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 1.218 2005/07/01 13:19:47 markus Exp $");
56 #include "pathnames.h"
61 #define CHAN_RBUF 16*1024
64 * Pointer to an array containing all allocated channels. The array is
65 * dynamically extended as needed.
67 static Channel **channels = NULL;
70 * Size of the channel array. All slots of the array must always be
71 * initialized (at least the type field); unused slots set to NULL
73 static u_int channels_alloc = 0;
76 * Maximum file descriptor value used in any of the channels. This is
77 * updated in channel_new.
79 static int channel_max_fd = 0;
82 /* -- tcp forwarding */
85 * Data structure for storing which hosts are permitted for forward requests.
86 * The local sides of any remote forwards are stored in this array to prevent
87 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
88 * network (which might be behind a firewall).
91 char *host_to_connect; /* Connect to 'host'. */
92 u_short port_to_connect; /* Connect to 'port'. */
93 u_short listen_port; /* Remote side should listen port number. */
96 /* List of all permitted host/port pairs to connect. */
97 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
99 /* Number of permitted host/port pairs in the array. */
100 static int num_permitted_opens = 0;
102 * If this is true, all opens are permitted. This is the case on the server
103 * on which we have to trust the client anyway, and the user could do
104 * anything after logging in anyway.
106 static int all_opens_permitted = 0;
109 /* -- X11 forwarding */
111 /* Maximum number of fake X11 displays to try. */
112 #define MAX_DISPLAYS 1000
114 /* Saved X11 authentication protocol name. */
115 static char *x11_saved_proto = NULL;
117 /* Saved X11 authentication data. This is the real data. */
118 static char *x11_saved_data = NULL;
119 static u_int x11_saved_data_len = 0;
122 * Fake X11 authentication data. This is what the server will be sending us;
123 * we should replace any occurrences of this by the real data.
125 static char *x11_fake_data = NULL;
126 static u_int x11_fake_data_len;
129 /* -- agent forwarding */
133 /* AF_UNSPEC or AF_INET or AF_INET6 */
134 static int IPv4or6 = AF_UNSPEC;
137 static void port_open_helper(Channel *c, char *rtype);
139 /* -- channel core */
142 channel_lookup(int id)
146 if (id < 0 || (u_int)id >= channels_alloc) {
147 logit("channel_lookup: %d: bad id", id);
152 logit("channel_lookup: %d: bad id: channel free", id);
159 * Register filedescriptors for a channel, used when allocating a channel or
160 * when the channel consumer/producer is ready, e.g. shell exec'd
164 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
165 int extusage, int nonblock)
167 /* Update the maximum file descriptor value. */
168 channel_max_fd = MAX(channel_max_fd, rfd);
169 channel_max_fd = MAX(channel_max_fd, wfd);
170 channel_max_fd = MAX(channel_max_fd, efd);
172 /* XXX set close-on-exec -markus */
176 c->sock = (rfd == wfd) ? rfd : -1;
177 c->ctl_fd = -1; /* XXX: set elsewhere */
179 c->extended_usage = extusage;
181 /* XXX ugly hack: nonblock is only set by the server */
182 if (nonblock && isatty(c->rfd)) {
183 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
185 if (!isatty(c->wfd)) {
186 error("channel %d: wfd %d is not a tty?",
192 c->wfd_isatty = isatty(c->wfd);
194 /* enable nonblocking mode */
206 * Allocate a new channel object and set its type and socket. This will cause
207 * remote_name to be freed.
211 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
212 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
218 /* Do initial allocation if this is the first call. */
219 if (channels_alloc == 0) {
221 channels = xmalloc(channels_alloc * sizeof(Channel *));
222 for (i = 0; i < channels_alloc; i++)
225 /* Try to find a free slot where to put the new channel. */
226 for (found = -1, i = 0; i < channels_alloc; i++)
227 if (channels[i] == NULL) {
228 /* Found a free slot. */
233 /* There are no free slots. Take last+1 slot and expand the array. */
234 found = channels_alloc;
235 if (channels_alloc > 10000)
236 fatal("channel_new: internal error: channels_alloc %d "
237 "too big.", channels_alloc);
238 channels = xrealloc(channels,
239 (channels_alloc + 10) * sizeof(Channel *));
240 channels_alloc += 10;
241 debug2("channel: expanding %d", channels_alloc);
242 for (i = found; i < channels_alloc; i++)
245 /* Initialize and return new channel. */
246 c = channels[found] = xmalloc(sizeof(Channel));
247 memset(c, 0, sizeof(Channel));
248 buffer_init(&c->input);
249 buffer_init(&c->output);
250 buffer_init(&c->extended);
251 c->ostate = CHAN_OUTPUT_OPEN;
252 c->istate = CHAN_INPUT_OPEN;
254 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
258 c->local_window = window;
259 c->local_window_max = window;
260 c->local_consumed = 0;
261 c->local_maxpacket = maxpack;
263 c->remote_name = xstrdup(remote_name);
264 c->remote_window = 0;
265 c->remote_maxpacket = 0;
267 c->single_connection = 0;
268 c->detach_user = NULL;
270 c->confirm_ctx = NULL;
271 c->input_filter = NULL;
272 debug("channel %d: new [%s]", found, remote_name);
277 channel_find_maxfd(void)
283 for (i = 0; i < channels_alloc; i++) {
286 max = MAX(max, c->rfd);
287 max = MAX(max, c->wfd);
288 max = MAX(max, c->efd);
295 channel_close_fd(int *fdp)
297 int ret = 0, fd = *fdp;
302 if (fd == channel_max_fd)
303 channel_max_fd = channel_find_maxfd();
308 /* Close all channel fd/socket. */
311 channel_close_fds(Channel *c)
313 debug3("channel %d: close_fds r %d w %d e %d c %d",
314 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
316 channel_close_fd(&c->sock);
317 channel_close_fd(&c->ctl_fd);
318 channel_close_fd(&c->rfd);
319 channel_close_fd(&c->wfd);
320 channel_close_fd(&c->efd);
323 /* Free the channel and close its fd/socket. */
326 channel_free(Channel *c)
331 for (n = 0, i = 0; i < channels_alloc; i++)
334 debug("channel %d: free: %s, nchannels %u", c->self,
335 c->remote_name ? c->remote_name : "???", n);
337 s = channel_open_message();
338 debug3("channel %d: status: %s", c->self, s);
342 shutdown(c->sock, SHUT_RDWR);
344 shutdown(c->ctl_fd, SHUT_RDWR);
345 channel_close_fds(c);
346 buffer_free(&c->input);
347 buffer_free(&c->output);
348 buffer_free(&c->extended);
349 if (c->remote_name) {
350 xfree(c->remote_name);
351 c->remote_name = NULL;
353 channels[c->self] = NULL;
358 channel_free_all(void)
362 for (i = 0; i < channels_alloc; i++)
363 if (channels[i] != NULL)
364 channel_free(channels[i]);
368 * Closes the sockets/fds of all channels. This is used to close extra file
369 * descriptors after a fork.
373 channel_close_all(void)
377 for (i = 0; i < channels_alloc; i++)
378 if (channels[i] != NULL)
379 channel_close_fds(channels[i]);
383 * Stop listening to channels.
387 channel_stop_listening(void)
392 for (i = 0; i < channels_alloc; i++) {
396 case SSH_CHANNEL_AUTH_SOCKET:
397 case SSH_CHANNEL_PORT_LISTENER:
398 case SSH_CHANNEL_RPORT_LISTENER:
399 case SSH_CHANNEL_X11_LISTENER:
400 channel_close_fd(&c->sock);
409 * Returns true if no channel has too much buffered data, and false if one or
410 * more channel is overfull.
414 channel_not_very_much_buffered_data(void)
419 for (i = 0; i < channels_alloc; i++) {
421 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
424 buffer_len(&c->input) > packet_get_maxsize()) {
425 debug2("channel %d: big input buffer %d",
426 c->self, buffer_len(&c->input));
430 if (buffer_len(&c->output) > packet_get_maxsize()) {
431 debug2("channel %d: big output buffer %u > %u",
432 c->self, buffer_len(&c->output),
433 packet_get_maxsize());
441 /* Returns true if any channel is still open. */
444 channel_still_open(void)
449 for (i = 0; i < channels_alloc; i++) {
454 case SSH_CHANNEL_X11_LISTENER:
455 case SSH_CHANNEL_PORT_LISTENER:
456 case SSH_CHANNEL_RPORT_LISTENER:
457 case SSH_CHANNEL_CLOSED:
458 case SSH_CHANNEL_AUTH_SOCKET:
459 case SSH_CHANNEL_DYNAMIC:
460 case SSH_CHANNEL_CONNECTING:
461 case SSH_CHANNEL_ZOMBIE:
463 case SSH_CHANNEL_LARVAL:
465 fatal("cannot happen: SSH_CHANNEL_LARVAL");
467 case SSH_CHANNEL_OPENING:
468 case SSH_CHANNEL_OPEN:
469 case SSH_CHANNEL_X11_OPEN:
471 case SSH_CHANNEL_INPUT_DRAINING:
472 case SSH_CHANNEL_OUTPUT_DRAINING:
474 fatal("cannot happen: OUT_DRAIN");
477 fatal("channel_still_open: bad channel type %d", c->type);
484 /* Returns the id of an open channel suitable for keepaliving */
487 channel_find_open(void)
492 for (i = 0; i < channels_alloc; i++) {
494 if (c == NULL || c->remote_id < 0)
497 case SSH_CHANNEL_CLOSED:
498 case SSH_CHANNEL_DYNAMIC:
499 case SSH_CHANNEL_X11_LISTENER:
500 case SSH_CHANNEL_PORT_LISTENER:
501 case SSH_CHANNEL_RPORT_LISTENER:
502 case SSH_CHANNEL_OPENING:
503 case SSH_CHANNEL_CONNECTING:
504 case SSH_CHANNEL_ZOMBIE:
506 case SSH_CHANNEL_LARVAL:
507 case SSH_CHANNEL_AUTH_SOCKET:
508 case SSH_CHANNEL_OPEN:
509 case SSH_CHANNEL_X11_OPEN:
511 case SSH_CHANNEL_INPUT_DRAINING:
512 case SSH_CHANNEL_OUTPUT_DRAINING:
514 fatal("cannot happen: OUT_DRAIN");
517 fatal("channel_find_open: bad channel type %d", c->type);
526 * Returns a message describing the currently open forwarded connections,
527 * suitable for sending to the client. The message contains crlf pairs for
532 channel_open_message(void)
539 buffer_init(&buffer);
540 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
541 buffer_append(&buffer, buf, strlen(buf));
542 for (i = 0; i < channels_alloc; i++) {
547 case SSH_CHANNEL_X11_LISTENER:
548 case SSH_CHANNEL_PORT_LISTENER:
549 case SSH_CHANNEL_RPORT_LISTENER:
550 case SSH_CHANNEL_CLOSED:
551 case SSH_CHANNEL_AUTH_SOCKET:
552 case SSH_CHANNEL_ZOMBIE:
554 case SSH_CHANNEL_LARVAL:
555 case SSH_CHANNEL_OPENING:
556 case SSH_CHANNEL_CONNECTING:
557 case SSH_CHANNEL_DYNAMIC:
558 case SSH_CHANNEL_OPEN:
559 case SSH_CHANNEL_X11_OPEN:
560 case SSH_CHANNEL_INPUT_DRAINING:
561 case SSH_CHANNEL_OUTPUT_DRAINING:
562 snprintf(buf, sizeof buf,
563 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
564 c->self, c->remote_name,
565 c->type, c->remote_id,
566 c->istate, buffer_len(&c->input),
567 c->ostate, buffer_len(&c->output),
568 c->rfd, c->wfd, c->ctl_fd);
569 buffer_append(&buffer, buf, strlen(buf));
572 fatal("channel_open_message: bad channel type %d", c->type);
576 buffer_append(&buffer, "\0", 1);
577 cp = xstrdup(buffer_ptr(&buffer));
578 buffer_free(&buffer);
583 channel_send_open(int id)
585 Channel *c = channel_lookup(id);
588 logit("channel_send_open: %d: bad id", id);
591 debug2("channel %d: send open", id);
592 packet_start(SSH2_MSG_CHANNEL_OPEN);
593 packet_put_cstring(c->ctype);
594 packet_put_int(c->self);
595 packet_put_int(c->local_window);
596 packet_put_int(c->local_maxpacket);
601 channel_request_start(int id, char *service, int wantconfirm)
603 Channel *c = channel_lookup(id);
606 logit("channel_request_start: %d: unknown channel id", id);
609 debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
610 packet_start(SSH2_MSG_CHANNEL_REQUEST);
611 packet_put_int(c->remote_id);
612 packet_put_cstring(service);
613 packet_put_char(wantconfirm);
616 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx)
618 Channel *c = channel_lookup(id);
621 logit("channel_register_comfirm: %d: bad id", id);
625 c->confirm_ctx = ctx;
628 channel_register_cleanup(int id, channel_callback_fn *fn)
630 Channel *c = channel_lookup(id);
633 logit("channel_register_cleanup: %d: bad id", id);
639 channel_cancel_cleanup(int id)
641 Channel *c = channel_lookup(id);
644 logit("channel_cancel_cleanup: %d: bad id", id);
647 c->detach_user = NULL;
650 channel_register_filter(int id, channel_filter_fn *fn)
652 Channel *c = channel_lookup(id);
655 logit("channel_register_filter: %d: bad id", id);
658 c->input_filter = fn;
662 channel_set_fds(int id, int rfd, int wfd, int efd,
663 int extusage, int nonblock, u_int window_max)
665 Channel *c = channel_lookup(id);
667 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
668 fatal("channel_activate for non-larval channel %d.", id);
669 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
670 c->type = SSH_CHANNEL_OPEN;
671 c->local_window = c->local_window_max = window_max;
672 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
673 packet_put_int(c->remote_id);
674 packet_put_int(c->local_window);
679 * 'channel_pre*' are called just before select() to add any bits relevant to
680 * channels in the select bitmasks.
683 * 'channel_post*': perform any appropriate operations for channels which
684 * have events pending.
686 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
687 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
688 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
691 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
693 FD_SET(c->sock, readset);
697 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
699 debug3("channel %d: waiting for connection", c->self);
700 FD_SET(c->sock, writeset);
704 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
706 if (buffer_len(&c->input) < packet_get_maxsize())
707 FD_SET(c->sock, readset);
708 if (buffer_len(&c->output) > 0)
709 FD_SET(c->sock, writeset);
713 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
715 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
717 /* check buffer limits */
718 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF));
720 if (c->istate == CHAN_INPUT_OPEN &&
722 buffer_len(&c->input) < limit)
723 FD_SET(c->rfd, readset);
724 if (c->ostate == CHAN_OUTPUT_OPEN ||
725 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
726 if (buffer_len(&c->output) > 0) {
727 FD_SET(c->wfd, writeset);
728 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
729 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
730 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
731 c->self, c->efd, buffer_len(&c->extended));
736 /** XXX check close conditions, too */
737 if (compat20 && c->efd != -1) {
738 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
739 buffer_len(&c->extended) > 0)
740 FD_SET(c->efd, writeset);
741 else if (!(c->flags & CHAN_EOF_SENT) &&
742 c->extended_usage == CHAN_EXTENDED_READ &&
743 buffer_len(&c->extended) < c->remote_window)
744 FD_SET(c->efd, readset);
746 /* XXX: What about efd? races? */
747 if (compat20 && c->ctl_fd != -1 &&
748 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
749 FD_SET(c->ctl_fd, readset);
753 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
755 if (buffer_len(&c->input) == 0) {
756 packet_start(SSH_MSG_CHANNEL_CLOSE);
757 packet_put_int(c->remote_id);
759 c->type = SSH_CHANNEL_CLOSED;
760 debug2("channel %d: closing after input drain.", c->self);
765 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
767 if (buffer_len(&c->output) == 0)
770 FD_SET(c->sock, writeset);
774 * This is a special state for X11 authentication spoofing. An opened X11
775 * connection (when authentication spoofing is being done) remains in this
776 * state until the first packet has been completely read. The authentication
777 * data in that packet is then substituted by the real data if it matches the
778 * fake data, and the channel is put into normal mode.
779 * XXX All this happens at the client side.
780 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
783 x11_open_helper(Buffer *b)
786 u_int proto_len, data_len;
788 /* Check if the fixed size part of the packet is in buffer. */
789 if (buffer_len(b) < 12)
792 /* Parse the lengths of variable-length fields. */
794 if (ucp[0] == 0x42) { /* Byte order MSB first. */
795 proto_len = 256 * ucp[6] + ucp[7];
796 data_len = 256 * ucp[8] + ucp[9];
797 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
798 proto_len = ucp[6] + 256 * ucp[7];
799 data_len = ucp[8] + 256 * ucp[9];
801 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
806 /* Check if the whole packet is in buffer. */
808 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
811 /* Check if authentication protocol matches. */
812 if (proto_len != strlen(x11_saved_proto) ||
813 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
814 debug2("X11 connection uses different authentication protocol.");
817 /* Check if authentication data matches our fake data. */
818 if (data_len != x11_fake_data_len ||
819 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
820 x11_fake_data, x11_fake_data_len) != 0) {
821 debug2("X11 auth data does not match fake data.");
824 /* Check fake data length */
825 if (x11_fake_data_len != x11_saved_data_len) {
826 error("X11 fake_data_len %d != saved_data_len %d",
827 x11_fake_data_len, x11_saved_data_len);
831 * Received authentication protocol and data match
832 * our fake data. Substitute the fake data with real
835 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
836 x11_saved_data, x11_saved_data_len);
841 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
843 int ret = x11_open_helper(&c->output);
846 /* Start normal processing for the channel. */
847 c->type = SSH_CHANNEL_OPEN;
848 channel_pre_open_13(c, readset, writeset);
849 } else if (ret == -1) {
851 * We have received an X11 connection that has bad
852 * authentication information.
854 logit("X11 connection rejected because of wrong authentication.");
855 buffer_clear(&c->input);
856 buffer_clear(&c->output);
857 channel_close_fd(&c->sock);
859 c->type = SSH_CHANNEL_CLOSED;
860 packet_start(SSH_MSG_CHANNEL_CLOSE);
861 packet_put_int(c->remote_id);
867 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
869 int ret = x11_open_helper(&c->output);
871 /* c->force_drain = 1; */
874 c->type = SSH_CHANNEL_OPEN;
875 channel_pre_open(c, readset, writeset);
876 } else if (ret == -1) {
877 logit("X11 connection rejected because of wrong authentication.");
878 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
880 buffer_clear(&c->input);
882 buffer_clear(&c->output);
883 /* for proto v1, the peer will send an IEOF */
885 chan_write_failed(c);
887 c->type = SSH_CHANNEL_OPEN;
888 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
892 /* try to decode a socks4 header */
894 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
897 u_int len, have, i, found;
903 struct in_addr dest_addr;
906 debug2("channel %d: decode socks4", c->self);
908 have = buffer_len(&c->input);
909 len = sizeof(s4_req);
912 p = buffer_ptr(&c->input);
913 for (found = 0, i = len; i < have; i++) {
919 /* the peer is probably sending garbage */
920 debug("channel %d: decode socks4: too long",
927 buffer_get(&c->input, (char *)&s4_req.version, 1);
928 buffer_get(&c->input, (char *)&s4_req.command, 1);
929 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
930 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
931 have = buffer_len(&c->input);
932 p = buffer_ptr(&c->input);
934 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
936 fatal("channel %d: decode socks4: len %d > have %d",
938 strlcpy(username, p, sizeof(username));
939 buffer_consume(&c->input, len);
940 buffer_consume(&c->input, 1); /* trailing '\0' */
942 host = inet_ntoa(s4_req.dest_addr);
943 strlcpy(c->path, host, sizeof(c->path));
944 c->host_port = ntohs(s4_req.dest_port);
946 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
947 c->self, host, c->host_port, s4_req.command);
949 if (s4_req.command != 1) {
950 debug("channel %d: cannot handle: socks4 cn %d",
951 c->self, s4_req.command);
954 s4_rsp.version = 0; /* vn: 0 for reply */
955 s4_rsp.command = 90; /* cd: req granted */
956 s4_rsp.dest_port = 0; /* ignored */
957 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
958 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
962 /* try to decode a socks5 header */
963 #define SSH_SOCKS5_AUTHDONE 0x1000
964 #define SSH_SOCKS5_NOAUTH 0x00
965 #define SSH_SOCKS5_IPV4 0x01
966 #define SSH_SOCKS5_DOMAIN 0x03
967 #define SSH_SOCKS5_IPV6 0x04
968 #define SSH_SOCKS5_CONNECT 0x01
969 #define SSH_SOCKS5_SUCCESS 0x00
972 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
981 u_char *p, dest_addr[255+1];
982 u_int have, i, found, nmethods, addrlen, af;
984 debug2("channel %d: decode socks5", c->self);
985 p = buffer_ptr(&c->input);
988 have = buffer_len(&c->input);
989 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
990 /* format: ver | nmethods | methods */
994 if (have < nmethods + 2)
996 /* look for method: "NO AUTHENTICATION REQUIRED" */
997 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
998 if (p[i] == SSH_SOCKS5_NOAUTH ) {
1004 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1008 buffer_consume(&c->input, nmethods + 2);
1009 buffer_put_char(&c->output, 0x05); /* version */
1010 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1011 FD_SET(c->sock, writeset);
1012 c->flags |= SSH_SOCKS5_AUTHDONE;
1013 debug2("channel %d: socks5 auth done", c->self);
1014 return 0; /* need more */
1016 debug2("channel %d: socks5 post auth", c->self);
1017 if (have < sizeof(s5_req)+1)
1018 return 0; /* need more */
1019 memcpy((char *)&s5_req, p, sizeof(s5_req));
1020 if (s5_req.version != 0x05 ||
1021 s5_req.command != SSH_SOCKS5_CONNECT ||
1022 s5_req.reserved != 0x00) {
1023 debug2("channel %d: only socks5 connect supported", c->self);
1026 switch (s5_req.atyp){
1027 case SSH_SOCKS5_IPV4:
1031 case SSH_SOCKS5_DOMAIN:
1032 addrlen = p[sizeof(s5_req)];
1035 case SSH_SOCKS5_IPV6:
1040 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1043 if (have < 4 + addrlen + 2)
1045 buffer_consume(&c->input, sizeof(s5_req));
1046 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1047 buffer_consume(&c->input, 1); /* host string length */
1048 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1049 buffer_get(&c->input, (char *)&dest_port, 2);
1050 dest_addr[addrlen] = '\0';
1051 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1052 strlcpy(c->path, (char *)dest_addr, sizeof(c->path));
1053 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1055 c->host_port = ntohs(dest_port);
1057 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1058 c->self, c->path, c->host_port, s5_req.command);
1060 s5_rsp.version = 0x05;
1061 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1062 s5_rsp.reserved = 0; /* ignored */
1063 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1064 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1065 dest_port = 0; /* ignored */
1067 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1068 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1069 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1073 /* dynamic port forwarding */
1075 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1081 have = buffer_len(&c->input);
1083 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1084 /* buffer_dump(&c->input); */
1085 /* check if the fixed size part of the packet is in buffer. */
1088 FD_SET(c->sock, readset);
1091 /* try to guess the protocol */
1092 p = buffer_ptr(&c->input);
1095 ret = channel_decode_socks4(c, readset, writeset);
1098 ret = channel_decode_socks5(c, readset, writeset);
1106 } else if (ret == 0) {
1107 debug2("channel %d: pre_dynamic: need more", c->self);
1109 FD_SET(c->sock, readset);
1111 /* switch to the next state */
1112 c->type = SSH_CHANNEL_OPENING;
1113 port_open_helper(c, "direct-tcpip");
1117 /* This is our fake X11 server socket. */
1119 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1122 struct sockaddr addr;
1125 char buf[16384], *remote_ipaddr;
1128 if (FD_ISSET(c->sock, readset)) {
1129 debug("X11 connection requested.");
1130 addrlen = sizeof(addr);
1131 newsock = accept(c->sock, &addr, &addrlen);
1132 if (c->single_connection) {
1133 debug2("single_connection: closing X11 listener.");
1134 channel_close_fd(&c->sock);
1138 error("accept: %.100s", strerror(errno));
1141 set_nodelay(newsock);
1142 remote_ipaddr = get_peer_ipaddr(newsock);
1143 remote_port = get_peer_port(newsock);
1144 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1145 remote_ipaddr, remote_port);
1147 nc = channel_new("accepted x11 socket",
1148 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1149 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1151 packet_start(SSH2_MSG_CHANNEL_OPEN);
1152 packet_put_cstring("x11");
1153 packet_put_int(nc->self);
1154 packet_put_int(nc->local_window_max);
1155 packet_put_int(nc->local_maxpacket);
1156 /* originator ipaddr and port */
1157 packet_put_cstring(remote_ipaddr);
1158 if (datafellows & SSH_BUG_X11FWD) {
1159 debug2("ssh2 x11 bug compat mode");
1161 packet_put_int(remote_port);
1165 packet_start(SSH_SMSG_X11_OPEN);
1166 packet_put_int(nc->self);
1167 if (packet_get_protocol_flags() &
1168 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1169 packet_put_cstring(buf);
1172 xfree(remote_ipaddr);
1177 port_open_helper(Channel *c, char *rtype)
1181 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1182 int remote_port = get_peer_port(c->sock);
1184 direct = (strcmp(rtype, "direct-tcpip") == 0);
1186 snprintf(buf, sizeof buf,
1187 "%s: listening port %d for %.100s port %d, "
1188 "connect from %.200s port %d",
1189 rtype, c->listening_port, c->path, c->host_port,
1190 remote_ipaddr, remote_port);
1192 xfree(c->remote_name);
1193 c->remote_name = xstrdup(buf);
1196 packet_start(SSH2_MSG_CHANNEL_OPEN);
1197 packet_put_cstring(rtype);
1198 packet_put_int(c->self);
1199 packet_put_int(c->local_window_max);
1200 packet_put_int(c->local_maxpacket);
1202 /* target host, port */
1203 packet_put_cstring(c->path);
1204 packet_put_int(c->host_port);
1206 /* listen address, port */
1207 packet_put_cstring(c->path);
1208 packet_put_int(c->listening_port);
1210 /* originator host and port */
1211 packet_put_cstring(remote_ipaddr);
1212 packet_put_int((u_int)remote_port);
1215 packet_start(SSH_MSG_PORT_OPEN);
1216 packet_put_int(c->self);
1217 packet_put_cstring(c->path);
1218 packet_put_int(c->host_port);
1219 if (packet_get_protocol_flags() &
1220 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1221 packet_put_cstring(c->remote_name);
1224 xfree(remote_ipaddr);
1228 * This socket is listening for connections to a forwarded TCP/IP port.
1231 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1234 struct sockaddr addr;
1235 int newsock, nextstate;
1239 if (FD_ISSET(c->sock, readset)) {
1240 debug("Connection to port %d forwarding "
1241 "to %.100s port %d requested.",
1242 c->listening_port, c->path, c->host_port);
1244 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1245 nextstate = SSH_CHANNEL_OPENING;
1246 rtype = "forwarded-tcpip";
1248 if (c->host_port == 0) {
1249 nextstate = SSH_CHANNEL_DYNAMIC;
1250 rtype = "dynamic-tcpip";
1252 nextstate = SSH_CHANNEL_OPENING;
1253 rtype = "direct-tcpip";
1257 addrlen = sizeof(addr);
1258 newsock = accept(c->sock, &addr, &addrlen);
1260 error("accept: %.100s", strerror(errno));
1263 set_nodelay(newsock);
1264 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1265 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1266 nc->listening_port = c->listening_port;
1267 nc->host_port = c->host_port;
1268 strlcpy(nc->path, c->path, sizeof(nc->path));
1270 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1272 * do not call the channel_post handler until
1273 * this flag has been reset by a pre-handler.
1274 * otherwise the FD_ISSET calls might overflow
1278 port_open_helper(nc, rtype);
1284 * This is the authentication agent socket listening for connections from
1288 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1292 struct sockaddr addr;
1295 if (FD_ISSET(c->sock, readset)) {
1296 addrlen = sizeof(addr);
1297 newsock = accept(c->sock, &addr, &addrlen);
1299 error("accept from auth socket: %.100s", strerror(errno));
1302 nc = channel_new("accepted auth socket",
1303 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1304 c->local_window_max, c->local_maxpacket,
1305 0, "accepted auth socket", 1);
1307 packet_start(SSH2_MSG_CHANNEL_OPEN);
1308 packet_put_cstring("auth-agent@openssh.com");
1309 packet_put_int(nc->self);
1310 packet_put_int(c->local_window_max);
1311 packet_put_int(c->local_maxpacket);
1313 packet_start(SSH_SMSG_AGENT_OPEN);
1314 packet_put_int(nc->self);
1321 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1324 socklen_t sz = sizeof(err);
1326 if (FD_ISSET(c->sock, writeset)) {
1327 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1329 error("getsockopt SO_ERROR failed");
1332 debug("channel %d: connected", c->self);
1333 c->type = SSH_CHANNEL_OPEN;
1335 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1336 packet_put_int(c->remote_id);
1337 packet_put_int(c->self);
1338 packet_put_int(c->local_window);
1339 packet_put_int(c->local_maxpacket);
1341 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1342 packet_put_int(c->remote_id);
1343 packet_put_int(c->self);
1346 debug("channel %d: not connected: %s",
1347 c->self, strerror(err));
1349 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1350 packet_put_int(c->remote_id);
1351 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1352 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1353 packet_put_cstring(strerror(err));
1354 packet_put_cstring("");
1357 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1358 packet_put_int(c->remote_id);
1367 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1369 char buf[CHAN_RBUF];
1373 FD_ISSET(c->rfd, readset)) {
1374 len = read(c->rfd, buf, sizeof(buf));
1375 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1378 debug2("channel %d: read<=0 rfd %d len %d",
1379 c->self, c->rfd, len);
1380 if (c->type != SSH_CHANNEL_OPEN) {
1381 debug2("channel %d: not open", c->self);
1384 } else if (compat13) {
1385 buffer_clear(&c->output);
1386 c->type = SSH_CHANNEL_INPUT_DRAINING;
1387 debug2("channel %d: input draining.", c->self);
1389 chan_read_failed(c);
1393 if (c->input_filter != NULL) {
1394 if (c->input_filter(c, buf, len) == -1) {
1395 debug2("channel %d: filter stops", c->self);
1396 chan_read_failed(c);
1399 buffer_append(&c->input, buf, len);
1405 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1412 /* Send buffered output data to the socket. */
1414 FD_ISSET(c->wfd, writeset) &&
1415 buffer_len(&c->output) > 0) {
1416 data = buffer_ptr(&c->output);
1417 dlen = buffer_len(&c->output);
1419 /* XXX: Later AIX versions can't push as much data to tty */
1420 if (compat20 && c->wfd_isatty)
1421 dlen = MIN(dlen, 8*1024);
1423 len = write(c->wfd, data, dlen);
1424 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1427 if (c->type != SSH_CHANNEL_OPEN) {
1428 debug2("channel %d: not open", c->self);
1431 } else if (compat13) {
1432 buffer_clear(&c->output);
1433 debug2("channel %d: input draining.", c->self);
1434 c->type = SSH_CHANNEL_INPUT_DRAINING;
1436 chan_write_failed(c);
1440 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1441 if (tcgetattr(c->wfd, &tio) == 0 &&
1442 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1444 * Simulate echo to reduce the impact of
1445 * traffic analysis. We need to match the
1446 * size of a SSH2_MSG_CHANNEL_DATA message
1447 * (4 byte channel id + data)
1449 packet_send_ignore(4 + len);
1453 buffer_consume(&c->output, len);
1454 if (compat20 && len > 0) {
1455 c->local_consumed += len;
1461 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1463 char buf[CHAN_RBUF];
1466 /** XXX handle drain efd, too */
1468 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1469 FD_ISSET(c->efd, writeset) &&
1470 buffer_len(&c->extended) > 0) {
1471 len = write(c->efd, buffer_ptr(&c->extended),
1472 buffer_len(&c->extended));
1473 debug2("channel %d: written %d to efd %d",
1474 c->self, len, c->efd);
1475 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1478 debug2("channel %d: closing write-efd %d",
1480 channel_close_fd(&c->efd);
1482 buffer_consume(&c->extended, len);
1483 c->local_consumed += len;
1485 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1486 FD_ISSET(c->efd, readset)) {
1487 len = read(c->efd, buf, sizeof(buf));
1488 debug2("channel %d: read %d from efd %d",
1489 c->self, len, c->efd);
1490 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1493 debug2("channel %d: closing read-efd %d",
1495 channel_close_fd(&c->efd);
1497 buffer_append(&c->extended, buf, len);
1504 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset)
1509 /* Monitor control fd to detect if the slave client exits */
1510 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1511 len = read(c->ctl_fd, buf, sizeof(buf));
1512 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1515 debug2("channel %d: ctl read<=0", c->self);
1516 if (c->type != SSH_CHANNEL_OPEN) {
1517 debug2("channel %d: not open", c->self);
1521 chan_read_failed(c);
1522 chan_write_failed(c);
1526 fatal("%s: unexpected data on ctl fd", __func__);
1531 channel_check_window(Channel *c)
1533 if (c->type == SSH_CHANNEL_OPEN &&
1534 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1535 c->local_window < c->local_window_max/2 &&
1536 c->local_consumed > 0) {
1537 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1538 packet_put_int(c->remote_id);
1539 packet_put_int(c->local_consumed);
1541 debug2("channel %d: window %d sent adjust %d",
1542 c->self, c->local_window,
1544 c->local_window += c->local_consumed;
1545 c->local_consumed = 0;
1551 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1555 channel_handle_rfd(c, readset, writeset);
1556 channel_handle_wfd(c, readset, writeset);
1559 channel_handle_efd(c, readset, writeset);
1560 channel_handle_ctl(c, readset, writeset);
1561 channel_check_window(c);
1565 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1569 /* Send buffered output data to the socket. */
1570 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1571 len = write(c->sock, buffer_ptr(&c->output),
1572 buffer_len(&c->output));
1574 buffer_clear(&c->output);
1576 buffer_consume(&c->output, len);
1581 channel_handler_init_20(void)
1583 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1584 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1585 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1586 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1587 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1588 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1589 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1590 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1592 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1593 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1594 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1595 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1596 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1597 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1598 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1602 channel_handler_init_13(void)
1604 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1605 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1606 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1607 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1608 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1609 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1610 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1611 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1612 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1614 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1615 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1616 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1617 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1618 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1619 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1620 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1624 channel_handler_init_15(void)
1626 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1627 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1628 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1629 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1630 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1631 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1632 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1634 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1635 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1636 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1637 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1638 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1639 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1643 channel_handler_init(void)
1647 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1648 channel_pre[i] = NULL;
1649 channel_post[i] = NULL;
1652 channel_handler_init_20();
1654 channel_handler_init_13();
1656 channel_handler_init_15();
1659 /* gc dead channels */
1661 channel_garbage_collect(Channel *c)
1665 if (c->detach_user != NULL) {
1666 if (!chan_is_dead(c, 0))
1668 debug2("channel %d: gc: notify user", c->self);
1669 c->detach_user(c->self, NULL);
1670 /* if we still have a callback */
1671 if (c->detach_user != NULL)
1673 debug2("channel %d: gc: user detached", c->self);
1675 if (!chan_is_dead(c, 1))
1677 debug2("channel %d: garbage collecting", c->self);
1682 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1684 static int did_init = 0;
1689 channel_handler_init();
1692 for (i = 0; i < channels_alloc; i++) {
1696 if (ftab[c->type] != NULL)
1697 (*ftab[c->type])(c, readset, writeset);
1698 channel_garbage_collect(c);
1703 * Allocate/update select bitmasks and add any bits relevant to channels in
1707 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1708 u_int *nallocp, int rekeying)
1712 n = MAX(*maxfdp, channel_max_fd);
1714 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1715 /* perhaps check sz < nalloc/2 and shrink? */
1716 if (*readsetp == NULL || sz > *nallocp) {
1717 *readsetp = xrealloc(*readsetp, sz);
1718 *writesetp = xrealloc(*writesetp, sz);
1722 memset(*readsetp, 0, sz);
1723 memset(*writesetp, 0, sz);
1726 channel_handler(channel_pre, *readsetp, *writesetp);
1730 * After select, perform any appropriate operations for channels which have
1734 channel_after_select(fd_set * readset, fd_set * writeset)
1736 channel_handler(channel_post, readset, writeset);
1740 /* If there is data to send to the connection, enqueue some of it now. */
1743 channel_output_poll(void)
1748 for (i = 0; i < channels_alloc; i++) {
1754 * We are only interested in channels that can have buffered
1758 if (c->type != SSH_CHANNEL_OPEN &&
1759 c->type != SSH_CHANNEL_INPUT_DRAINING)
1762 if (c->type != SSH_CHANNEL_OPEN)
1766 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1767 /* XXX is this true? */
1768 debug3("channel %d: will not send data after close", c->self);
1772 /* Get the amount of buffered data for this channel. */
1773 if ((c->istate == CHAN_INPUT_OPEN ||
1774 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1775 (len = buffer_len(&c->input)) > 0) {
1777 * Send some data for the other side over the secure
1781 if (len > c->remote_window)
1782 len = c->remote_window;
1783 if (len > c->remote_maxpacket)
1784 len = c->remote_maxpacket;
1786 if (packet_is_interactive()) {
1790 /* Keep the packets at reasonable size. */
1791 if (len > packet_get_maxsize()/2)
1792 len = packet_get_maxsize()/2;
1796 packet_start(compat20 ?
1797 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1798 packet_put_int(c->remote_id);
1799 packet_put_string(buffer_ptr(&c->input), len);
1801 buffer_consume(&c->input, len);
1802 c->remote_window -= len;
1804 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1806 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1808 * input-buffer is empty and read-socket shutdown:
1809 * tell peer, that we will not send more data: send IEOF.
1810 * hack for extended data: delay EOF if EFD still in use.
1812 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1813 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1814 c->self, c->efd, buffer_len(&c->extended));
1818 /* Send extended data, i.e. stderr */
1820 !(c->flags & CHAN_EOF_SENT) &&
1821 c->remote_window > 0 &&
1822 (len = buffer_len(&c->extended)) > 0 &&
1823 c->extended_usage == CHAN_EXTENDED_READ) {
1824 debug2("channel %d: rwin %u elen %u euse %d",
1825 c->self, c->remote_window, buffer_len(&c->extended),
1827 if (len > c->remote_window)
1828 len = c->remote_window;
1829 if (len > c->remote_maxpacket)
1830 len = c->remote_maxpacket;
1831 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1832 packet_put_int(c->remote_id);
1833 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1834 packet_put_string(buffer_ptr(&c->extended), len);
1836 buffer_consume(&c->extended, len);
1837 c->remote_window -= len;
1838 debug2("channel %d: sent ext data %d", c->self, len);
1844 /* -- protocol input */
1847 channel_input_data(int type, u_int32_t seq, void *ctxt)
1854 /* Get the channel number and verify it. */
1855 id = packet_get_int();
1856 c = channel_lookup(id);
1858 packet_disconnect("Received data for nonexistent channel %d.", id);
1860 /* Ignore any data for non-open channels (might happen on close) */
1861 if (c->type != SSH_CHANNEL_OPEN &&
1862 c->type != SSH_CHANNEL_X11_OPEN)
1866 data = packet_get_string(&data_len);
1869 * Ignore data for protocol > 1.3 if output end is no longer open.
1870 * For protocol 2 the sending side is reducing its window as it sends
1871 * data, so we must 'fake' consumption of the data in order to ensure
1872 * that window updates are sent back. Otherwise the connection might
1875 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1877 c->local_window -= data_len;
1878 c->local_consumed += data_len;
1885 if (data_len > c->local_maxpacket) {
1886 logit("channel %d: rcvd big packet %d, maxpack %d",
1887 c->self, data_len, c->local_maxpacket);
1889 if (data_len > c->local_window) {
1890 logit("channel %d: rcvd too much data %d, win %d",
1891 c->self, data_len, c->local_window);
1895 c->local_window -= data_len;
1898 buffer_append(&c->output, data, data_len);
1903 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1907 u_int data_len, tcode;
1910 /* Get the channel number and verify it. */
1911 id = packet_get_int();
1912 c = channel_lookup(id);
1915 packet_disconnect("Received extended_data for bad channel %d.", id);
1916 if (c->type != SSH_CHANNEL_OPEN) {
1917 logit("channel %d: ext data for non open", id);
1920 if (c->flags & CHAN_EOF_RCVD) {
1921 if (datafellows & SSH_BUG_EXTEOF)
1922 debug("channel %d: accepting ext data after eof", id);
1924 packet_disconnect("Received extended_data after EOF "
1925 "on channel %d.", id);
1927 tcode = packet_get_int();
1929 c->extended_usage != CHAN_EXTENDED_WRITE ||
1930 tcode != SSH2_EXTENDED_DATA_STDERR) {
1931 logit("channel %d: bad ext data", c->self);
1934 data = packet_get_string(&data_len);
1936 if (data_len > c->local_window) {
1937 logit("channel %d: rcvd too much extended_data %d, win %d",
1938 c->self, data_len, c->local_window);
1942 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1943 c->local_window -= data_len;
1944 buffer_append(&c->extended, data, data_len);
1949 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1954 id = packet_get_int();
1956 c = channel_lookup(id);
1958 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1961 /* XXX force input close */
1962 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1963 debug("channel %d: FORCE input drain", c->self);
1964 c->istate = CHAN_INPUT_WAIT_DRAIN;
1965 if (buffer_len(&c->input) == 0)
1972 channel_input_close(int type, u_int32_t seq, void *ctxt)
1977 id = packet_get_int();
1979 c = channel_lookup(id);
1981 packet_disconnect("Received close for nonexistent channel %d.", id);
1984 * Send a confirmation that we have closed the channel and no more
1985 * data is coming for it.
1987 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1988 packet_put_int(c->remote_id);
1992 * If the channel is in closed state, we have sent a close request,
1993 * and the other side will eventually respond with a confirmation.
1994 * Thus, we cannot free the channel here, because then there would be
1995 * no-one to receive the confirmation. The channel gets freed when
1996 * the confirmation arrives.
1998 if (c->type != SSH_CHANNEL_CLOSED) {
2000 * Not a closed channel - mark it as draining, which will
2001 * cause it to be freed later.
2003 buffer_clear(&c->input);
2004 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2008 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2010 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2012 int id = packet_get_int();
2013 Channel *c = channel_lookup(id);
2017 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2018 chan_rcvd_oclose(c);
2022 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2024 int id = packet_get_int();
2025 Channel *c = channel_lookup(id);
2029 packet_disconnect("Received close confirmation for "
2030 "out-of-range channel %d.", id);
2031 if (c->type != SSH_CHANNEL_CLOSED)
2032 packet_disconnect("Received close confirmation for "
2033 "non-closed channel %d (type %d).", id, c->type);
2038 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2043 id = packet_get_int();
2044 c = channel_lookup(id);
2046 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2047 packet_disconnect("Received open confirmation for "
2048 "non-opening channel %d.", id);
2049 remote_id = packet_get_int();
2050 /* Record the remote channel number and mark that the channel is now open. */
2051 c->remote_id = remote_id;
2052 c->type = SSH_CHANNEL_OPEN;
2055 c->remote_window = packet_get_int();
2056 c->remote_maxpacket = packet_get_int();
2058 debug2("callback start");
2059 c->confirm(c->self, c->confirm_ctx);
2060 debug2("callback done");
2062 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2063 c->remote_window, c->remote_maxpacket);
2069 reason2txt(int reason)
2072 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2073 return "administratively prohibited";
2074 case SSH2_OPEN_CONNECT_FAILED:
2075 return "connect failed";
2076 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2077 return "unknown channel type";
2078 case SSH2_OPEN_RESOURCE_SHORTAGE:
2079 return "resource shortage";
2081 return "unknown reason";
2085 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2088 char *msg = NULL, *lang = NULL;
2091 id = packet_get_int();
2092 c = channel_lookup(id);
2094 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2095 packet_disconnect("Received open failure for "
2096 "non-opening channel %d.", id);
2098 reason = packet_get_int();
2099 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2100 msg = packet_get_string(NULL);
2101 lang = packet_get_string(NULL);
2103 logit("channel %d: open failed: %s%s%s", id,
2104 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2111 /* Free the channel. This will also close the socket. */
2116 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2125 /* Get the channel number and verify it. */
2126 id = packet_get_int();
2127 c = channel_lookup(id);
2129 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2130 logit("Received window adjust for "
2131 "non-open channel %d.", id);
2134 adjust = packet_get_int();
2136 debug2("channel %d: rcvd adjust %u", id, adjust);
2137 c->remote_window += adjust;
2141 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2145 char *host, *originator_string;
2146 int remote_id, sock = -1;
2148 remote_id = packet_get_int();
2149 host = packet_get_string(NULL);
2150 host_port = packet_get_int();
2152 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2153 originator_string = packet_get_string(NULL);
2155 originator_string = xstrdup("unknown (remote did not supply name)");
2158 sock = channel_connect_to(host, host_port);
2160 c = channel_new("connected socket",
2161 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2162 originator_string, 1);
2163 c->remote_id = remote_id;
2165 xfree(originator_string);
2167 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2168 packet_put_int(remote_id);
2175 /* -- tcp forwarding */
2178 channel_set_af(int af)
2184 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2185 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2188 int sock, r, success = 0, on = 1, wildcard = 0, is_client;
2189 struct addrinfo hints, *ai, *aitop;
2190 const char *host, *addr;
2191 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2193 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2194 listen_addr : host_to_connect;
2195 is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2198 error("No forward host name.");
2201 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2202 error("Forward host name too long.");
2207 * Determine whether or not a port forward listens to loopback,
2208 * specified address or wildcard. On the client, a specified bind
2209 * address will always override gateway_ports. On the server, a
2210 * gateway_ports of 1 (``yes'') will override the client's
2211 * specification and force a wildcard bind, whereas a value of 2
2212 * (``clientspecified'') will bind to whatever address the client
2215 * Special-case listen_addrs are:
2217 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2218 * "" (empty string), "*" -> wildcard v4/v6
2219 * "localhost" -> loopback v4/v6
2222 if (listen_addr == NULL) {
2223 /* No address specified: default to gateway_ports setting */
2226 } else if (gateway_ports || is_client) {
2227 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2228 strcmp(listen_addr, "0.0.0.0") == 0) ||
2229 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2230 (!is_client && gateway_ports == 1))
2232 else if (strcmp(listen_addr, "localhost") != 0)
2236 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2237 type, wildcard, (addr == NULL) ? "NULL" : addr);
2240 * getaddrinfo returns a loopback address if the hostname is
2241 * set to NULL and hints.ai_flags is not AI_PASSIVE
2243 memset(&hints, 0, sizeof(hints));
2244 hints.ai_family = IPv4or6;
2245 hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2246 hints.ai_socktype = SOCK_STREAM;
2247 snprintf(strport, sizeof strport, "%d", listen_port);
2248 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2250 /* This really shouldn't happen */
2251 packet_disconnect("getaddrinfo: fatal error: %s",
2254 error("channel_setup_fwd_listener: "
2255 "getaddrinfo(%.64s): %s", addr, gai_strerror(r));
2260 for (ai = aitop; ai; ai = ai->ai_next) {
2261 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2263 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2264 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2265 error("channel_setup_fwd_listener: getnameinfo failed");
2268 /* Create a port to listen for the host. */
2269 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2271 /* this is no error since kernel may not support ipv6 */
2272 verbose("socket: %.100s", strerror(errno));
2276 * Set socket options.
2277 * Allow local port reuse in TIME_WAIT.
2279 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on,
2281 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
2283 debug("Local forwarding listening on %s port %s.", ntop, strport);
2285 /* Bind the socket to the address. */
2286 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2287 /* address can be in use ipv6 address is already bound */
2289 error("bind: %.100s", strerror(errno));
2291 verbose("bind: %.100s", strerror(errno));
2296 /* Start listening for connections on the socket. */
2297 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2298 error("listen: %.100s", strerror(errno));
2302 /* Allocate a channel number for the socket. */
2303 c = channel_new("port listener", type, sock, sock, -1,
2304 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2305 0, "port listener", 1);
2306 strlcpy(c->path, host, sizeof(c->path));
2307 c->host_port = port_to_connect;
2308 c->listening_port = listen_port;
2312 error("channel_setup_fwd_listener: cannot listen to port: %d",
2314 freeaddrinfo(aitop);
2319 channel_cancel_rport_listener(const char *host, u_short port)
2324 for (i = 0; i < channels_alloc; i++) {
2325 Channel *c = channels[i];
2327 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2328 strncmp(c->path, host, sizeof(c->path)) == 0 &&
2329 c->listening_port == port) {
2330 debug2("%s: close channel %d", __func__, i);
2339 /* protocol local port fwd, used by ssh (and sshd in v1) */
2341 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2342 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2344 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2345 listen_host, listen_port, host_to_connect, port_to_connect,
2349 /* protocol v2 remote port fwd, used by sshd */
2351 channel_setup_remote_fwd_listener(const char *listen_address,
2352 u_short listen_port, int gateway_ports)
2354 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2355 listen_address, listen_port, NULL, 0, gateway_ports);
2359 * Initiate forwarding of connections to port "port" on remote host through
2360 * the secure channel to host:port from local side.
2364 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2365 const char *host_to_connect, u_short port_to_connect)
2367 int type, success = 0;
2369 /* Record locally that connection to this host/port is permitted. */
2370 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2371 fatal("channel_request_remote_forwarding: too many forwards");
2373 /* Send the forward request to the remote side. */
2375 const char *address_to_bind;
2376 if (listen_host == NULL)
2377 address_to_bind = "localhost";
2378 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0)
2379 address_to_bind = "";
2381 address_to_bind = listen_host;
2383 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2384 packet_put_cstring("tcpip-forward");
2385 packet_put_char(1); /* boolean: want reply */
2386 packet_put_cstring(address_to_bind);
2387 packet_put_int(listen_port);
2389 packet_write_wait();
2390 /* Assume that server accepts the request */
2393 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2394 packet_put_int(listen_port);
2395 packet_put_cstring(host_to_connect);
2396 packet_put_int(port_to_connect);
2398 packet_write_wait();
2400 /* Wait for response from the remote side. */
2401 type = packet_read();
2403 case SSH_SMSG_SUCCESS:
2406 case SSH_SMSG_FAILURE:
2407 logit("Warning: Server denied remote port forwarding.");
2410 /* Unknown packet */
2411 packet_disconnect("Protocol error for port forward request:"
2412 "received packet type %d.", type);
2416 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2417 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2418 permitted_opens[num_permitted_opens].listen_port = listen_port;
2419 num_permitted_opens++;
2424 * Request cancellation of remote forwarding of connection host:port from
2428 channel_request_rforward_cancel(const char *host, u_short port)
2435 for (i = 0; i < num_permitted_opens; i++) {
2436 if (permitted_opens[i].host_to_connect != NULL &&
2437 permitted_opens[i].listen_port == port)
2440 if (i >= num_permitted_opens) {
2441 debug("%s: requested forward not found", __func__);
2444 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2445 packet_put_cstring("cancel-tcpip-forward");
2447 packet_put_cstring(host == NULL ? "" : host);
2448 packet_put_int(port);
2451 permitted_opens[i].listen_port = 0;
2452 permitted_opens[i].port_to_connect = 0;
2453 free(permitted_opens[i].host_to_connect);
2454 permitted_opens[i].host_to_connect = NULL;
2458 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2459 * listening for the port, and sends back a success reply (or disconnect
2460 * message if there was an error). This never returns if there was an error.
2464 channel_input_port_forward_request(int is_root, int gateway_ports)
2466 u_short port, host_port;
2469 /* Get arguments from the packet. */
2470 port = packet_get_int();
2471 hostname = packet_get_string(NULL);
2472 host_port = packet_get_int();
2476 * Check that an unprivileged user is not trying to forward a
2479 if (port < IPPORT_RESERVED && !is_root)
2481 "Requested forwarding of port %d but user is not root.",
2484 packet_disconnect("Dynamic forwarding denied.");
2487 /* Initiate forwarding */
2488 channel_setup_local_fwd_listener(NULL, port, hostname,
2489 host_port, gateway_ports);
2491 /* Free the argument string. */
2496 * Permits opening to any host/port if permitted_opens[] is empty. This is
2497 * usually called by the server, because the user could connect to any port
2498 * anyway, and the server has no way to know but to trust the client anyway.
2501 channel_permit_all_opens(void)
2503 if (num_permitted_opens == 0)
2504 all_opens_permitted = 1;
2508 channel_add_permitted_opens(char *host, int port)
2510 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2511 fatal("channel_request_remote_forwarding: too many forwards");
2512 debug("allow port forwarding to host %s port %d", host, port);
2514 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2515 permitted_opens[num_permitted_opens].port_to_connect = port;
2516 num_permitted_opens++;
2518 all_opens_permitted = 0;
2522 channel_clear_permitted_opens(void)
2526 for (i = 0; i < num_permitted_opens; i++)
2527 if (permitted_opens[i].host_to_connect != NULL)
2528 xfree(permitted_opens[i].host_to_connect);
2529 num_permitted_opens = 0;
2534 /* return socket to remote host, port */
2536 connect_to(const char *host, u_short port)
2538 struct addrinfo hints, *ai, *aitop;
2539 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2543 memset(&hints, 0, sizeof(hints));
2544 hints.ai_family = IPv4or6;
2545 hints.ai_socktype = SOCK_STREAM;
2546 snprintf(strport, sizeof strport, "%d", port);
2547 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2548 error("connect_to %.100s: unknown host (%s)", host,
2549 gai_strerror(gaierr));
2552 for (ai = aitop; ai; ai = ai->ai_next) {
2553 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2555 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2556 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2557 error("connect_to: getnameinfo failed");
2560 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2562 if (ai->ai_next == NULL)
2563 error("socket: %.100s", strerror(errno));
2565 verbose("socket: %.100s", strerror(errno));
2568 if (set_nonblock(sock) == -1)
2569 fatal("%s: set_nonblock(%d)", __func__, sock);
2570 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2571 errno != EINPROGRESS) {
2572 error("connect_to %.100s port %s: %.100s", ntop, strport,
2575 continue; /* fail -- try next */
2577 break; /* success */
2580 freeaddrinfo(aitop);
2582 error("connect_to %.100s port %d: failed.", host, port);
2591 channel_connect_by_listen_address(u_short listen_port)
2595 for (i = 0; i < num_permitted_opens; i++)
2596 if (permitted_opens[i].host_to_connect != NULL &&
2597 permitted_opens[i].listen_port == listen_port)
2599 permitted_opens[i].host_to_connect,
2600 permitted_opens[i].port_to_connect);
2601 error("WARNING: Server requests forwarding for unknown listen_port %d",
2606 /* Check if connecting to that port is permitted and connect. */
2608 channel_connect_to(const char *host, u_short port)
2612 permit = all_opens_permitted;
2614 for (i = 0; i < num_permitted_opens; i++)
2615 if (permitted_opens[i].host_to_connect != NULL &&
2616 permitted_opens[i].port_to_connect == port &&
2617 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2622 logit("Received request to connect to host %.100s port %d, "
2623 "but the request was denied.", host, port);
2626 return connect_to(host, port);
2630 channel_send_window_changes(void)
2635 for (i = 0; i < channels_alloc; i++) {
2636 if (channels[i] == NULL || !channels[i]->client_tty ||
2637 channels[i]->type != SSH_CHANNEL_OPEN)
2639 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
2641 channel_request_start(i, "window-change", 0);
2642 packet_put_int(ws.ws_col);
2643 packet_put_int(ws.ws_row);
2644 packet_put_int(ws.ws_xpixel);
2645 packet_put_int(ws.ws_ypixel);
2650 /* -- X11 forwarding */
2653 * Creates an internet domain socket for listening for X11 connections.
2654 * Returns 0 and a suitable display number for the DISPLAY variable
2655 * stored in display_numberp , or -1 if an error occurs.
2658 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2659 int single_connection, u_int *display_numberp)
2662 int display_number, sock;
2664 struct addrinfo hints, *ai, *aitop;
2665 char strport[NI_MAXSERV];
2666 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2668 for (display_number = x11_display_offset;
2669 display_number < MAX_DISPLAYS;
2671 port = 6000 + display_number;
2672 memset(&hints, 0, sizeof(hints));
2673 hints.ai_family = IPv4or6;
2674 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2675 hints.ai_socktype = SOCK_STREAM;
2676 snprintf(strport, sizeof strport, "%d", port);
2677 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2678 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2681 for (ai = aitop; ai; ai = ai->ai_next) {
2682 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2684 sock = socket(ai->ai_family, ai->ai_socktype,
2687 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2688 error("socket: %.100s", strerror(errno));
2689 freeaddrinfo(aitop);
2692 debug("x11_create_display_inet: Socket family %d not supported",
2698 if (ai->ai_family == AF_INET6) {
2700 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2701 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2704 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2705 debug2("bind port %d: %.100s", port, strerror(errno));
2711 for (n = 0; n < num_socks; n++) {
2717 socks[num_socks++] = sock;
2718 #ifndef DONT_TRY_OTHER_AF
2719 if (num_socks == NUM_SOCKS)
2722 if (x11_use_localhost) {
2723 if (num_socks == NUM_SOCKS)
2730 freeaddrinfo(aitop);
2734 if (display_number >= MAX_DISPLAYS) {
2735 error("Failed to allocate internet-domain X11 display socket.");
2738 /* Start listening for connections on the socket. */
2739 for (n = 0; n < num_socks; n++) {
2741 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2742 error("listen: %.100s", strerror(errno));
2748 /* Allocate a channel for each socket. */
2749 for (n = 0; n < num_socks; n++) {
2751 nc = channel_new("x11 listener",
2752 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2753 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2754 0, "X11 inet listener", 1);
2755 nc->single_connection = single_connection;
2758 /* Return the display number for the DISPLAY environment variable. */
2759 *display_numberp = display_number;
2764 connect_local_xsocket(u_int dnr)
2767 struct sockaddr_un addr;
2769 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2771 error("socket: %.100s", strerror(errno));
2772 memset(&addr, 0, sizeof(addr));
2773 addr.sun_family = AF_UNIX;
2774 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2775 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2778 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2783 x11_connect_display(void)
2785 int display_number, sock = 0;
2786 const char *display;
2787 char buf[1024], *cp;
2788 struct addrinfo hints, *ai, *aitop;
2789 char strport[NI_MAXSERV];
2792 /* Try to open a socket for the local X server. */
2793 display = getenv("DISPLAY");
2795 error("DISPLAY not set.");
2799 * Now we decode the value of the DISPLAY variable and make a
2800 * connection to the real X server.
2804 * Check if it is a unix domain socket. Unix domain displays are in
2805 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2807 if (strncmp(display, "unix:", 5) == 0 ||
2808 display[0] == ':') {
2809 /* Connect to the unix domain socket. */
2810 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2811 error("Could not parse display number from DISPLAY: %.100s",
2815 /* Create a socket. */
2816 sock = connect_local_xsocket(display_number);
2820 /* OK, we now have a connection to the display. */
2824 * Connect to an inet socket. The DISPLAY value is supposedly
2825 * hostname:d[.s], where hostname may also be numeric IP address.
2827 strlcpy(buf, display, sizeof(buf));
2828 cp = strchr(buf, ':');
2830 error("Could not find ':' in DISPLAY: %.100s", display);
2834 /* buf now contains the host name. But first we parse the display number. */
2835 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2836 error("Could not parse display number from DISPLAY: %.100s",
2841 /* Look up the host address */
2842 memset(&hints, 0, sizeof(hints));
2843 hints.ai_family = IPv4or6;
2844 hints.ai_socktype = SOCK_STREAM;
2845 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2846 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2847 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2850 for (ai = aitop; ai; ai = ai->ai_next) {
2851 /* Create a socket. */
2852 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2854 debug2("socket: %.100s", strerror(errno));
2857 /* Connect it to the display. */
2858 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2859 debug2("connect %.100s port %d: %.100s", buf,
2860 6000 + display_number, strerror(errno));
2867 freeaddrinfo(aitop);
2869 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2878 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2879 * the remote channel number. We should do whatever we want, and respond
2880 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2884 x11_input_open(int type, u_int32_t seq, void *ctxt)
2887 int remote_id, sock = 0;
2890 debug("Received X11 open request.");
2892 remote_id = packet_get_int();
2894 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2895 remote_host = packet_get_string(NULL);
2897 remote_host = xstrdup("unknown (remote did not supply name)");
2901 /* Obtain a connection to the real X display. */
2902 sock = x11_connect_display();
2904 /* Allocate a channel for this connection. */
2905 c = channel_new("connected x11 socket",
2906 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2908 c->remote_id = remote_id;
2913 /* Send refusal to the remote host. */
2914 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2915 packet_put_int(remote_id);
2917 /* Send a confirmation to the remote host. */
2918 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2919 packet_put_int(remote_id);
2920 packet_put_int(c->self);
2925 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2927 deny_input_open(int type, u_int32_t seq, void *ctxt)
2929 int rchan = packet_get_int();
2932 case SSH_SMSG_AGENT_OPEN:
2933 error("Warning: ssh server tried agent forwarding.");
2935 case SSH_SMSG_X11_OPEN:
2936 error("Warning: ssh server tried X11 forwarding.");
2939 error("deny_input_open: type %d", type);
2942 error("Warning: this is probably a break in attempt by a malicious server.");
2943 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2944 packet_put_int(rchan);
2949 * Requests forwarding of X11 connections, generates fake authentication
2950 * data, and enables authentication spoofing.
2951 * This should be called in the client only.
2954 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
2955 const char *proto, const char *data)
2957 u_int data_len = (u_int) strlen(data) / 2;
2958 u_int i, value, len;
2966 cp = strchr(disp, ':');
2968 cp = strchr(cp, '.');
2970 screen_number = atoi(cp + 1);
2974 /* Save protocol name. */
2975 x11_saved_proto = xstrdup(proto);
2978 * Extract real authentication data and generate fake data of the
2981 x11_saved_data = xmalloc(data_len);
2982 x11_fake_data = xmalloc(data_len);
2983 for (i = 0; i < data_len; i++) {
2984 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2985 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2988 x11_saved_data[i] = value;
2989 x11_fake_data[i] = rnd & 0xff;
2992 x11_saved_data_len = data_len;
2993 x11_fake_data_len = data_len;
2995 /* Convert the fake data into hex. */
2996 len = 2 * data_len + 1;
2997 new_data = xmalloc(len);
2998 for (i = 0; i < data_len; i++)
2999 snprintf(new_data + 2 * i, len - 2 * i,
3000 "%02x", (u_char) x11_fake_data[i]);
3002 /* Send the request packet. */
3004 channel_request_start(client_session_id, "x11-req", 0);
3005 packet_put_char(0); /* XXX bool single connection */
3007 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3009 packet_put_cstring(proto);
3010 packet_put_cstring(new_data);
3011 packet_put_int(screen_number);
3013 packet_write_wait();
3018 /* -- agent forwarding */
3020 /* Sends a message to the server to request authentication fd forwarding. */
3023 auth_request_forwarding(void)
3025 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3027 packet_write_wait();