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".
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 RCSID("$OpenBSD: channels.c,v 1.123 2001/06/04 21:59:42 markus Exp $");
63 * Pointer to an array containing all allocated channels. The array is
64 * dynamically extended as needed.
66 static Channel **channels = NULL;
69 * Size of the channel array. All slots of the array must always be
70 * initialized (at least the type field); unused slots set to NULL
72 static int channels_alloc = 0;
75 * Maximum file descriptor value used in any of the channels. This is
76 * updated in channel_new.
78 static int channel_max_fd = 0;
81 /* -- tcp forwarding */
84 * Data structure for storing which hosts are permitted for forward requests.
85 * The local sides of any remote forwards are stored in this array to prevent
86 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
87 * network (which might be behind a firewall).
90 char *host_to_connect; /* Connect to 'host'. */
91 u_short port_to_connect; /* Connect to 'port'. */
92 u_short listen_port; /* Remote side should listen port number. */
95 /* List of all permitted host/port pairs to connect. */
96 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
98 /* Number of permitted host/port pairs in the array. */
99 static int num_permitted_opens = 0;
101 * If this is true, all opens are permitted. This is the case on the server
102 * on which we have to trust the client anyway, and the user could do
103 * anything after logging in anyway.
105 static int all_opens_permitted = 0;
108 /* -- X11 forwarding */
110 /* Maximum number of fake X11 displays to try. */
111 #define MAX_DISPLAYS 1000
113 /* Saved X11 authentication protocol name. */
114 static char *x11_saved_proto = NULL;
116 /* Saved X11 authentication data. This is the real data. */
117 static char *x11_saved_data = NULL;
118 static u_int x11_saved_data_len = 0;
121 * Fake X11 authentication data. This is what the server will be sending us;
122 * we should replace any occurrences of this by the real data.
124 static char *x11_fake_data = NULL;
125 static u_int x11_fake_data_len;
128 /* -- agent forwarding */
132 /* Name and directory of socket for authentication agent forwarding. */
133 static char *auth_sock_name = NULL;
134 static char *auth_sock_dir = NULL;
137 /* AF_UNSPEC or AF_INET or AF_INET6 */
141 void port_open_helper(Channel *c, char *rtype);
143 /* -- channel core */
146 channel_lookup(int id)
150 if (id < 0 || id > channels_alloc) {
151 log("channel_lookup: %d: bad id", id);
156 log("channel_lookup: %d: bad id: channel free", id);
163 * Register filedescriptors for a channel, used when allocating a channel or
164 * when the channel consumer/producer is ready, e.g. shell exec'd
168 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
169 int extusage, int nonblock)
171 /* Update the maximum file descriptor value. */
172 channel_max_fd = MAX(channel_max_fd, rfd);
173 channel_max_fd = MAX(channel_max_fd, wfd);
174 channel_max_fd = MAX(channel_max_fd, efd);
176 /* XXX set close-on-exec -markus */
180 c->sock = (rfd == wfd) ? rfd : -1;
182 c->extended_usage = extusage;
184 /* XXX ugly hack: nonblock is only set by the server */
185 if (nonblock && isatty(c->rfd)) {
186 debug("channel %d: rfd %d isatty", c->self, c->rfd);
188 if (!isatty(c->wfd)) {
189 error("channel %d: wfd %d is not a tty?",
196 /* enable nonblocking mode */
208 * Allocate a new channel object and set its type and socket. This will cause
209 * remote_name to be freed.
213 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
214 int window, int maxpack, int extusage, char *remote_name, int nonblock)
219 /* Do initial allocation if this is the first call. */
220 if (channels_alloc == 0) {
223 channels = xmalloc(channels_alloc * sizeof(Channel *));
224 for (i = 0; i < channels_alloc; i++)
227 * Kludge: arrange a call to channel_stop_listening if we
228 * terminate with fatal().
230 fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
232 /* Try to find a free slot where to put the new channel. */
233 for (found = -1, i = 0; i < channels_alloc; i++)
234 if (channels[i] == NULL) {
235 /* Found a free slot. */
240 /* There are no free slots. Take last+1 slot and expand the array. */
241 found = channels_alloc;
242 channels_alloc += 10;
243 debug2("channel: expanding %d", channels_alloc);
244 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
245 for (i = found; i < channels_alloc; i++)
248 /* Initialize and return new channel. */
249 c = channels[found] = xmalloc(sizeof(Channel));
250 buffer_init(&c->input);
251 buffer_init(&c->output);
252 buffer_init(&c->extended);
253 chan_init_iostates(c);
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 = remote_name;
264 c->remote_window = 0;
265 c->remote_maxpacket = 0;
269 c->dettach_user = NULL;
270 c->input_filter = NULL;
271 debug("channel %d: new [%s]", found, remote_name);
275 /* Close all channel fd/socket. */
278 channel_close_fds(Channel *c)
280 debug3("channel_close_fds: channel %d: r %d w %d e %d",
281 c->self, c->rfd, c->wfd, c->efd);
301 /* Free the channel and close its fd/socket. */
304 channel_free(Channel *c)
309 for (n = 0, i = 0; i < channels_alloc; i++)
312 debug("channel_free: channel %d: %s, nchannels %d", c->self,
313 c->remote_name ? c->remote_name : "???", n);
315 s = channel_open_message();
316 debug3("channel_free: status: %s", s);
319 if (c->dettach_user != NULL) {
320 debug("channel_free: channel %d: dettaching channel user", c->self);
321 c->dettach_user(c->self, NULL);
324 shutdown(c->sock, SHUT_RDWR);
325 channel_close_fds(c);
326 buffer_free(&c->input);
327 buffer_free(&c->output);
328 buffer_free(&c->extended);
329 if (c->remote_name) {
330 xfree(c->remote_name);
331 c->remote_name = NULL;
333 channels[c->self] = NULL;
339 * Stops listening for channels, and removes any unix domain sockets that we
344 channel_stop_listening()
349 for (i = 0; i < channels_alloc; i++) {
353 case SSH_CHANNEL_AUTH_SOCKET:
358 case SSH_CHANNEL_PORT_LISTENER:
359 case SSH_CHANNEL_RPORT_LISTENER:
360 case SSH_CHANNEL_X11_LISTENER:
372 * Closes the sockets/fds of all channels. This is used to close extra file
373 * descriptors after a fork.
381 for (i = 0; i < channels_alloc; i++)
382 if (channels[i] != NULL)
383 channel_close_fds(channels[i]);
387 * Returns true if no channel has too much buffered data, and false if one or
388 * more channel is overfull.
392 channel_not_very_much_buffered_data()
397 for (i = 0; i < channels_alloc; i++) {
399 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
400 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
401 debug("channel %d: big input buffer %d",
402 c->self, buffer_len(&c->input));
405 if (buffer_len(&c->output) > packet_get_maxsize()) {
406 debug("channel %d: big output buffer %d",
407 c->self, buffer_len(&c->output));
415 /* Returns true if any channel is still open. */
423 for (i = 0; i < channels_alloc; i++) {
428 case SSH_CHANNEL_X11_LISTENER:
429 case SSH_CHANNEL_PORT_LISTENER:
430 case SSH_CHANNEL_RPORT_LISTENER:
431 case SSH_CHANNEL_CLOSED:
432 case SSH_CHANNEL_AUTH_SOCKET:
433 case SSH_CHANNEL_DYNAMIC:
434 case SSH_CHANNEL_CONNECTING:
435 case SSH_CHANNEL_ZOMBIE:
437 case SSH_CHANNEL_LARVAL:
439 fatal("cannot happen: SSH_CHANNEL_LARVAL");
441 case SSH_CHANNEL_OPENING:
442 case SSH_CHANNEL_OPEN:
443 case SSH_CHANNEL_X11_OPEN:
445 case SSH_CHANNEL_INPUT_DRAINING:
446 case SSH_CHANNEL_OUTPUT_DRAINING:
448 fatal("cannot happen: OUT_DRAIN");
451 fatal("channel_still_open: bad channel type %d", c->type);
458 /* Returns the id of an open channel suitable for keepaliving */
466 for (i = 0; i < channels_alloc; i++) {
471 case SSH_CHANNEL_CLOSED:
472 case SSH_CHANNEL_DYNAMIC:
473 case SSH_CHANNEL_X11_LISTENER:
474 case SSH_CHANNEL_PORT_LISTENER:
475 case SSH_CHANNEL_RPORT_LISTENER:
476 case SSH_CHANNEL_OPENING:
477 case SSH_CHANNEL_CONNECTING:
478 case SSH_CHANNEL_ZOMBIE:
480 case SSH_CHANNEL_LARVAL:
481 case SSH_CHANNEL_AUTH_SOCKET:
482 case SSH_CHANNEL_OPEN:
483 case SSH_CHANNEL_X11_OPEN:
485 case SSH_CHANNEL_INPUT_DRAINING:
486 case SSH_CHANNEL_OUTPUT_DRAINING:
488 fatal("cannot happen: OUT_DRAIN");
491 fatal("channel_find_open: bad channel type %d", c->type);
500 * Returns a message describing the currently open forwarded connections,
501 * suitable for sending to the client. The message contains crlf pairs for
506 channel_open_message()
513 buffer_init(&buffer);
514 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
515 buffer_append(&buffer, buf, strlen(buf));
516 for (i = 0; i < channels_alloc; i++) {
521 case SSH_CHANNEL_X11_LISTENER:
522 case SSH_CHANNEL_PORT_LISTENER:
523 case SSH_CHANNEL_RPORT_LISTENER:
524 case SSH_CHANNEL_CLOSED:
525 case SSH_CHANNEL_AUTH_SOCKET:
526 case SSH_CHANNEL_ZOMBIE:
528 case SSH_CHANNEL_LARVAL:
529 case SSH_CHANNEL_OPENING:
530 case SSH_CHANNEL_CONNECTING:
531 case SSH_CHANNEL_DYNAMIC:
532 case SSH_CHANNEL_OPEN:
533 case SSH_CHANNEL_X11_OPEN:
534 case SSH_CHANNEL_INPUT_DRAINING:
535 case SSH_CHANNEL_OUTPUT_DRAINING:
536 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
537 c->self, c->remote_name,
538 c->type, c->remote_id,
539 c->istate, buffer_len(&c->input),
540 c->ostate, buffer_len(&c->output),
542 buffer_append(&buffer, buf, strlen(buf));
545 fatal("channel_open_message: bad channel type %d", c->type);
549 buffer_append(&buffer, "\0", 1);
550 cp = xstrdup(buffer_ptr(&buffer));
551 buffer_free(&buffer);
556 channel_send_open(int id)
558 Channel *c = channel_lookup(id);
560 log("channel_send_open: %d: bad id", id);
563 debug("send channel open %d", id);
564 packet_start(SSH2_MSG_CHANNEL_OPEN);
565 packet_put_cstring(c->ctype);
566 packet_put_int(c->self);
567 packet_put_int(c->local_window);
568 packet_put_int(c->local_maxpacket);
573 channel_request(int id, char *service, int wantconfirm)
575 channel_request_start(id, service, wantconfirm);
577 debug("channel request %d: %s", id, service) ;
580 channel_request_start(int id, char *service, int wantconfirm)
582 Channel *c = channel_lookup(id);
584 log("channel_request: %d: bad id", id);
587 packet_start(SSH2_MSG_CHANNEL_REQUEST);
588 packet_put_int(c->remote_id);
589 packet_put_cstring(service);
590 packet_put_char(wantconfirm);
593 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
595 Channel *c = channel_lookup(id);
597 log("channel_register_callback: %d: bad id", id);
605 channel_register_cleanup(int id, channel_callback_fn *fn)
607 Channel *c = channel_lookup(id);
609 log("channel_register_cleanup: %d: bad id", id);
612 c->dettach_user = fn;
615 channel_cancel_cleanup(int id)
617 Channel *c = channel_lookup(id);
619 log("channel_cancel_cleanup: %d: bad id", id);
622 c->dettach_user = NULL;
625 channel_register_filter(int id, channel_filter_fn *fn)
627 Channel *c = channel_lookup(id);
629 log("channel_register_filter: %d: bad id", id);
632 c->input_filter = fn;
636 channel_set_fds(int id, int rfd, int wfd, int efd,
637 int extusage, int nonblock)
639 Channel *c = channel_lookup(id);
640 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
641 fatal("channel_activate for non-larval channel %d.", id);
642 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
643 c->type = SSH_CHANNEL_OPEN;
644 /* XXX window size? */
645 c->local_window = c->local_window_max = c->local_maxpacket * 2;
646 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
647 packet_put_int(c->remote_id);
648 packet_put_int(c->local_window);
653 * 'channel_pre*' are called just before select() to add any bits relevant to
654 * channels in the select bitmasks.
657 * 'channel_post*': perform any appropriate operations for channels which
658 * have events pending.
660 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
661 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
662 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
665 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
667 FD_SET(c->sock, readset);
671 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
673 debug3("channel %d: waiting for connection", c->self);
674 FD_SET(c->sock, writeset);
678 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
680 if (buffer_len(&c->input) < packet_get_maxsize())
681 FD_SET(c->sock, readset);
682 if (buffer_len(&c->output) > 0)
683 FD_SET(c->sock, writeset);
687 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
689 /* test whether sockets are 'alive' for read/write */
690 if (c->istate == CHAN_INPUT_OPEN)
691 if (buffer_len(&c->input) < packet_get_maxsize())
692 FD_SET(c->sock, readset);
693 if (c->ostate == CHAN_OUTPUT_OPEN ||
694 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
695 if (buffer_len(&c->output) > 0) {
696 FD_SET(c->sock, writeset);
697 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
704 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
706 if (c->istate == CHAN_INPUT_OPEN &&
707 c->remote_window > 0 &&
708 buffer_len(&c->input) < c->remote_window)
709 FD_SET(c->rfd, readset);
710 if (c->ostate == CHAN_OUTPUT_OPEN ||
711 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
712 if (buffer_len(&c->output) > 0) {
713 FD_SET(c->wfd, writeset);
714 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
718 /** XXX check close conditions, too */
720 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
721 buffer_len(&c->extended) > 0)
722 FD_SET(c->efd, writeset);
723 else if (c->extended_usage == CHAN_EXTENDED_READ &&
724 buffer_len(&c->extended) < c->remote_window)
725 FD_SET(c->efd, readset);
730 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
732 if (buffer_len(&c->input) == 0) {
733 packet_start(SSH_MSG_CHANNEL_CLOSE);
734 packet_put_int(c->remote_id);
736 c->type = SSH_CHANNEL_CLOSED;
737 debug("channel %d: closing after input drain.", c->self);
742 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
744 if (buffer_len(&c->output) == 0)
747 FD_SET(c->sock, writeset);
751 * This is a special state for X11 authentication spoofing. An opened X11
752 * connection (when authentication spoofing is being done) remains in this
753 * state until the first packet has been completely read. The authentication
754 * data in that packet is then substituted by the real data if it matches the
755 * fake data, and the channel is put into normal mode.
756 * XXX All this happens at the client side.
757 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
760 x11_open_helper(Buffer *b)
763 u_int proto_len, data_len;
765 /* Check if the fixed size part of the packet is in buffer. */
766 if (buffer_len(b) < 12)
769 /* Parse the lengths of variable-length fields. */
770 ucp = (u_char *) buffer_ptr(b);
771 if (ucp[0] == 0x42) { /* Byte order MSB first. */
772 proto_len = 256 * ucp[6] + ucp[7];
773 data_len = 256 * ucp[8] + ucp[9];
774 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
775 proto_len = ucp[6] + 256 * ucp[7];
776 data_len = ucp[8] + 256 * ucp[9];
778 debug("Initial X11 packet contains bad byte order byte: 0x%x",
783 /* Check if the whole packet is in buffer. */
785 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
788 /* Check if authentication protocol matches. */
789 if (proto_len != strlen(x11_saved_proto) ||
790 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
791 debug("X11 connection uses different authentication protocol.");
794 /* Check if authentication data matches our fake data. */
795 if (data_len != x11_fake_data_len ||
796 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
797 x11_fake_data, x11_fake_data_len) != 0) {
798 debug("X11 auth data does not match fake data.");
801 /* Check fake data length */
802 if (x11_fake_data_len != x11_saved_data_len) {
803 error("X11 fake_data_len %d != saved_data_len %d",
804 x11_fake_data_len, x11_saved_data_len);
808 * Received authentication protocol and data match
809 * our fake data. Substitute the fake data with real
812 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
813 x11_saved_data, x11_saved_data_len);
818 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
820 int ret = x11_open_helper(&c->output);
822 /* Start normal processing for the channel. */
823 c->type = SSH_CHANNEL_OPEN;
824 channel_pre_open_13(c, readset, writeset);
825 } else if (ret == -1) {
827 * We have received an X11 connection that has bad
828 * authentication information.
830 log("X11 connection rejected because of wrong authentication.");
831 buffer_clear(&c->input);
832 buffer_clear(&c->output);
835 c->type = SSH_CHANNEL_CLOSED;
836 packet_start(SSH_MSG_CHANNEL_CLOSE);
837 packet_put_int(c->remote_id);
843 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
845 int ret = x11_open_helper(&c->output);
847 c->type = SSH_CHANNEL_OPEN;
849 channel_pre_open_20(c, readset, writeset);
851 channel_pre_open_15(c, readset, writeset);
852 } else if (ret == -1) {
853 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
854 chan_read_failed(c); /** force close? */
855 chan_write_failed(c);
856 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
860 /* try to decode a socks4 header */
862 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
865 int len, have, i, found;
871 struct in_addr dest_addr;
874 debug2("channel %d: decode socks4", c->self);
876 have = buffer_len(&c->input);
877 len = sizeof(s4_req);
880 p = buffer_ptr(&c->input);
881 for (found = 0, i = len; i < have; i++) {
887 /* the peer is probably sending garbage */
888 debug("channel %d: decode socks4: too long",
895 buffer_get(&c->input, (char *)&s4_req.version, 1);
896 buffer_get(&c->input, (char *)&s4_req.command, 1);
897 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
898 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
899 have = buffer_len(&c->input);
900 p = buffer_ptr(&c->input);
902 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
904 fatal("channel %d: decode socks4: len %d > have %d",
906 strlcpy(username, p, sizeof(username));
907 buffer_consume(&c->input, len);
908 buffer_consume(&c->input, 1); /* trailing '\0' */
910 host = inet_ntoa(s4_req.dest_addr);
911 strlcpy(c->path, host, sizeof(c->path));
912 c->host_port = ntohs(s4_req.dest_port);
914 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
915 c->self, host, c->host_port, s4_req.command);
917 if (s4_req.command != 1) {
918 debug("channel %d: cannot handle: socks4 cn %d",
919 c->self, s4_req.command);
922 s4_rsp.version = 0; /* vn: 0 for reply */
923 s4_rsp.command = 90; /* cd: req granted */
924 s4_rsp.dest_port = 0; /* ignored */
925 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
926 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
930 /* dynamic port forwarding */
932 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
937 have = buffer_len(&c->input);
939 debug2("channel %d: pre_dynamic: have %d", c->self, have);
940 /* buffer_dump(&c->input); */
941 /* check if the fixed size part of the packet is in buffer. */
944 FD_SET(c->sock, readset);
947 /* try to guess the protocol */
948 p = buffer_ptr(&c->input);
951 ret = channel_decode_socks4(c, readset, writeset);
959 } else if (ret == 0) {
960 debug2("channel %d: pre_dynamic: need more", c->self);
962 FD_SET(c->sock, readset);
964 /* switch to the next state */
965 c->type = SSH_CHANNEL_OPENING;
966 port_open_helper(c, "direct-tcpip");
970 /* This is our fake X11 server socket. */
972 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
975 struct sockaddr addr;
978 char buf[16384], *remote_ipaddr;
981 if (FD_ISSET(c->sock, readset)) {
982 debug("X11 connection requested.");
983 addrlen = sizeof(addr);
984 newsock = accept(c->sock, &addr, &addrlen);
986 error("accept: %.100s", strerror(errno));
989 remote_ipaddr = get_peer_ipaddr(newsock);
990 remote_port = get_peer_port(newsock);
991 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
992 remote_ipaddr, remote_port);
994 nc = channel_new("accepted x11 socket",
995 SSH_CHANNEL_OPENING, newsock, newsock, -1,
996 c->local_window_max, c->local_maxpacket,
1000 xfree(remote_ipaddr);
1004 packet_start(SSH2_MSG_CHANNEL_OPEN);
1005 packet_put_cstring("x11");
1006 packet_put_int(nc->self);
1007 packet_put_int(c->local_window_max);
1008 packet_put_int(c->local_maxpacket);
1009 /* originator ipaddr and port */
1010 packet_put_cstring(remote_ipaddr);
1011 if (datafellows & SSH_BUG_X11FWD) {
1012 debug("ssh2 x11 bug compat mode");
1014 packet_put_int(remote_port);
1018 packet_start(SSH_SMSG_X11_OPEN);
1019 packet_put_int(nc->self);
1020 if (packet_get_protocol_flags() &
1021 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1022 packet_put_string(buf, strlen(buf));
1025 xfree(remote_ipaddr);
1030 port_open_helper(Channel *c, char *rtype)
1034 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1035 u_short remote_port = get_peer_port(c->sock);
1037 direct = (strcmp(rtype, "direct-tcpip") == 0);
1039 snprintf(buf, sizeof buf,
1040 "%s: listening port %d for %.100s port %d, "
1041 "connect from %.200s port %d",
1042 rtype, c->listening_port, c->path, c->host_port,
1043 remote_ipaddr, remote_port);
1045 xfree(c->remote_name);
1046 c->remote_name = xstrdup(buf);
1049 packet_start(SSH2_MSG_CHANNEL_OPEN);
1050 packet_put_cstring(rtype);
1051 packet_put_int(c->self);
1052 packet_put_int(c->local_window_max);
1053 packet_put_int(c->local_maxpacket);
1055 /* target host, port */
1056 packet_put_cstring(c->path);
1057 packet_put_int(c->host_port);
1059 /* listen address, port */
1060 packet_put_cstring(c->path);
1061 packet_put_int(c->listening_port);
1063 /* originator host and port */
1064 packet_put_cstring(remote_ipaddr);
1065 packet_put_int(remote_port);
1068 packet_start(SSH_MSG_PORT_OPEN);
1069 packet_put_int(c->self);
1070 packet_put_cstring(c->path);
1071 packet_put_int(c->host_port);
1072 if (packet_get_protocol_flags() &
1073 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1074 packet_put_cstring(c->remote_name);
1077 xfree(remote_ipaddr);
1081 * This socket is listening for connections to a forwarded TCP/IP port.
1084 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1087 struct sockaddr addr;
1088 int newsock, nextstate;
1092 if (FD_ISSET(c->sock, readset)) {
1093 debug("Connection to port %d forwarding "
1094 "to %.100s port %d requested.",
1095 c->listening_port, c->path, c->host_port);
1097 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
1098 "forwarded-tcpip" : "direct-tcpip";
1099 nextstate = (c->host_port == 0 &&
1100 c->type != SSH_CHANNEL_RPORT_LISTENER) ?
1101 SSH_CHANNEL_DYNAMIC : SSH_CHANNEL_OPENING;
1103 addrlen = sizeof(addr);
1104 newsock = accept(c->sock, &addr, &addrlen);
1106 error("accept: %.100s", strerror(errno));
1109 nc = channel_new(rtype,
1110 nextstate, newsock, newsock, -1,
1111 c->local_window_max, c->local_maxpacket,
1112 0, xstrdup(rtype), 1);
1114 error("channel_post_port_listener: no new channel:");
1118 nc->listening_port = c->listening_port;
1119 nc->host_port = c->host_port;
1120 strlcpy(nc->path, c->path, sizeof(nc->path));
1122 if (nextstate != SSH_CHANNEL_DYNAMIC)
1123 port_open_helper(nc, rtype);
1128 * This is the authentication agent socket listening for connections from
1132 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1137 struct sockaddr addr;
1140 if (FD_ISSET(c->sock, readset)) {
1141 addrlen = sizeof(addr);
1142 newsock = accept(c->sock, &addr, &addrlen);
1144 error("accept from auth socket: %.100s", strerror(errno));
1147 name = xstrdup("accepted auth socket");
1148 nc = channel_new("accepted auth socket",
1149 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1150 c->local_window_max, c->local_maxpacket,
1153 error("channel_post_auth_listener: channel_new failed");
1158 packet_start(SSH2_MSG_CHANNEL_OPEN);
1159 packet_put_cstring("auth-agent@openssh.com");
1160 packet_put_int(nc->self);
1161 packet_put_int(c->local_window_max);
1162 packet_put_int(c->local_maxpacket);
1164 packet_start(SSH_SMSG_AGENT_OPEN);
1165 packet_put_int(nc->self);
1172 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1175 int sz = sizeof(err);
1177 if (FD_ISSET(c->sock, writeset)) {
1178 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1181 error("getsockopt SO_ERROR failed");
1184 debug("channel %d: connected", c->self);
1185 c->type = SSH_CHANNEL_OPEN;
1187 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1188 packet_put_int(c->remote_id);
1189 packet_put_int(c->self);
1190 packet_put_int(c->local_window);
1191 packet_put_int(c->local_maxpacket);
1193 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1194 packet_put_int(c->remote_id);
1195 packet_put_int(c->self);
1198 debug("channel %d: not connected: %s",
1199 c->self, strerror(err));
1201 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1202 packet_put_int(c->remote_id);
1203 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1204 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1205 packet_put_cstring(strerror(err));
1206 packet_put_cstring("");
1209 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1210 packet_put_int(c->remote_id);
1219 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1225 FD_ISSET(c->rfd, readset)) {
1226 len = read(c->rfd, buf, sizeof(buf));
1227 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1230 debug("channel %d: read<=0 rfd %d len %d",
1231 c->self, c->rfd, len);
1232 if (c->type != SSH_CHANNEL_OPEN) {
1233 debug("channel %d: not open", c->self);
1236 } else if (compat13) {
1237 buffer_consume(&c->output, buffer_len(&c->output));
1238 c->type = SSH_CHANNEL_INPUT_DRAINING;
1239 debug("channel %d: input draining.", c->self);
1241 chan_read_failed(c);
1245 if(c->input_filter != NULL) {
1246 if (c->input_filter(c, buf, len) == -1) {
1247 debug("channel %d: filter stops", c->self);
1248 chan_read_failed(c);
1251 buffer_append(&c->input, buf, len);
1257 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1262 /* Send buffered output data to the socket. */
1264 FD_ISSET(c->wfd, writeset) &&
1265 buffer_len(&c->output) > 0) {
1266 len = write(c->wfd, buffer_ptr(&c->output),
1267 buffer_len(&c->output));
1268 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1271 if (c->type != SSH_CHANNEL_OPEN) {
1272 debug("channel %d: not open", c->self);
1275 } else if (compat13) {
1276 buffer_consume(&c->output, buffer_len(&c->output));
1277 debug("channel %d: input draining.", c->self);
1278 c->type = SSH_CHANNEL_INPUT_DRAINING;
1280 chan_write_failed(c);
1284 if (compat20 && c->isatty) {
1285 if (tcgetattr(c->wfd, &tio) == 0 &&
1286 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1288 * Simulate echo to reduce the impact of
1289 * traffic analysis. We need to match the
1290 * size of a SSH2_MSG_CHANNEL_DATA message
1291 * (4 byte channel id + data)
1293 packet_send_ignore(4 + len);
1297 buffer_consume(&c->output, len);
1298 if (compat20 && len > 0) {
1299 c->local_consumed += len;
1305 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1310 /** XXX handle drain efd, too */
1312 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1313 FD_ISSET(c->efd, writeset) &&
1314 buffer_len(&c->extended) > 0) {
1315 len = write(c->efd, buffer_ptr(&c->extended),
1316 buffer_len(&c->extended));
1317 debug2("channel %d: written %d to efd %d",
1318 c->self, len, c->efd);
1319 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1322 debug2("channel %d: closing write-efd %d",
1327 buffer_consume(&c->extended, len);
1328 c->local_consumed += len;
1330 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1331 FD_ISSET(c->efd, readset)) {
1332 len = read(c->efd, buf, sizeof(buf));
1333 debug2("channel %d: read %d from efd %d",
1334 c->self, len, c->efd);
1335 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1338 debug2("channel %d: closing read-efd %d",
1343 buffer_append(&c->extended, buf, len);
1350 channel_check_window(Channel *c)
1352 if (c->type == SSH_CHANNEL_OPEN &&
1353 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1354 c->local_window < c->local_window_max/2 &&
1355 c->local_consumed > 0) {
1356 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1357 packet_put_int(c->remote_id);
1358 packet_put_int(c->local_consumed);
1360 debug2("channel %d: window %d sent adjust %d",
1361 c->self, c->local_window,
1363 c->local_window += c->local_consumed;
1364 c->local_consumed = 0;
1370 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1372 channel_handle_rfd(c, readset, writeset);
1373 channel_handle_wfd(c, readset, writeset);
1377 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1379 channel_handle_rfd(c, readset, writeset);
1380 channel_handle_wfd(c, readset, writeset);
1381 channel_handle_efd(c, readset, writeset);
1383 channel_check_window(c);
1387 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1390 /* Send buffered output data to the socket. */
1391 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1392 len = write(c->sock, buffer_ptr(&c->output),
1393 buffer_len(&c->output));
1395 buffer_consume(&c->output, buffer_len(&c->output));
1397 buffer_consume(&c->output, len);
1402 channel_handler_init_20(void)
1404 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1405 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1406 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1407 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1408 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1409 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1410 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1411 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1413 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1414 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1415 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1416 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1417 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1418 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1419 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1423 channel_handler_init_13(void)
1425 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1426 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1427 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1428 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1429 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1430 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1431 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1432 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1433 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1435 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1436 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1437 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1438 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1439 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1440 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1441 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1445 channel_handler_init_15(void)
1447 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1448 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1449 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1450 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1451 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1452 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1453 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1455 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1456 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1457 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1458 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1459 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1460 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1464 channel_handler_init(void)
1467 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1468 channel_pre[i] = NULL;
1469 channel_post[i] = NULL;
1472 channel_handler_init_20();
1474 channel_handler_init_13();
1476 channel_handler_init_15();
1480 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1482 static int did_init = 0;
1487 channel_handler_init();
1490 for (i = 0; i < channels_alloc; i++) {
1494 if (ftab[c->type] != NULL)
1495 (*ftab[c->type])(c, readset, writeset);
1496 if (chan_is_dead(c)) {
1498 * we have to remove the fd's from the select mask
1499 * before the channels are free'd and the fd's are
1503 FD_CLR(c->wfd, writeset);
1505 FD_CLR(c->rfd, readset);
1507 if (c->extended_usage == CHAN_EXTENDED_READ)
1508 FD_CLR(c->efd, readset);
1509 if (c->extended_usage == CHAN_EXTENDED_WRITE)
1510 FD_CLR(c->efd, writeset);
1518 * Allocate/update select bitmasks and add any bits relevant to channels in
1522 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1528 n = MAX(*maxfdp, channel_max_fd);
1530 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1531 if (*readsetp == NULL || n > *maxfdp) {
1536 *readsetp = xmalloc(sz);
1537 *writesetp = xmalloc(sz);
1540 memset(*readsetp, 0, sz);
1541 memset(*writesetp, 0, sz);
1544 channel_handler(channel_pre, *readsetp, *writesetp);
1548 * After select, perform any appropriate operations for channels which have
1552 channel_after_select(fd_set * readset, fd_set * writeset)
1554 channel_handler(channel_post, readset, writeset);
1558 /* If there is data to send to the connection, enqueue some of it now. */
1561 channel_output_poll()
1566 for (i = 0; i < channels_alloc; i++) {
1572 * We are only interested in channels that can have buffered
1576 if (c->type != SSH_CHANNEL_OPEN &&
1577 c->type != SSH_CHANNEL_INPUT_DRAINING)
1580 if (c->type != SSH_CHANNEL_OPEN)
1584 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1585 /* XXX is this true? */
1586 debug2("channel %d: no data after CLOSE", c->self);
1590 /* Get the amount of buffered data for this channel. */
1591 if ((c->istate == CHAN_INPUT_OPEN ||
1592 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1593 (len = buffer_len(&c->input)) > 0) {
1595 * Send some data for the other side over the secure
1599 if (len > c->remote_window)
1600 len = c->remote_window;
1601 if (len > c->remote_maxpacket)
1602 len = c->remote_maxpacket;
1604 if (packet_is_interactive()) {
1608 /* Keep the packets at reasonable size. */
1609 if (len > packet_get_maxsize()/2)
1610 len = packet_get_maxsize()/2;
1614 packet_start(compat20 ?
1615 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1616 packet_put_int(c->remote_id);
1617 packet_put_string(buffer_ptr(&c->input), len);
1619 buffer_consume(&c->input, len);
1620 c->remote_window -= len;
1622 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1624 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1626 * input-buffer is empty and read-socket shutdown:
1627 * tell peer, that we will not send more data: send IEOF
1631 /* Send extended data, i.e. stderr */
1633 c->remote_window > 0 &&
1634 (len = buffer_len(&c->extended)) > 0 &&
1635 c->extended_usage == CHAN_EXTENDED_READ) {
1636 debug2("channel %d: rwin %d elen %d euse %d",
1637 c->self, c->remote_window, buffer_len(&c->extended),
1639 if (len > c->remote_window)
1640 len = c->remote_window;
1641 if (len > c->remote_maxpacket)
1642 len = c->remote_maxpacket;
1643 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1644 packet_put_int(c->remote_id);
1645 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1646 packet_put_string(buffer_ptr(&c->extended), len);
1648 buffer_consume(&c->extended, len);
1649 c->remote_window -= len;
1650 debug2("channel %d: sent ext data %d", c->self, len);
1656 /* -- protocol input */
1659 channel_input_data(int type, int plen, void *ctxt)
1666 /* Get the channel number and verify it. */
1667 id = packet_get_int();
1668 c = channel_lookup(id);
1670 packet_disconnect("Received data for nonexistent channel %d.", id);
1672 /* Ignore any data for non-open channels (might happen on close) */
1673 if (c->type != SSH_CHANNEL_OPEN &&
1674 c->type != SSH_CHANNEL_X11_OPEN)
1677 /* same for protocol 1.5 if output end is no longer open */
1678 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1682 data = packet_get_string(&data_len);
1686 if (data_len > c->local_maxpacket) {
1687 log("channel %d: rcvd big packet %d, maxpack %d",
1688 c->self, data_len, c->local_maxpacket);
1690 if (data_len > c->local_window) {
1691 log("channel %d: rcvd too much data %d, win %d",
1692 c->self, data_len, c->local_window);
1696 c->local_window -= data_len;
1698 packet_integrity_check(plen, 4 + 4 + data_len, type);
1700 buffer_append(&c->output, data, data_len);
1705 channel_input_extended_data(int type, int plen, void *ctxt)
1713 /* Get the channel number and verify it. */
1714 id = packet_get_int();
1715 c = channel_lookup(id);
1718 packet_disconnect("Received extended_data for bad channel %d.", id);
1719 if (c->type != SSH_CHANNEL_OPEN) {
1720 log("channel %d: ext data for non open", id);
1723 tcode = packet_get_int();
1725 c->extended_usage != CHAN_EXTENDED_WRITE ||
1726 tcode != SSH2_EXTENDED_DATA_STDERR) {
1727 log("channel %d: bad ext data", c->self);
1730 data = packet_get_string(&data_len);
1732 if (data_len > c->local_window) {
1733 log("channel %d: rcvd too much extended_data %d, win %d",
1734 c->self, data_len, c->local_window);
1738 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1739 c->local_window -= data_len;
1740 buffer_append(&c->extended, data, data_len);
1745 channel_input_ieof(int type, int plen, void *ctxt)
1750 packet_integrity_check(plen, 4, type);
1752 id = packet_get_int();
1753 c = channel_lookup(id);
1755 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1760 channel_input_close(int type, int plen, void *ctxt)
1765 packet_integrity_check(plen, 4, type);
1767 id = packet_get_int();
1768 c = channel_lookup(id);
1770 packet_disconnect("Received close for nonexistent channel %d.", id);
1773 * Send a confirmation that we have closed the channel and no more
1774 * data is coming for it.
1776 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1777 packet_put_int(c->remote_id);
1781 * If the channel is in closed state, we have sent a close request,
1782 * and the other side will eventually respond with a confirmation.
1783 * Thus, we cannot free the channel here, because then there would be
1784 * no-one to receive the confirmation. The channel gets freed when
1785 * the confirmation arrives.
1787 if (c->type != SSH_CHANNEL_CLOSED) {
1789 * Not a closed channel - mark it as draining, which will
1790 * cause it to be freed later.
1792 buffer_consume(&c->input, buffer_len(&c->input));
1793 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1797 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1799 channel_input_oclose(int type, int plen, void *ctxt)
1801 int id = packet_get_int();
1802 Channel *c = channel_lookup(id);
1803 packet_integrity_check(plen, 4, type);
1805 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1806 chan_rcvd_oclose(c);
1810 channel_input_close_confirmation(int type, int plen, void *ctxt)
1812 int id = packet_get_int();
1813 Channel *c = channel_lookup(id);
1817 packet_disconnect("Received close confirmation for "
1818 "out-of-range channel %d.", id);
1819 if (c->type != SSH_CHANNEL_CLOSED)
1820 packet_disconnect("Received close confirmation for "
1821 "non-closed channel %d (type %d).", id, c->type);
1826 channel_input_open_confirmation(int type, int plen, void *ctxt)
1832 packet_integrity_check(plen, 4 + 4, type);
1834 id = packet_get_int();
1835 c = channel_lookup(id);
1837 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1838 packet_disconnect("Received open confirmation for "
1839 "non-opening channel %d.", id);
1840 remote_id = packet_get_int();
1841 /* Record the remote channel number and mark that the channel is now open. */
1842 c->remote_id = remote_id;
1843 c->type = SSH_CHANNEL_OPEN;
1846 c->remote_window = packet_get_int();
1847 c->remote_maxpacket = packet_get_int();
1849 if (c->cb_fn != NULL && c->cb_event == type) {
1850 debug2("callback start");
1851 c->cb_fn(c->self, c->cb_arg);
1852 debug2("callback done");
1854 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1855 c->remote_window, c->remote_maxpacket);
1860 reason2txt(int reason)
1863 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1864 return "administratively prohibited";
1865 case SSH2_OPEN_CONNECT_FAILED:
1866 return "connect failed";
1867 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1868 return "unknown channel type";
1869 case SSH2_OPEN_RESOURCE_SHORTAGE:
1870 return "resource shortage";
1872 return "unknown reason";
1876 channel_input_open_failure(int type, int plen, void *ctxt)
1879 char *msg = NULL, *lang = NULL;
1883 packet_integrity_check(plen, 4, type);
1885 id = packet_get_int();
1886 c = channel_lookup(id);
1888 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1889 packet_disconnect("Received open failure for "
1890 "non-opening channel %d.", id);
1892 reason = packet_get_int();
1893 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1894 msg = packet_get_string(NULL);
1895 lang = packet_get_string(NULL);
1898 log("channel %d: open failed: %s%s%s", id,
1899 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1905 /* Free the channel. This will also close the socket. */
1910 channel_input_channel_request(int type, int plen, void *ctxt)
1915 id = packet_get_int();
1916 c = channel_lookup(id);
1919 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1920 packet_disconnect("Received request for "
1921 "non-open channel %d.", id);
1922 if (c->cb_fn != NULL && c->cb_event == type) {
1923 debug2("callback start");
1924 c->cb_fn(c->self, c->cb_arg);
1925 debug2("callback done");
1927 char *service = packet_get_string(NULL);
1928 debug("channel %d: rcvd request for %s", c->self, service);
1929 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1935 channel_input_window_adjust(int type, int plen, void *ctxt)
1943 /* Get the channel number and verify it. */
1944 id = packet_get_int();
1945 c = channel_lookup(id);
1947 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1948 log("Received window adjust for "
1949 "non-open channel %d.", id);
1952 adjust = packet_get_int();
1954 debug2("channel %d: rcvd adjust %d", id, adjust);
1955 c->remote_window += adjust;
1959 channel_input_port_open(int type, int plen, void *ctxt)
1963 char *host, *originator_string;
1964 int remote_id, sock = -1;
1966 remote_id = packet_get_int();
1967 host = packet_get_string(NULL);
1968 host_port = packet_get_int();
1970 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
1971 originator_string = packet_get_string(NULL);
1973 originator_string = xstrdup("unknown (remote did not supply name)");
1976 sock = channel_connect_to(host, host_port);
1978 c = channel_new("connected socket",
1979 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
1980 originator_string, 1);
1982 error("channel_input_port_open: channel_new failed");
1985 c->remote_id = remote_id;
1989 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1990 packet_put_int(remote_id);
1997 /* -- tcp forwarding */
2000 * Initiate forwarding of connections to local port "port" through the secure
2001 * channel to host:port from remote side.
2004 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2005 u_short port_to_connect, int gateway_ports)
2007 return channel_request_forwarding(
2009 host_to_connect, port_to_connect,
2010 gateway_ports, /*remote_fwd*/ 0);
2014 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2015 * (SSH_CHANNEL_RPORT_LISTENER).
2018 channel_request_forwarding(
2019 const char *listen_address, u_short listen_port,
2020 const char *host_to_connect, u_short port_to_connect,
2021 int gateway_ports, int remote_fwd)
2024 int success, sock, on = 1, type;
2025 struct addrinfo hints, *ai, *aitop;
2026 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2028 struct linger linger;
2033 host = listen_address;
2034 type = SSH_CHANNEL_RPORT_LISTENER;
2036 host = host_to_connect;
2037 type = SSH_CHANNEL_PORT_LISTENER;
2040 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2041 error("Forward host name too long.");
2045 /* XXX listen_address is currently ignored */
2047 * getaddrinfo returns a loopback address if the hostname is
2048 * set to NULL and hints.ai_flags is not AI_PASSIVE
2050 memset(&hints, 0, sizeof(hints));
2051 hints.ai_family = IPv4or6;
2052 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2053 hints.ai_socktype = SOCK_STREAM;
2054 snprintf(strport, sizeof strport, "%d", listen_port);
2055 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2056 packet_disconnect("getaddrinfo: fatal error");
2058 for (ai = aitop; ai; ai = ai->ai_next) {
2059 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2061 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2062 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2063 error("channel_request_forwarding: getnameinfo failed");
2066 /* Create a port to listen for the host. */
2067 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2069 /* this is no error since kernel may not support ipv6 */
2070 verbose("socket: %.100s", strerror(errno));
2074 * Set socket options. We would like the socket to disappear
2075 * as soon as it has been closed for whatever reason.
2077 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2079 linger.l_linger = 5;
2080 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2081 debug("Local forwarding listening on %s port %s.", ntop, strport);
2083 /* Bind the socket to the address. */
2084 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2085 /* address can be in use ipv6 address is already bound */
2087 error("bind: %.100s", strerror(errno));
2089 verbose("bind: %.100s", strerror(errno));
2094 /* Start listening for connections on the socket. */
2095 if (listen(sock, 5) < 0) {
2096 error("listen: %.100s", strerror(errno));
2100 /* Allocate a channel number for the socket. */
2101 c = channel_new("port listener", type, sock, sock, -1,
2102 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2103 0, xstrdup("port listener"), 1);
2105 error("channel_request_forwarding: channel_new failed");
2109 strlcpy(c->path, host, sizeof(c->path));
2110 c->host_port = port_to_connect;
2111 c->listening_port = listen_port;
2115 error("channel_request_forwarding: cannot listen to port: %d",
2117 freeaddrinfo(aitop);
2122 * Initiate forwarding of connections to port "port" on remote host through
2123 * the secure channel to host:port from local side.
2127 channel_request_remote_forwarding(u_short listen_port,
2128 const char *host_to_connect, u_short port_to_connect)
2130 int payload_len, type, success = 0;
2132 /* Record locally that connection to this host/port is permitted. */
2133 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2134 fatal("channel_request_remote_forwarding: too many forwards");
2136 /* Send the forward request to the remote side. */
2138 const char *address_to_bind = "0.0.0.0";
2139 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2140 packet_put_cstring("tcpip-forward");
2141 packet_put_char(0); /* boolean: want reply */
2142 packet_put_cstring(address_to_bind);
2143 packet_put_int(listen_port);
2145 packet_write_wait();
2146 /* Assume that server accepts the request */
2149 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2150 packet_put_int(listen_port);
2151 packet_put_cstring(host_to_connect);
2152 packet_put_int(port_to_connect);
2154 packet_write_wait();
2156 /* Wait for response from the remote side. */
2157 type = packet_read(&payload_len);
2159 case SSH_SMSG_SUCCESS:
2162 case SSH_SMSG_FAILURE:
2163 log("Warning: Server denied remote port forwarding.");
2166 /* Unknown packet */
2167 packet_disconnect("Protocol error for port forward request:"
2168 "received packet type %d.", type);
2172 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2173 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2174 permitted_opens[num_permitted_opens].listen_port = listen_port;
2175 num_permitted_opens++;
2180 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2181 * listening for the port, and sends back a success reply (or disconnect
2182 * message if there was an error). This never returns if there was an error.
2186 channel_input_port_forward_request(int is_root, int gateway_ports)
2188 u_short port, host_port;
2191 /* Get arguments from the packet. */
2192 port = packet_get_int();
2193 hostname = packet_get_string(NULL);
2194 host_port = packet_get_int();
2198 * Check that an unprivileged user is not trying to forward a
2201 if (port < IPPORT_RESERVED && !is_root)
2202 packet_disconnect("Requested forwarding of port %d but user is not root.",
2205 /* Initiate forwarding */
2206 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2208 /* Free the argument string. */
2213 * Permits opening to any host/port if permitted_opens[] is empty. This is
2214 * usually called by the server, because the user could connect to any port
2215 * anyway, and the server has no way to know but to trust the client anyway.
2218 channel_permit_all_opens()
2220 if (num_permitted_opens == 0)
2221 all_opens_permitted = 1;
2225 channel_add_permitted_opens(char *host, int port)
2227 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2228 fatal("channel_request_remote_forwarding: too many forwards");
2229 debug("allow port forwarding to host %s port %d", host, port);
2231 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2232 permitted_opens[num_permitted_opens].port_to_connect = port;
2233 num_permitted_opens++;
2235 all_opens_permitted = 0;
2239 channel_clear_permitted_opens(void)
2243 for (i = 0; i < num_permitted_opens; i++)
2244 xfree(permitted_opens[i].host_to_connect);
2245 num_permitted_opens = 0;
2250 /* return socket to remote host, port */
2252 connect_to(const char *host, u_short port)
2254 struct addrinfo hints, *ai, *aitop;
2255 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2259 memset(&hints, 0, sizeof(hints));
2260 hints.ai_family = IPv4or6;
2261 hints.ai_socktype = SOCK_STREAM;
2262 snprintf(strport, sizeof strport, "%d", port);
2263 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2264 error("connect_to %.100s: unknown host (%s)", host,
2265 gai_strerror(gaierr));
2268 for (ai = aitop; ai; ai = ai->ai_next) {
2269 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2271 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2272 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2273 error("connect_to: getnameinfo failed");
2276 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2278 error("socket: %.100s", strerror(errno));
2281 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2282 fatal("connect_to: F_SETFL: %s", strerror(errno));
2283 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2284 errno != EINPROGRESS) {
2285 error("connect_to %.100s port %s: %.100s", ntop, strport,
2288 continue; /* fail -- try next */
2290 break; /* success */
2293 freeaddrinfo(aitop);
2295 error("connect_to %.100s port %d: failed.", host, port);
2303 channel_connect_by_listen_adress(u_short listen_port)
2307 for (i = 0; i < num_permitted_opens; i++)
2308 if (permitted_opens[i].listen_port == listen_port)
2310 permitted_opens[i].host_to_connect,
2311 permitted_opens[i].port_to_connect);
2312 error("WARNING: Server requests forwarding for unknown listen_port %d",
2317 /* Check if connecting to that port is permitted and connect. */
2319 channel_connect_to(const char *host, u_short port)
2323 permit = all_opens_permitted;
2325 for (i = 0; i < num_permitted_opens; i++)
2326 if (permitted_opens[i].port_to_connect == port &&
2327 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2332 log("Received request to connect to host %.100s port %d, "
2333 "but the request was denied.", host, port);
2336 return connect_to(host, port);
2339 /* -- X11 forwarding */
2342 * Creates an internet domain socket for listening for X11 connections.
2343 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2347 x11_create_display_inet(int screen_number, int x11_display_offset)
2349 int display_number, sock;
2351 struct addrinfo hints, *ai, *aitop;
2352 char strport[NI_MAXSERV];
2353 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2355 char hostname[MAXHOSTNAMELEN];
2357 for (display_number = x11_display_offset;
2358 display_number < MAX_DISPLAYS;
2360 port = 6000 + display_number;
2361 memset(&hints, 0, sizeof(hints));
2362 hints.ai_family = IPv4or6;
2363 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2364 hints.ai_socktype = SOCK_STREAM;
2365 snprintf(strport, sizeof strport, "%d", port);
2366 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2367 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2370 for (ai = aitop; ai; ai = ai->ai_next) {
2371 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2373 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2375 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2376 error("socket: %.100s", strerror(errno));
2379 debug("x11_create_display_inet: Socket family %d not supported",
2384 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2385 debug("bind port %d: %.100s", port, strerror(errno));
2386 shutdown(sock, SHUT_RDWR);
2392 for (n = 0; n < num_socks; n++) {
2393 shutdown(socks[n], SHUT_RDWR);
2399 socks[num_socks++] = sock;
2400 #ifndef DONT_TRY_OTHER_AF
2401 if (num_socks == NUM_SOCKS)
2407 freeaddrinfo(aitop);
2411 if (display_number >= MAX_DISPLAYS) {
2412 error("Failed to allocate internet-domain X11 display socket.");
2415 /* Start listening for connections on the socket. */
2416 for (n = 0; n < num_socks; n++) {
2418 if (listen(sock, 5) < 0) {
2419 error("listen: %.100s", strerror(errno));
2420 shutdown(sock, SHUT_RDWR);
2426 /* Set up a suitable value for the DISPLAY variable. */
2427 if (gethostname(hostname, sizeof(hostname)) < 0)
2428 fatal("gethostname: %.100s", strerror(errno));
2430 #ifdef IPADDR_IN_DISPLAY
2432 * HPUX detects the local hostname in the DISPLAY variable and tries
2433 * to set up a shared memory connection to the server, which it
2434 * incorrectly supposes to be local.
2436 * The workaround - as used in later $$H and other programs - is
2437 * is to set display to the host's IP address.
2441 struct in_addr my_addr;
2443 he = gethostbyname(hostname);
2445 error("[X11-broken-fwd-hostname-workaround] Could not get "
2446 "IP address for hostname %s.", hostname);
2448 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2449 "Could not get IP address for hostname %s.", hostname);
2451 shutdown(sock, SHUT_RDWR);
2457 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2459 /* Set DISPLAY to <ip address>:screen.display */
2460 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2461 display_number, screen_number);
2463 #else /* IPADDR_IN_DISPLAY */
2464 /* Just set DISPLAY to hostname:screen.display */
2465 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2466 display_number, screen_number);
2467 #endif /* IPADDR_IN_DISPLAY */
2469 /* Allocate a channel for each socket. */
2470 for (n = 0; n < num_socks; n++) {
2472 (void) channel_new("x11 listener",
2473 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2474 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2475 0, xstrdup("X11 inet listener"), 1);
2478 /* Return a suitable value for the DISPLAY environment variable. */
2479 return xstrdup(display);
2483 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2488 connect_local_xsocket(u_int dnr)
2490 static const char *const x_sockets[] = {
2492 "/var/X/.X11-unix/X" "%u",
2493 "/usr/spool/sockets/X11/" "%u",
2497 struct sockaddr_un addr;
2498 const char *const * path;
2500 for (path = x_sockets; *path; ++path) {
2501 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2503 error("socket: %.100s", strerror(errno));
2504 memset(&addr, 0, sizeof(addr));
2505 addr.sun_family = AF_UNIX;
2506 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2507 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2511 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2516 x11_connect_display(void)
2518 int display_number, sock = 0;
2519 const char *display;
2520 char buf[1024], *cp;
2521 struct addrinfo hints, *ai, *aitop;
2522 char strport[NI_MAXSERV];
2525 /* Try to open a socket for the local X server. */
2526 display = getenv("DISPLAY");
2528 error("DISPLAY not set.");
2532 * Now we decode the value of the DISPLAY variable and make a
2533 * connection to the real X server.
2537 * Check if it is a unix domain socket. Unix domain displays are in
2538 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2540 if (strncmp(display, "unix:", 5) == 0 ||
2541 display[0] == ':') {
2542 /* Connect to the unix domain socket. */
2543 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2544 error("Could not parse display number from DISPLAY: %.100s",
2548 /* Create a socket. */
2549 sock = connect_local_xsocket(display_number);
2553 /* OK, we now have a connection to the display. */
2557 * Connect to an inet socket. The DISPLAY value is supposedly
2558 * hostname:d[.s], where hostname may also be numeric IP address.
2560 strncpy(buf, display, sizeof(buf));
2561 buf[sizeof(buf) - 1] = 0;
2562 cp = strchr(buf, ':');
2564 error("Could not find ':' in DISPLAY: %.100s", display);
2568 /* buf now contains the host name. But first we parse the display number. */
2569 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2570 error("Could not parse display number from DISPLAY: %.100s",
2575 /* Look up the host address */
2576 memset(&hints, 0, sizeof(hints));
2577 hints.ai_family = IPv4or6;
2578 hints.ai_socktype = SOCK_STREAM;
2579 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2580 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2581 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2584 for (ai = aitop; ai; ai = ai->ai_next) {
2585 /* Create a socket. */
2586 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2588 debug("socket: %.100s", strerror(errno));
2591 /* Connect it to the display. */
2592 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2593 debug("connect %.100s port %d: %.100s", buf,
2594 6000 + display_number, strerror(errno));
2601 freeaddrinfo(aitop);
2603 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2611 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2612 * the remote channel number. We should do whatever we want, and respond
2613 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2617 x11_input_open(int type, int plen, void *ctxt)
2620 int remote_id, sock = 0;
2623 debug("Received X11 open request.");
2625 remote_id = packet_get_int();
2627 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2628 remote_host = packet_get_string(NULL);
2630 remote_host = xstrdup("unknown (remote did not supply name)");
2634 /* Obtain a connection to the real X display. */
2635 sock = x11_connect_display();
2637 /* Allocate a channel for this connection. */
2638 c = channel_new("connected x11 socket",
2639 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2642 error("x11_input_open: channel_new failed");
2645 c->remote_id = remote_id;
2649 /* Send refusal to the remote host. */
2650 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2651 packet_put_int(remote_id);
2653 /* Send a confirmation to the remote host. */
2654 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2655 packet_put_int(remote_id);
2656 packet_put_int(c->self);
2661 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2663 deny_input_open(int type, int plen, void *ctxt)
2665 int rchan = packet_get_int();
2667 case SSH_SMSG_AGENT_OPEN:
2668 error("Warning: ssh server tried agent forwarding.");
2670 case SSH_SMSG_X11_OPEN:
2671 error("Warning: ssh server tried X11 forwarding.");
2674 error("deny_input_open: type %d plen %d", type, plen);
2677 error("Warning: this is probably a break in attempt by a malicious server.");
2678 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2679 packet_put_int(rchan);
2684 * Requests forwarding of X11 connections, generates fake authentication
2685 * data, and enables authentication spoofing.
2686 * This should be called in the client only.
2689 x11_request_forwarding_with_spoofing(int client_session_id,
2690 const char *proto, const char *data)
2692 u_int data_len = (u_int) strlen(data) / 2;
2693 u_int i, value, len;
2699 cp = getenv("DISPLAY");
2701 cp = strchr(cp, ':');
2703 cp = strchr(cp, '.');
2705 screen_number = atoi(cp + 1);
2709 /* Save protocol name. */
2710 x11_saved_proto = xstrdup(proto);
2713 * Extract real authentication data and generate fake data of the
2716 x11_saved_data = xmalloc(data_len);
2717 x11_fake_data = xmalloc(data_len);
2718 for (i = 0; i < data_len; i++) {
2719 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2720 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2722 rand = arc4random();
2723 x11_saved_data[i] = value;
2724 x11_fake_data[i] = rand & 0xff;
2727 x11_saved_data_len = data_len;
2728 x11_fake_data_len = data_len;
2730 /* Convert the fake data into hex. */
2731 len = 2 * data_len + 1;
2732 new_data = xmalloc(len);
2733 for (i = 0; i < data_len; i++)
2734 snprintf(new_data + 2 * i, len - 2 * i,
2735 "%02x", (u_char) x11_fake_data[i]);
2737 /* Send the request packet. */
2739 channel_request_start(client_session_id, "x11-req", 0);
2740 packet_put_char(0); /* XXX bool single connection */
2742 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2744 packet_put_cstring(proto);
2745 packet_put_cstring(new_data);
2746 packet_put_int(screen_number);
2748 packet_write_wait();
2753 /* -- agent forwarding */
2755 /* Sends a message to the server to request authentication fd forwarding. */
2758 auth_request_forwarding()
2760 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2762 packet_write_wait();
2766 * Returns the name of the forwarded authentication socket. Returns NULL if
2767 * there is no forwarded authentication socket. The returned value points to
2772 auth_get_socket_name()
2774 return auth_sock_name;
2777 /* removes the agent forwarding socket */
2780 auth_sock_cleanup_proc(void *_pw)
2782 struct passwd *pw = _pw;
2784 if (auth_sock_name) {
2785 temporarily_use_uid(pw);
2786 unlink(auth_sock_name);
2787 rmdir(auth_sock_dir);
2788 auth_sock_name = NULL;
2794 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2795 * This starts forwarding authentication requests.
2799 auth_input_request_forwarding(struct passwd * pw)
2803 struct sockaddr_un sunaddr;
2805 if (auth_get_socket_name() != NULL) {
2806 error("authentication forwarding requested twice.");
2810 /* Temporarily drop privileged uid for mkdir/bind. */
2811 temporarily_use_uid(pw);
2813 /* Allocate a buffer for the socket name, and format the name. */
2814 auth_sock_name = xmalloc(MAXPATHLEN);
2815 auth_sock_dir = xmalloc(MAXPATHLEN);
2816 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2818 /* Create private directory for socket */
2819 if (mkdtemp(auth_sock_dir) == NULL) {
2820 packet_send_debug("Agent forwarding disabled: "
2821 "mkdtemp() failed: %.100s", strerror(errno));
2823 xfree(auth_sock_name);
2824 xfree(auth_sock_dir);
2825 auth_sock_name = NULL;
2826 auth_sock_dir = NULL;
2829 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2830 auth_sock_dir, (int) getpid());
2832 /* delete agent socket on fatal() */
2833 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2835 /* Create the socket. */
2836 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2838 packet_disconnect("socket: %.100s", strerror(errno));
2840 /* Bind it to the name. */
2841 memset(&sunaddr, 0, sizeof(sunaddr));
2842 sunaddr.sun_family = AF_UNIX;
2843 strncpy(sunaddr.sun_path, auth_sock_name,
2844 sizeof(sunaddr.sun_path));
2846 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2847 packet_disconnect("bind: %.100s", strerror(errno));
2849 /* Restore the privileged uid. */
2852 /* Start listening on the socket. */
2853 if (listen(sock, 5) < 0)
2854 packet_disconnect("listen: %.100s", strerror(errno));
2856 /* Allocate a channel for the authentication agent socket. */
2857 nc = channel_new("auth socket",
2858 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2859 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2860 0, xstrdup("auth socket"), 1);
2862 error("auth_input_request_forwarding: channel_new failed");
2863 auth_sock_cleanup_proc(pw);
2867 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2871 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2874 auth_input_open_request(int type, int plen, void *ctxt)
2877 int remote_id, sock;
2880 packet_integrity_check(plen, 4, type);
2882 /* Read the remote channel number from the message. */
2883 remote_id = packet_get_int();
2886 * Get a connection to the local authentication agent (this may again
2889 sock = ssh_get_authentication_socket();
2892 * If we could not connect the agent, send an error message back to
2893 * the server. This should never happen unless the agent dies,
2894 * because authentication forwarding is only enabled if we have an
2898 name = xstrdup("authentication agent connection");
2899 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2900 -1, 0, 0, 0, name, 1);
2902 error("auth_input_open_request: channel_new failed");
2906 c->remote_id = remote_id;
2910 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2911 packet_put_int(remote_id);
2913 /* Send a confirmation to the remote host. */
2914 debug("Forwarding authentication connection.");
2915 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2916 packet_put_int(remote_id);
2917 packet_put_int(c->self);