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 1.106 2001/04/11 13:56:13 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("channel %d: closing 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);
547 channel_decode_helper(Channel *c, int start, int lookfor)
552 p = buffer_ptr(&c->input);
553 have = buffer_len(&c->input);
554 debug2("channel %d: decode_helper: start %d have %d lookfor %d",
555 c->self, start, have, lookfor);
558 for (i = start; i < have; i++) {
559 if (p[i] == lookfor) {
560 debug2("channel %d: decode_helper: matched at %d",
562 if (lookfor == '\0' ||
570 /* the peer is probably sending garbage */
571 debug("channel %d: decode_helper: too long",
576 return 0; /* need more */
579 /* try to decode a http connect header */
581 channel_decode_https(Channel *c, fd_set * readset, fd_set * writeset)
583 u_char *p, *host, *buf;
585 char httpok[] = "HTTP/1.0 200\r\n\r\n";
587 debug2("channel %d: decode https connect", c->self);
588 ret = channel_decode_helper(c, strlen("connect "), '\r');
591 p = buffer_ptr(&c->input);
592 buf = xmalloc(ret+1);
596 if (sscanf(buf, "CONNECT %[^:]:%u HTTP/", host, &port) != 2) {
597 debug("channel %d: cannot parse http header", c->self);
600 debug("channel %d: dynamic request: https host %s port %u",
601 c->self, host, port);
602 strlcpy(c->path, host, sizeof(c->path));
606 buffer_consume(&c->input, ret+4);
607 buffer_append(&c->output, httpok, strlen(httpok));
612 /* try to decode a socks4 header */
614 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
623 struct in_addr dest_addr;
626 debug2("channel %d: decode socks4", c->self);
627 ret = channel_decode_helper(c, sizeof(s4_req), '\0');
630 buffer_get(&c->input, (char *)&s4_req.version, 1);
631 buffer_get(&c->input, (char *)&s4_req.command, 1);
632 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
633 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
634 p = buffer_ptr(&c->input);
636 have = buffer_len(&c->input);
637 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
639 fatal("channel %d: decode socks4: len %d > have %d",
641 strlcpy(username, p, sizeof(username));
642 buffer_consume(&c->input, len);
643 buffer_consume(&c->input, 1); /* trailing '\0' */
645 host = inet_ntoa(s4_req.dest_addr);
646 strlcpy(c->path, host, sizeof(c->path));
647 c->host_port = ntohs(s4_req.dest_port);
649 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
650 c->self, host, c->host_port, s4_req.command);
652 if (s4_req.command != 1) {
653 debug("channel %d: cannot handle: socks4 cn %d",
654 c->self, s4_req.command);
657 s4_rsp.version = 0; /* vn: 0 for reply */
658 s4_rsp.command = 90; /* cd: req granted */
659 s4_rsp.dest_port = 0; /* ignored */
660 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
661 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
665 /* try to decode a socks5 header */
666 #define SSH_SOCKS5_AUTHDONE 0x1000
667 #define SSH_SOCKS5_NOAUTH 0x00
668 #define SSH_SOCKS5_IPV4 0x01
669 #define SSH_SOCKS5_DOMAIN 0x03
670 #define SSH_SOCKS5_IPV6 0x04
671 #define SSH_SOCKS5_CONNECT 0x01
672 #define SSH_SOCKS5_SUCCESS 0x00
675 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset)
684 u_char *p, dest_addr[255+1];
685 int i, have, found, nmethods, addrlen, af;
687 debug2("channel %d: decode socks5", c->self);
688 p = buffer_ptr(&c->input);
691 have = buffer_len(&c->input);
692 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
693 /* format: ver | nmethods | methods */
697 if (have < nmethods + 2)
699 /* look for method: "NO AUTHENTICATION REQUIRED" */
700 for (found = 0, i = 2 ; i < nmethods + 2; i++) {
701 if (p[i] == SSH_SOCKS5_NOAUTH ) {
707 debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
711 buffer_consume(&c->input, nmethods + 2);
712 buffer_put_char(&c->output, 0x05); /* version */
713 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
714 FD_SET(c->sock, writeset);
715 c->flags |= SSH_SOCKS5_AUTHDONE;
716 debug2("channel %d: socks5 auth done", c->self);
717 return 0; /* need more */
719 debug2("channel %d: socks5 post auth", c->self);
720 if (have < sizeof(s5_req)+1)
721 return 0; /* need more */
722 memcpy((char *)&s5_req, p, sizeof(s5_req));
723 if (s5_req.version != 0x05 ||
724 s5_req.command != SSH_SOCKS5_CONNECT ||
725 s5_req.reserved != 0x00) {
726 debug("channel %d: only socks5 connect supported", c->self);
730 case SSH_SOCKS5_IPV4:
734 case SSH_SOCKS5_DOMAIN:
735 addrlen = p[sizeof(s5_req)];
738 case SSH_SOCKS5_IPV6:
743 debug("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
746 if (have < 4 + addrlen + 2)
748 buffer_consume(&c->input, sizeof(s5_req));
749 buffer_get(&c->input, (char *)&dest_addr, addrlen);
750 buffer_get(&c->input, (char *)&dest_port, 2);
751 dest_addr[addrlen] = '\0';
752 if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
753 strlcpy(c->path, dest_addr, sizeof(c->path));
754 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL)
756 c->host_port = ntohs(dest_port);
758 debug("channel %d: dynamic request: socks5 host %s port %u command %u",
759 c->self, c->path, c->host_port, s5_req.command);
761 s5_rsp.version = 0x05;
762 s5_rsp.command = SSH_SOCKS5_SUCCESS;
763 s5_rsp.reserved = 0; /* ignored */
764 s5_rsp.atyp = SSH_SOCKS5_IPV4;
765 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
766 dest_port = 0; /* ignored */
768 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp));
769 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr));
770 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port));
774 /* dynamic port forwarding */
776 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
781 have = buffer_len(&c->input);
783 debug2("channel %d: pre_dynamic: have %d", c->self, have);
784 /* buffer_dump(&c->input); */
785 /* check if the fixed size part of the packet is in buffer. */
788 FD_SET(c->sock, readset);
791 /* try to guess the protocol */
792 p = buffer_ptr(&c->input);
795 ret = channel_decode_https(c, readset, writeset);
798 ret = channel_decode_socks4(c, readset, writeset);
801 ret = channel_decode_socks5(c, readset, writeset);
808 channel_free(c->self);
809 } else if (ret == 0) {
810 debug2("channel %d: pre_dynamic: need more", c->self);
812 FD_SET(c->sock, readset);
814 /* switch to the next state */
815 c->type = SSH_CHANNEL_OPENING;
816 port_open_helper(c, "direct-tcpip");
820 /* This is our fake X11 server socket. */
822 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
824 struct sockaddr addr;
827 char buf[16384], *remote_ipaddr;
830 if (FD_ISSET(c->sock, readset)) {
831 debug("X11 connection requested.");
832 addrlen = sizeof(addr);
833 newsock = accept(c->sock, &addr, &addrlen);
835 error("accept: %.100s", strerror(errno));
838 remote_ipaddr = get_peer_ipaddr(newsock);
839 remote_port = get_peer_port(newsock);
840 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
841 remote_ipaddr, remote_port);
843 newch = channel_new("x11",
844 SSH_CHANNEL_OPENING, newsock, newsock, -1,
845 c->local_window_max, c->local_maxpacket,
848 packet_start(SSH2_MSG_CHANNEL_OPEN);
849 packet_put_cstring("x11");
850 packet_put_int(newch);
851 packet_put_int(c->local_window_max);
852 packet_put_int(c->local_maxpacket);
853 /* originator ipaddr and port */
854 packet_put_cstring(remote_ipaddr);
855 if (datafellows & SSH_BUG_X11FWD) {
856 debug("ssh2 x11 bug compat mode");
858 packet_put_int(remote_port);
862 packet_start(SSH_SMSG_X11_OPEN);
863 packet_put_int(newch);
864 if (have_hostname_in_open)
865 packet_put_string(buf, strlen(buf));
868 xfree(remote_ipaddr);
873 port_open_helper(Channel *c, char *rtype)
877 char *remote_ipaddr = get_peer_ipaddr(c->sock);
878 u_short remote_port = get_peer_port(c->sock);
880 direct = (strcmp(rtype, "direct-tcpip") == 0);
882 snprintf(buf, sizeof buf,
883 "%s: listening port %d for %.100s port %d, "
884 "connect from %.200s port %d",
885 rtype, c->listening_port, c->path, c->host_port,
886 remote_ipaddr, remote_port);
888 xfree(c->remote_name);
889 c->remote_name = xstrdup(buf);
892 packet_start(SSH2_MSG_CHANNEL_OPEN);
893 packet_put_cstring(rtype);
894 packet_put_int(c->self);
895 packet_put_int(c->local_window_max);
896 packet_put_int(c->local_maxpacket);
898 /* target host, port */
899 packet_put_cstring(c->path);
900 packet_put_int(c->host_port);
902 /* listen address, port */
903 packet_put_cstring(c->path);
904 packet_put_int(c->listening_port);
906 /* originator host and port */
907 packet_put_cstring(remote_ipaddr);
908 packet_put_int(remote_port);
911 packet_start(SSH_MSG_PORT_OPEN);
912 packet_put_int(c->self);
913 packet_put_cstring(c->path);
914 packet_put_int(c->host_port);
915 if (have_hostname_in_open)
916 packet_put_cstring(c->remote_name);
919 xfree(remote_ipaddr);
923 * This socket is listening for connections to a forwarded TCP/IP port.
926 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
929 struct sockaddr addr;
930 int newsock, newch, nextstate;
934 if (FD_ISSET(c->sock, readset)) {
935 debug("Connection to port %d forwarding "
936 "to %.100s port %d requested.",
937 c->listening_port, c->path, c->host_port);
939 rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
940 "forwarded-tcpip" : "direct-tcpip";
941 nextstate = (c->host_port == 0) ? SSH_CHANNEL_DYNAMIC :
944 addrlen = sizeof(addr);
945 newsock = accept(c->sock, &addr, &addrlen);
947 error("accept: %.100s", strerror(errno));
950 newch = channel_new(rtype,
951 nextstate, newsock, newsock, -1,
952 c->local_window_max, c->local_maxpacket,
953 0, xstrdup(rtype), 1);
955 nc = channel_lookup(newch);
957 error("xxx: no new channel:");
960 nc->listening_port = c->listening_port;
961 nc->host_port = c->host_port;
962 strlcpy(nc->path, c->path, sizeof(nc->path));
964 if (nextstate != SSH_CHANNEL_DYNAMIC)
965 port_open_helper(nc, rtype);
970 * This is the authentication agent socket listening for connections from
974 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
976 struct sockaddr addr;
980 if (FD_ISSET(c->sock, readset)) {
981 addrlen = sizeof(addr);
982 newsock = accept(c->sock, &addr, &addrlen);
984 error("accept from auth socket: %.100s", strerror(errno));
987 newch = channel_new("accepted auth socket",
988 SSH_CHANNEL_OPENING, newsock, newsock, -1,
989 c->local_window_max, c->local_maxpacket,
990 0, xstrdup("accepted auth socket"), 1);
992 packet_start(SSH2_MSG_CHANNEL_OPEN);
993 packet_put_cstring("auth-agent@openssh.com");
994 packet_put_int(newch);
995 packet_put_int(c->local_window_max);
996 packet_put_int(c->local_maxpacket);
998 packet_start(SSH_SMSG_AGENT_OPEN);
999 packet_put_int(newch);
1006 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1008 if (FD_ISSET(c->sock, writeset)) {
1010 int sz = sizeof(err);
1011 c->type = SSH_CHANNEL_OPEN;
1012 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err, &sz) < 0) {
1013 debug("getsockopt SO_ERROR failed");
1016 debug("channel %d: connected)", c->self);
1018 debug("channel %d: not connected: %s",
1019 c->self, strerror(err));
1020 chan_read_failed(c);
1021 chan_write_failed(c);
1028 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1034 FD_ISSET(c->rfd, readset)) {
1035 len = read(c->rfd, buf, sizeof(buf));
1036 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1039 debug("channel %d: read<=0 rfd %d len %d",
1040 c->self, c->rfd, len);
1041 if (c->type != SSH_CHANNEL_OPEN) {
1042 debug("channel %d: not open", c->self);
1043 channel_free(c->self);
1045 } else if (compat13) {
1046 buffer_consume(&c->output, buffer_len(&c->output));
1047 c->type = SSH_CHANNEL_INPUT_DRAINING;
1048 debug("channel %d: status set to input draining.", c->self);
1050 chan_read_failed(c);
1054 if(c->input_filter != NULL) {
1055 if (c->input_filter(c, buf, len) == -1) {
1056 debug("channel %d: filter stops", c->self);
1057 chan_read_failed(c);
1060 buffer_append(&c->input, buf, len);
1066 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1071 /* Send buffered output data to the socket. */
1073 FD_ISSET(c->wfd, writeset) &&
1074 buffer_len(&c->output) > 0) {
1075 len = write(c->wfd, buffer_ptr(&c->output),
1076 buffer_len(&c->output));
1077 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1080 if (c->type != SSH_CHANNEL_OPEN) {
1081 debug("channel %d: not open", c->self);
1082 channel_free(c->self);
1084 } else if (compat13) {
1085 buffer_consume(&c->output, buffer_len(&c->output));
1086 debug("channel %d: status set to input draining.", c->self);
1087 c->type = SSH_CHANNEL_INPUT_DRAINING;
1089 chan_write_failed(c);
1093 if (compat20 && c->isatty) {
1094 if (tcgetattr(c->wfd, &tio) == 0 &&
1095 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1097 * Simulate echo to reduce the impact of
1098 * traffic analysis. We need to match the
1099 * size of a SSH2_MSG_CHANNEL_DATA message
1100 * (4 byte channel id + data)
1102 packet_send_ignore(4 + len);
1106 buffer_consume(&c->output, len);
1107 if (compat20 && len > 0) {
1108 c->local_consumed += len;
1114 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1119 /** XXX handle drain efd, too */
1121 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1122 FD_ISSET(c->efd, writeset) &&
1123 buffer_len(&c->extended) > 0) {
1124 len = write(c->efd, buffer_ptr(&c->extended),
1125 buffer_len(&c->extended));
1126 debug2("channel %d: written %d to efd %d",
1127 c->self, len, c->efd);
1128 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1131 debug2("channel %d: closing write-efd %d",
1136 buffer_consume(&c->extended, len);
1137 c->local_consumed += len;
1139 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1140 FD_ISSET(c->efd, readset)) {
1141 len = read(c->efd, buf, sizeof(buf));
1142 debug2("channel %d: read %d from efd %d",
1143 c->self, len, c->efd);
1144 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1147 debug2("channel %d: closing read-efd %d",
1152 buffer_append(&c->extended, buf, len);
1159 channel_check_window(Channel *c)
1161 if (c->type == SSH_CHANNEL_OPEN &&
1162 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1163 c->local_window < c->local_window_max/2 &&
1164 c->local_consumed > 0) {
1165 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1166 packet_put_int(c->remote_id);
1167 packet_put_int(c->local_consumed);
1169 debug2("channel %d: window %d sent adjust %d",
1170 c->self, c->local_window,
1172 c->local_window += c->local_consumed;
1173 c->local_consumed = 0;
1179 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1181 channel_handle_rfd(c, readset, writeset);
1182 channel_handle_wfd(c, readset, writeset);
1186 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1188 channel_handle_rfd(c, readset, writeset);
1189 channel_handle_wfd(c, readset, writeset);
1190 channel_handle_efd(c, readset, writeset);
1192 channel_check_window(c);
1196 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1199 /* Send buffered output data to the socket. */
1200 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1201 len = write(c->sock, buffer_ptr(&c->output),
1202 buffer_len(&c->output));
1204 buffer_consume(&c->output, buffer_len(&c->output));
1206 buffer_consume(&c->output, len);
1211 channel_handler_init_20(void)
1213 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1214 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1215 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1216 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1217 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1218 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1219 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1220 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1222 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1223 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1224 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1225 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1226 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1227 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1228 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1232 channel_handler_init_13(void)
1234 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1235 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1236 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1237 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1238 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1239 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1240 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1241 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1242 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1244 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1245 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1246 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1247 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1248 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1249 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1250 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1254 channel_handler_init_15(void)
1256 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1257 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1258 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1259 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1260 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1261 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1262 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1264 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1265 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1266 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1267 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1268 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1269 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1273 channel_handler_init(void)
1276 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1277 channel_pre[i] = NULL;
1278 channel_post[i] = NULL;
1281 channel_handler_init_20();
1283 channel_handler_init_13();
1285 channel_handler_init_15();
1289 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1291 static int did_init = 0;
1296 channel_handler_init();
1299 for (i = 0; i < channels_alloc; i++) {
1301 if (c->type == SSH_CHANNEL_FREE)
1303 if (ftab[c->type] == NULL)
1305 (*ftab[c->type])(c, readset, writeset);
1306 if (chan_is_dead(c)) {
1308 * we have to remove the fd's from the select mask
1309 * before the channels are free'd and the fd's are
1313 FD_CLR(c->wfd, writeset);
1315 FD_CLR(c->rfd, readset);
1317 if (c->extended_usage == CHAN_EXTENDED_READ)
1318 FD_CLR(c->efd, readset);
1319 if (c->extended_usage == CHAN_EXTENDED_WRITE)
1320 FD_CLR(c->efd, writeset);
1322 channel_free(c->self);
1328 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1334 n = MAX(*maxfdp, channel_max_fd);
1336 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1337 if (*readsetp == NULL || n > *maxfdp) {
1342 *readsetp = xmalloc(sz);
1343 *writesetp = xmalloc(sz);
1346 memset(*readsetp, 0, sz);
1347 memset(*writesetp, 0, sz);
1350 channel_handler(channel_pre, *readsetp, *writesetp);
1354 channel_after_select(fd_set * readset, fd_set * writeset)
1356 channel_handler(channel_post, readset, writeset);
1359 /* If there is data to send to the connection, enqueue some of it now. */
1362 channel_output_poll()
1367 for (i = 0; i < channels_alloc; i++) {
1370 /* We are only interested in channels that can have buffered incoming data. */
1372 if (c->type != SSH_CHANNEL_OPEN &&
1373 c->type != SSH_CHANNEL_INPUT_DRAINING)
1376 if (c->type != SSH_CHANNEL_OPEN)
1380 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1381 /* XXX is this true? */
1382 debug2("channel %d: no data after CLOSE", c->self);
1386 /* Get the amount of buffered data for this channel. */
1387 if ((c->istate == CHAN_INPUT_OPEN ||
1388 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1389 (len = buffer_len(&c->input)) > 0) {
1390 /* Send some data for the other side over the secure connection. */
1392 if (len > c->remote_window)
1393 len = c->remote_window;
1394 if (len > c->remote_maxpacket)
1395 len = c->remote_maxpacket;
1397 if (packet_is_interactive()) {
1401 /* Keep the packets at reasonable size. */
1402 if (len > packet_get_maxsize()/2)
1403 len = packet_get_maxsize()/2;
1407 packet_start(compat20 ?
1408 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1409 packet_put_int(c->remote_id);
1410 packet_put_string(buffer_ptr(&c->input), len);
1412 buffer_consume(&c->input, len);
1413 c->remote_window -= len;
1415 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1417 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1419 * input-buffer is empty and read-socket shutdown:
1420 * tell peer, that we will not send more data: send IEOF
1424 /* Send extended data, i.e. stderr */
1426 c->remote_window > 0 &&
1427 (len = buffer_len(&c->extended)) > 0 &&
1428 c->extended_usage == CHAN_EXTENDED_READ) {
1429 debug2("channel %d: rwin %d elen %d euse %d",
1430 c->self, c->remote_window, buffer_len(&c->extended),
1432 if (len > c->remote_window)
1433 len = c->remote_window;
1434 if (len > c->remote_maxpacket)
1435 len = c->remote_maxpacket;
1436 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1437 packet_put_int(c->remote_id);
1438 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1439 packet_put_string(buffer_ptr(&c->extended), len);
1441 buffer_consume(&c->extended, len);
1442 c->remote_window -= len;
1443 debug2("channel %d: sent ext data %d", c->self, len);
1449 * This is called when a packet of type CHANNEL_DATA has just been received.
1450 * The message type has already been consumed, but channel number and data is
1455 channel_input_data(int type, int plen, void *ctxt)
1462 /* Get the channel number and verify it. */
1463 id = packet_get_int();
1464 c = channel_lookup(id);
1466 packet_disconnect("Received data for nonexistent channel %d.", id);
1468 /* Ignore any data for non-open channels (might happen on close) */
1469 if (c->type != SSH_CHANNEL_OPEN &&
1470 c->type != SSH_CHANNEL_X11_OPEN)
1473 /* same for protocol 1.5 if output end is no longer open */
1474 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1478 data = packet_get_string(&data_len);
1482 if (data_len > c->local_maxpacket) {
1483 log("channel %d: rcvd big packet %d, maxpack %d",
1484 c->self, data_len, c->local_maxpacket);
1486 if (data_len > c->local_window) {
1487 log("channel %d: rcvd too much data %d, win %d",
1488 c->self, data_len, c->local_window);
1492 c->local_window -= data_len;
1494 packet_integrity_check(plen, 4 + 4 + data_len, type);
1496 buffer_append(&c->output, data, data_len);
1500 channel_input_extended_data(int type, int plen, void *ctxt)
1508 /* Get the channel number and verify it. */
1509 id = packet_get_int();
1510 c = channel_lookup(id);
1513 packet_disconnect("Received extended_data for bad channel %d.", id);
1514 if (c->type != SSH_CHANNEL_OPEN) {
1515 log("channel %d: ext data for non open", id);
1518 tcode = packet_get_int();
1520 c->extended_usage != CHAN_EXTENDED_WRITE ||
1521 tcode != SSH2_EXTENDED_DATA_STDERR) {
1522 log("channel %d: bad ext data", c->self);
1525 data = packet_get_string(&data_len);
1527 if (data_len > c->local_window) {
1528 log("channel %d: rcvd too much extended_data %d, win %d",
1529 c->self, data_len, c->local_window);
1533 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1534 c->local_window -= data_len;
1535 buffer_append(&c->extended, data, data_len);
1541 * Returns true if no channel has too much buffered data, and false if one or
1542 * more channel is overfull.
1546 channel_not_very_much_buffered_data()
1551 for (i = 0; i < channels_alloc; i++) {
1553 if (c->type == SSH_CHANNEL_OPEN) {
1554 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
1555 debug("channel %d: big input buffer %d",
1556 c->self, buffer_len(&c->input));
1559 if (buffer_len(&c->output) > packet_get_maxsize()) {
1560 debug("channel %d: big output buffer %d",
1561 c->self, buffer_len(&c->output));
1570 channel_input_ieof(int type, int plen, void *ctxt)
1575 packet_integrity_check(plen, 4, type);
1577 id = packet_get_int();
1578 c = channel_lookup(id);
1580 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1585 channel_input_close(int type, int plen, void *ctxt)
1590 packet_integrity_check(plen, 4, type);
1592 id = packet_get_int();
1593 c = channel_lookup(id);
1595 packet_disconnect("Received close for nonexistent channel %d.", id);
1598 * Send a confirmation that we have closed the channel and no more
1599 * data is coming for it.
1601 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1602 packet_put_int(c->remote_id);
1606 * If the channel is in closed state, we have sent a close request,
1607 * and the other side will eventually respond with a confirmation.
1608 * Thus, we cannot free the channel here, because then there would be
1609 * no-one to receive the confirmation. The channel gets freed when
1610 * the confirmation arrives.
1612 if (c->type != SSH_CHANNEL_CLOSED) {
1614 * Not a closed channel - mark it as draining, which will
1615 * cause it to be freed later.
1617 buffer_consume(&c->input, buffer_len(&c->input));
1618 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1622 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1624 channel_input_oclose(int type, int plen, void *ctxt)
1626 int id = packet_get_int();
1627 Channel *c = channel_lookup(id);
1628 packet_integrity_check(plen, 4, type);
1630 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1631 chan_rcvd_oclose(c);
1635 channel_input_close_confirmation(int type, int plen, void *ctxt)
1637 int id = packet_get_int();
1638 Channel *c = channel_lookup(id);
1642 packet_disconnect("Received close confirmation for "
1643 "out-of-range channel %d.", id);
1644 if (c->type != SSH_CHANNEL_CLOSED)
1645 packet_disconnect("Received close confirmation for "
1646 "non-closed channel %d (type %d).", id, c->type);
1647 channel_free(c->self);
1651 channel_input_open_confirmation(int type, int plen, void *ctxt)
1657 packet_integrity_check(plen, 4 + 4, type);
1659 id = packet_get_int();
1660 c = channel_lookup(id);
1662 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1663 packet_disconnect("Received open confirmation for "
1664 "non-opening channel %d.", id);
1665 remote_id = packet_get_int();
1666 /* Record the remote channel number and mark that the channel is now open. */
1667 c->remote_id = remote_id;
1668 c->type = SSH_CHANNEL_OPEN;
1671 c->remote_window = packet_get_int();
1672 c->remote_maxpacket = packet_get_int();
1674 if (c->cb_fn != NULL && c->cb_event == type) {
1675 debug2("callback start");
1676 c->cb_fn(c->self, c->cb_arg);
1677 debug2("callback done");
1679 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1680 c->remote_window, c->remote_maxpacket);
1685 channel_input_open_failure(int type, int plen, void *ctxt)
1688 char *msg = NULL, *lang = NULL;
1692 packet_integrity_check(plen, 4, type);
1694 id = packet_get_int();
1695 c = channel_lookup(id);
1697 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1698 packet_disconnect("Received open failure for "
1699 "non-opening channel %d.", id);
1701 reason = packet_get_int();
1702 if (packet_remaining() > 0) {
1703 msg = packet_get_string(NULL);
1704 lang = packet_get_string(NULL);
1707 log("channel_open_failure: %d: reason %d %s", id,
1708 reason, msg ? msg : "<no additional info>");
1714 /* Free the channel. This will also close the socket. */
1719 channel_input_channel_request(int type, int plen, void *ctxt)
1724 id = packet_get_int();
1725 c = channel_lookup(id);
1728 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1729 packet_disconnect("Received request for "
1730 "non-open channel %d.", id);
1731 if (c->cb_fn != NULL && c->cb_event == type) {
1732 debug2("callback start");
1733 c->cb_fn(c->self, c->cb_arg);
1734 debug2("callback done");
1736 char *service = packet_get_string(NULL);
1737 debug("channel %d: rcvd request for %s", c->self, service);
1738 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1744 channel_input_window_adjust(int type, int plen, void *ctxt)
1752 /* Get the channel number and verify it. */
1753 id = packet_get_int();
1754 c = channel_lookup(id);
1756 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1757 log("Received window adjust for "
1758 "non-open channel %d.", id);
1761 adjust = packet_get_int();
1763 debug2("channel %d: rcvd adjust %d", id, adjust);
1764 c->remote_window += adjust;
1768 * Stops listening for channels, and removes any unix domain sockets that we
1773 channel_stop_listening()
1776 for (i = 0; i < channels_alloc; i++) {
1777 switch (channels[i].type) {
1778 case SSH_CHANNEL_AUTH_SOCKET:
1779 close(channels[i].sock);
1780 unlink(channels[i].path);
1783 case SSH_CHANNEL_PORT_LISTENER:
1784 case SSH_CHANNEL_RPORT_LISTENER:
1785 case SSH_CHANNEL_X11_LISTENER:
1786 close(channels[i].sock);
1796 * Closes the sockets/fds of all channels. This is used to close extra file
1797 * descriptors after a fork.
1804 for (i = 0; i < channels_alloc; i++)
1805 if (channels[i].type != SSH_CHANNEL_FREE)
1806 channel_close_fds(&channels[i]);
1809 /* Returns true if any channel is still open. */
1812 channel_still_open()
1815 for (i = 0; i < channels_alloc; i++)
1816 switch (channels[i].type) {
1817 case SSH_CHANNEL_FREE:
1818 case SSH_CHANNEL_X11_LISTENER:
1819 case SSH_CHANNEL_PORT_LISTENER:
1820 case SSH_CHANNEL_RPORT_LISTENER:
1821 case SSH_CHANNEL_CLOSED:
1822 case SSH_CHANNEL_AUTH_SOCKET:
1823 case SSH_CHANNEL_DYNAMIC:
1824 case SSH_CHANNEL_CONNECTING: /* XXX ??? */
1826 case SSH_CHANNEL_LARVAL:
1828 fatal("cannot happen: SSH_CHANNEL_LARVAL");
1830 case SSH_CHANNEL_OPENING:
1831 case SSH_CHANNEL_OPEN:
1832 case SSH_CHANNEL_X11_OPEN:
1834 case SSH_CHANNEL_INPUT_DRAINING:
1835 case SSH_CHANNEL_OUTPUT_DRAINING:
1837 fatal("cannot happen: OUT_DRAIN");
1840 fatal("channel_still_open: bad channel type %d", channels[i].type);
1847 * Returns a message describing the currently open forwarded connections,
1848 * suitable for sending to the client. The message contains crlf pairs for
1853 channel_open_message()
1859 buffer_init(&buffer);
1860 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
1861 buffer_append(&buffer, buf, strlen(buf));
1862 for (i = 0; i < channels_alloc; i++) {
1863 Channel *c = &channels[i];
1865 case SSH_CHANNEL_FREE:
1866 case SSH_CHANNEL_X11_LISTENER:
1867 case SSH_CHANNEL_PORT_LISTENER:
1868 case SSH_CHANNEL_RPORT_LISTENER:
1869 case SSH_CHANNEL_CLOSED:
1870 case SSH_CHANNEL_AUTH_SOCKET:
1872 case SSH_CHANNEL_LARVAL:
1873 case SSH_CHANNEL_OPENING:
1874 case SSH_CHANNEL_CONNECTING:
1875 case SSH_CHANNEL_DYNAMIC:
1876 case SSH_CHANNEL_OPEN:
1877 case SSH_CHANNEL_X11_OPEN:
1878 case SSH_CHANNEL_INPUT_DRAINING:
1879 case SSH_CHANNEL_OUTPUT_DRAINING:
1880 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
1881 c->self, c->remote_name,
1882 c->type, c->remote_id,
1883 c->istate, buffer_len(&c->input),
1884 c->ostate, buffer_len(&c->output),
1886 buffer_append(&buffer, buf, strlen(buf));
1889 fatal("channel_open_message: bad channel type %d", c->type);
1893 buffer_append(&buffer, "\0", 1);
1894 cp = xstrdup(buffer_ptr(&buffer));
1895 buffer_free(&buffer);
1900 * Initiate forwarding of connections to local port "port" through the secure
1901 * channel to host:port from remote side.
1904 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
1905 u_short port_to_connect, int gateway_ports)
1907 return channel_request_forwarding(
1909 host_to_connect, port_to_connect,
1910 gateway_ports, /*remote_fwd*/ 0);
1914 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
1915 * (SSH_CHANNEL_RPORT_LISTENER).
1918 channel_request_forwarding(
1919 const char *listen_address, u_short listen_port,
1920 const char *host_to_connect, u_short port_to_connect,
1921 int gateway_ports, int remote_fwd)
1923 int success, ch, sock, on = 1, ctype;
1924 struct addrinfo hints, *ai, *aitop;
1925 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1927 struct linger linger;
1932 host = listen_address;
1933 ctype = SSH_CHANNEL_RPORT_LISTENER;
1935 host = host_to_connect;
1936 ctype =SSH_CHANNEL_PORT_LISTENER;
1939 if (strlen(host) > sizeof(channels[0].path) - 1) {
1940 error("Forward host name too long.");
1944 /* XXX listen_address is currently ignored */
1946 * getaddrinfo returns a loopback address if the hostname is
1947 * set to NULL and hints.ai_flags is not AI_PASSIVE
1949 memset(&hints, 0, sizeof(hints));
1950 hints.ai_family = IPv4or6;
1951 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
1952 hints.ai_socktype = SOCK_STREAM;
1953 snprintf(strport, sizeof strport, "%d", listen_port);
1954 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
1955 packet_disconnect("getaddrinfo: fatal error");
1957 for (ai = aitop; ai; ai = ai->ai_next) {
1958 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1960 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
1961 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1962 error("channel_request_forwarding: getnameinfo failed");
1965 /* Create a port to listen for the host. */
1966 sock = socket(ai->ai_family, SOCK_STREAM, 0);
1968 /* this is no error since kernel may not support ipv6 */
1969 verbose("socket: %.100s", strerror(errno));
1973 * Set socket options. We would like the socket to disappear
1974 * as soon as it has been closed for whatever reason.
1976 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
1978 linger.l_linger = 5;
1979 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
1980 debug("Local forwarding listening on %s port %s.", ntop, strport);
1982 /* Bind the socket to the address. */
1983 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1984 /* address can be in use ipv6 address is already bound */
1986 error("bind: %.100s", strerror(errno));
1988 verbose("bind: %.100s", strerror(errno));
1993 /* Start listening for connections on the socket. */
1994 if (listen(sock, 5) < 0) {
1995 error("listen: %.100s", strerror(errno));
1999 /* Allocate a channel number for the socket. */
2000 ch = channel_new("port listener", ctype, sock, sock, -1,
2001 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2002 0, xstrdup("port listener"), 1);
2003 strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
2004 channels[ch].host_port = port_to_connect;
2005 channels[ch].listening_port = listen_port;
2009 error("channel_request_forwarding: cannot listen to port: %d",
2011 freeaddrinfo(aitop);
2016 * Initiate forwarding of connections to port "port" on remote host through
2017 * the secure channel to host:port from local side.
2021 channel_request_remote_forwarding(u_short listen_port,
2022 const char *host_to_connect, u_short port_to_connect)
2024 int payload_len, type, success = 0;
2026 /* Record locally that connection to this host/port is permitted. */
2027 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2028 fatal("channel_request_remote_forwarding: too many forwards");
2030 /* Send the forward request to the remote side. */
2032 const char *address_to_bind = "0.0.0.0";
2033 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2034 packet_put_cstring("tcpip-forward");
2035 packet_put_char(0); /* boolean: want reply */
2036 packet_put_cstring(address_to_bind);
2037 packet_put_int(listen_port);
2039 packet_write_wait();
2040 /* Assume that server accepts the request */
2043 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2044 packet_put_int(listen_port);
2045 packet_put_cstring(host_to_connect);
2046 packet_put_int(port_to_connect);
2048 packet_write_wait();
2050 /* Wait for response from the remote side. */
2051 type = packet_read(&payload_len);
2053 case SSH_SMSG_SUCCESS:
2056 case SSH_SMSG_FAILURE:
2057 log("Warning: Server denied remote port forwarding.");
2060 /* Unknown packet */
2061 packet_disconnect("Protocol error for port forward request:"
2062 "received packet type %d.", type);
2066 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2067 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2068 permitted_opens[num_permitted_opens].listen_port = listen_port;
2069 num_permitted_opens++;
2074 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2075 * listening for the port, and sends back a success reply (or disconnect
2076 * message if there was an error). This never returns if there was an error.
2080 channel_input_port_forward_request(int is_root, int gateway_ports)
2082 u_short port, host_port;
2085 /* Get arguments from the packet. */
2086 port = packet_get_int();
2087 hostname = packet_get_string(NULL);
2088 host_port = packet_get_int();
2092 * Check that an unprivileged user is not trying to forward a
2095 if (port < IPPORT_RESERVED && !is_root)
2096 packet_disconnect("Requested forwarding of port %d but user is not root.",
2099 /* Initiate forwarding */
2100 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2102 /* Free the argument string. */
2107 * Permits opening to any host/port if permitted_opens[] is empty. This is
2108 * usually called by the server, because the user could connect to any port
2109 * anyway, and the server has no way to know but to trust the client anyway.
2112 channel_permit_all_opens()
2114 if (num_permitted_opens == 0)
2115 all_opens_permitted = 1;
2119 channel_add_permitted_opens(char *host, int port)
2121 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2122 fatal("channel_request_remote_forwarding: too many forwards");
2123 debug("allow port forwarding to host %s port %d", host, port);
2125 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2126 permitted_opens[num_permitted_opens].port_to_connect = port;
2127 num_permitted_opens++;
2129 all_opens_permitted = 0;
2133 channel_clear_permitted_opens(void)
2137 for (i = 0; i < num_permitted_opens; i++)
2138 xfree(permitted_opens[i].host_to_connect);
2139 num_permitted_opens = 0;
2144 /* return socket to remote host, port */
2146 connect_to(const char *host, u_short port)
2148 struct addrinfo hints, *ai, *aitop;
2149 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2153 memset(&hints, 0, sizeof(hints));
2154 hints.ai_family = IPv4or6;
2155 hints.ai_socktype = SOCK_STREAM;
2156 snprintf(strport, sizeof strport, "%d", port);
2157 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2158 error("connect_to %.100s: unknown host (%s)", host,
2159 gai_strerror(gaierr));
2162 for (ai = aitop; ai; ai = ai->ai_next) {
2163 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2165 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2166 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2167 error("connect_to: getnameinfo failed");
2170 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2172 error("socket: %.100s", strerror(errno));
2175 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2176 fatal("connect_to: F_SETFL: %s", strerror(errno));
2177 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2178 errno != EINPROGRESS) {
2179 error("connect_to %.100s port %s: %.100s", ntop, strport,
2182 continue; /* fail -- try next */
2184 break; /* success */
2187 freeaddrinfo(aitop);
2189 error("connect_to %.100s port %d: failed.", host, port);
2197 channel_connect_by_listen_adress(u_short listen_port)
2201 for (i = 0; i < num_permitted_opens; i++)
2202 if (permitted_opens[i].listen_port == listen_port)
2204 permitted_opens[i].host_to_connect,
2205 permitted_opens[i].port_to_connect);
2206 error("WARNING: Server requests forwarding for unknown listen_port %d",
2211 /* Check if connecting to that port is permitted and connect. */
2213 channel_connect_to(const char *host, u_short port)
2217 permit = all_opens_permitted;
2219 for (i = 0; i < num_permitted_opens; i++)
2220 if (permitted_opens[i].port_to_connect == port &&
2221 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2226 log("Received request to connect to host %.100s port %d, "
2227 "but the request was denied.", host, port);
2230 return connect_to(host, port);
2234 * This is called after receiving PORT_OPEN message. This attempts to
2235 * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
2236 * or CHANNEL_OPEN_FAILURE.
2240 channel_input_port_open(int type, int plen, void *ctxt)
2243 char *host, *originator_string;
2244 int remote_channel, sock = -1, newch;
2246 remote_channel = packet_get_int();
2247 host = packet_get_string(NULL);
2248 host_port = packet_get_int();
2250 if (have_hostname_in_open) {
2251 originator_string = packet_get_string(NULL);
2253 originator_string = xstrdup("unknown (remote did not supply name)");
2256 sock = channel_connect_to(host, host_port);
2258 newch = channel_allocate(SSH_CHANNEL_CONNECTING,
2259 sock, originator_string);
2260 channels[newch].remote_id = remote_channel;
2262 /*XXX delay answer? */
2263 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2264 packet_put_int(remote_channel);
2265 packet_put_int(newch);
2268 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2269 packet_put_int(remote_channel);
2276 * Creates an internet domain socket for listening for X11 connections.
2277 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2281 #define NUM_SOCKS 10
2284 x11_create_display_inet(int screen_number, int x11_display_offset)
2286 int display_number, sock;
2288 struct addrinfo hints, *ai, *aitop;
2289 char strport[NI_MAXSERV];
2290 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2292 char hostname[MAXHOSTNAMELEN];
2294 for (display_number = x11_display_offset;
2295 display_number < MAX_DISPLAYS;
2297 port = 6000 + display_number;
2298 memset(&hints, 0, sizeof(hints));
2299 hints.ai_family = IPv4or6;
2300 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2301 hints.ai_socktype = SOCK_STREAM;
2302 snprintf(strport, sizeof strport, "%d", port);
2303 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2304 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2307 for (ai = aitop; ai; ai = ai->ai_next) {
2308 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2310 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2312 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2313 error("socket: %.100s", strerror(errno));
2316 debug("x11_create_display_inet: Socket family %d not supported",
2321 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2322 debug("bind port %d: %.100s", port, strerror(errno));
2323 shutdown(sock, SHUT_RDWR);
2329 for (n = 0; n < num_socks; n++) {
2330 shutdown(socks[n], SHUT_RDWR);
2336 socks[num_socks++] = sock;
2337 #ifndef DONT_TRY_OTHER_AF
2338 if (num_socks == NUM_SOCKS)
2344 freeaddrinfo(aitop);
2348 if (display_number >= MAX_DISPLAYS) {
2349 error("Failed to allocate internet-domain X11 display socket.");
2352 /* Start listening for connections on the socket. */
2353 for (n = 0; n < num_socks; n++) {
2355 if (listen(sock, 5) < 0) {
2356 error("listen: %.100s", strerror(errno));
2357 shutdown(sock, SHUT_RDWR);
2363 /* Set up a suitable value for the DISPLAY variable. */
2364 if (gethostname(hostname, sizeof(hostname)) < 0)
2365 fatal("gethostname: %.100s", strerror(errno));
2367 #ifdef IPADDR_IN_DISPLAY
2369 * HPUX detects the local hostname in the DISPLAY variable and tries
2370 * to set up a shared memory connection to the server, which it
2371 * incorrectly supposes to be local.
2373 * The workaround - as used in later $$H and other programs - is
2374 * is to set display to the host's IP address.
2378 struct in_addr my_addr;
2380 he = gethostbyname(hostname);
2382 error("[X11-broken-fwd-hostname-workaround] Could not get "
2383 "IP address for hostname %s.", hostname);
2385 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2386 "Could not get IP address for hostname %s.", hostname);
2388 shutdown(sock, SHUT_RDWR);
2394 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2396 /* Set DISPLAY to <ip address>:screen.display */
2397 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2398 display_number, screen_number);
2400 #else /* IPADDR_IN_DISPLAY */
2401 /* Just set DISPLAY to hostname:screen.display */
2402 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2403 display_number, screen_number);
2404 #endif /* IPADDR_IN_DISPLAY */
2406 /* Allocate a channel for each socket. */
2407 for (n = 0; n < num_socks; n++) {
2409 (void) channel_new("x11 listener",
2410 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2411 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2412 0, xstrdup("X11 inet listener"), 1);
2415 /* Return a suitable value for the DISPLAY environment variable. */
2416 return xstrdup(display);
2420 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2425 connect_local_xsocket(u_int dnr)
2427 static const char *const x_sockets[] = {
2429 "/var/X/.X11-unix/X" "%u",
2430 "/usr/spool/sockets/X11/" "%u",
2434 struct sockaddr_un addr;
2435 const char *const * path;
2437 for (path = x_sockets; *path; ++path) {
2438 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2440 error("socket: %.100s", strerror(errno));
2441 memset(&addr, 0, sizeof(addr));
2442 addr.sun_family = AF_UNIX;
2443 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2444 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2448 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2453 x11_connect_display(void)
2455 int display_number, sock = 0;
2456 const char *display;
2457 char buf[1024], *cp;
2458 struct addrinfo hints, *ai, *aitop;
2459 char strport[NI_MAXSERV];
2462 /* Try to open a socket for the local X server. */
2463 display = getenv("DISPLAY");
2465 error("DISPLAY not set.");
2469 * Now we decode the value of the DISPLAY variable and make a
2470 * connection to the real X server.
2474 * Check if it is a unix domain socket. Unix domain displays are in
2475 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2477 if (strncmp(display, "unix:", 5) == 0 ||
2478 display[0] == ':') {
2479 /* Connect to the unix domain socket. */
2480 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2481 error("Could not parse display number from DISPLAY: %.100s",
2485 /* Create a socket. */
2486 sock = connect_local_xsocket(display_number);
2490 /* OK, we now have a connection to the display. */
2494 * Connect to an inet socket. The DISPLAY value is supposedly
2495 * hostname:d[.s], where hostname may also be numeric IP address.
2497 strncpy(buf, display, sizeof(buf));
2498 buf[sizeof(buf) - 1] = 0;
2499 cp = strchr(buf, ':');
2501 error("Could not find ':' in DISPLAY: %.100s", display);
2505 /* buf now contains the host name. But first we parse the display number. */
2506 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2507 error("Could not parse display number from DISPLAY: %.100s",
2512 /* Look up the host address */
2513 memset(&hints, 0, sizeof(hints));
2514 hints.ai_family = IPv4or6;
2515 hints.ai_socktype = SOCK_STREAM;
2516 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2517 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2518 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2521 for (ai = aitop; ai; ai = ai->ai_next) {
2522 /* Create a socket. */
2523 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2525 debug("socket: %.100s", strerror(errno));
2528 /* Connect it to the display. */
2529 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2530 debug("connect %.100s port %d: %.100s", buf,
2531 6000 + display_number, strerror(errno));
2538 freeaddrinfo(aitop);
2540 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2548 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2549 * the remote channel number. We should do whatever we want, and respond
2550 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2554 x11_input_open(int type, int plen, void *ctxt)
2556 int remote_channel, sock = 0, newch;
2560 /* Get remote channel number. */
2561 remote_channel = packet_get_int();
2563 /* Get remote originator name. */
2564 if (have_hostname_in_open) {
2565 remote_host = packet_get_string(&remote_len);
2568 remote_host = xstrdup("unknown (remote did not supply name)");
2572 debug("Received X11 open request.");
2573 packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN);
2575 /* Obtain a connection to the real X display. */
2576 sock = x11_connect_display();
2578 /* Send refusal to the remote host. */
2579 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2580 packet_put_int(remote_channel);
2583 /* Allocate a channel for this connection. */
2584 newch = channel_allocate(
2585 (x11_saved_proto == NULL) ?
2586 SSH_CHANNEL_OPEN : SSH_CHANNEL_X11_OPEN,
2588 channels[newch].remote_id = remote_channel;
2590 /* Send a confirmation to the remote host. */
2591 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2592 packet_put_int(remote_channel);
2593 packet_put_int(newch);
2598 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2600 deny_input_open(int type, int plen, void *ctxt)
2602 int rchan = packet_get_int();
2604 case SSH_SMSG_AGENT_OPEN:
2605 error("Warning: ssh server tried agent forwarding.");
2607 case SSH_SMSG_X11_OPEN:
2608 error("Warning: ssh server tried X11 forwarding.");
2611 error("deny_input_open: type %d plen %d", type, plen);
2614 error("Warning: this is probably a break in attempt by a malicious server.");
2615 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2616 packet_put_int(rchan);
2621 * Requests forwarding of X11 connections, generates fake authentication
2622 * data, and enables authentication spoofing.
2626 x11_request_forwarding_with_spoofing(int client_session_id,
2627 const char *proto, const char *data)
2629 u_int data_len = (u_int) strlen(data) / 2;
2630 u_int i, value, len;
2636 cp = getenv("DISPLAY");
2638 cp = strchr(cp, ':');
2640 cp = strchr(cp, '.');
2642 screen_number = atoi(cp + 1);
2646 /* Save protocol name. */
2647 x11_saved_proto = xstrdup(proto);
2650 * Extract real authentication data and generate fake data of the
2653 x11_saved_data = xmalloc(data_len);
2654 x11_fake_data = xmalloc(data_len);
2655 for (i = 0; i < data_len; i++) {
2656 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2657 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2659 rand = arc4random();
2660 x11_saved_data[i] = value;
2661 x11_fake_data[i] = rand & 0xff;
2664 x11_saved_data_len = data_len;
2665 x11_fake_data_len = data_len;
2667 /* Convert the fake data into hex. */
2668 len = 2 * data_len + 1;
2669 new_data = xmalloc(len);
2670 for (i = 0; i < data_len; i++)
2671 snprintf(new_data + 2 * i, len - 2 * i,
2672 "%02x", (u_char) x11_fake_data[i]);
2674 /* Send the request packet. */
2676 channel_request_start(client_session_id, "x11-req", 0);
2677 packet_put_char(0); /* XXX bool single connection */
2679 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2681 packet_put_cstring(proto);
2682 packet_put_cstring(new_data);
2683 packet_put_int(screen_number);
2685 packet_write_wait();
2689 /* Sends a message to the server to request authentication fd forwarding. */
2692 auth_request_forwarding()
2694 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2696 packet_write_wait();
2700 * Returns the name of the forwarded authentication socket. Returns NULL if
2701 * there is no forwarded authentication socket. The returned value points to
2706 auth_get_socket_name()
2708 return channel_forwarded_auth_socket_name;
2711 /* removes the agent forwarding socket */
2714 cleanup_socket(void)
2716 unlink(channel_forwarded_auth_socket_name);
2717 rmdir(channel_forwarded_auth_socket_dir);
2721 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2722 * This starts forwarding authentication requests.
2726 auth_input_request_forwarding(struct passwd * pw)
2729 struct sockaddr_un sunaddr;
2731 if (auth_get_socket_name() != NULL)
2732 fatal("Protocol error: authentication forwarding requested twice.");
2734 /* Temporarily drop privileged uid for mkdir/bind. */
2735 temporarily_use_uid(pw);
2737 /* Allocate a buffer for the socket name, and format the name. */
2738 channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
2739 channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
2740 strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
2742 /* Create private directory for socket */
2743 if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL) {
2744 packet_send_debug("Agent forwarding disabled: mkdtemp() failed: %.100s",
2747 xfree(channel_forwarded_auth_socket_name);
2748 xfree(channel_forwarded_auth_socket_dir);
2749 channel_forwarded_auth_socket_name = NULL;
2750 channel_forwarded_auth_socket_dir = NULL;
2753 snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
2754 channel_forwarded_auth_socket_dir, (int) getpid());
2756 if (atexit(cleanup_socket) < 0) {
2759 packet_disconnect("socket: %.100s", strerror(saved));
2761 /* Create the socket. */
2762 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2764 packet_disconnect("socket: %.100s", strerror(errno));
2766 /* Bind it to the name. */
2767 memset(&sunaddr, 0, sizeof(sunaddr));
2768 sunaddr.sun_family = AF_UNIX;
2769 strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
2770 sizeof(sunaddr.sun_path));
2772 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2773 packet_disconnect("bind: %.100s", strerror(errno));
2775 /* Restore the privileged uid. */
2778 /* Start listening on the socket. */
2779 if (listen(sock, 5) < 0)
2780 packet_disconnect("listen: %.100s", strerror(errno));
2782 /* Allocate a channel for the authentication agent socket. */
2783 newch = channel_new("auth socket",
2784 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2785 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2786 0, xstrdup("auth socket"), 1);
2788 strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
2789 sizeof(channels[newch].path));
2793 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2796 auth_input_open_request(int type, int plen, void *ctxt)
2798 int remch, sock, newch;
2801 packet_integrity_check(plen, 4, type);
2803 /* Read the remote channel number from the message. */
2804 remch = packet_get_int();
2807 * Get a connection to the local authentication agent (this may again
2810 sock = ssh_get_authentication_socket();
2813 * If we could not connect the agent, send an error message back to
2814 * the server. This should never happen unless the agent dies,
2815 * because authentication forwarding is only enabled if we have an
2819 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2820 packet_put_int(remch);
2824 debug("Forwarding authentication connection.");
2827 * Dummy host name. This will be freed when the channel is freed; it
2828 * will still be valid in the packet_put_string below since the
2829 * channel cannot yet be freed at that point.
2831 dummyname = xstrdup("authentication agent connection");
2833 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
2834 channels[newch].remote_id = remch;
2836 /* Send a confirmation to the remote host. */
2837 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2838 packet_put_int(remch);
2839 packet_put_int(newch);
2844 channel_start_open(int id)
2846 Channel *c = channel_lookup(id);
2848 log("channel_open: %d: bad id", id);
2851 debug("send channel open %d", id);
2852 packet_start(SSH2_MSG_CHANNEL_OPEN);
2853 packet_put_cstring(c->ctype);
2854 packet_put_int(c->self);
2855 packet_put_int(c->local_window);
2856 packet_put_int(c->local_maxpacket);
2859 channel_open(int id)
2862 channel_start_open(id);
2866 channel_request(int id, char *service, int wantconfirm)
2868 channel_request_start(id, service, wantconfirm);
2870 debug("channel request %d: %s", id, service) ;
2873 channel_request_start(int id, char *service, int wantconfirm)
2875 Channel *c = channel_lookup(id);
2877 log("channel_request: %d: bad id", id);
2880 packet_start(SSH2_MSG_CHANNEL_REQUEST);
2881 packet_put_int(c->remote_id);
2882 packet_put_cstring(service);
2883 packet_put_char(wantconfirm);
2886 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
2888 Channel *c = channel_lookup(id);
2890 log("channel_register_callback: %d: bad id", id);
2893 c->cb_event = mtype;
2898 channel_register_cleanup(int id, channel_callback_fn *fn)
2900 Channel *c = channel_lookup(id);
2902 log("channel_register_cleanup: %d: bad id", id);
2905 c->dettach_user = fn;
2908 channel_cancel_cleanup(int id)
2910 Channel *c = channel_lookup(id);
2912 log("channel_cancel_cleanup: %d: bad id", id);
2915 c->dettach_user = NULL;
2918 channel_register_filter(int id, channel_filter_fn *fn)
2920 Channel *c = channel_lookup(id);
2922 log("channel_register_filter: %d: bad id", id);
2925 c->input_filter = fn;
2929 channel_set_fds(int id, int rfd, int wfd, int efd,
2930 int extusage, int nonblock)
2932 Channel *c = channel_lookup(id);
2933 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
2934 fatal("channel_activate for non-larval channel %d.", id);
2935 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
2936 c->type = SSH_CHANNEL_OPEN;
2937 /* XXX window size? */
2938 c->local_window = c->local_window_max = c->local_maxpacket * 2;
2939 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2940 packet_put_int(c->remote_id);
2941 packet_put_int(c->local_window);