next) {
2453 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2455 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2456 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2457 error("channel_setup_fwd_listener: getnameinfo failed");
2460 /* Create a port to listen for the host. */
2461 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2463 /* this is no error since kernel may not support ipv6 */
2464 verbose("socket: %.100s", strerror(errno));
2468 channel_set_reuseaddr(sock);
2470 debug("Local forwarding listening on %s port %s.", ntop, strport);
2472 /* Bind the socket to the address. */
2473 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2474 /* address can be in use ipv6 address is already bound */
2476 error("bind: %.100s", strerror(errno));
2478 verbose("bind: %.100s", strerror(errno));
2483 /* Start listening for connections on the socket. */
2484 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2485 error("listen: %.100s", strerror(errno));
2489 /* Allocate a channel number for the socket. */
2490 /* explicitly test for hpn disabled option. if true use smaller window size */
2492 c = channel_new("port listener", type, sock, sock, -1,
2493 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2494 0, "port listener", 1);
2496 c = channel_new("port listener", type, sock, sock, -1,
2497 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2498 0, "port listener", 1);
2499 strlcpy(c->path, host, sizeof(c->path));
2500 c->host_port = port_to_connect;
2501 c->listening_port = listen_port;
2505 error("channel_setup_fwd_listener: cannot listen to port: %d",
2507 freeaddrinfo(aitop);
2512 channel_cancel_rport_listener(const char *host, u_short port)
2517 for (i = 0; i < channels_alloc; i++) {
2518 Channel *c = channels[i];
2520 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2521 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2522 c->listening_port == port) {
2523 debug2("%s: close channel %d", __func__, i);
2532 /* protocol local port fwd, used by ssh (and sshd in v1) */
2534 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2535 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
2536 int hpn_disabled, int hpn_buffer_size)
2538 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2539 listen_host, listen_port, host_to_connect, port_to_connect,
2540 gateway_ports, hpn_disabled, hpn_buffer_size);
2543 /* protocol v2 remote port fwd, used by sshd */
2545 channel_setup_remote_fwd_listener(const char *listen_address,
2546 u_short listen_port, int gateway_ports, int hpn_disabled, int hpn_buffer_size)
2548 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2549 listen_address, listen_port, NULL, 0, gateway_ports,
2550 hpn_disabled, hpn_buffer_size);
2554 * Initiate forwarding of connections to port "port" on remote host through
2555 * the secure channel to host:port from local side.
2559 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2560 const char *host_to_connect, u_short port_to_connect)
2562 int type, success = 0;
2564 /* Record locally that connection to this host/port is permitted. */
2565 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2566 fatal("channel_request_remote_forwarding: too many forwards");
2568 /* Send the forward request to the remote side. */
2570 const char *address_to_bind;
2571 if (listen_host == NULL) {
2572 if (datafellows & SSH_BUG_RFWD_ADDR)
2573 address_to_bind = "127.0.0.1";
2575 address_to_bind = "localhost";
2576 } else if (*listen_host == '\0' ||
2577 strcmp(listen_host, "*") == 0) {
2578 if (datafellows & SSH_BUG_RFWD_ADDR)
2579 address_to_bind = "0.0.0.0";
2581 address_to_bind = "";
2583 address_to_bind = listen_host;
2585 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2586 packet_put_cstring("tcpip-forward");
2587 packet_put_char(1); /* boolean: want reply */
2588 packet_put_cstring(address_to_bind);
2589 packet_put_int(listen_port);
2591 packet_write_wait();
2592 /* Assume that server accepts the request */
2595 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2596 packet_put_int(listen_port);
2597 packet_put_cstring(host_to_connect);
2598 packet_put_int(port_to_connect);
2600 packet_write_wait();
2602 /* Wait for response from the remote side. */
2603 type = packet_read();
2605 case SSH_SMSG_SUCCESS:
2608 case SSH_SMSG_FAILURE:
2611 /* Unknown packet */
2612 packet_disconnect("Protocol error for port forward request:"
2613 "received packet type %d.", type);
2617 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2618 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2619 permitted_opens[num_permitted_opens].listen_port = listen_port;
2620 num_permitted_opens++;
2622 return (success ? 0 : -1);
2626 * Request cancellation of remote forwarding of connection host:port from
2630 channel_request_rforward_cancel(const char *host, u_short port)
2637 for (i = 0; i < num_permitted_opens; i++) {
2638 if (permitted_opens[i].host_to_connect != NULL &&
2639 permitted_opens[i].listen_port == port)
2642 if (i >= num_permitted_opens) {
2643 debug("%s: requested forward not found", __func__);
2646 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2647 packet_put_cstring("cancel-tcpip-forward");
2649 packet_put_cstring(host == NULL ? "" : host);
2650 packet_put_int(port);
2653 permitted_opens[i].listen_port = 0;
2654 permitted_opens[i].port_to_connect = 0;
2655 xfree(permitted_opens[i].host_to_connect);
2656 permitted_opens[i].host_to_connect = NULL;
2660 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2661 * listening for the port, and sends back a success reply (or disconnect
2662 * message if there was an error).
2665 channel_input_port_forward_request(int is_root, int gateway_ports,
2666 int hpn_disabled, int hpn_buffer_size)
2668 u_short port, host_port;
2672 /* Get arguments from the packet. */
2673 port = packet_get_int();
2674 hostname = packet_get_string(NULL);
2675 host_port = packet_get_int();
2679 * Check that an unprivileged user is not trying to forward a
2682 if (port < IPPORT_RESERVED && !is_root)
2684 "Requested forwarding of port %d but user is not root.",
2687 packet_disconnect("Dynamic forwarding denied.");
2690 /* Initiate forwarding */
2691 success = channel_setup_local_fwd_listener(NULL, port, hostname,
2692 host_port, gateway_ports, hpn_disabled, hpn_buffer_size);
2694 /* Free the argument string. */
2697 return (success ? 0 : -1);
2701 * Permits opening to any host/port if permitted_opens[] is empty. This is
2702 * usually called by the server, because the user could connect to any port
2703 * anyway, and the server has no way to know but to trust the client anyway.
2706 channel_permit_all_opens(void)
2708 if (num_permitted_opens == 0)
2709 all_opens_permitted = 1;
2713 channel_add_permitted_opens(char *host, int port)
2715 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2716 fatal("channel_add_permitted_opens: too many forwards");
2717 debug("allow port forwarding to host %s port %d", host, port);
2719 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2720 permitted_opens[num_permitted_opens].port_to_connect = port;
2721 num_permitted_opens++;
2723 all_opens_permitted = 0;
2727 channel_add_adm_permitted_opens(char *host, int port)
2729 if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2730 fatal("channel_add_adm_permitted_opens: too many forwards");
2731 debug("config allows port forwarding to host %s port %d", host, port);
2733 permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2735 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2736 return ++num_adm_permitted_opens;
2740 channel_clear_permitted_opens(void)
2744 for (i = 0; i < num_permitted_opens; i++)
2745 if (permitted_opens[i].host_to_connect != NULL)
2746 xfree(permitted_opens[i].host_to_connect);
2747 num_permitted_opens = 0;
2751 channel_clear_adm_permitted_opens(void)
2755 for (i = 0; i < num_adm_permitted_opens; i++)
2756 if (permitted_adm_opens[i].host_to_connect != NULL)
2757 xfree(permitted_adm_opens[i].host_to_connect);
2758 num_adm_permitted_opens = 0;
2761 /* return socket to remote host, port */
2763 connect_to(const char *host, u_short port)
2765 struct addrinfo hints, *ai, *aitop;
2766 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2770 memset(&hints, 0, sizeof(hints));
2771 hints.ai_family = IPv4or6;
2772 hints.ai_socktype = SOCK_STREAM;
2773 snprintf(strport, sizeof strport, "%d", port);
2774 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2775 error("connect_to %.100s: unknown host (%s)", host,
2776 gai_strerror(gaierr));
2779 for (ai = aitop; ai; ai = ai->ai_next) {
2780 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2782 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2783 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2784 error("connect_to: getnameinfo failed");
2787 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2789 if (ai->ai_next == NULL)
2790 error("socket: %.100s", strerror(errno));
2792 verbose("socket: %.100s", strerror(errno));
2795 if (set_nonblock(sock) == -1)
2796 fatal("%s: set_nonblock(%d)", __func__, sock);
2797 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2798 errno != EINPROGRESS) {
2799 error("connect_to %.100s port %s: %.100s", ntop, strport,
2802 continue; /* fail -- try next */
2804 break; /* success */
2807 freeaddrinfo(aitop);
2809 error("connect_to %.100s port %d: failed.", host, port);
2818 channel_connect_by_listen_address(u_short listen_port)
2822 for (i = 0; i < num_permitted_opens; i++)
2823 if (permitted_opens[i].host_to_connect != NULL &&
2824 permitted_opens[i].listen_port == listen_port)
2826 permitted_opens[i].host_to_connect,
2827 permitted_opens[i].port_to_connect);
2828 error("WARNING: Server requests forwarding for unknown listen_port %d",
2833 /* Check if connecting to that port is permitted and connect. */
2835 channel_connect_to(const char *host, u_short port)
2837 int i, permit, permit_adm = 1;
2839 permit = all_opens_permitted;
2841 for (i = 0; i < num_permitted_opens; i++)
2842 if (permitted_opens[i].host_to_connect != NULL &&
2843 permitted_opens[i].port_to_connect == port &&
2844 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2848 if (num_adm_permitted_opens > 0) {
2850 for (i = 0; i < num_adm_permitted_opens; i++)
2851 if (permitted_adm_opens[i].host_to_connect != NULL &&
2852 permitted_adm_opens[i].port_to_connect == port &&
2853 strcmp(permitted_adm_opens[i].host_to_connect, host)
2858 if (!permit || !permit_adm) {
2859 logit("Received request to connect to host %.100s port %d, "
2860 "but the request was denied.", host, port);
2863 return connect_to(host, port);
2867 channel_send_window_changes(void)
2872 for (i = 0; i < channels_alloc; i++) {
2873 if (channels[i] == NULL || !channels[i]->client_tty ||
2874 channels[i]->type != SSH_CHANNEL_OPEN)
2876 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2878 channel_request_start(i, "window-change", 0);
2879 packet_put_int((u_int)ws.ws_col);
2880 packet_put_int((u_int)ws.ws_row);
2881 packet_put_int((u_int)ws.ws_xpixel);
2882 packet_put_int((u_int)ws.ws_ypixel);
2887 /* -- X11 forwarding */
2890 * Creates an internet domain socket for listening for X11 connections.
2891 * Returns 0 and a suitable display number for the DISPLAY variable
2892 * stored in display_numberp , or -1 if an error occurs.
2895 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2896 int single_connection, u_int *display_numberp, int **chanids,
2897 int hpn_disabled, int hpn_buffer_size)
2900 int display_number, sock;
2902 struct addrinfo hints, *ai, *aitop;
2903 char strport[NI_MAXSERV];
2904 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2906 if (chanids == NULL)
2909 for (display_number = x11_display_offset;
2910 display_number < MAX_DISPLAYS;
2912 port = 6000 + display_number;
2913 memset(&hints, 0, sizeof(hints));
2914 hints.ai_family = IPv4or6;
2915 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2916 hints.ai_socktype = SOCK_STREAM;
2917 snprintf(strport, sizeof strport, "%d", port);
2918 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2919 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2922 for (ai = aitop; ai; ai = ai->ai_next) {
2923 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2925 sock = socket(ai->ai_family, ai->ai_socktype,
2928 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2929 error("socket: %.100s", strerror(errno));
2930 freeaddrinfo(aitop);
2933 debug("x11_create_display_inet: Socket family %d not supported",
2939 if (ai->ai_family == AF_INET6) {
2941 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2942 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2945 channel_set_reuseaddr(sock);
2946 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2947 debug2("bind port %d: %.100s", port, strerror(errno));
2953 for (n = 0; n < num_socks; n++) {
2959 socks[num_socks++] = sock;
2960 #ifndef DONT_TRY_OTHER_AF
2961 if (num_socks == NUM_SOCKS)
2964 if (x11_use_localhost) {
2965 if (num_socks == NUM_SOCKS)
2972 freeaddrinfo(aitop);
2976 if (display_number >= MAX_DISPLAYS) {
2977 error("Failed to allocate internet-domain X11 display socket.");
2980 /* Start listening for connections on the socket. */
2981 for (n = 0; n < num_socks; n++) {
2983 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2984 error("listen: %.100s", strerror(errno));
2990 /* Allocate a channel for each socket. */
2991 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2992 for (n = 0; n < num_socks; n++) {
2995 nc = channel_new("x11 listener",
2996 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2997 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2998 0, "X11 inet listener", 1);
3000 nc = channel_new("x11 listener",
3001 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3002 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
3003 0, "X11 inet listener", 1);
3004 nc->single_connection = single_connection;
3005 (*chanids)[n] = nc->self;
3009 /* Return the display number for the DISPLAY environment variable. */
3010 *display_numberp = display_number;
3015 connect_local_xsocket(u_int dnr)
3018 struct sockaddr_un addr;
3020 sock = socket(AF_UNIX, SOCK_STREAM, 0);
3022 error("socket: %.100s", strerror(errno));
3023 memset(&addr, 0, sizeof(addr));
3024 addr.sun_family = AF_UNIX;
3025 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
3026 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3029 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3034 x11_connect_display(void)
3036 u_int display_number;
3037 const char *display;
3038 char buf[1024], *cp;
3039 struct addrinfo hints, *ai, *aitop;
3040 char strport[NI_MAXSERV];
3041 int gaierr, sock = 0;
3043 /* Try to open a socket for the local X server. */
3044 display = getenv("DISPLAY");
3046 error("DISPLAY not set.");
3050 * Now we decode the value of the DISPLAY variable and make a
3051 * connection to the real X server.
3055 * Check if it is a unix domain socket. Unix domain displays are in
3056 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3058 if (strncmp(display, "unix:", 5) == 0 ||
3059 display[0] == ':') {
3060 /* Connect to the unix domain socket. */
3061 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3062 error("Could not parse display number from DISPLAY: %.100s",
3066 /* Create a socket. */
3067 sock = connect_local_xsocket(display_number);
3071 /* OK, we now have a connection to the display. */
3075 * Connect to an inet socket. The DISPLAY value is supposedly
3076 * hostname:d[.s], where hostname may also be numeric IP address.
3078 strlcpy(buf, display, sizeof(buf));
3079 cp = strchr(buf, ':');
3081 error("Could not find ':' in DISPLAY: %.100s", display);
3085 /* buf now contains the host name. But first we parse the display number. */
3086 if (sscanf(cp + 1, "%u", &display_number) != 1) {
3087 error("Could not parse display number from DISPLAY: %.100s",
3092 /* Look up the host address */
3093 memset(&hints, 0, sizeof(hints));
3094 hints.ai_family = IPv4or6;
3095 hints.ai_socktype = SOCK_STREAM;
3096 snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3097 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3098 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
3101 for (ai = aitop; ai; ai = ai->ai_next) {
3102 /* Create a socket. */
3103 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3105 debug2("socket: %.100s", strerror(errno));
3108 /* Connect it to the display. */
3109 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3110 debug2("connect %.100s port %u: %.100s", buf,
3111 6000 + display_number, strerror(errno));
3118 freeaddrinfo(aitop);
3120 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3129 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
3130 * the remote channel number. We should do whatever we want, and respond
3131 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3136 x11_input_open(int type, u_int32_t seq, void *ctxt)
3139 int remote_id, sock = 0;
3142 debug("Received X11 open request.");
3144 remote_id = packet_get_int();
3146 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3147 remote_host = packet_get_string(NULL);
3149 remote_host = xstrdup("unknown (remote did not supply name)");
3153 /* Obtain a connection to the real X display. */
3154 sock = x11_connect_display();
3156 /* Allocate a channel for this connection. */
3157 c = channel_new("connected x11 socket",
3158 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3160 c->remote_id = remote_id;
3165 /* Send refusal to the remote host. */
3166 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3167 packet_put_int(remote_id);
3169 /* Send a confirmation to the remote host. */
3170 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3171 packet_put_int(remote_id);
3172 packet_put_int(c->self);
3177 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3180 deny_input_open(int type, u_int32_t seq, void *ctxt)
3182 int rchan = packet_get_int();
3185 case SSH_SMSG_AGENT_OPEN:
3186 error("Warning: ssh server tried agent forwarding.");
3188 case SSH_SMSG_X11_OPEN:
3189 error("Warning: ssh server tried X11 forwarding.");
3192 error("deny_input_open: type %d", type);
3195 error("Warning: this is probably a break-in attempt by a malicious server.");
3196 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3197 packet_put_int(rchan);
3202 * Requests forwarding of X11 connections, generates fake authentication
3203 * data, and enables authentication spoofing.
3204 * This should be called in the client only.
3207 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3208 const char *proto, const char *data)
3210 u_int data_len = (u_int) strlen(data) / 2;
3217 if (x11_saved_display == NULL)
3218 x11_saved_display = xstrdup(disp);
3219 else if (strcmp(disp, x11_saved_display) != 0) {
3220 error("x11_request_forwarding_with_spoofing: different "
3221 "$DISPLAY already forwarded");
3225 cp = strchr(disp, ':');
3227 cp = strchr(cp, '.');
3229 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3233 if (x11_saved_proto == NULL) {
3234 /* Save protocol name. */
3235 x11_saved_proto = xstrdup(proto);
3237 * Extract real authentication data and generate fake data
3238 * of the same length.
3240 x11_saved_data = xmalloc(data_len);
3241 x11_fake_data = xmalloc(data_len);
3242 for (i = 0; i < data_len; i++) {
3243 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3244 fatal("x11_request_forwarding: bad "
3245 "authentication data: %.100s", data);
3248 x11_saved_data[i] = value;
3249 x11_fake_data[i] = rnd & 0xff;
3252 x11_saved_data_len = data_len;
3253 x11_fake_data_len = data_len;
3256 /* Convert the fake data into hex. */
3257 new_data = tohex(x11_fake_data, data_len);
3259 /* Send the request packet. */
3261 channel_request_start(client_session_id, "x11-req", 0);
3262 packet_put_char(0); /* XXX bool single connection */
3264 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3266 packet_put_cstring(proto);
3267 packet_put_cstring(new_data);
3268 packet_put_int(screen_number);
3270 packet_write_wait();
3275 /* -- agent forwarding */
3277 /* Sends a message to the server to request authentication fd forwarding. */
3280 auth_request_forwarding(void)
3282 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3284 packet_write_wait();