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 1.153 2001/12/28 14:50:54 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) {
222 channels = xmalloc(channels_alloc * sizeof(Channel *));
223 for (i = 0; i < channels_alloc; i++)
225 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
227 /* Try to find a free slot where to put the new channel. */
228 for (found = -1, i = 0; i < channels_alloc; i++)
229 if (channels[i] == NULL) {
230 /* Found a free slot. */
235 /* There are no free slots. Take last+1 slot and expand the array. */
236 found = channels_alloc;
237 channels_alloc += 10;
238 debug2("channel: expanding %d", channels_alloc);
239 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
240 for (i = found; i < channels_alloc; i++)
243 /* Initialize and return new channel. */
244 c = channels[found] = xmalloc(sizeof(Channel));
245 memset(c, 0, sizeof(Channel));
246 buffer_init(&c->input);
247 buffer_init(&c->output);
248 buffer_init(&c->extended);
249 chan_init_iostates(c);
250 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
254 c->local_window = window;
255 c->local_window_max = window;
256 c->local_consumed = 0;
257 c->local_maxpacket = maxpack;
259 c->remote_name = remote_name;
260 c->remote_window = 0;
261 c->remote_maxpacket = 0;
266 c->single_connection = 0;
267 c->detach_user = NULL;
268 c->input_filter = NULL;
269 debug("channel %d: new [%s]", found, remote_name);
274 channel_find_maxfd(void)
279 for (i = 0; i < channels_alloc; i++) {
282 max = MAX(max, c->rfd);
283 max = MAX(max, c->wfd);
284 max = MAX(max, c->efd);
291 channel_close_fd(int *fdp)
293 int ret = 0, fd = *fdp;
298 if (fd == channel_max_fd)
299 channel_max_fd = channel_find_maxfd();
304 /* Close all channel fd/socket. */
307 channel_close_fds(Channel *c)
309 debug3("channel_close_fds: channel %d: r %d w %d e %d",
310 c->self, c->rfd, c->wfd, c->efd);
312 channel_close_fd(&c->sock);
313 channel_close_fd(&c->rfd);
314 channel_close_fd(&c->wfd);
315 channel_close_fd(&c->efd);
318 /* Free the channel and close its fd/socket. */
321 channel_free(Channel *c)
326 for (n = 0, i = 0; i < channels_alloc; i++)
329 debug("channel_free: channel %d: %s, nchannels %d", c->self,
330 c->remote_name ? c->remote_name : "???", n);
332 s = channel_open_message();
333 debug3("channel_free: status: %s", s);
337 shutdown(c->sock, SHUT_RDWR);
338 channel_close_fds(c);
339 buffer_free(&c->input);
340 buffer_free(&c->output);
341 buffer_free(&c->extended);
342 if (c->remote_name) {
343 xfree(c->remote_name);
344 c->remote_name = NULL;
346 channels[c->self] = NULL;
351 channel_free_all(void)
355 for (i = 0; i < channels_alloc; i++)
356 if (channels[i] != NULL)
357 channel_free(channels[i]);
361 * Closes the sockets/fds of all channels. This is used to close extra file
362 * descriptors after a fork.
366 channel_close_all(void)
370 for (i = 0; i < channels_alloc; i++)
371 if (channels[i] != NULL)
372 channel_close_fds(channels[i]);
376 * Stop listening to channels.
380 channel_stop_listening(void)
385 for (i = 0; i < channels_alloc; i++) {
389 case SSH_CHANNEL_AUTH_SOCKET:
390 case SSH_CHANNEL_PORT_LISTENER:
391 case SSH_CHANNEL_RPORT_LISTENER:
392 case SSH_CHANNEL_X11_LISTENER:
393 channel_close_fd(&c->sock);
402 * Returns true if no channel has too much buffered data, and false if one or
403 * more channel is overfull.
407 channel_not_very_much_buffered_data(void)
412 for (i = 0; i < channels_alloc; i++) {
414 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
417 buffer_len(&c->input) > packet_get_maxsize()) {
418 debug("channel %d: big input buffer %d",
419 c->self, buffer_len(&c->input));
423 if (buffer_len(&c->output) > packet_get_maxsize()) {
424 debug("channel %d: big output buffer %d > %d",
425 c->self, buffer_len(&c->output),
426 packet_get_maxsize());
434 /* Returns true if any channel is still open. */
437 channel_still_open(void)
442 for (i = 0; i < channels_alloc; i++) {
447 case SSH_CHANNEL_X11_LISTENER:
448 case SSH_CHANNEL_PORT_LISTENER:
449 case SSH_CHANNEL_RPORT_LISTENER:
450 case SSH_CHANNEL_CLOSED:
451 case SSH_CHANNEL_AUTH_SOCKET:
452 case SSH_CHANNEL_DYNAMIC:
453 case SSH_CHANNEL_CONNECTING:
454 case SSH_CHANNEL_ZOMBIE:
456 case SSH_CHANNEL_LARVAL:
458 fatal("cannot happen: SSH_CHANNEL_LARVAL");
460 case SSH_CHANNEL_OPENING:
461 case SSH_CHANNEL_OPEN:
462 case SSH_CHANNEL_X11_OPEN:
464 case SSH_CHANNEL_INPUT_DRAINING:
465 case SSH_CHANNEL_OUTPUT_DRAINING:
467 fatal("cannot happen: OUT_DRAIN");
470 fatal("channel_still_open: bad channel type %d", c->type);
477 /* Returns the id of an open channel suitable for keepaliving */
480 channel_find_open(void)
485 for (i = 0; i < channels_alloc; i++) {
490 case SSH_CHANNEL_CLOSED:
491 case SSH_CHANNEL_DYNAMIC:
492 case SSH_CHANNEL_X11_LISTENER:
493 case SSH_CHANNEL_PORT_LISTENER:
494 case SSH_CHANNEL_RPORT_LISTENER:
495 case SSH_CHANNEL_OPENING:
496 case SSH_CHANNEL_CONNECTING:
497 case SSH_CHANNEL_ZOMBIE:
499 case SSH_CHANNEL_LARVAL:
500 case SSH_CHANNEL_AUTH_SOCKET:
501 case SSH_CHANNEL_OPEN:
502 case SSH_CHANNEL_X11_OPEN:
504 case SSH_CHANNEL_INPUT_DRAINING:
505 case SSH_CHANNEL_OUTPUT_DRAINING:
507 fatal("cannot happen: OUT_DRAIN");
510 fatal("channel_find_open: bad channel type %d", c->type);
519 * Returns a message describing the currently open forwarded connections,
520 * suitable for sending to the client. The message contains crlf pairs for
525 channel_open_message(void)
532 buffer_init(&buffer);
533 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
534 buffer_append(&buffer, buf, strlen(buf));
535 for (i = 0; i < channels_alloc; i++) {
540 case SSH_CHANNEL_X11_LISTENER:
541 case SSH_CHANNEL_PORT_LISTENER:
542 case SSH_CHANNEL_RPORT_LISTENER:
543 case SSH_CHANNEL_CLOSED:
544 case SSH_CHANNEL_AUTH_SOCKET:
545 case SSH_CHANNEL_ZOMBIE:
547 case SSH_CHANNEL_LARVAL:
548 case SSH_CHANNEL_OPENING:
549 case SSH_CHANNEL_CONNECTING:
550 case SSH_CHANNEL_DYNAMIC:
551 case SSH_CHANNEL_OPEN:
552 case SSH_CHANNEL_X11_OPEN:
553 case SSH_CHANNEL_INPUT_DRAINING:
554 case SSH_CHANNEL_OUTPUT_DRAINING:
555 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
556 c->self, c->remote_name,
557 c->type, c->remote_id,
558 c->istate, buffer_len(&c->input),
559 c->ostate, buffer_len(&c->output),
561 buffer_append(&buffer, buf, strlen(buf));
564 fatal("channel_open_message: bad channel type %d", c->type);
568 buffer_append(&buffer, "\0", 1);
569 cp = xstrdup(buffer_ptr(&buffer));
570 buffer_free(&buffer);
575 channel_send_open(int id)
577 Channel *c = channel_lookup(id);
579 log("channel_send_open: %d: bad id", id);
582 debug("send channel open %d", id);
583 packet_start(SSH2_MSG_CHANNEL_OPEN);
584 packet_put_cstring(c->ctype);
585 packet_put_int(c->self);
586 packet_put_int(c->local_window);
587 packet_put_int(c->local_maxpacket);
592 channel_request(int id, char *service, int wantconfirm)
594 channel_request_start(id, service, wantconfirm);
596 debug("channel request %d: %s", id, service) ;
599 channel_request_start(int id, char *service, int wantconfirm)
601 Channel *c = channel_lookup(id);
603 log("channel_request: %d: bad id", id);
606 packet_start(SSH2_MSG_CHANNEL_REQUEST);
607 packet_put_int(c->remote_id);
608 packet_put_cstring(service);
609 packet_put_char(wantconfirm);
612 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
614 Channel *c = channel_lookup(id);
616 log("channel_register_callback: %d: bad id", id);
624 channel_register_cleanup(int id, channel_callback_fn *fn)
626 Channel *c = channel_lookup(id);
628 log("channel_register_cleanup: %d: bad id", id);
634 channel_cancel_cleanup(int id)
636 Channel *c = channel_lookup(id);
638 log("channel_cancel_cleanup: %d: bad id", id);
641 c->detach_user = NULL;
644 channel_register_filter(int id, channel_filter_fn *fn)
646 Channel *c = channel_lookup(id);
648 log("channel_register_filter: %d: bad id", id);
651 c->input_filter = fn;
655 channel_set_fds(int id, int rfd, int wfd, int efd,
656 int extusage, int nonblock)
658 Channel *c = channel_lookup(id);
659 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
660 fatal("channel_activate for non-larval channel %d.", id);
661 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
662 c->type = SSH_CHANNEL_OPEN;
663 /* XXX window size? */
664 c->local_window = c->local_window_max = c->local_maxpacket * 2;
665 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
666 packet_put_int(c->remote_id);
667 packet_put_int(c->local_window);
672 * 'channel_pre*' are called just before select() to add any bits relevant to
673 * channels in the select bitmasks.
676 * 'channel_post*': perform any appropriate operations for channels which
677 * have events pending.
679 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
680 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
681 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
684 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
686 FD_SET(c->sock, readset);
690 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
692 debug3("channel %d: waiting for connection", c->self);
693 FD_SET(c->sock, writeset);
697 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
699 if (buffer_len(&c->input) < packet_get_maxsize())
700 FD_SET(c->sock, readset);
701 if (buffer_len(&c->output) > 0)
702 FD_SET(c->sock, writeset);
706 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
708 /* test whether sockets are 'alive' for read/write */
709 if (c->istate == CHAN_INPUT_OPEN)
710 if (buffer_len(&c->input) < packet_get_maxsize())
711 FD_SET(c->sock, readset);
712 if (c->ostate == CHAN_OUTPUT_OPEN ||
713 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
714 if (buffer_len(&c->output) > 0) {
715 FD_SET(c->sock, writeset);
716 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
723 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
725 if (c->istate == CHAN_INPUT_OPEN &&
726 c->remote_window > 0 &&
727 buffer_len(&c->input) < c->remote_window)
728 FD_SET(c->rfd, readset);
729 if (c->ostate == CHAN_OUTPUT_OPEN ||
730 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
731 if (buffer_len(&c->output) > 0) {
732 FD_SET(c->wfd, writeset);
733 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
737 /** XXX check close conditions, too */
739 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
740 buffer_len(&c->extended) > 0)
741 FD_SET(c->efd, writeset);
742 else if (c->extended_usage == CHAN_EXTENDED_READ &&
743 buffer_len(&c->extended) < c->remote_window)
744 FD_SET(c->efd, readset);
749 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
751 if (buffer_len(&c->input) == 0) {
752 packet_start(SSH_MSG_CHANNEL_CLOSE);
753 packet_put_int(c->remote_id);
755 c->type = SSH_CHANNEL_CLOSED;
756 debug("channel %d: closing after input drain.", c->self);
761 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
763 if (buffer_len(&c->output) == 0)
766 FD_SET(c->sock, writeset);
770 * This is a special state for X11 authentication spoofing. An opened X11
771 * connection (when authentication spoofing is being done) remains in this
772 * state until the first packet has been completely read. The authentication
773 * data in that packet is then substituted by the real data if it matches the
774 * fake data, and the channel is put into normal mode.
775 * XXX All this happens at the client side.
776 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
779 x11_open_helper(Buffer *b)
782 u_int proto_len, data_len;
784 /* Check if the fixed size part of the packet is in buffer. */
785 if (buffer_len(b) < 12)
788 /* Parse the lengths of variable-length fields. */
789 ucp = (u_char *) buffer_ptr(b);
790 if (ucp[0] == 0x42) { /* Byte order MSB first. */
791 proto_len = 256 * ucp[6] + ucp[7];
792 data_len = 256 * ucp[8] + ucp[9];
793 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
794 proto_len = ucp[6] + 256 * ucp[7];
795 data_len = ucp[8] + 256 * ucp[9];
797 debug("Initial X11 packet contains bad byte order byte: 0x%x",
802 /* Check if the whole packet is in buffer. */
804 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
807 /* Check if authentication protocol matches. */
808 if (proto_len != strlen(x11_saved_proto) ||
809 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
810 debug("X11 connection uses different authentication protocol.");
813 /* Check if authentication data matches our fake data. */
814 if (data_len != x11_fake_data_len ||
815 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
816 x11_fake_data, x11_fake_data_len) != 0) {
817 debug("X11 auth data does not match fake data.");
820 /* Check fake data length */
821 if (x11_fake_data_len != x11_saved_data_len) {
822 error("X11 fake_data_len %d != saved_data_len %d",
823 x11_fake_data_len, x11_saved_data_len);
827 * Received authentication protocol and data match
828 * our fake data. Substitute the fake data with real
831 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
832 x11_saved_data, x11_saved_data_len);
837 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
839 int ret = x11_open_helper(&c->output);
841 /* Start normal processing for the channel. */
842 c->type = SSH_CHANNEL_OPEN;
843 channel_pre_open_13(c, readset, writeset);
844 } else if (ret == -1) {
846 * We have received an X11 connection that has bad
847 * authentication information.
849 log("X11 connection rejected because of wrong authentication.");
850 buffer_clear(&c->input);
851 buffer_clear(&c->output);
852 channel_close_fd(&c->sock);
854 c->type = SSH_CHANNEL_CLOSED;
855 packet_start(SSH_MSG_CHANNEL_CLOSE);
856 packet_put_int(c->remote_id);
862 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
864 int ret = x11_open_helper(&c->output);
866 /* c->force_drain = 1; */
869 c->type = SSH_CHANNEL_OPEN;
871 channel_pre_open_20(c, readset, writeset);
873 channel_pre_open_15(c, readset, writeset);
874 } else if (ret == -1) {
875 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
876 chan_read_failed(c); /** force close? */
877 chan_write_failed(c);
878 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
882 /* try to decode a socks4 header */
884 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
887 int len, have, i, found;
893 struct in_addr dest_addr;
896 debug2("channel %d: decode socks4", c->self);
898 have = buffer_len(&c->input);
899 len = sizeof(s4_req);
902 p = buffer_ptr(&c->input);
903 for (found = 0, i = len; i < have; i++) {
909 /* the peer is probably sending garbage */
910 debug("channel %d: decode socks4: too long",
917 buffer_get(&c->input, (char *)&s4_req.version, 1);
918 buffer_get(&c->input, (char *)&s4_req.command, 1);
919 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
920 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
921 have = buffer_len(&c->input);
922 p = buffer_ptr(&c->input);
924 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
926 fatal("channel %d: decode socks4: len %d > have %d",
928 strlcpy(username, p, sizeof(username));
929 buffer_consume(&c->input, len);
930 buffer_consume(&c->input, 1); /* trailing '\0' */
932 host = inet_ntoa(s4_req.dest_addr);
933 strlcpy(c->path, host, sizeof(c->path));
934 c->host_port = ntohs(s4_req.dest_port);
936 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
937 c->self, host, c->host_port, s4_req.command);
939 if (s4_req.command != 1) {
940 debug("channel %d: cannot handle: socks4 cn %d",
941 c->self, s4_req.command);
944 s4_rsp.version = 0; /* vn: 0 for reply */
945 s4_rsp.command = 90; /* cd: req granted */
946 s4_rsp.dest_port = 0; /* ignored */
947 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
948 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
952 /* dynamic port forwarding */
954 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
959 have = buffer_len(&c->input);
961 debug2("channel %d: pre_dynamic: have %d", c->self, have);
962 /* buffer_dump(&c->input); */
963 /* check if the fixed size part of the packet is in buffer. */
966 FD_SET(c->sock, readset);
969 /* try to guess the protocol */
970 p = buffer_ptr(&c->input);
973 ret = channel_decode_socks4(c, readset, writeset);
981 } else if (ret == 0) {
982 debug2("channel %d: pre_dynamic: need more", c->self);
984 FD_SET(c->sock, readset);
986 /* switch to the next state */
987 c->type = SSH_CHANNEL_OPENING;
988 port_open_helper(c, "direct-tcpip");
992 /* This is our fake X11 server socket. */
994 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
997 struct sockaddr addr;
1000 char buf[16384], *remote_ipaddr;
1003 if (FD_ISSET(c->sock, readset)) {
1004 debug("X11 connection requested.");
1005 addrlen = sizeof(addr);
1006 newsock = accept(c->sock, &addr, &addrlen);
1007 if (c->single_connection) {
1008 debug("single_connection: closing X11 listener.");
1009 channel_close_fd(&c->sock);
1013 error("accept: %.100s", strerror(errno));
1016 if (setsockopt(newsock, IPPROTO_TCP, TCP_NODELAY, &on,
1018 error("setsockopt TCP_NODELAY: %.100s",
1020 remote_ipaddr = get_peer_ipaddr(newsock);
1021 remote_port = get_peer_port(newsock);
1022 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1023 remote_ipaddr, remote_port);
1025 nc = channel_new("accepted x11 socket",
1026 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1027 c->local_window_max, c->local_maxpacket,
1028 0, xstrdup(buf), 1);
1031 xfree(remote_ipaddr);
1035 packet_start(SSH2_MSG_CHANNEL_OPEN);
1036 packet_put_cstring("x11");
1037 packet_put_int(nc->self);
1038 packet_put_int(nc->local_window_max);
1039 packet_put_int(nc->local_maxpacket);
1040 /* originator ipaddr and port */
1041 packet_put_cstring(remote_ipaddr);
1042 if (datafellows & SSH_BUG_X11FWD) {
1043 debug("ssh2 x11 bug compat mode");
1045 packet_put_int(remote_port);
1049 packet_start(SSH_SMSG_X11_OPEN);
1050 packet_put_int(nc->self);
1051 if (packet_get_protocol_flags() &
1052 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1053 packet_put_cstring(buf);
1056 xfree(remote_ipaddr);
1061 port_open_helper(Channel *c, char *rtype)
1065 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1066 u_short remote_port = get_peer_port(c->sock);
1068 direct = (strcmp(rtype, "direct-tcpip") == 0);
1070 snprintf(buf, sizeof buf,
1071 "%s: listening port %d for %.100s port %d, "
1072 "connect from %.200s port %d",
1073 rtype, c->listening_port, c->path, c->host_port,
1074 remote_ipaddr, remote_port);
1076 xfree(c->remote_name);
1077 c->remote_name = xstrdup(buf);
1080 packet_start(SSH2_MSG_CHANNEL_OPEN);
1081 packet_put_cstring(rtype);
1082 packet_put_int(c->self);
1083 packet_put_int(c->local_window_max);
1084 packet_put_int(c->local_maxpacket);
1086 /* target host, port */
1087 packet_put_cstring(c->path);
1088 packet_put_int(c->host_port);
1090 /* listen address, port */
1091 packet_put_cstring(c->path);
1092 packet_put_int(c->listening_port);
1094 /* originator host and port */
1095 packet_put_cstring(remote_ipaddr);
1096 packet_put_int(remote_port);
1099 packet_start(SSH_MSG_PORT_OPEN);
1100 packet_put_int(c->self);
1101 packet_put_cstring(c->path);
1102 packet_put_int(c->host_port);
1103 if (packet_get_protocol_flags() &
1104 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1105 packet_put_cstring(c->remote_name);
1108 xfree(remote_ipaddr);
1112 * This socket is listening for connections to a forwarded TCP/IP port.
1115 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1118 struct sockaddr addr;
1119 int newsock, nextstate;
1123 if (FD_ISSET(c->sock, readset)) {
1124 debug("Connection to port %d forwarding "
1125 "to %.100s port %d requested.",
1126 c->listening_port, c->path, c->host_port);
1128 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1129 nextstate = SSH_CHANNEL_OPENING;
1130 rtype = "forwarded-tcpip";
1132 if (c->host_port == 0) {
1133 nextstate = SSH_CHANNEL_DYNAMIC;
1134 rtype = "dynamic-tcpip";
1136 nextstate = SSH_CHANNEL_OPENING;
1137 rtype = "direct-tcpip";
1141 addrlen = sizeof(addr);
1142 newsock = accept(c->sock, &addr, &addrlen);
1144 error("accept: %.100s", strerror(errno));
1147 nc = channel_new(rtype,
1148 nextstate, newsock, newsock, -1,
1149 c->local_window_max, c->local_maxpacket,
1150 0, xstrdup(rtype), 1);
1152 error("channel_post_port_listener: no new channel:");
1156 nc->listening_port = c->listening_port;
1157 nc->host_port = c->host_port;
1158 strlcpy(nc->path, c->path, sizeof(nc->path));
1160 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1162 * do not call the channel_post handler until
1163 * this flag has been reset by a pre-handler.
1164 * otherwise the FD_ISSET calls might overflow
1168 port_open_helper(nc, rtype);
1174 * This is the authentication agent socket listening for connections from
1178 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1183 struct sockaddr addr;
1186 if (FD_ISSET(c->sock, readset)) {
1187 addrlen = sizeof(addr);
1188 newsock = accept(c->sock, &addr, &addrlen);
1190 error("accept from auth socket: %.100s", strerror(errno));
1193 name = xstrdup("accepted auth socket");
1194 nc = channel_new("accepted auth socket",
1195 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1196 c->local_window_max, c->local_maxpacket,
1199 error("channel_post_auth_listener: channel_new failed");
1204 packet_start(SSH2_MSG_CHANNEL_OPEN);
1205 packet_put_cstring("auth-agent@openssh.com");
1206 packet_put_int(nc->self);
1207 packet_put_int(c->local_window_max);
1208 packet_put_int(c->local_maxpacket);
1210 packet_start(SSH_SMSG_AGENT_OPEN);
1211 packet_put_int(nc->self);
1218 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1221 socklen_t sz = sizeof(err);
1223 if (FD_ISSET(c->sock, writeset)) {
1224 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1227 error("getsockopt SO_ERROR failed");
1230 debug("channel %d: connected", c->self);
1231 c->type = SSH_CHANNEL_OPEN;
1233 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1234 packet_put_int(c->remote_id);
1235 packet_put_int(c->self);
1236 packet_put_int(c->local_window);
1237 packet_put_int(c->local_maxpacket);
1239 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1240 packet_put_int(c->remote_id);
1241 packet_put_int(c->self);
1244 debug("channel %d: not connected: %s",
1245 c->self, strerror(err));
1247 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1248 packet_put_int(c->remote_id);
1249 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1250 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1251 packet_put_cstring(strerror(err));
1252 packet_put_cstring("");
1255 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1256 packet_put_int(c->remote_id);
1265 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1271 FD_ISSET(c->rfd, readset)) {
1272 len = read(c->rfd, buf, sizeof(buf));
1273 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1276 debug("channel %d: read<=0 rfd %d len %d",
1277 c->self, c->rfd, len);
1278 if (c->type != SSH_CHANNEL_OPEN) {
1279 debug("channel %d: not open", c->self);
1282 } else if (compat13) {
1283 buffer_consume(&c->output, buffer_len(&c->output));
1284 c->type = SSH_CHANNEL_INPUT_DRAINING;
1285 debug("channel %d: input draining.", c->self);
1287 chan_read_failed(c);
1291 if (c->input_filter != NULL) {
1292 if (c->input_filter(c, buf, len) == -1) {
1293 debug("channel %d: filter stops", c->self);
1294 chan_read_failed(c);
1297 buffer_append(&c->input, buf, len);
1303 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1310 /* Send buffered output data to the socket. */
1312 FD_ISSET(c->wfd, writeset) &&
1313 buffer_len(&c->output) > 0) {
1314 data = buffer_ptr(&c->output);
1315 dlen = buffer_len(&c->output);
1316 len = write(c->wfd, data, dlen);
1317 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1320 if (c->type != SSH_CHANNEL_OPEN) {
1321 debug("channel %d: not open", c->self);
1324 } else if (compat13) {
1325 buffer_consume(&c->output, buffer_len(&c->output));
1326 debug("channel %d: input draining.", c->self);
1327 c->type = SSH_CHANNEL_INPUT_DRAINING;
1329 chan_write_failed(c);
1333 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1334 if (tcgetattr(c->wfd, &tio) == 0 &&
1335 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1337 * Simulate echo to reduce the impact of
1338 * traffic analysis. We need to match the
1339 * size of a SSH2_MSG_CHANNEL_DATA message
1340 * (4 byte channel id + data)
1342 packet_send_ignore(4 + len);
1346 buffer_consume(&c->output, len);
1347 if (compat20 && len > 0) {
1348 c->local_consumed += len;
1354 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1359 /** XXX handle drain efd, too */
1361 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1362 FD_ISSET(c->efd, writeset) &&
1363 buffer_len(&c->extended) > 0) {
1364 len = write(c->efd, buffer_ptr(&c->extended),
1365 buffer_len(&c->extended));
1366 debug2("channel %d: written %d to efd %d",
1367 c->self, len, c->efd);
1368 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1371 debug2("channel %d: closing write-efd %d",
1373 channel_close_fd(&c->efd);
1375 buffer_consume(&c->extended, len);
1376 c->local_consumed += len;
1378 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1379 FD_ISSET(c->efd, readset)) {
1380 len = read(c->efd, buf, sizeof(buf));
1381 debug2("channel %d: read %d from efd %d",
1382 c->self, len, c->efd);
1383 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1386 debug2("channel %d: closing read-efd %d",
1388 channel_close_fd(&c->efd);
1390 buffer_append(&c->extended, buf, len);
1397 channel_check_window(Channel *c)
1399 if (c->type == SSH_CHANNEL_OPEN &&
1400 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1401 c->local_window < c->local_window_max/2 &&
1402 c->local_consumed > 0) {
1403 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1404 packet_put_int(c->remote_id);
1405 packet_put_int(c->local_consumed);
1407 debug2("channel %d: window %d sent adjust %d",
1408 c->self, c->local_window,
1410 c->local_window += c->local_consumed;
1411 c->local_consumed = 0;
1417 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1421 channel_handle_rfd(c, readset, writeset);
1422 channel_handle_wfd(c, readset, writeset);
1426 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1430 channel_handle_rfd(c, readset, writeset);
1431 channel_handle_wfd(c, readset, writeset);
1432 channel_handle_efd(c, readset, writeset);
1434 channel_check_window(c);
1438 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1441 /* Send buffered output data to the socket. */
1442 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1443 len = write(c->sock, buffer_ptr(&c->output),
1444 buffer_len(&c->output));
1446 buffer_consume(&c->output, buffer_len(&c->output));
1448 buffer_consume(&c->output, len);
1453 channel_handler_init_20(void)
1455 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1456 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1457 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1458 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1459 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1460 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1461 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1462 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1464 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1465 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1466 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1467 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1468 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1469 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1470 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1474 channel_handler_init_13(void)
1476 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1477 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1478 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1479 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1480 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1481 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1482 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1483 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1484 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1486 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1487 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1488 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1489 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1490 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1491 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1492 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1496 channel_handler_init_15(void)
1498 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1499 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1500 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1501 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1502 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1503 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1504 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1506 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1507 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1508 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1509 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1510 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1511 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1515 channel_handler_init(void)
1518 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1519 channel_pre[i] = NULL;
1520 channel_post[i] = NULL;
1523 channel_handler_init_20();
1525 channel_handler_init_13();
1527 channel_handler_init_15();
1530 /* gc dead channels */
1532 channel_garbage_collect(Channel *c)
1536 if (c->detach_user != NULL) {
1537 if (!chan_is_dead(c, 0))
1539 debug("channel %d: gc: notify user", c->self);
1540 c->detach_user(c->self, NULL);
1541 /* if we still have a callback */
1542 if (c->detach_user != NULL)
1544 debug("channel %d: gc: user detached", c->self);
1546 if (!chan_is_dead(c, 1))
1548 debug("channel %d: garbage collecting", c->self);
1553 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1555 static int did_init = 0;
1560 channel_handler_init();
1563 for (i = 0; i < channels_alloc; i++) {
1567 if (ftab[c->type] != NULL)
1568 (*ftab[c->type])(c, readset, writeset);
1569 channel_garbage_collect(c);
1574 * Allocate/update select bitmasks and add any bits relevant to channels in
1578 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1579 int *nallocp, int rekeying)
1584 n = MAX(*maxfdp, channel_max_fd);
1586 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1587 /* perhaps check sz < nalloc/2 and shrink? */
1588 if (*readsetp == NULL || sz > *nallocp) {
1589 *readsetp = xrealloc(*readsetp, sz);
1590 *writesetp = xrealloc(*writesetp, sz);
1594 memset(*readsetp, 0, sz);
1595 memset(*writesetp, 0, sz);
1598 channel_handler(channel_pre, *readsetp, *writesetp);
1602 * After select, perform any appropriate operations for channels which have
1606 channel_after_select(fd_set * readset, fd_set * writeset)
1608 channel_handler(channel_post, readset, writeset);
1612 /* If there is data to send to the connection, enqueue some of it now. */
1615 channel_output_poll(void)
1620 for (i = 0; i < channels_alloc; i++) {
1626 * We are only interested in channels that can have buffered
1630 if (c->type != SSH_CHANNEL_OPEN &&
1631 c->type != SSH_CHANNEL_INPUT_DRAINING)
1634 if (c->type != SSH_CHANNEL_OPEN)
1638 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1639 /* XXX is this true? */
1640 debug3("channel %d: will not send data after close", c->self);
1644 /* Get the amount of buffered data for this channel. */
1645 if ((c->istate == CHAN_INPUT_OPEN ||
1646 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1647 (len = buffer_len(&c->input)) > 0) {
1649 * Send some data for the other side over the secure
1653 if (len > c->remote_window)
1654 len = c->remote_window;
1655 if (len > c->remote_maxpacket)
1656 len = c->remote_maxpacket;
1658 if (packet_is_interactive()) {
1662 /* Keep the packets at reasonable size. */
1663 if (len > packet_get_maxsize()/2)
1664 len = packet_get_maxsize()/2;
1668 packet_start(compat20 ?
1669 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1670 packet_put_int(c->remote_id);
1671 packet_put_string(buffer_ptr(&c->input), len);
1673 buffer_consume(&c->input, len);
1674 c->remote_window -= len;
1676 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1678 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1680 * input-buffer is empty and read-socket shutdown:
1681 * tell peer, that we will not send more data: send IEOF
1685 /* Send extended data, i.e. stderr */
1687 c->remote_window > 0 &&
1688 (len = buffer_len(&c->extended)) > 0 &&
1689 c->extended_usage == CHAN_EXTENDED_READ) {
1690 debug2("channel %d: rwin %d elen %d euse %d",
1691 c->self, c->remote_window, buffer_len(&c->extended),
1693 if (len > c->remote_window)
1694 len = c->remote_window;
1695 if (len > c->remote_maxpacket)
1696 len = c->remote_maxpacket;
1697 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1698 packet_put_int(c->remote_id);
1699 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1700 packet_put_string(buffer_ptr(&c->extended), len);
1702 buffer_consume(&c->extended, len);
1703 c->remote_window -= len;
1704 debug2("channel %d: sent ext data %d", c->self, len);
1710 /* -- protocol input */
1713 channel_input_data(int type, int plen, u_int32_t seq, void *ctxt)
1720 /* Get the channel number and verify it. */
1721 id = packet_get_int();
1722 c = channel_lookup(id);
1724 packet_disconnect("Received data for nonexistent channel %d.", id);
1726 /* Ignore any data for non-open channels (might happen on close) */
1727 if (c->type != SSH_CHANNEL_OPEN &&
1728 c->type != SSH_CHANNEL_X11_OPEN)
1731 /* same for protocol 1.5 if output end is no longer open */
1732 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1736 data = packet_get_string(&data_len);
1739 if (data_len > c->local_maxpacket) {
1740 log("channel %d: rcvd big packet %d, maxpack %d",
1741 c->self, data_len, c->local_maxpacket);
1743 if (data_len > c->local_window) {
1744 log("channel %d: rcvd too much data %d, win %d",
1745 c->self, data_len, c->local_window);
1749 c->local_window -= data_len;
1752 buffer_append(&c->output, data, data_len);
1757 channel_input_extended_data(int type, int plen, u_int32_t seq, void *ctxt)
1765 /* Get the channel number and verify it. */
1766 id = packet_get_int();
1767 c = channel_lookup(id);
1770 packet_disconnect("Received extended_data for bad channel %d.", id);
1771 if (c->type != SSH_CHANNEL_OPEN) {
1772 log("channel %d: ext data for non open", id);
1775 tcode = packet_get_int();
1777 c->extended_usage != CHAN_EXTENDED_WRITE ||
1778 tcode != SSH2_EXTENDED_DATA_STDERR) {
1779 log("channel %d: bad ext data", c->self);
1782 data = packet_get_string(&data_len);
1784 if (data_len > c->local_window) {
1785 log("channel %d: rcvd too much extended_data %d, win %d",
1786 c->self, data_len, c->local_window);
1790 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1791 c->local_window -= data_len;
1792 buffer_append(&c->extended, data, data_len);
1797 channel_input_ieof(int type, int plen, u_int32_t seq, void *ctxt)
1802 id = packet_get_int();
1804 c = channel_lookup(id);
1806 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1809 /* XXX force input close */
1810 if (c->force_drain) {
1811 debug("channel %d: FORCE input drain", c->self);
1812 c->istate = CHAN_INPUT_WAIT_DRAIN;
1818 channel_input_close(int type, int plen, u_int32_t seq, void *ctxt)
1823 id = packet_get_int();
1825 c = channel_lookup(id);
1827 packet_disconnect("Received close for nonexistent channel %d.", id);
1830 * Send a confirmation that we have closed the channel and no more
1831 * data is coming for it.
1833 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1834 packet_put_int(c->remote_id);
1838 * If the channel is in closed state, we have sent a close request,
1839 * and the other side will eventually respond with a confirmation.
1840 * Thus, we cannot free the channel here, because then there would be
1841 * no-one to receive the confirmation. The channel gets freed when
1842 * the confirmation arrives.
1844 if (c->type != SSH_CHANNEL_CLOSED) {
1846 * Not a closed channel - mark it as draining, which will
1847 * cause it to be freed later.
1849 buffer_consume(&c->input, buffer_len(&c->input));
1850 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1854 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1856 channel_input_oclose(int type, int plen, u_int32_t seq, void *ctxt)
1858 int id = packet_get_int();
1859 Channel *c = channel_lookup(id);
1863 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1864 chan_rcvd_oclose(c);
1868 channel_input_close_confirmation(int type, int plen, u_int32_t seq, void *ctxt)
1870 int id = packet_get_int();
1871 Channel *c = channel_lookup(id);
1875 packet_disconnect("Received close confirmation for "
1876 "out-of-range channel %d.", id);
1877 if (c->type != SSH_CHANNEL_CLOSED)
1878 packet_disconnect("Received close confirmation for "
1879 "non-closed channel %d (type %d).", id, c->type);
1884 channel_input_open_confirmation(int type, int plen, u_int32_t seq, void *ctxt)
1889 id = packet_get_int();
1890 c = channel_lookup(id);
1892 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1893 packet_disconnect("Received open confirmation for "
1894 "non-opening channel %d.", id);
1895 remote_id = packet_get_int();
1896 /* Record the remote channel number and mark that the channel is now open. */
1897 c->remote_id = remote_id;
1898 c->type = SSH_CHANNEL_OPEN;
1901 c->remote_window = packet_get_int();
1902 c->remote_maxpacket = packet_get_int();
1903 if (c->cb_fn != NULL && c->cb_event == type) {
1904 debug2("callback start");
1905 c->cb_fn(c->self, c->cb_arg);
1906 debug2("callback done");
1908 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1909 c->remote_window, c->remote_maxpacket);
1915 reason2txt(int reason)
1918 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1919 return "administratively prohibited";
1920 case SSH2_OPEN_CONNECT_FAILED:
1921 return "connect failed";
1922 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1923 return "unknown channel type";
1924 case SSH2_OPEN_RESOURCE_SHORTAGE:
1925 return "resource shortage";
1927 return "unknown reason";
1931 channel_input_open_failure(int type, int plen, u_int32_t seq, void *ctxt)
1934 char *msg = NULL, *lang = NULL;
1937 id = packet_get_int();
1938 c = channel_lookup(id);
1940 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1941 packet_disconnect("Received open failure for "
1942 "non-opening channel %d.", id);
1944 reason = packet_get_int();
1945 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1946 msg = packet_get_string(NULL);
1947 lang = packet_get_string(NULL);
1949 log("channel %d: open failed: %s%s%s", id,
1950 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1957 /* Free the channel. This will also close the socket. */
1962 channel_input_channel_request(int type, int plen, u_int32_t seq, void *ctxt)
1967 id = packet_get_int();
1968 c = channel_lookup(id);
1971 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1972 packet_disconnect("Received request for "
1973 "non-open channel %d.", id);
1974 if (c->cb_fn != NULL && c->cb_event == type) {
1975 debug2("callback start");
1976 c->cb_fn(c->self, c->cb_arg);
1977 debug2("callback done");
1979 char *service = packet_get_string(NULL);
1980 debug("channel %d: rcvd request for %s", c->self, service);
1981 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1987 channel_input_window_adjust(int type, int plen, u_int32_t seq, void *ctxt)
1995 /* Get the channel number and verify it. */
1996 id = packet_get_int();
1997 c = channel_lookup(id);
1999 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2000 log("Received window adjust for "
2001 "non-open channel %d.", id);
2004 adjust = packet_get_int();
2006 debug2("channel %d: rcvd adjust %d", id, adjust);
2007 c->remote_window += adjust;
2011 channel_input_port_open(int type, int plen, u_int32_t seq, void *ctxt)
2015 char *host, *originator_string;
2016 int remote_id, sock = -1;
2018 remote_id = packet_get_int();
2019 host = packet_get_string(NULL);
2020 host_port = packet_get_int();
2022 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2023 originator_string = packet_get_string(NULL);
2025 originator_string = xstrdup("unknown (remote did not supply name)");
2028 sock = channel_connect_to(host, host_port);
2030 c = channel_new("connected socket",
2031 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2032 originator_string, 1);
2034 error("channel_input_port_open: channel_new failed");
2037 c->remote_id = remote_id;
2041 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2042 packet_put_int(remote_id);
2049 /* -- tcp forwarding */
2052 channel_set_af(int af)
2058 * Initiate forwarding of connections to local port "port" through the secure
2059 * channel to host:port from remote side.
2062 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2063 u_short port_to_connect, int gateway_ports)
2065 return channel_request_forwarding(
2067 host_to_connect, port_to_connect,
2068 gateway_ports, /*remote_fwd*/ 0);
2072 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2073 * (SSH_CHANNEL_RPORT_LISTENER).
2076 channel_request_forwarding(
2077 const char *listen_address, u_short listen_port,
2078 const char *host_to_connect, u_short port_to_connect,
2079 int gateway_ports, int remote_fwd)
2082 int success, sock, on = 1, type;
2083 struct addrinfo hints, *ai, *aitop;
2084 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2086 struct linger linger;
2091 host = listen_address;
2092 type = SSH_CHANNEL_RPORT_LISTENER;
2094 host = host_to_connect;
2095 type = SSH_CHANNEL_PORT_LISTENER;
2098 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2099 error("Forward host name too long.");
2103 /* XXX listen_address is currently ignored */
2105 * getaddrinfo returns a loopback address if the hostname is
2106 * set to NULL and hints.ai_flags is not AI_PASSIVE
2108 memset(&hints, 0, sizeof(hints));
2109 hints.ai_family = IPv4or6;
2110 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2111 hints.ai_socktype = SOCK_STREAM;
2112 snprintf(strport, sizeof strport, "%d", listen_port);
2113 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2114 packet_disconnect("getaddrinfo: fatal error");
2116 for (ai = aitop; ai; ai = ai->ai_next) {
2117 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2119 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2120 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2121 error("channel_request_forwarding: getnameinfo failed");
2124 /* Create a port to listen for the host. */
2125 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2127 /* this is no error since kernel may not support ipv6 */
2128 verbose("socket: %.100s", strerror(errno));
2132 * Set socket options. We would like the socket to disappear
2133 * as soon as it has been closed for whatever reason.
2135 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2137 linger.l_linger = 5;
2138 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2139 debug("Local forwarding listening on %s port %s.", ntop, strport);
2141 /* Bind the socket to the address. */
2142 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2143 /* address can be in use ipv6 address is already bound */
2145 error("bind: %.100s", strerror(errno));
2147 verbose("bind: %.100s", strerror(errno));
2152 /* Start listening for connections on the socket. */
2153 if (listen(sock, 5) < 0) {
2154 error("listen: %.100s", strerror(errno));
2158 /* Allocate a channel number for the socket. */
2159 c = channel_new("port listener", type, sock, sock, -1,
2160 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2161 0, xstrdup("port listener"), 1);
2163 error("channel_request_forwarding: channel_new failed");
2167 strlcpy(c->path, host, sizeof(c->path));
2168 c->host_port = port_to_connect;
2169 c->listening_port = listen_port;
2173 error("channel_request_forwarding: cannot listen to port: %d",
2175 freeaddrinfo(aitop);
2180 * Initiate forwarding of connections to port "port" on remote host through
2181 * the secure channel to host:port from local side.
2185 channel_request_remote_forwarding(u_short listen_port,
2186 const char *host_to_connect, u_short port_to_connect)
2188 int type, success = 0;
2190 /* Record locally that connection to this host/port is permitted. */
2191 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2192 fatal("channel_request_remote_forwarding: too many forwards");
2194 /* Send the forward request to the remote side. */
2196 const char *address_to_bind = "0.0.0.0";
2197 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2198 packet_put_cstring("tcpip-forward");
2199 packet_put_char(0); /* boolean: want reply */
2200 packet_put_cstring(address_to_bind);
2201 packet_put_int(listen_port);
2203 packet_write_wait();
2204 /* Assume that server accepts the request */
2207 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2208 packet_put_int(listen_port);
2209 packet_put_cstring(host_to_connect);
2210 packet_put_int(port_to_connect);
2212 packet_write_wait();
2214 /* Wait for response from the remote side. */
2215 type = packet_read();
2217 case SSH_SMSG_SUCCESS:
2220 case SSH_SMSG_FAILURE:
2221 log("Warning: Server denied remote port forwarding.");
2224 /* Unknown packet */
2225 packet_disconnect("Protocol error for port forward request:"
2226 "received packet type %d.", type);
2230 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2231 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2232 permitted_opens[num_permitted_opens].listen_port = listen_port;
2233 num_permitted_opens++;
2238 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2239 * listening for the port, and sends back a success reply (or disconnect
2240 * message if there was an error). This never returns if there was an error.
2244 channel_input_port_forward_request(int is_root, int gateway_ports)
2246 u_short port, host_port;
2249 /* Get arguments from the packet. */
2250 port = packet_get_int();
2251 hostname = packet_get_string(NULL);
2252 host_port = packet_get_int();
2256 * Check that an unprivileged user is not trying to forward a
2259 if (port < IPPORT_RESERVED && !is_root)
2260 packet_disconnect("Requested forwarding of port %d but user is not root.",
2263 /* Initiate forwarding */
2264 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2266 /* Free the argument string. */
2271 * Permits opening to any host/port if permitted_opens[] is empty. This is
2272 * usually called by the server, because the user could connect to any port
2273 * anyway, and the server has no way to know but to trust the client anyway.
2276 channel_permit_all_opens(void)
2278 if (num_permitted_opens == 0)
2279 all_opens_permitted = 1;
2283 channel_add_permitted_opens(char *host, int port)
2285 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2286 fatal("channel_request_remote_forwarding: too many forwards");
2287 debug("allow port forwarding to host %s port %d", host, port);
2289 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2290 permitted_opens[num_permitted_opens].port_to_connect = port;
2291 num_permitted_opens++;
2293 all_opens_permitted = 0;
2297 channel_clear_permitted_opens(void)
2301 for (i = 0; i < num_permitted_opens; i++)
2302 xfree(permitted_opens[i].host_to_connect);
2303 num_permitted_opens = 0;
2308 /* return socket to remote host, port */
2310 connect_to(const char *host, u_short port)
2312 struct addrinfo hints, *ai, *aitop;
2313 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2317 memset(&hints, 0, sizeof(hints));
2318 hints.ai_family = IPv4or6;
2319 hints.ai_socktype = SOCK_STREAM;
2320 snprintf(strport, sizeof strport, "%d", port);
2321 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2322 error("connect_to %.100s: unknown host (%s)", host,
2323 gai_strerror(gaierr));
2326 for (ai = aitop; ai; ai = ai->ai_next) {
2327 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2329 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2330 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2331 error("connect_to: getnameinfo failed");
2334 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2336 error("socket: %.100s", strerror(errno));
2339 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2340 fatal("connect_to: F_SETFL: %s", strerror(errno));
2341 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2342 errno != EINPROGRESS) {
2343 error("connect_to %.100s port %s: %.100s", ntop, strport,
2346 continue; /* fail -- try next */
2348 break; /* success */
2351 freeaddrinfo(aitop);
2353 error("connect_to %.100s port %d: failed.", host, port);
2361 channel_connect_by_listen_address(u_short listen_port)
2365 for (i = 0; i < num_permitted_opens; i++)
2366 if (permitted_opens[i].listen_port == listen_port)
2368 permitted_opens[i].host_to_connect,
2369 permitted_opens[i].port_to_connect);
2370 error("WARNING: Server requests forwarding for unknown listen_port %d",
2375 /* Check if connecting to that port is permitted and connect. */
2377 channel_connect_to(const char *host, u_short port)
2381 permit = all_opens_permitted;
2383 for (i = 0; i < num_permitted_opens; i++)
2384 if (permitted_opens[i].port_to_connect == port &&
2385 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2390 log("Received request to connect to host %.100s port %d, "
2391 "but the request was denied.", host, port);
2394 return connect_to(host, port);
2397 /* -- X11 forwarding */
2400 * Creates an internet domain socket for listening for X11 connections.
2401 * Returns a suitable display number for the DISPLAY variable, or -1 if
2405 x11_create_display_inet(int x11_display_offset, int gateway_ports,
2406 int single_connection)
2409 int display_number, sock;
2411 struct addrinfo hints, *ai, *aitop;
2412 char strport[NI_MAXSERV];
2413 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2415 for (display_number = x11_display_offset;
2416 display_number < MAX_DISPLAYS;
2418 port = 6000 + display_number;
2419 memset(&hints, 0, sizeof(hints));
2420 hints.ai_family = IPv4or6;
2421 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2422 hints.ai_socktype = SOCK_STREAM;
2423 snprintf(strport, sizeof strport, "%d", port);
2424 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2425 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2428 for (ai = aitop; ai; ai = ai->ai_next) {
2429 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2431 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2433 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2434 error("socket: %.100s", strerror(errno));
2437 debug("x11_create_display_inet: Socket family %d not supported",
2442 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2443 debug("bind port %d: %.100s", port, strerror(errno));
2449 for (n = 0; n < num_socks; n++) {
2455 socks[num_socks++] = sock;
2456 #ifndef DONT_TRY_OTHER_AF
2457 if (num_socks == NUM_SOCKS)
2463 freeaddrinfo(aitop);
2467 if (display_number >= MAX_DISPLAYS) {
2468 error("Failed to allocate internet-domain X11 display socket.");
2471 /* Start listening for connections on the socket. */
2472 for (n = 0; n < num_socks; n++) {
2474 if (listen(sock, 5) < 0) {
2475 error("listen: %.100s", strerror(errno));
2481 /* Allocate a channel for each socket. */
2482 for (n = 0; n < num_socks; n++) {
2484 nc = 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);
2489 nc->single_connection = single_connection;
2492 /* Return the display number for the DISPLAY environment variable. */
2493 return display_number;
2497 connect_local_xsocket(u_int dnr)
2500 struct sockaddr_un addr;
2502 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2504 error("socket: %.100s", strerror(errno));
2505 memset(&addr, 0, sizeof(addr));
2506 addr.sun_family = AF_UNIX;
2507 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2508 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2511 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2516 x11_connect_display(void)
2518 int display_number, sock = 0, on = 1;
2519 const char *display;
2520 char buf[1024], *cp;
2521 struct addrinfo hints, *ai, *aitop;
2522 char strport[NI_MAXSERV];
2525 /* Try to open a socket for the local X server. */
2526 display = getenv("DISPLAY");
2528 error("DISPLAY not set.");
2532 * Now we decode the value of the DISPLAY variable and make a
2533 * connection to the real X server.
2537 * Check if it is a unix domain socket. Unix domain displays are in
2538 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2540 if (strncmp(display, "unix:", 5) == 0 ||
2541 display[0] == ':') {
2542 /* Connect to the unix domain socket. */
2543 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2544 error("Could not parse display number from DISPLAY: %.100s",
2548 /* Create a socket. */
2549 sock = connect_local_xsocket(display_number);
2553 /* OK, we now have a connection to the display. */
2557 * Connect to an inet socket. The DISPLAY value is supposedly
2558 * hostname:d[.s], where hostname may also be numeric IP address.
2560 strlcpy(buf, display, sizeof(buf));
2561 cp = strchr(buf, ':');
2563 error("Could not find ':' in DISPLAY: %.100s", display);
2567 /* buf now contains the host name. But first we parse the display number. */
2568 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2569 error("Could not parse display number from DISPLAY: %.100s",
2574 /* Look up the host address */
2575 memset(&hints, 0, sizeof(hints));
2576 hints.ai_family = IPv4or6;
2577 hints.ai_socktype = SOCK_STREAM;
2578 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2579 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2580 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2583 for (ai = aitop; ai; ai = ai->ai_next) {
2584 /* Create a socket. */
2585 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2587 debug("socket: %.100s", strerror(errno));
2590 /* Connect it to the display. */
2591 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2592 debug("connect %.100s port %d: %.100s", buf,
2593 6000 + display_number, strerror(errno));
2600 freeaddrinfo(aitop);
2602 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2606 if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on) == -1)
2607 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
2612 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2613 * the remote channel number. We should do whatever we want, and respond
2614 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2618 x11_input_open(int type, int plen, u_int32_t seq, void *ctxt)
2621 int remote_id, sock = 0;
2624 debug("Received X11 open request.");
2626 remote_id = packet_get_int();
2628 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2629 remote_host = packet_get_string(NULL);
2631 remote_host = xstrdup("unknown (remote did not supply name)");
2635 /* Obtain a connection to the real X display. */
2636 sock = x11_connect_display();
2638 /* Allocate a channel for this connection. */
2639 c = channel_new("connected x11 socket",
2640 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2643 error("x11_input_open: channel_new failed");
2646 c->remote_id = remote_id;
2651 /* Send refusal to the remote host. */
2652 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2653 packet_put_int(remote_id);
2655 /* Send a confirmation to the remote host. */
2656 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2657 packet_put_int(remote_id);
2658 packet_put_int(c->self);
2663 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2665 deny_input_open(int type, int plen, u_int32_t seq, void *ctxt)
2667 int rchan = packet_get_int();
2669 case SSH_SMSG_AGENT_OPEN:
2670 error("Warning: ssh server tried agent forwarding.");
2672 case SSH_SMSG_X11_OPEN:
2673 error("Warning: ssh server tried X11 forwarding.");
2676 error("deny_input_open: type %d plen %d", type, plen);
2679 error("Warning: this is probably a break in attempt by a malicious server.");
2680 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2681 packet_put_int(rchan);
2686 * Requests forwarding of X11 connections, generates fake authentication
2687 * data, and enables authentication spoofing.
2688 * This should be called in the client only.
2691 x11_request_forwarding_with_spoofing(int client_session_id,
2692 const char *proto, const char *data)
2694 u_int data_len = (u_int) strlen(data) / 2;
2695 u_int i, value, len;
2701 cp = getenv("DISPLAY");
2703 cp = strchr(cp, ':');
2705 cp = strchr(cp, '.');
2707 screen_number = atoi(cp + 1);
2711 /* Save protocol name. */
2712 x11_saved_proto = xstrdup(proto);
2715 * Extract real authentication data and generate fake data of the
2718 x11_saved_data = xmalloc(data_len);
2719 x11_fake_data = xmalloc(data_len);
2720 for (i = 0; i < data_len; i++) {
2721 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2722 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2724 rand = arc4random();
2725 x11_saved_data[i] = value;
2726 x11_fake_data[i] = rand & 0xff;
2729 x11_saved_data_len = data_len;
2730 x11_fake_data_len = data_len;
2732 /* Convert the fake data into hex. */
2733 len = 2 * data_len + 1;
2734 new_data = xmalloc(len);
2735 for (i = 0; i < data_len; i++)
2736 snprintf(new_data + 2 * i, len - 2 * i,
2737 "%02x", (u_char) x11_fake_data[i]);
2739 /* Send the request packet. */
2741 channel_request_start(client_session_id, "x11-req", 0);
2742 packet_put_char(0); /* XXX bool single connection */
2744 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2746 packet_put_cstring(proto);
2747 packet_put_cstring(new_data);
2748 packet_put_int(screen_number);
2750 packet_write_wait();
2755 /* -- agent forwarding */
2757 /* Sends a message to the server to request authentication fd forwarding. */
2760 auth_request_forwarding(void)
2762 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2764 packet_write_wait();
2768 * Returns the name of the forwarded authentication socket. Returns NULL if
2769 * there is no forwarded authentication socket. The returned value points to
2774 auth_get_socket_name(void)
2776 return auth_sock_name;
2779 /* removes the agent forwarding socket */
2782 auth_sock_cleanup_proc(void *_pw)
2784 struct passwd *pw = _pw;
2786 if (auth_sock_name) {
2787 temporarily_use_uid(pw);
2788 unlink(auth_sock_name);
2789 rmdir(auth_sock_dir);
2790 auth_sock_name = NULL;
2796 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2797 * This starts forwarding authentication requests.
2801 auth_input_request_forwarding(struct passwd * pw)
2805 struct sockaddr_un sunaddr;
2807 if (auth_get_socket_name() != NULL) {
2808 error("authentication forwarding requested twice.");
2812 /* Temporarily drop privileged uid for mkdir/bind. */
2813 temporarily_use_uid(pw);
2815 /* Allocate a buffer for the socket name, and format the name. */
2816 auth_sock_name = xmalloc(MAXPATHLEN);
2817 auth_sock_dir = xmalloc(MAXPATHLEN);
2818 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2820 /* Create private directory for socket */
2821 if (mkdtemp(auth_sock_dir) == NULL) {
2822 packet_send_debug("Agent forwarding disabled: "
2823 "mkdtemp() failed: %.100s", strerror(errno));
2825 xfree(auth_sock_name);
2826 xfree(auth_sock_dir);
2827 auth_sock_name = NULL;
2828 auth_sock_dir = NULL;
2831 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2832 auth_sock_dir, (int) getpid());
2834 /* delete agent socket on fatal() */
2835 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2837 /* Create the socket. */
2838 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2840 packet_disconnect("socket: %.100s", strerror(errno));
2842 /* Bind it to the name. */
2843 memset(&sunaddr, 0, sizeof(sunaddr));
2844 sunaddr.sun_family = AF_UNIX;
2845 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
2847 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2848 packet_disconnect("bind: %.100s", strerror(errno));
2850 /* Restore the privileged uid. */
2853 /* Start listening on the socket. */
2854 if (listen(sock, 5) < 0)
2855 packet_disconnect("listen: %.100s", strerror(errno));
2857 /* Allocate a channel for the authentication agent socket. */
2858 nc = channel_new("auth socket",
2859 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2860 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2861 0, xstrdup("auth socket"), 1);
2863 error("auth_input_request_forwarding: channel_new failed");
2864 auth_sock_cleanup_proc(pw);
2865 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2869 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2873 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2876 auth_input_open_request(int type, int plen, u_int32_t seq, void *ctxt)
2879 int remote_id, sock;
2882 /* Read the remote channel number from the message. */
2883 remote_id = packet_get_int();
2887 * Get a connection to the local authentication agent (this may again
2890 sock = ssh_get_authentication_socket();
2893 * If we could not connect the agent, send an error message back to
2894 * the server. This should never happen unless the agent dies,
2895 * because authentication forwarding is only enabled if we have an
2899 name = xstrdup("authentication agent connection");
2900 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2901 -1, 0, 0, 0, name, 1);
2903 error("auth_input_open_request: channel_new failed");
2907 c->remote_id = remote_id;
2912 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2913 packet_put_int(remote_id);
2915 /* Send a confirmation to the remote host. */
2916 debug("Forwarding authentication connection.");
2917 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2918 packet_put_int(remote_id);
2919 packet_put_int(c->self);