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 1.132 2001/07/17 21:04:56 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);
270 channel_find_maxfd(void)
275 for (i = 0; i < channels_alloc; i++) {
278 max = MAX(max, c->rfd);
279 max = MAX(max, c->wfd);
280 max = MAX(max, c->efd);
287 channel_close_fd(int *fdp)
289 int ret = 0, fd = *fdp;
294 if (fd == channel_max_fd)
295 channel_max_fd = channel_find_maxfd();
300 /* Close all channel fd/socket. */
303 channel_close_fds(Channel *c)
305 debug3("channel_close_fds: channel %d: r %d w %d e %d",
306 c->self, c->rfd, c->wfd, c->efd);
308 channel_close_fd(&c->sock);
309 channel_close_fd(&c->rfd);
310 channel_close_fd(&c->wfd);
311 channel_close_fd(&c->efd);
314 /* Free the channel and close its fd/socket. */
317 channel_free(Channel *c)
322 for (n = 0, i = 0; i < channels_alloc; i++)
325 debug("channel_free: channel %d: %s, nchannels %d", c->self,
326 c->remote_name ? c->remote_name : "???", n);
328 s = channel_open_message();
329 debug3("channel_free: status: %s", s);
332 if (c->detach_user != NULL) {
333 debug("channel_free: channel %d: detaching channel user", c->self);
334 c->detach_user(c->self, NULL);
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 channel_detach_all(void)
366 for (i = 0; i < channels_alloc; i++) {
368 if (c != NULL && c->detach_user != NULL) {
369 debug("channel_detach_all: channel %d", c->self);
370 c->detach_user(c->self, NULL);
371 c->detach_user = NULL;
377 * Closes the sockets/fds of all channels. This is used to close extra file
378 * descriptors after a fork.
386 for (i = 0; i < channels_alloc; i++)
387 if (channels[i] != NULL)
388 channel_close_fds(channels[i]);
392 * Stop listening to channels.
396 channel_stop_listening(void)
401 for (i = 0; i < channels_alloc; i++) {
405 case SSH_CHANNEL_AUTH_SOCKET:
406 case SSH_CHANNEL_PORT_LISTENER:
407 case SSH_CHANNEL_RPORT_LISTENER:
408 case SSH_CHANNEL_X11_LISTENER:
409 channel_close_fd(&c->sock);
418 * Returns true if no channel has too much buffered data, and false if one or
419 * more channel is overfull.
423 channel_not_very_much_buffered_data()
428 for (i = 0; i < channels_alloc; i++) {
430 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
431 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
432 debug("channel %d: big input buffer %d",
433 c->self, buffer_len(&c->input));
436 if (buffer_len(&c->output) > packet_get_maxsize()) {
437 debug("channel %d: big output buffer %d",
438 c->self, buffer_len(&c->output));
446 /* Returns true if any channel is still open. */
454 for (i = 0; i < channels_alloc; i++) {
459 case SSH_CHANNEL_X11_LISTENER:
460 case SSH_CHANNEL_PORT_LISTENER:
461 case SSH_CHANNEL_RPORT_LISTENER:
462 case SSH_CHANNEL_CLOSED:
463 case SSH_CHANNEL_AUTH_SOCKET:
464 case SSH_CHANNEL_DYNAMIC:
465 case SSH_CHANNEL_CONNECTING:
466 case SSH_CHANNEL_ZOMBIE:
468 case SSH_CHANNEL_LARVAL:
470 fatal("cannot happen: SSH_CHANNEL_LARVAL");
472 case SSH_CHANNEL_OPENING:
473 case SSH_CHANNEL_OPEN:
474 case SSH_CHANNEL_X11_OPEN:
476 case SSH_CHANNEL_INPUT_DRAINING:
477 case SSH_CHANNEL_OUTPUT_DRAINING:
479 fatal("cannot happen: OUT_DRAIN");
482 fatal("channel_still_open: bad channel type %d", c->type);
489 /* Returns the id of an open channel suitable for keepaliving */
497 for (i = 0; i < channels_alloc; i++) {
502 case SSH_CHANNEL_CLOSED:
503 case SSH_CHANNEL_DYNAMIC:
504 case SSH_CHANNEL_X11_LISTENER:
505 case SSH_CHANNEL_PORT_LISTENER:
506 case SSH_CHANNEL_RPORT_LISTENER:
507 case SSH_CHANNEL_OPENING:
508 case SSH_CHANNEL_CONNECTING:
509 case SSH_CHANNEL_ZOMBIE:
511 case SSH_CHANNEL_LARVAL:
512 case SSH_CHANNEL_AUTH_SOCKET:
513 case SSH_CHANNEL_OPEN:
514 case SSH_CHANNEL_X11_OPEN:
516 case SSH_CHANNEL_INPUT_DRAINING:
517 case SSH_CHANNEL_OUTPUT_DRAINING:
519 fatal("cannot happen: OUT_DRAIN");
522 fatal("channel_find_open: bad channel type %d", c->type);
531 * Returns a message describing the currently open forwarded connections,
532 * suitable for sending to the client. The message contains crlf pairs for
537 channel_open_message()
544 buffer_init(&buffer);
545 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
546 buffer_append(&buffer, buf, strlen(buf));
547 for (i = 0; i < channels_alloc; i++) {
552 case SSH_CHANNEL_X11_LISTENER:
553 case SSH_CHANNEL_PORT_LISTENER:
554 case SSH_CHANNEL_RPORT_LISTENER:
555 case SSH_CHANNEL_CLOSED:
556 case SSH_CHANNEL_AUTH_SOCKET:
557 case SSH_CHANNEL_ZOMBIE:
559 case SSH_CHANNEL_LARVAL:
560 case SSH_CHANNEL_OPENING:
561 case SSH_CHANNEL_CONNECTING:
562 case SSH_CHANNEL_DYNAMIC:
563 case SSH_CHANNEL_OPEN:
564 case SSH_CHANNEL_X11_OPEN:
565 case SSH_CHANNEL_INPUT_DRAINING:
566 case SSH_CHANNEL_OUTPUT_DRAINING:
567 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
568 c->self, c->remote_name,
569 c->type, c->remote_id,
570 c->istate, buffer_len(&c->input),
571 c->ostate, buffer_len(&c->output),
573 buffer_append(&buffer, buf, strlen(buf));
576 fatal("channel_open_message: bad channel type %d", c->type);
580 buffer_append(&buffer, "\0", 1);
581 cp = xstrdup(buffer_ptr(&buffer));
582 buffer_free(&buffer);
587 channel_send_open(int id)
589 Channel *c = channel_lookup(id);
591 log("channel_send_open: %d: bad id", id);
594 debug("send channel open %d", id);
595 packet_start(SSH2_MSG_CHANNEL_OPEN);
596 packet_put_cstring(c->ctype);
597 packet_put_int(c->self);
598 packet_put_int(c->local_window);
599 packet_put_int(c->local_maxpacket);
604 channel_request(int id, char *service, int wantconfirm)
606 channel_request_start(id, service, wantconfirm);
608 debug("channel request %d: %s", id, service) ;
611 channel_request_start(int id, char *service, int wantconfirm)
613 Channel *c = channel_lookup(id);
615 log("channel_request: %d: bad id", id);
618 packet_start(SSH2_MSG_CHANNEL_REQUEST);
619 packet_put_int(c->remote_id);
620 packet_put_cstring(service);
621 packet_put_char(wantconfirm);
624 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
626 Channel *c = channel_lookup(id);
628 log("channel_register_callback: %d: bad id", id);
636 channel_register_cleanup(int id, channel_callback_fn *fn)
638 Channel *c = channel_lookup(id);
640 log("channel_register_cleanup: %d: bad id", id);
646 channel_cancel_cleanup(int id)
648 Channel *c = channel_lookup(id);
650 log("channel_cancel_cleanup: %d: bad id", id);
653 c->detach_user = NULL;
656 channel_register_filter(int id, channel_filter_fn *fn)
658 Channel *c = channel_lookup(id);
660 log("channel_register_filter: %d: bad id", id);
663 c->input_filter = fn;
667 channel_set_fds(int id, int rfd, int wfd, int efd,
668 int extusage, int nonblock)
670 Channel *c = channel_lookup(id);
671 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
672 fatal("channel_activate for non-larval channel %d.", id);
673 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
674 c->type = SSH_CHANNEL_OPEN;
675 /* XXX window size? */
676 c->local_window = c->local_window_max = c->local_maxpacket * 2;
677 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
678 packet_put_int(c->remote_id);
679 packet_put_int(c->local_window);
684 * 'channel_pre*' are called just before select() to add any bits relevant to
685 * channels in the select bitmasks.
688 * 'channel_post*': perform any appropriate operations for channels which
689 * have events pending.
691 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
692 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
693 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
696 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
698 FD_SET(c->sock, readset);
702 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
704 debug3("channel %d: waiting for connection", c->self);
705 FD_SET(c->sock, writeset);
709 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
711 if (buffer_len(&c->input) < packet_get_maxsize())
712 FD_SET(c->sock, readset);
713 if (buffer_len(&c->output) > 0)
714 FD_SET(c->sock, writeset);
718 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
720 /* test whether sockets are 'alive' for read/write */
721 if (c->istate == CHAN_INPUT_OPEN)
722 if (buffer_len(&c->input) < packet_get_maxsize())
723 FD_SET(c->sock, readset);
724 if (c->ostate == CHAN_OUTPUT_OPEN ||
725 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
726 if (buffer_len(&c->output) > 0) {
727 FD_SET(c->sock, writeset);
728 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
735 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
737 if (c->istate == CHAN_INPUT_OPEN &&
738 c->remote_window > 0 &&
739 buffer_len(&c->input) < c->remote_window)
740 FD_SET(c->rfd, readset);
741 if (c->ostate == CHAN_OUTPUT_OPEN ||
742 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
743 if (buffer_len(&c->output) > 0) {
744 FD_SET(c->wfd, writeset);
745 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
749 /** XXX check close conditions, too */
751 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
752 buffer_len(&c->extended) > 0)
753 FD_SET(c->efd, writeset);
754 else if (c->extended_usage == CHAN_EXTENDED_READ &&
755 buffer_len(&c->extended) < c->remote_window)
756 FD_SET(c->efd, readset);
761 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
763 if (buffer_len(&c->input) == 0) {
764 packet_start(SSH_MSG_CHANNEL_CLOSE);
765 packet_put_int(c->remote_id);
767 c->type = SSH_CHANNEL_CLOSED;
768 debug("channel %d: closing after input drain.", c->self);
773 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
775 if (buffer_len(&c->output) == 0)
778 FD_SET(c->sock, writeset);
782 * This is a special state for X11 authentication spoofing. An opened X11
783 * connection (when authentication spoofing is being done) remains in this
784 * state until the first packet has been completely read. The authentication
785 * data in that packet is then substituted by the real data if it matches the
786 * fake data, and the channel is put into normal mode.
787 * XXX All this happens at the client side.
788 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
791 x11_open_helper(Buffer *b)
794 u_int proto_len, data_len;
796 /* Check if the fixed size part of the packet is in buffer. */
797 if (buffer_len(b) < 12)
800 /* Parse the lengths of variable-length fields. */
801 ucp = (u_char *) buffer_ptr(b);
802 if (ucp[0] == 0x42) { /* Byte order MSB first. */
803 proto_len = 256 * ucp[6] + ucp[7];
804 data_len = 256 * ucp[8] + ucp[9];
805 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
806 proto_len = ucp[6] + 256 * ucp[7];
807 data_len = ucp[8] + 256 * ucp[9];
809 debug("Initial X11 packet contains bad byte order byte: 0x%x",
814 /* Check if the whole packet is in buffer. */
816 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
819 /* Check if authentication protocol matches. */
820 if (proto_len != strlen(x11_saved_proto) ||
821 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
822 debug("X11 connection uses different authentication protocol.");
825 /* Check if authentication data matches our fake data. */
826 if (data_len != x11_fake_data_len ||
827 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
828 x11_fake_data, x11_fake_data_len) != 0) {
829 debug("X11 auth data does not match fake data.");
832 /* Check fake data length */
833 if (x11_fake_data_len != x11_saved_data_len) {
834 error("X11 fake_data_len %d != saved_data_len %d",
835 x11_fake_data_len, x11_saved_data_len);
839 * Received authentication protocol and data match
840 * our fake data. Substitute the fake data with real
843 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
844 x11_saved_data, x11_saved_data_len);
849 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
851 int ret = x11_open_helper(&c->output);
853 /* Start normal processing for the channel. */
854 c->type = SSH_CHANNEL_OPEN;
855 channel_pre_open_13(c, readset, writeset);
856 } else if (ret == -1) {
858 * We have received an X11 connection that has bad
859 * authentication information.
861 log("X11 connection rejected because of wrong authentication.");
862 buffer_clear(&c->input);
863 buffer_clear(&c->output);
864 channel_close_fd(&c->sock);
866 c->type = SSH_CHANNEL_CLOSED;
867 packet_start(SSH_MSG_CHANNEL_CLOSE);
868 packet_put_int(c->remote_id);
874 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
876 int ret = x11_open_helper(&c->output);
878 c->type = SSH_CHANNEL_OPEN;
880 channel_pre_open_20(c, readset, writeset);
882 channel_pre_open_15(c, readset, writeset);
883 } else if (ret == -1) {
884 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
885 chan_read_failed(c); /** force close? */
886 chan_write_failed(c);
887 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
891 /* try to decode a socks4 header */
893 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
896 int len, have, i, found;
902 struct in_addr dest_addr;
905 debug2("channel %d: decode socks4", c->self);
907 have = buffer_len(&c->input);
908 len = sizeof(s4_req);
911 p = buffer_ptr(&c->input);
912 for (found = 0, i = len; i < have; i++) {
918 /* the peer is probably sending garbage */
919 debug("channel %d: decode socks4: too long",
926 buffer_get(&c->input, (char *)&s4_req.version, 1);
927 buffer_get(&c->input, (char *)&s4_req.command, 1);
928 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
929 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
930 have = buffer_len(&c->input);
931 p = buffer_ptr(&c->input);
933 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
935 fatal("channel %d: decode socks4: len %d > have %d",
937 strlcpy(username, p, sizeof(username));
938 buffer_consume(&c->input, len);
939 buffer_consume(&c->input, 1); /* trailing '\0' */
941 host = inet_ntoa(s4_req.dest_addr);
942 strlcpy(c->path, host, sizeof(c->path));
943 c->host_port = ntohs(s4_req.dest_port);
945 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
946 c->self, host, c->host_port, s4_req.command);
948 if (s4_req.command != 1) {
949 debug("channel %d: cannot handle: socks4 cn %d",
950 c->self, s4_req.command);
953 s4_rsp.version = 0; /* vn: 0 for reply */
954 s4_rsp.command = 90; /* cd: req granted */
955 s4_rsp.dest_port = 0; /* ignored */
956 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
957 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
961 /* dynamic port forwarding */
963 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
968 have = buffer_len(&c->input);
970 debug2("channel %d: pre_dynamic: have %d", c->self, have);
971 /* buffer_dump(&c->input); */
972 /* check if the fixed size part of the packet is in buffer. */
975 FD_SET(c->sock, readset);
978 /* try to guess the protocol */
979 p = buffer_ptr(&c->input);
982 ret = channel_decode_socks4(c, readset, writeset);
990 } else if (ret == 0) {
991 debug2("channel %d: pre_dynamic: need more", c->self);
993 FD_SET(c->sock, readset);
995 /* switch to the next state */
996 c->type = SSH_CHANNEL_OPENING;
997 port_open_helper(c, "direct-tcpip");
1001 /* This is our fake X11 server socket. */
1003 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1006 struct sockaddr addr;
1009 char buf[16384], *remote_ipaddr;
1012 if (FD_ISSET(c->sock, readset)) {
1013 debug("X11 connection requested.");
1014 addrlen = sizeof(addr);
1015 newsock = accept(c->sock, &addr, &addrlen);
1017 error("accept: %.100s", strerror(errno));
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(c->local_window_max);
1039 packet_put_int(c->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 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
1129 "forwarded-tcpip" : "direct-tcpip";
1130 nextstate = (c->host_port == 0 &&
1131 c->type != SSH_CHANNEL_RPORT_LISTENER) ?
1132 SSH_CHANNEL_DYNAMIC : SSH_CHANNEL_OPENING;
1134 addrlen = sizeof(addr);
1135 newsock = accept(c->sock, &addr, &addrlen);
1137 error("accept: %.100s", strerror(errno));
1140 nc = channel_new(rtype,
1141 nextstate, newsock, newsock, -1,
1142 c->local_window_max, c->local_maxpacket,
1143 0, xstrdup(rtype), 1);
1145 error("channel_post_port_listener: no new channel:");
1149 nc->listening_port = c->listening_port;
1150 nc->host_port = c->host_port;
1151 strlcpy(nc->path, c->path, sizeof(nc->path));
1153 if (nextstate != SSH_CHANNEL_DYNAMIC)
1154 port_open_helper(nc, rtype);
1159 * This is the authentication agent socket listening for connections from
1163 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1168 struct sockaddr addr;
1171 if (FD_ISSET(c->sock, readset)) {
1172 addrlen = sizeof(addr);
1173 newsock = accept(c->sock, &addr, &addrlen);
1175 error("accept from auth socket: %.100s", strerror(errno));
1178 name = xstrdup("accepted auth socket");
1179 nc = channel_new("accepted auth socket",
1180 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1181 c->local_window_max, c->local_maxpacket,
1184 error("channel_post_auth_listener: channel_new failed");
1189 packet_start(SSH2_MSG_CHANNEL_OPEN);
1190 packet_put_cstring("auth-agent@openssh.com");
1191 packet_put_int(nc->self);
1192 packet_put_int(c->local_window_max);
1193 packet_put_int(c->local_maxpacket);
1195 packet_start(SSH_SMSG_AGENT_OPEN);
1196 packet_put_int(nc->self);
1203 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1206 socklen_t sz = sizeof(err);
1208 if (FD_ISSET(c->sock, writeset)) {
1209 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1212 error("getsockopt SO_ERROR failed");
1215 debug("channel %d: connected", c->self);
1216 c->type = SSH_CHANNEL_OPEN;
1218 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1219 packet_put_int(c->remote_id);
1220 packet_put_int(c->self);
1221 packet_put_int(c->local_window);
1222 packet_put_int(c->local_maxpacket);
1224 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1225 packet_put_int(c->remote_id);
1226 packet_put_int(c->self);
1229 debug("channel %d: not connected: %s",
1230 c->self, strerror(err));
1232 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1233 packet_put_int(c->remote_id);
1234 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1235 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1236 packet_put_cstring(strerror(err));
1237 packet_put_cstring("");
1240 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1241 packet_put_int(c->remote_id);
1250 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1256 FD_ISSET(c->rfd, readset)) {
1257 len = read(c->rfd, buf, sizeof(buf));
1258 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1261 debug("channel %d: read<=0 rfd %d len %d",
1262 c->self, c->rfd, len);
1263 if (c->type != SSH_CHANNEL_OPEN) {
1264 debug("channel %d: not open", c->self);
1267 } else if (compat13) {
1268 buffer_consume(&c->output, buffer_len(&c->output));
1269 c->type = SSH_CHANNEL_INPUT_DRAINING;
1270 debug("channel %d: input draining.", c->self);
1272 chan_read_failed(c);
1276 if(c->input_filter != NULL) {
1277 if (c->input_filter(c, buf, len) == -1) {
1278 debug("channel %d: filter stops", c->self);
1279 chan_read_failed(c);
1282 buffer_append(&c->input, buf, len);
1288 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1293 /* Send buffered output data to the socket. */
1295 FD_ISSET(c->wfd, writeset) &&
1296 buffer_len(&c->output) > 0) {
1297 len = write(c->wfd, buffer_ptr(&c->output),
1298 buffer_len(&c->output));
1299 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1302 if (c->type != SSH_CHANNEL_OPEN) {
1303 debug("channel %d: not open", c->self);
1306 } else if (compat13) {
1307 buffer_consume(&c->output, buffer_len(&c->output));
1308 debug("channel %d: input draining.", c->self);
1309 c->type = SSH_CHANNEL_INPUT_DRAINING;
1311 chan_write_failed(c);
1315 if (compat20 && c->isatty) {
1316 if (tcgetattr(c->wfd, &tio) == 0 &&
1317 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1319 * Simulate echo to reduce the impact of
1320 * traffic analysis. We need to match the
1321 * size of a SSH2_MSG_CHANNEL_DATA message
1322 * (4 byte channel id + data)
1324 packet_send_ignore(4 + len);
1328 buffer_consume(&c->output, len);
1329 if (compat20 && len > 0) {
1330 c->local_consumed += len;
1336 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1341 /** XXX handle drain efd, too */
1343 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1344 FD_ISSET(c->efd, writeset) &&
1345 buffer_len(&c->extended) > 0) {
1346 len = write(c->efd, buffer_ptr(&c->extended),
1347 buffer_len(&c->extended));
1348 debug2("channel %d: written %d to efd %d",
1349 c->self, len, c->efd);
1350 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1353 debug2("channel %d: closing write-efd %d",
1355 channel_close_fd(&c->efd);
1357 buffer_consume(&c->extended, len);
1358 c->local_consumed += len;
1360 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1361 FD_ISSET(c->efd, readset)) {
1362 len = read(c->efd, buf, sizeof(buf));
1363 debug2("channel %d: read %d from efd %d",
1364 c->self, len, c->efd);
1365 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1368 debug2("channel %d: closing read-efd %d",
1370 channel_close_fd(&c->efd);
1372 buffer_append(&c->extended, buf, len);
1379 channel_check_window(Channel *c)
1381 if (c->type == SSH_CHANNEL_OPEN &&
1382 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1383 c->local_window < c->local_window_max/2 &&
1384 c->local_consumed > 0) {
1385 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1386 packet_put_int(c->remote_id);
1387 packet_put_int(c->local_consumed);
1389 debug2("channel %d: window %d sent adjust %d",
1390 c->self, c->local_window,
1392 c->local_window += c->local_consumed;
1393 c->local_consumed = 0;
1399 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1401 channel_handle_rfd(c, readset, writeset);
1402 channel_handle_wfd(c, readset, writeset);
1406 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1408 channel_handle_rfd(c, readset, writeset);
1409 channel_handle_wfd(c, readset, writeset);
1410 channel_handle_efd(c, readset, writeset);
1412 channel_check_window(c);
1416 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1419 /* Send buffered output data to the socket. */
1420 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1421 len = write(c->sock, buffer_ptr(&c->output),
1422 buffer_len(&c->output));
1424 buffer_consume(&c->output, buffer_len(&c->output));
1426 buffer_consume(&c->output, len);
1431 channel_handler_init_20(void)
1433 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1434 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1435 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1436 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1437 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1438 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1439 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1440 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1442 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1443 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1444 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1445 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1446 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1447 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1448 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1452 channel_handler_init_13(void)
1454 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1455 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1456 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1457 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1458 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1459 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1460 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
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_1;
1465 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1466 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1467 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1468 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1469 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1470 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1474 channel_handler_init_15(void)
1476 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1477 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
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_CONNECTING] = &channel_pre_connecting;
1482 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1484 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1485 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1486 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1487 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1488 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1489 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1493 channel_handler_init(void)
1496 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1497 channel_pre[i] = NULL;
1498 channel_post[i] = NULL;
1501 channel_handler_init_20();
1503 channel_handler_init_13();
1505 channel_handler_init_15();
1509 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1511 static int did_init = 0;
1516 channel_handler_init();
1519 for (i = 0; i < channels_alloc; i++) {
1523 if (ftab[c->type] != NULL)
1524 (*ftab[c->type])(c, readset, writeset);
1525 if (chan_is_dead(c)) {
1527 * we have to remove the fd's from the select mask
1528 * before the channels are free'd and the fd's are
1532 FD_CLR(c->wfd, writeset);
1534 FD_CLR(c->rfd, readset);
1536 if (c->extended_usage == CHAN_EXTENDED_READ)
1537 FD_CLR(c->efd, readset);
1538 if (c->extended_usage == CHAN_EXTENDED_WRITE)
1539 FD_CLR(c->efd, writeset);
1547 * Allocate/update select bitmasks and add any bits relevant to channels in
1551 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1552 int *nallocp, int rekeying)
1557 n = MAX(*maxfdp, channel_max_fd);
1559 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1560 /* perhaps check sz < nalloc/2 and shrink? */
1561 if (*readsetp == NULL || sz > *nallocp) {
1562 *readsetp = xrealloc(*readsetp, sz);
1563 *writesetp = xrealloc(*writesetp, sz);
1567 memset(*readsetp, 0, sz);
1568 memset(*writesetp, 0, sz);
1571 channel_handler(channel_pre, *readsetp, *writesetp);
1575 * After select, perform any appropriate operations for channels which have
1579 channel_after_select(fd_set * readset, fd_set * writeset)
1581 channel_handler(channel_post, readset, writeset);
1585 /* If there is data to send to the connection, enqueue some of it now. */
1588 channel_output_poll()
1593 for (i = 0; i < channels_alloc; i++) {
1599 * We are only interested in channels that can have buffered
1603 if (c->type != SSH_CHANNEL_OPEN &&
1604 c->type != SSH_CHANNEL_INPUT_DRAINING)
1607 if (c->type != SSH_CHANNEL_OPEN)
1611 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1612 /* XXX is this true? */
1613 debug2("channel %d: no data after CLOSE", c->self);
1617 /* Get the amount of buffered data for this channel. */
1618 if ((c->istate == CHAN_INPUT_OPEN ||
1619 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1620 (len = buffer_len(&c->input)) > 0) {
1622 * Send some data for the other side over the secure
1626 if (len > c->remote_window)
1627 len = c->remote_window;
1628 if (len > c->remote_maxpacket)
1629 len = c->remote_maxpacket;
1631 if (packet_is_interactive()) {
1635 /* Keep the packets at reasonable size. */
1636 if (len > packet_get_maxsize()/2)
1637 len = packet_get_maxsize()/2;
1641 packet_start(compat20 ?
1642 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1643 packet_put_int(c->remote_id);
1644 packet_put_string(buffer_ptr(&c->input), len);
1646 buffer_consume(&c->input, len);
1647 c->remote_window -= len;
1649 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1651 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1653 * input-buffer is empty and read-socket shutdown:
1654 * tell peer, that we will not send more data: send IEOF
1658 /* Send extended data, i.e. stderr */
1660 c->remote_window > 0 &&
1661 (len = buffer_len(&c->extended)) > 0 &&
1662 c->extended_usage == CHAN_EXTENDED_READ) {
1663 debug2("channel %d: rwin %d elen %d euse %d",
1664 c->self, c->remote_window, buffer_len(&c->extended),
1666 if (len > c->remote_window)
1667 len = c->remote_window;
1668 if (len > c->remote_maxpacket)
1669 len = c->remote_maxpacket;
1670 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1671 packet_put_int(c->remote_id);
1672 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1673 packet_put_string(buffer_ptr(&c->extended), len);
1675 buffer_consume(&c->extended, len);
1676 c->remote_window -= len;
1677 debug2("channel %d: sent ext data %d", c->self, len);
1683 /* -- protocol input */
1686 channel_input_data(int type, int plen, void *ctxt)
1693 /* Get the channel number and verify it. */
1694 id = packet_get_int();
1695 c = channel_lookup(id);
1697 packet_disconnect("Received data for nonexistent channel %d.", id);
1699 /* Ignore any data for non-open channels (might happen on close) */
1700 if (c->type != SSH_CHANNEL_OPEN &&
1701 c->type != SSH_CHANNEL_X11_OPEN)
1704 /* same for protocol 1.5 if output end is no longer open */
1705 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1709 data = packet_get_string(&data_len);
1713 if (data_len > c->local_maxpacket) {
1714 log("channel %d: rcvd big packet %d, maxpack %d",
1715 c->self, data_len, c->local_maxpacket);
1717 if (data_len > c->local_window) {
1718 log("channel %d: rcvd too much data %d, win %d",
1719 c->self, data_len, c->local_window);
1723 c->local_window -= data_len;
1725 packet_integrity_check(plen, 4 + 4 + data_len, type);
1727 buffer_append(&c->output, data, data_len);
1732 channel_input_extended_data(int type, int plen, void *ctxt)
1740 /* Get the channel number and verify it. */
1741 id = packet_get_int();
1742 c = channel_lookup(id);
1745 packet_disconnect("Received extended_data for bad channel %d.", id);
1746 if (c->type != SSH_CHANNEL_OPEN) {
1747 log("channel %d: ext data for non open", id);
1750 tcode = packet_get_int();
1752 c->extended_usage != CHAN_EXTENDED_WRITE ||
1753 tcode != SSH2_EXTENDED_DATA_STDERR) {
1754 log("channel %d: bad ext data", c->self);
1757 data = packet_get_string(&data_len);
1759 if (data_len > c->local_window) {
1760 log("channel %d: rcvd too much extended_data %d, win %d",
1761 c->self, data_len, c->local_window);
1765 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1766 c->local_window -= data_len;
1767 buffer_append(&c->extended, data, data_len);
1772 channel_input_ieof(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 ieof for nonexistent channel %d.", id);
1787 channel_input_close(int type, int plen, void *ctxt)
1792 packet_integrity_check(plen, 4, type);
1794 id = packet_get_int();
1795 c = channel_lookup(id);
1797 packet_disconnect("Received close for nonexistent channel %d.", id);
1800 * Send a confirmation that we have closed the channel and no more
1801 * data is coming for it.
1803 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1804 packet_put_int(c->remote_id);
1808 * If the channel is in closed state, we have sent a close request,
1809 * and the other side will eventually respond with a confirmation.
1810 * Thus, we cannot free the channel here, because then there would be
1811 * no-one to receive the confirmation. The channel gets freed when
1812 * the confirmation arrives.
1814 if (c->type != SSH_CHANNEL_CLOSED) {
1816 * Not a closed channel - mark it as draining, which will
1817 * cause it to be freed later.
1819 buffer_consume(&c->input, buffer_len(&c->input));
1820 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1824 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1826 channel_input_oclose(int type, int plen, void *ctxt)
1828 int id = packet_get_int();
1829 Channel *c = channel_lookup(id);
1830 packet_integrity_check(plen, 4, type);
1832 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1833 chan_rcvd_oclose(c);
1837 channel_input_close_confirmation(int type, int plen, void *ctxt)
1839 int id = packet_get_int();
1840 Channel *c = channel_lookup(id);
1844 packet_disconnect("Received close confirmation for "
1845 "out-of-range channel %d.", id);
1846 if (c->type != SSH_CHANNEL_CLOSED)
1847 packet_disconnect("Received close confirmation for "
1848 "non-closed channel %d (type %d).", id, c->type);
1853 channel_input_open_confirmation(int type, int plen, void *ctxt)
1859 packet_integrity_check(plen, 4 + 4, type);
1861 id = packet_get_int();
1862 c = channel_lookup(id);
1864 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1865 packet_disconnect("Received open confirmation for "
1866 "non-opening channel %d.", id);
1867 remote_id = packet_get_int();
1868 /* Record the remote channel number and mark that the channel is now open. */
1869 c->remote_id = remote_id;
1870 c->type = SSH_CHANNEL_OPEN;
1873 c->remote_window = packet_get_int();
1874 c->remote_maxpacket = packet_get_int();
1876 if (c->cb_fn != NULL && c->cb_event == type) {
1877 debug2("callback start");
1878 c->cb_fn(c->self, c->cb_arg);
1879 debug2("callback done");
1881 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1882 c->remote_window, c->remote_maxpacket);
1887 reason2txt(int reason)
1890 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1891 return "administratively prohibited";
1892 case SSH2_OPEN_CONNECT_FAILED:
1893 return "connect failed";
1894 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1895 return "unknown channel type";
1896 case SSH2_OPEN_RESOURCE_SHORTAGE:
1897 return "resource shortage";
1899 return "unknown reason";
1903 channel_input_open_failure(int type, int plen, void *ctxt)
1906 char *msg = NULL, *lang = NULL;
1910 packet_integrity_check(plen, 4, type);
1912 id = packet_get_int();
1913 c = channel_lookup(id);
1915 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1916 packet_disconnect("Received open failure for "
1917 "non-opening channel %d.", id);
1919 reason = packet_get_int();
1920 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1921 msg = packet_get_string(NULL);
1922 lang = packet_get_string(NULL);
1925 log("channel %d: open failed: %s%s%s", id,
1926 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1932 /* Free the channel. This will also close the socket. */
1937 channel_input_channel_request(int type, int plen, void *ctxt)
1942 id = packet_get_int();
1943 c = channel_lookup(id);
1946 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1947 packet_disconnect("Received request for "
1948 "non-open channel %d.", id);
1949 if (c->cb_fn != NULL && c->cb_event == type) {
1950 debug2("callback start");
1951 c->cb_fn(c->self, c->cb_arg);
1952 debug2("callback done");
1954 char *service = packet_get_string(NULL);
1955 debug("channel %d: rcvd request for %s", c->self, service);
1956 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1962 channel_input_window_adjust(int type, int plen, void *ctxt)
1970 /* Get the channel number and verify it. */
1971 id = packet_get_int();
1972 c = channel_lookup(id);
1974 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1975 log("Received window adjust for "
1976 "non-open channel %d.", id);
1979 adjust = packet_get_int();
1981 debug2("channel %d: rcvd adjust %d", id, adjust);
1982 c->remote_window += adjust;
1986 channel_input_port_open(int type, int plen, void *ctxt)
1990 char *host, *originator_string;
1991 int remote_id, sock = -1;
1993 remote_id = packet_get_int();
1994 host = packet_get_string(NULL);
1995 host_port = packet_get_int();
1997 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
1998 originator_string = packet_get_string(NULL);
2000 originator_string = xstrdup("unknown (remote did not supply name)");
2003 sock = channel_connect_to(host, host_port);
2005 c = channel_new("connected socket",
2006 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2007 originator_string, 1);
2009 error("channel_input_port_open: channel_new failed");
2012 c->remote_id = remote_id;
2016 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2017 packet_put_int(remote_id);
2024 /* -- tcp forwarding */
2027 * Initiate forwarding of connections to local port "port" through the secure
2028 * channel to host:port from remote side.
2031 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2032 u_short port_to_connect, int gateway_ports)
2034 return channel_request_forwarding(
2036 host_to_connect, port_to_connect,
2037 gateway_ports, /*remote_fwd*/ 0);
2041 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2042 * (SSH_CHANNEL_RPORT_LISTENER).
2045 channel_request_forwarding(
2046 const char *listen_address, u_short listen_port,
2047 const char *host_to_connect, u_short port_to_connect,
2048 int gateway_ports, int remote_fwd)
2051 int success, sock, on = 1, type;
2052 struct addrinfo hints, *ai, *aitop;
2053 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2055 struct linger linger;
2060 host = listen_address;
2061 type = SSH_CHANNEL_RPORT_LISTENER;
2063 host = host_to_connect;
2064 type = SSH_CHANNEL_PORT_LISTENER;
2067 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2068 error("Forward host name too long.");
2072 /* XXX listen_address is currently ignored */
2074 * getaddrinfo returns a loopback address if the hostname is
2075 * set to NULL and hints.ai_flags is not AI_PASSIVE
2077 memset(&hints, 0, sizeof(hints));
2078 hints.ai_family = IPv4or6;
2079 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2080 hints.ai_socktype = SOCK_STREAM;
2081 snprintf(strport, sizeof strport, "%d", listen_port);
2082 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2083 packet_disconnect("getaddrinfo: fatal error");
2085 for (ai = aitop; ai; ai = ai->ai_next) {
2086 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2088 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2089 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2090 error("channel_request_forwarding: getnameinfo failed");
2093 /* Create a port to listen for the host. */
2094 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2096 /* this is no error since kernel may not support ipv6 */
2097 verbose("socket: %.100s", strerror(errno));
2101 * Set socket options. We would like the socket to disappear
2102 * as soon as it has been closed for whatever reason.
2104 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2106 linger.l_linger = 5;
2107 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2108 debug("Local forwarding listening on %s port %s.", ntop, strport);
2110 /* Bind the socket to the address. */
2111 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2112 /* address can be in use ipv6 address is already bound */
2114 error("bind: %.100s", strerror(errno));
2116 verbose("bind: %.100s", strerror(errno));
2121 /* Start listening for connections on the socket. */
2122 if (listen(sock, 5) < 0) {
2123 error("listen: %.100s", strerror(errno));
2127 /* Allocate a channel number for the socket. */
2128 c = channel_new("port listener", type, sock, sock, -1,
2129 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2130 0, xstrdup("port listener"), 1);
2132 error("channel_request_forwarding: channel_new failed");
2136 strlcpy(c->path, host, sizeof(c->path));
2137 c->host_port = port_to_connect;
2138 c->listening_port = listen_port;
2142 error("channel_request_forwarding: cannot listen to port: %d",
2144 freeaddrinfo(aitop);
2149 * Initiate forwarding of connections to port "port" on remote host through
2150 * the secure channel to host:port from local side.
2154 channel_request_remote_forwarding(u_short listen_port,
2155 const char *host_to_connect, u_short port_to_connect)
2157 int payload_len, type, success = 0;
2159 /* Record locally that connection to this host/port is permitted. */
2160 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2161 fatal("channel_request_remote_forwarding: too many forwards");
2163 /* Send the forward request to the remote side. */
2165 const char *address_to_bind = "0.0.0.0";
2166 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2167 packet_put_cstring("tcpip-forward");
2168 packet_put_char(0); /* boolean: want reply */
2169 packet_put_cstring(address_to_bind);
2170 packet_put_int(listen_port);
2172 packet_write_wait();
2173 /* Assume that server accepts the request */
2176 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2177 packet_put_int(listen_port);
2178 packet_put_cstring(host_to_connect);
2179 packet_put_int(port_to_connect);
2181 packet_write_wait();
2183 /* Wait for response from the remote side. */
2184 type = packet_read(&payload_len);
2186 case SSH_SMSG_SUCCESS:
2189 case SSH_SMSG_FAILURE:
2190 log("Warning: Server denied remote port forwarding.");
2193 /* Unknown packet */
2194 packet_disconnect("Protocol error for port forward request:"
2195 "received packet type %d.", type);
2199 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2200 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2201 permitted_opens[num_permitted_opens].listen_port = listen_port;
2202 num_permitted_opens++;
2207 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2208 * listening for the port, and sends back a success reply (or disconnect
2209 * message if there was an error). This never returns if there was an error.
2213 channel_input_port_forward_request(int is_root, int gateway_ports)
2215 u_short port, host_port;
2218 /* Get arguments from the packet. */
2219 port = packet_get_int();
2220 hostname = packet_get_string(NULL);
2221 host_port = packet_get_int();
2225 * Check that an unprivileged user is not trying to forward a
2228 if (port < IPPORT_RESERVED && !is_root)
2229 packet_disconnect("Requested forwarding of port %d but user is not root.",
2232 /* Initiate forwarding */
2233 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2235 /* Free the argument string. */
2240 * Permits opening to any host/port if permitted_opens[] is empty. This is
2241 * usually called by the server, because the user could connect to any port
2242 * anyway, and the server has no way to know but to trust the client anyway.
2245 channel_permit_all_opens()
2247 if (num_permitted_opens == 0)
2248 all_opens_permitted = 1;
2252 channel_add_permitted_opens(char *host, int port)
2254 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2255 fatal("channel_request_remote_forwarding: too many forwards");
2256 debug("allow port forwarding to host %s port %d", host, port);
2258 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2259 permitted_opens[num_permitted_opens].port_to_connect = port;
2260 num_permitted_opens++;
2262 all_opens_permitted = 0;
2266 channel_clear_permitted_opens(void)
2270 for (i = 0; i < num_permitted_opens; i++)
2271 xfree(permitted_opens[i].host_to_connect);
2272 num_permitted_opens = 0;
2277 /* return socket to remote host, port */
2279 connect_to(const char *host, u_short port)
2281 struct addrinfo hints, *ai, *aitop;
2282 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2286 memset(&hints, 0, sizeof(hints));
2287 hints.ai_family = IPv4or6;
2288 hints.ai_socktype = SOCK_STREAM;
2289 snprintf(strport, sizeof strport, "%d", port);
2290 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2291 error("connect_to %.100s: unknown host (%s)", host,
2292 gai_strerror(gaierr));
2295 for (ai = aitop; ai; ai = ai->ai_next) {
2296 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2298 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2299 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2300 error("connect_to: getnameinfo failed");
2303 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2305 error("socket: %.100s", strerror(errno));
2308 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2309 fatal("connect_to: F_SETFL: %s", strerror(errno));
2310 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2311 errno != EINPROGRESS) {
2312 error("connect_to %.100s port %s: %.100s", ntop, strport,
2315 continue; /* fail -- try next */
2317 break; /* success */
2320 freeaddrinfo(aitop);
2322 error("connect_to %.100s port %d: failed.", host, port);
2330 channel_connect_by_listen_address(u_short listen_port)
2334 for (i = 0; i < num_permitted_opens; i++)
2335 if (permitted_opens[i].listen_port == listen_port)
2337 permitted_opens[i].host_to_connect,
2338 permitted_opens[i].port_to_connect);
2339 error("WARNING: Server requests forwarding for unknown listen_port %d",
2344 /* Check if connecting to that port is permitted and connect. */
2346 channel_connect_to(const char *host, u_short port)
2350 permit = all_opens_permitted;
2352 for (i = 0; i < num_permitted_opens; i++)
2353 if (permitted_opens[i].port_to_connect == port &&
2354 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2359 log("Received request to connect to host %.100s port %d, "
2360 "but the request was denied.", host, port);
2363 return connect_to(host, port);
2366 /* -- X11 forwarding */
2369 * Creates an internet domain socket for listening for X11 connections.
2370 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2374 x11_create_display_inet(int screen_number, int x11_display_offset)
2376 int display_number, sock;
2378 struct addrinfo hints, *ai, *aitop;
2379 char strport[NI_MAXSERV];
2380 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2382 char hostname[MAXHOSTNAMELEN];
2384 for (display_number = x11_display_offset;
2385 display_number < MAX_DISPLAYS;
2387 port = 6000 + display_number;
2388 memset(&hints, 0, sizeof(hints));
2389 hints.ai_family = IPv4or6;
2390 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2391 hints.ai_socktype = SOCK_STREAM;
2392 snprintf(strport, sizeof strport, "%d", port);
2393 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2394 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2397 for (ai = aitop; ai; ai = ai->ai_next) {
2398 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2400 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2402 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2403 error("socket: %.100s", strerror(errno));
2406 debug("x11_create_display_inet: Socket family %d not supported",
2411 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2412 debug("bind port %d: %.100s", port, strerror(errno));
2413 shutdown(sock, SHUT_RDWR);
2419 for (n = 0; n < num_socks; n++) {
2420 shutdown(socks[n], SHUT_RDWR);
2426 socks[num_socks++] = sock;
2427 #ifndef DONT_TRY_OTHER_AF
2428 if (num_socks == NUM_SOCKS)
2434 freeaddrinfo(aitop);
2438 if (display_number >= MAX_DISPLAYS) {
2439 error("Failed to allocate internet-domain X11 display socket.");
2442 /* Start listening for connections on the socket. */
2443 for (n = 0; n < num_socks; n++) {
2445 if (listen(sock, 5) < 0) {
2446 error("listen: %.100s", strerror(errno));
2447 shutdown(sock, SHUT_RDWR);
2453 /* Set up a suitable value for the DISPLAY variable. */
2454 if (gethostname(hostname, sizeof(hostname)) < 0)
2455 fatal("gethostname: %.100s", strerror(errno));
2457 #ifdef IPADDR_IN_DISPLAY
2459 * HPUX detects the local hostname in the DISPLAY variable and tries
2460 * to set up a shared memory connection to the server, which it
2461 * incorrectly supposes to be local.
2463 * The workaround - as used in later $$H and other programs - is
2464 * is to set display to the host's IP address.
2468 struct in_addr my_addr;
2470 he = gethostbyname(hostname);
2472 error("[X11-broken-fwd-hostname-workaround] Could not get "
2473 "IP address for hostname %s.", hostname);
2475 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2476 "Could not get IP address for hostname %s.", hostname);
2478 shutdown(sock, SHUT_RDWR);
2484 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2486 /* Set DISPLAY to <ip address>:screen.display */
2487 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2488 display_number, screen_number);
2490 #else /* IPADDR_IN_DISPLAY */
2491 /* Just set DISPLAY to hostname:screen.display */
2492 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2493 display_number, screen_number);
2494 #endif /* IPADDR_IN_DISPLAY */
2496 /* Allocate a channel for each socket. */
2497 for (n = 0; n < num_socks; n++) {
2499 (void) channel_new("x11 listener",
2500 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2501 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2502 0, xstrdup("X11 inet listener"), 1);
2505 /* Return a suitable value for the DISPLAY environment variable. */
2506 return xstrdup(display);
2510 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2514 connect_local_xsocket(u_int dnr)
2516 static const char *const x_sockets[] = {
2518 "/var/X/.X11-unix/X" "%u",
2519 "/usr/spool/sockets/X11/" "%u",
2523 struct sockaddr_un addr;
2524 const char *const * path;
2526 for (path = x_sockets; *path; ++path) {
2527 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2529 error("socket: %.100s", strerror(errno));
2530 memset(&addr, 0, sizeof(addr));
2531 addr.sun_family = AF_UNIX;
2532 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2533 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2537 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2542 x11_connect_display(void)
2544 int display_number, sock = 0;
2545 const char *display;
2546 char buf[1024], *cp;
2547 struct addrinfo hints, *ai, *aitop;
2548 char strport[NI_MAXSERV];
2551 /* Try to open a socket for the local X server. */
2552 display = getenv("DISPLAY");
2554 error("DISPLAY not set.");
2558 * Now we decode the value of the DISPLAY variable and make a
2559 * connection to the real X server.
2563 * Check if it is a unix domain socket. Unix domain displays are in
2564 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2566 if (strncmp(display, "unix:", 5) == 0 ||
2567 display[0] == ':') {
2568 /* Connect to the unix domain socket. */
2569 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2570 error("Could not parse display number from DISPLAY: %.100s",
2574 /* Create a socket. */
2575 sock = connect_local_xsocket(display_number);
2579 /* OK, we now have a connection to the display. */
2583 * Connect to an inet socket. The DISPLAY value is supposedly
2584 * hostname:d[.s], where hostname may also be numeric IP address.
2586 strncpy(buf, display, sizeof(buf));
2587 buf[sizeof(buf) - 1] = 0;
2588 cp = strchr(buf, ':');
2590 error("Could not find ':' in DISPLAY: %.100s", display);
2594 /* buf now contains the host name. But first we parse the display number. */
2595 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2596 error("Could not parse display number from DISPLAY: %.100s",
2601 /* Look up the host address */
2602 memset(&hints, 0, sizeof(hints));
2603 hints.ai_family = IPv4or6;
2604 hints.ai_socktype = SOCK_STREAM;
2605 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2606 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2607 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2610 for (ai = aitop; ai; ai = ai->ai_next) {
2611 /* Create a socket. */
2612 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2614 debug("socket: %.100s", strerror(errno));
2617 /* Connect it to the display. */
2618 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2619 debug("connect %.100s port %d: %.100s", buf,
2620 6000 + display_number, strerror(errno));
2627 freeaddrinfo(aitop);
2629 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2637 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2638 * the remote channel number. We should do whatever we want, and respond
2639 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2643 x11_input_open(int type, int plen, void *ctxt)
2646 int remote_id, sock = 0;
2649 debug("Received X11 open request.");
2651 remote_id = packet_get_int();
2653 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2654 remote_host = packet_get_string(NULL);
2656 remote_host = xstrdup("unknown (remote did not supply name)");
2660 /* Obtain a connection to the real X display. */
2661 sock = x11_connect_display();
2663 /* Allocate a channel for this connection. */
2664 c = channel_new("connected x11 socket",
2665 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2668 error("x11_input_open: channel_new failed");
2671 c->remote_id = remote_id;
2675 /* Send refusal to the remote host. */
2676 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2677 packet_put_int(remote_id);
2679 /* Send a confirmation to the remote host. */
2680 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2681 packet_put_int(remote_id);
2682 packet_put_int(c->self);
2687 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2689 deny_input_open(int type, int plen, void *ctxt)
2691 int rchan = packet_get_int();
2693 case SSH_SMSG_AGENT_OPEN:
2694 error("Warning: ssh server tried agent forwarding.");
2696 case SSH_SMSG_X11_OPEN:
2697 error("Warning: ssh server tried X11 forwarding.");
2700 error("deny_input_open: type %d plen %d", type, plen);
2703 error("Warning: this is probably a break in attempt by a malicious server.");
2704 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2705 packet_put_int(rchan);
2710 * Requests forwarding of X11 connections, generates fake authentication
2711 * data, and enables authentication spoofing.
2712 * This should be called in the client only.
2715 x11_request_forwarding_with_spoofing(int client_session_id,
2716 const char *proto, const char *data)
2718 u_int data_len = (u_int) strlen(data) / 2;
2719 u_int i, value, len;
2725 cp = getenv("DISPLAY");
2727 cp = strchr(cp, ':');
2729 cp = strchr(cp, '.');
2731 screen_number = atoi(cp + 1);
2735 /* Save protocol name. */
2736 x11_saved_proto = xstrdup(proto);
2739 * Extract real authentication data and generate fake data of the
2742 x11_saved_data = xmalloc(data_len);
2743 x11_fake_data = xmalloc(data_len);
2744 for (i = 0; i < data_len; i++) {
2745 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2746 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2748 rand = arc4random();
2749 x11_saved_data[i] = value;
2750 x11_fake_data[i] = rand & 0xff;
2753 x11_saved_data_len = data_len;
2754 x11_fake_data_len = data_len;
2756 /* Convert the fake data into hex. */
2757 len = 2 * data_len + 1;
2758 new_data = xmalloc(len);
2759 for (i = 0; i < data_len; i++)
2760 snprintf(new_data + 2 * i, len - 2 * i,
2761 "%02x", (u_char) x11_fake_data[i]);
2763 /* Send the request packet. */
2765 channel_request_start(client_session_id, "x11-req", 0);
2766 packet_put_char(0); /* XXX bool single connection */
2768 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2770 packet_put_cstring(proto);
2771 packet_put_cstring(new_data);
2772 packet_put_int(screen_number);
2774 packet_write_wait();
2779 /* -- agent forwarding */
2781 /* Sends a message to the server to request authentication fd forwarding. */
2784 auth_request_forwarding()
2786 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2788 packet_write_wait();
2792 * Returns the name of the forwarded authentication socket. Returns NULL if
2793 * there is no forwarded authentication socket. The returned value points to
2798 auth_get_socket_name()
2800 return auth_sock_name;
2803 /* removes the agent forwarding socket */
2806 auth_sock_cleanup_proc(void *_pw)
2808 struct passwd *pw = _pw;
2810 if (auth_sock_name) {
2811 temporarily_use_uid(pw);
2812 unlink(auth_sock_name);
2813 rmdir(auth_sock_dir);
2814 auth_sock_name = NULL;
2820 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2821 * This starts forwarding authentication requests.
2825 auth_input_request_forwarding(struct passwd * pw)
2829 struct sockaddr_un sunaddr;
2831 if (auth_get_socket_name() != NULL) {
2832 error("authentication forwarding requested twice.");
2836 /* Temporarily drop privileged uid for mkdir/bind. */
2837 temporarily_use_uid(pw);
2839 /* Allocate a buffer for the socket name, and format the name. */
2840 auth_sock_name = xmalloc(MAXPATHLEN);
2841 auth_sock_dir = xmalloc(MAXPATHLEN);
2842 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2844 /* Create private directory for socket */
2845 if (mkdtemp(auth_sock_dir) == NULL) {
2846 packet_send_debug("Agent forwarding disabled: "
2847 "mkdtemp() failed: %.100s", strerror(errno));
2849 xfree(auth_sock_name);
2850 xfree(auth_sock_dir);
2851 auth_sock_name = NULL;
2852 auth_sock_dir = NULL;
2855 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2856 auth_sock_dir, (int) getpid());
2858 /* delete agent socket on fatal() */
2859 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2861 /* Create the socket. */
2862 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2864 packet_disconnect("socket: %.100s", strerror(errno));
2866 /* Bind it to the name. */
2867 memset(&sunaddr, 0, sizeof(sunaddr));
2868 sunaddr.sun_family = AF_UNIX;
2869 strncpy(sunaddr.sun_path, auth_sock_name,
2870 sizeof(sunaddr.sun_path));
2872 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2873 packet_disconnect("bind: %.100s", strerror(errno));
2875 /* Restore the privileged uid. */
2878 /* Start listening on the socket. */
2879 if (listen(sock, 5) < 0)
2880 packet_disconnect("listen: %.100s", strerror(errno));
2882 /* Allocate a channel for the authentication agent socket. */
2883 nc = channel_new("auth socket",
2884 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2885 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2886 0, xstrdup("auth socket"), 1);
2888 error("auth_input_request_forwarding: channel_new failed");
2889 auth_sock_cleanup_proc(pw);
2890 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2894 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2898 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2901 auth_input_open_request(int type, int plen, void *ctxt)
2904 int remote_id, sock;
2907 packet_integrity_check(plen, 4, type);
2909 /* Read the remote channel number from the message. */
2910 remote_id = packet_get_int();
2913 * Get a connection to the local authentication agent (this may again
2916 sock = ssh_get_authentication_socket();
2919 * If we could not connect the agent, send an error message back to
2920 * the server. This should never happen unless the agent dies,
2921 * because authentication forwarding is only enabled if we have an
2925 name = xstrdup("authentication agent connection");
2926 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2927 -1, 0, 0, 0, name, 1);
2929 error("auth_input_open_request: channel_new failed");
2933 c->remote_id = remote_id;
2937 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2938 packet_put_int(remote_id);
2940 /* Send a confirmation to the remote host. */
2941 debug("Forwarding authentication connection.");
2942 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2943 packet_put_int(remote_id);
2944 packet_put_int(c->self);