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dtucker@openbsd.org73ddb252018-07-27 05:13:02 +00001/* $OpenBSD: serverloop.c,v 1.209 2018/07/27 05:13:02 dtucker Exp $ */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002/*
Damien Miller95def091999-11-25 00:26:21 +11003 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11006 * Server main loop for handling the interactive session.
Damien Millere4340be2000-09-16 13:29:08 +11007 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 *
Damien Millerefb4afe2000-04-12 18:45:05 +100014 * SSH2 support by Markus Friedl.
Ben Lindstrom44697232001-07-04 03:32:30 +000015 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +110016 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Millerefb4afe2000-04-12 18:45:05 +100036 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100037
38#include "includes.h"
Damien Miller9cf6d072006-03-15 11:29:24 +110039
40#include <sys/types.h>
41#include <sys/wait.h>
Damien Miller8ec8c3e2006-07-10 20:35:38 +100042#include <sys/socket.h>
Damien Miller9aec9192006-08-05 10:57:45 +100043#ifdef HAVE_SYS_TIME_H
44# include <sys/time.h>
45#endif
Damien Miller8ec8c3e2006-07-10 20:35:38 +100046
47#include <netinet/in.h>
Damien Miller99bd21e2006-03-15 11:11:28 +110048
Darren Tucker39972492006-07-12 22:22:46 +100049#include <errno.h>
Damien Miller57cf6382006-07-10 21:13:46 +100050#include <fcntl.h>
Damien Miller9f2abc42006-07-10 20:53:08 +100051#include <pwd.h>
Damien Miller6ff3cad2006-03-15 11:52:09 +110052#include <signal.h>
Damien Millere3476ed2006-07-24 14:13:33 +100053#include <string.h>
Damien Miller99bd21e2006-03-15 11:11:28 +110054#include <termios.h>
Damien Miller1cdde6f2006-07-24 14:07:35 +100055#include <unistd.h>
Damien Millerd7834352006-08-05 12:39:39 +100056#include <stdarg.h>
Damien Miller69b69aa2000-10-28 14:19:58 +110057
Damien Millerb84886b2008-05-19 15:05:07 +100058#include "openbsd-compat/sys-queue.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100059#include "xmalloc.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100060#include "packet.h"
markus@openbsd.orgc3cb7792018-07-09 21:29:36 +000061#include "sshbuf.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000062#include "log.h"
Damien Miller7acefbb2014-07-18 14:11:24 +100063#include "misc.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100064#include "servconf.h"
Damien Miller16aed052002-09-22 01:26:27 +100065#include "canohost.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000066#include "sshpty.h"
Ben Lindstromc7637672001-06-09 00:36:26 +000067#include "channels.h"
Damien Millerb38eff82000-04-01 11:09:21 +100068#include "compat.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100069#include "ssh2.h"
markus@openbsd.org5467fbc2018-07-11 18:53:29 +000070#include "sshkey.h"
Damien Millerd7834352006-08-05 12:39:39 +100071#include "cipher.h"
72#include "kex.h"
73#include "hostfile.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000074#include "auth.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100075#include "session.h"
Damien Millerb38eff82000-04-01 11:09:21 +100076#include "dispatch.h"
Damien Millerf6d9e222000-06-18 14:50:44 +100077#include "auth-options.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000078#include "serverloop.h"
djm@openbsd.org523463a2015-02-16 22:13:32 +000079#include "ssherr.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100080
Damien Miller50a41ed2000-10-16 12:14:42 +110081extern ServerOptions options;
82
Ben Lindstrom8ac91062001-04-04 17:57:54 +000083/* XXX */
Darren Tucker3e33cec2003-10-02 16:12:36 +100084extern Authctxt *the_authctxt;
djm@openbsd.org7c856852018-03-03 03:15:51 +000085extern struct sshauthopt *auth_opts;
Damien Miller24ecf612005-11-05 15:16:52 +110086extern int use_privsep;
Ben Lindstrom8ac91062001-04-04 17:57:54 +000087
Darren Tucker8901fa92008-06-11 09:34:01 +100088static int no_more_sessions = 0; /* Disallow further sessions. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100089
Damien Miller5428f641999-11-25 11:54:57 +110090/*
91 * This SIGCHLD kludge is used to detect when the child exits. The server
92 * will exit after that, as soon as forwarded connections have terminated.
93 */
Ben Lindstrombba81212001-06-25 05:01:22 +000094
Ben Lindstrom5e71c542001-12-06 16:48:14 +000095static volatile sig_atomic_t child_terminated = 0; /* The child has terminated. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100096
Damien Miller24ecf612005-11-05 15:16:52 +110097/* Cleanup on signals (!use_privsep case only) */
98static volatile sig_atomic_t received_sigterm = 0;
99
Ben Lindstrombba81212001-06-25 05:01:22 +0000100/* prototypes */
101static void server_init_dispatch(void);
Damien Millerb38eff82000-04-01 11:09:21 +1000102
djm@openbsd.orgb7548b12017-10-23 05:08:00 +0000103/* requested tunnel forwarding interface(s), shared with session.c */
104char *tun_fwd_ifnames = NULL;
105
dtucker@openbsd.org73ddb252018-07-27 05:13:02 +0000106/* returns 1 if bind to specified port by specified user is permitted */
107static int
108bind_permitted(int port, uid_t uid)
109{
110 if (use_privsep)
111 return 1; /* allow system to decide */
112 if (port < IPPORT_RESERVED && uid != 0)
113 return 0;
114 return 1;
115}
116
Damien Millerf6681a32001-12-21 14:53:11 +1100117/*
118 * we write to this pipe if a SIGCHLD is caught in order to avoid
119 * the race between select() and child_terminated
120 */
121static int notify_pipe[2];
122static void
123notify_setup(void)
124{
125 if (pipe(notify_pipe) < 0) {
126 error("pipe(notify_pipe) failed %s", strerror(errno));
Damien Miller814ace02011-05-20 19:02:47 +1000127 } else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
128 (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
Damien Millerf6681a32001-12-21 14:53:11 +1100129 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
130 close(notify_pipe[0]);
131 close(notify_pipe[1]);
132 } else {
133 set_nonblock(notify_pipe[0]);
134 set_nonblock(notify_pipe[1]);
135 return;
136 }
137 notify_pipe[0] = -1; /* read end */
138 notify_pipe[1] = -1; /* write end */
139}
140static void
141notify_parent(void)
142{
143 if (notify_pipe[1] != -1)
Darren Tuckerdbee3082013-05-16 20:32:29 +1000144 (void)write(notify_pipe[1], "", 1);
Damien Millerf6681a32001-12-21 14:53:11 +1100145}
146static void
147notify_prepare(fd_set *readset)
148{
149 if (notify_pipe[0] != -1)
150 FD_SET(notify_pipe[0], readset);
151}
152static void
153notify_done(fd_set *readset)
154{
155 char c;
156
157 if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
158 while (read(notify_pipe[0], &c, 1) != -1)
djm@openbsd.org027607f2018-06-08 01:55:40 +0000159 debug2("%s: reading", __func__);
Damien Millerf6681a32001-12-21 14:53:11 +1100160}
161
Damien Millerf0b15df2006-03-26 13:59:20 +1100162/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000163static void
Damien Miller95def091999-11-25 00:26:21 +1100164sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000165{
Damien Miller95def091999-11-25 00:26:21 +1100166 int save_errno = errno;
Damien Millerefb4afe2000-04-12 18:45:05 +1000167 child_terminated = 1;
Damien Millerf6681a32001-12-21 14:53:11 +1100168 notify_parent();
Damien Millerefb4afe2000-04-12 18:45:05 +1000169 errno = save_errno;
170}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000171
Damien Millerf0b15df2006-03-26 13:59:20 +1100172/*ARGSUSED*/
Damien Miller24ecf612005-11-05 15:16:52 +1100173static void
174sigterm_handler(int sig)
175{
176 received_sigterm = sig;
177}
178
Damien Miller8c3902a2001-10-10 15:01:40 +1000179static void
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000180client_alive_check(struct ssh *ssh)
Damien Miller8c3902a2001-10-10 15:01:40 +1000181{
Damien Millerb5820f42003-12-17 16:27:32 +1100182 int channel_id;
dtucker@openbsd.org48c23a32017-12-10 05:55:29 +0000183 char remote_id[512];
Damien Miller056cf732002-01-22 23:21:39 +1100184
Damien Miller8c3902a2001-10-10 15:01:40 +1000185 /* timeout, check to see how many we have had */
Darren Tuckerf7288d72009-06-21 18:12:20 +1000186 if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
dtucker@openbsd.org48c23a32017-12-10 05:55:29 +0000187 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
188 logit("Timeout, client not responding from %s", remote_id);
Damien Miller985a4482006-10-24 03:02:41 +1000189 cleanup_exit(255);
190 }
Damien Miller8c3902a2001-10-10 15:01:40 +1000191
Damien Miller8c3902a2001-10-10 15:01:40 +1000192 /*
Damien Millerb5820f42003-12-17 16:27:32 +1100193 * send a bogus global/channel request with "wantreply",
Damien Miller8c3902a2001-10-10 15:01:40 +1000194 * we should get back a failure
195 */
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000196 if ((channel_id = channel_find_open(ssh)) == -1) {
Damien Millerb5820f42003-12-17 16:27:32 +1100197 packet_start(SSH2_MSG_GLOBAL_REQUEST);
198 packet_put_cstring("keepalive@openssh.com");
199 packet_put_char(1); /* boolean: want reply */
200 } else {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000201 channel_request_start(ssh, channel_id,
202 "keepalive@openssh.com", 1);
Damien Millerb5820f42003-12-17 16:27:32 +1100203 }
Damien Miller8c3902a2001-10-10 15:01:40 +1000204 packet_send();
205}
206
Damien Miller95def091999-11-25 00:26:21 +1100207/*
208 * Sleep in select() until we can do something. This will initialize the
209 * select masks. Upon return, the masks will indicate which descriptors
210 * have data or can accept data. Optionally, a maximum time can be specified
211 * for the duration of the wait (0 = infinite).
212 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000213static void
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000214wait_until_can_do_something(struct ssh *ssh,
215 int connection_in, int connection_out,
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000216 fd_set **readsetp, fd_set **writesetp, int *maxfdp,
djm@openbsd.org988e4292016-03-04 03:35:44 +0000217 u_int *nallocp, u_int64_t max_time_ms)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000218{
Damien Miller95def091999-11-25 00:26:21 +1100219 struct timeval tv, *tvp;
220 int ret;
Damien Miller6c6da332012-06-20 22:31:26 +1000221 time_t minwait_secs = 0;
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000222 int client_alive_scheduled = 0;
dtucker@openbsd.orgb60ff202017-08-11 03:58:36 +0000223 static time_t last_client_time;
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000224
Damien Millera6508752012-04-22 11:21:10 +1000225 /* Allocate and update select() masks for channel descriptors. */
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000226 channel_prepare_select(ssh, readsetp, writesetp, maxfdp,
djm@openbsd.org71e5a532017-08-30 03:59:08 +0000227 nallocp, &minwait_secs);
Damien Millera6508752012-04-22 11:21:10 +1000228
djm@openbsd.org988e4292016-03-04 03:35:44 +0000229 /* XXX need proper deadline system for rekey/client alive */
Damien Millera6508752012-04-22 11:21:10 +1000230 if (minwait_secs != 0)
deraadt@openbsd.org9136ec12016-09-12 01:22:38 +0000231 max_time_ms = MINIMUM(max_time_ms, (u_int)minwait_secs * 1000);
Damien Millera6508752012-04-22 11:21:10 +1000232
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000233 /*
Damien Miller9f0f5c62001-12-21 14:45:46 +1100234 * if using client_alive, set the max timeout accordingly,
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000235 * and indicate that this particular timeout was for client
236 * alive by setting the client_alive_scheduled flag.
237 *
238 * this could be randomized somewhat to make traffic
Damien Miller9f0f5c62001-12-21 14:45:46 +1100239 * analysis more difficult, but we're not doing it yet.
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000240 */
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000241 if (options.client_alive_interval) {
djm@openbsd.org988e4292016-03-04 03:35:44 +0000242 uint64_t keepalive_ms =
243 (uint64_t)options.client_alive_interval * 1000;
244
Ben Lindstrom2f0304c2001-04-29 19:49:14 +0000245 client_alive_scheduled = 1;
djm@openbsd.org988e4292016-03-04 03:35:44 +0000246 if (max_time_ms == 0 || max_time_ms > keepalive_ms)
247 max_time_ms = keepalive_ms;
Ben Lindstrom36857f62001-07-18 15:48:57 +0000248 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000249
Damien Milleraf5f2e62001-10-10 15:01:16 +1000250#if 0
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000251 /* wrong: bad condition XXX */
252 if (channel_not_very_much_buffered_data())
Damien Milleraf5f2e62001-10-10 15:01:16 +1000253#endif
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000254 FD_SET(connection_in, *readsetp);
Damien Millerf6681a32001-12-21 14:53:11 +1100255 notify_prepare(*readsetp);
Damien Miller95def091999-11-25 00:26:21 +1100256
Damien Miller5428f641999-11-25 11:54:57 +1100257 /*
258 * If we have buffered packet data going to the client, mark that
259 * descriptor.
260 */
Damien Miller95def091999-11-25 00:26:21 +1100261 if (packet_have_data_to_write())
Damien Miller5e953212001-01-30 09:14:00 +1100262 FD_SET(connection_out, *writesetp);
Damien Miller95def091999-11-25 00:26:21 +1100263
Damien Miller5428f641999-11-25 11:54:57 +1100264 /*
265 * If child has terminated and there is enough buffer space to read
266 * from it, then read as much as is available and exit.
267 */
Damien Miller95def091999-11-25 00:26:21 +1100268 if (child_terminated && packet_not_very_much_data_to_write())
djm@openbsd.org988e4292016-03-04 03:35:44 +0000269 if (max_time_ms == 0 || client_alive_scheduled)
270 max_time_ms = 100;
Damien Miller95def091999-11-25 00:26:21 +1100271
djm@openbsd.org988e4292016-03-04 03:35:44 +0000272 if (max_time_ms == 0)
Damien Miller95def091999-11-25 00:26:21 +1100273 tvp = NULL;
274 else {
djm@openbsd.org988e4292016-03-04 03:35:44 +0000275 tv.tv_sec = max_time_ms / 1000;
276 tv.tv_usec = 1000 * (max_time_ms % 1000);
Damien Miller95def091999-11-25 00:26:21 +1100277 tvp = &tv;
278 }
279
280 /* Wait for something to happen, or the timeout to expire. */
Damien Miller5e953212001-01-30 09:14:00 +1100281 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
Damien Miller95def091999-11-25 00:26:21 +1100282
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000283 if (ret == -1) {
Damien Miller79faeff2001-11-12 11:06:32 +1100284 memset(*readsetp, 0, *nallocp);
285 memset(*writesetp, 0, *nallocp);
Damien Miller95def091999-11-25 00:26:21 +1100286 if (errno != EINTR)
287 error("select: %.100s", strerror(errno));
dtucker@openbsd.orgb60ff202017-08-11 03:58:36 +0000288 } else if (client_alive_scheduled) {
289 time_t now = monotime();
290
291 if (ret == 0) { /* timeout */
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000292 client_alive_check(ssh);
dtucker@openbsd.orgb60ff202017-08-11 03:58:36 +0000293 } else if (FD_ISSET(connection_in, *readsetp)) {
294 last_client_time = now;
295 } else if (last_client_time != 0 && last_client_time +
dtucker@openbsd.org42a8f8b2017-08-11 04:16:35 +0000296 options.client_alive_interval <= now) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000297 client_alive_check(ssh);
dtucker@openbsd.orgb60ff202017-08-11 03:58:36 +0000298 last_client_time = now;
299 }
300 }
Damien Millerf6681a32001-12-21 14:53:11 +1100301
302 notify_done(*readsetp);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000303}
304
Damien Miller95def091999-11-25 00:26:21 +1100305/*
306 * Processes input from the client and the program. Input data is stored
307 * in buffers and processed later.
308 */
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000309static int
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000310process_input(struct ssh *ssh, fd_set *readset, int connection_in)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000311{
Damien Miller95def091999-11-25 00:26:21 +1100312 int len;
313 char buf[16384];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000314
Damien Miller95def091999-11-25 00:26:21 +1100315 /* Read and buffer any input data from the client. */
316 if (FD_ISSET(connection_in, readset)) {
markus@openbsd.orga3068632016-01-14 16:17:39 +0000317 len = read(connection_in, buf, sizeof(buf));
Damien Miller95def091999-11-25 00:26:21 +1100318 if (len == 0) {
djm@openbsd.org95767262016-03-07 19:02:43 +0000319 verbose("Connection closed by %.100s port %d",
320 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000321 return -1;
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000322 } else if (len < 0) {
Damien Millerd8968ad2008-07-04 23:10:49 +1000323 if (errno != EINTR && errno != EAGAIN &&
324 errno != EWOULDBLOCK) {
Damien Miller16aed052002-09-22 01:26:27 +1000325 verbose("Read error from remote host "
djm@openbsd.org95767262016-03-07 19:02:43 +0000326 "%.100s port %d: %.100s",
327 ssh_remote_ipaddr(ssh),
328 ssh_remote_port(ssh), strerror(errno));
Darren Tucker3e33cec2003-10-02 16:12:36 +1000329 cleanup_exit(255);
Damien Millerdcb6ecd2000-05-17 22:34:22 +1000330 }
331 } else {
332 /* Buffer any received data. */
333 packet_process_incoming(buf, len);
Damien Miller95def091999-11-25 00:26:21 +1100334 }
Damien Miller95def091999-11-25 00:26:21 +1100335 }
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000336 return 0;
Damien Miller95def091999-11-25 00:26:21 +1100337}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000338
Damien Miller95def091999-11-25 00:26:21 +1100339/*
340 * Sends data from internal buffers to client program stdin.
341 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000342static void
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000343process_output(fd_set *writeset, int connection_out)
Damien Miller95def091999-11-25 00:26:21 +1100344{
Damien Miller95def091999-11-25 00:26:21 +1100345 /* Send any buffered packet data to the client. */
346 if (FD_ISSET(connection_out, writeset))
347 packet_write_poll();
348}
349
Ben Lindstrombba81212001-06-25 05:01:22 +0000350static void
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000351process_buffered_input_packets(struct ssh *ssh)
Damien Millerb38eff82000-04-01 11:09:21 +1000352{
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000353 ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, NULL);
Damien Millerb38eff82000-04-01 11:09:21 +1000354}
355
Damien Miller3ec27592001-10-12 11:35:04 +1000356static void
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000357collect_children(struct ssh *ssh)
Damien Miller3ec27592001-10-12 11:35:04 +1000358{
359 pid_t pid;
360 sigset_t oset, nset;
361 int status;
362
363 /* block SIGCHLD while we check for dead children */
364 sigemptyset(&nset);
365 sigaddset(&nset, SIGCHLD);
366 sigprocmask(SIG_BLOCK, &nset, &oset);
367 if (child_terminated) {
Damien Millerec04f362006-03-15 12:01:34 +1100368 debug("Received SIGCHLD.");
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000369 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
370 (pid < 0 && errno == EINTR))
371 if (pid > 0)
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000372 session_close_by_pid(ssh, pid, status);
Damien Miller3ec27592001-10-12 11:35:04 +1000373 child_terminated = 0;
374 }
375 sigprocmask(SIG_SETMASK, &oset, NULL);
376}
377
Damien Miller4af51302000-04-16 11:18:38 +1000378void
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000379server_loop2(struct ssh *ssh, Authctxt *authctxt)
Damien Millerefb4afe2000-04-12 18:45:05 +1000380{
Damien Miller5e953212001-01-30 09:14:00 +1100381 fd_set *readset = NULL, *writeset = NULL;
djm@openbsd.org19bcf2e2016-02-08 10:57:07 +0000382 int max_fd;
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000383 u_int nalloc = 0, connection_in, connection_out;
Darren Tucker5f96f3b2013-05-16 20:29:28 +1000384 u_int64_t rekey_timeout_ms = 0;
Damien Millerefb4afe2000-04-12 18:45:05 +1000385
386 debug("Entering interactive session for SSH2.");
387
Darren Tucker389125b2018-02-15 21:43:01 +1100388 signal(SIGCHLD, sigchld_handler);
Damien Millerefb4afe2000-04-12 18:45:05 +1000389 child_terminated = 0;
390 connection_in = packet_get_connection_in();
391 connection_out = packet_get_connection_out();
Damien Miller5e953212001-01-30 09:14:00 +1100392
Damien Miller24ecf612005-11-05 15:16:52 +1100393 if (!use_privsep) {
394 signal(SIGTERM, sigterm_handler);
395 signal(SIGINT, sigterm_handler);
396 signal(SIGQUIT, sigterm_handler);
397 }
398
Damien Millerf6681a32001-12-21 14:53:11 +1100399 notify_setup();
400
deraadt@openbsd.org9136ec12016-09-12 01:22:38 +0000401 max_fd = MAXIMUM(connection_in, connection_out);
402 max_fd = MAXIMUM(max_fd, notify_pipe[0]);
Damien Millerf6681a32001-12-21 14:53:11 +1100403
Damien Millerefb4afe2000-04-12 18:45:05 +1000404 server_init_dispatch();
405
406 for (;;) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000407 process_buffered_input_packets(ssh);
Ben Lindstrom8e312f32001-04-04 23:50:21 +0000408
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000409 if (!ssh_packet_is_rekeying(ssh) &&
djm@openbsd.org19bcf2e2016-02-08 10:57:07 +0000410 packet_not_very_much_data_to_write())
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000411 channel_output_poll(ssh);
412 if (options.rekey_interval > 0 && !ssh_packet_is_rekeying(ssh))
Darren Tucker5f96f3b2013-05-16 20:29:28 +1000413 rekey_timeout_ms = packet_get_rekey_timeout() * 1000;
414 else
415 rekey_timeout_ms = 0;
416
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000417 wait_until_can_do_something(ssh, connection_in, connection_out,
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000418 &readset, &writeset, &max_fd, &nalloc, rekey_timeout_ms);
Damien Miller52b77be2001-10-10 15:14:37 +1000419
Damien Miller24ecf612005-11-05 15:16:52 +1100420 if (received_sigterm) {
Darren Tucker3e1027c2012-12-07 13:07:46 +1100421 logit("Exiting on signal %d", (int)received_sigterm);
Damien Miller24ecf612005-11-05 15:16:52 +1100422 /* Clean up sessions, utmp, etc. */
423 cleanup_exit(255);
424 }
425
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000426 collect_children(ssh);
427 if (!ssh_packet_is_rekeying(ssh))
428 channel_after_select(ssh, readset, writeset);
429 if (process_input(ssh, readset, connection_in) < 0)
Ben Lindstrome34ab4c2001-04-07 01:12:11 +0000430 break;
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000431 process_output(writeset, connection_out);
Damien Millerefb4afe2000-04-12 18:45:05 +1000432 }
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000433 collect_children(ssh);
Damien Miller3ec27592001-10-12 11:35:04 +1000434
Darren Tuckera627d422013-06-02 07:31:17 +1000435 free(readset);
436 free(writeset);
Damien Miller5e953212001-01-30 09:14:00 +1100437
Damien Miller52b77be2001-10-10 15:14:37 +1000438 /* free all channels, no more reads and writes */
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000439 channel_free_all(ssh);
Ben Lindstrom4983d5e2001-07-04 05:17:40 +0000440
Damien Miller3ec27592001-10-12 11:35:04 +1000441 /* free remaining sessions, e.g. remove wtmp entries */
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000442 session_destroy_all(ssh, NULL);
Damien Millerefb4afe2000-04-12 18:45:05 +1000443}
444
markus@openbsd.org3fdc88a2015-01-19 20:07:45 +0000445static int
markus@openbsd.org2ae666a2017-05-30 14:23:52 +0000446server_input_keep_alive(int type, u_int32_t seq, struct ssh *ssh)
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000447{
Damien Millerb5820f42003-12-17 16:27:32 +1100448 debug("Got %d/%u for keepalive", type, seq);
Damien Miller9f0f5c62001-12-21 14:45:46 +1100449 /*
Ben Lindstrom2f0304c2001-04-29 19:49:14 +0000450 * reset timeout, since we got a sane answer from the client.
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000451 * even if this was generated by something other than
452 * the bogus CHANNEL_REQUEST we send for keepalives.
453 */
Darren Tuckerf7288d72009-06-21 18:12:20 +1000454 packet_set_alive_timeouts(0);
markus@openbsd.org3fdc88a2015-01-19 20:07:45 +0000455 return 0;
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000456}
457
Ben Lindstrombba81212001-06-25 05:01:22 +0000458static Channel *
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000459server_request_direct_tcpip(struct ssh *ssh, int *reason, const char **errmsg)
Damien Millerefb4afe2000-04-12 18:45:05 +1000460{
Damien Milleraa5b3f82012-12-03 09:50:54 +1100461 Channel *c = NULL;
Damien Miller4af51302000-04-16 11:18:38 +1000462 char *target, *originator;
Damien Miller3dc71ad2009-01-28 16:31:22 +1100463 u_short target_port, originator_port;
Damien Millerefb4afe2000-04-12 18:45:05 +1000464
Damien Miller4af51302000-04-16 11:18:38 +1000465 target = packet_get_string(NULL);
466 target_port = packet_get_int();
Damien Millerefb4afe2000-04-12 18:45:05 +1000467 originator = packet_get_string(NULL);
468 originator_port = packet_get_int();
Damien Miller48b03fc2002-01-22 23:11:40 +1100469 packet_check_eom();
Damien Millerb1715dc2000-05-30 13:44:51 +1000470
djm@openbsd.org7c856852018-03-03 03:15:51 +0000471 debug("%s: originator %s port %d, target %s port %d", __func__,
472 originator, originator_port, target, target_port);
Damien Millerf6d9e222000-06-18 14:50:44 +1000473
Damien Milleraa5b3f82012-12-03 09:50:54 +1100474 /* XXX fine grained permissions */
475 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
djm@openbsd.org7c856852018-03-03 03:15:51 +0000476 auth_opts->permit_port_forwarding_flag &&
477 !options.disable_forwarding) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000478 c = channel_connect_to_port(ssh, target, target_port,
dtucker@openbsd.org858252f2017-02-01 02:59:09 +0000479 "direct-tcpip", "direct-tcpip", reason, errmsg);
Damien Milleraa5b3f82012-12-03 09:50:54 +1100480 } else {
481 logit("refused local port forward: "
482 "originator %s port %d, target %s port %d",
483 originator, originator_port, target, target_port);
dtucker@openbsd.org858252f2017-02-01 02:59:09 +0000484 if (reason != NULL)
485 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED;
Damien Milleraa5b3f82012-12-03 09:50:54 +1100486 }
Damien Millerbd740252008-05-19 15:37:09 +1000487
Darren Tuckera627d422013-06-02 07:31:17 +1000488 free(originator);
489 free(target);
Damien Millerbd740252008-05-19 15:37:09 +1000490
Ben Lindstrom99c73b32001-05-05 04:09:47 +0000491 return c;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100492}
493
Ben Lindstrombba81212001-06-25 05:01:22 +0000494static Channel *
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000495server_request_direct_streamlocal(struct ssh *ssh)
Damien Miller7acefbb2014-07-18 14:11:24 +1000496{
497 Channel *c = NULL;
498 char *target, *originator;
499 u_short originator_port;
djm@openbsd.org51045862017-01-04 05:37:40 +0000500 struct passwd *pw = the_authctxt->pw;
501
502 if (pw == NULL || !the_authctxt->valid)
djm@openbsd.org7c856852018-03-03 03:15:51 +0000503 fatal("%s: no/invalid user", __func__);
Damien Miller7acefbb2014-07-18 14:11:24 +1000504
505 target = packet_get_string(NULL);
506 originator = packet_get_string(NULL);
507 originator_port = packet_get_int();
508 packet_check_eom();
509
djm@openbsd.org7c856852018-03-03 03:15:51 +0000510 debug("%s: originator %s port %d, target %s", __func__,
Damien Miller7acefbb2014-07-18 14:11:24 +1000511 originator, originator_port, target);
512
513 /* XXX fine grained permissions */
514 if ((options.allow_streamlocal_forwarding & FORWARD_LOCAL) != 0 &&
djm@openbsd.org7c856852018-03-03 03:15:51 +0000515 auth_opts->permit_port_forwarding_flag &&
516 !options.disable_forwarding && (pw->pw_uid == 0 || use_privsep)) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000517 c = channel_connect_to_path(ssh, target,
Damien Miller7acefbb2014-07-18 14:11:24 +1000518 "direct-streamlocal@openssh.com", "direct-streamlocal");
519 } else {
520 logit("refused streamlocal port forward: "
521 "originator %s port %d, target %s",
522 originator, originator_port, target);
523 }
524
525 free(originator);
526 free(target);
527
528 return c;
529}
530
531static Channel *
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000532server_request_tun(struct ssh *ssh)
Damien Millerd27b9472005-12-13 19:29:02 +1100533{
534 Channel *c = NULL;
djm@openbsd.org7c856852018-03-03 03:15:51 +0000535 int mode, tun, sock;
djm@openbsd.orgb7548b12017-10-23 05:08:00 +0000536 char *tmp, *ifname = NULL;
Damien Millerd27b9472005-12-13 19:29:02 +1100537
Damien Miller7b58e802005-12-13 19:33:19 +1100538 mode = packet_get_int();
539 switch (mode) {
540 case SSH_TUNMODE_POINTOPOINT:
541 case SSH_TUNMODE_ETHERNET:
542 break;
543 default:
544 packet_send_debug("Unsupported tunnel device mode.");
545 return NULL;
546 }
547 if ((options.permit_tun & mode) == 0) {
548 packet_send_debug("Server has rejected tunnel device "
549 "forwarding");
Damien Millerd27b9472005-12-13 19:29:02 +1100550 return NULL;
551 }
552
553 tun = packet_get_int();
djm@openbsd.org7c856852018-03-03 03:15:51 +0000554 if (auth_opts->force_tun_device != -1) {
555 if (tun != SSH_TUNID_ANY && auth_opts->force_tun_device != tun)
Damien Millerd27b9472005-12-13 19:29:02 +1100556 goto done;
djm@openbsd.org7c856852018-03-03 03:15:51 +0000557 tun = auth_opts->force_tun_device;
Damien Millerd27b9472005-12-13 19:29:02 +1100558 }
djm@openbsd.orgb7548b12017-10-23 05:08:00 +0000559 sock = tun_open(tun, mode, &ifname);
Damien Millerd27b9472005-12-13 19:29:02 +1100560 if (sock < 0)
561 goto done;
djm@openbsd.orgb7548b12017-10-23 05:08:00 +0000562 debug("Tunnel forwarding using interface %s", ifname);
Darren Tucker3c511432018-02-13 09:07:29 +1100563
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000564 c = channel_new(ssh, "tun", SSH_CHANNEL_OPEN, sock, sock, -1,
Damien Millerd27b9472005-12-13 19:29:02 +1100565 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
566 c->datagram = 1;
Damien Miller598bbc22005-12-31 16:33:36 +1100567#if defined(SSH_TUN_FILTER)
568 if (mode == SSH_TUNMODE_POINTOPOINT)
Damien Miller871f1e42017-09-12 18:01:35 +1000569 channel_register_filter(ssh, c->self, sys_tun_infilter,
Darren Tucker1cf65ae2008-06-13 05:09:18 +1000570 sys_tun_outfilter, NULL, NULL);
Damien Miller598bbc22005-12-31 16:33:36 +1100571#endif
Damien Millerd27b9472005-12-13 19:29:02 +1100572
djm@openbsd.orgb7548b12017-10-23 05:08:00 +0000573 /*
574 * Update the list of names exposed to the session
575 * XXX remove these if the tunnels are closed (won't matter
576 * much if they are already in the environment though)
577 */
578 tmp = tun_fwd_ifnames;
579 xasprintf(&tun_fwd_ifnames, "%s%s%s",
580 tun_fwd_ifnames == NULL ? "" : tun_fwd_ifnames,
581 tun_fwd_ifnames == NULL ? "" : ",",
582 ifname);
583 free(tmp);
584 free(ifname);
585
Damien Millerd27b9472005-12-13 19:29:02 +1100586 done:
587 if (c == NULL)
588 packet_send_debug("Failed to open the tunnel device.");
589 return c;
590}
591
592static Channel *
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000593server_request_session(struct ssh *ssh)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100594{
Ben Lindstrom99c73b32001-05-05 04:09:47 +0000595 Channel *c;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100596
597 debug("input_session_request");
Damien Miller48b03fc2002-01-22 23:11:40 +1100598 packet_check_eom();
Darren Tucker8901fa92008-06-11 09:34:01 +1000599
600 if (no_more_sessions) {
601 packet_disconnect("Possible attack: attempt to open a session "
602 "after additional sessions disabled");
603 }
604
Damien Miller0bc1bd82000-11-13 22:57:25 +1100605 /*
606 * A server session has no fd to read or write until a
607 * CHANNEL_REQUEST for a shell is made, so we set the type to
608 * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all
609 * CHANNEL_REQUEST messages is registered.
610 */
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000611 c = channel_new(ssh, "session", SSH_CHANNEL_LARVAL,
Ben Lindstrom99c73b32001-05-05 04:09:47 +0000612 -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
Damien Millerb1ca8bb2003-05-14 13:45:42 +1000613 0, "server-session", 1);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000614 if (session_open(the_authctxt, c->self) != 1) {
Ben Lindstrom99c73b32001-05-05 04:09:47 +0000615 debug("session open failed, free channel %d", c->self);
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000616 channel_free(ssh, c);
Ben Lindstrom99c73b32001-05-05 04:09:47 +0000617 return NULL;
618 }
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000619 channel_register_cleanup(ssh, c->self, session_close_by_channel, 0);
Ben Lindstrom99c73b32001-05-05 04:09:47 +0000620 return c;
Damien Millerefb4afe2000-04-12 18:45:05 +1000621}
622
markus@openbsd.org3fdc88a2015-01-19 20:07:45 +0000623static int
markus@openbsd.org2ae666a2017-05-30 14:23:52 +0000624server_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
Damien Millerefb4afe2000-04-12 18:45:05 +1000625{
626 Channel *c = NULL;
627 char *ctype;
dtucker@openbsd.org858252f2017-02-01 02:59:09 +0000628 const char *errmsg = NULL;
629 int rchan, reason = SSH2_OPEN_CONNECT_FAILED;
Ben Lindstrom4fed2be2002-06-25 23:17:36 +0000630 u_int rmaxpack, rwindow, len;
Damien Millerefb4afe2000-04-12 18:45:05 +1000631
632 ctype = packet_get_string(&len);
633 rchan = packet_get_int();
634 rwindow = packet_get_int();
635 rmaxpack = packet_get_int();
636
djm@openbsd.org027607f2018-06-08 01:55:40 +0000637 debug("%s: ctype %s rchan %d win %d max %d", __func__,
Damien Millerefb4afe2000-04-12 18:45:05 +1000638 ctype, rchan, rwindow, rmaxpack);
639
640 if (strcmp(ctype, "session") == 0) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000641 c = server_request_session(ssh);
Damien Millerefb4afe2000-04-12 18:45:05 +1000642 } else if (strcmp(ctype, "direct-tcpip") == 0) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000643 c = server_request_direct_tcpip(ssh, &reason, &errmsg);
Damien Miller7acefbb2014-07-18 14:11:24 +1000644 } else if (strcmp(ctype, "direct-streamlocal@openssh.com") == 0) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000645 c = server_request_direct_streamlocal(ssh);
Damien Millerd27b9472005-12-13 19:29:02 +1100646 } else if (strcmp(ctype, "tun@openssh.com") == 0) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000647 c = server_request_tun(ssh);
Damien Millerefb4afe2000-04-12 18:45:05 +1000648 }
649 if (c != NULL) {
djm@openbsd.org027607f2018-06-08 01:55:40 +0000650 debug("%s: confirm %s", __func__, ctype);
Damien Millerefb4afe2000-04-12 18:45:05 +1000651 c->remote_id = rchan;
djm@openbsd.org9f532292017-09-12 06:35:31 +0000652 c->have_remote_id = 1;
Damien Millerefb4afe2000-04-12 18:45:05 +1000653 c->remote_window = rwindow;
654 c->remote_maxpacket = rmaxpack;
Ben Lindstrom69128662001-05-08 20:07:39 +0000655 if (c->type != SSH_CHANNEL_CONNECTING) {
656 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
657 packet_put_int(c->remote_id);
658 packet_put_int(c->self);
659 packet_put_int(c->local_window);
660 packet_put_int(c->local_maxpacket);
661 packet_send();
662 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000663 } else {
djm@openbsd.org027607f2018-06-08 01:55:40 +0000664 debug("%s: failure %s", __func__, ctype);
Damien Millerefb4afe2000-04-12 18:45:05 +1000665 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
666 packet_put_int(rchan);
dtucker@openbsd.org858252f2017-02-01 02:59:09 +0000667 packet_put_int(reason);
djm@openbsd.org14b5c632018-01-23 05:27:21 +0000668 packet_put_cstring(errmsg ? errmsg : "open failed");
669 packet_put_cstring("");
Damien Millerefb4afe2000-04-12 18:45:05 +1000670 packet_send();
671 }
Darren Tuckera627d422013-06-02 07:31:17 +1000672 free(ctype);
markus@openbsd.org3fdc88a2015-01-19 20:07:45 +0000673 return 0;
Damien Millerefb4afe2000-04-12 18:45:05 +1000674}
675
markus@openbsd.org3fdc88a2015-01-19 20:07:45 +0000676static int
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000677server_input_hostkeys_prove(struct ssh *ssh, struct sshbuf **respp)
djm@openbsd.org523463a2015-02-16 22:13:32 +0000678{
djm@openbsd.org523463a2015-02-16 22:13:32 +0000679 struct sshbuf *resp = NULL;
680 struct sshbuf *sigbuf = NULL;
681 struct sshkey *key = NULL, *key_pub = NULL, *key_prv = NULL;
djm@openbsd.org78607312017-12-18 23:16:23 +0000682 int r, ndx, kexsigtype, use_kexsigtype, success = 0;
djm@openbsd.org523463a2015-02-16 22:13:32 +0000683 const u_char *blob;
684 u_char *sig = 0;
685 size_t blen, slen;
686
687 if ((resp = sshbuf_new()) == NULL || (sigbuf = sshbuf_new()) == NULL)
688 fatal("%s: sshbuf_new", __func__);
689
djm@openbsd.org78607312017-12-18 23:16:23 +0000690 kexsigtype = sshkey_type_plain(
691 sshkey_type_from_name(ssh->kex->hostkey_alg));
djm@openbsd.org523463a2015-02-16 22:13:32 +0000692 while (ssh_packet_remaining(ssh) > 0) {
693 sshkey_free(key);
694 key = NULL;
695 if ((r = sshpkt_get_string_direct(ssh, &blob, &blen)) != 0 ||
696 (r = sshkey_from_blob(blob, blen, &key)) != 0) {
697 error("%s: couldn't parse key: %s",
698 __func__, ssh_err(r));
699 goto out;
700 }
701 /*
702 * Better check that this is actually one of our hostkeys
703 * before attempting to sign anything with it.
704 */
705 if ((ndx = ssh->kex->host_key_index(key, 1, ssh)) == -1) {
706 error("%s: unknown host %s key",
707 __func__, sshkey_type(key));
708 goto out;
709 }
710 /*
711 * XXX refactor: make kex->sign just use an index rather
712 * than passing in public and private keys
713 */
714 if ((key_prv = get_hostkey_by_index(ndx)) == NULL &&
715 (key_pub = get_hostkey_public_by_index(ndx, ssh)) == NULL) {
716 error("%s: can't retrieve hostkey %d", __func__, ndx);
717 goto out;
718 }
719 sshbuf_reset(sigbuf);
720 free(sig);
721 sig = NULL;
djm@openbsd.org78607312017-12-18 23:16:23 +0000722 /*
723 * For RSA keys, prefer to use the signature type negotiated
724 * during KEX to the default (SHA1).
725 */
726 use_kexsigtype = kexsigtype == KEY_RSA &&
727 sshkey_type_plain(key->type) == KEY_RSA;
djm@openbsd.org44732de2015-02-20 22:17:21 +0000728 if ((r = sshbuf_put_cstring(sigbuf,
729 "hostkeys-prove-00@openssh.com")) != 0 ||
730 (r = sshbuf_put_string(sigbuf,
djm@openbsd.org523463a2015-02-16 22:13:32 +0000731 ssh->kex->session_id, ssh->kex->session_id_len)) != 0 ||
djm@openbsd.org523463a2015-02-16 22:13:32 +0000732 (r = sshkey_puts(key, sigbuf)) != 0 ||
733 (r = ssh->kex->sign(key_prv, key_pub, &sig, &slen,
djm@openbsd.org04c7e282017-12-18 02:25:15 +0000734 sshbuf_ptr(sigbuf), sshbuf_len(sigbuf),
djm@openbsd.org78607312017-12-18 23:16:23 +0000735 use_kexsigtype ? ssh->kex->hostkey_alg : NULL, 0)) != 0 ||
djm@openbsd.org523463a2015-02-16 22:13:32 +0000736 (r = sshbuf_put_string(resp, sig, slen)) != 0) {
737 error("%s: couldn't prepare signature: %s",
738 __func__, ssh_err(r));
739 goto out;
740 }
741 }
742 /* Success */
743 *respp = resp;
744 resp = NULL; /* don't free it */
745 success = 1;
746 out:
747 free(sig);
748 sshbuf_free(resp);
749 sshbuf_free(sigbuf);
750 sshkey_free(key);
751 return success;
752}
753
754static int
markus@openbsd.org2ae666a2017-05-30 14:23:52 +0000755server_input_global_request(int type, u_int32_t seq, struct ssh *ssh)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100756{
757 char *rtype;
758 int want_reply;
djm@openbsd.org523463a2015-02-16 22:13:32 +0000759 int r, success = 0, allocated_listen_port = 0;
760 struct sshbuf *resp = NULL;
djm@openbsd.org51045862017-01-04 05:37:40 +0000761 struct passwd *pw = the_authctxt->pw;
762
763 if (pw == NULL || !the_authctxt->valid)
djm@openbsd.org027607f2018-06-08 01:55:40 +0000764 fatal("%s: no/invalid user", __func__);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100765
766 rtype = packet_get_string(NULL);
767 want_reply = packet_get_char();
djm@openbsd.org027607f2018-06-08 01:55:40 +0000768 debug("%s: rtype %s want_reply %d", __func__, rtype, want_reply);
Kevin Stevesef4eea92001-02-05 12:42:17 +0000769
Ben Lindstrom7bb8b492001-03-17 00:47:54 +0000770 /* -R style forwarding */
Damien Miller0bc1bd82000-11-13 22:57:25 +1100771 if (strcmp(rtype, "tcpip-forward") == 0) {
Damien Miller7acefbb2014-07-18 14:11:24 +1000772 struct Forward fwd;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100773
Damien Miller7acefbb2014-07-18 14:11:24 +1000774 memset(&fwd, 0, sizeof(fwd));
775 fwd.listen_host = packet_get_string(NULL);
776 fwd.listen_port = (u_short)packet_get_int();
djm@openbsd.org027607f2018-06-08 01:55:40 +0000777 debug("%s: tcpip-forward listen %s port %d", __func__,
Damien Miller7acefbb2014-07-18 14:11:24 +1000778 fwd.listen_host, fwd.listen_port);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100779
780 /* check permissions */
Damien Milleraa5b3f82012-12-03 09:50:54 +1100781 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
djm@openbsd.org7c856852018-03-03 03:15:51 +0000782 !auth_opts->permit_port_forwarding_flag ||
783 options.disable_forwarding ||
Darren Tucker5f41f032016-04-08 21:14:13 +1000784 (!want_reply && fwd.listen_port == 0) ||
dtucker@openbsd.org1c4ef0b2016-10-23 22:04:05 +0000785 (fwd.listen_port != 0 &&
786 !bind_permitted(fwd.listen_port, pw->pw_uid))) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100787 success = 0;
788 packet_send_debug("Server has disabled port forwarding.");
789 } else {
790 /* Start listening on the port */
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000791 success = channel_setup_remote_fwd_listener(ssh, &fwd,
Damien Miller7acefbb2014-07-18 14:11:24 +1000792 &allocated_listen_port, &options.fwd_opts);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100793 }
Damien Miller7acefbb2014-07-18 14:11:24 +1000794 free(fwd.listen_host);
djm@openbsd.org523463a2015-02-16 22:13:32 +0000795 if ((resp = sshbuf_new()) == NULL)
796 fatal("%s: sshbuf_new", __func__);
djm@openbsd.orgb1d6b392015-11-28 06:41:03 +0000797 if (allocated_listen_port != 0 &&
798 (r = sshbuf_put_u32(resp, allocated_listen_port)) != 0)
djm@openbsd.org523463a2015-02-16 22:13:32 +0000799 fatal("%s: sshbuf_put_u32: %s", __func__, ssh_err(r));
Darren Tuckere7066df2004-05-24 10:18:05 +1000800 } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
Damien Miller7acefbb2014-07-18 14:11:24 +1000801 struct Forward fwd;
Darren Tuckere7066df2004-05-24 10:18:05 +1000802
Damien Miller7acefbb2014-07-18 14:11:24 +1000803 memset(&fwd, 0, sizeof(fwd));
804 fwd.listen_host = packet_get_string(NULL);
805 fwd.listen_port = (u_short)packet_get_int();
Darren Tuckere7066df2004-05-24 10:18:05 +1000806 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
Damien Miller7acefbb2014-07-18 14:11:24 +1000807 fwd.listen_host, fwd.listen_port);
Darren Tuckere7066df2004-05-24 10:18:05 +1000808
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000809 success = channel_cancel_rport_listener(ssh, &fwd);
Damien Miller7acefbb2014-07-18 14:11:24 +1000810 free(fwd.listen_host);
811 } else if (strcmp(rtype, "streamlocal-forward@openssh.com") == 0) {
812 struct Forward fwd;
813
814 memset(&fwd, 0, sizeof(fwd));
815 fwd.listen_path = packet_get_string(NULL);
djm@openbsd.org027607f2018-06-08 01:55:40 +0000816 debug("%s: streamlocal-forward listen path %s", __func__,
Damien Miller7acefbb2014-07-18 14:11:24 +1000817 fwd.listen_path);
818
819 /* check permissions */
820 if ((options.allow_streamlocal_forwarding & FORWARD_REMOTE) == 0
djm@openbsd.org7c856852018-03-03 03:15:51 +0000821 || !auth_opts->permit_port_forwarding_flag ||
822 options.disable_forwarding ||
djm@openbsd.org51045862017-01-04 05:37:40 +0000823 (pw->pw_uid != 0 && !use_privsep)) {
Damien Miller7acefbb2014-07-18 14:11:24 +1000824 success = 0;
djm@openbsd.org51045862017-01-04 05:37:40 +0000825 packet_send_debug("Server has disabled "
826 "streamlocal forwarding.");
Damien Miller7acefbb2014-07-18 14:11:24 +1000827 } else {
828 /* Start listening on the socket */
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000829 success = channel_setup_remote_fwd_listener(ssh,
Damien Miller7acefbb2014-07-18 14:11:24 +1000830 &fwd, NULL, &options.fwd_opts);
831 }
832 free(fwd.listen_path);
833 } else if (strcmp(rtype, "cancel-streamlocal-forward@openssh.com") == 0) {
834 struct Forward fwd;
835
836 memset(&fwd, 0, sizeof(fwd));
837 fwd.listen_path = packet_get_string(NULL);
838 debug("%s: cancel-streamlocal-forward path %s", __func__,
839 fwd.listen_path);
840
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000841 success = channel_cancel_rport_listener(ssh, &fwd);
Damien Miller7acefbb2014-07-18 14:11:24 +1000842 free(fwd.listen_path);
Darren Tucker8901fa92008-06-11 09:34:01 +1000843 } else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
844 no_more_sessions = 1;
845 success = 1;
djm@openbsd.org44732de2015-02-20 22:17:21 +0000846 } else if (strcmp(rtype, "hostkeys-prove-00@openssh.com") == 0) {
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000847 success = server_input_hostkeys_prove(ssh, &resp);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100848 }
849 if (want_reply) {
850 packet_start(success ?
851 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
djm@openbsd.org523463a2015-02-16 22:13:32 +0000852 if (success && resp != NULL)
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000853 ssh_packet_put_raw(ssh, sshbuf_ptr(resp),
djm@openbsd.org523463a2015-02-16 22:13:32 +0000854 sshbuf_len(resp));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100855 packet_send();
856 packet_write_wait();
857 }
Darren Tuckera627d422013-06-02 07:31:17 +1000858 free(rtype);
djm@openbsd.org523463a2015-02-16 22:13:32 +0000859 sshbuf_free(resp);
markus@openbsd.org3fdc88a2015-01-19 20:07:45 +0000860 return 0;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100861}
Damien Miller4f7becb2006-03-26 14:10:14 +1100862
markus@openbsd.org3fdc88a2015-01-19 20:07:45 +0000863static int
markus@openbsd.org2ae666a2017-05-30 14:23:52 +0000864server_input_channel_req(int type, u_int32_t seq, struct ssh *ssh)
Damien Millerc7ef63d2002-02-05 12:21:42 +1100865{
866 Channel *c;
867 int id, reply, success = 0;
868 char *rtype;
869
870 id = packet_get_int();
871 rtype = packet_get_string(NULL);
872 reply = packet_get_char();
873
874 debug("server_input_channel_req: channel %d request %s reply %d",
875 id, rtype, reply);
876
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000877 if ((c = channel_lookup(ssh, id)) == NULL)
Damien Millerc7ef63d2002-02-05 12:21:42 +1100878 packet_disconnect("server_input_channel_req: "
879 "unknown channel %d", id);
Damien Millerbab9bd42008-05-19 16:06:47 +1000880 if (!strcmp(rtype, "eow@openssh.com")) {
881 packet_check_eom();
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000882 chan_rcvd_eow(ssh, c);
Darren Tucker8810dd42008-07-02 22:32:14 +1000883 } else if ((c->type == SSH_CHANNEL_LARVAL ||
884 c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
djm@openbsd.orgdbee4112017-09-12 06:32:07 +0000885 success = session_input_channel_req(ssh, c, rtype);
Damien Millerc5893782014-05-15 13:48:49 +1000886 if (reply && !(c->flags & CHAN_CLOSE_SENT)) {
djm@openbsd.org9f532292017-09-12 06:35:31 +0000887 if (!c->have_remote_id)
888 fatal("%s: channel %d: no remote_id",
889 __func__, c->self);
Damien Millerc7ef63d2002-02-05 12:21:42 +1100890 packet_start(success ?
891 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
892 packet_put_int(c->remote_id);
893 packet_send();
894 }
Darren Tuckera627d422013-06-02 07:31:17 +1000895 free(rtype);
markus@openbsd.org3fdc88a2015-01-19 20:07:45 +0000896 return 0;
Damien Millerc7ef63d2002-02-05 12:21:42 +1100897}
Damien Miller0bc1bd82000-11-13 22:57:25 +1100898
Ben Lindstrombba81212001-06-25 05:01:22 +0000899static void
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000900server_init_dispatch(void)
Damien Millerefb4afe2000-04-12 18:45:05 +1000901{
markus@openbsd.org6cb6dcf2016-08-13 17:47:40 +0000902 debug("server_init_dispatch");
Damien Millerefb4afe2000-04-12 18:45:05 +1000903 dispatch_init(&dispatch_protocol_error);
904 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
905 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
906 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
907 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
908 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
909 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
910 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
Damien Millerc7ef63d2002-02-05 12:21:42 +1100911 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
Damien Millerefb4afe2000-04-12 18:45:05 +1000912 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100913 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
Ben Lindstrom5744dc42001-04-13 23:28:01 +0000914 /* client_alive */
Damien Miller5a33ec62008-12-08 09:55:02 +1100915 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
916 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
Damien Millerb5820f42003-12-17 16:27:32 +1100917 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
918 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
Ben Lindstrom8ac91062001-04-04 17:57:54 +0000919 /* rekeying */
920 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
Damien Millerefb4afe2000-04-12 18:45:05 +1000921}