2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
15 * SSH2 support added by Markus Friedl.
16 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 RCSID("$OpenBSD: channels.c,v 1.158 2002/01/09 17:26:35 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(Channel *c, fd_set * readset, fd_set * writeset)
708 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
710 if (c->istate == CHAN_INPUT_OPEN &&
712 buffer_len(&c->input) < limit)
713 FD_SET(c->rfd, readset);
714 if (c->ostate == CHAN_OUTPUT_OPEN ||
715 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
716 if (buffer_len(&c->output) > 0) {
717 FD_SET(c->wfd, writeset);
718 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
722 /** XXX check close conditions, too */
723 if (compat20 && c->efd != -1) {
724 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
725 buffer_len(&c->extended) > 0)
726 FD_SET(c->efd, writeset);
727 else if (c->extended_usage == CHAN_EXTENDED_READ &&
728 buffer_len(&c->extended) < c->remote_window)
729 FD_SET(c->efd, readset);
734 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
736 if (buffer_len(&c->input) == 0) {
737 packet_start(SSH_MSG_CHANNEL_CLOSE);
738 packet_put_int(c->remote_id);
740 c->type = SSH_CHANNEL_CLOSED;
741 debug("channel %d: closing after input drain.", c->self);
746 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
748 if (buffer_len(&c->output) == 0)
751 FD_SET(c->sock, writeset);
755 * This is a special state for X11 authentication spoofing. An opened X11
756 * connection (when authentication spoofing is being done) remains in this
757 * state until the first packet has been completely read. The authentication
758 * data in that packet is then substituted by the real data if it matches the
759 * fake data, and the channel is put into normal mode.
760 * XXX All this happens at the client side.
761 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
764 x11_open_helper(Buffer *b)
767 u_int proto_len, data_len;
769 /* Check if the fixed size part of the packet is in buffer. */
770 if (buffer_len(b) < 12)
773 /* Parse the lengths of variable-length fields. */
775 if (ucp[0] == 0x42) { /* Byte order MSB first. */
776 proto_len = 256 * ucp[6] + ucp[7];
777 data_len = 256 * ucp[8] + ucp[9];
778 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
779 proto_len = ucp[6] + 256 * ucp[7];
780 data_len = ucp[8] + 256 * ucp[9];
782 debug("Initial X11 packet contains bad byte order byte: 0x%x",
787 /* Check if the whole packet is in buffer. */
789 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
792 /* Check if authentication protocol matches. */
793 if (proto_len != strlen(x11_saved_proto) ||
794 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
795 debug("X11 connection uses different authentication protocol.");
798 /* Check if authentication data matches our fake data. */
799 if (data_len != x11_fake_data_len ||
800 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
801 x11_fake_data, x11_fake_data_len) != 0) {
802 debug("X11 auth data does not match fake data.");
805 /* Check fake data length */
806 if (x11_fake_data_len != x11_saved_data_len) {
807 error("X11 fake_data_len %d != saved_data_len %d",
808 x11_fake_data_len, x11_saved_data_len);
812 * Received authentication protocol and data match
813 * our fake data. Substitute the fake data with real
816 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
817 x11_saved_data, x11_saved_data_len);
822 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
824 int ret = x11_open_helper(&c->output);
826 /* Start normal processing for the channel. */
827 c->type = SSH_CHANNEL_OPEN;
828 channel_pre_open_13(c, readset, writeset);
829 } else if (ret == -1) {
831 * We have received an X11 connection that has bad
832 * authentication information.
834 log("X11 connection rejected because of wrong authentication.");
835 buffer_clear(&c->input);
836 buffer_clear(&c->output);
837 channel_close_fd(&c->sock);
839 c->type = SSH_CHANNEL_CLOSED;
840 packet_start(SSH_MSG_CHANNEL_CLOSE);
841 packet_put_int(c->remote_id);
847 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
849 int ret = x11_open_helper(&c->output);
851 /* c->force_drain = 1; */
854 c->type = SSH_CHANNEL_OPEN;
855 channel_pre_open(c, readset, writeset);
856 } else if (ret == -1) {
857 log("X11 connection rejected because of wrong authentication.");
858 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
860 buffer_clear(&c->input);
862 buffer_clear(&c->output);
863 /* for proto v1, the peer will send an IEOF */
865 chan_write_failed(c);
867 c->type = SSH_CHANNEL_OPEN;
868 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
872 /* try to decode a socks4 header */
874 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
877 int len, have, i, found;
883 struct in_addr dest_addr;
886 debug2("channel %d: decode socks4", c->self);
888 have = buffer_len(&c->input);
889 len = sizeof(s4_req);
892 p = buffer_ptr(&c->input);
893 for (found = 0, i = len; i < have; i++) {
899 /* the peer is probably sending garbage */
900 debug("channel %d: decode socks4: too long",
907 buffer_get(&c->input, (char *)&s4_req.version, 1);
908 buffer_get(&c->input, (char *)&s4_req.command, 1);
909 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
910 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
911 have = buffer_len(&c->input);
912 p = buffer_ptr(&c->input);
914 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
916 fatal("channel %d: decode socks4: len %d > have %d",
918 strlcpy(username, p, sizeof(username));
919 buffer_consume(&c->input, len);
920 buffer_consume(&c->input, 1); /* trailing '\0' */
922 host = inet_ntoa(s4_req.dest_addr);
923 strlcpy(c->path, host, sizeof(c->path));
924 c->host_port = ntohs(s4_req.dest_port);
926 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
927 c->self, host, c->host_port, s4_req.command);
929 if (s4_req.command != 1) {
930 debug("channel %d: cannot handle: socks4 cn %d",
931 c->self, s4_req.command);
934 s4_rsp.version = 0; /* vn: 0 for reply */
935 s4_rsp.command = 90; /* cd: req granted */
936 s4_rsp.dest_port = 0; /* ignored */
937 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
938 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
942 /* dynamic port forwarding */
944 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
949 have = buffer_len(&c->input);
951 debug2("channel %d: pre_dynamic: have %d", c->self, have);
952 /* buffer_dump(&c->input); */
953 /* check if the fixed size part of the packet is in buffer. */
956 FD_SET(c->sock, readset);
959 /* try to guess the protocol */
960 p = buffer_ptr(&c->input);
963 ret = channel_decode_socks4(c, readset, writeset);
971 } else if (ret == 0) {
972 debug2("channel %d: pre_dynamic: need more", c->self);
974 FD_SET(c->sock, readset);
976 /* switch to the next state */
977 c->type = SSH_CHANNEL_OPENING;
978 port_open_helper(c, "direct-tcpip");
982 /* This is our fake X11 server socket. */
984 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
987 struct sockaddr addr;
990 char buf[16384], *remote_ipaddr;
993 if (FD_ISSET(c->sock, readset)) {
994 debug("X11 connection requested.");
995 addrlen = sizeof(addr);
996 newsock = accept(c->sock, &addr, &addrlen);
997 if (c->single_connection) {
998 debug("single_connection: closing X11 listener.");
999 channel_close_fd(&c->sock);
1003 error("accept: %.100s", strerror(errno));
1006 if (setsockopt(newsock, IPPROTO_TCP, TCP_NODELAY, &on,
1008 error("setsockopt TCP_NODELAY: %.100s",
1010 remote_ipaddr = get_peer_ipaddr(newsock);
1011 remote_port = get_peer_port(newsock);
1012 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1013 remote_ipaddr, remote_port);
1015 nc = channel_new("accepted x11 socket",
1016 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1017 c->local_window_max, c->local_maxpacket,
1018 0, xstrdup(buf), 1);
1021 xfree(remote_ipaddr);
1025 packet_start(SSH2_MSG_CHANNEL_OPEN);
1026 packet_put_cstring("x11");
1027 packet_put_int(nc->self);
1028 packet_put_int(nc->local_window_max);
1029 packet_put_int(nc->local_maxpacket);
1030 /* originator ipaddr and port */
1031 packet_put_cstring(remote_ipaddr);
1032 if (datafellows & SSH_BUG_X11FWD) {
1033 debug("ssh2 x11 bug compat mode");
1035 packet_put_int(remote_port);
1039 packet_start(SSH_SMSG_X11_OPEN);
1040 packet_put_int(nc->self);
1041 if (packet_get_protocol_flags() &
1042 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1043 packet_put_cstring(buf);
1046 xfree(remote_ipaddr);
1051 port_open_helper(Channel *c, char *rtype)
1055 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1056 u_short remote_port = get_peer_port(c->sock);
1058 direct = (strcmp(rtype, "direct-tcpip") == 0);
1060 snprintf(buf, sizeof buf,
1061 "%s: listening port %d for %.100s port %d, "
1062 "connect from %.200s port %d",
1063 rtype, c->listening_port, c->path, c->host_port,
1064 remote_ipaddr, remote_port);
1066 xfree(c->remote_name);
1067 c->remote_name = xstrdup(buf);
1070 packet_start(SSH2_MSG_CHANNEL_OPEN);
1071 packet_put_cstring(rtype);
1072 packet_put_int(c->self);
1073 packet_put_int(c->local_window_max);
1074 packet_put_int(c->local_maxpacket);
1076 /* target host, port */
1077 packet_put_cstring(c->path);
1078 packet_put_int(c->host_port);
1080 /* listen address, port */
1081 packet_put_cstring(c->path);
1082 packet_put_int(c->listening_port);
1084 /* originator host and port */
1085 packet_put_cstring(remote_ipaddr);
1086 packet_put_int(remote_port);
1089 packet_start(SSH_MSG_PORT_OPEN);
1090 packet_put_int(c->self);
1091 packet_put_cstring(c->path);
1092 packet_put_int(c->host_port);
1093 if (packet_get_protocol_flags() &
1094 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1095 packet_put_cstring(c->remote_name);
1098 xfree(remote_ipaddr);
1102 * This socket is listening for connections to a forwarded TCP/IP port.
1105 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1108 struct sockaddr addr;
1109 int newsock, nextstate;
1113 if (FD_ISSET(c->sock, readset)) {
1114 debug("Connection to port %d forwarding "
1115 "to %.100s port %d requested.",
1116 c->listening_port, c->path, c->host_port);
1118 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1119 nextstate = SSH_CHANNEL_OPENING;
1120 rtype = "forwarded-tcpip";
1122 if (c->host_port == 0) {
1123 nextstate = SSH_CHANNEL_DYNAMIC;
1124 rtype = "dynamic-tcpip";
1126 nextstate = SSH_CHANNEL_OPENING;
1127 rtype = "direct-tcpip";
1131 addrlen = sizeof(addr);
1132 newsock = accept(c->sock, &addr, &addrlen);
1134 error("accept: %.100s", strerror(errno));
1137 nc = channel_new(rtype,
1138 nextstate, newsock, newsock, -1,
1139 c->local_window_max, c->local_maxpacket,
1140 0, xstrdup(rtype), 1);
1142 error("channel_post_port_listener: no new channel:");
1146 nc->listening_port = c->listening_port;
1147 nc->host_port = c->host_port;
1148 strlcpy(nc->path, c->path, sizeof(nc->path));
1150 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1152 * do not call the channel_post handler until
1153 * this flag has been reset by a pre-handler.
1154 * otherwise the FD_ISSET calls might overflow
1158 port_open_helper(nc, rtype);
1164 * This is the authentication agent socket listening for connections from
1168 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1173 struct sockaddr addr;
1176 if (FD_ISSET(c->sock, readset)) {
1177 addrlen = sizeof(addr);
1178 newsock = accept(c->sock, &addr, &addrlen);
1180 error("accept from auth socket: %.100s", strerror(errno));
1183 name = xstrdup("accepted auth socket");
1184 nc = channel_new("accepted auth socket",
1185 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1186 c->local_window_max, c->local_maxpacket,
1189 error("channel_post_auth_listener: channel_new failed");
1194 packet_start(SSH2_MSG_CHANNEL_OPEN);
1195 packet_put_cstring("auth-agent@openssh.com");
1196 packet_put_int(nc->self);
1197 packet_put_int(c->local_window_max);
1198 packet_put_int(c->local_maxpacket);
1200 packet_start(SSH_SMSG_AGENT_OPEN);
1201 packet_put_int(nc->self);
1208 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1211 socklen_t sz = sizeof(err);
1213 if (FD_ISSET(c->sock, writeset)) {
1214 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1217 error("getsockopt SO_ERROR failed");
1220 debug("channel %d: connected", c->self);
1221 c->type = SSH_CHANNEL_OPEN;
1223 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1224 packet_put_int(c->remote_id);
1225 packet_put_int(c->self);
1226 packet_put_int(c->local_window);
1227 packet_put_int(c->local_maxpacket);
1229 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1230 packet_put_int(c->remote_id);
1231 packet_put_int(c->self);
1234 debug("channel %d: not connected: %s",
1235 c->self, strerror(err));
1237 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1238 packet_put_int(c->remote_id);
1239 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1240 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1241 packet_put_cstring(strerror(err));
1242 packet_put_cstring("");
1245 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1246 packet_put_int(c->remote_id);
1255 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1261 FD_ISSET(c->rfd, readset)) {
1262 len = read(c->rfd, buf, sizeof(buf));
1263 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1266 debug("channel %d: read<=0 rfd %d len %d",
1267 c->self, c->rfd, len);
1268 if (c->type != SSH_CHANNEL_OPEN) {
1269 debug("channel %d: not open", c->self);
1272 } else if (compat13) {
1273 buffer_clear(&c->output);
1274 c->type = SSH_CHANNEL_INPUT_DRAINING;
1275 debug("channel %d: input draining.", c->self);
1277 chan_read_failed(c);
1281 if (c->input_filter != NULL) {
1282 if (c->input_filter(c, buf, len) == -1) {
1283 debug("channel %d: filter stops", c->self);
1284 chan_read_failed(c);
1287 buffer_append(&c->input, buf, len);
1293 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1300 /* Send buffered output data to the socket. */
1302 FD_ISSET(c->wfd, writeset) &&
1303 buffer_len(&c->output) > 0) {
1304 data = buffer_ptr(&c->output);
1305 dlen = buffer_len(&c->output);
1306 len = write(c->wfd, data, dlen);
1307 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1310 if (c->type != SSH_CHANNEL_OPEN) {
1311 debug("channel %d: not open", c->self);
1314 } else if (compat13) {
1315 buffer_clear(&c->output);
1316 debug("channel %d: input draining.", c->self);
1317 c->type = SSH_CHANNEL_INPUT_DRAINING;
1319 chan_write_failed(c);
1323 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1324 if (tcgetattr(c->wfd, &tio) == 0 &&
1325 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1327 * Simulate echo to reduce the impact of
1328 * traffic analysis. We need to match the
1329 * size of a SSH2_MSG_CHANNEL_DATA message
1330 * (4 byte channel id + data)
1332 packet_send_ignore(4 + len);
1336 buffer_consume(&c->output, len);
1337 if (compat20 && len > 0) {
1338 c->local_consumed += len;
1344 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1349 /** XXX handle drain efd, too */
1351 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1352 FD_ISSET(c->efd, writeset) &&
1353 buffer_len(&c->extended) > 0) {
1354 len = write(c->efd, buffer_ptr(&c->extended),
1355 buffer_len(&c->extended));
1356 debug2("channel %d: written %d to efd %d",
1357 c->self, len, c->efd);
1358 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1361 debug2("channel %d: closing write-efd %d",
1363 channel_close_fd(&c->efd);
1365 buffer_consume(&c->extended, len);
1366 c->local_consumed += len;
1368 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1369 FD_ISSET(c->efd, readset)) {
1370 len = read(c->efd, buf, sizeof(buf));
1371 debug2("channel %d: read %d from efd %d",
1372 c->self, len, c->efd);
1373 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1376 debug2("channel %d: closing read-efd %d",
1378 channel_close_fd(&c->efd);
1380 buffer_append(&c->extended, buf, len);
1387 channel_check_window(Channel *c)
1389 if (c->type == SSH_CHANNEL_OPEN &&
1390 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1391 c->local_window < c->local_window_max/2 &&
1392 c->local_consumed > 0) {
1393 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1394 packet_put_int(c->remote_id);
1395 packet_put_int(c->local_consumed);
1397 debug2("channel %d: window %d sent adjust %d",
1398 c->self, c->local_window,
1400 c->local_window += c->local_consumed;
1401 c->local_consumed = 0;
1407 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1411 channel_handle_rfd(c, readset, writeset);
1412 channel_handle_wfd(c, readset, writeset);
1415 channel_handle_efd(c, readset, writeset);
1416 channel_check_window(c);
1420 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1423 /* Send buffered output data to the socket. */
1424 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1425 len = write(c->sock, buffer_ptr(&c->output),
1426 buffer_len(&c->output));
1428 buffer_clear(&c->output);
1430 buffer_consume(&c->output, len);
1435 channel_handler_init_20(void)
1437 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1438 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1439 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1440 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1441 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1442 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1443 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1444 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1446 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1447 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1448 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1449 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1450 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1451 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1452 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1456 channel_handler_init_13(void)
1458 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1459 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1460 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1461 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1462 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1463 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1464 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1465 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1466 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1468 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1469 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1470 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1471 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1472 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1473 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1474 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1478 channel_handler_init_15(void)
1480 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1481 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1482 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1483 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1484 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1485 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1486 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1488 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1489 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1490 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1491 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1492 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1493 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1497 channel_handler_init(void)
1500 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1501 channel_pre[i] = NULL;
1502 channel_post[i] = NULL;
1505 channel_handler_init_20();
1507 channel_handler_init_13();
1509 channel_handler_init_15();
1512 /* gc dead channels */
1514 channel_garbage_collect(Channel *c)
1518 if (c->detach_user != NULL) {
1519 if (!chan_is_dead(c, 0))
1521 debug("channel %d: gc: notify user", c->self);
1522 c->detach_user(c->self, NULL);
1523 /* if we still have a callback */
1524 if (c->detach_user != NULL)
1526 debug("channel %d: gc: user detached", c->self);
1528 if (!chan_is_dead(c, 1))
1530 debug("channel %d: garbage collecting", c->self);
1535 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1537 static int did_init = 0;
1542 channel_handler_init();
1545 for (i = 0; i < channels_alloc; i++) {
1549 if (ftab[c->type] != NULL)
1550 (*ftab[c->type])(c, readset, writeset);
1551 channel_garbage_collect(c);
1556 * Allocate/update select bitmasks and add any bits relevant to channels in
1560 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1561 int *nallocp, int rekeying)
1566 n = MAX(*maxfdp, channel_max_fd);
1568 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1569 /* perhaps check sz < nalloc/2 and shrink? */
1570 if (*readsetp == NULL || sz > *nallocp) {
1571 *readsetp = xrealloc(*readsetp, sz);
1572 *writesetp = xrealloc(*writesetp, sz);
1576 memset(*readsetp, 0, sz);
1577 memset(*writesetp, 0, sz);
1580 channel_handler(channel_pre, *readsetp, *writesetp);
1584 * After select, perform any appropriate operations for channels which have
1588 channel_after_select(fd_set * readset, fd_set * writeset)
1590 channel_handler(channel_post, readset, writeset);
1594 /* If there is data to send to the connection, enqueue some of it now. */
1597 channel_output_poll(void)
1602 for (i = 0; i < channels_alloc; i++) {
1608 * We are only interested in channels that can have buffered
1612 if (c->type != SSH_CHANNEL_OPEN &&
1613 c->type != SSH_CHANNEL_INPUT_DRAINING)
1616 if (c->type != SSH_CHANNEL_OPEN)
1620 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1621 /* XXX is this true? */
1622 debug3("channel %d: will not send data after close", c->self);
1626 /* Get the amount of buffered data for this channel. */
1627 if ((c->istate == CHAN_INPUT_OPEN ||
1628 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1629 (len = buffer_len(&c->input)) > 0) {
1631 * Send some data for the other side over the secure
1635 if (len > c->remote_window)
1636 len = c->remote_window;
1637 if (len > c->remote_maxpacket)
1638 len = c->remote_maxpacket;
1640 if (packet_is_interactive()) {
1644 /* Keep the packets at reasonable size. */
1645 if (len > packet_get_maxsize()/2)
1646 len = packet_get_maxsize()/2;
1650 packet_start(compat20 ?
1651 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1652 packet_put_int(c->remote_id);
1653 packet_put_string(buffer_ptr(&c->input), len);
1655 buffer_consume(&c->input, len);
1656 c->remote_window -= len;
1658 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1660 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1662 * input-buffer is empty and read-socket shutdown:
1663 * tell peer, that we will not send more data: send IEOF
1667 /* Send extended data, i.e. stderr */
1669 c->remote_window > 0 &&
1670 (len = buffer_len(&c->extended)) > 0 &&
1671 c->extended_usage == CHAN_EXTENDED_READ) {
1672 debug2("channel %d: rwin %d elen %d euse %d",
1673 c->self, c->remote_window, buffer_len(&c->extended),
1675 if (len > c->remote_window)
1676 len = c->remote_window;
1677 if (len > c->remote_maxpacket)
1678 len = c->remote_maxpacket;
1679 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1680 packet_put_int(c->remote_id);
1681 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1682 packet_put_string(buffer_ptr(&c->extended), len);
1684 buffer_consume(&c->extended, len);
1685 c->remote_window -= len;
1686 debug2("channel %d: sent ext data %d", c->self, len);
1692 /* -- protocol input */
1695 channel_input_data(int type, u_int32_t seq, void *ctxt)
1702 /* Get the channel number and verify it. */
1703 id = packet_get_int();
1704 c = channel_lookup(id);
1706 packet_disconnect("Received data for nonexistent channel %d.", id);
1708 /* Ignore any data for non-open channels (might happen on close) */
1709 if (c->type != SSH_CHANNEL_OPEN &&
1710 c->type != SSH_CHANNEL_X11_OPEN)
1713 /* same for protocol 1.5 if output end is no longer open */
1714 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1718 data = packet_get_string(&data_len);
1721 if (data_len > c->local_maxpacket) {
1722 log("channel %d: rcvd big packet %d, maxpack %d",
1723 c->self, data_len, c->local_maxpacket);
1725 if (data_len > c->local_window) {
1726 log("channel %d: rcvd too much data %d, win %d",
1727 c->self, data_len, c->local_window);
1731 c->local_window -= data_len;
1734 buffer_append(&c->output, data, data_len);
1739 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1747 /* Get the channel number and verify it. */
1748 id = packet_get_int();
1749 c = channel_lookup(id);
1752 packet_disconnect("Received extended_data for bad channel %d.", id);
1753 if (c->type != SSH_CHANNEL_OPEN) {
1754 log("channel %d: ext data for non open", id);
1757 tcode = packet_get_int();
1759 c->extended_usage != CHAN_EXTENDED_WRITE ||
1760 tcode != SSH2_EXTENDED_DATA_STDERR) {
1761 log("channel %d: bad ext data", c->self);
1764 data = packet_get_string(&data_len);
1766 if (data_len > c->local_window) {
1767 log("channel %d: rcvd too much extended_data %d, win %d",
1768 c->self, data_len, c->local_window);
1772 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1773 c->local_window -= data_len;
1774 buffer_append(&c->extended, data, data_len);
1779 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1784 id = packet_get_int();
1786 c = channel_lookup(id);
1788 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1791 /* XXX force input close */
1792 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1793 debug("channel %d: FORCE input drain", c->self);
1794 c->istate = CHAN_INPUT_WAIT_DRAIN;
1800 channel_input_close(int type, u_int32_t seq, void *ctxt)
1805 id = packet_get_int();
1807 c = channel_lookup(id);
1809 packet_disconnect("Received close for nonexistent channel %d.", id);
1812 * Send a confirmation that we have closed the channel and no more
1813 * data is coming for it.
1815 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1816 packet_put_int(c->remote_id);
1820 * If the channel is in closed state, we have sent a close request,
1821 * and the other side will eventually respond with a confirmation.
1822 * Thus, we cannot free the channel here, because then there would be
1823 * no-one to receive the confirmation. The channel gets freed when
1824 * the confirmation arrives.
1826 if (c->type != SSH_CHANNEL_CLOSED) {
1828 * Not a closed channel - mark it as draining, which will
1829 * cause it to be freed later.
1831 buffer_clear(&c->input);
1832 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1836 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1838 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
1840 int id = packet_get_int();
1841 Channel *c = channel_lookup(id);
1845 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1846 chan_rcvd_oclose(c);
1850 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
1852 int id = packet_get_int();
1853 Channel *c = channel_lookup(id);
1857 packet_disconnect("Received close confirmation for "
1858 "out-of-range channel %d.", id);
1859 if (c->type != SSH_CHANNEL_CLOSED)
1860 packet_disconnect("Received close confirmation for "
1861 "non-closed channel %d (type %d).", id, c->type);
1866 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
1871 id = packet_get_int();
1872 c = channel_lookup(id);
1874 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1875 packet_disconnect("Received open confirmation for "
1876 "non-opening channel %d.", id);
1877 remote_id = packet_get_int();
1878 /* Record the remote channel number and mark that the channel is now open. */
1879 c->remote_id = remote_id;
1880 c->type = SSH_CHANNEL_OPEN;
1883 c->remote_window = packet_get_int();
1884 c->remote_maxpacket = packet_get_int();
1885 if (c->cb_fn != NULL && c->cb_event == type) {
1886 debug2("callback start");
1887 c->cb_fn(c->self, c->cb_arg);
1888 debug2("callback done");
1890 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1891 c->remote_window, c->remote_maxpacket);
1897 reason2txt(int reason)
1900 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1901 return "administratively prohibited";
1902 case SSH2_OPEN_CONNECT_FAILED:
1903 return "connect failed";
1904 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1905 return "unknown channel type";
1906 case SSH2_OPEN_RESOURCE_SHORTAGE:
1907 return "resource shortage";
1909 return "unknown reason";
1913 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
1916 char *msg = NULL, *lang = NULL;
1919 id = packet_get_int();
1920 c = channel_lookup(id);
1922 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1923 packet_disconnect("Received open failure for "
1924 "non-opening channel %d.", id);
1926 reason = packet_get_int();
1927 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1928 msg = packet_get_string(NULL);
1929 lang = packet_get_string(NULL);
1931 log("channel %d: open failed: %s%s%s", id,
1932 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1939 /* Free the channel. This will also close the socket. */
1944 channel_input_channel_request(int type, u_int32_t seq, void *ctxt)
1949 id = packet_get_int();
1950 c = channel_lookup(id);
1953 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1954 packet_disconnect("Received request for "
1955 "non-open channel %d.", id);
1956 if (c->cb_fn != NULL && c->cb_event == type) {
1957 debug2("callback start");
1958 c->cb_fn(c->self, c->cb_arg);
1959 debug2("callback done");
1961 char *service = packet_get_string(NULL);
1962 debug("channel %d: rcvd request for %s", c->self, service);
1963 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1969 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
1977 /* Get the channel number and verify it. */
1978 id = packet_get_int();
1979 c = channel_lookup(id);
1981 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1982 log("Received window adjust for "
1983 "non-open channel %d.", id);
1986 adjust = packet_get_int();
1988 debug2("channel %d: rcvd adjust %d", id, adjust);
1989 c->remote_window += adjust;
1993 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
1997 char *host, *originator_string;
1998 int remote_id, sock = -1;
2000 remote_id = packet_get_int();
2001 host = packet_get_string(NULL);
2002 host_port = packet_get_int();
2004 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2005 originator_string = packet_get_string(NULL);
2007 originator_string = xstrdup("unknown (remote did not supply name)");
2010 sock = channel_connect_to(host, host_port);
2012 c = channel_new("connected socket",
2013 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2014 originator_string, 1);
2016 error("channel_input_port_open: channel_new failed");
2019 c->remote_id = remote_id;
2023 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2024 packet_put_int(remote_id);
2031 /* -- tcp forwarding */
2034 channel_set_af(int af)
2040 * Initiate forwarding of connections to local port "port" through the secure
2041 * channel to host:port from remote side.
2044 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2045 u_short port_to_connect, int gateway_ports)
2047 return channel_request_forwarding(
2049 host_to_connect, port_to_connect,
2050 gateway_ports, /*remote_fwd*/ 0);
2054 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2055 * (SSH_CHANNEL_RPORT_LISTENER).
2058 channel_request_forwarding(
2059 const char *listen_address, u_short listen_port,
2060 const char *host_to_connect, u_short port_to_connect,
2061 int gateway_ports, int remote_fwd)
2064 int success, sock, on = 1, type;
2065 struct addrinfo hints, *ai, *aitop;
2066 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2068 struct linger linger;
2073 host = listen_address;
2074 type = SSH_CHANNEL_RPORT_LISTENER;
2076 host = host_to_connect;
2077 type = SSH_CHANNEL_PORT_LISTENER;
2080 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2081 error("Forward host name too long.");
2085 /* XXX listen_address is currently ignored */
2087 * getaddrinfo returns a loopback address if the hostname is
2088 * set to NULL and hints.ai_flags is not AI_PASSIVE
2090 memset(&hints, 0, sizeof(hints));
2091 hints.ai_family = IPv4or6;
2092 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2093 hints.ai_socktype = SOCK_STREAM;
2094 snprintf(strport, sizeof strport, "%d", listen_port);
2095 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2096 packet_disconnect("getaddrinfo: fatal error");
2098 for (ai = aitop; ai; ai = ai->ai_next) {
2099 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2101 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2102 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2103 error("channel_request_forwarding: getnameinfo failed");
2106 /* Create a port to listen for the host. */
2107 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2109 /* this is no error since kernel may not support ipv6 */
2110 verbose("socket: %.100s", strerror(errno));
2114 * Set socket options. We would like the socket to disappear
2115 * as soon as it has been closed for whatever reason.
2117 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2119 linger.l_linger = 5;
2120 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2121 debug("Local forwarding listening on %s port %s.", ntop, strport);
2123 /* Bind the socket to the address. */
2124 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2125 /* address can be in use ipv6 address is already bound */
2127 error("bind: %.100s", strerror(errno));
2129 verbose("bind: %.100s", strerror(errno));
2134 /* Start listening for connections on the socket. */
2135 if (listen(sock, 5) < 0) {
2136 error("listen: %.100s", strerror(errno));
2140 /* Allocate a channel number for the socket. */
2141 c = channel_new("port listener", type, sock, sock, -1,
2142 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2143 0, xstrdup("port listener"), 1);
2145 error("channel_request_forwarding: channel_new failed");
2149 strlcpy(c->path, host, sizeof(c->path));
2150 c->host_port = port_to_connect;
2151 c->listening_port = listen_port;
2155 error("channel_request_forwarding: cannot listen to port: %d",
2157 freeaddrinfo(aitop);
2162 * Initiate forwarding of connections to port "port" on remote host through
2163 * the secure channel to host:port from local side.
2167 channel_request_remote_forwarding(u_short listen_port,
2168 const char *host_to_connect, u_short port_to_connect)
2170 int type, success = 0;
2172 /* Record locally that connection to this host/port is permitted. */
2173 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2174 fatal("channel_request_remote_forwarding: too many forwards");
2176 /* Send the forward request to the remote side. */
2178 const char *address_to_bind = "0.0.0.0";
2179 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2180 packet_put_cstring("tcpip-forward");
2181 packet_put_char(0); /* boolean: want reply */
2182 packet_put_cstring(address_to_bind);
2183 packet_put_int(listen_port);
2185 packet_write_wait();
2186 /* Assume that server accepts the request */
2189 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2190 packet_put_int(listen_port);
2191 packet_put_cstring(host_to_connect);
2192 packet_put_int(port_to_connect);
2194 packet_write_wait();
2196 /* Wait for response from the remote side. */
2197 type = packet_read();
2199 case SSH_SMSG_SUCCESS:
2202 case SSH_SMSG_FAILURE:
2203 log("Warning: Server denied remote port forwarding.");
2206 /* Unknown packet */
2207 packet_disconnect("Protocol error for port forward request:"
2208 "received packet type %d.", type);
2212 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2213 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2214 permitted_opens[num_permitted_opens].listen_port = listen_port;
2215 num_permitted_opens++;
2220 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2221 * listening for the port, and sends back a success reply (or disconnect
2222 * message if there was an error). This never returns if there was an error.
2226 channel_input_port_forward_request(int is_root, int gateway_ports)
2228 u_short port, host_port;
2231 /* Get arguments from the packet. */
2232 port = packet_get_int();
2233 hostname = packet_get_string(NULL);
2234 host_port = packet_get_int();
2238 * Check that an unprivileged user is not trying to forward a
2241 if (port < IPPORT_RESERVED && !is_root)
2242 packet_disconnect("Requested forwarding of port %d but user is not root.",
2245 /* Initiate forwarding */
2246 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2248 /* Free the argument string. */
2253 * Permits opening to any host/port if permitted_opens[] is empty. This is
2254 * usually called by the server, because the user could connect to any port
2255 * anyway, and the server has no way to know but to trust the client anyway.
2258 channel_permit_all_opens(void)
2260 if (num_permitted_opens == 0)
2261 all_opens_permitted = 1;
2265 channel_add_permitted_opens(char *host, int port)
2267 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2268 fatal("channel_request_remote_forwarding: too many forwards");
2269 debug("allow port forwarding to host %s port %d", host, port);
2271 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2272 permitted_opens[num_permitted_opens].port_to_connect = port;
2273 num_permitted_opens++;
2275 all_opens_permitted = 0;
2279 channel_clear_permitted_opens(void)
2283 for (i = 0; i < num_permitted_opens; i++)
2284 xfree(permitted_opens[i].host_to_connect);
2285 num_permitted_opens = 0;
2290 /* return socket to remote host, port */
2292 connect_to(const char *host, u_short port)
2294 struct addrinfo hints, *ai, *aitop;
2295 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2299 memset(&hints, 0, sizeof(hints));
2300 hints.ai_family = IPv4or6;
2301 hints.ai_socktype = SOCK_STREAM;
2302 snprintf(strport, sizeof strport, "%d", port);
2303 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2304 error("connect_to %.100s: unknown host (%s)", host,
2305 gai_strerror(gaierr));
2308 for (ai = aitop; ai; ai = ai->ai_next) {
2309 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2311 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2312 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2313 error("connect_to: getnameinfo failed");
2316 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2318 error("socket: %.100s", strerror(errno));
2321 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2322 fatal("connect_to: F_SETFL: %s", strerror(errno));
2323 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2324 errno != EINPROGRESS) {
2325 error("connect_to %.100s port %s: %.100s", ntop, strport,
2328 continue; /* fail -- try next */
2330 break; /* success */
2333 freeaddrinfo(aitop);
2335 error("connect_to %.100s port %d: failed.", host, port);
2343 channel_connect_by_listen_address(u_short listen_port)
2347 for (i = 0; i < num_permitted_opens; i++)
2348 if (permitted_opens[i].listen_port == listen_port)
2350 permitted_opens[i].host_to_connect,
2351 permitted_opens[i].port_to_connect);
2352 error("WARNING: Server requests forwarding for unknown listen_port %d",
2357 /* Check if connecting to that port is permitted and connect. */
2359 channel_connect_to(const char *host, u_short port)
2363 permit = all_opens_permitted;
2365 for (i = 0; i < num_permitted_opens; i++)
2366 if (permitted_opens[i].port_to_connect == port &&
2367 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2372 log("Received request to connect to host %.100s port %d, "
2373 "but the request was denied.", host, port);
2376 return connect_to(host, port);
2379 /* -- X11 forwarding */
2382 * Creates an internet domain socket for listening for X11 connections.
2383 * Returns a suitable display number for the DISPLAY variable, or -1 if
2387 x11_create_display_inet(int x11_display_offset, int gateway_ports,
2388 int single_connection)
2391 int display_number, sock;
2393 struct addrinfo hints, *ai, *aitop;
2394 char strport[NI_MAXSERV];
2395 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2397 for (display_number = x11_display_offset;
2398 display_number < MAX_DISPLAYS;
2400 port = 6000 + display_number;
2401 memset(&hints, 0, sizeof(hints));
2402 hints.ai_family = IPv4or6;
2403 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2404 hints.ai_socktype = SOCK_STREAM;
2405 snprintf(strport, sizeof strport, "%d", port);
2406 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2407 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2410 for (ai = aitop; ai; ai = ai->ai_next) {
2411 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2413 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2415 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2416 error("socket: %.100s", strerror(errno));
2419 debug("x11_create_display_inet: Socket family %d not supported",
2424 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2425 debug("bind port %d: %.100s", port, strerror(errno));
2431 for (n = 0; n < num_socks; n++) {
2437 socks[num_socks++] = sock;
2438 #ifndef DONT_TRY_OTHER_AF
2439 if (num_socks == NUM_SOCKS)
2445 freeaddrinfo(aitop);
2449 if (display_number >= MAX_DISPLAYS) {
2450 error("Failed to allocate internet-domain X11 display socket.");
2453 /* Start listening for connections on the socket. */
2454 for (n = 0; n < num_socks; n++) {
2456 if (listen(sock, 5) < 0) {
2457 error("listen: %.100s", strerror(errno));
2463 /* Allocate a channel for each socket. */
2464 for (n = 0; n < num_socks; n++) {
2466 nc = channel_new("x11 listener",
2467 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2468 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2469 0, xstrdup("X11 inet listener"), 1);
2471 nc->single_connection = single_connection;
2474 /* Return the display number for the DISPLAY environment variable. */
2475 return display_number;
2479 connect_local_xsocket(u_int dnr)
2482 struct sockaddr_un addr;
2484 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2486 error("socket: %.100s", strerror(errno));
2487 memset(&addr, 0, sizeof(addr));
2488 addr.sun_family = AF_UNIX;
2489 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2490 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2493 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2498 x11_connect_display(void)
2500 int display_number, sock = 0, on = 1;
2501 const char *display;
2502 char buf[1024], *cp;
2503 struct addrinfo hints, *ai, *aitop;
2504 char strport[NI_MAXSERV];
2507 /* Try to open a socket for the local X server. */
2508 display = getenv("DISPLAY");
2510 error("DISPLAY not set.");
2514 * Now we decode the value of the DISPLAY variable and make a
2515 * connection to the real X server.
2519 * Check if it is a unix domain socket. Unix domain displays are in
2520 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2522 if (strncmp(display, "unix:", 5) == 0 ||
2523 display[0] == ':') {
2524 /* Connect to the unix domain socket. */
2525 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2526 error("Could not parse display number from DISPLAY: %.100s",
2530 /* Create a socket. */
2531 sock = connect_local_xsocket(display_number);
2535 /* OK, we now have a connection to the display. */
2539 * Connect to an inet socket. The DISPLAY value is supposedly
2540 * hostname:d[.s], where hostname may also be numeric IP address.
2542 strlcpy(buf, display, sizeof(buf));
2543 cp = strchr(buf, ':');
2545 error("Could not find ':' in DISPLAY: %.100s", display);
2549 /* buf now contains the host name. But first we parse the display number. */
2550 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2551 error("Could not parse display number from DISPLAY: %.100s",
2556 /* Look up the host address */
2557 memset(&hints, 0, sizeof(hints));
2558 hints.ai_family = IPv4or6;
2559 hints.ai_socktype = SOCK_STREAM;
2560 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2561 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2562 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2565 for (ai = aitop; ai; ai = ai->ai_next) {
2566 /* Create a socket. */
2567 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2569 debug("socket: %.100s", strerror(errno));
2572 /* Connect it to the display. */
2573 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2574 debug("connect %.100s port %d: %.100s", buf,
2575 6000 + display_number, strerror(errno));
2582 freeaddrinfo(aitop);
2584 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2588 if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &on, sizeof on) == -1)
2589 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
2594 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2595 * the remote channel number. We should do whatever we want, and respond
2596 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2600 x11_input_open(int type, u_int32_t seq, void *ctxt)
2603 int remote_id, sock = 0;
2606 debug("Received X11 open request.");
2608 remote_id = packet_get_int();
2610 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2611 remote_host = packet_get_string(NULL);
2613 remote_host = xstrdup("unknown (remote did not supply name)");
2617 /* Obtain a connection to the real X display. */
2618 sock = x11_connect_display();
2620 /* Allocate a channel for this connection. */
2621 c = channel_new("connected x11 socket",
2622 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2625 error("x11_input_open: channel_new failed");
2628 c->remote_id = remote_id;
2633 /* Send refusal to the remote host. */
2634 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2635 packet_put_int(remote_id);
2637 /* Send a confirmation to the remote host. */
2638 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2639 packet_put_int(remote_id);
2640 packet_put_int(c->self);
2645 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2647 deny_input_open(int type, u_int32_t seq, void *ctxt)
2649 int rchan = packet_get_int();
2651 case SSH_SMSG_AGENT_OPEN:
2652 error("Warning: ssh server tried agent forwarding.");
2654 case SSH_SMSG_X11_OPEN:
2655 error("Warning: ssh server tried X11 forwarding.");
2658 error("deny_input_open: type %d", type);
2661 error("Warning: this is probably a break in attempt by a malicious server.");
2662 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2663 packet_put_int(rchan);
2668 * Requests forwarding of X11 connections, generates fake authentication
2669 * data, and enables authentication spoofing.
2670 * This should be called in the client only.
2673 x11_request_forwarding_with_spoofing(int client_session_id,
2674 const char *proto, const char *data)
2676 u_int data_len = (u_int) strlen(data) / 2;
2677 u_int i, value, len;
2683 cp = getenv("DISPLAY");
2685 cp = strchr(cp, ':');
2687 cp = strchr(cp, '.');
2689 screen_number = atoi(cp + 1);
2693 /* Save protocol name. */
2694 x11_saved_proto = xstrdup(proto);
2697 * Extract real authentication data and generate fake data of the
2700 x11_saved_data = xmalloc(data_len);
2701 x11_fake_data = xmalloc(data_len);
2702 for (i = 0; i < data_len; i++) {
2703 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2704 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2706 rand = arc4random();
2707 x11_saved_data[i] = value;
2708 x11_fake_data[i] = rand & 0xff;
2711 x11_saved_data_len = data_len;
2712 x11_fake_data_len = data_len;
2714 /* Convert the fake data into hex. */
2715 len = 2 * data_len + 1;
2716 new_data = xmalloc(len);
2717 for (i = 0; i < data_len; i++)
2718 snprintf(new_data + 2 * i, len - 2 * i,
2719 "%02x", (u_char) x11_fake_data[i]);
2721 /* Send the request packet. */
2723 channel_request_start(client_session_id, "x11-req", 0);
2724 packet_put_char(0); /* XXX bool single connection */
2726 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2728 packet_put_cstring(proto);
2729 packet_put_cstring(new_data);
2730 packet_put_int(screen_number);
2732 packet_write_wait();
2737 /* -- agent forwarding */
2739 /* Sends a message to the server to request authentication fd forwarding. */
2742 auth_request_forwarding(void)
2744 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2746 packet_write_wait();
2750 * Returns the name of the forwarded authentication socket. Returns NULL if
2751 * there is no forwarded authentication socket. The returned value points to
2756 auth_get_socket_name(void)
2758 return auth_sock_name;
2761 /* removes the agent forwarding socket */
2764 auth_sock_cleanup_proc(void *_pw)
2766 struct passwd *pw = _pw;
2768 if (auth_sock_name) {
2769 temporarily_use_uid(pw);
2770 unlink(auth_sock_name);
2771 rmdir(auth_sock_dir);
2772 auth_sock_name = NULL;
2778 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2779 * This starts forwarding authentication requests.
2783 auth_input_request_forwarding(struct passwd * pw)
2787 struct sockaddr_un sunaddr;
2789 if (auth_get_socket_name() != NULL) {
2790 error("authentication forwarding requested twice.");
2794 /* Temporarily drop privileged uid for mkdir/bind. */
2795 temporarily_use_uid(pw);
2797 /* Allocate a buffer for the socket name, and format the name. */
2798 auth_sock_name = xmalloc(MAXPATHLEN);
2799 auth_sock_dir = xmalloc(MAXPATHLEN);
2800 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2802 /* Create private directory for socket */
2803 if (mkdtemp(auth_sock_dir) == NULL) {
2804 packet_send_debug("Agent forwarding disabled: "
2805 "mkdtemp() failed: %.100s", strerror(errno));
2807 xfree(auth_sock_name);
2808 xfree(auth_sock_dir);
2809 auth_sock_name = NULL;
2810 auth_sock_dir = NULL;
2813 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2814 auth_sock_dir, (int) getpid());
2816 /* delete agent socket on fatal() */
2817 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2819 /* Create the socket. */
2820 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2822 packet_disconnect("socket: %.100s", strerror(errno));
2824 /* Bind it to the name. */
2825 memset(&sunaddr, 0, sizeof(sunaddr));
2826 sunaddr.sun_family = AF_UNIX;
2827 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
2829 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2830 packet_disconnect("bind: %.100s", strerror(errno));
2832 /* Restore the privileged uid. */
2835 /* Start listening on the socket. */
2836 if (listen(sock, 5) < 0)
2837 packet_disconnect("listen: %.100s", strerror(errno));
2839 /* Allocate a channel for the authentication agent socket. */
2840 nc = channel_new("auth socket",
2841 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2842 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2843 0, xstrdup("auth socket"), 1);
2845 error("auth_input_request_forwarding: channel_new failed");
2846 auth_sock_cleanup_proc(pw);
2847 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2851 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2855 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2858 auth_input_open_request(int type, u_int32_t seq, void *ctxt)
2861 int remote_id, sock;
2864 /* Read the remote channel number from the message. */
2865 remote_id = packet_get_int();
2869 * Get a connection to the local authentication agent (this may again
2872 sock = ssh_get_authentication_socket();
2875 * If we could not connect the agent, send an error message back to
2876 * the server. This should never happen unless the agent dies,
2877 * because authentication forwarding is only enabled if we have an
2881 name = xstrdup("authentication agent connection");
2882 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2883 -1, 0, 0, 0, name, 1);
2885 error("auth_input_open_request: channel_new failed");
2889 c->remote_id = remote_id;
2894 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2895 packet_put_int(remote_id);
2897 /* Send a confirmation to the remote host. */
2898 debug("Forwarding authentication connection.");
2899 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2900 packet_put_int(remote_id);
2901 packet_put_int(c->self);