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 1.200 2004/01/19 09:24:21 markus Exp $");
56 #include "pathnames.h"
62 * Pointer to an array containing all allocated channels. The array is
63 * dynamically extended as needed.
65 static Channel **channels = NULL;
68 * Size of the channel array. All slots of the array must always be
69 * initialized (at least the type field); unused slots set to NULL
71 static int channels_alloc = 0;
74 * Maximum file descriptor value used in any of the channels. This is
75 * updated in channel_new.
77 static int channel_max_fd = 0;
80 /* -- tcp forwarding */
83 * Data structure for storing which hosts are permitted for forward requests.
84 * The local sides of any remote forwards are stored in this array to prevent
85 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
86 * network (which might be behind a firewall).
89 char *host_to_connect; /* Connect to 'host'. */
90 u_short port_to_connect; /* Connect to 'port'. */
91 u_short listen_port; /* Remote side should listen port number. */
94 /* List of all permitted host/port pairs to connect. */
95 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
97 /* Number of permitted host/port pairs in the array. */
98 static int num_permitted_opens = 0;
100 * If this is true, all opens are permitted. This is the case on the server
101 * on which we have to trust the client anyway, and the user could do
102 * anything after logging in anyway.
104 static int all_opens_permitted = 0;
107 /* -- X11 forwarding */
109 /* Maximum number of fake X11 displays to try. */
110 #define MAX_DISPLAYS 1000
112 /* Saved X11 authentication protocol name. */
113 static char *x11_saved_proto = NULL;
115 /* Saved X11 authentication data. This is the real data. */
116 static char *x11_saved_data = NULL;
117 static u_int x11_saved_data_len = 0;
120 * Fake X11 authentication data. This is what the server will be sending us;
121 * we should replace any occurrences of this by the real data.
123 static char *x11_fake_data = NULL;
124 static u_int x11_fake_data_len;
127 /* -- agent forwarding */
131 /* AF_UNSPEC or AF_INET or AF_INET6 */
132 static int IPv4or6 = AF_UNSPEC;
135 static void port_open_helper(Channel *c, char *rtype);
137 /* -- channel core */
140 channel_lookup(int id)
144 if (id < 0 || id >= channels_alloc) {
145 logit("channel_lookup: %d: bad id", id);
150 logit("channel_lookup: %d: bad id: channel free", id);
157 * Register filedescriptors for a channel, used when allocating a channel or
158 * when the channel consumer/producer is ready, e.g. shell exec'd
162 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
163 int extusage, int nonblock)
165 /* Update the maximum file descriptor value. */
166 channel_max_fd = MAX(channel_max_fd, rfd);
167 channel_max_fd = MAX(channel_max_fd, wfd);
168 channel_max_fd = MAX(channel_max_fd, efd);
170 /* XXX set close-on-exec -markus */
174 c->sock = (rfd == wfd) ? rfd : -1;
176 c->extended_usage = extusage;
178 /* XXX ugly hack: nonblock is only set by the server */
179 if (nonblock && isatty(c->rfd)) {
180 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
182 if (!isatty(c->wfd)) {
183 error("channel %d: wfd %d is not a tty?",
189 c->wfd_isatty = isatty(c->wfd);
191 /* enable nonblocking mode */
203 * Allocate a new channel object and set its type and socket. This will cause
204 * remote_name to be freed.
208 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
209 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
214 /* Do initial allocation if this is the first call. */
215 if (channels_alloc == 0) {
217 channels = xmalloc(channels_alloc * sizeof(Channel *));
218 for (i = 0; i < channels_alloc; i++)
221 /* Try to find a free slot where to put the new channel. */
222 for (found = -1, i = 0; i < channels_alloc; i++)
223 if (channels[i] == NULL) {
224 /* Found a free slot. */
229 /* There are no free slots. Take last+1 slot and expand the array. */
230 found = channels_alloc;
231 if (channels_alloc > 10000)
232 fatal("channel_new: internal error: channels_alloc %d "
233 "too big.", channels_alloc);
234 channels = xrealloc(channels,
235 (channels_alloc + 10) * sizeof(Channel *));
236 channels_alloc += 10;
237 debug2("channel: expanding %d", channels_alloc);
238 for (i = found; i < channels_alloc; i++)
241 /* Initialize and return new channel. */
242 c = channels[found] = xmalloc(sizeof(Channel));
243 memset(c, 0, sizeof(Channel));
244 buffer_init(&c->input);
245 buffer_init(&c->output);
246 buffer_init(&c->extended);
247 c->ostate = CHAN_OUTPUT_OPEN;
248 c->istate = CHAN_INPUT_OPEN;
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 = xstrdup(remote_name);
260 c->remote_window = 0;
261 c->remote_maxpacket = 0;
263 c->single_connection = 0;
264 c->detach_user = NULL;
266 c->input_filter = NULL;
267 debug("channel %d: new [%s]", found, remote_name);
272 channel_find_maxfd(void)
277 for (i = 0; i < channels_alloc; i++) {
280 max = MAX(max, c->rfd);
281 max = MAX(max, c->wfd);
282 max = MAX(max, c->efd);
289 channel_close_fd(int *fdp)
291 int ret = 0, fd = *fdp;
296 if (fd == channel_max_fd)
297 channel_max_fd = channel_find_maxfd();
302 /* Close all channel fd/socket. */
305 channel_close_fds(Channel *c)
307 debug3("channel %d: close_fds r %d w %d e %d",
308 c->self, c->rfd, c->wfd, c->efd);
310 channel_close_fd(&c->sock);
311 channel_close_fd(&c->rfd);
312 channel_close_fd(&c->wfd);
313 channel_close_fd(&c->efd);
316 /* Free the channel and close its fd/socket. */
319 channel_free(Channel *c)
324 for (n = 0, i = 0; i < channels_alloc; i++)
327 debug("channel %d: free: %s, nchannels %d", c->self,
328 c->remote_name ? c->remote_name : "???", n);
330 s = channel_open_message();
331 debug3("channel %d: status: %s", c->self, s);
335 shutdown(c->sock, SHUT_RDWR);
336 channel_close_fds(c);
337 buffer_free(&c->input);
338 buffer_free(&c->output);
339 buffer_free(&c->extended);
340 if (c->remote_name) {
341 xfree(c->remote_name);
342 c->remote_name = NULL;
344 channels[c->self] = NULL;
349 channel_free_all(void)
353 for (i = 0; i < channels_alloc; i++)
354 if (channels[i] != NULL)
355 channel_free(channels[i]);
359 * Closes the sockets/fds of all channels. This is used to close extra file
360 * descriptors after a fork.
364 channel_close_all(void)
368 for (i = 0; i < channels_alloc; i++)
369 if (channels[i] != NULL)
370 channel_close_fds(channels[i]);
374 * Stop listening to channels.
378 channel_stop_listening(void)
383 for (i = 0; i < channels_alloc; i++) {
387 case SSH_CHANNEL_AUTH_SOCKET:
388 case SSH_CHANNEL_PORT_LISTENER:
389 case SSH_CHANNEL_RPORT_LISTENER:
390 case SSH_CHANNEL_X11_LISTENER:
391 channel_close_fd(&c->sock);
400 * Returns true if no channel has too much buffered data, and false if one or
401 * more channel is overfull.
405 channel_not_very_much_buffered_data(void)
410 for (i = 0; i < channels_alloc; i++) {
412 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
415 buffer_len(&c->input) > packet_get_maxsize()) {
416 debug2("channel %d: big input buffer %d",
417 c->self, buffer_len(&c->input));
421 if (buffer_len(&c->output) > packet_get_maxsize()) {
422 debug2("channel %d: big output buffer %u > %u",
423 c->self, buffer_len(&c->output),
424 packet_get_maxsize());
432 /* Returns true if any channel is still open. */
435 channel_still_open(void)
440 for (i = 0; i < channels_alloc; i++) {
445 case SSH_CHANNEL_X11_LISTENER:
446 case SSH_CHANNEL_PORT_LISTENER:
447 case SSH_CHANNEL_RPORT_LISTENER:
448 case SSH_CHANNEL_CLOSED:
449 case SSH_CHANNEL_AUTH_SOCKET:
450 case SSH_CHANNEL_DYNAMIC:
451 case SSH_CHANNEL_CONNECTING:
452 case SSH_CHANNEL_ZOMBIE:
454 case SSH_CHANNEL_LARVAL:
456 fatal("cannot happen: SSH_CHANNEL_LARVAL");
458 case SSH_CHANNEL_OPENING:
459 case SSH_CHANNEL_OPEN:
460 case SSH_CHANNEL_X11_OPEN:
462 case SSH_CHANNEL_INPUT_DRAINING:
463 case SSH_CHANNEL_OUTPUT_DRAINING:
465 fatal("cannot happen: OUT_DRAIN");
468 fatal("channel_still_open: bad channel type %d", c->type);
475 /* Returns the id of an open channel suitable for keepaliving */
478 channel_find_open(void)
483 for (i = 0; i < channels_alloc; i++) {
488 case SSH_CHANNEL_CLOSED:
489 case SSH_CHANNEL_DYNAMIC:
490 case SSH_CHANNEL_X11_LISTENER:
491 case SSH_CHANNEL_PORT_LISTENER:
492 case SSH_CHANNEL_RPORT_LISTENER:
493 case SSH_CHANNEL_OPENING:
494 case SSH_CHANNEL_CONNECTING:
495 case SSH_CHANNEL_ZOMBIE:
497 case SSH_CHANNEL_LARVAL:
498 case SSH_CHANNEL_AUTH_SOCKET:
499 case SSH_CHANNEL_OPEN:
500 case SSH_CHANNEL_X11_OPEN:
502 case SSH_CHANNEL_INPUT_DRAINING:
503 case SSH_CHANNEL_OUTPUT_DRAINING:
505 fatal("cannot happen: OUT_DRAIN");
508 fatal("channel_find_open: bad channel type %d", c->type);
517 * Returns a message describing the currently open forwarded connections,
518 * suitable for sending to the client. The message contains crlf pairs for
523 channel_open_message(void)
530 buffer_init(&buffer);
531 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
532 buffer_append(&buffer, buf, strlen(buf));
533 for (i = 0; i < channels_alloc; i++) {
538 case SSH_CHANNEL_X11_LISTENER:
539 case SSH_CHANNEL_PORT_LISTENER:
540 case SSH_CHANNEL_RPORT_LISTENER:
541 case SSH_CHANNEL_CLOSED:
542 case SSH_CHANNEL_AUTH_SOCKET:
543 case SSH_CHANNEL_ZOMBIE:
545 case SSH_CHANNEL_LARVAL:
546 case SSH_CHANNEL_OPENING:
547 case SSH_CHANNEL_CONNECTING:
548 case SSH_CHANNEL_DYNAMIC:
549 case SSH_CHANNEL_OPEN:
550 case SSH_CHANNEL_X11_OPEN:
551 case SSH_CHANNEL_INPUT_DRAINING:
552 case SSH_CHANNEL_OUTPUT_DRAINING:
553 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
554 c->self, c->remote_name,
555 c->type, c->remote_id,
556 c->istate, buffer_len(&c->input),
557 c->ostate, buffer_len(&c->output),
559 buffer_append(&buffer, buf, strlen(buf));
562 fatal("channel_open_message: bad channel type %d", c->type);
566 buffer_append(&buffer, "\0", 1);
567 cp = xstrdup(buffer_ptr(&buffer));
568 buffer_free(&buffer);
573 channel_send_open(int id)
575 Channel *c = channel_lookup(id);
578 logit("channel_send_open: %d: bad id", id);
581 debug2("channel %d: send open", id);
582 packet_start(SSH2_MSG_CHANNEL_OPEN);
583 packet_put_cstring(c->ctype);
584 packet_put_int(c->self);
585 packet_put_int(c->local_window);
586 packet_put_int(c->local_maxpacket);
591 channel_request_start(int id, char *service, int wantconfirm)
593 Channel *c = channel_lookup(id);
596 logit("channel_request_start: %d: unknown channel id", id);
599 debug2("channel %d: request %s", id, service) ;
600 packet_start(SSH2_MSG_CHANNEL_REQUEST);
601 packet_put_int(c->remote_id);
602 packet_put_cstring(service);
603 packet_put_char(wantconfirm);
606 channel_register_confirm(int id, channel_callback_fn *fn)
608 Channel *c = channel_lookup(id);
611 logit("channel_register_comfirm: %d: bad id", id);
617 channel_register_cleanup(int id, channel_callback_fn *fn)
619 Channel *c = channel_lookup(id);
622 logit("channel_register_cleanup: %d: bad id", id);
628 channel_cancel_cleanup(int id)
630 Channel *c = channel_lookup(id);
633 logit("channel_cancel_cleanup: %d: bad id", id);
636 c->detach_user = NULL;
639 channel_register_filter(int id, channel_filter_fn *fn)
641 Channel *c = channel_lookup(id);
644 logit("channel_register_filter: %d: bad id", id);
647 c->input_filter = fn;
651 channel_set_fds(int id, int rfd, int wfd, int efd,
652 int extusage, int nonblock, u_int window_max)
654 Channel *c = channel_lookup(id);
656 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
657 fatal("channel_activate for non-larval channel %d.", id);
658 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
659 c->type = SSH_CHANNEL_OPEN;
660 c->local_window = c->local_window_max = window_max;
661 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
662 packet_put_int(c->remote_id);
663 packet_put_int(c->local_window);
668 * 'channel_pre*' are called just before select() to add any bits relevant to
669 * channels in the select bitmasks.
672 * 'channel_post*': perform any appropriate operations for channels which
673 * have events pending.
675 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
676 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
677 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
680 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
682 FD_SET(c->sock, readset);
686 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
688 debug3("channel %d: waiting for connection", c->self);
689 FD_SET(c->sock, writeset);
693 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
695 if (buffer_len(&c->input) < packet_get_maxsize())
696 FD_SET(c->sock, readset);
697 if (buffer_len(&c->output) > 0)
698 FD_SET(c->sock, writeset);
702 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
704 u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
706 if (c->istate == CHAN_INPUT_OPEN &&
708 buffer_len(&c->input) < limit)
709 FD_SET(c->rfd, readset);
710 if (c->ostate == CHAN_OUTPUT_OPEN ||
711 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
712 if (buffer_len(&c->output) > 0) {
713 FD_SET(c->wfd, writeset);
714 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
715 if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
716 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
717 c->self, c->efd, buffer_len(&c->extended));
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->flags & CHAN_EOF_SENT) &&
728 c->extended_usage == CHAN_EXTENDED_READ &&
729 buffer_len(&c->extended) < c->remote_window)
730 FD_SET(c->efd, readset);
735 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
737 if (buffer_len(&c->input) == 0) {
738 packet_start(SSH_MSG_CHANNEL_CLOSE);
739 packet_put_int(c->remote_id);
741 c->type = SSH_CHANNEL_CLOSED;
742 debug2("channel %d: closing after input drain.", c->self);
747 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
749 if (buffer_len(&c->output) == 0)
752 FD_SET(c->sock, writeset);
756 * This is a special state for X11 authentication spoofing. An opened X11
757 * connection (when authentication spoofing is being done) remains in this
758 * state until the first packet has been completely read. The authentication
759 * data in that packet is then substituted by the real data if it matches the
760 * fake data, and the channel is put into normal mode.
761 * XXX All this happens at the client side.
762 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
765 x11_open_helper(Buffer *b)
768 u_int proto_len, data_len;
770 /* Check if the fixed size part of the packet is in buffer. */
771 if (buffer_len(b) < 12)
774 /* Parse the lengths of variable-length fields. */
776 if (ucp[0] == 0x42) { /* Byte order MSB first. */
777 proto_len = 256 * ucp[6] + ucp[7];
778 data_len = 256 * ucp[8] + ucp[9];
779 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
780 proto_len = ucp[6] + 256 * ucp[7];
781 data_len = ucp[8] + 256 * ucp[9];
783 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
788 /* Check if the whole packet is in buffer. */
790 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
793 /* Check if authentication protocol matches. */
794 if (proto_len != strlen(x11_saved_proto) ||
795 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
796 debug2("X11 connection uses different authentication protocol.");
799 /* Check if authentication data matches our fake data. */
800 if (data_len != x11_fake_data_len ||
801 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
802 x11_fake_data, x11_fake_data_len) != 0) {
803 debug2("X11 auth data does not match fake data.");
806 /* Check fake data length */
807 if (x11_fake_data_len != x11_saved_data_len) {
808 error("X11 fake_data_len %d != saved_data_len %d",
809 x11_fake_data_len, x11_saved_data_len);
813 * Received authentication protocol and data match
814 * our fake data. Substitute the fake data with real
817 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
818 x11_saved_data, x11_saved_data_len);
823 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
825 int ret = x11_open_helper(&c->output);
828 /* Start normal processing for the channel. */
829 c->type = SSH_CHANNEL_OPEN;
830 channel_pre_open_13(c, readset, writeset);
831 } else if (ret == -1) {
833 * We have received an X11 connection that has bad
834 * authentication information.
836 logit("X11 connection rejected because of wrong authentication.");
837 buffer_clear(&c->input);
838 buffer_clear(&c->output);
839 channel_close_fd(&c->sock);
841 c->type = SSH_CHANNEL_CLOSED;
842 packet_start(SSH_MSG_CHANNEL_CLOSE);
843 packet_put_int(c->remote_id);
849 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
851 int ret = x11_open_helper(&c->output);
853 /* c->force_drain = 1; */
856 c->type = SSH_CHANNEL_OPEN;
857 channel_pre_open(c, readset, writeset);
858 } else if (ret == -1) {
859 logit("X11 connection rejected because of wrong authentication.");
860 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
862 buffer_clear(&c->input);
864 buffer_clear(&c->output);
865 /* for proto v1, the peer will send an IEOF */
867 chan_write_failed(c);
869 c->type = SSH_CHANNEL_OPEN;
870 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
874 /* try to decode a socks4 header */
876 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
879 int len, have, i, found;
885 struct in_addr dest_addr;
888 debug2("channel %d: decode socks4", c->self);
890 have = buffer_len(&c->input);
891 len = sizeof(s4_req);
894 p = buffer_ptr(&c->input);
895 for (found = 0, i = len; i < have; i++) {
901 /* the peer is probably sending garbage */
902 debug("channel %d: decode socks4: too long",
909 buffer_get(&c->input, (char *)&s4_req.version, 1);
910 buffer_get(&c->input, (char *)&s4_req.command, 1);
911 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
912 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
913 have = buffer_len(&c->input);
914 p = buffer_ptr(&c->input);
916 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
918 fatal("channel %d: decode socks4: len %d > have %d",
920 strlcpy(username, p, sizeof(username));
921 buffer_consume(&c->input, len);
922 buffer_consume(&c->input, 1); /* trailing '\0' */
924 host = inet_ntoa(s4_req.dest_addr);
925 strlcpy(c->path, host, sizeof(c->path));
926 c->host_port = ntohs(s4_req.dest_port);
928 debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
929 c->self, host, c->host_port, s4_req.command);
931 if (s4_req.command != 1) {
932 debug("channel %d: cannot handle: socks4 cn %d",
933 c->self, s4_req.command);
936 s4_rsp.version = 0; /* vn: 0 for reply */
937 s4_rsp.command = 90; /* cd: req granted */
938 s4_rsp.dest_port = 0; /* ignored */
939 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
940 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
944 /* try to decode a socks5 header */
945 #define SSH_SOCKS5_AUTHDONE 0x1000
946 #define SSH_SOCKS5_NOAUTH 0x00
947 #define SSH_SOCKS5_IPV4 0x01
948 #define SSH_SOCKS5_DOMAIN 0x03
949 #define SSH_SOCKS5_IPV6 0x04
950 #define SSH_SOCKS5_CONNECT 0x01
951 #define SSH_SOCKS5_SUCCESS 0x00
954 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
963 u_char *p, dest_addr[255+1];
964 int i, have, found, nmethods, addrlen, af;
966 debug2("channel %d: decode socks5", c->self);
967 p = buffer_ptr(&c->input);
970 have = buffer_len(&c->input);
971 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
972 /* format: ver | nmethods | methods */
976 if (have < nmethods + 2)
978 /* look for method: "NO AUTHENTICATION REQUIRED" */
979 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
980 if (p[i] == SSH_SOCKS5_NOAUTH ) {
986 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
990 buffer_consume(&c->input, nmethods + 2);
991 buffer_put_char(&c->output, 0x05); /* version */
992 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
993 FD_SET(c->sock, writeset);
994 c->flags |= SSH_SOCKS5_AUTHDONE;
995 debug2("channel %d: socks5 auth done", c->self);
996 return 0; /* need more */
998 debug2("channel %d: socks5 post auth", c->self);
999 if (have < sizeof(s5_req)+1)
1000 return 0; /* need more */
1001 memcpy((char *)&s5_req, p, sizeof(s5_req));
1002 if (s5_req.version != 0x05 ||
1003 s5_req.command != SSH_SOCKS5_CONNECT ||
1004 s5_req.reserved != 0x00) {
1005 debug2("channel %d: only socks5 connect supported", c->self);
1008 switch(s5_req.atyp){
1009 case SSH_SOCKS5_IPV4:
1013 case SSH_SOCKS5_DOMAIN:
1014 addrlen = p[sizeof(s5_req)];
1017 case SSH_SOCKS5_IPV6:
1022 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1025 if (have < 4 + addrlen + 2)
1027 buffer_consume(&c->input, sizeof(s5_req));
1028 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1029 buffer_consume(&c->input, 1); /* host string length */
1030 buffer_get(&c->input, (char *)&dest_addr, addrlen);
1031 buffer_get(&c->input, (char *)&dest_port, 2);
1032 dest_addr[addrlen] = '\0';
1033 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1034 strlcpy(c->path, dest_addr, sizeof(c->path));
1035 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
1037 c->host_port = ntohs(dest_port);
1039 debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1040 c->self, c->path, c->host_port, s5_req.command);
1042 s5_rsp.version = 0x05;
1043 s5_rsp.command = SSH_SOCKS5_SUCCESS;
1044 s5_rsp.reserved = 0; /* ignored */
1045 s5_rsp.atyp = SSH_SOCKS5_IPV4;
1046 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1047 dest_port = 0; /* ignored */
1049 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
1050 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
1051 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
1055 /* dynamic port forwarding */
1057 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
1062 have = buffer_len(&c->input);
1064 debug2("channel %d: pre_dynamic: have %d", c->self, have);
1065 /* buffer_dump(&c->input); */
1066 /* check if the fixed size part of the packet is in buffer. */
1069 FD_SET(c->sock, readset);
1072 /* try to guess the protocol */
1073 p = buffer_ptr(&c->input);
1076 ret = channel_decode_socks4(c, readset, writeset);
1079 ret = channel_decode_socks5(c, readset, writeset);
1087 } else if (ret == 0) {
1088 debug2("channel %d: pre_dynamic: need more", c->self);
1090 FD_SET(c->sock, readset);
1092 /* switch to the next state */
1093 c->type = SSH_CHANNEL_OPENING;
1094 port_open_helper(c, "direct-tcpip");
1098 /* This is our fake X11 server socket. */
1100 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
1103 struct sockaddr addr;
1106 char buf[16384], *remote_ipaddr;
1109 if (FD_ISSET(c->sock, readset)) {
1110 debug("X11 connection requested.");
1111 addrlen = sizeof(addr);
1112 newsock = accept(c->sock, &addr, &addrlen);
1113 if (c->single_connection) {
1114 debug2("single_connection: closing X11 listener.");
1115 channel_close_fd(&c->sock);
1119 error("accept: %.100s", strerror(errno));
1122 set_nodelay(newsock);
1123 remote_ipaddr = get_peer_ipaddr(newsock);
1124 remote_port = get_peer_port(newsock);
1125 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1126 remote_ipaddr, remote_port);
1128 nc = channel_new("accepted x11 socket",
1129 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1130 c->local_window_max, c->local_maxpacket, 0, buf, 1);
1132 packet_start(SSH2_MSG_CHANNEL_OPEN);
1133 packet_put_cstring("x11");
1134 packet_put_int(nc->self);
1135 packet_put_int(nc->local_window_max);
1136 packet_put_int(nc->local_maxpacket);
1137 /* originator ipaddr and port */
1138 packet_put_cstring(remote_ipaddr);
1139 if (datafellows & SSH_BUG_X11FWD) {
1140 debug2("ssh2 x11 bug compat mode");
1142 packet_put_int(remote_port);
1146 packet_start(SSH_SMSG_X11_OPEN);
1147 packet_put_int(nc->self);
1148 if (packet_get_protocol_flags() &
1149 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1150 packet_put_cstring(buf);
1153 xfree(remote_ipaddr);
1158 port_open_helper(Channel *c, char *rtype)
1162 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1163 u_short remote_port = get_peer_port(c->sock);
1165 direct = (strcmp(rtype, "direct-tcpip") == 0);
1167 snprintf(buf, sizeof buf,
1168 "%s: listening port %d for %.100s port %d, "
1169 "connect from %.200s port %d",
1170 rtype, c->listening_port, c->path, c->host_port,
1171 remote_ipaddr, remote_port);
1173 xfree(c->remote_name);
1174 c->remote_name = xstrdup(buf);
1177 packet_start(SSH2_MSG_CHANNEL_OPEN);
1178 packet_put_cstring(rtype);
1179 packet_put_int(c->self);
1180 packet_put_int(c->local_window_max);
1181 packet_put_int(c->local_maxpacket);
1183 /* target host, port */
1184 packet_put_cstring(c->path);
1185 packet_put_int(c->host_port);
1187 /* listen address, port */
1188 packet_put_cstring(c->path);
1189 packet_put_int(c->listening_port);
1191 /* originator host and port */
1192 packet_put_cstring(remote_ipaddr);
1193 packet_put_int(remote_port);
1196 packet_start(SSH_MSG_PORT_OPEN);
1197 packet_put_int(c->self);
1198 packet_put_cstring(c->path);
1199 packet_put_int(c->host_port);
1200 if (packet_get_protocol_flags() &
1201 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1202 packet_put_cstring(c->remote_name);
1205 xfree(remote_ipaddr);
1209 * This socket is listening for connections to a forwarded TCP/IP port.
1212 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1215 struct sockaddr addr;
1216 int newsock, nextstate;
1220 if (FD_ISSET(c->sock, readset)) {
1221 debug("Connection to port %d forwarding "
1222 "to %.100s port %d requested.",
1223 c->listening_port, c->path, c->host_port);
1225 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1226 nextstate = SSH_CHANNEL_OPENING;
1227 rtype = "forwarded-tcpip";
1229 if (c->host_port == 0) {
1230 nextstate = SSH_CHANNEL_DYNAMIC;
1231 rtype = "dynamic-tcpip";
1233 nextstate = SSH_CHANNEL_OPENING;
1234 rtype = "direct-tcpip";
1238 addrlen = sizeof(addr);
1239 newsock = accept(c->sock, &addr, &addrlen);
1241 error("accept: %.100s", strerror(errno));
1244 set_nodelay(newsock);
1245 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1246 c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1247 nc->listening_port = c->listening_port;
1248 nc->host_port = c->host_port;
1249 strlcpy(nc->path, c->path, sizeof(nc->path));
1251 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1253 * do not call the channel_post handler until
1254 * this flag has been reset by a pre-handler.
1255 * otherwise the FD_ISSET calls might overflow
1259 port_open_helper(nc, rtype);
1265 * This is the authentication agent socket listening for connections from
1269 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1273 struct sockaddr addr;
1276 if (FD_ISSET(c->sock, readset)) {
1277 addrlen = sizeof(addr);
1278 newsock = accept(c->sock, &addr, &addrlen);
1280 error("accept from auth socket: %.100s", strerror(errno));
1283 nc = channel_new("accepted auth socket",
1284 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1285 c->local_window_max, c->local_maxpacket,
1286 0, "accepted auth socket", 1);
1288 packet_start(SSH2_MSG_CHANNEL_OPEN);
1289 packet_put_cstring("auth-agent@openssh.com");
1290 packet_put_int(nc->self);
1291 packet_put_int(c->local_window_max);
1292 packet_put_int(c->local_maxpacket);
1294 packet_start(SSH_SMSG_AGENT_OPEN);
1295 packet_put_int(nc->self);
1302 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1305 socklen_t sz = sizeof(err);
1307 if (FD_ISSET(c->sock, writeset)) {
1308 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1310 error("getsockopt SO_ERROR failed");
1313 debug("channel %d: connected", c->self);
1314 c->type = SSH_CHANNEL_OPEN;
1316 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1317 packet_put_int(c->remote_id);
1318 packet_put_int(c->self);
1319 packet_put_int(c->local_window);
1320 packet_put_int(c->local_maxpacket);
1322 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1323 packet_put_int(c->remote_id);
1324 packet_put_int(c->self);
1327 debug("channel %d: not connected: %s",
1328 c->self, strerror(err));
1330 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1331 packet_put_int(c->remote_id);
1332 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1333 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1334 packet_put_cstring(strerror(err));
1335 packet_put_cstring("");
1338 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1339 packet_put_int(c->remote_id);
1348 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1354 FD_ISSET(c->rfd, readset)) {
1355 len = read(c->rfd, buf, sizeof(buf));
1356 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1359 debug2("channel %d: read<=0 rfd %d len %d",
1360 c->self, c->rfd, len);
1361 if (c->type != SSH_CHANNEL_OPEN) {
1362 debug2("channel %d: not open", c->self);
1365 } else if (compat13) {
1366 buffer_clear(&c->output);
1367 c->type = SSH_CHANNEL_INPUT_DRAINING;
1368 debug2("channel %d: input draining.", c->self);
1370 chan_read_failed(c);
1374 if (c->input_filter != NULL) {
1375 if (c->input_filter(c, buf, len) == -1) {
1376 debug2("channel %d: filter stops", c->self);
1377 chan_read_failed(c);
1380 buffer_append(&c->input, buf, len);
1386 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1393 /* Send buffered output data to the socket. */
1395 FD_ISSET(c->wfd, writeset) &&
1396 buffer_len(&c->output) > 0) {
1397 data = buffer_ptr(&c->output);
1398 dlen = buffer_len(&c->output);
1400 /* XXX: Later AIX versions can't push as much data to tty */
1401 if (compat20 && c->wfd_isatty)
1402 dlen = MIN(dlen, 8*1024);
1404 len = write(c->wfd, data, dlen);
1405 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1408 if (c->type != SSH_CHANNEL_OPEN) {
1409 debug2("channel %d: not open", c->self);
1412 } else if (compat13) {
1413 buffer_clear(&c->output);
1414 debug2("channel %d: input draining.", c->self);
1415 c->type = SSH_CHANNEL_INPUT_DRAINING;
1417 chan_write_failed(c);
1421 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1422 if (tcgetattr(c->wfd, &tio) == 0 &&
1423 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1425 * Simulate echo to reduce the impact of
1426 * traffic analysis. We need to match the
1427 * size of a SSH2_MSG_CHANNEL_DATA message
1428 * (4 byte channel id + data)
1430 packet_send_ignore(4 + len);
1434 buffer_consume(&c->output, len);
1435 if (compat20 && len > 0) {
1436 c->local_consumed += len;
1442 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1447 /** XXX handle drain efd, too */
1449 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1450 FD_ISSET(c->efd, writeset) &&
1451 buffer_len(&c->extended) > 0) {
1452 len = write(c->efd, buffer_ptr(&c->extended),
1453 buffer_len(&c->extended));
1454 debug2("channel %d: written %d to efd %d",
1455 c->self, len, c->efd);
1456 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1459 debug2("channel %d: closing write-efd %d",
1461 channel_close_fd(&c->efd);
1463 buffer_consume(&c->extended, len);
1464 c->local_consumed += len;
1466 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1467 FD_ISSET(c->efd, readset)) {
1468 len = read(c->efd, buf, sizeof(buf));
1469 debug2("channel %d: read %d from efd %d",
1470 c->self, len, c->efd);
1471 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1474 debug2("channel %d: closing read-efd %d",
1476 channel_close_fd(&c->efd);
1478 buffer_append(&c->extended, buf, len);
1485 channel_check_window(Channel *c)
1487 if (c->type == SSH_CHANNEL_OPEN &&
1488 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1489 c->local_window < c->local_window_max/2 &&
1490 c->local_consumed > 0) {
1491 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1492 packet_put_int(c->remote_id);
1493 packet_put_int(c->local_consumed);
1495 debug2("channel %d: window %d sent adjust %d",
1496 c->self, c->local_window,
1498 c->local_window += c->local_consumed;
1499 c->local_consumed = 0;
1505 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
1509 channel_handle_rfd(c, readset, writeset);
1510 channel_handle_wfd(c, readset, writeset);
1513 channel_handle_efd(c, readset, writeset);
1514 channel_check_window(c);
1518 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1522 /* Send buffered output data to the socket. */
1523 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1524 len = write(c->sock, buffer_ptr(&c->output),
1525 buffer_len(&c->output));
1527 buffer_clear(&c->output);
1529 buffer_consume(&c->output, len);
1534 channel_handler_init_20(void)
1536 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1537 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1538 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1539 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1540 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1541 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1542 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1543 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1545 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1546 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1547 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1548 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1549 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1550 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1551 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1555 channel_handler_init_13(void)
1557 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1558 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1559 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1560 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1561 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1562 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1563 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1564 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1565 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1567 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1568 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1569 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1570 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1571 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1572 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1573 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1577 channel_handler_init_15(void)
1579 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
1580 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1581 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1582 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1583 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1584 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1585 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1587 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1588 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1589 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1590 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
1591 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1592 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
1596 channel_handler_init(void)
1600 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1601 channel_pre[i] = NULL;
1602 channel_post[i] = NULL;
1605 channel_handler_init_20();
1607 channel_handler_init_13();
1609 channel_handler_init_15();
1612 /* gc dead channels */
1614 channel_garbage_collect(Channel *c)
1618 if (c->detach_user != NULL) {
1619 if (!chan_is_dead(c, 0))
1621 debug2("channel %d: gc: notify user", c->self);
1622 c->detach_user(c->self, NULL);
1623 /* if we still have a callback */
1624 if (c->detach_user != NULL)
1626 debug2("channel %d: gc: user detached", c->self);
1628 if (!chan_is_dead(c, 1))
1630 debug2("channel %d: garbage collecting", c->self);
1635 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1637 static int did_init = 0;
1642 channel_handler_init();
1645 for (i = 0; i < channels_alloc; i++) {
1649 if (ftab[c->type] != NULL)
1650 (*ftab[c->type])(c, readset, writeset);
1651 channel_garbage_collect(c);
1656 * Allocate/update select bitmasks and add any bits relevant to channels in
1660 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1661 int *nallocp, int rekeying)
1666 n = MAX(*maxfdp, channel_max_fd);
1668 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1669 /* perhaps check sz < nalloc/2 and shrink? */
1670 if (*readsetp == NULL || sz > *nallocp) {
1671 *readsetp = xrealloc(*readsetp, sz);
1672 *writesetp = xrealloc(*writesetp, sz);
1676 memset(*readsetp, 0, sz);
1677 memset(*writesetp, 0, sz);
1680 channel_handler(channel_pre, *readsetp, *writesetp);
1684 * After select, perform any appropriate operations for channels which have
1688 channel_after_select(fd_set * readset, fd_set * writeset)
1690 channel_handler(channel_post, readset, writeset);
1694 /* If there is data to send to the connection, enqueue some of it now. */
1697 channel_output_poll(void)
1703 for (i = 0; i < channels_alloc; i++) {
1709 * We are only interested in channels that can have buffered
1713 if (c->type != SSH_CHANNEL_OPEN &&
1714 c->type != SSH_CHANNEL_INPUT_DRAINING)
1717 if (c->type != SSH_CHANNEL_OPEN)
1721 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1722 /* XXX is this true? */
1723 debug3("channel %d: will not send data after close", c->self);
1727 /* Get the amount of buffered data for this channel. */
1728 if ((c->istate == CHAN_INPUT_OPEN ||
1729 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1730 (len = buffer_len(&c->input)) > 0) {
1732 * Send some data for the other side over the secure
1736 if (len > c->remote_window)
1737 len = c->remote_window;
1738 if (len > c->remote_maxpacket)
1739 len = c->remote_maxpacket;
1741 if (packet_is_interactive()) {
1745 /* Keep the packets at reasonable size. */
1746 if (len > packet_get_maxsize()/2)
1747 len = packet_get_maxsize()/2;
1751 packet_start(compat20 ?
1752 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1753 packet_put_int(c->remote_id);
1754 packet_put_string(buffer_ptr(&c->input), len);
1756 buffer_consume(&c->input, len);
1757 c->remote_window -= len;
1759 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1761 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1763 * input-buffer is empty and read-socket shutdown:
1764 * tell peer, that we will not send more data: send IEOF.
1765 * hack for extended data: delay EOF if EFD still in use.
1767 if (CHANNEL_EFD_INPUT_ACTIVE(c))
1768 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
1769 c->self, c->efd, buffer_len(&c->extended));
1773 /* Send extended data, i.e. stderr */
1775 !(c->flags & CHAN_EOF_SENT) &&
1776 c->remote_window > 0 &&
1777 (len = buffer_len(&c->extended)) > 0 &&
1778 c->extended_usage == CHAN_EXTENDED_READ) {
1779 debug2("channel %d: rwin %u elen %u euse %d",
1780 c->self, c->remote_window, buffer_len(&c->extended),
1782 if (len > c->remote_window)
1783 len = c->remote_window;
1784 if (len > c->remote_maxpacket)
1785 len = c->remote_maxpacket;
1786 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1787 packet_put_int(c->remote_id);
1788 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1789 packet_put_string(buffer_ptr(&c->extended), len);
1791 buffer_consume(&c->extended, len);
1792 c->remote_window -= len;
1793 debug2("channel %d: sent ext data %d", c->self, len);
1799 /* -- protocol input */
1802 channel_input_data(int type, u_int32_t seq, void *ctxt)
1809 /* Get the channel number and verify it. */
1810 id = packet_get_int();
1811 c = channel_lookup(id);
1813 packet_disconnect("Received data for nonexistent channel %d.", id);
1815 /* Ignore any data for non-open channels (might happen on close) */
1816 if (c->type != SSH_CHANNEL_OPEN &&
1817 c->type != SSH_CHANNEL_X11_OPEN)
1821 data = packet_get_string(&data_len);
1824 * Ignore data for protocol > 1.3 if output end is no longer open.
1825 * For protocol 2 the sending side is reducing its window as it sends
1826 * data, so we must 'fake' consumption of the data in order to ensure
1827 * that window updates are sent back. Otherwise the connection might
1830 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
1832 c->local_window -= data_len;
1833 c->local_consumed += data_len;
1840 if (data_len > c->local_maxpacket) {
1841 logit("channel %d: rcvd big packet %d, maxpack %d",
1842 c->self, data_len, c->local_maxpacket);
1844 if (data_len > c->local_window) {
1845 logit("channel %d: rcvd too much data %d, win %d",
1846 c->self, data_len, c->local_window);
1850 c->local_window -= data_len;
1853 buffer_append(&c->output, data, data_len);
1858 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
1862 u_int data_len, tcode;
1865 /* Get the channel number and verify it. */
1866 id = packet_get_int();
1867 c = channel_lookup(id);
1870 packet_disconnect("Received extended_data for bad channel %d.", id);
1871 if (c->type != SSH_CHANNEL_OPEN) {
1872 logit("channel %d: ext data for non open", id);
1875 if (c->flags & CHAN_EOF_RCVD) {
1876 if (datafellows & SSH_BUG_EXTEOF)
1877 debug("channel %d: accepting ext data after eof", id);
1879 packet_disconnect("Received extended_data after EOF "
1880 "on channel %d.", id);
1882 tcode = packet_get_int();
1884 c->extended_usage != CHAN_EXTENDED_WRITE ||
1885 tcode != SSH2_EXTENDED_DATA_STDERR) {
1886 logit("channel %d: bad ext data", c->self);
1889 data = packet_get_string(&data_len);
1891 if (data_len > c->local_window) {
1892 logit("channel %d: rcvd too much extended_data %d, win %d",
1893 c->self, data_len, c->local_window);
1897 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1898 c->local_window -= data_len;
1899 buffer_append(&c->extended, data, data_len);
1904 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
1909 id = packet_get_int();
1911 c = channel_lookup(id);
1913 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1916 /* XXX force input close */
1917 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
1918 debug("channel %d: FORCE input drain", c->self);
1919 c->istate = CHAN_INPUT_WAIT_DRAIN;
1920 if (buffer_len(&c->input) == 0)
1927 channel_input_close(int type, u_int32_t seq, void *ctxt)
1932 id = packet_get_int();
1934 c = channel_lookup(id);
1936 packet_disconnect("Received close for nonexistent channel %d.", id);
1939 * Send a confirmation that we have closed the channel and no more
1940 * data is coming for it.
1942 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1943 packet_put_int(c->remote_id);
1947 * If the channel is in closed state, we have sent a close request,
1948 * and the other side will eventually respond with a confirmation.
1949 * Thus, we cannot free the channel here, because then there would be
1950 * no-one to receive the confirmation. The channel gets freed when
1951 * the confirmation arrives.
1953 if (c->type != SSH_CHANNEL_CLOSED) {
1955 * Not a closed channel - mark it as draining, which will
1956 * cause it to be freed later.
1958 buffer_clear(&c->input);
1959 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1963 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1965 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
1967 int id = packet_get_int();
1968 Channel *c = channel_lookup(id);
1972 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1973 chan_rcvd_oclose(c);
1977 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
1979 int id = packet_get_int();
1980 Channel *c = channel_lookup(id);
1984 packet_disconnect("Received close confirmation for "
1985 "out-of-range channel %d.", id);
1986 if (c->type != SSH_CHANNEL_CLOSED)
1987 packet_disconnect("Received close confirmation for "
1988 "non-closed channel %d (type %d).", id, c->type);
1993 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
1998 id = packet_get_int();
1999 c = channel_lookup(id);
2001 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2002 packet_disconnect("Received open confirmation for "
2003 "non-opening channel %d.", id);
2004 remote_id = packet_get_int();
2005 /* Record the remote channel number and mark that the channel is now open. */
2006 c->remote_id = remote_id;
2007 c->type = SSH_CHANNEL_OPEN;
2010 c->remote_window = packet_get_int();
2011 c->remote_maxpacket = packet_get_int();
2013 debug2("callback start");
2014 c->confirm(c->self, NULL);
2015 debug2("callback done");
2017 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2018 c->remote_window, c->remote_maxpacket);
2024 reason2txt(int reason)
2027 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2028 return "administratively prohibited";
2029 case SSH2_OPEN_CONNECT_FAILED:
2030 return "connect failed";
2031 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2032 return "unknown channel type";
2033 case SSH2_OPEN_RESOURCE_SHORTAGE:
2034 return "resource shortage";
2036 return "unknown reason";
2040 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2043 char *msg = NULL, *lang = NULL;
2046 id = packet_get_int();
2047 c = channel_lookup(id);
2049 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2050 packet_disconnect("Received open failure for "
2051 "non-opening channel %d.", id);
2053 reason = packet_get_int();
2054 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2055 msg = packet_get_string(NULL);
2056 lang = packet_get_string(NULL);
2058 logit("channel %d: open failed: %s%s%s", id,
2059 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2066 /* Free the channel. This will also close the socket. */
2071 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2080 /* Get the channel number and verify it. */
2081 id = packet_get_int();
2082 c = channel_lookup(id);
2084 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
2085 logit("Received window adjust for "
2086 "non-open channel %d.", id);
2089 adjust = packet_get_int();
2091 debug2("channel %d: rcvd adjust %u", id, adjust);
2092 c->remote_window += adjust;
2096 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2100 char *host, *originator_string;
2101 int remote_id, sock = -1;
2103 remote_id = packet_get_int();
2104 host = packet_get_string(NULL);
2105 host_port = packet_get_int();
2107 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2108 originator_string = packet_get_string(NULL);
2110 originator_string = xstrdup("unknown (remote did not supply name)");
2113 sock = channel_connect_to(host, host_port);
2115 c = channel_new("connected socket",
2116 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2117 originator_string, 1);
2118 c->remote_id = remote_id;
2120 xfree(originator_string);
2122 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2123 packet_put_int(remote_id);
2130 /* -- tcp forwarding */
2133 channel_set_af(int af)
2139 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
2140 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2143 int success, sock, on = 1;
2144 struct addrinfo hints, *ai, *aitop;
2146 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2149 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2150 listen_addr : host_to_connect;
2153 error("No forward host name.");
2156 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2157 error("Forward host name too long.");
2162 * getaddrinfo returns a loopback address if the hostname is
2163 * set to NULL and hints.ai_flags is not AI_PASSIVE
2165 memset(&hints, 0, sizeof(hints));
2166 hints.ai_family = IPv4or6;
2167 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2168 hints.ai_socktype = SOCK_STREAM;
2169 snprintf(strport, sizeof strport, "%d", listen_port);
2170 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2171 packet_disconnect("getaddrinfo: fatal error");
2173 for (ai = aitop; ai; ai = ai->ai_next) {
2174 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2176 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2177 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2178 error("channel_setup_fwd_listener: getnameinfo failed");
2181 /* Create a port to listen for the host. */
2182 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2184 /* this is no error since kernel may not support ipv6 */
2185 verbose("socket: %.100s", strerror(errno));
2189 * Set socket options.
2190 * Allow local port reuse in TIME_WAIT.
2192 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on,
2194 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
2196 debug("Local forwarding listening on %s port %s.", ntop, strport);
2198 /* Bind the socket to the address. */
2199 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2200 /* address can be in use ipv6 address is already bound */
2202 error("bind: %.100s", strerror(errno));
2204 verbose("bind: %.100s", strerror(errno));
2209 /* Start listening for connections on the socket. */
2210 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2211 error("listen: %.100s", strerror(errno));
2215 /* Allocate a channel number for the socket. */
2216 c = channel_new("port listener", type, sock, sock, -1,
2217 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2218 0, "port listener", 1);
2219 strlcpy(c->path, host, sizeof(c->path));
2220 c->host_port = port_to_connect;
2221 c->listening_port = listen_port;
2225 error("channel_setup_fwd_listener: cannot listen to port: %d",
2227 freeaddrinfo(aitop);
2231 /* protocol local port fwd, used by ssh (and sshd in v1) */
2233 channel_setup_local_fwd_listener(u_short listen_port,
2234 const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2236 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2237 NULL, listen_port, host_to_connect, port_to_connect, gateway_ports);
2240 /* protocol v2 remote port fwd, used by sshd */
2242 channel_setup_remote_fwd_listener(const char *listen_address,
2243 u_short listen_port, int gateway_ports)
2245 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2246 listen_address, listen_port, NULL, 0, gateway_ports);
2250 * Initiate forwarding of connections to port "port" on remote host through
2251 * the secure channel to host:port from local side.
2255 channel_request_remote_forwarding(u_short listen_port,
2256 const char *host_to_connect, u_short port_to_connect)
2258 int type, success = 0;
2260 /* Record locally that connection to this host/port is permitted. */
2261 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2262 fatal("channel_request_remote_forwarding: too many forwards");
2264 /* Send the forward request to the remote side. */
2266 const char *address_to_bind = "0.0.0.0";
2267 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2268 packet_put_cstring("tcpip-forward");
2269 packet_put_char(1); /* boolean: want reply */
2270 packet_put_cstring(address_to_bind);
2271 packet_put_int(listen_port);
2273 packet_write_wait();
2274 /* Assume that server accepts the request */
2277 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2278 packet_put_int(listen_port);
2279 packet_put_cstring(host_to_connect);
2280 packet_put_int(port_to_connect);
2282 packet_write_wait();
2284 /* Wait for response from the remote side. */
2285 type = packet_read();
2287 case SSH_SMSG_SUCCESS:
2290 case SSH_SMSG_FAILURE:
2291 logit("Warning: Server denied remote port forwarding.");
2294 /* Unknown packet */
2295 packet_disconnect("Protocol error for port forward request:"
2296 "received packet type %d.", type);
2300 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2301 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2302 permitted_opens[num_permitted_opens].listen_port = listen_port;
2303 num_permitted_opens++;
2308 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2309 * listening for the port, and sends back a success reply (or disconnect
2310 * message if there was an error). This never returns if there was an error.
2314 channel_input_port_forward_request(int is_root, int gateway_ports)
2316 u_short port, host_port;
2319 /* Get arguments from the packet. */
2320 port = packet_get_int();
2321 hostname = packet_get_string(NULL);
2322 host_port = packet_get_int();
2326 * Check that an unprivileged user is not trying to forward a
2329 if (port < IPPORT_RESERVED && !is_root)
2331 "Requested forwarding of port %d but user is not root.",
2334 packet_disconnect("Dynamic forwarding denied.");
2337 /* Initiate forwarding */
2338 channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports);
2340 /* Free the argument string. */
2345 * Permits opening to any host/port if permitted_opens[] is empty. This is
2346 * usually called by the server, because the user could connect to any port
2347 * anyway, and the server has no way to know but to trust the client anyway.
2350 channel_permit_all_opens(void)
2352 if (num_permitted_opens == 0)
2353 all_opens_permitted = 1;
2357 channel_add_permitted_opens(char *host, int port)
2359 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2360 fatal("channel_request_remote_forwarding: too many forwards");
2361 debug("allow port forwarding to host %s port %d", host, port);
2363 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2364 permitted_opens[num_permitted_opens].port_to_connect = port;
2365 num_permitted_opens++;
2367 all_opens_permitted = 0;
2371 channel_clear_permitted_opens(void)
2375 for (i = 0; i < num_permitted_opens; i++)
2376 xfree(permitted_opens[i].host_to_connect);
2377 num_permitted_opens = 0;
2382 /* return socket to remote host, port */
2384 connect_to(const char *host, u_short port)
2386 struct addrinfo hints, *ai, *aitop;
2387 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2391 memset(&hints, 0, sizeof(hints));
2392 hints.ai_family = IPv4or6;
2393 hints.ai_socktype = SOCK_STREAM;
2394 snprintf(strport, sizeof strport, "%d", port);
2395 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2396 error("connect_to %.100s: unknown host (%s)", host,
2397 gai_strerror(gaierr));
2400 for (ai = aitop; ai; ai = ai->ai_next) {
2401 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2403 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2404 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2405 error("connect_to: getnameinfo failed");
2408 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2410 if (ai->ai_next == NULL)
2411 error("socket: %.100s", strerror(errno));
2413 verbose("socket: %.100s", strerror(errno));
2416 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2417 fatal("connect_to: F_SETFL: %s", strerror(errno));
2418 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2419 errno != EINPROGRESS) {
2420 error("connect_to %.100s port %s: %.100s", ntop, strport,
2423 continue; /* fail -- try next */
2425 break; /* success */
2428 freeaddrinfo(aitop);
2430 error("connect_to %.100s port %d: failed.", host, port);
2439 channel_connect_by_listen_address(u_short listen_port)
2443 for (i = 0; i < num_permitted_opens; i++)
2444 if (permitted_opens[i].listen_port == listen_port)
2446 permitted_opens[i].host_to_connect,
2447 permitted_opens[i].port_to_connect);
2448 error("WARNING: Server requests forwarding for unknown listen_port %d",
2453 /* Check if connecting to that port is permitted and connect. */
2455 channel_connect_to(const char *host, u_short port)
2459 permit = all_opens_permitted;
2461 for (i = 0; i < num_permitted_opens; i++)
2462 if (permitted_opens[i].port_to_connect == port &&
2463 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2468 logit("Received request to connect to host %.100s port %d, "
2469 "but the request was denied.", host, port);
2472 return connect_to(host, port);
2475 /* -- X11 forwarding */
2478 * Creates an internet domain socket for listening for X11 connections.
2479 * Returns 0 and a suitable display number for the DISPLAY variable
2480 * stored in display_numberp , or -1 if an error occurs.
2483 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
2484 int single_connection, u_int *display_numberp)
2487 int display_number, sock;
2489 struct addrinfo hints, *ai, *aitop;
2490 char strport[NI_MAXSERV];
2491 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2493 for (display_number = x11_display_offset;
2494 display_number < MAX_DISPLAYS;
2496 port = 6000 + display_number;
2497 memset(&hints, 0, sizeof(hints));
2498 hints.ai_family = IPv4or6;
2499 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
2500 hints.ai_socktype = SOCK_STREAM;
2501 snprintf(strport, sizeof strport, "%d", port);
2502 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2503 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2506 for (ai = aitop; ai; ai = ai->ai_next) {
2507 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2509 sock = socket(ai->ai_family, ai->ai_socktype,
2512 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2513 error("socket: %.100s", strerror(errno));
2516 debug("x11_create_display_inet: Socket family %d not supported",
2522 if (ai->ai_family == AF_INET6) {
2524 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
2525 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
2528 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2529 debug2("bind port %d: %.100s", port, strerror(errno));
2535 for (n = 0; n < num_socks; n++) {
2541 socks[num_socks++] = sock;
2542 #ifndef DONT_TRY_OTHER_AF
2543 if (num_socks == NUM_SOCKS)
2546 if (x11_use_localhost) {
2547 if (num_socks == NUM_SOCKS)
2554 freeaddrinfo(aitop);
2558 if (display_number >= MAX_DISPLAYS) {
2559 error("Failed to allocate internet-domain X11 display socket.");
2562 /* Start listening for connections on the socket. */
2563 for (n = 0; n < num_socks; n++) {
2565 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2566 error("listen: %.100s", strerror(errno));
2572 /* Allocate a channel for each socket. */
2573 for (n = 0; n < num_socks; n++) {
2575 nc = channel_new("x11 listener",
2576 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2577 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2578 0, "X11 inet listener", 1);
2579 nc->single_connection = single_connection;
2582 /* Return the display number for the DISPLAY environment variable. */
2583 *display_numberp = display_number;
2588 connect_local_xsocket(u_int dnr)
2591 struct sockaddr_un addr;
2593 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2595 error("socket: %.100s", strerror(errno));
2596 memset(&addr, 0, sizeof(addr));
2597 addr.sun_family = AF_UNIX;
2598 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
2599 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2602 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2607 x11_connect_display(void)
2609 int display_number, sock = 0;
2610 const char *display;
2611 char buf[1024], *cp;
2612 struct addrinfo hints, *ai, *aitop;
2613 char strport[NI_MAXSERV];
2616 /* Try to open a socket for the local X server. */
2617 display = getenv("DISPLAY");
2619 error("DISPLAY not set.");
2623 * Now we decode the value of the DISPLAY variable and make a
2624 * connection to the real X server.
2628 * Check if it is a unix domain socket. Unix domain displays are in
2629 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2631 if (strncmp(display, "unix:", 5) == 0 ||
2632 display[0] == ':') {
2633 /* Connect to the unix domain socket. */
2634 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2635 error("Could not parse display number from DISPLAY: %.100s",
2639 /* Create a socket. */
2640 sock = connect_local_xsocket(display_number);
2644 /* OK, we now have a connection to the display. */
2648 * Connect to an inet socket. The DISPLAY value is supposedly
2649 * hostname:d[.s], where hostname may also be numeric IP address.
2651 strlcpy(buf, display, sizeof(buf));
2652 cp = strchr(buf, ':');
2654 error("Could not find ':' in DISPLAY: %.100s", display);
2658 /* buf now contains the host name. But first we parse the display number. */
2659 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2660 error("Could not parse display number from DISPLAY: %.100s",
2665 /* Look up the host address */
2666 memset(&hints, 0, sizeof(hints));
2667 hints.ai_family = IPv4or6;
2668 hints.ai_socktype = SOCK_STREAM;
2669 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2670 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2671 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2674 for (ai = aitop; ai; ai = ai->ai_next) {
2675 /* Create a socket. */
2676 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2678 debug2("socket: %.100s", strerror(errno));
2681 /* Connect it to the display. */
2682 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2683 debug2("connect %.100s port %d: %.100s", buf,
2684 6000 + display_number, strerror(errno));
2691 freeaddrinfo(aitop);
2693 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2702 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2703 * the remote channel number. We should do whatever we want, and respond
2704 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2708 x11_input_open(int type, u_int32_t seq, void *ctxt)
2711 int remote_id, sock = 0;
2714 debug("Received X11 open request.");
2716 remote_id = packet_get_int();
2718 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2719 remote_host = packet_get_string(NULL);
2721 remote_host = xstrdup("unknown (remote did not supply name)");
2725 /* Obtain a connection to the real X display. */
2726 sock = x11_connect_display();
2728 /* Allocate a channel for this connection. */
2729 c = channel_new("connected x11 socket",
2730 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2732 c->remote_id = remote_id;
2737 /* Send refusal to the remote host. */
2738 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2739 packet_put_int(remote_id);
2741 /* Send a confirmation to the remote host. */
2742 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2743 packet_put_int(remote_id);
2744 packet_put_int(c->self);
2749 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2751 deny_input_open(int type, u_int32_t seq, void *ctxt)
2753 int rchan = packet_get_int();
2756 case SSH_SMSG_AGENT_OPEN:
2757 error("Warning: ssh server tried agent forwarding.");
2759 case SSH_SMSG_X11_OPEN:
2760 error("Warning: ssh server tried X11 forwarding.");
2763 error("deny_input_open: type %d", type);
2766 error("Warning: this is probably a break in attempt by a malicious server.");
2767 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2768 packet_put_int(rchan);
2773 * Requests forwarding of X11 connections, generates fake authentication
2774 * data, and enables authentication spoofing.
2775 * This should be called in the client only.
2778 x11_request_forwarding_with_spoofing(int client_session_id,
2779 const char *proto, const char *data)
2781 u_int data_len = (u_int) strlen(data) / 2;
2782 u_int i, value, len;
2788 cp = getenv("DISPLAY");
2790 cp = strchr(cp, ':');
2792 cp = strchr(cp, '.');
2794 screen_number = atoi(cp + 1);
2798 /* Save protocol name. */
2799 x11_saved_proto = xstrdup(proto);
2802 * Extract real authentication data and generate fake data of the
2805 x11_saved_data = xmalloc(data_len);
2806 x11_fake_data = xmalloc(data_len);
2807 for (i = 0; i < data_len; i++) {
2808 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2809 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2811 rand = arc4random();
2812 x11_saved_data[i] = value;
2813 x11_fake_data[i] = rand & 0xff;
2816 x11_saved_data_len = data_len;
2817 x11_fake_data_len = data_len;
2819 /* Convert the fake data into hex. */
2820 len = 2 * data_len + 1;
2821 new_data = xmalloc(len);
2822 for (i = 0; i < data_len; i++)
2823 snprintf(new_data + 2 * i, len - 2 * i,
2824 "%02x", (u_char) x11_fake_data[i]);
2826 /* Send the request packet. */
2828 channel_request_start(client_session_id, "x11-req", 0);
2829 packet_put_char(0); /* XXX bool single connection */
2831 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2833 packet_put_cstring(proto);
2834 packet_put_cstring(new_data);
2835 packet_put_int(screen_number);
2837 packet_write_wait();
2842 /* -- agent forwarding */
2844 /* Sends a message to the server to request authentication fd forwarding. */
2847 auth_request_forwarding(void)
2849 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2851 packet_write_wait();