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 1.147 2001/12/08 17:49:28 stevesk Exp $");
57 #include "pathnames.h"
63 * Pointer to an array containing all allocated channels. The array is
64 * dynamically extended as needed.
66 static Channel **channels = NULL;
69 * Size of the channel array. All slots of the array must always be
70 * initialized (at least the type field); unused slots set to NULL
72 static int channels_alloc = 0;
75 * Maximum file descriptor value used in any of the channels. This is
76 * updated in channel_new.
78 static int channel_max_fd = 0;
81 /* -- tcp forwarding */
84 * Data structure for storing which hosts are permitted for forward requests.
85 * The local sides of any remote forwards are stored in this array to prevent
86 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
87 * network (which might be behind a firewall).
90 char *host_to_connect; /* Connect to 'host'. */
91 u_short port_to_connect; /* Connect to 'port'. */
92 u_short listen_port; /* Remote side should listen port number. */
95 /* List of all permitted host/port pairs to connect. */
96 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
98 /* Number of permitted host/port pairs in the array. */
99 static int num_permitted_opens = 0;
101 * If this is true, all opens are permitted. This is the case on the server
102 * on which we have to trust the client anyway, and the user could do
103 * anything after logging in anyway.
105 static int all_opens_permitted = 0;
108 /* -- X11 forwarding */
110 /* Maximum number of fake X11 displays to try. */
111 #define MAX_DISPLAYS 1000
113 /* Saved X11 authentication protocol name. */
114 static char *x11_saved_proto = NULL;
116 /* Saved X11 authentication data. This is the real data. */
117 static char *x11_saved_data = NULL;
118 static u_int x11_saved_data_len = 0;
121 * Fake X11 authentication data. This is what the server will be sending us;
122 * we should replace any occurrences of this by the real data.
124 static char *x11_fake_data = NULL;
125 static u_int x11_fake_data_len;
128 /* -- agent forwarding */
132 /* Name and directory of socket for authentication agent forwarding. */
133 static char *auth_sock_name = NULL;
134 static char *auth_sock_dir = NULL;
136 /* AF_UNSPEC or AF_INET or AF_INET6 */
137 static int IPv4or6 = AF_UNSPEC;
140 static void port_open_helper(Channel *c, char *rtype);
142 /* -- channel core */
145 channel_lookup(int id)
149 if (id < 0 || id > channels_alloc) {
150 log("channel_lookup: %d: bad id", id);
155 log("channel_lookup: %d: bad id: channel free", id);
162 * Register filedescriptors for a channel, used when allocating a channel or
163 * when the channel consumer/producer is ready, e.g. shell exec'd
167 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
168 int extusage, int nonblock)
170 /* Update the maximum file descriptor value. */
171 channel_max_fd = MAX(channel_max_fd, rfd);
172 channel_max_fd = MAX(channel_max_fd, wfd);
173 channel_max_fd = MAX(channel_max_fd, efd);
175 /* XXX set close-on-exec -markus */
179 c->sock = (rfd == wfd) ? rfd : -1;
181 c->extended_usage = extusage;
183 /* XXX ugly hack: nonblock is only set by the server */
184 if (nonblock && isatty(c->rfd)) {
185 debug("channel %d: rfd %d isatty", c->self, c->rfd);
187 if (!isatty(c->wfd)) {
188 error("channel %d: wfd %d is not a tty?",
195 /* enable nonblocking mode */
207 * Allocate a new channel object and set its type and socket. This will cause
208 * remote_name to be freed.
212 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
213 int window, int maxpack, int extusage, char *remote_name, int nonblock)
218 /* Do initial allocation if this is the first call. */
219 if (channels_alloc == 0) {
222 channels = xmalloc(channels_alloc * sizeof(Channel *));
223 for (i = 0; i < channels_alloc; i++)
225 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
227 /* Try to find a free slot where to put the new channel. */
228 for (found = -1, i = 0; i < channels_alloc; i++)
229 if (channels[i] == NULL) {
230 /* Found a free slot. */
235 /* There are no free slots. Take last+1 slot and expand the array. */
236 found = channels_alloc;
237 channels_alloc += 10;
238 debug2("channel: expanding %d", channels_alloc);
239 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
240 for (i = found; i < channels_alloc; i++)
243 /* Initialize and return new channel. */
244 c = channels[found] = xmalloc(sizeof(Channel));
245 memset(c, 0, sizeof(Channel));
246 buffer_init(&c->input);
247 buffer_init(&c->output);
248 buffer_init(&c->extended);
249 chan_init_iostates(c);
250 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
254 c->local_window = window;
255 c->local_window_max = window;
256 c->local_consumed = 0;
257 c->local_maxpacket = maxpack;
259 c->remote_name = remote_name;
260 c->remote_window = 0;
261 c->remote_maxpacket = 0;
266 c->detach_user = NULL;
267 c->input_filter = NULL;
268 debug("channel %d: new [%s]", found, remote_name);
273 channel_find_maxfd(void)
278 for (i = 0; i < channels_alloc; i++) {
281 max = MAX(max, c->rfd);
282 max = MAX(max, c->wfd);
283 max = MAX(max, c->efd);
290 channel_close_fd(int *fdp)
292 int ret = 0, fd = *fdp;
297 if (fd == channel_max_fd)
298 channel_max_fd = channel_find_maxfd();
303 /* Close all channel fd/socket. */
306 channel_close_fds(Channel *c)
308 debug3("channel_close_fds: channel %d: r %d w %d e %d",
309 c->self, c->rfd, c->wfd, c->efd);
311 channel_close_fd(&c->sock);
312 channel_close_fd(&c->rfd);
313 channel_close_fd(&c->wfd);
314 channel_close_fd(&c->efd);
317 /* Free the channel and close its fd/socket. */
320 channel_free(Channel *c)
325 for (n = 0, i = 0; i < channels_alloc; i++)
328 debug("channel_free: channel %d: %s, nchannels %d", c->self,
329 c->remote_name ? c->remote_name : "???", n);
331 s = channel_open_message();
332 debug3("channel_free: status: %s", s);
336 shutdown(c->sock, SHUT_RDWR);
337 channel_close_fds(c);
338 buffer_free(&c->input);
339 buffer_free(&c->output);
340 buffer_free(&c->extended);
341 if (c->remote_name) {
342 xfree(c->remote_name);
343 c->remote_name = NULL;
345 channels[c->self] = NULL;
350 channel_free_all(void)
354 for (i = 0; i < channels_alloc; i++)
355 if (channels[i] != NULL)
356 channel_free(channels[i]);
360 * Closes the sockets/fds of all channels. This is used to close extra file
361 * descriptors after a fork.
365 channel_close_all(void)
369 for (i = 0; i < channels_alloc; i++)
370 if (channels[i] != NULL)
371 channel_close_fds(channels[i]);
375 * Stop listening to channels.
379 channel_stop_listening(void)
384 for (i = 0; i < channels_alloc; i++) {
388 case SSH_CHANNEL_AUTH_SOCKET:
389 case SSH_CHANNEL_PORT_LISTENER:
390 case SSH_CHANNEL_RPORT_LISTENER:
391 case SSH_CHANNEL_X11_LISTENER:
392 channel_close_fd(&c->sock);
401 * Returns true if no channel has too much buffered data, and false if one or
402 * more channel is overfull.
406 channel_not_very_much_buffered_data(void)
411 for (i = 0; i < channels_alloc; i++) {
413 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
416 buffer_len(&c->input) > packet_get_maxsize()) {
417 debug("channel %d: big input buffer %d",
418 c->self, buffer_len(&c->input));
422 if (buffer_len(&c->output) > packet_get_maxsize()) {
423 debug("channel %d: big output buffer %d > %d",
424 c->self, buffer_len(&c->output),
425 packet_get_maxsize());
433 /* Returns true if any channel is still open. */
436 channel_still_open(void)
441 for (i = 0; i < channels_alloc; i++) {
446 case SSH_CHANNEL_X11_LISTENER:
447 case SSH_CHANNEL_PORT_LISTENER:
448 case SSH_CHANNEL_RPORT_LISTENER:
449 case SSH_CHANNEL_CLOSED:
450 case SSH_CHANNEL_AUTH_SOCKET:
451 case SSH_CHANNEL_DYNAMIC:
452 case SSH_CHANNEL_CONNECTING:
453 case SSH_CHANNEL_ZOMBIE:
455 case SSH_CHANNEL_LARVAL:
457 fatal("cannot happen: SSH_CHANNEL_LARVAL");
459 case SSH_CHANNEL_OPENING:
460 case SSH_CHANNEL_OPEN:
461 case SSH_CHANNEL_X11_OPEN:
463 case SSH_CHANNEL_INPUT_DRAINING:
464 case SSH_CHANNEL_OUTPUT_DRAINING:
466 fatal("cannot happen: OUT_DRAIN");
469 fatal("channel_still_open: bad channel type %d", c->type);
476 /* Returns the id of an open channel suitable for keepaliving */
479 channel_find_open(void)
484 for (i = 0; i < channels_alloc; i++) {
489 case SSH_CHANNEL_CLOSED:
490 case SSH_CHANNEL_DYNAMIC:
491 case SSH_CHANNEL_X11_LISTENER:
492 case SSH_CHANNEL_PORT_LISTENER:
493 case SSH_CHANNEL_RPORT_LISTENER:
494 case SSH_CHANNEL_OPENING:
495 case SSH_CHANNEL_CONNECTING:
496 case SSH_CHANNEL_ZOMBIE:
498 case SSH_CHANNEL_LARVAL:
499 case SSH_CHANNEL_AUTH_SOCKET:
500 case SSH_CHANNEL_OPEN:
501 case SSH_CHANNEL_X11_OPEN:
503 case SSH_CHANNEL_INPUT_DRAINING:
504 case SSH_CHANNEL_OUTPUT_DRAINING:
506 fatal("cannot happen: OUT_DRAIN");
509 fatal("channel_find_open: bad channel type %d", c->type);
518 * Returns a message describing the currently open forwarded connections,
519 * suitable for sending to the client. The message contains crlf pairs for
524 channel_open_message(void)
531 buffer_init(&buffer);
532 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
533 buffer_append(&buffer, buf, strlen(buf));
534 for (i = 0; i < channels_alloc; i++) {
539 case SSH_CHANNEL_X11_LISTENER:
540 case SSH_CHANNEL_PORT_LISTENER:
541 case SSH_CHANNEL_RPORT_LISTENER:
542 case SSH_CHANNEL_CLOSED:
543 case SSH_CHANNEL_AUTH_SOCKET:
544 case SSH_CHANNEL_ZOMBIE:
546 case SSH_CHANNEL_LARVAL:
547 case SSH_CHANNEL_OPENING:
548 case SSH_CHANNEL_CONNECTING:
549 case SSH_CHANNEL_DYNAMIC:
550 case SSH_CHANNEL_OPEN:
551 case SSH_CHANNEL_X11_OPEN:
552 case SSH_CHANNEL_INPUT_DRAINING:
553 case SSH_CHANNEL_OUTPUT_DRAINING:
554 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
555 c->self, c->remote_name,
556 c->type, c->remote_id,
557 c->istate, buffer_len(&c->input),
558 c->ostate, buffer_len(&c->output),
560 buffer_append(&buffer, buf, strlen(buf));
563 fatal("channel_open_message: bad channel type %d", c->type);
567 buffer_append(&buffer, "\0", 1);
568 cp = xstrdup(buffer_ptr(&buffer));
569 buffer_free(&buffer);
574 channel_send_open(int id)
576 Channel *c = channel_lookup(id);
578 log("channel_send_open: %d: bad id", id);
581 debug("send channel open %d", id);
582 packet_start(SSH2_MSG_CHANNEL_OPEN);
583 packet_put_cstring(c->ctype);
584 packet_put_int(c->self);
585 packet_put_int(c->local_window);
586 packet_put_int(c->local_maxpacket);
591 channel_request(int id, char *service, int wantconfirm)
593 channel_request_start(id, service, wantconfirm);
595 debug("channel request %d: %s", id, service) ;
598 channel_request_start(int id, char *service, int wantconfirm)
600 Channel *c = channel_lookup(id);
602 log("channel_request: %d: bad id", id);
605 packet_start(SSH2_MSG_CHANNEL_REQUEST);
606 packet_put_int(c->remote_id);
607 packet_put_cstring(service);
608 packet_put_char(wantconfirm);
611 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
613 Channel *c = channel_lookup(id);
615 log("channel_register_callback: %d: bad id", id);
623 channel_register_cleanup(int id, channel_callback_fn *fn)
625 Channel *c = channel_lookup(id);
627 log("channel_register_cleanup: %d: bad id", id);
633 channel_cancel_cleanup(int id)
635 Channel *c = channel_lookup(id);
637 log("channel_cancel_cleanup: %d: bad id", id);
640 c->detach_user = NULL;
643 channel_register_filter(int id, channel_filter_fn *fn)
645 Channel *c = channel_lookup(id);
647 log("channel_register_filter: %d: bad id", id);
650 c->input_filter = fn;
654 channel_set_fds(int id, int rfd, int wfd, int efd,
655 int extusage, int nonblock)
657 Channel *c = channel_lookup(id);
658 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
659 fatal("channel_activate for non-larval channel %d.", id);
660 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
661 c->type = SSH_CHANNEL_OPEN;
662 /* XXX window size? */
663 c->local_window = c->local_window_max = c->local_maxpacket * 2;
664 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
665 packet_put_int(c->remote_id);
666 packet_put_int(c->local_window);
671 * 'channel_pre*' are called just before select() to add any bits relevant to
672 * channels in the select bitmasks.
675 * 'channel_post*': perform any appropriate operations for channels which
676 * have events pending.
678 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
679 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
680 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
683 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
685 FD_SET(c->sock, readset);
689 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
691 debug3("channel %d: waiting for connection", c->self);
692 FD_SET(c->sock, writeset);
696 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
698 if (buffer_len(&c->input) < packet_get_maxsize())
699 FD_SET(c->sock, readset);
700 if (buffer_len(&c->output) > 0)
701 FD_SET(c->sock, writeset);
705 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
707 /* test whether sockets are 'alive' for read/write */
708 if (c->istate == CHAN_INPUT_OPEN)
709 if (buffer_len(&c->input) < packet_get_maxsize())
710 FD_SET(c->sock, readset);
711 if (c->ostate == CHAN_OUTPUT_OPEN ||
712 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
713 if (buffer_len(&c->output) > 0) {
714 FD_SET(c->sock, writeset);
715 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
722 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
724 if (c->istate == CHAN_INPUT_OPEN &&
725 c->remote_window > 0 &&
726 buffer_len(&c->input) < c->remote_window)
727 FD_SET(c->rfd, readset);
728 if (c->ostate == CHAN_OUTPUT_OPEN ||
729 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
730 if (buffer_len(&c->output) > 0) {
731 FD_SET(c->wfd, writeset);
732 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
736 /** XXX check close conditions, too */
738 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
739 buffer_len(&c->extended) > 0)
740 FD_SET(c->efd, writeset);
741 else if (c->extended_usage == CHAN_EXTENDED_READ &&
742 buffer_len(&c->extended) < c->remote_window)
743 FD_SET(c->efd, readset);
748 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
750 if (buffer_len(&c->input) == 0) {
751 packet_start(SSH_MSG_CHANNEL_CLOSE);
752 packet_put_int(c->remote_id);
754 c->type = SSH_CHANNEL_CLOSED;
755 debug("channel %d: closing after input drain.", c->self);
760 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
762 if (buffer_len(&c->output) == 0)
765 FD_SET(c->sock, writeset);
769 * This is a special state for X11 authentication spoofing. An opened X11
770 * connection (when authentication spoofing is being done) remains in this
771 * state until the first packet has been completely read. The authentication
772 * data in that packet is then substituted by the real data if it matches the
773 * fake data, and the channel is put into normal mode.
774 * XXX All this happens at the client side.
775 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
778 x11_open_helper(Buffer *b)
781 u_int proto_len, data_len;
783 /* Check if the fixed size part of the packet is in buffer. */
784 if (buffer_len(b) < 12)
787 /* Parse the lengths of variable-length fields. */
788 ucp = (u_char *) buffer_ptr(b);
789 if (ucp[0] == 0x42) { /* Byte order MSB first. */
790 proto_len = 256 * ucp[6] + ucp[7];
791 data_len = 256 * ucp[8] + ucp[9];
792 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
793 proto_len = ucp[6] + 256 * ucp[7];
794 data_len = ucp[8] + 256 * ucp[9];
796 debug("Initial X11 packet contains bad byte order byte: 0x%x",
801 /* Check if the whole packet is in buffer. */
803 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
806 /* Check if authentication protocol matches. */
807 if (proto_len != strlen(x11_saved_proto) ||
808 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
809 debug("X11 connection uses different authentication protocol.");
812 /* Check if authentication data matches our fake data. */
813 if (data_len != x11_fake_data_len ||
814 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
815 x11_fake_data, x11_fake_data_len) != 0) {
816 debug("X11 auth data does not match fake data.");
819 /* Check fake data length */
820 if (x11_fake_data_len != x11_saved_data_len) {
821 error("X11 fake_data_len %d != saved_data_len %d",
822 x11_fake_data_len, x11_saved_data_len);
826 * Received authentication protocol and data match
827 * our fake data. Substitute the fake data with real
830 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
831 x11_saved_data, x11_saved_data_len);
836 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
838 int ret = x11_open_helper(&c->output);
840 /* Start normal processing for the channel. */
841 c->type = SSH_CHANNEL_OPEN;
842 channel_pre_open_13(c, readset, writeset);
843 } else if (ret == -1) {
845 * We have received an X11 connection that has bad
846 * authentication information.
848 log("X11 connection rejected because of wrong authentication.");
849 buffer_clear(&c->input);
850 buffer_clear(&c->output);
851 channel_close_fd(&c->sock);
853 c->type = SSH_CHANNEL_CLOSED;
854 packet_start(SSH_MSG_CHANNEL_CLOSE);
855 packet_put_int(c->remote_id);
861 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
863 int ret = x11_open_helper(&c->output);
865 /* c->force_drain = 1; */
868 c->type = SSH_CHANNEL_OPEN;
870 channel_pre_open_20(c, readset, writeset);
872 channel_pre_open_15(c, readset, writeset);
873 } else if (ret == -1) {
874 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
875 chan_read_failed(c); /** force close? */
876 chan_write_failed(c);
877 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
881 /* try to decode a socks4 header */
883 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
886 int len, have, i, found;
892 struct in_addr dest_addr;
895 debug2("channel %d: decode socks4", c->self);
897 have = buffer_len(&c->input);
898 len = sizeof(s4_req);
901 p = buffer_ptr(&c->input);
902 for (found = 0, i = len; i < have; i++) {
908 /* the peer is probably sending garbage */
909 debug("channel %d: decode socks4: too long",
916 buffer_get(&c->input, (char *)&s4_req.version, 1);
917 buffer_get(&c->input, (char *)&s4_req.command, 1);
918 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
919 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
920 have = buffer_len(&c->input);
921 p = buffer_ptr(&c->input);
923 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
925 fatal("channel %d: decode socks4: len %d > have %d",
927 strlcpy(username, p, sizeof(username));
928 buffer_consume(&c->input, len);
929 buffer_consume(&c->input, 1); /* trailing '\0' */
931 host = inet_ntoa(s4_req.dest_addr);
932 strlcpy(c->path, host, sizeof(c->path));
933 c->host_port = ntohs(s4_req.dest_port);
935 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
936 c->self, host, c->host_port, s4_req.command);
938 if (s4_req.command != 1) {
939 debug("channel %d: cannot handle: socks4 cn %d",
940 c->self, s4_req.command);
943 s4_rsp.version = 0; /* vn: 0 for reply */
944 s4_rsp.command = 90; /* cd: req granted */
945 s4_rsp.dest_port = 0; /* ignored */
946 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
947 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
951 /* dynamic port forwarding */
953 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
958 have = buffer_len(&c->input);
960 debug2("channel %d: pre_dynamic: have %d", c->self, have);
961 /* buffer_dump(&c->input); */
962 /* check if the fixed size part of the packet is in buffer. */
965 FD_SET(c->sock, readset);
968 /* try to guess the protocol */
969 p = buffer_ptr(&c->input);
972 ret = channel_decode_socks4(c, readset, writeset);
980 } else if (ret == 0) {
981 debug2("channel %d: pre_dynamic: need more", c->self);
983 FD_SET(c->sock, readset);
985 /* switch to the next state */
986 c->type = SSH_CHANNEL_OPENING;
987 port_open_helper(c, "direct-tcpip");
991 /* This is our fake X11 server socket. */
993 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
996 struct sockaddr addr;
999 char buf[16384], *remote_ipaddr;
1002 if (FD_ISSET(c->sock, readset)) {
1003 debug("X11 connection requested.");
1004 addrlen = sizeof(addr);
1005 newsock = accept(c->sock, &addr, &addrlen);
1007 error("accept: %.100s", strerror(errno));
1010 if (setsockopt(newsock, IPPROTO_TCP, TCP_NODELAY, &on,
1012 error("setsockopt TCP_NODELAY: %.100s",
1014 remote_ipaddr = get_peer_ipaddr(newsock);
1015 remote_port = get_peer_port(newsock);
1016 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1017 remote_ipaddr, remote_port);
1019 nc = channel_new("accepted x11 socket",
1020 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1021 c->local_window_max, c->local_maxpacket,
1022 0, xstrdup(buf), 1);
1025 xfree(remote_ipaddr);
1029 packet_start(SSH2_MSG_CHANNEL_OPEN);
1030 packet_put_cstring("x11");
1031 packet_put_int(nc->self);
1032 packet_put_int(c->local_window_max);
1033 packet_put_int(c->local_maxpacket);
1034 /* originator ipaddr and port */
1035 packet_put_cstring(remote_ipaddr);
1036 if (datafellows & SSH_BUG_X11FWD) {
1037 debug("ssh2 x11 bug compat mode");
1039 packet_put_int(remote_port);
1043 packet_start(SSH_SMSG_X11_OPEN);
1044 packet_put_int(nc->self);
1045 if (packet_get_protocol_flags() &
1046 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1047 packet_put_cstring(buf);
1050 xfree(remote_ipaddr);
1055 port_open_helper(Channel *c, char *rtype)
1059 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1060 u_short remote_port = get_peer_port(c->sock);
1062 direct = (strcmp(rtype, "direct-tcpip") == 0);
1064 snprintf(buf, sizeof buf,
1065 "%s: listening port %d for %.100s port %d, "
1066 "connect from %.200s port %d",
1067 rtype, c->listening_port, c->path, c->host_port,
1068 remote_ipaddr, remote_port);
1070 xfree(c->remote_name);
1071 c->remote_name = xstrdup(buf);
1074 packet_start(SSH2_MSG_CHANNEL_OPEN);
1075 packet_put_cstring(rtype);
1076 packet_put_int(c->self);
1077 packet_put_int(c->local_window_max);
1078 packet_put_int(c->local_maxpacket);
1080 /* target host, port */
1081 packet_put_cstring(c->path);
1082 packet_put_int(c->host_port);
1084 /* listen address, port */
1085 packet_put_cstring(c->path);
1086 packet_put_int(c->listening_port);
1088 /* originator host and port */
1089 packet_put_cstring(remote_ipaddr);
1090 packet_put_int(remote_port);
1093 packet_start(SSH_MSG_PORT_OPEN);
1094 packet_put_int(c->self);
1095 packet_put_cstring(c->path);
1096 packet_put_int(c->host_port);
1097 if (packet_get_protocol_flags() &
1098 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1099 packet_put_cstring(c->remote_name);
1102 xfree(remote_ipaddr);
1106 * This socket is listening for connections to a forwarded TCP/IP port.
1109 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1112 struct sockaddr addr;
1113 int newsock, nextstate;
1117 if (FD_ISSET(c->sock, readset)) {
1118 debug("Connection to port %d forwarding "
1119 "to %.100s port %d requested.",
1120 c->listening_port, c->path, c->host_port);
1122 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1123 nextstate = SSH_CHANNEL_OPENING;
1124 rtype = "forwarded-tcpip";
1126 if (c->host_port == 0) {
1127 nextstate = SSH_CHANNEL_DYNAMIC;
1128 rtype = "dynamic-tcpip";
1130 nextstate = SSH_CHANNEL_OPENING;
1131 rtype = "direct-tcpip";
1135 addrlen = sizeof(addr);
1136 newsock = accept(c->sock, &addr, &addrlen);
1138 error("accept: %.100s", strerror(errno));
1141 nc = channel_new(rtype,
1142 nextstate, newsock, newsock, -1,
1143 c->local_window_max, c->local_maxpacket,
1144 0, xstrdup(rtype), 1);
1146 error("channel_post_port_listener: no new channel:");
1150 nc->listening_port = c->listening_port;
1151 nc->host_port = c->host_port;
1152 strlcpy(nc->path, c->path, sizeof(nc->path));
1154 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1156 * do not call the channel_post handler until
1157 * this flag has been reset by a pre-handler.
1158 * otherwise the FD_ISSET calls might overflow
1162 port_open_helper(nc, rtype);
1168 * This is the authentication agent socket listening for connections from
1172 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1177 struct sockaddr addr;
1180 if (FD_ISSET(c->sock, readset)) {
1181 addrlen = sizeof(addr);
1182 newsock = accept(c->sock, &addr, &addrlen);
1184 error("accept from auth socket: %.100s", strerror(errno));
1187 name = xstrdup("accepted auth socket");
1188 nc = channel_new("accepted auth socket",
1189 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1190 c->local_window_max, c->local_maxpacket,
1193 error("channel_post_auth_listener: channel_new failed");
1198 packet_start(SSH2_MSG_CHANNEL_OPEN);
1199 packet_put_cstring("auth-agent@openssh.com");
1200 packet_put_int(nc->self);
1201 packet_put_int(c->local_window_max);
1202 packet_put_int(c->local_maxpacket);
1204 packet_start(SSH_SMSG_AGENT_OPEN);
1205 packet_put_int(nc->self);
1212 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1215 socklen_t sz = sizeof(err);
1217 if (FD_ISSET(c->sock, writeset)) {
1218 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1221 error("getsockopt SO_ERROR failed");
1224 debug("channel %d: connected", c->self);
1225 c->type = SSH_CHANNEL_OPEN;
1227 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1228 packet_put_int(c->remote_id);
1229 packet_put_int(c->self);
1230 packet_put_int(c->local_window);
1231 packet_put_int(c->local_maxpacket);
1233 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1234 packet_put_int(c->remote_id);
1235 packet_put_int(c->self);
1238 debug("channel %d: not connected: %s",
1239 c->self, strerror(err));
1241 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1242 packet_put_int(c->remote_id);
1243 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1244 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1245 packet_put_cstring(strerror(err));
1246 packet_put_cstring("");
1249 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1250 packet_put_int(c->remote_id);
1259 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1265 FD_ISSET(c->rfd, readset)) {
1266 len = read(c->rfd, buf, sizeof(buf));
1267 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1270 debug("channel %d: read<=0 rfd %d len %d",
1271 c->self, c->rfd, len);
1272 if (c->type != SSH_CHANNEL_OPEN) {
1273 debug("channel %d: not open", c->self);
1276 } else if (compat13) {
1277 buffer_consume(&c->output, buffer_len(&c->output));
1278 c->type = SSH_CHANNEL_INPUT_DRAINING;
1279 debug("channel %d: input draining.", c->self);
1281 chan_read_failed(c);
1285 if (c->input_filter != NULL) {
1286 if (c->input_filter(c, buf, len) == -1) {
1287 debug("channel %d: filter stops", c->self);
1288 chan_read_failed(c);
1291 buffer_append(&c->input, buf, len);
1297 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1304 /* Send buffered output data to the socket. */
1306 FD_ISSET(c->wfd, writeset) &&
1307 buffer_len(&c->output) > 0) {
1308 data = buffer_ptr(&c->output);
1309 dlen = buffer_len(&c->output);
1310 len = write(c->wfd, data, dlen);
1311 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1314 if (c->type != SSH_CHANNEL_OPEN) {
1315 debug("channel %d: not open", c->self);
1318 } else if (compat13) {
1319 buffer_consume(&c->output, buffer_len(&c->output));
1320 debug("channel %d: input draining.", c->self);
1321 c->type = SSH_CHANNEL_INPUT_DRAINING;
1323 chan_write_failed(c);
1327 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1328 if (tcgetattr(c->wfd, &tio) == 0 &&
1329 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1331 * Simulate echo to reduce the impact of
1332 * traffic analysis. We need to match the
1333 * size of a SSH2_MSG_CHANNEL_DATA message
1334 * (4 byte channel id + data)
1336 packet_send_ignore(4 + len);
1340 buffer_consume(&c->output, len);
1341 if (compat20 && len > 0) {
1342 c->local_consumed += len;
1348 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1353 /** XXX handle drain efd, too */
1355 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1356 FD_ISSET(c->efd, writeset) &&
1357 buffer_len(&c->extended) > 0) {
1358 len = write(c->efd, buffer_ptr(&c->extended),
1359 buffer_len(&c->extended));
1360 debug2("channel %d: written %d to efd %d",
1361 c->self, len, c->efd);
1362 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1365 debug2("channel %d: closing write-efd %d",
1367 channel_close_fd(&c->efd);
1369 buffer_consume(&c->extended, len);
1370 c->local_consumed += len;
1372 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1373 FD_ISSET(c->efd, readset)) {
1374 len = read(c->efd, buf, sizeof(buf));
1375 debug2("channel %d: read %d from efd %d",
1376 c->self, len, c->efd);
1377 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1380 debug2("channel %d: closing read-efd %d",
1382 channel_close_fd(&c->efd);
1384 buffer_append(&c->extended, buf, len);
1391 channel_check_window(Channel *c)
1393 if (c->type == SSH_CHANNEL_OPEN &&
1394 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1395 c->local_window < c->local_window_max/2 &&
1396 c->local_consumed > 0) {
1397 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1398 packet_put_int(c->remote_id);
1399 packet_put_int(c->local_consumed);
1401 debug2("channel %d: window %d sent adjust %d",
1402 c->self, c->local_window,
1404 c->local_window += c->local_consumed;
1405 c->local_consumed = 0;
1411 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1415 channel_handle_rfd(c, readset, writeset);
1416 channel_handle_wfd(c, readset, writeset);
1420 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1424 channel_handle_rfd(c, readset, writeset);
1425 channel_handle_wfd(c, readset, writeset);
1426 channel_handle_efd(c, readset, writeset);
1428 channel_check_window(c);
1432 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1435 /* Send buffered output data to the socket. */
1436 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1437 len = write(c->sock, buffer_ptr(&c->output),
1438 buffer_len(&c->output));
1440 buffer_consume(&c->output, buffer_len(&c->output));
1442 buffer_consume(&c->output, len);
1447 channel_handler_init_20(void)
1449 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1450 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1451 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1452 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1453 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1454 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1455 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1456 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1458 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1459 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1460 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1461 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1462 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1463 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1464 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1468 channel_handler_init_13(void)
1470 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1471 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1472 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1473 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1474 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1475 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1476 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1477 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1478 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1480 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1481 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1482 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1483 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1484 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1485 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1486 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1490 channel_handler_init_15(void)
1492 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1493 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1494 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1495 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1496 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1497 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1498 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1500 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1501 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1502 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1503 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1504 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1505 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1509 channel_handler_init(void)
1512 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1513 channel_pre[i] = NULL;
1514 channel_post[i] = NULL;
1517 channel_handler_init_20();
1519 channel_handler_init_13();
1521 channel_handler_init_15();
1524 /* gc dead channels */
1526 channel_garbage_collect(Channel *c)
1530 if (c->detach_user != NULL) {
1531 if (!chan_is_dead(c, 0))
1533 debug("channel %d: gc: notify user", c->self);
1534 c->detach_user(c->self, NULL);
1535 /* if we still have a callback */
1536 if (c->detach_user != NULL)
1538 debug("channel %d: gc: user detached", c->self);
1540 if (!chan_is_dead(c, 1))
1542 debug("channel %d: garbage collecting", c->self);
1547 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1549 static int did_init = 0;
1554 channel_handler_init();
1557 for (i = 0; i < channels_alloc; i++) {
1561 if (ftab[c->type] != NULL)
1562 (*ftab[c->type])(c, readset, writeset);
1563 channel_garbage_collect(c);
1568 * Allocate/update select bitmasks and add any bits relevant to channels in
1572 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1573 int *nallocp, int rekeying)
1578 n = MAX(*maxfdp, channel_max_fd);
1580 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1581 /* perhaps check sz < nalloc/2 and shrink? */
1582 if (*readsetp == NULL || sz > *nallocp) {
1583 *readsetp = xrealloc(*readsetp, sz);
1584 *writesetp = xrealloc(*writesetp, sz);
1588 memset(*readsetp, 0, sz);
1589 memset(*writesetp, 0, sz);
1592 channel_handler(channel_pre, *readsetp, *writesetp);
1596 * After select, perform any appropriate operations for channels which have
1600 channel_after_select(fd_set * readset, fd_set * writeset)
1602 channel_handler(channel_post, readset, writeset);
1606 /* If there is data to send to the connection, enqueue some of it now. */
1609 channel_output_poll(void)
1614 for (i = 0; i < channels_alloc; i++) {
1620 * We are only interested in channels that can have buffered
1624 if (c->type != SSH_CHANNEL_OPEN &&
1625 c->type != SSH_CHANNEL_INPUT_DRAINING)
1628 if (c->type != SSH_CHANNEL_OPEN)
1632 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1633 /* XXX is this true? */
1634 debug3("channel %d: will not send data after close", c->self);
1638 /* Get the amount of buffered data for this channel. */
1639 if ((c->istate == CHAN_INPUT_OPEN ||
1640 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1641 (len = buffer_len(&c->input)) > 0) {
1643 * Send some data for the other side over the secure
1647 if (len > c->remote_window)
1648 len = c->remote_window;
1649 if (len > c->remote_maxpacket)
1650 len = c->remote_maxpacket;
1652 if (packet_is_interactive()) {
1656 /* Keep the packets at reasonable size. */
1657 if (len > packet_get_maxsize()/2)
1658 len = packet_get_maxsize()/2;
1662 packet_start(compat20 ?
1663 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1664 packet_put_int(c->remote_id);
1665 packet_put_string(buffer_ptr(&c->input), len);
1667 buffer_consume(&c->input, len);
1668 c->remote_window -= len;
1670 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1672 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1674 * input-buffer is empty and read-socket shutdown:
1675 * tell peer, that we will not send more data: send IEOF
1679 /* Send extended data, i.e. stderr */
1681 c->remote_window > 0 &&
1682 (len = buffer_len(&c->extended)) > 0 &&
1683 c->extended_usage == CHAN_EXTENDED_READ) {
1684 debug2("channel %d: rwin %d elen %d euse %d",
1685 c->self, c->remote_window, buffer_len(&c->extended),
1687 if (len > c->remote_window)
1688 len = c->remote_window;
1689 if (len > c->remote_maxpacket)
1690 len = c->remote_maxpacket;
1691 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1692 packet_put_int(c->remote_id);
1693 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1694 packet_put_string(buffer_ptr(&c->extended), len);
1696 buffer_consume(&c->extended, len);
1697 c->remote_window -= len;
1698 debug2("channel %d: sent ext data %d", c->self, len);
1704 /* -- protocol input */
1707 channel_input_data(int type, int plen, void *ctxt)
1714 /* Get the channel number and verify it. */
1715 id = packet_get_int();
1716 c = channel_lookup(id);
1718 packet_disconnect("Received data for nonexistent channel %d.", id);
1720 /* Ignore any data for non-open channels (might happen on close) */
1721 if (c->type != SSH_CHANNEL_OPEN &&
1722 c->type != SSH_CHANNEL_X11_OPEN)
1725 /* same for protocol 1.5 if output end is no longer open */
1726 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1730 data = packet_get_string(&data_len);
1734 if (data_len > c->local_maxpacket) {
1735 log("channel %d: rcvd big packet %d, maxpack %d",
1736 c->self, data_len, c->local_maxpacket);
1738 if (data_len > c->local_window) {
1739 log("channel %d: rcvd too much data %d, win %d",
1740 c->self, data_len, c->local_window);
1744 c->local_window -= data_len;
1746 packet_integrity_check(plen, 4 + 4 + data_len, type);
1748 buffer_append(&c->output, data, data_len);
1753 channel_input_extended_data(int type, int plen, void *ctxt)
1761 /* Get the channel number and verify it. */
1762 id = packet_get_int();
1763 c = channel_lookup(id);
1766 packet_disconnect("Received extended_data for bad channel %d.", id);
1767 if (c->type != SSH_CHANNEL_OPEN) {
1768 log("channel %d: ext data for non open", id);
1771 tcode = packet_get_int();
1773 c->extended_usage != CHAN_EXTENDED_WRITE ||
1774 tcode != SSH2_EXTENDED_DATA_STDERR) {
1775 log("channel %d: bad ext data", c->self);
1778 data = packet_get_string(&data_len);
1780 if (data_len > c->local_window) {
1781 log("channel %d: rcvd too much extended_data %d, win %d",
1782 c->self, data_len, c->local_window);
1786 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1787 c->local_window -= data_len;
1788 buffer_append(&c->extended, data, data_len);
1793 channel_input_ieof(int type, int plen, void *ctxt)
1798 packet_integrity_check(plen, 4, type);
1800 id = packet_get_int();
1801 c = channel_lookup(id);
1803 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1806 /* XXX force input close */
1807 if (c->force_drain) {
1808 debug("channel %d: FORCE input drain", c->self);
1809 c->istate = CHAN_INPUT_WAIT_DRAIN;
1815 channel_input_close(int type, int plen, void *ctxt)
1820 packet_integrity_check(plen, 4, type);
1822 id = packet_get_int();
1823 c = channel_lookup(id);
1825 packet_disconnect("Received close for nonexistent channel %d.", id);
1828 * Send a confirmation that we have closed the channel and no more
1829 * data is coming for it.
1831 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1832 packet_put_int(c->remote_id);
1836 * If the channel is in closed state, we have sent a close request,
1837 * and the other side will eventually respond with a confirmation.
1838 * Thus, we cannot free the channel here, because then there would be
1839 * no-one to receive the confirmation. The channel gets freed when
1840 * the confirmation arrives.
1842 if (c->type != SSH_CHANNEL_CLOSED) {
1844 * Not a closed channel - mark it as draining, which will
1845 * cause it to be freed later.
1847 buffer_consume(&c->input, buffer_len(&c->input));
1848 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1852 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1854 channel_input_oclose(int type, int plen, void *ctxt)
1856 int id = packet_get_int();
1857 Channel *c = channel_lookup(id);
1858 packet_integrity_check(plen, 4, type);
1860 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1861 chan_rcvd_oclose(c);
1865 channel_input_close_confirmation(int type, int plen, void *ctxt)
1867 int id = packet_get_int();
1868 Channel *c = channel_lookup(id);
1872 packet_disconnect("Received close confirmation for "
1873 "out-of-range channel %d.", id);
1874 if (c->type != SSH_CHANNEL_CLOSED)
1875 packet_disconnect("Received close confirmation for "
1876 "non-closed channel %d (type %d).", id, c->type);
1881 channel_input_open_confirmation(int type, int plen, void *ctxt)
1887 packet_integrity_check(plen, 4 + 4, type);
1889 id = packet_get_int();
1890 c = channel_lookup(id);
1892 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1893 packet_disconnect("Received open confirmation for "
1894 "non-opening channel %d.", id);
1895 remote_id = packet_get_int();
1896 /* Record the remote channel number and mark that the channel is now open. */
1897 c->remote_id = remote_id;
1898 c->type = SSH_CHANNEL_OPEN;
1901 c->remote_window = packet_get_int();
1902 c->remote_maxpacket = packet_get_int();
1904 if (c->cb_fn != NULL && c->cb_event == type) {
1905 debug2("callback start");
1906 c->cb_fn(c->self, c->cb_arg);
1907 debug2("callback done");
1909 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1910 c->remote_window, c->remote_maxpacket);
1915 reason2txt(int reason)
1918 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1919 return "administratively prohibited";
1920 case SSH2_OPEN_CONNECT_FAILED:
1921 return "connect failed";
1922 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1923 return "unknown channel type";
1924 case SSH2_OPEN_RESOURCE_SHORTAGE:
1925 return "resource shortage";
1927 return "unknown reason";
1931 channel_input_open_failure(int type, int plen, void *ctxt)
1934 char *msg = NULL, *lang = NULL;
1938 packet_integrity_check(plen, 4, type);
1940 id = packet_get_int();
1941 c = channel_lookup(id);
1943 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1944 packet_disconnect("Received open failure for "
1945 "non-opening channel %d.", id);
1947 reason = packet_get_int();
1948 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1949 msg = packet_get_string(NULL);
1950 lang = packet_get_string(NULL);
1953 log("channel %d: open failed: %s%s%s", id,
1954 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1960 /* Free the channel. This will also close the socket. */
1965 channel_input_channel_request(int type, int plen, void *ctxt)
1970 id = packet_get_int();
1971 c = channel_lookup(id);
1974 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1975 packet_disconnect("Received request for "
1976 "non-open channel %d.", id);
1977 if (c->cb_fn != NULL && c->cb_event == type) {
1978 debug2("callback start");
1979 c->cb_fn(c->self, c->cb_arg);
1980 debug2("callback done");
1982 char *service = packet_get_string(NULL);
1983 debug("channel %d: rcvd request for %s", c->self, service);
1984 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1990 channel_input_window_adjust(int type, int plen, void *ctxt)
1998 /* Get the channel number and verify it. */
1999 id = packet_get_int();
2000 c = channel_lookup(id);
2002 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2003 log("Received window adjust for "
2004 "non-open channel %d.", id);
2007 adjust = packet_get_int();
2009 debug2("channel %d: rcvd adjust %d", id, adjust);
2010 c->remote_window += adjust;
2014 channel_input_port_open(int type, int plen, void *ctxt)
2018 char *host, *originator_string;
2019 int remote_id, sock = -1;
2021 remote_id = packet_get_int();
2022 host = packet_get_string(NULL);
2023 host_port = packet_get_int();
2025 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2026 originator_string = packet_get_string(NULL);
2028 originator_string = xstrdup("unknown (remote did not supply name)");
2031 sock = channel_connect_to(host, host_port);
2033 c = channel_new("connected socket",
2034 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2035 originator_string, 1);
2037 error("channel_input_port_open: channel_new failed");
2040 c->remote_id = remote_id;
2044 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2045 packet_put_int(remote_id);
2052 /* -- tcp forwarding */
2055 channel_set_af(int af)
2061 * Initiate forwarding of connections to local port "port" through the secure
2062 * channel to host:port from remote side.
2065 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2066 u_short port_to_connect, int gateway_ports)
2068 return channel_request_forwarding(
2070 host_to_connect, port_to_connect,
2071 gateway_ports, /*remote_fwd*/ 0);
2075 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2076 * (SSH_CHANNEL_RPORT_LISTENER).
2079 channel_request_forwarding(
2080 const char *listen_address, u_short listen_port,
2081 const char *host_to_connect, u_short port_to_connect,
2082 int gateway_ports, int remote_fwd)
2085 int success, sock, on = 1, type;
2086 struct addrinfo hints, *ai, *aitop;
2087 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2089 struct linger linger;
2094 host = listen_address;
2095 type = SSH_CHANNEL_RPORT_LISTENER;
2097 host = host_to_connect;
2098 type = SSH_CHANNEL_PORT_LISTENER;
2101 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2102 error("Forward host name too long.");
2106 /* XXX listen_address is currently ignored */
2108 * getaddrinfo returns a loopback address if the hostname is
2109 * set to NULL and hints.ai_flags is not AI_PASSIVE
2111 memset(&hints, 0, sizeof(hints));
2112 hints.ai_family = IPv4or6;
2113 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2114 hints.ai_socktype = SOCK_STREAM;
2115 snprintf(strport, sizeof strport, "%d", listen_port);
2116 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2117 packet_disconnect("getaddrinfo: fatal error");
2119 for (ai = aitop; ai; ai = ai->ai_next) {
2120 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2122 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2123 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2124 error("channel_request_forwarding: getnameinfo failed");
2127 /* Create a port to listen for the host. */
2128 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2130 /* this is no error since kernel may not support ipv6 */
2131 verbose("socket: %.100s", strerror(errno));
2135 * Set socket options. We would like the socket to disappear
2136 * as soon as it has been closed for whatever reason.
2138 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2140 linger.l_linger = 5;
2141 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2142 debug("Local forwarding listening on %s port %s.", ntop, strport);
2144 /* Bind the socket to the address. */
2145 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2146 /* address can be in use ipv6 address is already bound */
2148 error("bind: %.100s", strerror(errno));
2150 verbose("bind: %.100s", strerror(errno));
2155 /* Start listening for connections on the socket. */
2156 if (listen(sock, 5) < 0) {
2157 error("listen: %.100s", strerror(errno));
2161 /* Allocate a channel number for the socket. */
2162 c = channel_new("port listener", type, sock, sock, -1,
2163 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2164 0, xstrdup("port listener"), 1);
2166 error("channel_request_forwarding: channel_new failed");
2170 strlcpy(c->path, host, sizeof(c->path));
2171 c->host_port = port_to_connect;
2172 c->listening_port = listen_port;
2176 error("channel_request_forwarding: cannot listen to port: %d",
2178 freeaddrinfo(aitop);
2183 * Initiate forwarding of connections to port "port" on remote host through
2184 * the secure channel to host:port from local side.
2188 channel_request_remote_forwarding(u_short listen_port,
2189 const char *host_to_connect, u_short port_to_connect)
2191 int payload_len, type, success = 0;
2193 /* Record locally that connection to this host/port is permitted. */
2194 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2195 fatal("channel_request_remote_forwarding: too many forwards");
2197 /* Send the forward request to the remote side. */
2199 const char *address_to_bind = "0.0.0.0";
2200 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2201 packet_put_cstring("tcpip-forward");
2202 packet_put_char(0); /* boolean: want reply */
2203 packet_put_cstring(address_to_bind);
2204 packet_put_int(listen_port);
2206 packet_write_wait();
2207 /* Assume that server accepts the request */
2210 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2211 packet_put_int(listen_port);
2212 packet_put_cstring(host_to_connect);
2213 packet_put_int(port_to_connect);
2215 packet_write_wait();
2217 /* Wait for response from the remote side. */
2218 type = packet_read(&payload_len);
2220 case SSH_SMSG_SUCCESS:
2223 case SSH_SMSG_FAILURE:
2224 log("Warning: Server denied remote port forwarding.");
2227 /* Unknown packet */
2228 packet_disconnect("Protocol error for port forward request:"
2229 "received packet type %d.", type);
2233 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2234 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2235 permitted_opens[num_permitted_opens].listen_port = listen_port;
2236 num_permitted_opens++;
2241 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2242 * listening for the port, and sends back a success reply (or disconnect
2243 * message if there was an error). This never returns if there was an error.
2247 channel_input_port_forward_request(int is_root, int gateway_ports)
2249 u_short port, host_port;
2252 /* Get arguments from the packet. */
2253 port = packet_get_int();
2254 hostname = packet_get_string(NULL);
2255 host_port = packet_get_int();
2259 * Check that an unprivileged user is not trying to forward a
2262 if (port < IPPORT_RESERVED && !is_root)
2263 packet_disconnect("Requested forwarding of port %d but user is not root.",
2266 /* Initiate forwarding */
2267 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2269 /* Free the argument string. */
2274 * Permits opening to any host/port if permitted_opens[] is empty. This is
2275 * usually called by the server, because the user could connect to any port
2276 * anyway, and the server has no way to know but to trust the client anyway.
2279 channel_permit_all_opens(void)
2281 if (num_permitted_opens == 0)
2282 all_opens_permitted = 1;
2286 channel_add_permitted_opens(char *host, int port)
2288 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2289 fatal("channel_request_remote_forwarding: too many forwards");
2290 debug("allow port forwarding to host %s port %d", host, port);
2292 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2293 permitted_opens[num_permitted_opens].port_to_connect = port;
2294 num_permitted_opens++;
2296 all_opens_permitted = 0;
2300 channel_clear_permitted_opens(void)
2304 for (i = 0; i < num_permitted_opens; i++)
2305 xfree(permitted_opens[i].host_to_connect);
2306 num_permitted_opens = 0;
2311 /* return socket to remote host, port */
2313 connect_to(const char *host, u_short port)
2315 struct addrinfo hints, *ai, *aitop;
2316 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2320 memset(&hints, 0, sizeof(hints));
2321 hints.ai_family = IPv4or6;
2322 hints.ai_socktype = SOCK_STREAM;
2323 snprintf(strport, sizeof strport, "%d", port);
2324 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2325 error("connect_to %.100s: unknown host (%s)", host,
2326 gai_strerror(gaierr));
2329 for (ai = aitop; ai; ai = ai->ai_next) {
2330 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2332 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2333 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2334 error("connect_to: getnameinfo failed");
2337 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2339 error("socket: %.100s", strerror(errno));
2342 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2343 fatal("connect_to: F_SETFL: %s", strerror(errno));
2344 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2345 errno != EINPROGRESS) {
2346 error("connect_to %.100s port %s: %.100s", ntop, strport,
2349 continue; /* fail -- try next */
2351 break; /* success */
2354 freeaddrinfo(aitop);
2356 error("connect_to %.100s port %d: failed.", host, port);
2364 channel_connect_by_listen_address(u_short listen_port)
2368 for (i = 0; i < num_permitted_opens; i++)
2369 if (permitted_opens[i].listen_port == listen_port)
2371 permitted_opens[i].host_to_connect,
2372 permitted_opens[i].port_to_connect);
2373 error("WARNING: Server requests forwarding for unknown listen_port %d",
2378 /* Check if connecting to that port is permitted and connect. */
2380 channel_connect_to(const char *host, u_short port)
2384 permit = all_opens_permitted;
2386 for (i = 0; i < num_permitted_opens; i++)
2387 if (permitted_opens[i].port_to_connect == port &&
2388 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2393 log("Received request to connect to host %.100s port %d, "
2394 "but the request was denied.", host, port);
2397 return connect_to(host, port);
2400 /* -- X11 forwarding */
2403 * Creates an internet domain socket for listening for X11 connections.
2404 * Returns a suitable display number for the DISPLAY variable, or -1 if
2408 x11_create_display_inet(int x11_display_offset, int gateway_ports)
2410 int display_number, sock;
2412 struct addrinfo hints, *ai, *aitop;
2413 char strport[NI_MAXSERV];
2414 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2416 for (display_number = x11_display_offset;
2417 display_number < MAX_DISPLAYS;
2419 port = 6000 + display_number;
2420 memset(&hints, 0, sizeof(hints));
2421 hints.ai_family = IPv4or6;
2422 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2423 hints.ai_socktype = SOCK_STREAM;
2424 snprintf(strport, sizeof strport, "%d", port);
2425 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2426 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2429 for (ai = aitop; ai; ai = ai->ai_next) {
2430 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2432 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2434 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2435 error("socket: %.100s", strerror(errno));
2438 debug("x11_create_display_inet: Socket family %d not supported",
2443 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2444 debug("bind port %d: %.100s", port, strerror(errno));
2450 for (n = 0; n < num_socks; n++) {
2456 socks[num_socks++] = sock;
2457 #ifndef DONT_TRY_OTHER_AF
2458 if (num_socks == NUM_SOCKS)
2464 freeaddrinfo(aitop);
2468 if (display_number >= MAX_DISPLAYS) {
2469 error("Failed to allocate internet-domain X11 display socket.");
2472 /* Start listening for connections on the socket. */
2473 for (n = 0; n < num_socks; n++) {
2475 if (listen(sock, 5) < 0) {
2476 error("listen: %.100s", strerror(errno));
2482 /* Allocate a channel for each socket. */
2483 for (n = 0; n < num_socks; n++) {
2485 (void) channel_new("x11 listener",
2486 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2487 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2488 0, xstrdup("X11 inet listener"), 1);
2491 /* Return the display number for the DISPLAY environment variable. */
2492 return display_number;
2496 connect_local_xsocket(u_int dnr)
2499 struct sockaddr_un addr;
2501 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2503 error("socket: %.100s", strerror(errno));
2504 memset(&addr, 0, sizeof(addr));
2505 addr.sun_family = AF_UNIX;
2506 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2507 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2510 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2515 x11_connect_display(void)
2517 int display_number, sock = 0, on = 1;
2518 const char *display;
2519 char buf[1024], *cp;
2520 struct addrinfo hints, *ai, *aitop;
2521 char strport[NI_MAXSERV];
2524 /* Try to open a socket for the local X server. */
2525 display = getenv("DISPLAY");
2527 error("DISPLAY not set.");
2531 * Now we decode the value of the DISPLAY variable and make a
2532 * connection to the real X server.
2536 * Check if it is a unix domain socket. Unix domain displays are in
2537 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2539 if (strncmp(display, "unix:", 5) == 0 ||
2540 display[0] == ':') {
2541 /* Connect to the unix domain socket. */
2542 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2543 error("Could not parse display number from DISPLAY: %.100s",
2547 /* Create a socket. */
2548 sock = connect_local_xsocket(display_number);
2552 /* OK, we now have a connection to the display. */
2556 * Connect to an inet socket. The DISPLAY value is supposedly
2557 * hostname:d[.s], where hostname may also be numeric IP address.
2559 strlcpy(buf, display, sizeof(buf));
2560 cp = strchr(buf, ':');
2562 error("Could not find ':' in DISPLAY: %.100s", display);
2566 /* buf now contains the host name. But first we parse the display number. */
2567 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2568 error("Could not parse display number from DISPLAY: %.100s",
2573 /* Look up the host address */
2574 memset(&hints, 0, sizeof(hints));
2575 hints.ai_family = IPv4or6;
2576 hints.ai_socktype = SOCK_STREAM;
2577 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2578 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2579 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2582 for (ai = aitop; ai; ai = ai->ai_next) {
2583 /* Create a socket. */
2584 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2586 debug("socket: %.100s", strerror(errno));
2589 /* Connect it to the display. */
2590 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2591 debug("connect %.100s port %d: %.100s", buf,
2592 6000 + display_number, strerror(errno));
2599 freeaddrinfo(aitop);
2601 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2605 if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on) == -1)
2606 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
2611 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2612 * the remote channel number. We should do whatever we want, and respond
2613 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2617 x11_input_open(int type, int plen, void *ctxt)
2620 int remote_id, sock = 0;
2623 debug("Received X11 open request.");
2625 remote_id = packet_get_int();
2627 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2628 remote_host = packet_get_string(NULL);
2630 remote_host = xstrdup("unknown (remote did not supply name)");
2634 /* Obtain a connection to the real X display. */
2635 sock = x11_connect_display();
2637 /* Allocate a channel for this connection. */
2638 c = channel_new("connected x11 socket",
2639 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2642 error("x11_input_open: channel_new failed");
2645 c->remote_id = remote_id;
2650 /* Send refusal to the remote host. */
2651 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2652 packet_put_int(remote_id);
2654 /* Send a confirmation to the remote host. */
2655 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2656 packet_put_int(remote_id);
2657 packet_put_int(c->self);
2662 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2664 deny_input_open(int type, int plen, void *ctxt)
2666 int rchan = packet_get_int();
2668 case SSH_SMSG_AGENT_OPEN:
2669 error("Warning: ssh server tried agent forwarding.");
2671 case SSH_SMSG_X11_OPEN:
2672 error("Warning: ssh server tried X11 forwarding.");
2675 error("deny_input_open: type %d plen %d", type, plen);
2678 error("Warning: this is probably a break in attempt by a malicious server.");
2679 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2680 packet_put_int(rchan);
2685 * Requests forwarding of X11 connections, generates fake authentication
2686 * data, and enables authentication spoofing.
2687 * This should be called in the client only.
2690 x11_request_forwarding_with_spoofing(int client_session_id,
2691 const char *proto, const char *data)
2693 u_int data_len = (u_int) strlen(data) / 2;
2694 u_int i, value, len;
2700 cp = getenv("DISPLAY");
2702 cp = strchr(cp, ':');
2704 cp = strchr(cp, '.');
2706 screen_number = atoi(cp + 1);
2710 /* Save protocol name. */
2711 x11_saved_proto = xstrdup(proto);
2714 * Extract real authentication data and generate fake data of the
2717 x11_saved_data = xmalloc(data_len);
2718 x11_fake_data = xmalloc(data_len);
2719 for (i = 0; i < data_len; i++) {
2720 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2721 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2723 rand = arc4random();
2724 x11_saved_data[i] = value;
2725 x11_fake_data[i] = rand & 0xff;
2728 x11_saved_data_len = data_len;
2729 x11_fake_data_len = data_len;
2731 /* Convert the fake data into hex. */
2732 len = 2 * data_len + 1;
2733 new_data = xmalloc(len);
2734 for (i = 0; i < data_len; i++)
2735 snprintf(new_data + 2 * i, len - 2 * i,
2736 "%02x", (u_char) x11_fake_data[i]);
2738 /* Send the request packet. */
2740 channel_request_start(client_session_id, "x11-req", 0);
2741 packet_put_char(0); /* XXX bool single connection */
2743 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2745 packet_put_cstring(proto);
2746 packet_put_cstring(new_data);
2747 packet_put_int(screen_number);
2749 packet_write_wait();
2754 /* -- agent forwarding */
2756 /* Sends a message to the server to request authentication fd forwarding. */
2759 auth_request_forwarding(void)
2761 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2763 packet_write_wait();
2767 * Returns the name of the forwarded authentication socket. Returns NULL if
2768 * there is no forwarded authentication socket. The returned value points to
2773 auth_get_socket_name(void)
2775 return auth_sock_name;
2778 /* removes the agent forwarding socket */
2781 auth_sock_cleanup_proc(void *_pw)
2783 struct passwd *pw = _pw;
2785 if (auth_sock_name) {
2786 temporarily_use_uid(pw);
2787 unlink(auth_sock_name);
2788 rmdir(auth_sock_dir);
2789 auth_sock_name = NULL;
2795 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2796 * This starts forwarding authentication requests.
2800 auth_input_request_forwarding(struct passwd * pw)
2804 struct sockaddr_un sunaddr;
2806 if (auth_get_socket_name() != NULL) {
2807 error("authentication forwarding requested twice.");
2811 /* Temporarily drop privileged uid for mkdir/bind. */
2812 temporarily_use_uid(pw);
2814 /* Allocate a buffer for the socket name, and format the name. */
2815 auth_sock_name = xmalloc(MAXPATHLEN);
2816 auth_sock_dir = xmalloc(MAXPATHLEN);
2817 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2819 /* Create private directory for socket */
2820 if (mkdtemp(auth_sock_dir) == NULL) {
2821 packet_send_debug("Agent forwarding disabled: "
2822 "mkdtemp() failed: %.100s", strerror(errno));
2824 xfree(auth_sock_name);
2825 xfree(auth_sock_dir);
2826 auth_sock_name = NULL;
2827 auth_sock_dir = NULL;
2830 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2831 auth_sock_dir, (int) getpid());
2833 /* delete agent socket on fatal() */
2834 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2836 /* Create the socket. */
2837 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2839 packet_disconnect("socket: %.100s", strerror(errno));
2841 /* Bind it to the name. */
2842 memset(&sunaddr, 0, sizeof(sunaddr));
2843 sunaddr.sun_family = AF_UNIX;
2844 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
2846 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2847 packet_disconnect("bind: %.100s", strerror(errno));
2849 /* Restore the privileged uid. */
2852 /* Start listening on the socket. */
2853 if (listen(sock, 5) < 0)
2854 packet_disconnect("listen: %.100s", strerror(errno));
2856 /* Allocate a channel for the authentication agent socket. */
2857 nc = channel_new("auth socket",
2858 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2859 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2860 0, xstrdup("auth socket"), 1);
2862 error("auth_input_request_forwarding: channel_new failed");
2863 auth_sock_cleanup_proc(pw);
2864 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2868 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2872 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2875 auth_input_open_request(int type, int plen, void *ctxt)
2878 int remote_id, sock;
2881 packet_integrity_check(plen, 4, type);
2883 /* Read the remote channel number from the message. */
2884 remote_id = packet_get_int();
2887 * Get a connection to the local authentication agent (this may again
2890 sock = ssh_get_authentication_socket();
2893 * If we could not connect the agent, send an error message back to
2894 * the server. This should never happen unless the agent dies,
2895 * because authentication forwarding is only enabled if we have an
2899 name = xstrdup("authentication agent connection");
2900 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2901 -1, 0, 0, 0, name, 1);
2903 error("auth_input_open_request: channel_new failed");
2907 c->remote_id = remote_id;
2912 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2913 packet_put_int(remote_id);
2915 /* Send a confirmation to the remote host. */
2916 debug("Forwarding authentication connection.");
2917 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2918 packet_put_int(remote_id);
2919 packet_put_int(c->self);