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 1.135 2001/10/01 21:38:53 markus Exp $");
62 * Pointer to an array containing all allocated channels. The array is
63 * dynamically extended as needed.
65 static Channel **channels = NULL;
68 * Size of the channel array. All slots of the array must always be
69 * initialized (at least the type field); unused slots set to NULL
71 static int channels_alloc = 0;
74 * Maximum file descriptor value used in any of the channels. This is
75 * updated in channel_new.
77 static int channel_max_fd = 0;
80 /* -- tcp forwarding */
83 * Data structure for storing which hosts are permitted for forward requests.
84 * The local sides of any remote forwards are stored in this array to prevent
85 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
86 * network (which might be behind a firewall).
89 char *host_to_connect; /* Connect to 'host'. */
90 u_short port_to_connect; /* Connect to 'port'. */
91 u_short listen_port; /* Remote side should listen port number. */
94 /* List of all permitted host/port pairs to connect. */
95 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
97 /* Number of permitted host/port pairs in the array. */
98 static int num_permitted_opens = 0;
100 * If this is true, all opens are permitted. This is the case on the server
101 * on which we have to trust the client anyway, and the user could do
102 * anything after logging in anyway.
104 static int all_opens_permitted = 0;
107 /* -- X11 forwarding */
109 /* Maximum number of fake X11 displays to try. */
110 #define MAX_DISPLAYS 1000
112 /* Saved X11 authentication protocol name. */
113 static char *x11_saved_proto = NULL;
115 /* Saved X11 authentication data. This is the real data. */
116 static char *x11_saved_data = NULL;
117 static u_int x11_saved_data_len = 0;
120 * Fake X11 authentication data. This is what the server will be sending us;
121 * we should replace any occurrences of this by the real data.
123 static char *x11_fake_data = NULL;
124 static u_int x11_fake_data_len;
127 /* -- agent forwarding */
131 /* Name and directory of socket for authentication agent forwarding. */
132 static char *auth_sock_name = NULL;
133 static char *auth_sock_dir = NULL;
135 /* AF_UNSPEC or AF_INET or AF_INET6 */
136 static int IPv4or6 = AF_UNSPEC;
139 static void port_open_helper(Channel *c, char *rtype);
141 /* -- channel core */
144 channel_lookup(int id)
148 if (id < 0 || id > channels_alloc) {
149 log("channel_lookup: %d: bad id", id);
154 log("channel_lookup: %d: bad id: channel free", id);
161 * Register filedescriptors for a channel, used when allocating a channel or
162 * when the channel consumer/producer is ready, e.g. shell exec'd
166 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
167 int extusage, int nonblock)
169 /* Update the maximum file descriptor value. */
170 channel_max_fd = MAX(channel_max_fd, rfd);
171 channel_max_fd = MAX(channel_max_fd, wfd);
172 channel_max_fd = MAX(channel_max_fd, efd);
174 /* XXX set close-on-exec -markus */
178 c->sock = (rfd == wfd) ? rfd : -1;
180 c->extended_usage = extusage;
182 /* XXX ugly hack: nonblock is only set by the server */
183 if (nonblock && isatty(c->rfd)) {
184 debug("channel %d: rfd %d isatty", c->self, c->rfd);
186 if (!isatty(c->wfd)) {
187 error("channel %d: wfd %d is not a tty?",
194 /* enable nonblocking mode */
206 * Allocate a new channel object and set its type and socket. This will cause
207 * remote_name to be freed.
211 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
212 int window, int maxpack, int extusage, char *remote_name, int nonblock)
217 /* Do initial allocation if this is the first call. */
218 if (channels_alloc == 0) {
221 channels = xmalloc(channels_alloc * sizeof(Channel *));
222 for (i = 0; i < channels_alloc; i++)
224 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
226 /* Try to find a free slot where to put the new channel. */
227 for (found = -1, i = 0; i < channels_alloc; i++)
228 if (channels[i] == NULL) {
229 /* Found a free slot. */
234 /* There are no free slots. Take last+1 slot and expand the array. */
235 found = channels_alloc;
236 channels_alloc += 10;
237 debug2("channel: expanding %d", channels_alloc);
238 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
239 for (i = found; i < channels_alloc; i++)
242 /* Initialize and return new channel. */
243 c = channels[found] = xmalloc(sizeof(Channel));
244 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;
264 c->detach_user = NULL;
265 c->input_filter = NULL;
266 debug("channel %d: new [%s]", found, remote_name);
271 channel_find_maxfd(void)
276 for (i = 0; i < channels_alloc; i++) {
279 max = MAX(max, c->rfd);
280 max = MAX(max, c->wfd);
281 max = MAX(max, c->efd);
288 channel_close_fd(int *fdp)
290 int ret = 0, fd = *fdp;
295 if (fd == channel_max_fd)
296 channel_max_fd = channel_find_maxfd();
301 /* Close all channel fd/socket. */
304 channel_close_fds(Channel *c)
306 debug3("channel_close_fds: channel %d: r %d w %d e %d",
307 c->self, c->rfd, c->wfd, c->efd);
309 channel_close_fd(&c->sock);
310 channel_close_fd(&c->rfd);
311 channel_close_fd(&c->wfd);
312 channel_close_fd(&c->efd);
315 /* Free the channel and close its fd/socket. */
318 channel_free(Channel *c)
323 for (n = 0, i = 0; i < channels_alloc; i++)
326 debug("channel_free: channel %d: %s, nchannels %d", c->self,
327 c->remote_name ? c->remote_name : "???", n);
329 s = channel_open_message();
330 debug3("channel_free: status: %s", s);
333 if (c->detach_user != NULL) {
334 debug("channel_free: channel %d: detaching channel user", c->self);
335 c->detach_user(c->self, NULL);
338 shutdown(c->sock, SHUT_RDWR);
339 channel_close_fds(c);
340 buffer_free(&c->input);
341 buffer_free(&c->output);
342 buffer_free(&c->extended);
343 if (c->remote_name) {
344 xfree(c->remote_name);
345 c->remote_name = NULL;
347 channels[c->self] = NULL;
352 channel_free_all(void)
356 for (i = 0; i < channels_alloc; i++)
357 if (channels[i] != NULL)
358 channel_free(channels[i]);
362 channel_detach_all(void)
367 for (i = 0; i < channels_alloc; i++) {
369 if (c != NULL && c->detach_user != NULL) {
370 debug("channel_detach_all: channel %d", c->self);
371 c->detach_user(c->self, NULL);
372 c->detach_user = NULL;
378 * Closes the sockets/fds of all channels. This is used to close extra file
379 * descriptors after a fork.
387 for (i = 0; i < channels_alloc; i++)
388 if (channels[i] != NULL)
389 channel_close_fds(channels[i]);
393 * Stop listening to channels.
397 channel_stop_listening(void)
402 for (i = 0; i < channels_alloc; i++) {
406 case SSH_CHANNEL_AUTH_SOCKET:
407 case SSH_CHANNEL_PORT_LISTENER:
408 case SSH_CHANNEL_RPORT_LISTENER:
409 case SSH_CHANNEL_X11_LISTENER:
410 channel_close_fd(&c->sock);
419 * Returns true if no channel has too much buffered data, and false if one or
420 * more channel is overfull.
424 channel_not_very_much_buffered_data()
429 for (i = 0; i < channels_alloc; i++) {
431 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
432 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
433 debug("channel %d: big input buffer %d",
434 c->self, buffer_len(&c->input));
437 if (buffer_len(&c->output) > packet_get_maxsize()) {
438 debug("channel %d: big output buffer %d",
439 c->self, buffer_len(&c->output));
447 /* Returns true if any channel is still open. */
455 for (i = 0; i < channels_alloc; i++) {
460 case SSH_CHANNEL_X11_LISTENER:
461 case SSH_CHANNEL_PORT_LISTENER:
462 case SSH_CHANNEL_RPORT_LISTENER:
463 case SSH_CHANNEL_CLOSED:
464 case SSH_CHANNEL_AUTH_SOCKET:
465 case SSH_CHANNEL_DYNAMIC:
466 case SSH_CHANNEL_CONNECTING:
467 case SSH_CHANNEL_ZOMBIE:
469 case SSH_CHANNEL_LARVAL:
471 fatal("cannot happen: SSH_CHANNEL_LARVAL");
473 case SSH_CHANNEL_OPENING:
474 case SSH_CHANNEL_OPEN:
475 case SSH_CHANNEL_X11_OPEN:
477 case SSH_CHANNEL_INPUT_DRAINING:
478 case SSH_CHANNEL_OUTPUT_DRAINING:
480 fatal("cannot happen: OUT_DRAIN");
483 fatal("channel_still_open: bad channel type %d", c->type);
490 /* Returns the id of an open channel suitable for keepaliving */
498 for (i = 0; i < channels_alloc; i++) {
503 case SSH_CHANNEL_CLOSED:
504 case SSH_CHANNEL_DYNAMIC:
505 case SSH_CHANNEL_X11_LISTENER:
506 case SSH_CHANNEL_PORT_LISTENER:
507 case SSH_CHANNEL_RPORT_LISTENER:
508 case SSH_CHANNEL_OPENING:
509 case SSH_CHANNEL_CONNECTING:
510 case SSH_CHANNEL_ZOMBIE:
512 case SSH_CHANNEL_LARVAL:
513 case SSH_CHANNEL_AUTH_SOCKET:
514 case SSH_CHANNEL_OPEN:
515 case SSH_CHANNEL_X11_OPEN:
517 case SSH_CHANNEL_INPUT_DRAINING:
518 case SSH_CHANNEL_OUTPUT_DRAINING:
520 fatal("cannot happen: OUT_DRAIN");
523 fatal("channel_find_open: bad channel type %d", c->type);
532 * Returns a message describing the currently open forwarded connections,
533 * suitable for sending to the client. The message contains crlf pairs for
538 channel_open_message()
545 buffer_init(&buffer);
546 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
547 buffer_append(&buffer, buf, strlen(buf));
548 for (i = 0; i < channels_alloc; i++) {
553 case SSH_CHANNEL_X11_LISTENER:
554 case SSH_CHANNEL_PORT_LISTENER:
555 case SSH_CHANNEL_RPORT_LISTENER:
556 case SSH_CHANNEL_CLOSED:
557 case SSH_CHANNEL_AUTH_SOCKET:
558 case SSH_CHANNEL_ZOMBIE:
560 case SSH_CHANNEL_LARVAL:
561 case SSH_CHANNEL_OPENING:
562 case SSH_CHANNEL_CONNECTING:
563 case SSH_CHANNEL_DYNAMIC:
564 case SSH_CHANNEL_OPEN:
565 case SSH_CHANNEL_X11_OPEN:
566 case SSH_CHANNEL_INPUT_DRAINING:
567 case SSH_CHANNEL_OUTPUT_DRAINING:
568 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
569 c->self, c->remote_name,
570 c->type, c->remote_id,
571 c->istate, buffer_len(&c->input),
572 c->ostate, buffer_len(&c->output),
574 buffer_append(&buffer, buf, strlen(buf));
577 fatal("channel_open_message: bad channel type %d", c->type);
581 buffer_append(&buffer, "\0", 1);
582 cp = xstrdup(buffer_ptr(&buffer));
583 buffer_free(&buffer);
588 channel_send_open(int id)
590 Channel *c = channel_lookup(id);
592 log("channel_send_open: %d: bad id", id);
595 debug("send channel open %d", id);
596 packet_start(SSH2_MSG_CHANNEL_OPEN);
597 packet_put_cstring(c->ctype);
598 packet_put_int(c->self);
599 packet_put_int(c->local_window);
600 packet_put_int(c->local_maxpacket);
605 channel_request(int id, char *service, int wantconfirm)
607 channel_request_start(id, service, wantconfirm);
609 debug("channel request %d: %s", id, service) ;
612 channel_request_start(int id, char *service, int wantconfirm)
614 Channel *c = channel_lookup(id);
616 log("channel_request: %d: bad id", id);
619 packet_start(SSH2_MSG_CHANNEL_REQUEST);
620 packet_put_int(c->remote_id);
621 packet_put_cstring(service);
622 packet_put_char(wantconfirm);
625 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
627 Channel *c = channel_lookup(id);
629 log("channel_register_callback: %d: bad id", id);
637 channel_register_cleanup(int id, channel_callback_fn *fn)
639 Channel *c = channel_lookup(id);
641 log("channel_register_cleanup: %d: bad id", id);
647 channel_cancel_cleanup(int id)
649 Channel *c = channel_lookup(id);
651 log("channel_cancel_cleanup: %d: bad id", id);
654 c->detach_user = NULL;
657 channel_register_filter(int id, channel_filter_fn *fn)
659 Channel *c = channel_lookup(id);
661 log("channel_register_filter: %d: bad id", id);
664 c->input_filter = fn;
668 channel_set_fds(int id, int rfd, int wfd, int efd,
669 int extusage, int nonblock)
671 Channel *c = channel_lookup(id);
672 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
673 fatal("channel_activate for non-larval channel %d.", id);
674 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
675 c->type = SSH_CHANNEL_OPEN;
676 /* XXX window size? */
677 c->local_window = c->local_window_max = c->local_maxpacket * 2;
678 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
679 packet_put_int(c->remote_id);
680 packet_put_int(c->local_window);
685 * 'channel_pre*' are called just before select() to add any bits relevant to
686 * channels in the select bitmasks.
689 * 'channel_post*': perform any appropriate operations for channels which
690 * have events pending.
692 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
693 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
694 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
697 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
699 FD_SET(c->sock, readset);
703 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
705 debug3("channel %d: waiting for connection", c->self);
706 FD_SET(c->sock, writeset);
710 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
712 if (buffer_len(&c->input) < packet_get_maxsize())
713 FD_SET(c->sock, readset);
714 if (buffer_len(&c->output) > 0)
715 FD_SET(c->sock, writeset);
719 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
721 /* test whether sockets are 'alive' for read/write */
722 if (c->istate == CHAN_INPUT_OPEN)
723 if (buffer_len(&c->input) < packet_get_maxsize())
724 FD_SET(c->sock, readset);
725 if (c->ostate == CHAN_OUTPUT_OPEN ||
726 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
727 if (buffer_len(&c->output) > 0) {
728 FD_SET(c->sock, writeset);
729 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
736 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
738 if (c->istate == CHAN_INPUT_OPEN &&
739 c->remote_window > 0 &&
740 buffer_len(&c->input) < c->remote_window)
741 FD_SET(c->rfd, readset);
742 if (c->ostate == CHAN_OUTPUT_OPEN ||
743 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
744 if (buffer_len(&c->output) > 0) {
745 FD_SET(c->wfd, writeset);
746 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
750 /** XXX check close conditions, too */
752 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
753 buffer_len(&c->extended) > 0)
754 FD_SET(c->efd, writeset);
755 else if (c->extended_usage == CHAN_EXTENDED_READ &&
756 buffer_len(&c->extended) < c->remote_window)
757 FD_SET(c->efd, readset);
762 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
764 if (buffer_len(&c->input) == 0) {
765 packet_start(SSH_MSG_CHANNEL_CLOSE);
766 packet_put_int(c->remote_id);
768 c->type = SSH_CHANNEL_CLOSED;
769 debug("channel %d: closing after input drain.", c->self);
774 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
776 if (buffer_len(&c->output) == 0)
779 FD_SET(c->sock, writeset);
783 * This is a special state for X11 authentication spoofing. An opened X11
784 * connection (when authentication spoofing is being done) remains in this
785 * state until the first packet has been completely read. The authentication
786 * data in that packet is then substituted by the real data if it matches the
787 * fake data, and the channel is put into normal mode.
788 * XXX All this happens at the client side.
789 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
792 x11_open_helper(Buffer *b)
795 u_int proto_len, data_len;
797 /* Check if the fixed size part of the packet is in buffer. */
798 if (buffer_len(b) < 12)
801 /* Parse the lengths of variable-length fields. */
802 ucp = (u_char *) buffer_ptr(b);
803 if (ucp[0] == 0x42) { /* Byte order MSB first. */
804 proto_len = 256 * ucp[6] + ucp[7];
805 data_len = 256 * ucp[8] + ucp[9];
806 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
807 proto_len = ucp[6] + 256 * ucp[7];
808 data_len = ucp[8] + 256 * ucp[9];
810 debug("Initial X11 packet contains bad byte order byte: 0x%x",
815 /* Check if the whole packet is in buffer. */
817 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
820 /* Check if authentication protocol matches. */
821 if (proto_len != strlen(x11_saved_proto) ||
822 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
823 debug("X11 connection uses different authentication protocol.");
826 /* Check if authentication data matches our fake data. */
827 if (data_len != x11_fake_data_len ||
828 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
829 x11_fake_data, x11_fake_data_len) != 0) {
830 debug("X11 auth data does not match fake data.");
833 /* Check fake data length */
834 if (x11_fake_data_len != x11_saved_data_len) {
835 error("X11 fake_data_len %d != saved_data_len %d",
836 x11_fake_data_len, x11_saved_data_len);
840 * Received authentication protocol and data match
841 * our fake data. Substitute the fake data with real
844 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
845 x11_saved_data, x11_saved_data_len);
850 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
852 int ret = x11_open_helper(&c->output);
854 /* Start normal processing for the channel. */
855 c->type = SSH_CHANNEL_OPEN;
856 channel_pre_open_13(c, readset, writeset);
857 } else if (ret == -1) {
859 * We have received an X11 connection that has bad
860 * authentication information.
862 log("X11 connection rejected because of wrong authentication.");
863 buffer_clear(&c->input);
864 buffer_clear(&c->output);
865 channel_close_fd(&c->sock);
867 c->type = SSH_CHANNEL_CLOSED;
868 packet_start(SSH_MSG_CHANNEL_CLOSE);
869 packet_put_int(c->remote_id);
875 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
877 int ret = x11_open_helper(&c->output);
879 /* c->force_drain = 1; */
882 c->type = SSH_CHANNEL_OPEN;
884 channel_pre_open_20(c, readset, writeset);
886 channel_pre_open_15(c, readset, writeset);
887 } else if (ret == -1) {
888 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
889 chan_read_failed(c); /** force close? */
890 chan_write_failed(c);
891 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
895 /* try to decode a socks4 header */
897 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
900 int len, have, i, found;
906 struct in_addr dest_addr;
909 debug2("channel %d: decode socks4", c->self);
911 have = buffer_len(&c->input);
912 len = sizeof(s4_req);
915 p = buffer_ptr(&c->input);
916 for (found = 0, i = len; i < have; i++) {
922 /* the peer is probably sending garbage */
923 debug("channel %d: decode socks4: too long",
930 buffer_get(&c->input, (char *)&s4_req.version, 1);
931 buffer_get(&c->input, (char *)&s4_req.command, 1);
932 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
933 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
934 have = buffer_len(&c->input);
935 p = buffer_ptr(&c->input);
937 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
939 fatal("channel %d: decode socks4: len %d > have %d",
941 strlcpy(username, p, sizeof(username));
942 buffer_consume(&c->input, len);
943 buffer_consume(&c->input, 1); /* trailing '\0' */
945 host = inet_ntoa(s4_req.dest_addr);
946 strlcpy(c->path, host, sizeof(c->path));
947 c->host_port = ntohs(s4_req.dest_port);
949 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
950 c->self, host, c->host_port, s4_req.command);
952 if (s4_req.command != 1) {
953 debug("channel %d: cannot handle: socks4 cn %d",
954 c->self, s4_req.command);
957 s4_rsp.version = 0; /* vn: 0 for reply */
958 s4_rsp.command = 90; /* cd: req granted */
959 s4_rsp.dest_port = 0; /* ignored */
960 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
961 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
965 /* dynamic port forwarding */
967 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
972 have = buffer_len(&c->input);
974 debug2("channel %d: pre_dynamic: have %d", c->self, have);
975 /* buffer_dump(&c->input); */
976 /* check if the fixed size part of the packet is in buffer. */
979 FD_SET(c->sock, readset);
982 /* try to guess the protocol */
983 p = buffer_ptr(&c->input);
986 ret = channel_decode_socks4(c, readset, writeset);
994 } else if (ret == 0) {
995 debug2("channel %d: pre_dynamic: need more", c->self);
997 FD_SET(c->sock, readset);
999 /* switch to the next state */
1000 c->type = SSH_CHANNEL_OPENING;
1001 port_open_helper(c, "direct-tcpip");
1005 /* This is our fake X11 server socket. */
1007 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1010 struct sockaddr addr;
1013 char buf[16384], *remote_ipaddr;
1016 if (FD_ISSET(c->sock, readset)) {
1017 debug("X11 connection requested.");
1018 addrlen = sizeof(addr);
1019 newsock = accept(c->sock, &addr, &addrlen);
1021 error("accept: %.100s", strerror(errno));
1024 remote_ipaddr = get_peer_ipaddr(newsock);
1025 remote_port = get_peer_port(newsock);
1026 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1027 remote_ipaddr, remote_port);
1029 nc = channel_new("accepted x11 socket",
1030 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1031 c->local_window_max, c->local_maxpacket,
1032 0, xstrdup(buf), 1);
1035 xfree(remote_ipaddr);
1039 packet_start(SSH2_MSG_CHANNEL_OPEN);
1040 packet_put_cstring("x11");
1041 packet_put_int(nc->self);
1042 packet_put_int(c->local_window_max);
1043 packet_put_int(c->local_maxpacket);
1044 /* originator ipaddr and port */
1045 packet_put_cstring(remote_ipaddr);
1046 if (datafellows & SSH_BUG_X11FWD) {
1047 debug("ssh2 x11 bug compat mode");
1049 packet_put_int(remote_port);
1053 packet_start(SSH_SMSG_X11_OPEN);
1054 packet_put_int(nc->self);
1055 if (packet_get_protocol_flags() &
1056 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1057 packet_put_cstring(buf);
1060 xfree(remote_ipaddr);
1065 port_open_helper(Channel *c, char *rtype)
1069 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1070 u_short remote_port = get_peer_port(c->sock);
1072 direct = (strcmp(rtype, "direct-tcpip") == 0);
1074 snprintf(buf, sizeof buf,
1075 "%s: listening port %d for %.100s port %d, "
1076 "connect from %.200s port %d",
1077 rtype, c->listening_port, c->path, c->host_port,
1078 remote_ipaddr, remote_port);
1080 xfree(c->remote_name);
1081 c->remote_name = xstrdup(buf);
1084 packet_start(SSH2_MSG_CHANNEL_OPEN);
1085 packet_put_cstring(rtype);
1086 packet_put_int(c->self);
1087 packet_put_int(c->local_window_max);
1088 packet_put_int(c->local_maxpacket);
1090 /* target host, port */
1091 packet_put_cstring(c->path);
1092 packet_put_int(c->host_port);
1094 /* listen address, port */
1095 packet_put_cstring(c->path);
1096 packet_put_int(c->listening_port);
1098 /* originator host and port */
1099 packet_put_cstring(remote_ipaddr);
1100 packet_put_int(remote_port);
1103 packet_start(SSH_MSG_PORT_OPEN);
1104 packet_put_int(c->self);
1105 packet_put_cstring(c->path);
1106 packet_put_int(c->host_port);
1107 if (packet_get_protocol_flags() &
1108 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1109 packet_put_cstring(c->remote_name);
1112 xfree(remote_ipaddr);
1116 * This socket is listening for connections to a forwarded TCP/IP port.
1119 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1122 struct sockaddr addr;
1123 int newsock, nextstate;
1127 if (FD_ISSET(c->sock, readset)) {
1128 debug("Connection to port %d forwarding "
1129 "to %.100s port %d requested.",
1130 c->listening_port, c->path, c->host_port);
1132 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
1133 "forwarded-tcpip" : "direct-tcpip";
1134 nextstate = (c->host_port == 0 &&
1135 c->type != SSH_CHANNEL_RPORT_LISTENER) ?
1136 SSH_CHANNEL_DYNAMIC : SSH_CHANNEL_OPENING;
1138 addrlen = sizeof(addr);
1139 newsock = accept(c->sock, &addr, &addrlen);
1141 error("accept: %.100s", strerror(errno));
1144 nc = channel_new(rtype,
1145 nextstate, newsock, newsock, -1,
1146 c->local_window_max, c->local_maxpacket,
1147 0, xstrdup(rtype), 1);
1149 error("channel_post_port_listener: no new channel:");
1153 nc->listening_port = c->listening_port;
1154 nc->host_port = c->host_port;
1155 strlcpy(nc->path, c->path, sizeof(nc->path));
1157 if (nextstate != SSH_CHANNEL_DYNAMIC)
1158 port_open_helper(nc, rtype);
1163 * This is the authentication agent socket listening for connections from
1167 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1172 struct sockaddr addr;
1175 if (FD_ISSET(c->sock, readset)) {
1176 addrlen = sizeof(addr);
1177 newsock = accept(c->sock, &addr, &addrlen);
1179 error("accept from auth socket: %.100s", strerror(errno));
1182 name = xstrdup("accepted auth socket");
1183 nc = channel_new("accepted auth socket",
1184 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1185 c->local_window_max, c->local_maxpacket,
1188 error("channel_post_auth_listener: channel_new failed");
1193 packet_start(SSH2_MSG_CHANNEL_OPEN);
1194 packet_put_cstring("auth-agent@openssh.com");
1195 packet_put_int(nc->self);
1196 packet_put_int(c->local_window_max);
1197 packet_put_int(c->local_maxpacket);
1199 packet_start(SSH_SMSG_AGENT_OPEN);
1200 packet_put_int(nc->self);
1207 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1210 socklen_t sz = sizeof(err);
1212 if (FD_ISSET(c->sock, writeset)) {
1213 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1216 error("getsockopt SO_ERROR failed");
1219 debug("channel %d: connected", c->self);
1220 c->type = SSH_CHANNEL_OPEN;
1222 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1223 packet_put_int(c->remote_id);
1224 packet_put_int(c->self);
1225 packet_put_int(c->local_window);
1226 packet_put_int(c->local_maxpacket);
1228 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1229 packet_put_int(c->remote_id);
1230 packet_put_int(c->self);
1233 debug("channel %d: not connected: %s",
1234 c->self, strerror(err));
1236 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1237 packet_put_int(c->remote_id);
1238 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1239 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1240 packet_put_cstring(strerror(err));
1241 packet_put_cstring("");
1244 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1245 packet_put_int(c->remote_id);
1254 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1260 FD_ISSET(c->rfd, readset)) {
1261 len = read(c->rfd, buf, sizeof(buf));
1262 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1265 debug("channel %d: read<=0 rfd %d len %d",
1266 c->self, c->rfd, len);
1267 if (c->type != SSH_CHANNEL_OPEN) {
1268 debug("channel %d: not open", c->self);
1271 } else if (compat13) {
1272 buffer_consume(&c->output, buffer_len(&c->output));
1273 c->type = SSH_CHANNEL_INPUT_DRAINING;
1274 debug("channel %d: input draining.", c->self);
1276 chan_read_failed(c);
1280 if(c->input_filter != NULL) {
1281 if (c->input_filter(c, buf, len) == -1) {
1282 debug("channel %d: filter stops", c->self);
1283 chan_read_failed(c);
1286 buffer_append(&c->input, buf, len);
1292 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1299 /* Send buffered output data to the socket. */
1301 FD_ISSET(c->wfd, writeset) &&
1302 buffer_len(&c->output) > 0) {
1303 data = buffer_ptr(&c->output);
1304 dlen = buffer_len(&c->output);
1305 len = write(c->wfd, data, dlen);
1306 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1309 if (c->type != SSH_CHANNEL_OPEN) {
1310 debug("channel %d: not open", c->self);
1313 } else if (compat13) {
1314 buffer_consume(&c->output, buffer_len(&c->output));
1315 debug("channel %d: input draining.", c->self);
1316 c->type = SSH_CHANNEL_INPUT_DRAINING;
1318 chan_write_failed(c);
1322 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1323 if (tcgetattr(c->wfd, &tio) == 0 &&
1324 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1326 * Simulate echo to reduce the impact of
1327 * traffic analysis. We need to match the
1328 * size of a SSH2_MSG_CHANNEL_DATA message
1329 * (4 byte channel id + data)
1331 packet_send_ignore(4 + len);
1335 buffer_consume(&c->output, len);
1336 if (compat20 && len > 0) {
1337 c->local_consumed += len;
1343 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1348 /** XXX handle drain efd, too */
1350 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1351 FD_ISSET(c->efd, writeset) &&
1352 buffer_len(&c->extended) > 0) {
1353 len = write(c->efd, buffer_ptr(&c->extended),
1354 buffer_len(&c->extended));
1355 debug2("channel %d: written %d to efd %d",
1356 c->self, len, c->efd);
1357 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1360 debug2("channel %d: closing write-efd %d",
1362 channel_close_fd(&c->efd);
1364 buffer_consume(&c->extended, len);
1365 c->local_consumed += len;
1367 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1368 FD_ISSET(c->efd, readset)) {
1369 len = read(c->efd, buf, sizeof(buf));
1370 debug2("channel %d: read %d from efd %d",
1371 c->self, len, c->efd);
1372 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1375 debug2("channel %d: closing read-efd %d",
1377 channel_close_fd(&c->efd);
1379 buffer_append(&c->extended, buf, len);
1386 channel_check_window(Channel *c)
1388 if (c->type == SSH_CHANNEL_OPEN &&
1389 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1390 c->local_window < c->local_window_max/2 &&
1391 c->local_consumed > 0) {
1392 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1393 packet_put_int(c->remote_id);
1394 packet_put_int(c->local_consumed);
1396 debug2("channel %d: window %d sent adjust %d",
1397 c->self, c->local_window,
1399 c->local_window += c->local_consumed;
1400 c->local_consumed = 0;
1406 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1408 channel_handle_rfd(c, readset, writeset);
1409 channel_handle_wfd(c, readset, writeset);
1413 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1415 channel_handle_rfd(c, readset, writeset);
1416 channel_handle_wfd(c, readset, writeset);
1417 channel_handle_efd(c, readset, writeset);
1419 channel_check_window(c);
1423 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1426 /* Send buffered output data to the socket. */
1427 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1428 len = write(c->sock, buffer_ptr(&c->output),
1429 buffer_len(&c->output));
1431 buffer_consume(&c->output, buffer_len(&c->output));
1433 buffer_consume(&c->output, len);
1438 channel_handler_init_20(void)
1440 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1441 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1442 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1443 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1444 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1445 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1446 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1447 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1449 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1450 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1451 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1452 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1453 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1454 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1455 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1459 channel_handler_init_13(void)
1461 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1462 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1463 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1464 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1465 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1466 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1467 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1468 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1469 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1471 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1472 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1473 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1474 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1475 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1476 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1477 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1481 channel_handler_init_15(void)
1483 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1484 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1485 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1486 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1487 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1488 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1489 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1491 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1492 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1493 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1494 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1495 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1496 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1500 channel_handler_init(void)
1503 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1504 channel_pre[i] = NULL;
1505 channel_post[i] = NULL;
1508 channel_handler_init_20();
1510 channel_handler_init_13();
1512 channel_handler_init_15();
1516 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1518 static int did_init = 0;
1523 channel_handler_init();
1526 for (i = 0; i < channels_alloc; i++) {
1530 if (ftab[c->type] != NULL)
1531 (*ftab[c->type])(c, readset, writeset);
1532 if (chan_is_dead(c)) {
1534 * we have to remove the fd's from the select mask
1535 * before the channels are free'd and the fd's are
1539 FD_CLR(c->wfd, writeset);
1541 FD_CLR(c->rfd, readset);
1543 if (c->extended_usage == CHAN_EXTENDED_READ)
1544 FD_CLR(c->efd, readset);
1545 if (c->extended_usage == CHAN_EXTENDED_WRITE)
1546 FD_CLR(c->efd, writeset);
1554 * Allocate/update select bitmasks and add any bits relevant to channels in
1558 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1559 int *nallocp, int rekeying)
1564 n = MAX(*maxfdp, channel_max_fd);
1566 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1567 /* perhaps check sz < nalloc/2 and shrink? */
1568 if (*readsetp == NULL || sz > *nallocp) {
1569 *readsetp = xrealloc(*readsetp, sz);
1570 *writesetp = xrealloc(*writesetp, sz);
1574 memset(*readsetp, 0, sz);
1575 memset(*writesetp, 0, sz);
1578 channel_handler(channel_pre, *readsetp, *writesetp);
1582 * After select, perform any appropriate operations for channels which have
1586 channel_after_select(fd_set * readset, fd_set * writeset)
1588 channel_handler(channel_post, readset, writeset);
1592 /* If there is data to send to the connection, enqueue some of it now. */
1595 channel_output_poll()
1600 for (i = 0; i < channels_alloc; i++) {
1606 * We are only interested in channels that can have buffered
1610 if (c->type != SSH_CHANNEL_OPEN &&
1611 c->type != SSH_CHANNEL_INPUT_DRAINING)
1614 if (c->type != SSH_CHANNEL_OPEN)
1618 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1619 /* XXX is this true? */
1620 debug2("channel %d: no data after CLOSE", c->self);
1624 /* Get the amount of buffered data for this channel. */
1625 if ((c->istate == CHAN_INPUT_OPEN ||
1626 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1627 (len = buffer_len(&c->input)) > 0) {
1629 * Send some data for the other side over the secure
1633 if (len > c->remote_window)
1634 len = c->remote_window;
1635 if (len > c->remote_maxpacket)
1636 len = c->remote_maxpacket;
1638 if (packet_is_interactive()) {
1642 /* Keep the packets at reasonable size. */
1643 if (len > packet_get_maxsize()/2)
1644 len = packet_get_maxsize()/2;
1648 packet_start(compat20 ?
1649 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1650 packet_put_int(c->remote_id);
1651 packet_put_string(buffer_ptr(&c->input), len);
1653 buffer_consume(&c->input, len);
1654 c->remote_window -= len;
1656 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1658 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1660 * input-buffer is empty and read-socket shutdown:
1661 * tell peer, that we will not send more data: send IEOF
1665 /* Send extended data, i.e. stderr */
1667 c->remote_window > 0 &&
1668 (len = buffer_len(&c->extended)) > 0 &&
1669 c->extended_usage == CHAN_EXTENDED_READ) {
1670 debug2("channel %d: rwin %d elen %d euse %d",
1671 c->self, c->remote_window, buffer_len(&c->extended),
1673 if (len > c->remote_window)
1674 len = c->remote_window;
1675 if (len > c->remote_maxpacket)
1676 len = c->remote_maxpacket;
1677 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1678 packet_put_int(c->remote_id);
1679 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1680 packet_put_string(buffer_ptr(&c->extended), len);
1682 buffer_consume(&c->extended, len);
1683 c->remote_window -= len;
1684 debug2("channel %d: sent ext data %d", c->self, len);
1690 /* -- protocol input */
1693 channel_input_data(int type, int plen, void *ctxt)
1700 /* Get the channel number and verify it. */
1701 id = packet_get_int();
1702 c = channel_lookup(id);
1704 packet_disconnect("Received data for nonexistent channel %d.", id);
1706 /* Ignore any data for non-open channels (might happen on close) */
1707 if (c->type != SSH_CHANNEL_OPEN &&
1708 c->type != SSH_CHANNEL_X11_OPEN)
1711 /* same for protocol 1.5 if output end is no longer open */
1712 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1716 data = packet_get_string(&data_len);
1720 if (data_len > c->local_maxpacket) {
1721 log("channel %d: rcvd big packet %d, maxpack %d",
1722 c->self, data_len, c->local_maxpacket);
1724 if (data_len > c->local_window) {
1725 log("channel %d: rcvd too much data %d, win %d",
1726 c->self, data_len, c->local_window);
1730 c->local_window -= data_len;
1732 packet_integrity_check(plen, 4 + 4 + data_len, type);
1734 buffer_append(&c->output, data, data_len);
1739 channel_input_extended_data(int type, int plen, void *ctxt)
1747 /* Get the channel number and verify it. */
1748 id = packet_get_int();
1749 c = channel_lookup(id);
1752 packet_disconnect("Received extended_data for bad channel %d.", id);
1753 if (c->type != SSH_CHANNEL_OPEN) {
1754 log("channel %d: ext data for non open", id);
1757 tcode = packet_get_int();
1759 c->extended_usage != CHAN_EXTENDED_WRITE ||
1760 tcode != SSH2_EXTENDED_DATA_STDERR) {
1761 log("channel %d: bad ext data", c->self);
1764 data = packet_get_string(&data_len);
1766 if (data_len > c->local_window) {
1767 log("channel %d: rcvd too much extended_data %d, win %d",
1768 c->self, data_len, c->local_window);
1772 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1773 c->local_window -= data_len;
1774 buffer_append(&c->extended, data, data_len);
1779 channel_input_ieof(int type, int plen, void *ctxt)
1784 packet_integrity_check(plen, 4, type);
1786 id = packet_get_int();
1787 c = channel_lookup(id);
1789 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1792 /* XXX force input close */
1793 if (c->force_drain) {
1794 debug("channel %d: FORCE input drain", c->self);
1795 c->istate = CHAN_INPUT_WAIT_DRAIN;
1801 channel_input_close(int type, int plen, void *ctxt)
1806 packet_integrity_check(plen, 4, type);
1808 id = packet_get_int();
1809 c = channel_lookup(id);
1811 packet_disconnect("Received close for nonexistent channel %d.", id);
1814 * Send a confirmation that we have closed the channel and no more
1815 * data is coming for it.
1817 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1818 packet_put_int(c->remote_id);
1822 * If the channel is in closed state, we have sent a close request,
1823 * and the other side will eventually respond with a confirmation.
1824 * Thus, we cannot free the channel here, because then there would be
1825 * no-one to receive the confirmation. The channel gets freed when
1826 * the confirmation arrives.
1828 if (c->type != SSH_CHANNEL_CLOSED) {
1830 * Not a closed channel - mark it as draining, which will
1831 * cause it to be freed later.
1833 buffer_consume(&c->input, buffer_len(&c->input));
1834 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1838 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1840 channel_input_oclose(int type, int plen, void *ctxt)
1842 int id = packet_get_int();
1843 Channel *c = channel_lookup(id);
1844 packet_integrity_check(plen, 4, type);
1846 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1847 chan_rcvd_oclose(c);
1851 channel_input_close_confirmation(int type, int plen, void *ctxt)
1853 int id = packet_get_int();
1854 Channel *c = channel_lookup(id);
1858 packet_disconnect("Received close confirmation for "
1859 "out-of-range channel %d.", id);
1860 if (c->type != SSH_CHANNEL_CLOSED)
1861 packet_disconnect("Received close confirmation for "
1862 "non-closed channel %d (type %d).", id, c->type);
1867 channel_input_open_confirmation(int type, int plen, void *ctxt)
1873 packet_integrity_check(plen, 4 + 4, type);
1875 id = packet_get_int();
1876 c = channel_lookup(id);
1878 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1879 packet_disconnect("Received open confirmation for "
1880 "non-opening channel %d.", id);
1881 remote_id = packet_get_int();
1882 /* Record the remote channel number and mark that the channel is now open. */
1883 c->remote_id = remote_id;
1884 c->type = SSH_CHANNEL_OPEN;
1887 c->remote_window = packet_get_int();
1888 c->remote_maxpacket = packet_get_int();
1890 if (c->cb_fn != NULL && c->cb_event == type) {
1891 debug2("callback start");
1892 c->cb_fn(c->self, c->cb_arg);
1893 debug2("callback done");
1895 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1896 c->remote_window, c->remote_maxpacket);
1901 reason2txt(int reason)
1904 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1905 return "administratively prohibited";
1906 case SSH2_OPEN_CONNECT_FAILED:
1907 return "connect failed";
1908 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1909 return "unknown channel type";
1910 case SSH2_OPEN_RESOURCE_SHORTAGE:
1911 return "resource shortage";
1913 return "unknown reason";
1917 channel_input_open_failure(int type, int plen, void *ctxt)
1920 char *msg = NULL, *lang = NULL;
1924 packet_integrity_check(plen, 4, type);
1926 id = packet_get_int();
1927 c = channel_lookup(id);
1929 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1930 packet_disconnect("Received open failure for "
1931 "non-opening channel %d.", id);
1933 reason = packet_get_int();
1934 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1935 msg = packet_get_string(NULL);
1936 lang = packet_get_string(NULL);
1939 log("channel %d: open failed: %s%s%s", id,
1940 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1946 /* Free the channel. This will also close the socket. */
1951 channel_input_channel_request(int type, int plen, void *ctxt)
1956 id = packet_get_int();
1957 c = channel_lookup(id);
1960 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1961 packet_disconnect("Received request for "
1962 "non-open channel %d.", id);
1963 if (c->cb_fn != NULL && c->cb_event == type) {
1964 debug2("callback start");
1965 c->cb_fn(c->self, c->cb_arg);
1966 debug2("callback done");
1968 char *service = packet_get_string(NULL);
1969 debug("channel %d: rcvd request for %s", c->self, service);
1970 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1976 channel_input_window_adjust(int type, int plen, void *ctxt)
1984 /* Get the channel number and verify it. */
1985 id = packet_get_int();
1986 c = channel_lookup(id);
1988 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1989 log("Received window adjust for "
1990 "non-open channel %d.", id);
1993 adjust = packet_get_int();
1995 debug2("channel %d: rcvd adjust %d", id, adjust);
1996 c->remote_window += adjust;
2000 channel_input_port_open(int type, int plen, void *ctxt)
2004 char *host, *originator_string;
2005 int remote_id, sock = -1;
2007 remote_id = packet_get_int();
2008 host = packet_get_string(NULL);
2009 host_port = packet_get_int();
2011 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2012 originator_string = packet_get_string(NULL);
2014 originator_string = xstrdup("unknown (remote did not supply name)");
2017 sock = channel_connect_to(host, host_port);
2019 c = channel_new("connected socket",
2020 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2021 originator_string, 1);
2023 error("channel_input_port_open: channel_new failed");
2026 c->remote_id = remote_id;
2030 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2031 packet_put_int(remote_id);
2038 /* -- tcp forwarding */
2041 channel_set_af(int af)
2047 * Initiate forwarding of connections to local port "port" through the secure
2048 * channel to host:port from remote side.
2051 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2052 u_short port_to_connect, int gateway_ports)
2054 return channel_request_forwarding(
2056 host_to_connect, port_to_connect,
2057 gateway_ports, /*remote_fwd*/ 0);
2061 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2062 * (SSH_CHANNEL_RPORT_LISTENER).
2065 channel_request_forwarding(
2066 const char *listen_address, u_short listen_port,
2067 const char *host_to_connect, u_short port_to_connect,
2068 int gateway_ports, int remote_fwd)
2071 int success, sock, on = 1, type;
2072 struct addrinfo hints, *ai, *aitop;
2073 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2075 struct linger linger;
2080 host = listen_address;
2081 type = SSH_CHANNEL_RPORT_LISTENER;
2083 host = host_to_connect;
2084 type = SSH_CHANNEL_PORT_LISTENER;
2087 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2088 error("Forward host name too long.");
2092 /* XXX listen_address is currently ignored */
2094 * getaddrinfo returns a loopback address if the hostname is
2095 * set to NULL and hints.ai_flags is not AI_PASSIVE
2097 memset(&hints, 0, sizeof(hints));
2098 hints.ai_family = IPv4or6;
2099 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2100 hints.ai_socktype = SOCK_STREAM;
2101 snprintf(strport, sizeof strport, "%d", listen_port);
2102 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2103 packet_disconnect("getaddrinfo: fatal error");
2105 for (ai = aitop; ai; ai = ai->ai_next) {
2106 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2108 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2109 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2110 error("channel_request_forwarding: getnameinfo failed");
2113 /* Create a port to listen for the host. */
2114 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2116 /* this is no error since kernel may not support ipv6 */
2117 verbose("socket: %.100s", strerror(errno));
2121 * Set socket options. We would like the socket to disappear
2122 * as soon as it has been closed for whatever reason.
2124 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2126 linger.l_linger = 5;
2127 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2128 debug("Local forwarding listening on %s port %s.", ntop, strport);
2130 /* Bind the socket to the address. */
2131 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2132 /* address can be in use ipv6 address is already bound */
2134 error("bind: %.100s", strerror(errno));
2136 verbose("bind: %.100s", strerror(errno));
2141 /* Start listening for connections on the socket. */
2142 if (listen(sock, 5) < 0) {
2143 error("listen: %.100s", strerror(errno));
2147 /* Allocate a channel number for the socket. */
2148 c = channel_new("port listener", type, sock, sock, -1,
2149 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2150 0, xstrdup("port listener"), 1);
2152 error("channel_request_forwarding: channel_new failed");
2156 strlcpy(c->path, host, sizeof(c->path));
2157 c->host_port = port_to_connect;
2158 c->listening_port = listen_port;
2162 error("channel_request_forwarding: cannot listen to port: %d",
2164 freeaddrinfo(aitop);
2169 * Initiate forwarding of connections to port "port" on remote host through
2170 * the secure channel to host:port from local side.
2174 channel_request_remote_forwarding(u_short listen_port,
2175 const char *host_to_connect, u_short port_to_connect)
2177 int payload_len, type, success = 0;
2179 /* Record locally that connection to this host/port is permitted. */
2180 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2181 fatal("channel_request_remote_forwarding: too many forwards");
2183 /* Send the forward request to the remote side. */
2185 const char *address_to_bind = "0.0.0.0";
2186 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2187 packet_put_cstring("tcpip-forward");
2188 packet_put_char(0); /* boolean: want reply */
2189 packet_put_cstring(address_to_bind);
2190 packet_put_int(listen_port);
2192 packet_write_wait();
2193 /* Assume that server accepts the request */
2196 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2197 packet_put_int(listen_port);
2198 packet_put_cstring(host_to_connect);
2199 packet_put_int(port_to_connect);
2201 packet_write_wait();
2203 /* Wait for response from the remote side. */
2204 type = packet_read(&payload_len);
2206 case SSH_SMSG_SUCCESS:
2209 case SSH_SMSG_FAILURE:
2210 log("Warning: Server denied remote port forwarding.");
2213 /* Unknown packet */
2214 packet_disconnect("Protocol error for port forward request:"
2215 "received packet type %d.", type);
2219 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2220 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2221 permitted_opens[num_permitted_opens].listen_port = listen_port;
2222 num_permitted_opens++;
2227 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2228 * listening for the port, and sends back a success reply (or disconnect
2229 * message if there was an error). This never returns if there was an error.
2233 channel_input_port_forward_request(int is_root, int gateway_ports)
2235 u_short port, host_port;
2238 /* Get arguments from the packet. */
2239 port = packet_get_int();
2240 hostname = packet_get_string(NULL);
2241 host_port = packet_get_int();
2245 * Check that an unprivileged user is not trying to forward a
2248 if (port < IPPORT_RESERVED && !is_root)
2249 packet_disconnect("Requested forwarding of port %d but user is not root.",
2252 /* Initiate forwarding */
2253 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2255 /* Free the argument string. */
2260 * Permits opening to any host/port if permitted_opens[] is empty. This is
2261 * usually called by the server, because the user could connect to any port
2262 * anyway, and the server has no way to know but to trust the client anyway.
2265 channel_permit_all_opens()
2267 if (num_permitted_opens == 0)
2268 all_opens_permitted = 1;
2272 channel_add_permitted_opens(char *host, int port)
2274 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2275 fatal("channel_request_remote_forwarding: too many forwards");
2276 debug("allow port forwarding to host %s port %d", host, port);
2278 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2279 permitted_opens[num_permitted_opens].port_to_connect = port;
2280 num_permitted_opens++;
2282 all_opens_permitted = 0;
2286 channel_clear_permitted_opens(void)
2290 for (i = 0; i < num_permitted_opens; i++)
2291 xfree(permitted_opens[i].host_to_connect);
2292 num_permitted_opens = 0;
2297 /* return socket to remote host, port */
2299 connect_to(const char *host, u_short port)
2301 struct addrinfo hints, *ai, *aitop;
2302 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2306 memset(&hints, 0, sizeof(hints));
2307 hints.ai_family = IPv4or6;
2308 hints.ai_socktype = SOCK_STREAM;
2309 snprintf(strport, sizeof strport, "%d", port);
2310 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2311 error("connect_to %.100s: unknown host (%s)", host,
2312 gai_strerror(gaierr));
2315 for (ai = aitop; ai; ai = ai->ai_next) {
2316 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2318 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2319 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2320 error("connect_to: getnameinfo failed");
2323 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2325 error("socket: %.100s", strerror(errno));
2328 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2329 fatal("connect_to: F_SETFL: %s", strerror(errno));
2330 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2331 errno != EINPROGRESS) {
2332 error("connect_to %.100s port %s: %.100s", ntop, strport,
2335 continue; /* fail -- try next */
2337 break; /* success */
2340 freeaddrinfo(aitop);
2342 error("connect_to %.100s port %d: failed.", host, port);
2350 channel_connect_by_listen_address(u_short listen_port)
2354 for (i = 0; i < num_permitted_opens; i++)
2355 if (permitted_opens[i].listen_port == listen_port)
2357 permitted_opens[i].host_to_connect,
2358 permitted_opens[i].port_to_connect);
2359 error("WARNING: Server requests forwarding for unknown listen_port %d",
2364 /* Check if connecting to that port is permitted and connect. */
2366 channel_connect_to(const char *host, u_short port)
2370 permit = all_opens_permitted;
2372 for (i = 0; i < num_permitted_opens; i++)
2373 if (permitted_opens[i].port_to_connect == port &&
2374 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2379 log("Received request to connect to host %.100s port %d, "
2380 "but the request was denied.", host, port);
2383 return connect_to(host, port);
2386 /* -- X11 forwarding */
2389 * Creates an internet domain socket for listening for X11 connections.
2390 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2394 x11_create_display_inet(int screen_number, int x11_display_offset)
2396 int display_number, sock;
2398 struct addrinfo hints, *ai, *aitop;
2399 char strport[NI_MAXSERV];
2400 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2402 char hostname[MAXHOSTNAMELEN];
2404 for (display_number = x11_display_offset;
2405 display_number < MAX_DISPLAYS;
2407 port = 6000 + display_number;
2408 memset(&hints, 0, sizeof(hints));
2409 hints.ai_family = IPv4or6;
2410 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2411 hints.ai_socktype = SOCK_STREAM;
2412 snprintf(strport, sizeof strport, "%d", port);
2413 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2414 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2417 for (ai = aitop; ai; ai = ai->ai_next) {
2418 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2420 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2422 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2423 error("socket: %.100s", strerror(errno));
2426 debug("x11_create_display_inet: Socket family %d not supported",
2431 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2432 debug("bind port %d: %.100s", port, strerror(errno));
2433 shutdown(sock, SHUT_RDWR);
2439 for (n = 0; n < num_socks; n++) {
2440 shutdown(socks[n], SHUT_RDWR);
2446 socks[num_socks++] = sock;
2447 #ifndef DONT_TRY_OTHER_AF
2448 if (num_socks == NUM_SOCKS)
2454 freeaddrinfo(aitop);
2458 if (display_number >= MAX_DISPLAYS) {
2459 error("Failed to allocate internet-domain X11 display socket.");
2462 /* Start listening for connections on the socket. */
2463 for (n = 0; n < num_socks; n++) {
2465 if (listen(sock, 5) < 0) {
2466 error("listen: %.100s", strerror(errno));
2467 shutdown(sock, SHUT_RDWR);
2473 /* Set up a suitable value for the DISPLAY variable. */
2474 if (gethostname(hostname, sizeof(hostname)) < 0)
2475 fatal("gethostname: %.100s", strerror(errno));
2477 #ifdef IPADDR_IN_DISPLAY
2479 * HPUX detects the local hostname in the DISPLAY variable and tries
2480 * to set up a shared memory connection to the server, which it
2481 * incorrectly supposes to be local.
2483 * The workaround - as used in later $$H and other programs - is
2484 * is to set display to the host's IP address.
2488 struct in_addr my_addr;
2490 he = gethostbyname(hostname);
2492 error("[X11-broken-fwd-hostname-workaround] Could not get "
2493 "IP address for hostname %s.", hostname);
2495 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2496 "Could not get IP address for hostname %s.", hostname);
2498 shutdown(sock, SHUT_RDWR);
2504 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2506 /* Set DISPLAY to <ip address>:screen.display */
2507 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2508 display_number, screen_number);
2510 #else /* IPADDR_IN_DISPLAY */
2511 /* Just set DISPLAY to hostname:screen.display */
2512 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2513 display_number, screen_number);
2514 #endif /* IPADDR_IN_DISPLAY */
2516 /* Allocate a channel for each socket. */
2517 for (n = 0; n < num_socks; n++) {
2519 (void) channel_new("x11 listener",
2520 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2521 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2522 0, xstrdup("X11 inet listener"), 1);
2525 /* Return a suitable value for the DISPLAY environment variable. */
2526 return xstrdup(display);
2530 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2534 connect_local_xsocket(u_int dnr)
2536 static const char *const x_sockets[] = {
2538 "/var/X/.X11-unix/X" "%u",
2539 "/usr/spool/sockets/X11/" "%u",
2543 struct sockaddr_un addr;
2544 const char *const * path;
2546 for (path = x_sockets; *path; ++path) {
2547 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2549 error("socket: %.100s", strerror(errno));
2550 memset(&addr, 0, sizeof(addr));
2551 addr.sun_family = AF_UNIX;
2552 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2553 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2557 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2562 x11_connect_display(void)
2564 int display_number, sock = 0;
2565 const char *display;
2566 char buf[1024], *cp;
2567 struct addrinfo hints, *ai, *aitop;
2568 char strport[NI_MAXSERV];
2571 /* Try to open a socket for the local X server. */
2572 display = getenv("DISPLAY");
2574 error("DISPLAY not set.");
2578 * Now we decode the value of the DISPLAY variable and make a
2579 * connection to the real X server.
2583 * Check if it is a unix domain socket. Unix domain displays are in
2584 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2586 if (strncmp(display, "unix:", 5) == 0 ||
2587 display[0] == ':') {
2588 /* Connect to the unix domain socket. */
2589 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2590 error("Could not parse display number from DISPLAY: %.100s",
2594 /* Create a socket. */
2595 sock = connect_local_xsocket(display_number);
2599 /* OK, we now have a connection to the display. */
2603 * Connect to an inet socket. The DISPLAY value is supposedly
2604 * hostname:d[.s], where hostname may also be numeric IP address.
2606 strncpy(buf, display, sizeof(buf));
2607 buf[sizeof(buf) - 1] = 0;
2608 cp = strchr(buf, ':');
2610 error("Could not find ':' in DISPLAY: %.100s", display);
2614 /* buf now contains the host name. But first we parse the display number. */
2615 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2616 error("Could not parse display number from DISPLAY: %.100s",
2621 /* Look up the host address */
2622 memset(&hints, 0, sizeof(hints));
2623 hints.ai_family = IPv4or6;
2624 hints.ai_socktype = SOCK_STREAM;
2625 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2626 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2627 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2630 for (ai = aitop; ai; ai = ai->ai_next) {
2631 /* Create a socket. */
2632 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2634 debug("socket: %.100s", strerror(errno));
2637 /* Connect it to the display. */
2638 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2639 debug("connect %.100s port %d: %.100s", buf,
2640 6000 + display_number, strerror(errno));
2647 freeaddrinfo(aitop);
2649 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2657 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2658 * the remote channel number. We should do whatever we want, and respond
2659 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2663 x11_input_open(int type, int plen, void *ctxt)
2666 int remote_id, sock = 0;
2669 debug("Received X11 open request.");
2671 remote_id = packet_get_int();
2673 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2674 remote_host = packet_get_string(NULL);
2676 remote_host = xstrdup("unknown (remote did not supply name)");
2680 /* Obtain a connection to the real X display. */
2681 sock = x11_connect_display();
2683 /* Allocate a channel for this connection. */
2684 c = channel_new("connected x11 socket",
2685 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2688 error("x11_input_open: channel_new failed");
2691 c->remote_id = remote_id;
2696 /* Send refusal to the remote host. */
2697 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2698 packet_put_int(remote_id);
2700 /* Send a confirmation to the remote host. */
2701 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2702 packet_put_int(remote_id);
2703 packet_put_int(c->self);
2708 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2710 deny_input_open(int type, int plen, void *ctxt)
2712 int rchan = packet_get_int();
2714 case SSH_SMSG_AGENT_OPEN:
2715 error("Warning: ssh server tried agent forwarding.");
2717 case SSH_SMSG_X11_OPEN:
2718 error("Warning: ssh server tried X11 forwarding.");
2721 error("deny_input_open: type %d plen %d", type, plen);
2724 error("Warning: this is probably a break in attempt by a malicious server.");
2725 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2726 packet_put_int(rchan);
2731 * Requests forwarding of X11 connections, generates fake authentication
2732 * data, and enables authentication spoofing.
2733 * This should be called in the client only.
2736 x11_request_forwarding_with_spoofing(int client_session_id,
2737 const char *proto, const char *data)
2739 u_int data_len = (u_int) strlen(data) / 2;
2740 u_int i, value, len;
2746 cp = getenv("DISPLAY");
2748 cp = strchr(cp, ':');
2750 cp = strchr(cp, '.');
2752 screen_number = atoi(cp + 1);
2756 /* Save protocol name. */
2757 x11_saved_proto = xstrdup(proto);
2760 * Extract real authentication data and generate fake data of the
2763 x11_saved_data = xmalloc(data_len);
2764 x11_fake_data = xmalloc(data_len);
2765 for (i = 0; i < data_len; i++) {
2766 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2767 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2769 rand = arc4random();
2770 x11_saved_data[i] = value;
2771 x11_fake_data[i] = rand & 0xff;
2774 x11_saved_data_len = data_len;
2775 x11_fake_data_len = data_len;
2777 /* Convert the fake data into hex. */
2778 len = 2 * data_len + 1;
2779 new_data = xmalloc(len);
2780 for (i = 0; i < data_len; i++)
2781 snprintf(new_data + 2 * i, len - 2 * i,
2782 "%02x", (u_char) x11_fake_data[i]);
2784 /* Send the request packet. */
2786 channel_request_start(client_session_id, "x11-req", 0);
2787 packet_put_char(0); /* XXX bool single connection */
2789 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2791 packet_put_cstring(proto);
2792 packet_put_cstring(new_data);
2793 packet_put_int(screen_number);
2795 packet_write_wait();
2800 /* -- agent forwarding */
2802 /* Sends a message to the server to request authentication fd forwarding. */
2805 auth_request_forwarding()
2807 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2809 packet_write_wait();
2813 * Returns the name of the forwarded authentication socket. Returns NULL if
2814 * there is no forwarded authentication socket. The returned value points to
2819 auth_get_socket_name()
2821 return auth_sock_name;
2824 /* removes the agent forwarding socket */
2827 auth_sock_cleanup_proc(void *_pw)
2829 struct passwd *pw = _pw;
2831 if (auth_sock_name) {
2832 temporarily_use_uid(pw);
2833 unlink(auth_sock_name);
2834 rmdir(auth_sock_dir);
2835 auth_sock_name = NULL;
2841 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2842 * This starts forwarding authentication requests.
2846 auth_input_request_forwarding(struct passwd * pw)
2850 struct sockaddr_un sunaddr;
2852 if (auth_get_socket_name() != NULL) {
2853 error("authentication forwarding requested twice.");
2857 /* Temporarily drop privileged uid for mkdir/bind. */
2858 temporarily_use_uid(pw);
2860 /* Allocate a buffer for the socket name, and format the name. */
2861 auth_sock_name = xmalloc(MAXPATHLEN);
2862 auth_sock_dir = xmalloc(MAXPATHLEN);
2863 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2865 /* Create private directory for socket */
2866 if (mkdtemp(auth_sock_dir) == NULL) {
2867 packet_send_debug("Agent forwarding disabled: "
2868 "mkdtemp() failed: %.100s", strerror(errno));
2870 xfree(auth_sock_name);
2871 xfree(auth_sock_dir);
2872 auth_sock_name = NULL;
2873 auth_sock_dir = NULL;
2876 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2877 auth_sock_dir, (int) getpid());
2879 /* delete agent socket on fatal() */
2880 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2882 /* Create the socket. */
2883 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2885 packet_disconnect("socket: %.100s", strerror(errno));
2887 /* Bind it to the name. */
2888 memset(&sunaddr, 0, sizeof(sunaddr));
2889 sunaddr.sun_family = AF_UNIX;
2890 strncpy(sunaddr.sun_path, auth_sock_name,
2891 sizeof(sunaddr.sun_path));
2893 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2894 packet_disconnect("bind: %.100s", strerror(errno));
2896 /* Restore the privileged uid. */
2899 /* Start listening on the socket. */
2900 if (listen(sock, 5) < 0)
2901 packet_disconnect("listen: %.100s", strerror(errno));
2903 /* Allocate a channel for the authentication agent socket. */
2904 nc = channel_new("auth socket",
2905 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2906 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2907 0, xstrdup("auth socket"), 1);
2909 error("auth_input_request_forwarding: channel_new failed");
2910 auth_sock_cleanup_proc(pw);
2911 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2915 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2919 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2922 auth_input_open_request(int type, int plen, void *ctxt)
2925 int remote_id, sock;
2928 packet_integrity_check(plen, 4, type);
2930 /* Read the remote channel number from the message. */
2931 remote_id = packet_get_int();
2934 * Get a connection to the local authentication agent (this may again
2937 sock = ssh_get_authentication_socket();
2940 * If we could not connect the agent, send an error message back to
2941 * the server. This should never happen unless the agent dies,
2942 * because authentication forwarding is only enabled if we have an
2946 name = xstrdup("authentication agent connection");
2947 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2948 -1, 0, 0, 0, name, 1);
2950 error("auth_input_open_request: channel_new failed");
2954 c->remote_id = remote_id;
2959 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2960 packet_put_int(remote_id);
2962 /* Send a confirmation to the remote host. */
2963 debug("Forwarding authentication connection.");
2964 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2965 packet_put_int(remote_id);
2966 packet_put_int(c->self);