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 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 1.146 2001/12/06 18:20:32 stevesk Exp $");
62 * Pointer to an array containing all allocated channels. The array is
63 * dynamically extended as needed.
65 static Channel **channels = NULL;
68 * Size of the channel array. All slots of the array must always be
69 * initialized (at least the type field); unused slots set to NULL
71 static int channels_alloc = 0;
74 * Maximum file descriptor value used in any of the channels. This is
75 * updated in channel_new.
77 static int channel_max_fd = 0;
80 /* -- tcp forwarding */
83 * Data structure for storing which hosts are permitted for forward requests.
84 * The local sides of any remote forwards are stored in this array to prevent
85 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
86 * network (which might be behind a firewall).
89 char *host_to_connect; /* Connect to 'host'. */
90 u_short port_to_connect; /* Connect to 'port'. */
91 u_short listen_port; /* Remote side should listen port number. */
94 /* List of all permitted host/port pairs to connect. */
95 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
97 /* Number of permitted host/port pairs in the array. */
98 static int num_permitted_opens = 0;
100 * If this is true, all opens are permitted. This is the case on the server
101 * on which we have to trust the client anyway, and the user could do
102 * anything after logging in anyway.
104 static int all_opens_permitted = 0;
107 /* -- X11 forwarding */
109 /* Maximum number of fake X11 displays to try. */
110 #define MAX_DISPLAYS 1000
112 /* Saved X11 authentication protocol name. */
113 static char *x11_saved_proto = NULL;
115 /* Saved X11 authentication data. This is the real data. */
116 static char *x11_saved_data = NULL;
117 static u_int x11_saved_data_len = 0;
120 * Fake X11 authentication data. This is what the server will be sending us;
121 * we should replace any occurrences of this by the real data.
123 static char *x11_fake_data = NULL;
124 static u_int x11_fake_data_len;
127 /* -- agent forwarding */
131 /* Name and directory of socket for authentication agent forwarding. */
132 static char *auth_sock_name = NULL;
133 static char *auth_sock_dir = NULL;
135 /* AF_UNSPEC or AF_INET or AF_INET6 */
136 static int IPv4or6 = AF_UNSPEC;
139 static void port_open_helper(Channel *c, char *rtype);
141 /* -- channel core */
144 channel_lookup(int id)
148 if (id < 0 || id > channels_alloc) {
149 log("channel_lookup: %d: bad id", id);
154 log("channel_lookup: %d: bad id: channel free", id);
161 * Register filedescriptors for a channel, used when allocating a channel or
162 * when the channel consumer/producer is ready, e.g. shell exec'd
166 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
167 int extusage, int nonblock)
169 /* Update the maximum file descriptor value. */
170 channel_max_fd = MAX(channel_max_fd, rfd);
171 channel_max_fd = MAX(channel_max_fd, wfd);
172 channel_max_fd = MAX(channel_max_fd, efd);
174 /* XXX set close-on-exec -markus */
178 c->sock = (rfd == wfd) ? rfd : -1;
180 c->extended_usage = extusage;
182 /* XXX ugly hack: nonblock is only set by the server */
183 if (nonblock && isatty(c->rfd)) {
184 debug("channel %d: rfd %d isatty", c->self, c->rfd);
186 if (!isatty(c->wfd)) {
187 error("channel %d: wfd %d is not a tty?",
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 int window, int maxpack, int extusage, char *remote_name, int nonblock)
217 /* Do initial allocation if this is the first call. */
218 if (channels_alloc == 0) {
221 channels = xmalloc(channels_alloc * sizeof(Channel *));
222 for (i = 0; i < channels_alloc; i++)
224 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
226 /* Try to find a free slot where to put the new channel. */
227 for (found = -1, i = 0; i < channels_alloc; i++)
228 if (channels[i] == NULL) {
229 /* Found a free slot. */
234 /* There are no free slots. Take last+1 slot and expand the array. */
235 found = channels_alloc;
236 channels_alloc += 10;
237 debug2("channel: expanding %d", channels_alloc);
238 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
239 for (i = found; i < channels_alloc; i++)
242 /* Initialize and return new channel. */
243 c = channels[found] = xmalloc(sizeof(Channel));
244 memset(c, 0, sizeof(Channel));
245 buffer_init(&c->input);
246 buffer_init(&c->output);
247 buffer_init(&c->extended);
248 chan_init_iostates(c);
249 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
253 c->local_window = window;
254 c->local_window_max = window;
255 c->local_consumed = 0;
256 c->local_maxpacket = maxpack;
258 c->remote_name = remote_name;
259 c->remote_window = 0;
260 c->remote_maxpacket = 0;
265 c->detach_user = NULL;
266 c->input_filter = NULL;
267 debug("channel %d: new [%s]", found, remote_name);
272 channel_find_maxfd(void)
277 for (i = 0; i < channels_alloc; i++) {
280 max = MAX(max, c->rfd);
281 max = MAX(max, c->wfd);
282 max = MAX(max, c->efd);
289 channel_close_fd(int *fdp)
291 int ret = 0, fd = *fdp;
296 if (fd == channel_max_fd)
297 channel_max_fd = channel_find_maxfd();
302 /* Close all channel fd/socket. */
305 channel_close_fds(Channel *c)
307 debug3("channel_close_fds: channel %d: r %d w %d e %d",
308 c->self, c->rfd, c->wfd, c->efd);
310 channel_close_fd(&c->sock);
311 channel_close_fd(&c->rfd);
312 channel_close_fd(&c->wfd);
313 channel_close_fd(&c->efd);
316 /* Free the channel and close its fd/socket. */
319 channel_free(Channel *c)
324 for (n = 0, i = 0; i < channels_alloc; i++)
327 debug("channel_free: channel %d: %s, nchannels %d", c->self,
328 c->remote_name ? c->remote_name : "???", n);
330 s = channel_open_message();
331 debug3("channel_free: status: %s", s);
335 shutdown(c->sock, SHUT_RDWR);
336 channel_close_fds(c);
337 buffer_free(&c->input);
338 buffer_free(&c->output);
339 buffer_free(&c->extended);
340 if (c->remote_name) {
341 xfree(c->remote_name);
342 c->remote_name = NULL;
344 channels[c->self] = NULL;
349 channel_free_all(void)
353 for (i = 0; i < channels_alloc; i++)
354 if (channels[i] != NULL)
355 channel_free(channels[i]);
359 * Closes the sockets/fds of all channels. This is used to close extra file
360 * descriptors after a fork.
364 channel_close_all(void)
368 for (i = 0; i < channels_alloc; i++)
369 if (channels[i] != NULL)
370 channel_close_fds(channels[i]);
374 * Stop listening to channels.
378 channel_stop_listening(void)
383 for (i = 0; i < channels_alloc; i++) {
387 case SSH_CHANNEL_AUTH_SOCKET:
388 case SSH_CHANNEL_PORT_LISTENER:
389 case SSH_CHANNEL_RPORT_LISTENER:
390 case SSH_CHANNEL_X11_LISTENER:
391 channel_close_fd(&c->sock);
400 * Returns true if no channel has too much buffered data, and false if one or
401 * more channel is overfull.
405 channel_not_very_much_buffered_data(void)
410 for (i = 0; i < channels_alloc; i++) {
412 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
415 buffer_len(&c->input) > packet_get_maxsize()) {
416 debug("channel %d: big input buffer %d",
417 c->self, buffer_len(&c->input));
421 if (buffer_len(&c->output) > packet_get_maxsize()) {
422 debug("channel %d: big output buffer %d > %d",
423 c->self, buffer_len(&c->output),
424 packet_get_maxsize());
432 /* Returns true if any channel is still open. */
435 channel_still_open(void)
440 for (i = 0; i < channels_alloc; i++) {
445 case SSH_CHANNEL_X11_LISTENER:
446 case SSH_CHANNEL_PORT_LISTENER:
447 case SSH_CHANNEL_RPORT_LISTENER:
448 case SSH_CHANNEL_CLOSED:
449 case SSH_CHANNEL_AUTH_SOCKET:
450 case SSH_CHANNEL_DYNAMIC:
451 case SSH_CHANNEL_CONNECTING:
452 case SSH_CHANNEL_ZOMBIE:
454 case SSH_CHANNEL_LARVAL:
456 fatal("cannot happen: SSH_CHANNEL_LARVAL");
458 case SSH_CHANNEL_OPENING:
459 case SSH_CHANNEL_OPEN:
460 case SSH_CHANNEL_X11_OPEN:
462 case SSH_CHANNEL_INPUT_DRAINING:
463 case SSH_CHANNEL_OUTPUT_DRAINING:
465 fatal("cannot happen: OUT_DRAIN");
468 fatal("channel_still_open: bad channel type %d", c->type);
475 /* Returns the id of an open channel suitable for keepaliving */
478 channel_find_open(void)
483 for (i = 0; i < channels_alloc; i++) {
488 case SSH_CHANNEL_CLOSED:
489 case SSH_CHANNEL_DYNAMIC:
490 case SSH_CHANNEL_X11_LISTENER:
491 case SSH_CHANNEL_PORT_LISTENER:
492 case SSH_CHANNEL_RPORT_LISTENER:
493 case SSH_CHANNEL_OPENING:
494 case SSH_CHANNEL_CONNECTING:
495 case SSH_CHANNEL_ZOMBIE:
497 case SSH_CHANNEL_LARVAL:
498 case SSH_CHANNEL_AUTH_SOCKET:
499 case SSH_CHANNEL_OPEN:
500 case SSH_CHANNEL_X11_OPEN:
502 case SSH_CHANNEL_INPUT_DRAINING:
503 case SSH_CHANNEL_OUTPUT_DRAINING:
505 fatal("cannot happen: OUT_DRAIN");
508 fatal("channel_find_open: bad channel type %d", c->type);
517 * Returns a message describing the currently open forwarded connections,
518 * suitable for sending to the client. The message contains crlf pairs for
523 channel_open_message(void)
530 buffer_init(&buffer);
531 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
532 buffer_append(&buffer, buf, strlen(buf));
533 for (i = 0; i < channels_alloc; i++) {
538 case SSH_CHANNEL_X11_LISTENER:
539 case SSH_CHANNEL_PORT_LISTENER:
540 case SSH_CHANNEL_RPORT_LISTENER:
541 case SSH_CHANNEL_CLOSED:
542 case SSH_CHANNEL_AUTH_SOCKET:
543 case SSH_CHANNEL_ZOMBIE:
545 case SSH_CHANNEL_LARVAL:
546 case SSH_CHANNEL_OPENING:
547 case SSH_CHANNEL_CONNECTING:
548 case SSH_CHANNEL_DYNAMIC:
549 case SSH_CHANNEL_OPEN:
550 case SSH_CHANNEL_X11_OPEN:
551 case SSH_CHANNEL_INPUT_DRAINING:
552 case SSH_CHANNEL_OUTPUT_DRAINING:
553 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
554 c->self, c->remote_name,
555 c->type, c->remote_id,
556 c->istate, buffer_len(&c->input),
557 c->ostate, buffer_len(&c->output),
559 buffer_append(&buffer, buf, strlen(buf));
562 fatal("channel_open_message: bad channel type %d", c->type);
566 buffer_append(&buffer, "\0", 1);
567 cp = xstrdup(buffer_ptr(&buffer));
568 buffer_free(&buffer);
573 channel_send_open(int id)
575 Channel *c = channel_lookup(id);
577 log("channel_send_open: %d: bad id", id);
580 debug("send channel open %d", id);
581 packet_start(SSH2_MSG_CHANNEL_OPEN);
582 packet_put_cstring(c->ctype);
583 packet_put_int(c->self);
584 packet_put_int(c->local_window);
585 packet_put_int(c->local_maxpacket);
590 channel_request(int id, char *service, int wantconfirm)
592 channel_request_start(id, service, wantconfirm);
594 debug("channel request %d: %s", id, service) ;
597 channel_request_start(int id, char *service, int wantconfirm)
599 Channel *c = channel_lookup(id);
601 log("channel_request: %d: bad id", id);
604 packet_start(SSH2_MSG_CHANNEL_REQUEST);
605 packet_put_int(c->remote_id);
606 packet_put_cstring(service);
607 packet_put_char(wantconfirm);
610 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
612 Channel *c = channel_lookup(id);
614 log("channel_register_callback: %d: bad id", id);
622 channel_register_cleanup(int id, channel_callback_fn *fn)
624 Channel *c = channel_lookup(id);
626 log("channel_register_cleanup: %d: bad id", id);
632 channel_cancel_cleanup(int id)
634 Channel *c = channel_lookup(id);
636 log("channel_cancel_cleanup: %d: bad id", id);
639 c->detach_user = NULL;
642 channel_register_filter(int id, channel_filter_fn *fn)
644 Channel *c = channel_lookup(id);
646 log("channel_register_filter: %d: bad id", id);
649 c->input_filter = fn;
653 channel_set_fds(int id, int rfd, int wfd, int efd,
654 int extusage, int nonblock)
656 Channel *c = channel_lookup(id);
657 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
658 fatal("channel_activate for non-larval channel %d.", id);
659 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
660 c->type = SSH_CHANNEL_OPEN;
661 /* XXX window size? */
662 c->local_window = c->local_window_max = c->local_maxpacket * 2;
663 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
664 packet_put_int(c->remote_id);
665 packet_put_int(c->local_window);
670 * 'channel_pre*' are called just before select() to add any bits relevant to
671 * channels in the select bitmasks.
674 * 'channel_post*': perform any appropriate operations for channels which
675 * have events pending.
677 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
678 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
679 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
682 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
684 FD_SET(c->sock, readset);
688 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
690 debug3("channel %d: waiting for connection", c->self);
691 FD_SET(c->sock, writeset);
695 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
697 if (buffer_len(&c->input) < packet_get_maxsize())
698 FD_SET(c->sock, readset);
699 if (buffer_len(&c->output) > 0)
700 FD_SET(c->sock, writeset);
704 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
706 /* test whether sockets are 'alive' for read/write */
707 if (c->istate == CHAN_INPUT_OPEN)
708 if (buffer_len(&c->input) < packet_get_maxsize())
709 FD_SET(c->sock, 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->sock, writeset);
714 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
721 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
723 if (c->istate == CHAN_INPUT_OPEN &&
724 c->remote_window > 0 &&
725 buffer_len(&c->input) < c->remote_window)
726 FD_SET(c->rfd, readset);
727 if (c->ostate == CHAN_OUTPUT_OPEN ||
728 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
729 if (buffer_len(&c->output) > 0) {
730 FD_SET(c->wfd, writeset);
731 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
735 /** XXX check close conditions, too */
737 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
738 buffer_len(&c->extended) > 0)
739 FD_SET(c->efd, writeset);
740 else if (c->extended_usage == CHAN_EXTENDED_READ &&
741 buffer_len(&c->extended) < c->remote_window)
742 FD_SET(c->efd, readset);
747 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
749 if (buffer_len(&c->input) == 0) {
750 packet_start(SSH_MSG_CHANNEL_CLOSE);
751 packet_put_int(c->remote_id);
753 c->type = SSH_CHANNEL_CLOSED;
754 debug("channel %d: closing after input drain.", c->self);
759 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
761 if (buffer_len(&c->output) == 0)
764 FD_SET(c->sock, writeset);
768 * This is a special state for X11 authentication spoofing. An opened X11
769 * connection (when authentication spoofing is being done) remains in this
770 * state until the first packet has been completely read. The authentication
771 * data in that packet is then substituted by the real data if it matches the
772 * fake data, and the channel is put into normal mode.
773 * XXX All this happens at the client side.
774 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
777 x11_open_helper(Buffer *b)
780 u_int proto_len, data_len;
782 /* Check if the fixed size part of the packet is in buffer. */
783 if (buffer_len(b) < 12)
786 /* Parse the lengths of variable-length fields. */
787 ucp = (u_char *) buffer_ptr(b);
788 if (ucp[0] == 0x42) { /* Byte order MSB first. */
789 proto_len = 256 * ucp[6] + ucp[7];
790 data_len = 256 * ucp[8] + ucp[9];
791 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
792 proto_len = ucp[6] + 256 * ucp[7];
793 data_len = ucp[8] + 256 * ucp[9];
795 debug("Initial X11 packet contains bad byte order byte: 0x%x",
800 /* Check if the whole packet is in buffer. */
802 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
805 /* Check if authentication protocol matches. */
806 if (proto_len != strlen(x11_saved_proto) ||
807 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
808 debug("X11 connection uses different authentication protocol.");
811 /* Check if authentication data matches our fake data. */
812 if (data_len != x11_fake_data_len ||
813 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
814 x11_fake_data, x11_fake_data_len) != 0) {
815 debug("X11 auth data does not match fake data.");
818 /* Check fake data length */
819 if (x11_fake_data_len != x11_saved_data_len) {
820 error("X11 fake_data_len %d != saved_data_len %d",
821 x11_fake_data_len, x11_saved_data_len);
825 * Received authentication protocol and data match
826 * our fake data. Substitute the fake data with real
829 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
830 x11_saved_data, x11_saved_data_len);
835 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
837 int ret = x11_open_helper(&c->output);
839 /* Start normal processing for the channel. */
840 c->type = SSH_CHANNEL_OPEN;
841 channel_pre_open_13(c, readset, writeset);
842 } else if (ret == -1) {
844 * We have received an X11 connection that has bad
845 * authentication information.
847 log("X11 connection rejected because of wrong authentication.");
848 buffer_clear(&c->input);
849 buffer_clear(&c->output);
850 channel_close_fd(&c->sock);
852 c->type = SSH_CHANNEL_CLOSED;
853 packet_start(SSH_MSG_CHANNEL_CLOSE);
854 packet_put_int(c->remote_id);
860 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
862 int ret = x11_open_helper(&c->output);
864 /* c->force_drain = 1; */
867 c->type = SSH_CHANNEL_OPEN;
869 channel_pre_open_20(c, readset, writeset);
871 channel_pre_open_15(c, readset, writeset);
872 } else if (ret == -1) {
873 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
874 chan_read_failed(c); /** force close? */
875 chan_write_failed(c);
876 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
880 /* try to decode a socks4 header */
882 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
885 int len, have, i, found;
891 struct in_addr dest_addr;
894 debug2("channel %d: decode socks4", c->self);
896 have = buffer_len(&c->input);
897 len = sizeof(s4_req);
900 p = buffer_ptr(&c->input);
901 for (found = 0, i = len; i < have; i++) {
907 /* the peer is probably sending garbage */
908 debug("channel %d: decode socks4: too long",
915 buffer_get(&c->input, (char *)&s4_req.version, 1);
916 buffer_get(&c->input, (char *)&s4_req.command, 1);
917 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
918 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
919 have = buffer_len(&c->input);
920 p = buffer_ptr(&c->input);
922 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
924 fatal("channel %d: decode socks4: len %d > have %d",
926 strlcpy(username, p, sizeof(username));
927 buffer_consume(&c->input, len);
928 buffer_consume(&c->input, 1); /* trailing '\0' */
930 host = inet_ntoa(s4_req.dest_addr);
931 strlcpy(c->path, host, sizeof(c->path));
932 c->host_port = ntohs(s4_req.dest_port);
934 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
935 c->self, host, c->host_port, s4_req.command);
937 if (s4_req.command != 1) {
938 debug("channel %d: cannot handle: socks4 cn %d",
939 c->self, s4_req.command);
942 s4_rsp.version = 0; /* vn: 0 for reply */
943 s4_rsp.command = 90; /* cd: req granted */
944 s4_rsp.dest_port = 0; /* ignored */
945 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
946 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
950 /* dynamic port forwarding */
952 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
957 have = buffer_len(&c->input);
959 debug2("channel %d: pre_dynamic: have %d", c->self, have);
960 /* buffer_dump(&c->input); */
961 /* check if the fixed size part of the packet is in buffer. */
964 FD_SET(c->sock, readset);
967 /* try to guess the protocol */
968 p = buffer_ptr(&c->input);
971 ret = channel_decode_socks4(c, readset, writeset);
979 } else if (ret == 0) {
980 debug2("channel %d: pre_dynamic: need more", c->self);
982 FD_SET(c->sock, readset);
984 /* switch to the next state */
985 c->type = SSH_CHANNEL_OPENING;
986 port_open_helper(c, "direct-tcpip");
990 /* This is our fake X11 server socket. */
992 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
995 struct sockaddr addr;
998 char buf[16384], *remote_ipaddr;
1001 if (FD_ISSET(c->sock, readset)) {
1002 debug("X11 connection requested.");
1003 addrlen = sizeof(addr);
1004 newsock = accept(c->sock, &addr, &addrlen);
1006 error("accept: %.100s", strerror(errno));
1009 if (setsockopt(newsock, IPPROTO_TCP, TCP_NODELAY, &on,
1011 error("setsockopt TCP_NODELAY: %.100s",
1013 remote_ipaddr = get_peer_ipaddr(newsock);
1014 remote_port = get_peer_port(newsock);
1015 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1016 remote_ipaddr, remote_port);
1018 nc = channel_new("accepted x11 socket",
1019 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1020 c->local_window_max, c->local_maxpacket,
1021 0, xstrdup(buf), 1);
1024 xfree(remote_ipaddr);
1028 packet_start(SSH2_MSG_CHANNEL_OPEN);
1029 packet_put_cstring("x11");
1030 packet_put_int(nc->self);
1031 packet_put_int(c->local_window_max);
1032 packet_put_int(c->local_maxpacket);
1033 /* originator ipaddr and port */
1034 packet_put_cstring(remote_ipaddr);
1035 if (datafellows & SSH_BUG_X11FWD) {
1036 debug("ssh2 x11 bug compat mode");
1038 packet_put_int(remote_port);
1042 packet_start(SSH_SMSG_X11_OPEN);
1043 packet_put_int(nc->self);
1044 if (packet_get_protocol_flags() &
1045 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1046 packet_put_cstring(buf);
1049 xfree(remote_ipaddr);
1054 port_open_helper(Channel *c, char *rtype)
1058 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1059 u_short remote_port = get_peer_port(c->sock);
1061 direct = (strcmp(rtype, "direct-tcpip") == 0);
1063 snprintf(buf, sizeof buf,
1064 "%s: listening port %d for %.100s port %d, "
1065 "connect from %.200s port %d",
1066 rtype, c->listening_port, c->path, c->host_port,
1067 remote_ipaddr, remote_port);
1069 xfree(c->remote_name);
1070 c->remote_name = xstrdup(buf);
1073 packet_start(SSH2_MSG_CHANNEL_OPEN);
1074 packet_put_cstring(rtype);
1075 packet_put_int(c->self);
1076 packet_put_int(c->local_window_max);
1077 packet_put_int(c->local_maxpacket);
1079 /* target host, port */
1080 packet_put_cstring(c->path);
1081 packet_put_int(c->host_port);
1083 /* listen address, port */
1084 packet_put_cstring(c->path);
1085 packet_put_int(c->listening_port);
1087 /* originator host and port */
1088 packet_put_cstring(remote_ipaddr);
1089 packet_put_int(remote_port);
1092 packet_start(SSH_MSG_PORT_OPEN);
1093 packet_put_int(c->self);
1094 packet_put_cstring(c->path);
1095 packet_put_int(c->host_port);
1096 if (packet_get_protocol_flags() &
1097 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1098 packet_put_cstring(c->remote_name);
1101 xfree(remote_ipaddr);
1105 * This socket is listening for connections to a forwarded TCP/IP port.
1108 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1111 struct sockaddr addr;
1112 int newsock, nextstate;
1116 if (FD_ISSET(c->sock, readset)) {
1117 debug("Connection to port %d forwarding "
1118 "to %.100s port %d requested.",
1119 c->listening_port, c->path, c->host_port);
1121 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1122 nextstate = SSH_CHANNEL_OPENING;
1123 rtype = "forwarded-tcpip";
1125 if (c->host_port == 0) {
1126 nextstate = SSH_CHANNEL_DYNAMIC;
1127 rtype = "dynamic-tcpip";
1129 nextstate = SSH_CHANNEL_OPENING;
1130 rtype = "direct-tcpip";
1134 addrlen = sizeof(addr);
1135 newsock = accept(c->sock, &addr, &addrlen);
1137 error("accept: %.100s", strerror(errno));
1140 nc = channel_new(rtype,
1141 nextstate, newsock, newsock, -1,
1142 c->local_window_max, c->local_maxpacket,
1143 0, xstrdup(rtype), 1);
1145 error("channel_post_port_listener: no new channel:");
1149 nc->listening_port = c->listening_port;
1150 nc->host_port = c->host_port;
1151 strlcpy(nc->path, c->path, sizeof(nc->path));
1153 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1155 * do not call the channel_post handler until
1156 * this flag has been reset by a pre-handler.
1157 * otherwise the FD_ISSET calls might overflow
1161 port_open_helper(nc, rtype);
1167 * This is the authentication agent socket listening for connections from
1171 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1176 struct sockaddr addr;
1179 if (FD_ISSET(c->sock, readset)) {
1180 addrlen = sizeof(addr);
1181 newsock = accept(c->sock, &addr, &addrlen);
1183 error("accept from auth socket: %.100s", strerror(errno));
1186 name = xstrdup("accepted auth socket");
1187 nc = channel_new("accepted auth socket",
1188 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1189 c->local_window_max, c->local_maxpacket,
1192 error("channel_post_auth_listener: channel_new failed");
1197 packet_start(SSH2_MSG_CHANNEL_OPEN);
1198 packet_put_cstring("auth-agent@openssh.com");
1199 packet_put_int(nc->self);
1200 packet_put_int(c->local_window_max);
1201 packet_put_int(c->local_maxpacket);
1203 packet_start(SSH_SMSG_AGENT_OPEN);
1204 packet_put_int(nc->self);
1211 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1214 socklen_t sz = sizeof(err);
1216 if (FD_ISSET(c->sock, writeset)) {
1217 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1220 error("getsockopt SO_ERROR failed");
1223 debug("channel %d: connected", c->self);
1224 c->type = SSH_CHANNEL_OPEN;
1226 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1227 packet_put_int(c->remote_id);
1228 packet_put_int(c->self);
1229 packet_put_int(c->local_window);
1230 packet_put_int(c->local_maxpacket);
1232 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1233 packet_put_int(c->remote_id);
1234 packet_put_int(c->self);
1237 debug("channel %d: not connected: %s",
1238 c->self, strerror(err));
1240 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1241 packet_put_int(c->remote_id);
1242 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1243 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1244 packet_put_cstring(strerror(err));
1245 packet_put_cstring("");
1248 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1249 packet_put_int(c->remote_id);
1258 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1264 FD_ISSET(c->rfd, readset)) {
1265 len = read(c->rfd, buf, sizeof(buf));
1266 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1269 debug("channel %d: read<=0 rfd %d len %d",
1270 c->self, c->rfd, len);
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 c->type = SSH_CHANNEL_INPUT_DRAINING;
1278 debug("channel %d: input draining.", c->self);
1280 chan_read_failed(c);
1284 if (c->input_filter != NULL) {
1285 if (c->input_filter(c, buf, len) == -1) {
1286 debug("channel %d: filter stops", c->self);
1287 chan_read_failed(c);
1290 buffer_append(&c->input, buf, len);
1296 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1303 /* Send buffered output data to the socket. */
1305 FD_ISSET(c->wfd, writeset) &&
1306 buffer_len(&c->output) > 0) {
1307 data = buffer_ptr(&c->output);
1308 dlen = buffer_len(&c->output);
1309 len = write(c->wfd, data, dlen);
1310 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1313 if (c->type != SSH_CHANNEL_OPEN) {
1314 debug("channel %d: not open", c->self);
1317 } else if (compat13) {
1318 buffer_consume(&c->output, buffer_len(&c->output));
1319 debug("channel %d: input draining.", c->self);
1320 c->type = SSH_CHANNEL_INPUT_DRAINING;
1322 chan_write_failed(c);
1326 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1327 if (tcgetattr(c->wfd, &tio) == 0 &&
1328 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1330 * Simulate echo to reduce the impact of
1331 * traffic analysis. We need to match the
1332 * size of a SSH2_MSG_CHANNEL_DATA message
1333 * (4 byte channel id + data)
1335 packet_send_ignore(4 + len);
1339 buffer_consume(&c->output, len);
1340 if (compat20 && len > 0) {
1341 c->local_consumed += len;
1347 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1352 /** XXX handle drain efd, too */
1354 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1355 FD_ISSET(c->efd, writeset) &&
1356 buffer_len(&c->extended) > 0) {
1357 len = write(c->efd, buffer_ptr(&c->extended),
1358 buffer_len(&c->extended));
1359 debug2("channel %d: written %d to efd %d",
1360 c->self, len, c->efd);
1361 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1364 debug2("channel %d: closing write-efd %d",
1366 channel_close_fd(&c->efd);
1368 buffer_consume(&c->extended, len);
1369 c->local_consumed += len;
1371 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1372 FD_ISSET(c->efd, readset)) {
1373 len = read(c->efd, buf, sizeof(buf));
1374 debug2("channel %d: read %d from efd %d",
1375 c->self, len, c->efd);
1376 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1379 debug2("channel %d: closing read-efd %d",
1381 channel_close_fd(&c->efd);
1383 buffer_append(&c->extended, buf, len);
1390 channel_check_window(Channel *c)
1392 if (c->type == SSH_CHANNEL_OPEN &&
1393 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1394 c->local_window < c->local_window_max/2 &&
1395 c->local_consumed > 0) {
1396 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1397 packet_put_int(c->remote_id);
1398 packet_put_int(c->local_consumed);
1400 debug2("channel %d: window %d sent adjust %d",
1401 c->self, c->local_window,
1403 c->local_window += c->local_consumed;
1404 c->local_consumed = 0;
1410 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1414 channel_handle_rfd(c, readset, writeset);
1415 channel_handle_wfd(c, readset, writeset);
1419 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1423 channel_handle_rfd(c, readset, writeset);
1424 channel_handle_wfd(c, readset, writeset);
1425 channel_handle_efd(c, readset, writeset);
1427 channel_check_window(c);
1431 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1434 /* Send buffered output data to the socket. */
1435 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1436 len = write(c->sock, buffer_ptr(&c->output),
1437 buffer_len(&c->output));
1439 buffer_consume(&c->output, buffer_len(&c->output));
1441 buffer_consume(&c->output, len);
1446 channel_handler_init_20(void)
1448 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1449 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1450 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1451 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1452 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1453 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1454 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1455 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1457 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1458 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1459 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1460 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1461 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1462 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1463 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1467 channel_handler_init_13(void)
1469 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1470 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1471 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1472 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1473 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1474 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1475 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1476 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1477 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1479 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1480 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1481 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1482 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1483 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1484 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1485 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1489 channel_handler_init_15(void)
1491 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1492 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1493 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1494 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1495 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1496 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1497 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1499 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1500 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1501 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1502 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1503 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1504 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1508 channel_handler_init(void)
1511 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1512 channel_pre[i] = NULL;
1513 channel_post[i] = NULL;
1516 channel_handler_init_20();
1518 channel_handler_init_13();
1520 channel_handler_init_15();
1523 /* gc dead channels */
1525 channel_garbage_collect(Channel *c)
1529 if (c->detach_user != NULL) {
1530 if (!chan_is_dead(c, 0))
1532 debug("channel %d: gc: notify user", c->self);
1533 c->detach_user(c->self, NULL);
1534 /* if we still have a callback */
1535 if (c->detach_user != NULL)
1537 debug("channel %d: gc: user detached", c->self);
1539 if (!chan_is_dead(c, 1))
1541 debug("channel %d: garbage collecting", c->self);
1546 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1548 static int did_init = 0;
1553 channel_handler_init();
1556 for (i = 0; i < channels_alloc; i++) {
1560 if (ftab[c->type] != NULL)
1561 (*ftab[c->type])(c, readset, writeset);
1562 channel_garbage_collect(c);
1567 * Allocate/update select bitmasks and add any bits relevant to channels in
1571 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1572 int *nallocp, int rekeying)
1577 n = MAX(*maxfdp, channel_max_fd);
1579 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1580 /* perhaps check sz < nalloc/2 and shrink? */
1581 if (*readsetp == NULL || sz > *nallocp) {
1582 *readsetp = xrealloc(*readsetp, sz);
1583 *writesetp = xrealloc(*writesetp, sz);
1587 memset(*readsetp, 0, sz);
1588 memset(*writesetp, 0, sz);
1591 channel_handler(channel_pre, *readsetp, *writesetp);
1595 * After select, perform any appropriate operations for channels which have
1599 channel_after_select(fd_set * readset, fd_set * writeset)
1601 channel_handler(channel_post, readset, writeset);
1605 /* If there is data to send to the connection, enqueue some of it now. */
1608 channel_output_poll(void)
1613 for (i = 0; i < channels_alloc; i++) {
1619 * We are only interested in channels that can have buffered
1623 if (c->type != SSH_CHANNEL_OPEN &&
1624 c->type != SSH_CHANNEL_INPUT_DRAINING)
1627 if (c->type != SSH_CHANNEL_OPEN)
1631 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1632 /* XXX is this true? */
1633 debug3("channel %d: will not send data after close", c->self);
1637 /* Get the amount of buffered data for this channel. */
1638 if ((c->istate == CHAN_INPUT_OPEN ||
1639 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1640 (len = buffer_len(&c->input)) > 0) {
1642 * Send some data for the other side over the secure
1646 if (len > c->remote_window)
1647 len = c->remote_window;
1648 if (len > c->remote_maxpacket)
1649 len = c->remote_maxpacket;
1651 if (packet_is_interactive()) {
1655 /* Keep the packets at reasonable size. */
1656 if (len > packet_get_maxsize()/2)
1657 len = packet_get_maxsize()/2;
1661 packet_start(compat20 ?
1662 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1663 packet_put_int(c->remote_id);
1664 packet_put_string(buffer_ptr(&c->input), len);
1666 buffer_consume(&c->input, len);
1667 c->remote_window -= len;
1669 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1671 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1673 * input-buffer is empty and read-socket shutdown:
1674 * tell peer, that we will not send more data: send IEOF
1678 /* Send extended data, i.e. stderr */
1680 c->remote_window > 0 &&
1681 (len = buffer_len(&c->extended)) > 0 &&
1682 c->extended_usage == CHAN_EXTENDED_READ) {
1683 debug2("channel %d: rwin %d elen %d euse %d",
1684 c->self, c->remote_window, buffer_len(&c->extended),
1686 if (len > c->remote_window)
1687 len = c->remote_window;
1688 if (len > c->remote_maxpacket)
1689 len = c->remote_maxpacket;
1690 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1691 packet_put_int(c->remote_id);
1692 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1693 packet_put_string(buffer_ptr(&c->extended), len);
1695 buffer_consume(&c->extended, len);
1696 c->remote_window -= len;
1697 debug2("channel %d: sent ext data %d", c->self, len);
1703 /* -- protocol input */
1706 channel_input_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);
1717 packet_disconnect("Received data for nonexistent channel %d.", id);
1719 /* Ignore any data for non-open channels (might happen on close) */
1720 if (c->type != SSH_CHANNEL_OPEN &&
1721 c->type != SSH_CHANNEL_X11_OPEN)
1724 /* same for protocol 1.5 if output end is no longer open */
1725 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1729 data = packet_get_string(&data_len);
1733 if (data_len > c->local_maxpacket) {
1734 log("channel %d: rcvd big packet %d, maxpack %d",
1735 c->self, data_len, c->local_maxpacket);
1737 if (data_len > c->local_window) {
1738 log("channel %d: rcvd too much data %d, win %d",
1739 c->self, data_len, c->local_window);
1743 c->local_window -= data_len;
1745 packet_integrity_check(plen, 4 + 4 + data_len, type);
1747 buffer_append(&c->output, data, data_len);
1752 channel_input_extended_data(int type, int plen, void *ctxt)
1760 /* Get the channel number and verify it. */
1761 id = packet_get_int();
1762 c = channel_lookup(id);
1765 packet_disconnect("Received extended_data for bad channel %d.", id);
1766 if (c->type != SSH_CHANNEL_OPEN) {
1767 log("channel %d: ext data for non open", id);
1770 tcode = packet_get_int();
1772 c->extended_usage != CHAN_EXTENDED_WRITE ||
1773 tcode != SSH2_EXTENDED_DATA_STDERR) {
1774 log("channel %d: bad ext data", c->self);
1777 data = packet_get_string(&data_len);
1779 if (data_len > c->local_window) {
1780 log("channel %d: rcvd too much extended_data %d, win %d",
1781 c->self, data_len, c->local_window);
1785 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1786 c->local_window -= data_len;
1787 buffer_append(&c->extended, data, data_len);
1792 channel_input_ieof(int type, int plen, void *ctxt)
1797 packet_integrity_check(plen, 4, type);
1799 id = packet_get_int();
1800 c = channel_lookup(id);
1802 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1805 /* XXX force input close */
1806 if (c->force_drain) {
1807 debug("channel %d: FORCE input drain", c->self);
1808 c->istate = CHAN_INPUT_WAIT_DRAIN;
1814 channel_input_close(int type, int plen, void *ctxt)
1819 packet_integrity_check(plen, 4, type);
1821 id = packet_get_int();
1822 c = channel_lookup(id);
1824 packet_disconnect("Received close for nonexistent channel %d.", id);
1827 * Send a confirmation that we have closed the channel and no more
1828 * data is coming for it.
1830 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1831 packet_put_int(c->remote_id);
1835 * If the channel is in closed state, we have sent a close request,
1836 * and the other side will eventually respond with a confirmation.
1837 * Thus, we cannot free the channel here, because then there would be
1838 * no-one to receive the confirmation. The channel gets freed when
1839 * the confirmation arrives.
1841 if (c->type != SSH_CHANNEL_CLOSED) {
1843 * Not a closed channel - mark it as draining, which will
1844 * cause it to be freed later.
1846 buffer_consume(&c->input, buffer_len(&c->input));
1847 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1851 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1853 channel_input_oclose(int type, int plen, void *ctxt)
1855 int id = packet_get_int();
1856 Channel *c = channel_lookup(id);
1857 packet_integrity_check(plen, 4, type);
1859 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1860 chan_rcvd_oclose(c);
1864 channel_input_close_confirmation(int type, int plen, void *ctxt)
1866 int id = packet_get_int();
1867 Channel *c = channel_lookup(id);
1871 packet_disconnect("Received close confirmation for "
1872 "out-of-range channel %d.", id);
1873 if (c->type != SSH_CHANNEL_CLOSED)
1874 packet_disconnect("Received close confirmation for "
1875 "non-closed channel %d (type %d).", id, c->type);
1880 channel_input_open_confirmation(int type, int plen, void *ctxt)
1886 packet_integrity_check(plen, 4 + 4, type);
1888 id = packet_get_int();
1889 c = channel_lookup(id);
1891 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1892 packet_disconnect("Received open confirmation for "
1893 "non-opening channel %d.", id);
1894 remote_id = packet_get_int();
1895 /* Record the remote channel number and mark that the channel is now open. */
1896 c->remote_id = remote_id;
1897 c->type = SSH_CHANNEL_OPEN;
1900 c->remote_window = packet_get_int();
1901 c->remote_maxpacket = packet_get_int();
1903 if (c->cb_fn != NULL && c->cb_event == type) {
1904 debug2("callback start");
1905 c->cb_fn(c->self, c->cb_arg);
1906 debug2("callback done");
1908 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1909 c->remote_window, c->remote_maxpacket);
1914 reason2txt(int reason)
1917 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1918 return "administratively prohibited";
1919 case SSH2_OPEN_CONNECT_FAILED:
1920 return "connect failed";
1921 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1922 return "unknown channel type";
1923 case SSH2_OPEN_RESOURCE_SHORTAGE:
1924 return "resource shortage";
1926 return "unknown reason";
1930 channel_input_open_failure(int type, int plen, void *ctxt)
1933 char *msg = NULL, *lang = NULL;
1937 packet_integrity_check(plen, 4, type);
1939 id = packet_get_int();
1940 c = channel_lookup(id);
1942 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1943 packet_disconnect("Received open failure for "
1944 "non-opening channel %d.", id);
1946 reason = packet_get_int();
1947 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1948 msg = packet_get_string(NULL);
1949 lang = packet_get_string(NULL);
1952 log("channel %d: open failed: %s%s%s", id,
1953 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1959 /* Free the channel. This will also close the socket. */
1964 channel_input_channel_request(int type, int plen, void *ctxt)
1969 id = packet_get_int();
1970 c = channel_lookup(id);
1973 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1974 packet_disconnect("Received request for "
1975 "non-open channel %d.", id);
1976 if (c->cb_fn != NULL && c->cb_event == type) {
1977 debug2("callback start");
1978 c->cb_fn(c->self, c->cb_arg);
1979 debug2("callback done");
1981 char *service = packet_get_string(NULL);
1982 debug("channel %d: rcvd request for %s", c->self, service);
1983 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1989 channel_input_window_adjust(int type, int plen, void *ctxt)
1997 /* Get the channel number and verify it. */
1998 id = packet_get_int();
1999 c = channel_lookup(id);
2001 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2002 log("Received window adjust for "
2003 "non-open channel %d.", id);
2006 adjust = packet_get_int();
2008 debug2("channel %d: rcvd adjust %d", id, adjust);
2009 c->remote_window += adjust;
2013 channel_input_port_open(int type, int plen, void *ctxt)
2017 char *host, *originator_string;
2018 int remote_id, sock = -1;
2020 remote_id = packet_get_int();
2021 host = packet_get_string(NULL);
2022 host_port = packet_get_int();
2024 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2025 originator_string = packet_get_string(NULL);
2027 originator_string = xstrdup("unknown (remote did not supply name)");
2030 sock = channel_connect_to(host, host_port);
2032 c = channel_new("connected socket",
2033 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2034 originator_string, 1);
2036 error("channel_input_port_open: channel_new failed");
2039 c->remote_id = remote_id;
2043 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2044 packet_put_int(remote_id);
2051 /* -- tcp forwarding */
2054 channel_set_af(int af)
2060 * Initiate forwarding of connections to local port "port" through the secure
2061 * channel to host:port from remote side.
2064 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2065 u_short port_to_connect, int gateway_ports)
2067 return channel_request_forwarding(
2069 host_to_connect, port_to_connect,
2070 gateway_ports, /*remote_fwd*/ 0);
2074 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2075 * (SSH_CHANNEL_RPORT_LISTENER).
2078 channel_request_forwarding(
2079 const char *listen_address, u_short listen_port,
2080 const char *host_to_connect, u_short port_to_connect,
2081 int gateway_ports, int remote_fwd)
2084 int success, sock, on = 1, type;
2085 struct addrinfo hints, *ai, *aitop;
2086 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2088 struct linger linger;
2093 host = listen_address;
2094 type = SSH_CHANNEL_RPORT_LISTENER;
2096 host = host_to_connect;
2097 type = SSH_CHANNEL_PORT_LISTENER;
2100 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2101 error("Forward host name too long.");
2105 /* XXX listen_address is currently ignored */
2107 * getaddrinfo returns a loopback address if the hostname is
2108 * set to NULL and hints.ai_flags is not AI_PASSIVE
2110 memset(&hints, 0, sizeof(hints));
2111 hints.ai_family = IPv4or6;
2112 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2113 hints.ai_socktype = SOCK_STREAM;
2114 snprintf(strport, sizeof strport, "%d", listen_port);
2115 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2116 packet_disconnect("getaddrinfo: fatal error");
2118 for (ai = aitop; ai; ai = ai->ai_next) {
2119 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2121 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2122 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2123 error("channel_request_forwarding: getnameinfo failed");
2126 /* Create a port to listen for the host. */
2127 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2129 /* this is no error since kernel may not support ipv6 */
2130 verbose("socket: %.100s", strerror(errno));
2134 * Set socket options. We would like the socket to disappear
2135 * as soon as it has been closed for whatever reason.
2137 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2139 linger.l_linger = 5;
2140 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2141 debug("Local forwarding listening on %s port %s.", ntop, strport);
2143 /* Bind the socket to the address. */
2144 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2145 /* address can be in use ipv6 address is already bound */
2147 error("bind: %.100s", strerror(errno));
2149 verbose("bind: %.100s", strerror(errno));
2154 /* Start listening for connections on the socket. */
2155 if (listen(sock, 5) < 0) {
2156 error("listen: %.100s", strerror(errno));
2160 /* Allocate a channel number for the socket. */
2161 c = channel_new("port listener", type, sock, sock, -1,
2162 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2163 0, xstrdup("port listener"), 1);
2165 error("channel_request_forwarding: channel_new failed");
2169 strlcpy(c->path, host, sizeof(c->path));
2170 c->host_port = port_to_connect;
2171 c->listening_port = listen_port;
2175 error("channel_request_forwarding: cannot listen to port: %d",
2177 freeaddrinfo(aitop);
2182 * Initiate forwarding of connections to port "port" on remote host through
2183 * the secure channel to host:port from local side.
2187 channel_request_remote_forwarding(u_short listen_port,
2188 const char *host_to_connect, u_short port_to_connect)
2190 int payload_len, type, success = 0;
2192 /* Record locally that connection to this host/port is permitted. */
2193 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2194 fatal("channel_request_remote_forwarding: too many forwards");
2196 /* Send the forward request to the remote side. */
2198 const char *address_to_bind = "0.0.0.0";
2199 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2200 packet_put_cstring("tcpip-forward");
2201 packet_put_char(0); /* boolean: want reply */
2202 packet_put_cstring(address_to_bind);
2203 packet_put_int(listen_port);
2205 packet_write_wait();
2206 /* Assume that server accepts the request */
2209 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2210 packet_put_int(listen_port);
2211 packet_put_cstring(host_to_connect);
2212 packet_put_int(port_to_connect);
2214 packet_write_wait();
2216 /* Wait for response from the remote side. */
2217 type = packet_read(&payload_len);
2219 case SSH_SMSG_SUCCESS:
2222 case SSH_SMSG_FAILURE:
2223 log("Warning: Server denied remote port forwarding.");
2226 /* Unknown packet */
2227 packet_disconnect("Protocol error for port forward request:"
2228 "received packet type %d.", type);
2232 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2233 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2234 permitted_opens[num_permitted_opens].listen_port = listen_port;
2235 num_permitted_opens++;
2240 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2241 * listening for the port, and sends back a success reply (or disconnect
2242 * message if there was an error). This never returns if there was an error.
2246 channel_input_port_forward_request(int is_root, int gateway_ports)
2248 u_short port, host_port;
2251 /* Get arguments from the packet. */
2252 port = packet_get_int();
2253 hostname = packet_get_string(NULL);
2254 host_port = packet_get_int();
2258 * Check that an unprivileged user is not trying to forward a
2261 if (port < IPPORT_RESERVED && !is_root)
2262 packet_disconnect("Requested forwarding of port %d but user is not root.",
2265 /* Initiate forwarding */
2266 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2268 /* Free the argument string. */
2273 * Permits opening to any host/port if permitted_opens[] is empty. This is
2274 * usually called by the server, because the user could connect to any port
2275 * anyway, and the server has no way to know but to trust the client anyway.
2278 channel_permit_all_opens(void)
2280 if (num_permitted_opens == 0)
2281 all_opens_permitted = 1;
2285 channel_add_permitted_opens(char *host, int port)
2287 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2288 fatal("channel_request_remote_forwarding: too many forwards");
2289 debug("allow port forwarding to host %s port %d", host, port);
2291 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2292 permitted_opens[num_permitted_opens].port_to_connect = port;
2293 num_permitted_opens++;
2295 all_opens_permitted = 0;
2299 channel_clear_permitted_opens(void)
2303 for (i = 0; i < num_permitted_opens; i++)
2304 xfree(permitted_opens[i].host_to_connect);
2305 num_permitted_opens = 0;
2310 /* return socket to remote host, port */
2312 connect_to(const char *host, u_short port)
2314 struct addrinfo hints, *ai, *aitop;
2315 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2319 memset(&hints, 0, sizeof(hints));
2320 hints.ai_family = IPv4or6;
2321 hints.ai_socktype = SOCK_STREAM;
2322 snprintf(strport, sizeof strport, "%d", port);
2323 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2324 error("connect_to %.100s: unknown host (%s)", host,
2325 gai_strerror(gaierr));
2328 for (ai = aitop; ai; ai = ai->ai_next) {
2329 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2331 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2332 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2333 error("connect_to: getnameinfo failed");
2336 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2338 error("socket: %.100s", strerror(errno));
2341 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2342 fatal("connect_to: F_SETFL: %s", strerror(errno));
2343 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2344 errno != EINPROGRESS) {
2345 error("connect_to %.100s port %s: %.100s", ntop, strport,
2348 continue; /* fail -- try next */
2350 break; /* success */
2353 freeaddrinfo(aitop);
2355 error("connect_to %.100s port %d: failed.", host, port);
2363 channel_connect_by_listen_address(u_short listen_port)
2367 for (i = 0; i < num_permitted_opens; i++)
2368 if (permitted_opens[i].listen_port == listen_port)
2370 permitted_opens[i].host_to_connect,
2371 permitted_opens[i].port_to_connect);
2372 error("WARNING: Server requests forwarding for unknown listen_port %d",
2377 /* Check if connecting to that port is permitted and connect. */
2379 channel_connect_to(const char *host, u_short port)
2383 permit = all_opens_permitted;
2385 for (i = 0; i < num_permitted_opens; i++)
2386 if (permitted_opens[i].port_to_connect == port &&
2387 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2392 log("Received request to connect to host %.100s port %d, "
2393 "but the request was denied.", host, port);
2396 return connect_to(host, port);
2399 /* -- X11 forwarding */
2402 * Creates an internet domain socket for listening for X11 connections.
2403 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2407 x11_create_display_inet(int screen_number, int x11_display_offset)
2409 int display_number, sock;
2411 struct addrinfo hints, *ai, *aitop;
2412 char strport[NI_MAXSERV];
2413 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2415 char hostname[MAXHOSTNAMELEN];
2417 for (display_number = x11_display_offset;
2418 display_number < MAX_DISPLAYS;
2420 port = 6000 + display_number;
2421 memset(&hints, 0, sizeof(hints));
2422 hints.ai_family = IPv4or6;
2423 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2424 hints.ai_socktype = SOCK_STREAM;
2425 snprintf(strport, sizeof strport, "%d", port);
2426 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2427 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2430 for (ai = aitop; ai; ai = ai->ai_next) {
2431 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2433 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2435 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2436 error("socket: %.100s", strerror(errno));
2439 debug("x11_create_display_inet: Socket family %d not supported",
2444 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2445 debug("bind port %d: %.100s", port, strerror(errno));
2451 for (n = 0; n < num_socks; n++) {
2457 socks[num_socks++] = sock;
2458 #ifndef DONT_TRY_OTHER_AF
2459 if (num_socks == NUM_SOCKS)
2465 freeaddrinfo(aitop);
2469 if (display_number >= MAX_DISPLAYS) {
2470 error("Failed to allocate internet-domain X11 display socket.");
2473 /* Start listening for connections on the socket. */
2474 for (n = 0; n < num_socks; n++) {
2476 if (listen(sock, 5) < 0) {
2477 error("listen: %.100s", strerror(errno));
2483 /* Set up a suitable value for the DISPLAY variable. */
2484 if (gethostname(hostname, sizeof(hostname)) < 0)
2485 fatal("gethostname: %.100s", strerror(errno));
2487 #ifdef IPADDR_IN_DISPLAY
2489 * HPUX detects the local hostname in the DISPLAY variable and tries
2490 * to set up a shared memory connection to the server, which it
2491 * incorrectly supposes to be local.
2493 * The workaround - as used in later $$H and other programs - is
2494 * is to set display to the host's IP address.
2498 struct in_addr my_addr;
2500 he = gethostbyname(hostname);
2502 error("[X11-broken-fwd-hostname-workaround] Could not get "
2503 "IP address for hostname %s.", hostname);
2505 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2506 "Could not get IP address for hostname %s.", hostname);
2508 shutdown(sock, SHUT_RDWR);
2514 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2516 /* Set DISPLAY to <ip address>:screen.display */
2517 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2518 display_number, screen_number);
2520 #else /* IPADDR_IN_DISPLAY */
2521 /* Just set DISPLAY to hostname:screen.display */
2522 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2523 display_number, screen_number);
2524 #endif /* IPADDR_IN_DISPLAY */
2526 /* Allocate a channel for each socket. */
2527 for (n = 0; n < num_socks; n++) {
2529 (void) channel_new("x11 listener",
2530 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2531 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2532 0, xstrdup("X11 inet listener"), 1);
2535 /* Return a suitable value for the DISPLAY environment variable. */
2536 return xstrdup(display);
2540 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2544 connect_local_xsocket(u_int dnr)
2546 static const char *const x_sockets[] = {
2548 "/var/X/.X11-unix/X" "%u",
2549 "/usr/spool/sockets/X11/" "%u",
2553 struct sockaddr_un addr;
2554 const char *const * path;
2556 for (path = x_sockets; *path; ++path) {
2557 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2559 error("socket: %.100s", strerror(errno));
2560 memset(&addr, 0, sizeof(addr));
2561 addr.sun_family = AF_UNIX;
2562 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2563 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2567 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2572 x11_connect_display(void)
2574 int display_number, sock = 0, on = 1;
2575 const char *display;
2576 char buf[1024], *cp;
2577 struct addrinfo hints, *ai, *aitop;
2578 char strport[NI_MAXSERV];
2581 /* Try to open a socket for the local X server. */
2582 display = getenv("DISPLAY");
2584 error("DISPLAY not set.");
2588 * Now we decode the value of the DISPLAY variable and make a
2589 * connection to the real X server.
2593 * Check if it is a unix domain socket. Unix domain displays are in
2594 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2596 if (strncmp(display, "unix:", 5) == 0 ||
2597 display[0] == ':') {
2598 /* Connect to the unix domain socket. */
2599 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2600 error("Could not parse display number from DISPLAY: %.100s",
2604 /* Create a socket. */
2605 sock = connect_local_xsocket(display_number);
2609 /* OK, we now have a connection to the display. */
2613 * Connect to an inet socket. The DISPLAY value is supposedly
2614 * hostname:d[.s], where hostname may also be numeric IP address.
2616 strlcpy(buf, display, sizeof(buf));
2617 cp = strchr(buf, ':');
2619 error("Could not find ':' in DISPLAY: %.100s", display);
2623 /* buf now contains the host name. But first we parse the display number. */
2624 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2625 error("Could not parse display number from DISPLAY: %.100s",
2630 /* Look up the host address */
2631 memset(&hints, 0, sizeof(hints));
2632 hints.ai_family = IPv4or6;
2633 hints.ai_socktype = SOCK_STREAM;
2634 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2635 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2636 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2639 for (ai = aitop; ai; ai = ai->ai_next) {
2640 /* Create a socket. */
2641 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2643 debug("socket: %.100s", strerror(errno));
2646 /* Connect it to the display. */
2647 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2648 debug("connect %.100s port %d: %.100s", buf,
2649 6000 + display_number, strerror(errno));
2656 freeaddrinfo(aitop);
2658 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2662 if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on) == -1)
2663 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
2668 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2669 * the remote channel number. We should do whatever we want, and respond
2670 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2674 x11_input_open(int type, int plen, void *ctxt)
2677 int remote_id, sock = 0;
2680 debug("Received X11 open request.");
2682 remote_id = packet_get_int();
2684 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2685 remote_host = packet_get_string(NULL);
2687 remote_host = xstrdup("unknown (remote did not supply name)");
2691 /* Obtain a connection to the real X display. */
2692 sock = x11_connect_display();
2694 /* Allocate a channel for this connection. */
2695 c = channel_new("connected x11 socket",
2696 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2699 error("x11_input_open: channel_new failed");
2702 c->remote_id = remote_id;
2707 /* Send refusal to the remote host. */
2708 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2709 packet_put_int(remote_id);
2711 /* Send a confirmation to the remote host. */
2712 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2713 packet_put_int(remote_id);
2714 packet_put_int(c->self);
2719 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2721 deny_input_open(int type, int plen, void *ctxt)
2723 int rchan = packet_get_int();
2725 case SSH_SMSG_AGENT_OPEN:
2726 error("Warning: ssh server tried agent forwarding.");
2728 case SSH_SMSG_X11_OPEN:
2729 error("Warning: ssh server tried X11 forwarding.");
2732 error("deny_input_open: type %d plen %d", type, plen);
2735 error("Warning: this is probably a break in attempt by a malicious server.");
2736 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2737 packet_put_int(rchan);
2742 * Requests forwarding of X11 connections, generates fake authentication
2743 * data, and enables authentication spoofing.
2744 * This should be called in the client only.
2747 x11_request_forwarding_with_spoofing(int client_session_id,
2748 const char *proto, const char *data)
2750 u_int data_len = (u_int) strlen(data) / 2;
2751 u_int i, value, len;
2757 cp = getenv("DISPLAY");
2759 cp = strchr(cp, ':');
2761 cp = strchr(cp, '.');
2763 screen_number = atoi(cp + 1);
2767 /* Save protocol name. */
2768 x11_saved_proto = xstrdup(proto);
2771 * Extract real authentication data and generate fake data of the
2774 x11_saved_data = xmalloc(data_len);
2775 x11_fake_data = xmalloc(data_len);
2776 for (i = 0; i < data_len; i++) {
2777 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2778 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2780 rand = arc4random();
2781 x11_saved_data[i] = value;
2782 x11_fake_data[i] = rand & 0xff;
2785 x11_saved_data_len = data_len;
2786 x11_fake_data_len = data_len;
2788 /* Convert the fake data into hex. */
2789 len = 2 * data_len + 1;
2790 new_data = xmalloc(len);
2791 for (i = 0; i < data_len; i++)
2792 snprintf(new_data + 2 * i, len - 2 * i,
2793 "%02x", (u_char) x11_fake_data[i]);
2795 /* Send the request packet. */
2797 channel_request_start(client_session_id, "x11-req", 0);
2798 packet_put_char(0); /* XXX bool single connection */
2800 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2802 packet_put_cstring(proto);
2803 packet_put_cstring(new_data);
2804 packet_put_int(screen_number);
2806 packet_write_wait();
2811 /* -- agent forwarding */
2813 /* Sends a message to the server to request authentication fd forwarding. */
2816 auth_request_forwarding(void)
2818 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2820 packet_write_wait();
2824 * Returns the name of the forwarded authentication socket. Returns NULL if
2825 * there is no forwarded authentication socket. The returned value points to
2830 auth_get_socket_name(void)
2832 return auth_sock_name;
2835 /* removes the agent forwarding socket */
2838 auth_sock_cleanup_proc(void *_pw)
2840 struct passwd *pw = _pw;
2842 if (auth_sock_name) {
2843 temporarily_use_uid(pw);
2844 unlink(auth_sock_name);
2845 rmdir(auth_sock_dir);
2846 auth_sock_name = NULL;
2852 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2853 * This starts forwarding authentication requests.
2857 auth_input_request_forwarding(struct passwd * pw)
2861 struct sockaddr_un sunaddr;
2863 if (auth_get_socket_name() != NULL) {
2864 error("authentication forwarding requested twice.");
2868 /* Temporarily drop privileged uid for mkdir/bind. */
2869 temporarily_use_uid(pw);
2871 /* Allocate a buffer for the socket name, and format the name. */
2872 auth_sock_name = xmalloc(MAXPATHLEN);
2873 auth_sock_dir = xmalloc(MAXPATHLEN);
2874 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2876 /* Create private directory for socket */
2877 if (mkdtemp(auth_sock_dir) == NULL) {
2878 packet_send_debug("Agent forwarding disabled: "
2879 "mkdtemp() failed: %.100s", strerror(errno));
2881 xfree(auth_sock_name);
2882 xfree(auth_sock_dir);
2883 auth_sock_name = NULL;
2884 auth_sock_dir = NULL;
2887 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2888 auth_sock_dir, (int) getpid());
2890 /* delete agent socket on fatal() */
2891 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2893 /* Create the socket. */
2894 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2896 packet_disconnect("socket: %.100s", strerror(errno));
2898 /* Bind it to the name. */
2899 memset(&sunaddr, 0, sizeof(sunaddr));
2900 sunaddr.sun_family = AF_UNIX;
2901 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
2903 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2904 packet_disconnect("bind: %.100s", strerror(errno));
2906 /* Restore the privileged uid. */
2909 /* Start listening on the socket. */
2910 if (listen(sock, 5) < 0)
2911 packet_disconnect("listen: %.100s", strerror(errno));
2913 /* Allocate a channel for the authentication agent socket. */
2914 nc = channel_new("auth socket",
2915 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2916 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2917 0, xstrdup("auth socket"), 1);
2919 error("auth_input_request_forwarding: channel_new failed");
2920 auth_sock_cleanup_proc(pw);
2921 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2925 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2929 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2932 auth_input_open_request(int type, int plen, void *ctxt)
2935 int remote_id, sock;
2938 packet_integrity_check(plen, 4, type);
2940 /* Read the remote channel number from the message. */
2941 remote_id = packet_get_int();
2944 * Get a connection to the local authentication agent (this may again
2947 sock = ssh_get_authentication_socket();
2950 * If we could not connect the agent, send an error message back to
2951 * the server. This should never happen unless the agent dies,
2952 * because authentication forwarding is only enabled if we have an
2956 name = xstrdup("authentication agent connection");
2957 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2958 -1, 0, 0, 0, name, 1);
2960 error("auth_input_open_request: channel_new failed");
2964 c->remote_id = remote_id;
2969 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2970 packet_put_int(remote_id);
2972 /* Send a confirmation to the remote host. */
2973 debug("Forwarding authentication connection.");
2974 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2975 packet_put_int(remote_id);
2976 packet_put_int(c->self);