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.
43 #include <sys/ioctl.h>
44 #include <sys/types.h>
61 #include "pathnames.h"
67 * Pointer to an array containing all allocated channels. The array is
68 * dynamically extended as needed.
70 static Channel **channels = NULL;
73 * Size of the channel array. All slots of the array must always be
74 * initialized (at least the type field); unused slots set to NULL
76 static u_int channels_alloc = 0;
79 * Maximum file descriptor value used in any of the channels. This is
80 * updated in channel_new.
82 static int channel_max_fd = 0;
85 /* -- tcp forwarding */
88 * Data structure for storing which hosts are permitted for forward requests.
89 * The local sides of any remote forwards are stored in this array to prevent
90 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
91 * network (which might be behind a firewall).
94 char *host_to_connect; /* Connect to 'host'. */
95 u_short port_to_connect; /* Connect to 'port'. */
96 u_short listen_port; /* Remote side should listen port number. */
99 /* List of all permitted host/port pairs to connect. */
100 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
102 /* Number of permitted host/port pairs in the array. */
103 static int num_permitted_opens = 0;
105 * If this is true, all opens are permitted. This is the case on the server
106 * on which we have to trust the client anyway, and the user could do
107 * anything after logging in anyway.
109 static int all_opens_permitted = 0;
112 /* -- X11 forwarding */
114 /* Maximum number of fake X11 displays to try. */
115 #define MAX_DISPLAYS 1000
117 /* Saved X11 local (client) display. */
118 static char *x11_saved_display = NULL;
120 /* Saved X11 authentication protocol name. */
121 static char *x11_saved_proto = NULL;
123 /* Saved X11 authentication data. This is the real data. */
124 static char *x11_saved_data = NULL;
125 static u_int x11_saved_data_len = 0;
128 * Fake X11 authentication data. This is what the server will be sending us;
129 * we should replace any occurrences of this by the real data.
131 static u_char *x11_fake_data = NULL;
132 static u_int x11_fake_data_len;
135 /* -- agent forwarding */
139 /* AF_UNSPEC or AF_INET or AF_INET6 */
140 static int IPv4or6 = AF_UNSPEC;
143 static void port_open_helper(Channel *c, char *rtype);
145 /* -- channel core */
148 channel_by_id(int id)
152 if (id < 0 || (u_int)id >= channels_alloc) {
153 logit("channel_by_id: %d: bad id", id);
158 logit("channel_by_id: %d: bad id: channel free", id);
165 * Returns the channel if it is allowed to receive protocol messages.
166 * Private channels, like listening sockets, may not receive messages.
169 channel_lookup(int id)
173 if ((c = channel_by_id(id)) == NULL)
177 case SSH_CHANNEL_X11_OPEN:
178 case SSH_CHANNEL_LARVAL:
179 case SSH_CHANNEL_CONNECTING:
180 case SSH_CHANNEL_DYNAMIC:
181 case SSH_CHANNEL_OPENING:
182 case SSH_CHANNEL_OPEN:
183 case SSH_CHANNEL_INPUT_DRAINING:
184 case SSH_CHANNEL_OUTPUT_DRAINING:
187 logit("Non-public channel %d, type %d.", id, c->type);
192 * Register filedescriptors for a channel, used when allocating a channel or
193 * when the channel consumer/producer is ready, e.g. shell exec'd
196 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
197 int extusage, int nonblock)
199 /* Update the maximum file descriptor value. */
200 channel_max_fd = MAX(channel_max_fd, rfd);
201 channel_max_fd = MAX(channel_max_fd, wfd);
202 channel_max_fd = MAX(channel_max_fd, efd);
204 /* XXX set close-on-exec -markus */
208 c->sock = (rfd == wfd) ? rfd : -1;
209 c->ctl_fd = -1; /* XXX: set elsewhere */
211 c->extended_usage = extusage;
213 /* XXX ugly hack: nonblock is only set by the server */
214 if (nonblock && isatty(c->rfd)) {
215 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
217 if (!isatty(c->wfd)) {
218 error("channel %d: wfd %d is not a tty?",
224 c->wfd_isatty = isatty(c->wfd);
226 /* enable nonblocking mode */
238 * Allocate a new channel object and set its type and socket. This will cause
239 * remote_name to be freed.
242 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
243 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
249 /* Do initial allocation if this is the first call. */
250 if (channels_alloc == 0) {
252 channels = xcalloc(channels_alloc, sizeof(Channel *));
253 for (i = 0; i < channels_alloc; i++)
256 /* Try to find a free slot where to put the new channel. */
257 for (found = -1, i = 0; i < channels_alloc; i++)
258 if (channels[i] == NULL) {
259 /* Found a free slot. */
264 /* There are no free slots. Take last+1 slot and expand the array. */
265 found = channels_alloc;
266 if (channels_alloc > 10000)
267 fatal("channel_new: internal error: channels_alloc %d "
268 "too big.", channels_alloc);
269 channels = xrealloc(channels,
270 (channels_alloc + 10) * sizeof(Channel *));
271 channels_alloc += 10;
272 debug2("channel: expanding %d", channels_alloc);
273 for (i = found; i < channels_alloc; i++)
276 /* Initialize and return new channel. */
277 c = channels[found] = xcalloc(1, sizeof(Channel));
278 buffer_init(&c->input);
279 buffer_init(&c->output);
280 buffer_init(&c->extended);
281 c->ostate = CHAN_OUTPUT_OPEN;
282 c->istate = CHAN_INPUT_OPEN;
284 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
288 c->local_window = window;
289 c->local_window_max = window;
290 c->local_consumed = 0;
291 c->local_maxpacket = maxpack;
293 c->remote_name = xstrdup(remote_name);
294 c->remote_window = 0;
295 c->remote_maxpacket = 0;
297 c->single_connection = 0;
298 c->detach_user = NULL;
301 c->confirm_ctx = NULL;
302 c->input_filter = NULL;
303 c->output_filter = NULL;
304 debug("channel %d: new [%s]", found, remote_name);
309 channel_find_maxfd(void)
315 for (i = 0; i < channels_alloc; i++) {
318 max = MAX(max, c->rfd);
319 max = MAX(max, c->wfd);
320 max = MAX(max, c->efd);
327 channel_close_fd(int *fdp)
329 int ret = 0, fd = *fdp;
334 if (fd == channel_max_fd)
335 channel_max_fd = channel_find_maxfd();
340 /* 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. */
356 channel_free(Channel *c)
361 for (n = 0, i = 0; i < channels_alloc; i++)
364 debug("channel %d: free: %s, nchannels %u", c->self,
365 c->remote_name ? c->remote_name : "???", n);
367 s = channel_open_message();
368 debug3("channel %d: status: %s", c->self, s);
372 shutdown(c->sock, SHUT_RDWR);
374 shutdown(c->ctl_fd, SHUT_RDWR);
375 channel_close_fds(c);
376 buffer_free(&c->input);
377 buffer_free(&c->output);
378 buffer_free(&c->extended);
379 if (c->remote_name) {
380 xfree(c->remote_name);
381 c->remote_name = NULL;
383 channels[c->self] = NULL;
388 channel_free_all(void)
392 for (i = 0; i < channels_alloc; i++)
393 if (channels[i] != NULL)
394 channel_free(channels[i]);
398 * Closes the sockets/fds of all channels. This is used to close extra file
399 * descriptors after a fork.
402 channel_close_all(void)
406 for (i = 0; i < channels_alloc; i++)
407 if (channels[i] != NULL)
408 channel_close_fds(channels[i]);
412 * Stop listening to channels.
415 channel_stop_listening(void)
420 for (i = 0; i < channels_alloc; i++) {
424 case SSH_CHANNEL_AUTH_SOCKET:
425 case SSH_CHANNEL_PORT_LISTENER:
426 case SSH_CHANNEL_RPORT_LISTENER:
427 case SSH_CHANNEL_X11_LISTENER:
428 channel_close_fd(&c->sock);
437 * Returns true if no channel has too much buffered data, and false if one or
438 * more channel is overfull.
441 channel_not_very_much_buffered_data(void)
446 for (i = 0; i < channels_alloc; i++) {
448 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
451 buffer_len(&c->input) > packet_get_maxsize()) {
452 debug2("channel %d: big input buffer %d",
453 c->self, buffer_len(&c->input));
457 if (buffer_len(&c->output) > packet_get_maxsize()) {
458 debug2("channel %d: big output buffer %u > %u",
459 c->self, buffer_len(&c->output),
460 packet_get_maxsize());
468 /* Returns true if any channel is still open. */
470 channel_still_open(void)
475 for (i = 0; i < channels_alloc; i++) {
480 case SSH_CHANNEL_X11_LISTENER:
481 case SSH_CHANNEL_PORT_LISTENER:
482 case SSH_CHANNEL_RPORT_LISTENER:
483 case SSH_CHANNEL_CLOSED:
484 case SSH_CHANNEL_AUTH_SOCKET:
485 case SSH_CHANNEL_DYNAMIC:
486 case SSH_CHANNEL_CONNECTING:
487 case SSH_CHANNEL_ZOMBIE:
489 case SSH_CHANNEL_LARVAL:
491 fatal("cannot happen: SSH_CHANNEL_LARVAL");
493 case SSH_CHANNEL_OPENING:
494 case SSH_CHANNEL_OPEN:
495 case SSH_CHANNEL_X11_OPEN:
497 case SSH_CHANNEL_INPUT_DRAINING:
498 case SSH_CHANNEL_OUTPUT_DRAINING:
500 fatal("cannot happen: OUT_DRAIN");
503 fatal("channel_still_open: bad channel type %d", c->type);
510 /* Returns the id of an open channel suitable for keepaliving */
512 channel_find_open(void)
517 for (i = 0; i < channels_alloc; i++) {
519 if (c == NULL || c->remote_id < 0)
522 case SSH_CHANNEL_CLOSED:
523 case SSH_CHANNEL_DYNAMIC:
524 case SSH_CHANNEL_X11_LISTENER:
525 case SSH_CHANNEL_PORT_LISTENER:
526 case SSH_CHANNEL_RPORT_LISTENER:
527 case SSH_CHANNEL_OPENING:
528 case SSH_CHANNEL_CONNECTING:
529 case SSH_CHANNEL_ZOMBIE:
531 case SSH_CHANNEL_LARVAL:
532 case SSH_CHANNEL_AUTH_SOCKET:
533 case SSH_CHANNEL_OPEN:
534 case SSH_CHANNEL_X11_OPEN:
536 case SSH_CHANNEL_INPUT_DRAINING:
537 case SSH_CHANNEL_OUTPUT_DRAINING:
539 fatal("cannot happen: OUT_DRAIN");
542 fatal("channel_find_open: bad channel type %d", c->type);
551 * Returns a message describing the currently open forwarded connections,
552 * suitable for sending to the client. The message contains crlf pairs for
556 channel_open_message(void)
563 buffer_init(&buffer);
564 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
565 buffer_append(&buffer, buf, strlen(buf));
566 for (i = 0; i < channels_alloc; i++) {
571 case SSH_CHANNEL_X11_LISTENER:
572 case SSH_CHANNEL_PORT_LISTENER:
573 case SSH_CHANNEL_RPORT_LISTENER:
574 case SSH_CHANNEL_CLOSED:
575 case SSH_CHANNEL_AUTH_SOCKET:
576 case SSH_CHANNEL_ZOMBIE:
578 case SSH_CHANNEL_LARVAL:
579 case SSH_CHANNEL_OPENING:
580 case SSH_CHANNEL_CONNECTING:
581 case SSH_CHANNEL_DYNAMIC:
582 case SSH_CHANNEL_OPEN:
583 case SSH_CHANNEL_X11_OPEN:
584 case SSH_CHANNEL_INPUT_DRAINING:
585 case SSH_CHANNEL_OUTPUT_DRAINING:
586 snprintf(buf, sizeof buf,
587 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
588 c->self, c->remote_name,
589 c->type, c->remote_id,
590 c->istate, buffer_len(&c->input),
591 c->ostate, buffer_len(&c->output),
592 c->rfd, c->wfd, c->ctl_fd);
593 buffer_append(&buffer, buf, strlen(buf));
596 fatal("channel_open_message: bad channel type %d", c->type);
600 buffer_append(&buffer, "\0", 1);
601 cp = xstrdup(buffer_ptr(&buffer));
602 buffer_free(&buffer);
607 channel_send_open(int id)
609 Channel *c = channel_lookup(id);
612 logit("channel_send_open: %d: bad id", id);
615 debug2("channel %d: send open", id);
616 packet_start(SSH2_MSG_CHANNEL_OPEN);
617 packet_put_cstring(c->ctype);
618 packet_put_int(c->self);
619 packet_put_int(c->local_window);
620 packet_put_int(c->local_maxpacket);
625 channel_request_start(int id, char *service, int wantconfirm)
627 Channel *c = channel_lookup(id);
630 logit("channel_request_start: %d: unknown channel id", id);
633 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
634 packet_start(SSH2_MSG_CHANNEL_REQUEST);
635 packet_put_int(c->remote_id);
636 packet_put_cstring(service);
637 packet_put_char(wantconfirm);
641 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
643 Channel *c = channel_lookup(id);
646 logit("channel_register_comfirm: %d: bad id", id);
650 c->confirm_ctx = ctx;
654 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
656 Channel *c = channel_by_id(id);
659 logit("channel_register_cleanup: %d: bad id", id);
663 c->detach_close = do_close;
667 channel_cancel_cleanup(int id)
669 Channel *c = channel_by_id(id);
672 logit("channel_cancel_cleanup: %d: bad id", id);
675 c->detach_user = NULL;
680 channel_register_filter(int id, channel_infilter_fn *ifn,
681 channel_outfilter_fn *ofn)
683 Channel *c = channel_lookup(id);
686 logit("channel_register_filter: %d: bad id", id);
689 c->input_filter = ifn;
690 c->output_filter = ofn;
694 channel_set_fds(int id, int rfd, int wfd, int efd,
695 int extusage, int nonblock, u_int window_max)
697 Channel *c = channel_lookup(id);
699 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
700 fatal("channel_activate for non-larval channel %d.", id);
701 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
702 c->type = SSH_CHANNEL_OPEN;
703 c->local_window = c->local_window_max = window_max;
704 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
705 packet_put_int(c->remote_id);
706 packet_put_int(c->local_window);
711 * 'channel_pre*' are called just before select() to add any bits relevant to
712 * channels in the select bitmasks.
715 * 'channel_post*': perform any appropriate operations for channels which
716 * have events pending.
718 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
719 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
720 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
723 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
725 FD_SET(c->sock, readset);
729 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
731 debug3("channel %d: waiting for connection", c->self);
732 FD_SET(c->sock, writeset);
736 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
738 if (buffer_len(&c->input) < packet_get_maxsize())
739 FD_SET(c->sock, readset);
740 if (buffer_len(&c->output) > 0)
741 FD_SET(c->sock, writeset);
745 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
747 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
749 /* check buffer limits */
750 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
752 if (c->istate == CHAN_INPUT_OPEN &&
754 buffer_len(&c->input) < limit)
755 FD_SET(c->rfd, readset);
756 if (c->ostate == CHAN_OUTPUT_OPEN ||
757 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
758 if (buffer_len(&c->output) > 0) {
759 FD_SET(c->wfd, writeset);
760 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
761 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
762 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
763 c->self, c->efd, buffer_len(&c->extended));
768 /** XXX check close conditions, too */
769 if (compat20 && c->efd != -1) {
770 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
771 buffer_len(&c->extended) > 0)
772 FD_SET(c->efd, writeset);
773 else if (!(c->flags & CHAN_EOF_SENT) &&
774 c->extended_usage == CHAN_EXTENDED_READ &&
775 buffer_len(&c->extended) < c->remote_window)
776 FD_SET(c->efd, readset);
778 /* XXX: What about efd? races? */
779 if (compat20 && c->ctl_fd != -1 &&
780 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
781 FD_SET(c->ctl_fd, readset);
785 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
787 if (buffer_len(&c->input) == 0) {
788 packet_start(SSH_MSG_CHANNEL_CLOSE);
789 packet_put_int(c->remote_id);
791 c->type = SSH_CHANNEL_CLOSED;
792 debug2("channel %d: closing after input drain.", c->self);
797 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
799 if (buffer_len(&c->output) == 0)
802 FD_SET(c->sock, writeset);
806 * This is a special state for X11 authentication spoofing. An opened X11
807 * connection (when authentication spoofing is being done) remains in this
808 * state until the first packet has been completely read. The authentication
809 * data in that packet is then substituted by the real data if it matches the
810 * fake data, and the channel is put into normal mode.
811 * XXX All this happens at the client side.
812 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
815 x11_open_helper(Buffer *b)
818 u_int proto_len, data_len;
820 /* Check if the fixed size part of the packet is in buffer. */
821 if (buffer_len(b) < 12)
824 /* Parse the lengths of variable-length fields. */
826 if (ucp[0] == 0x42) { /* Byte order MSB first. */
827 proto_len = 256 * ucp[6] + ucp[7];
828 data_len = 256 * ucp[8] + ucp[9];
829 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
830 proto_len = ucp[6] + 256 * ucp[7];
831 data_len = ucp[8] + 256 * ucp[9];
833 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
838 /* Check if the whole packet is in buffer. */
840 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
843 /* Check if authentication protocol matches. */
844 if (proto_len != strlen(x11_saved_proto) ||
845 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
846 debug2("X11 connection uses different authentication protocol.");
849 /* Check if authentication data matches our fake data. */
850 if (data_len != x11_fake_data_len ||
851 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
852 x11_fake_data, x11_fake_data_len) != 0) {
853 debug2("X11 auth data does not match fake data.");
856 /* Check fake data length */
857 if (x11_fake_data_len != x11_saved_data_len) {
858 error("X11 fake_data_len %d != saved_data_len %d",
859 x11_fake_data_len, x11_saved_data_len);
863 * Received authentication protocol and data match
864 * our fake data. Substitute the fake data with real
867 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
868 x11_saved_data, x11_saved_data_len);
873 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
875 int ret = x11_open_helper(&c->output);
878 /* Start normal processing for the channel. */
879 c->type = SSH_CHANNEL_OPEN;
880 channel_pre_open_13(c, readset, writeset);
881 } else if (ret == -1) {
883 * We have received an X11 connection that has bad
884 * authentication information.
886 logit("X11 connection rejected because of wrong authentication.");
887 buffer_clear(&c->input);
888 buffer_clear(&c->output);
889 channel_close_fd(&c->sock);
891 c->type = SSH_CHANNEL_CLOSED;
892 packet_start(SSH_MSG_CHANNEL_CLOSE);
893 packet_put_int(c->remote_id);
899 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
901 int ret = x11_open_helper(&c->output);
903 /* c->force_drain = 1; */
906 c->type = SSH_CHANNEL_OPEN;
907 channel_pre_open(c, readset, writeset);
908 } else if (ret == -1) {
909 logit("X11 connection rejected because of wrong authentication.");
910 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
912 buffer_clear(&c->input);
914 buffer_clear(&c->output);
915 /* for proto v1, the peer will send an IEOF */
917 chan_write_failed(c);
919 c->type = SSH_CHANNEL_OPEN;
920 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
924 /* try to decode a socks4 header */
926 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
929 u_int len, have, i, found;
935 struct in_addr dest_addr;
938 debug2("channel %d: decode socks4", c->self);
940 have = buffer_len(&c->input);
941 len = sizeof(s4_req);
944 p = buffer_ptr(&c->input);
945 for (found = 0, i = len; i < have; i++) {
951 /* the peer is probably sending garbage */
952 debug("channel %d: decode socks4: too long",
959 buffer_get(&c->input, (char *)&s4_req.version, 1);
960 buffer_get(&c->input, (char *)&s4_req.command, 1);
961 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
962 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
963 have = buffer_len(&c->input);
964 p = buffer_ptr(&c->input);
966 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
968 fatal("channel %d: decode socks4: len %d > have %d",
970 strlcpy(username, p, sizeof(username));
971 buffer_consume(&c->input, len);
972 buffer_consume(&c->input, 1); /* trailing '\0' */
974 host = inet_ntoa(s4_req.dest_addr);
975 strlcpy(c->path, host, sizeof(c->path));
976 c->host_port = ntohs(s4_req.dest_port);
978 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
979 c->self, host, c->host_port, s4_req.command);
981 if (s4_req.command != 1) {
982 debug("channel %d: cannot handle: socks4 cn %d",
983 c->self, s4_req.command);
986 s4_rsp.version = 0; /* vn: 0 for reply */
987 s4_rsp.command = 90; /* cd: req granted */
988 s4_rsp.dest_port = 0; /* ignored */
989 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
990 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
994 /* try to decode a socks5 header */
995 #define SSH_SOCKS5_AUTHDONE 0x1000
996 #define SSH_SOCKS5_NOAUTH 0x00
997 #define SSH_SOCKS5_IPV4 0x01
998 #define SSH_SOCKS5_DOMAIN 0x03
999 #define SSH_SOCKS5_IPV6 0x04
1000 #define SSH_SOCKS5_CONNECT 0x01
1001 #define SSH_SOCKS5_SUCCESS 0x00
1004 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1012 u_int16_t dest_port;
1013 u_char *p, dest_addr[255+1];
1014 u_int have, i, found, nmethods, addrlen, af;
1016 debug2("channel %d: decode socks5", c->self);
1017 p = buffer_ptr(&c->input);
1020 have = buffer_len(&c->input);
1021 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1022 /* format: ver | nmethods | methods */
1026 if (have < nmethods + 2)
1028 /* look for method: "NO AUTHENTICATION REQUIRED" */
1029 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
1030 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1036 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1040 buffer_consume(&c->input, nmethods + 2);
1041 buffer_put_char(&c->output, 0x05); /* version */
1042 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1043 FD_SET(c->sock, writeset);
1044 c->flags |= SSH_SOCKS5_AUTHDONE;
1045 debug2("channel %d: socks5 auth done", c->self);
1046 return 0; /* need more */
1048 debug2("channel %d: socks5 post auth", c->self);
1049 if (have < sizeof(s5_req)+1)
1050 return 0; /* need more */
1051 memcpy((char *)&s5_req, p, sizeof(s5_req));
1052 if (s5_req.version != 0x05 ||
1053 s5_req.command != SSH_SOCKS5_CONNECT ||
1054 s5_req.reserved != 0x00) {
1055 debug2("channel %d: only socks5 connect supported", c->self);
1058 switch (s5_req.atyp){
1059 case SSH_SOCKS5_IPV4:
1063 case SSH_SOCKS5_DOMAIN:
1064 addrlen = p[sizeof(s5_req)];
1067 case SSH_SOCKS5_IPV6:
1072 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1075 if (have < 4 + addrlen + 2)
1077 buffer_consume(&c->input, sizeof(s5_req));
1078 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1079 buffer_consume(&c->input, 1); /* host string length */
1080 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1081 buffer_get(&c->input, (char *)&dest_port, 2);
1082 dest_addr[addrlen] = '\0';
1083 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1084 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1085 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1087 c->host_port = ntohs(dest_port);
1089 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1090 c->self, c->path, c->host_port, s5_req.command);
1092 s5_rsp.version = 0x05;
1093 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1094 s5_rsp.reserved = 0; /* ignored */
1095 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1096 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1097 dest_port = 0; /* ignored */
1099 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1100 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1101 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1105 /* dynamic port forwarding */
1107 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1113 have = buffer_len(&c->input);
1115 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1116 /* buffer_dump(&c->input); */
1117 /* check if the fixed size part of the packet is in buffer. */
1120 FD_SET(c->sock, readset);
1123 /* try to guess the protocol */
1124 p = buffer_ptr(&c->input);
1127 ret = channel_decode_socks4(c, readset, writeset);
1130 ret = channel_decode_socks5(c, readset, writeset);
1138 } else if (ret == 0) {
1139 debug2("channel %d: pre_dynamic: need more", c->self);
1141 FD_SET(c->sock, readset);
1143 /* switch to the next state */
1144 c->type = SSH_CHANNEL_OPENING;
1145 port_open_helper(c, "direct-tcpip");
1149 /* This is our fake X11 server socket. */
1151 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1154 struct sockaddr addr;
1157 char buf[16384], *remote_ipaddr;
1160 if (FD_ISSET(c->sock, readset)) {
1161 debug("X11 connection requested.");
1162 addrlen = sizeof(addr);
1163 newsock = accept(c->sock, &addr, &addrlen);
1164 if (c->single_connection) {
1165 debug2("single_connection: closing X11 listener.");
1166 channel_close_fd(&c->sock);
1170 error("accept: %.100s", strerror(errno));
1173 set_nodelay(newsock);
1174 remote_ipaddr = get_peer_ipaddr(newsock);
1175 remote_port = get_peer_port(newsock);
1176 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1177 remote_ipaddr, remote_port);
1179 nc = channel_new("accepted x11 socket",
1180 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1181 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1183 packet_start(SSH2_MSG_CHANNEL_OPEN);
1184 packet_put_cstring("x11");
1185 packet_put_int(nc->self);
1186 packet_put_int(nc->local_window_max);
1187 packet_put_int(nc->local_maxpacket);
1188 /* originator ipaddr and port */
1189 packet_put_cstring(remote_ipaddr);
1190 if (datafellows & SSH_BUG_X11FWD) {
1191 debug2("ssh2 x11 bug compat mode");
1193 packet_put_int(remote_port);
1197 packet_start(SSH_SMSG_X11_OPEN);
1198 packet_put_int(nc->self);
1199 if (packet_get_protocol_flags() &
1200 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1201 packet_put_cstring(buf);
1204 xfree(remote_ipaddr);
1209 port_open_helper(Channel *c, char *rtype)
1213 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1214 int remote_port = get_peer_port(c->sock);
1216 direct = (strcmp(rtype, "direct-tcpip") == 0);
1218 snprintf(buf, sizeof buf,
1219 "%s: listening port %d for %.100s port %d, "
1220 "connect from %.200s port %d",
1221 rtype, c->listening_port, c->path, c->host_port,
1222 remote_ipaddr, remote_port);
1224 xfree(c->remote_name);
1225 c->remote_name = xstrdup(buf);
1228 packet_start(SSH2_MSG_CHANNEL_OPEN);
1229 packet_put_cstring(rtype);
1230 packet_put_int(c->self);
1231 packet_put_int(c->local_window_max);
1232 packet_put_int(c->local_maxpacket);
1234 /* target host, port */
1235 packet_put_cstring(c->path);
1236 packet_put_int(c->host_port);
1238 /* listen address, port */
1239 packet_put_cstring(c->path);
1240 packet_put_int(c->listening_port);
1242 /* originator host and port */
1243 packet_put_cstring(remote_ipaddr);
1244 packet_put_int((u_int)remote_port);
1247 packet_start(SSH_MSG_PORT_OPEN);
1248 packet_put_int(c->self);
1249 packet_put_cstring(c->path);
1250 packet_put_int(c->host_port);
1251 if (packet_get_protocol_flags() &
1252 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1253 packet_put_cstring(c->remote_name);
1256 xfree(remote_ipaddr);
1260 channel_set_reuseaddr(int fd)
1265 * Set socket options.
1266 * Allow local port reuse in TIME_WAIT.
1268 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1269 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1273 * This socket is listening for connections to a forwarded TCP/IP port.
1276 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1279 struct sockaddr addr;
1280 int newsock, nextstate;
1284 if (FD_ISSET(c->sock, readset)) {
1285 debug("Connection to port %d forwarding "
1286 "to %.100s port %d requested.",
1287 c->listening_port, c->path, c->host_port);
1289 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1290 nextstate = SSH_CHANNEL_OPENING;
1291 rtype = "forwarded-tcpip";
1293 if (c->host_port == 0) {
1294 nextstate = SSH_CHANNEL_DYNAMIC;
1295 rtype = "dynamic-tcpip";
1297 nextstate = SSH_CHANNEL_OPENING;
1298 rtype = "direct-tcpip";
1302 addrlen = sizeof(addr);
1303 newsock = accept(c->sock, &addr, &addrlen);
1305 error("accept: %.100s", strerror(errno));
1308 set_nodelay(newsock);
1309 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1310 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1311 nc->listening_port = c->listening_port;
1312 nc->host_port = c->host_port;
1313 strlcpy(nc->path, c->path, sizeof(nc->path));
1315 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1317 * do not call the channel_post handler until
1318 * this flag has been reset by a pre-handler.
1319 * otherwise the FD_ISSET calls might overflow
1323 port_open_helper(nc, rtype);
1329 * This is the authentication agent socket listening for connections from
1333 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1337 struct sockaddr addr;
1340 if (FD_ISSET(c->sock, readset)) {
1341 addrlen = sizeof(addr);
1342 newsock = accept(c->sock, &addr, &addrlen);
1344 error("accept from auth socket: %.100s", strerror(errno));
1347 nc = channel_new("accepted auth socket",
1348 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1349 c->local_window_max, c->local_maxpacket,
1350 0, "accepted auth socket", 1);
1352 packet_start(SSH2_MSG_CHANNEL_OPEN);
1353 packet_put_cstring("auth-agent@openssh.com");
1354 packet_put_int(nc->self);
1355 packet_put_int(c->local_window_max);
1356 packet_put_int(c->local_maxpacket);
1358 packet_start(SSH_SMSG_AGENT_OPEN);
1359 packet_put_int(nc->self);
1366 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1369 socklen_t sz = sizeof(err);
1371 if (FD_ISSET(c->sock, writeset)) {
1372 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1374 error("getsockopt SO_ERROR failed");
1377 debug("channel %d: connected", c->self);
1378 c->type = SSH_CHANNEL_OPEN;
1380 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1381 packet_put_int(c->remote_id);
1382 packet_put_int(c->self);
1383 packet_put_int(c->local_window);
1384 packet_put_int(c->local_maxpacket);
1386 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1387 packet_put_int(c->remote_id);
1388 packet_put_int(c->self);
1391 debug("channel %d: not connected: %s",
1392 c->self, strerror(err));
1394 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1395 packet_put_int(c->remote_id);
1396 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1397 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1398 packet_put_cstring(strerror(err));
1399 packet_put_cstring("");
1402 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1403 packet_put_int(c->remote_id);
1412 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1414 char buf[CHAN_RBUF];
1418 FD_ISSET(c->rfd, readset)) {
1419 len = read(c->rfd, buf, sizeof(buf));
1420 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1423 debug2("channel %d: read<=0 rfd %d len %d",
1424 c->self, c->rfd, len);
1425 if (c->type != SSH_CHANNEL_OPEN) {
1426 debug2("channel %d: not open", c->self);
1429 } else if (compat13) {
1430 buffer_clear(&c->output);
1431 c->type = SSH_CHANNEL_INPUT_DRAINING;
1432 debug2("channel %d: input draining.", c->self);
1434 chan_read_failed(c);
1438 if (c->input_filter != NULL) {
1439 if (c->input_filter(c, buf, len) == -1) {
1440 debug2("channel %d: filter stops", c->self);
1441 chan_read_failed(c);
1443 } else if (c->datagram) {
1444 buffer_put_string(&c->input, buf, len);
1446 buffer_append(&c->input, buf, len);
1453 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1456 u_char *data = NULL, *buf;
1460 /* Send buffered output data to the socket. */
1462 FD_ISSET(c->wfd, writeset) &&
1463 buffer_len(&c->output) > 0) {
1464 if (c->output_filter != NULL) {
1465 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1466 debug2("channel %d: filter stops", c->self);
1467 if (c->type != SSH_CHANNEL_OPEN)
1470 chan_write_failed(c);
1473 } else if (c->datagram) {
1474 buf = data = buffer_get_string(&c->output, &dlen);
1476 buf = data = buffer_ptr(&c->output);
1477 dlen = buffer_len(&c->output);
1481 /* ignore truncated writes, datagrams might get lost */
1482 c->local_consumed += dlen + 4;
1483 len = write(c->wfd, buf, dlen);
1485 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1488 if (c->type != SSH_CHANNEL_OPEN)
1491 chan_write_failed(c);
1497 /* XXX: Later AIX versions can't push as much data to tty */
1498 if (compat20 && c->wfd_isatty)
1499 dlen = MIN(dlen, 8*1024);
1502 len = write(c->wfd, buf, dlen);
1503 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1506 if (c->type != SSH_CHANNEL_OPEN) {
1507 debug2("channel %d: not open", c->self);
1510 } else if (compat13) {
1511 buffer_clear(&c->output);
1512 debug2("channel %d: input draining.", c->self);
1513 c->type = SSH_CHANNEL_INPUT_DRAINING;
1515 chan_write_failed(c);
1519 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1520 if (tcgetattr(c->wfd, &tio) == 0 &&
1521 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1523 * Simulate echo to reduce the impact of
1524 * traffic analysis. We need to match the
1525 * size of a SSH2_MSG_CHANNEL_DATA message
1526 * (4 byte channel id + buf)
1528 packet_send_ignore(4 + len);
1532 buffer_consume(&c->output, len);
1533 if (compat20 && len > 0) {
1534 c->local_consumed += len;
1541 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1543 char buf[CHAN_RBUF];
1546 /** XXX handle drain efd, too */
1548 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1549 FD_ISSET(c->efd, writeset) &&
1550 buffer_len(&c->extended) > 0) {
1551 len = write(c->efd, buffer_ptr(&c->extended),
1552 buffer_len(&c->extended));
1553 debug2("channel %d: written %d to efd %d",
1554 c->self, len, c->efd);
1555 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1558 debug2("channel %d: closing write-efd %d",
1560 channel_close_fd(&c->efd);
1562 buffer_consume(&c->extended, len);
1563 c->local_consumed += len;
1565 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1566 FD_ISSET(c->efd, readset)) {
1567 len = read(c->efd, buf, sizeof(buf));
1568 debug2("channel %d: read %d from efd %d",
1569 c->self, len, c->efd);
1570 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1573 debug2("channel %d: closing read-efd %d",
1575 channel_close_fd(&c->efd);
1577 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__);
1613 channel_check_window(Channel *c)
1615 if (c->type == SSH_CHANNEL_OPEN &&
1616 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1617 c->local_window < c->local_window_max/2 &&
1618 c->local_consumed > 0) {
1619 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1620 packet_put_int(c->remote_id);
1621 packet_put_int(c->local_consumed);
1623 debug2("channel %d: window %d sent adjust %d",
1624 c->self, c->local_window,
1626 c->local_window += c->local_consumed;
1627 c->local_consumed = 0;
1633 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1637 channel_handle_rfd(c, readset, writeset);
1638 channel_handle_wfd(c, readset, writeset);
1641 channel_handle_efd(c, readset, writeset);
1642 channel_handle_ctl(c, readset, writeset);
1643 channel_check_window(c);
1647 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1651 /* Send buffered output data to the socket. */
1652 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1653 len = write(c->sock, buffer_ptr(&c->output),
1654 buffer_len(&c->output));
1656 buffer_clear(&c->output);
1658 buffer_consume(&c->output, len);
1663 channel_handler_init_20(void)
1665 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1666 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1667 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1668 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1669 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1670 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1671 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1672 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1674 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1675 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1676 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1677 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1678 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1679 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1680 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1684 channel_handler_init_13(void)
1686 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1687 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1688 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1689 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1690 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1691 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1692 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1693 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1694 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1696 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1697 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1698 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1699 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1700 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1701 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1702 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1706 channel_handler_init_15(void)
1708 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1709 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1710 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1711 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1712 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1713 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1714 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1716 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1717 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1718 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1719 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1720 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1721 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1725 channel_handler_init(void)
1729 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1730 channel_pre[i] = NULL;
1731 channel_post[i] = NULL;
1734 channel_handler_init_20();
1736 channel_handler_init_13();
1738 channel_handler_init_15();
1741 /* gc dead channels */
1743 channel_garbage_collect(Channel *c)
1747 if (c->detach_user != NULL) {
1748 if (!chan_is_dead(c, c->detach_close))
1750 debug2("channel %d: gc: notify user", c->self);
1751 c->detach_user(c->self, NULL);
1752 /* if we still have a callback */
1753 if (c->detach_user != NULL)
1755 debug2("channel %d: gc: user detached", c->self);
1757 if (!chan_is_dead(c, 1))
1759 debug2("channel %d: garbage collecting", c->self);
1764 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1766 static int did_init = 0;
1771 channel_handler_init();
1774 for (i = 0; i < channels_alloc; i++) {
1778 if (ftab[c->type] != NULL)
1779 (*ftab[c->type])(c, readset, writeset);
1780 channel_garbage_collect(c);
1785 * Allocate/update select bitmasks and add any bits relevant to channels in
1789 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1790 u_int *nallocp, int rekeying)
1794 n = MAX(*maxfdp, channel_max_fd);
1796 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1797 /* perhaps check sz < nalloc/2 and shrink? */
1798 if (*readsetp == NULL || sz > *nallocp) {
1799 *readsetp = xrealloc(*readsetp, sz);
1800 *writesetp = xrealloc(*writesetp, sz);
1804 memset(*readsetp, 0, sz);
1805 memset(*writesetp, 0, sz);
1808 channel_handler(channel_pre, *readsetp, *writesetp);
1812 * After select, perform any appropriate operations for channels which have
1816 channel_after_select(fd_set *readset, fd_set *writeset)
1818 channel_handler(channel_post, readset, writeset);
1822 /* 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 */
1943 channel_input_data(int type, u_int32_t seq, void *ctxt)
1950 /* Get the channel number and verify it. */
1951 id = packet_get_int();
1952 c = channel_lookup(id);
1954 packet_disconnect("Received data for nonexistent channel %d.", id);
1956 /* Ignore any data for non-open channels (might happen on close) */
1957 if (c->type != SSH_CHANNEL_OPEN &&
1958 c->type != SSH_CHANNEL_X11_OPEN)
1962 data = packet_get_string(&data_len);
1965 * Ignore data for protocol > 1.3 if output end is no longer open.
1966 * For protocol 2 the sending side is reducing its window as it sends
1967 * data, so we must 'fake' consumption of the data in order to ensure
1968 * that window updates are sent back. Otherwise the connection might
1971 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1973 c->local_window -= data_len;
1974 c->local_consumed += data_len;
1981 if (data_len > c->local_maxpacket) {
1982 logit("channel %d: rcvd big packet %d, maxpack %d",
1983 c->self, data_len, c->local_maxpacket);
1985 if (data_len > c->local_window) {
1986 logit("channel %d: rcvd too much data %d, win %d",
1987 c->self, data_len, c->local_window);
1991 c->local_window -= data_len;
1995 buffer_put_string(&c->output, data, data_len);
1997 buffer_append(&c->output, data, data_len);
2002 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2006 u_int data_len, tcode;
2009 /* Get the channel number and verify it. */
2010 id = packet_get_int();
2011 c = channel_lookup(id);
2014 packet_disconnect("Received extended_data for bad channel %d.", id);
2015 if (c->type != SSH_CHANNEL_OPEN) {
2016 logit("channel %d: ext data for non open", id);
2019 if (c->flags & CHAN_EOF_RCVD) {
2020 if (datafellows & SSH_BUG_EXTEOF)
2021 debug("channel %d: accepting ext data after eof", id);
2023 packet_disconnect("Received extended_data after EOF "
2024 "on channel %d.", id);
2026 tcode = packet_get_int();
2028 c->extended_usage != CHAN_EXTENDED_WRITE ||
2029 tcode != SSH2_EXTENDED_DATA_STDERR) {
2030 logit("channel %d: bad ext data", c->self);
2033 data = packet_get_string(&data_len);
2035 if (data_len > c->local_window) {
2036 logit("channel %d: rcvd too much extended_data %d, win %d",
2037 c->self, data_len, c->local_window);
2041 debug2("channel %d: rcvd ext data %d", c->self, data_len);
2042 c->local_window -= data_len;
2043 buffer_append(&c->extended, data, data_len);
2048 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2053 id = packet_get_int();
2055 c = channel_lookup(id);
2057 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2060 /* XXX force input close */
2061 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2062 debug("channel %d: FORCE input drain", c->self);
2063 c->istate = CHAN_INPUT_WAIT_DRAIN;
2064 if (buffer_len(&c->input) == 0)
2071 channel_input_close(int type, u_int32_t seq, void *ctxt)
2076 id = packet_get_int();
2078 c = channel_lookup(id);
2080 packet_disconnect("Received close for nonexistent channel %d.", id);
2083 * Send a confirmation that we have closed the channel and no more
2084 * data is coming for it.
2086 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2087 packet_put_int(c->remote_id);
2091 * If the channel is in closed state, we have sent a close request,
2092 * and the other side will eventually respond with a confirmation.
2093 * Thus, we cannot free the channel here, because then there would be
2094 * no-one to receive the confirmation. The channel gets freed when
2095 * the confirmation arrives.
2097 if (c->type != SSH_CHANNEL_CLOSED) {
2099 * Not a closed channel - mark it as draining, which will
2100 * cause it to be freed later.
2102 buffer_clear(&c->input);
2103 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2107 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2109 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2111 int id = packet_get_int();
2112 Channel *c = channel_lookup(id);
2116 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2117 chan_rcvd_oclose(c);
2121 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2123 int id = packet_get_int();
2124 Channel *c = channel_lookup(id);
2128 packet_disconnect("Received close confirmation for "
2129 "out-of-range channel %d.", id);
2130 if (c->type != SSH_CHANNEL_CLOSED)
2131 packet_disconnect("Received close confirmation for "
2132 "non-closed channel %d (type %d).", id, c->type);
2137 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2142 id = packet_get_int();
2143 c = channel_lookup(id);
2145 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2146 packet_disconnect("Received open confirmation for "
2147 "non-opening channel %d.", id);
2148 remote_id = packet_get_int();
2149 /* Record the remote channel number and mark that the channel is now open. */
2150 c->remote_id = remote_id;
2151 c->type = SSH_CHANNEL_OPEN;
2154 c->remote_window = packet_get_int();
2155 c->remote_maxpacket = packet_get_int();
2157 debug2("callback start");
2158 c->confirm(c->self, c->confirm_ctx);
2159 debug2("callback done");
2161 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2162 c->remote_window, c->remote_maxpacket);
2168 reason2txt(int reason)
2171 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2172 return "administratively prohibited";
2173 case SSH2_OPEN_CONNECT_FAILED:
2174 return "connect failed";
2175 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2176 return "unknown channel type";
2177 case SSH2_OPEN_RESOURCE_SHORTAGE:
2178 return "resource shortage";
2180 return "unknown reason";
2184 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2187 char *msg = NULL, *lang = NULL;
2190 id = packet_get_int();
2191 c = channel_lookup(id);
2193 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2194 packet_disconnect("Received open failure for "
2195 "non-opening channel %d.", id);
2197 reason = packet_get_int();
2198 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2199 msg = packet_get_string(NULL);
2200 lang = packet_get_string(NULL);
2202 logit("channel %d: open failed: %s%s%s", id,
2203 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2210 /* Free the channel. This will also close the socket. */
2215 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2224 /* Get the channel number and verify it. */
2225 id = packet_get_int();
2226 c = channel_lookup(id);
2229 logit("Received window adjust for non-open channel %d.", id);
2232 adjust = packet_get_int();
2234 debug2("channel %d: rcvd adjust %u", id, adjust);
2235 c->remote_window += adjust;
2239 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2243 char *host, *originator_string;
2244 int remote_id, sock = -1;
2246 remote_id = packet_get_int();
2247 host = packet_get_string(NULL);
2248 host_port = packet_get_int();
2250 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2251 originator_string = packet_get_string(NULL);
2253 originator_string = xstrdup("unknown (remote did not supply name)");
2256 sock = channel_connect_to(host, host_port);
2258 c = channel_new("connected socket",
2259 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2260 originator_string, 1);
2261 c->remote_id = remote_id;
2263 xfree(originator_string);
2265 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2266 packet_put_int(remote_id);
2273 /* -- tcp forwarding */
2276 channel_set_af(int af)
2282 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2283 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2286 int sock, r, success = 0, wildcard = 0, is_client;
2287 struct addrinfo hints, *ai, *aitop;
2288 const char *host, *addr;
2289 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2291 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2292 listen_addr : host_to_connect;
2293 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2296 error("No forward host name.");
2299 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2300 error("Forward host name too long.");
2305 * Determine whether or not a port forward listens to loopback,
2306 * specified address or wildcard. On the client, a specified bind
2307 * address will always override gateway_ports. On the server, a
2308 * gateway_ports of 1 (``yes'') will override the client's
2309 * specification and force a wildcard bind, whereas a value of 2
2310 * (``clientspecified'') will bind to whatever address the client
2313 * Special-case listen_addrs are:
2315 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2316 * "" (empty string), "*" -> wildcard v4/v6
2317 * "localhost" -> loopback v4/v6
2320 if (listen_addr == NULL) {
2321 /* No address specified: default to gateway_ports setting */
2324 } else if (gateway_ports || is_client) {
2325 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2326 strcmp(listen_addr, "0.0.0.0") == 0) ||
2327 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2328 (!is_client && gateway_ports == 1))
2330 else if (strcmp(listen_addr, "localhost") != 0)
2334 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2335 type, wildcard, (addr == NULL) ? "NULL" : addr);
2338 * getaddrinfo returns a loopback address if the hostname is
2339 * set to NULL and hints.ai_flags is not AI_PASSIVE
2341 memset(&hints, 0, sizeof(hints));
2342 hints.ai_family = IPv4or6;
2343 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2344 hints.ai_socktype = SOCK_STREAM;
2345 snprintf(strport, sizeof strport, "%d", listen_port);
2346 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2348 /* This really shouldn't happen */
2349 packet_disconnect("getaddrinfo: fatal error: %s",
2352 error("channel_setup_fwd_listener: "
2353 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2358 for (ai = aitop; ai; ai = ai->ai_next) {
2359 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2361 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2362 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2363 error("channel_setup_fwd_listener: getnameinfo failed");
2366 /* Create a port to listen for the host. */
2367 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2369 /* this is no error since kernel may not support ipv6 */
2370 verbose("socket: %.100s", strerror(errno));
2374 channel_set_reuseaddr(sock);
2376 debug("Local forwarding listening on %s port %s.", ntop, strport);
2378 /* Bind the socket to the address. */
2379 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2380 /* address can be in use ipv6 address is already bound */
2382 error("bind: %.100s", strerror(errno));
2384 verbose("bind: %.100s", strerror(errno));
2389 /* Start listening for connections on the socket. */
2390 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2391 error("listen: %.100s", strerror(errno));
2395 /* Allocate a channel number for the socket. */
2396 c = channel_new("port listener", type, sock, sock, -1,
2397 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2398 0, "port listener", 1);
2399 strlcpy(c->path, host, sizeof(c->path));
2400 c->host_port = port_to_connect;
2401 c->listening_port = listen_port;
2405 error("channel_setup_fwd_listener: cannot listen to port: %d",
2407 freeaddrinfo(aitop);
2412 channel_cancel_rport_listener(const char *host, u_short port)
2417 for (i = 0; i < channels_alloc; i++) {
2418 Channel *c = channels[i];
2420 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2421 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2422 c->listening_port == port) {
2423 debug2("%s: close channel %d", __func__, i);
2432 /* protocol local port fwd, used by ssh (and sshd in v1) */
2434 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2435 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2437 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2438 listen_host, listen_port, host_to_connect, port_to_connect,
2442 /* protocol v2 remote port fwd, used by sshd */
2444 channel_setup_remote_fwd_listener(const char *listen_address,
2445 u_short listen_port, int gateway_ports)
2447 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2448 listen_address, listen_port, NULL, 0, gateway_ports);
2452 * Initiate forwarding of connections to port "port" on remote host through
2453 * the secure channel to host:port from local side.
2457 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2458 const char *host_to_connect, u_short port_to_connect)
2460 int type, success = 0;
2462 /* Record locally that connection to this host/port is permitted. */
2463 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2464 fatal("channel_request_remote_forwarding: too many forwards");
2466 /* Send the forward request to the remote side. */
2468 const char *address_to_bind;
2469 if (listen_host == NULL)
2470 address_to_bind = "localhost";
2471 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2472 address_to_bind = "";
2474 address_to_bind = listen_host;
2476 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2477 packet_put_cstring("tcpip-forward");
2478 packet_put_char(1); /* boolean: want reply */
2479 packet_put_cstring(address_to_bind);
2480 packet_put_int(listen_port);
2482 packet_write_wait();
2483 /* Assume that server accepts the request */
2486 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2487 packet_put_int(listen_port);
2488 packet_put_cstring(host_to_connect);
2489 packet_put_int(port_to_connect);
2491 packet_write_wait();
2493 /* Wait for response from the remote side. */
2494 type = packet_read();
2496 case SSH_SMSG_SUCCESS:
2499 case SSH_SMSG_FAILURE:
2500 logit("Warning: Server denied remote port forwarding.");
2503 /* Unknown packet */
2504 packet_disconnect("Protocol error for port forward request:"
2505 "received packet type %d.", type);
2509 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2510 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2511 permitted_opens[num_permitted_opens].listen_port = listen_port;
2512 num_permitted_opens++;
2517 * Request cancellation of remote forwarding of connection host:port from
2521 channel_request_rforward_cancel(const char *host, u_short port)
2528 for (i = 0; i < num_permitted_opens; i++) {
2529 if (permitted_opens[i].host_to_connect != NULL &&
2530 permitted_opens[i].listen_port == port)
2533 if (i >= num_permitted_opens) {
2534 debug("%s: requested forward not found", __func__);
2537 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2538 packet_put_cstring("cancel-tcpip-forward");
2540 packet_put_cstring(host == NULL ? "" : host);
2541 packet_put_int(port);
2544 permitted_opens[i].listen_port = 0;
2545 permitted_opens[i].port_to_connect = 0;
2546 xfree(permitted_opens[i].host_to_connect);
2547 permitted_opens[i].host_to_connect = NULL;
2551 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2552 * listening for the port, and sends back a success reply (or disconnect
2553 * message if there was an error). This never returns if there was an error.
2556 channel_input_port_forward_request(int is_root, int gateway_ports)
2558 u_short port, host_port;
2561 /* Get arguments from the packet. */
2562 port = packet_get_int();
2563 hostname = packet_get_string(NULL);
2564 host_port = packet_get_int();
2568 * Check that an unprivileged user is not trying to forward a
2571 if (port < IPPORT_RESERVED && !is_root)
2573 "Requested forwarding of port %d but user is not root.",
2576 packet_disconnect("Dynamic forwarding denied.");
2579 /* Initiate forwarding */
2580 channel_setup_local_fwd_listener(NULL, port, hostname,
2581 host_port, gateway_ports);
2583 /* Free the argument string. */
2588 * Permits opening to any host/port if permitted_opens[] is empty. This is
2589 * usually called by the server, because the user could connect to any port
2590 * anyway, and the server has no way to know but to trust the client anyway.
2593 channel_permit_all_opens(void)
2595 if (num_permitted_opens == 0)
2596 all_opens_permitted = 1;
2600 channel_add_permitted_opens(char *host, int port)
2602 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2603 fatal("channel_request_remote_forwarding: too many forwards");
2604 debug("allow port forwarding to host %s port %d", host, port);
2606 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2607 permitted_opens[num_permitted_opens].port_to_connect = port;
2608 num_permitted_opens++;
2610 all_opens_permitted = 0;
2614 channel_clear_permitted_opens(void)
2618 for (i = 0; i < num_permitted_opens; i++)
2619 if (permitted_opens[i].host_to_connect != NULL)
2620 xfree(permitted_opens[i].host_to_connect);
2621 num_permitted_opens = 0;
2625 /* return socket to remote host, port */
2627 connect_to(const char *host, u_short port)
2629 struct addrinfo hints, *ai, *aitop;
2630 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2634 memset(&hints, 0, sizeof(hints));
2635 hints.ai_family = IPv4or6;
2636 hints.ai_socktype = SOCK_STREAM;
2637 snprintf(strport, sizeof strport, "%d", port);
2638 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2639 error("connect_to %.100s: unknown host (%s)", host,
2640 gai_strerror(gaierr));
2643 for (ai = aitop; ai; ai = ai->ai_next) {
2644 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2646 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2647 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2648 error("connect_to: getnameinfo failed");
2651 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2653 if (ai->ai_next == NULL)
2654 error("socket: %.100s", strerror(errno));
2656 verbose("socket: %.100s", strerror(errno));
2659 if (set_nonblock(sock) == -1)
2660 fatal("%s: set_nonblock(%d)", __func__, sock);
2661 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2662 errno != EINPROGRESS) {
2663 error("connect_to %.100s port %s: %.100s", ntop, strport,
2666 continue; /* fail -- try next */
2668 break; /* success */
2671 freeaddrinfo(aitop);
2673 error("connect_to %.100s port %d: failed.", host, port);
2682 channel_connect_by_listen_address(u_short listen_port)
2686 for (i = 0; i < num_permitted_opens; i++)
2687 if (permitted_opens[i].host_to_connect != NULL &&
2688 permitted_opens[i].listen_port == listen_port)
2690 permitted_opens[i].host_to_connect,
2691 permitted_opens[i].port_to_connect);
2692 error("WARNING: Server requests forwarding for unknown listen_port %d",
2697 /* Check if connecting to that port is permitted and connect. */
2699 channel_connect_to(const char *host, u_short port)
2703 permit = all_opens_permitted;
2705 for (i = 0; i < num_permitted_opens; i++)
2706 if (permitted_opens[i].host_to_connect != NULL &&
2707 permitted_opens[i].port_to_connect == port &&
2708 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2713 logit("Received request to connect to host %.100s port %d, "
2714 "but the request was denied.", host, port);
2717 return connect_to(host, port);
2721 channel_send_window_changes(void)
2726 for (i = 0; i < channels_alloc; i++) {
2727 if (channels[i] == NULL || !channels[i]->client_tty ||
2728 channels[i]->type != SSH_CHANNEL_OPEN)
2730 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2732 channel_request_start(i, "window-change", 0);
2733 packet_put_int((u_int)ws.ws_col);
2734 packet_put_int((u_int)ws.ws_row);
2735 packet_put_int((u_int)ws.ws_xpixel);
2736 packet_put_int((u_int)ws.ws_ypixel);
2741 /* -- X11 forwarding */
2744 * Creates an internet domain socket for listening for X11 connections.
2745 * Returns 0 and a suitable display number for the DISPLAY variable
2746 * stored in display_numberp , or -1 if an error occurs.
2749 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2750 int single_connection, u_int *display_numberp, int **chanids)
2753 int display_number, sock;
2755 struct addrinfo hints, *ai, *aitop;
2756 char strport[NI_MAXSERV];
2757 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2759 if (chanids == NULL)
2762 for (display_number = x11_display_offset;
2763 display_number < MAX_DISPLAYS;
2765 port = 6000 + display_number;
2766 memset(&hints, 0, sizeof(hints));
2767 hints.ai_family = IPv4or6;
2768 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2769 hints.ai_socktype = SOCK_STREAM;
2770 snprintf(strport, sizeof strport, "%d", port);
2771 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2772 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2775 for (ai = aitop; ai; ai = ai->ai_next) {
2776 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2778 sock = socket(ai->ai_family, ai->ai_socktype,
2781 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2782 error("socket: %.100s", strerror(errno));
2783 freeaddrinfo(aitop);
2786 debug("x11_create_display_inet: Socket family %d not supported",
2792 if (ai->ai_family == AF_INET6) {
2794 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2795 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2798 channel_set_reuseaddr(sock);
2799 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2800 debug2("bind port %d: %.100s", port, strerror(errno));
2806 for (n = 0; n < num_socks; n++) {
2812 socks[num_socks++] = sock;
2813 #ifndef DONT_TRY_OTHER_AF
2814 if (num_socks == NUM_SOCKS)
2817 if (x11_use_localhost) {
2818 if (num_socks == NUM_SOCKS)
2825 freeaddrinfo(aitop);
2829 if (display_number >= MAX_DISPLAYS) {
2830 error("Failed to allocate internet-domain X11 display socket.");
2833 /* Start listening for connections on the socket. */
2834 for (n = 0; n < num_socks; n++) {
2836 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2837 error("listen: %.100s", strerror(errno));
2843 /* Allocate a channel for each socket. */
2844 *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
2845 for (n = 0; n < num_socks; n++) {
2847 nc = channel_new("x11 listener",
2848 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2849 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2850 0, "X11 inet listener", 1);
2851 nc->single_connection = single_connection;
2852 (*chanids)[n] = nc->self;
2856 /* Return the display number for the DISPLAY environment variable. */
2857 *display_numberp = display_number;
2862 connect_local_xsocket(u_int dnr)
2865 struct sockaddr_un addr;
2867 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2869 error("socket: %.100s", strerror(errno));
2870 memset(&addr, 0, sizeof(addr));
2871 addr.sun_family = AF_UNIX;
2872 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2873 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
2876 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2881 x11_connect_display(void)
2883 int display_number, sock = 0;
2884 const char *display;
2885 char buf[1024], *cp;
2886 struct addrinfo hints, *ai, *aitop;
2887 char strport[NI_MAXSERV];
2890 /* Try to open a socket for the local X server. */
2891 display = getenv("DISPLAY");
2893 error("DISPLAY not set.");
2897 * Now we decode the value of the DISPLAY variable and make a
2898 * connection to the real X server.
2902 * Check if it is a unix domain socket. Unix domain displays are in
2903 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2905 if (strncmp(display, "unix:", 5) == 0 ||
2906 display[0] == ':') {
2907 /* Connect to the unix domain socket. */
2908 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2909 error("Could not parse display number from DISPLAY: %.100s",
2913 /* Create a socket. */
2914 sock = connect_local_xsocket(display_number);
2918 /* OK, we now have a connection to the display. */
2922 * Connect to an inet socket. The DISPLAY value is supposedly
2923 * hostname:d[.s], where hostname may also be numeric IP address.
2925 strlcpy(buf, display, sizeof(buf));
2926 cp = strchr(buf, ':');
2928 error("Could not find ':' in DISPLAY: %.100s", display);
2932 /* buf now contains the host name. But first we parse the display number. */
2933 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2934 error("Could not parse display number from DISPLAY: %.100s",
2939 /* Look up the host address */
2940 memset(&hints, 0, sizeof(hints));
2941 hints.ai_family = IPv4or6;
2942 hints.ai_socktype = SOCK_STREAM;
2943 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2944 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2945 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2948 for (ai = aitop; ai; ai = ai->ai_next) {
2949 /* Create a socket. */
2950 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2952 debug2("socket: %.100s", strerror(errno));
2955 /* Connect it to the display. */
2956 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2957 debug2("connect %.100s port %d: %.100s", buf,
2958 6000 + display_number, strerror(errno));
2965 freeaddrinfo(aitop);
2967 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2976 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2977 * the remote channel number. We should do whatever we want, and respond
2978 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2982 x11_input_open(int type, u_int32_t seq, void *ctxt)
2985 int remote_id, sock = 0;
2988 debug("Received X11 open request.");
2990 remote_id = packet_get_int();
2992 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2993 remote_host = packet_get_string(NULL);
2995 remote_host = xstrdup("unknown (remote did not supply name)");
2999 /* Obtain a connection to the real X display. */
3000 sock = x11_connect_display();
3002 /* Allocate a channel for this connection. */
3003 c = channel_new("connected x11 socket",
3004 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3006 c->remote_id = remote_id;
3011 /* Send refusal to the remote host. */
3012 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3013 packet_put_int(remote_id);
3015 /* Send a confirmation to the remote host. */
3016 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3017 packet_put_int(remote_id);
3018 packet_put_int(c->self);
3023 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3025 deny_input_open(int type, u_int32_t seq, void *ctxt)
3027 int rchan = packet_get_int();
3030 case SSH_SMSG_AGENT_OPEN:
3031 error("Warning: ssh server tried agent forwarding.");
3033 case SSH_SMSG_X11_OPEN:
3034 error("Warning: ssh server tried X11 forwarding.");
3037 error("deny_input_open: type %d", type);
3040 error("Warning: this is probably a break-in attempt by a malicious server.");
3041 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3042 packet_put_int(rchan);
3047 * Requests forwarding of X11 connections, generates fake authentication
3048 * data, and enables authentication spoofing.
3049 * This should be called in the client only.
3052 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3053 const char *proto, const char *data)
3055 u_int data_len = (u_int) strlen(data) / 2;
3062 if (x11_saved_display == NULL)
3063 x11_saved_display = xstrdup(disp);
3064 else if (strcmp(disp, x11_saved_display) != 0) {
3065 error("x11_request_forwarding_with_spoofing: different "
3066 "$DISPLAY already forwarded");
3072 cp = strchr(disp, ':');
3074 cp = strchr(cp, '.');
3076 screen_number = atoi(cp + 1);
3080 if (x11_saved_proto == NULL) {
3081 /* Save protocol name. */
3082 x11_saved_proto = xstrdup(proto);
3084 * Extract real authentication data and generate fake data
3085 * of the same length.
3087 x11_saved_data = xmalloc(data_len);
3088 x11_fake_data = xmalloc(data_len);
3089 for (i = 0; i < data_len; i++) {
3090 if (sscanf(data + 2 * i, "%2x", &value) != 1)
3091 fatal("x11_request_forwarding: bad "
3092 "authentication data: %.100s", data);
3095 x11_saved_data[i] = value;
3096 x11_fake_data[i] = rnd & 0xff;
3099 x11_saved_data_len = data_len;
3100 x11_fake_data_len = data_len;
3103 /* Convert the fake data into hex. */
3104 new_data = tohex(x11_fake_data, data_len);
3106 /* Send the request packet. */
3108 channel_request_start(client_session_id, "x11-req", 0);
3109 packet_put_char(0); /* XXX bool single connection */
3111 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3113 packet_put_cstring(proto);
3114 packet_put_cstring(new_data);
3115 packet_put_int(screen_number);
3117 packet_write_wait();
3122 /* -- agent forwarding */
3124 /* Sends a message to the server to request authentication fd forwarding. */
3127 auth_request_forwarding(void)
3129 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3131 packet_write_wait();