2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
15 * SSH2 support added by Markus Friedl.
16 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved.
17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 RCSID("$OpenBSD: channels.c,v 1.131 2001/07/02 22:52:56 markus Exp $");
62 * Pointer to an array containing all allocated channels. The array is
63 * dynamically extended as needed.
65 static Channel **channels = NULL;
68 * Size of the channel array. All slots of the array must always be
69 * initialized (at least the type field); unused slots set to NULL
71 static int channels_alloc = 0;
74 * Maximum file descriptor value used in any of the channels. This is
75 * updated in channel_new.
77 static int channel_max_fd = 0;
80 /* -- tcp forwarding */
83 * Data structure for storing which hosts are permitted for forward requests.
84 * The local sides of any remote forwards are stored in this array to prevent
85 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
86 * network (which might be behind a firewall).
89 char *host_to_connect; /* Connect to 'host'. */
90 u_short port_to_connect; /* Connect to 'port'. */
91 u_short listen_port; /* Remote side should listen port number. */
94 /* List of all permitted host/port pairs to connect. */
95 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
97 /* Number of permitted host/port pairs in the array. */
98 static int num_permitted_opens = 0;
100 * If this is true, all opens are permitted. This is the case on the server
101 * on which we have to trust the client anyway, and the user could do
102 * anything after logging in anyway.
104 static int all_opens_permitted = 0;
107 /* -- X11 forwarding */
109 /* Maximum number of fake X11 displays to try. */
110 #define MAX_DISPLAYS 1000
112 /* Saved X11 authentication protocol name. */
113 static char *x11_saved_proto = NULL;
115 /* Saved X11 authentication data. This is the real data. */
116 static char *x11_saved_data = NULL;
117 static u_int x11_saved_data_len = 0;
120 * Fake X11 authentication data. This is what the server will be sending us;
121 * we should replace any occurrences of this by the real data.
123 static char *x11_fake_data = NULL;
124 static u_int x11_fake_data_len;
127 /* -- agent forwarding */
131 /* Name and directory of socket for authentication agent forwarding. */
132 static char *auth_sock_name = NULL;
133 static char *auth_sock_dir = NULL;
135 /* AF_UNSPEC or AF_INET or AF_INET6 */
139 static void port_open_helper(Channel *c, char *rtype);
141 /* -- channel core */
144 channel_lookup(int id)
148 if (id < 0 || id > channels_alloc) {
149 log("channel_lookup: %d: bad id", id);
154 log("channel_lookup: %d: bad id: channel free", id);
161 * Register filedescriptors for a channel, used when allocating a channel or
162 * when the channel consumer/producer is ready, e.g. shell exec'd
166 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
167 int extusage, int nonblock)
169 /* Update the maximum file descriptor value. */
170 channel_max_fd = MAX(channel_max_fd, rfd);
171 channel_max_fd = MAX(channel_max_fd, wfd);
172 channel_max_fd = MAX(channel_max_fd, efd);
174 /* XXX set close-on-exec -markus */
178 c->sock = (rfd == wfd) ? rfd : -1;
180 c->extended_usage = extusage;
182 /* XXX ugly hack: nonblock is only set by the server */
183 if (nonblock && isatty(c->rfd)) {
184 debug("channel %d: rfd %d isatty", c->self, c->rfd);
186 if (!isatty(c->wfd)) {
187 error("channel %d: wfd %d is not a tty?",
194 /* enable nonblocking mode */
206 * Allocate a new channel object and set its type and socket. This will cause
207 * remote_name to be freed.
211 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
212 int window, int maxpack, int extusage, char *remote_name, int nonblock)
217 /* Do initial allocation if this is the first call. */
218 if (channels_alloc == 0) {
221 channels = xmalloc(channels_alloc * sizeof(Channel *));
222 for (i = 0; i < channels_alloc; i++)
224 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
226 /* Try to find a free slot where to put the new channel. */
227 for (found = -1, i = 0; i < channels_alloc; i++)
228 if (channels[i] == NULL) {
229 /* Found a free slot. */
234 /* There are no free slots. Take last+1 slot and expand the array. */
235 found = channels_alloc;
236 channels_alloc += 10;
237 debug2("channel: expanding %d", channels_alloc);
238 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
239 for (i = found; i < channels_alloc; i++)
242 /* Initialize and return new channel. */
243 c = channels[found] = xmalloc(sizeof(Channel));
244 buffer_init(&c->input);
245 buffer_init(&c->output);
246 buffer_init(&c->extended);
247 chan_init_iostates(c);
248 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
252 c->local_window = window;
253 c->local_window_max = window;
254 c->local_consumed = 0;
255 c->local_maxpacket = maxpack;
257 c->remote_name = remote_name;
258 c->remote_window = 0;
259 c->remote_maxpacket = 0;
263 c->detach_user = NULL;
264 c->input_filter = NULL;
265 debug("channel %d: new [%s]", found, remote_name);
269 /* Close all channel fd/socket. */
272 channel_close_fds(Channel *c)
274 debug3("channel_close_fds: channel %d: r %d w %d e %d",
275 c->self, c->rfd, c->wfd, c->efd);
295 /* Free the channel and close its fd/socket. */
298 channel_free(Channel *c)
303 for (n = 0, i = 0; i < channels_alloc; i++)
306 debug("channel_free: channel %d: %s, nchannels %d", c->self,
307 c->remote_name ? c->remote_name : "???", n);
309 s = channel_open_message();
310 debug3("channel_free: status: %s", s);
313 if (c->detach_user != NULL) {
314 debug("channel_free: channel %d: detaching channel user", c->self);
315 c->detach_user(c->self, NULL);
318 shutdown(c->sock, SHUT_RDWR);
319 channel_close_fds(c);
320 buffer_free(&c->input);
321 buffer_free(&c->output);
322 buffer_free(&c->extended);
323 if (c->remote_name) {
324 xfree(c->remote_name);
325 c->remote_name = NULL;
327 channels[c->self] = NULL;
332 channel_free_all(void)
336 for (i = 0; i < channels_alloc; i++)
337 if (channels[i] != NULL)
338 channel_free(channels[i]);
342 channel_detach_all(void)
347 for (i = 0; i < channels_alloc; i++) {
349 if (c != NULL && c->detach_user != NULL) {
350 debug("channel_detach_all: channel %d", c->self);
351 c->detach_user(c->self, NULL);
352 c->detach_user = NULL;
358 * Closes the sockets/fds of all channels. This is used to close extra file
359 * descriptors after a fork.
367 for (i = 0; i < channels_alloc; i++)
368 if (channels[i] != NULL)
369 channel_close_fds(channels[i]);
373 * Stop listening to channels.
377 channel_stop_listening(void)
382 for (i = 0; i < channels_alloc; i++) {
386 case SSH_CHANNEL_AUTH_SOCKET:
387 case SSH_CHANNEL_PORT_LISTENER:
388 case SSH_CHANNEL_RPORT_LISTENER:
389 case SSH_CHANNEL_X11_LISTENER:
399 * Returns true if no channel has too much buffered data, and false if one or
400 * more channel is overfull.
404 channel_not_very_much_buffered_data()
409 for (i = 0; i < channels_alloc; i++) {
411 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
412 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
413 debug("channel %d: big input buffer %d",
414 c->self, buffer_len(&c->input));
417 if (buffer_len(&c->output) > packet_get_maxsize()) {
418 debug("channel %d: big output buffer %d",
419 c->self, buffer_len(&c->output));
427 /* Returns true if any channel is still open. */
435 for (i = 0; i < channels_alloc; i++) {
440 case SSH_CHANNEL_X11_LISTENER:
441 case SSH_CHANNEL_PORT_LISTENER:
442 case SSH_CHANNEL_RPORT_LISTENER:
443 case SSH_CHANNEL_CLOSED:
444 case SSH_CHANNEL_AUTH_SOCKET:
445 case SSH_CHANNEL_DYNAMIC:
446 case SSH_CHANNEL_CONNECTING:
447 case SSH_CHANNEL_ZOMBIE:
449 case SSH_CHANNEL_LARVAL:
451 fatal("cannot happen: SSH_CHANNEL_LARVAL");
453 case SSH_CHANNEL_OPENING:
454 case SSH_CHANNEL_OPEN:
455 case SSH_CHANNEL_X11_OPEN:
457 case SSH_CHANNEL_INPUT_DRAINING:
458 case SSH_CHANNEL_OUTPUT_DRAINING:
460 fatal("cannot happen: OUT_DRAIN");
463 fatal("channel_still_open: bad channel type %d", c->type);
470 /* Returns the id of an open channel suitable for keepaliving */
478 for (i = 0; i < channels_alloc; i++) {
483 case SSH_CHANNEL_CLOSED:
484 case SSH_CHANNEL_DYNAMIC:
485 case SSH_CHANNEL_X11_LISTENER:
486 case SSH_CHANNEL_PORT_LISTENER:
487 case SSH_CHANNEL_RPORT_LISTENER:
488 case SSH_CHANNEL_OPENING:
489 case SSH_CHANNEL_CONNECTING:
490 case SSH_CHANNEL_ZOMBIE:
492 case SSH_CHANNEL_LARVAL:
493 case SSH_CHANNEL_AUTH_SOCKET:
494 case SSH_CHANNEL_OPEN:
495 case SSH_CHANNEL_X11_OPEN:
497 case SSH_CHANNEL_INPUT_DRAINING:
498 case SSH_CHANNEL_OUTPUT_DRAINING:
500 fatal("cannot happen: OUT_DRAIN");
503 fatal("channel_find_open: bad channel type %d", c->type);
512 * Returns a message describing the currently open forwarded connections,
513 * suitable for sending to the client. The message contains crlf pairs for
518 channel_open_message()
525 buffer_init(&buffer);
526 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
527 buffer_append(&buffer, buf, strlen(buf));
528 for (i = 0; i < channels_alloc; i++) {
533 case SSH_CHANNEL_X11_LISTENER:
534 case SSH_CHANNEL_PORT_LISTENER:
535 case SSH_CHANNEL_RPORT_LISTENER:
536 case SSH_CHANNEL_CLOSED:
537 case SSH_CHANNEL_AUTH_SOCKET:
538 case SSH_CHANNEL_ZOMBIE:
540 case SSH_CHANNEL_LARVAL:
541 case SSH_CHANNEL_OPENING:
542 case SSH_CHANNEL_CONNECTING:
543 case SSH_CHANNEL_DYNAMIC:
544 case SSH_CHANNEL_OPEN:
545 case SSH_CHANNEL_X11_OPEN:
546 case SSH_CHANNEL_INPUT_DRAINING:
547 case SSH_CHANNEL_OUTPUT_DRAINING:
548 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
549 c->self, c->remote_name,
550 c->type, c->remote_id,
551 c->istate, buffer_len(&c->input),
552 c->ostate, buffer_len(&c->output),
554 buffer_append(&buffer, buf, strlen(buf));
557 fatal("channel_open_message: bad channel type %d", c->type);
561 buffer_append(&buffer, "\0", 1);
562 cp = xstrdup(buffer_ptr(&buffer));
563 buffer_free(&buffer);
568 channel_send_open(int id)
570 Channel *c = channel_lookup(id);
572 log("channel_send_open: %d: bad id", id);
575 debug("send channel open %d", id);
576 packet_start(SSH2_MSG_CHANNEL_OPEN);
577 packet_put_cstring(c->ctype);
578 packet_put_int(c->self);
579 packet_put_int(c->local_window);
580 packet_put_int(c->local_maxpacket);
585 channel_request(int id, char *service, int wantconfirm)
587 channel_request_start(id, service, wantconfirm);
589 debug("channel request %d: %s", id, service) ;
592 channel_request_start(int id, char *service, int wantconfirm)
594 Channel *c = channel_lookup(id);
596 log("channel_request: %d: bad id", id);
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_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
607 Channel *c = channel_lookup(id);
609 log("channel_register_callback: %d: bad id", id);
617 channel_register_cleanup(int id, channel_callback_fn *fn)
619 Channel *c = channel_lookup(id);
621 log("channel_register_cleanup: %d: bad id", id);
627 channel_cancel_cleanup(int id)
629 Channel *c = channel_lookup(id);
631 log("channel_cancel_cleanup: %d: bad id", id);
634 c->detach_user = NULL;
637 channel_register_filter(int id, channel_filter_fn *fn)
639 Channel *c = channel_lookup(id);
641 log("channel_register_filter: %d: bad id", id);
644 c->input_filter = fn;
648 channel_set_fds(int id, int rfd, int wfd, int efd,
649 int extusage, int nonblock)
651 Channel *c = channel_lookup(id);
652 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
653 fatal("channel_activate for non-larval channel %d.", id);
654 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
655 c->type = SSH_CHANNEL_OPEN;
656 /* XXX window size? */
657 c->local_window = c->local_window_max = c->local_maxpacket * 2;
658 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
659 packet_put_int(c->remote_id);
660 packet_put_int(c->local_window);
665 * 'channel_pre*' are called just before select() to add any bits relevant to
666 * channels in the select bitmasks.
669 * 'channel_post*': perform any appropriate operations for channels which
670 * have events pending.
672 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
673 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
674 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
677 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
679 FD_SET(c->sock, readset);
683 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
685 debug3("channel %d: waiting for connection", c->self);
686 FD_SET(c->sock, writeset);
690 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
692 if (buffer_len(&c->input) < packet_get_maxsize())
693 FD_SET(c->sock, readset);
694 if (buffer_len(&c->output) > 0)
695 FD_SET(c->sock, writeset);
699 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
701 /* test whether sockets are 'alive' for read/write */
702 if (c->istate == CHAN_INPUT_OPEN)
703 if (buffer_len(&c->input) < packet_get_maxsize())
704 FD_SET(c->sock, 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->sock, writeset);
709 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
716 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
718 if (c->istate == CHAN_INPUT_OPEN &&
719 c->remote_window > 0 &&
720 buffer_len(&c->input) < c->remote_window)
721 FD_SET(c->rfd, readset);
722 if (c->ostate == CHAN_OUTPUT_OPEN ||
723 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
724 if (buffer_len(&c->output) > 0) {
725 FD_SET(c->wfd, writeset);
726 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
730 /** XXX check close conditions, too */
732 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
733 buffer_len(&c->extended) > 0)
734 FD_SET(c->efd, writeset);
735 else if (c->extended_usage == CHAN_EXTENDED_READ &&
736 buffer_len(&c->extended) < c->remote_window)
737 FD_SET(c->efd, readset);
742 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
744 if (buffer_len(&c->input) == 0) {
745 packet_start(SSH_MSG_CHANNEL_CLOSE);
746 packet_put_int(c->remote_id);
748 c->type = SSH_CHANNEL_CLOSED;
749 debug("channel %d: closing after input drain.", c->self);
754 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
756 if (buffer_len(&c->output) == 0)
759 FD_SET(c->sock, writeset);
763 * This is a special state for X11 authentication spoofing. An opened X11
764 * connection (when authentication spoofing is being done) remains in this
765 * state until the first packet has been completely read. The authentication
766 * data in that packet is then substituted by the real data if it matches the
767 * fake data, and the channel is put into normal mode.
768 * XXX All this happens at the client side.
769 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
772 x11_open_helper(Buffer *b)
775 u_int proto_len, data_len;
777 /* Check if the fixed size part of the packet is in buffer. */
778 if (buffer_len(b) < 12)
781 /* Parse the lengths of variable-length fields. */
782 ucp = (u_char *) buffer_ptr(b);
783 if (ucp[0] == 0x42) { /* Byte order MSB first. */
784 proto_len = 256 * ucp[6] + ucp[7];
785 data_len = 256 * ucp[8] + ucp[9];
786 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
787 proto_len = ucp[6] + 256 * ucp[7];
788 data_len = ucp[8] + 256 * ucp[9];
790 debug("Initial X11 packet contains bad byte order byte: 0x%x",
795 /* Check if the whole packet is in buffer. */
797 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
800 /* Check if authentication protocol matches. */
801 if (proto_len != strlen(x11_saved_proto) ||
802 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
803 debug("X11 connection uses different authentication protocol.");
806 /* Check if authentication data matches our fake data. */
807 if (data_len != x11_fake_data_len ||
808 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
809 x11_fake_data, x11_fake_data_len) != 0) {
810 debug("X11 auth data does not match fake data.");
813 /* Check fake data length */
814 if (x11_fake_data_len != x11_saved_data_len) {
815 error("X11 fake_data_len %d != saved_data_len %d",
816 x11_fake_data_len, x11_saved_data_len);
820 * Received authentication protocol and data match
821 * our fake data. Substitute the fake data with real
824 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
825 x11_saved_data, x11_saved_data_len);
830 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
832 int ret = x11_open_helper(&c->output);
834 /* Start normal processing for the channel. */
835 c->type = SSH_CHANNEL_OPEN;
836 channel_pre_open_13(c, readset, writeset);
837 } else if (ret == -1) {
839 * We have received an X11 connection that has bad
840 * authentication information.
842 log("X11 connection rejected because of wrong authentication.");
843 buffer_clear(&c->input);
844 buffer_clear(&c->output);
847 c->type = SSH_CHANNEL_CLOSED;
848 packet_start(SSH_MSG_CHANNEL_CLOSE);
849 packet_put_int(c->remote_id);
855 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
857 int ret = x11_open_helper(&c->output);
859 c->type = SSH_CHANNEL_OPEN;
861 channel_pre_open_20(c, readset, writeset);
863 channel_pre_open_15(c, readset, writeset);
864 } else if (ret == -1) {
865 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
866 chan_read_failed(c); /** force close? */
867 chan_write_failed(c);
868 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
872 /* try to decode a socks4 header */
874 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
877 int len, have, i, found;
883 struct in_addr dest_addr;
886 debug2("channel %d: decode socks4", c->self);
888 have = buffer_len(&c->input);
889 len = sizeof(s4_req);
892 p = buffer_ptr(&c->input);
893 for (found = 0, i = len; i < have; i++) {
899 /* the peer is probably sending garbage */
900 debug("channel %d: decode socks4: too long",
907 buffer_get(&c->input, (char *)&s4_req.version, 1);
908 buffer_get(&c->input, (char *)&s4_req.command, 1);
909 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
910 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
911 have = buffer_len(&c->input);
912 p = buffer_ptr(&c->input);
914 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
916 fatal("channel %d: decode socks4: len %d > have %d",
918 strlcpy(username, p, sizeof(username));
919 buffer_consume(&c->input, len);
920 buffer_consume(&c->input, 1); /* trailing '\0' */
922 host = inet_ntoa(s4_req.dest_addr);
923 strlcpy(c->path, host, sizeof(c->path));
924 c->host_port = ntohs(s4_req.dest_port);
926 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
927 c->self, host, c->host_port, s4_req.command);
929 if (s4_req.command != 1) {
930 debug("channel %d: cannot handle: socks4 cn %d",
931 c->self, s4_req.command);
934 s4_rsp.version = 0; /* vn: 0 for reply */
935 s4_rsp.command = 90; /* cd: req granted */
936 s4_rsp.dest_port = 0; /* ignored */
937 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
938 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
942 /* dynamic port forwarding */
944 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
949 have = buffer_len(&c->input);
951 debug2("channel %d: pre_dynamic: have %d", c->self, have);
952 /* buffer_dump(&c->input); */
953 /* check if the fixed size part of the packet is in buffer. */
956 FD_SET(c->sock, readset);
959 /* try to guess the protocol */
960 p = buffer_ptr(&c->input);
963 ret = channel_decode_socks4(c, readset, writeset);
971 } else if (ret == 0) {
972 debug2("channel %d: pre_dynamic: need more", c->self);
974 FD_SET(c->sock, readset);
976 /* switch to the next state */
977 c->type = SSH_CHANNEL_OPENING;
978 port_open_helper(c, "direct-tcpip");
982 /* This is our fake X11 server socket. */
984 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
987 struct sockaddr addr;
990 char buf[16384], *remote_ipaddr;
993 if (FD_ISSET(c->sock, readset)) {
994 debug("X11 connection requested.");
995 addrlen = sizeof(addr);
996 newsock = accept(c->sock, &addr, &addrlen);
998 error("accept: %.100s", strerror(errno));
1001 remote_ipaddr = get_peer_ipaddr(newsock);
1002 remote_port = get_peer_port(newsock);
1003 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1004 remote_ipaddr, remote_port);
1006 nc = channel_new("accepted x11 socket",
1007 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1008 c->local_window_max, c->local_maxpacket,
1009 0, xstrdup(buf), 1);
1012 xfree(remote_ipaddr);
1016 packet_start(SSH2_MSG_CHANNEL_OPEN);
1017 packet_put_cstring("x11");
1018 packet_put_int(nc->self);
1019 packet_put_int(c->local_window_max);
1020 packet_put_int(c->local_maxpacket);
1021 /* originator ipaddr and port */
1022 packet_put_cstring(remote_ipaddr);
1023 if (datafellows & SSH_BUG_X11FWD) {
1024 debug("ssh2 x11 bug compat mode");
1026 packet_put_int(remote_port);
1030 packet_start(SSH_SMSG_X11_OPEN);
1031 packet_put_int(nc->self);
1032 if (packet_get_protocol_flags() &
1033 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1034 packet_put_cstring(buf);
1037 xfree(remote_ipaddr);
1042 port_open_helper(Channel *c, char *rtype)
1046 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1047 u_short remote_port = get_peer_port(c->sock);
1049 direct = (strcmp(rtype, "direct-tcpip") == 0);
1051 snprintf(buf, sizeof buf,
1052 "%s: listening port %d for %.100s port %d, "
1053 "connect from %.200s port %d",
1054 rtype, c->listening_port, c->path, c->host_port,
1055 remote_ipaddr, remote_port);
1057 xfree(c->remote_name);
1058 c->remote_name = xstrdup(buf);
1061 packet_start(SSH2_MSG_CHANNEL_OPEN);
1062 packet_put_cstring(rtype);
1063 packet_put_int(c->self);
1064 packet_put_int(c->local_window_max);
1065 packet_put_int(c->local_maxpacket);
1067 /* target host, port */
1068 packet_put_cstring(c->path);
1069 packet_put_int(c->host_port);
1071 /* listen address, port */
1072 packet_put_cstring(c->path);
1073 packet_put_int(c->listening_port);
1075 /* originator host and port */
1076 packet_put_cstring(remote_ipaddr);
1077 packet_put_int(remote_port);
1080 packet_start(SSH_MSG_PORT_OPEN);
1081 packet_put_int(c->self);
1082 packet_put_cstring(c->path);
1083 packet_put_int(c->host_port);
1084 if (packet_get_protocol_flags() &
1085 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1086 packet_put_cstring(c->remote_name);
1089 xfree(remote_ipaddr);
1093 * This socket is listening for connections to a forwarded TCP/IP port.
1096 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1099 struct sockaddr addr;
1100 int newsock, nextstate;
1104 if (FD_ISSET(c->sock, readset)) {
1105 debug("Connection to port %d forwarding "
1106 "to %.100s port %d requested.",
1107 c->listening_port, c->path, c->host_port);
1109 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
1110 "forwarded-tcpip" : "direct-tcpip";
1111 nextstate = (c->host_port == 0 &&
1112 c->type != SSH_CHANNEL_RPORT_LISTENER) ?
1113 SSH_CHANNEL_DYNAMIC : SSH_CHANNEL_OPENING;
1115 addrlen = sizeof(addr);
1116 newsock = accept(c->sock, &addr, &addrlen);
1118 error("accept: %.100s", strerror(errno));
1121 nc = channel_new(rtype,
1122 nextstate, newsock, newsock, -1,
1123 c->local_window_max, c->local_maxpacket,
1124 0, xstrdup(rtype), 1);
1126 error("channel_post_port_listener: no new channel:");
1130 nc->listening_port = c->listening_port;
1131 nc->host_port = c->host_port;
1132 strlcpy(nc->path, c->path, sizeof(nc->path));
1134 if (nextstate != SSH_CHANNEL_DYNAMIC)
1135 port_open_helper(nc, rtype);
1140 * This is the authentication agent socket listening for connections from
1144 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1149 struct sockaddr addr;
1152 if (FD_ISSET(c->sock, readset)) {
1153 addrlen = sizeof(addr);
1154 newsock = accept(c->sock, &addr, &addrlen);
1156 error("accept from auth socket: %.100s", strerror(errno));
1159 name = xstrdup("accepted auth socket");
1160 nc = channel_new("accepted auth socket",
1161 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1162 c->local_window_max, c->local_maxpacket,
1165 error("channel_post_auth_listener: channel_new failed");
1170 packet_start(SSH2_MSG_CHANNEL_OPEN);
1171 packet_put_cstring("auth-agent@openssh.com");
1172 packet_put_int(nc->self);
1173 packet_put_int(c->local_window_max);
1174 packet_put_int(c->local_maxpacket);
1176 packet_start(SSH_SMSG_AGENT_OPEN);
1177 packet_put_int(nc->self);
1184 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1187 socklen_t sz = sizeof(err);
1189 if (FD_ISSET(c->sock, writeset)) {
1190 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1193 error("getsockopt SO_ERROR failed");
1196 debug("channel %d: connected", c->self);
1197 c->type = SSH_CHANNEL_OPEN;
1199 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1200 packet_put_int(c->remote_id);
1201 packet_put_int(c->self);
1202 packet_put_int(c->local_window);
1203 packet_put_int(c->local_maxpacket);
1205 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1206 packet_put_int(c->remote_id);
1207 packet_put_int(c->self);
1210 debug("channel %d: not connected: %s",
1211 c->self, strerror(err));
1213 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1214 packet_put_int(c->remote_id);
1215 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1216 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1217 packet_put_cstring(strerror(err));
1218 packet_put_cstring("");
1221 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1222 packet_put_int(c->remote_id);
1231 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1237 FD_ISSET(c->rfd, readset)) {
1238 len = read(c->rfd, buf, sizeof(buf));
1239 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1242 debug("channel %d: read<=0 rfd %d len %d",
1243 c->self, c->rfd, len);
1244 if (c->type != SSH_CHANNEL_OPEN) {
1245 debug("channel %d: not open", c->self);
1248 } else if (compat13) {
1249 buffer_consume(&c->output, buffer_len(&c->output));
1250 c->type = SSH_CHANNEL_INPUT_DRAINING;
1251 debug("channel %d: input draining.", c->self);
1253 chan_read_failed(c);
1257 if(c->input_filter != NULL) {
1258 if (c->input_filter(c, buf, len) == -1) {
1259 debug("channel %d: filter stops", c->self);
1260 chan_read_failed(c);
1263 buffer_append(&c->input, buf, len);
1269 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1274 /* Send buffered output data to the socket. */
1276 FD_ISSET(c->wfd, writeset) &&
1277 buffer_len(&c->output) > 0) {
1278 len = write(c->wfd, buffer_ptr(&c->output),
1279 buffer_len(&c->output));
1280 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1283 if (c->type != SSH_CHANNEL_OPEN) {
1284 debug("channel %d: not open", c->self);
1287 } else if (compat13) {
1288 buffer_consume(&c->output, buffer_len(&c->output));
1289 debug("channel %d: input draining.", c->self);
1290 c->type = SSH_CHANNEL_INPUT_DRAINING;
1292 chan_write_failed(c);
1296 if (compat20 && c->isatty) {
1297 if (tcgetattr(c->wfd, &tio) == 0 &&
1298 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1300 * Simulate echo to reduce the impact of
1301 * traffic analysis. We need to match the
1302 * size of a SSH2_MSG_CHANNEL_DATA message
1303 * (4 byte channel id + data)
1305 packet_send_ignore(4 + len);
1309 buffer_consume(&c->output, len);
1310 if (compat20 && len > 0) {
1311 c->local_consumed += len;
1317 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1322 /** XXX handle drain efd, too */
1324 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1325 FD_ISSET(c->efd, writeset) &&
1326 buffer_len(&c->extended) > 0) {
1327 len = write(c->efd, buffer_ptr(&c->extended),
1328 buffer_len(&c->extended));
1329 debug2("channel %d: written %d to efd %d",
1330 c->self, len, c->efd);
1331 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1334 debug2("channel %d: closing write-efd %d",
1339 buffer_consume(&c->extended, len);
1340 c->local_consumed += len;
1342 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1343 FD_ISSET(c->efd, readset)) {
1344 len = read(c->efd, buf, sizeof(buf));
1345 debug2("channel %d: read %d from efd %d",
1346 c->self, len, c->efd);
1347 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1350 debug2("channel %d: closing read-efd %d",
1355 buffer_append(&c->extended, buf, len);
1362 channel_check_window(Channel *c)
1364 if (c->type == SSH_CHANNEL_OPEN &&
1365 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1366 c->local_window < c->local_window_max/2 &&
1367 c->local_consumed > 0) {
1368 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1369 packet_put_int(c->remote_id);
1370 packet_put_int(c->local_consumed);
1372 debug2("channel %d: window %d sent adjust %d",
1373 c->self, c->local_window,
1375 c->local_window += c->local_consumed;
1376 c->local_consumed = 0;
1382 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1384 channel_handle_rfd(c, readset, writeset);
1385 channel_handle_wfd(c, readset, writeset);
1389 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1391 channel_handle_rfd(c, readset, writeset);
1392 channel_handle_wfd(c, readset, writeset);
1393 channel_handle_efd(c, readset, writeset);
1395 channel_check_window(c);
1399 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1402 /* Send buffered output data to the socket. */
1403 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1404 len = write(c->sock, buffer_ptr(&c->output),
1405 buffer_len(&c->output));
1407 buffer_consume(&c->output, buffer_len(&c->output));
1409 buffer_consume(&c->output, len);
1414 channel_handler_init_20(void)
1416 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1417 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1418 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1419 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1420 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1421 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1422 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1423 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1425 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1426 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1427 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1428 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1429 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1430 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1431 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1435 channel_handler_init_13(void)
1437 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1438 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1439 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1440 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1441 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1442 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1443 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1444 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1445 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1447 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1448 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1449 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1450 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1451 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1452 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1453 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1457 channel_handler_init_15(void)
1459 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1460 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1461 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1462 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1463 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1464 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1465 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1467 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1468 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1469 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1470 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1471 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1472 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1476 channel_handler_init(void)
1479 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1480 channel_pre[i] = NULL;
1481 channel_post[i] = NULL;
1484 channel_handler_init_20();
1486 channel_handler_init_13();
1488 channel_handler_init_15();
1492 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1494 static int did_init = 0;
1499 channel_handler_init();
1502 for (i = 0; i < channels_alloc; i++) {
1506 if (ftab[c->type] != NULL)
1507 (*ftab[c->type])(c, readset, writeset);
1508 if (chan_is_dead(c)) {
1510 * we have to remove the fd's from the select mask
1511 * before the channels are free'd and the fd's are
1515 FD_CLR(c->wfd, writeset);
1517 FD_CLR(c->rfd, readset);
1519 if (c->extended_usage == CHAN_EXTENDED_READ)
1520 FD_CLR(c->efd, readset);
1521 if (c->extended_usage == CHAN_EXTENDED_WRITE)
1522 FD_CLR(c->efd, writeset);
1530 * Allocate/update select bitmasks and add any bits relevant to channels in
1534 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1540 n = MAX(*maxfdp, channel_max_fd);
1542 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1543 if (*readsetp == NULL || n > *maxfdp) {
1548 *readsetp = xmalloc(sz);
1549 *writesetp = xmalloc(sz);
1552 memset(*readsetp, 0, sz);
1553 memset(*writesetp, 0, sz);
1556 channel_handler(channel_pre, *readsetp, *writesetp);
1560 * After select, perform any appropriate operations for channels which have
1564 channel_after_select(fd_set * readset, fd_set * writeset)
1566 channel_handler(channel_post, readset, writeset);
1570 /* If there is data to send to the connection, enqueue some of it now. */
1573 channel_output_poll()
1578 for (i = 0; i < channels_alloc; i++) {
1584 * We are only interested in channels that can have buffered
1588 if (c->type != SSH_CHANNEL_OPEN &&
1589 c->type != SSH_CHANNEL_INPUT_DRAINING)
1592 if (c->type != SSH_CHANNEL_OPEN)
1596 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1597 /* XXX is this true? */
1598 debug2("channel %d: no data after CLOSE", c->self);
1602 /* Get the amount of buffered data for this channel. */
1603 if ((c->istate == CHAN_INPUT_OPEN ||
1604 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1605 (len = buffer_len(&c->input)) > 0) {
1607 * Send some data for the other side over the secure
1611 if (len > c->remote_window)
1612 len = c->remote_window;
1613 if (len > c->remote_maxpacket)
1614 len = c->remote_maxpacket;
1616 if (packet_is_interactive()) {
1620 /* Keep the packets at reasonable size. */
1621 if (len > packet_get_maxsize()/2)
1622 len = packet_get_maxsize()/2;
1626 packet_start(compat20 ?
1627 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1628 packet_put_int(c->remote_id);
1629 packet_put_string(buffer_ptr(&c->input), len);
1631 buffer_consume(&c->input, len);
1632 c->remote_window -= len;
1634 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1636 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1638 * input-buffer is empty and read-socket shutdown:
1639 * tell peer, that we will not send more data: send IEOF
1643 /* Send extended data, i.e. stderr */
1645 c->remote_window > 0 &&
1646 (len = buffer_len(&c->extended)) > 0 &&
1647 c->extended_usage == CHAN_EXTENDED_READ) {
1648 debug2("channel %d: rwin %d elen %d euse %d",
1649 c->self, c->remote_window, buffer_len(&c->extended),
1651 if (len > c->remote_window)
1652 len = c->remote_window;
1653 if (len > c->remote_maxpacket)
1654 len = c->remote_maxpacket;
1655 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1656 packet_put_int(c->remote_id);
1657 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1658 packet_put_string(buffer_ptr(&c->extended), len);
1660 buffer_consume(&c->extended, len);
1661 c->remote_window -= len;
1662 debug2("channel %d: sent ext data %d", c->self, len);
1668 /* -- protocol input */
1671 channel_input_data(int type, int plen, void *ctxt)
1678 /* Get the channel number and verify it. */
1679 id = packet_get_int();
1680 c = channel_lookup(id);
1682 packet_disconnect("Received data for nonexistent channel %d.", id);
1684 /* Ignore any data for non-open channels (might happen on close) */
1685 if (c->type != SSH_CHANNEL_OPEN &&
1686 c->type != SSH_CHANNEL_X11_OPEN)
1689 /* same for protocol 1.5 if output end is no longer open */
1690 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1694 data = packet_get_string(&data_len);
1698 if (data_len > c->local_maxpacket) {
1699 log("channel %d: rcvd big packet %d, maxpack %d",
1700 c->self, data_len, c->local_maxpacket);
1702 if (data_len > c->local_window) {
1703 log("channel %d: rcvd too much data %d, win %d",
1704 c->self, data_len, c->local_window);
1708 c->local_window -= data_len;
1710 packet_integrity_check(plen, 4 + 4 + data_len, type);
1712 buffer_append(&c->output, data, data_len);
1717 channel_input_extended_data(int type, int plen, 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 tcode = packet_get_int();
1737 c->extended_usage != CHAN_EXTENDED_WRITE ||
1738 tcode != SSH2_EXTENDED_DATA_STDERR) {
1739 log("channel %d: bad ext data", c->self);
1742 data = packet_get_string(&data_len);
1744 if (data_len > c->local_window) {
1745 log("channel %d: rcvd too much extended_data %d, win %d",
1746 c->self, data_len, c->local_window);
1750 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1751 c->local_window -= data_len;
1752 buffer_append(&c->extended, data, data_len);
1757 channel_input_ieof(int type, int plen, void *ctxt)
1762 packet_integrity_check(plen, 4, type);
1764 id = packet_get_int();
1765 c = channel_lookup(id);
1767 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1772 channel_input_close(int type, int plen, void *ctxt)
1777 packet_integrity_check(plen, 4, type);
1779 id = packet_get_int();
1780 c = channel_lookup(id);
1782 packet_disconnect("Received close for nonexistent channel %d.", id);
1785 * Send a confirmation that we have closed the channel and no more
1786 * data is coming for it.
1788 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1789 packet_put_int(c->remote_id);
1793 * If the channel is in closed state, we have sent a close request,
1794 * and the other side will eventually respond with a confirmation.
1795 * Thus, we cannot free the channel here, because then there would be
1796 * no-one to receive the confirmation. The channel gets freed when
1797 * the confirmation arrives.
1799 if (c->type != SSH_CHANNEL_CLOSED) {
1801 * Not a closed channel - mark it as draining, which will
1802 * cause it to be freed later.
1804 buffer_consume(&c->input, buffer_len(&c->input));
1805 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1809 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1811 channel_input_oclose(int type, int plen, void *ctxt)
1813 int id = packet_get_int();
1814 Channel *c = channel_lookup(id);
1815 packet_integrity_check(plen, 4, type);
1817 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1818 chan_rcvd_oclose(c);
1822 channel_input_close_confirmation(int type, int plen, void *ctxt)
1824 int id = packet_get_int();
1825 Channel *c = channel_lookup(id);
1829 packet_disconnect("Received close confirmation for "
1830 "out-of-range channel %d.", id);
1831 if (c->type != SSH_CHANNEL_CLOSED)
1832 packet_disconnect("Received close confirmation for "
1833 "non-closed channel %d (type %d).", id, c->type);
1838 channel_input_open_confirmation(int type, int plen, void *ctxt)
1844 packet_integrity_check(plen, 4 + 4, type);
1846 id = packet_get_int();
1847 c = channel_lookup(id);
1849 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1850 packet_disconnect("Received open confirmation for "
1851 "non-opening channel %d.", id);
1852 remote_id = packet_get_int();
1853 /* Record the remote channel number and mark that the channel is now open. */
1854 c->remote_id = remote_id;
1855 c->type = SSH_CHANNEL_OPEN;
1858 c->remote_window = packet_get_int();
1859 c->remote_maxpacket = packet_get_int();
1861 if (c->cb_fn != NULL && c->cb_event == type) {
1862 debug2("callback start");
1863 c->cb_fn(c->self, c->cb_arg);
1864 debug2("callback done");
1866 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1867 c->remote_window, c->remote_maxpacket);
1872 reason2txt(int reason)
1875 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1876 return "administratively prohibited";
1877 case SSH2_OPEN_CONNECT_FAILED:
1878 return "connect failed";
1879 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1880 return "unknown channel type";
1881 case SSH2_OPEN_RESOURCE_SHORTAGE:
1882 return "resource shortage";
1884 return "unknown reason";
1888 channel_input_open_failure(int type, int plen, void *ctxt)
1891 char *msg = NULL, *lang = NULL;
1895 packet_integrity_check(plen, 4, type);
1897 id = packet_get_int();
1898 c = channel_lookup(id);
1900 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1901 packet_disconnect("Received open failure for "
1902 "non-opening channel %d.", id);
1904 reason = packet_get_int();
1905 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1906 msg = packet_get_string(NULL);
1907 lang = packet_get_string(NULL);
1910 log("channel %d: open failed: %s%s%s", id,
1911 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1917 /* Free the channel. This will also close the socket. */
1922 channel_input_channel_request(int type, int plen, void *ctxt)
1927 id = packet_get_int();
1928 c = channel_lookup(id);
1931 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1932 packet_disconnect("Received request for "
1933 "non-open channel %d.", id);
1934 if (c->cb_fn != NULL && c->cb_event == type) {
1935 debug2("callback start");
1936 c->cb_fn(c->self, c->cb_arg);
1937 debug2("callback done");
1939 char *service = packet_get_string(NULL);
1940 debug("channel %d: rcvd request for %s", c->self, service);
1941 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1947 channel_input_window_adjust(int type, int plen, void *ctxt)
1955 /* Get the channel number and verify it. */
1956 id = packet_get_int();
1957 c = channel_lookup(id);
1959 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1960 log("Received window adjust for "
1961 "non-open channel %d.", id);
1964 adjust = packet_get_int();
1966 debug2("channel %d: rcvd adjust %d", id, adjust);
1967 c->remote_window += adjust;
1971 channel_input_port_open(int type, int plen, void *ctxt)
1975 char *host, *originator_string;
1976 int remote_id, sock = -1;
1978 remote_id = packet_get_int();
1979 host = packet_get_string(NULL);
1980 host_port = packet_get_int();
1982 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
1983 originator_string = packet_get_string(NULL);
1985 originator_string = xstrdup("unknown (remote did not supply name)");
1988 sock = channel_connect_to(host, host_port);
1990 c = channel_new("connected socket",
1991 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
1992 originator_string, 1);
1994 error("channel_input_port_open: channel_new failed");
1997 c->remote_id = remote_id;
2001 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2002 packet_put_int(remote_id);
2009 /* -- tcp forwarding */
2012 * Initiate forwarding of connections to local port "port" through the secure
2013 * channel to host:port from remote side.
2016 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2017 u_short port_to_connect, int gateway_ports)
2019 return channel_request_forwarding(
2021 host_to_connect, port_to_connect,
2022 gateway_ports, /*remote_fwd*/ 0);
2026 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2027 * (SSH_CHANNEL_RPORT_LISTENER).
2030 channel_request_forwarding(
2031 const char *listen_address, u_short listen_port,
2032 const char *host_to_connect, u_short port_to_connect,
2033 int gateway_ports, int remote_fwd)
2036 int success, sock, on = 1, type;
2037 struct addrinfo hints, *ai, *aitop;
2038 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2040 struct linger linger;
2045 host = listen_address;
2046 type = SSH_CHANNEL_RPORT_LISTENER;
2048 host = host_to_connect;
2049 type = SSH_CHANNEL_PORT_LISTENER;
2052 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2053 error("Forward host name too long.");
2057 /* XXX listen_address is currently ignored */
2059 * getaddrinfo returns a loopback address if the hostname is
2060 * set to NULL and hints.ai_flags is not AI_PASSIVE
2062 memset(&hints, 0, sizeof(hints));
2063 hints.ai_family = IPv4or6;
2064 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2065 hints.ai_socktype = SOCK_STREAM;
2066 snprintf(strport, sizeof strport, "%d", listen_port);
2067 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2068 packet_disconnect("getaddrinfo: fatal error");
2070 for (ai = aitop; ai; ai = ai->ai_next) {
2071 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2073 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2074 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2075 error("channel_request_forwarding: getnameinfo failed");
2078 /* Create a port to listen for the host. */
2079 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2081 /* this is no error since kernel may not support ipv6 */
2082 verbose("socket: %.100s", strerror(errno));
2086 * Set socket options. We would like the socket to disappear
2087 * as soon as it has been closed for whatever reason.
2089 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2091 linger.l_linger = 5;
2092 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2093 debug("Local forwarding listening on %s port %s.", ntop, strport);
2095 /* Bind the socket to the address. */
2096 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2097 /* address can be in use ipv6 address is already bound */
2099 error("bind: %.100s", strerror(errno));
2101 verbose("bind: %.100s", strerror(errno));
2106 /* Start listening for connections on the socket. */
2107 if (listen(sock, 5) < 0) {
2108 error("listen: %.100s", strerror(errno));
2112 /* Allocate a channel number for the socket. */
2113 c = channel_new("port listener", type, sock, sock, -1,
2114 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2115 0, xstrdup("port listener"), 1);
2117 error("channel_request_forwarding: channel_new failed");
2121 strlcpy(c->path, host, sizeof(c->path));
2122 c->host_port = port_to_connect;
2123 c->listening_port = listen_port;
2127 error("channel_request_forwarding: cannot listen to port: %d",
2129 freeaddrinfo(aitop);
2134 * Initiate forwarding of connections to port "port" on remote host through
2135 * the secure channel to host:port from local side.
2139 channel_request_remote_forwarding(u_short listen_port,
2140 const char *host_to_connect, u_short port_to_connect)
2142 int payload_len, type, success = 0;
2144 /* Record locally that connection to this host/port is permitted. */
2145 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2146 fatal("channel_request_remote_forwarding: too many forwards");
2148 /* Send the forward request to the remote side. */
2150 const char *address_to_bind = "0.0.0.0";
2151 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2152 packet_put_cstring("tcpip-forward");
2153 packet_put_char(0); /* boolean: want reply */
2154 packet_put_cstring(address_to_bind);
2155 packet_put_int(listen_port);
2157 packet_write_wait();
2158 /* Assume that server accepts the request */
2161 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2162 packet_put_int(listen_port);
2163 packet_put_cstring(host_to_connect);
2164 packet_put_int(port_to_connect);
2166 packet_write_wait();
2168 /* Wait for response from the remote side. */
2169 type = packet_read(&payload_len);
2171 case SSH_SMSG_SUCCESS:
2174 case SSH_SMSG_FAILURE:
2175 log("Warning: Server denied remote port forwarding.");
2178 /* Unknown packet */
2179 packet_disconnect("Protocol error for port forward request:"
2180 "received packet type %d.", type);
2184 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2185 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2186 permitted_opens[num_permitted_opens].listen_port = listen_port;
2187 num_permitted_opens++;
2192 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2193 * listening for the port, and sends back a success reply (or disconnect
2194 * message if there was an error). This never returns if there was an error.
2198 channel_input_port_forward_request(int is_root, int gateway_ports)
2200 u_short port, host_port;
2203 /* Get arguments from the packet. */
2204 port = packet_get_int();
2205 hostname = packet_get_string(NULL);
2206 host_port = packet_get_int();
2210 * Check that an unprivileged user is not trying to forward a
2213 if (port < IPPORT_RESERVED && !is_root)
2214 packet_disconnect("Requested forwarding of port %d but user is not root.",
2217 /* Initiate forwarding */
2218 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2220 /* Free the argument string. */
2225 * Permits opening to any host/port if permitted_opens[] is empty. This is
2226 * usually called by the server, because the user could connect to any port
2227 * anyway, and the server has no way to know but to trust the client anyway.
2230 channel_permit_all_opens()
2232 if (num_permitted_opens == 0)
2233 all_opens_permitted = 1;
2237 channel_add_permitted_opens(char *host, int port)
2239 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2240 fatal("channel_request_remote_forwarding: too many forwards");
2241 debug("allow port forwarding to host %s port %d", host, port);
2243 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2244 permitted_opens[num_permitted_opens].port_to_connect = port;
2245 num_permitted_opens++;
2247 all_opens_permitted = 0;
2251 channel_clear_permitted_opens(void)
2255 for (i = 0; i < num_permitted_opens; i++)
2256 xfree(permitted_opens[i].host_to_connect);
2257 num_permitted_opens = 0;
2262 /* return socket to remote host, port */
2264 connect_to(const char *host, u_short port)
2266 struct addrinfo hints, *ai, *aitop;
2267 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2271 memset(&hints, 0, sizeof(hints));
2272 hints.ai_family = IPv4or6;
2273 hints.ai_socktype = SOCK_STREAM;
2274 snprintf(strport, sizeof strport, "%d", port);
2275 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2276 error("connect_to %.100s: unknown host (%s)", host,
2277 gai_strerror(gaierr));
2280 for (ai = aitop; ai; ai = ai->ai_next) {
2281 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2283 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2284 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2285 error("connect_to: getnameinfo failed");
2288 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2290 error("socket: %.100s", strerror(errno));
2293 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2294 fatal("connect_to: F_SETFL: %s", strerror(errno));
2295 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2296 errno != EINPROGRESS) {
2297 error("connect_to %.100s port %s: %.100s", ntop, strport,
2300 continue; /* fail -- try next */
2302 break; /* success */
2305 freeaddrinfo(aitop);
2307 error("connect_to %.100s port %d: failed.", host, port);
2315 channel_connect_by_listen_address(u_short listen_port)
2319 for (i = 0; i < num_permitted_opens; i++)
2320 if (permitted_opens[i].listen_port == listen_port)
2322 permitted_opens[i].host_to_connect,
2323 permitted_opens[i].port_to_connect);
2324 error("WARNING: Server requests forwarding for unknown listen_port %d",
2329 /* Check if connecting to that port is permitted and connect. */
2331 channel_connect_to(const char *host, u_short port)
2335 permit = all_opens_permitted;
2337 for (i = 0; i < num_permitted_opens; i++)
2338 if (permitted_opens[i].port_to_connect == port &&
2339 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2344 log("Received request to connect to host %.100s port %d, "
2345 "but the request was denied.", host, port);
2348 return connect_to(host, port);
2351 /* -- X11 forwarding */
2354 * Creates an internet domain socket for listening for X11 connections.
2355 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2359 x11_create_display_inet(int screen_number, int x11_display_offset)
2361 int display_number, sock;
2363 struct addrinfo hints, *ai, *aitop;
2364 char strport[NI_MAXSERV];
2365 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2367 char hostname[MAXHOSTNAMELEN];
2369 for (display_number = x11_display_offset;
2370 display_number < MAX_DISPLAYS;
2372 port = 6000 + display_number;
2373 memset(&hints, 0, sizeof(hints));
2374 hints.ai_family = IPv4or6;
2375 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2376 hints.ai_socktype = SOCK_STREAM;
2377 snprintf(strport, sizeof strport, "%d", port);
2378 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2379 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2382 for (ai = aitop; ai; ai = ai->ai_next) {
2383 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2385 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2387 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2388 error("socket: %.100s", strerror(errno));
2391 debug("x11_create_display_inet: Socket family %d not supported",
2396 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2397 debug("bind port %d: %.100s", port, strerror(errno));
2398 shutdown(sock, SHUT_RDWR);
2404 for (n = 0; n < num_socks; n++) {
2405 shutdown(socks[n], SHUT_RDWR);
2411 socks[num_socks++] = sock;
2412 #ifndef DONT_TRY_OTHER_AF
2413 if (num_socks == NUM_SOCKS)
2419 freeaddrinfo(aitop);
2423 if (display_number >= MAX_DISPLAYS) {
2424 error("Failed to allocate internet-domain X11 display socket.");
2427 /* Start listening for connections on the socket. */
2428 for (n = 0; n < num_socks; n++) {
2430 if (listen(sock, 5) < 0) {
2431 error("listen: %.100s", strerror(errno));
2432 shutdown(sock, SHUT_RDWR);
2438 /* Set up a suitable value for the DISPLAY variable. */
2439 if (gethostname(hostname, sizeof(hostname)) < 0)
2440 fatal("gethostname: %.100s", strerror(errno));
2442 #ifdef IPADDR_IN_DISPLAY
2444 * HPUX detects the local hostname in the DISPLAY variable and tries
2445 * to set up a shared memory connection to the server, which it
2446 * incorrectly supposes to be local.
2448 * The workaround - as used in later $$H and other programs - is
2449 * is to set display to the host's IP address.
2453 struct in_addr my_addr;
2455 he = gethostbyname(hostname);
2457 error("[X11-broken-fwd-hostname-workaround] Could not get "
2458 "IP address for hostname %s.", hostname);
2460 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2461 "Could not get IP address for hostname %s.", hostname);
2463 shutdown(sock, SHUT_RDWR);
2469 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2471 /* Set DISPLAY to <ip address>:screen.display */
2472 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2473 display_number, screen_number);
2475 #else /* IPADDR_IN_DISPLAY */
2476 /* Just set DISPLAY to hostname:screen.display */
2477 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2478 display_number, screen_number);
2479 #endif /* IPADDR_IN_DISPLAY */
2481 /* Allocate a channel for each socket. */
2482 for (n = 0; n < num_socks; n++) {
2484 (void) channel_new("x11 listener",
2485 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2486 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2487 0, xstrdup("X11 inet listener"), 1);
2490 /* Return a suitable value for the DISPLAY environment variable. */
2491 return xstrdup(display);
2495 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2499 connect_local_xsocket(u_int dnr)
2501 static const char *const x_sockets[] = {
2503 "/var/X/.X11-unix/X" "%u",
2504 "/usr/spool/sockets/X11/" "%u",
2508 struct sockaddr_un addr;
2509 const char *const * path;
2511 for (path = x_sockets; *path; ++path) {
2512 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2514 error("socket: %.100s", strerror(errno));
2515 memset(&addr, 0, sizeof(addr));
2516 addr.sun_family = AF_UNIX;
2517 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2518 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2522 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2527 x11_connect_display(void)
2529 int display_number, sock = 0;
2530 const char *display;
2531 char buf[1024], *cp;
2532 struct addrinfo hints, *ai, *aitop;
2533 char strport[NI_MAXSERV];
2536 /* Try to open a socket for the local X server. */
2537 display = getenv("DISPLAY");
2539 error("DISPLAY not set.");
2543 * Now we decode the value of the DISPLAY variable and make a
2544 * connection to the real X server.
2548 * Check if it is a unix domain socket. Unix domain displays are in
2549 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2551 if (strncmp(display, "unix:", 5) == 0 ||
2552 display[0] == ':') {
2553 /* Connect to the unix domain socket. */
2554 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2555 error("Could not parse display number from DISPLAY: %.100s",
2559 /* Create a socket. */
2560 sock = connect_local_xsocket(display_number);
2564 /* OK, we now have a connection to the display. */
2568 * Connect to an inet socket. The DISPLAY value is supposedly
2569 * hostname:d[.s], where hostname may also be numeric IP address.
2571 strncpy(buf, display, sizeof(buf));
2572 buf[sizeof(buf) - 1] = 0;
2573 cp = strchr(buf, ':');
2575 error("Could not find ':' in DISPLAY: %.100s", display);
2579 /* buf now contains the host name. But first we parse the display number. */
2580 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2581 error("Could not parse display number from DISPLAY: %.100s",
2586 /* Look up the host address */
2587 memset(&hints, 0, sizeof(hints));
2588 hints.ai_family = IPv4or6;
2589 hints.ai_socktype = SOCK_STREAM;
2590 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2591 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2592 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2595 for (ai = aitop; ai; ai = ai->ai_next) {
2596 /* Create a socket. */
2597 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2599 debug("socket: %.100s", strerror(errno));
2602 /* Connect it to the display. */
2603 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2604 debug("connect %.100s port %d: %.100s", buf,
2605 6000 + display_number, strerror(errno));
2612 freeaddrinfo(aitop);
2614 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2622 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2623 * the remote channel number. We should do whatever we want, and respond
2624 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2628 x11_input_open(int type, int plen, void *ctxt)
2631 int remote_id, sock = 0;
2634 debug("Received X11 open request.");
2636 remote_id = packet_get_int();
2638 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2639 remote_host = packet_get_string(NULL);
2641 remote_host = xstrdup("unknown (remote did not supply name)");
2645 /* Obtain a connection to the real X display. */
2646 sock = x11_connect_display();
2648 /* Allocate a channel for this connection. */
2649 c = channel_new("connected x11 socket",
2650 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2653 error("x11_input_open: channel_new failed");
2656 c->remote_id = remote_id;
2660 /* Send refusal to the remote host. */
2661 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2662 packet_put_int(remote_id);
2664 /* Send a confirmation to the remote host. */
2665 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2666 packet_put_int(remote_id);
2667 packet_put_int(c->self);
2672 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2674 deny_input_open(int type, int plen, void *ctxt)
2676 int rchan = packet_get_int();
2678 case SSH_SMSG_AGENT_OPEN:
2679 error("Warning: ssh server tried agent forwarding.");
2681 case SSH_SMSG_X11_OPEN:
2682 error("Warning: ssh server tried X11 forwarding.");
2685 error("deny_input_open: type %d plen %d", type, plen);
2688 error("Warning: this is probably a break in attempt by a malicious server.");
2689 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2690 packet_put_int(rchan);
2695 * Requests forwarding of X11 connections, generates fake authentication
2696 * data, and enables authentication spoofing.
2697 * This should be called in the client only.
2700 x11_request_forwarding_with_spoofing(int client_session_id,
2701 const char *proto, const char *data)
2703 u_int data_len = (u_int) strlen(data) / 2;
2704 u_int i, value, len;
2710 cp = getenv("DISPLAY");
2712 cp = strchr(cp, ':');
2714 cp = strchr(cp, '.');
2716 screen_number = atoi(cp + 1);
2720 /* Save protocol name. */
2721 x11_saved_proto = xstrdup(proto);
2724 * Extract real authentication data and generate fake data of the
2727 x11_saved_data = xmalloc(data_len);
2728 x11_fake_data = xmalloc(data_len);
2729 for (i = 0; i < data_len; i++) {
2730 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2731 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2733 rand = arc4random();
2734 x11_saved_data[i] = value;
2735 x11_fake_data[i] = rand & 0xff;
2738 x11_saved_data_len = data_len;
2739 x11_fake_data_len = data_len;
2741 /* Convert the fake data into hex. */
2742 len = 2 * data_len + 1;
2743 new_data = xmalloc(len);
2744 for (i = 0; i < data_len; i++)
2745 snprintf(new_data + 2 * i, len - 2 * i,
2746 "%02x", (u_char) x11_fake_data[i]);
2748 /* Send the request packet. */
2750 channel_request_start(client_session_id, "x11-req", 0);
2751 packet_put_char(0); /* XXX bool single connection */
2753 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2755 packet_put_cstring(proto);
2756 packet_put_cstring(new_data);
2757 packet_put_int(screen_number);
2759 packet_write_wait();
2764 /* -- agent forwarding */
2766 /* Sends a message to the server to request authentication fd forwarding. */
2769 auth_request_forwarding()
2771 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2773 packet_write_wait();
2777 * Returns the name of the forwarded authentication socket. Returns NULL if
2778 * there is no forwarded authentication socket. The returned value points to
2783 auth_get_socket_name()
2785 return auth_sock_name;
2788 /* removes the agent forwarding socket */
2791 auth_sock_cleanup_proc(void *_pw)
2793 struct passwd *pw = _pw;
2795 if (auth_sock_name) {
2796 temporarily_use_uid(pw);
2797 unlink(auth_sock_name);
2798 rmdir(auth_sock_dir);
2799 auth_sock_name = NULL;
2805 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2806 * This starts forwarding authentication requests.
2810 auth_input_request_forwarding(struct passwd * pw)
2814 struct sockaddr_un sunaddr;
2816 if (auth_get_socket_name() != NULL) {
2817 error("authentication forwarding requested twice.");
2821 /* Temporarily drop privileged uid for mkdir/bind. */
2822 temporarily_use_uid(pw);
2824 /* Allocate a buffer for the socket name, and format the name. */
2825 auth_sock_name = xmalloc(MAXPATHLEN);
2826 auth_sock_dir = xmalloc(MAXPATHLEN);
2827 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2829 /* Create private directory for socket */
2830 if (mkdtemp(auth_sock_dir) == NULL) {
2831 packet_send_debug("Agent forwarding disabled: "
2832 "mkdtemp() failed: %.100s", strerror(errno));
2834 xfree(auth_sock_name);
2835 xfree(auth_sock_dir);
2836 auth_sock_name = NULL;
2837 auth_sock_dir = NULL;
2840 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2841 auth_sock_dir, (int) getpid());
2843 /* delete agent socket on fatal() */
2844 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2846 /* Create the socket. */
2847 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2849 packet_disconnect("socket: %.100s", strerror(errno));
2851 /* Bind it to the name. */
2852 memset(&sunaddr, 0, sizeof(sunaddr));
2853 sunaddr.sun_family = AF_UNIX;
2854 strncpy(sunaddr.sun_path, auth_sock_name,
2855 sizeof(sunaddr.sun_path));
2857 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2858 packet_disconnect("bind: %.100s", strerror(errno));
2860 /* Restore the privileged uid. */
2863 /* Start listening on the socket. */
2864 if (listen(sock, 5) < 0)
2865 packet_disconnect("listen: %.100s", strerror(errno));
2867 /* Allocate a channel for the authentication agent socket. */
2868 nc = channel_new("auth socket",
2869 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2870 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2871 0, xstrdup("auth socket"), 1);
2873 error("auth_input_request_forwarding: channel_new failed");
2874 auth_sock_cleanup_proc(pw);
2875 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2879 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2883 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2886 auth_input_open_request(int type, int plen, void *ctxt)
2889 int remote_id, sock;
2892 packet_integrity_check(plen, 4, type);
2894 /* Read the remote channel number from the message. */
2895 remote_id = packet_get_int();
2898 * Get a connection to the local authentication agent (this may again
2901 sock = ssh_get_authentication_socket();
2904 * If we could not connect the agent, send an error message back to
2905 * the server. This should never happen unless the agent dies,
2906 * because authentication forwarding is only enabled if we have an
2910 name = xstrdup("authentication agent connection");
2911 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2912 -1, 0, 0, 0, name, 1);
2914 error("auth_input_open_request: channel_new failed");
2918 c->remote_id = remote_id;
2922 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2923 packet_put_int(remote_id);
2925 /* Send a confirmation to the remote host. */
2926 debug("Forwarding authentication connection.");
2927 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2928 packet_put_int(remote_id);
2929 packet_put_int(c->self);