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, 2002 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 1.180 2002/07/04 08:12:15 deraadt Exp $");
56 #include "pathnames.h"
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 /* AF_UNSPEC or AF_INET or AF_INET6 */
132 static int IPv4or6 = AF_UNSPEC;
135 static void port_open_helper(Channel *c, char *rtype);
137 /* -- channel core */
140 channel_lookup(int id)
144 if (id < 0 || id >= channels_alloc) {
145 log("channel_lookup: %d: bad id", id);
150 log("channel_lookup: %d: bad id: channel free", id);
157 * Register filedescriptors for a channel, used when allocating a channel or
158 * when the channel consumer/producer is ready, e.g. shell exec'd
162 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
163 int extusage, int nonblock)
165 /* Update the maximum file descriptor value. */
166 channel_max_fd = MAX(channel_max_fd, rfd);
167 channel_max_fd = MAX(channel_max_fd, wfd);
168 channel_max_fd = MAX(channel_max_fd, efd);
170 /* XXX set close-on-exec -markus */
174 c->sock = (rfd == wfd) ? rfd : -1;
176 c->extended_usage = extusage;
178 /* XXX ugly hack: nonblock is only set by the server */
179 if (nonblock && isatty(c->rfd)) {
180 debug("channel %d: rfd %d isatty", c->self, c->rfd);
182 if (!isatty(c->wfd)) {
183 error("channel %d: wfd %d is not a tty?",
190 /* enable nonblocking mode */
202 * Allocate a new channel object and set its type and socket. This will cause
203 * remote_name to be freed.
207 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
208 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
213 /* Do initial allocation if this is the first call. */
214 if (channels_alloc == 0) {
216 channels = xmalloc(channels_alloc * sizeof(Channel *));
217 for (i = 0; i < channels_alloc; i++)
219 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
221 /* Try to find a free slot where to put the new channel. */
222 for (found = -1, i = 0; i < channels_alloc; i++)
223 if (channels[i] == NULL) {
224 /* Found a free slot. */
229 /* There are no free slots. Take last+1 slot and expand the array. */
230 found = channels_alloc;
231 channels_alloc += 10;
232 if (channels_alloc > 10000)
233 fatal("channel_new: internal error: channels_alloc %d "
234 "too big.", channels_alloc);
235 debug2("channel: expanding %d", channels_alloc);
236 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
237 for (i = found; i < channels_alloc; i++)
240 /* Initialize and return new channel. */
241 c = channels[found] = xmalloc(sizeof(Channel));
242 memset(c, 0, sizeof(Channel));
243 buffer_init(&c->input);
244 buffer_init(&c->output);
245 buffer_init(&c->extended);
246 c->ostate = CHAN_OUTPUT_OPEN;
247 c->istate = CHAN_INPUT_OPEN;
249 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
253 c->local_window = window;
254 c->local_window_max = window;
255 c->local_consumed = 0;
256 c->local_maxpacket = maxpack;
258 c->remote_name = remote_name;
259 c->remote_window = 0;
260 c->remote_maxpacket = 0;
262 c->single_connection = 0;
263 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);
334 shutdown(c->sock, SHUT_RDWR);
335 channel_close_fds(c);
336 buffer_free(&c->input);
337 buffer_free(&c->output);
338 buffer_free(&c->extended);
339 if (c->remote_name) {
340 xfree(c->remote_name);
341 c->remote_name = NULL;
343 channels[c->self] = NULL;
348 channel_free_all(void)
352 for (i = 0; i < channels_alloc; i++)
353 if (channels[i] != NULL)
354 channel_free(channels[i]);
358 * Closes the sockets/fds of all channels. This is used to close extra file
359 * descriptors after a fork.
363 channel_close_all(void)
367 for (i = 0; i < channels_alloc; i++)
368 if (channels[i] != NULL)
369 channel_close_fds(channels[i]);
373 * Stop listening to channels.
377 channel_stop_listening(void)
382 for (i = 0; i < channels_alloc; i++) {
386 case SSH_CHANNEL_AUTH_SOCKET:
387 case SSH_CHANNEL_PORT_LISTENER:
388 case SSH_CHANNEL_RPORT_LISTENER:
389 case SSH_CHANNEL_X11_LISTENER:
390 channel_close_fd(&c->sock);
399 * Returns true if no channel has too much buffered data, and false if one or
400 * more channel is overfull.
404 channel_not_very_much_buffered_data(void)
409 for (i = 0; i < channels_alloc; i++) {
411 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
414 buffer_len(&c->input) > packet_get_maxsize()) {
415 debug("channel %d: big input buffer %d",
416 c->self, buffer_len(&c->input));
420 if (buffer_len(&c->output) > packet_get_maxsize()) {
421 debug("channel %d: big output buffer %d > %d",
422 c->self, buffer_len(&c->output),
423 packet_get_maxsize());
431 /* Returns true if any channel is still open. */
434 channel_still_open(void)
439 for (i = 0; i < channels_alloc; i++) {
444 case SSH_CHANNEL_X11_LISTENER:
445 case SSH_CHANNEL_PORT_LISTENER:
446 case SSH_CHANNEL_RPORT_LISTENER:
447 case SSH_CHANNEL_CLOSED:
448 case SSH_CHANNEL_AUTH_SOCKET:
449 case SSH_CHANNEL_DYNAMIC:
450 case SSH_CHANNEL_CONNECTING:
451 case SSH_CHANNEL_ZOMBIE:
453 case SSH_CHANNEL_LARVAL:
455 fatal("cannot happen: SSH_CHANNEL_LARVAL");
457 case SSH_CHANNEL_OPENING:
458 case SSH_CHANNEL_OPEN:
459 case SSH_CHANNEL_X11_OPEN:
461 case SSH_CHANNEL_INPUT_DRAINING:
462 case SSH_CHANNEL_OUTPUT_DRAINING:
464 fatal("cannot happen: OUT_DRAIN");
467 fatal("channel_still_open: bad channel type %d", c->type);
474 /* Returns the id of an open channel suitable for keepaliving */
477 channel_find_open(void)
482 for (i = 0; i < channels_alloc; i++) {
487 case SSH_CHANNEL_CLOSED:
488 case SSH_CHANNEL_DYNAMIC:
489 case SSH_CHANNEL_X11_LISTENER:
490 case SSH_CHANNEL_PORT_LISTENER:
491 case SSH_CHANNEL_RPORT_LISTENER:
492 case SSH_CHANNEL_OPENING:
493 case SSH_CHANNEL_CONNECTING:
494 case SSH_CHANNEL_ZOMBIE:
496 case SSH_CHANNEL_LARVAL:
497 case SSH_CHANNEL_AUTH_SOCKET:
498 case SSH_CHANNEL_OPEN:
499 case SSH_CHANNEL_X11_OPEN:
501 case SSH_CHANNEL_INPUT_DRAINING:
502 case SSH_CHANNEL_OUTPUT_DRAINING:
504 fatal("cannot happen: OUT_DRAIN");
507 fatal("channel_find_open: bad channel type %d", c->type);
516 * Returns a message describing the currently open forwarded connections,
517 * suitable for sending to the client. The message contains crlf pairs for
522 channel_open_message(void)
529 buffer_init(&buffer);
530 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
531 buffer_append(&buffer, buf, strlen(buf));
532 for (i = 0; i < channels_alloc; i++) {
537 case SSH_CHANNEL_X11_LISTENER:
538 case SSH_CHANNEL_PORT_LISTENER:
539 case SSH_CHANNEL_RPORT_LISTENER:
540 case SSH_CHANNEL_CLOSED:
541 case SSH_CHANNEL_AUTH_SOCKET:
542 case SSH_CHANNEL_ZOMBIE:
544 case SSH_CHANNEL_LARVAL:
545 case SSH_CHANNEL_OPENING:
546 case SSH_CHANNEL_CONNECTING:
547 case SSH_CHANNEL_DYNAMIC:
548 case SSH_CHANNEL_OPEN:
549 case SSH_CHANNEL_X11_OPEN:
550 case SSH_CHANNEL_INPUT_DRAINING:
551 case SSH_CHANNEL_OUTPUT_DRAINING:
552 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
553 c->self, c->remote_name,
554 c->type, c->remote_id,
555 c->istate, buffer_len(&c->input),
556 c->ostate, buffer_len(&c->output),
558 buffer_append(&buffer, buf, strlen(buf));
561 fatal("channel_open_message: bad channel type %d", c->type);
565 buffer_append(&buffer, "\0", 1);
566 cp = xstrdup(buffer_ptr(&buffer));
567 buffer_free(&buffer);
572 channel_send_open(int id)
574 Channel *c = channel_lookup(id);
577 log("channel_send_open: %d: bad id", id);
580 debug("send channel open %d", id);
581 packet_start(SSH2_MSG_CHANNEL_OPEN);
582 packet_put_cstring(c->ctype);
583 packet_put_int(c->self);
584 packet_put_int(c->local_window);
585 packet_put_int(c->local_maxpacket);
590 channel_request_start(int local_id, char *service, int wantconfirm)
592 Channel *c = channel_lookup(local_id);
595 log("channel_request_start: %d: unknown channel id", local_id);
598 debug("channel request %d: %s", local_id, service) ;
599 packet_start(SSH2_MSG_CHANNEL_REQUEST);
600 packet_put_int(c->remote_id);
601 packet_put_cstring(service);
602 packet_put_char(wantconfirm);
605 channel_register_confirm(int id, channel_callback_fn *fn)
607 Channel *c = channel_lookup(id);
610 log("channel_register_comfirm: %d: bad id", id);
616 channel_register_cleanup(int id, channel_callback_fn *fn)
618 Channel *c = channel_lookup(id);
621 log("channel_register_cleanup: %d: bad id", id);
627 channel_cancel_cleanup(int id)
629 Channel *c = channel_lookup(id);
632 log("channel_cancel_cleanup: %d: bad id", id);
635 c->detach_user = NULL;
638 channel_register_filter(int id, channel_filter_fn *fn)
640 Channel *c = channel_lookup(id);
643 log("channel_register_filter: %d: bad id", id);
646 c->input_filter = fn;
650 channel_set_fds(int id, int rfd, int wfd, int efd,
651 int extusage, int nonblock, u_int window_max)
653 Channel *c = channel_lookup(id);
655 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
656 fatal("channel_activate for non-larval channel %d.", id);
657 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
658 c->type = SSH_CHANNEL_OPEN;
659 c->local_window = c->local_window_max = window_max;
660 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
661 packet_put_int(c->remote_id);
662 packet_put_int(c->local_window);
667 * 'channel_pre*' are called just before select() to add any bits relevant to
668 * channels in the select bitmasks.
671 * 'channel_post*': perform any appropriate operations for channels which
672 * have events pending.
674 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
675 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
676 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
679 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
681 FD_SET(c->sock, readset);
685 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
687 debug3("channel %d: waiting for connection", c->self);
688 FD_SET(c->sock, writeset);
692 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
694 if (buffer_len(&c->input) < packet_get_maxsize())
695 FD_SET(c->sock, readset);
696 if (buffer_len(&c->output) > 0)
697 FD_SET(c->sock, writeset);
701 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
703 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
705 if (c->istate == CHAN_INPUT_OPEN &&
707 buffer_len(&c->input) < limit)
708 FD_SET(c->rfd, readset);
709 if (c->ostate == CHAN_OUTPUT_OPEN ||
710 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
711 if (buffer_len(&c->output) > 0) {
712 FD_SET(c->wfd, writeset);
713 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
714 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
715 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
716 c->self, c->efd, buffer_len(&c->extended));
721 /** XXX check close conditions, too */
722 if (compat20 && c->efd != -1) {
723 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
724 buffer_len(&c->extended) > 0)
725 FD_SET(c->efd, writeset);
726 else if (!(c->flags & CHAN_EOF_SENT) &&
727 c->extended_usage == CHAN_EXTENDED_READ &&
728 buffer_len(&c->extended) < c->remote_window)
729 FD_SET(c->efd, readset);
734 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
736 if (buffer_len(&c->input) == 0) {
737 packet_start(SSH_MSG_CHANNEL_CLOSE);
738 packet_put_int(c->remote_id);
740 c->type = SSH_CHANNEL_CLOSED;
741 debug("channel %d: closing after input drain.", c->self);
746 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
748 if (buffer_len(&c->output) == 0)
751 FD_SET(c->sock, writeset);
755 * This is a special state for X11 authentication spoofing. An opened X11
756 * connection (when authentication spoofing is being done) remains in this
757 * state until the first packet has been completely read. The authentication
758 * data in that packet is then substituted by the real data if it matches the
759 * fake data, and the channel is put into normal mode.
760 * XXX All this happens at the client side.
761 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
764 x11_open_helper(Buffer *b)
767 u_int proto_len, data_len;
769 /* Check if the fixed size part of the packet is in buffer. */
770 if (buffer_len(b) < 12)
773 /* Parse the lengths of variable-length fields. */
775 if (ucp[0] == 0x42) { /* Byte order MSB first. */
776 proto_len = 256 * ucp[6] + ucp[7];
777 data_len = 256 * ucp[8] + ucp[9];
778 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
779 proto_len = ucp[6] + 256 * ucp[7];
780 data_len = ucp[8] + 256 * ucp[9];
782 debug("Initial X11 packet contains bad byte order byte: 0x%x",
787 /* Check if the whole packet is in buffer. */
789 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
792 /* Check if authentication protocol matches. */
793 if (proto_len != strlen(x11_saved_proto) ||
794 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
795 debug("X11 connection uses different authentication protocol.");
798 /* Check if authentication data matches our fake data. */
799 if (data_len != x11_fake_data_len ||
800 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
801 x11_fake_data, x11_fake_data_len) != 0) {
802 debug("X11 auth data does not match fake data.");
805 /* Check fake data length */
806 if (x11_fake_data_len != x11_saved_data_len) {
807 error("X11 fake_data_len %d != saved_data_len %d",
808 x11_fake_data_len, x11_saved_data_len);
812 * Received authentication protocol and data match
813 * our fake data. Substitute the fake data with real
816 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
817 x11_saved_data, x11_saved_data_len);
822 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
824 int ret = x11_open_helper(&c->output);
827 /* Start normal processing for the channel. */
828 c->type = SSH_CHANNEL_OPEN;
829 channel_pre_open_13(c, readset, writeset);
830 } else if (ret == -1) {
832 * We have received an X11 connection that has bad
833 * authentication information.
835 log("X11 connection rejected because of wrong authentication.");
836 buffer_clear(&c->input);
837 buffer_clear(&c->output);
838 channel_close_fd(&c->sock);
840 c->type = SSH_CHANNEL_CLOSED;
841 packet_start(SSH_MSG_CHANNEL_CLOSE);
842 packet_put_int(c->remote_id);
848 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
850 int ret = x11_open_helper(&c->output);
852 /* c->force_drain = 1; */
855 c->type = SSH_CHANNEL_OPEN;
856 channel_pre_open(c, readset, writeset);
857 } else if (ret == -1) {
858 log("X11 connection rejected because of wrong authentication.");
859 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
861 buffer_clear(&c->input);
863 buffer_clear(&c->output);
864 /* for proto v1, the peer will send an IEOF */
866 chan_write_failed(c);
868 c->type = SSH_CHANNEL_OPEN;
869 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
873 /* try to decode a socks4 header */
875 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
878 int len, have, i, found;
884 struct in_addr dest_addr;
887 debug2("channel %d: decode socks4", c->self);
889 have = buffer_len(&c->input);
890 len = sizeof(s4_req);
893 p = buffer_ptr(&c->input);
894 for (found = 0, i = len; i < have; i++) {
900 /* the peer is probably sending garbage */
901 debug("channel %d: decode socks4: too long",
908 buffer_get(&c->input, (char *)&s4_req.version, 1);
909 buffer_get(&c->input, (char *)&s4_req.command, 1);
910 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
911 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
912 have = buffer_len(&c->input);
913 p = buffer_ptr(&c->input);
915 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
917 fatal("channel %d: decode socks4: len %d > have %d",
919 strlcpy(username, p, sizeof(username));
920 buffer_consume(&c->input, len);
921 buffer_consume(&c->input, 1); /* trailing '\0' */
923 host = inet_ntoa(s4_req.dest_addr);
924 strlcpy(c->path, host, sizeof(c->path));
925 c->host_port = ntohs(s4_req.dest_port);
927 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
928 c->self, host, c->host_port, s4_req.command);
930 if (s4_req.command != 1) {
931 debug("channel %d: cannot handle: socks4 cn %d",
932 c->self, s4_req.command);
935 s4_rsp.version = 0; /* vn: 0 for reply */
936 s4_rsp.command = 90; /* cd: req granted */
937 s4_rsp.dest_port = 0; /* ignored */
938 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
939 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
943 /* dynamic port forwarding */
945 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
950 have = buffer_len(&c->input);
952 debug2("channel %d: pre_dynamic: have %d", c->self, have);
953 /* buffer_dump(&c->input); */
954 /* check if the fixed size part of the packet is in buffer. */
957 FD_SET(c->sock, readset);
960 /* try to guess the protocol */
961 p = buffer_ptr(&c->input);
964 ret = channel_decode_socks4(c, readset, writeset);
972 } else if (ret == 0) {
973 debug2("channel %d: pre_dynamic: need more", c->self);
975 FD_SET(c->sock, readset);
977 /* switch to the next state */
978 c->type = SSH_CHANNEL_OPENING;
979 port_open_helper(c, "direct-tcpip");
983 /* This is our fake X11 server socket. */
985 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
988 struct sockaddr addr;
991 char buf[16384], *remote_ipaddr;
994 if (FD_ISSET(c->sock, readset)) {
995 debug("X11 connection requested.");
996 addrlen = sizeof(addr);
997 newsock = accept(c->sock, &addr, &addrlen);
998 if (c->single_connection) {
999 debug("single_connection: closing X11 listener.");
1000 channel_close_fd(&c->sock);
1004 error("accept: %.100s", strerror(errno));
1007 set_nodelay(newsock);
1008 remote_ipaddr = get_peer_ipaddr(newsock);
1009 remote_port = get_peer_port(newsock);
1010 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1011 remote_ipaddr, remote_port);
1013 nc = channel_new("accepted x11 socket",
1014 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1015 c->local_window_max, c->local_maxpacket,
1016 0, xstrdup(buf), 1);
1018 packet_start(SSH2_MSG_CHANNEL_OPEN);
1019 packet_put_cstring("x11");
1020 packet_put_int(nc->self);
1021 packet_put_int(nc->local_window_max);
1022 packet_put_int(nc->local_maxpacket);
1023 /* originator ipaddr and port */
1024 packet_put_cstring(remote_ipaddr);
1025 if (datafellows & SSH_BUG_X11FWD) {
1026 debug("ssh2 x11 bug compat mode");
1028 packet_put_int(remote_port);
1032 packet_start(SSH_SMSG_X11_OPEN);
1033 packet_put_int(nc->self);
1034 if (packet_get_protocol_flags() &
1035 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1036 packet_put_cstring(buf);
1039 xfree(remote_ipaddr);
1044 port_open_helper(Channel *c, char *rtype)
1048 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1049 u_short remote_port = get_peer_port(c->sock);
1051 direct = (strcmp(rtype, "direct-tcpip") == 0);
1053 snprintf(buf, sizeof buf,
1054 "%s: listening port %d for %.100s port %d, "
1055 "connect from %.200s port %d",
1056 rtype, c->listening_port, c->path, c->host_port,
1057 remote_ipaddr, remote_port);
1059 xfree(c->remote_name);
1060 c->remote_name = xstrdup(buf);
1063 packet_start(SSH2_MSG_CHANNEL_OPEN);
1064 packet_put_cstring(rtype);
1065 packet_put_int(c->self);
1066 packet_put_int(c->local_window_max);
1067 packet_put_int(c->local_maxpacket);
1069 /* target host, port */
1070 packet_put_cstring(c->path);
1071 packet_put_int(c->host_port);
1073 /* listen address, port */
1074 packet_put_cstring(c->path);
1075 packet_put_int(c->listening_port);
1077 /* originator host and port */
1078 packet_put_cstring(remote_ipaddr);
1079 packet_put_int(remote_port);
1082 packet_start(SSH_MSG_PORT_OPEN);
1083 packet_put_int(c->self);
1084 packet_put_cstring(c->path);
1085 packet_put_int(c->host_port);
1086 if (packet_get_protocol_flags() &
1087 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1088 packet_put_cstring(c->remote_name);
1091 xfree(remote_ipaddr);
1095 * This socket is listening for connections to a forwarded TCP/IP port.
1098 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1101 struct sockaddr addr;
1102 int newsock, nextstate;
1106 if (FD_ISSET(c->sock, readset)) {
1107 debug("Connection to port %d forwarding "
1108 "to %.100s port %d requested.",
1109 c->listening_port, c->path, c->host_port);
1111 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1112 nextstate = SSH_CHANNEL_OPENING;
1113 rtype = "forwarded-tcpip";
1115 if (c->host_port == 0) {
1116 nextstate = SSH_CHANNEL_DYNAMIC;
1117 rtype = "dynamic-tcpip";
1119 nextstate = SSH_CHANNEL_OPENING;
1120 rtype = "direct-tcpip";
1124 addrlen = sizeof(addr);
1125 newsock = accept(c->sock, &addr, &addrlen);
1127 error("accept: %.100s", strerror(errno));
1130 set_nodelay(newsock);
1131 nc = channel_new(rtype,
1132 nextstate, newsock, newsock, -1,
1133 c->local_window_max, c->local_maxpacket,
1134 0, xstrdup(rtype), 1);
1135 nc->listening_port = c->listening_port;
1136 nc->host_port = c->host_port;
1137 strlcpy(nc->path, c->path, sizeof(nc->path));
1139 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1141 * do not call the channel_post handler until
1142 * this flag has been reset by a pre-handler.
1143 * otherwise the FD_ISSET calls might overflow
1147 port_open_helper(nc, rtype);
1153 * This is the authentication agent socket listening for connections from
1157 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1162 struct sockaddr addr;
1165 if (FD_ISSET(c->sock, readset)) {
1166 addrlen = sizeof(addr);
1167 newsock = accept(c->sock, &addr, &addrlen);
1169 error("accept from auth socket: %.100s", strerror(errno));
1172 name = xstrdup("accepted auth socket");
1173 nc = channel_new("accepted auth socket",
1174 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1175 c->local_window_max, c->local_maxpacket,
1178 packet_start(SSH2_MSG_CHANNEL_OPEN);
1179 packet_put_cstring("auth-agent@openssh.com");
1180 packet_put_int(nc->self);
1181 packet_put_int(c->local_window_max);
1182 packet_put_int(c->local_maxpacket);
1184 packet_start(SSH_SMSG_AGENT_OPEN);
1185 packet_put_int(nc->self);
1192 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1195 socklen_t sz = sizeof(err);
1197 if (FD_ISSET(c->sock, writeset)) {
1198 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1200 error("getsockopt SO_ERROR failed");
1203 debug("channel %d: connected", c->self);
1204 c->type = SSH_CHANNEL_OPEN;
1206 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1207 packet_put_int(c->remote_id);
1208 packet_put_int(c->self);
1209 packet_put_int(c->local_window);
1210 packet_put_int(c->local_maxpacket);
1212 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1213 packet_put_int(c->remote_id);
1214 packet_put_int(c->self);
1217 debug("channel %d: not connected: %s",
1218 c->self, strerror(err));
1220 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1221 packet_put_int(c->remote_id);
1222 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1223 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1224 packet_put_cstring(strerror(err));
1225 packet_put_cstring("");
1228 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1229 packet_put_int(c->remote_id);
1238 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1244 FD_ISSET(c->rfd, readset)) {
1245 len = read(c->rfd, buf, sizeof(buf));
1246 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1249 debug("channel %d: read<=0 rfd %d len %d",
1250 c->self, c->rfd, len);
1251 if (c->type != SSH_CHANNEL_OPEN) {
1252 debug("channel %d: not open", c->self);
1255 } else if (compat13) {
1256 buffer_clear(&c->output);
1257 c->type = SSH_CHANNEL_INPUT_DRAINING;
1258 debug("channel %d: input draining.", c->self);
1260 chan_read_failed(c);
1264 if (c->input_filter != NULL) {
1265 if (c->input_filter(c, buf, len) == -1) {
1266 debug("channel %d: filter stops", c->self);
1267 chan_read_failed(c);
1270 buffer_append(&c->input, buf, len);
1276 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1283 /* Send buffered output data to the socket. */
1285 FD_ISSET(c->wfd, writeset) &&
1286 buffer_len(&c->output) > 0) {
1287 data = buffer_ptr(&c->output);
1288 dlen = buffer_len(&c->output);
1289 len = write(c->wfd, data, dlen);
1291 /* XXX: Later AIX versions can't push as much data to tty */
1292 if (compat20 && c->isatty && dlen >= 8*1024)
1295 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1298 if (c->type != SSH_CHANNEL_OPEN) {
1299 debug("channel %d: not open", c->self);
1302 } else if (compat13) {
1303 buffer_clear(&c->output);
1304 debug("channel %d: input draining.", c->self);
1305 c->type = SSH_CHANNEL_INPUT_DRAINING;
1307 chan_write_failed(c);
1311 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1312 if (tcgetattr(c->wfd, &tio) == 0 &&
1313 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1315 * Simulate echo to reduce the impact of
1316 * traffic analysis. We need to match the
1317 * size of a SSH2_MSG_CHANNEL_DATA message
1318 * (4 byte channel id + data)
1320 packet_send_ignore(4 + len);
1324 buffer_consume(&c->output, len);
1325 if (compat20 && len > 0) {
1326 c->local_consumed += len;
1332 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1337 /** XXX handle drain efd, too */
1339 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1340 FD_ISSET(c->efd, writeset) &&
1341 buffer_len(&c->extended) > 0) {
1342 len = write(c->efd, buffer_ptr(&c->extended),
1343 buffer_len(&c->extended));
1344 debug2("channel %d: written %d to efd %d",
1345 c->self, len, c->efd);
1346 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1349 debug2("channel %d: closing write-efd %d",
1351 channel_close_fd(&c->efd);
1353 buffer_consume(&c->extended, len);
1354 c->local_consumed += len;
1356 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1357 FD_ISSET(c->efd, readset)) {
1358 len = read(c->efd, buf, sizeof(buf));
1359 debug2("channel %d: read %d from efd %d",
1360 c->self, len, c->efd);
1361 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1364 debug2("channel %d: closing read-efd %d",
1366 channel_close_fd(&c->efd);
1368 buffer_append(&c->extended, buf, len);
1375 channel_check_window(Channel *c)
1377 if (c->type == SSH_CHANNEL_OPEN &&
1378 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1379 c->local_window < c->local_window_max/2 &&
1380 c->local_consumed > 0) {
1381 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1382 packet_put_int(c->remote_id);
1383 packet_put_int(c->local_consumed);
1385 debug2("channel %d: window %d sent adjust %d",
1386 c->self, c->local_window,
1388 c->local_window += c->local_consumed;
1389 c->local_consumed = 0;
1395 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1399 channel_handle_rfd(c, readset, writeset);
1400 channel_handle_wfd(c, readset, writeset);
1403 channel_handle_efd(c, readset, writeset);
1404 channel_check_window(c);
1408 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1412 /* Send buffered output data to the socket. */
1413 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1414 len = write(c->sock, buffer_ptr(&c->output),
1415 buffer_len(&c->output));
1417 buffer_clear(&c->output);
1419 buffer_consume(&c->output, len);
1424 channel_handler_init_20(void)
1426 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1427 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1428 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1429 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1430 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1431 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1432 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1433 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1435 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1436 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1437 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1438 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1439 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1440 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1441 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1445 channel_handler_init_13(void)
1447 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1448 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1449 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1450 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1451 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1452 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1453 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1454 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1455 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1457 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1458 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1459 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1460 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1461 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1462 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1463 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1467 channel_handler_init_15(void)
1469 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1470 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1471 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1472 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1473 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1474 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1475 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1477 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1478 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1479 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1480 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1481 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1482 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1486 channel_handler_init(void)
1490 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1491 channel_pre[i] = NULL;
1492 channel_post[i] = NULL;
1495 channel_handler_init_20();
1497 channel_handler_init_13();
1499 channel_handler_init_15();
1502 /* gc dead channels */
1504 channel_garbage_collect(Channel *c)
1508 if (c->detach_user != NULL) {
1509 if (!chan_is_dead(c, 0))
1511 debug("channel %d: gc: notify user", c->self);
1512 c->detach_user(c->self, NULL);
1513 /* if we still have a callback */
1514 if (c->detach_user != NULL)
1516 debug("channel %d: gc: user detached", c->self);
1518 if (!chan_is_dead(c, 1))
1520 debug("channel %d: garbage collecting", c->self);
1525 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1527 static int did_init = 0;
1532 channel_handler_init();
1535 for (i = 0; i < channels_alloc; i++) {
1539 if (ftab[c->type] != NULL)
1540 (*ftab[c->type])(c, readset, writeset);
1541 channel_garbage_collect(c);
1546 * Allocate/update select bitmasks and add any bits relevant to channels in
1550 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1551 int *nallocp, int rekeying)
1556 n = MAX(*maxfdp, channel_max_fd);
1558 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1559 /* perhaps check sz < nalloc/2 and shrink? */
1560 if (*readsetp == NULL || sz > *nallocp) {
1561 *readsetp = xrealloc(*readsetp, sz);
1562 *writesetp = xrealloc(*writesetp, sz);
1566 memset(*readsetp, 0, sz);
1567 memset(*writesetp, 0, sz);
1570 channel_handler(channel_pre, *readsetp, *writesetp);
1574 * After select, perform any appropriate operations for channels which have
1578 channel_after_select(fd_set * readset, fd_set * writeset)
1580 channel_handler(channel_post, readset, writeset);
1584 /* If there is data to send to the connection, enqueue some of it now. */
1587 channel_output_poll(void)
1593 for (i = 0; i < channels_alloc; i++) {
1599 * We are only interested in channels that can have buffered
1603 if (c->type != SSH_CHANNEL_OPEN &&
1604 c->type != SSH_CHANNEL_INPUT_DRAINING)
1607 if (c->type != SSH_CHANNEL_OPEN)
1611 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1612 /* XXX is this true? */
1613 debug3("channel %d: will not send data after close", c->self);
1617 /* Get the amount of buffered data for this channel. */
1618 if ((c->istate == CHAN_INPUT_OPEN ||
1619 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1620 (len = buffer_len(&c->input)) > 0) {
1622 * Send some data for the other side over the secure
1626 if (len > c->remote_window)
1627 len = c->remote_window;
1628 if (len > c->remote_maxpacket)
1629 len = c->remote_maxpacket;
1631 if (packet_is_interactive()) {
1635 /* Keep the packets at reasonable size. */
1636 if (len > packet_get_maxsize()/2)
1637 len = packet_get_maxsize()/2;
1641 packet_start(compat20 ?
1642 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1643 packet_put_int(c->remote_id);
1644 packet_put_string(buffer_ptr(&c->input), len);
1646 buffer_consume(&c->input, len);
1647 c->remote_window -= len;
1649 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1651 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1653 * input-buffer is empty and read-socket shutdown:
1654 * tell peer, that we will not send more data: send IEOF.
1655 * hack for extended data: delay EOF if EFD still in use.
1657 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1658 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1659 c->self, c->efd, buffer_len(&c->extended));
1663 /* Send extended data, i.e. stderr */
1665 !(c->flags & CHAN_EOF_SENT) &&
1666 c->remote_window > 0 &&
1667 (len = buffer_len(&c->extended)) > 0 &&
1668 c->extended_usage == CHAN_EXTENDED_READ) {
1669 debug2("channel %d: rwin %u elen %u euse %d",
1670 c->self, c->remote_window, buffer_len(&c->extended),
1672 if (len > c->remote_window)
1673 len = c->remote_window;
1674 if (len > c->remote_maxpacket)
1675 len = c->remote_maxpacket;
1676 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1677 packet_put_int(c->remote_id);
1678 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1679 packet_put_string(buffer_ptr(&c->extended), len);
1681 buffer_consume(&c->extended, len);
1682 c->remote_window -= len;
1683 debug2("channel %d: sent ext data %d", c->self, len);
1689 /* -- protocol input */
1692 channel_input_data(int type, u_int32_t seq, void *ctxt)
1699 /* Get the channel number and verify it. */
1700 id = packet_get_int();
1701 c = channel_lookup(id);
1703 packet_disconnect("Received data for nonexistent channel %d.", id);
1705 /* Ignore any data for non-open channels (might happen on close) */
1706 if (c->type != SSH_CHANNEL_OPEN &&
1707 c->type != SSH_CHANNEL_X11_OPEN)
1710 /* same for protocol 1.5 if output end is no longer open */
1711 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1715 data = packet_get_string(&data_len);
1718 if (data_len > c->local_maxpacket) {
1719 log("channel %d: rcvd big packet %d, maxpack %d",
1720 c->self, data_len, c->local_maxpacket);
1722 if (data_len > c->local_window) {
1723 log("channel %d: rcvd too much data %d, win %d",
1724 c->self, data_len, c->local_window);
1728 c->local_window -= data_len;
1731 buffer_append(&c->output, data, data_len);
1736 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1740 u_int data_len, tcode;
1743 /* Get the channel number and verify it. */
1744 id = packet_get_int();
1745 c = channel_lookup(id);
1748 packet_disconnect("Received extended_data for bad channel %d.", id);
1749 if (c->type != SSH_CHANNEL_OPEN) {
1750 log("channel %d: ext data for non open", id);
1753 if (c->flags & CHAN_EOF_RCVD) {
1754 if (datafellows & SSH_BUG_EXTEOF)
1755 debug("channel %d: accepting ext data after eof", id);
1757 packet_disconnect("Received extended_data after EOF "
1758 "on channel %d.", id);
1760 tcode = packet_get_int();
1762 c->extended_usage != CHAN_EXTENDED_WRITE ||
1763 tcode != SSH2_EXTENDED_DATA_STDERR) {
1764 log("channel %d: bad ext data", c->self);
1767 data = packet_get_string(&data_len);
1769 if (data_len > c->local_window) {
1770 log("channel %d: rcvd too much extended_data %d, win %d",
1771 c->self, data_len, c->local_window);
1775 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1776 c->local_window -= data_len;
1777 buffer_append(&c->extended, data, data_len);
1782 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1787 id = packet_get_int();
1789 c = channel_lookup(id);
1791 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1794 /* XXX force input close */
1795 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1796 debug("channel %d: FORCE input drain", c->self);
1797 c->istate = CHAN_INPUT_WAIT_DRAIN;
1798 if (buffer_len(&c->input) == 0)
1805 channel_input_close(int type, u_int32_t seq, void *ctxt)
1810 id = packet_get_int();
1812 c = channel_lookup(id);
1814 packet_disconnect("Received close for nonexistent channel %d.", id);
1817 * Send a confirmation that we have closed the channel and no more
1818 * data is coming for it.
1820 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1821 packet_put_int(c->remote_id);
1825 * If the channel is in closed state, we have sent a close request,
1826 * and the other side will eventually respond with a confirmation.
1827 * Thus, we cannot free the channel here, because then there would be
1828 * no-one to receive the confirmation. The channel gets freed when
1829 * the confirmation arrives.
1831 if (c->type != SSH_CHANNEL_CLOSED) {
1833 * Not a closed channel - mark it as draining, which will
1834 * cause it to be freed later.
1836 buffer_clear(&c->input);
1837 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1841 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1843 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
1845 int id = packet_get_int();
1846 Channel *c = channel_lookup(id);
1850 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1851 chan_rcvd_oclose(c);
1855 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
1857 int id = packet_get_int();
1858 Channel *c = channel_lookup(id);
1862 packet_disconnect("Received close confirmation for "
1863 "out-of-range channel %d.", id);
1864 if (c->type != SSH_CHANNEL_CLOSED)
1865 packet_disconnect("Received close confirmation for "
1866 "non-closed channel %d (type %d).", id, c->type);
1871 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
1876 id = packet_get_int();
1877 c = channel_lookup(id);
1879 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1880 packet_disconnect("Received open confirmation for "
1881 "non-opening channel %d.", id);
1882 remote_id = packet_get_int();
1883 /* Record the remote channel number and mark that the channel is now open. */
1884 c->remote_id = remote_id;
1885 c->type = SSH_CHANNEL_OPEN;
1888 c->remote_window = packet_get_int();
1889 c->remote_maxpacket = packet_get_int();
1891 debug2("callback start");
1892 c->confirm(c->self, NULL);
1893 debug2("callback done");
1895 debug("channel %d: open confirm rwindow %u rmax %u", c->self,
1896 c->remote_window, c->remote_maxpacket);
1902 reason2txt(int reason)
1905 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1906 return "administratively prohibited";
1907 case SSH2_OPEN_CONNECT_FAILED:
1908 return "connect failed";
1909 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1910 return "unknown channel type";
1911 case SSH2_OPEN_RESOURCE_SHORTAGE:
1912 return "resource shortage";
1914 return "unknown reason";
1918 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
1921 char *msg = NULL, *lang = NULL;
1924 id = packet_get_int();
1925 c = channel_lookup(id);
1927 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1928 packet_disconnect("Received open failure for "
1929 "non-opening channel %d.", id);
1931 reason = packet_get_int();
1932 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1933 msg = packet_get_string(NULL);
1934 lang = packet_get_string(NULL);
1936 log("channel %d: open failed: %s%s%s", id,
1937 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1944 /* Free the channel. This will also close the socket. */
1949 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
1958 /* Get the channel number and verify it. */
1959 id = packet_get_int();
1960 c = channel_lookup(id);
1962 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1963 log("Received window adjust for "
1964 "non-open channel %d.", id);
1967 adjust = packet_get_int();
1969 debug2("channel %d: rcvd adjust %u", id, adjust);
1970 c->remote_window += adjust;
1974 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
1978 char *host, *originator_string;
1979 int remote_id, sock = -1;
1981 remote_id = packet_get_int();
1982 host = packet_get_string(NULL);
1983 host_port = packet_get_int();
1985 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
1986 originator_string = packet_get_string(NULL);
1988 originator_string = xstrdup("unknown (remote did not supply name)");
1991 sock = channel_connect_to(host, host_port);
1993 c = channel_new("connected socket",
1994 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
1995 originator_string, 1);
1996 c->remote_id = remote_id;
1999 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2000 packet_put_int(remote_id);
2007 /* -- tcp forwarding */
2010 channel_set_af(int af)
2016 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2017 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2020 int success, sock, on = 1;
2021 struct addrinfo hints, *ai, *aitop;
2023 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2024 struct linger linger;
2027 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2028 listen_addr : host_to_connect;
2031 error("No forward host name.");
2034 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2035 error("Forward host name too long.");
2040 * getaddrinfo returns a loopback address if the hostname is
2041 * set to NULL and hints.ai_flags is not AI_PASSIVE
2043 memset(&hints, 0, sizeof(hints));
2044 hints.ai_family = IPv4or6;
2045 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2046 hints.ai_socktype = SOCK_STREAM;
2047 snprintf(strport, sizeof strport, "%d", listen_port);
2048 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2049 packet_disconnect("getaddrinfo: fatal error");
2051 for (ai = aitop; ai; ai = ai->ai_next) {
2052 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2054 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2055 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2056 error("channel_setup_fwd_listener: getnameinfo failed");
2059 /* Create a port to listen for the host. */
2060 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2062 /* this is no error since kernel may not support ipv6 */
2063 verbose("socket: %.100s", strerror(errno));
2067 * Set socket options. We would like the socket to disappear
2068 * as soon as it has been closed for whatever reason.
2070 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
2072 linger.l_linger = 5;
2073 setsockopt(sock, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
2074 debug("Local forwarding listening on %s port %s.", ntop, strport);
2076 /* Bind the socket to the address. */
2077 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2078 /* address can be in use ipv6 address is already bound */
2080 error("bind: %.100s", strerror(errno));
2082 verbose("bind: %.100s", strerror(errno));
2087 /* Start listening for connections on the socket. */
2088 if (listen(sock, 5) < 0) {
2089 error("listen: %.100s", strerror(errno));
2093 /* Allocate a channel number for the socket. */
2094 c = channel_new("port listener", type, sock, sock, -1,
2095 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2096 0, xstrdup("port listener"), 1);
2097 strlcpy(c->path, host, sizeof(c->path));
2098 c->host_port = port_to_connect;
2099 c->listening_port = listen_port;
2103 error("channel_setup_fwd_listener: cannot listen to port: %d",
2105 freeaddrinfo(aitop);
2109 /* protocol local port fwd, used by ssh (and sshd in v1) */
2111 channel_setup_local_fwd_listener(u_short listen_port,
2112 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2114 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2115 NULL, listen_port, host_to_connect, port_to_connect, gateway_ports);
2118 /* protocol v2 remote port fwd, used by sshd */
2120 channel_setup_remote_fwd_listener(const char *listen_address,
2121 u_short listen_port, int gateway_ports)
2123 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2124 listen_address, listen_port, NULL, 0, gateway_ports);
2128 * Initiate forwarding of connections to port "port" on remote host through
2129 * the secure channel to host:port from local side.
2133 channel_request_remote_forwarding(u_short listen_port,
2134 const char *host_to_connect, u_short port_to_connect)
2136 int type, success = 0;
2138 /* Record locally that connection to this host/port is permitted. */
2139 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2140 fatal("channel_request_remote_forwarding: too many forwards");
2142 /* Send the forward request to the remote side. */
2144 const char *address_to_bind = "0.0.0.0";
2145 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2146 packet_put_cstring("tcpip-forward");
2147 packet_put_char(1); /* boolean: want reply */
2148 packet_put_cstring(address_to_bind);
2149 packet_put_int(listen_port);
2151 packet_write_wait();
2152 /* Assume that server accepts the request */
2155 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2156 packet_put_int(listen_port);
2157 packet_put_cstring(host_to_connect);
2158 packet_put_int(port_to_connect);
2160 packet_write_wait();
2162 /* Wait for response from the remote side. */
2163 type = packet_read();
2165 case SSH_SMSG_SUCCESS:
2168 case SSH_SMSG_FAILURE:
2169 log("Warning: Server denied remote port forwarding.");
2172 /* Unknown packet */
2173 packet_disconnect("Protocol error for port forward request:"
2174 "received packet type %d.", type);
2178 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2179 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2180 permitted_opens[num_permitted_opens].listen_port = listen_port;
2181 num_permitted_opens++;
2186 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2187 * listening for the port, and sends back a success reply (or disconnect
2188 * message if there was an error). This never returns if there was an error.
2192 channel_input_port_forward_request(int is_root, int gateway_ports)
2194 u_short port, host_port;
2197 /* Get arguments from the packet. */
2198 port = packet_get_int();
2199 hostname = packet_get_string(NULL);
2200 host_port = packet_get_int();
2204 * Check that an unprivileged user is not trying to forward a
2207 if (port < IPPORT_RESERVED && !is_root)
2208 packet_disconnect("Requested forwarding of port %d but user is not root.",
2211 /* Initiate forwarding */
2212 channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports);
2214 /* Free the argument string. */
2219 * Permits opening to any host/port if permitted_opens[] is empty. This is
2220 * usually called by the server, because the user could connect to any port
2221 * anyway, and the server has no way to know but to trust the client anyway.
2224 channel_permit_all_opens(void)
2226 if (num_permitted_opens == 0)
2227 all_opens_permitted = 1;
2231 channel_add_permitted_opens(char *host, int port)
2233 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2234 fatal("channel_request_remote_forwarding: too many forwards");
2235 debug("allow port forwarding to host %s port %d", host, port);
2237 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2238 permitted_opens[num_permitted_opens].port_to_connect = port;
2239 num_permitted_opens++;
2241 all_opens_permitted = 0;
2245 channel_clear_permitted_opens(void)
2249 for (i = 0; i < num_permitted_opens; i++)
2250 xfree(permitted_opens[i].host_to_connect);
2251 num_permitted_opens = 0;
2256 /* return socket to remote host, port */
2258 connect_to(const char *host, u_short port)
2260 struct addrinfo hints, *ai, *aitop;
2261 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2265 memset(&hints, 0, sizeof(hints));
2266 hints.ai_family = IPv4or6;
2267 hints.ai_socktype = SOCK_STREAM;
2268 snprintf(strport, sizeof strport, "%d", port);
2269 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2270 error("connect_to %.100s: unknown host (%s)", host,
2271 gai_strerror(gaierr));
2274 for (ai = aitop; ai; ai = ai->ai_next) {
2275 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2277 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2278 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2279 error("connect_to: getnameinfo failed");
2282 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2284 error("socket: %.100s", strerror(errno));
2287 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2288 fatal("connect_to: F_SETFL: %s", strerror(errno));
2289 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2290 errno != EINPROGRESS) {
2291 error("connect_to %.100s port %s: %.100s", ntop, strport,
2294 continue; /* fail -- try next */
2296 break; /* success */
2299 freeaddrinfo(aitop);
2301 error("connect_to %.100s port %d: failed.", host, port);
2310 channel_connect_by_listen_address(u_short listen_port)
2314 for (i = 0; i < num_permitted_opens; i++)
2315 if (permitted_opens[i].listen_port == listen_port)
2317 permitted_opens[i].host_to_connect,
2318 permitted_opens[i].port_to_connect);
2319 error("WARNING: Server requests forwarding for unknown listen_port %d",
2324 /* Check if connecting to that port is permitted and connect. */
2326 channel_connect_to(const char *host, u_short port)
2330 permit = all_opens_permitted;
2332 for (i = 0; i < num_permitted_opens; i++)
2333 if (permitted_opens[i].port_to_connect == port &&
2334 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2339 log("Received request to connect to host %.100s port %d, "
2340 "but the request was denied.", host, port);
2343 return connect_to(host, port);
2346 /* -- X11 forwarding */
2349 * Creates an internet domain socket for listening for X11 connections.
2350 * Returns 0 and a suitable display number for the DISPLAY variable
2351 * stored in display_numberp , or -1 if an error occurs.
2354 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2355 int single_connection, u_int *display_numberp)
2358 int display_number, sock;
2360 struct addrinfo hints, *ai, *aitop;
2361 char strport[NI_MAXSERV];
2362 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2364 for (display_number = x11_display_offset;
2365 display_number < MAX_DISPLAYS;
2367 port = 6000 + display_number;
2368 memset(&hints, 0, sizeof(hints));
2369 hints.ai_family = IPv4or6;
2370 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2371 hints.ai_socktype = SOCK_STREAM;
2372 snprintf(strport, sizeof strport, "%d", port);
2373 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2374 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2377 for (ai = aitop; ai; ai = ai->ai_next) {
2378 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2380 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2382 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2383 error("socket: %.100s", strerror(errno));
2386 debug("x11_create_display_inet: Socket family %d not supported",
2392 if (ai->ai_family == AF_INET6) {
2394 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2395 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2398 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2399 debug("bind port %d: %.100s", port, strerror(errno));
2405 for (n = 0; n < num_socks; n++) {
2411 socks[num_socks++] = sock;
2412 #ifndef DONT_TRY_OTHER_AF
2413 if (num_socks == NUM_SOCKS)
2416 if (x11_use_localhost) {
2417 if (num_socks == NUM_SOCKS)
2424 freeaddrinfo(aitop);
2428 if (display_number >= MAX_DISPLAYS) {
2429 error("Failed to allocate internet-domain X11 display socket.");
2432 /* Start listening for connections on the socket. */
2433 for (n = 0; n < num_socks; n++) {
2435 if (listen(sock, 5) < 0) {
2436 error("listen: %.100s", strerror(errno));
2442 /* Allocate a channel for each socket. */
2443 for (n = 0; n < num_socks; n++) {
2445 nc = channel_new("x11 listener",
2446 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2447 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2448 0, xstrdup("X11 inet listener"), 1);
2449 nc->single_connection = single_connection;
2452 /* Return the display number for the DISPLAY environment variable. */
2453 *display_numberp = display_number;
2458 connect_local_xsocket(u_int dnr)
2461 struct sockaddr_un addr;
2463 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2465 error("socket: %.100s", strerror(errno));
2466 memset(&addr, 0, sizeof(addr));
2467 addr.sun_family = AF_UNIX;
2468 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2469 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2472 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2477 x11_connect_display(void)
2479 int display_number, sock = 0;
2480 const char *display;
2481 char buf[1024], *cp;
2482 struct addrinfo hints, *ai, *aitop;
2483 char strport[NI_MAXSERV];
2486 /* Try to open a socket for the local X server. */
2487 display = getenv("DISPLAY");
2489 error("DISPLAY not set.");
2493 * Now we decode the value of the DISPLAY variable and make a
2494 * connection to the real X server.
2498 * Check if it is a unix domain socket. Unix domain displays are in
2499 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2501 if (strncmp(display, "unix:", 5) == 0 ||
2502 display[0] == ':') {
2503 /* Connect to the unix domain socket. */
2504 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2505 error("Could not parse display number from DISPLAY: %.100s",
2509 /* Create a socket. */
2510 sock = connect_local_xsocket(display_number);
2514 /* OK, we now have a connection to the display. */
2518 * Connect to an inet socket. The DISPLAY value is supposedly
2519 * hostname:d[.s], where hostname may also be numeric IP address.
2521 strlcpy(buf, display, sizeof(buf));
2522 cp = strchr(buf, ':');
2524 error("Could not find ':' in DISPLAY: %.100s", display);
2528 /* buf now contains the host name. But first we parse the display number. */
2529 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2530 error("Could not parse display number from DISPLAY: %.100s",
2535 /* Look up the host address */
2536 memset(&hints, 0, sizeof(hints));
2537 hints.ai_family = IPv4or6;
2538 hints.ai_socktype = SOCK_STREAM;
2539 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2540 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2541 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2544 for (ai = aitop; ai; ai = ai->ai_next) {
2545 /* Create a socket. */
2546 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2548 debug("socket: %.100s", strerror(errno));
2551 /* Connect it to the display. */
2552 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2553 debug("connect %.100s port %d: %.100s", buf,
2554 6000 + display_number, strerror(errno));
2561 freeaddrinfo(aitop);
2563 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2572 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2573 * the remote channel number. We should do whatever we want, and respond
2574 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2578 x11_input_open(int type, u_int32_t seq, void *ctxt)
2581 int remote_id, sock = 0;
2584 debug("Received X11 open request.");
2586 remote_id = packet_get_int();
2588 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2589 remote_host = packet_get_string(NULL);
2591 remote_host = xstrdup("unknown (remote did not supply name)");
2595 /* Obtain a connection to the real X display. */
2596 sock = x11_connect_display();
2598 /* Allocate a channel for this connection. */
2599 c = channel_new("connected x11 socket",
2600 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2602 c->remote_id = remote_id;
2606 /* Send refusal to the remote host. */
2607 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2608 packet_put_int(remote_id);
2610 /* Send a confirmation to the remote host. */
2611 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2612 packet_put_int(remote_id);
2613 packet_put_int(c->self);
2618 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2620 deny_input_open(int type, u_int32_t seq, void *ctxt)
2622 int rchan = packet_get_int();
2625 case SSH_SMSG_AGENT_OPEN:
2626 error("Warning: ssh server tried agent forwarding.");
2628 case SSH_SMSG_X11_OPEN:
2629 error("Warning: ssh server tried X11 forwarding.");
2632 error("deny_input_open: type %d", type);
2635 error("Warning: this is probably a break in attempt by a malicious server.");
2636 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2637 packet_put_int(rchan);
2642 * Requests forwarding of X11 connections, generates fake authentication
2643 * data, and enables authentication spoofing.
2644 * This should be called in the client only.
2647 x11_request_forwarding_with_spoofing(int client_session_id,
2648 const char *proto, const char *data)
2650 u_int data_len = (u_int) strlen(data) / 2;
2651 u_int i, value, len;
2657 cp = getenv("DISPLAY");
2659 cp = strchr(cp, ':');
2661 cp = strchr(cp, '.');
2663 screen_number = atoi(cp + 1);
2667 /* Save protocol name. */
2668 x11_saved_proto = xstrdup(proto);
2671 * Extract real authentication data and generate fake data of the
2674 x11_saved_data = xmalloc(data_len);
2675 x11_fake_data = xmalloc(data_len);
2676 for (i = 0; i < data_len; i++) {
2677 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2678 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2680 rand = arc4random();
2681 x11_saved_data[i] = value;
2682 x11_fake_data[i] = rand & 0xff;
2685 x11_saved_data_len = data_len;
2686 x11_fake_data_len = data_len;
2688 /* Convert the fake data into hex. */
2689 len = 2 * data_len + 1;
2690 new_data = xmalloc(len);
2691 for (i = 0; i < data_len; i++)
2692 snprintf(new_data + 2 * i, len - 2 * i,
2693 "%02x", (u_char) x11_fake_data[i]);
2695 /* Send the request packet. */
2697 channel_request_start(client_session_id, "x11-req", 0);
2698 packet_put_char(0); /* XXX bool single connection */
2700 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2702 packet_put_cstring(proto);
2703 packet_put_cstring(new_data);
2704 packet_put_int(screen_number);
2706 packet_write_wait();
2711 /* -- agent forwarding */
2713 /* Sends a message to the server to request authentication fd forwarding. */
2716 auth_request_forwarding(void)
2718 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2720 packet_write_wait();
2723 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2726 auth_input_open_request(int type, u_int32_t seq, void *ctxt)
2729 int remote_id, sock;
2732 /* Read the remote channel number from the message. */
2733 remote_id = packet_get_int();
2737 * Get a connection to the local authentication agent (this may again
2740 sock = ssh_get_authentication_socket();
2743 * If we could not connect the agent, send an error message back to
2744 * the server. This should never happen unless the agent dies,
2745 * because authentication forwarding is only enabled if we have an
2749 name = xstrdup("authentication agent connection");
2750 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2751 -1, 0, 0, 0, name, 1);
2752 c->remote_id = remote_id;
2756 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2757 packet_put_int(remote_id);
2759 /* Send a confirmation to the remote host. */
2760 debug("Forwarding authentication connection.");
2761 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2762 packet_put_int(remote_id);
2763 packet_put_int(c->self);