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".
16 * SSH2 support added by Markus Friedl.
17 * Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
18 * Copyright (c) 1999 Dug Song. All rights reserved.
19 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 RCSID("$OpenBSD: channels.c,v 1.103 2001/04/07 08:55:17 markus Exp $");
45 #include <openssl/rsa.h>
46 #include <openssl/dsa.h>
65 /* Maximum number of fake X11 displays to try. */
66 #define MAX_DISPLAYS 1000
68 /* Max len of agent socket */
69 #define MAX_SOCKET_NAME 100
72 * Pointer to an array containing all allocated channels. The array is
73 * dynamically extended as needed.
75 static Channel *channels = NULL;
78 * Size of the channel array. All slots of the array must always be
79 * initialized (at least the type field); unused slots are marked with type
82 static int channels_alloc = 0;
85 * Maximum file descriptor value used in any of the channels. This is
86 * updated in channel_allocate.
88 static int channel_max_fd = 0;
90 /* Name and directory of socket for authentication agent forwarding. */
91 static char *channel_forwarded_auth_socket_name = NULL;
92 static char *channel_forwarded_auth_socket_dir = NULL;
94 /* Saved X11 authentication protocol name. */
95 char *x11_saved_proto = NULL;
97 /* Saved X11 authentication data. This is the real data. */
98 char *x11_saved_data = NULL;
99 u_int x11_saved_data_len = 0;
102 * Fake X11 authentication data. This is what the server will be sending us;
103 * we should replace any occurrences of this by the real data.
105 char *x11_fake_data = NULL;
106 u_int x11_fake_data_len;
109 * Data structure for storing which hosts are permitted for forward requests.
110 * The local sides of any remote forwards are stored in this array to prevent
111 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
112 * network (which might be behind a firewall).
115 char *host_to_connect; /* Connect to 'host'. */
116 u_short port_to_connect; /* Connect to 'port'. */
117 u_short listen_port; /* Remote side should listen port number. */
120 /* List of all permitted host/port pairs to connect. */
121 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
122 /* Number of permitted host/port pairs in the array. */
123 static int num_permitted_opens = 0;
125 * If this is true, all opens are permitted. This is the case on the server
126 * on which we have to trust the client anyway, and the user could do
127 * anything after logging in anyway.
129 static int all_opens_permitted = 0;
131 /* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */
132 static int have_hostname_in_open = 0;
134 /* AF_UNSPEC or AF_INET or AF_INET6 */
137 void port_open_helper(Channel *c, char *rtype);
139 /* Sets specific protocol options. */
142 channel_set_options(int hostname_in_open)
144 have_hostname_in_open = hostname_in_open;
147 /* lookup channel by id */
150 channel_lookup(int id)
153 if (id < 0 || id > channels_alloc) {
154 log("channel_lookup: %d: bad id", id);
158 if (c->type == SSH_CHANNEL_FREE) {
159 log("channel_lookup: %d: bad id: channel free", id);
166 * Register filedescriptors for a channel, used when allocating a channel or
167 * when the channel consumer/producer is ready, e.g. shell exec'd
171 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
172 int extusage, int nonblock)
174 /* Update the maximum file descriptor value. */
175 channel_max_fd = MAX(channel_max_fd, rfd);
176 channel_max_fd = MAX(channel_max_fd, wfd);
177 channel_max_fd = MAX(channel_max_fd, efd);
179 /* XXX set close-on-exec -markus */
183 c->sock = (rfd == wfd) ? rfd : -1;
185 c->extended_usage = extusage;
187 /* XXX ugly hack: nonblock is only set by the server */
188 if (nonblock && isatty(c->rfd)) {
189 debug("channel %d: rfd %d isatty", c->self, c->rfd);
191 if (!isatty(c->wfd)) {
192 error("channel %d: wfd %d is not a tty?",
199 /* enable nonblocking mode */
211 * Allocate a new channel object and set its type and socket. This will cause
212 * remote_name to be freed.
216 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
217 int window, int maxpack, int extusage, char *remote_name, int nonblock)
222 /* Do initial allocation if this is the first call. */
223 if (channels_alloc == 0) {
226 channels = xmalloc(channels_alloc * sizeof(Channel));
227 for (i = 0; i < channels_alloc; i++)
228 channels[i].type = SSH_CHANNEL_FREE;
230 * Kludge: arrange a call to channel_stop_listening if we
231 * terminate with fatal().
233 fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
235 /* Try to find a free slot where to put the new channel. */
236 for (found = -1, i = 0; i < channels_alloc; i++)
237 if (channels[i].type == SSH_CHANNEL_FREE) {
238 /* Found a free slot. */
243 /* There are no free slots. Take last+1 slot and expand the array. */
244 found = channels_alloc;
245 channels_alloc += 10;
246 debug2("channel: expanding %d", channels_alloc);
247 channels = xrealloc(channels, channels_alloc * sizeof(Channel));
248 for (i = found; i < channels_alloc; i++)
249 channels[i].type = SSH_CHANNEL_FREE;
251 /* Initialize and return new channel number. */
252 c = &channels[found];
253 buffer_init(&c->input);
254 buffer_init(&c->output);
255 buffer_init(&c->extended);
256 chan_init_iostates(c);
257 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
261 c->local_window = window;
262 c->local_window_max = window;
263 c->local_consumed = 0;
264 c->local_maxpacket = maxpack;
266 c->remote_name = remote_name;
267 c->remote_window = 0;
268 c->remote_maxpacket = 0;
272 c->dettach_user = NULL;
273 c->input_filter = NULL;
274 debug("channel %d: new [%s]", found, remote_name);
277 /* old interface XXX */
279 channel_allocate(int type, int sock, char *remote_name)
281 return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name, 1);
285 /* Close all channel fd/socket. */
288 channel_close_fds(Channel *c)
308 /* Free the channel and close its fd/socket. */
313 Channel *c = channel_lookup(id);
314 char *s = channel_open_message();
317 packet_disconnect("channel free: bad local channel %d", id);
318 debug("channel_free: channel %d: status: %s", id, s);
321 if (c->dettach_user != NULL) {
322 debug("channel_free: channel %d: dettaching channel user", id);
323 c->dettach_user(c->self, NULL);
326 shutdown(c->sock, SHUT_RDWR);
327 channel_close_fds(c);
328 buffer_free(&c->input);
329 buffer_free(&c->output);
330 buffer_free(&c->extended);
331 c->type = SSH_CHANNEL_FREE;
332 if (c->remote_name) {
333 xfree(c->remote_name);
334 c->remote_name = NULL;
339 * 'channel_pre*' are called just before select() to add any bits relevant to
340 * channels in the select bitmasks.
343 * 'channel_post*': perform any appropriate operations for channels which
344 * have events pending.
346 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
347 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
348 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
351 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
353 FD_SET(c->sock, readset);
357 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
359 debug3("channel %d: waiting for connection", c->self);
360 FD_SET(c->sock, writeset);
364 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
366 if (buffer_len(&c->input) < packet_get_maxsize())
367 FD_SET(c->sock, readset);
368 if (buffer_len(&c->output) > 0)
369 FD_SET(c->sock, writeset);
373 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
375 /* test whether sockets are 'alive' for read/write */
376 if (c->istate == CHAN_INPUT_OPEN)
377 if (buffer_len(&c->input) < packet_get_maxsize())
378 FD_SET(c->sock, readset);
379 if (c->ostate == CHAN_OUTPUT_OPEN ||
380 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
381 if (buffer_len(&c->output) > 0) {
382 FD_SET(c->sock, writeset);
383 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
390 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
392 if (c->istate == CHAN_INPUT_OPEN &&
393 c->remote_window > 0 &&
394 buffer_len(&c->input) < c->remote_window)
395 FD_SET(c->rfd, readset);
396 if (c->ostate == CHAN_OUTPUT_OPEN ||
397 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
398 if (buffer_len(&c->output) > 0) {
399 FD_SET(c->wfd, writeset);
400 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
404 /** XXX check close conditions, too */
406 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
407 buffer_len(&c->extended) > 0)
408 FD_SET(c->efd, writeset);
409 else if (c->extended_usage == CHAN_EXTENDED_READ &&
410 buffer_len(&c->extended) < c->remote_window)
411 FD_SET(c->efd, readset);
416 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
418 if (buffer_len(&c->input) == 0) {
419 packet_start(SSH_MSG_CHANNEL_CLOSE);
420 packet_put_int(c->remote_id);
422 c->type = SSH_CHANNEL_CLOSED;
423 debug("Closing channel %d after input drain.", c->self);
428 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
430 if (buffer_len(&c->output) == 0)
431 channel_free(c->self);
433 FD_SET(c->sock, writeset);
437 * This is a special state for X11 authentication spoofing. An opened X11
438 * connection (when authentication spoofing is being done) remains in this
439 * state until the first packet has been completely read. The authentication
440 * data in that packet is then substituted by the real data if it matches the
441 * fake data, and the channel is put into normal mode.
442 * XXX All this happens at the client side.
445 x11_open_helper(Channel *c)
448 u_int proto_len, data_len;
450 /* Check if the fixed size part of the packet is in buffer. */
451 if (buffer_len(&c->output) < 12)
454 /* Parse the lengths of variable-length fields. */
455 ucp = (u_char *) buffer_ptr(&c->output);
456 if (ucp[0] == 0x42) { /* Byte order MSB first. */
457 proto_len = 256 * ucp[6] + ucp[7];
458 data_len = 256 * ucp[8] + ucp[9];
459 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
460 proto_len = ucp[6] + 256 * ucp[7];
461 data_len = ucp[8] + 256 * ucp[9];
463 debug("Initial X11 packet contains bad byte order byte: 0x%x",
468 /* Check if the whole packet is in buffer. */
469 if (buffer_len(&c->output) <
470 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
473 /* Check if authentication protocol matches. */
474 if (proto_len != strlen(x11_saved_proto) ||
475 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
476 debug("X11 connection uses different authentication protocol.");
479 /* Check if authentication data matches our fake data. */
480 if (data_len != x11_fake_data_len ||
481 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
482 x11_fake_data, x11_fake_data_len) != 0) {
483 debug("X11 auth data does not match fake data.");
486 /* Check fake data length */
487 if (x11_fake_data_len != x11_saved_data_len) {
488 error("X11 fake_data_len %d != saved_data_len %d",
489 x11_fake_data_len, x11_saved_data_len);
493 * Received authentication protocol and data match
494 * our fake data. Substitute the fake data with real
497 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
498 x11_saved_data, x11_saved_data_len);
503 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
505 int ret = x11_open_helper(c);
507 /* Start normal processing for the channel. */
508 c->type = SSH_CHANNEL_OPEN;
509 channel_pre_open_13(c, readset, writeset);
510 } else if (ret == -1) {
512 * We have received an X11 connection that has bad
513 * authentication information.
515 log("X11 connection rejected because of wrong authentication.");
516 buffer_clear(&c->input);
517 buffer_clear(&c->output);
520 c->type = SSH_CHANNEL_CLOSED;
521 packet_start(SSH_MSG_CHANNEL_CLOSE);
522 packet_put_int(c->remote_id);
528 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
530 int ret = x11_open_helper(c);
532 c->type = SSH_CHANNEL_OPEN;
534 channel_pre_open_20(c, readset, writeset);
536 channel_pre_open_15(c, readset, writeset);
537 } else if (ret == -1) {
538 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
539 chan_read_failed(c); /** force close? */
540 chan_write_failed(c);
541 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
545 #define SSH_SOCKS_HEAD 1+1+2+4
548 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
551 int len, i, done, have;
557 struct in_addr dest_ip;
560 have = buffer_len(&c->input);
562 debug("channel %d: pre_dynamic have: %d", c->self, have);
563 /*buffer_dump(&c->input);*/
565 /* Check if the fixed size part of the packet is in buffer. */
566 if (have < SSH_SOCKS_HEAD + 1) {
568 FD_SET(c->sock, readset);
571 /* Check for end of username */
572 p = buffer_ptr(&c->input);
574 for (i = SSH_SOCKS_HEAD; i < have; i++) {
582 FD_SET(c->sock, readset);
585 buffer_get(&c->input, (char *)&s4_req.version, 1);
586 buffer_get(&c->input, (char *)&s4_req.command, 1);
587 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
588 buffer_get(&c->input, (char *)&s4_req.dest_ip, 4);
589 p = buffer_ptr(&c->input);
591 have = buffer_len(&c->input);
592 debug2("channel %d: pre_dynamic user: %s/%d", c->self, p, len);
594 fatal("channel %d: pre_dynamic: len %d > have %d",
596 strlcpy(username, p, sizeof(username));
597 buffer_consume(&c->input, len);
598 buffer_consume(&c->input, 1); /* trailing '\0' */
600 host = inet_ntoa(s4_req.dest_ip);
601 strlcpy(c->path, host, sizeof(c->path));
602 c->host_port = ntohs(s4_req.dest_port);
604 debug("channel %d: dynamic request received: "
605 "socks%x://%s@%s:%u/command?%u",
606 c->self, s4_req.version, username, host, c->host_port,
609 if ((s4_req.version != 4) || (s4_req.command != 1)) {
610 debug("channel %d: cannot handle: socks VN %d CN %d",
611 c->self, s4_req.version, s4_req.command);
612 channel_free(c->self);
616 s4_rsp.version = 0; /* VN: version of reply code */
617 s4_rsp.command = 90; /* CD: request granted */
618 s4_rsp.dest_port = 0; /* ignored */
619 s4_rsp.dest_ip.s_addr = INADDR_ANY; /* ignored */
620 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
622 /* switch to next state */
623 c->type = SSH_CHANNEL_OPENING;
624 port_open_helper(c, "direct-tcpip");
628 /* This is our fake X11 server socket. */
630 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
632 struct sockaddr addr;
635 char buf[16384], *remote_ipaddr;
638 if (FD_ISSET(c->sock, readset)) {
639 debug("X11 connection requested.");
640 addrlen = sizeof(addr);
641 newsock = accept(c->sock, &addr, &addrlen);
643 error("accept: %.100s", strerror(errno));
646 remote_ipaddr = get_peer_ipaddr(newsock);
647 remote_port = get_peer_port(newsock);
648 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
649 remote_ipaddr, remote_port);
651 newch = channel_new("x11",
652 SSH_CHANNEL_OPENING, newsock, newsock, -1,
653 c->local_window_max, c->local_maxpacket,
656 packet_start(SSH2_MSG_CHANNEL_OPEN);
657 packet_put_cstring("x11");
658 packet_put_int(newch);
659 packet_put_int(c->local_window_max);
660 packet_put_int(c->local_maxpacket);
661 /* originator ipaddr and port */
662 packet_put_cstring(remote_ipaddr);
663 if (datafellows & SSH_BUG_X11FWD) {
664 debug("ssh2 x11 bug compat mode");
666 packet_put_int(remote_port);
670 packet_start(SSH_SMSG_X11_OPEN);
671 packet_put_int(newch);
672 if (have_hostname_in_open)
673 packet_put_string(buf, strlen(buf));
676 xfree(remote_ipaddr);
681 port_open_helper(Channel *c, char *rtype)
685 char *remote_ipaddr = get_peer_ipaddr(c->sock);
686 u_short remote_port = get_peer_port(c->sock);
688 direct = (strcmp(rtype, "direct-tcpip") == 0);
690 snprintf(buf, sizeof buf,
691 "%s: listening port %d for %.100s port %d, "
692 "connect from %.200s port %d",
693 rtype, c->listening_port, c->path, c->host_port,
694 remote_ipaddr, remote_port);
696 xfree(c->remote_name);
697 c->remote_name = xstrdup(buf);
700 packet_start(SSH2_MSG_CHANNEL_OPEN);
701 packet_put_cstring(rtype);
702 packet_put_int(c->self);
703 packet_put_int(c->local_window_max);
704 packet_put_int(c->local_maxpacket);
706 /* target host, port */
707 packet_put_cstring(c->path);
708 packet_put_int(c->host_port);
710 /* listen address, port */
711 packet_put_cstring(c->path);
712 packet_put_int(c->listening_port);
714 /* originator host and port */
715 packet_put_cstring(remote_ipaddr);
716 packet_put_int(remote_port);
719 packet_start(SSH_MSG_PORT_OPEN);
720 packet_put_int(c->self);
721 packet_put_cstring(c->path);
722 packet_put_int(c->host_port);
723 if (have_hostname_in_open)
724 packet_put_cstring(c->remote_name);
727 xfree(remote_ipaddr);
731 * This socket is listening for connections to a forwarded TCP/IP port.
734 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
737 struct sockaddr addr;
738 int newsock, newch, nextstate;
742 if (FD_ISSET(c->sock, readset)) {
743 debug("Connection to port %d forwarding "
744 "to %.100s port %d requested.",
745 c->listening_port, c->path, c->host_port);
747 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
748 "forwarded-tcpip" : "direct-tcpip";
749 nextstate = (c->host_port == 0) ? SSH_CHANNEL_DYNAMIC :
752 addrlen = sizeof(addr);
753 newsock = accept(c->sock, &addr, &addrlen);
755 error("accept: %.100s", strerror(errno));
758 newch = channel_new(rtype,
759 nextstate, newsock, newsock, -1,
760 c->local_window_max, c->local_maxpacket,
761 0, xstrdup(rtype), 1);
763 nc = channel_lookup(newch);
765 error("xxx: no new channel:");
768 nc->listening_port = c->listening_port;
769 nc->host_port = c->host_port;
770 strlcpy(nc->path, c->path, sizeof(nc->path));
772 if (nextstate != SSH_CHANNEL_DYNAMIC)
773 port_open_helper(nc, rtype);
778 * This is the authentication agent socket listening for connections from
782 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
784 struct sockaddr addr;
788 if (FD_ISSET(c->sock, readset)) {
789 addrlen = sizeof(addr);
790 newsock = accept(c->sock, &addr, &addrlen);
792 error("accept from auth socket: %.100s", strerror(errno));
795 newch = channel_new("accepted auth socket",
796 SSH_CHANNEL_OPENING, newsock, newsock, -1,
797 c->local_window_max, c->local_maxpacket,
798 0, xstrdup("accepted auth socket"), 1);
800 packet_start(SSH2_MSG_CHANNEL_OPEN);
801 packet_put_cstring("auth-agent@openssh.com");
802 packet_put_int(newch);
803 packet_put_int(c->local_window_max);
804 packet_put_int(c->local_maxpacket);
806 packet_start(SSH_SMSG_AGENT_OPEN);
807 packet_put_int(newch);
814 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
816 if (FD_ISSET(c->sock, writeset)) {
818 int sz = sizeof(err);
819 c->type = SSH_CHANNEL_OPEN;
820 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err, &sz) < 0) {
821 debug("getsockopt SO_ERROR failed");
824 debug("channel %d: connected)", c->self);
826 debug("channel %d: not connected: %s",
827 c->self, strerror(err));
829 chan_write_failed(c);
836 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
842 FD_ISSET(c->rfd, readset)) {
843 len = read(c->rfd, buf, sizeof(buf));
844 if (len < 0 && (errno == EINTR || errno == EAGAIN))
847 debug("channel %d: read<=0 rfd %d len %d",
848 c->self, c->rfd, len);
849 if (c->type == SSH_CHANNEL_DYNAMIC) {
851 * we are not yet connected to a remote peer,
852 * so the connection-close protocol won't work
854 debug("channel %d: dynamic: closed", c->self);
855 channel_free(c->self);
859 buffer_consume(&c->output, buffer_len(&c->output));
860 c->type = SSH_CHANNEL_INPUT_DRAINING;
861 debug("Channel %d status set to input draining.", c->self);
867 if(c->input_filter != NULL) {
868 if (c->input_filter(c, buf, len) == -1) {
869 debug("filter stops channel %d", c->self);
873 buffer_append(&c->input, buf, len);
879 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
884 /* Send buffered output data to the socket. */
886 FD_ISSET(c->wfd, writeset) &&
887 buffer_len(&c->output) > 0) {
888 len = write(c->wfd, buffer_ptr(&c->output),
889 buffer_len(&c->output));
890 if (len < 0 && (errno == EINTR || errno == EAGAIN))
894 buffer_consume(&c->output, buffer_len(&c->output));
895 debug("Channel %d status set to input draining.", c->self);
896 c->type = SSH_CHANNEL_INPUT_DRAINING;
898 chan_write_failed(c);
902 if (compat20 && c->isatty) {
903 if (tcgetattr(c->wfd, &tio) == 0 &&
904 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
906 * Simulate echo to reduce the impact of
907 * traffic analysis. We need to match the
908 * size of a SSH2_MSG_CHANNEL_DATA message
909 * (4 byte channel id + data)
911 packet_send_ignore(4 + len);
915 buffer_consume(&c->output, len);
916 if (compat20 && len > 0) {
917 c->local_consumed += len;
923 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
928 /** XXX handle drain efd, too */
930 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
931 FD_ISSET(c->efd, writeset) &&
932 buffer_len(&c->extended) > 0) {
933 len = write(c->efd, buffer_ptr(&c->extended),
934 buffer_len(&c->extended));
935 debug2("channel %d: written %d to efd %d",
936 c->self, len, c->efd);
937 if (len < 0 && (errno == EINTR || errno == EAGAIN))
940 debug2("channel %d: closing write-efd %d",
945 buffer_consume(&c->extended, len);
946 c->local_consumed += len;
948 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
949 FD_ISSET(c->efd, readset)) {
950 len = read(c->efd, buf, sizeof(buf));
951 debug2("channel %d: read %d from efd %d",
952 c->self, len, c->efd);
953 if (len < 0 && (errno == EINTR || errno == EAGAIN))
956 debug2("channel %d: closing read-efd %d",
961 buffer_append(&c->extended, buf, len);
968 channel_check_window(Channel *c)
970 if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
971 c->local_window < c->local_window_max/2 &&
972 c->local_consumed > 0) {
973 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
974 packet_put_int(c->remote_id);
975 packet_put_int(c->local_consumed);
977 debug2("channel %d: window %d sent adjust %d",
978 c->self, c->local_window,
980 c->local_window += c->local_consumed;
981 c->local_consumed = 0;
987 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
989 channel_handle_rfd(c, readset, writeset);
990 channel_handle_wfd(c, readset, writeset);
994 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
996 channel_handle_rfd(c, readset, writeset);
997 channel_handle_wfd(c, readset, writeset);
998 channel_handle_efd(c, readset, writeset);
1000 channel_check_window(c);
1004 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1007 /* Send buffered output data to the socket. */
1008 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1009 len = write(c->sock, buffer_ptr(&c->output),
1010 buffer_len(&c->output));
1012 buffer_consume(&c->output, buffer_len(&c->output));
1014 buffer_consume(&c->output, len);
1019 channel_post_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1021 channel_handle_rfd(c, readset, writeset);
1025 channel_handler_init_20(void)
1027 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1028 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1029 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1030 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1031 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1032 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1033 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1034 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1036 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1037 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1038 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1039 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1040 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1041 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1042 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_dynamic;
1046 channel_handler_init_13(void)
1048 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1049 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1050 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1051 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1052 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1053 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1054 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1055 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1056 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1058 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1059 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1060 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1061 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1062 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1063 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1064 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_dynamic;
1068 channel_handler_init_15(void)
1070 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1071 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1072 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1073 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1074 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1075 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1076 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1078 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1079 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1080 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1081 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1082 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1083 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_dynamic;
1087 channel_handler_init(void)
1090 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1091 channel_pre[i] = NULL;
1092 channel_post[i] = NULL;
1095 channel_handler_init_20();
1097 channel_handler_init_13();
1099 channel_handler_init_15();
1103 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1105 static int did_init = 0;
1110 channel_handler_init();
1113 for (i = 0; i < channels_alloc; i++) {
1115 if (c->type == SSH_CHANNEL_FREE)
1117 if (ftab[c->type] == NULL)
1119 (*ftab[c->type])(c, readset, writeset);
1120 if (chan_is_dead(c)) {
1122 * we have to remove the fd's from the select mask
1123 * before the channels are free'd and the fd's are
1127 FD_CLR(c->wfd, writeset);
1129 FD_CLR(c->rfd, readset);
1131 if (c->extended_usage == CHAN_EXTENDED_READ)
1132 FD_CLR(c->efd, readset);
1133 if (c->extended_usage == CHAN_EXTENDED_WRITE)
1134 FD_CLR(c->efd, writeset);
1136 channel_free(c->self);
1142 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1148 n = MAX(*maxfdp, channel_max_fd);
1150 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1151 if (*readsetp == NULL || n > *maxfdp) {
1156 *readsetp = xmalloc(sz);
1157 *writesetp = xmalloc(sz);
1160 memset(*readsetp, 0, sz);
1161 memset(*writesetp, 0, sz);
1164 channel_handler(channel_pre, *readsetp, *writesetp);
1168 channel_after_select(fd_set * readset, fd_set * writeset)
1170 channel_handler(channel_post, readset, writeset);
1173 /* If there is data to send to the connection, enqueue some of it now. */
1176 channel_output_poll()
1181 for (i = 0; i < channels_alloc; i++) {
1184 /* We are only interested in channels that can have buffered incoming data. */
1186 if (c->type != SSH_CHANNEL_OPEN &&
1187 c->type != SSH_CHANNEL_INPUT_DRAINING)
1190 if (c->type != SSH_CHANNEL_OPEN)
1194 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1195 /* XXX is this true? */
1196 debug2("channel %d: no data after CLOSE", c->self);
1200 /* Get the amount of buffered data for this channel. */
1201 if ((c->istate == CHAN_INPUT_OPEN ||
1202 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1203 (len = buffer_len(&c->input)) > 0) {
1204 /* Send some data for the other side over the secure connection. */
1206 if (len > c->remote_window)
1207 len = c->remote_window;
1208 if (len > c->remote_maxpacket)
1209 len = c->remote_maxpacket;
1211 if (packet_is_interactive()) {
1215 /* Keep the packets at reasonable size. */
1216 if (len > packet_get_maxsize()/2)
1217 len = packet_get_maxsize()/2;
1221 packet_start(compat20 ?
1222 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1223 packet_put_int(c->remote_id);
1224 packet_put_string(buffer_ptr(&c->input), len);
1226 buffer_consume(&c->input, len);
1227 c->remote_window -= len;
1229 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1231 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1233 * input-buffer is empty and read-socket shutdown:
1234 * tell peer, that we will not send more data: send IEOF
1238 /* Send extended data, i.e. stderr */
1240 c->remote_window > 0 &&
1241 (len = buffer_len(&c->extended)) > 0 &&
1242 c->extended_usage == CHAN_EXTENDED_READ) {
1243 debug2("channel %d: rwin %d elen %d euse %d",
1244 c->self, c->remote_window, buffer_len(&c->extended),
1246 if (len > c->remote_window)
1247 len = c->remote_window;
1248 if (len > c->remote_maxpacket)
1249 len = c->remote_maxpacket;
1250 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1251 packet_put_int(c->remote_id);
1252 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1253 packet_put_string(buffer_ptr(&c->extended), len);
1255 buffer_consume(&c->extended, len);
1256 c->remote_window -= len;
1257 debug2("channel %d: sent ext data %d", c->self, len);
1263 * This is called when a packet of type CHANNEL_DATA has just been received.
1264 * The message type has already been consumed, but channel number and data is
1269 channel_input_data(int type, int plen, void *ctxt)
1276 /* Get the channel number and verify it. */
1277 id = packet_get_int();
1278 c = channel_lookup(id);
1280 packet_disconnect("Received data for nonexistent channel %d.", id);
1282 /* Ignore any data for non-open channels (might happen on close) */
1283 if (c->type != SSH_CHANNEL_OPEN &&
1284 c->type != SSH_CHANNEL_X11_OPEN)
1287 /* same for protocol 1.5 if output end is no longer open */
1288 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1292 data = packet_get_string(&data_len);
1296 if (data_len > c->local_maxpacket) {
1297 log("channel %d: rcvd big packet %d, maxpack %d",
1298 c->self, data_len, c->local_maxpacket);
1300 if (data_len > c->local_window) {
1301 log("channel %d: rcvd too much data %d, win %d",
1302 c->self, data_len, c->local_window);
1306 c->local_window -= data_len;
1308 packet_integrity_check(plen, 4 + 4 + data_len, type);
1310 buffer_append(&c->output, data, data_len);
1314 channel_input_extended_data(int type, int plen, void *ctxt)
1322 /* Get the channel number and verify it. */
1323 id = packet_get_int();
1324 c = channel_lookup(id);
1327 packet_disconnect("Received extended_data for bad channel %d.", id);
1328 if (c->type != SSH_CHANNEL_OPEN) {
1329 log("channel %d: ext data for non open", id);
1332 tcode = packet_get_int();
1334 c->extended_usage != CHAN_EXTENDED_WRITE ||
1335 tcode != SSH2_EXTENDED_DATA_STDERR) {
1336 log("channel %d: bad ext data", c->self);
1339 data = packet_get_string(&data_len);
1341 if (data_len > c->local_window) {
1342 log("channel %d: rcvd too much extended_data %d, win %d",
1343 c->self, data_len, c->local_window);
1347 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1348 c->local_window -= data_len;
1349 buffer_append(&c->extended, data, data_len);
1355 * Returns true if no channel has too much buffered data, and false if one or
1356 * more channel is overfull.
1360 channel_not_very_much_buffered_data()
1365 for (i = 0; i < channels_alloc; i++) {
1367 if (c->type == SSH_CHANNEL_OPEN) {
1368 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
1369 debug("channel %d: big input buffer %d",
1370 c->self, buffer_len(&c->input));
1373 if (buffer_len(&c->output) > packet_get_maxsize()) {
1374 debug("channel %d: big output buffer %d",
1375 c->self, buffer_len(&c->output));
1384 channel_input_ieof(int type, int plen, void *ctxt)
1389 packet_integrity_check(plen, 4, type);
1391 id = packet_get_int();
1392 c = channel_lookup(id);
1394 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1399 channel_input_close(int type, int plen, void *ctxt)
1404 packet_integrity_check(plen, 4, type);
1406 id = packet_get_int();
1407 c = channel_lookup(id);
1409 packet_disconnect("Received close for nonexistent channel %d.", id);
1412 * Send a confirmation that we have closed the channel and no more
1413 * data is coming for it.
1415 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1416 packet_put_int(c->remote_id);
1420 * If the channel is in closed state, we have sent a close request,
1421 * and the other side will eventually respond with a confirmation.
1422 * Thus, we cannot free the channel here, because then there would be
1423 * no-one to receive the confirmation. The channel gets freed when
1424 * the confirmation arrives.
1426 if (c->type != SSH_CHANNEL_CLOSED) {
1428 * Not a closed channel - mark it as draining, which will
1429 * cause it to be freed later.
1431 buffer_consume(&c->input, buffer_len(&c->input));
1432 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1436 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1438 channel_input_oclose(int type, int plen, void *ctxt)
1440 int id = packet_get_int();
1441 Channel *c = channel_lookup(id);
1442 packet_integrity_check(plen, 4, type);
1444 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1445 chan_rcvd_oclose(c);
1449 channel_input_close_confirmation(int type, int plen, void *ctxt)
1451 int id = packet_get_int();
1452 Channel *c = channel_lookup(id);
1456 packet_disconnect("Received close confirmation for "
1457 "out-of-range channel %d.", id);
1458 if (c->type != SSH_CHANNEL_CLOSED)
1459 packet_disconnect("Received close confirmation for "
1460 "non-closed channel %d (type %d).", id, c->type);
1461 channel_free(c->self);
1465 channel_input_open_confirmation(int type, int plen, void *ctxt)
1471 packet_integrity_check(plen, 4 + 4, type);
1473 id = packet_get_int();
1474 c = channel_lookup(id);
1476 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1477 packet_disconnect("Received open confirmation for "
1478 "non-opening channel %d.", id);
1479 remote_id = packet_get_int();
1480 /* Record the remote channel number and mark that the channel is now open. */
1481 c->remote_id = remote_id;
1482 c->type = SSH_CHANNEL_OPEN;
1485 c->remote_window = packet_get_int();
1486 c->remote_maxpacket = packet_get_int();
1488 if (c->cb_fn != NULL && c->cb_event == type) {
1489 debug2("callback start");
1490 c->cb_fn(c->self, c->cb_arg);
1491 debug2("callback done");
1493 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1494 c->remote_window, c->remote_maxpacket);
1499 channel_input_open_failure(int type, int plen, void *ctxt)
1502 char *msg = NULL, *lang = NULL;
1506 packet_integrity_check(plen, 4, type);
1508 id = packet_get_int();
1509 c = channel_lookup(id);
1511 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1512 packet_disconnect("Received open failure for "
1513 "non-opening channel %d.", id);
1515 reason = packet_get_int();
1516 if (packet_remaining() > 0) {
1517 msg = packet_get_string(NULL);
1518 lang = packet_get_string(NULL);
1521 log("channel_open_failure: %d: reason %d %s", id,
1522 reason, msg ? msg : "<no additional info>");
1528 /* Free the channel. This will also close the socket. */
1533 channel_input_channel_request(int type, int plen, void *ctxt)
1538 id = packet_get_int();
1539 c = channel_lookup(id);
1542 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1543 packet_disconnect("Received request for "
1544 "non-open channel %d.", id);
1545 if (c->cb_fn != NULL && c->cb_event == type) {
1546 debug2("callback start");
1547 c->cb_fn(c->self, c->cb_arg);
1548 debug2("callback done");
1550 char *service = packet_get_string(NULL);
1551 debug("channel %d: rcvd request for %s", c->self, service);
1552 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1558 channel_input_window_adjust(int type, int plen, void *ctxt)
1566 /* Get the channel number and verify it. */
1567 id = packet_get_int();
1568 c = channel_lookup(id);
1570 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1571 log("Received window adjust for "
1572 "non-open channel %d.", id);
1575 adjust = packet_get_int();
1577 debug2("channel %d: rcvd adjust %d", id, adjust);
1578 c->remote_window += adjust;
1582 * Stops listening for channels, and removes any unix domain sockets that we
1587 channel_stop_listening()
1590 for (i = 0; i < channels_alloc; i++) {
1591 switch (channels[i].type) {
1592 case SSH_CHANNEL_AUTH_SOCKET:
1593 close(channels[i].sock);
1594 unlink(channels[i].path);
1597 case SSH_CHANNEL_PORT_LISTENER:
1598 case SSH_CHANNEL_RPORT_LISTENER:
1599 case SSH_CHANNEL_X11_LISTENER:
1600 close(channels[i].sock);
1610 * Closes the sockets/fds of all channels. This is used to close extra file
1611 * descriptors after a fork.
1618 for (i = 0; i < channels_alloc; i++)
1619 if (channels[i].type != SSH_CHANNEL_FREE)
1620 channel_close_fds(&channels[i]);
1623 /* Returns true if any channel is still open. */
1626 channel_still_open()
1629 for (i = 0; i < channels_alloc; i++)
1630 switch (channels[i].type) {
1631 case SSH_CHANNEL_FREE:
1632 case SSH_CHANNEL_X11_LISTENER:
1633 case SSH_CHANNEL_PORT_LISTENER:
1634 case SSH_CHANNEL_RPORT_LISTENER:
1635 case SSH_CHANNEL_CLOSED:
1636 case SSH_CHANNEL_AUTH_SOCKET:
1637 case SSH_CHANNEL_DYNAMIC:
1638 case SSH_CHANNEL_CONNECTING: /* XXX ??? */
1640 case SSH_CHANNEL_LARVAL:
1642 fatal("cannot happen: SSH_CHANNEL_LARVAL");
1644 case SSH_CHANNEL_OPENING:
1645 case SSH_CHANNEL_OPEN:
1646 case SSH_CHANNEL_X11_OPEN:
1648 case SSH_CHANNEL_INPUT_DRAINING:
1649 case SSH_CHANNEL_OUTPUT_DRAINING:
1651 fatal("cannot happen: OUT_DRAIN");
1654 fatal("channel_still_open: bad channel type %d", channels[i].type);
1661 * Returns a message describing the currently open forwarded connections,
1662 * suitable for sending to the client. The message contains crlf pairs for
1667 channel_open_message()
1673 buffer_init(&buffer);
1674 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
1675 buffer_append(&buffer, buf, strlen(buf));
1676 for (i = 0; i < channels_alloc; i++) {
1677 Channel *c = &channels[i];
1679 case SSH_CHANNEL_FREE:
1680 case SSH_CHANNEL_X11_LISTENER:
1681 case SSH_CHANNEL_PORT_LISTENER:
1682 case SSH_CHANNEL_RPORT_LISTENER:
1683 case SSH_CHANNEL_CLOSED:
1684 case SSH_CHANNEL_AUTH_SOCKET:
1686 case SSH_CHANNEL_LARVAL:
1687 case SSH_CHANNEL_OPENING:
1688 case SSH_CHANNEL_CONNECTING:
1689 case SSH_CHANNEL_DYNAMIC:
1690 case SSH_CHANNEL_OPEN:
1691 case SSH_CHANNEL_X11_OPEN:
1692 case SSH_CHANNEL_INPUT_DRAINING:
1693 case SSH_CHANNEL_OUTPUT_DRAINING:
1694 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
1695 c->self, c->remote_name,
1696 c->type, c->remote_id,
1697 c->istate, buffer_len(&c->input),
1698 c->ostate, buffer_len(&c->output),
1700 buffer_append(&buffer, buf, strlen(buf));
1703 fatal("channel_open_message: bad channel type %d", c->type);
1707 buffer_append(&buffer, "\0", 1);
1708 cp = xstrdup(buffer_ptr(&buffer));
1709 buffer_free(&buffer);
1714 * Initiate forwarding of connections to local port "port" through the secure
1715 * channel to host:port from remote side.
1718 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
1719 u_short port_to_connect, int gateway_ports)
1721 return channel_request_forwarding(
1723 host_to_connect, port_to_connect,
1724 gateway_ports, /*remote_fwd*/ 0);
1728 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
1729 * (SSH_CHANNEL_RPORT_LISTENER).
1732 channel_request_forwarding(
1733 const char *listen_address, u_short listen_port,
1734 const char *host_to_connect, u_short port_to_connect,
1735 int gateway_ports, int remote_fwd)
1737 int success, ch, sock, on = 1, ctype;
1738 struct addrinfo hints, *ai, *aitop;
1739 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1741 struct linger linger;
1746 host = listen_address;
1747 ctype = SSH_CHANNEL_RPORT_LISTENER;
1749 host = host_to_connect;
1750 ctype =SSH_CHANNEL_PORT_LISTENER;
1753 if (strlen(host) > sizeof(channels[0].path) - 1) {
1754 error("Forward host name too long.");
1758 /* XXX listen_address is currently ignored */
1760 * getaddrinfo returns a loopback address if the hostname is
1761 * set to NULL and hints.ai_flags is not AI_PASSIVE
1763 memset(&hints, 0, sizeof(hints));
1764 hints.ai_family = IPv4or6;
1765 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
1766 hints.ai_socktype = SOCK_STREAM;
1767 snprintf(strport, sizeof strport, "%d", listen_port);
1768 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
1769 packet_disconnect("getaddrinfo: fatal error");
1771 for (ai = aitop; ai; ai = ai->ai_next) {
1772 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1774 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1775 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1776 error("channel_request_forwarding: getnameinfo failed");
1779 /* Create a port to listen for the host. */
1780 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1782 /* this is no error since kernel may not support ipv6 */
1783 verbose("socket: %.100s", strerror(errno));
1787 * Set socket options. We would like the socket to disappear
1788 * as soon as it has been closed for whatever reason.
1790 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
1792 linger.l_linger = 5;
1793 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
1794 debug("Local forwarding listening on %s port %s.", ntop, strport);
1796 /* Bind the socket to the address. */
1797 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1798 /* address can be in use ipv6 address is already bound */
1800 error("bind: %.100s", strerror(errno));
1802 verbose("bind: %.100s", strerror(errno));
1807 /* Start listening for connections on the socket. */
1808 if (listen(sock, 5) < 0) {
1809 error("listen: %.100s", strerror(errno));
1813 /* Allocate a channel number for the socket. */
1814 ch = channel_new("port listener", ctype, sock, sock, -1,
1815 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1816 0, xstrdup("port listener"), 1);
1817 strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
1818 channels[ch].host_port = port_to_connect;
1819 channels[ch].listening_port = listen_port;
1823 error("channel_request_forwarding: cannot listen to port: %d",
1825 freeaddrinfo(aitop);
1830 * Initiate forwarding of connections to port "port" on remote host through
1831 * the secure channel to host:port from local side.
1835 channel_request_remote_forwarding(u_short listen_port,
1836 const char *host_to_connect, u_short port_to_connect)
1838 int payload_len, type, success = 0;
1840 /* Record locally that connection to this host/port is permitted. */
1841 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
1842 fatal("channel_request_remote_forwarding: too many forwards");
1844 /* Send the forward request to the remote side. */
1846 const char *address_to_bind = "0.0.0.0";
1847 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1848 packet_put_cstring("tcpip-forward");
1849 packet_put_char(0); /* boolean: want reply */
1850 packet_put_cstring(address_to_bind);
1851 packet_put_int(listen_port);
1853 packet_write_wait();
1854 /* Assume that server accepts the request */
1857 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
1858 packet_put_int(listen_port);
1859 packet_put_cstring(host_to_connect);
1860 packet_put_int(port_to_connect);
1862 packet_write_wait();
1864 /* Wait for response from the remote side. */
1865 type = packet_read(&payload_len);
1867 case SSH_SMSG_SUCCESS:
1870 case SSH_SMSG_FAILURE:
1871 log("Warning: Server denied remote port forwarding.");
1874 /* Unknown packet */
1875 packet_disconnect("Protocol error for port forward request:"
1876 "received packet type %d.", type);
1880 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
1881 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
1882 permitted_opens[num_permitted_opens].listen_port = listen_port;
1883 num_permitted_opens++;
1888 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
1889 * listening for the port, and sends back a success reply (or disconnect
1890 * message if there was an error). This never returns if there was an error.
1894 channel_input_port_forward_request(int is_root, int gateway_ports)
1896 u_short port, host_port;
1899 /* Get arguments from the packet. */
1900 port = packet_get_int();
1901 hostname = packet_get_string(NULL);
1902 host_port = packet_get_int();
1906 * Check that an unprivileged user is not trying to forward a
1909 if (port < IPPORT_RESERVED && !is_root)
1910 packet_disconnect("Requested forwarding of port %d but user is not root.",
1913 /* Initiate forwarding */
1914 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
1916 /* Free the argument string. */
1921 * Permits opening to any host/port if permitted_opens[] is empty. This is
1922 * usually called by the server, because the user could connect to any port
1923 * anyway, and the server has no way to know but to trust the client anyway.
1926 channel_permit_all_opens()
1928 if (num_permitted_opens == 0)
1929 all_opens_permitted = 1;
1933 channel_add_permitted_opens(char *host, int port)
1935 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
1936 fatal("channel_request_remote_forwarding: too many forwards");
1937 debug("allow port forwarding to host %s port %d", host, port);
1939 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
1940 permitted_opens[num_permitted_opens].port_to_connect = port;
1941 num_permitted_opens++;
1943 all_opens_permitted = 0;
1947 channel_clear_permitted_opens(void)
1951 for (i = 0; i < num_permitted_opens; i++)
1952 xfree(permitted_opens[i].host_to_connect);
1953 num_permitted_opens = 0;
1958 /* return socket to remote host, port */
1960 connect_to(const char *host, u_short port)
1962 struct addrinfo hints, *ai, *aitop;
1963 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1967 memset(&hints, 0, sizeof(hints));
1968 hints.ai_family = IPv4or6;
1969 hints.ai_socktype = SOCK_STREAM;
1970 snprintf(strport, sizeof strport, "%d", port);
1971 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
1972 error("connect_to %.100s: unknown host (%s)", host,
1973 gai_strerror(gaierr));
1976 for (ai = aitop; ai; ai = ai->ai_next) {
1977 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1979 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1980 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1981 error("connect_to: getnameinfo failed");
1984 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1986 error("socket: %.100s", strerror(errno));
1989 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
1990 fatal("connect_to: F_SETFL: %s", strerror(errno));
1991 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
1992 errno != EINPROGRESS) {
1993 error("connect_to %.100s port %s: %.100s", ntop, strport,
1996 continue; /* fail -- try next */
1998 break; /* success */
2001 freeaddrinfo(aitop);
2003 error("connect_to %.100s port %d: failed.", host, port);
2011 channel_connect_by_listen_adress(u_short listen_port)
2015 for (i = 0; i < num_permitted_opens; i++)
2016 if (permitted_opens[i].listen_port == listen_port)
2018 permitted_opens[i].host_to_connect,
2019 permitted_opens[i].port_to_connect);
2020 error("WARNING: Server requests forwarding for unknown listen_port %d",
2025 /* Check if connecting to that port is permitted and connect. */
2027 channel_connect_to(const char *host, u_short port)
2031 permit = all_opens_permitted;
2033 for (i = 0; i < num_permitted_opens; i++)
2034 if (permitted_opens[i].port_to_connect == port &&
2035 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2040 log("Received request to connect to host %.100s port %d, "
2041 "but the request was denied.", host, port);
2044 return connect_to(host, port);
2048 * This is called after receiving PORT_OPEN message. This attempts to
2049 * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
2050 * or CHANNEL_OPEN_FAILURE.
2054 channel_input_port_open(int type, int plen, void *ctxt)
2057 char *host, *originator_string;
2058 int remote_channel, sock = -1, newch;
2060 remote_channel = packet_get_int();
2061 host = packet_get_string(NULL);
2062 host_port = packet_get_int();
2064 if (have_hostname_in_open) {
2065 originator_string = packet_get_string(NULL);
2067 originator_string = xstrdup("unknown (remote did not supply name)");
2070 sock = channel_connect_to(host, host_port);
2072 newch = channel_allocate(SSH_CHANNEL_CONNECTING,
2073 sock, originator_string);
2074 channels[newch].remote_id = remote_channel;
2076 /*XXX delay answer? */
2077 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2078 packet_put_int(remote_channel);
2079 packet_put_int(newch);
2082 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2083 packet_put_int(remote_channel);
2090 * Creates an internet domain socket for listening for X11 connections.
2091 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2095 #define NUM_SOCKS 10
2098 x11_create_display_inet(int screen_number, int x11_display_offset)
2100 int display_number, sock;
2102 struct addrinfo hints, *ai, *aitop;
2103 char strport[NI_MAXSERV];
2104 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2106 char hostname[MAXHOSTNAMELEN];
2108 for (display_number = x11_display_offset;
2109 display_number < MAX_DISPLAYS;
2111 port = 6000 + display_number;
2112 memset(&hints, 0, sizeof(hints));
2113 hints.ai_family = IPv4or6;
2114 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2115 hints.ai_socktype = SOCK_STREAM;
2116 snprintf(strport, sizeof strport, "%d", port);
2117 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2118 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2121 for (ai = aitop; ai; ai = ai->ai_next) {
2122 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2124 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2126 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2127 error("socket: %.100s", strerror(errno));
2130 debug("x11_create_display_inet: Socket family %d not supported",
2135 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2136 debug("bind port %d: %.100s", port, strerror(errno));
2137 shutdown(sock, SHUT_RDWR);
2143 for (n = 0; n < num_socks; n++) {
2144 shutdown(socks[n], SHUT_RDWR);
2150 socks[num_socks++] = sock;
2151 #ifndef DONT_TRY_OTHER_AF
2152 if (num_socks == NUM_SOCKS)
2158 freeaddrinfo(aitop);
2162 if (display_number >= MAX_DISPLAYS) {
2163 error("Failed to allocate internet-domain X11 display socket.");
2166 /* Start listening for connections on the socket. */
2167 for (n = 0; n < num_socks; n++) {
2169 if (listen(sock, 5) < 0) {
2170 error("listen: %.100s", strerror(errno));
2171 shutdown(sock, SHUT_RDWR);
2177 /* Set up a suitable value for the DISPLAY variable. */
2178 if (gethostname(hostname, sizeof(hostname)) < 0)
2179 fatal("gethostname: %.100s", strerror(errno));
2181 #ifdef IPADDR_IN_DISPLAY
2183 * HPUX detects the local hostname in the DISPLAY variable and tries
2184 * to set up a shared memory connection to the server, which it
2185 * incorrectly supposes to be local.
2187 * The workaround - as used in later $$H and other programs - is
2188 * is to set display to the host's IP address.
2192 struct in_addr my_addr;
2194 he = gethostbyname(hostname);
2196 error("[X11-broken-fwd-hostname-workaround] Could not get "
2197 "IP address for hostname %s.", hostname);
2199 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2200 "Could not get IP address for hostname %s.", hostname);
2202 shutdown(sock, SHUT_RDWR);
2208 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2210 /* Set DISPLAY to <ip address>:screen.display */
2211 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2212 display_number, screen_number);
2214 #else /* IPADDR_IN_DISPLAY */
2215 /* Just set DISPLAY to hostname:screen.display */
2216 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2217 display_number, screen_number);
2218 #endif /* IPADDR_IN_DISPLAY */
2220 /* Allocate a channel for each socket. */
2221 for (n = 0; n < num_socks; n++) {
2223 (void) channel_new("x11 listener",
2224 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2225 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2226 0, xstrdup("X11 inet listener"), 1);
2229 /* Return a suitable value for the DISPLAY environment variable. */
2230 return xstrdup(display);
2234 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2239 connect_local_xsocket(u_int dnr)
2241 static const char *const x_sockets[] = {
2243 "/var/X/.X11-unix/X" "%u",
2244 "/usr/spool/sockets/X11/" "%u",
2248 struct sockaddr_un addr;
2249 const char *const * path;
2251 for (path = x_sockets; *path; ++path) {
2252 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2254 error("socket: %.100s", strerror(errno));
2255 memset(&addr, 0, sizeof(addr));
2256 addr.sun_family = AF_UNIX;
2257 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2258 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2262 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2267 x11_connect_display(void)
2269 int display_number, sock = 0;
2270 const char *display;
2271 char buf[1024], *cp;
2272 struct addrinfo hints, *ai, *aitop;
2273 char strport[NI_MAXSERV];
2276 /* Try to open a socket for the local X server. */
2277 display = getenv("DISPLAY");
2279 error("DISPLAY not set.");
2283 * Now we decode the value of the DISPLAY variable and make a
2284 * connection to the real X server.
2288 * Check if it is a unix domain socket. Unix domain displays are in
2289 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2291 if (strncmp(display, "unix:", 5) == 0 ||
2292 display[0] == ':') {
2293 /* Connect to the unix domain socket. */
2294 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2295 error("Could not parse display number from DISPLAY: %.100s",
2299 /* Create a socket. */
2300 sock = connect_local_xsocket(display_number);
2304 /* OK, we now have a connection to the display. */
2308 * Connect to an inet socket. The DISPLAY value is supposedly
2309 * hostname:d[.s], where hostname may also be numeric IP address.
2311 strncpy(buf, display, sizeof(buf));
2312 buf[sizeof(buf) - 1] = 0;
2313 cp = strchr(buf, ':');
2315 error("Could not find ':' in DISPLAY: %.100s", display);
2319 /* buf now contains the host name. But first we parse the display number. */
2320 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2321 error("Could not parse display number from DISPLAY: %.100s",
2326 /* Look up the host address */
2327 memset(&hints, 0, sizeof(hints));
2328 hints.ai_family = IPv4or6;
2329 hints.ai_socktype = SOCK_STREAM;
2330 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2331 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2332 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2335 for (ai = aitop; ai; ai = ai->ai_next) {
2336 /* Create a socket. */
2337 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2339 debug("socket: %.100s", strerror(errno));
2342 /* Connect it to the display. */
2343 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2344 debug("connect %.100s port %d: %.100s", buf,
2345 6000 + display_number, strerror(errno));
2352 freeaddrinfo(aitop);
2354 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2362 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2363 * the remote channel number. We should do whatever we want, and respond
2364 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2368 x11_input_open(int type, int plen, void *ctxt)
2370 int remote_channel, sock = 0, newch;
2374 /* Get remote channel number. */
2375 remote_channel = packet_get_int();
2377 /* Get remote originator name. */
2378 if (have_hostname_in_open) {
2379 remote_host = packet_get_string(&remote_len);
2382 remote_host = xstrdup("unknown (remote did not supply name)");
2386 debug("Received X11 open request.");
2387 packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
2389 /* Obtain a connection to the real X display. */
2390 sock = x11_connect_display();
2392 /* Send refusal to the remote host. */
2393 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2394 packet_put_int(remote_channel);
2397 /* Allocate a channel for this connection. */
2398 newch = channel_allocate(
2399 (x11_saved_proto == NULL) ?
2400 SSH_CHANNEL_OPEN : SSH_CHANNEL_X11_OPEN,
2402 channels[newch].remote_id = remote_channel;
2404 /* Send a confirmation to the remote host. */
2405 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2406 packet_put_int(remote_channel);
2407 packet_put_int(newch);
2412 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2414 deny_input_open(int type, int plen, void *ctxt)
2416 int rchan = packet_get_int();
2418 case SSH_SMSG_AGENT_OPEN:
2419 error("Warning: ssh server tried agent forwarding.");
2421 case SSH_SMSG_X11_OPEN:
2422 error("Warning: ssh server tried X11 forwarding.");
2425 error("deny_input_open: type %d plen %d", type, plen);
2428 error("Warning: this is probably a break in attempt by a malicious server.");
2429 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2430 packet_put_int(rchan);
2435 * Requests forwarding of X11 connections, generates fake authentication
2436 * data, and enables authentication spoofing.
2440 x11_request_forwarding_with_spoofing(int client_session_id,
2441 const char *proto, const char *data)
2443 u_int data_len = (u_int) strlen(data) / 2;
2444 u_int i, value, len;
2450 cp = getenv("DISPLAY");
2452 cp = strchr(cp, ':');
2454 cp = strchr(cp, '.');
2456 screen_number = atoi(cp + 1);
2460 /* Save protocol name. */
2461 x11_saved_proto = xstrdup(proto);
2464 * Extract real authentication data and generate fake data of the
2467 x11_saved_data = xmalloc(data_len);
2468 x11_fake_data = xmalloc(data_len);
2469 for (i = 0; i < data_len; i++) {
2470 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2471 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2473 rand = arc4random();
2474 x11_saved_data[i] = value;
2475 x11_fake_data[i] = rand & 0xff;
2478 x11_saved_data_len = data_len;
2479 x11_fake_data_len = data_len;
2481 /* Convert the fake data into hex. */
2482 len = 2 * data_len + 1;
2483 new_data = xmalloc(len);
2484 for (i = 0; i < data_len; i++)
2485 snprintf(new_data + 2 * i, len - 2 * i,
2486 "%02x", (u_char) x11_fake_data[i]);
2488 /* Send the request packet. */
2490 channel_request_start(client_session_id, "x11-req", 0);
2491 packet_put_char(0); /* XXX bool single connection */
2493 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2495 packet_put_cstring(proto);
2496 packet_put_cstring(new_data);
2497 packet_put_int(screen_number);
2499 packet_write_wait();
2503 /* Sends a message to the server to request authentication fd forwarding. */
2506 auth_request_forwarding()
2508 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2510 packet_write_wait();
2514 * Returns the name of the forwarded authentication socket. Returns NULL if
2515 * there is no forwarded authentication socket. The returned value points to
2520 auth_get_socket_name()
2522 return channel_forwarded_auth_socket_name;
2525 /* removes the agent forwarding socket */
2528 cleanup_socket(void)
2530 unlink(channel_forwarded_auth_socket_name);
2531 rmdir(channel_forwarded_auth_socket_dir);
2535 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2536 * This starts forwarding authentication requests.
2540 auth_input_request_forwarding(struct passwd * pw)
2543 struct sockaddr_un sunaddr;
2545 if (auth_get_socket_name() != NULL)
2546 fatal("Protocol error: authentication forwarding requested twice.");
2548 /* Temporarily drop privileged uid for mkdir/bind. */
2549 temporarily_use_uid(pw);
2551 /* Allocate a buffer for the socket name, and format the name. */
2552 channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
2553 channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
2554 strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
2556 /* Create private directory for socket */
2557 if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL) {
2558 packet_send_debug("Agent forwarding disabled: mkdtemp() failed: %.100s",
2561 xfree(channel_forwarded_auth_socket_name);
2562 xfree(channel_forwarded_auth_socket_dir);
2563 channel_forwarded_auth_socket_name = NULL;
2564 channel_forwarded_auth_socket_dir = NULL;
2567 snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
2568 channel_forwarded_auth_socket_dir, (int) getpid());
2570 if (atexit(cleanup_socket) < 0) {
2573 packet_disconnect("socket: %.100s", strerror(saved));
2575 /* Create the socket. */
2576 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2578 packet_disconnect("socket: %.100s", strerror(errno));
2580 /* Bind it to the name. */
2581 memset(&sunaddr, 0, sizeof(sunaddr));
2582 sunaddr.sun_family = AF_UNIX;
2583 strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
2584 sizeof(sunaddr.sun_path));
2586 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2587 packet_disconnect("bind: %.100s", strerror(errno));
2589 /* Restore the privileged uid. */
2592 /* Start listening on the socket. */
2593 if (listen(sock, 5) < 0)
2594 packet_disconnect("listen: %.100s", strerror(errno));
2596 /* Allocate a channel for the authentication agent socket. */
2597 newch = channel_new("auth socket",
2598 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2599 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2600 0, xstrdup("auth socket"), 1);
2602 strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
2603 sizeof(channels[newch].path));
2607 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2610 auth_input_open_request(int type, int plen, void *ctxt)
2612 int remch, sock, newch;
2615 packet_integrity_check(plen, 4, type);
2617 /* Read the remote channel number from the message. */
2618 remch = packet_get_int();
2621 * Get a connection to the local authentication agent (this may again
2624 sock = ssh_get_authentication_socket();
2627 * If we could not connect the agent, send an error message back to
2628 * the server. This should never happen unless the agent dies,
2629 * because authentication forwarding is only enabled if we have an
2633 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2634 packet_put_int(remch);
2638 debug("Forwarding authentication connection.");
2641 * Dummy host name. This will be freed when the channel is freed; it
2642 * will still be valid in the packet_put_string below since the
2643 * channel cannot yet be freed at that point.
2645 dummyname = xstrdup("authentication agent connection");
2647 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
2648 channels[newch].remote_id = remch;
2650 /* Send a confirmation to the remote host. */
2651 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2652 packet_put_int(remch);
2653 packet_put_int(newch);
2658 channel_start_open(int id)
2660 Channel *c = channel_lookup(id);
2662 log("channel_open: %d: bad id", id);
2665 debug("send channel open %d", id);
2666 packet_start(SSH2_MSG_CHANNEL_OPEN);
2667 packet_put_cstring(c->ctype);
2668 packet_put_int(c->self);
2669 packet_put_int(c->local_window);
2670 packet_put_int(c->local_maxpacket);
2673 channel_open(int id)
2676 channel_start_open(id);
2680 channel_request(int id, char *service, int wantconfirm)
2682 channel_request_start(id, service, wantconfirm);
2684 debug("channel request %d: %s", id, service) ;
2687 channel_request_start(int id, char *service, int wantconfirm)
2689 Channel *c = channel_lookup(id);
2691 log("channel_request: %d: bad id", id);
2694 packet_start(SSH2_MSG_CHANNEL_REQUEST);
2695 packet_put_int(c->remote_id);
2696 packet_put_cstring(service);
2697 packet_put_char(wantconfirm);
2700 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
2702 Channel *c = channel_lookup(id);
2704 log("channel_register_callback: %d: bad id", id);
2707 c->cb_event = mtype;
2712 channel_register_cleanup(int id, channel_callback_fn *fn)
2714 Channel *c = channel_lookup(id);
2716 log("channel_register_cleanup: %d: bad id", id);
2719 c->dettach_user = fn;
2722 channel_cancel_cleanup(int id)
2724 Channel *c = channel_lookup(id);
2726 log("channel_cancel_cleanup: %d: bad id", id);
2729 c->dettach_user = NULL;
2732 channel_register_filter(int id, channel_filter_fn *fn)
2734 Channel *c = channel_lookup(id);
2736 log("channel_register_filter: %d: bad id", id);
2739 c->input_filter = fn;
2743 channel_set_fds(int id, int rfd, int wfd, int efd,
2744 int extusage, int nonblock)
2746 Channel *c = channel_lookup(id);
2747 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
2748 fatal("channel_activate for non-larval channel %d.", id);
2749 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
2750 c->type = SSH_CHANNEL_OPEN;
2751 /* XXX window size? */
2752 c->local_window = c->local_window_max = c->local_maxpacket * 2;
2753 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2754 packet_put_int(c->remote_id);
2755 packet_put_int(c->local_window);