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 1.175 2002/06/10 22:28:41 markus 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 int window, 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 debug2("channel: expanding %d", channels_alloc);
233 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
234 for (i = found; i < channels_alloc; i++)
237 /* Initialize and return new channel. */
238 c = channels[found] = xmalloc(sizeof(Channel));
239 memset(c, 0, sizeof(Channel));
240 buffer_init(&c->input);
241 buffer_init(&c->output);
242 buffer_init(&c->extended);
243 c->ostate = CHAN_OUTPUT_OPEN;
244 c->istate = CHAN_INPUT_OPEN;
246 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
250 c->local_window = window;
251 c->local_window_max = window;
252 c->local_consumed = 0;
253 c->local_maxpacket = maxpack;
255 c->remote_name = remote_name;
256 c->remote_window = 0;
257 c->remote_maxpacket = 0;
259 c->single_connection = 0;
260 c->detach_user = NULL;
262 c->input_filter = NULL;
263 debug("channel %d: new [%s]", found, remote_name);
268 channel_find_maxfd(void)
273 for (i = 0; i < channels_alloc; i++) {
276 max = MAX(max, c->rfd);
277 max = MAX(max, c->wfd);
278 max = MAX(max, c->efd);
285 channel_close_fd(int *fdp)
287 int ret = 0, fd = *fdp;
292 if (fd == channel_max_fd)
293 channel_max_fd = channel_find_maxfd();
298 /* Close all channel fd/socket. */
301 channel_close_fds(Channel *c)
303 debug3("channel_close_fds: channel %d: r %d w %d e %d",
304 c->self, c->rfd, c->wfd, c->efd);
306 channel_close_fd(&c->sock);
307 channel_close_fd(&c->rfd);
308 channel_close_fd(&c->wfd);
309 channel_close_fd(&c->efd);
312 /* Free the channel and close its fd/socket. */
315 channel_free(Channel *c)
320 for (n = 0, i = 0; i < channels_alloc; i++)
323 debug("channel_free: channel %d: %s, nchannels %d", c->self,
324 c->remote_name ? c->remote_name : "???", n);
326 s = channel_open_message();
327 debug3("channel_free: status: %s", s);
331 shutdown(c->sock, SHUT_RDWR);
332 channel_close_fds(c);
333 buffer_free(&c->input);
334 buffer_free(&c->output);
335 buffer_free(&c->extended);
336 if (c->remote_name) {
337 xfree(c->remote_name);
338 c->remote_name = NULL;
340 channels[c->self] = NULL;
345 channel_free_all(void)
349 for (i = 0; i < channels_alloc; i++)
350 if (channels[i] != NULL)
351 channel_free(channels[i]);
355 * Closes the sockets/fds of all channels. This is used to close extra file
356 * descriptors after a fork.
360 channel_close_all(void)
364 for (i = 0; i < channels_alloc; i++)
365 if (channels[i] != NULL)
366 channel_close_fds(channels[i]);
370 * Stop listening to channels.
374 channel_stop_listening(void)
379 for (i = 0; i < channels_alloc; i++) {
383 case SSH_CHANNEL_AUTH_SOCKET:
384 case SSH_CHANNEL_PORT_LISTENER:
385 case SSH_CHANNEL_RPORT_LISTENER:
386 case SSH_CHANNEL_X11_LISTENER:
387 channel_close_fd(&c->sock);
396 * Returns true if no channel has too much buffered data, and false if one or
397 * more channel is overfull.
401 channel_not_very_much_buffered_data(void)
406 for (i = 0; i < channels_alloc; i++) {
408 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
411 buffer_len(&c->input) > packet_get_maxsize()) {
412 debug("channel %d: big input buffer %d",
413 c->self, buffer_len(&c->input));
417 if (buffer_len(&c->output) > packet_get_maxsize()) {
418 debug("channel %d: big output buffer %d > %d",
419 c->self, buffer_len(&c->output),
420 packet_get_maxsize());
428 /* Returns true if any channel is still open. */
431 channel_still_open(void)
436 for (i = 0; i < channels_alloc; i++) {
441 case SSH_CHANNEL_X11_LISTENER:
442 case SSH_CHANNEL_PORT_LISTENER:
443 case SSH_CHANNEL_RPORT_LISTENER:
444 case SSH_CHANNEL_CLOSED:
445 case SSH_CHANNEL_AUTH_SOCKET:
446 case SSH_CHANNEL_DYNAMIC:
447 case SSH_CHANNEL_CONNECTING:
448 case SSH_CHANNEL_ZOMBIE:
450 case SSH_CHANNEL_LARVAL:
452 fatal("cannot happen: SSH_CHANNEL_LARVAL");
454 case SSH_CHANNEL_OPENING:
455 case SSH_CHANNEL_OPEN:
456 case SSH_CHANNEL_X11_OPEN:
458 case SSH_CHANNEL_INPUT_DRAINING:
459 case SSH_CHANNEL_OUTPUT_DRAINING:
461 fatal("cannot happen: OUT_DRAIN");
464 fatal("channel_still_open: bad channel type %d", c->type);
471 /* Returns the id of an open channel suitable for keepaliving */
474 channel_find_open(void)
479 for (i = 0; i < channels_alloc; i++) {
484 case SSH_CHANNEL_CLOSED:
485 case SSH_CHANNEL_DYNAMIC:
486 case SSH_CHANNEL_X11_LISTENER:
487 case SSH_CHANNEL_PORT_LISTENER:
488 case SSH_CHANNEL_RPORT_LISTENER:
489 case SSH_CHANNEL_OPENING:
490 case SSH_CHANNEL_CONNECTING:
491 case SSH_CHANNEL_ZOMBIE:
493 case SSH_CHANNEL_LARVAL:
494 case SSH_CHANNEL_AUTH_SOCKET:
495 case SSH_CHANNEL_OPEN:
496 case SSH_CHANNEL_X11_OPEN:
498 case SSH_CHANNEL_INPUT_DRAINING:
499 case SSH_CHANNEL_OUTPUT_DRAINING:
501 fatal("cannot happen: OUT_DRAIN");
504 fatal("channel_find_open: bad channel type %d", c->type);
513 * Returns a message describing the currently open forwarded connections,
514 * suitable for sending to the client. The message contains crlf pairs for
519 channel_open_message(void)
526 buffer_init(&buffer);
527 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
528 buffer_append(&buffer, buf, strlen(buf));
529 for (i = 0; i < channels_alloc; i++) {
534 case SSH_CHANNEL_X11_LISTENER:
535 case SSH_CHANNEL_PORT_LISTENER:
536 case SSH_CHANNEL_RPORT_LISTENER:
537 case SSH_CHANNEL_CLOSED:
538 case SSH_CHANNEL_AUTH_SOCKET:
539 case SSH_CHANNEL_ZOMBIE:
541 case SSH_CHANNEL_LARVAL:
542 case SSH_CHANNEL_OPENING:
543 case SSH_CHANNEL_CONNECTING:
544 case SSH_CHANNEL_DYNAMIC:
545 case SSH_CHANNEL_OPEN:
546 case SSH_CHANNEL_X11_OPEN:
547 case SSH_CHANNEL_INPUT_DRAINING:
548 case SSH_CHANNEL_OUTPUT_DRAINING:
549 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
550 c->self, c->remote_name,
551 c->type, c->remote_id,
552 c->istate, buffer_len(&c->input),
553 c->ostate, buffer_len(&c->output),
555 buffer_append(&buffer, buf, strlen(buf));
558 fatal("channel_open_message: bad channel type %d", c->type);
562 buffer_append(&buffer, "\0", 1);
563 cp = xstrdup(buffer_ptr(&buffer));
564 buffer_free(&buffer);
569 channel_send_open(int id)
571 Channel *c = channel_lookup(id);
573 log("channel_send_open: %d: bad id", id);
576 debug("send channel open %d", id);
577 packet_start(SSH2_MSG_CHANNEL_OPEN);
578 packet_put_cstring(c->ctype);
579 packet_put_int(c->self);
580 packet_put_int(c->local_window);
581 packet_put_int(c->local_maxpacket);
586 channel_request_start(int local_id, char *service, int wantconfirm)
588 Channel *c = channel_lookup(local_id);
590 log("channel_request_start: %d: unknown channel id", local_id);
593 debug("channel request %d: %s", local_id, service) ;
594 packet_start(SSH2_MSG_CHANNEL_REQUEST);
595 packet_put_int(c->remote_id);
596 packet_put_cstring(service);
597 packet_put_char(wantconfirm);
600 channel_register_confirm(int id, channel_callback_fn *fn)
602 Channel *c = channel_lookup(id);
604 log("channel_register_comfirm: %d: bad id", id);
610 channel_register_cleanup(int id, channel_callback_fn *fn)
612 Channel *c = channel_lookup(id);
614 log("channel_register_cleanup: %d: bad id", id);
620 channel_cancel_cleanup(int id)
622 Channel *c = channel_lookup(id);
624 log("channel_cancel_cleanup: %d: bad id", id);
627 c->detach_user = NULL;
630 channel_register_filter(int id, channel_filter_fn *fn)
632 Channel *c = channel_lookup(id);
634 log("channel_register_filter: %d: bad id", id);
637 c->input_filter = fn;
641 channel_set_fds(int id, int rfd, int wfd, int efd,
642 int extusage, int nonblock, u_int window_max)
644 Channel *c = channel_lookup(id);
645 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
646 fatal("channel_activate for non-larval channel %d.", id);
647 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
648 c->type = SSH_CHANNEL_OPEN;
649 c->local_window = c->local_window_max = window_max;
650 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
651 packet_put_int(c->remote_id);
652 packet_put_int(c->local_window);
657 * 'channel_pre*' are called just before select() to add any bits relevant to
658 * channels in the select bitmasks.
661 * 'channel_post*': perform any appropriate operations for channels which
662 * have events pending.
664 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
665 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
666 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
669 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
671 FD_SET(c->sock, readset);
675 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
677 debug3("channel %d: waiting for connection", c->self);
678 FD_SET(c->sock, writeset);
682 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
684 if (buffer_len(&c->input) < packet_get_maxsize())
685 FD_SET(c->sock, readset);
686 if (buffer_len(&c->output) > 0)
687 FD_SET(c->sock, writeset);
691 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
693 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
695 if (c->istate == CHAN_INPUT_OPEN &&
697 buffer_len(&c->input) < limit)
698 FD_SET(c->rfd, readset);
699 if (c->ostate == CHAN_OUTPUT_OPEN ||
700 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
701 if (buffer_len(&c->output) > 0) {
702 FD_SET(c->wfd, writeset);
703 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
704 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
705 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
706 c->self, c->efd, buffer_len(&c->extended));
711 /** XXX check close conditions, too */
712 if (compat20 && c->efd != -1) {
713 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
714 buffer_len(&c->extended) > 0)
715 FD_SET(c->efd, writeset);
716 else if (!(c->flags & CHAN_EOF_SENT) &&
717 c->extended_usage == CHAN_EXTENDED_READ &&
718 buffer_len(&c->extended) < c->remote_window)
719 FD_SET(c->efd, readset);
724 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
726 if (buffer_len(&c->input) == 0) {
727 packet_start(SSH_MSG_CHANNEL_CLOSE);
728 packet_put_int(c->remote_id);
730 c->type = SSH_CHANNEL_CLOSED;
731 debug("channel %d: closing after input drain.", c->self);
736 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
738 if (buffer_len(&c->output) == 0)
741 FD_SET(c->sock, writeset);
745 * This is a special state for X11 authentication spoofing. An opened X11
746 * connection (when authentication spoofing is being done) remains in this
747 * state until the first packet has been completely read. The authentication
748 * data in that packet is then substituted by the real data if it matches the
749 * fake data, and the channel is put into normal mode.
750 * XXX All this happens at the client side.
751 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
754 x11_open_helper(Buffer *b)
757 u_int proto_len, data_len;
759 /* Check if the fixed size part of the packet is in buffer. */
760 if (buffer_len(b) < 12)
763 /* Parse the lengths of variable-length fields. */
765 if (ucp[0] == 0x42) { /* Byte order MSB first. */
766 proto_len = 256 * ucp[6] + ucp[7];
767 data_len = 256 * ucp[8] + ucp[9];
768 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
769 proto_len = ucp[6] + 256 * ucp[7];
770 data_len = ucp[8] + 256 * ucp[9];
772 debug("Initial X11 packet contains bad byte order byte: 0x%x",
777 /* Check if the whole packet is in buffer. */
779 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
782 /* Check if authentication protocol matches. */
783 if (proto_len != strlen(x11_saved_proto) ||
784 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
785 debug("X11 connection uses different authentication protocol.");
788 /* Check if authentication data matches our fake data. */
789 if (data_len != x11_fake_data_len ||
790 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
791 x11_fake_data, x11_fake_data_len) != 0) {
792 debug("X11 auth data does not match fake data.");
795 /* Check fake data length */
796 if (x11_fake_data_len != x11_saved_data_len) {
797 error("X11 fake_data_len %d != saved_data_len %d",
798 x11_fake_data_len, x11_saved_data_len);
802 * Received authentication protocol and data match
803 * our fake data. Substitute the fake data with real
806 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
807 x11_saved_data, x11_saved_data_len);
812 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
814 int ret = x11_open_helper(&c->output);
816 /* Start normal processing for the channel. */
817 c->type = SSH_CHANNEL_OPEN;
818 channel_pre_open_13(c, readset, writeset);
819 } else if (ret == -1) {
821 * We have received an X11 connection that has bad
822 * authentication information.
824 log("X11 connection rejected because of wrong authentication.");
825 buffer_clear(&c->input);
826 buffer_clear(&c->output);
827 channel_close_fd(&c->sock);
829 c->type = SSH_CHANNEL_CLOSED;
830 packet_start(SSH_MSG_CHANNEL_CLOSE);
831 packet_put_int(c->remote_id);
837 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
839 int ret = x11_open_helper(&c->output);
841 /* c->force_drain = 1; */
844 c->type = SSH_CHANNEL_OPEN;
845 channel_pre_open(c, readset, writeset);
846 } else if (ret == -1) {
847 log("X11 connection rejected because of wrong authentication.");
848 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
850 buffer_clear(&c->input);
852 buffer_clear(&c->output);
853 /* for proto v1, the peer will send an IEOF */
855 chan_write_failed(c);
857 c->type = SSH_CHANNEL_OPEN;
858 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
862 /* try to decode a socks4 header */
864 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
867 int len, have, i, found;
873 struct in_addr dest_addr;
876 debug2("channel %d: decode socks4", c->self);
878 have = buffer_len(&c->input);
879 len = sizeof(s4_req);
882 p = buffer_ptr(&c->input);
883 for (found = 0, i = len; i < have; i++) {
889 /* the peer is probably sending garbage */
890 debug("channel %d: decode socks4: too long",
897 buffer_get(&c->input, (char *)&s4_req.version, 1);
898 buffer_get(&c->input, (char *)&s4_req.command, 1);
899 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
900 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
901 have = buffer_len(&c->input);
902 p = buffer_ptr(&c->input);
904 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
906 fatal("channel %d: decode socks4: len %d > have %d",
908 strlcpy(username, p, sizeof(username));
909 buffer_consume(&c->input, len);
910 buffer_consume(&c->input, 1); /* trailing '\0' */
912 host = inet_ntoa(s4_req.dest_addr);
913 strlcpy(c->path, host, sizeof(c->path));
914 c->host_port = ntohs(s4_req.dest_port);
916 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
917 c->self, host, c->host_port, s4_req.command);
919 if (s4_req.command != 1) {
920 debug("channel %d: cannot handle: socks4 cn %d",
921 c->self, s4_req.command);
924 s4_rsp.version = 0; /* vn: 0 for reply */
925 s4_rsp.command = 90; /* cd: req granted */
926 s4_rsp.dest_port = 0; /* ignored */
927 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
928 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
932 /* dynamic port forwarding */
934 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
939 have = buffer_len(&c->input);
941 debug2("channel %d: pre_dynamic: have %d", c->self, have);
942 /* buffer_dump(&c->input); */
943 /* check if the fixed size part of the packet is in buffer. */
946 FD_SET(c->sock, readset);
949 /* try to guess the protocol */
950 p = buffer_ptr(&c->input);
953 ret = channel_decode_socks4(c, readset, writeset);
961 } else if (ret == 0) {
962 debug2("channel %d: pre_dynamic: need more", c->self);
964 FD_SET(c->sock, readset);
966 /* switch to the next state */
967 c->type = SSH_CHANNEL_OPENING;
968 port_open_helper(c, "direct-tcpip");
972 /* This is our fake X11 server socket. */
974 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
977 struct sockaddr addr;
980 char buf[16384], *remote_ipaddr;
983 if (FD_ISSET(c->sock, readset)) {
984 debug("X11 connection requested.");
985 addrlen = sizeof(addr);
986 newsock = accept(c->sock, &addr, &addrlen);
987 if (c->single_connection) {
988 debug("single_connection: closing X11 listener.");
989 channel_close_fd(&c->sock);
993 error("accept: %.100s", strerror(errno));
996 set_nodelay(newsock);
997 remote_ipaddr = get_peer_ipaddr(newsock);
998 remote_port = get_peer_port(newsock);
999 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1000 remote_ipaddr, remote_port);
1002 nc = channel_new("accepted x11 socket",
1003 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1004 c->local_window_max, c->local_maxpacket,
1005 0, xstrdup(buf), 1);
1007 packet_start(SSH2_MSG_CHANNEL_OPEN);
1008 packet_put_cstring("x11");
1009 packet_put_int(nc->self);
1010 packet_put_int(nc->local_window_max);
1011 packet_put_int(nc->local_maxpacket);
1012 /* originator ipaddr and port */
1013 packet_put_cstring(remote_ipaddr);
1014 if (datafellows & SSH_BUG_X11FWD) {
1015 debug("ssh2 x11 bug compat mode");
1017 packet_put_int(remote_port);
1021 packet_start(SSH_SMSG_X11_OPEN);
1022 packet_put_int(nc->self);
1023 if (packet_get_protocol_flags() &
1024 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1025 packet_put_cstring(buf);
1028 xfree(remote_ipaddr);
1033 port_open_helper(Channel *c, char *rtype)
1037 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1038 u_short remote_port = get_peer_port(c->sock);
1040 direct = (strcmp(rtype, "direct-tcpip") == 0);
1042 snprintf(buf, sizeof buf,
1043 "%s: listening port %d for %.100s port %d, "
1044 "connect from %.200s port %d",
1045 rtype, c->listening_port, c->path, c->host_port,
1046 remote_ipaddr, remote_port);
1048 xfree(c->remote_name);
1049 c->remote_name = xstrdup(buf);
1052 packet_start(SSH2_MSG_CHANNEL_OPEN);
1053 packet_put_cstring(rtype);
1054 packet_put_int(c->self);
1055 packet_put_int(c->local_window_max);
1056 packet_put_int(c->local_maxpacket);
1058 /* target host, port */
1059 packet_put_cstring(c->path);
1060 packet_put_int(c->host_port);
1062 /* listen address, port */
1063 packet_put_cstring(c->path);
1064 packet_put_int(c->listening_port);
1066 /* originator host and port */
1067 packet_put_cstring(remote_ipaddr);
1068 packet_put_int(remote_port);
1071 packet_start(SSH_MSG_PORT_OPEN);
1072 packet_put_int(c->self);
1073 packet_put_cstring(c->path);
1074 packet_put_int(c->host_port);
1075 if (packet_get_protocol_flags() &
1076 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1077 packet_put_cstring(c->remote_name);
1080 xfree(remote_ipaddr);
1084 * This socket is listening for connections to a forwarded TCP/IP port.
1087 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1090 struct sockaddr addr;
1091 int newsock, nextstate;
1095 if (FD_ISSET(c->sock, readset)) {
1096 debug("Connection to port %d forwarding "
1097 "to %.100s port %d requested.",
1098 c->listening_port, c->path, c->host_port);
1100 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1101 nextstate = SSH_CHANNEL_OPENING;
1102 rtype = "forwarded-tcpip";
1104 if (c->host_port == 0) {
1105 nextstate = SSH_CHANNEL_DYNAMIC;
1106 rtype = "dynamic-tcpip";
1108 nextstate = SSH_CHANNEL_OPENING;
1109 rtype = "direct-tcpip";
1113 addrlen = sizeof(addr);
1114 newsock = accept(c->sock, &addr, &addrlen);
1116 error("accept: %.100s", strerror(errno));
1119 set_nodelay(newsock);
1120 nc = channel_new(rtype,
1121 nextstate, newsock, newsock, -1,
1122 c->local_window_max, c->local_maxpacket,
1123 0, xstrdup(rtype), 1);
1124 nc->listening_port = c->listening_port;
1125 nc->host_port = c->host_port;
1126 strlcpy(nc->path, c->path, sizeof(nc->path));
1128 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1130 * do not call the channel_post handler until
1131 * this flag has been reset by a pre-handler.
1132 * otherwise the FD_ISSET calls might overflow
1136 port_open_helper(nc, rtype);
1142 * This is the authentication agent socket listening for connections from
1146 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1151 struct sockaddr addr;
1154 if (FD_ISSET(c->sock, readset)) {
1155 addrlen = sizeof(addr);
1156 newsock = accept(c->sock, &addr, &addrlen);
1158 error("accept from auth socket: %.100s", strerror(errno));
1161 name = xstrdup("accepted auth socket");
1162 nc = channel_new("accepted auth socket",
1163 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1164 c->local_window_max, c->local_maxpacket,
1167 packet_start(SSH2_MSG_CHANNEL_OPEN);
1168 packet_put_cstring("auth-agent@openssh.com");
1169 packet_put_int(nc->self);
1170 packet_put_int(c->local_window_max);
1171 packet_put_int(c->local_maxpacket);
1173 packet_start(SSH_SMSG_AGENT_OPEN);
1174 packet_put_int(nc->self);
1181 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1184 socklen_t sz = sizeof(err);
1186 if (FD_ISSET(c->sock, writeset)) {
1187 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1189 error("getsockopt SO_ERROR failed");
1192 debug("channel %d: connected", c->self);
1193 c->type = SSH_CHANNEL_OPEN;
1195 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1196 packet_put_int(c->remote_id);
1197 packet_put_int(c->self);
1198 packet_put_int(c->local_window);
1199 packet_put_int(c->local_maxpacket);
1201 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1202 packet_put_int(c->remote_id);
1203 packet_put_int(c->self);
1206 debug("channel %d: not connected: %s",
1207 c->self, strerror(err));
1209 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1210 packet_put_int(c->remote_id);
1211 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1212 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1213 packet_put_cstring(strerror(err));
1214 packet_put_cstring("");
1217 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1218 packet_put_int(c->remote_id);
1227 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1233 FD_ISSET(c->rfd, readset)) {
1234 len = read(c->rfd, buf, sizeof(buf));
1235 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1238 debug("channel %d: read<=0 rfd %d len %d",
1239 c->self, c->rfd, len);
1240 if (c->type != SSH_CHANNEL_OPEN) {
1241 debug("channel %d: not open", c->self);
1244 } else if (compat13) {
1245 buffer_clear(&c->output);
1246 c->type = SSH_CHANNEL_INPUT_DRAINING;
1247 debug("channel %d: input draining.", c->self);
1249 chan_read_failed(c);
1253 if (c->input_filter != NULL) {
1254 if (c->input_filter(c, buf, len) == -1) {
1255 debug("channel %d: filter stops", c->self);
1256 chan_read_failed(c);
1259 buffer_append(&c->input, buf, len);
1265 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1272 /* Send buffered output data to the socket. */
1274 FD_ISSET(c->wfd, writeset) &&
1275 buffer_len(&c->output) > 0) {
1276 data = buffer_ptr(&c->output);
1277 dlen = buffer_len(&c->output);
1278 len = write(c->wfd, data, dlen);
1279 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1282 if (c->type != SSH_CHANNEL_OPEN) {
1283 debug("channel %d: not open", c->self);
1286 } else if (compat13) {
1287 buffer_clear(&c->output);
1288 debug("channel %d: input draining.", c->self);
1289 c->type = SSH_CHANNEL_INPUT_DRAINING;
1291 chan_write_failed(c);
1295 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1296 if (tcgetattr(c->wfd, &tio) == 0 &&
1297 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1299 * Simulate echo to reduce the impact of
1300 * traffic analysis. We need to match the
1301 * size of a SSH2_MSG_CHANNEL_DATA message
1302 * (4 byte channel id + data)
1304 packet_send_ignore(4 + len);
1308 buffer_consume(&c->output, len);
1309 if (compat20 && len > 0) {
1310 c->local_consumed += len;
1316 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1321 /** XXX handle drain efd, too */
1323 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1324 FD_ISSET(c->efd, writeset) &&
1325 buffer_len(&c->extended) > 0) {
1326 len = write(c->efd, buffer_ptr(&c->extended),
1327 buffer_len(&c->extended));
1328 debug2("channel %d: written %d to efd %d",
1329 c->self, len, c->efd);
1330 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1333 debug2("channel %d: closing write-efd %d",
1335 channel_close_fd(&c->efd);
1337 buffer_consume(&c->extended, len);
1338 c->local_consumed += len;
1340 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1341 FD_ISSET(c->efd, readset)) {
1342 len = read(c->efd, buf, sizeof(buf));
1343 debug2("channel %d: read %d from efd %d",
1344 c->self, len, c->efd);
1345 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1348 debug2("channel %d: closing read-efd %d",
1350 channel_close_fd(&c->efd);
1352 buffer_append(&c->extended, buf, len);
1359 channel_check_window(Channel *c)
1361 if (c->type == SSH_CHANNEL_OPEN &&
1362 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1363 c->local_window < c->local_window_max/2 &&
1364 c->local_consumed > 0) {
1365 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1366 packet_put_int(c->remote_id);
1367 packet_put_int(c->local_consumed);
1369 debug2("channel %d: window %d sent adjust %d",
1370 c->self, c->local_window,
1372 c->local_window += c->local_consumed;
1373 c->local_consumed = 0;
1379 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1383 channel_handle_rfd(c, readset, writeset);
1384 channel_handle_wfd(c, readset, writeset);
1387 channel_handle_efd(c, readset, writeset);
1388 channel_check_window(c);
1392 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1395 /* Send buffered output data to the socket. */
1396 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1397 len = write(c->sock, buffer_ptr(&c->output),
1398 buffer_len(&c->output));
1400 buffer_clear(&c->output);
1402 buffer_consume(&c->output, len);
1407 channel_handler_init_20(void)
1409 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1410 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1411 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1412 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1413 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1414 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1415 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1416 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1418 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1419 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1420 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1421 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1422 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1423 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1424 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1428 channel_handler_init_13(void)
1430 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1431 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1432 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1433 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1434 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1435 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1436 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1437 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1438 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1440 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1441 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1442 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1443 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1444 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1445 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1446 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1450 channel_handler_init_15(void)
1452 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1453 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1454 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1455 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1456 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1457 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1458 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1460 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1461 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1462 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1463 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1464 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1465 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1469 channel_handler_init(void)
1472 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1473 channel_pre[i] = NULL;
1474 channel_post[i] = NULL;
1477 channel_handler_init_20();
1479 channel_handler_init_13();
1481 channel_handler_init_15();
1484 /* gc dead channels */
1486 channel_garbage_collect(Channel *c)
1490 if (c->detach_user != NULL) {
1491 if (!chan_is_dead(c, 0))
1493 debug("channel %d: gc: notify user", c->self);
1494 c->detach_user(c->self, NULL);
1495 /* if we still have a callback */
1496 if (c->detach_user != NULL)
1498 debug("channel %d: gc: user detached", c->self);
1500 if (!chan_is_dead(c, 1))
1502 debug("channel %d: garbage collecting", c->self);
1507 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1509 static int did_init = 0;
1514 channel_handler_init();
1517 for (i = 0; i < channels_alloc; i++) {
1521 if (ftab[c->type] != NULL)
1522 (*ftab[c->type])(c, readset, writeset);
1523 channel_garbage_collect(c);
1528 * Allocate/update select bitmasks and add any bits relevant to channels in
1532 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1533 int *nallocp, int rekeying)
1538 n = MAX(*maxfdp, channel_max_fd);
1540 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1541 /* perhaps check sz < nalloc/2 and shrink? */
1542 if (*readsetp == NULL || sz > *nallocp) {
1543 *readsetp = xrealloc(*readsetp, sz);
1544 *writesetp = xrealloc(*writesetp, sz);
1548 memset(*readsetp, 0, sz);
1549 memset(*writesetp, 0, sz);
1552 channel_handler(channel_pre, *readsetp, *writesetp);
1556 * After select, perform any appropriate operations for channels which have
1560 channel_after_select(fd_set * readset, fd_set * writeset)
1562 channel_handler(channel_post, readset, writeset);
1566 /* If there is data to send to the connection, enqueue some of it now. */
1569 channel_output_poll(void)
1574 for (i = 0; i < channels_alloc; i++) {
1580 * We are only interested in channels that can have buffered
1584 if (c->type != SSH_CHANNEL_OPEN &&
1585 c->type != SSH_CHANNEL_INPUT_DRAINING)
1588 if (c->type != SSH_CHANNEL_OPEN)
1592 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1593 /* XXX is this true? */
1594 debug3("channel %d: will not send data after close", c->self);
1598 /* Get the amount of buffered data for this channel. */
1599 if ((c->istate == CHAN_INPUT_OPEN ||
1600 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1601 (len = buffer_len(&c->input)) > 0) {
1603 * Send some data for the other side over the secure
1607 if (len > c->remote_window)
1608 len = c->remote_window;
1609 if (len > c->remote_maxpacket)
1610 len = c->remote_maxpacket;
1612 if (packet_is_interactive()) {
1616 /* Keep the packets at reasonable size. */
1617 if (len > packet_get_maxsize()/2)
1618 len = packet_get_maxsize()/2;
1622 packet_start(compat20 ?
1623 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1624 packet_put_int(c->remote_id);
1625 packet_put_string(buffer_ptr(&c->input), len);
1627 buffer_consume(&c->input, len);
1628 c->remote_window -= len;
1630 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1632 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1634 * input-buffer is empty and read-socket shutdown:
1635 * tell peer, that we will not send more data: send IEOF.
1636 * hack for extended data: delay EOF if EFD still in use.
1638 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1639 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1640 c->self, c->efd, buffer_len(&c->extended));
1644 /* Send extended data, i.e. stderr */
1646 !(c->flags & CHAN_EOF_SENT) &&
1647 c->remote_window > 0 &&
1648 (len = buffer_len(&c->extended)) > 0 &&
1649 c->extended_usage == CHAN_EXTENDED_READ) {
1650 debug2("channel %d: rwin %d elen %d euse %d",
1651 c->self, c->remote_window, buffer_len(&c->extended),
1653 if (len > c->remote_window)
1654 len = c->remote_window;
1655 if (len > c->remote_maxpacket)
1656 len = c->remote_maxpacket;
1657 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1658 packet_put_int(c->remote_id);
1659 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1660 packet_put_string(buffer_ptr(&c->extended), len);
1662 buffer_consume(&c->extended, len);
1663 c->remote_window -= len;
1664 debug2("channel %d: sent ext data %d", c->self, len);
1670 /* -- protocol input */
1673 channel_input_data(int type, u_int32_t seq, void *ctxt)
1680 /* Get the channel number and verify it. */
1681 id = packet_get_int();
1682 c = channel_lookup(id);
1684 packet_disconnect("Received data for nonexistent channel %d.", id);
1686 /* Ignore any data for non-open channels (might happen on close) */
1687 if (c->type != SSH_CHANNEL_OPEN &&
1688 c->type != SSH_CHANNEL_X11_OPEN)
1691 /* same for protocol 1.5 if output end is no longer open */
1692 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1696 data = packet_get_string(&data_len);
1699 if (data_len > c->local_maxpacket) {
1700 log("channel %d: rcvd big packet %d, maxpack %d",
1701 c->self, data_len, c->local_maxpacket);
1703 if (data_len > c->local_window) {
1704 log("channel %d: rcvd too much data %d, win %d",
1705 c->self, data_len, c->local_window);
1709 c->local_window -= data_len;
1712 buffer_append(&c->output, data, data_len);
1717 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1725 /* Get the channel number and verify it. */
1726 id = packet_get_int();
1727 c = channel_lookup(id);
1730 packet_disconnect("Received extended_data for bad channel %d.", id);
1731 if (c->type != SSH_CHANNEL_OPEN) {
1732 log("channel %d: ext data for non open", id);
1735 if (c->flags & CHAN_EOF_RCVD) {
1736 if (datafellows & SSH_BUG_EXTEOF)
1737 debug("channel %d: accepting ext data after eof", id);
1739 packet_disconnect("Received extended_data after EOF "
1740 "on channel %d.", id);
1742 tcode = packet_get_int();
1744 c->extended_usage != CHAN_EXTENDED_WRITE ||
1745 tcode != SSH2_EXTENDED_DATA_STDERR) {
1746 log("channel %d: bad ext data", c->self);
1749 data = packet_get_string(&data_len);
1751 if (data_len > c->local_window) {
1752 log("channel %d: rcvd too much extended_data %d, win %d",
1753 c->self, data_len, c->local_window);
1757 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1758 c->local_window -= data_len;
1759 buffer_append(&c->extended, data, data_len);
1764 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1769 id = packet_get_int();
1771 c = channel_lookup(id);
1773 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1776 /* XXX force input close */
1777 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1778 debug("channel %d: FORCE input drain", c->self);
1779 c->istate = CHAN_INPUT_WAIT_DRAIN;
1780 if (buffer_len(&c->input) == 0)
1787 channel_input_close(int type, u_int32_t seq, void *ctxt)
1792 id = packet_get_int();
1794 c = channel_lookup(id);
1796 packet_disconnect("Received close for nonexistent channel %d.", id);
1799 * Send a confirmation that we have closed the channel and no more
1800 * data is coming for it.
1802 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1803 packet_put_int(c->remote_id);
1807 * If the channel is in closed state, we have sent a close request,
1808 * and the other side will eventually respond with a confirmation.
1809 * Thus, we cannot free the channel here, because then there would be
1810 * no-one to receive the confirmation. The channel gets freed when
1811 * the confirmation arrives.
1813 if (c->type != SSH_CHANNEL_CLOSED) {
1815 * Not a closed channel - mark it as draining, which will
1816 * cause it to be freed later.
1818 buffer_clear(&c->input);
1819 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1823 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1825 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
1827 int id = packet_get_int();
1828 Channel *c = channel_lookup(id);
1832 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1833 chan_rcvd_oclose(c);
1837 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
1839 int id = packet_get_int();
1840 Channel *c = channel_lookup(id);
1844 packet_disconnect("Received close confirmation for "
1845 "out-of-range channel %d.", id);
1846 if (c->type != SSH_CHANNEL_CLOSED)
1847 packet_disconnect("Received close confirmation for "
1848 "non-closed channel %d (type %d).", id, c->type);
1853 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
1858 id = packet_get_int();
1859 c = channel_lookup(id);
1861 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1862 packet_disconnect("Received open confirmation for "
1863 "non-opening channel %d.", id);
1864 remote_id = packet_get_int();
1865 /* Record the remote channel number and mark that the channel is now open. */
1866 c->remote_id = remote_id;
1867 c->type = SSH_CHANNEL_OPEN;
1870 c->remote_window = packet_get_int();
1871 c->remote_maxpacket = packet_get_int();
1873 debug2("callback start");
1874 c->confirm(c->self, NULL);
1875 debug2("callback done");
1877 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1878 c->remote_window, c->remote_maxpacket);
1884 reason2txt(int reason)
1887 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1888 return "administratively prohibited";
1889 case SSH2_OPEN_CONNECT_FAILED:
1890 return "connect failed";
1891 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1892 return "unknown channel type";
1893 case SSH2_OPEN_RESOURCE_SHORTAGE:
1894 return "resource shortage";
1896 return "unknown reason";
1900 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
1903 char *msg = NULL, *lang = NULL;
1906 id = packet_get_int();
1907 c = channel_lookup(id);
1909 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1910 packet_disconnect("Received open failure for "
1911 "non-opening channel %d.", id);
1913 reason = packet_get_int();
1914 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1915 msg = packet_get_string(NULL);
1916 lang = packet_get_string(NULL);
1918 log("channel %d: open failed: %s%s%s", id,
1919 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1926 /* Free the channel. This will also close the socket. */
1931 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
1939 /* Get the channel number and verify it. */
1940 id = packet_get_int();
1941 c = channel_lookup(id);
1943 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1944 log("Received window adjust for "
1945 "non-open channel %d.", id);
1948 adjust = packet_get_int();
1950 debug2("channel %d: rcvd adjust %d", id, adjust);
1951 c->remote_window += adjust;
1955 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
1959 char *host, *originator_string;
1960 int remote_id, sock = -1;
1962 remote_id = packet_get_int();
1963 host = packet_get_string(NULL);
1964 host_port = packet_get_int();
1966 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
1967 originator_string = packet_get_string(NULL);
1969 originator_string = xstrdup("unknown (remote did not supply name)");
1972 sock = channel_connect_to(host, host_port);
1974 c = channel_new("connected socket",
1975 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
1976 originator_string, 1);
1977 c->remote_id = remote_id;
1980 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1981 packet_put_int(remote_id);
1988 /* -- tcp forwarding */
1991 channel_set_af(int af)
1997 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
1998 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2001 int success, sock, on = 1;
2002 struct addrinfo hints, *ai, *aitop;
2004 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2005 struct linger linger;
2008 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2009 listen_addr : host_to_connect;
2012 error("No forward host name.");
2015 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2016 error("Forward host name too long.");
2021 * getaddrinfo returns a loopback address if the hostname is
2022 * set to NULL and hints.ai_flags is not AI_PASSIVE
2024 memset(&hints, 0, sizeof(hints));
2025 hints.ai_family = IPv4or6;
2026 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2027 hints.ai_socktype = SOCK_STREAM;
2028 snprintf(strport, sizeof strport, "%d", listen_port);
2029 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2030 packet_disconnect("getaddrinfo: fatal error");
2032 for (ai = aitop; ai; ai = ai->ai_next) {
2033 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2035 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2036 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2037 error("channel_setup_fwd_listener: getnameinfo failed");
2040 /* Create a port to listen for the host. */
2041 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2043 /* this is no error since kernel may not support ipv6 */
2044 verbose("socket: %.100s", strerror(errno));
2048 * Set socket options. We would like the socket to disappear
2049 * as soon as it has been closed for whatever reason.
2051 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
2053 linger.l_linger = 5;
2054 setsockopt(sock, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
2055 debug("Local forwarding listening on %s port %s.", ntop, strport);
2057 /* Bind the socket to the address. */
2058 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2059 /* address can be in use ipv6 address is already bound */
2061 error("bind: %.100s", strerror(errno));
2063 verbose("bind: %.100s", strerror(errno));
2068 /* Start listening for connections on the socket. */
2069 if (listen(sock, 5) < 0) {
2070 error("listen: %.100s", strerror(errno));
2074 /* Allocate a channel number for the socket. */
2075 c = channel_new("port listener", type, sock, sock, -1,
2076 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2077 0, xstrdup("port listener"), 1);
2078 strlcpy(c->path, host, sizeof(c->path));
2079 c->host_port = port_to_connect;
2080 c->listening_port = listen_port;
2084 error("channel_setup_fwd_listener: cannot listen to port: %d",
2086 freeaddrinfo(aitop);
2090 /* protocol local port fwd, used by ssh (and sshd in v1) */
2092 channel_setup_local_fwd_listener(u_short listen_port,
2093 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2095 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2096 NULL, listen_port, host_to_connect, port_to_connect, gateway_ports);
2099 /* protocol v2 remote port fwd, used by sshd */
2101 channel_setup_remote_fwd_listener(const char *listen_address,
2102 u_short listen_port, int gateway_ports)
2104 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2105 listen_address, listen_port, NULL, 0, gateway_ports);
2109 * Initiate forwarding of connections to port "port" on remote host through
2110 * the secure channel to host:port from local side.
2114 channel_request_remote_forwarding(u_short listen_port,
2115 const char *host_to_connect, u_short port_to_connect)
2117 int type, success = 0;
2119 /* Record locally that connection to this host/port is permitted. */
2120 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2121 fatal("channel_request_remote_forwarding: too many forwards");
2123 /* Send the forward request to the remote side. */
2125 const char *address_to_bind = "0.0.0.0";
2126 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2127 packet_put_cstring("tcpip-forward");
2128 packet_put_char(1); /* boolean: want reply */
2129 packet_put_cstring(address_to_bind);
2130 packet_put_int(listen_port);
2132 packet_write_wait();
2133 /* Assume that server accepts the request */
2136 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2137 packet_put_int(listen_port);
2138 packet_put_cstring(host_to_connect);
2139 packet_put_int(port_to_connect);
2141 packet_write_wait();
2143 /* Wait for response from the remote side. */
2144 type = packet_read();
2146 case SSH_SMSG_SUCCESS:
2149 case SSH_SMSG_FAILURE:
2150 log("Warning: Server denied remote port forwarding.");
2153 /* Unknown packet */
2154 packet_disconnect("Protocol error for port forward request:"
2155 "received packet type %d.", type);
2159 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2160 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2161 permitted_opens[num_permitted_opens].listen_port = listen_port;
2162 num_permitted_opens++;
2167 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2168 * listening for the port, and sends back a success reply (or disconnect
2169 * message if there was an error). This never returns if there was an error.
2173 channel_input_port_forward_request(int is_root, int gateway_ports)
2175 u_short port, host_port;
2178 /* Get arguments from the packet. */
2179 port = packet_get_int();
2180 hostname = packet_get_string(NULL);
2181 host_port = packet_get_int();
2185 * Check that an unprivileged user is not trying to forward a
2188 if (port < IPPORT_RESERVED && !is_root)
2189 packet_disconnect("Requested forwarding of port %d but user is not root.",
2192 /* Initiate forwarding */
2193 channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports);
2195 /* Free the argument string. */
2200 * Permits opening to any host/port if permitted_opens[] is empty. This is
2201 * usually called by the server, because the user could connect to any port
2202 * anyway, and the server has no way to know but to trust the client anyway.
2205 channel_permit_all_opens(void)
2207 if (num_permitted_opens == 0)
2208 all_opens_permitted = 1;
2212 channel_add_permitted_opens(char *host, int port)
2214 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2215 fatal("channel_request_remote_forwarding: too many forwards");
2216 debug("allow port forwarding to host %s port %d", host, port);
2218 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2219 permitted_opens[num_permitted_opens].port_to_connect = port;
2220 num_permitted_opens++;
2222 all_opens_permitted = 0;
2226 channel_clear_permitted_opens(void)
2230 for (i = 0; i < num_permitted_opens; i++)
2231 xfree(permitted_opens[i].host_to_connect);
2232 num_permitted_opens = 0;
2237 /* return socket to remote host, port */
2239 connect_to(const char *host, u_short port)
2241 struct addrinfo hints, *ai, *aitop;
2242 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2246 memset(&hints, 0, sizeof(hints));
2247 hints.ai_family = IPv4or6;
2248 hints.ai_socktype = SOCK_STREAM;
2249 snprintf(strport, sizeof strport, "%d", port);
2250 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2251 error("connect_to %.100s: unknown host (%s)", host,
2252 gai_strerror(gaierr));
2255 for (ai = aitop; ai; ai = ai->ai_next) {
2256 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2258 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2259 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2260 error("connect_to: getnameinfo failed");
2263 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2265 error("socket: %.100s", strerror(errno));
2268 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2269 fatal("connect_to: F_SETFL: %s", strerror(errno));
2270 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2271 errno != EINPROGRESS) {
2272 error("connect_to %.100s port %s: %.100s", ntop, strport,
2275 continue; /* fail -- try next */
2277 break; /* success */
2280 freeaddrinfo(aitop);
2282 error("connect_to %.100s port %d: failed.", host, port);
2291 channel_connect_by_listen_address(u_short listen_port)
2295 for (i = 0; i < num_permitted_opens; i++)
2296 if (permitted_opens[i].listen_port == listen_port)
2298 permitted_opens[i].host_to_connect,
2299 permitted_opens[i].port_to_connect);
2300 error("WARNING: Server requests forwarding for unknown listen_port %d",
2305 /* Check if connecting to that port is permitted and connect. */
2307 channel_connect_to(const char *host, u_short port)
2311 permit = all_opens_permitted;
2313 for (i = 0; i < num_permitted_opens; i++)
2314 if (permitted_opens[i].port_to_connect == port &&
2315 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2320 log("Received request to connect to host %.100s port %d, "
2321 "but the request was denied.", host, port);
2324 return connect_to(host, port);
2327 /* -- X11 forwarding */
2330 * Creates an internet domain socket for listening for X11 connections.
2331 * Returns a suitable display number for the DISPLAY variable, or -1 if
2335 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2336 int single_connection)
2339 int display_number, sock;
2341 struct addrinfo hints, *ai, *aitop;
2342 char strport[NI_MAXSERV];
2343 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2345 for (display_number = x11_display_offset;
2346 display_number < MAX_DISPLAYS;
2348 port = 6000 + display_number;
2349 memset(&hints, 0, sizeof(hints));
2350 hints.ai_family = IPv4or6;
2351 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2352 hints.ai_socktype = SOCK_STREAM;
2353 snprintf(strport, sizeof strport, "%d", port);
2354 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2355 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2358 for (ai = aitop; ai; ai = ai->ai_next) {
2359 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2361 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2363 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2364 error("socket: %.100s", strerror(errno));
2367 debug("x11_create_display_inet: Socket family %d not supported",
2373 if (ai->ai_family == AF_INET6) {
2375 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2376 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2379 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2380 debug("bind port %d: %.100s", port, strerror(errno));
2386 for (n = 0; n < num_socks; n++) {
2392 socks[num_socks++] = sock;
2393 #ifndef DONT_TRY_OTHER_AF
2394 if (num_socks == NUM_SOCKS)
2397 if (x11_use_localhost) {
2398 if (num_socks == NUM_SOCKS)
2405 freeaddrinfo(aitop);
2409 if (display_number >= MAX_DISPLAYS) {
2410 error("Failed to allocate internet-domain X11 display socket.");
2413 /* Start listening for connections on the socket. */
2414 for (n = 0; n < num_socks; n++) {
2416 if (listen(sock, 5) < 0) {
2417 error("listen: %.100s", strerror(errno));
2423 /* Allocate a channel for each socket. */
2424 for (n = 0; n < num_socks; n++) {
2426 nc = channel_new("x11 listener",
2427 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2428 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2429 0, xstrdup("X11 inet listener"), 1);
2430 nc->single_connection = single_connection;
2433 /* Return the display number for the DISPLAY environment variable. */
2434 return display_number;
2438 connect_local_xsocket(u_int dnr)
2441 struct sockaddr_un addr;
2443 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2445 error("socket: %.100s", strerror(errno));
2446 memset(&addr, 0, sizeof(addr));
2447 addr.sun_family = AF_UNIX;
2448 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2449 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2452 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2457 x11_connect_display(void)
2459 int display_number, sock = 0;
2460 const char *display;
2461 char buf[1024], *cp;
2462 struct addrinfo hints, *ai, *aitop;
2463 char strport[NI_MAXSERV];
2466 /* Try to open a socket for the local X server. */
2467 display = getenv("DISPLAY");
2469 error("DISPLAY not set.");
2473 * Now we decode the value of the DISPLAY variable and make a
2474 * connection to the real X server.
2478 * Check if it is a unix domain socket. Unix domain displays are in
2479 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2481 if (strncmp(display, "unix:", 5) == 0 ||
2482 display[0] == ':') {
2483 /* Connect to the unix domain socket. */
2484 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2485 error("Could not parse display number from DISPLAY: %.100s",
2489 /* Create a socket. */
2490 sock = connect_local_xsocket(display_number);
2494 /* OK, we now have a connection to the display. */
2498 * Connect to an inet socket. The DISPLAY value is supposedly
2499 * hostname:d[.s], where hostname may also be numeric IP address.
2501 strlcpy(buf, display, sizeof(buf));
2502 cp = strchr(buf, ':');
2504 error("Could not find ':' in DISPLAY: %.100s", display);
2508 /* buf now contains the host name. But first we parse the display number. */
2509 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2510 error("Could not parse display number from DISPLAY: %.100s",
2515 /* Look up the host address */
2516 memset(&hints, 0, sizeof(hints));
2517 hints.ai_family = IPv4or6;
2518 hints.ai_socktype = SOCK_STREAM;
2519 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2520 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2521 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2524 for (ai = aitop; ai; ai = ai->ai_next) {
2525 /* Create a socket. */
2526 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2528 debug("socket: %.100s", strerror(errno));
2531 /* Connect it to the display. */
2532 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2533 debug("connect %.100s port %d: %.100s", buf,
2534 6000 + display_number, strerror(errno));
2541 freeaddrinfo(aitop);
2543 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2552 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2553 * the remote channel number. We should do whatever we want, and respond
2554 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2558 x11_input_open(int type, u_int32_t seq, void *ctxt)
2561 int remote_id, sock = 0;
2564 debug("Received X11 open request.");
2566 remote_id = packet_get_int();
2568 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2569 remote_host = packet_get_string(NULL);
2571 remote_host = xstrdup("unknown (remote did not supply name)");
2575 /* Obtain a connection to the real X display. */
2576 sock = x11_connect_display();
2578 /* Allocate a channel for this connection. */
2579 c = channel_new("connected x11 socket",
2580 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2582 c->remote_id = remote_id;
2586 /* Send refusal to the remote host. */
2587 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2588 packet_put_int(remote_id);
2590 /* Send a confirmation to the remote host. */
2591 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2592 packet_put_int(remote_id);
2593 packet_put_int(c->self);
2598 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2600 deny_input_open(int type, u_int32_t seq, void *ctxt)
2602 int rchan = packet_get_int();
2604 case SSH_SMSG_AGENT_OPEN:
2605 error("Warning: ssh server tried agent forwarding.");
2607 case SSH_SMSG_X11_OPEN:
2608 error("Warning: ssh server tried X11 forwarding.");
2611 error("deny_input_open: type %d", type);
2614 error("Warning: this is probably a break in attempt by a malicious server.");
2615 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2616 packet_put_int(rchan);
2621 * Requests forwarding of X11 connections, generates fake authentication
2622 * data, and enables authentication spoofing.
2623 * This should be called in the client only.
2626 x11_request_forwarding_with_spoofing(int client_session_id,
2627 const char *proto, const char *data)
2629 u_int data_len = (u_int) strlen(data) / 2;
2630 u_int i, value, len;
2636 cp = getenv("DISPLAY");
2638 cp = strchr(cp, ':');
2640 cp = strchr(cp, '.');
2642 screen_number = atoi(cp + 1);
2646 /* Save protocol name. */
2647 x11_saved_proto = xstrdup(proto);
2650 * Extract real authentication data and generate fake data of the
2653 x11_saved_data = xmalloc(data_len);
2654 x11_fake_data = xmalloc(data_len);
2655 for (i = 0; i < data_len; i++) {
2656 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2657 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2659 rand = arc4random();
2660 x11_saved_data[i] = value;
2661 x11_fake_data[i] = rand & 0xff;
2664 x11_saved_data_len = data_len;
2665 x11_fake_data_len = data_len;
2667 /* Convert the fake data into hex. */
2668 len = 2 * data_len + 1;
2669 new_data = xmalloc(len);
2670 for (i = 0; i < data_len; i++)
2671 snprintf(new_data + 2 * i, len - 2 * i,
2672 "%02x", (u_char) x11_fake_data[i]);
2674 /* Send the request packet. */
2676 channel_request_start(client_session_id, "x11-req", 0);
2677 packet_put_char(0); /* XXX bool single connection */
2679 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2681 packet_put_cstring(proto);
2682 packet_put_cstring(new_data);
2683 packet_put_int(screen_number);
2685 packet_write_wait();
2690 /* -- agent forwarding */
2692 /* Sends a message to the server to request authentication fd forwarding. */
2695 auth_request_forwarding(void)
2697 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2699 packet_write_wait();
2702 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2705 auth_input_open_request(int type, u_int32_t seq, void *ctxt)
2708 int remote_id, sock;
2711 /* Read the remote channel number from the message. */
2712 remote_id = packet_get_int();
2716 * Get a connection to the local authentication agent (this may again
2719 sock = ssh_get_authentication_socket();
2722 * If we could not connect the agent, send an error message back to
2723 * the server. This should never happen unless the agent dies,
2724 * because authentication forwarding is only enabled if we have an
2728 name = xstrdup("authentication agent connection");
2729 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2730 -1, 0, 0, 0, name, 1);
2731 c->remote_id = remote_id;
2735 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2736 packet_put_int(remote_id);
2738 /* Send a confirmation to the remote host. */
2739 debug("Forwarding authentication connection.");
2740 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2741 packet_put_int(remote_id);
2742 packet_put_int(c->self);