2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This file contains functions for generic socket connection forwarding.
6 * There is also code for initiating connection forwarding for X11 connections,
7 * arbitrary tcp/ip connections, and the authentication agent connection.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
15 * SSH2 support added by Markus Friedl.
16 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved.
17 * Copyright (c) 1999 Dug Song. All rights reserved.
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 RCSID("$OpenBSD: channels.c,v 1.139 2001/10/09 21:59:41 markus Exp $");
62 * Pointer to an array containing all allocated channels. The array is
63 * dynamically extended as needed.
65 static Channel **channels = NULL;
68 * Size of the channel array. All slots of the array must always be
69 * initialized (at least the type field); unused slots set to NULL
71 static int channels_alloc = 0;
74 * Maximum file descriptor value used in any of the channels. This is
75 * updated in channel_new.
77 static int channel_max_fd = 0;
80 /* -- tcp forwarding */
83 * Data structure for storing which hosts are permitted for forward requests.
84 * The local sides of any remote forwards are stored in this array to prevent
85 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
86 * network (which might be behind a firewall).
89 char *host_to_connect; /* Connect to 'host'. */
90 u_short port_to_connect; /* Connect to 'port'. */
91 u_short listen_port; /* Remote side should listen port number. */
94 /* List of all permitted host/port pairs to connect. */
95 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
97 /* Number of permitted host/port pairs in the array. */
98 static int num_permitted_opens = 0;
100 * If this is true, all opens are permitted. This is the case on the server
101 * on which we have to trust the client anyway, and the user could do
102 * anything after logging in anyway.
104 static int all_opens_permitted = 0;
107 /* -- X11 forwarding */
109 /* Maximum number of fake X11 displays to try. */
110 #define MAX_DISPLAYS 1000
112 /* Saved X11 authentication protocol name. */
113 static char *x11_saved_proto = NULL;
115 /* Saved X11 authentication data. This is the real data. */
116 static char *x11_saved_data = NULL;
117 static u_int x11_saved_data_len = 0;
120 * Fake X11 authentication data. This is what the server will be sending us;
121 * we should replace any occurrences of this by the real data.
123 static char *x11_fake_data = NULL;
124 static u_int x11_fake_data_len;
127 /* -- agent forwarding */
131 /* Name and directory of socket for authentication agent forwarding. */
132 static char *auth_sock_name = NULL;
133 static char *auth_sock_dir = NULL;
135 /* AF_UNSPEC or AF_INET or AF_INET6 */
136 static int IPv4or6 = AF_UNSPEC;
139 static void port_open_helper(Channel *c, char *rtype);
141 /* -- channel core */
144 channel_lookup(int id)
148 if (id < 0 || id > channels_alloc) {
149 log("channel_lookup: %d: bad id", id);
154 log("channel_lookup: %d: bad id: channel free", id);
161 * Register filedescriptors for a channel, used when allocating a channel or
162 * when the channel consumer/producer is ready, e.g. shell exec'd
166 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
167 int extusage, int nonblock)
169 /* Update the maximum file descriptor value. */
170 channel_max_fd = MAX(channel_max_fd, rfd);
171 channel_max_fd = MAX(channel_max_fd, wfd);
172 channel_max_fd = MAX(channel_max_fd, efd);
174 /* XXX set close-on-exec -markus */
178 c->sock = (rfd == wfd) ? rfd : -1;
180 c->extended_usage = extusage;
182 /* XXX ugly hack: nonblock is only set by the server */
183 if (nonblock && isatty(c->rfd)) {
184 debug("channel %d: rfd %d isatty", c->self, c->rfd);
186 if (!isatty(c->wfd)) {
187 error("channel %d: wfd %d is not a tty?",
194 /* enable nonblocking mode */
206 * Allocate a new channel object and set its type and socket. This will cause
207 * remote_name to be freed.
211 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
212 int window, int maxpack, int extusage, char *remote_name, int nonblock)
217 /* Do initial allocation if this is the first call. */
218 if (channels_alloc == 0) {
221 channels = xmalloc(channels_alloc * sizeof(Channel *));
222 for (i = 0; i < channels_alloc; i++)
224 fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
226 /* Try to find a free slot where to put the new channel. */
227 for (found = -1, i = 0; i < channels_alloc; i++)
228 if (channels[i] == NULL) {
229 /* Found a free slot. */
234 /* There are no free slots. Take last+1 slot and expand the array. */
235 found = channels_alloc;
236 channels_alloc += 10;
237 debug2("channel: expanding %d", channels_alloc);
238 channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
239 for (i = found; i < channels_alloc; i++)
242 /* Initialize and return new channel. */
243 c = channels[found] = xmalloc(sizeof(Channel));
244 memset(c, 0, sizeof(Channel));
245 buffer_init(&c->input);
246 buffer_init(&c->output);
247 buffer_init(&c->extended);
248 chan_init_iostates(c);
249 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
253 c->local_window = window;
254 c->local_window_max = window;
255 c->local_consumed = 0;
256 c->local_maxpacket = maxpack;
258 c->remote_name = remote_name;
259 c->remote_window = 0;
260 c->remote_maxpacket = 0;
265 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_close_fds: channel %d: 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_free: channel %d: %s, nchannels %d", c->self,
328 c->remote_name ? c->remote_name : "???", n);
330 s = channel_open_message();
331 debug3("channel_free: status: %s", s);
334 if (c->detach_user != NULL) {
335 debug("channel_free: channel %d: detaching channel user", c->self);
336 c->detach_user(c->self, NULL);
339 shutdown(c->sock, SHUT_RDWR);
340 channel_close_fds(c);
341 buffer_free(&c->input);
342 buffer_free(&c->output);
343 buffer_free(&c->extended);
344 if (c->remote_name) {
345 xfree(c->remote_name);
346 c->remote_name = NULL;
348 channels[c->self] = NULL;
353 channel_free_all(void)
357 for (i = 0; i < channels_alloc; i++)
358 if (channels[i] != NULL)
359 channel_free(channels[i]);
363 * Closes the sockets/fds of all channels. This is used to close extra file
364 * descriptors after a fork.
372 for (i = 0; i < channels_alloc; i++)
373 if (channels[i] != NULL)
374 channel_close_fds(channels[i]);
378 * Stop listening to channels.
382 channel_stop_listening(void)
387 for (i = 0; i < channels_alloc; i++) {
391 case SSH_CHANNEL_AUTH_SOCKET:
392 case SSH_CHANNEL_PORT_LISTENER:
393 case SSH_CHANNEL_RPORT_LISTENER:
394 case SSH_CHANNEL_X11_LISTENER:
395 channel_close_fd(&c->sock);
404 * Returns true if no channel has too much buffered data, and false if one or
405 * more channel is overfull.
409 channel_not_very_much_buffered_data()
414 for (i = 0; i < channels_alloc; i++) {
416 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
419 buffer_len(&c->input) > packet_get_maxsize()) {
420 debug("channel %d: big input buffer %d",
421 c->self, buffer_len(&c->input));
425 if (buffer_len(&c->output) > packet_get_maxsize()) {
426 debug("channel %d: big output buffer %d > %d",
427 c->self, buffer_len(&c->output),
428 packet_get_maxsize());
436 /* Returns true if any channel is still open. */
444 for (i = 0; i < channels_alloc; i++) {
449 case SSH_CHANNEL_X11_LISTENER:
450 case SSH_CHANNEL_PORT_LISTENER:
451 case SSH_CHANNEL_RPORT_LISTENER:
452 case SSH_CHANNEL_CLOSED:
453 case SSH_CHANNEL_AUTH_SOCKET:
454 case SSH_CHANNEL_DYNAMIC:
455 case SSH_CHANNEL_CONNECTING:
456 case SSH_CHANNEL_ZOMBIE:
458 case SSH_CHANNEL_LARVAL:
460 fatal("cannot happen: SSH_CHANNEL_LARVAL");
462 case SSH_CHANNEL_OPENING:
463 case SSH_CHANNEL_OPEN:
464 case SSH_CHANNEL_X11_OPEN:
466 case SSH_CHANNEL_INPUT_DRAINING:
467 case SSH_CHANNEL_OUTPUT_DRAINING:
469 fatal("cannot happen: OUT_DRAIN");
472 fatal("channel_still_open: bad channel type %d", c->type);
479 /* Returns the id of an open channel suitable for keepaliving */
487 for (i = 0; i < channels_alloc; i++) {
492 case SSH_CHANNEL_CLOSED:
493 case SSH_CHANNEL_DYNAMIC:
494 case SSH_CHANNEL_X11_LISTENER:
495 case SSH_CHANNEL_PORT_LISTENER:
496 case SSH_CHANNEL_RPORT_LISTENER:
497 case SSH_CHANNEL_OPENING:
498 case SSH_CHANNEL_CONNECTING:
499 case SSH_CHANNEL_ZOMBIE:
501 case SSH_CHANNEL_LARVAL:
502 case SSH_CHANNEL_AUTH_SOCKET:
503 case SSH_CHANNEL_OPEN:
504 case SSH_CHANNEL_X11_OPEN:
506 case SSH_CHANNEL_INPUT_DRAINING:
507 case SSH_CHANNEL_OUTPUT_DRAINING:
509 fatal("cannot happen: OUT_DRAIN");
512 fatal("channel_find_open: bad channel type %d", c->type);
521 * Returns a message describing the currently open forwarded connections,
522 * suitable for sending to the client. The message contains crlf pairs for
527 channel_open_message()
534 buffer_init(&buffer);
535 snprintf(buf, sizeof buf, "The following connections are open:\r\n");
536 buffer_append(&buffer, buf, strlen(buf));
537 for (i = 0; i < channels_alloc; i++) {
542 case SSH_CHANNEL_X11_LISTENER:
543 case SSH_CHANNEL_PORT_LISTENER:
544 case SSH_CHANNEL_RPORT_LISTENER:
545 case SSH_CHANNEL_CLOSED:
546 case SSH_CHANNEL_AUTH_SOCKET:
547 case SSH_CHANNEL_ZOMBIE:
549 case SSH_CHANNEL_LARVAL:
550 case SSH_CHANNEL_OPENING:
551 case SSH_CHANNEL_CONNECTING:
552 case SSH_CHANNEL_DYNAMIC:
553 case SSH_CHANNEL_OPEN:
554 case SSH_CHANNEL_X11_OPEN:
555 case SSH_CHANNEL_INPUT_DRAINING:
556 case SSH_CHANNEL_OUTPUT_DRAINING:
557 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
558 c->self, c->remote_name,
559 c->type, c->remote_id,
560 c->istate, buffer_len(&c->input),
561 c->ostate, buffer_len(&c->output),
563 buffer_append(&buffer, buf, strlen(buf));
566 fatal("channel_open_message: bad channel type %d", c->type);
570 buffer_append(&buffer, "\0", 1);
571 cp = xstrdup(buffer_ptr(&buffer));
572 buffer_free(&buffer);
577 channel_send_open(int id)
579 Channel *c = channel_lookup(id);
581 log("channel_send_open: %d: bad id", id);
584 debug("send channel open %d", id);
585 packet_start(SSH2_MSG_CHANNEL_OPEN);
586 packet_put_cstring(c->ctype);
587 packet_put_int(c->self);
588 packet_put_int(c->local_window);
589 packet_put_int(c->local_maxpacket);
594 channel_request(int id, char *service, int wantconfirm)
596 channel_request_start(id, service, wantconfirm);
598 debug("channel request %d: %s", id, service) ;
601 channel_request_start(int id, char *service, int wantconfirm)
603 Channel *c = channel_lookup(id);
605 log("channel_request: %d: bad id", id);
608 packet_start(SSH2_MSG_CHANNEL_REQUEST);
609 packet_put_int(c->remote_id);
610 packet_put_cstring(service);
611 packet_put_char(wantconfirm);
614 channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
616 Channel *c = channel_lookup(id);
618 log("channel_register_callback: %d: bad id", id);
626 channel_register_cleanup(int id, channel_callback_fn *fn)
628 Channel *c = channel_lookup(id);
630 log("channel_register_cleanup: %d: bad id", id);
636 channel_cancel_cleanup(int id)
638 Channel *c = channel_lookup(id);
640 log("channel_cancel_cleanup: %d: bad id", id);
643 c->detach_user = NULL;
646 channel_register_filter(int id, channel_filter_fn *fn)
648 Channel *c = channel_lookup(id);
650 log("channel_register_filter: %d: bad id", id);
653 c->input_filter = fn;
657 channel_set_fds(int id, int rfd, int wfd, int efd,
658 int extusage, int nonblock)
660 Channel *c = channel_lookup(id);
661 if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
662 fatal("channel_activate for non-larval channel %d.", id);
663 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
664 c->type = SSH_CHANNEL_OPEN;
665 /* XXX window size? */
666 c->local_window = c->local_window_max = c->local_maxpacket * 2;
667 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
668 packet_put_int(c->remote_id);
669 packet_put_int(c->local_window);
674 * 'channel_pre*' are called just before select() to add any bits relevant to
675 * channels in the select bitmasks.
678 * 'channel_post*': perform any appropriate operations for channels which
679 * have events pending.
681 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
682 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
683 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
686 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
688 FD_SET(c->sock, readset);
692 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
694 debug3("channel %d: waiting for connection", c->self);
695 FD_SET(c->sock, writeset);
699 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
701 if (buffer_len(&c->input) < packet_get_maxsize())
702 FD_SET(c->sock, readset);
703 if (buffer_len(&c->output) > 0)
704 FD_SET(c->sock, writeset);
708 channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
710 /* test whether sockets are 'alive' for read/write */
711 if (c->istate == CHAN_INPUT_OPEN)
712 if (buffer_len(&c->input) < packet_get_maxsize())
713 FD_SET(c->sock, readset);
714 if (c->ostate == CHAN_OUTPUT_OPEN ||
715 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
716 if (buffer_len(&c->output) > 0) {
717 FD_SET(c->sock, writeset);
718 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
725 channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
727 if (c->istate == CHAN_INPUT_OPEN &&
728 c->remote_window > 0 &&
729 buffer_len(&c->input) < c->remote_window)
730 FD_SET(c->rfd, readset);
731 if (c->ostate == CHAN_OUTPUT_OPEN ||
732 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
733 if (buffer_len(&c->output) > 0) {
734 FD_SET(c->wfd, writeset);
735 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
739 /** XXX check close conditions, too */
741 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
742 buffer_len(&c->extended) > 0)
743 FD_SET(c->efd, writeset);
744 else if (c->extended_usage == CHAN_EXTENDED_READ &&
745 buffer_len(&c->extended) < c->remote_window)
746 FD_SET(c->efd, readset);
751 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
753 if (buffer_len(&c->input) == 0) {
754 packet_start(SSH_MSG_CHANNEL_CLOSE);
755 packet_put_int(c->remote_id);
757 c->type = SSH_CHANNEL_CLOSED;
758 debug("channel %d: closing after input drain.", c->self);
763 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
765 if (buffer_len(&c->output) == 0)
768 FD_SET(c->sock, writeset);
772 * This is a special state for X11 authentication spoofing. An opened X11
773 * connection (when authentication spoofing is being done) remains in this
774 * state until the first packet has been completely read. The authentication
775 * data in that packet is then substituted by the real data if it matches the
776 * fake data, and the channel is put into normal mode.
777 * XXX All this happens at the client side.
778 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
781 x11_open_helper(Buffer *b)
784 u_int proto_len, data_len;
786 /* Check if the fixed size part of the packet is in buffer. */
787 if (buffer_len(b) < 12)
790 /* Parse the lengths of variable-length fields. */
791 ucp = (u_char *) buffer_ptr(b);
792 if (ucp[0] == 0x42) { /* Byte order MSB first. */
793 proto_len = 256 * ucp[6] + ucp[7];
794 data_len = 256 * ucp[8] + ucp[9];
795 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
796 proto_len = ucp[6] + 256 * ucp[7];
797 data_len = ucp[8] + 256 * ucp[9];
799 debug("Initial X11 packet contains bad byte order byte: 0x%x",
804 /* Check if the whole packet is in buffer. */
806 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
809 /* Check if authentication protocol matches. */
810 if (proto_len != strlen(x11_saved_proto) ||
811 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
812 debug("X11 connection uses different authentication protocol.");
815 /* Check if authentication data matches our fake data. */
816 if (data_len != x11_fake_data_len ||
817 memcmp(ucp + 12 + ((proto_len + 3) & ~3),
818 x11_fake_data, x11_fake_data_len) != 0) {
819 debug("X11 auth data does not match fake data.");
822 /* Check fake data length */
823 if (x11_fake_data_len != x11_saved_data_len) {
824 error("X11 fake_data_len %d != saved_data_len %d",
825 x11_fake_data_len, x11_saved_data_len);
829 * Received authentication protocol and data match
830 * our fake data. Substitute the fake data with real
833 memcpy(ucp + 12 + ((proto_len + 3) & ~3),
834 x11_saved_data, x11_saved_data_len);
839 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
841 int ret = x11_open_helper(&c->output);
843 /* Start normal processing for the channel. */
844 c->type = SSH_CHANNEL_OPEN;
845 channel_pre_open_13(c, readset, writeset);
846 } else if (ret == -1) {
848 * We have received an X11 connection that has bad
849 * authentication information.
851 log("X11 connection rejected because of wrong authentication.");
852 buffer_clear(&c->input);
853 buffer_clear(&c->output);
854 channel_close_fd(&c->sock);
856 c->type = SSH_CHANNEL_CLOSED;
857 packet_start(SSH_MSG_CHANNEL_CLOSE);
858 packet_put_int(c->remote_id);
864 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
866 int ret = x11_open_helper(&c->output);
868 /* c->force_drain = 1; */
871 c->type = SSH_CHANNEL_OPEN;
873 channel_pre_open_20(c, readset, writeset);
875 channel_pre_open_15(c, readset, writeset);
876 } else if (ret == -1) {
877 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
878 chan_read_failed(c); /** force close? */
879 chan_write_failed(c);
880 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
884 /* try to decode a socks4 header */
886 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
889 int len, have, i, found;
895 struct in_addr dest_addr;
898 debug2("channel %d: decode socks4", c->self);
900 have = buffer_len(&c->input);
901 len = sizeof(s4_req);
904 p = buffer_ptr(&c->input);
905 for (found = 0, i = len; i < have; i++) {
911 /* the peer is probably sending garbage */
912 debug("channel %d: decode socks4: too long",
919 buffer_get(&c->input, (char *)&s4_req.version, 1);
920 buffer_get(&c->input, (char *)&s4_req.command, 1);
921 buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
922 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
923 have = buffer_len(&c->input);
924 p = buffer_ptr(&c->input);
926 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
928 fatal("channel %d: decode socks4: len %d > have %d",
930 strlcpy(username, p, sizeof(username));
931 buffer_consume(&c->input, len);
932 buffer_consume(&c->input, 1); /* trailing '\0' */
934 host = inet_ntoa(s4_req.dest_addr);
935 strlcpy(c->path, host, sizeof(c->path));
936 c->host_port = ntohs(s4_req.dest_port);
938 debug("channel %d: dynamic request: socks4 host %s port %u command %u",
939 c->self, host, c->host_port, s4_req.command);
941 if (s4_req.command != 1) {
942 debug("channel %d: cannot handle: socks4 cn %d",
943 c->self, s4_req.command);
946 s4_rsp.version = 0; /* vn: 0 for reply */
947 s4_rsp.command = 90; /* cd: req granted */
948 s4_rsp.dest_port = 0; /* ignored */
949 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
950 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
954 /* dynamic port forwarding */
956 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
961 have = buffer_len(&c->input);
963 debug2("channel %d: pre_dynamic: have %d", c->self, have);
964 /* buffer_dump(&c->input); */
965 /* check if the fixed size part of the packet is in buffer. */
968 FD_SET(c->sock, readset);
971 /* try to guess the protocol */
972 p = buffer_ptr(&c->input);
975 ret = channel_decode_socks4(c, readset, writeset);
983 } else if (ret == 0) {
984 debug2("channel %d: pre_dynamic: need more", c->self);
986 FD_SET(c->sock, readset);
988 /* switch to the next state */
989 c->type = SSH_CHANNEL_OPENING;
990 port_open_helper(c, "direct-tcpip");
994 /* This is our fake X11 server socket. */
996 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
999 struct sockaddr addr;
1002 char buf[16384], *remote_ipaddr;
1005 if (FD_ISSET(c->sock, readset)) {
1006 debug("X11 connection requested.");
1007 addrlen = sizeof(addr);
1008 newsock = accept(c->sock, &addr, &addrlen);
1010 error("accept: %.100s", strerror(errno));
1013 remote_ipaddr = get_peer_ipaddr(newsock);
1014 remote_port = get_peer_port(newsock);
1015 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1016 remote_ipaddr, remote_port);
1018 nc = channel_new("accepted x11 socket",
1019 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1020 c->local_window_max, c->local_maxpacket,
1021 0, xstrdup(buf), 1);
1024 xfree(remote_ipaddr);
1028 packet_start(SSH2_MSG_CHANNEL_OPEN);
1029 packet_put_cstring("x11");
1030 packet_put_int(nc->self);
1031 packet_put_int(c->local_window_max);
1032 packet_put_int(c->local_maxpacket);
1033 /* originator ipaddr and port */
1034 packet_put_cstring(remote_ipaddr);
1035 if (datafellows & SSH_BUG_X11FWD) {
1036 debug("ssh2 x11 bug compat mode");
1038 packet_put_int(remote_port);
1042 packet_start(SSH_SMSG_X11_OPEN);
1043 packet_put_int(nc->self);
1044 if (packet_get_protocol_flags() &
1045 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1046 packet_put_cstring(buf);
1049 xfree(remote_ipaddr);
1054 port_open_helper(Channel *c, char *rtype)
1058 char *remote_ipaddr = get_peer_ipaddr(c->sock);
1059 u_short remote_port = get_peer_port(c->sock);
1061 direct = (strcmp(rtype, "direct-tcpip") == 0);
1063 snprintf(buf, sizeof buf,
1064 "%s: listening port %d for %.100s port %d, "
1065 "connect from %.200s port %d",
1066 rtype, c->listening_port, c->path, c->host_port,
1067 remote_ipaddr, remote_port);
1069 xfree(c->remote_name);
1070 c->remote_name = xstrdup(buf);
1073 packet_start(SSH2_MSG_CHANNEL_OPEN);
1074 packet_put_cstring(rtype);
1075 packet_put_int(c->self);
1076 packet_put_int(c->local_window_max);
1077 packet_put_int(c->local_maxpacket);
1079 /* target host, port */
1080 packet_put_cstring(c->path);
1081 packet_put_int(c->host_port);
1083 /* listen address, port */
1084 packet_put_cstring(c->path);
1085 packet_put_int(c->listening_port);
1087 /* originator host and port */
1088 packet_put_cstring(remote_ipaddr);
1089 packet_put_int(remote_port);
1092 packet_start(SSH_MSG_PORT_OPEN);
1093 packet_put_int(c->self);
1094 packet_put_cstring(c->path);
1095 packet_put_int(c->host_port);
1096 if (packet_get_protocol_flags() &
1097 SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1098 packet_put_cstring(c->remote_name);
1101 xfree(remote_ipaddr);
1105 * This socket is listening for connections to a forwarded TCP/IP port.
1108 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
1111 struct sockaddr addr;
1112 int newsock, nextstate;
1116 if (FD_ISSET(c->sock, readset)) {
1117 debug("Connection to port %d forwarding "
1118 "to %.100s port %d requested.",
1119 c->listening_port, c->path, c->host_port);
1121 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1122 nextstate = SSH_CHANNEL_OPENING;
1123 rtype = "forwarded-tcpip";
1125 if (c->host_port == 0) {
1126 nextstate = SSH_CHANNEL_DYNAMIC;
1127 rtype = "dynamic-tcpip";
1129 nextstate = SSH_CHANNEL_OPENING;
1130 rtype = "direct-tcpip";
1134 addrlen = sizeof(addr);
1135 newsock = accept(c->sock, &addr, &addrlen);
1137 error("accept: %.100s", strerror(errno));
1140 nc = channel_new(rtype,
1141 nextstate, newsock, newsock, -1,
1142 c->local_window_max, c->local_maxpacket,
1143 0, xstrdup(rtype), 1);
1145 error("channel_post_port_listener: no new channel:");
1149 nc->listening_port = c->listening_port;
1150 nc->host_port = c->host_port;
1151 strlcpy(nc->path, c->path, sizeof(nc->path));
1153 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1155 * do not call the channel_post handler until
1156 * this flag has been reset by a pre-handler.
1157 * otherwise the FD_ISSET calls might overflow
1161 port_open_helper(nc, rtype);
1167 * This is the authentication agent socket listening for connections from
1171 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
1176 struct sockaddr addr;
1179 if (FD_ISSET(c->sock, readset)) {
1180 addrlen = sizeof(addr);
1181 newsock = accept(c->sock, &addr, &addrlen);
1183 error("accept from auth socket: %.100s", strerror(errno));
1186 name = xstrdup("accepted auth socket");
1187 nc = channel_new("accepted auth socket",
1188 SSH_CHANNEL_OPENING, newsock, newsock, -1,
1189 c->local_window_max, c->local_maxpacket,
1192 error("channel_post_auth_listener: channel_new failed");
1197 packet_start(SSH2_MSG_CHANNEL_OPEN);
1198 packet_put_cstring("auth-agent@openssh.com");
1199 packet_put_int(nc->self);
1200 packet_put_int(c->local_window_max);
1201 packet_put_int(c->local_maxpacket);
1203 packet_start(SSH_SMSG_AGENT_OPEN);
1204 packet_put_int(nc->self);
1211 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
1214 socklen_t sz = sizeof(err);
1216 if (FD_ISSET(c->sock, writeset)) {
1217 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
1220 error("getsockopt SO_ERROR failed");
1223 debug("channel %d: connected", c->self);
1224 c->type = SSH_CHANNEL_OPEN;
1226 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1227 packet_put_int(c->remote_id);
1228 packet_put_int(c->self);
1229 packet_put_int(c->local_window);
1230 packet_put_int(c->local_maxpacket);
1232 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1233 packet_put_int(c->remote_id);
1234 packet_put_int(c->self);
1237 debug("channel %d: not connected: %s",
1238 c->self, strerror(err));
1240 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1241 packet_put_int(c->remote_id);
1242 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1243 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1244 packet_put_cstring(strerror(err));
1245 packet_put_cstring("");
1248 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1249 packet_put_int(c->remote_id);
1258 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
1264 FD_ISSET(c->rfd, readset)) {
1265 len = read(c->rfd, buf, sizeof(buf));
1266 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1269 debug("channel %d: read<=0 rfd %d len %d",
1270 c->self, c->rfd, len);
1271 if (c->type != SSH_CHANNEL_OPEN) {
1272 debug("channel %d: not open", c->self);
1275 } else if (compat13) {
1276 buffer_consume(&c->output, buffer_len(&c->output));
1277 c->type = SSH_CHANNEL_INPUT_DRAINING;
1278 debug("channel %d: input draining.", c->self);
1280 chan_read_failed(c);
1284 if(c->input_filter != NULL) {
1285 if (c->input_filter(c, buf, len) == -1) {
1286 debug("channel %d: filter stops", c->self);
1287 chan_read_failed(c);
1290 buffer_append(&c->input, buf, len);
1296 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
1303 /* Send buffered output data to the socket. */
1305 FD_ISSET(c->wfd, writeset) &&
1306 buffer_len(&c->output) > 0) {
1307 data = buffer_ptr(&c->output);
1308 dlen = buffer_len(&c->output);
1309 len = write(c->wfd, data, dlen);
1310 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1313 if (c->type != SSH_CHANNEL_OPEN) {
1314 debug("channel %d: not open", c->self);
1317 } else if (compat13) {
1318 buffer_consume(&c->output, buffer_len(&c->output));
1319 debug("channel %d: input draining.", c->self);
1320 c->type = SSH_CHANNEL_INPUT_DRAINING;
1322 chan_write_failed(c);
1326 if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
1327 if (tcgetattr(c->wfd, &tio) == 0 &&
1328 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1330 * Simulate echo to reduce the impact of
1331 * traffic analysis. We need to match the
1332 * size of a SSH2_MSG_CHANNEL_DATA message
1333 * (4 byte channel id + data)
1335 packet_send_ignore(4 + len);
1339 buffer_consume(&c->output, len);
1340 if (compat20 && len > 0) {
1341 c->local_consumed += len;
1347 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
1352 /** XXX handle drain efd, too */
1354 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1355 FD_ISSET(c->efd, writeset) &&
1356 buffer_len(&c->extended) > 0) {
1357 len = write(c->efd, buffer_ptr(&c->extended),
1358 buffer_len(&c->extended));
1359 debug2("channel %d: written %d to efd %d",
1360 c->self, len, c->efd);
1361 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1364 debug2("channel %d: closing write-efd %d",
1366 channel_close_fd(&c->efd);
1368 buffer_consume(&c->extended, len);
1369 c->local_consumed += len;
1371 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1372 FD_ISSET(c->efd, readset)) {
1373 len = read(c->efd, buf, sizeof(buf));
1374 debug2("channel %d: read %d from efd %d",
1375 c->self, len, c->efd);
1376 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1379 debug2("channel %d: closing read-efd %d",
1381 channel_close_fd(&c->efd);
1383 buffer_append(&c->extended, buf, len);
1390 channel_check_window(Channel *c)
1392 if (c->type == SSH_CHANNEL_OPEN &&
1393 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1394 c->local_window < c->local_window_max/2 &&
1395 c->local_consumed > 0) {
1396 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1397 packet_put_int(c->remote_id);
1398 packet_put_int(c->local_consumed);
1400 debug2("channel %d: window %d sent adjust %d",
1401 c->self, c->local_window,
1403 c->local_window += c->local_consumed;
1404 c->local_consumed = 0;
1410 channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset)
1414 channel_handle_rfd(c, readset, writeset);
1415 channel_handle_wfd(c, readset, writeset);
1419 channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset)
1423 channel_handle_rfd(c, readset, writeset);
1424 channel_handle_wfd(c, readset, writeset);
1425 channel_handle_efd(c, readset, writeset);
1427 channel_check_window(c);
1431 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
1434 /* Send buffered output data to the socket. */
1435 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1436 len = write(c->sock, buffer_ptr(&c->output),
1437 buffer_len(&c->output));
1439 buffer_consume(&c->output, buffer_len(&c->output));
1441 buffer_consume(&c->output, len);
1446 channel_handler_init_20(void)
1448 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20;
1449 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1450 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1451 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
1452 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1453 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1454 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1455 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1457 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2;
1458 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1459 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
1460 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1461 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1462 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1463 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2;
1467 channel_handler_init_13(void)
1469 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
1470 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
1471 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1472 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1473 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1474 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
1475 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
1476 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1477 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1479 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1480 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1481 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1482 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1483 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
1484 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1485 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1489 channel_handler_init_15(void)
1491 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15;
1492 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
1493 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
1494 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
1495 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
1496 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
1497 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
1499 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
1500 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
1501 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
1502 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1;
1503 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
1504 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1;
1508 channel_handler_init(void)
1511 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1512 channel_pre[i] = NULL;
1513 channel_post[i] = NULL;
1516 channel_handler_init_20();
1518 channel_handler_init_13();
1520 channel_handler_init_15();
1524 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
1526 static int did_init = 0;
1531 channel_handler_init();
1534 for (i = 0; i < channels_alloc; i++) {
1538 if (ftab[c->type] != NULL)
1539 (*ftab[c->type])(c, readset, writeset);
1540 if (chan_is_dead(c)) {
1542 * we have to remove the fd's from the select mask
1543 * before the channels are free'd and the fd's are
1547 FD_CLR(c->wfd, writeset);
1549 FD_CLR(c->rfd, readset);
1551 if (c->extended_usage == CHAN_EXTENDED_READ)
1552 FD_CLR(c->efd, readset);
1553 if (c->extended_usage == CHAN_EXTENDED_WRITE)
1554 FD_CLR(c->efd, writeset);
1562 * Allocate/update select bitmasks and add any bits relevant to channels in
1566 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1567 int *nallocp, int rekeying)
1572 n = MAX(*maxfdp, channel_max_fd);
1574 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
1575 /* perhaps check sz < nalloc/2 and shrink? */
1576 if (*readsetp == NULL || sz > *nallocp) {
1577 *readsetp = xrealloc(*readsetp, sz);
1578 *writesetp = xrealloc(*writesetp, sz);
1582 memset(*readsetp, 0, sz);
1583 memset(*writesetp, 0, sz);
1586 channel_handler(channel_pre, *readsetp, *writesetp);
1590 * After select, perform any appropriate operations for channels which have
1594 channel_after_select(fd_set * readset, fd_set * writeset)
1596 channel_handler(channel_post, readset, writeset);
1600 /* If there is data to send to the connection, enqueue some of it now. */
1603 channel_output_poll()
1608 for (i = 0; i < channels_alloc; i++) {
1614 * We are only interested in channels that can have buffered
1618 if (c->type != SSH_CHANNEL_OPEN &&
1619 c->type != SSH_CHANNEL_INPUT_DRAINING)
1622 if (c->type != SSH_CHANNEL_OPEN)
1626 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
1627 /* XXX is this true? */
1628 debug2("channel %d: no data after CLOSE", c->self);
1632 /* Get the amount of buffered data for this channel. */
1633 if ((c->istate == CHAN_INPUT_OPEN ||
1634 c->istate == CHAN_INPUT_WAIT_DRAIN) &&
1635 (len = buffer_len(&c->input)) > 0) {
1637 * Send some data for the other side over the secure
1641 if (len > c->remote_window)
1642 len = c->remote_window;
1643 if (len > c->remote_maxpacket)
1644 len = c->remote_maxpacket;
1646 if (packet_is_interactive()) {
1650 /* Keep the packets at reasonable size. */
1651 if (len > packet_get_maxsize()/2)
1652 len = packet_get_maxsize()/2;
1656 packet_start(compat20 ?
1657 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
1658 packet_put_int(c->remote_id);
1659 packet_put_string(buffer_ptr(&c->input), len);
1661 buffer_consume(&c->input, len);
1662 c->remote_window -= len;
1664 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1666 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
1668 * input-buffer is empty and read-socket shutdown:
1669 * tell peer, that we will not send more data: send IEOF
1673 /* Send extended data, i.e. stderr */
1675 c->remote_window > 0 &&
1676 (len = buffer_len(&c->extended)) > 0 &&
1677 c->extended_usage == CHAN_EXTENDED_READ) {
1678 debug2("channel %d: rwin %d elen %d euse %d",
1679 c->self, c->remote_window, buffer_len(&c->extended),
1681 if (len > c->remote_window)
1682 len = c->remote_window;
1683 if (len > c->remote_maxpacket)
1684 len = c->remote_maxpacket;
1685 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
1686 packet_put_int(c->remote_id);
1687 packet_put_int(SSH2_EXTENDED_DATA_STDERR);
1688 packet_put_string(buffer_ptr(&c->extended), len);
1690 buffer_consume(&c->extended, len);
1691 c->remote_window -= len;
1692 debug2("channel %d: sent ext data %d", c->self, len);
1698 /* -- protocol input */
1701 channel_input_data(int type, int plen, void *ctxt)
1708 /* Get the channel number and verify it. */
1709 id = packet_get_int();
1710 c = channel_lookup(id);
1712 packet_disconnect("Received data for nonexistent channel %d.", id);
1714 /* Ignore any data for non-open channels (might happen on close) */
1715 if (c->type != SSH_CHANNEL_OPEN &&
1716 c->type != SSH_CHANNEL_X11_OPEN)
1719 /* same for protocol 1.5 if output end is no longer open */
1720 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
1724 data = packet_get_string(&data_len);
1728 if (data_len > c->local_maxpacket) {
1729 log("channel %d: rcvd big packet %d, maxpack %d",
1730 c->self, data_len, c->local_maxpacket);
1732 if (data_len > c->local_window) {
1733 log("channel %d: rcvd too much data %d, win %d",
1734 c->self, data_len, c->local_window);
1738 c->local_window -= data_len;
1740 packet_integrity_check(plen, 4 + 4 + data_len, type);
1742 buffer_append(&c->output, data, data_len);
1747 channel_input_extended_data(int type, int plen, void *ctxt)
1755 /* Get the channel number and verify it. */
1756 id = packet_get_int();
1757 c = channel_lookup(id);
1760 packet_disconnect("Received extended_data for bad channel %d.", id);
1761 if (c->type != SSH_CHANNEL_OPEN) {
1762 log("channel %d: ext data for non open", id);
1765 tcode = packet_get_int();
1767 c->extended_usage != CHAN_EXTENDED_WRITE ||
1768 tcode != SSH2_EXTENDED_DATA_STDERR) {
1769 log("channel %d: bad ext data", c->self);
1772 data = packet_get_string(&data_len);
1774 if (data_len > c->local_window) {
1775 log("channel %d: rcvd too much extended_data %d, win %d",
1776 c->self, data_len, c->local_window);
1780 debug2("channel %d: rcvd ext data %d", c->self, data_len);
1781 c->local_window -= data_len;
1782 buffer_append(&c->extended, data, data_len);
1787 channel_input_ieof(int type, int plen, void *ctxt)
1792 packet_integrity_check(plen, 4, type);
1794 id = packet_get_int();
1795 c = channel_lookup(id);
1797 packet_disconnect("Received ieof for nonexistent channel %d.", id);
1800 /* XXX force input close */
1801 if (c->force_drain) {
1802 debug("channel %d: FORCE input drain", c->self);
1803 c->istate = CHAN_INPUT_WAIT_DRAIN;
1809 channel_input_close(int type, int plen, void *ctxt)
1814 packet_integrity_check(plen, 4, type);
1816 id = packet_get_int();
1817 c = channel_lookup(id);
1819 packet_disconnect("Received close for nonexistent channel %d.", id);
1822 * Send a confirmation that we have closed the channel and no more
1823 * data is coming for it.
1825 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
1826 packet_put_int(c->remote_id);
1830 * If the channel is in closed state, we have sent a close request,
1831 * and the other side will eventually respond with a confirmation.
1832 * Thus, we cannot free the channel here, because then there would be
1833 * no-one to receive the confirmation. The channel gets freed when
1834 * the confirmation arrives.
1836 if (c->type != SSH_CHANNEL_CLOSED) {
1838 * Not a closed channel - mark it as draining, which will
1839 * cause it to be freed later.
1841 buffer_consume(&c->input, buffer_len(&c->input));
1842 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
1846 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
1848 channel_input_oclose(int type, int plen, void *ctxt)
1850 int id = packet_get_int();
1851 Channel *c = channel_lookup(id);
1852 packet_integrity_check(plen, 4, type);
1854 packet_disconnect("Received oclose for nonexistent channel %d.", id);
1855 chan_rcvd_oclose(c);
1859 channel_input_close_confirmation(int type, int plen, void *ctxt)
1861 int id = packet_get_int();
1862 Channel *c = channel_lookup(id);
1866 packet_disconnect("Received close confirmation for "
1867 "out-of-range channel %d.", id);
1868 if (c->type != SSH_CHANNEL_CLOSED)
1869 packet_disconnect("Received close confirmation for "
1870 "non-closed channel %d (type %d).", id, c->type);
1875 channel_input_open_confirmation(int type, int plen, void *ctxt)
1881 packet_integrity_check(plen, 4 + 4, type);
1883 id = packet_get_int();
1884 c = channel_lookup(id);
1886 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1887 packet_disconnect("Received open confirmation for "
1888 "non-opening channel %d.", id);
1889 remote_id = packet_get_int();
1890 /* Record the remote channel number and mark that the channel is now open. */
1891 c->remote_id = remote_id;
1892 c->type = SSH_CHANNEL_OPEN;
1895 c->remote_window = packet_get_int();
1896 c->remote_maxpacket = packet_get_int();
1898 if (c->cb_fn != NULL && c->cb_event == type) {
1899 debug2("callback start");
1900 c->cb_fn(c->self, c->cb_arg);
1901 debug2("callback done");
1903 debug("channel %d: open confirm rwindow %d rmax %d", c->self,
1904 c->remote_window, c->remote_maxpacket);
1909 reason2txt(int reason)
1912 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
1913 return "administratively prohibited";
1914 case SSH2_OPEN_CONNECT_FAILED:
1915 return "connect failed";
1916 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
1917 return "unknown channel type";
1918 case SSH2_OPEN_RESOURCE_SHORTAGE:
1919 return "resource shortage";
1921 return "unknown reason";
1925 channel_input_open_failure(int type, int plen, void *ctxt)
1928 char *msg = NULL, *lang = NULL;
1932 packet_integrity_check(plen, 4, type);
1934 id = packet_get_int();
1935 c = channel_lookup(id);
1937 if (c==NULL || c->type != SSH_CHANNEL_OPENING)
1938 packet_disconnect("Received open failure for "
1939 "non-opening channel %d.", id);
1941 reason = packet_get_int();
1942 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1943 msg = packet_get_string(NULL);
1944 lang = packet_get_string(NULL);
1947 log("channel %d: open failed: %s%s%s", id,
1948 reason2txt(reason), msg ? ": ": "", msg ? msg : "");
1954 /* Free the channel. This will also close the socket. */
1959 channel_input_channel_request(int type, int plen, void *ctxt)
1964 id = packet_get_int();
1965 c = channel_lookup(id);
1968 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL))
1969 packet_disconnect("Received request for "
1970 "non-open channel %d.", id);
1971 if (c->cb_fn != NULL && c->cb_event == type) {
1972 debug2("callback start");
1973 c->cb_fn(c->self, c->cb_arg);
1974 debug2("callback done");
1976 char *service = packet_get_string(NULL);
1977 debug("channel %d: rcvd request for %s", c->self, service);
1978 debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event);
1984 channel_input_window_adjust(int type, int plen, void *ctxt)
1992 /* Get the channel number and verify it. */
1993 id = packet_get_int();
1994 c = channel_lookup(id);
1996 if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
1997 log("Received window adjust for "
1998 "non-open channel %d.", id);
2001 adjust = packet_get_int();
2003 debug2("channel %d: rcvd adjust %d", id, adjust);
2004 c->remote_window += adjust;
2008 channel_input_port_open(int type, int plen, void *ctxt)
2012 char *host, *originator_string;
2013 int remote_id, sock = -1;
2015 remote_id = packet_get_int();
2016 host = packet_get_string(NULL);
2017 host_port = packet_get_int();
2019 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2020 originator_string = packet_get_string(NULL);
2022 originator_string = xstrdup("unknown (remote did not supply name)");
2025 sock = channel_connect_to(host, host_port);
2027 c = channel_new("connected socket",
2028 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
2029 originator_string, 1);
2031 error("channel_input_port_open: channel_new failed");
2034 c->remote_id = remote_id;
2038 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2039 packet_put_int(remote_id);
2046 /* -- tcp forwarding */
2049 channel_set_af(int af)
2055 * Initiate forwarding of connections to local port "port" through the secure
2056 * channel to host:port from remote side.
2059 channel_request_local_forwarding(u_short listen_port, const char *host_to_connect,
2060 u_short port_to_connect, int gateway_ports)
2062 return channel_request_forwarding(
2064 host_to_connect, port_to_connect,
2065 gateway_ports, /*remote_fwd*/ 0);
2069 * If 'remote_fwd' is true we have a '-R style' listener for protocol 2
2070 * (SSH_CHANNEL_RPORT_LISTENER).
2073 channel_request_forwarding(
2074 const char *listen_address, u_short listen_port,
2075 const char *host_to_connect, u_short port_to_connect,
2076 int gateway_ports, int remote_fwd)
2079 int success, sock, on = 1, type;
2080 struct addrinfo hints, *ai, *aitop;
2081 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2083 struct linger linger;
2088 host = listen_address;
2089 type = SSH_CHANNEL_RPORT_LISTENER;
2091 host = host_to_connect;
2092 type = SSH_CHANNEL_PORT_LISTENER;
2095 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
2096 error("Forward host name too long.");
2100 /* XXX listen_address is currently ignored */
2102 * getaddrinfo returns a loopback address if the hostname is
2103 * set to NULL and hints.ai_flags is not AI_PASSIVE
2105 memset(&hints, 0, sizeof(hints));
2106 hints.ai_family = IPv4or6;
2107 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
2108 hints.ai_socktype = SOCK_STREAM;
2109 snprintf(strport, sizeof strport, "%d", listen_port);
2110 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
2111 packet_disconnect("getaddrinfo: fatal error");
2113 for (ai = aitop; ai; ai = ai->ai_next) {
2114 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2116 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2117 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2118 error("channel_request_forwarding: getnameinfo failed");
2121 /* Create a port to listen for the host. */
2122 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2124 /* this is no error since kernel may not support ipv6 */
2125 verbose("socket: %.100s", strerror(errno));
2129 * Set socket options. We would like the socket to disappear
2130 * as soon as it has been closed for whatever reason.
2132 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
2134 linger.l_linger = 5;
2135 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
2136 debug("Local forwarding listening on %s port %s.", ntop, strport);
2138 /* Bind the socket to the address. */
2139 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2140 /* address can be in use ipv6 address is already bound */
2142 error("bind: %.100s", strerror(errno));
2144 verbose("bind: %.100s", strerror(errno));
2149 /* Start listening for connections on the socket. */
2150 if (listen(sock, 5) < 0) {
2151 error("listen: %.100s", strerror(errno));
2155 /* Allocate a channel number for the socket. */
2156 c = channel_new("port listener", type, sock, sock, -1,
2157 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2158 0, xstrdup("port listener"), 1);
2160 error("channel_request_forwarding: channel_new failed");
2164 strlcpy(c->path, host, sizeof(c->path));
2165 c->host_port = port_to_connect;
2166 c->listening_port = listen_port;
2170 error("channel_request_forwarding: cannot listen to port: %d",
2172 freeaddrinfo(aitop);
2177 * Initiate forwarding of connections to port "port" on remote host through
2178 * the secure channel to host:port from local side.
2182 channel_request_remote_forwarding(u_short listen_port,
2183 const char *host_to_connect, u_short port_to_connect)
2185 int payload_len, type, success = 0;
2187 /* Record locally that connection to this host/port is permitted. */
2188 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2189 fatal("channel_request_remote_forwarding: too many forwards");
2191 /* Send the forward request to the remote side. */
2193 const char *address_to_bind = "0.0.0.0";
2194 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2195 packet_put_cstring("tcpip-forward");
2196 packet_put_char(0); /* boolean: want reply */
2197 packet_put_cstring(address_to_bind);
2198 packet_put_int(listen_port);
2200 packet_write_wait();
2201 /* Assume that server accepts the request */
2204 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2205 packet_put_int(listen_port);
2206 packet_put_cstring(host_to_connect);
2207 packet_put_int(port_to_connect);
2209 packet_write_wait();
2211 /* Wait for response from the remote side. */
2212 type = packet_read(&payload_len);
2214 case SSH_SMSG_SUCCESS:
2217 case SSH_SMSG_FAILURE:
2218 log("Warning: Server denied remote port forwarding.");
2221 /* Unknown packet */
2222 packet_disconnect("Protocol error for port forward request:"
2223 "received packet type %d.", type);
2227 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2228 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2229 permitted_opens[num_permitted_opens].listen_port = listen_port;
2230 num_permitted_opens++;
2235 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
2236 * listening for the port, and sends back a success reply (or disconnect
2237 * message if there was an error). This never returns if there was an error.
2241 channel_input_port_forward_request(int is_root, int gateway_ports)
2243 u_short port, host_port;
2246 /* Get arguments from the packet. */
2247 port = packet_get_int();
2248 hostname = packet_get_string(NULL);
2249 host_port = packet_get_int();
2253 * Check that an unprivileged user is not trying to forward a
2256 if (port < IPPORT_RESERVED && !is_root)
2257 packet_disconnect("Requested forwarding of port %d but user is not root.",
2260 /* Initiate forwarding */
2261 channel_request_local_forwarding(port, hostname, host_port, gateway_ports);
2263 /* Free the argument string. */
2268 * Permits opening to any host/port if permitted_opens[] is empty. This is
2269 * usually called by the server, because the user could connect to any port
2270 * anyway, and the server has no way to know but to trust the client anyway.
2273 channel_permit_all_opens()
2275 if (num_permitted_opens == 0)
2276 all_opens_permitted = 1;
2280 channel_add_permitted_opens(char *host, int port)
2282 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2283 fatal("channel_request_remote_forwarding: too many forwards");
2284 debug("allow port forwarding to host %s port %d", host, port);
2286 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2287 permitted_opens[num_permitted_opens].port_to_connect = port;
2288 num_permitted_opens++;
2290 all_opens_permitted = 0;
2294 channel_clear_permitted_opens(void)
2298 for (i = 0; i < num_permitted_opens; i++)
2299 xfree(permitted_opens[i].host_to_connect);
2300 num_permitted_opens = 0;
2305 /* return socket to remote host, port */
2307 connect_to(const char *host, u_short port)
2309 struct addrinfo hints, *ai, *aitop;
2310 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2314 memset(&hints, 0, sizeof(hints));
2315 hints.ai_family = IPv4or6;
2316 hints.ai_socktype = SOCK_STREAM;
2317 snprintf(strport, sizeof strport, "%d", port);
2318 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
2319 error("connect_to %.100s: unknown host (%s)", host,
2320 gai_strerror(gaierr));
2323 for (ai = aitop; ai; ai = ai->ai_next) {
2324 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2326 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2327 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2328 error("connect_to: getnameinfo failed");
2331 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2333 error("socket: %.100s", strerror(errno));
2336 if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
2337 fatal("connect_to: F_SETFL: %s", strerror(errno));
2338 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
2339 errno != EINPROGRESS) {
2340 error("connect_to %.100s port %s: %.100s", ntop, strport,
2343 continue; /* fail -- try next */
2345 break; /* success */
2348 freeaddrinfo(aitop);
2350 error("connect_to %.100s port %d: failed.", host, port);
2358 channel_connect_by_listen_address(u_short listen_port)
2362 for (i = 0; i < num_permitted_opens; i++)
2363 if (permitted_opens[i].listen_port == listen_port)
2365 permitted_opens[i].host_to_connect,
2366 permitted_opens[i].port_to_connect);
2367 error("WARNING: Server requests forwarding for unknown listen_port %d",
2372 /* Check if connecting to that port is permitted and connect. */
2374 channel_connect_to(const char *host, u_short port)
2378 permit = all_opens_permitted;
2380 for (i = 0; i < num_permitted_opens; i++)
2381 if (permitted_opens[i].port_to_connect == port &&
2382 strcmp(permitted_opens[i].host_to_connect, host) == 0)
2387 log("Received request to connect to host %.100s port %d, "
2388 "but the request was denied.", host, port);
2391 return connect_to(host, port);
2394 /* -- X11 forwarding */
2397 * Creates an internet domain socket for listening for X11 connections.
2398 * Returns a suitable value for the DISPLAY variable, or NULL if an error
2402 x11_create_display_inet(int screen_number, int x11_display_offset)
2404 int display_number, sock;
2406 struct addrinfo hints, *ai, *aitop;
2407 char strport[NI_MAXSERV];
2408 int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
2410 char hostname[MAXHOSTNAMELEN];
2412 for (display_number = x11_display_offset;
2413 display_number < MAX_DISPLAYS;
2415 port = 6000 + display_number;
2416 memset(&hints, 0, sizeof(hints));
2417 hints.ai_family = IPv4or6;
2418 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */
2419 hints.ai_socktype = SOCK_STREAM;
2420 snprintf(strport, sizeof strport, "%d", port);
2421 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
2422 error("getaddrinfo: %.100s", gai_strerror(gaierr));
2425 for (ai = aitop; ai; ai = ai->ai_next) {
2426 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
2428 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2430 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
2431 error("socket: %.100s", strerror(errno));
2434 debug("x11_create_display_inet: Socket family %d not supported",
2439 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2440 debug("bind port %d: %.100s", port, strerror(errno));
2441 shutdown(sock, SHUT_RDWR);
2447 for (n = 0; n < num_socks; n++) {
2448 shutdown(socks[n], SHUT_RDWR);
2454 socks[num_socks++] = sock;
2455 #ifndef DONT_TRY_OTHER_AF
2456 if (num_socks == NUM_SOCKS)
2462 freeaddrinfo(aitop);
2466 if (display_number >= MAX_DISPLAYS) {
2467 error("Failed to allocate internet-domain X11 display socket.");
2470 /* Start listening for connections on the socket. */
2471 for (n = 0; n < num_socks; n++) {
2473 if (listen(sock, 5) < 0) {
2474 error("listen: %.100s", strerror(errno));
2475 shutdown(sock, SHUT_RDWR);
2481 /* Set up a suitable value for the DISPLAY variable. */
2482 if (gethostname(hostname, sizeof(hostname)) < 0)
2483 fatal("gethostname: %.100s", strerror(errno));
2485 #ifdef IPADDR_IN_DISPLAY
2487 * HPUX detects the local hostname in the DISPLAY variable and tries
2488 * to set up a shared memory connection to the server, which it
2489 * incorrectly supposes to be local.
2491 * The workaround - as used in later $$H and other programs - is
2492 * is to set display to the host's IP address.
2496 struct in_addr my_addr;
2498 he = gethostbyname(hostname);
2500 error("[X11-broken-fwd-hostname-workaround] Could not get "
2501 "IP address for hostname %s.", hostname);
2503 packet_send_debug("[X11-broken-fwd-hostname-workaround]"
2504 "Could not get IP address for hostname %s.", hostname);
2506 shutdown(sock, SHUT_RDWR);
2512 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2514 /* Set DISPLAY to <ip address>:screen.display */
2515 snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr),
2516 display_number, screen_number);
2518 #else /* IPADDR_IN_DISPLAY */
2519 /* Just set DISPLAY to hostname:screen.display */
2520 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
2521 display_number, screen_number);
2522 #endif /* IPADDR_IN_DISPLAY */
2524 /* Allocate a channel for each socket. */
2525 for (n = 0; n < num_socks; n++) {
2527 (void) channel_new("x11 listener",
2528 SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
2529 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2530 0, xstrdup("X11 inet listener"), 1);
2533 /* Return a suitable value for the DISPLAY environment variable. */
2534 return xstrdup(display);
2538 #define X_UNIX_PATH "/tmp/.X11-unix/X"
2542 connect_local_xsocket(u_int dnr)
2544 static const char *const x_sockets[] = {
2546 "/var/X/.X11-unix/X" "%u",
2547 "/usr/spool/sockets/X11/" "%u",
2551 struct sockaddr_un addr;
2552 const char *const * path;
2554 for (path = x_sockets; *path; ++path) {
2555 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2557 error("socket: %.100s", strerror(errno));
2558 memset(&addr, 0, sizeof(addr));
2559 addr.sun_family = AF_UNIX;
2560 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr);
2561 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
2565 error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
2570 x11_connect_display(void)
2572 int display_number, sock = 0;
2573 const char *display;
2574 char buf[1024], *cp;
2575 struct addrinfo hints, *ai, *aitop;
2576 char strport[NI_MAXSERV];
2579 /* Try to open a socket for the local X server. */
2580 display = getenv("DISPLAY");
2582 error("DISPLAY not set.");
2586 * Now we decode the value of the DISPLAY variable and make a
2587 * connection to the real X server.
2591 * Check if it is a unix domain socket. Unix domain displays are in
2592 * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
2594 if (strncmp(display, "unix:", 5) == 0 ||
2595 display[0] == ':') {
2596 /* Connect to the unix domain socket. */
2597 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
2598 error("Could not parse display number from DISPLAY: %.100s",
2602 /* Create a socket. */
2603 sock = connect_local_xsocket(display_number);
2607 /* OK, we now have a connection to the display. */
2611 * Connect to an inet socket. The DISPLAY value is supposedly
2612 * hostname:d[.s], where hostname may also be numeric IP address.
2614 strncpy(buf, display, sizeof(buf));
2615 buf[sizeof(buf) - 1] = 0;
2616 cp = strchr(buf, ':');
2618 error("Could not find ':' in DISPLAY: %.100s", display);
2622 /* buf now contains the host name. But first we parse the display number. */
2623 if (sscanf(cp + 1, "%d", &display_number) != 1) {
2624 error("Could not parse display number from DISPLAY: %.100s",
2629 /* Look up the host address */
2630 memset(&hints, 0, sizeof(hints));
2631 hints.ai_family = IPv4or6;
2632 hints.ai_socktype = SOCK_STREAM;
2633 snprintf(strport, sizeof strport, "%d", 6000 + display_number);
2634 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
2635 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
2638 for (ai = aitop; ai; ai = ai->ai_next) {
2639 /* Create a socket. */
2640 sock = socket(ai->ai_family, SOCK_STREAM, 0);
2642 debug("socket: %.100s", strerror(errno));
2645 /* Connect it to the display. */
2646 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2647 debug("connect %.100s port %d: %.100s", buf,
2648 6000 + display_number, strerror(errno));
2655 freeaddrinfo(aitop);
2657 error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
2665 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
2666 * the remote channel number. We should do whatever we want, and respond
2667 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
2671 x11_input_open(int type, int plen, void *ctxt)
2674 int remote_id, sock = 0;
2677 debug("Received X11 open request.");
2679 remote_id = packet_get_int();
2681 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2682 remote_host = packet_get_string(NULL);
2684 remote_host = xstrdup("unknown (remote did not supply name)");
2688 /* Obtain a connection to the real X display. */
2689 sock = x11_connect_display();
2691 /* Allocate a channel for this connection. */
2692 c = channel_new("connected x11 socket",
2693 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
2696 error("x11_input_open: channel_new failed");
2699 c->remote_id = remote_id;
2704 /* Send refusal to the remote host. */
2705 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2706 packet_put_int(remote_id);
2708 /* Send a confirmation to the remote host. */
2709 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2710 packet_put_int(remote_id);
2711 packet_put_int(c->self);
2716 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
2718 deny_input_open(int type, int plen, void *ctxt)
2720 int rchan = packet_get_int();
2722 case SSH_SMSG_AGENT_OPEN:
2723 error("Warning: ssh server tried agent forwarding.");
2725 case SSH_SMSG_X11_OPEN:
2726 error("Warning: ssh server tried X11 forwarding.");
2729 error("deny_input_open: type %d plen %d", type, plen);
2732 error("Warning: this is probably a break in attempt by a malicious server.");
2733 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2734 packet_put_int(rchan);
2739 * Requests forwarding of X11 connections, generates fake authentication
2740 * data, and enables authentication spoofing.
2741 * This should be called in the client only.
2744 x11_request_forwarding_with_spoofing(int client_session_id,
2745 const char *proto, const char *data)
2747 u_int data_len = (u_int) strlen(data) / 2;
2748 u_int i, value, len;
2754 cp = getenv("DISPLAY");
2756 cp = strchr(cp, ':');
2758 cp = strchr(cp, '.');
2760 screen_number = atoi(cp + 1);
2764 /* Save protocol name. */
2765 x11_saved_proto = xstrdup(proto);
2768 * Extract real authentication data and generate fake data of the
2771 x11_saved_data = xmalloc(data_len);
2772 x11_fake_data = xmalloc(data_len);
2773 for (i = 0; i < data_len; i++) {
2774 if (sscanf(data + 2 * i, "%2x", &value) != 1)
2775 fatal("x11_request_forwarding: bad authentication data: %.100s", data);
2777 rand = arc4random();
2778 x11_saved_data[i] = value;
2779 x11_fake_data[i] = rand & 0xff;
2782 x11_saved_data_len = data_len;
2783 x11_fake_data_len = data_len;
2785 /* Convert the fake data into hex. */
2786 len = 2 * data_len + 1;
2787 new_data = xmalloc(len);
2788 for (i = 0; i < data_len; i++)
2789 snprintf(new_data + 2 * i, len - 2 * i,
2790 "%02x", (u_char) x11_fake_data[i]);
2792 /* Send the request packet. */
2794 channel_request_start(client_session_id, "x11-req", 0);
2795 packet_put_char(0); /* XXX bool single connection */
2797 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
2799 packet_put_cstring(proto);
2800 packet_put_cstring(new_data);
2801 packet_put_int(screen_number);
2803 packet_write_wait();
2808 /* -- agent forwarding */
2810 /* Sends a message to the server to request authentication fd forwarding. */
2813 auth_request_forwarding()
2815 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
2817 packet_write_wait();
2821 * Returns the name of the forwarded authentication socket. Returns NULL if
2822 * there is no forwarded authentication socket. The returned value points to
2827 auth_get_socket_name()
2829 return auth_sock_name;
2832 /* removes the agent forwarding socket */
2835 auth_sock_cleanup_proc(void *_pw)
2837 struct passwd *pw = _pw;
2839 if (auth_sock_name) {
2840 temporarily_use_uid(pw);
2841 unlink(auth_sock_name);
2842 rmdir(auth_sock_dir);
2843 auth_sock_name = NULL;
2849 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
2850 * This starts forwarding authentication requests.
2854 auth_input_request_forwarding(struct passwd * pw)
2858 struct sockaddr_un sunaddr;
2860 if (auth_get_socket_name() != NULL) {
2861 error("authentication forwarding requested twice.");
2865 /* Temporarily drop privileged uid for mkdir/bind. */
2866 temporarily_use_uid(pw);
2868 /* Allocate a buffer for the socket name, and format the name. */
2869 auth_sock_name = xmalloc(MAXPATHLEN);
2870 auth_sock_dir = xmalloc(MAXPATHLEN);
2871 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
2873 /* Create private directory for socket */
2874 if (mkdtemp(auth_sock_dir) == NULL) {
2875 packet_send_debug("Agent forwarding disabled: "
2876 "mkdtemp() failed: %.100s", strerror(errno));
2878 xfree(auth_sock_name);
2879 xfree(auth_sock_dir);
2880 auth_sock_name = NULL;
2881 auth_sock_dir = NULL;
2884 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d",
2885 auth_sock_dir, (int) getpid());
2887 /* delete agent socket on fatal() */
2888 fatal_add_cleanup(auth_sock_cleanup_proc, pw);
2890 /* Create the socket. */
2891 sock = socket(AF_UNIX, SOCK_STREAM, 0);
2893 packet_disconnect("socket: %.100s", strerror(errno));
2895 /* Bind it to the name. */
2896 memset(&sunaddr, 0, sizeof(sunaddr));
2897 sunaddr.sun_family = AF_UNIX;
2898 strncpy(sunaddr.sun_path, auth_sock_name,
2899 sizeof(sunaddr.sun_path));
2901 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
2902 packet_disconnect("bind: %.100s", strerror(errno));
2904 /* Restore the privileged uid. */
2907 /* Start listening on the socket. */
2908 if (listen(sock, 5) < 0)
2909 packet_disconnect("listen: %.100s", strerror(errno));
2911 /* Allocate a channel for the authentication agent socket. */
2912 nc = channel_new("auth socket",
2913 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
2914 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
2915 0, xstrdup("auth socket"), 1);
2917 error("auth_input_request_forwarding: channel_new failed");
2918 auth_sock_cleanup_proc(pw);
2919 fatal_remove_cleanup(auth_sock_cleanup_proc, pw);
2923 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
2927 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
2930 auth_input_open_request(int type, int plen, void *ctxt)
2933 int remote_id, sock;
2936 packet_integrity_check(plen, 4, type);
2938 /* Read the remote channel number from the message. */
2939 remote_id = packet_get_int();
2942 * Get a connection to the local authentication agent (this may again
2945 sock = ssh_get_authentication_socket();
2948 * If we could not connect the agent, send an error message back to
2949 * the server. This should never happen unless the agent dies,
2950 * because authentication forwarding is only enabled if we have an
2954 name = xstrdup("authentication agent connection");
2955 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
2956 -1, 0, 0, 0, name, 1);
2958 error("auth_input_open_request: channel_new failed");
2962 c->remote_id = remote_id;
2967 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2968 packet_put_int(remote_id);
2970 /* Send a confirmation to the remote host. */
2971 debug("Forwarding authentication connection.");
2972 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
2973 packet_put_int(remote_id);
2974 packet_put_int(c->self);