2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
15 * SSH2 support added by Markus Friedl.
16 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 RCSID("$OpenBSD: channels.c,v 1.232 2006/01/30 12:22:22 reyk Exp $");
56 #include "pathnames.h"
62 * Pointer to an array containing all allocated channels. The array is
63 * dynamically extended as needed.
65 static Channel **channels = NULL;
68 * Size of the channel array. All slots of the array must always be
69 * initialized (at least the type field); unused slots set to NULL
71 static u_int channels_alloc = 0;
74 * Maximum file descriptor value used in any of the channels. This is
75 * updated in channel_new.
77 static int channel_max_fd = 0;
80 /* -- tcp forwarding */
83 * Data structure for storing which hosts are permitted for forward requests.
84 * The local sides of any remote forwards are stored in this array to prevent
85 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
86 * network (which might be behind a firewall).
89 char *host_to_connect; /* Connect to 'host'. */
90 u_short port_to_connect; /* Connect to 'port'. */
91 u_short listen_port; /* Remote side should listen port number. */
94 /* List of all permitted host/port pairs to connect. */
95 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
97 /* Number of permitted host/port pairs in the array. */
98 static int num_permitted_opens = 0;
100 * If this is true, all opens are permitted. This is the case on the server
101 * on which we have to trust the client anyway, and the user could do
102 * anything after logging in anyway.
104 static int all_opens_permitted = 0;
107 /* -- X11 forwarding */
109 /* Maximum number of fake X11 displays to try. */
110 #define MAX_DISPLAYS 1000
112 /* Saved X11 local (client) display. */
113 static char *x11_saved_display = NULL;
115 /* Saved X11 authentication protocol name. */
116 static char *x11_saved_proto = NULL;
118 /* Saved X11 authentication data. This is the real data. */
119 static char *x11_saved_data = NULL;
120 static u_int x11_saved_data_len = 0;
123 * Fake X11 authentication data. This is what the server will be sending us;
124 * we should replace any occurrences of this by the real data.
126 static char *x11_fake_data = NULL;
127 static u_int x11_fake_data_len;
130 /* -- agent forwarding */
134 /* AF_UNSPEC or AF_INET or AF_INET6 */
135 static int IPv4or6 = AF_UNSPEC;
138 static void port_open_helper(Channel *c, char *rtype);
140 /* -- channel core */
143 channel_by_id(int id)
147 if (id < 0 || (u_int)id >= channels_alloc) {
148 logit("channel_by_id: %d: bad id", id);
153 logit("channel_by_id: %d: bad id: channel free", id);
160 * Returns the channel if it is allowed to receive protocol messages.
161 * Private channels, like listening sockets, may not receive messages.
164 channel_lookup(int id)
168 if ((c = channel_by_id(id)) == NULL)
172 case SSH_CHANNEL_X11_OPEN:
173 case SSH_CHANNEL_LARVAL:
174 case SSH_CHANNEL_CONNECTING:
175 case SSH_CHANNEL_DYNAMIC:
176 case SSH_CHANNEL_OPENING:
177 case SSH_CHANNEL_OPEN:
178 case SSH_CHANNEL_INPUT_DRAINING:
179 case SSH_CHANNEL_OUTPUT_DRAINING:
183 logit("Non-public channel %d, type %d.", id, c->type);
188 * Register filedescriptors for a channel, used when allocating a channel or
189 * when the channel consumer/producer is ready, e.g. shell exec'd
193 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
194 int extusage, int nonblock)
196 /* Update the maximum file descriptor value. */
197 channel_max_fd = MAX(channel_max_fd, rfd);
198 channel_max_fd = MAX(channel_max_fd, wfd);
199 channel_max_fd = MAX(channel_max_fd, efd);
201 /* XXX set close-on-exec -markus */
205 c->sock = (rfd == wfd) ? rfd : -1;
206 c->ctl_fd = -1; /* XXX: set elsewhere */
208 c->extended_usage = extusage;
210 /* XXX ugly hack: nonblock is only set by the server */
211 if (nonblock && isatty(c->rfd)) {
212 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
214 if (!isatty(c->wfd)) {
215 error("channel %d: wfd %d is not a tty?",
221 c->wfd_isatty = isatty(c->wfd);
223 /* enable nonblocking mode */
235 * Allocate a new channel object and set its type and socket. This will cause
236 * remote_name to be freed.
240 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
241 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
247 /* Do initial allocation if this is the first call. */
248 if (channels_alloc == 0) {
250 channels = xmalloc(channels_alloc * sizeof(Channel *));
251 for (i = 0; i < channels_alloc; i++)
254 /* Try to find a free slot where to put the new channel. */
255 for (found = -1, i = 0; i < channels_alloc; i++)
256 if (channels[i] == NULL) {
257 /* Found a free slot. */
262 /* There are no free slots. Take last+1 slot and expand the array. */
263 found = channels_alloc;
264 if (channels_alloc > 10000)
265 fatal("channel_new: internal error: channels_alloc %d "
266 "too big.", channels_alloc);
267 channels = xrealloc(channels,
268 (channels_alloc + 10) * sizeof(Channel *));
269 channels_alloc += 10;
270 debug2("channel: expanding %d", channels_alloc);
271 for (i = found; i < channels_alloc; i++)
274 /* Initialize and return new channel. */
275 c = channels[found] = xmalloc(sizeof(Channel));
276 memset(c, 0, sizeof(Channel));
277 buffer_init(&c->input);
278 buffer_init(&c->output);
279 buffer_init(&c->extended);
280 c->ostate = CHAN_OUTPUT_OPEN;
281 c->istate = CHAN_INPUT_OPEN;
283 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
287 c->local_window = window;
288 c->local_window_max = window;
289 c->local_consumed = 0;
290 c->local_maxpacket = maxpack;
292 c->remote_name = xstrdup(remote_name);
293 c->remote_window = 0;
294 c->remote_maxpacket = 0;
296 c->single_connection = 0;
297 c->detach_user = NULL;
300 c->confirm_ctx = NULL;
301 c->input_filter = NULL;
302 c->output_filter = NULL;
303 debug("channel %d: new [%s]", found, remote_name);
308 channel_find_maxfd(void)
314 for (i = 0; i < channels_alloc; i++) {
317 max = MAX(max, c->rfd);
318 max = MAX(max, c->wfd);
319 max = MAX(max, c->efd);
326 channel_close_fd(int *fdp)
328 int ret = 0, fd = *fdp;
333 if (fd == channel_max_fd)
334 channel_max_fd = channel_find_maxfd();
339 /* Close all channel fd/socket. */
342 channel_close_fds(Channel *c)
344 debug3("channel %d: close_fds r %d w %d e %d c %d",
345 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
347 channel_close_fd(&c->sock);
348 channel_close_fd(&c->ctl_fd);
349 channel_close_fd(&c->rfd);
350 channel_close_fd(&c->wfd);
351 channel_close_fd(&c->efd);
354 /* Free the channel and close its fd/socket. */
357 channel_free(Channel *c)
362 for (n = 0, i = 0; i < channels_alloc; i++)
365 debug("channel %d: free: %s, nchannels %u", c->self,
366 c->remote_name ? c->remote_name : "???", n);
368 s = channel_open_message();
369 debug3("channel %d: status: %s", c->self, s);
373 shutdown(c->sock, SHUT_RDWR);
375 shutdown(c->ctl_fd, SHUT_RDWR);
376 channel_close_fds(c);
377 buffer_free(&c->input);
378 buffer_free(&c->output);
379 buffer_free(&c->extended);
380 if (c->remote_name) {
381 xfree(c->remote_name);
382 c->remote_name = NULL;
384 channels[c->self] = NULL;
389 channel_free_all(void)
393 for (i = 0; i < channels_alloc; i++)
394 if (channels[i] != NULL)
395 channel_free(channels[i]);
399 * Closes the sockets/fds of all channels. This is used to close extra file
400 * descriptors after a fork.
404 channel_close_all(void)
408 for (i = 0; i < channels_alloc; i++)
409 if (channels[i] != NULL)
410 channel_close_fds(channels[i]);
414 * Stop listening to channels.
418 channel_stop_listening(void)
423 for (i = 0; i < channels_alloc; i++) {
427 case SSH_CHANNEL_AUTH_SOCKET:
428 case SSH_CHANNEL_PORT_LISTENER:
429 case SSH_CHANNEL_RPORT_LISTENER:
430 case SSH_CHANNEL_X11_LISTENER:
431 channel_close_fd(&c->sock);
440 * Returns true if no channel has too much buffered data, and false if one or
441 * more channel is overfull.
445 channel_not_very_much_buffered_data(void)
450 for (i = 0; i < channels_alloc; i++) {
452 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
455 buffer_len(&c->input) > packet_get_maxsize()) {
456 debug2("channel %d: big input buffer %d",
457 c->self, buffer_len(&c->input));
461 if (buffer_len(&c->output) > packet_get_maxsize()) {
462 debug2("channel %d: big output buffer %u > %u",
463 c->self, buffer_len(&c->output),
464 packet_get_maxsize());
472 /* Returns true if any channel is still open. */
475 channel_still_open(void)
480 for (i = 0; i < channels_alloc; i++) {
485 case SSH_CHANNEL_X11_LISTENER:
486 case SSH_CHANNEL_PORT_LISTENER:
487 case SSH_CHANNEL_RPORT_LISTENER:
488 case SSH_CHANNEL_CLOSED:
489 case SSH_CHANNEL_AUTH_SOCKET:
490 case SSH_CHANNEL_DYNAMIC:
491 case SSH_CHANNEL_CONNECTING:
492 case SSH_CHANNEL_ZOMBIE:
494 case SSH_CHANNEL_LARVAL:
496 fatal("cannot happen: SSH_CHANNEL_LARVAL");
498 case SSH_CHANNEL_OPENING:
499 case SSH_CHANNEL_OPEN:
500 case SSH_CHANNEL_X11_OPEN:
502 case SSH_CHANNEL_INPUT_DRAINING:
503 case SSH_CHANNEL_OUTPUT_DRAINING:
505 fatal("cannot happen: OUT_DRAIN");
508 fatal("channel_still_open: bad channel type %d", c->type);
515 /* Returns the id of an open channel suitable for keepaliving */
518 channel_find_open(void)
523 for (i = 0; i < channels_alloc; i++) {
525 if (c == NULL || c->remote_id < 0)
528 case SSH_CHANNEL_CLOSED:
529 case SSH_CHANNEL_DYNAMIC:
530 case SSH_CHANNEL_X11_LISTENER:
531 case SSH_CHANNEL_PORT_LISTENER:
532 case SSH_CHANNEL_RPORT_LISTENER:
533 case SSH_CHANNEL_OPENING:
534 case SSH_CHANNEL_CONNECTING:
535 case SSH_CHANNEL_ZOMBIE:
537 case SSH_CHANNEL_LARVAL:
538 case SSH_CHANNEL_AUTH_SOCKET:
539 case SSH_CHANNEL_OPEN:
540 case SSH_CHANNEL_X11_OPEN:
542 case SSH_CHANNEL_INPUT_DRAINING:
543 case SSH_CHANNEL_OUTPUT_DRAINING:
545 fatal("cannot happen: OUT_DRAIN");
548 fatal("channel_find_open: bad channel type %d", c->type);
557 * Returns a message describing the currently open forwarded connections,
558 * suitable for sending to the client. The message contains crlf pairs for
563 channel_open_message(void)
570 buffer_init(&buffer);
571 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
572 buffer_append(&buffer, buf, strlen(buf));
573 for (i = 0; i < channels_alloc; i++) {
578 case SSH_CHANNEL_X11_LISTENER:
579 case SSH_CHANNEL_PORT_LISTENER:
580 case SSH_CHANNEL_RPORT_LISTENER:
581 case SSH_CHANNEL_CLOSED:
582 case SSH_CHANNEL_AUTH_SOCKET:
583 case SSH_CHANNEL_ZOMBIE:
585 case SSH_CHANNEL_LARVAL:
586 case SSH_CHANNEL_OPENING:
587 case SSH_CHANNEL_CONNECTING:
588 case SSH_CHANNEL_DYNAMIC:
589 case SSH_CHANNEL_OPEN:
590 case SSH_CHANNEL_X11_OPEN:
591 case SSH_CHANNEL_INPUT_DRAINING:
592 case SSH_CHANNEL_OUTPUT_DRAINING:
593 snprintf(buf, sizeof buf,
594 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
595 c->self, c->remote_name,
596 c->type, c->remote_id,
597 c->istate, buffer_len(&c->input),
598 c->ostate, buffer_len(&c->output),
599 c->rfd, c->wfd, c->ctl_fd);
600 buffer_append(&buffer, buf, strlen(buf));
603 fatal("channel_open_message: bad channel type %d", c->type);
607 buffer_append(&buffer, "\0", 1);
608 cp = xstrdup(buffer_ptr(&buffer));
609 buffer_free(&buffer);
614 channel_send_open(int id)
616 Channel *c = channel_lookup(id);
619 logit("channel_send_open: %d: bad id", id);
622 debug2("channel %d: send open", id);
623 packet_start(SSH2_MSG_CHANNEL_OPEN);
624 packet_put_cstring(c->ctype);
625 packet_put_int(c->self);
626 packet_put_int(c->local_window);
627 packet_put_int(c->local_maxpacket);
632 channel_request_start(int id, char *service, int wantconfirm)
634 Channel *c = channel_lookup(id);
637 logit("channel_request_start: %d: unknown channel id", id);
640 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
641 packet_start(SSH2_MSG_CHANNEL_REQUEST);
642 packet_put_int(c->remote_id);
643 packet_put_cstring(service);
644 packet_put_char(wantconfirm);
647 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
649 Channel *c = channel_lookup(id);
652 logit("channel_register_comfirm: %d: bad id", id);
656 c->confirm_ctx = ctx;
659 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
661 Channel *c = channel_by_id(id);
664 logit("channel_register_cleanup: %d: bad id", id);
668 c->detach_close = do_close;
671 channel_cancel_cleanup(int id)
673 Channel *c = channel_by_id(id);
676 logit("channel_cancel_cleanup: %d: bad id", id);
679 c->detach_user = NULL;
683 channel_register_filter(int id, channel_infilter_fn *ifn,
684 channel_outfilter_fn *ofn)
686 Channel *c = channel_lookup(id);
689 logit("channel_register_filter: %d: bad id", id);
692 c->input_filter = ifn;
693 c->output_filter = ofn;
697 channel_set_fds(int id, int rfd, int wfd, int efd,
698 int extusage, int nonblock, u_int window_max)
700 Channel *c = channel_lookup(id);
702 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
703 fatal("channel_activate for non-larval channel %d.", id);
704 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
705 c->type = SSH_CHANNEL_OPEN;
706 c->local_window = c->local_window_max = window_max;
707 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
708 packet_put_int(c->remote_id);
709 packet_put_int(c->local_window);
714 * 'channel_pre*' are called just before select() to add any bits relevant to
715 * channels in the select bitmasks.
718 * 'channel_post*': perform any appropriate operations for channels which
719 * have events pending.
721 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
722 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
723 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
726 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
728 FD_SET(c->sock, readset);
732 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
734 debug3("channel %d: waiting for connection", c->self);
735 FD_SET(c->sock, writeset);
739 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
741 if (buffer_len(&c->input) < packet_get_maxsize())
742 FD_SET(c->sock, readset);
743 if (buffer_len(&c->output) > 0)
744 FD_SET(c->sock, writeset);
748 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
750 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
752 /* check buffer limits */
753 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
755 if (c->istate == CHAN_INPUT_OPEN &&
757 buffer_len(&c->input) < limit)
758 FD_SET(c->rfd, readset);
759 if (c->ostate == CHAN_OUTPUT_OPEN ||
760 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
761 if (buffer_len(&c->output) > 0) {
762 FD_SET(c->wfd, writeset);
763 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
764 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
765 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
766 c->self, c->efd, buffer_len(&c->extended));
771 /** XXX check close conditions, too */
772 if (compat20 && c->efd != -1) {
773 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
774 buffer_len(&c->extended) > 0)
775 FD_SET(c->efd, writeset);
776 else if (!(c->flags & CHAN_EOF_SENT) &&
777 c->extended_usage == CHAN_EXTENDED_READ &&
778 buffer_len(&c->extended) < c->remote_window)
779 FD_SET(c->efd, readset);
781 /* XXX: What about efd? races? */
782 if (compat20 && c->ctl_fd != -1 &&
783 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
784 FD_SET(c->ctl_fd, readset);
788 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
790 if (buffer_len(&c->input) == 0) {
791 packet_start(SSH_MSG_CHANNEL_CLOSE);
792 packet_put_int(c->remote_id);
794 c->type = SSH_CHANNEL_CLOSED;
795 debug2("channel %d: closing after input drain.", c->self);
800 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
802 if (buffer_len(&c->output) == 0)
805 FD_SET(c->sock, writeset);
809 * This is a special state for X11 authentication spoofing. An opened X11
810 * connection (when authentication spoofing is being done) remains in this
811 * state until the first packet has been completely read. The authentication
812 * data in that packet is then substituted by the real data if it matches the
813 * fake data, and the channel is put into normal mode.
814 * XXX All this happens at the client side.
815 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
818 x11_open_helper(Buffer *b)
821 u_int proto_len, data_len;
823 /* Check if the fixed size part of the packet is in buffer. */
824 if (buffer_len(b) < 12)
827 /* Parse the lengths of variable-length fields. */
829 if (ucp[0] == 0x42) { /* Byte order MSB first. */
830 proto_len = 256 * ucp[6] + ucp[7];
831 data_len = 256 * ucp[8] + ucp[9];
832 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
833 proto_len = ucp[6] + 256 * ucp[7];
834 data_len = ucp[8] + 256 * ucp[9];
836 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
841 /* Check if the whole packet is in buffer. */
843 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
846 /* Check if authentication protocol matches. */
847 if (proto_len != strlen(x11_saved_proto) ||
848 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
849 debug2("X11 connection uses different authentication protocol.");
852 /* Check if authentication data matches our fake data. */
853 if (data_len != x11_fake_data_len ||
854 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
855 x11_fake_data, x11_fake_data_len) != 0) {
856 debug2("X11 auth data does not match fake data.");
859 /* Check fake data length */
860 if (x11_fake_data_len != x11_saved_data_len) {
861 error("X11 fake_data_len %d != saved_data_len %d",
862 x11_fake_data_len, x11_saved_data_len);
866 * Received authentication protocol and data match
867 * our fake data. Substitute the fake data with real
870 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
871 x11_saved_data, x11_saved_data_len);
876 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
878 int ret = x11_open_helper(&c->output);
881 /* Start normal processing for the channel. */
882 c->type = SSH_CHANNEL_OPEN;
883 channel_pre_open_13(c, readset, writeset);
884 } else if (ret == -1) {
886 * We have received an X11 connection that has bad
887 * authentication information.
889 logit("X11 connection rejected because of wrong authentication.");
890 buffer_clear(&c->input);
891 buffer_clear(&c->output);
892 channel_close_fd(&c->sock);
894 c->type = SSH_CHANNEL_CLOSED;
895 packet_start(SSH_MSG_CHANNEL_CLOSE);
896 packet_put_int(c->remote_id);
902 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
904 int ret = x11_open_helper(&c->output);
906 /* c->force_drain = 1; */
909 c->type = SSH_CHANNEL_OPEN;
910 channel_pre_open(c, readset, writeset);
911 } else if (ret == -1) {
912 logit("X11 connection rejected because of wrong authentication.");
913 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
915 buffer_clear(&c->input);
917 buffer_clear(&c->output);
918 /* for proto v1, the peer will send an IEOF */
920 chan_write_failed(c);
922 c->type = SSH_CHANNEL_OPEN;
923 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
927 /* try to decode a socks4 header */
929 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
932 u_int len, have, i, found;
938 struct in_addr dest_addr;
941 debug2("channel %d: decode socks4", c->self);
943 have = buffer_len(&c->input);
944 len = sizeof(s4_req);
947 p = buffer_ptr(&c->input);
948 for (found = 0, i = len; i < have; i++) {
954 /* the peer is probably sending garbage */
955 debug("channel %d: decode socks4: too long",
962 buffer_get(&c->input, (char *)&s4_req.version, 1);
963 buffer_get(&c->input, (char *)&s4_req.command, 1);
964 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
965 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
966 have = buffer_len(&c->input);
967 p = buffer_ptr(&c->input);
969 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
971 fatal("channel %d: decode socks4: len %d > have %d",
973 strlcpy(username, p, sizeof(username));
974 buffer_consume(&c->input, len);
975 buffer_consume(&c->input, 1); /* trailing '\0' */
977 host = inet_ntoa(s4_req.dest_addr);
978 strlcpy(c->path, host, sizeof(c->path));
979 c->host_port = ntohs(s4_req.dest_port);
981 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
982 c->self, host, c->host_port, s4_req.command);
984 if (s4_req.command != 1) {
985 debug("channel %d: cannot handle: socks4 cn %d",
986 c->self, s4_req.command);
989 s4_rsp.version = 0; /* vn: 0 for reply */
990 s4_rsp.command = 90; /* cd: req granted */
991 s4_rsp.dest_port = 0; /* ignored */
992 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
993 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
997 /* try to decode a socks5 header */
998 #define SSH_SOCKS5_AUTHDONE 0x1000
999 #define SSH_SOCKS5_NOAUTH 0x00
1000 #define SSH_SOCKS5_IPV4 0x01
1001 #define SSH_SOCKS5_DOMAIN 0x03
1002 #define SSH_SOCKS5_IPV6 0x04
1003 #define SSH_SOCKS5_CONNECT 0x01
1004 #define SSH_SOCKS5_SUCCESS 0x00
1007 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
1015 u_int16_t dest_port;
1016 u_char *p, dest_addr[255+1];
1017 u_int have, i, found, nmethods, addrlen, af;
1019 debug2("channel %d: decode socks5", c->self);
1020 p = buffer_ptr(&c->input);
1023 have = buffer_len(&c->input);
1024 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1025 /* format: ver | nmethods | methods */
1029 if (have < nmethods + 2)
1031 /* look for method: "NO AUTHENTICATION REQUIRED" */
1032 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1033 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1039 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1043 buffer_consume(&c->input, nmethods + 2);
1044 buffer_put_char(&c->output, 0x05); /* version */
1045 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1046 FD_SET(c->sock, writeset);
1047 c->flags |= SSH_SOCKS5_AUTHDONE;
1048 debug2("channel %d: socks5 auth done", c->self);
1049 return 0; /* need more */
1051 debug2("channel %d: socks5 post auth", c->self);
1052 if (have < sizeof(s5_req)+1)
1053 return 0; /* need more */
1054 memcpy((char *)&s5_req, p, sizeof(s5_req));
1055 if (s5_req.version != 0x05 ||
1056 s5_req.command != SSH_SOCKS5_CONNECT ||
1057 s5_req.reserved != 0x00) {
1058 debug2("channel %d: only socks5 connect supported", c->self);
1061 switch (s5_req.atyp){
1062 case SSH_SOCKS5_IPV4:
1066 case SSH_SOCKS5_DOMAIN:
1067 addrlen = p[sizeof(s5_req)];
1070 case SSH_SOCKS5_IPV6:
1075 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1078 if (have < 4 + addrlen + 2)
1080 buffer_consume(&c->input, sizeof(s5_req));
1081 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1082 buffer_consume(&c->input, 1); /* host string length */
1083 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1084 buffer_get(&c->input, (char *)&dest_port, 2);
1085 dest_addr[addrlen] = '\0';
1086 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1087 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1088 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1090 c->host_port = ntohs(dest_port);
1092 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1093 c->self, c->path, c->host_port, s5_req.command);
1095 s5_rsp.version = 0x05;
1096 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1097 s5_rsp.reserved = 0; /* ignored */
1098 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1099 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1100 dest_port = 0; /* ignored */
1102 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1103 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1104 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1108 /* dynamic port forwarding */
1110 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1116 have = buffer_len(&c->input);
1118 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1119 /* buffer_dump(&c->input); */
1120 /* check if the fixed size part of the packet is in buffer. */
1123 FD_SET(c->sock, readset);
1126 /* try to guess the protocol */
1127 p = buffer_ptr(&c->input);
1130 ret = channel_decode_socks4(c, readset, writeset);
1133 ret = channel_decode_socks5(c, readset, writeset);
1141 } else if (ret == 0) {
1142 debug2("channel %d: pre_dynamic: need more", c->self);
1144 FD_SET(c->sock, readset);
1146 /* switch to the next state */
1147 c->type = SSH_CHANNEL_OPENING;
1148 port_open_helper(c, "direct-tcpip");
1152 /* This is our fake X11 server socket. */
1154 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1157 struct sockaddr addr;
1160 char buf[16384], *remote_ipaddr;
1163 if (FD_ISSET(c->sock, readset)) {
1164 debug("X11 connection requested.");
1165 addrlen = sizeof(addr);
1166 newsock = accept(c->sock, &addr, &addrlen);
1167 if (c->single_connection) {
1168 debug2("single_connection: closing X11 listener.");
1169 channel_close_fd(&c->sock);
1173 error("accept: %.100s", strerror(errno));
1176 set_nodelay(newsock);
1177 remote_ipaddr = get_peer_ipaddr(newsock);
1178 remote_port = get_peer_port(newsock);
1179 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1180 remote_ipaddr, remote_port);
1182 nc = channel_new("accepted x11 socket",
1183 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1184 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1186 packet_start(SSH2_MSG_CHANNEL_OPEN);
1187 packet_put_cstring("x11");
1188 packet_put_int(nc->self);
1189 packet_put_int(nc->local_window_max);
1190 packet_put_int(nc->local_maxpacket);
1191 /* originator ipaddr and port */
1192 packet_put_cstring(remote_ipaddr);
1193 if (datafellows & SSH_BUG_X11FWD) {
1194 debug2("ssh2 x11 bug compat mode");
1196 packet_put_int(remote_port);
1200 packet_start(SSH_SMSG_X11_OPEN);
1201 packet_put_int(nc->self);
1202 if (packet_get_protocol_flags() &
1203 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1204 packet_put_cstring(buf);
1207 xfree(remote_ipaddr);
1212 port_open_helper(Channel *c, char *rtype)
1216 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1217 int remote_port = get_peer_port(c->sock);
1219 direct = (strcmp(rtype, "direct-tcpip") == 0);
1221 snprintf(buf, sizeof buf,
1222 "%s: listening port %d for %.100s port %d, "
1223 "connect from %.200s port %d",
1224 rtype, c->listening_port, c->path, c->host_port,
1225 remote_ipaddr, remote_port);
1227 xfree(c->remote_name);
1228 c->remote_name = xstrdup(buf);
1231 packet_start(SSH2_MSG_CHANNEL_OPEN);
1232 packet_put_cstring(rtype);
1233 packet_put_int(c->self);
1234 packet_put_int(c->local_window_max);
1235 packet_put_int(c->local_maxpacket);
1237 /* target host, port */
1238 packet_put_cstring(c->path);
1239 packet_put_int(c->host_port);
1241 /* listen address, port */
1242 packet_put_cstring(c->path);
1243 packet_put_int(c->listening_port);
1245 /* originator host and port */
1246 packet_put_cstring(remote_ipaddr);
1247 packet_put_int((u_int)remote_port);
1250 packet_start(SSH_MSG_PORT_OPEN);
1251 packet_put_int(c->self);
1252 packet_put_cstring(c->path);
1253 packet_put_int(c->host_port);
1254 if (packet_get_protocol_flags() &
1255 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1256 packet_put_cstring(c->remote_name);
1259 xfree(remote_ipaddr);
1263 channel_set_reuseaddr(int fd)
1268 * Set socket options.
1269 * Allow local port reuse in TIME_WAIT.
1271 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1272 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1276 * This socket is listening for connections to a forwarded TCP/IP port.
1279 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1282 struct sockaddr addr;
1283 int newsock, nextstate;
1287 if (FD_ISSET(c->sock, readset)) {
1288 debug("Connection to port %d forwarding "
1289 "to %.100s port %d requested.",
1290 c->listening_port, c->path, c->host_port);
1292 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1293 nextstate = SSH_CHANNEL_OPENING;
1294 rtype = "forwarded-tcpip";
1296 if (c->host_port == 0) {
1297 nextstate = SSH_CHANNEL_DYNAMIC;
1298 rtype = "dynamic-tcpip";
1300 nextstate = SSH_CHANNEL_OPENING;
1301 rtype = "direct-tcpip";
1305 addrlen = sizeof(addr);
1306 newsock = accept(c->sock, &addr, &addrlen);
1308 error("accept: %.100s", strerror(errno));
1311 set_nodelay(newsock);
1312 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1313 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1314 nc->listening_port = c->listening_port;
1315 nc->host_port = c->host_port;
1316 strlcpy(nc->path, c->path, sizeof(nc->path));
1318 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1320 * do not call the channel_post handler until
1321 * this flag has been reset by a pre-handler.
1322 * otherwise the FD_ISSET calls might overflow
1326 port_open_helper(nc, rtype);
1332 * This is the authentication agent socket listening for connections from
1336 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1340 struct sockaddr addr;
1343 if (FD_ISSET(c->sock, readset)) {
1344 addrlen = sizeof(addr);
1345 newsock = accept(c->sock, &addr, &addrlen);
1347 error("accept from auth socket: %.100s", strerror(errno));
1350 nc = channel_new("accepted auth socket",
1351 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1352 c->local_window_max, c->local_maxpacket,
1353 0, "accepted auth socket", 1);
1355 packet_start(SSH2_MSG_CHANNEL_OPEN);
1356 packet_put_cstring("auth-agent@openssh.com");
1357 packet_put_int(nc->self);
1358 packet_put_int(c->local_window_max);
1359 packet_put_int(c->local_maxpacket);
1361 packet_start(SSH_SMSG_AGENT_OPEN);
1362 packet_put_int(nc->self);
1369 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1372 socklen_t sz = sizeof(err);
1374 if (FD_ISSET(c->sock, writeset)) {
1375 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1377 error("getsockopt SO_ERROR failed");
1380 debug("channel %d: connected", c->self);
1381 c->type = SSH_CHANNEL_OPEN;
1383 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1384 packet_put_int(c->remote_id);
1385 packet_put_int(c->self);
1386 packet_put_int(c->local_window);
1387 packet_put_int(c->local_maxpacket);
1389 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1390 packet_put_int(c->remote_id);
1391 packet_put_int(c->self);
1394 debug("channel %d: not connected: %s",
1395 c->self, strerror(err));
1397 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1398 packet_put_int(c->remote_id);
1399 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1400 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1401 packet_put_cstring(strerror(err));
1402 packet_put_cstring("");
1405 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1406 packet_put_int(c->remote_id);
1415 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1417 char buf[CHAN_RBUF];
1421 FD_ISSET(c->rfd, readset)) {
1422 len = read(c->rfd, buf, sizeof(buf));
1423 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1426 debug2("channel %d: read<=0 rfd %d len %d",
1427 c->self, c->rfd, len);
1428 if (c->type != SSH_CHANNEL_OPEN) {
1429 debug2("channel %d: not open", c->self);
1432 } else if (compat13) {
1433 buffer_clear(&c->output);
1434 c->type = SSH_CHANNEL_INPUT_DRAINING;
1435 debug2("channel %d: input draining.", c->self);
1437 chan_read_failed(c);
1441 if (c->input_filter != NULL) {
1442 if (c->input_filter(c, buf, len) == -1) {
1443 debug2("channel %d: filter stops", c->self);
1444 chan_read_failed(c);
1446 } else if (c->datagram) {
1447 buffer_put_string(&c->input, buf, len);
1449 buffer_append(&c->input, buf, len);
1455 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1458 u_char *data = NULL, *buf;
1462 /* Send buffered output data to the socket. */
1464 FD_ISSET(c->wfd, writeset) &&
1465 buffer_len(&c->output) > 0) {
1466 if (c->output_filter != NULL) {
1467 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1468 debug2("channel %d: filter stops", c->self);
1469 if (c->type != SSH_CHANNEL_OPEN)
1472 chan_write_failed(c);
1475 } else if (c->datagram) {
1476 buf = data = buffer_get_string(&c->output, &dlen);
1478 buf = data = buffer_ptr(&c->output);
1479 dlen = buffer_len(&c->output);
1483 /* ignore truncated writes, datagrams might get lost */
1484 c->local_consumed += dlen + 4;
1485 len = write(c->wfd, buf, dlen);
1487 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1490 if (c->type != SSH_CHANNEL_OPEN)
1493 chan_write_failed(c);
1499 /* XXX: Later AIX versions can't push as much data to tty */
1500 if (compat20 && c->wfd_isatty)
1501 dlen = MIN(dlen, 8*1024);
1504 len = write(c->wfd, buf, dlen);
1505 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1508 if (c->type != SSH_CHANNEL_OPEN) {
1509 debug2("channel %d: not open", c->self);
1512 } else if (compat13) {
1513 buffer_clear(&c->output);
1514 debug2("channel %d: input draining.", c->self);
1515 c->type = SSH_CHANNEL_INPUT_DRAINING;
1517 chan_write_failed(c);
1521 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1522 if (tcgetattr(c->wfd, &tio) == 0 &&
1523 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1525 * Simulate echo to reduce the impact of
1526 * traffic analysis. We need to match the
1527 * size of a SSH2_MSG_CHANNEL_DATA message
1528 * (4 byte channel id + buf)
1530 packet_send_ignore(4 + len);
1534 buffer_consume(&c->output, len);
1535 if (compat20 && len > 0) {
1536 c->local_consumed += len;
1542 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1544 char buf[CHAN_RBUF];
1547 /** XXX handle drain efd, too */
1549 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1550 FD_ISSET(c->efd, writeset) &&
1551 buffer_len(&c->extended) > 0) {
1552 len = write(c->efd, buffer_ptr(&c->extended),
1553 buffer_len(&c->extended));
1554 debug2("channel %d: written %d to efd %d",
1555 c->self, len, c->efd);
1556 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1559 debug2("channel %d: closing write-efd %d",
1561 channel_close_fd(&c->efd);
1563 buffer_consume(&c->extended, len);
1564 c->local_consumed += len;
1566 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1567 FD_ISSET(c->efd, readset)) {
1568 len = read(c->efd, buf, sizeof(buf));
1569 debug2("channel %d: read %d from efd %d",
1570 c->self, len, c->efd);
1571 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1574 debug2("channel %d: closing read-efd %d",
1576 channel_close_fd(&c->efd);
1578 buffer_append(&c->extended, buf, len);
1585 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1590 /* Monitor control fd to detect if the slave client exits */
1591 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1592 len = read(c->ctl_fd, buf, sizeof(buf));
1593 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1596 debug2("channel %d: ctl read<=0", c->self);
1597 if (c->type != SSH_CHANNEL_OPEN) {
1598 debug2("channel %d: not open", c->self);
1602 chan_read_failed(c);
1603 chan_write_failed(c);
1607 fatal("%s: unexpected data on ctl fd", __func__);
1612 channel_check_window(Channel *c)
1614 if (c->type == SSH_CHANNEL_OPEN &&
1615 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1616 c->local_window < c->local_window_max/2 &&
1617 c->local_consumed > 0) {
1618 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1619 packet_put_int(c->remote_id);
1620 packet_put_int(c->local_consumed);
1622 debug2("channel %d: window %d sent adjust %d",
1623 c->self, c->local_window,
1625 c->local_window += c->local_consumed;
1626 c->local_consumed = 0;
1632 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1636 channel_handle_rfd(c, readset, writeset);
1637 channel_handle_wfd(c, readset, writeset);
1640 channel_handle_efd(c, readset, writeset);
1641 channel_handle_ctl(c, readset, writeset);
1642 channel_check_window(c);
1646 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1650 /* Send buffered output data to the socket. */
1651 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1652 len = write(c->sock, buffer_ptr(&c->output),
1653 buffer_len(&c->output));
1655 buffer_clear(&c->output);
1657 buffer_consume(&c->output, len);
1662 channel_handler_init_20(void)
1664 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1665 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1666 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1667 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1668 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1669 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1670 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1671 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1673 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1674 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1675 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1676 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1677 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1678 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1679 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1683 channel_handler_init_13(void)
1685 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1686 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1687 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1688 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1689 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1690 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1691 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1692 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1693 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1695 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1696 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1697 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1698 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1699 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1700 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1701 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1705 channel_handler_init_15(void)
1707 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1708 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1709 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1710 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1711 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1712 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1713 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1715 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1716 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1717 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1718 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1719 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1720 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1724 channel_handler_init(void)
1728 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1729 channel_pre[i] = NULL;
1730 channel_post[i] = NULL;
1733 channel_handler_init_20();
1735 channel_handler_init_13();
1737 channel_handler_init_15();
1740 /* gc dead channels */
1742 channel_garbage_collect(Channel *c)
1746 if (c->detach_user != NULL) {
1747 if (!chan_is_dead(c, c->detach_close))
1749 debug2("channel %d: gc: notify user", c->self);
1750 c->detach_user(c->self, NULL);
1751 /* if we still have a callback */
1752 if (c->detach_user != NULL)
1754 debug2("channel %d: gc: user detached", c->self);
1756 if (!chan_is_dead(c, 1))
1758 debug2("channel %d: garbage collecting", c->self);
1763 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1765 static int did_init = 0;
1770 channel_handler_init();
1773 for (i = 0; i < channels_alloc; i++) {
1777 if (ftab[c->type] != NULL)
1778 (*ftab[c->type])(c, readset, writeset);
1779 channel_garbage_collect(c);
1784 * Allocate/update select bitmasks and add any bits relevant to channels in
1788 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1789 u_int *nallocp, int rekeying)
1793 n = MAX(*maxfdp, channel_max_fd);
1795 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1796 /* perhaps check sz < nalloc/2 and shrink? */
1797 if (*readsetp == NULL || sz > *nallocp) {
1798 *readsetp = xrealloc(*readsetp, sz);
1799 *writesetp = xrealloc(*writesetp, sz);
1803 memset(*readsetp, 0, sz);
1804 memset(*writesetp, 0, sz);
1807 channel_handler(channel_pre, *readsetp, *writesetp);
1811 * After select, perform any appropriate operations for channels which have
1815 channel_after_select(fd_set * readset, fd_set * writeset)
1817 channel_handler(channel_post, readset, writeset);
1821 /* If there is data to send to the connection, enqueue some of it now. */
1824 channel_output_poll(void)
1829 for (i = 0; i < channels_alloc; i++) {
1835 * We are only interested in channels that can have buffered
1839 if (c->type != SSH_CHANNEL_OPEN &&
1840 c->type != SSH_CHANNEL_INPUT_DRAINING)
1843 if (c->type != SSH_CHANNEL_OPEN)
1847 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1848 /* XXX is this true? */
1849 debug3("channel %d: will not send data after close", c->self);
1853 /* Get the amount of buffered data for this channel. */
1854 if ((c->istate == CHAN_INPUT_OPEN ||
1855 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1856 (len = buffer_len(&c->input)) > 0) {
1862 data = buffer_get_string(&c->input,
1864 packet_start(SSH2_MSG_CHANNEL_DATA);
1865 packet_put_int(c->remote_id);
1866 packet_put_string(data, dlen);
1868 c->remote_window -= dlen + 4;
1874 * Send some data for the other side over the secure
1878 if (len > c->remote_window)
1879 len = c->remote_window;
1880 if (len > c->remote_maxpacket)
1881 len = c->remote_maxpacket;
1883 if (packet_is_interactive()) {
1887 /* Keep the packets at reasonable size. */
1888 if (len > packet_get_maxsize()/2)
1889 len = packet_get_maxsize()/2;
1893 packet_start(compat20 ?
1894 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1895 packet_put_int(c->remote_id);
1896 packet_put_string(buffer_ptr(&c->input), len);
1898 buffer_consume(&c->input, len);
1899 c->remote_window -= len;
1901 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1903 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1905 * input-buffer is empty and read-socket shutdown:
1906 * tell peer, that we will not send more data: send IEOF.
1907 * hack for extended data: delay EOF if EFD still in use.
1909 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1910 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1911 c->self, c->efd, buffer_len(&c->extended));
1915 /* Send extended data, i.e. stderr */
1917 !(c->flags & CHAN_EOF_SENT) &&
1918 c->remote_window > 0 &&
1919 (len = buffer_len(&c->extended)) > 0 &&
1920 c->extended_usage == CHAN_EXTENDED_READ) {
1921 debug2("channel %d: rwin %u elen %u euse %d",
1922 c->self, c->remote_window, buffer_len(&c->extended),
1924 if (len > c->remote_window)
1925 len = c->remote_window;
1926 if (len > c->remote_maxpacket)
1927 len = c->remote_maxpacket;
1928 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1929 packet_put_int(c->remote_id);
1930 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1931 packet_put_string(buffer_ptr(&c->extended), len);
1933 buffer_consume(&c->extended, len);
1934 c->remote_window -= len;
1935 debug2("channel %d: sent ext data %d", c->self, len);
1941 /* -- protocol input */
1944 channel_input_data(int type, u_int32_t seq, void *ctxt)
1951 /* Get the channel number and verify it. */
1952 id = packet_get_int();
1953 c = channel_lookup(id);
1955 packet_disconnect("Received data for nonexistent channel %d.", id);
1957 /* Ignore any data for non-open channels (might happen on close) */
1958 if (c->type != SSH_CHANNEL_OPEN &&
1959 c->type != SSH_CHANNEL_X11_OPEN)
1963 data = packet_get_string(&data_len);
1966 * Ignore data for protocol > 1.3 if output end is no longer open.
1967 * For protocol 2 the sending side is reducing its window as it sends
1968 * data, so we must 'fake' consumption of the data in order to ensure
1969 * that window updates are sent back. Otherwise the connection might
1972 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1974 c->local_window -= data_len;
1975 c->local_consumed += data_len;
1982 if (data_len > c->local_maxpacket) {
1983 logit("channel %d: rcvd big packet %d, maxpack %d",
1984 c->self, data_len, c->local_maxpacket);
1986 if (data_len > c->local_window) {
1987 logit("channel %d: rcvd too much data %d, win %d",
1988 c->self, data_len, c->local_window);
1992 c->local_window -= data_len;
1996 buffer_put_string(&c->output, data, data_len);
1998 buffer_append(&c->output, data, data_len);
2003 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2007 u_int data_len, tcode;
2010 /* Get the channel number and verify it. */
2011 id = packet_get_int();
2012 c = channel_lookup(id);
2015 packet_disconnect("Received extended_data for bad channel %d.", id);
2016 if (c->type != SSH_CHANNEL_OPEN) {
2017 logit("channel %d: ext data for non open", id);
2020 if (c->flags & CHAN_EOF_RCVD) {
2021 if (datafellows & SSH_BUG_EXTEOF)
2022 debug("channel %d: accepting ext data after eof", id);
2024 packet_disconnect("Received extended_data after EOF "
2025 "on channel %d.", id);
2027 tcode = packet_get_int();
2029 c->extended_usage != CHAN_EXTENDED_WRITE ||
2030 tcode != SSH2_EXTENDED_DATA_STDERR) {
2031 logit("channel %d: bad ext data", c->self);
2034 data = packet_get_string(&data_len);
2036 if (data_len > c->local_window) {
2037 logit("channel %d: rcvd too much extended_data %d, win %d",
2038 c->self, data_len, c->local_window);
2042 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2043 c->local_window -= data_len;
2044 buffer_append(&c->extended, data, data_len);
2049 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2054 id = packet_get_int();
2056 c = channel_lookup(id);
2058 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2061 /* XXX force input close */
2062 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2063 debug("channel %d: FORCE input drain", c->self);
2064 c->istate = CHAN_INPUT_WAIT_DRAIN;
2065 if (buffer_len(&c->input) == 0)
2072 channel_input_close(int type, u_int32_t seq, void *ctxt)
2077 id = packet_get_int();
2079 c = channel_lookup(id);
2081 packet_disconnect("Received close for nonexistent channel %d.", id);
2084 * Send a confirmation that we have closed the channel and no more
2085 * data is coming for it.
2087 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2088 packet_put_int(c->remote_id);
2092 * If the channel is in closed state, we have sent a close request,
2093 * and the other side will eventually respond with a confirmation.
2094 * Thus, we cannot free the channel here, because then there would be
2095 * no-one to receive the confirmation. The channel gets freed when
2096 * the confirmation arrives.
2098 if (c->type != SSH_CHANNEL_CLOSED) {
2100 * Not a closed channel - mark it as draining, which will
2101 * cause it to be freed later.
2103 buffer_clear(&c->input);
2104 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2108 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2110 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2112 int id = packet_get_int();
2113 Channel *c = channel_lookup(id);
2117 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2118 chan_rcvd_oclose(c);
2122 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2124 int id = packet_get_int();
2125 Channel *c = channel_lookup(id);
2129 packet_disconnect("Received close confirmation for "
2130 "out-of-range channel %d.", id);
2131 if (c->type != SSH_CHANNEL_CLOSED)
2132 packet_disconnect("Received close confirmation for "
2133 "non-closed channel %d (type %d).", id, c->type);
2138 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2143 id = packet_get_int();
2144 c = channel_lookup(id);
2146 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2147 packet_disconnect("Received open confirmation for "
2148 "non-opening channel %d.", id);
2149 remote_id = packet_get_int();
2150 /* Record the remote channel number and mark that the channel is now open. */
2151 c->remote_id = remote_id;
2152 c->type = SSH_CHANNEL_OPEN;
2155 c->remote_window = packet_get_int();
2156 c->remote_maxpacket = packet_get_int();
2158 debug2("callback start");
2159 c->confirm(c->self, c->confirm_ctx);
2160 debug2("callback done");
2162 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2163 c->remote_window, c->remote_maxpacket);
2169 reason2txt(int reason)
2172 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2173 return "administratively prohibited";
2174 case SSH2_OPEN_CONNECT_FAILED:
2175 return "connect failed";
2176 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2177 return "unknown channel type";
2178 case SSH2_OPEN_RESOURCE_SHORTAGE:
2179 return "resource shortage";
2181 return "unknown reason";
2185 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2188 char *msg = NULL, *lang = NULL;
2191 id = packet_get_int();
2192 c = channel_lookup(id);
2194 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2195 packet_disconnect("Received open failure for "
2196 "non-opening channel %d.", id);
2198 reason = packet_get_int();
2199 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2200 msg = packet_get_string(NULL);
2201 lang = packet_get_string(NULL);
2203 logit("channel %d: open failed: %s%s%s", id,
2204 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2211 /* Free the channel. This will also close the socket. */
2216 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2225 /* Get the channel number and verify it. */
2226 id = packet_get_int();
2227 c = channel_lookup(id);
2230 logit("Received window adjust for non-open channel %d.", id);
2233 adjust = packet_get_int();
2235 debug2("channel %d: rcvd adjust %u", id, adjust);
2236 c->remote_window += adjust;
2240 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2244 char *host, *originator_string;
2245 int remote_id, sock = -1;
2247 remote_id = packet_get_int();
2248 host = packet_get_string(NULL);
2249 host_port = packet_get_int();
2251 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2252 originator_string = packet_get_string(NULL);
2254 originator_string = xstrdup("unknown (remote did not supply name)");
2257 sock = channel_connect_to(host, host_port);
2259 c = channel_new("connected socket",
2260 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2261 originator_string, 1);
2262 c->remote_id = remote_id;
2264 xfree(originator_string);
2266 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2267 packet_put_int(remote_id);
2274 /* -- tcp forwarding */
2277 channel_set_af(int af)
2283 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2284 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2287 int sock, r, success = 0, wildcard = 0, is_client;
2288 struct addrinfo hints, *ai, *aitop;
2289 const char *host, *addr;
2290 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2292 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2293 listen_addr : host_to_connect;
2294 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2297 error("No forward host name.");
2300 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2301 error("Forward host name too long.");
2306 * Determine whether or not a port forward listens to loopback,
2307 * specified address or wildcard. On the client, a specified bind
2308 * address will always override gateway_ports. On the server, a
2309 * gateway_ports of 1 (``yes'') will override the client's
2310 * specification and force a wildcard bind, whereas a value of 2
2311 * (``clientspecified'') will bind to whatever address the client
2314 * Special-case listen_addrs are:
2316 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2317 * "" (empty string), "*" -> wildcard v4/v6
2318 * "localhost" -> loopback v4/v6
2321 if (listen_addr == NULL) {
2322 /* No address specified: default to gateway_ports setting */
2325 } else if (gateway_ports || is_client) {
2326 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2327 strcmp(listen_addr, "0.0.0.0") == 0) ||
2328 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2329 (!is_client && gateway_ports == 1))
2331 else if (strcmp(listen_addr, "localhost") != 0)
2335 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2336 type, wildcard, (addr == NULL) ? "NULL" : addr);
2339 * getaddrinfo returns a loopback address if the hostname is
2340 * set to NULL and hints.ai_flags is not AI_PASSIVE
2342 memset(&hints, 0, sizeof(hints));
2343 hints.ai_family = IPv4or6;
2344 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2345 hints.ai_socktype = SOCK_STREAM;
2346 snprintf(strport, sizeof strport, "%d", listen_port);
2347 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2349 /* This really shouldn't happen */
2350 packet_disconnect("getaddrinfo: fatal error: %s",
2353 error("channel_setup_fwd_listener: "
2354 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2359 for (ai = aitop; ai; ai = ai->ai_next) {
2360 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2362 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2363 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2364 error("channel_setup_fwd_listener: getnameinfo failed");
2367 /* Create a port to listen for the host. */
2368 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2370 /* this is no error since kernel may not support ipv6 */
2371 verbose("socket: %.100s", strerror(errno));
2375 channel_set_reuseaddr(sock);
2377 debug("Local forwarding listening on %s port %s.", ntop, strport);
2379 /* Bind the socket to the address. */
2380 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2381 /* address can be in use ipv6 address is already bound */
2383 error("bind: %.100s", strerror(errno));
2385 verbose("bind: %.100s", strerror(errno));
2390 /* Start listening for connections on the socket. */
2391 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2392 error("listen: %.100s", strerror(errno));
2396 /* Allocate a channel number for the socket. */
2397 c = channel_new("port listener", type, sock, sock, -1,
2398 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2399 0, "port listener", 1);
2400 strlcpy(c->path, host, sizeof(c->path));
2401 c->host_port = port_to_connect;
2402 c->listening_port = listen_port;
2406 error("channel_setup_fwd_listener: cannot listen to port: %d",
2408 freeaddrinfo(aitop);
2413 channel_cancel_rport_listener(const char *host, u_short port)
2418 for (i = 0; i < channels_alloc; i++) {
2419 Channel *c = channels[i];
2421 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2422 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2423 c->listening_port == port) {
2424 debug2("%s: close channel %d", __func__, i);
2433 /* protocol local port fwd, used by ssh (and sshd in v1) */
2435 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2436 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2438 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2439 listen_host, listen_port, host_to_connect, port_to_connect,
2443 /* protocol v2 remote port fwd, used by sshd */
2445 channel_setup_remote_fwd_listener(const char *listen_address,
2446 u_short listen_port, int gateway_ports)
2448 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2449 listen_address, listen_port, NULL, 0, gateway_ports);
2453 * Initiate forwarding of connections to port "port" on remote host through
2454 * the secure channel to host:port from local side.
2458 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2459 const char *host_to_connect, u_short port_to_connect)
2461 int type, success = 0;
2463 /* Record locally that connection to this host/port is permitted. */
2464 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2465 fatal("channel_request_remote_forwarding: too many forwards");
2467 /* Send the forward request to the remote side. */
2469 const char *address_to_bind;
2470 if (listen_host == NULL)
2471 address_to_bind = "localhost";
2472 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2473 address_to_bind = "";
2475 address_to_bind = listen_host;
2477 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2478 packet_put_cstring("tcpip-forward");
2479 packet_put_char(1); /* boolean: want reply */
2480 packet_put_cstring(address_to_bind);
2481 packet_put_int(listen_port);
2483 packet_write_wait();
2484 /* Assume that server accepts the request */
2487 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2488 packet_put_int(listen_port);
2489 packet_put_cstring(host_to_connect);
2490 packet_put_int(port_to_connect);
2492 packet_write_wait();
2494 /* Wait for response from the remote side. */
2495 type = packet_read();
2497 case SSH_SMSG_SUCCESS:
2500 case SSH_SMSG_FAILURE:
2501 logit("Warning: Server denied remote port forwarding.");
2504 /* Unknown packet */
2505 packet_disconnect("Protocol error for port forward request:"
2506 "received packet type %d.", type);
2510 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2511 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2512 permitted_opens[num_permitted_opens].listen_port = listen_port;
2513 num_permitted_opens++;
2518 * Request cancellation of remote forwarding of connection host:port from
2522 channel_request_rforward_cancel(const char *host, u_short port)
2529 for (i = 0; i < num_permitted_opens; i++) {
2530 if (permitted_opens[i].host_to_connect != NULL &&
2531 permitted_opens[i].listen_port == port)
2534 if (i >= num_permitted_opens) {
2535 debug("%s: requested forward not found", __func__);
2538 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2539 packet_put_cstring("cancel-tcpip-forward");
2541 packet_put_cstring(host == NULL ? "" : host);
2542 packet_put_int(port);
2545 permitted_opens[i].listen_port = 0;
2546 permitted_opens[i].port_to_connect = 0;
2547 xfree(permitted_opens[i].host_to_connect);
2548 permitted_opens[i].host_to_connect = NULL;
2552 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2553 * listening for the port, and sends back a success reply (or disconnect
2554 * message if there was an error). This never returns if there was an error.
2558 channel_input_port_forward_request(int is_root, int gateway_ports)
2560 u_short port, host_port;
2563 /* Get arguments from the packet. */
2564 port = packet_get_int();
2565 hostname = packet_get_string(NULL);
2566 host_port = packet_get_int();
2570 * Check that an unprivileged user is not trying to forward a
2573 if (port < IPPORT_RESERVED && !is_root)
2575 "Requested forwarding of port %d but user is not root.",
2578 packet_disconnect("Dynamic forwarding denied.");
2581 /* Initiate forwarding */
2582 channel_setup_local_fwd_listener(NULL, port, hostname,
2583 host_port, gateway_ports);
2585 /* Free the argument string. */
2590 * Permits opening to any host/port if permitted_opens[] is empty. This is
2591 * usually called by the server, because the user could connect to any port
2592 * anyway, and the server has no way to know but to trust the client anyway.
2595 channel_permit_all_opens(void)
2597 if (num_permitted_opens == 0)
2598 all_opens_permitted = 1;
2602 channel_add_permitted_opens(char *host, int port)
2604 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2605 fatal("channel_request_remote_forwarding: too many forwards");
2606 debug("allow port forwarding to host %s port %d", host, port);
2608 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2609 permitted_opens[num_permitted_opens].port_to_connect = port;
2610 num_permitted_opens++;
2612 all_opens_permitted = 0;
2616 channel_clear_permitted_opens(void)
2620 for (i = 0; i < num_permitted_opens; i++)
2621 if (permitted_opens[i].host_to_connect != NULL)
2622 xfree(permitted_opens[i].host_to_connect);
2623 num_permitted_opens = 0;
2628 /* return socket to remote host, port */
2630 connect_to(const char *host, u_short port)
2632 struct addrinfo hints, *ai, *aitop;
2633 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2637 memset(&hints, 0, sizeof(hints));
2638 hints.ai_family = IPv4or6;
2639 hints.ai_socktype = SOCK_STREAM;
2640 snprintf(strport, sizeof strport, "%d", port);
2641 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2642 error("connect_to %.100s: unknown host (%s)", host,
2643 gai_strerror(gaierr));
2646 for (ai = aitop; ai; ai = ai->ai_next) {
2647 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2649 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2650 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2651 error("connect_to: getnameinfo failed");
2654 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2656 if (ai->ai_next == NULL)
2657 error("socket: %.100s", strerror(errno));
2659 verbose("socket: %.100s", strerror(errno));
2662 if (set_nonblock(sock) == -1)
2663 fatal("%s: set_nonblock(%d)", __func__, sock);
2664 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2665 errno != EINPROGRESS) {
2666 error("connect_to %.100s port %s: %.100s", ntop, strport,
2669 continue; /* fail -- try next */
2671 break; /* success */
2674 freeaddrinfo(aitop);
2676 error("connect_to %.100s port %d: failed.", host, port);
2685 channel_connect_by_listen_address(u_short listen_port)
2689 for (i = 0; i < num_permitted_opens; i++)
2690 if (permitted_opens[i].host_to_connect != NULL &&
2691 permitted_opens[i].listen_port == listen_port)
2693 permitted_opens[i].host_to_connect,
2694 permitted_opens[i].port_to_connect);
2695 error("WARNING: Server requests forwarding for unknown listen_port %d",
2700 /* Check if connecting to that port is permitted and connect. */
2702 channel_connect_to(const char *host, u_short port)
2706 permit = all_opens_permitted;
2708 for (i = 0; i < num_permitted_opens; i++)
2709 if (permitted_opens[i].host_to_connect != NULL &&
2710 permitted_opens[i].port_to_connect == port &&
2711 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2716 logit("Received request to connect to host %.100s port %d, "
2717 "but the request was denied.", host, port);
2720 return connect_to(host, port);
2724 channel_send_window_changes(void)
2729 for (i = 0; i < channels_alloc; i++) {
2730 if (channels[i] == NULL || !channels[i]->client_tty ||
2731 channels[i]->type != SSH_CHANNEL_OPEN)
2733 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2735 channel_request_start(i, "window-change", 0);
2736 packet_put_int(ws.ws_col);
2737 packet_put_int(ws.ws_row);
2738 packet_put_int(ws.ws_xpixel);
2739 packet_put_int(ws.ws_ypixel);
2744 /* -- X11 forwarding */
2747 * Creates an internet domain socket for listening for X11 connections.
2748 * Returns 0 and a suitable display number for the DISPLAY variable
2749 * stored in display_numberp , or -1 if an error occurs.
2752 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2753 int single_connection, u_int *display_numberp, int **chanids)
2756 int display_number, sock;
2758 struct addrinfo hints, *ai, *aitop;
2759 char strport[NI_MAXSERV];
2760 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2762 if (chanids == NULL)
2765 for (display_number = x11_display_offset;
2766 display_number < MAX_DISPLAYS;
2768 port = 6000 + display_number;
2769 memset(&hints, 0, sizeof(hints));
2770 hints.ai_family = IPv4or6;
2771 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2772 hints.ai_socktype = SOCK_STREAM;
2773 snprintf(strport, sizeof strport, "%d", port);
2774 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2775 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2778 for (ai = aitop; ai; ai = ai->ai_next) {
2779 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2781 sock = socket(ai->ai_family, ai->ai_socktype,
2784 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2785 error("socket: %.100s", strerror(errno));
2786 freeaddrinfo(aitop);
2789 debug("x11_create_display_inet: Socket family %d not supported",
2795 if (ai->ai_family == AF_INET6) {
2797 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2798 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2801 channel_set_reuseaddr(sock);
2802 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2803 debug2("bind port %d: %.100s", port, strerror(errno));
2809 for (n = 0; n < num_socks; n++) {
2815 socks[num_socks++] = sock;
2816 #ifndef DONT_TRY_OTHER_AF
2817 if (num_socks == NUM_SOCKS)
2820 if (x11_use_localhost) {
2821 if (num_socks == NUM_SOCKS)
2828 freeaddrinfo(aitop);
2832 if (display_number >= MAX_DISPLAYS) {
2833 error("Failed to allocate internet-domain X11 display socket.");
2836 /* Start listening for connections on the socket. */
2837 for (n = 0; n < num_socks; n++) {
2839 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2840 error("listen: %.100s", strerror(errno));
2846 /* Allocate a channel for each socket. */
2847 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1));
2848 for (n = 0; n < num_socks; n++) {
2850 nc = channel_new("x11 listener",
2851 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2852 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2853 0, "X11 inet listener", 1);
2854 nc->single_connection = single_connection;
2855 (*chanids)[n] = nc->self;
2859 /* Return the display number for the DISPLAY environment variable. */
2860 *display_numberp = display_number;
2865 connect_local_xsocket(u_int dnr)
2868 struct sockaddr_un addr;
2870 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2872 error("socket: %.100s", strerror(errno));
2873 memset(&addr, 0, sizeof(addr));
2874 addr.sun_family = AF_UNIX;
2875 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2876 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2879 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2884 x11_connect_display(void)
2886 int display_number, sock = 0;
2887 const char *display;
2888 char buf[1024], *cp;
2889 struct addrinfo hints, *ai, *aitop;
2890 char strport[NI_MAXSERV];
2893 /* Try to open a socket for the local X server. */
2894 display = getenv("DISPLAY");
2896 error("DISPLAY not set.");
2900 * Now we decode the value of the DISPLAY variable and make a
2901 * connection to the real X server.
2905 * Check if it is a unix domain socket. Unix domain displays are in
2906 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2908 if (strncmp(display, "unix:", 5) == 0 ||
2909 display[0] == ':') {
2910 /* Connect to the unix domain socket. */
2911 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2912 error("Could not parse display number from DISPLAY: %.100s",
2916 /* Create a socket. */
2917 sock = connect_local_xsocket(display_number);
2921 /* OK, we now have a connection to the display. */
2925 * Connect to an inet socket. The DISPLAY value is supposedly
2926 * hostname:d[.s], where hostname may also be numeric IP address.
2928 strlcpy(buf, display, sizeof(buf));
2929 cp = strchr(buf, ':');
2931 error("Could not find ':' in DISPLAY: %.100s", display);
2935 /* buf now contains the host name. But first we parse the display number. */
2936 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2937 error("Could not parse display number from DISPLAY: %.100s",
2942 /* Look up the host address */
2943 memset(&hints, 0, sizeof(hints));
2944 hints.ai_family = IPv4or6;
2945 hints.ai_socktype = SOCK_STREAM;
2946 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2947 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2948 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2951 for (ai = aitop; ai; ai = ai->ai_next) {
2952 /* Create a socket. */
2953 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2955 debug2("socket: %.100s", strerror(errno));
2958 /* Connect it to the display. */
2959 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2960 debug2("connect %.100s port %d: %.100s", buf,
2961 6000 + display_number, strerror(errno));
2968 freeaddrinfo(aitop);
2970 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2979 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2980 * the remote channel number. We should do whatever we want, and respond
2981 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2985 x11_input_open(int type, u_int32_t seq, void *ctxt)
2988 int remote_id, sock = 0;
2991 debug("Received X11 open request.");
2993 remote_id = packet_get_int();
2995 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2996 remote_host = packet_get_string(NULL);
2998 remote_host = xstrdup("unknown (remote did not supply name)");
3002 /* Obtain a connection to the real X display. */
3003 sock = x11_connect_display();
3005 /* Allocate a channel for this connection. */
3006 c = channel_new("connected x11 socket",
3007 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3009 c->remote_id = remote_id;
3014 /* Send refusal to the remote host. */
3015 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3016 packet_put_int(remote_id);
3018 /* Send a confirmation to the remote host. */
3019 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3020 packet_put_int(remote_id);
3021 packet_put_int(c->self);
3026 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3028 deny_input_open(int type, u_int32_t seq, void *ctxt)
3030 int rchan = packet_get_int();
3033 case SSH_SMSG_AGENT_OPEN:
3034 error("Warning: ssh server tried agent forwarding.");
3036 case SSH_SMSG_X11_OPEN:
3037 error("Warning: ssh server tried X11 forwarding.");
3040 error("deny_input_open: type %d", type);
3043 error("Warning: this is probably a break-in attempt by a malicious server.");
3044 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3045 packet_put_int(rchan);
3050 * Requests forwarding of X11 connections, generates fake authentication
3051 * data, and enables authentication spoofing.
3052 * This should be called in the client only.
3055 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3056 const char *proto, const char *data)
3058 u_int data_len = (u_int) strlen(data) / 2;
3065 if (x11_saved_display == NULL)
3066 x11_saved_display = xstrdup(disp);
3067 else if (strcmp(disp, x11_saved_display) != 0) {
3068 error("x11_request_forwarding_with_spoofing: different "
3069 "$DISPLAY already forwarded");
3075 cp = strchr(disp, ':');
3077 cp = strchr(cp, '.');
3079 screen_number = atoi(cp + 1);
3083 if (x11_saved_proto == NULL) {
3084 /* Save protocol name. */
3085 x11_saved_proto = xstrdup(proto);
3087 * Extract real authentication data and generate fake data
3088 * of the same length.
3090 x11_saved_data = xmalloc(data_len);
3091 x11_fake_data = xmalloc(data_len);
3092 for (i = 0; i < data_len; i++) {
3093 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3094 fatal("x11_request_forwarding: bad "
3095 "authentication data: %.100s", data);
3098 x11_saved_data[i] = value;
3099 x11_fake_data[i] = rnd & 0xff;
3102 x11_saved_data_len = data_len;
3103 x11_fake_data_len = data_len;
3106 /* Convert the fake data into hex. */
3107 new_data = tohex(x11_fake_data, data_len);
3109 /* Send the request packet. */
3111 channel_request_start(client_session_id, "x11-req", 0);
3112 packet_put_char(0); /* XXX bool single connection */
3114 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3116 packet_put_cstring(proto);
3117 packet_put_cstring(new_data);
3118 packet_put_int(screen_number);
3120 packet_write_wait();
3125 /* -- agent forwarding */
3127 /* Sends a message to the server to request authentication fd forwarding. */
3130 auth_request_forwarding(void)
3132 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3134 packet_write_wait();