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 1.129 2001/06/29 18:40:28 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 */
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 buffer_init(&c->input);
245 buffer_init(&c->output);
246 buffer_init(&c->extended);
247 chan_init_iostates(c);
248 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
252 c->local_window = window;
253 c->local_window_max = window;
254 c->local_consumed = 0;
255 c->local_maxpacket = maxpack;
257 c->remote_name = remote_name;
258 c->remote_window = 0;
259 c->remote_maxpacket = 0;
263 c->dettach_user = NULL;
264 c->input_filter = NULL;
265 debug("channel %d: new [%s]", found, remote_name);
269 /* Close all channel fd/socket. */
272 channel_close_fds(Channel *c)
274 debug3("channel_close_fds: channel %d: r %d w %d e %d",
275 c->self, c->rfd, c->wfd, c->efd);
295 /* Free the channel and close its fd/socket. */
298 channel_free(Channel *c)
303 for (n = 0, i = 0; i < channels_alloc; i++)
306 debug("channel_free: channel %d: %s, nchannels %d", c->self,
307 c->remote_name ? c->remote_name : "???", n);
309 s = channel_open_message();
310 debug3("channel_free: status: %s", s);
313 if (c->dettach_user != NULL) {
314 debug("channel_free: channel %d: dettaching channel user", c->self);
315 c->dettach_user(c->self, NULL);
318 shutdown(c->sock, SHUT_RDWR);
319 channel_close_fds(c);
320 buffer_free(&c->input);
321 buffer_free(&c->output);
322 buffer_free(&c->extended);
323 if (c->remote_name) {
324 xfree(c->remote_name);
325 c->remote_name = NULL;
327 channels[c->self] = NULL;
332 channel_free_all(void)
336 for (i = 0; i < channels_alloc; i++)
337 if (channels[i] != NULL)
338 channel_free(channels[i]);
342 * Closes the sockets/fds of all channels. This is used to close extra file
343 * descriptors after a fork.
351 for (i = 0; i < channels_alloc; i++)
352 if (channels[i] != NULL)
353 channel_close_fds(channels[i]);
357 * Returns true if no channel has too much buffered data, and false if one or
358 * more channel is overfull.
362 channel_not_very_much_buffered_data()
367 for (i = 0; i < channels_alloc; i++) {
369 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
370 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
371 debug("channel %d: big input buffer %d",
372 c->self, buffer_len(&c->input));
375 if (buffer_len(&c->output) > packet_get_maxsize()) {
376 debug("channel %d: big output buffer %d",
377 c->self, buffer_len(&c->output));
385 /* Returns true if any channel is still open. */
393 for (i = 0; i < channels_alloc; i++) {
398 case SSH_CHANNEL_X11_LISTENER:
399 case SSH_CHANNEL_PORT_LISTENER:
400 case SSH_CHANNEL_RPORT_LISTENER:
401 case SSH_CHANNEL_CLOSED:
402 case SSH_CHANNEL_AUTH_SOCKET:
403 case SSH_CHANNEL_DYNAMIC:
404 case SSH_CHANNEL_CONNECTING:
405 case SSH_CHANNEL_ZOMBIE:
407 case SSH_CHANNEL_LARVAL:
409 fatal("cannot happen: SSH_CHANNEL_LARVAL");
411 case SSH_CHANNEL_OPENING:
412 case SSH_CHANNEL_OPEN:
413 case SSH_CHANNEL_X11_OPEN:
415 case SSH_CHANNEL_INPUT_DRAINING:
416 case SSH_CHANNEL_OUTPUT_DRAINING:
418 fatal("cannot happen: OUT_DRAIN");
421 fatal("channel_still_open: bad channel type %d", c->type);
428 /* Returns the id of an open channel suitable for keepaliving */
436 for (i = 0; i < channels_alloc; i++) {
441 case SSH_CHANNEL_CLOSED:
442 case SSH_CHANNEL_DYNAMIC:
443 case SSH_CHANNEL_X11_LISTENER:
444 case SSH_CHANNEL_PORT_LISTENER:
445 case SSH_CHANNEL_RPORT_LISTENER:
446 case SSH_CHANNEL_OPENING:
447 case SSH_CHANNEL_CONNECTING:
448 case SSH_CHANNEL_ZOMBIE:
450 case SSH_CHANNEL_LARVAL:
451 case SSH_CHANNEL_AUTH_SOCKET:
452 case SSH_CHANNEL_OPEN:
453 case SSH_CHANNEL_X11_OPEN:
455 case SSH_CHANNEL_INPUT_DRAINING:
456 case SSH_CHANNEL_OUTPUT_DRAINING:
458 fatal("cannot happen: OUT_DRAIN");
461 fatal("channel_find_open: bad channel type %d", c->type);
470 * Returns a message describing the currently open forwarded connections,
471 * suitable for sending to the client. The message contains crlf pairs for
476 channel_open_message()
483 buffer_init(&buffer);
484 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
485 buffer_append(&buffer, buf, strlen(buf));
486 for (i = 0; i < channels_alloc; i++) {
491 case SSH_CHANNEL_X11_LISTENER:
492 case SSH_CHANNEL_PORT_LISTENER:
493 case SSH_CHANNEL_RPORT_LISTENER:
494 case SSH_CHANNEL_CLOSED:
495 case SSH_CHANNEL_AUTH_SOCKET:
496 case SSH_CHANNEL_ZOMBIE:
498 case SSH_CHANNEL_LARVAL:
499 case SSH_CHANNEL_OPENING:
500 case SSH_CHANNEL_CONNECTING:
501 case SSH_CHANNEL_DYNAMIC:
502 case SSH_CHANNEL_OPEN:
503 case SSH_CHANNEL_X11_OPEN:
504 case SSH_CHANNEL_INPUT_DRAINING:
505 case SSH_CHANNEL_OUTPUT_DRAINING:
506 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
507 c->self, c->remote_name,
508 c->type, c->remote_id,
509 c->istate, buffer_len(&c->input),
510 c->ostate, buffer_len(&c->output),
512 buffer_append(&buffer, buf, strlen(buf));
515 fatal("channel_open_message: bad channel type %d", c->type);
519 buffer_append(&buffer, "\0", 1);
520 cp = xstrdup(buffer_ptr(&buffer));
521 buffer_free(&buffer);
526 channel_send_open(int id)
528 Channel *c = channel_lookup(id);
530 log("channel_send_open: %d: bad id", id);
533 debug("send channel open %d", id);
534 packet_start(SSH2_MSG_CHANNEL_OPEN);
535 packet_put_cstring(c->ctype);
536 packet_put_int(c->self);
537 packet_put_int(c->local_window);
538 packet_put_int(c->local_maxpacket);
543 channel_request(int id, char *service, int wantconfirm)
545 channel_request_start(id, service, wantconfirm);
547 debug("channel request %d: %s", id, service) ;
550 channel_request_start(int id, char *service, int wantconfirm)
552 Channel *c = channel_lookup(id);
554 log("channel_request: %d: bad id", id);
557 packet_start(SSH2_MSG_CHANNEL_REQUEST);
558 packet_put_int(c->remote_id);
559 packet_put_cstring(service);
560 packet_put_char(wantconfirm);
563 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
565 Channel *c = channel_lookup(id);
567 log("channel_register_callback: %d: bad id", id);
575 channel_register_cleanup(int id, channel_callback_fn *fn)
577 Channel *c = channel_lookup(id);
579 log("channel_register_cleanup: %d: bad id", id);
582 c->dettach_user = fn;
585 channel_cancel_cleanup(int id)
587 Channel *c = channel_lookup(id);
589 log("channel_cancel_cleanup: %d: bad id", id);
592 c->dettach_user = NULL;
595 channel_register_filter(int id, channel_filter_fn *fn)
597 Channel *c = channel_lookup(id);
599 log("channel_register_filter: %d: bad id", id);
602 c->input_filter = fn;
606 channel_set_fds(int id, int rfd, int wfd, int efd,
607 int extusage, int nonblock)
609 Channel *c = channel_lookup(id);
610 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
611 fatal("channel_activate for non-larval channel %d.", id);
612 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
613 c->type = SSH_CHANNEL_OPEN;
614 /* XXX window size? */
615 c->local_window = c->local_window_max = c->local_maxpacket * 2;
616 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
617 packet_put_int(c->remote_id);
618 packet_put_int(c->local_window);
623 * 'channel_pre*' are called just before select() to add any bits relevant to
624 * channels in the select bitmasks.
627 * 'channel_post*': perform any appropriate operations for channels which
628 * have events pending.
630 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
631 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
632 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
635 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
637 FD_SET(c->sock, readset);
641 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
643 debug3("channel %d: waiting for connection", c->self);
644 FD_SET(c->sock, writeset);
648 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
650 if (buffer_len(&c->input) < packet_get_maxsize())
651 FD_SET(c->sock, readset);
652 if (buffer_len(&c->output) > 0)
653 FD_SET(c->sock, writeset);
657 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
659 /* test whether sockets are 'alive' for read/write */
660 if (c->istate == CHAN_INPUT_OPEN)
661 if (buffer_len(&c->input) < packet_get_maxsize())
662 FD_SET(c->sock, readset);
663 if (c->ostate == CHAN_OUTPUT_OPEN ||
664 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
665 if (buffer_len(&c->output) > 0) {
666 FD_SET(c->sock, writeset);
667 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
674 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
676 if (c->istate == CHAN_INPUT_OPEN &&
677 c->remote_window > 0 &&
678 buffer_len(&c->input) < c->remote_window)
679 FD_SET(c->rfd, readset);
680 if (c->ostate == CHAN_OUTPUT_OPEN ||
681 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
682 if (buffer_len(&c->output) > 0) {
683 FD_SET(c->wfd, writeset);
684 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
688 /** XXX check close conditions, too */
690 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
691 buffer_len(&c->extended) > 0)
692 FD_SET(c->efd, writeset);
693 else if (c->extended_usage == CHAN_EXTENDED_READ &&
694 buffer_len(&c->extended) < c->remote_window)
695 FD_SET(c->efd, readset);
700 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
702 if (buffer_len(&c->input) == 0) {
703 packet_start(SSH_MSG_CHANNEL_CLOSE);
704 packet_put_int(c->remote_id);
706 c->type = SSH_CHANNEL_CLOSED;
707 debug("channel %d: closing after input drain.", c->self);
712 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
714 if (buffer_len(&c->output) == 0)
717 FD_SET(c->sock, writeset);
721 * This is a special state for X11 authentication spoofing. An opened X11
722 * connection (when authentication spoofing is being done) remains in this
723 * state until the first packet has been completely read. The authentication
724 * data in that packet is then substituted by the real data if it matches the
725 * fake data, and the channel is put into normal mode.
726 * XXX All this happens at the client side.
727 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
730 x11_open_helper(Buffer *b)
733 u_int proto_len, data_len;
735 /* Check if the fixed size part of the packet is in buffer. */
736 if (buffer_len(b) < 12)
739 /* Parse the lengths of variable-length fields. */
740 ucp = (u_char *) buffer_ptr(b);
741 if (ucp[0] == 0x42) { /* Byte order MSB first. */
742 proto_len = 256 * ucp[6] + ucp[7];
743 data_len = 256 * ucp[8] + ucp[9];
744 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
745 proto_len = ucp[6] + 256 * ucp[7];
746 data_len = ucp[8] + 256 * ucp[9];
748 debug("Initial X11 packet contains bad byte order byte: 0x%x",
753 /* Check if the whole packet is in buffer. */
755 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
758 /* Check if authentication protocol matches. */
759 if (proto_len != strlen(x11_saved_proto) ||
760 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
761 debug("X11 connection uses different authentication protocol.");
764 /* Check if authentication data matches our fake data. */
765 if (data_len != x11_fake_data_len ||
766 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
767 x11_fake_data, x11_fake_data_len) != 0) {
768 debug("X11 auth data does not match fake data.");
771 /* Check fake data length */
772 if (x11_fake_data_len != x11_saved_data_len) {
773 error("X11 fake_data_len %d != saved_data_len %d",
774 x11_fake_data_len, x11_saved_data_len);
778 * Received authentication protocol and data match
779 * our fake data. Substitute the fake data with real
782 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
783 x11_saved_data, x11_saved_data_len);
788 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
790 int ret = x11_open_helper(&c->output);
792 /* Start normal processing for the channel. */
793 c->type = SSH_CHANNEL_OPEN;
794 channel_pre_open_13(c, readset, writeset);
795 } else if (ret == -1) {
797 * We have received an X11 connection that has bad
798 * authentication information.
800 log("X11 connection rejected because of wrong authentication.");
801 buffer_clear(&c->input);
802 buffer_clear(&c->output);
805 c->type = SSH_CHANNEL_CLOSED;
806 packet_start(SSH_MSG_CHANNEL_CLOSE);
807 packet_put_int(c->remote_id);
813 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
815 int ret = x11_open_helper(&c->output);
817 c->type = SSH_CHANNEL_OPEN;
819 channel_pre_open_20(c, readset, writeset);
821 channel_pre_open_15(c, readset, writeset);
822 } else if (ret == -1) {
823 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
824 chan_read_failed(c); /** force close? */
825 chan_write_failed(c);
826 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
830 /* try to decode a socks4 header */
832 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
835 int len, have, i, found;
841 struct in_addr dest_addr;
844 debug2("channel %d: decode socks4", c->self);
846 have = buffer_len(&c->input);
847 len = sizeof(s4_req);
850 p = buffer_ptr(&c->input);
851 for (found = 0, i = len; i < have; i++) {
857 /* the peer is probably sending garbage */
858 debug("channel %d: decode socks4: too long",
865 buffer_get(&c->input, (char *)&s4_req.version, 1);
866 buffer_get(&c->input, (char *)&s4_req.command, 1);
867 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
868 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
869 have = buffer_len(&c->input);
870 p = buffer_ptr(&c->input);
872 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
874 fatal("channel %d: decode socks4: len %d > have %d",
876 strlcpy(username, p, sizeof(username));
877 buffer_consume(&c->input, len);
878 buffer_consume(&c->input, 1); /* trailing '\0' */
880 host = inet_ntoa(s4_req.dest_addr);
881 strlcpy(c->path, host, sizeof(c->path));
882 c->host_port = ntohs(s4_req.dest_port);
884 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
885 c->self, host, c->host_port, s4_req.command);
887 if (s4_req.command != 1) {
888 debug("channel %d: cannot handle: socks4 cn %d",
889 c->self, s4_req.command);
892 s4_rsp.version = 0; /* vn: 0 for reply */
893 s4_rsp.command = 90; /* cd: req granted */
894 s4_rsp.dest_port = 0; /* ignored */
895 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
896 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
900 /* dynamic port forwarding */
902 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
907 have = buffer_len(&c->input);
909 debug2("channel %d: pre_dynamic: have %d", c->self, have);
910 /* buffer_dump(&c->input); */
911 /* check if the fixed size part of the packet is in buffer. */
914 FD_SET(c->sock, readset);
917 /* try to guess the protocol */
918 p = buffer_ptr(&c->input);
921 ret = channel_decode_socks4(c, readset, writeset);
929 } else if (ret == 0) {
930 debug2("channel %d: pre_dynamic: need more", c->self);
932 FD_SET(c->sock, readset);
934 /* switch to the next state */
935 c->type = SSH_CHANNEL_OPENING;
936 port_open_helper(c, "direct-tcpip");
940 /* This is our fake X11 server socket. */
942 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
945 struct sockaddr addr;
948 char buf[16384], *remote_ipaddr;
951 if (FD_ISSET(c->sock, readset)) {
952 debug("X11 connection requested.");
953 addrlen = sizeof(addr);
954 newsock = accept(c->sock, &addr, &addrlen);
956 error("accept: %.100s", strerror(errno));
959 remote_ipaddr = get_peer_ipaddr(newsock);
960 remote_port = get_peer_port(newsock);
961 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
962 remote_ipaddr, remote_port);
964 nc = channel_new("accepted x11 socket",
965 SSH_CHANNEL_OPENING, newsock, newsock, -1,
966 c->local_window_max, c->local_maxpacket,
970 xfree(remote_ipaddr);
974 packet_start(SSH2_MSG_CHANNEL_OPEN);
975 packet_put_cstring("x11");
976 packet_put_int(nc->self);
977 packet_put_int(c->local_window_max);
978 packet_put_int(c->local_maxpacket);
979 /* originator ipaddr and port */
980 packet_put_cstring(remote_ipaddr);
981 if (datafellows & SSH_BUG_X11FWD) {
982 debug("ssh2 x11 bug compat mode");
984 packet_put_int(remote_port);
988 packet_start(SSH_SMSG_X11_OPEN);
989 packet_put_int(nc->self);
990 if (packet_get_protocol_flags() &
991 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
992 packet_put_cstring(buf);
995 xfree(remote_ipaddr);
1000 port_open_helper(Channel *c, char *rtype)
1004 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1005 u_short remote_port = get_peer_port(c->sock);
1007 direct = (strcmp(rtype, "direct-tcpip") == 0);
1009 snprintf(buf, sizeof buf,
1010 "%s: listening port %d for %.100s port %d, "
1011 "connect from %.200s port %d",
1012 rtype, c->listening_port, c->path, c->host_port,
1013 remote_ipaddr, remote_port);
1015 xfree(c->remote_name);
1016 c->remote_name = xstrdup(buf);
1019 packet_start(SSH2_MSG_CHANNEL_OPEN);
1020 packet_put_cstring(rtype);
1021 packet_put_int(c->self);
1022 packet_put_int(c->local_window_max);
1023 packet_put_int(c->local_maxpacket);
1025 /* target host, port */
1026 packet_put_cstring(c->path);
1027 packet_put_int(c->host_port);
1029 /* listen address, port */
1030 packet_put_cstring(c->path);
1031 packet_put_int(c->listening_port);
1033 /* originator host and port */
1034 packet_put_cstring(remote_ipaddr);
1035 packet_put_int(remote_port);
1038 packet_start(SSH_MSG_PORT_OPEN);
1039 packet_put_int(c->self);
1040 packet_put_cstring(c->path);
1041 packet_put_int(c->host_port);
1042 if (packet_get_protocol_flags() &
1043 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1044 packet_put_cstring(c->remote_name);
1047 xfree(remote_ipaddr);
1051 * This socket is listening for connections to a forwarded TCP/IP port.
1054 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1057 struct sockaddr addr;
1058 int newsock, nextstate;
1062 if (FD_ISSET(c->sock, readset)) {
1063 debug("Connection to port %d forwarding "
1064 "to %.100s port %d requested.",
1065 c->listening_port, c->path, c->host_port);
1067 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
1068 "forwarded-tcpip" : "direct-tcpip";
1069 nextstate = (c->host_port == 0 &&
1070 c->type != SSH_CHANNEL_RPORT_LISTENER) ?
1071 SSH_CHANNEL_DYNAMIC : SSH_CHANNEL_OPENING;
1073 addrlen = sizeof(addr);
1074 newsock = accept(c->sock, &addr, &addrlen);
1076 error("accept: %.100s", strerror(errno));
1079 nc = channel_new(rtype,
1080 nextstate, newsock, newsock, -1,
1081 c->local_window_max, c->local_maxpacket,
1082 0, xstrdup(rtype), 1);
1084 error("channel_post_port_listener: no new channel:");
1088 nc->listening_port = c->listening_port;
1089 nc->host_port = c->host_port;
1090 strlcpy(nc->path, c->path, sizeof(nc->path));
1092 if (nextstate != SSH_CHANNEL_DYNAMIC)
1093 port_open_helper(nc, rtype);
1098 * This is the authentication agent socket listening for connections from
1102 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1107 struct sockaddr addr;
1110 if (FD_ISSET(c->sock, readset)) {
1111 addrlen = sizeof(addr);
1112 newsock = accept(c->sock, &addr, &addrlen);
1114 error("accept from auth socket: %.100s", strerror(errno));
1117 name = xstrdup("accepted auth socket");
1118 nc = channel_new("accepted auth socket",
1119 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1120 c->local_window_max, c->local_maxpacket,
1123 error("channel_post_auth_listener: channel_new failed");
1128 packet_start(SSH2_MSG_CHANNEL_OPEN);
1129 packet_put_cstring("auth-agent@openssh.com");
1130 packet_put_int(nc->self);
1131 packet_put_int(c->local_window_max);
1132 packet_put_int(c->local_maxpacket);
1134 packet_start(SSH_SMSG_AGENT_OPEN);
1135 packet_put_int(nc->self);
1142 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1145 socklen_t sz = sizeof(err);
1147 if (FD_ISSET(c->sock, writeset)) {
1148 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1151 error("getsockopt SO_ERROR failed");
1154 debug("channel %d: connected", c->self);
1155 c->type = SSH_CHANNEL_OPEN;
1157 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1158 packet_put_int(c->remote_id);
1159 packet_put_int(c->self);
1160 packet_put_int(c->local_window);
1161 packet_put_int(c->local_maxpacket);
1163 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1164 packet_put_int(c->remote_id);
1165 packet_put_int(c->self);
1168 debug("channel %d: not connected: %s",
1169 c->self, strerror(err));
1171 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1172 packet_put_int(c->remote_id);
1173 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1174 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1175 packet_put_cstring(strerror(err));
1176 packet_put_cstring("");
1179 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1180 packet_put_int(c->remote_id);
1189 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1195 FD_ISSET(c->rfd, readset)) {
1196 len = read(c->rfd, buf, sizeof(buf));
1197 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1200 debug("channel %d: read<=0 rfd %d len %d",
1201 c->self, c->rfd, len);
1202 if (c->type != SSH_CHANNEL_OPEN) {
1203 debug("channel %d: not open", c->self);
1206 } else if (compat13) {
1207 buffer_consume(&c->output, buffer_len(&c->output));
1208 c->type = SSH_CHANNEL_INPUT_DRAINING;
1209 debug("channel %d: input draining.", c->self);
1211 chan_read_failed(c);
1215 if(c->input_filter != NULL) {
1216 if (c->input_filter(c, buf, len) == -1) {
1217 debug("channel %d: filter stops", c->self);
1218 chan_read_failed(c);
1221 buffer_append(&c->input, buf, len);
1227 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1232 /* Send buffered output data to the socket. */
1234 FD_ISSET(c->wfd, writeset) &&
1235 buffer_len(&c->output) > 0) {
1236 len = write(c->wfd, buffer_ptr(&c->output),
1237 buffer_len(&c->output));
1238 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1241 if (c->type != SSH_CHANNEL_OPEN) {
1242 debug("channel %d: not open", c->self);
1245 } else if (compat13) {
1246 buffer_consume(&c->output, buffer_len(&c->output));
1247 debug("channel %d: input draining.", c->self);
1248 c->type = SSH_CHANNEL_INPUT_DRAINING;
1250 chan_write_failed(c);
1254 if (compat20 && c->isatty) {
1255 if (tcgetattr(c->wfd, &tio) == 0 &&
1256 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1258 * Simulate echo to reduce the impact of
1259 * traffic analysis. We need to match the
1260 * size of a SSH2_MSG_CHANNEL_DATA message
1261 * (4 byte channel id + data)
1263 packet_send_ignore(4 + len);
1267 buffer_consume(&c->output, len);
1268 if (compat20 && len > 0) {
1269 c->local_consumed += len;
1275 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1280 /** XXX handle drain efd, too */
1282 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1283 FD_ISSET(c->efd, writeset) &&
1284 buffer_len(&c->extended) > 0) {
1285 len = write(c->efd, buffer_ptr(&c->extended),
1286 buffer_len(&c->extended));
1287 debug2("channel %d: written %d to efd %d",
1288 c->self, len, c->efd);
1289 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1292 debug2("channel %d: closing write-efd %d",
1297 buffer_consume(&c->extended, len);
1298 c->local_consumed += len;
1300 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1301 FD_ISSET(c->efd, readset)) {
1302 len = read(c->efd, buf, sizeof(buf));
1303 debug2("channel %d: read %d from efd %d",
1304 c->self, len, c->efd);
1305 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1308 debug2("channel %d: closing read-efd %d",
1313 buffer_append(&c->extended, buf, len);
1320 channel_check_window(Channel *c)
1322 if (c->type == SSH_CHANNEL_OPEN &&
1323 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1324 c->local_window < c->local_window_max/2 &&
1325 c->local_consumed > 0) {
1326 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1327 packet_put_int(c->remote_id);
1328 packet_put_int(c->local_consumed);
1330 debug2("channel %d: window %d sent adjust %d",
1331 c->self, c->local_window,
1333 c->local_window += c->local_consumed;
1334 c->local_consumed = 0;
1340 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1342 channel_handle_rfd(c, readset, writeset);
1343 channel_handle_wfd(c, readset, writeset);
1347 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1349 channel_handle_rfd(c, readset, writeset);
1350 channel_handle_wfd(c, readset, writeset);
1351 channel_handle_efd(c, readset, writeset);
1353 channel_check_window(c);
1357 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1360 /* Send buffered output data to the socket. */
1361 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1362 len = write(c->sock, buffer_ptr(&c->output),
1363 buffer_len(&c->output));
1365 buffer_consume(&c->output, buffer_len(&c->output));
1367 buffer_consume(&c->output, len);
1372 channel_handler_init_20(void)
1374 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1375 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1376 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1377 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1378 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1379 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1380 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1381 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1383 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1384 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1385 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1386 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1387 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1388 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1389 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1393 channel_handler_init_13(void)
1395 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1396 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1397 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1398 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1399 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1400 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1401 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1402 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1403 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1405 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1406 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1407 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1408 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1409 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1410 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1411 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1415 channel_handler_init_15(void)
1417 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1418 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1419 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1420 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1421 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1422 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1423 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1425 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1426 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1427 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1428 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1429 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1430 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1434 channel_handler_init(void)
1437 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1438 channel_pre[i] = NULL;
1439 channel_post[i] = NULL;
1442 channel_handler_init_20();
1444 channel_handler_init_13();
1446 channel_handler_init_15();
1450 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1452 static int did_init = 0;
1457 channel_handler_init();
1460 for (i = 0; i < channels_alloc; i++) {
1464 if (ftab[c->type] != NULL)
1465 (*ftab[c->type])(c, readset, writeset);
1466 if (chan_is_dead(c)) {
1468 * we have to remove the fd's from the select mask
1469 * before the channels are free'd and the fd's are
1473 FD_CLR(c->wfd, writeset);
1475 FD_CLR(c->rfd, readset);
1477 if (c->extended_usage == CHAN_EXTENDED_READ)
1478 FD_CLR(c->efd, readset);
1479 if (c->extended_usage == CHAN_EXTENDED_WRITE)
1480 FD_CLR(c->efd, writeset);
1488 * Allocate/update select bitmasks and add any bits relevant to channels in
1492 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1498 n = MAX(*maxfdp, channel_max_fd);
1500 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1501 if (*readsetp == NULL || n > *maxfdp) {
1506 *readsetp = xmalloc(sz);
1507 *writesetp = xmalloc(sz);
1510 memset(*readsetp, 0, sz);
1511 memset(*writesetp, 0, sz);
1514 channel_handler(channel_pre, *readsetp, *writesetp);
1518 * After select, perform any appropriate operations for channels which have
1522 channel_after_select(fd_set * readset, fd_set * writeset)
1524 channel_handler(channel_post, readset, writeset);
1528 /* If there is data to send to the connection, enqueue some of it now. */
1531 channel_output_poll()
1536 for (i = 0; i < channels_alloc; i++) {
1542 * We are only interested in channels that can have buffered
1546 if (c->type != SSH_CHANNEL_OPEN &&
1547 c->type != SSH_CHANNEL_INPUT_DRAINING)
1550 if (c->type != SSH_CHANNEL_OPEN)
1554 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1555 /* XXX is this true? */
1556 debug2("channel %d: no data after CLOSE", c->self);
1560 /* Get the amount of buffered data for this channel. */
1561 if ((c->istate == CHAN_INPUT_OPEN ||
1562 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1563 (len = buffer_len(&c->input)) > 0) {
1565 * Send some data for the other side over the secure
1569 if (len > c->remote_window)
1570 len = c->remote_window;
1571 if (len > c->remote_maxpacket)
1572 len = c->remote_maxpacket;
1574 if (packet_is_interactive()) {
1578 /* Keep the packets at reasonable size. */
1579 if (len > packet_get_maxsize()/2)
1580 len = packet_get_maxsize()/2;
1584 packet_start(compat20 ?
1585 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1586 packet_put_int(c->remote_id);
1587 packet_put_string(buffer_ptr(&c->input), len);
1589 buffer_consume(&c->input, len);
1590 c->remote_window -= len;
1592 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1594 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1596 * input-buffer is empty and read-socket shutdown:
1597 * tell peer, that we will not send more data: send IEOF
1601 /* Send extended data, i.e. stderr */
1603 c->remote_window > 0 &&
1604 (len = buffer_len(&c->extended)) > 0 &&
1605 c->extended_usage == CHAN_EXTENDED_READ) {
1606 debug2("channel %d: rwin %d elen %d euse %d",
1607 c->self, c->remote_window, buffer_len(&c->extended),
1609 if (len > c->remote_window)
1610 len = c->remote_window;
1611 if (len > c->remote_maxpacket)
1612 len = c->remote_maxpacket;
1613 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1614 packet_put_int(c->remote_id);
1615 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1616 packet_put_string(buffer_ptr(&c->extended), len);
1618 buffer_consume(&c->extended, len);
1619 c->remote_window -= len;
1620 debug2("channel %d: sent ext data %d", c->self, len);
1626 /* -- protocol input */
1629 channel_input_data(int type, int plen, void *ctxt)
1636 /* Get the channel number and verify it. */
1637 id = packet_get_int();
1638 c = channel_lookup(id);
1640 packet_disconnect("Received data for nonexistent channel %d.", id);
1642 /* Ignore any data for non-open channels (might happen on close) */
1643 if (c->type != SSH_CHANNEL_OPEN &&
1644 c->type != SSH_CHANNEL_X11_OPEN)
1647 /* same for protocol 1.5 if output end is no longer open */
1648 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1652 data = packet_get_string(&data_len);
1656 if (data_len > c->local_maxpacket) {
1657 log("channel %d: rcvd big packet %d, maxpack %d",
1658 c->self, data_len, c->local_maxpacket);
1660 if (data_len > c->local_window) {
1661 log("channel %d: rcvd too much data %d, win %d",
1662 c->self, data_len, c->local_window);
1666 c->local_window -= data_len;
1668 packet_integrity_check(plen, 4 + 4 + data_len, type);
1670 buffer_append(&c->output, data, data_len);
1675 channel_input_extended_data(int type, int plen, void *ctxt)
1683 /* Get the channel number and verify it. */
1684 id = packet_get_int();
1685 c = channel_lookup(id);
1688 packet_disconnect("Received extended_data for bad channel %d.", id);
1689 if (c->type != SSH_CHANNEL_OPEN) {
1690 log("channel %d: ext data for non open", id);
1693 tcode = packet_get_int();
1695 c->extended_usage != CHAN_EXTENDED_WRITE ||
1696 tcode != SSH2_EXTENDED_DATA_STDERR) {
1697 log("channel %d: bad ext data", c->self);
1700 data = packet_get_string(&data_len);
1702 if (data_len > c->local_window) {
1703 log("channel %d: rcvd too much extended_data %d, win %d",
1704 c->self, data_len, c->local_window);
1708 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1709 c->local_window -= data_len;
1710 buffer_append(&c->extended, data, data_len);
1715 channel_input_ieof(int type, int plen, void *ctxt)
1720 packet_integrity_check(plen, 4, type);
1722 id = packet_get_int();
1723 c = channel_lookup(id);
1725 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1730 channel_input_close(int type, int plen, void *ctxt)
1735 packet_integrity_check(plen, 4, type);
1737 id = packet_get_int();
1738 c = channel_lookup(id);
1740 packet_disconnect("Received close for nonexistent channel %d.", id);
1743 * Send a confirmation that we have closed the channel and no more
1744 * data is coming for it.
1746 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1747 packet_put_int(c->remote_id);
1751 * If the channel is in closed state, we have sent a close request,
1752 * and the other side will eventually respond with a confirmation.
1753 * Thus, we cannot free the channel here, because then there would be
1754 * no-one to receive the confirmation. The channel gets freed when
1755 * the confirmation arrives.
1757 if (c->type != SSH_CHANNEL_CLOSED) {
1759 * Not a closed channel - mark it as draining, which will
1760 * cause it to be freed later.
1762 buffer_consume(&c->input, buffer_len(&c->input));
1763 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1767 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1769 channel_input_oclose(int type, int plen, void *ctxt)
1771 int id = packet_get_int();
1772 Channel *c = channel_lookup(id);
1773 packet_integrity_check(plen, 4, type);
1775 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1776 chan_rcvd_oclose(c);
1780 channel_input_close_confirmation(int type, int plen, void *ctxt)
1782 int id = packet_get_int();
1783 Channel *c = channel_lookup(id);
1787 packet_disconnect("Received close confirmation for "
1788 "out-of-range channel %d.", id);
1789 if (c->type != SSH_CHANNEL_CLOSED)
1790 packet_disconnect("Received close confirmation for "
1791 "non-closed channel %d (type %d).", id, c->type);
1796 channel_input_open_confirmation(int type, int plen, void *ctxt)
1802 packet_integrity_check(plen, 4 + 4, type);
1804 id = packet_get_int();
1805 c = channel_lookup(id);
1807 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1808 packet_disconnect("Received open confirmation for "
1809 "non-opening channel %d.", id);
1810 remote_id = packet_get_int();
1811 /* Record the remote channel number and mark that the channel is now open. */
1812 c->remote_id = remote_id;
1813 c->type = SSH_CHANNEL_OPEN;
1816 c->remote_window = packet_get_int();
1817 c->remote_maxpacket = packet_get_int();
1819 if (c->cb_fn != NULL && c->cb_event == type) {
1820 debug2("callback start");
1821 c->cb_fn(c->self, c->cb_arg);
1822 debug2("callback done");
1824 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1825 c->remote_window, c->remote_maxpacket);
1830 reason2txt(int reason)
1833 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1834 return "administratively prohibited";
1835 case SSH2_OPEN_CONNECT_FAILED:
1836 return "connect failed";
1837 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1838 return "unknown channel type";
1839 case SSH2_OPEN_RESOURCE_SHORTAGE:
1840 return "resource shortage";
1842 return "unknown reason";
1846 channel_input_open_failure(int type, int plen, void *ctxt)
1849 char *msg = NULL, *lang = NULL;
1853 packet_integrity_check(plen, 4, type);
1855 id = packet_get_int();
1856 c = channel_lookup(id);
1858 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1859 packet_disconnect("Received open failure for "
1860 "non-opening channel %d.", id);
1862 reason = packet_get_int();
1863 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1864 msg = packet_get_string(NULL);
1865 lang = packet_get_string(NULL);
1868 log("channel %d: open failed: %s%s%s", id,
1869 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1875 /* Free the channel. This will also close the socket. */
1880 channel_input_channel_request(int type, int plen, void *ctxt)
1885 id = packet_get_int();
1886 c = channel_lookup(id);
1889 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1890 packet_disconnect("Received request for "
1891 "non-open channel %d.", id);
1892 if (c->cb_fn != NULL && c->cb_event == type) {
1893 debug2("callback start");
1894 c->cb_fn(c->self, c->cb_arg);
1895 debug2("callback done");
1897 char *service = packet_get_string(NULL);
1898 debug("channel %d: rcvd request for %s", c->self, service);
1899 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1905 channel_input_window_adjust(int type, int plen, void *ctxt)
1913 /* Get the channel number and verify it. */
1914 id = packet_get_int();
1915 c = channel_lookup(id);
1917 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1918 log("Received window adjust for "
1919 "non-open channel %d.", id);
1922 adjust = packet_get_int();
1924 debug2("channel %d: rcvd adjust %d", id, adjust);
1925 c->remote_window += adjust;
1929 channel_input_port_open(int type, int plen, void *ctxt)
1933 char *host, *originator_string;
1934 int remote_id, sock = -1;
1936 remote_id = packet_get_int();
1937 host = packet_get_string(NULL);
1938 host_port = packet_get_int();
1940 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
1941 originator_string = packet_get_string(NULL);
1943 originator_string = xstrdup("unknown (remote did not supply name)");
1946 sock = channel_connect_to(host, host_port);
1948 c = channel_new("connected socket",
1949 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
1950 originator_string, 1);
1952 error("channel_input_port_open: channel_new failed");
1955 c->remote_id = remote_id;
1959 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1960 packet_put_int(remote_id);
1967 /* -- tcp forwarding */
1970 * Initiate forwarding of connections to local port "port" through the secure
1971 * channel to host:port from remote side.
1974 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
1975 u_short port_to_connect, int gateway_ports)
1977 return channel_request_forwarding(
1979 host_to_connect, port_to_connect,
1980 gateway_ports, /*remote_fwd*/ 0);
1984 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
1985 * (SSH_CHANNEL_RPORT_LISTENER).
1988 channel_request_forwarding(
1989 const char *listen_address, u_short listen_port,
1990 const char *host_to_connect, u_short port_to_connect,
1991 int gateway_ports, int remote_fwd)
1994 int success, sock, on = 1, type;
1995 struct addrinfo hints, *ai, *aitop;
1996 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1998 struct linger linger;
2003 host = listen_address;
2004 type = SSH_CHANNEL_RPORT_LISTENER;
2006 host = host_to_connect;
2007 type = SSH_CHANNEL_PORT_LISTENER;
2010 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2011 error("Forward host name too long.");
2015 /* XXX listen_address is currently ignored */
2017 * getaddrinfo returns a loopback address if the hostname is
2018 * set to NULL and hints.ai_flags is not AI_PASSIVE
2020 memset(&hints, 0, sizeof(hints));
2021 hints.ai_family = IPv4or6;
2022 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2023 hints.ai_socktype = SOCK_STREAM;
2024 snprintf(strport, sizeof strport, "%d", listen_port);
2025 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2026 packet_disconnect("getaddrinfo: fatal error");
2028 for (ai = aitop; ai; ai = ai->ai_next) {
2029 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2031 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2032 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2033 error("channel_request_forwarding: getnameinfo failed");
2036 /* Create a port to listen for the host. */
2037 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2039 /* this is no error since kernel may not support ipv6 */
2040 verbose("socket: %.100s", strerror(errno));
2044 * Set socket options. We would like the socket to disappear
2045 * as soon as it has been closed for whatever reason.
2047 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2049 linger.l_linger = 5;
2050 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2051 debug("Local forwarding listening on %s port %s.", ntop, strport);
2053 /* Bind the socket to the address. */
2054 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2055 /* address can be in use ipv6 address is already bound */
2057 error("bind: %.100s", strerror(errno));
2059 verbose("bind: %.100s", strerror(errno));
2064 /* Start listening for connections on the socket. */
2065 if (listen(sock, 5) < 0) {
2066 error("listen: %.100s", strerror(errno));
2070 /* Allocate a channel number for the socket. */
2071 c = channel_new("port listener", type, sock, sock, -1,
2072 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2073 0, xstrdup("port listener"), 1);
2075 error("channel_request_forwarding: channel_new failed");
2079 strlcpy(c->path, host, sizeof(c->path));
2080 c->host_port = port_to_connect;
2081 c->listening_port = listen_port;
2085 error("channel_request_forwarding: cannot listen to port: %d",
2087 freeaddrinfo(aitop);
2092 * Initiate forwarding of connections to port "port" on remote host through
2093 * the secure channel to host:port from local side.
2097 channel_request_remote_forwarding(u_short listen_port,
2098 const char *host_to_connect, u_short port_to_connect)
2100 int payload_len, type, success = 0;
2102 /* Record locally that connection to this host/port is permitted. */
2103 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2104 fatal("channel_request_remote_forwarding: too many forwards");
2106 /* Send the forward request to the remote side. */
2108 const char *address_to_bind = "0.0.0.0";
2109 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2110 packet_put_cstring("tcpip-forward");
2111 packet_put_char(0); /* boolean: want reply */
2112 packet_put_cstring(address_to_bind);
2113 packet_put_int(listen_port);
2115 packet_write_wait();
2116 /* Assume that server accepts the request */
2119 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2120 packet_put_int(listen_port);
2121 packet_put_cstring(host_to_connect);
2122 packet_put_int(port_to_connect);
2124 packet_write_wait();
2126 /* Wait for response from the remote side. */
2127 type = packet_read(&payload_len);
2129 case SSH_SMSG_SUCCESS:
2132 case SSH_SMSG_FAILURE:
2133 log("Warning: Server denied remote port forwarding.");
2136 /* Unknown packet */
2137 packet_disconnect("Protocol error for port forward request:"
2138 "received packet type %d.", type);
2142 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2143 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2144 permitted_opens[num_permitted_opens].listen_port = listen_port;
2145 num_permitted_opens++;
2150 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2151 * listening for the port, and sends back a success reply (or disconnect
2152 * message if there was an error). This never returns if there was an error.
2156 channel_input_port_forward_request(int is_root, int gateway_ports)
2158 u_short port, host_port;
2161 /* Get arguments from the packet. */
2162 port = packet_get_int();
2163 hostname = packet_get_string(NULL);
2164 host_port = packet_get_int();
2168 * Check that an unprivileged user is not trying to forward a
2171 if (port < IPPORT_RESERVED && !is_root)
2172 packet_disconnect("Requested forwarding of port %d but user is not root.",
2175 /* Initiate forwarding */
2176 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2178 /* Free the argument string. */
2183 * Permits opening to any host/port if permitted_opens[] is empty. This is
2184 * usually called by the server, because the user could connect to any port
2185 * anyway, and the server has no way to know but to trust the client anyway.
2188 channel_permit_all_opens()
2190 if (num_permitted_opens == 0)
2191 all_opens_permitted = 1;
2195 channel_add_permitted_opens(char *host, int port)
2197 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2198 fatal("channel_request_remote_forwarding: too many forwards");
2199 debug("allow port forwarding to host %s port %d", host, port);
2201 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2202 permitted_opens[num_permitted_opens].port_to_connect = port;
2203 num_permitted_opens++;
2205 all_opens_permitted = 0;
2209 channel_clear_permitted_opens(void)
2213 for (i = 0; i < num_permitted_opens; i++)
2214 xfree(permitted_opens[i].host_to_connect);
2215 num_permitted_opens = 0;
2220 /* return socket to remote host, port */
2222 connect_to(const char *host, u_short port)
2224 struct addrinfo hints, *ai, *aitop;
2225 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2229 memset(&hints, 0, sizeof(hints));
2230 hints.ai_family = IPv4or6;
2231 hints.ai_socktype = SOCK_STREAM;
2232 snprintf(strport, sizeof strport, "%d", port);
2233 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2234 error("connect_to %.100s: unknown host (%s)", host,
2235 gai_strerror(gaierr));
2238 for (ai = aitop; ai; ai = ai->ai_next) {
2239 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2241 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2242 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2243 error("connect_to: getnameinfo failed");
2246 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2248 error("socket: %.100s", strerror(errno));
2251 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2252 fatal("connect_to: F_SETFL: %s", strerror(errno));
2253 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2254 errno != EINPROGRESS) {
2255 error("connect_to %.100s port %s: %.100s", ntop, strport,
2258 continue; /* fail -- try next */
2260 break; /* success */
2263 freeaddrinfo(aitop);
2265 error("connect_to %.100s port %d: failed.", host, port);
2273 channel_connect_by_listen_adress(u_short listen_port)
2277 for (i = 0; i < num_permitted_opens; i++)
2278 if (permitted_opens[i].listen_port == listen_port)
2280 permitted_opens[i].host_to_connect,
2281 permitted_opens[i].port_to_connect);
2282 error("WARNING: Server requests forwarding for unknown listen_port %d",
2287 /* Check if connecting to that port is permitted and connect. */
2289 channel_connect_to(const char *host, u_short port)
2293 permit = all_opens_permitted;
2295 for (i = 0; i < num_permitted_opens; i++)
2296 if (permitted_opens[i].port_to_connect == port &&
2297 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2302 log("Received request to connect to host %.100s port %d, "
2303 "but the request was denied.", host, port);
2306 return connect_to(host, port);
2309 /* -- X11 forwarding */
2312 * Creates an internet domain socket for listening for X11 connections.
2313 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2317 x11_create_display_inet(int screen_number, int x11_display_offset)
2319 int display_number, sock;
2321 struct addrinfo hints, *ai, *aitop;
2322 char strport[NI_MAXSERV];
2323 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2325 char hostname[MAXHOSTNAMELEN];
2327 for (display_number = x11_display_offset;
2328 display_number < MAX_DISPLAYS;
2330 port = 6000 + display_number;
2331 memset(&hints, 0, sizeof(hints));
2332 hints.ai_family = IPv4or6;
2333 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2334 hints.ai_socktype = SOCK_STREAM;
2335 snprintf(strport, sizeof strport, "%d", port);
2336 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2337 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2340 for (ai = aitop; ai; ai = ai->ai_next) {
2341 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2343 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2345 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2346 error("socket: %.100s", strerror(errno));
2349 debug("x11_create_display_inet: Socket family %d not supported",
2354 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2355 debug("bind port %d: %.100s", port, strerror(errno));
2356 shutdown(sock, SHUT_RDWR);
2362 for (n = 0; n < num_socks; n++) {
2363 shutdown(socks[n], SHUT_RDWR);
2369 socks[num_socks++] = sock;
2370 #ifndef DONT_TRY_OTHER_AF
2371 if (num_socks == NUM_SOCKS)
2377 freeaddrinfo(aitop);
2381 if (display_number >= MAX_DISPLAYS) {
2382 error("Failed to allocate internet-domain X11 display socket.");
2385 /* Start listening for connections on the socket. */
2386 for (n = 0; n < num_socks; n++) {
2388 if (listen(sock, 5) < 0) {
2389 error("listen: %.100s", strerror(errno));
2390 shutdown(sock, SHUT_RDWR);
2396 /* Set up a suitable value for the DISPLAY variable. */
2397 if (gethostname(hostname, sizeof(hostname)) < 0)
2398 fatal("gethostname: %.100s", strerror(errno));
2400 #ifdef IPADDR_IN_DISPLAY
2402 * HPUX detects the local hostname in the DISPLAY variable and tries
2403 * to set up a shared memory connection to the server, which it
2404 * incorrectly supposes to be local.
2406 * The workaround - as used in later $$H and other programs - is
2407 * is to set display to the host's IP address.
2411 struct in_addr my_addr;
2413 he = gethostbyname(hostname);
2415 error("[X11-broken-fwd-hostname-workaround] Could not get "
2416 "IP address for hostname %s.", hostname);
2418 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2419 "Could not get IP address for hostname %s.", hostname);
2421 shutdown(sock, SHUT_RDWR);
2427 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2429 /* Set DISPLAY to <ip address>:screen.display */
2430 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2431 display_number, screen_number);
2433 #else /* IPADDR_IN_DISPLAY */
2434 /* Just set DISPLAY to hostname:screen.display */
2435 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2436 display_number, screen_number);
2437 #endif /* IPADDR_IN_DISPLAY */
2439 /* Allocate a channel for each socket. */
2440 for (n = 0; n < num_socks; n++) {
2442 (void) channel_new("x11 listener",
2443 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2444 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2445 0, xstrdup("X11 inet listener"), 1);
2448 /* Return a suitable value for the DISPLAY environment variable. */
2449 return xstrdup(display);
2453 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2457 connect_local_xsocket(u_int dnr)
2459 static const char *const x_sockets[] = {
2461 "/var/X/.X11-unix/X" "%u",
2462 "/usr/spool/sockets/X11/" "%u",
2466 struct sockaddr_un addr;
2467 const char *const * path;
2469 for (path = x_sockets; *path; ++path) {
2470 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2472 error("socket: %.100s", strerror(errno));
2473 memset(&addr, 0, sizeof(addr));
2474 addr.sun_family = AF_UNIX;
2475 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2476 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2480 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2485 x11_connect_display(void)
2487 int display_number, sock = 0;
2488 const char *display;
2489 char buf[1024], *cp;
2490 struct addrinfo hints, *ai, *aitop;
2491 char strport[NI_MAXSERV];
2494 /* Try to open a socket for the local X server. */
2495 display = getenv("DISPLAY");
2497 error("DISPLAY not set.");
2501 * Now we decode the value of the DISPLAY variable and make a
2502 * connection to the real X server.
2506 * Check if it is a unix domain socket. Unix domain displays are in
2507 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2509 if (strncmp(display, "unix:", 5) == 0 ||
2510 display[0] == ':') {
2511 /* Connect to the unix domain socket. */
2512 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2513 error("Could not parse display number from DISPLAY: %.100s",
2517 /* Create a socket. */
2518 sock = connect_local_xsocket(display_number);
2522 /* OK, we now have a connection to the display. */
2526 * Connect to an inet socket. The DISPLAY value is supposedly
2527 * hostname:d[.s], where hostname may also be numeric IP address.
2529 strncpy(buf, display, sizeof(buf));
2530 buf[sizeof(buf) - 1] = 0;
2531 cp = strchr(buf, ':');
2533 error("Could not find ':' in DISPLAY: %.100s", display);
2537 /* buf now contains the host name. But first we parse the display number. */
2538 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2539 error("Could not parse display number from DISPLAY: %.100s",
2544 /* Look up the host address */
2545 memset(&hints, 0, sizeof(hints));
2546 hints.ai_family = IPv4or6;
2547 hints.ai_socktype = SOCK_STREAM;
2548 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2549 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2550 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2553 for (ai = aitop; ai; ai = ai->ai_next) {
2554 /* Create a socket. */
2555 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2557 debug("socket: %.100s", strerror(errno));
2560 /* Connect it to the display. */
2561 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2562 debug("connect %.100s port %d: %.100s", buf,
2563 6000 + display_number, strerror(errno));
2570 freeaddrinfo(aitop);
2572 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2580 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2581 * the remote channel number. We should do whatever we want, and respond
2582 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2586 x11_input_open(int type, int plen, void *ctxt)
2589 int remote_id, sock = 0;
2592 debug("Received X11 open request.");
2594 remote_id = packet_get_int();
2596 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2597 remote_host = packet_get_string(NULL);
2599 remote_host = xstrdup("unknown (remote did not supply name)");
2603 /* Obtain a connection to the real X display. */
2604 sock = x11_connect_display();
2606 /* Allocate a channel for this connection. */
2607 c = channel_new("connected x11 socket",
2608 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2611 error("x11_input_open: channel_new failed");
2614 c->remote_id = remote_id;
2618 /* Send refusal to the remote host. */
2619 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2620 packet_put_int(remote_id);
2622 /* Send a confirmation to the remote host. */
2623 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2624 packet_put_int(remote_id);
2625 packet_put_int(c->self);
2630 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2632 deny_input_open(int type, int plen, void *ctxt)
2634 int rchan = packet_get_int();
2636 case SSH_SMSG_AGENT_OPEN:
2637 error("Warning: ssh server tried agent forwarding.");
2639 case SSH_SMSG_X11_OPEN:
2640 error("Warning: ssh server tried X11 forwarding.");
2643 error("deny_input_open: type %d plen %d", type, plen);
2646 error("Warning: this is probably a break in attempt by a malicious server.");
2647 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2648 packet_put_int(rchan);
2653 * Requests forwarding of X11 connections, generates fake authentication
2654 * data, and enables authentication spoofing.
2655 * This should be called in the client only.
2658 x11_request_forwarding_with_spoofing(int client_session_id,
2659 const char *proto, const char *data)
2661 u_int data_len = (u_int) strlen(data) / 2;
2662 u_int i, value, len;
2668 cp = getenv("DISPLAY");
2670 cp = strchr(cp, ':');
2672 cp = strchr(cp, '.');
2674 screen_number = atoi(cp + 1);
2678 /* Save protocol name. */
2679 x11_saved_proto = xstrdup(proto);
2682 * Extract real authentication data and generate fake data of the
2685 x11_saved_data = xmalloc(data_len);
2686 x11_fake_data = xmalloc(data_len);
2687 for (i = 0; i < data_len; i++) {
2688 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2689 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2691 rand = arc4random();
2692 x11_saved_data[i] = value;
2693 x11_fake_data[i] = rand & 0xff;
2696 x11_saved_data_len = data_len;
2697 x11_fake_data_len = data_len;
2699 /* Convert the fake data into hex. */
2700 len = 2 * data_len + 1;
2701 new_data = xmalloc(len);
2702 for (i = 0; i < data_len; i++)
2703 snprintf(new_data + 2 * i, len - 2 * i,
2704 "%02x", (u_char) x11_fake_data[i]);
2706 /* Send the request packet. */
2708 channel_request_start(client_session_id, "x11-req", 0);
2709 packet_put_char(0); /* XXX bool single connection */
2711 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2713 packet_put_cstring(proto);
2714 packet_put_cstring(new_data);
2715 packet_put_int(screen_number);
2717 packet_write_wait();
2722 /* -- agent forwarding */
2724 /* Sends a message to the server to request authentication fd forwarding. */
2727 auth_request_forwarding()
2729 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2731 packet_write_wait();
2735 * Returns the name of the forwarded authentication socket. Returns NULL if
2736 * there is no forwarded authentication socket. The returned value points to
2741 auth_get_socket_name()
2743 return auth_sock_name;
2746 /* removes the agent forwarding socket */
2749 auth_sock_cleanup_proc(void *_pw)
2751 struct passwd *pw = _pw;
2753 if (auth_sock_name) {
2754 temporarily_use_uid(pw);
2755 unlink(auth_sock_name);
2756 rmdir(auth_sock_dir);
2757 auth_sock_name = NULL;
2763 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2764 * This starts forwarding authentication requests.
2768 auth_input_request_forwarding(struct passwd * pw)
2772 struct sockaddr_un sunaddr;
2774 if (auth_get_socket_name() != NULL) {
2775 error("authentication forwarding requested twice.");
2779 /* Temporarily drop privileged uid for mkdir/bind. */
2780 temporarily_use_uid(pw);
2782 /* Allocate a buffer for the socket name, and format the name. */
2783 auth_sock_name = xmalloc(MAXPATHLEN);
2784 auth_sock_dir = xmalloc(MAXPATHLEN);
2785 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2787 /* Create private directory for socket */
2788 if (mkdtemp(auth_sock_dir) == NULL) {
2789 packet_send_debug("Agent forwarding disabled: "
2790 "mkdtemp() failed: %.100s", strerror(errno));
2792 xfree(auth_sock_name);
2793 xfree(auth_sock_dir);
2794 auth_sock_name = NULL;
2795 auth_sock_dir = NULL;
2798 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2799 auth_sock_dir, (int) getpid());
2801 /* delete agent socket on fatal() */
2802 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2804 /* Create the socket. */
2805 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2807 packet_disconnect("socket: %.100s", strerror(errno));
2809 /* Bind it to the name. */
2810 memset(&sunaddr, 0, sizeof(sunaddr));
2811 sunaddr.sun_family = AF_UNIX;
2812 strncpy(sunaddr.sun_path, auth_sock_name,
2813 sizeof(sunaddr.sun_path));
2815 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2816 packet_disconnect("bind: %.100s", strerror(errno));
2818 /* Restore the privileged uid. */
2821 /* Start listening on the socket. */
2822 if (listen(sock, 5) < 0)
2823 packet_disconnect("listen: %.100s", strerror(errno));
2825 /* Allocate a channel for the authentication agent socket. */
2826 nc = channel_new("auth socket",
2827 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2828 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2829 0, xstrdup("auth socket"), 1);
2831 error("auth_input_request_forwarding: channel_new failed");
2832 auth_sock_cleanup_proc(pw);
2833 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2837 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2841 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2844 auth_input_open_request(int type, int plen, void *ctxt)
2847 int remote_id, sock;
2850 packet_integrity_check(plen, 4, type);
2852 /* Read the remote channel number from the message. */
2853 remote_id = packet_get_int();
2856 * Get a connection to the local authentication agent (this may again
2859 sock = ssh_get_authentication_socket();
2862 * If we could not connect the agent, send an error message back to
2863 * the server. This should never happen unless the agent dies,
2864 * because authentication forwarding is only enabled if we have an
2868 name = xstrdup("authentication agent connection");
2869 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2870 -1, 0, 0, 0, name, 1);
2872 error("auth_input_open_request: channel_new failed");
2876 c->remote_id = remote_id;
2880 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2881 packet_put_int(remote_id);
2883 /* Send a confirmation to the remote host. */
2884 debug("Forwarding authentication connection.");
2885 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2886 packet_put_int(remote_id);
2887 packet_put_int(c->self);