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 1.166 2002/02/05 14:32:55 markus Exp $");
57 #include "pathnames.h"
63 * Pointer to an array containing all allocated channels. The array is
64 * dynamically extended as needed.
66 static Channel **channels = NULL;
69 * Size of the channel array. All slots of the array must always be
70 * initialized (at least the type field); unused slots set to NULL
72 static int channels_alloc = 0;
75 * Maximum file descriptor value used in any of the channels. This is
76 * updated in channel_new.
78 static int channel_max_fd = 0;
81 /* -- tcp forwarding */
84 * Data structure for storing which hosts are permitted for forward requests.
85 * The local sides of any remote forwards are stored in this array to prevent
86 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
87 * network (which might be behind a firewall).
90 char *host_to_connect; /* Connect to 'host'. */
91 u_short port_to_connect; /* Connect to 'port'. */
92 u_short listen_port; /* Remote side should listen port number. */
95 /* List of all permitted host/port pairs to connect. */
96 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
98 /* Number of permitted host/port pairs in the array. */
99 static int num_permitted_opens = 0;
101 * If this is true, all opens are permitted. This is the case on the server
102 * on which we have to trust the client anyway, and the user could do
103 * anything after logging in anyway.
105 static int all_opens_permitted = 0;
108 /* -- X11 forwarding */
110 /* Maximum number of fake X11 displays to try. */
111 #define MAX_DISPLAYS 1000
113 /* Saved X11 authentication protocol name. */
114 static char *x11_saved_proto = NULL;
116 /* Saved X11 authentication data. This is the real data. */
117 static char *x11_saved_data = NULL;
118 static u_int x11_saved_data_len = 0;
121 * Fake X11 authentication data. This is what the server will be sending us;
122 * we should replace any occurrences of this by the real data.
124 static char *x11_fake_data = NULL;
125 static u_int x11_fake_data_len;
128 /* -- agent forwarding */
132 /* Name and directory of socket for authentication agent forwarding. */
133 static char *auth_sock_name = NULL;
134 static char *auth_sock_dir = NULL;
136 /* AF_UNSPEC or AF_INET or AF_INET6 */
137 static int IPv4or6 = AF_UNSPEC;
140 static void port_open_helper(Channel *c, char *rtype);
142 /* -- channel core */
145 channel_lookup(int id)
149 if (id < 0 || id > channels_alloc) {
150 log("channel_lookup: %d: bad id", id);
155 log("channel_lookup: %d: bad id: channel free", id);
162 * Register filedescriptors for a channel, used when allocating a channel or
163 * when the channel consumer/producer is ready, e.g. shell exec'd
167 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
168 int extusage, int nonblock)
170 /* Update the maximum file descriptor value. */
171 channel_max_fd = MAX(channel_max_fd, rfd);
172 channel_max_fd = MAX(channel_max_fd, wfd);
173 channel_max_fd = MAX(channel_max_fd, efd);
175 /* XXX set close-on-exec -markus */
179 c->sock = (rfd == wfd) ? rfd : -1;
181 c->extended_usage = extusage;
183 /* XXX ugly hack: nonblock is only set by the server */
184 if (nonblock && isatty(c->rfd)) {
185 debug("channel %d: rfd %d isatty", c->self, c->rfd);
187 if (!isatty(c->wfd)) {
188 error("channel %d: wfd %d is not a tty?",
195 /* enable nonblocking mode */
207 * Allocate a new channel object and set its type and socket. This will cause
208 * remote_name to be freed.
212 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
213 int window, int maxpack, int extusage, char *remote_name, int nonblock)
218 /* Do initial allocation if this is the first call. */
219 if (channels_alloc == 0) {
221 channels = xmalloc(channels_alloc * sizeof(Channel *));
222 for (i = 0; i < channels_alloc; i++)
224 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
226 /* Try to find a free slot where to put the new channel. */
227 for (found = -1, i = 0; i < channels_alloc; i++)
228 if (channels[i] == NULL) {
229 /* Found a free slot. */
234 /* There are no free slots. Take last+1 slot and expand the array. */
235 found = channels_alloc;
236 channels_alloc += 10;
237 debug2("channel: expanding %d", channels_alloc);
238 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
239 for (i = found; i < channels_alloc; i++)
242 /* Initialize and return new channel. */
243 c = channels[found] = xmalloc(sizeof(Channel));
244 memset(c, 0, sizeof(Channel));
245 buffer_init(&c->input);
246 buffer_init(&c->output);
247 buffer_init(&c->extended);
248 c->ostate = CHAN_OUTPUT_OPEN;
249 c->istate = CHAN_INPUT_OPEN;
251 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
255 c->local_window = window;
256 c->local_window_max = window;
257 c->local_consumed = 0;
258 c->local_maxpacket = maxpack;
260 c->remote_name = remote_name;
261 c->remote_window = 0;
262 c->remote_maxpacket = 0;
264 c->single_connection = 0;
265 c->detach_user = NULL;
267 c->input_filter = NULL;
268 debug("channel %d: new [%s]", found, remote_name);
273 channel_find_maxfd(void)
278 for (i = 0; i < channels_alloc; i++) {
281 max = MAX(max, c->rfd);
282 max = MAX(max, c->wfd);
283 max = MAX(max, c->efd);
290 channel_close_fd(int *fdp)
292 int ret = 0, fd = *fdp;
297 if (fd == channel_max_fd)
298 channel_max_fd = channel_find_maxfd();
303 /* Close all channel fd/socket. */
306 channel_close_fds(Channel *c)
308 debug3("channel_close_fds: channel %d: r %d w %d e %d",
309 c->self, c->rfd, c->wfd, c->efd);
311 channel_close_fd(&c->sock);
312 channel_close_fd(&c->rfd);
313 channel_close_fd(&c->wfd);
314 channel_close_fd(&c->efd);
317 /* Free the channel and close its fd/socket. */
320 channel_free(Channel *c)
325 for (n = 0, i = 0; i < channels_alloc; i++)
328 debug("channel_free: channel %d: %s, nchannels %d", c->self,
329 c->remote_name ? c->remote_name : "???", n);
331 s = channel_open_message();
332 debug3("channel_free: status: %s", s);
336 shutdown(c->sock, SHUT_RDWR);
337 channel_close_fds(c);
338 buffer_free(&c->input);
339 buffer_free(&c->output);
340 buffer_free(&c->extended);
341 if (c->remote_name) {
342 xfree(c->remote_name);
343 c->remote_name = NULL;
345 channels[c->self] = NULL;
350 channel_free_all(void)
354 for (i = 0; i < channels_alloc; i++)
355 if (channels[i] != NULL)
356 channel_free(channels[i]);
360 * Closes the sockets/fds of all channels. This is used to close extra file
361 * descriptors after a fork.
365 channel_close_all(void)
369 for (i = 0; i < channels_alloc; i++)
370 if (channels[i] != NULL)
371 channel_close_fds(channels[i]);
375 * Stop listening to channels.
379 channel_stop_listening(void)
384 for (i = 0; i < channels_alloc; i++) {
388 case SSH_CHANNEL_AUTH_SOCKET:
389 case SSH_CHANNEL_PORT_LISTENER:
390 case SSH_CHANNEL_RPORT_LISTENER:
391 case SSH_CHANNEL_X11_LISTENER:
392 channel_close_fd(&c->sock);
401 * Returns true if no channel has too much buffered data, and false if one or
402 * more channel is overfull.
406 channel_not_very_much_buffered_data(void)
411 for (i = 0; i < channels_alloc; i++) {
413 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
416 buffer_len(&c->input) > packet_get_maxsize()) {
417 debug("channel %d: big input buffer %d",
418 c->self, buffer_len(&c->input));
422 if (buffer_len(&c->output) > packet_get_maxsize()) {
423 debug("channel %d: big output buffer %d > %d",
424 c->self, buffer_len(&c->output),
425 packet_get_maxsize());
433 /* Returns true if any channel is still open. */
436 channel_still_open(void)
441 for (i = 0; i < channels_alloc; i++) {
446 case SSH_CHANNEL_X11_LISTENER:
447 case SSH_CHANNEL_PORT_LISTENER:
448 case SSH_CHANNEL_RPORT_LISTENER:
449 case SSH_CHANNEL_CLOSED:
450 case SSH_CHANNEL_AUTH_SOCKET:
451 case SSH_CHANNEL_DYNAMIC:
452 case SSH_CHANNEL_CONNECTING:
453 case SSH_CHANNEL_ZOMBIE:
455 case SSH_CHANNEL_LARVAL:
457 fatal("cannot happen: SSH_CHANNEL_LARVAL");
459 case SSH_CHANNEL_OPENING:
460 case SSH_CHANNEL_OPEN:
461 case SSH_CHANNEL_X11_OPEN:
463 case SSH_CHANNEL_INPUT_DRAINING:
464 case SSH_CHANNEL_OUTPUT_DRAINING:
466 fatal("cannot happen: OUT_DRAIN");
469 fatal("channel_still_open: bad channel type %d", c->type);
476 /* Returns the id of an open channel suitable for keepaliving */
479 channel_find_open(void)
484 for (i = 0; i < channels_alloc; i++) {
489 case SSH_CHANNEL_CLOSED:
490 case SSH_CHANNEL_DYNAMIC:
491 case SSH_CHANNEL_X11_LISTENER:
492 case SSH_CHANNEL_PORT_LISTENER:
493 case SSH_CHANNEL_RPORT_LISTENER:
494 case SSH_CHANNEL_OPENING:
495 case SSH_CHANNEL_CONNECTING:
496 case SSH_CHANNEL_ZOMBIE:
498 case SSH_CHANNEL_LARVAL:
499 case SSH_CHANNEL_AUTH_SOCKET:
500 case SSH_CHANNEL_OPEN:
501 case SSH_CHANNEL_X11_OPEN:
503 case SSH_CHANNEL_INPUT_DRAINING:
504 case SSH_CHANNEL_OUTPUT_DRAINING:
506 fatal("cannot happen: OUT_DRAIN");
509 fatal("channel_find_open: bad channel type %d", c->type);
518 * Returns a message describing the currently open forwarded connections,
519 * suitable for sending to the client. The message contains crlf pairs for
524 channel_open_message(void)
531 buffer_init(&buffer);
532 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
533 buffer_append(&buffer, buf, strlen(buf));
534 for (i = 0; i < channels_alloc; i++) {
539 case SSH_CHANNEL_X11_LISTENER:
540 case SSH_CHANNEL_PORT_LISTENER:
541 case SSH_CHANNEL_RPORT_LISTENER:
542 case SSH_CHANNEL_CLOSED:
543 case SSH_CHANNEL_AUTH_SOCKET:
544 case SSH_CHANNEL_ZOMBIE:
546 case SSH_CHANNEL_LARVAL:
547 case SSH_CHANNEL_OPENING:
548 case SSH_CHANNEL_CONNECTING:
549 case SSH_CHANNEL_DYNAMIC:
550 case SSH_CHANNEL_OPEN:
551 case SSH_CHANNEL_X11_OPEN:
552 case SSH_CHANNEL_INPUT_DRAINING:
553 case SSH_CHANNEL_OUTPUT_DRAINING:
554 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
555 c->self, c->remote_name,
556 c->type, c->remote_id,
557 c->istate, buffer_len(&c->input),
558 c->ostate, buffer_len(&c->output),
560 buffer_append(&buffer, buf, strlen(buf));
563 fatal("channel_open_message: bad channel type %d", c->type);
567 buffer_append(&buffer, "\0", 1);
568 cp = xstrdup(buffer_ptr(&buffer));
569 buffer_free(&buffer);
574 channel_send_open(int id)
576 Channel *c = channel_lookup(id);
578 log("channel_send_open: %d: bad id", id);
581 debug("send channel open %d", id);
582 packet_start(SSH2_MSG_CHANNEL_OPEN);
583 packet_put_cstring(c->ctype);
584 packet_put_int(c->self);
585 packet_put_int(c->local_window);
586 packet_put_int(c->local_maxpacket);
591 channel_request_start(int local_id, char *service, int wantconfirm)
593 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);
609 log("channel_register_comfirm: %d: bad id", id);
615 channel_register_cleanup(int id, channel_callback_fn *fn)
617 Channel *c = channel_lookup(id);
619 log("channel_register_cleanup: %d: bad id", id);
625 channel_cancel_cleanup(int id)
627 Channel *c = channel_lookup(id);
629 log("channel_cancel_cleanup: %d: bad id", id);
632 c->detach_user = NULL;
635 channel_register_filter(int id, channel_filter_fn *fn)
637 Channel *c = channel_lookup(id);
639 log("channel_register_filter: %d: bad id", id);
642 c->input_filter = fn;
646 channel_set_fds(int id, int rfd, int wfd, int efd,
647 int extusage, int nonblock)
649 Channel *c = channel_lookup(id);
650 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
651 fatal("channel_activate for non-larval channel %d.", id);
652 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
653 c->type = SSH_CHANNEL_OPEN;
654 /* XXX window size? */
655 c->local_window = c->local_window_max = c->local_maxpacket * 2;
656 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
657 packet_put_int(c->remote_id);
658 packet_put_int(c->local_window);
663 * 'channel_pre*' are called just before select() to add any bits relevant to
664 * channels in the select bitmasks.
667 * 'channel_post*': perform any appropriate operations for channels which
668 * have events pending.
670 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
671 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
672 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
675 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
677 FD_SET(c->sock, readset);
681 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
683 debug3("channel %d: waiting for connection", c->self);
684 FD_SET(c->sock, writeset);
688 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
690 if (buffer_len(&c->input) < packet_get_maxsize())
691 FD_SET(c->sock, readset);
692 if (buffer_len(&c->output) > 0)
693 FD_SET(c->sock, writeset);
697 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
699 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
701 if (c->istate == CHAN_INPUT_OPEN &&
703 buffer_len(&c->input) < limit)
704 FD_SET(c->rfd, readset);
705 if (c->ostate == CHAN_OUTPUT_OPEN ||
706 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
707 if (buffer_len(&c->output) > 0) {
708 FD_SET(c->wfd, writeset);
709 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
713 /** XXX check close conditions, too */
714 if (compat20 && c->efd != -1) {
715 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
716 buffer_len(&c->extended) > 0)
717 FD_SET(c->efd, writeset);
718 else if (c->extended_usage == CHAN_EXTENDED_READ &&
719 buffer_len(&c->extended) < c->remote_window)
720 FD_SET(c->efd, readset);
725 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
727 if (buffer_len(&c->input) == 0) {
728 packet_start(SSH_MSG_CHANNEL_CLOSE);
729 packet_put_int(c->remote_id);
731 c->type = SSH_CHANNEL_CLOSED;
732 debug("channel %d: closing after input drain.", c->self);
737 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
739 if (buffer_len(&c->output) == 0)
742 FD_SET(c->sock, writeset);
746 * This is a special state for X11 authentication spoofing. An opened X11
747 * connection (when authentication spoofing is being done) remains in this
748 * state until the first packet has been completely read. The authentication
749 * data in that packet is then substituted by the real data if it matches the
750 * fake data, and the channel is put into normal mode.
751 * XXX All this happens at the client side.
752 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
755 x11_open_helper(Buffer *b)
758 u_int proto_len, data_len;
760 /* Check if the fixed size part of the packet is in buffer. */
761 if (buffer_len(b) < 12)
764 /* Parse the lengths of variable-length fields. */
766 if (ucp[0] == 0x42) { /* Byte order MSB first. */
767 proto_len = 256 * ucp[6] + ucp[7];
768 data_len = 256 * ucp[8] + ucp[9];
769 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
770 proto_len = ucp[6] + 256 * ucp[7];
771 data_len = ucp[8] + 256 * ucp[9];
773 debug("Initial X11 packet contains bad byte order byte: 0x%x",
778 /* Check if the whole packet is in buffer. */
780 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
783 /* Check if authentication protocol matches. */
784 if (proto_len != strlen(x11_saved_proto) ||
785 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
786 debug("X11 connection uses different authentication protocol.");
789 /* Check if authentication data matches our fake data. */
790 if (data_len != x11_fake_data_len ||
791 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
792 x11_fake_data, x11_fake_data_len) != 0) {
793 debug("X11 auth data does not match fake data.");
796 /* Check fake data length */
797 if (x11_fake_data_len != x11_saved_data_len) {
798 error("X11 fake_data_len %d != saved_data_len %d",
799 x11_fake_data_len, x11_saved_data_len);
803 * Received authentication protocol and data match
804 * our fake data. Substitute the fake data with real
807 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
808 x11_saved_data, x11_saved_data_len);
813 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
815 int ret = x11_open_helper(&c->output);
817 /* Start normal processing for the channel. */
818 c->type = SSH_CHANNEL_OPEN;
819 channel_pre_open_13(c, readset, writeset);
820 } else if (ret == -1) {
822 * We have received an X11 connection that has bad
823 * authentication information.
825 log("X11 connection rejected because of wrong authentication.");
826 buffer_clear(&c->input);
827 buffer_clear(&c->output);
828 channel_close_fd(&c->sock);
830 c->type = SSH_CHANNEL_CLOSED;
831 packet_start(SSH_MSG_CHANNEL_CLOSE);
832 packet_put_int(c->remote_id);
838 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
840 int ret = x11_open_helper(&c->output);
842 /* c->force_drain = 1; */
845 c->type = SSH_CHANNEL_OPEN;
846 channel_pre_open(c, readset, writeset);
847 } else if (ret == -1) {
848 log("X11 connection rejected because of wrong authentication.");
849 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
851 buffer_clear(&c->input);
853 buffer_clear(&c->output);
854 /* for proto v1, the peer will send an IEOF */
856 chan_write_failed(c);
858 c->type = SSH_CHANNEL_OPEN;
859 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
863 /* try to decode a socks4 header */
865 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
868 int len, have, i, found;
874 struct in_addr dest_addr;
877 debug2("channel %d: decode socks4", c->self);
879 have = buffer_len(&c->input);
880 len = sizeof(s4_req);
883 p = buffer_ptr(&c->input);
884 for (found = 0, i = len; i < have; i++) {
890 /* the peer is probably sending garbage */
891 debug("channel %d: decode socks4: too long",
898 buffer_get(&c->input, (char *)&s4_req.version, 1);
899 buffer_get(&c->input, (char *)&s4_req.command, 1);
900 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
901 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
902 have = buffer_len(&c->input);
903 p = buffer_ptr(&c->input);
905 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
907 fatal("channel %d: decode socks4: len %d > have %d",
909 strlcpy(username, p, sizeof(username));
910 buffer_consume(&c->input, len);
911 buffer_consume(&c->input, 1); /* trailing '\0' */
913 host = inet_ntoa(s4_req.dest_addr);
914 strlcpy(c->path, host, sizeof(c->path));
915 c->host_port = ntohs(s4_req.dest_port);
917 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
918 c->self, host, c->host_port, s4_req.command);
920 if (s4_req.command != 1) {
921 debug("channel %d: cannot handle: socks4 cn %d",
922 c->self, s4_req.command);
925 s4_rsp.version = 0; /* vn: 0 for reply */
926 s4_rsp.command = 90; /* cd: req granted */
927 s4_rsp.dest_port = 0; /* ignored */
928 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
929 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
933 /* dynamic port forwarding */
935 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
940 have = buffer_len(&c->input);
942 debug2("channel %d: pre_dynamic: have %d", c->self, have);
943 /* buffer_dump(&c->input); */
944 /* check if the fixed size part of the packet is in buffer. */
947 FD_SET(c->sock, readset);
950 /* try to guess the protocol */
951 p = buffer_ptr(&c->input);
954 ret = channel_decode_socks4(c, readset, writeset);
962 } else if (ret == 0) {
963 debug2("channel %d: pre_dynamic: need more", c->self);
965 FD_SET(c->sock, readset);
967 /* switch to the next state */
968 c->type = SSH_CHANNEL_OPENING;
969 port_open_helper(c, "direct-tcpip");
973 /* This is our fake X11 server socket. */
975 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
978 struct sockaddr addr;
981 char buf[16384], *remote_ipaddr;
984 if (FD_ISSET(c->sock, readset)) {
985 debug("X11 connection requested.");
986 addrlen = sizeof(addr);
987 newsock = accept(c->sock, &addr, &addrlen);
988 if (c->single_connection) {
989 debug("single_connection: closing X11 listener.");
990 channel_close_fd(&c->sock);
994 error("accept: %.100s", strerror(errno));
997 set_nodelay(newsock);
998 remote_ipaddr = get_peer_ipaddr(newsock);
999 remote_port = get_peer_port(newsock);
1000 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1001 remote_ipaddr, remote_port);
1003 nc = channel_new("accepted x11 socket",
1004 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1005 c->local_window_max, c->local_maxpacket,
1006 0, xstrdup(buf), 1);
1009 xfree(remote_ipaddr);
1013 packet_start(SSH2_MSG_CHANNEL_OPEN);
1014 packet_put_cstring("x11");
1015 packet_put_int(nc->self);
1016 packet_put_int(nc->local_window_max);
1017 packet_put_int(nc->local_maxpacket);
1018 /* originator ipaddr and port */
1019 packet_put_cstring(remote_ipaddr);
1020 if (datafellows & SSH_BUG_X11FWD) {
1021 debug("ssh2 x11 bug compat mode");
1023 packet_put_int(remote_port);
1027 packet_start(SSH_SMSG_X11_OPEN);
1028 packet_put_int(nc->self);
1029 if (packet_get_protocol_flags() &
1030 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1031 packet_put_cstring(buf);
1034 xfree(remote_ipaddr);
1039 port_open_helper(Channel *c, char *rtype)
1043 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1044 u_short remote_port = get_peer_port(c->sock);
1046 direct = (strcmp(rtype, "direct-tcpip") == 0);
1048 snprintf(buf, sizeof buf,
1049 "%s: listening port %d for %.100s port %d, "
1050 "connect from %.200s port %d",
1051 rtype, c->listening_port, c->path, c->host_port,
1052 remote_ipaddr, remote_port);
1054 xfree(c->remote_name);
1055 c->remote_name = xstrdup(buf);
1058 packet_start(SSH2_MSG_CHANNEL_OPEN);
1059 packet_put_cstring(rtype);
1060 packet_put_int(c->self);
1061 packet_put_int(c->local_window_max);
1062 packet_put_int(c->local_maxpacket);
1064 /* target host, port */
1065 packet_put_cstring(c->path);
1066 packet_put_int(c->host_port);
1068 /* listen address, port */
1069 packet_put_cstring(c->path);
1070 packet_put_int(c->listening_port);
1072 /* originator host and port */
1073 packet_put_cstring(remote_ipaddr);
1074 packet_put_int(remote_port);
1077 packet_start(SSH_MSG_PORT_OPEN);
1078 packet_put_int(c->self);
1079 packet_put_cstring(c->path);
1080 packet_put_int(c->host_port);
1081 if (packet_get_protocol_flags() &
1082 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1083 packet_put_cstring(c->remote_name);
1086 xfree(remote_ipaddr);
1090 * This socket is listening for connections to a forwarded TCP/IP port.
1093 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1096 struct sockaddr addr;
1097 int newsock, nextstate;
1101 if (FD_ISSET(c->sock, readset)) {
1102 debug("Connection to port %d forwarding "
1103 "to %.100s port %d requested.",
1104 c->listening_port, c->path, c->host_port);
1106 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1107 nextstate = SSH_CHANNEL_OPENING;
1108 rtype = "forwarded-tcpip";
1110 if (c->host_port == 0) {
1111 nextstate = SSH_CHANNEL_DYNAMIC;
1112 rtype = "dynamic-tcpip";
1114 nextstate = SSH_CHANNEL_OPENING;
1115 rtype = "direct-tcpip";
1119 addrlen = sizeof(addr);
1120 newsock = accept(c->sock, &addr, &addrlen);
1122 error("accept: %.100s", strerror(errno));
1125 nc = channel_new(rtype,
1126 nextstate, newsock, newsock, -1,
1127 c->local_window_max, c->local_maxpacket,
1128 0, xstrdup(rtype), 1);
1130 error("channel_post_port_listener: no new channel:");
1134 nc->listening_port = c->listening_port;
1135 nc->host_port = c->host_port;
1136 strlcpy(nc->path, c->path, sizeof(nc->path));
1138 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1140 * do not call the channel_post handler until
1141 * this flag has been reset by a pre-handler.
1142 * otherwise the FD_ISSET calls might overflow
1146 port_open_helper(nc, rtype);
1152 * This is the authentication agent socket listening for connections from
1156 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1161 struct sockaddr addr;
1164 if (FD_ISSET(c->sock, readset)) {
1165 addrlen = sizeof(addr);
1166 newsock = accept(c->sock, &addr, &addrlen);
1168 error("accept from auth socket: %.100s", strerror(errno));
1171 name = xstrdup("accepted auth socket");
1172 nc = channel_new("accepted auth socket",
1173 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1174 c->local_window_max, c->local_maxpacket,
1177 error("channel_post_auth_listener: channel_new failed");
1182 packet_start(SSH2_MSG_CHANNEL_OPEN);
1183 packet_put_cstring("auth-agent@openssh.com");
1184 packet_put_int(nc->self);
1185 packet_put_int(c->local_window_max);
1186 packet_put_int(c->local_maxpacket);
1188 packet_start(SSH_SMSG_AGENT_OPEN);
1189 packet_put_int(nc->self);
1196 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1199 socklen_t sz = sizeof(err);
1201 if (FD_ISSET(c->sock, writeset)) {
1202 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1205 error("getsockopt SO_ERROR failed");
1208 debug("channel %d: connected", c->self);
1209 c->type = SSH_CHANNEL_OPEN;
1211 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1212 packet_put_int(c->remote_id);
1213 packet_put_int(c->self);
1214 packet_put_int(c->local_window);
1215 packet_put_int(c->local_maxpacket);
1217 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1218 packet_put_int(c->remote_id);
1219 packet_put_int(c->self);
1222 debug("channel %d: not connected: %s",
1223 c->self, strerror(err));
1225 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1226 packet_put_int(c->remote_id);
1227 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1228 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1229 packet_put_cstring(strerror(err));
1230 packet_put_cstring("");
1233 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1234 packet_put_int(c->remote_id);
1243 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1249 FD_ISSET(c->rfd, readset)) {
1250 len = read(c->rfd, buf, sizeof(buf));
1251 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1254 debug("channel %d: read<=0 rfd %d len %d",
1255 c->self, c->rfd, len);
1256 if (c->type != SSH_CHANNEL_OPEN) {
1257 debug("channel %d: not open", c->self);
1260 } else if (compat13) {
1261 buffer_clear(&c->output);
1262 c->type = SSH_CHANNEL_INPUT_DRAINING;
1263 debug("channel %d: input draining.", c->self);
1265 chan_read_failed(c);
1269 if (c->input_filter != NULL) {
1270 if (c->input_filter(c, buf, len) == -1) {
1271 debug("channel %d: filter stops", c->self);
1272 chan_read_failed(c);
1275 buffer_append(&c->input, buf, len);
1281 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1288 /* Send buffered output data to the socket. */
1290 FD_ISSET(c->wfd, writeset) &&
1291 buffer_len(&c->output) > 0) {
1292 data = buffer_ptr(&c->output);
1293 dlen = buffer_len(&c->output);
1294 len = write(c->wfd, data, dlen);
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)
1411 /* Send buffered output data to the socket. */
1412 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1413 len = write(c->sock, buffer_ptr(&c->output),
1414 buffer_len(&c->output));
1416 buffer_clear(&c->output);
1418 buffer_consume(&c->output, len);
1423 channel_handler_init_20(void)
1425 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1426 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1427 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1428 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1429 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1430 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1431 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1432 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1434 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1435 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1436 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1437 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1438 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1439 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1440 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1444 channel_handler_init_13(void)
1446 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1447 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1448 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1449 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1450 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1451 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1452 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1453 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1454 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1456 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1457 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1458 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1459 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1460 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1461 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1462 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1466 channel_handler_init_15(void)
1468 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1469 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1470 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1471 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1472 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1473 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1474 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1476 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1477 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1478 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1479 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1480 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1481 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1485 channel_handler_init(void)
1488 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1489 channel_pre[i] = NULL;
1490 channel_post[i] = NULL;
1493 channel_handler_init_20();
1495 channel_handler_init_13();
1497 channel_handler_init_15();
1500 /* gc dead channels */
1502 channel_garbage_collect(Channel *c)
1506 if (c->detach_user != NULL) {
1507 if (!chan_is_dead(c, 0))
1509 debug("channel %d: gc: notify user", c->self);
1510 c->detach_user(c->self, NULL);
1511 /* if we still have a callback */
1512 if (c->detach_user != NULL)
1514 debug("channel %d: gc: user detached", c->self);
1516 if (!chan_is_dead(c, 1))
1518 debug("channel %d: garbage collecting", c->self);
1523 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1525 static int did_init = 0;
1530 channel_handler_init();
1533 for (i = 0; i < channels_alloc; i++) {
1537 if (ftab[c->type] != NULL)
1538 (*ftab[c->type])(c, readset, writeset);
1539 channel_garbage_collect(c);
1544 * Allocate/update select bitmasks and add any bits relevant to channels in
1548 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1549 int *nallocp, int rekeying)
1554 n = MAX(*maxfdp, channel_max_fd);
1556 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1557 /* perhaps check sz < nalloc/2 and shrink? */
1558 if (*readsetp == NULL || sz > *nallocp) {
1559 *readsetp = xrealloc(*readsetp, sz);
1560 *writesetp = xrealloc(*writesetp, sz);
1564 memset(*readsetp, 0, sz);
1565 memset(*writesetp, 0, sz);
1568 channel_handler(channel_pre, *readsetp, *writesetp);
1572 * After select, perform any appropriate operations for channels which have
1576 channel_after_select(fd_set * readset, fd_set * writeset)
1578 channel_handler(channel_post, readset, writeset);
1582 /* If there is data to send to the connection, enqueue some of it now. */
1585 channel_output_poll(void)
1590 for (i = 0; i < channels_alloc; i++) {
1596 * We are only interested in channels that can have buffered
1600 if (c->type != SSH_CHANNEL_OPEN &&
1601 c->type != SSH_CHANNEL_INPUT_DRAINING)
1604 if (c->type != SSH_CHANNEL_OPEN)
1608 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1609 /* XXX is this true? */
1610 debug3("channel %d: will not send data after close", c->self);
1614 /* Get the amount of buffered data for this channel. */
1615 if ((c->istate == CHAN_INPUT_OPEN ||
1616 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1617 (len = buffer_len(&c->input)) > 0) {
1619 * Send some data for the other side over the secure
1623 if (len > c->remote_window)
1624 len = c->remote_window;
1625 if (len > c->remote_maxpacket)
1626 len = c->remote_maxpacket;
1628 if (packet_is_interactive()) {
1632 /* Keep the packets at reasonable size. */
1633 if (len > packet_get_maxsize()/2)
1634 len = packet_get_maxsize()/2;
1638 packet_start(compat20 ?
1639 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1640 packet_put_int(c->remote_id);
1641 packet_put_string(buffer_ptr(&c->input), len);
1643 buffer_consume(&c->input, len);
1644 c->remote_window -= len;
1646 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1648 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1650 * input-buffer is empty and read-socket shutdown:
1651 * tell peer, that we will not send more data: send IEOF
1655 /* Send extended data, i.e. stderr */
1657 c->remote_window > 0 &&
1658 (len = buffer_len(&c->extended)) > 0 &&
1659 c->extended_usage == CHAN_EXTENDED_READ) {
1660 debug2("channel %d: rwin %d elen %d euse %d",
1661 c->self, c->remote_window, buffer_len(&c->extended),
1663 if (len > c->remote_window)
1664 len = c->remote_window;
1665 if (len > c->remote_maxpacket)
1666 len = c->remote_maxpacket;
1667 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1668 packet_put_int(c->remote_id);
1669 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1670 packet_put_string(buffer_ptr(&c->extended), len);
1672 buffer_consume(&c->extended, len);
1673 c->remote_window -= len;
1674 debug2("channel %d: sent ext data %d", c->self, len);
1680 /* -- protocol input */
1683 channel_input_data(int type, u_int32_t seq, void *ctxt)
1690 /* Get the channel number and verify it. */
1691 id = packet_get_int();
1692 c = channel_lookup(id);
1694 packet_disconnect("Received data for nonexistent channel %d.", id);
1696 /* Ignore any data for non-open channels (might happen on close) */
1697 if (c->type != SSH_CHANNEL_OPEN &&
1698 c->type != SSH_CHANNEL_X11_OPEN)
1701 /* same for protocol 1.5 if output end is no longer open */
1702 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1706 data = packet_get_string(&data_len);
1709 if (data_len > c->local_maxpacket) {
1710 log("channel %d: rcvd big packet %d, maxpack %d",
1711 c->self, data_len, c->local_maxpacket);
1713 if (data_len > c->local_window) {
1714 log("channel %d: rcvd too much data %d, win %d",
1715 c->self, data_len, c->local_window);
1719 c->local_window -= data_len;
1722 buffer_append(&c->output, data, data_len);
1727 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1735 /* Get the channel number and verify it. */
1736 id = packet_get_int();
1737 c = channel_lookup(id);
1740 packet_disconnect("Received extended_data for bad channel %d.", id);
1741 if (c->type != SSH_CHANNEL_OPEN) {
1742 log("channel %d: ext data for non open", id);
1745 tcode = packet_get_int();
1747 c->extended_usage != CHAN_EXTENDED_WRITE ||
1748 tcode != SSH2_EXTENDED_DATA_STDERR) {
1749 log("channel %d: bad ext data", c->self);
1752 data = packet_get_string(&data_len);
1754 if (data_len > c->local_window) {
1755 log("channel %d: rcvd too much extended_data %d, win %d",
1756 c->self, data_len, c->local_window);
1760 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1761 c->local_window -= data_len;
1762 buffer_append(&c->extended, data, data_len);
1767 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1772 id = packet_get_int();
1774 c = channel_lookup(id);
1776 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1779 /* XXX force input close */
1780 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1781 debug("channel %d: FORCE input drain", c->self);
1782 c->istate = CHAN_INPUT_WAIT_DRAIN;
1783 if (buffer_len(&c->input) == 0)
1790 channel_input_close(int type, u_int32_t seq, void *ctxt)
1795 id = packet_get_int();
1797 c = channel_lookup(id);
1799 packet_disconnect("Received close for nonexistent channel %d.", id);
1802 * Send a confirmation that we have closed the channel and no more
1803 * data is coming for it.
1805 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1806 packet_put_int(c->remote_id);
1810 * If the channel is in closed state, we have sent a close request,
1811 * and the other side will eventually respond with a confirmation.
1812 * Thus, we cannot free the channel here, because then there would be
1813 * no-one to receive the confirmation. The channel gets freed when
1814 * the confirmation arrives.
1816 if (c->type != SSH_CHANNEL_CLOSED) {
1818 * Not a closed channel - mark it as draining, which will
1819 * cause it to be freed later.
1821 buffer_clear(&c->input);
1822 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1826 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1828 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
1830 int id = packet_get_int();
1831 Channel *c = channel_lookup(id);
1835 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1836 chan_rcvd_oclose(c);
1840 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
1842 int id = packet_get_int();
1843 Channel *c = channel_lookup(id);
1847 packet_disconnect("Received close confirmation for "
1848 "out-of-range channel %d.", id);
1849 if (c->type != SSH_CHANNEL_CLOSED)
1850 packet_disconnect("Received close confirmation for "
1851 "non-closed channel %d (type %d).", id, c->type);
1856 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
1861 id = packet_get_int();
1862 c = channel_lookup(id);
1864 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1865 packet_disconnect("Received open confirmation for "
1866 "non-opening channel %d.", id);
1867 remote_id = packet_get_int();
1868 /* Record the remote channel number and mark that the channel is now open. */
1869 c->remote_id = remote_id;
1870 c->type = SSH_CHANNEL_OPEN;
1873 c->remote_window = packet_get_int();
1874 c->remote_maxpacket = packet_get_int();
1876 debug2("callback start");
1877 c->confirm(c->self, NULL);
1878 debug2("callback done");
1880 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1881 c->remote_window, c->remote_maxpacket);
1887 reason2txt(int reason)
1890 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1891 return "administratively prohibited";
1892 case SSH2_OPEN_CONNECT_FAILED:
1893 return "connect failed";
1894 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1895 return "unknown channel type";
1896 case SSH2_OPEN_RESOURCE_SHORTAGE:
1897 return "resource shortage";
1899 return "unknown reason";
1903 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
1906 char *msg = NULL, *lang = NULL;
1909 id = packet_get_int();
1910 c = channel_lookup(id);
1912 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1913 packet_disconnect("Received open failure for "
1914 "non-opening channel %d.", id);
1916 reason = packet_get_int();
1917 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1918 msg = packet_get_string(NULL);
1919 lang = packet_get_string(NULL);
1921 log("channel %d: open failed: %s%s%s", id,
1922 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1929 /* Free the channel. This will also close the socket. */
1934 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
1942 /* Get the channel number and verify it. */
1943 id = packet_get_int();
1944 c = channel_lookup(id);
1946 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1947 log("Received window adjust for "
1948 "non-open channel %d.", id);
1951 adjust = packet_get_int();
1953 debug2("channel %d: rcvd adjust %d", id, adjust);
1954 c->remote_window += adjust;
1958 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
1962 char *host, *originator_string;
1963 int remote_id, sock = -1;
1965 remote_id = packet_get_int();
1966 host = packet_get_string(NULL);
1967 host_port = packet_get_int();
1969 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
1970 originator_string = packet_get_string(NULL);
1972 originator_string = xstrdup("unknown (remote did not supply name)");
1975 sock = channel_connect_to(host, host_port);
1977 c = channel_new("connected socket",
1978 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
1979 originator_string, 1);
1981 error("channel_input_port_open: channel_new failed");
1984 c->remote_id = remote_id;
1988 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1989 packet_put_int(remote_id);
1996 /* -- tcp forwarding */
1999 channel_set_af(int af)
2005 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2006 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2009 int success, sock, on = 1;
2010 struct addrinfo hints, *ai, *aitop;
2012 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2013 struct linger linger;
2016 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2017 listen_addr : host_to_connect;
2020 error("No forward host name.");
2023 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2024 error("Forward host name too long.");
2029 * getaddrinfo returns a loopback address if the hostname is
2030 * set to NULL and hints.ai_flags is not AI_PASSIVE
2032 memset(&hints, 0, sizeof(hints));
2033 hints.ai_family = IPv4or6;
2034 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2035 hints.ai_socktype = SOCK_STREAM;
2036 snprintf(strport, sizeof strport, "%d", listen_port);
2037 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2038 packet_disconnect("getaddrinfo: fatal error");
2040 for (ai = aitop; ai; ai = ai->ai_next) {
2041 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2043 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2044 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2045 error("channel_setup_fwd_listener: getnameinfo failed");
2048 /* Create a port to listen for the host. */
2049 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2051 /* this is no error since kernel may not support ipv6 */
2052 verbose("socket: %.100s", strerror(errno));
2056 * Set socket options. We would like the socket to disappear
2057 * as soon as it has been closed for whatever reason.
2059 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2061 linger.l_linger = 5;
2062 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2063 debug("Local forwarding listening on %s port %s.", ntop, strport);
2065 /* Bind the socket to the address. */
2066 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2067 /* address can be in use ipv6 address is already bound */
2069 error("bind: %.100s", strerror(errno));
2071 verbose("bind: %.100s", strerror(errno));
2076 /* Start listening for connections on the socket. */
2077 if (listen(sock, 5) < 0) {
2078 error("listen: %.100s", strerror(errno));
2082 /* Allocate a channel number for the socket. */
2083 c = channel_new("port listener", type, sock, sock, -1,
2084 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2085 0, xstrdup("port listener"), 1);
2087 error("channel_setup_fwd_listener: channel_new failed");
2091 strlcpy(c->path, host, sizeof(c->path));
2092 c->host_port = port_to_connect;
2093 c->listening_port = listen_port;
2097 error("channel_setup_fwd_listener: cannot listen to port: %d",
2099 freeaddrinfo(aitop);
2103 /* protocol local port fwd, used by ssh (and sshd in v1) */
2105 channel_setup_local_fwd_listener(u_short listen_port,
2106 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2108 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2109 NULL, listen_port, host_to_connect, port_to_connect, gateway_ports);
2112 /* protocol v2 remote port fwd, used by sshd */
2114 channel_setup_remote_fwd_listener(const char *listen_address,
2115 u_short listen_port, int gateway_ports)
2117 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2118 listen_address, listen_port, NULL, 0, gateway_ports);
2122 * Initiate forwarding of connections to port "port" on remote host through
2123 * the secure channel to host:port from local side.
2127 channel_request_remote_forwarding(u_short listen_port,
2128 const char *host_to_connect, u_short port_to_connect)
2130 int type, success = 0;
2132 /* Record locally that connection to this host/port is permitted. */
2133 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2134 fatal("channel_request_remote_forwarding: too many forwards");
2136 /* Send the forward request to the remote side. */
2138 const char *address_to_bind = "0.0.0.0";
2139 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2140 packet_put_cstring("tcpip-forward");
2141 packet_put_char(0); /* boolean: want reply */
2142 packet_put_cstring(address_to_bind);
2143 packet_put_int(listen_port);
2145 packet_write_wait();
2146 /* Assume that server accepts the request */
2149 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2150 packet_put_int(listen_port);
2151 packet_put_cstring(host_to_connect);
2152 packet_put_int(port_to_connect);
2154 packet_write_wait();
2156 /* Wait for response from the remote side. */
2157 type = packet_read();
2159 case SSH_SMSG_SUCCESS:
2162 case SSH_SMSG_FAILURE:
2163 log("Warning: Server denied remote port forwarding.");
2166 /* Unknown packet */
2167 packet_disconnect("Protocol error for port forward request:"
2168 "received packet type %d.", type);
2172 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2173 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2174 permitted_opens[num_permitted_opens].listen_port = listen_port;
2175 num_permitted_opens++;
2180 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2181 * listening for the port, and sends back a success reply (or disconnect
2182 * message if there was an error). This never returns if there was an error.
2186 channel_input_port_forward_request(int is_root, int gateway_ports)
2188 u_short port, host_port;
2191 /* Get arguments from the packet. */
2192 port = packet_get_int();
2193 hostname = packet_get_string(NULL);
2194 host_port = packet_get_int();
2198 * Check that an unprivileged user is not trying to forward a
2201 if (port < IPPORT_RESERVED && !is_root)
2202 packet_disconnect("Requested forwarding of port %d but user is not root.",
2205 /* Initiate forwarding */
2206 channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports);
2208 /* Free the argument string. */
2213 * Permits opening to any host/port if permitted_opens[] is empty. This is
2214 * usually called by the server, because the user could connect to any port
2215 * anyway, and the server has no way to know but to trust the client anyway.
2218 channel_permit_all_opens(void)
2220 if (num_permitted_opens == 0)
2221 all_opens_permitted = 1;
2225 channel_add_permitted_opens(char *host, int port)
2227 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2228 fatal("channel_request_remote_forwarding: too many forwards");
2229 debug("allow port forwarding to host %s port %d", host, port);
2231 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2232 permitted_opens[num_permitted_opens].port_to_connect = port;
2233 num_permitted_opens++;
2235 all_opens_permitted = 0;
2239 channel_clear_permitted_opens(void)
2243 for (i = 0; i < num_permitted_opens; i++)
2244 xfree(permitted_opens[i].host_to_connect);
2245 num_permitted_opens = 0;
2250 /* return socket to remote host, port */
2252 connect_to(const char *host, u_short port)
2254 struct addrinfo hints, *ai, *aitop;
2255 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2259 memset(&hints, 0, sizeof(hints));
2260 hints.ai_family = IPv4or6;
2261 hints.ai_socktype = SOCK_STREAM;
2262 snprintf(strport, sizeof strport, "%d", port);
2263 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2264 error("connect_to %.100s: unknown host (%s)", host,
2265 gai_strerror(gaierr));
2268 for (ai = aitop; ai; ai = ai->ai_next) {
2269 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2271 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2272 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2273 error("connect_to: getnameinfo failed");
2276 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2278 error("socket: %.100s", strerror(errno));
2281 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2282 fatal("connect_to: F_SETFL: %s", strerror(errno));
2283 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2284 errno != EINPROGRESS) {
2285 error("connect_to %.100s port %s: %.100s", ntop, strport,
2288 continue; /* fail -- try next */
2290 break; /* success */
2293 freeaddrinfo(aitop);
2295 error("connect_to %.100s port %d: failed.", host, port);
2303 channel_connect_by_listen_address(u_short listen_port)
2307 for (i = 0; i < num_permitted_opens; i++)
2308 if (permitted_opens[i].listen_port == listen_port)
2310 permitted_opens[i].host_to_connect,
2311 permitted_opens[i].port_to_connect);
2312 error("WARNING: Server requests forwarding for unknown listen_port %d",
2317 /* Check if connecting to that port is permitted and connect. */
2319 channel_connect_to(const char *host, u_short port)
2323 permit = all_opens_permitted;
2325 for (i = 0; i < num_permitted_opens; i++)
2326 if (permitted_opens[i].port_to_connect == port &&
2327 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2332 log("Received request to connect to host %.100s port %d, "
2333 "but the request was denied.", host, port);
2336 return connect_to(host, port);
2339 /* -- X11 forwarding */
2342 * Creates an internet domain socket for listening for X11 connections.
2343 * Returns a suitable display number for the DISPLAY variable, or -1 if
2347 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2348 int single_connection)
2351 int display_number, sock;
2353 struct addrinfo hints, *ai, *aitop;
2354 char strport[NI_MAXSERV];
2355 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2357 for (display_number = x11_display_offset;
2358 display_number < MAX_DISPLAYS;
2360 port = 6000 + display_number;
2361 memset(&hints, 0, sizeof(hints));
2362 hints.ai_family = IPv4or6;
2363 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2364 hints.ai_socktype = SOCK_STREAM;
2365 snprintf(strport, sizeof strport, "%d", port);
2366 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2367 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2370 for (ai = aitop; ai; ai = ai->ai_next) {
2371 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2373 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2375 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2376 error("socket: %.100s", strerror(errno));
2379 debug("x11_create_display_inet: Socket family %d not supported",
2384 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2385 debug("bind port %d: %.100s", port, strerror(errno));
2391 for (n = 0; n < num_socks; n++) {
2397 socks[num_socks++] = sock;
2398 #ifndef DONT_TRY_OTHER_AF
2399 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);
2431 nc->single_connection = single_connection;
2434 /* Return the display number for the DISPLAY environment variable. */
2435 return display_number;
2439 connect_local_xsocket(u_int dnr)
2442 struct sockaddr_un addr;
2444 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2446 error("socket: %.100s", strerror(errno));
2447 memset(&addr, 0, sizeof(addr));
2448 addr.sun_family = AF_UNIX;
2449 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2450 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2453 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2458 x11_connect_display(void)
2460 int display_number, sock = 0;
2461 const char *display;
2462 char buf[1024], *cp;
2463 struct addrinfo hints, *ai, *aitop;
2464 char strport[NI_MAXSERV];
2467 /* Try to open a socket for the local X server. */
2468 display = getenv("DISPLAY");
2470 error("DISPLAY not set.");
2474 * Now we decode the value of the DISPLAY variable and make a
2475 * connection to the real X server.
2479 * Check if it is a unix domain socket. Unix domain displays are in
2480 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2482 if (strncmp(display, "unix:", 5) == 0 ||
2483 display[0] == ':') {
2484 /* Connect to the unix domain socket. */
2485 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2486 error("Could not parse display number from DISPLAY: %.100s",
2490 /* Create a socket. */
2491 sock = connect_local_xsocket(display_number);
2495 /* OK, we now have a connection to the display. */
2499 * Connect to an inet socket. The DISPLAY value is supposedly
2500 * hostname:d[.s], where hostname may also be numeric IP address.
2502 strlcpy(buf, display, sizeof(buf));
2503 cp = strchr(buf, ':');
2505 error("Could not find ':' in DISPLAY: %.100s", display);
2509 /* buf now contains the host name. But first we parse the display number. */
2510 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2511 error("Could not parse display number from DISPLAY: %.100s",
2516 /* Look up the host address */
2517 memset(&hints, 0, sizeof(hints));
2518 hints.ai_family = IPv4or6;
2519 hints.ai_socktype = SOCK_STREAM;
2520 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2521 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2522 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2525 for (ai = aitop; ai; ai = ai->ai_next) {
2526 /* Create a socket. */
2527 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2529 debug("socket: %.100s", strerror(errno));
2532 /* Connect it to the display. */
2533 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2534 debug("connect %.100s port %d: %.100s", buf,
2535 6000 + display_number, strerror(errno));
2542 freeaddrinfo(aitop);
2544 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2553 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2554 * the remote channel number. We should do whatever we want, and respond
2555 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2559 x11_input_open(int type, u_int32_t seq, void *ctxt)
2562 int remote_id, sock = 0;
2565 debug("Received X11 open request.");
2567 remote_id = packet_get_int();
2569 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2570 remote_host = packet_get_string(NULL);
2572 remote_host = xstrdup("unknown (remote did not supply name)");
2576 /* Obtain a connection to the real X display. */
2577 sock = x11_connect_display();
2579 /* Allocate a channel for this connection. */
2580 c = channel_new("connected x11 socket",
2581 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2584 error("x11_input_open: channel_new failed");
2587 c->remote_id = remote_id;
2592 /* Send refusal to the remote host. */
2593 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2594 packet_put_int(remote_id);
2596 /* Send a confirmation to the remote host. */
2597 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2598 packet_put_int(remote_id);
2599 packet_put_int(c->self);
2604 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2606 deny_input_open(int type, u_int32_t seq, void *ctxt)
2608 int rchan = packet_get_int();
2610 case SSH_SMSG_AGENT_OPEN:
2611 error("Warning: ssh server tried agent forwarding.");
2613 case SSH_SMSG_X11_OPEN:
2614 error("Warning: ssh server tried X11 forwarding.");
2617 error("deny_input_open: type %d", type);
2620 error("Warning: this is probably a break in attempt by a malicious server.");
2621 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2622 packet_put_int(rchan);
2627 * Requests forwarding of X11 connections, generates fake authentication
2628 * data, and enables authentication spoofing.
2629 * This should be called in the client only.
2632 x11_request_forwarding_with_spoofing(int client_session_id,
2633 const char *proto, const char *data)
2635 u_int data_len = (u_int) strlen(data) / 2;
2636 u_int i, value, len;
2642 cp = getenv("DISPLAY");
2644 cp = strchr(cp, ':');
2646 cp = strchr(cp, '.');
2648 screen_number = atoi(cp + 1);
2652 /* Save protocol name. */
2653 x11_saved_proto = xstrdup(proto);
2656 * Extract real authentication data and generate fake data of the
2659 x11_saved_data = xmalloc(data_len);
2660 x11_fake_data = xmalloc(data_len);
2661 for (i = 0; i < data_len; i++) {
2662 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2663 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2665 rand = arc4random();
2666 x11_saved_data[i] = value;
2667 x11_fake_data[i] = rand & 0xff;
2670 x11_saved_data_len = data_len;
2671 x11_fake_data_len = data_len;
2673 /* Convert the fake data into hex. */
2674 len = 2 * data_len + 1;
2675 new_data = xmalloc(len);
2676 for (i = 0; i < data_len; i++)
2677 snprintf(new_data + 2 * i, len - 2 * i,
2678 "%02x", (u_char) x11_fake_data[i]);
2680 /* Send the request packet. */
2682 channel_request_start(client_session_id, "x11-req", 0);
2683 packet_put_char(0); /* XXX bool single connection */
2685 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2687 packet_put_cstring(proto);
2688 packet_put_cstring(new_data);
2689 packet_put_int(screen_number);
2691 packet_write_wait();
2696 /* -- agent forwarding */
2698 /* Sends a message to the server to request authentication fd forwarding. */
2701 auth_request_forwarding(void)
2703 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2705 packet_write_wait();
2709 * Returns the name of the forwarded authentication socket. Returns NULL if
2710 * there is no forwarded authentication socket. The returned value points to
2715 auth_get_socket_name(void)
2717 return auth_sock_name;
2720 /* removes the agent forwarding socket */
2723 auth_sock_cleanup_proc(void *_pw)
2725 struct passwd *pw = _pw;
2727 if (auth_sock_name) {
2728 temporarily_use_uid(pw);
2729 unlink(auth_sock_name);
2730 rmdir(auth_sock_dir);
2731 auth_sock_name = NULL;
2737 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2738 * This starts forwarding authentication requests.
2742 auth_input_request_forwarding(struct passwd * pw)
2746 struct sockaddr_un sunaddr;
2748 if (auth_get_socket_name() != NULL) {
2749 error("authentication forwarding requested twice.");
2753 /* Temporarily drop privileged uid for mkdir/bind. */
2754 temporarily_use_uid(pw);
2756 /* Allocate a buffer for the socket name, and format the name. */
2757 auth_sock_name = xmalloc(MAXPATHLEN);
2758 auth_sock_dir = xmalloc(MAXPATHLEN);
2759 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2761 /* Create private directory for socket */
2762 if (mkdtemp(auth_sock_dir) == NULL) {
2763 packet_send_debug("Agent forwarding disabled: "
2764 "mkdtemp() failed: %.100s", strerror(errno));
2766 xfree(auth_sock_name);
2767 xfree(auth_sock_dir);
2768 auth_sock_name = NULL;
2769 auth_sock_dir = NULL;
2772 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2773 auth_sock_dir, (int) getpid());
2775 /* delete agent socket on fatal() */
2776 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2778 /* Create the socket. */
2779 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2781 packet_disconnect("socket: %.100s", strerror(errno));
2783 /* Bind it to the name. */
2784 memset(&sunaddr, 0, sizeof(sunaddr));
2785 sunaddr.sun_family = AF_UNIX;
2786 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
2788 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2789 packet_disconnect("bind: %.100s", strerror(errno));
2791 /* Restore the privileged uid. */
2794 /* Start listening on the socket. */
2795 if (listen(sock, 5) < 0)
2796 packet_disconnect("listen: %.100s", strerror(errno));
2798 /* Allocate a channel for the authentication agent socket. */
2799 nc = channel_new("auth socket",
2800 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2801 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2802 0, xstrdup("auth socket"), 1);
2804 error("auth_input_request_forwarding: channel_new failed");
2805 auth_sock_cleanup_proc(pw);
2806 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2810 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2814 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2817 auth_input_open_request(int type, u_int32_t seq, void *ctxt)
2820 int remote_id, sock;
2823 /* Read the remote channel number from the message. */
2824 remote_id = packet_get_int();
2828 * Get a connection to the local authentication agent (this may again
2831 sock = ssh_get_authentication_socket();
2834 * If we could not connect the agent, send an error message back to
2835 * the server. This should never happen unless the agent dies,
2836 * because authentication forwarding is only enabled if we have an
2840 name = xstrdup("authentication agent connection");
2841 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2842 -1, 0, 0, 0, name, 1);
2844 error("auth_input_open_request: channel_new failed");
2848 c->remote_id = remote_id;
2853 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2854 packet_put_int(remote_id);
2856 /* Send a confirmation to the remote host. */
2857 debug("Forwarding authentication connection.");
2858 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2859 packet_put_int(remote_id);
2860 packet_put_int(c->self);